Impact of larviciding with a Bacillus thuringiensis israelensis formulation, VectoBac WG, on dengue mosquito vectors in a dengue endemic site in Selangor State, Malaysia

The field bioefficacy of a wettable granule (WG) formulation of Bacillus thuringiensis israelensis (Bti), VectoBac WG (Bti strain AM65-52) against dengue vectors, Aedes aegypti and Ae albopictus; was evaluated in a suburban residential area (TST) and in a temporary settlement site (KB) in the state of Selangor, Malaysia. Pre-control ovitrap surveillance of the trial sites indicated a high population of both types of Aedes mosquitoes. The populations were monitored continuously by weekly ovitrapping. Bti was sprayed biweekly at a dosage of 500 g/ha by using a mist-blower. The spray application was targeted into outdoor larval habitats. If required, Bti formulation was also applied directly into indoor water-holding containers at 8 g/1,000 l. Based on ovitrap surveillance, a significant reduction in Aedes populations was evident 4 weeks after initiating the first Bti treatment. The ovitrap index (OI) and the larvae density decreased drastically in both trial sites. In TST, the indoor OI was significantly reduced from 57.50 +/- 7.50% to 19.13 +/- 5.49% (p<0.05), while the outdoor OI decreased from 38.89 +/- 11.11% to 15.36 +/- 5.93%. In KB, similarly, the OI was significantly reduced by more than half, from 66.66 +/- 6.67% to 30.26 +/- 2.99% (p< 0.05). In all cases, the reduction in OI was paralleled by reduction in larval density.

Defective ubiquitinylation of EGFR mutants of lung cancer confers prolonged signaling

Several distinct mutations within the kinase domain of the epidermal growth factor receptor (EGFR) are associated with non-small cell lung cancer, but mechanisms underlying their oncogenic potential are incompletely understood. Although normally ligand-induced kinase activation targets EGFR to Cbl-mediated receptor ubiquitinylation and subsequent degradation in lysosomes, we report that certain EGFR mutants escape this regulation. Defective endocytosis characterizes a deletion mutant of EGFR, as well as a point mutant (L858R-EGFR), whose association with c-Cbl and ubiquitinylation are impaired. Our data raise the possibility that refractoriness of L858R-EGFR to downregulation is due to enhanced heterodimerization with the oncogene product HER2, which leads to persistent stimulation.

A systematic review of randomized controlled trials for plasma exchange in the treatment of thrombotic thrombocytopenic purpura

The mainstay of treatment for thrombotic thrombocytopenic purpura (TTP) is plasma exchange (PE). A systematic review was undertaken to summarize the randomized controlled trial (RCT) evidence, to date, on PE as treatment for TTP. Seven randomized RCTs were identified till May 2005. A statistical reduction in mortality was found in patients receiving PE compared with patients receiving plasma infusion (relative risk 0.31, 95% confidence interval 0.12-0.79). No statistical difference in mortality was found in trials comparing different replacement fluids for PE. There were few differences in the response to treatment and the resolution of the presenting signs of TTP in any trial. Lack of data prevented a full assessment of the incidence of adverse events. None of the studies included measured patients' quality of life. Further research is required to determine the benefits and side effects associated with different replacement fluids for PE. It is recommended that there should be consistency in the diagnostic criteria, measurement of clinical outcomes and length of follow up. Continued support of existing TTP patient registries and establishment of new registries would facilitate this.

The three-dimensional structure of complex I from Yarrowia lipolytica: a highly dynamic enzyme

The structure of complex I from Yarrowia lipolytica was determined by three-dimensional electron microscopy. A random conical data set was collected from deep stain embedded particles. More than 14000 image pairs were analyzed. Through extensive classification combined with three-dimensional reconstruction, it was possible for the first time to show a much more detailed substructure of the complex. The peripheral arm is subdivided in at least six domains. The membrane arm shows two major protrusions on its matrix facing side and exhibits a channel like feature on the side facing the cytoplasm. Structures resembling a tether connecting the subunits near the catalytic center with the protrusions of the membrane arm provide a second connection between matrix and membrane domain.

Long-term results of radiofrequency ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia: single-center experience

BACKGROUND

This study sought to evaluate the long-term recurrence rate of atrioventricular nodal reentrant tachycardia (AVNRT) after radiofrequency catheter ablation. The clinical and electrophysiological features of patients with AVNRT and their immediate outcomes after undergoing slow pathway ablation/modification were also studied.

