Models of the pulsatile hydrodynamics of cerebrospinal fluid flow in the normal and abnormal intracranial system

Images obtained from magnetic resonance imaging have helped to ascertain that both the cerebrospinal fluid (CSF) and brain move in a pulsatile manner within the cranium. However, these images are not able to reveal any quantitative information on the physiological forces that are associated with pulsatile motion. Understanding both the pressure and velocity flow field of CSF in the ventricles is important to help understand the mechanics of hydrocephalus. Four separate fluid structure interaction models of the ventricular system in the sagittal plane were created for this purpose. The first model was of a normal brain. The second and third models were pathological brain models with aqueductal stenosis at various locations along the fluid pathway. The fourth model was of a hydrocephalic brain. Results revealed the hydrodynamics of CSF pulsatile flow in the ventricles of these models. Most importantly, it has also revealed the different changes in CSF pulsatile hydrodynamics caused by the various locations of fluid flow obstructions.

Movement of the tongue during normal breathing in awake healthy humans

Electromyographic (EMG) activity of the airway muscles suggest that genioglossus is the primary upper airway dilator muscle. However, EMG data do not necessarily translate into tissue motion and most imaging modalities are limited to assessment of the surfaces of the upper airway. In this study, we hypothesized that genioglossus moves rhythmically during the respiratory cycle and that the motion within is inhomogeneous. A 'tagged' magnetic resonance imaging technique was used to characterize respiratory-related tissue motions around the human upper airway in quiet breathing. Motion of airway tissues at different segments of the eupnoeic respiratory cycle was imaged in six adult subjects by triggering the scanner at the end of inspiration. Displacements of the 'tags' were analysed using the harmonic phase method (HARP). Respiratory timing was monitored by a band around the upper abdomen. The genioglossus moved during the respiratory cycle. During expiration, the genioglossus moved posteriorly and during inspiration, it moved anteriorly. The degree of motion varied between subjects. The maximal anteroposterior movement of a point tracked on the genioglossus was 1.02 +/- 0.54 mm (mean +/- s.d.). The genioglossus moved over the geniohyoid muscle, with minimal movement in other muscles surrounding the airway at the level of the soft palate. Local deformation of the tongue was analysed using two-dimensional strain maps. Across the respiratory cycle, positive strains within genioglossus reached peaks of 17.5 +/- 9.3% and negative strains reached peaks of -16.3 +/- 9.3% relative to end inspiration. The patterns of strains were consistent with elongation and compression within a constant volume structure. Hence, these data suggest that even during respiration, the tongue behaves as a muscular hydrostat.

Risk factors for symptoms of childhood asthma, allergic rhinoconjunctivitis and eczema in the Pacific: an ISAAC Phase III study

BACKGROUND AND METHODS

Phase III of the International Study of Asthma and Allergies in Childhood (ISAAC) was conducted in eight Pacific countries, five of which (Samoa, Fiji, Tokelau, French Polynesia and New Caledonia) collected environmental questionnaire (EQ) data. We report the findings of the EQ analyses below.

RESULTS

The major factors associated with current wheeze were regular margarine consumption (prevalence odds ratio [POR] 1.19, 95%CI 1.01-1.40), paracetamol use (POR 1.35, 95%CI 1.11-1.64), electric cooking (POR 1.42, 95%CI 1.11-1.80), regular exercise (POR 1.44, 95%CI 1.18-1.75) and maternal smoking (POR 1.16, 95%CI 1.01-1.33). Protective factors included having older siblings (two or more POR 0.69, 95%CI 0.58-0.82; one POR 0.86, 95%CI 0.71-1.05), and being born in the country of the survey (POR 0.74, 95%CI 0.63-0.87). Risk factors for rhinoconjunctivitis included regular consumption of meat, butter, margarine and nuts, regular exercise, regular television viewing, paracetamol use and passive smoking. Eczema was associated with regular meat, pasta and butter consumption, regular television viewing, paracetamol use and passive smoking.

CONCLUSIONS

Regular meat and margarine consumption, paracetamol use, electric cooking and passive smoking are risk factors for symptoms of asthma, rhinoconjunctivitis and eczema in the Pacific. However, most of these associations were weak, and account for only a small proportion of cases.

