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Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 235 records · Page 13Linked to original sources
PubMed1997

U.S. Army soldiers' perceptions of arthropod pests and their effects on military missions.

A survey was conducted to determine the effects of biting and stinging arthropods on military personnel, operations, and training. Nearly 70% of respondents reported experiencing problems attributable to arthropods. Arthropods obstructed movement and field position, prevented concealment and cover, disrupted maneuvers, and caused panic. Twenty percent of respondents reported attendance at sick call for treatment of bites or stings, and 4% were hospitalized or assigned to quarters. Median lost time was 2 days. Bee, wasp, and ant stings and spider and chigger bites were the most frequent causes of lost time. Additional training on biting and stinging arthropods, use of repellents and other personal protective measures, first aid for bites and stings, and conditions requiring medical attention is needed in field units to enhance mission performance and reduce time lost because of arthropods. Materials for treatment of bites and stings should be included in first-aid kits issued for field use.

Animals↗
PubMed1997

Evolution of repellent tolerances in representative arthropods.

Eight commercial insect repellents were tested against Ornithodoros parkeri (Acari: Argasidae), Dermacentor variabilis (Acari: Ixodidae), Aedes aegypti (Diptera: Culicidae), and Xenopsylla cheopis (Siphonaptera: Pulicidae). Patterns of tolerance to the test materials were distinctive for each test species. Levels of tolerance were coded as character state 0 (sensitive), 1 (intermediate), or 2 (tolerant) and mapped on a cladogram reflecting the accepted classification of the test species. Character state 0 was regarded as primitive, as indicated by the ontology of repellent tolerances in ticks. Aedes aegypti was least evolved and X. cheopis was most evolved in tolerance to repellents. Multiple parallelism of the arachnid and X. cheopis lines occurred in the evolution of the observed tolerances.

Aedes↗
PubMed1996

Fine-needle aspiration cytodiagnosis of adenoid cystic carcinoma of the breast.

Adenoid cystic carcinoma (ACC) of the breast is a rare breast cancer with a good prognosis. Its morphology is identical to its counterpart in the salivary glands. In this brief report, two cases of ACC of the breast are presented in which the diagnosis was established on a fine-needle aspiration cytology (FNAC) and correlated with subsequent examination of cell blocks of aspirate and tissue. The cytodiagnostic criteria for ACC of the breast are discussed.

Adolescent↗
PubMed1996

Aspiration cytodiagnosis of a rare carcinoma of breast with bizarre malignant giant cells.

On a review of our experience with 14,526 fine-needle aspiration cytology (FNAC) studies of the breast which were done from January 1983 to July 1994, five cases of the rare breast carcinoma were diagnosed in which bizarre, pleomorphic malignant giant cells formed an integral part of the tumour. In all the five cases, immunocytochemical studies were done on aspirated samples. Based on our present findings, in FNAC samples and in keeping with the findings recently described by us in a case, it is stressed that the bizarre malignant giant cells in this type of breast carcinoma are indeed of an epithelial origin. The differential diagnoses of other breast conditions in which giant cells may be seen in FNAC samples is appropriately discussed.

Adult↗
PubMed1996

Finger printing of Mycobacterium tuberculosis in patients with intracranial tuberculomas by using in vivo, ex vivo, and in vitro magnetic resonance spectroscopy.

In vivo, ex vivo, and in vitro proton magnetic resonance spectroscopy was performed in 12 patients with intracranial tuberculomas with an aim of detecting the biochemical constituents of Mycobacterium tuberculosis in a granuloma. One dimensional (1D) single pulse and spin-echo sequences and 2D correlative spectroscopy were used for the ex vivo study to confirm the resonances seen on in vivo study. Spectroscopic studies of the perchloric acid and lipid extract of granuloma and M. tuberculosis were performed to look for similarity of resonance. In vivo study showed the presence of lipids at 0.9, 1.3, 2.0, 2.8 ppm, and phosphoserine at 3.7 ppm. All these resonances were confirmed on ex vivo study. In addition, distinct resonances of serine and phenolic lipids were seen on ex vivo and in vitro study of tuberculous granuloma, which have not been observed in other intracranial tumors. Lipid extract of granuloma and M. tuberculosis showed phenolic lipids at 7.1 and 7.4 ppm, a constituent of the cell wall of the bacteria in a tuberculoma. It appears that it may be possible to finger print the biochemicals of the cell wall of M. tuberculosis in a tuberculous granuloma and thus may help in detection and diagnosis of such lesions.

