Browsing by Author "M. Pandey"

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A 20-year-old woman with a painful swollen left thumb.
(2006) S.K. Tiwary; M.K. Singh; R.C. Shukla; M. Pandey; V.K. Shukla
[No abstract available]
A Bayesian estimation of reliability model using the linex loss function
(1994) M. Pandey; V.P. Singh; C.P.L. Srivastava
In this paper the problem of Bayes estimation of the reliability and the shape parameter p of a finite range failure time model is considered (assuming scale parameter θ is known). Following Zellner [A. Zellner, J. Am. Statist. Assoc. 81, 446-451 (1986)] the asymmetric loss function is used to obtain the Bayes estimators. Efficiencies of the proposed Bayes estimators are obtained with respect to the ordinary Bayes estimators and it was found that the proposed Bayes estimators are better than the ordinary Bayes estimators for quite a wide range of parameters. © 1994.
A hernia in the inguinal region is not always an inguinal hernia
(2007) Som Basu; M. Pandey; C.L.N. Sharma
A male patient of 60 years presented with a swelling in the left groin of 10 months duration. Past records showed bilateral lumbar sympathectomy and omentopexy done 20 and 6 years back, respectively, for Buerger's disease. Abdominal examination revealed a huge hernial swelling in the left groin extending from the symphysis pubis to anterior superior iliac spine measuring 25 × 18 cm. On exploration, the contents were intestines and omentum, which were coming out through a defect of 5 ×3 cm in the lower fibers of the conjoint muscle 4 cm cephalad to the deep ring, a finding which made the final diagnosis as an incisional hernia. We present this interesting case as a very rare complication of omentopexy, probably not reported previously, and an unusual case of an incisional hernia presenting as an inguinal hernia which is very difficult to diagnose unless encountered before. Its rarity and clinical challenge is highlighted. © Springer-Verlag 2007.
ABO and Rh blood groups in patients with cholelithiasis and carcinoma of the gall bladder
(1995) M. Pandey; A. Gautam; V.K. Shukla
[No abstract available]
An Unusual Presentation of Primary Chondrosarcoma of Bone
(Indian Medical Association, 1998) N.C. Aryya; M. Pandey; A. Gautam; V.K. Shukla
[No abstract available]
Approximate prediction limit for Weibull failure based on preliminary test estimator
(1986) M. Pandey; S.K. Upadhyay
In this paper we have considered type II censored sample from a two parameter Weibull distribution with the known scale parameter. Using the preliminary test estimator of the unknown shape parameter β proposed by Pandey (1983), the paper derives a method of finding the approximate prediction limit for the minimum or, more generally, the jthsmallest of a set of future observations from the Weibull or even extreme-value distribution. © 1986, Taylor & Francis Group, LLC. All rights reserved.
Bayes estimation of reliability in stress-strength model of Weibull distribution with equal scale parameters
(1986) M. Pandey; S.K. Upadhyay
The paper provides a Bayesian approach to inference about the reliability in a multicomponent stress-strength system. We consider Bayes' estimator of the system reliability from data consisting of a random sample from the stress distribution and one from the strength distribution when the two distributions are Weibull with equal and known scale parameters. The estimator of λ, ratio of two shape parameters, is also considered. The proposed estimators can be compared with the maximum likelihood estimators (mles). However, the comparison is carried out for single component stress-strength system and the Monte Carlo efficiencies are obtained. It is found that the proposed estimators are better than the corresponding mles. © 1986.
Bayes Estimator of Survival Probability from Randomly Censored Observations with Weibull Distribution of Time to Death
(1987) M. Pandey
This paper deals with Bayes estimation of survival probability when the data are randomly censored. Such a situation arises in case of a clinical trial which extends for a limited period T. A fixed number of patients (n) are observed whose times to death have identical Weibull distribution with parameters β and θ. The maximum times of observation for different patients are also independent uniform variables as the patients arrive randomly throughout the trial. For the joint prior distribution of (β, θ) as suggested by Sinha and Kale (1980, page 137) Bayes estimator of survival probability at time t (0
Bayes shrinkage estimation of reliability and the parameters of a finite range failure time model
(1993) M. Pandey; V.P. Singh
A finite range failure time distribution has been proposed and studied. For estimating the two parameters of this distribution, this paper considers a prior assumption that (1 - b) is the probability that the scale parameter θ and shape parameter p have the values θ0 and p0, respectively, and that the rest of the probability mass b(0 ≤ b ≤ 1) is distributed as h(p,θ) = h1(p)h2(θ). The value h1(p) is a uniform density for p and h2(θ) is an inverted gamma density for θ. With this prior density, Bayes estimators are first obtained and then Bayesian shrinkage estimators are defined. Bayesian shrinkage estimators are compared with maximum likelihood estimators (m.l.e.) and it was found that the proposed estimators are better than m.l.e. for quite a wide range of parameters. © 1993.
