John McNulty - Academia.edu (original) (raw)

Papers by John McNulty

Research paper thumbnail of A Vertically Integrated Online Radiology Curriculum Developed as a Cognitive Apprenticeship

Academic Radiology, 2016

The principles of Collins' cognitive appr... more The principles of Collins' cognitive apprenticeship model were used to design a radiology curriculum in which medical students practice radiological skills using online case-based modules. The modules are embedded within clinical third-year clerkships, and students are provided with personalized feedback from the instructors. We describe the development of the vertical online radiology curriculum and evaluate its impact on student achievement and learning process using a mixed method approach. The curriculum was developed over a 2-year period. Student participation was voluntary in the first year and mandatory in the second year. For quantitative curriculum evaluation, student metrics for voluntary versus mandatory groups were assessed using independent sample t tests and variable entry method regression analysis. For qualitative analysis, responses from a survey of students about the value of the curriculum were organized into defined themes using consensus coding. Mandatory participation significantly improved (p = .001) the mean radiology examination score (82 %) compared to the voluntary group (73%), suggesting that mandatory participation had a beneficial effect on student performance. Potential preexisting differences in underlying general academic performance were accounted for by including mean basic science grades as the first variable in the regression model. The significant increase in R(2) from .16 to .28 when number of radiology cases completed was added to the original model, and the greater value of the standardized beta for this variable, suggest that the curriculum made a significant contribution to students' radiology examination scores beyond their baseline academic performance. Five dominant themes about curricular characteristics that enhanced student learning and beneficial outcomes emerged from consensus coding. These themes were (1) self-paced design, (2) receiving feedback from faculty, (3) clinical relevance of cases, (4) gaining confidence in interpreting radiological images, and (5) transfer of conceptual knowledge to actual practice. The vertically integrated online radiology curriculum can positively impact student performance and learning process in the context of the cognitive apprenticeship model.

Research paper thumbnail of Organ culture of the goldfish pineal body

Cell Tissue Res, 1984

... Thin sections were cut with a diamond knife and viewed with a RCA EMU-3F or Hitachi HU-11B el... more ... Thin sections were cut with a diamond knife and viewed with a RCA EMU-3F or Hitachi HU-11B electron microscope operated at 50 kV and 75 kV, respectively. ... 1980; Hafeez and Quay 1969; Hafeez and Zerihun 1976; Owman and Riideberg 1970; Van Veen et al. 1980). ...

Research paper thumbnail of Test-taking Behaviors on a Multiple-Choice Exam are Associated with Performance on the Exam and with Learning Style

Research paper thumbnail of Fine Structure of the Pineal Organ in the Troglobytic Fish, Typhlichthyes subterraneous (Pisces: Amblyopsidae)

Cell Tissue Res, 1978

The pineal organ of the blind, cave-dwelling fish, Typhlichythyes subterraneous, was examined wit... more The pineal organ of the blind, cave-dwelling fish, Typhlichythyes subterraneous, was examined with both light and electron microscopes. Like the eyes, the pineal in this troglobytic species was found to be regressed. Two cell types, photoreceptor and supportive cells, were described in the pineal epithelium. Although ganglion cells were not identified, small, unmyelinated nerve fibers were present. The photoreceptor cells had degenerated outer segments. Accordingly, it was suggested that the pineal in this species is not likely to function in photoreception. However, the presence of well developed Golgi bodies, clear and dense-cored vesicles, variable amounts of rough endoplasmic reticulum and glycogen particles indicated that both cell types are metabolically active and may play a role in secretion.

Research paper thumbnail of Pineal gland free amino acids and indoles during postnatal development of the rat : correlations in individuals glands

Journal of Pineal Research, 1990

Free amino acids and indoles were measured by HPLC in single pineal glands of 5-, 10and 20-day-ol... more Free amino acids and indoles were measured by HPLC in single pineal glands of 5-, 10and 20-day-old rats sacrificed during mid-light and mid-dark at each age. Melatonin was detectable in neonates (5-day-old), but day vs night differences in indole constituents did not occur until 10 days of age. Free amino acid steady state levels were high in neonates and there was a tendency for reversal of day vs night differences coinciding with the onset of circadian rhythmicity in indole biosynthesis. High correlations (r > 0.85) existed for taurine vs. glutamate in individual glands regardless of age and time of sacrifice. These findings suggest that taurine and glutamate are biochemically interrelated and that developmental changes in amino acid metabolic pools reflect functional innervation of the gland.

