Free energy calculations for rings and chains formed by dipolar hard spheres.

We employ a method based on Monte Carlo grand-canonical simulations to precisely calculate partition functions of non-interacting chains and rings formed by dipolar hard spheres (DHS) at low temperature. The extended low temperature region offered by such cluster calculations, compared to what had been previously achieved with standard simulations, opens up the possibility of exploring a part of the DHS phase diagram which was inaccessible before. The reported results offer the unique opportunity of verifying well-established theoretical models based on the ideal gas of cluster approximation in order to clarify their range of validity. They also provide the basis for future studies in which cluster-cluster interactions will be included.

Temperature-induced structural transitions in self-assembling magnetic nanocolloids.

With the help of a unique combination of density functional theory and computer simulations, we discover two possible scenarios, depending on concentration, for the hierarchical self-assembly of magnetic nanoparticles on cooling. We show that typically considered low temperature clusters, i.e. defect-free chains and rings, merge into more complex branched structures through only three types of defects: four-way X junctions, three-way Y junctions and two-way Z junctions. Our accurate calculations reveal the predominance of weakly magnetically responsive rings cross-linked by X defects at the lowest temperatures. We thus provide a strategy to fine-tune magnetic and thermodynamic responses of magnetic nanocolloids to be used in medical and microfluidics applications.

Locally advanced penile carcinoma: classic emasculation or testis-sparing surgery?

The study evaluates the clinical and pathological findings of 16 patients with locally advanced penile carcinoma (PC) submitted to emasculation, and discusses questions related to the usefulness of bilateral orchiectomy.

Between 1999 and 2010, 172 patients with PC were treated. Sixteen (9%) underwent emasculation. Data were retrieved from the institution's database including age, ethnicity, date of surgery, residential setting, level of schooling, time to diagnosis, type of reconstruction, complications, tumor stage and grade, vascular and perineural invasion along with invasion of corpus cavernosum, corpus spongiosum, testicles, scrotum and urethra.

A total of 16 patients (average: 63.1 years) with locally advanced PC were included. All were illiterate or semiliterate rural dwellers and 87% were white. The time to diagnosis was 8-12 months. The mean follow-up time was 31.9 months (1-119). By the time of the last follow-up, only seven patients (43.75%) were alive. Tumors were pT4 (n = 6), pT3 (n = 8), pT2 (n = 2), Grade I (n = 5) and Grade II (n = 11). The histopathological examination revealed invasion of the urethra (n = 13), scrotum (n = 5) and testicles (n = 1). The surgical margin was positive in one patient. Six patients (37.5%) had vascular invasion and 11 (68.7%) had perineural invasion. Currently, only one of the former is alive.

The finding of focal microscopic testicular infiltration in only one of 32 testicles, even in the presence of clinically apparent scrotal invasion, suggests that emasculation without bilateral orchiectomy is a safe treatment option for patients with locally advanced PC. .

Locally advanced penile carcinoma: classic emasculation or testis-sparing surgery?

PURPOSE: The study evaluates the clinical and pathological findings of 16 patients with locally advanced penile carcinoma (PC) submitted to emasculation, and discusses questions related to the usefulness of bilateral orchiectomy. MATERIALS AND METHODS: Between 1999 and 2010, 172 patients with PC were treated. Sixteen (9 %) underwent emasculation. Data were retrieved from the institution's database including age, ethnicity, date of surgery, residential setting, level of schooling, time to diagnosis, type of reconstruction, complications, tumor stage and grade, vascular and perineural invasion along with invasion of corpus cavernosum, corpus spongiosum, testicles, scrotum and urethra. RESULTS: A total of 16 patients (average: 63.1 years) with locally advanced PC were included. All were illiterate or semiliterate rural dwellers and 87% were white. The time to diagnosis was 8-12 months. The mean follow-up time was 31.9 months (1-119). By the time of the last follow-up, only seven patients (43.75%) were alive. Tumors were pT4 (n = 6), pT3 (n = 8), pT2 (n = 2), Grade I (n = 5) and Grade II (n = 11). The histopathological examination revealed invasion of the urethra (n = 13), scrotum (n = 5) and testicles (n = 1). The surgical margin was positive in one patient. Six patients (37.5%) had vascular invasion and 11 (68.7%) had perineural invasion. Currently, only one of the former is alive. CONCLUSIONS: The finding of focal microscopic testicular infiltration in only one of 32 testicles, even in the presence of clinically apparent scrotal invasion, suggests that emasculation without bilateral orchiectomy is a safe treatment option for patients with locally advanced PC.

