Neurological symptoms among dental assistants: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Dental assistants help the dentist in preparing material for filling teeth. Amalgam was the filling material mostly commonly used in Norway before 1980, and declined to about 5% of all fillings in 2005. Amalgam is usually an alloy of silver, copper, tin and mercury. Copper amalgam, giving particularly high exposure to mercury was used in Norway until 1994. Metallic mercury is neurotoxic. Few studies of the health of dental assistants exist, despite their exposure to mercury. There are questions about the existence of possible chronic neurological symptoms today within this working group, due to this exposure. The aim of this study was to compare the occurrence of neurological symptoms among dental assistants likely to be exposed to mercury from work with dental filling material, compared to similar health personnel with no such exposure.</p> <p>Methods</p> <p>All dental assistants still at work and born before 1970 registered in the archives of a trade union in Hordaland county of Norway were invited to participate (response rate 68%, n = 41), as well as a similar number of randomly selected assistant nurses (response rate 87%, n = 64) in the same age group. The participants completed a self-administered, mailed questionnaire, with questions about demographic variables, life-style factors, musculoskeletal, neurological and psychosomatic symptoms (Euroquest).</p> <p>Results</p> <p>The dental assistants reported significant higher occurrence of neurological symptoms; psychosomatic symptoms, problems with memory, concentration, fatigue and sleep disturbance, but not for mood. This was found by analyses of variance, adjusting for age, education, alcohol consumption, smoking and personality traits. For each specific neurological symptom, adjusted logistic regression analyses were performed, showing that these symptoms were mainly from arms, hands, legs and balance organs.</p> <p>Conclusion</p> <p>There is a possibility that the higher occurrence of neurological symptoms among the dental assistants may be related to their previous work exposure to mercury amalgam fillings. This should be studied further to assess the clinical importance of the reported symptoms.</p

Measurement and calculation of levitation forces between magnets and granular superconductors

Recent developments indicate that exploitation of the phenomenon of magnetic levitation may become one of the most important near-term applications of high-T(sub c) superconductivity. Because of this, the interaction between a strong permanent magnet(PM) and bulk high-T(sub c) superconductor (HTSC) is currently a subject of much interest. We have studied central features of the mechanics of PM-HTSC systems of simple geometries. Here we report experimental results for the components of the levitation force, their associated stiffness and mechanical ac-loss. To analyze the observed behavior a theoretical framework based on critical-state considerations is developed. It will be shown that all the mechanical properties can be explained consistently at a quantitative level wing a minimum of model parameters

Surface properties correlate to the digestibility of hydrothermally pretreated lignocellulosic Poaceae biomass feedstocks

Additional file 1: Figures S1–S12. 13C-1H HSQC (heteronuclear single quantum coherence) spectra of untreated (raw) and hydrothermally pretreated (log R 0 = 3.65, 3.83 and 3.97) corn stover, Miscanthus × giganteus stalks and wheat straw. Figure S13. Phenylcoumaran structure. Figures S14–S16. Selected ATR-FTIR spectra each representing sample from untreated (raw) and hydrothermally pretreated (log R 0 = 3.65, 3.83 and 3.97) corn stover, Miscanthus × giganteus stalks and wheat straw. Figures S17–S30. Scatter plot of surface and bulk chemical composition with glucose release and wettability test of hydrothermally pretreated (log R 0 = 3.65, 3.83 and 3.97) corn stover, Miscanthus × giganteus stalks and wheat straw

Thin superconducting disk with B-dependent Jc: Flux and current distributions

The critical state in a superconducting thin circular disk with an arbitrary magnetic field dependence of the critical sheet current, Jc(B), is analyzed. With an applied field Ba perpendicular to the disk, a set of coupled integral equations for the flux and current distributions is derived. The equations are solved numerically, and flux and current profiles are presented graphically for several commonly used Jc(B) dependences. It is shown that for small Ba the flux penetration depth can be described by an effective Bean model with a renormalized Jc entering the leading term. We argue that these results are qualitatively correct for thin superconductors of any shape. The results contrast the parallel geometry behavior, where at small Ba the B-dependence of the critical current can be ignored.Comment: RevTeX, 7 pages including 8 figure

Unexplained chronic liver disease in Ethiopia: a cross-sectional study

BACKGROUND: Hepatitis B virus (HBV) infection is assumed to be the major cause of chronic liver disease (CLD) in sub-Saharan Africa. The contribution of other aetiological causes of CLD is less well documented and hence opportunities to modulate other potential risk factors are being lost. The aims of this study were to explore the aetiological spectrum of CLD in eastern Ethiopia and to identify plausible underlying risk factors for its development. METHODS: A cross-sectional study was undertaken between April 2015 and April 2016 in two public hospitals in Harar, eastern Ethiopia. The study population comprised of consenting adults with clinical and radiological evidence of chronic liver disease. The baseline evaluation included: (i) a semi-structured interview designed to obtain information about the ingestion of alcohol, herbal medicines and local recreational drugs such as khat (Catha edulis); (ii) clinical examination; (iii) extensive laboratory testing; and, (iv) abdominal ultrasonography. RESULTS: One-hundred-and-fifty patients with CLD (men 72.0%; median age 30 [interquartile range 25-40] years) were included. CLD was attributed to chronic HBV infection in 55 (36.7%) individuals; other aetiological agents were identified in a further 12 (8.0%). No aetiological factors were identified in the remaining 83 (55.3%) patients. The overall prevalence of daily khat use was 78.0%, while alcohol abuse, defined as > 20 g/day in women and > 30 g/day in men, was rare (2.0%). Histological features of toxic liver injury were observed in a subset of patients with unexplained liver injury who underwent liver biopsy. CONCLUSION: The aetiology of CLD in eastern Ethiopia is largely unexplained. The widespread use of khat in the region, together with histopathological findings indicating toxic liver injury, suggests an association which warrants further investigation

