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

In 1983, a previously healthy 21-year old mother came to University Hospital in Dijon, France feeling weak and had a severe frontal headache with vomiting. Clinical and biochemical tests were normal. She smoked 20 cigarettes/day and used a high dosed combined oral contraceptive (OC) (ethinyl estradiol and cyproterone acetate). 15 days later, the headache returned and she could not understand spoken words and the bilateral section of the brain had slowed. Yet her mental status was normal as were cerebrospinal fluid and cerebral computerized tomography tests. The antiherpes virus drug, vidabarine, did not alleviate symptoms. At least 1 month later, a severe left pulmonary embolism caused acute right heart failure. She also had a prethrombotic left iliac vein, so physicians began heparin therapy, adding nifedipine and buflomedil to control the spasms in the right internal iliac artery and both external iliac arteries. Acute ischemia of the lower limbs eased within a week but sensory disorders remained for 2 months. Satisfactory collaterality transpired due to a blocked left external iliac artery and left iliac vein. The following signs and symptoms indicated her condition to be homocystinuria: blond hair with deep blue eyes, macrocytic anemia, factor VII deficit (51%), strong positive Brandt's reaction, cystine homocystine in the plasma, and presence of homocystine, cystathionine, and methionine in the urine. Physicians took her off the OC and discharged her on vitamin B6/day, folic acid/day, betaine citrate/day, and the anticoagulant Coumadin. A subsequent check of her 19-year old sister found she had it too. They assessed the patient's condition yearly. In 1988, her left leg developed edema and she limped when not using elastic stockings. Effects of iliac vein phlebitis were evident. She no longer suffered from headaches. Since plasma methionine was within the normal range and homocystine no longer was present in plasma and urine, the physicians halted the anticoagulant therapy. In conclusion, the OC precipitated this partial form of homocystinuria.
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PMID:Vascular manifestations in homocystinuria. 161 Jun 63

Mechanisms for the therapeutic effect of oral contraceptives in dysmenorrhea were studied by recording intrauterine pressure on the first day of menstrual bleeding in women with moderate to severe symptoms and after three weeks of oral contraceptive therapy (150 micrograms levonorgestrel + 30 micrograms ethinyl estradiol, daily). Spontaneous uterine activity and reactivity to intravenous injections of vasopressin (6 pmol/kg body weight; n = 8) or prostaglandin F2 alpha (12 nmol/kg body weight; n = 9) at the two sessions were compared. During the first recording when all women had dysmenorrhea, the uterine activity and reactivity to both agonists were pronounced. After therapy, when the women felt essentially no pain, a statistically significant decrease in spontaneous uterine activity in terms of total pressure area, frequency and amplitude of contractions was observed. The agonist injections induced less pain at the second recording, although the magnitude of responses, superimposed on the much smaller uterine activity at this time, were not significantly different from those at the first recording during dysmenorrhea. The mechanism of pain relief by oral contraception in dysmenorrhea could be a lesser impact of the decreased contractile activity on uterine blood flow, abolishing the local ischemia. A reduced uterine reactivity to agonists might also to some extent contribute to the therapeutic effect.
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PMID:Effect of an oral contraceptive in primary dysmenorrhea--changes in uterine activity and reactivity to agonists. 250 70

A case of mesenteric vascular occlusion is detailed. The 30-year-old female had abdominal pain, bloody diarrhea, and small bowel changes seen on x-ray. She had begun taking the oral contraceptive Ovral (.5 mg norgestrel, .05 mg ethinyl estradiol) 3 years prior to hospital admission. Symptoms began to disappear when her oral contraception was discontinued on the ninth hospital day. Over the next 5 days abdominal signs and symptons subsided progressively. A follow-up small bowel series showed complete disappearance of previous abnormalities. In the differential diagnosis of acute abdominal pain progressing to bloody diarrhea, especially in young women or oral therapy, acute vascular insult with small bowel ischemia must be considered.
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PMID:Reversible mesenteric vascular occlusion associated with oral contraceptives. 470 Oct 37

