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Biomedical subjects

R Mills

Publications and source records attributed to R Mills.

At least 73 records · Page 4Linked to original sources
PubMed1988

A microanalysis of wheel running in male and female rats.

The pattern of ad lib wheel running was studied in adult Sprague-Dawley rats. Wheel turns per 20 seconds were recorded for 5 days. Females ran more than males but both ran chiefly at night, with a peak at the beginning and a decline to low levels by daytime. Log-survivor plots showed running occurred in distinct episodes separated by long periods of nonrunning. Both the nightly decrease and the sex difference in running were due to changes in duration of episodes and the running speed. Initiation of running, as reflected in the length of nonrunning periods was similar in both sexes and remained constant over the night. Running was discussed in terms of independent initiation and termination factors and its parallels to eating patterns.

Animals↗
PubMed1987

HDL cholesterol and the acute phase reaction following myocardial infarction and acute pancreatitis.

The response of HDL in the acute phase reaction following myocardial infarction (MI) (82 subjects) and acute pancreatitis (AP) (30 subjects) has been examined and compared with that in a control group (76 subjects) admitted to hospital with suspected MI but in whom the diagnosis was not subsequently confirmed. The temporal and quantitative characteristics of the changes in concentration of the positive acute phase reactants fibrinogen and alpha 1-antitrypsin and the negative acute phase reactants albumin and LDL were similar in the myocardial infarction and acute pancreatitis subjects. In contrast, the response of HDL was different to that of the other transport proteins both within each experimental group and between the two groups. This indicated that the response of HDL cannot be regarded as simply part of a secondary negative acute phase reaction. After adjustment for changes in plasma volume, the data indicated that hepatobiliary dysfunction was probably a major factor in the negative response of HDL following acute pancreatitis and may have contributed to its response following myocardial infarction.

Acute-Phase Reaction↗
PubMed1987

An evaluation of three adaptive hearing aid selection strategies.

Paired-comparison judgments of intelligibility of speech in noise were obtained from eight hearing-impaired subjects on a large number of hearing aids simulated by a digital master hearing aid. The hearing aids which comprised a 5 X 5 matrix differed systematically in the amount of low-frequency and high-frequency gain provided. A comparison of three adaptive strategies for determining optimum hearing aid frequency-gain characteristics (an iterative round robin, a double elimination tournament, and a modified simplex procedure) revealed convergence on the same or similar hearing aids for most subjects. Analysis revealed that subjects for whom all three procedures converged on the same hearing aid showed a single pronounced peak in the response surface, while a broader peak was evident for the subjects for whom the three procedures identified similar hearing aids. The modified simplex procedure was found to be most efficient and the iterative round robin least efficient.

Adult↗
PubMed1986

A digital master hearing aid.

The use of computer simulation in evaluating conventional and experimental hearing aids is described. Two illustrative examples are provided. The first involves the simulation of a conventional master hearing aid and its application in evaluating different adaptive strategies in the prescriptive fitting of hearing aids. The second example involves the simulation of an experimental hearing aid embodying modern digital signal-processing techniques for the reduction of background noise. A high-speed array processor is used in order to accomplish these simulations in real time.

Computers↗
PubMed1985

Photolysis products of 2,4,5,2',4',5'-hexabromobiphenyl: hepatic microsomal enzyme induction and toxicity in Sprague-Dawley rats.

