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Biomedical subjects

J Knudsen

Publications and source records attributed to J Knudsen.

At least 127 records · Page 7Linked to original sources
PubMed1984

Triacylglycerol synthesis in goat mammary gland. Factors influencing the esterification of fatty acids synthesized de novo.

ATP alone had no effect on incorporation of fatty acids synthesized de novo and membrane-bound diacylglycerol into triacylglycerol. Combined addition of ATP and Mg2+ totally inhibits incorporation of fatty acids synthesized de novo and stimulated incorporation of membrane-bound diacylglycerol. ATP, Mg2+ and glycerol 3-phosphate stimulate incorporation of fatty acids synthesized de novo into triacylglycerol, but inhibited the incorporation of membrane-bound diacylglycerol. Diacylglycerol generated in situ was shown to be superior to diacylglycerols preloaded on the membrane as substrate for the diacylglycerol acyltransferase. A model is proposed to explain the effect of absorbed exogenous fatty acid on fatty acid synthesis de novo in goat mammary gland.

Acyltransferases↗
PubMed1984

Enzyme-linked immunosorbent assay (ELISA) studies of the interaction between mammalian and avian anti-thermogenin antibodies and brown-adipose-tissue mitochondria from different species.

Three different antibody preparations, rabbit anti-hamster and rabbit anti-rat thermogenin sera and chicken anti-rat thermogenin IgG, were tested for cross-reactivity towards isolated thermogenin and BAT mitochondria from different mammalian species using an ELISA-technique. It was found that the antibody preparations readily cross-reacted with different species, but that the affinity of the antibody preparations was greater towards the homologous species than the other species. The reactivity of an antibody preparation towards mitochondria from different tissues from the homologous species was also tested, and the exclusive occurrence of thermogenin in BAT could be confirmed.

Acclimatization↗
PubMed1984

Surgical management of intestinal obstruction in the late course of malignant disease.

Intra-abdominal and pelvic malignancies not infrequently are complicated by intestinal obstruction during their progressive course. How energetically this complication should be treated is a matter of controversy. An analysis of 41 such cases is presented. Small-bowel obstruction was most commonly caused by extensive serosal carcinomatosis, whereas obstruction of the large bowel usually was due to a single tumor. There was good concordance between the preoperative assessment of blockage level (small v. large bowel) and peroperative findings. All the patients with colonic obstruction obtained palliation from surgery, with median duration 6 months. Only 63% of the patients with small-bowel obstruction were relieved. This figure fell to 44%, with median duration of relief only 2 months, when carcinomatosis was the causal condition. The corresponding figures for patients with block caused by a single tumor were 89% and 6 months. Intestinal obstruction from non-malignant mechanisms was relieved in all cases. Surgical exploration should be attempted in these patients, as conservative measures are known to be of little benefit. In patients with extensive carcinomatosis, however, a favorable outcome in terms of symptom relief and prolonged survival is relatively unlikely.

Adolescent↗
PubMed1983

Medium-chain fatty acid synthesis by goat mammary-gland fatty acid synthetase. The effect of limited proteolysis.

Fatty acid synthetase from goat mammary gland was subjected to limited proteolysis by trypsin and elastase. Both proteolytic enzymes selectively cleaved the chain-terminating thioester hydrolase component from the enzyme complex, leaving all other partial activities intact in the core peptides. Trypsin, but not elastase, caused extensive degradation of the released thioester hydrolase. The released thioester hydrolase could be purified to homogeneity by gel filtration. The molecular weight was estimated as 29 000 and the enzyme showed only significant hydrolytic activity toward long-chain acyl-CoA esters. The core peptides retained the ability to synthesize medium-chain acyl-CoA esters in the presence of 2,6-di-O-methyl-alpha-cyclodextrin. The results conclusively show that the terminating thioester hydrolase of goat mammary-gland fatty acid synthetase is not involved in termination of medium-chain-length fatty acid synthesis by this enzyme.

Animals↗
PubMed1982

Continuous flow microcalorimetric measurement of heat production in white adipose tissue from obese (ob/ob) mice and their lean littermates.

Heat production, free fatty acid and glycerol release from white adipose tissue fat pads from obese (ob/ob) mice and their lean littermates are determined. Heat production was significantly lower in obese mice compared to lean mice when expressed on wet weight basis but not when expressed on DNA basis. Noradrenaline significantly increased the heat production in fat pads from both groups of animals. However, the increase in heat production due to noradrenaline addition in fat pads from lean mice was significantly higher than in fat pads from obese mice. The release of free fatty acids and glycerol before incubation with noradrenaline was similar from fat pads from both groups of animals. Addition of noradrenaline to the fat pads increased the release of free fatty acids and glycerol in both groups of animals, but the increase was significantly larger from fat pads from lean mice. In the absence of noradrenaline the free fatty acid/glycerol ratio (mol/mol) in the effluent was 7.9:1 and 4.8:1 for lean mice and obese mice, respectively. In the presence of noradrenaline the ratio decreased to 3:1 for both groups of animals.

