Blood sampling techniques for studying rapidly turning over metabolic fuels in mice

Experiments were carried out in control and Ehrlich ascites carcinomatous mice to determine whether orbital venous sinus blood could be used to reflect blood in the systemic circulation (decapitation blood) in the case of a rapidly turning over metabolic fuel such as free fatty acids. The early time course of intravenously injected, labeled free fatty acids was measured using (9, 10-(3)H) palmitic acid and (1-(14)C) linoleate complexed to mouse serum. No significant differences between decapitation and orbital sinus blood were found at early times in either group of mice. The orbital sinus clearly contains blood that is not stagnant and is replaced so rapidly that it is suitable for studying very rapidly turning over, circulating metabolites.     

Constant external work cycle exercise--the performance and metabolic effects of all-out and even-paced strategies

The immunosuppressive metabolite of leflunomide, A77 1726, inhibits the enzymatic activity of protein tyrosine kinases and of dihydro-orotic acid dehydrogenase, an enzyme involved in pyrimidine biosynthesis. Here murine CTLL cell lines were studied to determine which of the biochemical targets of A77 1726 was responsible for the observed inhibition of proliferation and cytotoxic activity. At low concentrations of A77 1726, pyrimidine biosynthesis is the target, since inhibition of proliferation correlates with a reduction in pyrimidine NTP levels and is reversed by uridine. At higher concentrations of A77 1726, uridine no longer reverses the inhibition of proliferation even though pyrimidine NTP levels are restored. This second mechanism for inhibiting proliferation is probably inhibition of protein tyrosine kinases, since these higher concentrations of A77 1726 inhibit IL-2-induced tyrosine phosphorylation of Jak1 and Jak3, the protein tyrosine kinases initiating signaling by the IL-2R. Tyrosine phosphorylation of the beta-chain of the IL-2R, which is required for IL-2-driven proliferation, is also inhibited by A77 1726. Cytotoxicity of a CTLL line that overexpresses the Lck protein tyrosine kinase is inhibited by A77 1726; this inhibition is not affected by uridine, but does correlate with inhibition of an Lck in vitro kinase reaction. These studies establish that inhibition of pyrimidine biosynthesis and that of protein tyrosine kinase both contribute to the effects of A77 1726 on CTLL cell lines.     

Dietary L-arginine in renal disease

The amino acid L-arginine is a substrate for at least three products involved extensively in tissue injury and fibrosis. L-arginine is metabolized to L-proline, a major constituent of the collagen that makes up fibrotic extracellular matrix. L-arginine is a precursor for polyamines, which are required for proliferative responses characteristic of many renal disease. L-arginine is also the sole substrate for generation of nitric oxide (NO) which, produced in large quantities by macrophages, has been implicated in tissue injury. On the other hand, NO produced in small quantities by endothelium is a critical vasodilator. Given the importance of elevated intraglomerular pressure in renal injury, it is perhaps not surprising that dietary L-arginine supplementation increase NO generation and is beneficial in reducing intraglomerular pressure and subsequent disease. Other data, based on the therapeutic effects of low protein diets, have suggested that L-arginine restriction limits NO-mediated glomerular injury and greatly reduces matrix accumulation, consistent with the idea that limitation of substrate effectively diminishes injurious NO levels, polyamine synthesis, and collagen production.     

Uterine work in parturition

This paper presents a theoretical analysis relating work expended by the uterus to the synergistic relationship between intrauterine pressure (IUP) and cervical dilatation (CD). By utilizing a geometrical model for the fetal presenting part which is assumed to be in contact with the cervix, the changes in internal volume of the uterus with each contraction can be shown to be functionally related to cervical dilatation. Thus work, expressed in terms of foot-pounds, can be calculated using the integral of pressure times incremental volume. By simulating intrauterine pressure and cervical dilatation with continuous analytical wave forms, the alterations required in uterine work to dilate the cervix are calculated for various wave-form aberrations which are seen in clinical situations. The wave-form aberrations are applied to an elastic cervical model as well as a viscoelastic model. Using the principles of thermodynamics the areas of the fetouterine complex which absorb the work generated by the contractions are defined. It is shown that the efficiency of the contractions to dilate the cervix can be calculated by evaluating the work expended in these various areas of energy absorption. The purpose of this paper is to present the theory upon which clinical findings in obstetrics can be based so that conclusions drawn will be technically sound.     

