A case study of the development of a videofluoroscopy service: Integration and collaboration between the speech & language therapy and radiographer teams

BACKGROUND

Videofluoroscopy (VFSS) is a dynamic fluoroscopic examination of swallowing function to assess oropharyngeal dysphagia. In the United Kingdom (UK), this test is typically performed by a team of Speech and Language Therapists (SLTs), radiologists and radiographers. While VFSS is undertaken across the UK, recent literature reflects wide variation in the procedure itself.

OBJECTIVES

The role of the advanced practitioner gastrointestinal (GI) radiographer within a VFSS service will be illustrated by the narrative description of a VFSS service in a large NHS teaching hospital in England. The paper compares the existing VFSS service against recent literature outlining national practice, with particular focus upon the growing role of the advanced practitioner GI radiographer. Existing pressures upon the National Health Service (NHS) are examined as contributing factors. Lastly, further plans to improve the clinic are delineated.

KEY FINDINGS

Recent literature shows a wide national variation in the running of VFSS services. Pertinently, the evidence suggests that radiologists are becoming progressively less involved in these clinics, with a move towards more practitioner-led services. The changes to the described VFSS service are in line with national trends, and the described clinic is an effective example of a practitioner-led service which fully utilises the role of the advanced practitioner GI radiographer.

CONCLUSION

This paper demonstrates that a practitioner-led service can benefit both patients and staff. Further improvement work is ongoing, with a particular need to involve service users and collect more meaningful outcome measures.

IMPLICATIONS FOR PRACTICE

The growing move towards practitioner-led clinics is likely to continue. However, the wide variation in practice nationally and lack of consistent, recognised training that meets the needs of both SLT and radiographers, needs to be addressed.

Aeroallergens in Canada: Distribution, Public Health Impacts, and Opportunities for Prevention

Aeroallergens occur naturally in the environment and are widely dispersed across Canada, yet their public health implications are not well-understood. This review intends to provide a scientific and public health-oriented perspective on aeroallergens in Canada: their distribution, health impacts, and new developments including the effects of climate change and the potential role of aeroallergens in the development of allergies and asthma. The review also describes anthropogenic effects on plant distribution and diversity, and how aeroallergens interact with other environmental elements, such as air pollution and weather events. Increased understanding of the relationships between aeroallergens and health will enhance our ability to provide accurate information, improve preventive measures and provide timely treatments for affected populations.

Perspectives and visions on CO2 capture and utilisation

This article summarises and contextualises the debates which occurred during the Carbon Dioxide Utilisation Faraday Discussion meeting. The utilisation of carbon dioxide is discussed in terms of both conversion to fuel, with a potential impact on atmospheric carbon dioxide levels, and conversion to chemicals with a potential impact on sustainability.

DNA hypomethylation, ambient particulate matter, and increased blood pressure: findings from controlled human exposure experiments

BACKGROUND

Short-term exposures to fine (<2.5 μm aerodynamic diameter) ambient particulate-matter (PM) have been related with increased blood pressure (BP) in controlled-human exposure and community-based studies. However, whether coarse (2.5 to 10 μm) PM exposure increases BP is uncertain. Recent observational studies have linked PM exposures with blood DNA hypomethylation, an epigenetic alteration that activates inflammatory and vascular responses. No experimental evidence is available to confirm those observational data and demonstrate the relations between PM, hypomethylation, and BP.

METHODS AND RESULTS

We conducted a cross-over trial of controlled-human exposure to concentrated ambient particles (CAPs). Fifteen healthy adult participants were exposed for 130 minutes to fine CAPs, coarse CAPs, or HEPA-filtered medical air (control) in randomized order with ≥2-week washout. Repetitive-element (Alu, long interspersed nuclear element-1 [LINE-1]) and candidate-gene (TLR4, IL-12, IL-6, iNOS) blood methylation, systolic and diastolic BP were measured pre- and postexposure. After adjustment for multiple comparisons, fine CAPs exposure lowered Alu methylation (β-standardized=-0.74, adjusted-P=0.03); coarse CAPs exposure lowered TLR4 methylation (β-standardized=-0.27, adjusted-P=0.04). Both fine and coarse CAPs determined significantly increased systolic BP (β=2.53 mm Hg, P=0.001; β=1.56 mm Hg, P=0.03, respectively) and nonsignificantly increased diastolic BP (β=0.98 mm Hg, P=0.12; β=0.82 mm Hg, P=0.11, respectively). Decreased Alu and TLR4 methylation was associated with higher postexposure DBP (β-standardized=0.41, P=0.04; and β-standardized=0.84, P=0.02; respectively). Decreased TLR4 methylation was associated with higher postexposure SBP (β-standardized=1.45, P=0.01).

