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Biomedical subjects

E Holm

Publications and source records attributed to E Holm.

At least 73 records · Page 4Linked to original sources
PubMed1989

Distribution of some anystid mites (Acari: Anystidae) in Australia and Indonesia and their role as possible predators of the cattle tick, Boophilus microplus (Acari: Ixodidae).

The geographic and habitat distributions of Anystis baccarum, A. jabanica, A. salicinus, and A. sp. B Walzia australica Womersley and Chaussieria warregense in Australia and parts of Indonesia are presented. Laboratory trials showed that A. baccarum will feed upon the larvae of the cattle tick Boophilus microplus, whilst A. jabanica also showed some predatory potential. Walzia australica and C. warregense had no effect on survival of tick larvae.

Animals↗
PubMed1989

Intra- and extracellular amino acid concentrations in portacaval-shunted rabbits. Role of hyperammonemia and effects of branched-chain amino acid-enriched parenteral nutrition.

Intra- and extracellular amino acid concentrations were measured in rabbits in order to elucidate the possible role of hyperammonemia in lowering the postabsorptive plasma levels of branched-chain amino acids (BCAA) and to assess the effects of BCAA-enriched total parenteral nutrition (TPN) on the amino acid pattern of muscle. The pathophysiological part of this paper deals with portacaval anastomosis (PCA) and is aimed at substantiating or rejecting our hypothesis that excessive ammonia-by stimulating glutamine synthesis-reduces the intracellular glutamate pool which is then restored, at least in part, by an intensified BCAA degradation. Regarding infusion therapy, we were mainly interested in whether an amino acid solution adapted to the metabolism in liver cirrhosis causes an accumulation of BCAA in muscle or modifies the intracellular content of glutamate and glutamine. Eighteen rabbits did not undergo surgery and served as controls (group A), while 30 were given a portacaval end-to-side anastomosis (group B). Two weeks after creating the PCA, venous blood samples were taken and muscle biopsies (Bergström's technique) were performed postabsorptively. An 18-h TPN was then started, the regimen administered included dextrose, fat and, in addition, either a conventional (group B1, n = 15) or an adapted amino acid solution (group B2, n = 15). We obtained second blood specimens and muscle biopsies at the end of the infusion period. With the control animals, the same time schedule for blood sampling and muscle biopsies was followed. Fourteen days after the operation, the PCA rabbits displayed a mean plasma ammonia level 5.1 times higher than that measured in the controls (p less than or equal to 0.001). Conventional blood chemistry did not reveal any impairment of liver cell integrity or over-all hepatic function, whereas the nutritional state of the shunted animals worsened, as indicated by body weight and biochemical variables. Since in the PCA rabbits, the total amino acid pools of muscle and plasma were seen to be increased and decreased, respectively, the results concerning the individual amino acids are given in terms of both the absolute and percentage values, the latter more often revealing high levels of statistical significance. PCA induced a marked rise in the intra- and extracellular concentrations of glutamine, while the values of glutamate and alanine showed a decline in muscle and plasma. The extracellular levels of methionine, phenylalanine, and tyrosine were raised, while those of the BCAA were diminished.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1989

Effects of hyperthermia on the peripheral metabolism of ammonia and glutamine.

Although there are a number of physiological states associated with an increase in body temperature, eg, nonseptic and septic fever or exercise, the effects of hyperthermia on intermediary metabolism in vivo have received little attention. The current study was undertaken to examine the peripheral metabolism of ammonia and ammonia-related amino acids using a model of exogenously induced mild hyperthermia in nonfebrile subjects. Arteriovenous levels of metabolites were measured in subjects with known cerebrovascular insufficiency. Peripheral exchange of these metabolites was monitored before, during, and after hyperthermia to an average temperature of 38.5 degrees C. All subjects showed an increase in plasma ammonia and glutamate. There was also an associated peripheral production of ammonia and an uptake of glutamine and alanine by the skeletal muscle tissues. The exchange of glutamate was not affected. These findings indicate that hyperthermia is associated with a nitrogen-sparing effect, the mechanism of which is yet unknown.

Acid-Base Equilibrium↗
PubMed1988

[Conjunctival oxygen pressure in patients with acute cerebral infarct].

Conjunctival oxygen tension and arterial blood gases were measured in 20 patients with acute ischaemic stroke and compared to values obtained in a reference group. The conjunctival capillary bed is perfused by the ophthalmic artery and, thus, reflects the oxygen delivery to the areas supplied by the internal carotid artery. Patients with acute ischaemic stroke showed especially on the ipsilateral side, i.e. the side of the infarction, and to a lesser extent on the other side a lowered conjunctival oxygen tension and a reduced ratio of conjunctival to arterial oxygen tension. These findings indicate disturbances of the blood fluidity, of the cerebrovascular autoregulation and of brain microperfusion. Monitoring of conjunctival oxygen tension is simple and safe. This method allows the assessment of oxygen tension in a tissue bed vascularized by the internal carotid artery. It appears to yield an objective criterion of the effectiveness of therapeutic procedures aiming at an improvement of cerebral perfusion and oxygen supply in patients with acute ischaemic stroke.

Aged↗
PubMed1987

[Intracellular amino acid concentrations in the musculature of 3 species of animals under physiologic, pathophysiologic and infusion therapy conditions].

