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Papers by Jorge Garcia-Tamayo
PubMed, Nov 1, 1978
The fine structure of Trichomonas vaginalis and its acid phosphatase activity in the vaginal medi... more The fine structure of Trichomonas vaginalis and its acid phosphatase activity in the vaginal medium was investigated with the aid of the electron microscope. The relationship among trichomonads, desquamated epithelial cells, macrophages and bacteria was examined with special attention directed towards their phagocytic behavior. Acid phosphatase activity was observed in the Golgi apparatus, phagolysosomes and in the chromatic granules of Trichomonas vaginalis. Macrophages and leukocytes also exhibited activity for acid phosphatase, particularly during phagocytosis. Phagocytosis and digestion of epithelial cells and bacteria by trichomonads was demonstrated. The study of trichomonads in the vaginal medium is considered to be an important approach towards the understanding of the pathogenesis of lesions induced by this parasite.
PubMed, 1992
Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects o... more Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental vessels, vascular changes in the central nervous system were also described in rats surviving Venezuelan Equine Encephalitis experimental infection; similar changes were described in the brain of children with post rubella syndrome. The need for multidisciplinary studies in the endemic areas of Venezuelan Equine Encephalitis in order to detect sequelae of the viral effects in utero is emphasized. Finally, some experimental animal models are proposed to examine diverse aspects on intrauterine effect of Venezuelan Equine Encephalitis virus.
PubMed, May 1, 1989
Inclusion bodies were previously found in Papanicolaou smears of patients infected by the human p... more Inclusion bodies were previously found in Papanicolaou smears of patients infected by the human papillomavirus (HPV). To ascertain their origin, 12 biopsies from patients with colposcopic evidence of papillomatous lesions were studied by cytology and electron microscopy. In several instances, koilocytotic atypias and electron-dense masses included within epithelial cells were observed. Some of these epithelial cells appeared to be surrounded by other cells in a sort of concentric arrangement. The electron-dense masses were composed of intermediate filaments, vacuoles and electron-dense material. They seemed to be dyskeratotic cells. They can be compared with apoptotic bodies and may be related to a disturbance of the involucrin expression caused by the HPV infection.
PubMed, 1982
Exudates from the vagina and uterine cervix of ten patients suffering from genital candidiasis (C... more Exudates from the vagina and uterine cervix of ten patients suffering from genital candidiasis (Candida albicans) were studied with transmission and scanning electron microscopy and with histochemical techniques in order to find the precise location of the Candida infection and to examine the relationship between the vaginal and cervical cells and the infecting yeasts. It was found that Candida species can penetrate, invade, develop and proliferate within the deep layers of intact cells of the cervix and vaginal mucosal epithelium. The presence of mucopolysaccharides in the glycoproteinaceous coat of blastospores and pseudohyphae was demonstrated both outside and within squamous epithelial cells. The importance of the integrity of the glycoprotein coat during the pathogenesis of human infection with C. albicans is therefore emphasized. Furthermore, the histoinvasive yeast apparently produced cytolytic enzymes during its growth within the human vaginal and cervical mucosal epithelium. The intracellular growth of Candida organisms may represent a protective mechanism of the fungus against the host and a manner of resistance to antimycotic therapy.
PubMed, Mar 1, 1996
Although some types of intestinal metaplasia are considered to be potentially pre-malignant lesio... more Although some types of intestinal metaplasia are considered to be potentially pre-malignant lesions leading to gastric carcinoma, their high frequency and variability limit their usefulness as early markers of malignant progression. The present study was carried out to search for parameters which could be used in conjunction with histological diagnosis to identify groups of patients with a high risk for developing gastric neoplasia. The expression of proliferating cell nuclear antigen (PCNA), as revealed by immunohistochemical staining of anti-PCNA monoclonal antibody (PC10) in 82 endoscopic biopsy specimens, was compared with the histological classification of intestinal metaplasia, the biochemical composition of gastric mucins and the expression of blood group Lewis antigens. Statistically significant (p 0.001) correlation between the PCNA labelling index (the percentage of positive cells in more than 700 tumor cells per sample) and the histological type of intestinal metaplasia, the presence of sulphomucins, and the presence of anomalous Lewis a antigen was found. We conclude that a high PCNA-labelling index in the gastric mucosa, with a histological diagnosis of incomplete intestinal metaplasia, could constitute a good prognostic marker of the severity of the histologic lesion. These parameters, together with others such as the presence of sulphomucins and of cells expressing anomalous Lewis a antigen, may be used to define patients with a high risk of developing a gastric neoplasia.
