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Fulltext Risk factors for hip fracture in Asian men and women: the Asian osteoporosis study

Lau EM, Suriwongpaisal P, Lee JK, Das De S, Festin MR, Saw SM, et al.

J. Bone Miner. Res., 2001 Mar;16(3):572-80.
PMID: 11277276 DOI: 10.1359/jbmr.2001.16.3.572

The objectives of the Asian Osteoporosis Study (AOS) were to determine risk factors for hip fracture in men and women in four Asian countries, that is, Singapore, Malaysia, Thailand, and the Philippines. A total of 451 men and 725 women (aged 50 years and over) with hip fractures were compared with an equal number of community controls. A standardized questionnaire was administered by interview. The following relative risks (RRs) were found in women and men by multiple logistic regression: dietary calcium intake < 498 mg/day, 2.0 for women (95% CI, 1.5-2.8) and 1.5 for men (95% CI, 1.0-2.2); no load bearing activity in the immediate past, 2.0 for women (95% CI, 1.4-2.7) and 3.4 for men (95% CI, 2.3-5.1); no vigorous sport activities in young adulthood, 7.2 for women (95% CI, 4.0-13.0) and 2.4 for men (95% CI, 1.6-3.6); cigarette smoking, 1.5 for men (95% CI, 1.0-2.1); alcohol consumption 7 days a week, 2.9 for women (95% CI, 1.0-8.6) and 1.9 for men (95% CI, 1.1-3.2); fell twice or more in the last 12 months, 3.0 for women (95% CI, 1.8-4.8) and 3.4 for men (95% CI, 1.8-6.6); a history of fractures after 50 years of age, 1.8 for women (95% CI, 1.1-2.9) and 3.0 for men (95% CI, 1.6-5.6); a history of stroke, 3.8 for women (95% CI, 2.0-7.1) and 3.6 for men (95% CI, 1.8-7.1); use of sedatives, 2.5 for women (95% CI, 1.0-6.3) and 3.0 for men (95% CI, 1.0-9.7); and use of thyroid drugs, 7.1 for women (95% CI, 2.0-25.9) and 11.8 for men (95% CI, 1.3-106.0). Women who were 1.56 m or taller had an RR of 2.0 (95% CI, 1.3-3.0) for hip fracture and men who were 1.69 m or taller had an RR of 1.9 (95% CI, 1.2-3.1) for hip fracture. Based on these findings, primary preventive programs for hip fracture could be planned in Asia.

Matched MeSH terms: Regression Analysis
Exercise-induced bronchoconstriction among Malay schoolchildren

Zainudin NM, Aziz BA, Haifa AL, Deng CT, Omar AH

Respirology, 2001 Jun;6(2):151-5.
PMID: 11422895

OBJECTIVE: Exercise-induced bronchoconstriction (EIB) may be demonstrated in 60-70% of asthmatic children in temperate climates. In areas of high humidity it is postulated to be low. The aim of the study was to determine the prevalence of EIB in a population of schoolchildren with wheezing, living in the humid tropical climate of Kuala Lumpur, Malaysia.
METHOD: We performed a cross-sectional study using the International Study of Asthma and Allergies in Childhood questionnaire to identify 7-12-year-old Malay children with asthma symptoms from a primary school in central Kuala Lumpur. Sixty-five of 76 children with 'ever wheeze' performed an exercise challenge test successfully in an uncontrolled environment. A random sample of 80 schoolchildren with no history of wheeze were similarly tested as controls. The relative humidity and temperature were recorded. A fall of > 15% was considered as clinically important.
RESULTS: The prevalence of EIB in schoolchildren with 'ever wheeze' was 47.7%. The prevalence of EIB in children with 'current wheeze' was 51.6%. The prevalence of EIB in controls was 7.5%. The relative humidity during the study ranged from 41 to 90%. There was no significant relationship between different humidity levels and EIB (P = 0.58, regression analysis).
CONCLUSION: This study demonstrates that EIB is present in asthmatic children despite the highly humid tropical environment.

