Two distinct types of depolarizing afterpotentials are differentially expressed in stellate and pyramidal‐like neurons of entorhinal‐cortex layer II

Two types of principal neurons, stellate cells and pyramidal‐like cells, are found in medial entorhinal‐cortex (mEC) layer II, and are believed to represent two distinct channels of information processing and transmission in the entorhinal cortex–hippocampus network. In this study, we found that depolarizing afterpotentials (DAPs) that follow single action potentials (APs) evoked from various levels of holding membrane voltage (V_h) show distinct properties in the two cells types. In both, an evident DAP followed the AP at near‐threshold V_h levels, and was accompanied by an enhancement of excitability and spike‐timing precision. This DAP was sensitive to voltage‐gated Na⁺‐channel block with TTx, but not to partial removal of extracellular Ca²⁺. Application of 5‐μM anandamide, which inhibited the resurgent and persistent Na⁺‐current components in a relatively selective way, significantly reduced the amplitude of this particular DAP while exerting poor effects on the foregoing AP. In the presence of background hyperpolarization, DAPs showed an opposite behavior in the two cell types, as in stellate cells they became even more prominent, whereas in pyramidal‐like cells their amplitude was markedly reduced. The DAP observed in stellate cells under this condition was strongly inhibited by partial extracellular‐Ca²⁺ removal, and was sensitive to the low‐voltage‐activated Ca²⁺‐channel blocker, NNC55‐0396. This Ca²⁺ dependence was not observed in the residual DAP evoked in pyramidal‐like cells from likewise negative V_h levels. These results demonstrate that two distinct mechanism of DAP generation operate in mEC layer‐II neurons, one Na⁺‐dependent and active at near‐threshold V_h levels in both stellate and‐pyramidal‐like cells, the other Ca²⁺‐dependent and only expressed by stellate cells in the presence of background membrane hyperpolarization. © 2015 Wiley Periodicals, Inc.     

Ventricular pacemaker lead in the left hemithorax: Mechanisms and evidence‐based management of a late‐onset hazardous complication

Late‐onset migration of pacing leads in the left hemithorax is a rare but potentially life‐threatening complication. Radiological examinations are required to detect any involvement of either left ventricle or lung parenchyma, prompting immediate surgical extraction in this setting. Identification of high‐risk patients is mandatory to prevent this complex iatrogenic complication.     

Surgical approach of complicated diverticulitis with colovesical fistula: technical note in a particular condition

Background: Diverticular disease of the colon is common in the Western world. With the first episode of diverticulitis, most patients will benefit from medical therapy, but in 10% to 20% of cases some complications will develop, such as intra-abdominal abscesses, obstructions, fistulas. In these conditions it is important to define the most appropriate surgical approach. Discussion: The management of diverticular disease has been successful owing to the advances in diagnostic methods, intensive care and surgical experience, but there is debate about the best treatment for some conditions. Fistulas complicating diverticulitis are the result of a localized perforation into adjacent viscera. In particular, the connection between the colon and the urinary tract is a serious anatomical abnormality that must be urgently corrected before a serious urinary infection results. Indications, timing and surgical procedures are determined by the severity of the disease and the patient’s general condition. Summary: Diverticular disease can lead to many complications. One of the most difficult to correct is an internal fistula, such as a colo-vesical fistula. The correct approach in cases where the disorder is clinically suspected has always been controversial, and the guidelines for sigmoid diverticulitis have not established the most appropriate method for diagnosis and treatment. At present, the surgical strategy for these cases requires interruption of the fistula and resection to remove the inflamed colonic segment, with or without primary anastomosis, focusing attention on the construction of the anastomosis to well vascularized and anatomically healthy tissues. It is clear, therefore, that establishing guidelines is difficult, because many pathological situations may be related to diverticulitis, and so, as our experience shows, the surgical approach has to be tailored to the patient’s general and local condition.     

