Determination of Total Biotin by Liquid Chromatography Coupled with Immunoaffinity Column Cleanup Extraction: Multilaboratory Testing, Final Action 2016.02.

Single- and multilaboratory testing data have provided systematic scientific evidence that a simple, selective, accurate, and precise method can be used as a potential candidate reference method for dispute resolution in determining total biotin in all forms of infant, adult, and/or pediatric formula. Using LC coupled with immunoaffinity column cleanup extraction, the method fully meets the intended purpose and applicability statement in AOAC Standard Method Performance Requirement 2014.005. The method was applied to a cross-section of infant formula and adult nutritional matrixes, and acceptable precision and accuracy were established. The analytical platform is inexpensive, and the method can be used in almost any laboratory worldwide with basic facilities. The immunoaffinity column cleanup extraction is the key step to successful analysis.

[Proper usage of procalcitonin]. / Du bon usage de la procalcitonine.

In the last fifteen years, procalcitonin measurement has been evaluated as a rapid diagnostic aid for suspected infection. Procalcitonin is now widely used in any febrile patient despite the lack of evidence supporting that practice. Indeed, procalcitonine has proven effective in the intensive care setting, as a diagnostic aid for septic shock, as a prognostic instrument and to tailor the duration of antibiotic treatment. Studies in non intensive care settings are more recent and scarce. Procalcitonin has been assessed in the emergency department in patients with lower respiratory tract infections and in patients admitted for an acute febrile illness. Results are encouraging but preliminary, therefore procalcitonine measurement should be restricted to patients with criteria of severe infection for the time being.

Women's health programs at the Centers for Disease Control and Prevention.

The Centers for Disease Control and Prevention (CDC) offers a variety of resources for health care professionals and agencies, policy makers, consumers, academicians, and others. As the nation's prevention agency, the CDC supports epidemiologic and behavioral research, national and state-based surveillance activities, disease prevention programs, scientific and public health infrastructure development, and much more. Selected resources that may be helpful to those who work to improve the health and safety of women are described.

Prevention works for women: women's health at the CDC.

Actively protecting America's health and safety, the Centers for Disease Control and Prevention (CDC) focuses on four priorities: 1) strengthening science for public health action, 2) collaborating with health care partners for prevention, 3) promoting healthy living at every stage of life, and 4) promoting health globally. The CDC plays a critical role in promoting the health and safety of women across the lifespan, through programs on human immunodeficiency virus infection, injury, contraceptive safety and efficacy, adolescent health, smoking, breast and cervical cancer, cardiovascular disease, and reproductive health.

Do physicians modify their prehospital management of patients in response to a public campaign on chest pain?

The goals of this study were to analyze the impact of a public campaign on chest pain on physicians involved in the prehospital care of patients with this symptom, in terms of physician delay, rates of immediate hospitalization, and of transportation by ambulance. Prehospital delays and decisions for all 866 patients with chest pain managed by the community and generalist physicians or by emergency physicians, who presented to the emergency department of a teaching hospital during the 12 months of the campaign, were compared with those of all 749 patients with similar presentations during the 12 months before it. When community and generalist physicians were involved, median (110 minutes) physician delay did not decrease during the campaign, whereas it decreased from 65 to 56 minutes (p <0.003) when emergency physicians were involved. Rates of immediate hospitalization (73%) and of transportation by ambulance (47%) of patients managed by community and generalist physicians were unaffected by the campaign, whereas they increased from 96% and 89%, respectively, to 98% (p = 0.09) and 94% (p <0.02) when emergency physicians were involved. Similar observations were made in patients with confirmed acute myocardial infarction and unstable angina and remained highly significant after adjustment for differences in clinical characteristics. Thus, community and generalist physicians did not significantly modify their prehospital management of patients with chest pain despite a public campaign. To be successful, guidelines on the matter have to be developed with the active participation of these physicians.

1995 assisted reproductive technology success rates: national summary and fertility clinic report.

Although ART offers important options for the treatment of infertility, the decision to use ART involves many factors in addition to success rates. Going through repeated ART cycles requires substantial commitments of time, effort, money, and emotional energy. Couples and individuals considering ART should carefully examine all related financial, psychologic, ethical, and medical issues before beginning treatment. They should also contact ART clinics to discuss their specific medical situation and potential for success using ART. The next published report will feature 1996 data and provide a listing of clinics that did not submit data. Eventually, the annual report will include information from all U.S. fertility clinics, not just those that are SART members.

Skeletal muscle metabolism in uremic rats: a 31P-magnetic resonance study.

The effect of uremia on skeletal muscle metabolism of the rat was examined using 31P-magnetic resonance spectroscopy. Three weeks following either a 5/6 nephrectomy or a sham operation, Wistar rats were placed in a 7T magnet, and the sciatic nerve was stimulated for 10 min. Analysis of spectra allowed calculation of intracellular pH and the relative concentrations of phosphocreatine (PCr), inorganic phosphate (Pi) and ATP. [ADP] was calculated from the creatine kinase equilibrium. There was a significant reduction in the resting intracellular [Pi] despite an elevation in extracellular [Pi], probably due to a reduction in the activity of the membrane Na/Pi cotransporter on account of a reduced sodium gradient. Despite anemia and uremia, there were no significant metabolic abnormalities during exercise and recovery accompanying this substantial reduction in glomerular filtration rate implying that at this level of renal impairment, there is no mitochondrial dysfunction.

