PubMed Health⌕ Search

Biomedical subjects

N Bhardwaj

Publications and source records attributed to N Bhardwaj.

At least 19 recordsLinked to original sources
PubMed2025

HLA-E and NKG2A Mediate Resistance to BCG Immunotherapy in Non-Muscle-Invasive Bladder Cancer.

Bacillus Calmette-Guérin (BCG) is the first-line therapy for high-grade non-muscle-invasive bladder cancer (NMIBC), yet many patients experience recurrence due to immune evasion. We identify HLA-E and NKG2A as mediators of adaptive resistance involving chronic activation of NK and T cells in BCG-unresponsive tumors. Prolonged IFN-γ exposure enhances HLA-E and PD-L1 expression on recurrent tumors, accompanied by the accumulation of NKG2A+ NK and CD8 T cells. HLA-Ehigh tumor cells preferentially cluster near CXCL12-rich stromal regions with dense effector cell presence, underscoring a spatially segregated tumor architecture. Although cytotoxic lymphocytes retain effector potential, their activity is restrained by HLA-E/NKG2A and PD-L1/PD-1 pathways located in their immediate neighborhood within the bladder tumor microenvironment. These data reveal a spatially organized immune escape program that limits anti-tumor immunity. Our findings support dually targeting NKG2A and PD-L1 checkpoint blockade as a rational, bladder-sparing strategy for patients with BCG-unresponsive NMIBC.

BCG-unresponsive↗
PubMed2006

Anti-neoplastic effect of chicken anemia virus VP3 protein (apoptin) in Rous sarcoma virus-induced tumours in chicken.

The anti-neoplastic effect of chicken anemia virus VP3 protein (apoptin) was investigated in vitro in Rous sarcoma virus (RSV)-transformed chicken embryo fibroblast (CEF) cells and in RSV-induced tumours of specific-pathogen-free (SPF) chicks in vivo. The apoptin gene was cloned in the pVAX expression vector and in vitro expression of the recombinant vector pVAX-CAV-VP3 was confirmed. Two groups of SPF chicks, each containing ten chicks, were used. Chicks in groups I and II were inoculated with RSV at 1 day old. Group I served as the control, receiving pVAX vector without insert, and group II received recombinant vector pVAX-CAV-VP3 containing the apoptin gene, on day 10. An in vitro study confirmed that apoptin induced apoptosis in RSV-transformed CEF cells, which was demonstrated by observation of the characteristic changes of apoptosis using the indirect immunofluorescence technique and acridine orange/ethidium bromide staining. In vivo study also indicated that apoptin induced apoptosis and caused tumour regression by an intratumoral-delivery method. Apoptotic changes, such as nuclear condensation, fragmentation of the chromatin and formation of apoptic bodies in the tumour cells, were demonstrated by histopathology and acridine orange/ethidium bromide staining. No apoptotic changes were seen in the tumours of the control group. The results of the present study showed that apoptin had an anti-neoplastic effect in vivo and in vitro in RSV-induced tumours. The anti-neoplastic effect is due to apoptin-induced apoptosis. Further improvements in the dose, delivery method and delivery frequency of the apoptin-expressing recombinant vector could help to develop apoptin as an anti-neoplastic drug.

Animals↗
PubMed2006

Autophagic vacuolar myopathy in twin girls.

Hereditary autophagic vacuolar myopathy (AVM) may occur in several diseases including the rimmed vacuolar myopathies, acid maltase deficiency, Danon disease, infantile autophagic vacuolar myopathy and X-linked myopathy with excessive autophagy (XMEA). In the latter three conditions the vacuoles are lined by membranes with sarcolemmal features. We present two unusual cases of autophagic vacuolar myopathy in twin girls born at term with no family history of neurological disease. After initial normal developmental milestones they developed progressive leg weakness and wasting with contractures from the age of 12 years. Investigations showed raised CK, normal female karyotype, normal acid maltase activity, normal nerve conduction and myopathic EMG features. Frozen sections of skeletal muscle were stained using routine tinctorial and histochemical methods. Immunohistochemical staining for spectrin, merosin, dystrophin, complement membrane attack complex and sarcoglycans was performed and ultrastructural examination undertaken. Direct sequence analysis of the lamp-2 gene using genomic DNA extracted from lymphocytes was performed. Histological analysis of the muscle biopsies demonstrated myofibres with vacuoles lacking glycogen and lipid many of which were delineated using immunohistochemistry for merosin, dystrophin and sarcoglycans. Ultrastructural examination showed duplication of the myofibre basal lamina with associated autophagic material. Vacuoles within myofibres were either membrane bound containing autophagic material or lined by plasma membrane and basal lamina. Intermyofibrillar glycogen was increased. Sequence analysis of the coding region and intron/exon boundaries of the lamp-2 gene was normal. This is the first report of female cases of AVM with sarcolemmal features. We suggest that these patients may represent manifesting carriers of XMEA, or alternatively, a new form of disease with a similar phenotype having autosomal recessive inheritance.

