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A case of a 38-year-old male having an acinic cell adenocarcinoma of the parotid gland is reported. The tumor measured 22 cm and histologically it was of the papillary-cystic type. The following features were of interest: 1) the tumor size surpassed the size of previous reported acinic cell adenocarcinomas by 9 cm; and 2) the rarity of its histological variety (cystic papillary) demanded immunohistochemical and electron microscopic studies to confirm the diagnosis.

Assuntos

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We describe the clinicopathological characteristics and postmortem findings of three cases of intramucosal early gastric cancer (EGC) selected from nine cases of our series to characterize its unusual clinical behavior. All patients were treated at the Instituto Nacional de la Nutricion in Mexico City between January 1986 and December 1995. The following features were the most salient of the three cases: (1) The tumors were constituted by only few nests of intramucosal cells; two of them were signet-ring cell carcinomas and the other one was of the intestinal type. (2) Grossly, all tumors were inconspicuous. (3) All the patients had a short clinical course and in none of them the clinical diagnosis was suspected. (4) A wide dissemination was found at autopsy; additionally, in two of the cases, extensive lymphatic and venous thrombi and multiple secondary hemorrhages were found. (5) In all patients, the symptoms and deaths were caused by the metastases. No cases as early as those reported here were found either in the Japanese or in Western literature. Although larger series of EGC should be studied in our country, these findings suggest that at least in Mexico there is a group of EGC with unusual aggressive behavior.

Assuntos

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A possible sex difference in the mean sagittal area of the anterior commissure (AC) was investigated in normal, newborn-castrated, and perinatally-androgenized rats. A second experiment included castrated adult rats from each sex exposed to testosterone twelve days before sacrifice. In normal rats, as well as in those exposed to testosterone as adults, no quantitative difference was found in the AC. However, perinatal exposure to testosterone induced a 20-25% increase in the mean area of the AC of rats from each sex. It is proposed that gonadal sex steroids may have a reciprocal influence upon the structure of central olfactory pathways, due to the influences of the main olfactory system upon gonadotropin secretion.

Assuntos

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A mouse model of pulmonary tuberculosis induced by the intratracheal instillation of live and virulent mycobacteria strain H37-Rv was used to examine the relationship of the histopathological findings with the local kinetics production and cellular distribution of tumour necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha) and transforming growth factor-beta (TGF-beta). The histopathological and immunological studies showed two phases of the disease: acute or early and chronic or advanced. The acute phase was characterized by inflammatory infiltrate in the alveolar-capillary interstitium, blood vessels and bronchial wall with formation of granulomas. During this acute phase, which lasted from 1 to 28 days, high percentages of TNF-alpha and IL-1 alpha immunostained activated macrophages were observed principally in the interstium-intralveolar inflammatory infiltrate and in granulomas. Electron microscopy studies of these cells, showed extensive rough endoplasmic reticulum, numerous lysosomes and occasional mycobacteria. Double labelling with colloid gold showed that TNF-alpha and IL-1 alpha were present in the same cells, but were confined to separate vacuoles near the Golgi area, and mixed in larger vacuoles near to cell membrane. The concentration of TNF-alpha and IL-1 alpha as well as their respective mRNAs were elevated in the early phase, particularly at day 3 when the bacillary count decreased. A second peak was seen at days 14 and 21-28 when granulomas appeared and evolved to full maturation. In contrast, TGF-beta production and numbers of immunoreactive cells were low in comparison with the advanced phase of the disease. The chronic phase was characterized by histopathological changes indicative of more severity (i.e. pneumonia, focal necrosis and extensive interstitial fibrosis) with a decrease in the TNF-alpha and IL-1 alpha production that coincided with the highest level of TGF-beta. The bacillary counts were highest as the macrophages became large, vacuolated foamy cells, and containing numerous bacilli with immunoreactivity to mycobacterial lipids and lipoarabinomannan (LAM). These macrophages displayed poor and scarce TNF-alpha and IL-1 alpha immunostaining but still strong immunoreactivity to TGF-beta. These cytokine production kinetics and the spatial relationship between immunostained cells and lung lesions corroborate the important role of TNF-alpha and IL-1 alpha in the constitution of granulomas and immune protection during the early phase of the infection, and also suggest an important if not primary role for TGF-beta in the immunopathogenesis of the advanced forms of pulmonary tuberculosis.

