Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The brain area of female rats three months of age was exposed to 2 krd of X-rays, and various biochemical parameters were retermined as well as NAD(H) in vivo fluorescence of the brain surface after time intervals from one day to 18 months. During the early period, an increase in the uptake of alpha-aminobutyrate (AIB) and a temporary depression in beta-glucuronidase and cathepsin activity followed by an activation at one month was seen. Somewhat later, acid phosphatase increases. During the intermediate period, DNA and serotonin content and AIB uptake by brain increase, whereas AIB uptake by heart and muscle decreases. A fall in sialic acid content is also noted at this time. During the late phase collagen increases, AIB uptake by brain and liver decreases. No changes were found with respect to NAD(H) fluorescence and its response to breathing of low oxygen concentrations.
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PMID:Late effects in the central nervous system. A study of biochemical alterations after local exposure of the rat brain to 2 krd. 18 Jun 35

The effects of an 8-day intravenous infusion of dexamethasone (7.6 mg kg-0.75 body weight) on collagen biosynthesis and wool growth in skin were examined in four Merino wethers. Plasma dexamethasone concentrations reached their peaks during the first 24 h infusion, which were followed by relatively stable levels (c. 1 X 10(-7) M) for the next 4--5 days. Minor increases in plasma dexamethasone levels were recorded during the final 2 days of treatment. Dexamethasone concentrations quickly fell below the level of detection once infusion ceased. Marked decreases in the wet weight, thickness and protein content of skin were observed at the end of infusion. DNA content was reduced to 42.4 +/- 4.9% s.e.m. during the first 2 days of treatment, but in the next 4 days of infusion gradually increased to 85.0 +/0 12.5% of controls. The level of collagen (expressed as hydroxyproline content of its acid hydrolysate) was elevated throughout the infusion and then gradually declined in 3 weeks to about 60% of controls. The biosynthesis of collagen measured by the rate of [14C]hydroxyproline formation and the activity of proline, 2-oxoglutarate dioxygenase (EC 1.14.11.2. formerly prolyl hydroxylase) was reduced during the first half of treatment to a greater extent than the rate of [14C]proline incorporation into proteins. Wool growth was reduced by 80.4 +/- 11.6% in the post-infusion period which allowed three sheep out of four to be defleeced. Inhibition of collagen biosynthesis in sheep skin was due initially to a decrease in the activity of proline, 2-oxoglutarate dioxygenase and later to the reduced rate of proline incorporation into proteins. It was also evident that changes in biosynthetic rate of collagen were not reflected in the total level of skin collagen. The extent of wool growth depression in individual animals paralleled the changes in DNA content and the extent of collagen biosynthesis inhibition.
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PMID:Effect of intravenously infused dexamethasone on collagen metabolism in skin of merino sheep. 23 81

Suspecting that platelet thromboemboli could play a role in the pathogenesis of myocardial ischemia, we did a random-order, double-blind, crossover study of the effect of the platelet aggregation inhibitor, aspirin, on treadmill exercise-induced angina in 13 men with coronary artery disease. Although collagen-induced platelet aggregation and the second phase of adenosine diphosphate (ADP)-induced platelet aggregation were significantly decreased and the rate of disaggregation of ADP-induced platelet aggregates was significantly increased after 650 mg aspirin in buffered solution, there was no delay in onset of exercise-induced angina, change in heart rate-blood pressure product at onset of angina, or change in S-T segment depression at onset of angina. Regardless of whether the patients had received placebo or aspirin on the preceding day, treadmill exercise until angina was followed by no changes in platelet aggregation or disaggregation, platelet count in blood or platelet-rich plasma, or of the plasma concentration of nonesterified fatty acids.
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PMID:Effect of aspirin on exercise-induced angina. 34 92

The main objective of this study was to produce primary acute ischemic injury to myocardium in a live animal. In vitro, guinea pig platelets were sensitive to perturbation and aggregation by a suspension of ultrafine fibrillary collagen material isolated from the aorta of an aged burro (Equus asinus). The platelets responded to the stimulatory action of this material down to 100 to 200 ng (dry weight) added to 0.45 ml of platelet-rich plasma, as determined by aggregometric technique. Aortic fibrillary collagen material injected IV into guinea pigs (350 to 1900 microgram protein/kg of weight) produced a transitory disappearance of virtually all circulating platelets within 5 minutes. In animals in which blood samples were taken 2.5 hours after injection, 50 to 75% of the average base-line platelets in the circulation of controls returned to the circulation. In other experiments, 3 anesthetized animals were injected by jugular vein with an amount of active fibrillary collagen material (300 microgram as protein/kg of animal weight) estimated to produce reversible platelet aggregation in vivo. Two control animals were injected with the same dose of the material that had been inactivated (15 minutes at 100 C) to abolish platelet aggregation. Treated and control animals were maintained under general anesthesia for 2.5 hours. Intraventricular pressures and electrocardiographs (ECG) were monitored continuously for the first 30 minutes. The injection of the active fibrillary collagen material caused a large ventricular pressure elevation (170/10, 180/10, and 150/10 mm of Hg) in approximately 40 s. Preinfusion ventricular pressures in the 3 animals were 65/0, 85/5, and 88/0 mm of Hg, respectively. Within 60 s, there was a reduction in the absolute platelet number in the peripheral circulation. The elevation of ventricular pressure persisted for approximately 5 minutes and was followed within 30 minutes by a set of ECG events suggestive of acute myocardial ischemic injury, which included premature ventricular contractions, transient S-T segment depression concurrent with ventricular hypertension, and S-T segment elevation with reversed tall upright T-waves in association with a decrease to the preinfusion ventricular base line. Other ECG changes included prolongation of the P-R segment, missed ventricular contractions, and arrhythmia. The ECG changes seemed to be subsequent to platelet microthrombus formation in the pulmonary arterial microcirculation. By 2.5 hours after the treatment, platelets "rebounded" into the circulation in 2 surviving guinea pigs, and left ventricular pressures and ECG profiles returned to the preinfusion base lines. Guinea pigs IV infused with similar amounts of inactivated (15 minutes at 100 C) fibrillary collagen material did not show changes.
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PMID:A proposed mechanism(s) of transitory ischemic injury to myocardium. 46 53

