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Biomedical subjects

Sanjay Kumar

Publications and source records attributed to Sanjay Kumar.

At least 91 records · Page 5Linked to original sources
PubMed2003

Innate immunity mediated by the cytokine IL-1 homologue 4 (IL-1H4/IL-1F7) induces IL-12-dependent adaptive and profound antitumor immunity.

Recently, several novel members of the IL-1 family have been identified. The possible therapeutic utility and the underlying biologic role of these new members remain unclear. In the present study we analyzed the anti-tumor activity of human IL-1 homologue 4(IL-1H4; renamed IL-F7) by adenovirus-mediated gene transfer (AdIL-1H4) directly into murine tumors. In vitro expression analysis showed that IL-1H4 was a secretory protein. Treatment of an established MCA205 mouse fibrosarcoma by single intratumoral injection of AdIL-1H4 resulted in significant growth suppression. Furthermore, complete inhibition of tumor growth was observed following multiple injections of AdIL-1H4. The anti-tumor activity of IL-1H4 was abrogated in nude and SCID mice and in IL-12-, IFN-gamma-, or Fas ligand-deficient mice. In contrast, IL-1H4 was able to confer substantial anti-tumor effects in NKT-deficient mice. These results suggest that IL-1H4 could play an important role in the link between innate and adaptive immunity and may be useful for tumor immunotherapy.

Adenoviridae↗
PubMed2003

Proteoglycan degradation after injurious compression of bovine and human articular cartilage in vitro: interaction with exogenous cytokines.

OBJECTIVE: Traumatic joint injury leads to an increased risk of osteoarthritis (OA), but the progression to OA is not well understood. We undertook this study to measure aspects of proteoglycan (PG) degradation after in vitro injurious mechanical compression, including up-regulation of enzymatic degradative expression and cytokine-stimulated degradation. METHODS: Articular cartilage tissue explants were obtained from newborn bovine femoropatellar groove and from adult normal human donor knee and ankle tissue. Following injurious compression of the cartilage, matrix metalloproteinase 3 (MMP-3) and MMP-13 messenger RNA (mRNA) expression levels were measured by Northern analysis, and PG loss to the medium after cartilage injury was measured in the presence and absence of added exogenous cytokine (interleukin-1alpha [IL-1alpha] or tumor necrosis factor alpha [TNFalpha]). RESULTS: During the first 24 hours after injury in bovine cartilage, MMP-3 mRNA levels increased 10-fold over the levels in control cartilage (n = 3 experiments), whereas MMP-13 mRNA levels were unchanged. PG loss was significantly increased after injury, but only by 2% of the total PG content and only for the first 3 days following injury. However, compared with injury alone or cytokine treatment alone, treatment of injured tissue with either 1 ng/ml IL-1alpha or 100 ng/ml TNFalpha caused marked increases in PG loss (35% and 54%, respectively, of the total cartilage PG content). These interactions between cytokine treatment and injury were statistically significant. In human knee cartilage, the interaction was also significant for both IL-1alpha and TNFalpha, although the magnitude of increase in PG loss was lower than that in bovine cartilage. In contrast, in human ankle cartilage, there was no significant interaction between injury and IL-1alpha. CONCLUSION: The cytokines IL-1alpha and TNFalpha can cause a synergistic loss of PG from mechanically injured bovine and human cartilage. By attempting to incorporate interactions with other joint tissues that may be sources of cytokines, in vitro models of mechanical cartilage injury may explain aspects of the interactions between mechanical forces and degradative pathways which lead to OA progression.

Adult↗
PubMed2003

Effects of brief ischemia and reperfusion on the myocardium and the role of nitric oxide.

