Yashwant Kumar - Academia.edu (original) (raw)

Papers by Yashwant Kumar

Journal of Biomolecular Structure and Dynamics, 2020

Drug repurposing is an apt choice to combat the currently prevailing global threat of COVID-19, c... more Drug repurposing is an apt choice to combat the currently prevailing global threat of COVID-19, caused by SARS-Cov2in absence of any specific medication/vaccine. The present work employs state of art computational methods like homology modelling, molecular docking and molecular dynamics simulations to evaluate the potential of two widely used surfactant drugs namely chenodeoxycholate(CDC) and ursodeoxycholate (UDC), to bind to the envelope protein of SARS-Cov2(SARS-Cov2-E).The monomeric unit of SARS-Cov2-E was modelled from a close homologue (>90% sequence identity) and a pentameric assembly was modelled using symmetric docking, followed by energy minimization in a DPPC membrane environment. The minimized structure was used to generate best scoring SARS-Cov2-E-CDC/UDC complexes through blind docking. These complexes were subjected to 230 ns molecular dynamics simulations in triplicates in a DPPC membrane environment. Comparative analyses of structural properties and molecular interaction profiles from the MD trajectories revealed that, both CDC and UDC could stably bind to SARS-Cov2-E through H-bonds, water-bridges and hydrophobic contacts with the transmembranechannelresidues.T30 was observed to be a key residue for CDC/UDC binding. CDC/UDC binding affected the H-bonding pattern between adjacent monomeric chains, slackening the compact transmembrane region of SARS-Cov2-E. Additionally, the polar functional groups of CDC/UDC facilitated entry of a large number of water molecules into the channel. These observations suggest CDC/UDC as potential candidates to hinder the survival of SARS-Cov2 by disrupting the structure of SARS-Cov2-E and facilitating the entry of solvents/polar inhibitors inside the viral cell.

Expert review of clinical immunology, Jan 16, 2016

Diagnostic pathology, Jan 8, 2007

Papillary glioneuronal tumor (PGNT) is a recently described lesion of the brain, which is still n... more Papillary glioneuronal tumor (PGNT) is a recently described lesion of the brain, which is still not included as a separate entity in WHO classification. To date 32 cases of PGNT have been reported in the world literature. We report the 33rd case, a 41-year-old male who presented with pain in the nape of the neck. MRI showed a large, predominantly solid mass involving the cerebral parenchyma of the left temporal and parieto-occipital lobes with extension across the midline. Histologically, it was a mixture of glial and neuronal components. Architecturally, the tumor was notable for its pseudopapillary pattern with hyalinized vessels. PGNT is considered as a low grade neoplasm and surgical excision has been curative in most of the cases. More cases of PGNT need to be reported as they may add further knowledge about its biologic behavior and allow its recognition and classification.

Bioactive Dietary Factors and Plant Extracts in Dermatology, 2012

Diagnostic Pathology, 2009

It has been more than 50 years since antinuclear antibodies were first discovered and found to be... more It has been more than 50 years since antinuclear antibodies were first discovered and found to be associated with connective tissue diseases. Since then different methods have been described and used for their detection or confirmation. For many decades immunofluorescent antinuclear antibody test has been the "gold standard" in the diagnosis of these disorders. However to increase the sensitivity and specificity of antinuclear antibody detection further approaches were explored. Today a battery of newer techniques are available some of which are now considered better and are competing with the older methods. This article provides an overview on advancement in antinuclear antibody detection methods, their future prospects, advantages, disadvantages and guidelines for use of these tests.

