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Biomedical subjects

S Uchiyama

Publications and source records attributed to S Uchiyama.

At least 127 records · Page 7Linked to original sources
PubMed1995

Flexor tendon-pulley interaction after tendon repair. A biomechanical study.

Ten normal ring fingers from ten donors were used to determine the effect of flexor tendon repair on the gliding resistance between the tendon and the A2 pulley. Gliding resistance was measured for the intact FDP tendon and for the same tendon after it was cut transversely and repaired with a 4/0 Ticron core suture and a 6/0 running epitendinous nylon suture. After repair, the gliding pattern of the tendon through the A2 pulley changed significantly. The resistance and the friction coefficient were approximately doubled (P < 0.005).

Biomechanical Phenomena↗
PubMed1995

A randomized trial of E5510 versus aspirin in patients with transient ischemic attacks. The Japanese E5510 TIA study-1 (JETS-1) Group.

In a randomized double-blind trial, the Study Group compared the efficacy of E5510, a novel antiplatelet agent, and aspirin in preventing the recurrence of transient ischemic attacks (TIA). In total, 227 patients who suffered from TIA in the twelve weeks prior to the study were enrolled. They were randomly allocated to three treatment groups, ie, 71 patients in the E5510 4 mg group, 77 patients in the E5510 2 mg group, and 79 patients in the aspirin 324 mg group, and were treated for twelve to twenty-four weeks. The incidence of recurrent TIA or stroke was 21.5% in the aspirin group and was significantly lower in the E5510 groups, being 8.5% in the 4 mg group (P < 0.05) and 11.7% in the 2 mg group (P < 0.05). Adverse events were observed in 5 cases in the 4 mg group, in 8 cases in the 2 mg group, and in 10 cases in the aspirin group, but none of them were serious. Since safety was judged to be comparable among the three groups, E5510 appears to be an antiplatelet agent for the treatment of TIA with a clinical benefit over aspirin.

Aged↗
PubMed1995

Automated homogeneous liposome-based assay system for total complement activity.

We developed an automated homogeneous immunoassay, based on immune lysis of dinitrophenyl (DNP)-labeled liposomes, for measuring total complement activity. Liposome lysis caused by complement activity was detected spectrophotometrically from entrapped glucose-6-phosphate dehydrogenase activity. Complement activity in human sera was quantified by comparison with a calibration curve. For ease of application to fully automated routine clinical analyzers, we adopted a two-reagent system, one reagent containing a homogeneous population of small DNP-labeled liposomes and one containing antibody/substrate. This system required calibration only once a week. Within-run and between-run CVs were 0.4-1.3% (n = 10) and 1.8-4.7% (n = 10), respectively. Serum results were linear upon dilution (with saline) over a twofold range. Bilirubin, hemoglobin, Intrafat, and serum proteins such as rheumatoid factor, M protein, IgG, and IgA did not affect the assay results. The results (y) correlated well with those from a hemolytic complement activity test (x): y = 1.05x - 1.14, r = 0.92, on 66 samples in the range < 10- > 50 kU/L. This method should therefore be of great use for the determination of complement activity.

Adolescent↗
PubMed1995

[MR imaging of the anterior spinal artery in a case of bilateral vertebral arterial occlusion].

A 66-year-old woman, who had been suffering from frequent episodes of vertebro-basilar insufficiency for 10 years, was admitted because of brainstem ischemic symptoms. Magnetic resonance (MR) images were almost normal, but small flow voids were observed in front of the medulla oblongata and the upper cervical spinal cord. Cerebral angiography revealed that both of the vertebral arteries were completely occluded after branching off the respective posterior inferior cerebellar arteries. The basilar artery was fed only by a retrograde collateral flow via the anterior spinal artery which, arising from the left vertebral artery at the level of the fifth to sixth cervical vertebra, ascended the ventral aspect of the cord. These findings clarified that the flow voids on the MRI were from the anterior spinal artery, and were unusually prominent, as a collateral flow to the basilar artery. To the best of our knowledge, an anterior spinal flow void found on routine brain MR imaging has not been documented in the literature. Our case suggested that the flow void, a very small finding on the MRI, could be a useful sign in the diagnosis of serious vertebral arterial diseases.

