Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The covalent modification of receptor proteins via phosphorylation and dephosphorylation is one of the principal mechanisms controlling carbohydrate metabolism and is known to be regulated by various protein kinases. Recent studies indicated that many hormones may exert their effects on cellular metabolism by regulating intracellular c-AMP levels and by activating a c-AMP dependent protein kinase, i.e., protein kinase A. The metabolic disturbances during sepsis are characterized by an initial hyperglycemia followed by a progressive hypoglycemia and a depletion of hepatic glycogen content. The latter is coupled with a slowdown in glycogenesis, an accelerated glycogenolysis, and a depression in gluconeogenesis in the liver. Since the liver is the major organ that regulates the homeostatic level of blood glucose, it is conceivable that the sepsis-induced glucose dyshomeostasis might be mediated by changes in protein kinase activity and the kinetic characteristics of enzymes. The present experiment was designed to study the correlation between protein kinase A and the pathophysiology of hepatic glucose dyshomeostasis during sepsis. Sepsis was induced in rats by cecal ligation and puncture (CLP). Late sepsis occurred 18 hours after CLP. Protein kinase A was extracted from the rat livers by acid precipitation and ammonium sulfate fractionation, and then partially purified by DEAE-cellulose. The results show that in the late sepsis, type-I protein kinase A (eluted at low ionic strength) activity was significantly decreased by 34-52% (P < 0.01). The kinetic parameters such as Vmax's for ATP, histone, and c-AMP were also significantly decreased from the control values of 6.1 +/- 0.9, 5.4 +/- 0.8, and 5.1 +/- 1.9 nmoles/mg.min. to 3.6 +/- 0.5, 2.8 +/- 0.3, and 2.5 +/- 0.5 nmoles/mg.min., respectively. Analysis using Hill's equation indicates that the S0.5 and n (Hill coefficient) values of the various substrates and activators for type-I protein kinase A remained unchanged. In the case of type-II protein kinase A (eluted at high ionic strength), the Vmax, S0.5, and n values for ATP, histone, and c-AMP were unchanged during late sepsis. The results of the present study indicate that the activities and kinetic characteristics of type I protein kinase A in rat liver are modified during late sepsis. Since protein kinase A is known to regulate glucose metabolism through adrenergic receptor mediation, these findings may have a pathophysiological significance in the understanding of hepatic glucose dyshomeostasis during sepsis.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:[Kinetic studies of protein kinase A in rat liver during late sepsis]. 129 61

Mechanisms of nutrient alteration of hepatic protein synthesis during sepsis are unclear. In vitro, arginine downregulates endotoxin-stimulated hepatocyte protein synthesis but in vivo effects are unknown. This study evaluated the effects of supplemental arginine or glycine on fibrinogen (acute-phase protein), histone, albumin, and liver protein synthesis after Gram-negative sepsis in the rat. Adult rats (225 g, n = 36) were randomized to receive isonitrogenous isocaloric total parenteral nutrition supplemented with 264 mg of N per kilogram per day as either arginine or glycine. On day 5, each group was further randomized to control or sepsis. Sepsis was induced by injection of 8 x 10(7) Escherichia coli per 100 g body weight, and then a continuous infusion of [1-14C]leucine was started. The rats were sacrificed 4 hours later. The fractional protein synthesis rates (percent per day) of histone, fibrinogen, albumin, and liver were determined. Supplemental arginine led to significantly increased histone (p less than 0.05, analysis of variance) and fibrinogen (p less than 0.01, analysis of variance) synthesis in the septic rats compared with all other groups. Histone and albumin synthesis were also significantly increased (p less than 0.05) in the arginine-supplemented control group compared with the glycine-supplemented control group. Arginine supplementation during sepsis significantly increased (p less than 0.05) albumin and liver protein synthesis compared with controls. Histones which are involved in DNA synthesis and are rich in arginine may play a role in the host response to stress and sepsis. These in vivo results appear to contradict hepatocyte-Kupffer cell coculture studies perhaps because of the hormonal and cytokine responses to nutrient substrate and acute septicemia.
 ...
PMID:Harry M. Vars Research Award. Arginine supplementation improves histone and acute-phase protein synthesis during gram-negative sepsis in the rat. 171 54

