Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach / Introdução do gene resistente à ferragem da folha bacteriana (BLB), xa7 na variedade MARDI elite, MR219 por abordagem de backcrossing assistida por marcador (MABC)

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

Rapid detection of Salmonella Typhi by loop-mediated isothermal amplification (LAMP) method

An in-house loop-mediated isothermal amplification (LAMP) reaction was established and evaluated for sensitivity and specificity in detecting the presence of Salmonella Typhi (S. Typhi) isolates from Kelantan, Malaysia. Three sets of primers consisting of two outer and 4 inner were designed based on locus STBHUCCB_38510 of chaperone PapD of S. Typhi genes. The reaction was optimised using genomic DNA of S. Typhi ATCC7251 as the template. The products were visualised directly by colour changes of the reaction. Positive results were indicated by green fluorescence and negative by orange colour. The test was further evaluated for specificity, sensitivity and application on field samples. The results were compared with those obtained by gold standard culture method and Polymerase Chain Reaction (PCR). This method was highly specific and -10 times more sensitive in detecting S. Typhi compared to the optimised conventional polymerase chain reaction (PCR) method.

Blood Lipid Profile in Acute Coronary Syndrome and Chronic Stable Angina Patients.

This study was designed to compare the blood lipid profile and conventional cardiovascular risk factors in patients with acute coronary syndrome (ACS) and chronic stable angina (CSA). A total of 110 patients, 55 of which were of ACS and 55 with chronic stable angina (CSA) who underwent coronary angiography in the Department of Cardiology, BSMMU, Dhaka were enrolled for the study. Lipid profile and age, sex, diabetes mellitus, hypertension, hyperlipidemia, smoking habit, family history of premature coronary artery diseases (CAD) of the patients were recorded and compared. Mean±SD age of the studied patients was 52.2±10 years. Prevalence of diabetes mellitus (p<0.05) and hypertension (p <0.05) was significantly higher in patients with CSA than that with ACS. Frequency of hyperlipidemia, smoking habit and family history of CAD was similar between groups. Patients with CSA had significantly higher triple vessel diseases (TVD) (p < 0.001) and significantly lower high-density lipoprotein cholesterol (HDLc) (p < 0.05) compared to that of patients with ACS. ACS patients had significantly higher single vessel diseases (SVD) (p <0.001) compared to that of CSA but the distribution of low-density lipoprotein cholesterol (LDLc), total cholesterol and triglycerides were variable between groups. This study showed that CSA patients had substantially higher frequency of having some CVD risk factors with alteration in certain lipid profile parameters and higher number of triple vessels disease than patients with ACS. This might aid in selecting appropriate criteria for angiographic evaluation and better management of patients with coronary artery diseases.

New Hope for Resistant Hypertention.

Hypertension is a major public health problem. Despite the increasing awareness of hypertension and its implications among patients and treating physicians, the prevalence of resistant hypertension remains high. Resistant hypertension define as blood pressure that remains elevated above treatment goals despite administration of an optimal three drug regimen that include a diuretic1 The prevalence of resistant hypertension is projected to increase, owing to the aging population and increasing trends in obesity, sleep apnea, and chronic kidney disease. It is estimated that at least 10% of all patients with hypertension are resistant to existing drugs. Management of resistant hypertension must begin with a careful evaluation of the patient to confirm the diagnosis and exclude factors associated with “pseudo-resistance,” such as improper BP measurement technique, the white-coat effect, and poor patient adherence to life-style and/or antihypertensive medications. Despite the use of the appropriate dose and type of diuretic to overcome the management of resistant hypertension, we can’t achieve our goal. But there is at least two devices namely Baroreflex Activation Therapy and Catheter-based renal sympathetic denervation make the new hope for the patient with resistant hypertension.

Extent of ST-Segment Depression Predicts In- Hospital Outcome in Non ST-Segment Elevation Acute Coronary Syndrome.

