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Biomedical subjects

K Meyer

Publications and source records attributed to K Meyer.

At least 181 records · Page 10Linked to original sources
PubMed1994

Cardiopulmonary exercise capacity in healthy normals of different age.

Sixty-nine healthy normals from the 3rd to the 6th decade were stressed to exhaustion by means of a cardiopulmonary exercise test on a bicycle ergometer. Peak VO2, VCO2 and ventilation differed significantly between the four decades: peak VO2 (mean +/- SD) was 3,393 +/- 516; 3,061 +/- 444; 2,817 +/- 801 and 2,589 +/- 687 ml/min (p < 0.001). The mean value for respiratory gas exchange ratio (R) at ventilatory threshold (VT) was 0.86 and for ventilatory equivalent O2 (EqO2) 0.24. Mean VO2 at VT was 1,662 +/- 521; 1,462 +/- 308; 1,474 +/- 559 and 1,268 +/- 232 ml/min (p < 0.05). The VO2 of the four age groups at VT was between 47 and 49% of peak VO2 (n.s.), and both parameters correlated significantly (r = 0.67, p < 0.001). The average increase of VO2 in relation to work rate (ml/W/min) was 11.5 +/- 1.2 for the total exercise and was below VT lower (9.4 +/- 1.9) than above VT (12.9 +/- 1.2) (p < 0.001).

Adult↗
PubMed1994

Genetic parameters for milk production of Australian beef cows and weaning weight of their calves.

Estimates of covariance components were obtained for milk production of beef cows, measured by the weigh-suckle-weigh method, and weaning weight and preweaning growth of their calves for a herd of Polled Herefords and a herd of a multibreed synthetics, so-called Wokalups. Analyses were carried out by restricted maximum likelihood fitting an animal model incorporating both direct and maternal genetic and permanent environmental effects and allowing for the direct-maternal covariances. Average 14-h milk yield was 3.6 kg for Herefords and 4.9 kg for Wokalups and heritabilities were .12 and .08, respectively. Treating preweaning gain of the calf as a trait of the cow, estimates of the additive genetic and permanent environmental correlations between preweaning gain and milk yield were higher for Herefords (.73 and 1.00, respectively) than for Wokalups (.53 and .77). Bivariate analyses of milk production (treated as a trait of the cow) and weaning weight (treated as a trait of the calf) showed virtually no direct additive genetic, direct permanent environmental, or phenotypic association between the two traits but identified strong correlations between direct effects for milk yield and maternal effects for weaning weight. The estimate of the direct-maternal genetic correlation between milk yield and weaning weight was .80 for both breeds, and the estimated correlation between direct, permanent environmental effects for milk yield and maternal, permanent environmental effects on weaning weight was unity for Herefords and .89 for Wokalups. Results indicate that milk production is the main determinant of maternal effects on the growth of beef calves with breed differences in the importance of maternal effects largely attributable to differences in milk production.

Analysis of Variance↗
PubMed1994

Antisense inhibition of myeloperoxidase increases the sensitivity of the HL-60 cell line to vincristine.

Myeloperoxidase (MPO), a heme-peroxidase found in the HL-60 myeloblastic cell line, is involved in vincristine (VCR) metabolism and the inactivation of this drug. We have examined whether decreased MPO activity correlated with increased sensitivity to VCR toxicity in myeloid leukemia cells. We have used MPO antisense RNA to reduce 60% of the MPO activity in the HL-60 cells. The MPO-deficient HL-60 cell line, C15, was significantly more sensitive to VCR than the parental MPO-positive cell line. Both cell lines were negative for P170-glycoprotein expression. Conversely, an MPO-positive C15 subclone was more resistant to VCR than the MPO-deficient C15 cell line. No significant differences in cytotoxic effects were observed between MPO-positive and MPO-deficient cells, following treatment with either daunorubicin or actinomycin D, two multidrug resistance-related drugs. These results strongly support an important role for MPO in VCR resistance in HL-60 cells. Antisense manipulation of the MPO content of myeloid cells could be of potential interest in leukemia treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Genetic parameters for growth traits of Australian beef cattle from a multibreed selection experiment.

