Effects of adrenergic stimulants on the splenic diameter,haemoglobin content and haematocrit in anaesthetized dogs: determination of the adrenoceptor subtype responsible for changes in the splenic diameter

Changes in splenic diameter measured by sonomicrometry in response to various adrenergic stimulants were estimated together with simultaneously measured arterial haemoglobin content (HGB) and haematocrit (HCT) in anaesthetized dogs. Splenic diameter decreased following intravenous injections (i.v.) of adrenaline, noradrenaline and phenylephrine and splenic nerve stimulation associated with increases in arterial HGB and HCT, which were significantly attenuated by prazosin i.v. After prazosin i.v., adrenaline i.v. increased splenic diameter significantly, but noradrenaline i.v. did not. Isoprenaline i.v. increased splenic diameter transiently, followed by a decrease that was abolished by prazosin i.v. During occlusion of splenic arteries and veins, adrenaline i.v. and phenylephrine i.v. did not cause any change in arterial HGB and HCT. Injection to splenic artery (i.a.) of phenylephrine induced a significant decrease in splenic diameter that was attenuated by prazosin i.a. but not by yohimbine i.a. Clonidine i.a. did not change splenic diameter. The present results indicate that splenic contraction, which is mediated through α₁-adrenoceptor activation, causes a significant increase in arterial HGB and HCT.     

Issues to debate on the Women's Health Initiative: estrogen: an instrument or the conductor of the orchestra?

Although it is well known that cyclic production of sex hormones is essential to establish reproductive function and female characteristics, distant impacts of the activity of the female endocrine system result from a concert of delicate mechanisms. Estrogen is rather an instrument than a conductor in this physiological orchestra of the female. Thus, controversies in the explanation of results from studies on hormone replacement therapy (HRT) and cardiovascular disease (CVD) prevention might be eliminated, if we analyse not only the role of estrogen but a broader spectrum of factors leading to CVD. Authors would like to hypothesize that haemorheological changes in women around menopause, such as increased blood and plasma viscosity, haematocrit and fibrinogen, are largely responsible for the increased mortality in the post-menopausal life period. We believe that a cyclic withdrawal bleeding establishes a more favourable haemorheological condition, thus, sequentially administered estrogen might be protective in post-menopausal women. Nevertheless, other factors, that decrease blood viscosity, such as daily exercise, intake of ample amount of fluids as well as ideal nutrition, are equally important. We are confident that sequential HRT, as well as healthy life style and risk prevention programmes have their proper place in the management of this issue.     

Altitude exposure in sports: the Athlete Biological Passport standpoint

The Athlete Biological Passport (ABP) is principally founded on monitoring an athlete's biological variables over time, to identify abnormal biases on a longitudinal basis. Several factors are known to influence the results of these markers. However, the manner in which the altitude factor is taken into account still needs to be standardized. Causal relationships between haematological variables should be correctly integrated into ABP software. In particular, modifications of haematological parameters during and after exposure to different altitudes/hypoxic protocols need to be properly included within detection models. Copyright © 2013 John Wiley & Sons, Ltd.     

肺脏疾病患者血流变与临床生化指标观察

在肺脏疾病的发生及发展过程中，患者血液流变性可出现异常．本文对６２例肺脏疾病患者的血液流变及临床生物化学指标检测结果进行对比，表明血液流变指标的改变与生物化指标明显相关，现将结果报告如关．     

Multiple inert gas elimination technique for determining ventilation/perfusion distributions in rat during normoxia, hypoxia and hyperoxia

1. The use of the multiple inert gas elimination technique (MIGET) in quantifying ventilation/perfusion distributions (V*A/Q*) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert gas (method B). This method included acute simultaneous inert gas administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert gas levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V*A/Q* distributions reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V*A/Q* ratio of ventilation distribution and higher mean values of the V*A/Q* ratio of perfusion distribution with the usual method of inert gas administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion distributions found in group A during hypoxia.     