Bayes Shrinkage Estimators of Weibull parameters
(1985) M. Pandey; S.K. Upadhyay
Shrinking an unbiased estimator of a parameter towards a prior value of the parameter has been treated by Thompson, Lemmer, and others. The shrunken estimator is better than the unbiased estimator if true value of the parameter is close to its prior value and is less s-efficient otherwise. This paper considers whether it would be more realistic to postulate a prior distribution for the 2-parameters of the Weibull distribution around the prior values and use ordinary Bayes estimators instead of prior values in the shrunken estimator. Bayes shrinkage estimators have been obtained and their s-efficiencies were studied via Monte Carlo. The Bayes shrinkage estimators are better than the unbiased estimators. © 1985 IEEE
Bayesian inference in mixtures of two exponentials
(1988) M. Pandey; S.K. Upadhyay
This paper provides the Bayes estimators of scale parameters in two exponential distributions mixed in proportion p, which is assumed to be known. For deriving the Bayes estimators the prior distributions are chosen such that they are centered at the known prior values of the scale parameters. The Bayes estimators thus obtained are found to be equivalent to Thompson's shrinkage estimators. The Bayes estimator of reliability function and another estimator of reliability using the Bayes estimators of scale parameters are given. The efficiency of the proposed estimator of reliability with respect to its maximum likelihood estimator (mle) is studied by Monte Carlo simulation. Lastly, the Bayes confidence interval of reliability is obtained and its validity is examined by a Monte Carlo study of 500 samples. © 1988.
Bayesian shrinkage estimation of reliability from a censored sample from a finite range failure time model
(1989) M. Pandey; V.P. Singh
In this paper the problem of estimation of reliability function and scale parameter is considered from a type II censored sample from a finite range failure time distribution suggested by Ali and Islam. For estimating a parameter the shrunken estimator k + (1 - k) 0, where (0 ≤ k ≤ 1) is a 0205 0112 constant, was found to be better than its unbiased estimator if f is close to the natural origin f0. Following 0205 01 Lemmer and Pandey and Upadhyay we postulate a prior distribution for the scale parameter θ around the natural origin θ0 and use the Bayes estimator in place of f0 in the shrunken estimator. It is assumed that the shape parameter p is known. The Bayesian shrinkage estimator of the scale parameter and reliability function has thus been obtained. A comparison of the maximum likelihood estimator (m.l.e.), Bayes estimator and Bayes shrinkage estimator of each was undertaken and it was found that the proposed estimator is better than the m.l.e. and Bayes estimator. © 1989.
Bayesian shrinkage estimation of reliability in parallel system with exponential failure of the components
(1985) M. Pandey; S.K. Upadhyay
The paper presents a Bayesian shrinkage method of estimating the reliability of a parallel system with identical exponential distribution of failure times. Data is available from type II censored samples. Thompson (J. Am. Statist. Ass. 63, 113-123, 1968) proposed the ordinary shrunken estimator κ{script}θ + (1-κ{script})θ0, with κ{script} a constant (0 ≤ κ{script} ≤ 1) and θ0 the prior or guess value of θ, which is more efficient than the unbiased estimator θ if θ is close to θ0 and is less efficient otherwise. Here we postulate a prior distribution of θ around θ0 and use an ordinary Bayes estimator of θ instead of θ0 in the ordinary shrunken estimator. The Bayesian shrinkage estimator of parallel system reliability has thus been obtained and Monte Carlo study of its efficiency with respect to unbiased and maximum likelihood estimators (mles) was conducted. It was found that the proposed estimator is better. © 1985 Pergamon Press Ltd.
Bayesian shrinkage estimation of system reliability with Weibull distribution of components
(1987) M. Pandey; S.K. Upadhyay
This paper considers two different Bayesian shrinkage estimators of series system and parallel system reliabilities, based on type II censored samples, assuming that the lifetimes of the components follow independent Weibull distributions with known scale parameters. The mean squared errors and relative efficiencies of the estimators are investigated through Monte Carlo simulation studies. © 1987.
Biliary lipid peroxidation products in gallbladder cancer: Increased peroxidation or biliary stasis?