Amino Acids↗
PubMed1996

An enzyme immunoassay based micro-neutralization test for titration of antibodies to human cytomegalovirus (CMV) and its correlation with direct ELISA measuring CMV IgG antibodies.

An ELISA-based micro-neutralization (Nt) test in MRC-5 cells for titration of neutralizing antibodies against human cytomegalovirus (CMV) in human plasma and preparations of immune globulins was developed to eliminate microscopic reading of cytopathic effect (CPE), a process that is subjective and time consuming. Un-neutralized CMV from the Nt reaction and grown in MRC-5 cells as per the standard micro-Nt test was coated in the same plates by various methods and CMV antigen was quantified by polyclonal or monoclonal CMV antibodies. Optimal coating of plates with CMV antigen (100 TCID50 of virus grown on MRC-5 cells for 7 days) was obtained by freezing/thawing of virus infected MRC-5 cells in phosphate buffered saline, ph 7.2. The CMV antigen treated sequentially with CMV monoclonal antibody to late nuclear protein antigen, goat anti-mouse IgG3 alkaline phosphatase conjugate and phosphatase substrate gave an absorbance of 1 at 410 nm wavelength whereas uninfected MRC-5 cells treated under similar conditions did not show any absorbance. The optimal Nt reaction occurred at 37 degrees C for 1-2 h and was unaffected by complement. At 4 degrees C, CMV was inactivated in 1-2 h. The antibody titres were affected by the virus dose used in the Nt test over a range of 20 to 798 TCID50. When the titre was determined against a reference serum, the effect of virus dose on the Nt titre was reduced. Complete neutralization virus read microscopically correlated with ELISA absorbance of < 0.1. CPE produced by approximately 1 TCID50 of CMV showed an absorbance of 0.1 or more. The correlation coefficient (r) between Nt titres and CMV IgG antibodies determined by ELISA was 0.69 (P < 0.001) for 257 human plasma samples and 0.85 (P < 0.001) for 50 immune globulin preparations.

Antibodies, Viral↗
PubMed1996

IgG subclass antibodies to human cytomegalovirus (CMV) in normal human plasma samples and immune globulins and their neutralizing activities.

An enzyme-linked immunoabsorbent assay (ELISA) was developed for quantitation of IgG subclass antibodies to human cytomegalovirus (CMV) in human serum or plasma samples and in immune globulin (IG) preparations. The assay was based on the parallel titration of known concentrations of purified IgG subclass myeloma proteins and a specific CMV antiserum. The purified IgG subclass myeloma proteins were captured on an ELISA plate pre-coated with anti-human kappa, anti-human lambda or a mixture of anti-human kappa and lambda antibodies and the specific antiserum was titrated against CMV antigen coated on the plate. IgG subclass antibodies, captured or bound to antigen, were quantitated with IGG subclass heavy chain specific monoclonal antibodies. The method was highly reproducible, specific and sensitive. Using this method, 257 human plasma samples and 50 IG preparations were assayed for CMV specific IgG subclass and IgM antibodies. The major IgG subclass antibody to CMV was IgG1 which represented more than 96% of CMV IgG antibodies, followed by IgG3 (mean CMV IgG3 antibody content was 3% of IgG antibodies in IG preparations and 1.8% in plasma samples). A majority of the samples had low levels of IgG2 antibodies and a few samples exhibited low levels of IgG4 antibodies. IG preparations showed very low levels of CMV IgM antibodies whereas plasma samples had 14.2% of CMV antibodies (IgG and IgM) as IgM antibodies. Virus neutralizing (Nt) activity of these samples showed a significant correlation with CMV IgG1 antibodies. Nine samples of plasma and IGs were further evaluated for Nt activity of IgG1 and IgG3 antibodies by separating IgG3 from the rest of the antibodies with protein A agarose. IgG3 antibodies showed much higher Nt activity than IgG1 antibodies suggesting that enrichment of IgG3 antibodies in IG preparations may be useful in preparing CMV specific IG.

Antibodies, Viral↗
PubMed1996

Compressive myelopathy in fluorosis: MRI.

