Biologic Activities of the TolC-Like Protein of Neisseria meningitidis as Assessed by Functional Complementation in Escherichia coli

Neisseria meningitidis can produce a TolC-like protein needed for secretion of FrpC but not efflux of antimicrobials. We now report that expression of the meningococcal tolC gene in a TolC-deficient strain of Escherichia coli can restore properties of α-hemolysis and antimicrobial resistance known to involve efflux pumps.Despite considerable progress in understanding the pathophysiology of invasive meningococcal disease and the contribution of bacterial virulence factors, much remains to be learned. In particular, little definitive information is available regarding virulence factors that Neisseria meningitidis secretes to the extracellular fluid during infection and how they might damage host cells and tissues or modulate inflammatory responses that are protective or damaging. Certain strains of N. meningitidis (8), but not of the related pathogen Neisseria gonorrhoeae, produce a type I secretion system similar to the HlyB-HlyD-TolC efflux pump of Escherichia coli (29), known to be important in the extracellular production of α-hemolysin (HlyA) (12, 27, 28). Klee et al. (8) described a DNA island in certain strains of N. meningitidis that contains tandemly linked hylD and tolC genes that we showed (7) are cotranscribed. Wooldridge et al. (29) demonstrated that N. meningitidis contains an unlinked hlyB gene and predicted the presence of a functional HlyB-HlyD-TolC efflux system in N. meningitidis. We (7) recently showed that meningococcal FrpC, which bears amino acid similarity to HlyA (23, 24), but has unknown biological activity (4), is secreted by the HlyB-HlyD-TolC efflux pump.Although N. meningitidis uses TolC in conjunction with HlyB-HlyD for FrpC export (7), as shown previously for its function with the AcrA-AcrB system in E. coli (5), it is not required for efflux of antimicrobials in the meningococcus. Rather, the MtrE proteins of N. meningitidis and N. gonorrhoeae work with the MtrC-MtrD efflux proteins as the outer membrane protein (OMP) channel for export of antimicrobials (3, 7, 17, 21). The AcrA-AcrB-TolC and MtrC-MtrD-MtrE efflux pumps are structurally and functionally similar (21). The amino acid similarity between the TolC OMPs possessed by E. coli and N. meningitidis, their similarity to MtrE (3), and the fact that N. meningitidis has two similar OMPs (MtrE and TolC) led us to further investigate the biologic activity of meningococcal TolC. Accordingly, we asked if this protein could functionally replace TolC used by E. coli in its secretion of HlyA and efflux of antimicrobials. Using a complementation strategy, we found that TolC produced by N. meningitidis can participate in both export functions when expressed in E. coli, suggesting that it has the intrinsic ability to interact with components of bacterial efflux pumps that are involved in antimicrobial resistance and toxin secretion.(A preliminary account of these findings was presented at the 16th International Pathogenic Neisseria Conference, held in Rotterdam, The Netherlands, from 7 to 12 September 2008.)     

Investigation of trace metals in the blood plasma and scalp hair of gastrointestinal cancer patients in comparison with controls

BackgroundGastrointestinal cancer is one of the most common types of cancer which is predominantly associated with the environmental factors. The carcinogenic processes are linked with the imbalances of trace metals in body fluid and tissues.MethodsTrace metals (Cd, Cr, Cu, Fe, Ni, Pb and Zn) are estimated in blood plasma and scalp hair of the cancer patients and controls employing nitric acid–perchloric acid based wet-digestion followed by atomic absorption spectrophotometric method.ResultsThe mean concentrations of Cd, Cr, Cu and Ni were found to be significantly higher in the plasma of patients compared with the controls, however, appreciably higher concentrations of Fe and Zn were observed in the plasma of controls. The average scalp hair concentrations of Zn, Fe, Pb, Cu and Cd were notably higher in the patients than controls. The correlation study revealed significantly different mutual variations of the trace metals in the plasma and scalp hair of the patients and controls. The apportionment of trace metals in the plasma and scalp hair of the patients and controls was also considerably different.ConclusionsThe study revealed that the carcinogenic processes are significantly affecting the trace metal burden and mutual variations in the cancerous patients compared with the controls.     

