Purification and properties of a fibrinolytic enzyme from Bacillus subtilis

A fibrinolytic enzyme obtained from B. subtilis was purified, using DEAE-cellulose column chromatography, and gel filtration on Sephadex G-100. The preparation was homogeneous as tested by gel filtration on Sephadex G-200, and disc electrophoresis. The molecular weight of this enzyme was 29.400 estimated by gel filtration on Sephadex G-100. The optimum pH for enzyme activity was 7.2. Copper ions significantly increased enzyme activity, while Zn⁺⁺ and Mn⁺⁺ caused marked inhibition.     

Time course of hypo-osmotic swellings of human spermatozoa: evidence of ordered transition between swelling subtypes

The hypo-osmotic swelling test (HOST or HOS test) usually takes into consideration the total HOS response value with no emphasis either on the value of the response subtypes or the response evaluation time. This study investigated the time course of HOS responses and analysed their physiological relevance. Raw semen spermatozoa and Percoll washed spermatozoa were used in the experiment. The morphological changes in the sperm tail were monitored by incubating the spermatozoa in the hypo- osmotic solution for 16 different time periods. The HOS reactive spermatozoa and the type of HOS reaction (swelling subtypes) of the samples subjected to different duration of treatment were identified under a phase contrast microscope. Also the fate of individual spermatozoa in a hypo-osmotic environment were monitored for 30 min. In spermatozoa exposed to a hypo-osmotic solution, the motility lasted usually less than 2 min and motility characteristics were uniquely different from that of the spermatozoa under iso-osmotic conditions. The HOS response development was permanent but the motility loss due to hypo-osmotic shock was reversible up to 1 min of incubation. There was an indication of ordered transition among the HOS swelling subtypes apparently initiating with subtype b destined to c, d, e, f and g. Further, the subtypes a and g showed gradual decrease and increase, respectively, while subtype b showed abrupt initial increase and then gradual decrease. Transition from b to g could be direct or via one or more than one subtypes. Ultrastructure based analysis indicated that HOS response subtypes are the apparent reflection of the differences in the cytoskeletal assembly of the sperm tail and thus may be identifying different physiological variants in the sperm population. These results indicate that shorter incubation is essential to document the kinetics of various HOS responses but the conventional HOS test misses these important HOS features because of lengthy incubation. Since the time course of ordered transition of HOS responses will vary more than the total HOS response in semen of different aetiologies, the importance of HOS response subtypes and response evaluation time should be taken into consideration when applying HOS test.      

Changes in lipid profile variables in response to submaximal and maximal exercise in trained cyclists

This study examined the effect of prolonged submaximal exercise followed by a self-paced maximal performance test on cholesterol (T-Chol), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC). Nine trained male athletes cycled at 70% of maximal oxygen consumption for 60 min, followed by a selfpaced maximal ride for 10 min. Venous blood samples were obtained at rest, at 30 and 60 min during submaximal exercise, and immediately after the performance test. Lactic acid, haematocrit (Hct), haemoglobin (Hb), T-Chol and TG were measured in the blood, while plasma was assayed for HDL-C. Plasma volume changes in response to exercise were calculated from Hct and Hb values and all lipid measurements were corrected accordingly. In order to ascertain the repeatability of lipid responses to exercise, all subjects were re-tested under identical testing conditions and experimental protocols. When data obtained during the two exercise trials were analysed by two-way ANOVA no significant differences (P > 0.05) between tests were observed. Consequently the data obtained during the two testing trials were pooled and analysed by one-way ANOVA. Blood lactic acid increased non-significantly (P > 0.05) during the prolonged submaximal test, but rose markedly (P < 0.05) following the performance ride. Lipid variables ascertained at rest were within the normal range for healthy subjects. ANOVA showed that blood T-Chol and TG were unchanged (P > 0.05), whereas HDL-C rose significantly (P < 0.05) in response to exercise. Post hoc analyses indicated that the latter change was due to a significant rise in HDL-C after the performance ride. It is concluded that apparent favourable changes in lipid profile variables occur in response to prolonged submaximal exercise followed by maximal effort, and these changes showed a good level of agreement over the two testing occasions.     

Evidence for the involvement of more than one metal cation in the Schiff base deprotonation process during the photocycle of bacteriorhodopsin

The removal of metal cations inhibits the deprotonation process of the protonated Schiff base during the photocycle of bacteriorhodopsin. To understand the nature of the involvement of these cations, a spectroscopic and kinetic study was carried out on bacteriorhodopsin samples in which the native Ca²⁺ and Mg²⁺ were replaced by Eu³⁺, a luminescent cation. The decay of Eu³⁺ emission in bacteriorhodopsin can be fitted to a minimum of three decay components, which are assigned to Eu³⁺ emission from three different sites. This is supported by the response of the decay components to the presence of ²H₂O and to the changes in the Eu³⁺/bR molar ratio. The number of water molecules coordinated to Eu³⁺ in each site is determined from the change in its emission lifetime when ²H₂O replaces H₂O. Most of the emission originates from two “wet” sites of low crystal-field symmetry—e.g., surface sites. Protonated Schiff base deprotonation has no discernable effect on the emission decay of protein-bound Eu³⁺, suggesting an indirect involvement of metal cations in the deprotonation process. Adding Eu³⁺ to deionized bacteriorhodopsin increases the emission intensity of each Eu³⁺ site linearly, but the extent of the deprotonation (and color) changes sigmoidally. This suggests that if only the emitting Eu³⁺ ions cause the deprotonation and bacteriorhodopsin color change, ions in more than one site must be involved—e.g., by inducing protein conformation changes. The latter could allow deprotonation by the interaction between the protonated Schiff base and a positive field of cations either on the surface or within the protein.     

