Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 1,045 records · Page 58Linked to original sources

PubMed1992

Isoelectric point of an ion-penetrable membrane.

The surface potential of an ion-penetrable planar membrane is calculated for the case in which acidic and basic groups are present in the membrane. It is found that when both acidic and basic groups are not uniformly distributed in the direction normal to the membrane, the isoelectric point (the pH value at which the surface potential becomes zero) of the membrane varies with the electrolyte concentration, whereas if both groups are uniformly distributed, the isoelectric point is independent of the electrolyte concentration. As a simple example, we treat a membrane consisting of two layers, in which acidic groups are distributed in the outer layer and basic groups are in the inner layer. Simple equations determining the membrane surface potential as a function of pH and electrolyte concentration and the dependence of the isoelectric point on the electrolyte concentration are presented.

Chemical Phenomena↗

PubMed1992

Free radical formation induced by ultrasound and its biological implications.

The chemical effects of ultrasound in aqueous solutions are due to acoustic cavitation, which refers to the formation, growth, and collapse of small gas bubbles in liquids. The very high temperatures (several thousand K) and pressures (several hundred atmospheres) of collapsing gas bubbles lead to the thermal dissociation of water vapor into .OH radicals and .H atoms. Their formation has been confirmed by electron spin resonance (ESR) and spin trapping. The sonochemistry of aqueous solutions of gases and of volatile and nonvolatile solutes is reviewed. The similarities and differences between sonochemistry and radiation chemistry of aqueous solutions are explained. Some unusual characteristics of aqueous sonochemistry can be understood by considering the properties of supercritical water. By the use of rare gases with different thermal conductivities, it is possible to distinguish between temperature-dependent processes such as redox reactions initiated by .OH radicals and .H atoms and pressure-dependent processes which lead to polymer degradation and cell lysis. The evidence for free radical formation in aqueous solutions by pulsed ultrasound is discussed. This subject is of interest because it is related to the possible deleterious effects of ultrasonic diagnostic devices. The role of free radicals and of mechanical effects induced by ultrasound in DNA degradation, inactivation of enzymes, lipid peroxidation, and cell killing is reviewed.

Chemical Phenomena↗

PubMed1992

Effects of zonisamide on extracellular levels of monoamine and its metabolite, and on Ca2+ dependent dopamine release.

The effects of zonisamide (3-sulfamoylmethyl-1,2-benzisoxazole), a novel anticonvulsant, on extracellular levels of monoamine and its metabolite in the striatum and hippocampus, and Ca2+ dependent monoamine release in the striatum of freely moving rats were studied by microdialysis. Zonisamide increased dopamine, homovanillic acid and 5-hydroxyindoleacetic acid, and decreased 3,4-dihydroxyphenylacetic acid in the rat striatum. However, zonisamide showed no effect on Ca2+ dependent dopamine release in the rat striatum. In the hippocampus, zonisamide increased dopamine, homovanillic acid, serotonin and 5-hydroxyindoleacetic acid and decreased 3,4-dihydroxyphenylacetic acid. The present results suggest that zonisamide facilitates dopaminergic and serotoninergic neurotransmission but does not affect Ca2+ dependent dopamine release within therapeutic plasma concentrations.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1992

Interferon and natural killer cell activity in patients with exanthem subitum.

Early immune response was studied by assessing interferon (IFN) and natural killer cell activity in 13 patients with exanthem subitum associated with human herpesvirus 6 infection during the acute and convalescent phases. Only IFN-alpha showed a significant increase in the plasma of patients during the acute febrile phase compared with the convalescent period. The inhibitory effect of IFN-alpha and IFN-beta on human herpesvirus 6 replication was demonstrated in vitro with cord blood mononuclear cells. Natural killer cell activity was also significantly augmented in the acute phase, especially in the exanthem period, rather than in the convalescent phase (P less than 0.01). These results suggest that the enhanced IFN-alpha response and natural killer cell activity in the acute early phase of the disease may play pivotal roles in the recovery from exanthem subitum.

Cytotoxicity, Immunologic↗

PubMed1992

Human T cell leukaemia virus type 1 p21X mRNA: constitutive expression in peripheral blood mononuclear cells of patients with adult T cell leukaemia.

