A case of eruptive milia

A 68-year-old woman presented with a 10-year history of multiple milia on her scalp. Spontaneous eruptive milia are uncommon and the term describes cases that are more extensive in number and distribution than would be expected in primary milia.

Anxiety in medical students: is preparation for full-time clinical attachments more dependent upon differences in maturity or on educational programmes for undergraduate and graduate entry students?

INTRODUCTION

The transition to full-time clinical studies holds anxieties for most medical students. While graduate entry medical education has only recently begun in the UK, the parallel undergraduate and graduate entry MBBS courses taught at our school allowed us to study how 2 differently prepared groups perceived this vital time at a comparable stage in their training.

METHOD

An anonymous questionnaire collected demographic data and graded anxiety in 13 statements relating to starting full-time clinical attachments. Two open questions allowed free text comment on the most positive and negative influences perceived during this time. Both a statistical analysis and a qualitative assessment were performed to compare the 2 groups of students.

RESULTS

The 2 groups were similar with respect to gender but the graduate entry students were significantly older. The graduate entry students were significantly less anxious about most aspects of the transition period compared to the undergraduates. These course differences remained after adjusting for age and sex. When adjusted for course and age, male students expressed less anxiety. The main positive qualitative statements related to continual clinical and communication skills training in the graduate entry group. The main qualitative concerns in both groups related to 'fitting in' and perceived lack of factual knowledge.

DISCUSSION

These data support the early introduction of clinical skills teaching, backed up by a fully integrated clinically relevant curriculum with continued assessment, in preparing students and reducing levels of anxiety before they start full-time clinical attachments. These course design differences appear to be more important than any differences in maturity between the 2 groups.

Biological monitoring of kidney function among workers occupationally exposed to trichloroethylene

AIMS

To investigate the nephrotoxic potential of trichloroethylene in a currently exposed population using sensitive urinary markers of kidney toxicity.

METHODS

Renal dysfunction was monitored in a cross-sectional study of 70 workers currently exposed to trichloroethylene. An age and sex matched control population of 54 individuals was drawn from hospital and administrative staff.

RESULTS

The mean exposure to trichloroethylene, estimated from urinary trichloroacetic acid concentrations, was 32 ppm (range 0.5-252 ppm) with an average duration of exposure of 4.1 years (range 1-20 years). Significant differences between the exposed and control populations were found for nephrotoxicity markers N-acetylglucosaminidase (NAG) and albumin, and for the mode of action marker, formic acid. However, neither NAG nor albumin showed a significant correlation with either the magnitude or duration of exposure to trichloroethylene. There was a significant correlation between urinary formic acid and trichloroacetic acid concentrations. Within the exposed population there were dose dependent increases in urinary methylmalonic acid concentrations and urinary glutathione S-transferase alpha activity. Although still within the control range, these changes were clearly dose dependent and consistent with one of the proposed mechanisms of trichloroethylene induced kidney toxicity.

CONCLUSION

Although there was no evidence of kidney toxicity within the population studied, the results suggest that kidney damage could occur at exposure concentrations higher (>250 ppm) than those encountered in this study.

Effect of experimenter-delivered and self-administered cocaine on extracellular beta-endorphin levels in the nucleus accumbens

Beta-endorphin is an endogenous opioid peptide that has been hypothesized to be involved in the behavioral effects of drugs of abuse including psychostimulants. Using microdialysis, we studied the effect of cocaine on extracellular levels of beta-endorphin in the nucleus accumbens, a brain region involved in the reinforcing effects of psychostimulant drugs. Experimenter-delivered cocaine (2 mg/kg, i.v.) increased extracellular beta-endorphin immunoreactive levels in the nucleus accumbens, an effect attenuated by 6-hydroxy-dopamine lesions or systemic administration of the D1-like receptor antagonist, SCH-23390 (0.25 mg/kg, i.p.). The effect of cocaine on beta-endorphin release in the nucleus accumbens was mimicked by a local perfusion of dopamine (5 microm) and was blocked by coadministration of SCH-23390 (10 microm). Self-administered cocaine (1 mg/kg/infusion, i.v.) also increased extracellular beta-endorphin levels in the nucleus accumbens. In addition, using functional magnetic resonance imaging, we found that cocaine (1 mg/kg, i.v.) increases regional brain activity in the nucleus accumbens and arcuate nucleus. We demonstrate an increase in beta-endorphin release in the nucleus accumbens following experimenter-delivered and self-administered cocaine mediated by the local dopaminergic system. These findings suggest that activation of the beta-endorphin neurons within the arcuate nucleus-nucleus accumbens pathway may be important in the neurobiological mechanisms underlying the behavioral effects of cocaine.