The irradiation of 2,4,5,2',4',5'-hexabromobiphenyl (2,4,5-HBB) by ultraviolet light created a mixture of lower brominated polybrominated biphenyl (PBB) congeners. Three photoproducts, 2,4,5,3',4'-pentabromobiphenyl (-PBB), 2,4,5,2',5'-PBB, and 3,4,3',4'-tetrabromobiphenyl (3,4-TBB), as well as 2,4,5-HBB and the photolyzed 2,4,5-HBB mixture, were administered to rats as a single ip injection (90 mg/kg, except 3,4-TBB, which was given at 2 mg/kg) 2 weeks before sacrifice. All treatments except 3,4-TBB induced NADPH-cytochrome P-450 reductase and aminopyrine-N-demethylase activities while all treatments except 2,4,5-HBB induced ethoxyresorufin-O-deethylase and UDP-glucuronosyltransferase activities. Thymus to body weight and spleen to body weight ratios were unchanged compared to controls for all treatments whereas an increase in the liver weights was observed for all treatment groups. Histologic examination revealed that the photolyzed 2,4,5-HBB mixture caused moderate to severe hepatocyte enlargement. Results of tissue analysis for the pure PBB congeners indicated that 2,4,5,2',5'-PBB and 3,4-TBB were metabolized in vivo and this was confirmed by in vitro metabolism studies. The results revealed that the photolyzed 2,4,5-HBB mixture caused a mixed-type induction of hepatic drug-metabolizing enzymes. This is most likely due to the effect of 2,4,5-HBB and toxic congeners formed during the irradiation of 2,4,5-HBB. 2,4,5,3',4'-PBB, which is toxic and apparently not metabolized, is believed to be the major congener contributing to the increased toxicity of the photolyzed 2,4,5-HBB mixture since 3,4-TBB was metabolized and appeared not to be as potent as inducer of aryl hydrocarbon hydroxylase activity.

Adipose Tissue↗
PubMed1985

A history of acute suppurative otitis media and allergic symptomatology in children with chronic secretory otitis media and controls.

The parents of children with secretory otitis media and the parents of healthy children attending for routine school or community medical examinations have been questioned about previous acute otitis media, aural discharge, chronic nasal symptoms and allergic disorders. Eighty-nine pairs of children, matched for age and sex, were available for analysis. There was a significantly higher incidence of acute otitis media, aural discharge and chronic nasal symptoms in the secretory otitis group (P = less than 0.001). Amongst the allergic symptoms and disorders, the only significant differences demonstrated were for drug allergy, eye itching and eye running (P = less than 0.05). The results confirm that a relationship exists between acute otitis media and secretory otitis media and also support the conventional image of the child with secretory otitis as a mouth breather with nasal symptoms. They do not lend support to the view that allergy is an important factor in the pathogenesis of secretory otitis.

Acute Disease↗
PubMed1984

Isolation and identification of piperacillin amide as an impurity in piperacillin.

Piperacillin amide (IV) was successfully identified as the predominant impurity in commercial lots of piperacillin monohydrate (III). The impurity was isolated via a preparative liquid chromatographic scheme utilizing Florisil as the adsorbent and a mobile phase of water-acetonitrile (4:96, v/v). The isolated component had nearly the same reverse-phase HPLC properties as piperacillin and was chemically and thermally unstable. This labile impurity was spectroscopically identified by field desorption (FD), fast atom bombardment (FAB) with collision activation decomposition (CAD), and desorption chemical ionization (DCI) mass spectrometries , and NMR and IR spectrometries . Identity was confirmed on comparison of the chromatographic and spectrometric data of the impurity with an independently synthesized sample of piperacillin amide.

Chemical Phenomena↗
PubMed1984

Hexosaminidase: a biochemical marker for necrotizing enterocolitis in the preterm infant.

To evaluate hexosaminidase as a biochemical marker for the early detection of necrotizing enterocolitis in preterm infants, 33 preterm infants without necrotizing enterocolitis and 18 preterm infants with necrotizing enterocolitis had hexosaminidase activity measured during the course of their hospitalization. Although hexosaminidase activity could not identify those preterm infants with necrotizing enterocolitis who had impending perforation, the data strongly suggest that measurements of serum hexosaminidase activity may provide an early biochemical indication of the presence of necrotizing enterocolitis in the preterm infant. Hopefully, early detection of necrotizing enterocolitis in these infants will reduce the morbidity and mortality of this disease.

Clinical Enzyme Tests↗
PubMed1984

Relationship between acute suppurative otitis media and chronic secretory otitis media: role of antibiotics.

A total of 204 chronic middle ear effusions from 122 children have been studied. Bacteria were isolated from 30 effusions. The commonest species found were Strep. pneumoniae and H. influenzae. These are also the commonest organisms causing acute otitis media (AOM). A similar pattern of serotypes was also demonstrated. In vitro sensitivity testing showed that most of the organisms isolated were sensitive to most commonly-used antibiotics. The main exception was resistance to penicillin amongst strains of H. influenzae and Staph. aureus. It is suggested that some cases of chronic secretory otitis media (SOM) may arise as a result of incomplete resolution of AOM and that the use of penicillin to treat AOM may be one factor in this process.

Acute Disease↗