Education, socio-economic status and age-related macular degeneration in Asians: the Singapore Malay Eye Study

BACKGROUND/AIMS

Low socio-economic status is increasingly being identified as a risk marker for chronic diseases, but few studies have investigated the link between socio-economic factors and age-related macular degeneration (AMD). The present study aimed to assess the association between socio-economic status and the prevalence of AMD.

METHODS

A population-based cross-sectional study of 3280 (78.7% response rate) Malay adults aged 40-80 years residing in 15 south-western districts of Singapore. AMD was graded from retinal photographs at a central reading centre using the modified Wisconsin AMD scale. Early and late AMD signs were graded from retinal photographs following the Wisconsin grading system. Socio-economic status including education, housing type and income were determined from a detailed interview.

RESULTS

Of the participants, 3265 had photographs of sufficient quality for grading of AMD. Early AMD was present in 168 (5.1%) and late AMD in 21 (0.6%). After adjusting for age, gender, smoking, hypertension, diabetes and body mass index, participants with lower educational levels were significantly more likely to have early AMD (multivariate OR 2.2, 95% CI 1.2 to 4.0). This association was stronger in persons who had never smoked (multivariate OR 3.6, 95% confidence CI 1.4 to 9.4). However, no association with housing type or income was seen.

CONCLUSIONS

Low educational level is associated with a higher prevalence of early AMD signs in our Asian population, independent of age, cardiovascular risk factors and cigarette smoking.

Complement factor H polymorphisms, renal phenotypes and age-related macular degeneration: the Blue Mountains Eye Study

Complement factor H (CFH) is a key regulator of the alternative pathway of complement and its mutations have been associated with membranoproliferative glomerulonephritis type II, atypical hemolytic uremic syndrome and age-related macular degeneration (AMD), suggesting that alternative pathway dysregulation is a common pathogenetic feature of these ocular and renal conditions. In this study we tested the hypothesis that common CFH variants have a global role in renal function in the Australian population-based Blue Mountains Eye Study (BMES). We replicated the association of I62V with estimated glomerular filtration rate (GFR; P=0.017) and creatinine clearance (CRCL; P=0.015). The minor allele of I62V (G) was deleterious: adding one copy of the G allele decreased GFR/CRCL by approximately 0.98 ml min(-1) per 1.73 m(2) (95% confidence interval (CI): 0.97, 0.99). We also replicated the association of Y402H with AMD and provided an unbiased estimate of population attributable risk (PAR). The minor allele of Y402H (C) was deleterious: the odds ratio estimate of CC genotype compared to TT was 1.87 (95% CI: 1.44, 2.45). The PAR of the C allele was estimated as 0.22 (95% CI: 0.15, 0.28). In summary, in the BMES population we confirmed the association between I62V and renal function, as measured by the estimated GFR, plus the association of Y402H with both early- and late-stage AMD.

Low-dose haloperidol prevents post-operative nausea and vomiting after ambulatory laparoscopic surgery

BACKGROUND

We evaluated the prophylactic effect of low-dose haloperidol (1 mg) on post-operative nausea and vomiting (PONV) in women undergoing ambulatory laparoscopic surgery. Droperidol (0.625 mg) and saline were controls.

METHODS

One hundred and fifty women undergoing ambulatory laparoscopic surgery under general anaesthesia were enrolled in this randomized, double-blind, and placebo-controlled study. After tracheal intubation, the haloperidol group (n=50) received intravenous haloperidol (1 mg), the droperidol group (n=50) received intravenous droperidol (0.625 mg), and the saline group (n=50) received intravenous saline.

RESULTS

Haloperidol- and droperidol-group patients reported a lower incidence of PONV [24% and 23% vs. 49% (saline group); P<0.05] and requested fewer doses of rescue antiemetics [13% and 16% vs. 38% (saline group); P<0.05] during the first four post-operative hours. During the 24-h post-operative period, haloperidol- and droperidol-group patients also reported a lower incidence of PONV [31% and 32% vs. 62% (saline group); P<0.01]. No differences were found between the haloperidol and droperidol groups.

CONCLUSION

Like droperidol (0.625 mg), prophylactic intravenous haloperidol (1 mg) significantly reduced the incidence of PONV in women undergoing ambulatory laparoscopic surgery.

