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Biomedical subjects

A Petrou

Publications and source records attributed to A Petrou.

At least 37 records · Page 2Linked to original sources
PubMed1995

Somatostatin and total intravenous anaesthesia. Assessment of analgesic requirements during surgery and the effects on liver enzymes.

We have studied the analgesic effects of somatostatin during surgery and its influence on the plasma glucose levels and the liver enzyme profile in 40 ASA 1 or 2 patients undergoing surgery for carcinoma of the gastrointestinal tract. Each patient received either somatostatin bolus 3.5 micrograms.kg-1 intravenously plus an infusion of somatostatin 3.5 micrograms.kg-1.h-1, or sodium chloride 0.9% as a placebo in a double-blind manner. Anaesthesia was induced with propofol 1 mg.kg-1 followed by a continuous infusion of propofol in a stepwise declining regimen. Vecuronium was used for muscular relaxation. Fentanyl 100 micrograms was administered intravenously in bolus doses for analgesia during surgery as required. Blood samples were taken at 10 min pre-induction, 5 min postintubation, 5, 30, 60, 120 min postincision and 30 min post-recovery for plasma glucose levels. Blood samples were also taken at 10 min pre-induction, 120 min postincision and 24 h postoperatively for liver enzymes. The total requirement for fentanyl in the control group was significantly higher (p < 0.001) than in the group that received somatostatin. Eight out of 20 patients in the study group required no additional analgesia intra-operatively. The changes in blood glucose values followed the same pattern in both groups. There was a tendency for liver enzymes to increase in both groups. Although this increase was less in the study group, this change was not statistically significant.

Adult↗
PubMed1991

Argon laser initiated resin photopolymerization for the filling of root canals in human teeth.

This work was undertaken to determine if 488 nm light is transmitted through dentin in quantities adequate to polmerize resin located several milimeters from the light source (an optical fiber). The spread of polymerization in a camphorquinone activated resin due to 488 nm light emanating from an opaque plastic canal was compared with light emanating from a canal of the same diameter in tooth dentin. Results indicated that irradiation of a resin-filled chamber via an opaque canal generated a series of ellipsoidal forms, while irradiation via a root canal generated bullet-shaped forms of much larger volume and weight. The base of these bullet-shaped forms was flat against the dentin-resin interface and surrounded the canal. These results indicated that 488 nm argon laser light was transmitted through dentin and could act to polymerize resin at a distance of several millimeters from the canal. Further experiments verified that resin in lateral canals of tooth roots was readily polymerized by 488 nm light applied at low power levels (50 mW). These experiments demonstrate the effectiveness of the argon laser in polymerizing light activated dental resins located within or adjacent to tooth dentin at distances up to several milimeters from the fiberoptic terminus. The flexibility and control that these procedures make possible in the obturation of root canals may lead to substantial improvements in endodontic therapy.

Dental Restoration, Permanent↗
PubMed1990

Laser photopolymerization of dental materials with potential endodontic applications.

Photopolymerizing resins were exposed to three different wavelengths of light emanating from the argon laser. It was determined that the most efficient wavelengths for photopolymerization of camphorquinone-activated resins were at 477 and 488 nm. The 514.5-nm wavelength was relatively ineffective in activating polymerization. Four camphorquinone-activated resins were placed in the root canals of teeth and tested for polymerization depth using a 488-nm wavelength laser beam coupled to an optical fiber 200 microns in diameter. In regard to polymerization depth, these materials ranked as follows: Genesis greater than Prisma-Fil greater than Prisma Microfine greater than Prisma VLC Dycal. Alterations in the positions of the optical fiber and the surface of the resin in the canal made only minor differences in polymerization depth of the samples. The results indicate that an argon laser coupled to an optical fiber could become a useful modality in endodontic therapy.

Argon↗
PubMed1990

Postoperative recurrence of splenic epithelial cyst; treatment with subtotal splenectomy.

Three children were operated upon for congenital epithelial cysts of the spleen in the five-year period 1983-1987. Their mean age was 9.8 +/- 2.3 years. Two of them were boys. They comprise 1.6% of the surgical pathology of the spleen in our hospital, which is a Reference Centre for congenital haemolytic diseases. Two of the children had been suffering from intermittent colic pain in the left hypochondrium with a tender palpable mass for a short while to the present day. The third patient was asymptomatic; a splenic cyst with calcification of its wall was accidentally revealed by a plain x-ray of the abdomen. Contrast gastrointestinal studies and intravenous pyelography helped us with the diagnosis; they indicated a splenic mass that caused visceral displacement adjacent to the spleen. Ultrasonography proved the cystic nature of the enlargement of the spleen in all the cases. Marsupialization was performed in one patient and removal of the cysts in the other two. All three patients were followed up and re-checked 1-5 years postoperatively (May-June 1988). In one boy who underwent removal of the cyst four years ago, recurrence of the splenic cyst was revealed by ultrasonography, CT scan and radionuclide scan. Subtotal splenectomy was performed. The remaining upper pole is supplied with blood by the short gastric arteries. The recurrence was attributed to coexistence of invisible tiny cysts that had remained in the splenic tissue after the dissection of the major cyst during the previous operation. Subtotal splenectomy is an acceptable alternative procedure for splenic cysts.

Adolescent↗