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Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 937 records · Page 52Linked to original sources
PubMed1989

Cells of the monocyte-macrophage series in peripheral blood and synovial fluid in inflammatory arthritis. A preliminary study of cellular phenotype.

The phenotype of peripheral blood and synovial fluid cells of the monocyte-macrophage series was studied by FACS to extend previous immunohistological observations made in synovial membranes. The results of this preliminary study suggest that changes can be found in peripheral blood monocytes which might influence diapedesis and interaction with immune complexes. The phenotype of synovial fluid macrophages does not provide evidence of advanced maturation and is most consistent with rapid recruitment of the cells into the joint. Synovial fluid macrophages showed increased expression of the leukocyte integrin p150.95 which functions as an adhesion molecule and complement receptor. This is consistent with our previous observation of upregulation of this molecule on Mph in inflamed synovial membranes. This preliminary study has indicated areas for more detailed analysis with the aim of defining sequential changes in macrophage expression of functional surface molecules in inflammatory arthritis.

Adult↗
PubMed1989

Marketing backgrounds and activities of community mental health center CEOs.

More than 300 directors of community mental health centers responded to a survey concerning their marketing training and the marketing activities in which their centers had been engaged. Formal marketing training was found to be in the backgrounds of few of the respondents. The majority had not been engaged in a listing of marketing activities.

Adult↗
PubMed1989

Coagulation changes following hepatic revascularization during liver transplantation.

The coagulation changes during liver transplantation have been studied in 14 selected patients. Blood usage in all cases was limited to 8.5 liters, and the preoperative coagulation results were only minimally deranged. Bleeding during the operative procedure was easily managed in all cases. Nonetheless, even in this selected group of "low risk" patients, we have demonstrated that during the anhepatic phase and particularly following hepatic revascularization there is activation of both coagulation and fibrinolysis. These findings imply that if bleeding occurs following revascularization, in addition to the use of replacement blood products, treatment should be directed at reducing the consumptive coagulopathy and inhibiting fibrinolysis. We suggest as a first step antithrombin supplementation to maintain activity above 70%, and an antifibrinolytic agent, such as aprotonin, should be considered as adjuncts to therapy at revascularization.

Age Factors↗
PubMed1989

Release of atrial natriuretic factor with increasing absolute atmospheres of pressure in a hyperbaric chamber and reversal with oxygen therapy.

Diving is associated with a marked diuresis which can be accurately reproduced in a hyperbaric chamber where the pressure of a specific depth can be precisely controlled. The present investigation was designed to determine if the diuresis observed with diving is associated with increased release of a new diuresis-producing hormone, atrial natriuretic factor (ANF). Seven experienced divers (3 men and 4 women; average age of 31 years) had their circulating concentration of atrial natriuretic factor measured at 1, 2 and 3 atmospheres of absolute pressure (ATA) in a monoplace hyperbaric chamber while breathing air. With the simulated dive to 33 feet (2 ATA), the circulating concentration of ANF increased 3-fold and at a depth of 66 feet (3 ATA) ANF increased 6-fold over the concentration at 1 ATA. With the addition of 100% oxygen while at depths of 33 and 66 feet, the concentration of ANF immediately decreased to its pre-dive concentration and remained there with further decompression to surface air and removal of oxygen supplementation. Thus, the increased release of ANF with depth may help to explain the diuresis observed with diving.

Adult↗
PubMed1989

Abnormalities of cytoplasmic Ca2+ in platelets from patients with uremia.

Uremic patients have a hemorrhagic tendency, often associated with prolonged bleeding times and decreased platelet function in vitro. Whether these defects result from abnormalities in plasma factors affecting platelet activity, platelet surface receptors, intracellular platelet mediators, or other aspects of platelet behavior is unknown. To examine the possibility that the abnormality in platelet function may result from aberrations in Ca2+ homeostasis, blood was obtained from 29 patients with severe uremia. The platelets were washed, loaded with the Ca2+ -sensitive probes indo-1 and aequorin, gel-filtered, and resuspended in either plasma or buffer. Of the 29 patients, seven had template bleeding times prolonged to 11 minutes or more, but platelet aggregation in plasma was not consistently impaired in these patients. However, in aequorin-loaded platelets from the patients with long bleeding times, the highest elevation of cytoplasmic calcium [( Ca2+]i) in response to the Ca2+ ionophore A23187, arachidonate, adenosine diphosphate (ADP), or epinephrine was lower than that seen in platelets from both uremic patients with less prolonged bleeding times and normal volunteers. The reduced [Ca2+]i response was associated with decreased aggregation of gel-filtered platelets suspended in buffer. Suspending washed aequorin-loaded uremic platelets in normal plasma for 20 minutes did not reverse the decreased agonist-induced rise in [Ca2+]i; platelets from a normal donor resuspended in uremic plasma aggregated and produced a normal increase in [Ca2+]i in response to agonists. We conclude that the platelet defect seen in some patients with uremia is associated with a decreased rise in platelet [Ca2+]i after stimulation and that this is a manifestation of an intrinsic platelet defect.

