Showing papers by "Pramod K. Srivastava published in 1986"

Tumor rejection antigens of chemically induced sarcomas of inbred mice.

Abstract: Chemically induced sarcomas of inbred mice are immunogenic in syngeneic hosts, and preimmunization with tumor cells leads to resistance to subsequent tumor transplants. The tumor rejection antigens (TRAs) that mediate this reaction are highly specific for each tumor; cross-protection between different syngeneic sarcomas is rare. Isolated membrane and cytosol fractions from two antigenically distinct BALB/c sarcomas, Meth A and CMS5, have TRA activity, and biochemical characterization of the active components from the cytosol and plasma membranes of these two tumors identified a glycoprotein of Mr 96,000. Immunization with unfractionated Meth A cytosol frequently leads to tumor enhancement, but the tumor-enhancing activity (TEA) is lost on fractionation and TRA activity becomes demonstrable. As Meth A and CMS5 lack expression of murine leukemia virus (MuLV) antigens or transcripts, MuLV-related antigens cannot be involved in the TEA or TRA activities of these tumors. In contrast to the lack of cross-reactivity between Meth A and CMS5 TRAs in transplantation tests, rabbit antiserum prepared against the Meth A Mr 96,000 antigen reacted with the CMS5 Mr 96,000 antigen. In view of the biochemical and antigenic similarities of Meth A and CMS5 TRAs, we propose that structurally related but distinct Mr 96,000 glycoproteins are expressed in chemically induced sarcomas and that these molecules are responsible for the individually specific immunogenicity of these tumors.

Fetal translocation and metabolism of PAH obtained from coal fly ash given intratracheally to pregnant rats.

Abstract: Polycyclic aromatic hydrocarbons (PAH) were extracted from coal fly ash collected from the electrostatic precipitator of a thermal power plant. The PAH extract was given intratracheally daily to pregnant rats (2 mg/100 g body weight) on d 18 and 19 of gestation. In addition on d 19 of gestation rats were also given [3H]benzo[a]pyrene intratracheally. Rats were sacrificed on d 20 of gestation, and the distribution of [3H]benzo[a]pyrene radioactivity and PAH of coal fly ash was studied in maternal lung, liver, and placenta, as well as in the liver and lung of the fetus. The radioactivity of intratracheally given benzo[a]pyrene was found in liver (68%), placenta (4%), fetal lung (1.9%), and fetal liver (1.4%) of maternal lung. Intratracheally administered PAH of coal fly ash were translocated to maternal liver and placenta, as well as to the liver and lung of the fetus. PAH of coal fly ash were also metabolized to several minor and major metabolites by maternal lung, liver, and placenta, as well as by the maternal fetal liver and lung. Some of the PAH metabolites in lung and liver were common; however, the major metabolite of liver, M-16, was different from the major metabolite M-16 of lung. The major PAH metabolite of placenta, M-5, and fetal liver, F-12, were common PAH metabolites. M-2 and M-6 of the placenta and F-5 and F-10 of the fetal lung were also common.

Inhibition of coal fly ash polycyclic aromatic hydrocarbons and metals induced mixed-function oxidase activity in rat lung and liver by vitamin A and citrate.

Abstract: Administration of benzene-soluble fraction (FAE) and benzene-insoluble fraction (FAR) of fly ash for 3 consecutive days to rats significantly raised cytochrome P-450 levels, aryl hydrocarbon hydroxylase (AHH) activity, and glutathione S-transferase activity in liver. This treatment also significantly increased pulmonary AHH and glutathione S-transferase activity. Intratracheal administration of FAR (5 mg/100 g body weight) alone for 6 consecutive days also significantly increased hepatic cytochrome P-450 levels and the activity of glutathione S-transferase. Intragastric administration of retinyl palmitate (5000 IU/100 g body weight), along with intratracheal FAE and FAR administration, significantly reduced P-450 levels, activity of glutathione S-transferase in liver, and activity of AHH and glutathione S-transferase in lung of rats. Intraperitoneal administration of citrate (40 mg/100 g body weight) along with FAR significantly reduced FAR-induced increase in hepatic cytochrome P-450 levels and glutathione S-transferase activity. The activity of AHH was not affected by these treatments.

