Gamma backscattering analysis of flaw types and orientation based on Monte Carlo GEANT4 simulations.

In this study, we modeled the effects of flaws in a solid material as three different slit types (rectangular, rectilinear, and semicircular) and their orientations in a duralumin (aluminum alloy) plate in simulations based on 137Cs gamma backscattering. The simulations were performed using the Monte Carlo GEANT4 simulation toolkit. The simulation results showed that the shape of the slit had a small effect on the backscattering peak curve. Rotating the slit on the Y-axis and Z-axis of the duralumin plate influenced the 137Cs backscattering peak height in the energy range from 0.185 to 0.20 MeV, where the backscattering peak areas exhibited specific patterns due to the slit orientations.

Salivaricin 9, a new lantibiotic produced by Streptococcus salivarius.

Salivaricin 9 (Sal9) is a 2560 Da lantibiotic having just 46 % amino acid identity with its closest known homologue, the Streptococcus pyogenes lantibiotic SA-FF22. The Sal9 locus (designated siv) in Streptococcus salivarius strain 9 was partially sequenced and localized to an approximately 170 kb megaplasmid, which also harbours the locus for the lantibiotic salivaricin A4. The entire locus was fully characterized in the draft genome sequence of S. salivarius strain JIM8780 and shown to consist of eight genes, having the following putative functions: sivK, sensor kinase; sivR, response regulator; sivA, Sal9 precursor peptide; sivM, lantibiotic modification enzyme; sivT, ABC transporter involved in the export of Sal9 and concomitant cleavage of its leader peptide; and sivFEG, encoding lantibiotic self-immunity. Intriguingly, in contrast to strain 9, the siv locus was chromosomally located in strain JIM8780--the first lantibiotic locus shown not to be exclusively plasmid-associated in S. salivarius. Sal9-containing extracts specifically induced lantibiotic production in both strain 9 and strain JIM8780, indicating that Sal9 functions as a signal peptide for upregulation of its own biosynthesis. Screening representative strains of three streptococcal species (S. salivarius, S. pyogenes and S. mitis) for sivA indicated that it was present only in S. salivarius, with 12 of 28 tested S. salivarius positive. Since Sal9 was inhibitory to all tested S. pyogenes strains it appears to have potential as an important component of the bacteriocin armoury of S. salivarius probiotics intended to control S. pyogenes infections of the human oral cavity.

Characterization of lactosporin, a novel antimicrobial protein produced by Bacillus coagulans ATCC 7050.

AIMS: To characterize the antimicrobial protein produced by Bacillus coagulans used in the probiotic dietary supplement (Lactospore) Probiotic, Sabinsa Corp., Piscataway, NJ, USA). METHODS AND RESULTS: Bacillus coagulans ATCC 7050 was grown at 37 degrees C for 18 h. The cell free supernatant was concentrated 10-fold (lactosporin preparation, LP). The antimicrobial activity of LP was confirmed against Micrococcus luteus ATCC 10420 in a well diffusion assay. The proteinaceous nature of LP was determined following exposure to different enzymes. The activity of LP was pH-dependent but stable to heat. The isoelectric point of LP was determined to be 3.5-4.0. PCR analyses showed no similarity between lactosporin and known antimicrobial proteins produced by the Bacillus spp. CONCLUSIONS: Lactosporin is a novel antimicrobial protein. Initial characterization indicates that it may fall outside of the conventional classification of class I and II bacteriocins. Loss of activity after exposure to a number of proteolytic enzymes and lipase suggest that lactosporin may posses a lipid moiety which contributes to its inhibitory activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The unique characteristics of lactosporin, including its antimicrobial activity against pathogenic micro-organisms, indicate that it may have potential for application in foods and personal care products.

Isolation of the Bacillus subtilis antimicrobial peptide subtilosin from the dairy product-derived Bacillus amyloliquefaciens.

AIMS: To purify and characterize an antimicrobial protein (bacteriocin) isolated from the dairy product-derived Bacillus amyloliquefaciens. METHODS AND RESULTS: An unknown bacterial species cultured from the Yogu Farm probiotic dairy beverage was identified through 16S ribosomal RNA analysis as B. amyloliquefaciens, a phylogenetically close relative of Bacillus subtilis. The cell-free supernatant (CFS) of overnight cultures was active against Listeria monocytogenes and also against clinical isolates of Gardnerella vaginalis and Streptococcus agalactiae. At the same time, several isolates of vaginal probiotic Lactobacilli were resistant to the CFS. The nature of the compound causing inhibitory activity was confirmed as proteinaceous by enzymatic digestion. The protein was isolated using ammonium sulfate precipitation, and further purified via column chromatography. PCR analysis was conducted to determine relatedness to other bacteriocins produced by Bacillus spp. CONCLUSION: The antimicrobial protein isolated from B. amyloliquefaciens was shown to be subtilosin, a bacteriocin previously reported as produced only by B. subtilis. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of intra-species horizontal gene transfer for subtilosin and the first fully characterized bacteriocin isolated from B. amyloliquefaciens. Finally, this is the first report on subtilosin's activity against bacterial vaginosis-associated pathogens.

Iron status and oxidative stress in beta-thalassemia patients in Jakarta.

