Quantitative versus qualitative modeling: a complementary approach in ecosystem study.

Natural disturbance or human perturbation act upon ecosystems by changing some dynamical parameters of one or more species. Foreseeing these modifications is necessary before embarking on an intervention: predictions may help to assess management options and define hypothesis for interventions. Models become valuable tools for studying and making predictions only when they capture types of interactions and their magnitude. Quantitative models are more precise and specific about a system, but require a large effort in model construction. Because of this very often ecological systems remain only partially specified and one possible approach to their description and analysis comes from qualitative modelling. Qualitative models yield predictions as directions of change in species abundance but in complex systems these predictions are often ambiguous, being the result of opposite actions exerted on the same species by way of multiple pathways of interactions. Again, to avoid such ambiguities one needs to know the intensity of all links in the system. One way to make link magnitude explicit in a way that can be used in qualitative analysis is described in this paper and takes advantage of another type of ecosystem representation: ecological flow networks. These flow diagrams contain the structure, the relative position and the connections between the components of a system, and the quantity of matter flowing along every connection. In this paper it is shown how these ecological flow networks can be used to produce a quantitative model similar to the qualitative counterpart. Analyzed through the apparatus of loop analysis this quantitative model yields predictions that are by no means ambiguous, solving in an elegant way the basic problem of qualitative analysis. The approach adopted in this work is still preliminary and we must be careful in its application.

[Anterior urethral therapy].

Surgical treatment of anterior urethral stenosis encompasses a large number of techniques. In literature there are few prospective studies that could compare the efficacy of different techniques. Most of these studies are retrospective and not multicentric. We present a review of the literature on the treatment of penile and bulbar strictures, focusing the attention on different kinds and numbers of complication, and showing shortand long-term results of each technique.

[Oncological and functional results of laparoscopic radical prostatectomy after 100 procedures: our experience].

Laparoscopic radical prostatectomy plays an emerging role in the surgical management of prostatic tumors. We present our experience of the first 100 cases of extraperitoneal laparoscopic radical prostatectomy. Our results about continence, erectile function and surgical margins are reported. MATERIALS AND METHODS. Between January 2005 and December 2007, 100 laparoscopic radical prostatectomies were performed by one surgeon. We retrospectively reviewed margins status, operative time, blood transfusion rates, time of catheterization, length of hospital stay, continence and potency rates. RESULTS. The operative time decreased during the learning curve. The mean duration of surgery was 240 minutes (in the first 25 procedures the median time was 320 minutes, while in the last 25 cases the mean duration was 200 minutes). Five conversions to open surgery were required owing to failure to progress. The overall rate of positive surgical margins was 15% in pT2 and 35% in pT3a tumors. We had 3 minor complications (two anastomotic leakage and one hemorrhage from the anastomosis) and 2 major complications (recto-urethral fistula). The mean intraoperative blood loss was 450 ml (range 200-1500). With regard to transfusion, 25 patients (25%) received their autologous units, while 2% of the patients required homologous units. The mean duration of catheterization was 7.8 days. The continence rate at 12 months was 85%; the potency rate was 55% at 12 months. CONCLUSIONS. The results of the present study show that by using a rational approach to training, a general urologist with low experience in laparoscopy is able to safely perform laparoscopic radical prostatectomy, and with oncological and functional results comparable to those of other published series.

[Features of diabetic angiopathy: impotence]. / Aspetti dell'angiopatia diabetica: l'impotenza.

Erectile dysfunction occurs more frequently in the diabetic population than in the general population. This article analyzes a review of this pathology, its prevalence and incidence in the diabetic population, its multifactor origin, and how these causes interact with each other and the therapy required.

[Interstitial cystitis: epidemiology]. / La cistite interstiziale: epidemiologia.

The epidemiological assessment of intestitial cystitis (IC) is not definitive as no diagnostic criteria, such as endoscopy or biochemical and anatomopathological examination, exist. The diagnosis is solely based on symptoms like urgency, frequency and pelvic pain. The first studies on the population date back from 20 years ago and show a percentage of 10 cases every 100 thousand inhabitants. There is weak link between genetic factors, immunological diseases, previous cystitis or eating habits and intestitial cystitis. Epidemiological studies have highlight the frequency of this disease, and stressed the importance of stricted behavioural rules for the first stages of intestitial cystitis.

