On the role of energy barriers in determining contact angle hysteresis

The thermodynamic model of contact angles on rough, heterogeneous surfaces developed by Long et al. [J. Long, M.N. Hyder, R.Y.M. Huang and P. Chen, Adv. Colloid Interface Sci. 118 (2005) 173] was employed to study the role of energy barriers in determining contact angle hysteresis. Major energy barriers corresponding to metastable states and minor energy barriers corresponding to secondary metastable states were defined. Distributions of major and/or minor energy barriers as a function of apparent contact angle for various surfaces were obtained. The reproducibility of contact angle measurement, the effect of vibrational energy on contact angle hysteresis and the "stick-slip" phenomenon were discussed. Quantitative relations between contact angles and vibrational energy were obtained. It was found that receding contact angles are normally poorly reproducible for hydrophilic surfaces, but for extremely hydrophobic surfaces, advancing contact angles may have a poor reproducibility. When the vibrational energy available to a system increases, the measured advancing contact angle will decrease while the receding angle will increase until both reach a common value: the system equilibrium angle. This finding not only agrees well with the experimental observations in system equilibrium contact angle measurements, but also lays a theoretical foundation for such measurements. A small vibrational energy may result in a "stick-slip" phenomenon.

Probing colloidal forces between a Si3N4 AFM tip and single nanoparticles of silica and alumina

The atomic force microscope (AFM) has been used to measure surface forces between silicon nitride AFM tips and individual nanoparticles deposited on substrates in 10(-4) and 10(-2) M KCl solutions. Silica nanoparticles (10 nm diameter) were deposited on an alumina substrate and alumina particles (5 to 80 nm diameter) were deposited on a mica substrate using aqueous suspensions. Ionic concentrations and pH were used to manage attractive substrate-particle electrostatic forces. The AFM tip was located on deposited nanoparticles using an operator controlled offset to achieve stepwise tip movements. Nanoparticles were found to have a negligible effect on long-range tip-substrate interactions, however, the forces between the tip and nanoparticle were detectable at small separations. Exponentially increasing short-range repulsive forces, attributed to the hydration forces, were observed for silica nanoparticles. The effective range of hydration forces was found to be 2-3 nm with the decay length of 0.8-1.3 nm. These parameters are in a good agreement with the results reported for macroscopic surfaces of silica obtained using the surface force apparatus suggesting that hydration forces for the silica nanoparticles are similar to those for flat silica surfaces. Hydration forces were not observed for either alumina substrates or alumina nanoparticles in both 10(-4) M KCl solution at pH 6.5 and 10(-2) M KCl at pH 10.2. Instead, strong attractive forces between the silicon nitride tip and the alumina (nanoparticles and substrate) were observed.

p62 mutations, ubiquitin recognition and Paget's disease of bone

Functional analyses of PDB (Paget's disease of bone)-associated mutants of the p62 [also known as SQSTM1 (sequestosome 1)] signalling adaptor protein represent an interesting paradigm for understanding not only the disease mechanism in this skeletal disorder, but also the critical determinants of ubiquitin recognition by an ubiquitin-binding protein. The 11 separate PDB mutations identified to date all affect the C-terminal region of p62 containing the UBA domain (ubiquitin-associated domain), a ubiquitin-binding element. All of these mutations have deleterious effects on ubiquitin binding by p62 in vitro, and there is evidence of an inverse relationship between ubiquitin-binding function and disease severity. The effects on ubiquitin-binding function of most of the mutations can be attributed to either reduced UBA domain stability, and/or the mutations affecting the presumed ubiquitin-binding interface of the UBA domain. However, a subset of the mutations are more difficult to rationalize; several of these affect sequences of p62 outside of the minimal ubiquitin-binding region, providing insights into non-UBA domain sequences within the host protein which mediate ubiquitin-binding affinity. The p62 mutations are presumed to result in activation of (osteoclast) NF-κB (nuclear factor κB) signalling. Understanding how loss of ubiquitin-binding function of p62 impacts on signal transduction events in osteoclasts will undoubtedly further our understanding of the disease mechanism in PDB at the molecular level.

HIV infection among heroin users and area of residence

The aim of this study was to develop a hypothesis to explain the link between HIV prevalence and area of residence. The study was conducted in two parts using two existing data sources. In Part 1, the bloodborne viral test status and test results of a sample of clients attending treatment in December 2001 in two areas of Dublin, an inner city area (Dublin 8) and a suburban area (Dublin 24), were extracted from the Bloodborne Viral Status Dataset created by Grogan. In Part 2 the characteristics of heroin users seeking treatment for the first time at treatment services in their respective areas of residence, Dublin 8 or Dublin 24, between 1997 and 2000 were examined, using data from the National Drug Treatment Reporting System. A higher proportion of heroin users in Dublin 8 had HIV and hepatitis C than did their counterparts in Dublin 24. The analysis suggests that heroin users in Dublin 8 were more likely both to have ever used cocaine and to have used heroin daily, than were those who lived in Dublin 24. Also, a higher proportion of injectors living in Dublin 8 used heroin and cocaine concurrently than did their counterparts in Dublin 24. In both samples, heroin users who lived in Dublin 8 were older than those who lived in Dublin 24. The findings led to a hypothesis:'The risk of acquiring HIV is associated with area of residence and may be linked to cocaine use.

AFM colloidal forces measured between microscopic probes and flat substrates in nanoparticle suspensions

Colloidal forces between atomic force microscopy probes of 0.12 and 0.58 N/m spring constant and flat substrates in nanoparticle suspensions were measured. Silicon nitride tips and glass spheres with a diameter of 5 and 15 mum were used as the probes whereas mica and silicon wafer were used as substrates. Aqueous suspensions were made of 5-80 nm alumina and 10 nm silica particles. Oscillatory force profiles were obtained using atomic force microscope. This finding indicates that the nanoparticles remain to be stratified in the intervening liquid films between the probe and substrate during the force measurements. Such structural effects were manifested for systems featuring attractive and weak repulsive interactions of nanoparticles with the probe and substrate. Oscillation of the structural forces shows a periodicity close to the size of nanoparticles in the suspension. When the nanoparticles are oppositely charged to the probes, they tend to coat the probes and hinder probe-substrate contact.

Completeness and accuracy of the drug treatment reporting system in Dublin, Ireland

BACKGROUND

The National Drug Treatment Reporting System (NDTRS) is the Irish treated-drug misuse surveillance system.

AIM

To measure completeness and accuracy of the NDTRS.

METHODS

Cross-sectional survey of clinical records and matching NDTRS reporting forms of a random sample of 520 clients attending 4 Dublin treatment centres. Using clients' clinical records as the gold standard, system completeness (proportion of sample reported to the NDTRS) and accuracy of selected variables (proportion of reported clients' information on the NDTRS that matched clinical record information) were measured.

