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Biomedical subjects

A Hofmann

Publications and source records attributed to A Hofmann.

At least 109 records · Page 6Linked to original sources
PubMed1992

Hormonal responses to ingesting water or a carbohydrate beverage during a 2 h run.

Ingestion of fluids providing carbohydrate and electrolytes extends endurance times during prolonged exercise. To understand the contribution of these factors, we examined hormonal, physiologic, and metabolic responses to ingesting water (W) or a 7% glucose polymer/fructose/electrolyte solution (GPFE) in 10 men (age: 30 +/- 2 yr, VO2max: 57.4 +/- 3.2 ml.kg-1.min-1) who ran on a treadmill for 2 h at 60-65% of their VO2max. Subjects drank 200 ml of W or GPFE at 0-time and every 30 min while running (30,60, and 90 min). Changes in serum sodium, potassium, and osmolality; heart rate; plasma lactate and glucose; and serum insulin and plasma norepinephrine were similar for both fluid treatments. In contrast, changes in serum free fatty acids (FFA), plasma cortisol, and arginine vasopressin (AVP) differed across fluid treatments: with GPFE, exercise abolished the rise in plasma cortisol, and attenuated the rise in both AVP and FFA. The observed suppression of cortisol and AVP was not related to changes in any of the parameters examined, but were strongly correlated with each other. These findings suggest that adding carbohydrate and electrolytes to fluids ingested during prolonged exercise decreases activation of the hypothalamic-pituitary-adrenal axis, a potentially beneficial change. However, mobilization of FFA was also decreased. The mechanism by which they occur remains elusive.

Adult↗
PubMed1991

Faithful in vivo transcription termination of Xenopus laevis rDNA. Correlation of electron microscopic spread preparations with S1 transcript analysis.

DNA sequencing and subsequent functional in vitro analysis of the Xenopus laevis rDNA transcription termination has led to the identification of three transcription termination sequence elements: T1, located at the 3' end of the 28S rDNA; T2, a putative processing site 235 bp downstream of T1; T3, the principal terminator positioned 215 bp upstream of the gene promoter. As demonstrated for nuclear run-off assays, T3 was found to be the main terminator for Xenopus rDNA transcription. These in vitro data are in obvious contradiction to results obtained by electron microscopic (EM) spread preparations from rapidly isolated amplified oocyte nucleoli, i.e., an rDNA chromatin probe thought to represent the in vivo situation, indicative of transcription termination at sites T1-2. However, most interestingly, T3 had--again by the EM method--been identified as the exclusive terminator for NTS spacer transcription units. In order to answer the question of whether read-through transcription of the complete rDNA spacer sequence is obligatory for 40S pre-rRNA in vivo transcription, we analyzed several hundreds of spread rRNA genes from Xenopus oocyte nucleoli in great detail, applying two different spreading procedures, e.g., dispersal of amplified oocyte nucleoli shortly in detergent-free or detergent containing low-salt media prior to the EM spreading technique. Quantitation of EM spreads resulted in the finding that read-through rDNA spacer transcription beyond T1-2 termination sites (i.e., indicative of T3 transcription termination) can be visualized for the in vivo situation at a frequency of less than 3% of rRNA genes analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Plasma pyridoxal and pyridoxal 5'-phosphate concentrations in response to ingestion of water or glucose polymer during a 2-h run.

The effects of ingesting a glucose polymer solution (GP) or water (W) on plasma pyridoxal 5'-phosphate (PLP) and pyridoxal (PL) concentrations were compared in six men (age: 30 +/- 2 y; VO2max: 57.4 +/- 3.2 mL.kg-1.min-1) under running (R) and control (C) conditions. Subjects ran for 2 h at 60-65% of VO2max for R and remained standing for C. For both R and C, 200 mL W or GP was ingested before (0-time) and every 30 min while running (30, 60, and 90 min). Plasma PLP decreased to 95% and 87% of 0-time at 180 min for WC and GPC and increased to 126% and 119% at 90 min and to 124% and 119% at 120 min for WR and GPR. By 60 min postrun, plasma PLP was 98% (WR) and 101% (GPR) of 0-time. There were no significant differences between W and GP conditions. Changes in PLP were not related to plasma volume or blood glucose, free fatty acids, lactate, alkaline phosphatase, aspartate aminotransferase, or alanine aminotransferase. No significant changes in plasma PL were noted. Exercise induces an increase in plasma PLP, perhaps due to transfer of B-6 vitamers from liver to skeletal muscle.

Adult↗
PubMed1991

cis-acting sequences required for expression of the divergently transcribed Drosophila melanogaster Sgs-7 and Sgs-8 glue protein genes.

