Role of afferent renal nerves in spontaneous hypertension in rats

In the present study we examined sympathetic function and baroreceptor reflex sensitivity in adult spontaneously hypertensive rats (SHR) after a selective transection of afferent renal nerves in the prehypertensive and established phases of hypertension. Renal deafferentation performed between 3 and 4 weeks after birth did not influence the course of the development of high blood pressure when compared with sham-operated rats. Mean arterial pressure, heart rate, and plasma norepinephrine concentrations were similar in both groups when measured at 13 weeks after renal deafferentation. However, blood pressure responses to ganglionic blockade with hexamethonium were significantly reduced in the renal deafferented SHR. Baroreceptor reflex sensitivity, assessed by heart rate responses to blood pressure changes induced by phenylephrine and nitroprusside, was significantly enhanced in these rats. When renal deafferentation was performed in adult SHR with established hypertension, mean arterial pressure decreased slightly but significantly by 5%. Heart rate, plasma norepinephrine concentrations, and responses to hexamethonium were not affected by this procedure. However, in the renal deafferented adult SHR, heart rate responses to phenylephrine but not to nitroprusside were significantly increased. Thus, in contrast to efferent renal nerves, afferent renal nerves do not play an important role in the development and maintenance of high blood pressure in SHR, but may contribute to the mechanisms that alter sympathetic function and baroreceptor reflex sensitivity in SHR during the development of hypertension.     

Parcellations and hemispheric asymmetries of human cerebral cortex analyzed on surface-based atlases

We report on surface-based analyses that enhance our understanding of human cortical organization, including its convolutions and its parcellation into many distinct areas. The surface area of human neocortex averages 973 cm(2) per hemisphere, based on cortical midthickness surfaces of 2 cohorts of subjects. We implemented a method to register individual subjects to a hybrid version of the FreeSurfer "fsaverage" atlas whose left and right hemispheres are in precise geographic correspondence. Cortical folding patterns in the resultant population-average "fs_LR" midthickness surfaces are remarkably similar in the left and right hemispheres, even in regions showing significant asymmetry in 3D position. Both hemispheres are equal in average surface area, but hotspots of surface area asymmetry are present in the Sylvian Fissure and elsewhere, together with a broad pattern of asymmetries that are significant though small in magnitude. Multiple cortical parcellation schemes registered to the human atlas provide valuable reference data sets for comparisons with other studies. Identified cortical areas vary in size by more than 2 orders of magnitude. The total number of human neocortical areas is estimated to be ～150 to 200 areas per hemisphere, which is modestly larger than a recent estimate for the macaque.     

High Lymph Node Yield is Related to Microsatellite Instability in Colon Cancer

Background

Lymph node (LN) yield in colon cancer resection specimens is an important indicator of treatment quality and has especially in early-stage patients therapeutic implications. However, underlying disease mechanisms, such as microsatellite instability (MSI), may also influence LN yield, as MSI tumors are known to exhibit more prominent lymphocytic antitumor reactions. The aim of the present study was to investigate the association of LN yield, MSI status, and recurrence rate in colon cancer.

Methods

Clinicopathological data and tumor samples were collected from 332 stage II and III colon cancer patients. DNA was isolated and PCR-based MSI analysis performed. LN yield was defined as “high” when 10 or more LNs were retrieved and “low” in case of fewer than 10 LNs.

Results

Tumors with high LN yield were significantly associated with the MSI phenotype (high LN yield: 26.3% MSI tumors vs low LN yield: 15.1% MSI tumors; P = .01), mainly in stage III disease. Stage II patients with high LN yield had a lower recurrence rate compared with those with low LN yield. Patients with MSI tumors tended to develop fewer recurrences compared with those with MSS tumors, mainly in stage II disease.

Conclusions

In the present study, high LN yield was associated with MSI tumors, mainly in stage III patients. Besides adequate surgery and pathology, high LN yield is possibly a feature caused by biologic behavior of MSI tumors.     

Decision support system for the operating room rescheduling problem

Due to surgery duration variability and arrivals of emergency surgeries, the planned Operating Room (OR) schedule is disrupted throughout the day which may lead to a change in the start time of the elective surgeries. These changes may result in undesirable situations for patients, wards or other involved departments, and therefore, the OR schedule has to be adjusted. In this paper, we develop a decision support system (DSS) which assists the OR manager in this decision by providing the three best adjusted OR schedules. The system considers the preferences of all involved stakeholders and only evaluates the OR schedules that satisfy the imposed resource constraints. The decision rules used for this system are based on a thorough analysis of the OR rescheduling problem. We model this problem as an Integer Linear Program (ILP) which objective is to minimize the deviation from the preferences of the considered stakeholders. By applying this ILP to instances from practice, we determined that the given preferences mainly lead to (i) shifting a surgery and (ii) scheduling a break between two surgeries. By using these changes in the DSS, the performed simulation study shows that less surgeries are canceled and patients and wards are more satisfied, but also that the perceived workload of several departments increases to compensate this. The system can also be used to judge the acceptability of a proposed initial OR schedule.     

Total parenteral nutrition after surgery rapidly increases serum leptin levels

OBJECTIVE: In humans, leptin is regulated by long-term changes in energy intake. However, short-term regulation of serum leptin by nutrients has been difficult to show. The aim of this study was to investigate whether short periods of fasting and stress sensitise the leptin response to nutrients. SUBJECTS AND EXPERIMENTAL PROTOCOL: Fourteen patients of normal weight undergoing elective open cholecystectomy were randomised into two groups. One group received saline infusion during surgery and for 24 h postoperatively. The other group also received saline during the surgical procedure, but total parenteral nutrition (TPN) was started immediately after surgery. Blood samples were drawn before as well as 2, 4, 8, 16, and 24 h after the start of surgery to determine the serum levels of leptin and other hormones. RESULTS: Postoperative TPN induced a significant rise in serum leptin within 6 h, reaching a more than fourfold increase within 14 h (P<0.001). Serum glucose and insulin levels increased within 2 h. Growth hormone and IGF-1 serum levels also increased significantly in the group receiving TPN. Serum cortisol levels increased postoperatively in both groups, which may explain why no significant reduction in serum leptin was observed in the group receiving saline. Free tri-iodothyronine (T3) decreased in both groups, while catecholamines were similar in the groups. CONCLUSION: During fasting and surgical stress, nutrients rapidly increased the serum leptin levels in humans in a manner similar to that previously reported in rodents. This may be mediated by increases in serum glucose, insulin and cortisol.     

Begriff und Bedeutung des photischen Dunkels

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Hemiplegie bei Endarteriitis obliterans

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