Mercury exposure of different origins among dentists and dental nurses

Mercury exposure was studied among dental personnel with the use of urinary mercury excretion rates and questionnaires. The study covered 314 dentists and dental nurses employed in public clinics and private practices in Stockholm. The obtained urinary mercury excretion rates were analyzed by stepwise regression for assigning them to different origins, such as environmental factors, number of amalgam surfaces, chewing of gum, kind of employment and profession, age, sex, amalgam handling time, and use of amalgam capsules. On the average the occupational contribution to the total urinary mercury excretion rate was small and of the same order as the contribution from their own amalgam fillings (approximately 2 micrograms of mercury/24 h). There were, however, individuals showing excretion rates close to the levels at which effects on the central nervous system and the kidneys have been reported.     

Evaluation of olestra in short-term genotoxicity assays

Olestra, a mixture of hexa-, hepta- and octa-esters formed from the reaction of sucrose with long-chain fatty acids, was evaluated for its genotoxic potential in the Salmonella/mammalian microsome test, the L5178Y thymidine kinase (TK+/-) mouse lymphoma assay, an unscheduled DNA synthesis assay in primary rat hepatocytes, and an in vitro cytogenetic assay in Chinese hamster ovary cells. The results indicated that olestra was non-genotoxic in these assays.     

Decreased infectivity in Borrelia burgdorferi strain B31 is associated with loss of linear plasmid 25 or 28-1

Previous reports indicated a correlation between loss of plasmids and decreased infectivity of Borrelia burgdorferi strain B31, suggesting that plasmids may encode proteins that are required for pathogenesis. In this study, we expand on this correlation. Using the B. burgdorferi genomic sequence, we designed primers specific for each plasmid, and by using PCR we catalogued 11 linear and 2 circular plasmids from 49 clonal isolates of a mid-passage B. burgdorferi strain B31, initially derived from infected mouse skin, and 20 clones obtained from mouse skin infected with a low-passage isolate of B. burgdorferi strain B31. Among the 69 clones analyzed, nine distinct genotypes were identified relative to wild-type B. burgdorferi strain B31. Among the nine clonal genotypes obtained, only the 9-kb circular plasmid (cp9), the 25-kb linear plasmid (lp25), and either the 28-kb linear plasmid 1 or 4 (lp28-1 and lp28-4, respectively) were missing, in different combinations. We compared the infectivity of the wild-type strain, containing all known B. burgdorferi plasmids, with those of single mutants lacking either lp28-1, lp28-4, or lp25 and a double mutant missing both cp9 and lp28-1. The infectivity data indicated that B. burgdorferi strain B31 cells lacking lp28-4 were modestly attenuated in all tissues analyzed, whereas samples missing lp25 were completely attenuated in all tissues, even at the highest inoculum tested. Isolates without lp28-1 infected the joint tissue yet were not able to infect other tissues as effectively. In addition, we have observed a selection in vivo in the skin, bladder, and joint for cells containing lp25 and in the skin and bladder for cells containing lp28-1, indicating that lp25 and lp28-1 encode proteins required for colonization and short-term maintenance in these mammalian tissues. In contrast, there was no selection in the joint for cells containing lp28-1, suggesting that genes on lp28-1 are not required for colonization of B. burgdorferi within the joint. These observations imply that the dynamic nature of the B. burgdorferi genome may provide the genetic heterogeneity necessary for survival in the diverse milieus that this pathogen occupies in nature and may contribute to tropism in certain mammalian host tissues.     

Cytogenetic and molecular cytogenetic studies of a case of interstitial deletion of proximal 15q

A 4-month-old child with multiple anomalies was determined to have an interstitial deletion of chromosome 15, i.e., del(15) (q12q14). The deletion appears not to be a typical deletion of 15q12 such as seen in Angelman and Prader-Willi syndromes, but appears to be more distal, involving either loss of all of 15q12 and part of 15q14, or part of 15q12 and most of 15q14. In either case, 15q13 is missing. Fluorescent in situ hybridization with probes for 15 centromere (D15Z), pericentromeric satellite sequences (D15Z1), and chromosome 15 painting probes shows the deleted chromosome to involve only 15 and no other acrocentric chromosome. Hybridization with probes for the AS and PWS loci (D15S11 and GABAB3, Oncor) show both sites to be intact in the deleted 15. The case is compared with two other reports with overlapping interstitial deletions of proximal 15q, neither of which shows typical features of Angelman or Prader-Willi syndromes.     

Urinary acetylated metabolites and N-acetyltransferase-2 genotype in human subjects treated with a para-phenylenediamine-containing oxidative hair dye.

