Macrophage apoptosis in muscle tissue in experimental autoimmune myasthenia gravis

BACKGROUND: In adhesive small bowel obstruction, the early recognition of complications such as strangulation or volvulus is essential to choose between surgical or conservative initial treatment. The objective of this study was to determine prospectively the contribution of computed tomography (CT) to decision making in the management of these patients. METHODS: Patients with suspected adhesive small bowel obstruction had CT at admission. Patients with CT signs of volvulus or strangulation and/or clinical signs of peritoneal irritation underwent urgent surgery; other patients had conservative initial treatment. RESULTS: Fifty-four patients were evaluated. CT demonstrated signs of strangulation or volvulus in 19 patients, including three with signs of peritoneal irritation. Within this group, urgent laparotomy was performed in 17 patients and confirmed the CT diagnosis in 16. Thirty-seven patients without clinical or CT signs of complications had initial conservative treatment; among them, seven of 12 with a distal obstruction determined by CT required a delayed operation for persisting obstruction, compared with two of 25 patients with a proximal obstruction (P < 0.01). CONCLUSION: CT is useful for the evaluation of adhesive small bowel obstruction, to detect accurately patients with complications who require urgent operation and to determine the location of the adhesion, which represents a significant prognostic factor for success of conservative treatment.     

Effects of oral vanadyl treatment on diabetes-induced alterations in the heart GLUT-4 transporter

Vanadyl sulfate was administered orally during a 10-week trial period to streptozotocin-diabetic and control male rats to test the hypothesis that chronic vanadyl supplementation would prevent the decline in cardiac muscle cell glucose transporter protein (GLUT-4) that otherwise manifests in conjunction with insulin deficiency. Isolated cardiac myocytes and cardiac sarcolemmal vesicles were prepared from heart tissue of rats that had been maintained on the following regimens: untreated control, oral vanadyl-supplemented control (0.6 mg/ml), untreated diabetic (streptozotocin-induced; 60 mg/kg), and vanadyl-supplemented diabetic. Myocytes isolated from untreated diabetic rat hearts had decreased rates of glucose oxidation. Chronic, oral administration of vanadyl to diabetic rats maintained glucose oxidation rates of cardiac myocytes at control levels. Immunoblot analyses revealed that total cardiac myocyte and sarcolemmal GLUT-4 glucose transporter protein levels were significantly lower in the diabetic group relative to control. Vanadyl treatment of diabetic rats produced a normalization of both sarcolemmal GLUT-4 and total cardiac myocyte levels towards control levels. The reduction of GLUT-4 mRNA levels seen with untreated diabetes was also completely prevented with vanadyl treatment. These results demonstrate that chronic-oral vanadyl sulfate supplementation limits the decline in glucose oxidative capacity of cardiac myocytes that otherwise manifests in the untreated diabetic state. This action of vanadyl may occur via a mechanism that is linked to the preservation of sarcolemmal GLUT-4 protein levels.     

Staphylococcus aureus nasal colonization in HIV-seropositive and HIV-seronegative drug users

Five cases of adenoid basal carcinoma (ABC) of the uterine cervix were examined for the presence of p53 tumor suppressor gene, K-ras-2 oncogene, and human papillomavirus (HPV). A topographic genotyping approach was used to search for point mutations in K-ras-2 (exon 1 and 2) and p53 (exons 5 to 8) in archival formalin-fixed tissue blocks. Minute target sites were selected from polymerase chain reaction (PCR) amplified and directly sequenced tissue sections. Tissue sections were additionally subjected to immunohistochemical staining for p53 and WAF-1 protein. Because wild type p53 induces WAF-1 gene expression, immunohistochemical staining for WAF-1 protein using monoclonal antibodies may serve as an indirect means to test for p53 mutational damage. Mutational genotype was compared to histopathologic features and immunohistochemical staining. To study the role of HPV, L1 region consensus primers were used to amplify topographic samples, followed by HPV genotyping by direct sequencing and comparison to known viral strains. ABC was found to contain HPV in all cases, proven by genotyping to be HPV type 16 in each case. The virus showed no evidence of genomic variation from prototype HPV type 16 in the L1 segment examined. No K-ras-2 point mutations were identified. p53 immunopositivity was present in all tumors, being weak and focal in 4 and strong and diffuse in 1. WAF-1 immunostaining was positive in two tumors showing weak focal p53 immunopositivity. The single strong and diffuse p53 immunopositive tumor was negative for WAF-1 and was shown to contain a missense p53 point mutation (exon 7-codon 248 tryptophan). In conclusion, ABC is characterized by the presence of HPV type 16. K-ras-2 point mutation appears to play no role in the development of this tumor. p53 gene alterations are common including wild type hyperexpression (weak focal p53 immunopositivity, WAF-1 positivity, no mutational change) and p53 point mutational damage.     

