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Biomedical subjects

J Villalobos

Publications and source records attributed to J Villalobos.

At least 19 recordsLinked to original sources
PubMed2001

Acetylcholinesterase and butyrylcholinesterase histochemical activities and tumor cell growth in several brain tumors.

BACKGROUND: The hydrolysis enzymes of the acetylcholine, acetylcholinesterase, and butyrylcholinesterase are involved in non-cholinergic functions such as proliferation processes and cellular adhesion. These enzymes have been found in several tumors other from brain tumors. METHODS: Thirty fresh brain tumor specimens were obtained from biopsies taken during neurosurgical procedures. The specimens were cut in two parts, one designated for routine histopathological control and the other for histochemical and growth studies. The formalin fixed specimens were serially cut at 10 microm in a freezing cryostat, mounted in gelatin-coated slides, and processed for sensitive histochemical detection of acetylcholinesterase and butyrylcholinesterase. The other specimens were processed for a HMEM cell growth culture. RESULTS: The results show the coexistence of acetylcholinesterase and butyrylcholinesterase in all tumors studied. Type II and III gliomas and oligodendrogliomas show moderate activity of both cholinesterases, whereas in type IV glioma and meningiomas the labeling of both cholinesterases was high. In the craniopharyngiomas a high acetylcholinesterase activity was observed and low level of butyrylcholinesterase labeling. The cell growth was high only in the cases in which butyrylcholinesterase activity was high, such as type IV glioma. In type II and III gliomas, oligodendroglioma, and craniopharyngioma the growth rate was slow. CONCLUSIONS: These results could indicate a possible relationship between the presence of butyrylcholinesterase and acetylcholinesterase in brain tumor tissue and cellular proliferation in tumorigenesis.

Acetylcholinesterase↗
PubMed2001

Postnatal development of cholinergic system in mouse basal forebrain: acetylcholinesterase histochemistry and choline-acetyltransferase immunoreactivity.

The distribution of acetylcholinesterase histochemistry and choline-O-acetyltransferase immunohistochemistry in the basal forebrain was studied in newborn mice (P0) and until 60 days of postnatal life (P60). A weak acetylcholinesterase activity was found at P0 and P2 in the anterior and intermediate parts of the basal forebrain, and higher in the posterior region. The intensity of labeling, neuronal size and dendritic growth seems to increase progressively in all regions of basal forebrain from P4 to P10. The AChE+ cell count shows that in the anterior portion of the magnocellular basal nucleus the number of cells does not vary significantly from birth to the second month of postnatal life. However, in the intermediate and posterior portions of the nucleus the mean number of labeled cells increases significantly from birth to the end of the second week of postnatal life (P13). The choline-acetyltransferase immunoreactivity appears only detectable at the end of the first week (P6) as a slight immunoreaction, which increases progressively in intensity at P8, and at P10 seems to attain the same intensity of labeling found at P60. These results seem to indicate that the acetylcholinesterase could have a non-classic cholinergic role in the first stages of postnatal development, acting as a growth and cellular differentiation factor.

Acetylcholinesterase↗
PubMed2000

Postnatal development of the basal forebrain cholinergic projections to the medial prefrontal cortex in mice.

The postnatal development of basal forebrain cholinergic projections to the medial prefrontal cortex in mice was analyzed by means of the double labeling track-tracing study. The tracer was injected into the medial prefrontal cortex of mice, on the day of birth (P0) to 60 days after birth. The total number of basal forebrain neurons increased from P4 to P8, and began to decrease until P13 (52.9% vs. the maximal average (P8)). After P13, the mean average remains stable up to P60. On the other hand, differential pattern of frontocortical projections of the anterior, intermediate, and posterior regions can be observed.

Acetylcholinesterase↗
PubMed1999

Mortality supposedly due to intoxication by pyrrolizidine alkaloids from Heliotropium indicum in a horse population in Costa Rica: a case report.

This article describes a case of massive mortality among horses which was probably due to intoxication by pyrrolizidine alkaloids from Heliotropium indicum. Over 4 years more than 75% of a population of about 110 horses on a farm in Costa Rica died after showing nervous neurological symptoms. Two clinical manifestations were encountered, an acute and a chronic one, both with a fatal outcome. Pathological findings in 2 horses coincided with those reported in the literature for intoxication by pyrrolizidine alkaloids and were not specific for VEE. However Venezuelan equine encephalitis (VEE) was the main differential diagnosis and could not completely be excluded because this disease was endemic in the region and VEE titres were found to be high. Taxonomic and toxicological investigations implicated Heliotropium indicum as the most probable principal cause of the intoxication.

