Search PubMed⌕ Search

Biomedical subjects

S Uchiyama

Publications and source records attributed to S Uchiyama.

At least 91 records · Page 5Linked to original sources
PubMed1997

An experimental study of a combination method using a pedicle screw and laminar hook for the osteoporotic spine.

STUDY DESIGN: Using human cadaver spines, the authors compared the effect of using a combination of pedicle screw and laminar hook on the same vertebra with that of using a pedicle screw alone in reference to bone mineral density of the vertebra under nondestructive cyclic loading. OBJECTIVES: To quantify stiffness obtained by pedicle screw alone and by the combination method and to clarify a relationship between stiffness obtained by each instrumentation method and bone mineral density of the vertebra. SUMMARY OF BACKGROUND DATA: The use of pedicle screws apparently improves the union rate of spinal fusion. Instrumentation failures sometimes occur, however, such as loosening or loss of correction of the spine, especially in patients with osteoporosis. Some augmentation method in instrumentation is necessary to overcome bone fragility in the osteoporotic spine. METHODS: Thirteen cadaver lumbar vertebrae were used for this study. Bone mineral density was measured by dual-energy X-ray absorptiometer. After separating each vertebrae, the pedicle screw was screwed into a vertebra. Five cycles of cephalocaudal loading were performed to the shank of the screw with a cross-head speed of 3 mm/min under a maximum load control of 29.4 N using an Instron type testing machine, and the stiffness obtained with the pedicle screw (Kj) was calculated from the load-deformation curve. Then, a laminar hook was set and connected to the screw via a rod. Mechanical testing was performed in the same way, and the stiffness obtained with the combination method (Kf) was determined. Kj and Kf were compared using the paired t test. The relationship between Kj, Kf, or the stiffness improvement ratio ([Kf-Kj]/Kj) by the combination method and bone mineral density was analyzed by linear regression analysis. RESULTS: Stiffness obtained by the combination method was significantly greater than that obtained by pedicle screw alone (89.8 +/- 35.0 N/mm by the combination method, 60.2 +/- 19.6 N/mm by pedicle screwing alone; P < 0.0001). Stiffness, whether obtained by pedicle screw alone or by the combination method, was positively correlated with bone mineral density (with pedicle screw alone, R2 = 0.614, P < 0.0001; with the combination method, R2 = 0.645, P < 0.0001). However, there was no significant correlation between stiffness improvement ratio and bone mineral density. CONCLUSION: Instrumentation stiffness obtained by the combination method was significantly greater than that obtained by the use of pedicle screw alone. There was no significant correlation between the improvement ratio by the combination method and bone mineral density. These results suggest that the combination method is valuable irrespective of the presence of spinal osteoporosis.

Aged↗
PubMed1997

Time-course ultrasonographic observation of a mesenteric pseudocyst of the sigmoid colon: report of a case.

A 35-year-old woman was referred to our hospital for investigation of lower abdominal pain and a feeling of fullness. At her first consultation, a transvaginal ultrasonography (US) revealed a homogeneous cystic mass in the lower abdomen. Over a period of 8 months the US findings of the content of this mass changed from fine and faint internal echoes to moderate amounts of irregularly contoured internal echoes. At laparotomy, the cystic mass, which measured 3.0 x 3.0 x 3.5 cm, appeared to arise in the sigmoid mesocolon and tightly adhered to the appendix. The cyst was unilocular and contained a slightly yellow gelatinous fluid. Microscopically, its wall was fibrous and lacked an epithelial lining, suggesting that it was a so-called pseudocyst arising from the sigmoid mesocolon. To our knowledge, this is the first case report documenting the time-course ultrasonographic observations of a mesenteric pseudocyst. Our findings suggest that the time-elapsed ultrasonographic changes might have been dependent on the interval between the onset of cystic formation and the US examination.

Adult↗
PubMed1997

Normal kinematics of carpal bones: a three-dimensional analysis of carpal bone motion relative to the radius.

