Full suspension mountain bike improves off-road cycling performance

AIM

The purpose of the present study was to determine the effects of suspension systems on the cycling performance of cyclists during off-road bicycling.

METHODS

Eight elite male cyclists (67.8+/-5.8 ml/min/kg of (.-)VO(2max)) performed 30-minute riding tests on bicycles with 2 different suspension setups: front suspension (FS) and front and rear suspension (FRS). Heart rate, blood lactate concentration, pedaling power, cadence, cycling velocity, and completed distance during the trial were measured creatin kinase (CK), lactic dehydrogenase (LDH) and glutamic-oxaloacetic transaminase (GOT) were measured before and after the trials.

RESULTS

The average cadence during the trial was significantly higher (p<0.05) with the FRS (73.6+/-6.1 rpm) than the FS (70.2+/-6.2 rpm). Subjects rode significantly faster (p<0.05) on FRS (24.1+/-2.6 km/h) than FS bikes (22.9+/-2.4 km/h), although no significant difference was observed in pedaling power (240.7+/-26.6 W vs 242.2+/-28.8 W, FS vs FRS, respectively). Serum creatin kinase increased significantly (p<0.05) at 24 h after the trial when cyclists exercised with the FS bike.

CONCLUSIONS

We conclude that the FRS improved cycling performance over rough terrain. FRS might therefore be more suitable for cross-country mountain bike races.

Maintenance of bone mass and mechanical properties after short-term cessation of high impact exercise in rats

Abstract. The effects of cessation of high-impact exercise on bone mass in female Wistar rats was assessed. Fifty 10-week old rats were randomly divided into five groups (n = 10): 4 weeks jump-exercise (4JEX), 4 weeks sedentary control (4S), 8 weeks jump-exercise (8JEX), 4 weeks jump-exercise followed by 4 weeks sedentary (4JEX4S) and 8 weeks sedentary control (8S). The rats were jumped trained 40 times/session, 5 days/week. After 4 weeks or 8 weeks the mass and breaking force in tibia and cross-sectional areas of the tibia were measured. The tibia in the 4JEX and 8JEX groups had significantly greater fat-free dry weight and maximum loads at the fracture tests than those in the 4S and 8S groups. The tibia of 4JEX and 8JEX also had significantly larger cortical area without a significant change in the medullary area at the cross-sectional analysis. Bone mass acquired in 4JEX4S group was retained after cessation of exercise. The results indicate that high-impact jump-exercise, which is osteotropic, leads to an increased cortical bone with enhanced periosteal bone formation, which is also, however, maintained after cessation of exercise. It is therefore suggested that high-impact jump-exercise may provide greater safety margin against disuse-related or/and age-related bone loss and skeletal fragility later in life.

Effect of high-impact and low-repetition training on bones in ovariectomized rats

This study was designed to investigate the effect of high-impact and low-repetition jump training on bones in ovariectomized (OVX) rats. Forty female Wistar rats were sham-operated (sham) or OVX at the age of 11 weeks. The rats were divided randomly into the following four groups: sham-sedentary (SS; n = 10), sham-exercised (SE; n = 10), OVX-sedentary (OS; n = 10), and OVX-exercised (OE; n = 10). The rats started the jump training at the age of 12 weeks. The jump-training protocol was 10 times/day, 5 days/week and the jumping-height was 40 cm. After 8 weeks of training, the mass and breaking force in the tibia and ulna, cross-sectional areas of diaphysis in the tibia, and serum bone turnover markers were measured. The jump training significantly increased the fat-free dry weight, ash weight, and ultimate breaking force in the tibia. The rate of increase in these parameters was similar in both the sham and the OVX groups. On the other hand, in the ulna, there were no significant changes in the ultimate breaking force. The jump training significantly increased the periosteal perimeter and cortical area, although the increase in these parameters in OE compared with OS was lower than that in SE compared with SS. The jump training significantly increased serum osteocalcin in the OVX groups, as well as in the sham groups. These results suggest that high-impact and low-repetition training had beneficial effects on bone formation and bone biomechanical properties in OVX rats, as well as in sham rats.

A basic class I chitinase expression in winged bean is up-regulated by osmotic stress

We isolated a cDNA for basic class I chitinase (ChitiWb1). ChitiWb1 cDNA encodes a protein that consists of 315 amino acid residues and has a signal peptide. Northern blot analysis indicated that the class I chitinase mRNA in leaves and cultured cells of winged bean was increased by treatments with NaCl, KCl, CaCl2, mannitol or saccharose, but not with abscisic acid. Thus, class I chitinase expression was shown to be up-regulated by osmotic stress.