CONCLUSIONS

Our findings provide novel evidence of effects of coarse PM on BP and confirm effects of fine PM. Our results provide the first experimental evidence of PM-induced DNA hypomethylation and its correlation to BP.

In situ randomised trial investigating abrasive effects of two desensitising toothpastes on dentine with acidic challenge prior to brushing

OBJECTIVES

To determine if brushing dentine with 2 moderate RDA desensitising toothpastes, results in a significant dentine wear difference and whether this difference continues to be relevant when preceded with an erosive challenge.

METHODS

An in situ, single centre, single blind, randomised, split mouth study, evaluated the difference in abrasion of 2 toothpastes (SFM - Sensodyne Fresh Mint(®) RDA 70; CPHM - Crest Pro-Health Clean Mint(®) RDA 120) in 28 healthy volunteers. Two toothpaste treatments were administered 3×/day, for each of the two 15 day periods, subjects wearing bi-lateral, lower buccal appliances each with 4 dentine sections. A 2 min extra-oral acidic challenge preceded toothbrushing for 2 study arms. Contact profilometry measured samples at baseline, days 5, 10 and 15.

RESULTS

Brushing with SFM was significantly less abrasive than brushing with CPHM at all time points, with or without a preceding acidic challenge (p<0.0001). The additional dentine loss arising from the erosive challenge prior to brushing with each paste was linear with time and independent of abrasive effect.

CONCLUSIONS

The desensiting toothpastes' RDA, directly related to dentine loss with toothbrushing. An acidic challenge prior to brushing did not negate the benefits of reduced wear from the lower RDA paste compared to the higher RDA paste. When brushing eroded dentine, the additional wear appeared independent of abrasive effect. Dentine hypersensitivity sufferers should be recommended to use a low-moderate RDA toothpaste, not to brush more than 2×/day and not immediately following an acidic challenge.

Gas insufflation of minimal preparation CT of the colon reduces false-positives

OBJECTIVES

Minimal preparation CT of the colon (MPCT colon) is used for investigation of suspected colorectal cancer in frail and/or elderly patients who would be expected to tolerate laxative bowel preparation poorly. Although it has good sensitivity for colorectal cancer it has a poor specificity. We wished to investigate whether distension of the colon with carbon dioxide alone would reduce the number of false-positives, but without making the test arduous or excessively uncomfortable.

METHODS

134 patients were recruited and underwent MPCT colon with gas insufflation and antispasmodics. Results were compared with a cohort of 134 patients undergoing standard protocol MPCT colon. The numbers of false-positives were compared, as was reader confidence. All trial patients were given a questionnaire documenting their experience.

RESULTS

The number of false-positives was 15% in the control group and 5% in the trial group; this difference was statistically significant, (p=0.01). Reader confidence was increased in the trial group. Patient tolerance was good, with 95% saying they would have the test again.

CONCLUSION

Use of gas insufflation and antispasmodics reduces the false-positives from 15% to 5% without adversely affecting patient tolerance.

Syk associates with clathrin and mediates phosphatidylinositol 3-kinase activation during human rhinovirus internalization

Human rhinovirus (HRV) causes the common cold. The most common acute infection in humans, HRV is a leading cause of exacerbations of asthma and chronic obstruction pulmonary disease because of its ability to exacerbate airway inflammation by altering epithelial cell biology upon binding to its receptor, ICAM-1. ICAM-1 regulates not only viral entry and replication but also signaling pathways that lead to inflammatory mediator production. We recently demonstrated the Syk tyrosine kinase to be an important mediator of HRV-ICAM-1 signaling: Syk regulates replication-independent p38 MAPK activation and IL-8 expression. In leukocytes, Syk regulates receptor-mediated internalization via PI3K. Although PI3K has been shown to regulate HRV-induced IL-8 expression and clathrin-mediated endocytosis of HRV, the role of airway epithelial Syk in this signaling pathway is not known. We postulated that Syk regulates PI3K activation and HRV endocytosis in the airway epithelium. Using confocal microscopy and immunoprecipitation, we demonstrated recruitment of the normally cytosolic Syk to the plasma membrane upon HRV16-ICAM-1 binding, along with Syk-clathrin coassociation. Subsequent incubation at 37 degrees C to permit internalization revealed redistribution of Syk to punctate structures resembling endosomes and colocalization with HRV16. Internalized HRV was not detected in cells overexpressing the kinase inactive Syk(K396R) mutant, indicating that kinase activity was necessary for endocytosis. HRV-induced PI3K activation was dependent on Syk; Syk knockdown by small interfering RNA significantly decreased phosphorylation of the PI3K substrate Akt. Together, these data reveal Syk to be an important mediator of HRV endocytosis and HRV-induced PI3K activation.

