Gender, muscle, and velocity comparisons of mechanomyographic and electromyographic responses during isokinetic muscle actions

The purpose of this study was to examine the responses of peak torque (PT), mean power output (MP), mechanomyographic (MMG) and electromyographic (EMG) amplitude and mean power frequency (MPF) of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) in males and females during maximal, concentric isokinetic muscle actions. Subjects performed maximal leg extensions at 60 degrees s(-1), 120 degrees s(-1), 180 degrees s(-1), 240 degrees s(-1), 300 degrees s(-1), 360 degrees s(-1), 420 degrees s(-1), and 480 degrees s(-1). No gender differences were observed, but there were muscle-specific differences for the patterns of MMG MPF, EMG amplitude, and EMG MPF. The MP and MMG amplitude increased to 180-240 degrees s(-1), plateaued, and then decreased to 480 degrees s(-1). MMG MPF for the VL and VM remained unchanged to 300 degrees s(-1), but then increased to 480 degrees s(-1). The EMG amplitude for the RF and EMG MPF for the VL decreased across velocity. Overall, these findings indicated that there were muscle-specific, velocity-related differences in the associations among motor control strategies (EMG amplitude and MPF) and the mechanical aspects of isokinetic muscular activity (MMG amplitude and MPF).     

Skeletal muscle and hormonal adaptations to circuit weight training in untrained men

Twelve men either performed 10 weeks of timed circuit weight training 3 days week(-1) (CWT; n=8; X+/-SE; age=23.6+/-1.8 years), or were part of a sedentary control group (n=4; age=20.5+/-1.0 years). Significance was P<0.05 for all analyses. The CWT program significantly increased 1 repetition maximum (1 RM) strength for nine of 10 exercises (15-42%). Although no body composition measure significantly changed for the CWT group, low-to-moderate effect sizes were evident for body weight, lean body mass, and relative fat. CWT did not alter percent fiber type, but did increase cross-sectional areas for type IIA fibers (microm(2); pre=5988+/-323, post=7259+/-669). Relative (%) myosin heavy-chain (MHC) expression increased for MHC IIa (pre=42.5+/-2.7, post=50.1+/-2.6), and decreased for MHC IIb (pre=21.8+/-2.8, post=15.4+/-2.4) for the CWT group. Serum testosterone, cortisol, and the testosterone/cortisol ratio did not change at any time for the CWT group. None of the measured variables changed for the control group. These data indicate that for untrained subjects, CWT of the type used resulted in improved muscular strength and a tendency toward increased lean mass. Compared with other types of weight training, fewer adaptations of the muscle fibers were evident. This is likely due in part to the relatively low loads used with this type of resistance exercise.     

Sensitivity of T2-weighted FSE sequences towards physiological iron depositions in normal brains at 1.5 and 3.0 T

To evaluate the sensitivity of T2-weighted fast spin-echo (FSE) sequences to physiological iron depositions in normal brains at MR imaging field strengths of 1.5 and 3.0 T. T2-weighted FSE sequences acquired at 1.5 and 3.0 T clinical imaging systems (Gyroscan Intera, Philips Medical Systems, Best, The Netherlands) were compared by means of MRI in phantoms (n=6) and healthy volunteers (n=10). Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations and of brain areas with physiological iron depositions (nucleus ruber, substantia nigra, globus pallidus) were calculated for either field strength. Apparent susceptibility effects of iron-containing brain structures were qualitatively analyzed by comparing the degree of visible hypointensity by a score system at either field strength. The mean CNR of iron oxide tubes and iron-containing brain areas was significantly decreased at 3.0 T. Qualitative analysis confirmed these measurements. Detection and diagnosis of brain disorders with altered iron content such as neurodegenerative parkinsonian disorders (NPD) or intracerebral hemorrhage should benefit from the increased sensitivity of T2-weighted FSE sequences to susceptibility effects at 3.0 T.     

Local administration of hepatocyte growth factor gene enhances the regeneration of dermis in acute incisional wounds

Hepatocyte growth factor (HGF) has a number of biological activities, e.g., mitogenic, motogenic, antiapoptotic, antifibrous, and morphogenic. It also has angiogenic and angioprotective activities for endothelial cells. The aim of this study was to characterize the role of HGF in wound healing by administering the HGF gene locally to acute incisional skin wounds created on the backs of rats. To create wounds, the backs of Wistar rats were clipped and three 2-cm-long incisional wounds were made deep to the fascia. The wounds contained pannicrus carnosum and were created at intervals of 2 cm. After suturing, the HGF gene was then administered intradermally. Apoptotic cells in wound lesions were identified by TUNEL method as well as by immunological detection of active caspase-3. In the HGF-treated animals, we found almost complete suppression of apoptosis and well-organized wound healing. Histopathological examination revealed that the proliferation of fibroblasts was suppressed and that scar formation was less apparent in the HGF-treated animals compared to the controls. It is thought that administration of the HGF gene immediately after surgery may enhance the healing process through suppressing apoptosis, which occurred in the controls 1 week after suturing the incisional wound. In addition, locally increased HGF expression due to the introduction of the HGF gene to cells around wounds enhances dermal regeneration, possibly by promoting regeneration of dermal tissue, which results in less scarring due to its antifibrotic effect. Thus, HGF supplementation through gene therapy may be an effective strategy for treating wounds, as it increases the regeneration of the dermis to allow for "scarless wound healing."     

