Negative argininosuccinate synthetase expression in melanoma tumours may predict clinical benefit from arginine-depleting therapy with pegylated arginine deiminase.

BACKGROUND: Arginine-depleting therapy with pegylated arginine deiminase (ADI-PEG20) was reported to have activity in advanced melanoma in early phase I-II trial, and clinical trials are currently underway in other cancers. However, the optimal patient population who benefit from this treatment is unknown. METHODS: Advanced melanoma patients with accessible tumours had biopsy performed before the start of treatment with ADI-PEG20 and at the time of progression or relapse when amenable to determine whether argininosuccinate synthetase (ASS) expression in tumour was predictive of response to ADI-PEG20. RESULTS: Twenty-seven of thirty-eight patients treated had melanoma tumours assessable for ASS staining before treatment. Clinical benefit rate (CBR) and longer time to progression were associated with negative expression of tumour ASS. Only 1 of 10 patients with ASS-positive tumours (ASS+) had stable disease, whereas 4 of 17 (24%) had partial response and 5 had stable disease, when ASS expression was negative (ASS-), giving CBR rates of 52.9 vs 10%, P=0.041. Two responding patients with negative ASS expression before therapy had rebiopsy after tumour progression and the ASS expression became positive. The survival of ASS- patients receiving at least four doses at 320 IU m(-2) was significantly better than the ASS+ group at 26.5 vs 8.5 months, P=0.024. CONCLUSION: ADI-PEG20 is safe and the drug is only efficacious in melanoma patients whose tumour has negative ASS expression. Argininosuccinate synthetase tumour positivity is associated with drug resistance and tumour progression.

Dosimetric and chemical characteristics of Fricke gels based on PVA matrices cross-linked with glutaraldehyde.

Fricke gel radiochemical sensors based on various matrices have been studied for decades as 3D dosimeters for radiotherapy. Despite their many appealing features, progressive aging and blurring of the signal have prevented the widespread use of these dosimeters, so far. We have addressed these shortcomings and hereby present our development of a Fricke gel based on a chemically cross-linked PVA matrix. We investigated the influence of several parameters of the polymeric matrix on sensitivity, diffusion coefficient and spontaneous oxidation of the proposed gel dosimeter. Based on these findings, we optimized the gel compositions. Our new gel formulation combines transparency, high sensitivity and simple production method, typical of gels based on natural polymers, with low diffusion coefficient and slow spontaneous oxidation typical of PVA gels made by freezing-thawing.

[A diagnostic protocol in cherubism]. / Protocollo diagnostico del cherubismo.

Cherubism is a rare hereditary maxillo-facial pathology with unknown pathogenesis. The purpose of the present study is to describe a correct diagnostic approach to cherubism, especially for the differential diagnosis with other maxillo-mandibular cystic diseases. Therefore, the typical clinical, radiological, genetical and histopathological aspects of this pathology are examined. Moreover, an adequate therapy for the cases examined in this study is suggested.

[Study on the antihemorrhagic action of aminaphtone]. / Studio sull'azione antiemorragica dell'Aminaftone.

This research is the continuation of a previous published paper. The blood losses occurring during multiple dental extractions under general anesthesia in pretreated patients (not with a recent new capillary protector) have been measured. The results obtained have been processed statistically and confirm the effectiveness of the product.

Duplex Doppler ultrasound study of the temporomandibular joint.

INTRODUCTION: The anatomy and physiology of the temporomandibular joint can be studied clinically and by diagnostic imaging. Magnetic resonance imaging (MRI), radiography (X-ray) and computed tomography (CT) have thus for many years contributed to the study of the kinetics in the mandibular condyle. However, also duplex Doppler ultrasound (US) examination is widely used in the study of structures during movement, particularly vascular structures. MATERIALS AND METHODS: A total of 30 patients were referred by the Department of Orthodontics to the Department of Radiological, Oncological and Pathological Sciences, University of Rome "La Sapienza". All patients underwent duplex Doppler ultrasound (US) examination of the temporomandibular joint using Toshiba APLIO SSA-770A equipment and duplex Doppler multi-display technique, which allows simultaneous display of US images and color Doppler signals. A linear phased array probe with crystal elements was used operating at a basic frequency of 6 MHz during pulsed Doppler spectral analysis and 7.5 MHz during US imaging. RESULTS: In normal patients a regular alternation in the spectral Doppler waveforms was obtained, while in patients with temporomandibular joint meniscus dysfunction there was no regularity in the sum of the Fourier series with an unsteady waveform pattern related to irregular movements of the temporomandibular joint. CONCLUSIONS: In all cases duplex Doppler US examination proved able to differentiate between normal and pathological patients and among the latter this technique permitted identification of the most significant aspects of the dysfunctional diseases.

Hemodialysis with regenerated cellulosic membranes does not reduce plasma selenium levels in chronic uremic patients.

Selenium (Se) is considered an essential and very important trace element for humans. Se blood levels are frequently low in end-stage renal disease (ESRD) patients, but very little has been established concerning the mechanisms that could modify Se status in uremia, including a supposed dialysis-mediated Se depletion. In order to verify whether hemodialysis (HD) can induce a loss of Se, thereby leading or contributing to a low plasma Se concentration, we investigated the effect of HD procedure with the most commonly used regenerated cellulosic membrane (Cuprophan) on plasma Se levels in 20 uremic patients on HD for 62.5 +/- 49.4 months. Plasma Se levels were also determined in 15 chronic renal failure (CRF) nondialyzed patients and in 28 age-matched healthy controls. Se concentration was determined by atomic absorption spectrophotometry. Plasma Se levels of both HD patients (61.3 +/- 8.5 micrograms/L) and CRF nondialyzed patients (56.4 +/- 10.1 micrograms/L) were significantly lower than in normal subjects (78.3 +/- 9.7 micrograms/L, p < 0.001). In CRF nondialyzed patients, a significant (p < 0.05) negative correlation was found between the plasma Se concentration versus serum creatinine values. Within the HD group, plasma Se levels significantly increased after the HD procedure (72.8 +/- 17.2 micrograms/L, p < 0.02) together with hematocrit and total plasma protein values (p < 0.05 and p < 0.001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)