Stefan Waliszewski - Academia.edu (original) (raw)

Papers by Stefan Waliszewski

Research paper thumbnail of Niveles de plaguicidas organoclorados en carne y grasa de bovino procedentes de veracruz, México

Revista Internacional …, 1996

RESUMEN Durante 1994 se colectaroii un total de 2 18 muestras de tejido adiposo de diversas regio... more RESUMEN Durante 1994 se colectaroii un total de 2 18 muestras de tejido adiposo de diversas regiones aiiatviiiicas y 165 muestras de distintas visceras y rnúsculos de bovinos sacrificados en el rastro municipal de la ciudad de Veracriiz que se analizaron por ...

Research paper thumbnail of Organochlorine Pesticide Levels in Maternal Adipose Tissue, Maternal Blood Serum, Umbilical Blood Serum, and Milk from Inhabitants of Veracruz, Mexico

Archives of Environmental Contamination and Toxicology, 2001

Organochlorine pesticides, due to their persistence, accumulate in food chains and cause elevated... more Organochlorine pesticides, due to their persistence, accumulate in food chains and cause elevated contamination in human beings. These residues bioconcentrate in lipid-rich tissues according to the equilibrium pattern of internal transport and lipid tissue content. The analyses of maternal adipose tissue, maternal blood serum, umbilical blood serum, colostrum, and mature milk indicate circulation of these compounds through all compartments of the maternal body, including their crossover of the placental barrier. The greatest residue levels found correspond to DDTs, with highest levels determined in colostrum (5.71 mg/kg of DDT total), followed by adipose tissue with 5.66 mg/kg and in mature milk with 4.70 mg/kg. Among DDTs, pp'DDE is the most predominant compound. The paired analyses of organochlorine pesticide residue levels between mother blood serum and umbilical blood serum demonstrate significant correlation and their transfer from mother to fetus through the placenta. The paired analyses of adipose tissue and colostrum and mature milk contamination levels indicate a high degree of coherence, principally of DDT, in the body and lactation as a decontamination means. Materials and Methods Adipose tissue, blood serum, and umbilical blood serum samples from 60 volunteer mothers were obtained from patients admitted to IMSS Hospital "Benito Coquet Lagunes" for cesarean delivery. The volunteers (18-44 years old; mean 28 years and parity one to three deliv

Research paper thumbnail of Organochlorine Pesticide Levels in Blood Serum Samples Taken at Autopsy from Auto Accident Victims in Veracruz, Mexico

Archives of Environmental Health: An International Journal, 2004

Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels we... more Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels were obtained at autopsy from auto accident victims in Veracruz, Mexico, during the years 2000 and 2001. The presence of hexachlorobenzene (HCH), beta-hexachlorocyclohexane (beta-HCH), 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT), and o,p'-DDT was confirmed by gas-liquid-electron-capture detection chromatography. During the years 2000 and 2001, the respective mean levels of (a) HCB, (b) beta-HCH, (c) p,p'-DDE, (d) o,p'-DDT, (e) p,p'-DDT, and (f) total DDT were (a) 2.1 ng/ml and 1.4 ng/ml, (b) 3.0 ng/ml and 3.6 ng/ml, (c) 21.1 ng/ml and 23.8 ng/ml, (d) 1.2 ng/ml and 0.8 ng/ml, (e) 3.3 ng/ml and 2.5 ng/ml, and, finally, (f) 25.4 ng/ml and 27.1 ng/ml, respectively. High levels of persistent organochlorine pesticides were--and continue to be--present in the blood of individuals who live in Mexico. Levels of insecticide metabolites (e.g., beta-HCH, p,p'-DDE) in blood have increased during recent years (1997-2001), but levels of p,p'-DDT decreased in 2001 because the use of DDT for the control of malaria in Mexico was restricted.

Research paper thumbnail of Chlorinated Pesticide Residues in Testicular Tissue Samples Pesticides in human testicles

Andrologia, 2009

* FlorisilB is a highly selective absorbent which has found extensive use in preparative and anal... more * FlorisilB is a highly selective absorbent which has found extensive use in preparative and analytical chromatography (FLUKA AG, Chemische Fabrik, CH-9470 Buchs/Switzerland).