The Sgs-7 and Sgs-8 glue genes at 68C are divergently transcribed and are separated by 475 bp. Fusion genes with Adh or lacZ coding sequences were constructed, and the expression of these genes, with different amounts of upstream sequences present, was tested by a transient expression procedure and by germ line transformation. A cis-acting element for both genes is located asymmetrically in the intergenic region between -211 and -43 bp relative to Sgs-7. It is required for correct expression of both genes. This element can confer the stage- and tissue-specific expression pattern of glue genes on a heterologous promoter. An 86-bp portion of the element, from -133 to -48 bp relative to Sgs-7, is shown to be capable of enhancing the expression of a truncated and therefore weakly expressed Sgs-3 fusion gene. Recently described common sequence motifs of glue gene regulatory elements (T. Todo, M. Roark, K. Vijay Raghavan, C. A. Mayeda, and E.M. Meyerowitz, Mol. Cell. Biol. 10:5991-6002, 1990) are located within this 86-bp region.

Animals↗
PubMed1991

[The neuromuscular blocking effects of ORG 9426].

ORG 9426 is a new non-depolarizing steroidal muscle relaxant with a short onset time and intermediate duration of action. Its ED90 ist estimated to be between 0.25 and 0.36 mg/kg. The present study investigated the onset time, duration of action and time to spontaneous recovery after 0.3 and 0.9 mg/kg ORG 9426, respectively (i.e. about single or triple ED90). METHODS. Following the consent of the ethics committee and informed patient consent, two groups of 18 patients (ASA I or II) were formed, each scheduled for general or ORL surgery. After premedication with lormetazepam, anesthesia was induced with midazolam (0.07 mg/kg) and etomidate (0.3 mg/kg) and maintained with N2O/O2 at a 65:35 ratio, enflurane (0.8-1.5%) and supplements of fentanyl as needed. The ulnar nerve was stimulated with supramaximal 2 Hz Train-of-four (TOF) every 20 s. Neuromuscular twitch response was registered with EMG. Muscle relaxation was achieved by administration of ORG 9426 0.3 (group 1) and 0.9 mg/kg (group 2), respectively. The following parameters were measured: onset time (time interval from injection to maximal or total block), T125/75 (time for T1 to reach 25% or 75% of control), TOF70 (time for TOF ratio to reach 70% of control), heart rate and blood pressure. RESULTS. (mean +/- SD). At a dosage of 0.3 mg/kg, the onset time was 3.1 +/- 0.8 min and the maximum blockade was 87 +/- 9%. A dosage of 0.9 mg/kg led to complete paralysis (100%) in all patients within 1.2 +/- 0.3 min. The time for recovery of T1 to 25 and 75% of baseline was 18 +/- 7 and 26 +/- 8 min in group 1, in group 2 46 +/- 11 and 53 +/- 17 min, respectively. TOF70 (i.e., time to adequate spontaneous recovery of neuromuscular function) was achieved after 30 +/- 10 and 63 +/- 14 min, respectively. CONCLUSIONS. At a dosage of 0.3 mg/kg, ORG 9426 has an onset time of about 3 min and a duration of activity of nearly half an hour. Its neuromuscular effects are similar to a single ED90 dose of vecuronium. In contrast to a previous study, we observed a much shorter onset time of 70 s following the administration of 0.9 mg/kg. The clinical duration of action and spontaneous recovery of neuromuscular function, however, were significantly prolonged to more than 1 h. The hemodynamic parameters showed only slight alterations.

Adult↗
PubMed1991

[Surgical indications in bronchopulmonary malformations in childhood].

Especially in childhood, the diagnosis of bronchopulmonary malformations should be carried out to such an extent as to enable an appraisal of the probable further development of symptoms. If increasing complications and secondary damage are impending, there should be no hesitation in having surgical treatment carried out by an experienced thorax surgeon even in early childhood, if possible before an absolutely life-threatening situation is present. Without exception, there were no complications in the postoperative courses, and the good development of symptom-free children with normalized lung function document the rational justification for thorax surgery in various bronchopulmonary malformations.

Adolescent↗
PubMed1991

[Jena longitudinal study of growth of 0-3 year old children. 1: Average values of body height and body weight, somatograms and percentile values].

Normal values (means +/- s and percentiles) for body height and weight and a somatogram for children from the newborn period up to 3 years determined in 306 children (164 boys and 142 girls) are presented. Beyond the first year of life the children are slightly taller and have a reduced height related body weight in comparison to older standards.

Body Height↗
PubMed1991

[Jena longitudinal study of the growth of 0-3 year old children. 2: Percentile curves for body height, body weight, height related weight and growth rate].

Charts for body length and height, body weight, and height- and weight velocity basing on a longitudinal study with 306 children from the newborn age to 3 years of age, are presented. Length and weight velocity are strongest in the time between the 4th and 8th week of life. From the first to the fourth trimester velocities decrease continuously.

Adolescent↗
PubMed1990

Structural organization of Acheta rDNA. Evidence for differential amplification of soma and germ-line-specific rDNA sequences.

