Platelet transfusion practice: time for renewed consensus

BACKGROUND: Bilateral tubal pregnancies are rare and are usually confirmed simultaneously during the same operation. We report a case in which the right salpingectomy was performed seven weeks before the left salpingectomy. When the right salpingectomy was done, the left uterine tube appeared entirely normal. CASE: A 38-year-old woman underwent laparoscopic surgery for suspected right tubal pregnancy. A right tubal pregnancy was found to have partially aborted into the peritoneal cavity. The left uterine tube was carefully inspected and appeared normal. Histopathology of the right tube showed products of conception and chorionic tissue. Seven weeks after surgery, the woman presented in hemorrhagic shock necessitating emergency laparotomy and left salpingectomy. Histopathology of the left tube confirmed the presence of chronic tissue. The patient did not have coitus between the two salpingectomies. CONCLUSION: The explanation of the presentation is uncertain. However, this case underscores the importance of careful follow-up of patients after laparoscopic surgery for ectopic pregnancies.     

Platelet production capacity at intervals after acute thrombocytopenia

Platelet producing capacity was examined at intervals after acute platelet depletion by reinduction of acute thrombocytopenia and assessment of the subsequent platelet recovery rates of 35S-sulfate incorporation into platelets. Platelet producing capacity was increased on days 1 and 2, somewhat decreased on days 3 and 4 and had returned to baseline by day 5. These studies suggest that there is an initial increase followed by a decrease on days 3 and 4 in cells which can respond to thrombopoietic stimulating factor after induction of acute thrombocytopenia.     

Quantity food production labor time

To facilitate the development and use of production time data in quantity foodservice, Master Standard Data (MSD) were applied to determine the feasibility of developing a standard code for synthesizing and predetermining production times. Observations were made in a 2,000-meal-per-day foodservice system to determine basic activities common to the production of single-item entrées. An MSD Quantity Food Production Code was developed through the use of MSD and verified by stop-watch time study. Three formulas for single-item entrées were analyzed, divided into basic elements of production, from which production time for preparation of 100 portions of each entrée was synthesized. Stop-watch studies were performed on three replications of the production of 100 portions of each item. Differences between synthesized time values determined by applying the MSD and stop-watch technique were within acceptable limits. The MSD Quantity Food Production Code was, therefore, considered valid and reliable. Repeated occurrence of similar elements within production methods indicated that the code could serve as a structural framework for establishing a universal data code applicable to all aspects of quantity food production.     

Platelet activating factor and thromboxane B2 production after cardiopulmonary bypass

Since its original discovery as the neuroendocrine hormone responsible for inhibiting growth hormone (GH) secretion, our understanding of the functions of somatostatin [or somatotrophin release inhibitory hormone (SRIH)], both in the periphery and the CNS, has grown enormously. With the cloning of five SRIH receptors, much interest has centred recently on the potential use of SRIH analogues in the treatment of clinical conditions ranging from human cancers to Alzheimer's and Parkinson's diseases. There is a growing recognition that the physiological functions of GH also need to be extended beyond its role in growth control, e.g. to a role in the maintenance of normal immune, cardiovascular and reproductive functions. Here, Glenda Gillies addresses the importance of somatostatinergic systems in regulating the sexually dimorphic patterns of GH secretion as well as their influence on other endocrine hormones. She also considers the neurotransmitter/neuromodulator actions of SRIH within the hypothalamus, where it is involved in the neural control and integration of many aspects of endocrine function, as well as its potential role in the maturation of the hypothalamus during the critical perinatal period.     

围手术期抗菌药物合理应用依从性调查分析

目的:对各种因手术而住院的患者在应用抗菌性药物的情况及合理性进行调查分析.方法:对2007年3月到2011年3月在我院就诊的213例手术患者,就抗菌性药物的应用种类、联合用药方式等几方面进行统计学分析.结果:通过加强对围手术期抗菌性药物的用药的管理工作,并制定可行的规章制度结合定期监测及结果反馈等手段,发现我院手术患者的抗菌性药物总使用率以经达到95.98%,其中单独使用、二联、三联及以上的患者百分比分别为45.83%,44.91%,44.86%,9.23%预防性应用达到89.73%,分析认为合理应用抗菌性药物占39.41%,基本合理的应用抗菌性药物占35.62%,其中有23.98%的患者没有合理的使用抗菌性药物.结论:对使用抗菌性药物的患者加强管理,对围手术期抗菌性药物的应用执行规范的使用原则是非常重要的药物的使 用原则非常重要.     

