Incidence of PTLD in pediatric renal transplant recipients receiving basiliximab, calcineurin inhibitor, sirolimus and steroids

Pediatric renal transplant recipients were enrolled in a multicenter, randomized, double-blind trial of steroid withdrawal. Subjects received basiliximab, calcineurin inhibitor, sirolimus and steroids. Of 274 subjects enrolled, 19 (6.9%) subjects developed posttransplant lymphoproliferative disorder (PTLD). The relative hazard (RH) for PTLD was 5.3-fold higher in children aged < or =5 versus those >12 years (p = 0.0017). EBV seronegative subjects had a 4.7-fold higher RH compared to EBV positive subjects (p = 0.02). Among EBV donor+/recipient- (D+/R-) subjects, the RH increased by 6.1-fold (p = 0.0001). In a multivariate model, risk factors included recipient age < or =5 years (RH 3.2, 95% CI: 1.1-9.6, p = 0.034) and EBV D+/R- status (RH 7.7, 95% CI: 1.6-35.9, p = 0.010). Of 19 patients with PTLD, 17 are alive with functioning grafts and 2 lost their grafts, 1 of whom subsequently died of recurrent PTLD. This 'robust' immunosuppression protocol was associated with low rejection rates but an unacceptably high incidence of PTLD. The combination of basiliximab, calcineurin inhibitor, sirolimus and steroids resulted in over-immunosuppression in a high-risk pediatric population and we do not recommend its use. Future studies must include routine viral monitoring to permit early identification of viral activity and a protocol driven reduction of immunosuppression aimed at avoiding complications.

Cod liver oil (n-3 fatty acids) as an non-steroidal anti-inflammatory drug sparing agent in rheumatoid arthritis

OBJECTIVES

Dose-dependant gastrointestinal and cardiovascular side-effects limit the use of NSAIDs in the management of RA. The n-3 essential fatty acids (EFAs) have previously demonstrated some anti-inflammatory and NSAID-sparing properties. The objective of this study was to determine whether cod liver oil supplementation helps reduce daily NSAID requirement of patients with RA.

METHODS

Dual-centre, double-blind placebo-controlled randomized study of 9 months' duration. Ninety-seven patients with RA were randomized to take either 10 g of cod liver oil containing 2.2 g of n-3 EFAs or air-filled identical placebo capsules. Documentation of NSAID daily requirement, clinical and laboratory parameters of RA disease activity and safety checks were done at 0, 4, 12, 24 and 36 weeks. At 12 weeks, patients were instructed to gradually reduce, and if possible, stop their NSAID intake. Relative reduction of daily NSAID requirement by >30% after 9 months was the primary outcome measure.

RESULTS

Fifty-eight patients (60%) completed the study. Out of 49 patients 19 (39%) in the cod liver oil group and out of 48 patients 5 (10%) in the placebo group were able to reduce their daily NSAID requirement by >30% (P = 0.002, chi-squared test). No differences between the groups were observed in the clinical parameters of RA disease activity or in the side-effects observed.

CONCLUSIONS

This study suggests that cod liver oil supplements containing n-3 fatty acids can be used as NSAID-sparing agents in RA patients.

Differential roles of CD36, ICAM-1, and P-selectin in Plasmodium falciparum cytoadherence in vivo

Cytoadherence of Plasmodium falciparum-infected red blood cells (IRBCs) on human microvascular endothelium is mediated by synergistic adhesive interactions with different adhesion molecules in vitro. Here, the authors used a unique human/severe combined immunodeficient (SCID) mouse chimeric model to directly visualize IRBC-endothelial interactions in an intact human microvasculature in vivo. Stimulation of human skin grafts with 100 ng TNF-alpha for 4 h led to a dramatic reduction in the distance rolled by IRBCs before arrest, so that the majority of IRBCs adhered directly to the endothelium with a 1.8-fold increase in the number of adherent cells. The decrease in rolling distance and increase in adhesion could be reversed by anti-ICAM-1. More importantly, the effect of TNF-alpha could be seen only in the presence of CD36. A further increase in adhesion by 4.9-fold was observed after 24 h of TNF-alpha stimulation. The increase could be reversed by anti-ICAM-1, but not anti-VCAM-1. In histamine-stimulated grafts, the rolling flux fraction and adhesion increased by 2.8- and 1.6-fold, respectively. The increases were attributable to P-selectin as an inhibitory anti-P-selectin antibody abrogated both the increased rolling flux fraction and firm adhesion. These findings indicate that in addition to CD36, ICAM-1, and P-selectin are major contributors to the dynamic process of IRBC adhesion by different mechanisms in vivo.

Multivariate analysis for stormwater quality characteristics identification from different urban surface types in macau

Statistical analysis of stormwater runoff data enables general identification of runoff characteristics. Six catchments with different urban surface type including roofs, roadway, park, and residential/commercial in Macau were selected for sampling and study during the period from June 2005 to September 2006. Based on univariate statistical analysis of data sampled, major pollutants discharged from different urban surface type were identified. As for iron roof runoff, Zn is the most significant pollutant. The major pollutants from urban roadway runoff are TSS and COD. Stormwater runoff from commercial/residential and Park catchments show high level of COD, TN, and TP concentration. Principal component analysis was further done for identification of linkages between stormwater quality and urban surface types. Two potential pollution sources were identified for study catchments with different urban surface types. The first one is referred as nutrients losses, soil losses and organic pollutants discharges, the second is related to heavy metals losses. PCA was proved to be a viable tool to explain the type of pollution sources and its mechanism for different urban surface type catchments.

Achieving good standards in health promoting schools: Preliminary analysis one year after the implementation of the Hong Kong Healthy Schools Award scheme

BACKGROUND

Improving health literacy can be a strategy for the achievement of public health goals, and the concept of the Health Promoting School can help to build on the health literacy of students. The Centre for Health Education and Health Promotion of The Chinese University of Hong Kong launched the Hong Kong Healthy Schools Award (HKHSA) in 2001. This paper reports the results for the ten secondary schools that underwent assessment in 2002.

METHODS

Based on the overall score for each school, cluster analysis was performed. Each cluster of schools reflected different levels of HKHSA achievement.

RESULTS

This study has shown that those schools reaching high Health Promoting School standards have adopted the concept of a whole school approach in addressing health and social issues, rather than topic-based and school-located health promotion. The schools performing less satisfactorily mainly follow a prescriptive approach.

CONCLUSIONS

These results are a good source of reference for other schools in their Health Promoting Schools programmes.