Matched MeSH terms: Regression Analysis
Determinants of linear growth in Malaysian children with cerebral palsy

Zainah SH, Ong LC, Sofiah A, Poh BK, Hussain IH

J Paediatr Child Health, 2001 Aug;37(4):376-81.
PMID: 11532058

OBJECTIVE: To compare the linear growth and nutritional parameters of a group of Malaysian children with cerebral palsy (CP) against a group of controls, and to determine the nutritional, medical and sociodemographic factors associated with poor growth in children with CP.
METHODOLOGY: The linear growth of 101 children with CP and of their healthy controls matched for age, sex and ethnicity was measured using upper-arm length (UAL). Nutritional parameters of weight, triceps skin-fold thickness and mid-arm circumference were also measured. Total caloric intake was assessed using a 24-h recall of a 3-day food intake and calculated as a percentage of the Recommended Daily Allowance. Multiple regression analysis was used to determine nutritional, medical and sociodemographic factors associated with poor growth (using z-scores of UAL) in children with CP.
RESULTS: Compared with the controls, children with CP had significantly lower mean UAL measurements (difference between means -1.1, 95% confidence interval -1.65 to - 0.59), weight (difference between means -6.0, 95% CI -7.66 to -4.34), mid-arm circumference (difference between means -1.3, 95% CI -2.06 to -0.56) and triceps skin-fold thickness (difference between means -2.5, 95% CI -3.5 to -1.43). Factors associated with low z-scores of UAL were a lower percentage of median weight (P < 0.001), tube feeding (P < 0.001) and increasing age (P < 0.001).
CONCLUSION: A large proportion of Malaysian children with CP have poor nutritional status and linear growth. Nutritional assessment and management at an early age might help this group of children achieve adequate growth.

Matched MeSH terms: Regression Analysis
Predictive factors by multivariate analysis for colorectal cancer in Malaysian patients undergoing colonoscopy

Tan YM, Rosmawati M, Ranjeev P, Goh KL

J Gastroenterol Hepatol, 2002 Mar;17(3):281-4.
PMID: 11982698

BACKGROUND: The majority of colorectal cancers are still diagnosed in patients who present with symptoms especially in countries where colorectal screening programs are not practised. The aim of our study was to determine the predictive factors for colorectal cancer in patients referred for colonoscopy.
METHODS: A prospective study of 485 consecutive patients who underwent colonoscopy during a 22-month period was performed. All patients answered a detailed questionnaire. Indications for colonoscopy and the findings were recorded.
RESULTS: The mean age of the study population was 55.7 +/- 14.7 years. There were 221 (45.6%) males and 264 (54.4%) females. Sixty-five (13.4%) were Malays, 298 (61.4%) were Chinese and 112 (23.1%) were Indians. Multiple backward stepwise regression analysis revealed that independent predictors for colorectal cancer (odds ratio [95% CI]) were the presence of rectal bleeding (4.3 [4.0-8.0]) and iron deficiency anemia (4.0 [3.6-10.2]). In those aged 50 and over, male gender (4.5 [2.2-9.3]) and abdominal pain (3.1 [1.4-6.7]) were also significant positive predictors of cancer.
CONCLUSIONS: With the ever-increasing demand for gastrointestinal endoscopy, the appropriate utilization of colonoscopy is essential to afford prompt patient evaluation. Our study supports the need to prioritize the use of colonoscopy in patients with rectal bleeding and iron deficiency anemia. In the older patient where the background prevalence of colorectal cancer is higher, referral for colonoscopy is also justified.

