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Biomedical subjects

R Claus

Publications and source records attributed to R Claus.

At least 73 records · Page 4Linked to original sources
PubMed1989

Replenishment of AI-doses with oestrogens in physiological amounts: effect on sow prolificacy in a field trial.

Basing on results about physiological functions of seminal oestrogens in the genital tract of sows, the effects of an oestrogen replenishment to AI-doses were investigated in a field trial. Each ejaculate was split into two halves, which were either diluted to normal AI-doses (controls, n = 353) or diluted and replenished with oestrogens in physiological amounts (n = 384). Insemination by qualified technicians led to an improvement of the pregnancy rate (82.8% vs. 77.1%; p less than 0.05) and the litter size (10.8% vs. 10.3%; p less than 0.05) in favour of the oestrogen replenishment. These results partly explain the known differences in prolificacy between natural mating and AI and thus provide a basis for improvement of pig AI.

Animals↗
PubMed1989

Spontaneous electromyographic activity throughout the cycle in the sow and its change by intrauterine oestrogen infusion during oestrus.

Two experiments were carried out to monitor influences on the uterine electromyographic activity (EMG) in cyclic gilts with chronic uterine EMG electrodes. In Exp. 1 the EMG was recorded continuously from Day -1 for 24 days and was evaluated for frequency, duration and amplitude. Progesterone and oestradiol in peripheral plasma were measured daily. As high amounts of oestrogens are characteristic for boar semen, in Exp. 2 the influence of seminal oestrogens on uterine contractions at Day 0 (first day of standing reflex) was investigated in gilts with chronic intrauterine catheters. They were infused with 10 ml saline (N = 4) or saline with physiological amounts of oestrogens (5 micrograms oestradiol + 2 micrograms oestrone + 4.5 micrograms oestrone sulphate; N = 4). Sham-treated gilts (infusion catheters, no infusion; N = 5) served as controls. The EMG was recorded for 2 h before and 9 h after infusion. In Exp. 1 the maximal amplitude (2040 +/- 98 microV) and duration (32 +/- 1.7 sec) but the lowest frequency (15.8 +/- 2.1 contractions/h) were found on Day 0. With decreasing oestrogen and increasing progesterone concentrations the frequency increased continuously until Day 5 (63.5 +/- 1.0 contractions/h) while the amplitude (183 +/- 13 microV) and duration (3.3 +/- 0.7 sec) decreased. During Days 6-13 the EMG activity was not detectable. The reverse pattern was found from the onset of luteolysis until the following Day 0. On Day 0 a significant correlation between oestradiol and the duration (r = 0.81; P less than 0.01; n = 10) but not the frequency was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Reliability criteria of a bioassay using rats trained to detect estrus-specific odor in cow urine.

An odor discrimination apparatus was used to quantify the reaction of rats against odor differences of estrous and diestrous urine of cows. Rats were trained to release impulses from a microswitch when they came into contact with estrous but not diestrous urine. After training, the discrimination ability was highly significant (P< or = 0.001) between both urine types. The reaction was specific for cow urine, and no significant discrimination occurred for estrous and diestrous urine from pigs or goats, or that of women. The discrimination of urine diluted with water was still highly significant up to 1:25. Another group of rats was trained to detect camphor. Decreasing concentrations were detected down to 0.1/microg/ml when diluted in water, and down to 1/microg/ml when diluted in estrous urine. Once trained to discriminate between estrous and diestrous urine, rats maintained this ability for 12 mo. Thus, a bioassay was set up to accompany fractionation steps in the laboratory which could lead to the isolation of estrous pheromones in cow urine.

Journal Article↗
PubMed1988

Effect of hexadecane-induced vesiculation on the outer membrane of Acinetobacter calcoaceticus.

Lipopolysaccharide-rich vesicles were released from Acinetobacter calcoaceticus 69V during growth on hexadecane. Vesicle formation occurred over the whole surface of the cell as demonstrated by scanning electron microscopy. In contrast, the surface of acetate-grown cells, for which little lipopolysaccharide was found in the growth medium, appeared smooth. The overall chemical composition as well as the protein and phospholipid composition of the outer membranes of both cell types was very similar. In the vesicles all outer membrane proteins were found with the exception of an Mr 10,000 polypeptide corresponding to Braun's lipoprotein. Compared with the outer membrane, the vesicles contained more phosphatidylethanolamine. Hexadecane-grown cells were susceptible to exogenously added phospholipase. Nevertheless the barrier function towards lysozyme was retained.

Acinetobacter↗
PubMed1988

Extracorporeal shock wave lithotripsy for large renal stones. To what size is extracorporeal shock wave lithotripsy alone feasible?

The complications after extracorporeal shock wave lithotripsy (ESWL) for large renal calculi could be reduced by insertion of ureteral stents. In a prospective study, the critical stone size for ESWL combined with ureteral stenting was looked for. Sixty consecutive patients entered the study, 17 patients suffered from renal calculi with a length of greater than 4 cm and a width of greater than 3 cm (group 1), and in 43 patients the calculi measured between 4 x 3 and 2.5 x 1.5 cm2 (group 2). ESWL was performed with the Dornier apparatus HM-3. A ureteral stent was placed immediately before ESWL. In group 1 with very large stones, significantly more obstructive problems were encountered. Three months after ESWL, only 6 of 14 (43%) were free of stones or with stone material likely to discharge spontaneously. In group 2, a success rate of 25 of 29 (86%) was noticed, which was considered satisfactory. For most stones greater than 4 x 3 cm2 the combination of percutaneous nephrolithotomy and ESWL seems to be the preferred treatment.

Adult↗
PubMed1988

[A monoclonal antibody against peripheral human blood monocytes (RoMo-1)].

The monoclonal IgG2a-antibody RoMo-1 binds to peripheral human blood monocytes but does not react with other blood cells, tissue macrophages, HL-60, K 562 or U 937. It seems possible, that the antibody defines an antigen expressed on the premonocytic and monocyte stages of cells from the mononuclear phagocytic system only. The antibody is cytotoxic.

Antibodies, Monoclonal↗
PubMed1987

Seminal oestrogens in the boar: origin and functions in the sow.

The boar produces considerable amounts of oestrogens in the Leydig-cells also occurring in semen. Very high oestrogen concentrations are measurable in the fluid of the tubuli, which contribute the main part of seminal oestrogens. Additionally, the accessory sex glands add 22% of the unconjugated oestrogens and 12% of conjugated oestrogens to the ejaculate. Concentrations vary considerably according to season and individuals. So far a maximum of 15.3 micrograms was measured in one ejaculate. Infusion of oestrogens (simulation of the oestrogen content of an ejaculate) at oestrus through a catheter into the uterus lumen leads to an increase of the myometrial contraction-frequency for 3 h. Additionally "inseminations" with oestradiol-17 beta (Oe 2), oestrone (Oe 1), and oestrone-sulfate (Oe 1-S) (naturally occurring in the ejaculate) in 10-micrograms amounts at oestrus may lead to an increase of PGF2 alpha concentrations in the uterine veins within a few minutes. This increase may be found after "insemination" with each of the three steroids but not after saline. A parallel rise of the "inseminated" oestrogen is measurable in the uterine vein plasma and may reach concentrations up to several thousand pg/ml. This rise also leads to significantly increased concentrations in peripheral plasma for about 30 min after the "insemination" of Oe 2 (increase of Oe 2 and Oe 1-S) and Oe 1 (Oe 1 and Oe 1-S). Consequences of seminal oestrogens for sperm transport and the timing of ovulation are discussed.

Animals↗