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Biomedical subjects

M W Simon

Publications and source records attributed to M W Simon.

At least 37 records · Page 2Linked to original sources
PubMed1993

Apnea of infancy associated with Epstein-Barr virus infection.

The Epstein-Barr virus is one of the most common causes of communicable disease. The clinical manifestations of this virus may vary widely depending on a child's age when primary infection occurs. I describe in this report a child with apnea associated with Epstein-Barr infection.

Apnea↗
PubMed1993

Cutis marmorata telangiectatica congenita.

Cutis marmorata telangiectatica congenita (CMTC) is an uncommon benign condition presenting at birth with levido reticularis, telangiectasia, phlebectasia, and possible ulceration of the involved skin. Diagnosis is made through the clinical picture and supported by characteristic histopathologic changes when present. This condition should not be confused with manifestations of serious system disease and aggressive treatment is not indicated. We describe in this report a case of CMTC.

Child, Preschool↗
PubMed1992

Comparison of immunocytology to tissue culture for diagnosis of presumed herpesvirus dendritic epithelial keratitis.

OBJECTIVE: The objective of this study is to prospectively compare the sensitivity and specificity of immunodetection of herpes simplex virus (HSV) in impression cytology specimens obtained directly from presumed herpesvirus dendritic epithelial keratitis with virus isolation by tissue culture of cells scraped from the same lesion. METHODS: Corneal impression cytology and tissue culture were performed on 29 consecutive patients presenting with presumed herpesvirus dendritic epithelial keratitis during a 6-month period. Impression cytology of dendritic epithelial keratitis lesions with Millipore Biopore membranes were evaluated for the presence of antigens specific to HSV type I (HSV-1), HSV-2, and varicella-zoster virus (VZV) using monoclonal antibodies specific to these herpesviruses and immunofluorescent staining techniques. RESULTS: Tissue culture was positive for HSV-1 in 52% (13 of 25) of dendritic epithelial keratitis patients without skin lesions, and was negative for VZV in 4 patients with dendritic epithelial keratitis and skin lesions in the distribution of the first division of the trigeminal nerve. The remaining 12 tissue cultures showed no cytopathic effect. Compared with tissue culture, impression cytology was 100% sensitive (13 of 13) and 92% specific (11 of 12) for the diagnosis of HSV-1 dendritic epithelial keratitis (Kappa coefficient of agreement 0.92). Although our sample size for VZV dendritic epithelial keratitis was small, the impression cytology findings correlated with our clinical diagnosis more often than tissue culture (2 of 4 versus 0 of 4). CONCLUSION: Impression cytology allows simultaneous debridement of dendritic epithelial keratitis and, when combined with immunocytologic staining procedures, provides a simpler, more rapid, and less expensive alternative to tissue culture for the diagnosis of dendritic epithelial keratitis caused by HSV or VZV.

Antibodies, Viral↗
PubMed1983

The free amino acid pool in Leishmania tropica promastigotes.

The principal constituents of the free amino acid pool in Leishmania tropica promastigotes include alanine, glycine, serine, threonine, alpha-aminobutyric acid and ethanolamine. Changes in levels of the pool constituents during starvation, nutrient supplementation and treatment with a metabolic inhibitor (sodium fluoride) were followed. Several enzymes capable of converting amino acids to Krebs cycle intermediates were identified. It is suggested that during prolonged starvation which is accompanied by enhanced proteolysis, these enzymes enable the cells to utilize endogenous amino acids as carbon and energy sources. This is compatible with previous reports that Leishmania promastigotes in culture could grow on amino acids as growth substrates when carbohydrates are totally lacking.

Amino Acids↗
PubMed1978

Evidence for a functional glyoxylate cycle in the leishmaniae.

Isocitrate lyase (EC 4.1.3.1) and malate synthase (EC 4.1.3.2), the two enzymes characteristic of the glyoxylate cycle, were demonstrated in promastigotes of five species of Leishmania (L. brasiliensis, L. donovani, L. mexicana, L. tarentolae, and L. tropica). Both enzymes were present in cells grown in a medium containing 10 mM glucose. Substitution of glucose with 20 mM acetate did not enhance enzyme levels. Acetate was readily taken up and metabolized by the cells. The distribution of label from acetate into various intermediary metabolites indicates a functional glyoxylate cycle and its role in gluconeogenesis/glyconeogenesis. The glyoxylate cycle in conjunction with alanine-glyoxylate aminotransferase and glyoxylate-aspartate aminotransferase could also be important in providing glyoxylate, the precursor for glycine biosynthesis.

Acetates↗