The repeated bout effect of reduced-load eccentric exercise on elbow flexor muscle damage

In this study we investigated the extent to which an initial eccentric exercise consisting of two (2ECC) or six maximal eccentric actions (6ECC) of the elbow flexors would produce a similar effect to 24 maximal eccentric actions (24ECC), on a second bout of 24ECC performed 2 weeks later. Male students (n=34) were assigned to one of three groups, and with their non-dominant arm performed either 2ECC (n=12), 6ECC (n=10), or 24ECC (n=12) as a first bout of exercise. Two weeks later all groups performed 24ECC. Maximal isometric strength, range of motion, upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration were assessed before, immediately after, and for 4 days after exercise. Changes in all variables were compared between the bouts and groups by a two-way repeated measures analysis of variance. All variables changed significantly (P<0.05) after 2ECC, 6ECC, and 24ECC, but the amount of change after 2ECC and 6ECC was significantly smaller (P<0.05) than both 6ECC and 24ECC, and 24ECC, respectively. After the second bout, the 6ECC and 24ECC groups showed a profound repeated bout effect, and no significant differences were found between the groups. All variables except muscle soreness were significantly (P<0.05) larger after the second bout for the 2ECC group, however the changes observed after 24ECC were significantly smaller (P<0.01) than those observed after the first 24ECC of the 24ECC group. These results suggest that it is not necessary to conduct a high number of eccentric actions in the first bout to elicit a repeated bout effect in a subsequent bout performed some time later. Electronic Publication     

A computer program for evaluating the hydrodynamic parameters of a macromolecule in solution for any given value of its axial dimensions

A FORTRAN IV algorithm is given for determining the hydrodynamic parameters of a macromolecule in solution for any specified value of the two axial ratios ($\text{a}\text{b}$, $\text{b}\text{c}$) of the equivalent triaxial ellipsoid model of semi-axes a ≥ b ≥ c for its gross conformation.     

Myoglobin distribution in the heart of growing rats exposed to a simulated altitude of 3500 m in their youth or born in the low pressure chamber

Summary Reynafarje's (1963) spectrophotometric method was modified for the study of myoglobin concentration in rat hearts. The influence of age and body weight was evaluated and the age was found to be better correlated with myoglobin concentration than the weight. The influence of simulated altitude of 3500 m was studied in animals exposed to hypoxia at the age of about 34 days and in animals born in the low pressure chamber. In the first group a higher myoglobin concentration was found but only in the right ventricle, together with unilateral hypertrophy, as compared with control animals. In the group of animals born at simulated altitude a severe cardiomegaly developed which was most pronounced in the right ventricle. The myoglobin concentration in the hearts from this group was unchanged in the right ventricle and was lower in the left ventricle and septum.     

CONGENITAL ALVEOLAR RHABDOMYOSARCOMA WITH MULTIPLE SKIN METASTASES: Report of a Case

A rare case of congenital alveolar rhabdomyosarcoma revealing multiple skin metastases in a female neonate is reported. At birth, a ping-pong ball-sized tumor on the neck and a tumor the size of a little finger end on the chin were noticed. Then, multiple skin tumors over the whole body occurred soon after birth. A biopsied small skin tumor was at first interpreted as being compatible with metastatic congenital neuroblastoma. However, immunohisto-chemical and electron microscopic findings revealed positive immunoreactivity for myoglobin in a few tumor cells and the presence of a few rhabdomyoblasts among poorly differentiated tumor cells, resulting in a final diagnosis of alveolar rhabdomyosarcoma. Therefore, it should be emphasized that in cases of round cell tumor, immunohistochemical and ultrastructural studies are imperative in order to identify the tumor and differentiate it from other forms, including rhabdomyoblastoma, neuroblastoma, Ewing's sarcoma, malignant lymphoma, and small cell carcinoma. ACTA PATHOL JPN 38: 241–248, 1988.     

Levels of serum creatine kinase and myoglobin in women after two isometric exercise conditions

Summary The purpose of this study was to measure serum creatine kinase (CK) activity and serum myoglobin (MG) concentrations in women after two unilateral isometric knee extension exercises. Forty maximal voluntary contractions (MVC) were held for 10 s, with either a 5 s (10∶5) or 20 s 10∶20 exercise (349.4±66.1 mU · ml⁻¹) and 6 h and MG values were measured pre, 0, 3, 6, and 18 h post exercise. For CK, the highest post exercise values were observed at 6 h following the 10∶20 exercise (349.4±66.1 mU · ml⁻¹) and 6 h following the 10∶5 exercise (194.1±18.6 mU · ml⁻¹). For MG, the highest values were found 3 h after the 10∶20 exercise (148.9±61.7 ng · ml⁻¹) and 6 h after the 10∶5 exercise (67.3±10.9 ng · ml⁻¹). Serum CK and MG levels were significantly greater (p<0.01) after the 10∶20 exercise bout. The data demonstrate that CK and MG values for women increase significantly after isometric exercise. Since greater tension levels were maintained during the 10∶20 exercise it is hypothesized that increased serum CK and MG values after isometric exercise may be related to the tension generated by the contracting muscle.     