Assuntos

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T-helper 1 (Th1) Th2 kinetics were studied by immunohistochemistry and molecular biology techniques (reverse transcriptase polymerase chain reaction. RT PCR, Southern-blot) during the course of pulmonary tuberculosis induced in BALB/c mice by the intratracheal instillation of the live and virulent strain H-37Rv. The histopathological study clearly showed two phases of the disease. The first one was an acute phase which was characterized by inflammatory infiltrate in the alveolar capillary interstitium, blood vessel and bronchial wall with formation of granulomas. In this acute phase which lasted from 1 to 28 days, a clear predominance of Th1 cells was observed, manifested by a high percentage of interleukin-2 (IL-2) positive cells in the inflammatory infiltrate and granulomas demonstrated by immunohistology, as well as a gradual increment of interferon-gamma (INF-gamma) m-RNA. This was followed by a chronic or advanced phase characterized by pneumonia, focal necrosis and fibrosis, with a Th0 balance due to an equivalent proportion of IL-2 and IL-4 positive cells in the lung lesions, that coincided with the highest level of INF-gamma and IL-4 mRNA. The cytofluorometric analysis of bronchial lavage cells, showed a predominance of CD4 T cells during the acute phase and CD8 T lymphocytes in the chronic phase, gamma-delta T lymphocytes showed two peaks, at the beginning (3 days) and at the end (4 months) of the infection. These results suggest that T-lymphocyte subset kinetics and the pattern of cytokines produced in the lung during tuberculosis infection changed over time and correlate with the type and magnitude of tissue injury.

Assuntos

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Primary endocrine neoplasms of intra- and extrahepatic biliary ducts are very rare. We describe the first case of a primary endocrine tumor of the common bile duct producing gastrin. A 53-year-old woman had a 3-year history of recurrent duodenal and gastric ulcers as well as obstructive jaundice. A small neoplasm was found in the lower third of the common bile duct, which showed diffuse gastrin production and focal synthesis of serotonin and pancreatic polypeptide by immunohistochemistry and electron microscopy. Although serum gastrin was within normal levels (90 ng/ml), symptoms of peptic acid disease could have been related to hypergastrinemia, since gastric and duodenal ulcers healed after surgical removal of the tumor. She has remained asymptomatic for 8 months.

Assuntos

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BACKGROUND AND METHODS: A possible association between hepatitis C virus infection (HCV) and membranoproliferative glomerulonephritis (MPGN) or membranous glomerulonephritis has recently been reported. The pathogenesis of this entity appears to be immunologically mediated. The purpose of this report is to describe the clinical, laboratory, and histopathological features of three patients with chronic HCV infection, without hepatitis B virus disease or autoimmune diseases, but with glomerular disease. RESULTS: All three patients had chronic hepatopathy stigmata, ascitis, peripheral edema, and normal blood pressure values. Laboratory results showed mild liver function abnormalities and normal levels of blood nitrogenous waste products. Microscopic hematuria, hypoalbuminemia, and variable proteinuria without hypercholesterolemia were found in all cases. All three had positive rheumatoid factor. Only one patient had positive antinuclear antibodies and antimitochondrial antibodies at low levels, and another displayed low C3 and C4 serum levels. Renal histology in the three cases showed type I membranoproliferative glomerulonephritis and hepatic cirrhosis in the liver biopsy. CONCLUSIONS: This report supports the association between chronic HCV infection and membranoproliferative glomerulonephritis. However, further studies are needed to establish more firmly the association as well as the mechanisms of pathogenesis and causality between them.

Assuntos

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Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.

Assuntos

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To evaluate the neuroprotective effect of transplants placed in the lesion zone after a complete spinal cord (SC) laceration, two independent series of experiments were carried out. In the first, allogeneic or xenogeneic fetal SC was transplanted into the gaps of the damaged lower thoracic SC of adult rats. In the transplanted rats the incidence of life-threatening complications was reduced, and the survival rate was increased compared with the control group (lesion, without implant). Histological examination showed less damage to the neighboring SC parenchyma in the transplanted rats. The measurement of this neuroprotective effect was made in a second series of experiments. Using the same model of SC injury, allogeneic fetal SC, autologous peripheral nerve and/or adipose tissue were implanted. Rats with implants of Gelfoam and damaged rats without implants were the controls. The implanted rats of all groups, including the Gelfoam group, showed a better survival rate than the nonimplanted rats. Significantly less damage to the neighboring SC parenchyma was measured in implanted rats with any of the live tissues tested compared with non-implanted rats, although no significant differences were observed between the Gelfoam group and the nonimplanted rats. Histological evidence of tissue implant survival was observed in all corresponding groups. It is concluded that the transplanted tissues tested here have a neuroprotective effect, possibly by acting as a buffer to neurotoxic substance(s) released by the stumps, and/or by exerting trophic effect(s) on the host.

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In rodents the vomeronasal system plays an important role in modulating the hypothalamic control of gonadotropin secretion. It is accepted that the anatomical pathways by which the vomeronasal organ influences the neuroendocrine aspects of the reproductive behavior involves a polysynaptic system, including the accessory olfactory bulb, the 'vomeronasal amygdala', the bed nucleus of the stria terminalis and medial preoptic and ventromedial hypothalamic nuclei. We found that 72 h after unilateral transection of the vomeronasal nerves of an ipsilateral orthograde degeneration is seen in the neuropil of the medial preoptic, ventromedial, and arcuate hypothalamic nuclei. This represents an anatomical evidence of a monosynaptic link between the vomeronasal neuroepithelium and the medial preoptic nucleus, and hypothalamus.

Assuntos