Aged↗
PubMed1995

[A case of cerebral infarction in a young adult following an abuse of cocaine and other drugs].

We reported a case of cerebral infarction in a young adult following an abuse of cocaine and other drugs. A 27-year-old male was admitted to our hospital because of the abrupt onset of right hemiplegia and dysarthria. Brain CT and MRI examinations showed cerebral infarction in the region of the left caudate head and the left corona radiata. Cerebral angiography revealed total occlusion at the origin of the left middle cerebral artery, with neither vascular malformation nor atherosclerotic change. There were no obvious causes that might lead to cerebral infarction in young adults, including potential cardiac sources of embolism, abnormalities of blood coagulation, or collagen vascular diseases. From his history we learned he had started abusing cocaine and other drugs at the age of 16 years, and that he had been addicted to these drugs up to at least 2 months earlier than the onset of cerebral infarction, so we suggested his drug abuse might have affected the occurrence of cerebral infarction. We would like to emphasize that using 'drugs' should be taken into consideration as a possible cause of cerebral infarction in young adults.

Adult↗
PubMed1994

Ultrasonically guided percutaneous microwave coagulation therapy for small hepatocellular carcinoma.

BACKGROUND: The authors have used percutaneous microwave coagulation therapy (PMCT) as a new percutaneous local treatment for single unresectable hepatocellular carcinoma (HCC) measuring 2 cm or less in greatest dimension (small HCC). PMCT was used to attempt a cure of the disease. In this study, the efficacy of this treatment was assessed. METHODS: PMCT was performed on 18 patients with single small HCC. A microwave electrode (custom-made, 30-cm long by 1.6-mm thick) was inserted percutaneously into the tumor area under ultrasonic guidance. Microwaves at 60 W for 120 seconds were used to irradiate the tumor and surrounding area. RESULTS: After PMCT was administered, various image findings were correlated with tissue necrosis. At the tumor and surrounding area, ultrasonography showed echogenic change, contrast enhancement disappeared on contrast enhanced computed tomography, and magnetic resonance imaging (T2-weighted image) showed decreased intensity in all cases after treatment. Complete necrosis of the tumor area in a specimen obtained from one patient who underwent hepatectomy after PMCT also was confirmed. The treatment reduced levels of the tumor marker, alpha-fetoprotein, which had been high in some patients. Although the follow-up period was short (11-33 months), 17 patients remain alive. Local recurrence in the treated area has not been detected, and no serious side effects or complications have been encountered. CONCLUSIONS: PMCT may be an effective and safe treatment for small HCCs.

Adult↗
PubMed1994

Changes in muscle oxygenation during weight-lifting exercise.

The quantitative analysis of haemoglobin oxygenation of contracting human muscle during weight-lifting exercise was studied noninvasively and directly using near-infrared spectroscopy. This method was developed as a three-wavelength method which confirmed the volume changes in oxygenated haemoglobin (oxy-Hb), deoxygenated haemoglobin (deoxy-Hb) and blood volume (total-Hb; Oxy-Hb+deoxy-Hb). Nine healthy adult men with various levels of training experience took part in the study. Ten repetition maximum (10 RM) one-arm curl exercise was performed by all the subjects. Results showed that at the beginning of the 10-RM exercise, rapid increases of deoxy-Hb and decreases of oxy-Hb were observed. In addition, total-Hb gradually increased during exercise. These results corresponded to the condition of arm blood flow experimentally restricted using a tourniquet in contact with the shoulder joint, and they showed the restriction of venous blood flow and an anoxic state occurring in the dynamically contracted muscle. In three sets of lifting exercise with short rest periods, these tendencies were accelerated in each set, while total-Hb volume did not return to the resting state after the third set for more than 90 s. These results would suggest that a training regimen emphasizing a moderately high load and a high number of repetitions, and a serial set with short rest periods such as usually performed by body builders, caused a relatively long-term anoxic state in the muscle.