Brief myocardial ischemia/reperfusion has complex effects on the myocardium. In the short term the myocardium may be stunned with temporarily reduced contractile function, though this may also be accompanied by the modification and de novo synthesis of proteins that protect the heart against subsequent early or delayed insults. Repeated episodes of non-lethal ischemia, which are common in the clinical setting, combine all of these phenomena and may ultimately result in chronic contractile dysfunction. Nitric oxide is intimately linked to many of these alterations in cellular function and defense. This article examines data predominantly from in vivo large animal studies that relate to these ischemia-induced changes, the evidence for the proposed mechanisms behind both myocardial stunning and preconditioning while concentrating on the role of nitric oxide in these conditions.

Animals↗
PubMed2003

p38 MAP kinases: key signalling molecules as therapeutic targets for inflammatory diseases.

The p38 MAP kinases are a family of serine/threonine protein kinases that play important roles in cellular responses to external stress signals. Since their identification about 10 years ago, much has been learned of the activation and regulation of the p38 MAP kinase pathways. Inhibitors of two members of the p38 family have been shown to have anti-inflammatory effects in preclinical disease models, primarily through the inhibition of the expression of inflammatory mediators. Several promising compounds have also progressed to clinical trials. In this review, we provide an overview of the role of p38 MAP kinases in stress-activated pathways and the progress towards clinical development of p38 MAP kinase inhibitors in the treatment of inflammatory diseases.

Animals↗
PubMed2003

Neural network approach to classify infective keratitis.

PURPOSE: Infective keratitis is a major sight-threatening condition in developing countries like India. An early diagnosis of infective keratitis is critical to its treatment. Epidemiological trends, morphological features of corneal ulceration and presence of other risk factors often dictate choice of initial treatment. This work assesses the usefulness of classification of infective keratitis by artificial neural network (ANN). METHODS: Forty input variables from each of the sixty-three known bacterial or fungal ulcers provided the basis for training a three layer feed-forward neural network. The trained neural network classified another set of forty-three corneal ulcers. RESULTS: Trained artificial neural network could classify correctly all sixty-three cornea ulcers in the training set. In the test set, the artificial neural network correctly classified 39 out of 43 cornea ulcers. Specificity for bacterial and fungal categories was 76.47% and 100% respectively. Accuracy of classification by neural network was 90.7% and compared significantly better than clinicians' prediction of 62.8% (p < 0.01). CONCLUSION: ANN has the potential to help clinicians classify corneal ulcers more accurately.

Corneal Ulcer↗
PubMed2003

Placement of half-pins for supra-acetabular external fixation: an anatomic study.

An alternative location for placement of half-pins during pelvic external fixation is the dense supra-acetabular bone in the region of the anterior-inferior iliac spine. Although these fixators have gained popularity, to the authors' knowledge there are no studies evaluating the potential anatomic risks of placement of half-pins in this area; no safe corridors have been defined. Additionally, pins are placed near the hip capsule and no studies exist defining the superior extent of the hip capsule which potentially may be violated by placing half-pins in this location. The purposes of the current study were to evaluate the neurovascular risks and accuracy of fluoroscopically guided percutaneous placement of supra-acetabular half-pins, and to evaluate the anatomic superior extent of the hip capsule. Ten fresh frozen cadaveric pelves were used. A 5-mm half-pin was placed in the supra-acetabular bone under fluoroscopic guidance. Iliofemoral dissection was done and the proximity of the half-pin to local neurovascular risks was measured with a caliper. The hip capsule was exposed and the superior extent of the hip capsule was measured. Intraosseous pin placement was evaluated by direct observation. Nine pins were completely in bone, one had partially exited posteriorly and laterally. The lateral femoral cutaneous nerve was at risk with a mean distance of 10 mm (range, 2-25 mm) from the half-pins. The femoral nerve and femoral artery were not at risk. The average superior extent of the hip capsule was 16 mm above the joint (range, 11-20 mm). Half-pins can be placed accurately and safely in the supra-acetabular region using percutaneous techniques, appropriate soft tissue sleeves, and fluoroscopic guidance. Insertion of pins at least 2 cm above the hip is recommended to avoid potential hip capsule penetration.