![Research paper thumbnail of [Importance of immunohistochemical studies in the diagnosis and the prognostic evaluation of cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix. Review]](https://attachments.academia-assets.com/110592242/thumbnails/1.jpg)
](Investigación clínica, 2009
Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are eval... more Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are evaluated in this review. A variety of proteins like p53, bcl2, C-Myc, Ki 67, Cyclines, P16 INK4a, p21, p27, beta-catenin, Wnt and MCM, have been related to the development of cervical neoplasia and human papilloma virus infection. It is described how transcriptional factors of genes induce loss of heterozygosity, numerical chromosome abnormality and inactivation of gene products or the partial loss of some membrane glycoproteins induced by oncogenic human papillomaviruses (HPV).
Dieciocho casos de tumores metastáticos en los ovarios fueron examinados por inmunohistoquímica p... more Dieciocho casos de tumores metastáticos en los ovarios fueron examinados por inmunohistoquímica para analizar la importancia de esta técnica en precisar el diagnóstico y decidir el tratamiento de los mismos. El estudio inmunohistoquímico se hizo con diversos anticuerpos específicos, seleccionados para cada caso. En un total de 18 casos de tumores metastáticos, siete casos tenían metástasis del tracto gastrointestinal, de los cuales 5 casos eran adenocarcinomas mucinosos del colon y en 2 casos de metástasis el tumor primario se suponía estaba en el estómago o el páncreas. Seis casos correspondieron a tumores ováricos primarios con metástasis al ovario contralateral y al epiplón o al peritoneo. En cinco casos, los tumores metastásicos se originaban en carcinomas de las glándulas mamarias, adenoescamoso del cervix y del endometrio. Los estudios de inmunohistoquímica para el diagnóstico de los tumores metastáticos del ovario resultan usualmente cruciales para la evaluar el pronóstico y el tratamiento de las pacientes.
Dermatología Venezolana, 1991
Clinical & Translational Oncology, Apr 1, 2008
Expression of blood group antigens in normal, displastic and tumoral uterine cervix from 35 hyste... more Expression of blood group antigens in normal, displastic and tumoral uterine cervix from 35 hysterectomised women with carcinoma of the cervix was investigated; the results were correlated with patients' ABH phenotype and secretor status. We used an indirect immunoperoxidase technique and a panel of monoclonal antibodies and lectins directed against different antigenic specificities. Anomalous expression of blood group antigens in premalignant lesions from cervix was found. Partial loos of expression of blood group antigens and some lectins in different grades of cervical intraepithelial neoplasia, and a total loss of expression in CIN III and in infiltrating carcinoma of the cervix from secretor patients was revealed. The findings herein described confirm the importance of these antigens as tumour markers and they might be useful for the study of cervical carcinogenesis.
Oral Surgery, Oral Medicine, Oral Pathology, Dec 1, 1974
Abstract The fine structure of neurosecretory cells (Merkel cells) in human gingiva is presented.... more Abstract The fine structure of neurosecretory cells (Merkel cells) in human gingiva is presented. As a characteristic feature, these cells possess dense granules which can be extruded from the cytoplasm into the intercellular space. The functional significance of the Merkel cell is discussed on the basis of modern concepts of neurosecretion and its possible role in aphthous stomatitis.
European Journal of Cancer, 1996
mens from 48 patients with superficial transitional carcinoma, with the use of the PC10 monoclona... more mens from 48 patients with superficial transitional carcinoma, with the use of the PC10 monoclonal antibody. In vesical tumours with good clinical behaviour, we found a median PCNA positivity of 7.1% with a range of 5-25%. In vesical tumours with high incidence of recurrence, the median was 36.6% with a range of 15-80%. In vesical tumours with a strong tendency to invasion, the median positivity for PCNA staining was 68% with a range of 40-92%. In conclusion, we believe that using PC10 immunostaining to determine a nuclear proliferative fraction is a quick and simple method of studying the prognosis of patients who have vesical tumours of low grade and low stage.