Research paper thumbnail of The structure and development of the pineal complex in the lanternfish Triphoturus mexicanus (Family Myctophidae)

Journal of Morphology

The pineal complex of the lanterfish Triphoturus mexicans was studied by light and electron micro... more The pineal complex of the lanterfish Triphoturus mexicans was studied by light and electron microscopy. Receptor, supportive and ganglion cells were identified in the pineal end-vesicle. The presence of receptor cells and the prominent pineal window strongly suggest a photoreceptor function. Numerous unmyelinated nerve fibers were also found in the end-vesicle. These converge to form part of the pineal stalk. Two kinds of cells (Types I and II) were distinguished in the dorsal sac, which is very well developed. Type I cells are non-ciliated ependymal cells and contain large parcels of glycogen. Type II cells contain large lipid-like inclusions and a distinct band of filaments around the entire periphery of the cell. Receptor cells appear very early in the development of T. mexicanus. They seem to originate from ependymal cells lining the roof of the third ventricle.

Research paper thumbnail of Morphologic evidence for seasonal changes in pineal organ of gold fish, Carassius auratus: A quantitative study

Reproduction Nutrition Development

A quantitative morphologic study of photoreceptor cells in pineal organ of the goldfish was condu... more A quantitative morphologic study of photoreceptor cells in pineal organ of the goldfish was conducted over a period of one year in which the photoperiod-temperature regime simulated the natural environment. Statistically significant seasonal differences were found in cell size, nuclei, nucleoli, mitochondria, endoplasmic reticulum, and Golgi bodies. Peak values generally occurred during the fall and winter months, while minimum values coincided with the reproductive spring and summer seasons. Histological examination of the gonads indicated that the fish followed the normal sexual cycle. These data suggest that the pineal organ is functionally related to photoperiod, temperature, and gonadal maturation in this species.

Research paper thumbnail of The pineal gland in the opossum, Didelphis virginiana. I. Ultrastructural observations

Cell and Tissue Research

ABSTRACT

Research paper thumbnail of Pinealocyte dense-cored vesicles and synaptic ribbons: A correlative ultrastructural-biochemical investigation in rats and mice

Journal of Pineal Research

Dense-cored vesicles (DCV) and synaptic ribbons (SR) were quantified in the pineal gland of the r... more Dense-cored vesicles (DCV) and synaptic ribbons (SR) were quantified in the pineal gland of the rat (Sprague-Dawley) and mouse (Sasco/ICR strain), and day/night differences in frequency of these organelles correlated with levels of indoles determined by high performance liquid chromatography (HPLC). There were significant day/night differences in levels of serotonin (5HT), 5-hydroxyindole acetic acid (5HIAA), N-acetyl-5HT, and melatonin in the rat gland. Melatonin and N-acetyl-5HT were not detectable in the mouse gland sampled every 4 h over the light:dark cycle. The concentrations of 5HT and 5HIAA (ng/microgram protein) were similar in light-adapted rats and mice, but these indoles did not exhibit a circadian rhythm in the mouse gland. Correlative ultrastructural/biochemical results suggest that DCV do not contain physiologically important stores of 5HT since 1) the mouse gland contains the same number of DCV as the rat during the daytime, but only one-tenth the levels of 5HT, 2) day/night 5HT levels do not vary in the mouse gland, but there is a significant nocturnal decline in DCV numbers, and 3) 5HT levels in the rat gland decline at night when DCV numbers increase. Numbers of SR were significantly elevated at night in the rat and mouse, and the frequency of this organelle was similar in both species. However, ribbon-type SR predominated in rat pinealocytes, whereas SR in the mouse were almost exclusively spherical in shape. Day/night differences in SR numbers in the mouse gland suggest that cellular mechanisms regulating the frequency of this organelle do not involve factors related to indole metabolism. Because of the lack of photoperiodic effects on indole metabolism in the mouse pineal gland, this species is a potentially important model to study the functional relationship of pinealocyte organelles to cyclical changes in pineal products other than indoles (e.g., peptide/protein factors).

Research paper thumbnail of Interleukin-1beta expression in the pineal gland of the rat

Journal of Pineal Research

Increasing evidence of the neuroimmunomodulatory role of the pineal gland prompted the present st... more Increasing evidence of the neuroimmunomodulatory role of the pineal gland prompted the present study of pineal gland expression of the immunoregulatory cytokine, interleukin (IL)-1beta. IL-1beta was constitutively expressed in the adult gland, with mRNA levels higher in glands collected during the photophase than in those collected during the scotophase of the light:dark cycle. IL-1beta was up-regulated in pineal cultures, after treatment with either norepinephrine (NE) or interferon (IFN)/lipopolysaccharide (LPS). Although both astrocytes and microglia expressed IL-1beta, important differences were found in the cellular expression of this cytokine under in vivo and in vitro conditions. Increased IL-1beta expression by NE ex vivo and the decline in IL-1 expression at night, when NE levels are elevated, can be explained by immunocytochemical data showing that astrocytes are the predominant cell type expressing this cytokine in vivo, whereas IL-1beta-positive cells are predominantly microglia in pineal explants and dispersed cell cultures. These results are consistent with the hypothesis that cytokines secreted by pineal glia (astrocytes and microglia) may have an important regulatory role in the pineal gland.