New techniques in neurosurgery

Society demands for exactness and low complication rates of surgical treatment are high. Surgical training in the apprentice manner has been significantly reduced in Denmark since 1981 and e.g. the ability to visualize in three dimensions among younger neurosurgeons has diminished. Computer technology now makes it possible to create 3-D images that with incorporation of functionality leads to a faster and better understanding of neuroanatomy. In addition--for the sake of precision--true robotic instrumentation and navigational instruments have been introduced. The technological investments are compensated by reduced costs due to operative complications. A prerequisite for these developments are a close collaboration between medical doctors and engineers, keeping the respect for humanity intact. A survey of developmental areas in the neurosurgical techniques of today is given.     

Dietary behavior during obesity

Human alimentary behavior deals with a threefold need: energetic, hedonic and sociocultural. Among the clinical constellation offered by obese patients it could be worthwile to distinguish: 1. Some constitutional and organic obesities, pathogenesis of which does not imply an abnormality of alimentary behavior; 2. Conversely, in some other cases, psychological induced behavioral abnormalities are able to lead to an overstepping of the so called "normal" weight; 3. In other instances, the alimentary behavior reflects the elevation of the set point for weight. All these mechanisms are mutally reinforcing and could act simultaneously or successively accounting for the great variability of the individual situations. In any case environmental conditions are operating and play a pathogenic role more especially as the anatomic, physiologic and psychologic background is predisposed.     

Musculoskeletal disorders in visual display unit work: gender and work demands

In addition to physiologic differences between men and women, differences in pain reporting and medical care-seeking behavior, job assignments and ergonomic exposures (including work in the home), and strategies for performing various physical tasks must be considered.     

Dietary control of exertional rhabdomyolysis in horses

OBJECTIVE: To determine whether feeding a low-carbohydrate, high-fat diet would decrease severity of exercise-induced muscle injury in horses with exertional rhabdomyolysis. ANIMALS: 19 horses with a history of exertional rhabdomyolysis. DESIGN: Case series. PROCEDURE: Specimens of the semitendinosus or semimembranosus muscle were obtained for histologic examination, and serum creatine kinase (CK) and aspartate transaminase (AST) activities 4 hours after exercise were determined. Horses were then fed a low-carbohydrate, high-fat diet, and serum CK and AST activities 4 hours after exercise were reevaluated at approximately monthly intervals for 3 to 6 months. RESULTS: Serum CK and AST activities 4 hours after exercise were high before any change in diet. All 19 horses had evidence of chronic myopathic change and abnormal glycogen accumulation in muscle biopsy specimens; 11 horses also had evidence of complex polysaccharide accumulation. Adaptation to diet change required approximately 3 to 6 months. Sixteen horses did not have any episodes of exertional rhabdomyolysis after 3 to 6 months of diet change, and 3 horses had mild episodes of exertional rhabdomyolysis following either a reduction in dietary fat intake or restriction in exercise. Postexercise serum CK and AST activities 3 to 6 months after the change in diet were significantly less than initial values. CLINICAL IMPLICATIONS: Results indicated that exertional rhabdomyolysis may be a result of abnormal carbohydrate metabolism in some horses. Feeding a diet with low carbohydrate and high fat content may reduce severity of exercise-induced injury in some horses with exertional rhabdomyolysis.     

A vacation from work: Changes in work and nonwork outcomes.

