Two-dimensional analysis of the structure of human von Willebrand factor

Human von Willebrand factor (vWF) is synthesized as an extra large polymer; then, it is converted to lower molecular weight plasma multimers, originally composed of intact 225-kDa subunits, by a metalloproteinase. Proteolysis generates two fragments of 140-and 176-kDa, which originate from cleavage of peptide bond Tyr842-Met843 and which represent vWF residues 1-842 and 843-2050, respectively; a very small amount of 189-kDa fragment can also be found in normal plasma. We describe here a two-dimensional (2-D) method to analyze plasma vWF structure.     

Are frequent short gastro-oesophageal reflux episodes the cause of symptoms in patients with non-ulcer dyspepsia responding to treatment with ranitidine?

BACKGROUND: Patients with non-ulcer dyspepsia (NUD) responding to treatment with H2-receptor antagonists have no clinically useful characteristics. This trial compares the gastro-oesophageal reflux pattern as measured by 24-h oesophageal pH monitoring in patients responding to ranitidine with that of non-responders. METHODS: Thirty-one patients with NUD were randomized to 6 weeks' double-blind alternating treatment with 150 mg ranitidine twice daily or placebo and classified as responders or non-responders. RESULTS: Pathologic gastro-oesophageal reflux was seen in 3 of the 13 responders and 4 of the 18 no-responders (NS). The responders had frequent short reflux episodes (< 1 min in duration). When 4 patients with > or = 5 reflux episodes longer than 5 min were excluded, the number of short reflux episodes (median) in responders and non-responders was 32 and 14, respectively. The difference is statistically significant (p = 0.025). There were no other differences between the groups. CONCLUSIONS: In this study patients with NUD responding to ranitidine were characterized by frequent short reflux episodes in the absence of numerous long reflux episodes.     

Acute tumor lysis syndrome after transcatheter chemoembolization of hepatocellular carcinoma

PURPOSE: Thromboprophylaxis with heparins after total joint replacement is well accepted. The aim of this prospective randomized study was to evaluate the thrombo-prophylactical efficiency of an ankle joint moving device (Artroflow) after total knee arthroplasty. METHOD: In this prospective study 160 patients were examined who had undergone total knee arthroplasty (TKA). All of the 160 patients received Enoxaparin 1 x 40 mg subcutaneously per day. In addition to this, 90 patients received Artroflow three times a day for 30 minutes. The passive movements of the ankle joint lead to an emptying of the foot and calf veins. Except for the daily routine, we performed physical examination and ultrasound in colour, compression and duplex technique one day before surgery and at the 7th and 14th day after surgery. If a thrombosis was suspected, an ascending phlebography was carried through. RESULTS: The overall thrombosis rate was 6.3% (n = 10). 11.4% (n = 70) deep vein thromboses (DVT) could be observed in the group without Artroflow. Thrombosis occurred in the group with Artroflow in 2 cases (2.2%, n = 90). A statistical difference was found between the two patient groups (p < 0.05, Chi-Square-test). One patient was excluded from the study because of pain in the ankle joint at the fourth day of treatment. CONCLUSION: In addition to heparins, this ankle joint moving device can be recommended as a physical way to prevent DVTs in the thromboprophylaxis of total knee arthroplasty.     

Heart rate and workload variations in actual and simulated flight

The monitoring of heart rate in aviation research provides a global index of pilot workload. Heart rate variability is a promising measure but more complex to assess and therefore less often used, especially in dynamic task environments. The application of spectral analysis techniques of heart rate for workload assessment in aviation is illustrated and discussed. Ideally, workload assessment includes real-time or continuous measures to reveal variations in workload as pilots accomplish their tasks. Four studies are discussed that used heart rate measures for the assessment of: (1) training effectiveness; (2) stress of flight instruction; (3) simulator realism; and (4) flight task difficulty. Results indicate that cardiovascular measures are well suited to index different mental states of pilots as well as their dynamic responses to variations in workload.     

Analysis of immunoglobulin genes in splenic marginal zone lymphoma suggests ongoing mutation

BACKGROUND: The incidence of venous thromboembolism has not been well described, and there are no studies of long-term trends in the incidence of venous thromboembolism. OBJECTIVES: To estimate the incidence of deep vein thrombosis and pulmonary embolism and to describe trends in incidence. METHODS: We performed a retrospective review of the complete medical records from a population-based inception cohort of 2218 patients who resided within Olmsted County, Minnesota, and had an incident deep vein thrombosis or pulmonary embolism during the 25-year period from 1966 through 1990. RESULTS: The overall average age- and sex-adjusted annual incidence of venous thromboembolism was 117 per 100000 (deep vein thrombosis, 48 per 100000; pulmonary embolism, 69 per 100000), with higher age-adjusted rates among males than females (130 vs 110 per 100000, respectively). The incidence of venous thromboembolism rose markedly with increasing age for both sexes, with pulmonary embolism accounting for most of the increase. The incidence of pulmonary embolism was approximately 45% lower during the last 15 years of the study for both sexes and all age strata, while the incidence of deep vein thrombosis remained constant for males across all age strata, decreased for females younger than 55 years, and increased for women older than 60 years. CONCLUSIONS: Venous thromboembolism is a major national health problem, especially among the elderly. While the incidence of pulmonary embolism has decreased over time, the incidence of deep vein thrombosis remains unchanged for men and is increasing for older women. These findings emphasize the need for more accurate identification of patients at risk for venous thromboembolism, as well as a safe and effective prophylaxis.     

The expression of voltage-dependent calcium channel beta subunits in human cerebellum

The beta subunits of voltage-dependent calcium channels, exert marked regulatory effects on the biophysical and pharmacological properties of this diverse group of ion channels. However, little is known about the comparative neuronal expression of the four classes of beta genes in the CNS. In the current investigation we have closely mapped the distribution of beta1, beta2, beta3 and beta4 subunits in the human cerebellum by both in situ messenger RNA hybridization and protein immunohistochemistry. To our knowledge, these studies represent the first experiments in any species in which the detailed localization of each beta protein has been comparatively mapped in a neuroanatomically-based investigation. The data indicate that all four classes of beta subunits are found in the cerebellum and suggest that in certain neuronal populations they may each be expressed within the same cell. Novel immunohistochemical results further exemplify that the beta voltage-dependent calcium channel subunits are regionally distributed in a highly specific manner and studies of Purkinje cells indicate that this may occur at the subcellular level. Preliminary indication of the subunit composition of certain native voltage-dependent calcium channels is suggested by the observation that the distribution of the beta3 subunit in the cerebellar cortex is identical to that of alpha(1E). Our cumulative data are consistent with the emerging view that different native alpha1/beta subunit associations occur in the CNS.