Biplab Pal

Effect of the refractive index dip on the propagation characteristics of step index and graded index fibers

Abstract In this paper we have used the perturbation technique to study the effect of a gaussian dip in the dielectric constant profile on the propagation characteristics of step index and graded index fibers. Explicit expressions for the propagation constants have been obtained for both cases. It has been shown that the refractive index dip has a considerable effect on the dispersion characteristics of the fiber.

Predicting Dispersion Minimum in a Step Index Monomode Fiber: a Comparison of the Theoretical Approaches

An accurate calculation of the total dispersion coefficient for a step-index monomode fiber is made and therefrom a comparison of the frequently used approximate approaches for the prediction of dispersion minimum in step-index monomode fibers is made. It is shown that the two approximate approaches due to Gloge [4] and South [10] may lead to significant errors in the prediction of (i) the wavelength X0 of dispersion minimum and ( ) core diameter required to attain zero total dispersion at a specified wavelength. For typical fiber parameters Gloges approximation may lead to prediction of λο which is as much as 10% higher than that predicted by our accurate calculation.

To evaluate efficacy and safety of amphotericin B in two different doses in the treatment of post kala-azar dermal leishmaniasis (PKDL)

Background Post kala-azar dermal leishmaniasis (PKDL) is a skin disorder that usually occurs among patients with a past history of visceral leishmaniasis (VL). Cases are also reported without a history of VL. There is no satisfactory treatment regimen available at present. We aimed to compare the efficacy and safety of amphotericin B in two different doses (0.5mg/kg vs 1mg/kg) in a prospective randomized trial in 50 PKDL patients. Methods In this open label study 50 patients with PKDL, aged between 5–60 years were randomized in two groups. Group A received amphotericin B in the dose of 0.5 mg/kg in 5% dextrose, daily for 20 infusions for 3 courses at an interval of 15 days between each course and Group B received amphotericin B in the dose of 1mg/kg in 5% dextrose on alternate days, 20 infusions for 3 courses an interval of 15 days between each course and followed up for one year. Results A total of 50 patients were enrolled, 25 in each of group A and group B. Two patients lost to follow up and three patients withdrew consent due to adverse events. The initial cure rate was 92% in group A and 88% in group B by intention to treat analysis and final cure rate by per protocol analysis was 95.65% and 95.45% in group A and group B respectively. Two patients each from either group relapsed. Nephrotoxicity was the most common adverse event occurring in both the groups. Conclusion The lower dose appears to have fewer adverse events however, nephrotoxicity remains a problem in both regimens. The 0.5mg/kg regimen may be considered instead of the higher dosage however safer treatments remain critical for PKDL treatment.

Knowledge, stigma, health seeking behaviour and its determinants among patients with post kalaazar dermal leishmaniasis, Bihar, India

Background Lesishmaniasis is a neglected tropical disease endemic in Bihar, India. Inappropriate health seeking behaviour of post kala-azar dermal leishmaniasis (PKDL) patients may increase the disease duration, severity and transmissibility. Simultaneously, lack of knowledge and perceived stigma may also increase the length of delay in receiving treatment. This ultimately effects the kala-azar elimination program. Methods A cross sectional study was conducted in 120 confirmed PKDL patients, aged 18 years and older. Data related to knowledge and health seeking behaviour was collected by a pre-tested questionnaire. EMIC stigma scale was used for assessing the perceived stigma. Patients were personally interviewed after taking informed consent. Data analysis was done by using SPSS 16 software. Results The time between appearance of symptoms and first medical consultation (patient delay) ranged from 15 days to 5475 days (15 years) with a median of 285 days. The time between first medical consultations to onset of specific treatment (system delay) ranged from 2 to 5475 days with a median of 365 days. Many patients approached first to quacks (8.4%), homeopathic and ayurvedic practitioners (25.8%) upon recognition of symptoms. Majority of the patients (68.3%) had poor knowledge about PKDL and its vector. Type of skin lesions and gender had significant association with patient delay and system delay respectively (p<0.05). Distance to primary health centre (PHC) had significant association with patients delay as well as system delay (p<0.05). Patients with younger age, unmarried and polymorphic lesions had higher stigma (p<0.05). Patients with PKDL feel stigmatized in different areas. Conclusion PKDL treatment delays were unacceptably high and patients had poor knowledge compounded with feelings of stigmatization. To reduce the delay, a system may be evolved to establish some sort of public-private collaboration, besides awareness programs should be tailored, and implemented for improving the patient education regarding the disease and its linkage with VL.