Normal carpal kinematics were studied in 22 cadaver specimens using a biplanar radiography method. The kinematics of the trapezium, capitate, hamate, scaphoid, lunate, and triquetrum were determined during wrist motion in sagittal and coronal planes. The results were expressed using the concept of the screw displacement axis and converted to describe the magnitude of rotation about and translation along three axes (X-axis: pronation-supination axis, Y-axis: flexion-extension axis, and Z-axis: radial-ulnar deviation axis) commonly used for the wrist. The orientation of these axes is expressed relative to the radius. Within the proximal carpal row, considerable differences of carpal behavior around the Y-axis were observed during sagittal plane motion of the wrist. The scaphoid exhibited the greatest magnitude of rotation, and the lunate the least. The magnitude of rotation of the carpal bones around the X-axis during sagittal plane motion of the wrist was small. The proximal carpal bones exhibited some ulnar deviation in 60 degrees of wrist flexion. During coronal plane motion of the wrist, the magnitude of radial-ulnar deviation of the distal carpal bones was mutually similar and generally of a greater magnitude than that of the proximal carpal bones. The proximal carpal bones experienced some flexion during radial deviation of the wrist and extension during ulnar deviation of the wrist. Translation was generally minimal in all carpal bones throughout wrist motion. This study reports results from the largest cadaver wrist kinematics study completed to date. The accuracy of the current method was improved when compared to previous studies. A sufficient number of specimens to allow statistical comparison was used and minimal interspecimen variability was noted. This study enabled a precise description of quantitative analyses of normal carpal kinematics relative to the radius.

Adult↗
PubMed1997

Alterations of platelet, coagulation, and fibrinolysis markers in patients with acute ischemic stroke.

Alterations of platelet, coagulation, and fibrinolysis markers were investigated to determine the indications for antithrombotic therapy in patients with different clinical categories of acute cerebral infarction. Marked platelet activation was observed in platelet function tests, including measurements of platelet-specific proteins and platelet survival, platelet scintigraphy in the brain, and platelet fibrinogen binding assay, in patients with atherothrombotic stroke. Among patients with atherothrombotic stroke, increases of thrombin-antithrombin III complex (TAT) and D-dimer were frequent in addition to the findings of platelet activation in patients showing progressing stroke. Patients with cardioembolic stroke demonstrated marked elevation of coagulation markers, TAT and fibrinopeptide A, and fibrinolysis markers, D-dimer and plasmin-alpha2-plasmin inhibitor complex, as well as platelet activation. In contrast, neither activation was seen in patients with lacunar stroke. On the basis of these findings, antiplatelet therapy is indicated for stable or improving stroke, whereas anticoagulant therapy is indicated for progressing stroke among patients with atherothrombotic stroke. In patients with cardioembolic stroke, anticoagulant therapy should be started as soon as possible, or should be followed by thrombolytic therapy in the hyperacute phase. However, further investigation appears necessary for recommendations for patients with lacunar stroke.

Acute Disease↗
PubMed1997

Germline mutations of the MEN1 gene in Japanese kindred with multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome. The responsible gene MEN1 has recently been isolated, and its germline mutations have been identified in affected individuals in the United States, Canada and Europe. We screened for MEN1 mutations by direct nucleotide sequencing of all protein-coding regions, and identified five distinct germline mutations in five among six Japanese kindreds with familial MEN1 or familial hyperparathyroidism. The mutations were dispersed across the gene. These findings suggest that, because of the absence of an obvious founder effect, the entire MEN1 gene region should be examined for germline mutations in the probands of MEN1 and related syndromes in Japanese families.

DNA, Neoplasm↗
PubMed1997

Morphological and biochemical evidence of muscle hyperplasia following weight-lifting exercise in rats.

