A pilot study to identify factors associated with frailty within the World Trade Center general responder cohort

BACKGROUND

Given the significant exposures experienced by the World Trade Center (WTC) general responders, there is increasing interest in understanding the effect of these exposures on aging in this population. We aim to identify factors that may be associated with frailty, a clinical syndrome characterized by a decrease in one's reserve that has been linked to poor health outcomes.

METHODS

WTC general responders enrolled in the WTC Health Program aged 50 and older provided informed consent. Validated frailty assessments, the Frailty Phenotype (with the Johns Hopkins Frailty Assessment Calculator) along with the FRAIL scale, categorized nonfrail from prefrail/frail. Fall risk, functional status, and cognition were also assessed. WTC variables, including an identified WTC-certified condition, were utilized. The risk of frailty was estimated using log binomial regression analysis. A 95% confidence interval (CI) was used to estimate the prevalence ratio (PR).

RESULTS

One hundred and six participants were included; 38 (35.8%) were classified as pre-frail or frail. More of the pre-frail/frail group were obese (57.9% vs. 25%; p = 0.004) and had a WTC-certified condition (78.9% vs. 58.8%; p = 0.036). Obesity (PR = 2.43, 95% CI = 1.31, 4.53), a WTC-certified condition (PR = 1.77, 95% CI = 1.09, 2.89), and risk of falling (PR = 1.97, 95% CI = 1.01, 3.84) were independently associated with frailty.

CONCLUSIONS

Obesity and having a WTC-certified condition were found to be risk factors for frailty in our pilot study. Future work may focus on further identifying risk factors for frailty in the larger WTC general responder population.

Erratum: Rotavirus Genotypes and Vaccine Effectiveness from a Sentinel, Hospital-Based, Surveillance Study for Three Consecutive Rotavirus Seasons in Lebanon

[This corrects the article DOI: 10.1371/journal.pone.0161345.].

POLYPHARMACY AND FRAILTY AMONG WORLD TRADE CENTER GENERAL RESPONDERS

Polypharmacy in older adults is associated with increased risk of adverse events such as falls, adverse drug reactions and functional decline. WTC responders suffer from conditions related to WTC exposure and are at higher risk of polypharmacy. We examined patterns of medication use among WTC general responders aged 50 and over who had at least one visit from 2017 to 2019 (n=7,679); 56.1% took 5+ medications and 22.5% took 10+ medications. Factors associated with polypharmacy (taking 5+ medications) include age (OR 1.08, p<0.001), female sex (OR 1.33, p<0.001), obesity (1.90, p<0.001), fair/poor self-rated health (OR 1.32, p<0.001) and limitations on performing moderate activity (OR 1.52, p<0.001). Frailty, as measured by the deficit count in the Clinical Frailty Index, is associated with polypharmacy after adjusting for other covariates (OR 1.23, p<0.001). Addressing polypharmacy by improving medication use may yield health benefits for this rapidly aging population at risk for adverse outcomes.

Cardiovascular disease in the World Trade Center Health Program General Responder Cohort

BACKGROUND

Over 90,000 rescue and recovery responders to the September 2001 World Trade Center (WTC) attacks were exposed to toxic materials that can impair cardiac function and increase cardiovascular disease (CVD) risk. We examined WTC-related exposures association with annual and cumulative CVD incidence and risk over 17 years in the WTC Health Program (HP) General Responder Cohort (GRC).

METHODS

Post 9/11 first occurrence of CVD was assessed in 37,725 responders from self-reported physician diagnosis of, or current treatment for, coronary artery disease, myocardial infarction, stroke and/or congestive heart failure from WTCHP GRC monitoring visits. Kaplan-Meier estimates of CVD incidence used the generalized Wilcoxon test statistic to account for censored data. Cox proportional hazards regression analyses estimated the CVD hazard ratio associated with 9/11/2001 arrival in responders with and without dust cloud exposure, compared with arrival on or after 9/12/2001. Additional analyses adjusted for comorbidities.

