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Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 667 records · Page 37Linked to original sources
PubMed1982

Excretion of tumor-associated antigen(s) in the urine of patients with colon carcinoma.

Urine samples collected from patients with colon carcinoma and from normal donors were tested for antigenic activity by the microcomplement-fixation assay. When autologous serum was used as the antibody source, 65.4% (17/26) of the urine samples from patients with colon carcinoma were positive for antigen as opposed to only 10% (2/20) from normal volunteers. Absorption of a representative serum with cultured colon cancer cells completely removed reactivity against its autologous urine. Using this serum to screen urine from colon carcinoma patients, antigenic activity was found in 71.4% (30/46) of the samples; however, only 10% (2/20) of the urine samples from apparently healthy volunteers were positive. Analysis of urine samples collected from three patients before and after resection of their primary colon carcinoma and from nine patients undergoing hyperthermia for liver metastases revealed that two of the patients who had curative surgical procedures had marked decreases in urinary antigen levels by the second postoperative day, while the third patient whose disease was unresectable had no significant decrease. Seven of nine patients with metastatic disease had a greater than fourfold increase in antigen activity after hyperthermia and chemotherapy. These results suggest that tumor-associated antigens were excreted into urine, possibly the result of treatment-caused tumor necrosis. Therefore, assessment of tumor-associated antigen(s) in the urine of patients with colon carcinoma may serve as a marker for response to treatment of this disease.

Adult↗
PubMed1982

Tumour associated antigens in bovine horn cancer.

Tumour associated antigens in bovine horn cancer (HC) were demonstrated by immunodiffusion in agar gel and by immuno-fluorescence. Antiserums raised in rabbits against sonicated pooled horn cancer tissue extracts and absorbed with normal antigens, reacted only with HC extracts on agar gel diffusion. Preparations of normal antigen (skin, horn core epithelium, lymph node and liver) and extracts from other tumours (fibroma, fibrosarcoma and myxoma) did not show any reactivity against absorbed antiserum in this test. The absorbed antiserum showing specific reactivity to HC extracts in gel diffusion tests was conjugated to fluorescein isothiocyanate. Many different HC, normal cells and cells from other tumours were incubated with the conjugate and examined by fluorescent microscopy. HC cells showed specific beaded fluorescence on the surface whereas such fluorescence was not observed in normal cells or cells from other tumours.

Animals↗
PubMed1982

Rosette forming T-lymphocyte levels in the peripheral blood of cattle affected with squamous cell carcinoma of horn.

The level of thymus-derived lymphocytes was assessed by determining the per cent of cells which formed non-immune rosettes with 2-Aminoethyl isothiouronium bromide treated sheep erythrocytes in the peripheral blood of 20 (14 bullocks and 6 cows) histopathologically confirmed cases of bovine squamous cell carcinoma of horn (horn cancer) and an equal number of age-matched control animals. A significantly marked (P less than 0.01) depression in the per cent erythrocyte-rosette forming cell count was observed in horn cancer affected bullocks and cows as compared to the values in unaffected control animals. The decrease in the level of these cells was comparatively more marked in animals which were clinically in advanced stages of the disease.

Animals↗
PubMed1982

Application of cultured human myeloid cells (K562) for detection of immune complexes in human sera.

Cultured human myeloid cells (K562) are known to bear Fc receptors that bind with aggregated human IgG (AHG). These cells were used to develop a radiometric assay for detection and quantitation of immune complexes (IC) in human sera. The binding of AHG or in vitro-formed IC between keyhole lympet hemocyanin (KLH) and human anti-KLH to the K562 cells did not require complement. When the K562 radiometric assay was compared to the complement-consumption assay, the K562 radiometric assay could detect IC over a wider range of antibody:antigen ratios. The incidence and mean IC values detected by the K562 radiometric assay in sera from cancer patients and patients with connective tissue diseases (498 +/- 445 and 436 +/- 209 micrograms AHG equ/ml, respectively) were significantly higher than in sera from healthy volunteers (107 +/- 62 micrograms AHG equ/ml). The IC level among sera from cancer patients ranged from 1-3200 micrograms AHG equ/ml. Studies with a limited number of sera from melanoma and sarcoma patients revealed that the mean IC values were significantly higher in patients who had clinically detectable disease than in those with no evidence of disease. Since the K562 cells do not require complement to interact with AHG, the K562 radiometric assay may be potentially useful for detecting IC in pathologic sera which may or may not contain in vivo-bound complement components.

