Role of Gq alpha in insulin-stimulated glucose uptake by C6 glioma cells

To investigate the possibility that insulin-stimulated glucose uptake in C6 cells is due to transactivation of a G protein-mediated pathway, the role of Gq alpha in insulin signaling was studied. Insulin stimulation of [3H]2-deoxy-D-glucose (2DG) uptake by C6 cells was time- and concentration-dependent: at a concentration of 1 microM, insulin stimulated 2DG uptake by C6 cells by about 30% (p < 0.05). Pertussis toxin treatment of C6 cells did not alter the ability of insulin (1 microM) to promote 2DG uptake, ruling out the involvement of Gion in insulin-stimulated hexose uptake. Next, C6 cells were transfected with Gq alpha cDNA for 48 h, challenged with 1 microM insulin, and 2DG uptake by the cells was determined. Insulin-stimulated 2DG uptake was 1.14 +/- 0.03 and 1.75 +/- 0.19 nmol/min/mg protein in mock- and Gq alpha-transfected cells, respectively (p < 0.05); insulin stimulated 2DG uptake in Gq alpha-transfected cells by 54%. These results suggest an involvement of Gq alpha in the transactivation of the G protein signal transduction pathway by insulin.

Comparative histopathology of scabies versus nodular scabies

Comparative histopathology was studied in 25 cases of scabies versus 25 cases of nodular scabies which were selected from Dermato-Venereology out patients. Salient differences observed were that in scabies lifting of stratum corneum at places was seen in all 100% cases, spongiosis in 100%, spongiotic vesicles in 28%, burrows in 56%, mite in 40% and vasculitis in 28% whereas in nodular scabies acanthosis was seen in 100%, pseudo epitheliomatous hyperplasia in 8%, burrows in 48%, mite in 24% and vasculitis in 84%. In nodular scabies, dermal infiltrate in 32% cases was arranged as lymphoid follicles with admixture of plasma cells and eosinophils.

Comparison between two techniques for modeling interface conditions in a porous coated hip endoprosthesis

The geometric and material non-linearities occurring at implant interfaces require a non-linear foate element analysis to simulate accurately the interface conditions. Reviewing the literature, it was found that mainly three different non-linear interface elements have been developed to simulate the interface bounding conditions. While these different types of interface elements have been used to predict micromotions and interface stresses for different geometrical configurations and under different loading conditions, no study has attempted to compare the performance of these elements under similar conditions. The objective of this study is to compare two non-linear interface modeling techniques using gap elements and joint/interface elements. A simplified three-dimensional geometrical model was developed to compare interface stresses and micromotions for both fully and partially coated models. The results show that both non-linear modeling techniques predict dissimilar results for the interface stresses in bone and prosthesis sides. For the fully coated model, and on the bone side, joint/interface elements predict a gradual decrease in stresses from distal end to proximal end. However, 'gap' elements predict almost constant stresses in the mid-stem region and higher stresses at the distal end. On the prosthesis side, small stress differences occur only at the distal and proximal ends. For the partially coated model, most significant stress dissimilarities occur in the uncoated section. The relative micromotions at the interface were also determined. It was found that micromotion patterns obtained using both techniques were similar with higher magnitudes in the case of the 'gap' elements.

The chemistry of the S-nitrosoglutathione/glutathione system

S-Nitrosothiols have generated considerable interest due to their ability to act as nitric oxide (NO) donors and due to their possible involvement in bioregulatory systems-e.g., NO transfer reactions. Elucidation of the reaction pathways involved in the modification of the thiol group by S-nitrosothiols is important for understanding the role of S-nitroso compounds in vivo. The modification of glutathione (GSH) in the presence of S-nitrosoglutathione (GSNO) was examined as a model reaction. Incubation of GSNO (1 mM) with GSH at various concentrations (1-10 mM) in phosphate buffer (pH 7.4) yielded oxidized glutathione, nitrite, nitrous oxide, and ammonia as end products. The product yields were dependent on the concentrations of GSH and oxygen. Transient signals corresponding to GSH conjugates, which increased by one mass unit when the reaction was carried out with 15N-labeled GSNO, were identified by electrospray ionization mass spectrometry. When morpholine was present in the reaction system, N-nitrosomorpholine was formed. Increasing concentrations of either phosphate or GSH led to lower yields of N-nitrosomorpholine. The inhibitory effect of phosphate may be due to reaction with the nitrosating agent, nitrous anhydride (N2O3), formed by oxidation of NO. This supports the release of NO during the reaction of GSNO with GSH. The products noted above account quantitatively for virtually all of the GSNO nitrogen consumed during the reaction, and it is now possible to construct a complete set of pathways for the complex transformations arising from GSNO + GSH.