RESULTS

To date, 6.3% reported new CVD. In covariate-adjusted analyses, men's CVD 9/11/2001 arrival risks were 1.40 (95% confidence interval [CI] = 1.26, 1.56) and 1.43 (95% CI = 1.29, 1.58) and women's were 2.16 (95% CI = 1.49, 3.11) and 1.59 (95% CI = 1.11, 2.27) with and without dust cloud exposure, respectively. Protective service employment on 9/11 had higher CVD risk.

CONCLUSIONS

WTCHP GRC members with 9/11/2001 exposures had substantially higher CVD risk than those initiating work afterward, consistent with observations among WTC-exposed New York City firefighters. Women's risk was greater than that of men's. GRC-elevated CVD risk may also be occurring at a younger age than in the general population.

Genetic Diversity of Human Rotavirus A Among Hospitalized Children Under-5 Years in Lebanon

Human rotavirus remains a major cause of gastroenteritis worldwide despite the availability of effective vaccines. In this study, we investigated the genetic diversity of rotaviruses circulating in Lebanon. We genetically characterized the VP4 and VP7 genes encoding the outer capsid proteins of 132 rotavirus-associated gastroenteritis specimens, previously identified in hospitalized children (<5 years) from 2011 to 2013 in Lebanon. These included 43 vaccine-breakthrough specimens and the remainder were from non-vaccinated subjects. Phylogenetic analysis of VP4 and VP7 genes revealed distinct clustering compared to the vaccine strains, and several substitutions were identified in the antigenic epitopes of Lebanese specimens. No unique changes were identified in the breakthrough specimens compared to non-breakthroughs that could explain the occurrence of infection in vaccinated children. Further, we report the emergence of a rare P[8] OP354-like strain with a G9 VP7 in Lebanon, possessing high genetic variability in their VP4 compared to vaccine strains. Therefore, human rotavirus strains circulating in Lebanon and globally have accumulated numerous substitutions in their antigenic sites compared to those currently used in the licensed vaccines. The successful spread and continued genetic drift of these strains over time might undermine the effectiveness of the vaccines. The effect of such changes in the antigenic sites on vaccine efficacy remains to be assessed.

P900 The Heart Model: Automated LVEF calculation in the real world

Background

Heart Model (HM) is a proprietary, model-based algorithm for measurement of left ventricular ejection fraction (LVEF) in a 3D dataset acquired from an apical 4-chamber view by transthoracic echocardiography (TTE). There is evidence for superior reproducibility compared to 2D echo methods for LVEF measurement.

Objective

To assess the correlation of LVEF by HM with conventional, 2D LVEF methods.

Methods

All TTEs performed between 04-08/02/2019 by 2 HM-trained sonographers were included. Demographic characteristics, indication for TTE, LVEF by Simpson"s (LVEF_S), by "eyeballing" (LVEF_EB) and by HM (LVEF_HM), were recorded; LVEF for each study was also estimated by eye-balling by an experienced observer unaware of the reported LVEF (LVEF_IND). We compared LVEF by each method, their reciprocal correlations and their correlation with LVEF_HM. Image quality was rated excellent (endocardial border visible for all segments in the 3 apical views), good (&lt; 1 segment was not visible / view), adequate (&lt; 3 segments were not visible) and limited (&lt;4 segments were not visible). Indications for TTE were: assessment of LVEF in 1/3 of the studies, murmurs in 1/5, and other indications in the rest.