History of Foot Ulcer Increases Mortality Among Individuals With Diabetes: Ten-year follow-up of the Nord-Trøndelag Health Study, Norway

OBJECTIVE To compare mortality rates for individuals with diabetes with and without a history of foot ulcer (HFU) and with that for the nondiabetic population. RESEARCH DESIGN AND METHODS This population-based study included 155 diabetic individuals with an HFU, 1,339 diabetic individuals without an HFU, and 63,632 nondiabetic individuals who were all followed for 10 years with mortality as the end point. RESULTS During the follow-up period, a total of 49.0% of diabetic individuals with an HFU died, compared with 35.2% of diabetic individuals without an HFU and 10.5% of those without diabetes. In Cox regression analyses adjusted for age, sex, education, current smoking, and waist circumference, having an HFU was associated with more than a twofold (2.29 [95% CI 1.82–2.88]) hazard risk for mortality compared with that of the nondiabetic group. In corresponding analyses comparing diabetic individuals with and without an HFU, an HFU was associated with 47% increased mortality (1.47 [1.14–1.89]). Significant covariates were older age, male sex, and current smoking. After inclusion of A1C, insulin use, microalbuminuria, cardiovascular disease, and depression scores in the model, each was significantly related to life expectancy. CONCLUSIONS AN HFU increased mortality risk among community-dwelling adults and elderly individuals with diabetes. The excess risk persisted after adjustment for comorbidity and depression scores, indicating that close clinical monitoring might be warranted among individuals with an HFU, who may be particularly vulnerable to adverse outcomes. Hospital-based studies have shown that mortality rates in individuals with diabetic foot ulcers are about twice those observed in individuals with diabetes without foot ulcers (1,2). A diabetic foot ulcer reflects the presence of underlying pathological conditions, and the risk of recurrent ulcers is high (3,4). It has been suggested that the elevated mortality rate among individuals with diabetic foot ulcers is related to comorbid disease such as cardiovascular disease and nephropathy (5) or to psychological factors including depression (6). Although the mortality rate in individuals with diabetes is high, no large population-based studies have examined the impact on mortality of a history of foot ulcers (HFU) among individuals with diabetes. The purpose of this study was to compare mortality rates for individuals with diabetes reporting an HFU with those for individuals without an HFU and the nondiabetic population. These issues were investigated in the Nord-Trøndelag Health Study (HUNT 2), which includes a very large population-based sample of men and women from a well-defined geographic area. Participants with self-reported diabetes were well characterized with regard to their diabetes, and information on demographics, lifestyle, and prevalent disease including depression was available

Evaluation of immune responses in HIV infected patients with pleural tuberculosis by the QuantiFERON® TB-Gold interferon-gamma assay

<p>Abstract</p> <p>Background</p> <p>Diagnosis of tuberculous (TB) pleuritis is difficult and better diagnostic tools are needed. New blood based interferon-gamma (IFN-γ) tests are promising, but sensitivity could be low in HIV positive patients. The IFN-γ tests have not yet been validated for use in pleural fluid, a compartment with higher level of immune activation than in blood.</p> <p>Methods</p> <p>The QuantiFERON TB^®-Gold (QFT-TB) test was analysed in blood and pleural fluid from 34 patients presenting with clinically suspected pleural TB. Clinical data, HIV status and CD4 cell counts were recorded. Adenosine deaminase activity (ADA) analysis and TB culture were performed on pleural fluid.</p> <p>Results</p> <p>The patients were categorised as 'confirmed TB' (n = 12), 'probable TB' (n = 16) and 'non-TB' pleuritis (n = 6) based on TB culture results and clinical and biochemical criteria. The majority of the TB patients were HIV infected (82%). The QFT-TB in pleural fluid was positive in 27% and 56% of the 'confirmed TB' and 'probable TB' cases, respectively, whereas the corresponding sensitivities in blood were 58% and 83%. Indeterminate results in blood (25%) were caused by low phytohemagglutinin (PHA = positive control) IFN-γ responses, significantly lower in the TB patients as compared to the 'non-TB' cases (p = 0.02). Blood PHA responses correlated with CD4 cell count (r = 0.600, p = 0.028). In contrast, in pleural fluid indeterminate results (52%) were caused by high Nil (negative control) IFN-γ responses in both TB groups. Still, the Nil IFN-γ responses were lower than the TB antigen responses (p < 0.01), offering a conclusive test for half of the patients. We did not find any correlation between blood CD4 cell count and IFN-γ responses in pleural fluid.</p> <p>Conclusion</p> <p>The QFT-TB test in blood could contribute to the diagnosis of TB pleuritis in the HIV positive population. Still, the number of inconclusive results is too high to recommend the commercial QFT-TB test for routine use in pleural fluid in a TB/HIV endemic resource-limited setting.</p

