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Biomedical subjects

R D Taylor

Publications and source records attributed to R D Taylor.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of age on congruence between adults' and youths' ratings of life event stressors.

Life event stressors were rated by 60 sixth grade students from their personal points-of-view and by two adult samples (ns = 11 and 17) on the basis of how they believed a typical 12- to 14-yr.-old today would rate events. Ratings of adults and sixth grade youth indicated strong congruence and were significantly different from the rating relationship previously reported between adults and ninth grade students. Adults' familiarity with youth strengthened but did not significantly improve congruence of ratings.

Adolescent↗
PubMed1987

A novel binding assay for phospholipase A2.

We have devised a rapid and simple assay for estimating the binding of pancreatic phospholipase A2 to a bilayer lipid membrane. The binding was observed to be extremely rapid at 37 degrees and was absolutely dependent upon Ca2+. Amongst several drugs known to inhibit the catalytic activity of phospholipase only mepacrine at high concentrations (500 microM) and chlorpromazine (100 microM) were active. Treatment of the enzyme with p-bromophenacylbromide did not inhibit binding. Several alcohols potentiated binding whereas detergents tended to inhibit. Amongst several purified proteins tested, only the steroid-induced anti-phospholipase protein lipocortin prevented binding. The use of this assay in screening for antiphospholipase agents is discussed.

Binding Sites↗
PubMed1987

Double-blind comparison of half-dose and standard-dose flupenthixol decanoate in the maintenance treatment of stabilised out-patients with schizophrenia.

A double-blind controlled trial of 50% dose reduction in maintenance treatment in stable out-patients with low BPRS scores and good social function shows a significantly higher relapse rate in the low-dose group at 12 months (P less than 0.05). After an interval of 24-36 months from dose reduction, 56-76% had experienced a relapse and 76-79% had resumed their former dosage. No clear advantage was shown for the lower dose in either a reduction of side-effects or improved social function, but a reduced prevalence or lower rate of symptom emergence for tardive dyskinesia was suggested.

Adult↗
PubMed1986

Expression of troponin T in atria and ventricles of avian and mammalian hearts.

The expression of troponin T in atria and ventricles of adult chicken, rabbit and beef hearts has been studied by two dimensional electrophoresis of soluble extracts from these tissues. The monoclonal antibody, T1/61, has been used to detect the presence of troponin T in the chicken samples. In the chicken only one form of troponin T has been found which is resolved into two spots that probably are due to phosphorylated and non phosphorylated forms. The gels of chicken atria and ventricles are identical with the same patterns, not only of troponin T but also of tropomyosin and myosin light chains. In rabbit and beef the position of troponin T can be located by comparison with the chicken. In the beef it is possible that two forms are present but in the rabbit there appears to be only one. The gels of atria and ventricles of rabbit and beef hearts show differences only in the myosin light chains whereas the expression of tropomyosin is the same. In beef, beta-tropomyosin is found in both tissues. On the evidence of these gels there are no differences in the expression of troponin T or tropomyosin between the atria and ventricles of any of the hearts studied.

Animals↗
PubMed1986

Rapid sample preparation and high performance liquid chromatographic determination of total and unbound serum disopyramide.

A rapid sample preparation procedure, which requires no solvent extraction or concentration, for the high performance liquid chromatographic (HPLC) determination of disopyramide is described. The chromatography is performed on a C-18 radial compression mu-Bondapak column and detection by absorbance at 254 nm with a run time of 12 min. The mobile phase is 10 mM sodium acetate (pH 4.5)/acetonitrile (3:1 vol/vol). For the total drug assay, 50 microliter 30% (wt/vol) trichloroacetic acid is added to 500 microliter serum, which causes the precipitation of protein. Following centrifugation, 100 microliter of supernatant is mixed with 25 microliters of internal standard (25 micrograms/ml, ethyl p-aminobenzoate), and 50 microliters of this mixture is injected into the HPLC. Unbound disopyramide is separated from protein-bound drug by filtration with an Amicon Centrifree filter, which removes 99.6% of protein and does not retain disopyramide. To 100 microliters of this filtrate is added 25 microliters of internal standard, and 50 microliters is injected into the HPLC. The assay is linear to at least 20 micrograms/ml. The total drug assay shows an average recovery of 93.0% with an average coefficient of variation (CV) of 3.4%. The unbound drug assay shows an average CV of 4.1%. The percentage of free drug in a sample containing 4.85 g/dl protein varies from 68.0 to 83.5% at concentrations of 2.5-10 micrograms/ml, which illustrates the concentration-dependent nature of the protein binding, and the need to measure the unbound fraction of drug. Of 31 drugs tested for interference, none was found to interfere.

Chromatography, High Pressure Liquid↗
PubMed1985

Effect of mucous glycoprotein on nucleation time of human bile.