Bone Nails↗
PubMed2003

An innovative method to enhance interaction during lecture sessions.

The B. P. Koirala Institute of Health Sciences, Dharan, is following an innovative hybrid curriculum. Conventional lectures are replaced by "structured interactive sessions" (SIS). SIS involves increased interchange between teachers, students, and lecture contents by proper planning and organized efforts. It can promote active learning and heighten attention and motivation. The present study was conducted to enhance active interactions during such sessions. The students were divided into two groups and asked to come prepared for the lectures. Students were encouraged to ask questions and interact informally during lectures. A scoreboard was maintained, and student feedback was taken at the end of the lecture block. The entire student response was reduced to a student acceptability index (SAI). Our results show a statistically significant increase in interactions per student per day. A majority of the responses in the questionnaire and SAI were favorable. Specific comments and suggestions of students were also positive. These results show that simple innovative techniques enhance the interactions during a lecture session.

Cardiology↗
PubMed2003

In-vivo therapeutic efficacy trial with artemisinin derivative, buparvaquone and imidocarb dipropionate against Babesia equi infection in donkeys.

The therapeutic efficacy of imidocarb, artesunate, arteether, buparvaquone and arteether+buparvaquone combination was evaluated against Babesia equi of Indian origin in splenectomised donkeys with experimentally induced acute infection. Efficacies of these drugs were tested by administering each drug or drug combination to groups of donkeys (having three donkeys each group). One group of donkey was kept as untreated control for comparing the results. Parasitaemia, haematology (WBC, RBC, PCV, granulocytes and haemoglobin), biochemical parameters (SAST, SALT, alkaline phosphatase, albumin/globulin ratio) were monitored at regular intervals. Individually, arteether and buparvaquone were found to have no parasite clearing efficacy and the treated animals died within 5-6 days after showing high parasitaemia and clinical symptoms of the disease. However, artesunate treated animals were able to restrict the parasite multiplication but only during the treatment period. Animals treated with imidocarb and arteether+buparvaquone combination were able to clear the parasite from the blood circulation after 2-5 days post-treatment (PT). After 55-58 days PT, recrudescence of B. equi parasite was observed in both these groups and a mean survival period of 66 days and 69 days, respectively, was recorded in these groups. Results of haemato-biochemical parameters had shown that imidocarb had deleterious effect on the liver function while on the other hand arteether+buparvaquone combination was found to be safe. This limited study indicates that arteether+buparvaquone combination could be a better choice than imidocarb for treating B. equi infection, but further trials are required in detail.

Animals↗
PubMed2003

Drug treatment of stable angina pectoris in the elderly: defining the place of calcium channel antagonists.

Chronic stable angina pectoris (CSAP) resulting from coronary artery disease (CAD) is common in elderly patients, and significantly reduces their quality of life. Myocardial revascularisation procedures in this age group entail significant risks, largely related to comorbidities rather than advanced age itself. Coronary artery anatomy is more likely to be technically unsuitable for revascularisation and angina more resistant to drug treatment. Therefore, elderly patients often take combinations of antianginal drugs. Calcium channel antagonists (CCAs) are effective antianginal drugs first introduced for clinical use in the late 1970's. They reduce myocardial ischaemia by both causing vasodilatation of coronary resistance vessels and reducing cardiac workload (negative inotropic effect). However, adverse effects related to abrupt arterial vasodilatation limited the tolerability of these short acting 'first generation' drugs (nifedipine, verapamil and diltiazem). Furthermore, short acting nifedipine may occasionally increase both the frequency of angina pectoris and mortality in patients with CAD. Since then, long acting formulations of first generation agents and new chemical entities (second and third generation drugs) have been developed. These are well tolerated and effective at attenuating both myocardial ischaemia and the frequency and severity of angina pectoris in most patients with stable CAD. Current guidelines on the drug treatment of CSAP propose that beta-adrenoceptor antagonists (beta-blockers) should be used as first line medication primarily for their prognostic benefits, and that CCAs need only be introduced if beta-blockers are not tolerated, contraindicated or ineffective. Despite this, there is a wealth of evidence from clinical trials that demonstrate equal antianginal efficacy for CCAs and beta-blockers. The presence of chronic heart failure and prior myocardial infarction are clear indications for the use of beta-blockers in preference to CCAs for the treatment of CSAP. However, in patients with both CSAP and hypertension, second and third generation CCAs may offer prognostic benefits of similar magnitude to those provided by beta-blockers. Therefore, antianginal drug therapy must be tailored to the individual needs and comorbidities of each elderly patient.

