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Biomedical subjects

R W Miller

Publications and source records attributed to R W Miller.

At least 181 records · Page 10Linked to original sources

Familial non-Hodgkin lymphoma: histologic diversity and relation to other cancers.

Familial non-Hodgkin lymphoma (NHL) cases were classified according to the histologic criteria (modified) of Rappaport, to determine the extent of morphologic similarities of the tumors. In four families affected members had different tumor histologies that may be observed in an individual patient as the lymphoma progresses. In two families, the affected relatives had tumors of seemingly discordant histology. These tumors may nonetheless be etiologically related as indicated by the pattern of laboratory abnormalities, especially immunologic, in affected as well as unaffected members. The 20 cases had a reversal of the sex ratio (M/F) usually seen in NHL: 0.5 instead of 1.3. Other tumors observed in these families included primary hepatocellular carcinoma, pulmonary adenocarcinoma, Hodgkin disease, and acute lymphocytic leukemia - all of which have been associated with inborn or acquired immunodeficiency states.

Carcinoma↗

Neurofibromatosis and childhood leukemia.

Twelve new cases of childhood leukemia and neurofibromatosis were ascertained and evaluated in conjunction with 17 previously well-documented cases. The ratio of ALL:nonlymphocytic leukemia was 9:20, markedly different from the 4:1 ratio in children without NF. Rarer subtypes predominated: 8 CML and 8 AMML. The peculiar distribution of leukemia by cell type and the number of cases observed in the United States indicate that the risk of childhood leukemia in NF is increased. Two possible variants were noted: NF with "transient leukemia," and multiple skin xanthomas with nonlymphocytic leukemia.

Adolescent↗

Osmotically induced removal of water from fungal cells as determined by a spin probe technique.

Effects of physical environment on plasma membrane semipermeability and osmotic induction of changes in aqueous cytoplasmic volume were studied in vegetative and spore cells of a plant pathogenic fungus, Fusarium sulphureum. A direct method, employing a spin probe molecule that partitioned between intracellular aqueous and hydrophobic phases, allowed measurement of reversible water movement out of macroconidial cells and chlamydospores exposed to solutions of high osmolarity. Equilibrium distribution of the spin probe between intracellular aqueous and lipid phases was more rapid than movement of water in and out of the cells. The extent of water removal was exponentially dependent on osmotic strength. Some cells became irreversibly permeable to divalent cations on treatment with sodium chloride above 1.5 osmolar but addition of sucrose to the suspension medium at equivalent osmolar concentrations caused water removal without adversely affecting the viability. Sucrose also protected the plasma membrane against damage during freeze-drying. Induction of plasma membrane damage by osmotic shock or freeze-drying permitted rapid permeation of nickel ions. Neither slow equilibration of intracellular components with divalent paramagnetic cations nor partial permeability of damaged plasma membranes to these ions was observed.

Journal Article↗

Growth temperature-dependent stearoyl coenzyme A desaturase activity of Fusarium oxysporum microsomes.

The characteristics of the microsomal stearoyl CoA desaturase (EC 1.14.99.5) of vegetative Fusarium oxysporum cells grown at different temperatures were studied. The enzyme had an unusual preference for NADPH (Km = 38 micrometers) over NADH (Km = 89 micrometers) as electron donor, and a relatively high optimum pH of 8.3. Enzyme activity was highest in microsomes from cells grown at 37 degrees C and lowest in cells grown at 15 degrees C. This result correlated well with the observed changes in oleic acid content of the microsomal lipids. Both NADPH-linked reductase activities and hemoprotein content were lowest in cells grown at 37 degrees C. Spectrophotometric analysis of the microsomal hemoproteins indicated the absence of cytochrome b5 and the presence of a b-type heme with a pyridine hemochrome alpha band absorption maximum at 565 nm. Labile sulfide analysis and inhibitor studies with thenoyltrifluoroacetone suggested a role for an iron-sulfur protein in the electron transfer system associated with the desaturase.

Electron Transport↗

Army technologists: 29-year follow up for cause of death.

A previous 18-year follow-up study revealed no significant excess of cancer among men who served in the Army during World War II as radiological technologists (n = 6,560) as compared with men who served as medical, laboratory, or pharmacy technologists (n = 6,826). Extension of the follow up by 11 years (1946-1974) revealed that 145 former radiological technologists had died of cancer, as compared with 158 controls. No statistically significant differences were found between these groups for individual sites of cancer or for deaths from other causes.