Animal Feed↗
PubMed1998

Estimation of optimal concentration of fluoride in drinking water under conditions prevailing in Chile.

The purpose of this comparative study of caries and dental fluorosis experience in Chilean children was to estimate the optimal range of fluoride concentration in tap water under conditions currently prevailing in Chile. The sample included 2431 schoolchildren 7, 12 and 15 years old, life-long residents of five communities with fluoride concentrations in their tap water in the range 0.07-1.1 mg/L. The study population received an oral clinical examination including caries experience and an enamel fluorosis evaluation of the permanent dentition (Dean's scoring system). For 15-year-old children, the DMFT index changed from 5.06 to 2.60, and for 12-year-olds it changed from 3.10 to 1.36 when fluoride water concentration changed from 0.07 to 1.10 mg/L. For 7-year-old children the dmft index correspondingly changed from 3.67 to 1.59. The relationship between DMFT for 12-year-olds and water fluoride concentration was best fitted by a logarithmic function (r2=0.98). The Community Fluorosis Index (CFI) was used to assess enamel fluorosis in the study population, and it showed a linear relationship (r2=0.983) with increasing fluoride concentration of water for the 12-year-old group. Results obtained suggest that under current Chilean conditions, the optimal range of fluoride concentration in potable water should lie in the 0.5-0.6 mg/L range.

Adolescent↗
PubMed1998

Dental fluorosis in Chilean children: evaluation of risk factors.

The purpose of this case-control study was to determine the association between very-mild-to-moderate enamel fluorosis and exposure during early childhood to fluoridated water, mainly through ingestion of powdered milk. Analysis was performed on 136 residents of the optimally fluoridated community of San Felipe in the Chilean Fifth Region, who were categorised into one of three groups according to their age when water fluoridation was introduced in 1986: Group I was born after 1986; Group II was 16-24 months old in 1986; and Group III was >24 months of age. The case and control subjects were selected on the basis of a clinical examination given in July 1996. Dean's scoring system was used to determine fluorosis status. Risk factor exposure was ascertained by a questionnaire used in interviews with mothers of participating children. Logistic regression analysis, after adjustment for confounding variables, revealed that very-mild-to-moderate enamel fluorosis of permanent central maxillary incisors (CMI) was strongly associated both with the age of the subjects when water fluoridation began and with breast-feeding duration for children belonging to Group I. Subjects in Group I were 20.44 times more likely (95% CI: 5.00-93.48) to develop CMI fluorosis than children who were older than 24 months (Group III) when fluoridation began. Subjects who were between 16 and 24 months old when water fluoridation began were 4.15 times more likely (95% CI: 1.05-16.43) to have CMI fluorosis than children older than 24 months. An inverse association was found with breastfeeding duration (OR=0.86, 95% CI: 0.75-0.98) among Group I subjects but not in Groups II and III. Results obtained suggest that the current fluoride concentration in drinking water may be contributing to fluorosis. Further studies will be necessary to determine the relative competing risks of dental fluorosis and dental caries in Chilean children in order to establish the most appropriate water fluoridation level in Chile.

Analysis of Variance↗
PubMed1997

[Primary transitional cell carcinoma of the prostate. An infrequent tumor].

Primary prostatic carcinoma accounts for 2% to 4.5% of all neoplasias to this organ, and it has been observed in 2.8% of all radical cystoprostatectomies performed in the Mayo clinic. It originates in the poorly differentiated reservoir cells of the prostatic periurethral ductus which explains why diagnosis is most often obtained in advanced stages (stromal involvement), thus limiting its management to radical surgery. This paper contributes one case report of a patient diagnosed by transrectal biopsy of a primary prostatic transitional carcinoma presenting with incoercible rectorrahges and urinary obstruction symptoms. Treatment was through pelvic exenteration, and urinary and gut by-pass.

Biopsy↗
PubMed1994

Demonstration of peptidergic afferents to the bed nucleus of the stria terminalis using local injections of colchicine. A combined immunohistochemical and retrograde tracing study.

