[Evaluating the morphology of uncertain breast tumors using color coded Doppler ultrasound]. / Dignitätseinschätzung unklarer Mammatumoren mit Hilfe der farbkodierten Dopplersonographie.

AIM: The relationship between tumour vessel density and tumour vitality in breast carcinoma has been well established in histopathological studies. Our objective was to find out if colour-coded sonography is helpful in the evaluation of suspicious breast masses. METHOD: 106 patients were studied; in all cases a biopsy was obtained. Peripheral and central blood vessels in a lesion were counted and peak systolic velocities (PSV) were measured as well as the resistive index (RI). The grade of vascularisation was scored on a scale from I-IV indicating an increasing vessel count and increasing PSV. RESULTS: 83% of the carcinoma (n = 61) and 45% of the benign lesions (n = 45) showed vascularity grade III or IV (hypervascularity). The mean PSV of all carcinomas was 0.23 m/s, in benign lesions 0.14 m/s (p < 0.005). Although G3 carcinomas showed higher vascularisation than G2 carcinomas, the difference was not statistically significant. T3 + 4 tumours had significantly higher PSV than T1 + 2 carcinomas (p < 0.01). In 12 of 23 cases with unclear morphology in the B-mode, the additional finding of hypervascularity led to the misinterpretation of a benign lesion as a carcinoma. CONCLUSION: Although increased vascularity correlated with degree of malignancy the finding of hypervascularity did not help to distinguish a benign from a malignant lesion in individual cases. Consequently, it did not help to reduce the biopsy rate. In benign lesions with hypervascularity and borderline morphology, the risk of a false positive diagnosis is high.

Disposition and uric acid lowering effect of oxipurinol: comparison of different oxipurinol formulations and allopurinol in healthy individuals.

We have investigated the disposition and plasma uric acid lowering effect of oxipurinol in ten healthy individuals following oral administration of three different formulations of oxipurinol and of allopurinol in equimolar doses. The reduction of plasma uric acid was clearcut up to 48 h. As estimated from plasma AUC0-infinity, Cmax, tmax, tlag, and urinary drug excretion, a conventional rapid release preparation of oxipurinol sodium was clearly superior to oxipurinol as free acid and to enteric coated microtablets of oxipurinol sodium. Plasma oxipurinol concentrations following a single dose of the conventional formulation of oxipurinol sodium were approximately 25% lower than those observed after an equimolar dose (300 mg) of allopurinol, but mean Cmax reached the value reported to be necessary for 90% inhibition of xanthine oxidase. Since prolonged administration will result in accumulation of oxipurinol because of its slow elimination, this type of oxipurinol formulation can be expected to meet the therapeutic requirements for a drug to lower plasma uric acid.

Simultaneous determination of allopurinol and oxipurinol in human plasma and urine by high-performance liquid chromatography.

The uricostatic drug allopurinol (CAS 315-30-0) is used for treatment of hyperuricaemia and is mainly bio-transformed to the active metabolite oxipurinol (CAS 2465-59-0) in humans. A new assay was developed for the simultaneous determination of both compounds in plasma and urine using ultrafiltration and ion exchange purification steps for plasma and urine, respectively. Reversed-phase high-performance liquid chromatography with ultraviolet detection was applied for the separation and quantitation of both compounds. The limit of detection was 0.1 microgram/ml for both compounds in plasma and 0.2 and 0.5 microgram/ml for allopurinol and oxipurinol, respectively, in urine. Within-run and day-to-day precision of 3-5% and 5-7% was determined for plasma and 6-8% and 8-10% for urine analysis. The assays were further validated using liquid chromatography with photodiode array detection and by comparison with methods using protein precipitation as the purifying step. The high analytical recoveries, selectivity, sensitivity, accuracy and reproducibility were adequate for the measurement of both compounds in pharmacokinetic studies and for drug monitoring in patients on allopurinol therapy.

[The MRT criteria for the differentiation of "pseudotumorous" lesions from bone sarcomas of the extremities]. / MRT-Kriterien zur Differenzierung "pseudotumoröser" Läsionen von Knochensarkomen der Extremitäten.

The MRT scans of 57 patients with Ewing or osteosarcomas and 34 patients with haematogenous osteomyelitis or periostitis/stress fractures were examined in order to determine whether a distinction between benign or malignant lesions is possible. Four criteria were evaluated: the margin of the bone marrow component; intensity and homogeneity of the T1 weighted signal in the bone marrow; presence of an extraosseous structured soft tissue mass and/or soft tissue edema. It was found that central osteosarcomas and Ewing's sarcomas reduced signal intensity of the marrow to become muscle-isointense with a well-defined margin. In acute haematogenous osteomyelitis and periostitis/stress fracture the marrow lesion was not sharply demarcated. In contrast to patients with bone sarcomas, only one case of osteomyelitis showed an extraosseous structured soft tissue mass. On the basis of these findings we believe that acute haematogenous osteomyelitis can be distinguished with high degree of accuracy from Ewing's sarcoma and central osteosarcomas.