301
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Mahajan M, Agarwal DS, Gadre DJ, Singh NP, Gupta HC, Talwar V. Initial and acquired drug resistance of Mycobacterium tuberculosis in east Delhi. THE JOURNAL OF COMMUNICABLE DISEASES 1996; 28:15-9. [PMID: 8778175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
One hundred and fifty six strains of Mycobacterium tuberculosis, isolated from cases of pulmonary tuberculosis were subjected to sensitivity test to detect initial and acquired drug resistance to Streptomycin, isoniazid, Rifampicin, Ethambutol and Pyrazinamide. Initial and acquired drug resistance was observed to one or more drugs in 16% and 24.4% of the patients respectively. Strains resistant to Rifampicin and Ethambutol were resistant to Isoniazid also. Drug resistance was unrelated to age and sex of the patients.
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302
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Agarwal AK, Zamzachin G, Singh MY, Singh NP. Aids related kaposi's sarcoma - Like lesion. Indian J Dermatol Venereol Leprol 1996; 62:129-131. [PMID: 20948008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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303
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Singh NP, Eardley I. An uncommon complication of urethral catheterization. BRITISH JOURNAL OF UROLOGY 1996; 77:316-7. [PMID: 8800911 DOI: 10.1046/j.1464-410x.1996.91532.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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304
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Lai H, Singh NP. Reply to “Comment on ‘Acute low-intensity microwave exposure increases DNA single-strand breaks in rat brain cells’”. Bioelectromagnetics 1996. [DOI: 10.1002/(sici)1521-186x(1996)17:2<166::aid-bem13>3.0.co;2-q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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305
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Abstract
Male Sprague-Dawley rats were intubated with 4 g/kg body weight of ethanol (in a 20%, v/v, water solution). Brain cells were analyzed for single-strand DNA breaks at various post-ethanol administration time points using an alkaline microgel electrophoresis assay. Results showed a significant increase in single-strand DNA breaks in brain cells that peaked at approx. 4 h and returned to control level within 6 h after ethanol administration.
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306
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Moore JC, Lai H, Li JR, Ren RL, McDougall JA, Singh NP, Chou CK. Oral administration of dihydroartemisinin and ferrous sulfate retarded implanted fibrosarcoma growth in the rat. Cancer Lett 1995; 98:83-7. [PMID: 8529210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the presence of iron, dihydroartemisinin forms free radicals and causes cell death. Since most cancer cells have high rates of iron intake, dihydroartemisinin would have selective cytotoxic effect on cancer cells. The present experiment was designed to study the effect of dihydroartemisinin and ferrous sulfate on the growth of implanted fibrosarcoma in the rat. We found that the growth rate of the tumor was significantly retarded by daily oral administration of ferrous sulfate followed by dihydroartemisinin. No significant tumor growth retardation effect was observed in rats treated with either dihydroartemisinin or ferrous sulfate alone. The drug treatment did not significantly affect body weight compared with untreated tumor-implanted animals and no apparent toxic effect was observed after drug treatment. An artemisinin analog-ferrous salt combination may provide a novel approach for cancer therapy.
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307
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Moore JC, Lai H, Li JR, Ren RL, McDougall JA, Singh NP, Chou CK. Oral administration of dihydroartemisinin and ferrous sulfate retarded implanted fibrosarcoma growth in the rat. Cancer Lett 1995. [DOI: 10.1016/s0304-3835(06)80014-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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308
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Singh NP, Graham MM, Singh V, Khan A. Induction of DNA single-strand breaks in human lymphocytes by low doses of gamma-rays. Int J Radiat Biol 1995; 68:563-9. [PMID: 7490506 DOI: 10.1080/09553009514551551] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We hypothesized that very low doses of gamma-rays have a genotoxic effect as measured by DNA single-strand breaks (ssbs). To test our hypothesis we used a newly developed alkaline microgel electrophoretic technique to quantitate DNA ssbs in freshly isolated human lymphocytes. An enhanced sensitivity to detect low levels of DNA damage was made possible by this method due to an additional step of DNA precipitation by ethanol in agarose microgels. We exposed lymphocytes from three subjects for 1 h at 4 degrees C to 740 MBq of technetium 99-m at a distance of 20 cm (0.25 mGy), 10 cm (1.02 mGy), and 5 cm (4.08 mGy) from the source vial. Doses of 1.02 and 4.08 mGy induced a significant dose-dependent increase in DNA ssbs in human lymphocytes from three subjects, each examined on three different days.