We used a rat model of weight lifting to examine the serial biochemical and morphological changes following muscle fiber hyperplasia during 14 days of exercise. [3H]thymidine and [14C]leucine labeling were used to determine the serial changes in cellular mitotic activity and the level of amino acid uptake and myosin synthesis. Morphological changes were assessed with light and transmission electron microscopy, whereas proliferation of cells was evaluated immunohistochemically with 5-bromo-2'-deoxyuridine (BrdU). The intensity of the exercise and degree of muscle damage were monitored by serum creatine kinase (CK) activity. Damaged fibers were sparsely distributed, and a significant CK leakage was observed 30-60 min after exercise. Anti-BrdU-positive cells were observed in damaged fibers and at the periphery of undamaged fibers. Changes typical of muscle regeneration were observed; however, the formation of new fibers in the interstitial space was also evident. The mitotic activity also changed and reflected the appearance of anti-BrdU-positive cells and activated satellite cells. Amino acid uptake increased during the first week of exercise, probably reflecting muscle hypertrophy and synthesis of other noncontractile related proteins. The uptake also increased during the second week, probably due to hyperplasia, a finding also supported by electron microscopy. Our results suggest that one bout of weight-lifting exercise in untrained rats induced muscle hyperplasia following regeneration. The process of muscle hyperplasia was activated by muscle fiber damage in our model.

Animals↗
PubMed1997

Appearance of complex branched muscle fibers is associated with a shift to slow muscle characteristics.

To examine the effects of numerous complex branched fibers (CBF) on whole muscle contractile properties, we established a model of myopathic muscles containing a large number of CBF by repeated local injection of bupivacaine hydrochloride (Marcaine) into the plantaris (PLA) muscle. Marcaine injections were administered once weekly for 10 weeks into the right PLA muscles of Wistar male rats. The in situ contractile properties of Marcaine-injected PLA muscles (I-PLA) were examined under urethane anesthesia, and compared with the contralateral (control) PLA muscle (C-PLA). Numerical and morphological examination using the modified nitric acid fiber digestion method and scanning electron microscopy showed that Marcaine resulted in an 8-fold increase in the number of branched fibers in the I-PLA muscles and about 70% of these fibers were CBF. The latter were composed of ten or more muscle fibers fused together along with many thin and thick, long and short daughter branches. The time to peak tension of twitch and tetanus, and 1/2 relaxation time were significantly longer in I-PLA muscles, representing a shift to slow muscle characteristics. However, the total area of slow fibers/muscle cross-sectional area was similar in I-PLA and C-PLA muscles. Aggregates of same-type fibers (slow fibers) with small and large diameters were observed, reflecting an expected cross-sectional property of CBF. Our results suggest that the appearance of several CBF in a muscle is associated with a shift towards slower contractile properties in the affected muscle.

Anesthetics, Local↗
PubMed1997

Osteosynthesis without instrumentation for vertebral pseudarthrosis in the osteoporotic spine.

We have performed simple bone grafting in four elderly patients with pain due to unstable pseudarthroses in the osteoporotic spine after compression fracture. At operation, we observed abnormal movement of the affected vertebral body which was covered with a hypertrophic membrane; this seemed to inhibit the blood supply to the lesion. The thick membrane and avascular granulation in the false joint were excised and bone grafting carried out. Symptoms were dramatically improved immediately after operation and bony union was confirmed in the three surviving patients.

Aged↗
PubMed1997

Gliding resistance of extrasynovial and intrasynovial tendons through the A2 pulley.

The gliding ability of the flexor digitorum profundus tendon and of the palmaris longus tendon through the A2 pulley was compared, in terms of gliding resistance, with use of a system that we developed. Fourteen digits and the ipsilateral palmaris longus tendons from fourteen cadavera were used. The average gliding resistance at the interface between the palmaris longus tendon and the A2 pulley was found to be greater than that between the flexor digitorum profundus tendon and the A2 pulley under similar loading conditions. We concluded that the gliding ability of the palmaris longus tendon was inferior to that of the flexor digitorum profundus tendon in vitro.

Biomechanical Phenomena↗
PubMed1997

Boundary lubrication between the tendon and the pulley in the finger.

The lubrication mechanism between the human flexor digitorum profundus tendon and the A2 pulley was investigated in vitro. The gliding resistance at the interface between the tendon and the pulley increased significantly after the tendon had been treated with a hyaluronidase solution. Alcian-blue staining of the surface of the tendon before and after it was treated with hyaluronidase suggested the presence of hyaluronate complex. Alcian blue-positive and hyaluronidase-sensitive materials, such as hyaluronate or proteoglycan, in the synovial membrane and the matrix of the tendon, may act as a boundary lubricant, facilitating the gliding and reducing the resistance between the tendon and the pulley.

