Personal protective equipment and antiviral drug use during hospitalization for suspected avian or pandemic influenza

In a pandemic, many current national stockpiles of PPE and antiviral medications are likely inadequate.

For pandemic influenza planning, realistic estimates of personal protective equipment (PPE) and antiviral medication required for hospital healthcare workers (HCWs) are vital. In this simulation study, a patient with suspected avian or pandemic influenza (API) sought treatment at 9 Australian hospital emergency departments where patient–staff interactions during the first 6 hours of hospitalization were observed. Based on World Health Organization definitions and guidelines, the mean number of “close contacts” of the API patient was 12.3 (range 6–17; 85% HCWs); mean “exposures” were 19.3 (range 15–26). Overall, 20–25 PPE sets were required per patient, with variable HCW compliance for wearing these items (93% N95 masks, 77% gowns, 83% gloves, and 73% eye protection). Up to 41% of HCW close contacts would have qualified for postexposure antiviral prophylaxis. These data indicate that many current national stockpiles of PPE and antiviral medication are likely inadequate for a pandemic.

Surface microhardness of a nanofilled resin composite: a comparison of a tungsten halogen and a light-emitting diode light curing unit, in vitro

Surface microhardness numbers (VHN) have been measured and compared for disk specimens (thickness 1.5 mm) of a commercial nanofilled resin composite cured using a range of exposure times with a quartz tungsten halogen (QTH) and light-emitting diode (LED) light-curing unit (LCU), respectively. Each LCU requires different minimum exposure times to optimise VHN with respect to the internal controls but yield bottom surface/top surface VHN ratios > 0.95 with these optimised exposure times. Both LCUs produce comparable VHNs for the top surfaces at short exposure times but the QTH LCU requires increased exposure time for comparable results with the bottom surfaces. Overall, the LCUs are capable of producing comparable VHN numbers and VHN ratios within the parameters investigated.

Sympathetic vasoconstrictor regulation of mouse colonic submucosal arterioles is altered in experimental colitis

Recent studies suggest that altered neural regulation of the gastrointestinal microvasculature contributes to the pathogenesis of inflammatory bowel disease. Therefore, we employed video microscopy techniques to monitor nerve-evoked vasoconstrictor responses in mouse colonic submucosal arterioles in vitro and examined the effect of 2,4,6-trinitrobenzene sulphonic acid (TNBS) colitis. Nerve stimulation (2-20 Hz) caused frequency-dependent vasoconstrictor responses that were abolished by tetrodotoxin (300 nm) and guanethidine (10 microm). The P2 receptor antagonist suramin (100 microm) or the alpha(1)-adrenoceptor antagonist prazosin (100 nm) reduced the vasoconstriction and the combination of suramin and prazosin completely abolished responses. Nerve-evoked constrictions of submucosal arterioles from mice with TNBS colitis were inhibited by prazosin but not suramin. Superfusion of ATP (10 microm) resulted in large vasoconstrictions in control mice but had no effect in mice with colitis whereas constrictions to phenylephrine (3 microm) were unaffected. P2X(1) receptor immunohistochemistry did not suggest any alteration in receptor expression following colitis. However, Western blotting revealed that submucosal P2X(1) receptor expression was increased during colitis. In contrast to ATP, alphabeta-methylene-ATP (1 microm), which is resistant to catabolism by nucleotidases, constricted control and TNBS arterioles. This indicates that reduced purinergic transmission to submucosal arterioles may be due to increased degradation of ATP during colitis. These data comprise the first description of the neural regulation of mouse submucosal arterioles and identify a defect in sympathetic regulation of the GI vasculature during colitis due to reduced purinergic neurotransmission.