Research paper thumbnail of Pinealocyte ultrastructure in mutant mice that lack sympathetic innervation to the pineal gland

Journal of submicroscopic cytology and pathology

Pinealocyte synaptic ribbons (SR) and dense-cored vesicles (DCV) were quantitated in mice that ha... more Pinealocyte synaptic ribbons (SR) and dense-cored vesicles (DCV) were quantitated in mice that have developmental deficiencies in the sympathetic innervation of the pineal gland due to a null mutation for the p75 low-affinity NGF receptor (NGFR). SR exhibited a significant increase whereas there was a significant decline in the frequency of DCV in mutant mice. These findings support the hypothesis that pinealocyte SR and DCV are regulated by neural mechanisms associated with sympathetic system. Ultrastructural characteristics of pinealocytes in mutants included degenerative changes that culminated in the breakdown of cellular components and the accumulation of flocculent-containing vesicles within the cytoplasm. Ribosomal lamellar complexes were also commonly seen in pinealocytes of mutant rats. Although the mutant pineal gland exhibited signs of metabolic imbalances, the cytoarchitecture of the gland (e.g., vascular compartment) and differentiation of the cells were generally unaffected by developmental deficiencies in the gland's innervation.

Research paper thumbnail of Medical Student Use of Computers Correlates with Personality

A recent study evaluating utilization of computer-aided instruction revealed a wide disparity amo... more A recent study evaluating utilization of computer-aided instruction revealed a wide disparity among individual medical student use of computer resources. We tested the hypothesis that the frequency and length of medical student logins to the school's computer network correlated with their personality preferences. Personality preferences of students (n=236) were obtained using the Myers-Briggs Type Indicator (MBTI) test. Computer utilization was quantified from network logs that recorded frequency and length of logins to the network. Individual login data were sorted by personality preference and statistically analyzed. Students with personality preferences that included Introversion (vs. Extroversion), iNtuition (vs. Sensing), Thinking (vs. Feeling) and Perceiving (vs. Judging) tended to use computers the most. Groupings of preferences revealed that "ITP" types logged in significantly more often than "EFJ" types regardless of the N/S dimension. "NTP&quot...

Research paper thumbnail of Morphology of the pineal complex in seven species of lanternfishes (Pisces: Myctophidae)

American Journal of Anatomy, 1977

Research paper thumbnail of Pineal gland transplants into the cerebral hemisphere of newborn rats: a study of the blood brain barrier and innervation

Journal of neural transplantation & plasticity, 1991

Pineal glands from neonatal (0-1 day) Long-Evans black-hooded rats were transplanted into the cer... more Pineal glands from neonatal (0-1 day) Long-Evans black-hooded rats were transplanted into the cerebral hemispheres of litter mates for periods of 1 to 5.5 months. Grafts exhibited differentiated pinealocytes that were intensely immunoreactive for serotonin. Transplant vasculature was permeable to endogenous IgG, comprised fenestrated endothelia with wide pericapillary spaces typical of in situ glands, and had a volume density intermediate to that of surrounding cortex and in situ pineals. Along the periphery, transplant capillaries tended to have continuous endothelia similar to those of host cortex. This peripheral zone was impermeable to endogenous IgG and appeared to increase in size in older grafts. The presence of noradrenergic-like fibers within the perivascular compartment suggested that transplants were innervated by peripheral sympathetic neurons from the superior cervical ganglia. In animals which had been superior cervical ganglionectomized, noradrenergic-like fibers were...

Research paper thumbnail of TGF-beta1 and IL-6 expression in rat pineal gland is regulated by norepinephrine and interleukin-1beta

Histology and histopathology, 2001

The pineal gland is part of the neuroendocrine system that modulates immune functions. Because th... more The pineal gland is part of the neuroendocrine system that modulates immune functions. Because the gland is outside the blood-brain barrier, it is accessible to direct feedback from circulating cytokines that affect the synthesis and secretion of melatonin. Recent studies have suggested that intrinsic immunoregulatory cytokines mediate these neuro-immune interactions under the control of sympathetic innervation to the pineal. This study focused on the expression of transforming growth factor-beta1 (TGF-beta1) and interleukin-6 (IL-6), two cytokines that have important regulatory functions on both neurons and immune cells. Northern blot RNA analysis showed that TGF-beta1, but not IL-6, was expressed in freshly dissected rat pineal glands from neonatal age (1-day-old) into adults. Immunocytochemistry for TGF-beta1 in adult glands revealed localization of this protein in astrocyte-like cells. The sympathetic neurotransmitter norepinephrine (NE) increased transcript levels for both TGF-...