Journal of Clinical Pathology, 2006

Japanese Journal of Clinical Oncology, 2009

Desmoplastic reaction of the stroma is a part and parcel of several malignancies. It may be seen ... more Desmoplastic reaction of the stroma is a part and parcel of several malignancies. It may be seen within or at a site distant from the main tumour. Irrespective of the site of fibrosis in tumours, it portends a poor prognosis as it is generally associated with invasion and metastasis. In this report, we present a unique case of a 78-year-old male patient with clear cell renal carcinoma (CCRC) who presented with a lump in the right loin. On magnetic resonance imaging scan, the mass was arising from the middle part of the right kidney. The nephrectomy was done and specimen on examination revealed a variegated tumour with another whitish solid mass in the surrounding perirenal fat. The kidney tumour showed features of CCRC, whereas whitish mass was entirely composed of proliferating spindle cells. Therefore, the mass mimicked a second tumour not only on gross but even on microscopy. The special stains (Elastic-van Gieson, Masson-Trichrome, Periodic acid schiff's, alcian blue and mucicarmine), immunostaining (cytokeratin, vimentin, epithelial membrane antigen, smooth muscle actin, S-100, HMB-45, CD34 and CD117) patterns and ultrastructural features all, however, favoured it to be an extensive peritumoural fibrotic reaction rather than a neoplasm. The observation provokes important questions like whether the reaction in the index case is an example of tumour-induced fibrosis or is an unassociated phenomenon and, in the case of former, what are factors that govern the extent and site of fibrosis, i.e. intratumoural, peritumoural or away from the tumour. The finding may also help in further research and understanding of the role of stroma in cancer progression and developing stromal antigen-targeted therapies in CCRC.

Expert Review of Clinical Immunology, 2013

Diagnostic pathology, Jan 22, 2006

The Dabska tumor also known as Endovascular papillary angioendothelioma is a rare type of hemangi... more The Dabska tumor also known as Endovascular papillary angioendothelioma is a rare type of hemangioendothelioma characterized by intraluminal papillary endothelial structures. Most of these are superficial in location but occurrence in deeper tissues is also known. We describe case report of testicular Dabska tumor in a child presenting as inguinal hernia. To the best of our knowledge this is the first case report describing the occurrence of this rare entity in testis.

JRSM short reports, Jan 9, 2010

JRSM Short Reports, 2011

Background The aim was to evaluate and correlate anxiety and depression levels with response to n... more Background The aim was to evaluate and correlate anxiety and depression levels with response to neoadjuvant chemotherapy in patients with breast cancer. The study also assessed the effects of family support on distress levels. Design It was a prospective study in a cohort of 84 patients with locally advanced breast cancer. These assessments were done using the Hospital Anxiety and Depression Scale (HADS). Setting A prospective study in a developing world setting. Participants Eighty-four patients with locally advanced breast cancer receiving neoadjuvant chemotherapy were included after taking an informed consent and ethical committee clearance. Main outcome measures A significant correlation was observed between response to neoadjuvant chemotherapy and depression levels in breast cancer patients. Joint family and literacy levels also had an impact on the levels of depression observed. Results A total of 84 patients receiving neoadjuvant chemotherapy for breast cancer were evaluated ...

Urologia Internationalis, 2007

Background: Emphysematous renal tract disease (ERTD) is a rare necrotizing infection of the renal... more Background: Emphysematous renal tract disease (ERTD) is a rare necrotizing infection of the renal parenchyma and urinary tract caused by gas-producing organisms. ERTD deserves special attention because of its life-threatening potential. Objectives: To study the clinical features, radiological classification and prognostic factors of ERTD; and to compare the modalities of management and the outcome among the various radiological classes of ERTD. Patients and Methods: Twenty consecutive patients with diabetes and ERTD, seen over last 3 years in a tertiary care institute of north India, were included in the study. All patients were subjected to computerized tomography (CT) after initial diagnosis by ultrasonography. They were classified into 5 classes as previously described. All patients included in the study were conservatively managed with appropriate antibiotics and/or percutaneous drainage or surgery if required. Result: Mean age (± SD) of these subjects was 54.4 ± 20.6 years; dur...

Pituitary, 2006

Pituitary abscess is a rare disorder and its presenting manfestations are non-specific therefore,... more Pituitary abscess is a rare disorder and its presenting manfestations are non-specific therefore, the diagnosis is usually made either postoperatively or at postmortem. We describe four such cases seen over a period of 10 years. All the patients presented with fever, systemic signs of toxaemia and endocrine dysfunctions. Two of them had pre-existing pituitary pathology. A preoperative diagnosis of pituitary abscess was considered in all in view of characteristic MR findings. Three patients underwent transsphenoidal drainage of abscess, whereas the remaining one succumbed to sepsis and was diagnosed at necropsy. Offending organisms including Pseudomonas, Acinetobacter and Staphylococcus were

Diagnostic pathology, Jan 14, 2006

Duodenal metastasis is rare in renal cell carcinoma (RCC) and early detection, especially in case... more Duodenal metastasis is rare in renal cell carcinoma (RCC) and early detection, especially in case of a solitary mass, helps in planning further therapy. We present the case report of a 55 year old male with duodenal metastasis of RCC. This patient presented with jaundice and abdominal lump one year after nephrectomy. On upper gastrointestinal endoscopy a submucosal mass lesion was noted in the duodenum, the biopsy of which revealed metastasis. In a nephrectomized patient presenting with jaundice and an abdominal mass, the possibility of metastasis should be suspected and a complete evaluation, especially endoscopic examination followed by biopsy, should be carried out.