Exercise and mechanical loading increase periosteal bone formation and whole bone strength in C57BL/6J mice but not in C3H/Hej mice

To identify the genes, and the mechanisms that account for the 53% higher peak bone density in C3H/HeJ (C3H) mice compared with C57BL/6J (B6) mice, we are performing quantitative trait locus and phenotypic analyses. The phenotypic studies revealed differences in bone formation and resorption, and showed that hindlimb immobilization (by sciatic neurectomy) caused a greater increase in endosteal resorption in the tibiae of B6 compared with C3H mice. The current studies were intended to examine the hypothesis that the bones of C3H mice are less sensitive to mechanical loading than the bones of B6 mice. To increase mechanical loading, 9-week-old female B6 and C3H mice (n = 10-13 mice/group) were subjected to a jumping exercise (20 jumps/day, 5 days/week, to heights of 20-30 cm) for a total of 4 weeks. Control mice did not jump. Osteocalcin, alkaline phosphatase (ALP) activity, and IGF-I were measured in serum. The left tibiae were used for histomorphometry (ground cross-sections prepared at the tibiofibular junction) and the right tibiae and femora were used for determinations of bone breaking strength (3-point bending). The results of these studies revealed (1) significant effects of both mouse strain (B6 and C3H) and the jumping exercise on tibial strength; (2) an exercise-dependent increase in serum IGF-I in C3H, but not B6 mice; and (3) no effects on serum ALP or osteocalcin. The histomorphometric analyses showed no effect of exercise on C3H tibiae, but significant exercise-dependent increases in total bone area, periosteal perimeter, periosteal mineral apposition rate (MAR), and periosteal bone formation (P < 0.02 for each) in B6 tibiae. There were no effects of exercise on periosteal resorption or any endosteal measurement in either C3H or B6 mice. Since the jumping exercise was designed to cause a two-three fold increase in muscular-skeletal loading at the tibio-fibular junction, and the calculated stress (g/mm2) at this sampling site was only 16% greater for B6 compared with C3H mice, we had anticipated that both strains of mice would show exercise-dependent increases in periosteal bone formation, with a greater response in the B6 mice. The lack of a response in the C3H tibiae demonstrates that the bones of C3H mice are less sensitive to mechanical loading (and unloading) than the bones of B6 mice.

[Primary Sjögren's syndrome presenting as unconsciousness associated with IgA-lambda M-protein]

We describe the case of a 43-year-old woman who presented with primary Sjögren's syndrome (SS) which manifestated as unconsciousness due to M protein. A diagnosis of SS was made based on a ten-year history of dryness, a Shirmer test, and the histological findings of labial biopsy. A rouleaux formation was observed and serum protein electrophoresis revealed a monoclonal spike of 4.0 gm/dl in the gamma-region, which was characterized as IgA-lambda. Biopsy of the minor salivary glands showed marked polyclonal lymphoproliferation with lymphoid follicles, including both T cells and B cells as revealed by immunohistological staining. Therefore, the patient had a lymphoproliferative lesion of the minor salivary glands, which is also known as pseudolymphoma. We conclude that fainting associated with marked M protein may be manifestation of SS. Such cases should be followed carefully since the subsequent neoplastic transformation of pseudolymphomas have been previously reported.

Five jumps per day increase bone mass and breaking force in rats

The effects of jump training on bone morphological and mechanical properties were investigated in immature bones of female Fischer 344 rats. Five-week-old rats were divided into control or five jump-trained groups comprised of 5-, 10-, 20-, 40-, and 100-jump groups, representing the number of jumps per day. The rats were jump-trained 5 days/week for 8 weeks, and the height of jump was increased to 40 cm progressively. The femur and tibia in the 5-jump group had significantly greater fat-free dry weights per body weight and maximum loads at the fracture tests than those in the control group. The tibia in the 5-jump group also had significantly larger cortical area at the cross-sectional analysis. Although a slight tendency toward increase according to the number of jumps per day was observed, there were few differences in bone morphological and mechanical parameters among the 10-, 20-, and 40-jump groups. The present results indicate that a large number of strains per day is not necessary for bone hypertrophy to develop in rats.

