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Biomedical subjects

G C Miller

Publications and source records attributed to G C Miller.

At least 19 recordsLinked to original sources
PubMed1992

Photoactivation of hypericin generates singlet oxygen in mitochondria and inhibits succinoxidase.

Photosensitized inhibition of mitochondrial succinoxidase by hypericin was measured in vitro and found to be drug-dose, light-dose, and wavelength dependent. Singlet oxygen generation, monitored using the singlet oxygen trap tetramethylethylene, and oxygen consumption in isolated mitochondria sensitized by hypericin were also light-dose and wavelength dependent. Unequivocal evidence for the generation of singlet oxygen was obtained using kinetic isotope ratios of products from the reaction between singlet oxygen and geminally deuterated tetramethylethylene. An action spectrum for the inhibition of succinoxidase was measured at wavelengths between 400 and 700 nm and found to parallel the recorded visible absorption spectrum of hypericin in isolated mitochondria. The greatest singlet oxygen generation, oxygen consumption, and succinoxidase inhibition occurred with white light or 600 nm irradiation. These data are consistent with a type II singlet-oxygen-mediated mechanism for hypericin induced photosensitized inhibition of mitochondrial succinoxidase.

Animals↗
PubMed1990

Epidemic oral ulceration in largemouth bass (Micropterus salmoides) associated with the leech Myzobdella lugubris.

An epidemic of severe ulcerations of the tongue and buccal cavity was documented in subadult and adult largemouth bass (Micropterus salmoides) from Currituck Sound, North Carolina (USA). Other external clinical signs were not present. Between November 1986 and May 1987, reports from fishermen indicated that as many as 90% of large (greater than 300 mm total length) bass were affected. Older fish were the most commonly involved. The leech, Myzobdella lugubris (= Illinobdella moorei), was consistently present on or near the lesions. Lesions were heavily infected with several different bacteria that were apparently secondary invaders. Stressful (high) salinity or an interruption in the normal migratory cycle of the parasite are suggested as possible causes for this condition in these bass.

Animals↗
PubMed1989

Isolation, characterization and determination of trace organic impurities in FD&C red no. 40.

The unsulfonated aromatic amine 4-nitro-p-cresidine (2-methoxy-5-methyl-4-nitrobenzenamine) was identified as an impurity in the regulated color additive FD&C Red. No. 40. The compound was isolated from the water-soluble color by extraction with chloroform, followed by transfer of the free amines to acid solution and subsequent separation by reversed-phase high-performance liquid chromatography. The 4-nitro-p-cresidine was collected and then identified by gas chromatography-mass spectrometry. The levels of 4-nitro-p-cresidine as well as p-cresidine and aniline were determined in commercial batches of FD&C Red. No. 40.

Aniline Compounds↗
PubMed1986

Microcephaly, short stature, and developmental delay associated with a chemotactic defect and transient hypogammaglobulinaemia in two brothers.

Two brothers presented with unusual facial features, microcephaly, developmental delay, and severe postnatal growth retardation. They both developed eczema in infancy and have had recurrent infections. Additional physical findings in both boys included hypogonadism, flexion contractures, hypoplastic patellae, and scoliosis. Their facial similarity was striking with sloping foreheads, beaked noses, large, protruding ears, and micrognathia. Low levels of serum gammaglobulins and defective chemotaxis were present in both boys in infancy. The hypogammaglobulinaemia was transient and improved, reaching normal levels by 3 1/2 years and 15 months, respectively. Defective chemotaxis and recurrent infections have persisted to the present. Both parents were normal. The mode of inheritance was not clear, as both X linked and autosomal recessive patterns were possible. Although patients with congenital malformations who also had immunodeficiency have previously been reported, immune system abnormalities, especially those of a transient nature, may frequently go unrecognised.

Abnormalities, Multiple↗
PubMed1985

Factory fixation of an arc curve into brachial coronary artery catheters of the manipulative type: a new curve for Sones' type catheters.

Advantage was found in factory fixing an approximation of the curve that has long been hand-formed at the tableside by angiographers using the manipulative type brachial-coronary technique. It consists of a 7 cm arc of a circle of 10 cm diameter. Used in 68 different patients, it was found to definitely facilitate and speed selective cannulation of the coronary artery ostia as compared to previous curves.

