Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The theoretical background for a conservative therapeutic treatment of uremia is described, with illustrative results from preliminary clinical trials in 10 patients and 10 normal reference subjects. The proposed treatment focuses upon the patient's gastrointestinal tract--the normal site for metabolism of both exogenous (dietary) and endogenous (recycled) protein--enabling it to behave like the rumen of the cow. The objective is to induce the uremic's organism to utilize its own "waste" substances. The patient swallows enterosoluble capsules containing specifically adapted enzymes (immobilized or free) from apathogenic soil microorganisms. These are pre-adapted to convert urea, creatinine, uric acid, guanidino derivatives, and other nonprotein nitrogen compounds (NPN). The enzymes utilize many other substances, in particular ammonia, potassium, phosphorus, and several other factors potentially dangerous for the uremic. The enzymes apparently cleave vasoconstrictatory peptides in the intestines. In the course of the therapy, renoparenchymal hypertension decreased significantly, and increased again when the regimen was interrupted. The results from the present studies are in full accord with the information published in the relevant fields. The time appears ripe for large-scale trials of the therapeutic regimen outlined, especially as many commercial microbial enzymes already have a long history of safe use in food processing.
 ...
PMID:Bacterial enzymes in uremia management. 27 91

Twelve infants with severe perinatal asphyxia were found to have elevated blood ammonia levels (302 to 960 microgram/100 ml). In the seven survivors, hyperammonemia was associated with CNS irritability, hyperthermia, hypertension, and wide neonatal heart rate oscillations. Follow-up examinations revealed severe neurologic dysfunction in five of seven infants. CNS depression, hyperthermia, hypertension, and a nonreactive, fixed heart rate characterized the infants that died. These findings suggest a clinical entity secondary to perinatal asphyxia whose signs and symptoms may be related to hyperammonemia.
 ...
PMID:Hyperammonemia associated with perinatal asphyxia. 48 80

In order to study if rapid elevation of blood pressure is associated with cerebral ischemia, anesthetized (70% N2O) and artificially ventilated rats were subjected to angiotensin-induced hypertension. After a 5 min hypertensive period, cerebral cortex tissue was frozen in situ for subsequent measurements of labile glycolytic metabolites, ammonia, and organic phosphates. The degree of hypertension induced, which gave evidence of blood-brain barrier damage in 7 of 8 rats, did not affect the tissue concentrations of labile metabolites. It is concluded that ischemia does not contribute to the barrier damage, nor is it likely to be the cause of the clinical symptoms that may occur in conscious rats in the same experimental model.
 ...
PMID:Brain energy metabolism in angiotensin-induced acute hypertension in rats. 88 9

Cerebral biopsies were obtained for electron microscopy 48 and 72 hours after the onset of encephalopathy from a child with severe Reye's syndrome. Gravely ill at the time of craniectomy to relieve cerebral hypertension, the child survived and recovered good brain function; therefore, the biopsy findings appear to reflect the organelle pathology of the brain at a severe yet reversible stage in the disease process. The cardinal ultrastructural changes in the brain in Reye's syndrome are astrocyte swelling and partial deglycogenation, myelin bleb formation and universal injury of neuron mitochondria. The mitochondrial injury consists of matrix disruption with moderate but not massive swelling. Dilatation of rough endoplasmic reticulum and nuclear changes occurred only in neurons with severely altered mitochondria. The organelle pathology of the brain in this case did not resemble the organelle pathology of the brain in human "hepatic encephalopathy" or in experimental ammonia intoxication in primates. The mitochondrial ultrastructure of the cerebral neurons resembled the unique mitochondrial ultrastructural changes seen in the liver parenchyma in Reye's syndrome.
 ...
PMID:Brain ultrastructure in Reye's syndrome. 117 96

