活动性肺结核患者血清Fad D9重组蛋白、sCD14-ST及单核细胞P糖蛋白水平及其临床意义

目的探讨活动性肺结核(APTB)患者血清Fad D9重组蛋白、可溶性白细胞分化抗原14亚型(sCD14-ST)、单核细胞P糖蛋白(Pgp)表达及其临床意义。 方法选取96例APTB患者(APTB组),按照肺部病灶有无空洞和病灶肺叶数分亚组。同期选择体检健康且经γ干扰素释放试验检测阴性者(健康对照组,HC组)及阳性者(结核潜伏感染组,LTBI组)各48例。比较各组血清Fad D9重组蛋白、sCD14-ST、Pgp水平。评估Fad D9重组蛋白、sCD14-ST、Pgp诊断APTB和鉴别APTB、LTBI的价值。 结果Fad D9重组蛋白、sCD14-ST、Pgp水平APTB组＞LTBI组＞HC组,且有空洞者高于无空洞者,病灶肺叶≥3个者高于＜3个者(P＜0.05)。Fad D9重组蛋白、sCD14-ST、Pgp对APTB诊断和APTB、LTBI鉴别有良好效能(P＜0.05)。 结论APTB患者血清Fad D9重组蛋白、sCD14-ST及Pgp明显升高,且与肺部病灶的严重程度有关。     

The sodium channels of the neuroblastoma x glioma 108 CC 15 hybrid cell change their sensitivity for volatile and local anesthetics upon continuous passage

Summary We have studied the ion flux through the sodium channels of low passage number (<50p.) and high passage number (>150p.) neuroblastoma x glioma hybrid cells using [¹⁴C] guanidinium and specific neurotoxins to induce channel opening and closing. The sodium channels of low passage number hybrid cells could be opened by veratridine alone, suggesting the presence of voltage dependent channels in agreement with electrophysiological studies reported in the literature. The sodium channels of the high passage number hybrid cells, however, needed the synergistic action of veratridine and scorpion toxin for activation suggesting that these channels are silent. The [¹⁴C] guanidinium ion flux through the sodium channels of the high passage number hybrid cells was inhibited by significantly lower concentrations of the volatile anesthetics (halothane, isoflurane and enflurane) and the lcoal anesthetics (tetracaine and bupivacaine) than the comparable flux through the sodium channels of the low passage number hybrid cells.Dedicated to Prof. Dr. E. Wecker on the occasion of his 65th birthday.     

Compartmentation of cardiac adenine nucleotides and formation of adenosine

Summary After prelabeling the adenine nucleotides (ATP, ADP, AMP) of isolated perfused guinea pig hearts with either¹⁴C-adenine or¹⁴C-adenosine for 35 min, labeled adenosine, inosine, hypoxanthine and cyclic 35-AMP (cAMP) were continuously released into the cardiac perfusate. Determination of the specific activities (SA) of the adenine nucleotides, cAMP, and their breakdown products (adenosine, inosine, hypoxanthine) in tissue and perfusate revealed: Under steady state conditions the SA of adenosine and cAMP in the perfusate were of the same order of magnitude and proved to be many times higher than the SA of the respective precursor adenine nucleotides. This difference was observed regardless whether adenine or adenosine was used as prelabeling substance. The SA of inosine and hypoxanthine in the perfusate were constantly lower than the SA of adenosine. Cardiac ischemia of 6 min, which resulted in a markedly increased formation of adenosine, led to a pronounced decrease in the SA of adenosine released from the heart.Our findings provide evidence that at least two different adenine nucleotide compartments of the heart serve as precursors for the formation of adenosine and cAMP, one characterized by a high, the other by a lower SA. Under normoxic conditions adenosine and cAMP released into the cardiac perfusate are derived mainly from a nucleotide fraction of high SA, which appears to be rather small. During ischemia a second compartment of much lower SA in addition contributes to the formation of adenosine.A preliminary report of part of this work appeared in Biochemistry and Pharmacology of Myocardial Hypertrophy, Hypoxia and Infarction Vol. 7 of Recent advances in studies on cardiac structure and metabolism. (P. Harris, R. J. Bing, A. Fleckenstein, eds.), pp. 171–175. München: Urban & Schwarzenberg 1976A preliminary report of part of this work appeared in Biochemistry and Pharmacology of Myocardial Hypertrophy, Hypoxia and Infarction Vol. 7 of Recent advances in studies on cardiac structure and metabolism. (P. Harris, R. J. Bing, A. Fleckenstein, eds.), pp. 171–175. München: Urban & Schwarzenberg 1976     

Recovery from short term intense exercise: Its relation to capillary supply and blood lactate concentration

