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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concentrations of nitrate, nitrite, N-nitroso compounds and bacteria were measured in 96 samples of fasting gastric juice, pH 0.90-8.50, obtained from 56 individuals just before or at various times (8 days - 1 year) after gastric operation. The mean pH of the post-operative samples [4.66 +/- 0.39 (SEM)] was significantly higher than that of the pre-operative ones [3.29 +/- 0.33 (SEM)]. A positive correlation with pH was observed for the concentrations of total and nitrate-reducing bacteria (median values 5.0 X 10(5) organisms/ml and 9.2 X 10(4) organisms/ml, respectively, for samples with pH greater than or equal to 1.2 X 10(3) organisms/ml and 0 organisms/ml, respectively, for samples with pH less than or equal to 2.5) and nitrite [mean values 22.5 +/- 3.1 (SEM) microM and 3.20 +/- 0.5 (SEM) microM for samples with pH greater than or equal to 6.5 and pH less than or equal to 2.5, respectively]. No correlation with pH was seen for the concentrations of nitrate [mean value 0.48 +/- 0.06 (SEM) mM] or N-nitroso compounds [mean value 0.30 +/- 0.06 (SEM) microM]. The concentrations of bacteria and nitrite, although increased in hypochlorhydric individuals, were lower than those reported for corresponding individuals in other, primarily British, studies. It is suggested that the relatively low concentrations of nitrite observed in our hypochlorhydric population may account for the absence of elevated concentrations of N-nitroso compounds and that the latter phenomenon may be related to the relatively low frequency of gastric cancer in Greece.
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PMID:Studies in gastric carcinogenesis. II. Absence of elevated concentrations of N-nitroso compounds in the gastric juice of Greek hypochlorhydric individuals. 401 83

Since specular microscopy of the cornea offers the opportunity to observe and measure cells in vivo without any outside interference this method forms an unrivalled basis for estimation of tissue shrinkage during various preparatory methods. Therefore a study was performed with the purpose of evaluating the degree of artifacts in each preparatory step from the living tissue "in vivo" to the final SEM specimen. The study was performed on rabbit corneas, the endothelium serving as measuring target. The in vivo state was recorded by specular microscopy. Unfixed corneas were studied by light microscopy unstained and stained by alizarin red S or silver nitrate. Fixation was performed intracamerally with 1.5% glutaraldehyde (Gla) by a pH, osmolarity, viscosity and intraocular pressure identical with the physiological values of rabbit eyes. Fixation was completed by immersion in 2.5% Gla for 1/2 h. Gla-fixed corneas were evaluated as above before osmification. Dehydration was performed either by graded acetone, by acetone in a gradient-free system, both followed by critical point drying (CPD). At all steps cells were counted using the same reference frame. The number of cells/mm2 was estimated and statistical analysis showed a shrinkage of 22 per cent (area) in unfixed tissue, 26 per cent (area) in normally dehydrated tissue and 37 per cent (area) in gradient free dehydrated tissue processed for SEM.
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PMID:Shrinkage in preparatory steps for SEM. A study on rabbit corneal endothelium. 616 7

Medusa cells, amoeboid variants of the eosinophil with pseudopod-like processes, were examined by light microscopy (LM), transmission electron microscopy (TEM), the secondary electron imaging (SEI) and the backscattered electron imaging (BEI) modes of the scanning electron microscope. TEM was performed on rare medusa cells found in leukocyte concentrate preparations where the ion contents of the collection and fixation media were balanced so that divalent cations such as calcium and magnesium were not sequestered. LM, SEI and BEI studies were performed principally on cytochemically-stained films of leukocyte concentrate preparations on microscope slides or coverslips. These films of patients with eosinophilia contained many medusa cells and much higher ratios of medusa cells to eosinophils than critical point-dried specimens, if they were prepared as for routine hematologic examination, and precautions were taken to insure that calcium and magnesium ions in collection and fixation media were not sequestered. After brief glutaraldehyde fixation, the smears were stained with either osmium tetramethylethylenediamine (Os-TMEDA) for acid mucopolysaccharides, or 3,3'-diaminobenzidine (DAB)/hydrogen peroxide medium for peroxidases. The Os-TMEDA was sufficiently conductive for SEM. Chelation of the oxidatively-polymerized DAB dye with copper nitrate rendered it conductive. These conductive and electron-opaque stains permitted the correlation of SEI with BEI on individual cells, their unambiguous identification as eosinophils or medusa cells and their differentiation from other leukocytes by virtue of content and/or size of their granules and their degree of nuclear segmentation.
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PMID:Studies of eosinophil medusa cells by electron imaging modes. 641 7

