The influence of verapamil on serum digoxin concentration

The effect of verapamil on the pharmacokinetics of digoxin was studied in 49 patients with chronic atrial fibrillation. A dose of 240 mg/day of verapamil was given to the patients who were receiving a stable dose of digoxin. Serum digoxin levels rose from 0.76 +/- 0.54 ng/ml (mean +/- SD) to 1.31 +/- 0.54 ng/ml during verapamil treatment (p less than 0.0005). This effect was dose-dependent, as shown in seven subjects who received 160 mg and then, 240 mg of verapamil: There was a stepwise rise in serum digoxin concentration from a control value of 0.60 +/- 0.11 ng/ml to 0.84 +/- 0.18 ng/ml and 1.24 +/- 0.40 ng/ml, respectively (p less than 0.01 for both steps). The effect of verapamil developed gradually within the first few days in seven subjects in whom serum digoxin concentration reached, within 7 days, 90% of the increase observed 14 days after onset of verapamil. Renal digoxin clearance decreased significantly (26.1 +/- 0.7 vs 55.1 +/- 12.3 ml/min, p less than 0.005) in six patients in whom serum digoxin concentration increased. It did not change in one patient in whom serum digoxin concentration was not influenced by verapamil. Creatine clearance did not change in any of these seven. The same effects on digoxin clearance were observed in three normal subjects. Among the 49 patients, verapamil resulted in the development of signs and symptoms that suggested digitalis toxicity in seven. Verapamil significantly increased serum digoxin concentration. The process is dose-dependent and gradual, and it is at least partially explained by reduced renal excretion without reduction in glomerular filtration. The dose of digoxin may need readjustment in patients who are concomitantly receiving verapamil.

Clinical use of oral verapamil in chronic and paroxysmal atrial fibrillation

We evaluated the effectiveness of oral verapamil therapy for control of ventricular rate in digitalized patients with atrial fibrillation (AF) with three clinical problems: chronic AF with rapid rate at rest (four patients), chronic AF with accelerated rate during modest exercise (five patients), and rapid rates during paroxysmal AF (four patients). Patients in the first two categories were evaluated both by open-label dosage titration and by a randomized, double-blind, cross-over protocol. In chronic AF with rapid rate of rest, there was a significant reduction in resting heart rate (from 125 +/- 7 to 87 +/- 14, P less than 0.01) and in peak exercise heart rate (from 162 +/- 33 to 126 +/- 25, P less than 0.01). In chronic AF with rapid rate during exercise, there was also a significant decrease in resting heart rate (from 90 +/- 7 to 66 +/- 4, P less than 0.01) and in peak exercise heart rate (from 126 +/- 19 to 101 +/- 15, P less than 0.01). These effects continued during longterm follow-up of one to 12 months (mean seven months). In patients with paroxysmal AF, verapamil slowed the ventricular response from 16- +/- 24 to 72 +/- 4 P less than 0.01) with only some amelioration of symptoms. Therapy was well tolerated despite a high prevalence (seven of 13 patients) of radiographic cardiomegaly (cardiothoracic ratio greater than 0.55). We conclude that verapamil is a safe and useful drug for control of ventricular rate in digitalized patients with chronic and paroxysmal AF.

Anthelmintic activity of mebendazole against induced and naturally occurring helminth infections in cats

A formulation of mebendazole was used to determine the optimal dosage level against induced and/or naturally occurring infections of Toxocara cati, Ancylostoma tubaeforme, and Taenia taeniaeformis in cats. Amounts of 11 mg/kg of body weight/day or 22 mg/kg/day were given for 2, 3, or 4 days. Feces were collected for 7 days and were examined for expelled parasites. Cats were necropsied to recover retained parasites. A regimen of 22 mg/kg/day for 3 days was determined to be optimal with efficacies of 100%, 99%, and 50% against T cati, A tubaeforme, and Taenia taeniaeformis, respectively.

Pilot trials on the treatment of Dermatobia hominis infections in cattle with closantel

The therapeutic and prophylactic activities of closantel given to calves inoculated with larvae of Dermatobia hominis were studied. Calves (n = 9 principals, plus 3 nontreated controls) were given closantel at different dosages (8 to 12.5 mg/kg) and schedules of treatment. The largest dosage of closantel (12.5 mg/kg) had the most efficacious therapeutic activity (97.3%). Prophylactic activity was also seen in calves given the drug before they were experimentally inoculated.

[Kidney and osseous responsiveness to PTH in a case of pseudohypoparathyroidism (author's transl)]

A case of pseudohypoparathyroidism is described, finding in addition to the typical clinical data described in the literature an all almost total atrophy of the minor lips and clitoris, a perforated hymen and a "paradoxical" increase of convulsions with anticomicial treatment. Study of response of urinary phosphates and AMPc to PTH, was negative (Drezner type I). Osseous response to PTH was negative (Frame type I pseudohypoparathyroidism). Pathogenic possibilities are discussed.