METHODS AND RESULTS

The study included 264 consecutive patients with AVNRT (mean age 46 -/+ 15 years, 143 women, 121 men) who underwent slow pathway ablation/modification using a combined electrophysiological and anatomical approach. The primary endpoint of ablation procedure was non- inducibility of the arrhythmia. The primary endpoint of the study was the recurrence of AVNRT on follow-up. Acute success was achieved in 262 (99.6%) patients. Complication rate of the ablation procedure was 2.6% and the average fluoroscopy time was 18.3 -/+ 11 minutes. The patients were followed up for a mean duration of 20 -/+ 9 months during which there was only one case of recurrence.

CONCLUSION

Radiofrequency ablation or modification of slow pathway is highly effective in the treatment of AVNRT. The technique has a high initial success rate and a low complication rate. The recurrence rates are extremely low (0.3%) on long-term follow-up.

Survey of the use and clinical effectiveness of HPA-1a/5b-negative platelet concentrates in proven or suspected platelet alloimmunization

The optimal treatment of neonatal alloimmune thrombocytopenia (NAIT) is the transfusion of compatible donor platelets. The National Blood Service in England has established panels of "accredited" donors negative for human platelet antigens HPA-1a and HPA-5b, the most commonly implicated alloantigens. We have retrospectively surveyed the frequency of use and clinical effectiveness of donations collected over a 13-month period from the Oxford accredited panel. Ninety-five per cent of hyperconcentrated platelets (HPCs) collected were issued, all for intrauterine transfusion to fetuses at risk of NAIT due to the presence of maternal platelet alloantibodies and previously affected siblings. Thirty-one per cent of paediatric platelet concentrates (PPCs) collected were issued, of which 57% were used for cases of suspected NAIT. Fifty-four per cent of adult therapeutic doses collected were issued; 5% of these were used in cases of suspected NAIT or proven post-transfusion purpura (PTP). Good increments were seen in most NAIT cases transfused with HPCs or PPCs, and a moderate increment in the one PTP case. We conclude that the establishment of accredited panels is justified and enables delivery of a clinically effective treatment for NAIT. Increased use and cost-effectiveness could be achieved by the delivery of an educational programme to neonatal unit clinical staff to increase the awareness and appropriate treatment of NAIT.

Associations between adverse events in childhood and chronic widespread pain in adulthood: are they explained by differential recall?

OBJECTIVE

Clinic based studies suggest that adverse events in childhood may predispose to chronic pain in adult life. These have been conducted on highly selected groups, and it is unknown whether these relationships hold in the general population and to what extent the increased rate of adverse childhood events in persons with pain is an artefact of differential reporting. We examined the hypothesis that chronic widespread pain was associated with reports of adverse experiences in childhood and whether any observed relationships could be explained by differential recall.

METHODS

A cross sectional population based screening survey was conducted. Subjects completed a questionnaire that included assessments of pain and psychological state. In total, 296 subjects who had demonstrated psychological distress were randomly selected and had a detailed interview, which included an assessment of 14 adverse childhood experiences. Medical records relating to childhood were also examined for those subjects.

RESULTS

The prevalence of self-reported adverse childhood experiences was greatest in adult subjects with current chronic widespread pain. Exposure to illness in family members, parental loss, operations, and abuse were all associated with increased, but nonsignificant, odds of having chronic widespread pain versus those without such exposures. However the only statistically significant association was with childhood hospitalizations. From medical record information the associations of hospitalizations (OR 5.1, 95% CI 2.0-13.0) and operations (OR 3.0, 95% CI 1.2-7.2) with pain previously noted were partly explained by differential recall between subjects with and without pain: hospitalizations, OR 2.2, 95% CI 0.9-5.5; operations, OR 1.2, 95% CI 0.5-3.4.

CONCLUSION

Although several reported adverse events in childhood were observed to be associated with chronic widespread pain in adulthood, only reports of hospitalizations were significantly associated. Validation of self-reported exposures suggests that there was differential recall of past events among those with and without pain, and this differential recall explained the association between hospitalizations and current chronic pain. Such differential recall may explain other observations of an association between reports of adverse childhood events and chronic pain in adulthood.

