Critical determinants of host receptor targeting by Neisseria meningitidis and Neisseria gonorrhoeae: identification of Opa adhesiotopes on the N-domain of CD66 molecules

The human pathogens Neisseria meningitidis and Neisseria gonorrhoeae express a family of variable outer membrane opacity-associated (Opa) proteins that recognize multiple human cell surface receptors. Most Opa proteins target the highly conserved N-terminal domain of the CD66 family of adhesion molecules, although a few also interact with heparan sulphate proteoglycans. In this study, we observed that at least two Opa proteins of a N. meningitidis strain C751 have the dual capacity to interact with both receptors. In addition, all three Opa proteins of C751 bind equally well to HeLa cells transfected with cDNA encoding the carcinoembryonic antigen [CEA (CD66e)] subgroup of the CD66 family, but show distinct tropism for CGM1- (CD66d) and NCA (CD66c)-expressing cells. Because the C751 Opa proteins make up distinct structures via the surface-exposed hypervariable domains (HV-1 and HV-2), these combinations appear to be involved in tropism for the distinct CD66 subgroups. To define the determinants of receptor recognition, we used mutant proteins of biliary glycoprotein [BGP (CD66a)] carrying substitutions at several predicted exposed sites in the N-domain and compared their interactions with several Opa proteins of both N. meningitidis and N. gonorrhoeae. The observations applied to the molecular model of the BGP N-domain that we constructed show that the binding of all Opa proteins tested occurs at the non-glycosylated (CFG) face of the molecule and, in general, appears to require Tyr-34 and Ile-91. Further, efficient interaction of distinct Opa proteins depends on different non-adjacent amino acids. In the three-dimensional model, these residues lie in close proximity to Tyr-34 and Ile-91 at the CFG face, making continuous binding domains (adhesiotopes). The epitope of the monoclonal antibody YTH71.3 that inhibits Opa/CD66 interactions was also identified within the Opa adhesiotopes on the N-domain. These studies define the molecular basis that directs the Opa specificity for the CD66 family and the rationale for tropism of the Opa proteins for the CD66 subgroups.

TeV Observations of Markarian 501 with the Milagrito Water Cerenkov Detector

The Milagrito water Cerenkov detector near Los Alamos, New Mexico, was operated as a sky monitor at energies of a few TeV between 1997 February and 1998 May, including the period of the strong, long-lasting 1997 flare of Markarian 501. Milagrito served as a test run for the full Milagro detector. An event excess with a significance of 3.7 sigma from Markarian 501 was observed, in agreement with expectations.

Lack of association between a human beta-2 adrenoceptor gene polymorphism (gln27glu) and morbid obesity

OBJECTIVE

To determine the frequency of the gln27glu polymorphism in the beta-2 adrenoceptor gene in patients with morbid obesity.

SUBJECTS

243 patients with morbid obesity (mean body mass index 51. 6) and 199 healthy blood donors.

RESULTS

The same frequency, 0.42, of the glu allele was observed in both groups. Neither the incidence in obese women (0.41, n=197) compared to control women (0.43, n=61), nor that in obese men (0.44, n=46) compared to control men (0.41, n=138) was significantly different. The difference in frequency between obese men and women, 0.44 vs 0.41 was not significant (P=0. 68). Genotype information from the families of 18 of the obese patients showed no association between the glu27 allele and BMI.

CONCLUSIONS

We find no evidence for a role of the glu27 variant in the beta-2 adrenoceptor gene in the development of morbid obesity.

Inhibition of kinin action and kinin generation compared to dexamethasone pretreatment with respect to vascular effects and pancreatic enzymes in experimental acute pancreatitis