Polyphenols in Human Health and Disease, 2014

Polyphenols are natural, organic chemicals characterized by the presence of multiple phenol struc... more Polyphenols are natural, organic chemicals characterized by the presence of multiple phenol structural units. They are abundant in plant products and contribute to the beneficial health effects of a vegetarian diet. Many scientific studies support the role of polyphenols in the prevention of several conditions like cardiovascular and neurodegenerative diseases, diabetes, osteoporosis, and even cancer. In recent years the concept that dietary polyphenols are protective agents against the risk of cancers has gained considerable attention. Polyphenols are strong antioxidants and are reported to have anti-inflammatory effects, balance the cell cycle, apoptosis, and various molecular pathways that are dysregulated in cancers. All of these effects have been studied in various body tumors; however, data on skin cancers is meager. The aim of this chapter is to discuss the dietary polyphenols in a concise manner, their sources, mechanisms of carcinogenesis, and their protective effects in relation to the skin cancers.

Clinics and Practice, 2011

We report a case of extremely rare variant of ano-rectum malignant tumor. The tumor is often misd... more We report a case of extremely rare variant of ano-rectum malignant tumor. The tumor is often misdiagnosed as either hemorrhoids or rectal polyp, which are benign diseases. On histology also this variant may be confused with other more commonly occurring spindle cell lesions in this area; its recognition is therefore important as it normally has a poor prognosis.

Journal of Medical Case Reports, 2010

Introduction: The ovary is a common site of metastasis from various organs. However, little is kn... more Introduction: The ovary is a common site of metastasis from various organs. However, little is known about gallbladder carcinoma metastasizing to the ovaries and presenting as a primary ovarian tumor. Case presentation: We report two cases of a metastatic gallbladder carcinoma which mimicked a primary ovarian tumor in a 35-year-old and a 62-year-old North Indian woman. Clinically, both our patients presented with abdominal masses without obvious signs and symptoms related to gallbladder carcinoma. Radiology suggested the possibility of a primary ovarian tumor with chronic cholecystitis and cholelithiasis. The gross features also mimicked a primary malignant ovarian tumor in the first case and a benign mucinous neoplasm in the second case. Exact diagnoses could only be made after thorough sampling from both the ovaries and gallbladder. Conclusions: Gallbladder carcinoma with metastasis to the ovaries can mimic both malignant and benign primary ovarian tumors. Extensive cystic change in the ovary due to metastasis from gallbladder carcinoma has rarely been reported. A high index of suspicion and thorough sampling are essential to avoid misdiagnosis in such cases.

Journal of Medical Case Reports, 2008

Introduction: Involution of lactation is a physiological process. Rarely, it may be delayed and t... more Introduction: Involution of lactation is a physiological process. Rarely, it may be delayed and troublesome for the lactating woman. Though lactation-induced changes in breast are well known, morphological features of delayed involution are not clear. Case presentation: We report a case of a 22-year-old lactating mother who presented with a painful, non-resolving breast mass 5 months after delivery. Clinically, it simulated an inflammatory carcinoma. Histopathology, however, revealed involuting lactational changes. Conclusion: To the best of our knowledge, lactational involution with such a presentation has not been described in the English literature. The case needs to be reported so that this entity can be considered among the differential diagnoses of breast masses in a lactating patient.

International Journal of Surgical Pathology, 2008

Invasive papillary breast carcinoma is a subtype of breast cancer that is more frequent in males.... more Invasive papillary breast carcinoma is a subtype of breast cancer that is more frequent in males. An intraductal carcinoma can coexist with it but association of an infiltrating carcinoma has not been described. This report presents a rare case of a 35-year-old man with dual malignancy in the same breast. The patient had two separate nodules, one with the morphology of invasive papillary carcinoma and the other having features of an infiltrating ductal carcinoma. To the best of our knowledge this is the first case report describing the coexistence of these two entities.