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Biomedical subjects

K Hirose

Publications and source records attributed to K Hirose.

At least 289 records · Page 16Linked to original sources
PubMed1993

Molecular cloning of polymorphic markers on RLGS gel using the spot target cloning method.

A new method for target cloning of DNA fragments corresponding to spots on the two-dimensional restriction landmark genomic scanning (RLGS) profile has been developed (targeted spot cloning). We used a Not I restriction trapper to select target DNA fragments from Not I, Eco RV double digests of genomic DNA. The use of the restriction trapper substantially reduces the background clones that are established from the direct recovery of RLGS spot DNA from the two-dimensional gels. Genomic DNA clones were isolated in this study as mouse genome markers for 58 spot loci that were previously characterized using RLGS spot mapping. This method provides a powerful tool for isolating DNA clones after their identification by RLGS system.

Animals↗
PubMed1993

Caffeine inhibits Ca(2+)-mediated potentiation of inositol 1,4,5-trisphosphate-induced Ca2+ release in permeabilized vascular smooth muscle cells.

We studied the effects of caffeine on inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release in saponin-permeabilized smooth muscle cells. The Ca2+ concentration in the vicinity of the Ca2+ store was strongly buffered to exclude the secondary effect of Ca2+ on the Ca2+ release. 2 mM caffeine shifted the IP3 concentration-Ca2+ release relation at 100 nM Ca2+ to the higher IP3 concentration without decreasing the steepness of the relation. The ascending limb of the biphasic Ca2+ dependence of IP3-induced Ca2+ release was shifted to the higher Ca2+ concentration by 2 mM caffeine. However, caffeine showed little inhibitory effect in the absence of Ca2+. These results indicate that caffeine inhibits IP3-induced Ca2+ release only when the Ca2+ release is potentiated by Ca2+.

Animals↗
PubMed1993

Structure and function of the intracellular portion of the mouse interleukin 1 receptor (type I). Determining the essential region for transducing signals to activate the interleukin 8 gene.

The structural and functional relationships of the intracellular portion of mouse interleukin 1 receptor (muIL-1R) type I were examined with regard to activation of the human IL-8 gene in the Jurkat T cell line. C-terminal deletion mutations of muIL-1R revealed that the C-terminal boundary for receptor function is localized between 28 and 42 amino acids from the C-terminal end. The internal deletion mutants between amino acids 364 and 474 had a loss of activity, demonstrating the requirement for a large region of the mIL-1R cytoplasmic portion for receptor function. Amino acid substitution revealed that the putative nuclear localization elements (amino acids at 429-433, 523-527, and 507-519) and putative protein kinase C or A acceptor sites (Ser-431, Ser-509, Ser-528) do not participate in IL-1 signaling to induce IL-8 gene expression. A truncated mutation within the segment, which possesses homology with gp130, beta chain of IL-6R, or a point mutation of box 1- and box 2-like elements within the gp130 homologous segment, abolished the capacity to induce IL-8 gene expression, suggesting similar structural requirements in the cytoplasmic portion of several cytokine receptors.

Amino Acid Sequence↗
PubMed1993

Overexpression of mitochondrial manganese superoxide dismutase promotes the survival of tumor cells exposed to interleukin-1, tumor necrosis factor, selected anticancer drugs, and ionizing radiation.

Interleukin-1 (IL-1) and tumor necrosis factor (TNF) selectively induce mitochondrial manganese superoxide dismutase (MnSOD) production in various cell types. We have evaluated the capacity of tumor cells that overexpress MnSOD to recover from the cytostatic and cytotoxic effects of cytokines (IL-1 and TNF), chemotherapeutic agents, and ionizing irradiation. Clones of human melanoma cell line, A375, which overexpressed MnSOD after sense MnSOD cDNA transfection, showed increased recovery from treatment with cytostatic and cytotoxic doses of IL-1 alpha and TNF alpha, whereas clones of A375 cells that were transfected with anti-sense MnSOD cDNA recovered less well than normal cells from IL-1 alpha and TNF alpha. In addition, Chinese hamster ovary (CHO) cells transfected with sense MnSOD cDNA showed increased survival after treatment with doxorubicin, mitomycin C, and gamma (gamma) radiation in vitro. It is hypothesized that mitochondrial MnSOD, by scavenging oxygen radicals induced by cytokines, some cytotoxic drugs, and ionizing radiation, is protective and promotes the survival of cells from the lethal effects of these treatments.

