The radiocephalic arteriovenous fistula remains the method of choice for haemodialysis access. In order to assess their suitability for fistula formation, the radial arteries and cephalic veins were examined preoperatively by ultrasound colour flow scanner in conjunction with a pulse-generated run-off system. Intraoperative blood flow was measured after construction of the fistulae. Post-operative follow-up was performed at various intervals to monitor the development of the fistulae. Radial artery and cephalic vein diameter less than 1.6 mm was associated with early fistula failure. The intraoperative fistula blood flow did not correlate with the outcome of the operation probably due to vessel spasm from manipulation. However, blood flow velocities measured non-invasively 1 day after the operation were significantly lower in fistulae that failed early compared with those that were adequate for haemodialysis. Most of the increase in fistula diameter and blood flow occur within the first 2 weeks of surgery.

Histiocytic sarcoma (HS) is associated with a poor prognosis owing to the presence of metastasis at the time of diagnosis in most dogs. Improved outcome has been reported in several dogs with localized HS following local therapy, however, distant metastasis occurs in 70-91% of dogs suggesting that adjuvant systemic therapy is necessary. The purpose of this retrospective study was to describe clinical characteristics and outcome in dogs with localized HS treated with aggressive local therapy plus adjuvant CCNU chemotherapy. Data from 16 dogs were evaluated. The median disease-free interval was 243 days. Two dogs had local recurrence and eight dogs developed metastatic disease with a median time to relapse of 201 days in these 10 dogs. The median survival time for all 16 dogs was 568 days. These results support the recommendation for aggressive local therapy combined with adjuvant CCNU chemotherapy in dogs with localized HS.

Summary Tumour tissue oxygenation has been measured in man during carbogen breathing (95% 02, 5% C02) using a commercially available polarographic electrode system (Eppendorf P02 histograph). At least 200 tumour measurements in each of 17 patients with accessible tumours were taken before, and subsequently continuously after the commencement of carbogen breathing for periods of 10 to 30 min. In 12 out of 17 patients studied there was a significant increase in median tumour P02 during the first 10 min of carbogen breathing (range 9 to 1800%). There was an initial rapid increase in tumour P02 which was maintained until 8 to 12 min, but then decreased throughout the subsequent treatment period. Although there was a reduction in the proportion of point measurements < IO mmHg in 11 out of 13 patients, during carbogen breathing, measured points of < 2.5 mmHg were only eliminated in three out of 11 tumours. The time course has implications for the planning of clinical trials utilising radiotherapy with carbogen breathing.

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The time course and dose response of 600 mm3 subcutaneous RIF-1 tumours to pentoxifylline was measured in terms of relative tumour perfusion, assayed by 86Rb extraction, and pO2 distribution measured by the Eppendorf histograph. Both perfusion and pO2 distribution were maximally increased by 20 mg/kg pentoxifylline 15 min after administration, perfusion to 141 +/- 15% (2 SE) of control, and median pO2 from 3 to 15 mmHg, with the percentage of values < 2.5 mmHg falling from 44 +/- 8% to 22 +/- 7%. Fifteen minutes after administration the pO2 increases were linearly dose-dependent up to 20 mg/kg. Correlation coefficients for perfusion data with the percentages of low values were, for time course and dose response data respectively, 0.76 and 0.84 for median pO2, 0.84 and 0.97 for percentage < 2.5 mmHg and 0.81 and 0.87 for percentage < 10 mmHg. The data show good correlation between changes in perfusion and pO2 distribution parameters, with better correlation for percentage of low values than for median pO2.

This study is concerned with an assessment of the quality of the blood vessels used in the construction of radiocephalic arteriovenous fistulae for haemodialysis vascular access in 20 patients. Following non-invasive preoperative assessment of the cephalic vein by means of a colour Doppler scanner, input impedance was determined intraoperatively from blood flow and blood pressure measured about 2 cm downstream of the anastomosis. The patients were re-assessed 1 day and 2, 4, 6 and 12 weeks after surgery, and the diameter and the flow through the fistulae, the location of major branches, and the presence and severity of stenoses in the cephalic veins were determined non-invasively. Five fistulae failed within the 12 weeks period following surgery, mainly due to thrombosis. In a further 3 patients, the fistulae were patent but did not achieve an adequately high blood flow and dilate sufficiently for haemodialysis and were therefore considered to be essentially failed. The impedance moduli from 0 to 10 Hz as well as the average impedance modulus of successful fistulae were significantly lower than those of fistulae that subsequently failed. An attempt was made to locate the presence of reflection sites (i.e. stenoses and branches) from the minima in the impedance modulus spectra. Their locations were compared with those of the reflection sites detected by ultrasound 2 weeks after surgery. However, not all reflection sites detected 2 weeks after surgery were located by the impedance method. It is recommended that both preoperative examination and intraoperative haemodynamic measurements be made to improve the accuracy of the assessment.

The radiocephalic arteriovenous fistula remains the method of choice for haemodialysis access. In order to assess their suitability for fistula formation, the radial arteries and cephalic veins were examined preoperatively by ultrasound colour flow scanner in conjunction with a pulse-generated run-off system. Intraoperative blood flow was measured after construction of the fistulae. Post-operative follow-up was performed at various intervals to monitor the development of the fistulae. Radial artery and cephalic vein diameter less than 1.6 mm was associated with early fistula failure. The intraoperative fistula blood flow did not correlate with the outcome of the operation probably due to vessel spasm from manipulation. However, blood flow velocities measured non-invasively 1 day after the operation were significantly lower in fistulae that failed early compared with those that were adequate for haemodialysis. Most of the increase in fistula diameter and blood flow occur within the first 2 weeks of surgery.