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Biomedical subjects

J Camps

Publications and source records attributed to J Camps.

At least 109 records · Page 6Linked to original sources
PubMed1992

[The coherence between 3 evaluation methods of biocompatibility].

Three successive series of tests (the primary including cytocompatibility tests and the secondary in vivo and usage tests) can be used to evaluate the biocompatibility of dental materials. The products are only submitted to secondary tests in case of satisfactory results obtained with primary tests. A coherence between the results of primary and secondary tests is necessary before performing in vivo tests. The aim of this paper is to study the coherence between two primary tests and a secondary test. The biocompatibility of Sealite and a pulp canal sealer was studied 4 and 12 weeks after mixing, according to two primary models (cell culture on agarose and a toxicity study of the extraction products) and a secondary model (intrabony implantation in the rabbit). The two primary tests gave different results for Sealite and the pulp canal sealer. Only the agarose cell culture and the intrabony implantation in the rabbit have given similar statistical results. The biological evaluation of biomaterials should begin with a study of the mechanism of action of the cytotoxic products using several in vitro tests. These latter are unable to predict the behaviour of a biomaterial in an in vivo test.

Animals↗
PubMed1991

Quantitative measurement of fibrosis in pancreatic tissue. Evaluation of a colorimetric method.

A colorimetric method has been used to quantify the collagen contained in 23 specimens of pancreatic tissue (11 controls and 12 chronic pancreatitis). The method takes advantage of the selective capacity of Sirius red to stain collagen protein and of rapid green to stain noncollagen protein. The results obtained by this method were compared with those of standard morphometry to determine tissue fibrosis. With the morphometric method, the values of the control group were 6.6 +/- 4.0% (fiber area/total area), and those of chronic pancreatitis 66.0 +/- 19.0% (difference 59.4, 95% confidence interval for difference: 47.2-71.6, P less than 0.001). The values obtained with the colorimetric method were 89.1 +/- 11.6 micrograms collagen/mg total protein in the control group, and 132.7 +/- 25.3 micrograms collagen/mg total protein in the chronic pancreatitis group (difference 43.6, 95% confidence interval for difference: 26.3-61.0, P less than 0.001). A highly significant correlation (r = 0.847; p less than 0.001) was observed between the amount of collagen measured colorimetrically and the degree of fibrosis determined morphometrically. These results demonstrate that the colorimetric method is a reproducible, simple, and rapid technique to quantitate fibrosis in histological preparations of pancreatic tissue.

Alcoholism↗
PubMed1991

Effects of 5-hydroxytryptamine on capillary and arteriovenous anastomotic blood flow in the human hand and forearm and in the pig hind leg.

The effects of intraarterially infused serotonin (5-HT) on capillary and arteriovenous anastomotic (AVA) blood flow were investigated in the hand and forearm of 19 healthy volunteers, and in the hind leg of six anesthetized pigs using radioactive microspheres with a diameter of 15 microns. The 5-HT2-receptor antagonist ketan-serin was used in an attempt to identify the receptors involved. None of the drugs in the doses used induced systemic hemodynamic effects. Low doses of 5-HT significantly increased forearm blood flow with a maximum response at the dose of 1 ng/kg/min (68 +/- 14%, p less than 0.05), whereas only at the highest dose of 80 ng/kg/min was a net decrease in forearm blood flow measured (-28 +/- 6%, p less than 0.05). Conversely, finger blood flow was not influenced by the lower doses of 5-HT, whereas a major reduction was observed at the highest dose (-90 +/- 3%). Ketanserin increased both total forearm blood flow and AVA blood flow. The drug blunted the constrictor response to 5-HT in the forearm but only slightly attenuated this response in the finger. The percentage AVA blood flow in the human hand and forearm was not influenced by an infusion of 5-HT at 80 ng/kg/min alone. However, after pretreatment with ketanserin, which itself increased the AVA component, this dose of 5-HT significantly reduced AVA flow. In the pig, total femoral blood flow was not influenced by 5-HT, but AVA blood flow was significantly reduced and capillary skin blood flow increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Obturation of lateral canals: necessary therapy or radiological satisfaction?].

Lateral canals are frequently endo-periodontal pathways. Filling lateral canals is not always necessary for a successful root canal treatment. Endo-perio lesions are bacterial in origin and lateral canals filling is only necessary when there is a chance for bacterial contamination: pulpal necroses, and deep periodontal pockets surrounding a lateral canal.

Bacterial Infections↗
PubMed1991

[A comparative study of the in vitro biocompatibility of 2 root canal sealing cements].