Animals↗
PubMed1993

Restriction landmark genomic scanning method and its various applications.

We have developed a new genome scanning method (restriction landmark genomic scanning (RLGS), based on the new concept of using restriction enzyme sites as landmarks. RLGS employs direct end labeling of the genomic DNA digested with a restriction enzyme and two-dimensional electrophoresis with high-resolution. Its advantages are: (i) high-speed scanning ability, allowing simultaneous scanning of thousands of restriction landmarks; (ii) extension of the scanning field using different kinds of landmarks in an additional series of electrophoresis; (iii) application to any type of organism because of direct-labeling of restriction enzyme sites and no hybridization procedure; and (iv) reflection of the copy number of the restriction landmark by the spot intensity which enables distinction of haploid and diploid genomic DNAs. The RLGS method has various applications because it can be used to scan for physical genomic DNA states, such as amplification, deletion and methylation. The copy number of the locus of a restriction landmark can be estimated by the spot intensity to find either an amplified or deleted region. The methylation state of genomic DNA can also be discovered by use of a methylation-sensitive restriction enzyme sites as a restriction landmark (restriction landmark genomic scanning for screening methylated sites, RLGS-M). This article introduces the basic principle of RLGS and its applications to the analysis of cancer, mouse mutant DNAs and tissue-specific methylation, showing the usefulness of RLGS for a variety of biological fields.

Animals↗
PubMed1993

Structural change of crossbridges of rabbit skeletal muscle during isometric contraction.

Structural changes of crossbridges during isometric contraction have been studied by electron microscopy. Chemically skinned rabbit fibres were rapidly frozen either in activating solution or in ATP-free (rigor) solution, freeze-substituted and embedded. Longitudinal sections of muscle fibres show that the number of crossbridges in active fibres (isometric contraction) is approximately the same as in rigor fibres. Crossbridges of the active and rigor states differ in their shapes, angles and manner of arrangement on the thin filaments. In rigor many crossbridges are wide near the thin filaments and narrow near the thick filament shafts; in active fibres they have more uniform width along their length. The angle of the crossbridges in active fibres is somewhat variable. The average angle is approximately 90 degrees to the filament axis. The crossbridges are arranged on the thin filament retaining the 14.3 nm thick filament periodicity. The crossbridges in rigor are tilted and their arrangement near the thin filament reveals the 36 nm actin periodicity. The variability in the shapes of the crossbridges in active fibres is still higher when we look at them in cross-sections of muscle fibres. The crossbridge shapes in the cross-sections were classified and the relative frequency of different shapes was determined. The shapes that are commonly observed in active fibres are similar in that the majority of the mass of the crossbridges is farther away from the thin filament than the crossbridges in rigor fibres.

Actins↗
PubMed1993

Blockade of glutamate excitotoxicity and its clinical applications.

Glutamate has long been known to play a vital role in the normal functioning of neurons, serving as the main excitatory neurotransmitter in the central nervous system. The normal function of glutamate, as a means of communication from one neuron to the next, breaks down in certain disease states. Under particular scrutiny has been the etiology of neuronal damage caused by ischemic disease, seen most commonly in cerebrovascular embolic disease, commonly known as a stroke. It has been shown that damage associated with ischemic disease in the brain is not a direct result of hypoxia or deprivation of metabolic intermediates. In fact, the crucial role is played by an excessive efflux of glutamate by ischemic neurons, which then in turn activates pathways in post-synaptic neurons leading to acute cell swelling and later, cell death. An extremely hopeful development in the field of glutamate excitotoxicity has been the application of therapeutic methods aimed at attenuating the damaging action of glutamate, in an effort to decrease morbidity associated with such common diseases as stroke and other neurodegenerative disorders.

Animals↗
PubMed1993

Flash and smash: rapid freezing of muscle fibers activated by photolysis of caged ATP.