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309
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Singh NP, Mittal SR, Mittal B. Significance of subxiphoid (high epigastric) pulsation in patients with acute myocardial infarction. Int J Cardiol 1995; 51:306-7. [PMID: 8586481 DOI: 10.1016/0167-5273(95)02425-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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310
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Dutta TK, Hamide A, Singh NP, Ramesh J. Mononeuropathy multiplex cranialis in a case of non-Hodgkin's lymphoma mistaken as paraneoplastic syndrome. JOURNAL OF THE INDIAN MEDICAL ASSOCIATION 1995; 93:396. [PMID: 9053419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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311
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Mittal SR, Singh NP, Garg S. Cardiac pulsations in patients with isolated right ventricular infarction. Int J Cardiol 1995; 51:103-4. [PMID: 8522392 DOI: 10.1016/0167-5273(95)02373-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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312
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Abstract
We evaluated the DNA damaging effects of ethanol and its major metabolite, acetaldehyde. Freshly isolated human lymphocytes from two healthy donors were incubated with 0, 1.56, 6.25, 25, and 100 mM of ethanol or acetaldehyde in complete medium for 1 h. We used a newly developed, sensitive, alkaline microgel electrophoresis technique to quantitate single- and double-strand DNA breaks or alkali-labile sites in individual cells. Ethanol did not induce DNA strand breaks. However, acetaldehyde induced both single-strand (even at the lowest concentration of 1.56 mM) and double-strand breaks (only at the highest concentration of 100 mM). Following exposure to acetaldehyde, cells were incubated in complete medium for 30, 60, and 120 min. During this incubation period, most cells were unable to repair DNA single- and double-strand breaks caused by acetaldehyde. We also observed a significant cell loss after exposure to acetaldehyde. To our knowledge, this is the first study demonstrating DNA single- and double-strand breaks by acetaldehyde.
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313
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Mittal SR, Mittal B, Singh NP. Exercise-induced myocardial ischemia in young patients of rheumatic mitral stenosis. Int J Cardiol 1995; 50:198. [PMID: 7591334 DOI: 10.1016/0167-5273(95)02354-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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314
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Khan A, Lai H, Nishimura Y, Mirolo MH, Singh NP. Effects of ECS on DNA single-strand breaks in rat brain cells. CONVULSIVE THERAPY 1995; 11:114-21. [PMID: 7552050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We conducted a series of experiments to evaluate possible molecular mechanisms by which electroconvulsive therapy, a commonly used treatment for depression, may exert its adverse effects such as amnesia. We assessed the effects of repeated electroconvulsive shocks (ECS) alone and in combination with low-level radiograph irradiation on DNA single-strand breaks in cells in the rat brain, using a sensitive alkaline microgel electrophoresis assay method. Our results show that ECS, when administered alone, had no significant effects on DNA single-strand breaks in cells in either the hippocampus or the rest of the brain. However, repeated ECS when combined with a low-level radiograph irradiation produced a small but significant increase in DNA single-strand breaks in rat brain cells.
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315
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Lai H, Singh NP. Selective cancer cell cytotoxicity from exposure to dihydroartemisinin and holotransferrin. Cancer Lett 1995; 91:41-6. [PMID: 7750093 DOI: 10.1016/0304-3835(94)03716-v] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rapid cell death, as evidenced by a decrease in cell counts, was observed when molt-4-lymphoblastoid cells, a human leukemia cell line, were exposed to holotransferrin (12 microM) and dihydroartemisinin (1-200 microM). Incubation with either compound alone was significantly less effective. Significantly less cell death was observed when normal human lymphocytes were exposed to a combination of these 2 drugs. Probit analysis of dose-response functions shows that the drug combination is approximately 100 times more effective on molt-4 cells than lymphocytes (LD50s for molt-4 and lymphocytes were 2.59 microM and 230 microM, respectively). This drug combination may provide a novel approach for cancer treatment.
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316
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Rohatgi A, Singh NP. The idiopathic hypereosinophilic syndrome. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1995; 43:207-10. [PMID: 11256911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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317
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Lai H, Singh NP. Acute low-intensity microwave exposure increases DNA single-strand breaks in rat brain cells. Bioelectromagnetics 1995; 16:207-10. [PMID: 7677797 DOI: 10.1002/bem.2250160309] [Citation(s) in RCA: 226] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Levels of DNA single-strand break were assayed in brain cells from rats acutely exposed to low-intensity 2450 MHz microwaves using an alkaline microgel electrophoresis method. Immediately after 2 h of exposure to pulsed (2 microseconds width, 500 pulses/s) microwaves, no significant effect was observed, whereas a dose rate-dependent [0.6 and 1.2 W/kg whole body specific absorption rate (SAR)] increase in DNA single-strand breaks was found in brain cells of rats at 4 h postexposure. Furthermore, in rats exposed for 2 h to continuous-wave 2450 MHz microwaves (SAR 1.2 W/kg), increases in brain cell DNA single-strand breaks were observed immediately as well as at 4 h postexposure.
