Paraspinal desmoid fibromatosis after lumbar epidural analgesia.

A 14-year-old girl with cerebral palsy presented for bilateral lower limb surgery for spasticity. A lumbar epidural catheter was sited under general anaesthesia on the third attempt and used intra-operatively with good effect. A local anaesthetic infusion was used for postoperative analgesia but was noted to be leaking under the dressing with a patchy, unilateral block. The catheter was therefore removed on the second postoperative day. Following discharge, the patient progressively developed new back and leg pain for which she was re-admitted seven weeks later. This was investigated and initially thought to be myositis of the erector spinae muscles on magnetic resonance imaging. When the patient failed to respond to treatment, a muscle biopsy demonstrated desmoid fibromatosis. Trauma may cause or accelerate the development of desmoid fibromatosis, which has also been theorised to arise from scar tissue in previously injured areas. We hypothesise that challenging epidural placement or the leakage of the local anaesthetic agent into the surrounding muscular tissue, inducing local myonecrosis, could have been the triggering or accelerating event in tumour development. This may be the first reported case of extra-abdominal desmoid fibromatosis in association with epidural placement.

Monitoring the durability of long-lasting insecticidal nets in field conditions in Nepal.

Understanding and improving the durability of long-lasting insecticidal nets (LLINs) in the field is critical for the success of malaria prevention using mosquito nets, as well as contributing to procurement decisions based on the number of years of protection, rather than the current practice of unit cost. Using the recently published guidelines from the World Health Organization (WHO) some progress has been made in the monitoring and assessment of performance of nets in the field. This paper describes the protocol of an ongoing retrospective study of the attrition rate, physical integrity and bioefficacy of three polyester LLIN products that were distributed during 2010 to 2013 in Nepal. It is hoped that robust and auditable data on net survival (physical integrity and bioefficacy) of these three brands in different environments will assist the Nepal National Malaria Control Programme in planning future LLIN-replacement strategies, including behaviour-change communication about LLIN care and maintenance. The advantages and disadvantages of prospective and retrospective cross-sectional approaches are discussed, including appropriate strategies to validate the timing for mass distribution of nets. Similar studies should be done in other countries to (i) track LLIN durability to support management of resupply, and (ii) inform procurement decisions at the global level. New, more predictive, textile laboratory testing is also urgently needed.

An uncommon Essex-Lopresti fracture dislocation with radial displacement in distal direction: diagnosis and surgical treatment of a rare case.

Essex-Lopresti injuries are rare and present a clinical challenge. Incomplete diagnosis and treatment can lead to long-term instability, pain and functional impairment. We report on a clinical case of proximal radioulnar joint (PRUJ) and distal radioulnar joint (DRUJ) dislocation with unusual distal radial displacement and associated radial head shear fracture. The case was managed with closed reduction of the PRUJ and DRUJ followed by open reduction and fixation of the radial head. A high index of suspicion with thorough examination of the elbow, forearm and wrist and comprehensive imaging was important in reaching a complete diagnosis for appropriate treatment. Anatomical reduction of the PRUJ and DRUJ is essential to achieve optimal functional outcomes. Six months following the injury the patient made a satisfactory recovery with full range of movement; however, she continued to have mild to moderate general and moderate work-related disability.

Aedes aegypti disregard humidity-related conditions with adequate nutrition.

Weather variations have clear associations with the epidemiology of dengue fever and populations of Aedes aegypti mosquitoes. Data on humidity associations, however, lags with respect to its effect on host-biting, nectar-seeking and survival. This experimental study on Ae. aegypti, sourced from the arid tropics, investigated the effect of low and high relative humidity and diet in relation to host-biting, temporal variations in feeding frequency, and mosquito mortality. In each environmental setting, 10 replicates, containing one male and five female mosquitoes, were challenged with different nutritional sources every six hours over 12 days. Results showed that host-biting did not diminish in low humidity and was six times higher than expected. Sucrose feeding was observed to significantly moderate host-biting and water alone was inadequate for survival. The high host-biting rates help to explain the intensity of dengue epidemics, while the ability of the mosquito to disregard adverse humidity-related conditions helps to explain how dengue epidemics in arid tropical regions can be just as devastating as those in the wet tropics.