We examined four patients with fluorosis, presenting with compressive myelopathy, by MRI, using spin-echo and fast low-angle shot sequences. Cord compression due to ossification of the posterior longitudinal ligament (PLL) and ligamentum flavum (LF) was demonstrated in one and ossification of only the LF in one. Marrow signal was observed in the PLL and LF in all the patients on all pulse sequences. In patients with compressive myelopathy secondary to ossification of PLL and/or LF, fluorosis should be considered as a possible cause, especially in endemic regions.

Adult↗
PubMed1996

Problems in distinguishing spinal tuberculosis from neoplasia on MRI.

We reviewed MRI studies of 60 patients presenting with extradural compressive myeloradiculopathy secondary to vertebral disease to assess the imaging features which may help in differentiating tuberculous from neoplastic disease. Spin-echo T1-, proton density-and T2-weighted images were available for all patients and fast low-angle shot images with a low flip angle for 21 patients. Contrast-enhanced images were available for 28 patients. There were 41 patients with tuberculosis and 19 patients with neoplastic disease (metastases 11, lymphoma 6, plasmacytoma 1, and giant cell tumour 1). Discovertebral disease with or without involvement of the posterior arch was a feature not only of tuberculous spondylitis (30 patients) but also of metastases (6). The remaining 11 patients with tuberculosis had "atypical" involvement (vertebral body with or without posterior arch in 8 and posterior arch alone in 3) described as typical of neoplasms. This "typical" involvement was seen in metastases (5), lymphoma (6) and the 2 primary bone tumours. The presence of an abscess helped in differentiating tuberculosis from neoplasia in 22 of the 41 patients with tuberculosis and was absent in all with neoplasms. The presence of bone fragments in 16 patients (8 with and 8 without an abscess) was found to be specific for tuberculosis. In the absence of an abscess or bone fragments, image-guided biopsy is essential to establish the diagnosis.

Adenocarcinoma↗
PubMed1996

Immune response to polyvalent melanoma cell vaccine in AJCC stage III melanoma: an immunologic survival model.

BACKGROUND: Our polyvalent, allogeneic melanoma cell vaccine (MCV) induces immunoglobulin M (IgM) and immunoglobulin G (IgG) class antibodies to a 90-kDa glycoprotein melanoma-associated antigen (MAA). Additionally, MCV induces delayed-type hypersensitivity (DTH) responses that we previously correlated with survival. We hypothesized that early DTH responses to MCV and early humoral responses to the 90-kDa MAA expressed on MCV cells may be predictive of overall survival. We tested this hypothesis by monitoring immunologic profiles in 59 patients with melanoma who were receiving MCV after surgical resection of regional lymph node or soft-tissue metastases. METHODS: Blood was drawn before vaccine administration, biweekly for 6 weeks, and then monthly. DTH to MCV was recorded at 0, 2, 4, and 8 weeks of MCV therapy. Mean antibody titers during the first 6-week interval were calculated. Changes in DTH were calculated as the difference between peak and prevaccine values (delta DTH). RESULTS: At a median follow-up of 75.6 months (range 5-138), univariate analysis assigned prognostic significance to gender (p = 0.046), lymph node involvement (p = 0.024), delta DTH (p = 0.044), mean anti-90-kDa MAA IgG (p = 0.0009), and mean anti-90-kDa MAA IgM (p = 0.0014). In multifactorial analysis, only the three immunologic variables significantly impacted survival (p = 0.046, 0.0005, and 0.0053, respectively). A mathematical model based on delta DTH and mean anti-90-kDa MAA IgG and IgM titers closely approximated the observed individual and overall survival rates. CONCLUSIONS: The correlation between overall survival and initial humoral/cellular immune responses to MCV immunotherapy may be useful in selecting patients most likely to benefit from prolonged adjuvant immunotherapy.

Adolescent↗
PubMed1996

Differences in hydration state of nucleus and cytoplasm of the amphibian oocyte.

