Modeling Active Non-Markovian Oscillations.

Modeling noisy oscillations of active systems is one of the current challenges in physics and biology. Because the physical mechanisms of such processes are often difficult to identify, we propose a linear stochastic model driven by a non-Markovian bistable noise that is capable of generating self-sustained periodic oscillation. We derive analytical predictions for most relevant dynamical and thermodynamic properties of the model. This minimal model turns out to describe accurately bistablelike oscillatory motion of hair bundles in bullfrog sacculus, extracted from experimental data. Based on and in agreement with these data, we estimate the power required to sustain such active oscillations to be of the order of 100 k_{B}T per oscillation cycle.

Prevention of surgical site infections in orthopaedic surgery: a synthesis of current recommendations.

Despite adopted precautions, surgical site infection (SSI) rate in orthopaedic surgery and its consequences still remain a major problem. Worldwide, infection prevention and control in perioperative settings are considered of primary importance for every healthcare system. The management of perioperative infections carries a heavy psychological and financial burden, since patients who experience SSI have increased hospital length of stay, morbidity and mortality rates, and higher hospital costs. As the treatment of such infections is particularly difficult in the presence of an implanted biomaterial, the prevention of SSI in orthopaedic surgery represents a challenging key issue, requiring the integration of a range of measures before, during and after surgery. In fact, over the years several aspects of SSI prevention have been studied in order to identify the best SSI prevention strategies and set out appropriate clinical practices. This article will review and summarize the recent international guidelines released on this subject together with other published relevant evidence.

Chronic urticaria associated with thyroid carcinoma: report of 4 cases.

Chronic urticaria is a common condition that can be very disabling when severe. A variety of causes has been reported to induce urticaria, including food, infections, drugs and other factors. In more than 50% of cases of chronic urticaria, however, the cause remains unknown and cannot be ascribed to allergic, physical, environmental or other factors. Although an association between chronic idiopathic urticaria and malignancy has been occasionally reported, such an association remains controversial because it is difficult to demonstrate it is not just coincidental. Here we report the cases of four female patients with occult papillary carcinoma of the thyroid who developed chronic urticaria. In all of these cases, removal of the tumor led to prompt resolution of the urticarial lesions, thus suggesting a pathogenetic relationship between the two. This is the first report of papillary thyroid carcinomas associated with chronic urticaria and highlights how chronic urticaria may be an important cutaneous marker for patients with thyroid carcinoma.

Merkel cell carcinoma and HIV infection: a case report and review of the literature.

Merkel cell carcinoma (MCC) is a skin cancer of neuroendocrine origin that occurs most often in sun-exposed areas. In the general population, it is a disease of older adults, with only 5% of cases occurring below the age of 50 years. Immunosuppression is the significant risk factor for the development of MCC and recently it was suggested that individuals with HIV have a relative risk of 13.4 to developed MCC in comparison with the general population. We report a case of MCC in an HIV-infected patient and we review nine patients with HIV with MCC. Our patient was a 54-year-old man who came to our attention without a known HIV diagnosis. He was apparently in good health and had no risk factor for HIV, but by the atypical site of the lesion and by the relative young age of the patient we suspected a case of immunosuppression and for this reason we did HIV test that had a positive result. The patient was treated with surgery and chemotherapy but died as a result of liver metastases 25 months after his tumor was diagnosed.

[Surgical education: from teledidactics to virtual training]. / Dalla teledidattica alla realtà virtuale: come cambia la formazione del chirurgo.

The assessment of efficacy and quality of computer-assisted learning is today under evaluation. The Authors propose to use distant learning in the surgical knowledge teaching. In Italy, thanks to the Ministry of University and Scientific Research, a Master on distant learning in Medicine is now starting in 11 Italian Universities under the coordination of the second Faculty of Medicine of the University of Rome 'La Sapienza'. Thanks to the help of medicine and surgery teachers and informatics and telecommunication engineers, this Master is a first step to form and to license medical and surgical specialists experts in distant learning and videoconferencing telemedicine. Videoconferencing system can support Telementoring. Telementoring isn't an exclusive methodology but it is an additional methodology to tradictional didactic for clinicians and surgeons. It allows personal virtual trainings using computers and telecommunication systems.

[Rhomboid flap in radical surgical treatment of sacrococcygeal fistulas: technical notes]. / Il lembo di rotazione romboide nel trattameno chirurgico radicale delle fistole sacrocogginee: note di tecnica.

The Authors report their experience in surgical management of sacrococcygeal fistulas treated by radical excision and subcutaneous/cutaneous rhomboid flap. This is a simple, safe surgical technique and the patients can be treated in day surgery by spinal anesthesia.

Long-term clinical follow-up after successful repeat percutaneous intervention for stent restenosis.