Research paper thumbnail of Distribution of medical school course materials through the web: addressing the issue of printing through an analysis of the costs and utilization

Journal of the Medical Library Association : JMLA, 2002

Research paper thumbnail of Personality preference influences medical student use of specific computer-aided instruction (CAI)

BMC medical education, 2006

The objective of this study was to test the hypothesis that personality preference, which can be ... more The objective of this study was to test the hypothesis that personality preference, which can be related to learning style, influences individual utilization of CAI applications developed specifically for the undergraduate medical curriculum. Personality preferences of students were obtained using the Myers-Briggs Type Indicator (MBTI) test. CAI utilization for individual students was collected from entry logs for two different web-based applications (a discussion forum and a tutorial) used in the basic science course on human anatomy. Individual login data were sorted by personality preference and the data statistically analyzed by 2-way mixed ANOVA and correlation. There was a wide discrepancy in the level and pattern of student use of both CAI. Although individual use of both CAI was positively correlated irrespective of MBTI preference, students with a "Sensing" preference tended to use both CAI applications more than the "iNtuitives". Differences in the leve...

Research paper thumbnail of Chronic Histologic Changes after Vascular Clamping Are Not Associated with Altered Vascular Mechanics

Annals of Vascular Surgery, 1992

The mechanical properties of arteries, along with the histologic and scanning electron microscopy... more The mechanical properties of arteries, along with the histologic and scanning electron microscopy characteristics of the nonatherosclerotic canine arteries, were investigated six months after vascular clamping. Different vessel clamps were applied to 73 sites on the carotid and femoral arteries in five anesthetized dogs. Each clamp was applied for 30 minutes with (a) sufficient force to just occlude blood flow or (b) as tightly as the clamp could be placed. After six months the vessels were excised, filled with barium sulfate suspension, and pressurized in 25 mmHg steps up to 150 mmHg. High resolution contact radiographs were taken at each pressure. These were magnified 35x and measured. Scanning electron microscopy and conventional histology disclosed that the clamped sites exhibited serrated clamp "tracks" in the intima, intimal hyperplasia, and, in a few cases, fractured elastic lamellae. These histologic changes were seen more frequently in the femoral artery than in the carotid artery (p less than .01). The mechanical properties, as determined from radiographic measurements, demonstrated that, for all types of clamps, the luminal diameter, pressure-diameter relationship, and compliance of the clamped vessels were not significantly different from nonclamped control regions (ANOVA). These studies demonstrate that careful application of clamps to nonatherosclerotic arteries produces persistent morphologic changes, but these are not associated with altered mechanical properties of the vessel wall.

Research paper thumbnail of A Three-year Study of Lecture Multimedia Utilization in the Medical Curriculum: Associations with Performances in the Basic Sciences

Medical Science Educator, 2011

... lectures. An alpha = 0.05 was considered statistically significant. All analyses were conduct... more ... lectures. An alpha = 0.05 was considered statistically significant. All analyses were conducted using the software Prism 4.0. ... USA. BALTAZAR ESPIRITU, MD, Department of Medicine, Loyola University Health System, Maywood, IL, USA. ...

Research paper thumbnail of Morphometric analysis of the pineal complex of the golden hamster over a 24-hour light: Dark cycle: I. The superficial pineal in untreated and optically enucleated animals

American Journal of Anatomy, 1984

Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was c... more Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was conducted at both the light and electron microscopic level. The volume of the superficial gland was estimated to be 151 X 10(6) micron 3, comprising 90-94% of the total pineal parenchymal tissue. Analysis of structural rhythms in animals maintained under a 14:10 L:D cycle showed significant 24-hr variations in values for pinealocyte nuclei, nucleoli, rough and smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense-cored vesicles. Peak values for these structures generally occurred at the light:dark interface. These results provide morphological correlates for known rhythmic variations in the synthesis of pineal-gland products. Superficial pineals examined 8 weeks following optic enucleation exhibited a decrease in the volume of pinealocyte nuclei and cytoplasm, while nucleolar size and the amounts of smooth and rough endoplasmic reticulum, Golgi bodies, dense bodies and dense-cored vesicles were enhanced. The latter changes are interpreted as indications of increased synthetic activity by the superficial pineal gland in response to light deprivation.

