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Zuberi FF, Khan JA. Prospective comparison of prediction rules of mortality risk for CAP in a developing country. Int J Tuberc Lung Dis 2008; 12:447-452. [PMID: 18371273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
SETTING Aga Khan University Hospital, Karachi, Pakistan. OBJECTIVE To prospectively compare 30-day mortality with CURB65 and CRB65 scores and the three mortality risk groups (low, intermediate and high) based on these scores in hospitalised patients with community-acquired pneumonia (CAP). DESIGN Longitudinal observational cohort study of adult in-patients fulfilling the definition of CAP between October 2006 and May 2007. RESULTS A total of 137 patients was included. The 30-day mortality was 13.1%. Areas under the receiver operating characteristic curve for CURB65 and CRB65 scores were respectively 0.863 and 0.835. Odds of death among patients in the high mortality risk group of CURB65 score was 15.4 and those of CRB65 was 11.1 compared with the low and intermediate mortality risk groups combined as reference. CURB65 and CRB65 scores classified 46% and 24.8% patients, respectively, into the low mortality risk group. Length of hospital stay increased with the CURB65 score-based mortality risk groups but not with those based on the CRB65 score. CONCLUSION CURB65 and CRB65 scores showed no significant difference in predicting 30-day mortality. Both scores, and the CURB65 score in particular, categorised reasonable proportions of patients into the low mortality risk group who could be discharged from the emergency room and managed as out-patients.
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Devkota P, Khan JA, Acharya BM, Pradhan NM, Mainali LP, Singh M, Shrestha SK, Rajbhandari AP. Outcome of supracondylar fractures of the humerus in children treated by closed reduction and percutaneous pinning. JNMA J Nepal Med Assoc 2008; 47:66-70. [PMID: 18709034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Supracondylar fractures of humerus in children are common injuries. Displaced fractures are inherently unstable. Conservative treatment results in malunion. Open reduction and internal fixation (ORIF) is more invasive and recovery is prolonged. From September 2004 to September 2005, 102 displaced supracondylar fractures of humerus, aged between one and half year to 13 years, were treated using close reduction and percutaneous Kirschner (K) wire fixation under c-arm fluoroscopy. Seventy nine patients were treated by cross K-wires and in twenty three cases lateral two K-wires were put. Above elbow plaster of paris back slab was applied in all cases for at least four weeks. Back slab, K-wires were removed after four weeks and elbow range of motion exercise was started. Results were analyzed using Flynn's criteria. All patients were followed up to 14th week postoperatively. In cross K-wire group(N=79) 70.8% had excellent, 22.7% good, 3.8% fair and 2.5% had poor results at eight weeks follow up which was improved to 91.1% excellent, 6.3 good, 1.2% fair and 1.26% poor results at 14 weeks follow up. In lateral K-wire group (N=23) 70% had excellent, 21.7% good, 4.3% fair and 4.3% had poor result at eighth week which was improved to 91.3% excellent, 4.3% good, 4.3% fair and no poor result at 14th week follow up. Eight patients got superficial pin tract infection and seven patients sustained ulnar nerve injury post operatively. We recommend this procedure for displaced supracondylar fractures in children as it is safe and cost effective procedure with acceptable complication rates.
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Jain SK, Khan JA, Mittal V, Kumar K, Venkatesh S, Jain DC, Lal S. Indian tick typhus mimicking as Rocky Mountain Spotted Fever: a case report. THE JOURNAL OF COMMUNICABLE DISEASES 2008; 40:83-85. [PMID: 19127676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Ganatra HA, Kalia S, Haque AS, Khan JA. Cigarette smoking among adolescent females in Pakistan. Int J Tuberc Lung Dis 2007; 11:1366-1371. [PMID: 18034960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
SETTING Tobacco use among adolescent females is gaining importance as they take up smoking in increasing numbers. Recent studies show that sex differences in tobacco use are disappearing and that tobacco companies are agressively targeting females in developing countries. OBJECTIVE To determine the factors influencing the use of cigarettes among female high-school students in Karachi, Pakistan, and hence to identify areas for future intervention. METHOD A two-stage cluster sample of 644 females was drawn from government and private schools in a locality in Karachi. A self-administered questionnaire was used for data collection. RESULTS The mean age was 15.29 years. The prevalence of ever-smokers was found to be 16.3%. Univariate analysis indicated that private school attendance, underage sale of tobacco at shops, tobacco use by family members and exposure to cigarette advertisements predicted smoking among girls. Knowledge assessment of the subjects showed that most girls had good knowledge about the hazards of smoking. CONCLUSION Our study has identified several risk factors for smoking among young girls. Appropriate interventions are needed in the form of public education programmes, effective anti-tobacco laws and stricter enforcement of existing laws to restrict the number of young female smokers.