Research paper thumbnail of GC determination of dichlofluanid (Eurapen) residues and its metabolite dimethylphenylsulfamide (DMSA) in strawberries

Fresenius Zeitschrift Fur Analytische Chemie, 1988

Research paper thumbnail of Use of sulfuric acid for organochlorine pesticides determination: I. Analytical quality of fat precipitated by concentrated sulfuric acid in samples with high lipid content

Revista Internacional De Contaminacion Ambiental, Mar 1, 2008

Research paper thumbnail of Gc-Bestimmung von Acephat, Methamidophos und Terbufos in Tabak

Research paper thumbnail of Low cost monitoring method for organophosphom and carbamate pesticide residues determination

Revista Internacional De Contaminacion Ambiental, 1997

Research paper thumbnail of Uso del ácido sulfúrico en las determinaaciones de plaguicidas organoclorados

Revista Internacional De Contaminacion Ambiental, 2004

Research paper thumbnail of Comparación de niveles de plaguicidas organoclorados en tejido adiposo humano entre Veracruz, Puebla y Tabasco

Research paper thumbnail of Cytogenetic biomonitoring of occupationally exposed workers to ashes from burning of sugar cane in Ahome, Sinaloa, México

Environmental Toxicology and Pharmacology, 2015

Burning the sugar cane field before harvesting has a negative impact on both air and human health... more Burning the sugar cane field before harvesting has a negative impact on both air and human health, however this issue had not been explored in Mexico. The objective of this work was to determine the chromosomal damage in workers from sugar cane burning fields in Sinaloa, México. To this purpose, we analyzed 1000 cells of buccal exfoliated epithelia from 60 exposed workers and 60 non-exposed controls to determine micronucleus frequencies and other nuclear abnormalities. The results indicated significant higher values of micronucleus and nuclear abnormalities such as binucleate cells, pyknosis, karyolysis, chromatin condensation and nuclear buds frequencies in the exposed subjects compared to those that were not exposed. Our data indicates that sugar cane burning, that generates polycyclic aromatic hydrocarbons, represents a genotoxic risk for workers in this important sugar cane producing area in Mexico.

Research paper thumbnail of Glutamate-Dependent BMAL1 Regulation in Cultured Bergmann Glia Cells

Neurochemical Research, 2015

Glutamate, the major excitatory amino acid, activates a wide variety of signal transduction casca... more Glutamate, the major excitatory amino acid, activates a wide variety of signal transduction cascades. This neurotransmitter is involved in photic entrainment of circadian rhythms, which regulate physiological and behavioral functions. The circadian clock in vertebrates is based on a transcription-translation feedback loop in which Brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like protein 1 (BMAL1) acts as transcriptional activator of others clock genes. This protein is expressed in nearly all suprachiasmatic nucleus neurons, as well as in the granular layer of the cerebellum. In this context, we decided to investigate the role of glutamate in the molecular mechanisms involved in the processes of transcription/translation of BMAL1 protein. To this end, primary cultures of chick cerebellar Bergmann glial cells were stimulated with glutamatergic ligands and we found that BMAL1 levels increased in a dose- and time dependent manner. Additionally, we studied the phosphorylation of serine residues in BMAL1 under glutamate stimulation and we were able to detect an increase in the phosphorylation of this protein. The increased expression of BMAL1 is most probably the result of a stabilization of the protein after it has been phosphorylated by the cyclic AMP-dependent protein kinase and/or the Ca(2+)/diacylglycerol dependent protein kinase. The present results strongly suggest that glutamate participates in regulating BMAL1 in glial cells and that these cells might prove to be important in the control of circadian rhythms in the cerebellum.