Aedes aegypti disregard humidity-related conditions with adequate nutrition

Weather variations have clear associations with the epidemiology of dengue fever and populations of Aedes aegypti mosquitoes. Data on humidity associations, however, lags with respect to its effect on host-biting, nectar-seeking and survival. This experimental study on Ae. aegypti, sourced from the arid tropics, investigated the effect of low and high relative humidity and diet in relation to host-biting, temporal variations in feeding frequency, and mosquito mortality. In each environmental setting, 10 replicates, containing one male and five female mosquitoes, were challenged with different nutritional sources every six hours over 12 days. Results showed that host-biting did not diminish in low humidity and was six times higher than expected. Sucrose feeding was observed to significantly moderate hostbiting and water alone was inadequate for survival. The high host-biting rates help to explain the intensity of dengue epidemics, while the ability of the mosquito to disregard adverse humidity-related conditions helps to explain how dengue epidemics in arid tropical regions can be just as devastating as those in the wet tropics.

Relationship between body composition, peripheral muscle strength and functional exercise capacity in patients with severe chronic obstructive pulmonary disease.

The influence of body composition and peripheral muscle strength on 6-minute walk distance was assessed by performing dual energy X-ray absorptiometry scanning, spirometry and dynamometry testing in 13 men and 13 women with severe chronic obstructive pulmonary disease. Multivariate modelling showed that 76% of the variance in 6-minute walk distance could be explained by an equation incorporating lung function, quadriceps strength and lean leg mass. These findings indicate an important role for lower limb strength measures in pulmonary rehabilitation training programmes.

Associations of peak shifts in age--prevalence for human malarias with bednet coverage.

Effects of bednet coverage (C) on prevalence of malaria were analysed using data from 1990-92 from 9 Papua New Guinean villages. Effects of coverage varied by age, resulting in a shift in age of peak prevalence from 4.7 (C = 0%) to 11.6 (C = 100%) years for Plasmodium falciparum, from 3.4 to 4.9 years for P. vivax and from 11.0 to 16.8 years for P. malariae. In small areas with no bednets the age distribution of P. falciparum parasitaemia was like that of a holoendemic area. Where coverage was complete the pattern corresponded to mesoendemicity. Thus, protracted use of bednets can result in profound changes in the endemicity of malaria even when coverage is incomplete and without insecticide treatment. Average entomological inoculation rates (EIRs) estimated from indoor landing rates on individuals without bednets were 35, 12 and 10 infectious bites per person per annum for P. falciparum, P. vivax and P. malariae, respectively. Logistic regression analyses indicated that the EIR estimate for P. falciparum was related to prevalence of this species independently of effects of bednet coverage. However, the recent EIR still accounted for much less variation than did the bednets. A similar pattern was seen for P. malariae, while there were no significant relationships between the recent EIR and the parasite positivity for P. vivax. It is concluded that short-term variations in inoculation rate are not important determinants of parasite prevalence in this population.

Area effects of bednet use in a malaria-endemic area in Papua New Guinea.

Relationships between area coverage with insecticide-free bednets and prevalence of Plasmodium falciparum were investigated in 7 community-based surveys over a 33-month period in 1990-93 in 6 villages in the Wosera area of Papua New Guinea. Spatial patterns in circumsporozoite rates for P. falciparum, P. vivax isomorphs K210 and K247, and P. malariae, and the proportions of mosquito blood meals positive for specific human, goat, cat, dog and pig antigens were determined using ELISAs. P. falciparum prevalence in humans was better explained by bednet coverage in the immediate vicinity than by personal protection alone. Circumsporozoite rates for both P. falciparum and P. vivax were also inversely related to coverage with bednets. There was some increase in zoophagy in areas with high coverage, but relatively little effect on the human blood index or on overall mosquito densities. In this setting, protracted use of untreated bednets apparently reduces sporozoite rates, and the associated effects on prevalence are greater than can be accounted for by personal protection. Even at high bednet coverage most anophelines feed on human hosts, so the decreased sporozoite rates are likely to be largely due to reduction of mosquito survival. This finding highlights the importance of local vector ecology for outcomes of bednet programmes and suggests that area effects of untreated bednets should be reassessed in other settings.

Comparison between anopheline mosquitoes (Diptera: Culicidae) caught using different methods in a malaria endemic area of Papua New Guinea.