Olfactory receptors: transduction, diversity, human psychophysics and genome analysis

The emerging understanding of the molecular basis of olfactory mechanisms allows one to answer some long-standing questions regarding the complex recognition machinery involved. The ability of the olfactory system to detect chemicals at sub-nanomolar concentrations is explained by a plethora of amplification devices, including the coupling of receptors to second messenger generation through GTP-binding proteins. Specificity and selectivity may be understood in terms of a diverse repertoire of olfactory receptors of the seven-transmembrane-domain receptor superfamily, which are probably disposed on olfactory sensory neurons according to a clonal exclusion rule. Signal termination may be related to sets of biotransformation enzymes that process odorant molecules, as well as to receptor desensitization. Many of the underlying molecular components show specific expression in olfactory epithelium, with a well-orchestrated developmental sequence of emergence, possibly related to sensory neuronal function and connectivity requirements. A general model for molecular recognition in biological receptor repertoires allows a prediction of the number of olfactory receptors necessary to achieve efficient detection and sheds light on the analogy between the immune and olfactory systems. The molecular cloning and mapping of a human genomic olfactory receptor cluster on chromosome 17 provides insight into olfactory receptor diversity, polymorphism and evolution. Combined with future genotype-phenotype correlation, with particular reference to specific anosmia, as well as with computer-based molecular modelling, these studies may provide insight into the odorant specificity of olfactory receptors.

Efficacy of a paracetamol-pseudoephedrine combination for treatment of nasal congestion and pain-related symptoms in upper respiratory tract infection

OBJECTIVE

This study compared the efficacy of 1000 mg of paracetamol combined with 60 mg of pseudoephedrine, with that of either paracetamol or pseudoephedrine alone and placebo for the treatment of symptomatic URTI.

RESEARCH DESIGN AND METHODS

A double-blind, parallel group study was performed on 305 patients with URTI (nasal airflow resistance [NAR] of > 0.25 Pa cm3 s and a global pain score of at least moderate intensity). NAR and pain relief/intensity scores were measured over 4 h after initial dose. Patients then dosed up to three times daily for 3 days and recorded nasal congestion and pain intensity scores.

MAIN OUTCOME MEASURES

Nasal airflow conductance (NAC) and pain relief after the initial dose were primary objectives. NAC was calculated from NAR. Pain relief was measured on a 5-point verbal rating scale (VRS) and pain intensity and nasal congestion on a 4-point VRS. Data were analysed using analysis of covariance. Safety was assessed by adverse events.

RESULTS

A single dose of the combination was superior to paracetamol and placebo for NAC (p = 0.0001) and was superior to pseudoephedrine and placebo for pain relief (p < or = 0.048). Multiple doses of the combination were also superior to paracetamol and placebo for decongestion (p < or = 0.021) and were superior to pseudoephedrine and placebo for pain reduction (p < or = 0.0057). All treatments were well tolerated.

CONCLUSIONS

The combination treatment provided a greater decongestant effect than either paracetamol or placebo and better pain relief than either pseudoephedrine or placebo. The additive effect of the combination was apparent for both single and multiple doses.

A comparison of two chlorhexidine gel brushing regimens and a conventional toothpaste brushing regimen for the development of tooth staining over a 6-week period

AIMS

A single-centre, randomized single-blind parallel study was undertaken to compare staining seen with three brushing regimens and to determine subject perception of side effects such as staining and effects on taste.

METHODS

This 6-week parallel study used 157 volunteers who were randomized into one of three treatment groups: (i) brushing in the morning and evening with a normal dose of a 1% chlorhexidine gel, (ii) brushing with a low dose of chlorhexidine gel in the evening and a whitening dentifrice in the morning, and (iii) brushing with a standard fluoride paste in the morning and evening. Following home usage of their allocated products, the study volunteers returned after 3 and 6 weeks to record the amount of stain present. After the 6-week period, subject perception of taste and stain acceptability was determined using a questionnaire.

RESULTS

After 6 weeks of use of the low-dose chlorhexidine gel and whitening dentifrice, significantly more stain was seen compared with the use of a standard dentifrice (P<0.0001). Similarly, significantly more stain was seen with use of the normal-dose chlorhexidine gel compared with the low-dose gel and whitening dentifrice (P=0.0007). Approximately 30% of individuals on the low-dose chlorhexidine gel regimen found the amount of stain unacceptable and 10% noted an effect on their taste perception.

CONCLUSIONS

The use of low dose of chlorhexidine gel at night and a whitening paste in the morning produced a significant amount of stain that 30% of subjects considered unacceptable.