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Khan JA, Bajracharya AR. Surgical treatment of isthmic spondylolisthesis with radicular pain in adults. JNMA J Nepal Med Assoc 2007; 46:170-174. [PMID: 18340368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
A common consensus has not yet been reached on surgical management of isthmic Spondylolisthesis especially regarding the optimal surgical procedure. This prospective study was carried to see the outcome of Posterolateral fusion with instrumentation without decompression. Eight consecutive patients, aged between 43 to 55 years, underwent primary surgery for isolated L4, L5 lumbar isthmic Spondylolisthesis of less than grade II that presented with radicular pain and exhibited instability on dynamic radiograph. The surgical procedure consisted of instrumentation with pedicle screws and rods (Moss Miami System) and posterolateral fusion in situ by placement of autogeneous bone graft, harvested from posterior iliac crest. Postoperatively Clinical and Radiological status were assessed and were graded according to Stauffer and Coventry method. The patients were followed up for one to three years. Radiological evidence of fusion was clearly evident by six months in all cases. Symptomatically all were relieved of radicular pain completely. One patient had recurrent backache due to causes unrelated to the illness of surgical procedure requiring occasional analgesic. No serious complication was encountered. This lead to conclusion that in adults of our population with low grade isthmic spondylolisthesis and radicular pain Instrumentation with Posterolateral fusion without decompression was sufficient to relieve symptoms.
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Nawaz H, Imam SZ, Zubairi ABS, Pabaney AH, Sepah YJ, Islam M, Khan JA. Smoking habits and beliefs of future physicians of Pakistan. Int J Tuberc Lung Dis 2007; 11:915-9. [PMID: 17705960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
OBJECTIVE To assess the habits, knowledge and attitudes towards smoking among Pakistani medical students. METHODS A cross-sectional study was conducted from March 2004 to July 2005 at three medical colleges using a World Health Organization (WHO) questionnaire. A total of 1,029 medical students participated in the study. RESULTS The prevalence of smoking was found to be 11.2%. Smoking was more prevalent among males, hostel residents and first year medical students. Almost half of the smokers had tried to quit smoking. A family member or a friend was considered to be the most likely person to help quit smoking. The majority believed that passive smoking was harmful to health and were generally supportive of legislative measures to reduce tobacco use, such as the restriction of smoking in public places and the prohibition of sale of tobacco to children. Lesser but significant numbers thought that there should be a complete ban on smoking advertisements and that the price of tobacco products should be increased. CONCLUSION The study shows a high prevalence of tobacco use in future physicians in spite of adequate knowledge about and a satisfactory attitude towards smoking.
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Husain SJ, Sadiq F, Zubairi AB, Khan JA. Massive unilateral chylous pleural effusion: a rare initial presentation of Behcet's disease. Singapore Med J 2006; 47:978-80. [PMID: 17075668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Pulmonary manifestations of Behcet's disease are not very common and usually include pulmonary artery aneurysms, central venous thrombosis, pneumonia and pleurisy. Chylothorax secondary to superior vena caval obstruction is a rare complication and has been reported in only a few cases. We report a case of a 24-year-old man presenting with massive chylothorax as the initial presentation of Behcet's disease that was successfully treated conservatively.