Investigacion Clinica, 1970
Biopsias de encia normal se sometieron a fijacion en glutoraldehido y osmio, coloracion con aceta... more Biopsias de encia normal se sometieron a fijacion en glutoraldehido y osmio, coloracion con acetato de uranilo y plomo e inclusion en cocodilato; seccion previa congelacion e incubacion en un medio que contiene betaglicerofosfato de sodio, buffer acetato y acetato de plomo; fijacion posterior en osmio, e inclusion en Araldita. Colaboracion similar a la anterior. Los pequenos granulos contenian material electrodenso en su interior; algunos estaban cruzados por laminas. Se observo la fusion de estos granulos con la membrana citoplasmatica, y el paso de su contenido al espacio intersticial. En los extremos del complejo de Golgi se observaron vesiculas que, presumiblemente, son las precursoras de los pequenos granulos. En el material incubado para histoquimica, se encontro actividad de la enzima fosfatasa acida en el interior de los pequenos granulos. La actividad de la enzima parecia extenderse sobre las laminas que tabicaban los granulos y era muy manifiesta en el espacio intersticial...
Summary. Vene~uelan equine encephalomyelitis (VEE) virus. purified in sucrose density gradients w... more Summary. Vene~uelan equine encephalomyelitis (VEE) virus. purified in sucrose density gradients was examined with the e1ectron microscope before and after sodium desoxycholate (DOC) treatment. The structure of the nucleocapsid revealedlO to 12 nm nng shaped units organized into an icosahedral symmetry. Density gradient fractions exhibiting hemagglutina ting actMty after DOC treatment show 12 to 18 nm particles lined by short projections. These isolated hemaggIutinating subunlts are though to corres pond to the superficial spikes of VEE virus.
Vitae Academia Biomedica Digital, 2010
Revista Vitae, Sep 7, 2013
PubMed, Nov 1, 1978
The fine structure of Trichomonas vaginalis and its acid phosphatase activity in the vaginal medi... more The fine structure of Trichomonas vaginalis and its acid phosphatase activity in the vaginal medium was investigated with the aid of the electron microscope. The relationship among trichomonads, desquamated epithelial cells, macrophages and bacteria was examined with special attention directed towards their phagocytic behavior. Acid phosphatase activity was observed in the Golgi apparatus, phagolysosomes and in the chromatic granules of Trichomonas vaginalis. Macrophages and leukocytes also exhibited activity for acid phosphatase, particularly during phagocytosis. Phagocytosis and digestion of epithelial cells and bacteria by trichomonads was demonstrated. The study of trichomonads in the vaginal medium is considered to be an important approach towards the understanding of the pathogenesis of lesions induced by this parasite.
PubMed, 1992
Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects o... more Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental vessels, vascular changes in the central nervous system were also described in rats surviving Venezuelan Equine Encephalitis experimental infection; similar changes were described in the brain of children with post rubella syndrome. The need for multidisciplinary studies in the endemic areas of Venezuelan Equine Encephalitis in order to detect sequelae of the viral effects in utero is emphasized. Finally, some experimental animal models are proposed to examine diverse aspects on intrauterine effect of Venezuelan Equine Encephalitis virus.
PubMed, May 1, 1989
Inclusion bodies were previously found in Papanicolaou smears of patients infected by the human p... more Inclusion bodies were previously found in Papanicolaou smears of patients infected by the human papillomavirus (HPV). To ascertain their origin, 12 biopsies from patients with colposcopic evidence of papillomatous lesions were studied by cytology and electron microscopy. In several instances, koilocytotic atypias and electron-dense masses included within epithelial cells were observed. Some of these epithelial cells appeared to be surrounded by other cells in a sort of concentric arrangement. The electron-dense masses were composed of intermediate filaments, vacuoles and electron-dense material. They seemed to be dyskeratotic cells. They can be compared with apoptotic bodies and may be related to a disturbance of the involucrin expression caused by the HPV infection.