In the first part of this paper methodological aspects of intracellular amino-acid analysis in three species of animals, i.e. in rats, rabbits, and cats are dealt with. The genetic homogeneity as well as the age of the animal groups, metabolic differences between carnivores and herbivores, the length of the intestine and, thus, the time elapsing before the postabsorptive state is reached, furthermore, the body size which, in studies with muscle biopsies, makes correlated samples either possible or impossible; all these factors are experimental variables potentially affecting the evidence of the results obtained. Amino acids being involved in ammonia detoxification or showing raised plasma levels in hepatic failure form the subject of the subsequent parts of this paper. In the muscle cells of the three above species investigated after an overnight fast, the concentration of glutamine was about 5.5 times and that of glutamate about 4.1 times higher than in human muscle. Regarding glutamine and glutamate, there were no marked differences between the three species. As to the other amino acids measured in the rats, rabbits, and cats, alanine, the branched-chain amino acid (BCAA) as well as methionine and phenylalanine had intracellular values similar to those observed in humans. To test the hypothesis that ammonia lowers the BCAA plasma levels by considerably increasing glutamine synthesis and decreasing the intracellular glutamate pool with consecutively intensified transamination of BCAA for partial replenishment of this pool, we infused ammonium salts and created portocaval shunts in animal experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1986

Structural studies of a carbohydrate-containing immunoglobulin-lambda-light-chain amyloid-fibril protein (AL) of variable subgroup III.

The amino acid sequence of the variable region of a carbohydrate-containing amyloid-fibril protein MOL of immunoglobulin-light-chain type (AL) was elucidated. The sequence determination involved cleaving the protein with CNBr, BNPS-skatole, thermolysin and trypsin. The sequenced protein consisted of about 130 amino acid residues; however, gel-filtration and N-terminal analysis studies revealed AL proteins ranging in Mr from about 10,000 to 25,000. The oligosaccharide chain was found to be bound in the hypervariable region. By sequence homology to other lambda chains the AL protein MOL was shown to be of the V lambda III subgroup.

Aged↗
PubMed1986

[Amino acid uptake and release by colorectal cancer in man].

Little information is available regarding the amino acid exchange by human tumors. To characterize this exchange in vivo, 21 patients with resectable colorectal carcinomas were studied during curative operations. Concerning the amino acid uptake and release by peripheral tissues, 20 non-cancer patients served as controls. Both groups of subjects were well-nourished, as indicated by anthropometric and biochemical variables. In the cancer patients, we cannulated a peripheral artery and vein as well as a central tumor-draining vein and the portal vein. Plasma concentrations and concentration differences were determined in mumol/l and in percentages of the total amino acid amounts. Peripheral glutamate uptake per liter plasma was reduced in the cancer patients (p = 0.02). In these patients, the central tumor-draining vein contained less glutamine (p = 0.002) and more glutamate (p = 0.002) than the peripheral vein. Glutamine uptake by the tumor occurred more often than glutamine release, while glutamate had a negative balance across the tumor in all but three cases. The qualitative differences between the peripheral tissues and the tumors with respect to glutamine and glutamate exchange reached high levels of significance (p = 0.002 for both of the amino acids). In addition, the tumors released more glycine, ornithine, and tyrosine than the periphery. As to glutamine and glutamate metabolism, there was a significant difference between the tumors and the portal-drained organs (p greater than or equal to 0.05). The discussion of the results emphasizes the contributions made by the periphery and the tumor to the plasma amino pattern. The role of glutamine as a potential high importance energy source for neoplastic tissues is delineated.

Aged↗
PubMed1984

Further studies of plutonium and americium at Thule, Greenland.

Eleven years after the accidental loss of nuclear weapons in 1968, the fourth scientific expedition to Thule occurred. The estimated inventory of 1 TBq 239,240Pu in the marine sediments was unchanged when compared with the estimate based on the 1974 data. Plutonium from the accident had moved further away from the impact point and at some locations the vertical distribution indicated a downward displacement of Pu in the sediment column since 1974. Seawater and seaplants showed no evidence of the presence of Pu from sources other than fallout; but Pu in benthos varied nearly proportionally with the levels in sediments. From the measurements of 239,240Pu in the Macoma community since 1970, the transfer factor to this community was estimated at 0.01 Bq a per Bq released to the sediments. The inventory of 241Am was 0.1 TBq. The vertical distribution of Am in sediments did not differ from that of Pu, but in benthos 241Am/239,240Pu were two times higher than in sediments. Seaplants showed the same value of Am/Pu as seawater. There was no indication of any biomagnification of Pu or Am through the marine food chains at Thule.

Americium↗
PubMed1984

Malignant lymphoma of the testis.

Lymphoma presenting in the testis was evaluated in 24 patients. The tumours were classified according to both the Rappaport and the Kiel classification. The Rappaport classification yielded only two tumour types--15 diffuse histiocytic and 9 diffuse mixed histiocytic-lymphocytic, with no pure lymphocytic lymphoma. No difference in survival time was found between these two tumour types. According to the Kiel classification there were four histological tumour types--immunoblastic (11 cases), centroblastic (2), centroblastic/centrocytic (6) and polymorphic immunocytic (5). In comparison with the other tumour types, the centroblastic/centrocytic lymphomas seemed to be advantageous as regards survival. It is concluded that systemic treatment with chemotherapy in accordance with current principles for malignant lymphoma is indicated following orchiectomy in localised testicular lymphoma as well as in disseminated disease. The value of post-operative radiotherapy to regional nodes is questionable.

Adult↗
PubMed1983

[A new micromethod for the determination of ammonia concentrations in whole blood and plasma].

Ammonia concentrations were measured in 152 plasma samples taken from patients with liver cirrhosis or from intensive care patients. For each sample, a new reflectometric procedure (AC-System) as well as the enzymatic method (Monotest) were used. There was a high and significant correlation between the values obtained with the two methods (r = 0.98, p less than or equal to 0.001). Ammonia determination by means of the reflectometric procedure can also be done in whole blood.

Ammonia↗