Pharmacokinetics and disposition of a novel NMDA glycine site antagonist (UK-240,455) in rats, dogs and man

1. UK-240,455 ((+) 6,7-dichloro-5-[N-(2-hydroxyethyl)methanesulphonamido]-2,3 (1H,4H)-quinoxalinedione) is a potent, selective N-methyl D-aspartate (NMDA) glycine site antagonist that is being evaluated for the potential treatment of stroke. 2. UK-240,455 is predominately excreted unchanged in urine (58-68%) in rats, dogs and man following intravenous administration. The remainder of the dose is excreted unchanged in the faeces. It is considered that UK-240,455 is predominantly cleared by active renal tubular secretion and active hepatobiliary transport. In man, there is evidence that UK-240,455 undergoes glucuronidation. However, there is no evidence for this in rats and dogs. 3. UK-240,455 has a short elimination half-life in rats, dogs and man (0.4-1.4 h) and clearances of 12, 13 and 6 ml min(-1) kg(-1), respectively. The compound shows limited tissue distribution with volumes of distribution of 0.4-0.8 l kg(-1) in rats, dogs and man. The species' variation in pharmacokinetic parameters was related allometrically when plasma protein binding was taken in to account. Hence, active hepatic or renal clearance processes for this compound were conserved across species. 4. Cerebrospinal fluid and brain concentrations of UK-240,455 were determined in rats. The cerebrospinal fluid/plasma concentration ratio of UK-240,455 was 4.3%, which was similar to the plasma-free fraction of this compound (3%), indicating good blood-brain barrier permeability. Brain tissue concentrations were low (0.7% of the total plasma concentrations).

Physical mapping of autonomic/sympathetic candidate genetic loci for hypertension in the human genome: a somatic cell radiation hybrid library approach

Allelic variation at multiple genetic loci may contribute to hypertension. Since autonomic/sympathetic dysfunction may play an early, pathogenic, heritable role in hypertension, we evaluated candidate loci likely to contribute to such dysfunction, including catecholamine biosynthetic enzymes, catecholamine transporters, neuropeptides, and adrenergic receptors. Since chromosomal locations and physical map positions of many of these loci had not yet been identified, we used the GeneBridge4 human/hamster radiation (somatic cell) hybrid library panel (resolution approximately 1 to approximately 1.5 Mb), along with specifically designed oligonucleotide primers and PCR (200-400 bp products) to position these loci in the human genome. Primers were designed from sequences outside the coding regions (3'-flanking or intronic segments) to avoid cross-species (hamster) amplification. Chromosomal positions were assigned in cR (centi-Ray) units ( approximately 270 Kbp/cR(3000) for GeneBridge 4). A total of 13 loci were newly assigned chromosomal positions; of particular interest was a cluster of adrenergic candidate loci on chromosome 5q (including ADRB2, ADRA1A, DRD1, GPRK6, and NPY6R), a region harbouring linkage peaks for blood pressure. Such physical map positions will enable more precise selection of polymorphic microsatellite and single nucleotide polymorphism markers at these loci, to aid in linkage and association studies of autonomic/sympathetic dysfunction in human hypertension.

Genetic parentage assessment in the crayfish Orconectes placidus, a high-fecundity invertebrate with extended maternal brood care

Microsatellite data have recently been introduced in the context of genetic maternity and paternity assignments in high-fecundity fish species with single-parent-tended broods. Here we extend such analyses to an aquatic invertebrate, the crayfish Orconectes placidus, in which gravid females carry large numbers of offspring. Genetic parentage analyses of more than 900 progeny from 15 wild crayfish broods revealed that gravid females were invariably the exclusive dams of the offspring they tended (i.e. there was no allomaternal care), and that most of the females had mated with multiple (usually two) males who contributed sometimes highly skewed numbers of offspring to a brood. Within any multiply sired brood, the unhatched eggs (or the hatched juveniles) from different fathers were randomly distributed across the mother's brood space. All of these genetic findings are discussed in the light of observations on the mating behaviours and reproductive biology of crayfish.

Les Schwab tire centers leads the way in dental insurance

A family-owned retail tire company has a successful history with direct reimbursement for dental and other health care benefits. Although there is a co-pay and some elective services are not covered, employees are not asked to fund insurance premiums and freedom of choice with regard to provider is ensured. This approach is grounded in the family orientation of the company.