The purpose of this study was to determine whether mucous glycoprotein is the nucleating factor responsible for the rapid in vitro nucleation time of gallbladder bile from persons with cholesterol gallstones. Ultracentrifugation and ultrafiltration of abnormal bile removed all detectable mucous glycoprotein, yet bile that had been filtered exhibited as rapid a nucleation time as unfiltered bile. When abnormal bile was heated to 95 degrees C for 60 min, nucleation time was significantly prolonged. Rapid nucleation time could be restored to heated abnormal bile by addition of small volumes of unheated bile. Purified human mucous glycoprotein accelerated nucleation time of human bile, but mucous glycoprotein from control patients was as effective as that from gallstone patients. There was a direct relationship between mucous glycoprotein concentration and effect on nucleation time. Mucous glycoprotein may be important in the early stages of stone formation, but it is probably not the agent responsible for the sharp discrimination between control bile and gallbladder bile from patients with cholesterol stones found in the in vitro nucleation time test. The markedly prolonged nucleation time of heated abnormal bile is preliminary evidence that the nucleating factor may be a heat-labile protein other than mucous glycoprotein.

Adult↗
PubMed1983

The discontinuance of maintenance neuroleptic therapy in chronic schizophrenic patients: drug and social consequences.

In a prospective follow-up the outcome of 60 chronic schizophrenic patients who discontinued neuroleptic therapy after remaining stable 12-48 months was compared with controls continuing medication. Not only did the drug-discontinued patients have more relapses (P less than 0.001), but the form of relapse was both more severe and acute, resulting in differences of self-injury (P less than 0.05), anti-social behaviour (P less than 0.01), inpatient admissions (P less than 0.001), and the use of compulsory powers (P less than 0.01). In patients who relapsed, both social and work function was affected adversely for some months. Patients who remained relapse-free without drugs (20%) had a level of work and social function similar to medicated patients. At the end of 18 months the patients who discontinued depot maintenance therapy were found to have been prescribed one-third more neuroleptic drugs than controls, with a possible increase in the risk of long-term tardive dyskinesia.

Adult↗
PubMed1983

Evidence for a potent nucleating factor in the gallbladder bile of patients with cholesterol gallstones.

A study was performed to determine whether the rapid nucleation time of gallbladder bile obtained from patients with cholesterol gallstones was due to the addition of a nucleating agent or the removal of an antinucleating agent by the gallbladder. Isotropic phases of gallbladder bile from normal controls (control bile) and from patients with gallstones (abnormal bile) were mixed 50:50 (vol/vol) and the nucleation times of the mixtures and parent biles were determined. The mixtures had rapid nucleation times, similar to those of the gallbladder bile from gallstone patients, indicating that a nucleating factor was present in the abnormal bile. Experiments were then performed using mixtures in which the proportion of abnormal bile was reduced. These studies showed that the nucleating agent was potent. The results were not due to changes in cholesterol saturation or total lipid concentration. The conclusions reached in the first study were supported in a second set of similar experiments in which hepatic bile from gallstone patients was mixed with their own gallbladder bile. It was also found that filtration of abnormal bile through an XM-300 Amicon filter did not eliminate its nucleating potency, indicating that the results could not be explained by the presence of residual microcrystals in the abnormal bile.

Bile↗
PubMed1981

A protein in urine associated with muscle disease and muscle damage.

Analysis of the protein composition of human urine by high-resolution two-dimensional electrophoresis showed that several features are associated with neuromuscular diseases, the best defined being the appearance in the urine of a small amount of a protein that migrates on the electropherogram as a characteristic spot (spot C). This spot consists of a protein of apparent molecular weight 26 000 and isoelectric point 5.3. The spot was usually present in the urine of patients suffering from diseases in which the musculature was directly affected but was rarely found in other patients and normal subjects. The protein responsible for spot C appears to be an index of muscle damage caused by a number of conditions. Attempts are being made to isolate enough of the protein to permit its identification.

Adolescent↗
PubMed1981

Reproducibility of left ventricular internal dimensions with M mode echocardiography: effects of heart size, body position and transducer angulation.

Analysis was made of the variables of heart size, body position and transducer angle affecting the reproducibility of left ventricular internal dimensions as measured with M mode echocardiography. Echocardiograms were recorded in 24 subjects as the thorax was incrementally rotated and tilted. Transducer angle was noted from a three plane level attached to the probe. Constants were the technician, transducer placement and the interpreter. Heart rates varied insignificantly; respirations were held. Groups A and B were defined by their initial left ventricular internal dimensions at end-diastole (LVIDd): 49 +/- 5.9 and 73 +/- 8.6 mm (group mean +/- standard deviation). With body position constant the measurement error between duplicate recordings of LVIDd was +/- 1.2 mm (coefficient of variation = 1.8 percent) in Group A and +/- 4.5 mm (coefficient of variation = 4.6 percent) in Group B (p less than 0.001). Transducer angle varied 12 degrees between duplicate recordings in both groups. As the position of the thorax changed, the transducer followed, maintaining approximately the same incline with the chest wall. In both groups errors for combined LVIDd recorded with rotation and tilt, respectively, were unchanged from the duplication error. Thus, when the spatial orientation between the transducer and heart is held constant, it is the size of the heart that determines the reproducibility of the measurement of left ventricular internal dimensions.

