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Biomedical subjects

V Payne

Publications and source records attributed to V Payne.

9 recordsLinked to original sources
PubMed2004

Mast cell tryptase: a review of its physiology and clinical significance.

Mast cells, which are granulocytes found in peripheral tissue, play a central role in inflammatory and immediate allergic reactions. beta-Tryptase is a neutral serine protease and is the most abundant mediator stored in mast cell granules. The release of beta-tryptase from the secretory granules is a characteristic feature of mast cell degranulation. While its biological function has not been fully clarified, mast cell beta-tryptase has an important role in inflammation and serves as a marker of mast cell activation. beta-Tryptase activates the protease activated receptor type 2. It is involved in airway homeostasis, vascular relaxation and contraction, gastrointestinal smooth muscle activity and intestinal transport, and coagulation. Serum mast cell beta-tryptase concentration is increased in anaphylaxis and in other allergic conditions. It is increased in systemic mastocytosis and other haematological conditions. Serum beta-tryptase measurements can be used to distinguish mast cell-dependent reactions from other systemic disturbances such as cardiogenic shock, which can present with similar clinical manifestations. Increased beta-tryptase levels are highly suggestive of an immunologically mediated reaction but may also occur following direct mast cell activation. Patients with increased mast cell beta-tryptase levels must be investigated for an allergic cause. However, patients without increased mast cell tryptase levels should be investigated if the clinical picture suggests severe anaphylaxis.

Anaphylaxis↗
PubMed1997

Clinical results with electrophysiologist-implanted cardioverter-defibrillators.

With the advent of nonthoracotomy leads and smaller devices, implantation techniques for implantable cardioverters defibrillators (ICDs) have been simplified. We reviewed the outcome of pectoral ICD implantation by electrophysiologists in 51 consecutive patients, 47 males and 4 females, mean age 60 +/- 12 years, presenting with aborted sudden cardiac death (14) and drug refractory hypotensive ventricular tachycardia (37). Patients were implanted with either the PCD Jewel 7219D (37) or 72197C (14) Medtronic pectoral ICDs. The mean operative time was 98 +/- 31 minutes. There was no operative mortality. Complications occurred in 2 (4%) patients: right ventricular lead dislodgement requiring lead repositioning occurred in 1 patient, and 1 patient treated with anticoagulants, who had received a subcutaneous patch lead, developed a hematoma not requiring surgical reintervention. The mean defibrillation threshold was 18.6 +/- 5.5 J, but was significantly lower for the 7219C (14.1 +/- 5.0 J) compared to the 7219D (20.6 +/- 4.4 J) device, P = 0.0001. A two-lead system consisting of a right ventricular electrode (RVA) and a superior vena caval lead (SVC) was utilized in 29, RVA/SVC-subcutaneous patch in 5 and active can in 17 patients. Patients were discharged after 4.3 +/- 3 days: The procedure time was significantly shorter for the 7219C device (79.7 +/- 18.9 vs 105.2 +/- 32.8 minutes., P = 0.0035). Over the follow-up period of 8 +/- 5 (range 1-20) months, 26% patients received appropriate therapy (95% antitachycardia pacing, 5% shock). Concomitant antiarrhythmic therapy was utilized in 41% of patients. Ninety-eight percent of patients are alive. One patient died of congestive heart failure. Clinical results with electrophysiologist-implanted pectoral ICDs demonstrate low morbidity and no operative mortality in this clinical series and lower DFTs and shorter procedure times may be achieved with 7219C (active can) device.

Anticoagulants↗
PubMed1992

Mutagenic activity of a series of synthetic and naturally occurring heterocyclic amines in Salmonella.

