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Biomedical subjects

R L Miller

Publications and source records attributed to R L Miller.

At least 217 records · Page 12Linked to original sources
PubMed1980

Demonstration of an endogenous circadian rhythm of alpha-melanocyte stimulating hormone in the rat pineal gland.

alpha-Melanocyte stimulating hormone (alpha-MSH) has been identified and characterized in the rat pineal gland by a combination of immunochemical and high pressure liquid chromatographic techniques. The immunoreactivity in pineal extracts was separated into two chromatographic components. The major component had a retention time identical to that of alpha-MSH while the minor component eluted just slightly before standard alpha-MSH. Male rats maintained in a 12 h photoperiod demonstrated a marked circadian rhythm in pineal alpha-MSH concentration. Concentrations that peaked at 07.00 h, 1 h after the lights were turned on, were greater than 5 times the nadir which occurred at 01.000 h. Animals house in chronic dark for 7 days maintained the diurnal variation of alpha-MSH concentrations. However, in chronically dark housed rats, the peak shifted to 05.000 h and was greater than 10 times the nidir of this rhythm and approximately 4 time the peak at 07.00 in alternating light/dark conditions. Rats exposed to chronic light for 7 days maintained a pineal alpha-MSH rhythm although the amplitude of the peak was significantly decreased compared to the rhythm in animals housed in alternating light/dark conditions. Neither hypophysectomy nor superior cervical ganglionectomy had any effect on the alpha-MSH rhythm. Lesion of the arcuate nucleus, the major source of alpha-MSH-containing nerves in the brain, did not significantly affect pineal alpha-MSH concentrations. These data demonstrate a circadian alpha-MSH rhythm in the rat pineal and suggest an alpha-MSH involvement in the rhythmic processes of the pineal gland.

Animals↗
PubMed1980

Brain cancer in petrochemical workers: a case series report.

Eighteen primary brain cancer deaths among male workers at one Texas petrochemical plant from 1965-1980 are reported. Federal officials from OSHA and NIOSH are performing with company cooperation an historical prospective cohort mortality study, a case-control study, and neuropathological case confirmation. Average age at death was 53 (range 30-66). Median employment was 21 years and median latency was 24 years. 15/18 tumors were glioblastoma multiforme, an unusual histologic distribution. A preliminary estimate reveals a plant-wide excess brain cancer risk twice expected among 6,800 white males at the plant since 1941. Brain cancer mortality rates in surrounding counties are in the median range for US counties from 1950-1969. Ten recognized or suspected carcinogens are present in quantities greater than 10(6) lbs/yr. To date no common chemical exposures or work assignments have been identified among the cases. Data on 26 experimental brain carcinogens and relevant epidemiological studies are provided.

Adult↗
PubMed1980

Polyethylene glycol gradient solubilization of lysyl hydroxylase.

Polyethylene glycol (PEG) was substituted for ammonium sulfate in the gradient solubilization chromatographic procedure for the purification of proteins. Preliminary studies utilizing this method for fractionation of a crude lysyl hydroxylase preparation yielded an increase both in purity and in recovery of activity when compared with fractional precipitation with PEG. Turbidity, evident in resuspended fractional precipitates, was not found in PEG gradient solubilization fractions containing enzymatic activity.

Animals↗
PubMed1980

Histiocytosis X: a clinical presentation.

A 56-year-old male complained of chronic oral ulcers. Initial workup revealed diffuse alveolar bone destruction and other systemic disturbances including diabetes insipidus. Biopsy suggested histiocytosis X and further tests verified the diagnosis. A clinical differential diagnosis is developed, follow-up is presented and the entities comprising histiocytosis X are discussed.

Carcinoma, Squamous Cell↗
PubMed1980

Histochemical reactivity of peanut lectin-horseradish peroxidase conjugate.