H-Type 1 carbohydrate antigen expression by ovine endometrial cells

Our objective was to determine whether H-Type 1 carbohydrate antigen is expressed by ovine endometrial epithelial cells. Endometrium was obtained from sheep on days (D) 1, 5, 11, 13, and 15 of the estrous cycle or pregnancy and D17 and D19 of pregnancy. Immunofluorescence microscopy of frozen tissue sections revealed intense staining on the apical surface of glandular uterine epithelial (GE) cells from D11 to D17 of pregnancy. Light punctate staining of luminal uterine epithelial (LE) cells was present from D15 to D19 of pregnancy, with isolated areas of intense staining observed only on D15 of pregnancy. There were no noticeable differences in staining patterns on equivalent d of the estrous cycle. Immortalized sheep LE and GE cells were used to determine whether estradiol (E), progesterone (P), or E + P, with or without interferon tau (IFNtau), regulates H-Type 1 antigen expression in vitro. Intermittent punctate surface staining was observed on both cell lines independent of steroid treatment. Treatment with P or IFNtau increased H-Type 1 antigen expression (P < 0.01) and resulted in large aggregates of punctate staining. Domain-specific biotinylation and Western blotting of cell lysates from LE and GE cells were used to identify proteins carrying the H-Type 1 antigen. For both cell types, major immunoreactive apical membrane proteins were detected at 31, 33, 42, 55, 60, and 70 kDa. Therefore, the H-type 1 antigen is expressed mainly on GE cells during pregnancy recognition in utero and up-regulated by P and IFNtau on LE and GE cells in vitro.

The role of cytochromes P-450 in styrene induced pulmonary toxicity and carcinogenicity

Exposure of CD-1 mice to atmospheres of 40 and 160 ppm styrene, daily for up to 10 days, caused pulmonary toxicity characterised by focal loss of cytoplasm and focal crowding of non-ciliated Clara cells, particularly in the terminal bronchiolar region. The toxicity was accompanied by an increase in cell replication rates in terminal and large bronchioles of mice exposed for 3 days or longer. The toxicity and increased cell replication were no longer apparent after a 2-day break in exposure, but re-occurred when exposure was resumed. Similar effects were seen in mice given oral doses of 10, 100 or 200 mg/kg styrene, daily for 5 days. Increases in cell replication rates were seen in the terminal bronchioles in mice dosed with 100 and 200 mg/kg styrene, but not 10 mg/kg. Toxicity was limited to 3 to 10 animals in the 200 mg/kg group. Neither morphological nor cell proliferation effects were seen in the alveolar region of the mouse lung in any of these studies, nor were any effects observed in the lungs of CD rats exposed to 500 ppm styrene for up to 10 days. The pulmonary toxicity and increased cell division seen in mice, but not rats, correlates with the known species differences in pulmonary carcinogenicity of styrene, suggesting that the acute and chronic responses are causally related. 5-Phenyl-1-pentyne was shown to inhibit the pulmonary cytochrome P-450 metabolism of styrene in vivo. Cell replication rates in the lungs of mice treated with this inhibitor and exposed to styrene were comparable with controls demonstrating that the pulmonary effects of styrene on the mouse lung are caused by a metabolite of styrene, probably styrene oxide. The risks associated with exposure to styrene appear to correlate well with the metabolic capacity of the lung.

Genetic variation in the 5q31 cytokine gene cluster confers susceptibility to Crohn disease

Linkage disequilibrium (LD) mapping provides a powerful method for fine-structure localization of rare disease genes, but has not yet been widely applied to common disease. We sought to design a systematic approach for LD mapping and apply it to the localization of a gene (IBD5) conferring susceptibility to Crohn disease. The key issues are: (i) to detect a significant LD signal (ii) to rigorously bound the critical region and (iii) to identify the causal genetic variant within this region. We previously mapped the IBD5 locus to a large region spanning 18 cM of chromosome 5q31 (P<10(-4)). Using dense genetic maps of microsatellite markers and single-nucleotide polymorphisms (SNPs) across the entire region, we found strong evidence of LD. We bound the region to a common haplotype spanning 250 kb that shows strong association with the disease (P< 2 x 10(-7)) and contains the cytokine gene cluster. This finding provides overwhelming evidence that a specific common haplotype of the cytokine region in 5q31 confers susceptibility to Crohn disease. However, genetic evidence alone is not sufficient to identify the causal mutation within this region, as strong LD across the region results in multiple SNPs having equivalent genetic evidence-each consistent with the expected properties of the IBD5 locus. These results have important implications for Crohn disease in particular and LD mapping in general.