Stump nerve signals during transcranial magnetic motor cortex stimulation recorded in an amputee via longitudinal intrafascicular electrodes

Do central and peripheral motor pathways associated with an amputated limb retain at least some functions over periods of years? This problem could be addressed by evaluating the response patterns of nerve signals from peripheral motor fibers during transcranial magnetic stimulation (TMS) of corticospinal tracts. The aim of this study was to record for the first time TMS-related responses from the nerves of a left arm stump of an amputee via intrafascicular longitudinal flexible multi-electrodes (tfLIFE4) implanted for a prosthetic hand control. After tfLIFE4 implant in the stump median and ulnar nerves, TMS impulses of increasing intensity were delivered to the contralateral motor cortex while tfLIFE4 recordings were carried out. Combining TMS of increasing intensity and tfLIFE4 electrodes recordings, motor nerve activity possibly related to the missing limb motor control and selectively triggered by brain stimulation without significant electromyographic contamination was identified. These findings are entirely original and indicate that tfLIFE4 signals are clearly driven from M1 stimulation, therefore witnessing the presence in the stump nerves of viable motor signals from the CNS possibly useful for artificial prosthesis control.     

Optical coherence tomography accurately identifies intermediate atherosclerotic lesions--an in vivo evaluation in the rabbit carotid artery

OBJECTIVE: We tested the ability of optical coherence tomography (OCT) to identify very early stages of atherosclerosis in vivo. METHODS: Twelve New Zealand white male rabbits (weight 3.5-4.0 kg) underwent perivascular electrical injury of the common carotid arteries, and were then fed a cholesterol-rich diet. At 43+/-16 (range 27-63) days after injury, arteries were imaged by OCT, then rabbits were euthanized and vessels processed for histology. RESULTS: A total of 14 carotid arteries were imaged by OCT and histology; 22 atherosclerotic lesions were identified, 16 (73%) occurring at the site of the electrical injury. At histology, 4 lesions were defined as Stary type I (isolated macrophages), 8 as type II (intracellular lipid accumulations), and 10 as type III (small extracellular lipid pools). No advanced (> or =type IV) lesions were documented. OCT failed to detect any type I lesions, but correctly defined a minority (2/8, 25%) of type II lesions and the majority (8/10, 80%) of type III lesions. For type III lesions, sensitivity, specificity and diagnostic accuracy of OCT were 80%, 95%, and 95%, respectively. CONCLUSIONS: OCT can accurately detect intermediate (type-III) atherosclerotic lesions in vivo, but still fails to identify earlier stages of atherosclerosis.     

Utility of week-4 viral response to tailor treatment duration in hepatitis C virus genotype 3/HIV co-infected patients

OBJECTIVE: To investigate the utility of a week-4 virological response for sustained response prediction in hepatitis C virus (HCV) genotype 3/HIV-co-infected patients treated with interferon and ribavirin for 24 weeks. METHODS: Using a real-time polymerase chain reaction-based quantitative assay (COBAS AmpliPrep-COBAS-TaqMan 48; Roche Diagnostics) we retrospectively analysed samples obtained at baseline and weeks 4 and 12 from a subset of 35 HCV genotype 3-HIV co-infected patients enrolled in a randomized comparative trial of peginterferon alpha-2b versus interferon alpha-2b both in combination with ribavirin. RESULTS: In an intention-to-treat analysis, 78% of patients treated with peginterferon and 53% of those receiving standard interferon achieved a sustained virological response (SVR) Overall, at 4 weeks, 49% of patients had HCV RNA < 50 IU/ml and 63% had < 600 IU/ml. Of these rapid responders 88 and 86% achieved a SVR, respectively, with only one patient relapsing among end-of-treatment responders. In contrast, only 44 and 31% of patients with a week-4 HCV RNA >or= 50 or >or= 600 IU/ml achieved an SVR, respectively, with relapse rates of 33 and 50%, respectively. In multivariate logistic regression analysis a serum HCV RNA level below 600 IU/ml at week 4 was the strongest independent predictor of SVR (odds ratio, 11.3; 95% confidence interval, 1.7 to 75.0; P = 0.012). CONCLUSION: Monitoring early viral response may be useful to tailor the duration of treatment among patients with HCV genotype 3/HIV-co-infection. Patients whose HCV RNA falls below 600 IU/ml at 4 weeks are at low risk of relapse after 24 weeks of combination therapy.     

