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Biomedical subjects

G Chiarelli

Publications and source records attributed to G Chiarelli.

168 records · Page 10Linked to original sources

Salvage insertion of tunneled central venous catheters in the internal jugular vein after accidental catheter removal.

PURPOSE: Tunneled catheters are widely used for intermediate to long-term hemodialysis (HD) access, but are prone to several complications that can require catheter replacement. Replacing malfunctioning catheters with a new line, placed in a different access site, can lead to problems with multiple vein occlusions. This has led many nephrologists to continue using the same vein as long as possible by guidewire catheter exchanges, to preserve other veins for future use. We describe a guidewire exchange technique for the Ash-Split catheter in the internal jugular vein. METHODS: In three patients, the exchange was performed because of partial catheter removal, as evidenced by the outward dislocation of the Dacron cuff. In these patients, the guidewire was inserted through the catheter. In two additional patients, the catheter had been completely removed by accident: the replacement of the dislodged tunneled venous catheters was attempted 5 hr and 1 day after accidental removal. In these patients, the guidewire was inserted through the previous tunnel. After guidewire placement, a skin incision was made in the supraclavicular region. The metal guidewire was easily located inside the fibrous structure that had previously surrounded the catheter. The guidewire was then extracted from the subcutaneous tunnel and used to insert a new catheter safely and easily after creating a new tunnel. Patients were routinely given antibiotic prophylaxis (1 g of cefazolin) immediately before the procedure. A strict aseptic technique was used, including several sterile glove changes. RESULTS: No infections developed following this procedure, which has the potential for bacterial contamination. All procedures were successful. Only in one patient did we have to convert to a different catheter: it was not possible to replace the old Ash-Split catheter with the same dual-lumen catheter because of difficulties in inserting the peel away introducer-catheter complex. In this patient, rather than forcing it with larger dilators or trying to disrupt the fibrin sheath with balloon dilatation, a single lumen Tesio catheter was successfully placed. In both patients who completely lost the previous catheter, the guidewire was readily reinserted through the subcutaneous tunnel into the vein. Catheter function was excellent in all patients, with a test blood flow rate on the 1st catheter use >350 ml/min. CONCLUSIONS: We described a new method for catheter exchange, which allows the easy insertion of a new catheter and the creation of a new and safer subcutaneous tunnel. In addition, we demonstrated that in cases of complete catheter removal, it is possible to reinsert a catheter in the same vein through a guidewire, even when reinsertion was attempted up to 1 day later.

Journal Article↗

[Role of beta-carotene in the prevention of genotoxic damage in patients undergoing radiotherapy. Monitoring by the micronucleus test in exfoliative cells of the oral cavity].

Radiotherapic treatment of patients with carcinoma usually causes genotoxis damage. This has been studied recently using the test of micronuclei in esfoliated cells. This test presents methodologic advantages in compared with the classic citogenetic analysis and as it is carried out on esfolieted cells from the oral cavity it faithfully reflects the genotoxic damage undergone by the cells of the basal layer of the epitelium. The preliminary result obtained so far have confirmed the anticlastogenic activity of beta-carotene in fact, the frequence of micronuclei in esfolieted cells from the oral cavity in patients undergoing radiotherapy or undergoing treatment with beta-carotene is inferior to that of patients undergoing treatment with beta-carotene is inferior to that of patients undergoing radiotherapy without the subministration of carotenoids. Treatment with carotenoids does not influence the therapeutic efficiency of radiotherapy treatment. Therefore, the results seem to confirm that indirect ossidaction processes are involved in the mechanism of the clastogenic action of radiotherapia. The carotenoids seem to be able to contrast validly this undesirable effect without interfering with the desirable therapeutic effect.

Antimutagenic Agents↗

[New insights in the pathogenesis of secondary hyperparathyroidism].

Parathyroid gland growth is a major cause of secondary hyperparathyroidism in renal failure. It is well known that high serum phosphate levels, low serum calcium levels and vitamin D deficiency are the three promoters of parathyroid hyperplasia in renal failure. Recent studies have investigated in depth the potential role of growth factors (transforming growth factor alpha) and their receptors (epidermal growth factor receptor) in the pathogenesis of parathyroid cell hyperplasia in chronic renal failure. The identification of molecular mechanisms involved in calcium, phosphate and vitamin D manipulations in an experimental renal failure model could help design more effective therapy for secondary hyperparathyroidism in uremic patients.

Calcium↗