A new approach was used to study transient structural states of cross-bridges during activation of muscle fibers. Rabbit skinned muscle fibers were rapidly and synchronously activated from the rigor state by photolysis of caged ATP in the presence of Ca2+. At several different times during the switch from rigor to fully active tension development, the fibers were rapidly frozen on a liquid helium-cooled metal block, freeze-substituted, and examined in an electron microscope. The limits of structural preservation and resolution with this technique were analyzed. We demonstrate that the resolution of our images is sufficient to draw the following conclusions about cross-bridge structure. Rigor cross-bridges point away from the Z-line and most of them are wider near the thin filaments than near the backbone of the thick filaments. In contrast, cross-bridges in actively contracting fibers stretch between the thick and thin filaments at a variable angle, and are uniformly thin. Diffraction patterns computed from contracting muscle show layer lines both at 38 and 43 nm indicating that active cross-bridges contribute mass to both the actin- and myosin-based helical periodicities. The images obtained from fibers frozen 20 ms after release of ATP show a mixture of rigor and active type cross-bridge configurations. There is little evidence of cross-bridges with the rigor shape by 50 ms, and the difference in configurations between 50 and 300 ms after photolysis is surprisingly subtle.

Adenosine Triphosphate↗
PubMed1993

A new method for measuring small local vibrations in the heart using ultrasound.

In order to diagnose ventricular dysfunction based on the acoustic characteristics of the heart muscle of the ventricle, it is necessary to detect vibration signals from various parts of the ventricular wall. This is, however, difficult using previously proposed ultrasonic diagnostic methods or systems. The reason is that the amplitude of the cardiac motion is large during one beat period which produces large fluctuations in the transit time required for ultrasonic waves to travel from the transducer to the heart and back. This paper proposes a new method for overcoming this problem and accurately measuring small vibrations of the ventricle wall using ultrasound. In this method, the demodulated ultrasound signal reflected at the heart wall is converted from analogue to digital (A/D) signal at a high sampling frequency; from the resultant digital signal, the velocity of the wall is accurately obtained over a wide dynamic range based on the Doppler effect. The proposed method is preliminarily applied to the detection of small vibrations on the aortic wall and the interventricular septum. The new method offers potential for research in acoustical diagnosis of heart and artery dysfunction.

Adult↗
PubMed1993

Protective effects of raw vegetables and fruit against lung cancer among smokers and ex-smokers: a case-control study in the Tokai area of Japan.

In a hospital-based case control study, the protecting effects of fruit, raw and green vegetables against lung cancer risk among male smokers were studied in 282 cases and the same number of controls. The current smokers showed a 6.61-fold increased risk of lung cancer. The odds ratio (OR) declined markedly with starting age of smoking habit and increased markedly with number of cigarettes smoked per day. The ex-smokers showed a 3.56-fold increased risk of lung cancer. The ORs gradually decreased with years passed since cessation of smoking. In the single factor analysis, significant protective effects of fruit, raw vegetables, green vegetables, lettuce and cabbage against lung cancer were found. The risk for all lung cancer decreased to 0.45 (95% confidence intervals (CI) 0.30-0.67), 0.64 (95% CI 0.43-0.97) and 0.44 (95% CI 0.26-0.73) with increment of intake frequency of fruit, raw and green vegetables respectively. The OR for lung cancer decreased to 0.41 (95% CI 0.24-0.72) and 0.56 (95% CI 0.32-0.99) with increasing intake frequency of fruit and raw vegetables among current smoking males. Lettuce and cabbage showed protective effects against lung cancer, and the OR for risk of lung cancer decreased to one-half among the high intake frequency group. The risk of lung cancer among current smokers declined markedly with increasing intake of lettuce and cabbage. A similar effect was observed among ex-smokers and non-smokers, but there was no statistical significance. In the multivariate analysis, fruit and raw vegetables showed the strongest protective effects against lung cancer among current smokers (P = 0.01). Among ex-smokers, the protective effect of fruit is also statistically significant (P = 0.03). These results suggest that fruit and raw vegetables may play an important role in protecting smokers from lung cancer.

Adult↗
PubMed1993

Close association between Streptococcus sobrinus in the saliva of young children and smooth-surface caries increment.

