Developing a workable infection control policy for the dental laboratory

An enforced infection control policy in a laboratory will reduce occupational exposure to blood-borne pathogens and other infectious diseases and protect the dental laboratory personnel from exposure to infective disease. An outline of a workable laboratory infection control policy based on "Occupational Exposure to Bloodborne Pathogens" requirements is presented.     

Chemopreventive effects of alpha-santalol on skin tumor development in CD-1 and SENCAR mice.

Studies from our laboratory have indicated skin cancer chemopreventive effectsof sandalwood oil in CD-1 mice. The purpose of this investigation was to study the skin cancer chemopreventive effects of alpha-santalol, a principal component of sandalwood oil in CD-1 and SENCAR mice. alpha-Santalol was isolated from sandalwood oil by distillation under vacuum and characterized by nuclear magnetic resonance and gas chromatography-mass spectrometry. Chemopreventive effects of alpha-santalol were determined during initiation and promotion phase in female CD-1 and SENCAR mice. Carcinogenesis was initiated with 7,12-dimethylbenz(a)anthracene and promoted with 12-O-tetradecanoylphorbol-13-acetate (TPA). The effects of alpha-santalol treatment on TPA-induced epidermal ornithine decarboxylase (ODC) activity and (3)H-thymidine incorporation in epidermal DNA of CD-1 and SENCAR mice were also investigated. alpha-Santalol treatment during promotion phase delayed the papilloma development by 2 weeks in both CD-1 and SENCAR strains of mice. alpha-Santalol treatment during promotion phase significantly (P < 0.05) decreased the papilloma incidence and multiplicity when compared with control and treatment during initiation phase during 20 weeks of promotion in both CD-1 and SENCAR strains of mice. alpha-Santalol treatment resulted in a significant (P < 0.05) inhibition in TPA-induced ODC activity and incorporation of (3)H-thymidine in DNA in the epidermis of both strains of mice. alpha-Santalol significantly prevents papilloma development during promotion phase of 7,12-dimethylbenz(a)anthracene-TPA carcinogenesis protocol in both CD-1 and SENCAR mice, possibly by inhibiting TPA-induced ODC activity and DNA synthesis. alpha-Santalol could be an effective chemopreventive agent for skin cancer. Additional experimental and clinical studies are needed to investigate the chemopreventive effect of alpha-santalol in skin cancer.     

Human immunodeficiency virus case detection and antiretroviral therapy enrollment among children below and above 18 months old: A comparative analysis from Cameroon

While pediatric human immunodeficiency virus (HIV) testing has been more focused on children below 18 months through prevention of mother to child transmission of HIV (PMTCT), the yield of this approach remains unclear comparatively to testing children above 18 months through routine provider-initiated testing and counselling (PITC). This study aimed at assessing and comparing the HIV case detection and antiretroviral therapy (ART) enrolment among children below and above 18 months of age in Cameroon. This information is required to guide the investments in HIV testing among children and adolescents.We conducted a cross-sectional study where we invited parents visiting or receiving HIV care in 3 hospitals to have their children tested for HIV. HIV testing was done using polymerase chain reaction (PCR) and antibody rapid tests for children <18 months and those ≥18 months, respectively. We compared HIV case detection and ART initiation between the 2 subgroups of children and this using Chi-square test at 5% significant level.A total of 4079 children aged 6 weeks to 15 years were included in the analysis. Compared with children <18 months, children group ≥18 months was 4-fold higher among those who enrolled in the study (80.3% vs 19.7%, P < .001); 3.5-fold higher among those who tested for HIV (77.6% vs 22.4%, P < .001); 6-fold higher among those who tested HIV+ (85.7% vs 14.3%, P = .24), and 11-fold higher among those who enrolled on ART (91.7% vs 8.3%, P = .02).Our results show that 4 out of 5 children who tested HIV+ and over 90% of ART enrolled cases were children ≥18 months. Thus, while rolling out PCR HIV testing technology for neonates and infants, committing adequate and proportionate resources in antibody rapid testing for older children is a sine quo none condition to achieve an acquired immunodeficiency syndrome (AIDS)-free generation.     

Risk factors for pre-eclampsia in Mulago Hospital, Kampala, Uganda

Objective Pre‐eclampsia contributes significantly to maternal, foetal and neonatal morbidity and mortality. The risk factors for pre‐eclampsia have not been well documented in Uganda. In this paper, we describe the risk factors for pre‐eclampsia in women attending antenatal clinics at Mulago Hospital, Kampala. Methods This casecontrol study was conducted from 1st May 2008 to 1st May 2009. 207 women with pre‐eclampsia were the cases, and 352 women with normal pregnancy were the controls. The women were 15–39 years old, and their gestational ages were 20 weeks or more. They were interviewed about their socio‐demographic characteristics, past medical history and, their past and present obstetric performances. Results The risk factors were low plasma vitamin C (OR 3.19, 95% CI: 1.54–6.61), low education level (OR 1.67, 95% CI: 1.12–2.48), chronic hypertension (OR 2.29, 95% CI 1.12–4.66), family history of hypertension (OR 2.25, 95% CI: 1.53–3.31) and primiparity (OR 2.76, 95% CI: 1.84–4.15) and para≥5 (3.71, 95% CI:1.84–7.45). Conclusion The risk factors identified are similar to what has been found elsewhere. Health workers need to identify women at risk of pre‐eclampsia and manage them appropriately so as to prevent the maternal and neonatal morbidity and mortality associated with this condition.     

