Tyrosine hydroxylase immunoreactivity as indicator of sympathetic activity: simultaneous evaluation in different tissues of hypertensive rats

Burgi K, Cavalleri MT, Alves AS, Britto LRG, Antunes VR, Michelini LC. Tyrosine hydroxylase immunoreactivity as indicator of sympathetic activity: simultaneous evaluation in different tissues of hypertensive rats. Am J Physiol Regul Integr Comp Physiol 300: R264-R271, 2011. First published December 9, 2010; doi: 10.1152/ajpregu.00687.2009.-Vasomotor control by the sympathetic nervous system presents substantial heterogeneity within different tissues, providing appropriate homeostatic responses to maintain basal/stimulated cardiovascular function both at normal and pathological conditions. The availability of a reproducible technique for simultaneous measurement of sympathetic drive to different tissues is of great interest to uncover regional patterns of sympathetic nerve activity (SNA). We propose the association of tyrosine hydroxylase immunoreactivity (THir) with image analysis to quantify norepinephrine (NE) content within nerve terminals in arteries/arterioles as a good index for regional sympathetic outflow. THir was measured in fixed arterioles of kidney, heart, and skeletal muscle of WistarKyoto rats (WKY) and spontaneously hypertensive rats (SHR) (123 +/- 2 and 181 +/- 4 mmHg, 300 +/- 8 and 352 +/- 8 beats/min, respectively). There was a differential THir distribution in both groups: higher THir was observed in the kidney and skeletal muscle (similar to 3-4-fold vs. heart arterioles) of WKY; in SHR, THir was increased in the kidney and heart (2.4- and 5.3-fold vs. WKY, respectively) with no change in the skeletal muscle arterioles. Observed THir changes were confirmed by either: 1) determination of NE content (high-performance liquid chromatography) in fresh tissues (SHR vs. WKY): +34% and +17% in kidney and heart, respectively, with no change in the skeletal muscle; 2) direct recording of renal (RSNA) and lumbar SNA (LSNA) in anesthetized rats, showing increased RSNA but unchanged LSNA in SHR vs. WKY. THir in skeletal muscle arterioles, NE content in femoral artery, and LSNA were simultaneously reduced by exercise training in the WKY group. Results indicate that THir is a valuable technique to simultaneously evaluate regional patterns of sympathetic activity.

Alteration of purinergic P2X(4) and P2X(7) receptor expression in rats with temporal-lobe epilepsy induced by pilocarpine

Although ATP and P2X receptor activity have been lately associated with epilepsy, little is known regarding their exact roles in epileptogenesis. Temporal-lobe epilepsy (TLE) in rat was induced by pilocarpine in order to study changes of hippocampal P2X(2), P2X(4) and P2X(7) receptor expression during acute, latent or chronic phases of epilepsy. During acute and chronic phases increased P2X(7) receptor expression was principally observed in glial cells and glutamatergic nerve terminals, suggesting participation of this receptor in the activation of inflammatory and excitotoxic processes during epileptogenesis. No significant alterations of hippocampal P2X(2) and P2X(4) receptor expression was noted during the acute or latent phase when compared to the control group, indicating that these receptors are not directly involved with the initiation of epilepsy. However, the reduction of hippocampal P2X(4) receptor immunostaining in the chronic phase could reflect neuronal toss or decreased GABAergic signaling. (C) 2008 Elsevier B.V. All rights reserved.

Solving the Vehicle Routing Problem with Genetic ALgorithm and Simulated Annealing

