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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

At least 433 records · Page 24Linked to original sources
PubMed1995

ATP-hydrolyzing excitation state of the reconstituted alpha 3 beta 3 complex of ATP synthase from the thermophilic bacterium PS3: structural characteristics shown by time-resolved small-angle X-ray scattering with synchrotron radiation.

The ATP-hydrolyzing excitation state of the alpha 3 beta 3 complex of the ATP synthase from the thermophilic bacterium PS3 was investigated using time-resolved small-angle X-ray scattering with synchrotron radiation. The results showed the presence of the alpha 3 beta 3 complex at a steady state during ATP hydrolysis when the alpha 3 beta 3 hexamer reacted with Mg-ATP. The radius of gyration of the complex in the steady state was significantly larger than that of the Mg-AMP-PNP-hexamer complex, indicating a conformational change to an expanded structure during catalysis. This alpha 3 beta 3 complex dissociated into alpha 1 beta 1 heterodimers with apparent first-order reaction kinetics after all the ATPs were converted to ADPs. In contrast, when the alpha 3 beta 3 complex reacted with Mg-ADP, the complex dissociated into dimers with apparent first-order reaction kinetics without showing the steady state of the complex. The dimers, however, re-associated into the hexamer when Mg-ATP was added. The results were well-explained by a computer simulation based on non-linear chemical dynamics, in which a reaction mechanism that incorporates the dynamic structure of the hexamer in the steady state was considered.

Adenosine Triphosphate↗
PubMed1995

A case of distal 9q trisomy syndrome associated with an unusual inheritance of ABO blood type.

A male infant with distal 9q trisomy syndrome associated with an unusual inheritance of ABO blood type is reported. His clinical features were concordant with those of distal 9q trisomy syndrome. His karyotype was 46,XY, -10, +der (10) t(9;10) (q22.3;q24.3) confirmed by G-banding and high resolution methods. His father had the balanced translocation t(9;10) (q22.3;924.3). He had a blood type of AB, despite his father's blood type of AB and his mother's blood type of O. The gene of ABO blood type is located at 9q34.1-q34.2. Therefore, he would have received A and B type alleles from his father. 9q trisomy syndrome should be carefully investigated with ABO blood type.

ABO Blood-Group System↗
PubMed1995

Characterization of the endosymbiont of a deep-sea bivalve, Calyptogena soyoae.

We have purified DNA from gill tissue of a marine bivalve, Calyptogena soyoae, collected from the deep-sea cold seep communities in Sagami Bay, Japan. An rRNA gene was amplified, cloned, and sequenced. In situ hybridization revealed that the sequence is that of a bacterial endosymbiont within the gill of C. soyoae.

Animals↗
PubMed1995

Effect of mild hypothermia on the coefficient of oxygen delivery in hypoxemic dogs.

Hypothermia is one of therapeutic options in patients with severe acute respiratory failure. This study was designed to determine the optimum core temperature during hypoxemia by analyzing oxygen delivery (DO2) and consumption (VO2). Six dogs were ventilated using a mixed gas of N2 and air (fractional concn of O2 in inspired gas = 0.12) with total muscle relaxation under general anesthesia. Hypoxia (arterial PO2 approximately 35 Torr) was maintained during the experimental period. The core temperature was reduced progressively from 37 to 30 degrees C by surface cooling. The coefficient of oxygen delivery was defined as DO2 divided by VO2. In each animal, the DO2/VO2 was calculated by altering the core temperature by 1 degrees C, and its relative value was a third-order polynomial function of core temperature having a maximum value at a core temperature of 32.1 +/- 0.46 degrees C. At a core temperature of 32 degrees C, the blood lactate level was significantly lower than that at a core temperature of 37 degrees C (6.3 +/- 1.3 vs. 12.2 +/- 1.6 mg/dl; P < 0.05). The relative value of the DO2/VO2 was highest with limited lactate elevation at a core temperature approximately 32 degrees C. Under the condition of hypoxia, mild hypothermia approximately 32 degrees C may be optimal to improve oxygen demand-supply balance.

Animals↗
PubMed1995

Correlation between the adsorption tendency of cationic disinfectant onto a synthetic multibilayer and its minimum inhibitory concentration.

Minimum inhibitory concentration (the lowest concentration able to inhibit growth of microorganisms after 48 h contract) could be useful as a measure of bactericidal activity of cationic disinfectants. The relation between the minimum inhibitory concentration (microgram/ml) of cationic disinfectants against gram-negative microorganisms and the adsorption tendency of these compounds onto a lipid bilayer was therefore studied using a quartz crystal microbalance (QCM) coated with synthetic multibilayer film. The adsorbed amounts of these compounds were obtained from the frequency decrease of the QCM in aqueous solutions. The calculated partition coefficients showed a good correlation with the minimum inhibitory concentrations of cationic disinfectants against E. coli and K. pneumoniae, supporting the validity of this method for predicting minimum inhibitory concentration. The results suggest that effective antibacterial agents are only slightly absorbed, and may mostly penetrate through the lipid bilayer.

