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Biomedical subjects

J M Koenig

Publications and source records attributed to J M Koenig.

26 records · Page 2Linked to original sources
PubMed1989

A randomized trial to develop criteria for administering erythrocyte transfusions to anemic preterm infants 1 to 3 months of age.

A randomized trial of erythrocyte transfusion vs no transfusion was performed in 16 preterm infants 1 to 3 months old with hematocrits of less than or equal to 0.29 L/L. To determine which (if any) such patients definitely benefit from transfusion, an analysis of outcome variables was performed. Factors that prospectively identified patients who would benefit from transfusions included a heart rate of greater than 152 beats per minute (P less than .01), apnea/bradycardia (heart rate less than 90/min) requiring intervention to increase the heart rate (P less than .01), and a blood lactate level above the reference range (P less than .02). Additional investigations were performed to determine the cause of the low hematocrits in the study patients. All had diminished, rather than accelerated, erythropoiesis. However, neither the anemia of chronic disorders nor iron deficiency anemia contributed to the diminished erythropoiesis. In all cases, serum erythropoietin levels were below the predicted range (P less than .001). Thus, at least some preterm infants aged 1 to 3 months with hematocrits less than or equal to 0.29 L/L definitely derive benefit from erythrocyte transfusion. The presence of tachycardia, apnea/bradycardia, or an elevated blood lactate may prospectively identify such patients.

Anemia, Neonatal↗
PubMed1988

Role of fibronectin in diagnosing bacterial infection in infancy.

Plasma fibronectin levels and complete blood cell counts were assessed prospectively among 100 infants less than 3 months of age with the provisional diagnosis of "possible sepsis". Seven of the ten infants with culture-proved bacteremia, meningitis, or urinary tract infection had low plasma fibronectin levels as did 12 (13%) of 90 infants with superficial or no documented bacterial infection. The positive predictive value of a low plasma fibronectin level in conjunction with leukocytosis and elevated band ratio for discriminating serious bacterial infection was 71%. Normal white blood cell counts or fibronectin level alone or in combination predicted the absence of serious bacterial infection with an accuracy of at least 94%. Plasma fibronectin determination provides a useful adjunct to the complete blood cell count for the rapid evaluation of extent of illness in young infants with possible sepsis.

Bacterial Infections↗
PubMed1984

Isolation-perfusion of ovine hind limbs. IV. Effects of level of activity on amino acid and glucose metabolism.

Twenty-one wether lambs averaging 30.0 kg were utilized in a study to determine the influence of level of muscular activity (via electrical stimulation) on metabolism of amino acids and glucose of isolated-perfused hind limbs. Treatments consisted of: (1) control, (2) low electrical stimulation and (3) high electrical stimulation. Mean perfusion flow rate was unaffected by treatment or time of perfusion. Perfusion pressure and hematocrit were increased (P less than .05) by stimulation. Glucose levels decreased from a pretreatment average of 44.7 to 41.3, 26.8 and 20.0 mg/dl for treatments 1 to 3, respectively. Lactic acid levels increased from the pretreatment mean of 37.7 to 46.7, 63.8 and 69.4 mg/dl, respectively. Plasma-free fatty acids were utilized from the perfusate at .84, .76 and .68 meq X liter-1 X min-1, respectively. Perfusate urea N levels were unaffected by treatment or time of sampling, but perfusate ammonia levels increased in all treatments (ammonia levels for treatments 1 to 3 increased by .50, 1.09 and 1.47 mg/dl, respectively). Perfusate amino acid changes suggested a flux of some amino acids from muscle to perfusate due to electrical stimulation, but perfusate branched chain amino acid concentrations decreased in all treatment groups. Fifty microcuries of 14C-lysine were included in the initial perfusate. Total perfusate radioactivity in all treatments declined with time, reflective of lysine uptake by the muscle. Total perfusate lysine concentration changed less markedly, suggesting that muscle is contributing to maintenance of plasma amino acid levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1982

Liver arginase activity and urea metabolism in beef heifers fed urea diets and abomasally infused with arginine and(or) ammonium acetate.