Compared pre- and postvacation measures in 6 areas: job satisfaction, job involvement (measured as central life interest [JIC] and as importance of performance to self-esteem), organizational commitment, turnover intention, and life satisfaction. Responses obtained from 92 female and 36 male employees (mean age 39 yrs) in technical, administrative, clerical, and service positions 1 wk prior to and 1 wk following their vacations indicate that the vacation had a significant overall effect on the variables studied, even with sex, education, income, and occupational prestige included as covariates. Specifically, JIC decreased and both life satisfaction and turnover intention increased. Hierarchical regression analyses indicated that vacation satisfaction and an interaction term involving the prevacation measure and vacation satisfaction increased the predictability of the postvacation measure by 7% in 2 cases: life satisfaction and job satisfaction. Length of vacation did not contribute significantly to the prediction of any of the postvacation variables. The decrease in JIC is discussed in terms of the relative salience of work and nonwork domains and the allocation of psychological resources. Overall, the results are viewed as supporting an open-systems model of organizational behavior. (75 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dietary management of acute diarrhoea in childhood

Gastroenteritis in children is usually treated with the graded introduction of milk feeds after rehydration. Although having never been rigorously tested, the practice of gradually increasing milk strength over several days has been considered an appropriate means of warding against lactose intolerance and preventing sensitization to cow's milk antigens. These guidelines were formulated in Europe and North America and invariably lead to a reduction in nutrient intake. Malnourished children in developing countries, however, may experience an average 5-6 episodes of acute diarrhea per year and the nutrient effects are cumulative. A recent study from Latin America explored whether continued feeding is safe for infants under age 6 months and whether malnourished children respond adversely. Infants randomly assigned to receive full strength cow's milk immediately after rehydration did not have more treatment failures, higher stool outputs, or longer lasting diarrhea than those whose feeds were regarded to full strength over 48 hours. It is unclear, however, whether the youngest or more malnourished subjects were overrepresented in the treatment failures. Results also indicate that deciding to change treatment should not be dictated by the presence of reducing substances in the faeces; the majority of infants with reducing substances in their stools did well. This study offers the first scientific support for rapidly reintroducing full-strength milk formula after gastroenteritis is malnourished patients under 6 months of age. The 10% of infants in which dehydration recurs after reintroducing milk feeds are still difficult to manage. In the absence of yogurt or lactose-free formula, a locally-produced modular feed of chicken, starch, and vegetable oil may be suitable.     

A study of the performance and comparability of the sampling response to cotton dust of work area and personal sampling techniques

In order to compare and contrast the sampling response to cotton dust of two forms of dust sampling 85 work areas were identified over a 2-year period for investigation in eight Lancashire spinning mills. Three hundred and five work area dust samples were undertaken and 252 personal dust samples were performed. Operatives who spent a minimum of 80% of their working shift in the area in which work area sampling was also performed were selected for personal sampling. Work area dust exposures have recently shown an upward trend, with highest concentrations occurring in the ring spinning room (median 1.15 mg m-3, range 0.82-2.06). Personal dust samples showed a reduction in dust exposures as cotton processing progressed, from a high in the opening room (median value of 6.24 mg m-3, range 1.0-41.5) to a minimum of 1.02 mg m-3 (range 0.30-0.93) in the winding room. The ratio of measured personal sampling dust exposure to work area sampling exposure was used to compare the relative performance of the two techniques. This ratio was highest in the early processes. There was a 7.8-fold difference in measurement between the two techniques in the opening processes, falling to 4.9 in carding and 4.2 in the other card-room processes. However in ring spinning the ratio was only 1.4, suggesting a degree of comparability in the methods at this stage of processing. The value rose to 2.5 for the last stage (winding). Respiratory disease is known to occur predominantly in the early stages of processing (opening and carding) where high dust concentrations are found using the personal technique. These data support the use of personal sampling for setting exposure limits to cotton dust in preference to the current recommended method using work area sampling techniques, which may significantly underestimate dust exposure in the high risk work areas and is outdated.