Adsorption↗
PubMed1995

[Protective effects of the stem of Berchemia racemosa Sieb. et Zucc. on experimental liver injuries].

The methanol extract and water extract from the stem of Berchemia racemosa (Rhamnaceae) showed protective effects on liver injuries induced by carbon tetrachloride (CCl4) and alpha-naphthylisothiocyanate (ANIT) in rats. The acetone extract of B. racemosa protected the liver injury induced by CCl4. One of the protective substances was identified as carpusin. Some fractions showed significant protective effects against the liver injury and cholestasis induced by ANIT.

1-Naphthylisothiocyanate↗
PubMed1995

Changes in coagulation and fibrinolytic system after local intra-arterial thrombolysis for acute ischemic stroke.

Intracerebral hemorrhagic transformation is one of the most important complications of thrombolytic therapy for acute ischemic stroke. The relationship between changes in markers for the coagulation and fibrinolytic systems and occurrence of hemorrhagic transformation was determined after local intra-arterial thrombolytic therapy using urokinase (UK) (24 patients) or recombinant tissue plasminogen activator (t-PA) (10 patients) within 6 hours of onset. All 34 patients had no hypodensity areas on initial computed tomography scans. Plasma concentrations of fibrinogen-fibrin degradation products (FDP), fibrinogen, alpha 2-plasmin inhibitor (alpha 2-PI), plasmin-alpha 2 plasmin inhibitor complex (PIC), thrombin-antithrombin III complex (TAT), and D-dimer were measured. Hemorrhagic transformation occurred in seven patients (21%) with complete or partial recanalization; four in the UK group and three in the t-PA group. Doses of the thrombolytic agents did not correlate with the incidence of hemorrhagic transformation. The FDP levels in the hemorrhagic transformation group treated with UK significantly increased immediately and 1 hour after the therapy. The alpha 2-PI activities decreased and PIC levels increased in both the hemorrhagic transformation and the nonhemorrhagic groups after the therapy. The TAT levels in both groups tended to be higher than the normal range, but there was no significant difference from the pretreatment levels. The D-dimer levels in the hemorrhagic transformation group were higher than those in the nonhemorrhagic group at 24 hours after the therapy. Furthermore, the D-dimer levels were significantly higher in patients with complete recanalization compared with those with none or partial recanalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Undifferentiated connective tissue syndromes (UCTS) accompanied by laryngeal involvement and autoimmune hepatitis].

Here we report a patient with undifferentiated connective tissue syndromes (UCTS) who developed hoarseness during exacerbation of autoimmune hepatitis. A 51-year-old woman was hospitalized in November 1993 because of hoarseness and liver dysfunction. She had demonstrated Raynaud's phenomenon, polyarthralgia and hoarseness since 1992. In August 1993, liver dysfunction was noted. On admission, laboratory data showed mild leukopenia, thrombocytopenia (WBC 3,900/mm3, platelet 12.4 x 10(4)/mm3), and elevations of transaminase (GOT 96 IU/l, GPT 79 IU/l) and IgG (4,556 mg/dl). Anti-nuclear antibody (ANA) and anti-smooth muscle antibody were positive. Other autoantibodies including anti-DNA antibody, anti-Scl 70 antibody were all negative. LE test and LE cells were also negative. On laryngoscopic examination, lesions that appeared similar to a bamboo-joint were noted at the middle of the bilateral vocal cords. Pathological findings of liver biopsy specimen were compatible with autoimmune hepatitis. She was treated with 30 mg of prednisolone. Polyarthralgia, hoarseness and the abnormalities of the transaminase levels improved rapidly. Laryngoscopic findings were also normalized. We considered this laryngeal involvement to be acute laryngitis accompanied by some UCTS, including a typical systemic lupus erythematosus (SLE) because of arthritis, cytopenia and ANA positivity. Involvement of the larynx in collagen disease is rarely mentioned in published reports.

Anti-Inflammatory Agents↗
PubMed1995

[Detection of Mycobacterium tuberculosis by amplification of mycobacterial DNA from pleural fluid and gastric juice: the comparison of IS6110 gene with Amplicor mycobacterium].