Adolescent↗
PubMed2006

Effect of scalp block on postoperative pain relief in craniotomy patients.

The efficacy of scalp nerve block using 0.5% bupivacaine with adrenaline for postoperative pain relief in craniotomy patients was evaluated in 40 ASA I or II adult patients undergoing supratentorial craniotomy. A standard general anaesthesia technique was followed. Patients were randomly divided into two groups. Group B received 0.5% bupivacaine with 1:400,000 adrenaline and group S received normal saline with 1:400,000 adrenaline, both after skin closure. Postoperative pain was assessed at 30 seconds and 1, 2, 4, 6, 8 and 12 hours using a numerical rating scale. Diclofenac IM was administered as rescue analgesia if patients reported a numerical rating scale of 40 or more. Tramadol IV was administered as second rescue analgesia. Sixty per cent of patients in group S experienced moderate to severe pain (numerical rating scale of 40 or more) at some time during the first 12 postoperative hours in comparison to 25% patients in group B. Median pain scores were significantly lower in group B for up to 6 hours. Significantly more patients were pain free up to four hours in group B. Median duration for the requirement of first dose of diclofenac was longer in group B compared to group S (360 min vs 30 min, P < 0.01). The number of doses of diclofenac (5 vs 19) was significantly lower in group B compared to group S (P < 0.01). Tramadol was required by six patients in group S only. Scalp nerve block using 0.5% bupivacaine with 1:400,000 adrenaline decreases the incidence and severity of postoperative pain in patients undergoing supratentorial craniotomy.

Adrenergic Agonists↗
PubMed2005

Biological and molecular characterization of chicken anaemia virus isolates of Indian origin.

In the present study, four chicken anaemia virus (CAV) isolates (CAV-A, -B, -E and -P) recovered from different geographical regions of India were characterized. CAV genome of 1,766 bp nucleotide region containing the complete coding region of VP2 and VP3 proteins, and partial coding region of VP1 protein were sequenced. The nucleotide and deduced amino acid sequence of the Indian CAV isolates were aligned and compared with CAV isolates of European, Asian, American and Australian origin. Phylogenetic analysis of the Indian CAV isolates were also carried out based on the nucleotide and deduced amino acid sequences. The results indicated that Indian isolates were genetically evolved from different parts of the world. Indian isolate, CAV-A was found closely related to European Cux-1 strain, CAV-B and -P were closely related to Bangladesh BD-3 strain and CAV-E was closely related to Australian 704 strain. The pathogenicity of the four CAV isolates was studied in day-old specific pathogen free (SPF) chicks. Day-old SPF chicks (n=50) were divided into five groups comprised of 10 chicks in each group. Group 1 was kept as control and groups 2-5 were infected with each CAV isolate separately. The chicks were infected at a dose rate of 1 ml cell culture fluid (10(4.5)TCID(50)/0.1 ml) per bird intramuscularly. The clinical signs, mortality and packed cell volume (PCV) and body weight gain were recorded on 5, 10 and 15 days post-infection. At 15th day, all the birds were sacrificed and various organs, viz., thymus, bone marrow, spleen, liver and bursa were examined for gross and microscopic changes. The pathogenicity study indicated that all the CAVs except CAV-B were able to produce clinical disease and immunosuppression in young chicks whereas the isolate CAV-B produced no clinical disease but only induced immunosuppression, which was revealed by microscopic examination of the lymphoid organs. The study showed valuable information on molecular epidemiological status of CAV isolates prevalent in India for the first time.

Amino Acid Sequence↗
PubMed2005

Apoptotic cells at the crossroads of tolerance and immunity.

