Biochemical and Electron Microscopic Study of Preserved Erythrocytes

The age population distribution as judged by the ultrastructure of red cell membranes ("ghosts"), prepared by gradual osmotic hemolysis, was studied during storage in parallel with some of the biochemical changes that characterize the storage lesion. The loss of cholesterol and phospholipids and the decrease in DPG and the delayed decrease of ATP together with the increase in inorganic phosphate indicated a typical storage lesion, however, no significant modification in the proportion of structurally old red cell membranes was found. It is concluded that the storage lesion can not be morphologically identified with physiological aging of erythrocytes from the electron microscopical point of view.     

Platelet monoamine oxidase in women with premenstrual syndrome

Platelet monoamine oxidase (MAO) and RBC catechol-O-methyltransferase (COMT) were studied in 12 women suffering from premenstrual syndrome. No significant variation of platelet MAO or RBC COMT was found during the menstrual cycle, as opposed to previous studies on normal women and monkeys, which report a significant decline of platelet MAO activity in the 5-day period before menses.     

The diagnosis of polyarteritis nodosa. I. A literature-based decision analysis approach

We investigated diagnostic testing in polyarteritis nodosa (PAN) by calculating, from published data, the sensitivity and specificity of visceral angiography and muscle, nerve, testicle, kidney, and liver biopsy. Test sequence strategies were constructed by Bayesian inference using a computer program written for this purpose. Test sequences were compared with an aggressive strategy consisting of repeated tests until there was a positive finding or until the available tests were exhausted, and a conservative strategy consisting of 1 biopsy procedure plus angiography. The Bayesian analysis agreed most closely with the conservative approach for most prior probabilities (degree of suspicion) that a patient had PAN. The aggressive strategy had an overall sensitivity of 90% and specificity of 91%, whereas the conservative strategy was 85% sensitive and 96% specific. Furthermore, the aggressive strategy was more costly ($2,986 versus $1,961) and had a higher rate of morbidity (3.8 versus 2.7 days of hospitalization per patient evaluated) than did the conservative strategy. The mortality rates of both strategies were equivalent (approximately 0.05 deaths per hundred patients evaluated). The per-case cost of diagnosis increased as prevalence decreased, and at 10% prevalence, the aggressive strategy cost more than $17,000 per case diagnosed. Sensitivity analysis revealed that the strategies were moderately affected by the test characteristics, within reasonable assumptions, but that the differences in conservative and aggressive approaches remained. Thus, our analysis based on available data and the assumption of test independence suggests that the preferred diagnostic evaluation of patients with symptoms suggestive of PAN consists, in most cases, of a single biopsy procedure, with angiographic evaluation if necessary.     

Factor XI and Platelets: Evidence that Platelets Contain only Minimal Factor XI Activity and Antigen

Factor-XI activity of platelets has been studied in platelet-rich plasmas and isolated platelet suspensions. Fresh platelets in both environments had little or no measurable factor-XI activity. Frozen and thawed platelet-rich normal plasma had markedly elevated apparent factor-XI activity and factor-IX activity as compared to platelet-poor plasma. Frozen and thawed platelet-rich and platelet-poor normal plasmas had equivalent factor-XI antigen. Platelets isolated from normal blood and from factor-XI deficient blood had the same small amounts of apparent factor-XI activity, which increased slightly on freezing and thawing. The data indicates that minimal factor XI is associated with the platelet. The markedly elevated apparent factor-XI activity of frozen and thawed platelet-rich plasma is shown to reflect the interaction of a platelet activator with plasma clotting factors to produce a later activated-clotting-intermediate.     

Safety of anticoagulation therapy in well-informed older patients

BACKGROUND: In older populations, oral anticoagulation therapy (OAT) is underused by physicians, mainly because of fear of bleeding complications. The aim of this study was to determine the incidence of bleeding complications and associated risk factors in a large heterogeneous group of older patients. METHODS: Combined retrospective and prospective cohort study conducted in geriatric and internal medicine departments. All patients 80 years or older discharged with the recommendation of OAT were followed up for a mean +/- SD of 28.8 +/- 36.3 months. The rate of bleeding events and the quality of anticoagulation were compared across a wide range of demographic and clinical variables and cognitive and functional status. In addition, we assessed the quality of education given to the patient or caregiver on the use of OAT. RESULTS: Among 15 387 patients 80 years or older, 323 (2.1%) were discharged with the recommendation of OAT. The rate of major bleedings was 2.4 events per 1000 patient-months. Socioeconomic and cognitive variables and functional impairments were not associated with an increased rate of bleeding. In multivariate analysis, insufficient education on OAT as perceived by the patient or caregiver (odds ratio [OR], 8.83), polypharmacy (OR, 6.14), and international normalized ratio values above the therapeutic range (OR, 1.08) were the only significant predictive factors for bleeding complications. CONCLUSIONS: The rate of bleeding complications, especially major bleedings, was low in this large group of older patients, many with comorbidities and cognitive and functional impairments. Insufficient OAT education was the major factor that predicted bleeding. Therefore, improving and fostering better methods of OAT education may further reduce bleeding complications.     

Somatic NRAS mutation in patient with generalized lymphatic anomaly

Generalized lymphatic anomaly (GLA or lymphangiomatosis) is a rare disease characterized by a diffuse proliferation of lymphatic vessels in skin and internal organs. It often leads to progressive respiratory failure and death, but its etiology is unknown. Here, we isolated lymphangiomatosis endothelial cells from GLA tissue. These cells were characterized by high proliferation and survival rates, but displayed impaired capacities for migration and tube formation. We employed whole exome sequencing to search for disease-causing genes and identified a somatic mutation in NRAS. We used mouse and zebrafish model systems to initially evaluate the role of this mutation in the development of the lymphatic system, and we studied the effect of drugs blocking the downstream effectors, mTOR and ERK, on this disease.     

Can creatinine clearance be accurately predicted by formulae in octogenarian in-patients?

BACKGROUND: As serum creatinine is relatively inaccurate for estimating renal function, prediction formulae are commonly used for more precise renal function estimation. However, these equations have not been studied in acutely hospitalized octogenarian patients. AIM: To compare three commonly used formulae for estimating GFR to measured creatinine clearance (CCR) in patients aged >/=80 years admitted to an acute geriatric department. DESIGN: Prospective, observational study. METHODS: Consecutive patients aged >/=80 years with urinary catheters, admitted over a 12-month period to the acute geriatric ward of a 600-bed university hospital, were enrolled in the study. All had an accurate 24-h urinary collection, as well as serum and urinary urea and creatinine determinations. CCR was calculated and compared with GFRs derived from the three formulae. RESULTS: Of the 154 patients enrolled in the study, 107 (69.5%) had normal serum creatinine (相似文献