Human defensin alpha-1 causes Trypanosoma cruzi membrane pore formation and induces DNA fragmentation, which leads to trypanosome destruction

Human defensins play a fundamental role in the initiation of innate immune responses to some microbial pathogens. Here we show that human defensin alpha-1 displays a trypanocidal role against Trypanosoma cruzi, the causative agent of Chagas' disease. The toxicity of human defensin alpha-1 against T. cruzi is mediated by membrane pore formation and the induction of nuclear and mitochondrial DNA fragmentation, leading to trypanosome destruction. Exposure of trypomastigote and amastigote forms of T. cruzi to defensin alpha-1 significantly reduced parasite viability in a peptide concentration-dependent and saturable manner. The toxicity of defensin alpha-1 against T. cruzi is blocked by anti-defensin alpha-1 immunoglobulin G. Electron microscopic analysis of trypomastigotes exposed to defensin alpha-1 revealed pore formation in the cellular and flagellar membranes, membrane disorganization, and blebbing as well as cytoplasmic vacuolization. Furthermore, human defensin alpha-1 enters the trypanosome when membrane pores are present and is associated with later intracellular damage. Trypanosome membrane depolarization abolished the toxicity of defensin alpha-1 against the parasite. Preincubation of trypomastigotes with defensin alpha-1 followed by exposure to human epithelial cells significantly reduced T. cruzi infection in these cells. Thus, human defensin alpha-1 is an innate immune molecule that causes severe toxicity to T. cruzi and plays an important role in reducing cellular infection. This is the first report showing that human defensin alpha-1 causes membrane pore formation in a human parasite, leading to trypanosome destruction.     

The role of interstitial macrophages in nephropathy of type 2 diabetic db/db mice

Diabetic nephropathy is associated with interstitial macrophage infiltrates, but their contribution to disease progression is unclear. We addressed this question by blockade of chemokine receptor (CCR)1 because CCR1 mediates the macrophage recruitment to the renal interstitium. In fact, when CCR1 was blocked with BL5923, a novel orally available CCR1 antagonist, the interstitial recruitment of ex vivo labeled macrophages was markedly decreased in uninephrectomized male db/db mice with advanced diabetic nephropathy. Likewise, BL5923 (60 mg/kg, twice a day) orally administered from months 5 to 6 of life reduced the numbers of interstitial macrophages in uninephrectomized db/db mice. This was associated with reduced numbers of Ki-67 proliferating tubular epithelial and interstitial cells, tubular atrophy, and interstitial fibrosis in uninephrectomized db/db mice. Glomerular pathology and proteinuria were not affected by the CCR1 antagonist. BL5923 reduced renal mRNA expression of Ccl2, Ccr1, Ccr2, Ccr5, transforming growth factor-beta1, and collagen I-alpha1 when compared with untreated uninephrectomized male db/db mice of the same age. Thus, we identified a previously unrecognized role for interstitial macrophages for tubulointerstitial injury, loss of peritubular microvasculature, interstitial inflammation, and fibrosis in type 2 diabetic db/db mice. These data identify oral treatment with the CCR1 antagonist BL5923 as a potential therapy for late-stage diabetic nephropathy.     

Influence of Incubation Period on Callus Tissues for Plant Regeneration in Ophiorrhiza pectinata Arn. Through Somatic Embryogenesis

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Ophiorrhiza pectinata Arn. is an important medicinal plant reported to contain camptothecin which is used for...     

Dynamical facilitation governs glassy dynamics in suspensions of colloidal ellipsoids

