Capillary Architecture in the Skeletal Muscles in the Rat Hind Limb

We observed differences in the capillary architecture of the skeletal muscles that have different fiber metabolism. The soleus, the vastus intermedius and the tibialis anterior muscles of adult Wistar rats were prepared using two different techniques. Samples for adenosine triphosphatase (ATPase) staining were prepared following Dubovitz's method, and the distributions of fiber type, Types 1, 2A and 2B, were analyzed. Then, corrosion casts of capillary architecture of these muscles prepared following Murakami's method were observed with a scanning electron microscope (SEM) and compared with the fiber distribution. The fiber type composition of the soleus muscle showed Type 1 (slow-twitch) dominance and that of the vastus intermedius and the tibialis anterior muscle showed Type 2 (fast-twitch) dominance. The capillaries of the soleus muscle were tortuous, and this was thought to be advantageous for blood supply. In contrast, the capillaries of the vastus intermedius and tibialis anterior muscles had a relatively parallel pattern. Additionally, two different patterns of capillary architecture that appeared to correspond to certain metabolic characteristic of different muscle fiber types were preserved with corrosion casting. In conclusion, comparative studies on capillary architecture of the skeletal muscles are useful for analyses of its function. </p

Patient survival after total knee arthroplasty.

The authors analyzed the 5-year and 9-year survival in 134 of 165 patients who underwent total knee arthroplasties from 1989 to 1996 in our department. Patients were followed until December 31, 1998, or until the time of death. Diagnoses were rheumatoid arthritis in 81 patients (132 knees) and osteoarthritis in 53 patients (79 knees). The survival of the patients was compared to that of the age- and sex-adjusted general population. Kaplan-Meier survival curves were constructed. Twenty-two patients in the study died before the end of the follow-up. The cumulative 5-year patient survival was 88.7%, and 9-year patient survival was 64.4% for total knee arthroplasty patients. The standardized mortality ratio was 0.11 (95% confidence interval: 0.02-0.40) for the patients with osteoarthritis, and 0.81 (95% confidence interval: 0.52-1.25) for the patients with rheumatoid arthritis. The Cox proportional hazards model showed that the factors of male sex and rheumatoid arthritis were related to a higher mortality rate in the total knee arthroplasty group.</p

Evaluation of the thigh muscles after knee exercise on a Cybex II.

We investigated the degree of local heat and swelling of the thigh muscles produced by exercise. Eleven university athletes aged from 19 to 23 years old performed isokinetic exercise of the right knee on a Cybex II. Then serial determination of thigh circumference and thigh temperature (up to 120 min after exercise) as well as serial magnetic resonance (MR) imaging (up to 60 min after exercise) was performed on both thighs. The circumference of the right thigh peaked at 5.6 +/- 2.1 min after exercise and returned to normal at 38.6 +/- 9.2 min. The temperature of the right thigh peaked at 14.2 +/- 5.7 min after exercise and was not normalized after 120 min except in two subjects. T2-weighted MR images showed a marked increase in the signal intensity of the right knee flexor and extensor muscles. The signal intensity peaked immediately after exercise and subsequently decreased gradually but did not return to normal after 60 min in some muscles. Changes in the thigh circumference were closely correlated with changes in the MR findings. The changes in the thigh muscles after knee exercise could be demonstrated using MR imaging, thigh circumference, and thigh temperature data. These parameters may provide indicators for managing muscle fatigue and recovery.</p

Influence of exercise on muscle fibers in rats with steroid myopathy.

The influence of mild exercise on skeletal muscle fibers was investigated histochemically to assess the effects of exercise on steroid myopathy and its efficacy for preventing this disease. Twenty male Wistar rats were divided into 4 groups of 5 each: group T, which received exercise alone; group S which received steroid alone; group ST which received both exercise and steroid; and group C, the control group. In groups S and ST, hydrocortisone was administered subcutaneously at a dose of 10 mg/kg/day for 4 weeks. In the exercise groups, the animals were made to run at a speed of 15 m/min for about 1 h/day for 5 days a week on a treadmill. After the completion of treadmill exercise and steroid administration for 4 weeks, the rats were anesthetized with Nembutal, the soleus muscle (SOL) and the extensor digitorum longus muscle (EDL) were removed and prepared for examinations. The area of type I fibers in the SOL was significantly larger in group ST than in group S. The area of type IIa fibers in the EDL was significantly larger in group ST than in group S. In group S, the proportion of type I fibers in the SOL was significantly lower than in the other three groups. There was little difference in fiber type distribution between groups ST and C. These results suggest that steroid myopathy can be prevented by even mild exercise.</p

