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Biomedical subjects

D Peters

Publications and source records attributed to D Peters.

At least 127 records · Page 7Linked to original sources
PubMed1985

Non-invasive oscillometric measurement of systolic, mean and diastolic blood pressure in infants with congenital heart defects after operation. A comparison with direct blood pressure measurements.

The accuracy of indirect oscillometric blood pressure measurements has been evaluated in 32 infants up to 11 months of age undergoing heart surgery. In a number of 1029 simultaneous measurements the indirect blood pressure was compared with the direct value obtained from a radial artery catheter. Cuffs of different sizes were applied. The main results were as follows: Regarding the ratio of cuff width to arm circumference, the best correlation between oscillometric and direct blood pressure measurements was obtained with a ratio of 0.38-0.41. The value of indirect blood pressure measurements depends on the absolute height of the blood pressure. In low blood pressure there is a tendency to underestimate and in high blood pressure there is a tendency to overestimate by the oscillometric blood pressure measurement. By applying an appropriate cuff size and by using our diagrams it should be possible to derive a direct value for the blood pressure on the basis of indirect oscillometric blood pressure measurements.

Blood Pressure↗
PubMed1984

[Plastic surgery of the mitral valve in mitral valve insufficiency - advantages of physiologic surgery].

Nine patients (mean age at the time of surgery 54.5 +/- 0.7 years), who had mitral valve reconstruction for mitral valve insufficiency were studied on an average of 15.0 +/- 7.5 months after the operation using technetium-99m-pertechnetate--or gold scintigraphy. The radionuclid ventriculograms were performed with the patient in RAO-position at rest and during mild exercise (50 watt). Looking at the results of the preoperatively performed heart catheterization with contrast ventriculography our datas showed a postoperative improved left ventricular function as well as a physiologic function of the mitral valve. Clinically the patients improved from class 3.6 to 1.6 (NYHA) on an average. The reconstructive mitral valve insufficiency is able to restore normal left ventricular function. The operation should be carried out on patients graded at class II (NYHA). Technetium-99m-pertechnetate scintigraphy (first pass technique) appears to be particularly suitable for evaluating left ventricular function and the function of the mitral valve after reconstructive mitral valve surgery.

Female↗
PubMed1984

Terodiline in the treatment of urinary frequency and motor urge incontinence. A controlled multicentre trial.

Terodiline is a secondary amine with antimuscarinic and calcium antagonistic properties. It has complete bioavailability from the gastro-intestinal tract and a mean elimination half-life of 60 hours. This paper describes a randomized, double-blind, two period cross-over (3 week periods) trial in women with motor urge incontinence without other neurological symptoms. The drug was given b.i.d., 12.5 mg in the morning and 25 mg at night. The trial was performed as a multicentre study and monitored by frequent site visits during the 9 months when patients entered the study. Eighty-nine patients from 19 clinics fulfilled the inclusion criteria of the protocol. Cystometrograms (CMG) (bladder capacity, volume at first desire to void, residual urine) and micturition characteristics over 3 to 7 days were measured during a one week run-in period and during the last week of each treatment period. The patients' preferences were assessed for the two treatment periods as well as vis-à-vis the run-in period. Side effects were evaluated at the end of each treatment period. There were 16 drop-outs and withdrawals during period 1 and 9 during period 2 (5 and 3 due to cystitis, 7 and 2 due to side effects, and 4 and 4 lost to follow up, respectively). During the evaluation of the data a treatment by period interaction was observed which motivated a parallel group analysis to be performed in addition to a cross-over trial analysis. Statistically significant differences in patient preferences were demonstrated (63% preferred terodiline in comparison with placebo and 69% terodiline in comparison with run-in). No statistically significant difference in incidence of side effects could be demonstrated between terodiline and placebo. Based on all data available 35% of the patients had side effects on placebo and 53% on terodiline. Twelve per cent reported dryness of the mouth on placebo and 25% on terodiline. Of the 9 patients (10%) withdrawn from the study because of side effects, 7 had terodiline as first treatment, one had placebo and one terodiline as second treatment. The frequency of voluntary micturitions decreased during period 1 from 9.6 to 8.9 (-0.7) per 24 hours on placebo and from 9.9 to 7.3 (-2.6) on terodiline. Involuntary micturitions decreased from 2.3 to 1.7 (-0.6) on placebo and from 2.5 to 1.5 (-1.0) on terodiline. The changes during terodiline were statistically significant.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

[Pheochromocytoma in pregnancy. Clinical course and therapy].