High rate of discordance between clinical and autopsy diagnoses in blood and marrow transplantation

We analyzed autopsies performed in a Canadian blood and marrow transplantation (BMT) program. We aimed to assess variables that predict the performance of an autopsy, whether rates of autopsy are changing, and the rate of discordance between clinical and autopsy diagnoses. All deceased adult patients from January 1990 to December 2004 were reviewed. Autopsy rates were compared to a large teaching hospital. Of 476 myeloablative BMT patients, 225 died and 48 (27%) underwent autopsy. Autopsy was more likely in patients dying: <100 days post-BMT, in the intensive care unit, after allografting, and on weekends. Autopsy rates among BMT patients declined during the three time periods (1990-1994, 1995-1999, 2000-2004). The autopsy rate at the teaching hospital showed a similar downward temporal trend. Major and minor disagreements at autopsy were present in 16 (34%) and 14 (30%) of cases, respectively. There was no change in discordance rates over time. Thus, despite advances in diagnostic procedures, high levels of disagreement between clinical and autopsy diagnoses for BMT patients persist as autopsy rates decline. We recommend that the autopsy regains its role as a valuable investigation. This may become especially relevant in an era where patients with medical comorbidities are undergoing reduced-intensity BMT.

Src-family kinase dependent disruption of endothelial barrier function by Plasmodium falciparum merozoite proteins

Pulmonary complication in severe Plasmodium falciparum malaria is manifested as a prolonged impairment of gas transfer or the more severe acute respiratory distress syndrome (ARDS). In either clinical presentation, vascular permeability is a major component of the pathologic process. In this report, we examined the effect of clinical P falciparum isolates on barrier function of primary dermal and lung microvascular endothelium in vitro. We showed that parasite sonicates but not intact infected erythrocytes disrupted endothelial barrier function in a Src-family kinase-dependent manner. The abnormalities were manifested both as discontinuous immunofluorescence staining of the junctional proteins ZO-1, claudin 5, and VE-cadherin and the formation of interendothelial gaps in monolayers. These changes were associated with a loss in total protein content of claudin 5 and redistribution of ZO-1 from the cytoskeleton to the membrane and the cytosolic and nuclear fractions. There was minimal evidence of a proinflammatory response or direct cellular cytotoxicity or cell death. The active component in sonicates appeared to be a merozoite-associated protein. Increased permeability was also induced by P falciparum glycophosphatidylinositols (GPIs) and food vacuoles. These results demonstrate that parasite components can alter endothelial barrier function and thus contribute to the pathogenesis of severe falciparum malaria.

Levamisole Inhibits Sequestration of Infected Red Blood Cells in Patients with Falciparum Malaria

BACKGROUND

Sequestration of infected red blood cells (iRBCs) in the microcirculation is central to the pathophysiology of falciparum malaria. It is caused by cytoadhesion of iRBCs to vascular endothelium, mediated through the binding of Plasmodium falciparum erythrocyte membrane protein-1 to several endothelial receptors. Binding to CD36, the major vascular receptor, is stabilized through dephosphorylation of CD36 by an alkaline phosphatase. This is inhibited by the alkaline phosphatase-inhibitor levamisole, resulting in decreased cytoadhesion.

METHODS

Patients with uncomplicated falciparum malaria were randomized to receive either quinine treatment alone or treatment with a single 150-mg dose of levamisole as an adjunct to quinine. Peripheral blood parasitemia and parasite stage distribution were monitored closely over time.

RESULTS

Compared with those in control subjects, peripheral blood parasitemias of mature P. falciparum parasites increased during the 24 h after levamisole administration (n=21; P=.006). The sequestration ratio (between observed and expected peripheral blood parasitemia) of early trophozoite and midtrophozoite parasites increased after levamisole treatment, with near complete prevention of early trophozoite sequestration and >65% prevention of midtrophozoite sequestration.

CONCLUSION

These findings strongly suggest that levamisole decreases iRBC sequestration in falciparum malaria in vivo and should be considered as a potential adjunctive treatment for severe falciparum malaria.

TRIAL REGISTRATION

Current Controlled Trials identifier: 15314870.

Comparison of a new modified laparoscopic presacral neurectomy and conventional laparoscopic presacral neurectomy in the treatment of midline dysmenorrhea

OBJECTIVE

To describe a newly modified laparoscopic presacral neurectomy procedure and to evaluate the long-term benefits of the surgery as a treatment for midline dysmenorrhea.

METHOD

Eighty-eight reproductive female patients with midline dysmenorrhea were enrolled in the non-randomized prospective study. There were fifty-five patients in the modified laparoscopic presacral neurectomy (MLPSN) group and thirty-three patients in the conventional laparoscopic presacral neurectomy (LPSN) group. All patients received post-surgery follow-up of more than eight years for evaluation with respect to pain relief, recurrence, and complications.

RESULTS

Upon receipt of surgery, the MLPSN and the LPSN groups both demonstrated a significant decrease (P<0.001) in the mean pain score when compared to the pre-surgery mean pain scores. However, the probability of recurrence during the eight years of follow-up was 81.8% (27 patients) in the LPSN group, compared to 43.6% (24 patients) in the MLPSN group, resulting in a significantly lower long-term recurrence rate in the MLPSN group, compared to the LPSN group (P<0.05). No patients in the MLPSN group had long-term complications and one patient had constipation after surgery in the LPSN group.

CONCLUSION

The modified laparoscopic presacral neurectomy procedure provides an alternative for those patients who suffer intractable midline dysmenorrhea. This surgery is relatively simple and safe and could result in a satisfactory long-term outcome in the intervention of midline dysmenorrhea.

Tissue microarrays characterise the clinical significance of a VEGF-A protein expression signature in gastrointestinal stromal tumours

A tissue microarray analysis of 22 proteins in gastrointestinal stromal tumours (GIST), followed by an unsupervised, hierarchical monothetic cluster statistical analysis of the results, allowed us to detect a vascular endothelial growth factor (VEGF) protein overexpression signature discriminator of prognosis in GIST, and discover novel VEGF-A DNA variants that may have functional significance.

Confidential registration in health services: randomised controlled trial

BACKGROUND

Human rights legislation safeguards the privacy and dignity of patients.

OBJECTIVE

To assess the effectiveness in terms of patient assessed privacy of confidential registration.

DESIGN

Randomised controlled trial.

SETTING

Emergency Department, University Hospital of Wales.

PARTICIPANTS

A total of 302 patients aged over 15 years.

MAIN OUTCOME MEASURES

Binary choices and ordinal visual analogue scores from a validated questionnaire on self reported measures: patient ability and preference to speak to receptionists and disclose confidential information without being overhead and concern about disclosure of items of confidential personal information.

RESULTS

Patients who registered in a screened area felt significantly more able to tell receptionists things they did not want others to hear. Control patients were significantly more concerned than intervention patients that others heard their name, address, date of birth, reason for emergency department attendance, and telephone number, but not their marital status. Overall, intervention patients were less concerned about disclosure of information and that they had been overheard.