Effects of ethanol on GLUT1 protein and gene expression in rat astrocytes

Effects of ethanol on glucose transporter gene expression were examined in cultured rat astrocytes. Exposure to 50 or 100 mM ethanol for 18 hours significantly inhibited hexose uptake and reduced the number of glucose transporters, as indicated by binding studies with cytochalasin B. Indirect immunofluorescence and immunoperoxidase staining showed marked reduction of the GLUT1 glucose transporter by exposure to 100 mM ethanol for 5 or 18 hours, but no obvious change in response to 50 mM ethanol. Western blot analysis showed GLUT1 protein levels to be decreased by 52 +/- 12% (p < 0.05) after exposure to 100 mM ethanol for 18 hours. In situ hybridization histochemistry indicated an increase in steady-state GLUT1 mRNA in astrocytes exposed to 50 or 100 mM ethanol for 5 or 18 hours. Quantitation of GLUT1 mRNA levels by northern blot analysis showed that GLUT1 mRNA levels were increased by 59 and 112% in cells treated for 5 h with 50 and 100 mM ethanol, respectively. A similar effect was observed after treatment for 18 hours, but ethanol did not alter actin gene expression. Experiments using actinomycin D to block RNA synthesis suggest that this increase in steady-state mRNA level results from increased message stability. These results suggest that ethanol acts on GLUT1 gene expression at the post-transcriptional level.

Immunochemical structure of the OmpD porin from Salmonella typhimurium

The OmpD porin was isolated and purified from Salmonella typhimurium strain SH 7454 (ompC::Tn10), digested with cyanogen bromide (CNBr) and the peptide fragments were separated by SDS-PAGE. N-terminal sequencing identified a total of 96 residues from four distinct peptides. The sequence showed that OmpD is homologous to NmpC (75% identity), Lc(75%) and OmpC (70%) from Escherichia coli, and OmpC (68%) from S. typhimurium. The sequence was essentially identical to the translated sequence of an nmpC-like gene of S. typhimurium, currently placed at 38.6 centisomes of the chromosome. Our results and other data suggest, however, that this gene is actually the ompD gene, which is more correctly placed in the 34 centisome region of the chromosome. The CNBr-generated peptides were also screened with 16 anti-S. typhimurium OmpD monoclonal antibodies by Western blotting. These results, in conjunction with the prediction of the OmpD folding pattern based on the known three-dimensional structure of E. coli OmpF, showed a close immunological relationship among S. typhimurium OmpD and E. coli NmpC and Lc, and a strong conservation of sequences within the transmembrane beta strands of these porins and E. coli OmpC, PhoE and OmpF, and Salmonella typhic OmpC.

Bicarbonate inhibits N-nitrosation in oxygenated nitric oxide solutions

N-Nitrosation in oxygenated nitric oxide (NO middle dot) solutions was previously shown to be significantly inhibited by phosphate and chloride presumably by anion scavenging of the nitrosating agent nitrous anhydride, N2O3 (Lewis, R. S., Tannenbaum, S. R., and Deen, W. M. (1995) J. Am. Chem. Soc. 117, 3933-3939). Here, bicarbonate is shown to exhibit this same inhibitory effect. Rate constants for reaction of morpholine, phosphate, and bicarbonate with N2O3 relative to N2O3 hydrolysis at pH 8.9 were determined to be (3.7 +/- 0.2) x 10(4) M-1, (4.0 +/- 0.9) x 10(2) M-1, and (9.3 +/- 1.5) x 10(2) M-1, respectively. The morpholine and phosphate rate constants at pH 8.9 are similar to those reported at pH 7.4 assuring that these results are relevant to physiological conditions. The rate constant for this previously unrecognized reaction of bicarbonate with N2O3 suggests the strong scavenging ability of bicarbonate; accordingly, bicarbonate may contribute to reducing deleterious effects of N2O3. This is biologically important due to substantial bicarbonate concentrations in vivo, approximately 30 mM. Bicarbonate was previously shown to alter peroxynitrite reactivity; however, carbon dioxide is the probable reactive species. Bicarbonate is therefore potentially important in determining the fate of two reactive species generated from nitric oxide, N2O3 and ONOO-, and may thus act as a regulator of NO middle dot-induced toxicity.