It was determined earlier that inhibition of the action of endogenous kinins by the bradykinin B2 antagonist, icatibant (Hoe-140; D-Arg-[Hyp3, Thi5, D-Tic7, Oic8]-bradykinin), prevents pancreatic oedema formation during caerulein-induced acute pancreatitis, and simultaneously improves the egress of activated pancreatic enzymes from the pancreas. We have now investigated whether inhibition of increases in vascular permeability by another approach, i.e., pretreatment with dexamethasone, would have comparable effects. In addition, preliminary data are presented on the effects of the selective low molecular weight inhibitor of tissue kallikrein, H-(4-Cl)-D-Phe-1Nal-(3-aminopropyl)-guanidine (CH-2856). Icatibant abolished plasma extravasation into the pancreatic tissue and prevented the development of hypovolaemia. Caerulein-induced increases of amylase activity in the pancreas were significantly reduced by icatibant, while amylase activity in blood was augmented. Inhibition of kinin generation by CH-2856 had similar effects, as oedema formation was inhibited and enzyme activities were reduced in the pancreas and augmented in the blood serum. Dexamethasone completely abolished oedema formation, but only partially inhibited the development of hypovolaemia and haemoconcentration. Amylase activities in the pancreas and in blood remained completely unaffected by dexamethasone. The results suggest that retention of activated enzymes in the pancreatic tissue during acute pancreatitis involves a B2 receptor-mediated, but glucocorticoid-insensitive mechanism.

Half of Saccharomyces cerevisiae carbamoyl phosphate synthetase produces and channels carbamoyl phosphate to the fused aspartate transcarbamoylase domain

The first two steps of the de novo pyrimidine biosynthetic pathway in Saccharomyces cerevisiae are catalyzed by a 240-kDa bifunctional protein encoded by the ura2 locus. Although the constituent enzymes, carbamoyl phosphate synthetase (CPSase) and aspartate transcarbamoylase (ATCase) function independently, there are interdomain interactions uniquely associated with the multifunctional protein. Both CPSase and ATCase are feedback inhibited by UTP. Moreover, the intermediate carbamoyl phosphate is channeled from the CPSase domain where it is synthesized to the ATCase domain where it is used in the synthesis of carbamoyl aspartate. To better understand these processes, a recombinant plasmid was constructed that encoded a protein lacking the amidotransferase domain and the amino half of the CPSase domain, a 100-kDa chain segment. The truncated complex consisted of the carboxyl half of the CPSase domain fused to the ATCase domain via the pDHO domain, an inactive dihydroorotase homologue that bridges the two functional domains in the native molecule. Not only was the "half CPSase" catalytically active, but it was regulated by UTP to the same extent as the parent molecule. In contrast, the ATCase domain was no longer sensitive to the nucleotide, suggesting that the two catalytic activities are controlled by distinct mechanisms. Most remarkably, isotope dilution and transient time measurements showed that the truncated complex channels carbamoyl phosphate. The overall CPSase-ATCase reaction is much less sensitive than the parent molecule to the ATCase bisubstrate analogue, N-phosphonacetyl-L-aspartate (PALA), providing evidence that the endogenously produced carbamoyl phosphate is sequestered and channeled to the ATCase active site.

Developing strategies to control schistosomiasis morbidity in nonenrolled school-age children: experience from Egypt

Schistosomiasis is a major health problem in school-age children in much of the tropical world. They harbour the most intense infections for both Schistosoma mansoni and S. haematobium. In Egypt, the Ministry of Health and Population (MOHP) has implemented a successful school-based treatment programme in which children are screened and those found to be infected treated with praziquantel. High nonenrolment rates in some rural areas have a negative impact on the coverage of this programme and on its ability to reduce transmission in the community. The main aim of our study was to introduce and test a simple intervention to extend treatment to nonenrolled children using the routine MOHP schistosomiasis treatment programme. Twenty villages or ezbas in Tamia district, Fayoum governorate, with 8 schools and 1901 nonenrolled children were targeted. 88.5% of nonenrolled children attended schools to avail themselves of treatment. Coverage rates were significantly higher for girls (P < 0.001). These results are important for countries where schistosomiasis is endemic. They suggest that offering interventions in schools may not only improve the health of school attendees but also be an affordable way of extending services to out-of-school children.

