Search PubMed⌕ Search

Biomedical subjects

H Christensen

Publications and source records attributed to H Christensen.

At least 271 records · Page 15Linked to original sources
PubMed1985

Plasma secretin in response to pure bile salts and endogenous bile in man.

The effect of exogenous bile salts on plasma concentrations of secretin was studied by infusion of chenodeoxycholate, cholate, glycocholate, and taurocholate into the duodenum of normal subjects. The effect of endogenous bile on plasma secretin was studied by ingestion of a liquid test meal, by reinfusion of postprandial duodenal aspirates with known contents of bile salts, and by stimulation of gallbladder contraction by cholecystokinin. Each experiment was performed in groups of seven subjects. The relative secretin-releasing potencies of glycocholate, cholate, taurocholate and chenodeoxycholate (2.25 mmol) were 1.0:1.3:1.9:3.2. Hydrochloric acid (0.5 mmol) was, on a molar basis, approximately ten times more potent than sodium cholate. The effect of taurocholate was diminished when a liquid meal was used as vehicle instead of saline. Endogenous bile did, in no circumstance, elicit release of secretin. It is concluded that although bile salts have the ability to stimulate secretin release, endogenous secretin release is of minor, if any, importance for secretin release when physiological conditions are approached.

Bile↗
PubMed1985

Pattern of electrical activity and force in normal and pathological muscle: S-index of turns and amplitude.

Cenkovich et al. (1982) found that a rotated hyperbolic curve fitted the relationship between the logarithm of cumulative amplitude (log A) and the logarithm of turns (log T). They found the intercept of the hyperbola (S-index) to be independent of force and suggested to use the S-index without measurement of the force as a diagnostic criterion. We have applied this modification of the method to our material previously published. In controls we found a slight increase in S-index with increasing force. The S-index was often increased in patients with myopathy and decreased in patients with neurogenic disorders, mostly at low to moderate force. The S-index was not better in discriminating patients from controls than the ratio of turns to mean amplitude.

Adolescent↗
PubMed1985

Oral hygiene instruction in general dental practice by means of self-teaching manuals.

The present study evaluates the applicability of delivering oral hygiene instruction to patients in general dental practice by means of self-educational programs. Patients (55) seeking dental treatment in 3 general dental practices in Denmark were divided at random into a conventional professional instruction group (C) in which each individual received personal instruction by the dentist and a self-instruction group (S), in which the patients were given self-educational programs. In order to evaluate the effect of the 2 types of instruction, the presence or absence of dento-gingival plaque and gingival bleeding by probing was recorded prior to the instruction and after 3 and 6 months. The patient of the self-instruction group (S) answered a questionnaire about the treatment 1 week after they had received the self-instruction program. An identical improvement in oral hygiene and gingival health was recorded in both treatment groups after 3 and 6 months. This finding indicates, that the self-educational programs were as effective in changing the oral hygiene habits of the patients as was personal oral hygiene instruction by dental personnel. The answers of the patients to the post-treatment questionnaire reflected a favorable attitude towards the use of self-educational programs.

Adult↗
PubMed1984

Processing of electrical activity in human muscle during a gradual increase in force.

The integrated electrical activity, the number of zero crossings and the number of turns, the mean amplitude and the ratio between them, of the electrical activity were compared in the brachial biceps muscle and the anterior tibial muscle of 20 controls. The electrical activity and force were analysed every 100 msec during a gradual increase in force from zero to maximum within 10 sec. The square root of integrated electrical activity increased linearly with increasing force. The slope of this relation was inversely related to maximum force when the increasing force was expressed in kilograms. The number of zero crossings per unit time increased with increasing force up to 40-60% of maximum force after which it remained constant. Comparison of 100 microV and 50 microV level detections suggested that there is a cancellation of small spike components in the electrical activity during higher force. The square root of integrated electrical activity was linearly related to mean amplitude between turns and the number of zero crossings was linearly related to the number of turns. In conclusion the information obtained by analysis of integrated activity and number of zero crossings is probably also obtained by number of turns and mean amplitude analysis.

Adolescent↗
PubMed1984

A novel approach for scanning electron microscopy of colloidal gold-labeled cell surfaces.