A case ascertainment study of septic discitis: clinical, microbiological and radiological features

We studied the spectrum of septic discitis presenting to two busy district general hospitals over 2.5 years (November 1996 to April 1999), surveying the case notes of all patients attending Royal Bournemouth and Poole Hospitals with probable septic discitis on magnetic resonance imaging (MRI). Twenty-two cases of septic discitis were identified, suggesting an annual incidence of 2/100 000/year. Seventy-three percent of patients were aged > or =65 years. In 91% of patients, back pain was the presenting symptom, with neurological signs evident in 45% of patients. Fever >37.5 degrees C was present in 68% of patients, and a marked elevation of erythrocyte sedimentation rate (ESR) in 91%. Diagnosis was originally by MRI in 86% of patients, with plain radiographs not diagnostic of discitis in the early stages of the infection. Staphylococcus aureus was the commonest pathogen (41%), but in 18% of patients, no organism was identified. The major predisposing factors to septic discitis were invasive procedures (41%), underlying cancer (25%) and diabetes (18%). Pre-existing degenerative spinal disease was found in 50% of patients. Four patients whose causative organism was not isolated had a poorer outcome: one death and three with increased morbidity. Our estimated incidence rate (2/100 000/year) is higher than that in previous studies and may be due to a higher detection rate with MRI and/or a genuine increase in the number of cases. Septic discitis should be considered in any patient who has severe localized pain at any spinal level, especially if accompanied by fever and elevated ESR, or in the immunosuppressed.

Features of somatization predict the onset of chronic widespread pain: results of a large population-based study

OBJECTIVE

Chronic widespread pain, the clinical hallmark of the fibromyalgia syndrome, is associated with other physical and psychological symptoms both in patients studied in a clinical setting and in those identified in the community. The present study was undertaken to examine the hypothesis that psychological and physical indicators of the process of somatization predict the development of new chronic widespread pain.

METHODS

In this population-based prospective study, 1,658 adults ages 18-65 years completed a detailed pain questionnaire, which included a pain drawing. They also completed the following psychosocial instruments: General Health Questionnaire, Somatic Symptom Checklist, Fatigue Questionnaire, and Illness Attitude Scales. Individuals were followed up at 12 months, at which time 1,480 (93% of subjects still living at their baseline address) provided data on pain status, using the same instruments.

RESULTS

At baseline, 825 subjects were classified as pain free and 833 as having pain not satisfying criteria for chronic widespread pain. Of those, 18 (2%) and 63 (8%), respectively, were classified as having chronic widespread pain at followup. After adjustment for age and sex, there were strong relationships between baseline test scores and subsequent risk of chronic widespread pain (odds ratio for the Somatic Symptom Checklist 3.3; odds ratio for the Illness Behavior subscale of the Illness Attitude Scales 9.0). All 95% confidence intervals excluded unity. These associations were independent of baseline pain status.

CONCLUSION

Subjects who are free of chronic widespread pain are at increased future risk of its development if they display other aspects of the process of somatization. Data from this population-based prospective study lend powerful support to the hypothesis that chronic widespread pain can be one manifestation of the somatization of distress.

A quality approach for conducting training needs assessments in the Ministry of Health, State of Bahrain

In health care organizations around the world, Training Needs Assessments (TNAs) have generally followed a professions-based approach. For example, the training needs of doctors, nurses, each allied health profession, and distinct support staff have been analyzed separately--individualized TNAs conducted for each speciality and functional area. Although a professions-based TNA model can provide useful information to human resource development (HRD) professionals, there are two major drawbacks: (1) it is possible that important training needs might be overlooked because of lack of information sharing among professions and (2) such an approach does not encourage an interdisciplinary, team orientation to service provision. This paper proposes an improved method of conceptualizing TNAs, using an approach that builds on the quality management literature (TQM, CQI, etc.) which stresses the importance of customer- and service-orientations to organizing and measuring organizational and individual performance.

Disability and mental health of patients waiting for total hip replacement

We performed a cross sectional study to examine the relationship between physical function and mental health of patients waiting for total hip replacement surgery, and the relationship between physical and social function and mental health to time spent waiting for surgery. We found that, in addition to the expected poor hip function, limited mobility and pain, one-quarter of the patients had clinically significant mood disorders and another quarter were in the borderline range. No association was found between severity of mental disorder and assessment of hip function. The patients had been waiting for 1-26 months (median 6 months) for surgery: yet those waiting longest were no worse on any of the outcome measures and their mental health was better. We conclude that mental disorders are common in patients waiting for hip replacements, are not directly related to hip function and their origins are unknown, but they require clinical assessment and treatment. There is no evidence that physical or social function or mental health are worse in those waiting longer for hip replacement surgery. Even so, these patients are severely disabled and some have to wait too long.