Localization of indoleamine 2,3-dioxygenase and 4-hydroxynonenal in normal and pre-eclamptic placentae

This study was undertaken to compare placental levels of 2,3-Dioxygenase (IDO), a free radical scavenger, and 4-Hydroxynonenal (4-HNE), a major by-product of lipid peroxidation, in normal and pre-eclamptic pregnancies. Placentae were collected at caesarean section from women with a term, normal singleton pregnancy (37-40 weeks' gestation, n=10) and women with a term singleton pregnancy complicated by pre-eclampsia (n=10). IDO and 4-HNE localization and intensity was studied by semi-quantitative immunohistochemistry and differences between groups were analysed using the Mann-Whitney U test. Immunostaining for IDO was located primarily in endothelial cell nuclei, with a reduced level of staining in the cytoplasm, in most capillaries from all placentae examined. A significantly higher level of IDO immunostaining was observed in normal placentae compared to pre-eclamptic placentae (P=0.008). 4-HNE was located mainly in the cytoplasm of syncytiotrophoblast cells of all placentae examined. There were no significant differences in the pattern or intensity of 4-HNE immunostaining levels between normal and pre-eclamptic pregnancies (P=0.684). Our IDO results support the hypothesis of decreased anti-oxidative capability in the placenta and the possibility of an ineffective compensatory mechanism against increased oxidative stress in the fetus.

Genetic abnormalities detected in ependymomas by comparative genomic hybridisation

Using comparative genomic hybridisation, we have analysed genetic imbalance in a series of 86 ependymomas from children and adults. Tumours were derived from intracranial and spinal sites, and classified histologically as classic, anaplastic or myxopapillary. Ependymomas showing a balanced profile were significantly (P<0.0005) more frequent in children than adults. Profiles suggesting intermediate ploidy were common (44% of all tumours), and found more often (P<0.0005) in tumours from adults and the spinal region. Loss of 22q was the most common specific abnormality, occurring in 50% of spinal (medullary) ependymomas and 26% of tumours overall. Genetic profiles combining loss of 22q with other specific abnormalities--gain of 1q, loss of 6q, loss of 10q/10, loss of 13, loss of 14q/14--varied according to site and histology. In particular, we showed that classic ependymomas from within the cranium and spine have distinct genetic profiles. Classic and anaplastic ependymomas with gain of 1q tended to occur in the posterior fossa of children and to behave aggressively. Our extensive data on ependymomas demonstrate significant associations between genetic aberrations and clinicopathological variables, and represent a starting point for further biological and clinical studies.

Minilaparotomy and endoscopic techniques for tubal sterilisation

BACKGROUND

Worldwide, the most commonly used method of fertility regulation is tubal sterilisation. In developed countries sterilisation is generally performed by laparoscopy rather than by minilaparotomy, based on the belief that this approach is both safe and effective. In developing countries, where the resources are limited for the purchase and maintenance of the more sophisticated laparoscopic equipment, minilaparotomy may still be the most common approach. In both resource poor and industrialised countries using the technique with the greatest effectiveness and safety, together with the least costs, is extremely important. Though both methods are widely used, the advantages and disadvantages of laparoscopic sterilisation compared to mini-laparotomy have not been systematically evaluated. The ideal method would be one which is highly effective, economical, able to be performed on an outpatient basis, allowing rapid resumption of normal activity, producing a minimal or invisible scar and having a potential for reversibility. This review considers the methods to enter the abdominal cavity through the abdominal wall, either by minilaparotomy, laparoscopy or culdoscopy regardless of the technique used for tubal sterilisation.

OBJECTIVES

To evaluate laparoscopic tubal sterilisation, as compared to minilaparotomy in terms of operative morbidity and mortality. Trials comparing laparoscopy or minilaparotomy with culdoscopy were also included in the review. Different methods used to interrupt tubal patency (excision, occlusion and coagulation) and comparison of different forms of anaesthesia will be considered in different reviews.

SEARCH STRATEGY

Randomised controlled trials (RCTs) have been identified by using the search strategy of the Cochrane Collaboration. The Cochrane Controlled Trials Register was last searched in 1999 (Cochrane Library Issue 4, 1999). Reference lists of identified trials have been searched.

SELECTION CRITERIA

All randomised controlled trials comparing laparoscopy, minilaparotomy and/or culdoscopy for tubal sterilisation. Except in one trial [Taner 1994] where 4 women underwent curettage at the same time, all women requested tubal sterilisation as an interval procedure.

DATA COLLECTION AND ANALYSIS

Trials under consideration were evaluated for methodological quality and appropriateness for inclusion. Data were extracted independently by the reviewers. Results are reported as odds ratio for dichotomous outcomes and weighted mean differences for continuous outcomes.

MAIN RESULTS

Minilaparotomy vs laparoscopy: There was no difference in major morbidity between the 2 groups. Minor morbidity was significantly less in the laparoscopy group (Peto OR 1.89; 95% CI 1.38, 2.59). Duration of operation was about 5 minutes shorter in the laparoscopy group (WMD 5.34; 95% CI 4.52, 6.16). Minilaparotomy vs culdoscopy: Women undergoing culdoscopy had more major morbidity than women for whom minilaparotomy was performed (Peto OR 0.14; 95% CI 0.02, 0.98). Duration of operation was about 5 minutes shorter in women undergoing culdoscopy (WMD 4.91; 95% CI 3.82, 6.01). Laparoscopy vs culdoscopy: In the one trial comparing the two interventions there were no significant differences between the groups with regard to major morbidity. Significantly more women suffered from minor morbidities in the culdoscopy group compared to the laparoscopy group (Peto OR 0.20; 95% CI 0.05, 0.77).

