Molecular mapping of quantitative trait loci for drought tolerance in maize plants.

Drought tolerance is one of the most important but complex traits of crops. We looked for quantitative trait loci (QTLs) that affect drought tolerance in maize. Two maize inbreds and their advanced lines were evaluated for drought-related traits. A genetic linkage map developed using RFLP markers was used to identify QTLs associated with drought-related traits. Twenty-two QTLs were detected, with a minimum of one and a maximum of nine for drought-related traits. A single-QTL was detected for sugar concentration accounting for about 52.2% of the phenotypic variation on chromosome 6. A single-QTL was also identified for each of the traits root density, root dry weight, total biomass, relative water content, and leaf abscisic acid content, on chromosomes 1 and 7, contributing to 24, 0.2, 0.4, 7, and 19% of the phenotypic variance, respectively. Three QTLs were identified for grain yield on chromosomes 1, 5, and 9, explaining 75% of the observed phenotypic variability, whereas four QTLs were detected for osmotic potential on chromosomes 1, 3, and 9, together accounting for 50% of the phenotypic variance. Nine QTLs were detected for leaf surface area on chromosomes 3 and 9, with various degrees of phenotypic variance, ranging from 25.8 to 42.2%. Four major clusters of QTLs were identified on chromosomes 1, 3, 7, and 9. A QTL for yield on chromosome 1 was found co-locating with the QTLs for root traits, total biomass, and osmotic potential in a region of about 15 cM. A cluster of QTLs for leaf surface area were coincident with a QTL for osmotic potential on chromosome 3. The QTLs for leaf area also clustered on chromosome 9, whereas QTLs for leaf abscisic acid content and relative water content coincided on chromosome 7, 10 cM apart. Co-location of QTLs for different traits indicates potential pleiotropism or tight linkage, which may be useful for indirect selection in maize improvement for drought tolerance.

Early renal damage assessed by the SLICC/ACR damage index is predictor of severe outcome in lupus patients in Pakistan.

We investigated patients with systemic lupus erythematosus with the objective of assessing whether early damage accrued in systemic lupus erythematosus as measured by the SLICC/ ACR Damage Index predicts mortality in lupus patients that have been followed prospectively in a single center. Patients with systemic lupus erythematosus from Aga Khan University hospital presenting between 1992 and 2007 were included. This enabled all patients to be potentially followed for at least 10 years. Yearly SLICC/ACR Damage Index scores were determined for each patient. Early damage was defined as a score ≥1, and no damage as a score of 0 at the initial assessment. Kaplan-Meier and Log rank tests were used to compare the survival experience between those with and without damage, with all patients being assessed at 10 years. In this inception cohort 198 patients were identified and were followed for 10 years. Of these, 47 (23.7%) patients had a SLICC/ACR Damage Index score of 0 (no damage) while 151 patients (76.3%) had at least one SLICC/ACR Damage Index item scored (early damage). Mean renal damage score at 1, 5 and 10 years was 0.16, 0.34 and 0.67, respectively. Of lupus patients who exhibited renal damage at their first SLICC/ACR Damage Index assessment, 31% died within 10 years of their illness as compared with only 13% who had no early renal damage (p < 0.003). Mean renal damage score at 1 year after diagnosis was a significant predictor of death within 10 years of diagnosis (p < 0.002).

Survival analysis and prognostic indicators of systemic lupus erythematosus in Pakistani patients.

To aim of this study is to analyse the survival rate and prognostic indicators of systemic lupus erythematosus (SLE) in Pakistani population. A total of 198 patients with SLE diagnosed between 1992 and 2005 were reviewed retrospectively. Clinical features at presentation, subsequent evolving features, autoantibody profile, damage scores and mortality data were obtained. Prognostic factors for survival were studied by statistical analysis. Of 198 SLE patients studied, 174 were women and 24 were men. The women to men ratio was 7.2:1. Mean age at presentation was 31 years (range 14-76). Mean duration of symptoms before diagnosis was 2.8 years. Mean duration of follow-up was 34.21 months (+/-33.69). Mean disease duration was 15.6 years. At diagnosis, arthritis, malar rash, oral ulcers and alopecia were the commonest features. During the follow-up, the prevalence of nephritis, arthritis, neurological and hematological disease increased significantly. About 76% (n = 151) of the patients had organ damage at the time of data analysis, and renal disease was the commonest cause. Univariate analysis revealed that renal disease (P = 0.000), seizures (P = 0.048), pleural involvement (P = 0.019), alopecia (P = 0.000) and discoid lesions (P = 0.005) were predictors for damage. Multivariate model, however, revealed that only renal disease was independent risk factor for damage (P = 0.002). During the study period, 47 patients (24%) died (five due to disease-related complications and rest as a result of infections). The 3-, 5-, 10-, 15- and 20-year survival rates of our cohort were 99, 80, 77, 75 and 75%, respectively. Cox regression analysis revealed that renal involvement (P = 0.002) and infections (P = 0.004) were independent risk factors for mortality. The survival of our Pakistani SLE patients was significantly lower compared to that of the Caucasian series reported in last decade. Nephritis not only contributes to organ damage but also acts a major determinant for survival. Infection remains the commonest cause of death. Renal involvement and infections are independent risk factors for mortality. Judicious use of immunosuppressive agents is necessary to improve the short-term survival of lupus patients.