Farm exposure in utero may protect against asthma, hay fever and eczema

The aim of the present study was to assess which factors contribute to the lower prevalence of allergic diseases in farmers' children, and the importance of timing of exposure. In a cross-sectional questionnaire survey, asthma symptoms, hay fever and eczema were assessed, as well as current, early and prenatal farm-related exposures in 1,333 farmers' children and 566 reference children aged 5-17 yrs. Farmers' children had a lower incidence of asthma symptoms and eczema. Current and maternal exposure during pregnancy to animals and/or grain and hay reduced the risk of asthma symptoms, hay fever and eczema. The exposure-response association for maternal exposure was nonlinear for most outcomes. After mutual adjustment, the effects of prenatal exposure remained unchanged whereas current exposure remained protective only for asthma medication, asthma ever and hay fever. Exposure during the first 2 yrs was not associated with symptoms, after controlling for prenatal exposure. A combination of prenatal and current exposure was most strongly associated with wheeze (odds ratio (OR) 0.48, 95% confidence interval (CI) 0.28-0.80), asthma medication (OR 0.50, 95% CI 0.30-0.82), asthma ever (OR 0.50, 95% CI 0.33-0.76), hay fever (OR 0.47, 95% CI 0.30-0.73) and eczema (OR 0.46, 95% CI 0.30-0.70). Prenatal exposure may contribute to the low prevalence of asthma, hay fever and eczema in farmers' children, but continued exposure may be required to maintain optimal protection.

Diurnal Variation in Maximal and Submaximal Strength, Power and Neural Activation of Leg Extensors in Men: Multiple Sampling Across Two Consecutive Days

This study aimed to compare day-to-day repeatability of diurnal variation in strength and power. Thirty-two men were measured at four time points (07 : 00 - 08 : 00, 12 : 00 - 13 : 00, 17 : 00 - 18 : 00, and 20 : 30 - 21 : 30 h) throughout two consecutive days (day 1 and day 2). Power during loaded squat jumps, torque and EMG during maximal (MVC) and submaximal (MVC40) voluntary isometric knee extension contractions were measured. The EMG/torque ratio during MVC and MVC40 was calculated to evaluate neuromuscular efficiency. A significant time-of-day effect with repeatable diurnal patterns was found in power. In MVC, a significant time-of-day effect was present on day 2, whereas day 1 showed a typical but nonsignificant diurnal pattern. EMG and antagonist co-activation during MVC remained statistically unaltered, whereas neuromuscular efficiency improved from day 1 to day 2. A similar trend was observed in MVC40 neuromuscular efficiency with significant time-of-day and day-to-day effects. Unaltered agonist and antagonist activity during MVC suggests that modification at the muscular level was the primary source for the diurnal variation in peak torque. A learning effect seemed to affect data in MVC40. In conclusion, the second consecutive test day showed typical diurnal variation in both maximum strength and power with no day-to-day effect of cumulative fatigue.

Molecular epidemiology of avian leukosis virus subgroup J and evolutionary history of its 3' untranslated region

Avian leukosis subgroup J (ALV-J) causes a variety of tumors and mortality in meat-type chickens. Since its discovery in the late 1980s, ALV-J has spread to breeding stock produced by most primary breeding companies of North America, the European Union, and Asia. ALV-J seems to have been eradicated from elite breeding stock produced by most primary breeders, albeit ALV-J still circulates in some commercial poultry. This study was undertaken to examine the molecular epidemiology and evolution of ALV-J detected in breeding stock and broiler chickens representing eight primary breeding companies over a period of approximately 20 yr (1988-2007). The redundant transmembrane region of the envelope gene has been deleted in some isolates, suggesting that this region is dispensable for viral fitness. Within the 3' untranslated region (3' UTR), the direct repeat 1 was present in 100% of the ALV-J isolates studied. In contrast, the E element has undergone substantial deletions in >50% of the ALV-J proviruses studied. Overall, the unique region 3 was the least conserved within the 3' long terminal repeat (LTR), albeit the transcriptional regulatory elements typical of avian retroviruses (CAAT, CArG, PRE, TATA, and Y boxes) were highly conserved. The direct repeat region of the LTR was identical in all of the proviruses, and the 3' unique region 5 was relatively well conserved. Thus, the 3' UTR of ALV-J has evolved rapidly, reflecting significant instability of this region. Some of the mutations in the 3' UTR have resulted in the emergence of moderately distinct genetic lineages representing each primary breeding company from which ALV-J was isolated.

Differential effects of melatonin on hippocampal neurodegeneration in different aged accelerated senescence prone mouse-8

OBJECTIVES

A purpose of this study is to compare the differential effects of melatonin on hippocampal neurodegeneration in accelerated senescence prone mouse-8 (SAMP8) which is initiated treatment at different age.

