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R K Gupta

Publications and source records attributed to R K Gupta.

At least 307 records · Page 17Linked to original sources
PubMed1995

In vivo proton magnetic resonance spectroscopy in a case of intracranial hydatid cyst.

We performed in vivo proton magnetic resonance spectroscopy (MRS) in a patient who had an intracranial hydatid cyst. Besides lactate, alanine, and acetate, a large resonance for pyruvate was observed. These findings were further confirmed by ex vivo high-resolution NMR spectroscopy of the evacuated cyst fluid, as well as of the fluid aspirated from a cyst in the liver of the same patient. The MRS pattern appeared different from that seen in other cystic lesions of the CNS. In vivo MRS may be used as an adjunct to imaging in the diagnosis of intracranial hydatid cysts. It may also have a role in monitoring drug therapy.

Brain Diseases↗
PubMed1995

Characterization of intracranial mass lesions with in vivo proton MR spectroscopy.

PURPOSE: To assess the use of in vivo proton MR spectroscopy for characterization of intracranial mass lesions and to ascertain its reliability in grading of gliomas. METHODS: One hundred twenty patients with intracranial masses were subjected to volume selective spectroscopy using stimulated echo acquisition mode (echo time, 20 and 270 milliseconds) and spin echo (echo time, 135 milliseconds) sequences. The intracranial lesions were grouped into intraaxial and extraaxial, as judged with MR imaging. Assignment of resonances was confirmed in two samples each of brain abscess, epidermoid cyst, and tuberculoma using ex vivo high-resolution MR spectroscopy. RESULTS: The in vivo spectra appeared distinct compared with normal brain in all the cases. All high-grade gliomas (n = 37) showed high choline and low or absent N-acetyl-L-aspartate and creatine along with lipid and/or lactate, whereas low-grade gliomas (n = 23) were characterized by low N-acetyl-aspartate and creatine and high choline and presence of only lactate. N-acetyl-aspartate/choline ratio was significantly lower and choline/creatine ratio was significantly higher in high-grade gliomas than in low-grade gliomas. Presence of lipids suggested a higher grade of malignancy. All metastases (n = 7) showed lipid and lactate, whereas choline was visible in only four cases. Epidermoids showed resonances from lactate and an unassigned resonance at 1.8 ppm. Meningiomas could be differentiated from schwannomas by the presence of alanine in the former. Among the infective masses, pyogenic abscesses (n = 6) showed resonances only from cytosolic amino acids, lactate, alanine, and acetate; and tuberculomas (n = 11) showed only lipid resonances. CONCLUSIONS: In vivo proton MR spectroscopy, helps in tissue characterization of intracranial mass lesions. Spectroscopy is a reliable technique for grading of gliomas when N-acetyl-aspartate/choline and choline/creatine ratios and presence of lipids are used in combination.

Adolescent↗
PubMed1995

Laboratory evaluation of a new repellent camouflage face paint.

A combined formulation of the U.S. Army's camouflage face paints and the new extended duration topical insect/arthropod repellent was tested on human volunteers to determine repellency and duration of protection (2-12 h) against Aedes aegypti and Anopheles stephensi. Under laboratory conditions (27 degrees C and 80% RH), the face paint/repellent formulation provided > or = 95% repellency or better for up to 6 h for Ae. aegypti and 8 h for An. stephensi. An analysis of variance showed no significant differences in the repellent efficacy of the 4 camouflage colors: white, green, loam, and sand.

Animals↗
PubMed1995

In vivo localized proton magnetic resonance spectroscopy of intracranial tuberculomas.