Population prevalence and incidence of Parkinson’s disease in an Australian community

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting older individuals. Few studies have determined the prevalence and incidence of this disease in Australia. The aim of the study was to estimate the prevalence and 10-year incidence of PD in the Australian community.

METHODS

In the Blue Mountains Eye Study (BMES), a population-based health survey of Australian residents aged 49 years or more, we determined the cross-sectional prevalence (BMES2, 1997-1999, n = 3509) and 10-year incidence (BMES1, 2 and 3, 1992-1994, 1997-1999 and 2002-2004, respectively, n = 2545) of PD. We screened participants who took PD medications. PD diagnosis was confirmed by contacting the participant's medical/general practitioners.

RESULTS

Nineteen new cases of PD were identified over the 10-year period, a 10-year incidence of 0.84% (95% confidence interval (CI) 0.54-1.33%). In the cross-sectional study, 16/3509 participants were confirmed to have PD (0.46%), with age-specific prevalence rates of 0.48% in persons aged 60-69 years, 0.82% for ages 70-79 years and 0.56% in persons aged 80 years or older. No PD cases were identified among participants less than 60 years of age. When age standardized to the 2001 Australian population, the prevalence of PD was 362 per 100,000 (95%CI 183-541) among persons aged 50 years or older and 104 per 100,000 for the Australian population at all ages, assuming no prevalent cases in persons aged less than 50 years.

CONCLUSION

This study estimates a 0.46% (95%CI 0.23-0.68) prevalence of PD patients treated with medications aged 50 years or older and a 10-year incidence of 0.84% (95%CI 0.54-1.33).

The metabolic syndrome and retinal microvascular signs in a Japanese population: the Funagata study

AIMS

To determine the relationship of metabolic syndrome and its components with retinopathy and other retinal microvascular signs in a Japanese population.

METHODS

The Funagata study recruited 1961 (53.3% of eligible) Japanese aged 35 or older. The metabolic syndrome was diagnosed primarily using definitions of the International Diabetes Federation. Retinopathy and retinal microvascular signs were assessed from fundus photographs. Retinal arteriolar and venular diameters were measured using a computer-assisted programme.

RESULTS

Data were available for analysis in 1638 persons for retinopathy and retinal microvascular signs and 921 persons for retinal vessel diameters. Various components of the metabolic syndrome were associated with retinal microvascular signs: a larger waist circumference was associated with wider venular diameter and retinopathy lesions; a higher blood pressure level was associated with focal arteriolar narrowing, arteriovenous nicking, enhanced arteriolar wall reflex and narrower arteriolar diameter; and a higher triglyceride level was associated with enhanced arteriolar wall reflex. Overall, persons with the metabolic syndrome were more likely to have retinopathy (odds ratio 1.64, 95% CI: 1.02 to 2.64) and wider venular diameter 4.69 microm (95% CI: 1.20 to 8.19 microm) than persons without the metabolic syndrome.

CONCLUSION

We report associations of metabolic syndrome components with retinopathy and wider venular diameter in Japanese adults. These data suggest that metabolic abnormalities, indicated by metabolic syndrome components, are associated with microvascular changes in the retina. There was no synergistic effect of the metabolic syndrome on retinal microvascular changes beyond its individual components.

The relationship of retinal vascular calibre to diabetes and retinopathy: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study

AIMS/HYPOTHESIS

The aim of the study was to examine the relationship of retinal vascular calibre with glucose intolerance, diabetes and retinopathy in a population-based cohort.

METHODS

The Australian Diabetes, Obesity and Lifestyle study recruited adults aged > or =25 years old from across Australia. Participants were classified using an oral glucose tolerance test as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), impaired fasting glucose (IFG), known diabetes or newly diagnosed diabetes. Digital retinal photographs were taken of all participants with diabetes, IGT and IFG, and a sample of those with NGT, and graded for the presence of retinopathy. Retinal vascular calibre was measured from photographs by a computer-assisted method.

