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Biomedical subjects

S K Aggarwal

Publications and source records attributed to S K Aggarwal.

104 records · Page 6Linked to original sources
PubMedDate not supplied

Mercury determination in blood by gas chromatography-mass spectrometry.

A stable isotope dilution gas chromatography-mass spectrometry method using 196Hg as an internal standard is described for determining Hg in blood. In this method, the blood samples are not subjected to any digestion to avoid the loss of Hg. A solution of 0.6M HCl is used to free Hg present in blood from proteins. The pH of the solution is adjusted to 9 using borate buffer and Hg chelated using lithium bis(trifluoroethyl)dithiocarbamate. All isotope ratio measurements are made using an organic mass spectrometer. Overall precision values for the five major Hg isotopes relative to 202Hg are 1.6-2.3% when 10 ng samples of chelated Hg are analyzed. No appreciable memory or carryover effect is observed when two synthetic mixtures differing in 196Hg/202Hg ratios by a factor of 30 are sequentially analyzed. The method is validated by determining Hg in blood samples using isotope dilution GC-MS.

Calibration↗
PubMedDate not supplied

Isotope dilution gas chromatography/mass spectrometry for cadmium determination in urine.

A stable isotope dilution gas chromatographic/mass spectrometric method using 106Cd as an internal standard is described for determining Cd in urine. In this method, the urine matrix is digested with HNO3 + H2O2 and the Cd is chelated with lithium bis(trifluoroethyl)dithiocarbamate. All isotope ratio measurements are made with an organic mass spectrometer. Overall precision values for the five major isotopes relative to 114Cd are 1 to 3% when 10-ng samples of chelated Cd are analyzed. Accuracy of the method is established by measuring Cd in the NIST freeze-dried urine reference material. A small memory effect is observed when measuring isotope ratios differing by a factor of 10. This can, however, be minimized by optimum addition of the internal standard solution.

Cadmium↗
PubMedDate not supplied

Histochemical and morphological identification of Kupffer cells activated by cisplatin.

Cisplatin is a potent anti-cancer agent which has been shown to activate Kupffer cells. These activated macrophages demonstrate an increase in extensions, lysosomes, and peroxisomes increasing their anti-tumor activity. Wistar rats were treated with cisplatin (9 mg/kg) and sections of liver were excised for light and electron microscopic analysis at 1, 6, 15, and thirty days post treatment. Non-specific esterase staining was used to differentiate Kupffer cells using light microscopy, morphologic criteria were used for TEM analysis. Liver sections taken 6 days post treatment showed the greatest number of activated macrophages, with the highest degree of activation. Interaction between natural killer cells and Kupffer cells was only seen 6 days post treatment. These results show that cisplatin's ability to enhance the immune system requires several days post treatment to reach maximum potency.

Animals↗
PubMedDate not supplied

Immune system activation by CDDP and "poly-plat".

Murine peritoneal macrophages, human fibroblasts and human ovarian teratocarcinoma cells were treated with CDDP (10 micrograms/ml) and "poly-plat" (10 micrograms/ml) for 2 h and cultured for 2-96 h. After "poly-plat" treatment macrophages developed cytoplasmic extensions much faster and secreted higher levels of interleukin-2 (IL-2), compared to CDDP. "Poly-plat" treated human fibroblasts demonstrated a significant release of IL-2 (138 pg/ml), compared to CDDP (64 pg/ml) or the untreated normal cells (31 pg/ml) after 8 h. Correspondingly there was a 53% increase in cells after "poly-plat" treatment compared to only 37% after CDDP. However, human ovarian teratocarcinoma cells didn't show any significant increase in IL-2 levels after "poly-plat" treatment and there was instead a decrease of 15% in cell numbers at 8 h. Based on our studies, we propose that "poly-plat" is more effective in activation of the macrophages and human fibroblasts in terms of IL-2, but not so with human ovarian teratocarcinoma cells.

