Biomedical subjects
Publications and source records attributed to H Sekiya.
We present a case of recurrent saddle embolism 6 days and 9 days following corrective osteotomy of the left femur in a 64-year-old man with a history of atrial fibrillation. Although saddle embolism is a relatively rare event, orthopaedic surgeons should be aware of this condition.
We present a case of tarsal tunnel syndrome caused by an amyloidoma arising from the talocalcaneal joint in a 64-year-old man with a long history of haemodialysis. He presented with numbness in the medial plantar area of the right foot without any antecedent trauma. The numbness was minimal at rest but gradually worsened, causing difficulty, when walking. Paraesthesia was present on the medial sole of the right foot. A positive Tinel-like sign was noted 2.5 cm below the medial malleolus. Magnetic resonance imaging demonstrated a round lesion, 1 cm in diameter, in the calcaneus, which was hypointense on T1-weighted images and hyperintense on T2-weighted images. In addition, a mass, 1 cm in diameter with a signal isointense to that of muscle was found adjacent to the talocalcaneal joint. The medial plantar nerve was decompressed after removing a solid, 1-cm diameter mass from the talocalcaneal joint. At 6 months post surgery, the numbness had completely resolved. No recurrence was observed at the 24-month follow-up.
During various knee operations, the changes caused by the surgical invasion to the infrapatellar fat pad (IPF) is still unknown. If any changes exist, it will have great influence especially on growing generations. Eighty-four Japanese white rabbits (6-month-old) were divided into three groups: the resection group involving resection of the IPF, the graft group involving resection and reimplantation of the IPF, and the no-surgery group. All these surgical procedures were done in right knees. In all left knees, only arthrotomy was performed, serving as the sham side. After 3, 6, 12, and 24 weeks of the operation, the rabbits were killed. Lengths of the patellar tendon and patellar were measured in lateral X-ray. In order to eliminate individual differences in the patellar height, we defined a new index as percent patellar height (PPH) which indicated the percentage of the patellar height of surgery side compared with that of the sham side. The PPH was 90.6% (3 weeks), 83.0% (6 weeks), 73.6% (12 weeks), and 74.7% (24 weeks) in the resection group, while it was 88.4% (6 weeks), and 88.9% (24 weeks) in the graft group. Postsurgical scar tissue formation occurring where the IPF was removed prevented the normal growth of the patellar tendon. Reimplantation of the IPF lessened the adhesion of the patellar tendon to the surrounding tissue, and better growth of the tendon. These results showed that preservation of the IPF in young individuals could be crucial for the normal growth of the patellar tendon, and critical as well for the prevention of the degeneration of the articular surface.
The authors investigated whether the knowledge of results (KR) schedule influences the extent to which intrinsic feedback is noticed and used. Fifty-six participants received KR that was either delayed over 2 trials (Delay-2) or provided directly after each trial (Delay-0) during 160 trials of an unfamiliar aiming task. No-KR retention tests were given after 80 trials and 1 min and 24 hr after the end of acquisition. After retention, all participants were questioned about their use of intrinsic feedback during practice and whether those sources changed as a function of practice. The Delay-2 group performed significantly less accurately on the 1st and last blocks of acquisition trials but showed a significantly smaller performance decline from acquisition to retention. Moreover, the Delay-2 group noticed and used a greater variety of intrinsic feedback sources and its members were more likely to report that their usage changed with practice.
Treatment once extension contracture of the knee has completed is difficult and costly. The most effective treatment might be the prevention of contracture, especially after joint injury. In order to establish an effective method for contracture prevention we first made an extension contracture in rabbit knees, then studied the effect of a sheet made from hyaluronic acid and carboxymethyl cellulose (HA/CMC) for the prevention of knee contracture. One hundred and twenty two mature male Japanese white rabbits were divided into three groups: (1) group B (n=42), where bony holes were made at the medial and lateral epicondyles, (2) group H (n=40), where HA/CMC sheets were placed on the bony holes, and (3) group S (n=40),where only arthrotomy was performed. All surgical procedures were performed on the right knees. All right knees were fixed at 45 degrees using external fixators; this is the maximum extension angle the rabbit is able to tolerate and still walk. At 1, 3, and 6 weeks after surgery, we measured the moment necessary to flex the knee using a special device. We defined the moment as flexion moment (FM). Forty four left knees were also tested as group N, not operated on and serving as the healthy side. In all groups, FM was increased parallel to the increment of flexion angle from 45 degrees to 115 degrees . At many flexion angles, the FM in group B was higher than those of group S at 3 and 6 weeks. The FM in group H was significantly lower than those of group B at 85 degrees and 95 degrees of flexion at 6 weeks after the operation. By macroscopic observation, the area and degree of adhesion were greater in group B than those of group S. In group H, adhesions around the bony hole were less evident than in group B at 6 weeks after the operation. By histological examination, dense granulation tissue was found adjacent to the bony hole in group B at 3 and 6 weeks after the operation. In contrast, in group H the amount of granulation tissue was smaller at 3 and 6 weeks after the operation than those of group B. The usage of HA/CMC sheet should be effective for prevention of contracture occurring after trauma such as treatment for intra-articular fracture.