RESULTS

Of the 1,998 participants with gradable retinal images, 16% had known diabetes, 17% newly diagnosed diabetes, 42% IGT, 6% IFG and 19% NGT. After multivariable adjustment, retinal arteriolar calibre was significantly larger in people with known diabetes (178.9 microm) compared with participants with NGT (174.6 microm, p = 0.02), IGT/IFG (175.5 microm, p = 0.02) or newly diagnosed diabetes (175.6 microm, p = 0.047). One SD increase in mean arteriolar calibre was associated with higher odds of diabetes compared with NGT (odds ratio [OR] = 1.28, 95%CI = 1.06-1.55). After multivariable adjustment, each SD increase in venular calibre was associated with higher odds of having retinopathy in persons with IGT/IFG (OR = 1.78, 95%CI = 1.36-2.34) or in persons with diabetes (OR = 1.68, 95%CI = 1.23-2.29).

CONCLUSIONS/INTERPRETATION

Diabetes is associated with larger retinal arteriolar calibre and retinopathy with larger retinal venular calibre. The contrasting associations may reflect different underlying pathophysiological processes in the natural history of diabetes.

Body mass index and its effects on retinal vessel diameter in 6-year-old children

PURPOSE

To examine the relationship between body mass index (BMI) and other anthropometric measures with retinal vessel diameter in children.

METHODS

A random cluster sample of 34 schools was selected in the Sydney metropolitan area during 2003-04, and 1740 children aged 6 years participated in The Sydney Childhood Eye Study. Retinal images were taken and vessel diameter was measured using a computer-imaging program. Anthropometric measures, including weight, height, waist circumference, BMI and body surface area (BSA), were obtained and defined using standardized protocols. Data on confounders, including ocular parameters, ethnicity, birth parameters and blood pressure, were similarly collected.

RESULTS

Mean BMI was 16.2 kg/m(2) (+/-2.1 s.d.) in 1608 (92.4%) children with complete data. After controlling for age, sex, ethnicity, axial length of the eyeball, birth weight and mean arterial blood pressure, children with BMI above the cardiovascular risk threshold (defined as BMI>16.1 kg/m(2) in boys and BMI>15.9 kg/m(2) in girls) had mean retinal venular diameter 2.1 microm larger than those with BMI below this threshold (P=0.026). Increasing weight and BSA were also positively associated with wider retinal venules. Children in the highest quartile of BMI had mean retinal arteriolar diameter 2.2 microm smaller than those in the lowest quartile. Increasing waist circumference and shorter height were also associated with narrower retinal arterioles.

CONCLUSIONS

In this sample of 6-year-old children, greater BMI, weight and BSA were associated with wider retinal venules, while greater BMI and larger waist circumference were associated with narrower retinal arterioles. These findings suggest a possible effect of increased body mass and adiposity on early microvascular structural alterations in childhood, long before the development of cardiovascular disease.

Sympathetic nerve activity and heart rate variability during severe hemorrhagic shock in sheep

INTRODUCTION

In this study we explored direct and indirect measures of autonomic nervous system function, as well as changes in cardiovascular complexity, during hemorrhagic shock (HS).

METHODS

HS was induced in anesthetized sheep (n=8) by removing 40 ml/kg of blood in four 10 ml/kg steps over 40 min. Resuscitation was performed with lactated Ringer's and re-infusion of shed blood. Renal sympathetic nerve activity (RSNA) was measured by microneurography. Spectral analysis of heart rate variability (HRV) employed fast-Fourier transformation of the R-to-R interval (RRI) of the EKG. This generated the normalized high-frequency (HFnu) and low-frequency (LFnu) powers of the RRI, and their ratio (LFnu/HFnu, a proposed index of sympatho-vagal balance). Additionally, non-linear methods were applied: RRI complexity was measured by approximate (ApEn) and sample (SampEn) entropy methods; RRI fractal dimension was measured by curve lengths (FDCL). Plasma catecholamines were determined by HPLC.

RESULTS

The model caused profound HS; 2/8 animals survived till the end of resuscitation. RSNA increased in 7/8 sheep and, as HS progressed, multiple burst complexes were identified followed by sympathetic withdrawal. Concomitant decreases in HFnu and increases in LFnu/HFnu occurred after 20 ml/kg blood loss. ApEn and FDCL decreased after withdrawal of 40 ml/kg of blood. Catecholamine concentrations increased throughout HS. LFnu/HFnu and RSNA were not linearly correlated.