The effect of iron deficiency on skeletal muscle metabolism of the rat.

Using 31P magnetic resonance spectroscopy we compared skeletal muscle bioenergetics in Wistar rats made chronically anaemic by being fed a diet deficient in iron for 6 weeks with chronically iron deficient animals given a normal diet as well as 5 mg iron dextran at 2 or 7 days before experimentation. Spectra of the gastrocnemius muscle were taken at rest and during stimulation of the sciatic nerve at 2 Hz for 10 min. Relative concentrations of intracellular phosphate (Pi), phosphocreatine (PCr) and ATP were determined. Iron deficiency increased PCr breakdown and production of acid in stimulated skeletal muscle. Recovery of PCr and Pi concentrations after exercise was slow. These metabolic changes are consistent with either a reduction in supply of oxygen to the muscle cell or altered oxidative phosphorylation by the mitochondria. The latter may be mediated by defective function of iron-containing proteins crucial in oxidative phosphorylation and this is suggested both by the observation that treatment with iron, sufficient to correct the anaemia, does not completely reverse the metabolic changes and that there is a different time course for such metabolic improvements and the observed increase in haemoglobin concentration.

Na+/H+ and HCO3-/Cl- exchange in the control of intracellular pH in vivo in the spontaneously hypertensive rat.

1. We have previously shown that the cytosolic acid concentration changes in skeletal muscle during contraction in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats in vivo. We have now found that this change was unaffected by 20% inhaled CO2 or by 4,4'-di-isothiocyanostilbene-2,2'-disulphonate. This is evidence that HCO3- exchange in vivo is not important in the control of cytosolic acid concentration during skeletal muscle contraction in either spontaneously hypertensive or Wistar-Kyoto rats. 2. We have also previously shown that the difference in cytosolic acid response during contraction between spontaneously hypertensive and Wistar-Kyoto rats is due to increased Na+/H+ antiporter activity in the spontaneously hypertensive rats. Our current findings suggest that this increase in Na+/H+ antiporter activity is more likely to be due to a change in the Km of the antiporter than to a change in the Vmax. We estimate that the Km of the antiporter changes in hypertension from pH 7.16 to 7.33. 3. We did not find any differences between adult spontaneously hypertensive and Wistar-Kyoto rats with regard to resting intracellular and extracellular pH and resting intracellular and extracellular HCO3- concentrations. In addition, we did not find any evidence of a difference in skeletal muscle HCO3-/Cl- exchange between adult spontaneously hypertensive and Wistar-Kyoto rats. 4. At rest, skeletal muscles of the spontaneously hypertensive and Wistar-Kyoto rats have the same lactate production, HCO3-/Cl- exchange and arterial partial pressure of CO2. In addition, we can also calculate that at a resting intracellular pH of 7.05 in the spontaneously hypertensive rats, the antiporter is 66% saturated.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of beta 2-adrenoceptor stimulation and blockade of L-type calcium channels on in vivo Na+/H+ antiporter activity in rat skeletal muscle.

We have studied the in vivo response of the Na+/H+ antiporter in skeletal muscle to beta 2-adrenoceptor stimulation with isoprenaline and the effect of blocking L-type calcium channels with nifedipine. Na+/H+ antiporter activity in skeletal muscle in vivo increased after beta 2-adrenoceptor stimulation with isoprenaline; nifedipine attenuated that effect. This suggests that opening of L-type calcium channels is necessary for full activation of the Na+/H+ antiporter in skeletal muscle. Bleeding also increased Na/H+ antiporter activity, which we believe could be explained by an increase in sympathetic nervous system activity as a result of hypotension. This may be one of the mechanisms by which animals under stress prepare their skeletal muscle for exercise as part of the 'fright and flight' reaction.

Evidence for increased in vivo Na(+)-H+ antiporter activity and an altered skeletal muscle contractile response in the spontaneously hypertensive rat.

We have assessed the in vivo activity of the Na(+)-H+ antiporter skeletal muscle in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) controls using phosphorus (31P) nuclear magnetic resonance spectroscopy to measure changes in cytosolic acid concentrations during isometric contraction. During contraction there was a small rate of rise in skeletal muscle cytosolic acid concentration to a smaller maximum concentration in SHR. This difference in acid response was removed by amiloride and was not attributable to differences in cell buffering or the rate of production of lactic acid, suggesting that the difference in acid response in SHR skeletal muscle is due to increased in vivo Na(+)-H+ antiporter activity. Amiloride reduced resting muscle glycogen concentration and increased muscle lactate concentration in the SHR. This could be related to altered in vivo calcium metabolism. The maximum tension produced by skeletal muscle during contraction in SHR was less than in WKY rats, and relaxation between twitches was significantly greater, consistent with the finding of increased vascular smooth muscle relaxation in essential hypertension. Since increased Na(+)-H+ antiporter activity occurs in association with increased relaxation of both skeletal and vascular smooth muscle, these data are not consistent with a relationship between increased Na(+)-H+ antiporter activity and increased maximal muscle tension development. However, they show that increase Na(+)-H+ antiporter activity is associated with increased muscle relaxation.