26 synthetic and naturally occurring heterocyclic amines were tested in the Salmonella/microsome assay (Ames test) using tester strains TA98 and TA100 in the presence of an Aroclor-induced rat-liver S9 fraction. 9 of the compounds were protein-pyrolysis products which had previously been shown to be mutagenic. Mutagenic potencies similar to previously reported values were demonstrated for these compounds with the exception that Trp-P-1 was only mutagenic in strain TA98 in our study, although it had previously been reported to be weakly mutagenic in strain TA100. 17 structurally diverse heterocyclic amines were synthesized and tested for mutagenicity. The structural diversity of these synthetic heterocyclic amines will enhance the sensitivity of future quantitative structure-activity relationship (QSAR) studies by demonstrating the structural characteristics essential for mutagenicity. The results of this study provide a large data base for the mutagenicity of this important class of compounds.

Amines↗
PubMed1990

Bacterial lipopolysaccharide enhances polymorphonuclear leukocyte function independent of changes in intracellular calcium.

Bacterial lipopolysaccharide (LPS) enhanced expression of C3bi receptors (CR3), phagocytosis of opsonized bacteria, and subsequent hydrogen peroxide (H2O2) production by human polymorphonuclear leukocytes (PMNs). The role of changes in intracellular calcium concentration ([Ca2+]i) in LPS-induced priming was examined by determining the effect of modulators of intracellular calcium on enhanced PMN function, determining the ability of calcium ionophores to reproduce the effects of LPS, and measuring PMN [Ca2+]i following addition of LPS. Inhibition of intracellular calcium-dependent processes with TMB-8 or quin-2 blocked all three measures of LPS-induced priming. LPS did not stimulate an increase in [Ca2+]i, and calcium ionophores failed to reproduce the effect of LPS. Maintenance of [Ca2+]i is necessary for LPS priming, but an increase in [Ca2+]i is not a component of the signal transduction pathway leading to PMN priming by LPS.

Aminoquinolines↗
PubMed1984

The effect of iron supplements on pregnancy in rats given a low-zinc diet.

Female Wistar rats were given an adequate-zinc (60 micrograms/g) or low-Zn (7 micrograms/g) diet for a minimum of 2 weeks and then mated. They were then either continued on the same diets (+Zn -Fe or -Zn -Fe) or given similar diets supplemented with four times the normal level of iron (+Zn +Fe or -Zn + Fe). The day before parturition they were killed and the fetuses removed and analysed. There were no differences in numbers of fetuses or the number of resorption sites. In the absence of Fe supplementation, the mean fetal wet weight was significantly less (P less than 0.05) in the low-Zn group but there was no effect of Zn in the two Fe-supplemented groups. The addition of Fe significantly decreased (P less than 0.05) the mean fetal wet weight in the adequate-Zn groups but had no effect in the low-Zn groups. There were no differences in fetal dry weight, fat, protein or DNA content. Both Fe-supplemented groups produced fetuses of higher Fe concentration (P less than 0.01), and mothers with higher bone Fe-concentration (P less than 0.01) compared with the non-supplemented groups. The low-Zn groups produced fetuses of lower Zn concentration (P less than 0.001) than the adequate-Zn groups but there was no effect on maternal bone Zn concentration. It was concluded that Fe-supplements did not adversely affect fetal growth from mothers given a low-Zn diet, but the addition of Zn to the unsupplemented diet increased fetal wet weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Pulmonary sequestration in children: a twenty-five year experience.

Pulmonary sequestration occurs when some disturbance produces a cystic mass of nonfunctioning lung tissue which lacks normal communication with the tracheobronchial tree. In most cases the sequestered pulmonary tissue receives its blood supply from anomalous systemic vessels. This paper considers 15 children, 11 boys and four girls, ranging in age from one day to 14 years, with ten extralobar sequestrations and five intralobar pulmonary sequestrations. Although roentgenographic examination of the chest may suggest the diagnosis, conclusive diagnosis can only be obtained by arteriography and/or surgical exploration. Arteriography is strongly advocated in all cases, not only for its diagnostic value, but for its preoperative localization of the aberrant blood vessels that are the major technical concern to the surgeon.

Adolescent↗