CONCLUSIONS

HS led to an increase in RSNA with subsequent withdrawal. LFnu/HFnu increased during HS in association with vagal withdrawal and loss of RRI complexity. RRI complexity may in part reflect vagal modulation of the heart rate. Changes in directly measured tonic sympathetic traffic do not correlate with non-invasive measures of autonomic modulation of the heart.

Change in health-related quality of life after cataract surgery in a population-based sample

PURPOSE

To assess the long-term outcomes from cataract surgery on self-rated health, and health-related quality of life (HRQOL) in a population-based older sample.

METHODS

Participants of the Blue Mountains Eye Study at the baseline (n=3654), 5 (n=2335), and 10-year follow-up (n=1952) were interviewed and examined. Questionnaires included an assessment of self-rated health and HRQOL using the 36-item Short-Form Health Survey (SF-36). Incident cataract surgery was defined if participants had cataract surgery since baseline, and confirmed via lens photographic grading.

RESULTS

There was no statistically significant difference in the proportions of participants who experienced a change in self-rated health between those who had incident cataract surgery (14.1% improvement; 29.1% deterioration) and non-surgical subjects (16.7% improvement; 27.0% deterioration). We found no association between incident cataract surgery and the odds for 10-year change in self-rated health, after multivariate adjustment. In contrast, participants who had incident cataract surgery had a significant improvement in the mean scores of 'mental health' domain of HRQOL (+1.60 vs-2.04, P=0.02) and in the mental component score (+1.43 vs-0.82, P=0.02) than participants who did not undergo surgery. Cataract surgery during follow-up had no significant influence on change in mean scores of other domains or in their physical component score of the SF-36 (-2.57 in participants who had incident surgery vs-2.29 in non-surgical participants, P=0.78).

CONCLUSIONS

We confirmed long-term improvement following cataract surgery in the mental but not in the physical domain of the SF-36 or in answers to a specific self-rated health question.

Midazolam vs ondansetron for preventing postoperative nausea and vomiting: a randomised controlled trial

We compared the prophylactic anti-emetic efficacy of midazolam and ondansetron in 90 patients scheduled for minor gynaecological (hysteroscopy) or urological (ureteroscopy) procedures planned to last 1-2 h under sevoflurane anaesthesia with spontaneous ventilation of the lungs via a laryngeal mask airway. Midazolam 2 mg or ondansetron 4 mg were administered intravenously 30 min before the end of surgery. The proportions of patients who experienced postoperative nausea and vomiting in the first 24 h (30% and 27% for the midazolam and ondansetron groups, respectively) were similar in the two groups. The incidence of postoperative nausea and vomiting was significantly smaller in both groups than predicted according to the patients' underlying risks (midazolam group: p = 0.018; ondansetron group: p = 0.017). There were no significant differences in average sedation scores or pain scores. Treatment using ondansetron for anti-emetic prophylaxis did not provide a superior benefit compared to midazolam in the present study.

Five-year incidence and progression of diabetic retinopathy in a defined older population: the Blue Mountains Eye Study

AIMS

To determine 5-year incidence and progression of diabetic retinopathy in an older Australian population-based cohort.

METHODS

During the period 1992-1994, the Blue Mountains Eye Study examined 3654 residents aged 49+years (82.4% of those eligible), living in two urban postcode areas, west of Sydney, Australia. Participants were subsequently invited to attend 5-year follow-up exams. After excluding 543 (14.8%) who died during the follow-up period, 2334 persons (75.0%) were re-examined during 1997-1999. The examination included a comprehensive questionnaire, blood pressure measurement, standardised refraction, Zeiss stereo retinal photographs, and estimation of fasting blood glucose. Diabetic retinopathy was graded from the retinal photographs, using the modified Early Treatment Diabetic Retinopathy Scale classification (15-step scale).

