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Biomedical subjects

M Miller

Publications and source records attributed to M Miller.

At least 595 records · Page 33Linked to original sources
PubMed1989

Morbidity for survivors of extracorporeal membrane oxygenation: neurodevelopmental outcome at 1 year of age.

Extracorporeal membrane oxygenation is an important technology in the treatment of high-risk infants whose long-term outcome is being followed prospectively at our institution. The extracorporeal membrane oxygenation procedure allows temporary cardiopulmonary support for critically ill full-term neonates who are refractory to maximum ventilatory and medical management as a consequence of severe persistent pulmonary hypertension. The technique necessitates both the permanent ligation of the right common carotid artery and jugular vein and systemic heparinization. The survivors constitute a unique group of high-risk infants, from the standpoint of the hypoxic-ischemic insults preceding extracorporeal membrane oxygenation and the risks associated with the procedure. Our results indicate that most of our survivors are developing normally at 1 year. Major morbidity, in terms of either significant developmental delay (Bayley mental and motor indices less than 70) or significant neuromotor abnormality, occurred in only 10% of these infants. Poor outcome was associated with major intracranial hemorrhage and chronic lung disease. Ligation of the right carotid artery and jugular vein was not associated with a consistent lateralizing lesion. Long-term follow-up through school age is essential.

Asphyxia Neonatorum↗
PubMed1989

Effects of Moraxella bovis and culture filtrates on 51Cr-labeled bovine neutrophils.

The cytotoxicity of Moraxella bovis whole cells and culture filtrates was studied, using 51Cr-labeled bovine and human blood neutrophils. The cytotoxicity of living M bovis was directly related to the concentration of bacteria in the neutrophil cultures, and was maximal at an approximate neutrophil to bacteria ratio of 1:10. Cytotoxicity was maximal by 30 minutes after living bacteria were added to the suspension of the 51Cr-labeled neutrophils. Expression of the cytotoxicity was dependent on the presence of Ca2+ in the media, and was independent of the presence of Mg2+. Cytotoxic activity was eliminated by inactivating M bovis in buffers containing formalin or sodium azide. Hemolytic and nonhemolytic isolates of M bovis were examined for cytotoxic activity. All 7 of the hemolytic isolates were cytotoxic for bovine neutrophils, but all 4 of the nonhemolytic isolates were devoid of cytotoxic activity. None of the 11 isolates were cytotoxic for human neutrophils. Sterile filtrates from 6-hour shaker cultures of a hemolytic M bovis isolate were cytotoxic for bovine neutrophils. Cytotoxicity of the filtrate was eliminated by heating, incubation with trypsin, or addition of EDTA to the media. Bacterial homogenates or sterile filtrates prepared from statistically incubated cultures of M bovis were not toxic for bovine neutrophils.

Animals↗
PubMed1988

Ergometrine--a partial agonist at 5-HT receptors in the uterus isolated from the oestrogen-primed rat.

The mechanism of action of ergometrine has been studied in isolated uterus from the oestrogen-primed non-pregnant rat. Ergometrine (30 nM-1 microM) induced spasm and was antagonised selectively by methysergide and ICI 169,369, a proposed competitive antagonist at 5-hydroxytryptamine (5-HT2) receptors. The pA2 values of ICI 169,369 against 5-HT and ergometrine were not significantly different. Ergometrine (0.1-10 microM) was also a selective antagonist of 5-HT with no effect against acetylcholine or potassium chloride. It is suggested that ergometrine is a partial agonist involving 5-HT receptors in rat uterus.

Animals↗
PubMed1988

Effect of growth temperature on membrane dynamics in a thermophilic cyanobacterium: a spin label study.

