Extracellular-signal regulated kinase regulates production of pro-opiomelanocortin in pituitary melanotroph cells.

The extracellular signal-regulated kinase (ERK) pathway is important in the regulation of neuronal plasticity, although a role for the kinase in regulating plasticity of neuroendocrine systems has not been examined. The melanotroph cells in the pars intermedia of pituitary gland of the amphibian Xenopus laevis are highly plastic, undergoing very strong growth to support the high biosynthetic and secretory activity involving α-melanophore-stimulating hormone (α-MSH), a peptide that causes pigment dispersion in dermal melanophores during the adaptation of the animal to a dark background. In the present study, we tested our hypothesis that ERK-signalling is involved in the regulation of melanotroph cell function during black-background adaptation, namely in the production of pro-opiomelanocortin (POMC), the precursor of α-MSH. Using western blot analyses, we found elevated levels of the activated (phosphorylated) form of ERK in melanotrophs of black- versus white-adapted animals. Treatment of melanotrophs in vitro with the mitogen-activated protein kinase kinase inhibitor U0126 markedly reduced ERK phosphorylation and lowered the transcription as well as the translation of POMC. This same treatment also reduced the expression of BDNF transcript IV and of the immediate early genes c-Fos and Nur77. We conclude that ERK-mediated signalling is important for the maintenance of the melanotroph cells in an active state.

Antibiotic concentrations in the groin wound after vascular prosthetic implantation.

The kinetics of systemically and locally administered cefuroxime or ceftazidime in wound fluid were investigated in the period after vascular prosthetic implantation. Cefuroxime or ceftazidime was administered intravenously in patients. Simultaneously 250 mg ceftazidime or cefuroxime was added to preclotted blood. Locally administered antibiotics could not be detected in our samples. In groin fluid samples 24-48 h after the operation the average concentration of cefuroxime was 8.3 and of ceftazidime 5.0 mg/l. The decline of the concentration of cefuroxime or ceftazidime in groin fluid seems to be much slower than one would expect from the half-lives of the antibiotics. We conclude that cefuroxime and to a lesser extent ceftazidime are suitable as prophylactic agents in arterial reconstruction.

The correlation of peroperative outflow resistance measurements with patency 109 infrainguinal arterial reconstructions.

The predictive value of outflow resistance measurements for the patency of femoro-popliteal and femoro-crural bypass grafts was analysed. Peroperative outflow resistance measurements were performed in 109 infrainguinal arterial reconstructions. Outflow resistance was significantly higher in occluded bypasses compared with those which remained open (P less than 0.01), but there was a considerable overlap of values in both groups. Statistical analysis of the correlation between outflow resistance and patency rates at 3 months revealed a marginal correlation in the femoro-popliteal bypass group (R = -0.25), which was not significant (P = 0.064). In the femorocrural bypass group there was again only a marginal correlation (R = -0.27) but this was statistically significant (P = 0.05). These data demonstrate that intraoperative outflow resistance measurements are only of limited value for predicting bypass patency in individual cases.

Treatment of complicated or infected pilonidal sinus disease by local application of phenol.

This article reports on the results of conservative treatment of 48 patients with complicated pilonidal sinus disease. The treatment consisted of an injection of phenol 80% into the sinus tract after the patients had undergone depilation and excavation while under local anesthesia. The number of phenol injections in each patient varied from one to nine (mean: two injections). Patients were considered cured if no signs of recurrent pilonidal sinus disease occurred within 1 year after treatment. The mean follow-up period after cure was 3 years (range: 1 to 6 years). The recurrence rate was 6.3% (a 95% confidence interval of 1.3% to 17.2%), which was one of the lowest reported for different methods of treatment for pilonidal sinus disease. The good results in this study justify continuation of conservative treatment of pilonidal sinus disease, especially in view of the low costs and the high degree of patient comfort. Sclerosing therapy with phenol is thus recommended as a successful treatment for complicated pilonidal sinus disease.

Tracheal reconstruction with hydroxyapatite tracheal prosthesis.

A porous hydroxyapatite tracheal prosthesis was implanted in rabbits after resection of a 15 mm circular segment of the cervical trachea. Postoperatively the animals were followed by radiography, bronchoscopy, and microscopy at the time of autopsy. The longest survival time was 22 weeks. All the rabbits died of infection at the prosthetic site or of progressive stenosis at the anastomoses. The prosthesis was incorporated by surrounding tissues, but no overgrowth of ciliated epithelium on the luminal surface of the prosthesis was observed. Although a hydroxyapatite tracheal prosthesis is tolerated in rabbits, covering of the luminal surface of the prosthesis with a non-porous layer to prevent infection and to permit mucosal overgrowth is necessary to achieve better long-term results.

Service station attendants' exposure to benzene and gasoline vapors.

Service station attendants' exposure to benzene, based on 85 TWA results at 7 stations, were well below 1 ppm except one exposure of 2.08 ppm. Short term exposures were 1.21 ppm or less over 15 minutes. Attendants' TWA exposures to total gasoline vapor were 114 ppm or less, with measured 15 minute exposures no higher than 100 ppm during actual filling operations. One station had vapor recovery nozzles; exposures here were below the detectable level (0.01 ppm benzene) on 10% more days than the next lowest station. Still, the magnitude of overall exposures and the degree of reduction indicate that vapor recovery is not needed to control exposures. Some attendants had consistently higher exposures than others. This is felt to be due to work practices, such as standing close to the fill opening, plus local wind conditions around the car as it is filled with gasoline.