REVIEWER'S CONCLUSIONS

Major morbidity seems to be a rare outcome for both, laparoscopy and minilaparotomy. The included studies had limited power to demonstrate significant differences especially for the relatively rare but potentially serious outcomes. Personal preference of the woman and/or of the surgeon can guide the choice of technique. Practical aspects (e.g. cost, maintenance, and sterilisation of the instruments) must be taken into account before implementing the more sophisticated endoscopic techniques in settings with limited resources. Culdoscopy is not recommended as it carries a higher complication rate.

Genetic evidence for extreme polyandry and extraordinary sex-role reversal in a pipefish

Due to the phenomenon of male pregnancy, the fish family Syngnathidae (seahorses and pipefishes) has historically been considered an archetypal example of a group in which sexual selection should act more strongly on females than on males. However, more recent work has called into question the idea that all species with male pregnancy are sex-role reversed with respect to the intensity of sexual selection. Furthermore, no studies have formally quantified the opportunity for sexual selection in any natural breeding assemblage of pipefishes or seahorses in order to demonstrate conclusively that sexual selection acts most strongly on females. Here, we use a DNA-based study of parentage in the Gulf pipefish Syngnathus scovelli in order to show that sexual selection indeed acts more strongly on females than on males in this species. Moreover, the Gulf pipefish exhibits classical polyandry with the greatest asymmetry in reproductive roles (as quantified by variances in mating success) between males and females yet documented in any system. Thus, the intensity of sexual selection on females in pipefish rivals that of any other taxon yet studied.

Mechanism and cleavage specificity of the H-N-H endonuclease colicin E9

Colicin endonucleases and the H-N-H family of homing enzymes share a common active site structural motif that has similarities to the active sites of a variety of other nucleases such as the non-specific endonuclease from Serratia and the sequence-specific His-Cys box homing enzyme I-PpoI. In contrast to these latter enzymes, however, it remains unclear how H-N-H enzymes cleave nucleic acid substrates. Here, we show that the H-N-H enzyme from colicin E9 (the E9 DNase) shares many of the same basic enzymological characteristics as sequence-specific H-N-H enzymes including a dependence for high concentrations of Mg2+ or Ca2+ with double-stranded substrates, a high pH optimum (pH 8-9) and inhibition by monovalent cations. We also show that this seemingly non-specific enzyme preferentially nicks double-stranded DNA at thymine bases producing 3'-hydroxy and 5'-phosphate termini, and that the enzyme does not cleave small substrates, such as dinucleotides or nucleotide analogues, which has implications for its mode of inhibition in bacteria by immunity proteins. The E9 DNase will also bind single-stranded DNA above a certain length and in a sequence-independent manner, with transition metals such as Ni2+ optimal for cleavage but Mg2+ a poor cofactor. Ironically, the H-N-H motif of the E9 DNase although resembling the zinc binding site of a metalloenzyme does not support zinc-mediated hydrolysis of any DNA substrate. Finally, we demonstrate that the E9 DNase also degrades RNA in the absence of metal ions. In the context of current structural information, our data show that the H-N-H motif is an adaptable catalytic centre able to hydrolyse nucleic acid by different mechanisms depending on the substrate and metal ion regime.

Economic analysis of tuberculosis diagnostic tests in disease control: how can it be modelled and what additional information is needed?

As the goal of tuberculosis (TB) control programmes is to get as many cases as possible onto correct treatment, the critical role of diagnosis is obvious. Under-diagnosis contributes to further spread of the disease, while over-diagnosis wastes scarce resources on inappropriate treatment. Various techniques are available with which to diagnose TB, including sputum smear microscopy, chest X-ray, antibiotics and culture. While it may be possible to improve the application of these diagnostic tools, there is universal recognition of their limitations. Although new technologies have been developed, their appropriateness for use in resource-poor settings has been questioned due to concerns associated with their complexity and high cost. Given the constrained resources of most countries heavily affected by TB, economic evaluation provides a powerful tool to facilitate the prioritisation of resources. However, economic appraisals of diagnostic procedures provide several unique methodological challenges, including specification of appropriate alternatives, measuring costs, and measuring outcomes. Nevertheless, the use of decision analytic models can provide an opportunity to explore many of these issues. This paper presents key problems in the diagnostic process, reviews existing diagnostic techniques, and discusses possible improvements of these techniques and the introduction of new techniques. Next it examines the usefulness of modelling the economics of TB diagnosis, highlighting gaps in information requirements. Finally, the article identifies economic and epidemiological factors that are likely to change results in different settings.