The mosquito sampling efficiency of CDC (Centers for Disease Control) miniature light traps hung adjacent to mosquito nets, was compared with that of both indoor and outdoor human-bait collections in ten villages in the Wosera area of Papua New Guinea. The most frequently collected anopheline in the matched indoor and light trap samples was Anopheles koliensis Owen, followed by A. punctulatus Dönitz, A. karwari (James), A. farauti Laveran (sensu lato), A. longirostris Brug and A. bancroftii Giles. All species were much less frequent in the light traps than in landing catches. The hypothesis that the numbers of mosquitoes in light traps are proportional to human landing catches was examined using regression models that allowed for sampling error in both entomological measurements. Light traps under-sampled A. punctulatus and A. farauti s.l. at high densities. The models indicated that the ratio of light trap to landing catch females of A. koliensis and A. karwari increased with increasing mosquito density. Light trap catches of A. longirostris were proportional to indoor landing rates but when outdoor landing rates were high this species was under-sampled by light traps. Numbers of A. bancroftii in light traps were found to be proportional to those in outdoor landing catches, but were negatively related to those attempting to bite indoors. Circumsporozoite positivity rates for both Plasmodium falciparum Welch and P. vivax (Grassi & Feletti) in A. punctulatus and A. farauti s.l. were significantly higher in light trap collections than in either indoor or outdoor landing catches, suggesting that light traps may selectively sample older mosquitoes of these species.

The positive inotropic effects of milrinone but not of digoxin are attenuated at short cycle lengths.

The effects of inotropically active agents on the left ventricular force-interval relation are a potential determinant of their clinical utility and safety. However, little information is available concerning the effects of noncatecholamine positive inotropic agents on this relation. Therefore this study compared the short-term effects of digoxin and milrinone on resting hemodynamics, frequency potentiation (FP), and mechanical restitution (MR) in patients undergoing nonemergency cardiac catheterization. Both digoxin and milrinone produced similar increases in LV + dP/dt at rest (12.2 +/- 1.3%, p < 0.000001 and 11.4 +/- 3.2%, p < 0.01, respectively). The positive inotropic effects of digoxin were marginally attenuated during FP (by 8.5 +/- 4.2% and 4.6 +/- 2.9% at 10 and 60 s, respectively, both p = NS compared with baseline). Similarly, on MRC analysis, the parameter c (a measure of sensitivity of contractile performance to reductions in cycle length) increased by 3.6 +/- 3.7% (p = NS). Whereas the positive inotropic effects of milrinone were not significantly attenuated during FP, they were abolished and possibly reversed at short cycle lengths on MR curve construction (6.8 +/- 5.9% negative inotropic effect at 60% of resting cycle length; p = NS; p < 0.05 vs. resting cycle length). In conclusion, in patients with well-preserved left ventricular systolic function, the positive inotropic effects of milrinone but not of digoxin are markedly dependent on heart rate. These properties may influence both relative safety and efficacy of both agents.

The epidemiology and control of lymphatic filariasis on Lihir Island, New Ireland Province.

Clinical, parasitological and entomological surveys performed in 9 villages on Lihir Island, Papua New Guinea, before mass treatment with diethylcarbamazine (DEC), showed that lymphatic filariasis, caused by nocturnally periodic Wuchereria bancrofti, was endemic in 8 of them. Blood samples from 593 people revealed an overall microfilarial carrier rate of 24%. Amongst endemic villages, microfilarial carrier rates ranged from 5% to 43% and there was no significant difference in parasite prevalence between males and females. Obstructive filarial disease, defined as lymphoedema of the limbs or hydrocele, was observed in only 2% of 262 males examined. None of the 265 females examined had clinical symptoms. Entomological surveys yielded a total of 4095 mosquitoes including 3,692 anophelines and 241 culicines but only Anopheles farauti was found to harbour infective larvae of W. bancrofti. Pretreatment infection and infective rates of An. farauti were 7% and 1% respectively and up to 12 infective larvae were found in a single specimen. The microfilarial carrier rate in a cohort of people who received two DEC treatments dropped from 59% to 32% but the difference was not statistically significant. However, density of microfilaraemia decreased significantly from 170 to 10 mf/ml. Biannual mass treatment with DEC significantly reduced vector infection rates and transmission intensity on Lihir.

Mass treatment with ivermectin for filariasis control in Papua New Guinea: impact on mosquito survival.