Expression of endothelial nitric oxide synthase in human eccrine clear cells

Nitric oxide is generated from L-arginine by nitric oxide synthase (NOS), which has at least three isoforms; endothelial-type NOS (eNOS) and brain-type NOS (bNOS) are constitutive enzymes, and inducible-type NOS (iNOS) is expressed after stimulation. Studies by the avidin-biotin immunocomplex method, revealed eNOS immunoreactivity exclusively in the human eccrine clear cells. No eNOS immunoreactivity was observed in the eccrine dark cells or myoepithelial cells. No staining of iNOS or bNOS was observed in the eccrine gland. These findings indicate that NO plays a physiological part in the production and/or excretion of sweat in the human skin eccrine gland.

Immunohistochemical localization of nitric oxide synthase in normal human skin: expression of endothelial-type and inducible-type nitric oxide synthase in keratinocytes

Nitric oxide (NO) is a critical mediator of various biological functions. NO is generated from L-arginine by nitric oxide synthase (NOS), which has three isoforms; endothelial-type NOS (eNOS) and brain-type NOS (bNOS) are constitutive enzymes, and inducible-type NOS (iNOS) is expressed after stimulation. We investigated the expression of NOS in normal human skin by an immunohistochemical technique and western blotting analysis. In human skin, epidermal keratinocytes and the outer root sheath were labeled with not only eNOS antibody but also with iNOS antibody. Both eNOS and iNOS protein in epidermal keratinocytes were confirmed by western blotting. eNOS immunoreactivity was observed in endothelial cells, fibroblasts, the arrector pili muscle, apocrine secretory gland, eccrine coiled duct, and eccrine secretory gland. bNOS immunoreactivity was observed in mast cells. No staining with anti-bNOS antibody was observed in any other cell type. Our present findings suggest that epidermal keratinocytes in normal human skin contain both eNOS and iNOS.

Effects of jump training on bone hypertrophy in young and old rats

The effects of jump training on bone hypertrophy were investigated in 3, 6, 12, 20 and 27 month-old female Fischer 344 rats. The rats of all age groups were divided into jump training (height: 40 cm, 100 times/day, 5 days/wk for 8 wk), run training (speed: 30 ml/min, 1 h/day, 5 days/wk for 8 wk) or sedentary group. Fat-free dry weights (FFW) of the femur and the tibia were significantly greater in the jump-trained rats than in the run-trained rats, and were significantly greater in the run-trained rats than in the sedentary rats. Jump training significantly increased FFW of the femur and the tibia not only in young rats but also in old rats, while run training did not increase FFW significantly in old rats. In young rats, both jump training and run training significantly increased the length of the femur and the tibia and the diameter of the femur. The diameter of the tibia was greater in the jump-trained rats than in the sedentary and the run-trained rats in all age groups. The results of the present study indicate that jump training was a more effective training mode than run training for bone hypertrophy and that the effects were not limited by age.

[Studies on serum protein fractions of patients with uterine cervical cancer undergoing radiotherapy: relationship between changes in serum protein fractions and prognosis]

The levels of 23 protein components of the sera of 84 patients with uterine cervical cancer undergoing radiotherapy were determined by a single radial immunodiffusion method, before radiation therapy, after whole pelvic irradiation, and after intracavitary irradiation using a remote after roading system (RALS). We examined the correlations between changes in serum protein fractions and the prognosis of the patients. The patients with uterine cervical cancer were treated with combined external irradiation of 60Co gamma-rays or 10 MV X-rays, and RALS therapy. The levels of the same protein components were also measured in 21 normal adult women as a control. All patients were observed between 4 years and 8 years after radiation therapy. In the pretreatment sera obtained from patients with uterine cervical cancer, the concentrations of prealbumin (Prealb), alpha 2HS glycoprotein (alpha 2 HS), alpha 2-plasmin inhibitor (alpha 2PI), transferrin (Tf), plasminogen (Pmg), albumin (Alb), IgM and hemopexin (Hx) were significantly lower than those normal controls. However the serum concentrations of: alpha 1-antichymotrypsin (alpha 1 X), haptoglobin (Hp), C9, fibrinogen (Fib), ceruloplasmin (Cp), alpha 1-acid glycoprotein (alpha 1AG), alpha 1-antitrypsin (alpha 1AT) and C4 were elevated. At the completion of whole pelvic irradiation and RALS therapy, the Hp, C4, and Fib levels were significantly lower than those before radiation therapy, whereas Prealb, alpha 2HS and alpha 2PI were elevated. In patients who had lived between 4 years and 8 years after radiation therapy, the Cp, alpha 1 AG, Hp and C9 levels measured before radiation therapy were reduced significantly, while Tf was elevated compared with patients who died within 4 years. In those who had lived more than 4 years, the alpha 1 AT, Hp, alpha 1X, Cp and C9 levels measured after whole pelvic irradiation were reduced significantly; while the C4 level was elevated. In cases of uterine cervical cancer followed for a period of 4 to 8 years after radiation therapy, multiple regression analysis was used to determine whether increased concentrations of serum protein fractions were associated with good prognosis for the original disease. Tf, Pmg, and alpha 1AT before radiation therapy were positively correlated with survival, whereas AT III, Cp, C1Inh, IgA, alpha 1 AG and C9 showed negative correlations. After whole pelvic irradiation,Pmg, C4 Prealb, Alb,alpha 2M and Hp were found to be positively associated with survival, whereas Tf, alpha 2PI, AT III, alpha 1 AT,C1Inh, C9 and IgA were negative factors.