[Interstitial cystitis: surgical treatment]. / Cistite interstiziale: terapia chirurgica.

Surgical therapy of interstitial cystitis must never be considered a first option but must be reserved for cases, less than 10%, in which conservative therapy has proven ineffectual. Surgical therapy includes a variety that started at the turn of the century. Neurosurgical denervation and perivesical denervation like cysto-cystoplasty and cystolysis, manipulate the innervation to reduce the bladder's hypersensitivity. This surgical approach may be considered in patients in whom bladder capacity is normal. The results are uncertain and the complications like neurogenic bladder relevant. Enterocystoplasty is much more widespread because interstitial cystitis is a benign disease that rarely required radical surgery. Augmentation cystoplasty and substitution cystoplasty are two variants but only the later has a rationale as it involves the resection of the detrusor which is the source of the pain. Detubularization drastically reduced urinary incontinence. The resection of the detrusor can be supratrigonal, subtrigonal or at the proximal urethra like in the orthotopic neobladder. If urinary diversion is chosen, the bladder must be removed. Before recommending surgical therapy each patient should undergo tests for the localization of the pain; moreover psychological and gynaecological evaluations should be made. If the bladder capacity exceeds 400 cc surgical operation is not advisable. If, on the other hand, the bladder capacity is lower than 400 cc substitution cystoplasty is first choice. If the patient suffers from trigonal cystitis or urethral hypersensitivity, urinary diversion is a better therapy. According to the questionnaires send to the Urologic Departments in Lombardy in 1998, the most widespread type of operation seems to be supratrigonal cystectomy + enterocystoplasty and augmentation cystoplasty. Subtrigonal cystectomy or urinary diversion are only occasionally chosen; continent pouch is the least frequent therapy at all.

[Replacement neobladders in men and women: our experience]. / Le neovesciche di sostituzione nell'uomo e nella donna: nostra esperienza.

We present our clinical and metabolic follow-up data of 74 patients submitted to total bladder substitution using an ileal orthotopic neobladder in one group of 64 patients and a continent stomal pouch in another group of 10 patients. In the first group the mean follow-up was 41.5 months. The daytime continence was early achieved in 89% (57/64) and was maintained with time; at 12 month follow-up nocturnal continence was reached in 71% (45/64). Post voiding residual was significant only in 4 patients (2 men and 2 women). No clinical signs of pyelonephritis nor renal scars at IVP was evidenced in all but 7 patients in which a silent uretero-ileal stenosis developed. No severe metabolic acidosis or B 12 deficiency occurred. In the second group (Continent Pouch) the long term 3-Year follow-up shows a complete continence in all patients with an average capacity of 600 cc. No late complications occurred in all patients but one in which self intermittent catheterization was uncomfortable and now he prefer permanent catheter and in another patient with a stone in the Pouch treated with Lithoclast. In conclusion, total bladder substitution after radical cystectomy is now represented by orthotopic neobladder or continent Pouch in men and women. Early and late complication rate is relatively low and continence generally good.

[Turbo TURP]. / Turbo TURP.

Transurethral resection of the prostate (TURP) is just one of the numerous options available in the modern treatment of benign prostatic hyperplasia (BPH), but it's still now the "gold standard". Absorption of irrigating fluid is the greatest complication and results in clinical manifestations in 2% of the TURPs performed. There is a statistically significant relationship between gland size and the total volume of irrigant absorbed. To reduce this absorption Reuter introduced suprapubic trocar drainage to obtain the same results from both the small and the large prostates. Operating time, in fact, is reduced because, also at the same time, this large tube drains both irrigation fluid and prostatic chips.

[Our experience with impotence following radical pelvic surgery]. / La nostra esperienza sulla impotenza dopo chirurgia radiacale pelvica.