Background: The presence of ischemic ECG changes on admission has been shown to predict outcome, the relationship between the extent of ECG changes and the risk of cardiac events is still ill defined. The severity of ST-segment depression on admission ECG has a strong association with adverse in-hospital outcome in patients with non ST-segment elevation acute coronary syndrome. The study was done to observe the extent of ST-segment depression and in-hospital outcome in patients with non ST-segment elevation acute coronary syndrome. Methods: This study was conducted in the Department of Cardiology in NICVD Dhaka, from January 2006 to December 2007. Considering inclusion and exclusion criteria, a total of 183 patients were evaluated. All the patients were evaluated clinically after admission. ECG, blood biochemistry and echocardiography were done. Patients were categorized into three groups according to the extent of ST- segment depression. Results: In this study, analysis of the baseline parameters revealed no statistically significant difference among the three groups of patients (p>0.05). Mean sum of the ST-segment depression analysis was done and all mean values were more in group III patients. 41.0% patients developed complications during the study period. Acute LVF (22.9%) was the most common complication followed by arrhythmia (11.5%), cardiogenic shock (4.4%) and STEMI (2.2%). All the complications were more in group III patients. During this period 6% patients died and more death (12.3%) was observed in group III patients. Conclusion: The amount of ST-segment depression is a powerful predictor of adverse in-hospital outcome in patients with non ST-segment elevation acute coronary syndrome.

Early Risk Assessment In Right Ventricular Infarction By TIMI Risk Score.

Background: Inferior myocardial infarction complicated by right ventricular infarction is associated with a greater risk of in-hospital mortality and cardiovascular related complications. Early risk stratification of patients with right ventricular infarction is crucial for appropriate management and reduction of adverse cardiac events. The development of TIMI risk score has provided a useful tool to quickly and easily stratify patients with right ventricular infarction. We conducted this study to evaluate the prognostic value of TIMI Risk Score analysis in patients with right ventricular infarction. Methods: This observational study was conducted in the department of Cardiology in NICVD, Dhaka, from July 2006 to June 2008. Considering inclusion and exclusion criteria, a total of 60 patients with right ventricular infarction were evaluated. All the patients were evaluated clinically and ECG was done after admission. Patients were categorized into two groups by TIMI risk scoring. Patients with low TIMI risk score(0-3) were in Group-I and patients with high TIMI risk score(4- 14) were in Group-II. Results: The study revealed no statistically significant difference among the patients of two groups (p>0.05) in relation to sex, weight, risk factors and presenting complaints. Analysis revealed statistically significant difference among the patients of two groups (p<0.05) in relation to age, duration of chest pain, clinical parameters, Killip class of heart failure and LVEF. Regarding inhospital outcome, 51.7% patients developed complications during the study period and all the complications were more in group II patients with high TIMI risk score(4-14). Death (18.3%) was the most common complication followed by cardiogenic shock (15.0%), complete heart block(6.6%),cardiac arrest(6.6%),VT(3.3%)and 2nd degree heart block(1.6%). Conclusion: This study indicates that on admission - TIMI risk score analysis can identify patients with right ventricular infarction at higher risk for in-hospital mortality and morbidity.

Relationship between Baseline White Blood Cell count and C-reactive protein with Angiographic severity of Coronary Artery Disease in Patients with Acute Coronary Syndrome.

Inflammation has been shown to play a role in atherosclerosis and acute coronary syndrome. This study was carried out to evaluate the relationship between baseline white blood cell (WBC) count and C-reactive protein (CRP) with angiographic severity of coronary artery disease in patients with acute coronary syndrome and to identify those subsets of patients with acute coronary syndrome who may need to undergo invasive or conservative strategies. Method: A total of 100 patients with acute coronary syndrome including unstable angina, non-ST elevated myocardial infarction & ST elevated myocardial infarction were evaluated in National Institute of Cardiovascular Disease (NICVD), Dhaka with a view to correlate angiographic findings, C-reactive protein and WBC count. Results: This study observed that either raised WBC count or raised CRP independently and combination of both WBC count and CRP elevation were significantly associated with more severe coronary artery disease. Either raised WBC count or raised CRP or combination of raised WBC count and CRP were significant predictor of multivessel disease and high stenosis score. Conclusion: Elevation of WBC count and CRP in patients with acute coronary syndrome are associated with severe coronary disease. WBC count and CRP can be used as a new and even simpler tool for risk stratification in acute coronary syndrome.