CT and MRI manifestations of intraabdominal panniculitis

We report a case of intraabdominal panniculitis. Computed tomography (CT) showed diffuse increased attenuation in the omentum, mesentery, and retroperitoneal region. As the disease progressed, the entire mesentery and retroperitoneal regions were involved. On magnetic resonance imaging (MRI), the lesion demonstrated an intermediate signal intensity on T1-weighted images and a slightly high signal intensity on T2-weighted images. Though the radiologic findings are not specific, this condition should be considered in the appropriate clinical context.

Immunocytochemical localization of copper-zinc superoxide dismutase in mouse olfactory mucosa

Copper-zinc superoxide dismutase (Cu-Zn SOD) has been localized in mouse nasal mucosa. Immunocytochemical staining using polyclonal antibody against Cu-Zn SOD revealed endogenous Cu-Zn SOD in sustentacular cells in the olfactory area, and in ciliated epithelial cells in the respiratory area of the olfactory mucosa. Since these cells are located in the superficial portion of the olfactory mucosa, Cu-Zn SOD may serve as an intracellular antioxidant.

Effects of voluntary exercise on bone growth and calcium metabolism in spontaneously hypertensive rats

The effects of voluntary exercise on bone length and calcium metabolism were investigated in spontaneously hypertensive rats (SHR) and Wistar rats. They were classified into voluntary exercise or sedentary group. Systolic blood pressure (SBP), bone length, urinary calcium excretion, plasma calcium and parathyroid hormone levels (PTH) were measured for analysis. SBP of the trained SHR (T-SHR) was significantly lower than that of the nontrained SHR (NT-SHR) at 10 and 11 weeks of age, but the trained Wistar rats (T-WR) and the nontrained Wistar rats (NT-WR) had similar SBP throughout the experimental period. The T-SHR had significantly longer bones in the extremities and the trunk than the NT-SHR, whereas the T-WR had similar or shorter bones than the NT-WR. The PTH level at 12 weeks of age was significantly lower in the T-SHR than in the NT-SHR. The urinary calcium excretion of the T-SHR was greater than that of the NT-SHR, but the food intake (calcium intake) of the T-SHR was also greater. The urinary calcium excretion and food intake of the T-WR and NT-WR were similar. No noticeable differences were observed in the plasma calcium level between the T-SHR and NT-SHR, the T-WR and NT-WR. From these results it is suggested that the abnormal calcium metabolism in the SHR is improved in some degree by voluntary exercise.

Finite element model of facial soft tissue. Deformation following surgical correction

The finite element method is used to predict facial deformation following orthognathic surgery for mandibular prognathism. The deformation is calculated using a model that assumes severe skeletal class III malocclusion. The possibilities and limitations of this method for clinical application are described.

The inheritance of β-amylase null in storage roots of sweet potato,Ipomoea batatas (L.) Lam

Several sweet potato genotypes were found to lack completely or to have only traces ofβ-amylase in their storage roots. Such genotypes do not increase in sweetness during cooking because, without a sufficient amount ofβ-amylase, the normal hydrolysis of starch to maltose does not occur in the cooking process. In order to study the inheritance of this biochemical variant in the genotype, 41 families were generated. The following conclusions were drawn from analyzing these families. (1) This trait is controlled by one recessive allele (designatedβ-amy) (2) It is inherited in a hexasomic or tetradisomic manner, but not disomically or tetrasomically. This conclusion supports previous cytological data that sweet potato is an autohexaploid or has two identical genomes plus one genome which is somewhat different. (3) Theβ-amy allele appears to exist at a high frequency in cultivated germplasm. (4) Breeding sweet potato for lowβ-amylase activity is relatively easy. New types of sweet potato without normalβ-amylase activity have great potential for processing and as a staple food.