Nuclear magnetic resonance (NMR) microimaging and proton relaxation times were used to monitor differences between the hydration state of the nucleus and cytoplasm in the Rana pipiens oocyte. Individual isolated ovarian oocytes were imaged in a drop of Ringer's solution with an in-plane resolution of 80 microm. Proton spin echo images of oocytes arrested in prophase I indicated a marked difference in contrast between nucleoplasm and cytoplasm with additional intensity gradations between the yolk platelet-rich region of the cytoplasm and regions with little yolk. Neither shortening taue (spin echo time) to 9 msec (from 18 msec) nor lengthening taur (spin recovery time) to 2 sec (from 0.5 sec) reduced the observed contrast between nucleus and cytoplasm. Water proton T1 (spin-lattice) relaxation times of oocyte suspensions indicated three water compartments that corresponded to extracellular medium (T1 = 3.0 sec), cytoplasm (T1 = 0.8 sec) and nucleoplasm (T1 = 1.6 sec). The 1.6 sec compartment disappeared at the time of nuclear breakdown. Measurements of plasma and nuclear membrane potentials with KCl-filled glass microelectrodes demonstrated that the prophase I oocyte nucleus was about 25 mV inside positive relative to the extracellular medium. A model for the prophase-arrested oocyte is proposed in which a high concentration of large impermeant ions together with small counter ions set up a Donnan-type equilibrium that results in an increased distribution of water within the nucleus in comparison with the cytosol. This study indicates: (i) a slow exchange between two or more intracellular water compartments on the NMR time-scale, (ii) an increased rotational correlation time for water molecules in both the cytoplasmic and nuclear compartments compared to bulk water, and (iii) a higher water content (per unit dry mass) of the nucleus compared to the cytoplasm, and (iv) the existence of a large (about 75 mV positive) electropotential difference between the nuclear and cytoplasmic compartments.

Animals↗
PubMed1996

Spinal segmental maldevelopment with a dermal sinus.

Segmental spinal dysgenesis is a rare form of spinal dysraphism. We report a case of segmental hypoplasia of the spinal cord extending from T6 to L1 vertebral levels, with a dorsal dermal sinus, diagnosed by spinal sonography and MRI and confirmed at surgery. The probable pathogenesis is suggested.

Diagnosis, Differential↗
PubMed1996

Adjuvant properties of non-phospholipid liposomes (Novasomes) in experimental animals for human vaccine antigens.

Non-phospholipid liposomes composed of dioxyethylene cetyl ether, cholesterol and oleic acid were evaluated as adjuvants with human vaccine antigens, tetanus toxoid (TT) and diphtheria toxoid (DT), in mice and rabbits. Antigens encapsulated in or mixed with liposomes elicited antitoxin levels similar to those elicited by antigens given with Freund's adjuvant or adsorbed onto aluminum phosphate. All liposomal antigen preparations, antigen given with Freund's adjuvant or adsorbed onto aluminum phosphate, elicited significantly higher IgG antibodies and antitoxin levels than soluble antigens in mice after a single injection and in rabbits after each of three injections. TT encapsulated in liposomes elicited sustained anti-TT IgG antibody levels in mice after a single injection as compared to TT mixed with liposomes. TT mixed with or encapsulated within liposomes containing monophosphoryl lipid A/squalene or squalene alone, as well as aluminum phosphate adsorbed TT elicited greater primary responses in mice than TT mixed with or encapsulated within plain liposomes. Liposomal TT preparations produced a slightly higher anamnestic response in mice than aluminum phosphate adsorbed TT. Subclass analysis of anti-TT antibodies showed that the majority of the antibodies belong to IgG1 subclass. Liposomal TT preparations, particularly those with encapsulated monophosphoryl lipid A/squalene or squalene alone, consistently elicited higher levels of anti-TT IgG2a and IgG2b than aluminum phosphate adsorbed or soluble TT. None of the preparations elicited IgG3 or IgM antibodies. It appears that non-phospholipid liposomes are as potent adjuvants as the currently employed adjuvant for human vaccines (aluminum phosphate) or a benchmark adjuvant for experimental immunology (Freund's adjuvant), and may be able to modulate the immune response towards the Th1 type.

Adjuvants, Immunologic↗
PubMed1996

Invasive fungal infections in renal transplant recipients.

In a retrospective analysis, 18 instances of invasive fungal infections were observed in 512 (3.5%) renal transplant recipients. These included candidiasis (8), aspergillosis (5), cryptococcosis (3) and zygomycosis (2). All patients with candidiasis had Candida isolated from blood and one or more additional sites. One of them had superadded fungaemia with Torulopsis glabrata. Pulmonary disease in four and subcutaneous infection in one were encountered in the five patients with aspergillosis. Central nervous system involvement in two and cutaneous lesion in one were the findings in patients with cryptococcosis. Zygomycosis involved the lung in one and the allograft itself in the other. Prolonged fever not responding to antibacterial drugs was the most common clinical presentation. Fungal infections occurred during the first 4 months in 10 (55.5%) and 12 to 108 months in eight (44.5%) patients. Infections with cytomegalovirus and hepatitis viruses were concommitantly present in 12 (66.7%) and eight (44.5%) patients respectively. Fourteen episodes of fungal infections (77.8%) occurred in live unrelated kidney recipients who formed only 48% of our total transplant population. Nine patients were treated with systemic and/or local amphotericin B and six with amBisome. Fluconazole was administered alone in three and in combination with amphotericin B in two. Fourteen patients died but mortality was only directly attributable to fungal infection in 11. We conclude that invasive fungal infections continue to be an important cause of morbidity and mortality in renal transplant recipients. A high index of suspicion. prompt diagnosis and early institution of specific antifungal therapy are needed.

