No differences in support of thrombin generation by neonatal or adult platelets.

UNLABELLED: Newborns have, despite low clotting factors and poor in vitro platelet function, a well functioning hemostasis. The reason for this is still not completely clear. The aim of our study was to investigate whether phospholipids in neonatal platelets differ from those in adult platelets in their total amount, in their exposure on the platelet surface, and their effect on thrombin generation (TG). METHODS: Clotting times of newborn and adult platelet-rich plasma were measured. Effect of newborn and adult platelets on TG was measured by means of CAT (calibrated automated thrombography). In addition, the effect of newborn and adult platelets with or without stimulation by ionophor on TG was measured in a purified prothrombinase complex. Phosphatidylserine-exposure (PS) of newborn and adult platelets was measured by flow cytometry of annexin V binding. The amount of phospholipids (PL) was determined by means of mass spectrometry. RESULTS: Clotting times of platelet-rich plasma (PRP) of newborns stimulated with ionophor showed a significant lower reduction of clotting time than in adult PRP. No differences in the support of TG between neonatal and adult platelets were found in neonatal or adult plasma by means of CAT. In the purified system TG was increased by adding ionophor stimulated platelets but no difference was evident between stimulated newborn and adult platelets. Flow cytometric analysis showed no difference in annexin V binding between adult and newborn platelets. The results of mass spectrometry showed a very similar amount and pattern of PL of adult and newborns platelets. CONCLUSION: Our results do not provide any evidence that a different PL content or expression of neonatal platelets may alter TG in neonates.

Enhanced thrombin generation in plasma of severe thrombocytopenic patients due to rFVIIa.

UNLABELLED: RFVIIa-enhanced thrombin generation has been shown to be dependent on platelets. In previous work we have shown that addition of monocytes and rFVIIa to microparticle free plasma causes a distinct thrombin generation. The aim of our study has been to examine whether there is enough surface provided by microparticles in thrombocytopenic plasma to allow an effect of rFVIIa. PATIENTS, METHODS: Thrombin generation was measured in platelet rich plasma (PRP) and microparticle free plasma (MFP) of thrombocytopenic haemato-oncological patients with and without addition of rVIIa by means of calibrated automated thrombography. Microparticles were analyzed in PRP by FACS flow cytometry. RESULTS: Microparticle free plasma showed no thrombin generation with or without addition of rFVIIa. Addition of rFVIIa to PRP of thrombocytopenic patients led to a significant shortening of lag time and time to peak in thrombin generation, while ETP and peak remained unchanged. CONCLUSION: Our results show that even in plasma of severe thrombocytopenic patients enough surface may be provided by microparticles to allow an enhancement of thrombin generation by rFVIIa.

Elevated thrombin-forming capacity of tissue factor-activated cord compared with adult plasma.

Clinically observed excellent hemostasis in neonates despite low levels of clotting factors is not completely understood so far. Therefore, we investigated whether physiological low levels of the inhibitor protein C (PC) facilitate thrombin formation in tissue factor (TF)-activated plasma samples. PC was activated by endogenously generated thrombin after addition of soluble thrombomodulin (TM). The capability of activated PC (APC) to suppress thrombin formation was significantly more pronounced in adult than in cord plasma. Addition of 4 nm of TM decreased the thrombin potential (TP) in cord plasma by 10%, and in adult plasma by 52% in the presence of 5 pm TF. We demonstrate that this low anticoagulant action of PC is attributable to the low levels of tissue factor pathway inhibitor (TFPI) and antithrombin (AT) physiologically present in cord plasma. Addition of 4 nm TM decreased the TP by 58% in cord plasma adjusted to contain TFPI and AT at adult levels in the presence of 5 pm TF. Thus, the combined low anticoagulant action of the three inhibitors APC, TFPI, and AT in cord plasma allows enhanced thrombin formation associated with shorter clotting times compared with adult plasma when low amounts of TF are applied to initiate clot formation. Although our laboratory experiments do not allow definite conclusions for various clinical situations, our data might contribute to explain excellent hemostasis in neonates despite low levels of procoagulants.

Blasting injuries in surface mining with emphasis on flyrock and blast area security.

PROBLEM: Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgment or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preventive measures. METHOD: This study examines publications by MSHA, USGS, and other authors. The primary source of information was MSHA's injury-related publications. RESULTS: During the 21-year period from 1978 to 1998, the mean yearly explosive-related injuries (fatal and nonfatal) for surface coal mines was 8.86 (95% CI: 6.38-11.33), and for surface metal/nonmetal mines 10.76 (95% CI: 8.39-13.14). Flyrock and lack of blast area security accounted for 68.2% of these injuries. This paper reviews several case studies of fatal injuries. Case studies indicate that the causative factors for fatal injuries are primarily personal and task-related and to some extent environmental. A reduction in the annual injuries in surface coal mines was observed during the 10-year period of 1989-1998 [5.80 (95% CI: 2.71-8.89) compared to the previous 10-year period of 1979-1988 [10.90 (95% CI: 7.77-14.14)]. However, such reduction was not noticed in the metal/nonmetal sector (i.e., 9.30 [95% CI: 6.84-11.76] for the period 1989-1998 compared with 11.00 [95% CI: 7.11-14.89] for the period 1979-1988). DISCUSSION: A multifaceted injury prevention approach consisting of behavioral/educational, administrative/regulatory, and engineering interventions merits consideration. IMPACT ON INDUSTRY: The mining community, especially the blasters, will find useful information on causative factors and preventive measures to mitigate injuries due to flyrock and lack of blast area security in surface blasting. Discussion of case studies during safety meetings will help to mitigate fatal injuries and derive important payoffs in terms of lower risks and costs of injuries.

[Effect of fibroscopic sclerotherapy of hemorrhaging esophageal varices on survival in alcoholic liver cirrhosis (comparative retrospective study)]. / Nyelöcsö visszérrepedésböl eredö vérzés fiberoszkópos szklerotizáló kezelésének hatása a túlélésre alkoholos eredetú mäjcirrhosisban (Osszehasonlító, retrospektív tanulmány).

UNLABELLED: Between 1983 and 1992 altogether 638 alcoholic cirrhotic patients had been treated because of acute esophageal variceal bleeding. In 96 cases the treatment were carried out in the following circumstances; volume and coagulation factor substituate, vasopressin or glypressin and nitroglycerin, urgent endoscopy and ballontamponade but in 47 cases an urgent sclerotherapy were also performed. The survival, cases of rebleeding,-from the first bleeding events-of the 49 nonsclerosed patients were compared to those of the 47 sclerosed one. CONCLUSIONS: 1. The endoscopic sclerotherapy proved to be life-saving procedure. 2. Within 30 days the nonsclerosed patients died twice as much number than the slcerosed patients. 3. The lengths of the survival period were found four and half times so long at the sclerosed patients than in nonsclerosed patients (535 versus 125 days). 4. The numbers of the rebleeding were not less at the sclerosed patients than the nonsclerosed subjects. 5. The lengths of the nonbleeding period was found triple so long at the sclerosed patients than in nonsclerosed patients. 6. The survival of the "Child C" patients at the sclerosed and nonsclerosed patients, too. The authors come to conclusion that by the fiberendoscopic sclerotherapy an increase in the survival time of the patients with acute esophageal variceal bleeding in alcoholic cirrhosis can be achieved.