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Biomedical subjects

A Pestana

Publications and source records attributed to A Pestana.

14 recordsLinked to original sources
PubMed1998

Allelic status of 1p, 14q, and 22q and NF2 gene mutations in sporadic schwannomas.

Schwannomas are common benign tumours of schwann cell origin, frequently found in patients with neurofibromatosis type 2 (NF2). Inactivation of the NF2 tumour suppressor gene appears to be a molecular event responsible for the development of up to 60% of cases, but no data are available on other superimposed secondary or alternative molecular abnormalities in those schwannomas lacking NF2 gene inactivation. We analysed 23 sporadic schwannomas for mutations in the NF2 gene and for the allelic status at 1p, 14q and 22q, as alterations of these genomic regions appear to be related to tumour progression in meningiomas, another NF2-associated neoplasm. Nine samples displayed allelic losses for markers on chromosome 22, and deletions at 1p were detected in two. No case showed losses for 14q. Three tumours displayed NF2 gene mutations, at exons 2, 7 and 12. Our results confirm that inactivation of the NF2 gene is a primary event in schwannoma development, and provide data suggesting that allelic loss at 1p may contribute to the pathogenesis of a small subgroup of this histological tumour type.

Alleles↗
PubMed1998

Six novel mutations in the NF2 tumor suppressor gene.

Six novel mutations were identified in the NF2 tumor suppressor gene in a panel of meningiomas and neurinomas. Screening was performed using a combination of single-strand conformation polymorphism and heteroduplex analyses on polymerase chain reaction-amplified DNA from tumors and matched peripheral blood lymphocytes. Mutations involved exons 2, 7, 11 and 12, and corresponded to three frameshift, one nonsense, one missense and one polymorphism.

Chromosome Aberrations↗
PubMed1994

Molecular analysis of chromosome 1 abnormalities in human gliomas reveals frequent loss of 1p in oligodendroglial tumors.

Alterations of the short arm of chromosome 1 are recurrently found in cytogenetic analysis of malignant gliomas, and deletions of 1p36-p32 region characterize at least the higher-grade tumors, glioblastoma multiforme. Molecular analysis of tumor-derived and normal genomic DNA from 57 cases of gliomas, using a panel of chromosome 1-specific DNA probes showed LOH in 16 tumors. Allelic losses on 1p were primarily restricted to glioblastoma multiforme (2/11) and to tumors with a major oligodendroglial component: grade II oligodendrogliomas (6/6), grade III anaplastic oligodendrogliomas (5/6) and grade II-III mixed oligo-astrocytomas (2/3). Losses for 1q markers were detected in only 1 tumor (glioblastoma multiforme). Our data suggest that anomalies of 1p primarily characterize oligodendrogliomas, whereas they are rare events in astrocytic tumors and indicate that a tumor-suppressor gene on 1p36-p32 is involved in the development of brain tumors with oligodendroglial differentiation.

Alleles↗
PubMed1990

A clinical trial comparing the safety and efficacy of a topical erythromycin-zinc formulation with a topical clindamycin formulation.

One hundred three patients with acne vulgaris were randomly designated to receive either a topical formulation of erythromycin plus zinc or a topical solution of 1% clindamycin phosphate (Cleocin-T). The patients treated themselves twice daily and were examined at 3, 6, 9, and 12 weeks after the start of therapy. By week 6 the overall severity grade was consistently lower and the percent reduction of severity, papules, pustules, and total comedones was higher in the erythromycin-zinc-treated group than in the clindamycin-treated group. In the 92 patients who completed this study (48 receiving erythromycin-zinc and 44 receiving clindamycin), no serious topical or systemic side effects were reported. Two patients, one from each treatment group, suffered mild irritation. One patient was withdrawn from the erythromycin-zinc-treated group. Results of patch tests were negative. The superiority of the erythromycin-zinc formulation may be due to the increased (4%) erythromycin concentration and/or the ability of 1.2% zinc acetate to enhance the product's activity.

Acne Vulgaris↗
PubMed1989

Cutaneous segmental neurofibromatosis.

A recent case of cutaneous segmental neurofibromatosis provided the opportunity to review the literature to better understand this rare disease. This cutaneous form of the disease usually appears only on the skin, without other systemic involvement; it is not inherited. Only 19 additional cases in the English literature could be found, three cases with extracutaneous manifestations; three cases were familial. The prognosis for this form of neurofibromatosis is excellent, but examination for evidence of systemic disease is indicated.