A strain of Synechococcus sp. was grown at its optimal growth temperature (58 degrees C) and at 38 degrees C, in order to investigate possible adaptations of membrane-related properties to growth temperature. Light-induced electron transport in thylakoid membranes from both types of cells showed linear Arrhenius plots with the same activation energy (48 kJ/mol). Membranes from cells grown at 58 degrees C had a higher temperature optimum (53 degrees C) than those from cells grown at 38 degrees C (41 degrees C). Growth at 38 degrees C caused an increase in the proportion of unsaturated fatty acids compared to growth at 58 degrees C. The fluidity of the membranes was investigated by measuring the temperature dependence of the parameters derived from electron spin resonance spectra of the spin-labels 5-doxyldecane, 5-doxylstearate and 16-doxylstearate. Only small differences between the dynamic properties of the membranes from cells grown at different temperatures could be detected. This suggests that the observed change in fatty acid composition of the membranes following the change in growth temperature does not serve to maintain a constant viscosity at the growth temperature.

Carotenoids↗
PubMed1988

Crystal structure of 15-mer DNA duplex containing unpaired bases.

Errors during DNA replication or repair can lead to the presence of unpaired or inserted bases in the double helix, as well as to mismatched base pairs. So far only structures of the latter type have been characterized by X-ray crystallography. We report here a 3-A crystal structure of DNA 15-mer d(CGCGAAATTTACGCG), which forms a duplex with two unpaired adenine residues looped outside the B-type helix. This arrangement is in disagreement with the nuclear magnetic resonance spectroscopy results for the same 15-mer in solution, indicating polymorphic nature of the structure adopted by this sequence.

Adenosine↗
PubMed1988

Structures of amidohydrolases. Amino acid sequence of a glutaminase-asparaginase from Acinetobacter glutaminasificans and preliminary crystallographic data for an asparaginase from Erwinia chrysanthemi.

The complete amino acid sequence of a glutaminase-asparaginase from Acinetobacter glutaminasificans, for which a preliminary tertiary structure is available from crystallographic analysis, has been determined by automated Edman degradation of fragments produced by chemical and proteolytic cleavages. The protein consists of 331 amino acid residues and has a molecular weight of 35,500. The pattern of hydrophilic and hydrophobic regions is typical of a globular protein. A new crystal form of an Erwinia chrysanthemi 1125 asparaginase is reported. The space group is monoclinic C2, with unit cell parameters of: a = 107.8, b = 91.7, c = 129.2 A and beta = 91.7 degrees. A Vm of 2.25 A3/dalton was calculated for one tetramer of 35,100-dalton subunits per asymmetric unit. X-ray intensity data have been obtained to 2.2 A resolution. The point group symmetry of the Er. chrysanthemi tetramer is 222 from self-rotation function calculations. The relative orientations of an A. glutaminasificans glutaminase-asparaginase model and the Er. chrysanthemi asparaginase tetramer have been determined with the cross-rotation function, and translation function calculations have revealed a plausible location for the asparaginase tetramer in the crystal.

Acinetobacter↗
PubMed1988

Campylobacter pylori infection in patients undergoing endoscopy in Fiji.

Forty two patients (20 Fijian and 22 Indian) presenting for endoscopy at the Colonial War Memorial Hospital, Suva, Fiji, were biopsied to detect Campylobacter pylori infection. Detection of the organism's urease activity in biopsy material or seeing the organism in Warthin-Starry silver stained histology sections were used to diagnose infection. Thirty-nine patients (93%) were infected; 19 of 20 Fijians (95%) and 20 of 22 Indians (91%). Of the 39 infected patients, 37 (95%) had chronic active gastritis and 24 (62%) had active peptic ulcer disease. The implications of these findings in relation to the management of endoscopy patients in Fiji are discussed.

Adult↗
PubMed1988

Effects of cyclocryotherapy on aqueous humor dynamics in cats.

The effects of graded cyclocryotherapy were studied using pneumatonometry, fluorophotometry, and light and electron microscopy. Cats were treated with either 90 degrees, 180 degrees, or 270 degrees of cyclocryotherapy and were followed up for six weeks. The response of the eyes to treatment was evaluated in terms of intraocular pressure (IOP) response, aqueous humor flow rate, and permeability of the blood-aqueous barrier compared with the untreated fellow eye. The average IOP response was determined to be -20%, -44%, and -47% for the 90 degrees, 180 degrees, and 270 degrees treated eyes, respectively. The aqueous humor flow rate was estimated to be -14%, -44%, and -52% for each of the groups, respectively. Finally, the permeability of the blood-aqueous barrier, measured 60 minutes after injection of fluorescein, was estimated to be a percent increase of 22%, 332%, and 285% for each of the groups, respectively. Histologically, the maximally treated eyes (270 degrees) demonstrated greater disruption of the ciliary body compared with the control eyes. Thus, graded cyclocryotherapy causes graded destruction of the ciliary epithelium and proportionally related changes in IOP and aqueous humor dynamics.

