Effect of muscular activity on the turnover rate of actin and myosin heavy and light chains in different types of skeletal muscle.

In endurance-trained rats the myosin HC have a more rapid turnover rate than in control animals in all three types of skeletal muscle fibres, but in sprint-trained rats only in fast-glycolytic and fast-oxidative-glycolytic fibres. A comparison of the actin turnover rate in sprint- and endurance-trained animals shows that in both groups there are more rapid turnover rates in all types of muscle fibres in comparison with control rats. During long-lasting exhaustive exercise the turnover rate of myosin HC decreases. Twelve hours after exercise, myosin LC 2 and 3, and actin have a more rapid turnover than in control rats. Changes in the turnover rate of muscle contractile proteins during exercise and the recovery period after exercise reflect the functional conditions of the contractile apparatus in different types of skeletal muscle fibres and have a physiological significance.     

Can impairments of thyroid function test affect prognosis in patients with respiratory failure?

Thyroid function test (TFT) impairments can be detected in extrathyroidal dysfunction, primarily in chronic obstructive pulmonary disease (COPD) with acute respiratory failure (RF). The aims of this study were to: (i) evaluate TFT impairments in patients with RF, (ii) compare TFT results to a control group without RF and (iii) assess the effects of thyroid dysfunction on clinical outcome and prognosis of RF. The TFT parameters were assessed in 65 patients (65.0 +/- 10.0 years, 49 males) with RF and compared to 18 patients (64.4 +/- 9.8 years, 13 males) with lung disease and no RF (p> 0.05). Arterial blood gas analysis, free T3 (FT3), free T4 (FT4) and TSH levels were all measured. The impairments of TFT were demonstrated in 34 (52.3%) patients with RF and 8 (44.4%) patients without RF (p> 0.05). The most common finding was a decrease in at least one of the TFT parameters in both groups (43.1% vs. 44.4%, respectively). In RF group, there was no significant association between TFT results and gender, age, diagnosis and co-morbid disease. However, need for invasive mechanical ventilation was higher both in patients with low FT3 and low FT4 when compared to those with normal TFT results (p= 0.001 and p= 0.003, respectively). In-hospital mortality rate was also higher both in the patients with low FT3 and low FT4 than the others (p= 0.006 and p= 0.01, respectively). We conclude that TFT impairments are not observed more frequently in patients with RF when compared to the patients without RF. However, low FT3 and FT4 levels increase the rates of invasive mechanical ventilation and mortality.     

The levels of asymmetric dimethylarginine, homocysteine and carotid intima-media thickness in hypercholesterolemic children

The aim of this study was to examine the intima-media thickness (IMT) of carotid arteries and endothelial function parameters such as plasma asymmetric dimethylarginine (ADMA) and homocysteine levels in hypercholesterolemic children and to investigate the relations of these parameters with hypercholesterolemia. Fifty-seven hypercholesterolemic and 37 healthy children were included in the study. Hypercholesterolemia was defined as 155 mg/dl and above for low-density lipoprotein (LDL)-cholesterol. Plasma concentrations of ADMA and homocysteine were measured and the measurement of carotid IMT was determined. Both carotid IMT and plasma ADMA levels were significantly higher in hypercholesterolemic children than healthy children (p<0.01). No significant difference was determined in homocysteine concentration between hypercholesterolemic children and the control group (p>0.05). No significant correlation was observed between lipid profiles and the levels of ADMA and homocysteine. However, a significant positive correlation was found between carotid IMT and total and LDL-cholesterol levels and between the levels of ADMA and LDL-cholesterol. In conclusion, the progressive increase in ADMA levels and carotid IMT and the positive relationship between carotid IMT and serum cholesterol levels support that plasma ADMA levels and carotid IMT can be indicators of early atherosclerosis in hypercholesterolemic children.     

Serum vascular endothelial growth factor,insulin-like growth factor-1 and aflibercept levels in retinopathy of prematurity

Japanese Journal of Ophthalmology - To evaluate the serum levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) after intravitreal injection of aflibercept...     

Influence of iodine supplementation on serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) levels in severe iodine deficiency

Iodine deficiency is an important public health problem worldwide. In addition to severe consequences such as brain damage, developmental delay, deficits in hearing and learning, it also has a negative impact on growth. The negative impact of severe iodine deficiency (SID) on insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) was shown previously. In this study we aimed to analyze the impact of iodine supplementation on growth and growth factors of children with SID. One hundred and four children (63 boys and 41 girls) aged 5-15 years participated in the study. Height standard deviation scores (HSDS), and serum levels of IGF-I and IGFBP-3 were assessed both before and six months after a single dose of iodized oil. Serum levels of free thyroxine (FT4) and thyroid stimulating hormone (TSH) were also analysed to investigate the mechanisms by which alterations of iodine status may influence growth. Pubertal children had lower HSDS six months after iodine supplementation, while that of prepubertal children remained unchanged. IGF-I and IGFBP-3 levels decreased significantly and FT4 levels were suppressed six months after the supplementation, while TSH was normalized. These findings suggest a negative impact of iodine supplementation on growth factors in the short-term, which may be a direct effect of iodine repletion or an indirect effect caused by alterations in thyroid function. It may also be related to the method of supplementation used. Further studies are necessary to resolve these issues, as well as to examine the impact of iodine supplementation on growth in the long-term.     

Causes of increased renal medullary echogenicity in Turkish children

The primary disorders of 50 children with increased renal medullary echogenicity on renal ultrasound were studied; 28 girls and 22 boys aged from 1 month to 16 years were classified into four groups based on underlying disease and ultrasound findings. Group 1 was composed of 17 patients with distal renal tubular acidosis (34%); intense echoes throughout the pyramid were predominant. Group 2 consisted of 14 patients with vitamin D toxicity (28%) and an intense echogenic rim around the pyramids. Group 3 included 10 patients with different types of tubulopathies. A slight hyperechogenic rim around the sides and tip of the medullary pyramids was detected. Group 4 was made up of 9 patients with rare underlying conditions. Abdominal X-rays detected medullary calcinosis in only 12 (24%) of the total 50 patients. Ultrasonography appears to be an important tool in the early diagnosis of increased renal medullary echogenicity and medullary nephrocalcinosis.