Role of glucoregulatory hormones in potassium homeostasis

An incompletely defined interregulatory balance exists between potassium, insulin, and aldosterone. That potassium administration enhances and hypokalemia depresses aldoterone production is well known. It is not as well known that the same relationship exists between potassium and insulin. In a normal subject, acute hyperkalemia stimulates release of insulin from the pancreas. Potassium deficiency, on the other hand, may depress production of insulin. Both insulin and aldosterone, under appropriate conditions, may indirectly promote transfer of potassium ions from extracellular to intracellular fluid. In contrast, deficiency of either insulin or aldosterone, and expecially both, may favor development of hyperkalemia.Pharmacologically, glucagon, epinephrine, norepinephrine, and somatotropin may also influence transfer of potassium between extracellular and intracellular fluid. Their precise physiological roles in potassium homeostasis, however, are much less evident than that for insulin and aldosterone.It is the intention of this brief review to point out the salient effects and mechanisms whereby the foregoing substances affect potassium homeostasis and to point out physiologically important interrelationships wherever possible

Catastrophic medical events with exhaustive exercise: “White collar rhabdomyolysis”

Each year, especially in the United States, young and middle aged men die from a variety of causes during or following intense physical exertion. For unknown reasons, death and disability as a consequence of physical effort are virtually unknown in women, despite the fact that they participate heavily in competitive sports.The most important complications of exhaustive exercise are shown in Table 1. Of these, rhabdomyolysis, especially if associated with exertional heat stroke, is one of the most devastating clinical illnesses that exists. The term rhabdomyolysis defines an injury to skeletal muscle cells of such severity that their contents leak into the circulation. The injury may be confirmed biochemically by demonstrating elevated concentrations of enzymes in serum that are specifically located in skeletal muscle cells (CK-MM, aldolase) or myoglobin. Myoglobin released into the circulation is filtered and excreted into the urine, so-called myoglobinuria. The latter invokes the risk of acute renal failure (pigment nephropathy). Exertional rhabdomyolysis is an exceptionally common event. It is probably experienced in mild form by everyone who has undergone some form of exercise training during their youth when it is expressed simply by stiff and tender muscles. If at that time someone happened to measure a serum CK value, it would be slightly to modestly elevated. Some of the most classic examples of frank exertional rhabdomyolysis occur among our most highly trained endurance runners. In the majority of cases, there is no history or other apparent evidence for myopathy before the event. In most who survive major episodes, subsequent muscle testing has shown no results that suggest a hereditary myopathy such as McArdle's Syndrome, carnitine palmityl transferase deficiency, or other myopathy. Because of this, it is assumed that any normal person may develop frank rhabdomyolysis provided the provocation is adequate. Provocative events consist of exhaustive exercise, especially when competitive, and particularly if the athlete musters his supreme effort to win during the last segment of a race. Hot or warm weather and a high relative humidity increase the risk enormously. Victims of this disorder often give a history that they continued to run despite cramping pain and “dead legs”. Some of them continue to run despite obvious disorientation and confusion. Observers commonly recall that victims appeared pallid or gray as if their skin vessels had become constricted as a result of a massive discharge of norepinephrine or alternatively, their cardiac output and peripheral circulation had failed. It seems that it is this last burst of effort that often provides the coup de grace, so that the patient develops major and widespread soft tissue injury and in some cases, heat stroke as an associated illness.It is unfortunate that the gravity of acute exertional rhabdomyolysis is so often unappreciated by physicians who initially provide care for these patients. Although the victim may collapse and appear to recover quickly, in some of these, potentially fatal metabolic acidosis, hyperkalemia, disseminated intravascular coagulation and the acute respiratory distress syndrome may appear during the following 24 hours. The syndrome of rhabdomyolysis is given little attention in the major textbooks of internal medicine. Perhaps this is one of the reasons why the gravity of the illness is so commonly unappreciated at the onset when appropriate identification and treatment of its complications could be life saving.There is strong evidence that training induces a degree of resistance to development of exertional rhabdomyolysis as well as exertional heat stroke. Some of this evidence will be reviewed, but with emphasis on the fact that even a highly trained athlete can still develop exertional rhabdomyolysis. Following the review of the physiological mechanisms that help forestall injury incident to exertion, several cases will be presented that will highlight some of the devastating complications of exercise