A peanut lectin-horseradish peroxidase (PL-HRP) conjugate has been applied to histochemical staining of paraffin sections of various mouse organs. The PL-HRP conjugate has selectively reacted with secretory bodies, the Golgi zone, and the apical cell surface in various cell types. Some positive sites, including lingual and tracheal serous glands, Brunner's glands, and the brush border of the proximal straight nephron, contained periodic acid-Schiff (PAS)-positive glycoconjugate with no affinity for basic reagents. The stored secretion in these sites was interpreted as containing neutral glycoprotein with terminal galactose residues which could, in part at least, account for the PAS reactivity. Duodenal goblet cells, which exhibited basophilia attributable to sulfate esters, also bound PL-HRP. As the binding was affected by prior sialidase digestion, the secretory glycoprotein in the duodenal goblet cells was judged to contain oligosaccharides with sulfate esters and terminal galactose uncapped by sialic acid. All sites known from their basophilia to form sialomucin failed to stain with the PL-HRP conjugate, but consistently gained reactivity following sialidase digestion and were inferred, therefore, to possess glycoproteins with oligosaccharide side chains containing subterminal galactose and terminal sialic acid. Lingual mucous glands, known to secrete a mucosubstance with basophilic properties indicative of the presence of sulfate esters but not sialic acid, stained with PL-HRP only after sialidase digestion and, accordingly, were reinterpreted as containing both sulfate esters and terminal galactose-sialic acid dimers. Staining of gastric surface epithelium demonstrated a srongly PAS-reactive neutral glycoprotein, and that of goblet cells in the cecum disclosed PAS-positive sulfated glycoprotein. The latter two sites lacked PL-HRP affinity without or with prior sialidase treatment and apparently possessed neither terminal galactose residues nor galactose-sialic acid dimers. PL-HRP affinity was observed exclusively in the Golgi cisternae of some epithelial cells, thus indicating that galactose occurs transiently as a terminal residue in this site. A few histologic sites, such as pancreatic and gastric zymogen cells and renal tubules, were devoid of both PAS reactivity and basophilia indicative of the presence of complex carbohydrate but stained strongly with the PL-HRP conjugate by means which are not understood. Galactose in the PL-HRP solution blocked or reversed the PL-HRP binding in most of the structures with an affinity for the conjugate, supporting the conclusions that the reagent is specific for galactosyl residues.

Animals↗
PubMed1980

Aphthous ulcers--a review of the literature on etiology, pathogenesis, diagnosis, and treatment.

Recurrent aphthous ulcerations are seen in everyday dental practice. These lesions may easily be misdiagnosed and mistreated. A comprehensive but nondefinitive review of the literature is presented in hope that the practitioner can better diagnose, evaluate, research, and treat RAS. Although many modalities of treatment have been advocated, a truly effective therapeutic regimen to prevent RAS does not yet seem available. Additional research on the ideology, pathogenesis, and treatment of RAS is, therefore, needed.

Adjuvants, Immunologic↗
PubMed1980

Molecular sieve generation of aviator's oxygen: Performance of a prototype system under simulated flight conditions.

The molecular sieve method of generating an enriched-oxygen breathing gas is one of several candidate onboard oxygen generation (OBOG) systems under joint Army-Navy-Air Force development for application in tactical aircraft. The performance of a nominal two-man-capacity molecular sieve oxygen generation system was characterized under simulated flight conditions. Data are given on the composition of the molecular sieve-generated breathing gas (oxygen, nitrogen, carbon dioxide, and argon) as a function of inlet air pressure, altitude, breathing gas flow rate, and ambient temperature. The maximum oxygen concentration observed was 95%, with the balance argon. At low demand flow rates and certain conditions of pressure and altitude, the argon enrichment factor exceeded that of oxygen giving a maximum argon concentration of 6.6% with the balance oxygen. The structural integrity of the unit was verified by vibration and centrifuge testing. The performance of the molecular sieve unit is discussed in the context of aircraft operating envelopes using both diluter-demand and 100% delivery subsystems.

Aerospace Medicine↗
PubMed1980

Relation of breathing oxygen-argon gas mixtures to altitude decompression sickness.