OBJECTIVES: This study evaluated the long-term clinical outcome of successful repeat percutaneous intervention after in-stent restenosis. BACKGROUND: Recurrence of symptoms and angiographic restenosis after stent implantation are observed in 15% to 35% of cases. Repeat percutaneous treatment for in-stent restenosis has been shown to be safe, with high immediate success, but little is known about the long-term clinical outcome. METHODS: Clinical follow-up (minimum 9 months) was obtained in a consecutive series of 124 patients (127 vessels) presenting with stent restenosis who were successfully treated with repeat percutaneous intervention. RESULTS: Clinical follow-up was obtained in all 124 patients at a mean [+/-SD] of 27.4 +/- 14.7 months (range 9 to 66); a stress test was available in 88 patients (71%). Recurrence of clinical events occurred in 25 patients (20%) and included death from any cause in 2 patients (2%), target vessel revascularization in 14 (11%), myocardial infarction in 1 (1%) and positive stress test results or recurrence of symptoms (Canadian Cardiovascular Society class I to IV) treated medically in 8 (6%). Cumulative event-free survival at 12 and 24 months was 86.2% and 80.7%, respectively. Significant predictive factors of recurrence of clinical events were repeat intervention in saphenous vein grafts, multivessel disease, low ejection fraction and a < or = 3-month interval between stent implantation and repeat intervention. CONCLUSIONS: In-stent balloon angioplasty for stent restenosis in native vessels seems to be an effective method in terms of a low long-term clinical event rate.

Zinc and thymic hormone-dependent immunity in normal ageing and in patients with senile dementia of the Alzheimer type.

Plasma zinc levels were measured in young controls, aged controls, patients with dementia of the Alzheimer type and patients with non-Alzheimer type dementia. Zinc levels decreased with age; however, no difference was found between patients with dementia and age-matched controls. Plasma levels of active or inactive thymulin, a nonapeptide produced and released by the thymus gland, were also determined in young controls, aged controls, patients with dementia of the Alzheimer type and patients with non-Alzheimer type dementia. Basal levels of active thymulin were decreased in aged controls and in patients with dementia. In vitro reactivation of thymulin after zinc addition to plasma samples was decreased in aged controls. A further impairment of thymulin reactivation was present in patients with dementia. A significant age-dependent decrease in lymphocyte proliferation after mitogen stimulation was found; however, no difference was present between aged controls and patients with dementia of the Alzheimer type. Interleukin-2-induced cell activation and its effect on mitogen-induced proliferation were also measured; once again only an age-associated decrease was found. The endocrine function of the thymus of patients with dementia appears to be more compromised than that from aged controls.

Polytetrafluoroethylene-covered stent for the treatment of narrowings in aorticocoronary saphenous vein grafts.

We compared the outcome of patients with saphenous graft disease treated with polytetrafluoroethylene (PTFE)-covered stents or noncovered stents. Angiographic success was similar; non-Q-wave myocardial infarction was lower in the PTFE group (p = 0.06) and long-term major cardiac events and restenosis rate were similar in the 2 groups. Implantation of PTFE-covered stent in vein graft disease seems to reduce the occurrence of distal embolization.

Systemic acute-phase response after laparoscopic and open cholecystectomy.

BACKGROUND: Cytokines are the main mediators of inflammation and the response to trauma. The purpose of this study was to compare variations in cytokine levels following laparoscopic cholecystectomy (LC) and mini-laparotomy cholecystectomy (OC), since these two types of operations were considered to be a unique model for examining the role of local tissue injury in postoperative inflammatory reactions. METHODS: A total of 40 patients were studied. Eighteen of them underwent LC; the remaining 22 were operated on using the open technique. Systemic concentrations of interleukin-6 (IL-6), interleukin-1 (IL-1), tumor necrosis factor (TNF), and C-reactive protein (CRP) were measured before and after the operation. In addition, we compared pre- and postoperative white blood cell (WBC) counts, postoperative body temperature, and length of postoperative hospitalization. RESULTS: There was no difference between the two groups in IL-1 and TNF response. The rise in plasma IL-6 levels (18.86 +/- 9.61 vs 5.00 +/- 0.0 pg/ml, p < 0.0001) and CRP (8.40 +/- 5.81 vs 1.43 +/- 1.30 mg/dl, p < 0.001) were more marked after open cholecystectomy than after the laparoscopic procedure. There was no correlation between serum CRP concentrations and the other postoperative parameters. CONCLUSION: The magnitude of the acute-phase response was less pronounced following laparoscopic cholecystectomy, consistent with a reduction in tissue trauma.

Clinical and angiographic outcome after Palmaz-Schatz stent implantation guided by intravascular ultrasound.