This Thesis Work will concentrate on a very interesting problem, the Vehicle Routing Problem (VRP). In this problem, customers or cities have to be visited and packages have to be transported to each of them, starting from a basis point on the map. The goal is to solve the transportation problem, to be able to deliver the packages-on time for the customers,-enough package for each Customer,-using the available resources- and – of course - to be so effective as it is possible.Although this problem seems to be very easy to solve with a small number of cities or customers, it is not. In this problem the algorithm have to face with several constraints, for example opening hours, package delivery times, truck capacities, etc. This makes this problem a so called Multi Constraint Optimization Problem (MCOP). What’s more, this problem is intractable with current amount of computational power which is available for most of us. As the number of customers grow, the calculations to be done grows exponential fast, because all constraints have to be solved for each customers and it should not be forgotten that the goal is to find a solution, what is best enough, before the time for the calculation is up. This problem is introduced in the first chapter: form its basics, the Traveling Salesman Problem, using some theoretical and mathematical background it is shown, why is it so hard to optimize this problem, and although it is so hard, and there is no best algorithm known for huge number of customers, why is it a worth to deal with it. Just think about a huge transportation company with ten thousands of trucks, millions of customers: how much money could be saved if we would know the optimal path for all our packages.Although there is no best algorithm is known for this kind of optimization problems, we are trying to give an acceptable solution for it in the second and third chapter, where two algorithms are described: the Genetic Algorithm and the Simulated Annealing. Both of them are based on obtaining the processes of nature and material science. These algorithms will hardly ever be able to find the best solution for the problem, but they are able to give a very good solution in special cases within acceptable calculation time.In these chapters (2nd and 3rd) the Genetic Algorithm and Simulated Annealing is described in details, from their basis in the “real world” through their terminology and finally the basic implementation of them. The work will put a stress on the limits of these algorithms, their advantages and disadvantages, and also the comparison of them to each other.Finally, after all of these theories are shown, a simulation will be executed on an artificial environment of the VRP, with both Simulated Annealing and Genetic Algorithm. They will both solve the same problem in the same environment and are going to be compared to each other. The environment and the implementation are also described here, so as the test results obtained.Finally the possible improvements of these algorithms are discussed, and the work will try to answer the “big” question, “Which algorithm is better?”, if this question even exists.

Simulation of Sawmill Yard Operations Using Software Agents

Bergkvist insjön AB is a sawmill yard which is capable of producing 350,000 cubic meter of timber every year this requires lot of internal resources. Sawmill operations can be classified as unloading, sorting, storage and production of timber. In the company we have trucks arriving at random they have to be unloaded and sent back at the earliest to avoid queuing up of trucks creating a problem for truck owners. The sawmill yard has to operate with two log stackers that does several tasks including transporting the logs from trucks to measurement station where the logs will be sorted into classes and dropped into pockets from pockets to the sorted timber yard where they are stored and finally from there to sawmill for final processing. The main issue that needs to be answered here is the lining up trucks that are waiting to be unload, creating a problem for both sawmill as well as the truck owners and given huge production volume, it is certain that handling of resources is top priority. A key challenge in handling of resources would be unloading of trucks and finding a way to optimize internal resources.To address this problem i have experimented on different ways of using internal resources, i have designed different cases, in case 1 we have both the log stackers working on sawmill and measurement station. The main objective of having this case is to make sawmill and measurement station to work all the time. Then in case 2, i have divided the work between both the log stackers, one log stacker will be working on sawmill and pocket_control and second log stacker will be working on measurement station and truck. Then in case 3 we have only one log stacker working on all the agents, this case was designed to reduce cost of production, as the experiment cannot be done in real-time due to operational cost, for this purpose simulation is used, preliminary investigation into simulation results suggested that case 2 is the best option has it reduced waiting time of trucks considerably when compared with other cases and it showed 50% increase in optimizing internal resources.

Separoh jalan (halfway)

The sign that marked the exact mid-point of the journey between Launceston and Hobart was located at the far side of the road in one of the overtaking lanes on the highway. The road that connected the two main towns in the state of Tasmania was full of overtaking lanes, special lanes that allowed drivers to pass others going in the same direction at slower speeds. Even though the north-south highway was wide and newly surfaced, there was only one lane in each direction. The passing lanes brought relief to a driver trapped behind a truck with a heavy load or who was in a hurry like Rusli that morning. He had only been in the southernmost Australian state for four months but had travelled back and forth between Launceston and Hobart nearly 20 times in a car belonging to the University of Tasmania where he worked. For some reason, he had never before noticed the marker which was only a knee-high sign with three sides. The one facing north to Launceston said H100 while the one facing south to Hobart said L100. Rusli had been hired as a lecturer for one academic year of about eight months to teach at the Indonesian programme at the university. Because Indonesian was the one language offered on both campuses, at least once a week Rusli had to drive from Launceston where he was appointed.