RESULTS

Of participants with diabetes diagnosed at baseline, 150 were re-examined, including 139 with gradable fundus photographs. The cumulative 5-year incidence of diabetic retinopathy was 22.2% before 95% confidence interval (CI) 14.1-32.2%. Retinopathy progression (1+ steps) was documented in 25.9% (95% CI 18.8-34.0%) of participants with retinopathy and gradable photographs at both visits; in 58.3% of these cases, a 2+ -step progression was documented. Progression to proliferative retinopathy occurred in only 4.1% of those with retinopathy at baseline. The only baseline risk factors associated with retinopathy progression, after adjusting for age and gender, were increase in fasting blood glucose, odds ratio (OR) 1.2 (95% CI 1.1-1.4)/mmol/l, and increase in diabetes duration, OR 2.3 (95% CI 1.0-5.3)/10 years.

CONCLUSIONS

These data provide 5-year cumulative incidence of diabetic retinopathy in a defined older population. Increase in diabetes duration and elevated baseline fasting blood glucose level predicted retinopathy incidence.

Expression of matrix metalloproteinases of human lens epithelial cells in the cultured lens capsule bag

AIM OF PURPOSE: To observe the different expression of matrix metalloproteinases (MMPs) between pre- and postoperation of sham cataract surgery in vitrohuman lens capsule bag model from the same donor eye in order to investigate a possible role of MMPs in posterior capsule opacification (PCO).

METHODS

Sham cataract surgeries were performed in six human donor eyes. Immunohistochemical staining was used to detect the expression of MMP-2 and -9 of human lens epithelial cells (LECs) on the anterior capsulorhexis. LEC migration on posterior capsule of human lens from the same donor eye was observed in a modified capsule bag model without pin. Total MMP-2 and -9 protein production were determined by enzyme-linked immunosorbent assay at days 2, 10, 20, and 30 postoperation, respectively.

RESULTS

MMP-2 and -9 could not be detected immunohistochemically on the anterior capsulorhexis preoperation of cataract. Lens epithelia cells at the equator began to migrate by day 4. A confluent monolayer of lens epithelia cells was present on the posterior capsule at day 20. Total MMP-2 and -9 protein production increased with time with maximum levels reached on day 30.

CONCLUSION

MMP-2 and -9 were showed to be upregulated following sham cataract surgery. MMP expression could play an important role in PCO.

Has evidence changed practice?: appropriateness of carotid endarterectomy after the clinical trials

OBJECTIVE

To assess how appropriateness of and indications for carotid endarterectomy (CEA) have changed following the publication of several large international randomized controlled trials (RCTs) designed to rationalize use of CEA.

METHODS

The New York Carotid Artery Surgery Study (NYCAS) is a population-based cohort study of all CEAs performed on elderly patients from January 1998 through June 1999 in New York State. Detailed clinical data were abstracted from medical charts to assess indications for and appropriateness of surgery using a list of 1,557 indications for CEA developed by national experts using RAND appropriateness methods. Deaths and strokes within 30 days of surgery were ascertained and confirmed by two physicians.

RESULTS

Among the 9,588 patients, the mean age was 74.6 years and 93.6% had 70 to 99% carotid stenosis. Nearly three-quarters of patients (72.3%) underwent CEA for asymptomatic stenosis, 18.6% for TIA, and 9.1% for stroke. Overall, 87.1% of operations were done for appropriate reasons, 4.3% for uncertain reasons, and 8.6% for inappropriate reasons (vs 32% inappropriate before the RCTs, p < 0.0001). Among procedures judged inappropriate, the most common reasons were high comorbidity in asymptomatic patients (62.2%), operating after a major stroke (14.2%), or for minimal stenosis (10.5%). Among asymptomatic patients, those with high comorbidity had over twice the risk of death or stroke compared to those without high comorbidity (7.13% vs 2.69%, p < 0.0001).

CONCLUSIONS

Since publication of the randomized controlled trials, there has been a reduction in the proportion of patients undergoing carotid endarterectomy (CEA) for inappropriate reasons. The shift toward many asymptomatic patients undergoing CEA is concerning because the net benefit from surgery for these patients is low and is reduced further for patients with high comorbidity.

Ethnic differences in refraction and ocular biometry in a population-based sample of 11–15-year-old Australian children

PURPOSE

To examine the prevalence of refractive error and distribution of ocular biometric parameters among major ethnic groups in a population-based sample of 11-15-year-old Australian children.

