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Biomedical subjects

J Holm

Publications and source records attributed to J Holm.

At least 253 records · Page 14Linked to original sources
PubMed1980

Capillary supply and muscle fibre types in patients with intermittent claudication: relationships between morphology and metabolism.

There have been previous reports on an increased oxidative capacity in muscle tissue from the diseased legs of patients with intermittent claudication. The present study was designed to correlate metabolic and morphological data and to investigate whether the metabolic adaptive changes in muscle tissue of claudicating legs were also reflected in morphological variables such as capillary supply, fibre type distribution, and fibre area. The activity of cytochrome-c-oxidase in gastrocnemius muscle was determined and the insulin and glucose uptakes were measured across the leg in the basal state and 10 min following intravenous administration of 25 g glucose. The finding of a reduced relative number of Type II B fibres and a reduced ratio Type II B/II A fibre area, as well as an increased capillary supply to Type II A, indicated that the most extensive morphologic changes in muscle tissue of claudicating legs had occurred in Type II fibres. The increased number of capillaries in contact with Type II A fibres in muscle tissue from claudicating legs, compared with muscle tissue from control legs, suggested that the most apparent metabolic changes occurred in this fibre type in the adaptation process of these patients. The more pronounced morphologic and metabolic changes in Type II fibres suggest that these fibres are more intensely activated than Type I fibres during physical activity in claudicating legs. The insulin uptake correlated positively with the number of capillaries per fibre, suggesting that the endothelial surface area is one of the determining factors for insulin uptake. The percentage of Type II B fibres reflected to a certain extent the metabolic adaptation in muscle tissue.

Aged↗
PubMed1980

A high affinity folate binding protein in umbilical cord serum.

Binding of [3H] folate to proteins in umbilical cord serum was studied in equilibrium dialysis experiments (37 degrees C, pH 7.4). A Scatchard analysis revealed the presence of high affinity (Kass = 9.10(10)1/mol, N = 0.5 nmol per 1 folate) and low affinity binding sites. High affinity binding was almost completely inhibited in the presence of methotrexate. A high affinity folate binding protein (saturated at a folate concentration of 10(-11)mol/l) appeared in the front effluent after application of serum to a DEAE-Sepharose Cl-6B column equilibrated with 0.05 mol/l imidazole buffer (pH, 6.3, 30 mmol/l NaCl), whereas low affinity binding activity mainly associated with albumin eluted from the column following a rise in the NaCl concentration to 1 mol/l. Low affinity binding predominated at folate concentrations above (10(-9) mol/l. The apparent molecular size of the high affinity binder was 35,000 as determined by gel filtration. The physiological role of the high affinity binder is obscure. However, it may represent an intracellular protein regulating folate stores, and its appearance in serum may be incidental to tissue turnover.

Carrier Proteins↗
PubMed1980

Cofactor in serum for high-affinity folate binding in milk.

Affinity-chromatographic purification of the folate-binding protein from whey of cow's milk results in the removal of a heat-resistant cofactor that is important in high-affinity folate binding (Biochim, Biophys. Acta 579: 479, 1979). Thus a shift from negative to positive cooperativity occurred in the presence of cofactor (Biochim, Biophys. Acta 579: 479, 1979). We demonstrate the presence of a similar cofactor in sera from men, pregnant women, and umbilical cords. Even highly diluted (10 000-fold) serum samples were active, and the cofactor was also present in erythrocyte hemolysates (10 000-fold diluted). The identity of the cofactor, which may act as an overall modulator of high-affinity folate binding, is still obscure.

Animals↗
PubMed1980

Chromatographic isolation and characterization of folate binding proteins in porcine intestinal epithelial brush border membrane.

Gel filtration studies on solubilized porcine intestinal epithelial brush border membranes labelled with [3H] folate revealed three distinct protein peaks, Mr approximately 25 000, Mr approximately 80 000 and Mr greater than 130 000 (listed in order of decreasing folate binding affinity). The two large molecular size proteins may represent polymerized forms of the Mr approximately 25 000 peak. Folate binding proteins were eluted in front effluent after DEAE-Sepharose CL-6 B chromatography (pH 6.3, 30 mM NaCl) of a solubilized membrane preparation. This means that the cationic forms of these proteins predominate at pH 6.3. In conclusion, folate binding in brush border membranes display characteristics in many respects similar to those of high-affinity folate binding in other tissues and body fluids.

Animals↗
PubMed1978

Effect of methotrexate on folate binding to a folate binding protein in cow's milk.

Folate in cow's milk was strongly bound to a minor whey protein. Methotrexate inhibited the folate binding in a log dosis dependent manner, but was a rather weak inhibitor. The binding mechanism of folate changed from a cooperative to a non-cooperative type in the presence of methotrexate. This model system could be used in investigations on human body fluids and tissues.