A Case of Severe Tricuspid Stenosis of Rheumatic Origin.

Tricuspid valve stenosis is a valvular heart disease which results in the narrowing of the orifice of the tricuspid valve of the heart. It’s relatively a rare condition. It is almost always caused by rheumatic fever and is generally accompanied by mitral stenosis.Other rare causes include carcinoid syndrome, endocarditis, endomyocardial fibrosis, lupus erythematosus, right atrial myxoma and congenital tricuspid atresia. Here we describe a patient with history of prior CMC presented with severe Tricuspid Stenosis with Tricuspid Regurgitation (Grade-IV), Mitral Restenosis (Severe), Mitral Regurgitation (grade-1+), Aortic Stenosis (Mild) and Aortic Regurgitation (Grade-2).

In Hospital Outcome of Myocardial Infarcton in Nondiabetic Patients with High on Admission Blood Glucose Level.

Background: Patients without a history of diabetes often develop hyperglycemia during an acute coronary syndrome (ACS). Our aim was to evaluate the impact of admission hyperglycemia on in hospital outcome of non-diabetic patients admitted for acute coronary syndromes. Methods: The retrospective study was conducted in National Institute of Cardiovascular Diseases among the patients with acute myocardial infarction without history of diabetes. 50 patients with ST elevation MI (STEMI) with complications, 50 patients with STEMI without complications, 50 patients with non-ST elevation MI (NSTEMI) with complications and 50 patients without complications were included in the study. Every patient got the treatment as per protocol of the institute. On admission blood glucose of the patients was recorded. Level of blood glucose was correlated with the frequency of complications. Results : Average on admission blood sugar level was higher in patients who developed complications with STEMI (11.4 vs 8.78 mmol/L). On admission blood sugar level was also significantly higher in patients with NSTEMI with complications (10.6 vs 8.6 mmol/L). The frequency of individual complications had no significant relation with the blood sugar level. Conclusion : Higher level of admission blood glucose is related to poor in hospital outcome in both STEMI & NSTEMI even in nondiabetic patients. It may be used as a predictor of poor outcome of patients with myocardial infarction.

Coronary Angiographic Patency in Patients With Acute Myocardial Infarction With or Without Thrombolytic Therapy.

Background: The myocardial infarction (MI) is a leading cause of morbidity and mortality in developed countries as well as in developing countries including Bangladesh. Streptokinase since its introduction has been shown to reduce mortality significantly. The outcome of MI treated with streptokinase can be evaluated either by CAG measurement of TIMI blood flow or by the measurement of ST segment resolution in 12 lead ECG. Methods: This cross sectional comparative study was conducted in the department of Cardiology in Sylhet M A G Osmani Medical college, to compare the patency between MI patients with or without streptokinase therapy, from Jan 2008 to Dec 2009. Considering enrollment criteria a total of 96 patients with acute MI were evaluated. All patients were categorized into two groups. Group-I (n=48), who received streptokinase and Group-II (n=48), who did not received the same(due to late presentation). CAG was done with in 7- 28 days of on set of pain. The patients admitting in coronary care unit with the diagnosis of STEMI were taken as the study subjects. Results: Adequate TIMI (thrombolysis in myocardial infarction) flow was higher who received streptokinase (85.4%) than those who did not receive the therapy (52.1%). Conclusion: This study indicates that streptokinase therapy is associated with rapid and sustained reperfusion of the infarct related artery in the treatment of acute myocardial infarction.