The etiology of impotence after radical prostatectomy and radical cystoprostatectomy is unclear, although a variety of potential factors have been cited: neurogenic, psychogenic and vascular. Injury to the pelvic nerve plexus and the branches that innervate the corpora cavernosa (cavernous nerves), seems to be the most important iatrogenic factor. The Authors selected 14 patients candidate to radical prostatectomy or radical cystoprostatectomy and studied their potency pre and post operatively by anamnesis and/or Rigiscan test. The sacral-evoked potential was determined in all these patients in order to detect a neurological etiologies. The average latency of the bulbo cavernous reflex was similar in the patients that lost their potency after surgery and in the patients that didn't lose their potency after surgery. The sacral-evoked response seems not to be a diagnostic test in the study of the impotence after pelvic radical surgery.

[Transrectal echography in the diagnosis of cervico-urethral obstruction in the young]. / L'ecografia transrettale nella diagnostica dell'ostruzione cervico-uretrale giovanile.

The authors present a case of severe cervico-urethral obstruction by Von Brunn cysts. These cysts are often found even in macroscopically healthy bladders, but only rarely reach such a size as to be revealed by ultrasound. They can be asymptomatic or cause obstruction if large. They are no longer considered preneoplastic lesions and are therefore treated according to symptoms. When these cysts cause dysuria they are removed, preferably by transurethral resection, as it is the only method (unlike needle aspiration) which prevents recurrence.

[Echography in the diagnosis of postoperative complication in gynecology]. / L'ecografia nella diagnostica delle complicanze post-chirurgiche in ginecologia.

The authors report their experience regarding the use of ultrasonic instruments to control the postoperative iter of gynecological, oncological or urological surgery. These types of surgery may be complicated by urethral lesions, retroperitoneal or subfascial sero-hematic stasis, lymphocele, urethrohydronephrosis or vescical dysfunctions with urinary stasis which, if identified at an early stage, can be resolved by surgery. Out of 88 cases of gynecological surgery with a high risk of complications which were followed using ultrasound during the postoperative period, complications occurred in 11 cases (12.5%): their early identification also enabled adequate treatment to be performed using an echo-guided aspirated needle technique or using the application of drainage catheters.

[Lymphoma of the bladder. Description of 2 cases and review of the literature]. / Linfomi a localizzazione vescicale. Descrizione di due casi e revisione della letteratura.

Two case reports and review of the literature. The authors describe one case of primary lymphoma and one case of secondary lymphoma of the bladder. They evaluate the differences, underline the rarity of the primitive type and make a review of the literature.

[Suprapubic bladder ultrasonography and urinary cytology: indications and limits in the follow-up of superficial bladder tumors]. / Ultrasonografia vescicale sovrapubica e citologia urinaria: indicazioni e limiti nel follow-up dei tumori superficiali della vescica.

139 patients underwent urinary cytology and bladder sonography in follow-up of superficial bladder cancer (Ta G1-3) alternatively or at the same time of cystoscopy. Medium follow-up was 27.2 mos. In 7.91% there was progression to T1 o T2 but no case escaped this protocol. In 9% urinary cytology and bladder sonography were both falsely negative: tumors were smaller than 0.5 cm and low grade. In 76 patients with Tar bladder cystoscopy rate was 1/5.2 mos. before this study and 1/7.2 mos. after this study. In our opinion this protocol reveals the recurrence of superficial bladder tumor, reduce cystoscopy rate with no risk of ignored progression.

Ovarian remnant syndrome: a case report.

A case is reported of ureteral obstruction due to retained corpus luteum. The patient had previously undergone a hysterectomy and salpingo-ovariectomy with incomplete removal of ovarian tissue on both sides. The ureteral obstruction was treated by the excision of the mass and the reimplantation of the obstructed ureter into the bladder hitched to psoas muscle.

[Cryptorchism and fertility. Our experience]. / Criptorchidismo e fertilità. La nostra esperienza.

The relationship between cryptorchidism and fertility has been suggested in a lot of ways but hasn't been clearly demonstrated. In our Institute from 1981 until 1987, 352 orchidopexies had been performed. Out of these, 31 patients were studied with respect to the current age, the age at the surgery, the absence of varicocele and the possible iatrogenic damages. The rate of dispermia among the subjects studied, was 43% whereas 57% had normospermia. 3 out of 4 patients operated for bilateral undescended testis were azoospermic. The volume of unaffected testis is directly related to the health of the seminal status.