Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diminished mucosal mass and a diminished rate of DNA synthesis by the intestinal mucosa have been identified in the rat after thermal injury. Because these changes may be associated with ischemia, the distribution of intestinal blood flow was studied after a thermal injury and compared with the blood flow distribution after hemorrhagic shock. For the thermal injury, anesthetized animals received a standardized 20% body surface area, full-thickness injury and were given intraperitoneal saline resuscitation. By the use of 46Sc- or 141Ce-labeled microspheres, no changes in intestinal and hepatic blood flow occurred after thermal injury. In contrast, a marked redistribution of blood flow was identified after hemorrhagic shock in which a decrease in arterial blood flow was identified to the stomach and to the small and large intestine. Although clinical shock was not present, the cardiac output decreased to a comparable degree in the hemorrhagic shock and the thermal injury. These studies indicate that although physiological changes in intestinal mucosa can be demonstrated after burn injury, these changes are not due to decreases in mesenteric arterial blood flow.
 ...
PMID:Redistribution of blood flow after thermal injury and hemorrhagic shock. 318 40

Endothelial cell dysfunction in ischemia may cause increased capillary permeability. We examined the effect of failing ATP synthesis, a major consequence of ischemia, on microfilaments--important structural determinants of the endothelial cell. Glycolytic and mitochondrial ATP synthesis in bovine pulmonary artery endothelial cells was inhibited by glucose depletion and 650 picomole (pmole) oligomycin/micrograms DNA, respectively. ATP levels were monitored with the luciferase-luciferin assay over a 2-hr time course followed by recovery for 1 hr after removal of the oligomycin and addition of 5.5 mM glucose. ATP levels fell to 83.6 +/- 63.8 pmole/micrograms DNA (n = 11) by 30 min, 26.9 +/- 13.8 pmole/micrograms DNA (n = 11) by 60 min, and 17.2 +/- 3.8 pmole/micrograms DNA (n = 6) by 120 min, whereas control uninjured cells had 541.3 +/- 196.8 pmole/micrograms DNA (n = 6) at 120 min. Fluorescence microscopy of microfilaments stained with rhodamine-phalloidin revealed progressive disassembly and shortening of the microfilaments in greater than 90% of cells over 60 min which correlated with the fall in ATP. Ultrastructural examination revealed that side to side aggregation of microfilaments had occurred over the 120-min time course. Two hours of glucose depletion (305.5 +/- 130.8 pmole ATP/micrograms DNA, n = 6) or oligomycin alone (480.0 +/- 90.1 pmole ATP/micrograms DNA, n = 6) failed to produce the dramatic fall in ATP or the microfilament changes. During cell recovery, there was a rapid reassembly of microfilaments, detected by fluorescence microscopy, which was nearly complete in 85-90% of cells by 45-60 min. ATP levels increased significantly (P = 0.002) to 96.1 +/- 36.8 pmole/micrograms DNA (n = 6) by 30 min. This model should provide insight into the pathogenesis and treatment of the capillary leak seen with ischemia.
 ...
PMID:A cellular model of endothelial cell ischemia. 337 16

Renal damage caused by cyclosporine (CsA) has been documented. Clinical experiences have shown preservation injury further potentiates CsA nephrotoxicity. This study examined the mechanism of nephrotoxicity defined by changes in protein synthesis, DNA synthesis, and ornithine decarboxylase activity in an in vitro model. Initial results showed that CsA inhibited dog kidney epithelium cell (MDCK) replication at a dose of 200 ng after 24 hr (P less than .01) and 100 ng after 48 hr (P less than .01). Protein synthesis was inhibited with 100 ng after 24 and 48 hr (P less than .01). There was a reduction in ODC activity with 200 ng CsA (P less than .05). Methods for simulating transplant-related injuries were then developed. Under ischemic conditions, 18 hr were required before a synergistic effect with CsA produced a reduction in replication (P less than .05). Incubation of MDCK cells in preservative solution at 4 degrees C under hypoxic conditions resulted in a time-dependent reduction in synthetic and replicative capacity that plateaued at 24 hr (P less than .01). The next step was to simulate the clinical situation by combining treatments. MDCK cells were incubated for 24 hr in preservative solution under hypoxic conditions at 4 degrees C, and then CsA was added at defined intervals. The addition of CsA before 24 hr resulted in a significant decrease in cell replication (P less than .05) compared with CsA addition after 48 hr. Similar results were obtained with cells incubated for 48 hr in preservative solution with hypoxia. These data suggest that renal injury from ischemia and cold storage requires a period of cellular repair and replication. Administration of CsA before this period results in further renal injury. Our analysis offers an explanation of CsA nephrotoxicity seen in the human situation and, therefore, may provide a model for studying human nephrotoxicity.
 ...
PMID:An in vitro model for analyzing the nephrotoxicity of cyclosporine and preservation injury. 355 62