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318
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Singh NP, Stephens RE, Schneider EL. Modifications of alkaline microgel electrophoresis for sensitive detection of DNA damage. Int J Radiat Biol 1994; 66:23-8. [PMID: 8027608 DOI: 10.1080/09553009414550911] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The alkaline microgel electrophoresis technique was modified to achieve a substantial increase in sensitivity for the detection of radiation-induced DNA damage in human lymphocytes. This increased sensitivity was achieved through: (1) the addition of free radical scavengers to the electrophoresis solution to reduce DNA damage generated during alkaline unwinding and electrophoresis; (2) the modification of the electrophoresis unit to achieve a more uniform electric field; (3) the use of YOYO-1, a DNA dye, producing fluorescence 500-fold more intense than ethidium bromide; and (4) the introduction of an image analysis system for the quantitation of DNA migration. In addition to increasing sensitivity, these modifications have increased the speed with which observations can be quantified, and improved reproducibility from experiment to experiment. In human lymphocytes, these modifications have resulted in an increased sensitivity of several fold, allowing the detection of DNA damage in the range of 50 mGy. This increased sensitivity for the detection of DNA damage should extend the utility of this technique.
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319
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Singh NP, Pillai D, Kar C, Sridharan M, Das AK. Nephrotic syndrome in a HIV seropositive patient. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1994; 42:500. [PMID: 7852241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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320
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Singh J, Khare S, Prasad AK, Garg A, Singh NP, Sharma RS. An outbreak of influenza A (H3N2) in Delhi, 1993. THE JOURNAL OF COMMUNICABLE DISEASES 1994; 26:14-8. [PMID: 7963377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An outbreak of Influenza A, subtype H3N2 occurred in Delhi during July-August, 1993. Both urban and rural areas were affected. Attack rates in children and adults were found to be similar; the mean age of patients from whom the virus was isolated was found to be 21 years. The disease was of acute onset, mild in nature and about one week in duration. Main symptoms included fever, chills, cough, sore throat, bodyaches, backache and headache. Complications were absent. About 82 per cent of the affected house-holds had only a single case. Influenza A subtype H3N2 virus was isolated from 12 of 15 throat swabs collected from PUO cases.
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321
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Bernstein ML, Despars JA, Singh NP, Avalos K, Stansbury DW, Light RW. Reanalysis of the 12-minute walk in patients with chronic obstructive pulmonary disease. Chest 1994; 105:163-7. [PMID: 8275726 DOI: 10.1378/chest.105.1.163] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The purpose of this study was to determine the correlation between different intervals in the 12-min walk test, to determine which of the intervals best correlated with maximal oxygen intake (VO2max) and maximal CO2 expelled (VCO2max) and to determine the degree of correlation between changes in the VO2max and changes in the walk test and spirometry. Nine elderly (age, 67 +/- 4 years) patients with moderate COPD (FEV1, 1.32 +/- 0.28 L) who were ventilatory limited were seen 6 times over a 14-week period. At each visit they performed spirometry, a 12-min walk, and a symptom-limited maximal exercise test. During the 12-min walk the distances traversed in each 2-min interval were recorded. A Borg score was obtained at the end of each 2 min. The distances that the patients walked in each 2-min interval were very similar, but the mean Borg score became higher the longer the patient walked. The Borg score after 2 min was 1.64 +/- 1.15, while the Borg score after 12 min was 5.70 +/- 3.59. The correlation coefficients between the distance walked at various intervals and the oxygen consumption (VO2)/kg (approximately 0.65) and the VCO2/kg (approximately 0.52) were very similar. However, changes in the VO2/kg were more closely correlated with changes in the 12-min walk (r = 0.72), than with changes in the 6-min walk (r = 0.64), the 4-min walk (r = 0.59), or the 2-min walk (r = 0.53). This latter observation suggests that the 12-min walk may be preferable to tests in which the patient walks 4 or 6 min for documenting changes in the exercise capabilities.