Research paper thumbnail of A Vertically Integrated Online Radiology Curriculum Developed as a Cognitive Apprenticeship

Academic Radiology, 2016

The principles of Collins' cognitive appr... more The principles of Collins' cognitive apprenticeship model were used to design a radiology curriculum in which medical students practice radiological skills using online case-based modules. The modules are embedded within clinical third-year clerkships, and students are provided with personalized feedback from the instructors. We describe the development of the vertical online radiology curriculum and evaluate its impact on student achievement and learning process using a mixed method approach. The curriculum was developed over a 2-year period. Student participation was voluntary in the first year and mandatory in the second year. For quantitative curriculum evaluation, student metrics for voluntary versus mandatory groups were assessed using independent sample t tests and variable entry method regression analysis. For qualitative analysis, responses from a survey of students about the value of the curriculum were organized into defined themes using consensus coding. Mandatory participation significantly improved (p = .001) the mean radiology examination score (82 %) compared to the voluntary group (73%), suggesting that mandatory participation had a beneficial effect on student performance. Potential preexisting differences in underlying general academic performance were accounted for by including mean basic science grades as the first variable in the regression model. The significant increase in R(2) from .16 to .28 when number of radiology cases completed was added to the original model, and the greater value of the standardized beta for this variable, suggest that the curriculum made a significant contribution to students' radiology examination scores beyond their baseline academic performance. Five dominant themes about curricular characteristics that enhanced student learning and beneficial outcomes emerged from consensus coding. These themes were (1) self-paced design, (2) receiving feedback from faculty, (3) clinical relevance of cases, (4) gaining confidence in interpreting radiological images, and (5) transfer of conceptual knowledge to actual practice. The vertically integrated online radiology curriculum can positively impact student performance and learning process in the context of the cognitive apprenticeship model.

Research paper thumbnail of Organ culture of the goldfish pineal body

Cell Tissue Res, 1984

... Thin sections were cut with a diamond knife and viewed with a RCA EMU-3F or Hitachi HU-11B el... more ... Thin sections were cut with a diamond knife and viewed with a RCA EMU-3F or Hitachi HU-11B electron microscope operated at 50 kV and 75 kV, respectively. ... 1980; Hafeez and Quay 1969; Hafeez and Zerihun 1976; Owman and Riideberg 1970; Van Veen et al. 1980). ...

Research paper thumbnail of Test-taking Behaviors on a Multiple-Choice Exam are Associated with Performance on the Exam and with Learning Style

Research paper thumbnail of Fine Structure of the Pineal Organ in the Troglobytic Fish, Typhlichthyes subterraneous (Pisces: Amblyopsidae)

Cell Tissue Res, 1978

The pineal organ of the blind, cave-dwelling fish, Typhlichythyes subterraneous, was examined wit... more The pineal organ of the blind, cave-dwelling fish, Typhlichythyes subterraneous, was examined with both light and electron microscopes. Like the eyes, the pineal in this troglobytic species was found to be regressed. Two cell types, photoreceptor and supportive cells, were described in the pineal epithelium. Although ganglion cells were not identified, small, unmyelinated nerve fibers were present. The photoreceptor cells had degenerated outer segments. Accordingly, it was suggested that the pineal in this species is not likely to function in photoreception. However, the presence of well developed Golgi bodies, clear and dense-cored vesicles, variable amounts of rough endoplasmic reticulum and glycogen particles indicated that both cell types are metabolically active and may play a role in secretion.

Research paper thumbnail of Pineal gland free amino acids and indoles during postnatal development of the rat : correlations in individuals glands

Journal of Pineal Research, 1990

Free amino acids and indoles were measured by HPLC in single pineal glands of 5-, 10and 20-day-ol... more Free amino acids and indoles were measured by HPLC in single pineal glands of 5-, 10and 20-day-old rats sacrificed during mid-light and mid-dark at each age. Melatonin was detectable in neonates (5-day-old), but day vs night differences in indole constituents did not occur until 10 days of age. Free amino acid steady state levels were high in neonates and there was a tendency for reversal of day vs night differences coinciding with the onset of circadian rhythmicity in indole biosynthesis. High correlations (r > 0.85) existed for taurine vs. glutamate in individual glands regardless of age and time of sacrifice. These findings suggest that taurine and glutamate are biochemically interrelated and that developmental changes in amino acid metabolic pools reflect functional innervation of the gland.

