[A functioning classification system for primary health care now exists].
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Classification↗
Biomedical subjects
S Nissen
Publications and source records attributed to S Nissen.
Localization of fibronectin in the initial lymphatics and blood vessels of normal human skin: an immunoelectron microscopic investigation.
The initial lymphatics of the human skin do not possess a basal lamina, but a subendothelial fibrous network, of which we do not know the biochemical and immunohistological composition. We investigated the wall of blood vessels and initial lymphatics in normal human skin for the presence of fibronectin by immunoelectron microscopy. We found discontinuous linear subendothelial diaminobenzidine (DAB) reaction products in both blood vessels and lymphatics. In addition fibronectin could be found at the anchoring fibrils of the initial lymphatics.
Adult↗
Ultrastructural studies on the invasion of melanomas in initial lymphatics of human skin.
The way in which melanoma cells invade the initial lymphatics of the skin was investigated in this study. Samples of sixty melanomas were examined by transmission electron microscopy. Tumor cells invading lymph vessels were demonstrated in 20 specimens. In most cases the melanomas penetrated the subendothelial space as single cells. These fused with the endothelial cytoplasmic membrane and subsequently destroyed the endothelial wall.
Humans↗
Oxidation of leucine and alpha-ketoisocaproate to beta-hydroxy-beta-methylbutyrate in vivo.
The oxidation of alpha-ketoisocaproate (KIC) to beta-hydroxy-beta-methylbutyrate (HMB) by the enzyme KIC dioxygenase has been previously described in rat and human liver; however, the importance of this pathway in normal leucine metabolism has not yet been assessed. A series of experiments was conducted in young lambs and pigs to determine whether HMB is produced from KIC in vivo and to estimate the importance of this pathway in leucine metabolism. In the first study, lambs were fed a bolus of KIC, and the change in plasma HMB concentration was monitored over a 24-h period. Administration of KIC increased plasma HMB from basal concentrations of 2 to approximately 7 microM 4 h after the supplementation. In the second experiment, lambs were infused with [6,6,6-2H3]KIC into the duodenum, and the appearance of labeled [2H3]HMB was measured. Under basal conditions, a minimum of 18% of the HMB was derived from KIC, but when unlabeled KIC was infused into the duodenum at a rate of 1.6 mumol.kg-1.min-1, plasma HMB concentration doubled, and essentially 100% of the HMB present was derived from KIC. In a third experiment, young pigs were infused with [6,6,6-2H3]leucine. At steady state, [2H3]-leucine and HMB enrichments were nearly identical, indicating that plasma HMB is derived solely from leucine. In a fourth experiment, both lambs and pigs were injected intravenously with 600 mg of HMB daily, and urinary HMB excretion was quantitated.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Histological demonstration of initial lymphatics in human skin: comparison between different extension techniques.
Initial lymphatic vessels (IL) are difficult to demonstrate histologically in excised normal skin, as they are usually completely collapsed. In this report three different methods (vacuum extension, large traction extension, and small traction extension) are described by which human skin specimens can be mechanically extended. After extension specimens were Epon enbedded and the IL counted and their diameters measured. The greatest number of lymphatic vessels was found in specimens extended by vacuum, and the smallest number in small specimens extended by traction. The highest density of lymphatic vessels was found 50-300 microns below the epidermis. Our data reveal that vacuum extension is useful for investigating questions concerning the topography of IL, whereas preparations extended by traction are more suitable for obtaining information about single lymphatic vessels.
Adult↗
Demonstration of initial lymphatics in excised human skin using an extension technique and dye injection.
Using a newly developed technique (extension technique) we succeeded in presenting dermal lymph vessel networks by subepidermal injection of an aqueous Berlin blue solution in excised human skin. Of 94 skin specimens taken from the safety margin of excised melanomas it was possible to demonstrate 32 networks and 14 single dermal lymph vessels. The networks can be documented by macroscopic photographs. Acetic fixation enables us to produce transparent preparations suitable for investigations with a stereo-microscope. The technique described here for macroscopically demonstrating dermal lymph vessels makes it possible to investigate systemically structural variations of lymph vessel networks in human skin.