Eight growing crossbred beef heifers, surgically fitted with indwelling abomasal cannulas, were used in a 4 x 4 Latin square design and examined for the effects of continuous abomasal infusion of arginine and(or) ammonium acetate on liver arginase activity and urea and ammonia metabolism. Heifers were fed complete diets containing 1.2% urea as the only source of supplemental N. Infusion treatments were: (1) control (C): 2 liters water/24 h; (2) arginine (Arg): 24.00 g arginine in 2 liters water/24 h; (3) ammonium acetate (NH4Ac): 116.34 g ammonium acetate in 2 liters water/24 h; (4) arginine plus ammonium acetate (Arg + NH4Ac): 24.00 g arginine . HCl plus 116.34 g ammonium acetate in 2 liters water/24 h. Infusions solutions contained 0, 1, 1 and 2% crude protein equivalent, respectively, above the level of crude protein provided by the diet. NH4Ac and Arg + NH4Ac increased (P less than .05) apparent digestibility of N over that observed with treatment C. Arg tended to increase N retention over that observed with C, while both NH4Ac and Arg + NH4Ac resulted in lower (P less than .05) N retention than did C and Arg. Mean liver arginase activities (mumol . mg protein-1 . h-1) were 166.9, 137.5, 226.3 and 194.5 for heifers infused with C, Arg, NH4Ac and Arg + NH4Ac, respectively. NH4Ac and Arg + NH4Ac resulted in higher (P less than .05) arginase activity than did C or Arg. Arg infusion increased plasma urea N (PUN) over that observed with C, while PUN was higher (P less than .05) with NH4Ac or Arg + NH4Ac than with C or Arg. NH4Ac infusion increased (P less than .05) plasma ammonia-N (PAN) over that observed with Arg or Arg + NH4Ac, while PAN levels were the same with C, Arg and Arg + NH4Ac. Both Arg and NH4Ac infusion resulted in higher (P less than .05) rumen ammonia levels than C, while heifers given Arg + NH4Ac had rumen ammonia levels similar to those of controls. Mean daily urea excretion was 13.16, 16.02, 28.92 and 32.44 g/24 h for heifers infused with C, Arg, NH4Ac and Arg + NH4Ac, respectively. The major difference in excretion of urea was attributable to NH4Ac and not Arg. Daily urea excretion decreased between 1530 and 2330 h and increased between 2330 and 0730 h. Arginine infusion appeared to have a protective effect against ammonia infusion because PUN increased and PAN decreased in heifers infused with arginine. The reduction (P less than .05) in plasma amino acids thought to be limiting for protein synthesis in ruminants in conjunction with increased (P less than .05) N retention and the trend toward decreased arginase activity observed in heifers infused with Arg suggests that the effects of arginine on ammonia metabolism are not wholly mediated by liver urea synthesis.

Abomasum↗
PubMed1981

Short-term metabolic response in wethers to high dietary protein intake prior to fasting.

Twenty crossbred wether lambs (average body weight 38.9 kg) were examined for selected metabolic responses during fasting as affected by dietary protein level prior to fasting. Animals were fed diet analyzed at 10.4 and 20.3% crude protein (diets A and B, respectively) for 3 weeks and then fasted for 7 days. jugular blood samples were collected 4, 28, 52, 76, 100, 124 and 148 hr after the last feeding. Plasma glucose declined (P less than .05) between 4 and 52 hr, after which no further differences in plasma glucose occurred within or between treatment groups. Plasma urea N (PUN) was higher (P less than .05) in lambs fed diet B at 4, 28, and 52 hr postfeeding. In wethers fed diet A, PUN increased (P less than .05) from 28 to 76 hr postfeeding and then declined to prefasting levels. In wethers fed diet B, PUN did not begin to decrease until 76 hr postfeeding and then gradually declined (P less than .05) until the end of the fast. Plasma ammonia N increased (P less than .05) and plasma albumin decreased (P less than .05) during fasting in both treatment groups, but no differences were observed between the two groups in either parameter. The data support the existence of a "glucose-alanine" cycle in that alanine decreased (P less than .05) in both groups whereas glucose remained constant and PUN increased. Together, these factors suggest enhanced gluconeogenesis from amino acids. Increased branch-chain amino acid oxidation may be responsible for the decrease (P less than .05) in total branched-chain amino acids observed during fasting. The higher dietary protein intake of lambs fed diet B apparently afforded some nutritional advantage, since most of the changes observed occurred approximately 24 hr later in these lambs than in those fed the lower protein diet A before fasting.

Amino Acids↗
PubMed1980

Energy and protein metabolism in ewes as influenced by age and dietary protein-calorie ratio.

A 2 X 2 X 2 fractorial design of treatments was used to study effects of age (20 months or 10 years), dietary energy density (3.0 or 3.5 kcal DE/g) and protein level (8 or 16% crude protein) on energy and nitrogen metabolism in two groups of ewes, with emphasis on efficiency of metabolizable energy utilization. Plasma glucose concentrations were the same for sheep in each age group, regardless of diet; plasma lactate was higher (P less than .03) in plasma of old ewes and decreased (P less than .01) in concentration when dietary energy density was increased. Plasma urea nitrogen was higher (P less than .0001) in ewes fed diets containing 16 vs 8% protein, and plasma ammonia concentrations were higher (P less than .02) in old ewes Dietary energy and protein levels affected digestible and metabolizable energy, but no age-related effects were observed. Nitrogen retention was increased when either energy (P less than .0001) or protein (P less than .003) intake increased. Oxygen consumption was the same for sheep of either age (expressed per kilogram metabolic body weight), while estimated maintenance requirement and heat production were higher for old ewes. Metabolizable energy utilization was lower (P less than .05) in old ewes fed the lower energy density diets than in those fed the higher energy diets. Increasing dietary energy density increased (P less than .05) efficiency of metabolizable energy utilization in old ewes to a level comparable to that observed in young ewes.

Aging↗