Research paper thumbnail of The structure and development of the pineal complex in the lanternfish Triphoturus mexicanus (Family Myctophidae)

Journal of Morphology

The pineal complex of the lanterfish Triphoturus mexicans was studied by light and electron micro... more The pineal complex of the lanterfish Triphoturus mexicans was studied by light and electron microscopy. Receptor, supportive and ganglion cells were identified in the pineal end-vesicle. The presence of receptor cells and the prominent pineal window strongly suggest a photoreceptor function. Numerous unmyelinated nerve fibers were also found in the end-vesicle. These converge to form part of the pineal stalk. Two kinds of cells (Types I and II) were distinguished in the dorsal sac, which is very well developed. Type I cells are non-ciliated ependymal cells and contain large parcels of glycogen. Type II cells contain large lipid-like inclusions and a distinct band of filaments around the entire periphery of the cell. Receptor cells appear very early in the development of T. mexicanus. They seem to originate from ependymal cells lining the roof of the third ventricle.

Research paper thumbnail of Morphologic evidence for seasonal changes in pineal organ of gold fish, Carassius auratus: A quantitative study

Reproduction Nutrition Development

A quantitative morphologic study of photoreceptor cells in pineal organ of the goldfish was condu... more A quantitative morphologic study of photoreceptor cells in pineal organ of the goldfish was conducted over a period of one year in which the photoperiod-temperature regime simulated the natural environment. Statistically significant seasonal differences were found in cell size, nuclei, nucleoli, mitochondria, endoplasmic reticulum, and Golgi bodies. Peak values generally occurred during the fall and winter months, while minimum values coincided with the reproductive spring and summer seasons. Histological examination of the gonads indicated that the fish followed the normal sexual cycle. These data suggest that the pineal organ is functionally related to photoperiod, temperature, and gonadal maturation in this species.

Research paper thumbnail of The pineal gland in the opossum, Didelphis virginiana. I. Ultrastructural observations

Cell and Tissue Research

ABSTRACT

Research paper thumbnail of Pinealocyte dense-cored vesicles and synaptic ribbons: A correlative ultrastructural-biochemical investigation in rats and mice

Journal of Pineal Research

Dense-cored vesicles (DCV) and synaptic ribbons (SR) were quantified in the pineal gland of the r... more Dense-cored vesicles (DCV) and synaptic ribbons (SR) were quantified in the pineal gland of the rat (Sprague-Dawley) and mouse (Sasco/ICR strain), and day/night differences in frequency of these organelles correlated with levels of indoles determined by high performance liquid chromatography (HPLC). There were significant day/night differences in levels of serotonin (5HT), 5-hydroxyindole acetic acid (5HIAA), N-acetyl-5HT, and melatonin in the rat gland. Melatonin and N-acetyl-5HT were not detectable in the mouse gland sampled every 4 h over the light:dark cycle. The concentrations of 5HT and 5HIAA (ng/microgram protein) were similar in light-adapted rats and mice, but these indoles did not exhibit a circadian rhythm in the mouse gland. Correlative ultrastructural/biochemical results suggest that DCV do not contain physiologically important stores of 5HT since 1) the mouse gland contains the same number of DCV as the rat during the daytime, but only one-tenth the levels of 5HT, 2) day/night 5HT levels do not vary in the mouse gland, but there is a significant nocturnal decline in DCV numbers, and 3) 5HT levels in the rat gland decline at night when DCV numbers increase. Numbers of SR were significantly elevated at night in the rat and mouse, and the frequency of this organelle was similar in both species. However, ribbon-type SR predominated in rat pinealocytes, whereas SR in the mouse were almost exclusively spherical in shape. Day/night differences in SR numbers in the mouse gland suggest that cellular mechanisms regulating the frequency of this organelle do not involve factors related to indole metabolism. Because of the lack of photoperiodic effects on indole metabolism in the mouse pineal gland, this species is a potentially important model to study the functional relationship of pinealocyte organelles to cyclical changes in pineal products other than indoles (e.g., peptide/protein factors).

Research paper thumbnail of Interleukin-1beta expression in the pineal gland of the rat

Journal of Pineal Research

Increasing evidence of the neuroimmunomodulatory role of the pineal gland prompted the present st... more Increasing evidence of the neuroimmunomodulatory role of the pineal gland prompted the present study of pineal gland expression of the immunoregulatory cytokine, interleukin (IL)-1beta. IL-1beta was constitutively expressed in the adult gland, with mRNA levels higher in glands collected during the photophase than in those collected during the scotophase of the light:dark cycle. IL-1beta was up-regulated in pineal cultures, after treatment with either norepinephrine (NE) or interferon (IFN)/lipopolysaccharide (LPS). Although both astrocytes and microglia expressed IL-1beta, important differences were found in the cellular expression of this cytokine under in vivo and in vitro conditions. Increased IL-1beta expression by NE ex vivo and the decline in IL-1 expression at night, when NE levels are elevated, can be explained by immunocytochemical data showing that astrocytes are the predominant cell type expressing this cytokine in vivo, whereas IL-1beta-positive cells are predominantly microglia in pineal explants and dispersed cell cultures. These results are consistent with the hypothesis that cytokines secreted by pineal glia (astrocytes and microglia) may have an important regulatory role in the pineal gland.