Acetates↗
Influence of alpha-ketoisocaproate on lamb growth, feed conversion, and carcass composition.
Four experiments were conducted to determine whether leucine's alpha-ketoacid, alpha-ketoisocaproate (KIC), would influence lamb growth, feed conversion, and carcass composition. In the first experiment, lambs were injected intraperitoneally with 3.5 g of Na-KIC per day. In the second experiment, KIC unprotected from rumen degradation was fed at a rate of 15 g per animal daily. In a third experiment, KIC, leucine, and isovalerate (IVA), protected from rumen degradation, were fed to growing lambs at a rate of 1 g per animal per day. Finally, a fourth experiment was conducted in which ruminally protected KIC was fed to growing lambs at a rate of 1 g per animal per day. Ketoisocaproate tended to increase ADG and decrease fat deposition in all four experiments. Ketoisocaproate increased ADG by 11 (P less than .09), 10 (P less than .05), 9, and 13% in 1 through 4, respectively, and feed efficiency improved 5, 9 (P less than .02), 5, and 5%, respectively. Fat thickness over the 12th rib decreased 28 (P less than .06), 11, 17 (P less than .04), and 5% in Exp. 1 through 4, and the perirenal fat depot also decreased 13, 5, 18, and 3%, respectively. In contrast, neither ruminally protected leucine nor IVA affected the growth of young lambs. Together these studies indicate that administration of KIC to growing lambs can increase weight gain and muscle growth while decreasing fat deposition.
Adipose Tissue↗
Effects of alpha-ketoisocaproate on adrenocorticotropin-induced suppression of lymphocyte function in sheep.
Previous studies of the amino acid analogue, alpha-ketoisocaproate (KIC), indicate that it can stimulate lymphocyte blastogenesis and antibody responses of sheep. To determine whether KIC could overcome the effects of adrenocorticotropic hormone (ACTH)-induced lymphocyte suppression, 24 lambs were fed a control diet, a diet supplemented with 0.05% KIC, or a diet supplemented with 0.05% of the parent amino acid leucine. Immune status was monitored by determining lymphocyte blastogenic responsiveness to phytohemagglutinin-P (PHA), concanavalin A (conA), and pokeweed mitogen (PWM) and percentages of T-cell subsets in the blood, using monoclonal antibodies and a flow cytometer. Serum cortisol, insulin, and glucagon concentrations also were determined. After 60 days of consuming the respective diet, lambs were administered either saline solution or ACTH (100 IU) twice daily for 3 consecutive days. Administration of ACTH increased serum cortisol and insulin concentrations; however, no effects were seen for serum glucagon concentration. Compared with saline administration, ACTH administration significantly (P less than 0.05) suppressed mitogen-stimulated lymphocyte blastogenesis by approximately 50%, regardless of the mitogen used, and significantly (P less than 0.01) decreased the percentage of circulating T lymphocytes and decreased (P less than 0.01) the ratio of T4 to T8 cells. Lambs fed KIC had greater PHA- and conA-stimulated blastogenic responses and significantly (P less than 0.05) increased ratio of T4 to T8 cells in the blood, compared with lambs fed the leucine-supplemented diet or the control diet and given corresponding injections. These data indicate that ACTH decreased in vitro lymphocyte blastogenesis and altered the subset ratios of blood lymphocytes in sheep. These changes were partially prevented by feeding KIC.
Adrenocorticotropic Hormone↗
Analysis of beta-hydroxy-beta-methyl butyrate in plasma by gas chromatography and mass spectrometry.
A method for measuring the branched chain hydroxy acid beta-hydroxy-beta-methyl butyrate (HMB, a product of leucine catabolism) has been described. A [2H6]HMB internal standard was added to plasma and standards, and samples were extracted with diethyl ether, backextracted into neutral phosphate, dried, and derivatized for gas chromatography and mass spectrometry. The natural HMB was monitored at 175 amu and the deuterated HMB was monitored at 181 amu. Standard curves were linear to at least 25 microns and were quantitatively recovered from plasma. Basal concentrations of plasma HMB were from 1 to 2 microM in sheep and increased three- to fourfold when leucine's alpha-ketoacid (alpha-ketoisocaproate, KIC) was fed to lambs. This method can also be adapted to quantitate KIC and other branched chain ketoacids in plasma during the same run.
