Hyperparathyroidism (HPT) is common in patients on dialysis, and parathyroidectomy (PTx) is often required. We present a retrospective, descriptive analysis of data corresponding to 148 patients on dialysis undergoing PTx due to severe refractory HPT (PTH 1401 +/- 497 pg/mL, Ca 10.6 +/- 0.8 mg/dL, P 6.9 +/- 1.7 mg/dL). Demographic data were compared with those recorded in 309 patients on dialysis not subjected to PTx who were managed at the same hospital. In the PTx group, the factors age (49.3 +/- 14 years), male gender (48.6%), and diabetes (0.7%) were significantly lower than in the non-PTx group (61.5 +/- 14.9 years, male gender 59%, diabetes 19.4%), while time on dialysis was longer (8.6 +/- 5.8 vs. 5.5 +/- 5.4 years). In 129 of the study patients (87.4%), four or more glands were identified, and total PTx plus autotransplantation (AT) in the forearm was performed. In the remaining 19 patients, two to three glands were identified, and AT was not undertaken. Four of the 19 patients were successfully operated on again for persistent HPT, seven showed PTH levels <250 pg/mL, and eight maintained severe HPT. Perioperative complications included one death due to cardiac insufficiency, two repeat operations due to bleeding, and one patient with chronic hoarseness. Hospital stay was prolonged in 20% of patients due to a hungry bone syndrome. Among those patients with PTx and AT, HPT recurred in 21 patients (16.2%) at 3.1 +/- 2.3 years. In 13 of these patients, autograft was removed at 7.5 +/- 2.9 years. Serum calcium and phosphate levels improved after PTx, and these results were maintained for 5 years (9.6 +/- 0.8 and 4.2 +/- 1.2 mg/dL, respectively). In conclusion, PTx with AT is a safe option for the treatment of severe HPT that is accompanied by low morbidity and mortality and a good outcome. Medical treatment should not be prolonged at the expense of long repeated bouts of hypercalcemia and/or hyperphosphatemia with their irreversible consequences.

Using an interactive software program, Virtual Chemistry Laboratory (VCL), we conducted an educational experiment to assess the software's influence on student understanding of some basic organic chemistry laboratory techniques. First-year engineering students at the Superior Polytechnic School of Córdoba were evaluated: more favorable results were obtained from students who had worked with the VCL when compared to results of students who had not worked with the VCL. We conclude that the use of VCL helps students gain a better understanding of the techniques and basic concepts used in the laboratory work. Use of the program particularly contributes towards improving the progress of those students with the greatest learning difficulties.

One hundred and one surgical procedures performed in children for construction and maintenance of vascular accesses for haemodialysis were retrospectively analyzed. There were 86 operations performed to create a new fistula in patients without vascular access or with nonrecoverable failed angio-access. Fifteen surgical procedures were performed to treat fistula complications. The new fistulas were radiocephalic n = 60 (70%), ulnar-basilic n = 5 (5.8%), antecubital n = 9 (10.3%), and PTFE grafts n = 12 (14%). Microsurgical techniques were used in all cases, including PTFE graft fistulas. A microscope was used in 56 cases (55.4%) and magnifying loupes (x 2.5 magnification) in the rest of the operations. Early-failure rate for radiocephalic fistulas was 10%. Cumulative patency rates in radiocephalic fistulas were 79%, 75%, and 70% at 1, 2, and 5 years, respectively. No statistical differences were found from the cumulative patency curve of 730 radial-cephalic fistulas performed in adults during the same period of time. Radiocephalic fistulas can be constructed in most paediatric cases using microsurgical technique. Elbow fistulas can be the second-choice vascular access, and PTFE grafts can be reserved for children with exhaustion of autologous veins. Brachial-jugular PTFE grafts can be used in cases of subclavian vein stenosis.

The purpose of this retrospective study was to analyze 2 sizes of expanded polytetrafluoroethylene (PTFE) upper arm grafts for dialysis: 8 millimeters, tapered to 6 mm at the arterial side, and 6 millimeters. All upper arm PTFE grafts (Gore-Tex(R)) were performed between January 1981 and April 1997. Patient characteristics, complication rate, and patency rates were compared for both kind of grafts. Five hundred and seven PTFE grafts were analyzed (183 6-mm grafts and 324 6- to 8-mm grafts). Early failure was found in 5 grafts (2.7%) in 6-mm grafts, and in 5 grafts (1.5%) in 8-mm grafts (not significant). Steal syndrome was found in 1 patient (0.5%) of the 6-mm group, and in 11 (3.4%) of the 8-mm grafts (p=0.085). The rate of late complications requiring surgical repair was 0.56 episode per graft-year in the 6-mm grafts group, and 0.33 in the 8-mm grafts (p<0.001). Primary patency rates of 6-mm grafts were 72%, 33%, and 19% at 1, 3, and 5 years; and secondary patency rates were 86%, 68%, 56%, and 44% at 1, 3, 5, and 6 years, respectively. In the 8-mm grafts group, primary patency rates were 77%, 52%, and 39% at 1, 3, and 5 years; and secondary patency rates were 92%, 84%, 73%, and 66% at 1, 3, 5, and 6 years, respectively. Comparison of patency rates of 6-mm and 8-mm grafts were statistically significant (p<0.001) for both primary and secondary curves. However, secondary survival curves were similar for both kind of grafts in a subpopulation of diabetic patients. The authors conclude that the 8-mm graft, tapered to 6 mm at the arterial side, is a dialysis graft with fewer complications and a better patency rate than grafts of 6 mm placed in the same anatomical position, at least in a population of nondiabetic patients. Steal syndrome was observed in some cases of diabetic and older patients with a large-bore graft. Thus, this kind of prosthesis should be avoided in this population. On the other hand, this is not a prospective, randomized study made with any intention for comparison. Therefore, the aforementioned conclusions must be cautiously considered.

Eight millimeter expanded polytetrafluoroethylene (e-PTFE) grafts, tapered to 6 mm at the arterial site, are used by our group in the upper arm in order to avoid midgraft stenosis observed with other graft sizes. Long-term results (1-12 years) on 157 6-8 mm brachioaxillary e-PTFE grafts (Gore-Tex) are analyzed. Early failure was found in 4 grafts (2.5%). The rate of late complications was 0.37 episodes per graft-year. Steal syndrome, found in 4 cases (2.5%), was successfully treated in 3 cases by graft banding. Neither midgraft nor arterial anastomotic stenosis was observed in the 63 grafts requiring surgical thrombectomy or fistulography. The primary patency rates were 73%, 53%, and 41% at 1, 3, and 5 years, respectively. The secondary patency rates were 91%, 80%, and 72% at 1, 3, and 5 years, respectively. Comparison between both curves by the log rank test was significant (p < 0.001) expressing the efficiency of rescue surgery. We conclude that a 6-8 mm graft can be successfully used for dialysis in the brachioaxillary position.