PubMed, 1982
Exudates from the vagina and uterine cervix of ten patients suffering from genital candidiasis (C... more Exudates from the vagina and uterine cervix of ten patients suffering from genital candidiasis (Candida albicans) were studied with transmission and scanning electron microscopy and with histochemical techniques in order to find the precise location of the Candida infection and to examine the relationship between the vaginal and cervical cells and the infecting yeasts. It was found that Candida species can penetrate, invade, develop and proliferate within the deep layers of intact cells of the cervix and vaginal mucosal epithelium. The presence of mucopolysaccharides in the glycoproteinaceous coat of blastospores and pseudohyphae was demonstrated both outside and within squamous epithelial cells. The importance of the integrity of the glycoprotein coat during the pathogenesis of human infection with C. albicans is therefore emphasized. Furthermore, the histoinvasive yeast apparently produced cytolytic enzymes during its growth within the human vaginal and cervical mucosal epithelium. The intracellular growth of Candida organisms may represent a protective mechanism of the fungus against the host and a manner of resistance to antimycotic therapy.
PubMed, Mar 1, 1996
Although some types of intestinal metaplasia are considered to be potentially pre-malignant lesio... more Although some types of intestinal metaplasia are considered to be potentially pre-malignant lesions leading to gastric carcinoma, their high frequency and variability limit their usefulness as early markers of malignant progression. The present study was carried out to search for parameters which could be used in conjunction with histological diagnosis to identify groups of patients with a high risk for developing gastric neoplasia. The expression of proliferating cell nuclear antigen (PCNA), as revealed by immunohistochemical staining of anti-PCNA monoclonal antibody (PC10) in 82 endoscopic biopsy specimens, was compared with the histological classification of intestinal metaplasia, the biochemical composition of gastric mucins and the expression of blood group Lewis antigens. Statistically significant (p 0.001) correlation between the PCNA labelling index (the percentage of positive cells in more than 700 tumor cells per sample) and the histological type of intestinal metaplasia, the presence of sulphomucins, and the presence of anomalous Lewis a antigen was found. We conclude that a high PCNA-labelling index in the gastric mucosa, with a histological diagnosis of incomplete intestinal metaplasia, could constitute a good prognostic marker of the severity of the histologic lesion. These parameters, together with others such as the presence of sulphomucins and of cells expressing anomalous Lewis a antigen, may be used to define patients with a high risk of developing a gastric neoplasia.
Investigación clínica, 2009
Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are eval... more Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are evaluated in this review. A variety of proteins like p53, bcl2, C-Myc, Ki 67, Cyclines, P16 INK4a, p21, p27, beta-catenin, Wnt and MCM, have been related to the development of cervical neoplasia and human papilloma virus infection. It is described how transcriptional factors of genes induce loss of heterozygosity, numerical chromosome abnormality and inactivation of gene products or the partial loss of some membrane glycoproteins induced by oncogenic human papillomaviruses (HPV).
Dieciocho casos de tumores metastáticos en los ovarios fueron examinados por inmunohistoquímica p... more Dieciocho casos de tumores metastáticos en los ovarios fueron examinados por inmunohistoquímica para analizar la importancia de esta técnica en precisar el diagnóstico y decidir el tratamiento de los mismos. El estudio inmunohistoquímico se hizo con diversos anticuerpos específicos, seleccionados para cada caso. En un total de 18 casos de tumores metastáticos, siete casos tenían metástasis del tracto gastrointestinal, de los cuales 5 casos eran adenocarcinomas mucinosos del colon y en 2 casos de metástasis el tumor primario se suponía estaba en el estómago o el páncreas. Seis casos correspondieron a tumores ováricos primarios con metástasis al ovario contralateral y al epiplón o al peritoneo. En cinco casos, los tumores metastásicos se originaban en carcinomas de las glándulas mamarias, adenoescamoso del cervix y del endometrio. Los estudios de inmunohistoquímica para el diagnóstico de los tumores metastáticos del ovario resultan usualmente cruciales para la evaluar el pronóstico y el tratamiento de las pacientes.