The purpose of this paper is to show, by noninvasive measurements, previously undocumented effects on cardiac work of the nitrate coronary vasodilator Pentaerythritol Tetranitrate (Peritrate). The chew-and-swallow 40-mg tablets of this drug were given to 10 patients of type II AHA classification. The Diastolic Time Tension Index/Systolic Time Tension Index Ratio increased significantly from 1.15 (+/- 0.11 SEM) to 1.46 (+/- 0.13), p less than 0.05. The Double Product decreased significantly from 9813 (+/- 606) to 8336 (+/- 497), p less than 0.01. The Triple Product also decreased significantly from 3223 (+/- 235) to 2425 (+/- 206), p less than 0.01. The percent diastole of the R-R interval increased significantly from 65% (+/- 2.44) to 70% (+/- 1.73) p less than 0.05, while no significant change in heart rate occurred (63.2 bts/min to 62.4 bts/min). Correspondingly, there was a decrease of systolic time interval, from 0.33 second (+/- 0.2) to 0.29 second (+/- .01) p less than 0.01. A significant decrease in blood pressure was also noted. Systolic BP dropped from 155 (+/- 8.0) to 134 (+/- 7.2), p less than 0.01. Diastolic BP dropped from 89.2 (+/- 2.8) to 79.2 (+/- 2.2), p less than 0.01. This study shows that Peritrate produced significantly favorable changes in all the cited indicators of cardiac work.
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PMID:Effect of coronary vasodilating drug on myocardial work. 709 70

In uranyl nitrate (UN)-induced acute renal failure (ARF) glomerular ultrafiltration coefficient (K(f)) decreases because of unknown reasons. Since transport of water across the glomerular capillary wall occurs predominantly extracellularly through the endothelial fenestrae (EF), a reduction in the diameter and/or the density of EF can reduce the extracellular filtration area and the glomerular K(f). To examine this possibility, ARF was induced in rats by intravenous administration of UN in low (15 mg/kg) and high doses (25 mg/kg). Fenestral density ( x+/-SEM) per 5 cm(2) from the scanning electron micrographs (x30,000) was 107+/-10, 103+/-9, and 101+/-11 at 2, 7, and 17 h after the intravenous administration of bicarbonate saline to the control rats. In the low-dose UN group the EF density was 91+/-2, 52+/-8, and 45+/-11 at 2, 7, and 17 h after the injection, whereas for the high-dose group at corresponding time intervals the EF density was 95+/-3, 54+/-9, and 44+/-10. Fenestral diameters, in Angstrom units ( x+/-SEM), were 751+/-53, 765+/-43, and 764+/-37 at 2, 7, and 17 h after the injection of bicarbonate saline to control rats. At corresponding intervals after the administration of UN, the fenestral diameters were 501+/-61, 472+/-28, and 438+/-98 for the low-dose group and 525+/-43, 470+/-39, and 440+/-56 for the high-dose group. 2, 7, and 17 h after the injection of UN, fenestral area of the low-dose group decreased to 52.1, 30.1, and 24.6% of the controls, whereas in the high-dose group, the fenestral area declined to 54.3, 30.2, and 23.6% of the controls. Administration of UN (15 mg/kg) to sodium-loaded rats did not alter renal function or endothelial cell morphology. It is suggested that in UN-induced ARF the morphological alterations in endothelial cells reduce the K(f) of glomerular capillaries by reducing the filtration area.
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PMID:Glomerular endothelial cells in uranyl nitrate-induced acute renal failure in rats. 735 Jan 92

