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Biomedical subjects

R Munn

Publications and source records attributed to R Munn.

26 records · Page 2Linked to original sources

Carcinosarcoma (malignant mixed tumor) of the parotid: report of a case with a pure rhabdomyosarcoma component.

BACKGROUND: Carcinosarcoma or true malignant mixed tumor of the parotid gland is extremely rare, accounting for < 1% of all salivary gland malignancies. METHODS: A 63-year-old woman presented with a 5-cm right parotid mass which was resected with a radical parotidectomy and infratemporal fossa dissection. RESULTS: The tumor contained two distinctive histologic patterns, that of a poorly differentiated ductal carcinoma and a pleomorphic rhabdomyosarcoma. Additionally, a residual focus of pleomorphic adenoma was present peripherally. Immunohistochemical and electron microscopic studies confirmed the skeletal muscle differentiation. CONCLUSIONS: The pattern of combined rhabdomyosarcoma and ductal carcinoma has not been previously reported and adds further evidence to the myoepithelial derivation of these tumors.

Carcinosarcoma↗

Morphologic study of intermediate filaments in rat hepatocytes.

Rat liver perfused with 0.5% Triton X-100 for 15 to 90 min followed by 1% sodium dodecyl sulfate for 30 min were studied by electron microscopy and polyacrylamide gel electrophoresis. After 15 min of perfusion, a rich network of intermediate filaments and microtubules was visualized in the cytoplasm of hepatocytes. Using stereopairs, branching was visualized. Connections of filaments were noted with nuclei, centrioles, microtubules, vesicles, and rough endoplasmic reticulum. The existence of connections supported the concept that intermediate filaments may function to integrate mechanically the cytoplasmic space as postulated by Lazarides.

Animals↗

Molecular comparison of retroviruses associated with human and simian AIDS.

Infectious retrovirus(es) associated with the human (LAV, HTLV-III, ARV) and simian (SAIDS-1) acquired immune deficiency syndrome were compared by electron microscopy, immunofluorescence and immunoblotting techniques and by restriction endonuclease mapping of the viral genomes. The extracellular virus particles had similar type D morphology, but intracytoplasmic type A nucleoids were found only in SAIDS virus infected cells. Although the antigens of the three prototype AIDS viruses were similar, no cross-reactivity with the SAIDS virus was detected. Molecular hybridization and restriction enzyme analysis also revealed that the SAIDS and AIDS viruses were genetically unrelated. However, only minor differences, consistent with strain polymorphism, were found between the three AIDS virus isolates. Thus, the retroviruses associated with AIDS in macaques and humans are unique to each species.

Acquired Immunodeficiency Syndrome↗

Open study of clobazam in refractory epilepsy.

Clobazam is a 1,5-benzodiazepine reported to have a wide spectrum of antiepileptic activity and is associated with less neurotoxicity than the 1,4-benzodiazepines, nitrazepam and clonazepam. The effect of clobazam on seizure control and neurologic behavior was examined prospectively in 115 children (average age: 8.4 years) with intractable seizures. Eighteen children (16%) became seizure free and a further 35 (31%) demonstrated a greater than 90% decrease in seizure frequency. Tolerance to the antiepileptic effect of clobazam was observed in 30 of 79 children (38%) who demonstrated an initial improvement in seizure control. Complete tolerance was observed in 9 patients, partial tolerance in 9, and partial tolerance that responded to an increased dose of clobazam in 12. Seventy-two percent of patients reported improvement and 26% worsening in at least one parameter of neurologic function after beginning clobazam. The improvement in neurologic function correlated poorly with change in seizure control. Patients who discontinued 1,4-benzodiazepine (n = 37) had a greater improvement in attention span, alertness, balance, drooling, and mood compared to the remainder of the group. These data suggest that clobazam is effective in the treatment of children with a wide range of epilepsies and seizure types and support the clinical impression that clobazam is associated with less neurotoxicity than the 1,4-benzodiazepines.

Adolescent↗

Immunization against SIVmne in macaques using multigenic DNA vaccines.

All structural and regulatory genes of SIVmne were cloned into mammalian expression vectors to optimize expression in vitro and immunogenicity in mice. Macaca fascicularis were immunized four times with plasmid DNA (n = 4), or two DNA priming inoculations followed by two boosts of recombinant gp160 plus Gag-Pol particles (n = 4). Following intrarectal challenge with SIVmne, all macaques became infected. Three monkeys immunized with DNA alone maintained low plasma virus loads by 1 year post-challenge; the fourth exhibited high virus loads and significant CD4+ cell decline. Two of the DNA plus boost and three control macaques had high virus loads and associated CD4+ cell decline. Both vaccine protocols elicited antibodies and comparable helper T-cell proliferative responses to gp160. Cytokine mRNA levels in activated peripheral blood mononuclear cells (PBMC) taken at time of challenge suggested a dominant T helper (Th) 1 state in three DNA-immunized and one protein-boosted macaque, which correlated with low virus loads and high CD4+ cell counts post-challenge.

AIDS Vaccines↗