The toxicity of styrene to the nasal epithelium of mice and rats: studies on the mode of action and relevance to humans

Inhaled styrene is known to be toxic to the nasal olfactory epithelium of both mice and rats, although mice are markedly more sensitive. In this study, the nasal tissues of mice exposed to 40 and 160 ppm styrene 6 h/day for 3 days had a number of degenerative changes including atrophy of the olfactory mucosa and loss of normal cellular organisation. Pretreatment of mice with 5-phenyl-1-pentyne, an inhibitor of both CYP2F2 and CYP2E1 completely prevented the development of a nasal lesion on exposure to styrene establishing that a metabolite of styrene, probably styrene oxide, is responsible for the observed nasal toxicity. Comparisons of the cytochrome P-450 mediated metabolism of styrene to its oxide, and subsequent metabolism of the oxide by epoxide hydrolases and glutathione S-transferases in nasal tissues in vitro, have provided an explanation for the increased sensitivity of the mouse to styrene. Whereas cytochrome P-450 metabolism of styrene is similar in rats and mice, the rat is able to metabolise styrene oxide at higher rates than the mouse thus rapidly detoxifying this electrophilic metabolite. Metabolism of styrene to its oxide could not be detected in human nasal tissues in vitro, but the same tissues did have epoxide hydrolase and glutathione S-transferase activities, and were able to metabolise styrene oxide efficiently, indicating that styrene is unlikely to be toxic to the human nasal epithelium.

Structural and oxo-transfer reactivity differences of hexacoordinate and pentacoordinate (nitro)(tetraphenylporphinato)cobalt(III) derivatives

The oxo-transfer catalyst (nitro)(pyridyl)cobalt(III) tetraphenylporphyrin has been reinvestigated by substitution of the distal pyridine ligand with 4-N,N-dimethylaminopyridine and 3,5-dichloropyridine. Differences in their structures and in the reactivity of the compounds toward catalytic secondary oxo transfer were investigated by FT-IR and UV-visible spectroscopy, cyclic voltammetry, X-ray diffraction, semiempirical calculations, and reactions with alkenes in dichloromethane solution. Very modest differences in the hexacoordinate compounds' structures were predicted and observed, but the secondary oxo-transfer reactivity at the nitro ligand varies markedly with the basicity of the pyridine ligand and the position of the coordination equilibrium. Oxo transfer occurs rapidly through the pentacoordinate species (nitro)cobalt(III) tetraphenylporphyrin that is generated by dissociation of the pyridine ligand and therefore is strongly related to the Hammett parameters of these nitrogenous bases. The reactive pentacoordinate species CoTPP(NO(2)) can be generated in solution by addition of lithium perchlorate to (py)CoTPP(NO(2)) by Lewis acid-base interactions or more simply by using the weaker Lewis base Cl(2)py instead of py as the distal ligand. In contrast to pentacoordinate (nitro)iron porphyrins, disproportionation reactions of CoTPP(NO(2)) compound are not evident. This pentacoordinate derivative, CoTPP(NO(2)), is reactive enough to stoichiometrically oxidize allyl bromide in minutes. Preliminary catalytic oxidation reaction studies of alkenes also indicate the involvement of both radical and nonradical oxo-transfer steps in the mechanism, suggesting formation of a peroxynitro intermediate in the reaction of the reduced CoTPP(NO) with O(2).

The influence of co-exposure to dimethyldithiocarbamate on butadiene metabolism

Treatment of rats and mice with a single oral dose of dimethyldithiocarbamate (DMDTC; 250 mg/kg) had a marked effect on hepatic CYP2E1 and aldehyde dehydrogenase activities, measured in vitro, for up to 24 h after dosing. The same treatment did not affect CYP2A6, glutathione S-transferase, epoxide hydrolase, alcohol dehydrogenase activities or hepatic glutathione levels. As a consequence of the loss of CYP2E1 activity, butadiene metabolism in liver fractions from DMDTC treated rats and mice was markedly reduced, as was the metabolism of the mono-epoxide to the di-epoxide in mouse liver. The conversion of the mono-epoxide to the diol by epoxide hydrolases was not affected by DMDTC treatment. Urinary excretion of radioactivity, following dosing with DMDTC and exposure to 200 ppm C-14 butadiene for 6 h, was markedly reduced in rats, but increased in mice. The profiles of urinary metabolites were qualitatively similar from mice exposed to butadiene to those exposed after dosing with DMDTC. In the rat, pre-dosing with DMDTC resulted in the formation of three additional urinary metabolites following exposure to butadiene. Overall, DMDTC appears to impact qualitatively and quantitatively on the metabolism of butadiene. The nature and full significance of these changes has yet to be characterised.

The control of syphilis, a contemporary problem: a historical perspective

The control of syphilis in the United Kingdom and United States has been managed in different ways in each country over the course of the last century. Older more established measures including contact tracing, serological surveillance, and health education strategies together with effective antibiotic therapy have had some success. However, changing social structures on both sides of the Atlantic Ocean have brought newer mathematical and epidemiological methods to the fore. This review looks at the past management of syphilis control in the United Kingdom and United States, and speculates on future prospects for disease management in these countries.