Severe ischemic lesions were observed in 5 cases among women aged between 35 and 43 years taking the contraceptive pill over a period of 4 years. Three of these patients developed sudden severe ischemia of the lower limbs after the unrecognized appearance of intermittent claudication for periods of from 2 to 10 months, and amputation was necessary after various ineffective treatments. Recovery occurred in the two other patients, one of whom developed ischemia in the upper limb, the other in the lower limb, who were treated at an early stage. The young age of these women and the absence of atheroma were factors that suggested that the oral contraceptives, taken for periods of from 6 months to 4 years, were at least partially responsible for the lesions, and this hypothesis was supported by the discovery of anti-ethinyl estradiol antibodies in the serum. This was probably not the only causative factor, however, as all the patients were smokers. These cases demonstrate the danger of associating smoking with the taking of oral contraceptives, that the latter should be discontinued when signs suggestive of peripheral arterial insufficiency appear, and that urgent thrombectomy should be conducted in cases of severe ischemic lesions.
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PMID:[Acute ischemic lesions in young women taking oral contraceptives. A report on 5 cases (author's transl)]. 724 Sep 88

There are some indications from clinical studies (41,43) for aberrant cyclosporine metabolism resulting in formation of potentially toxic metabolites. When the activity of cytochrome P450 3A enzymes is low, more substrate is available for hypothetical alternative pathways of cyclosporine. There are several reasons for low P450 3A activity in a liver graft such as inter-individual genetic variability (43,49,84), cold ischemia and reperfusion damage, changes of the P450 activity during cholestasis (85) or other liver diseases (86), the influence of cytokines (87) and drug interactions such as inhibition or enzyme induction (88). Furthermore, low concentrations of cytochrome P450 3A influence the cyclosporine blood trough concentrations. The P450 3A concentration as estimated by the erythromycin breath test can be used to calculate the initial cyclosporine dose required to obtain cyclosporine blood trough concentrations in the therapeutic window (89). In vitro such alternative pathways comprising 3-methylcholanthrene-inducible (44,46,47) and/or ethinyl estradiol-inducible cytochrome P450 enzymes (48) could be identified and resulted in production of cyclized cyclosporine metabolites. The exact identification of the P450 enzymes involved requires metabolism of cyclosporine using reconstituted purified enzymes or single P450 enzymes expressed in cell lines. In addition, it remains to be clarified whether cyclosporine itself or its metabolite AM1 is the substrate for cyclization. Because cyclized metabolites have a low affinity to cyclophilin (58,59) they are mainly found in plasma. When more cyclized metabolites are formed primarily the concentration of cyclosporine metabolites in plasma increases. The free fraction of cyclosporine at 37 degrees C was found to be 1%-1.5% (90,91) of the cyclosporine concentration in blood. To date, nothing is known about the free fraction of cyclosporine metabolites. Because distribution characteristics of the cyclized metabolites in blood and urine are different from those of cyclosporine, it can be speculated that the free fraction of the cyclized metabolites is higher than that of cyclosporine. This might be reflected by a higher renal clearance resulting in relatively higher concentrations in urine compared with blood (61; Figure 3). If this is the case, a shift in the metabolite pattern with increased concentrations of cyclized metabolites will lead to an overproportional increase of the free fraction of cyclosporine metabolites. Although it is tempting to assume that cyclization is the alternative pathway explaining cyclosporine toxicity in patients with low concentrations of P450 3A enzymes in the liver (Figure 6), this has not yet been proven and will require not only quantification of P450 3A but of the complete P450 enzyme pattern in the liver in combination with characterization of the cyclosporine metabolite pattern by HPLC with special respect to the cyclized metabolites AM1c and AM1c9. Also, it is still unclear whether or not the cyclized metabolites contribute to cyclosporine toxicity. At least, it is unlikely that they are involved in covalent binding to macromolecules in the liver and kidney (44,71). In a clinical study using an HPLC method which allowed the specific quantification of 16 cyclosporine metabolites it was shown that the blood trough concentrations of the cyclized metabolite AM1c9 is elevated during early nephrotoxicity in liver graft recipients (82) and it was shown in an in vitro model that AM1c9 increases endothelin production and therefore might have a negative effect on renal hemodynamics.(ABSTRACT TRUNCATED)
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PMID:Alternative cyclosporine metabolic pathways and toxicity. 859 1