RNA interference-mediated suppression and replacement of human rhodopsin in vivo

Mutational heterogeneity represents a significant barrier to development of therapies for many dominantly inherited diseases. For example, >100 mutations in the rhodopsin gene (RHO) have been identified in patients with retinitis pigmentosa (RP). The development of therapies for dominant disorders that correct the primary genetic lesion and overcome mutational heterogeneity is challenging. Hence, therapeutics comprising two elements--gene suppression in conjunction with gene replacement--have been investigated. Suppression is targeted to a site independent of the mutation; therefore, both mutant and wild-type alleles are suppressed. In parallel with suppression, a codon-modified replacement gene refractory to suppression is provided. Both in vitro and in vivo validation of suppression and replacement for RHO-linked RP has been undertaken in the current study. RNA interference (RNAi) has been used to achieve ~90% in vivo suppression of RHO in photoreceptors, with use of adeno-associated virus (AAV) for delivery. Demonstration that codon-modifed RHO genes express functional wild-type protein has been explored transgenically, together with in vivo expression of AAV-delivered RHO-replacement genes in the presence of targeting RNAi molecules. Observation of potential therapeutic benefit from AAV-delivered suppression and replacement therapies has been obtained in Pro23His mice. Results provide the first in vivo indication that suppression and replacement can provide a therapeutic solution for dominantly inherited disorders such as RHO-linked RP and can be employed to circumvent mutational heterogeneity.

Development of strategies for conditional RNA interference

BACKGROUND

RNA interference (RNAi) represents a powerful tool with which to undertake sequence-dependent suppression of gene expression. Synthesized double-stranded RNA (dsRNA) or dsRNA generated endogenously from plasmid or viral vectors can be used for RNAi. For the latter, polymerase III promoters which drive ubiquitous expression in all tissues have typically been adopted. Given that dsRNA molecules must contain few 5' and 3' over-hanging bases to maintain potency, employing polymerase II promoters to drive tissue-specific expression of RNAi may be problematic due to potential inclusion of nucleotides 5' and 3' of siRNA sequences.

METHODS

To circumvent this, polymerase II promoters in combination with cis-acting hammerhead ribozymes and short-hairpin RNA sequences have been explored as a means to generate potent dsRNA molecules in tissues defined by the promoter in use.

RESULTS

The novel constructs evaluated in this study produced functional siRNA which suppressed the enhanced green fluorescent protein (eGFP) both in vitro and in vivo (in mice). Additionally, the constructs did not appear to elicit a significant type-1 interferon response compared to traditional H1-transcribed shRNA.

CONCLUSIONS

Given the potential 'off-target' effects of dsRNAs, it would be preferable in many cases to limit expression of dsRNA to the tissue of interest and moreover would significantly augment the resolution of RNAi technologies. Notably, the system under evaluation in this study could readily be adapted to achieve this objective.

RNAi-based suppression and replacement of rds-peripherin in retinal organotypic culture

Extensive mutational heterogeneity presents a significant barrier to the development of therapeutics for RDS-peripherin-linked autosomal-dominant retinitis pigmentosa (RP), for which more than 50 disease-related mutations have been identified to date. Mutation-independent suppression, using RNA interference (RNAi), together with simultaneous expression of a replacement rds gene (r-rds, which has been altered to escape suppression but nevertheless encodes wild-type protein) has been explored in COS-7 cells and mouse retinal explants. The efficacy of small interfering and short hairpin RNAs (si/shRNAs) silencing mouse rds, and the function of r-rds (containing degenerate substitutions in the RNAi target sequence) were analyzed at transcript (RT-PCR) and protein (ELISA) levels in COS-7 cells. "Dual-" and "triple-expression" constructs carrying the shRNA suppressor and the marker EGFP with or without the r-rds cassette were electroporated in vitro into retinal explants from 1-day-old pups. The retinae were dissociated at day 14, and transduced cells were FACS-sorted using the coexpressed EGFP marker and analyzed by RT-PCR. si/shRNAs decreased rds mRNA and protein expression by up to 82%, while r-rds was protected from suppression in COS-7 cells. Similarly, efficient RNAi-mediated suppression of endogenous rds was detected in retinal explants, while concomitant rescue of r-rds was also achieved. These data validate the concept of RNAi-based suppression coupled with replacement technology for the development of therapies targeting RDS-linked autosomal-dominant RP, and suggest that such approaches could potentially be used for other autosomal-dominant diseases with similarly extensive intragenic heterogeneity.

