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Biomedical subjects

Y Kubo

Publications and source records attributed to Y Kubo.

At least 271 records · Page 15Linked to original sources
PubMed1992

[Nd-YAG laser treatment of tracheo-bronchial stenotic lesions].

Fourteen patients were treated with a Nd-YAG laser. Treatment to relieve airway stenosis was administered on fifteen occasions, and on one occasion to treat an obstruction. In each case the flexible fiberoptic bronchoscope was used. In 4 emergency cases, three involving tracheal lesions and one involving a bronchial lesion, the airway was widened and the patients' condition was improved after laser ablation. In the palliative treatment of 12 lesions, the stenoses were severed and treated at an interval of time varying between one and three weeks. Complications occurred in 3 cases. There were 2 instances of massive haemorrhage and one of pneumothorax which occurred while treating the 5 stenoses situated at broncho-plastic anastomoses.

Adult↗
PubMed1991

Detection and quantitative estimation of metalloporphyrins in vivo.

Spectrofluorometry, radioisotope (RI) labelling and high performance liquid chromatography (HPLC) can be used to estimate photosensitizer concentrations. The biodistribution of porphyrins and metalloporphyrins containing the bifunctional chelating agent diethylenetriamine pentaacetic acid (DTPA) was examined in tumour-bearing mice by nitrogen-pulsed laser spectrofluorometry (PLS) and RI labelling. The biodistribution of metalloporphyrin amino acid derivatives containing alkoxyl groups was also examined by PLS and HPLC analysis using an acetone powder extraction method. Spectrofluorometry is useful for estimating the biodistribution of porphyrins in tumour, lung, kidney and serum, but not in liver. However, spectrofluorometry cannot be used to evaluate the concentration of certain metalloporphyrins such as manganese complexes. The concentrations of porphyrins in liver measured by PLS and two other methods showed remarkable differences. RI labelling and HPLC analysis are obviously tedious methods. Therefore it seems practical to screen for a number of compounds using the spectrofluorometric method (PLS). Subsequently, the porphyrins which give good results with PLS should be measured using RI labelling and HPLC.

Animals↗
PubMed1991

Properties of ionic currents induced by external ATP in a mouse mesodermal stem cell line.

1. ATP was puff applied to cells of a mesodermal stem cell line, C3H10T1/2, and the responses were studied by whole-cell patch clamp recording. 2. In 91% of the cells (90/99), K+ current lasting for tens of seconds was observed after several seconds latency. The current showed outward rectification. In 10% of the cells (9/99), ATP induced Cl- current which also lasted for tens of seconds after several seconds latency, but showed little rectification. In 6% of these cells (5/99), both K+ and Cl- currents were induced by ATP. 3. The K+ current induced by ATP was dose dependent, with a Kd of 0.4 microM. The effects of ATP analogues were tested at a concentration of 20 microM. ADP and ATP-gamma-S induced the K+ current, while AMP and adenosine did not. alpha, beta-Methylene ATP produced a diminished K+ current. 4. The ATP-induced K+ current was not observed when EGTA in the internal solution was raised from 0.1 to 5 mM. In Fluo-3-loaded cells, an increase in intracellular Ca2+ concentration induced by the application of ATP was observed, and the time course was similar to the induced K+ current. Both the increase in intracellular Ca2+ and the K+ current were induced by ATP even in Ca(2+)-free external solution. Ryanodine (50 microM) in the external solution did not affect the ATP response, and application of 10 mM-caffeine alone to the external solution did not induce any response. 5. The variance of the steady-state fluctuations in the course of the ATP-induced slow K+ current was analysed. The single-channel conductance was estimated as 2.7 pS at 0 mV with external and internal K+ concentrations of 5 and 140 mM respectively. The K+ current was not affected by apamin at concentrations of up to 1 microM but was reduced to one-third by 140 mM-tetraethylammonium (TEA). 6. It was concluded that puff-applied ATP has two main effects in the mesodermal stem cells: an increase in the intracellular Ca2+ concentration and a succeeding hyperpolarization due to the Ca(2+)-activated K+ conductance which is present in this cell. The significance of the increase in intracellular Ca2+ caused by ATP is discussed.