In vivo proton magnetic resonance spectroscopy (MRS) was performed in ten patients with intracranial tuberculomas with the aim of finding biochemical finger prints which may help in the noninvasive diagnosis of the disease. Diagnosis of tuberculoma was confirmed in all these cases retrospectively. Ex vivo spectroscopy of formalin fixed samples of four granulomas and a normal brain (cerebellar) tissue, was performed to confirm the in vivo resonances. The in vivo study showed resonance at 1.3 ppm and 0.9 ppm assigned to methylene group (CH2)n and terminal methyl groups (-CH3) of fatty acids respectively which was subsequently confirmed by the ex vivo study. Large resonances of fatty acids in in vivo study appeared to be due to high lipid content of caseous material. It is concluded that in vivo proton spectroscopy may be helpful in differentiating tuberculomas from other intracranial mass lesions which have diagnostic difficulties on MR imaging.

Adult↗
PubMed1995

Respiratory distress in newborn: treated with ventilation in a level II nursery.

Fifty consecutive neonates with respiratory distress persisting beyond 6 h of age were studied during a 18 month period (total deliveries 2000/y). Twenty two neonates were managed with oxygen hood with increasing oxygen concentration, 28 with continuous positive airway pressure (CPAP) ventilation using a nasal cannula. Of these babies on CPAP, 10 were shifted to intermittent positive pressure ventilation (IPPV) on a pressure limited, time cycled ventilator (Neovent, Vickers). Babies were monitored with continuous hemoglobin oxygen saturation (SaO2), hourly blood pressure and vital charting. Radial arterial blood gas analysis (ABG) was done when feasible and especially on clinical deterioration. Oxygen (FiO2 0.95) from an oxygen concentrator was used as a source of continuous supply of oxygen. Commonest cause of respiratory distress was hyaline membrane disease (18%), followed by wet lung syndromes (14%), meconium aspiration (12%), asphyxia (12%) and septicemia (8%). In 8 babies, a lung biopsy (postmortem) was done to confirm the diagnosis. Nineteen of the 50 babies with respiratory distress died, there was a survival of 50% on CPAP and 30% on IPPV. No case of oxygen toxicity or other major complications was encountered. Even with moderate resources, neonatal ventilation in a Level II nursery is a challenging task. Babies less than 1000g require aggressive measures which is not very economical in a special care baby unit (SCBU).

Female↗
PubMed1995

Melorheostosis.

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Adolescent↗
PubMed1994

The displacement of calcium from osteocalcin at submicromolar concentrations of free lead.

Lead, an environmental toxin, is known to impair some of the functional properties of osteocalcin, a small protein (MW, 5700) active in bone mineralization and resorption. To investigate a possible mechanism of lead toxicity at the molecular level, we have studied the interaction of lead with osteocalcin using 43Ca and 1H NMR. The measured 43Ca NMR linewidth as well as longitudinal relaxation rate (1/T1) of 43CaCl2 progressively increased with increasing amounts of added osteocalcin. A titration measuring 43Ca linewidth as a function of [Ca2+]/[Osteocalcin] ratio could be fitted to a single metal binding site with a dissociation constant of 7 microM. The 43Ca 1/T1 of Ca-osteocalcin decreased in the presence of Pb2+ due to competitive displacement of Ca2+ by Pb2+. The magnitude of decrease in the effect of osteocalcin on 43Ca 1/T1 in the presence of Pb2+ was consistent with the existence of only one tight divalent cation binding site. An analysis of the NMR T1 data in osteocalcin solutions containing both Pb2+ and Ca2+ yielded a Pb-osteocalcin dissociation constant of about 2 nM. The 1H NMR spectra showed Pb-induced changes in the same aliphatic and aromatic resonances of osteocalcin that are also affected by Ca(2+)-binding, supporting interaction of Pb2+ at the Ca2+ site. However, the existence of significant differences between the Pb-osteocalcin and Ca-osteocalcin NMR spectra indicates some differences in the structures of the two complexes. Since Pb2+ inhibits the binding of osteocalcin to hydroxyapatite, the high affinity of Pb2+ for osteocalcin would indicate significant inactivation of osteocalcin even at submicromolar free lead levels. Pb(2+)-induced inactivation of osteocalcin could affect bone mineral dynamics and may be related to the observed inverse correlation between blood Pb(2+)-levels and stature and chest circumference observed in growing children.