Foreign Body Removal from Left Atrium following Successful PTMC – A Case Report.

With the advent of new technology and hardware. Percutaneous transluminal Mitral Commissurotomy (PTMC) is a safe procedure now-a-days. But it is still a costly procedure for the patients of develops countries like Bangladesh. So, the balloon and hardware is still practiced in some countries. One of the possible but rare complication of reuse in trained cover of the guide wire. We are reporting a case of retained cover of guide wire in LA during PTMC. It was successfully renounced wing a name.

Infective Endocarditis by Pseudomonas Species Following Percutaneous Transluminal Mitral Commissurotomy.

Infective mitral valve endocarditis developed in a 35-year-old male patient after a percutaneous transvenous mitral commissurotomy (PTMC). The echocardiogram demonstrated vegetation in the anterior leaflet of the mitral valve and blood culture showed growth of Pseudomonas species which was sensitive to Ceftazidime, Ciprofloxacin, Cotrimoxazole and Imipenem and resistant to Amikacin, Ceftriaxone, Gentamycin and Nitilmycin. The patient underwent treatment with intravenous ceftazidime and ciprofloxacin for six weeks and patient improved significantly and got cure of the disease. Infective mitral valve endocarditis should be recognized as a potentially lethal complication after PTMC. The important measures to prevent bacteremia during PTMC and the appropriate role of antibiotics and operation are discussed

Clinical profile and predisposing factors of cerebral palsy.

This was an analysis of one hundred ten children with cerebral palsy (CP) attending at the Child Development & Neurology Care Center of Dhaka Medical College Hospital during January 2002 to December 2003. These children were observed to study their clinical profile, etiological factors and associated problems. The mean age of these children was 2.9 +/- 2.9 years, mostly being males (n=79, 71.8%). Most of the families of these children belonged to poorer socioeconomic strata. Spastic diplegia constituted the predominant group (34.5 per cent), followed by spastic quadriplegia (25.5 per cent). Dyskinetic CP was present in 15.5 percent of the cases. Hypotonic CP constituted a significant proportion of cases. Delayed Motor Function was observed in all 110 cases, delayed speech was complained in 67.3% cases and impaired hearing was identified in 26.8% CP children. Mothers of 43.6% CP cases reported that they had prolonged labour during delivery and almost one third (29.1%) had suffered from pre-eclampsia or eclampsia. Majority (53.6%) of the CP cases were reported to have had perinatal asphyxia. Comprehensive assessment and early management of these problems are emphasized, which can minimize the extent of disabilities. By proper perinatal care, CP can be prevented.

Studies on virulence determinants of Plesiomonas shigelloides.

Virulence determinants of nineteen strains of Plesiomonas shigelloides isolated from stool samples of diarrhoeal children were studied. Heat-labile toxin was detected in seven strains using rat ileal loop model and in none of the strains using Chinese hamster ovary cell assay system and by Enzyme-linked immunosorbent assay. Rat ileal loop model was used for the first time to assay toxin in P. shigelloides and is suggested to be a cheap and effective method of detecting labile toxin in the organism. Heat stable toxin, cytotoxin, hemolysin and hemagglutinin were not detected in the strains tested. Invasiveness could not be established by using HEp-2 cell assay system. The results of this study provide some experimental support for an etiological role for P. shigelloides in the production of diarrhoea.

Corneal vital staining with gentian violet.

We have used 0.5% gentian violet solution as a corneal vital stain in 112 patients with variable degrees of corneal involvements and in 40 normal eyes as control. Gentian violet stained the epithelial defects and degenerated epithelial cells of cornea. The stain persisted 3-5 minutes and disappeared by 8-10 minutes. There was no cross infection from dye use. The dye did not hamper usual process of repair of corneal lesions. It is found highly feasible, with a sensitivity about 100% and specificity about 95%, with some minor side effects. Thus it could be an excellent method in community ophthalmology for early diagnosis of corneal affections, thereby commencing prompt and appropriate treatment in early stage.