Screening for Chlamydia trachomatis in asymptomatic women attending outpatient clinics in a large maternity hospital in Dublin, Ireland

BACKGROUND

Chlamydia trachomatis can cause a sexually transmitted infection, which, untreated, may result in considerable morbidity.

METHODS

A prevalence study was conducted for C trachomatis using nucleic acid amplification technology in asymptomatic women, and certain risk factors that may be used to direct future screening strategies were assessed.

RESULTS

The study population comprised 945 asymptomatic women, of whom 783 were attending antenatal clinics, 91 were attending infertility clinics and 71 were attending family planning clinics. An overall C trachomatis prevalence of 3.7% (35/945) was found, with the highest prevalence of 11.2% (22/196) in Irish single women aged <25 years. Logistic regression analysis showed that single status and age <25 years were independent, statistically significant predictors of C trachomatis infection.

CONCLUSION

These results support routine screening of asymptomatic women who are sexually active and aged <25 years. An opportunist active screening of all sexually active women independent of age should be additionally considered if resources permit.

Investigation of avian influenza (H5N1) outbreak in humans--Thailand, 2004

INTRODUCTION

Beginning in late 2003, a substantial outbreak of influenza A (H5N1) virus spread among poultry in Thailand. On January 23, 2004, the Ministry of Public Health (MPH) detected the first confirmed human case of H5N1 infection in humans.

METHODS

During February-November 2004, the MPH's Bureau of Epidemiology and provincial health offices worked together to investigate the H5N1 outbreak in humans. Two studies were conducted: a descriptive study to describe clinical manifestations and epidemiologic characteristic of the cases and a matched case-control study to determine risk factors for persons who might subsequently become ill with H5N1.

RESULTS

A total of 16 patients with confirmed H5N1 were identified for the case-control study. Fever and respiratory symptoms predominated. Leucopenia and thrombocytopenia were present respectively in nine (100%) and four (44%) persons aged <15 years. Direct touching of unexpectedly dead poultry was the most significant risk factor (odds ratio = 29.0; 95% confidence interval = 2.7-308.2). Overall mortality was 75%; mortality for persons aged <15 years was 90%, compared with 57% for persons aged > or =15 years.

CONCLUSION

Avian influenza was more severe in children, who should avoid handling dead poultry during epizootics. Early avian influenza in children resembled the more common dengue fever, but presence of cough and absence of hemoconcentration distinguished avian influenza, which often progressed rapidly to acute respiratory distress syndrome, requiring intensive care.

Effect of triclosan on the development of bacterial biofilms by urinary tract pathogens on urinary catheters

OBJECTIVES

To examine (i) the effect of triclosan on the formation of catheter biofilms by urinary tract pathogens and (ii) the diffusion of triclosan through the retention balloons of urinary catheters.

METHODS

Models of the catheterized bladder were infected with eight different urinary tract pathogens and the effect of triclosan on biofilm formation was assessed by determining the numbers of viable cells colonizing the catheters and by scanning electron microscopy. HPLC was used to determine the triclosan concentration in urine draining from models that had been fitted with triclosan-inflated silicone catheters.

RESULTS

When catheters were inflated with triclosan (10 g/L) the formation of catheter biofilm by Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Proteus mirabilis was prevented. The numbers of Enterococcus faecalis and Providencia stuartii cells colonizing catheters were also significantly reduced (P<0.05). Serratia marcescens, Morganella morganii and Pseudomonas aeruginosa, however, were able to produce extensive catheter biofilms in the presence of triclosan. Only P. mirabilis produced alkaline urine and encrusted the catheters. Concentrations of 0.02-0.16 mg/L of the biocide were detected in urine draining from the model over the 48 h experimental period.

CONCLUSIONS

Triclosan diffused through silicone catheter balloons and produced urinary concentrations that prevented catheter encrustation by P. mirabilis and biofilm formation by several other common pathogens of the catheterized urinary tract. It had little effect on urease-producing P. aeruginosa, S. marcescens or M. morganii but these species did not produce alkaline urine or crystalline biofilms.