(2000) M. Pandey; V K Shukla; S. Singh; S K Roy; B R Rao
Gallbladder cancer is a common malignancy among women in India. The aetiology of gallbladder carcinoma is still obscure and although numerous factors have been implicated, none has stood the test of time. This study was carried out to evaluate the role of lipid peroxidation product 4-hydroxynonenal (HNE) in gallbladder carcinogenesis. High-performance liquid chromatography (HPLC) analysis was carried out in 30 bile samples obtained during laparotomy from patients with gallbladder cancer (n = 10), cholelithiasis (n = 10) and age- and sex-matched controls (n = 10). A significantly high concentration of HNE and lower concentration of biliary pH and electrolyte was observed in patients with carcinoma of the gallbladder compared with controls and patients with cholelithiasis. A significant correlation was also observed between biliary Na+ and K+ (r = 0.72), biliary Ca2+ and Na+ (r = 0.69) among controls. However, there was no correlation between HNE, electrolytes and pH among cancer patients. An increased concentration of biliary HNE and decreased concentration of electrolytes suggest biliary stasis rather then increased peroxidation in cancer patients. © 2000 Lippincott Williams & Wilkins.
Biological behavior and disease pattern of carcinoma gallbladder shown on 64-slice CT scanner: A hospital-based retrospective observational study and our experience
(2012) A.N.D. Dwivedi; M. Pandey; R.C. Shukla; V.K. Shukla; S. Gaharwar; B.N. Maurya
Purpose: The aim of this diagnostic observational study was to assess the spread and biological behavior of gallbladder cancer using 64-slice computerized tomography (CT) scanner in this particular geographic belt (eastern Uttar Pradesh, western Bihar, and northern Madhya Pradesh provinces of North India). Indians are ethnically and culturally different from their Western counterparts among whom the incidence of this disease is comparatively low. Subjects and Methods: After systemic examination, all patients (87) were subjected to ultrasonographic examination. All cases were histopathologically proven. Confirmed cases were subjected to volumetric CT examination of abdomen and pelvis, plain, post contrast and delayed phase. Results: Majority of the cases were adenocarcinoma. There was female preponderance with majority belonging to fifth and sixth decades. Commonest presentation was diffuse, irregular, enhancing wall thickening in 49.4%. Majority had invasion of liver parenchyma (74.7%). Cholelithiasis was seen in 48.3% cases. Invasion of biliary radicals was high (13.8-18.4%). Eleven cases had invasion of portal vein and tumor thrombus, with hepatic artery invasion in one case. In two cases, both hepatic artery and portal vein invasion was seen. Portal and peripancreatic nodal metastasis was seen in 58.5%. Distant metastasis was reported. Conclusion: Few studies involving the Indian population have attempted to use multi-row detector CT to define the biological behavior of carcinoma gallbladder. The opinion whether the pathology is operable or non-operable can reasonably be given. This large-scale, single-center study gives insight about the epidemiology and biological behavior of carcinoma gallbladder. Dwivedi AND 1 Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, BHU, Varanasi Pandey M 2 Department of Surgery, Institute of Medical Sciences, BHU, Varanasi Shukla R 3 Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, BHU, Varanasi Shukla V 4 Department of Surgery, Institute of Medical Sciences, BHU, Varanasi Gaharwar S 5 Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, BHU, Varanasi Maurya B 6 Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, BHU, Varanasi Shukla VK, Khandelwal C, Roy SK, Vaidya MP. Primary carcinoma of gall bladder: A review of a 16-year period at the university hospital. J Surg Oncol 1985;28:32-5. National Cancer registry Programme: Consolidated report of the population based cancer registries 1990-1996, Incidence and distribution of cancer, New Delhi: Indian Council of Medical Research, ICMR; 2001. p. 52-3. Kapoor VK, Mc Michael AJ. Gall Bladder Cancer: An ′Indian" disease. Natl Med J India 2003;16:209-13. Maram ES, Ludwig J, Kurland LT, Brian DD. Carcinoma of the gallbladder and extrahepatic biliary ducts in Rochester, Minnesota, 1935-1971. Am J Epidemiol 