Effect of light/dark regimen on N-nitrosoethylurea-induced transplacental carcinogenesis in rats

Pregnant females were randomly subdivided into three groups (24 rats per group) and kept at the 12:12 h light/dark regimen (group 1), at the constant light illumination (24 h a day, group 2) or at the continuous darkness (group 3). N-nitrosoethylurea (NEU) has been injected into the tail vein of all rats (80 mg/kg) on the 18-19th day of the pregnancy. After the delivery the lacting dams and their progeny during the lactation period (1 month after delivery) were kept also at the three different light/dark regimens. Then all offspring from each group was kept at the 12:12 h light/dark regimen, males and females separately, and were observed until natural death. The exposure to constant light significantly promoted the transplacental carcinogenesis whereas the exposure to constant darkness inhibited it. The incidence of total tumors, tumors of both a peripheral nervous system and kidney was 2.6; 2.5 and 8.5 times higher, and survival significantly shorter, correspondingly, in rats from the group 2 exposed to the constant light regimen as compared to the group 1 (12:12 h light/dark regimen) (P<0.05). On the other hand, the exposure to the continuous darkness during the pregnancy and the lactation period significantly inhibited the transplacental carcinogenesis in the offspring of rats treated with NEU. The incidence of total tumors, tumors of a peripheral nervous system was by 2.4 and 2.7 times less, and survival longer, respectively, in exposed to the darkness rats from the group 3 as compared to the group 1 (12:12 h light/dark regimen) (P<0.05). Thus, our data firstly have shown the modifying effect of light-dark regimen on the realization of the transplacental carcinogenesis induced by NEU in rats.

Application of "VITALS": visual indicators of teaching and learning success in reporting student evaluations of clinical teachers

CONTEXT

At the College of Medicine and Medical Sciences, Arabian Gulf University, Bahrain, a system has been introduced in which clerkship students evaluate clinical faculty using Visual Indicators of Teaching and Learning Success (VITALS).

OBJECTIVE

To describe the use of VITALS in reporting student feedback on teaching and learning effectiveness of clinical faculty in the clerkship.

DESIGN

Descriptive study.

SUBJECTS

A total of 210 clerkship students evaluated 76 clinical tutors over a period of 3 years. Feedback was also obtained from seven programme managers and one supportive staff member.

METHOD

Nine indicators of effective clinical teaching were identified through a literature search. Students individually reported on clinical faculty teaching capabilities using a 5-point, Likert-type scale. Cumulative reports of students' feedback on clinical faculty teaching were prepared using opposing bar graphs, reflecting perceived areas of strength or weakness in each teacher's performance.

RESULTS

A total of 1450 evaluation forms were completed by 180 of 210 students (85.7%). VITALS graph representations of students' perceptions of clinical tutors were communicated to each clinical tutor at the end of each clerkship and academic year. Twenty-one students out of 53 who gave written comments were related to VITALS. They reflected a positive view of VITALS as a process or tool of faculty evaluation. Clinical faculty (18), programme managers(7) and supporting staff (1) gave comments indicating acceptance of the system.

CONCLUSION

This preliminary study suggests that VITALS could be an effective tool for improving clinical teaching. It is acceptable to students, faculty and managers of educational programmes. The database reflecting their teaching and educational profiles were used to provide clinical faculty with constructive feedback.

QUANTUM CRYPTOGRAPHY: Single Photons

Quantum cryptography offers the potential of totally secure transfer of information, but as Benjamin discusses in this Perspective, its practical implementation hinges on being able to generate single photons (rather than two or more) at a time. Michler et al. show how this condition can be met in a quantum dot microdisk structure. Single molecules were also recently shown to allow controlled single-photon emission.

Haematologists' approaches to the management of adolescents and young adults with acute leukaemia

Approaches to the management of adolescents and young adults with acute leukaemia were investigated by sending a questionnaire to hospitals identified as having diagnosed or treated patients aged 15-29 years. The responses demonstrated the types of hospital treating these patients, the haematologists' perceived practice for entry of patients to Medical Research Council (MRC) leukaemia trials and reasons for non-entry. Data were linked to MRC trials data to determine the proportion of patients aged 15-29 years at diagnosis in responding hospitals actually treated in MRC leukaemia trials in the 5 years preceding the questionnaire. Eighty-two per cent of haematologists stated that they entered patients 'always' or 'whenever possible' for acute myeloid leukaemia (AML) and 76% for acute lymphoblastic leukaemia (ALL), but actual entry rates from the study hospitals were 46% of 239 AML patients and 36% of 182 ALL patients. The reasons most commonly reported for not entering eligible patients to national leukaemia trials were clinician preference for one arm of an MRC trial, a regional study or non-trial protocol, and concern about workload and ethical approval.