p53 status does not determine outcome of E1B 55-kilodalton mutant adenovirus lytic infection

The ability of the adenovirus type 5 E1B 55-kDa mutants dl1520 and dl338 to replicate efficiently and independently of the cell cycle, to synthesis viral DNA, and to lyse infected cells did not correlate with the status of p53 in seven cell lines examined. Rather, cell cycle-independent replication and virus-induced cell killing correlated with permissivity to viral replication. This correlation extended to S-phase HeLa cells, which were more susceptible to virus-induced cell killing by the E1B 55-kDa mutant virus than HeLa cells infected during G1. Wild-type p53 had only a modest effect on E1B mutant virus yields in H1299 cells expressing a temperature-sensitive p53 allele. The defect in E1B 55-kDa mutant virus replication resulting from reduced temperature was as much as 10-fold greater than the defect due to p53 function. At 39 degreesC, the E1B 55-kDa mutant viruses produced wild-type yields of virus and replicated independently of the cell cycle. In addition, the E1B 55-kDa mutant viruses directed the synthesis of late viral proteins to levels equivalent to the wild-type virus level at 39 degreesC. We have previously shown that the defect in mutant virus replication can also be overcome by infecting HeLa cells during S phase. Taken together, these results indicate that the capacity of the E1B 55-kDa mutant virus to replicate independently of the cell cycle does not correlate with the status of p53 but is determined by yet unidentified mechanisms. The cold-sensitive nature of the defect of the E1B 55-kDa mutant virus in both late gene expression and cell cycle-independent replication leads us to speculate that these functions of the E1B 55-kDa protein may be linked.     

Amianthoid myofibroblastoma of the soft tissues

Myofibroblastoma (MF) is an uncommon, usually benign, mesenchymal tumor infrequently described in soft tissues. We report here on the clinicopathologic findings of a soft tissue MF (STMF) presenting in the neck of a 90-year-old man as a slowly growing and non-painful nodule, 4 cm in greatest diameter. Histology revealed a circumscribed lesion constituted of monomorphous bipolar spindle cells arranged in swirling fascicles with intervening broad bands of hyalinized collagen and well formed "amianthoid" fibers. Immunohistochemistry showed the spindle cells to be immunoreactive for vimentin, smooth muscle actin and muscle specific actin and, focally, for desmin; immunostaining for cytokeratin, epithelial membrane antigen, S-100 protein, factor VIII-related antigen, and CD34 was negative. Based on the present case and on those previously reported in the literature, STMF is characterized by: 1) exclusive incidence in the male sex; 2) variable immunoreactivity of the neoplastic cells for desmin, probably reflecting an origin from a peculiar subset of myofibroblasts, or, alternatively, a further myoid differentiation; 3) variable abundance of (hyalinized) collagen; 4) presence of amianthoid fibers. The combination of desmin immunoreactivity, frequently observed in MF of the breast, and amianthoid fibers, the main feature of MF of the lymph nodes, has never been observed in soft tissue MF. It is important to recognize STMF as a specific clinicopathologic entity to avoid confusion with other types of spindle cell proliferation and to differentiate it from other types of myofibromatosis.     

Bouyant density, conversion formulae, and the mole percent guanosine + cytosine content of Desulfovibrio sp

A reevaluation of the original buoyant density conversion formula used to calculate the molar percentage guanosine + cytosine (% G + C) contents of the accepted species of genus Desulfovibrio has been undertaken. It would appear that the formula used gives values 4-5% lower than those obtained using formulae more generally cited in modern literature. Recalculations of % G + C content values for Lesulfovibrio DNA are presented using the formulae of three different workers, and are compared with those values originally used in the classification of genus Desulfovibrio.