Compliance with occupational exposure risk management procedures in a dental school setting.

Background The Dental Institute at King's College London has recently implemented changes focusing on infection control, including safety needle provision, personal protective equipment campaigns, mandatory lectures and formal assessment for students. We explored the effect of these changes over a five-year period.Methods We observed 49 clinical consultations in 2010 and 50 in 2014, examining clinician attire, personal protective equipment, dental operatory management, sharps hazards and aseptic technique.Results One hundred percent of operators wore gloves, apron and masks, 94% wore eye protection, 98% had uncovered wrists and 88% had tidy hair. Ninety-four percent wore safe shoes, 86% were of appropriate material, and 70-82% demonstrated correct zoning technique. Safe sharps bin placement improved from 78% to 100%, 92% were not overfilled, and 96% were free from protruding items. Sixty-eight percent of bays were appropriately barrier wrapped, 78-88% were kept tidy and 96% were free of items that could have been disposed of immediately following use. Ninety to ninety-eight percent of ultrasonic tips and 64% of burs were removed from handpieces when not in use.Conclusion Dental healthcare workers are at risk of significant occupational exposures, which can be minimised by technological advances, implementation of best practice guidelines, optimisation of the clinical working environment and reinforcement of infection control policy.

Mass transport effects on the kinetics of nitrobenzene reduction by iron metal.

To evaluate the importance of external mass transport on the overall rates of contaminant reduction by iron metal (Fe0), we have compared measured rates of surface reaction for nitrobenzene (ArNO2) to estimated rates of external mass transport in a permeable reactive barrier (PRB). The rate of surface reaction was measured at a polished Fe0 rotating disk electrode (RDE) in an electrochemical cell, and the rate of mass transport was estimated from a correlation for mass transport in packed-bed reactors. The kinetics of ArNO2 reduction were studied in pH 8.4 borate buffer at a potential below which an oxide film would form. The cathodic current measured in this system was dependent on the electrode rotation rate, and the measured first-order heterogeneous rate coefficient for surface reaction [krxn = (1.7 +/- 0.2) x 10(-3) cm s-1] was about 10 times faster than the first-order mass transport rate coefficient (kmt approximately 2 x 10(-4) cm s-1) estimated for PRBs. The similarity between rates of surface reaction and mass transport suggest that it may be important to consider mass transport processes in the design of PRBs for contaminants such as nitroaromatics that are highly reactive with Fe0.

Poor education linked with teen pregnancies.

PIP: Two reports concerning socioeconomic factors associated with adolescent pregnancy have been released: a study from the NHS Centre for Reviews and Dissemination at the University of York; and a survey from the Alan Guttmacher Institute, a non-profit reproductive health analysis organization in New York. The first report associates truancy, low academic achievement and poor sex education with the high pregnancy rate in Britain among women 15-19 years old. The rate is the highest in western Europe, although the rate of conceptions in Britain among women 16-19 years old has declined since 1990 and is currently 56.8 per 1000. For girls under 16 years old, a group targeted by the British government's Health of the Nation strategy to achieve a conception rate of 4.8 per 1000 by the year 2000, the rate has remained steady for the last 20 years and stands at 8.3 per 1000. The report calls for better school-based sex education and for improved access to confidential contraceptive services for young people. The second report, an international survey, shows that the number of teenage pregnancies worldwide is declining (although 15 million babies, 10% unplanned, are born annually to teenage mothers), and that women with a higher education level tend to delay marriage and childbearing. A figure compares the percentages of women 20-24 years old who gave birth by age 20 for 4 educational levels (less than 7 years, greater than or equal to 7 years, less than 12 years, greater than or equal to 12 years) for Ghana, Kenya, Zimbabwe, Bangladesh, Egypt, Indonesia, the Philippines, Bolivia, Brazil, Columbia, Mexico, France, Japan, and the United States. Teenage pregnancy in both reports was associated with poor social, economic, and health outcomes for mother and child. According to the second report, the risk of maternal death during childbirth is 2-4 times greater for mothers 17 and younger, in comparison to mothers age 20 and older. Dr. Kathleen Kiernan, a senior research fellow at the London School of Economics, blames Britain's high adolescent pregnancy rate on an educational system that allows 16-year olds to leave school for a low-paying job and to take on adult roles at an earlier age than their European counterparts.^ieng

Diminished interferon-gamma and lymphocyte proliferation in neonatal and postpartum primary herpes simplex virus infection.

Interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production and lymphocyte proliferation in response to herpes simplex virus (HSV) antigen were assessed in 13 neonates and 3 parturient women with primary HSV infection. In comparison with 9 nonparturient adults, the neonates and parturient women showed significantly (P less than .01) diminished HSV antigen-stimulated lymphocyte proliferation and IFN-gamma production in the first 3-6 weeks after onset of infection. TNF alpha production did not differ significantly among HSV-infected groups. The impairment in neonatal cellular immunity was due, at least in part, to a specific deficit in response to HSV antigen. Lymphocyte proliferation and TNF alpha production in response to the mitogen concanavalin A (ConA) were comparable in adults and infants, but ConA-stimulated IFN-gamma production in infants was diminished throughout the study period. In contrast, HSV antigen-stimulated IFN-gamma production was comparable in infants and adults after 6 weeks. Not all patients with diminished cellular immune responses to HSV antigen manifested severe clinical disease. Nevertheless, patients with significant clinical morbidity had diminished cellular immune responses to HSV antigen. These results suggest that delayed acquisition of antigen-specific cellular immunity in primary HSV infection predisposes to more severe clinical disease.