Immunoprotection by monoclonal antibodies to the porins and lipopolysaccharide of Salmonella typhimurium

Monoclonal antibodies (MAbs) were raised against the outer membrane (OM) antigens of Salmonella typhimurium. Enzyme-linked immunosorbent assays and Western immunoblots indicated that 10 MAbs in the panel were specific for surface epitopes, and 10 recognized buried epitopes of OmpC or OmpD porins; three MAbs reacted with smooth lipo-polysaccharide (LPS), two bound rough LPS, and the remaining three MAbs apparently reacted with a porin-LPS complex. We screened these MAbs and immune polyclonal sera in CAF1 (Ity) mice for their relative immunoprotective potential against a challenge with 10 to 500 LD50 of the virulent S. typhimurium LT-2 strain WB600, or against two LD50 of purified OM from this organism. Polyclonal sera that contained high titers of antibodies to porin monomers and trimers, and LPS, provided significant protection (33 to 100% survivors). Antiporin MAbs, when administered individually, did not protect or prolong the survival of mice. A mixture of MAbs with specificity for the surface, but not buried epitopes of porins, prolonged the survival of mice against endotoxemia, but none provided significant protection against mouse typhoid. MAbs specific for smooth (but not rough) LPS on the other hand, conferred significant protection against endotoxemia and mouse typhoid. Finally, MAbs that presumably recognized epitopes present in porin-LPS complexes, were also protective against endotoxemia and mouse typhoid. These results support the role of antibodies to LPS O-chains, porin-LPS complexes, and to a lesser degree, native porins in acquired resistance to infection by S. typhimurium.

Sarcoid heart disease: a rare cause of chest pain and malignant cardiac arrhythmia in a young Asian man. A case report

Cardiac sarcoidosis is a disease of young adults. In most cases, it presents with sudden death, arrhythmia, conduction disorders, heart failure, or cardiomyopathy. The authors describe a young Indo-Asian man with cardiac sarcoidosis who presented acutely with chest pain and malignant cardiac arrhythmias. The diagnosis of cardiac sarcoidosis should be considered in all young patients with unexplained arrhythmias or heart failure or in cases of sudden death.

Ethanol-induced changes in insulin-like growth factors and IGF gene expression in the fetal brain

Brain growth retardation is a major feature of the fetal alcohol syndrome (FAS). Insulin-like growth factors (IGF-I and IGF-II) have been shown to exert significant metabolic and growth-promoting effects. Previously, we showed that circulating levels of IGF-I as well as hepatic gene expression of both IGFs were decreased in newborn offspring of rats fed ethanol during pregnancy. This study investigated the effects of maternal ethanol ingestion on fetal rat brain growth and on levels of IGF-I and IGF-II, as well as their mRNAs, in fetal brain. IGF-binding protein (IGFBP) levels also were determined. Rats were fed 5% w/v ethanol in a liquid diet during gestation (EF group). Weight-matched animals were pair-fed equicaloric control diet (PF group) or were fed ad libitum (AF group). The mean fetal brain weight of EF offspring was 13% and 16% lower (P < 0.01) than that of PF and AF offspring, respectively. Body weight of EF pups was decreased to a greater extent, resulting in higher brain to body weight ratios in EF pups than in either control group (P < 0.05). IGF-I levels in EF pups decreased by 33% and 41% compared with the corresponding PF and AF values (P < 0.01). IGF-I mRNA levels decreased by 27% and 40% compared with PF and AF values, respectively. A positive correlation was observed between brain IGF-I level and brain weight (r = 0.561, P < 0.01). IGF-II levels were not affected despite a 50% decrease in IGF-II expression. In PF animals, the fetal brain IGF-I and IGF-II mRNA levels were reduced by 28% and 21%, apparently in response to undernutrition. IGF-binding proteins levels were low in the EF group but not statistically significant compared with control values. The diminished fetal brain concentration of IGF-I and decreased gene expression of IGFs may play a role in brain growth retardation associated with FAS.

