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Biomedical subjects

J Mason

Publications and source records attributed to J Mason.

At least 307 records · Page 17Linked to original sources
PubMed1975

Sulphate transport by rat ileum. Effect of molybdate and other anions.

Kinetic constants for SO4-2- transport by upper and lower rat ileum in vitro have been determined by computer fitting of rate vs concentration data obtained using the everted sac technique. MoO-4-2- inhibition of this transport is competitive, and kinetic constants for the inhibition were similarly determined. Transport is also inhibited by the anions WO4-2-, S2O3-2- and SeO4-2-, in the order S2O3-2- greater than SeO4-2- greater than or equal to MoO4-2- greater than WO4-2-. These anions have no effect on the transport of L-valine. Low SO4-2- transport rates were observed in sacs from animals fed a high-molybdenum diet. The significance of the results with respect to the problem of molybdate toxicity in animals is discussed, and related to the known protective effect of SO4-2-.

Animals↗
PubMed1975

The status of cardiac transplantation, 1975.

Since December 1967, 263 human cardiac transplant operations have been performed throughout the world. Eighty-two of these were performed at Stanford University Medical Center, In 1974, 27 such operations were performed, 15 at Stanford Survival rates for the entire Standford series are 48% at one year and 25% at three years; survival rates at one and three years for patients surviving the first three critical months after transplantation are 77% and 42%, respectively. Recipients under the age of 55 years, with New York Heart Association Class IV cardiac disability, are selected for transplant procedures according to criteria dictated by experience over the past seven years. A routine immunsuppressive regimen for organ transplantation, incorporating prednisone, azathioprine, and antithymocyte globulin is employed early postoperatively, and prednisone and azathioprine are used for indefinite maintenance therapy. Acute cardiac graft rejection in nearly all recipients is diagnosed by clinical signs, electrocardiographic changes, and percutaneous transvenous endomyocardial biopsy. Ninety-five percent of acute rejection episodes are reversible with appropriate immunosuppressive treatment, but infectious complications are common and have accounted for 56% of all postoperative deaths. The Stanford experience in cardiac transplantation has demonstrated the potential therapeutic value of this procedure. Maximum survival now extends beyond five years. Satisfactory graft function has been documented in long-term surviving patients, the majority of whom have enjoyed a high degree of social and physical rehabilitation.

Acute Disease↗
PubMed1975

The prevalence and relationships of malaria, anemia, and malnutrition in a coastal area of El Salvador.

To study the relationships between malaria, anemia and malnutrition, 853 school-age children from a high malaria incidence area and an adjacent low incidence area were surveyed in September 1972. For the high incidence area the malaria slide positivity rate was 3.5%, spleen rate 7.6% and malaria (indirect fluorescent antibody) serology positivity 24.7%. Contrasted to this, no positive slides, only 3 palpable spleens and a 3.4% serology positivity rate were found for the low incidence area. Twenty-three percent of those studied were anemic, but the prevalence of anemia was the same in both the high and low incidence areas. However, a selected group of children with known history of recent or actual malaria was found to be more likely to have deficient hematocrit values than were children without such history. Hypochromia and microcytosis were prominent morphologic findings in children with anemia, suggesting a diagnosis of iron deficiency. Weights and heights for age were considerably below those of a U.S. reference population but similar to nationwide Salvadoran figures. In both the high and low incidence groups, 62% had arm circumference values below 90% of standard. The distribution of weight-to-height ratios was also similar for both groups. No difference in nutritional status between the two groups could be found.

Adolescent↗
PubMed1975

Natural infections of Anopheles albimanus with Plasmodium in a small malaria focus.

Entomologic surveys conducted in a small village in an area of known high malaria transmission in El Salvador yielded a high rate of infection in Anopheles albimanus collected inside houses in which cases of malaria had occurred. Of 324 specimens dissected, 12 were found to harbor sporozoites or oocysts. This is in contrast to prior reports of extremely low infection rates in collections of this species from malarious areas, and suggests that under some circumstances A. albimanus does meet the criteria of an effective malaria vector.

Anopheles↗
PubMed1975

Patterns of Plasmodium vivax recurrence in a high-incidence coastal area of El Salvador, C. A.

During field studies carried out in 1971, 1972 and 1973 in a highly malarious coastal area of El Salvador, it was possible to collect information on the patterns of Plasmodium vivax parasite occurrence in a large number of infected individuals. In most of the persons who had experienced a malaria attack during the high transmission period in June, July, August and September, renewed activity occurred 5 to 8 months later, during the low transmission season the next year. Subsequent activity in these same cases occurred after intervals of about 4 to 9 weeks in duration. On epidemiologic grounds, and on the basis of the life patterns of the El Salvador P. vivax strains demonstrated in previous studies in volunteers, this renewal of activity probably represents the occurrence of relapses rather than new infections. This pattern is similar to the "temperature zone" strains of P. vivax, where initial relapses occur after prolonged periods, followed by subsequent relapses after much shorter intervals of inactivity. This type of relapse pattern in a tropical area may enhance the survival of the parasite through a prolonged period of vector inactivity, such as the long dry season experienced in El Salvador.

Blood↗