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Biomedical subjects

H Matta

Publications and source records attributed to H Matta.

At least 19 recordsLinked to original sources
PubMed2006

Induction of spindle cell morphology in human vascular endothelial cells by human herpesvirus 8-encoded viral FLICE inhibitory protein K13.

Human herpesvirus 8 (HHV8), also known as Kaposi's sarcoma-associated herpesvirus, is linked to the development of Kaposi's sarcoma, a disease characterized by the presence of distinctive proliferating spindle-like cells. Although HHV8 can induce spindle cell transformation of vascular endothelial cells in vitro, the viral gene(s) responsible for this phenotype remain to be identified. We demonstrate that expression of HHV8-encoded viral Fas-associated death domain protein-like IL-1beta-converting enzyme inhibitory protein K13 is sufficient to induce spindle cell phenotype in human umbilical vein endothelial cells (HUVEC), which is associated with the activation of the nuclear factor-kappaB (NF-kappaB) pathway and can be blocked by Bay-11-7082, a specific inhibitor of this pathway. K13 induces the expression of several genes known to be upregulated in HHV8-transformed vascular endothelial cells, such as interleukin (IL)-6, IL-8, CXC ligand 3 (CXCL3), orphan G protein coupled receptor (RDC1), cyclooxygenase-2 (COX-2) and dual-specificity phosphatase 5 (DUSP5). Furthermore, similar to K13, HHV8-induced spindle cell transformation of HUVEC is associated with NF-kappaB activation and can be blocked by Bay-11-7082. Thus, ectopic expression of a single latent gene of HHV8 is sufficient for the acquisition of spindle cell phenotype by vascular endothelial cells and NF-kappaB activation plays an essential role in this process.

Cells, Cultured↗
PubMed2006

Induction of IL-8 expression by human herpesvirus 8 encoded vFLIP K13 via NF-kappaB activation.

Human herpesvirus 8 (HHV-8) encodes a viral FLICE inhibitory protein (vFLIP), called K13, with homology to the prodomain of caspase 8. K13 has been postulated to protect virally infected cells against death receptor-induced apoptosis. We report that K13 leads to constitutive upregulation of IL-8 secretion by transcriptional upregulation of its promoter. K13-induced IL-8 promoter activation is dependent on an intact NF-kappaB-binding site and is associated with increased binding of classical NF-kappaB pathway subunits p65, c-Rel and p50, respectively. IL-8 production is defective in K13 mutants defective in classical NF-kappaB activation and is blocked by genetic and pharmacological inhibitors of this pathway. In contrast, K13 failed to activate the JNK/AP-1 pathway and deletion of AP-1-binding site in the IL-8 promoter or use of a specific JNK inhibitor had only a partial effect on K13-induced IL-8 promoter activation. Collectively, above results demonstrate that K13 is a major mediator of IL-8 production and therapeutic agents targeting K13-induced NF-kappaB pathway may have a role in the treatment of conditions in which HHV-8-induced IL-8 production plays a pathogenic role.

Binding Sites↗
PubMed2001

A case of Turcot's Syndrome in a child with malignant transformation.

Turcot's syndrome or the glioma polyposis syndrome is a rare variant of the polyposis syndrome and it is characterized by colonic polyposis and central nervous system neoplasm typically a glioblastoma or a medulloblastoma. We present a case of Turcot's syndrome in a child with malignant transformation.

Adenomatous Polyposis Coli↗
PubMed2000

Congenital pyloric atresia and junctional epidermolysis bullosa: a report of two cases.

The association between epidermolysis bullosa (EB) and congenital pyloric atresia (CPA) is rare, but is known distinct clinical entity with autosomal recessive inheritance. The outcome of such an association was universally fatal. This is a report of two newborns with EB and CPA, associated with additional aplasia cutis congenita in one case. One patient was treated postoperatively with phenytoin and survived. Aspects of the diagnosis, pathogenesis, and management are also discussed.

Ectodermal Dysplasia↗
PubMed2000

An immunoassay for detection of heat-stable proteases from thermoduric psychrotrophic Bacillus spp. of dairy origin.

A homogeneous preparation of a thermostable protease from Bacillus sp. B-17 was used to raise an antiserum in rabbits. IgG of this antiserum was used to study the antigenic relationship of proteases in cell-free extracts of 21 bacilli of milk origin. Based on immunological cross reactivity, the 21 bacilli were divided into 3 serological subgroups. To raise antibodies of broader specificity, protease from Bacillus sp. B-11 (group II) and B-3 (group III) were purified, mixed with purified B-17 protease, and an antiserum was raised against this mixture. IgG of this antiserum was purified (IgG anti-bacilli protease). A sandwich ELISA was standardized using IgG anti-bacilli protease as capture antibody. The assay could detect 1.2 ng ml(-1) of protease in milk or buffer, but the assay failed to detect 4 of 21 bacilli proteases. The results suggest that this assay is useful for the detection of proteases of Bacillus spp. in dairy industry.

Animals↗
PubMed1999

Synchronous bilateral Wilms' tumor.

Synchronous bilateral Wilms' tumor (WT) accounts for 5% of all WTs. Of 34 cases of WT we treated, 7 (20.6%) were bilateral, 5 of them males. This high frequency of bilaterality as well as the male preponderance in our series is different from that reported in other parts of the world; this may reflect regional variations of WT. The details of diagnosis, therapy, including the role of preoperative chemotherapy, and outcome are presented.

Antineoplastic Agents↗
PubMed1999

A method to overcome the inability to draw blood from central venous lines in children.