Syngeneic bone marrow transplantation without conditioning in a patient with paroxysmal nocturnal hemoglobinuria: in vivo evidence that the mutant stem cells have a survival advantage

A 10-year-old girl with paroxysmal nocturnal hemoglobinuria (PNH) received an infusion of syngeneic bone marrow without preparative marrow ablation or immunosuppression. Following transplant, the patient became asymptomatic in concordance with an increase in the percentage of peripheral blood cells with normal expression of glycosyl phosphatidylinositol-anchored proteins (GPI-AP). However, molecular analysis suggested engraftment of a relatively small number of donor stem cells and persistence of an abnormal stem cell with mutant PIG-A. During 17 months of observation, the percentage of cells with normal GPI-AP expression gradually decreased, while intravascular hemolysis progressively increased. Approximately 16.5 months post-transplant, the patient once again became symptomatic. Together, these results indicate that syngeneic marrow infusion provided a clinical benefit by increasing the proportion of erythrocytes with normal expression of GPI-anchored complement regulatory proteins without supplanting the abnormal stem cells. However, evidence of insidious disease progression following the marrow infusion implies that the abnormal stem cells have a survival advantage relative to the transplanted stem cells. Thus, these studies contribute in vivo data in support of the hypothesis that PNH arises as a consequence of a pathological process that selects for hematopoietic stem cells that are GPI-AP-deficient.

Modulatory influence of chlorophyllin on the mouse skin papillomagenesis and xenobiotic detoxication system

The present study evaluates the modulatory potential of chlorophyllin (CHL) on the murine skin papillomagenesis pattern and its influence on the levels of biotransformation system enzymes. Topical application of CHL (100 mg/kg body weight/day) during peri-, post- or peri- and post-initiational stages of 7,12-dimethylbenz[a]anthracene (DMBA)-induced papillomagenesis, significantly (P < 0.01) reduced the (i) tumor burden to 3.68, 3.56 and 3.33 (positive control value: 5.89); (ii) cumulative number of papillomas to 59, 57 and 60 (positive control value: 112); and (iii) incidence of mice bearing papillomas to 88%, 88% and 90%, respectively (positive control value 100%). CHL treatment alone or during peri-, post-, or peri- and post-initiational stages significantly elevated the glutathione S-transferase (GST) and -SH levels in the liver and skin tissue of the murine system. The potential of CHL in modulating the process of carcinogenesis is suggested by the altered levels of biotransformation system enzymes. The implications of the biochemical changes and inhibition of tumor incidence by CHL are discussed.

Radioprotection of mice following garlic pretreatment

Freshly prepared aqueous extract of garlic was tested in mice for its possible in vivo protective effect against gamma-radiation-induced chromosomal damage. In the same animals, the changes in the sulphydryl content and glutathione S-transferase activity were evaluated. Three doses of garlic extract [125, 250 and 500 mg kg-1 body weight (bw)] were administered orally for five consecutive days and the animals were exposed to 0.25, 0.5, 1.0 and 2.0 Gy gamma-radiation 2 h after the final feeding. The results of the bone marrow micronucleus test revealed that pretreatment with garlic extract was effective in reducing gamma-radiation-induced chromosomal damage. Against 0.25 Gy gamma-radiation, a high dose of 500 mg kg-1 bw garlic extract was required to significantly reduce the chromosomal damage. All the three doses of garlic extract were effective in exerting a protective effect against 0.5, 1.0 and 2.0 Gy gamma-radiation. However a dose-related effect was observed only against 2.0 Gy. The sulphydryl content and glutathione S-transferase activity registered a significant increase after either pretreatment with garlic with extract or irradiation. In the garlic extract pretreated irradiated animals, a significant reduction was observed in the sulphydryl content and glutathione S-transferase activity.

Lipomas of the internal auditory canal

Lipoma of the internal auditory canal is a rare tumor that may be confused clinically with the much more common vestibular schwannoma. We present two cases of lipoma of the internal auditory canal. The clinical presentation is indistinguishable from that of vestibular schwannomas. The high signal intensity on T1-weighted magnetic resonance imaging, both with and without contrast, is consistent with other reports of lipoma. Review of the literature shows that lipomas of the internal auditory canal are histopathologically similar to lipomas of the cerebellopontine angle. The symptoms, erosive effect on the auditory canal, and gross appearance of this uncommon tumor are sometimes difficult to differentiate from those of a vestibular schwannoma. The diagnosis can be established by intraoperative examination of frozen sections.