Hearts with higher myocardial glycogen levels (MG) have improved tolerance to ischemia. The nutritional status of patients may influence MG levels and so its manipulation may be one way to delay myocardial damage during regional or global ischemia. In this study, the effects of a variety of dietary intakes were examined and correlated with MG levels in rats, grouped and fed in the following manner; Control; rat chow fed ad libitum, fasting of varying periods: 12 hr, 36 hr, 3 days, 5 days, and 7 days, diet manipulation; 4 groups pair-fed equicalorically with rat chow, chow and safflower oil, chow and safflower oil and dextrose, chow and dextrose. Daily weight change was recorded. At sacrifice, MG, myocardial DNA content, liver glycogen (LG), serum free fatty acid (FFA) were measured. It was found that fasting causes rapid elevation of MG within 12 hr, and during fasting the FFA level changes parallel with those of MG. Overall, weight gain had a positive correlation to LG and negative correlation to MG. With diet manipulation, certain substrates (dextrose), although equicaloric, resulted in greater weight gains and higher MG levels. Development of an optimum diet to augment MG and maintain good nutritional condition and to buy more time should be a useful clinical adjunct in patients suffering from unstable angina with high risk of imminent myocardial infarction and for preparing poor risk patients for cardiac surgery.
 ...
PMID:Effects of dietary intake on myocardial glycogen in rats. 376 27

The low-molecular peptide fractions are obtained from the brain of experimental and control animals by the method which includes sedimentation of high-molecular compounds and gel-filtration on Sephadex G-10. Ischemia of the rat brain sharply changes the amino acidic composition of the isolated peptide fractions. An inhibitory effect of the studied fractions on the activity of DNA-dependent RNA polymerase as well as their effect on the heat denaturation of exogenous DNA are established.
 ...
PMID:[Isolation and characteristics of peptide fractions from the rat brain in ischemia]. 407 80

The development of biochemical parameters (cellular DNA and protein) in relation to birth weight was studied in the rabbit, a perinatal brain developer. To induce intrauterine growth retardation and to increase the number of low-birth-weight rabbits, experimental ischemia, in half the fetuses of each doe, was achieved by total ligation of approximately 30% of uteroplacental vessels during the last third of gestation. Following natural delivery, the rabbit pups were raised until 60 days of age, at which time the brains were removed and dissected into cerebral hemispheres, cerebellum and brain stem. The amount of DNA (representing cell number) and protein (suggesting cell size) was estimated in each brain region. A significant correlation was found between low birth weight and reduced DNA in the cerebellum and reduced protein in the cerebral hemispheres. These persistent deficiencies could be related to some lasting handicaps, especially motor incoordination, as an expression of cerebellar dysfunction.
 ...
PMID:Vascular-induced intrauterine growth retardation: relations between birth weight and the development of biochemical parameters in young rabbits. 407 72