1979;109:152-75. Nervi F, Duarte I, Gomez G, Rodreguez G, Delpino G, Ferrerio O, et al. Frequency of the gallbladder cancer in Chile. Int J Cancer 1988;41:657. Soira M, Aro K, Pamilo M, Palvansalo M, Suramo I, Taavitsainen M. ultrasonography in carcinoma of gall bladder. Acta Radiol 1987;28:711-4. Palma LD, Rizzatto G, Pozzi-Mercerri RS, Bazzoccbi M. Gray scale ultrasonography in the evaluation of the carcinoma of the gall bladder. Br J Radiol 1980;53:662-7. Itai Y, Araki T, Yoshikawa K, Fureri S, Yashiro N, Tasaka A. Computed tomography of gall bladder carcinoma. Radiology 1980;137:713-8. Zatonski WA, La Vecchia C, Przewozniak K, maisonneuve P, Lowenfels AB, Boyle P. Risk factors for gall bladder cancer: A polish case control study. Int J Cancer 1992;51:707-11. Strom BL, Soloway RD, Rioz-Palenz JL, Rodriguez-Martinez HA, West SL, Kinman JL, et al. Risk factors for gallbladder cancer. Cancer 1995;76:1747-56. Zatonski WA, Lowenfels AB, Boyle P, Maisonneuve P, Bruno De Mesquita HB, Ghadirian P, et al. Epidemiologic aspects of gall bladder cancer. A case control study of the search programme of the International agency for Research on Cancer. J Natl Cancer Inst 1997;89:1132-8. Kats K, Akai S, Tominaga S, Kato I. A case control study of biliary tract cancer in Nigata Prefecture, Japan. Jpn J Cancer Res 1989;80:932-8. Waterhouse J, Muir C, Correa P, Powell J, editors. Cancer incidence in five continents, Vol 3, IARC Publication No. 15. Lyon: IARC; 1976. Zeman RK, Burrell Ml, editors. Gallbladder and Bile Duct Imaging: A clinical radiologic approach. New York: Churchill Livingstone; 1987. p. 292-307. Chaurasia P, Thakur MK, Shukla HS. What causes cancer gallbladder?: A review. HPB Surg 1999;11:217-24. Furlan A, Ferris JV, Hosseinzadeh K, Borhani AA. Gallbladder carcinoma update: Multimodality imaging evaluation, staging and treatment options. AJR Am J Roentgenol 2008;191:1440-7. Nakayama F. Recent progress in the diagnosis and gtreatment of carcinoma of gall bladder: Introduction. World J Surg 1991;15:313-4. Piehler JM, crichlow RW. Primary carcinoma of gall bladder. A collective review. Surg Gynecol Obstet 1978;147:929-42. Pandey M, Gautam A, Shukla VK. ABO and Rh blood groups in patients with cholelithiasis and carcinoma of the gall bladder. Br Med J 1995;310:1639. Shukla VK, Shukla PK, Pandey M, Rao BR, Roy SK. Lipid peroxidation products in bile from patients with carcinoma of the gall bladder. A preliminary study. J Surg Oncol 1994;54:258-62. Pandey M, Shukla PK, Gautam A, Rao BR, Roy SK, Shukla VK. Increased peroxidation of polyunsaturated fatty acids: A possible link in the peroxidant pathogenesis of carcinoma of the gallbladder with cholelithiasis. Proc. UICC XVI International Cancer Congress, Monduzzi Editore, Roma, Italy 1994; 3: 2055-8.. Shukla VK, Tiwari SC, Roy SK. Biliary bile acids in cholelithiasis and carcinoma of the gall bladder. Eur J Cancer Prev 1993;2:155-60. Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc 1958;53:457-81. Silk YN, Dougras HO Jr, Nava HR, Driscoll DL, Tartarian G. Carcinoma of the gall bladder. The Rosewerr Park experience. Ann Surg 1989;210:751-7. Pandey M, Pathak AK, Gautam A, Aryya NC, Shukla VK. Digestive diseases and sciences. Dig Dis Sci 2001;46:1145-51. Yoshimitsu K, Honda H, Shinozaki K, Aibe H, Kuroiwa T, Irie H, et al. Helical CT of the local spread of carcinoma of the gall bladder: Evaluation of the gall bladder: Evaluation according to the TNM system in patients who underwent surgical resection. AJR Am J Roentgenol 2002;179:423-8. Grand D, Horton MK, Fishman EK. CT of the gall bladder: Spectrum of disease. AJR Am J Roentgenol 2004;183:163-70. Rckert JC, Rckert RI, Gellert K, Hecker K, Mller JM. Surgery for carcinoma of the gallbladder. Hepatogastroenterology 1996;43:527. Fong Y, Wagman L, Gonen M, Crawford J, Reed W, Swanson R, et al. Evidence-based gallbladder cancer staging: Changing cancer staging by analysis of data from the National Cancer Database. Ann Surg 2006;243:767. Kiran RP, Pokala N, Dudrick SJ. Incidence pattern and survival for gallbladder cancer over three decades-an analysis of 10301 patients. Ann Surg Oncol 2007;14:827. Kapoor VK, Pradeep R, Haribhakti SP, Sikora SS, Kaushik SP. Early carcinoma a of gall bladder: An elusive disease. J Surg Oncol 1996;62:284-7.
Carcinoma of the ovary masqurading as gall bladder neoplasm.
