Genetic structure and organization of the membrane attack complement components.
Explore the source record for details and available documents.
Complement Membrane Attack Complex↗
Biomedical subjects
S Gonzalez
Publications and source records attributed to S Gonzalez.
Chemical composition of the cell wall of lactic acid bacteria and related species.
In order to examine the relationship between biological activities and the cell wall content, the murein type and the teichoic acid of the cell wall from five strains of bacteria were studied. Two of these Lactobacillus casei CRL 431 and L. acidophilus CRL 730, are used in a commercial fermented milk (BIO MILK), which is believed to be beneficial for health. The other strains, Lactococcus lactis CRL 526, Pediococcus pentosaceus CRL 923 and Propionibacterium acidipropionici CRL 1198 were included in order to compare the cell wall structures of active and inactive strains. A method was designed to confirm the amino acids of the peptidoglycan in impure substrates. Four of the studied strains, L. casei, L. acidophilus, L. lactis and P. acidipropionici, contained glycerol teichoic acids. L. casei, L. acidophilus, P. pentosaceus and L. lactis contained A4 alpha type murein, while P. acidipropionici contained A3 gamma type. The capacity of orally administered peptidoglycans of the studied strains to stimulate phagocytosis by mouse peritoneal macrophages was analyzed. Only the PG of L. casei showed this activity. No differences were observed between active and inactive strains with respect to the chemical composition of the peptidoglycan. Therefore the biological activity is unlikely to be due to the peptidoglycan structure.
Animals↗
Differences between nuclear run-off and mRNA levels for multidrug resistance gene expression in the cephalocaudal axis of the mouse intestine.
P-glycoprotein is a multidrug transporter encoded by the mdr3 gene in the mouse intestinal epithelium. The aims of this study were to characterize the mdr3 gene expression in the cephalocaudal axis of the intestine in adult animals and during perinatal development, and to define the molecular mechanism responsible for the heterogeneous expression of the gene along the cephalocaudal axis. RNA extracted from stomach, duodenum, jejunum, ileum, cecum and colon was hybridized by slot blot and Northern blot using a mdr3 cDNA probe. The regulation of gene expression was investigated examining the rate of transcription by nuclear run-off analysis. Transport studies of rhodamine 123, a substrate of P-glycoprotein, were performed in everted jejunum and ileum. The level of mdr3 mRNA and P-glycoprotein found in ileum was 6-fold higher than the level found in duodenum. The regional pattern of mdr3 gene expression is established in the intestine of 10-day-old animals. Similar mdr3 hybridization signal in nuclear run-off assay was found in nuclei of enterocytes isolated from jejunum and ileum, suggesting that the heterogeneous expression of the mdr3 gene in the cephalocaudal axis of the small bowel may be predominantly regulated at the post-transcriptional level. Transport rate of rhodamine 123 from the serosal to mucosal side in everted ileum was higher than the rate of transport found in jejunum. These results indicate that enterocytes of the ileum may be more actively involved in the P-glycoprotein-mediated transport of xenobiotics into the intestinal lumen.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Time-dependent effects of dexamethasone on glutamate binding, ornithine decarboxylase activity and polyamine levels in the transected spinal cord.
Evidence exists that the spinal cord is a glucocorticoid-responsive tissue, and glucocorticoids have beneficial effects in cases of spinal cord injury. Using sham-operated rats, spinal cord transected (TRX) rats, and TRX animals receiving dexamethasone (DEX) 5 min or 24 h post-lesion, we have examined the following GC-sensitive parameters 6 h after DEX treatment: (1) binding of glutamate to NMDA-sensitive receptors; (2) the activity of ornithine decarboxylase (ODC); and (3) levels of polyamines. We found that glutamate binding in the dorsal horn (Laminae 1-2) and central canal were upregulated in TRX rats, whereas DEX had an additional stimulatory effect. 24 h post-lesion, glutamate binding was unmodified in TRX or TRX+DEX rats. ODC activity was increased 10-fold in rats killed on the day of transection but only 2-fold 24 h post-lesion. DEX reduced ODC activity on transection day but highly increased it when given 24 h after surgery. The content of the polyamines spermidine and spermine were unchanged after TRX or DEX treatment, in contrast to putrescine which increased in TRX rats and further increased in TRX+DEX rats when measured the day post-lesion. Thus, parallel increases in ODC and putrescine 1 day after the lesion, suggest that glucocorticoid effects on growth responses due to polyamines may develop at a late period. The changes of glutamate binding in the dorsal horn and central canal due to early glucocorticoid treatment, further suggest hormonal modulation of neurotransmission in sensitive areas of the deafferented spinal cord.
