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Biomedical subjects

K Christensen

Publications and source records attributed to K Christensen.

At least 181 records · Page 10Linked to original sources
PubMed1990

Fractional processing of sequential bronchoalveolar lavage to separate bronchial and alveolar samples.

Bronchoalveolar lavage has been widely used to sample the lower respiratory tract. Most of the material recovered with this technique represents alveolar contents. A number of modifications have been suggested in order to obtain samples relatively enriched for bronchial material. In order to be able to use a standard technique for bronchoalveolar lavage to sample both airways and "routine" alveolar material, a simple modification of the technique as described by Reynolds and Newball was used: five sequential 20-ml aliquots were infused into the lower respiratory tract, and each aliquot was immediately aspirated. The return from the first aliquot was processed separately from the return from the subsequent four aliquots. These last four aliquots were pooled. Analysis of the first aliquot revealed it to be enriched for ciliated epithelial cells when compared with the subsequent aliquots. There were also differences in inflammatory cell composition with the bronchial sample containing relatively more neutrophils and relatively less lymphocytes. Aspiration during transoral bronchoscopy was documented by quantifying salivary amylase in the bronchial and alveolar lavage fluids. It was estimated, however, that the aspiration was not of quantitative significance in the vast majority of subjects studied. Finally, with the technique of fractional processing of bronchoalveolar lavage samples, it was possible to compare the protein concentrations in bronchial and alveolar lavages. Most prominent among the differences was a marked relative enrichment in the bronchial samples for immunoglobulin A. The technique of fractional processing of bronchoalveolar lavage samples provides a simple means to obtain samples enriched for bronchial and alveolar components. This should facilitate analysis of lower respiratory tract specimens in airway disease.

Adult↗
PubMed1990

Intestinal calcium transport in systemic disease. Studies with brush-border membrane vesicles.

Recent experiments utilizing brush-border membrane vesicles (BBMV) from small intestine to examine calcium uptake processes by the enterocyte are reviewed. Results demonstrate that (a) uptake must be examined in the time frame approaching initial rate, and (b) kinetics of saturable and nonsaturable processes be defined. Saturable uptake of calcium is carrier mediated, since it is inhibited competitively by strontium and noncompetitively by magnesium. Intravesicular strontium (but not magnesium), doubles Vmax for saturable uptake of calcium from the medium (countertransport), consistent with a mobile carrier. Since membrane lipid composition is expected to be an important determinant of function of a mobile carrier in a lipid bilayer, BBMV were treated with liposomes to change phospholipid and cholesterol content. Any change from native lipid composition decreased Vmax, but in treated BBMV, Vmax correlated with BBMV cholesterol content and fluidity. Since nonsaturable calcium uptake is extensively inhibited by both strontium and magnesium, electrostatic binding of calcium to the membrane is a major component of nonsaturable uptake. The remaining uninhibitable component of nonsaturable uptake is diffusion down the calcium concentration gradient. These concepts are applied to considering calcium uptake in disease and to the relationship of uptake to transenterocyte calcium movement.

Animals↗
PubMed1989

[General seizures in connection with an epidural blood patch].

A case is presented of a 60 year old woman with severe headache after spinal anaesthesia. She did not respond to fluid, rest in bed and analgesics, and was therefore treated with an epidural blood-patch. Immediately after the epidural needle was withdrawn the patient developed tonic convulsions for 10-15 seconds. After regaining consciousness she had amnesia but no neurological sequelae. The EEG was normal and the patient had no history of previous convulsions.

Anesthesia, Spinal↗
PubMed1989

[Treatment and socioeconomic consequences of skiing injuries in the County of Vejle during the 1986/1987 season].

In a prospective study conducted in the County of Vejle in the skiing-season 1986/1987, the hospitals were contacted by 129 persons who had skiing-injuries. Forty-one patients were primarily treated abroad and 35 patients were primarily examined or treated in Denmark after their return. Fifty-three patients who were injured in Denmark were primarily examined or treated in the casualty ward. The injuries the most often seen were knee and thumb-injuries. Twenty-three operations were undertaken, 15 on knees, and five on thumbs. A total of 139 bed-days were registered, 114 for injuries abroad and 25 for Danish injuries. Fifty-nine injured persons lost 1,481 days on account of sickness. The yearly nationwide costs for the health services in connection with skiing-injuries are calculated to be 9.2 million kroner (approximately 760,000 pounds). The expenses for loss from production are calculated to be 8.6 million kroner (approximately 716,000 pounds).

