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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 739 records · Page 41Linked to original sources
PubMed1990

Neuromuscular effects of respiratory and metabolic acid-base changes in vitro with and without nondepolarizing muscle relaxants.

The effects of metabolic (bicarbonate, [HCO3]) and respiratory (carbon dioxide, PCO2) acid-base changes on indirectly elicited twitch tension with and without nondepolarizing neuromuscular blocking agents were compared in a rat phrenic nerve-hemidiaphragm preparation. Ionized calcium [Ca2+] and magnesium [Mg2+] concentrations in the modified Krebs' solution were measured and kept constant. Likewise, twitch was altered when pH changes were produced by altering either PCO2 or [HCO3]. Decreasing pH either by increasing PCO2 or by decreasing [HCO3] significantly decreased (P less than 0.01) twitch, by 9.5 +/- 0.6 (SEM, n = 8) and 10.6 +/- 1.5%, respectively. Increasing pH by decreasing PCO2 or by increasing [HCO3] significantly increased (P less than 0.01) twitch, by 5.6 +/- 0.9 and 7.9 +/- 0.6%, respectively. After a partial depression of twitch by nondepolarizing neuromuscular blocking agents, the effects of PCO2 and [HCO3] changes were again assessed. Decreasing pH by increasing PCO2 or by decreasing [HCO3] intensified d-tubocurarine (dTc) (28.2 +/- 1.6 and 32.0 +/- 2.9%, respectively) and vecuronium (23.0 +/- 1.4 and 36.8 +/- 3.2%, respectively) block, whereas it reversed metocurine (1.2 +/- 2.2% NS and 2.9 +/- 1.3%, respectively) and pancuronium (8.3 +/- 1.5 and 11.5 +/- 3.0%, respectively) block. Conversely, increasing pH by decreasing PCO2 or by increasing [HCO3] antagonised dTc (12.8 +/- 2.2 and 13.6 +/- 1.8%, respectively) and vecuronium (25.3 +/- 1.7 and 25.0 +/- 3.0%, respectively) block, whereas it potentiated metocurine (4.2 +/- 0.6 and 8.0 +/- 1.1%, respectively) and pancuronium (11.0 +/- 1.2 and 17.5 +/- 2.0%, respectively) block. Except where indicated, all changes in block described above were statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Imbalance↗
PubMed1990

Production of interleukin 1 alpha by a trichilemmoma cell line.

In order to obtain a good source of human epidermal cell derived thymocyte activating factor (ETAF) for biological study, several cell lines of epidermal origin were cultured. One of the trichilemmoma cell lines, KTL-1, was found to produce ETAF satisfactorily in its culture supernatant. The culture supernatant was collected and analyzed to determine the nature of the ETAF activity. The ETAF activity was completely inhibited by anti-IL 1 alpha antibody, but not by anti-IL 1 beta antibody. Messenger RNA expression by KTL-1 cells was analyzed by using cDNA of IL 1 alpha as a probe. Messenger RNA was not detected in KTL-1 cells by either dot blot analysis or northern blot analysis. However, it was expressed weakly in the cytoplasm by in situ hybridization technique. Messenger RNA expression was easily detected in KTL-1 cells stimulated by lipopolysaccharide (LPS). Messenger RNA expression reached a peak at 3 hours after stimulation of LPS. A trichilemmoma cell line, KTL-1, can be a good source of human ETAF for biological study.

Blotting, Northern↗
PubMed1990

Pro-subtilisin E: purification and characterization of its autoprocessing to active subtilisin E in vitro.