Follow-Up Studies↗

Environmental causes of cancer in childhood.

Although it is commonly said that only a small proportion of childhood cancers are caused by environmental exposures, much has been learned about exogenous carcinogens through study of their effects or noneffects in children: 1. Ionizing radiation poses some risk no matter how small the dose. 2. Concepts about the viral etiology of cancer have had to be adapted to fit observations in children concerning candidate viruses. 3. Transplacental chemical carcinogenesis has become a reality and poses an increasing threat as chemical pollution worsens. 4. Questions have been raised about the risk of breast feeding in (at present) rare instances when the mother has been heavily exposed to chemicals that are excreted in the fat of breast milk. 5. A few drugs administered to children induce cancers within the pediatric age-span. The pediatrician must take action not only against exogenous agents that induce cancer while the patient is under his care, but also against exposures that begin in utero and lie latent or accumulate throughout life to give rise to cancers in the years or decades ahead. There is much more to carcinogenesis than the effects of the environment. Important information has been gained about the origins of cancer and about human biology in general through studies of children who are unusually susceptible to certain forms of neoplasia. Knowing the mechanisms involved may lead to new modes of treatment, to screening tests for environmental carcinogens or to methods for detecting cancer early enough for treatment to be life-saving.

Adolescent↗

Residue content of beef feedlot manure after feeding diethylstilbestrol, chlortetracycline and Ronnel and the use of stirofos to reduce population of fly larvae in feedlot manure.

Two beef cattle feedlot experiments were conducted to determine the amount of certain agricultural chemicals that are likely to be found in both fresh and stored feedlot manure and to investigate fly control in this manure. In experiment 1, diethylstilbestrol (DES), chlortetracycline (CTC), and ronnel were used as feed additives. Fresh manure, stored manure, runoff water, manure weathered on pasture, and soil from pasture fertilized with manure were analyzed for these additives. Stirofos was added to fresh manure as a larvicide for fly control. In experiment 2, the residue aspects of DES and CTC were repeated. In this experiment, stirofos instead of ronnel was fed with DES and CTC. Sixty-eight percent of the DES fed to cattle appeared in fresh manure and 52% in manure stored for 12 weeks. Comparable percentage values were 17 and 11% for CTC and 13 and 3% for ronnel; somewhat less DES and CTC were found when a concentrate diet was fed. Detectable amounts of DES, ACT, and ronnel were not found in runoff water, weathered manure, or soil. Adding an emulsifiable concentrate formulation of stirofos directly to manure at a rate of approximately 45 ppm of wet manure completely controlled the larvae of house fly (Musca domestica L.) whereas feeding stirofos at a rate of 1.5 mg per kg of body weight daily reduced larval counts 82% in manure from forage-fed heifers and 63% in manure from concentrate-fed heifers. Stirofos was not detected in runoff water, weathered waste, or soil.

Animal Feed↗

Childhood cancer: etiologic clues from epidemiology.

Epidemiologic reseach has revealed a wide spectrum of etiologic information concerning childhood cancer. Often, important clues have come from observations made by alert practitioners. The school health professional can help further progress in cancer research by observing peculiarities of environmental exposures as well as the family's medical history when cancer affects a child. Any unusual findings should be referred to an appropriate research center for evaluation.

Adolescent↗

The effect of ionic surface-active agents on macroconidial plasma membrane of Fusarium sulphureum.

A method was developed for direct assessment of changes in cytoplasmic volume and permeability of plasma membranes of intact cells to divalent cations. This technique, which ultilized an amphipathic spin label partitioning between intracellular aqueous and hydrophobic environments, allowed estimates of the proportion of cells in a homogenous population sustaining membrane damage associated with Ni+2 and water permeability and the rate at which such damage was induced. Several specific effects of cationic and anionic surfactants on the macroconidial plasma membranes of Fusarium sulphureum Schlect (isolate 1) were distinguished on the basis of detergent concentration and charge. The induction of water uptake by the cells was found to be an effect of dodecylguanidine acetate (Dodine), a cationic fungicide, at low concentration. At higher concentrations (greater than 5 X 10(-5) M) both the impermeability of the plasma membrane to divalent cations and the ability to accumulate actively L-phenylalanine were lost irreversibly and cell lysis occurred above 5 X 10(-4) M. Sodium dodecyl sulfate eliminated divalent cation impermeability more rapidly than Dodine but was less effective in inhibiting active transport function. An antagonistic effect between cationic and anionic detergents was observed.

Biological Transport, Active↗