A relapse case of HIV-PKDL co-infection associated with diabetes and its microvascular complications

A relapse case of HIV-PKDL co-infection associated with diabetes and its microvascular complications Rakesh Kumar, Vidyanand Rabidas, Biplab Pal, Roshan Kamal Topno, Kanhaiya Agarwal, Rajendra Babu, Chandra Shekhar Lal, Neena Verma, Pradeep Das, Krishna Pandey Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna, Bihar, India Department of Pharmacy Practice, National Institute of Pharmaceutical Education and Research, Hajipur, Bihar, India Department of Epidemiology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna, Bihar, India Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna, Bihar, India Department of Pathology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna, Bihar, India Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna, Bihar, India Asian Pac J Trop Dis 2017; 7(3): 183-184

Efficacy and Safety of Liposomal Amphotericin B for Visceral Leishmaniasis in Children and Adolescents at a Tertiary Care Center in Bihar, India

Liposomal amphotericin B is being used increasingly to reduce the burden of kala-azar from the Indian subcontinent. There are studies which have evaluated efficacy and safety of liposomal amphotericin B for visceral leishmaniasis in all age groups. However, the only study that specifically addressed treatment of childhood visceral leishmaniasis did not include all ages or document renal and liver function. We, therefore, felt it was important to reassess the efficacy and safety of single dose liposomal amphotericin B in children and adolescents. A total of 100 parasitologically confirmed visceral leishmaniasis patients aged < 15 years were included in this study. Participants consisted of 65 males and 35 females. All of them had come from the endemic region of Bihar. They were administered one dose intravenous infusion of liposomal amphptericin B at 10 mg/kg body weight. Efficacy was assessed as initial and final cure at 1 and 6 months, respectively, and safety of all participants who were recruited in the study. The initial and final cure rate by per protocol analysis was 100% and 97.9%, respectively. Chills and rigors were the most commonly occurring adverse events (AEs). All the AEs were mild in intensity, and none of the patients experienced any serious AEs. No patients developed nephrotoxicity. Our finding indicates that liposomal amphotericin B at 10 mg/kg body weight is safe and effective in children. Results of our study support the use of single dose liposomal amphotericin B in all age group populations for elimination of kala-azar from the Indian subcontinent.

Para-kala-azar dermal Leishmaniasis cases in Indian subcontinent – A case series

1Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Patna, India, 2Department of Epidemiology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Patna, India, 3Department of Pharmacy Practice, National Institute of Pharmaceutical Education and Research, Hajipur, India, 4Department of Clinical Biochemistry, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Patna, India, 5Department of Pathology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Patna, India, 6Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Patna, India

An Early Sign of Wilson’s Disease: Dysarthria

Dear Editor, We would like to present here, a case of Wilson’s disease (WD), who was having a history of dysarthria since 3 months. A 10-year-old male child was admitted to Neurology Department of a tertiary care hospital in northeast India. As per the medical history of patient which was narrated by his mother, patient had been having episodes of high grade fever, loose motions and difficulty in speaking, for around 3 months. After consulting a private practitioner, fever and loose motions of the patient subsided, but slurred speech was persistent. Gradually, patient developed a low pitched voice, was unable to hold his footwear because of abnormal posturing of left leg toe and he had difficulty in chewing and swallowing. On examination, his vital signs were normal, except icterus and pallor. Ceruloplasmin is a serum glycoprotein which carries majority of copper in the blood and the patients with WD have low levels of ceruloplasmin [1]. In contrast, in our case, serum ceruloplasmin was within normal range, i.e. 324mg/l (normal 200-350mg/l), whereas serum copper was 46μg/dl (normal 70-140μg/dl). The haemoglobin concentration was 16gm%, white blood cell count was 9.1×103/mm3 and platelet count was 106×103/mm3. The serum concentrations of electrolytes were normal, creatinine was 0.36mg% and total bilirubin was 0.3mg% (direct fraction 0.2mg). Serum levels of AST, ALT and alkaline phosphatase were 88, 65 and 242U/L respectively. The 24 hour urine copper level was 835.48μg/day (normal 32-64μg/day). The diagnosis was made on the basis of urine copper levels, Kayser-Fleischer ring and face of giant panda on T2-weighted images seen on Magnetic Resonance Imaging. The penicillamine test was not performed in this case. At the hospital, tablet distamine (penicillamine 250mg) and tablet zincolac (folic acid 1.5mg, pyridoxine 3mg, riboflavin 10mg, thiamine 10mg, calcium pantithenate 5mg, lacto bacillus sporegens -60 million spores, niacinamide 45mg and zince sulphate 45mg) were prescribed to the patient and he was then discharged after one week. Thus, we can depict that tablet distamine was prescribed as a chelator to form penicillamine-copper complexes, while tablet zincolac was prescribed to block copper absorption from the intestinal track. However, after a few days, patient was again admitted with the complaint of aggravated abnormal behaviour and dystonia which involved tongue, right upper limb, left lower limb and right foot. The clinical features indicated potential intolerance to penicillamine and physician advised the patient’s mother to withdraw the tablet distamine. Tablet trientine dihydrochloride (triethylenetetramine 1000mg) was prescribed instead. In WD, copper accumulates in gray and white matter along with the basal ganglia, resulting in improper modulation of the basal ganglia by the subthalamic nucleus [2]. The mixed dysarthria with hypotonia and dystonia is common, because copper damages the extrapyramidal pathways as well as various components of motor system [3]. Initially, patient had difficulty in pronouncing lingual and he gradually developed a slower speech rate, hypophonia, variation in loudness, abnormal stress patterns on words, stuttering and palilalia. Thus, dysarthria in patients can be considered as an effective monitor of progress in the treatment of this disease [4]. This case indicated that dysarthria should not be overlooked in patients and that its cause should be figured out, for early detection of disease and to begin appropriate treatment.