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

EDTA metal ammonium salt solution containing Fe3+, Co3+ or Cu2+ was studied to determine the pretreatment reagent that causes no denaturation of dentin collagen and promotes good adhesion to dentin. After application of EDTA 3-2 (Fe.NH4), EDTA 3-2 (Co.NH4) or EDTA 3-2 (Cu.NH4) at pH 7.4 on the dentin surface, the amount of Ca2+ demineralized and the tensile bond strength were measured. The pretreated dentin surfaces were also observed with SEM. No correlation was obtained between the amount of Ca2+ demineralized and the tensile bond strength. On the EDTA 3-2 (Fe.NH4) treated dentin a small amount of smear remained partially, but the tensile bond strength of 4-META/MMA-TBB resin to the dentin was higher than 13 MPa. This indicates that complete removal of the smear on dentin is not always necessary for better bonding.
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PMID:[Adhesion of 4-META/MMA-TBB resin to dentin treated with EDTA metal ammonium solutions. Effect of Fe.NH4, Co.NH4 or Cu.NH4 salts]. 251 58

We investigated the activity and the content of copper and zinc-containing superoxide dismutase (SOD) and superoxide anion (O2-) production in polymorphonuclear leukocytes (PMN) from healthy term newborn infants, very low birth wt infants, and healthy adults. SOD activity in PMN was measured with nitroblue tetrazolium reduction assay on PAGE, and the SOD content in PMN was determined with an ELISA using a monoclonal antibody against human copper and zinc-containing SOD. The activity and the content of SOD in the term neonatal PMN and VLBW-infants' PMN were significantly lower than those in the adults' PMN (term newborn infants, 6.6 +/- 0.6 U/mg protein and 170.4 +/- 16.3 ng/mg protein, n = 10; VLBW infants, 6.8 +/- 0.9 and 173.0 +/- 16.2, n = 6; adults, 10.3 +/- 0.6 and 241.9 +/- 13.3, n = 10; values were expressed as mean +/- SEM). Both the phorbol myristate acetate- and the N-formyl-methionyl-leucyl-phenylalanine-induced O2- production rates of VLBW-infants' PMN were significantly higher than those of the term neonatal PMN. The phorbol myristate acetate-induced O2- production rate of the term neonatal PMN was significantly lower than that of the adults' PMN. The phorbol myristate acetate-induced H2O2 production rate of the term neonatal PMN was significantly lower than that of the adults' PMN. The conversion rate from O2- to H2O2 of the neonatal PMN was similar to that of the adults' PMN.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Superoxide dismutase in polymorphonuclear leukocytes of term newborn infants and very low birth weight infants. 258 25

Intracellular structures of rapidly frozen biological tissues were observed in 3-D under a low-temperature scanning electron microscope using a newly developed side-entry type cryo-holder. The present low-temperature SEM is simple, easy to operate and effective for observing biological materials at high magnification. Biological tissues (the pancreas, small intestine, brown adipose tissue and Harderian gland) freshly removed from the mouse were immediately frozen in liquid propane cooled with liquid nitrogen, and their surfaces were manually fractured using a precooled razor blade in liquid nitrogen before introducing the cryo-holder into the SEM. When intracellular structures were revealed after appropriate sublimation, the specimens were coated with gold using a metal evaporator fitted to the side of the microscope column at one of the specimen chamber ports. The cryo-holder was connected to a copper braid coming from a liquid nitrogen reservoir to maintain a low temperature. Using this method, intracellular structures such as the mitochondria and endoplasmic reticulum were demonstrated at high magnifications. Ribosomal granules were discerned on the rough endoplasmic reticulum of the pancreatic acinar cells. Granular substances, presumably elementary particles, were also recognized on the mitochondrial cristae of the brown adipose tissue. The method was particularly effective for studying the 3-D configuration of lipid droplets which had been difficult to preserve by chemical fixation.
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PMID:High-resolution low-temperature scanning electron microscopy for observing intracellular structures of quick frozen biological specimens. 259 47