Cardiac Volume↗
PubMed1981

Abnormal mitral valve coaptation in hypertrophic obstructive cardiomyopathy: proposed role in systolic anterior motion of mitral valve.

Two dimensional echocardiographic evaluation utilizing the apical four chamber and apical long axis views was made in 10 normal subjects and 35 patients with hypertrophic cardiomyopathy, including 16 without and 19 with systolic anterior motion of the mitral valve. Mitral valve leaflets were imaged throughout the cardiac cycle. The normal subjects and the patients with hypertrophic cardiomyopathy without systolic anterior motion demonstrated mitral valve coaptation that seemed to involve the distal tip of the anterior leaflet. In contrast, patients with hypertrophic cardiomyopathy with systolic anterior motion demonstrated abnormal coaptation, so that the posterior leaflet coapted with a mid portion of the anterior leaflet, leaving a distal "residual" anterior leaflet in the left ventricle during systole. A sharp angulation of this distal leaflet in mid systole toward the interventricular septum is thought to represent systolic anterior motion. It is speculated that abnormal mitral leaflet coaptation in necessary for development of leaflet systolic anterior motion, which is correlated with dynamic left ventricular outflow gradients in hypertrophic obstructive cardiomyopathy.

Adult↗
PubMed1981

Proteins in the urine associated with Duchenne muscular dystrophy and other neuromuscular diseases.

1. Up to 200 protein staining spots could be detected on two-dimensional electrophoresis of urine from healthy persons. Other minor spots were occasionally present. 2. Although the electropherograms exhibited constant characteristic features some variation in protein pattern was observed between individuals and with a given individual at different times. 3. Two additional proteins, spots C and D, were consistently present in urine from boys with Duchenne muscular dystrophy. Spot C was also present in the urine of about 60% of obligatory carriers of this dystrophy. 4. The protein responsible for spot C had a molecular weight of 26000 and an isoelectric point of 5.3. 5. Spot C was also detected in the urine of patients with other neuromuscular conditions. Neither spot C nor spot D could be detected in the urine of patients with physical disabilities other than those of neuromuscular origin. 6. It is concluded that the urinary excretion of spot C, and probably of spot D, is a consequence of muscle damage and that their detection has potential as a diagnostic tool.

Adolescent↗
PubMed1980

An automated flow-temperature-humidity control system.

An automated system that controls air flow, temperature, and humidity has been developed from a commercially available temperature=humidity indicator and a specially built flow-temperature-humidity control module. Parameters are set using direct-reading dials on the control module. The air flow is maintained using a mass-flow controller while process controllers connected to the indicator regulate humidity and temperature. The system will run indefinitely without need for operator intervention. If the module and indicator are calibrated properly, accurate air flows (+/- 2% of full scale), temperatures (+/- 0.3 degrees C), and humidities (+/- 2% RH) can be achieved.

Environment, Controlled↗
PubMed1979

M mode and cross-sectional echocardiographic features of flail posterior mitral leaflets.

Seventeen patients with accepted M mode echocardiographic criteria for flail mitral leaflet were studied. M mode echocardiograms revealed characteristic disordered mitral valve motion: (1) 16 (94 percent) had chaotic diastolic mitral motion; (2) 14 (82 percent) had systolic mitral flutter; (3) 14 (82 percent) had systolic left atrial echoes; and (4) 12 (71 percent) had systolic mitral valve prolapse. In 8 patients (47 percent) all four findings were present, with three findings present in 16 (35 percent) and two findings present in 13 (18 percent); none had fewer than two findings. Cross-sectional echocardiographic studies in 10 patients revealed a systolic whipping motion of the posterior mitral leaflet into the left atrium in all, abnormal systolic mitral coaptation in all and an abnormal mass of systolic left atrial echoes in 4. None of the first three M mode criteria were observed in 230 patients with uncomplicated "mid systolic click-late systolic murmur" syndrome; cross-sectional echocardiography in 30 of 230 patients revealed normal systolic mitral coaptation and no systolic whipping of the tip of the posterior mitral leaflet into the left atrium.

Adolescent↗
PubMed1978

Enhancement of air filtration using electric fields.

Although polarized electrostatic air filters are efficient air filtrating devices, their main disadvantages are difficulty in collecting conductive particles or in operating at relative humidities above 70%. We describe here a new filter design that eliminates these problems. A nonconductive media, normally a glass fiber mat, is placed between two insulated conductive screens. As the voltage across the screens is increased, the penetration of particles decreases exponentially. Increasing the electric field from 0 to 10 kV/cm will decrease the mass penetration from 60% to less than 10% of a polydispersed 0.8 micrometer ammd(sigma g = 2.0) sodium chloride aerosol. The experimental effects of face velocity, particle charge and size, packing density, fiber size, and screen insulation mirror the theoretical effects of these variables on particle penetration.

Air Conditioning↗