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Biomedical subjects

R Wolter

Publications and source records attributed to R Wolter.

At least 19 recordsLinked to original sources
PubMed2005

A procedure to define natural groundwater conditions of groundwater bodies in Germany.

Commissioned by Germany's Working Group of the Federal States on Water Problems (LAWA) the authors developed a procedure to define natural groundwater conditions from groundwater monitoring data. The distribution pattern of a specific groundwater parameter observed by a number of groundwater monitoring stations within a petrographically comparable groundwater typology is reproduced by two statistical distribution functions, representing the "natural" and "influenced" components. The range of natural groundwater concentrations is characterized by confidence intervals of the distribution function of the natural component. The applicability of the approach was established for four hydrochemically different groundwater typologies occurring throughout Germany. Based on groundwater monitoring data from 7920 groundwater monitoring stations, 15 different hydrochemical parameters were evaluated for each groundwater typology. For all investigated parameters the range of natural groundwater concentrations has been identified. According to the requirements of the EC Water Framework Directive (article 17) (WFD) this study is a basis for the German position to propose criteria for assessing a reference state for a "good groundwater chemical status".

Environmental Monitoring↗
PubMed1999

Mapping of cytoskeletal components in the hippocampal formation of the tree shrew (Tupaia belangeri).

The distribution of the major cytoskeletal components in frontal cryosections of the hippocampal formation of adult male tree shrews (Tupaia belangeri) was immunohistochemically investigated by using commercially available antibodies. Actin-immunolabeling was evident in all layers of the dentate gyrus as well as in the regio superior (CA1) and the regio inferior (CA3). Neurofilament 160 was detected only in the molecular layer of the dentate gyrus and in the axons of the granule cells (mossy fibers). For beta-tubulin, the microtubule associated proteins (MAPs) MAP2AB, MAP2ABC and Tau, immunoreactivity was evident within the granule cells and within the somatodendritic compartment of pyramidal neurons. Granule cells and the somata of the pyramidal neurons were intensely labeled for kinesin. Our findings show the elaborate expression of cytoskeletal proteins in the hippocampal formation of the tree shrew, relatively similar to what is seen in other species but with also some important differences, such as the immunonegativity of the axonal compartment for Tau in the tree shrew, which is contrary to what we see in the mouse (unpublished data). These findings provide useful insights regarding the organization of the hippocampal formation of the tree shrew and are fundamental for further research in this field.

Actins↗
PubMed1996

Regulation of SNM1, an inducible Saccharomyces cerevisiae gene required for repair of DNA cross-links.

The interstrand cross-link repair gene SNM1 of Saccharomyces cerevisiae was examined for regulation in response to DNA-damaging agents. Induction of SNM1-lacZ fusions was detected in response to nitrogen mustard, cis-platinum (II) diamine dichloride, UV light, and 8-methoxypsoralen + UVA, but not after heat-shock treatment or incubation with 2-dimethylaminoethylchloride, methylmethane sulfonate or 4-nitroquinoline-N-oxide. The promoter of SNM1 contains a 15 bp motif, which shows homology to the DRE2 box of the RAD2 promoter. Similar motifs have been found in promoter regions of other damage-inducible DNA repair genes. Deletion of this motif results in loss of inducibility of SNM1. Also, a putative negative upstream regulation sequence was found to be responsible for repression of constitutive transcription of SNM1. Surprisingly, no inducibility of SNM1 was found after treatment with DNA-damaging agents in strains without an intact DUN1 gene, while regulation seems unchanged in sad1 mutants.

Antineoplastic Agents↗
PubMed1995

Sequence analysis of a 5.6 kb fragment of chromosome II from Saccharomyces cerevisiae reveals two new open reading frames next to CDC28.

The sequence of a 5653 bp DNA fragment of the right arm of chromosome II of Saccharomyces cerevisiae contains two unknown open reading frames (YBR1212 and YBR1213) next to gene CDC28. Gene disruption reveals both putative genes as non-essential. ORF YBR1212 encodes a predicted protein with 71% similarity and 65% identity (total polypeptide of 376 aa) with the 378 aa Surl protein of S. cerevisiae, while the putative product of ORF YBR1213, which is strongly expressed, has 28% identity with a Lactococcus lactis-secreted 45 kDa protein and 24% identity with the Saccharomyces cerevisiae AGA1 gene product.

Amino Acid Sequence↗
PubMed1993

Determination of the optimal treadmill slope for reproducing the same cardiac response in saddle horses as overground exercise conditions.