We studied carpal tunnel pressure and outcome of endoscopic carpal tunnel release in 42 patients (53 hands) with carpal tunnel syndrome (CTS) and receiving long-term hemodialysis. We compared these results with those of 41 patients (49 hands) with idiopathic CTS. Pressure was measured peroperatively: first, before dilation of the carpal tunnel; second, after dilation but before release of the transverse carpal ligament; and third, after completion of the release. In patients receiving long-term hemodialysis, the highest pressures were 76.9, 56.0, and 7.8 mmHg respectively. In patients with idiopathic CTS, pressures were 68.8, 44.1, and 4.0 mmHg respectively. The clinical outcome was inferior in patients receiving long-term hemodialysis.
Forty participants (age range = 18-35 years) practiced 1 of 2 versions of an aiming task (with or without spring resistance). Knowledge of results (KR) was provided to them either immediately or after a delay of 2 trials. Immediate KR led to significantly more accurate performance during the 80 trials in acquisition but significantly less accurate performance on a 40-trial retention test given 24 hr after practice. In addition, the spring version of the task was performed significantly less accurately than the no-spring version on the 24-hr retention test. Most important, a significant interaction on the 24-hr retention test revealed that performance of the no-spring version of the task, when KR had been given after a 2-trial delay, was significantly more accurate than performance of the other 3 combinations of task version and KR schedule. The results suggest that KR dependency in motor skill learning is related to familiarity with task-intrinsic feedback in addition to the schedule on which KR is presented.
The aim of this study is to characterize the response of alveolar osteocytes to stretching and parathyroid hormone, (1-34) PTH. Osteocytes from primary human alveolar bone were used in the study. Compared to osteoblasts, osteocytes were observed to express lower levels of alkaline phosphatase mRNA and higher levels of osteocalcin mRNA. We found that the effect of PTH and stretching on osteocalcin expression is synergistic. The upregulated steady-state level of osteocalcin mRNA is further upregulated in the presence of PTH (at 1 h after the initiation of stretching). On the other hand, the downregulated level of the message is further downregulated in the presence of PTH (at 3 h after the 3-h stretching). The synergy can be either way, positive or negative, in the course of the response. From this, we presume that related mechanisms are at work between the PTH signaling pathways and the mechanotransduction pathways activated by stretching.
OBJECTIVE: To elucidate the precise immunological features in primary biliary cirrhosis (PBC), we examined the relative prevalence of CD4+ T cells in either symptomatic PBC (sPBC) or asymptomatic PBC patients (aPBC), and furthermore, these results were compared with their histological features. METHODS: Cytokine synthesis of peripheral blood mononuclear cells obtained from 24 PBC patients (9 sPBC and 15 aPBC) were examined by intracellular staining method. The relative prevalence of three distinct CD4+ T cells, gamma-interferon (IFN-gamma)-producing cells (Th1), interleukin-4 (IL-4)-producing cells (Th2), and the cells producing both IL-4 and IFN-gamma (Th0), was analyzed by FACScan and compared with those of closely age-matched healthy and disease controls. RESULTS: The results demonstrated that although a significant difference was not observed in the prevalence of Th1 or Th0, a remarkable difference was observed in the prevalence of Th2 (1.2+/-0.7 in sPBC, 4.1+/-1.3 in healthy subjects, 4.1+/-2.1 in aPBC, 3.4+/-1.3 in chronic hepatitis C, and 3.6+/-2.3 in cirrhosis secondary to CH-C; p < 0.05 for sPBC vs all others). Histological examination of these patients showed that all aPBC patients belonged to relatively early stage (stage I-II) and 7 of 8 sPBC patients belonged to late stage (stage III-IV). Thus, our results suggest that, mainly as a result of the decline of Th2, a predominance of Th1 may exist in advanced stage PBC. CONCLUSIONS: The present results demonstrated that a slight elevation of Th1 prevalence, as well as a significant decline of Th2 prevalence, was observed in peripheral blood of advanced stage PBC.
Patients with Cornelia de Lange syndrome have many anomalies including micrognathia with a small mouth, a high arched palate, and a short neck, which might make laryngoscopy for tracheal intubation difficult during induction of general anesthesia. General anesthesia was performed in a patient with Cornelia de Lange syndrome, and restricted opening of the mouth, which had not been reported previously, was found during laryngoscopy. The possible causes were thought to be temporo-mandibular joint disorders, contracture of the masseter muscle due to injury by self-destructive tendencies, or elogated coronoid process. The potential difficulty with laryngoscopy should be considered for tracheal intubation in a patient with Cornelia de Lange syndrome.