(1997) V.K. Shukla; N.C. Arya; M. Pandey; A. Gautam
[No abstract available]
Diet and gallbladder cancer: A case-control study
(2002) M. Pandey; V.K. Shukla
Cancer of the gallbladder is rare but fatal, and has an unusual geographic and demographic distribution. Gallstones and obesity have been suggested as possible risk factors. As diet is known to influence both these factors, we carried out the present study to evaluate the possible role of diet in gallbladder carcinogenesis. A case-control study involving 64 newly diagnosed cases of gallbladder cancer and 101 cases of gallstones was carried out. The dietary evaluation was carried out by the dietary recall method based on a preset questionnaire developed specifically for the present study, keeping in mind the common dietary habits prevailing in this part of the world. Odds ratios (OR) and 95% confidence interval (CI) were calculated for various dietary items. A significant reduction in odds ratio was seen with the consumption of radish (OR 0.4; 95% CI 0.17-0.94), green chilli (OR 0.45; 95% CI 0.21-0.94) and sweet potato (OR 0.33; 95% CI 0.13-0.83) among vegetables, and mango (OR 0.4; 95% CI 0.16-0.99), orange (OR; 0.45; 95% CI 0.22-0.93), melon (OR 0.3; 95% CI 0.14-0.64) and papaya (OR 0.44; 95% 0.2-0.64) among fruits. A reduction in odds was also seen with the consumption of cruciferous vegetables, beans, onion and turnip, however the difference was not statistically significant. On the other hand, an increase in the odds was observed with consumption of Capsicum (OR 2.2), beef (OR 2.58), tea (OR 1.98), red chilli (OR 1.29) and mutton (OR 1.2), however the difference was statistically not significant. In conclusion, the results of the present study show a protective effect of vegetables and fruits on gallbladder carcinogenesis, but red meat (beef and mutton) was found to be associated with increased risk of gallbladder cancer. © 2002 Lippincott Williams & Wilkins.
Discovery of fossil micrometeorites from the Deccan trap intertrappeans
(University of Arkansa, 2024) V.P. Singh; N.G. Rudraswami; Nittala V. Chalapathi Rao; Matthew J. Genge; M. Pandey; S. Sreekuttan; S. Chattopadhaya
The Cretaceous–Paleogene (K-Pg) boundary represents the extinction of ~70% of species, a prominent Chicxulub impact event and Deccan volcanism. This work reports the first attempt to extract the micrometeorites (MMs) from the Deccan intertrappean horizons. Eighty-one spherical particles were studied for their morphological, textural, and chemical characteristics. Intact cosmic spherules with ferromagnesian silicates (6) and Fe-Ni oxide (7) compositions correspond to MMs from the deep sea and Antarctica. Silicate and Fe-Ni spherules in this study showcase remarkable preservation, a testament to the highly favorable conditions present. Fe spherules (38) with iron oxide compositions exhibit diagenetic alteration during preservation. Textural analysis of 30 Fe spherules reveals a dendritic, interlocking pattern and slightly elevated Mn content, suggesting these may be fossilized I-type MMs. However, eight Fe spherules with blocky and cubical granular textures resemble oxidized pyrite spherules. Al-Fe-Si spherules (30) possess a significant enrichment of Al and Si within their Fe-oxide-dominated composition. Group-I Al-Fe-Si spherules (15) display zoned Al-Fe-Si oxide composition, dendritic Mg-Cr spinel grains, and aerodynamic features, all indicative of impact spherules. The finding of these impact spherules from sampled Deccan intertrappean layer raises the possibility that these paleosols were deposited during the Chicxulub impact event, the only identified impact event with global distribution during the Deccan volcanism time frame. This unique location provides an opportunity for the simultaneous collection of well-preserved MMs, impact, and volcanic spherules. The exceptional preservation of the studied MMs is likely due to a combination of non-marine environments, atypical climatic conditions, and rapid deposition. This study further investigates the potential role of cosmic dust flux in the K-Pg extinction event. We propose that the enhanced cosmic dust flux, a likely scenario during the K-Pg boundary period, synergistically mixing with impact dust in the upper atmosphere, may have intensified and extended the harsh climatic conditions at the K-Pg boundary. Subsequently, the deposition of this dust, enriched in bioavailable iron, on Earth's surface might have contributed to the swift recovery of life and environmental conditions. © 2024 The Meteoritical Society.
Easy and cost-efficient method for tumour localization in patients with breast cancer undergoing neoadjuvant chemotherapy followed by breast conservation therapy
(Oxford University Press, 2021) D. Biswas; S.V. Chigurupati; M. Pandey
[No abstract available]