The polymerase chain reaction (PCR) using oligonucleotides based on the repetitive sequence (IS6110) of Mycobacterium tuberculosis and Amplicor Mycobacterium, which combines a PCR with the hybridization assay, were evaluated for detection of M. tuberculosis in pleural fluid and gastric juice. The detection limits of these two assay systems for cultured M. tuberculosis were less than 2 cells/ml, as compared with 200 cells/ml by culture. A total of 42 pleural fluid and 94 gastric juice specimens were examined. A total of 5 pleural fluid and 5 gastric juice were culture positive for M. tuberculosis. Only the PCR gave positive results in 2 pleural fluid of which laboratory findings are characteristic of tuberculous pleuritis, and in one gastric juice of the patient who was diagnosed as having pulmonary tuberculosis. Sensitivity, specificity and positive predictive value for IS6110 gene were 75%, 94% and 71.1%, respectively, in pleural fluid. Two of three positive specimens for IS6110 gene from pleural fluid were negative for Amplicor Mycobacterium. These specimens resulted in positive with Amplicor Mycobacterium when solvent extracted DNA was used. Both the PCR systems had the same sensitivity (80%), specificity (98.8%) and positive predictive value (83.3%) in gastric juice. The PCR systems would be useful for rapid detection of M. tuberculosis without long term culture and for detection of non-cultured one from pleural fluid as well as gastric juice. However, when the presence of an inhibitor of PCR is suspected in a specimen, DNA should be purified from the specimen before amplification.

Adult↗
PubMed1995

[Pulmonary malignant lymphoma associated with bilateral diffuse linear, reticular, and consolidated shadows].

A 72-year-old asymptomatic man was admitted to our hospital with abnormal chest radiographic findings: bilateral diffuse linear, reticular, and consolidated shadows. Malignant lymphoma (diffuse small-cell B-cell lymphoma) was diagnosed histologically after an open lung biopsy and was confirmed by a genetic examination. The lymphoma cells had infiltrated widely in various regions of the lung, including the alveolar spaces and walls, the bronchial and vascular spaces, and the pleura. This diffusion of the lymphoma cells might have accounted for the chest X-ray findings. Malignant pulmonary lymphoma should be included in the differential diagnosis patients with diffuse linear, reticular, and consolidated shadows on chest X-ray films.

Aged↗
PubMed1995

[Operative results in fourteen cases of paranasal sinus and anterior cranial fossa lesions surgically treated by an extended transbasal approach].

We describe the outcomes and complications of 14 patients with paranasal sinus and anterior cranial fossa lesions surgically treated by an extended transbasal approach, originally described by Kawakami, in our department. They were 10 patients with malignant tumors, 2 with benign tumors, and 2 with inflammatory diseases. A bifrontal craniotomy was performed using a high coronal skin incision, and the orbital rim and roof were removed after the dissection of the dura mater from the anterior skull base. Transcranial resection of the tumor was performed, and assisted by transnasal and transmaxillar resection using a nasal endoscope. Reconstruction of the anterior skull base was performed with the fasica lata and galeopericranial flap in all cases, temporal musculo-pericranial flap in 3 and free bone flap from the cranial convex in 3. Among 10 patients with malignant tumors (malignant melanoma; 4, squamous cell carcinoma; 2 adenocarcinoma; 1, malignant plemorphic adenoma; 1, chondrosarcoma; 1, and neuroblastoma; 1), total removal was performed in 5 patients and subtotal removal in 5 patients. Though local recurrence of the tumor was recognized in 6 patients, only one underwent additional surgery. Eight patients survived, and 2 patients died of systemic metastasis of the tumor and complications due to liquorrhea. Seven patients obtained a good quality of life, and the mean survival period in 8 patients still living was 27 months after the first surgery. In 2 patients with benign tumors (chordoma and osteoma), partial and total removal was performed. The patient with chordoma was operated on several times by this approach and the transoral approach, respectively. Each had a good postoperative course.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical evaluation of the small solitary pulmonary nodule].

The diagnostic process for small solitary pulmonary nodules was retrospectively analyzed. Three hundred and forty-three patients, each with a solitary pulmonary lesion of less than 3 cm on chest radiography, were evaluated. The patients were seen at our hospital between September 1986 and December 1993. They consisted of 138 with malignant diseases (114 with lung cancer and 24 with metastatic tumors), and 205 with benign diseases. There were 146 patients (71%) with benign lesions of less than 2 cm. The diagnosis in 118 patients (86%) with malignant disease was made by lung biopsy. Of these 118 patients, 19 underwent biopsy of the lung through a thoracoscope or open lung biopsy via a thoracotomy. Benign diseases were diagnosed in 167 patients (81%) by various laboratory tests and imaging techniques, including chest radiography. Thinsection CT was done in 132 patients. In 72 of these 132 patients (16 with lung cancer, 23 with metastatic tumors, and 33 with benign tumors), a judgement regarding whether the lesion was malignant or not could not be made. Therefore, open lung biopsy was done in 5 patients. Twenty-four patients were only observed, 43 underwent biopsy, and 35 underwent surgery. A decision tree needs to be established to select therapeutic options for management of patients whose diagnoses remain indeterminate even after thin-section CT. Formulation of a decision tree based not only on clinical findings but also on the results of diagnostic imaging is necessary to improve clinical decision making regarding small solitary pulmonary nodules.