Electrophysiological and clinical comparison of two temporary pacing leads following cardiac surgery

Temporary pacing leads are invaluable in diagnosis and treatment of arrhythmia after cardiac surgery. The ideal lead possesses reliable pacing and sensing capabilities throughout the postoperative period. Ease of handling and a low complication rate are essential. This study compares a new lead (Medtronic model #6492) to a temporary pacemaker lead established in clinical use (Medtronic model #6500). One lead of each type was placed in the right atrium and ventricle in 33 patients undergoing elective coronary revascularization. Pacing function was measured on the first and fourth postoperative days. Lead complications were documented. On day 1, there was no statistical difference between lead types in terms of pacing (voltage threshold, current threshold), impedance, or sensing (P wave amplitude, R wave amplitude). On day 4, both leads showed an increase in pacing threshold and a decrease in sensing ability. The only statistical difference between lead types was in atrial sensing on day 4, as measured by the P wave amplitudes (1.95 +/- 0.18 V for model 6492 vs 1.40 +/- 0.14 V for model 6500, P < 0.05). Two leads of each model failed to pace in the ventricular position and one lead in each model in the atrial position. There were no complications attributable to either pacemaker lead. We found that both lead types were reliable and functioned well. The Medtronic Model #6492 lead demonstrated better long-term sensing, although in this study the difference was not clinically significant.

Airway epithelial tight junctions and binding and cytotoxicity of Pseudomonas aeruginosa

The role of tight junctions in the binding and cytoxicity of Pseudomonas aeruginosa to apical or basolateral membranes of lung airway epithelial cells was tested with fluorescence microscopy on living cells. Binding of noncytotoxic P. aeruginosa strain O1 was assessed with P. aeruginosa that expressed green fluorescent protein. Binding of cytotoxic P. aeruginosa strain 6206 was assessed with FITC-labeled P. aeruginosa; cytotoxicity was determined from nuclear uptake of the impermeant dye propidium iodide. The role of direct contact of P. aeruginosa to epithelial cells was tested with filters with small (0.45-micrometer) or large (2.0-micrometer) pores. High transepithelial resistance (R(t)) Calu-3 and cultured bovine tracheal monolayers (R(t) > 1,000 Omega. cm(2)) bound P. aeruginosa very infrequently (<1 P. aeruginosa/100 cells) at the apical membrane, but P. aeruginosa bound frequently to cells near "free edges" at holes, wounds, islands, and perimeters; cytotoxicity required direct interaction with basolateral membranes. Wounded high R(t) epithelia showed increased P. aeruginosa binding and cytotoxicity at the free edges because basolateral membranes were accessible to P. aeruginosa, and dead and living cells near the wound bound P. aeruginosa similarly. Compared with high R(t) epithelia, low R(t) CFT1 (R(t) = 100-200 Omega. cm(2)) and EGTA-treated Calu-3 monolayers were 25 times more susceptible to P. aeruginosa binding throughout the monolayer. Cytotoxicity to CFT1 cells (throughout the confluent monolayer, not only at the free edge) occurred after a shorter delay (0.25 vs. 2.0 h) and then five times faster than to Calu-3 cells, indicating that the time course of P. aeruginosa cytotoxicity may be limited by the rate of gaining access through tight junctions and that this occurred faster in low R(t) than in high R(t) airway epithelia. Cytotoxicity appeared to occur in a sequential process that led first to a loss of fura 2 and a later uptake of propidium iodide. P. aeruginosa bound three times more frequently to regions between cells (tight junctions?) than to cell membranes of low R(t) CFT1 cells.

The privatised water industry and public health: back to square one

No real progress has taken place in implementing new water fluoridation schemes within the UK since the ownership of most water companies passed into the private sector. A recent High Court judgement has confirmed that English water companies have absolute and unfettered discretion in deciding not to proceed with any new fluoridation schemes. Current legislation must be changed if this important public health measure is to be extended to benefit a greater number of people.