Summary Muscle force recovery from short term intense exercise was examined in 16 physically active men. They performed 50 consecutive maximal voluntary knee extensions. Following a 40-s rest period five additional maximal contractions were executed. The decrease in torque during the 50 contractions and the peak torque during the five contractions relative to initial torque were used as indices for fatigue and recovery, respectively. Venous blood samples were collected repeatedly up to 8 min post exercise for subsequent lactate analyses. Muscle biopsies were obtained from m. vastus lateralis and analysed for fiber type composition, fiber area, and capillary density. Peak torque decreased 67 (range 47–82%) as a result of the repeated contractions. Following recovery, peak torque averaged 70 (47–86%) of the initial value. Lactate concentration after the 50 contractions was 2.9±1.3 mmol·l⁻¹ and the peak post exercise value averaged 8.7±2.1 mmol·l⁻¹. Fatigue and recovery respectively were correlated with capillary density (r=−0.71 and 0.69) but not with fiber type distribution. A relationship was demonstrated between capillary density and post exercise/peak post exercise blood lactate concentration (r=0.64). Based on the present findings it is suggested that lactate elimination from the exercising muscle is partly dependent upon the capillary supply and subsequently influences the rate of muscle force recovery. Dr. Tesch was on leave from Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden     

The reproducibility of estimates of critical power and anaerobic work capacity in upper-body exercise

The purposes of this study were to apply the linear power versus inverse of time relationship to high-intensity upper-body exercise and to assess the repeatability of the parameters critical power (CP) and anaerobic working capacity (AWC), using limits of agreement (Bland and Altman 1986). Sixteen active male subjects (aged 20–34 years), performed two sets of five constant-power exercises on an adapted cycle ergometer. There were no significant differences between mean estimates of CP [96 (16) W and 95 (17) W] and AWC [7457 (2011) J and 7608 (1684) J] from the first and second sets of bouts. Despite the lack of systematic bias, there was evidence of large random error. Ratio limits of agreement for time to exhaustion during constant-power exercises suggested that a repeat measurement might be expected in 95% of cases to be between 0.64 and 1.59 times the original measurement. The 95% limits of agreement for CP were –15 W to +17 W. The ratio limits of agreement for AWC suggest that in 95% of cases a repeat measurement might be between 0.57 and 1.67 times the original estimate. The results of this study suggest a poor repeatability of constant-power upper-body exercises to exhaustion, which may contribute to a poor repeatability of CP and AWC determined from the linear power versus inverse of time model. Electronic Publication     

Serum 27E10 antigen: a new potential marker for staging HIV disease.

MRP8 and MRP14 are myeloic related proteins expressed by most circulating and emigrated neutrophils and monocytes. Their composite molecule MRP8/14 (27E10 antigen) was shown to exhibit striking antimicrobial properties. The aim of the present study was to assess the value of MRPs as markers for detection of the different stages of HIV infection (Centres for Disease Control and Prevention, 1993). By employing the ELISA technique we measured serum concentrations of these proteins in samples from 122 HIV patients at the various stages of disease, and the results were compared with those for healthy controls. Serum levels of the heterodimeric molecule 27E10 were significantly increased (P < 0.001) in patients with CDC stages II and III, with the highest levels being in patients with stage III and acute ongoing opportunistic infections. For the single component MRP14, significantly raised levels (P < 0.05) were only found in HIV stage III individuals with acute clinical events. Similar associations were not found for MRP8 alone. Increase was not related to CD4+ cell count. There was a significant correlation between 27E10 antigen serum concentrations and levels of neopterin in patients with HIV stages II and III without acute concurrent illness. Patients being treated with Zidovudine showed no statistically significant variation in levels of 27E10 and its single components MRP8 and MRP14 compared with untreated patients. These findings suggest that elevation of MRP14 levels occurs in HIV+ individuals at later stages post-HIV infection, after the onset of opportunistic infections. 27E10 antigen is concluded to be a potential marker for the different stages of HIV disease.     

Age-dependent cerebral metabolic effects of unilateral nucleus basalis magnocellularis ablation in rats

To investigate the age-dependent functional importance of cholinergic neocortical inputs, and to explore whether cortical cholinergic denervation in aged animals might better model the cerebral metabolic changes of Alzheimer's disease, the effects of unilateral ablation of the nucleus basalis magnocellularis (NBM) on cerebral glucose metabolism were studied in young and aged rats. Regional cerebral metabolic rates for glucose (rCMRglc) were determined, using the [14C]deoxyglucose method, in 48 brain regions of 3- and 24-month old Fischer-344 rats at 3, 7, 14 and 28 days after stereotaxic injection of ibotenate into the right NBM, and in sham-operated animals at 3 and 14 days later. For both ages the peak effect of unilateral NBM ablation occurred 3 days later: in young rats, rCMRglc was significantly reduced (compared to the contralateral side) in all 24 anterior cortical areas examined (mean decline 20%), whereas in aged animals, only 9 of 24 areas showed a significant decline in glucose utilization, and the magnitude of rCMRglc reduction (9%) was smaller. Near complete recovery of rCMRglc occurred by 7 days in young and old rats. We conclude that the basalocortical cholinergic projection plays a smaller role in neocortical function of aged rats, possibly because its tonic activity is reduced. Both young and aged rats undergo cortical metabolic normalization after unilateral NBM ablation; hence the NBM-lesioned aged rat is not a better model of the progressive decline in rCMRglc that occurs in Alzheimer's disease.     