Adipose Tissue↗
PubMed1982

Transacylation as a chain-termination mechanism in fatty acid synthesis by mammalian fatty acid synthetase. Synthesis of medium-chain-length (C8-C12) acyl-CoA esters by goat mammary-gland fatty acid synthetase.

1. Ruminant mammary-gland fatty acid synthetases can, in contrast with non-ruminant mammary enzymes, synthesize medium-chain fatty acids. 2. Medium-chain fatty acids are only synthesized in the presence of a fatty acid-removing system such as albumin, beta-lactoglobulin or methylated cyclodextrin. 3. The short- and medium-chain fatty acids synthesized were released as acyl-CoA esters from the fatty acid synthetase.

Acyl Coenzyme A↗
PubMed1982

A comparative study of intramuscular buprenorphine and morphine in the treatment of chronic pain of malignant origin.

1 Twenty-seven patients with moderate to severe chronic pain of malignant origin received buprenorphine (0.3 mg) and morphine (10 mg) intramuscularly in a double-blind, single dose within patient study. 2 Efficacy analysis demonstrated no significant differences in the peak analgesic effects or in the time to reach these effects. However, buprenorphine had a significantly longer duration of action than morphine. 3 Sedation was the most frequent unwanted effect with a similar incidence following each treatment. Buprenorphine was associated with a significantly higher incidence, greater severity, earlier onset, and longer duration of dizziness, nausea and vomiting than morphine. 4 Following both treatments there were small but significant decreases in pulse rate, blood pressure, and respiratory rate.

Adult↗
PubMed1982

Does the patient appear acutely or chronically ill? An interobserver study of global assessments of hospital patients.

The general appearance of 201 patients was assessed by a team of observers. Each patient was seen by two experienced physicians, two junior physicians and two medical students who stated whether the patients did not appear ill or whether the patient appeared acutely or chronically ill. The interobserver variation was considerable and the kappa-values ranged from around 0 to 0.75. The level of agreement did not seem to depend on the clinical experience of the observers. One experienced clinician assessed the patients differently from the others.

Acute Disease↗
PubMed1981

Whole gut irrigation with saline, tinidazole and colistin before colorectal operations.

To date, 27 patients scheduled for colorectal operations have had their bowels prepared the day before operation by whole gut irrigation with up to 151 of an electrolyte solution (14 patients), while the other 13 patients had infused in addition 0.51 of a solution containing 500 mg tinidazole and 1 MIU colistin. During the operation, samples were taken from the abdominal and perineal operation wounds and the colorectal mucosa by a velvet pad rinse technique, which involved transportation in a CO2-atmosphere and cultivation in an anaerobic cabinet. The number of anaerobic bacteria present in the colon was significantly lower after the use of antimicrobials, while there was no such difference with regard to aerobic bacteria. There were no differences between the two groups in preclosure bacterial densities of abdominal and perineal wounds. The total number of bacteria inoculated, the wound inoculum, was considerably lower after antimicrobial administration. There were no infections in the 13 patients treated with these antimicrobials, while 4 out of the 14 patients in the control group developed infections.

Adult↗
PubMed1980

Factors influencing the in vitro activity of diacylglycerol acyltransferase from bovine mammary gland and liver towards butyryl-CoA and palmitoyl-CoA.

1. Factors affecting the incorporation of butyrate relative to palmitate into the sn-3 position of triacylglycerol by the diacylglycerol acyltransferase from bovine mammary gland and liver was studied in vitro. 2. Butyrate incorporation from butyryl-CoA in the presence of palmitoyl-CoA was favoured by a high concentration of butyryl-CoA and by the presence of a long-chain acyl-CoA binding protein such as bovine serum albumin. 3. The relative activity of the enzyme from both tissues towards butyryl-CoA and palmitoyl-CoA was independent of the concentration of membrane-bound 1,2-dipalmitoylglycerol. 4. The significance of these results in relation to the unique presence of short-chain acids in ruminant milk triacylglycerols is discussed.

Acyl Coenzyme A↗
PubMed1980

Transacylation as a chain-termination mechanism in fatty acid synthesis by mammalian fatty acid synthetase. Synthesis of butyrate and hexanoate by lactating cow mammary gland fatty acid synthetase.

1. Purified cow mammary gland fatty acid synthetase synthesized long-chain unesterified and short-chain esterified fatty acids. 2. A direct relationship was observed between the amount of short-chain products synthesized and the concentration of acetyl-CoA in the incubation medium. 3. The short-chain products were identified as butyryl-CoA and hexanoyl-CoA. 4. Inhibition of the terminating thioester hydrolase of the fatty acid synthetase complex with phenylmethanesulphonyl fluoride did not inhibit the synthesis of short-chain products. 5. It is suggested that the synthesis of short-chain fatty acids involves the reverse of the 'loading' reaction.

Animals↗