Clearance of apoptotic cells by phagocytes can result in either anti-inflammatory and immunosuppressive effects or prostimulatory consequences through presentation of cell-associated antigens to T cells. The differences in outcome are due to the conditions under which apoptosis is induced, the type of phagocytic cell, the nature of the receptors involved in apoptotic cell capture, and the milieu in which phagocytosis of apoptotic cells takes place. Preferential ligation of specific receptors on professional antigen-presenting cells (dendritic cells) has been proposed to induce potentially tolerogenic signals. On the other hand, dendritic cells can efficiently process and present antigens from pathogen-infected apoptotic cells to T cells. In this review, we discuss how apoptotic cells manipulate immunity through interactions with dendritic cells.

Animals↗
PubMed2004

Efficacy and acceptabilty of oral-transmucosal midazolam as a conscious sedation agent in pre-school children.

The purpose of the present study was to test the efficacy of oral-transmucosal route of administration of midazolam in young potentially un-cooperative children. A sample of 40 children up to 4 years of age with ASA I status were randomly divided into experimental and control groups of 20 each. The children in experimental group received 0.5-mg/kg-body weight midazolam mixed in strawberry syrup via the oral-transmucosal route and those in control group were given the same syrup diluted with normal saline. A class II amalgam restoration was performed and routine behavior management techniques were employed in both groups. It was found that the number of procedures successfully completed and sedation produced 15 minutes after test solution administration was significantly greater in the experimental group compared to the control group. The total treatment time was also much lesser in the experimental group children. There was no significant difference in the acceptability of the test solutions in the children of the two groups.

Administration, Oral↗
PubMed2003

Cross-presentation of cell-associated antigens by dendritic cells.

There is a strict requirement for professional antigen-presenting cells (APCs) in the generation of immunity toward most viruses. Exogenous pathways of MHC class I-restricted antigen presentation play an important role in the generation of antiviral immunity, particularly in the immune surveillance of virus-infected tissues of nonhematopoietic origin, and to bypass the detrimental effects of direct virus infection on professional APCs. The mechanisms underlying generation of antiviral immunity under these circumstances are discussed.

Animals↗
PubMed2003

Intrathecal fentanyl added to intrathecal bupivacaine for day case surgery: a randomized study.

BACKGROUND AND OBJECTIVE: The implication of intrathecal lidocaine in neurological toxicity has made intrathecal bupivacaine the commonly used drug for local anaesthesia in ambulatory surgery. However, in high doses intrathecal bupivacaine may produce a high level of sensory and motor block, and arterial hypotension; discharge from hospital may be delayed. Intrathecal opioids added to low-dose local anaesthetics produce a synergistic effect without increasing the sympathetic block or delaying discharge. The aim of our study was to identify the minimum effective dose of intrathecal fentanyl that in combination with low-dose intrathecal bupivacaine would provide adequate surgical conditions without prolonging recovery. METHODS: A prospective, single, blind, randomized study was conducted in 45 adult males scheduled for minor urological procedures using intrathecal anaesthesia on a day care basis. Patients were randomly assigned to one of three groups (n = 15 each). They received bupivacaine 0.17% 5 mg--with either fentanyl 7.5 microg (fenta-7.5), 10 microg (fenta-10) or 12.5 microg (fenta-12.5) intrathecally in a total volume of 3 mL. The quality of anaesthesia, haemodynamic stability, time to two-segment and S2 regression, time to micturition, and time to discharge were assessed. RESULTS: The time to two-segment regression and S2 regression with fenta-12.5 was significantly longer than with fenta-7.5 and fenta-10 (P < 0.01). Fenta-7.5 had a significantly higher number of failed blocks (four patients) compared with fenta-12.5 (P < 0.05). The time out of bed, time to micturition and time to discharge were significantly longer with fenta-10 and fenta-12.5 compared with fenta-7.5, and also with fenta-12.5 compared with fenta-10 (P < 0.01). Haemodynamic stability did not differ for all the drug combinations. CONCLUSIONS: Fentanyl 12.5 microg added to low-dose bupivacaine (5 mg) intrathecally provides better surgical anaesthesia and increased reliability of block than intrathecal fentanyl 7.5 or 10 microg. Haemodynamic stability was the same for all dose combinations used.