Dermatología Venezolana, 1991
Clinical & Translational Oncology, Apr 1, 2008
Expression of blood group antigens in normal, displastic and tumoral uterine cervix from 35 hyste... more Expression of blood group antigens in normal, displastic and tumoral uterine cervix from 35 hysterectomised women with carcinoma of the cervix was investigated; the results were correlated with patients' ABH phenotype and secretor status. We used an indirect immunoperoxidase technique and a panel of monoclonal antibodies and lectins directed against different antigenic specificities. Anomalous expression of blood group antigens in premalignant lesions from cervix was found. Partial loos of expression of blood group antigens and some lectins in different grades of cervical intraepithelial neoplasia, and a total loss of expression in CIN III and in infiltrating carcinoma of the cervix from secretor patients was revealed. The findings herein described confirm the importance of these antigens as tumour markers and they might be useful for the study of cervical carcinogenesis.
Oral Surgery, Oral Medicine, Oral Pathology, Dec 1, 1974
Abstract The fine structure of neurosecretory cells (Merkel cells) in human gingiva is presented.... more Abstract The fine structure of neurosecretory cells (Merkel cells) in human gingiva is presented. As a characteristic feature, these cells possess dense granules which can be extruded from the cytoplasm into the intercellular space. The functional significance of the Merkel cell is discussed on the basis of modern concepts of neurosecretion and its possible role in aphthous stomatitis.
European Journal of Cancer, 1996
mens from 48 patients with superficial transitional carcinoma, with the use of the PC10 monoclona... more mens from 48 patients with superficial transitional carcinoma, with the use of the PC10 monoclonal antibody. In vesical tumours with good clinical behaviour, we found a median PCNA positivity of 7.1% with a range of 5-25%. In vesical tumours with high incidence of recurrence, the median was 36.6% with a range of 15-80%. In vesical tumours with a strong tendency to invasion, the median positivity for PCNA staining was 68% with a range of 40-92%. In conclusion, we believe that using PC10 immunostaining to determine a nuclear proliferative fraction is a quick and simple method of studying the prognosis of patients who have vesical tumours of low grade and low stage.
Investigacion Clinica, 1970
Biopsias de encia normal se sometieron a fijacion en glutoraldehido y osmio, coloracion con aceta... more Biopsias de encia normal se sometieron a fijacion en glutoraldehido y osmio, coloracion con acetato de uranilo y plomo e inclusion en cocodilato; seccion previa congelacion e incubacion en un medio que contiene betaglicerofosfato de sodio, buffer acetato y acetato de plomo; fijacion posterior en osmio, e inclusion en Araldita. Colaboracion similar a la anterior. Los pequenos granulos contenian material electrodenso en su interior; algunos estaban cruzados por laminas. Se observo la fusion de estos granulos con la membrana citoplasmatica, y el paso de su contenido al espacio intersticial. En los extremos del complejo de Golgi se observaron vesiculas que, presumiblemente, son las precursoras de los pequenos granulos. En el material incubado para histoquimica, se encontro actividad de la enzima fosfatasa acida en el interior de los pequenos granulos. La actividad de la enzima parecia extenderse sobre las laminas que tabicaban los granulos y era muy manifiesta en el espacio intersticial...
Summary. Vene~uelan equine encephalomyelitis (VEE) virus. purified in sucrose density gradients w... more Summary. Vene~uelan equine encephalomyelitis (VEE) virus. purified in sucrose density gradients was examined with the e1ectron microscope before and after sodium desoxycholate (DOC) treatment. The structure of the nucleocapsid revealedlO to 12 nm nng shaped units organized into an icosahedral symmetry. Density gradient fractions exhibiting hemagglutina ting actMty after DOC treatment show 12 to 18 nm particles lined by short projections. These isolated hemaggIutinating subunlts are though to corres pond to the superficial spikes of VEE virus.
Vitae Academia Biomedica Digital, 2010
Revista Vitae, Sep 7, 2013