METHODS

The Sydney Myopia Study examined 2353 students (75.3% response) from a random cluster-sample of 21 secondary schools across Sydney. Examinations included cycloplegic autorefraction, and measures of corneal radius of curvature, anterior chamber depth, and axial length.

RESULTS

Participants mean age was 12.7 years (range 11.1-14.4); 49.4% were female. Overall, 60.0% of children had European Caucasian ethnicity, 15.0% East Asian, 7.1% Middle Eastern, and 5.5% South Asian. The most frequent refractive error was mild hyperopia (59.4%, 95% confidence interval (CI), 53.2-65.6), defined as spherical equivalent (SE) +0.50 to +1.99 D. Myopia (SE-0.50 D or less) was found in 11.9%, 95% (CI 6.6-17.2), and moderate hyperopia (SE> or =+2.00 D) in 3.5%, 95% (CI 2.8-4.1). Myopia prevalence was lower among European Caucasian children (4.6%, 95% CI 3.1-6.1) and Middle Eastern children (6.1%, 95% CI 1.3-11.0) than among East Asian (39.5%, 95%, CI 25.6-53.5) and South Asian (31.5%, 95%, CI 21.6-41.4) children. European Caucasian children had the most hyperopic mean SE (+0.82 D) and shortest mean axial length (23.23 mm). East Asian children had the most myopic mean SE (-0.69 D) and greatest mean axial length (23.86 mm).

CONCLUSION

The overall myopia prevalence in this sample was lower than in recent similar-aged European Caucasian population samples. East Asian children in our sample had both a higher prevalence of myopia and longer mean axial length.

Selection of bacteria able to control Fusarium oxysporum f. sp. radicis-lycopersici in stonewool substrate

AIMS

Tomato foot and root rot (TFRR), caused by Fusariumoxysporum f. sp. radicis-lycopersici (Forl), is an economically important disease of tomato. The aim of this study was to develop an efficient protocol for the isolation of bacteria, which controls TFRR based on selection of enhanced competitive root-colonizing bacteria from total rhizosphere soil samples.

METHODS AND RESULTS

A total of 216 potentially enhanced bacterial strains were isolated from 17 rhizosphere soil samples after applying a procedure to enrich for enhanced root tip colonizers. Amplified ribosomal DNA restriction analysis, in combination with determination of phenotypic traits, was introduced to evaluate the presence of siblings. One hundred sixteen strains were discarded as siblings. Thirty-eight strains were discarded as potential pathogens based on the sequence of their 16S rDNA. Of the remaining strains, 24 performed equally well or better than the good root colonizer Pseudomonas fluorescens WCS365 in a competitive tomato root tip colonization assay. Finally, these enhanced colonizers were tested for their ability to control TFRR in stonewool, which resulted in seven new biocontrol strains.

CONCLUSIONS

The new biocontrol strains, six Gram-negative and one Gram-positive bacteria, were identified as three Pseudomonas putida strains and one strain each of Delftia tsuruhatensis, Pseudomonas chlororaphis, Pseudomonas rhodesiae and Paenibacillus amylolyticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

We describe a fast method for the isolation of bacteria able to suppress TFRR in stonewool, an industrial plant growth substrate. The procedure minimizes the laborious screens that are a common feature in the isolation of biocontrol strains.

Neuroendocrine actions and regulation of hypothalamic neuropeptide Y during lactation

The expression of neuropeptide Y (NPY) and its co-messenger, agouti-related peptide (AgRP), in arcuate neurons of the hypothalamus is increased during lactation in rats. Our research has been addressing the questions of the physiological actions of these peptides during lactation and the physiological signals associated with lactation that result in increased expression of their genes. Our studies indicate that NPY and AgRP exert pleiotropic actions during lactation that help integrate neuroendocrine regulation of energy balance with controls over anterior and posterior pituitary hormone secretion. Further, reciprocal signaling to the NPY/AgRP system by leptin and ghrelin is responsible for the changes in expression of these hypothalamic peptides in lactating animals, and thus, may contribute to regulation of food intake and the various neuroendocrine adaptations of lactation.