Although the p21X protein of human T cell leukaemia virus type 1 (HTLV-1) is generally thought to be expressed from a doubly spliced mRNA transcript (tax/rex mRNA) that encodes the p40tax, p27rex and p21X proteins, we have shown previously that a novel, alternatively spliced mRNA transcript (p21X mRNA) is responsible for p21X production in HTLV-1-infected cell lines. In the present study, we analysed expression of p21X mRNA and tax/rex mRNA in uncultured and cultured peripheral blood mononuclear cells (PBMCs) from eight patients with adult T cell leukaemia by using a quantitative polymerase chain reaction coupled to reverse transcription. The results demonstrated that the expression of p21X mRNA occurs constitutively in all uncultured and cultured PBMCs, whereas the expression of tax/rex mRNA is inducible in the cultured PBMCs, as described previously. In uncultured and cultured PBMCs from the one specimen in which p21X mRNA was highly expressed, the p21X protein was detectable by Western blotting. On the other hand, p27rex protein was detectable only after cultivation. These findings indicate that p21X mRNA is constitutively expressed in vivo and is responsible for production of p21X protein.

Adult↗

PubMed1992

Simultaneous establishment of myeloid and B-lymphoid cell lines with identical chromosome abnormalities from Philadelphia chromosome-positive chronic myelogenous leukaemia.

Two continuously growing cell lines, designated YOS-M and YOS-B, were established simultaneously from a patient with Philadelphia (Ph1) chromosome-positive chronic myelogenous leukaemia (CML) in myeloid blast crisis. Both YOS-M and YOS-B had the Ph1 chromosome and identical additional chromosome abnormalities, which were not detected in the chronic phase. Cytochemical analysis showed that YOS-M was significantly positive for peroxidase, whereas YOS-B was entirely negative. YOS-M expressed myeloid-associated antigens (CD14, CD33) as well as CD4, CD25 and CD34. The surface phenotype of YOS-M was identical to that of the leukaemic blasts found in the patient. On the other hand, YOS-B expressed mature B-cell markers, CD19, CD20, CD21 and surface immunoglobulin, but not myeloid-associated antigens. These two cell lines showed an identical rearrangement pattern of the break point cluster region on chromosome 22, but rearrangement of the immunoglobulin heavy chain gene was detected only in YOS-B. These findings provide definite evidence that CML cells still have the capability to differentiate and mature along different haematopoietic cell lineages even after blast crisis.

Aged↗

PubMed1992

Human herpesvirus 6 (HHV-6) infection in the central nervous system.

Human herpesvirus 6 (HHV 6) was isolated from patients with exanthema subitum (ES) with a high frequency, and it is now believed that this virus causes ES as a primary infection in childhood. HHV 6 infection is highly prevalent in early childhood and this virus may infect infants through the saliva mainly from mother to child. HHV 6 has a tropism to CD4+ cells and destroys cells in vitro. Although children recover from ES without any sequelae, neurological symptoms associated with exanthema subitum are often observed, and we could detect HHV 6 in the cerebrospinal fluid of ES patients. This result suggests that HHV 6 may invade the central nervous system and cause neurological symptoms.

Antibodies, Viral↗

PubMed1992

Epidemiology of neonatal chronic lung disease in Japan.

A nationwide survey on the epidemiology of chronic lung disease (CLD) of the newborn was conducted. Questionnaires were sent to 391 level II and III neonatal centers in Japan and the registration of infants born in 1990 with chronic lung disease was requested. CLD was defined as an oxygen requirement greater than that obtainable in room air at 28 days after birth, with symptoms of persistent respiratory distress and a hazy or emphysematous and fibrous appearance on chest X-ray. A total of 301 neonatal centers (77.0%) responded and 50,290 infants at these centers were registered. Of these, 97% survived the first month and 1,135 of 48,762 neonatal survivors developed CLD. The mortality of infants with CLD was 6.2%. Survival rates at 28 days of age increased consistently with birthweight. Survival at 28 days of age in infants below 1,000 g at birth was 73.7%, but the rate was 93.9% in infants weighing 1,000-1,499 g. The incidence of CLD was inversely proportional to birthweight. Approximately one quarter of neonatal survivors with a birthweight below 1,500 g and approximately half of extremely small infants ( < 1,000 g) developed CLD. The analysis of CLD infants showed that 28.2% of them had a history of respiratory distress syndrome (RDS) and a typical fibrous appearance on chest X-ray (Type I), while 29.3% also had a history of RDS but had an atypical X-ray appearance (Type II).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗

PubMed1992

In vivo recording of electrical activity of canine tracheal smooth muscle.