Estimates of covariance components and genetic parameters were obtained for birth, weaning, 200-d, and 400-d weight for a herd of Polled Herefords and a herd of a multibreed synthetics, the so-called Wokalups. Data originated from an experiment in Western Australia selecting for preweaning growth rate. Analyses were carried out by REML fitting an animal model including genetic and permanent environmental maternal effects. Wokalups showed consistently more phenotypic variation, partly due to a scale effect, and higher direct and lower maternal heritabilities than Herefords. Maternal environmental effects were more than twice as important in Herefords than in Wokalups. Estimates of both genetic and environmental correlations among weaning and subsequent weights were essentially unity, identifying maternal effects found for postweaning weights as a "carry over" of those on weaning weight.

Analysis of Variance↗
PubMed1993

Biodistribution, metabolism, and excretion of radioiodinated phospholipid ether analogs in tumor-bearing rats.

The phospholipid ether analog, [125I]-1-O-[12-(m-iodophenyl)dodecyl]propanediol-3-phosphocholine (NM-295) was synthesized and evaluated for its ability to visualize tumors. Preliminary studies were performed in rats bearing the Walker 256 carcinosarcoma. Most of the radioactivity was cleared from the animals during the first 24 hours. However, the tumor showed a decreased rate of clearance of radioactivity when compared with non-target tissue. This difference in the clearance rate allowed for excellent images of the tumor at 24 hours. Scintigraphic images compared favorably with other radioiodinated phospholipid ether analogs such as [125I-rac-1-O-[12-(m-iodophenyl)dodecyl]-2-O-methylglycero-3- phosphocholine (NM-294) and [125I]-12-(m-iodophenyl)dodecyl phosphocholine (NM-324). In contrast with the latter two compounds, however, tissue distribution studies revealed that NM-295 cleared at a much faster rate from all tissues, including tumor. In addition, within 24 hours following administration of NM-295, over 70% of the radioactivity was excreted as compared to 50% and 20% for NM-294 and NM-324, respectively. The majority of excreted radioactivity appeared in the urine for all three compounds. Thin-layer chromatography of urine and fecal extracts showed the presence of metabolites only. In contrast, lipid extracts of either liver or tumor demonstrated only the presence of the parent compound. Therefore, these data suggest that in each case it was the parent phospholipid analog that was taken up and retained by the tissues, while the metabolic product(s) was cleared and excreted from the animal.

Animals↗
PubMed1993

Human ehrlichiosis in Florida.

Human ehrlichiosis has been relatively recently identified in the United States. We report a case of human ehrlichiosis recently diagnosed in Jacksonville. A high index of suspicion in an appropriate clinical setting is needed to make this diagnosis. This disease is most often confirmed by serologic tests. Patients benefit from antimicrobial therapy.

Animals↗
PubMed1993

Photopheresis for ARC: a nursing perspective.

Photopheresis, an approved treatment for cutaneous T-cell lymphoma (CTCL), is the basis of a trial involving patients with AIDS-related complex (ARC). This study has provided the opportunity to identify unique nursing challenges along with satisfaction from innovative nursing interventions.

AIDS-Related Complex↗
PubMed1993

[Spontaneous rupture of the urinary bladder after radiotherapy].

The spontaneous intraperitoneal rupture of the urinary bladder is an extremely rare life threatening event. There are often difficulties in making the diagnosis. A case of spontaneous rupture of the bladder 6 years after radiation therapy for uterus cancer is reported. An early surgical exploration including the closing of the rupture, peritoneal lavage and continuous vesical drainage will save the life of the patient.

Combined Modality Therapy↗
PubMed1992

Outpatient protocol for biofeedback therapy of pelvic floor outlet obstruction.

Pelvic floor outlet obstruction is a rare cause of severe constipation. Anal myectomy, subtotal colectomy, and medical therapy have limited success. The purpose of this study was to develop a short outpatient treatment using biofeedback techniques. Nine patients with severe constipation and straining resulting from pelvic floor outlet obstruction underwent complete investigation of the pelvic floor musculature and anal sphincter mechanism. Patients were unable to expel a 60-cc rectal balloon and had nonrelaxing puborectalis on defecography. The treatment protocol utilized anal surface electromyography to document improper straining and retrain pelvic floor muscles to relax during defecation. Sensory retraining with a rectal balloon, behavioral relaxation techniques, and defecation of simulated stool using a 120-cc Metamucil (Procter & Gamble, Cincinnati, OH) slurry in the rectum allowed re-establishment of normal defecation in all nine patients. Repeat training was required in three patients during follow-up. Treatment of pelvic floor outlet obstruction with outpatient retraining techniques is possible.

Adult↗
PubMed1992

Mouse erythrocyte rosette formation with malignant human B-lymphocytes re-evaluated: still a useful marker for differentiating mature B-cell malignancies.