Research paper thumbnail of Pinealocyte ultrastructure in mutant mice that lack sympathetic innervation to the pineal gland

Journal of submicroscopic cytology and pathology

Pinealocyte synaptic ribbons (SR) and dense-cored vesicles (DCV) were quantitated in mice that ha... more Pinealocyte synaptic ribbons (SR) and dense-cored vesicles (DCV) were quantitated in mice that have developmental deficiencies in the sympathetic innervation of the pineal gland due to a null mutation for the p75 low-affinity NGF receptor (NGFR). SR exhibited a significant increase whereas there was a significant decline in the frequency of DCV in mutant mice. These findings support the hypothesis that pinealocyte SR and DCV are regulated by neural mechanisms associated with sympathetic system. Ultrastructural characteristics of pinealocytes in mutants included degenerative changes that culminated in the breakdown of cellular components and the accumulation of flocculent-containing vesicles within the cytoplasm. Ribosomal lamellar complexes were also commonly seen in pinealocytes of mutant rats. Although the mutant pineal gland exhibited signs of metabolic imbalances, the cytoarchitecture of the gland (e.g., vascular compartment) and differentiation of the cells were generally unaffected by developmental deficiencies in the gland's innervation.

Research paper thumbnail of Medical Student Use of Computers Correlates with Personality

A recent study evaluating utilization of computer-aided instruction revealed a wide disparity amo... more A recent study evaluating utilization of computer-aided instruction revealed a wide disparity among individual medical student use of computer resources. We tested the hypothesis that the frequency and length of medical student logins to the school's computer network correlated with their personality preferences. Personality preferences of students (n=236) were obtained using the Myers-Briggs Type Indicator (MBTI) test. Computer utilization was quantified from network logs that recorded frequency and length of logins to the network. Individual login data were sorted by personality preference and statistically analyzed. Students with personality preferences that included Introversion (vs. Extroversion), iNtuition (vs. Sensing), Thinking (vs. Feeling) and Perceiving (vs. Judging) tended to use computers the most. Groupings of preferences revealed that "ITP" types logged in significantly more often than "EFJ" types regardless of the N/S dimension. "NTP&quot...

Research paper thumbnail of Morphology of the pineal complex in seven species of lanternfishes (Pisces: Myctophidae)

American Journal of Anatomy, 1977

Research paper thumbnail of Pineal gland transplants into the cerebral hemisphere of newborn rats: a study of the blood brain barrier and innervation

Journal of neural transplantation & plasticity, 1991

Pineal glands from neonatal (0-1 day) Long-Evans black-hooded rats were transplanted into the cer... more Pineal glands from neonatal (0-1 day) Long-Evans black-hooded rats were transplanted into the cerebral hemispheres of litter mates for periods of 1 to 5.5 months. Grafts exhibited differentiated pinealocytes that were intensely immunoreactive for serotonin. Transplant vasculature was permeable to endogenous IgG, comprised fenestrated endothelia with wide pericapillary spaces typical of in situ glands, and had a volume density intermediate to that of surrounding cortex and in situ pineals. Along the periphery, transplant capillaries tended to have continuous endothelia similar to those of host cortex. This peripheral zone was impermeable to endogenous IgG and appeared to increase in size in older grafts. The presence of noradrenergic-like fibers within the perivascular compartment suggested that transplants were innervated by peripheral sympathetic neurons from the superior cervical ganglia. In animals which had been superior cervical ganglionectomized, noradrenergic-like fibers were...

Research paper thumbnail of TGF-beta1 and IL-6 expression in rat pineal gland is regulated by norepinephrine and interleukin-1beta

Histology and histopathology, 2001

The pineal gland is part of the neuroendocrine system that modulates immune functions. Because th... more The pineal gland is part of the neuroendocrine system that modulates immune functions. Because the gland is outside the blood-brain barrier, it is accessible to direct feedback from circulating cytokines that affect the synthesis and secretion of melatonin. Recent studies have suggested that intrinsic immunoregulatory cytokines mediate these neuro-immune interactions under the control of sympathetic innervation to the pineal. This study focused on the expression of transforming growth factor-beta1 (TGF-beta1) and interleukin-6 (IL-6), two cytokines that have important regulatory functions on both neurons and immune cells. Northern blot RNA analysis showed that TGF-beta1, but not IL-6, was expressed in freshly dissected rat pineal glands from neonatal age (1-day-old) into adults. Immunocytochemistry for TGF-beta1 in adult glands revealed localization of this protein in astrocyte-like cells. The sympathetic neurotransmitter norepinephrine (NE) increased transcript levels for both TGF-...

