Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: HUMANGGP:031673 (collagen)
 124,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Platelet functions studied in 163 unselected diabetics compared with 163 controls had the following characteristics: hyperagregation induced by ADP (1.2 muM and 0.6 muM), delayed platelet disagregation (ADP: 0.6 muM), normal agregation in the presence of collagen and thrombin. Platelet hyperagregation induced by ADP was marked in both sexes in cases of retinopathy and in women after the age of 50. By contrast, no correlation was demonstrated between the degree of hyperagregation and age, weight, the duration of diabetes, blood glucose control, lipid profile, vascular complications other than retinopathy and the nature of treatment.
 ...
PMID:[Platelet functions in diabetes with angiopathy (author's transl)]. 53 70

Modified Ivy bleeding time (template) and platelet aggregation to ADP, epinephrine, and collagen were studied in 26 uremic patients who had not recently ingested anti-platelet drugs. Regardless of the aggregating agent used, the abnormalities in platelet aggregation were often mild, even with advanced uremia, and frequently less severe than the effects of common anti-platelet drugs. The inhibition of collagen-induced aggregation was significantly correlated with both increased bleeding time and blood urea nitrogen. Platelet aggregation was not discriminative between clinically bleeding and non-bleeding groups of patients, but the bleeding time was helpful in this regard. In certain cases, the aggregometric patterns differed between drug-induced and uremic thrombocytopathies. Platelet aggregometry appears to be of little help clinically in assessing the severity of the uremic bleeding diathesis.
 ...
PMID:Bleeding time in uremia: a useful test to assess clinical bleeding. 53 88

10-Methoxy-1,6-dimethyl-ergoline-8 beta-methanol-(5-bromonicotinate) (nicergoline, Sermion) is introduced into human platelet-rich plasma at different stages of collagen-, ADP- or epinephrine-induced aggregation. Ultrastructural fixation is processed while aggregation on the same plasma sample is recorded. If introduced before the aggregating agent, nicergoline completely neutralises its action and the platelets become spherical. The microtubule marginal bundle is disorganized and both open and dense canalicular systems are modified. If intoduced after the aggregating agent, nicergoline immediately stops the aggregation and disaggregation follows, with complete separation of the platelets. Morphology of microtubules and canalicular systems depend on the time before application of nicergoline. Nicergoline stops the induction of aggregation as well as ADP release. Disaggregation is an active process involving the microtubules.
 ...
PMID:[Ultrastructural study on the effect of an inhibitor of platelet aggregation (author's transl)]. 54 72

Addition of N-acetyl neuraminic acid (sialic acid, NANA) to citrated rat platelet-rich plasma significantly inhibited aggregation induced by near-threshold concentration of ADP, collagen or thrombin. In heparinized rat platelet-rich plasma aggregation of platelets induced by endotoxin or tumour cells of various origins was also inhibited by sialic acid. It is suggested that exogenous or endogenous sialic acid may act against various aggregating stimuli on the platelet membrane by masking a common factor through which various aggregating agents exert their effect.
 ...
PMID:Inhibition by N-acetyl neuraminic (sialic) acid of platelet aggregation induced by different stimuli. 54 28

The hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 microM ADP, were not inhibited by 500 microM adenosine, a concentration that greatly reduced the effect of 300 microM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.
 ...
PMID:Collagen-induced platelet aggregation:--evidence against the essential role of platelet adenosine diphosphate. 54 29

The role of reduced glutathione (GSH) on platelet functions was investigated utilizing thiol oxidizing agent, "diamide". Diamide reacted rapidly with GSH in platelets, but not with protein thiols. Platelets treated with diamide showed inhibition of platelet aggregation induced by ADP, epinephrine and collagen in a concentration dependent manner. Clot retraction was grossly inhibited by diamide. Platelet interaction with polymerizing fibrin was examined by the method of Niewiarowski et al. (1972). There was no interaction obeserved between diamide-treated platelets and polymerizing fibrin. Ultrastructural observation of clots formed in the presence of diamide also showed no direct contact between platelets and fibrin strands. Platelets retained their granular contents, but showed loss of microtubules and dilatation of open canalicular system. Our findings may further support the idea that GSH plays an important role on platelet functions.
 ...
PMID:Role of reduced glutathione on platelet functions. 54 37