A case of pheochromocytoma in pregnancy is reported and the literature is reviewed: Maternal mortality of 48% and fetal mortality of 55% was found when pheochromocytoma complicated a pregnancy. The fact is stressed, that this high mortality could be reduced by an earlier diagnosis. In our patient the diagnosis was established in the 33rd week of gestation by means of elevated levels of urinary vanillinmandelic acids and catecholamines. It was possible to maintain pregnancy until the 38th week of gestation under treatment with phenoxybenzamin. Two weeks prior to term a healthy girl was delivered by cesarean section. Two weeks later laparotomy was performed and the tumor removed.

Adrenal Gland Neoplasms↗
PubMed1982

Characterization of ampicillin resistance plasmids from Haemophilus ducreyi.

Seven strains of Haemophilus ducreyi from diverse geographic origins were analyzed for their plasmid content. All strains were multiply resistant, but only resistance to ampicillin was transferred to Escherichia coli by transformation. The H. ducreyi plasmids encoding for ampicillin resistance were 7.4, 5.7, and 3.6 megadaltons and encoded for part or all of TnA, and ampicillin transposon. The relatedness of these plasmids was examined by restriction endonuclease digestion and DNA-DNA homology with isolated DNA fragments from TnA.

Ampicillin↗
PubMed1981

A flow system for partial automation of plating efficiency tests.

A flow system that sterilely deposits a known number of cells into a collection vessel has been constructed and evaluated. In this device, the cells from a single-cell suspension flow through a nozzle that constrains them to the center of the emerging jet. The cells in the jet are illuminated by a 0.5-mW helium-neon laser; they are detected, sized and counted on the basis of the light scattered as they pass through the laser beam. The device has been used for plating efficiency tests in a tissue culture laboratory. We found that it saved considerable labor by eliminating the dilution step from the standard plating efficiency procedure. The biologic effect of machine plating was determined by comparing plating efficiencies of KHT, CHO-T5, and CHO-AA8 cells established by hand plating with those established by machine plating. Results indicate that machine plating reduces the plating efficiency of the CHO-T5 cells while the plating efficiencies of the CHO-AA8 and KHT cells are unaffected.

Animals↗
PubMed1981

Protein composition of the virions of five plant rhabdoviruses.

Five plant rhabdoviruses fall into two groups based on the patterns produced by their dissociated virion proteins when separated electrophoretically. Lettuce necrotic yellows virus (LNVY) and Sonchus virus (SV) virions contained only one M protein and NS protein. Sowthistle yellow vein virus (SYVV), Sonchus yellow net virus (SYNV) and eggplant mottled dwarf virus (EMDV) virions contained two M proteins and no detectable NS protein. The M and G proteins of LNYV and SV were easily released from the nucleocapsid after incubation with 1% Nonidet P40 (NP40), whereas the G protein and only a proportion of one of the M proteins were released from the nucleocapsids of SYVV, SYNV and EMDV after incubation with 1% NP40. It was necessary to increase the NP40 concentration to 4% to release both M proteins from SYVV nucleocapsids.

Plant Viruses↗
PubMed1981

Multiple systems organ failure: VII. Reduction in plasma branched-chain amino acids--correlations with liver failure and amino acid infusion.

Lower fractional concentrations of branched-chain amino acids were found in trauma-septic patients who did not survive than in those who survived (p values less than or equal to 0.046 to 0.001). A liver dysfunction scale was constructed on the basis of the levels of plasma bilirubin, albumin, SGOT, prothrombin time, and neurologic encephalopathy. Increased liver dysfunction was associated with reduced plasma fractional branched-chain amino acids for all branched-chain amino acids in both the surviving and nonsurviving patients except for valine in the nonsurviving group. This decrease was statistically significant (p less than or equal to 0.041 to 0.001) for leucine and isoleucine in the nonsurvivors and for valine in the survivors. The infusion of amino acids was associated with a decrease in the fractional concentrations in the nonsurvivors for leucine while the fractional concentrations of isoleucine in the nonsurvivors and isoleucine and valine in the survivors rose. The statistically significant changes (p less than 0.018 to 0.001) were for leucine in the nonsurvivors and isoleucine and valine in the survivors. When the liver dysfunction and amino acid infusion related changes are taken in;to account there were no significant differences in the fractional branched-chain concentrations between survivors and nonsurvivors. Liver dysfunction and low fractional branched-chain amino acids were linked in magnitude in a way that is consistent with the low branched-chain amino acids producing the liver dysfunction.