Matched MeSH terms: Regression Analysis
Socioeconomic profile and nutritional status of children in rubber smallholdings

Marjan ZM, Kandiah M, Lin KG, Siong TE

Asia Pac J Clin Nutr, 2002;11(2):133-41.
PMID: 12074180

This paper will present the socioeconomic profile and nutritional status of children aged 1-6 years in the rubber smallholdings of Peninsula Malaysia. A total of 323 households were involved in this study. The sociodemographic data were obtained through interviews with heads of households using a set of questionnaires. Anthropometric measurements were taken from 506 children aged 1-6 years from these households. The weight and height of the children were compared with the reference values of the National Center for Health Statistics (NCHS) and the nutritional status was classified based on the recommendations of WHO. The average age of the fathers was 39.9+/-8.6 years and 34.4+/-7.0 years for the mothers. The mean household size was 6.67+/-2.27. The majority (49.7%) of the heads of households received 4-6 years of formal education and 7.9% received no formal education. Based on the monthly per capita income, 24.0% were found to be in the hardcore poor category, 38.3% fall into the poor category and 37.7% in the above poverty income group. The prevalence of stunting and underweight among children between the ages of 1-6 years were highest among children from the hardcore poor, followed by the poor category and above the poverty line income group. Wasting was present in all income groups, with a prevalence of 4.2% found among the hardcore poor, 9.4% among the poor group and 8.4% in the above poverty income group. The Pearson Product Moment Correlation showed significant relationships between household total income and height-for-age (r = 0.131, P = 0.05) and weight-for-age (r = 0.127, P = 0.05). There were also significant correlations between monthly per capita income with height-for-age (r = 0.16, P < 0.01) and weight-for-age (r = 0.13, P < 0.05). The acreage of land utilised was correlated with height-for-age (r = 0.11, P < 0.05), weight-for-age (r = 0.17, P < 0.05) and weight-for-height (r = 0.16, P < 0.05). However, stepwise multiple regression analysis indicated that the predictor of height-for-age was monthly per capita income (R2 = 0.03, P < 0.01) and acreage of land utilised was a predictor for weight-for-age (R2 = 0.03, P < 0.01) and weight-for-height (R2 = 0.01, P < 0.01). Because income and acreage of land utilised have been shown to be associated with nutritional status, it is recommended that intervention programs that focus on generation of income and diversification of land utilisation should be undertaken. A multidiscipline approach involving the family, community and government agencies should be applied to any type of intervention program.

Matched MeSH terms: Regression Analysis
Fulltext A study to identify environmental health indicators within the Langat basin ecosystem

Jamal Hisham Hashim, Ruzita Shariff, Dayang Aminah Ali, Mohd Hasni Jaafar, Mazlin Mokhtar

Malaysian Journal of Public Health Medicine, 2002;2(2):36-42.
MyJurnal

Indicators, whether referred to as ecological, biological or environmental, help us in assessing environmental conditions. Hypothetically, joint influences are predicted of the parameters associated with the number of water-borne, food-borne and vector-borne cases in study areas. Regression analysis of the dependent variables in water—borne diseases such as Cholera, Typhoid, Dysentery and Hepatitis indicated that the total coly°orm, fecal colform, residual chlorine, mean monthly rainfall and temperature influence almost hay of the cases in the 3 District of Serernban. Thus, coordinated monitoring of physical, chemical and biological parameters is needed to continue to build databases and to develop models integrating environnrental and social conditions, consequences and costs.

Matched MeSH terms: Regression Analysis
Truck driver fatigue risk assessment and management: a multinational survey

Adams-Guppy J, Guppy A

Ergonomics, 2003 Jun 20;46(8):763-79.
PMID: 12745978 DOI: 10.1080/0014013021000056980

As part of an organizational review of safety, interviews and questionnaire surveys were performed on over 700 commercial goods drivers and their managers within a series of related companies operating across 17 countries. The results examine the reported incidence of fatigue-related problems in drivers and their associations with near miss and accident experience as well as work and organizational factors. Experience of fatigue problems while driving was linked to time of day and rotation of shifts, though most associations were small. There were significant associations found between fatigue experiences and driver and management systems of break taking and route scheduling. The quantitative combined with qualitative information suggested that, where feasible, more flexible approaches to managing the scheduling and sequencing of deliveries assisted drivers in managing their own fatigue problems through appropriate break-taking. The results are interpreted within the overarching principles of risk assessment and risk control.