Antigen-Antibody Complex↗
PubMed1982

Effect of bovine horn cancer serum on E-rosetting capacity of peripheral blood lymphocytes from normal unaffected animals.

The effect of serum from horn cancer affected bullocks and cows on E-rosetting capacity of peripheral blood lymphocytes (PBL) from unaffected control animals was examined. The E-rosette counts were made using 2-aminoethyl isothiouronium bromide (AET) treated sheep red blood cells. A significant decrease in the percentage of EAET rosette forming cells was noticed when PBL were incubated with 50 per cent serum from animals affected with horn cancer. However, no such effect was noticed when PBL were treated with 50 per cent serum from unaffected control animals. A linear relationship was observed between percentage of EAET rosette forming cells of animals affected with horn cancer and E-rosette inhibitory activity of the corresponding serum on PBL from control animals.

Animals↗
PubMed1982

Restoration of E-rosette formation by levamisole and its abrogation by autochthonous serum from cattle with squamous cell carcinoma of horn.

The effect of levamisole on the erythrocyte rosette (E-rosette) forming capacity of peripheral blood lymphocytes from eight horn cancer affected and an equal number of unaffected control animals was studied in vitro. There was an appreciable increase (from 38.75 +/- 2.91 to 56.90 +/- 2.37) in the number of E-rosette forming cells when peripheral blood lymphocytes from horn cancer affected animals were treated with levamisole. However, no significant variation in E-rosette values was noticed when peripheral blood lymphocytes from control animals were treated with this drug. This restorative effect of levamisole on E-rosetting capacity of peripheral blood lymphocytes was abrogated (mean value 39.50 +/- 3.07) when peripheral blood lymphocytes were first treated with levamisole and then incubated in the presence of 50 per cent autochthonous horn cancer serum.

Animals↗
PubMed1982

Demonstration of acid alpha naphthyl acetate esterase activity in bovine lymphocytes and monocytes or macrophages.

Nonspecific acid alpha naphthyl acetate esterase (ANAE) activity has been demonstrated in bovine lymphocytes and monocytes-macrophages. The lymphocytes exhibited a solitary reddish brown globular reaction adjacent to the cell membrane (T-pattern) whereas the monocytes-macrophages revealed a diffuse reddish brown cytoplasmic reaction (M-pattern) product. Cytocentrifuge smears of lymphocytes forming rosettes with sheep erythrocytes also revealed T-pattern ANAE reaction in the majority of the cells. Similar T- and M-patterns of ANAE activity were observed in cryostat sections of biopsies collected from normal bovine lymph nodes and horn cancer tissue sections from bullocks.

Animals↗
PubMed1981

Development of an enzyme immunoassay to detect and quantitate tumor-associated antigens in the urine of sarcoma patients.

This study describes the development of an enzyme immunoassay (EIA) to quantitate antigen in the urine of sarcoma patients and compares its results with those of the authors' previously reported complement fixation assay. Three populations were studied for the presence of urinary antigen by EIA: (1) sarcoma patients who developed metastatic disease after resection of their primary tumor; (2) sarcoma patients who remain clinically disease-free two years after resection of their primary tumor; and (3) normal volunteers with no history of malignant disease. EAch group consisted of nine individuals. None of the urines from normal volunteers and none from sarcoma patients who remained free of disease for two years had elevated antigen titers detectable by EIA. However, all nine patients who developed pulmonary metastatic disease ahd significantly elevated levels of antigen in their urine prior to clinical evidence of disease recurrence. The day-to-day fluctuations in antigen titer detectable by EIA tended to parallel the levels detected by the complement fixation assay. However, EIA detected a significant elevation in antigen titer one to four months earlier than the complement fixation assay in four of the patients in whom disease recurred.

Antigens, Neoplasm↗
PubMed1981

31p nuclear relaxation studies of para- and diamagnetic cobalamins in their two isomeric forms.