Animals↗
The extension technique: a new method of demonstrating initial lymph vessels in excised human skin.
The initial lymph vessels, the lymph capillaries and precollectors, are difficult to detect in normal skin using routine histological methods. A method is described in which specimens of the skin are fixed in an expanded condition. In 1.05 microns thick plastic-embedded sections the dilated lymph vessels of the skin can be demonstrated. The dermal lymph vessel network can be seen following the subepidermal injection of a coloured solution. The endothelial cells and subendothelial fibrous network can be examined using electron microscopy.
Histological Techniques↗
[The extension technic--a new method for in vitro imaging of the initial lymphatic system of the skin in the human].
A technique for detecting initial lymphatics in excised human skin is reported. Excidates are carefully stretched. By subepidermal injection of a Berlin blue solution, dermal lymphatic networks can be imaged. The initial lymphatics can be clearly detected by light microscopy in semi-thin sections.
Ferrocyanides↗
Infusion of nicotinic acid stimulates leucine oxidation and inhibits protein synthesis in pigs before and during a meal.
Leucine metabolism was measured isotopically in immature female pigs to assess the effect of acute infusions of nicotinic acid (NA) on leucine kinetics in both the fed and fasting states. After an overnight fast, immature pigs were infused with 3H-alpha-ketoisocaproate (KIC) and 14C-leucine. After a 2-hour equilibration period, an infusion of either saline or 0.4 mg/kg.min of NA was begun. NA caused a decrease in plasma glucose and an increase in plasma glucagon. During the fasting period, NA increased KIC oxidation 2-fold over controls. After feeding, plasma free fatty acids (FFA) in both groups were equivalent, but KIC oxidation was still approximately 80% higher in NA-infused animals. In addition, NA stimulated proteolysis and inhibited protein synthesis during the meal. Because plasma FFA concentrations were equal during the fed period, it is unlikely that changes in FFA concentrations are responsible for the changes in leucine metabolism observal during NA infusion.
Animals↗
Effects of dietary leucine, alpha-ketoisocaproate and isovalerate on antibody production and lymphocyte blastogenesis in growing lambs.
The chronic effects of oral leucine and leucine metabolites on sheep immune function were determined in two experiments. In replicate experiments, 30 mixed-breed ram lambs were individually fed diets supplemented with approximately 0.05% ruminally protected limestone (control), alpha-ketoisocaproate (KIC), isovalerate (IVA) or leucine (Leu). Serum titers of antibodies produced in response to Brucella abortus antigen and porcine red blood cells were determined. Mitogen-stimulated lymphocyte blastogenesis was determined in experiment 2 by adding phytohemagglutinin (PHA), concanavalin A (Con A) or pokeweed mitogen (PWM) to isolated lymphocytes and measuring [3H]thymidine incorporation. In both experiments, in lambs fed Leu, antibody production to porcine red blood cells was approximately 80% (P less than 0.05) of that in control animals. When KIC was fed, antibody titers to porcine red blood cells were approximately 120% (P less than 0.05) of that of controls. Compared to controls background lymphocyte blastogenesis was higher when KIC was fed, whereas background blastogenesis was lower when Leu was fed (KIC vs. Leu; P less than 0.05). IVA did not significantly affect either measurement. These data indicate that feeding Leu may adversely affect immune function by suppressing lymphocyte activity, whereas oral administration of KIC has a positive influence on immune function in sheep by increasing lymphocyte activity.
Animals↗
Effect of hyperglucagonemia on whole-body leucine metabolism in immature pigs before and during a meal.