Results

We included 74 patients (42 M, mean age (SD) 69.8(13.9), range 18-92 years). Forty-nine (66%) patients were in sinus rhythm, 23 (31%) were in AF, and the rest were in various paced rhythms. Fifty patients (68%) had excellent, good or adequate images. The EFs calculated by different methods are shown in the Table (p &gt; 0.05 for all), an the Bland Altman plot (LVEF_EB vs HM) in the figure. LVEF_HM correlated modestly with the other methods if all studies were included (r = 0.535 LVEF_HM vs. LVEF_EB); the correlation improved if only good-quality studies were included (r = 0.769, p &lt; 0.001 for both). All combinations of LVEF_IND, LVEF_EB and LVEF_S had correlation coefficients &gt;0.93.

Conclusions

The Heart Model algorithm for LVEF measurement correlates well with traditional 2D methods in patients with good endocardial border definition, where its use can potentially improve reproducibility and reduce exam duration.

LVEF by method (good-quality studies) N = 50 Simpson"s Eyeballing HeartModel Independent Mean(%) 48.6 48.9 50.9 48.8 SD(%) 17.8 16.6 14.9 15.7 Median(%) 54.5 52.5 53 50 Range(%) 16-74 17.5-72.5 19-88 15-75 SD - standard deviation Independent - LVEF estimate (eyeballing) by independent observer unaware of reported EFs. LVEF_EB was chosen as it was available inall the reports.

Abstract P900 Figure. Bland Altman Plot (LVEF_EB vs LVEF_HM)

Prevalence and awareness of varicocele among athletes in Riyadh, Saudi Arabia

Purpose

To evaluate the prevalence and awareness about symptoms, and complications of varicocele among athletes (bodybuilding and aerobics exercises) in Riyadh, Saudi Arabia.

Patients and methods

A cross-sectional study of male athletes aged between 18 and 48 years old was carried out in multiple branches of fitness centers over a period of 13 months in Riyadh, Saudi Arabia. A total of 382 face-to-face interviews using a predesigned questionnaire were conducted to identify the levels of knowledge, attitude, and practice. A randomly selected 48 subjects were examined. Varicocele was diagnosed and graded based on clinical examination and Doppler ultrasonography.

Results

Of the participants, 157 (41%) lacked knowledge and awareness regarding varicocele, its symptoms and complications. Of the examined participants, 22 (46%) were found to have varicocele. No difference in varicocele was found among bodybuilders and aerobic athletes (P=0.249). Similarly, no difference was related to duration of exercise session whether for 1 hour or more (P=0.131). However, our study revealed a higher rate of varicocele among athletes who exercised more than three times per week (P=0.009). Testicular volume was neither significantly different among respondents with and without varicocele nor between the left or right sides within each group.

Conclusion

Knowledge about varicocele, its symptoms and complications is poor among male athletes in Riyadh, Saudi Arabia. Varicocele is more common in athletic men who are frequently exercising. Efforts to increase knowledge and enhance awareness of varicocele in young males, in general, are strongly warranted.

Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels

Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (d_f) of the fibrin network, the gel network formation time (T_GP) and the shear elastic modulus, respectively. The results of this first haemorheological application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure of forming clots to increasing levels of shear stress produces a corresponding elevation in d_f, consistent with the formation of tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded. The scaling relationship established between shear elasticity and d_f for fibrin clots and whole blood confirms the fibrin network as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase d_f and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for the study of the effects of physiological and pathological levels of shear on clot properties.

Rotavirus Genotypes and Vaccine Effectiveness from a Sentinel, Hospital-Based, Surveillance Study for Three Consecutive Rotavirus Seasons in Lebanon

Introduction

Globally, rotavirus (RV) is the leading cause of gastroenteritis (GE) in children. Longitudinal data about changes in RV genotype distribution and vaccine effectiveness (VE) are scarce. This study was conducted in Lebanon over 3 consecutive RV seasons to estimate the rate of RVGE hospitalization, identify RV genotypes, determine the seasonal and geographical variations, and calculate RV VE.

Materials and Methods

This prospective, multicenter, hospital-based surveillance study was conducted between 2011 and 2013 and enrolled children (<5 years) admitted for GE. Socio-demographic and clinical data about the current episode of GE at admission were collected. Genotypes were determined from stool samples testing positive for RV by PCR.