Adenosine Triphosphate↗
PubMed1991

Electrophysiological and immunohistochemical analysis of muscle differentiation in a mouse mesodermal stem cell line.

1. A mesodermal stem cell line C3H10T1/2 was induced to differentiate to muscle by adding 0.3 microM-5-aza-2'-deoxy-cytidine to the medium for 24 h. The changes in membrane currents during differentiation were studied by whole-cell recording and changes in the expression of fibronectin, Neural Cell Adhesion Molecule (NCAM), myosin and desmin were studied immunohistochemically. 2. The stem cells showed the morphology of fibroblastic cells. Most of the stem cells showed ATP-induced slow K+ current. T-type Ca2+ current and inward rectifier K+ current were observed in 19% of the stem cells. The stem cells expressed fibronectin, but not NCAM, myosin or desmin. 3. About 2 weeks after the addition of 5-aza-2'-deoxy-cytidine, large multinucleated skeletal muscle-like cells appeared. Most of the induced muscles showed L-type Ca2+ current, responses to acetylcholine, outward K+ current, inward rectifier K+ current and contraction upon depolarizing stimulation. They expressed NCAM, myosin and desmin, but not fibronectin, and showed no ATP response. 4. In some batches (2/14), the induced muscles showed spontaneous twitches, and possessed tetrodotoxin (TTX)-sensitive Na+ current in addition to the currents described above. Furthermore clear striation was observed in some of the twitching muscles under Nomarski optics. 5. To ascertain the properties of cells at the initial step of muscle differentiation, whose differentiation is determined but not yet evident morphologically or electrophysiologically, subcloning was performed from the heterogeneous cells 10 days after induction. Three myogenic clones were obtained, which proliferated at low cell densities but differentiated to muscle with a high incidence at high cell densities, as well as ten non-myogenic clones. 6. Most myogenic clones still showed ATP-induced K+ current and fibronectin. In addition, most of them showed T-type Ca2+ current and inward rectifier K+ current. They had already expressed NCAM. No other properties observed in muscles had yet been expressed. Most cells of the non-myogenic clones showed ATP-induced K+ current and fibronectin. T-type Ca2+ current was also expressed, but not inward rectifier K+ current or NCAM. 7. The properties of the observed ionic currents were studied. The TTX-sensitive Na+ current could be completely blocked by 0.1 microM-TTX. It could be evoked by depolarizing steps to a level above -40 mV, while steady-state inactivation was detectable around -75 mV and reached half by -52 mV. T-type Ca2+ current could be evoked by a depolarizing pulse to a level above -45 mV, with a maximum amplitude around -15 mV.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Comparison of initial stages of muscle differentiation in rat and mouse myoblastic and mouse mesodermal stem cell lines.

1. Electrophysiological and immunohistochemical properties during the early stages of muscle differentiation were studied in two myoblastic cell lines, mouse C2C12 and rat L6, and compared to those in myogenic clonal cells derived from the mouse mesodermal stem cell line C3H10T1/2, studied in the preceding paper. 2. Mouse C2C12 cells were induced to differentiate to muscle by changing from 10% fetal calf serum to 2% horse serum in the medium. Most of the C2C12 cells before serum reduction showed ATP-induced slow K+ current. Twelve per cent showed inward rectifier K+ current. They expressed fibronectin and Neural Cell Adhesion Molecule (NCAM). Small spindle-shaped cells at an early stage of muscle differentiation began to appear 24 h after serum reduction. In contrast to cells before serum reduction, only 13% of these spindle-shaped cells showed an ATP response. Most showed tetrodotoxin (TTX)-resistant Na+ current and outward K+ current. Thirty-eight per cent had inward rectifier K+ current. They expressed NCAM but not fibronectin. The T-type Ca2+ current was not observed up to the latest stage of differentiation investigated. 3. Rat L6 cells in maintaining culture medium showed only infrequent ATP responses, but already showed TTX-resistant Na+ current. No clear T-type Ca2+, inward rectifier K+ or outward K+ currents were observed. About one-third of the cells did not express fibronectin. From these results, L6 cells appear to be at a stage near to but slightly earlier than that of C2C12 cells after serum reduction. 4. The properties of the early stages of muscle differentiation in C3H10T1/2 cells, such as the disappearance of ATP-induced K+ current and fibronectin, and the appearance of NCAM, were also seen in C2C12 and L6. However, T-type Ca2+ and inward K+ currents, which were found in the initial stages of C3H10T1/2 muscle differentiation, were not clearly observed in C2C12 and L6. Instead, C2C12 and L6 showed a TTX-resistant Na+ current which was never observed in C3H10T1/2 cells. 5. The properties of the TTX-resistant Na+ current were investigated. In L6 cells, it was reduced to 60% by 1 microM-TTX. It could be evoked by depolarizations to a level above -50 mV with a maximum amplitude at around -15 mV. Steady-state inactivation was detectable with pre-pulses to -100 mV for 100 ms and reached half at pre-pulses of -78 mV. These parameters of inactivation are clearly different from those of the TTX-sensitive Na+ current observed in C3H10T1/2-derived mature muscle cells in the preceding paper.