Adjuvants, Immunologic↗
PubMedDate not supplied

Fine needle aspiration cytologic diagnosis of the solitary cold thyroid nodule. Comparison with ultrasonography, radionuclide perfusion study and xeroradiography.

Thirty-six cases of solitary and scintigraphically "cold" thyroid nodules were studied by fine needle aspiration (FNA) cytology, ultrasonography, radionuclide perfusion study (RPS) and xeroradiography with the aim of differentiating the neoplastic from the nonneoplastic nodules. Histologic study of the excised specimens provided the definitive diagnosis in all cases. Of the techniques used in this study, FNA cytology and RPS had the highest sensitivities and specificities. Ultrasonography and xeroradiography were of limited use due to their low sensitivity rates.

Adenocarcinoma↗
PubMedDate not supplied

Electrocardiographic changes in multi bacillary leprosy.

14 cases of multi bacillary leprosy (BL and LL) were investigated biochemically and ECG recording was done. Serum cholesterol was found to be raised in 4 out of 14 cases and SGOT was raised in 2 cases. P wave, PR interval and QRS complex did not show any changes, ST segment was depressed in 2 cases, T wave was flat in 2 cases and inverted in one case and Q-Tc interval was prolonged (more than 0.40 secs) in 3 cases.

Adult↗
PubMedDate not supplied

Age and intrinsic left ventricular myocardial contractility.

The purpose of this study was to compare the left ventricular (LV) intrinsic contractile function in normal elderly (age > or = 60 years, mean age 66 +/- 4 years) and young (age < or = 35 years, mean 27 +/- 9 years) healthy volunteers by stress-shortening and stress-length relationship using a co-variate analysis. Echocardiographically determined meridional and circumferential wall stress were plotted against LV fractional shortening, velocity of circumferential fibre shortening, end-systolic volume and diameter. LV ejection fraction, preload (denoted by end-diastolic volume) and afterload (expressed as circumferential wall stress) were similar in the two groups. Stress-shortening and stress-length relationships using the circumferential wall stress showed no difference in the two groups, although meridional wall stress was greater in the elderly population. Our results suggest that circumferential wall stress is a better method to detect intrinsic contractile abnormality in the elderly. Intrinsic LV ejection performance is within the normal range in the elderly healthy individuals.

Adult↗
PubMedDate not supplied

Enhanced immune system activation after treatment with novel antineoplastic platinum agents.

"Poly-plat", SSP, and SAP are second generation analogs of cisplatin (CDDP) with higher efficacy and potency. In order to understand the mechanism of action of these compounds, isolated murine peritoneal macrophages were treated with "poly-plat", SSP, or SAP (5 micrograms/ml) for 2 h. Treated macrophages demonstrated an increase in the number of lysosomes, but only "poly-plat" and SSP treated macrophages were stimulated to form the cytoplasmic extensions so very characteristic of cisplatin after 2 h and 24 h post-treatment. SAP showed cytoplasmic extensions only after 24 h post-treatment, and demonstrated a back to the normal discoid form when viewed at 24 h post-treatment. When drug treated macrophages were co-incubated with S180 tumor cells, cytoplasmic extensions of the macrophages developed contacts, and cytoplasmic continuity with the tumor cells, and a subsequent transfer of lysosomes from macrophage to tumor cell was observed after only 2 h of co-incubation. After 24 h of co-incubation, lysis of S180 cells was achieved. Analysis of the tissue culture supernatants collected from "poly-plat", SSP, and SAP treated macrophages demonstrated the enhanced activity of interleukin-1 alpha of over 400 pg/ml after 2 h post-treatment, compared to only 300 pg/ml with cisplatin 24 h post-treatment. However, only SSP demonstrated an increase in TNF-alpha activity (2000 pg/ml) after 2 h post-treatment, which is comparable to that of cisplatin. Based on our observations we propose that "poly-plat", SSP, and SAP activate various cytolytic factors of the immune system better, than cisplatin.

Animals↗