Field studies were carried out to determine the impact of mass human treatment with ivermectin on the survival of anthropophagic mosquitoes of the Anopheles punctulatus complex (Diptera: Culicidae), the vectors of lymphatic filariasis and malaria in Papua New Guinea. In a village where mass treatment had been given, using 400 microg/kg ivermectin plus 6 mg/kg diethylcarbamazine citrate (DEC), we performed pre- and post-treatment collections of freshly blood-engorged mosquitoes from the same nine bedrooms. All blood-fed mosquitoes collected less than 4 days after mass treatment died within 9 days, whereas 67% of those collected before treatment survived for >9 days. Comparison (using the log-rank test) of the survival curves for mosquitoes collected (i) before treatment, (ii)<4 days after treatment, and (iii) 28 days after treatment, showed the survival rate of group (ii) to be significantly lower than the other two (chi2=176, df=2, P<0.0001). Pre- and post-treatment all-night landing catches showed no reduction in human biting rates in the experimental village. In another village, where people were mass treated with ivermectin (400 microg/kg) only, the survival rates of freshly blood-engorged An. punctulatus collected from bedroom resting-sites less than 1 day after treatment, were compared to similar collections carried out at the same time in a nearby village where people were not treated with ivermectin. The 48-h survival rate for the ivermectin-treated village was 31% compared to 94% for the other; this difference was highly significant (chi2=32.42, df=1, P<0.0001). Mosquitoes fed 2 months post-treatment with DEC or collected 38 days post-treatment with ivermectin had normal survival rates. We conclude that the duration of the systemic lethal effect of ivermectin on mosquitoes is insufficient to be of epidemiological significance in filariasis control programmes that are based on biannual and annual single-dose treatments, but might reduce vectorial capacity sufficiently to block epidemics of dengue or even malaria.

Effect of diet on biting, oviposition, and survival of Aedes aegypti (Diptera: Culicidae).

The effect of adult diet on host biting, sugar probing and water probing patterns, oviposition behavior, and survival of Aedes aegypti (L.) from Charters Towers, Australia, were tested in the laboratory. The 7 diets were as follows: (1) starvation, (2) water, (3) 10% sugar, (4) blood, (5) blood with water supplement, (6) blood with 10% sugar supplement, and (7) blood with 3% sugar supplement. Biting, probing, oviposition, and survival observations were made every 6 h (0600-0800 hours, 1200-1400 hours, 1800-2000 hours, 2400-0200 hours). Biting frequency on the blood with 3% sugar diet (0.26 feeds per mosquito per 6 h) and the blood with 10% sugar diet (0.23 feeds per mosquito per 6 h) was significantly less than on blood (0.51 feeds per mosquito per 6 h) and 10% sugar (0.40 feeds per mosquito per 6 h) alone. Biting frequency was not significantly different between blood with water (0.47 feeds per mosquito per 6 h) and blood alone (0.51 feeds per mosquito per 6 h). Biting and oviposition occurred throughout the day, peaking between 1800 and 2000 hours and between 2000 and 2400 hours, respectively. Biting frequency with a 3% sugar supplement decreased after the 1st oviposition cycle on day 6 compared with unsupplemented biting. The presence of sugar delayed or inhibited oviposition. Females with access to blood with water bit and oviposited concurrently on days 4-6, 8-9, and 11, indicating a 3-d gonotrophic cycle. Survival on blood alone was not significantly lower than survival on sugar and water supplemented diets. Behavior of the Charters Towers strain proved to be significantly influenced by diet, and biting occurred opportunistically without regard for previously observed crepuscular or diurnal rhythms. The biting frequencies observed were the highest yet recorded for this species, which indicates that the vectorial capacity of the Australian Ae. aegypti may be underestimated severely.

Adaptation of Aedes aegypti (Diptera: Culicidae) oviposition behavior in response to humidity and diet.

Effects of humidity and sugar concentration on the fecundity, temporal oviposition patterns and survival of a tropical strain of Aedes aegypti (L.) were investigated. Fecundity was significantly reduced by low humidity, but was not affected by sugar concentration. Low humidity caused a significant decrease in percentage survival after 19 days as compared to high humidity. Oviposition was inhibited by host availability for eight successive days. When access to a host was no longer provided, oviposition continued for 10 days in three to four distinct cycles without additional bloodmeals. Humidity stress and high sugar concentration caused oviposition to be delayed for one to four days, which is the typical duration of extreme low humidity periods in nature. These responses are hypothesized to protect the eggs of ovipositing females against the environmental hardships of periodic humidity stress and lack of hosts, thus enabling the perpetuation of the vector and the diseases it transmits in hot and dry seasons.