CONCLUSIONS

Patients value privacy when they register and are concerned if others can hear them tell receptionists who they are, how to contact them, and why they are there. Confidential registration should be instituted in health services. Confidential registration increased patient privacy and should be instituted in health services.

Ectophosphorylation of CD36 regulates cytoadherence of Plasmodium falciparum to microvascular endothelium under flow conditions

The adhesion of Plasmodium falciparum-infected erythrocytes (IRBCs) to human dermal microvascular endothelial cells (HDMECs) under flow conditions is regulated by a Src family kinase- and alkaline phosphatase (AP)-dependent mechanism. In this study, we showed that the target of the phosphatase activity is the ectodomain of CD36 at threonine-92 (Thr92). Mouse fibroblasts (NIH 3T3 cells) transfected with wild-type CD36 or a mutant protein in which Thr92 was substituted by Ala supported the rolling and adhesion of IRBCs. However, while the Src family kinase inhibitors PP1 and PP2 and the specific AP inhibitor levamisole significantly reduced IRBC adhesion to wild-type CD36 transfectants as with HDMECs, the inhibitors had no effect on IRBC adhesion to the mutant cells. Using a phosphospecific antibody directed at a 12-amino-acid peptide spanning Thr92, we demonstrated directly that CD36 was constitutively phosphorylated and could be dephosphorylated by exogenous AP. Endothelial CD36 was likewise constitutively phosphorylated. The phosphospecific antibody inhibited IRBC adhesion to HDMECs that could be reversed by preincubating the antibody with the phosphorylated but not the nonphosphorylated peptide. Pretreatment of HDMECs with AP abrogated the effect of PP1 on IRBC adhesion. Collectively, these results are consistent with a critical role for CD36 dephosphorylation through Src family kinase activation in regulating IRBC adhesion to vascular endothelium.

Preliminary assessment of the efficacy, tolerability and safety of a cannabis-based medicine (Sativex) in the treatment of pain caused by rheumatoid arthritis

OBJECTIVES

To assess the efficacy of a cannabis-based medicine (CBM) in the treatment of pain due to rheumatoid arthritis (RA).

METHODS

We compared a CBM (Sativex) with placebo in a randomized, double-blind, parallel group study in 58 patients over 5 weeks of treatment. The CBM was administered by oromucosal spray in the evening and assessments were made the following morning. Efficacy outcomes assessed were pain on movement, pain at rest, morning stiffness and sleep quality measured by a numerical rating scale, the Short-Form McGill Pain Questionnaire (SF-MPQ) and the DAS28 measure of disease activity.

RESULTS

Seventy-five patients were screened and 58 met the eligibility criteria. Thirty-one were randomized to the CBM and 27 to placebo. Mean (S.D.) daily dose achieved in the final treatment week was 5.4 (0.84) actuations for the CBM and 5.3 (1.18) for placebo. In comparison with placebo, the CBM produced statistically significant improvements in pain on movement, pain at rest, quality of sleep, DAS28 and the SF-MPQ pain at present component. There was no effect on morning stiffness but baseline scores were low. The large majority of adverse effects were mild or moderate, and there were no adverse effect-related withdrawals or serious adverse effects in the active treatment group.

CONCLUSIONS

In the first ever controlled trial of a CBM in RA, a significant analgesic effect was observed and disease activity was significantly suppressed following Sativex treatment. Whilst the differences are small and variable across the population, they represent benefits of clinical relevance and show the need for more detailed investigation in this indication.

Abnormal display of PfEMP-1 on erythrocytes carrying haemoglobin C may protect against malaria

Haemoglobin C, which carries a glutamate-to-lysine mutation in the beta-globin chain, protects West African children against Plasmodium falciparum malaria. Mechanisms of protection are not established for the heterozygous (haemoglobin AC) or homozygous (haemoglobin CC) states. Here we report a marked effect of haemoglobin C on the cell-surface properties of P. falciparum-infected erythrocytes involved in pathogenesis. Relative to parasite-infected normal erythrocytes (haemoglobin AA), parasitized AC and CC erythrocytes show reduced adhesion to endothelial monolayers expressing CD36 and intercellular adhesion molecule-1 (ICAM-1). They also show impaired rosetting interactions with non-parasitized erythrocytes, and reduced agglutination in the presence of pooled sera from malaria-immune adults. Abnormal cell-surface display of the main variable cytoadherence ligand, PfEMP-1 (P. falciparum erythrocyte membrane protein-1), correlates with these findings. The abnormalities in PfEMP-1 display are associated with markers of erythrocyte senescence, and are greater in CC than in AC erythrocytes. Haemoglobin C might protect against malaria by reducing PfEMP-1-mediated adherence of parasitized erythrocytes, thereby mitigating the effects of their sequestration in the microvasculature.

Attenuation of cytoadherence of Plasmodium falciparum to microvascular endothelium under flow by hemodilution

The cytoadherence of Plasmodium falciparum-infected erythrocytes (IRBCs) to endothelium is mediated by adhesion molecules within the physical constraints of a viscous fluid containing mostly erythrocytes. The volume fraction of erythrocytes (hematocrit) and their physical properties, such as deformability, are important properties of blood that affect cell recruitment to the vascular wall. In the present study, we examined the effect of hematocrit on IRBC rolling and adhesion on human microvascular endothelial cells in a flow chamber system in vitro. We found hematocrit to be a major determinant of IRBC/endothelial cell interactions. There was a 5-fold and 12-fold increase in IRBC rolling and adhesion, respectively, when hematocrit increased from 10% to 30%, as a result of changes in shear rate. Similar effects were seen in the presence of less deformable erythrocytes, serum proteins, and on endothelium stimulated with tumor necrosis factor-alpha. The results indicate that hemorheologic variations are an important determinant of the degree of cytoadherence.

Significance of the Hygiene Charter towards different sectors in Hong Kong

The occurrence of SARS in March 2003 has resulted in an increased interest, worldwide in emerging infectious diseases. The SARS experience provided us a lesson on the importance of promoting hygienic practices among individuals and different working sectors. In Hong Kong, a voluntary organization called the UNITE proposed a Hygiene Charter which aimed at taking hygiene to new levels. This action has been supported by individuals and different sectors including the Personal and Family, Management, Buildings, Catering, Education, Finance and Commercial, Industrial, Medical and Health, Public Transportation, Social Welfare, Sports and Culture and Tourism. As promotion and maintenance of environmental health requires input from different sectors, the signing of the Hygiene Charter provides an opportunity for individuals and the public to show their pledge and commitment to good hygiene practices. As a result, with environment improvement and good infectious disease control measures, prevention of epidemics of infectious diseases is deemed to be possible.