Animals↗
PubMed1991

[A case of asymptomatic paraganglioma diagnosed by abnormal shadow on chest X-ray].

A 65-year-old man was noted to have an abnormal shadow on chest X-ray at mass screening examination, and was seen at Douhoku Byoin National Sanatorium. Chest X-ray showed a homogeneous mass shadow and a lytic lesion of the right 5th rib with extra-pleural tumor sign at the right upper and middle lung fields. Retroperitoneal tumor of 5 cm in diameter was detected in the right adrenal area by ultrasonography. Because of increasing plasma levels of norepinephrine and dopamine, the diagnosis of malignant pheochromocytoma with rib metastasis was made. Histologically, chromogranin staining was positive in each resected specimen. The retroperitoneal tumor was separate from the right adrenal gland. We report a rare case of malignant paraganglioma which was asymptomatic in spite of increasing plasma levels of catecholamines.

Aged↗
PubMed1990

Hepatitis C viral cDNA clones isolated from a healthy carrier donor implicated in post-transfusion non-A, non-B hepatitis.

Using a specific hepatitis C virus (HCV) antibody assay, positive blood donors responsible for the transmission of post-transfusion non-A, non-B hepatitis (PT-NANBH) were identified. cDNA fragments were isolated from one of the plasma samples of such healthy HCV carriers by using polymerase chain reactions. Nucleotide (nt) sequence analyses of the cDNA from three different regions of the viral genome revealed that they were derived from a Japanese HCV isolate that was similar but not identical to the prototype HCV previously isolated from a chronically infected chimpanzee. Homology at the nt and amino acid levels was comparatively lower in the presumed structural region than in putative nonstructural regions. This result not only confirms that HCV antibody-positive blood contains infectious HCV, but suggests the existence of different type(s) of HCV.

Amino Acid Sequence↗
PubMed1990

Bone mineral analysis and X-ray examination of the bone in patients with biliary atresia.

Investigations of bone mineral content, X-ray of the radius and ulna and serum biochemical analysis were performed in 10 children with biliary atresia (B.A.) and 150 healthy children. The patients were classified into 2 groups, namely; group A, comprised of 5 patients whose postoperative courses went well, and group B, comprised of 5 patients who developed various degrees of liver disturbance postoperatively. The ratio of bone mineral content (BMC) to bone width (BW) (BMC/BW) increased in accordance with age in the healthy children and the patients of group A, but was relatively slow in the patients of group B. Signs of rickets were found on the X-rays of 4 of the 10 patients, while serum levels of calcium and 25-OH-vitamin D in the group B patients were significantly lower than those in the group A patients or healthy children. Serum levels of alkaline phosphatase (Alp) fluctuated, but serum Alp was elevated in all the patients with rickets.

Age Determination by Skeleton↗
PubMed1990

CT simulator: a new 3-D planning and simulating system for radiotherapy: Part 1. Description of system.

A real time CT-linked 3-D treatment planning system, called a CT simulator, has been developed. The basic system consists of a CT scanner, a multi-image display component, a treatment planning device with real time visual optimization, and a laser beam projecting component. All the components are connected on line. The system can be conveniently used for 3-D planning and simulation for radiation therapy within a reasonably short period of time.

Computer Simulation↗
PubMed1990

CT simulator: a new 3-D planning and simulating system for radiotherapy: Part 2. Clinical application.