Animals↗
Rapid diagnosis of major variants of congenital epidermolysis bullosa using a monoclonal antibody against collagen type IV.
A simple and rapid procedure to diagnose major variants of congenital epidermolysis bullosa (EB) by means of immunohistochemical staining of collagen IV (CIV) in formalin-fixed and paraffin-embedded samples is described. Sixteen cases were stained with a monoclonal antibody (clone CIV 22) against collagen IV present in the lamina densa layer of the basement membrane. Electron microscopy was performed simultaneously. Twelve cases showed one of two staining patterns: an EB simplex pattern (seven cases) consisting of linear and continuous staining on the "floor" of the blister and an EB dystrophica pattern (five cases) showing a linear and discontinuous staining on the "roof" of the blister. In four cases, collagen IV staining was not reactive because of irreversible antigen loss due to inadequate fixation and/or embedding. In those cases with positive staining, an excellent correlation with electron microscopic diagnosis was achieved. This procedure allows a rapid diagnosis of major EB variants, especially where electron microscopy is not available, and also facilitates diagnosis by optimally orienting specimens for ultrastructural examination when available.
Adult↗
Further studies in deoxycorticosterone acetate treated rats: brain content of mineralocorticoid and glucocorticoid receptors and effect of steroid antagonists on salt intake.
We have studied the role of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) on salt appetite developed by deoxycorticosterone acetate (DOCA) treated rats. To this end, we measured the effects of DOCA given on alternate days on (1) salt intake; (2) MR and GR in hippocampus (HIPPO), amygdala (AMYG), and hypothalamus (HT); (3) the activity of ornithine decarboxylase (ODC), a GR-mediated response, and (4) the salt intake after treatment with the antiglucocorticoid RU 486 or the antimineralocorticoid ZK 91587. First, we demonstrated that 10 but not 1 mg DOCA induced natriogenesis. Forty-eight hours after adrenalectomy and 24 h after the last DOCA injection, 10 but not 1 mg hormone reduced binding to GR in HIPPO, AMYG, and HT. Both doses of DOCA also reduced the binding to MR in HIPPO, without changes in AMYG; in HT the 1-mg dose was without effect, but the natriogenic dose (10 mg) highly increased binding of [3H]-corticosterone to MR. Scatchard analysis demonstrated increased Bmax and Kd values in the HT of DOCA-treated rats. Occupation of GR by DOCA did not stimulate the ODC activity, in contrast to the four-fold increment effected by the glucocorticoid dexamethasone. Also, administration of RU 486 did not inhibit the sale intake promoted by DOCA, in contrast to ZK 91587 which partly delayed the natriogenic effect of DOCA. It is suggested that brain MR are involved in the natriogenic effect of DOCA, whereas the role of GR is inconclusive.(ABSTRACT TRUNCATED AT 400 WORDS)
Amygdala↗
Physiological mechanisms regulating the conversion of selenite to elemental selenium by Bacillus subtilis.
We have demonstrated that the common soil bacterium, Bacillus subtilis, reduces selenite to an insoluble and much less toxic product--the red form of elemental selenium. Reduction was effected by an inducible system that appears to deposit elemental selenium between the cell wall and the plasma membrane. Glucose and sucrose supported selenite reduction. Although malate and citrate supported growth, no significant reduction of selenite occurred, indicating the importance of the redox state of the culture substrate. Selenite reduction in the millimolar concentration range (i.e., cultures supplemented with 1 mM selenite) was not affected by a ten-fold excess of nitrate or sulfate--compounds that serve as alternate electron acceptors and antagonize selenite reduction by anaerobic bacteria. Similarly, nitrite and sulfite did not significantly affect the rate or extent of selenite reduction. B.subtilis was able to grow and produce selenium (Se degree) at selenite concentrations ranging from 0.6 microM to 5 mM (50 ppb to 395 ppm selenium). At the lowest selenite concentration tested, 50 ppb selenium, B.subtilis removed 95% of the selenite from the liquid phase. The results suggest that selenite is reduced via an inducible detoxification system rather than dissimilatory electron transport. The findings establish the potential utility of B.subtilis for the bioremediation of selenite-polluted sites.
Bacillus subtilis↗
Clinical experience with balanced reciprocal translocations.
