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Biomedical subjects

H Hamel

Publications and source records attributed to H Hamel.

At least 19 recordsLinked to original sources
PubMed2002

Microleakage of class V composite restorations following Er:YAG and Nd:YAP laser irradiation compared to acid-etch: an In vitro study.

This study compared microleakage at enamel/composite and dentine/composite interfaces following Er:YAG laser, Nd:YAP laser, or acid-etch preparation. Class V cavities produced on the lingual and buccal surfaces of 20 extracted carie- and restoration-free human teeth were randomly assigned to four groups of 10 cavities. Teeth were treated with 37% phosphoric acid and primer (group 1), irradiated with an Er:YAG laser (group 2) or an Nd:YAP laser (group 3), or served as controls (group 4). The specimens were restored with Scotchbond Multipurpose/Z100 (3M), stored in physiological solution at 37 degrees C for 7 days, thermocycled 500 times between 5 degrees C and 55 degrees C, placed in a 0.5% solution of basic fuchsin for 48 h, embedded in resin, and sectioned. Microleakage was assessed according to the depth of dye penetration along the restorative composite. The results showed that irradiation with Er:YAG and Nd:YAP lasers did not produce a good seal. Mean microleakage was greater than with acid-etch and statistically comparable to that of control cavities (Kruskal-Wallis test).

Acid Etching, Dental↗
PubMed2002

[Pulmonary edema and tocolysis with beta-agonists].

It is not unusual for respiratory specialists to be called to deal with respiratory problems in pregnancy. However, some conditions, such as tocolysis-induced pulmonary edema, although common, are largely unknown to our specialty. We report on the cases of three pregnant women, who developed pulmonary edema in the context of tocolysis with the intra-venous infusion of B-agonists. In all three patients, tocolysis was required because contraction developed well before term. Triple pregnancy was present in one patient. In another patient, mechanical ventilation was required. The outcome was good with full recovery in all three cases.

Adrenergic beta-Agonists↗
PubMed1999

Amplifications of DNA primase 1 (PRIM1) in human osteosarcoma.

We studied the involvement of PRIM1 in osteosarcoma by differential display, Northern and Southern hybridization, as well as fluorescence in situ hybridization (FISH) on interphase nuclei. In total, 22 pediatric oncology specimens were tested. PRIM1 was found to be amplified in 41% of the samples. PRIM1 is coamplified with the core 12q13 amplicon genes CDK4, SAS, and OS9, and was physically mapped very close to them. PRIM1 is therefore a new candidate for the role of a major target gene of 12q13 amplifications in human cancers. Genes Chromosomes Cancer 26:62-69, 1999.

Blotting, Northern↗
PubMed1999

Scanning electron microscopic analysis of diseased and healthy dental hard tissues after Er:YAG laser irradiation: in vitro study.

The aim of this study was to treat carious lesions, sound dentin, and enamel either with conventional methods or with an Er:YAG laser and to compare the results. Thirty freshly extracted carious human teeth were divided into two groups. In the first group, lesions were treated with burs in a dental handpiece; in the second group, we used the Er:YAG laser with parameters recommended by the manufacturer (Kavo). After treatment, the teeth were prepared for scanning electron microscopic observation. On laser-treated teeth, scaly, flaky, rough surfaces were seen: surfaces were clean with several morphological reliefs that may enhance bonding resin restoration. The Er:YAG laser beam can ablate carious dentin with an energy level of 250 mJ at 2 Hz. Sound dentin can be cut at 300 mJ and 2 Hz; for enamel, 350 mJ and 3 Hz are required. The Er:YAG laser seems to be effective in the treatment of carious lesions and in cavity preparation in vitro.

Dental Caries↗
PubMed1997

In-vivo activity and tolerance of conventional formulation versus fat emulsion formulation of amphotericin B in experimental disseminated candidiasis in neutropenic rabbits.

Amphotericin B can cause significant toxicity but this can be reduced by direct dilution into a fat emulsion (Intralipid). To investigate the potential use of amphotericin B diluted in Intralipid, a study was made of its activity in the treatment of subacute disseminated candidiasis in persistently granulocytopenic rabbits, compared with the same dose of amphotericin B diluted in dextrose. Amphotericin-B-fat emulsion was at least as effective as amphotericin-B-dextrose. Amphotericin-B-fat emulsion was significantly more effective than amphotericin-B-dextrose therapy in reducing candida colony counts in both kidney and liver tissues (P < 0.05). Furthermore, amphotericin-B-fat emulsion was found less toxic on the renal function than conventional amphotericin B (P < 0.05). From these experimental results, we conclude that amphotericin-B-fat emulsion (Intralipid) was at least as effective and less toxic than conventional amphotericin B.

Amphotericin B↗
PubMed1991

Scanning electron microscopic study of odontoblasts and circumpulpal dentin in a human tooth.

Two combined scanning electron microscopic methods including modified fixative procedures were used for studying the morphologic aspects of the odontoblasts and the corresponding dentinal wall at different endodontic levels. The odontoblasts were tightly packed in the pulp horn, where they assumed pear-shaped profiles and, from crown to apex, successively looked spindle shaped, club shaped, and globular. Their number decreased in the pulp radicular portion, where the interglobular spaces were enlarged. The filling fibrillar material varied from crown to apex. A globular circumpulpal dentin was observed at all levels of the root canal. The tubule openings varied in number and size.

Adult↗