Model-based estimates of risks of disease transmission and economic costs of seven injection devices in sub-Saharan Africa.
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OBJECTIVE: To investigate and compare seven types of injection devices for their risks of iatrogenic transmission of bloodborne pathogens and their economic costs in sub-Saharan Africa. METHODS: Risk assumptions for each device and cost models were constructed to estimate the number of new hepatitis B virus (HBV) and human immunodeficiency virus (HIV) infections resulting from patient-to-patient, patient-to-health care worker, and patient-to-community transmission. Costs of device purchase and usage were derived from the literature, while costs of direct medical care and lost productivity from HBV and HIV disease were based on data collected in 1999 in Cote d'Ivoire, Ghana, and Uganda. Multivariate sensitivity analyses using Monte Carlo simulation characterized uncertainties in model parameters. Costs were summed from both the societal and health care system payer's perspectives. FINDINGS: Resterilizable and disposable needles and syringes had the highest overall costs for device purchase, usage, and iatrogenic disease: median US dollars 26.77 and US dollars 25.29, respectively, per injection from the societal perspective. Disposable-cartridge jet injectors and automatic needle-shielding syringes had the lowest costs, US dollars 0.36 and US dollars 0.80, respectively. Reusable-nozzle jet injectors and auto-disable needle and syringes were intermediate, at US dollars 0.80 and US dollars 0.91, respectively, per injection. CONCLUSION: Despite their nominal purchase and usage costs, conventional needles and syringes carry a hidden but huge burden of iatrogenic disease. Alternative injection devices for the millions of injections administered annually in sub-Saharan Africa would be of value and should be considered by policy-makers in procurement decisions. (+info)
The 'swoosh' test--an evaluation of a modified 'whoosh' test in children.
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BACKGROUND: Caudal analgesia is widely used in paediatric anaesthetic practice. In adults, the 'whoosh' test has been recommended as a guide to successful needle insertion, but it has not been extensively studied in paediatric patients. We have investigated a modification of the 'whoosh' test, which we have christened the 'swoosh' test. It avoids the injection of air by performing auscultation during injection of the local anaesthetic solution. We have compared it with clinical judgement of correct placement. METHODS: We studied 113 children undergoing elective surgery. During insertion of the caudal block, a stethoscope was placed over the lower lumbar spine and the presence or absence of an audible 'swoosh' noted. The operator's clinical impression of successful insertion was also recorded. RESULTS: The overall success rate of caudal anaesthesia was 95.6%. Of the 108 patients with a successful block, 98 had a positive 'swoosh' test. There were no false positive results. Calculations show the 'swoosh' test to have a sensitivity of 91%, a specificity of 100% and a positive predictive value of 100%. CONCLUSIONS: The 'swoosh' test is a simple and accurate test to confirm successful caudal insertion in children, and is especially useful as a teaching aid for anaesthetists new to the technique. (+info)
Transurethral prostatic tissue ablation via a single needle delivery system: initial experience with radio-frequency energy and ethanol.
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We report an initial clinical experience to evaluate the safety and efficacy of outpatient prostatic ablation for the treatment of symptomatic benign prostatic hyperplasia (BPH) using local anesthesia (OPAL) with radio-frequency energy and intraprostatic absolute ethanol injection (EI). Twenty-three patients were treated with OPAL and five patients were treated with EI. Pre-operative data for all patients included international prostate symptom score (IPSS), quality of life score (QL), maximum flow rate (Q(max)), and post void residual determination. Prostate specific antigen (PSA) and transrectal ultrasound prostate volume determination were also done for EI patients. Needle deployment into the prostate was carried out at the 2, 4, 8 and 10 o'clock positions for lateral lobe hyperplasia and the 6 o'clock position for middle lobe hyperplasia. IPSS, QL, Q(max) and post void residual data were collected at 1, 3, 6 and 12 months post procedure. Both procedures resulted in statistically significant reductions of IPSS and QL. Trends towards improvement were seen both for Q(max) and post void residual, with Q(max) significantly improved after OPAL. Among EI patients, the prostate volume was reduced at 6 months post treatment to 37.2+/-17.9 g from 53.0+/-19.0 g (P=0.03) preoperatively. OPAL was safe but suffered from a high re-treatment rate. EI demonstrated encouraging results with regards to safety, symptom improvement and prostate volume reduction. (+info)
Validating a new non-penetrating sham acupuncture device: two randomised controlled trials.