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322
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323
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Singh NP, Samal SC, Kar CR, Ratnakar C, Das AK. Primary extranodal non-Hodgkins lymphoma of the palate. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1993; 41:465-6. [PMID: 8300501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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324
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Anand KS, Mittal S, Singh NP. Carpal tunnel syndrome with propranolol. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1993; 41:313. [PMID: 8300472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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325
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Singh NP, Despars JA, Stansbury DW, Avalos K, Light RW. Effects of buspirone on anxiety levels and exercise tolerance in patients with chronic airflow obstruction and mild anxiety. Chest 1993; 103:800-4. [PMID: 8449072 DOI: 10.1378/chest.103.3.800] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The objective of this study was to determine if buspirone would alleviate anxiety and improve exercise tolerance of anxious patients with chronic airflow obstruction (CAO). Eleven male patients with mild to moderate anxiety and CAO completed this study comparing buspirone, 10 to 20 mg given three times a day, with placebo. Patients were evaluated with State Trait Anxiety Inventory, spirometry, 12-min walk, incremental exercise on a cycle ergometer to symptom limitation and measurement of dyspnea with a modified Borg scale at exercise levels and the end of each 2 min on 12-min walk. There were no significant differences in anxiety scores, work load, maximum oxygen consumption per minute, maximum expired volume per minute, PETCO2, PETO2, 12-min walking distance or dyspnea scores after 6 weeks of buspirone or placebo therapy. We conclude that administration of buspirone has no significant effect on anxiety levels, exercise capabilities or PETO2 or PETCO2 in patients with CAO and mild anxiety.
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326
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Singh NP, Vargas FS, Cukier A, Terra-Filho M, Teixeira LR, Light RW. Arterial blood gases after coronary artery bypass surgery. Chest 1992; 102:1337-41. [PMID: 1424847 DOI: 10.1378/chest.102.5.1337] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Coronary artery bypass graft (CABG) surgery adversely affects arterial blood gas (ABG) determinations. The purposes of this study were to assess serial changes in ABGs following bypass surgery and identify factors that may influence these changes. Room air ABGs were obtained preoperatively and on days 1, 2, 4, 6, and 8 postoperatively on 125 patients undergoing bypass surgery. Fifty-five patients (saphenous vein grafting [SVG] group) had only SVG grafting while 70 (internal mammary artery [IMA] group) received one (60 patients) or two (10 patients) IMA grafts in addition to the SVG grafts and were subjected to pleurotomy. The mean preoperative values (+/- SD) were as follows: PaO2, 75.1 +/- 7.7 mm Hg, P(A-a)O2, 20.9 +/- 7.5 mm Hg; PaCO2, 33.6 +/- 4.1 mm Hg; pH, 7.43 +/- 0.04; hemoglobin, 14.8 +/- 1.4 g/dl; and hematocrit, 44.2 +/- 3.9 percent. There was a large decrease in the PaO2 postoperatively. The nadir for the PaO2 (55.7 +/- 6.6 mm Hg) occurred on the second postoperative day. Eight days postoperatively, there were still significant abnormalities; the PaO2 was 65.7 +/- 7.3 mm Hg, the P(A-a)O2 was 33.2 +/- 8.8 mm Hg; the hemoglobin was 10.5 +/- 1.4 g/dl; and the hematocrit was 31.7 +/- 4.0 percent. The decrease in the PaO2 was particularly noteworthy given the large decrease in the hemoglobin and hematocrit. The changes in the PaO2 were not significantly correlated with the age, number of grafts, pump time, length of anesthesia, or endotracheal intubation or smoking history. Immediately postoperatively, changes were similar in both groups (p > 0.05); on the second postoperative day, the PaO2 had decreased 26.9 percent in the SVG group and 25.5 percent in the IMA group. However, the postoperative abnormalities resolved more slowly in the IMA group (p < 0.05). These observations suggest that the additional trauma to the lungs and chest wall in the IMA group (pleurotomy, the placing of pleural drains, etc) will result in a longer recovery time in the IMA group than in SVG group.
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327
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Chauhan RS, Singh NP. Cell-mediated immune response in rotavirus-infected calves: leucocyte migration inhibition assay. J Comp Pathol 1992; 107:115-8. [PMID: 1430345 DOI: 10.1016/0021-9975(92)90101-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The cell-mediated immune (CMI) response was determined in rotavirus-infected calves by leucocyte migration inhibition assay with blood, spleen, mesenteric lymph node and intestinal lymphocytes. The inhibition of migration was more prominent in intestinal and mesenteric lymph node lymphocytes than in spleen and blood. In rotavirus-infected calves, the assay indicated the presence of CMI response which was more prominent at the local site of infection.