Results

Of 1,414 cases included in the final analysis, 83% were <2 years old and 55.6% were boys. Median duration of hospitalization was 4 days and 91.6% of GE cases were severe (Vesikari score ≥11). PCR testing showed that 30.3% of subjects were RV-positive of which 62.1% had fever versus 71.1% of RV-negative subjects (P = 0.001). RV was predominantly detected in the cold season from November till March (69.9%). G and P genotype pairs for all RV-positive stool specimens showed a predominance of G1P[8] in 36% (n = 154) of specimens, G9P[8] in 26.4% (n = 113), and G2P[4] in 17.8% (n = 76). RV-negative subjects were more likely to be RV-vaccinated (21%) compared to the RV-positive subjects (11.3%) (P<0.001), with a vaccine breakthrough rate of 18.8%. The ratio of RV1-vaccinated for each RV5-vaccinated subject was 7.8 and VE against RV disease was 68.4% (95%CI, 49.6%-80.2%).

Conclusion

RV is a major cause of GE requiring hospitalization of children under 5 years of age in Lebanon. A few genotypes predominated over the three RV seasons studied. Mass RV vaccination will likely decrease the burden of hospitalization due to RV. VE is similar to what has been observed for other middle-income countries.

Effect of rifampicin and gentamicin on Shiga toxin 2 expression level and the SOS response in Escherichia coli O104:H4

BACKGROUND

A novel pathotype, Shiga toxin-producing Escherichia coli O104:H4, was the cause of a severe outbreak that affected European countries, mainly Germany, in 2011. The effect of different regimens of rifampicin and gentamicin were evaluated to determine possible treatment modes for the novel strain, and to evaluate the SOS response and its effect on toxin release.

MATERIALS AND METHODS

Pulsed-field gel electrophoresis (PFGE) was performed on the novel E. coli O104:H4 pathotype and two pre-outbreak E. coli O104:H4 CDC strains. Transcript levels of the stx2 and recA gene (SOS response inducer) were evaluated using quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) in the novel E. coli O104:H4 samples subjected to different regimens of rifampicin and gentamicin. Consequently, reverse passive latex agglutination (RPLA) was used to determine the Stx2 titers in these samples. Western blot was performed to determine the LexA levels (SOS response repressor) in E. coli O104:H4. The efficacy of treatment with antimicrobial agents was assessed in BALB/c mice.

RESULTS

The outbreak and pre-outbreak strains are closely related as shown by PFGE, which demonstrated slight genomic differences between the three strains. The transcription level of the stx2 gene in the new pathotype was 1.41- and 1.75-fold that of the 2009 EL-2050 and 2009 EL-2071 pre-outbreak strains, respectively. Moreover, the transcription level of the stx2 gene in the new pathotype was substantially decreased as a result of treatment with the different concentrations of the antimicrobial agents, but was enhanced when the antibiotics were administered at two subinhibitory levels. RPLA data were in accordance with the qRT-PCR results. E. coli O104:H4 exposed to gentamicin at both sub-minimum inhibitory concentration (MIC) levels led to high transcription levels of the recA gene and lack of expression of the LexA protein, implying that the SOS response was activated. Rifampicin at both sub-MIC levels resulted in low transcript levels of the recA gene, indicating that the SOS response was not induced. In vivo, the highest survival rate in BALB/c mice was observed in the group that was treated with the minimum bactericidal concentration (MBC) of gentamicin.

CONCLUSION

The use of antimicrobial agents in E. coli O104:H4 infection seems to be effective at the MIC and MBC levels. This provides a promising ground for treatment of E. coli O104:H4.