Platelet alpha-granules

Platelets contain a vast number of biologically active molecules within cytoplasmic granules which are classified according to their respective distinct ultrastructures, densities and content. The alpha-granule is a unique secretory organelle in that it exhibits further compartmentalization and acquires its protein content via two distinct mechanisms: (1) biosynthesis predominantly at the megakaryocyte (MK) level (with some vestigial platelet synthesis) (e.g. platelet factor 4) and (2) endocytosis and pinocytosis at both the MK and circulating platelet levels (e.g. fibrinogen (Fg) and IgG). The currently known list of alpha-granular proteins continues to enlarge and includes many adhesive proteins (e.g. Fg, von Willebrand factor (vWf) and thrombospodin (TSP)), plasma proteins (e.g. IgG and albumin), cellular mitogens (e.g. platelet derived growth factor and TGF beta), coagulation factors (e.g. factor V) and protease inhibitors (e.g. alpha 2-macroglobulin and alpha 2-antiplasmin). More recently the inner lining of the alpha-granule unit membrane has been demonstrated to contain a number of physiologically important receptors including glycoprotein IIb/IIIa (alpha IIb beta 3) and P-selectin. The alpha-granules originate from small precursor granules which can be observed budding from the trans-Golgi network within the platelet precursor cell the MK. During MK maturation the alpha-granules become very prominent and are ultimately packaged into platelets during thrombopoiesis. The alpha-granular contents are destined for release during platelet activation at sites of vessel wall injury and thus play an important role in haemostasis, inflammation, ultimate wound repair and in the pathogenesis of atherosclerosis.     

Platelet function

Platelets are cells which possess broad potential activities in the area of both physiological functions and physiological disorders. The role of platelets in haemostasis with vascular injury is well documented. With vascular and endothelial cell injury, the following sequence of platelet events includes: adhesion, aggregation, secretion. In addition, platelets have a certain role in formation of a permanent haemostatic plug and prolongation of the period of vasoconstriction. There is also the recent evidence of the role of platelets in haemostasis without vessel wall injury. It is evident that platelets play the essential role not only in normal haemostasis but also in wound healing, maintenance of normal plasma homeostasis by endocytosis as well as in inflammation. Platelets play a role in the following pathological events: atherosclerosis, tissue fibrosis, tromboembolism, graft rejection, cancer metastasis. A complete insight into the content of platelet depot organelles, and their functional possibilities requires further research in this area.     

Motor disruption in the production of time intervals with finger taps.

Two experiments with 19 adults examined the variance associated with the motor component in a time production task involving a series of finger taps. Use of the segmentation strategy described by S. Grondin (1992) allowed the isolation of a part of the variance associated with the motor component in such a tapping task. Replacing a finger tap by an internal indicator reduced the coefficient of variation by about .5% per sec. Results show that the choice of subintervals, when an interval is segmented during a timing task, is a major source of variance. The segmentation strategy provides a general framework for analyzing the part of the variability provoked by each of 2 components (the clock and the motor system) involved in a time interval production task. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Platelet glycosaminoglycans in paraproteinemic hemoblastoses

The content and composition of platelet glycosaminoglycans (GAG) were studied in 24 patients with paraproteinemic hemoblastoses (22 patients with myelomic disease and 2 with Waldenstrom's disease). According to the GAG levels, the patients were divided into 2 groups: 1) 6 patients with its higher levels (181 +/- 8 micrograms of uronic acids per 100 mg of acetone-dried cells) and 2) 18 patients with its close-to-normal levels (129 +/- 4 micrograms per 100 mg of the cells). Marked manifestations of hemorrhagic diathesis were found in 5 patients in Group 1 and in 1 in Group 2. Chondroitin sulfate was demonstrated to prevalent in the platelets of patients with paraproteinemic hemoblastoses, as in those of healthy persons. There was GAG electrophoretic profile depletion due to the reduced number of minor components of non- and low-sulfated GAG in 14 patients. It is suggested that the changes detected in the content and composition of GAG may contribute to platelet dysfunction in these diseases.     

Platelet aggregation inhibitors in neurology

This literature review reports on secondary prevention of ischaemic stroke. The aim of secondary prevention is to protect patients who belong to a risk group from the occurrence of brain infarction. Symptomatic patients with a demonstrated carotid artery stenosis of 70% and more will most probably benefit from carotid endarterectomy if performed by a skilled surgeon in the absence of contraindications. Oral anticoagulant drugs play a minor role in the medical prevention of brain infarction. Antiplatelet drugs, however, have been in use for almost two decades and (meta-)analysis of clinical trials points to acetylsalicylic acid as a drug with a modest but certain contribution of about 15% in the endpoint reduction, even at lower dosages. The addition of dipyridamole to classic acetylsalicylic acid dose appears to increase the endpoint reduction to 30%. Neither dipyridamole nor sulfinpyrazone as monotherapy have been demonstrated to be efficacious in the secondary prevention of ischaemic stroke. Ticlopidine seems a promising alternative for acetylsalicylic acid in those patients who suffer adverse effects from acetylsalicylic acid. Ticlopidine itself, however, has a number of side-effects that limit its application. New clinical trials are under way in order to improve the efficacy of drug treatment in the secondary prevention of brain infarction.     