Changes in platelets in 48 patients with uterine myoma before and after hysterectomy with and without ovariectomy were examined. Bilateral ovariectomy in 25 cases (ovariectomized group) and unilateral or non-ovariectomy in 23 cases (control group) were performed at the hysterectomy. Platelet count and an appearance rate of secondary aggregation decreased at one day after and increased at one week after the operation, similarly in both the ovariectomized and the control group. The appearance rate of secondary aggregation was reflected in an intensity of aggregation at 5 min after the addition of reagent to PRP. At one month after the operation, the appearance rate of secondary aggregation induced by 3 microM ADP showed a statistically significant decrease in comparison with the preoperation value (P less than 0.05) and the enhancement of 5-min aggregation was still observed in the control group, while ceased in the ovariectomized group. The difference between the two groups was significant (P less than 0.05). There was almost no change in the speed and intensity of primary and secondary aggregation during the observation period. No significant differences in collagen-induced aggregation were noted between the two groups. The results suggest that ovarian hormones, mainly estrogen, facilitate platelet activation which is mediated by the so-called secondary aggregation.
 ...
PMID:Changes in platelet aggregability after ovariectomy. 54 38

Impairment of platelet function is well recognized in the neonate. The abnormalities include a reduction in platelet factor 3 activity and availability, a reduction in the release of nonmetabolic storage pool ADP and ATP, and platelet factor 4 following stimulation, decreased adhesiveness, and impaired aggregation with ADP, epinephrine, collagen, and thrombin. Whether the cause of the platelet abnormality and the impairment in platelet secretion is due to a "storage pool deficiency" or an "aspirin-like defect" has been unclear. However, recent data suggests that the neonatal platelet possesses neither a significant deficiency in prostaglandin synthesis nor a significant decrease in storage pool adenine nucleotides. The abnormalities noted appear most likely to be due to a membrane-related phenomenon.
 ...
PMID:Platelet function in the neonate. 54 16

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.
 ...
PMID:Platelet hyporesponsiveness to epinephrine in carriers of Bartter's syndrome. 55 Jan 49

The alpha-1 acid glycoprotein (orosomucoid; AAG) is a normal constituent of human plasma (650+/-215 microgram ml(-1)) which increases in concentration as much as fivefold in associations with acute inflammation and cancer, and thus is recognized as an acute phase protein. AAG consists of a single polypeptide chain, has a molecular weight of 44,100, and contains approximately 45% carbohydrate including 12% sialic acid; it is the most negatively charged of the plasma proteins. Certain of the biological properties of AAG are related to its sialic acid content; thus, clearance and immunogenicity of AAG are markedly increased on desialisation. The biological functions of AAG are largely unknown. AAG has the ability to inhibit certain lymphocyte re-activities including blastogenesis in response to concanavalin A, phytohaemagglutinin and allogeneic cells, and these inhibitory effects are enhanced in association with desialisation. In view of these observations, a report that unphysiologically large (5--15 mg ml(-1)) amounts of AAG inhibit the platelet aggregation induced by ADP and adrenaline, and evidence that a sialic acid-deficient species of AAG appears elevated in several chronic disease states, we compared the effects of AAG and its desialised counterpart (AAG-D) on platelet aggregation. We report that desialisation of AAG is associated with increased expression of activity inhibitory to the platelet aggregation otherwise observed on stimulation with ADP, collagen or thrombin.
 ...
PMID:Inhibition of platelet aggregation by native and desialised alpha-1 acid glycoprotein. 55 Dec 86


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