The insertion of central venous catheters has become an established practice in the management of children with different types of malignancies for the administration of chemotherapeutic agents, antibiotics, blood and blood products, as well as drawing blood for various investigations. A commonly encountered problem is that despite the catheter being patent it may be impossible to draw blood from it. We believe this is related to the cut of the catheter tip. To overcome this problem, a technique for cutting the tip of the catheter is described.

Blood Specimen Collection↗
PubMed1998

Isolation and partial characterization of a thermostable extracellular protease of Bacillus polymyxa B-17.

Bacillus polymyxa B-17, a sporeforming psychrotroph produced a thermostable protease. The protease was purified to homogeneity from cell free broth culture by precipitation with ammonium sulfate and gel filtration through Sephadex G-100. The enzyme had a temperature optimum at 50 degrees C and shared significant activity at 70 degrees C. The protease was also active over a wide range of pH, 5.5 to 10.0, and had optimum activity at pH 7.5. It was inhibited by metal chelating agents and has a molecular weight of 30 kDa.

Animals↗
PubMed1998

Esophageal atresia and tracheoesophageal fistula: success and failure rates in the United Arab Emirates.

The management of esophageal atresia (EA) and tracheoesophageal fistula (TEF) has improved markedly over the years, with a current overall survival of 80%-90%. This however, is not the case in developing countries, where mortality continues to be high. The results of treatment of 41 consecutive cases EA and/or TEF have been analyzed to determine factors pertinent to the outcome. The distribution of anomalies and a postoperative survival of 86.8% were comparable to those from developed countries. Aspiration pneumonia was unusually frequent in our patients (78%), but did not adversely influence outcome. Associated congenital anomalies as well as low birth weight continue to be important predictors of outcome in our setting. Our post-operative complications were similar to those from developed countries apart from a high incidence of stricture formation. This was attributed to gastroesophageal reflux, non-ventilation post-operatively, and the use of silk sutures to construct the anastomosis.

Esophageal Atresia↗
PubMed1997

An immuno-dot blot assay for detection of thermostable protease from Pseudomonas sp. AFT-36 of dairy origin.

A dot-ELISA technique for the detection of Pseudomonas protease was developed using IgG of anti-Pseudomonas AFT-36 protease as capture antibody. The detection limit of protease in buffer or milk was 1.01 ng ml-1. The procedure was performed at room temperature, took about 2.5 h and was economical. Protease AFT-36 is immunologically related to five out of seven Pseudomonas spp. The results suggest that the assay could be used to detect proteases in dairy products.

Animals↗
PubMed1996

Immune response to phospholipase-A fractions of Salmonella typhi on experimental typhoid infection in mice.

The intraperitoneal injection of Salmonella typhi into mice produced typhoid infection involving all the vital organs. Infection of liver was more persistent and progressive than in other organs. During the course of experimental infection, no humoral immune response was detected against phospholipase-A fractions upto 3 weeks after challenge, but significant cell mediated immunity (CMI) was found. Increased CMI response against protein antigens correlated well with the decreasing bacterial load, what suggested that CMI against proteins was important in pathogenesis of this disease.

Animals↗
PubMed1995

Inefficacy of intestinal secretory immune response to Cryptosporidium in acquired immunodeficiency syndrome.

BACKGROUND/AIMS: An alteration of the secretory immune response has been forwarded to explain frequent and chronic mucosal infections in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to explore the intestinal immunoglobulin (Ig) secretions in patients with AIDS and their relationships to cryptosporidiosis. METHODS: Patients with AIDS and enteric cryptosporidiosis (n = 12), other enteric infections (n = 10), and no identifiable enteric pathogen (n = 10) and human immunodeficiency virus-seronegative controls (n = 18) were studied. The number of intestinal IgA and IgM plasma cells of the duodenal lamina propria mucosa and total and anti-Cryptosporidium IgA, IgM, and IgG were measured in serum and feces. RESULTS: Although not significantly increased, the number of IgA and IgM plasma cells was greater in patients with AIDS (n = 20) than in controls (n = 5). In feces, total IgA outputs and specific anti-Cryptosporidium IgA levels were significantly higher in patients with AIDS and cryptosporidiosis than in the two other groups of patients with AIDS (P < 0.05 and P < 0.01, respectively) and controls (P < 0.001 and P < 0.01, respectively). Total fecal IgM output and specific anti-Cryptosporidium IgM coproantibodies were increased only in the Cryptosporidium-infected patients relative to the controls (P < 0.05). CONCLUSIONS: Despite the development of pathogen-specific mucosal antibody responses, patients with AIDS and cryptosporidiosis fail to clear the parasite.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Immunological responses to phospholipase-A of Salmonella typhi.

A 39 kD phospholipase-A was purified from Salmonella typhi. The enzyme was efficiently concentrated by precipitation with ammonium sulphate and purified by sequential use of column chromatography on DEAE-Sephacel and Sephadex G-100. Humoral and cellular immune responses were determined against both crude and purified phospholipase-A. Crude fraction was found to be more immunogenic than purified fraction.

Animals↗
PubMed1994

Factors affecting intra and extracellular phospholipase A production by Salmonella typhi.

The effect of various physico-chemical factors on the production of intra and extracellular phospholipase A by Salmonella typhi was investigated. Maximum intracellular enzyme levels were observed when cells were grown in brain heart infusion broth, after 16h of incubation at 37 degrees C. Highest level of extracellular phospholipase A was also seen in the same medium (pH 7.0), but after 24 h of incubation at 37 degrees C. Agitation during incubation enhanced the enzyme synthesis. Addition of surfactants to the growth media significantly decreased both intra and extracellular phospholipase A production.

Culture Media↗
PubMed1988

Risk to surgeons.

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Accidents, Occupational↗