Cost and effectiveness comparison of two methods for screening potential blood donors for anaemia in Vietnam.

AIM/OBJECTIVE: To compare the cost and effectiveness of Copper Sulphate (CS) and HemoCue (HC) methods for screening blood donors for anaemia. BACKGROUND: Robust information from developing countries about cost and effectiveness of anaemia screening methods for blood donors is scarce. In such countries there are widespread shortages of blood, so the most cost-effective method should maximise blood supply without compromising donor safety. METHODS: Economic data (e.g. staff time, equipment and buildings) were collected from direct observation of procedures and purchase data from Hanoi's Central Blood Bank administrative department. A framework for comparing the cost and effectiveness of anaemia screening methods was developed and a cost per effective (i.e. usable and accurate) test was generated for each method. RESULTS: Samples from 100 potential donors from the Hanoi Central Blood Bank (static) and 198 from two mobile units were tested. The mean probability of an ineffective anaemia test was 0·1 (0·05-0·2). The average cost of an HC test was $0·75 (static $0·61 and mobile $0·89) and a CS test was $0·31 (static $0·17 and mobile $0·45). The difference between static and mobile units was predominantly due to transport costs; the difference between the two methods was predominantly due to the HC microcuvettes. CONCLUSION: In this setting the CS yields greater value for money than the HC method for screening blood donors. The relative cost and effectiveness of CS and HC may be different in places with higher staff turnover, lower test accuracy, higher anaemia prevalence or lower workload than in Vietnam.

Sialivac: an intranasal homologous inactivated split virus vaccine containing bacterial sialidase for the control of avian influenza in poultry.

A simple, effective inactivated avian flu vaccine composed of three homologous highly pathogenic (HP) H5N1 strains combined with Clostridium perfringens type A 107 sialidase/neuramindase and chitosan as a trans epithelial carrier adjuvant applied intranasally to poultry is described. Poultry were vaccinated with an inactivated, solvent split, chitosan adjuvanted intranasal (IN) vaccine with and without C. perfringens sialidase and the resulting serum IgG antibody measured by haemagglutination inhibition (HI) and mucosal IgA by ELISA. The clinical effectiveness was demonstrated by disease intervention field trials, where the ability of an intranasal vaccine containing three homologous inactivated solvent split HP H5N1 strains, C. perfringens sialidase and chitosan was successful in controlling the disease in intensively reared commercial chickens. Evidence is presented by demonstrating effective intervention with IN vaccine during outbreaks in poultry previously vaccinated with commercial heterologous H5N2 intramuscular (IM) vaccine and reassorted H5N1 Re-1 vaccine which had failed to protect intensively reared birds. Intervention with the IN vaccine in such flocks completely halted the infection within 2-5 days. Survivors ceased to excrete live virus. Stimulation of the common mucosal immune system (CMIS) and the early production of secretory IgA and subsequently humoral IgG demonstrated by laboratory controlled experiments and field studies revealed the ability of intranasally vaccinated birds to resist lethal virus challenge. A strategy of mucosal immunisation is recommended to reduce the incidence of disease in intensively reared poultry and thus minimise the generation and transfer of mutated highly pathogenic subtypes to humans and other animals.

A model to simulate the impact of timing, coverage and transmission intensity on the effectiveness of indoor residual spraying (IRS) for malaria control.

