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Biomedical subjects

C H Miller

Publications and source records attributed to C H Miller.

At least 199 records · Page 11Linked to original sources
PubMed1979

Genetics of classic von Willebrand's disease. II. Optimal assignment of the heterozygous genotype (diagnosis) by discriminant analysis.

In classic von Willebrand's disease (vWd), assignment of the heterozygous genotype for genetic studies and diagnosis for clinical purposes (which are not exactly the same) are formidable problems. We have pointed out in the first report in this series that almost 50% of the members of two large kindred who transmitted this disease, and were therefore heterozygous, were scored as normal by the usual tests of hemostasis. This report describes how this large proportion can be significantly reduced by application of discriminant analysis. Using linear discriminants in three variables--coagulation factor VIII (VIII:C), factor-VII-related antigen (VIIIR:Ag), and the ristocetin cofactor related to factor VIII (VIIIR:WF)--we were able to classify as heterozygous more than 80% of the transmitters in the two large kindred. It was of particular interest that the four parents of two related vWd homozygotes could be scored as heterozygous by discriminant analysis even though all their laboratory tests were within the normal ranges.

Adult↗
PubMed1978

Cell-associated levan of Actinomyces viscosus.

Actinomyces viscosus ATCC 15987 was examined for the presence of cell-associated levan by absorption of myeloma proteins with antilevan activity and direct immunofluorescence. Levan was not detectable on the surface of glucose-grown A. viscosus, but after a brief incubation of these cells with 5% sucrose, they were encapsulated with tenaciously adhering levan. The levan layer constituted between 0.02 and 0.03% of the cell dry weight. In contrast, sucrose-grown A. viscosus cells possessed a low level of cell-associated levan, which was only moderately increased by incubation in sucrose and which partially existed as a loose slime rather than a tenacious capsule.

Actinomyces↗
PubMed1978

Factors affecting the aggregation of Actinomyces naeslundii during growth and in washed cell suspensions.

Various factors affecting the aggregation of Actinomyces naeslundii strain 12104 were studied. When the pH of glucose-supplemented growth medium fell below 5.5, the cells aggregated and formed microbial masses which tenaciously adhered to the culture vessels. When the organism was cultured in the same medium in the absence of glucose, maximum growth was reduced and the final culture pH values remained above 6.5, but the cells were more dispersed and nonadherent. Adjusting the final pH of these cultures to below 5.5 with HCl caused the cells to aggregate. Cells from unsupplemented cultures with final pH values of 6.7 were washed by centrifugation, dispersed by vigorous shaking, and suspended in buffer at pH values ranging from 4.5 to 8.0. Aggregation (expressed as the percent reduction of optical density at 520 nm after incubation at 37 degrees C) occurred rapidly at pH values below 6.0 but did not readily occur at higher pH values. Aggregation of strain 12104 in washed cell suspensions was induced by low pH and influenced by cell concentration and ionic strength of the environment. Low pH values also induced aggregation in washed cell suspensions of Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, and Actinomyces viscosus.

Actinomyces↗
PubMed1978

Degradation of levan by Actinomyces viscosus.

Actinomyces viscosus ATCC 15987 was examined for its ability to hydrolyze its own levan. Washed whole cells and an ammonium sulfate fraction from cell-free culture fluids were shown to possess levan hydrolase activity. Analyses of reaction mixtures by gel filtration and thin-layer chromatography demonstrated that the product of levan hydrolysis was free fructose. The cell-associated and extracellular enzyme preparations also hydrolyzed inulin and the levans synthesized by Aerobacter levanicum and Bacillus subtilis. Growth of A. viscosus in media supplemented with 0.1% A. viscosus levan resulted in a 33-fold increase and a 7-fold increase in the specific activities of the respective extracellular and cell-associated enzymes when compared with those from 55 mM glucose cultures. Growth in the presence of 29.2 mM sucrose resulted in a 28-fold increase and a 5-fold increase in the specific activities of the respective enzymes when compared with those from the glucose cultures. The extracellular enzyme exhibited high activity over a wide pH range, with 87 and 89% of its pH 6.0 optimum activity at pH 5.0 and 7.0, respectively. The cell-associated enzyme also exhibited optimum activity at pH 6.0, but this was decreased to 10 and 20% at pH 5.0 and 7.0, respectively. Analysis for the presence of extracellular levan during growth of A. viscosus in sucrose broths demonstrated that peak levan concentrations occurred during the mid-exponential to late-exponential phase of growth followed by a rapid decline in extracellular levan as a result of levan hydrolase activity.

Actinomyces↗
PubMed1978

Cell surface markers on canine lymphocytes.

