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Biomedical subjects

E White

Publications and source records attributed to E White.

At least 271 records · Page 15Linked to original sources
PubMed1989

Determination of serum cholesterol by a modification of the isotope dilution mass spectrometric definitive method.

An isotope dilution mass spectrometric (ID/MS) method for cholesterol is described that uses capillary gas chromatography with cholesterol-13C3 as the labeled internal standard. Labeled and unlabeled cholesterol are converted to the trimethylsilyl ether. Combined capillary column gas chromatography and electron impact mass spectrometry are used to obtain the abundance ratio of the unlabeled and labeled [M+.] ions from the derivative. Quantitation is achieved by measurement of each sample between measurements of two standards whose unlabeled/labeled ratios bracket that of the sample. Seven pools were analyzed by this method: standard reference material (SRM) 1951, which consists of three frozen serum pools with low, medium, and high levels of cholesterol; SRM 1952, which consists of three freeze-dried serum pools with low, medium, and high levels of cholesterol; and SRM 909, a freeze-dried serum pool. The method is a modification of our original definitive method for cholesterol. The modified method uses much better chromatographic separations to assure specificity and a new method of implementing selected ion monitoring on a magnetic mass spectrometer to obtain high-precision measurements of ion intensity ratios on narrow gas chromatographic peaks. The modified method has a coefficient of variation (CV) of 0.22%, which is an improvement over the original method's CV of 0.36%. The measurements were found to be free of interference. The high precision and absence of bias qualify this method as a candidate definitive method.

Cholesterol↗
PubMed1989

Specific disruption of intermediate filaments and the nuclear lamina by the 19-kDa product of the adenovirus E1B oncogene.

The 19-kDa protein encoded within the adenovirus E1B gene is essential for transformation by adenovirus and for proper regulation of viral early gene transcription. In order to investigate the biological function of the 19-kDa E1B protein, vectors were constructed to produce the 19-kDa protein in mammalian cells under the direction of heterologous promoters. Surprisingly, during transient expression, the E1B 19-kDa protein specifically associated with and disrupted the organization of intermediate filaments and the nuclear lamina, without disturbing the organization of other cytoskeletal networks. These results directly demonstrate an effect of a viral transforming protein on the cytoskeleton and suggest a role for intermediate filaments and the nuclear lamina in modulation of viral gene expression and the process of oncogenic transformation.

Adenovirus Early Proteins↗
PubMed1989

Cancer incidence among native Americans of western Washington.

The incidence of cancer among Native Americans in Alaska, Canada, and the south western United States has been reportedly low relative to the Caucasian populations in these areas. We investigated the incidence of cancer among the Native Americans of Western Washington for the time period 1974-1983 and compared it to that of the Caucasian population using two types of analyses, age-standardized incidence ratios (SIR) and proportional cancer incidence ratios (PIR). Native Americans of this area were found to be at lower risk of cancer than Caucasians at almost all ages. The age-standardized incidence ratio (SIR) for all cancer sites was 0.4 (p less than 0.01) for males and 0.6 (p less than 0.01) for females. A relative excess of cancer of the cervix (SIR = 1.6, PIR = 2.1, p less than 0.05) was found among Native American females. Significant deficits were found for corpus uterine cancer among females (SIR = 0.2, PIR = 0.5, p less than 0.05) and cancer of the prostate among males (SIR = 0.2, PIR = 0.5, p less than 0.05). A suggestive increase in the risk of cancer of the gallbladder was discovered for males and females. This is the first report on cancer incidence among Native Americans in Western Washington.

Adolescent↗
PubMed1989

Chinese whispers: the folklore of community psychiatric nursing manpower planning targets.

The relatively recent establishment of manpower planning targets for community psychiatric nursing services in England are traced to their origins in 1976. The original mathematics are reworked and differences are found. Methodological and substantive issues which flow from the findings are discussed, both in relation to post-basic nurse education in general and for future planning of community psychiatric nursing in particular. Future research directions are suggested.

Community Mental Health Services↗
PubMed1989

Mechanisms and significance of calcium entry at positive membrane potentials in guinea-pig ventricular muscle cells.