Electrical activity of the tracheal smooth muscle was studied using extracellular bipolar electrodes in 37 decerebrate, paralyzed, and mechanically ventilated dogs. A spontaneous oscillatory potential that consisted of a slow sinusoidal wave of 0.57 +/- 0.13 (SD) Hz mean frequency but lacked a fast spike component was recorded from 15 dogs. Lung collapse accomplished by bilateral pneumothoraxes evoked or augmented the slow potentials that were associated with an increase in tracheal muscle contraction in 26 dogs. This suggests that the inputs from the airway mechanoreceptors reflexly activate the tracheal smooth muscle cells. Bilateral vagal transection abolished both the spontaneous and the reflexly evoked slow waves and provided relaxation of the tracheal smooth muscle. Electrical stimulation of the distal nerve with a train pulse (0.5 ms, 1-30 Hz) evoked slow-wave oscillatory potentials accompanied by a contraction of the tracheal smooth muscle in all the experimental animals. Our observations in this in vivo study confirm that the electrical activity of tracheal smooth muscle consists of slow oscillatory potentials and that tracheal contraction is at least partly coupled to the slow-wave activity of the smooth muscle.

Action Potentials↗

PubMed1992

Relationship between plasma levels of hyaluronic acid and amyloid-associated osteoarthropathy in chronic hemodialysis patients.

Plasma levels of hyaluronic acid (HA) and acute-phase reactants were determined in chronic hemodialysis patients with or without carpal tunnel syndrome (CTS) and/or shoulder pain, which are characteristic symptoms of amyloid-associated osteoarthropathy. While levels of acute-phase reactants tended to be higher in the patients with CTS and/or shoulder pain than in patients without these symptoms, the difference was not significant. However, plasma levels of HA were significantly higher in the patients with these symptoms. Analysis of plasma levels of HA in age-matched patients also demonstrated a significant correlation between elevated levels of HA and the presence of CTS and/or shoulder pain. Among the patients with CTS and/or shoulder pain, those patients with bone cysts in the carpal bone or humeral head had significantly higher plasma levels of HA than patients without bone cysts. Thus, there appears to be a relationship between elevated plasma HA and amyloid-associated osteoarthropathy in chronic hemodialysis patients that is more specific than any correlation with levels of acute-phase reactants.

Acute-Phase Proteins↗

PubMed1992

Adult T cell leukemia associated with eosinophilia: analysis of eosinophil-stimulating factors produced by leukemic cells.

The mechanism of eosinophilia in a patient with adult T cell leukemia (ATL) was investigated. A 61-year-old woman with ATL presented marked eosinophilia. No parasite infections or allergic diseases were found in this patient. The number of eosinophils fluctuated in parallel with that of ATL cells during her clinical course. The patient's serum and the culture supernatant of ATL cells showed eosinophil colony-stimulating activity. Northern blot analysis of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and interleukin-5 (IL-5), which are known eosinophil CSFs, showed that only GM-CSF but not IL-3 or IL-5 was expressed in freshly separated and cultured ATL cells. Since neutrophil and monocyte numbers did not increase, it is suggested that GM-CSF and unknown cytokines other than IL-3 and IL-5 produced by ATL cells synergistically stimulated eosinophil precursors in the present case.

Blotting, Northern↗

PubMed1992

An interpretation of cell separation mechanism on polyamine graft copolymers.