RESULTS

452/520 (87%) selected records were retrieved. The NDTRS was only 61.1% (95% CI 56.5-65-5) complete; completeness differed across treatment centres (21.8%-85.6%, p < 0.0001) and was greater for new and returning clients than for continuing clients (81.7% versus 53.9% respectively, p < 0.0001). Problems were identified with the accuracy of some key variables.

CONCLUSIONS

Urgent actions have been taken to improve the completeness and accuracy of the reporting system.

304 TREATMENT OF BOAR SPERM WITH RESPIRATION INHIBITOR MENADIONE: EFFECTS ON MOTILITY, REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIAL TRANSMEMBRANE POTENTIAL (MMP), AND ATP CONTENT

Previously we found that live, fresh or thawed boar sperm show little tendency to accumulate ROS spontaneously, but live sperm accumulated ROS during a 30-min incubation with xanthine and xanthine oxidase and showed marked reduction in motility. High mitochondrial transmembrane potential (MMP) is required to drive the F0/F1 ATPase responsible for producing ATP in most cell types, and ATP is required for sperm motility. This experiment was conducted to investigate the effects of menadione (disrupter of electron transport at Complex I) on sperm motility, MMP, and ATP content. The incidence of cells with high MMP was determined by measuring the fluorescence of JC-1 aggregates bound to the inner mitochondrial membrane using flow cytometry. Computer-assisted motion analysis was conducted using the IVOS version 12 (Hamilton Thorne Research, Beverly, MA, USA), and ATP (pmoles/106 sperm) was determined using the luciferin-luciferase assay. Sperm from six boars were individually Percoll washed to eliminate seminal plasma and incubated at 40 � 106/mL with 0, 1, 10, or 30 �M menadione for 5, 30, 60, and 120 min at 38�C in a modified Tyrode's medium containing 0.1% polyvinyl alcohol with no bicarbonate or BSA. The formation of ROS was confirmed by measuring the red fluorescence developed by the oxidation of hydroethidine to ethidium using flow cytometry. Whereas the basal level of ethidium fluorescence in the absence of menadione was low (2% ethidium-positive cells at 5 min), 10 and 30 �M menadione increased (P < 0.05) the percentage of ethidium-positive cells to 47 and 87%, respectively, at 30 min. Sperm motility did not decrease significantly (79-83%) during the 120 min incubation with no menadione, but menadione caused a significant dose-related decrease (P < 0.05) over time, with 10 and 30 �M menadione decreasing motility to 60 and 40%, 51 and 7%, and 10 and 1% at 30, 60, and 120 min, respectively. JC-1 aggregate fluorescence intensity decreased (P < 0.05) by 45-60% in a dose-related fashion at 120 min compared to the same doses at 5 min. Sperm viability, as measured by number of propidium iodide negative cells, averaged 93.6% during the incubation and was not significantly affected by treatment. The effect of menadione on ATP content was much less than that on motility or JC-1 fluorescence intensity. Mean ATP content averaged 63 pmoles through 60 min at all menadione doses; at 120 min only 30 �M menadione decreased (P < 0.05) ATP to 43 pmoles, compared to all other treatments. Menadione caused an increase in ROS formation and a decline in MMP, which suggested uncoupling of the respiratory chain and oxidative phosphorylation. However, sperm ATP content was not highly correlated with motility. This suggests that ATP content was maintained by the activity of other intermediary metabolism pathways. The reduction in motility may have been due to a ROS induced lesion in ATP utilization or in the contractile apparatus of the cell.

The restoration of Loch Leven, Scotland, UK

This paper reviews the progress made towards the restoration of Loch Leven, the largest lake in lowland Scotland, over the last 20 years. In particular, the importance of direct regulation and of setting water quality objectives and targets is examined. Various means of engaging with stakeholders and the general public are also considered. Success criteria and catchment management initiatives are described and briefly reviewed.

17 FLOW CYTOMETRY ANALYSIS OF THE TURKEY SPERM GLYCOCALYX: EFFECTS OF NEURAMINIDASE TREATMENT

The surface of all eucaryotic cells consists of a carbohydrate-rich zone known as the glycocalyx which mediates a variety of specific cell-recognition processes, including sperm-egg interactions. Several carbohydrate residues are known to be necessary for poultry sperm to traverse the female reproductive tract and for sperm-egg recognition. Alteration of the sperm glycocalyx during semen storage could adversely impact fertility. Accordingly, the aim of this work was to elucidate the sugar residues existing in the surface of turkey spermatozoa as a first step in understanding the deleterious effects of semen storage on sperm physiology and function. Nine turkey toms were randomly assigned to 1 of 3 groups (3 males/group) and semen was pooled for each group. Seminal plasma was removed and isolated sperm were resuspended in Tris-NaCl buffer at either (1) pH 7.4 for immediate staining with 1 of 16 FITC-conjugated lectins (100 �g/mL; 30 min; 25�C; 100 � 106 cells/mL), or (2) pH 6.0 for neuraminidase treatment (30 min; 37�C; 1 IU/109 cells), followed by washing (700 g, 5 min; 4 times) and lectin staining. The control consisted of sperm cells incubated only in Tris-NaCl buffer. Stained and control samples were washed twice (700 g, 5 min) and counterstained with 12 �M propidium iodide (PI); the green fluorescence intensity of PI-negative cells was assessed using a Coulter EPICS XL-MCL" Flow Cytometer (Beckman Coulter, Inc., Fullerton, CA, USA) and single-parameter histogram analysis (6 replicates). Median fluorescence intensity (MdFI) was used to assess differences in the presence of sugar residues among the control, non-neuraminidase-treated, and neuraminidase-treated samples (Kruskal-Wallis test; Tukey's HSD test in post-hoc comparisons). Lectin staining occurred in the PI-positive subpopulation, or membrane-disrupted cells, of all samples. By contrast, only intact cells were labeled by LPA, ConA, RCA-I, and s-WGA lectins in the non-neuraminidase-treated samples, indicating that only residues of sialic acid, �-mannose/�-glucose, �-galactose, and N-acetylglucosamine oligomers were on the surface. As expected, removal of sialic acid significantly (P < 0.05) decreased the fluorescence intensity of LPA-labeled cells. This treatment significantly (P < 0.05) increased the affinity of ConA, RCA-I, and s-WGA lectins, and exposed sugar residues previously undetected using ECA (N-acetyllactosamine), GNA (�-mannose), GS-I (�-galactose), GS-II (N-acetylglucosamine monomers), LOTUS (�-l-fucose), PNA (�-galactose), SBA (�-N-acetylgalactosamine), and WFA (�-N-acetylgalactosamine) lectins. Low levels of MdFI were observed for cells labeled by JAC (�-galactose), PSA (�-mannose/�-glucose), STA (N-acetylglucosamine polymers) and UEA-I (�-l-fucose) irrespective of neuraminidase treatment (P > 0.05). These observations suggest that (1) the carbohydrate content of turkey sperm glycocalyx is extensively masked by sialic acid molecules, (2) it contains a diversity of sugar residues, and (3) discrimination between intact and damaged cells needs to be done in order to properly identify surface binding.