Possible mechanisms for calcium entry at positive membrane potentials were investigated in single cells isolated from guinea-pig ventricular muscle. The cells were voltage clamped and contraction was measured by an optical technique. When prolonged (200 ms to 2 s) depolarizations at +60 mV were applied, contraction amplitude increased with pulse duration, in contrast to the contraction at 0 mV. When a 'pre-pulse' to 0 mV was applied for 200 ms to inactivate current through 'L-type' calcium channels, contraction nevertheless increased with membrane potential during a subsequent test pulse applied over the range -40 to +60 mV. Contraction during the test pulse at +60 mV was abolished when extracellular calcium was reduced to zero. This effect developed more rapidly than abolition of the contraction in response to the pre-pulse to 0 mV. Reduction of extracellular calcium from 2.5 to 1 mM reduced the contraction at +60 mV to a greater extent than that at 0 mV and caused an inward shift in the current at +60 mV. Nifedipine (5 microM) substantially reduced the contraction during the test pulse to 0 mV but had little effect on the contraction at +60 mV. Conversely, dodecylamine (20 microM) caused little or no decrease in the contraction at 0 mV but substantially reduced the contraction at +60 mV. Following a conditioning pre-pulse to 0 mV the contraction at +60 mV was not consistently reduced by exposure to 3 microM-ryanodine. The interpolation of a single 200 ms pulse to +60 mV in a train of pulses to 0 mV potentiated the following contraction to 0 mV. This potentiation decayed over the first four steps to 0 mV following an interpolated pulse and increased with the voltage of the interpolated pulse over the range -20 to +60 mV. Potentiation was abolished on exposure to 3 microM-ryanodine. These observations are consistent with entry of calcium at positive membrane potentials through voltage-dependent, non-inactivating pathways which are insensitive to nifedipine but inhibited by dodecylamine. The observations support the hypothesis that calcium entry via this mechanism may contribute, at least under some conditions, to the loading of intracellular stores of calcium during the late plateau of the action potential, and thus influence subsequent contraction. Calcium entry through Na+-Ca2+ exchange is a possibility which would allow calcium entry to increase over the range of membrane potentials at which contraction was increased. However, additional calcium entry through other nifedipine-insensitive pathways, such as calcium-activated non-selective channels, cannot be excluded.

Amines↗
PubMed1989

Mechanism of potentiation of contraction by depolarization during action potentials in guinea-pig ventricular muscle.

Action potentials were recorded from guinea-pig ventricular cells and contraction recorded by an optical technique. When the plateau of a single action potential was depolarized (by 70-120 pA applied 100 ms after the upstroke for 100 ms), contraction associated with the following normal action potential was potentiated. This potentiation was not seen in cells exposed to 10 mM-caffeine. The observations are consistent with potentiation of subsequent contraction by increased loading of caffeine-sensitive calcium stores, as a consequence of reduced Ca2+ extrusion or possibly Ca2+ entry via Na+-Ca2+ exchange during a depolarized plateau.

Action Potentials↗
PubMed1989

Double-blind trial of imipramine in Alzheimer's disease patients with and without depression.

The authors divided 61 subjects with primary degenerative dementia of the Alzheimer's type into a group who also met DSM-III criteria for depression (N = 28) and a group who did not (N = 33). Both groups were randomly assigned to an 8-week double-blind trial of imipramine or placebo. Scores on the Hamilton Rating Scale for Depression, administered at baseline and weeks 2, 4, 6, and 8, indicated significant improvement in both groups. Two measures of cognitive function yielded differing results. The results suggest that moderate depression is a treatable condition in patients with Alzheimer's disease.

Aged↗
PubMed1989

Going in circles.

Explore the source record for details and available documents.

Hospital Bed Capacity, 500 and over↗
PubMed1988

'Revised' mass spectral identification of 2-amino-4-(5-nitro-2-furyl)thiazole metabolites.

The electron ionization mass spectra of 2-amino-4-(5-nitro-2-furyl)thiazole metabolites obtained from microsomal incubations and chemical syntheses were studied. The identities of the metabolites were established by chemical ionization, high resolution, and metastable measurements. The compounds studied showed multiple modes of cleavage, skeletal rearrangements and hydrogen back-transfer.

Animals↗