Adult↗
PubMed1985

Enkephalins: immunomodulators.

Our original studies of the enkephalins were centered on behavioral stress and brain dopaminergic interactions. More recently we discovered the enkephalins to be immunomodulators as evidenced by their enhancement effects on lymphocyte blastogenesis in mice, increases in the sizes of the thymus or spleen in rodents, and prolongation of survival of BDF1 mice inoculated with attentuated L1210 cells. Finally, in studies of human blood samples from both normal volunteers and cancer patients, the enkephalins were demonstrated to stimulate active T cell rosettes and natural killer cell activities (in vitro). These studies support our hypothesis that, in stress, the enkephalins modulate the effects of steroid hormones on the immune system.

Acoustic Stimulation↗
PubMed1984

Enkephalins--enhancement of active T-cell rosettes from normal volunteers.

Both methionine enkephalin and leucine enkephalin were found to increase significantly the active T-cell rosettes of normal volunteers. Neither enkephalin altered total T-cell rosettes. It is proposed that the endogenous enkephalins (methionine as well as leucine) have a role in cell-mediated immunity and T-cell function.

Adjuvants, Immunologic↗
PubMed1984

A histochemical and immunohistological study of a testicular malignant teratoma containing embryonic and extraembryonic elements in various stages of development.

A testicular malignant teratoma containing embryoid bodies and other embryonic and extra-embryonic structures in various stages of development has been examined by several histochemical and immunohistological techniques to study the distribution of various substances in the teratomatous elements. The substances demonstrated included various types of mucins; argyrophil, argentaffin, Paneth cells and haemosiderin granules; alpha-fetoprotein, alpha-l-anti-trypsin, lysozyme, beta-HCG and CEA. The significance of the findings is discussed in relation to early embryonic development.

Adult↗
PubMed1983

Enkephalins--enhancement of active T-cell rosettes from lymphoma patients.

Methionine enkephalin was found to increase significantly the active T-cell rosettes from lymphoma patients. In sharp contrast, the leucine enkephalin was observed to increase active rosettes only at a single low concentration. Neither enkephalin significantly altered the total T-cell rosettes. It is suggested that methionine enkephalin could have a significant influence in enhancing cell-mediated immunity and T-cell function, particularly in lymphoma patients.

Enkephalins↗
PubMed1983

Enkephalins as immunomodulators.

The protective effects of methionine enkephalin as well as leucine enkephalin were studied in BDF1 mice inoculated with 1 X 10(4) and 1 X 10(2) cells of L1210 murine leukemia. Significant increases in number of survivors were observed in mice treated with enkephalins. Methionine enkephalin in the presence of PHA was found to stimulate lymphocyte blastogenesis at concentrations of 1 mg/ml to 10(-8) mg/ml. In the case of leucine enkephalin, concentrations of 1 mg/ml to 10(-10) mg/ml stimulated blastogenesis. Stimulation of blastogenesis was seen at PHA dilutions of 1:100, 1:250, 1:750, with both methionine enkephalin and leucine enkephalin. The results are discussed in terms of immunomodulation. It is proposed that endogenous enkephalins play a neuroendocrine role between the central nervous system and the immune system and are direct immunostimulants.

Animals↗
PubMed1982

Pesticide photoproducts: generation and significance.

As with the parent pesticide, the significance of a pesticide photoproduct depends on its concentration in a given environmental compartment, its toxicity, and exposure of the organism or ecosystem of interest. This requires an understanding of the production and environmental chemistry of each photoproduct as well as its toxicity. While these data are generally available for the parent pesticide, they are rarely determined in detail for the photoproducts. Although the environmental photochemistry of each pesticide is different, some generalizations can be made. Photochemical oxidations, reductions, hydrolytic reactions, and isomerizations often generate products identical to those of metabolic and nonbiological transformations. The chemistry and environmental stability of each individual photoproduct can be substantially different from those of the original pesticide and other products. With several notable exceptions, however, photoproducts are generally less stable to environmental forces and less toxic than the parent pesticide, at least to the target organism. A most significant exception is the P = S to P = O conversion in the organophosphorus insecticides. This sunlight promoted reaction is important in treated fields and has been implicated as a cause of injury to farmworkers.

Air Pollutants↗