Thermodynamic modeling of contact angles on rough, heterogeneous surfaces

Theoretical modelling for contact angle hysteresis carried out to date has been mostly limited to several idealized surface configurations, either rough or heterogeneous surfaces. This paper presents a preliminary study on the thermodynamics of contact angles on rough and heterogeneous surfaces by employing the principle of minimum free energy and the concept of liquid front. Based on a two-dimensional regular model surface, a set of relations were obtained, which correlate advancing, receding and system equilibrium contact angles to surface topography, roughness and heterogeneity. It was found that system equilibrium contact angles (theta(ES)) can be expressed as a function of surface roughness factor (delta) and the Cassie contact angle (theta(C)): costheta(ES) = deltacostheta(C). This expression can be reduced to the classical Wenzel equation.: theta(ES) = theta(W) for rough but homogeneous surfaces, and the classical Cassie equation theta(ES) = theta(C) for heterogeneous but smooth surfaces. A non-dimensional parameter called surface feature factor (omega) was proposed to classify surfaces into three categories (types): roughness-dominated, heterogeneity-dominated and mixed-rough-heterogeneous. The prediction of advancing and receding contact angles of a surface is dependent on which category the surface belongs to. The thermodynamic analysis of contact angle hysteresis was further extended from the regular model surface to irregular surfaces; consistent results were obtained. The current model not only agrees well with the models previously studied by other researchers for idealized surfaces, but also explores more possibilities to explain the reported experimental results/observations that most existing theories could not explain.

High-dose chemotherapy and peripheral blood stem cell support in refractory gestational trophoblastic neoplasia

We present retrospectively our experience in the use of high-dose chemotherapy and haematopoietic stem cell support (HSCS) for refractory gestational trophoblastic neoplasia (GTN) in the largest series so far reported. In all, 11 patients have been treated at three Trophoblast Centres between 1993 and 2004. The conditioning regimens comprised either Carbop-EC-T (carboplatin, etoposide, cyclophosphamide, paclitaxel and prednisolone) or CEM (carboplatin, etoposide and melphalan) or ICE (ifosfamide, carboplatin, etoposide). Two patients had complete human chorionic gonadotrophin responses, one for 4 and the other for 12 months. Three patients had partial tumour marker responses for 1–2 months. High-dose chemotherapy and HSCS for GTN is still unproven. Further studies are needed, perhaps in high-risk patients who fail their first salvage treatment.

New Pulsed Cold Neutron Beam Line for Fundamental Nuclear Physics at LANSCE

The NPDGamma collaboration has completed the construction of a pulsed cold neutron beam line on flight path12 at the Los Alamos Neutron Science Center (LANSCE). We describe the new beam line and characteristics of the beam. We report results of the moderator brightness and the guide performance measurements. FP12 has the highest pulsed cold neutron intensity for nuclear physics in the world.

Outcomes following childhood head injury: a population study

OBJECTIVES

To identify outcomes following head injury (HI) among a population of children admitted to one hospital centre and to compare outcomes between different severity groups.

METHODS

A postal follow up of children admitted with HI to one National Health Service Trust, between 1992 and 1998, was carried out. Children were aged 5-15 years at injury (mean 9.8), followed up at a mean of 2.2 years post-injury. Parents of 526 injured children (419 mild, 58 moderate, 49 severe) and 45 controls completed questionnaires. Outcomes were assessed using the King's Outcome Scale for Childhood Head Injury (KOSCHI).

RESULTS

Frequent behavioural, emotional, memory, and attention problems were reported by one third of the severe group, one quarter of the moderate, and 10-18% of the mild. Personality change since HI was reported for 148 children (28%; 21% mild HI, 46% moderate, 69% severe). There was a significant relationship between injury severity and KOSCHI outcomes. Following the HI, 252 (48%) had moderate disability (43% mild HI, 64% moderate, 69% severe), while 270 (51%) made a good recovery (57% mild HI, 36% moderate, 22% severe). There was a significant association between social deprivation and poor outcome (p = 0.002). Only 30% (158) of children received hospital follow up after the HI. All children with severe disability received appropriate follow up, but 64% of children with moderate disability received none. No evidence was found to suggest a threshold of injury severity below which the risk of late sequelae could be safely discounted.

CONCLUSIONS

Children admitted with mild HI may be at risk of poor outcomes, but often do not receive routine hospital follow up. A postal questionnaire combined with the KOSCHI to assess outcomes after HI may be used to identify children who would benefit from clinical assessment. Further research is needed to identify factors that place children with mild HI at risk of late morbidity.

Use of the emergency room in Elliot Lake, a rural community of Northern Ontario, Canada

INTRODUCTION

There is ample documentation that use of hospital emergency facilities for reasons other than urgencies/emergencies results in clogged services in many urban centers. However, little has been published about similar misuse of emergency rooms/departments in rural and remote areas, where the situation is usually compounded by a scarcity of healthcare professionals. In Canada there is a shortage of physicians in rural and remote areas as a consequence of misdistribution (most physicians staying in southern urban centers after residence), and there is a chronic misuse of facilities meant for urgencies/emergencies to cope with primary healthcare needs. We address the problem in Elliot Lake, a rural Northern Ontario community of 12,000 people. The economy of Elliot Lake was based on uranium mining until the mid-1990s, when it drastically changed to become a center for affordable retirement and recreational tourism. As a consequence, at the present time the proportion of seniors in Elliot Lake doubles the Canadian average. Our objectives are to elucidate the demographics of emergency room (ER) clients and the effect of the elderly population; the nature of ER use; the perceived level of urgency of clients versus health professionals; and possible alternatives offered to non-urgent/emergency visits. This is the first study of the kind in Northern Ontario, a region the size of France.

METHODS

The study, conducted in July 2001, used a prospective survey, completed by patients and attending clinicians at the time of a patient's presentation to the ER of St Joseph's General Hospital. This hospital is staffed by family physicians, a nurse practitioner, and registered nurses (RNs). The catchment area population (town plus surrounding areas) of the hospital is approximately 18,000 people. ER clients were interviewed verbally, and the attending health professionals responded to written questionnaires. Demographics were recorded (age, sex, employment and marital status), as was each client's reason for making an ER visit. Clients were asked if they had a family physician and if they had contacted him/her before visiting the ER, and if they would use another agency to address their health problem. Each client's, nurse's, and physician/nurse practitioner's perceived urgency level was recorded on a scale from 1 (non-urgent) to 5 (extremely urgent/life threatening). The attending physician/nurse practitioner and attending nurse were also asked to recommend appropriate alternatives, in their judgment, to each ER visit.