Research paper thumbnail of Distribution of medical school course materials through the web: addressing the issue of printing through an analysis of the costs and utilization

Journal of the Medical Library Association : JMLA, 2002

Research paper thumbnail of Personality preference influences medical student use of specific computer-aided instruction (CAI)

BMC medical education, 2006

The objective of this study was to test the hypothesis that personality preference, which can be ... more The objective of this study was to test the hypothesis that personality preference, which can be related to learning style, influences individual utilization of CAI applications developed specifically for the undergraduate medical curriculum. Personality preferences of students were obtained using the Myers-Briggs Type Indicator (MBTI) test. CAI utilization for individual students was collected from entry logs for two different web-based applications (a discussion forum and a tutorial) used in the basic science course on human anatomy. Individual login data were sorted by personality preference and the data statistically analyzed by 2-way mixed ANOVA and correlation. There was a wide discrepancy in the level and pattern of student use of both CAI. Although individual use of both CAI was positively correlated irrespective of MBTI preference, students with a "Sensing" preference tended to use both CAI applications more than the "iNtuitives". Differences in the leve...

Research paper thumbnail of Chronic Histologic Changes after Vascular Clamping Are Not Associated with Altered Vascular Mechanics

Annals of Vascular Surgery, 1992

The mechanical properties of arteries, along with the histologic and scanning electron microscopy... more The mechanical properties of arteries, along with the histologic and scanning electron microscopy characteristics of the nonatherosclerotic canine arteries, were investigated six months after vascular clamping. Different vessel clamps were applied to 73 sites on the carotid and femoral arteries in five anesthetized dogs. Each clamp was applied for 30 minutes with (a) sufficient force to just occlude blood flow or (b) as tightly as the clamp could be placed. After six months the vessels were excised, filled with barium sulfate suspension, and pressurized in 25 mmHg steps up to 150 mmHg. High resolution contact radiographs were taken at each pressure. These were magnified 35x and measured. Scanning electron microscopy and conventional histology disclosed that the clamped sites exhibited serrated clamp "tracks" in the intima, intimal hyperplasia, and, in a few cases, fractured elastic lamellae. These histologic changes were seen more frequently in the femoral artery than in the carotid artery (p less than .01). The mechanical properties, as determined from radiographic measurements, demonstrated that, for all types of clamps, the luminal diameter, pressure-diameter relationship, and compliance of the clamped vessels were not significantly different from nonclamped control regions (ANOVA). These studies demonstrate that careful application of clamps to nonatherosclerotic arteries produces persistent morphologic changes, but these are not associated with altered mechanical properties of the vessel wall.

Research paper thumbnail of A Three-year Study of Lecture Multimedia Utilization in the Medical Curriculum: Associations with Performances in the Basic Sciences

Medical Science Educator, 2011

... lectures. An alpha = 0.05 was considered statistically significant. All analyses were conduct... more ... lectures. An alpha = 0.05 was considered statistically significant. All analyses were conducted using the software Prism 4.0. ... USA. BALTAZAR ESPIRITU, MD, Department of Medicine, Loyola University Health System, Maywood, IL, USA. ...

Research paper thumbnail of Morphometric analysis of the pineal complex of the golden hamster over a 24-hour light: Dark cycle: I. The superficial pineal in untreated and optically enucleated animals

American Journal of Anatomy, 1984

Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was c... more Morphometric analysis of the superficial pineal gland of intact and blinded golden hamsters was conducted at both the light and electron microscopic level. The volume of the superficial gland was estimated to be 151 X 10(6) micron 3, comprising 90-94% of the total pineal parenchymal tissue. Analysis of structural rhythms in animals maintained under a 14:10 L:D cycle showed significant 24-hr variations in values for pinealocyte nuclei, nucleoli, rough and smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense-cored vesicles. Peak values for these structures generally occurred at the light:dark interface. These results provide morphological correlates for known rhythmic variations in the synthesis of pineal-gland products. Superficial pineals examined 8 weeks following optic enucleation exhibited a decrease in the volume of pinealocyte nuclei and cytoplasm, while nucleolar size and the amounts of smooth and rough endoplasmic reticulum, Golgi bodies, dense bodies and dense-cored vesicles were enhanced. The latter changes are interpreted as indications of increased synthetic activity by the superficial pineal gland in response to light deprivation.