Type IIx muscle fibers are related to poor body composition, glycemic and lipidemic blood profiles in young females: the protective role of type I and IIa muscle fibers.

PURPOSE: The aim of the present study was to investigate the association between muscle fiber composition, body composition, resting glycemic-lipidemic blood profiles, in apparently healthy, young, active females. METHODS: Thirty-four young healthy female volunteers were allocated into two groups, depending on their Vastus Lateralis type IIx muscle fibers percent cross-sectional area (%CSA; H: high type IIx %CSA; L: low type IIx %CSA). Body composition was determined via dual-energy X-ray absorptiometry. Venous blood samples were collected for the determination of resting serum glucose, Insulin, Apo-A1, HOMA-IR, triglycerides (TG), total cholesterol (TC), High-density lipoprotein (HDL-C), and Low-density lipoprotein (LDL-C) concentrations. Nutritional intake was also evaluated. RESULTS: Individuals of the H group have significantly higher body mass, body fat percentage-mass, and resting blood indices of glycemic and lipidemic profiles, compared to those of L group (p < 0.001). Increased type IIx and low type I, IIa muscle fibers %CSAs were linked with poorer body composition, glycemic and lipidemic blood profiles (r: - 0.722 to 0.740, p < 0.001). Linear regression analyses revealed that the impact of muscle fibers %CSA (B coefficients ranged between - 0.700 and 0.835) on the above parameters, was at least, of the same or even of greater magnitude as that of body composition and daily nutritional intake (B: - 0.700 to 0.666). CONCLUSION: Increased type IIx and low Type I, IIa %CSAs are associated with poorer body composition and glycemic-lipidemic profiles in young healthy females. The contribution of the muscle fiber %CSA on health status seems to be comparable to that of nutrition and body composition.

Reliability of resting intramuscular fiber conduction velocity evaluation.

Characterization of the least number of muscle fibers analyzed for a quick and reliable, evaluation of intramuscular fiber conduction velocity (MFCV) is of importance for sport scientists. The aim of this study was to evaluate the reliability of vastus lateralis' intramuscular MFCV measuring either 25 or 50 different muscle fibers per participant, as well as to compare intramuscular MFCV measured in 25 (C25 ), 50 (C50 ), or 140 (C140 ) muscle fibers. Resting vastus lateralis' MFCV was measured in 21 young healthy males (age 22.1±2.4 years) using intramuscular microelectrodes in different days. Test-retest reliability of MFCV's parameters was calculated for C25 and C50 , while MFCV was compared among C25 , C50 , and C140 . Significant differences of MFCV parameters were observed between C25 condition and those of C50 and C140 . The differences in MFCV values between conditions C50 and C140 were non-significant. A close correlation was found for MFCV between C50 and C140 (r=0.884-0.988, P=.000). All reliability measures of MFCV measured with 50 fibers were high (eg, ICC=0.813-0.980, P=.000), in contrast to C25 (eg, ICC=0.023-0.580 P>.05). In conclusion, an average of 50 different fibers per subject is sufficient to provide a quick and reliable intramuscular evaluation of vastus lateralis MFCV.

Effects of high-intensity interval cycling performed after resistance training on muscle strength and hypertrophy.

Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P < 0.05) and REC (type I: 10.0 ± 2.7%, type IIA: 14.8 ± 4.3% type IIX: 20.8 ± 6.0%, P < 0.05). In contrast, RFD decreased and fascicle angle increased (P < 0.05) only after REC. Capillary density and estimated aerobic capacity increased (P < 0.05) only after REC. These results suggest that high-intensity interval cycling performed after heavy-resistance exercise may not inhibit resistance exercise-induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes.

Body composition analysis in late-onset Pompe disease.

Pompe disease is an inherited metabolic disorder caused by α-glycosidase deficiency. The adult onset form is mainly characterized by progressive proximal muscle weakness and respiratory dysfunction. The aim of the present study is to evaluate body composition in adult patients before and after enzyme replacement therapy (ERT). Body composition was examined at baseline by means of dual x-ray absorptiometry (DXA) in nine adult patients and after different time periods in six of them who received ERT. Total BMD (bone mineral density) was initially mildly decreased in two patients, while femoral neck BMD was decreased in five patients. On the other hand fat mass was increased in the majority of patients, while body mass index (BMI) was high in four. ERT administration did not seem to induce obvious BMD changes in any patient. Conclusively, the greater femoral neck BMD involvement may be attributed to the lower mechanical load applied by the selectively weakened muscles, whereas the increased fat mass may be the result of metabolic and nutritional derangement.