Effects of hypoxia on capillary density and fiber composition in rat skeletal muscle

Summary Capillary density, fiber composition and myoglobin concentration were determined in skeletal muscle of Sprague-Dawley female rats. P_IO₂ for control (C) rats was 123 mm Hg; for hypoxic (H) rats the O₂ concentration in air was lowered to 12.6% (P_IO₂=73 mm Hg) over 4 days and then kept at this level for 39 days. Body weight (BW) in C rats went from 182 to 258 g in 6 weeks. H rats showed an initial 13 g drop in BW but later gained weight at the same rate. A difference of 20 g was maintained between C and H rats. Five groups of about 10 rats each (3 C and 2 H) were studied by histochemistry using frozen samples from the tibialis anterior, gastrocnemius (medial head) and soleus muscles. 20 m slices, cut transversely, were treated for alkaline phosphatase and ATPase after preincubation at pH's of 3.8 to 9.4 in order to visualize capillaries and typify fibers. In both C and H rats, capillary density decreased at the same rate with increasing BW, as a consequence of the increase in the size of the fibers resulting from growth. At the same BW capillary densities for a given muscle were not statistically different. No consistent differences in fiber composition were found in the soleus after exposure to hypoxia. In the gastrocnemius and the tibialis anterior, however, the percentage population of white fibers tended to be higher in the H rats than in the C rats, while the population of red fibers decreased. Myoglobin concentration was higher in the soleus, a muscle with a preponderant intermediate fiber population, than in the other two muscles. Hypoxia did not systematically affect myoglobin concentration.Supported by GRS 523 and HL 18145, N.I.H.Supported by a fellowship from the Rockefeller Fndn.     

心肌肌钙蛋白I和肌红蛋白对急性心肌梗死的诊断价值及预后评价

目的　探讨血清心肌损伤标志物心肌肌钙蛋白 I(c Tn I)和肌红蛋白 (Mb)对急性心肌梗死 (AMI)的诊断价值及预后评价。方法　连续搜集了急性胸痛的患者 12 1例 ,其中 AMI患者 6 3例 ,非 AMI患者 5 8例 ,对上述病例进行血清 c Tn I、Mb和肌酸激酶同工酶 (CK- MB)测定 ,观察其变化规律 ,分组比较心脏事件发生率。结果　 AMI发病 6 h以内 ,Mb首先升高 ,敏感性达 87.1%。发病 18～ 2 4 h,c Tn I敏感性达 10 0 .0 % ,且于发病第 5日仍维持敏感性达 6 1.1%。入院即刻 Mb敏感性 92 .1% ,高于 c Tn I 5 5 .6 %和 CK- MB 5 7.1% ;Mb特异性82 .8% ,低于 c Tn I96 .7%。入院次日晨 c Tn I敏感性 96 .8% ,高于 Mb6 1.9%和 CK- MB77.8%。AMI患者入院即刻 c Tn I增高组与正常组心脏事件发生率分别为 2 2 .9%和 3.6 % (P<0 .0 5 ) ,校正基线特征等多变量因素后 ,c Tn I是 AMI患者发生心脏事件独立的危险性预测因子 ,OR值 1.171(P<0 .0 5 )。结论　 c Tn I联合 Mb是诊断AMI的良好指标 ,其灵敏性和特异性能得到最佳体现。c Tn I亦有助于中后期 AMI的诊断。c Tn I是 AMI患者发生心脏事件独立的危险性预测因子     

Influence of glucose-lowering rate on CKMB and myoglobin serum levels in type-2 diabetes patients with coronary heart disease

Objective

To analyze the level of creatine kinase isoenzyme (CKMB), myoglobin, to explore the influence of different glucose-lowering rate on cardiac enzyme in type 2 diabetes mellitus patients with coronary heart disease (T2DMC), to search for the rational glucose-lowering rate.

Methods

A total number of 293 type 2 diabetic patients who were hospitalized in the First Affiliated Hospital of Harbin Medical University from May 2008 to December 2009 were recruited. Two groups were divided according to the coronary angiography. 142 subjects of type 2 diabetes mellitus (T2DM) and 151 subjects of T2DMC received intensive glucose therapy. After CKMB and myoglobin being measured, variation and correlation factors were evaluated.