Alcian Blue↗
PubMed1997

[Accuracy of three-step diagnosis in discriminating subtypes of acute ischemic stroke].

The aim of this study is to evaluate the accuracy of three-step diagnosis in discriminating subtypes of acute ischemic stroke. A total of 120 consecutive patients with first-ever ischemic stroke, admitted to one general hospital, were prospectively studied. In the first step (within 24 hours of clinical onset), the first diagnosis was made according to clinical symptoms and signs, and patients were subdivided into four groups according to the classification of Oxfordshire Community Stroke Project: lacunar infarcts (LACI), total anterior circulation infarcts (TACI), partial anterior circulation infarcts (PACI), and posterior circulation infarcts (POCI). In the second step (24 hours to 72 hours from the onset), neuroimaging diagnosis was performed by CT and/or MRI. Four lesion sites were classified: 1) small subcortical infarction < or = 1.5 cm in diameter in the perforating artery territory (SSI), 2) supratentorial cortical or striatocapsular infarction (CI), 3) low-flow infarction (LFI) which includes centrum semiovale infarct and internal junctional infarct, and 4) posterior circulation infarction other than SSI (PI). In the third step, etiological diagnosis was made by examination including trans-thoracic echocardiography and MRA (3-D, PC). In accordance with the TOAST Study, the presumed stroke mechanism was categorized as either small-vessel occlusion (lacune), cardioembolism (CE), large-artery atherosclerosis (LAA), or others. The majority of patients with TACI, PACI or POCI showed the corresponding lesions on CT or MRI, while only 69% of LACI patients demonstrated SSI. Seventy-five percent of patients with TACI were categorized as CE in the third diagnosis, while the etiology of the patients with PACI was either CE or LAA in equal numbers. Only 60% of LACI patients were classified as lacune and 21% of them as LAA. Patients with LACI but classified as LAA usually had atypical clinical symptoms (e.g. monoparesis) and lesions other than SSI. The positive predictive value (PPV) of lacune in the combination of LACI and SSI was 0.75. Eighty-two percent of patients with CE had atrial fibrillation (af), which was the most frequent cardioembolic source. When patients with TACI or PACI had af, the PPV of CE was 0.93, but when they did not, the PPV of LAA was only 0.68. The etiology of POCI was variable. In conclusion, the agreement of the three-step diagnosis is considerable, but more rigorous clinical examination is needed for some clinical groups (POCI and LACI) and the etiological diagnosis of LAA.

Adult↗
PubMed1997

[Small hand muscle atrophy as an initial sign in HTLV-I associated myelopathy].

A 68-year-old female had been well until the age of 52 when she noticed weakness and atrophy of her right small hand muscles. She began to have gait disturbance at the age of 63. On admission, neurological examinations revealed atrophy and weakness of the small hand muscles on both sides as well as spastic paraparesis. As the antibody titer for human T-lymphotropic virus type I (HTLV-I) was elevated both in the serum and CSF, a diagnosis of HTLV-I associated myelopathy (HAM) was made. Electrophysiological studies showed neurogenic changes and suggested anterior horn cell involvement. After oral administration of prednisolone, her spasticity and gait disturbance improved slightly. Small hand muscle atrophy can be one of the initial signs of HAM, and may mimic amyotrophic lateral sclerosis and cervical spondylosis.

Aged↗
PubMed1997

[A case of basilar artery occlusion associated with one-and-a-half syndrome, paralytic pontine exotropia and WEBINO-syndrome].

