Direct effects of luteal regression on anterior pituitary response to GNRH

BACKGROUND: The risk of acquiring Lyme disease is high in areas in which the disease is endemic, and the development of a safe and effective vaccine is therefore important. METHODS: We conducted a multicenter, double-blind, randomized trial involving 10,936 subjects who lived in areas of the United States in which Lyme disease is endemic. Participants received an injection of either recombinant Borrelia burgdorferi outer-surface lipoprotein A (OspA) with adjuvant or placebo at enrollment and 1 and 12 months later. In cases of suspected Lyme disease, culture of skin lesions, polymerase-chain-reaction testing, or serologic testing was done. Serologic testing was performed 12 and 20 months after study entry to detect asymptomatic infections. RESULTS: In the first year, after two injections, 22 subjects in the vaccine group and 43 in the placebo group contracted definite Lyme disease (P=0.009); vaccine efficacy was 49 percent (95 percent confidence interval, 15 to 69 percent). In the second year, after the third injection, 16 vaccine recipients and 66 placebo recipients contracted definite Lyme disease (P<0.001); vaccine efficacy was 76 percent (95 percent confidence interval, 58 to 86 percent). The efficacy of the vaccine in preventing asymptomatic infection was 83 percent in the first year and 100 percent in the second year. Injection of the vaccine was associated with mild-to-moderate local or systemic reactions lasting a median of three days. CONCLUSIONS: Three injections of vaccine prevented most definite cases of Lyme disease or asymptomatic B. burgdorferi infection.     

Autoimmune hepatitis. Clinical characteristics and response to treatment in a series of 49 spanish patients

The clinical and evolutive characteristics and the response to treatment of a series of 49 patients with autoimmune hepatitis (AIH) diagnosed in the Liver Unit of a tertiary hospital from 1979 to 1996 and followed over 5.6 +/- 0.7 years were reviewed. Forty cases (80.4%) were AIH type 1 (ANA/AML positive), 7 (14%) type 2 (ALKM positive) and 2 (5%) of an undetermined type (absence of detectable antibodies). In 13 (26.6%) the disease presented as acute hepatitis and 16 (32%) presented extrahepatic manifestations. The AIH type 2 was observed in younger patients with the debut being more acute than in AIH type 1, but no significant differences were observed between the two groups with regard to the results of laboratory tests, frequency of a systemic manifestations and histologic lesions. Immunosuppressive treatment was effective in 90% of the cases, but 11 (30%) out of 37 relapsed on suppression of prednisone or reduction of the dosis. All showed response on reinitiation or an increase in the dosis of prednisone. Progression to cirrhosis was observed in 17% of the patients without cirrhosis at the time of diagnosis despite biochemical remission induced by treatment. No patient died during the follow up but 4 required liver transplantation.     

Effects of silymarin in alcoholic patients with cirrhosis of the liver: results of a controlled, double-blind, randomized and multicenter trial

BACKGROUND/AIMS: Silymarin has protective effects in different experimental conditions, but its efficacy in human liver cirrhosis has not been completely established. Therefore, this study was carried out to determine the effect of silymarin in alcoholics with liver cirrhosis with respect to survival and clinical and laboratory changes. METHODS: From February 1986 to June 1989, we enrolled 200 alcoholics with histologically or laparoscopically proven liver cirrhosis in a randomized, double-blind multicenter trial comparing 450 mg of silymarin (150 mg/ three times per day) with placebo. The primary outcome was time to death, and the secondary outcome was the progression of liver failure. Additional analyses were also performed in 75 patients in whom anti-hepatitis C virus antibodies were measured after completion of the trial. RESULTS: One hundred and three patients were assigned to receive silymarin and 97 to receive placebo. The two groups were well matched for demographic and baseline clinical and laboratory features. A 2-year study period was completed in 125 patients (57 receiving silymarin and 68 receiving placebo). Twenty-nine patients (15 receiving silymarin, and 14 receiving placebo) died during the trial. Survival was similar in patients receiving silymarin or placebo. The effect of silymarin on survival was not influenced by sex, the persistence of alcohol intake, the severity of liver dysfunction or by the presence of alcoholic hepatitis in the liver biopsy. Silymarin did not have any significant effect on the course of the disease. No relevant side-effects were observed in any group. CONCLUSIONS: The results of this study indicate that silymarin has no effect on survival and the clinical course in alcoholics with liver cirrhosis.     