The purpose of this study was to define the most suitable treadmill slope for reproducing the same heart rate response as in horses being ridden on a track. Seven French saddle horses were exercised first on a level turf track and then on a treadmill. On the track the exercise test consisted of four periods of three minutes of increasing speeds at the trot and the gallop (96 to 600 m/minute). The treadmill exercise tests consisted of seven steps of increasing slope (0 to 9.6 per cent) at the trot (252 m/minute), followed, after an active recovery period at the walk with a 0 per cent slope, by five steps of increasing slope for two minutes each (0 to 6.3 per cent), at the gallop at 493 m/minute. The mean heart rate at each step of the exercise tests was measured with a heart rate recorder. On the exercise track there was a strong linear relationship (R = 0.89, P < 0.01) between heart rate and speed. The heart rate response of the horses exercised at different speeds and slopes on the treadmill was best fitted (R = 0.96, P < 0.01) by a multilinear model. The optimal treadmill slope was determined by equalizing the equations derived from the two tests: s = -0.001 V + 3.658. It was concluded that the optimal treadmill slope ranged between 3.0 and 3.7 per cent. In order to verify this result, a comparison was made between the heart rate response of the horses during the same incremental exercise test performed on the track and on the treadmill with a 3.5 per cent slope.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Stride characteristics of overground versus treadmill locomotion in the saddle horse.

The purpose of this study was to compare the velocity-dependent changes in stride length and stride frequency of horses performing the same incremental exercise test first on a track with a rider and then on a treadmill with a 0 and 3.5% slope successively. Seven French saddle horses undertook the exercise test which consisted of 5 stages of increasing speed for 3 min each with 1 min rest between each stage (1.6, 4.2, 8.3, 9.2 and 10 m/s). The horses were recorded by use of a video camera, and the tapes were analysed with regard to gait parameters. At 1.6, 8.3, 9.2 and 10 m/s, stride frequencies were significantly (p < 0.01) greater on the track than on the treadmill. At the walk, stride length was significantly (p < 0.01) shorter on the track than on the treadmill. There were strong linear relationships between stride length and speed in all experimental conditions (R2 > 0.96). The comparison of the regression coefficients revealed significant differences (p < 0.01) between track and treadmill locomotion; stride length was longer on both the horizontal and inclined treadmill than on the track. The incline of the treadmill did not significantly (p > 0.01) influence stride parameters.

Animals↗
PubMed1992

Proper ventilation improves indoor air quality.

Buildings constructed in the 1970s often achieved energy efficiency at the cost of adequate fresh air, leading to unhealthy working conditions. Through a program of preventive maintenance, inspections and attention to employee concerns, most indoor air-quality problems can be avoided.

Air Pollution, Indoor↗
PubMed1990

Trichothiodystrophy, mental retardation, short stature, ataxia, and gonadal dysfunction in three Moroccan siblings.

Three sibs, a boy and two girls, born to Moroccan consanguineous parents, were affected with a syndrome characterized by brittle hair, mental retardation, short stature, ataxia, and gonadal dysfunction. The hair in these three patients displayed the morphological and biochemical hallmarks of trichothiodystrophy (TTD). Gonadal function tests showed abnormal gonadotropic responses to LHRH, consistent with delayed puberty in the male and ovarian failure in both females. Comparison with previously reported cases of TTD associated with mental retardation suggests genetic heterogeneity, although specific biochemical markers are needed in order to answer this question.

Abnormalities, Multiple↗
PubMed1989

Serum gonadotropins levels in childhood. Critical comparison between immunoradiometric assays and radioimmunoassays.

The complex changes in serum LH and FSH levels from infancy to adulthood are diversely evaluated by radioimmunoassays or bioassays. The relative lack of sensitivity and specificity of radioimmunoassay, using polyclonal antibodies, could possibly be overcome by new immunoradiometric assays, using specific antibodies to LH and FSH. Significant differences were indeed observed between radioimmunoassays and immunoradiometric assays. during the prepubertal period, LH levels, measured by the immunoradiometric assays, were below the sensitivity of the method in the majority of the samples. LH levels were, however, well detectable when measured with radioimmunoassay, showing the heterogeneity of circulating LH structures. At the onset of puberty, LH levels increased at least 3 to 4 times in both sexes, when measured with immunoradiometric assays, whereas their increase was only 20 to 60% with the radioimmunoassays. FSH levels remained well detectable able in the prepubertal period whether measured by immunoradiometric or radioimmunoassays. At pubertal onset, FSH increase in both sexes was more important in the immunoradiometric assays. The results obtained with immunoradiometric assays give a better insight into the quantitative and qualitative function of the gonadotropes during childhood. The almost complete absence of LH during the prepubertal period and the steep increase at the onset of puberty better reflects the reported data obtained with bioassays. The persistence of significant levels of FSH in the prepubertal ages, and the lesser increase at the onset of puberty, when compared with LH, illustrates that the individual regulation of LH and FSH secretion vary over time and is influenced by developmental factors.