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Zubairi AB, Haque AS, Husain SJ, Khan JA. Foreign body aspiration in adults. Singapore Med J 2006; 47:415-8. [PMID: 16645693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Foreign body aspiration is not an uncommon problem, particularly in children, the elderly, and those with predisposing factors like neurological impairment. In adults, regional differences exist in the type of foreign body aspirated. We report four cases of foreign body aspiration in South Asian adults, three of which were related to the widespread habit of chewing stimulant seeds such as betel nuts (two) and tamarind seed (one). It is important for clinicians to maintain a high index of suspicion for the diagnosis of foreign body inhalation in the appropriate clinical setting. Bronchoscopy is necessary not only for the diagnosis but also for the removal of foreign body from the bronchial tree. Once the foreign body is removed, the improvement in symptoms is usually dramatic, making it rewarding for any physician to manage.
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Khan JA, Zahid S, Khan R, Hussain SF, Rizvi N, Rab A, Javed A, Ahmad A, Ait-Khaled N, Enarson DA. Medical interns knowledge of TB in Pakistan. Trop Doct 2005; 35:144-7. [PMID: 16105336 DOI: 10.1258/0049475054620770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Of 460 interns from five Pakistani teaching hospitals surveyed, only 22% correctly identified the estimated number of new TB cases in Pakistan. The majority (96%) knew that droplet infection was the usual mode of transmission. Only 38% considered sputum smears for acid-fast bacilli as the best test for diagnosis of pulmonary TB and 43.5% for follow-up during TB treatment. The recommended four-drug anti-TB regimen was prescribed by 56.5% in the initiation phase and the recommended two-drug combination in the continuation phase by 52%. Most interns (82%) were unable to identify a single component of directly observed treatment short course (DOTS) strategy. Our study reflects poor awareness of and low compliance to the World Health Organization/National Tuberculosis Programme guidelines among interns. For effective control of TB, immediate action to improve undergraduate and continuing medical education is essential, with special emphasis on national guidelines.
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Khan JA, Aslam F, Fatimi SH, Ahmed R. Cough, fever and a cavitary lung lesion--an intrapulmonary teratoma. J Postgrad Med 2005; 51:330-1. [PMID: 16388182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
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Khan FM, Husain SJ, Laeeq A, Awais A, Hussain SF, Khan JA. Smoking prevalence, knowledge and attitudes among medical students in Karachi, Pakistan. EASTERN MEDITERRANEAN HEALTH JOURNAL = LA REVUE DE SANTE DE LA MEDITERRANEE ORIENTALE = AL-MAJALLAH AL-SIHHIYAH LI-SHARQ AL-MUTAWASSIT 2005; 11:952-8. [PMID: 16761665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A survey of smoking prevalence and attitudes was made among medical students randomly selected from classes at the Aga Khan University, Karachi, Pakistan. Of 271 respondents, 14.4% were current smokers (22.0% male and 3.8% females) and 3.3% ex-smokers. A majority of students recognized the dangers associated with active as well as passive smoking although only 55% of current smokers planned to quit in the near future. Most smokers (96%) believed that they as well as other health professionals needed training on smoking cessation and 95% of all students believed that doctors should play a role model in smoking cessation by not smoking themselves. Specific training and counselling should be a part of the required curriculum at medical schools.
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Hussain SF, Omar MD, Arif H, Sameeruddin SR, Zubairi ABS, Khan JA. Trends in hospital-based management of acute asthma from a teaching hospital in South Asia. Int J Clin Pract 2005; 59:912-6. [PMID: 16033612 DOI: 10.1111/j.1742-1241.2005.00516.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The aim of this study is to evaluate the hospital-based management of acute asthma in south Asia and to compare practices over a 10-year period. Adult patients (n = 102) admitted at a teaching hospital with acute asthma were studied. Documentation of precipitating factors, family history and physical signs were inadequate in more than half of patients. Pulse oximetry was documented in 95 (93%) patients, but peak flow monitoring was performed only in 50 (49%) patients. Ten-year trend showed deterioration in history and physical examination skills, under use of peak flow readings, and poor pre-discharge instructions. Some aspects of improved care included frequent use of pulse oximeter, preference of inhaled over systemic bronchodilators and increased use of systemic steroids. Significant deficiencies were identified in hospital-based management of acute asthma. Most aspects of asthma care continued to fall short of asthma guidelines.