RESULTS

Of a total of 1472 ER cases, 1096 (74.5%) verbal interviews with clients were conducted, as well as 1298 (88.2%) and 1013 (68.8%) questionnaires were completed respectively by attending nurses and physicians/nurse practitioner. The age of the clients was roughly proportional to their cohorts in the catchment area. Males and females were equally represented in the sample. Only 28.8% of the clients contacted their family physicians before visiting the ER, although 80.9% of them had a family physician. The reasons for visiting the ER are mostly typical of a primary care practice in Canada, and ER clients considered 19.4% of their visits non-urgent/non-emergency. In contrast, 45.2% of the physicians/nurse practitioner and 63.7% of the nurses considered the visits non-urgent/non-emergency. To reduce ER misuse, two-thirds of the recommendations by staff were to recruit more family physicians and nurse practitioners, and another one-fifth of the recommendations suggested the creation of a walk-in clinic. Other alternatives, such as the use of a variety of agencies available in town, were minimally recommended by healthcare professionals.

CONCLUSION

The core of the problem identified by this research is that more physicians, nurse practitioners, and other health care professionals are needed in Elliot Lake to provide continuity of care. A new medical school is being created for the region, but the first family physicians from this initiative will only be available in 2012. In the meantime, healthcare professionals may need to take more preventive and educational measures to reduce ER misuse, and the use of other town's agencies, Telehealth, case-management of recurrent clients, and collaboration with local pharmacists need to be maximized. Further research is urgently needed into the effects on health outcomes in rural communities that may result from health services having to function beyond their capacity. Rural health clinicians, communities, researchers, and policy makers must work together to design, implement, and evaluate, both immediate and longer term solutions to the problems identified in this study.

Identification of a mutation associated with erythromycin resistance in Bordetella pertussis: implications for surveillance of antimicrobial resistance

Erythromycin treatment failures and in vitro resistance of Bordetella pertussis have been reported on several occasions in the past few years, but the mechanism of resistance has not been described. One potential mechanism, genetic modification of the erythromycin-binding site on the 23S rRNA of the 50S ribosomal subunit, has been observed in other bacteria. To explore this possibility, we amplified the portion of the 23S rRNA gene encoding the central loop of domain V. DNA sequencing and restriction fragment length polymorphism of the PCR products showed that each of the four erythromycin-resistant B. pertussis strains tested contained an A-to-G transition mutation at position 2058 (Escherichia coli numbering) of the 23S rRNA gene. The mutation was not found in seven erythromycin-susceptible isolates tested. Two of the resistant isolates were heterozygous, containing at least one mutant copy and one wild-type copy of the 23S rRNA gene. These results indicate that erythromycin resistance in these strains is likely due to a mutation of the erythromycin-binding site in the 23S rRNA gene. Identification of the resistance mechanism will facilitate development of molecular susceptibility testing methods that can be used directly on clinical specimens in the absence of an isolate.

Clinical characteristics of 13 solid organ transplant recipients with ganciclovir-resistant cytomegalovirus infection

BACKGROUND

Ganciclovir-resistant (GCV-R) cytomegalovirus (CMV) is now being reported with increasing frequency in solid organ transplant recipients.

OBJECTIVE

To describe the clinical characteristics and outcomes of all solid organ transplant patients with GCV-R CMV seen between 1990 and 2000 at a single center.

METHODS

Patients with clinically suspected GCV resistance had viral isolates subjected to phenotypic analysis by plaque reduction assay, and also genotypic analysis. Medical records of the 13 patients with GCV-R CMV were reviewed for demographic, microbiologic, clinical, and pathologic data.

RESULTS

Thirteen patients were identified, including 5 kidney, 1 heart, and 7 lung transplant recipients. All but one patient (92%) were CMV donor seropositive, recipient negative (D+/R-), and 11/13 (85%) had tissue-invasive CMV. CMV viremia was recurrent in 9/13 (69%); in 2 others, the first CMV episode was fatal. Overall, 9/13 (69%) of patients have died, all of CMV or its complications. Of the 10 who received foscarnet, only one survived. All patients had received GCV-based prophylactic regimens; 8/13 patients (62%) had received CMV hyperimmune globulin (CMVIG) as part of prophylaxis, 6/13 (46%) had received oral ganciclovir, and 5/13 (38%) had received intermittent (3 x/week) IV ganciclovir for prophylaxis.

CONCLUSIONS

GCV-R CMV is associated with CMV D+/R- status, tissue-invasive disease, and high mortality even with foscarnet therapy. Exposure to less than fully therapeutic levels of GCV, in the form of oral or intermittent IV GCV, is common. The use of CMVIG in prophylaxis does not appear to prevent resistance. Further work remains to be done to elucidate the risk factors and optimal mode of prophylaxis and treatment for GCV-R CMV.

Expression and inheritance of the wheat Glu-1DX5 gene in transgenic maize

We have produced transgenic maize plants containing a wheat Glu-1Dx5 gene encoding the high-molecular-weight glutenin subunit 1Dx5. Analysis by SDS-PAGE showed that a protein similar in size to the wheat 1Dx5 subunit accumulates in the endosperm of transgenic maize from four independent transformation events. This protein reacts with a monoclonal antibody specific to the wheat 1Dx5 subunit and was not detected in nontransgenic controls or in pollen, anthers, leaves or embryos of plants grown from seeds expressing this protein in endosperm. Genomic Southern-blot analysis is consistent with results from SDS-PAGE and indicates that the transgene integration sites are complex and are different in the four events studied. Using the presence of this protein as a phenotypic marker, we studied the inheritance of this gene through three sexual generations. Reciprocal crosses with nontransgenic plants and self-pollinations were performed, and the resulting kernels were analyzed for the presence of the 1Dx5 subunit. These data, together with PCR analysis for the transgene, suggest that the transgene is inefficiently transmitted through pollen in all four events.

Prevalence of antibodies to hepatitis B, hepatitis C, and HIV and risk factors in entrants to Irish prisons: a national cross sectional survey

OBJECTIVES

To determine the prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in entrants to Irish prisons and to examine risk factors for infection.

DESIGN

Cross sectional, anonymous survey, with self completed risk factor questionnaire and oral fluid specimen for antibody testing.

SETTING

Five of seven committal prisons in the Republic of Ireland.

PARTICIPANTS

607 of the 718 consecutive prison entrants from 6 April to 1 May 1999.

MAIN OUTCOME MEASURES

Prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in prison entrants, and self reported risk factor status.

RESULTS

Prevalence of antibodies to hepatitis B core antigen was 37/596 (6%; 95% confidence interval 4% to 9%), to hepatitis C virus was 130/596 (22%; 19% to 25%), and to HIV was 12/596 (2%; 1% to 4%). A third of the respondents had never previously been in prison; these had the lowest prevalence of antibodies to hepatitis B core antigen (4/197, 2%), to hepatitis C (6/197, 3%), and to HIV (0/197). In total 29% of respondents (173/593) reported ever injecting drugs, but only 7% (14/197) of those entering prison for the first time reported doing so compared with 40% (157/394) of those previously in prison. Use of injected drugs was the most important predictor of antibodies to hepatitis B core antigen and hepatitis C virus.