OBJECTIVE: (i) To develop a temperature- and rainfall-driven model of malaria transmission capable of prediction. (ii) To use the model to examine the relationship between the intervention timing and transmission intensity on the effectiveness of indoor residual spraying (IRS). METHODS: A dynamic model of malaria transmission was developed from existing models of malaria transmission dynamics. The model was used to retrospectively predict actual malaria cases from Hwange district in Zimbabwe using actual meteorological and IRS timing and coverage data. Simulations of alternative intervention scenarios (timing and coverage) examined the effectiveness of earlier and later interventions, at higher and lower coverage levels in epidemic and non-epidemic years. FINDINGS: The model was able to predict actual malaria cases in Hwange over a four-and-a-half-year period with a lead time of 4 months (e.g. January rainfall and temperature predicts April malaria) and a correlation coefficient of 0.825 (r(2) = 0.6814). The IRS simulations show that the marginal benefits of increasing IRS coverage are higher in high-transmission (HT) years relative to lower transmission years. This implies that over a period of years, maximum impact could be achieved with a given quantity of insecticide by increasing coverage in HT years. However, the model also shows that earlier spraying is more effective in all years, especially so in epidemic years, and that IRS has limited impact if it is carried out too late in relation to peak transmission. CONCLUSION: Temperature- and rainfall-driven models of malaria transmission have the potential to predict malaria epidemics. Early intervention based on prior knowledge of the magnitude of the malaria season can be more effective and efficient than carrying out routine activities every year. Malaria control planners need improved access to the technology that would allow them to better predict malaria epidemics and develop Malaria Early Warning Systems (MEWS). MEWS can then be linked to intervention planning to reduce the devastating impact of malaria epidemics on populations.

Xerovac: an ultra rapid method for the dehydration and preservation of live attenuated Rinderpest and Peste des Petits ruminants vaccines.

The accepted procedure for the long-term preservation of live viruses and bacteria in vaccines has been lyophilisation. We show that thermolabile viruses can be dehydrated in vitro, within 18 h, in an excipient containing trehalose. We further demonstrate that in the resulting dehydrated state, where the viruses are captive in a metastable glass composed of trehalose, they are capable of resisting 45 degrees C for a period of 14 days with minimal loss of potency. The degree of thermotolerance achieved matches that of current 'thermostable' lyophilised vaccines, but with the distinct advantage of a shorter, cheaper and simpler process. The development and utilisation of this process can make significant improvements in current live virus vaccine production. It presents a further step away from dependence on mandatory low temperature refrigerated storage and could lead to greater confidence in vaccine stability, potency and efficacy.

Hepatic carbon flux after re-feeding in the glycogen-storage-disease (gsd/gsd) rat.

In this study we utilized the phosphorylase b kinase-deficient (gsd/gsd) rat as a model of hepatic substrate utilization where there is a constraint on glycogenesis imposed by the maintenance of high glycogen concentrations. Glucose re-feeding of 48 h-starved gsd/gsd rats led to suppression of hepatic glucose output. In contrast with the situation in normal rats, activation of the pyruvate dehydrogenase complex and lipogenesis was observed. It is suggested that impeding glycogenic flux may divert substrate into lipogenesis, possibly via activation of the pyruvate dehydrogenase complex.

3-Hydroxyisobutyrate dehydrogenase, an impurity in commercial 3-hydroxybutyrate dehydrogenase.

The enzymic determination of D-3-hydroxybutyrate and acetoacetate normally involves the use of 3-hydroxybutyrate dehydrogenase (HBDH, EC 1.1.1.30) of bacterial origin. We show that HBDH from Rhodopseudomonas spheroides (BCL, grade II) contains a 3-hydroxyisobutyrate dehydrogenase (HIBDH) activity: activity with 3-hydroxyisobutyrate as substrate was greater than 10% of that with 3-hydroxybutyrate. However, HBDH could be prepared essentially free of HIBDH activity by incubation at 37 degrees C in the presence of 1 mM-CaCl2, to produce an enzyme preparation that may be used for the specific determination of 3-hydroxybutyrate. Use of the purified enzyme preparations indicated that a major product of valine metabolism in hemidiaphragms from 40 h-starved rats was 3-hydroxyisobutyrate rather than 3-hydroxybutyrate.

Bluetongue in western Turkey.

In October 1977 clinical bluetongue broke out in Aydin province, western Turkey and spread to adjacent provinces in the autumn months of 1978 and 1979. The outbreak was caused by a virus of serotype 4 and appeared to occur in a totally susceptible population. It was eventually controlled by widespread use of attenuated type-specific vaccine. Bluetongue virus was isolated from sheep on several occasions and also from a calf with congenital arthrogryposis and hydranencephaly. This latter finding is discussed in relation to Akabane virus, a recognised arbovirus teratogen thought to be present in the same area at the same time.