Despite the potential relevance of the L-arginine-nitric oxide (NO) pathway in the pathophysiology of pulmonary hypertension, no in vivo studies of the kinetics of arginine and NO have been conducted previously in this population. The terminal guanidino N-atom of L-arginine is the precursor for NO, which is oxidized to the stable inorganic nitrogen oxides, nitrite (NO2-) and nitrate (NO3-). Thus, synthesized NO is detected in serum or urine as NO2- and NO3-. The purpose of this investigation was to compare studies of whole body arginine metabolism twice in nine patients with persistent pulmonary hypertension of the newborn (PPHN), using a primed constant i.v. infusion of L-[guanidino-15N2,5,5(2)H2]arginine and L-[5,5,5(2)H3]leucine, first during acute pulmonary vasoconstriction and again during convalescence, and thereby to characterize quantitative aspects of whole body arginine kinetics and NO production, as estimated from the rate of transfer of the 15N-guanidino-label of arginine to urinary nitrate (15NO3-). Arginine flux rates were 84.1 +/- 8.6 mumol.kg-1 h-1 (mean +/- SEM) during acute pulmonary hypertension and increased to 125 +/- 13.2 (p < 0.05) during convalescence, whereas leucine fluxes were unchanged (168.5 +/- 15 versus 178.8 +/- 10.2 mumol.kg-1 h-1), and comparable to those reported in healthy newborns. During convalescence total urinary nitrate excreted increased by 66% (p < 0.05), urinary 15NO3- increased from 0.29 +/- 0.07 to 0.74 +/- 0.15 mumol.d-1 (p < 0.05), and the rate of plasma arginine conversion to NO increased from 10.3 +/- 2.2 to 45.6 +/- 13 mumol.d-1 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Whole body arginine metabolism and nitric oxide synthesis in newborns with persistent pulmonary hypertension. 747 91

The in vitro and vivo effects of lead on the NMDA-receptors in adult and juvenile mice were studied by means of receptor binding assays. Adult female NMRI-mice received 100 and 1,000 ppm lead as nitrate in their drinking water for 30 and 90 days. Perinatal exposure was achieved by treating gestating mice from the 5th day post conception with 0, 100 or 1,000 ppm lead in their drinking water. Characterization of the NMDA N-methyl-D-aspartate)-receptor was carried out ex vivo using binding studies on homogenates of the forebrain with the non competitive NMDA-antagonist 3H-MK-801. In vitro, complete inhibition of the radioligand binding was found with half maximal inhibiting concentrations (IC50-values) of 19.7 +/- 2.6 microM (SEM) in absence of amino acids and 9.5 +/- 0.9 in presence of glutamate and glycine. These concentrations are in a range which could be achieved in vivo, e.g. the lead content in the forebrain of juvenile mice treated with 1,000 ppm lead was 10.0 +/- 1.8 mumol/kg wet weight. It was speculated that lead binds at the zinc binding site. In the presence of amino acids and divalent cations, such as calcium or magnesium, low lead concentrations lead to a significant increase in receptor affinity. Analysis of the saturation experiments carried out on forebrain homogenates of lead-treated animals showed a slight increase in receptor density of 13 or 15% with an unchanged Kd-value only in the adult animals treated with 100 ppm lead and in absence of stimulating amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vitro and in vivo effects of lead on specific 3H-MK-801 binding to NMDA-receptors in the brain of mice. 756 90

Similar to mercuric chloride, silver nitrate has recently been shown to induce IgG autoantibodies targeting the nucleolar 34-kDa protein fibrillarin i SJL (H-2s) mice. In the present study we show that the autoimmunogenic effect of silver is dependent on intact T-cell function since SJL/N mice homozygous for the nude mutation (athymic), in contrast to the functionally T-cell-intact SJL/N-nu/+ littermates, did not develop anti-nucleolar/anti-fibrillarin autoantibodies (ANoA/AFA). The genetic susceptibility for silver-induced AFA was localized to the H-2A locus using congenic and intra-H-2-recombinant strains. However, background (non-H-2) genetic factors substantially influenced both the response rate and the titer of ANoA/AFA attained. Strains bearing H-2As on the SJL and A backgrounds (SJL, A.SW, A.TH) showed 100% response rate and high ANoA titers (3750 +/- 246, mean reciprocal titer +/- SEM), whereas H-2As mice on the B10 background (B10.S) showed 60% response rate and significantly lower ANoA titers (1170 +/- 305) in the responding mice. Expression of H-2E [B10.S(9R) mice] further reduced the response rate (22%) and the ANoA titer (640 +/- 0). A suppressive effect on the B10 background has previously been observed in mercury treatment, but the effect was stronger in silver-treated mice. Two major differences were noted between silver- and mercury-induced murine autoimmunity. First, silver-treated mice did not show elevated titers of other autoantibody specificities, specifically not of antichromatin and anti-histone antibodies, which develop in mercury-treated SJL mice.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Genetic susceptibility to silver-induced anti-fibrillarin autoantibodies in mice. 758 39