Comparative anthelmintic efficacy of two schedules of mebendazole treatment in dogs

Two schedules of anthelmintic oral treatment, using mebendazole powder, were compared in 73 dogs naturally infected with common helminth intestinal parasites. Mebendazole powder was administered to 26 dogs at doses of 22 mg/kg once daily for 3 days and was compared with the same dose given only daily for 5 days into 23 dogs. The 24 other dogs were kept as controls and received a placebo treatment for 5 days. Efficacy results for the 3-day treatment schedule of mebendazole were as follows: Toxocara canis, 100%; Uncinaria stenocephala, 100%; Ancylostoma caninum, 99.4%; Trichuris vulpis, 100%; and Taenia pisiformis, 93.9%. Mebendazole powder given on the 5-day treatment schedule was 100% efficacious against the foregoing parasites. Anthelmintic efficacy against Dipylidium caninum was not detected in either schedule of treatment.

Laminated Diatomaceous Sediments from the Guaymas Basin Slope (Central Gulf of California): 250,000-Year Climate Record

During Deep Sea Drilling Project-International Program of Ocean Drilling leg 64, December 1978 to January 1979, the initial test of the Deep Sea Drilling Project's hydraulic piston corer obtained an almost undisturbed section from a 152-meter hole into the sediments of the oxygen minimum zone at a depth of 655 meters along the Guaymas slope in the central Gulf of California. The section records variations in climate, productivity, and circulation for more than 250,000 years of Late Pleistocene to Holocene history with recordings of seasonal variations in these parameters in the laminated sections.

[Myocardial fibrosis in Shwachman's syndrome (author's transl)]

A case of a child affected by Shwachman's syndrome with a chronic diarrhea, cyclic neutropenia and bone defects is described. The child died at the age of eight months from an acute cardiac failure which showed analytical alterations compatible to an acute myocardial infarction. Pathologic study showed a pancreatic lipomatous hypoplasia, myocardial fibrosis and chondrometaphyseal dysplasia. Main hypothesis that relate pancreatic pathology and development of myocardial fibrosis are discussed, although there is a lack of definitive evidence for confirming such relation.

[Urea half-live as index of renal failure in hypertonic dehydration (author's transl)]

Evolution of uremic half-time in 27 infants with hypertonic dehydration is studied. Authors establish three groups in accordance with duration of uremic half-time: 1st: less than 24 hours: 5 infants. 2nd: More than 24 hours without renal or uremic pathology: 12 infants. 3rd: More than 24 hours with renal or uremic pathology: 10 infants. Utility of this parameter is discussed, as well as its physiologic bases. The existence of 2nd group makes the value of this control as an organic of functional renal index uncertain.

[Hyperglycemia in hypertonic dehydration (author's transl)]

Fourteen patients who developed hyperglycemia with hypertonic dehydration are reviewed, and compared to a control group of twenty-four dehydrated infants without hyperglycemia. The threshold of hyperglycemia was considered at 125 mg. %. The relationship between hyperglycemia and degree of formula concentration, incidence of shock and water and solute metabolism chemistry are analysed. The different theories about hyperglycemia in the course of hypertonic dehydration are discussed. Because of the negativity of other factors, authors suggest that the most important factor in hyperglycemia may be the ionic alteration of the cell.

Experimental muscular amebiasis in hamsters as a biological model

Trophozoites of Entamoeba histolytica maintained in vitro in Pavlova's medium were inoculated by deep intramuscular injection into the proximal left hindleg of hamsters. Thioglycollate medium was utilized as a successful vehicle to induce the infection. The invasion of the muscular tissue by the vegetative forms caused the formation of abscesses with great destruction of muscular fibers. The lesions were limited to the muscular tissue of the femoral area. The number of trophozoites, the medium of thioglycollate as a vehicle, the volume of the inoculum and the trauma caused by the needle were important elements in the evolution of the muscular amebic abscesses. A limited trial of the amebicidal activity of metronidazole utilizing the amebic intramuscular infection was also performed.

Normotensive hyperreninemia in systemic lupus erythematosus. An indicator of tubular dysfunction

High plasma renin activity (PRA) was found in 16 of 42 randomly selected nonuremic systemic lupus erythematosus (SLE) patients. Mild hypertension was present in 3 of the 16.6 high-PRA and 10 normal-PRA patients were admitted to a metabolic ward. Salt restriction produced a disproportionate rise in both PRA and aldosterone, a decrease in glomerular filtration rate (GFR) and a slightly greater negative sodium balance in the group with high PRA. Potassium excretion was less than intake in both groups. Balance studies were performed in 6 additional high-PRA patients before and during indomethacin administration (150 mg/24 h). PRA and aldosterone were markedly suppressed by indomethacin. UnaV was significantly greater than in the control period despite of the 28% reduction in GFR. These results suggest that high PRA is secondary to impaired distal tubular sodium reabsorption. Such a defect could be responsible for the relatively low frequency of hypertension in lupus nephritis.