Animals↗
PubMed1994

Multinuclear NMR studies of intracellular cations in the prehypertensive rat kidney.

We previously reported a significant derangement of intracellular free calcium ion concentration in the isolated perfused kidney of adult spontaneously hypertensive rat (SHR) (J. Biol. Chem. 267, 3637-3643, 1992). In order to investigate whether an abnormality in intracellular free calcium or another ion precedes the development of elevated blood pressure in SHR, we have now compared intracellular free Ca2+, Na+ and pH, using 31P, 19F, and triple quantum-filtered (TQ) 23Na NMR, in perfused kidneys from prehypertensive young SHR and normotensive young Wistar-Kyoto (WKY) rats (5-6 weeks old) which showed no significant difference in blood pressure (B.P. = 120 +/- 5 mmHg and 115 +/- 3 mmHg, for SHR and WKY rats, respectively). Like the adult kidney, no significant differences in intracellular ATP concentration or intracellular pH were found between young prehypertensive SHR and normotensive WKY rat kidneys. The TQ 23Na NMR signal was 47% higher in the SHR kidney, but, due to biological variability and measurement errors, this difference could not be shown to be statistically significant. However, a significant (40%; P < 0.05) increase was found in O2 consumption rate, a measure of the Na+/K(+)-ATPase activity, of the young prehypertensive SHR kidney in comparison to the age-matched WKY rat kidney (7.25 +/- 0.75 for SHR vs. 5.17 +/- 0.18 mumol O2/min g for WKY rat, n = 6). Furthermore, a highly significant (92%; P < 0.02) increase in intracellular free Ca2+ concentration was observed in kidneys from young SHR that had not yet developed high blood pressure in comparison to the kidneys from young normotensive WKY rats (648 +/- 76 nM vs. 339 +/- 39 nM, n = 4), despite the fact that there was no significant difference in blood pressure. Increased intracellular free Ca2+ thus appears to be part of a primary defect, in the prehypertensive young SHR kidney, which may, by way of increased release of arachidonic acid, and subsequent increased production of vasoconstricting arachidonic acid metabolites via the cytochrome P450 pathway, induce elevated blood pressure in the adult SHR.

Adenosine Triphosphate↗
PubMed1994

Diagnosis of umbilical metastasis (Sister Mary Joseph's nodule) by fine-needle aspiration: an immunocytochemical study.

During a ten year period, since we introduced needle aspiration cytology at our institution, we have diagnosed five cases of umbilical metastasis (Sister Mary Joseph's nodule). In none of the cases was any false negative or false positive diagnosis rendered and the primary carcinoma was found below the diaphragm. In all the five cases, cell blocks of the aspirate were subsequently prepared, and highlighted the histologic features of the tumour which corresponded with the cytologic diagnosis. Immunohistochemical staining on the aspirate material in all the cases was considered quite useful in substantiating the cytohistologic diagnosis. Based on our findings, we suggest that fine-needle aspiration cytology as an initial diagnostic procedure in cases suspected of umbilical metastasis should be considered, since it is not only a simple, fast, accurate, and inexpensive diagnostic procedure, but can also save the patient from an invasive surgical procedure, the benefit of which is questionable.

Adenocarcinoma↗
PubMed1994

Comparison of adjuvant activities of aluminium phosphate, calcium phosphate and stearyl tyrosine for tetanus toxoid.