An epidemic of congenital rubella in Barbados

Rubella and congenital rubella syndrome (CRS) are preventable, but epidemics of rubella and CRS are not infrequent in the Caribbean and other developing countries. As a result of a surveillance system initiated after an epidemic of rubella in the Barbadian population in 1996, cases of CRS were identified and investigated. A total of seven cases of CRS were proven to be rubella IgM-positive. The infants were found to have a mean birthweight of 2587 g and a mean gestational age of 38 weeks. The clinical course, complications and outcome of those infants were documented and the cost of acute hospital care for each patient was also recorded. Cataracts in four infants, congenital heart disease in three and central nervous system abnormalities in five were the major clinical abnormalities. In four infants, two or more clinical systems were affected. The combined total hospital stay was 105 days (mean 15, range 0-44). A national effort to immunize all those at risk and a strict surveillance programme are essential to prevent future epidemics. This would lead to a significant reduction in the number of cases of rubella and CRS and could effect substantial savings in the national health budget.

A certain fate: spread of HIV among young injecting drug users in Manipur, north-east India

This study aimed to measure risk behaviours and seroprevalence of HIV and hepatitis C virus in IDUs in Manipur, North-East India, and evaluate the impact of the recently established Syringe and Needle Exchange Program (SNEP). Sampling strategy was based on social networks. Peer interviewers administered the study questionnaire and collected blood for anti-HCV and anti-HIV testing. One hundred and ninety-one IDUs (85% male) took part. Average age at first injection was 19 years and average length of time injecting was 3.7 years. The main drug currently injected was heroin (66%). Most (93%) reported having shared injecting equipment and only 42% had used the SNEP. Three-quarters (74.7%) were infected with HIV and almost all (98%) with HCV. Age (p < 0.001) and length of time injecting (p < 0.001) were significantly associated with being HIV-positive. Over two-thirds were sexually active, but only 3% consistently used condoms. Almost three-quarters of IDUs in this study were infected with HIV, most within the first two years of injecting, indicating infection continues to spread at very high rates. Unsafe sexual practices place partners of infected IDUs at risk of infection. The SNEP must increase its coverage to young and new IDUs before they are exposed to blood-borne viruses.

Interference footprinting analysis of telomerase elongation complexes

Telomerase is a reverse transcriptase that adds single-stranded telomeric repeats to the ends of linear eukaryotic chromosomes. It consists of an RNA molecule including a template sequence, a protein subunit containing reverse transcriptase motifs, and auxiliary proteins. We have carried out an interference footprinting analysis of the Tetrahymena telomerase elongation complexes. In this study, single-stranded oligonucleotide primers containing telomeric sequences were modified with base-specific chemical reagents and extended with the telomerase by a single (32)P-labeled dGMP or dTMP. Base modifications that interfered with the primer extension reactions were mapped by footprinting. Major functional interactions were detected between the telomerase and the six or seven 3'-terminal residues of the primers. These interactions occurred not only with the RNA template region, but also with another region in the enzyme ribonucleoprotein complex designated the telomerase DNA interacting surface (TDIS). This was indicated by footprints generated with dimethyl sulfate (that did not affect Watson-Crick hydrogen bonding) and by footprinting assays performed with mutant primers. In primers aligned at a distance of 2 nucleotides along the RNA template region, the footprints of the six or seven 3'-terminal residues were shifted by 2 nucleotides. This shift indicated that during the elongation reaction, TDIS moved in concert with the 3' ends of the primers relative to the template region. Weak interactions occurred between the telomerase and residues located upstream of the seventh nucleotide. These interactions were stronger in primers that were impaired in the ability to align with the template.

Nonmalignant obstruction is a common problem with metal stents in the treatment of esophageal cancer

BACKGROUND

The use of metal stents for the treatment of dysphagia due to esophageal malignancy is an important advance because of ease of delivery and their self-expandable property. Obstruction due to tumor overgrowth is a recognized complication, but nonmalignant obstruction in patients with metal stents is rarely reported.

METHODS

Database records of patients who had esophageal cancer and underwent metal stent insertion were reviewed.

RESULTS

A total of 116 patients were seen between October 1993 and October 1997. Four types of metal stents had been used (Ultraflex, Z Stent, Wallstent, and Esophacoil). Detailed follow-up information was available for 81 patients, who constitute the study sample. Forty-nine (60%) stent obstructions were reported, 26 of the 49 (53%) were due to tumor overgrowth and 23 (47%) were not associated with malignancy. Histologic analysis of the nonmalignant obstructing tissue showed granulation tissue (56%), reactive hyperplasia (22%) and fibrosis (22%).

CONCLUSIONS

Nonmalignant obstruction is a common although infrequently reported complication after placement of metal stents for esophageal cancer. The tissue response of the esophageal mucosa occurred with all 4 types of stents used. No specific characteristic of the stent or prior treatment seems to be related to obstruction of the stent in patients with either nonmalignant obstruction or tumor overgrowth.