Interaction between polyamide microcapsules having different balances of negative and positive charges on their surface, that is, different isoelectric points and copolymers with different numbers of polyamine macromer of a definite chain length grafted on poly(2-hydroxyethyl methacrylate) backbone was studied by measuring the amount adhered of the microcapsules onto the surface of copolymer-coated glass beads at different pH values. Maximum microcapsule adhesion was observed for a proper combination of microcapsule and copolymer to suggest that separation of a specified cell population from others on the surface of copolymer-coated glass beads can be explained in terms of preferential adhesion through electrostatic interaction of the specified cells with the copolymer.

Cell Separation↗

PubMed1992

A light and electron microscopic anterograde WGA-HRP tracing study on the sensory innervation of junctional and sulcular epithelium in the rat molar.

The sensory innervation of junctional and oral sulcular epithelium was investigated by use of anterograde transport of wheat-germ agglutinin-horseradish peroxidase from the trigeminal ganglion. By light microscopy, labeled intra-epithelial nerve fibers were observed forming a dense plexus in the apical two-thirds of the junctional epithelium, with some fibers located near the enamel space. Occasional fibers extended coronally to the sulcus bottom. By electron microscopy, labeled intra-epithelial axon terminals or varicosities were demonstrated to be in close contact with both junctional epithelial cells and neutrophils. These varicosities, which were occasionally surrounded by the cytoplasmic processes of epithelial cells or neutrophils, frequently contained large granular and small clear vesicles. In contrast to the junctional epithelium, the oral sulcular epithelium was sparsely innervated, except for the transition region between the oral sulcular epithelium and the junctional epithelium, where a dense innervation by labeled intraepithelial fibers was found. These fibers extended as far as the stratum spinosum. Electron microscopy revealed mitochondria-filled profiles of varicosities between epithelial cells. This study shows differences in the distribution and ultrastructure of sensory nerves between the junctional and oral sulcular epithelia, and further provides morphological evidence that sensory nerves in the junctional epithelium come into contact not only with epithelial cells but also with neutrophils.

Animals↗

PubMed1992

Light pulses induce "singular" behavior and shorten the period of the circadian phototaxis rhythm in the CW15 strain of Chlamydomonas.

While measuring action spectra for phase-shifting the circadian clock of Chlamydomonas, we observed that light pulses started near the phase response curve (PRC) "breakpoint" caused a reduction of the amplitude of the phototactic rhythm and two unexpected effects: (1) nonmonotonic fluence response curves (FRCs), and (2) shortening of the period of the subsequent free-running rhythm. The reduction of the rhythm's amplitude is dependent upon both the fluence and wavelength of the light pulse. The results are consistent with the amplitude being dependent upon the perceived "strength" of the stimulus, and with the nonmonotonic FRCs and reduced amplitude reflecting a light-induced change of the pacemaker's state variables to a region of the phase plane close to the "singularity." The period change that is evoked by single stimuli exhibits novel characteristics: large changes in period and a phase specificity that correlates with "singular" behavior. These period changes also appear to be a function of the stimulus strength, but indirectly; the magnitude of the period change is most strongly correlated with the magnitude of the light-induced phase shift. These results are interpreted in the context of limit cycle models of circadian clocks, and are used to suggest new tactics for measuring action spectra of light-induced clock resetting.

Animals↗

PubMed1992

Ganglioside composition and its relation to clinical data in brain tumors.

The ganglioside composition of 15 cases of meningioma, 15 cases of astrocytoma, 5 cases of neurinoma, 4 cases of ependymoma, 3 cases of metastatic brain tumor and 1 case each of mixed glioma, oligodendroglioma, medulloblastoma, embryonal carcinoma, and cultured glioma cell line were analyzed by thin-layer chromatography. The GM2, GD3, and GD2 content of the tumors was determined using specific monoclonal antibodies (MAb). Cases were grouped according to the difference in ganglioside pattern and various clinical features. In meningiomas and astrocytomas, GM3 and GD3 were the major gangliosides. The tumor content of the rather simple gangliosides (GM3, GM2, GD3, GD2) increased or was almost equal to that of normal tissue (leptomeninges tissue in the case of meningiomas, and brain tissue in the case of astrocytomas), while the tumor content of complex gangliosides (GM1, GD1a, GT1a, GT1b) decreased as compared with normal tissue. The GM3 content of meningiomas increased in middle-aged patients, who comprised the majority of the patients with these tumors. The GD2 content decreased in middle-aged patients with initial symptoms of meningioma within a year. The GM3 content of astrocytomas decreased in patients who underwent radiotherapy. The amount of GM3 and GD3 increased in small tumors. GM3 may be related to the early proliferative stage. The ganglioside patterns of brain tumors are shown in this study to differ according to clinical features and also to be changeable in their clinical courses.