Design of pairs of reflectors

Given a 3D reflecting surface G, which is not necessarily rotationally symmetric, away from a point source, and a direction e, we design a reflecting surface F so that the system (G,F) reflects all rays into the direction e. We also solve the near-field problem when the direction e is replaced by a given point R. The surface F satisfies a system of first-order partial differential equations that can be explicitly solved in terms of G and e. We also apply the same ideas to designing refracting plates, of which the Schmidt corrector plate is an example.

The inhibitory effect of micafungin on biofilm formation by Pseudomonas aeruginosa

This study assesses the potential effect of micafungin, an antifungal agent known to inhibit 1,3-β-D-glucan synthesis in Candida albicans, on biofilm formation of selected Pseudomonas aeruginosa isolates by decreasing the synthesis of extracellular matrix β-D-glucan forming units. The effect of an optimal therapeutic dose of 10 mg ml(-1) micafungin on the production of biofilm was monitored in vitro using a microtiter plate assay. Phenotypic reduction in the formation of biofilm was significant (based on average optical density; p < 0.05) in most of the isolates. Moreover, the relative gene expression of biofilm encoding genes for alginate and pellicles (algC and pelC, respectively), and the cell wall 1,3-β-D-glucan encoding gene (ndvB) was evaluated using quantitative reverse transcription PCR. For all the genes tested, the levels of mRNA transcription were also decreased significantly (p < 0.05) in micafungin-treated samples cf. their untreated counterparts. In conclusion, this study presents micafungin as a potential agent for disrupting the structure of a biofilm of P. aeruginosa allowing the possible exposure and treatment of core-planktonic cells.

First detection and sequence analysis of thebla-CTX-M-15 gene in Lebanese isolates of extended-spectrum-β-lactamase-producingShigella sonnei

The emergence in Shigella species of extended-spectrum beta-lactamases (ESBL) that impart resistance to third-generation cephalosporins is a growing concern world-wide. So far, however, ESBL-producing Shigella have only been reported seven times, albeit from seven different countries. In Lebanon, three ESBL-producing clinical isolates of S. sonnei were recovered from 30 cases of shigellosis diagnosed between July 2004 and October 2005. All three were found to be resistant to amoxycillin, cefotaxime, ceftazidime, aztreonam, trimethoprim/sulphamethoxazole, gentamicin, and kanamycin. Each harboured the bla-CTX-M gene, and the results of sequence analysis indicated this to be of the bla-CTX-M-15 type and encoded on a 70-kb plasmid, flanked by an insertion element (ISEcp1). The bla-TEM-1 gene was also detected on the chromosomes of two of the ESBL-producing isolates. Class-2 integrons containing dhfr1, aadA1 and sat1 genes were detected on the chromosomes of all three isolates but not on the plasmids. Fluoroquinolone-modifying factors [QnrA, QnrB, QnrS or AAC(6')-Ib-cr] were not detected. The results of RAPD analysis, combined with data on antimicrobial susceptibility, indicated that each isolate was unique. In conclusion, the emergence of ESBL-producing isolates of S. sonnei has been demonstrated for the first time in Lebanon. The resistance of these isolates to third-generation cephalosporins was mediated by the CTX-M-15 enzyme, which was plasmid-encoded.

Effects of subinhibitory concentrations of antimicrobial agents on Escherichia coli O157:H7 Shiga toxin release and role of the SOS response