We have performed radiotherapy treatment planning (RTP) with a new system called CT simulator in 72 patients. With the system, RTP is performed with the patient lying on the CT couch within a short period of time. All the CT images scanned were immediately transported to the multi-image monitors and to the treatment planning device. Radiotherapy treatment planning could be performed not only at the beam center but also at any CT slice. Using a laser-beam field projector, field outlines were drawn over the patient's skin. In clinical use, the system was useful for cases in which a target lies adjacent to dose limiting organs, cases with a complicated target shape, cases with complicated dose distribution curves, and cases treated with tangential fields. This system enables us to make optimum use of CT information and to make accurate 3-dimensional treatment planning programs.

Computer Simulation↗
PubMed1990

The tumour-localizing properties of porphyrin derivatives.

The tumour-localizing abilities of various kinds of porphyrin derivatives in tumour-bearing hamsters were assessed by nitrogen-pulsed laser spectrofluorometry (N2-PLS). On examination of porphine derivatives (from haemoglobin), it was found that the dimer and acetylated and amidated compounds had a high affinity for tumour tissue; the dimer and hydroxylated compound of phorbine derivatives (from chlorophyll) also showed a high affinity. Furthermore, of the metalloporphines (gallium, zinc and indium complexes), those which contained hydrophilic groups showed a high affinity for tumour tissue; of the metallophorbines (gallium, zinc and indium complexes), those which contained hydrophobic groups showed a high affinity. A correlation was found between the side-chain structure of the porphyrins and metalloporphyrins and their affinity for tumour tissue.

Animals↗
PubMed1990

The putative nucleocapsid and envelope protein genes of hepatitis C virus determined by comparison of the nucleotide sequences of two isolates derived from an experimentally infected chimpanzee and healthy human carriers.

cDNA fragments of a 5'-terminal region of the hepatitis C virus (HCV) genome were isolated by the reverse polymerase chain reaction from RNA extracted from plasma samples of healthy Japanese carriers. Their nucleotide sequence was compared with that of the original isolate which had been passaged twice in chimpanzees. No deletions or insertions were observed between the two sequences in the regions examined. Both the 5' untranslated and putative nucleocapsid (core) protein regions were highly conserved (99% and 91% nucleotide identities, respectively). In contrast, the region immediately downstream which encodes a putative envelope glycoprotein(s) showed only 74% nucleotide identity between the two isolates. At the polypeptide level, the core and envelope domains showed 97% and 75% amino acid identities, respectively. This envelope variation may reflect the adaptation of HCV to the different hosts and/or the result of immunological selection. The highly conserved nucleotide sequence of the 5' untranslated and core regions may play an important regulatory role in the life cycle of HCV.

Amino Acid Sequence↗
PubMed1990

Treatment of experimental tumors with a combination of a pulsing magnetic field and an antitumor drug.

We investigated the effects of a combination treatment involving a pulsing magnetic field (PMF) and an antitumor drug, mitomycin C (MMC), on two experimental tumors (fibrosarcoma KMT-17 and hepatocellular carcinoma KDH-8) in WKA rats, paying attention to possible potentiation of the therapeutic effect of the antitumor drug. PMF was obtained using a system generating a pulsed current in a solenoid coil. On day 7 after tumor implantation into the right thighs of rats, the region of the tumor was exposed to PMF (frequency 200 Hz, mean magnetic flux density 40 gauss) for 1 h immediately after iv injection of MMC at a dose of 1 mg/kg. Survival rates at day 90 of KMT-17 implanted rats were 0% (0/10) in the non-treated group, 34% (4/12) in the MMC-treated group, 47% (6/13) in the PMF-treated group and 77% (10/13) in the MMC/PMF combination group. The increase of life span (ILS) of KDH-8-implanted rats in the combination therapy group was significantly prolonged (%ILS 17.6%) compared with that in the MMC-treated (%ILS 3.4%) and PMF-treated (%ILS 7.6%) groups. By using cultured cells of the above two lines of tumor, the therapeutic effects of MMC and PMF were also determined from the cell colony-forming efficiency in soft agar. The colony-forming efficiencies of both cell lines were significantly suppressed in the combination therapy group compared with those in the other single therapy groups. The present results indicate that PMF exhibited a potentiation of the antitumor effect of mitomycin C.

Animals↗