Effect of pulmonary rehabilitation on muscle remodelling in cachectic patients with COPD.

It is known that non-cachectic patients with chronic obstructive pulmonary disease (COPD) respond well to pulmonary rehabilitation, but whether cachectic COPD patients are capable of adaptive responses is both important and unknown. 10 cachectic and 19 non-cachectic COPD patients undertook high-intensity cycling training, at the same relative intensity, for 45 min x day(-1), 3 days x week(-1) for 10 weeks. Before and after rehabilitation vastus lateralis muscle biopsies were analysed morphologically and for the expression of muscle remodelling factors (insulin-like growth factor (IGF)-I, myogenic differentiation factor D (MyoD), tumour necrosis factor (TNF)-alpha, nuclear factor (NF)-kappaB and myostatin) and key components of ubiquitin-mediated proteolytic systems (muscle ring finger protein (MURF)-1 and Atrogin-1). Rehabilitation improved peak work-rate and the 6-min walk distance similarly in non-cachectic (18+/-3% and 42+/-13 m, respectively) and cachectic (16+/-2% and 53+/-16 m, respectively) patients, but quality of life only improved in non-cachectic COPD. Mean muscle fibre cross-sectional area increased in both groups, but significantly less in cachectic (7+/-2%) than in non-cachectic (11+/-2%) patients. Both groups equally decreased the proportion of type IIb fibres and increased muscle capillary/fibre ratio. IGF-I mRNA expression increased in both groups, but IGF-I protein levels increased more in non-cachectic COPD. MyoD was upregulated, whereas myostatin was downregulated at the mRNA and protein level only in non-cachectic patients. Whilst rehabilitation had no effect on TNF-alpha expression, it decreased the activation of the transcription factor NF-kappaB in both groups by the same amount. Atrogin-1 and MURF-1 expression were increased in cachectic COPD, but it was decreased in non-cachectic patients. Cachectic COPD patients partially retain the capacity for peripheral muscle remodelling in response to rehabilitation and are able to increase exercise capacity as much as those without cachexia, even if they exhibit both quantitative and qualitative differences in the type of muscle fibre remodelling in response to exercise training.

Texture analysis of perimenopausal and post-menopausal endometrial tissue in grayscale transvaginal ultrasonography.

The aim of this study was to investigate the feasibility of texture analysis in characterizing endometrial tissue as depicted in two-dimensional (2D) grayscale transvaginal ultrasonography. Digital transvaginal ultrasound endometrial images were acquired from 65 perimenopausal and post-menopausal women prior to gynaecological operations; histology revealed 15 malignant and 50 benign cases. Images were processed with a wavelet-based contrast enhancement technique. Three regions of interest (ROIs) were identified (endometrium, endometrium plus adjacent myometrium, layer containing endometrial-myometrial interface) on each original and processed image. 32 textural features were extracted from each ROI employing first and second order statistics texture analysis algorithms. Textural features-based models were generated for differentiating benign from malignant endometrial tissue using stepwise logistic regression analysis. Models' performance was evaluated by means of receiver operating characteristic (ROC) analysis. The best logistic regression model comprised seven textural features extracted from the ROIs determined on the processed images; three features were extracted from the endometrium, while four features were extracted from the layer containing the endometrial-myometrial interface. The area under the ROC curve (A(z)) was 0.956+/-0.038, providing 86.0% specificity at 93.3% sensitivity using the cut-off level of 0.5 for probability of malignancy. Texture analysis of 2D grayscale transvaginal ultrasound images can effectively differentiate malignant from benign endometrial tissue and may contribute to computer-aided diagnosis of endometrial cancer.

Neuromuscular control and performance in shot-put athletes.