METHODS

The 4-months old SAMP8 mice were injected subcutaneously with melatonin (1 mg/kg/day) for 4 months. Similar treatments were performed in the 7-months old mice. When the animals were complete 11-months old, a series of tests were performed. Y maze test and Eight-arm radial maze task were used to assess cognitive performance. Hippocampal pyramidal cells were estimated by Nissl's staining. By using Gomori's methenamine silver methods, the methenamine silver staining granules (MSSG) were observed in area CA1 of hippocampus. A computer-assisted morphometric study was carried out on the ultrastructure of perikaryal CA1 pyramidal cell mitochondria. The volume density (Vv), surface density (Sv), numerical density (Nv) and mean volume (V) of the mitochondria were calculated.

RESULTS

Melatonin treatment obviously reduced the deposition of MSSG and elevated hippocampal pyramidal cell number while improving the learning and memory deficits of SAMP8. The mice initiated treatment from 4-months old exhibited a greater response to melatonin supplementation than 7-months old mice. It also decreased mean volume (V) and significantly elevated the Sv and Nv of the mitochondria in hippocampal CA1 region. However, 7-months old mice showed little effects on it.

CONCLUSIONS

Our results indicate that the protective effects of melatonin on hippocampal neurodegeneration of SAMP8 are age dependent.

Robust combination of multiple diagnostic tests for classifying censored event times

Recent advancement in technology promises to yield a multitude of tests for disease diagnosis and prognosis. When there are multiple sources of information available, it is often of interest to construct a composite score that can provide better classification accuracy than any individual measurement. In this paper, we consider robust procedures for optimally combining tests when test results are measured prior to disease onset and disease status evolves over time. To account for censoring of disease onset time, the most commonly used approach to combining tests to detect subsequent disease status is to fit a proportional hazards model (Cox, 1972) and use the estimated risk score. However, simulation studies suggested that such a risk score may have poor accuracy when the proportional hazards assumption fails. We propose the use of a nonparametric transformation model (Han, 1987) as a working model to derive an optimal composite score with theoretical justification. We demonstrate that the proposed score is the optimal score when the model holds and is optimal "on average" among linear scores even if the model fails. Time-dependent sensitivity, specificity, and receiver operating characteristic curve functions are used to quantify the accuracy of the resulting composite score. We provide consistent and asymptotically Gaussian estimators of these accuracy measures. A simple model-free resampling procedure is proposed to obtain all consistent variance estimators. We illustrate the new proposals with simulation studies and an analysis of a breast cancer gene expression data set.

Seasonal variation of red blood cell variables in physically inactive men: effects of strength training

The purpose of this study was to investigate if strength training affects red blood cell variables in physically inactive men when taking into account seasonal variations. Seventy-four men aged 20-45 were randomly assigned to training (n = 52) and control (n = 22) groups. Training group underwent 20-week progressive strength training. Body composition and maximal voluntary contraction (MVC) during knee extension were measured before and after intervention. Fasting blood samples were analysed for haematocrit (Hct), count of red blood cells (RBC), haemoglobin (Hb), mean cell haemoglobin concentration (MCHC), and mean cell volume (MCV) at baseline, 10-week and 20-week follow-up. MVC and lean body mass increased in the training group. Hct, Hb and MCHC showed seasonal variation in the control group. The training group increased their Hct from 44.7 +/- 2.6 % to 45.4 +/- 2.5 % (p = 0.026) while the control group decreased their Hct from 44.3 +/- 2.2 % to 43.1 +/- 2.6 % (p = 0.037) after 20-week intervention. By contrast to the control group, the training group increased their Hct (p = 0.001), RBC (p = 0.005) and decreased their MCHC (p < 0.001) from 10-week to 20-week follow-up. We concluded that strength training could affect seasonal variation patterns of red cell variables. Unlike "sport anaemia" induced by endurance training, 20-week strength training elevated Hct.

Characterization of seven new HLA alleles from the Henan and Gansu Provinces of China

Four new class I and three class II alleles have been found in Chinese individuals.