Abdomen↗
PubMed1987

Effect of ultraviolet light on topical minoxidil-induced hair growth in advanced male pattern baldness.

Nine healthy men with type IVa or Va male pattern baldness completed a 4-month single-blinded controlled pilot study designed to assess the effect of ultraviolet light (UVL) on topical minoxidil-induced hair growth. Subjects applied 2% topical minoxidil solution twice daily to their balding scalps and to one target area on the upper arm. These men, all of whom had either skin type II or III, were randomized to also receive either incremental doses of UVB or PUVA (topical psoralen) twice weekly to one side of their scalp and to a 2.5 cm target area on the nonminoxidil-treated upper ipsilateral arm. Vellus, nonvellus, and total hair counts were done in two 1-inch in diameter circular target areas in symmetric regions of the scalp and on each upper arm at regular intervals. All nine subjects had an increase in target nonvellus hair and a net loss of vellus hair in scalp target area treated with topical minoxidil. Concomitant UVL did not have a significant synergistic nor adverse effect on topical minoxidil-induced hair growth.

Adult↗
PubMed1985

Predictive value of HLA antigen for methotrexate-induced liver damage in patients with psoriasis.

For an investigation of a possible association between HLA antigens and postmethotrexate liver damage, the A, B, C, and Dr loci of the HLA antigens were determined in thirty-two patients with severe psoriasis who had been treated with methotrexate. There was no association between HLA antigens and increasing severity of liver disease in these patients. HLA-A3 was increased in frequency in the group of patients with the more severe liver damage but was not significant when corrected for the number of antigens tested. There appears to be no predictive value in HLA typing of psoriasis patients prior to starting methotrexate therapy.

Adult↗
PubMed1975

Acetylation of ribosome-associated proteins in vitro by an acetyltransferanse bound to rat liver ribosomes.

Incubation of rat liver ribosomes with [1-14-C]acetyl-coenzyme A results in the incorporation of [14-C]acetyl into a material insoluble in cold trichloroacetic acid. The acetyltransferase involved in the self-acetylation of ribosomes can be released by high salt washing of the ribosomes; the activity of the solubilized enzyme can be assayed using histones as acetyl acceptors. Electrophoretic analysis of acetylated risosomes or ribosomal proteins indicated that the acetyl radicals are associated with a group of relatively basic proteins, having molecular weights ranging from 10,000 to 45,000. Chromatographic analysis of the enzymatic hydrolsates of proteins extracted from acetylated ribosomes indicates that acetylation is mainly or exclusively NH2 terminal. Almost 80% of the acetyl proteins are released from the ribosomes by high salt treatment. Most of the acetyl radicals not solubilized by the high salt treatment were found in the 60S subunit, associated with a protein(s) having an apparent molecular weight of 43,000. This acetyl protein(s) was released from the 60S subunit by EDTA treatment and was found in a ribonucleoprotein complex having a bouyant density of 1.56.

Acetyltransferases↗
PubMed1975

Acetylation of nascent polypeptide chains on rat liver polyribosomes in vivo and in vitro.

Rat liver polyribosomes may be acetylated in vivo utilizing [3-H]acetate as precursor and in vitro with [14-C]acetyl-CoA. The in vitro acetylation occurs almost completely in the amino terminal position while the in vivo acetylation (after correction for isotopic exchange and incorporation of tritium into nonacetyl positions of amino acids) was distributed equally between the amino terminal groups of a number of amino acids and the epsilon-amino groups of internal lysine residues. At least 50% of the labeled acetyl groups introduced in vivo as well as in vitro could be removed from polysomes as puromycin polypeptides or -peptidyl-tRNA. The acetylated polypeptides have been resolved by gel filtration into two components, one with an average molecular weight of 20,000 and the other of 4000-7000. The results presented indicate that the N-terminal acetylation of nascent growing polypeptides is a post initiation event that occurs on small peptides (40-70 amino acid residues) and depends on the presence of a polysome-bound acetyltransferase which differs from other cytoplasmic acetyltransferases which catalyze predominately the acetylation of internal amino groups of proteins.

Acetates↗
PubMed1971

Cyclic adenosine 3',5'-monophosphate during glucose repression in the rat liver.

Intragastric administration of glucose inhibits the induction of serine dehydratase and tyrosine aminotransferase by glucagon in rat liver, but has no effect on the increase in hepatic adenosine 3',5'-monophosphate resulting from administration of glucagon. Thus, glucose repression in mammalian liver, unlike catabolite repression in microorganisms, appears to operate independently of the amounts of cyclic nucleotide in the cells.

Animals↗