A method is described for the use of scanning electron microscopy on the surface of gold-labeled cells. It includes the use of 45- or 20-nm colloidal gold marker conjugated with Staphylococcal protein A. The marker is best recognized on the basis of its atomic number contrast by using the backscattered electron imaging mode of the scanning electron microscope. When the backscattered electron signal is mixed with the secondary electron signal, an optimum correlation between the distribution of the labeled sites and the cell surface structures is demonstrated. The method is illustrated by its application to the identification of human circulating granulocytes. Its good resolution, high contrast, and good labeling efficiency offers a promising approach to the specific localization of cell surface antigenic sites labeled with particles of colloidal gold.

Erythrocytes↗
PubMed1983

Axonal atrophy in sensory nerves of the diabetic BB-Wistar rat: a possible early correlate of human diabetic neuropathy.

Clinical, morphological, and biochemical findings reported in the spontaneously diabetic BB-Wistar rat strongly indicate that this animal may be a true model of human insulin-dependent diabetes mellitus. As such, it may provide a valuable model in which to study the neuropathic conditions of diabetes. We examined somatic peripheral nerves at five levels in a longitudinal fashion using quantitative morphological techniques. Myelinated fiber atrophy occurred earlier in sensory nerves than in motor nerves and showed a distal to proximal progression with duration of diabetes. Axon/myelin ratios revealed disproportionate shrinkage of axons evident already after 4 months of diabetes in the sural nerve and only after 8 months in the peroneal nerve. Endoneurial edema could not be demonstrated by morphometric means in diabetic nerves. We conclude that the distal symmetrical polyneuropathy in diabetes can be characterized as a mainly sensory axonopathy of dying-back type.

Animals↗
PubMed1982

The effects of sensory deprivation on cigarette craving and smoking behaviour.

Seventy two heavy smokers were treated by means of either 6, 12 or 24 hours of sensory deprivation, or by 24 hours of social isolation. There was a significant linear trend relating time in confinement to reduction in mean post-treatment smoking rate. A measure of cigarette craving while confined did not predict treatment outcome. Craving while confined for 24 hours exhibited a cubic trend, indicating a diurnal rhythm. Differences between the two 24 hour conditions were nonsignificant, but suggested that social isolation may be therapeutically preferable to sensory deprivation.

Cues↗
PubMed1977

Determination of dextropropoxyphene and norpropoxyphene in autopsy material.

A method for the simultaneous determination of dextropropoxyphene (DP) and its major metabolite norpropoxyphene (NP) in autopsy material, has been developed. By the extraction procedure used, NP is completely converted to its more stable amide form, which like DP, produces well-defined peaks, in the subsequent gas-liquid chromatographic determination. Thin-layer chromatography is used for additional identification of the two compounds. In 20 g of autopsy material, the detection limit is 0.3 mug/g of tissue or body fluid. The recovery of standards added to control blood samples (1.25 mug/g) was 65 +/- 10% (S.D.) for DP and 59 +/- 9% (S.D.) for NP (n = 54). The method is routinely used for determinations in blood, muscle, liver and urine.

Autopsy↗
PubMed1977

Dextropropoxyphene and norpropoxyphene in blood, muscle, liver and urine in fatal poisoning.

Post-mortem concentrations of dextropropoxyphene (DP) and its major metabolite norpropoxyphene (NP) were determined by combined gas-liquid chromatography and thin-layer chromatography in autopsy material from 53 cases of fatal DP poisoning collected over a 1-year period. Among 11 oral cases without simultaneous ethanol ingestion, the minimal lethal dose was less than 1.5 g DP chloride. The ranges of total drug concentrations (DP + NP) were 1.1-15 mug/g in blood, 1.3-23 mug/g in muscle, and 27-261 mug/g in liver. Among 21 oral cases were ethanol was detected in the blood, the minimal lethal dose was 0.7 g DP chloride (ethanol 2.41 mg/g) and the total drug concentrations was 0.7-12 mug/g in the blood, 1.3-8.4 mug/g in the muscle and 19-285 mug/g in the liver. The minimal lethal blood concentrations tended to decrease with increasing ethanol concentration. NP constituted roughly half of the total drug levels, somewhat less in muscle and more in the urine, and this pattern was not changed in connexion with ethanol ingestion. Other metabolites were not detected.

Autopsy↗