Adult↗
PubMed1996

Post-transfusion hepatitis type B following multiple transfusions of HBsAg-negative blood.

BACKGROUND/AIMS: Post-transfusion hepatitis continues to occur, though with decreasing frequency, even after screening donor blood for HBsAg, anti-HBc, anti-HCV and alanine aminotransferase activity. Data from developing countries on the frequency and type of post-transfusion hepatitis are scarce. We undertook this prospective study to determine the incidence and type of post-transfusion hepatitis at our center after transfusion of blood negative for HBsAg by ELISA. METHODS: Forty-one patients undergoing open-heart surgery, who had received 3 or more units of HBsAg-negative blood, were followed up. Serum samples of donor units transfused to recipients who developed post-transfusion hepatitis-B were subjected to HBV DNA amplification by the polymerase chain reaction, using two sets of X-gene specific primers which amplified a 250-bp fragment of the HBV DNA. RESULTS: We found that six of the 41 patients (14.6%) developed post-transfusion hepatitis; four of them (66.6%) developed icteric post-transfusion hepatitis B, whereas two (33.3%) developed anicteric post-transfusion hepatitis C. These six recipients received a total of 48 units of blood and 30 of these 48 units could be subjected to HBV DNA amplification by polymerase chain reaction. Eleven donor samples were polymerase chain reaction positive and had been transfused to three of the four patients who had developed post-transfusion hepatitis B. CONCLUSIONS: We conclude that post-transfusion hepatitis B continues to be the most common cause of post-transfusion hepatitis in India. Screening of donor units for HBsAg by ELISA does not exclude all blood units infectious for hepatitis B virus. Additional measures to ensure safety of blood supply should be sought.

Cardiopulmonary Bypass↗
PubMed1996

In vivo distribution of radioactivity in mice after injection of biodegradable polymer microspheres containing 14C-labeled tetanus toxoid.

Radiolabeled tetanus toxoid (TT) was prepared by detoxifying chromatographically purified tetanus toxin with 14C-labeled formaldehyde. 14C-TT was encapsulated inside poly (D,L-lactide-co-glycolide, 50/50) microspheres (MS) of varying average size (approximately 10 microns and approximately 50 microns). Balb/c mice were injected subcutaneously with 5 Lf (approximately 15 micrograms) of 14C-TT, encapsulated in MS, mixed with blank MS without encapsulated antigen, as soluble antigen or adsorbed onto aluminum phosphate (AlPO4) and radioactivity was monitored at the site of injection, draining lymph nodes, blood, liver, spleen, and kidneys at various intervals. At one day, approximately 95% and 90% radioactivity disappeared from site of injection for soluble TT or blank MS mixed TT and AlPO4 adsorbed TT, respectively, whereas approximately 55% and 70% radioactivity disappeared from site of injection for MS of average size approximately 50 microns and approximately 10 microns, respectively. By 7 days, 99% of radioactivity disappeared from site of injection for soluble TT or blank MS mixed TT, whereas 2-3% radioactivity persisted at the site of injection for AlPO4 adsorbed TT for 4 weeks. In contrast, approximately 20% radioactivity stayed at the site of injection for MS injected mice up to 4 weeks. At all time points, large MS (approximately 50 microns) showed more radioactivity at the site of injection than small MS (approximately 10 microns). Other organs showing radioactivity were draining lymph nodes and kidneys. Small MS with encapsulated TT showed highest level of radioactivity in lymph nodes at 4 h. In kidneys, soluble and AlPO4 adsorbed TT showed a peak of radioactivity at 4 h whereas TT encapsulated in MS showed a peak of radioactivity at 7 days. These results indicate that AlPO4 did not act as a depot for TT at the site of injection, but TT encapsulated in MS did form a depot for approximately 1 month.

Animals↗