CONCLUSIONS

Use of injected drugs and infection with hepatitis C virus are endemic in Irish prisons. A third of prison entrants were committed to prison for the first time. Only a small number of first time entrants were infected with one or more of the viruses. These findings confirm the need for increased infection control and harm reduction measures in Irish prisons.

Triggered electromyographic threshold for accuracy of thoracic pedicle screw placement in a porcine model

STUDY DESIGN

A porcine model of thoracic pedicle screw insertion was used to determine the effect of screw position on triggered electromyographic response.

OBJECTIVE

To develop a model of intraoperative detection of misplaced thoracic pedicle screws.

SUMMARY OF BACKGROUND DATA

Triggered electromyographic stimulation has been a valuable aid in determining appropriate placement of lumbar pedicle screws. The use of pedicle screws is increasing in the thoracic spine. Misplaced thoracic pedicle screws may have significant implications if the spinal cord is injured. This study was an attempt to determine whether the established lumbar model can be used for thoracic pedicle screws.

METHODS

Five 120- to 150-lb domestic pigs had 85 pedicle screws placed bilaterally in the thoracic spine at each level from T6 to T15. Screws were inserted entirely in the pedicle (Group A). After removal of the medial pedicle wall, the screws were reinserted in the pedicle with no neural contact (Group B). The screws were then placed with purposeful contact with the neural elements (Group C). The screws were stimulated, eliciting an electromyographic response in the intercostal muscles for each instrumented level. The type of response noted was classified as either primary (response from appropriate nerve root), secondary (response at different root) or no response (response at different root, no response at appropriate root).

RESULTS

Two hundred fifty responses were recorded. A primary response was noted in 72% of recordings. There was a relatively consistent decrease in the triggered electromyographic response from Group A (mean 4.15 +/- 1.80 mA) to Group C (mean 3.02 +/- 2.53 mA) screws (P = 0.0003). There was little difference in the response obtained from Group A to Group B (mean 4.37 +/- 2.48 mA) screws (P > 0.05). When a primary response was recorded, the mean threshold electromyographic response recorded was significantly lower than recordings with secondary and no response recordings (P < 0.05).

CONCLUSION

Even though there was a consistent decrease between the A and C screws that was more definitively separated when a primary response was elicited, it was not possible to determine a cutoff trigger electromyographic level that would consistently differentiate intraosseous from epidural pedicle screw placement. Furthermore, this method could not differentiate screws clearly in the pedicle from screws with medial pedicle wall breakthrough. A more direct method of spinal cord monitoring must be established to provide the surgeon with early warning of the potential of neural injury in the placement of thoracic pedicle screws.

Short-term sequelae of minor head injury (6 years experience of minor head injury clinic)

PURPOSE

It is known that post-concussive symptoms may persist after mild head injury. However, the majority of those patients are denied follow-up or support. A minor head injury clinic was thus established in North Staffordshire Hospital in 1993 to address these problems.

METHODS

Patients 16-65 years old attending hospital with minor head injury were invited to attend the clinic two weeks after presentation. A specialized brain injury nurse and/or assistant clinical psychologist assessed them. Patients with persistent symptoms were invited to a second assessment four weeks later.

RESULTS

One thousand two hundred and fifty-five patients were invited for first assessment, the most common cause of head injury was assault (454) followed by road traffic accident (334). Six hundred and sixteen patients did not attend the first assessment; most of non-attendees were those who had been assaulted (281). Six hundred and thirty-nine patients attended, (472) were male, their mean age was 33. Forty-three per cent of them had history of recent alcohol intake. One third had had a previous head injury. Although 391 attendees were in regular employment, 219 patients were unable to return to work 2 weeks after discharge (56%), and 49 people were still off sick 6 weeks after the injury. The most common complaints at both assessments were fatigue, headache, dizziness, irritability, sleep disturbances, poor concentration and poor memory in that order.

CONCLUSION

This study shows a significant number of patients with minor head injury still complaining of post concussive symptoms, which may contribute to a delay in return to work. The high incidence of non-attendance among the assaulted victims may indicate that this group needs to be more effectively targeted. Further study to look at the longer-term consequences of minor head injury is required in view of these findings.

Safety of fexofenadine in children treated for seasonal allergic rhinitis

BACKGROUND

The incidence of allergic rhinitis in children is increasing.

OBJECTIVE

To evaluate the safety of fexofenadine HCI in children ages 6 through 11 years for treatment of seasonal allergic rhinitis.

METHODS

Two large, double-blind, randomized, placebo-controlled, parallel studies with identical protocols included patients with a positive skin test to fall allergen(s) and allergic rhinitis symptoms. Patients were randomized to receive fexofenadine 15, 30, or 60 mg or placebo twice daily for 2 weeks after a 1-week placebo lead-in. Safety was evaluated through adverse event reporting, electrocardiograms, and pre- and posttreatment laboratory panels and physical examinations.

RESULTS

A total of 875 patients from both studies were eligible for safety analyses. Ten patients (5 on placebo, 5 on fexofenadine) discontinued because of an adverse event; no event that resulted in discontinuation was judged to be caused by study medication. Incidence of adverse events was similar in active and placebo groups, and did not increase with increasing fexofenadine dose: 36.2% (83 of 229) in the placebo group versus 35.3% (79 of 224), 36.8% (77 of 209), and 34.7% (74 of 213) in the 15, 30, and 60 mg twice-daily fexofenadine groups, respectively. Headache was the most commonly reported adverse event (6.6%, 8.0%, 7.2%, and 9.4% in the placebo, 15, 30, 60 mg twice-daily fexofenadine groups, respectively). Clinical, vital sign, electrocardiogram, and laboratory measures were similar in active and placebo groups. There was no statistically significant mean change from baseline in any electrocardiogram parameter after fexofenadine treatment.

CONCLUSIONS

Fexofenadine, 15, 30, and 60 mg twice daily, was safe and well tolerated in this large pediatric patient population.

Improvement of coronary artery endothelial dysfunction with lipid-lowering therapy: heterogeneity of segmental response and correlation with plasma-oxidized low density lipoprotein

OBJECTIVES

This study assessed coronary artery endothelial function in patients with hypercholesterolemia before and after lipid lowering, using quantitative angiography to examine the acetylcholine (Ach) response along the entire analyzable vessel.

BACKGROUND

Lipid lowering reverses endothelial dysfunction, but whether improvement occurs only in some segments and not others has not been established. Statistical correlation of improvement with specific lipid moieties remains undefined.