AIM: The aim of this study was to investigate the relationship between the activation level of certain protagonist muscles of the upper and lower body during the shot-put with the shot-put performance in skilled athletes. METHODS: Eight experienced right-handed shot-putters, performed the shot-put with the linear technique. They also performed a maximum (1RM) squat and a 1RM incline bench-press strength test. Electromyographic (EMG) signals were recorded from the m. quadriceps vastus lateralis (VL), m. gastrocnemius internus, m. pectoralis major (PEC) and the m. triceps brachii (TRI) of the right side during all efforts. The level of EMG during the shot-put was normalized relatively to that measured during the respective maximum strength test. RESULTS: Shot-put performance was significantly correlated with 1RM squat (r=0.76, P<0.05) and 1RM bench-press (r=0.75, P<0.05) as well as with the average EMG from VL and PEC after taking the power position (r=0.91, P<0.01 and r=0.75, P<0.05, respectively). A close negative relationship was also found between shot-put performance and the time to reach peak activation of right TRI during the explosive strike of the throwing arm (r=-0.70, P<0.05). CONCLUSION: These results suggest that, besides the importance of absolute muscle strength, an important parameter for shot-put performance is the level of activation of the VL and the PEC during the delivery phase. Furthermore, these data suggest that the TRI should be activated fast in order to be an effective contributor to the shot-put performance.

Upper body training and the triceps brachii muscle of elite cross country skiers.

This study aimed at evaluating whether addition of extensive upper body training in well-trained cross country skiers induces an adaptation of the triceps brachii (TB) muscle and whether this affects performance. Muscle biopsies were obtained from TB muscle in six male elite cross country skiers before and after 20 weeks of increased upper body training. The cross-sectional area of type I and IIA fibers increased by 11.3% and 24.0%, respectively, and so did the number of capillaries per fiber (2.3-3.2) (all P<0.05). SDS-polyacrylamide electrophoresis revealed in single fibers that the number of fibers expressing myosin heavy chain (MHC) type I isoform decreased from 68.7% to 60.9% (P<0.05), MHC I/IIA isoform was unaltered, while MHC IIA fibers increased from 21.6% to 35.7% and the 4.8% MHC IIA/IIX disappeared with the training (both P<0.05). Citrate synthase and 3-hydroxyacyl coenzyme A dehydrogenase activities increased by 23.3% and 15.4%, respectively, and double poling 10 km time-trial by 10.4% (all P<0.05). The values for TB are similar to what has been demonstrated for leg muscles after exercise training. The subjects who demonstrated the largest improvement in performance exhibited the largest muscle adaptation, which, in turn, was related to the pre-maximal oxygen uptake.

Brain MRI findings in cirrhotic patients: correlation with Doppler US hepatic flow parameters.

BACKGROUND/AIMS: To determine the relationship of basal ganglia alterations demonstrated on brain MRI and clinical presentation, evaluated with Child-Pugh score, using Color Doppler Ultrasonography parameters of portal hemodynamics in cirrhotic patients with signs of portal hypertension. METHODOLOGY: Twenty randomly selected cirrhotic patients (16 males and 4 females with a mean age of 63.6+/-8.9 years) classified according to Child-Pugh score (grade A=16 patients, grade B=4), were submitted to Color Doppler US evaluation of hepatic flow and brain MRI. The obtained flow parameters were: PVD, PVCSA, MPVF, MPVFV, HAD, MHAF, hepatic artery RI, CI and MHI. The basal ganglia signal intensity, on T1-weighted images on brain MRI was evaluated both qualitatively (normal, mild, moderate and severe) and quantitatively with the ROI method. RESULTS: Among Color Doppler parameters, only the CI exhibited a modest correlation with the Child's clinical score (p for linear trend by ANOVA <0.05). Subjective MRI grading demonstrated an excellent correlation with the qualitative assessment of signal density (Spearman p=0.95, p<0.01). When signal intensity on T1-weighted images was analyzed as a continuous variable with normal distribution and ultrasonographic parameters as possible determinants, the portal vein diameter (PVD) and consequently the cross-sectional area (PVCSA) emerged as the sole predictor of MR signal intensity (Pearson's r=0.58, p=0.01). CONCLUSIONS: Although this is a preliminary study and further research should be performed including a larger number of patients, it suggests that Color Doppler US might play a prognostic role in predicting hepatocellular dysfunction and hepatic encephalopathy.

Common carotid artery intima media thickness and post-stroke cognitive impairment.