In the present study, we demonstrate the existence of numerous peptidergic afferents to the bed nucleus of the stria terminalis (BNST) using the retrograde transport of gold-labeled wheat germ agglutinin-apo-peroxidase (G-WGA-HRP) combined with the indirect immunoperoxidase method after intraparenchymatous injections of colchicine. At first, we show that local injections of colchicine alone into the BNST are able to induce the retrograde accumulation of peptides until the nerve cell bodies of origin, probably because of the blockade of axonal transport in nerve terminal arborizations innervating this nucleus. The actual existence of putative peptidergic afferents to the BNST indicated by the local injections of colchicine was established using: a) the retrograde transport of G-WGA-HRP from the BNST combined with immunocytochemistry after administration of colchicine at the same place, b) the anterograde "transport" of the fluorescent tracer DiI from selected nuclei of the forebrain. We demonstrate that the neurons immunoreactive for enkephalins, neurotensin, or substance P that innervate the BNST are localized mainly in the central amygdaloid nucleus, the paraventricular thalamic nucleus, and the ventromedial hypothalamic nucleus ipsilateral to the injection, as well as bilaterally in the magnocellular paraventricular and perifornical regions of the hypothalamus. From these results it may be concluded that intracerebral injections of colchicine constitute a powerful tool to search for multiple peptidergic afferents to a given brain nucleus using only immunohistochemistry. The existence of these pathways, however, must be verified by other neuroanatomical methods because of the problem of nerve fibers of passage.

Animals↗
PubMed1993

[Effectiveness and safety of 150 mg vs 300 mg ranitidine twice a day in duodenal ulcer].

394 patients with endoscopically diagnosed duodenal ulcer were randomly allocated to treatment with ranitidine 150 bid o ranitidine 300 mg bid in a prospective double-blind multicenter trial conducted in seven LatinoAmerican countries. Endoscopy at 4 weeks showed complete ulcer healing en 171 of 196 patients (87.2%) treated with ranitidine 150 mg bid and 178 of 198 (89.9%) treated with ranitidine 300 mg bid. Both treatment regimens were equally effective at rapidly reducing the incidence of ulcer-related symptoms. It is possible that higher dosage regimen of ranitidine would be useful in patients with more severe duodenal ulcer disease.

Adult↗
PubMed1992

[Hemodynamic differences do not exist in patients with adult respiratory syndrome with or without infection].

BACKGROUND: To verify whether patients with adult respiratory distress syndrome (ARDS), associated to sepsis or not, may be differentiated according to the values of the hemodynamic variables. METHODS: Thirty-two consecutive patients with ARDS admitted to an intensive care unit over a period of 32 months were prospectively studied. In 18 patients ARDS was associated to sepsis. The value of the hemodynamic variables were compared between both groups of patients (18 with sepsis and 14 without) within the first 24 hours of diagnosis of the syndrome. RESULTS: Mortality of patients with ARDS associated with sepsis was greater than in those without sepsis (78% vs 57%). In general both groups of patients with ARDS presented similar values of pulmonary hypertension (28 +/- 6 and 25 +/- 4 mmHg) with elevated pulmonary vascular resistance, and with an above normal cardiac index and ventricular function parameters. No significant differences were found in hemodynamic values, ventricular function and oxygen transport among patients with ARDS, with or without sepsis, or among survival or death in each group, or those considered in general. CONCLUSIONS: This study demonstrated that patients with the septic adult respiratory distress syndrome (ARDS) have the same hemodynamic changes as those observed in patients with ARDS without sepsis. This absence of differences may be explained by the presence of mechanisms common in sepsis and ARDS.

Adult↗
PubMed1992

Evaluation of two vaccines for the treatment of pythiosis insidiosi in horses.

Two vaccines to treat phythiosis insidiosi in horses were evaluated in 71 Costa Rican horses between 1982 to 1988. One vaccine used a cell-mass (CMV) as antigen and the other a soluble concentrated antigen (SCAV). Both vaccines cured horses infected with Pythium insidiosum (p value approximately 14%). The age of lesions prior to vaccination was important in the response of the horses to immunotherapy. All horses with lesions 0.5 months or less in duration were cured regardless of the vaccine used. Horses with lesions two or more months old did not respond to either vaccine. The age of the horses did not have any influence on their response to the vaccinations. The CMV produced a prominent inflammatory reaction at the side of injection, while the SCAV gave a low inflammatory reaction. In addition, the CMV lost its effectiveness two to three weeks after its preparation. By contrast, the SCAV maintained its ability to cure horses even after 18 months. Immunotherapy using SCAV can thus be used as the vaccine of choice in early cases of equine cutaneous pythiosis insidiosi.

Aging↗
PubMed1992

A novel mitogen-inducible gene product related to p50/p105-NF-kappa B participates in transactivation through a kappa B site.

A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.

Amino Acid Sequence↗
PubMed1992

Employment of antipeptide antisera to distinguish two closely related cytokines induced in human T cells.