METHODS

Quantitative angiography was performed after Ach (10(-6), 10(-5), 10(-4) M) in 29 patients with coronary atherosclerosis before and 18 +/- 5.2 months after lipid-lowering treatment (statins, bile sequestrant resins). Standard lipid moieties and markers of oxidized low density lipoprotein (LDL) (immunoglobulin G and M autoantibody titers to malondialdehyde-LDL, E06 epitope) were measured serially.

RESULTS

Pre-treatment of the vessel diameters at control and with 10(-6)M, 10(-5) M and 10(-4) M Ach were 2.108 +/- 0.085, 2.086 +/- 0.087, 2.069 +/- 0.084 and 1.963 +/- 0.097 mm (M +/- SE), respectively, and increased at follow-up to 2.139 +/- 0.094, 2.119 +/- 0.086, 2.127 +/- 0.084 and 2.080 +/- 0.085 mm (p < 0.0001). Improvement in the most constricted and modest declination in the more dilated segments were observed. Change in the E06 and Apolipoprotein A-1 titers correlated with improved vasomotion (p = 0.027 and 0.005, respectively). The pre- and post-treatment levels of the E06 epitope, as well as the post-treatment IgM autoantibody titer to MDA-low density lipoprotein, also correlated (p < 0.028, < 0.001 and p < 0.004, respectively).

CONCLUSIONS

Drug treatment reverses endothelial dysfunction, but the effect is heterogeneous. Most coronary segments show enhancement, while others show declination of dilation, underscoring the importance of assessing the entire analyzable artery. Improvement in vasomotion correlates most significantly with markers of plasma-oxidized low-density lipoprotein.

Expression of RFG/ELE1alpha/ARA70 in normal and malignant prostatic epithelial cell cultures and lines: regulation by methylation and sex steroids

RET fused gene (RFG)/ELE1alpha/androgen receptor-associated protein 70(ARA70) was first found to be involved in the activation of the RET proto-oncogene in thyroid neoplasm and has recently been shown to be a ligand-dependent transcriptional coregulator for androgen receptor (AR). The functionality of RFG/ELE1alpha/ARA70 remains controversial, and little is known about factors regulating its expression in the prostate. Of significant interest is whether this molecule is involved in prostate carcinogenesis. Using reverse transcriptase-polymerase chain reaction semiquantitation, we compared RFG/ELE1alpha/ARA70 mRNA levels in four prostate cancer cell lines (LNCaP, TSU-Pr1, DU-145, and PC-3) with those found in primary cultures of normal prostatic epithelial cells (PrECs). In addition, we examined the effects of androgen and antiandrogen, estrogen and antiestrogen, and a demethylating agent on RFG/ELE1alpha/ARA70 mRNA expression levels in AR- and AR+ PC-3 cells. Reduced levels of RFG/ELE1alpha/ARA70 message were observed in all four prostate cancer cell lines when compared with normal PrECs in primary cultures. RFG/ELE1alpha/ARA70 mRNA levels in PC-3 cells, which express both estrogen receptor subtypes, were upregulated by 17beta-estradiol and inhibited by the antiestrogen ICI-182780. In PC-3(AR+) cells, which were genetically engineered to express AR, exposure to androgen upregulated RFG/ELE1alpha/ARA70 mRNA expression, whereas treatment with 4-hydroxyflutamide lowered expression of this transcript. Furthermore, treatment of DU-145 cells, which did not express RFG/ELE1alpha/ARA70 transcripts, with a demethylating agent reactivated transcription of this gene. Polymerase chain reaction analyses of monochromosomal human-rodent hybrid panels localized a putative RFG/ELE1alpha/ARA70 isoform on human chromosome 5q31.1-31.2. In summary, we identified sex hormones and DNA hypermethylation as regulators of RFG/ELE1alpha/ARA70 expression in prostate cancer cells. In addition, we found reduced levels of RFG/ELE1alpha/ARA70 expression in prostate cancer cell lines when compared with expression levels in normal PrECs in culture. These findings suggest that RFG/ELE1alpha/ARA70 may be involved prostate carcinogenesis and that it may serve as a key mediator of estrogen-androgen synergism.

Comparison between self-reported hepatitis B, hepatitis C, and HIV antibody status and oral fluid assay results in Irish prisoners

Self-reported hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV infection status was compared with the results of oral fluid assays of antibodies to these viruses in prisoners from nine of the 15 prisons in the Republic of Ireland. A total of 1205 out of 1366 prisoners completed a confidential questionnaire and 1193 provided analysable oral fluid specimens for testing for antibodies to HBV core antigen (anti-HBc), HCV (anti-HCV), and HIV (anti-HIV). The self-reported prevalence of hepatitis infection (hepatitis B: 5%; hepatitis C: 19%) was lower than that derived from oral fluid assays (anti-HBc: 9%; anti-HCV: 37%). The self-reported prevalence of HIV infection was similar to that found by oral fluid assay (2%). Many discrepancies were found between self-reported results and the results of oral fluid assays. Of those who reported being positive for HBV, HCV, or HIV, 48%, 5%, and 58%, respectively, tested negative on the oral fluid assay. Of those who reported a previous negative test result for HBV, HCV, or HIV, 10%, 37%, and 2%, respectively, had positive oral fluid assays. Self-reports of hepatitis and HIV infection status are unreliable and should not be used as a basis for planning preventive and treatment services for prisoners. All prisoners should have the opportunity to be tested for HBV, HCV, and HIV infection.

Ultrasonic tonsillectomy

High-frequency ultrasound is an effective mechanism for cutting and coagulating tissue. It is widely used in laparoscopic surgery and may have advantages in tonsillectomy. Twenty-five consecutive cases of tonsillectomy were performed using an ultrasonic scalpel; these were compared with a similar previous consecutive group performed by conventional cold dissection and monopolar electrocautery. There was no undue primary bleeding in either group and no immediate or late postoperative bleeding. Since adenoidectomy was often performed and the total blood loss in each group was so small, no statistical difference could be determined between the groups. No complications were noted in either group. The ultrasonic scalpel has the potential to produce a bloodless tonsillectomy and less collateral tissue damage and is easy to use. There may be less postoperative pain, although this could not be shown statistically in this retrospective study. Ultrasonic tonsillectomy appears to be a safe, and possibly a superior, method of performing this common operation.

Cerebral venous sinus thrombosis: a clinical study of 23 cases

OBJECTIVE

To describe the etiologies, clinical features and diagnosis of cerebral venous sinus thrombosis.

METHODS

We reviewed the records of 23 patients admitted with a documented diagnosis of cerebral venous sinus thrombosis from 1991 through 1999 in the Beijing Tiantan Hospital.