Effects of resistance training in humans on neck muscle performance, and electromyogram power spectrum changes

The purpose of this study was to quantify the neuromuscular cervical adaptations to an 8 week strength training programme. Seven healthy men, with no pathological conditions of the neck, performed a lateral flexion isometric resistance-training programme three times a week. The training sessions consisted of one set of ten contractions, each of 6 s duration, at 60% of the predetermined maximal voluntary isometric torque (MVT_im) (warm-up) and two sets of eight contractions, each of 6 s duration, at 80% MVT_im. The training effects were evaluated in three ways: muscle size, strength and fatigability. The cross-sectional areas (CSA) of the trapezius (TRP) and sternocleidomastoideus (SCM) muscles were determined using a computerised tomographic scanner. Results showed an increase in the CSA of TRP and SCM muscles after training, 8.8% at C5 level and 6.4% at C7 level for SCM muscle and 12.2% at C7 level for TRP muscle. Strength increased significantly under both isometric and isokinetic conditions (35% and 20%, respectively). Muscle fatigability in lateral flexion was quantified during a sustained isometric contraction at 50% of MVT_im. The shift of the mean power frequency of the electromyogram power spectrum density function of SCM muscle toward lower frequencies was less after training (14.6% compared to 6.8%). These results indicate the beneficial effect of a strength-training programme which increases neck muscle size and strength during lateral flexion, and decreases the fatigability of the superficial muscles of the neck. Electronic Publication     

Rapid activation of glycogen synthase and protein phosphatase in human skeletal muscle after isometric contraction requires an intact circulation

The effects of isometric contraction (66% of maximal force) and recovery on glycogen synthase fractional activity (GSF) in human skeletal muscle have been studied. Biopsies were taken from the quadriceps femoris muscle at rest, at fatigue and 5 min postexercise on two occasions: after one of the contractions, the circulation to the thigh was occluded during the 5 min recovery (OCC), and after the other contraction, the circulation was intact (control, CON). During CON, GSF decreased from (mean ± SE) 0.34±0.05 at rest to 0.24±0.02 at fatigue and then increased to 0.74±0.04 at 5 min postexercise; corresponding values for OCC were 0.37±0.04, 0.25±0.04 and 0.48±0.05 (P<0.001 vs. CON for 5 min postexercise only). Compared with the value at fatigue, protein phosphatase activity (PP) increased by 79±16% during CON recovery (P<0.01), whereas no change was observed during OCC recovery. Uridine diphosphate glucose increased by approximately 2.5-fold at fatigue, remained elevated during OCC recovery, but reverted to the preexercise level during CON recovery (P<0.001 vs. OCC recovery). Glucose 6-P increased approximately 5-fold at fatigue and was higher at 5 min postexercise in OCC vs. CON recovery (8.6±1.5 vs. 4.1±0.9 mmol/kg dry wt; P<0.01). It is concluded that the rapid increase in GSF after intense exercise with an intact circulation may be at least partly attributed to an increase in the specific activity of PP. The increase in GSF during recovery in OCC may be at least partly attributed to the high glucose 6-P content in vivo, which enhances the substrate suitability of GS for PP. Thus, separate mechanisms exist for the activation of PP and GS during recovery from intense short term exercise.     

14-3-3σ调控p27抑制Rat1-Akt细胞增殖

目的： 研究腺病毒介导14-3-3·σ（Ad-14-3-3·σ）对Akt过表达Rat1-Akt细胞增殖的影响，并探讨其作用是否通过调控p27而实现。 方法： 通过5-溴-2′脱氧尿嘧啶（BrdU）实验检测Ad-14-3-3·σ对Rat1-Akt细胞增殖的影响，并通过激酶分析法和免疫荧光实验探讨Ad-14-3-3·σ对p27磷酸化水平及其在细胞内定位的影响。 结果： Ad-14-3-3σ转染的细胞BrdU阳性率（45%）低于PBS处理组（100%）或Ad-β-gal转染的对照组细胞（98%）。14-3-3σ可降低磷酸化p27的水平和减少Akt介导的p27在胞浆中的定位。 结论： 转染14-3-3σ基因能抑制Akt过表达细胞株Rat1-Akt增殖，14-3-3σ通过降低Akt激酶磷酸化p27的活性，阻断Akt介导的p27胞浆错位，从而发挥其抑制Rat1-Akt细胞增殖。