A comparison of enamel erosion by a new sports drink compared to two proprietary products: a controlled, crossover study in situ

OBJECTIVE

The aim of the study was to measure the erosive potential of a prototype sports drink on enamel in a model in situ.

METHODS

The study was a single centre, single blind, randomised crossover design balanced for residual effects involving 18 subjects. The drinks were the prototype formulation containing calcium and maltodextrin (test), two sports drink products containing sugars (drink with calcium and positive control) and water (negative control). During each 15-day study period, subjects wore a palatal removable appliance carrying two flat human enamel specimens. Drinks were imbibed as 250 ml volumes over 10 min 4 times per day. Loss of enamel was measured on days 5, 10 and 15 using a contacting profilometer.

RESULTS

Very little erosion occurred with the test, drink with calcium and negative control drinks and differences between the test and negative control only reached significance at day 15. The positive control produced progressive erosion over time and significantly more than the test or negative control at all time points.

CONCLUSION

The technology of adding calcium with appropriate pH adjustment, which has been applied previously to soft and carbonated drinks to markedly reduce erosive potential, can be applied to sports drinks to the same end. Significant variation in the carbohydrate composition does not influence this outcome.

The 2003 Air Medical Leadership Congress: findings and recommendations

To address important concerns facing the air medical community, 149 air medical transport leaders, providers, consultants, and experts met September 4-6, 2003, in Salt Lake City, Utah, for a 3-day summit-the Air Medical Leadership Congress: Setting the Health Care Agenda for the Air Medical Community. Using data from a Web-based survey, top air medical transport issues were identified in four core areas: safety, medical care, cost/benefit, and regulatory/compliance. This report reviews the findings of previous congresses and summarizes the discussions, findings, recommendations, and proposed industry actions to address these issues as set forth by the 2003 congress participants.

Association between cervical schistosomiasis and cervical cancer. A report of 2 cases

BACKGROUND

HPV is now considered the most important risk factor for the development of cervical intraepithelial neoplasia (CIN) and cancer. Although CIN and cancer have been previously reported in association with cervical schistosomiasis, those reports failed to control for the potential coexistence of high-risk HPV.

CASES

Two women, 1 with high grade CIN and 1 with invasive cervical cancer, were negative for high-risk HPV subtypes. Evidence of cervical and systemic schistosomal infestation was evident in both cases.

CONCLUSION

In support of prior published studies, cervical schistosomiasis seems to be a possible risk factor for the development of CIN and cancer. As populations around the world migrate, North American colposcopists need to become aware of this association.

Analgesic efficacy of sustained release paracetamol in patients with osteoarthritis of the knee

AIMS

Paracetamol is widely recommended as the initial treatment for pain associated with osteoarthritis (OA). A sustained release (SR) paracetamol formulation (Panadol Extend) was compared with standard immediate release (IR) paracetamol (Panadol) in patients with knee pain secondary to OA. The primary parameter for assessment of efficacy was patient-assessed global pain relief as determined on day 8 of the treatment period.

METHODS

A double-blind, double-dummy, randomized study was conducted. Patients (n=403) were treated for 7 days with paracetamol 4 g day(-1) (SR paracetamol, two 665 mg tablets taken three times daily; IR paracetamol, two 500 mg tablets taken four times daily). Patients completed daily pain measurements and assessed global pain relief at the end of the study. Therapeutic noninferiority was defined on the basis of achieving statistical noninferiority for global pain relief.

RESULTS

Analysis of the primary parameter for the intention to treat population showed that the difference in proportion of patients (SR-IR paracetamol) achieving a successful response on day 8 was -0.7%; 90% CI (-8.82%, 7.45%), P=0.890. For the per protocol population the difference in proportion was -3.0%; 90% CI (-11.61%, 5.66%), P=0.571. As the lower bound of the 90% CI for the treatment difference in each case was greater than the prespecified value (-15%), SR paracetamol was considered to be statistically noninferior to IR paracetamol in terms of pain relief. The treatments were not significantly different for any of the secondary parameters in either populations.

CONCLUSIONS

SR paracetamol taken three times daily was statistically and therapeutically noninferior to IR paracetamol taken four times daily in patients with knee pain due to OA. SR paracetamol may be more convenient for patients with chronic pain and has the potential to enhance compliance and therefore pain relief.