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328
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Chauhan RS, Singh NP. Rapid diagnosis of rotavirus infection in calves by dot immunobinding assay. Vet Rec 1992; 130:381. [PMID: 1318598 DOI: 10.1136/vr.130.17.381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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329
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Ghose S, Singh NP, Kaur D, Verma IC. Microphthalmos and anterior segment dysgenesis in a family. OPHTHALMIC PAEDIATRICS AND GENETICS 1991; 12:177-82. [PMID: 1815168 DOI: 10.3109/13816819109025814] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An unusual sibship is described of a spectrum of microphthalmos associated with various degrees of anterior segment mesodermal dysgenesis ranging from partial sclerocornea to congenital anterior staphyloma. The possible embryologic significance of these anomalies manifesting together are discussed, along with the visual benefits which are sometimes surprisingly attainable in these usually hopeless eyes.
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330
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Singh NP, Tice RR, Stephens RE, Schneider EL. A microgel electrophoresis technique for the direct quantitation of DNA damage and repair in individual fibroblasts cultured on microscope slides. Mutat Res 1991; 252:289-96. [PMID: 2052008 DOI: 10.1016/0165-1161(91)90008-v] [Citation(s) in RCA: 194] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We demonstrate by single-cell microgel electrophoresis that the 2 main techniques, trypsinization and scraping, used to collect normal diploid mammalian cells cultured in monolayer induce DNA damage. To minimize this potential interference with studies on DNA damage and repair, we have standardized the single-cell gel electrophoretic (SCG) technique for the in situ quantitation of DNA single-strand breaks and alkali-labile sites in cultured human-fibroblasts. To demonstrate the utility of this technique, human neonatal foreskin-derived fibroblasts were allowed to attach to frosted microscope slides and then either irradiated with X-rays (25-200 rad) or treated for 1 h with hydrogen peroxide (2.2-140.8 mumoles). Treatment with either agent induced a dose-dependent increase in DNA migration. At equal levels of DNA damage, cell-to-cell variability in DNA migration was more heterogeneous for hydrogen peroxide-treated cells than for X-irradiated cells. A time course study to evaluate the kinetics of DNA repair for X-ray (200 rad)-induced damage indicated that the damage was completely repaired within 2 h. Applications of this technique for in vitro toxicology are discussed.
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331
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Singh NP, Danner DB, Tice RR, Pearson JD, Brant LJ, Morrell CH, Schneider EL. Basal DNA damage in individual human lymphocytes with age. Mutat Res 1991; 256:1-6. [PMID: 1944382 DOI: 10.1016/0921-8734(91)90026-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A role for DNA damage is central to many theories of aging, but attempts to show an increase in DNA damage with age have yielded contradictory results. However, previous experiments have been of limited sensitivity, only able to examine induced (not basal) damage or pooled (not individual) cells. In this report, we apply a novel technique (Singh et al., 1988) to directly measure basal levels of DNA single-strand breaks and alkali-labile sites in individual human peripheral blood lymphocytes (PBL) obtained from young (less than 60 years) and old (more than 60 years) male donors. This approach shows that while average changes with age are small, changes in certain individuals and in certain cells may be large: the mean increase in damage was only 12%, but the increase in a subpopulation of highly damaged lymphocytes was 5-fold. However, most of this increase was contributed by just 3 of 17 older subjects. Further characterization of these individuals may shed light on the relationship between DNA damage and aging.
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332
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Tice RR, Andrews PW, Hirai O, Singh NP. The single cell gel (SCG) assay: an electrophoretic technique for the detection of DNA damage in individual cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 283:157-64. [PMID: 2068983 DOI: 10.1007/978-1-4684-5877-0_17] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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333
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Singh NP, Prakash SK, Rani S, Jain SK, Kumar V. Acquired pure red cell aplasia without thymoma. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1990; 38:593-4. [PMID: 2123184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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334
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Singh NP, Danner DB, Tice RR, Brant L, Schneider EL. DNA damage and repair with age in individual human lymphocytes. Mutat Res 1990; 237:123-30. [PMID: 2233818 DOI: 10.1016/0921-8734(90)90018-m] [Citation(s) in RCA: 146] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Previous biochemical studies on DNA repair competence and aging have been limited to techniques, such as alkaline elution or nucleoid sedimentation, involving mass cell populations. These techniques provide no information about the distribution of DNA damage and repair among individual cells and are unlikely to detect age-dependent changes affecting a minor fraction of the cell population. We have recently described a microgel electrophoretic assay (Singh et al., 1988) that measures, at the level of the individual cell, single-strand DNA breaks and alkali-sensitive sites. Here, we employ this method to analyze DNA damage and repair in lymphocytes isolated from the peripheral blood of 31 subjects (23 males and 8 females aged 25-91 years) and exposed in vitro to 200 rads of X-irradiation. While basal (pre-irradiation) levels of damage were independent of the age of the donor, an age-dependent increase in DNA damage was observed immediately following irradiation. For all subjects, the mean level of DNA damage was restored to pre-irradiation control levels within 2 h of incubation at 37 degrees C. However, a distribution analysis of DNA damage among cells within each sample indicated the presence of a few highly damaged cells (4-16%) in the 2-h sample, the occurrence of which was significantly more common among aged individuals. These data indicate an age-related decline in DNA repair competence among a small subpopulation of lymphocytes.