Aged↗
PubMed2003

Quantitative evaluation of AgNORs in bone tumours.

AIMS: Primary tumours of bone present a significant diagnostic and therapeutic challenge at times. Silver stained nucleolar organiser regions (AgNORs) have been widely used in a variety of tissues but with a limited study on bone tumours. Our study was aimed at the evaluation of AgNOR count in various neoplastic lesions of bone. METHODS: : One hundred biopsies of bone lesions were included in this study. Five samples of foetal lumbar vertebrae obtained from foetal autopsies were taken as control. The study included 58 males and 42 females with age ranging from 5 to 70 years. Fifty-two cases were malignant while 48 were benign in nature. Silver staining for nuclear organiser regions was performed according to one-step silver staining technique in these cases. NORs seen as black dots were counted in the nuclei of 100 cells. RESULTS: Our study revealed that the mean count was highest in malignant lesions (4.00+/-0.69) compared with benign lesions (2.16+/-0.43) and normal bone (1.32+/-0.14). Statistically, the AgNOR count showed a significant difference (P<0.001) in all these lesions. CONCLUSIONS: The results of the current study revealed that malignant lesions had a greater mean AgNOR count than benign tumours and the normal bone. Thus, quantification of AgNORs strongly correlates with the type as well as aggressiveness of the bone tumour and is diagnostically useful in tumour differentiation.

Adolescent↗
PubMed2002

A complex of the IL-1 homologue IL-1F7b and IL-18-binding protein reduces IL-18 activity.

IL-1F7 was discovered in expressed sequence tag databases as a member of the increasing family of proteins sharing sequence homology to IL-1alpha/beta, IL-1Ra, and IL-18. In the present study using immunohistochemical staining, IL-1F7 was localized in human peripheral monocytic cells, suggesting its role in immune regulation. Recombinant human IL-1F7b was shown to bind to the IL-18Ralpha but without IL-18 agonistic or antagonistic function. Using chemical cross-linking, we observed that, unlike IL-18, IL-1F7b fails to recruit the IL-18Rbeta chain to form a functionally active, ternary complex with the IL-18Ralpha chain. IL-1F7b shares two conserved amino acids with IL-18 (Glu-35 and Lys-124), which participate in the interaction of IL-18 with the IL-18Ralpha chain as well as the IL-18-binding protein (IL-18BP), a secreted protein that neutralizes IL-18 activity. In testing whether IL-1F7b interacts with IL-18BP, we unexpectedly observed that IL-1F7b enhanced the ability of IL-18BP to inhibit IL-18-induced IFNgamma by 25-30% in a human natural killer cell line. This effect was observed primarily at limiting concentrations of IL-18BP (3.12-12.5 ng/ml) and at a 50- to 100-fold molar excess of IL-1F7b. Similar results were obtained by using isolated human peripheral blood mononuclear cells. To study the molecular basis of this effect we performed binding studies of IL-1F7b and IL-18BP. After cross-linking, a high molecular weight complex consisting of IL-1F7b and IL-18BP was observed on SDS/PAGE. We propose that after binding to IL-18BP, IL-1F7b forms a complex with IL-18Rbeta, depriving the beta-chain of forming a functional receptor complex with IL-18Ralpha and thus inhibiting IL-18 activity.

Amino Acid Sequence↗