Changes in the activities of protein kinase A (PKA, or cAMP-dependent protein kinase) in rat heart during different cardiodynamic phases of sepsis were investigated. Sepsis was induced by cecal ligation and puncture. Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals killed at 9 and 18 h, respectively, after cecal ligation and puncture. Cardiac PKA was extracted and partially purified by acid precipitation, ammonium sulfate fractionation, and DEAE-cellulose chromatography. PKA was eluted from DEAE-cellulose column with a linear NaCl gradient. Two peaks of PKA, type I (eluted at low ionic strength) and type II (eluted at high ionic strength), were collected and their activities were determined based on the rate of incorporation of [gamma-32P]ATP into histone. Results obtained show that during early sepsis, both type I and type II PKA activities were unaffected. During late sepsis, type I PKA activities were stimulated by 66.7-97.7%, while type II PKA activities remained constant. Kinetic analysis of the data on type I PKA during late sepsis reveals that the Vmax values for ATP, cAMP, and histone were increased by 84.7, 66.7, and 97.7%, respectively; while the Km values for ATP, cAMP, and histone were unaltered. These data indicate that type I PKA is activated in rat heart during late hypodynamic phase of sepsis. Since kinase-mediated phosphorylation plays an important role in regulating myocardial function and metabolism, an activation of type I PKA during late sepsis may contribute to the development of altered myocardial function during hypodynamic phase of sepsis.
 ...
PMID:Protein kinase a activity is increased in rat heart during late hypodynamic phase of sepsis. 924 15

Changes in the activities of protein kinase A (PKA) (cAMP-dependent protein kinase) in various regions of rat myocardium during different cardiodynamic phases of sepsis were studied in an attempt to understand the pathophysiology of cardiac dysfunction during sepsis. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 hr, respectively, after CLP. Cardiac PKA was extracted and partially purified by acid precipitation, ammonium sulfate fractionation, and DEAE-cellulose chromatography. PKA was eluted from DEAE-cellulose column with a linear NaCl gradient. Two types of PKA, Type I (eluted at low ionic strength) and Type II (eluted at high ionic strength), were collected, and their activities were determined based on the rate of incorporation of [gamma-32P]ATP into histone. Under physiological conditions, Type I PKA activities were unevenly distributed (left atrium > right atrium > pacemaker region > left ventricle > right ventricle > ventricular septum) while Type II PKA activities were evenly distributed among different regions of myocardium. During early sepsis, Type I PKA activities remained unchanged while Type II PKA activities were activated by 32 and 70% in right atrium and pacemaker regions, respectively. During late sepsis, Type I PKA activities were stimulated by 228% in ventricular septum while Type II PKA activities were not affected. These data demonstrate that different PKA activities exist in various regions of the myocardium and that PKA activities were preferentially activated in certain areas during the progression of sepsis. Since PKA plays an important role in the regulation of myocardial function and metabolism, the activation of PKA in different regions of myocardial during different stages of sepsis may contribute to the altered cardiac function during the progression of sepsis.
 ...
PMID:Differential activation of protein kinase A in various regions of myocardium during sepsis. 929 85

Changes in protein kinase C (PKC) (calcium- and phospholipid-dependent protein kinase) activity in rat heart during different cardiodynamic phases of sepsis were studied in an attempt to understand the pathophysiology of altered myocardial function during sepsis. Sepsis was induced by cecal ligation and puncture. Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 h, respectively, after cecal ligation and puncture. Cardiac PKC was extracted and partially purified by ammonium sulfate fractionation and diethylaminoethyl-cellulose chromatography. PKC activity was assayed on the basis of the rate of incorporation of 32P from [gamma-32P]adenosine triphosphate into histone. The results show that during early sepsis, cytosolic PKC activity was increased by 42-73%, whereas membrane associated PKC activity was unchanged. During late sepsis, both cytosolic and membrane associated PKC activities remained unchanged. Kinetic analysis of the data on cytosolic PKC during the early phase of sepsis reveals that the Vmax (maximal velocity) values for Ca2+, phosphatidylserine, and diacylglycerol were increased by 58, 42, and 50%, respectively, with no changes in their Km (substrate concentration required for half-maximal enzyme activity) values. These data indicate that cytosolic PKC activity was activated in rat heart during the early hyperdynamic phase of sepsis. Because PKC mediated phosphorylation plays an important role in regulating myocardial contractility, an activation in cytosolic PKC may contribute to the development of a hypercardiodynamic state during the early phase of sepsis.
 ...
PMID:Protein kinase C activity is increased in rat heart during the early hyperdynamic phase of sepsis. 952 27