RESULTS

Infection was the major condition associated with cerebral venous sinus thrombosis. Pseudotumor cerebri syndrome was the most common manifestation, while hemiplegia, seizure and unconsciousness may occur alone or in association. The diagnostic sensitivity of computed tomography (CT), magnetic resonance imaging (MRI) and digital subtract angiography (DSA) were 59%, 86% and 100%, respectively. The sensitivity of MRI with magnetic resonance angiography (MRA) reached 96%.

CONCLUSION

As the clinical findings were found to be nonspecific, CT combined with DSA, or MRI with MRA turns out to be valuable for the early diagnosis of cerebral venous sinus thrombosis.

Prevalence of antibodies to hepatitis B, hepatitis C, and HIV and risk factors in Irish prisoners: results of a national cross sectional survey

OBJECTIVES

To determine the prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in the prison population of the Republic of Ireland and to examine risk factors for infection.

DESIGN

Cross sectional, anonymous, unlinked survey, with self completed risk factor questionnaire and provision of oral fluid specimen for antibody testing.

SETTING

Nine of the 15 prisons in the Republic of Ireland.

PARTICIPANTS

1366 prisoners, of whom 1205 (57 women) participated. In the smaller prisons all prisoners were surveyed, while in the three largest prisons one half of the population was randomly sampled. Three small prisons believed not to have a problem with injecting drug use were excluded.

MAIN OUTCOME MEASURES

Prevalence of antibodies to hepatitis B core antigen, antibodies to hepatitis C virus, and antibodies to HIV. Self reported risk factor status.

RESULTS

Prevalence of antibodies to hepatitis B core antigen was 104/1193 (8.7%; 95% confidence interval 7.2% to 10.5%), to hepatitis C virus, 442/1193 (37%; 34.3% to 39.9%), and to HIV, 24/1193 (2%; 1.3% to 3%). The most important predictor of being positive for hepatitis B and hepatitis C was a history of injecting drug use. Thirty four women (60%) and 474 men (42%) reported ever injecting drugs. A fifth (104) of 501 injecting drug users reported first injecting in prison, and 347 (71%) users reported sharing needles in prison.

CONCLUSIONS

Infection with hepatitis C secondary to use of injected drugs is endemic in Irish prisons. Better access to harm reduction strategies is needed in this environment.

Expression of estrogen receptor (ER)-alpha and ER-beta in normal and malignant prostatic epithelial cells: regulation by methylation and involvement in growth regulation

The aim of the current study is to demonstrate normal and malignant prostatic epithelial cells (PrECs) as targets for receptor-mediated estrogenic and antiestrogenic action. Using an improved protocol, we have successfully isolated and maintained highly enriched populations of normal PrECs from ultrasound-guided peripheral zone biopsies, individually determined to be morphologically normal. Semiquantitative reverse transcription-PCR analyses were used to determine whether transcripts of estrogen receptor (ER)-alpha and those of ER-beta were expressed in our normal PrEC primary cultures, in a commercially available PrEC preparation (PrEC; Clontech), in an immortalized PrEC line established from a benign prostatic hyperplasia specimen (BPH-1), and in three prostatic cancer cell lines (LNCaP, PC-3, and DU145). Expression levels of ER-alpha and ER-beta transcripts were related to those of two estrogen-responsive genes [progesterone receptor (PR) and pS2], at the message levels, to gain insights into the functionality of the ER subtypes in PrECs. Interestingly, only transcripts of ER-beta, but not those of ER-alpha, were found in our primary cultures of normal PrECs, along with both PR and pS2 mRNA. These data strongly suggest that estrogen action was signaled exclusively via ER-beta in normal human PrECs. In contrast, PrEC (Clontech) and BPH-1 cells expressed both ER-alpha and ER-beta transcripts and no PR nor pS2 mRNA in PrEC and only a minimal level of PR mRNA in BPH-1. Among the three prostate cancer cell lines, LNCaP expressed ER-beta mRNA along with transcripts of PR and pS2, DU145 expressed messages of ER-beta and PR, and PC-3 cells exhibited ER-alpha, ER-beta, and pS2 mRNA. Thus, unlike normal PrECs, expression patterns of these genes in malignant PrECs are more variable. Treatment of prostate cancer cells with demethylation agents effectively reactivated the expression of ER-alpha mRNA in LNCaP and DU145 and that of pS2 message in DU145. These findings provide experimental evidence that ER-alpha gene silencing in prostate cancer cells, and perhaps also in normal PrECs, are caused by DNA hypermethylation. To evaluate the potential of using antiestrogens as prostate cancer therapies, we have assessed the growth-inhibitory action of estrogens (estradiol and diethylstilbestrol) and antiestrogens (4-hydroxy-tamoxifen and ICI-182,780) on PC-3 and DU-145 cells. In PC-3 cells, which express both ER subtypes, estrogens as well as antiestrogens are effective inhibitors. In contrast, in DU145 cells, which express only ER-beta, antiestrogens, but not estrogens, are growth inhibitors. By comparison, ICI 182,780 is the more effective cell growth inhibitor. Importantly, the ICI 182,780-induced antiproliferative effects were reversed by cotreatment of DU145 cells with an ER-beta antisense oligonucleotide, hence lending additional support to a central role played by ER-beta in mediating growth-inhibitory action of antiestrogens.

Transforming growth factor beta -inducible independent binding of SMAD to the Smad7 promoter

SMAD proteins can mediate transforming growth factor beta (TGF-beta)-inducible transcriptional responses. Whereas SMAD can recognize specific DNA sequences, it is usually recruited to a promoter through interaction with a DNA-binding partner. In an effort to search for TGF-beta-inducible genes, we used a subtractive screening method and identified human Smad7, which can antagonize TGF-beta signaling and is rapidly up-regulated by TGF-beta. In this report, we show that TGF-beta can stabilize Smad7 mRNA and activate Smad7 transcription. The Smad7 promoter is the first TGF-beta responsive promoter identified in vertebrates that contains the 8-bp palindromic SMAD-binding element (SBE), an optimal binding site previously identified by a PCR-based selection from random oligonucleotides by using recombinant Smad3 and Smad4. We demonstrate that on TGF-beta treatment, endogenous SMAD complex can bind to a Smad7 promoter DNA as short as 14 or 16 bp that contains the 8-bp SBE in gel mobility shift and supershift assays. Our studies provide strong evidence that SMAD proteins can bind to a natural TGF-beta responsive promoter independent of other sequencespecific transcription factors. We further show that, whereas recombinant Smad3 binds to the SBE, endogenous or even transfected Smad3 cannot bind to the SBE in the absence of Smad4. These findings have important implications in the identification of target genes of the TGF-beta/SMAD signaling pathways.