The adjuvant activity of three adjuvants, aluminium phosphate (AIPO4), calcium phosphate (CaHPO4) and stearyl tyrosine for tetanus toxoid (TT) were compared to soluble TT in mice at a dose of 0.5 Lf (1/10th of the single human dose) and in guinea-pigs at a dose of 7.5 Lf (1.5 times the single human dose). Three TT preparations varying in purity were used: (1) ammonium sulphate precipitated formalin detoxified tetanus toxin (AS-TT); (2) AS-TT ultrafiltered to remove low molecular weight peptides (UF-TT): and (3) chromatographically purified tetanus toxin subsequently detoxified with formalin (CP-TT). After primary immunization of mice, AIPO4 absorbed TTs induced higher toxin-neutralizing and IgG (by ELISA) antibodies than CaHPO4, stearyl tyrosine adsorbed or soluble TT preparations, but this difference was no longer present after secondary immunization. TT preparations of varying purities showed similar antibody responses after primary and secondary immunizations when adsorbed on each adjuvant. CP-TT preparation showed the highest neutralizing antibody level amongst soluble preparations after the first dose. All the preparations induced mainly IgG1 antibodies. However, stearyl tyrosine adsorbed TT induced relatively higher IgG2a and IgG2b responses than AIPO4, CaHPO4 adsorbed or soluble TTs particularly after booster injection. No preparation induced detectable IgG3 or IgM antibodies. AIPO4 adsorbed preparations induced higher IgE antibodies than CaHPO4 and stearyl tyrosine adsorbed vaccines. Among the soluble preparations, CP-TT induced lower anti-TT IgE antibodies than standard AS-TT. All these preparations were also tested in the US potency test for adsorbed TT in guinea-pigs. While all the preparations passed this test, AIPO4 adsorbed TT preparations induced higher neutralizing and IgG antibodies than CaHPO4 and stearyl tyrosine adsorbed or soluble TT preparations. In these animal models, purified TT was a strong immunogen and traditional AIPO4 adjuvant gave the highest antibody responses.

Adjuvants, Immunologic↗
PubMed1994

Suitability of the Vero cell method for titration of diphtheria antitoxin in the United States potency test for diphtheria toxoid.

The in vitro Vero cell method for titration of diphtheria antitoxin in immunized guinea pig sera was standardized to obtain comparable results to the in vivo toxin neutralization (TN) test in guinea pigs used to test potency of adsorbed diphtheria toxoid according to the United States Minimum Requirements. In the Vero cell method, the antitoxin titers of the guinea pig sera, obtained 4 weeks after immunization, were markedly dependent on the toxin dose level used in the assay. A toxin dose level termed the Lcd/1 dose (limit of cytopathic dose at 1 IU/ml) for Vero cell method gave comparable estimates of antitoxin activity to the in vivo TN method performed at L+/1 dose of toxin. The Lcd/1 toxin dose level for the Vero cell method is defined as the minimum concentration of diphtheria toxin required to produce a cytopathic effect on Vero cells in 4 days when the solution of diphtheria toxin is mixed with an equal volume of standard diphtheria antitoxin whose concentration is 1 IU/ml. When lower dose levels of toxin were used in the Vero cell assay (Lcd/10 to Lcd/1000), the concentrations of antitoxin in 4 weeks guinea pig sera were 2 to 11.7 times lower than with the Lcd/1 dose level and similarly lower than those measured by the in vivo TN test at L+/1 level. In contrast, the concentration of antitoxin measured in sera from guinea pigs who have been boosted with diphtheria toxoid increased approximately two-fold with the Lcd/1000 dose level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Comparative analysis of tetanus antitoxin titers of sera from immunized mice and guinea pigs determined by toxin neutralization test and enzyme-linked immunosorbent assay.

Enzyme-linked immunosorbent assay (ELISA) and toxin neutralization (TN) test were comparatively evaluated for determination of antibodies to tetanus toxin in sera of immunized guinea pigs and mice at different intervals. Tetanus specific IgG antibodies by ELISA were found in sera of guinea pigs at ninth day after inoculation and in mice sera at seventh day after inoculation when there were no TN antibodies. Two weeks after injection of mice with aluminium phosphate adsorbed tetanus toxoid, anti-tetanus toxin IgG levels determined by ELISA were 35 to 40 times higher than the TN titers. At 4 weeks, ELISA IgG antibody levels of mice and guinea pig sera were still statistically significantly higher than TN titers but with a good correlation between ELISA and TN titers (correlation coefficient of mice sera 0.89). Mice sera at 2 weeks after two doses of tetanus toxoid (interval between doses 30 days) and 8 weeks after a single injection showed similar ELISA and TN titers (P > 0.1). Guinea pig sera at 6 weeks after a single injection showed similar TN and ELISA titers (P > 0.4). During the course of immunization in mice and guinea pigs, low avidity and low affinity IgG antibodies start appearing early which are detected by ELISA but not by TN test. Therefore ELISA results on sera before 6 weeks of immunization determined against a hyper-immune reference serum do not give a true picture of TN levels.