One of the greatest challenges in contemporary condensed matter physics is to ascertain whether the formation of glasses from liquids is fundamentally thermodynamic or dynamic in origin. Although the thermodynamic paradigm has dominated theoretical research for decades, the purely kinetic perspective of the dynamical facilitation (DF) theory has attained prominence in recent times. In particular, recent experiments and simulations have highlighted the importance of facilitation using simple model systems composed of spherical particles. However, an overwhelming majority of liquids possess anisotropy in particle shape and interactions, and it is therefore imperative to examine facilitation in complex glass formers. Here, we apply the DF theory to systems with orientational degrees of freedom as well as anisotropic attractive interactions. By analyzing data from experiments on colloidal ellipsoids, we show that facilitation plays a pivotal role in translational as well as orientational relaxation. Furthermore, we demonstrate that the introduction of attractive interactions leads to spatial decoupling of translational and rotational facilitation, which subsequently results in the decoupling of dynamical heterogeneities. Most strikingly, the DF theory can predict the existence of reentrant glass transitions based on the statistics of localized dynamical events, called excitations, whose duration is substantially smaller than the structural relaxation time. Our findings pave the way for systematically testing the DF approach in complex glass formers and also establish the significance of facilitation in governing structural relaxation in supercooled liquids.The transformation of liquids into glasses is as ubiquitous as it is enigmatic. From the formation of obsidian during volcanic eruptions (1) and fabrication of superstrong metallic glasses (2) to exotic forms of slow dynamics in crystals of colloidal dimers (3) and Janus particles (4), glass formation pervades nature, industry, and academia. A vast majority of molecular glass-forming materials exhibit anisotropy in shape and interparticle interactions, which often has a profound influence on their glassy dynamics. The rapidly expanding repertoire of chemists has made it possible to design colloidal particles of desired shape and interactions that can serve as realistic experimental analogs of these molecular liquids (5). By contrast, prominent theories like the Adam–Gibbs (6) theory, random first-order transition (RFOT) theory (7, 8), and the dynamical facilitation (DF) theory (9, 10) have been tested predominantly on spherical glass formers with isotropic interactions, which exhibit gross features of glassy dynamics, but fail to capture the nuances of vitrification in complex systems.The discovery of growing static (11–16) and dynamic (17–21) length scales appears to support the thermodynamic perspective of the Adam–Gibbs and RFOT theories. However, the growth in static length scales over the dynamical range accessible to numerical simulations is often minuscule and much smaller than the corresponding growth in dynamic length scales (21, 22). This renders any causal connection between growing static length scales and growing timescales doubtful (22). Moreover, recent simulations (23) and colloid experiments (24) have shown that growing dynamical correlations in the form of string-like cooperative motion emerge naturally within the purely kinetic approach of the DF theory. To compound matters further, facilitation is present even within the RFOT framework, albeit as a consequence of slow dynamics rather than a cause (25). Thus, although DF has been shown to exist (23, 24, 26–29), its relative importance as a mechanism of structural relaxation is still debated (30–32). The application of the DF approach to complex glass formers will therefore not only enhance our understanding of glass transitions in these systems, but also help ascertain the relevance of facilitation in governing structural relaxation.Here, we apply the DF theory to elucidate glass formation in suspensions of colloidal ellipsoids with repulsive as well as attractive interactions. The DF theory claims that structural relaxation in glass-forming liquids proceeds via a process known as dynamical facilitation, whereby localized mobile regions, termed excitations, mediate motion in neighboring regions in a manner that conserves mobility (9, 10). We first show that the notions of localized excitations and facilitated dynamics can be extended even to orientational relaxation. Next, we demonstrate that the spatial decoupling of dynamical heterogeneities (DHs) observed in colloid experiments stems from the spatial decoupling of rotational and translational facilitation. Most importantly, the DF theory can predict the existence of recently observed reentrant glass transitions (33) from the density dependence of the concentration of excitations. Our findings not only highlight the importance of facilitated dynamics in anisotropic glass formers but also reinforce the claim that, in the broader context of the glass transition, facilitation dominates structural relaxation.     

Safety and efficacy of an aroA-deleted live vaccine against avian colibacillosis in a multicentre field trial in broilers in Morocco

The safety and efficacy of an aroA-deleted live vaccine against avian colibacillosis (Poulvac^® E. coli) was evaluated in broilers in a multicentre field trial. The trial sites consisted of 18 paired bird houses (randomly assigned to either the vaccination or the control treatment groups) located in 15 farms in three different regions of Morocco. A field dose of vaccine was administered on day of hatch by the spray route. Both clinical and performance parameters were compared between vaccinated and control groups, in which the experimental unit was defined as the individual bird house. No adverse reactions attributable to the vaccine were observed throughout the study. Non-inferiority of the vaccinated bird houses versus the control houses during a 2-week period post vaccination was statistically demonstrated for mortality and average daily weight gain. Vaccine efficacy was confirmed based on significant differences between vaccinated and unvaccinated groups measured for the full duration of the trial, including colibacillosis-like lesions observed at slaughter (1.7 versus 3.5%; P = 0.0054), total mortality (9.3 versus 10.3%; P = 0.0203), average daily weight gain (47.8 versus 46.2 g/day; P = 0.0006), average number of antibiotic treatment days (0.5 versus 2.0; P = 0.0008) and percentage of the birds that was marketed (90.0 versus 89.0%; P = 0.0309). In conclusion, the vaccine was demonstrated to be both safe and efficacious under field conditions.