Estrogen replacement therapy in postmenopausal women is associated with a decreased mortality and morbidity from stroke. The present study was undertaken to investigate the effects of estrogen on endothelial cell glucose transporter 1 (GLUT 1) and on the cell viability during focal ischemia in a rat model. Female rats were ovariectomized (OVX) and 2 weeks later 17beta-estradiol (E2) was injected subcutaneously at a dose of 100 microg/kg 2 h before unilateral middle cerebral artery (MCA) occlusion. Ischemic lesion size was quantified using 2,3,5-triphenyl tetrazolium chloride (TTC) staining and GLUT 1 protein was analyzed by Western blotting. E2 treatment decreased ischemic lesion size in slices taken at 9 and 11 mm posterior from the olfactory bulb by 46.3% and 44.1%, respectively (P < 0.05). GLUT 1 protein decreased in both OVX and E2 groups by 24.6% and 22.7% respectively (P < 0.05) compared with the non-lesioned side in the core ischemic region, including the basal ganglia. GLUT 1 protein was increased in the E2-treated group compared with the control group (23.3%, P < 0.05) in the penumbral ischemic region of the cortex. Primary rat brain capillary endothelial cell (BCEC) cultures were established as an in vitro model for ischemic effects on endothelial cells. Estrogen reduced BCEC loss by 35.9%, 28.4% and 23.5% (P < 0.05) when glucose in the culture medium was reduced to 50%, 20% and 10%, respectively; and by 28.4% and 18.4% (P < 0.05) following 1 or 4 h of anoxia, respectively. This study demonstrates that estrogen treatment increases GLUT 1 transporters and protects BCEC loss which may in turn reduce focal ischemic brain damage.
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PMID:Effects of 17beta-estradiol on glucose transporter 1 expression and endothelial cell survival following focal ischemia in the rats. 941 67

Estrogen administration has a number of favorable cardiovascular effects, and recent evidence suggests that these include an increase in arterial distensibility. Whether this is also the case for the physiological changes in estrogen production during the menstrual cycle has never been determined, however. In 21 premenopausal healthy women, we continuously measured radial artery diameter and blood pressure by an echo-tracking device and a beat-to-beat finger device, respectively. Arterial distensibility was calculated as distensibility/blood pressure curve. The measurements were made during the follicular, ovulatory, and luteal phases of the menstrual cycle. As expected, compared with the follicular phase, plasma estradiol, follicle-stimulating hormone, luteinizing hormone, and prolactin were increased in the ovulatory phase, whereas progesterone was increased in the luteal phase, together with antidiuretic hormone. Radial artery distensibility was increased in the ovulatory and reduced in the luteal phase, the changes being independent of the small, concomitant blood pressure changes. The arterial wall stiffening seen in the luteal phase was associated with a reduction in the flow-dependent endothelial dilatation of the radial artery as assessed by the hyperemia after short-term ischemia of the hand. Thus, the natural menstrual cycle is characterized by alterations in radial artery distensibility. The mechanisms responsible for this phenomenon remain to be clarified. It is possible, however, that the greater arterial distensibility of the ovulatory phase is due to an estrogen-dependent reduction in vascular smooth muscle tone, whereas the arterial stiffening of the luteal phase depends on vascular smooth muscle contraction due to more complex hormonal phenomena, ie, an endothelial impairment due to estrogen reduction but also to an increase in progesterone and antidiuretic hormone levels.
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PMID:Fluctuations of radial artery distensibility throughout the menstrual cycle. 1044 72

