Body rate decoupling using haltere mid-stroke measurements for inertial flight stabilization in Diptera.

Halteres, the modified rear wings of Diptera, have long been recognized as sensory organs necessary for basic flight stability. These organs, which act as vibrating structure gyroscopes, are known to sense strains proportional to Coriolis accelerations. While compensatory responses have been demonstrated that indicate the ability of insects to distinguish all components of the body rate vector, the specific mechanism by which the halteres are able to decouple the body rates has not been clearly understood. The research documented in this report describes a potential mechanism, using averaged strain and strain rate at the center of the haltere stroke, to decouple the inertial rate components. Through dynamic simulation of a nonlinear model of the haltere 3-dimensional trajectory, this straightforward method was demonstrated to provide an accurate means of generating signals that are proportional to three orthogonal body rate components. Errors associated with residual nonlinearity and rate-coupling were quantified for a bilaterally reconstructed body rate vector over a full range of pitch and yaw rates and two roll rate conditions. Models that are compatible with insect physiology are proposed for performing necessary signal averaging and bilateral processing.

Intra-venous albumin for preventing severe ovarian hyperstimulation syndrome.

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic condition that occurs after the administration of human menopausal gonadotrophin (hMG) with or without gonadotrophin releasing hormone (GnRH) agonists. OHSS is a threat to every woman undergoing ovulation induction and is potentially lethal in its severest form. Severe OHSS is characterised by growth of multiple large follicles with massive extravascular protein rich fluid shift. This may lead to hypovolaemia, haemoconcentration, oliguria, and electrolyte disturbance. Human albumin solutions are now used in the management of shock and other conditions in which restoration of blood volume is urgent, the acute management of burns, and clinical situations associated with hypoproteinaemia. Recently, a number of clinical trials with conflicting results have been reported in which albumin has been tested as a possible way for preventing the severe form of OHSS. OBJECTIVES: To review the effectiveness of human albumin administration in prevention of severe ovarian hyperstimulation syndrome. SEARCH STRATEGY: The Menstrual Disorders and Subfertility Group literature search strategy was used to identify randomised trials that had compared the use of human albumin with placebo or no treatment in the prevention of severe ovarian hyperstimulation syndrome. A diverse search strategy was employed, including handsearching of core journals from 1966 to the present, searching bibliographies of relevant trials, MEDLINE, EMBASE, PsychLIT and CINAHL databases, the MDSG specialised register, abstracts from North American and European meetings and contact with authors of relevant papers. SELECTION CRITERIA: Trials were included if they compared the effect of human albumin with placebo or no treatment on relevant outcomes. Only randomised controlled studies were included in this review. DATA COLLECTION AND ANALYSIS: Trials under consideration were evaluated for methodological quality and appropriateness for inclusion without consideration of their results. Relevant data were extracted independently by two reviewers using the standardized data extraction sheet. Validity was assessed in terms of method of randomization, completeness of follow-up, presence or absence of crossover and co-intervention. DATA SYNTHESIS: 2x2 tables were generated for all relevant outcomes. Odds ratios were calculated using the Peto modified Mantel-Haenszel technique. MAIN RESULTS: Meta-analysis of the three included trials demonstrated significant reduction in severe ovarian hyperstimulation syndrome on administration of human albumin (common odds ratio 0.1, 95% confidence interval 0.03 to 0.39). There was no evidence of an increase in the pregnancy rate (common odds ratio 1.69, 95% confidence interval 0.7 to 4.07). REVIEWER'S CONCLUSIONS: This review shows a clear benefit from administration of intra-venous albumin at the time of oocyte retrieval in prevention of severe OHSS in high-risk cases. However, the results of this review can not be regarded as conclusive as they are based on only three small trials. Further trials are urgently needed.

Intra-venous albumin for preventing severe ovarian hyperstimulation syndrome.