Nitric oxide control of lower vertebrate blood vessels by vasomotor nerves

In mammals, much is understood about the endothelial and neural NO control mechanisms in the vasculature. In contrast, NO control of blood vessels in lower vertebrates is poorly understood, with the majority of research focusing on the presence of an endothelial NO system; however, its presence remains controversial. This study examined the mechanisms by which NO regulates the large blood vessels of non-mammalian vertebrates. In all species examined, the arteries and veins contained a plexus of NOS-positive perivascular nerves that included nerve bundles and fine, varicose nerve terminals. However, in the large arteries and veins of various species of fishes and amphibians, no anatomical evidence was found for endothelial NOS using both NADPH-diaphorase and eNOS immunohistochemistry. In contrast, perinuclear NOS staining was readily apparent in blue-tongue lizard, pigeon and rat, which suggested that eNOS first appeared in reptiles. Physiological analysis of NO signalling in the vascular smooth muscle of short-finned eel and cane toad could not find any evidence for endothelial NO signalling. In contrast, it appears that activation of the nitrergic vasomotor nerves is responsible for NO control of the blood vessels.

Modeling and simulation of collisions of heavy trucks with concrete barriers

On-site collision tests of full-scale concrete barriers are an important method to understand what happens to concrete barriers when vehicles collide with them. However, such tests require both time and money, so modeling and simulation of collisions by computer have been developed as an alternative in this research. First, spring subgrade models were developed to formulate the ground boundary of concrete barriers based on previous experiments. Then, the finite element method models were developed for both heavy trucks and concrete barriers to simulate their dynamic collision performances. Comparison of the results generated from computer simulations and on-site experiments demonstrates that the developed models can be applied to simulate the collision of heavy trucks with concrete barriers, to replicate the movement of the truck at the collision, and to investigate the performance of the concrete barriers. The developed research methodology can be widely used to support the design of new concrete barriers and the safety analysis of existing ones.

Design of electrical infrastructure at container terminal and 'net metering'

Net metering is generally a consumer-based incentive for renewable sources such as wind or solar power systems also referred to as dasiacogenerationdasia. It is still a grey area for container terminals with large electric machines, such as quay cranes, automatic stacking cranes, that can operate in the regenerative mode and export electric energy to the grid. With actual measured electrical data presented for discussion, this paper provides information for the readers to provide a better understanding of their access to net metering, ultilizing their electrical equipment capabilities and be informed for their next negotiation with the power supply company.

Exposure estimation, uncertainty and variability in occupational hygiene retrospective assessment

This thesis reports on a quantitative exposure assessment and on an analysis of the attributes of the data used in the estimations, in particular distinguishing between its uncertainty and variability. A retrospective assessment of exposure to benzene was carried out for a case control study of leukaemia in the Australian petroleum industry. The study used the mean of personal task-based measurements (Base Estimates) in a deterministic algorithm and applied factors to model back to places, times etc for which no exposure measurements were available. Mean daily exposures were estimated, on an individual subject basis, by summing the task-based exposures. These mean exposures were multiplied by the years spent on each job to provide exposure estimates in ppm-years. These were summed to provide a Cumulative Estimate for each subject. Validation was completed for the model and key inputs. Exposures were low, most jobs were below TWA of 5 ppm benzene. Exposures in terminals were generally higher than at refineries. Cumulative Estimates ranged from 0.005 to 50.9 ppm-years, with 84 percent less than 10 ppm-years. Exposure probability distributions were developed for tanker drivers using Monte Carlo simulation of the exposure estimation algorithm. The outcome was a lognormal distribution of exposure for each driver. These provide the basis for alternative risk assessment metrics e.g. the frequency of short but intense exposures which provided only a minimal contribution to the long-term average exposure but may increase risk of leukaemia. The effect of different inputs to the model were examined and their significance assessed using Monte Carlo simulation. The Base Estimates were the most important determinant of exposure in the model. The sources of variability in the measured data were examined, including the effect of having censored data and the between and within-worker variability. The sources of uncertainty in the exposure estimates were analysed and consequential improvements in exposure assessment identified. Monte Carlo sampling was also used to examine the uncertainties and variability associated with the tanker drivers' exposure assessment, to derive an estimate of the range and to put confidence intervals on the daily mean exposures. The identified uncertainty was less than the variability associated with the estimates. The traditional approach to exposure estimation typically derives only point estimates of mean exposure. The approach developed here allows a range of exposure estimates to be made and provides a more flexible and improved basis for risk assessment.