Pelvic floor maximal strength using vaginal digital assessment compared to dynamometric measurements

AIM: To compare vaginal digital assessment with dynamometric measurements for determining the maximal strength of the pelvic floor muscles (PFM). MATERIALS AND METHODS: Eighty-nine women aged between 21 and 44 participated in the study. An experienced physiotherapist evaluated the maximal strength of the PFM of these women using the modified Oxford grading system (six categories, range 0-5) and dynamometric measurements. The mean maximal forces obtained for all women with the instrumented speculum for each category of digital assessment were compared using ANOVAs. Spearman's rho coefficients were calculated to assess the correlation between the dynamometric and the digital assessments. RESULTS: According to their symptoms and pad test results, 30 women were continent and 59 had stress urinary incontinence (SUI). Based on dynamometric measurements, important overlaps were observed between each category of digital assessment. The ANOVAs indicated that force values differ across categories (F = 10.08; P < 0.001), although contrast analyses revealed no differences in the mean maximal forces between adjacent digital-assessment categories (1-2, 2-3, 3-4, 4-5). Mean force values differed significantly only between non-adjacent levels in digital assessment, for example, between 1 and 3; 1 and 4; 1 and 5; 2 and 4; 2 and 5 (P < 0.05). Significant correlations were found between the two measurements with coefficients of r = 0.727, r = 0.450, and r = 0.564 for continent, incontinent, and all women, respectively (P < 0.01). CONCLUSIONS: Even if the dynamometric mean forces of the PFM increased across subsequent categories of digital assessment, the force values between two adjacent categories do not differ. This limitation of digital assessment should be considered by clinicians and researchers when choosing treatment orientation and evaluating treatment outcomes.     

Force-length relationship in the pelvic floor muscles under transverse vaginal distension: a method study in healthy women

AIMS: The purpose of this study was to investigate whether there is a relationship between changes in the diameter of the urogenital hiatus and force developed in pelvic floor musculature. In addition, we wanted to examine the reliability of the method that measures force development in the pelvic floor in the transverse direction of the urogenital hiatus. MATERIALS AND METHODS: Passive and total force in the pelvic floor was measured with an intra-vaginal device in 20 healthy parous volunteers. The measurements were done with a consecutively increasing diameter in the transverse plane of the urogenital hiatus. The procedure was repeated with a few days interval. RESULTS: The measurements show an increase in force with an increasing device-diameter. The results are reliable at all the diameters tested, estimated by the within-subject day-to-day variability which was non-significant. The 40 mm diameter device is most favourable, estimated by Bland Altman plots of the test-retest measurements. CONCLUSIONS: Force development in pelvic floor muscles increased as a function of vaginal diameter when measured in the frontal plane. The measurements were reliable at all the different diameters chosen.     

Human parathyroid hormone (1-34) increases mass and structure of the cortical shell,with resultant increase in lumbar bone strength,in ovariectomized rats

Estrogen deficiency causes reduction of bone mass and abnormal bone microarchitecture, consequently reducing bone strength. Human parathyroid hormone (hPTH) (1-34) increases bone mass and strength. To clarify the factors that determine the recovery of bone strength in the lumbar vertebrae of ovariectomized rats by intermittent hPTH administration, we analyzed the relationship between skeletal measurements and bone strength. Human PTH (1-34) administration resulted in recovery of cortical bone mineral content (BMC) and cortical bone area to sham the levels, but in resulted in a less pronounced recovery of trabecular BMC and no increase in the total cross-sectional area of the vertebral body. Of the three-dimensional (3D) trabecular bone parameters, hPTH (1-34) increased trabecular thickness (Tb.Th). The cortical shell area of L4, determined by histomorphometry, was also increased. In hPTH-treated rats, the only determinant of the compressive load of L5 was the cortical shell BMC, in the early recovery period (days 42–84). Our data suggest that increased cortical bone mass contributes more than trabecular bone mass and structure to the recovery of bone strength in response to hPTH therapy in the rat lumbar vertebral body after ovariectomy.     