Changes in protein kinase C (PKC) (calcium- and phospholipid-dependent protein kinase) activity in rat liver during different metabolic phases of sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 h, respectively, after CLP. Hepatic PKC was extracted and partially purified by ammonium sulfate fractionation and DEAE-cellulose chromatography. PKC activity was assayed based on the rate of incorporation of 32p from [gamma-32P]ATP into histone. The results show that during early sepsis, both membrane-associated and cytosolic PKC activities remained relatively unaltered. During late sepsis, membrane-associated PKC was unaffected while cytosolic PKC activity was decreased by 19.5-34.4%. Kinetic analysis of the data on cytosolic PKC during late phase of sepsis reveals that the Vmax values for ATP, histone, Ca2+, phosphatidylserine, and diacylglycerol were decreased by 23.4, 22.1, 19.5, 25, and 34.4%, respectively, with no changes in their Km values. These data indicate that cytosolic PKC activity was inactivated in rat liver during late hypoglycemic phase of sepsis. Since PKC-mediated phosphorylation plays an important role in regulating hepatic glucose metabolism, an inactivation of cytosolic PKC may contribute to the development of hypoglycemia during late phase of sepsis.
 ...
PMID:Inactivation of protein kinase C in rat liver during late hypoglycemic phase of sepsis. 956 54

Changes in protein kinase A (PKA, or cAMP-dependent protein kinase) activity in the rat liver during different metabolic phases of sepsis were investigated. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into 3 groups: control, early sepsis, and late sepsis. Early and late sepsis refer to those animals killed at 9 and 18 h, respectively, after CLP. Hepatic PKA was extracted and partially purified by acid precipitation, ammonium sulfate fractionation, and diethylaminoethyl (DEAE)-cellulose chromatography. PKA was eluted from DEAE-cellulose column with a linear NaCl gradient. Two peaks of PKA, type I (eluted at low ionic strength) and type II (eluted at high ionic strength), were collected and their activities were determined on the basis of the rate of incorporation of [gamma-32-P]ATP into histone. The results show that during early sepsis, both type I and type II PKA activities remained unchanged. During late sepsis, type I PKA activity was decreased by 40.7-53.6%, whereas type II PKA activity was unaffected. Kinetic analysis of the data on type I PKA during the late phase of sepsis reveals that the Vmax (maximal velocity) values for ATP, cAMP, and histone were decreased by 40.7, 53.6, and 47.3%, respectively whereas the Km (substrate concentration required for half-maximal enzymatic activity) values for ATP, cAMP, and histone were unaltered. These data indicate that type I PKA was inactivated during the late hypoglycemic phase of sepsis in the rat liver. Because PKA-mediated phosphorylation plays an important role in the regulation of hepatic glucose metabolism, an inactivation of PKA may contribute to the development of hypoglycemia during the late phase of sepsis.
 ...
PMID:Liver protein kinase A activity is decreased during the late hypoglycemic phase of sepsis. 1050 29