Study on the effects of mechanical pressure to the ultrastructure and secretion ability of mandibular condylar chondrocytes

During mandibular movement, condyle is subjected to repetitive compression and the mandibular condylar chondrocytes (MCCs) can detect and respond to this biomechanical environment by altering their metabolism. The present study was undertaken to investigate the effects of pressure to the ultrastructure, aggrecan synthesis, nitric oxide (NO) and prostaglandin F(1)alpha(PGF(1)alpha) secretion in MCCs. In vitro cultured rabbit MCCs were incubated and pressed under continuous pressure of 90kPa for 60min and 360min by hydraulic pressure controlled cellular strain unit. The ultrastructure, aggrecan mRNA expression, activity of nitric oxide synthase (NOS) and PGF(1)alpha secretion were investigated. Besides, nitric oxide inhibitor was used together with pressure to investigate the role of NO in mechanical effects. The appearance of MCC on TEM showed that after been pressed under 90kPa for 60min, the cellular processes became elongated and voluminous, together with aggrecan mRNA increasing. Under 90kPa for 360min, some of the cells showed distinct sign of apotosis and the aggrecan mRNA decreased. Pressure of 90kPa could cause increase of NOS activity and decrease of PGF(1)alpha composition. Inhibitor experiments indicated that pressure-induced upregulation of aggrecan mRNA and inhibition of PGF(1)alpha synthesis was partly mediated by NO. Continuous pressure could cause changes on the ultrastructure and function of MCC, as well as up-regulation of aggrecan synthesis, increase of NO secretion and decrease of PGF(1)alpha composition. NO was the upstream molecule, which mediated the response of aggrecan and PGF(1)alpha to mechanical pressure.

Predicting postoperative nausea and vomiting with the application of an artificial neural network

BACKGROUND

Several medications have proved to be useful in preventing postoperative nausea and vomiting (PONV). However, routine antiemetic prophylaxis is not cost-effective. We evaluated the accuracy and discriminating power of an artificial neural network (ANN) to predict PONV.

METHODS

We analysed data from 1086 in-patients who underwent various surgical procedures under general anaesthesia without antiemetic prophylaxis. Predictors used for ANN training were selected by computing the value of chi(2) statistic and information gain with respect to PONV. The configuration of the ANN was chosen by using a software tool. Then the training of the ANN was performed based on data from a training set (n=656). Testing validation was performed with the remaining patients (n=430) whose outcome regarding PONV was unknown to the ANN. Area under the receiver operating characteristic (ROC) curves were used to quantify predictive performance. ANN performance was compared with those of the Naïve Bayesian classifier model, logistic regression model, simplified Apfel score and Koivuranta score.

RESULTS

ANN accuracy was 83.3%, sensitivity 77.9% and specificity 85.0% in predicting PONV. The areas under the ROC curve follow: ANN, 0.814 (0.774-0.850); Naïve Bayesian classifier, 0.570 (0.522-0.617); logistic regression, 0.669 (0.623-0.714); Koivuranta score, 0.626 (0.578-0.672); simplified Apfel score, 0.624 (0.576-0.670). ANN discriminatory power was superior to those of the other predicting models (P<0.05).

CONCLUSIONS

The ANN provided the best predictive performance among all tested models.

Role of IL-17 and regulatory T lymphocytes in a systemic autoimmune disease

To explore the interactions between regulatory T cells and pathogenic effector cytokines, we have developed a model of a T cell–mediated systemic autoimmune disorder resembling graft-versus-host disease. The cytokine responsible for tissue inflammation in this disorder is interleukin (IL)-17, whereas interferon (IFN)-γ produced by Th1 cells has a protective effect in this setting. Because of the interest in potential therapeutic approaches utilizing transfer of regulatory T cells and inhibition of the IL-2 pathway, we have explored the roles of these in the systemic disease. We demonstrate that the production of IL-17 and tissue infiltration by IL-17–producing cells occur and are even enhanced in the absence of IL-2. Regulatory T cells favor IL-17 production but prevent the disease when administered early in the course by suppressing expansion of T cells. Thus, the pathogenic or protective effects of cytokines and the therapeutic capacity of regulatory T cells are crucially dependent on the timing and the nature of the disease.