Phosphatidylcholine metabolism in lung microsomes and lung surfactant of rats exposed intratracheally to coal fly ash

Abstract: The effect of intratracheal administration of fly ash has been studied on lung micro‐somal and lung surfactant phosphatidylcholine (PC) metabolism in rats using [methyl‐14C]choline and [methyl‐14C]methionine. Fly‐ash administration significantly increased total phospholipids, PC, phosphatidylethanolamine (PE), and phosphati‐dylglycerol (PC) of lung surfactant. Fly‐ash administration stimulated the formation of lung microsomal PC (as measured by the incorporation of labeled precursors) both by the cytidine 5'‐diphosphate (CDP)‐choline pathway and by the N‐methylation pathway, but this stimulation was fourfold higher in the latter case and only twofold higher in the former as compared to the control. Likewise, the secretion of PC formed by the N‐methylation pathway was sixfold higher as compared to the control whereas secretion of PC formed by the CDP‐choline pathway was only threefold higher as compared to the control. Fly‐ash administration further increased total saturation and decreased unsaturation in ...

Cervical myelopathy in diffuse idiopathic skeletal hyperosteosis.

Abstract: ~,\" The case of a rapidly progressive cervical myelopathy in a 64-year-old man is presented. Radiological studies revealed a partial extradural block, which at surgery was found to be a focal fibrous, calcified mass associated with the ligamentum flavum. On the basis of the underlying disorder of diffuse idiopathic skeletal hyperostosis (DISH), the etiology of this compression was concluded to be focal fibrous proliferation and dystrophic calcification. The neurological complications of DISH are reviewed. The authors are not aware of any other reports of this cause of myelopathy associated with DISH.

Hepatic microsomal phospholipids in rats exposed intratracheally to coal fly ash.

Abstract: The effects of intratracheal administration of fly ash (50 mg/kg body weight, daily for 7 days) on hepatic microsomal phospholipid metabolism has been studied in rats using various phospholipid precursors, viz NaH2(32)PO4, (methyl-14C)-choline, and (methyl-14C)-methionine. Fly ash administration significantly increased microsomal phosphatidylcholine (PC), and lysophosphatidylcholine (LPC). The incorporation of NaH2(32)PO4 into total liver phospholipids, PC and Phosphatidyl ethanolamine (PE) was significantly increased in fly ash-treated rats as compared to the control. Fly ash administration also increased the incorporation of (methyl-14C)-choline into microsomal PC. Incorporation of (methyl-14C)-methionine into microsomal PC was not affected. Fly ash administration decreased the per cent distribution of arachidonic acid in PC and PE and increased that of oleic acid in PC and of linoleic acid in PE.

Sodium Homeostasis with Special Reference to Fractional Excretion of Sodium and Plasma Prostaglandin E-1 in Elderly Hypertensives in Essential and Renovascular Hypertension

Abstract: Since the kidney plays a dominant role in the maintenance of volume in the body fluid spaces through its influence on sodium and water excretion; it must be involved in all forms of hypertension. As Guyton (1) has indicated renal perfusion pressure is a major determinant of sodium and water excretion and hypertension could not be maintained, unless the relationship had been altered between renal perfusion pressure and its output of sodium and water. Korner et al (2) have proposed that excessive activity of sympathetic nervous system and a failure of the kidney to excrete sufficient sodium and water in response to elevation of blood pressure. The presumed relationship between the primary mechanism behind the development of hypertension sodium homeostasis and use of diuretics as antihypertensive agents all over the world, but only recently we have recognized the various hyponatremic syndromes. Little attention has been paid to the special needs of geriatric patients who tend to excrete more sodium because of poor tubular concentration, especially in the tropics. Labeuw et al (3) have found that fractional excretion of sodium is a helpful denominator in planning the administration of diuretics. A consideration of these factors led the authors to undertake the present study of fractional excretion of sodium and plasma PGE-1 in elderly hypertensives in the tropics.