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Biomedical subjects

J Harrison

Publications and source records attributed to J Harrison.

At least 253 records · Page 14Linked to original sources
PubMed1979

Ontogeny of bovine hemostasis.

Ontogeny of selected hemostatic system components was studied in 120 bovine fetuses which had been divided into eight monthly gestational age groups. Fetal blood was subjected to the following tests: platelet count, partial thromboplastin time, prothrombin time, thrombin time, fibrinogen quantitation, and assays for prothrombin and factors V and VIII. Platelet numbers corresponding to adult numbers were in fetal blood at least as early as gestation day 60, and their numbers varied only slightly thereafter. Bovine blood was incapable of in vitro coagulation at gestation day 90, with all samples coagulating by gestation day 150. Fetal coagulation screening test times (partial thromboplastin time, prothrombin time, and thrombin time) shortened during gestation and were near times of adults at birth. Of the four individual coagulation factors tested, only factor VIII reached adult values in the fetus in utero. Amounts of fibrinogen, prothrombin, and factors V and VIII in the neonate exceeded that of normal adult cattle.

Animals↗
PubMed1978

Neural factors contribute to atherogenesis.

Electron microscopic evidence of early atherogenic changes in the aorta and coronary arteries was obtained in normal fed, conscious, unrestrained rats receiving electrical stimulation in the lateral hypothalamus for periods of up to 62 days. Hypertension and hypercholesterolemia were not etiologic factors. In view of recent observations concerning neuropsychological mechanisms in human ischemic heart disease, the findings raise the possibility that the human central nervous system has a role in the development of atherosclerotic lesions.

Animals↗
PubMed1978

Plasmodium knowlesi malaria in the Rhesus monkey.

Twelve Rhesus monkeys were inoculated intravenously with about 500 000 malaria parasites, Plasmodium knowlesi. Acute hemolysis occurred 5 days later, and all animals died on the 6th or 7th day after inoculation. All organs were gray-green to gray-brown because of deposition of hemoglobin and malaria pigments. This deposition was particularly striking in the lung, brain, abdominal fat and serous surfaces. Microscopic changes indicative of acute hypoxia were found in the liver (centrilobular necrosis) and kidneys (acute tubular necrosis). Terminal intravascular coagulopathy was evidenced by widely distributed, recently formed, fibrin thrombi.

Animals↗
PubMed1977

Metabolic balance studies in patients with Paget's disease receiving salmon calcitonin over long periods.

Metabolic balance and calcium kinetic studies were performed in four patients with Paget's disease before treatment with salmon calcitonin and during the early and late stages of the treatment, which lasted 9 to 19 months, A significant decrease in bone turnover and 24-hour urine hydroxyproline and serum alkaline phosphatase values was observed in all patients. In contrast, the calcium, phosphorus and magnesium balances did not change significantly. In agreement with this, the partial body calcium, measured by in vivo neutron activation analysis, did not change. Intestinal calcium absorption increased initially, but returned to baseline levels 9 to 19 months after the study began. During the initial period there was a small, significant, but transient decrease in tubular reabsorption of phosphorus; this was accompanied by a significant decrease in serum phosphorus values--probably a direct effect of calcitonin rather than evidence of secondary hyperparathyroidism. Administration of salmon calcitonin to patients with Paget's disease decreases bone turnover without affecting calcium and phosphorus balances.

Aged↗
PubMed1977

Differences in the virulence of Plasmodium knowlesi for Macaca irus (fascicularis) of Philippine and Malayan origins.

This report summarizes the results of a comparative study of the virulence of the "S-M," H, and C strains of P. knowlesi for Indian rhesus monkeys (Macaca mulatta) and cynomolgus monkeys [M. irus (fascicularis)] of Malayan (West Malaysia) and Philippine origins. Each of the above strains produced fulminating, uniformly fatal infections in the rhesus monkey and mild, chronic infections, characterized by relatively low level parasitemias in cynomolgus monkeys of Philippine origin. In striking contrast, the H and C strains produced infections in cynomolgus monkeys of Malayan origin which were indistinguishable in severity from infections produced in M. mulatta. The circumstances of the study precluded evaluation of the virulence of the "S-M" strain for M. irus of Malayan origin. Even so, the available data make it necessary to qualify the long-held belief that infections with P. knowlesi in M. irus invariably follow a benign course.

Animals↗
PubMed1977

Quantitative aspects of pyrimethamine-sulfonamide synergism.

The experiments described in this report have dealt with the dimensions of therapeutic potentiation achieved when combinations of pyrimethamine and sulfadiazine were administered to rhesus monkeys infected with a drug-susceptible strain of Plasmodium cynomolgi or its pyrimethamine-resistant variant and to owl monkeys infected with strains of P. falciparum and P. vivax of varying degrees of resistance to this pyrimidine. These evaluations showed: 1) that when delivered in combination, the activities of both pyrimethamine and sulfadiazine against infections with any of the above strains were enhanced significantly; 2) that in infections with the Ro and Ro/PM strains of P. cynomolgi and the Vietnam Palo Alto strain of P. vivax, concomitant delivery of the two agents resulted in a 32-fold increase in the activity of pyrimethamine and a 50- to 100-fold increase in the activity of sulfadizine; 3) that as a result of this synergism, infections with the pyrimethamine resistant Ro/PM and Palo Alto strains could be cured with a fraction of the maximum tolerated dose of this drug; 4) that in marked contrast to the above result, infections with the Malayan Camp and Vietnam Smith strains of P. falciparum could not be cured regularly by combination regimens which included the maximally tolerated dose of pyrimethamine. This poor response has been attributed to the high levels of pyrimethamine-resistance possessed by these strains. It is believed that the comparatively small but not insignificant incidences of treatment failures associated with delivery of pyrimethamine-sulfonamide combinations to both patients and human volunteers infected with multidrug-resistant strains of P. falciparum rest on a similar basis.

Animals↗
PubMed1976

Prothrombin complex concentrate (Konyne) in the treatment of hemophilic patients with factor VIII inhibitors.

Two prothrombin complex concentrates, Auto-Factor IX and Proplex, have been reported to be effective in controlling bleeding in hemophilic patients with factor VIII inhibitors. A third PCC, Konyne, was used to treat 64 bleeding episodes (130 infusions) in five hemophilic patients with factor VIII inhibitors. Prompt control of bleeding was observed in each instance with doses of 15 to 100 units of factor IX/kg; no complications were encountered. Konyne resulted in in vivo and in vitro shortening of the partial thromboplastin time of patients with factor VIII inhibitors, but the mechanism of action is unknown. If further studies confirm the efficacy and safety of PCC in the treatment of such patients, its use for this purpose could lead to significant saving of factor VIII concentrates.

Adolescent↗