A plausible mechanism of electron transfer between quinones in photosynthetic reaction centers.

The mechanism of long-range electron transfer between the primary and the secondary quinone of photosynthetic reaction centers has been investigated, with particular attention on the role of the iron-histidine bridge. Computations suggest that in such a system, where the molecular subunits are packed together by H-bonds, a mobile electron, injected on one end of the chain, can be carried to the other end by switching the positions of the H-bonded hydrogens. Energy estimates would suggest that the proposed mechanism is plausible and worthy of further experimental investigations.

[Role of echography in the diagnosis of urethral stenosis]. / Ruolo dell'ecografia nella diagnostica delle stenosi dell'uretra.

A recently developed ultrasonographic technique was described to evaluate the anterior urethra in 10 men suspected to have urethral stenoses. With the patient in frog leg position, during a perfusion of the urethra with saline through a catheter positioned at the beginning of the urethra, penile, transscrotal and transperineal scanning of the urethra was obtained. In all patients a diagnosis of urethral stenoses was made. After sonographic evaluation all patient underwent retrograde urethrogram and internal urethrotomy, that confirmed the diagnosis made by ultrasound. The urethral ultrasound provides valuable informations about the number, extent, position of the strictures and eventual scarring of the periurethral tissue. Urethral ultrasonography can be used as alternative imaging modality to the conventional radiological techniques.

[Echo-guided percutaneous treatment of renal cysts: aspiration vs continuous 24-hour drainage]. / Trattamento percutaneo ecoguidato delle cisti renali: aspirazione vs drenaggio continuo di 24 ore.

The results of 2 treatment options, percutaneous aspiration vs percutaneous aspiration and continuous drainage over 24 hours, in the management of simple renal cyst were compared. Thirteen patients were managed with aspiration alone (group 1) while 19 with aspiration and continuous drainage (group 2). Recurrence rate was 100% in group 1 and 73% in group 2 (p: n.s.). Therefore, we believe that the higher cost of continuous drainage are not justified.

[Renal peripelvic multicystic lymphangiectasia: is echographic diagnosis possible?]. / La linfangiectasia multicistica peripielica renale (LMPR): è possibile una diagnosi ecografica?

We describe the role of US, in the diagnosis of LMPR and in differentiating LMPR from other renal disease, such as hydronephrosis and parapelvic cysts. In 10 patients mild to moderate hydronephrosis showed at the US, bilateral in 8 cases, was not confirmed at IVP and CT scan evaluation. Instead, compression of the collecting system by multiple cysts arising from the renal sinus was revealed by CT scan in 8 cases and by IVP in 2. At the U.S. the profile of the calices appeared irregular, differing from the features of hydronephrosis; furthermore calices were adjacent each other, separated only by a thin membrane. All patients were asymptomatic. The examination of the cystic liquor and wall, obtained percutaneously or during surgical procedures, showed the lymphatic origin of them. We cannot provide definitive data regarding how to differentiate LMPR from hydronephrosis at U.S.. In asymptomatic patients the U.S. evidence of dilated calices with irregular profile and thin membrane separating each other, can strongly suggest the diagnosis of LMPR.

Flow cytometric analysis and motility response to laminin and fibronectin of four new metastatic variants of the human renal cell carcinoma line RC43.

Using subrenal capsule implantation (SRC) in nude mice we have isolated 4 new sublines (RC43MSP, MBO, MLI, MDI) from the human renal cell carcinoma line (HRCC) RC43. These sublines exhibit an enhanced metastatic ability and a faster doubling time after subcutaneous (SC) transplantation in vivo, when compared to the parental line. With the aim of a better characterization of these new sublines we have performed a flow cytometric analysis (FA) of the DNA content and studied the motility response (MR) to laminin and fibronectin. FA results. The RC43 parental line showed a tetraploid pattern (DNA index: 2.08). Also the variant lines RC43MLI and RC43MDI were tetraploid (DNAind: 2.05 and 2.07, respectively). With RC43MDI a second peak in the tetraploid range was evident. The RC43MSP and the RC43MBO sublines both showed a hypertetraploid pattern (DNAind respectively 2.21 and 2.11). MR results. Motility studies showed that all RC43 lines, including the parental line, were stimulated to migrate in response to either laminin or fibronectin both from rat and human sources. There were no significant differences between the parental line and its variants in this respect, however. We conclude that by the use of FA at least two of the sublines (MSP and MBO) can be distinguished from the parental RC43 cell line, suggesting a different clonal origin of the various sublines. As all sublines, as well as the parental line, showed a large but similar response to migration-stimulating agents (such as laminin and fibronectin) determination of MR could not be used to obtain a further discrimination between the different sublines.

Prediction of recurrence and progression in primary superficial bladder cancer with DNA flow cytometry.

Intravesical chemotherapy has been well established as an effective therapy for recurrent superficial bladder tumors. We investigated the role of flow cytometry as a predictor of tumor recurrence/progression after intravesical chemotherapy. Flow cytometric analysis of nuclear DNA ploidy pattern was performed on 'cold cup' biopsy samples of 52 patients with primary superficial bladder cancer. Cell suspensions, retrieved after mechanical fragmentation, were stained with propidium iodide and examined on FACScan flow cytometer. Clinical follow-up ranged from 3 to 57 months with a median of 20 months. Of the 52 patients, 24 aneuploid and 28 diploid tumors were observed. The degree of ploidy in relation to histological grade showed an increasing frequency of aneuploid pattern in grades 2 and 3 but with no statistical significance. 17.8% of diploid tumors versus 54.1% of aneuploid tumors recurred (p less than 0.05). 12.5% of the aneuploid tumors progressed. No progression among diploid tumors was observed. Of the 52 patients examined, 35 (16 aneuploid and 19 diploid) were treated, after TUR, with intravesical prophylactic therapy. Epirubicin in 24, mitomycin C in 4 and recombinant interferon alpha 2a in 7 were used. 50% of aneuploid tumors versus 10.5% of diploid tumors recurred (p less than 0.05). Strong predictors of response to intravesical prophylaxis of recurrence were G1 grade and diploid DNA content.