The formation of active subtilisin E from pro-subtilisin E requires the removal of the N-terminal pro-sequence of 77 residues. Pro-subtilisin E produced in Escherichia coli using a pINIII-ompA vector was first extracted with 6 M guanidine-HCl and 5 M urea and purified to homogeneity in the presence of 5 M urea. Upon drop dialysis against 0.2 M sodium phosphate buffer (pH 6.2), the purified pro-subtilisin in 5 M urea was processed to active subtilisin of which the N-terminal sequence and migration in SDS-polyacrylamide gel electrophoresis were identical to those of authentic active subtilisin E. This process was found to be very sensitive to the ionic strengths and anions used. Under the optimum conditions (dialysis against 0.5 M (NH4)2SO4 and 1 mM CaCl2 in 10 mM Tris-HCl buffer (pH 7.0) at 4 degrees C for 1 h), approximately 20% of pro-subtilisin E was converted to active subtilisin E. The activation process was not inhibited by Streptomyces subtilisin inhibitor, and pro-subtilisin E in which the active site was mutated (Asp32 to Asn) was unable to be processed under the optimum conditions. These results confirmed the previous hypothesis that the processing of pro-subtilisin occurs by an intramolecular, autoprocessing mechanism.

Ammonium Sulfate↗
PubMed1990

Changes in negative symptoms of schizophrenic patients two years later.

This study investigated the course of negative symptoms by examining the psychiatric symptoms of 59 new schizophrenic patients at the first consultation and again two years later using a structured interview--the Present State Examination. An examination of the total score of the nine negative symptoms, included in the "Chronic Schizophrenic Syndrome" by Wing, showed that 27 out of the 59 patients (45.8%) had lower symptom scores two years later than they did at the first consultation ("negative symptom improvement" group), while 20 patients (33.9%) had higher scores two years after the first consultation ("negative symptom deterioration" group). There were 12% more patients in the improvement group than in the deterioration group. No significant differences were observed between the "improvement group" and "deterioration group" in relation to the following factors--subclassification of schizophrenia, mode of onset, age at the first consultation, marital status at the time of onset, academic history, employment status prior to the onset, the history of hospitalization after the onset and maintenance therapy of neuroleptics. In relation to psychiatric symptoms at the first consultation, the patients in the "improvement group" had a variety of symptoms compared to the patients in the "deterioration group," and the presence of "incoherence of thought," "delusion of reference" and "special features of depression" was significantly higher in the improvement group than in the deterioration group.

Adolescent↗
PubMed1990

A new approach for the filtrate regeneration system in the wearable artificial kidney.

In the filtrate and/or dialysate regeneration system, which is expected to miniaturize the artificial kidney, ammonium ion decomposed from urea by immobilized urease is removed competitively by ion-exchangers from coexisting cations. Since divalent cations such as Ca2+ and Mg2+ are more favorably exchanged than ammonium ion, this system needs supplementation of these cations and, thus, additional amount of ion-exchanger. To minimize these requirements, we utilized positively charged membrane to process cation-free filtrate in which urea is dialyzed. Positively charged membranes were tested in vitro to evaluate separation efficiency between urea and cations. Equilibrium adsorption of ammonium ion to ion-exchanger with or without co-existing cations demonstrates that this filtrate regeneration system can reduce the amount of ion-exchanger up to one-half to one-third of that of the conventional system. In an ex vivo experiment with a mongrel dog, blood urea nitrogen (BUN) concentration was maintained at the same level or up to 23% less than the initial value.

Aluminum Silicates↗
PubMed1990

Filtration of fresh frozen plasma used as substitution fluid in plasma exchange in order to remove microaggregates.

Freshly melted fresh frozen plasma (FFP) contains a large number of particles smaller than 20 microns in diameter. These particulate materials (microaggregates) consist of aggregated triglyceride-rich lipoproteins (LA) and precipitable aggregates closely resembling fibrin (FA). Both LA and FA injected into a rat's tail vein were trapped in the lung and formed emboli in the pulmonary arterioles. To prevent the passage of these microaggregates into the systemic circulation, a new circuit was devised for plasma exchange containing a filter with a pore size of 0.2 microns. In 17 patients with fulminant hepatitis who received plasma exchange transfusions and subsequently died and were autopsied, the incidence of pulmonary complications was significantly lower in the 12 patients who received filtered FFP. According to these results, the possibility of pulmonary complications due to micro-embolism developed by microaggregates in FFP should be taken into account when a large amount of FFP is repeatedly infused into critically ill patients.

Animals↗
PubMed1990

Development of computer-aided motion analyzing (CAMA) system for radiopaque implanted tilting disk heart valves.