Research paper thumbnail of Organochlorine Pesticide Level Differences Among Female Inhabitants from Veracruz, Puebla and Tabasco, Mexico

Bulletin of Environmental Contamination and Toxicology, 2014

Organochlorine pesticides have been used in Mexico in malaria control programs and against ectopa... more Organochlorine pesticides have been used in Mexico in malaria control programs and against ectoparasites. The objective of this study was to compare the levels of organochlorine pesticides: HCB, a-b-c-HCH, pp 0-DDE, op 0-DDT and pp 0-DDT in adipose tissue of female inhabitants from three Mexican states: Veracruz, Puebla and Tabasco. Data analyses indicated higher b-HCH levels in Puebla inhabitants. When comparing the mean values of the pp 0-DDE concentrations among the three states, no statistically significant differences were noted. A trend of increasing concentrations of op 0-DDT from Veracruz to Puebla and Tabasco was observed. Significantly higher pp 0-DDT concentrations in Veracruz as compared to Puebla and Tabasco were determined. Using factorial analysis of three age categories ([30, 31-50, \51) organochlorine pesticide concentrations increases with age of participants, indicating time of exposure as a principal factor of organochlorine pesticides accumulation in adipose tissue.

Research paper thumbnail of The Consumption of Hibiscus sabdariffa Dried Calyx Ethanolic Extract Reduced Lipid Profile in Rats

Plant Foods for Human Nutrition, 2005

The scientific basis for the statement that plants and their active constituents play an importan... more The scientific basis for the statement that plants and their active constituents play an important role in the prevention of chronic and degenerative diseases is continously advancing. The object of the present study was to evaluate the effect of Hibiscus sabdariffa L. dried calyx ethanolic extract on the serum lipid profile of Sprague-Dawley rats. The rats were fed during 4 weeks with either a basal diet, containing high cholesterol (1%), cholic acid (0.25%), lard oil (10%), or a supplemental diet with H. sabdariffa extract at 5%, 10%, and 15% levels (SD 5 , SD 10 , SD 15). Weight gain and faeces dry weight were both very significantly less (p ≤ 0.01) in SD 10 and SD 15 groups as compared to the control group, as was food efficiency in SD 15. In the case of SD 10 , food efficiency was only significantly lower (p ≤ 0.05). Faeces dry weight in SD 5 however, was the only one found to be significantly higher (p ≤ 0.05). Triacylglycerols and LDL levels were both significantly less (p ≤ 0.05) in all groups (SD 5 , SD 10 , and SD 15) as compared to the control. For total lipids, SD 10 and SD 15 showed significantly lower levels (p ≤ 0.05), whereas very significant differences (p ≤ 0.01) were observed in the case of SD 5. All groups had lower cholesterol levels compared to controls; however, only the SD 5 group was statistically significant (p ≤ 0.05). No significant results were found in any group in the cases of either phospholipid or HDL levels. A hypothesis of hibiscus acid racemization, (+)-HCA to (−)-HCA, mediated by intestinal flora enzymes possibly explains the significant triacylglycerol decrease in all experimental groups. VLDL, the precursor of LDL, is composed predominantly of triacylglycerols, suggesting that the significant decrease in LDL is related to observed triacylglycerol synthesis inhibition. Five percent H. sabdariffa extract addition showed the best results in the reduction of serum lipids under study conditions.

Research paper thumbnail of Promutagen activation of triazine herbicides metribuzin and ametryn through Vicia faba metabolism inducing sister chromatid exchanges in human lymphocytes in vitro and in V. faba root tip meristems

Toxicology in Vitro, 2005

The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes i... more The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes in vitro and in root tip meristems of Vicia faba to evaluate the genotoxic effects of metribuzin and ametryn. Direct treatments of these herbicides on human lymphocytes in vitro applied 24 h after the beginning of culture did not induce SCE; however, they showed a cytotoxic effect in the cultures expressed as cellular death. On the contrary, when extracts of V. faba roots, treated for 4 h with metribuzin and ametryn (in vivo activation), were added to the lymphocyte cultures, SCEs were significantly induced with an asymptotic response. Negative responses appeared with the in vitro assays, in which metribuzin and ametryn were added directly to the 48 h lymphocyte cultures for 4 h. Nevertheless, in treatments in which the S10 metabolic mix was added, the SCE frequencies were significantly different to the control, although a concentrationresponse relationship was only observed with metribuzin. The results showed that both herbicides needed the V. faba metabolism to produce SCE in human lymphocyte cultures. Metribuzin and ametryn applied to V. faba root tip meristems for 4 h increased SCE frequency significantly, and a concentration-response relationship was observed with both herbicides.