A susceptibility locus for asthma-related traits on chromosome 7 revealed by genome-wide scan in a founder population

The genetics of asthma and atopy have been difficult to determine because these diseases are genetically heterogeneous and modified by environment. The pedigrees in our study (n=86) originate in eastern central Finland (Kainuu province). According to census records, this region had only 200 households (2,000 inhabitants) in the mid sixteenth to mid seventeenth centuries. The current population of 100,000 represents the expansion of these founders within the past 400 years. Because this population is relatively homogeneous, we hypothesized that the molecular genetic mechanisms underlying asthma might also have reduced heterogeneity and therefore be easier to dissect than in mixed populations. A recent twin family study supported a strong genetic component for asthma in Finland. We carried out a genome-wide scan for susceptibility loci in asthma in the Kainuu subpopulation. We identified two regions of suggestive linkage and studied them further with higher-density mapping. We obtained evidence for linkage in a 20-cM region of chromosome 7p14-p15 for three phenotypes: asthma, a high level of immunoglobulin E (IgE; atopy) and the combination of the phenotypes. The strongest linkage was seen for high serum IgE (non-parametric linkage (NPL) score 3.9, P=0.0001), exceeding the threshold for genome-wide significance based on simulations. We also observed linkage between this locus and asthma or atopy in two independent data sets.

A randomized controlled trial of a passive accessory joint mobilization on acute ankle inversion sprains

BACKGROUND AND PURPOSE

Passive joint mobilization is commonly used by physical therapists as an intervention for acute ankle inversion sprains. A randomized controlled trial with blinded assessors was conducted to investigate the effect of a specific joint mobilization, the anteroposterior glide on the talus, on increasing pain-free dorsiflexion and 3 gait variables: stride speed (gait speed), step length, and single support time.

SUBJECTS

Forty-one subjects with acute ankle inversion sprains (<72 hours) and no other injury to the lower limb entered the trial.

METHODS

Subjects were randomly assigned to 1 of 2 treatment groups. The control group received a protocol of rest, ice, compression, and elevation (RICE). The experimental group received the anteroposterior mobilization, using a force that avoided incurring any increase in pain, in addition to the RICE protocol. Subjects in both groups were treated every second day for a maximum of 2 weeks or until the discharge criteria were met, and all subjects were given a home program of continued RICE application. Outcomes were measured before and after each treatment.

RESULTS

The results showed that the experimental group required fewer treatment sessions than the control group to achieve full pain-free dorsiflexion. The experimental group had greater improvement in range of movement before and after each of the first 3 treatment sessions. The experimental group also had greater increases in stride speed during the first and third treatment sessions. DISCUSSION AND CONCLUSION Addition of a talocrural mobilization to the RICE protocol in the management of ankle inversion injuries necessitated fewer treatments to achieve pain-free dorsiflexion and to improve stride speed more than RICE alone. Improvement in step length symmetry and single support time was similar in both groups.

Methyl methacrylate toxicity in rat nasal epithelium: studies of the mechanism of action and comparisons between species

Female F344 rats exposed to 200 ppm methyl methacrylate for 6 h developed a lesion in the nasal olfactory epithelium which was characterised by degeneration and atrophy. The severity of the lesion was markedly reduced by pre-treatment of the rats with an intraperitoneal dose of 100 mg/kg bis-(p-nitrophenyl)phosphate, an inhibitor of carboxylesterase enzymes, thus demonstrating that the lesion is caused by the carboxylesterase mediated metabolism of methyl methacrylate to methacrylic acid, an irritant and corrosive metabolite. The distribution of the carboxylesterases in nasal tissues has been investigated and the metabolism of methyl methacrylate to methacrylic acid has been compared in rat, hamster and human nasal tissue fractions in vitro. Histocytochemistry showed that the carboxylesterases are heavily localised in the sustentacular cells and Bowman's glands of the rat olfactory region, but are more generally distributed in human olfactory epithelium. Consistent with this, the enzyme activity in all three species was higher in fractions prepared from olfactory tissue than from respiratory tissue, 3-fold in rat and human and 12-fold in the hamster. The maximum rates (V(max)) of metabolism in rat and hamster olfactory tissue fractions were comparable, whereas those in human olfactory tissue fractions were at least 13-fold lower. The rate of metabolism in rat olfactory tissue was also comparable to that in rat liver whereas in humans, the rate in olfactory tissue was 500-fold lower than that in the liver. In respiratory tissues, the rate in humans was at least 6-fold lower than that in the rat. These results suggest that humans are significantly less sensitive than rodents to the nasal toxicity of methyl methacrylate.