Measurement of EMG activity with textile electrodes embedded into clothing

Novel textile electrodes that can be embedded into sports clothing to measure averaged rectified electromyography (EMG) have been developed for easy use in field tests and in clinical settings. The purpose of this study was to evaluate the validity, reliability and feasibility of this new product to measure averaged rectified EMG. The validity was tested by comparing the signals from bipolar textile electrodes (42 cm(2)) and traditional bipolar surface electrodes (1.32 cm(2)) during bilateral isometric knee extension exercise with two electrode locations (A: both electrodes located in the same place, B: traditional electrodes placed on the individual muscles according to SENIAM, n=10 persons for each). Within-session repeatability (the coefficient of variation CV%, n=10) was calculated from five repetitions of 60% maximum voluntary contraction (MVC). The day-to-day repeatability (n=8) was assessed by measuring three different isometric force levels on five consecutive days. The feasibility of the textile electrodes in field conditions was assessed during a maximal treadmill test (n=28). Bland-Altman plots showed a good agreement within 2SD between the textile and traditional electrodes, demonstrating that the textile electrodes provide similar information on the EMG signal amplitude to the traditional electrodes. The within-session CV ranged from 13% to 21% in both the textile and traditional electrodes. The day-to-day CV was smaller, ranging from 4% to 11% for the textile electrodes. A similar relationship (r(2)=0.5) was found between muscle strength and the EMG of traditional and textile electrodes. The feasibility study showed that the textile electrode technique can potentially make EMG measurements very easy in field conditions. This study indicates that textile electrodes embedded into shorts is a valid and feasible method for assessing the average rectified value of EMG.

Lifelong farm exposure may strongly reduce the risk of asthma in adults

BACKGROUND

Farm exposures may protect against childhood asthma, hay fever and eczema. Whether farm exposures also confer protection in adult farmers remains unclear. Moreover, little is known about the role of timing of exposure. We assessed the effects of current and childhood farm exposures on asthma, hay fever and eczema in farmers and a rural nonfarming control population.

METHODS

We conducted a cross-sectional questionnaire survey in 2509 farming families (response rate 78%) and 1001 nonfarming families (response rate 67%), which included 4288 farmers and 1328 nonfarmers.

RESULTS

Farmers were less likely to have asthma symptoms, hay fever and eczema; no significant differences were observed among dairy, sheep and beef, and horticulture farmers. A combination of current and childhood exposure was more strongly associated with shortness of breath (OR 0.50, CL 0.39-0.66), wheeze (OR 0.60, CL 0.49-0.73), asthma medication (OR 0.48, CL 0.37-0.63); and asthma ever (OR 0.56, CL 0.46-0.68) than current exposure alone (OR 0.63, CL 0.47-0.84; OR 0.80, CL 0.65-0.99; OR 0.68, CL 0.51-0.9; OR 0.69, CL 0.56-0.85 respectively) or childhood exposure alone (OR 0.97, CL0.65-1.44; OR 1.01, CL 0.75-1.34; OR 0.78, CL 0.51-1.19; OR 0.87, CL 0.63-1.19 respectively). Moreover, the combined number of years of farm exposure in childhood and adulthood showed a dose-dependent inverse association with symptom prevalence.

CONCLUSIONS

Although both current and childhood farm exposures may play a role in the observed low prevalence of asthma symptoms in adult farmers, continued long-term exposure may be required to maintain optimal protection.

Asthma control in a random sample of New Zealand adolescent asthmatics

Asthma control, defined by asthma symptoms and lung function, and asthma medication use, was assessed in 123 adolescent asthmatics. Sputum eosinophilia (>or= 2.5% eosinophils) and bronchial hyperresponsiveness (BHR) to hypertonic saline were also measured to assess whether these additional objective parameters might aid in determining asthma control; 54.5% of subjects had adequately controlled asthma; 50.4% of all subjects reported inhaled corticosteroid use in the preceding 12 months; however, only 22.3% reported regular use. Although BHR and median eosinophil numbers were significantly higher in the inadequately controlled asthmatics, BHR and sputum eosinophilia had poor sensitivity for detecting inadequate asthma control.

A phase I/II study of OGX-011 and a gemcitabine (GEM)/platinum regimen as first-line therapy in 85 patients with advanced non-small cell lung cancer