Adolescent↗
PubMed1989

[The effect of delayed medical consultation on the results of ergotherapy].

In connection with 567 patients suffering from finger and metacarpale fractures who were treated conservatively the influence of the delaying time on the ergotherapy with its consequences was investigated, but also the influence of the ergotherapy itself. 80.3% of the patients showed a complete rehabilitation after an immediate beginning of ergotherapy. Only 41.0% of the patients remained without residual defects with the beginning of the ergotherapy after a conservative immobilisation therapy. Similar insufficient results were obtained in the group without ergotherapy (only 51.1%). Though after some years the function at late injuries was improved by the help of training in daily life and by means of work remarkable differences between the ergotherapy group and the collective without ergotherapy are recognizable.

Disability Evaluation↗
PubMed1987

Early initiation of growth hormone treatment: influence on final height.

Retrospective growth data for 34 hGH deficient patients who had been treated for at least 3 years with hGH were analysed in a Belgian multicentre study. Final height was related to target height and was usually below it, but it was not determined by chronological or bone ages, bone age delay, height velocity before or during therapy, nor by duration of treatment. Total height gain during long-term substitution with hGH is inversely related to chronological and bone ages at the start of therapy, and is positively related to the duration of therapy. Early diagnosis of hGH deficiency is thus important, as it allows catch-up growth to optimal height before puberty, which in turn results in a good pubertal growth spurt.

Adolescent↗
PubMed1987

[Establishment of a re-entrant ileo-cecal fistula in Equidae].

A re-entrant cannulation of the digestive tract was performed in Equidae (ponies and donkeys) between the distal extremity of the ileum and the base of the caecum. The operative technique was conceived to avoid risks of infection of the peritoneal cavity: the openings of the ileum and of the caecum were achieved only after the closure of the abdominal wall incision. Two donkeys were still alive ten months after the operation. This method can provide a convenient model for digestibility studies in Equidae, particularly for assessment of the pre-caecal digestibility.

Animals↗
PubMed1986

Pubertal growth and final height in hypopituitary boys: a minor role of bone age at onset of puberty.

Twenty-two hypopituitary boys treated with human GH were studied longitudinally before and during puberty. Eight patients entered spontaneous puberty at a mean bone age of 12.4 +/- 1.0 (+/- SD) yr. Height velocity reached a mean peak of 6.8 cm/yr during the second year of spontaneous puberty. In these patients, the mean total height gain throughout puberty was 22.8 +/- 5.2 cm, and the mean final height was 158.6 +/- 7.2 cm. Fourteen patients received testosterone enanthate (100 mg/month, im) starting at a mean bone age of 13.6 +/- 1.1 yr. Height velocity was maximal (7.5 cm/yr) during the first year of therapy. The mean final height was 162.9 +/- 5.0 cm, with a mean pubertal gain of 15.9 +/- 3.8 cm. Genital development, peak height velocity, and increase in plasma testosterone levels occurred earlier during testosterone therapy than during spontaneous puberty. In both groups of patients, there was a positive correlation between the bone age at onset of puberty and the height at onset of puberty (r = 0.65). There was also a negative correlation between bone age and total pubertal height gain (r = -0.73). This reduction in pubertal height increase was less than expected for bone age at onset of puberty, which can be explained by a decrease in bone age velocity in relation to bone age at onset of puberty (r = -0.81). Therefore, advancement in bone age at the onset of testosterone therapy did not impair final height, whereas it may increase height at onset of puberty, which is the major factor in final height. We conclude that in GH- and gonadotropin-deficient boys 1) a reduced dosage of testosterone enanthate (25 mg twice a month, im) should be used to induce pubertal development, and 2) the major criterion to decide when to give testosterone is height reached at that time regardless of bone age.

Adolescent↗
PubMed1986

Generalized unresponsiveness to mineralocorticoid hormones: familial recessive pseudohypoaldosteronism due to aldosterone-receptor deficiency.