Single-frequency operation of diode-laser-array transverse-pumped Q-switched Nd:YAG laser

Single-longitudinal-mode and single-transverse-mode operation of a miniature Nd:YAG laser transversely pumped by a quasi-CW diode-laser array is described. By injection-seeding this oscillator with a diode-laser end-pumped Nd:YAG microlaser, single-frequency Q-switched pulses of 0.25 mJ energy and 35 ns duration were generated.<>     

Management of ascites in the patient with portal hypertension with emphasis on spontaneous bacterial peritonitis

The reintroduction of paracentesis has modified the way in which patients with ascites are treated. Transjugular intrahepatic portosystemic shunt can be an alternative treatment for patients with refractory ascites and for those patients with hepatorenal syndrome, although more studies are needed to clarify its usefulness and safety. The use of more potent and less nephrotoxic antibiotics together with an earlier diagnosis have improved the outcome of patients with spontaneous bacterial peritonitis (SBP). Oral antibiotics can be used in patients with SBP and good clinical conditions with an efficacy similar to that obtained with intravenous antibiotics. Prophylactic antibiotics in SBP should be restricted to cirrhotic patients at high risk, including bleeding cirrhotic patients, those with a past history of SBP, and those with low protein content in ascitic fluid. This chapter describes the management of ascites in patients with portal hypertension.     

Efficient architectures for sparsely-connected high capacity associative memory models

In physical implementations of associative memory, wiring costs play a significant role in shaping patterns of connectivity. In this study of sparsely-connected associative memory, a range of architectures is explored in search of optimal connection strategies that maximize pattern-completion performance, while at the same time minimizing wiring costs. It is found that architectures in which the probability of connection between any two nodes is based on relatively tight Gaussian and exponential distributions perform well and that for optimum performance, the width of the Gaussian distribution should be made proportional to the number of connections per node. It is also established from a study of other connection strategies that distal connections are not necessary for good pattern-completion performance. Convergence times and network scalability are also addressed in this study.     

Electromechanical Properties of Porous Piezoelectric Ceramics

A theoretical approach is forwarded to predict the electromechanical properties of porous piezoelectric ceramics. The analysis is able to account for the effects of porosity shape and concentration and is applicable to piezoelectric ceramics of arbitrary material symmetry. By coupling the exact solution for a single ellipsoidal pore embedded in an infinite piezoelectric matrix with an effective medium approximation, the theory considers, in an approximate manner, interaction effects at finite porosity concentrations. The theoretical estimates are developed using a matrix formulation which enables all elastic, dielectric, and piezoelectric moduli of the porous solid to be readily computed. Numerical results are presented to illustrate the effects of the shape and concentration of the porosity on the effective electroelastic moduli and transducer parameters of practical importance. Particular attention is devoted to assessing the sensitivity of the effective electromechanical properties to the accuracy of the input data. Finally, theoretical estimates are shown to be in good agreement with existing experimental results for porous piezoelectric ceramics with various microstructural geometries.     

CONTACT BETWEEN A SMOOTH MICROSPHERE AND AN ANISOTROPIC ROUGH SURFACE

This article discusses the effects of asperities on elastic and adhesive contact between a smooth sphere and a rough surface. Two numerical methods are introduced: an asperity-superposition method and a direct-simulation method. In the first method, geometric parameters such as asperity heights, orientations, and radii of curvature are identified by a least-squares regression of neighboring surface heights measured using an atomic force microscope. The rough surface is reconstructed by the superposition of these asperities. The modeling of adhesive and elastic contacts begins with the modeling of a single parabolic-shaped asperity contact. A generalized JKR model for an arbitrary parabola is developed to suit this purpose. The contact between the rough surface (represented by the supposition of parabolic-shaped asperities) and the sphere consequently is modeled bythe mapping and integration of individual asperity contacts. In the second method, pure-elastic contact is modeled by half-space elastic theory. A contact-search algorithm is used to find solutions on the displacement and the contact-pressure distribution that satisfy both the load-displacement equation and the contactboundary conditions. Results from both methods are compared to reveal the effects of asperities on adhesion and elastic-contact pressure.