PubMed Health⌕ Search

Biomedical subjects

M Trop

Publications and source records attributed to M Trop.

At least 55 records · Page 3Linked to original sources
PubMed1977

Inactivation of bacterial D-amino acid transaminase by beta-chloro-D-alanine.

Purified D-amino acid transaminase from Bacillus sphaericus catalyzes an alpha,beta elimination from the D isomer of beta-chloroalanine to yield equivalent amounts of pyruvate, chloride, and ammonia; the L isomer of chloroalanine is not a substrate for this transaminase. During the beta elimination there is a synchronous loss in enzyme activity; the Kinact for beta-chloroalanine was estimated to be about 10 micrometers. The alpha-aminoacrylate-Schiff base intermediate formed after beta elimination of chloride ion is probably the key intermediate that partitions between one inactivation event for every 1500 turnovers. In the presence of D-alanine and alpha-ketoglutarate, which are good substrates for the transaminase activity of this enzyme, beta-chloroalanine is a potent, competitive inhibitor (K1 = 10 micrometers) with D-alanine and a weak, uncompetitive inhibitor with alpha-ketoglutarate.

Alanine↗
PubMed1970

The specificity of proteinases from Streptomyces griseus (pronase).

Purification of pronase by ion-exchange chromatography gave four proteolytically active fractions. Fraction A(2) contained an endopeptidase that attacks poly l-valine. Fraction B contained an endopeptidase, an aminopeptidase and carboxypeptidases. The activities against hippuryl-l-arginine and hippuryl-l-phenylalanine could be inhibited to a considerable extent by di-isopropyl phosphorofluoridate and by EDTA. Fraction C contained an endopeptidase resembling bovine trypsin. The pure enzyme was completely inactivated by di-isopropyl phosphorofluoridate and pancreatic trypsin inhibitor and to about 90% by other naturally occurring trypsin inhibitors. Fraction D contained an apparently homogeneous endopeptidase, inhibited by diisopropyl phosphorofluoridate, that adsorbed to and hydrolysed elastin. The activity of all these fractions was tested qualitatively against a wide range of small peptides and synthetic substrates.

Aminopeptidases↗
PubMed1970

Antigenicity of proteinases from Streptomyces griseus (pronase).

The five pronase fractions, A(1), A(2), B, C (trypsin-like), and D (elastolytic), obtained by ion-exchange chromatography, were found to be antigenically distinct. Antibodies to pronase inhibited the enzymic activity of each of the enzyme fractions. Pronase trypsin and bovine trypsin, although resembling each other in enzymic activity and in amino acid sequence around their active sites, did not cross-react antigenically with, nor was their enzymic activity inhibited by, the respective homologous antibodies. Inactivation of pronase trypsin by complexing with soya-bean inhibitor AA, was not associated with a decrease in capacity to precipitate with its antibody. It is assumed that the antigenic sites are located far enough from the catalytic site of the enzyme to allow it to precipitate immunologically even when the catalytic site was blocked.

Amino Acid Sequence↗
PubMedDate not supplied

[Use of continuous arteriovenous hemofiltration in diuretic-resistant hypervolemia and electrolyte disorders].

CAVH was carried out in 10 olig/anuric children with diuretic resistant hypervolemia. In addition, three children had hypercalcemia and one child hypernatremia. All but one needed artificial ventilation for pulmonary edema and positive inotropic cardiac support. Mean duration of CAVH for correction of fluid- and electrolyte imbalance was 51.5 hours (range 20-144 hours). The mean fluid removal of 1715 +/- 1479 (SD) ml decreased mean body weight from 21.4 +/- 18.9 (SD) kg to 19.2 +/- 17.0 (SD) kg. The electrolyte disorders were corrected within 18-24 hours. After correction of fluid overload and electrolyte imbalance 7 children could be extubated and cardiac support could be stopped. Two children died because of multiple organ system failure. CAVH was well tolerated by all children, no hemofiltration related complications occurred. CAVH is an effective and safe extracorporal renal replacement therapy system to correct fluid- and electrolyte imbalances in critically ill children. It can be installed easily and quickly, can be performed in every pediatric intensive care unit and is well tolerated even by small children.

Anuria↗
PubMedDate not supplied

[Incidence and etiologic factors of persistent ductus arteriosus in relation to the severity of idiopathic respiratory distress syndrome].