Crystallization and preliminary X-ray diffraction analysis of a biologically active fragment of CD55

Crystals have been grown of two of the domains of CD55. This is the first report of crystallization of a short consensus repeat (SCR) domain containing protein. CD55 is a widely expressed polymorphic glycoprotein, which functions as a complement regulator by inhibiting assembly and promoting destruction of C3 and C5 convertases. As a key regulator of complement, CD55 is implicated in the hyperacute rejection of xenografts from pigs into primates. It is also commonly hijacked as a receptor by viruses (e.g. medically important echoviruses and coxsackieviruses) and bacterial pathogens (e.g. certain pathogenic strains of Escherichia coli). Here, crystallization of a virus-binding fragment expressed in yeast, consisting of two of the four extracellular SCR domains of CD55, is reported. The recombinant domains have been crystallized in 30% polyethylene glycol (PEG), 0.2 M sodium acetate, 0.1 M sodium acetate trihydrate pH 4.6 using the sitting-drop vapour-diffusion method. Two crystal forms are observed (orthorhombic and monoclinic) and a native data set to 1.65 A resolution has been collected from the monoclinic form at the Synchrotron Radiation Source, Daresbury, UK.

Effect of material deprivation on Epstein-Barr virus infection in Hodgkin's disease in the West Midlands

We have used Townsend scores from postcode data to compare levels of material deprivation and Epstein-Barr virus (EBV)-positivity for 223 patients diagnosed with Hodgkin's disease (HD) in the period 1981-1997. The presence of EBV in HD tumours was determined using in situ hybridization to target the abundantly expressed EBV early RNAs. EBV was detected in the malignant Hodgkin and Reed-Sternberg cells in 47/223 HD cases (21%). There was found to be a tendency for higher Townsend scores (indicative of higher levels of material deprivation) in EBV-positive HD patients, but this association was not statistically significant. When various subgroups of patients from the study were examined separately the indication of higher Townsend scores in EBV-positive patients was found to be more marked for patients with mixed cellularity disease (P = 0.09) and for females (P = 0.03). The results of this study suggest that differences in the level of material deprivation are important in determining the likelihood of EBV-positive HD in the UK, particularly for certain subgroups of patients. It is not known what specific socioeconomic factors are responsible for these differences, although alterations in the timing or rate of primary EBV infection, or decline in the level of EBV-specific immunity, may be important.

Acute health effects of the Sea Empress oil spill

STUDY OBJECTIVE

To investigate whether residents in the vicinity of the Sea Empress tanker spill suffered an increase in self reported physical and psychological symptoms, which might be attributable to exposure to crude oil.

DESIGN

Retrospective cohort study; postal questionnaire including demographic details, a symptom checklist, beliefs about health effects of oil and the Hospital Anxiety and Depression and SF-36 mental health scales.

SETTING

Populations living in four coastal towns on the exposed south Pembrokeshire coast and two control towns on the unexposed north coast.

PATIENTS

539 exposed and 550 unexposed people sampled at random from the family health services authority age-sex register who completed questionnaires.

MAIN RESULTS

Adjusted odds ratios for self reported physical symptoms; scores on the Hospital Anxiety and Depression and SF-36 mental health scales, in 1089 people who responded out of a possible 1585 (69%).

CONCLUSIONS

Living in areas exposed to the crude oil spillage was significantly associated with higher anxiety and depression scores, worse mental health; and self reported headache (odds ratio = 2.35, 95% CI 1.56, 3.55), sore eyes (odds ratio = 1.96, 95% CI 1.06, 3.62), and sore throat (odds ratio = 1.70, 95% CI 1.12, 2.60) after adjusting for age, sex, smoking status, anxiety, and the belief that oil had affected health. People living in exposed areas reported higher rates of physical and psychological symptoms than control areas. Symptoms significantly associated with exposure after adjustment for anxiety and health beliefs were those expected from the known toxicological effect of oil, suggesting a direct health effect on the exposed population.

Vascular surgical society of great britain and ireland: transcranial doppler-directed dextran therapy in the prevention of postoperative carotid thrombosis