The present report describes two sibs--born from consanguineous parents--presenting with severe salt wasting. Generalized pseudohypoaldosteronism (PHA) was diagnosed on the basis of markedly elevated sodium concentration in urine (84 & 63 mmol/L respectively), sweat (181 & 196), saliva (- & 120) and stool (- & 189), hyponatremia (112 & 132) and hyperkalemia (10.7 & 7.3) in the presence of increased plasma aldosterone (greater than 8.5 & 5.4 ng/ml), plasma renin activity (40 & 18.9 ng/ml/hr) and urinary aldosterone (greater than 32 & 11.6 micrograms/day). Both parents investigated under basal conditions (sodium ad libitum) and under sodium restricted diet appeared to be normal. Aldosterone binding studies performed on mononuclear leukocytes showed no type I receptors in the investigated child whereas low amounts were found in both parents (90 sites/cell and 63 sites/cell in the mother and the father, respectively). Isolated renal unresponsiveness to mineralocorticoid hormones is thought to be an autosomal dominant inherited disease. In contrast, the results obtained in these two new cases of generalized PHA, as well as the fact that four of five yet reported cases were born from consanguineous parents, suggest an autosomal recessive mode of inheritance for generalized PHA.

Aldosterone↗
PubMed1986

Evidence against growth hormone-releasing factor deficiency in children with idiopathic obesity.

The mechanisms whereby growth hormone (GH) secretion is decreased in human obesity remain obscure. We studied the response of plasma GH and prolactin (PRL) to an I.V. dose of 0.5 mcg/kg of growth hormone releasing factor (GRF) in three groups of children: lean (N = 12), obese (N = 15) and GRF-deficient, i.e. children with complete GH deficiency on the basis of conventional provocative testing and evidence of hypothalamic dysfunction on the basis of thyrotropin-releasing hormone testing (N = 7). Mean (+/- SEM) peak plasma GH after GRF was blunted to the same extent in obese and in GRF deficient children (11.1 +/- 2.2 and 8.3 +/- 2.8 ng/ml) as compared to lean control children (34.7 +/- 4.7 ng/ml). The pattern of PRL response to GRF was however different in GRF deficient children, whose high basal PRL levels increased further after GRF injection, and in obese and lean children, who had n alpha acute change in PRL levels after GRF. Baseline plasma somatomedin C concentrations were low for age in GRF deficient children and tended to be high for age in obese children. On the basis of these discrepant patterns of response of PRL to GRF and plasma somatomedin C concentrations, we conclude that GRF deficiency does not account for the decreased GH secretion observed in obese children.

Adolescent↗
PubMed1985

Effect of growth hormone-releasing factor on plasma growth hormone, prolactin and somatomedin C in hypopituitary and short normal children.

We studied the effect of a single intravenous bolus of 0.5 microgram/kg of growth hormone-releasing factor (GRF) on plasma GH, prolactin (PRL) and somatomedin C (SMC) in 12 short normal children and 24 patients with severe GH deficiency (GHD), i.e. GH less than 5 ng/ml after insulin and glucagon tolerance tests. GRF elicited an increase in plasma GH in both short normal and GHD children. The mean GH peak was lower in the GHD than in the short normal children (8.2 +/- 2.5 vs. 39.2 +/- 5.1 ng/ml, p less than 0.001). In the GHD patients (but not in the short normals) there was a negative correlation between bone age and peak GH after GRF (r = -0.58, p less than 0.005); GH peaks within the normal range were seen in 5 out of 8 GHD children with a bone age less than 5 years. In the short normal children, GRF had no effect on plasma PRL, which decreased continuously between 8.30 and 11 a.m. (from 206 +/- 22 to 86 +/- 10 microU/ml, p less than 0.005), a reflection of its circadian rhythm. In the majority of the GHD patients, PRL levels were higher than in the short normal children but had the same circadian rhythm, except that a slight increase in PRL was observed 15 min after GRF; this increase in PRL was seen both in children with isolated GHD and in those with multiple hormone deficiencies; it did occur in some GHD patients who had no GH response to GRF. Serum SMC did not change 24 h after GRF in the short normal children. We conclude that: (1) in short normal children: (a) the mean GH response to a single intravenous bolus of 0.5 microgram/kg of GRF is similar to that reported in young adults and (b) GRF has no effect on PRL secretion; (2) in GHD patients: (a) normal GH responses to GRF are seen in patients with a bone age less than 5 years and establish the integrity of the somatotrophs in those cases; (b) the GH responsiveness to GRF decreases with age, which probably reflects the duration of endogenous GRF deficiency, and (c) although the PRL response to GRF is heterogeneous, it does in some patients provide additional evidence of responsive pituitary tissue.

Adolescent↗