In liver cells recovering from reversible ischemia the increase in RNA synthesis by isolated nuclei is preceded by activation of ornithine decarboxylase, leading in turn to an increase in putrescine concentration. Treatment of the animals with 1,3-diaminopropane and putrescine prevents ornithine decarboxylase activation but does not hinder the enhancement of RNA synthesis in post-ischemic liver nuclei; therefore, ornithine decarboxylase activation does not seem to be a necessary prerequisite for the increase in RNA synthesis. Hypophysectomy does not prevent the post-ischemic increases of ornithine decarboxylase and RNA synthesis; but pre-treatment of the animals with cycloheximide--which has a dual effect on the activity of ornithine decarboxylase--abolishes the post-ischemic enhancement of RNA synthesis. In contrast with regenerating liver, changes in ornithine decarboxylase activity and putrescine concentrations in reversible ischemia are not associated to changes in S-adenosylmethionine decarboxylase activity and in spermine and spermidine concentrations that seem to be characteristic of tissues where increases in RNA synthesis are followed by DNA synthesis and cell multiplication.
 ...
PMID:Relationships between polyamine metabolism and RNA synthesis in post-ischemic liver cell repair. 615 62

Both hepatic injury and partial resection are followed by elevation of serum alpha-fetoprotein (AFP). However, whether injured or regenerating hepatocytes are the site of AFP secretion remains controversial. The effects of 3.5 hr of selective hepatic ischemia to the left (L) lobes (70% hepatic mass) of the canine liver on AFP production and liver regeneration by both L and right (R) hepatic lobes are reported. Twenty-one experimental and 13 control animals were studied. AFP was measured by radioimmunoassay in liver tissue homogenates and serum from both systemic and hepatic venous blood obtained preoperatively and on postoperative Days 2, 4, 6, 7, and 8. Tissue AFP was also assessed by immunofluorescent staining. Hepatic regeneration was quantified by autoradiography and DNA specific activity following the intravenous administration of [3H]thymidine. AFP levels were increased above baseline by postoperative Day 4 in biopsies taken from both L and R liver lobes with peak values occurring on Day 7. Immunofluorescent staining confirmed the presence of intracellular AFP in hepatocytes of both R and L lobes on postoperative Days 2 through 6. Serum AFP became significantly elevated above preoperative values by Day 4 and maximal on Day 6. No difference was observed in AFP levels in systemic, L, or R hepatic venous blood. Hepatocellular DNA synthesis was increased on postoperative Days 2 through 8 in both R and L liver lobes. In conclusion, selective hepatic ischemia results in AFP secretion by both injured and uninjured liver lobes. These results suggest that both regenerating and injured hepatocytes synthesize AFP in the dog.
 ...
PMID:Alpha-fetoprotein secretion by injured and regenerating hepatocytes in the dog. 620 10

The cyclic AMP level in epidermis of psoriatic patients was reappraised with a highly sensitive radioimmunoassay method in conjunction with an improved skin biopsy technique to avoid any artificial rise of cyclic AMP due to ischemia. Local intradermal injection before biopsy was avoided, since even saline injection caused a clear-cut ischemia effect. The results concur with our previous study: i.e., on a tissue dry weight or protein basis, the cyclic AMP level in the involved epidermis is 20% higher than that in the uninvolved spidermis of psoriatic patients, and on a DNA basis, there was no significant difference. The cyclic AMP level in normal epidermis from non-psoriatic subjects is the same as that in the uninvolved epidermis of psoriatic patients. Such characteristics in psoriatic lesions as the increased mitosis, incomplete, differentiation and increased glycogen content cannot be simply related to a cyclic AMP deficiency.
 ...
PMID:Epidermal cyclic AMP is not decreased in psoriasis lesions. 624 35

Cyclic GMP levels in epidermis of normal subjects and of psoriatic patients were measured with a highly sensitive radioimmunoassay method. Technical improvements for the assay are 2-fold: (1) skin samples were frozen in vivo before biopsy and local injection of any anesthetic was avoided to overcome ischemia effect which could lower cyclic GMP artificially; (2) epidermis was microdissected to avoid contamination of dermis and keratin layers. The results show that on a per mg tissue dry weight basis the cyclic GMP levels are about 200 fmol in the involved lesional epidermis and 70 fmol in the uninvolved or normal epidermis. Similarly increases in the cyclic GMP levels in the lesional epidermis are observed when the data are expressed either on a DNA or protein basis. The cyclic GMP level in normal epidermis from nonpsoriatic subjects is the same as that in the uninvolved epidermis of psoriasis patients.
 ...
PMID:Epidermal cyclic GMP is increased in psoriasis lesions. 625 90


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