Sensory peptide neurotransmitters mediating mucosal and distension evoked neural vasodilator reflexes in guinea pig ileum

The aim was to determine the role CGRP and/or tachykinins released from sensory neural mechanisms in enteric neural vasodilator pathways. These pathways project through the myenteric plexus to submucosal vasodilator neurons. Submucosal arterioles were exposed in the distal portion of an in vitro combined submucosal-myenteric guinea pig ileal preparation, and dilation was monitored with videomicroscopy. Vasodilator neural reflexes were activated by gently stroking the mucosa with a fine brush or by distending a balloon placed beneath the flat-sheet preparation in the proximal portion. Dilations evoked by mucosal stroking were inhibited 64% by the CGRP 8-37 and 37% by NK3 (SR 142801) antagonists. When the two antagonists were combined with hexamethonium, only a small vasodilation persisted. Balloon distension-evoked vasodilations were inhibited by NK3 antagonists (66%) but were not altered by CGRP 8-37. In preparations in which myenteric descending interneurons were directly activated by electrical stimulation, combined application of CGRP 8-37 and the NK antagonists had no effect. Stimulation of capsaicin sensitive nerves in the myenteric plexus did not activate these vasodilator reflexes. These findings suggest that mucosal-activated reflexes result from the release of CGRP and tachykinins from enteric sensory neurons. Distension-evoked responses were significantly blocked by NK3 antagonists, suggesting that stretch activation of myenteric sensory neurons release tachykinins that activate NK3 receptors on myenteric vasodilator pathways.

Three-year follow-up of a family support service cohort of children with behavioural problems and their parents

Abstract Background The aim of this study was to establish the medium-term (three-year) psychosocial outcome of children with behavioural problems and their parents, who had received an intervention from a family support service. Methods Forty families were traced at the three-year follow-up and agreed to participate. Pre- and post-intervention and follow-up measures were the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) and the Strengths and Difficulties Questionnaire (SDQ). Results The primary HoNOSCA outcome items (i.e. those initially targeted by the parenting intervention) of aggression/antisocial behaviour and family relationships were not found to have changed significantly from the baseline (but had not sustained the sort-term improvement following the intervention). Deterioration was found in other HoNOSCA items such as overactivity, self-harm, scholastic/language skills, emotional, and poor school attendance. When we compared pre-intervention with follow-up SDQ scores, there was no significant change on any scales, i.e. these had returned to the level reported at the time of the original referral to the family support service. Conclusions Following the intervention from a family support service, children and families reported a significant improvement in most outcome measures, predominantly child behaviour and family relationships. However, these improvements were either not sustained or there were additional difficulties at three-year follow-up. These could be related to various external and developmental factors. This lack of sustainable treatment effects for children with behavioural problems is consistent with previous research findings on parenting programmes.

Acute lateral dislocation of the patella: correlation of ultrasound scanning with operative findings

Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella. Following non-operative management there is a re-dislocation rate of up to 44%. The purpose of this study was to test whether sonography is a reliable method of assessing the medial retinaculum after acute dislocation of the patella. Ten patients following acute patellar dislocation had an ultrasound scan (USS) performed by an experienced musculoskeletal radiologist. Each patient subsequently had an examination under anaesthetic, arthroscopy, and repair of the ruptured structures. The ultrasound reports were compared to the surgical findings to determine the accuracy of this investigation. USS located deficiencies in the ligamentous attachments to the medial border of the patella and the presence of avulsed bony fragments, all of which were confirmed at operation. The sonographic diagnosis of haematoma or torn fibres in the vastus medialis obliquus (VMO) corresponded with our operative findings. The most significant findings were the correlation of free fluid around the medial collateral ligament (MCL) with avulsion of the femoral attachment of the medial patellofemoral ligament (MPFL) and the presence of avulsed fragments of bone from the medial border of the patella.