The CD8+ Dendritic Cell Subset Selectively Endocytoses Dying Cells in Culture and In Vivo

Dendritic cells (DCs) are able in tissue culture to phagocytose and present antigens derived from infected, malignant, and allogeneic cells. Here we show directly that DCs in situ take up these types of cells after fluorescent labeling with carboxyfluorescein succinimidyl ester (CFSE) and injection into mice. The injected cells include syngeneic splenocytes and tumor cell lines, induced to undergo apoptosis ex vivo by exposure to osmotic shock, and allogeneic B cells killed by NK cells in situ. The CFSE-labeled cells in each case are actively endocytosed by DCs in vivo, but only the CD8+ subset. After uptake, all of the phagocytic CD8+ DCs can form major histocompatibility complex class II–peptide complexes, as detected with a monoclonal antibody specific for these complexes. The CD8+ DCs also selectively present cell-associated antigens to both CD4+ and CD8+ T cells. Similar events take place with cultured DCs; CD8+ DCs again selectively take up and present dying cells. In contrast, both CD8+ and CD8− DCs phagocytose latex particles in culture, and both DC subsets present soluble ovalbumin captured in vivo. Therefore CD8+ DCs are specialized to capture dying cells, and this helps to explain their selective ability to cross present cellular antigens to both CD4+ and CD8+ T cells

IL-7 promotes long-term in vitro survival of unique long-lived memory subset generated from mucosal effector memory CD4(+) T cells in chronic colitis mice

Colitogenic memory CD4(+) T cells are important in the pathogenesis of inflammatory bowel disease (IBD). Although memory stem cells with high survival and self-renewal capacity were recently identified in both mice and humans, it is unclear whether a similar subset is present in chronic colitis mice. We sought to identify and purify a long-lived subset of colitogenic memory CD4(+) T cells, which may be targets for treatment of IBD. A long-lived subset of colitogenic memory CD4(+) T cells was purified using a long-term culture system. The characteristics of these cells were assessed. Interleukin (IL)-7 promoted the in vitro survival for >8 weeks of lamina propria (LP) CD4(+) T cells from colitic SOD mice previously injected with CD4(+)CD45RB(high) T cells. These cells were in a quiescent state and divided a maximum of 5 times in 4 weeks. LP CD4(+) T cells expressed higher levels of Bcl-2, integrin-alpha 4 beta 7, CXCR3 and CD25 after than before culture, as well as secreting high concentrations of IL-2 and low concentrations of IFN-gamma and IL-17 in response to intestinal bacterial antigens. LP CD4(+) T cells from colitic mice cultured with IL-7 for 8 weeks induced more severe colitis than LP CD4(+) T cells cultured for 4 weeks. We developed a novel culture system to purify a long-lived, highly pathogenic memory subset from activated LP CD4(+) T cells. IL-7 promoted long-term in vitro survival of this subset in a quiescent state. This subset will be a novel, effective target for the treatment of IBD

The novel latex agglutination turbidimetric immunoassay system for simultaneous measurements of calprotectin and hemoglobin in feces

Background/Aims Fecal calprotectin (Fcal) as well as the fecal immunochemical test (FIT) are useful biomarkers for detecting activity and mucosal healing in inflammatory bowel diseases. Here, we report the performance of simultaneous measurements of Fcal and FIT for ulcerative colitis (UC) patients using the newly-developed latex agglutination turbidimetric immunoassay (LATIA) system. Methods Fcal and hemoglobin were measured by the LATIA system in 152 UC patients who underwent colonoscopy. Fcal was also quantified with a conventional enzyme-linked immunosorbent assay (ELISA). Fecal markers were evaluated in conjunction with the mucosal status of UC, which was assessed via the Mayo endoscopic subscore (MES) classification. Results The LATIA system could quantify calprotectin and hemoglobin simultaneously with the same fecal samples within 10 minutes. The values of the Fcal-LATIA closely correlated with those of the Fcal-ELISA (Spearman rank correlation coefficient, r=0.84; P Conclusions The performance of the novel Fcal-LATIA was equivalent to that of the conventional Fcal assay. Simultaneous measurements with FITs would promote the clinical relevance of fecal biomarkers in UC

Measurement of fatigue in knee flexor and extensor muscles.

