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Biomedical subjects

J Dahl

Publications and source records attributed to J Dahl.

At least 19 recordsLinked to original sources
PubMed1992

Functional asymmetry of the regions juxtaposed to the membrane-binding sequence of polyomavirus middle T antigen.

The functional importance of the two clusters of positively charged amino acids which flank the hydrophobic membrane-anchoring sequence of polyomavirus middle T (mT) protein has been investigated by using site-directed mutagenesis. A clear asymmetry was apparent. No effect on transformation was seen following multiple alterations or complete removal of the cluster at the carboxyl end of the protein. In contrast, a single substitution replacing the first arginine amino terminal to the hydrophobic stretch with glutamic acid, but not with lysine, histidine, or methionine, produced a partially transformation-defective mutant with a novel phenotype. This mutant failed to confer anchorage-independent growth on F111 established rat embryo fibroblasts but induced foci with altered morphology compared with wild-type mT. Biochemical studies on this mutant revealed that F111 clones expressing levels of mutant mT equivalent to those of wild-type controls showed a 65% reduction in pp60c-src activation and an 87% reduction in mT-associated phosphatidylinositol 3-kinase activity. However, F111 clones expressing seven times more mutant mT than did wild-type controls showed equal or greater levels of kinase activities yet remained incompletely transformed. Possible mechanisms involving this transformation-sensitive region of mT are discussed.

Animals↗
PubMed1991

Behavioral medicine treatment in chronic constipation with paradoxical anal sphincter contraction.

Nine women and five children with severe chronic constipation received behavioral medicine therapy. Before treatment, all patients had a paradoxical contraction of the external anal sphincter at defecation attempts as demonstrated with electromyography and/or anorectal manometry. An electromyographic biofeedback device connected to an anal probe was used for the training that was performed on a regular toilet seat during five 1-hour sessions. Thirteen of the patients improved considerably and could learn to defecate spontaneously, and the use of laxatives ceased or diminished. Simultaneously with improvement, the paradoxical anal contraction disappeared. The results remained after 6 months, although two of the patients had received booster sessions of biofeedback training during follow-up.

Adolescent↗
PubMed1990

Effect of chlorhexidine scrub on postoperative bacterial counts.

Chlorhexidine surgical scrub was left on the surgeon's hands in 50 orthopedic and vascular surgical procedures to determine whether the number of bacteria on the hands could be decreased postoperatively. After a standard 5-minute scrub, one hand was randomly rinsed prior to gloving; the other was lightly patted with a sterile towel, leaving some foam on the hand. The surgeon then gloved and performed the procedure in the usual manner. After the operation, both hands were immersed in a tryptic soy broth for 30 seconds. The broth was then cultured for bacterial species and number. Cases in which glove puncture occurred were not cultured. The results were analyzed using the Wilcoxon signed-rank test. There were fewer bacterial colonies isolated from the hand coated with chlorhexidine scrub versus the other; this difference was statistically significant (p less than 0.005). There also seemed to be a trend towards higher bacterial counts after longer operations; however, the difference was not significant. Neither surgeon noted any evidence of dermatitis during the study. These results suggest that leaving chlorhexidine scrub on the hands during surgery can lead to lower bacterial counts on the surgeon's hands and less chance of wound contamination should glove puncture occur.

Antisepsis↗
PubMed1990

Short term inhalation of bromobenzene: methodology and absorption characteristics in mouse, rat and rabbit.

In a dynamic inhalation system, mice, rats and rabbits were exposed to bromobenzene vapour (250-3400 p.p.m.) for 4 hr. Blood concentrations of bromobenzene were determined by head-space gas chromatography. After inhalation of 1000 p.p.m. for 4 hr, concentrations of 153, 102 and 47 micrograms bromobenzene/ml blood were found in mice, rats and rabbits, respectively. In vitro experiments showed a blood/air partition coefficient at 37 degrees of approximately 200, which was reflected by a linear uptake of bromobenzene up to an air concentration of 2500 p.p.m. Compared with results obtained previously by intraperitoneal bromobenzene administration inhalation resulted in higher blood concentrations.

Absorption↗
PubMed1990

Effects of a behavioral treatment program on children with asthma.

Twenty children with severe asthma using continual oral beta 2 agonists were randomized equally into either a behavioral intervention group or a control group. The behavioral intervention consisted of: symptom discrimination of asthma signals, self-management techniques of breathlessness, and contingency management of asthma-related behavior. The purpose of the study was to evaluate the effects of the behavioral treatment when superimposed on a regular medical treatment. The design consisted of a four-week baseline period, a four-week intervention period, and a four-week follow-up period. Results showed that the group receiving the behavioral intervention significantly reduced their use of beta 2 agonist spray doses and days of school absenteeism without increasing the number of asthma symptoms compared with the control group. It was concluded that children with severe asthma may benefit substantially from a behavioral program in addition to their regular medical treatment.

Absenteeism↗
PubMed1989

Phosphorylation of middle T by pp60c-src: a switch for binding of phosphatidylinositol 3-kinase and optimal tumorigenesis.

Substitution of phenylalanine for tyrosine 315 of the polyoma virus middle T (mT) protein lowers the incidence and limits the spectrum of tumors induced following inoculation of the virus into newborn mice. This substitution removes the major site of phosphorylation by pp60c-src without altering the ability of mT to associate with or to activate pp60c-src. The mutant mT fails to show binding of a phosphatidylinositol 3-kinase (Ptdlns 3-kinase) activity that is normally present in wild-type mT complexes. Furthermore, an anti-peptide antiserum that specifically recognizes mT lacking phosphate at tyrosine 315 precipitates binary (mT-pp60c-src) but not ternary (mT-pp60c-src-Ptdlns 3-kinase) complexes from wild-type infected cell extracts. Reprecipitation with either anti-pp60c-src or anti-mT serum brings down ternary complexes containing mT phosphorylated on tyrosine 315. Phosphorylation of mT by pp60c-src in vivo is therefore a critical event for binding of Ptdlns 3-kinase and for expression of the full tumorigenic potential of the virus.