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335
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Abstract
The behaviour of thorium in animals exposed through injection, ingestion and inhalation, as well as in uranium miners, millers and the general population suggests that thorium accumulates primarily in the lung, tracheobronchial lymph nodes and skeleton; or in the liver if injected with polymeric thorium. Epidemiological studies on uranium miners, Thorotrast studies in man and animal, and studies on the toxic effects of thorium in animals suggest that there is no apparent heart diseases due to exposure to thorium in man and animal.
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336
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Singh NP, Danner DB, Tice RR, McCoy MT, Collins GD, Schneider EL. Abundant alkali-sensitive sites in DNA of human and mouse sperm. Exp Cell Res 1989; 184:461-70. [PMID: 2806399 DOI: 10.1016/0014-4827(89)90344-3] [Citation(s) in RCA: 186] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The DNA of human and mouse sperm cells was analyzed by single-cell microgel electrophoresis, by agarose gel electrophoresis, and by alkaline elution--three techniques that can detect single-strand DNA breaks and/or labile sites. Under these conditions a surprisingly large number of single-strand DNA breaks, approximately 10(6) to 10(7) per genome, were detected in human and mouse sperm but not in human lymphocytes or in mouse bone marrow cells. These breaks were also present in chicken erythrocyte DNA, which is also highly condensed. These breaks were not observed under neutral pH conditions nor under denaturing conditions not involving alkali, suggesting that these sites are alkali-sensitive and do not represent preexisting single-strand breaks. The high frequency of such sites in sperm from healthy mouse and human donors suggests that they represent a functional characteristic of condensed chromatin rather than DNA damage.
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337
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Hira HS, Singh NP, Gondal R, Sethi KK, Prakash SK. Primary fibrosarcoma of heart. THE INDIAN JOURNAL OF CHEST DISEASES & ALLIED SCIENCES 1989; 31:207-9. [PMID: 2638657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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338
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Ahuja RK, Prakash SK, Singh NP, Kapoor R, Saha MM. Multiple aneurysms in Marfan's syndrome. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1989; 37:414-5. [PMID: 2592340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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339
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Ajmani A, Prakash SK, Rattanavalli E, Jain SK, Singh NP. Acute leukemia in a diabetic. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1988; 36:461. [PMID: 3204099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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340
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Saha SK, Singh NP, Sanyal SC. Enterotoxigenicity of chicken isolates of Campylobacter jejuni in ligated ileal loops of rats. J Med Microbiol 1988; 26:87-91. [PMID: 3385766 DOI: 10.1099/00222615-26-2-87] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ligated ileal loops in rats of the Charles-Foster strain, weighing 200-250 g and aged 7-8 months, provided a sensitive and reproducible means of testing the enterotoxigenicity of Campylobacter jejuni. All of 16 chicken isolates caused fluid accumulation comparable to that produced by toxigenic Vibrio cholerae O1, strain 569B. However, 11 of the isolates required one to three consecutive passages through the rat gut before doing so. The amount of fluid produced increased after each passage. Of three culture media tested, brucella broth of pH 6.7 supported the highest degree of enterotoxigenesis. Filtrates of cultures of all 16 chicken isolates in this medium were as effective as viable C. jejuni in producing fluid in ileal loops. The enterotoxin was neutralised completely by cholera antitoxin diluted 1 in 160, indicating its close immunobiological relationship to cholera toxin.