Long-term compliance with follow-up after treatment for cervical intra-epithelial neoplasia

Objective. To assess the level of compliance with follow-up over time after treatment for preinvasive and Stage Ia1 lesions of the cervix. To compare the average interval between visits with the interval prescribed by protocol and to evaluate the use of this difference as a measure of compliance. Design. Retrospective observational study. Setting. London university hospital. Population. Women who received treatment for preinvasive (CINI-III, AIS) or Stage Ia1 cervical lesions. Methods. Attendance data were obtained from hospital-based colposcopy and community-based databases. Main outcome measures. The average interval between the appointments attended by each woman was compared with the planned interval between visits. The time that elapsed since the previous appointment attended was calculated for each visit and correlated with the time since treatment. Results. 1013 women attended 4128 follow-up visits in the colposcopy clinic and in the community. Twenty-two (2.2%) women never attended any post-treatment appointment and 209 (21.0%) of the 991 women who attended at least once, did so on average more than 12 months later than specified by the follow-up protocol. There was a highly significant correlation between the interval since the previous appointment and the time since treatment (Kendall's tau b = 0.529614, two-sided p < 0.0001), showing that compliance deteriorates with increasing time since treatment. Conclusions. Comparing the average interval between attendances with the planned interval prescribed by protocol is a sensitive measure of compliance. Compliance with follow-up deteriorates significantly with time since treatment. This decline in compliance may contribute to the increased risk of invasive disease after treatment.     

Under‐reporting of sudden unexpected death in epilepsy

Aims. The identification and characterization of sudden unexpected deaths in epilepsy (SUDEP) may be improved, helping to optimize prevention and intervention. We set out to assess the frequency and demographic and clinical characteristics of SUDEP cases in a sudden death cohort. Methods. All out‐of‐hospital deaths were investigated from March 1, 2013 to February 28, 2015 in Wake County, NC, attended by the Emergency Medical Services. Cases were screened and adjudicated by three physicians to identify sudden death cases from any cause among free‐living adults, aged 18–64. In total, 399 sudden death victims were identified during this two‐year period. Seizure history, demographic and clinical characteristics, and healthcare utilization patterns were assessed from death records, emergency response scene reports, and medical records. Sudden death cases with a history of seizures were summarized by an experienced chart abstractor (SC) and adjudicated by an experienced neurologist (OD). We then compared demographic and clinical characteristics and healthcare utilization patterns of neurologist‐identified SUDEP cases to other sudden death victims in our population‐based registry of sudden death from any cause. Results. SUDEP accounted for 5.3% of sudden deaths. However, seizures or complications of seizures were only considered the primary cause of death on death certificates in 1.5% of sudden deaths. SUDEP cases were more likely to have a history of alcohol abuse. Mental health disorders and a low level of medication compliance and healthcare utilization were common among SUDEP victims. Conclusions. SUDEP accounts for approximately 5.3% of sudden deaths from any cause in individuals aged between 18 and 64. Death certificates underestimate the burden of sudden death in epilepsy, attributing only 1.5% of sudden deaths to seizures or complications of seizures. Accurate documentation of epileptic disorders on death certificates is essential for the surveillance of SUDEP. Further, interventions that promote better use of medical services and patient engagement with healthy living practices may reduce sudden deaths in epilepsy.     