Physician knowledge of the diagnosis and management of Rocky Mountain spotted fever: Mississippi, 2002

Rocky Mountain spotted fever (RMSF), a tick-borne illness that has its highest incidence in the south central and southeastern United States, is often a diagnostic challenge, as patients frequently present with nonspecific symptoms during the early stages of illness. RMSF has a high case fatality rate among untreated individuals, and the median time from onset of symptoms to death is only eight days, making early recognition and treatment of RMSF crucial. In two Mississippi public health districts, 148 primary care physicians were randomly selected and mailed surveys regarding RMSF diagnosis, treatment, and prevention. Eighty-four of the 148 (57%) physicians responded. Responses from different specialties and different health districts were compared using chi square statistics. Almost all (99%) physicians correctly identified doxycycline as the antibiotic agent of choice for treating adults and adolescents. However, only 21% of family practice physicians, and 25% of emergency medicine physicians correctly identified the antibiotic of choice for treating children with RMSF. Twenty-three percent of physicians responded that waiting for the development of a rash before prescribing antibiotics is an appropriate treatment strategy. The current standard of care-doxycycline as the agent of choice among children 8 years of age or younger with suspected RMSF-has not been effectively communicated to all physicians caring for children. Also, many physicians are not familiar with the rationale underlying initiation of antibiotic therapy prior to the development of rash in patients with suspected RMSF. Continuing education efforts should focus on antibiotic selection in pediatric patients and initiation of therapy prior to the onset of rash in appropriate patients.

Essential Bacillus subtilis genes

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

CNS listeriosis confused with leptomeningeal carcinomatosis in a patient with a malignant insulinoma

We describe a case of presumed listeria monocytogenes rhomboencephalitis, which was initially confused with leptomeningeal carcinomatosis in a patient with a malignant carcinoid tumor. Long-term corticosteroid treatment and immunosuppression caused by malignancy predisposed the patient to developing listeriosis. The clinical and radiologic features of this illustrative case are described. Listeriosis is an important treatable differential diagnosis in patients with malignancy presenting with neurologic signs.

Recurrent urinary tract infection in the female

PURPOSE OF REVIEW

Recurrent urinary tract infection is a common problem and can affect women of all ages, particularly the elderly and pregnant women. Obstetricians and gynaecologists need to have up-to-date knowledge of the diagnosis, pathophysiology and management of this condition.

RECENT FINDINGS

The diagnosis of urinary tract infection is made on the basis of symptoms and bacteriuria of more than 103 bacteria per ml. Host and bacterial virulence factors are important in the pathogenesis of recurrent urinary tract infections. General host factors predisposing to recurrent infection are genetic factors, ageing, the menopause, urogenital dysfunction, sexual behaviour, and previous pelvic surgery. Urinary tract infection is common in pregnancy, and recent studies have suggested an association with mental retardation and developmental delay. Women with recurrent urinary tract infection in pregnancy should be considered for long-term antibiotic prophylaxis. Intravaginal oestrogens and cranberry juice have been found to be effective for prevention, although more research is required. Women with recurrent urinary tract infection should have at least a 3-day course of trimethoprim or cotrimoxazole, or a 5-day course of beta-lactams or nitrofurantoin, with perhaps a 10-day course in the elderly. Women with frequent urinary tract infection (more than three episodes per year) should be offered prophylactic antibiotics, which can be patient-initiated, postcoital, or long-term low-dose therapy. In the future, vaccines against specific uropathogenic bacteria may be useful in urinary tract infection prophylaxis.

SUMMARY

More research is required, by all medical disciplines, on various aspects of urinary tract infection.

Characteristics of a large cluster of vancomycin-resistant enterococci in an Australian hospital

Investigation of a cluster of hospital inpatients colonized with vancomycin-resistant enterococci (VRE) revealed a point-prevalence of 19.1%. The outbreak was controlled using established guidelines and additional strategies, including minimizing patient transfers and enforcing appropriate antibiotic prescribing. The incidence of VRE has remained low during the ensuing 30 months.