AUUUA-specific mRNA binding proteins in astrocytes

Binding of ribonucleoproteins to specific regions of mRNA can alter mRNA stability. This level of posttranscriptional regulation has been shown to play a major role in gene expression of eukaryotic cells. This process involves the binding of ribonucleoproteins to specific region(s) of unstable, rapidly degrading mRNAs such as those found in various cytokines, lymphokines, and oncogenes, thereby increasing the mRNA's stability. In many instances the instability of the mRNA has been mapped to an AU-rich motif in the 3' untranslated region. We transcribed RNA molecules containing four reiterations of an AUUUA motif, and demonstrated with RNA- band shift experiments that the AUUUA motif complexes with phosphorylated AUUUA-specific 43-47 kDa mRNA binding protein(s) found in the cytosol of both rat brain and cultured rat astrocytes.

Nodular colloid degeneration over herpes zoster scars

A rare case of nodular colloid degeneration is reported which presented clinically as plaques studded with soft yellow papules simulating adult colloid milia superimposed only on herpes zoster scars of right side of the face.

Diabetic patients' alcohol use and quality of life: relationships with prescribed treatment compliance among older males

One hundred fifty-four males attending an outpatient diabetes clinic were interviewed to determine the incidence of alcohol use among them and to identify mechanisms by which alcohol use adversely affects the control of diabetes. Specifically, we determined how diabetic patients' use of alcohol is related to compliance with their diabetes treatment regimen, and diabetic patients' expectations of benefits from drinking alcohol and actual alcohol use is related to their quality of life. Greater alcohol use was related to poorer prescribed insulin injection compliance (p < 0.01), and stronger expectations of immediate, positive consequences of drinking alcohol were related to several indices of lower quality of life (p < 0.005). These results imply interactive relationships among diabetics' alcohol use and expectancies, treatment compliance, and quality of life.

The transcontinental transmission of tuberculosis: A molecular epidemiological assessment

Many tuberculosis control activities are based on principles learned from studies of tuberculosis transmission. To date, these have largely been limited to outbreak investigations in confined geographical regions. In this report conventional and computerized DNA fingerprint- based approaches were integrated to demonstrate that the most widely prevalent strain of Mycobacterium tuberculosis from New York City was cultured from only 1 of 755 patients in San Francisco, Calif, who was a traveling salesman. Large-scale molecular epidemiologic studies may provide a better understanding of the dynamics of tuberculosis transmission between geographic regions and suggest rational measures to interrupt such transmission.

Molecular basis of the heterogeneity of expression of glycosyl phosphatidylinositol anchored proteins in paroxysmal nocturnal hemoglobinuria

The purpose of these studies was to determine the molecular basis of the phenotypic mosaicism that is a defining feature of paroxysmal nocturnal hemoglobinuria (PNH). Analysis of T cell clones from a female patient revealed four distinct phenotypes based on surface expression of glycosyl phosphatidylinositol-anchored proteins (GPI-AP). When PIG-A (the gene that is mutant in PNH) from these clones was analyzed, four discrete somatic mutations were identified. Analysis of X chromosomal inactivation among the abnormal T cell clones was consistent with polyclonality. Together, these studies demonstrate that the phenotypic mosaicism that is characteristic of PNH is a consequence of genotypic mosaicism and that, at least in this case, PNH is a polyclonal rather than a monoclonal disease. That four distinct somatic mutations were present in a single patient suggests that in conditions that predispose to PNH PIG-A may be hypermutable.

Psoriasiform sarcoidosis associated with depigmentation

A 65-year-old female had psoriasiform, depigmented, angiolupoid, lupus pernio, papular and verrucous plague type of cutaneous sarcoidosis. Systemic involvement (hepatomegaly, bilateral persistent swelling of the parotid glands, pain in the hands, weakness and atrophic rhinitis of the left nasal cavity) was also present. The histopathological features of a non-caseating epithelioid cell granuloma with giant cells confirmed the diagnosis. The patient is responding favourably to prednisolone 10 mg daily.