Intracoronary stents can be implanted with a low incidence of stent thrombosis (< 1%) when the stent procedure is guided by intravascular ultrasound. The long-term clinical and angiographic effects, however, have not been reported. This study assesses the 6 month clinical and angiographic results of a consecutive series of patients with intravascular ultrasound guided Palmaz-Schatz stent deployment that were not treated with subsequent anticoagulation after a successful stent implantation procedure. From March, 1993 to April 1994, 411 patients underwent Palmaz-Schatz stent implantation. There were 26 patients that had uncomplicated Palmaz-Schatz stent implantation that were treated with a standard anticoagulation regimen that are not evaluated in this study. Thus, this study includes an assessment of 385 patients that had either a successful intravascular ultrasound guided stent implantation procedure and did not receive post procedure anticoagulation or had a procedural complication. Procedural success was achieved in 369 patients (96%). Clinical success (procedure success without early post procedure event) was achieved in 363 patients (94%). There were 2 acute stent thrombosis events (0.5%) and 1 subacute stent thrombosis (0.3%) in the group of 369 patients with 454 lesions treated without anticoagulation. At 6 month clinical follow-up the incidence of myocardial infarction was 4.9% and the rate of coronary bypass surgery was 6.2%. There was a 2.1% incidence of death. Emergency intervention (emergency angioplasty or bailout stent implantation was necessary in 3 patients (0.8%). The total incidence of repeat percutaneous intervention was 11.4%. By 6 months clinical follow-up, major events had occurred in 19.2% of patients. The angiographic lesion restenosis rate, according to 50% diameter stenosis criteria, was 19%. The incidence of restenosis per patient was 22%. In conclusion, intravascular ultrasound guided Palmaz-Schatz can be performed without subsequent anticoagulation with a low incidence of stent thrombosis and acceptable clinical and angiographic outcome at 6 month clinical follow-up.

Major acute inflammatory complications of diverticular disease of the colon: planning of surgical management.

BACKGROUND/AIMS: The aim of this study was to determine the most appropriate surgical strategy in the management of patients with major inflammatory complications of colonic diverticular disease. MATERIALS AND METHODS: Out of 259 patients affected by complicated diverticular disease of the colon, 43 consecutive patients (16.6%) who underwent urgent or emergency surgical intervention for diverticular perforation during a 20-year period (1975-1994) were retrospectively analyzed. According to the changes in the surgical approach over the time, the series was divided into two groups: 1975-1985 group A (n = 23), 1986-1994 group B (n = 20). The clinical diagnosis was confirmed by operative and pathologic findings. RESULTS: Out of 43 patients, 11 underwent derivative procedure and 32 resection. There were no significant differences among the two groups of patients according to sex ratio and mean age. The overall percentage of patients in group B who underwent resective procedure (100%) was significantly greater in comparison with that in group A (52%) (p < 0.001). Colostomy and drainage was employed only during the first period (30%)(vs group B, p < 0.05) and the proportion of patients who underwent primary resection and anastomosis was significantly higher during the second period (45%) (vs group A, p < 0.05). CONCLUSIONS: It must be stressed that resection of the diseased segment at initial operation appears mandatory; one-stage procedure is indicated when infection is confined to the mesentery, while resection and anastomosis with covering colostomy (two-stage procedure) is preferable whenever peritoneal contamination has occurred. Hartmann's operation remains the procedure of choice in the patients presenting known impaired immunity or fecal contamination.

Taurine distribution in rat tissues during development.

1. Taurine levels have been determined in eight rat organs. 2. During postnatal growth the taurine content in retina, heart, small intestine, spleen and lung increases with advancing age, although adult values are not reached at the same time. 3. In contrast the taurine content decreases with age in brain cortex, liver and kidney. 4. The taurine in subcellular fractions of adult, 20-day-old and 5-day-old rat tissues exists predominantly in the cytosol of the cell. Taurine content in particulate fractions shows marked variations during development in the different organs. 5. Taurine distribution in the subcellular fractions suggests that some of the cellular taurine in the tissues is not freely mobile in cytosol.

[Merkel cell tumor. A clinical case]. / Il tumore a cellule di Merkel. Caso clinico.

Merkel's tumor cells represent a rare neuroendocrine neoplasia type which belong to an apudomi group but it's different due to the absence of the biogen amine and hormone polypeptide production. The authors report a rare case of Merkel's tumor cells clinically evident with a great neoformation under the left axilla but already represents at the moment of discovery a notable diffusion with repetition as in hepatic and suprarenal gland. Pointing out not only clinic case having arrived at their observance but also it's important to take note of this particular neoplasia and to suspect it in case of doubt interpretation of clinical tumor.

Extra-articular localized nodular synovitis (giant cell tumor of tendon sheath origin) attached to the subtalar joint.