BACKGROUND: Evidence suggests that embolization precedes carotid thrombosis, a previously unpredictable event complicating 2-3 per cent of all carotid endarterectomies. It was hypothesized that dextran 40 therapy might prevent progression to complete thrombosis in high-risk patients. METHODS: Between October 1995 and July 1998, 400 consecutive patients were monitored following carotid endarterectomy using transcranial Doppler ultrasonography. Those with sustained embolization (more than 25 in 10 min) or those with emboli that distorted the middle cerebral artery waveform were commenced on an incremental dextran 40 infusion. RESULTS: Two hundred and sixteen patients (54 per cent) had one or more emboli detected (96 per cent within 2 h of flow restoration) but only 15 (4 per cent) required dextran therapy. Embolization ceased in each case although the dextran dose had to be adjusted in four. In one of the latter patients, embolization recurred on day 5 but was again controlled with high-dose dextran. Overall, the death and any stroke rate was 2 per cent and no patient suffered a stroke due to carotid thrombosis. CONCLUSION: A few patients develop sustained embolization following carotid endarterectomy which, in previous studies, has been shown to be highly predictive of carotid thrombosis. The authors' experience to date suggests that dextran can stop this phase of embolization and prevent progression to complete carotid thrombosis. However, the dose of dextran has to be adjusted in 25 per cent of patients (i.e. blind administration of dextran may not be effective) and, very rarely, embolization may recur later.

A review of NSAID complications: gastrointestinal and more

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely prescribed medications in the world. Their use is associated with significant morbidity, commonly including gastrointestinal, renal, and hepatic effects. Other less common effects include otic, central nervous system (CNS), ophthalmic, allergic, and dermatologic effects. Recognizing and diagnosing potential complications are imperative to obtain favorable outcomes in patients on NSAIDs. Among the NSAIDs currently on the market, there exists a wide variability of incidence of organ-specific side effects. Some of these side effects are class specific, but most are not. Much research also is being performed in the field of COX-2-specific inhibitory agents, which would theoretically reduce the gastrointestinal insult of these drugs. Patient awareness through education is crucial in decreasing morbidity and preventing the adverse effects of these drugs.

Self-regulating childhood asthma: a developmental model of family change

This article tests a model of self-regulatory development in which families' cognitive beliefs and behavioral skills for managing asthma symptoms emerge in four successive phases: asthma symptom avoidance, asthma acceptance, asthma compliance, and asthma self-regulation. Confirmatory factor analyses revealed that the hypothesized multiphase model provided the best factorial fit for phase items. Subsequent Guttman analyses of the families' phase scores revealed a high degree of sequential ordering. Finally, trend analyses of family phase differences revealed a significant negative linear relation with measures of asthma severity and a significant positive linear relation with physician care and concern measures, asthma regulatory measures, and beliefs in Western biomedical practices. Despite receiving primary care for asthma at a major metropolitan university hospital, 83% of the sample were classified as precompliant. The phase model of asthma self-regulatory development offers a qualitative approach for investigating the psychological determinants of asthma self-regulatory behavior.

Validation of antroduodenal motility measurements made by echo-planar magnetic resonance imaging

Echo planar imaging, a development of magnetic resonance imaging, can produce snapshot images of the stomach and antroduodenal segment in as little as 64 msec and can be more useful than conventional techniques when assessing motility. The aim of this study was to compare antroduodenal motility measured by simultaneous perfused tube manometry and echo planar imaging. Ten volunteers were studied following the ingestion of 500 mL water or 500 mL porridge. Antroduodenal images, with acquisition times of 130 msec, were taken at 3-sec intervals, synchronized with motility traces and presented as a split-screen video. This allowed direct visual comparison of gastric wall movement and motility to be made. Contractions were confined to either the stomach or the duodenum or propagated across the antroduodenal segment. Over 4550 images were available for analysis. A larger number of propagated contractions were recorded with echo planar imaging in both water (P = 0.03) and food (P = 0.02) groups, whereas manometry detected a greater number of isolated duodenal pressure waves (P = 0.005). The contraction rate for water and food studies was similar, but direct visualization indicated that the manometric technique under-detected propagated events. The ability of echo planar imaging to record antroduodenal contractile activity provides a new insight into the role of occlusive and nonocclusive contractions during gastric emptying.

The Bone Tie. A new device for interfragmentary fixation

A new method of bone fixation is described, using a small stainless steel device to provide compression between fragments with a single drill hole. The Bone Tie uses an old architectural principle to hold bone fragments together with minimal surgical dissection for access. The technique has been used in 14 cases, and the results are presented. In ten cases the outcome was good. Complications were encountered in four, mostly through technical error, although the final outcomes were acceptable.