[A case of the benign adrenal adenoma with remarkably high concentrations of deoxycorticosterone and 11-deoxycortisol]

The case was a 33-year-old woman with hypertension and hypokalemia, who presented depression of renin activity and the abnormal elevation of plasma deoxycorticosterone (DOC) and 11-deoxycortisol on laboratory tests. After admission, abdominal CT scan, 131I-adosterol scintigram and adrenal venogram revealed a tumor in the left adrenal, which histologically seemed to be benign. When the tumor was resected, blood pressure and all the biochemical data returned to normal range. DOC and 11-deoxycortisol levels in the tumor were abnormally elevated as compared with those in the normal adrenal tissue. These findings suggested that the abnormal elevation of hormone levels resulted from depression of 11 beta-hydroxylase. Though numerous adrenal tumors have been documented, we rarely encounter an apparently benign adrenal tumor that produces 2 kinds of hormones. This seemed to be the first case of benign adrenal tumor in which both DOC and 11-deoxycortisol were elevated.

Effect of albumin coating on the in vitro blood compatibility of Dacron arterial prostheses

A recirculating in vitro perfusion system was used to assess the effect of albumin precoating on the thrombogenicity of Dacron vascular grafts. A complete analysis of platelet activation was carried out, involving platelet count, release, adhesion and aggregation. Fibrin formation was assessed by measuring fibrinogen levels and fibrinopeptide A production; leucocyte interaction was analysed by measuring total leucocyte count as well as an analysis of cell adhesion to the surface by scanning electron microscopy. The platelet count decreased progressively with perfusion time for Dacron until by 30 min, it had declined to 69% +/- 2% of baseline. The platelet count did not, however, change significantly from baseline when albumin-coated Dacron was tested. Release of platelet factor 4 and beta-thromboglobulin at 180 min for Dacron was 37.8 +/- 29.8 times and 66.9 +/- 18.2 times baseline, respectively, while albumin coating caused significantly less (P less than 0.03) platelet release. Albumin coating diminished coagulation activation and fibrinopeptide A formation. The total leucocyte concentration decreased significantly for Dacron by 180 min, while that for albumin-coated Dacron did not change significantly from baseline levels. Albumin coating produced a film-like covering over the Dacron. For Dacron, there were numerous leucocytes and platelets adherent to the surface, whilst cellular deposition was minimal upon the albumin-coated surface. Thus, albumin coating improved the short-term blood compatibility of Dacron by all of the methods employed in this study.

Human platelet interactions with surfaces of type I collagen, chondroitin-4-sulphate, and chondroitin-6-sulphate in vitro

In vitro human platelet interactions with surfaces of type I collagen, chondroitin-6-sulphate (CH-6-S), chondroitin-4-sulphate (CH-4-S), a CH-6-S/collagen layer, and a collagen-CH-6-S complex were investigated. Polystyrene and silanized glass served as controls. Platelet counts, platelet factor 4 released, and platelet aggregating ability for the different surfaces were compared with controls. Platelet count and platelet factor 4 release data showed that there were no differences between surfaces of CH-6-S, CH-4-S and the controls. However, significant differences in platelet counts and platelet factor 4 released were found when collagen, the CH-6-S/collagen layer, and the collagen-CH-6-S complex were compared with controls. The pure type I collagen surface had the greatest influence on platelet activation. The collagen-CH-6-S complex had a greater effect that the CH-6-S/collagen layer on platelet activation. It appears that chondroitin-6-sulphate can modify the platelet activity of type I collagen.

Correlation between low gastric pH and the formation of gizzard erosions in chicks

1. The inner lining of the gizzard was degraded by in vitro pepsin treatment at pH values lower than 2. 2. A significant linear regression was observed between the pH values on the surface of the inner lining and those on the gizzard mucous layer just under the lining. 3. The control chicks had a specific distribution pattern of pH values on the lining of the gizzard. By feeding a gizzard erosion inducer, pH values were lowered and the distribution pattern disappeared. In the latter case, however, a gastric erosion was observed consistently at the area which showed the lowest pH value in the control chicks. 4. From the results, possible mechanisms of the formation of gizzard erosions are discussed.