Research paper thumbnail of A rapid and low cost monitoring method for fluvalinate determination in honey

Journal of the Science of Food and Agriculture, 1998

Abstract A simple analytical method for determining Fluvalinate residues in honey is described. A... more Abstract A simple analytical method for determining Fluvalinate residues in honey is described. Analyses were carried out by gas chromatography–electron capture detector (ECD), using a borosilicate glass column packed with 3% SP-2100. Fluvalinate residues ...

Research paper thumbnail of Circadian Nursing Induces PER1 Protein in Neuroendocrine Tyrosine Hydroxylase Neurones in the Rabbit Doe

Journal of Neuroendocrinology, 2011

Lactation in the rabbit is circadian. Behavioural studies conducted in the wild and under laborat... more Lactation in the rabbit is circadian. Behavioural studies conducted in the wild and under laboratory conditions confirm that rabbits nurse their pups just one time every day for < 5 min, with circadian periodicity (1,2). At the molecular level, circadian rhythms are produced by a positive and negative transcriptional ⁄ translational autoregulatory feedback loop. The proteins CLOCK and BMAL provide the positive transcriptional drive, whereas the proteins PERIOD (PER) 1, 2 and 3 and CRY1 and CRY2 provide the negative feedback (3). PER1 has a circadian expression in the suprachiasmatic nucleus (SCN), the master circadian clock, in several species such as mice (3), rats (4), hamsters (5) and rabbits (6). In the rabbit, maximum expression of PER1 is in the afternoon under light ⁄ dark conditions in intact nonpregnant, nonlactating females (6). Furthermore, several brain regions other than the SCN express circadian rhythms of clock genes. These include the olfactory bulb, hippocampus, cerebral cortex, pituitary gland, and arcuate, retrochiasmatic, supraoptic and paraventricular nuclei in the hypothalamus (7-10). However, both their neurochemical phenotype and functional significance remain mostly unexplored. The rabbit offers an excellent opportunity to explore the physiological significance of clock gene rhythms in neuroendocrine cells, considering the particular circadian lactation of this species (11). Accordingly, we previously reported that brief daily nursing entrains oxytocinergic (OT) neurones in the hypothalamus, as indicated by the expression of the PER1 protein, a product of the Per1 clock gene. PER1 in the SCN does not change with the physiological condition of the doe but, in contrast, brief daily nursing shifts PER1 protein rhythm in OT neurones, which peaks 4-8 h after the timing

Research paper thumbnail of Inexpensive, precise method for the determination of chlorinated pesticide residues in soil

Journal of Chromatography A, 1985

Research paper thumbnail of Organochlorine Pesticide Residues in Human Blood Serum of Inhabitants of Veracruz, Mexico

Bulletin of Environmental Contamination and Toxicology, 1999

... Blood samples were obtained during the period of October 1997 to June 1998 from sixty-five vo... more ... Blood samples were obtained during the period of October 1997 to June 1998 from sixty-five volunteer mothers admitted to IMSS ... Waliszewski SM, Pardio VTS, Chantiri JNP, Infanzón RMR,Rivera J (1996) Organochlorine pesticide residues in adipose tissue of Mexicans. ...

Research paper thumbnail of DDT and Its Metabolites in Human Milk Collected in Veracruz City and Suburban Areas (Mexico)

Bulletin of Environmental Contamination and Toxicology, 1998

... milk daily intake of 0.8 L (Cisneros and Flores 1995), a breast milk from Mexican mothers wit... more ... milk daily intake of 0.8 L (Cisneros and Flores 1995), a breast milk from Mexican mothers with a mean fat content of 3.5% (Stafford et al. 1994), and considering the Σ-DDT mean level of each group of mothers according to place of residence, the Estimated Daily Intake (EDI) of Σ ...