A study on thalassemia intermedia and major patients in Jakarta was initiated to obtain a comprehensive picture of metabolic dysregulation, iron overload, oxidative stress, and cell damage. Data are presented from a group of 14 transfusion-dependent patients in an age range of 11-25 years (T) and another group of 9 frequently transfused (for at least 15 years) patients aged 17-30 years (L). A third group comprised 6 patients (aged 7 to 14 years) who had not yet obtained transfusions (N). The 21 controls (C) were voluntary students without diagnosis or clinical signs of thalassemia up to 30 years of age. The study was approved by the Ethical Clearance Board of the Medical Faculty and all blood samples from controls and patients were obtained on fully informed consent. Levels of antioxidants (vitamins A, C, E and beta-carotene) and reactive thiols are considerably decreased in transfused patients, whereas signs of iron overload and cell damage are increased (serum iron, ferritin, transferrin saturation, SGOT, SGPT, gamma-GT, bilirubin). Results can be summarized that non-transfused thalassemia intermedia patients exert slight signs of oxidative stress, and increased hemoglobin degradation but no significant indication of tissue or cell damage. This picture differs considerably from transfusion-dependent thalassemia major patients: highly significant decrease in antioxidants and thiols and tremendous iron overload and cell damage. The picture is even worsened in long-term transfused patients. Iron chelation after transfusion is not sufficient in Indonesia, because it is normally (with few exceptions) applied only once together with transfusion. Hence, one major reason of the bad condition of transfusion-dependent thalassemia patients in Indonesia appears to be frequent transfusions (on the average one per month) and insufficient chelation of one treatment per month together with transfusion.

Proposed evaluation of laboratory performance in an external hematology quality control scheme.

The commercial control material for hematology Cell Dyn 16 Tri Level gave a good precision an accuracy using the four blood cell counters currently mostly used in Indonesia, the Coulter, Sysmex, Serono and Cell Dyn. It could be used as one of the hematology control material in an external quality control scheme. Result of the CV from participating laboratories are higher compared to this trial are caused by different level of laboratory technical ability although the geographical area and climate may also play a role. The new scoring calculation to evaluate the participant's performance gave a more wider range of DI scores, to give better insight to the performance of each laboratory.

Country report: the Indonesian NEQAS on hematology. National External Quality Assessment Scheme.

Around six hundred clinical laboratories in all the province of Indonesia participated the Indonesian National External Quality Assessment Scheme (NEQAS) on Hematology (Program Nasional Pemantapan Kualitas Laboratorium Klinik bidang Hematologi). Automated analyzer gave better results compared to the manual method. For hemoglobin, the CV of automated analyzer and manual method were 2.8% and 9.1%, respectively. The CV of automated analyzer and manual method for leukocyte count were 8.3% and 32.3%; for erythrocyte count were 9.7% and 80.8%; and for thrombocyte count were 10.3% and 45.9%. We observe no significant improvement of the overall performance from 1986 to 1998. Quality control material for NEQAS on hematology is still a problem. The artificial particles seem not behave exactly like the human cells (leukocytes, thrombocytes).

The effect of Norplant on some hemostatic parameters in Indonesian women.

Many reports have indicated that oral contraceptives can increase the incidence of thromboembolic disorders. Norplant, an implant contraceptive containing levonorgestrel, has been developed recently. The aim of this study is to observe the effect of Norplant on some hemostatic parameters. The subjects in this study were divided into 5 groups. Group 1 (control) consisted of 25 female blood donors. Group 2 (N = 25), group 3 (n = 25), group 4 (n = 17) and group 5 (N = 20) consisted of subjects who had been using Norplant for 2, 3, 4, and 5 years, respectively. Prothrombin time, activated partial thromboplastin time, fibrinogen level, assay of F VII and X, antithrombin III activity, plasminogen activity, alpha 2-plasmin inhibitor activity and platelet aggregation test were done in all subjects. Our results showed that there was a significant difference (p < 0.05) on platelet aggregation induced by 10 microM of ADP between the control group and Norplant users for more than 2 years, while the other parameters did not differ significantly. It is concluded that 5 years users of Norplant did not alter blood coagulability, but increased platelet response to 10 microM of ADP.

Features of DIC in dengue hemorrhagic fever.

Collaborative studies on hemostasis in dengue hemorrhagic fever (DHF) patients by Indonesian and Japanese teams revealed that all DHF patients had manifestations of the acute type of disseminated intravascular coagulation (DIC). Prolongations of activated partial thromboplastin time and prothrombin time and decreases of platelet counts, fibrinogen, prothrombin, factor VIII, plasminogen and antithrombin III activities were observed transiently during the acute stage of DHF. It was also found that alpha 2 antiplasmin was decreased in the acute stage to 32% of the normal level on the average. This may characterize the hemorrhagic diathesis of the DHF patients.

Investigation of coagulation abnormalities in patients with erythema nodosum leprosum.

Twenty erythema nodosum leprosum (ENL) patients were examined. Coagulation studies were carried out in 13 of them during their active stage and 7 in the latent stage. From these 13 patients, 6 were re-examined when the disease became latent. From these observations a conclusion can be drawn that there are coagulation abnormalities in the majority of ENL patients in the active stage and these abnormalities will return to normal values when the disease becomes latent.