Adult↗
PubMed1994

Anatomical and radiological evaluation of the triangular fibrocartilage complex of the wrist.

109 wrists from 69 cadavers (mean age 74 years) have been studied to clarify the pathology and morphology of the triangular fibrocartilage complex (TFCC) and to correlate pathological and radiological findings. Perforation of the TFCC was observed in 65% of the specimens and was considered to be secondary to a degenerative process, because it was often accompanied by degenerative changes in the ulnar carpal bones and perforation of the lunotriquetral ligament. To detect TFCC perforations on plain postero-anterior radiographs, it is important to evaluate ulnar plus variance and degenerative changes in the ulnar carpus. Existence of ulnar plus variance alone is more sensitive but less specific in detection of TFCC perforation than the existence of degenerative changes in the ulnar carpus.

Aged↗
PubMed1994

Spinal cord potential recordings from the extradural space during scoliosis surgery.

For monitoring spinal cord functions during corrective surgery of scoliosis, we have recorded percutaneously from the posterior extradural space at the C5-7 levels the ascending conducted spinal cord potentials (ASCP) in response to extradural stimulation of the cauda equina in 134 patients. The ASCP consists of three spike-like components (C1, C2 and C3) followed by slow components. The extradurally recorded ASCP were not affected by anaesthetic agents. There were no significant differential effects of spinal distractions on each of the three spike potentials. There were no post-operative neurological abnormalities in patients whose ASCP showed no changes, amplitude increases, amplitude decreases of less than 50% or latency increases (> 0.2 ms) during spinal manipulations (no false negatives, but some false positives). Five patients who suffered postoperative neurological damage exhibited more than 50% changes in amplitude of the ASCP during surgery. All these neurological sequelae occurred in the first 80 patients. In the last 54 patients, in whom the distraction forces on the spine were controlled rapidly by observation of the amplitude changes in ASCP, there were no postoperative neurological abnormalities, except for one patient in whom an accidental spinal cord injury was produced by a hook. The results suggest that the distraction force on the spine must be reduced immediately when the amplitudes of the ASCP decrease by more than 50% of control values with or without latency increases.

Adolescent↗
PubMed1994

Shear-induced platelet aggregation in cerebral ischemia.

BACKGROUND AND PURPOSE: Recent evidence has suggested that shear-induced platelet aggregation is an important mechanism of thrombosis at arterial bifurcations or stenoses. We measured shear-induced platelet aggregation with a new apparatus in patients with cerebral ischemia and also studied correlations with other hemostatic parameters as well as the effect of antiplatelet agents. METHODS: The subjects were 75 patients with cerebral ischemia and 26 control subjects. Platelet aggregation was induced in citrated platelet-rich plasma by a high shear stress (108 dynes/cm2) that was applied by means of a cone-plate streaming chamber based on turbidimetry. We studied the correlation of test results with hemostatic parameters and also the effects of antiplatelet agents. RESULTS: Compared with the control subjects, an increase of shear-induced platelet aggregation was observed in 21 patients with atherothrombotic stroke and 12 with transient ischemic attacks, but not in 11 with cardioembolic stroke or 31 with lacunar stroke. There was no significant correlation of shear-induced platelet aggregation with platelet count, agonist-induced platelet aggregation, fibrinogen level, or beta-thromboglobulin level. The extent of shear-induced aggregation was not correlated with von Willebrand factor antigen levels but was significantly correlated with the amounts of larger von Willebrand factor multimers. Oral aspirin (81 mg/d) did not inhibit shear-induced platelet aggregation, whereas oral ticlopidine (200 mg/d) significantly inhibited it. CONCLUSIONS: These results indicate that shear-induced platelet aggregation is increased in patients with atherothrombotic stroke and transient ischemic attacks, is correlated with the increase of larger von Willebrand factor multimers, and is corrected by ticlopidine but not by low-dose aspirin.

Adult↗
PubMed1994

Fluorescence in the migrating pseudoplasmodium of the cellular slime mold Dictyostelium mucoroides.

