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.

Rectus sheath haematoma: are there prognostic risk factors of haemodynamic instability motivating an early operative treatment?

PURPOSE: Rectus sheath haematoma (RSH) is an uncommon condition caused by lesion of the superior or inferior epigastric arteries or their branches or by rupture of the rectus muscle. Treatment is usually supportive; however, if haemodynamic compromise develops, intravascular embolisation or surgery may be required. Furthermore, in some cases, bleeding may be so conspicuous that it can determine the patient's death before an adequate treatment is performed. We performed a retrospective study on 78 consecutive patients with the diagnosis of RSH admitted to the General Surgery Unit of our hospital between January 2000 and December 2010 in order to identify possible prognostic risk factors that could affect the operational approach before the onset of haemodynamic instability. METHODS: Demographic characteristics, patient history, laboratory and diagnostic imaging examinations were investigated. The variables considered were: gender, age, anti-coagulation or anti-platelet therapy, trauma, international normalised ratio (INR) and bleeding time in the first 72 h of observation and concomitant diseases. The data were used for statistical analysis. RESULTS: Sixty patients received a conservative treatment, while 18 underwent operative treatment for haemodynamic instability (embolisation in 2 patients and surgery in 16 patients). Three of these 18 patients (17 %) died for consumption coagulopathy after surgery. None of the variables included in the univariate statistical analysis was significant (p = ns). CONCLUSION: Ultrasonography or computed tomography are the most common methods used to establish the diagnosis of RSH, so it is no longer a diagnostic dilemma. Most patients can be treated conservatively and an operative treatment is justified only in case of haemodynamic instability. Our retrospective study could not identify any prognostic risk factor of haemodynamic instability in RSH. We believe that only a close observation of the patients with RSH and "common sense" can prevent a possible fatal outcome.

The importance of self-examination in the earliest diagnosis of multiple primary cutaneous melanomas: a report of 47 cases.

BACKGROUND: Development of more than one primary melanoma in a patient is a relatively uncommon but well-recognized phenomenon. Its frequency has ranged from 1.2% to 8.2% in several series. This subgroup of patients with multiple primary lesions has not been characterized sufficiently. We report the experience of the Melanoma Unit of University Hospital Spedali Civili of Brescia, Italy. METHOD: Study subjects were drawn from 1240 patients with histologically confirmed melanoma, including melanoma in situ. From this group, multiple melanomas developed in 47 patients (3.79%). Every one of our patients has been taught to perform self-examination of the skin to detect suspicious pigmented lesions. RESULTS: Of the 47 patients described in this study, 38 had two primary melanomas, 7 had three melanomas and 2 had 5 and 10 melanomas, respectively. Mean age at first diagnosis was 46.2 years. The majority of subsequent melanomas (74.5%) were removed within 5 years of the initial operation. Synchronous lesions were found in 10 patients. In male patients, the lesion appeared most frequently on the trunk; in female patients, melanoma appeared mostly on the lower extremities. The second primary melanomas developed in the same anatomic region from the first in 53.2% of our patients. The proportion of in situ to invasive melanomas was greater for the second melanomas compared with the first melanomas. Regarding invasive melanomas, the mean thickness of the first melanomas was 1.31 mm compared with 0.66 mm for the second ones. Dividing patients into two groups, of more and less than 50, it is highlighted that in older patients synchronous lesions appear more frequently (36.4% vs. 8.0%); the median time interval between sequential melanomas is longer (84 vs. 63.7 months); and the ratio between the primary and secondary melanoma mean thickness is lower (1.21 : 1.08 vs. 1.43 : 0.63 mm). CONCLUSIONS: The study confirms that second primary melanoma is usually thinner than the first lesion, and it is more common in the same region of the body as the initial melanoma. The highest risk for a second melanoma is during the first 5 years, but a much longer time interval of 28 years is possible. Continued medical follow-up with complete skin examinations seems prudent, but it is very important to promote self-skin evaluation in patients to detect not only metastases but also subsequent primary melanomas in their earliest phases.

[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.

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.

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.

[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.

[Changes in the expression of cellular alpha and beta tubulins in patients with sporadic type colorectal cancer]. / Alterazione della espressione delle tubuline cellulari alfa e beta in pazienti affetti da cancro colorettale di tipo sporadico.

The aim of this preliminar report is to evaluate alfa and beta tubulins, components of cellular microtubules, alterated expression in sporadic colorectal cancer patients. The Authors considered 16 patients who underwent surgery for sporadic colorectal carcinoma with radical intent. Alfa and beta tubulins were evaluated in tumoral mucosa by immunohistochemistry. In 56.2% of the examined patients a low expression of alfa and beta tubulins was showed while the alteration of alfa tubulin was showed in 81.2% of the patients. This finding supports the hypothesis of Porter that alterations in microtubule structure might be part of the cellular response to DNA damage.

[Telementoring in surgery]. / Il telementoring in chirurgia.

Tele-mentoring is an interactive experimental method that allows young surgeons' education by distant learning tutoring of an expert surgeon. The problem about assessment of efficacy and quality of computer-assisted instruction is under evaluation today. Tele-mentoring is supported by videoconferencing system and it is not an exclusive methodology but an additional methodology to traditional didactic for clinicians and surgeons. It allows personal virtual trainings by computers and telecommunication systems. Videoconference allows tutoring for telemedicine, teletriage and telesurgery also.

Study of the antireflux function of the Roux-en-y jejunal loop in reconstruction following gastrectomy.

Persistence of global orthograde peristaltic propulsion in the Y jejunal loop according to Roux makes this latter adequate for reconstruction of digestive transit after gastric resection or total gastrectomy, simultaneously avoiding reflux. Ectopic pacemakers can set in its proximal tract and favor intestinal and bile juice reflux in the gastric stump or esophagus, especially if the loop is too short and the new pacemaker is far from its superior margin. Moreover, the slower peristaltic waves can favor a relative stasis and, thus, a containing function, which could represent an element of morbidity over a certain limit. If the Y loop is not too long, but long enough to include the higher frequency ectopic pacemaker, which overcomes the lower frequency ones located distally, the positive aspects of both these characteristics can be exploited for satisfying and free of morbidity results. We believe that the best length is 35-40 cm, with positive clinical results. 99Tc-HIDA sequential scintigraphy clearly shows the absence of bile material reflux in the digestive tract proximal to the anastomosis.

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.

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.

[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.

Follicular carcinoma in ectopic thyroid gland. A case report.

Ectopic thyroid rest can be seen anywhere along the path of descent of the gland. The most ectopic thyroid tissue is a thyroglossal duct cyst associated with normal thyroid gland. Sublingual location is less common than a lingual ectopia. True malignant transformation in ectopic thyroid tissue is extremely rare. Such a malignancy is virtually always diagnosed only after surgical excision of the lesion at pathological examination. This report discusses a case of ectopic thyroid follicular carcinoma in the right submandibular region in the absence of orthotopic thyroid, discovered by chance after the surgical excision performed for a preoperative ultrasonically and cytologically misdiagnosed submandibular gland adenocystic carcinoma. The possible aetiology of such an unusual anatomical relationship is discussed as well as the importance of thyroid scanning, ultrasound and/or CT in neck lumps.