Clinical experience with balanced reciprocal translocations: In order to evaluate past experience with respect to the occurrence of balanced reciprocal translocations (BRT) in patients with malformation syndromes and/or mental retardation (MS/MR) and in couples with reproductive failure, 4,335 karyotypes from the Genetics Unit of the Universidad del Zulia from January 1971 to December 1994 were reviewed, resulting in the identification of 15 cases of BRT (0.34%). All BRT were classic (CT) according to the number of breakpoints. In 66.6% of the cases, the indication for chromosome analysis was a MS/MR; 20% reproductive failure and, in 13.3% the BRT was a fortuitous finding. BRT were of familial origin in 6/15 (40%), 3/15 (20%) were de novo and the other 6/15 (40%) were of unknown origin. It was concluded that BRT can affect the phenotype, particularly when the request for the karyotype is motivated by MS/MR, and that genetic counseling in individuals at risk to be carrier is indicated.
Abnormalities, Multiple↗
Measurement of alpha s from energy-energy correlations at the Z0 resonance.
Explore the source record for details and available documents.
Journal Article↗
Comparison of interferon-gamma and interleukin-4 production by peripheral blood mononuclear cells and isolated T cells after activation with polyclonal T cell activators.
Controversial data have been reported regarding the ability of peripheral blood T cells to secrete interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) from atopic patients as compared to nonatopic healthy controls. In most of these studies, T cells in peripheral blood mononuclear cell preparations (PBMC) were stimulated with polyclonal T cell activators. Some of these activators are able to activate cells other than T cells in the PBMC preparations which may influence the lymphokine levels in supernatants of PBMC. To evaluate this, we compared the IFN-gamma and IL-4 levels in PBMC and isolated T cell preparations after activation with phytohemagglutinin (PHA), Concanavalin A (ConA), anti-CD3 plus phorbol myristate acetate (PMA), or ionomycin plus PMA. The IFN-gamma and IL-4 levels in the supernatants were calculated based on the percent T cells in the preparations. Whereas all activators induced significant IFN-gamma secretion, only ionomycin plus PMA stimulation induced large IL-4 secretion. In virtually all cases, the IFN-gamma levels calculated on a per T cell basis differed for PBMC versus isolated T cells. Whereas in some donors the IFN-gamma levels were higher in PBMC preparations than in T cells, in others it was the opposite. Similarly, in about one half of both normal and atopic donors tested, the IL-4 levels of activated PBMC were 2- to 7-fold lower than levels in isolated T cells. The data suggest that non-T cells have a significant effect on the IFN-gamma and IL-4 levels in supernatants of polyclonally activated PBMC.(ABSTRACT TRUNCATED AT 250 WORDS)
Humans↗
Acute abdominal pain after vesical catheterization in a kidney and pancreas graft recipient.
Explore the source record for details and available documents.
Abdominal Pain↗
Liver transplant program in Argentina: development and preliminary results.
Explore the source record for details and available documents.
Adolescent↗
Virological and biochemical long-term follow-up of patients with chronic hepatitis C treated with interferon.
We studied the long-term outcomes of 43 patients with chronic hepatitis C treated with one or two interferon cycles, in relation to hepatitis C virus RNA in serum and peripheral-blood mononuclear cells. After the first interferon cycle, 15 (35%) patients had normal transaminase levels, although only five of them had normal levels throughout follow-up (complete responders). After treatment, hepatitis C virus RNA was detected in serum and peripheral-blood mononuclear cells with a similar frequency among the five complete responders (60% and 40%, respectively) and the 10 responders with relapse (50% and 20%, respectively). During the follow-up of the complete responders (up to 27 mo), fluctuating viremia levels were found, as demonstrated by the intermittent serum hepatitis C virus RNA positivity. In responders with relapse serum hepatitis C virus RNA reappeared concurrent with the relapse, without changes in peripheral-blood mononuclear cells. A second interferon cycle was performed in 23 nonresponders. Six of them had normalized transaminase levels but four had relapses. After retreatment, hepatitis C virus RNA was detected in peripheral-blood mononuclear cells with the same frequency (50%) in complete responders and in responders with relapse. Loss of serum hepatitis C virus RNA was only achieved in responders with relapse. During the follow-up, half of the complete responders lost serum hepatitis C virus RNA. This marker reappeared in responders with relapse, and hepatitis C virus RNA was found de novo in PBMCs of one responder with relapse. None of the 17 nonresponders to retreatment lost hepatitis C virus RNA in serum or PBMCs during therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Collagenous spherulosis.
