The role of CC chemokine receptor 5 (CCR5) in islet allograft rejection

Chemokines are important regulators in the development, differentiation, and anatomic location of leukocytes. CC chemokine receptor 5 (CCR5) is expressed preferentially by CD4(+) T helper 1 (Th1) cells. We sought to determine the role of CCR5 in islet allograft rejection in a streptozotocin-induced diabetic mouse model. BALB/c islet allografts transplanted into CCR5(-/-) (C57BL/6) recipients survived significantly longer (mean survival time, 38 +/- 8 days) compared with those transplanted into wild-type control mice (10 +/- 2 days; P < 0.0001). Twenty percent of islet allografts in CCR5(-/-) animals without other treatment survived >90 days. In CCR5(-/-) mice, intragraft mRNA expression of interleukin-4 and -5 was increased, whereas that of interferon-gamma was decreased, corresponding to a Th2 pattern of T-cell activation in the target tissues compared with a Th1 pattern observed in controls. A similar Th2 response pattern was also observed in the periphery (splenocytes responding to donor cells) by enzyme-linked immunosorbent spot assay. We conclude that CCR5 plays an important role in orchestrating the Th1 immune response leading to islet allograft rejection. Targeting this chemokine receptor, therefore, may provide a clinically useful strategy to prevent islet allograft rejection.     

Organ Donation: Cross-Sectional Survey of Knowledge and Personal Views of Brazilian Medical Students and Physicians

Objective

To assess the knowledge, attitudes, and behavior associated with cadaver organ donation and transplantation among medical students and physicians.

Patients and Methods

We randomly selected 350 medical students, 150 physicians, and 150 intensive care unit physicians. Each completed a questionnaire consisting of 9 self-administered items, from which we gathered data about their knowledge about brain death and criteria for the diagnosis of brain death; their hypothetical behaviors, assuming willingness to donate their own or their family's organs; their trust in physicians; and their confidence in a diagnosis of brain death made by physicians.

Results

We observed that knowledge about brain death increased with medical education level; the best results were noted in intensive care unit physicians. Agreement to transplant organs from brain-dead donors (odds ratio [OR], 4.58), confidence in brain-death diagnosis by physicians (OR, 2.17), and knowledge about criteria for the diagnosis of brain death (OR, 2.26) were predictors of willingness to donate one's own organs.

Conclusion

Enhanced medical knowledge of and involvement in donation are needed to achieve cadaver organ donation.     

Laparoscopically assisted esophagectomy and colon interposition for esophageal replacement in children: preliminary results of a novel technique

Background

Colonic interposition is one of the surgical options in children when esophageal replacement is necessary, especially when the stomach is not suitable as a conduit. Conventional open surgery and blind mediastinal dissections present reasonable morbidity, which can be reduced by videosurgery. The authors present novel techniques and the preliminary results of the first series of laparoscopically assisted esophagectomies and colonic interpositions (LECIN) in children.

Methods

Five children aged 19 months to 4 years underwent LECIN. Indications were complicated esophageal atresia and severe caustic esophagitis. The patients were operated on laparoscopically using 3 ports, including the gastrostomy site. Transhiatal esophagectomy was carried out, followed by pyloroplasty and mobilization of the transverse colon maintaining a double blood supply from the left pedicle. The stomach at the gastrostomy site was freed and closed in 3 cases. The colon was exteriorized through this 2- to 3-cm site or through the umbilicus, and the conduit was fashioned extracorporeally, including the colocolic and gastrocolic anastomosis. The colon was pulled up along the retromediastinal tunnel for the coloesophageal anastomosis through a cervical incision.

Results

Operative times ranged from 3 to 4.3 hours; there were no conversions and no complications related to laparoscopy. There were no cardiorespiratory problems, and 4 were extubated immediately after operation. Feedings could be started by day 3 to 4. Postoperative complications included atelectasis (1), pneumonia (1), and cervical stenosis because of persistent fibrotic esophagus, requiring cervical revision (1). One needed dilatations for mild dysphagia. After a follow-up period of 10 to 29 months, all patients are asymptomatic, gaining weight, and feeding well.

Conclusions

These preliminary data suggest that LECIN is feasible and can be safely performed with very low morbidity in children. Further studies with larger series and follow-up are expected.     

Prevalence and Severity of Sleep Apnea in a Group of Morbidly Obese Patients

Background Obesity is the most important risk factor for obstructive sleep apnea. It is estimated that 70% of sleep apnea patients are obese. In the morbidly obese, the prevalence may reach 80% in men and 50% in women. The aim of this study was to determine the prevalence and severity of sleep apnea in a group of morbidly obese patients, leading to bariatric surgery. Methods In a cross-sectional study developed in Bahia, northeastern Brazil. 108 patients (78 women and 30 men) from the Obesity Treatment and Surgery Center - “Núcleo de Tratamento e Cirurgia da Obesidade” underwent standard polysomnography. Patients with an apnea-hypopnea index (AHI) ≥ 5 events/hour were considered apneic. Results Mean ± SD for age and BMI were 37.1 ± 10.2 years and 45.2 ± 5.4 kg/m2, respectively. The calculated AHI ranged widely from 2.5 to 128.9 events/hour. Sleep apnea was detected in 93.6% of the sample, wherein 35.2% had mild, 30.6% moderate and 27.8% severe apnea. Oxyhemoglobin desaturation was directly related to the AHI and was more severe in men. Conclusion There was a high frequency of sleep apnea in this group of morbidly obese patients, for whom it was very important to request polysomnography, thus enabling therapeutic management and prognostication.     

Effect of bilateral median nerve excision on sciatic functional index in rat: an applicable animal model for autologous nerve grafting

Autologous nerve graft is still the treatment of choice in peripheral nerve injury when end-to-end nerve repair is not possible. The sciatic nerve is the most widely used nerve in rat experimental studies. To assess the possibility of using the rat median nerve as a delayed animal autologous nerve graft model in nerve regeneration studies, the effect of median nerve excision on the sciatic functional index (SFI) was evaluated. Thirty rats were distributed into three equal groups: in the sciatic and median nerve excision (SMNE) group, 10 mm of the right sciatic nerve was excised and 5 mm of both median nerves were excised a week later; in the median nerve excision (MNE) group, 5 mm of both median nerves were excised (both sciatic nerves remained intact); in the control group, no intervention was performed. SFI was calculated before and after each intervention. There was no significant difference between mean SFI values calculated before and after median nerve excision in SMNE (-86.8 versus -88.4, P = 0.61) and MNE groups (-3.9 versus -3.3, P = 0.93). Therefore, it may be suggested that median nerve excision does not affect SFI measurements in intact and/or completely injured sciatic nerve, which may propose the median nerve as an autologous donor nerve graft model in rats.