Treatment of Escherichia coli O157:H7 by certain antimicrobial agents often exacerbates the patient's condition by increasing either the release of preformed Shiga toxins (Stx) upon cell lysis or their production through the SOS response-triggered induction of Stx-producing prophages. Recommended subinhibitory concentrations (sub-MICs) of azithromycin (AZI), gentamicin (GEN), imipenem (IMI), and rifampicin (RIF) were evaluated in comparison to norfloxacin (NOR), an SOS-inducer, to assess the role of the SOS response in Stx release. Relative expression of recA (SOS-inducer), Q (late antitermination gene of Stx-producing prophage), stx1, and stx2 genes was assessed at two sub-MICs of the antimicrobials for two different strains of E. coli O157:H7 using reverse transcription-real-time polymerase chain reaction. Both strains at the two sub-MICs were also subjected to Western blotting for LexA protein expression and to reverse passive latex agglutination for Stx detection. For both strains at both sub-MICs, NOR and AZI caused SOS-induced Stx production (high recA, Q, and stx2 gene expression and high Stx2 production), so they should be avoided in E. coli O157:H7 treatment; however, sub-MICs of RIF and IMI induced Stx2 production in an SOS-independent manner except for one strain at the first twofold dilution below MIC of RIF where Stx2 production decreased. Moreover, GEN caused somewhat increased Stx2 production due to its mode of action rather than any effect on gene expression. The choice of antimicrobial therapy should rely on the antimicrobial mode of action, its concentration, and on the nature of the strain.

Dentistry a second time?

INTRODUCTION

Dentistry in Jordan is an attractive profession due to the high social standard it provides. This study aimed to investigate whether dentists would choose dentistry again and whether their professional expectations would change after years of practice. Of special interest were possible differences according to gender, age, degree and place of work.

METHODS

A self-completion questionnaire was filled by a stratified random sample of 355 dentists in Jordan using closed questions. The questionnaire included professional, social and economic factors that influenced people's choice of dentistry and whether they would choose it again and the reasons for that.

RESULTS

The results showed that 52% of dentists who returned the questionnaire had dentistry as their first choice; the most important determining factor was the dentist's grades in the general secondary education. Fifty-two per cent stated that they would not choose it for the second time, the main reason being the health problems acquired through the profession and the low income. Helping others and the social standard dentistry provides were the main reasons given for dentists to choose dentistry again.

CONCLUSION

We report that more than half of the dentists included in this study would not 'choose dentistry again' as their profession regardless of age, gender and degree. This is mainly due to health problems acquired and the low income. We found that job satisfaction is highly affected by the workplace, and that more females are dissatisfied by the profession. This suggests that cultural background strongly affects the career decision.

Genotypes and serotype distribution of macrolide resistant invasive and non-invasive Streptococcus pneumoniae isolates from Lebanon

Background

This study determined macrolide resistance genotypes in clinical isolates of Streptococcus pneumoniae from multiple medical centers in Lebanon and assessed the serotype distribution in relation to these mechanism(s) of resistance and the source of isolate recovery.

Methods

Forty four macrolide resistant and 21 macrolide susceptible S. pneumoniae clinical isolates were tested for antimicrobial susceptibility according to CLSI guidelines (2008) and underwent molecular characterization. Serotyping of these isolates was performed by Multiplex PCR-based serotype deduction using CDC protocols. PCR amplification of macrolide resistant erm (encoding methylase) and mef (encoding macrolide efflux pump protein) genes was carried out.

Results

Among 44 isolates resistant to erythromycin, 35 were resistant to penicillin and 18 to ceftriaxone. Examination of 44 macrolide resistant isolates by PCR showed that 16 isolates harbored the erm(B) gene, 8 isolates harbored the mef gene, and 14 isolates harbored both the erm(B) and mef genes. There was no amplification by PCR of the erm(B) or mef genes in 6 isolates. Seven different capsular serotypes 2, 9V/9A,12F, 14,19A, 19F, and 23, were detected by multiplex PCR serotype deduction in 35 of 44 macrolide resistant isolates, with 19F being the most prevalent serotype. With the exception of serotype 2, all serotypes were invasive. Isolates belonging to the invasive serotypes 14 and 19F harbored both erm(B) and mef genes. Nine of the 44 macrolide resistant isolates were non-serotypable by our protocols.

Conclusion

Macrolide resistance in S. pneumoniae in Lebanon is mainly through target site modification but is also mediated through efflux pumps, with serotype 19F having dual resistance and being the most prevalent and invasive.