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Mekan SF, Saeed O, Khan JA. Invasive aspergillosis with polyarthritis. Fallbericht. Invasive Aspergillose mit Polyarthritis. Mycoses 2004; 47:518-20. [PMID: 15601460 DOI: 10.1111/j.1439-0507.2004.01031.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a case of septic arthritis of multiple joints in an 18-year-old male caused by Aspergillus fumigatus. His initial presentation was of low-grade fever followed by involvement of both knee and ankle joints. Later, there was also involvement of metacarpophalangeal joints. Diagnosis was based on biopsy and culture of the skin and joint lesions. The symptoms resolved readily under administration of itraconazole. We recommend that clinicians should be alerted of potential fungal etiology in cases of fever and chronic arthritis, which is unresponsive to conventional medical therapy.
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Hussain SF, Zahid S, Khan JA, Haqqee R. Asthma management by general practitioners in Pakistan. Int J Tuberc Lung Dis 2004; 8:414-7. [PMID: 15141731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
SETTING Teaching university hospital in Karachi, Pakistan. OBJECTIVES Asthma management guidelines have been developed to assist practising physicians in treating asthma patients. The objective of this study was to evaluate if the prescribing habits of practitioners in Karachi were consistent with the published asthma guidelines. DESIGN A questionnaire survey was conducted among practitioners attending a pulmonary continuing medical education (CME) programme. Three case scenarios of asthma were given, and the doctors were asked to write a prescription for each case. Doctors were asked about their views on inhaler therapy and dietary restrictions in asthma. RESULTS Of 120 doctors, 100 (83%) responded. Thirty different regimens of short acting beta2-agonist and 16 regimens of steroid therapy were prescribed by the practitioners. Only 35% of the doctors prescribed corticosteroids for persistent asthma symptoms. The great majority of doctors were not aware of treatment options for persistent symptoms despite the use of preventive therapy (8% prescribed long-acting beta2-agonists, 6% high-dose inhaled corticosteroids and 13% theophyllines). Misconceptions about inhaler therapy and diet were found in 20 and 50 doctors, respectively. CONCLUSION General practitioners in Pakistan did not follow asthma management guidelines. There was serious lack of knowledge about asthma medications coupled with misconceptions about inhaler therapy and dietary factors.
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Hussain SF, Irfan M, Abbasi M, Anwer SS, Davidson S, Haqqee R, Khan JA, Islam M. Clinical characteristics of 110 miliary tuberculosis patients from a low HIV prevalence country. Int J Tuberc Lung Dis 2004; 8:493-9. [PMID: 15141744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
SETTING A university teaching hospital in Karachi, Pakistan. OBJECTIVE To define the clinical characteristics and outcome of miliary tuberculosis (TB) patients from a low human immunodeficiency virus (HIV) prevalence country. DESIGN Review of adult miliary TB patients admitted between 1994 and 2001. Clinical characteristics of those dying from miliary TB were compared with those of the survivors. RESULTS Most of the 110 cases reviewed were middle aged or elderly, with a female preponderance. An underlying medical condition was present in 47%. Presenting symptoms were of several weeks' duration, and mostly constitutional (fever and weight loss). Common laboratory findings included anaemia (62%), lymphopaenia (71%), hyponatraemia (74%), elevated serum alkaline phosphatase (57%) and hypoalbuminaemia (92%). Typical miliary pattern was observed in 77% of radiographs. Sputum smear and culture were positive in respectively 36% and 52% of those tested. Biopsy was performed in selected patients. Mean hospital stay was 8.8 days, and mortality was 30%. Those who died were significantly older than survivors and had a more fulminant course. Presence of altered mental status, lung crackles, leucocytosis, thrombocytopaenia and the need for ventilation were associated with increased mortality. CONCLUSION Miliary TB carries a high mortality. It should be considered in patients who present with prolonged systemic symptoms. A positive TB culture or biopsy is needed to establish a diagnosis.