Animals↗
PubMed1978

Transport interaction phenomena between monoquaternary and polymethylene-bisquaternary amines in mouse kidney cortex slices.

The polymethylene-bisquaternary amine 14C-decamethonium accumulates in mouse kidney cortex slices incubated in Krebs-Ringer bicarbonate buffer (37 degrees C, pH 7.4) aerated with O2-CO2 95:5 v/v%. The accumulation rate was enhanced in the presence of monoquaternary amines which on the other hand depressed maximum accumulation ratio of decamethonium in the tissue. The stimulation phenomenon was apparently related to the intracellular concentration of monoquaternary amine since tissue preloaded with a monoquaternary amine took up decamethonium at an increased rate. This effect was due to an accelerated influx of decamethonium and not to inhibition of efflux since no decamethonium efflux was shown to occur in wash-out experiments. Flux stimulation may represent an interaction phenomenon of accelerative exchange diffusion type. Furthermore, various amines inhibited accumulation of decamethonium in a competitive manner. The study supports the idea that common steps are involved in cellular transport of monoquaternary and polymethylene-bisquaternary amines in the kidney.

Animals↗
PubMed1978

Ionic and metabolic requirements for decamethonium transport in mouse kidney cortex slices.

Decamethonium accumulates in mouse kidney cortex slices incubated in Krebs-Ringer bicarbonate buffer (37 degrees C, pH 7.4) aerated with O2-CO2 95:5 v/v%. Maximum tissue-medium accumulation ratio decreased with increasing external decamethonium concentration. Decamethonium was released from the tissue at a slow rate. The metabolic inhibitor cyanide inhibited accumulation of decamethonium but did not produce release of decamethonium already accumulated in the tissue. Substitution of external Na+ by other cations depressed decamethonium uptake. However, this cannot be ascribed to absence of Na+ since no inhibition occurred when Na+ was substituted by isoosmotic sucrose. Decamethonium uptake is inhibited when active Na+-transport is impaired (omission of K+ or addition of ouabain). The slow onset of this inhibition is compatible with the idea that it may be secondary to changes in the intracellular electrolyte concentrations. Furthermore, decamethonium uptake was depressed in absence of external Ca2+.

Animals↗
PubMed1978

Physical training of patients with intermittent claudication: indications, methods, and results.

Supervised dynamic physical training for 4 to 6 months as a treatment of intermittent claudication was studied in 148 patients who had clearcut symptoms for more than 6 months. Nineteen patients could not complete the planned training program because of cardiac complications, rapid progress of the disease, intercurrent disease, or social reasons. Before the training was started, walking tolerance and calf blood flow were determined. The intensity of each training session (three times per week) was adjusted to the patient's cardiac tolerance as predicted by the cardiac tolerance test. The walking ability increased in 88% of the patients and the average increase was 234%, while the calf blood flow remained unchanged. After the training period, more than 40% of the patients could walk 1,000 m or more. The increase in walking ability was independent of the location of the atherosclerotic lesion or the presence of diabetes. It is concluded that physical training is a good alternative to reconstructive surgery in the treatment of patients with intermittent claudication. It does not interfere with the surgical possibility if operation becomes necessary in the immediate or later course of the disease.

Adult↗
PubMed1977

Physical training in man. Skeletal muscle metabolism in relation to muscle morphology and running ability.

The metabolic and morphologic adaptation to physical training in skeletal muscle tissue of eleven middle-aged, physically untrained men was studied. Muscle biopsies were taken from the vastus lateralis before, after 8 weeks and after 6 months of physical training for analysis of metabolic and morphologic variables. Glucose tolerance test indicated increased insulin sensitivity after 6 months of physical training. The activities of glycogen phosphorylase, hexokinase and glucose-6-P-dehydrogenase were increased but other enzymes involved in glycogen turnover and glycolysis were unchanged after 6 months of physical traning. The activities of citrate synthase and cytochrome-c-oxidase, representing the oxidative capacity were significantly increased already after 8 weeks of physical training. The incorporation rate of palmitate-carbon into CO2 and triglycerides increased, and the incorporation rate of leucine-carbon into CO2 decreased with 6 months of physical training. The fiber diameter of both Type 1- and Type 2-fibers increased, while the mitochondrial volume increased predominantly in Type 2-fibers. Significant correlations were found between metabolic, physiologic and morphologic variables before and after physical training. The results indicate an increased oxidative capacity, mainly located to Type 2-fibers, and an increased utilization of fatty acids in response to this type of physical training.

Carnitine↗