Direct measurement of ferrous ion transport across membranes using a sensitive fluorometric assay

The fluorophore, Phen Green SK (PGSK), was assessed for its suitability to be used in an assay for ferrous ion transport into membrane vesicles. The long wavelengths of excitation and emission (506 and 520 nm, respectively) enable PGSK fluorescence to be detected in membranes, such as the chloroplast inner envelope, that contain high levels of carotenoids which absorb light at lower wavelengths. At low concentrations of Fe2+, less than 3 microM, the interaction between PGSK and Fe2+ appears to result in both static and dynamic quenching of the PGSK fluorescence. The characteristics of this quenching were used to develop a calibration curve to determine the concentration of free Fe2+ at these low concentrations. Pronounced quenching of PGSK fluorescence entrapped within chloroplast inner envelope membrane vesicles was observed when Fe2+ was added. The extent of quenching of PGSK fluorescence trapped inside asolectin vesicles on Fe2+ addition was much less. The kinetics of the quenching of PGSK fluorescence by Fe2+ in vesicles was quite different from that for PGSK and Fe2+ in solution. Using the calibration curve developed for interaction of PGSK and low Fe2+ concentrations the initial rates of iron transport could be determined for the chloroplast inner envelope membranes.

A genome-wide scan suggests a locus on chromosome 1q21-q23 contributes to normal variation in plasma cholesterol concentration

To identify genes that influence plasma cholesterol, triglyceride, and high-density and low-density lipoproteins concentrations we conducted a genome-wide scan using 354 polymorphic markers spaced at 10-cM intervals in 75 obese but otherwise normal human families. The results of the genome scan using sibling pair analysis of quantitative phenotypes suggested that 1q21-q23 contains a locus that influences plasma cholesterol concentration. Chromosome 12 gave evidence of linkage to plasma triglyceride concentration (D12SPAH) and chromosomes 3, 6, 7, 10, 11, 17, and 20 yielded additional evidence of linkage for lipid phenotypes at lower levels of statistical significance. Allele sharing for markers near prominent candidate genes was either very weakly related or unrelated to sibling similarity for lipid concentrations. Together these results suggest that genes with important roles in regulating normal cholesterol and triglyceride concentrations do not coincide with the location of previously known candidate genes.

Incorporation of conformationally constrained beta-amino acids into peptides

The use of norbornene units to induce the formation of beta-sheet and beta-turn type structures in peptides is discussed. The norbornene unit is readily prepared by a desymmetrization reaction and is easily incorporated into a peptide chain. Depending upon the exact nature of the norbornene unit, it is possible to form structures which resemble parallel beta-sheets, antiparallel beta-sheets or beta-turns. Similar peptide analogues incorporating a cis-2-amino-cyclopropane carboxylic acid unit can also be prepared. As an illustration of the application of this chemistry, a short, asymmetric synthesis of conformationally constrained metalloprotease inhibitors is presented.

An assistive device for the treatment of positional plagiocephaly

An assistive device (AD) was used to treat 122 infants with moderate-to-severe positional plagiocephaly. Clinical evaluations indicate that the AD provided the most benefit when applied to 2- to 8-month-old children. Our results suggest that the AD may join molding helmets and physical therapy as a treatment for moderate-to-severe positional plagiocephaly in infants under the age of 1 year.

Cytokine and cytokine receptor concentrations in bone marrow supernatant from patients with HIV: correlation with hematologic parameters

BACKGROUND

To determine the concentrations of tumor necrosis factor (TNF) alpha, soluble TNF receptors (sTNFR), interleukin (IL)-1 beta, gamma-interferon (IFN), macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, and RANTES to which hematopoietic progenitors are exposed in vivo in HIV patients and the correlation of these concentrations with hematologic parameters, cytokine and cytokine receptor concentrations were measured by ELISA in bone marrow aspirate supernatants from 19 HIV patients undergoing diagnostic evaluation and 14 healthy paid volunteer controls. IL-1 beta and gamma-IFN were rarely detectable. All cytokines/receptors detectable in marrow supernatant, except RANTES, showed mean concentrations 1.6- to 6.2-fold higher in patients with HIV compared to healthy controls.

METHODS

Elevated TNF-alpha and MIP-1 beta were associated with marrow involvement by lymphoma, Hodgkin disease, or mycobacterial infection. Concentrations of all cytokines/receptors measured correlated with the severity of anemia. CD8+ lymphocytes were inversely correlated with concentrations of all cytokines measured other than MIP-1 alpha. To identify differences specific to HIV infection, marrow supernatant cytokine concentrations were also evaluated in 9 non-HIV patients undergoing diagnostic marrow examination. Significant differences were observed in TNF alpha, MIP-1 alpha, and IL-1 beta concentrations.

RESULTS

These studies demonstrate that concentrations of these cytokines and receptors are elevated in bone marrow supernatant of HIV-infected patients with hematologic abnormalities, and that these concentrations correlate with clinical parameters in these patients.

CONCLUSIONS

Evaluation of local concentrations of cytokines may be relevant to understanding tissue-specific pathology in HIV-infected individuals.