Systemic lupus erythematosus in Pakistan.

Clinical features of systemic lupus erythematosus (SLE) have been described from different geographical regions in the world, with some clinical differences among different racial groups. Although data on the characteristics of SLE in Pakistan is scarce, it is not uncommon in the South East Asian region. The purpose of this study was, therefore, to delineate the clinical pattern and disease course in Pakistani patients with SLE and to compare it with international data on lupus patients. A total of 196 patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatism Association admitted to the hospital between 1986 and 2001 were studied by means of a retrospective review of their records. Demographically, it was seen that SLE is a disease predominantly of females in their third decade, which is consistent with worldwide data. The mean age of presentation was 31 years (range 14-76) and the mean duration of follow up was 34 (4-179) months. Generally, there was less cutaneous (46%), arthritic (38%), serositis (22%) and renal involvement (33%) but more neuropsychiatric symptoms (26%) in our population. Eighty-six percent of patients were ANA positive, whereas anti dsDNA was positive in 74% of patients. Infections, renal involvement, seizures and thrombocytopenia were associated with poor prognosis (P < 0.05). This study is the first of its kind in Pakistan. The clinical and laboratory characteristics of SLE patients in our study place our population in the middle of a spectrum between the Caucasians and other Asian populations. It has shown that the clinical characteristics of SLE patients in this country may be different to those of its neighbors.

Cutaneous manifestations of systemic lupus erythematosus in Pakistani patients.

OBJECTIVE: Systemic Lupus Erythematosus (SLE) is an autoimmune process in which cutaneous lesions occur in majority of patients. This study from Karachi, Pakistan was conducted to determine the pattern and prevalence of such lesions in SLE in Pakistani patients. METHODS: One hundred ninety eight patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatology Association were examined between 1986 and 2001 for the presence of cutaneous manifestations. RESULTS: Skin changes noted were: noncicatricial diffuse alopecia (22%), malar rash (31%), mucosal lesions (20%), discoid eruptions (15%), photosensitivity (33%), vascular lesions (20%), pruritus (17%), and pigmentary changes (22%). Peripheral gangrene, chronic ulcers, Raynauds phenomenon, urticaria, chilblains, thrombophlebitis, palmar erythema, and erythema multiform were rare. Anti ANA and anti dsDNA were positive in 93% and 83% patients respectively. CONCLUSION: A different clinical pattern was noted in our patients than reported previously.

Addicted schoolchildren: prevalence and characteristics of areca nut chewers among primary school children in Karachi, Pakistan.

OBJECTIVES: To evaluate the habits of betel quid use and areca nut chewing among school-aged children in Karachi, Pakistan. Areca nut (betel nut) is chewed by itself, in various scented preparations, and in betel quid (containing betel leaf, areca nut, slaked lime, condiments, sweeteners and sometimes tobacco) in various parts of Pakistan and India. It is associated with carcinogenesis, foreign body aspiration in children and oral submucous fibrosis, and may aggravate asthma. METHODS: We selected a stratified random sample of 160 primary school children between 4 and 16 years of age in Baba Island, Karachi. RESULTS: Seventy-four per cent of the children (118/159) used areca nut and 35% (55/159) used betel quid daily. More boys chewed areca nut than girls (72% vs 30%). The proportion of areca nut users increased by grade (from 48% in first grade to 90% in fifth grade). Most areca users first tried it with a family member (42%) or a friend (26%), and most (68%) consumed three or more packets a day. Children with fathers with three or fewer years of education were more likely to use areca nut (OR 3.2; 95% CI 1.2-8.4), and children whose mothers helped with homework less likely (OR 0.5; 95% CI 0.2-0.91; P = 0.027) to use it. Boys (OR 6.6; 95% CI 2.3-18.7) and areca nut users (OR 8.8; 95% CI2.8-27.0) were more likely to use betel quid. CONCLUSION: To reduce the use of areca nut, the Pakistan Government should consider imposing taxes on it, limiting advertising and actively communicating its health risks to the public.