The importance of needs assessment in planning health promoting schools initiatives: comparison of youth risk behaviours of two districts in Hong Kong

A needs assessment is recommended to be carried out before planning resource allocation in a community as it could help to identify the needs of the people. This study illustrated the importance of needs assessment in planning health promoting school initiatives by comparing the results of youth risk behaviours surveys conducted at two districts of Hong Kong, namely Tsuen Wan and North District. The findings indicated that the two districts should prioritize their resources in respect to their urgent needs. A higher proportion of students from Tsuen Wan participated in vigorous exercise regularly in comparison to students from North District. Students from North District consumed more vegetable per week and exhibited less depressive symptoms than students from Tsuen Wan. The availability of data on youth risk behaviours of the two districts would provide information for strategic planning and direct decision-making in youth health programmes.

High-resolution cDNA microarray CGH mapping of genomic imbalances in osteosarcoma using formalin-fixed paraffin-embedded tissue

Formalin-fixed paraffin embedded (FFPE) tumor tissue provides an opportunity to perform retrospective genomic studies of tumors in which chromosomal imbalances are strongly associated with oncogenesis. The application of comparative genomic hybridization (CGH) has led to the rapid accumulation of cytogenetic information on osteosarcoma (OS); however, the limited resolving power of metaphase CGH does not permit precise mapping of imbalances. Array CGH allows quantitative detection and more precise delineation of copy number aberrations in tumors. Unfortunately the high cost and lower density of BACs on available commercial arrays has limited the ability to comprehensively profile copy number changes in tumors such as OS that are recurrently subject to genomic imbalance. In this study a cDNA/EST microarray including 18,980 human cDNAs (which represent all 22 pairs of autosomal chromosomes and chromosome X) was used for CGH analysis of eight OS FFPE. Chromosomes 1, 12, 17, and X harbored the most imbalances. Gain/amplification of X was observed in 4/8 OS, and in keeping with other recent genomic analyses of OS, gain/amplification of 17p11.2 was often accompanied by a distal deletion in the region of the p53 gene. Gain/amplification of the X chromosome was verified using interphase FISH carried out on a subset of OS FFPE sections and OS tissue arrays.

How would schools step up public health measures to control spread of SARS?

The severe acute respiratory syndrome (SARS) is a rapidly progressive, and sometime fatal disease with more than 1800 patients in over a dozen countries in Asia, Europe, and North America (including the United States and Canada) within two months. On 12 March 2003, the World Health Organisation (WHO) issued a global alert about SARS so it became a global challenge. Strengthening the public health measures at schools would protect children as well as providing the students an opportunity to learn about infectious disease control through life event approach. The public health measures at schools include two important components: basic understanding of the disease so schools would put on high alert on caution cases, and the measures to improve environmental hygiene at schools and preventive measures to stop infectious disease transmission. This will help to empower the whole community the readiness to deal with other outbreaks in the future.

Pasteurella multocida toxin as a tool for studying Gq signal transduction

Pasteurella multocida toxin (PMT) stimulates and subsequently uncouples phospholipase C (PLC) signal transduction through its selective action on the Galphaq subunit. This review summarizes what is currently known about the molecular action of PMT on Gq and the resulting cellular effects. Examples are presented illustrating the use of PMT as a powerful tool for dissecting the molecular mechanisms involving pertussis toxin (PT)-insensitive heterotrimeric G proteins.

Anti-adhesive effect of nitric oxide on Plasmodium falciparum cytoadherence under flow

Nitric oxide (NO) is widely known to inhibit platelet and leukocyte adhesion to endothelium through its regulatory effect on adhesion molecule expression. The objective of the present study was to investigate if NO affects the cytoadherence of Plasmodium falciparum-infected erythrocytes (IRBCs) to human microvascular endothelium (HDMECs) under flow conditions in vitro. The effect of endogenous NO was studied using the NO synthase inhibitor L-N(G)-nitro-arginine-methyl-ester (L-NAME). Treatment of HDMECs with 3 mmol/L of L-NAME for 4 hours significantly enhanced IRBC adhesion and the effect could be reversed by an anti-P-selectin but not an anti-VCAM-1 antibody. The effect of exogenous NO on cytoadherence was studied by using the NO donor 3-(2-hydroxy-2-nitroso-1-propylhydrazino)-1-propanamine (PPN). PPN (300 micro mol/L) treatment reduced the number of adherent IRBCs on resting HDMECs by down-regulating basal ICAM-1 expression, and on tumor necrosis factor-alpha-stimulated HDMECs by inhibition of VCAM-1 induction and down-regulation of ICAM-1 expression. The inhibitory effect of PPN on tumor necrosis factor-alpha-induced VCAM-1 expression at 24 hours was evident when the NO donor was added for as short as 2 hours. These findings suggest that NO may be protective against P. falciparum infection by inhibiting cytoadherence, and underscore the therapeutic potential of NO in the treatment of severe falciparum malaria.

Early origin and recent expansion of Plasmodium falciparum

The emergence of virulent Plasmodium falciparum in Africa within the past 6000 years as a result of a cascade of changes in human behavior and mosquito transmission has recently been hypothesized. Here, we provide genetic evidence for a sudden increase in the African malaria parasite population about 10,000 years ago, followed by migration to other regions on the basis of variation in 100 worldwide mitochondrial DNA sequences. However, both the world and some regional populations appear to be older (50,000 to 100,000 years old), suggesting an earlier wave of migration out of Africa, perhaps during the Pleistocene migration of human beings.

Src-family kinase signaling modulates the adhesion of Plasmodium falciparum on human microvascular endothelium under flow

The pathogenicity of Plasmodium falciparum is due to the unique ability of infected erythrocytes (IRBCs) to adhere to vascular endothelium. We investigated whether adhesion of IRBCs to CD36, the major cytoadherence receptor on human dermal microvascular endothelial cells (HDMECs), induces intracellular signaling and regulates adhesion. A recombinant peptide corresponding to the minimal CD36-binding domain from P falciparum erythrocyte membrane protein 1 (PfEMP1), as well as an anti-CD36 monoclonal antibody (mAb) that inhibits IRBC binding, activated the mitogen-activated protein (MAP) kinase pathway that was dependent on Src-family kinase activity. Treatment of HDMECs with a Src-family kinase-selective inhibitor (PP1) inhibited adhesion of IRBCs in a flow-chamber assay by 72% (P <.001). More importantly, Src-family kinase activity was also required for cytoadherence to intact human microvessels in a human/severe combined immunodeficient (SCID) mouse model in vivo. The effect of PP1 could be mimicked by levamisole, a specific alkaline-phosphatase inhibitor. Firm adhesion to PP1-treated endothelium was restored by exogenous alkaline phosphatase. In contrast, inhibition of the extracellular signal-regulated kinase 1/2 (ERK 1/2) and p38 MAP kinase pathways had no immediate effect on IRBC adhesion. These results suggest a novel mechanism for the modulation of cytoadherence under flow conditions through a signaling pathway involving CD36, Src-family kinases, and an ectoalkaline phosphatase. Targeting endothelial ectoalkaline phosphatases and/or signaling molecules may constitute a novel therapeutic strategy against severe falciparum malaria.