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Khan JA, Malik A. Tuberculosis in Pakistan: are we losing the battle? J PAK MED ASSOC 2003; 53:320-1. [PMID: 14558732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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Chatterjee S, Das S, Khan JA, Bhattacharya RN. An uncommon case of neck fistula. JOURNAL OF THE INDIAN MEDICAL ASSOCIATION 2003; 101:24, 26. [PMID: 12841503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Congenital fistulae of the neck are branchial in origin and of these 2nd arch fistula is by far the most common, 3rd and 4th arch fistulae being very rare. Here, a case of fistula present since birth and extending from the neck, near the midline to the alveololingual sulcus, considered very rare, is presented. The patient was a 32-year-old male having sticky discharge through an opening in the upper part of the neck. Examination revealed an opening of approximately 1 mm diameter about 1 cm to the left of the midline just above the hyoid bone. A sinogram revealed a fistulous linear tract communicating with the oral cavity. Surgery was undertaken and the fistulous tract was excised.
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Bhurgri Y, Pervez S, Usman A, Khan JA, Bhurgri A, Kasi Q, Kasi I, Rasool AG, Faridi N, Bhurgri H, Ajam A, Ajam A, Malik J, Hasan SH. Cancer patterns in Quetta (1998-1999). J PAK MED ASSOC 2002; 52:560-5. [PMID: 12627905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
INTRODUCTION Quetta, the capital of Baluchistan, is located at latitude 30.25; longitude 67.00. It has a population of 759,245; 425,474 males (56%) and 333,771 females (44%); Census 1998. The majority of residents are Persian or Baluchi speaking Baluchs. METHODOLOGY The cancer cases from Quetta reported to the Karachi Cancer Registry were reviewed. The data included cases from the Aga Khan University Hospital (AKUH), Pathology Department (Quetta collection point) and health care facilities in Karachi. The residents of Baluchistan were ascertained and cancer cases residents of Quetta identified with the help of recorded addresses and retraceable telephone numbers. RESULTS During a 2-year period, 1st January 1998 to 31st December 1999 the Karachi Cancer Registry received 1077 cancer notifications from Quetta. Approximately half the cases were registered from the AKUH Quetta collection point. Others were the referral patterns in Karachi. The age-standardized incidence rate (ASR) of cancer, all sites (1998-99) was 137.0 for males and 92.8/100,000 for females. The commonest cancer in the males and females was cancer of the esophagus (ICD-10 categories C15; males- ASR 25.5, 17.2%; females-ASR 23.4,23.1%). One ofthe highest in the world, for both genders. Incidence of cancer breast in the females (ICD-10 categories C50; ASR 11.8, 13.3%) was low. CONCLUSION The cancer data from Quetta is quite distinct from the cancer pattern of Karachi. It represents only a part of the cancer burden of Quetta; nonetheless it gives a glimpse into the cancer profile of Baluchistan. The high incidence of esophageal cancer indicates an extension of the geographical limits of the esophageal cancer belt.
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Abstract
The revised International Code of Virus Classification and Nomenclature [7] followed by the Seventh Report of the International Committee on Taxonomy of Viruses (ICTV) [9] have generated a lot of criticism [2,4-6]. The main causes of criticism are (i) use of monomials instead of non-latinized binomials, as has been practice for some time in the past, e.g., tobacco mosaic tobamovirus, tobacco ringspot nepovirus etc. (ii) in toto italicization of official virus names. Following the expression of different views among virologists on this issue, it is being debated and an opportunity has been provided for reconsideration of the revised ICTV code [1,8,10]. This note attempts to analyse the existing criticisms being raised and justifies the continuation of the present ICTV code.