Setting risk priorities: a formal model

This article presents a model designed to capture the major aspects of setting priorities among risks, a common task in government and industry. The model has both design features, under the control of the rankers (e.g., how success is evaluated), and context features, properties of the situations that they are trying to understand (e.g., how quickly uncertainty can be reduced). The model is demonstrated in terms of two extreme ranking strategies. The first, sequential risk ranking, devotes all its resources, in a given period, to learning more about a single risk, and its place in the overall ranking. This strategy characterizes the process for a society (or organization or individual) that throws itself completely into dealing with one risk after another. The other extreme strategy, simultaneous risk ranking, spreads available resources equally across all risks. It characterizes the most methodical of ranking exercises. Given ample ranking resources, simultaneous risk ranking will eventually provide an accurate set of priorities, whereas sequential ranking might never get to some risks. Resource constraints, however, may prevent simultaneous rankers from examining any risk very thoroughly. The model is intended to clarify the nature of ranking tasks, predict the efficacy of alternative strategies, and improve their design.

Rearing experiences and stress-induced plasma cortisol as early risk factors for excessive alcohol consumption in nonhuman primates

BACKGROUND

The purpose of this study was to assess the impact of early rearing and stress-induced rise of plasma cortisol collected during infancy as a biological predictors of adult alcohol consumption in nonhuman primates.

METHODS

Ninety-seven female and male rhesus macaques (Macaca mulatta) were investigated. They were reared for their first 6 months of life either without mothers or other adults but with constant access to same-aged peers (peer-reared), or as controls with their mothers (mother-reared). When subjects reached 6 months of age, they underwent a series of four sequential weeks of 4-day social separations. Blood was drawn 1 and 2 hr after initiation of the 4-day separation periods, and the plasma was assayed for plasma cortisol concentrations. When the subjects were young adults (approximately 50 months of age), they were tested for voluntary intake of alcohol for 1 hr per day, 4 days a week, during a period of 5 to 7 weeks under normal living conditions.

RESULTS

The social separation challenge increased infant plasma cortisol concentrations, with peer-reared subjects exhibiting higher stress-induced cortisol concentrations than mother-reared animals. Subjects that responded to the social separation challenge with high cortisol levels consumed significantly more alcohol per kilogram of body weight as adults than subjects with a low cortisol response to the separation challenge, regardless of rearing condition. In addition, male and peer-reared subjects consumed significantly more alcohol than female and mother-reared subjects, respectively.

CONCLUSIONS

These findings suggest that early rearing experiences, such as adult absence, and high plasma cortisol concentrations early in life after a social separation stressor, are useful psychobiological predictors of future high alcohol consumption among nonhuman primates.

[Bilobate flap applied to the treatment of secondary deformity after cheiloplasty]

Secondary deformity after cheiloplasty was common and 7 cases (4 males, 3 females) were reconstructed with bilobate flap. The patients' age ranged from 16 to 30. Five of them with single cleftlip. The deformity of them included loose and shortening of the upperlip, scar, vermilion pitting, too large nostril etc. Lateral tissue of cleftlip was used to construct the bilobate flap which was applied to repairing secondary deformity after cheiloplasty. The method was matched with the principle of anatomy, and the effects were satisfactory.

LC-MS-MS determination of exemestane in human plasma with heated nebulizer interface following solid-phase extraction in the 96 well plate format

A sensitive, specific and rapid analytical method for the quantitation of exemestane (EXE) in human plasma has been developed. EXE, 6-methylen-androsta-1,4-diene-3,17-dione, is an orally active irreversible steroidal aromatase inhibitor used for the therapy of metastatic postmenopausal breast cancer, with estrogen-dependent pathological conditions. The method involves extraction of EXE from human plasma by solid phase extraction using C2 endcapped sorbent in the 96 well plate format (50 mg/2 ml). After conditioning of the sorbent with 1 ml of acetonitrile (x2) the plates were rinsed with 1 ml of water (x2). The prepared samples (0.5 ml plasma, spiked with [13C3] EXE as internal standard (IS) and diluted with 0.5 ml water) were loaded and drawn through the plate with a minimum of vacuum. The plates were then washed with 1 ml acetonitrile:water (10:90) followed by a drying step for 30 min at full vacuum. Elution was by 0.15 ml of 0.1% trifluoracetic acid in acetonitrile (x2) under a minimum of vacuum. Aliquots of 80 microl were finally injected into the LC-MS-MS system. A Zorbax SB C8 column (4.6 x 150 mm, 5 microm) was used to perform the chromatographic separation; the mobile phase was 100% acetonitrile. MS detection used the heated nebulizer interface, with multiple reaction monitoring (MRM) (297-->121 m/z for EXE and 300-->123 m/z for IS) operated in positive ion mode. A weighed linear regression analysis (weighing factor 1/x2) was used to calculate EXE concentration in standard and unknown samples. The method was fully validated in the concentration range 0.05-25 ng ml(-1).

The long form of the leptin receptor (OB-Rb) is widely expressed in the human brain

Leptin exerts important effects on the regulation of food intake and energy expenditure by acting in the brain. Leptin action is mediated by the interaction with a receptor that is alternatively spliced, resulting in at least five different isoforms. The long form (OB-Rb) has a long intracellular domain that is essential for intracellular signal transduction. The specific aim of this study was to further investigate the role that the brain may play in the pathogenesis of obesity in humans. We studied the expression of OB-R mRNA (both short or common and long isoforms) in the brains of obese, lean and diabetic subjects, by in situ hybridization, semiquantitative RT-PCR and Northern blots analysis. We used two alternative probes: one that recognizes all known splice variants (OB-Ra) and a second that recognizes only the long form, OB-Rb. Several brain regions, including hypothalamus, cerebellum, neocortex, entorrhinal cortex, amygdala, and rostral medulla, were evaluated. In situ hybridization studies revealed that both OB-Ra and OB-Rb mRNAs are widely distributed in the human brain. The specific hybridization signal with both probes was detected exclusively in the cytoplasm of the cell body, dendrites and proximal axons of neurons. Hypothalamic nuclei, Purkinje cells and dentate nuclei of the cerebellum, inferior olivary and cranial nerves nuclei in the medulla, amygdala and neurons from both neocortex and entorrhinal cortex demonstrated positive signals. The hybridization signal obtained in ependyma was lower than that in neurons and no specific hybridization was detected in glial cells. No significant differences were identified among the regions or among the three groups studied. These results match those previously obtained by us [Couce et al.: Neuroendocrinology 1997;66:145] in which the distribution of the OB-R protein in the human brain was first described. RT-PCR indicated that the OB-Rb was highly expressed in the hypothalamus and cerebellum. No significant differences of OB-Ra or OB-Rb mRNA expression were identified in lean or obese individuals in these two cerebral regions. The levels of OB-Rb were significantly higher in cerebellum compared to hypothalamus in lean and obese individuals. The original hypothesis that OB-Rb is present only in the hypothalamus needs to be reconsidered. This OB-Rb isoform seems to be widely expressed in the human brain with highest levels in the cerebellum. Obesity and hyperleptinemia appears not to be associated with down-regulation of the OB-Rb in the human brain.