Adjuvants, Anesthesia↗
PubMed2001

Generation of high quantities of viral and tumor-specific human CD4+ and CD8+ T-cell clones using peptide pulsed mature dendritic cells.

CD4+ and CD8+ T cells are key components of immune response against tumors and viruses. Many techniques have been used to clone and expand these cells in vitro for purposes of immunotherapy. Here, we describe an improved method to obtain large quantities of tumor and virus-specific human CD4+ and CD8+ T-cell clones. T cells derived from peripheral blood mononuclear cells (PBMCs) of healthy donors were stimulated several times by peptide pulsed monocyte-derived mature dendritic cells (DCs) in the presence of exogenous cytokines. T cells specific for influenza or melanoma antigens were detected by IFN-gamma intracellular staining and were cloned by limiting dilution. Specific polyclonal T-cell populations were derived for all epitopes presented by mature DCs. Nine different populations were cloned and clones were raised from eight of them. Clonality was verified by HLA/peptide tetramer staining. With additional rounds of stimulation after the cloning procedure, it was possible to obtain from 10(9) to 10(12) of each clone. Furthermore, clones could be maintained in culture in the presence of IL-2 for at least 1 month without losing their antigen-specific reactivity (e.g. cytokine secretion, cytolytic activity and proliferation). Importantly, a majority of the CD8+ T-cell clones recognized endogenously processed antigens. This method is of value for the purposes of adoptive anti-virus or anti-tumor immunotherapy.

Amino Acid Sequence↗
PubMed2001

Tethering and tickling: a new role for the phosphatidylserine receptor.

Several receptors are implicated in apoptotic cell (AC) uptake by phagocytic cells; however, their relative dominance in mammalian systems remains to be established. New studies shed light on the role of the phosphatidyl serine (PS) receptor (PSR). Ligation of PSR by PS on AC surfaces is considered essential for signaling uptake of ACs that are tethered to phagocytes via other receptors.

Animals↗
PubMed2001

Primary tumor tissue lysates are enriched in heat shock proteins and induce the maturation of human dendritic cells.

Upon exposure to lysates or supernatants of necrotic transformed cell lines, human dendritic cells (DCs) undergo maturation. In contrast, DCs exposed to apoptotic transformed cell lines or necrotic lysates of primary cells remain immature. Analysis of supernatants of necrotic transformed cell lines showed them to be enriched in the heat shock proteins (hsp)70 and gp96, in contrast to supernatants of primary cells. Likewise, cells from a variety of primary human tumors contained considerably higher levels of hsp than their normal autologous tissue counterparts. Of the majority of human tumors enriched in hsps (hsp70 and/or gp96), their corresponding lysates matured DCs. The maturation effect of tumor cell lysates was abrogated by treatment with boiling, proteinase K, and geldanamycin, an inhibitor of hsps, suggesting that hsps rather than endotoxin or DNA were the responsible factors. Supporting this idea, highly purified, endotoxin-depleted hsp70, induced DC maturation similar to that seen with standard maturation stimuli LPS and monocyte conditioned medium. These results suggest that the maturation activity inherent within tumor cells and lines is mediated at least in part by hsps. The release of hsps in vivo as a result of cell injury should promote immunity through the maturation of resident DCs.

Apoptosis↗
PubMed2001

Immune and clinical responses in patients with metastatic melanoma to CD34(+) progenitor-derived dendritic cell vaccine.

Immunization to multiple defined tumor antigens for specific immune therapy of human cancer has thus far proven difficult. Eighteen HLA A*0201(+) patients with metastatic melanoma received injections s.c. of CD34(+)progenitor-derived autologous dendritic cells (DCs), which included Langerhans cells. DCs were pulsed with peptides derived from four melanoma antigens [(MelAgs) MelanA/MART-1, tyrosinase, MAGE-3, and gp100], as well as influenza matrix peptide (Flu-MP) and keyhole limpet hemocyanin (KLH) as control antigens. Overall immunological effects were assessed by comparing response profiles using marginal likelihood scores. DC injections were well tolerated except for progressive vitiligo in two patients. DCs induced an immune response to control antigens (KLH, Flu-MP) in 16 of 18 patients. An enhanced immune response to one or more MelAgs was seen in these same 16 patients, including 10 patients who responded to >2 MelAgs. The two patients failing to respond to both control and tumor antigens experienced rapid tumor progression. Of 17 patients with evaluable disease, 6 of 7 patients with immunity to two or less MelAgs had progressive disease 10 weeks after study entry, in contrast to tumor progression in only 1 of 10 patients with immunity to >2 MelAgs. Regression of >1 tumor metastases were observed in seven of these patients. The overall immunity to MelAgs after DC vaccination is associated with clinical outcome (P = 0.015).