Research paper thumbnail of Niveles de plaguicidas organoclorados en carne y grasa de bovino procedentes de veracruz, México

Revista Internacional …, 1996

RESUMEN Durante 1994 se colectaroii un total de 2 18 muestras de tejido adiposo de diversas regio... more RESUMEN Durante 1994 se colectaroii un total de 2 18 muestras de tejido adiposo de diversas regiones aiiatviiiicas y 165 muestras de distintas visceras y rnúsculos de bovinos sacrificados en el rastro municipal de la ciudad de Veracriiz que se analizaron por ...

Research paper thumbnail of Organochlorine Pesticide Levels in Maternal Adipose Tissue, Maternal Blood Serum, Umbilical Blood Serum, and Milk from Inhabitants of Veracruz, Mexico

Archives of Environmental Contamination and Toxicology, 2001

Organochlorine pesticides, due to their persistence, accumulate in food chains and cause elevated... more Organochlorine pesticides, due to their persistence, accumulate in food chains and cause elevated contamination in human beings. These residues bioconcentrate in lipid-rich tissues according to the equilibrium pattern of internal transport and lipid tissue content. The analyses of maternal adipose tissue, maternal blood serum, umbilical blood serum, colostrum, and mature milk indicate circulation of these compounds through all compartments of the maternal body, including their crossover of the placental barrier. The greatest residue levels found correspond to DDTs, with highest levels determined in colostrum (5.71 mg/kg of DDT total), followed by adipose tissue with 5.66 mg/kg and in mature milk with 4.70 mg/kg. Among DDTs, pp'DDE is the most predominant compound. The paired analyses of organochlorine pesticide residue levels between mother blood serum and umbilical blood serum demonstrate significant correlation and their transfer from mother to fetus through the placenta. The paired analyses of adipose tissue and colostrum and mature milk contamination levels indicate a high degree of coherence, principally of DDT, in the body and lactation as a decontamination means. Materials and Methods Adipose tissue, blood serum, and umbilical blood serum samples from 60 volunteer mothers were obtained from patients admitted to IMSS Hospital "Benito Coquet Lagunes" for cesarean delivery. The volunteers (18-44 years old; mean 28 years and parity one to three deliv

Research paper thumbnail of Organochlorine Pesticide Levels in Blood Serum Samples Taken at Autopsy from Auto Accident Victims in Veracruz, Mexico

Archives of Environmental Health: An International Journal, 2004

Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels we... more Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels were obtained at autopsy from auto accident victims in Veracruz, Mexico, during the years 2000 and 2001. The presence of hexachlorobenzene (HCH), beta-hexachlorocyclohexane (beta-HCH), 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDE), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDT), and o,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDT was confirmed by gas-liquid-electron-capture detection chromatography. During the years 2000 and 2001, the respective mean levels of (a) HCB, (b) beta-HCH, (c) p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDE, (d) o,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDT, (e) p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDT, and (f) total DDT were (a) 2.1 ng/ml and 1.4 ng/ml, (b) 3.0 ng/ml and 3.6 ng/ml, (c) 21.1 ng/ml and 23.8 ng/ml, (d) 1.2 ng/ml and 0.8 ng/ml, (e) 3.3 ng/ml and 2.5 ng/ml, and, finally, (f) 25.4 ng/ml and 27.1 ng/ml, respectively. High levels of persistent organochlorine pesticides were--and continue to be--present in the blood of individuals who live in Mexico. Levels of insecticide metabolites (e.g., beta-HCH, p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDE) in blood have increased during recent years (1997-2001), but levels of p,p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-DDT decreased in 2001 because the use of DDT for the control of malaria in Mexico was restricted.

Research paper thumbnail of Chlorinated Pesticide Residues in Testicular Tissue Samples Pesticides in human testicles

Andrologia, 2009

* FlorisilB is a highly selective absorbent which has found extensive use in preparative and anal... more * FlorisilB is a highly selective absorbent which has found extensive use in preparative and analytical chromatography (FLUKA AG, Chemische Fabrik, CH-9470 Buchs/Switzerland).

