Long-term performance of Tec vaporizers

We reviewed the maintenance records of Tec vaporizers which had been in clinical use for up to 4 years. Tec 4s and Enfluratec 3s were found to be extremely reliable, but Fluotec 3s suffered progressively from mechanical and calibration problems. Their most recurrent fault was sticking valves caused probably by thymol crystallizing on the valve faces. This fault did not occur with Fluotec 4s, which are designed to prevent liquid agent reaching the valve surfaces. We found, in a study of the effects of thymol accumulation, that only occasional draining of a Fluotec vaporizer is required to keep thymol concentration below the level at which its output is reduced. We conclude that, if regular field calibration checks are carried out as a safety measure, the service interval for Tec vaporizers could be extended beyond Ohmeda's present recommendation of one year.     

Ookinete antigens of Plasmodium berghei. Appearance on the zygote surface of an Mr 21 kD determinant identified by transmission-blocking monoclonal antibodies

Zygotes and ookinetes of the rodent malaria Plasmodium berghei can be enriched 50-fold, from whole blood cultures by ammonium chloride lysis. Three monoclonal antibodies (MoAbs) raised against such enriched preparations specifically bind to a determinant of Mr 21 kD as assessed by 125I-labelled goat anti-mouse IgG probed immunoblots of Western transfers of SDS-PAGE gels. Indirect immunofluorescence indicates that the 21 kD determinant bound by specific MoAbs, whilst not detectable on gametocytes or gametes, appears on the parasite surface within 2 h of exflagellation/fertilization and increases thereafter. The three MoAbs specifically binding the 21 kD determinant block oocyst development in mosquitoes by at least 90%, as assessed either by in-vitro membrane feeds or by live feeds on passively immunized mice. These MoAbs reduce ookinete formation in vitro by between 52 and 100%. Possible mechanisms of action of these MoAbs are discussed.     

Developing methodologies for evaluating community-wide health promotion

There has been growing recognition that health promotion programswhich target whole communities are more likely to be effectivein changing health behaviour. However, studies evaluating theimpact of community-wide health promotion programs rarely useadequate methodology. Randomised control trials where multiplewhole communities are randomly assigned to control and interventiongroups are optimum if evaluators hope to validly attribute changesin health behaviour to the intervention. However, such trialspresent a number of difficulties including cost and feasibilitylimitations and the evolving nature of statistical techniques.This paper proposes applying a fairly well-accepted phased evaluationapproach to the evaluation of community participation programs,using three defined phases. Phase 1 consists of small-scalestudies to develop the measures and assess acceptability andfeasibility of the intervention; Phase 2 consists of studiesin a small number of communities designed to trial the interventionin the real world; Phase 3 studies use an appropriate numberof entire communities to provide valid evidence of efficacyof the intervention. It is suggested that criteria be resolvedto identify adequate studies at each stage and that advantagesand limitations of Phase 1 and 2 studies be clearly identified.The paper describes the major design, sampling and analysisconsiderations for a Phase 3 study.     

Vasoactive intestinal peptide immunoreactive nerve fibres are deficient in intestinal and nasal mucosa affected by cystic fibrosis

Cystic fibrosis (CF) is the most common lethal or debilitating inherited disease amongst Caucasians, with estimates of its frequency of occurrence in this population ranging from 1: 2000 to 1: 15 000 live births. It is characterized by disorders of exocrine secretions, primarily of the skin, respiratory tract and digestive system. The secretory processes of these tissues are influenced by autonomic nerve fibres, many of which contain regulatory peptides. The innervation of the intestinal and respiratory mucosa of CF patients has been investigated in order to determine if there is any derangement of the peptide-containing nerve fibres that supply these tissues. The present work demonstrates that, in CF, there is a deficiency of vasoactive intestinal peptide immunoreactivity (VIP-IR) in nerve fibres in the nasal and intestinal mucosa. There is not a generalized loss of fibres that are immunoreactive for this peptide, however, since VIP-IR fibres innervating the intestinal muscle are largely unaffected. Moreover, other types of nerve fibres innervating the nasal mucosa and the mucosa of the intestinal villi appear to be unaffected in CF patients. Physiological evidence indicates that vasoactive intestinal peptide is contained in secretomotor neurons and is a powerful stimulant of secretion; loss of function restricted to these neurons is consistent with the clinical manifestations of CF.     

EVALUATION OF KEYED FILLERS ON TEC VAPORIZERS

Single and dual port versions of the keyed fillers fitted toTEC4 and TEC3 vaporizers, respectively, were examined. The singleport filler performed satisfactorily, provided that it was correctlyused and properly maintained. Design deficiencies in the dual-portkeyed filler were found which accounted for many of the problemsdescribed by users. The keyed bottle adaptor could be improvedby an increase in its length and the provision of two openingsinto the outer tube at the bottle ends.     

Metabolism and Excretion of Gallium Arsenide and Arsenic Oxides by Hamsters following Intratracheal Instillation

The increasing use of gallium arsenide (GaAs) in the electronicsindustry has produced the need for pharmacokinetic and toxicologicdata on GaAs. The disposition in male Syrian golden hamsters(n = 4) following intratracheal instillation of GaAs (mean volumediameter 5.8 µm), arsenic(III) oxide (arsenite), and arsenic(V)oxide (arsenate) at a dose of 5 mg/kg body weight was examined.Blood, kidney, liver, and lung samples were collected at 1,2, and 4 days after administration. Excreta were collected daily.Urinary metabolite profiles were determined after separationon a mixed anion–cation-exchange column. Total As contentwas analyzed by direct hydride flame atomic absorption spectrophotometryafter digestion. Arsenic blood levels after GaAs, arsenite,and arsenate administration were 0.185 ± 0.041, 0.596± 0.117, and 0.3 10 ± 0.045 ppm, respectively,after Day 1. Arsenic blood levels after GaAs administrationincreased to 0.279 ± 0.021 ppm on Day 2 indicating continuedabsorption while levels decreased for the arsenite and arsenategroups. At Day 1 the liver contained 0.565 ± 0.036, 2.62± 0.26, and 0.579 ± 0.144% of the arsenic doseof GaAs, arsenite, and arsenate, respectively. The" arseniteand arsenate were rapidly excreted in the urine with almosthalf the dose appearing after 4 days; in contrast, only about5% of the GaAs was found at the corresponding time. Total recoveries,as arsenic equivalents, for the three compounds were between75 and 80%. Ratios of the two major urinary metabolites (dimethylarsinicacid/total Inorganic As species) were 1.41, 1.71, and 0.983for GaAs, arsenite, and arsenate, respectively. GaAs is metabolizedto the same compounds as arsenite and arsenate, and shows ametabolic profile most similar to that observed for sodium arsenite.     

The diagnosis of polycystic ovaries in subfertile women

Summary. Laparoscopy was used to identify the polycystic ovary (PCO) in a group of subfertile women. A third were found to have PCO. These patients had higher levels of luteinizing hormone (LH), testosterone (T) and a higher free androgen index (FAI) than those with normal ovaries. Only 15% of patients with laparoscopic evidence of PCO were obese, hirsute and oligomenorrhoeic. Within the PCO group, hirsutism was strongly associated with obesity and a high FAI. A group of subfertile women with PCO and regular cycles was found who had no other identifiable cause for their infertility. These women had higher follicular phase concentrations of LH and higher FAI than ovulatory women with normal ovaries.