Inhibition of human erythroid colony formation by ceramide

In previous studies, we have demonstrated that the inhibitory effects of tumor necrosis factor (TNF) and interleukin (IL)-1 on human erythroid colony formation are indirect and mediated by beta and gamma interferon (IFN), respectively, which act directly upon erythroid colony forming units (CFU-E). The in vitro inhibitory effect of gammaIFN but not betaIFN is reversed by exposure to high concentrations of recombinant human (rh) erythropoietin (EPO). Ceramide, a product of sphingomyelin hydrolysis, is a known mediator of apoptotic effects of TNF, IL-1, and gammaIFN. In this report, the effects of ceramide on CFU-E colony formation and its implication in the model described above are evaluated. Endogenous ceramide produced by exposure to bacterial sphingomyelinase (0.2-2.0 U/mL) and exogenous cell-permeable ceramide (C2-ceramide; 5 and 10 mM) significantly inhibited bone marrow CFU-E colony formation. This effect was reversed by the ceramide antagonist sphingosine-1-phosphate (S-1-P). Inhibition of CFU-E by rhgammaIFN, but not rhbetaIFN, was significantly reversed by S-1-P. rhEPO 10 U/mL reversed CFU-E inhibition by C2-ceramide 10 mM. Exposure of marrow cells to rhgammaIFN led to a 57% increase in ceramide content. The present study demonstrates that colony formation by human CFU-E is inhibited by endogenous and exogenous ceramide, and that inhibition by rhgammaIFN can be reversed by the ceramide antagonist S-1-P. Inhibition of CFU-E colony formation by ceramide and by are both reversed by high concentrations of rhEPO. These findings strongly suggest that ceramide mediates inhibition of human CFU-E colony formation by gammaIFN.

Genome scan for human obesity and linkage to markers in 20q13

Obesity is a highly prevalent, multigenic trait that predicts increased morbidity and mortality. Here we report results from a genome scan based on 354 markers in 513 members of 92 nuclear families ascertained through extreme obesity and normal body weight. The average marker interval was approximately 10 cM. We examined four correlated obesity phenotypes, including the body-mass index (BMI) (both as a quantitative trait and as a discrete trait with a threshold of BMI > or /=30 kg/m2) and percentage of fat (both as a quantitative trait and as a discrete trait with a threshold of 40%) as assessed by bioelectrical impedance. In the initial stage of the genome scan, four markers in 20q gave positive evidence for linkage, which was consistent across most obesity phenotypes and analytic methods. After saturating 20q with additional markers (25 markers total) in an augmented sample of 713 members from 124 families, we found linkage to several markers in a region, 20q13, previously implicated in both human and animal studies. Three markers (D20S107, D20S211, and D20S149) in 20q13 had empirical P values (based on Monte Carlo simulations, which controlled for multiple testing) < or /=. 01 for single-point analysis. In addition, the parametric, affecteds-only analysis for D20S476 yielded a LOD score of 3.06 (P=. 00009), and the affected-sib-pair test yielded a LOD score of 3.17 (P=.000067). Multipoint analyses further strengthened and localized these findings. This region includes several plausible candidate genes for obesity. Our results suggest that one or more genes affecting obesity are located in 20q13.

A polymorphism in the 5' untranslated region of the human ob gene is associated with low leptin levels

OBJECTIVE

To search the human ob gene for mutations and evaluate their role in massive obesity.

DESIGN

Direct mutation screening of the gene and case-control association study. Multivariate analyses for evaluation of differences in clinical parameters.

SUBJECTS

Primary mutation screening: 24 morbidly obese subjects (body mass index (BMI) > 40 kg/m2). Association study: 395 unrelated morbidly obese subjects (BMI > 40 kg/m2), 121 lean, non-diabetic control individuals, 72 women of a random sample with an average BMI 32.5 kg/m2.

RESULTS

We report the finding of a DNA variant in exon 1 of the human ob gene (A --> G substitution, base + 19). This variant showed a prevalence of 62% in our study population. Association analyses under different genetic models (dominant, co-dominant, recessive) showed no significant evidence for an association of this variant with BMI. However, obese individuals homozygous for the G-allele showed significantly lower leptin concentrations compared to obese patients either heterozygous or homozygous for the A-allele after correction for BMI.

CONCLUSION

Recent linkage studies have shown evidence for linkage of the hsob locus with obesity. Our study provides further evidence that a defect in the ob gene in linkage disequilibrium with the G-allele of exon 1 might be involved in obesity by affecting leptin concentrations.