A new, naturally occurring isomeric form of vitamin B-12 was reported by us earlier (Katada, M., Tyagi, S., Nath, A., Petersen, R.L. and Gupta, R.K. (1979) Biochim. Biophys. Acta 584, 149-163). The Mössbauer parameters of various derivatives of vitamin B-12, including the one-electron reduced species, cob(II)-alamin (vitamin B-12r), exhibit differences for the two isomeric forms. This and some other observations from our laboratory indicated that the new form (vitamin B-12') presumably constitutes a conformational isomer possessing a different puckering of the corrin ring. The 31P nuclear relaxation studies of vitamins B-12r and B-12'r, B-12 and B-12', and dicyanocobalamin as compared to dicyanocobalamin' reported here are consistent with our earlier conjecture. The relaxation of the 31P nucleus in cob(II)alamins is primarily due to its dipolar interaction with the paramagnetic cobalt and therefore the measurement of the 31P nuclear relaxation times (T1) in the two isomeric forms permits us to calculate Co(II)-31P distances. The Co(II)-31P distance in vitamin B-12'r is found to be larger than that in vitamin B-12r. The 31P T1 value in the diamagnetic cob(III)-alamins is determined predominantly by its dipolar interaction with the two closest protons flanking the phosphate group, one being situated on the ribose moiety and the other on the amino propanol group. The nuclear relaxation times T1 of cyanocobalamin and dicyanocobalamin differ from ;those of their corresponding conformational isomers. The observed differences in 31P relaxation rates of the para- and diamagnetic cobalamins in their two isomeric forms can be understood on the basis of structural changes arising from variations in the nature of puckering of the corrin ring. The 31P chemical shifts in the two isomers remain essentially unchanged, indicating that the structural differences in the isomeric forms do not alter the electronic environment of the phosphorus nucleus.

Isomerism↗
PubMed1981

Improvements in optical methods for measuring rapid changes in membrane potential.

In an effort to increase the utility of optical methods for measuring membrane potential in excitable cells, an additional 369 dyes were tested on giant axons from the squid. Several promising dyes with relatively large absorption and fluorescence signals are described. In addition, a simple modification of the apparatus led to a sixfold increase in the size of dye-related birefringence signals. In preparations with a suitable geometry, these signals are as large as absorption signals but photodynamic damage and bleaching are eliminated when wavelengths longer than the absorption band are used.

Animals↗
PubMed1981

A 1H nuclear relaxation study of the Mn2+ . bleomycin complex. Proximity of the metal to the DNA-binding site.

The antineoplastic action of bleomycin is thought to involve the aerobic degradation of DNA by the Fe2+ . bleomycin complex. Different parts of the bleomycin molecule have been implicated in metal binding and DNA binding. To probe the structure of a metal-containing bleomycin, we studied the effects of the high spin Mn2+ ion in the Mn2+ . bleomycin complex on the longitudinal nuclear relaxation rates of various protons in the molecule. Complexation of Mn2+ to bleomycin was also studied by EPR, and a Scatchard plot of the EPR data revealed a single tight divalent cation-binding site per molecule. From the magnitudes of the paramagnetic effects of Mn2+ on the nuclear relaxation rates of several assigned resonances, we calculate the relative distances of the corresponding protons from the metal. Using a pyrimidine methyl to metal distance of 6.5 A, consistent with the metal coordination of this aromatic group of bleomycin established on the basis of other studies, we find from our data that the bithiazole and COOH-terminal portions of the molecule are located spatially very close to the metal. These groups have previously been implicated in DNA binding. Our metal to bithiazole proton distances (approximately 5.4 A) are consistent with bithiazole as a metal ligand, although possible involvement of interactions other than direct coordination in maintaining close proximity cannot be excluded. Our distance data also argue against the imidazole ring of beta-hydroxyhistidine as a ligand. The short distance between the metal- and DNA-binding sites indicated by our studies would help ensure that the reactive reduced oxygen radicals produced at the metal site during Fe2+ oxidation in the aerobic Fe2+ . bleomycin complex reach the substrate DNA before the destruction of these radicals can occur in other ways.

Bleomycin↗