Strongyloidiasis: a review of the evidence for Australian practitioners

OBJECTIVE: To summarise the available evidence concerning the prevalence, clinical manifestations, diagnosis and management of strongyloidiasis in Northern Australia. METHODS: We searched Medline, Clinical Evidence and the Cochrane Library using MeSH terms and text words 'strongyloides OR strongyloidiasis'. For Australian studies we included text words '(parasite* OR parasitic OR helminth*) AND Australia*'. We examined references contained in retrieved studies or identified from direct contact with researchers. Studies consistent with our objective that described their methods were eligible for inclusion. RESULTS: The prevalence in some tropical Aboriginal communities is high. Infection can be asymptomatic, cause a range of clinical syndromes or death. It may become chronic. Infected patients are at risk of developing severe disseminated disease particularly with immune compromise. There is little information about the relative frequency of different clinical outcomes. Available diagnostic tools are imperfect. Stool examination has a low sensitivity. Serology may have a low specificity in high prevalence populations and has not been evaluated in Aboriginal populations. Antihelmintic drugs are relatively safe and effective. Community programs based on treatment of stool-positive cases have been associated with a reduced prevalence of strongyloidiasis. We found no studies examining alternative public health interventions. CONCLUSION: There is a high prevalence in many Aboriginal communities. Strongyloides infection should be excluded prior to commencing immunosuppressive therapies in patients from endemic areas. Further studies examining the public health impact of strongyloidiasis, the role of the enzyme-linked immuno-sorbent assay serological test and population-based approaches to management of the disease in endemically infected Australian populations are needed.     

Asymptomatic total hip prosthesis: natural history determined using Tc- 99m MDP bone scans

A prospective study was performed with 97 patients who had undergone total hip replacement surgery and who were not experiencing pain or other symptoms or problems. The study was intended to determine the normal postoperative appearance of radionuclide scans of the hip following administration of technetium-99m methylene diphosphonate. Five areas of the prostheses were evaluated. Results showed that 6 months after implantation activity around the lesser trochanter and prosthesis shaft became insignificant. Activity around the acetabulum, greater trochanter, and prosthesis tip stabilized approximately 2 years after surgery; approximately 10% of patients in the study had persistent activity in these areas. Familiarity with this normal progression is fundamental to interpretation of postoperative bone scans in patients with total hip prosthesis.     

Crystalloid or colloid for partial exchange transfusion in neonatal polycythemia: a systematic review and meta-analysis

AIMS: To determine whether crystalloid solutions are as effective as colloid solutions when a partial exchange transfusion is performed in newborns with polycythemia. METHODS: We searched MEDLINE, EMBASE, and the Cochrane Controlled Trials Register of the Cochrane Library (1966-2004). Keywords used were: polycythemia, partial exchange transfusion, hyperviscosity, and limited to newborn. Randomized studies in newborns with polycythemia were selected for evaluation. Outcomes examined were: long-term neurodevelopment; short-term physiological effects; improvement in clinical symptoms; reduction in haematocrit at 4-6 h; haematocrit at 24 h; and frequency of serious complications. RESULTS: Four randomized controlled clinical trials, including 200 patients in total, with evaluable data, which satisfied our criteria, were found. There were no data on long-term outcomes. There is no reported important difference in short-term physiologic effects. Use of crystalloid was as effective as colloid in both correction of haematological values and reduction of clinical symptoms following partial exchange transfusion.CONCLUSION: Crystalloid solutions are as effective as colloid solutions for partial exchange transfusion. When crystalloid solutions are used for this purpose, there is no risk of transmission of blood-borne diseases, there is no risk of anaphylaxis, they are rapidly and easily available, and are less expensive. The use of crystalloid should become the standard for partial exchange transfusion.     