This study extended previous work (Sekiya, Magill, Sidaway, & Anderson, 1994) by examining whether the contextual interference (CI) effect could be found when task variations were controlled by the same generalized motor program (GMP) but differentiated on the basis of overall force parameter modifications. A subsidiary aim of this study was to determine how the amount of practice influenced the CI effect. During 2 acquisition sessions and 2 retention sessions, participants (N = 24) performed 3 task variations in either a blocked (low CI) or serial (high CI) condition. The task variations shared the same relative force structures but differed in the amount of overall force that had to be produced. Analysis of a general error measure revealed a strong CI effect, indicating that overall force parameter modifications of the same GMP created the CI effect. Analyses of various dependent measures, which dissociated GMP from parameter components with regard to force characteristics, revealed that parameter learning, but not GMP learning, was enhanced by high CI practice. No CI effect occurred in any aspect of timing characteristics. The amount of practice used in the present study did not influence the efficacy of the CI effect.
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The motoneurons innervating the musculus levator palpebrae superioris (LPS) of the monkey, the cat and the rabbit were studied using horseradish peroxidase (HRP). Furthermore, LPS motoneurons of the cat and rabbit were studied by the double-labeling method using two fluorescent dyes as retrograde neuronal tracers. After injection of HRP into the right LPS of the monkey and the cat, HRP-labeled neurons were found only in the central caudal nucleus with contralateral preponderance. In contrast, after HRP injection into the right LPS of the rabbit, HRP-labeled neurons were found only in the contralateral oculomotor nucleus. In the double-labeling study, after injection of fast blue (FB) into the right LPS and diamidino yellow dihydrochloride (DY) into the left LPS of the cat and the rabbit, no double-labeled neurons were noted in the central caudal nucleus of the cat nor in the oculomotor nucleus of the rabbit, although double-labeled neurons were identified in the central caudal nucleus of the monkey in our previous study. Cross-innervation was confirmed in the mammals lower than the monkey.
Hypervariable region I (HVRI) of the putative second envelope glycoprotein (gp70) of hepatitis C virus (HCV) undergoes sequential alterations at intervals of several months during the chronic phase of hepatitis. To evaluate the implications of sequence variability in HVRI of HCV, we investigated the sequence variability of the whole envelope-protein(gp35 and gp70)-coding regions of HCV genome derived from patient M in acute and relapsed phases (8-month interval) of hepatitis. From this analysis, we found that a Leu (position 405) in HVRI substituted to Pro, and that 4 additional substitutions could be detected in gp70 during the relapsed phase. Sequence-specific antibody against HVRI derived from patient M was first detected in the serum at 8 months after the onset of hepatitis, but no other specific antibodies against peptides containing amino-acid position(s) substituted in regions other than HVRI could be detected. Epitope mapping using the sequence of HVRI derived from the acute phase of hepatitis was also performed, and a B-cell epitope (positions 397 to 407) of 11 amino acids was identified. However, the Pro variant at position 405 did not display an escape pattern from the antibody produced at 8 months after the onset. In addition, we demonstrated the existence of important amino-acid residue positions which are recognized by the anti-HVRI antibody produced in patient M using introduction point mutations within HVRI.
Hepatitis C virus (HCV) genome shows extensive sequence diversity at 2 hypervariable regions (HVR1 and HVR2) of the putative envelope glycoprotein (gp70). We recently reported that the amino-acid sequence of HVR1, but not of HVR2, underwent a striking mutation or mutated sequentially over a period of several months in patients with chronic hepatitis (CH). Here, we examined whether these genetic alterations in HVR1 occurred in an asymptomatic HCV carrier. The level of HCV RNA in serum was almost the same throughout the 4 time points sampled over 16 months. However, we found that the amino-acid sequence of the HCV HVR1 from this asymptomatic carrier altered with time, as seen in patients with CH. Alterations of amino acids in the HVR1 were correlated with persistent HCV infection rather than with clinical symptoms. Sequence heterogeneity of HVR1 was not correlated with alanine aminotransferase (ALT) values or liver histological findings. The necessity of clinical follow-up of HCV asymptomatic carriers is discussed.
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Magill and Hall (1990) hypothesized that the contextual interference (CI) effect is found only when task variations to be learned are governed by different generalized motor programs (GMPs). The present experiments examined their hypothesis by requiring subjects to learn variations of a tapping task that had either different (Experiment 1) or the same (Experiment 2) relative timing structure. In each experiment, subjects (N = 36) performed 270 acquisition trials with knowledge of results (KR) in either a blocked or a serial order. One day later, subjects performed 30 retention trials without KR. In data analyses, errors due to parameter modifications were dissociated from errors due to GMP construction to examine which process was responsible for the CI effect. In both experiments, parameter learning created a CI effect while GMP learning failed to produce a CI effect. In the light of these findings, a modification is proposed to the Magill and Hall (1990) hypothesis that takes into account these distinct processes in motor learning.