On modelling the interaction between two rotating bodies with statistically distributed features: an application to dressing of grinding wheels.

The mechanisms of interaction between bodies with statistically arranged features present characteristics common to different abrasive processes, such as dressing of abrasive tools. In contrast with the current empirical approach used to estimate the results of operations based on attritive interactions, the method we present in this paper allows us to predict the output forces and the topography of a simulated grinding wheel for a set of specific operational parameters (speed ratio and radial feed-rate), providing a thorough understanding of the complex mechanisms regulating these processes. In modelling the dressing mechanisms, the abrasive characteristics of both bodies (grain size, geometry, inter-space and protrusion) are first simulated; thus, their interaction is simulated in terms of grain collisions. Exploiting a specifically designed contact/impact evaluation algorithm, the model simulates the collisional effects of the dresser abrasives on the grinding wheel topography (grain fracture/break-out). The method has been tested for the case of a diamond rotary dresser, predicting output forces within less than 10% error and obtaining experimentally validated grinding wheel topographies. The study provides a fundamental understanding of the dressing operation, enabling the improvement of its performance in an industrial scenario, while being of general interest in modelling collision-based processes involving statistically distributed elements.

[Mesothelial cyst of the kidney. A rare case report of this neoformation on the left kidney].

The authors are hereby presenting a rare case of neoformation developing on the left kidney in a 80-year-old patient affected by left lumbar backache. The neoformation appears doubtful in nature, on ultrasonography, CT scan and MRI. The lesion is roundish and contiguous at the kidney convex edge; due to its clinical aspects, it requires a surgical management and is, therefore, easily excised. The histopathologic examination confirms it is a mesothelial cyst. The case is presented for its absolute rarity and for the preoperative diagnostic doubts it may generate.

[Angiomyofibroblastoma of the spermatic funiculus. A case report of this lesion of the spermatic funiculus].

The authors are hereby presenting a rare case of angiomyofibroblastoma of the funiculus in a 20-year-old patient, having a non-aching tumefaction at the left region of the scrotum. This tumefaction was solid and non homogeneous, both on ultrasonography and MRI, of about 5cm in diameter, fully separated from the testicle. The markers were all negative. We proceeded with surgical treatment of the neoformation. It is mandatory to include this lesion within the differential diagnosis of testicle masses. The case is presented for its absolute histopathologic rarity and for the difficulty in diagnosis.

Role of Ca 15-3 in patients with biochemically suspected prostate cancer and multiple negative ultrasound-guided prostate biopsies.

Ca 15-3 is an aspecific tumor marker characteristic of cancer proliferation. Elevated serum levels seem to be closely correlated with cancer progression in non-urological tumors. This study assessed the role of Ca 15-3 as an aspecific tumor marker in patients with borderline prostate-specific antigen (PSA) biochemically suspected of prostate cancer (PCa) and with multiple negative prostate biopsies. The study is based on prospective analysis of 103 patients: (a) 33 patients (group A) presented lower urinary tract symptoms secondary to BPH with normal serum PSA values, DRE and TRUS negative for suspected PCa; (b) 31 patients (group B) with histologically diagnosed PCa; (c) 39 patients (group C) with borderline serum PSA values, DRE and TRUS normal, two ultrasound (US)-guided random prostate biopsies negative for PCa. Ca 15-3 was determined in the entire study series by the IRMA method, using as range the values proposed for the investigated non-urological tumors (38 UI/l).Ca 15-3 was within normal range in all group A patients (control), while the values were elevated in 27/31 of group B patients (PCa) and in 11/39 of group C (PCa suspected) patients. A third biopsy was performed in all 39 group C patients with borderline PSA and it was PCa-positive in 13 patients (33.3%, subgroup C3). In this series Ca 15-3 was increased in 9 of 13 patients (subgroup C3alpha), while the remaining four patients (subgroup C3beta) presented values within the normal range. On 26 group C patients who were negative for PCa to third biopsy (subgroup C4), 24 patients had Ca 15-3 levels within normal range (subgroup C4alpha) with histologic findings of BPH in 23 cases and granulomatous chronic prostatitis in one case, while two patients (subgroup C4beta) had elevated Ca 15-3 concentrations associated with lymphoplasmacytic chronic prostatitis. We hypothesize that Ca 15-3, as a specific tumor marker, could be an interesting and inexpensive second step diagnostic tool for PCa in patients with borderline PSA and multiple negative prostate biopsies, as it could indicate whether a repeated biopsy should be performed in a short time, having excluded other concomitant tumors. However, further prospective studies will be necessary to confirm this hypothesis.

Randomized crossover comparison of right atrial appendage pacing versus interatrial septum pacing for prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia.