AT464 and AT744 are two cytokines encoded by mitogen-induced genes from human T lymphocytes. These proteins belong to a family of structurally related chemotactic proteins associated with inflammation. By expression of their full length cDNAs in COS cells and in baculovirus-infected Sf9 cells, we found that pAT464 and pAT744 cDNAs represent secreted polypeptides of a molecular mass of about 8,000 and 11,000 Da, respectively. Biochemical characterization of these proteins has been persued through polyclonal antisera, which were derived to synthetic peptides. Using these sera for Western blotting analyses the recombinant AT464 and AT744 proteins could be detected as secreted products from transfected COS cells and from baculovirus-infected Sf9 cells. Similarly the native proteins could be detected in the supernatants of activated human peripheral blood T cells. The recombinant and the T cell-secreted AT464 and AT744 proteins appear to be identical as judged by their mobility by SDS-PAGE and by their reactivity with the rabbit polyclonal antisera.

Animals↗
PubMed1990

Cloning of a mitogen-inducible gene encoding a kappa B DNA-binding protein with homology to the rel oncogene and to cell-cycle motifs.

We have cloned and characterized a mitogen-inducible gene isolated from human T cells that predicts a protein of 968 amino acids. The amino-terminal domain has regions homologous to the oncogene rel and to the developmentally important gene dorsal of Drosophila. The carboxy-terminal domain contains repeat structures found in a variety of proteins that are involved in cell-cycle control of yeast and in tissue differentiation in Drosophila and Ceanorhabditis elegans, as well as in the putative human oncogene bcl-3 and in the ankyrin protein. A truncated form of the product of this gene translated in vitro is a DNA-binding protein which interacts specifically with the kappa B binding site found in many inducible genes, including the enhancer in human immunodeficiency virus. This gene is yet another in a growing list of important regulatory molecules whose expression is transcriptionally induced upon cellular activation.

Amino Acid Sequence↗
PubMed1990

Age-related changes in the subcortical afferents to the medial frontal cortex in mice: a WGA-HRP study.

The subcortical afferent projections to the mediodorsal part of the frontal cortex were studied both qualitatively and quantitatively in young (3 months), adult (12 months) and aged (22 months) Balb/c mice by means of the retrograde transport of wheat germ agglutinine-horseradish peroxidase (WGA-HRP). A progressive decrease in the number of afferents was observed during aging with a differential pattern of reduction as a function of the subcortical structures. In adult mice a large reduction of afferents occurs in the diagonal band of Broca, the posterior thalamic nucleus, the zona incerta, the lateral hypothalamic area, the nuclei of amygdaloid complex, the posterior hypothalamic nucleus, the reticular pontine nucleus, the dorsal and medial raphe nuclei and the dorsal tegmental nucleus. In aged animals, only the anteromedial and mediodorsal thalamic nuclei, as well as the locus coeruleus appear to be clearly affected.

Aging↗
PubMed1988

Kinetic lability of zinc bound to metallothionein in Ehrlich cells.

Ehrlich ascites-tumour cells normally contain a large concentration of Zn-metallothionein. When cells are placed in culture media, containing or pretreated with the metal-ion-chelating resin Chelex-100, they stop growing, remain viable and lose zinc specifically from the metallothionein (MT) pool. The kinetics of loss of zinc are first-order and are very rapid, having a rate constant of greater than or equal to 0.6 h-1. MT protein labelled with 35S is biodegraded with a rate constant of 0.07-0.014 h-1 in control cells, 0.08 h-1 in cells exposed to the zinc-deficient medium and 0.12-0.18 h-1 in cells treated directly with Chelex. Over the 6 h period in which zinc is totally lost from Zn-MT there is relatively little decrease in MT-like protein as measured by cadmium-binding to the 10,000-Mr protein fraction. Other pools of zinc and 35S-labelled protein turn over more slowly. There is no loss of zinc from rat liver Zn-MT that is dialysed against Chelex to model the possible reaction of the resin with Ehrlich-cell Zn-MT. However, Chelex does compete slowly for MT-bound zinc when resin and MT are directly mixed. Analysis of the known and possible pathways of zinc metabolism in cells in relationship to these rate constants shows that biodegradation of MT protein cannot account for the rate of loss of zinc from Zn-MT.

Animals↗
PubMed1988

Bone lesions caused by Pythium insidiosum in a horse.

A 5-year-old, female saddle horse developed a tumoral mass anterolaterally on the metacarpal region of its right front leg. Histopathological study showed hyaline, aseptate, broad hyphae in the sequestered coral-like necrotic masses. Radiographs revealed an extensive osteomyelitis with disorganized bone proliferation of the metacarpal bones, as well as exostosis of the distal radius and the proximal and distal row of carpal bones. The etiologic agent was detected histologically, isolated in culture and identified as Pythium insidiosum. Serological tests were positive. Immunotherapy was applied but no cure resulted. The horse was sacrificed and necropsy confirmed the X-ray findings.

Animals↗