Research paper thumbnail of GC determination of dichlofluanid (Eurapen) residues and its metabolite dimethylphenylsulfamide (DMSA) in strawberries

Fresenius Zeitschrift Fur Analytische Chemie, 1988

Research paper thumbnail of Use of sulfuric acid for organochlorine pesticides determination: I. Analytical quality of fat precipitated by concentrated sulfuric acid in samples with high lipid content

Revista Internacional De Contaminacion Ambiental, Mar 1, 2008

Research paper thumbnail of Gc-Bestimmung von Acephat, Methamidophos und Terbufos in Tabak

Research paper thumbnail of Low cost monitoring method for organophosphom and carbamate pesticide residues determination

Revista Internacional De Contaminacion Ambiental, 1997

Research paper thumbnail of Uso del ácido sulfúrico en las determinaaciones de plaguicidas organoclorados

Revista Internacional De Contaminacion Ambiental, 2004

Research paper thumbnail of Comparación de niveles de plaguicidas organoclorados en tejido adiposo humano entre Veracruz, Puebla y Tabasco

Research paper thumbnail of Cytogenetic biomonitoring of occupationally exposed workers to ashes from burning of sugar cane in Ahome, Sinaloa, México

Environmental Toxicology and Pharmacology, 2015

Burning the sugar cane field before harvesting has a negative impact on both air and human health... more Burning the sugar cane field before harvesting has a negative impact on both air and human health, however this issue had not been explored in Mexico. The objective of this work was to determine the chromosomal damage in workers from sugar cane burning fields in Sinaloa, México. To this purpose, we analyzed 1000 cells of buccal exfoliated epithelia from 60 exposed workers and 60 non-exposed controls to determine micronucleus frequencies and other nuclear abnormalities. The results indicated significant higher values of micronucleus and nuclear abnormalities such as binucleate cells, pyknosis, karyolysis, chromatin condensation and nuclear buds frequencies in the exposed subjects compared to those that were not exposed. Our data indicates that sugar cane burning, that generates polycyclic aromatic hydrocarbons, represents a genotoxic risk for workers in this important sugar cane producing area in Mexico.

Research paper thumbnail of Glutamate-Dependent BMAL1 Regulation in Cultured Bergmann Glia Cells

Neurochemical Research, 2015

Glutamate, the major excitatory amino acid, activates a wide variety of signal transduction casca... more Glutamate, the major excitatory amino acid, activates a wide variety of signal transduction cascades. This neurotransmitter is involved in photic entrainment of circadian rhythms, which regulate physiological and behavioral functions. The circadian clock in vertebrates is based on a transcription-translation feedback loop in which Brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like protein 1 (BMAL1) acts as transcriptional activator of others clock genes. This protein is expressed in nearly all suprachiasmatic nucleus neurons, as well as in the granular layer of the cerebellum. In this context, we decided to investigate the role of glutamate in the molecular mechanisms involved in the processes of transcription/translation of BMAL1 protein. To this end, primary cultures of chick cerebellar Bergmann glial cells were stimulated with glutamatergic ligands and we found that BMAL1 levels increased in a dose- and time dependent manner. Additionally, we studied the phosphorylation of serine residues in BMAL1 under glutamate stimulation and we were able to detect an increase in the phosphorylation of this protein. The increased expression of BMAL1 is most probably the result of a stabilization of the protein after it has been phosphorylated by the cyclic AMP-dependent protein kinase and/or the Ca(2+)/diacylglycerol dependent protein kinase. The present results strongly suggest that glutamate participates in regulating BMAL1 in glial cells and that these cells might prove to be important in the control of circadian rhythms in the cerebellum.