In the organism of mammals, important detoxification pathways of arylamines are catalysed by N-acetyltransferase 2 (NAT2). A recent case-control epidemiology study suggested that human NAT2 slow acetylators exposed to oxidative hair dyes may be at greater risk to develop bladder cancer. We therefore profiled urinary [(14)C]-metabolites and NAT2 genotype in eight human subjects following treatment with a dark-shade oxidative hair dye containing [(14)C]-para-phenylenediamine (PPD). Genotyping identified three subjects as slow, and five subjects as intermediate NAT2 acetylators. Within 24 h after treatment, the study subjects excreted a mean total of 0.43+/-0.24% of the applied [(14)C] in the urine, where five different metabolites were found. The major urinary metabolites were concluded to be N-mono-acetylated and N,N'-diacetylated PPD. They were present in all urine samples and amounted to 80-95% of the total urinary [(14)C]. Another metabolite, possibly a glucuronic acid conjugate, was found in 6/8 urine samples at 5-13% of the total urinary [(14)C]. All metabolites appeared to be related to PPD, no evidence of the presence of high-molecular weight dye-intermediates or corresponding metabolites was found. The metabolite profile in the study subjects showed no significant differences between the NAT2 intermediate and NAT2 slow acetylator subgroups. Urine of NAT2 slow acetylators contained N-mono-acetylated-PPD at 42.2+/-10.2% and N,N'-di-acetylated-PPD at 54.1+/-7.6% of total urinary radioactivity, while the corresponding values of intermediate acetylators were 46.0+/-8.9% and 45.7+/-9.9%, respectively. Overall, our results suggest that the human acetylation rate of PPD after topical application is independent of the NAT2 genotype status, most likely due to metabolism by epidermal NAT1 prior to systemic absorption.     

Perfil lipídico em pacientes adultos com artrite idiopática juvenil

The inflammatory processes in the joints of a child with juvenile idiopathic arthritis (JIA) can persist into adulthood. Inflammation has been linked to distortions of the lipid profile and accelerated atherogenesis. In the present study, we examined the lipid profiles of adults with JIA compared with those of healthy people. A lipid profile of a sample of 54 adults with JIA (57.3% with polyarticular JIA, 37.0% with oligoarticular JIA, 1.9% with enthesitis-related JIA and 3.7% with systemic onset JIA) and 54 healthy subjects were compared. In the adults with JIA, data on gender, age, age at disease onset, the presence of rheumatoid factor (RF) and antinuclear antibodies (ANA), a Health Assessment Questionnaire (HAQ) and the disease duration were collected. We found that hypercholesterolaemia, increased low-density lipoprotein (LDL) and decreased high-density lipoprotein (HDL) were more common in patients with JIA than the controls (P = 0.016, P < 0.0001 and P = 0.0008, respectively). Changes in the levels of total cholesterol (TC) and LDL were more common in the individuals who had a later onset of disease (P = 0.0017 for TC and P = 0.023 for LDL). In the entire JIA group, no other variable, such as RF, ANA, disease duration or responses to the HAQ, could be linked to dyslipidaemia (P = non-significant). We concluded that the adult patients with JIA have a lipid profile with increased TC and LDL levels and decreased levels of HDL compared to the controls. No clinical feature could be correlated with this change except for the age at disease onset.     

Plasma somatostatin is elevated in primary hypothyroidism compared with hyperthyroidism

Increased pancreatic somatostatin (somatotrophin release inhibiting factor (SRIF) has been found in hypothyroid rats. Therefore, we wanted to investigate plasma SRIF in patients with hypo- and hyperthyroidism. Two groups of patients, 7 cases with autoimmune hypothyroidism, 31-75 years old, and 7 cases with Graves' disease, 19-43 years old, were compared with regard to plasma SRIF before, during and after an arginine infusion (0.5 g/kg/20 min). None of the patients suffered from diabetes mellitus or obesity. Plasma SRIF was higher in the hypothyroid patients (mean basal value 21.5 +/- 3.9, peak value 28.7 +/- 5.1 pmol/l) compared with the hyperthyroid group (mean basal value 11.6 +/- 3.3, peak value 16.2 +/- 4.0 pmol/l). The hypothyroid group also had significantly higher serum insulin values during arginine stimulation. No difference was found in plasma glucagon, serum growth hormone (GH) or blood glucose. In conclusion, plasma SRIF is elevated in primary hypothyroidism compared with hyperthyroidism. The reason for this finding is uncertain, but a reduced SRIF clearance is a possible explanation. The association of our findings with the reduced glucose tolerance in hyperthyroidism is discussed.     

Protection of Chinese painted quails (Coturnix chinensis) against a highly pathogenic H5N1 avian influenza virus strain after vaccination

Chinese painted quails immunized with a single dose (6 μg HA) of inactivated H5N1 (clade 1) influenza vaccine NIBRG-14 and challenged with 100 LD₅₀ of the heterologous A/Swan/Nagybaracska/01/06(H5N1) (clade 2.2) strain were protected, whereas unvaccinated quails died after challenge. No viral antigens or RNA were detected in cloacal swabs from immunized animals. Sera obtained post-immunization gave low titres in serological assays against the vaccine and the challenge viruses. Our results demonstrate the protective efficacy of the NIBRG-14 strain against the challenge virus and the usefulness of these small birds in protection studies of influenza vaccines.     

Anti-<Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> (ASCA) and anti-endomysial antibodies in spondyloarthritis

Spondyloarthritis (SpA) are diseases with increased gut inflammation. To search for (anti-Saccharomyces cerevisiae) ASCA IgA, ASCA IgG, and anti-endomysial antibodies (EmA-IgA) in a cohort of 70 patients with SpA, we found 18.6% (13/70) positive for IgA-ASCA in the SpA group and 3/57 (5.2%) in the control group (P = 0.031). ASCA IgG and EmA-IgA were found at the same frequency in SpA and controls. No relationship of ASCA IgA positivity could be established with disease activity (measured by ESR, C-reactive protein, and BASDAI), presence of uveitis, or peripheral arthritis neither with functional status measured by BASFI. SpA patients present an increase in the IgA-ASCA positivity without any relationship to disease activity, functional index, clinical profile or the presence of HLA-B27. There is no evidence of higher prevalence of EmA-IgA in SpA patients in the studied sample.