The newly developed semiautomatic data acquisition and processing system allows progress in quantitative evaluation of functions of implanted tilting disk valves. In the new system, data acquisition could be carried out semiautomatically by utilizing image processing methods, and the data analysis time was shortened. The system consists of a computer-controlled cinefilm loading device, a CCD camera, a frame memory, a superimposer, and CRT displays. Since series of the open- and shut-mode frames are commonly observed by turns in normal subjects, data acquisition was carried out manually at the first frame of each mode and semiautomatically from the second frame to the last. By processing the image data with the binarization method, the valve contours were detected, and an open angle and other motion properties can be obtained. Analyzing 90 frames of the cinefilm, this system analyzes data in a time period 20 min shorter than the manual procedure. With the implanted Medtronic Hall valve, a 60 to 65 degrees open angle was calculated.

Cineradiography↗
PubMed1990

Acute respiratory failure in multiple sclerosis.

A 23-year-old woman developed acute respiratory failure in the course of multiple sclerosis. The lack of bulbar dysfunction, the presence of quadriplegia, and the bilateral diaphragmatic weakness indicated the presence of spinal cord lesions involving pyramidal tracts bilaterally. Magnetic resonance imaging revealed a cervical demyelinating lesion between C1 and C3.

Acute Disease↗
PubMed1990

Transient neuromuscular impairment resulting from prolonged inhalation of halothane and enflurane.

Inhalation anesthesia first with halothane followed by enflurane relieved a patient with status asthmaticus who was refractory to conventional therapy including mechanical ventilation. After 13 days of anesthesia while on mechanical ventilation and employing nondepolarizing muscle relaxants, significant neuromuscular impairment, manifested by tetraplegia and sensory disturbance, developed. Anesthesia was discontinued on day 14, and the patient was weaned from mechanical ventilation on day 16. Over the next two months, the neuromuscular impairment markedly improved. Halothane was associated with cardiac arrhythmias and hepatitis necessitating replacement by enflurane. Enflurane appeared to be as effective a treatment for refractory asthma as halothane. The most probable cause of the neuromuscular impairment in our patient was the long-term use of inhalation anesthetics or nondepolarizing muscle relaxants.

Adult↗
PubMed1990

Continuous positive airway pressure breathing in supine and upright postures.

Continuous positive airway pressure (CPAP) breathing of 10 cmH2O was applied to 10 healthy conscious subjects both in supine and 70 degree head-up postures. CPAP increased the end-expiratory lung volume from 2.44 +/- 0.66 (S.D.) to 3.07 +/- 0.68 liters in supine subjects, and from 3.01 +/- 0.57 to 3.64 +/- 0.57 liters in head-up subjects. During CPAP, rib cage motion became predominant when compared to abdominal motion in upright posture. Among the respiratory parameters, inspiratory duration was significantly shortened during CPAP in either posture, but was changed less significantly by individual posture change alone. Mean inspiratory flow decreased during CPAP only in upright posture. Abdominal muscles were recruited for expiration during CPAP in either posture, and the EMG recorded from the lower intercostal space developed inspiratory activity during CPAP in head-up posture. All of 10 subjects felt most dyspneic during CPAP with the head-up. We conclude that the mechanism of increase in lung volume during CPAP is mediated by different pathway from that of posture change, and that CPAP in upright posture can alter the respiratory pattern of the subject.

Adult↗
PubMed1990

Interaction of sevoflurane, isoflurane, enflurane and halothane with non-depolarizing muscle relaxants and their prejunctional effects at the neuromuscular junction.