The genetics of obesity

Despite the influence of obesity in predisposing to many diseases, and evidence for high heritability, efforts to identify human genes with major effects on bodyweight have not yet been successful. In contrast, remarkable progress has been made in the identification and characterization of the genes mutated in five monogenic mouse models of obesity. These genes have led to new insights into the etiology of obesity and provide promising targets for therapeutic intervention.

Serum transferrin receptor levels in patients undergoing evaluation of iron stores: correlation with other parameters and observed versus predicted results

Serum transferrin receptor (sTfR) concentrations were measured in specimens from 77 patients undergoing serum ferritin determination, and the results correlated with serum ferritin, serum iron, serum total iron-binding capacity (TIBC) saturation, erythrocyte mean corpuscular volume (MCV), and mean corpuscular haemoglobin (MCH). All parameters exhibited the expected inverse correlation with sTfR; this correlation was statistically significant for all parameters except serum iron concentration. The frequency with which iron deficiency (defined as absence of stainable marrow iron) is observed in patients with particular ferritin values in this centre was determined and used to estimate the expected number of iron deficient patients in the present study. In no setting were significantly fewer sTfR levels > 3.05 micrograms/ml observed than expected. However, significantly greater than expected numbers of elevated sTfR values were observed in patients with serum ferritin > 220 micrograms/l (P = 0.002). The results suggest that the sTfR level is probably not useful as a single test for identification of iron deficiency in unselected patients.

Genetic studies of the sulfonylurea receptor gene locus in NIDDM and in morbid obesity among French Caucasians

The sulfonylurea receptor (SUR) is a key component in glucose-stimulated insulin secretion. Obesity and NIDDM are frequently associated and share some metabolic abnormalities, suggesting that they might also share some susceptibility genes. Thus, the SUR encoding gene is a plausible candidate for a primary pancreatic beta-cell defect and thus for hyperglycemia and weight gain. Through association and linkage studies, we have investigated the potential role of the SUR gene in families with NIDDM and in two independent sets of morbidly obese families. The exon 22 T-allele at codon 761 was more common in patients with NIDDM (7.7%) and morbid obesity (7.8%) than in control subjects (1.8%, P = 0.030 and P = 0.023, respectively). This variant was associated with morbid obesity (odds ratio 3.71, P = 0.017) and NIDDM (odds ratio 2.20, P = 0.04; association dependent on BMI). Although the frequencies for intron 24 variant were similar in all groups, morbidly obese patients homozygous for the c-allele had a more deleterious form of obesity. Sib-pair linkage studies with NIDDM in French Caucasian families gave no evidence for linkage to the SUR locus. However, in one set of the obese families, we found an indication for linkage with a SUR-linked microsatellite marker (D11S419, P = 0.0032). We conclude that in Caucasians, the SUR locus may contribute to the genetic susceptibility to NIDDM and obesity.

Inhibition of marrow CFU-E colony formation from human immunodeficiency virus-infected patients by beta- and gamma-interferon

Increased production of cytokines such as beta-interferon (IFN) and gamma-IFN may contribute to the anemia frequently observed in patients with human immunodeficiency virus (HIV) infection. The hypothesis that HIV infection might enhance the susceptibility of erythroid progenitors to cytokine-mediated inhibition was evaluated by comparing the effects of beta- and gamma-IFN on in vitro colony formation by marrow erythroid colony-forming units (CFU-E) from HIV patients, normal volunteers, and anemic non-HIV-infected individuals. CFU-E colony formation from HIV patients was not significantly different from controls, and the degree of inhibition by IFN did not differ among patient subsets. HIV infection does not appear to impair baseline CFU-E colony formation, nor does it appear to enhance the susceptibility of CFU-E to suppression by cytokines.

Serum chemokine levels in patients with non-progressing HIV infection

OBJECTIVE

To evaluate serum chemokines, macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta and RANTES, concentrations in non-progressing HIV-infected patients and AIDS patients.

SETTING

University Hospital-based AIDS Clinical Trials Unit.

DESIGN/METHODS

Serum MIP-1 alpha, MIP-1 beta and RANTES levels were determined by enzyme-linked immunosorbent assay using archived serum specimens obtained on two occasions at least 1.8 years apart.

PATIENT SELECTION

Long-term non-progressing HIV-infected adult patients were identified from clinic records. For each non-progressing patient two adult AIDS patients with initial documentation of seropositivity the same year and the same length of follow-up were selected.