Rheumatoid arthritis and macrovascular disease

OBJECTIVE

To measure the extent of subclinical atherosclerosis in patients with rheumatoid arthritis (RA) compared with controls, and to evaluate any potential vascular risk factors.

METHODS

Forty RA patients were compared with an age- and sex-matched control group. Non-invasive vascular tests, i.e. carotid duplex scanning [measuring common carotid artery intima-media thickness (IMT)], ankle-brachial blood pressure index (ABPI) and QT dispersion on ECG (QTD), were performed. Traditional risk factors such as high blood pressure, blood sugar, lipids and steroid usage were assessed.

RESULTS

The average IMT (S.E.) in RA patients was 0.73 (0.03) mm, compared with 0.62 (0.03) mm in the control group (P=0.01, Mann-Whitney). Ten out of 40 RA patients (25%) had an ABPI < 1.0 compared with 1/40 (2.5%) in the control group (P=0.007, Fisher's). QTD was higher in RA patients; mean (S.E.) 55 (2.70) ms compared with 40 (2.50) ms in the control group (P < 0.001, t-test). There were no significant differences in the prevalence of high blood pressure, diabetes or lipid profiles. However, patients on steroids had a higher mean QTD (S.E.): 63.5 (4) compared with 48 (2.7) ms in those patients who had not received long-term steroids (P=0.003, t-test).

CONCLUSION

RA patients have an increased risk of subclinical vascular disease as was shown by a higher prevalence of carotid disease, peripheral arterial disease and increased QTD. Among traditional risk factors we found a history of steroid usage to be one of the potential risk factors.

Recombinant PfEMP1 peptide inhibits and reverses cytoadherence of clinical Plasmodium falciparum isolates in vivo

The parasite ligand Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) and host endothelial receptors represent potential targets for antiadhesive therapy for cytoadherence. In the present study, the major host receptor CD36 was targeted in vitro and in vivo with a recombinant peptide, PpMC-179, corresponding to the minimal CD36-binding domain from the cysteine-rich interdomain region 1 (CIDR1) within the MCvar1 PfEMP1. The in vitro inhibitory effect of PpMC-179 on human dermal microvascular endothelial cells (HDMECs) expressing multiple relevant adhesion molecules was investigated using a parallel-plate flow chamber. Pretreatment of endothelial monolayers with PpMC-179 (2 microM) inhibited the adhesion of infected erythrocytes (IRBCs) from all clinical isolates tested by 84.4% on resting and 62.8% on tumor necrosis factor alpha (TNF-alpha)-stimulated monolayers. Adhesion to stimulated cells was further inhibited (90.4%) when PpMC-179 was administered with an inhibitory anti-intercellular adhesion molecule 1 (ICAM-1) monoclonal antibody 84H10 (5 microg/mL). To determine the in vivo effectiveness of PpMC-179, we used a human/severe combined immunodeficiency (SCID) mouse chimeric model that allowed direct visualization of cytoadherence on intact human microvasculature. In unstimulated skin grafts, PpMC-179 inhibited adhesion by 86.3% and by 84.6% in TNF-alpha-stimulated skin grafts. More importantly, PpMC-179 administration resulted in the detachment of already adherent IRBCs by 80.7% and 83.3% on resting and stimulated skin grafts, respectively. The antiadhesive effect of PpMC-179 was rapid and sustained in vivo for at least 30 minutes. Our data indicate that targeting cytoadhesion in vivo is feasible and may offer a rapid antimalarial therapy.

The Victorian CPAP program: is there a need for additional education and support?

BACKGROUND

The Victorian Continuous Positive Airways Pressure (CPAP) Program provides CPAP services to financially disadvantaged individuals with moderate to severe sleep apnoea.

AIMS

To evaluate health outcomes in patients referred to the pilot program in order to: (i) assess the magnitude of health benefit from treatment in this highly selected population and (ii) identify patient characteristics or factors related to service provision that may influence outcome.

METHODS

We adopted a simple before-after research design. Patients who were referred to the program were recruited from five sleep centres. Questionnaires were administered at baseline and 1 and 3 months after commencing CPAP. Generic and disease-specific quality of life were assessed using the MOS 36-Item Short-form Health Survey and the Sleep Apnoea Quality-of-life Index, respectively. Subjective daytime sleepiness was measured using the Epworth Sleepiness Scale and the Sleep-Wake Activity Inventory.

RESULTS

Of the 68 subjects enrolled in the study, 59 were available for follow up. There were significant improvements in daytime sleepiness (P < 0.0005). Treatment-related symptoms had a negative impact on overall disease-specific quality of life, however there were significant improvements in all other domains of disease-specific quality of life (P < 0.0005). Improvements in generic quality of life were small but statistically significant (P < 0.05). Hospital, disease severity, baseline sleepiness, gender and CPAP-machine type were not predictors of outcome (P > 0.05).

CONCLUSION

This review of the Victorian CPAP Program identified significant improvements in subjective daytime sleepiness and quality of life, despite the negative impact of treatment-related symptoms. Future research should explore whether services can be modified to help reduce the impact of treatment-related side-effects.

Elevated expression of the genes encoding TNF-alpha and thromboxane synthase in leucocytes from patients with systemic sclerosis

OBJECTIVE

To determine the expression of molecular markers of prostanoid/fatty acid signalling in leucocytes of patients with systemic sclerosis (SSc).

METHODS

Gene expression in patient leucocytes was analysed using real-time fluorescence reverse transcriptase polymerase chain reaction for tumour necrosis factor alpha (TNF-alpha), thromboxane synthase (TXAS, CYP5A), prostacyclin synthase (CYP8A), monocyte chemoattractant protein-1 (MCP-1), peroxisome proliferator-activated receptors (PPAR) alpha, delta and gamma, low-density lipoprotein-associated lipoprotein lipase A(2) (LDL-PLA(2)), apolipoprotein E (apoE) and cholesterol 27-hydroxylase (CYP27).

RESULTS

Both TNF-alpha and TXAS showed an increase in mean expression in the diseased group (6.3-fold and 5.6-fold respectively, P<0.0001). These two markers, along with CYP27, PPARgamma and apoE, provided predictive markers for the development of carotid artery disease within the SSc patient population.