Platelet prostanoid receptors

Prostaglandins (PGs) and thromboxanes are important modulators of platelet activation, and there is strong evidence to support the existence of distinct thromboxane, prostacyclin, PGD2 and PGE2 receptors on the platelet plasma membrane. In this review, each of these platelet prostanoid receptors is discussed in detail, with respect to their receptor pharmacology, molecular biology and signal transduction, and as to any therapeutic implications of the development of specific agonists and/or antagonists. In addition, it considers the possibility that there are separate vascular receptors for 8-epi PGF2 alpha, which are not present on the platelet.     

Platelet GPIIb-IIIa blockers

Regardless of the event that stimulates the aggregation of platelets, the receptor alpha(IIb)beta3--one of a family of adhesion receptors known as integrins--has a key role in the process. The past decade has seen the publication of 10 phase III (randomised) clinical trials of four members of a new class of antiplatelet drugs, the GPIIb-IIIa blockers, targeted at this important receptor. Three (abciximab, eptifibatide, and tirofiban) are licensed for human use. 10 other GbIIb-IIIa blockers are in phase II or III human studies. In all 10 placebo-controlled trials, done in the clinical settings of percutaneous coronary intervention or acute coronary syndrome in patients on aspirin, the endpoints favoured the active drug, with a risk reduction for death or non-fatal myocardial infarction of about 21% overall. With attention to heparin dose the risk of bleeding is not a major concern with these agents. The GPIIb-IIIa blockers are taking the clinician and patient out of the era of aspirin monotherapy when platelet inhibition is required.     

Platelet lipoxygenase in spontaneously hypertensive rats

We have previously reported that the nonselective lipoxygenase inhibitor phenidone is a potent hypotensive agent in the spontaneously hypertensive rat (SHR). In the present study, we examined the relationship between production of platelet 12-hydroxyeicosatetraenoic acid (12-HETE) and intra-arterial blood pressure in SHR and Wistar-Kyoto rats (WKY) using both a cross-sectional analysis and an acute pharmacological intervention. Basal generation rate of 12-HETE by platelets collected from the SHR was approximately 3.7-fold higher than in the WKY (0.86 +/- 0.24 versus 0.23 +/- 0.05 nmol/mL per 10 minutes, respectively; P < .01). Systolic arterial pressure was positively related to platelet 12-HETE formation rate when the entire rat population was considered (r = .70, P < .001). The specific 12-lipoxygenase inhibitor cinnamyl-3,4-dihydroxycyanocinnamate induced lowering of both arterial blood pressure and platelet 12-lipoxygenase activity in SHR. At 15 mg/kg, cinnamyl-3,4-dihydroxycyanocinnamate elicited a marked hypotensive effect in SHR but not in WKY. This reduction in arterial pressure was accompanied by an approximate 70% inhibition in platelet 12-HETE production rate. The return of high blood pressure to basal levels was associated with a significant rise in the production of platelet 12-HETE toward control values (baseline, 0.97 +/- 0.33 nmol/mL per 10 minutes; nadir of blood pressure, 0.19 +/- 0.03; resumption of basal pressure, 0.42 +/- 0.14). In contrast, captopril (15 mg/kg) induced a quantitatively similar decrease in blood pressure but had no effect on platelet 12-HETE generation rate. Thus, hypertension in SHR is linked to increased production rate of platelet 12-HETE. Acute blood pressure reduction attained during lipoxygenase inhibition but not by angiotensin converting enzyme inhibition leads to a concomitant reduction in the production of platelet 12-HETE. We speculate that since rat arterial tissue produces 12-HETE, increased 12-lipoxygenase activity in SHR may contribute to the maintenance of elevated arterial pressure in this strain.     

Platelet antibodies in patients with migraine

The newer antifungal agents are increasingly being used for the treatment of onychomycosis. Tinea unguium is uncommon in children. In young children who are unable or unwilling to swallow capsules, the alternative to itraconazole capsules may be the oral solution. The pharmacokinetics of the itraconazole capsule when it is broken open and the contents sprinkled onto food has not been reported. Two sisters, ages 8 and 11 years, presented with fingernail dystrophy that was confirmed to be onychomycosis due to Trichophyton rubrum and T. soudanense, respectively. The patients were reluctant to swallow capsules and were treated with itraconazole pulse therapy using the oral solution, 3 mg/kg/day. The treatment regimen consisted of two pulses, each 1 week long, with a 3-week period between pulses. Both patients were clinically and mycologically cured with no adverse effects. Itraconazole oral solution (3 mg/kg/day) given as pulse therapy may be a consideration in the treatment of onychomycosis in some children.