BACKGROUND AND PURPOSE: Acute stroke and other forms of cerebrovascular disease are well-recognized causes of cognitive impairment. Common carotid artery intima media thickness (CCA-IMT) has been associated with certain forms of cerebrovascular disease, but its association with cognitive impairment of vascular origin has not been elucidated. The purpose of this study was to investigate whether CCA-IMT is associated with cognitive impairment 1 year after an acute ischemic stroke. METHODS: A total of 171 consecutive patients with the first ever stroke (mean age 66+/-11.5, 41% female) underwent carotid ultrasonography during hospitalization. Demographic data, vascular risk factors and presenting stroke features were also recorded. One year later, patients' cognitive performance and depression were assessed using the Mini-Mental State Examination (MMSE), and the Montgomery Asberg Depression Rating Scale (MADRS). RESULTS: Cognitive impairment (MMSE score<24) was found in 67 (39%) of the 171 patients. CCA-IMT was significantly associated with cognitive impairment, and this association remained unchanged (OR 1.94; 95% CI 1.19-3.18) after adjustment for demographic data, vascular risk factors, stroke features, other carotid ultrasonography measurements and depression. Older age, low education level, large hemispheric lesions, hyperdense carotid plaques and depression were also independently associated with post-stroke cognitive impairment. CONCLUSIONS: In this study, CCA-IMT was independently associated with cognitive impairment 1 year after an acute ischemic stroke, and thus, it might help with the screening of stroke patients at risk of cognitive impairment.

Is the common carotid artery intima-media thickness associated with functional outcome after acute ischaemic stroke?

BACKGROUND: Common carotid artery intima-media thickness (CCA-IMT) is an independent and early marker of generalised atherosclerosis. Brain affected by atherosclerosis may be more vulnerable to an ischaemic insult. OBJECTIVE: To investigate the association between CCA-IMT and functional outcome after an acute ischaemic stroke. DESIGN: Prospective cohort analysis. METHODS: 284 consecutive patients (mean (SD) age, 68.7 (12.7) years, 126 (44%) female) with an acute ischaemic stroke had carotid ultrasonography, carried out by a single operator. Demographic data, vascular risk factors, initial stroke severity, and brain imaging findings were recorded. Outcome was assessed at seven days from stroke onset, at discharge from hospital, and at one year post-stroke. RESULTS: CCA-IMT was not significantly associated with adverse short or long term functional outcome in univariate analysis, or after adjustment in a multivariate logistic regression analysis for demographic data, initial stroke severity, conventional vascular risk factors, and the characteristics of the ischaemic lesion. Age and initial stroke severity were the only independent predictors of outcome. CONCLUSIONS: CCA-IMT was not associated with adverse functional outcome after an ischaemic stroke. Adding CCA-IMT in a prediction model for stroke outcome would probably not improve the power of the model.

Relationship between shot put performance and triceps brachii fiber type composition and power production.

It is commonly accepted that shot put performance is mainly determined by the ability of the lower body to produce power. The purpose of the present study was to investigate the relationship between shot put performance and triceps brachii muscle fiber type composition and strength capacity. Thirteen male physical education students were selected to participate in the study based upon their shot put performance after 5 weeks of shot put technique instruction. At the completion of this technique-instruction period, they performed the following tests: shot put with a 6-kg shot, isokinetic torque measurements of the elbow extensors at 0, 0.52, 1.04, 1.57, 2.09, 3.14, and 4.19 rad.s(-1), maximal strength (1 RM) and explosive-throwing bench-press tests, one-arm seated shot put with 1-, 2-, 3-, 4-, 5- and 6-kg shot. Whole-body and dominant upper-arm bioimpedance measurements were used to estimate whole-body and upper-arm muscle mass. Muscle biopsy samples from the long head of the dominant triceps brachii were obtained and analyzed for fiber type composition with ATPase histochemistry. Shot put performance was significantly correlated with type II fiber area ( r=0.70, P<0.01), one-arm seated shot put (range r=0.60 to r=0.79, P<0.05), elbow extensors' isokinetic torque (range r=0.65 to r=0.78, P<0.05), bench-press tests ( r>0.86, P<0.01) and estimated arm muscle cross-sectional area ( r=0.68, P<0.05). These results suggest that fiber type composition and the functional capacity of triceps brachii muscle (e.g., isokinetic torque) explain a part of shot put performance. The magnitude of the correlation coefficients between shot put and the upper-body power tests suggests that other body parts (e.g., lower extremities) may play a significant role in this event.

Distribution of the lactate/H+ transporter isoforms MCT1 and MCT4 in human skeletal muscle.