Aged↗
PubMed1995

[Evaluation with transcranial Doppler ultrasonography of cerebrovascular CO2 reactivity modulated by arterial blood pressure].

We studied the effect of mean arterial blood pressure (mBP) on the cerebrovascular CO2 reactivity (K) by measuring the middle cerebral artery blood flow velocity (Vm) with transcranial Doppler ultrasonography (TCD) in 24 anesthetized patients. By measuring Vm during hypocarbia (po) and hypercarbia (er) at mBP of 60-120 mmHg, three kinds of K value were evaluated as follows: K(h), K(l), or K(c) = delta lnVm/delta PaCO2 = [lnVm(er)-lnVm (po)]/[PaCO2(er)-PaCO2 (po)], where K(h) was calculated between [Vm(er), PaCO2(er)] at a high mBP and [Vm(po), PaCO2(po)] at a low mBP; K(l), between [Vm(er), PaCO2(er)] at a low mBP and [Vm(po), PaCO2(po)] at a high mBP; K(c), at the same mBP corrected. The relationship between Vm and mBP showed a linear regression at each constant level of PaCO2. The K(h) shifted higher and the K(l) shifted lower in comparison with the K(c) following the widening of the mBP difference. The K(l) was affected especially by small variations of mBP. In conclusion, to evaluate simply the cerebrovascular CO2 reactivity modulated by mBP with TCD, K(h) may be acceptable as long as it is realized that the K(h) tends to be relatively high K value.

Adult↗
PubMed1995

[Stimulus effect and jumping of delayed potentials--investigation of human single nerve action potentials].

The jumping phenomenon is defined as an unexpected reduction in latency of evoked nerve responses with augmentation of stimulus intensity. This phenomenon may occur in the presence of segmental demyelination. To determine the severity of neuropathies, we recorded median nerve action potentials at the elbow of 60 patients of neuropathy by means of intraneural microneurography. Submaximal stimuli were delivered at the wrist or at one finger. In 53 of the 60 patients evaluated, delayed single nerve action potentials were recorded by submaximal stimuli that produced less than 10 microV compound nerve action potentials. In three delayed single unit potentials, latencies were shortened unexpectedly by several milliseconds when the intensity of stimulus was gradually increased. With the boundary stimulus intensity, we observed a small amplitude of the corresponding potentials at the delayed and the jumped latencies. Instead, jumping was suppressed with rapid repetitive stimuli. At the stimulus intensity sufficient to provoke jumping, we administered repetitive stimuli at 2Hz to 50Hz. At the rate of 20 to 30Hz, the corresponding potentials again returned to the delayed latencies. Rapid repetitive impulses may evoke cathodal hyperpolarization which raises the excitation threshold of the nerve. Thus, the stimulus effect can be decreased and jumping will be released. In addition, a diminution in amplitude and slight prolongation of the latency of each peak occurred in proportion to the increase in stimulus rate. However, paired stimuli with an interval of 4 to 13 msec was equivalent to a supernormal period and provoked the jumping of a single nerve unit. Conditioning stimuli may have increased the excitability of the corresponding fiber.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1995

[Intraneural topography of the median nerve at the elbow level--an analysis using intraneural neurography].

We examined intraneural topography of the median nerve at the elbow level by means of intraneural neurography in 38 individuals. A tungsten microelectrode was inserted into the median nerve trunk at the elbow where largest amplitude of the nerve action potential could be obtained with stimulations over median nerve trunk at the wrist. Each of six areas innervated by the nerve was stimulated supramaximally. The ratio of the amplitude of the nerve action potentials stimulated in each area to that stimulated over median nerve trunk at the wrist was arbitrary defined as territory index. the territory indices of six areas, i.e., thumb, index finger, middle finger, ring finger, little finger and thenar area, were 12%, 14%, 15%, 7%, 0% and 5%, respectively. Based on the investigation of permutations and combinations, the cutaneous fibers in the median nerve trunk at the elbow may be arranged in order of thumb-index-middle-ring fingers from the radial side, and the muscle fibers to the thenar muscles may be located at the palmar side to the index finger area. These results were in accordance with the previous reports obtained by near nerve recordings or anatomical analysis at the wrist. In 42% of the subjects a part of fibers in the median nerve were considered to innervate also little fingers, even though territory index was very small. This method has made it possible to estimate the intraneural topography of the median nerve at the elbow level and to detect Martin-Gruber anastomosis with a small number of sensory fibers.

Action Potentials↗