The pathogenesis of brain edema in acute liver failure is poorly understood. We have previously shown that rats with ischemic acute liver failure (portacaval anastomosis followed by hepatic artery ligation) exhibit brain edema and intracranial hypertension, with swelling of cortical astrocytes as the most prominent neuropathological abnormality. Because ammonia has been shown to induce swelling of astrocytes in vivo and in vitro, we examined the relationship between brain ammonia, amino acids generated from ammonia metabolism and brain water content in this model. Four groups of animals were studied: rats subjected to two sham operations, rats subjected to portacaval anastomosis and a sham operation, rats subjected to a sham operation and hepatic artery ligation and rats subjected to portacaval anastomosis and hepatic artery ligation. The last group of animals was studied at three progressive stages of encephalopathy. Cortical gray matter water increased from 80.26% +/- 0.22% (sham + sham) to 82.46% +/- 0.06% (last stage of devascularization). In cerebral cortex, brain ammonia increased to a maximum of 5.4 mmol/L. Glutamine, generated in glial cells from ammonia and glutamate, increased sixfold to 24 mmol/L and remained at this level throughout all stages of encephalopathy. Alanine, which may be generated from the transamination of glutamine, increased in parallel to the increase in water (r = 0.80, n = 15). In this model of fulminant liver failure and associated brain edema, brain ammonia increases to levels associated with in vitro swelling of brain slices and glial cells. The accumulation of osmogenic aminoacids such as glutamine and alanine may contribute to the selective astrocyte swelling seen in this condition.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Ammonia and related amino acids in the pathogenesis of brain edema in acute ischemic liver failure in rats. 154 26

Chronic diseases of the kidney are characterized by progression once a certain portion of renal function is lost. End-stage kidneys, the result of progressive chronic renal disease, are characterized by sclerosis, tubulointerstitial scarring, and collapse of glomerular capillary tufts. The mechanisms and risk factors responsible for the progression of renal disease have been studied intensively in the past decade, and it now appears that multiple nonimmunologic factors are responsible. These factors include systemic hypertension, hyperlipidemia, proteinuria, excessive intake of protein, and adaptive changes in nephron function as a consequence of nephron loss. The latter adaptations, increased intraglomerular pressure, increased excretion of ammonia, "hypermetabolism," decreased afferent arteriolar tone, and renal hypertrophy, may also be responsible for the progression of renal disease. A complete understanding of the factors responsible for the progression of renal disease should permit rational development of appropriate therapeutic interventions.
 ...
PMID:Progression of chronic renal disease. 213 99

Hyperammonemia is a constant finding following portacaval anastomosis (PCA), and has been incriminated in the neurologic deterioration observed following portasystemic shunt in humans. We developed a rat model for mesenteric venous hypertension by modification of a commonly used technique for studying extrahepatic portal hypertension. We then examined serum ammonia levels in rats undergoing sham operation, mesenteric vein stenosis (MVS) alone, PCA alone, and MVS plus PCA. All MVS animals had a significant (p less than 0.05) elevation in mesenteric venous pressures 2-3 weeks after operation. Serum ammonia levels were normal in rats undergoing sham operation and MVS, and were significantly elevated (p less than 0.001) in rats with PCA. However, a significant (p less than 0.01) reduction in serum ammonia levels was realized when PCA and MVS were combined. These data suggest that intestinal ammonia absorption is a function of splanchnic venous pressure. These findings may be relevant to the management of the neuropsychiatric deterioration seen following PCA in man.
 ...
PMID:Mesenteric venous stenosis reduces hyperammonemia in the portacaval-shunted rat. 226 52