CONCLUSION

The elevated levels of TNF-alpha and thromboxane seen in SSc patient sera are paralleled by increases in the expression of the appropriate genes in leucocytes. This method will allow us to screen for a large number of candidate markers of disease in order to increase our understanding of the processes underlying the pathology of SSc.

Measurement variability in sleep disorders medicine: the Victorian experience

BACKGROUND

Surveys of laboratories in North America have documented significant diversity in the working definitions used for reporting respiratory events in sleep studies.

AIM

To assess sources of variability in the measurement of sleep-disordered breathing (as defined by the Apnoea-Hypopnoea Index) between sleep laboratories in Victoria, Australia.

METHODS

A self-complete written questionnaire was constructed following literature review and interviews with staff at three separate sleep laboratories. The survey was sent to all laboratories listed in Victoria by the Australasian Sleep Association. The first part of the survey related to the type of equipment used to record sleep and other variables during overnight polysomnography and the second part related to the definitions and methods used to report results.

RESULTS

Seventeen out of 18 laboratories returned the surveys. There were variations identified in the types of sensors used to measure particular signals. There were also inconsistencies identified in the criteria used to score arousals, apnoeas and hypopnoeas by different laboratories. The variability was greatest for hypopnoea definitions.

CONCLUSIONS

There is considerable variation in the methods used to measure and define sleep-disordered breathing between sleep laboratories in Victoria. The extent to which these variations influence the comparability of reported results between laboratories requires further evaluation. The survey findings may assist the process of developing and implementing local guidelines for the performance and reporting of polysomnography.

Profound differences in leukocyte-endothelial cell responses to lipopolysaccharide versus lipoteichoic acid

We have investigated the effects of LPS from Escherichia coli, lipoteichoic acid (LTA), and peptidoglycan (PepG) from Staphylococcus aureus, and live S. aureus on leukocyte-endothelial interactions in vivo using intravital microscopy to visualize muscle microvasculature. Systemic vs local administration of LPS induced very different responses. Local administration of LPS into muscle induced significant leukocyte rolling, adhesion, and emigration in postcapillary venules at the site of injection. LPS given systemically dramatically dropped circulating leukocyte counts and increased neutrophils in the lung. However, the drop in circulating leukocytes was not associated with leukocyte sequestration to the site of injection (peritoneum) nor to peripheral microvessels in muscles. Unlike LPS, various preparations of LTA had no systemic and very minor local effect on leukocyte-endothelial interactions, even at high doses and for prolonged duration. LPS, but not LTA, potently activated human endothelium to recruit leukocytes under flow conditions in vitro. Endothelial adhesion molecule expression was also increased extensively with LPS, but not LTA. Interestingly, systemic administration of live S. aureus induced leukocyte-endothelial cell responses similar to LPS. PepG was able to induce leukocyte-endothelial interactions in muscle and peritoneum, but had no effect systemically (no increase in neutrophils in lungs and no decrease in circulating neutrophil counts). These results demonstrate that: 1) LPS has potent, but divergent local and systemic effects on leukocyte-endothelial interactions; 2) S. aureus can induce a systemic response similar to LPS, but this response is unlikely to be due to LTA, but more likely to be mediated in part by PepG.

A global emerging disease of Klebsiella pneumoniae liver abscess: is serotype K1 an important factor for complicated endophthalmitis?

BACKGROUND AND AIMS

Over the past two decades in Taiwan, pyogenic liver abscess has usually been caused by a single microorganism, Klebsiella pneumoniae, and is frequently associated with the serious complication of endophthalmitis, especially in diabetic patients. However, the relationship between the clinical presentation and bacterial factors remains unclear. The aim of this study was to investigate the clinical features of patients and the serotype and ribotype of K pneumoniae liver abscess.

METHODS

From July 1991 to June 1998, a total of 134 cases of K pneumoniae liver abscess with 248 K pneumoniae isolates from the same patients were collected from two large medical centres in northern Taiwan. Clinical data were collected from medical records. Serotyping and ribotyping were performed using the countercurrent immunoelectrophoresis method and automated Riboprinter.

RESULTS

Serotyping revealed that the most common serotypes were K1 (63.4%) and K2 (14.2%). K1 isolates occurred at a significantly higher frequency (p<0.01) than all other serotypes. Among 134 patients, 105 (78.4%) had suffered from diabetes mellitus for 3-15 years. Fourteen patients (10.4%) had metastatic infection to the eye causing septic endophthalmitis. Liver aspirates, and blood and vitreous pus cultures yielded the same serotype of K pneumoniae in all patients. Among patients with septic endophthalmitis, 92.3% (13/14) were diabetic, and 85.7% (12/14) of the isolates belonged to serotype K1. For molecular typing, different degrees of genetic polymorphism among isolates with the same K1 serotype suggested no particular prevalence of any one strain in K pneumoniae liver abscess.

CONCLUSION

K pneumoniae serotype K1 was significantly associated with liver abscess and the complication of endophthalmitis, especially in diabetic patients. Physicians should request an immediate report of serotyping and susceptibility test results simultaneously if a diagnosis of pyogenic liver abscess has been made so that early and appropriate management for possible complications will not be delayed. The use of ceftriaxone because of its higher concentration in the aqueous humor is suggested to decrease the chance of septic endophthalmitis.

Factors contributing to hospital readmission in a Hong Kong regional hospital: a case-controlled study

BACKGROUND

As many as 50% of total hospital admissions are readmissions. Because the factors contributing to hospital readmission are multiple, and research findings are not conclusive, it is important for clinicians to gain an understanding of the key factors that contribute to readmission.

OBJECTIVES

This study explores the factors contributing to hospital readmission and derives an explanatory model that can best identify characteristics of patients at high risk for hospital readmission.

METHODS

This research was a case-controlled study with readmitted patients (n = 168) as the readmitted group and non-readmitted patients (n = 98) as the control group. The variables included demographic data, health assessment data, medical diagnosis, frequency of admissions, severity of illness, intensity of service and improvement of condition. The study sample was also interviewed to explore the patients' views on their repeated hospitalization.

RESULTS

In the bivariate analysis significant differences between the study and control groups were multiple and generally consistent with findings in other studies. Using multiple logistic regression, however, the final model shows that only three factors best predict readmissions: frequency (3-4 times) of readmissions (OR = 9.96, p < .0001) and frequency (more than 5 times) of readmissions (OR = 15.73, p < .0001), financial assistance (OR = 5.03, p < .001), and severity of illness (OR = 3.12, p < .01). Our interview data suggest that the readmitted patients required assistance to accomplish daily living activities upon discharge and often returned to the hospital for the same health reason.

CONCLUSION

The study findings suggest that patients who are frequently readmitted to the hospital are severely ill; are on public assistance; and may need special attention when discharged in order to attenuate repeated hospital readmission.