Athletic Injuries↗
PubMed1989

The excretion of prostacyclin (PGI2) in milk and its possible role as a vasodilator in the mammary gland of goats.

1. Prostacyclin production in mammary gland of two lactating goats measured as the excretion in milk of 6-ketoprostaglandin F1 alpha (6-KPGF1 alpha) was followed for 16 days before, during and after exogenous administration of recombinant bovine growth hormone (GH). 2. 6-KPGF1 alpha was detected in all milk samples in concentrations ranging from 32-99 pg/ml milk independently of the time of sampling. 3. GH-treatment significantly increased milk yield, the concentration and excretion of 6-KPGF1 alpha in milk. 4. The concentration of milk 6-KPGF1 alpha was positively correlated with milk yield in the high (R2 = 0.35), but not in the low yielding goat (R2 = 0.003). 5. The possible role of prostacyclin as a local vasodilator in the mammary gland of goats is discussed.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Evaluation of mammary blood flow measurements in lactating goats using the ultrasound Doppler principle.

1. Non-invasive methods were developed for measuring mammary blood flow in lactating goats. 2. A Doppler principle ultrasound device was equipped with an external detector measuring maximal blood velocity (Vmax) and average blood velocity (Vav) was calculated as Vmax/2. Volume flow then depended on determination of the angle of insonation and the cross-sectional area of the milk vein (the caudal superficial epigastric or subcutaneous abdominal vein). 3. Blood velocities were measured on the milk vein of either side of the animal while clamping the pudendal veins manually. Blood velocities ranged from 7-34 cm/sec. 4. The milk vein diameter was measured by means of a slide gauge which, for clearly protruding veins, gave similar results to that measured by ultrasound scanning. In protruding veins the cross-section was circular. In non-protruding veins the cross-section was elliptical and the slide gauge significantly (P less than 0.01) overestimated the cross-sectional area. The milk vein diameter of either side measured in 10 lactating goats was 8.8 +/- 1.1 mm (means +/- SD). 5. Blood flow ranged from 90-675 ml/min in a dry and a high-yielding (3.4 l milk daily) goat, respectively. The reproducibility of the blood flow measurements was 12-16%. 6. It is concluded that the present method may be used for quantitative measurements of mammary blood flow in goats.

Animals↗
PubMed1989

Calcium uptake by brush-border membrane vesicles from the rat intestine.

Uptake of calcium by brush-border membrane vesicles from rat small intestine is composed of saturable and nonsaturable components. We studied regulation of calcium uptake using the divalent cations strontium, a foreign ion that mimics calcium biologically and magnesium, a physiologically important ion that resembles calcium physically, although not biologically. Strontium present outside the vesicle inhibited saturable calcium uptake competitively, consistent with binding to the transporter at the same site as calcium. Strontium inside the vesicle accelerated saturable calcium uptake from the outside (countertransport), also consistent with binding to the same transporter site as calcium. Thus the calcium transporter shows functional characteristics of a mobile carrier. In the uptake medium (extracellular), magnesium was a noncompetitive inhibitor of saturable calcium transport, consistent with a regulatory role in calcium uptake by binding to the transporter at a locus other than that for calcium. Magnesium at 1 mM concentration inside the vesicle had no effect on saturable calcium uptake and a high concentrations functioned as a week uncompetitive inhibitor. Thus intracellular magnesium appears to have no major role in regulating saturable calcium uptake at the brush border of the enterocyte.

Animals↗
PubMed1988

Interactive effects of live weight, basal diet and fat supply on essential fatty acid status and blood concentrations of glucose, insulin and thyroxine measured postprandially in pigs.

1. The composition of the basal diet (purified vs complete feed ingredients provided as a cassava and a barley based diet, respectively), type of dietary fat [saturated fatty acids (18:0) supplied as fully hydrogenated soya bean oil vs unsaturated fatty acids (18:2) supplied in the form of soya bean oil] and the live wt of the animals (40 vs 80 kg) highly influenced the EFA status of the body and postprandial blood concentrations of glucose, insulin and thyroxine. 2. Interactive effects of live wt, type of basal diet and fat supply on EFA status and postprandial blood levels are discussed.

Animals↗
PubMed1988

Heat production in growing pigs calculated according to the RQ and CN methods.