Research paper thumbnail of Organochlorine Pesticide Level Differences Among Female Inhabitants from Veracruz, Puebla and Tabasco, Mexico

Bulletin of Environmental Contamination and Toxicology, 2014

Organochlorine pesticides have been used in Mexico in malaria control programs and against ectopa... more Organochlorine pesticides have been used in Mexico in malaria control programs and against ectoparasites. The objective of this study was to compare the levels of organochlorine pesticides: HCB, a-b-c-HCH, pp 0-DDE, op 0-DDT and pp 0-DDT in adipose tissue of female inhabitants from three Mexican states: Veracruz, Puebla and Tabasco. Data analyses indicated higher b-HCH levels in Puebla inhabitants. When comparing the mean values of the pp 0-DDE concentrations among the three states, no statistically significant differences were noted. A trend of increasing concentrations of op 0-DDT from Veracruz to Puebla and Tabasco was observed. Significantly higher pp 0-DDT concentrations in Veracruz as compared to Puebla and Tabasco were determined. Using factorial analysis of three age categories ([30, 31-50, \51) organochlorine pesticide concentrations increases with age of participants, indicating time of exposure as a principal factor of organochlorine pesticides accumulation in adipose tissue.

Research paper thumbnail of The Consumption of Hibiscus sabdariffa Dried Calyx Ethanolic Extract Reduced Lipid Profile in Rats

Plant Foods for Human Nutrition, 2005

The scientific basis for the statement that plants and their active constituents play an importan... more The scientific basis for the statement that plants and their active constituents play an important role in the prevention of chronic and degenerative diseases is continously advancing. The object of the present study was to evaluate the effect of Hibiscus sabdariffa L. dried calyx ethanolic extract on the serum lipid profile of Sprague-Dawley rats. The rats were fed during 4 weeks with either a basal diet, containing high cholesterol (1%), cholic acid (0.25%), lard oil (10%), or a supplemental diet with H. sabdariffa extract at 5%, 10%, and 15% levels (SD 5 , SD 10 , SD 15). Weight gain and faeces dry weight were both very significantly less (p ≤ 0.01) in SD 10 and SD 15 groups as compared to the control group, as was food efficiency in SD 15. In the case of SD 10 , food efficiency was only significantly lower (p ≤ 0.05). Faeces dry weight in SD 5 however, was the only one found to be significantly higher (p ≤ 0.05). Triacylglycerols and LDL levels were both significantly less (p ≤ 0.05) in all groups (SD 5 , SD 10 , and SD 15) as compared to the control. For total lipids, SD 10 and SD 15 showed significantly lower levels (p ≤ 0.05), whereas very significant differences (p ≤ 0.01) were observed in the case of SD 5. All groups had lower cholesterol levels compared to controls; however, only the SD 5 group was statistically significant (p ≤ 0.05). No significant results were found in any group in the cases of either phospholipid or HDL levels. A hypothesis of hibiscus acid racemization, (+)-HCA to (−)-HCA, mediated by intestinal flora enzymes possibly explains the significant triacylglycerol decrease in all experimental groups. VLDL, the precursor of LDL, is composed predominantly of triacylglycerols, suggesting that the significant decrease in LDL is related to observed triacylglycerol synthesis inhibition. Five percent H. sabdariffa extract addition showed the best results in the reduction of serum lipids under study conditions.

Research paper thumbnail of Promutagen activation of triazine herbicides metribuzin and ametryn through Vicia faba metabolism inducing sister chromatid exchanges in human lymphocytes in vitro and in V. faba root tip meristems

Toxicology in Vitro, 2005

The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes i... more The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes in vitro and in root tip meristems of Vicia faba to evaluate the genotoxic effects of metribuzin and ametryn. Direct treatments of these herbicides on human lymphocytes in vitro applied 24 h after the beginning of culture did not induce SCE; however, they showed a cytotoxic effect in the cultures expressed as cellular death. On the contrary, when extracts of V. faba roots, treated for 4 h with metribuzin and ametryn (in vivo activation), were added to the lymphocyte cultures, SCEs were significantly induced with an asymptotic response. Negative responses appeared with the in vitro assays, in which metribuzin and ametryn were added directly to the 48 h lymphocyte cultures for 4 h. Nevertheless, in treatments in which the S10 metabolic mix was added, the SCE frequencies were significantly different to the control, although a concentrationresponse relationship was only observed with metribuzin. The results showed that both herbicides needed the V. faba metabolism to produce SCE in human lymphocyte cultures. Metribuzin and ametryn applied to V. faba root tip meristems for 4 h increased SCE frequency significantly, and a concentration-response relationship was observed with both herbicides.