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For clinical trials of acupuncture, it would be desirable to have a sham procedure that is indistinguishable from the real treatment, yet inactive. A sham needle has been designed which telescopes instead of penetrating the skin. The Park Sham Device involves an improved method of supporting the sham needle and requires validation. The objective of these studies was to test whether the sham procedure using the new device was 1) indistinguishable from the same procedure using real needles in acupuncture naive subjects, and 2) inactive, where the specific needle sensation (de qi) is taken as a surrogate measure of activity. The studies were designed as subject and assessor blind, randomised controlled trials. Study 1) included 58 patients enrolled in a clinical trial of acupuncture for acute stroke. Study 2) included 63 healthy, acupuncture naive, adult volunteers. The interventions used were real or sham acupuncture using the Park Sham Device. Study 1) was set in a district general hospital, and study 2) in a university laboratory. The outcome measure in study 1) was the form of treatment that patients believed they had received. In study 2) the outcome measure was experience of de qi, as judged by three acupuncture experts. No patient in either group(study 1) believed he or she had been treated with the sham needle. In 40 volunteers (study 2) for whom experts achieved consensus, the relative risk of experiencing de qi with real acupuncture to that with sham acupuncture was 15.38 (95% CI 2.26 to 104.86). The inter-rater reliability of all 13 experts (study 2), calculated from their judgements on 10 subjects selected by randomisation, was 0.52 (95% CI 0.19 to 0.61). In conclusion, the results suggest that the procedure using the new device is indistinguishable from the same procedure using real needles in acupuncture naive subjects, and is inactive, where the specific needle sensation (de qi) is taken as a surrogate measure of activity. It is therefore a valid control for acupuncture trials. The findings also lend support to the existence of de qi, a major concept underlying traditional Chinese acupuncture. (+info)
Cells lying on a bed of microneedles: an approach to isolate mechanical force.
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We describe an approach to manipulate and measure mechanical interactions between cells and their underlying substrates by using microfabricated arrays of elastomeric, microneedle-like posts. By controlling the geometry of the posts, we varied the compliance of the substrate while holding other surface properties constant. Cells attached to, spread across, and deflected multiple posts. The deflections of the posts occurred independently of neighboring posts and, therefore, directly reported the subcellular distribution of traction forces. We report two classes of force-supporting adhesions that exhibit distinct force-size relationships. Force increased with size of adhesions for adhesions larger than 1 microm(2), whereas no such correlation existed for smaller adhesions. By controlling cell adhesion on these micromechanical sensors, we showed that cell morphology regulates the magnitude of traction force generated by cells. Cells that were prevented from spreading and flattening against the substrate did not contract in response to stimulation by serum or lysophosphatidic acid, whereas spread cells did. Contractility in the unspread cells was rescued by expression of constitutively active RhoA. Together, these findings demonstrate a coordination of biochemical and mechanical signals to regulate cell adhesion and mechanics, and they introduce the use of arrays of mechanically isolated sensors to manipulate and measure the mechanical interactions of cells. (+info)
Invasive intrauterine treatment of pulmonary atresia/intact ventricular septum with heart failure.
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The mortality and morbidity of children with pulmonary atresia/intact ventricular septum (PA/IVS) are linked to the degree of right ventricular (RV) hypoplasia. Opening up the pulmonary valve (PV) in fetal life could result in improved growth of the RV making it amenable to biventricular repair postnatally. Successful valvulotomy of the PV was performed in a fetus with heart failure at 28 weeks. Following the procedure there was significant growth of the tricuspid valve and RV. The neonate was delivered at 38 weeks with a RV suitable for biventricular repair. In utero pulmonary valvulotomy is feasible and may change the natural history of the condition in affected fetuses with PA/IVS. (+info)
Mechanical elongation of the centromere in the barley metaphase chromosome.
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The present study investigated the mechanical elongation of the centromere in the barley chromosomes by a microneedle manipulation method for the structural analysis of the chromosomes. Chromosomes were extracted from barley root cells, affixed on a cover slip by a standard preparation method, and elongated in either distilled water, phosphate buffered saline (PBS), or 2 x sodium saline citrate (SSC). The mechanical property of the chromosome elongation was assessed by the measurement of the force required for the elongation of chromosomes. This assessment has shown that the chromosomes in distilled water were much firmer than those in the PBS or 2 x SSC. To confirm the elongation of the centromere, the elongated chromosomes were investigated by fluorescence in situ hybridization with a centromere probe. The fluorescence information indicated that the extent of the loosening of the centromere during elongation differed depending on the buffers used; the centromere elongated in 2 x SSC was more loosened than that in the PBS. Atomic force microscopy also revealed the structure of the unpacked centromere after the mechanical elongation, when rows of fibrous structures about 30 to 50 nm thick were clearly observed in the centromere elongated in 2 x SSC. The investigation of elongated chromosomes should prove useful for an understanding of the structural analysis of chromosomes. (+info)
Expression of a luxS gene is not required for Borrelia burgdorferi infection of mice via needle inoculation.
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The luxS gene product is an integral component of LuxS/autoinducer-2 (AI-2) quorum-sensing systems in bacteria. A putative luxS gene was expressed at comparable levels by Borrelia burgdorferi strain 297 cultivated either in vitro or in dialysis membrane chambers implanted in rat peritoneal cavities. Although the borrelial luxS gene functionally complemented a LuxS deficiency in Escherichia coli DH5 alpha, AI-2-like activity could not be detected within B. burgdorferi culture supernatants or concentrated cell lysates. Finally, a luxS-deficient mutant of B. burgdorferi was infectious at wild-type levels when it was intradermally needle inoculated into mice, indicating that expression of luxS probably is not required for infectivity but, at the very least, is not essential for mammalian host adaptation. Our findings also challenge the notion that a LuxS/AI-2 quorum-sensing system is operative in B. burgdorferi. (+info)