Animals↗
PubMed1988

Neuropsychological deficits in obligatory heterozygotes for metachromatic leukodystrophy.

Two groups of heterozygotes, one for metachromatic leukodystrophy (MLD) and the other for Tay-Sachs disease, were given a battery of neuropsychological tests, a standard neurological examination, and an EEG. Neurological and EEG findings were unremarkable for both groups. The MLD heterozygotes showed deficits in the neuropsychological tests involving spatial or constructional components, but not in tests involving language skills. The Tay-Sachs heterozygotes showed no consistent deficit on any component of the neuropsychological tests.

Electroencephalography↗
PubMed1988

Prevalence and recognition of alcohol abuse in a primary care population.

PURPOSE: The purpose of this study was to assess the prevalence, physician recognition, and treatment of alcohol abuse among patients of 19 senior medical residents practicing in a hospital-based, primary care setting. PATIENTS AND METHODS: Interviews of 242 outpatients were conducted, and alcohol abuse and dependence, as defined by the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III), were determined using the Diagnostic Interview Schedule. RESULTS: Twenty percent of the patients studied had abused or were dependent on alcohol at some time in their lives and 5 percent reported abuse or dependence within the last year. Of the techniques studied, a short screening questionnaire (Short Michigan Alcohol Screening Test [SMAST]) was the most accurate way of identifying patients who abused alcohol, and physician assessments were more accurate than laboratory tests. Although the physicians were aware of serious alcohol problems among 77 percent of their patients who met DSM-III criteria for alcohol abuse or dependence in the previous year, they identified only 36 percent of their patients with less serious problems or past alcohol abuse. They had only discussed alcohol abuse with 67 percent of the patients they identified as alcohol abusers. CONCLUSION: We conclude that a short screening questionnaire (SMAST) is an accurate means of identifying alcohol abuse. Despite the recognition of serious alcohol problems by the physicians, the problem is not addressed routinely even among patients that are recognized as alcoholic.

Alcoholism↗
PubMed1988

Pregnancy delays paracetamol absorption and gastric emptying in patients undergoing surgery.

Gastric emptying may be delayed during pregnancy by hormonally mediated relaxation of the musculature of the stomach and by mechanical effects. In the present study, the rate of paracetamol absorption was used to measure gastric emptying in 14 non-pregnant women undergoing minor gynaecological surgery, and in 28 women undergoing termination of pregnancy. Of the pregnant patients 16 were of 8-11 weeks gestation and 12 were 12-14 weeks gestation. Paracetamol absorption was delayed in those who were 12-14 weeks pregnant compared with non-pregnant controls. Paracetamol absorption in the 8-11 weeks pregnant group was between the other two groups, but was not significantly different from either.

Acetaminophen↗
PubMed1988

Intertester reliability and concurrent validity of fluid-based and universal goniometers for active knee flexion.

This study was designed 1) to determine the intertester reliability of the universal goniometer and the fluid-based goniometer and 2) to establish the concurrent validity of the fluid-based goniometer. Two testers measured active knee flexion of 20 healthy subjects (15 women, 5 men) using both instruments. The subjects had a mean age of 24.8 years (s = 5.5) and reported no previous history of pathological conditions of the right lower extremity. Using a correlational design, high intertester reliability was established for each instrument (universal goniometer, r = .87; fluid-based goniometer, r = .83). The concurrent validity of the fluid-based goniometer was also good for both testers (tester A, r = .83; tester B, r = .82). When the data were subjected to t tests, significant differences were found between the instruments for each tester (p less than .05). The results suggest that similar measurements will be obtained between therapists using the universal and fluid-based goniometers; however, the two instruments cannot be used interchangeably in the clinic.

Adult↗