A method for rapid in vivo measurement of blood T1

We present a technique to measure the longitudinal relaxation time constant of venous blood (T_1b) in vivo in a few seconds. The MRI sequence consists of a thick‐slab adiabatic inversion, followed by a series of slice‐selective excitations and single‐shot echo planar imaging readouts. The time intervals between excitations were chosen so that blood in macroscopic vessels is fully refreshed between excitations, making the blood signal follow an unperturbed inversion recovery curve. Static tissue, which experiences the inversion and all excitation pulses, quickly reaches a steady state at a low signal as a result of partial saturation. This allows blood‐filled voxels to be discriminated from those containing static tissue, and to be fitted voxel‐by‐voxel to a simple inversion recovery model. The sequence was tested on a flow phantom with the proposed method, yielding T₁ values consistent to within 3% of those obtained using a conventional inversion recovery sequence with a spin‐echo readout. The method was applied to seven adult volunteers and 18 neonates. The blood T₁ of the neonates (1799 ± 206 ms; range, 1393–2035 ms) was found to be more variable than that of adults (1717 ± 39 ms; range, 1662–1779 ms). A linear correlation between the inverse of T_1b and the haematocrit was established in 12 neonates (R² = 0.90). Copyright © 2010 John Wiley & Sons, Ltd.     

Monensin potentiates lead chelation efficacy of MiADMSA in rat brain post chronic lead exposure

The present study evaluates combination therapy with a chelating agent, MiADMSA and a Na⁺ ionophore, monensin against sub-chronic lead toxicity in rats. Animals were exposed to 0.1% lead in drinking water for 16 weeks and then treated with either MiADMSA at 50 mg/kg body weight, or monensin at 10 mg/kg, or both in combination for a period of 5 days was administered. Biomarkers indicative of oxidative stress like ROS, GSH, GSSG and TBARS demonstrated lead-induced toxic manifestations in blood, kidney and brain. Antioxidants like SOD, catalase and glutathione peroxidase along with specific lead biomarker, blood ALAD were also severely depleted in lead intoxicated animals. Serum parameters and histopathological findings supported the said results. MiADMSA treatment during both mono- and combination therapy with monensin, restored the antioxidant status and recovered biochemical and haematological variables due to lead. However, monensin alone was not found to be effective in the given scenario. Interestingly, combination therapy in its ability to revert lead-induced overall systemic toxicity was only found at par with the MiADMSA monotherapy except for its chelation potential. Monensin given in combination with MiADMSA potentiated its lead chelation ability especially from brain, along with maintaining the normal copper concentrations in the organ unlike MiADMSA monotherapy.     

Haematocrit and risk of development of Type 2 diabetes mellitus in middle-aged Japanese men.

AIMS: To investigate the association between haematocrit and risk of development of diabetes. Methods The study enrolled 2953 normoglycaemic [fasting plasma glucose (FPG) < 6.1 mmol/l and taking no hypoglycaemic medication] Japanese men aged 35-59 years and free of medication for hypertension and history of cardiovascular disease. FPG was measured at periodic annual health examinations from May 1994 through May 2001. Men in whom Type 2 diabetes mellitus (FPG > or = 7.0 mmol/l or receiving hypoglycaemic medication) was found during repeated surveys were classified as having Type 2 diabetes. RESULTS: The estimated incidence rates for Type 2 diabetes during 7 years of follow-up were 3.1% [[95% confidence interval (CI) 1.6, 4.6]], 4.6% (2.8, 6.4), 5.0% (3.2, 6.9), 6.4% (4.4, 8.5), and 11.5% (8.9, 14.2) for respective haematocrit levels of < 42.6, 42.6-44.0, 44.1-45.3, 45.4-46.8, and >/= 46.9% (the log-rank test: P < 0.001). After controlling for potential predictors of diabetes, the respective relative risks for Type 2 diabetes were 1.0 (reference), 1.52 (95% CI 0.81, 2.86), 1.24 (0.66, 2.31), 1.57 (0.86, 2.88), and 2.30 (1.30, 4.08) (P for trend = 0.002). From stratified analyses by presence or absence of a risk factor, a linear association of haematocrit level with risk of development of Type 2 diabetes was also observed. CONCLUSION: These results indicate that haematocrit contributes to the risk of developing Type 2 diabetes.