7596

Background: OGX-011 is a second-generation antisense oligonucleotide designed to knockdown expression of the cytoprotective chaperone, clusterin, thereby facilitating apoptosis and sensitization of many human cancer cell-lines to chemotherapy. Methods: Eligibility criteria: stage IIIB/IV NSCLC; no prior chemotherapy; =1 measurable lesion; ECOG =1; adequate organ function; no active CNS metastasis. Treatment: infusion of OGX-011 initial loading doses (3 in 1 week), followed by weekly OGX-011 with standard chemotherapy: GEM (1,250 mg/m2) Days 1+8 and either cisplatin (75 mg/m2) or carboplatin (AUC=5) Day 1 q21 days, (maximum 6 cycles). Results: 85 pts (phase I=10 and phase II=75) enrolled between Dec 04 and Nov 06. Based on phase I results, dose of OGX-011 was 640 mg. Data is available on the first 53 pts; all received =1 dose of OGX-011 and were considered evaluable for safety and efficacy. Demographics: female (47%); stage IV (87%); median age 61 (45–79) yrs; ECOG PS =1 (62%); median no. of cycles delivered was 4. Principal grade 3/4 toxicities were hematologic: neutropenia (32%) + thrombocytopenia (17%). Other common toxicities included fatigue, nausea, vomiting, fever, chills, constipation, + anorexia. Two serious adverse events previously reported as associated with GEM/platinum therapy were documented: acute cortical blindness with stroke + thrombotic thrombocytopenic purpura. Responses: 12 confirmed PR (ORR = 23%). Median PFS is 101 days (53–260+). Of the first 24 patients who have all been followed for =1 yr, median survival is 383 days (19–751+); 14/24 (58%) survived >1 yr; 10/14 remain alive as of 12/13/06. Conclusions: 1-yr survival rate =50% may justify a phase III randomized trial. Survival data on 46 pts followed for =1 yr will be presented. OGX-011 is being developed by OncoGenex Technology Inc. + Isis Pharmaceuticals Inc.

No significant financial relationships to disclose.

The role of double-balloon enteroscopy in diagnosis and management of incomplete small-bowel obstruction

BACKGROUND AND STUDY AIMS

Double-balloon enteroscopy (DBE) is a newly developed endoscopic technique for investigating various small-bowel diseases. The aim of this study was to evaluate the diagnostic yield and therapeutic impact of DBE in patients with incomplete small-bowel obstruction (SBO).

PATIENTS AND METHODS

This study is a prospective analysis of 45 consecutive patients specifically referred to our hospital between December 2004 and January 2006 for investigation of incomplete SBO that had been confirmed by both clinical symptoms and imaging tests. Patients with a high suspicion of postoperative adhesion were excluded and DBE was performed in stable patients. The final management was guided by the results of DBE and radiographic studies. Demographic, clinical, procedural, and outcome data were collected for analysis.

RESULTS

A total of 30 DBEs were performed in 29 patients (11 women, 18 men; mean age 52.0 +/- 13.5 years). DBE identified causes of incomplete SBO in 27 patients (93.1%) and allowed histopathologic evaluation in 17 patients (58.6%). The more common abnormalities detected were small-bowel tumors (48.3%) and strictures caused by Crohn's disease (24.1%). In detecting small-bowel abnormalities, DBE showed a sensitivity of 96.4%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 50%. DBE influenced the therapeutic strategy in 41.4% of patients by adding more information regarding appropriate treatment. Follow-up data were obtained for 26 patients (89.7%), for a mean 9.4 months (range 4-18 months). Of the 26 patients with follow-up, 21 (72.4%) had no further SBO.

CONCLUSIONS

Double-balloon enteroscopy is a feasible diagnostic tool for detecting the causes of incomplete SBO in patients without a history of abdominal surgery and also influences therapy in patients without a definite cause detected by conventional radiography.

Association of polymorphisms in the peroxisome proliferator-activated receptor gamma gene and osteoarthritis of the knee

OBJECTIVES

To study the association between two common polymorphisms in the peroxisome proliferator-activated receptor gamma (PPARgamma) gene and susceptibility to, and severity of, osteoarthritis in a French-Canadian population.

METHODS

Genomic DNA was obtained from 172 patients with osteoarthritis and 210 ethnically matched healthy controls. Genotyping for the polymorphisms in the PPARgamma gene (Pro12Ala and C1431T) was carried out using polymerase chain reaction-restriction fragment length polymorphism. The standard Kellgren-Lawrence grading score and the French version of the Western Ontario and McMaster Universities Osteoarthritis Index were used to assess the radiological and functional severity of the disease. Estimated haplotypes were generated using the expectation maximisation algorithm. Genotype and allele frequencies were analysed using the chi2 test.

RESULTS

Genotype and allele frequencies for either polymorphism in the PPARgamma gene did not differ significantly between patients with osteoarthritis and controls. Moreover, no significant differences were observed after stratification of patients according to age at disease onset, radiological or functional severity. Similarly, haplotype analysis of both polymorphisms in the PPARgamma gene showed no association of any haplotype with susceptibility to, or severity of, osteoarthritis.

CONCLUSION

These findings suggest that the examined polymorphisms in the PPARgamma gene do not contribute to susceptibility to, or severity of, osteoarthritis in the French-Canadian population.