Amplification is one of the mechanisms whereby the expression of genes can be specifically reinforced. Ribosomal gene amplification in amphibian and insect oocytes is a particularly well documented case. We studied heterogeneity, amplification and size of Acheta domesticus (insects; Orthoptera) ribosomal DNA and characteristics of male and female somatic or germ line rDNAs by analysis of genomic clones from a conventional and a microclone library. The length of the Acheta rDNA repeat unit (transcription unit and non-transcribed spacer (NTS] varied from 47 x 10(3) to 60 x 10(3) base-pairs, with highest variability within the NTS region. Deletions, fragment length heterogeneity and size variability in small steps of individual NTS segments are responsible for the observed size variation. The number of rDNA repeat units per haploid genome of Acheta was determined as 190(+/- 10%). The rDNA is amplified 14(+/- 10%)-fold in the oocyte, producing about 10,000 gene copies per cell. Our results show that the amplification mechanism does not favor individual fragments within the repeat unit. Thus, it can be concluded that amplification does not change the chromosomal characteristics of the rDNA pool. Two fragments specific for oocyte rDNA suggest that the rearrangements accompanying amplification are preferentially located in one distinct EcoRI fragment. Certain regions of Acheta rDNA contain cell-type-specific fragments: it was thus possible to characterize one purely male fragment and a second one specific for male and female soma but not for germ line rDNA. We show that Acheta rDNA reveals a combination of many features reported from different organisms and novel tissue-specific alterations on an extremely large repeat unit. The tissue-specific alterations indicate sexual and soma/germ line differentiation events that are derived by as yet unknown mechanisms.

Animals↗
PubMed1990

Delta-9-tetrahydrocannabinol shows antispastic and analgesic effects in a single case double-blind trial.

A double-blind study was performed comparing 5 mg delta-9-tetrahydrocannabinol (THC) p.o., 50 mg codeine p.o., and placebo in a patient with spasticity and pain due to spinal cord injury. The three conditions were applied 18 times each in a randomized and balanced order. Delta-9-THC and codeine both had an analgesic effect in comparison with placebo. Only delta-9-THC showed a significant beneficial effect on spasticity. In the dosage of THC used no altered consciousness occurred.

Adult↗
PubMed1990

Promoter is an important determinant of developmentally regulated puffing at the Sgs-4 locus of Drosophila melanogaster.

Sgs-4 is one of the eight known genes coding for larval secretion proteins in Drosophila melanogaster. High-level transcription of the endogenous Sgs genes in salivary glands is accompanied by chromosome puffing at the Sgs gene loci. Naturally occurring mutations of the Sgs-4 promoter region diminish both the level of Sgs-4 expression and the puff size; in null-producers no puff is formed. P element-mediated transformation experiments were performed to clarify this apparent causal relation between transcription and puffing. Sgs-4 upstream sequences, unchanged or recombined with sequences from differently expressed alleles, were fused with Sgs-4 coding and downstream sequences or with the coding sequence of the viral oncogene v-mil. Analyses of the expression of these fragments at the RNA and protein levels and of their capacity for puff formation demonstrate uncoupling of transcription and puffing. That is, high-level transcription is independent of chromosome puffing and does not necessarily induce puffing, and developmentally regulated chromosome puffing is independent of significant transcriptional activity within the puff. Our results show that the strength of the Sgs-4 promoter located within the upstream region from -1 to -840 determines the formation of a puff. No specific effects could be detected on either transcription or puffing by decondensed versus compact chromatin adjoining the transposed DNA at the sites of insertion in transformants. A model in which trans-acting factors binding to the promoter region initiate puffing is proposed.

Animals↗
PubMed1990

Plasmid and bacteriophage lambda-DNA show differential replication characteristics following injection into fertilized eggs of Xenopus laevis: dependence on period and site of injection.

The fate of DNA injected into in vitro fertilized eggs of Xenopus laevis during subsequent early embryogenesis was investigated by changing the time period and the area of injection. Form I/II plasmid DNA was found to be preferentially replicated in embryos which had been injected 60-65 min after fertilization into the animal half of the fertilized egg, irrespective of the presence of a eukaryotic origin of replication sequence element in the DNA probe used for injection. In the experiments where plasmid DNA and lambda-DNA were coinjected, only the latter was actively replicated, which suggests an inhibitory activity of this DNA on replication of coinjected plasmid DNA.

Animals↗
PubMed1990

Toxicology and carcinogenesis studies of dietary titanium dioxide-coated mica in male and female Fischer 344 rats.

Male and female Fischer 344 rats were fed diets containing 0, 1.0, 2.0, or 5.0% titanium dioxide (TiO2) coated mica for up to 130 wk. This dosage regimen produced no consistent or biologically important changes in survival, body weight gains, hematologic or clinical chemistry parameters or histopathology. Under the conditions of this 130 wk feeding study there was no evidence that TiO2-coated mica produced either toxicologic or carcinogenic effects at dietary concentrations as high as 5.0%. The results suggest that dietary exposure to TiO2-coated mica does not pose a significant human health hazard.

Administration, Oral↗
PubMed1990

[Parietal pleurectomy in pleural cancer].

Exudative pleural carcinosis may remain the only localisation of generalized disease for months. Exudation and total distension of the lung must be prevented. Since sclerosis is not effective in cases of tapered lung, parietal pleurectomy and decortication are indicated. This ensures patient survival and fitness for work for several years.

Breast Neoplasms↗