Fluorescence was observed under light microscope in living cells and cell mass of Dictyostelium mucoroides. The fluorescence was localized in the vacuoles of live vegetative cells. While the cell mass of D. discoideum does not have a stalk during migration period, the cell mass of D. mucoroides has a stalk that forms at the beginning of the migration period. We were able to observe a preferential loss of the fluorescent vacuoles from the cells of the stalk and from the stalk-forming cells at the tip region of the slug. Although the fluorescence was also present in the mature spore mass of D. mucoroides, the fluorescence was not observed in the spores, but rather in the spaces between the spores within the spore mass. The fluorescent vacuoles in the cells of vegetative stage and of migrating slug stage may be related to the interspore fluorescence in the spore mass. Possible roles of the fluorescent substance(s) in amoebae, slugs and spore masses were discussed.

Animals↗
PubMed1994

[A study of absolute and relative growth on rat skeletal muscle].

Standard development of plantaris muscle in Wistar rats in relation to growth (2-86 weeks) was studied to define more reliable criteria of muscle hypertrophy and hyperplasia. The following variables were measured as indicators of respective factors; body weight and lower hind-limb length as physical factors, whole muscle weight and length as whole-muscle factors, and muscle fiber cross-sectional area, total fiber number and number of proliferating cell as intramuscular factors. When absolute growths were plotted against age, two stages were clearly observed for all factors. The transitional point for the two stage was observed at 10 weeks of age (about 300g in body weight). The first stage was a "growing phase" and the second was a "steady phase". When the relative growth was considered in relation to body weight, most factors increased in logarithmic functions, while muscle weight and muscle fiber cross-sectional area showed a linear relation. It was suggested, therefore, factors concerned with muscle mass and transverse growth developed more with increase in body weight than age. Furthermore, the increase in total fiber number and the decrease in number of proliferating cell in the "growing phase" showed mirror images, suggesting that most proliferating cells detected in the muscles in the "growing phase" may be myoblasts. These results assure the validity of muscle weight/body weight ratio in the evaluation of muscle hypertrophy or atrophy. However, it is remember that animals over 10 weeks of age (300g in body weight) should be used for correct evaluation of muscle hyperplasia for comparative or developmental studies of Wistar rats.

Age Factors↗
PubMed1994

[A case of cortical blindness confirmed by single photon emission computerized tomography and visual evoked potential].

We reported a rare case of cortical blindness in cerebral ischemia following post-anoxic state confirmed by single photon emission computerized tomography (SPECT) and visual evoked potential. A 45-year-old woman who had been suffering from bronchial asthma was admitted to our hospital because of sudden progressive dyspnea and depressed consciousness. When she arrived at the hospital by ambulance, she was in hypoxic state and fell into cardiac arrest. Her respiratory condition gradually improved with respirator assistance, and she recovered consciousness, but complained of bilateral visual loss. She had no history of any neurological or psychiatric illness, nor of drug abuse. On neurological examination, she was alert and oriented. Light reflex, optic fundi, extraocular movement and other neurological findings were all normal, with the exception of bilateral blindness. EEG showed generalized slow background activity, but cranial CT scan and MRI showed no abnormalities. 99mTc-HMPAO SPECT indicated hypoperfusion in prominent bilateral occipital and parietal lobes. Simultaneous recordings of pattern reversal visual evoked potential (VEP) and electroretinograms (ERG) using transient checkerboard pattern reversal in 15 min and 30 min checks were recorded. The results showed normal b waves but absent P100 in the bilateral eyes. From the patient's neurological symptoms and the results of SPECT and VEP, she was diagnosed as cortical blindness in post-anoxic state. On the 30th hospital day, her visual acuity and visual fields improved, but she was suspected of having visual agnosia. Eighty-five days after the onset of the neurological abnormalities, no traces of visual disturbances were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blindness↗
PubMed1993

Three-dimensional cytoarchitecture of complex branched fibers in soleus muscle from mdx mutant mice.