Mechanisms of nutrient alteration of hepatic protein synthesis during sepsis are unclear. In vitro, arginine downregulates endotoxin-stimulated hepatocyte protein synthesis but in vivo effects are unknown. This study evaluated the effects of supplemental arginine or glycine on fibrinogen (acute-phase protein), histone, albumin, and liver protein synthesis after Gram-negative sepsis in the rat. Adult rats (225 g, n=36) were randomized to receive isonitrogenous isocaloric total parenteral nutrition supplemented with 264 mg of N per kilogram per day as either arginine or glycine. On day 5, each group was further randomized to control or sepsis. Sepsis was induced by injection of 8 x 10(7) Escherichia coli per 100 g body weight, and then a continuous infusion of [1-14C] leucine was started. The rats were sacrificed 4 hours later. The fractional protein synthesis rates (percent per day) of histone, fibrinogen, albumin, and liver were determined. Supplemental arginine led to significantly increased histone (p < 0.05, analysis of variance) and fibrinogen (p < 0.01, analysis of variance) synthesis in the septic rats compared with all other groups. Histone and albumin synthesis were also significantly increased (p < 0.05) in the arginine-supplemented control group compared with the glycine-supplemented control group. Arginine supplementation during sepsis significantly increased (p < 0.05) albumin and liver protein synthesis compared with controls. Histones which are involved in DNA synthesis and are rich in arginine may play a role in the host response to stress and sepsis. These in vivo results appear to contradict hepatocyte-Kupffer cell coculture studies perhaps because of the hormonal and cytokine responses to nutrient substrate and acute septicemia.
 ...
PMID:Arginine supplementation improves histone and acute-phase protein synthesis during gram-negative sepsis in the rat. 1153 88

The present study investigated the alteration of protein kinase C (PKC) isoforms in rat liver during the progression of sepsis. Cecal ligation and puncture (CLP) model of polymicrobial sepsis was used, with early and late sepsis referring to those animals sacrificed at 9 and 18 h, respectively, after CLP. The protein contents of various PKC isoforms were quantified by Western blot and densitometric analysis. PKCalpha activity was performed after immunoprecipitation and assayed based on the incorporation rate of 32p from [gamma-32p] adenosine triphosphate (ATP) into histone. The distribution of PKCalpha was evaluated by immunohistochemical staining. The steady state expression of PKCalpha mRNA was estimated by reverse transcriptase-polymerase chain reaction (RT-PCR). The results indicated that 1) five isoforms (alpha, beta, delta, epsilon, zeta) could be detected in normal rat liver. PKCalpha and beta were predominantly present in the cytosolic fraction, while membrane-associated PKCdelta was more prominent than that of cytosolic fraction; 2) the protein content of membrane-associated PKCalpha was significantly decreased at early (P < 0.05) and late (P < 0.01) sepsis; 3) there was no significant difference of protein contents of PKC-delta, -epsilon and -zeta between sham-operated and septic rat liver; 4) the activity of membrane-associated PKCalpha was significantly declined under detection level during sepsis; 5) at both early and late sepsis, the immunohistochemical staining of PKCalpha was significantly diminished, especially in the nucleus; 6) the RT-PCR product of PKCalpha mRNA of septic liver was significantly less than the sham-operated liver. These results suggest that inactivation and the suppression of PKC-alpha gene transcription might be involved in modulating hepatic failure during sepsis.
 ...
PMID:Alteration of protein kinase C isoforms in the liver of septic rat. 1179 68

The histone-like protein H-NS is a global regulator in Escherichia coli that has been intensively studied in nonpathogenic strains. However, no comprehensive study on the role of H-NS and its paralogue, StpA, in gene expression in pathogenic E. coli has been carried out so far. Here, we monitored the global effects of H-NS and StpA in a uropathogenic E. coli isolate by using DNA arrays. Expression profiling revealed that more than 500 genes were affected by an hns mutation, whereas no effect of StpA alone was observed. An hns stpA double mutant showed a distinct gene expression pattern that differed in large part from that of the hns single mutant. This suggests a direct interaction between the two paralogues and the existence of distinct regulons of H-NS and an H-NS/StpA heteromeric complex. hns mutation resulted in increased expression of alpha-hemolysin, fimbriae, and iron uptake systems as well as genes involved in stress adaptation. Furthermore, several other putative virulence genes were found to be part of the H-NS regulon. Although the lack of H-NS, either alone or in combination with StpA, has a huge impact on gene expression in pathogenic E. coli strains, its effect on virulence is ambiguous. At a high infection dose, hns mutants trigger more sudden lethality due to their increased acute toxicity in murine urinary tract infection and sepsis models. At a lower infectious dose, however, mutants lacking H-NS are attenuated through their impaired growth rate, which can only partially be compensated for by the higher expression of numerous virulence factors.
 ...
PMID:Role of histone-like proteins H-NS and StpA in expression of virulence determinants of uropathogenic Escherichia coli. 1685 32


1 2 3 4 5 6 7 8 9 10 Next >>