Decrease in Shiga toxin expression using a minimal inhibitory concentration of rifampicin followed by bactericidal gentamicin treatment enhances survival of Escherichia coli O157:H7-infected BALB/c mice

Background

Treatment of Escherichia coli O157:H7 infections with antimicrobial agents is controversial due to an association with potentially fatal sequelae. The production of Shiga toxins is believed to be central to the pathogenesis of this organism. Therefore, decreasing the expression of these toxins prior to bacterial eradication may provide a safer course of therapy.

Methods

The utility of decreasing Shiga toxin gene expression in E. coli O157:H7 with rifampicin prior to bacterial eradication with gentamicin was evaluated in vitro using real-time reverse-transcription polymerase chain reaction. Toxin release from treated bacterial cells was assayed for with reverse passive latex agglutination. The effect of this treatment on the survival of E. coli O157:H7-infected BALB/c mice was also monitored.

Results

Transcription of Shiga toxin-encoding genes was considerably decreased as an effect of treating E. coli O157:H7 in vitro with the minimum inhibitory concentration (MIC) of rifampicin followed by the minimum bactericidal concentration (MBC) of gentamicin (> 99% decrease) compared to treatment with gentamicin alone (50-75% decrease). The release of Shiga toxins from E. coli O157:H7 incubated with the MIC of rifampicin followed by addition of the MBC of gentamicin was decreased as well. On the other hand, the highest survival rate in BALB/c mice infected with E. coli O157:H7 was observed in those treated with the in vivo MIC equivalent dose of rifampicin followed by the in vivo MBC equivalent dose of gentamicin compared to mice treated with gentamicin or rifampicin alone.

Conclusions

The use of non-lethal expression-inhibitory doses of antimicrobial agents prior to bactericidal ones in treating E. coli O157:H7 infection is effective and may be potentially useful in human infections with this agent in addition to other Shiga toxin producing E. coli strains.

Stability and reproductive fitness of Schistosoma mansoni isolates with decreased sensitivity to praziquantel

These studies are focused on schistosomes derived from human infections not cured by three successive doses of praziquantel that also produced infections in mice that were significantly more difficult to cure than infections with control worms. Half (three of six) of these isolates retained their decreased response to praziquantel after multiple passages through the life-cycle in the absence of therapeutic pressure. Two of the isolates, including the one initially least sensitive to praziquantel; reverted, to a sensitivity not significantly different from controls. For example, the EE6 isolate initially required 680 mg/kg praziquantel to affect a 50% reduction in worm load in murine infections, but after only six passages through the life cycle over 5 years this was reduced to 113 mg/kg, not different from control infections. The stability of some of the isolates and the reversion of others indicates that the biological or genetic factors conferring decreased praziquantel response varies among the isolates. The three isolates that retained decreased sensitivity to praziquantel all showed compromises in reproductive fitness in the laboratory, expressed most frequently as a decreased cercarial production from snails infected with those isolates compared to controls. For example, the total cercarial production of snails infected with the EE10 isolate was only 57% that of controls. The reversion of some of the isolates to a praziquantel sensitive state and the decreased reproductive fitness of those that did not revert suggest that there is some biological cost associated with the relative praziquantel insensitivity of these worms, which could help limit the impact of such isolates in the field. Infections with the less sensitive isolates also produced significantly less circulating schistosomal antigen in mice, suggesting that a decrease in the host immune response elicited by these worms could be one of the factors contributing to the diminished praziquantel efficacy.

The carpal tunnel syndrome: diagnostic utility of the history and physical examination findings

STUDY OBJECTIVE

To assess the value of a history and physical examination findings in diagnosing the carpal tunnel syndrome, and to determine whether constellations of clinical findings identify patients at high or low risk for the carpal tunnel syndrome.

DESIGN

Comparison of diagnostic tests with neurophysiologic testing.

SETTING

Patients with upper extremity complaints of diverse causes referred to a neurophysiology laboratory for diagnostic studies.