McLeod neuroacanthocytosis: genotype and phenotype

McLeod syndrome is caused by mutations of XK, an X-chromosomal gene of unknown function. Originally defined as a peculiar Kell blood group variant, the disease affects multiple organs, including the nervous system, but is certainly underdiagnosed. We analyzed the mutations and clinical findings of 22 affected men, aged 27 to 72 years. Fifteen different XK mutations were found, nine of which were novel, including the one of the eponymous case McLeod. Their common result is predicted absence or truncation of the XK protein. All patients showed elevated levels of muscle creatine phosphokinase, but clinical myopathy was less common. A peripheral neuropathy with areflexia was found in all but 2 patients. The central nervous system was affected in 15 patients, as obvious from the occurrence of seizures, cognitive impairment, psychopathology, and choreatic movements. Neuroimaging emphasized the particular involvement of the basal ganglia, which was also detected in 1 asymptomatic young patient. Most features develop with age, mainly after the fourth decade. The resemblance of McLeod syndrome with Huntington's disease and with autosomal recessive chorea-acanthocytosis suggests that the corresponding proteins--XK, huntingtin, and chorein--might belong to a common pathway, the dysfunction of which causes degeneration of the basal ganglia.

Effects of nitric oxide and hydrogen peroxide on histamine release from RBL-2H3 cells

We have studied the effect of nitric oxide (NO) and hydrogen peroxide (H(2)O(2)), two reactive oxygen species (ROS) on histamine release (HR) from RBL-2H3 cells, a rat mucosal-type mast cell line. Marked HR was elicited by antigen (DNP-HSA), calcium ionophore A23187, sodium fluoride or phospholipase C, but not with compound 48/80 or 1,2-dioctanoyl-sn-glycerol. The NO-synthase substrate L-arginine and its inactive enantiomer (D-arginine), each on its own, induced a small but significant increase in HR above the basal level. However, the NO-donors (sodium nitroprusside or NaNO(3)) or the NO-synthase inducer lipopolysaccharide did not induce HR. Moreover, methylene blue (MB), which inhibits guanylate cyclase and N(omega)-nitro-L-arginine (L-NA), an inhibitor of NO synthase, were also without effect on either the basal HR or the L-arginine-induced HR. HR induced by A23187, DNP-HSA, sodium fluoride or phospholipase C was markedly reduced by MB, but mildly by L-NA (both at 1-100 microM). H(2)O(2) (0.01-1.0 mM) on its own did not induce HR, but it had a potent inhibitory effect on DNP-HSA- or A23187-induced HR, which was not reversed by L-NA (1-100 microM). Taken together, it seems that neither the stimulatory nor the inhibitory effects of the NO-related compounds on HR can be attributed to NO, but rather to other mechanisms. The inhibition of HR by H(2)O(2) also does not involve NO and suggests a negative feedback regulatory role for the peroxide in the allergic inflammation.

The contribution of renal transplantation to final adult height: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

Final adult height following renal transplantation was assessed in 237 recipients enrolled in NAPRTCS before the ages of 11 (girls) and 12 (boys) years and followed for at least 6 months with a functioning graft at or after 18 years of age. The overall change in standardized height (SDS) from baseline to final adult height (FH) was 0.0; however, delta SDS was significantly better for the youngest recipients (6-8 years) than for the older age group. Retarded FH was associated with higher average prednisone dosage and better FH was associated with good graft function. Low baseline SDS was also predictive of retarded FH. Final adult height continues to be suboptimal in the cyclosporine A era.

Plasmodium falciparum erythrocyte membrane protein 1 functions as a ligand for P-selectin

The malarial protein Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a parasite protein that is exported to the surface of the infected erythrocyte, where it is inserted into the red cell cytoskeleton in the second half of the parasite life cycle. The surface expression of PfEMP1 coincides with the occurrence of the adhesion of infected erythrocytes to vascular endothelium. This protein has been shown to interact with CD36, intercellular adhesion molecule-1 (ICAM-1) and chondroitin sulfate A (CSA). In this study, it is demonstrated by affinity purification and western blot analysis that PfEMP1 also functions as a cell surface ligand for P-selectin, an adhesion molecule that has been shown to mediate the rolling of infected erythrocytes under physiologic flow conditions, leading to a significant increase in adhesion to CD36 on activated platelets and microvascular endothelium.

Emergence of reduced susceptibility and resistance to fluoroquinolones in Escherichia coli in Taiwan and contributions of distinct selective pressures

A survey of 1,203 Escherichia coli isolates from 44 hospitals in Taiwan revealed that 136 (11.3%) isolates were resistant to fluoroquinolones and that another 261 (21.7%) isolates had reduced susceptibility. Resistance was more common in isolates responsible for hospital-acquired (mostly in intensive care units) infections (17.5%) than in other adult inpatient (11.4%; P = 0.08) and outpatient isolates (11.9%; P > 0.1). Similarly, reduced susceptibility was more common in isolates responsible for hospital-acquired infections (30.9%) than in other adult inpatient (21.0%; P = 0.04) and outpatient (21.4%; P = 0.06) isolates. Isolates from pediatric patients were less likely to be resistant (1.3 versus 12.0%; P < 0.01) but were nearly as likely to have reduced susceptibility (17.7 versus 21.9%; P > 0.1) as nonpediatric isolates. There was an inverse relationship in the proportion of isolates that were resistant versus the proportion that had reduced susceptibility among isolates from individual hospitals (R = 0.031; P < 0.05). In an analysis of isolates from two hospitals, all 9 resistant strains possessed double point mutations in gyrA and all 19 strains with reduced susceptibility strains had single point mutations; no mutations were found among fully susceptible strains. Risk factors for resistance included underlying cancer (odds ratio [OR], 83; 95% confidence interval [CI(95)], 7.3 to 2,241; P < 0.001), exposure to a quinolone (OR, undefined; P = 0.02), and exposure to a nonquinolone antibiotic (OR, 20; CI(95), 2.2 to 482; P < 0.001); underlying cancer was the only independent risk factor (OR, 83; CI(95), 8.6 to 807; P < 0.001). There were no significant associations between any of these factors and reduced susceptibility. Whereas acute and chronic quinolone use in cancer patients is a major selective pressure for resistance, other undetermined but distinct selective pressures appear to be more responsible for reduced susceptibility to fluoroquinolones in E. coli.

