An electrical potential difference (PD) is measured between maternal organism and fetus in the pregnant guinea pig. To investigate whether the PD is generated by active or passive forces these studies examined the temperature dependence of the PD in guinea pigs at 55-61 days gestation. Anesthesia was induced (ketamine, 44 mg/kg) and maintained (halothane, 1.5%) in 5 pregnant guinea pigs. The animals were subjected to alternating 1 hour periods of cooling and recovery, changing core body and intrauterine temperature about 5 degrees C. PD was monitored continuously with Ag/AgCl electrodes placed in the maternal abdominal cavity and the amniotic fluid. The resting PD (+/- SEM) was 24.1 +/- 2.8 mV. Analysis of covariance indicated that PD decreased slowly with time and increased significantly with lowered temperature. A second group of 4 guinea pigs was studied after beta blockade with propranolol (0.1 mg iv, repeated hourly). In this group the resting PD was 20.7 +/- 3.6 mV. The PD decreased gradually with time and decreased consistently during cooling. In the propranolol group the relation between PD and temperature yielded a calculated activation energy of 11.7 +/- 0.8 kcal/mol (Q10 = 1.9, 30-40 degrees C). These results are consistent with the hypothesis that at least some of the PD is generated by an energy-dependent electrogenic ion pump, or by selective passive diffusion of ions across a lipid membrane during which a significant energy barrier is overcome. They are not consistent with the generation of the PD exclusively by passive streaming of ions through water-filled channels. During cooling catecholamines are presumably released, favoring the generation of the PD.

Action Potentials↗

PubMed1988

Glucocorticoids in the management of vasculitis--a double edged sword?

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Animals↗

PubMed1979

Salicylates.

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Arthritis, Rheumatoid↗

PubMed1979

Nonsteroidal anti-inflammatory drugs.

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Anti-Inflammatory Agents↗

PubMed1978

Hyperuricemia in congenital heart disease.

Gout is rarely noted as a clinical problem in secondary polycythemia-- even if profound polycythemia exists, as in cyanotic congenital heart disease. A retrospective study of 81 patients with congenital heart disease was done to assess the incidence of hyperuricemia. Twenty of 46 patients with cyanotic congenital heart disease had serum levels of uric acid greater than 8 mg/dl. Thirteen of 16 (81%) cyanotic male patients more than 15 years old had serum levels greater than 8 mg/dl. For cyanotic patients, serum levels of uric acid were related directly to the degree of polycythemia (r = .44; P less than .02). Impaired renal function or drug therapy did not seem to account for the hyperuricemia. Because levels of uric acid greater than 10 mg/dl probably are nephropathic, many of these patients may be incurring subclinical uric acid nephropathy.

Adolescent↗

PubMed1977

Sporotrichosis arthritis: clinical features in seven patients.

A review of the clinical features of seven patients with sporotrichosis arthritis showed that six had joint infection without previous skin or lung involvement and that one with myelofibrosis had joint and skin infection. The average time from onset of joint symptoms to diagnosis was 25 months, resulting in joint damage that required arthrodesis in four patients. Tissue from open synovial biopsy was superior to synovial fluid for obtaining a positive culture; concomitant synovial fluid and synovial tissue cultures were superior to either one alone. Granulomatous inflammation was seen in synovial tissue in six patients biopsied. Amphotericin B with surgical debridement of the affected joint was successful treatment in four patients. Although an uncommon cause of joint disease, sporotrichosis arthritis may go unrecognized and mimic other forms of arthritis, resulting in irreparable damage in an otherwise curable form of arthritis.

Adult↗