Matched MeSH terms: Regression Analysis
Racial background is a determinant factor in the maintenance dosage of warfarin

Gan GG, Teh A, Goh KY, Chong HT, Pang KW

Int J Hematol, 2003 Jul;78(1):84-6.
PMID: 12894858

Warfarin is a drug commonly used in the prevention of thromboembolic events. There have been reports suggesting that racial background may influence warfarin dose requirements. Malaysia is a multiracial country in which there are 3 major races, Malay, Chinese, and Indian. We examined 100 patients from our hospital on stable maintenance doses of warfarin, with international normalized ratio (INR) of 2.0 to 3.5. We found that the mean warfarin dose for Indian patients (n = 19) was 6.9 mg, for Chinese patients (n = 55) was 3.6 mg, and for Malay patients (n = 26) was 3.2 mg. The results showed that the Indian patients required a statistically significantly higher warfarin dose than did patients of the other 2 races (P < .0005). Age was also found to affect the daily warfarin maintenance dose.

Matched MeSH terms: Regression Analysis
Fulltext What are the clinical factors that affect quality of life in adult asthmatics?

Hooi LN

Med J Malaysia, 2003 Oct;58(4):506-15.
PMID: 15190625

A study was conducted to determine the clinical factors that affect the quality of life in adult asthmatics. As part of their routine follow-up visit, 399 patients completed the SF-36 quality of life questionnaire, had peak expiratory flow rate readings (PEFR) taken and were interviewed to determine current symptom severity. The grade of severity of asthma was verified by the consultant physician in-charge. The mean age of the patients was 41.8 years and 31.8% of the patients were men. Most of the patients were Malay (64.7%), 89% had at least secondary level education and the mean duration of asthma was 17.6 years. The majority of patients had moderate or severe disease (43.6% and 55.9% respectively). For asthmatics with moderate or severe symptoms of chest tightness and/or shortness of breath, all domains of SF-36 scored significantly lower than those with mild symptoms, with the exception of the domain bodily pain. Patients with moderate/severe cough recorded significantly lower scores than those with mild cough for all domains except for bodily pain and social functioning. Only the physical functioning, role physical, general health and role emotional scores were significantly worse in those with a consultant grade of severe asthma compared to those with mild/moderate asthma. Patients with PEFR < 80% predicted had lower scores for the domains physical functioning, role physical and general health than those with PEFR > or = 80% predicted, but the scores for the other domains were similar in both groups. Quality of life is significantly impaired in adult asthmatics with current respiratory symptoms. However, consultant grade of severity of asthma and PEFR readings do not affect quality of life scores as much.
Study site: Asthma clinics, hospitals, Malaysia

Matched MeSH terms: Regression Analysis
Age and sequence of eruption of permanent teeth in Kelantan, north-eastern Malaysia

Nizam A, Naing L, Mokhtar N

Clin Oral Investig, 2003 Dec;7(4):222-5.
PMID: 14648258

The aim of this study was to determine the age and sequence of eruption of permanent teeth, as well as gender differences, in children and adolescents in Kelantan, Malaysia. Cross-sectional data on permanent teeth eruption were collected by examining pre-school, primary and secondary school children of 5-17 years of age. The subjects were drawn by multistage random sampling from the school registers. There were 2,382 subjects in the sample, 1,062 boys and 1,320 girls. The data were subjected to probit regression analysis. The mean age of eruption of lower first molar was 6.0 (95%CI: 5.8, 6.2) years. The median age of eruption of each tooth was earlier in girls than in boys. Although the range of years during which the permanent teeth erupted was similar in both sexes, i.e. 6-12 years, the sequence of the tooth eruption differed. All mandibular teeth, with the exception of first and second premolars in both males and females, tended to erupt earlier than their maxillary counterparts. The findings seem to correspond to earlier studies done in the other parts of the world.