Aequorin↗
PubMed1989

Lack of toxicity of a topical recombinant interferon alpha.

We evaluated the potential ocular surface toxicity of a recombinant interferon-alpha (IFN alpha) preparation on rabbit eyes. Topical application of this interferon (1 x 10(6) U/day in each eye) for 6 weeks produced no discernible conjunctival or corneal abnormalities on clinical, histopathologic, or ultrastructural evaluations. We believe that this recombinant IFN alpha preparation is not toxic to the ocular surface of rabbits.

Animals↗
PubMed1988

MIC2: a human pseudoautosomal gene.

MIC2 and XGR are the only known pseudoautosomal genes in man. MIC2 encodes the 12E7 antigen, a human cell-surface molecule of unknown function. XGR regulates, in cis, the expression of the XG and MIC2 genes. DNA probes derived from the MIC2 locus have been used in the construction of a meiotic map of the pseudoautosomal region and a long range restriction map into the X- and Y-specific chromosome domains. MIC2 is the most proximal marker in the pseudoautosomal region and recombination between the sex chromsomes only rarely includes the MIC2 locus. Our long-range restriction maps and chromosome walking experiments have localized the pseudoautosomal boundary within 40 kilobases adjacent to the 3' end of the MIC2 gene. The same maps have been used to predict the chromosomal location of TDF.

Amino Acid Sequence↗
PubMed1988

Role of phenylalanine-82 in yeast iso-1-cytochrome c and remote conformational changes induced by a serine residue at this position.

A three-dimensional structural analysis of the reduced form of the Ser-82 mutant protein of yeast iso-1-cytochrome c has been completed to 2.8-A resolution. Replacement of Phe-82 with a serine residue results in conformational changes both near and remote from the mutation site. Those groups undergoing positional shifts near Ser-82 include Arg-13, Gly-83 and -84, and the CBB methyl of the heme group. Remote shifts are centered about the propionate of pyrrole ring A and principally involve Asn-52, Trp-59, and an internally buried water molecule, WAT-166. Placement of a serine side chain at position 82 also leads to the formation of a large solvent channel which substantially increases the solvent accessibility of the heme group. This would appear to account for the much lower reduction potential observed for this protein. The detrimental effect of Ser-82 on both the steady-state activity and the rate of electron transfer in complexation with cytochrome c peroxidase can also be interpreted in terms of the modified character of the region about the mutation site. The remote conformational changes observed appear to represent the equivalent of the initial conformational changes occurring as yeast iso-1-cytochrome c is converted to the fully oxidized state during an electron-transfer event. These results agree well with the proposal [Moore, G. R. (1983) FEBS Lett. 161, 171-175] that the trigger for conformational changes between oxidation states resides in the nature of the interactions between the heme iron atom and the pyrrole ring A propionate group.

Cytochrome c Group↗
PubMed1988

Activation of the A10 mesolimbic system by the sigma-receptor agonist (+)SKF 10,047 can be blocked by rimcazole, a novel putative antipsychotic.

This study evaluated with electrophysiological and behavioral techniques the ability of rimcazole, a novel putative antipsychotic and selective sigma-receptor ligand, to antagonize the stimulation of the mesocorticolimbic dopamine system by the sigma-agonist, (+)SKF 10,047. Rimcazole effectively blocked the (+)SKF 10,047-induced excitation of ventral tegmental dopamine neurons while having no effect on either spontaneous activity or apomorphine-elicited slowing of A10 firing. Rimcazole also antagonized the behavioral hyperactivity produced by (+)SKF 10,047, but not by d-amphetamine which is also mediated through the same mesolimbic dopamine pathway. These data provide further evidence that rimcazole's novel pharmacologic profile may involve a blockade of sigma-receptors on mesocorticolimbic dopamine neurons.

Animals↗
PubMed1988

Regulation of interprotein electron transfer by residue 82 of yeast cytochrome c.

Yeast iso-1-cytochrome c (Cc) mutants have been constructed with Phe, Tyr, Gly, Ser, Leu, and Ile at position 82, each with Thr substituted for Cys at position 102. Their long-range electron transfer with zinc-substituted cytochrome c peroxidase (ZnCcP) has been studied by two kinetic techniques. The charge-separated complex, [(ZnCcP)+,FeIICc] converts to [ZnCcP,FeIIICc] by a single, intracomplex electron transfer step that is not governed by "gating" through possible rapid dissociation of the complex or isomerization (for example, heme-ligand) by FeIICc subsequent to its formation from FeIIICc. In every variant with an aliphatic residue at position 82 of Cc, the rate of this electron transfer process is approximately 10(4) slower at approximately 0 degrees C than for the two variants with aromatic residues.

Amino Acids↗