Miniaturized Microstrip Filter Design Using Active Learning Method

Relating coupling and external quality factor of a filter to the physical parameters of the structure which is the final step of any filter design is usually complicated due to geometrical complexities of the filter, or in the case of microstrip resonators due to the lack of the exact solution for the field distribution. Therefore, common approach is using time consuming full wave simulations. In this paper active learning method (ALM) which is a fuzzy-based modeling technique developed by a procedure algorithmically mimics the information-handling process of the human brain, is proposed to overcome this drawback. Modeling steps of an unknown function using ALM will be described using an illustrative example. Afterwards, the modeling approach will be implemented to model coupling factor between two coupled spiral resonators (SRs) for two different coupling structures and external quality factor of the same resonator. Accuracy of the extracted surfaces is validated using two different criteria. Using the extracted surfaces; a four pole chebychev bandpass filter was designed and fabricated. Good agreement between the measured response and simulation validated the accuracy of the extracted surfaces again. Comparing the fabricated SR filter with a square open loop resonator (SOLR) one demonstrates more than 70% of filter area reduction

Iron‐Mediated Electrophilic Amination of Organozinc Halides using Organic Azides

A wide range of alkyl‐, aryl‐ and heteroarylzinc halides were aminated with highly functionalized alkyl, aryl, and heterocyclic azides. The reaction proceeds smoothly at 50 °C within 1 h in the presence of FeCl3 (0.5 equiv) to furnish the corresponding secondary amines in good yields. This method was extended to peptidic azides and provided the arylated substrates with full retention of configuration. To demonstrate the utility of this reaction, we prepared two amine derivatives of pharmaceutical relevance using this iron‐mediated electrophilic amination as the key step

Ready to Serve? The Aging Network and LGB and T Older Adults

This study provides the first snapshot of the Aging Network's experience with and readiness to serve lesbian, gay and bisexual older adults and transgender older adults (LGB and T) across all regions of the United States. The directors of every Area Agency on Aging (AAA) and directors of State Units on Aging (SUAs) in single planning and service area states (where the state, in essence, serves as the AAA) were invited to participate in an online survey in May 2010. Fifty percent (320) of eligible agencies completed the study. Participants represented 45 states and all regions of the country. More than half of the participants served an area that was primarily rural and nearly all participants (87%) provided some direct aging services

2-Cyanoethylzinc iodide: A new reagent with reactivity umpolung

2-Cyanoethylzinc iodide 1 generated in over 90% yield from 3-iodopropionitrile and zinc in THF can be transmetallated to the copper and titanium derivatives 3 and 4 which react in good yields, respectively, with acyl chlorides, enones, allylic halides and benzaldehyde.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27612/1/0000656.pd

Over a millon Creatine Kinase due to a heavy work-out: A case report

Rhabdomyolysis induced by exercise is a very well known entity, several cases has been reported in the literature related with strenuous activities, weight lifting, marathon running, overexertion in an untrained person, knee bends, etc. We reported an interesting case of exercise-induced rhabdomyolysis in a 25 year old Hispanic male, after resuming his regular physical activity, with the highest creatine kinase described in the literature, successfully treated with aggressive hydration only and no complications

A Mild Oxidation of 1.1 - Diorganometallics to Ketones and Aldehydes. A New Stereoselective Aunroach to Aldol products - Part 1

The 1,1-diorganometallics of magnesium and zinc 1 are converted by the reaction with Me3SnCl to the 1,1-diorganometallics of tin and zinc 2 which are readily oxidized by dry air at -10[deg] to 0[deg]C to afford the corresponding aldehydes and ketones 3 in 57-91% yield. This mild oxidation reaction allows a new stereoselective approach to aldol products. An extension of the reaction to 1,1-diorganometallics of silicon and zinc is described.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27621/1/0000665.pd

The reaction of the highly functionalized copper reagents RCu(CN)ZnI.BF3 with aldehydes

The new copper reagent RCu(CN)ZnI 2, which may contain important functional groups like the ester, nitrile, enoate or imide group, react in the presence of BF3.OEt2 with aldehydes to afford polyfunctional secondary alcohols in good yields (68-93%).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27616/1/0000660.pd

Spin Discrimination in Three-Body Decays

The identification of the correct model for physics beyond the Standard Model requires the determination of the spin of new particles. We investigate to which extent the spin of a new particle $X$ can be identified in scenarios where it decays dominantly in three-body decays $X\to f\bar{f} Y$. Here we assume that $Y$ is a candidate for dark matter and escapes direct detection at a high energy collider such as the LHC. We show that in the case that all intermediate particles are heavy, one can get information on the spins of $X$ and $Y$ at the LHC by exploiting the invariant mass distribution of the two standard model fermions. We develop a model-independent strategy to determine the spins without prior knowledge of the unknown couplings and test it in a series of Monte Carlo studies.Comment: 31+1 pages, 4 figures, 8 tables, JHEP.cls include