Controlled studies of the acute antidepressant effects of lithium.

In two randomized double-blind controlled trials on 63 depressed female in-patients subject to recurrent affective disorder (bipolar and unipolar manic-depressive psychosis) lithium was shown to have major acute antidepressant effects. At the end of three weeks lithium produced more uniform improvement than did imipramine; lithium in combination with tryptophan (in the form of Optimax) was superior to tryptophan alone--the latter drug having no discernible antidepressant activity in this group of patients. Lithium did not produce an antidepressant effect until the second and third week of both trials.

Cognitive functions in manic-depressives: effects of lithium and physostigmine.

Cognitive functions were investigated in seven manic depressive patients while on lithium, after two weeks off lithium, and after a subcutaneous injection of physostigmine while on lithium. Test performance was unaffected by lithium, but after physostigmine the I.Q. score of a shortened version of the WAIS was significantly increased.

Changes in the erythrocyte sodium pump with age.

Various estimations of the erythrocyte sodium pump were determined in 18 female and 11 male adult subjects. In the female group, but not in the male group, the sodium concentration increased with age; the erythrocyte active transport decreased and passive transport increased with age and could account for the observed change in erythrocyte sodium concentration with age. The erythrocyte Na-K ATPase decreased with age in the females and this could account for the observed change in active transport.

Erythrocyte membrane cation carrier in mania.

Erythrocyte sodium and potassium concentrations, erythrocyte membrane ATPase (Na-K specific and non-specific) and the rate of potassium influx into erythrocytes (ouabain-sensitive and insensitive) were estimated in a group of female patients suffering from mania and repeated on about two thirds of them when they had recovered. With recovery there was a statistically significant increase in the erythrocyte ouabain-sensitive potassium influx. The other parameters showed no significant overall change with recovery but the initial severity correlated significantly and negatively with the change in erythrocyte Na-K ATPase with recovery. The changes that occurred in the erythorcyte sodium concentration and Na-K ATPase activity were not random since they correlated significantly with changes in the active potassium influx.

Whole blood adenosine triphosphate in manic-depressive illness.

Whole blood cell ATP concentration was estimated in a group of manic and depressed patients and in a group of normal subjects. There were no significant differences between patient and control groups, nor in the patient groups were there any significant changes with recovery.

Plasma tryptophan concentration in depressive illness and mania.

Total and free plasma trytophan levels were measured in depressive and manic patients before and after recovery. No change was found in total or free plasma trytophan concentration on recovery from depressive illness. Free plasma tryptophan levels were higher in recovered manics than in active manics, and a group of four manic patients tested before and after recovery showed a significant increase in free plasma tryptophan concentration on recovery.

Plasma total and free tryptophan concentration in 'neurotic' and 'psychotic' depressive patients.

Plasma levels of total and free tryptophan were measured in patients with depressive neurosis and depressive psychosis, before and after recovery. No significant differences were found in total or free plasma tryptophan levels between 'neurotic' and 'psychotic' groups, and no change in these levels was found on recovery from depressive illness.

Trial of digoxin in mania.

A suggestion that mania is associated with an increased membrane transport of sodium has been investigated in a double-blind trial of a specific Na-K A.T.P.ase inhibitor (digoxin) in twelve female inpatients with mania. Digoxin had no effect.

Lithium in non-manic-depressives: antiaggressive effect and red blood cell lithium values.

Lithium was given to eight aggressive, non-manic-depressive female defectives in a doubleblind placebo-controlled study. The group as a whole showed a reduction in aggression scores while on lithium (p greater than 0.01): three patients became less aggressive,one became worse and two were unchanged. Both affective and predatory aggression seemed to be reduced. Two patients had to be withdrawn from the trial at an early stage because of the development of neurotoxicity.