Matched MeSH terms: Regression Analysis
Fulltext Risk factors for anti tuberculous drugs induced hepatitis: a prospective survey from a chest clinic in a general hospital

Fauzi ARM, Shah A, Rathor MY, Satwi S

Med J Malaysia, 2004 Mar;59(1):72-7.
PMID: 15535339

A prospective survey on 14 consecutive cases with tuberculous drug induced hepatitis was done at our chest clinic in a state general hospital over a period of 15 months. There were 30 controls chosen randomly from the chest clinic register. The cases had lower mean body mass index (P<0.008), serum albumin (P<0.005) and higher serum globulin (P<0.04). Serum liver transaminases and total bilirubin rose significantly during the acute episode of drug induced hepatitis. Among the risk factors studied, only chronic hepatitis B carrier status was found to be more prevalent among the cases. There was one death (7.1%) over the whole study period.
Study site: Chest clinic, Hospital Tengku Ampuan Afzan (HTAA), Kuantan, Pahang, Malaysia

Matched MeSH terms: Regression Analysis
Fulltext Blood pressure in rural and urban adult healthy females of Jat Sikh community in Punjab, North India: an epidemiologic profile

Sidhu S, Badaruddoza, Kaur A

Med J Malaysia, 2004 Jun;59(2):233-41.
PMID: 15559175

Blood pressure readings were collected from 1042 adult females of rural and urban Jat Sikh community of Punjab, a north Indian State. Anthropometric measurements like height, weight and skinfold thickness were also collected. The difference between rural and urban females in systolic, diastolic and mean arterial blood pressure was found to be statistically significant. All anthropometric variables and age have a significant positive association with blood pressure. The effects of anthropometric variables on blood pressure were assessed simultaneously through stepwise multiple regression analysis. All 'F' ratios have been found highly significant (p < 0.001) among both rural and urban female population.

Matched MeSH terms: Regression Analysis
Fulltext Lipoprotein (A) levels in type 2 diabetic patients with diabetic retinopathy

Ergün UGO, Oztüzün S, Seydaoglu G

Med J Malaysia, 2004 Aug;59(3):406-10.
PMID: 15727389

To examine a possible association between lipoprotein(a) [Lp(a)] levels and diabetic retinopathy in patients with type 2 diabetes mellitus. 100 type 2 diabetic patients were assessed with the following parameters: age, body mass index, duration of diabetes, blood pressure, fasting plasma glucose, total cholesterol, HDL-cholesterol, triglycerides, blood urea nitrogen, creatinine, Lp(a), and albumin excretion rate (AER). Retinopathy was classified as normal retina (NR), non-proliferative diabetic retinopathy (NPDR), and proliferative diabetic retinopathy (PDR) by an ophthalmologist. The PDR group had higher cholesterol (t=-2.24, p<0.05) and creatinine (z=-2.547, p<0.05) levels than the NPDR group. The PDR group had a higher value of AER (z=-2.439, p<0.01) than the NR group. The possibility of developing diabetic retinopathy after 10 years of diabetes was found to be 6.5 fold high (OR; 6.57, 95% CI 1.74-24.79; p<0.05). The Lp(a) levels were similar in the patients with retinopathy and those without retinopathy. In the study, there was no evidence for a relationship between the serum Lp(a) levels and diabetic retinopathy in type 2 diabetic patients.
Study site: diabetic outpatient clinic at Haydarpasa Numune Education and Research Hospital in Istanbul, Turkey.

Matched MeSH terms: Regression Analysis
Quality of life in cadaver and living-related renal transplant recipients in Kuala Lumpur hospital

Chiu SF, Wong HS, Morad Z, Loo LH

Transplant Proc, 2004 Sep;36(7):2030-1.
PMID: 15518734

To examine the quality of life in cadaver (CAD) and living-related (LRRT) renal transplant recipients.

Matched MeSH terms: Regression Analysis
Hev b 5 and Hev b 13 as allergen markers to estimate the allergenic potency of latex gloves

Yeang HY, Arif SA, Raulf-Heimsoth M, Loke YH, Sander I, Sulong SH, et al.

J Allergy Clin Immunol, 2004 Sep;114(3):593-8.
PMID: 15356563 DOI: 10.1016/j.jaci.2004.05.039

BACKGROUND:
Sensitization to natural rubber latex has been linked to proteins from medical latex gloves. Various assays to estimate the amount of residual allergenic proteins extractable from latex gloves to assess their potential exposure hazard have inherent weaknesses.