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341
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Singh NP, McCoy MT, Tice RR, Schneider EL. A simple technique for quantitation of low levels of DNA damage in individual cells. Exp Cell Res 1988; 175:184-91. [PMID: 3345800 DOI: 10.1016/0014-4827(88)90265-0] [Citation(s) in RCA: 7300] [Impact Index Per Article: 202.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Human lymphocytes were either exposed to X-irradiation (25 to 200 rads) or treated with H2O2 (9.1 to 291 microM) at 4 degrees C and the extent of DNA migration was measured using a single-cell microgel electrophoresis technique under alkaline conditions. Both agents induced a significant increase in DNA migration, beginning at the lowest dose evaluated. Migration patterns were relatively homogeneous among cells exposed to X-rays but heterogeneous among cells treated with H2O2. An analysis of repair kinetics following exposure to 200 rads X-rays was conducted with lymphocytes obtained from three individuals. The bulk of the DNA repair occurred within the first 15 min, while all of the repair was essentially complete by 120 min after exposure. However, some cells demonstrated no repair during this incubation period while other cells demonstrated DNA migration patterns indicative of more damage than that induced by the initial irradiation with X-rays. This technique appears to be sensitive and useful for detecting damage and repair in single cells.
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342
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Siegrist T, Schneemeyer LF, Waszczak JV, Singh NP, Opila RL, Batlogg B, Rupp LW, Murphy DW. Aluminum substitution in Ba2YCu3O7. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 36:8365-8368. [PMID: 9942653 DOI: 10.1103/physrevb.36.8365] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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343
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Singh GK, Singh NP, Garg SK. Studies on pathogenesis of fowl pox: virological study. Acta Virol 1987; 31:417-23. [PMID: 2891281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
One-month-old WLH chickens were inoculated with a field isolate of fowl pox virus (FPV) by intradermal (i.d.) and intratracheal (i.t.) routes. In intradermally infected chickens, the virus in titrable amounts was first detected in the skin at the inoculation site on day 2 and in lungs on day 4 followed by viraemia on the day 5 post-infection (p.i.). Subsequently the virus was recovered from liver, spleen, kidney and brain, but not from the heart. The chickens infected by i.t. route showed an almost similar outcome with minor differences as the virus was first demonstrated in the lungs on day 2 p.i., viraemia occurred on day 4 p.i. Initiation of pocks at the inoculation site in i.d. infected birds was observed on days 3 to 4 p.i., generalized cutaneous pock lesions appeared from 7 to 8 days p.i.
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344
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Paschoa AS, Wrenn ME, Singh NP, Bruenger FW, Miller SC, Cholewa M, Jones KW. Localization of vanadium-containing particles in the lungs of uranium/vanadium miners. Biol Trace Elem Res 1987; 13:275-82. [PMID: 24254682 DOI: 10.1007/bf02796638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Several geological formations of the Utah-Colorado mining region mined for uranium ore during and after World War II had been mined earlier for vanadium. Therefore, most miners and millers from that region were exposed to those metals' ores or tailings at one time or another. Preliminary investigation to determine uranium and vanadium retained in the lungs of a former uranium miner and miller from this region, who died of lung cancer (mesothelioma), showed a high nonuniform distribution of vanadium. This observation led to the hypothesis that the vanadium content in the lungs could be associated with inhaled particles. Further examination of spectra of characteristic X-rays obtained by scanning particle-induced X-ray emission (microPIXE) of an autopsy sample of this lung indicated that vanadium was indeed present in localized sites within the 20-μm spatial resolution of the proton beam. This work points out that the microPIXE-RBS (Rutherford backscattering) test for vanadium can be used for site localization of inhaled particles retained in the lungs. Further studies are in progress to: (i) locate uranium-bearing particles in lung tissues of former uranium miners and millers; and (ii) evaluate the local doses of alpha radiation received from these particles.
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345
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Panigrahi BP, Bhasin CP, Singh NP. Hyperbaric oxygen: an analysis of its therapeutic role. JOURNAL OF THE INDIAN MEDICAL ASSOCIATION 1986; 84:336-8. [PMID: 3585003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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346
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Abstract
We have developed a simple method to determine cell viability using two fluorescent dyes, Hoechst 33258 and acridine orange. When these dyes are used in combination, dead cells fluoresce brilliant blue and live cells fluoresce green. This method works over a range of dye concentrations (Hoechst 33258, 0.25-2 micrograms/ml; acridine orange, 1-5.0 micrograms/ml) and the fluorescence spectra of the two dyes are such that only one set of filters is required to visualize the effects of both dyes simultaneously. It is insensitive to a wide range of exogenous serum concentrations and is read with greater uniformity by different observers.