We have previously demonstrated the effects of estrogen on modulation of myocardial ATP-sensitive K(+)(K(ATP)) channel. Previous studies have demonstrated that activation of mitochondrial K(ATP)channel is a major contributor of ischemic cardioprotection. The purpose of the present study was to investigate the role of K(ATP)channel in estrogen-induced myocardial protection after ischemia/reperfusion in dogs. Anaesthetized dogs were subjected to 60 min of left anterior descending coronary artery occlusion followed by 2 h of reperfusion. In a first study to characterize effects of sex and the dose-response profile of estrogen on infarct size, the drug was intravenously administered at 10 or 20 microg/kg. In a second study to investigate the cardioprotective mechanisms of estrogen, vehicle, preconditioning or 17 beta -estradiol (10 microg/kg) was given, beginning 15 min prior to the 60 min occlusion period in the presence or absence of 5-hydroxydecanoate (5-HD). In the first study, administration of 17 beta -estradiol resulted in a significant, dose-dependent limitation of infarct size. Estrogen administration provided myocardial protection of similar magnitude in both males and females. In the second study, infarct size in control animals averaged 39+/-5% of the risk region, compared with 14+/-5% of the risk region in estrogen-treated dogs and 6+/-5% of the risk region in preconditioning dogs (both P<0.0001 v controls). Pretreatment with 5-HD completely abolished preconditioning- and estrogen-induced cardioprotection. Estrogen limits myocardial infarction size resulting from coronary artery occlusion and reperfusion in a dose-dependent fashion, irrespective of gender difference. The infarct size-limiting effect of estrogen++ was abolished by 5-HD, suggesting that the cardioprotective effect of estrogen may result from activation of myocardial mitochondrial K(ATP)channels.
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PMID:Cardioprotective effects of 17 beta-estradiol produced by activation ofmitochondrial ATP-sensitive K(+)Channels in canine hearts. 1086 Jul 59

Several clinical studies suggest that estradiol acts as a potent growth and protective factor in the adult brain. Postmenopausal women experience permanent hypoestrogenicity and suffer from increased risk of brain injury associated with neurodegenerative diseases such as stroke and Alzheimer's disease. Estrogen replacement therapy appears to decrease the risk and severity of these neurodegenerative conditions. Studies using animal models have shown that estradiol exerts similar effects in rodents and can enhance cell survival and induce synaptic plasticity. Therefore, we undertook studies to assess whether estradiol treatment can decrease brain injury and cell death induced by an experimental model of ischemia and whether aging animals remain responsive to the protective effects of estradiol. We will review results from recent studies that demonstrate that 1) in young animals, estrogens exert profound protective effects against ischemic brain injury induced by cerebral artery occlusion and 2) the response of aging animals has been tested with varying results. We will discuss and compare our experimental findings that utilize a permanent cerebral artery occlusion model and physiological levels of estradiol replacement therapy in young and middle-aged rats with those of previous studies. These observations provide important insights into the potential protective actions of estrogen replacement therapy on age- and disease-related processes in the brain.
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PMID:Estradiol protects against ischemic brain injury in middle-aged rats. 1099 17

Physical activity and functional capacity have not been assessed by questionnaire for criterion validity in women. We wished to evaluate the ability of a physical activity and a functional capacity assessment questionnaire to predict functional capacity measured by treadmill exercise stress testing, as well as correlate with cardiac risk factors and angiographic coronary artery disease (CAD) in women. In a National Heart, Lung and Blood Institute (NHLBI)-sponsored cross-sectional population study involving four academic medical centers, 476 women with cardiac risk factors undergoing coronary angiography for evaluation for suspected myocardial ischemia were enrolled in the Women's Ischemia Syndrome Evaluation (WISE). The main outcome measures were functional capacity measured during symptom-limited exercise treadmill testing, cardiac risk factors, and CAD, using core laboratory-determined measures. Physical activity measured by the Postmenopausal Estrogen and Progesterone Intervention physical activity questionnaire (PEPI-Q) and functional capacity measured by the Duke Activity Status Index (DASI) questionnaire, correlated with functional capacity measured in metabolic equivalents (METS), as estimated during symptom-limited exercise treadmill testing (r = 0.27, p = 0.001 and r = 0.31, p = 0. 0002, respectively). The DASI was a significant independent predictor of functional capacity even after adjustment for cardiac risk factors, and the PEPI-Q was not. The DASI and PEPI-Q scores were inversely associated with higher numbers and levels of cardiac risk factors, as well as angiographic CAD. The DASI questionnaire is a reasonable correlate of functional capacity achieved during symptom-limited treadmill exercise testing in women with suspected myocardial ischemia. Lower functional capacity or physical activity measured by the DASI and PEPI-Q, respectively, is associated with more prevalent cardiac risk factors and angiographic CAD. These findings suggest that the DASI and, to a lesser extent, the PEPI-Q have criterion validity for use in health-related research in women.
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PMID:Physical activity and functional capacity measurement in women: a report from the NHLBI-sponsored WISE study. 1102 69


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