A 95% oxygen-5% argon breathing mixture produced by a molecular sieve generator was shown to be similar to a 95% O2-5% N2 mixture for breathing during 1-h exposures at 7,620 m (25,000 ft) or 10,972 m (35,000 ft), as determined by the detection of proportionate numbers of intravascular bubbles in the pulmonary artery of dogs. Comparable results were obtained with 95% O2-5% He or 100% O2. The partial pressures of a 5% mixture at 7,620 and 10,972 m were 14.1 and 8.6 torr, respectively, and were apparently low enough so that the nonmetabolizable gases did not result in differences in the incidence of intravascular bubble formation or decompression sickness. Argon at the 10% level showed a nonsignificant trend to produce more bubbles. Individual susceptibility or resistance to form bubbles was observed with the different gases. Denitrogenation with either 5 or 10% mixtures of the inert gases was quite effective, as shown by a reduction in the number of intravascular bubbles detected.

Aerospace Medicine↗
PubMed1979

Purification and enzymatic properties of lysyl hydroxylase from fetal porcine skin.

Lysyl hydroxylase from fetal porcine skin is shown to bind in a highly specific manner to aminoethyl-Sepharose 4B. When coupled to ammonium sulfate fractionation and DEAE-cellulose chromatography, chromatography of lysyl hydroxylase preparations on aminoethyl-Sepharose 4B has yielded a highly purified (greater than 95%) preparation of lysyl hydroxylase. The enzyme consists of two subunits with molecular weights of 70 000 and 115 000. The overall recovery of activity was 2.5%, yielding approximately to 3.5 mg of purified enzyme from 900 g of fetal porcine skin. The enzyme is more active at 30 degrees C than at 37 degrees C and has a pH optimum near 8.0. Both catalase and bovine serum albumin are required by the enzyme for maximum activity. The sulfhydryl reagents p-(chloromercuri)-benzoate, N-ethylmaleimide, and iodoacetamide are potent inhibitors of the enzyme, whereas dithiothreitol appears to be an activator.

Animals↗
PubMed1979

Identification, characterization and stereotaxic mapping of intraneuronal alpha-melanocyte stimulating hormone-like immunoreactive peptides in discrete regions of the rat brain.

A highly specific antibody to alpha-melanocyte stimulating hormone (alpha-MSH) was used to histochemically localize and biochemically identify and quantitate alpha-MSH immunoreactivity in nerve fibers and cell bodies of the rat brain. alpha-MSH-like immunoreactivity was contained in fibers throughout the brain. The distribution of alpha-MSH was determined by immunocytochemistry as well as by radioimmunoassay combined with microdissection techniques. High concentrations of alpha-MSH were contained in the nucleus interstitialis stria terminalis, the median eminence and the medial preoptic, anterior hypothalamic, periventricular, paraventricular, arcuate, dorsomedial, and posterior hypothalamic nuclei. Moderate alpha-MSH concentrations were noted in the amygdala, septum, central gray, dorsal raphe, and the nucleus tractus solitarius. Cell bodies containing alpha-MSH were observed only in the arcuate nucleus. The alpha-MSH-like compound in brain had similar immunochemical and electrophoretic properties of standard alpha-MSH but high pressure liquid chromatographic analysis demonstrated that the alpha-MSH-like immunoreactivity was comprised of one major and two minor components. The major immunoreactive peak had an identical retention time as alpha-MSH and therefore may be chemically identical to alpha-MSH. The similar retention times and immunoreactivity of the other two compounds suggest a similarity in size and structure to alpha-MSH. These observations demonstrate that fibers containing alpha-MSH emanate from the arcuate nucleus to innervate many other regions of the rat brain.

Animals↗
PubMed1979

Trigeminal ganglion infection by thymidine kinase-negative mutants of herpes simplex virus.

The incidence of trigeminal ganglion infection after corneal inoculation of guinea pigs with thymidine kinase-negative mutants of herpes simplex virus was markedly reduced compared to infection after inoculation of thymidine kinase-positive virus. Thymidine kinase-negative herpes simplex virus replicated well in ocular tissues in which dividing or potentially dividing cells were present, but not in trigeminal ganglion infection of nondividing neurons. Thymidine kinase-positive virus, however, replicated well in ocular tissues as well as in trigeminal ganglion. These results suggest that thymidine kinase expression of herpes simplex virus may be important in infections of sensory ganglia.

Animals↗