Amino Acids↗
PubMed1980

Variability of dry mass as a fundamental biological property demonstrated for the case of Vaccinia virions.

The dry mass of individual vaccinia virions, as an example of a presumably uniform biological population, prepared in different lost at the Institute for Tropical Hygiene in Hamburg, was tested for variability by quantitative electron microscopy. A value of 5.26 X 10(-15) g for the median weight of the particle was calculated from 7,300 determinations. By assessing the variability of polystyrene latex spheres, which were used as mass standards, we demonstrated that the variability of dry mass of vaccinia virions is fivefold greater than the variability (standard) introduced by the method for determining mass. It was concluded that while genetic control in a presumably homozygous virion is strict with respect to quality, quantity of viral components (other than DNA) varies in fashion that can be aptly described by a log-normal distribution. It is recognized that this observation is empirically supported by the paradigm that any composite biological entity is subject to quantitative variability, the more so the heavier the individual representatives of a species are. In addition, the effects that extractions and staining have on the dry mass of vaccinia are reported, as well as is the median for the dry mass of other strains of pox viruses.

Microscopy, Electron↗
PubMed1979

Rhabdoviridae. Report of the Rhabdovirus Study Group, International Committee on Taxonomy of Viruses.

The family Rhabdoviridae comprises approximately 75 viruses infecting vertebrates, invertebrates and plants. The main characteristics of the member viruses are: (i) the viruses infecting vertebrates and invertebrates are bullet-shaped and the viruses infecting plants are usually bacilliform; (ii) the viruses have particle lengths varying from 130 to 380 nm and widths varying from 60 to 95 nm; (iii) the viruses possess unit-membrane envelopes from which protrude spikes 5 to 10 nm long; (iv) the viruses have precisely coiled helical nuecleocapsids with a diameter of approx. 50 nm; (v) most of the viruses which have been studied contain 5 proteins; the prototype, vesicular stomatitis virus, contains proteins designated L (large), G (glycoprotein), N (nucleoprotein), NS (nonstructural) and M (matrix); N or NS is phosphorylated in most members which have been studied; (vi) the viruses contain single-stranded RNA which is transcribed into several messenger RNA species with sizes corresponding to the structural proteins; (vii) the nucleocapsid contains the RNA-dependent RNA polymerase and is infectious; and (viii) many of the viruses produce morphologically distinct defective-interfering (T) particles.

RNA, Viral↗
PubMed1979

Slit-scan flow cytometry of mammalian chromosomes.

A flow cytometer has been constructed which measures total fluorescence and the distribution of fluorescence along isolated, stained mammalian chromosomes. In this device, chromosomes flow lengthwise at 4 m/sec through a 1-micrometer thick laser beam. The fluorescence from each chromosome is recorded at 10 nsec intervals; the sequence of recorded values represents the distribution of fluorescence along the chromosome and is stored in the memory of a waveform recorder. The total fluorescence of each chromosome is also measured and recorded. Preliminary studies show that doublets of 1.83 micrometers diameter microspheres flow with their long axes parallel to the direction of flow and that the two microspheres are resolved in the slit-scan profile. Ethidium bromide stained Muntjac and Chinese hamster chromosomes have also been slit-scanned. Centromeres were resolved in many of the Nos. 1 and 2 Chinese hamster chromosomes and the Nos. 1 and X + 3 Muntjac chromosomes.

Animals↗
PubMed1979

Flow cytometry of mammalian sperm: progress in DNA and morphology measurement.

Variability in DNA content and head shape of mammalian sperm are potentially useful markers for flow cytometric monitoring of genetic damage in spermatogenic cells. The high refractive index and extreme flatness of the sperm heads produce an optical effect which interferes with DNA measurements in flow cytometers which have dye excitation and fluorescence light collection normal to the axis of flow. Orientation of sperm in flow controls this effect and results in coefficients of variation of 2.5% and 4.2%, respectively, for DNA measurements of mouse and human sperm. Alternatively, the optical effect can be used to generate shape-related information. Measurements on randomly oriented sperm from three mammalian species using a pair of fluorescence detectors indicate that large shape differences are detectable. Acriflavine-Feulgen stained sperm nuclei are significantly bleached during flow cytometric measurements at power levels routinely used in many flow cytometers. Dual beam studies of this phenomenon indicate it may be useful in detecting abnormally shaped sperm.

Animals↗