OBJECTIVE:
This investigation was aimed at developing 2-site immunoenzymetric assays and identifying appropriate protein markers to assess the allergenic potential of latex gloves.

METHODS:
The presence of 6 latex allergens--Hev b 1, 2, 3, 5, 6, and 13--was measured in a cross-section of commercial latex medical gloves by using monoclonal and polyclonal antibody-based 2-site immunoenzymetric assays. The overall allergenic potential of these gloves was assessed by IgE-inhibition assay. Stepwise multiple regression analyses were performed to identify marker allergens that best explained the variation in latex glove allergenicity.

RESULTS:
All 6 latex allergens were detected in at least some of the glove samples. Hev b 5 and Hev b 13 were identified as the marker allergens that combined best to explain the variation in the glove allergenicity. The significant multiple correlation (R=0.855) between these 2 markers and glove allergenic potency forms the basis of an assay to gauge latex glove allergenicity.

CONCLUSION:
The overall allergenic potential of latex gloves can be estimated by using Hev b 5 and Hev b 13 as indicator allergens. The correlation between glove allergenicity and the level of these allergens was maintained for low-protein gloves (<200 microg/g). This estimation of glove allergenicity was superior to that obtained by using total protein readings.

Matched MeSH terms: Regression Analysis
Neural network classification of autoregressive features from electroencephalogram signals for brain-computer interface design

Huan NJ, Palaniappan R

J Neural Eng, 2004 Sep;1(3):142-50.
PMID: 15876633

In this paper, we have designed a two-state brain-computer interface (BCI) using neural network (NN) classification of autoregressive (AR) features from electroencephalogram (EEG) signals extracted during mental tasks. The main purpose of the study is to use Keirn and Aunon's data to investigate the performance of different mental task combinations and different AR features for BCI design for individual subjects. In the experimental study, EEG signals from five mental tasks were recorded from four subjects. Different combinations of two mental tasks were studied for each subject. Six different feature extraction methods were used to extract the features from the EEG signals: AR coefficients computed with Burg's algorithm, AR coefficients computed with a least-squares (LS) algorithm and adaptive autoregressive (AAR) coefficients computed with a least-mean-square (LMS) algorithm. All the methods used order six applied to 125 data points and these three methods were repeated with the same data but with segmentation into five segments in increments of 25 data points. The multilayer perceptron NN trained by the back-propagation algorithm (MLP-BP) and linear discriminant analysis (LDA) were used to classify the computed features into different categories that represent the mental tasks. We compared the classification performances among the six different feature extraction methods. The results showed that sixth-order AR coefficients with the LS algorithm without segmentation gave the best performance (93.10%) using MLP-BP and (97.00%) using LDA. The results also showed that the segmentation and AAR methods are not suitable for this set of EEG signals. We conclude that, for different subjects, the best mental task combinations are different and proper selection of mental tasks and feature extraction methods are essential for the BCI design.

Matched MeSH terms: Regression Analysis
Working memory and literacy as predictors of performance on algebraic word problems

Lee K, Ng SF, Ng EL, Lim ZY

J Exp Child Psychol, 2004 Oct;89(2):140-58.
PMID: 15388303 DOI: 10.1016/j.jecp.2004.07.001

Previous studies on individual differences in mathematical abilities have shown that working memory contributes to early arithmetic performance. In this study, we extended the investigation to algebraic word problem solving. A total of 151 10-year-olds were administered algebraic word problems and measures of working memory, intelligence quotient (IQ), and reading ability. Regression results were consistent with findings from the arithmetic literature showing that a literacy composite measure provided greater contribution than did executive function capacity. However, a series of path analyses showed that the overall contribution of executive function was comparable to that of literacy; the effect of executive function was mediated by that of literacy. Both the phonological loop and the visual spatial sketchpad failed to contribute directly; they contributed only indirectly by way of literacy and performance IQ, respectively.

