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K Gärtner

Publications and source records attributed to K Gärtner.

At least 37 records · Page 2Linked to original sources
PubMed1990

Frequency distribution of body mass in groups of highly standardized laboratory rats are characterized by negative kurtosis.

8,600 laboratory rats (outbred and inbred, SPF) of 3 independent breeding and experimental units, divided into groups of in 80-100 animals of equal sex and age, were housed in groups of 5 animals of the same sex and age per cage under highly standardized (SPF) conditions. The body masses were determined monthly between 8 and 56 weeks of age. The frequency distributions of body mass per group (coefficient of variation 7-12%) very frequently showed small negative kurtosis (-0.12 to -0.76) but no general tendency to skewness. Kurtosis is small and seems to have been acquired before birth and had no genetic reasons because it was also present in groups of inbred strains and in animals not selected artificially after birth. It may be caused by shortages of both tails of the frequency distribution of the body mass.

Animals↗
PubMed1989

The influence of social rank on the susceptibility of rats to Mycoplasma arthritidis.

Social ranks (A, O, rest) of adult male inbred rats housed in groups of four per cage were determined by repeated observations of their ejaculatory patterns under competitive conditions. Once ranked, they were intravenously infected. Fifteen clinical, hematological, and serological characters were continuously observed during 110 days. Body weight reduction, arthritis score, and specific IgG antibody titers were chosen as guideline characteristics and compared between different genotypes and social rank classes. Genotypic differences account for 60-80% of the individual differences and social rank differences account for 0-40% of the individual differences within isogenic animals. Social rank affects the individual genotypes in an opposite way. Rank A males are less susceptible in genotype DA but showed increased susceptibility in genotypes AS. In genotype LEW, influence of social rank on susceptibility to Mycoplasma arthritidis could not be verified. Specific IgG antibody titers are lower in ranks showing a higher degree of susceptibility.

Animals↗
PubMed1989

DNA excision-repair ability of embryonic fibroblasts measured by UDS and thymine dimer excorporation in four inbred mice strains.

Differences in the excision-repair capability of embryonic fibroblasts of four inbred strains of mice following various degrees of UV irradiation were assessed. Two methods of determination were used: (1) the incorporation of 3H-thymidine during unscheduled DNA synthesis (UDS) as measured by an autoradiographic technique; (2) the rate of excision of thymine dimers (TT) in the acid-insoluble fraction of the cellular DNA as determined by a dimerspecific radioimmuno-assay. Based on UDS, the repair rates of the four strains could be ranked in decreasing order as follows: DBA/2 (DB); C57BL/6J (B6); AKR/N (AK); CBA/J (CB). The calculated rate for DBA/2 (DB) is approximately twice that of CBA/J (CB). The determination of the TT excision rate indicates that 72 h after irradiation a maximum of 50% of the original UV-induced dimers in the DB strain could be repaired. In the three remaining strains the relatively reduced repair rates of 15% - 40% did not differ significantly.

Animals↗
PubMed1988

Paternal influence on timing of pronuclear DNA synthesis in naturally ovulated and fertilized mouse eggs.

Fertilized oocytes of the inbred genotypes AKR (AK), C57BL/6 (B6), DBA/2 (D2), and CBA (CB) and the hybrid genotypes F1 (female AK X male B6) and F1 (female B6 X male AK) were collected by flushing the oviducts of female mice every 2 h from 2 until 26 h post coitum. Developmental stages of the embryos and DNA content of the pronuclei were estimated by morphological criteria and cytofluorometric measurement of the pronuclei (ethidium bromide-stained DNA), respectively. In all genotypes, S-phase started about 4 h post conception (h.p.c.). The duration of S-phase amounted to 5.9 h (F1 [female B6 X male AK]), 6.4 h (AK), 8.5 h (B6), 9.4 h (F1 [female AK X male B6]), 9.8 h (D2), and 11.4 h (CB). In each of the reciprocal F1 hybrids, the length of S-phase differed from the maternal genotype (p less than 0.01) and resembled closely the paternal genotype (p greater than 0.25). Cleavage from one-cell stage to two-cell stage occurred between 16 and 21 h.p.c.

Animals↗
PubMed1986

100 years of animal welfare regulation and of experiments with animals in Germany, effects and reasons.

The first regulations (1883) have been renewed twice (1933, 1972) and will soon be renewed once again (1986). They have always been influenced by two motivations: men's feeling of responsibility for animals on one hand and antiscientism or public suspicion against scientists on the other hand. The general rules concerning animal welfare (anaesthesia, reduction of number and harm, species selection etc.) have been constant for 100 years, but governmental control increases by the establishment of special licences (for each project, for the responsible scientist, for the location) by regular controls of the laboratories, by installing a permanent animal welfare officer in the institutions, by protocols, special taxes and increasing penalties. Out of different public ethical concepts about the use of animals, the law for the present agrees with those permitting to use animals for "reasonable purposes". But now the public opinion wants to change to "only for necessary" purposes; this especially concerns animal experiments causing severe pain. Philosophers and public have difficulties to find consentaneous reasons for the "necessity" of basic research. Each basic research in biology must be accepted as necessary because life is multifactorially organized and can be analyzed sufficiently only by random-like strategies to test not monocausally evidenthypotheses alone, but all reasonable possibilities.

Animal Welfare↗
PubMed1984

Monozygotic vs. dizygotic twin behavior in artificial mouse twins.