The profiles of the lactate/H+ transporter isoforms [monocarboxylate transporter isoforms (MCT)] MCT1 and MCT4 (formerly MCT3 of Price, N. T., V. N. Jackson, and A. P. Halestrap. Biochem. J. 329: 321-328, 1998) were studied in the soleus, triceps brachii, and vastus lateralis muscles of six male subjects. The fiber-type compositions of the muscles were evaluated from the occurrence of the myosin heavy chain isoforms, and the fibers were classified as type I, IIA, or IIX. The total content of MCT1 and MCT4 was determined in muscle homogenates by Western blotting, and MCT1 and MCT4 were visualized on cross-sectional muscle sections by immunofluorescence microscopy. The Western blotting revealed a positive, linear relationship between the MCT1 content and the occurrence of type I fibers in the muscle, but no significant relation was found between MCT4 content and fiber type. Moreover, the interindividual variation in MCT4 content was much larger than the interindividual variation in MCT1 content in homogenate samples. The immunofluorescence microscopy showed that within a given muscle section, the MCT4 isoform was clearly more abundant in type II fibers than in type I fibers, whereas only minor differences existed in the occurrence of the MCT1 isoform between type I and II fibers. Together the present results indicate that the content of MCT1 in a muscle varies between different muscles, whereas fiber-type differences in MCT1 content are minor within a given muscle section. In contrast, the content of MCT4 is clearly fiber-type specific but apparently quite similar in various muscles.

Increase in the degree of coexpression of myosin heavy chain isoforms in skeletal muscle fibers of the very old.

Myosin heavy chain (MHC) isoform composition was determined in 2264 single skeletal muscle fibers from vastus lateralis muscle of a group (n = 12) of very old subjects (average age, 88 years). The number of fibers containing only MHC I, IIA, or IIX was 19.9%, 27.2%, and 0.3%, respectively. Surprisingly, 28.5% of the fibers displayed coexpression of both MHC I and IIA, a phenotype that is present in younger adults in very small percentages. Among these fibers coexpressing MHC I and IIA, the majority had a dominant expression of MHC I. Additionally, a small number of fibers coexpressing MHC I and IIX without any MHC IIA, and fibers co-expressing all three isoforms were observed. Altogether, 52.6% of all fibers examined in these very old subjects coexpressed two or three MHC isoforms. The present study provides evidence that advanced age leads to a significant elevation of skeletal muscle fibers displaying coexpression of two MHC isoforms and that a separation into slow and fast fibers in very old individuals may therefore be somewhat misleading. The clinical significance of the elevated number of fibers coexpressing MHC I and IIA is uncertain.

The Mayday distal first metatarsal osteotomy for hallux valgus: a review after the introduction of a new instrument.

We present the short-term follow-up of 55 symptomatic hallux valgus deformities in 38 patients, treated operatively with a modification of the spike distal first metatarsal osteotomy, as described by Gibson and Piggott in 1962. The age range of the patients was 17 to 72 years at the time of surgery. The postoperative follow-up period was 12 to 55 months. Excellent and good clinical and radiographic results were recorded in 96.2% of our patients. Two of the patients (3.8%) were dissatisfied; one of them complained of metatarsalgia after the procedure, and the other had stiffness of the metatarsophalangeal joint and metatarsalgia that had been present before surgery. Three others (5.45%) required revision after early postoperative displacement but were asymptomatic subsequently. We concluded that our technique is an effective method of treating mild hallux valgus deformities with the advantages of simplicity, no shortening of the first metatarsal, and no risk of dorsal tilting of the distal fragment. Hallux valgus (lateral deviation of the great toe) is not a single disorder, as the name implies, but a complex deformity of the first ray that sometimes may involve the lesser toes. More than 130 procedures exist for the surgical correction of hallux valgus, which means that no treatment is unique. No single operation is effective for all bunions. The objectives of surgical treatment are to reduce pain, to restore articular congruency, and to narrow the forefoot without impairing function, by transferring weight to the lesser metatarsals either by shortening or by dorsal tilting of the first metatarsal. Patient selection is important for a satisfactory outcome after surgery of any kind, and our criteria were age, degree of deformity, presence of arthrosis, and subluxation of the first metatarsophalangeal joint. In this study, we present a new method of treating hallux valgus that has been used at Mayday University Hospital since 1990. The technique was first described at the British Orthopaedic Foot Surgery Society, Liverpool, November 1990, and we now present the short-term follow-up results. The procedure is essentially a modification of the spike osteotomy of the neck of the first metatarsal, as described by Gibson and Piggott. It has the advantages of simplicity, no shortening of the first metatarsal, and no risk of dorsal displacement of the distal fragment.