Amino Acid Sequence↗
PubMed1988

Auditory function in sickle cell anemia.

Auditory acuity and central auditory processing were assessed in 22 patients with sickle cell anemia, 13 of whom were chronically transfused, and compared with a control black population. Pure tone air conduction thresholds were within normal limits for all patients, and mean Speech Reception Threshold for each ear was normal at 10 dB. All subjects exhibited type A tympanograms. Central auditory processing was assessed by the Competing Sentence Test and Binaural Fusion Test. No significant differences were found among transfused, nontransfused, and control patients. Abnormal auditory function does not appear to be a common problem in patients with sickle cell disease.

Adolescent↗
PubMed1988

Uptake of fatty acids by Mycoplasma capricolum.

The energy requirements for fatty acid uptake by Mycoplasma capricolum were studied. Fatty acid transport and esterification to phospholipid appeared to be tightly coupled, since there was little intracellular accumulation of free fatty acid. Uptake was blocked by iodoacetate, n-ethylmaleimide, and p-chloromercuribenzoate. Glucose, glycerol, and potassium ions were necessary for fatty acid uptake by whole cells. A reduction in uptake was observed in cells treated with valinomycin or dicyclohexylcarbodiimide. The effect of temperature on the rate of oleate uptake showed a discontinuity at 24 degrees C. Above 24 degrees C an energy of activation of 4.6 kcal (ca. 19.2 kJ)/mol was obtained. The data suggest that uptake of fatty acid by M. capricolum is an energy-linked, protein-mediated process. A membrane-bound enzyme activity that catalyzed the synthesis of fatty acyl-hydroxamate was demonstrated. This activity was virtually independent or only marginally dependent on coenzyme A, depending on the assay system, but was stimulated approximately twofold by ATP.

Biological Transport↗
PubMed1987

A protein kinase antigenically related to pp60v-src possibly involved in yeast cell cycle control: positive in vivo regulation by sterol.

The effects of ergosterol, yeast's natural sterol, on cell cycling and a protein kinase antigenically related to pp60v-src were examined in a sterol auxotroph of Saccharomyces cerevisiae. Sterol-depleted cells accumulate in an unbudded, G1 state. Cell budding and proliferation are reinitiated upon addition of nonlimiting ergosterol or cholesterol with trace ergosterol, whereas cholesterol or trace ergosterol alone is less effective. Stimulation of a protein kinase associated with immune complexes of yeast protein and anti-pp60v-src shows a positive correlation with exit from the G1 phase following ergosterol addition. Ergosterol-stimulated cells also demonstrate an increase in phosphatidylinositol kinase activity. The data suggest that hormonal levels of ergosterol (effective concentration, approximately equal to 1 nM) participate in a signaling process associated with a protein kinase possibly involved in yeast cell cycle control.

Cell Cycle↗
PubMed1985

Effects of low and high carbohydrate feedings in ambulatory patients with chronic obstructive pulmonary disease and chronic hypercapnia.

In a randomized, double-blinded study, patients with chronic obstructive pulmonary disease and hypercapnia were fed low, moderate, and high carbohydrate diets to determine the effect on metabolic and ventilatory values. The low carbohydrate diet consisted of 28% carbohydrate calories and 55% fat calories and resulted in significantly lower production of CO2 (p less than 0.002), respiratory quotient (p less than 0.001), and arterial Pco2 (p less than 0.05). At the end of the 15-day study, both the forced vital capacity (p less than 0.05) and the forced expiratory volume in 1 second (p less than 0.05) had improved by 22% over baseline values. Total calories given surpassed daily caloric requirements. This approach, together with a low carbohydrate, high fat mixture, may be beneficial for such patients.

Carbon Dioxide↗
PubMed1980

Factors influencing seizure duration and number of seizures applied in unilateral electroconvulsive therapy. Anaesthetics and benzodiazepines.

A certain minimum in the duration of seizures appears to be a condition for a satisfactory therapeutic effect in ECT. The aim of the present investigation is to elucidate the importance of some factors which may influence the seizure duration. In a controlled double-blind investigation with crossover, carried out on 19 patients, thiopentone and methohexitone were compared as anaesthetics for unilateral ECT. No differences were found between the anaesthetics regarding duration of seizures, number of treatments with insufficient seizures duration or amount of energy applied. Blood pressure measured after the seizure was slightly higher with thiopentone than with methohexitone and methohexitone as anaesthetic for ECT. In a retrospective investigation concerning seizure duration in unilateral ECT, patients given benzodiazepines during the treatment period were compared with patients who received no such medication. The benzodiazepine group showed shorter seizure duration, more cases with insufficient seizure duration and a need for a greater number of treatments. Benzodiazepines should be administered with caution during ECT, as they can impair the efficacy of treatments and consequently prolong the treatment period.

Adult↗
PubMed1978

[Therapy and therapeutic results in malignant ovarian tumors (exerience report 1945--1976)].

The study is the result of the medical histories from the Womens Hospital Cottbus from 1945 to 1976 with 387 malignoms of the ovary. The patients material is classified according therapeutic groups. The 5-year survival rates of 345 patients from 1945 to 1971 are 25,9%. The therapy of the ovarian malignoma consists of a combination therapy comprising, according to the stage, operation, radiation therapy and, since 1959 application of cytostatica.

Adult↗