Prognostic Factors and Scoring System for Death from Visceral Leishmaniasis: An Historical Cohort Study in Brazil

Background

In Brazil, case-fatality rates attributable to visceral leishmaniasis (VL) are high and knowledge of the risk factors associated with death may help reduce mortality. The aim of this study was to construct and validate a scoring system for prognosis of death from VL by using all cases reported in Brazil from 2007 to 2011.

Methodology

In this historical cohort study, 18,501 VL cases were analyzed; of these, 17,345 cases were cured and 1,156 cases caused death. The database was divided into two series: primary (two-thirds of cases), to develop the model score, and secondary (one-third of cases), to validate the scoring system. Multivariate logistic regression models were performed to identify factors associated with death from VL, and these were included in the scoring system.

Principal Findings

The factors associated with death from VL were: bleeding (score 3); splenomegaly (score 1); edema (score 1); weakness (score 1); jaundice (score 1); Leishmania–HIV co-infection (score 1); bacterial infection (score 1); and age (≤0.5 years [score 5]; >0.5 and ≤1 [score 2]; >19 and ≤50 [score 2]; >50 and <65 [score 3]; ≥65 [score 5]). It was observed that patients with a score of 4 had a probability of death of approximately 4.5% and had a worse prognosis. The sensitivity, specificity, and accuracy of this score were 89.4, 51.2, and 53.5, respectively.

Conclusions/Significance

The scoring system based on risk factors for death showed good performance in identifying patients with signs of severity at the time of clinical suspicion of VL and can contribute to improving the surveillance system for reducing case fatalities. The classification of patients according to their prognosis for death may assist decision-making regarding the transfer of the patients to hospitals more capable of handling their condition, admission to the intensive care unit, and adequate support and specific treatment.     

Zinc kinetics in insulin-dependent diabetes mellitus patients

Zinc has an important role in the control of carbohydrate metabolism, and diabetic patients are at risk for zinc deficiency. However, there are conflicting data concerning nutritional zinc status. In order to investigate this topic, 10 normal and 10 insulin-dependent diabetic patients were studied following venous zinc tolerance test. Our results found no evidence of zinc deficiency or of changes on the kinetic parameters of zinc in patients with insulin-dependent diabetes mellitus following a venous zinc tolerance test.     

Lignans from leaves,seedlings and micropropagated plants of Rollinia mucosa (Jacq.) Baill. – Annonaceae

Rollinia mucosa produces furofuranic lignans (magnolin, epiyangambin, yangambin) that are antagonists of platelet-activating factor (PAF). The biosynthetic capacity and the potential for the accumulation of furofuranic lignans, including epieudesmin, of the plants cultured both in vivo and in vitro conditions were evaluated. The production and the pattern of lignans accumulated were dependent on the origin of the plant material and the plant organ. The major accumulation of lignans was observed in leaves. In the mature leaves of in vivo grown seedlings magnolin and yangambin predominated, in contrast to leaves from in vitro propagated plants that presented epiyangambin as the major lignan. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cryopreservation of caprine ovarian tissue using dimethylsulphoxide and propanediol

The caprine ovary is a rich source of potentially viable immature oocytes enclosed in preantral follicles (PF). Previous experiments showed that these oocytes can be successfully cryopreserved in ovarian tissue of several species. However, until now, no information about the caprine PF cryopreservation is available in the literature. The aim of the present research was to evaluate the structural and ultrastructural characteristics of caprine PF after treatment and cryopreservation of ovarian tissue with 1.5 and 3 M dimethylsulphoxide (DMSO) and propanediol (PROH). One fragment of ovarian tissue was immediately fixed for histological examination and ultrastructural analysis, after slaughter (control). Four fragments were equilibrated at 20 degrees C/20 min in 1.8 ml of minimum essential medium (MEM) containing 1.5 or 3 M DMSO or PROH for the toxicity test, and the other four fragments were slowly frozen in each cryoprotectant at the concentrations previously described. After toxicity test and freezing/thawing procedures, the ovarian fragments were fixed for histological examination. The results showed that after toxicity test and cryopreservation of ovarian tissue using both cryoprotectants, the percentage of normal PF was less (P < 0.05) as compared with the control group. The present study revealed that the percentage of normal PF after toxicity test and cryopreservation in 1.5 M DSMO was significantly greater (P < 0.05) as compared with results obtained with 3 M DMSO or 1.5 and 3 M PROH. This result was confirmed by transmission electron microscopy, which showed that the PF were preserved in a higher quality state with 1.5 M DMSO. In conclusion, the present study demonstrated that caprine PF can be cryopreserved in ovarian tissue using 1.5 M DMSO.     

Effects of density and predation risk on leaf litter processing by Phylloicus sp.