Burst strength of laparoscopic and open hernia repair

Background: There are few reports of overall strength of laparoscopic and open incisional hernia repair. Methods: After anesthesia, a 2-inch circular defect was made in the abdominal wall of 28 female swine. Gore-Tex DualMesh Biomaterial (W. L. Gore & Associates, Flagstaff, AZ) was used for all repairs. Sixteen animals underwent open repair and 12 underwent laparoscopic repair. Burst strength was detected within 2 weeks and at 6 weeks by euthanizing the animals and insufflating the abdominal cavity with water while measuring the intraabdominal pressure until it could no longer be pressurized. Results: Three events occurred after insufflation: rupture around patch (R), dissection from insufflation or pressure monitoring sites (D), or rectal prolapse (P). Failure after open early repair occurred at 289 (range 219–388) mmHg with 7-R, 1-P and late 289 (196–343) mmHg with 1-R, 6-P. Failure after laparoscopic early repair occurred at 259 (191–388) mmHg with 4-R, 1-P, 1-D and late 291 (140–330) mmHg with 2-R, 1-P, 3-D. Late groups were less likely to rupture. Conclusion: Both hernia repairs are durable at early and late periods. Tissue ingrowth adds to repair strength. We could not show that one repair was stronger than the other. Nonetheless, laparoscopic repair tended to degrade by dissection, which was our highest pressure event.     

Effects of low-power laser irradiation on survival of random skin flap in rats

This research was designed to study the effects of low-power helium–neon (He–Ne) laser irradiation on random skin flap survival in rat. Fifty 50 male rats were randomly divided into five groups. On the dorsum of each rat, one full thickness random skin flap which contained no specific vessel was elevated. Groups 1 to 4 were exposed to different models of a low-power He–Ne laser. Group 5 rats received no laser treatment and were considered as the control group. The energy density of the He–Ne laser used was 0.2 J/cm². Immediately after surgery and at day 7, the surface area of all flaps was determined. Histological and tensiometrical studies on the surviving part of the flaps were also performed. The data obtained were analyzed by ANOVA. The results showed a significant difference in the surface area of survival parts of flaps and density of blood vessels on day 7 between group 3 rats and the other groups (P=0.0188, P=0.0455). Low-power He–Ne laser irradiation of flaps without recognized blood vessels in rats, reduced vasospasm, produced vasodilation, and caused a significant increase in the surviving surface area.Presented at the 14th World Congress of the International Society for Laser Surgery and Medicine, India, 27–30th August, 2001     

Initial experience with a new method for the dynamic assessment of pelvic floor function in women: the Kolpexin Pull Test

The aim of this study was to evaluate a newly developed, simple test for assessing pelvic floor muscular function in women. Pelvic floor strength in women with symptomatic pelvic floor dysfunction was evaluated with a newly developed assessment tool, the Kolpexin Pull Test, and compared to a clinically validated digital pelvic floor strength assessment scale (DPA). A 36-mm Kolpexin sphere was inserted into the vagina above the levator plate and connected to a digital tensiometer/force gauge. The force required to remove the sphere was recorded for three resting trials and three maximum pelvic floor contractions. Results of the DPA and Kolpexin Pull Test were analyzed using ANOVAs of contrast variables, intraclass correlations, and regression analyses. Twenty-one women participated in the study. Age range was 36–85 years, parity range was 2–5. All six trials required less than 5 min to perform in each patient. Intraperson maximum contraction data were correlated at 0.96 (95% CI: 0.91, 0.98), and were greater at higher DPA scores (p=0.016). There were positive correlations between the maximum contraction and DPA data (adjusted R²=0.52; p <0.001), and the maximum contraction minus resting vs DPA data (adjusted R²=0.54; p< 0.001). The Kolpexin Pull Test is reproducible, rapid, and correlates with digital clinical assessment of pelvic floor strength during maximal contractions.Abbreviations DPA Digital pelvic assessment - MC Maximum pelvic floor contraction - RP Relaxed pelvic floor Editorial Comment: This paper is an interesting pilot study of a new technique to measure pelvic muscle strength. Several other techniques have already been described. As the authors have stated, all methods have flaws, including the relatively easy and reproducible digital pelvic assessment (DPA). The Kolpexin sphere offers the hope of more objective testing than the DPA, overcomes the contribution of Valsalva to the pressure perineometry readings, and is easier to perform than ultrasound or EMG. The authors did not fully convince us of the objectivity of the measurements, as the study was not blinded. Also, we do not know whether the size of the sphere altered the readings in women in different heights and/or weights. If, on further testing, this technique is shown to have inter- as well as intraexaminer reproducibility, it may contribute to the evaluation of patients for management as well as for research.