Animals↗
PubMed1994

MR imaging and angiography in tuberculous meningitis.

MRI was performed on 26 patients with tuberculous meningitis, with particular reference to document the cranial nerve abnormalities. MR angiography (MRA) was performed in 20 of the patients. Meningeal enhancement in the basal cisterns or over the convexity of brain was seen in all patients; two show ependymal enhancement. Tuberculomas, single (3), multiple (12) or miliary (2) were detected in 17 patients. Of the 9 patients with cranial nerve palsies, 7 showed contrast enhancement with or without thickening of the involved nerve. Abnormality signal intensity of the involved nerve was seen on proton density and T2-weighted images in one of these patients. MRA revealed focal arterial narrowing in 10 patients, the vessels commonly affected being the terminal segment of the internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. One patient also had a small aneurysm of the proximal middle cerebral artery. Infarcts, haemorrhagic (8) or bland (6), were detected in 14 patients; most were the basal ganglia and internal capsules, large middle or anterior cerebral arterial territory infarcts being seen in only two cases.

Adolescent↗
PubMed1994

MRI in intraspinal tuberculosis.

We studied 20 patients with intraspinal tuberculosis (TB), to characterise the MRI features of tuberculous meningitis and myelitis. MRI leptomeningitis and intramedullary involvement in 11 patients, intramedullary lesions alone in 5, leptomeningitis alone in 2, and isolated extradural disease in 2. TB leptomeningitis was characterised by loculation of the cerebrospinal fluid (CSF), nerve root thickening and clumping (seen only in the lumbar region) or complete obliteration of the subarachnoid space on unenhanced images. Gd-DTPA-enhanced images proved useful in 6 cases, revealing linear enhancement of the surface of the spinal cord and nerve roots or plaque-like enhancement of the dura-arachnoid mater complex. Intramedullary lesions included tuberculomas (8), cord oedema (5) and cavitation (3). In seven cases of intramedullary tuberculoma multiple lesions with skip areas were seen, without significant cord swelling. One patient had an isolated lesion in the conus medullaris. The lesions were iso- or hypointense on T1-weighted images, iso-, hypo- or hyperintense on T2-weighted images and showed rim or nodular enhancement with contrast medium.

Adolescent↗
PubMed1994

Linking radiosilver to monoclonal antibodies reduced by ascorbic acid. Comparison of results with stable silver using gravimetric technique and silver 110-M using radiotracer technique.

Radiosilver-111 and Radiogold-199 were proposed by us (1) as suitable isotopes for radioimmunotherapy in areas such as India by reason of their suitable half-lives and B-emissions (Ag-111 T1/2 = 7.45 d and Au-199 T1/2 = 3.15 d). Since silver is monovalent, it is difficult to link to conventional bifunctional chelates. We therefore explored the use of sulfur-based linkers (2). Encouraged by the Thakur and De Fulvio Technique (3) of linking technetium to disulfide groups in antibodies reduced by ascorbic acid that is eminently biocompatible, we have explored the linkage of silver to immunoglobulin reduced by ascorbic acid. The linkage of silver was assessed with stable Ag-108 using dialysis to quantify the free silver after the reaction of silver and reduced immunoglobulins in various molar ratios (1:1, 1:2, 1:5, 1:10). The silver quantity was estimated gravimetrically after precipitation as chloride. It was observed that using these molar ratios there was negligible silver efflux into the dialysate, suggesting stable linkage. We also assessed the linkage using Ag-110M as radiotracer. The comparative results with the two techniques are described.

Antibodies, Monoclonal↗