This paper reviews experimental findings which support the concept that vasopressin (VP) and the process of urine concentration may be involved in the progression of chronic renal failure (CRF). The influence of dietary protein intake on the progression of CRF may also involve VP and the operation of the concentrating process. VP receptors have been identified in glomeruli and VP is able to constrict mesangial cells as does angiotensin II. Acute VP infusion increases the glomerular transcapillary hydraulic pressure difference, and chronic VP infusion increases GFR. In rats with CRF (induced by 5/6 nephrectomy), VP levels were found elevated. In rats with 5/6 nephrectomy, we increased experimentally water intake in order to decrease circulating VP levels, urine concentration, and free water reabsorption. Several indices of progression of CRF, including proteinuria, hypertension and glomerulosclerosis, were significantly reduced, thus suggesting a contribution of VP in progression. Lowering protein intake in CRF could be beneficial because proteins, but not carbohydrates or lipids, produce metabolic end products (mainly urea, ammonia, protons, etc.) that are excreted by the kidney, and concentrated in the urine. In healthy subjects (man or rat), high protein (HP) intake favors urine concentration and causes changes in kidney function and morphology very similar to those induced by chronic VP infusion or water restriction. These changes involve an increase in transport activity of the thick ascending limb (where the initial active step of the concentrating process takes place) and may affect filtration rate and/or glomerular hemodynamics secondarily, by decreasing salt concentration at the macula densa and depressing tubuloglomerular feedback.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Possible involvement of vasopressin and urine concentrating process in the progression of chronic renal failure. 270

Hepatic dysfunction after portacaval shunting (PCS) has been attributed to loss of portal perfusion to the liver. Proponents of selective systemic shunting state that reduced encephalopathy and hepatic dysfunction with this procedure result from the maintenance of portal perfusion to the liver through the hypertensive mesenteric venous circulation. We questioned the importance of maintaining the diminished portal flow to the cirrhotic liver because hepatofugal flow is known to develop in many of these patients. We sought to further define mechanisms that may contribute to the maintenance of critical flow to the liver in compensated hepatic cirrhosis. We demonstrated a primary relationship between mesenteric venous hypertension (MVH) and increased hepatic arterial blood flow after diversion of portal blood flow. Fifteen dogs had vena caval stenosis above an end-to-side PCS to establish MVH and deprive the liver of portal blood flow. Another 15 dogs had end-to-side PCS alone. A half hour after shunting, hepatic arterial blood flow had increased significantly in all dogs. Hemodynamic parameters remained stable throughout. Six weeks later, mesenteric pressure increased 98% +/- 3% with intracaval stenosis (from 9.6 +/- 0.1 to 19.0 +/- 0.3 cm H2O). Mesenteric pressure was unchanged with PCS alone (9.0 +/- 0.1 cm H2O). Increased hepatic arterial flow was significantly elevated in all dogs above pre-shunt values by 6 weeks postshunt. With MVH, however, further augmentation in hepatic arterial flow was noted in the chronic state (1.5 +/- 0.1 vs 0.9 +/- 0.1 ml/min/gm, p less than 0.05). There was significant correlation between MVH and increased hepatic arterial flow in the chronic state (r = 0.79, p = 0.05). Hepatic arterial flow 6 weeks after PCS with MVH was associated with lower blood ammonia and improved hepatocellular function compared with animals with PCS alone. These results support the hypothesis that MVH is important in maintaining blood supply--beyond providing driving force for sustained portal flow to the liver. This is an important consideration in the medical and surgical management of portal hypertension, a condition in which profound reduction in portal pressure may negatively affect compensatory hepatic arterial blood flow.
 ...
PMID:Mesenteric venous hypertension: importance after portal systemic shunting? 274 Sep 86

The study was carried out on 23 samples of amniotic fluid taken between 35th and 39th week of pregnancy from 23 pregnant women with arterial hypertension (13 cases of hypertension induced by pregnancy, 5 cases of primary hypertension and 5 cases of hypertension accompanying renal diseases). Seven women undergoing the study gave birth to newborns with symptoms of delayed intrauterine growth below 10 centile (group examined), 16 mothers gave birth to eutrophic babies (control group). In the amniotic fluid of the group examined, bilirubin revealed a significantly higher level. The authors found no changes in the concentrations of ammonia, ions H+ and HPL between the group examined and the control group whereas they were able to observe a significantly lower level of glucose and oestrogens in the amniotic fluid in case of delayed intrauterine foetal growth.
 ...
PMID:[Biochemical examinations of amniotic fluid in arterial hypertension and delayed intrauterine fetal growth. II. Glucose, bilirubin, ammonia, hydrogen ions, estrogens and lactogenic hormone]. 280 77


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