A heuristic algorithm for carton to pallet loading problem

This paper presents an algorithm used to solve a carton to pallet packing problem in a drink manufacturing firm. The aim was to determine the cartons loading sequence and the number pallets required, prior to dispatch by truck. The algorithm consists of a series of nine parts to solve this industrial application problem. The pallet loading solution relatively computationally efficient and reduces the number pallets required, compared to other 'trail and error' or manual spreadsheet calculation methods.

Passenger walking speed data for Australian domestic airports

The data covers the speed at which passengers walk through Australian domestic airport terminals, based on their group size.

Dorsal and ventral medullary catecholamine cell groups contribute differentially to systemic interleukin-1beta-induced hypothalamic pituitary adrenal axis responses

Medial parvocellular paraventricular corticotropin-releasing hormone (mPVN CRH) cells are critical in generating hypothalamic-pituitary-adrenal (HPA) axis responses to systemic interleukin-1beta (IL-1beta). However, although it is understood that catecholamine inputs are important in initiating mPVN CRH cell responses to IL-1beta, the contributions of distinct brainstem catecholamine cell groups are not known. We examined the role of nucleus tractus solitarius (NTS) and ventrolateral medulla (VLM) catecholamine cells in the activation of mPVN CRH, hypothalamic oxytocin (OT) and central amygdala cells in response to IL-1beta (1 microg/kg, i.a.). Immunolabelling for the expression of c-fos was used as a marker of neuronal activation in combination with appropriate cytoplasmic phenotypic markers. First we confirmed that PVN 6-hydroxydopamine lesions, which selectively depleted catecholaminergic terminals, significantly reduced IL-1beta-induced mPVN CRH cell activation. The contribution of VLM (A1/C1 cells) versus NTS (A2 cells) catecholamine cells to mPVN CRH cell responses was then examined by placing ibotenic acid lesions in either the VLM or NTS. The precise positioning of these lesions was guided by prior retrograde tracing studies in which we mapped the location of IL-1beta-activated VLM and NTS cells that project to the mPVN. Both VLM and NTS lesions reduced the mPVN CRH and OT cell responses to IL-1beta. Unlike VLM lesions, NTS lesions also suppressed the recruitment of central amygdala neurons. These studies provide novel evidence that both the NTS and VLM catecholamine cells have important, but differential, contributions to the generation of IL-1beta-induced HPA axis responses.

Medullary neurones regulate hypothalamic corticotropin-releasing factor cell responses to an emotional stressor

Hypothalamic–pituitary–adrenal axis activation is a hallmark of the stress response. In the case of physical stressors, there is considerable evidence that medullary catecholamine neurones are critical to the activation of the paraventricular nucleus corticotropin-releasing factor cells that constitute the apex of the hypothalamic–pituitary–adrenal axis. In contrast, it has been thought that hypothalamic–pituitary–adrenal axis responses to emotional stressors do not involve brainstem neurones. To investigate this issue we have mapped patterns of restraint-induced neuronal c-fos expression in intact animals and in animals prepared with either paraventricular nucleus-directed injections of a retrograde tracer, lesions of paraventricular nucleus catecholamine terminals, or lesions of the medulla corresponding to the A1 or A2 noradrenergic cell groups. Restraint-induced patterns of neuronal activation within the medulla of intact animals were very similar to those previously reported in response to physical stressors, including the fact that most stressor-responsive, paraventricular nucleus-projecting cells were certainly catecholaminergic and probably noradrenergic. Despite this, the destruction of paraventricular nucleus catecholamine terminals with 6-hydroxydopamine did not alter corticotropin-releasing factor cell responses to restraint. However, animals with ibotenic acid lesions encompassing either the A1 or A2 noradrenergic cell groups displayed significantly suppressed corticotropin-releasing factor cell responses to restraint. Notably, these medullary lesions also suppressed neuronal responses in the medial amygdala, an area that is now considered critical to hypothalamic–pituitary–adrenal axis responses to emotional stressors and that is also known to display a significant increase in noradrenaline turnover during restraint.

We conclude that medullary neurones influence corticotropin-releasing factor cell responses to emotional stressors via a multisynaptic pathway that may involve a noradrenergic input to the medial amygdala. These results overturn the idea that hypothalamic–pituitary–adrenal axis response to emotional stressors can occur independently of the brainstem.