We have re-evaluated mouse rosette formation (MRF) as a marker for B-CLL by estimating the fraction of mouse rosette forming B-lymphocytes (identified by CD20 monoclonal antibodies) in normal donors and malignant CD20+ cell proliferations (ALL, AML, B-NHL, B-HCL and B-CLL). Whereas this ratio was increased in B-CLL, all other CD20 positive malignancies showed mean ratios of less than 0.1. As part of a Danish multi-centre study, we furthermore prospectively analysed 86 patients and found that the mouse/CD20 ratio divided the 78 patients with monoclonal B-cell populations suspected of B-CLL in two distinct groups. In the low ratio group, three patients were categorized as leukaemized B-NHL and one as PLL. The remaining three patients with low ratio were clinically and immunologically (by SmIg density and CD5 expression) B-CLL patients suggesting a frequency of MR-negative B-CLLs of approximately 5%. In the high ratio group two of 70 patients were diagnosed as B-NHLs. Thirdly, MRF was a valuable parameter in patients, where transformation of disease is suspected, since it preceded clinical changes by several months. Thus, MRF is still a useful marker in the age of monoclonal antibodies.

Adult↗
PubMed1992

Sire x herd interactions for weaning weight in beef cattle.

Weaning weight records of 44,357 Australian Angus calves produced by 1,020 sires in 90 herds were used to evaluate the importance of sire x herd interactions. Models fitted fixed effects of contemporary group (herd-year-date of weighing subclass), sex, calf age, and dam age and random effects of sire or of sire and sire x herd interaction using REML. Effects of standardizing the data, including sire relationships and including dam maternal breeding values (MBV) as a covariate were also investigated. Sire x herd interactions were found (P less than .05) in all cases and, in the most complete model, accounted for 3.3% of phenotypic variance. Across-herd heritabilities ranged from .19 to .28. Differential nonrandom mating among herds seemed to occur in the data. Significant sire x herd effects were observed for dam MBV, and adjustment for dam MBV yielded the smallest estimates of interaction variance and across-herd heritability. If sire x herd interactions were due only to genotype x environment interaction, within-herd heritabilities would range from .33 to .49. These estimates are larger than previously reported estimates. Thus, unreported environmental effects common to progeny of individual sires may also be involved in the observed interaction but could not be disentangled from true genotype x environment interaction effects using these data. Results of these analyses suggest that some accommodation of sire x herd interaction effects on weaning weight may be needed in beef cattle genetic evaluations, but a compelling case for development of herd-specific breeding value prediction cannot be made.

Animals↗
PubMed1992

[Interval resistance exercise in comparison with bicycle ergometry stress. Studies with resistance endurance training in coronary patients].

UNLABELLED: In the rehabilitation of coronary patients there is an increased interest in using complementary resistance exercise training. Therefore, we studied nine patients (males; age: 51 +/- 7 years) with chronic stable coronary heart disease during extensive resistance exercise (ex RE) (legpress, abduction, adduction) (60-s work: 60-s rest; contraction intensity: 65% of 1 RM) and during intensive resistance exercise (int. RE) (legpress) (30-s work: 45-s rest) with 85% of 1 RM. Non-invasive continuously measured blood pressure, heart rate, norepinephrine, epinephrine, lactic acid, and glucose were compared with values from maximal bicycle ergometry (3-min steps, each 25 w; max. performance: mean 156 w; range 125-200 w). RESULTS: 1) Comparing ex RE and int RE with bicycle ergometry there were no differences in blood pressure (systolic: 206 and 204 vs. 210 mm Hg; ns; diastolic: 98 and 104 vs. 92 mm Hg; ns). Heart rates (104 and 103 vs. 125/min; p < .01), norepinephrine (3.8 and 3.3 vs. 8.8 nmol/l; p < .01) and epinephrine (0.7 and 0.6 vs. 1.4 nmol/l; p < .01) were considerably lower. 2) The most significant increase and decrease of blood pressure and heart rate occurred within 15-30 s after the beginning and end, respectively, of isometric exercise. CONCLUSIONS: 1) ex RE is suitable for patients with stable CHD and cardiac exercise tolerances of 1.5-2 W/kg = 125-150 watts. 2) Blood pressure monitoring by the cuff method (RR) immediately after RE did not reflect blood pressure during RE. 3) Controlling RE by the training heart rate prescribed for endurance exercise is not possible.

Adult↗