A large soft tissue mass of the left ankle was documented by ultrasonography in a 24-year-old man. Histologic examination of biopsy samples was consistent with pigmented villonodular synovitis. Magnetic resonance, performed to establish the extension of the mass, revealed an extra-articular lesion involving the posteromedial extra-articular soft tissues, which, by means of a thin peduncle, extended into the subtalar joint space. The mass was excised; gross and microscopic examinations were characteristic of localized nodular synovitis. Bone and cartilage abnormalities were not revealed by either preoperative imaging or surgery. At 15-month follow-up, the patient was free of recurrences. This case is an uncommon example of localized nodular synovitis of the subtalar joint, characterized by the absence of bone and articular cartilage abnormalities. In addition, this case reveals that the pattern of growth (i.e., the shape of the lesion) is an important factor in determining secondary lesions of bone and cartilage.

[Our experience with the orthotopic continent colonic neobladder]. / La nostra esperienza sulla neovescica colica ortotopica continente.

In the last years particular surgery operations became refined for the techniques and therapeutics progresses also developed in this field. This has allowed with major security to accomplish engagemently reconstruction operations after removal of the bladder, especially for cases of neoplastic pathology, to offer the patients a more normal quality of life avoiding urinary derivations that should change the performance of "EGO". After the operations of radical cystoprostatovesciculectomy different methods have been presented for the construction of heterotopical and orthotopical neobladder; among these the continent colic orthotopical neovesica of Goldwassern which uses the detubulization right colon, in our opinion could offer best functional and clinic results in virtue of easier execution and to use of minor number of intestinal segments. Moreover, for the peculiar characteristics of colic segment, allow to make a wide tank at low pression with perfect diurnal and nocturnal continence. We have, therefore, presenting the results of our experience regarding 12 cases of continent colic orthotopical neovesica, by Goldwasser, with a follow-up of 1-6 years which have comforted us with the results predicted. Although other techniques may offer similar results we believe that the Goldwasser method is still valid for all the above reasons.

[Assessment of the effects of alfuzosin on miction with dynamic echography]. / Valutazione degli effetti dell'alfuzosina sulla minzione mediante ecografia dinamica.

Alfuzosina has a specific antagonist effect on the alfa-1-adrenergic post-junctional receptor posed at urethral laeve musculature, prostatic capsule and vesical trgonum. It's and ideal drug the symptoms of the difficult urinary flow typical of the benign prostatic hypertrophia (IPB) and of some patologies of vesical collum to attenuate. With this work we want to demonstrate the anatomic alterations of vesical collum and prostatic urethra by means of dynamic recording mictional phase with transrectal scan carried out before and after treatment. In this study, 30 patients were divided into three groups of 10 in relation to the pathology: overtone of vesical collum, little benign prostatic ipertrophia and great benign prostatic ipertrophia have included. The patients of each group have also been divided in undergroups of five (selected with the method of double-blind) of which the first treated with alfuzosina 7.5 mg/die for 30 days and the second with placebo. Considering the limits of this study, the analysis of the results have permitted to conclude that the drug has determined a subjective improvement in all patients except those with great IPB, while the objective valuation, reached comparing scan dynamic pictures before and after treatment, has made it possible to visualize an improvement on the opening of the vesical collum and the prostatic urethra after therapy with great variations of the size of che mictional funnel and same prostatic urethra. The alfuzosina is efficacious, in the cases under examination, except the third group were the compression on the urethra was of an elevated degree.

[Tissue expression of carbohydrate antigen 19-9 (CA 19-9) in adenomatous lesions of the colorectum]. / Espressione tissutale dell'antigene carboidrato 19-9 (CA 19-9) nelle lesioni adenomatose del colon-retto.

Serum levels of tumor markers almost not detectable in precancerous states or early cancer, the behavior of the tumor associated antigen CA 19-9 in colorectal carcinogenesis was analysed. In order to investigate the adenoma-carcinoma sequence, tissue antigenic expression was measured in adenomas, characterized by different size and histology, and compared with that found in normal colonic mucosa. Tissue content of CA 19-9 was determined by an immunoperoxidase technique (ABC-POD) in 88 colonic polyps, and correlated to the degree of histological dysplasia, and dimension of adenoma. Tissue content of CA 19-9 was also evaluated in non-adenomatous mucosa obtained by endoscopic biopsy. Among the 88 polyps, 50 showed the tubular histological type, while 31 resulted tubulovillous and 7 villous. High degree of dysplasia was present in 7 adenomas (7.9%) and focal carcinoma was observed in 6 (6.8%). Positivity for CA 19-9 was registered in 60.2% of adenomas. No correlation was found between tissue-CA 19-9 and degree of dysplasia, size of adenoma and villous component. However, a statistically significant correlation was observed between expression and cellular distribution of the antigen (chi 2 = 98.07, p < 0.00001). Our data confirmed CA 19-9 expression in adenomas, but it is unlikely this tissue antigen proves to be a reliable marker of adenoma-carcinoma sequence.