Structure of the repeating unit of acid polysaccharide from Alteromonas sp. 4MS17

An acidic polysaccharide from Alteromonas sp. 4MC17 is built up of trisaccharide repeating units containing D-glucose, D-mannose and D-galacturonic acid residues. On the basis of methylation studies, 1H and 13C NMR-spectroscopy data, including two-dimensional homonuclear correlation spectroscopy and nuclear Overhauser effects, the following structure was suggested for the polysaccharide repeating unit: -->4)-beta-D-Glcp-(1-->4)-beta-D-GalpA-(1-->4)-beta-D-Manp-( 1-->.     

Frequent clones of p53-mutated keratinocytes in normal human skin

The multiple genetic hit model of cancer predicts that normal individuals should have stable populations of cancer-prone, but noncancerous, mutant cells awaiting further genetic hits. We report that whole-mount preparations of human skin contain clonal patches of p53-mutated keratinocytes, arising from the dermal-epidermal junction and from hair follicles. These clones, 60-3000 cells in size, are present at frequencies exceeding 40 cells per cm2 and together involve as much as 4% of the epidermis. In sun-exposed skin, clones are both more frequent and larger than in sun-shielded skin. We conclude that, in addition to being a tumorigenic mutagen, sunlight acts as a tumor promoter by favoring the clonal expansion of p53-mutated cells. These combined actions of sunlight result in normal individuals carrying a substantial burden of keratinocytes predisposed to cancer.     

HIV arthritis

Whether reexposure of varicella-immune persons to varicella-zoster virus would protect against or predispose to development of zoster was analyzed. The rate of zoster in 511 leukemic recipients of varicella vaccine who had 1 or > 1 dose of varicella vaccine and in those who did or did not have a household exposure to varicella was determined. A Kaplan-Meier life-table analysis revealed that the incidence of zoster was lower in those given > 1 dose of vaccine (P < .05). A Cox proportional hazards analysis showed that both household exposure to varicella and receipt of > 1 dose of vaccine were highly protective (P < .01) against zoster. Thus, the risk of zoster is decreased by reexposure to varicella-zoster virus, either by vaccination or by close exposure to varicella.     

The secondary structure of phospholamban: a two-dimensional NMR study

Phospholamban (PLN) is an intrinsic membrane protein of 52 amino acids which regulates the Ca2+ pump of the sarcoplasmic reticulum of heart, slow-twitch and smooth muscle (SR): it is normally assumed to exist in the membrane as a homopentamer. A monomeric analogue of phospholamban PLN(C41F), in which Cys41 was replaced by a Phe, was synthesized and its conformation studied by 1H NMR spectroscopy in a 1:1 mixture of chloroform/methanol. Most of the resonances in the 1H NMR spectra were assigned. The work has shown that the C-terminal hydrophobic portion forms a very stable alpha-helix. The hydrophilic N-terminal part adopts an alpha-helix configuration which is much less stable except for the stretch containing the phosphorylation sites.     

Haemolytic activity of Aeromonas species isolated in Libya

Twenty seven Aeromonas strains (5A. hydrophila, 8A. sobria and 14A. caviae) isolated from children with diarrhoea and 34 Aeromonas strains (9A. hydrophila, 7A. sobria an 18A. caviae) isolated from children without diarrhoea were tested from haemolysin production. The results obtained showed that haemolysin production using human, horse or sheep erythrocytes was significantly associated with A.hydrophila and A sobria but not with A.caviae, regardless of whether these strains were isolated from children with or without diarrhoea. Human or horse rather than sheep erythrocytes are recommended for use in the haemolysin assay.     

Thrombolysis for evolving myocardial infarction in a rural primary care clinic

Early thrombolytic therapy gives maximum benefit in acute myocardial infarction. In remote rural areas with no mobile intensive care service there is a significant delay between onset of symptoms and administration of thrombolytic therapy which has a critical impact on revascularization. Thrombolytic therapy with streptokinase 1,500,000 U was given in a primary care rural clinic to 2 patients with evolving myocardial infarction 45-50 minutes from onset of symptoms. In both patients, who were transported to hospital after the therapy, there were clinical signs of reperfusion. There were no complications during treatment or transportation. We conclude that thrombolytic therapy given for evolving myocardial infarction in a rural primary care clinic is possible and safe.     

Oncogene rearrangement in non-Hodgkin's lymphoma with a 14q+ chromosome of unknown origin

Southern blot analysis was performed with a panel of DNA probes to detect rearrangements of c-myc, bcl-1, bcl-2 and bcl-3 in 14 cases of B-cell non-Hodgkin's lymphoma (NHL) with a clonal cytogenetic rearrangement involving the chromosome 14q32 locus and no known donor chromosome [t(14;?)(q32;?)]. In our experience, 21% of all chromosomal abnormalities involving the 14q32 locus in B-cell NHL are of this type. We found oncogene rearrangements in five of the 14 cases: bcl-1 rearrangement on one mantle zone lymphoma, bcl-2 rearrangements in two follicular lymphomas, and c-myc rearrangements in two small noncleaved cell lymphomas. We conclude that a 14q32+ abnormality of unknown origin is a relatively frequent karyotypic finding in B-cell NHL. In one third of the cases, known oncogenes that have been previously described in reciprocal translocations involving the immunoglobulin heavy chain locus were shown to be involved in the 14q32+ abnormality. The translocations in the other cases are likely to have involved one of the above oncogenes with breakpoints not revealed by the probes employed, other known oncogenes, or oncogenes that have not yet been identified.