Nine young men and six elderly men and women ingested low-zinc, low-copper, and adequate diets for 2-wk periods. The Zn-Cu ratios averaged 2:1, 15:1, and 5:1. On day 8 of each period, subjects ingested doses of 70Zn and 65Cu so that net absorption could be determined. Zn absorption on the adequate diet was 39 +/- 3% (means +/- SEM) in young subjects and 21 +/- 1% (p less than 0.05) in the elderly subjects. During the low-Zn period, Zn absorption was higher as compared with that on the adequate diet in both young (64 +/- 5%, p less than 0.05) and elderly subjects (43 +/- 7%, p less than 0.05). Cu absorption on the adequate diet was 60 +/- 4% and 53 +/- 2% in young and elderly subjects, respectively. During the low-Cu period, Cu absorption was higher as compared with that on the adequate diet in the elderly subjects (67 +/- 4%, p less than 0.05). Cu absorption was higher in six of seven young subjects on the restricted Cu diet (p greater than 0.05). The effect upon absorption of the change in the Zn-Cu ratio was less than the effect of dietary restriction.
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PMID:Determination of zinc and copper absorption at three dietary Zn-Cu ratios by using stable isotope methods in young adult and elderly subjects. 259 36

The corrosion behavior of commercially available copper, nickel, and gold alloys for dental castings was investigated. The alloys investigated included: three copper alloys (76-87Cu, 6-11A1, 0-12Zn, 1-5Ni, 0-4Fe, 0.5-1.2Mn), two nickel alloys (68-78Ni, 12-16Cr, 4-14Mo, 0-1.7Be), and one gold alloy (77Au, 14Ag, 8Cu, 1Pd). Anodic and cathodic polarization curves, long-term immersion tests in saline and artificial saliva solutions, and dog crown studies were conducted to evaluate both the in vitro and in vivo corrosion characteristics of the alloys. All evaluations conducted demonstrated that the copper alloys were highly susceptible to corrosion attack. High corrosion currents were observed in the in vitro tests, and SEM of the alloys specimens showed significantly altered surfaces. The anodic polarization curves predicted that the beryllium-containing nickel alloy should be susceptible to localized corrosion and SEM revealed an etched surface with corrosion of certain microstructural features. No significant corrosion was predicted or observed for the non-beryllium nickel alloy and the gold alloy. The in vitro corrosion evaluations predicted the in vivo corrosion behavior for the alloys. Since the three copper alloys and the beryllium-containing nickel alloy demonstrated significant corrosion under the tested conditions, the use of these alloys for restorative procedures is questionable due to the release of significant levels of selected ions to the oral cavity.
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PMID:Corrosion of copper, nickel, and gold dental casting alloys: an in vitro and in vivo study. 261 43

This study was designed to determine whether the mechanical cyclic stressing that occurs during normal mastication contributes to margin breakdown of dental amalgam restorations. The method used appears to duplicate the mechanical stresses developed in vivo during mastication, as the result of tooth flexing. We evaluated one low-copper alloy--NTD--and three high-copper alloys--Dispersalloy, Phasealloy, and Tytin. We prepared simple amalgam restorations in a cavity centrally located in an aluminum beam. Each specimen received five periods of three-point cyclical loading (1.7 hertz, 4200 cycles at 37 degrees C). The margin area was subjected to SEM examination prior to and at the completion of each period of cycling. At the beginning of each period of cycling, beam deflection was set to establish a maximum theoretical stress of 1, 2, 4, 6, or 8 MPa. For all brands, cycling resulted in margin gap formation and surface wrinkling. Wrinkling in Dispersalloy occurred as a wide band of shallow wrinkles, whereas that in NTD occurred as a narrow band of deep wrinkles. At 21,000 cycles, very little void formation and fracturing had occurred in the Dispersalloy or NTD restorations. In contrast, the Phasealloy and Tytin restorations developed extensive fracturing even after 4200 cycles. Fracture surface analyses of Phasealloy and Tytin indicated that creep fatigue rupture was the fracture mechanism responsible for margin breakdown in these amalgam restorations, when subjected to cyclic compressive loading similar to that experienced during mastication.
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PMID:Amalgam margin breakdown caused by creep fatigue rupture. 263 4