The allochthonous detritus that accumulates in the substrate of streams is used by aquatic invertebrate shredders for shelter and food. Shredders are considered rare in tropical systems, and little information is available about the role of density effects and predation risk (associated with the perception of predators by prey) in relationship to the resources used by these organisms. The aim of this study was to examine experimentally the effects of increased predation risk and of the density of Phylloicus sp. (i.e. of two types of biological relationships) on the processing of the leaf litter of Nectandra megapotamica (Spreng.) Mez. Phylloicus sp. can use leaf litter for case building and as a food resource. The density effect was measured using four treatments that differed only in the number of individuals (one, two, three or four). A second experiment with five treatments was performed to test the risk of non‐lethal predation on detritus consumption (shelter and food) by Phylloicus sp. (T1: Caddisfly; T2: Mayfly; T3: Astyanax sp./fish; T4: Damselflies; T5: Stonefly). A single Phylloicus and one other organism (a potential predator blocked with 0.5 mm fine mesh) were placed in each tank (0.002 m³ volume). We observed a negative effect of density on per capita litter consumption (experiment 1). The low density of Phylloicus may be a natural factor that decreases intraspecific competition. In the presence of fish, Phylloicus showed the lowest amount of litter processing observed in the experiment, indicating top‐down control (experiment 2). In treatments that involved the presence of invertebrates (non‐predatory and predatory), Phylloicus showed the highest amount and an intermediate amount of leaf litter processing, respectively (experiment 2). This observation also suggests that the predation effect is more probable for specific predator–prey pairs. Population density and predation risk in Phylloicus may be important factors controlling leaf litter processing.     

Distributed File System Virtualization Techniques Supporting On-Demand Virtual Machine Environments for Grid Computing

This paper presents a data management solution which allows fast Virtual Machine (VM) instantiation and efficient run-time execution to support VMs as execution environments in Grid computing. It is based on novel distributed file system virtualization techniques and is unique in that: (1) it provides on-demand cross-domain access to VM state for unmodified VM monitors; (2) it enables private file system channels for VM instantiation by secure tunneling and session-key based authentication; (3) it supports user-level and write-back disk caches, per-application caching policies and middleware-driven consistency models; and (4) it leverages application-specific meta-data associated with files to expedite data transfers. The paper reports on its performance in wide-area setups using VMware-based VMs. Results show that the solution delivers performance over 30% better than native NFS and with warm caches it can bring the application-perceived overheads below 10% compared to a local-disk setup. The solution also allows a VM with 1.6 GB virtual disk and 320 MB virtual memory to be cloned within 160 seconds for the first clone and within 25 seconds for subsequent clones. Ming Zhao is a PhD candidate in the department of Electrical and Computer Engineering and a member of the Advance Computing and Information Systems Laboratory, at University of Florida. He received the degrees of BE and ME from Tsinghua University. His research interests are in the areas of computer architecture, operating systems and distributed computing. Jian Zhang is a PhD student in the Department of Electrical and Computer Engineering at University of Florida and a member of the Advance Computing and Information Systems Laboratory (ACIS). Her research interest is in virtual machines and Grid computing. She is a member of the IEEE and the ACM. Renato J. Figueiredo received the B.S. and M.S. degrees in Electrical Engineering from the Universidade de Campinas in 1994 and 1995, respectively, and the Ph.D. degree in Electrical and Computer Engineering from Purdue University in 2001. From 2001 until 2002 he was on the faculty of the School of Electrical and Computer Engineering of Northwestern University at Evanston, Illinois. In 2002 he joined the Department of Electrical and Computer Engineering of the University of Florida as an Assistant Professor. His research interests are in the areas of computer architecture, operating systems, and distributed systems.     

An improved method to obtain antigen-excreting Toxocara canis larvae

Toxocara canis is a dog helminth which causes visceral larva migrans (VLM) when infecting humans as a larva. The infection is demonstrated by detecting IgG antibodies against excretory-secretory larval antigens (ESLA) in serum by ELISA. The production of ESLA involves the collection of adult worms from dog puppy stools, the separation of eggs from dissected uteri, and the in vitro growing of egg-derived larvae, following the time-consuming and laborious protocol described by De Savigny [De Savigny, D.H., 1975. In vitro maintenance of T. canis larvae and a simple method for the production of Toxocara ES antigen for the uses in serodiagnostic tests for visceral larva migrans. Journal of Parasitology 61, 781-782]. In this work, an improved protocol for obtaining T. canis larvae is described. The modifications proposed improved the efficiency of the original De Savigny method in three ways: (i) increasing the parasite yield up to five fold, (ii) improving the larval purity, and (iii) markedly reducing the execution time of the protocol.