The interaction of four inhalational anesthetics (sevoflurane, isoflurane, enflurane and halothane) with pancuronium and vecuronium and also their prejunctional actions at the neuromuscular junction were quantitatively studied using rat phrenic nerve-hemidiaphragm preparations. To investigate the prejunctional effects of inhalational anesthetics, a train-of-four ratio (T4/T1) and the tetanus ratio (the ratio of the final response to the initial response during tetanus) were evaluated. All four inhalational anesthetics markedly potentiated the neuromuscular blockade of twitch response caused by either pancuronium or vecuronium with halothane and enflurane being the most potent both on a % concentration basis and on a MAC (minimum alveolar concentration) basis. Although none of the four inhalational anesthetics had any effects on the T4/T1 ratio, they produced variable effects on the tetanus ratio. Sevoflurane had little effect on the tetanus ratio, whereas 1 and 2% isoflurane and 1, 2 and 3% enflurane increased the tetanus ratio and 5% halothane and 5% enflurane significantly reduced the tetanus ratio. Halothane and enflurane had the most potent depressant action of the four inhalational anesthetics both on the % concentration basis and on the MAC basis. These results indicate that the main site of action of inhalational anesthetics is a postjunctional site at the neuromuscular junction and that they do not seem to act on prejunctional sites at the concentrations used in clinical situations.

Anesthetics↗
PubMed1990

Plastic injection method for preparing microvascular corrosion casts for SEM and its practical application.

This paper examines the application of the acryl plastic injection to the preparation of vascular corrosion microcasts for scanning electron microscopy (SEM). The original injection method using acryl plastic was described by Taniguchi, Ohta et al. in 1952 and 1955, under the title of "New improved method for injection of acrylic resin". Three dimensional observations were undertaken in our laboratory on the angiology at the macro- and microscopic levels of various organs from various mammals employing the original method. Based on this extensive experience, an injection method for preparing corrosion microcasts for use in SEM was devised in our laboratory. Microcasts prepared by the present method were able to demonstrate the fine vascular architecture of each organ. In general, although applications for preparing vascular microcasts of isolated and parenchymal organs are not so difficult, the method can be used to be applicable for demonstrating the fine vascular architecture related to or within hard tissues, as well as for investigating the morphological relations between changes of vascular patterns and restorative changes in the surrounding tissues affected by experimental operations. SEM microphotographs are also presented to illustrate actual practical applications.

Animals↗
PubMed1990

Microvascular architecture of the enamel organ of the upper major incisor in the rabbit.

The ultrastructure of the ameloblasts in the rabbit major incisor was investigated previously by Okada (1983) and the amelogenetic process was classified into six zones/stages. The present paper deals with changes in the microvascular architecture and ultrastructure of the blood capillaries in proportion to the amelogenetic process in the upper major incisor of the rabbit utilizing the acryl plastic injection method. Three different vascular layers were observed in the periodontal spaces of the major incisor of the rabbit. The inner vascular network consisted of a capillary network supplying the enamel organ and its meshes have vigorously changed during the amelogenesis. The capillary network was observed to be in the shape of a ladder with a continuous wall in the proliferation zone, to appear as round meshes with a fenestrated wall in the differentiation zone, as polygonal meshes with abundant fenestrations in the secretion zone, as ovoid meshes with fenestrations in the early maturation zone, and finally as coarse and avoid meshes with a continuous wall again in the late maturation and regression zones. In the intermediate layer, arterioles and venules were located close to the capillary network, and the arterioles were derived from the short and long branches of the anterior superior alveolar artery. In the outer layer, a sinusoid network was observed to be in contact with the alveolar wall and received blood from the capillary network as well as venous vessels in the alveolar bone. The ladder-shaped capillary network mentioned above was thought to represent an intermediate form towards the succeeding zone, in which the round meshes may be suitable for supplying the nutrient elements that are needed in the differentiation of the inner enamel epithelial cells. The polygonal and ovoid meshes may be favorable for the transport of various necessary metabolic materials that are involved in the enamel ground substance formation and calcium deposition within a very short period.

Acrylates↗
PubMed1990

Binding sites of interleukin-3-mimetic monoclonal autoantibodies derived from a MRL/lpr mouse.