We report a 79-year-old woman with basilar artery occlusion. She had a sudden onset of tetraplegia and disturbed consciousness, and within four days from the onset she showed a varied, fluctuating eye symptoms. On admission, she showed ocular bobbing, skew deviation with the right eye lower-positioned, upward gaze palsy, one-and-a-half syndrome, and paralytic pontine exotropia (PPE). On the third day after the onset, she showed wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome, and on the fourth day, she showed one-and-a-half syndrome again. Her right-gaze palsy improved repeatedly, and on the 19th day from the onset, only right MLF syndrome remained. Her eye symptoms fluctuated probably according to the distal migration of emboli, there by the responsible lesion and the mechanism of these eye symptoms are considered to be closely inter-correlated. On the fourth day after onset, the magnetic resonance imaging revealed cerebral infarctions in bilateral middle pons, the left paramedian lower pons, and the right paramedian midbrain, and a hemorrhagic infarction in the right inferior cerebellar hemisphere. We believe that that the eye symptoms of this patient were caused by lesions in the paramedian midbrain or pons.

Aged↗
PubMed1997

[CT-guided lung needle biopsy using a new supporting implement].

We contrived a new supporting implement to increase the hit rate of CT-guided needle biopsy (CTNB) for localized pulmonary lesions. Using this implement, twenty-two CTNB examinations for localized pulmonary lesions were performed. In 21 out of the 22 examinations (95%), the lesions were hit, and specimens appropriate for cytological or histological diagnosis were obtained. The course of needle insertion, which was difficult to define in the past, has become to be easier and more precise with this method. Using this new implement, CTNB is now applicable to smaller and deeper lesions.

Adult↗
PubMed1997

[A case of paradoxical cerebral embolism with 'spectacular shrinking deficit'].

A 66-year-old woman was admitted to our hospital because of abrupt onset of left hemiparesis and confusional state. Ten hours prior to admission, she developed difficulty in left hand movement, and her family noticed cloudiness of consciousness and gait disturbance. Neurological examination revealed only a hollow hand sign of the left hand without other neurological deficits. Cranial CT showed a low density area in the right superior parietal region, and the follow up CT on 6th hospital day exhibited contrast enhancement and hemorrhagic transformation in this area. Cerebral angiography demonstrated capillary blush and early venous filling in the right posterior parietal region. Transesophageal color-coded Doppler echocardiography (TEE-CD) showed a shunt flow via patent foramen ovale (PFO). Thus, we diagnosed this case as paradoxical cerebral embolism through PFO, which is characterized by rapid recovery of clinical manifestation, so-called spectacular shrinking deficit. Even in elderly patients with embolic stroke of unknown origin, TEE-CD should be performed to investigate PFO.

Aged↗
PubMed1997

[Neurosarcoidosis with an alternating and recurrent external ophthalmoplegia].

We report a 62-year-old woman who was admitted to our hospital because of abrupt onset of ptosis, and alternating and recurrent bilateral external ophthalmoplegia in a short period without pupillary sphincter muscle abnormality. She had been suffering from uveitis of unknown origin for four years before admission, which was improved with the local administration of steroid. Her brain CT and MRI showed a parasellar mass lesion, and cerebral angiography revealed total occlusion of the right internal carotid artery with little arteriosclerotic change in other blood vessels. She was diagnosed as having sarcoidosis because of elevated serum creatinine kinase and lysozyme levels, and the pathological finding of granuloma in muscle biopsy. The oral administration of prednisolone resulted in disappearance of her external ophthalmoplegia completely in ten months. We postulate that in this patient, the alternating and recurrent external ophthalmoplegia in a short period was related to ischemic neuropathy caused by vascular lesion of neurosarcoidosis.

Cranial Nerve Diseases↗
PubMed1996

The Bacillus subtilis chromosome region near 78 degrees contains the genes encoding a new two-component system, three ABC transporters and a lipase.

The nucleotide sequence of a 9444-bp segment around the 78 degrees region of the Bacillus subtilis (Bs) chromosome has been determined. Nine putative orfs were identified. The deduced amino acid sequences of the products of two of them (yfiJ and yfiK) exhibit high similarity to those of a sensor protein, DegS, and a transcriptional regulatory protein, DegU, of Bs, respectively. Three of them (yfiL, yfiM and yfiN) seem to be ABC transporter genes. One orf (designated as lipB), the closest to the sspE among the nine orfs, is the second lipase gene in Bs.

ATP-Binding Cassette Transporters↗