Out of 332 patients with a confirmed diagnosis of RDS, 214 were mechanically ventilated more than 48 hours and 118 less than 48 hours. The incidence of a hemodynamically active persistent ductus arteriosus (PDA) revealed a significant difference for both groups. (54% versus 4,2%). The distribution of PDA did not seem to correlate with birthweight but rather with the severity of RDS, defined by the duration of artificial ventilation. Between three selected groups of 214 patients with longterm ventilation (1. RDS-PDA with surgical ligation - 2. RDS-PDA with spontaneous closure - 3. RDS without PDA) we found significant differences only in the values of inspiratory pressures on mechanical ventilation. No significant differences were found in the time of exposure to high levels of oxygen, the fluid balance, and the application of furosemide.

Body Weight↗
PubMedDate not supplied

Effect of acute burn trauma on phagocytic activity of the reticuloendothelial system in rats.

The effect of acute burn trauma on phagocytic activity of the reticuloendothelial system measured in vivo with technetium 99m sulfur colloid was examined in rats subjected to acute burn trauma. After the scald injuries (10-second, full-thickness burns) were induced, a reduction in phagocytic activity by the spleen took place with an accompanying increase in the uptake of colloid material by the lungs. Uptake of colloid material by the liver was essentially unchanged. These uptake changes, observed within hours after the inducement of acute burn trauma and apparently continuing for 7 days after burn injury, may explain, in part, the development of septicemia in patients with burns because altered phagocytic activity of the reticuloendothelial system can result in subsequent overabundance of microorganisms and bacteria in the blood.

Animals↗
PubMedDate not supplied

Effect of irreversible dermal necrosis on phagocytic activity of reticuloendothelial system.

A model of full-thickness dermal necrosis was produced in rats by the application of liquid nitrogen to a 20% total body surface area of the dorsal skin surface. In this model there was an alteration of reticuloendothelial system phagocytic activity of the lung and spleen as measured by the uptake of technetium 99m-labeled sulfur colloid in vivo. The present results suggest that marked alterations in reticuloendothelial system phagocytic activity can be produced by full-thickness dermal necrosis in the absence of heat.

Animals↗
PubMedDate not supplied

Core body temperature responses immediately after cutaneous thermal injury in rats.

Internal temperatures were continuously measured in rats that received 20% or 40% body surface area cutaneous scald injuries in 25 degrees C and 38.5 degrees C environments. In animals that received thermal injuries in the 25 degrees C environment, intraperitoneal, intraesophageal, and intrarectal temperatures rapidly rose to 40 degrees C within 5 minutes but returned to normal values within 15 minutes after injury. When 20% body surface area injuries were induced in a 25 degrees C environment, all of the animals survived. In the 25 degrees C environment, neither acute core body temperature elevations nor use of fluid resuscitation predicted survival. In contrast, in a 38.5 degrees C environment core body temperatures rapidly exceeded 41 degrees C with the 20% injury, and all of the animals died within minutes in spite of fluid resuscitation. These studies suggest that the ambient environmental temperature may significantly influence a thermally injured animal's ability to rapidly eliminate absorbed heat of injury and result in an elevated core body temperature, which may contribute to the immediate lethality of the injury.

Animals↗
PubMedDate not supplied

Arterial blood pressure immediately after thermal injury: the role of anesthesia.

Mean arterial blood pressure was measured in anesthetized rats. The duration that the rats were under anesthesia with ether or methohexital was brief, and the animals were allowed to awaken early after injury. Three hemodynamic measurements were compared: (1) lowest mean arterial blood pressure, (2) duration at lowest mean arterial blood pressure, and (3) time to recover initial mean arterial blood pressure. In these studies the anesthetic agents reduced mean arterial blood pressure by 36%, recovering to normal pressures within 24 to 39 minutes. During the hemodynamic observation period, no significant additional hemodynamic effects as a result of the thermal injury were seen. Administration of resuscitation fluid did not significantly affect hemodynamics during the observation period in this study. These studies demonstrate that anesthesia dominates the short-term cardiovascular effects of thermal injury, and therefore caution is required in the interpretation of acute cardiovascular effects immediately after thermal injuries with patients under general anesthesia.

Anesthesia, General↗
PubMedDate not supplied

Continuous arteriovenous hemofiltration in infants.

Renal replacement therapy is sometimes necessary in small infants with acute renal failure or severe metabolic disorders. Of the available methods hemodialysis and peritoneal dialysis are not always feasible in small infants. We used continuous arteriovenous hemofiltration as renal replacement therapy in five small infants. This report describes the technique and efficiency of this new extracorporal treatment modality. Azotemia and hypervolemia can be controlled easily by spontaneous or suction supported arteriovenous hemofiltration. Furthermore it allows adequate parenteral nutrition in anuric infants and eliminates toxic products in amino acid disorders. Arteriovenous hemofiltration is well tolerated by small infants and can be performed in every pediatric intensive care unit.

Acute Kidney Injury↗