Adult↗
PubMed2001

Antigen-specific inhibition of effector T cell function in humans after injection of immature dendritic cells.

Immunostimulatory properties of dendritic cells (DCs) are linked to their maturation state. Injection of mature DCs rapidly enhances antigen-specific CD4+ and CD8+ T cell immunity in humans. Here we describe the immune response to a single injection of immature DCs pulsed with influenza matrix peptide (MP) and keyhole limpet hemocyanin (KLH) in two healthy subjects. In contrast to prior findings using mature DCs, injection of immature DCs in both subjects led to the specific inhibition of MP-specific CD8+ T cell effector function in freshly isolated T cells and the appearance of MP-specific interleukin 10-producing cells. When pre- and postimmunization T cells were boosted in culture, there were greater numbers of MP-specific major histocompatibility complex tetramer-binding cells after immunization, but these had reduced interferon production and lacked killer activity. These data demonstrate the feasibility of antigen-specific inhibition of effector T cell function in vivo in humans and urge caution with the use of immature DCs when trying to enhance tumor or microbial immunity.

Adult↗
PubMed2001

Efficiency of cross presentation of vaccinia virus-derived antigens by human dendritic cells.

Dendritic cells (DC) utilize at least two pathways to process viral antigens onto MHC class I molecules. The conventional endogenous route is used to acquire antigens from both infectious and non-replicating virions. Exogenous pathways are used by DC to acquire and "cross-present" antigens derived from virus-infected donor cells that by themselves lack the ability to activate T cells directly. We analyzed the role of this pathway for antigens derived from vaccinia, a virus which inhibits DC maturation and causes extensive apoptosis of infected cells, yet is highly immunogenic. Using recombinant vaccinia virus encoding the influenza matrix protein as model vector, DC were shown to cross-present vaccinia-derived antigens from both apoptotic and necrotic infected cells to antigen-specific CD8(+) T cells. Efficient cross presentation required uptake of dead cells by immature DC and exposure to maturation stimuli, especially CD40 ligand. The responding CD8(+) T cells secreted IL-2 and IFN-gamma, proliferated and developed into cytotoxic effectors. Quantification of the cross presentation of vaccinia-derived antigens showed this pathway to be highly efficient, corresponding to a peptide pulse of 10-100 nM. While monocytes also phagocytosed apoptotic and necrotic cells, they were far less efficient at cross-presenting vaccinia-derived antigens to CD8(+) T cells. The ability of DC to cross-present vaccinia-derived antigens from infected apoptotic cells or necrotic cell lysates, bypasses the deleterious effects of direct infection of DC and provides one explanation for this pathogen's immunogenicity.

Antigen Presentation↗
PubMed2001

Dendritic cells resurrect antigens from dead cells.

Antigens that do not normally access the cytoplasm of antigen-presenting cells, such as certain tumor and viral antigens, become targets of cytotoxic T lymphocytes (CTLs). Over the past 25 years, substantial evidence has emerged for an 'exogenous' pathway for loading MHC class I molecules. Dendritic cells are potent stimulators of T-cell responses and can induce CD8(+) CTLs by phagocytosis of dead tumor or virus-infected cells. Here, Marie Larsson and colleagues discuss the role of dendritic cells in stimulating MHC class I-restricted T-cell responses by exogenous routes.

Animals↗
PubMed2001

Processing and presentation of antigens by dendritic cells: implications for vaccines.

Dendritic cells (DCs) are potent antigen-presenting cells that are specialized in initiation of T-cell immunity. DCs induce promising anti-tumor T-cell and clinical responses, apparently without significant toxicity. Under certain conditions, DCs even silence T-cell immune responses in vivo. This dual capacity to modulate the immune system uniquely positions DCs for the treatment of autoimmunity, cancer and chronic viral infections.

Adjuvants, Immunologic↗