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Khan JA, Siddiqui MK, Singh BP. The Association of Begomovirus with Bitter Melon in India. PLANT DISEASE 2002; 86:328. [PMID: 30818622 DOI: 10.1094/pdis.2002.86.3.328b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bitter melon, Momordica charantia (Cucurbitaceae), is a vegetable of nutritive and medicinal value that is cultivated throughout India and other tropical countries. In September 2001, a severe disease of bitter melon with virus-like symptoms was observed at Lucknow, India. Symptoms consisted of upward curling, shortening, and distortion of leaves. Diseased melon fruits were stunted and deformed. Disease incidence was as high as 100%. Whitefly (Bemicia tabaci) can transmit the associated virus from diseased bitter melon to Nicotiana tabacum cv. White burley. The development of leaf curl symptoms in N. tabacum indicated the pathogen could be a begomovirus. Total nucleic acids were extracted from diseased bitter melon leaves, and polymerase chain reaction (PCR) tests were performed. Three pairs of primers, AV494 and AC1048 (1), CL-CR/F2 and CL-CR/R2, CL/11F and CL10/R (2), specific to DNA-A of begomoviruses were used in PCR. Virus-specific DNA-A fragments of expected sizes were identified (≈0.5, 0.7 and 1.2 kb, respectively). The presence of a begomovirus in all PCR-amplified DNA fragments was confirmed by Southern hybridization. Cloned DNA-A fragments of Tomato leaf curl virus and Cotton leaf curl virus (both begomoviruses) cross-hybridized with the PCR products gave strong signals under high stringency conditions. These data suggest that a begomovirus is associated with this bitter melon disease. Watermelon mosaic 1 virus is the only virus previously reported to naturally infect bitter melon; however, this virus has not been identified in India. Bitter melon is also an experimental host of Ribgrass mosaic virus (genus Tobamovirus) and Trichosanthes mottle virus (genus Potyvirus). To our knowledge, this is the first report of the occurrence of begomovirus infecting bitter melon. References: (1) S. D. Wyatt and J. K. Brown. Phytopathology 86:1288, 1996. (2). X. Zhou et al. J. Gen. Virol. 79:915, 1998.
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Tricand de la Gôutte J, Khan JA, Vulfson EN. Identification of novel polyphenol oxidase inhibitors by enzymatic one-pot synthesis and deconvolution of combinatorial libraries. Biotechnol Bioeng 2001; 75:93-9. [PMID: 11536131 DOI: 10.1002/bit.1168] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The feasibility of enzymatic synthesis of combinatorial libraries using multifunctional starting materials [i.e., 2,4-dihydroxy-N-(2-hydroxyethyl)benzamide, 1; 4-hydroxyphenethyl alcohol, 2; 3,5-dihydroxybenzyl alcohol, 3; and 4-hydroxybenzyl alcohol, 4] with six vinyl esters, in a one-pot reaction, was investigated. Candida antarctica lipase was employed as a biocatalyst. The resulting 24-compound library contained all the expected species with no significant bias toward particular combinations of substrates. As expected, the library contained a substance(s) that showed significant inhibition of polyphenol oxidase, which was used as a model target. The deconvolution was accomplished via resynthesis of ten partial libraries, which were prepared with either an equimolar mixture of the four alcohols and a single vinyl ester, or a single alcohol and equimolar mixture of the activated esters. Analysis of the inhibition pattern observed with these partial libraries suggested that 4-hydroxybenzyl benzoate (4e) should be the most potent inhibitor. This conclusion was confirmed by the preparation and comparison of all 24 components of the initial library. Finally, it was shown that 4e was a competitive inhibitor of polyphenol oxidase, with a K(i) of 40 microM. This value compared favorably with a K(i) of 400 microM, which was determined for parent phenol 4.