MRL/lpr mouse-derived interleukin-3 (IL-3)-mimetic monoclonal antibodies were examined for their binding sites. One of these five antibodies (B10, F8, F9, F12, H11), F9 interacted with the IL-3 receptor, as if it were an anti-idiotypic antibody; the IL-3-mimetic activity of F9 was blocked by a neutralizing rat monoclonal anti-IL-3 antibody. IL-3 mRNA was not detected in hybridoma F9, as analyzed by the S1 protection assay, Thus, the activity neutralized by the rat antibody is of the F9 antibody itself but not the IL-3 type. Such blocking was not observed with the IL-3-mimetic activity of the other MRL/lpr-derived monoclonal antibodies. On the other hand, the binding of all these monoclonal antibodies to IL-3-dependent cells was inhibited by each other and vice versa, as analyzed by two-color flow cytometry. This indicates that the binding sites of the five monoclonal antibodies are located so close to each other that the binding of one would interfere with the binding of any one of the others (since the binding experiment was done on ice, it is unlikely that the inhibition is due to down-modulation of the receptors). Taken together the results obtained by the enzyme digestion study, we discussed that all five IL-3-mimetic monoclonal antibodies are directed to the IL-3 receptor, but only F9 binds to the portion directly responsible for the binding of IL-3 and the other antibodies (B10, F8, F12, H11) bind to different portions, respectively, which are adjacent or overlapping to the binding site of F9.

Animals↗
PubMed1990

Antimutagenicity and binding of lactic acid bacteria from a Chinese cheese to mutagenic pyrolyzates.

The microbiological characteristics of Nai Ge Da, a traditional cheese in China, was investigated. The lactic acid bacteria species were identified as Streptococcus cremoris, Streptococcus lactis ssp. diacetylactis, Streptococcus faecalis, and Leuconostoc paramesenteroides, Leuconostoc dextranicum, and Leuconostoc mesenteroides. Streptococcus cremoris, and Leuconostoc paramesenteroides were the dominant strains. The antimutagenicities and binding of strains of S. cremoris and S. lactic ssp. diacetylactis to mutagenic pyrolyzates was investigated. The lyophilized cells of strains showed the highest inhibitory effect on the 3-amino-1,4-dimethyl-[5H]pyrido[4,3-b] indol (Trp-P-1) and 3-amino-1-methyl-[5H]pyrido[4,3-b] indol (Trp-P-2), but many strains had no significant inhibition against 2-amino-6-methyldipyrido[1,2-a:3',2'-d] imidazole (Glu-P-1). The Trp-P-1 and Trp-P-2 were effectively bound to all bacterial cells, but binding of Glu-P-1 to cells was not effective. Among the strains tested, S. cremoris C-25 not only indicated highest binding to Trp-P-1 and Trp-P-2, but it also it had a 25.36% binding ability with Glu-P-1. When all strains were autoclaved for 15 min at 120 degrees C, binding ability to mutagens was reduced by 3 to 19%. The decrease of binding ability of S. cremoris C-25 was much less, being only 2%. After heating at 80 degrees C for 3 h, the binding ability of all strains to mutagenic pyrolyzates was not much different from those of parent viable cells.

Amino Acids↗
PubMed1990

[A case of hypopharyngeal stenosis caused by late radiation injuries--reconstruction of the hypopharynx with myomucosal tongue flap].

The authors reported a 47-year-old man with hypopharyngeal stenosis caused by late radiation injuries. At the age of ten he underwent irradiation (3000rads) to the neck because of the cervical lymphadenopathy. He had keroid skin change at the age of 19, hypothyroidism since 26, right cervical and brachial plexus neuropathy since 33, and paralysis and papilloma of right vocal cord at 34. And at the age of 41 he underwent tracheostomy owing to laryngeal stenosis. In November 1984 (at age 43) he felt abnormal sensation on the throat but had no dysphagia nor misdiglutition. On November 1987 he had difficulties of swallowing, and could not take anything but fluid. At that time he was diagnosed as hypopharyngeal stenosis. With steroids and antibiotics his difficulties of swallowing were reduced. He experienced the same difficulties on April 1988. Since December 1988 his dysphagia got worse and was not recovered with medication. On May 17 1989, laryngopharyngectomy was performed. At the level of cricoid cartilage hypopharynx was resected. As for the posterior wall, pharynx and cervical esophagus were fixed to prevertebral fascia and anastomosed with end-to-end. And antero-lateral defects were reconstructed with myomucosal tongue flap. Postoperatively he could eat orally. On the basis of the experience of this case and the review of the literature the authors conclude that myomucosal tongue flap is one of alternatives for hypopharyngeal reconstruction.

Constriction, Pathologic↗