Leucine metabolism was measured isotopically in 12 immature female pigs to assess the effect of acute hyperglucagonemia on leucine kinetics in both the fed and fasting states. After an overnight fast, immature pigs were infused with alpha-[3H]ketoisocaproate and [14C]leucine. After a 2-h equilibration period, an infusion of either saline or 7 pg.kg-1.min-1 of glucagon was begun, which increased plasma glucagon from approximately 140 to approximately 640 pg/ml and doubled the insulin concentrations. Two hours later, pigs were fed small meals to which [5,5,5-2H3]leucine was added to trace absorption. By subtracting absorption from total leucine flux, an estimate of endogenous proteolysis during the meal was made. In the fasting state, glucagon increased proteolysis, relative to controls, by approximately 20% (P less than 0.05) and increased oxidation by approximately 50% (P less than 0.05). No significant glucagon-related changes in any other flux parameters occurred in the fasting state. Ingestion of the meals caused oxidation to increase 41% in control animals, whereas in glucagon-infused animals, oxidation increased 84% (P less than 0.05 control vs. glucagon response to meal). Additionally, animals infused with glucagon suppressed endogenous proteolysis 43% after the meal compared with a 55% decrease in control animals (P less than 0.05 basal period vs. fed period). These data indicate that glucagon stimulates whole-body proteolysis in both the fasting and fed states.
Animals↗
Infusion and sampling site effects on two-pool model estimates of leucine metabolism.
To assess the effect of site of isotope infusion on estimates of leucine metabolism infusions of alpha-[4,5-3H]ketoisocaproate (KIC) and [U-14C]leucine were made into the left or right ventricles of sheep and pigs. Blood was sampled from the opposite ventricle. In both species, left ventricular infusions resulted in significantly lower specific radioactivities (SA) of [14C]leucine and [3H]KIC. [14C]KIC SA was found to be insensitive to infusion and sampling sites. [14C]KIC was in addition found to be equal to the SA of [14C]leucine only during the left heart infusions. Therefore [14C]KIC SA was used as the only estimate for [14C]SA in the equations for the two-pool model. This model eliminated the influence of site of infusion and blood sampling on the estimates for leucine entry and reduced the impact on the estimates for proteolysis and oxidation. This two-pool model could not compensate for the underestimation of transamination reactions occurring during the traditional venous isotope infusion and arterial blood sampling.
Animals↗
Milk production and composition in cows and goats fed alpha-ketoisocaproate.
To examine whether alpha-ketoisocaproate supplementation affects milk production, 10 goats were fed either 0 or 1.1% calcium-alpha-ketoisocaproate for 2 wk and 12 cows were fed either 0 or .75% Na alpha-ketoisocaproate for 3 wk. Supplementation with alpha-ketoisocaproate increased milk fat content, milk fat yield, and 4% FCM yield in cows by an average of 5, 10, and 8%, respectively, for the treatment period. In cows, response of milk fat yield to alpha-ketoisocaproate was 120 g during wk 1 of treatment but diminished to 55 g by wk 3. Milk yield and milk protein yield tended to be greater in cows fed alpha-ketoisocaproate, but milk production efficiency and body weight were not altered by treatment in either species. Supplementation with alpha-ketoisocaproate had no significant effect on fatty acid composition of milk but tended to increase the percentage of C10 and C12 fatty acids. In goats, supplementation with alpha-ketoisocaproate had no significant effect on milk production or composition, but trends toward increased milk fat and protein content were observed. Results indicate that alpha-ketoisocaproate acutely stimulates milk fat production in lactating cows and that this effect seems to diminish with time.
Animals↗
[Examining the initial lymph vessels of the guinea pig ear using an extension technic].
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Animals↗
Comparison of growth, exogenous auxin sensitivity, and endogenous indole-3-acetic acid content in roots of Hordeum vulgare L. and an agravitropic mutant.
The chemically induced barley (Hordeum vulgare L.) mutation, agr, was found to be a simple recessive trait resulting in agravitropic roots and normal gravitropic shoots. The total seedling root growth was similar for mutant and wild-type roots, although the mutant had fewer roots per seed and greater elongation per root. Although the concentration of exogenous indole-3-acetic acid (IAA) required to reduce root growth by 50% (GR50) was 12 times greater for the agravitropic mutant, agravitropic and gravitropic roots were equally sensitive to exogenous applications of 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA). Root IAA contents, determined by high-pressure liquid chromatography (HPLC), were not different for gravitropes and agravitropes. The greater root elongation rates, lack of sensitivity to exogenous IAA, and normal endogenous IAA levels indicate that auxin-controlled growth regulation may be altered in the mutant.
2,4-Dichlorophenoxyacetic Acid↗