Lack of response to epidermal growth factor in adult neural progenitor cells

Neural progenitor/stem cells reside in the subventricular zone and dentate gyrus of the adult rat brain, which proliferate in response to several growth factors. Here we show that the neurospheres generated from the adult dentate gyrus and subventricular zone proliferate in vitro in response to fibroblast growth factor-2, but not epidermal growth factor. Likewise, extracellular signal-regulated kinase phosphorylation was stimulated by fibroblast growth factor-2, but not epidermal growth factor. Immunoblotting demonstrated negligible epidermal growth factor receptor content in these neurospheres, indicating that neural progenitor cells isolated from the adult rat brain are not responsive to epidermal growth factor in vitro, because of the lack of epidermal growth factor receptors and/or their signaling. However, the lack of response by epidermal growth factor in our study could be because of the culture conditions, and may not reflect the physiological condition.     

In vivo testing of an infection-resistant annuloplasty ring

BACKGROUND: An infection-resistant surface incorporated into a prosthetic cardiac valve has great potential clinical applications. STUDY DESIGN: A sewing ring construct was created using ciprofloxacin-treated polyester. Then ciprofloxacin-treated and untreated constructs were implanted subcutaneously on the dorsum of rats and inoculated with Staphylococcus aureus. At 7, 14, and 30 days animals were sacrificed and the implants were retrieved. Each implant was assessed for frank purulence and gross tissue incorporation by a blinded observer. The implants were processed for conventional histology and examined by a blinded Pathologist. Ciprofloxacin-treated rings were also implanted in the absence of a bacterial challenge. At explantation, a maximal zone of inhibition, if present, was measured. Finally, ciprofloxacin was eluted with methanol from the explanted segments and the concentration of ciprofloxacin eluted was determined. RESULTS: Ciprofloxacin-treated sewing rings had greater gross tissue incorporation than untreated rings in the presence of a bacterial challenge (P=0.005). Ciprofloxacin-treated rings also had a lower incidence of frank purulence, but this did not reach statistical significance. After 14 days of implantation, ciprofloxacin treated rings had fewer neutrophils (P=0.018) and greater histological tissue incorporation (P=0.017) than untreated rings. The explanted ciprofloxacin-treated rings maintained a zone of inhibition of 3.0+/-1.0 mm after 1 day of implantation and 1.3+/-0.6 mm after 2 days. Ciprofloxacin could be eluted in significant quantities from the explanted rings after 7 days of implantation. CONCLUSIONS: Ciprofloxacin treated polyester can be incorporated into an annuloplasty ring construct that demonstrates excellent tissue incorporation and infection resistance. This study supports the use of this construct in the mitral position in a large animal model.     

Effects of exercise-induced arterial hypoxaemia on limb muscle fatigue and performance

1. Reductions in arterial O(2) saturation (-5% to -10%S(a)o(2) below rest) occur over time during sustained heavy-intensity exercise in a normoxic environment, caused primarily by the effects of acid pH and increased temperature on the position of the HbO(2) dissociation curve. 2. We prevented the desaturation incurred during exercise at approximately 90% VO(2 MAX) via increased fraction of inspired O(2) (F(i)o(2)) (0.23 to 0.29) and showed that exercise time to exhaustion was increased. 3. We used supramaximal magnetic stimulation (1-100 Hz) of the femoral nerve to test for quadriceps fatigue. We used mildly hyperoxic inspirates (F(i)o(2) 0.23 to 0.29) to prevent O(2) desaturation. We then compared the amount of quadriceps fatigue incurred following cycling exercise at S(a)o(2) 91% vs 98% with each trial carried out at identical work rates and for equal durations. 4. Preventing the normal exercise-induced O(2) desaturation prevented about one-half the amount of exercise-induced quadriceps fatigue; plasma lactate and effort perception were also reduced. In a subset of less fit subjects who showed only minimal arterial hypoxaemia during sustained exercise (S(a)o(2) approximately 95%), breathing a mildly hypoxic inspirate (F(i)o(2) 0.17; S(a)o(2) approximately 88%) exacerbated the quadriceps fatigue. 5. We conclude that the normal exercise-induced O(2) desaturation during heavy-intensity endurance exercise contributes significantly to exercise performance limitation in part because of its effect on locomotor muscle fatigue.