Increasing resistance of Streptococcus pneumoniae to fluoroquinolones: results of a Hong Kong multicentre study in 2000

The MICs of 13 antimicrobial agents including seven fluoroquinolones (ciprofloxacin, levofloxacin, sparfloxacin, grepafloxacin, gatifloxacin, moxifloxacin and clinafloxacin) for Streptococcus pneumoniae isolates obtained from all regions of Hong Kong in the year 2000 were determined by the Etest. Overall, 39.4% of 180 isolates were susceptible to penicillin, 11.7% were intermediate and 48.9% were resistant. The overall prevalence of fluoroquinolone non-susceptibility (levofloxacin MIC > or = 4 mg/L) was 13.3% but increased to 27.3% among the penicillin-resistant isolates. For the fluoroquinolone non-susceptible isolates, within-class cross-resistance was common. For the fluoroquinolone non-susceptible isolates, the median MICs of clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and grepafloxacin were, respectively, six-, 24-, 32- 84- and 128-fold higher than those for the susceptible isolates. All fluoroquinolone non-susceptible strains were derived from adults. The prevalence of fluoroquinolone resistance was higher in isolates from older patients (17.1% among those > or = 65 years of age versus 9.1% among those 18-64 years of age, P < 0.001) and from adults with chronic obstructive pulmonary disease (24.6% versus 9.3%, P = 0.01). All fluoroquinolone non-susceptible strains were non-susceptible to penicillin (MIC range 2-4 mg/L), cefotaxime (MIC range 1-4 mg/L) and erythromycin (MIC range 4- > or = 256 mg/L). The fluoroquinolone non-susceptible isolates were genetically related to the Spain(23F)-1 clone when analysed by pulse-field gel electrophoresis and multilocus sequence typing. In conclusion, a rapid increase in the prevalence of fluoroquinolone resistance among S. pneumoniae was found in Hong Kong. Typing analysis suggests that this is due to the pan-regional dissemination of a fluoroquinolone-resistant variant (designated Hong Kong(23F)-1) of the globally distributed Spain(23)F-1 clone.

Exclusive neutrophil recruitment with oncostatin M in a human system

Oncostatin M (OSM), a member of the IL-6 family has been postulated to be a potent recruiter of leukocytes, however information regarding the molecular mechanism(s) underlying this event is extremely limited. Therefore, the aim of this study was to investigate the role of OSM-mediated leukocyte recruitment in a human system in vitro under flow conditions. A parallel-plate flow chamber assay was used to examine leukocyte recruitment from whole blood by human umbilical vein endothelium treated for 24 hours with OSM. OSM in a dose-response manner revealed very significant leukocyte rolling and adhesion reaching optimal levels at a very low concentration of OSM (10 ng/ml). The OSM-induced leukocyte rolling and adhesion was comparable to levels seen with tumor necrosis factor. OSM was extremely selective for neutrophil recruitment (96%) with <3% lymphocyte recruitment. By contrast, tumor necrosis factor-alpha revealed no such selectivity, recruiting 70% neutrophils and at least 25% lymphocytes and detectable levels of eosinophils at 24 hours. The molecular mechanism underlying the leukocyte recruitment seemed to be entirely dependent on P-selectin as leukocyte recruitment could be completely blocked by the addition of a P-selectin-blocking antibody. An elevation in both P-selectin message and protein was observed with 24 hours of OSM stimulation of endothelium. By contrast, E-selectin and VCAM-1 were not detectable after OSM stimulation. Similar results were seen with passaged dermal microvascular endothelium that does not have a prestored pool of P-selectin. Based on these results, we conclude that OSM may be a very selective potent recruiter of neutrophils in more prolonged inflammatory conditions, an event exclusively dependent on P-selectin.

In vitro characterization of Ac-RYYRWK-NH(2), Ac-RYYRIK-NH(2) and [Phe1Psi(CH(2)-NH)Gly2] nociceptin(1-13)NH(2) at rat native and recombinant ORL(1) receptors

The pharmacology of ORL(1) compounds, [Phe1Psi(CH(2)-NH)Gly2]nociceptin(1-13)NH(2) (F/GNC13), Ac-RYYRIK-NH(2) and Ac-RYYRWK-NH(2) was evaluated at rat ORL(1) receptors in frontal cortex (CTX), transfected chinese hamster ovary (CHO) cells, vas deferens (VD) and anococcygeus (AC). Ranked affinities for the inhibition of [3H]nociceptin binding to CTX and CHO's were: Ac-RYYRWK-NH(2) identical withAc-RYYRIK-NH(2) identical withnociceptin>F/GNC13>Dynorphin A>naloxone. The full agonist, nociceptin stimulated [35S]GTPgammaS binding in CTX (E(max)=174%) and CHO's (E(max)=311%); all other ORL(1) peptides acted as partial agonists with the following rank order for E(max) values: Ac-RYYRWK-NH(2) (96% (CTX), 202% (CHO))>F/GNC13 (44% (CTX), 136% (CHO)) identical withAc-RYYRIK-NH(2) (44% (CTX), 115% (CHO)). Schild analysis generated pA(2) values in CTX of 8.59 (F/GNC13) and 9.13 (Ac-RYYRIK-NH(2)). cAMP production in CHO's was inhibited by 77% (nociceptin), 58% (Ac-RYYRWK-NH(2)), 55% (F/GNC13) and 49% (Ac-RYYRIK-NH(2)). Nociceptin inhibited electrically evoked contractions in isolated tissues by 95% (VD) and 98% (AC); partial inhibition was observed with Ac-RYYRWK-NH(2) (72% (VD), 66% (AC)) and Ac-RYYRIK-NH(2) (54% (VD); 37%(AC)). Ineffective in the VD, F/GNC13 caused a small inhibition in the AC that was reversed at higher concentrations. Schild analysis gave pA(2) affinities of 7.32(VD) and 7.34(AC) for F/GNC13 and 8.69(AC) for Ac-RYYRIK-NH(2).

Raman spectroscopy of octadecylsilane stationary phase conformational order. Effect of solvent

The effect of solvent on the conformation of alkyl chains of two octadecysilane-based stationary phases is probed using Raman spectroscopy. Spectral data indicate that the alkyl chains of commercially available polymeric and monomeric solid-phase extraction stationary phases are disordered to a varying extent by solvents of different polarity. For the polymeric octadecylsilane stationary phase, the polar solvents water, acetonitrile, methanol, acetone and isopropanol have little impact on the conformational order of the octadecylsilane bonded phase relative to air. However, the alkyl portion of this stationary phase is substantially disordered in the low-polarity solvents tetrahydrofuran, chloroform, benzene, toluene and hexane. The monomeric octadecylsilane stationary phase is less susceptible to disordering by solvents, although more disorder in the less polar solvents is also observed for this system. These results are interpreted in terms of the local surface bonding density and interchain spacing of these two stationary phases, and the ability of the solvent to penetrate the chains as a function of polarity. The results clearly demonstrate the ability of Raman spectroscopy to precisely indicate subtle changes in conformational order of alkylsilane stationary phases.