BACKGROUND: New atrial pacing techniques and overdrive pacing algorithms have been introduced to prevent atrial fibrillation. This study was designed to test the hypotheses that (1) interatrial septum pacing (IASP) at the triangle of Koch would be more effective than right atrial appendage pacing (RAAP) in preventing paroxysmal atrial fibrillation (PAF) in patients with sinus bradycardia and (2) an algorithm (CAP) designed to achieve constant atrial capture would increase the efficacy of rate-responsive atrial pacing. METHODS: We studied 46 patients with PAF and sinus bradycardia implanted with a DDD(R) (Medtronic Thera) pacemaker. Twenty-four patients (6.0 +/- 10.1 PAF episodes/month within 3 months before study) were randomized to RAAP and 22 patients (5.4 +/- 7.1, not significant) to IASP. Within each arm 2 randomized crossover periods of CAP-OFF and CAP-ON function were programed. RESULTS: The PAF episodes per month significantly decreased in the RAAP (CAP-OFF: 2.1 +/- 4.2, P <.05; CAP-ON: 1.9 +/- 3.8, P <.05) and in the IASP group (CAP-OFF: 0.2 +/- 0.5, P <.05; CAP-ON: 0.2 +/- 0.5, P <.05). Values were significantly lower in the IASP group than in the RAAP group in both CAP-OFF (0.2 +/- 0.5 vs 2.1 +/- 4.2, P <.05) and CAP-ON (0.2 +/- 0.5 vs 1.9 +/- 3.8, P <.05) conditions. PAF burden was significantly lower in the IASP than in the RAAP group in CAP-OFF (47 +/- 84 min/d vs 140 +/- 217, P <.05) and in CAP-ON (41 +/- 72 vs 193 +/- 266, P <.05) conditions. No differences were observed within each arm in PAF burden between the 2 crossover CAP programing periods. CONCLUSIONS: Rate-adaptive IASP at the triangle of Koch is more effective than RAAP in preventing PAF in patients with sinus bradycardia. In our sample of patients no additional clinical benefit is furnished by the CAP algorithm.

Impact of consistent atrial pacing algorithm on premature atrial complexe number and paroxysmal atrial fibrillation recurrences in brady-tachy syndrome: a randomized prospective cross over study.

AIM OF THE STUDY: The Consistent Atrial Pacing (CAP) algorithm has been designed to achieve a high percentage of atrial pacing to suppress paroxysmal atrial fibrillation. The aim of our study was to compare the impact of DDDR+CAP versus DDDR pacing on paroxysmal atrial fibrillation recurrences and triggers in patients with Brady-Tachy Syndrome. METHODS: 61 patients, 23 M and 38 F, mean age 75+/-9 y, affected by Brady-Tachy Syndrome, implanted with a DDDR pacemaker, were randomized to DDDR or DDDR+CAP pacing with cross over of pacing modality after 1 month. RESULTS: 78 % of patients in DDDR pacing and 73 % in DDDR + CAP pacing (p=n.s.) were free from symptomatic paroxysmal atrial fibrillation recurrences. During DDDR+CAP pacing, the atrial pacing percentage increased from 77+/-29 % to 96+/-7 % (p<0.0001). Automatic mode switch episodes/day were 0.73+/-1.09 in DDDR and 0.79+/-1.14 (p=n.s.) in DDDR+CAP. In patients with less than 50 % of atrial pacing during DDDR, automaticmode switch episodes/day decreased during DDDR+CAP from 1.13+/-1.59 to 0.23+/-0.32 (p<0.05) and in patients with less than 90 % from 1.23+/-1.27 to 0.75+/-1.10 (p<0.001). The number of premature atrial complexes per day decreased during DDDR + CAP from 2665+/-4468 to 556+/-704 (p<0.02). CONCLUSION: CAP algorithm allowed continuous overdrive atrial pacing without major side effects. Triggers of paroxysmal atrial fibrillation induction, such as premature atrial complexes, were critically decreased. Paroxysmal atrial fibrillation episodes were reduced in patients with atrial pacing percentage lower than 90 % during DDDR pacing.

Immunohistochemical and molecular analysis in recurrent urethral stricture.

The authors have analyzed the most recent additions to the literature of immunohistochemical and molecular assessment of acquired urethral strictures and report on their data obtained in a selected clinical series. Innovative immunohistochemical studies in patients presenting with plurirecurrent symptoms suggest that urethral mesenchymal changes caused by tissue de-epithelialization may be the underlying cause of stricture. This condition may be congenital or acquired. It may determine aberrant connective tissue formation induced by abnormal fibroblastic activation with formation of over abundant hyperdense collagen scar tissue.

Antiarrhythmic benefits of dual chamber stimulation with rate-response in patients with paroxysmal atrial fibrillation and chronotropic incompetence: a prospective, multicentre study.