Regulation of tumor necrosis factor/cachectin and IL-1 secretion in human mononuclear phagocytes.

To determine whether the production and secretion of TNF and IL-1 by human mononuclear phagocytes could be independently modulated, we examined secretion of TNF and IL-1 by fresh monocytes and monocytes pretreated with IFN-gamma or granulocyte macrophage CSF before LPS stimulation. TNF and IL-1 secretion were in part differentially modulated. Fresh monocytes secreted large amounts of TNF and IL-1 after LPS stimulation and less than 6% as much without LPS. The capacity to secrete TNF in response to LPS decreased slightly in cultured monocytes but was markedly augmented by IFN-gamma (approximately five-fold more than fresh monocytes). In contrast, cultured monocytes secreted less than 5% as much IL-1 as fresh monocytes and, although augmented by IFN-gamma, IL-1 secretion remained much less than by fresh monocytes. These differences in modulation were reflected by differences in the molecular mechanisms regulating TNF and IL-1 secretion. TNF secretion was regulated primarily by changes in the duration of increased transcription and by an apparent increase in translation or protein stability in response to LPS; greater than 95% TNF produced was secreted under all conditions. In contrast, the changes in IL-1 secretion reflected primarily post-transcriptional regulation of IL1-alpha mRNA, transcriptional and post-transcriptional regulation of IL-1 beta mRNA and a decrease in the fraction of IL-1 secreted by cultured compared with fresh monocytes (10 and 60%, respectively). Changes in translational efficiency or protein processing or stability appeared not to be important mechanisms regulating IL-1 secretion. Additional evidence that TNF and IL-1 can be differentially modulated was the selective decrease in TNF secretion and the failure of IFN-gamma to enhance TNF secretion by cultured monocytes from neonates, whereas results for IL-1 were similar with adult and neonatal monocytes. Results with tissue macrophages were similar to those with cultured monocytes. These results indicate that TNF and IL-1 production and secretion by mononuclear phagocytes can be differentially modulated, reflecting in part different mechanisms of regulation; this may allow them to play partially independent roles in the host immune response.

Decreased production of interferon-gamma by human neonatal cells. Intrinsic and regulatory deficiencies.

Human neonatal lymphocytes produced little macrophage activation factor in response to mitogens. This correlated with decreased production of interferon-gamma (IFN gamma): adult lymphokines contained 894.2 +/- 177.1 U/ml, whereas neonatal cord and peripheral lymphokines contained 66.9 +/- 17.0 and 116.7 +/- 29.6 U/ml by bioassay. Results by radioimmunoassay (RIA) for IFN gamma were similar. In contrast, the interleukin 2 content of cord lymphokines was greater (P less than 0.01) and that of neonatal peripheral blood lymphokines similar to that of adults. Interleukin 1 production and interleukin 2 receptor expression and affinity were similar for adult and neonatal cells. Interleukins 1 and 2 in amounts comparable to those in adult lymphokines did not increase production of macrophage activation factor or IFN gamma by neonatal cells. Neonatal cells did not contain intracellular IFN or degrade exogenous IFN. Excess suppressor activity was not found in neonatal cultures. Addition of IFN alpha, 10,000-50,000 U/ml of interleukin 2 or phorbol myristate acetate (PMA) to cord mononuclear cells or of adult monocytes or PMA to cord T cells increased IFN gamma production compared to cells stimulated with concanavalin A (ConA) alone. Nevertheless, under optimal conditions (T cells + PMA + Con A), adult cells produced much more IFN gamma (1,360 +/- 261 U/ml by RIA) than cord cells (122 +/- 37 U/ml). Staphylococcal enterotoxin A (SEA) stimulated cord cell IFN gamma production at low cell densities; nevertheless, adult cells produced more IFN in response to SEA 1,341 +/- 350 U/ml) than cord cells (350 +/- 33 U/ml). Decreased production of IFN gamma by neonatal cells appears to be due both to differences in their intrinsic capacity to produce IFN gamma and to differences in regulatory mechanisms.

Activation of neonatal and adult human macrophages by alpha, beta, and gamma interferons.

Increasing evidence suggests that gamma interferon (IFN-gamma) is the major or sole factor in human lymphokines which activates blood monocyte-derived macrophages (M phi) to inhibit or kill Toxoplasma gondii and certain other intracellular pathogens. In the current studies, we found that IFN-gamma effectively activated tissue M phi from adults (peritoneal M phi) and from newborns (placental M phi) as well as blood-derived M phi from adults and from newborns to kill or to inhibit the replication of T. gondii. Results with purified and recombinant IFN-gamma and with adult and newborn M phi were similar. IFN-gamma-treated M phi were equally or more active against T. gondii than were freshly isolated monocytes and M phi. Recombinant IFN-alpha A and IFN-beta were less effective than IFN-gamma. IFN-gamma also inhibited survival and replication of T. gondii in WISH cells more effectively than did IFN-alpha and IFN-beta. These findings are consistent with an important role for IFN-gamma in the control of Toxoplasma infection and indicate that the anti-Toxoplasma activity of resting and IFN-gamma-activated adult and neonatal M phi is similar. The increased susceptibility of neonates to T. gondii is not due to a defect in M phi effector function.