Exercise induces a change in plasma fibrinogen concentration: fact or fiction?

This study examined the effect of exercise on plasma fibrinogen concentrations with simultaneous measurements of plasma volume changes. Eight moderately active males aged 26.6±3.6 years (mean±SD) completed maximal (VO₂max) and submaximal (75% VO₂max for 30 minutes) exercise trials separated by 7 days. Venous blood samples were obtained at rest, immediately postexercise, and following 30 minutes of recovery. Whole blood was analysed for haematocrit and haemoglobin, while citrated plasma was assayed for fibrinogen levels. Values of haematocrit and haemoglobin before and after exercise were utilised for the estimation of plasma volume changes. Plasma volume decreased (p<0.05) immediately following both maximal (−17.7±5.1%) and submaximal (−14.3±4.1%) exercise. Exercise resulted in decreased plasma fibrinogen levels (maximal exercise: from 266.3±14.5 to 222.2±23.9 mg·dL⁻¹; submaximal exercise: from 239.5±45.4 to 209.7±42.4 mg·dL⁻¹) only when postexercise raw data were corrected for the contraction of plasma volume. It is concluded therefore that changes in plasma volume in response to exercise should be taken into account when interpreting exercise effects on plasma fibrinogen concentration.     

CT-based delineation of lymph node levels and related CTVs in the node-negative neck: DAHANCA, EORTC, GORTEC, NCIC,RTOG consensus guidelines.

BACKGROUND AND PURPOSE: The appropriate application of 3-D CRT and IMRT for HNSCC requires a standardization of the procedures for the delineation of the target volumes. Over the past few years, two proposals--the so-called Brussels guidelines from Grégoire et al., and the so-called Rotterdam guidelines from Nowak et al.--emerged from the literature for the delineation of the neck node levels. Detailed examination of these proposals however revealed some important discrepancies. MATERIALS AND METHODS: Within this framework, the Brussels and Rotterdam groups decided to review their guidelines and derive a common set of recommendations for delineation of neck node levels. This proposal was then discussed with representatives of major cooperative groups in Europe (DAHANCA, EORTC, GORTEC) and in North America (NCIC, RTOG), which, after some additional refinements, have endorsed them. The objective of the present article is to present the consensus guidelines for the delineation of the node levels in the node-negative neck. RESULTS AND CONCLUSIONS: First a short discussion of the discrepancies between the previous Brussels and the Rotterdam guidelines is presented. The general philosophy of the consensus guidelines and the methodology used to resolve the various discrepancies are then described. The consensus proposal is then presented and representative CTVs that are consistent with these guidelines are illustrated on CT sections. Last, the limitations of the consensus guidelines are discussed and some concerns about the direct applications of these guidelines to the node-positive neck and the post-operative neck are described.     

Efficacy of a compliant semicircular Ilizarov pin fixator module for treating infected nonunion of the femoral diaphysis

Percutaneous transosseous Ilizarov wiring, whilst preferred in the tibia because of its unique properties, carries a high risk of complications in the femur. The aim of this work was to evaluate the efficacy of a more patient-friendly semicircular pin external fixator module built up from parts of the Ilizarov fixator components and its use in managing diaphyseal femoral nonunions. A group of 20 patients with infected diaphyseal nonunions of the femur after internal osteosynthesis were included in this study. The mean age of the patients at the time of surgery was 46 years (range 16–60, SD 15.6). The mean morbidity time since the original trauma was 10.2 months (range 6–15, SD 2.5). All the cases were fixed by the described external fixator module. Bony union with resolution of infection occurred in 18 (94.7 %) out of 19 cases after a mean period in the fixator of 11.2 months (range 8–18 SD 2.9). After a mean follow-up period of 3.5 years (range 2–9, SD 2.6), there were 14 excellent, 3 good, 1 fair and 1 poor results from radiological evaluation and 10 excellent, 7 good, 1 fair and 1 poor results from functional assessment. In conclusion, the described semi-circular pin fixator module is patient-friendly and effective in managing infected nonunions of the femoral diaphysis.     

CRIPTO overexpression promotes mesenchymal differentiation in prostate carcinoma cells through parallel regulation of AKT and FGFR activities

Members of the EGF-CFC (Cripto, FRL-1, Cryptic) protein family are increasingly recognized as key mediators of cell movement and cell differentiation during vertebrate embryogenesis. The founding member of this protein family, CRIPTO, is overexpressed in various human carcinomas. Yet, the biological role of CRIPTO in this setting remains unclear. Here, we find CRIPTO expression as especially high in a subgroup of primary prostate carcinomas with poorer outcome, wherein resides cancer cell clones with mesenchymal traits. Experimental studies in PCa models showed that one notable function of CRIPTO expression in prostate carcinoma cells may be to augment PI3K/AKT and FGFR1 signaling, which promotes epithelial-mesenchymal transition and sustains a mesenchymal state. In the observed signaling events, FGFR1 appears to function parallel to AKT, and the two pathways act cooperatively to enhance migratory, invasive and transformation properties specifically in the CRIPTO overexpressing cells. Collectively, these findings suggest a novel molecular network, involving CRIPTO, AKT, and FGFR signaling, in favor of the emergence of mesenchymal-like cancer cells during the development of aggressive prostate tumors.     

Safety and effi cacy of hepatitis A vaccine in children with chronic liver disease

INTRODUCTION Hepatitis A virus (HAV) infection is common. In general, hepatitis A is a self-limited illness with a recovery time measured in months[1]. Young children are often asymptomatic, whereas adults are more likely to be symptomatic and may present…