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347
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Singh NP, Medeiros DM. Effect of copper deficiency and Sodium intake upon liver lipid and mineral composition in the rat. Biol Trace Elem Res 1984; 6:423-9. [PMID: 24264179 DOI: 10.1007/bf02989259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/1984] [Accepted: 05/05/1984] [Indexed: 10/21/2022]
Abstract
The effect of copper and sodium intake upon liver cholesterol concentrations, fatty acid profile, and mineral concentrations were studied in the Long-Evans rat. Forty-eight male weaning rats were divided into three groups of 16 each and fed a semipurified diet containing either 0, 3, or 8 mg of added copper/kg of diet. At 100 d of age, half of the animals in each group were given 1% NaCl as drinking water and the other half was given deionized-distilled water for 12 wk. Copper deficiency in rats produced elevations in liver palmitate and oleate concentrations, but decreases in linoleate concentrations. The ratio of oleate:stearate was higher in copper deficient rats. Liver copper levels were decreased, but liver iron concentrations were elevated in copper deficient rats. Sodium intake did not have an effect on any of the parameters studied. These results suggested that dietary copper deficiency alters both liver mineral and fatty acid composition.
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348
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Abstract
In order to correlate the induction of sister-chromatid exchanges (SCE) to biological endpoints, and elucidate aspects of this relationships, 7,12-dimethylbenz[a]anthracene (DMBA) and methyl methanesulfonate (MMS), chemicals with different biological actions at different stages in development, have been evaluated for their ability to induce SCE at different gestational ages in the Sprague-Dawley rat. Transplacental exposure to these agents was accomplished by a recently developed intraperitoneal infusion technique to replenish metabolically degraded 5-bromo-2'-deoxyuridine used for SCE visualization. Maternal bone marrow and whole fetal tissue, fetal liver and fetal brain were compared. Day-9 embryo was found to be very sensitive to the effects of both agents, with the ability to induce SCE declining in development in whole fetus and fetal organs. The embryotoxic effects of the agents seem to be ones best correlated with the capacity of the agents to induce SCE. Also, fetal liver is more sensitive than fetal brain to the effects of DMBA compared with MMS, suggesting fetal metabolic activation may have occurred. Measurement of the amount of radiolabelled DMBA reaching the fetal tissue used to estimate SCE indicates that the amount of chemical reaching the fetus does not account for the increased sensitivity, especially at Day 9. Some factor(s) in development, such as differentiation stage, rather than the fetal accessibility to chemical, seem to be important in the induction of SCE in utero.
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349
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Singh NP, D'Ambrosio SM. Sister chromatid exchange frequency and cell cycle kinetics in cancer patients treated with cytostatic drugs. BASIC LIFE SCIENCES 1984; 29 Pt B:885-93. [PMID: 6597719 DOI: 10.1007/978-1-4684-4892-4_28] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The ability of various cytostatic drugs to induce sister chromatid exchanges (SCE) and to alter the progression of cells through mitosis was analyzed in lymphocytes cultured from cancer patients following various in vivo chemotherapy treatments. Control individuals exhibited 4.87 +/- 0.08 SCEs per metaphase. Patients being treated with cyclophosphamide (CP), mitomycin C (MMC), and/or cisplatinum (CPT) in combination with other drugs exhibited 3- to 5-fold greater levels of SCEs. Other cytostatic drugs: the plant alkaloids; vincristine (VCR); and homoharringtonine (HHT); the antibiotic, adriamycin (ADM); the folic acid antagonist, methotrexate (MTX); and the nucleotide analogue, dihydroazacytidine (HAC) did not appear to induce SCE levels significantly above controls. Most of the cytostatic drugs used in cancer patients appeared to delay the progression of cells through mitosis. All the drug protocols which included a known DNA-damaging agent induced SCE. There was no relationship between SCE and cell cycle kinetics. Thus, SCE appears to be a sensitive assay for monitoring the in vivo exposure of individuals to genotoxic agents.
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350
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Chang MJ, Singh NP, Turturro A, Hart RW. Characterization of cytotoxic effect of asbestos on normal human fibroblasts. ENVIRONMENTAL HEALTH PERSPECTIVES 1983; 51:237-239. [PMID: 6315364 PMCID: PMC1569318 DOI: 10.1289/ehp.8351237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Using viable cell counting and the incorporation of radioactive thymidine in cell TCA precipitate, we have attempted to separate the effects of asbestos on cell growth inhibition (reproductive failure) vs. cell killing. NIEHS crocidolite and NIEHS intermediate-sized chrysotile at a concentration of 10 micrograms/mL were studied. Cytotoxic effects were demonstrated with both types of asbestos. Thymidine incorporation expressed as cpm/viable cell was enhanced in the presence of either form of asbestos. It is concluded that both negatively charged crocidolite and positively charged chrysotile are toxic to human fibroblast cells in culture and exert their cell killing but not growth inhibition effect concurrently with a stimulation of DNA synthesis.
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