Gallium nitrate is a potent antiresorptive drug that has been extensively tested in patients with accelerated bone turnover. We have evaluated the effects of this new agent in a pilot multicenter trial of 49 patients with advanced Paget's disease of bone. Patients were randomized to receive 0.05, 0.25, or 0.5 mg/kg.day gallium nitrate administered by sc injection in two 14-day cycles. Serum alkaline phosphatase, fasting 2-h urinary hydroxyproline and N- telopeptide collagen cross-links excretion, and quality of life were assessed every 2 weeks for 12 weeks. The group mean alkaline phosphatase activity at baseline was 854 +/- 100 (+/- SEM) IU/L. The mean changes from baseline to week 12 in serum alkaline phosphatase were +0.5%, -24%, and -31%, respectively, for the three doses tested. The differences for each of the higher dose levels (0.25 and 0.5 mg/kg.day) was statistically significant (P < or = 0.05), and nearly half of the patients treated with the 0.5 mg/kg.day dose achieved a 50% or more reduction in enzyme activity. The nadir value in hydroxyproline excretion occurred at 10 weeks, with mean changes of +9%, -10%, and -17% for the 0.05, 0.25, and 0.5 mg/kg.day doses, respectively; the difference was significant only at the 0.5 mg/kg.day level (P < 0.01). Urinary collagen cross-link excretion showed a significant decrease at the 0.25 and 0.5 mg/kg.day doses. We also observed a definite, but nonsignificant, trend for improved quality of life in patients treated at the highest drug dose. Minor discomfort at the injection site was frequently reported, but did not lead to interruption of therapy. Our results in these patients who had received moderate to extensive prior therapies with other drugs show that cyclical, low dose, sc administration of gallium nitrate is safe and effective for treating patients with advanced Paget's disease of bone.
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PMID:A multicenter trial of low dose gallium nitrate in patients with advanced Paget's disease of bone. 785 26

Results from in vitro experiments suggest that development of nitrate tolerance is due to a depletion of vascular thiol compounds (ie, cysteine and glutathione [GSH]) necessary for the bioconversion of organic nitrates. However, it is unknown whether in vivo tolerance development is associated with changes in thiol levels. This study measures plasma and vessel tissue GSH and cysteine levels in nontolerant rats, nitrate-tolerant rats, and rats treated with the two characteristically different thiol donors N-acetyl-L-cysteine and L-2-oxothiazolidine-4-carboxylic acid (OXO). Chronically catheterized conscious rats received an intravenous infusion of either nitroglycerin (NTG, 0.2 mg/h) or matching placebo for 3 days. At day 3, the hypotensive effect of 2.5 mg NTG/kg was decreased by 74 +/- 6% (mean +/- SEM, P < .05) in the NTG-treated group (n = 7), indicating the development of tolerance. No change in the hypotensive effect of NTG was seen in the placebo group (n = 6, P > .05). Hemodynamic tolerance is not associated with changes in aorta cysteine or GSH levels as compared with the placebo group (cysteine, 77 +/- 14 versus 57 +/- 11 [mean + SEM] nmol/g; GSH, 414 +/- 62 versus 399 +/- 89 nmol/g; P > .05). However, the increase in vascular thiol levels seen after OXO treatment in nontolerant rats is completely absent in nitrate-tolerant animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nitrate tolerance in vivo is not associated with depletion of arterial or venous thiol levels. 826 84


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