The case of a patient is described in whom an osteosynthesis of the mandible was performed using copper wire about 60 years ago. The findings as well as the results obtained by SEM and ESMA are presented and discussed.
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PMID:[Evaluation of a mandibular copper wire osteosynthesis after 60 years of function]. 263 85

We compared trace element status in multiple sclerosis (MS) patients (n = 27) with and without treatment with corticosteroids and groups of healthy subjects. Concentrations of plasma ceruloplasmin, selenium, and zinc and erythrocyte (RBC) glutathione peroxidase, Se, and Zn were similar in all groups. RBC copper concentrations were significantly lower in MS patients than in control subjects (mean +/- SEM: 0.048 +/- 0.005 vs 0.060 +/- 0.002 mumol/g Hb) because of decreased RBC Cu with steroid therapy. RBC Zn-Cu ratios were significantly higher (14.9 +/- 1.0 vs 10.1 +/- 0.3) in MS patients than in control subjects, differing in both groups of MS patients. In MS and control subjects, RBC Cu correlated significantly with RBC Zn (r = 0.56, 0.49). Disease acuity and disability had no effect on trace-mineral status. These data suggest that in MS there is altered Cu and Zn homeostasis that may cause or result from the disease and is influenced by corticosteroid therapy. Systemic trace element alterations might provide clinically useful markers of MS.
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PMID:Trace element status in multiple sclerosis. 275 Jun 86

The effects of feeding supplementary dietary copper to a herd of 400 beef cows, were studied over a two year period. In the first year of the trial, the calves showed clinical signs of copper deficiency. There was improved growth following subcutaneous injection of copper ethylenediamine tetraacetate, and the treated calves had a 2.8% increase in adjusted weaning weights. In the second year of the trial pregnant cows were fed a basal ration of bromegrass silage, barley and minerals over the winter feeding period. The feed was supplemented with copper so that half received 5.5 mg/kg of copper on a dry matter basis and half 40 mg/kg. Calving occurred in the spring and half the calves were treated with injectable copper at birth and again at 12 weeks of age. There was no evidence of copper deficiency in the calves and there was no effect of high level copper supplementation on calf birth weight, or neutrophil candidacidal activity. Susceptibility to diarrhea varied in a complex fashion; morbidity was lowest in calves born to dams fed supplementary copper and highest in calves born to supplemented dams and injected with copper at birth. The cows and calves grazed the same copper deficient pasture over the summer. The average daily gain for calves born to supplemented cows was 0.999 +/- 0.010 kg/day (x +/- SEM) which was significantly greater than the 0.972 +/- 0.009 kg/day for calves from nonsupplemented dams (p = 0.044). The benefit of copper supplementation on 200 day weaning weight was estimated at 4.8 kg. Evidence of copper deficiency was seen when a herd test showed mean serum levels below 9 mumol/L and liver values below 0.09 mmol/kg wet matter.
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PMID:Diagnosis of copper deficiency and effects of supplementation in beef cows. 276 56

Plasma copper and ceruloplasmin concentrations at ages 0, 2, 4, 6, 9, and 12 mo were longitudinally evaluated in our Finnish nutritional survey of 200 infants. The infants, who were weaned by age 3.5 mo, were randomly assigned to receive either a liquid cow-milk-based formula containing 1.3 mumol Cu/L (n = 16) or the same formula supplemented with 7.8 mumol Cu/L as Cu sulfate (n = 16). They were compared with exclusively breast-fed infants. Plasma Cu and ceruloplasmin concentrations increased steadily and similarly in all three groups from 4.6 +/- 0.2 mumol/L (means +/- SEM) and 0.9 +/- 0.1 mumol/L, respectively, in umbilical samples to 19.7 +/- 0.3 mumol/L and 3.2 +/- 0.1 mumol/L, respectively, at age 12 mo. Our results indicate that concentrations of plasma Cu and ceruloplasmin in healthy full-term infants are resistant to dietary supplementation.
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PMID:Copper supplementation: failure to increase plasma copper and ceruloplasmin concentrations in healthy infants. 280 90


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