Research paper thumbnail of A rapid and low cost monitoring method for fluvalinate determination in honey

Journal of the Science of Food and Agriculture, 1998

Abstract A simple analytical method for determining Fluvalinate residues in honey is described. A... more Abstract A simple analytical method for determining Fluvalinate residues in honey is described. Analyses were carried out by gas chromatography–electron capture detector (ECD), using a borosilicate glass column packed with 3% SP-2100. Fluvalinate residues ...

Research paper thumbnail of Circadian Nursing Induces PER1 Protein in Neuroendocrine Tyrosine Hydroxylase Neurones in the Rabbit Doe

Journal of Neuroendocrinology, 2011

Lactation in the rabbit is circadian. Behavioural studies conducted in the wild and under laborat... more Lactation in the rabbit is circadian. Behavioural studies conducted in the wild and under laboratory conditions confirm that rabbits nurse their pups just one time every day for < 5 min, with circadian periodicity (1,2). At the molecular level, circadian rhythms are produced by a positive and negative transcriptional ⁄ translational autoregulatory feedback loop. The proteins CLOCK and BMAL provide the positive transcriptional drive, whereas the proteins PERIOD (PER) 1, 2 and 3 and CRY1 and CRY2 provide the negative feedback (3). PER1 has a circadian expression in the suprachiasmatic nucleus (SCN), the master circadian clock, in several species such as mice (3), rats (4), hamsters (5) and rabbits (6). In the rabbit, maximum expression of PER1 is in the afternoon under light ⁄ dark conditions in intact nonpregnant, nonlactating females (6). Furthermore, several brain regions other than the SCN express circadian rhythms of clock genes. These include the olfactory bulb, hippocampus, cerebral cortex, pituitary gland, and arcuate, retrochiasmatic, supraoptic and paraventricular nuclei in the hypothalamus (7-10). However, both their neurochemical phenotype and functional significance remain mostly unexplored. The rabbit offers an excellent opportunity to explore the physiological significance of clock gene rhythms in neuroendocrine cells, considering the particular circadian lactation of this species (11). Accordingly, we previously reported that brief daily nursing entrains oxytocinergic (OT) neurones in the hypothalamus, as indicated by the expression of the PER1 protein, a product of the Per1 clock gene. PER1 in the SCN does not change with the physiological condition of the doe but, in contrast, brief daily nursing shifts PER1 protein rhythm in OT neurones, which peaks 4-8 h after the timing

Research paper thumbnail of Inexpensive, precise method for the determination of chlorinated pesticide residues in soil

Journal of Chromatography A, 1985

Research paper thumbnail of Organochlorine Pesticide Residues in Human Blood Serum of Inhabitants of Veracruz, Mexico

Bulletin of Environmental Contamination and Toxicology, 1999

... Blood samples were obtained during the period of October 1997 to June 1998 from sixty-five vo... more ... Blood samples were obtained during the period of October 1997 to June 1998 from sixty-five volunteer mothers admitted to IMSS ... Waliszewski SM, Pardio VTS, Chantiri JNP, Infanzón RMR,Rivera J (1996) Organochlorine pesticide residues in adipose tissue of Mexicans. ...

Research paper thumbnail of DDT and Its Metabolites in Human Milk Collected in Veracruz City and Suburban Areas (Mexico)

Bulletin of Environmental Contamination and Toxicology, 1998

... milk daily intake of 0.8 L (Cisneros and Flores 1995), a breast milk from Mexican mothers wit... more ... milk daily intake of 0.8 L (Cisneros and Flores 1995), a breast milk from Mexican mothers with a mean fat content of 3.5% (Stafford et al. 1994), and considering the Σ-DDT mean level of each group of mothers according to place of residence, the Estimated Daily Intake (EDI) of Σ ...