Explore the source record for details and available documents.
Adenoma, Pleomorphic↗
Production of acute bronchiolitis in guinea-pigs by human respiratory syncytial virus.
Respiratory syncytial virus (RSV) is the most important cause of acute bronchiolitis in young children, and is implicated in the pathogenesis of paediatric asthma. The present studies were designed to develop a model of acute RSV bronchiolitis in young guinea-pigs, that could be used to study the mechanisms of the acute bronchiolitis and its sequelae. Anaesthetized, one month old guinea-pigs received either 4 x 10(3) plaque forming units of Long strain human RSV or uninfected cell culture medium intranasally. Bronchiolar inflammation was assessed 6 days (n = 10 RSV-inoculated; n = 10 controls) and 14 days (n = 10 RSV-inoculated; n = 9 controls) postinoculation using a semiquantitative histological scoring system. Viral replication within the lung was evaluated by culture, and the intrapulmonary distribution of viral antigens was evaluated by immunohistochemistry. The RSV-inoculated group showed histological evidence of acute bronchiolitis 6 days after inoculation, which subsided by Day 14. Replicating virus was cultured from the lungs of 9 out of 10 RSV-inoculated animals on Day 6, and 2 out of 10 animals on Day 14, with no growth from control animals. Viral antigens were identified primarily within airway epithelial cells on Day 6, and within alveolar macrophages on Day 14. Intranasal inoculation of human RSV into guinea-pigs provides a model of acute RSV bronchiolitis that may facilitate the study of both the pathogenesis of acute infection and the possible role of RSV in the subsequent development of nonspecific bronchial hyperresponsiveness in children.
Acute Disease↗
Meningothelial meningioma with "amianthoid" fibers. Case report with ultrastructural study.
The case of a meningothelial meningioma with 'amianthoid' fibers in a 48-year-old woman is presented. By light microscopy the tumor showed the typical features of meningothelial meningioma and rounded, deeply eosinophilic, and fibrillary areas, especially around and/or in the vicinity of blood vessels. These fibers are also called 'amianthoid' fibers. Ultrastructurally, these foci were made up of disorderly arranged and interwaving mature collagen fibrils with a variable width between 40 and 190 nm. No evidence of intracellular collagen synthesis by the tumor cells was found. The presence of 'amianthoid' fibers does not seem to carry any prognostic significance.
Collagen↗
Multidrug resistance gene and P-glycoprotein expression in gastric adenocarcinoma and precursor lesions.
Overexpression of the Multiple Drug Resistance gene (MDR1) has been proposed as a major mechanism related to both intrinsic and acquired resistance to chemotherapeutic agents. The gene product is a membrane protein (P-glycoprotein), that acts as an energy-dependent drug efflux pump decreasing drug accumulation in resistant tumor cells. We have characterized MDR1 and P-Glycoprotein expression in human gastric adenocarcinoma and in precursor lesions. MDR1 mRNAs, analyzed by dot-blot technique, were detected in 9 of 10 non-tumoral gastric mucosae and in 8 of 10 gastric adenocarcinomas. Immunohistochemical analysis, using the MRK16 monoclonal antibody, revealed heterogeneous expression of P-Glycoprotein in individual cells. The P-Glycoprotein was found on the surface of cells of gastric areas with intestinal metaplasia subtype III. This type of intestinal metaplasia, also called "colonic metaplasia", has been strongly associated with a high risk for the development of gastric cancer. The fact that the P-Glycoprotein was detected in this precursor lesion is consistent with the intestinal metaplasia-dysplasia and carcinoma sequence proposed in the histogenesis of this tumour. The finding that P-Glycoprotein was heterogeneously expressed in malignant cells of some gastric adenocarcinomas also suggests that this transporter system probably contributes to primary and secondary multidrug resistance in this neoplasm.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Ultrastructure of mesothelial regeneration after intraperitoneal injection of asbestos fibres on rat omentum.
In order to describe the ultrastructural features of the early phases of regenerating mesothelium in rat peritoneum, 69 cases were examined after intraperitoneal injection of 0.05-15 mg crocidolite, chrysotile B and other mineral and synthetic fibers. The findings show the presence of intermediate or transition cells between proliferating submesothelial connective tissue cells bearing the ultrastructural phenotype of myofibroblasts and mature fully regenerated mesothelium. Our results and data accumulated in the literature provide strong support for the hypothesis of submesothelial cells origin for regenerating mesothelium.
Animals↗