The aim of this study was to evaluate the biocompatibility of radicular sealing cements with agarose cell culture. The two cements studied were Sealite and Pulp Canal Sealer with different mixing times. In the experimental conditions used the cytocompatibility of Sealite was better than that of Pulp Canal Sealer. The cytotoxicity of both products was not negligible and corresponded to those of other studies with Pulp Canal Sealer and a cement with amount similar composition to Sealite. Because theses cements are currently used with success in humans, the results of this test raise the question of extrapolation to man.

Animals↗
PubMed1991

[New method of canal preparation and new instruments: The Canal Master].

The Canal Master is a new instrument for root canal preparation. Its working portion measures 2 mm and this instrument presents a non aggressive tip. This technique uses mechanical instruments for the straight portion of the canal and manual instruments for the curved portion. Clinically this technique gives good results but is more longer than others.

Adult↗
PubMed1990

Toxicity of lovastatin in rats with experimentally induced nephrotic syndrome.

The effect of lovastatin on the hyperlipidemia induced in rats with experimental nephrotic syndrome was investigated; toxicity and the effects on common blood chemistry parameters were also assessed. Hyperlipoproteinemia in this particular model is associated with an increase in hepatic synthesis of lipoproteins, and treatment with lovastatin could be the most suitable, since the drug inhibits cellular cholesterol synthesis. Lovastatin treatment resulted in a considerable reduction in plasma cholesterol and triglyceride levels. The decrease in cholesterol levels with treatment was mainly confined to the low-density lipoproteins (LDL) although there was a reduction in the nephrotic-syndrome-induced incremental level of high-density lipoprotein cholesterol. Other lipoprotein fractions were unaffected by lovastatin. LDL apoprotein B was increased in both groups of rats, but to a lesser degree in the lovastatin-treated group, suggesting a double effect, inhibition of both, cholesterol and apoprotein synthesis. Both groups of rats showed a certain degree of renal impairment as shown by significant elevations in plasma urea and creatinine levels. Hepatic damage was also observed, chemically and microscopically, in both groups of rats, being more pronounced in those rats treated with lovastatin in which a 50% mortality ensued after 2 weeks of treatment. At the dosage used this may have some implications in its therapeutic use in certain conditions.

Animals↗
PubMed1990

[Physico-chemical properties of 4 endodontic sealing cements].

Four endodontic sealers were compared with two series of tests, in thin layer and in 10 mm long and 5 mm diameter rods. Under these conditions, the Pulp Canal Sealer showed the best ability to present a thin layer and the same flow than the Cortisomol. Its setting time was 15 minutes. Forty-eight hours later, the Sealite showed a very good tightness compared to the other sealers. At 30 days, the Pulp Canal Sealer and the OZn-Eugénol were the tightest ones. Less water was absorbed with the Cortisomal and the Sealite. Is there, for these sealers, any correlation between water-absorbtion and tightness?

Absorption↗
PubMed1990

[Biomechanical behavior of the pulpectomized tooth].

No accurate information is in fact available regarding the biomechanical properties of devitalized teeth. The time frame seems to be a more significant factor than nature of the pulpectomy itself, as far as the risk of fracture is concerned. The use of a pivot or other form of root anchorage does not seem to play a determining role in the long-term reliability of restorations. Partial restorations can be substituted for full coronoperipheral reconstruction insofar as they protect the cusps. Each clinical situation must be matched with the appropriate reconstruction.

Crowns↗
PubMed1990

[Study of the section of different brands of K files and broaches].

The authors of this article observed the cross section of different brands of K file and reamer, in order to compare the reality to the square or triangular symbol. On an other hand, they defined the ideal cross section of the endodontic instrument according to the user's requirements, and studied the most approaching one.

Root Canal Therapy↗
PubMed1990

[Efficiency factors in endodontic instruments. Study of linear movement].

This study of the efficiency of endodontic tools in a linear motion values different parameters. The cross section seems to be the most important factor. The triangular section instruments are more efficient than the square section ones, but are more easily worn. The helical angle, the outline and the diameter have no influence on the efficiency.

Efficiency↗
PubMed1990

[Evaluation of four methods of preparing curved canals].

The authors used the protocol provided by Bramante, Berbert and Borges, to evaluate the respect of the canal position during the curved canal preparation. They compared four preparation types, two hand preparation and two engine driven ones: the step back technique, the anticurvature filing technique, the contact shaping technique, the canal finder. A statistic analysis of the results shows that the preparation is done to the detriment of the furcation wall and that only the step back technique is not suitable for the curved canal preparation.

Dental Pulp Cavity↗