Matched MeSH terms: Regression Analysis
Fulltext Quantification of dark adaptation dynamics in retinitis pigmentosa using non-linear regression analysis

Omar R, Herse P

Clin Exp Optom, 2004 Nov;87(6):386-9.
PMID: 15575812 DOI: 10.1111/j.1444-0938.2004.tb03099.x

PURPOSE: Non-linear regression analysis was used to determine dark adaptation indices in people with retinitis pigmentosa and in control subjects.
METHODS: Dark adaptation data were collected for 13 people with retinitis pigmentosa and 21 controls using the Goldmann-Weekers Dark Adaptometer. Data were analysed using an exponential non-linear regression model and dark adaptation indices derived. The results were compared to age-related values.
RESULTS: The mean cone threshold of the group with RP (4.73 +/- 0.19 log units) was significantly greater than that found in the control group (3.69 +/- 0.12 log units). The rate of cone dark adaptation in the RP group was not significantly different from that of the control group. The a break in the RP group (6.46 +/- 0.70 minutes) was delayed when compared to the control group (4.29 +/- 0.21 minutes) and the rate of rod dark adaptation in the RP group was slower (10 +/- 2 per cent per minute) than that of the control group (15 +/- 1 per cent per minute).
CONCLUSIONS: This study has shown that a relatively simple data analysis can provide a more quantitative and intuitive description of dark adaptation rates in people with retinal disease. This technique will enable more effective use of dark adaptometry as a supplement to objective electrophysiology, when monitoring people with retinitis pigmentosa.
Study site: Retinitis Pigmentosa Society of NSW, the National Foundation of Blind Citizens in New South Wales and the Low Vision Clinic of the School of Optometry University of NSW, Australia

Matched MeSH terms: Regression Analysis
Fipronil resistance in the diamondback moth (Lepidoptera: Plutellidae): inheritance and number of genes involved

Sayyed AH, Wright DJ

J Econ Entomol, 2004 Dec;97(6):2043-50.
PMID: 15666763

Bioassays (at generation 1, G1) using fipronil, spinosad, indoxacarb, and Bacillus thuringiensis toxins Cry1Ac and Cry1Ca with a newly collected field population of Plutella xylostella (L.) from farmers fields in the Cameron Highlands, Malaysia, indicated a resistance ratio of approximately 400-, 1,170-, 330-, 2,840-, and 1,410-fold, respectively, compared with a laboratory-susceptible population of P. xylostella (ROTH). At G3, the field-derived population was divided into two subpopulations, one was selected (G3 to G7) with fipronil (fip-SEL), whereas the second was left unselected (UNSEL). Bioassays at G8 found that selection with fipronil gave a resistance ratio of approximately 490 compared with UNSEL and approximately 770 compared with ROTH. The resistance ratio for fipronil, spinosad, indoxacarb, Cry1Ac, and Cry1Ca in the UNSEL population declined significantly by G8. Logit regression analysis of F1 reciprocal crosses between fip-SEL (at G8) and UNSEL indicated that resistance to fipronil in the fip-SEL population was inherited as an autosomal, incompletely recessive (D(LC) = 0.37) trait. At the highest dose of fipronil tested, resistance was completely recessive, whereas at the lowest dose it was incompletely recessive. A direct test of monogenic inheritance based on a backcross of F1 progeny with fip-SEL suggested that resistance to fipronil was controlled by a single locus. The fip-SEL population at G8 showed little change in its response to spinosad and indoxacarb compared with G1, whereas its susceptibility to Cry1Ac and Cry1Ca increased markedly over the selection period. This suggests that there may be some low level of cross-resistance between fipronil, spinosad, and indoxacarb.

Matched MeSH terms: Regression Analysis
Comparison studies on the percolation thresholds of binary mixture tablets containing excipients of plastic/brittle and plastic/plastic deformation properties

Amin MC, Fell JT

Drug Dev Ind Pharm, 2004;30(9):937-45.
PMID: 15554218

Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, Pmax, or compression susceptibility (compressibility), gamma, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20-30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.

Matched MeSH terms: Regression Analysis

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