METHODS

Before nerve conduction testing, a history, demographic and physical examination data, and a hand pain diagram were obtained from each patient. Diagrams were categorized as indicating the classic carpal tunnel syndrome, or as probable, possible, or unlikely to indicate the carpal tunnel syndrome. Associations between clinical data and nerve conduction results were examined in univariate and multivariate analyses.

RESULTS

Of 110 patients in the study, 44 (40%) had the carpal tunnel syndrome. Individually, the best predictors were hand pain diagram rating (positive predictive value, 0.59; 95% CI, 0.48 to 0.68) and Tinel sign (positive predictive value, 0.55, CI, 0.45 to 0.65). The combination of a positive Tinel sign and a probable or classic diagram rating had a positive predictive value of 0.71; CI, 0.53 to 0.85. Other findings from physical examination and the history were less useful. Just 9% of patients under 40 years of age with possible or unlikely diagram ratings had the carpal tunnel syndrome.

CONCLUSIONS

With the exceptions of age, Tinel sign, and hand pain diagram rating, findings from the physical examination and the history had limited diagnostic utility. Patients under 40 years of age with possible or unlikely diagram ratings were at low risk for the carpal tunnel syndrome. This finding, which should be confirmed in an independent population, suggests that subsets of patients may be managed without nerve conduction studies.

Comparison of blood levels of histamine and total ascorbic acid in pre-eclampsia with normal pregnancy

Levels of histamine and total ascorbic acid (L-ascorbic acid plus dehydroascorbic acid) in the peripheral blood of women in pre-eclampsia have been measured. The results show that blood histamine is increased both in the moderate and severe form of pre-eclampsia. Blood ascorbic acid on the other hand is increased only in the severe form of pre-eclampsia. The rise in histamine values may be in response to the rising blood pressure in pre-eclampsia. The rise in ascorbic acid values may reflect the reduced maternal blood volume and/or restricted transport of ascorbic acid from maternal to fetal tissues.

Hemostatic system changes induced by 50 micrograms and 30 micrograms estrogen/progestogen oral contraceptives. Modification of estrogen effects by levonorgestrel

Three oral contraceptive preparations were compared for effects on blood coagulation, fibrinolysis and platelet function in a total of 86 healthy young women. Two of the preparations contained 30 micrograms ethinyl estradiol combined with levonorgestrel or norethindrone acetate, and the third contained 50 micrograms mestranol and norethindrone. Tests were conducted before use of the agents, at intervals over 48 weeks' use and after discontinuation. This study showed that the changes in coagulation activity and fibrinolysis were largely related to the dose of estrogen in the contraceptive preparation; the smallest changes occurred with the low-dose (30 micrograms) preparations. This study also showed that changes occurring in certain coagulation factors and inhibitors were significantly smaller in the preparation containing 30 micrograms of ethinyl estradiol combined with levonorgestrel, suggesting that the progestogen used in these combination oral contraceptives modifies the estrogen effects.

The pediatric corner: the varied manifestations of Crohn's disease in children and adolescents

Thirty children less than 15 years of age with Crohn's disease are reported. The mean age of onset was nine years and five months. Delay in diagnosis may stem from the varying modes of presentation. The mean delay in diagnosis was two years. Chronic diarrhea and/or recurrent abdominal pain associated with extraintestinal manifestations, particularly abnormalities of growth and development suggests the possibility of Crohn's disease in the pediatric age group. Involvement of the terminal ileum occurred in 29 of the 30 patients. In addition, colonic disease occurred in 13 and jejunal involvement in one. Four patients presented with an acute onset of their disease. A favorable response to either medical or surgical therapy occurred in all four. Twenty-six patients had an insidious onset and tended to have a chronic course despite either medical and/or surgical therapy. Thirteen patients had an intestinal resection, with recurrence occurring in three from 1-4 years postoperatively. To date there has been one death.