<Emphasis Type="Italic">TOX3</Emphasis> Variants Are Involved in Restless Legs Syndrome and Parkinson’s Disease with Opposite Effects

Parkinson’s disease (PD) and restless legs syndrome (RLS) may be clinically and/or etiologically related, yet this association is under debate. Single-nucleotide polymorphisms (SNPs) in the TOX3 gene locus were implicated in both RLS and PD genome-wide association studies (GWASs), suggesting a potential pleiotropy. Two case-control cohorts including 644 PD patients, 457 RLS patients, and 945 controls were genotyped for one known RLS-related SNP (rs3104767) and one PD-related SNP (rs4784226) in the TOX3 locus. The associations between genotype and PD and RLS risk were tested using multivariate regression models. The allele frequencies of RLS-related SNP rs3104767 in RLS patients and controls were 0.35 and 0.43, respectively (OR 0.70, p?=?0.0007). Regression model suggested that this association is derived by homozygous carriage of rs3104767 (adjusted p?=?0.008). A nominal association was observed for homozygous carriers of the rs3104767 SNP in PD (OR 1.62, 95% CI 1.05–2.54, p?=?0.034), i.e., with an opposite direction of effect on RLS and PD, but this was not significant after Bonferroni correction. However, data from published GWASs of RLS and PD, and from the PDgene database, further supported these inverse associations. Our results confirm the association between the TOX3 SNP rs3104767 and RLS and suggest that TOX3 variants are involved in both RLS and PD, but with different or even opposite effects. Studies in larger populations of different ethnicities are required to further refine the TOX3 locus is involved in RLS and PD.     

Genetic aspects of severe childhood obesity

Genetic factors are involved in the regulation of body weight and in determining individual responses to environmental factors such as diet and exercise. The identification and characterization of monogenic obesity syndromes has led to an improved understanding of the precise nature of the inherited component of severe obesity and has had undoubted medical benefits, whilst helping to dispel the notion that obesity represents an individual defect in behaviour with no biological basis. For individuals at highest risk of the complications of severe obesity, such findings provide a starting point for providing more rational mechanism based therapies as has successfully been achieved for one disorder, congenital leptin deficiency.     

Use of radiologic imaging to enhance physical diagnosis instruction in the preclinical curriculum

RATIONALE AND OBJECTIVES: To expose students in the premedical years to imaging and its indications, to enhance their understanding of pathologic processes by allowing direct visualization, and to teach physical diagnosis through an integrated, multispecialty approach. MATERIALS AND METHODS: A total of 166 second-year medical students participated in a novel imaging session that accompanied the physical diagnosis course they were concurrently enrolled in. Students were provided a didactic orientation to imaging and taught how to use Picture Archiving and Communications System software. The students then participated in interactive imaging sessions in which they were able to scroll through entire imaging cases of real, anonymized patients with accompanying clinical scenarios and physical examination findings. RESULTS: Of 89 students responding to an online curricular feedback questionnaire, 41% believed that the imaging correlated with the other information taught in the course and 46% found it was helpful to their learning. The majority of students (64%) believed that the sessions helped challenge them to think about physical diagnosis in a different way. CONCLUSION: Physical diagnosis on the wards requires a multispecialty approach and the early introduction of this technique through the integrated mode of teaching we present will benefit students in their clinical years and future careers.     

Inflammatory myofibroblastic tumor of the lung in an adolescent boy

Inflammatory myofibroblastic tumors of the lung are rare, here, an unusual case is described. A 14-year-old boy presented with a history of weight loss and clubbing and was found to have a solitary circumscribed mass in right lower lobe treated with lobectomy. This case indicates the need for early and complete removal of the inflammatory myofibroblastic tumor of the lung.     

Hypohidrotic ectodermal dysplasia (HED)

Hypohidrotic Ectodermal Dysplasia (HED) is a hereditary congenital disorder of ectodermal origin. It is characterized by lack of sweat glands (hypohidrosis), nail dystrophy(onychodysplasia), alopecia (hypotrichosis), defective palms and soles (palmoplantar hyperkeratosis) and the oral presentations of partial absence of teeth (hypodontia) or complete absence of teeth (anodontia). Hypodontia of primary and permanent dentition is one of the most frequently occurring oral symptoms in HED patients. These features of poor aesthetic affect the social and the psychological well-being of the patient. This case report describes the prosthetic rehabilitation of a HED patient.