1. Heat production, calculated according to the respiratory quotient methods, HE(RQ), and the carbon nitrogen balance method, HE(CN), was compared using the results from a total of 326 balance trials with 56 castrated male pigs fed different dietary composition and variable feed levels during the live wt range 20-120 kg. 2. HE(RQ) was generally higher than HE(CN). 3. HE(RQ) depended on feed composition and feed level and, consequently, on the synthesis and deposition of depot fat. For RQ-values above 1, HE(RQ) was overestimated. 4. HE(CN) was generally underestimated, because N- and C-balances in general were overestimated due to losses in excreta. 5. The difference between HE(RQ) and HE(CN) was not constant. It was smallest when fat synthesis and fat deposition were low (2-3.5%) and greatest when fat synthesis and fat deposition were high (7-9%). The presence of dietary fatty acids may affect the difference. 6. In pigs receiving a cereal based diet, HE(RQ) may be expected to give 3-4% higher values than HE(CN), but in case easily available carbohydrates (glucose, sucrose) or high-fibre diets are provided, the differences may be larger. 7. Both methods were carried out with similar accuracy and precision. The results indicated that both methods are equally reliable.

Animal Feed↗
PubMed1987

Methane excretion in the growing pig.

Total methane excretion (CH4 in breath + flatus) was measured in two experiments with thirty-six castrated male pigs (Danish Landrace) during the growth period from 20 to 120 kg live weight (LW). In Expt A, twenty-eight pigs were fed on a commercial diet alternately at high (HFL; metabolizable energy (ME) 1234 (SE 41) kJ/kg LW 0.75) or low (LFL; ME 784 (SE 31) kJ/kg LW 0.75) feed levels in different weight classes. In Expt B, eight pigs were constantly fed on a semi-purified diet at HFL without (-oil) or with 90 g soya-bean oil/kg diet (+oil) corresponding to daily intakes of ME of 1339 (SE 11) and 1413 (SE 8) kJ/kg LW 0.75 respectively. CH4 excretion was measured during 24 h respiration trials in open-air-circulation chambers. About 1 litre CH4 was excreted per day at 20-25 kg LW increasing to a maximum of 12 litres at 120 kg LW, which corresponded to no more than 1.2% of dietary gross energy. In Expt A, CH4 excretion increased linearly with LW, while in Expt B the increase was linear until about 70 kg LW, when it reached a plateau. On average LFL reduced CH4 excretion by 23% compared with HFL. When related to dry matter (DM) intake, however, the pigs on LFL excreted 3.1 litres CH4/kg dietary DM and those on HFL 2.5 litres CH4/kg dietary DM, the difference being significant (P less than 0.05). In Expt B the inclusion of soya-bean oil in the basal diet (+oil) reduced CH4 excretion by 26% compared with the diet without oil (-oil).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1987

Intestinal disaccharidase activity following pancreatic duct occlusion in the rat.

The influence of pancreatic secretions on growth and brush-border enzyme activity, throughout the entire small intestine, was examined in the rat. Pancreatic secretions were excluded from the gut lumen by stapling the pancreatic ducts, without interruption of bile flow. The entire small intestine was studied as four segments; the duodenum and three distal segments of equal length. Weight of intestine and mucosa, and mucosal sucrase, isomaltase, lactase, and alkaline phosphatase activity were measured 10-15 days following pancreatic duct occlusion, or sham-operation. The duodenum of pancreatic duct-occluded animals exhibited significant hypertrophy. In general, specific and total disaccharidase activities were greater in duct-occluded animals than in controls throughout the intestine. The increase was more pronounced in distal than in proximal segments. The sucrase/isomaltase ratio was significantly greater in pancreatic duct-occluded animals than in controls in the two distal segments. Alkaline phosphatase activity was not affected by pancreatic duct occlusion. The greater relative increase of disaccharidase activities and sucrase/isomaltase activity ratios in the distal segments of duct-occluded animals, indicates a more important regulatory role of pancreatic enzymes in the distal small intestine. It is concluded that regulation of intestinal brush-border enzyme activity by pancreatic secretion is selective for enzyme and site as follows: disaccharidases, but not alkaline phosphatase, are regulated; the sucrase subunit of the sucrase/isomaltase complex is most sensitive to regulation, while lactase is least sensitive; and the regulatory effect on disaccharidases is greater in distal than in proximal intestine.

Animals↗