Results

In T2DM group, the level of CKMB was significantly lower at follow-up than that before intensive therapy. Then, we got four subgroups according to the glucose-lowering rate. In T2DM group, when the fasting or postprandial glucose-lowering rate was no more than 6 mmol L⁻¹ d⁻¹, the level of CKMB and myoglobin were significantly lower than that before intensive therapy (P < 0.05). When the fasting glucose-lowering rate is faster than 6 mmol L⁻¹ d⁻¹, the level of CKMB is significantly higher after intensive therapy than that before glucose-lowering (P < 0.05). In T2DMC group, when the fasting or postprandial glucose-lowering rate was not more than 4 mmol L⁻¹ d⁻¹, the level of CKMB and myoglobin was significantly lower than that before intensive therapy (P < 0.05, P < 0.01). When the fasting glucose-lowering rate was faster than 4 mmol L⁻¹ d⁻¹, the level of CKMB and myoglobin was significantly higher at follow-up than that before intensive therapy (P < 0.05). Before intensive therapy, high density lipoprotein cholesterol (HDL-C) has a negative linear regression relationship with CKMB (P < 0.01). Low density lipoprotein cholesterol (LDL-C) and triglyceride (TG) and glycosylated hemoglobin A1c (HbA1c) have a positive linear regression relationship with CKMB (P < 0.05). HDL-C has a negative linear regression relationship with myoglobin (P < 0.01). LDL-C and TG have a positive linear regression relationship with myoglobin (P < 0.01).

Conclusions

T2DM patients, no matter with CHD or not, all have a rational fasting glucose-lowering rate; the fasting glucose-lowering rate is more susceptible to myocardial damage anticipation than the postprandial glucose-lowering rate.     

急诊联合快速检测肌红蛋白及心肌肌钙蛋白Ⅰ对急性心肌梗死的早期诊断意义

目的 探讨肌红蛋白(Mb)与心肌肌钙蛋白Ⅰ(cTnI)急诊联合快速检测对急性心肌梗死(AMI)的早期诊断价值.方法 对胸痛发作2～6 h或临床疑为AMI的急诊病者86例,急诊采取静脉全血用Mb、cTnI联合试板测定Mb、cTnI和Mb cTnI,分析其诊断AMI的敏感性、特异性、准确性,并将阳性预测值与阴性预测值作比较.结果 Mb敏感性为96.1%,阴性预测值为91.7%明显高于cTnI的88.2%和85.2%(P＜0.05或P＜0.01);但cTnI的特异性97.1%,准确性91.9%和阳性预测值97.8%,分别高于Mb的62.9%、82.6%和79.0%(P＜0.05或P＜0.01);采用Mb cTnI联合检测其特异性、阳性预测值和阴性预测值均达100%,高于单独Mb及cTnI的检测(P＜0.01).结论 Mb和cTnI联合快速检测可使其敏感性和特异性得到最佳体现,对AMI的早期诊断具有重要的价值,并具有快速、准确、方便、经济等优点,在急诊的应用有较好的前景.     

A novel method for detection of nitric oxide binding sites by using a chemiluminescence-headspace gas technique

Nitric oxide (NO) is important in many physiological, pharmacological, and pathological processes. According to current concepts, guanylyl cyclase is considered to be a receptor for NO in vascular and nonvascular smooth muscle and other tissues. Since there are no suitable radioisotopes of oxygen and nitrogen available for conventional radioligand-receptor binding studies for NO, a novel method was developed to identify NO binding site(s). A chemiluminescence-headspace gas assay was utilized to measure the sequestration of NO in biological systems, and this was used as an index of NO binding. In the present report, myoglobin (a hemoprotein, Mb) was used as a prototype macromolecule to develop the binding assay for subsequent application to studies of putative NO receptors. Solutions containing various concentrations of Mb were incubated with NO in sealed micro-Fernbach flasks at 37°C in an argon atmosphere for 30 min; NO remaining in the headspace gas was analyzed by means of the chemiluminescence assay. The magnitude of NO sequestration was dependent on Mb concentration, and 5 nM Mb was the lowest Mb concentration for which NO sequestration was measurable. Application of the method to the measurement of NO sequestration by bovine serum albumin (BSA) and pulmonary artery medial layer homogenate (BPA-M) revealed that the lowest BSA concentration at which NO sequestration was measurable was 1.6 μM, which was 320 times greater than that for Mb. Applicability of the method to address the question of putative NO receptors was indicated by significant NO sequestration after incubation with 20% (w/v) homogenate of BPA-M, which is responsive to NO and putative NO prodrugs.