Adult inbred mice of an isogenic strain (AKR/NHan or C57BL/6J Han) differ in social (sexual and agonistic), emotional and psychomotoric behavior, depending on the kind of manipulation to which they were subjected at an early ontogenetic stage. Monozygotic twins (MZT) from eight-cell stages halved and transferred to uterine foster mothers were compared with dizygotic twins (DZT) from nonreduced but transferred eight-cell stages and with naturally born animals (NBA). Generally, early embryonic conditions predict the behavioral characteristics of the adult animals to a high degree. The MZT are motorially less active, less emotional, less aggressive and less socially interested than DZT and NBA. In tests of spontaneous social behavior (allogrooming, anogenital licking, mounting, fighting), as well as in tests for emotionality (open field: crossed fields and defecation), these behavioral patterns occurred less frequently in MZT than in DZT; the NBA were mostly intermediate. The copulatory pattern of male MZT differs from that of male DZT by a shortage of intromission latency and duration; furthermore, MZT pairs do not build up a steady rank order in competitive copulation tests, as opposed to DZT and NBA pairs. In a test for psychomotoric behavior (swimming), the MZT prefer "floating" as a survival strategy, whereas the DZT and NBA prefer "adult swimming." Therefore, it can be concluded that these behavioral differences may be caused by the particular psychosocial environment in which the twins grow up or may be due to early prenatal peculiarities, such as inadequate synchronization of the developmental status of uterus and embryo.

Animals↗
PubMed1983

Distribution of glomeruli in the renal cortex of Munich Wistar Frömter (MWF) rats.

The glomerular distribution in the renal cortex of the Munich Wistar Frömter (MWF) rat, a substrain of the Munich Wistar rat selected for superficial glomeruli, was compared to that of a control strain (LEW/Ztm) between 10 and 150 days of age. While there were no significant differences in body growth, kidney weight, or growth of the renal cortex in these two strains, the average diameter of Bowman's capsule and of the glomerular tuft was significantly larger (about 12%) in rats of the MWF strain which were older than 60 days. In histological sections of kidneys of MWF rats in all age groups, many glomeruli in direct contact with the renal capsule were found; thus, this developmental step must have taken place before 10 days of age. The appearance of superficial glomeruli was due to a shift of glomeruli to a position just under the renal surface, the subcapsular zone or 'cortex corticis', which is normally free of glomeruli. For the rest of the renal cortex there were only slight differences in glomerular density and in total number of glomeruli per section between these two strains. These results lead us to suppose that superficial glomeruli belong to a special nephron type; thus, these glomeruli are not enveloped by parts of the proximal tubule.

Animals↗
PubMed1982

Intraspecies allometry: correlation between kidney weight and glomerular filtration rate vs. body weight.

Allometric equations of the form of Y = a*BWb were calculated between body weight (BW) on the one hand and either kidney weight (KW) or glomerular filtration rate (GFR) on the other. By using strain and sex means obtained from 24 different inbred strains of adult mice or F1-hybrids environmental and genetical influences could be separated statistically. Thus, allometric equations reported in this study describe exclusively genetic influence. The parameters for intraspecies allometric equations obtained in these studies were compared to those in the literature presenting interspecies relationships. The double logarithmic regressions of KW vs. BW gave results different from the interspecies equation. The difference between intra- and interspecies results of allometric relationships may be due to the experimental exclusion of environmental influences. The regression parameters for GFR vs. BW obtained for the inbred strains, however, agreed very well with those of the empirical equation for interspecies relationship and also with the theoretically expected value. The dependence of GFR on BW was found to be GFR = 0.036*BW0.74 +/- 0.15, where GFR is measured in ml/min and BW in g. The exponent of 0.74 seems to be a valid biological constant that is genetically determined within and across species lines.

Animals↗
PubMed1982

The renal clearance of albumin following intravenous loading of homologous albumin in conscious rats.

Tubular reabsorption of albumin was studied in conscious rats by measuring the renal excretion at various plasma concentrations. The plasma albumin concentration was raised by loading the animals with homologous serum albumin. By using this procedure an average plasma concentration of 54 g/l could be reached, which is about twice the physiological plasma albumin concentration in untreated rats. Throughout the experiments the glomerular filtration rate was determined by the total plasma slope clearance of 51Cr-EDTA. Following the albumin load, the 51Cr-EDTA clearance remained at 54.8 +/- 12.2 ml/min/m2 body surface. By correlating renal albumin excretion and plasma albumin concentration, the sieving coefficient of albumin, phi, of 2.35 x 10(-4), the renal albumin threshold of 38 +/- 5 g/l, and the maximal tubular transport rate of albumin of 9.6 +/- 2.6 micrograms/min/g kidney weight could be calculated (mean +/- SD). There were some variations among the animals, resulting in a fairly large standard deviation. However, these values are in agreement with recent micropuncture data.

Animals↗
PubMed1982

Post-mating non-infectious hydrometra in BALB/c: Bom mice.

Post-mating non-infectious hydrometra and hydrovagina of unknown aetiology, leading to a scrotum-like swelling of the perineum, was observed during an experiment on BALB/c: Bom mice. There was a closure of the vulva with accumulation of secretions of uterine glands under high pressure in both uterus and vagina. The mice were otherwise clinically healthy, gained body weight normally, but were incapable of breeding. The morbidity was approximately 1% and the disease could not be transmitted to other females.

Animals↗