Aging↗

PubMed1992

Radiotherapy for pediatric brain stem glioma: radiation dose, response, and survival.

An analysis of 39 patients under 20 years of age with brain stem glioma treated with radiotherapy between 1977 and 1991 was undertaken. Twenty-eight (71.2%) of the patients responded well to initial radiotherapy, and 11 (28.8%) responded poorly. Median survival for the total patient population was 10 months. Response rates and median survivals were influenced by radiation dose: 45.5% and 9 months at doses less than 4499 cGy (n = 11), 83.3% and 13 months at doses between 4500 and 5499 cGy (n = 12), 66.7% and 11.5 months at doses between 5500 and 6499 cGy (n = 9), and 100% and 10 months at doses more than 6500 cGy (n = 7). Multivariate analysis revealed the response to initial radiotherapy was the only predictor of survival with radiation doses up to 6499 cGy. Four of the patients who responded well demonstrated radiological and/or histological calcification within or around the tumor at the time of clinical deterioration. Radiation injury was confirmed in two autopsy cases. The possibility that intratumoral radiation injury causes clinical deterioration is suggested.

Adolescent↗

PubMed1992

[Use of water-soluble beta-cyclodextrin derivatives as carriers of anti-inflammatory drug biphenylylacetic acid in rectal delivery].

To improve the rectal delivery of an anti-inflammatory drug, biphenylylacetic acid (BPAA), the use of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and heptakis (2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) was investigated. Inclusion complex formations of BPAA with both beta-CyDs in a molar ratio of 1:1 in water were ascertained, and their stability constants were determined. The dissolution of BPAA in water and the release of BPAA from an oleaginous suppository (Witepsol H-5) were significantly increased by beta-CyDs, depending on the magnitude of the stability constants of the water-soluble complexes. However, the serum levels of BPAA after rectal administration of the suppositories containing BPAA or its beta-CyDs complexes in rats increased in the order of BPAA alone much less than DM-beta-CyD less than or equal to HP-beta-CyD complex. The in situ recirculation study revealed that the greater the stability constant of the complex, the lesser was the absorption of BPAA from the rectal lumen of rats under the solution state. Both in vivo and in situ studies demonstrated that rather high amount of HP-beta-CyD (about 20% of dose) was absorbable from the rat's rectum, compared with DM-beta-CyD (less than 5% of dose), suggesting the possibility of the permeation of BPAA through the rectal membrane in the form of HP-beta-CyD complex. Furthermore, DM-beta-CyD and HP-beta-CyD significantly reduced the irritation of the rectal mucosa caused by BPAA after the administration of the suppositories to rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Rectal↗

PubMed1992

Evaluation of cardiac motion and function by cine magnetic resonance imaging.

Cardiac cine magnetic resonance imaging (MRI) was studied to evaluated the cardiac motion and function, and a water-stream phantom study was performed to clarify whether it was possible to quantitatively assess the valvular regurgitation flow by the size of the flow void. In normal subjects, the left ventricular (LV) epicardial apex swung up to the base only a few millimeters, and the mitral annulus ring moved about 14 mm as mean value toward the apex during systole. Those motions of mitral annulus ring may contribute to the left atrial filling. The LV longitudinal shortening and torsions were shown by the tagging method. This tagging method was the best method for estimating cardiac motions. Cardiac cine MRI using software including a modified Simpson's method program and a wall motion analysis program was useful for routine LV volumetry and wall motion analysis because it was a simple and reliable method. Our water-stream phantom studies demonstrated that it might be difficult to perform quantitative evaluation of valvular regurgitation flow by using only the size of the flow void without acquiring information relating to the orifice area.

Adult↗