The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.

PURPOSE: Penile carcinoma is a common disease in northeast Brazil. This paper shows the results of the use of isolated gamma probe and discusses the incidence of false negative rates. MATERIALS AND METHODS: From July 2000 to September 2003, 27 newly diagnosed penile carcinoma patients (T1, T2, N0) were included in this prospective study. The isolated gamma probe technique uses the sodium phytate technetium as a tracer and inguinal scanning with probe and after identified the lymph node it is removed. Lymphadenectomies were performed for positive inguinal lymph nodes metastasis. RESULTS: There were 27 patients (mean age 59.6). Follow up was 37 months. Patients from country were 72% and illiterate or semi-illiterate were 56.7%. The tumors were mostly located in the glans (81.4%). They were T1, 52 % and T2, 48 %. 81.4% of the patients underwent partial penectomy, and 18.6% underwent postectomy and excision with wide margins. In 48% of the patients, the highest radioactive count rate was located on the left side, while in 41% was located on the right side. Only one patient had a positive pathological lymph node metastasis at the moment of the surgery. Additionally 3 patients became inguinal lymph node positive at the follow up. This date yielded a sensibility rate of 25% and a false-negative rate of 42.8%. CONCLUSION: Isolated gamma probe technique for sentinel node penile carcinoma has a very low sensibility and a high false negative rate. Therefore it is highly advisable the addition of others methods such as lymphoscintigraphy, vital blue, ultrasonography and so on. The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.

The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable

PURPOSE: Penile carcinoma is a common disease in northeast Brazil. This paper shows the results of the use of isolated gamma probe and discusses the incidence of false negative rates. MATERIALS AND METHODS: From July 2000 to September 2003, 27 newly diagnosed penile carcinoma patients (T1, T2, N0) were included in this prospective study. The isolated gamma probe technique uses the sodium phytate technetium as a tracer and inguinal scanning with probe and after identified the lymph node it is removed. Lymphadenectomies were performed for positive inguinal lymph nodes metastasis. RESULTS: There were 27 patients (mean age 59.6). Follow up was 37 months. Patients from country were 72 percent and illiterate or semi-illiterate were 56.7 percent. The tumors were mostly located in the glans (81.4 percent). They were T1, 52 percent and T2, 48 percent. 81.4 percent of the patients underwent partial penectomy, and 18.6 percent underwent postectomy and excision with wide margins. In 48 percent of the patients, the highest radioactive count rate was located on the left side, while in 41 percent was located on the right side. Only one patient had a positive pathological lymph node metastasis at the moment of the surgery. Additionally 3 patients became inguinal lymph node positive at the follow up. This date yielded a sensibility rate of 25 percent and a false-negative rate of 42.8 percent. CONCLUSION: Isolated gamma probe technique for sentinel node penile carcinoma has a very low sensibility and a high false negative rate. Therefore it is highly advisable the addition of others methods such as lymphoscintigraphy, vital blue, ultrasonography and so on. The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.

Aggressive vaginal angiomyxoma mimicking urethral tumor.

This is a case report of a 32-year-old female patient with a neoplasia mimicking a urethral tumor. Following anterior pelvic exanteration, vulvectomy, bilateral inguinal lymphadenectomy, the pathological study established the diagnosis of aggressive vaginal angiomyxoma, CD-34 labeled.

Aggressive vaginal angiomyxoma mimicking urethral tumor

This is a case report of a 32-year-old female patient with a neoplasia mimicking a urethral tumor. Following anterior pelvic exanteration, vulvectomy, bilateral inguinal lymphadenectomy, the pathological study established the diagnosis of aggressive vaginal angiomyxoma, CD-34 labeled.