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Khan JA, Kumar P, Srinivasan A, Singh TP. Protein intermediate trapped by the simultaneous crystallization process. Crystal structure of an iron-saturated intermediate in the Fe3+ binding pathway of camel lactoferrin at 2.7 a resolution. J Biol Chem 2001; 276:36817-23. [PMID: 11473113 DOI: 10.1074/jbc.m104343200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This is the first protein intermediate obtained in the crystalline state by the simultaneous process of Fe(3+) binding and crystal nucleation and is also the first structure of an intermediate of lactoferrin in the Fe(3+) binding pathway. Lactoferrin is an iron-binding 80-kDa glycoprotein. It binds Fe(3+) very tightly in a closed interdomain cleft in both lobes. The iron-free structure of lactoferrin, on the other hand, adopts an open conformation with domains moving widely apart. These studies imply that initial Fe(3+) binding must be in the open form. The protein intermediate was crystallized by the microdialysis method. The protein solution, with a concentration of 100 mg/ml in 10 mm Tris-HCl, pH 8.0, was loaded in a capillary and dialyzed against the same buffer containing 26% (v/v) ethanol placed in a reservoir. FeCl(3) and CO(3)(2-) in excess molar ratios to that of protein in its solution were added to the reservoir buffer. The crystals appeared after some hours and grew to the optimum size within 36 h. The structure was determined by molecular replacement method and refined to final R- and R-free factors of 0.187 and 0.255, respectively. The present structure showed that the protein molecule adopts an open conformation similar to that of camel apolactoferrin. The electron density map clearly indicated the presence of two iron atoms, one in each lobe with 4-fold coordinations: two by the protein ligands of Tyr-92(433) OH and Tyr-192(526) OH and two other coordination sites occupied by oxygen atoms of bidentate CO(3)(2-) ions leading to a tetrahedral intermediate. The CO(3)(2-) anion is stabilized through hydrogen bonds with the synergistic anion-binding site Arg-121(463) and with Ser-122 Ogamma in the N-lobe and Thr-464 Ogamma in C-lobe. The third oxygen atom of CO(3)(2-) interacts with a water molecule in both lobes.
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Khan JA, Kumar P, Paramasivam M, Yadav RS, Sahani MS, Sharma S, Srinivasan A, Singh TP. Camel lactoferrin, a transferrin-cum-lactoferrin: crystal structure of camel apolactoferrin at 2.6 A resolution and structural basis of its dual role. J Mol Biol 2001; 309:751-61. [PMID: 11397094 DOI: 10.1006/jmbi.2001.4692] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Camel lactoferrin is the first protein from the transferrin superfamily that has been found to display the characteristic functions of iron binding and release of lactoferrin as well as transferrin simultaneously. It was remarkable to observe a wide pH demarcation in the release of iron from two lobes. It loses 50 % iron at pH 6.5 and the remaining 50 % iron is released only at pH values between 4.0 and 2.0. Furthermore, proteolytically generated N and C-lobes of camel lactoferrin showed that the C-lobe lost iron at pH 6.5, while the N-lobe lost it only at pH less than 4.0. In order to establish the structural basis of this striking observation, the purified camel apolactoferrin was crystallized. The crystals belong to monoclinic space group C2 with unit cell dimensions a=175.8 A, b=80.9 A, c=56.4 A, beta=92.4 degrees and Z=4. The structure has been determined by the molecular replacement method and refined to an R-factor of 0.198 (R-free=0.268) using all the data in the resolution range of 20.0-2.6 A. The overall structure of camel apolactoferrin folds into two lobes which contain four distinct domains. Both lobes adopt open conformations indicating wide distances between the iron binding residues in the native iron-free form of lactoferrin. The dispositions of various residues of the iron binding pocket of the N-lobe of camel apolactoferrin are similar to those of the N-lobe in human apolactoferrin, while the corresponding residues in the C-lobe show a striking similarity with those in the C-lobes of duck and hen apo-ovotransferrins. These observations indicate that the N-lobe of camel apolactoferrin is structurally very similar to the N-lobe of human apolactoferrin and the structure of the C-lobe of camel apolactoferrin matches closely with those of the hen and duck apo-ovotransferrins. These observations suggest that the iron binding and releasing behaviour of the N-lobe of camel lactoferrin is similar to that of the N-lobe of human lactoferrin, whereas that of the C-lobe resembles those of the C-lobes of duck and hen apo-ovotransferrins. Hence, it correlates with the observation of the N-lobe of camel lactoferrin losing iron at a low pH (4.0-2.0) as in other lactoferrins. On the other hand, the C-lobe of camel lactoferrin loses iron at higher pH (7.0-6.0) like transferrins suggesting its functional similarity to that of transferrins. Thus, camel lactoferrin can be termed as half lactoferrin and half transferrin.
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Khan JA, Griffiths D. Anomalous thermal expansion of dilute CuMn and AgMn alloys below 50K. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/8/5/009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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