Aging of silastic peritoneal catheters.

Increasing the survival of patients on CAPD is related to the long-term reliability of the peritoneal access. Six silicone Tenckhoff catheters (with strip or diffuse barium sulphate inclusion) removed after 39-69 months because of the appearance of external segment fissures, were analysed by scanning electron microscopy (SEM) and infra-red spectroscopy with attenuated total refractance (ATR). The extracorporeal portion of the catheters showed (by ATR) a more prominent oxidation peak on the external than the internal surface; SEM showed marks and cracks on the external surface and exfoliation and flattening of the silastic reticle on the intraluminal surface. No evidence of oxidation was found in the intra-abdominal portion of the catheters but biofilm was found. We suggest that barium sulphate may render the silastic brittle and physiological and environmental long-term factors (such as uv-rays, temperature, sweat and disinfectants) could cause oxidation and loss of physico-chemical properties, with critical aging of the silastic and loss of catheter resistance to mechanical injury.

[Pulp necrosis following prosthetic-periodontal treatment of vital teeth]. / Necrosi pulpare conseguente a trattamenti protesicoparodontali in denti vitali.

This study investigated the frequency of periapical lesions following pulpal necrosis in vital teeth used as abutments in periodontal-prosthetic therapy. The study was conducted on a continuative series of 1000 teeth treated at least 2 years before the start of the investigation. 500 teeth were treated by specialist and 500 by general practitioners. The dental records of this sample were stored into a computer, analyzed and compared, and the chi-square index was calculated. Periapical lesions were found in 22.6% of the teeth. Maxillary incisors had the highest number of lesions (36.8%). The percentage of lesions increased as periodontal involvement became more severe (37.2%) with severe involvement as opposed to 18.5% with moderate involvement). The frequency of lesions was lower in the group of teeth treated by specialists than in the group treated by general practitioners (13.8% as opposed to 31.4%).

[Bacampicillin in dentistry. Clinical efficacy and tolerance]. / La bacampicillina in odontostomatologia. Efficacia clinica e tolleranza.

The efficacy and tolerability of the Bacampicillin was evaluated on 80 patients (40 males and 40 females) with infectious pathology. This antibiotic was delivered at different dosage, alone or in association with Fans. The Authors report the statistical results showing the good therapeutical activity, at full dosage, with minor side effects.

Dextran deposits in tissues of patients undergoing haemodialysis.

Recently the possible storage of dextran-related material in patients undergoing regular haemodialysis has been suggested. We examined biopsy and autopsy specimens of 32 patients treated with regular haemodialysis for 61 +/- 34 months. All patients received dextran-40 as a plasma expander because of hypotension during haemodialysis. The same study was carried out in a control group of 11 haemodialysed patients who were given other plasma expanders. In the 11 patients who received larger doses of dextran-40 (0.38 g/kg body weight per week) we found particles in the cytoplasm of macrophages in various organs, which proved PAS positive and diastase resistant on light microscopy, and birefringent on polarisation. Electron microscopy revealed a fibrillar structure, but ionic analysis by electronic sampler on scanning electron microscopy excluded the presence of silicon. No intracellular inclusions were observed in the control group, nor in the patients given dextran-40 in doses lower than 0.08 g/kg body weight per week. As we also found a linear relationship between the number of particles and the dextran-40 doses given, we hypothesise that the material demonstrated in the macrophages is a structurally modified dextran.