In order to examine fatigue of the knee flexor and extensor muscles and to investigate the characteristics of muscular fatigue in different sports, a Cybex machine was used to measure muscle fatigue and recovery during isokinetic knee flexion and extension. Eighteen baseball players, 12 soccer players and 13 marathon runners were studied. Each subject was tested in the sitting position and made to perform 50 consecutive right knee bends and stretches at maximum strength. This was done 3 times with an interval of 10 min between each series. The peak torque to body weight ratio and the fatigue rate were determined in each case. In all subjects, the peak torque to body weight ratio was higher for extensors than flexors. Over the 3 trials, the fatigue rate of extensors showed little change, while that of flexors had a tendency to increase. In each subject, knee extensors showed a high fatigue rate but a quick recovery, while knee flexors showed a low fatigue rate but a slow recovery. As the marathon runners had the smallest fatigue rates for both flexors and extensors, we concluded that marathon runners had more stamina than baseball players and soccer players.</p

Measurement of the muscle power of the toes in female marathon runners using a toe dynamometer.

The aim of this study was to investigate the relationship between the strength of the foot muscles that control the toes and disorders such as shin splint. In order to this, we designed and built a toe dynamometer to compare the muscle power exerted through the toes in top female marathon runners and age-matched women not involved in sports. The subjects were 12 top-level female marathon runners (Group A) and 37 student nurses who were not involved in sports (Group B). We devised a dynamometer to measure the total power exerted by the flexor muscles of the 5 toes of a single foot (total flexor power) and the combined power of the abductors of the big (1st) and little (5th) toes (abductor power). In Group A, the total flexor power was 14.3 +/- 5.3 kg in the right foot and 15.4 +/- 4.7 kg in the left foot. The abductor power was 1.9 +/- 1.8 kg in the right foot and 2.2 +/- 1.9 kg in the left foot. In Group B, total flexor power was 18.3 +/- 6.7 kg in the right foot, while the abductor power was 1.9 +/- 1.7 kg. The subjects from Group A with an arch index &#60; 1.0 (n = 8) or &#62; 1.0 (n = 4) were respectively classified as Group I and Group II. In Group I, total flexor power was 14.9 +/- 5.3 kg (right) and 15.5 +/- 5.2 kg (left), while the abductor power was 2.6 +/- 1.9 kg (right), and 3.1 +/- 1.7 kg (left). In Group II, the total flexor power was 13.2 +/- 5.8 kg (right) and 15.1 +/- 4.2 kg (left), while the abductor power was 0.7 +/- 0.6 kg (right) and 0.3 +/- 0.2 kg (left). The abductor power of toes was significantly lower in Group II than in Group I. The incidence of posteromedial shin pain was higher in Group II (75.0%) than in Group I (12.5%).</p

Time to Bone Union after Hybrid Closed-Wedge High Tibial Osteotomy

Medial open- and lateral closed-wedge high tibial osteotomy (hybrid CWHTO) can overcome the limitations of conventional CWHTO and open-wedge HTO (OWHTO) for medial compartmental osteoarthritis (OA) of the knee. Hybrid CWHTO increases stability by using a rigid locking plate and allows early full weight-bearing. However, the literature contains no information about time to bone union after this new procedure. The aim of this study is to evaluate the time to bone union after hybrid CWHTO. We reviewed 44 knees treated with hybrid CWHTO. Patients were able to stand on both legs on the day after surgery and walked with full weight-bearing within 4 weeks of the procedure. The time to achievement of bone union at the osteotomy site was defined as the number of months until bone union was confirmed on radiographic imaging. The mean time to radiographic confirmation of bone union was 4.5±1.5 months after surgery. Eleven knees (25.0%) required 6 months or more. Radiographic analysis and JOA score improved significantly between before and 1 year after surgery (p<0.01). Hybrid CWHTO is a very useful method for treating medial OA, but radiographic bone union requires 4.5 months on average. We must be aware of bone union after hybrid CWHTO