Application of multiplex PCR for detection of non-O157 verocytotoxin-producing Escherichia coli in bloody stools: identification of serogroups O26 and O111.

Primers were designed to amplify sequences of verocytotoxin genes and eaeA genes of Escherichia coli O26:H11, O111:H8, and O157:H7 in a multiplex PCR assay. This assay successfully detected E. coli O26:H11 in bloody stool specimens in which other enteric pathogens were not detected by culture-based methods. Rapid assays to detect non-O157:H7 verocytotoxin-producing E. coli is important to improve methods for the etiologic diagnosis of hemorrhagic colitis.

Diagnosis of Plasmodium falciparum infection using ParaSight(R)-F test in blood and urine of Papua New Guinean children.

Rapid, simple, accurate and cheap methods are required for the diagnosis of malaria in endemic areas. The ParaSight(R)-F test, which is based on qualitative detection by monoclonal antibody of the Plasmodium falciparum (Pf) histidin-rich protein-II in the blood, showed promising results. As some antigens of Pf have been detected in the urine, we assessed the efficiency of the ParaSight(R)-F test in the whole blood and in the urine using microscopy and PCR as gold standards. One hundred and twelve children living in the East Sepik Province of Papua New Guinea (PNG) were recruited during a cross-sectional community survey. When using microscopy as reference, the ParaSight(R)-F test applied to whole blood had 84% sensitivity and 77% specificity. The semi-quantitative assessment showed that the intensity of the color on the wick correlated with parasite density. The ParaSight(R)-F test performed on urine had 81% sensitivity but only 26% specificity. Very similar results for blood and urine were obtained when using PCR as reference. The present evaluation of the ParaSight(R)-F test applied to blood compares well with findings in endemic areas of Africa or Asia, and confirms its usefulness to diagnose Pf infection in endemic areas of the South Pacific. Because of the lack of specificity, the ParaSight(R)-F test performed on urine cannot be recommended.

Multiple host-feeding and biting persistence of Aedes aegypti.

The effects of host activity, host defensive behaviour and biting persistence on multiple host-feeding by Aedes aegypti (L.) were investigated, in laboratory conditions, on human volunteers. In four different settings, four or five volunteer hosts displayed inactive, mildly active, mildly defensive and highly defensive behaviour. Into each of the four trials, each with 20 replicates, a single mosquito was released for a period of 10 min. In all settings, the median number of hosts sought per mosquito was constant, regardless of host activity and host defensive behaviour. Host defensive behaviour was thus not seen to exert a selective pressure on mosquitoes to abandon their hosts. No relationship was found between biting persistence and the number of hosts sought, indicating that biting persistence does not affect disease transmission. As one of the female hosts was consistently and significantly less attractive to host-seeking mosquitoes than any other volunteer in all four settings, it seems that some individuals are significantly less at risk from mosquito-borne pathogens than others.

Short-term myocardial uptake of d- and l-sotalol in humans: relation to hemodynamic and electrophysiologic effects.

The myocardial concentration of many cardioactive drugs has been identified as an important determinant of their short-term effects in previous studies. Although sotalol is frequently administered via short-term intravenous injection, no previous studies had sought to correlate its uptake by the heart with its various effects. We determined the time course of short-term uptake of d,l-sotalol by human myocardium in vivo and investigated the relation between myocardial content of sotalol and the short-term hemodynamic, electrocardiographic, and electrophysiologic effects of the drug. Sixteen patients received a 20-mg intravenous bolus of sotalol at the time of diagnostic cardiac catheterization. Myocardial content of d- and l-sotalol (by using a paired transcoronary sampling technique) and the short-term hemodynamic and electrophysiologic effects of the drug were determined < or = 20 min after injection. Myocardial accumulation of sotalol was not enantioselective, proceeded very rapidly (maximal at 0.74 +/- 0.10 min, representing 2.05 +/- 0.45% of the total injected dose), and was not significantly influenced by left ventricular systolic function or the extent of coronary artery disease. Approximately one third of peak myocardial content was still present 17.5 min after sotalol administration. Maximal effects of the drug (reduction in spontaneous heart rate, p < 0.005; reduction in maximal rate of LV pressure increase (LV+dP/dtmax, p < 0.005); and prolongation of PR intervals, p < 0.02) were delayed by approximately 10 min relative to maximal myocardial sotalol content. The significant prolongation of AH intervals (p < 0.01) and atrioventricular nodal effective refractory periods (p < 0.0002) that was observed was also maximal 10 min after administration of sotalol. Thus a consistent delay between myocardial sotalol content and the short-term effects of the drug was observed. In conclusion, the accumulation of both d- and l-sotalol by the human myocardium is more rapid than that of any other agent studied to date, with considerable hysteresis between myocardial drug uptake and subsequent cardiac effects.

