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Biomedical subjects

G Chase

Publications and source records attributed to G Chase.

6 recordsLinked to original sources

Prophylactic transfusions of normal red blood cells during pregnancies complicated by sickle cell hemoglobinopathies.

Prophylactic transfusions of normal donor red cells were administered during 37 pregnancies to women with sickle cell anemia, sickle cell-hemoglobin C disease, or sickle cell-beta thalassemia disease. Once the diagnosis was confirmed, the transfusions were administered intermittently throughout the rest of the pregnancy in such amounts and at such frequencies that no more than 60% of the circulating red cells contained hemoglobin S and the hematocrit was above 25. The maternal mortality rate was zero and maternal morbidity as the consequence of the sickle cell hemoglobinopathy was minimal. The perinatal mortality rate was appreciably reduced when compared to that previously observed without prophylactic transfusions but perinatal morbidity was still excessive. Evidence that the intrauterine environment was compromised, in spite of the transfusions consisted of an increased frequency of growth-retarded fetuses, of meconium staining of amnionic fluid, and of ominous decelerations of fetal heart rate. Morbidity from the transfusions was troublesome. Nonetheless, it is concluded tentatively that both the mother with a sickle cell hemoglobinopathy and her fetus are likely to benefit from prophylactic transfusions of normal donor red cells administered during one pregnancy according to the protocol employed in this study.

Anemia, Sickle Cell

Drug utilization review in an HMO. I. Introduction and examples of methodology.

An experimental drug utilization review program was developed for a health maintenance organization (HMO). The objectives of the program were to develop and implement an ongoing mechanism for reviewing drug use using criteria based on the scientific literature, and to evaluate the effect of the drug use review program on physician precribing patterns. Seven therapeutic categories of drugs, accounting for over 65 per cent of prescribing, were selected and criteria developed for their use. The drug use review prcedure is described briefly. The evaluation of the drug use review program is based on a comparison of rates of prescription use for specific therapeutic categories before and after the criteria were ceveloped and approved. As an example, data for the antihistamine therapeutic category are presented. Criteria for prescribing antihistamines suggested restricting use of combination cold preparations and refraiming from antihistamine use in viral upper respiratory tract infections. After the criteria were adopted, prescribing of antihistamines for viral URIs declined, particularly in pediatrics. In general, prescribing of combination antihistamine preparations did not change; where one combination preparation was deleted from the formulary, prescribers appeared to substitute another combination preparation.

Adolescent

Reproductive performance of male and female phenotypes in three sex chromosomal genotypes(XX, XY, YY) in the killifish, Oryzias latipes.

The present study investigates the juvenile and adult reproductive performance of Japanese killifish, Oryzias latipes, which were successfully sex-reversed by feeding them male or female sex hormones during the fry stage. Sexual maturation of these laboratory grown fish of three known genotypes (XX, SY, YY) occurred earliest in untreated genotypes, next in genotypes treated with male hormone (methyl testosterone) and female hormone (estrone), respectively. The delay in sexual maturation caused by early exogenous, sex-hormone treatment may represent a disturbance in the delicate neural-gonadal axis. However, the degree of response was also strongly influenced by the animal's sex chromosomal genotype. XX fish, normally phenotypic females, were affected more by the male hormone than by the female hormone. XY and YY fish, normally phenotypic males, were delayed more by the female hormone than by the male hormone. This specific sex hormone-sex genotype interaction also influenced adult reproductive performance (sperm or egg production). Differences in the metabolism of male and female sex hormones by the XX, XY, and YY fish are probably responsible for these interesting findings.

Age Factors

A computer-oriented linkage analysis scheme.

A comprehensive, computer-oriented scheme for genetic linkage analysis is described. It computes the likelihood of a complex pedigree allowing for many non-standard features including multiple alleles (up to four per locus), multiple mates, more than one mating in the eldest generation, consanguinity, missing or partially tested persons, and different recombination fractions between males and females. The program works by computing weighted likelihoods in a vertical, descending fashion. First, the set of possible genotypes for the members of the eldest generation is determined and prior probabilities assigned to these states of nature (based on gene frequency calculations). Phenotypic information is used to modify these probabilities in the standard manner. Then, for a particular set of genotypes, the conditional likelihood of the remainder of the pedigree is computed. This calculation may itself be many-branched and therefore a computer is necessary to keep track of the stages of the process. When the youngest generation has been taken into account, a final likelihood is determined, reflecting all information in the pedigree. The current version of the program successfully calculates the exact likelihood of a complex pedigree which was designed to exploit the non-standard features of the program. It has also computed likelihoods for a published pedigree, and the results are essentially equal to those obtained by the other authors using a previously available computer scheme for linkage analysis.

Diagnosis, Computer-Assisted

A longitudinal study of total body potassium in normal children.

Most investigators studying changes in body composition during growth agree to the desirability of having longitudinal data. A group of 110 boys and 126 girls, studied annually for 4-5 years with 880 measurements of total body K in a 2pi liquid scintillation whole body counter, had total body K vs. height and total body K vs. weight data that fit previously described regression lines.

Adolescent

Cyclophosphamide protection in NZB/NZW disease. Mechanisms and therapeutic regimens.

Regular administration of cyclophosphamide to NZB/NZW female mice effectively protects against the nephritis that is thought to be a model for human SLE nephritis. Reductions in serologic, histologic, and immunogluorescent parameters of the disease are correlated. Intermittent as well as continuous administration of the drug is effective without the development of leukopenia. Possible mechanisms of drug action and a modified approach to therapy of immune complex disease are discussed.

Animals