Three-dimensional cytoarchitecture and types and features of muscle fibers were examined in soleus muscles from mdx mutant mice at different stages of development. In the 2-week-old mice, no abnormal muscle fibers were observed light microscopically, whereas in the 4-week-old animals, disrupted fibers were frequent in light microscopy and scanning electron microscopy. Muscle fibers fused with several short fiber branches appeared at the sixth week after birth and increased in number until the tenth week. In the 1-year-old mice, approximately ten or more muscle fibers were seen fused together. They had many complex branches forming an "anastomosing syncytial reticulum." Muscle fibers with irregular diameters and aggregations of the same type fibers were also observed. Our results demonstrated that these complex branched fibers might be formed by long term repetition of the degeneration and regeneration cycle during the development of soleus muscles, indicating that the characteristic features of muscle fibers with irregular diameters and aggregations of the same type fibers are certainly dependent on the existence of the complex branched fibers.

Animals↗
PubMed1993

Allele frequency distribution of the D1S80 (pMCT118) locus polymorphism in the Japanese population by the polymerase chain reaction.

Population studies among Japanese were carried out at the D1S80 locus by the polymerase chain reaction and subsequent analysis in agarose gel electrophoresis. A total of 58 genotypes and 25 alleles ranging from 16 to 45 repeat units were observed in a population group of 121 unrelated individuals. The alleles with 18, 24 and 30 repeat units were found to be most common. Some large alleles with more than 42 repeat units were first observed in this study. Statistical tests for Hardy-Weinberg equilibrium showed that no significant deviations could be found in this Japanese population sample. The values of the mean exclusion chance and the discriminating power (DP) were calculated to be 0.76 and 0.91, respectively. The observed heterozygosity was 0.91.

Alleles↗
PubMed1993

Capsular infarcts: location, size and etiology of pure motor hemiparesis, sensorimotor stroke and ataxic hemiparesis.

We investigated the types of syndrome, location, size and presumed causes of 72 patients with acute capsular lacunar infarction. Clinical syndromes were classified into pure motor hemiparesis (PM), sensorimotor stroke (SM) and ataxic hemiparesis (AH). Lesion sizes of AH were significantly smaller than those of PM (p < 0.01) or SM (p < 0.01). When the lesion volume was classified into two groups, > or = 1 ml and < 1 ml, the large volume group had more frequent cardioembolic sources than the small volume group (41% and 18% respectively, p < 0.05). In AH patients no cardioembolic sources could be detected. Significant carotid stenosis was found in only 4% of patients. Patients with anterior choroidal artery territory infarction had infrequent cardioembolic sources (7%). The results suggest that the lesion size varies with clinical syndrome and some etiological trends are seen in the volume and the location of lesions.

Aged↗
PubMed1993

Alterations of haemostatic markers in various subtypes and phases of stroke.

The purpose of this study was to clarify differences in coagulation and fibrinolytic activation between the various subtypes and phases of ischaemic stroke. Haemostatic activation markers were measured in 52 patients with cardioembolic stroke, 32 with atherothrombotic stroke and 54 with lacunar stroke and compared with 23 age-matched controls. Data were obtained in the acute (< or = 7 days after onset), subacute (8-28 days) and chronic (> or = 29 days) phases of stroke. In patients with cardioembolic stroke, D-dimer and alpha 2-antiplasmin-plasmin complex levels were higher during the acute and subacute phases, while thrombin-antithrombin III complex levels were higher during the acute phase than in patients with lacunar stroke and controls. In cardioembolic stroke, fibrinopeptide A was increased during the acute and subacute phases, thrombin-antithrombin III complexes were higher during the subacute phase and D-dimer levels were higher during the chronic phase. Protein C activity was lower during the acute phase than in atherothrombotic stroke, lacunar stroke and controls. Protein C antigen was lower during the acute phase than in lacunar stroke and controls and during the chronic phase than in lacunar stroke. In contrast, only D-dimer levels were higher in atherothrombotic stroke patients than controls during the acute and chronic phases and no significant alterations in these markers were observed in the patients with lacunar stroke. These findings suggest that measurement of molecular markers of coagulation and fibrinolysis may be useful for detecting intracardiac thrombin and plasmin generation in patients with cardioembolic stroke.

Aged↗