Rapid maxillary expansion in children with obstructive sleep apnea syndrome: 12-month follow-up

OBJECTIVES: To assess the outcome of rapid maxillary expansion in the treatment of obstructive sleep apnea syndrome (OSAS) in children, we studied 16 patients (mean age 6.6+/-2.0; 9 males) with dental malocclusion, a body mass index < or =85 percentile, and OSAS confirmed by polysomnography. METHODS: At baseline and after the trial, all patients underwent physical examination, standard polysomnography and orthodontic assessment. The Brouillette questionnaire investigating symptoms of OSA was administered to parents before and during the trial to assess the clinical severity of their sleep-disordered breathing. Two treated patients were lost to follow-up and excluded from the final study. RESULTS: In the 14 treated subjects who completed the study and follow-up, polysomnography showed a significant decrease in the apnea-hypopnea index (p=0.005), hypopnea obstructive index (p=0.002) and arousal index (p=0.001). Questionnaire responses before and after treatment showed a significant decrease in the severity of symptoms. CONCLUSION: A rapid maxillary expander is an effective appliance for treating children with OSAS.     

Role of axillary ultrasound examination in the selection of breast cancer patients for sentinel node biopsy

BACKGROUND: Sentinel node biopsy (SNB) is a time-consuming procedure that can be avoided in presence of axillary metastases. The aim of this study was to assess the accuracy of ultrasound scan (US) in the prediction of axillary nodes status in patients scheduled for SNB. METHODS: Axillary US was performed and when feasible, a core biopsy of suspicious nodes was taken. The nodal status as assessed by US and/or core biopsy was compared with final histology. RESULTS: Of the 132 patients enrolled, 31 (23.5%) had suspicious axillary nodes according to US; 19 (61.3%) were true positive, whereas 12 cases (38.7%) were not. In 14 of 31 suspicious cases an US-guided core-biopsy was taken, which in 11 of 14 cases (78.5%) confirmed the neoplastic involvement. Overall, core biopsy of the nodes correctly predicted the final histology in 13 of 14 cases (92.8%). CONCLUSIONS: The US of axillary nodes, possibly associated with core biopsy, improved the preoperative evaluation of breast cancer patients scheduled for SNB.     

Laparoscopic Sleeve Gastrectomy—Volume and Pressure Assessment

BACKGROUND: Aiming to clarify the mechanism of weight loss after the restrictive bariatric procedure of sleeve gastrectomy (LSG), the volumes and pressures of the stomach, of the removed part, and of the remaining sleeve were measured in 20 morbidly obese patients. METHODS: The technique used consisted of occlusion of the pylorus with a laparoscopic clamp and of the gastroesophageal junction with a special orogastric tube connected to a manometer. Instillation of methylene-blue-colored saline via the tube was continued until the intraluminal pressure increased sharply, or the inflated stomach reached 2,000 cc. After recording of measurements, LSG was performed. RESULTS: Mean volume of the entire stomach was 1,553 cc (600-2,000 cc) and that of the sleeve 129 cc (90-220 cc), i.e., 10% (4-17%) and that of the removed stomach was 795 cc (400-1,500 cc). The mean basal intragastric pressure of the whole stomach after insufflations of the abdominal cavity with CO(2) to 15 mmHg was 19 mmHg (11-26 mmHg); after occlusion and filling with saline it was 34 mmHg (21-45 mmHg). In the sleeved stomach, mean basal pressure was similar 18 mmHg (6-28 mmHg); when filled with saline, pressure rose to 43 mmHg (32-58 mmHg). The removed stomach had a mean pressure of 26 mmHg (12-47 mmHg). There were no postoperative complications and no mortality. CONCLUSIONS: The notably higher pressure in the sleeve, reflecting its markedly lesser distensibility compared to that of the whole stomach and of the removed fundus, indicates that this may be an important element in the mechanism of weight loss.