A brain-infecting parasite impacts host metabolism both during exposure and after infection is established

Metabolic costs associated with parasites should not be limited to established infections. Even during initial exposure to questing and attacking parasites, hosts can enact behavioural and physiological responses that could also incur metabolic costs. However, few studies have measured these costs directly. Hence, little is known about metabolic costs arising from parasite exposure. Furthermore, no one has yet measured whether and how previous infection history modulates metabolic responses to parasite exposure. Here, using the California killifish Fundulus parvipinnis and its brain‐infecting parasite Euhaplorchis californiensis, we quantified how killifish metabolism, behaviour and osmoregulatory phenotype changed upon acute exposure to parasite infectious stages (i.e. cercariae), and with long‐term infection. Exposure to cercariae caused both naïve and long‐term infected killifish to acutely increase their metabolic rate and activity, indicating detection and response to parasite infectious stages. Additionally, these metabolic and behavioural effects were moderately stronger in long‐term infected hosts than naïve killifish, suggesting that hosts may develop learned behavioural responses, nociceptor sensitization and/or acute immune mechanisms to limit new infections. Although established infection altered the metabolic response to parasite exposure, established infection did not alter standard metabolic rate, routine metabolic rate, maximum metabolic rate, aerobic scope or citrate synthase enzyme activity. Unexpectedly, established infection reduced lactate dehydrogenase enzyme activity in killifish brains and relative Na+/K+‐ATPase abundance in gills, suggesting novel mechanisms by which E. californiensis may alter its hosts\u27 behaviour and osmoregulation. Thus, we provide empirical evidence that parasites can disrupt the metabolism of their host both during parasite exposure and after infection is established. This response may be modulated by previous infection history, with probable knock‐on effects for host performance, brain energy metabolism, osmoregulation and ecology. A free Plain Language Summary can be found within the Supporting Information of this article

The challenges of transdisciplinary knowledge production: from unilocal to comparative research

This reflective paper surveys the lessons learnt and challenges faced by the Mistra Urban Futures (MUF) research centre and its research platforms in Sweden, the UK, South Africa and Kenya in developing and deploying different forms of transdisciplinary co-production of knowledge. Considerable experience with a distinctive portfolio of such methods has been gained and reflective evaluation is now under way. While it is important to understand the local context within which each method has evolved, we seek to explain the potential for adaptation in diverse contexts so that such knowledge co-production methods can be more widely utilized. Furthermore, the current phase of MUF’s work is undertaking innovative comparative transdisciplinary co-production research across its research platforms. Since the specific local projects differ, systematic thematic comparison requires great care and methodological rigour. Transdisciplinary co-production is inherently complex, time consuming and often unpredictable in terms of outcomes, and these challenges are intensified when it is undertaken comparatively

A MANBA mutation resulting in residual beta-mannosidase activity associated with severe leukoencephalopathy: a possible pseudodeficiency variant

<p>Abstract</p> <p>Background</p> <p>β-Mannosidosis (OMIM 248510) is a rare inborn lysosomal storage disorder caused by the deficient activity of β-mannosidase, an enzyme encoded by a single gene (<it>MANBA</it>) located on chromosome 4q22-25. To date, only 20 cases of this autosomal recessive disorder have been described and 14 different <it>MANBA </it>mutations were incriminated in the disease. These are all null mutations or missense mutations that abolish β-mannosidase activity. In this study, we characterized the molecular defect of a new case of β-mannosidosis, presenting with a severe neurological disorder.</p> <p>Methods</p> <p>Genomic DNA was isolated from peripheral blood leukocytes of the patient to allow <it>MANBA </it>sequencing. The identified mutation was engineered by site-directed mutagenesis and the mutant protein was expressed through transient transfection in HEK293T cells. The β-mannosidase expression and activity were respectively assessed by Western blot and fluorometric assay in both leukocytes and HEK293T cells.</p> <p>Results</p> <p>A missense disease-associated mutation, c.1922G>A (p.Arg641His), was identified for which the patient was homozygous. In contrast to previously described missense mutations, this substitution does not totally abrogate the enzyme activity but led to a residual activity of about 7% in the patient's leukocytes, 11% in lymphoblasts and 14% in plasma. Expression studies in transfected cells also resulted in 7% residual activity.</p> <p>Conclusion</p> <p>Correlations between MANBA mutations, residual activity of β-mannosidase and the severity of the ensuing neurological disorder are discussed. Whether the c.1922G>A mutation is responsible for a yet undescribed pseudodeficiency of β-mannosidase is also discussed.</p