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic condition that occurs after the administration of human menopausal gonadotrophin (hMG) with or without gonadotrophin releasing hormone (GnRH) agonists. OHSS is a threat to every woman undergoing ovulation induction and is potentially lethal in its severest form. Severe OHSS is characterised by growth of multiple large follicles with massive extravascular protein rich fluid shift. This may lead to hypovolaemia, haemoconcentration, oliguria, and electrolyte disturbance. Human albumin solutions are now used in the management of shock and other conditions in which restoration of blood volume is urgent, the acute management of burns, and clinical situations associated with hypoproteinaemia. Recently, a number of clinical trials with conflicting results have been reported in which albumin has been tested as a possible way for preventing the severe form of OHSS. OBJECTIVES: To review the effectiveness of human albumin administration in prevention of severe ovarian hyperstimulation syndrome. SEARCH STRATEGY: The Menstrual Disorders and Subfertility Group literature search strategy was used to identify randomised trials that had compared the use of human albumin with placebo or no treatment in the prevention of severe ovarian hyperstimulation syndrome. A diverse search strategy was employed, including handsearching of core journals from 1966 to November 2001, searching bibliographies of relevant trials, MEDLINE, EMBASE, PsychLIT and CINAHL databases, the MDSG specialised register, abstracts from North American and European meetings and contact with authors of relevant papers. SELECTION CRITERIA: Trials were included if they compared the effect of human albumin with placebo or no treatment on relevant outcomes. Only randomised controlled studies were included in this review. DATA COLLECTION AND ANALYSIS: Seven randomised controlled trials were identified, five of which met our inclusion criteria and enrolled 378 women (193 in the albumin treated group and 185 in the control group). Trials under consideration were evaluated for methodological quality and appropriateness for inclusion without consideration of their results.The five included trials were single-centre parallel randomised controlled studies. Relevant data were extracted independently by two reviewers using the standardized data extraction sheet. Validity was assessed in terms of method of randomisation, completeness of follow-up, presence or absence of crossover and co-intervention. DATA SYNTHESIS: 2x2 tables were generated for all relevant outcomes. Odds ratios were calculated using the Peto modified Mantel-Haenszel technique. MAIN RESULTS: Meta-analysis of the five included trials demonstrated significant reduction in severe ovarian hyperstimulation syndrome on administration of human albumin (odds ratio was 0.28 (95% CI 0.11 to 0.73). Relative risk was 0.35 (0.14 - 0.87) and absolute risk reduction was 5.5. For every 18 women at risk of severe OHSS, albumin infusion will save one more case. There was no evidence of an increase in the pregnancy rate (odds ratio was 1.09, (95% CI 0.65 to 1.83) REVIEWER'S CONCLUSIONS: This review shows a clear benefit from administration of intra-venous albumin at the time of oocyte retrieval in prevention of severe OHSS in high-risk cases. Whether the NNT would justify the routine use of albumin infusion in cases at risk of severe OHSS needs to be judged by clinical decision makers.

Intravenous albumin for preventing severe ovarian hyperstimulation syndrome: a Cochrane review.

BACKGROUND: The effectiveness of human albumin administration in prevention of severe ovarian hyperstimulation syndrome (OHSS) was reviewed using the Cochrane Menstrual Disorders and Subfertility Group literature search strategy. METHODS: Only randomized controlled trials (RCT) comparing the effect of human albumin with placebo or no treatment were included in this review. Seven RCT were identified, five of which met our inclusion criteria and enrolled 378 women (193 in the albumin-treated group and 185 in the control group). Trials under consideration were evaluated for methodological quality and appropriateness for inclusion without consideration of their results. The five included trials were single-centre parallel RCT. Relevant data were extracted independently by two reviewers using the standardized data extraction sheet. Validity was assessed in terms of method of randomization, completeness of follow-up, presence or absence of crossover and co-intervention. RESULTS: There was significant reduction in severe OHSS on administration of human albumin [odds ratio (OR): 0.28; 95% confidence interval (95% CI) 0.11-0.73]. Relative risk was 0.35 (95% CI 0.14-0.87) and absolute risk reduction was 5.5. For every 18 women at risk of severe OHSS, albumin infusion will save one more case. There was no evidence of an increase in the pregnancy rate [OR 1.09 (95% CI 0.65-1.83)]. CONCLUSIONS: This Cochrane review shows a clear benefit from administration of i.v. albumin at the time of oocyte retrieval in prevention of severe OHSS in high-risk cases. Whether the number needed to treat would justify the routine use of albumin infusion in cases at risk of severe OHSS needs to be judged by clinical decision-makers.

Comparison of parametrized models for computer-based estimation of diabetic patient glucose response.

Two mathematical models for the description of diabetic patient glucose behaviour are proposed. Unlike high order differential-equation based compartmental models, these models employ only the data typically available to a diabetic patient: the history of measured blood glucose concentrations and of insulin injections. The model structures are compared with a native benchmark (zero-order hold) model in a computer simulation. It is demonstrated that, given four daily blood glucose measurements and two daily insulin injections, a parametrized model of patient blood glucose response to insulin can provide relevant data in the estimation of a patient's future blood glucose response in terms of past blood glucose measurements and insulin injections. Parametrized model root means squared errors of glycaemic predictions for 18 simulated patients ranged from 7-22 mg dl-1, as compared with 19-42 mg dl-1 for the benchmark model.