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Biomedical subjects

M Clark

Publications and source records attributed to M Clark.

At least 271 records · Page 15Linked to original sources
PubMed1986

Atrial natriuretic factor in normal subjects and heart failure patients. Plasma levels and renal, hormonal, and hemodynamic responses to peptide infusion.

We investigated atrial natriuretic factor (ANF) in humans, measuring plasma immunoreactive (ir) ANF (in femtomoles per milliliter), and renal, hormonal, and hemodynamic responses to ANF infusion, in normal subjects (NL) and congestive heart failure patients (CHF). Plasma irANF was 11 +/- 0.9 fmol/ml in NL and 71 +/- 9.9 in CHF (P less than 0.01); the latter with twofold right ventricular increment (P less than 0.05). In NL, ANF infusion of 0.10 microgram/kg per min (40 pmol/kg per min) induced increases (P less than 0.05) of absolute (from 160 +/- 23 to 725 +/- 198 mueq/min) and fractional (1-4%) sodium excretion, urine flow rate (from 10 +/- 1.6 to 20 +/- 2.6 ml/min), osmolar (from 3.2 +/- 0.6 to 6.8 +/- 1.2 ml/min) and free water (from 6.8 +/- 1.6 to 13.6 +/- 1.6 ml/min) clearances, and filtration fraction (from 20 +/- 1 to 26 +/- 2%). Plasma renin and aldosterone decreased 33% and 40%, respectively (P less than 0.01). Systolic blood pressure fell (from 112 +/- 3 to 104 +/- 5 mmHg, P less than 0.05) in seated NL; but in supine NL, the only hemodynamic response was decreased pulmonary wedge pressure (from 11 +/- 1 to 7 +/- 1 mmHg, P less than 0.05). In CHF, ANF induced changes in aldosterone and pulmonary wedge pressure, cardiac index, and systemic vascular resistance (all P less than 0.05); however, responses of renin and renal excretion were attenuated. ANF infusion increased hematocrit and serum protein concentration by 5-7% in NL (P less than 0.05) but not in CHF.

Adult↗
PubMed1986

Chronic intestinal ischemia: diagnosis and therapy.

Splanchnic arteriosclerosis is common among the elderly population, but intestinal angina is distinctly a rare entity. Extensive and efficient mesenteric collateral pathways make development of intestinal angina unlikely unless at least two major vessels exhibit hemodynamically important stenoses. Herein we describe the surgical management of 17 patients with chronic intestinal ischemia. The patients most commonly had postprandial pain and lost significant weight; angiography, including lateral aortography, confirmed the diagnosis. An average of 2.5 vessels in these 17 patients were arteriosclerotically involved. These 17 patients underwent 20 major splanchnic artery reconstructions altogether (average, 1.2 vessels per patient) for relief of symptomatic intestinal ischemia. Arterial reconstructions (16 bypass procedures and 4 endarterectomies) were undertaken with either autogenous saphenous vein (10 vessels) or Dacron prosthetics (6 vessels). Revascularizations involved the superior mesenteric artery (six patients), hepatic artery (three patients), splenic artery (seven patients), and inferior mesenteric artery (four patients). Five deaths occurred after operation, two early and three late, all from myocardial infarctions. All patients who survived have been relieved of their pain, and there has been no recurrence. The average length of follow-up has been 60.9 months and repeat angiography in six patients at intervals of up to 5 years has shown no evidence of revascularization occlusion.

Aged↗
PubMed1985

Acute myelomonocytic leukemia (M-4 subtype) with abnormal marrow eosinophilia and a normal chromosome 16.

A variety of chromosome 16 abnormalities, including inversion, deletion, and translocation in patients with acute myelomonocytic leukemia and abnormal marrow eosinophilia have been reported recently. The authors have identified an AMML patient who had a normal karyotype in 50 metaphases. In particular, chromosome 16 was closely examined for abnormality and was found to be entirely normal. In addition, the authors describe new cytochemical and ultrastructural features of the associated abnormal eosinophils.

Antigens, Surface↗
PubMed1985

Therapeutic potential of monoclonal antibodies to the leukocyte-common antigen. Synergy and interference in complement-mediated lysis.

A series of rat monoclonal antibodies against the human leukocyte-common antigen were isolated and, by means of competitive binding assays with purified antigen, two distinct groups were defined that recognize different epitopes of the molecule. None of these antibodies were lytic with human complement, but when antibodies against each of these two epitopes were used in combination, synergistic lysis with human complement could be obtained. Synergistic lysis was only seen when each antibody of the pair was of the IgG2b subclass. IgG2a antibodies could not synergize, and in fact could interfere with lysis obtained by the pair of IgG2b antibodies. Although synergy has so far only been studied for rat monoclonal antibodies we also show that it is possible with mouse antibodies or with combinations of mouse and rat antibodies. The information about the principles of synergy and its interference should provide a rationale for using well-planned cocktails of monoclonal antibodies for therapy rather than a shotgun polyclonal antiserum.

Animals↗
PubMed1985

Percutaneous transcatheter embolization of injuries to the profunda femoris artery: a case report.

Traumatic injury to the middle and distal thirds of the profunda femoris artery can be extremely difficult to surgically repair. The present article outlines an alternative form of treatment in which angiotherapeutic techniques of embolization are used in such an injury. A survey of the literature indicates that this may be the preferred method of therapy with lesions in this difficult area to surgically approach.

Adult↗
PubMed1985

Therapeutic potential of rat monoclonal antibodies: isotype specificity of antibody-dependent cell-mediated cytotoxicity with human lymphocytes.

The ability of rat monoclonal antibodies to promote antibody-dependent cell-mediated cytotoxicity with human effector cells was tested by using a variety of antibodies against different human and mouse leukocyte antigens. It was found that only IgG2b antibodies were effective. This isotype has already been shown to be efficient in fixing human complement, which suggests that among rat monoclonal antibodies, the IgG2b subclass might be a good choice for attempts at serotherapy. Further studies with other antibody-mediated effector mechanisms as well as suitable clinical trials are merited.

Animals↗