Relationship between myocardial milrinone content and its acute hemodynamic and electrophysiologic effects.

One of the major determinants of the short-term effects of many cardioactive drugs is the concentration of the drug specifically within the myocardium. However, no information regarding the disposition of the phosphodiesterase inhibitor milrinone in the heart is available. We therefore determined the time course of short-term myocardial milrinone uptake from paired transcoronary sampling and simultaneous coronary sinus blood flow after a 1-mg intravenous bolus in patients undergoing diagnostic cardiac catheterization. In accordance with this intention, a sensitive, reproducible method for the determination of milrinone in human whole-blood samples was developed. The reverse-phase high-performance liquid chromatographic method described used a C18 column with UV-absorbance detection at 326 nm, with a limit of detection of 0.6 ng/ml, and was highly reproducible. The short-term hemodynamic and electrophysiologic effects of the drug also were determined. Significant increases in spontaneous heart rate and LV+dP/dtmax (at constant heart rate) were observed, accompanied by reductions in mean arterial pressure, systemic vascular resistance, and PR interval, without significant changes in atrioventricular nodal or ventricular effective refractory periods. Peak content (1.89 +/- 0.30% of injected dose) was rapidly attained, 0.56 +/- 0.06 min after milrinone injection. Time of peak effects was significantly delayed (7-10 min after injection) relative to time of peak myocardial milrinone content. Residual myocardial milrinone content was 69.1 +/- 5.7% of maximum 12.5 min after injection. It is concluded that both myocardial uptake and the onset of positive inotropic effects after intravenous injection of milrinone were very rapid. However, there was significant hysteresis between peak myocardial content and subsequent hemodynamic effects.

Antiarrhythmic drug effects on QT interval dispersion in patients undergoing electropharmacologic testing for ventricular tachycardia and fibrillation.

The effects of antiarrhythmic drugs on QT interval dispersion as a predictor of antiarrhythmic drug therapy has not been rigorously assessed. This study was performed to determine whether the effects of antiarrhythmic drugs on QT interval dispersion predict antiarrhythmic drug response in patients undergoing electropharmacologic testing for ventricular tachycardiarrythmias. Precordial QT intervals and QT interval dispersions were measured at baseline and during steady-state antiarrhythmic drug therapy in 72 consecutive patients with documented coronary artery disease and remote myocardial infarction presenting with spontaneous sustained ventricular tachyarrhythmias who underwent electropharmacologic studies to assess arrhythmia suppression. QT interval dispersion was similar at baseline in drug responders (42 +/- 21 ms) and drug nonresponders (46 +/- 21 ms), whereas during antiarrhythmic therapy QT interval dispersion was shorter in drug responders (33 +/- 15 ms) than in drug nonresponders (55 +/- 29 ms, p <0.001). QT interval dispersion was shorter in 7 drug responders during their effective drug trials (27 +/- 14 ms) than during their ineffective drug trials (47 +/- 24 ms, n = 9, p <0.05). QT dispersion < or = 50 ms (p <0.002) and a patent infarct-related artery (p <0.003) were independent predictors of antiarrhythmic therapy. The positive and negative predictive value of QT interval dispersion during drug therapy to predict a successful drug response was 32% and 96%, respectively. QT interval dispersion predicted the outcome of electropharmacologic studies independent of infarct-related artery patency. QT interval dispersion >50 ms during drug therapy was associated with ineffective drug therapy.