Reference values for T and B lymphocytes were determined on lymphocytes from canine thymus, spleen, lymph node, bone marrow, and peripheral blood by use of erythrocyte (E) and erythrocyte-antibody-complement (EAC) rosette assays, plus a direct fluorescent technique for assay of surface immunoglobulins. Numbers of T lymphocytes, indicated by E rosette formation with human erythrocytes, ranged from a low of 1% in the thymus to 13% in the peripheral blood, whereas B-lymphocyte numbers ranged from 3% (thymus) to 41% (bone marrow) and from 6% (thymus) to 36% (bone marrow), as indicated by EAC rosette formation or presence of surface immunoglobulins respectively. Stimulation of peripheral blood lymphocytes with either phytohemagglutinin or concanavalin A increased the total number of E-rosetting cells two to threefold, whereas the number of EAC-rosetting cells decreased by half. Further, the percentage of cells bearing Fc receptors increased after phytohemagglutinin stimulation. These results indicate the E rosette technique can be used to identify and to monitor a population of canine T lymphocytes.

Animals↗
PubMed1978

Prenatal diagnosis by linkage: hemophilia A and polymorphic glucose-6-phosphate deydrogenase.

Close linkage between the loci for G6PD and hemophilia A allows prenatal diagnosis of hemophilia in the fetuses of certain women who are heterozygous for two electrophoretic types of G6PD. A pregnant woman, whose mother was an obligate heterozygote for hemophilia, had factor VIII levels and a G6PD phenotype that failed to indicate clearly whether or not she was heterozygous for hemophilia. The G6PD phenotype of her male fetus revealed that the fetus was unlikely to have hemophilia.

Female↗
PubMed1977

Extracellular dextran hydrolase from Streptococcus mutans strain 6715.

Streptococcus mutans strain 6715 was shown to produce an extracellular dextramase with endohydrolytic alpha-(1 leads to 6)-glucan-6-glucanohydrolase activity. The enzyme degraded soluble polymers produced by some oral streptococci but did not disperse the streptococcal plaques tested. Enzyme levels in the culture supernatant were elevated in sucrose and sucrose plus glucose cultures but remained at basal levels in glucose and dextran plus glucose cultures.

Chromatography, Gel↗
PubMed1977

Opiate tolerance: independence from immunological mechanisms.

The possibility that immunological mechanisms are involved in the development of tolerance to the analgesic effect of morphine was investigated, focusing on several immunological parameters. The data indicate that transfer of spleen cells and bone marrow cells obtained from morphine-tolerant donors into nontolerant syngeneic recipient mice did not result in the transfer of tolerance to the analgesic activity of morphine. Furthermore, the data indicate that the thymus, which is essential for the immunological response to many antigens, was not involved in the induction of tolerance to the opiate since tolerance was induced in thymectomized mice as well as in genetically athymic mice. The results suggest that immunological factors do not seem to play a crucial role in the phenomenon of tolerance to the analgesic activity of morphine.

Analgesics↗
PubMed1976

Retrograde venous cardiac perfusion for myocardial revascularization: an experimental evaluation.

This study evaluates cardiac function in dogs during retrograde perfusion through the coronary sinus. Five hearts perfused retrograde in an ex vivo apparatus demonstrated rapid and marked increases in weight and perfusion pressure, became hemorrhagic, and contracted poorly within one hour. Five similarly perfused hearts treated with phenoxybenzamine experienced no increase in weight or perfusion pressure and maintained good color and contractions for up to one hour. Five additional hearts treated with phenoxybenzamine did not develop hemorrhage, edema, increased weight, or increased perfusion pressure but could maintain the systemic circulation for only brief periods after 15 minutes of intermittent cardiopulmonary bypass support. We conclude that cardiac viability can be maintained with retrograde perfusion enhanced with alpha blocking agents. However, hearts so perfused cannot maintain adequate systemic pressure. The data suggests that extensive myocardial revascularization through the retrograde venous route would be ineffective.

Animals↗
PubMed1976

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Dentistry, Operative↗
PubMed1976

The phenotypic range of hemophilia A carriers.

We have described the study of a small kindred with X-linked hemophilia A. It was ascertained through a clinically affected female, the daughter of a man with moderately severe hemophilia. The pedigree and the proband's phenotype suggest that she may be a heterozygote in whom most of the normal alleles at the VIII-1 locus are not active. She has two sisters, also obligatory carriers. The three sisters exhibit the three phenotypes possible for heterozygous females: clinically affected, clinically normal but phenotypically abnormal as determined by laboratory tests, and clinically and phenotypically normal.

Adult↗