Rat brain was exposed to 30, 40 or 60 Gy of roentgen rays and different biochemical and physiologic parameters were assayed from one day to 2 years. The most important changes noted were an intermediate increase in DNA, an intermediate to late--dependent on dose--increase in collagen, a decrease in sialic acid, an early to intermediate increase in serotonin, an increase in cathepsin, an early depression, and intermediate enhancement and a late decrease in alpha amino isobutyrate uptake by brain, and an early reduction, an intermediate--and sometimes late--increase in blood flow. These changes suggest that all three principal systems 2n the brain, nerve cells, glia and vascular system, participate in late changes.
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PMID:Late changes in biochemistry and blood flow in rat brain locally exposed to 30, 40, or 60 Gy. 52 53

Platelet aggregation was investigated in the parents of 4 patients with Bartter's syndrome. Aggregation induced by ADP and ristocetin was normal. However, there was some depression of aggregation induced by collagen. All obligatory heterozygotes showed depressed aggregation in response to epinephrine.
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PMID:Platelet hyporesponsiveness to epinephrine in carriers of Bartter's syndrome. 55 Jan 49

We have devised an improved high pressure liquid chromatographic technique whereby serotonin, nucleosides, cyclic nucleotides, namely cAMP and cGMP, and 5'mono-, 5'di-, and 5'tri-nucleotides can be analyzed. The cyclic nucleotides have been measured in picomolar quantities. All nucleotides can be quantitated in a single step separation in 75 min using a 0.0015 M phosphoric acids vs. 1M pH 4.8 ammonium phosphate gradient. 5/10 ml of platelet-rich plasma furnishes an adequate sample for complete analysis. Nucleotide levels in platelets from 16 normal donors expressed in 10(11) platelets are as follows: cAMP, 6.32 (4.15) nanomoles and AMP, 0.32 (0.14); ADP, 2.48 (0.67); ATP 3.78 (0.68); GDP 0.38 (0.07) and GTP, 0.45 (0.07) micromoles. ADP and ATP values are lower than those previously published. However, the total nucleotide level approaches published values. Upon aggregation with thrombin, approximately 50% of ADP and 40% ATP is releaseed. Release is complete by 2 min. Thrombin is the most potent releasing agent with collagen and ADP occupying an intermediate role and epinephrine being the least effective. Upon aggregation cyclic AMP levels diminish along the other nucleotides. Patients with asthma showed depression of ADP, ATP, GDP and GTP levels.
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PMID:Measurement of nucleotide pools in platelets using high pressure liquid chromatography. 57

Two-stage plastic replicas of fresh and vacuum dried rat tail collagen were examined by electron microscopy. Microphotometer tracings made from the replica micrographs showed that the surface of the collagen has a periodic undulating topography which includes an approximately 20--40 A deep depression located within the major band distance.
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PMID:Surface model of the collagen fibril as determined by two-stage plastic replica. 72 41

Treatment of 24 male patients with 3 g/day of xanthinol nicotinate did not change the in vitro measurements of ADP-induced platelet aggregation but produced a marked inhibition of collagen-induced platelet aggregation. This effect may be connected with the drug-induced depression of the ATP level in platelet-rich plasma. Changes in the platelets in the patients' blood or in the lipid composition and the concentration of uric acid in their serum were ruled out as reasons for the decrease of the collagen-induced aggregation. The activity of the three serum enzymes y-GT, GOT, and GPT and the concentration of the blood sugar did not change.
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PMID:Effect of xanthinol nicotinate treatment on platelet aggregation. 84 33

A large kindred of which multiple members have the Tricho-dento-osseous syndrome is presented. This is an autosomal dominant disorder characterized by defective enamel, taurodontia, unusually curly hair and occasionally mild to moderate skeletal osteosclerosis. Histologic investigation of teeth (by both LM and SEM) demonstrated that there is a uniformly thin enamel covering with randomly distributed depression and pits. The mineral content of this enamel is closer to that of the underlying dentin, which accounts for its lack of radiographic contrast. The dentin was normal. A bizarre finding is that of a periradicular sheath or membrane that enclosed the open apices and extended partway up the root. It was composed of collagen fiber bundles. The anatomical position of this membrane suggested that it may represent the developing peridontal ligament seen in early tooth formation. Recent embryologic evidence provides support for mesenchymal culpability for all reported features of the syndrome.
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PMID:Tricho-dento-osseous syndrome: a scanning electron microscopic analysis. 89 Oct 5


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