RESULTS

Four long-term non-progressing patients and eight AIDS patients were studied. Neither the duration of known HIV positivity at the time of specimen collection nor the length of time between specimen collections differed significantly between non-progressing patients and AIDS patients. Serum levels of MIP-1 alpha, MIP-1 beta and RANTES in specimens obtained either early or later in the course of HIV infection did not differ significantly between non-progressing patients and AIDS patients. In the two patient subsets, significant differences in serum chemokine levels over time were not observed. The rate of change of serum chemokine concentration over time also did not differ between non-progressing patients and AIDS patients. Serum MIP-1 alpha and MIP-1 beta levels did not reach levels reported to suppress HIV proliferation in vitro. When expressed as a quantity per peripheral blood CD8+ lymphocyte, AIDS patients exhibited significantly greater levels of MIP-1 alpha, MIP-1 beta and RANTES than non-progressing HIV patients (P < 0.05). These values did not exhibit a significant variation over time.

CONCLUSIONS

Serum MIP-1 alpha, MIP-1 beta and RANTES levels do not distinguish patients with AIDS from patients with non-progressing HIV infection. Variations in levels of these chemokines do not explain individual variation in the natural history of HIV infection.

Indication for linkage of the human OB gene region with extreme obesity

Obesity is one of the most significant risk factors for hypertension, coronary heart disease, and NIDDM (Frayn KN, Coppack SW: Insulin resistance, adipose tissue and coronary heart disease. Clin Sci 82:1-8, 1992; Kaplan NM: The deadly quartet: upper-body obesity, glucose intolerance, hypertriglyceridemia, and hypertension. Arch Intern Med 149:1514-1520, 1989). While family segregation, adoption, and twin studies have indicated that degree of adiposity has a significant genetic component (Stunkard AJ, Harris JR, Pedersen NL, McClearn GE: The body-mass index of twins who have been reared apart. N Engl J Med 322:1483-1487, 1990; Bouchard C, Despres J-P, Mauriege P: Genetic and nongenetic determinants of regional fat distribution. Endocr Rev 14:72-93, 1993), the genes and predisposing mutations remain poorly understood. This is in contrast to several well-defined genetic models for obesity in rodents, particularly the mouse obese (ob) gene, in which loss-of-function mutations cause severe obesity. Recent studies have demonstrated a substantial reduction in body fat when recombinant ob protein (leptin) is administered to mice. To test the relevance of these observations to human obesity, the location of the human homologue (OB) was established by radiation hybrid mapping and eight microsatellite markers spanning the OB gene region (7q3l.3) were genotyped in 101 obese French families. Affected-sib-pair analyses for extreme obesity, defined by BMI >35 kg/m2, revealed suggestive evidence for linkage to three markers located within 2 cM of the OB gene (D7S514, D7S680, and D7S530). The OB gene is therefore a candidate for genetic predisposition to extreme obesity in a subset of these families.

Identification of Genes Predisposing to Clinically Severe Obesity: An Approach

BACKGROUND: Familial correlations, twin studies and adoption studies have all indicated that human obesity has a substantial genetic component. To date, obesity genes have only been identified using mouse models. METHODS: In an attempt to identify human obesity genes large numbers of multigenerational families, in whom extreme obesity segregates, are currently being collected. RESULTS AND CONCLUSIONS: Relative risk estimates and models of genetic heterogeneity indicate that at least 500 affected sibling pairs will need to be collected to identify major genes.

Effectiveness of computer-generated (virtual reality) graded exposure in the treatment of acrophobia

OBJECTIVE

The authors' goal was to examine the efficacy of computer-generated (virtual reality) graded exposure in the treatment of acrophobia (fear of heights).

METHOD

Twenty college students with acrophobia were randomly assigned to virtual reality graded exposure treatment (N = 12) or to a waiting-list comparison group (N = 8). Seventeen students completed the study. Sessions were conducted individually over 8 weeks. Outcome was assessed by using measures of anxiety, avoidance, attitudes, and distress associated with exposure to heights before and after treatment.

RESULTS

Significant differences between the students who completed the virtual reality treatment (N = 10) and those on the waiting list (N = 7) were found on all measures. The treatment group was significantly improved after 8 weeks, but the comparison group was unchanged.

CONCLUSIONS

The authors conclude that treatment with virtual reality graded exposure was successful in reducing fear of heights.

Delayed Postoperative Nonembolic Neurologic Deficit After Left Internal Carotid Endarterectomy in Presence of Known Contralateral Carotid Artery Occlusion

Neurologic sequelae are known complications of carotid endarterectomy. The current overall perioperative stroke rate is 2-5% (1,2). The incidence of perioperative morbidity and mortality is increased in certain patient subgroups, including neurologically unstable patients and patients who have known contralateral common or internal carotid artery occlusion (3-9). We present the case of a patient who had known total right carotid artery occlusion and a known previous right cerebrovascular accident who sustained a contralateral deficit after a left internal carotid thromboendarterectomy with vein patch angioplasty.