BACKGROUND: While the haemodynamic benefits of DDDR pacing compared with DDD pacing in patients with brady-tachy syndrome and chronotropic incompetence (CI) are well demonstrated, the antiarrhythmic advantage is controversial and so far not clearly demonstrated. AIM: We have performed a prospective, randomized, multicentre study to evaluate the efficacy of DDDR and DDD pacing modes in preventing paroxysmal atrial fibrillation (PAF) episodes in patients with brady-tachy syndrome and CI. METHODS AND RESULTS: Seventy-eight patients were included in the study. All patients had a dual chamber pacemaker implanted and were randomly programmed to DDD or DDDR with a cross over (DDD --> DDDR or vice versa) at 3 months. The final evaluation was performed at 6 months by means of two self-administered symptom questionnaires to evaluate activity. Symptoms of palpitations were analysed and scored. The patients were less symptomatic with the DDDR mode. The number of mode-switch activations compared with symptomatic episodes of PAF confirmed the high rate of asymptomatic PAF episodes in patients with brady-tachy syndrome. We conclude that in a small but well defined population of patients affected by sick sinus syndrome with CI and severely symptomatic PAF, DDDR pacing compared with DDD pacing may offer an additional antiarrhythmic benefit and should be considered the primary mode of pacing.

[Paroxetine in the treatment of premature ejaculation]. / La paroxetina nel trattamento dell'eiaculazione precoce.

This study evaluated paroxetine as a possible treatment for premature ejaculation. Sixty two patients affected by primary premature ejaculation were randomly assigned to two groups. A and B, and treated with two different treatment schedules. Patients assigned to group A were treated with paroxetine 20 mg p.o. daily for six months; patients assigned to group B were treated with paroxetine 20 mg p.o. daily for fourteen days, and than dose was reduced to 10 mg for a total treatment period of six months. Only one patient reported significative side effects (weakness). Positive clinical results were obtained, at the end of the treatment, in 89 per cent of group A and 88 per cent of group B. In patients with primary premature ejaculation, paroxetine represents, in our opinion, the best therapeutic option for its efficacy and lack of significant side effects.

Reliability of a new algorithm for automatic mode switching from DDDR to DDIR pacing mode in sinus node disease patients with chronotropic incompetence and recurrent paroxysmal atrial fibrillation.

To evaluate the safety and efficacy of a new algorithm for automatic mode switching (AMS) from DDD-DDDR to DDIR, 26 patients, 16 females and 10 males, mean age 73 +/- 6 years of age, affected by sinus node disease, chronotropic incompetence, and recurrent paroxysmal atrial fibrillation (PAF) received the Medtronic Thera DR pacemaker. The device continuously calculates, in ms, the running average of the intrinsic atrial rate (MAR) and compares the current atrial interval (CAI) with the stored MAR. When the CAI is greater than the MAR it increases by 8 ms, and when the CAI is less than the MAR, it decreases by 23 ms. When MAR < or = 330 ms (182 beats/min), tachycardia is detected and AMS is activated. All patients had clinical evaluation, 12-lead ECG, Holter monitoring, and exercise testing after implantation and every 3 months for 1 year. The results were compared with the data stored in the pacemaker memory: AMS episodes number; the histogram of the last 14 episodes; and atrial electrogram recording. Twenty-two Holter recordings in 13 patients showed PAF and in all of them AMS occurred simultaneously. AMS lasted between 10 seconds and 20 hours, and MAR ranged from 195-400 beats/min. No episode of PAF and no AMS were recorded in 39 Holter recordings in 22 patients. Appropriate AMS was confirmed in five patients by stored atrial electrogram and in nine by 12-lead ECG and pacemaker event markers. Mean atrial sensing was 2.13 +/- 1.04 mV during PAF and 3.18 +/- 1.46 mV during sinus rhythm. No PAF episode and no AMS were recorded during exercise testing. In conclusion, this new algorithm was very reliable, sensitive, and specific.

[Use of stents in postoperative recurrent urethral stenosis]. / L'uso degli stent nelle stenosi uretrali post-operatorie plurirecidive.

We have started study after a publication (1) about our experience on 1376 urethrotomies executed above 784 patients; the 11% of these stenosis have been consequent on endoscopic or open surgery. In the 23% of these patients we have made more than two urethrotomies and in 4% of these the endoscopic operation has not been resolutive. We described the use of the urethral wall stent in 13 patients with recurring urethral strictures. The stainless steel stent is self expanding when released from its endoscopic introducer. We have desobstructed the 100% of the patients and obtained a max flow between 15 and 24 ml/sec. We haven't had problems of re-epithelialization if excluded two patients where observed a stabilized exuberant re-epithelialization without uroflowmetry variations. It is considered that this endoscopic technique offers a simple, safe and effective alternative to multiple dilatations and urethrotomies in patients with bulbar urethral strictures.

Professional DOC (PDOC): a software environment for authoring and consulting of electronic documentation. INTERACTIVE DIAGNOSIS and THERAPY: a medical application.

Professional DOC (PDOC) is a software environment for electronic documentation authoring and consulting based on the Hypermedia technology. It allows to manage different kinds of information (pictures, sounds, texts, graphics, video) organized according to hyperstructures. The user-friendliness and effectiveness of its man-machine interface, and its availability on the most common hardware platforms makes it a suitable product for a very broad category of users. INTERACTIVE DIAGNOSIS AND THERAPY is an electronic medical book designed to help general practitioners to make diagnosis and treat patients in their daily clinic practice.