Three hundred and thirty-eight children (age range 3-5 years) were examined for the presence of mutans streptococci in their saliva. They were divided into four groups according to the prevalent species that were isolated: (1) Streptococcus mutans and Streptococcus sobrinus group (S. mutans > or = 10(3) CFU/ml and S. sobrinus > or = 10(3) CFU/ml); (2) S. mutans group (S. mutans > or = 10(3) CFU/ml but S. sobrinus < 10(3) CFU/ml); (3) S. sobrinus group (S. sobrinus > or = 10(3) CFU/ml but S. mutans < 10(3) CFU/ml), and (4) children with mutants streptococci absent or barely detectable (mutants streptococci < 10(3) CFU/ml). The previous caries experience was compared among the groups, as was the caries increment during a 6-month period after the bacterial examination. The subjects in the S. sobrinus group had both higher caries and higher decayed teeth and surface increments than the S. mutans group. The mean decayed smooth-surface increment (delta d-surface) for the S. sobrinus group was 2.6 and was significantly higher than 0.8 for the S. mutans group. For the subjects with delta d-surface > or = 4, the mean number of S. sobrinus in the saliva was 4.29 x 10(5) CFU/ml and was significantly higher than 0.32 x 10(5) CFU/ml for the subjects without delta d-surface. There was no significant difference in the mean number of S. mutants in saliva between the subjects with and without delta d-surface. The prevalence of S. sobrinus in saliva was more closely associated with future caries activity, especially with smooth-surface caries increment, than the prevalence of S. mutants.

Analysis of Variance↗
PubMed1993

Effect of labor and prostaglandins on phenylethanolamine N-methyltransferase in human fetal membranes.

Biochemical investigations have shown the presence of the enzyme phenylethanolamine N-methyltransferase (PNMT), which converts norepinephrine (NE) to epinephrine (E) in human pregnant tissues, e.g. myometrium and fetal membranes. The enzymatic activity of PNMT in myometrium is known to decrease during labor. In the present study, PNMT activity in chorio-decidua was measured and the effect of labor and prostaglandins (PG) on PNMT activity was determined. A cytosol fraction of chorio-decidua was incubated with [14C]-S-adenosyl-L-methionine and normetanephrine for 60 min to measure PNMT activity. Fetal membranes were obtained at elective Cesarean section and normal vaginal delivery from full term pregnant women, and the activity of PNMT in chorio-decidua was compared. Significantly lower activity in chorio-decidua obtained from normal vaginal delivery than that from elective Cesarean section was observed. The concentration of 13, 14-dihydro-15-keto-prostaglandin F2 alpha (DHK-PGF2 alpha) in amniotic fluid obtained at normal vaginal delivery were measured by RIA, and the relationship of the DHK-PGF2 alpha level to PNMT activity was studied. There was a significantly negative correlation between the concentration of DHK-PGF2 alpha in amniotic fluid and PNMT activity in chorio-decidua. When various concentrations of PGF2 alpha were pre-incubated with mined chorio-decidua for 2 h, PNMT activity was decreased in a dose dependent manner. These results indicated that PGF2 alpha might affect the bioconversion of NE to E in fetal membranes. The presence of this enzyme in fetal membranes may play an important role in regulating the concentration of catecholamines during pregnancy and parturition.

Dinoprost↗
PubMed1993

Rigid spine syndrome and nocturnal alveolar hypoventilation.

A 17-year-old Japanese woman with rigid spine syndrome (RSS) presented with respiratory failure leading to CO2 narcosis. The clinical symptoms were drowsiness, asterixis and cardiac arrhythmias. Tracheostomy and temporary ventilatory support abolished these symptoms. However, polygraphic sleep studies without a ventilator revealed Cheyne-Stokes respiration and profound arterial oxygen desaturation during rapid eye movement sleep. Nocturnal ventilatory support improved not only nocturnal hypoxemia, but daytime blood gas values during spontaneous breathing. These findings indicate that the onset of respiratory failure is preceded by severe nocturnal hypoxemia and that the evaluation and control of nocturnal respiratory insufficiency is essential for RSS patients.

Adolescent↗
PubMed1993

[Dyskinesias in infections of the central nervous system].

Dyskinesia, here, is considered to be synonymous with abnormal involuntary movement (AIM). AIMs are recognized in various infections of the central nervous system, of which Creutzfeldt-Jakob disease (CJD) and subacute sclerosing panencephalitis (SSPE) are thought to be the most important. The two show myoclonus and other similar features in common except age of onset. The myoclonus is classified under the non-stimulus-sensitive and periodic one characterized by a long duration and a relationship to periodic synchronous discharge (PSD) in EEG. The rhythm is, however, somewhat different and quicker in CJD (0.5-2 Hz) than in SSPE (0.05-0.2 Hz). In the acquired immunodeficiency syndrome (AIDS), AIMs, including tremor, myoclonus and some others are also noted.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Two autopsy cases of sporadic amyotrophic lateral sclerosis with 20-year-clinical course without respirators].

The present paper concerns the clinicopathological study of two patients with sporadic amyotrophic lateral sclerosis (ALS) with 21 or 22 years' clinical course without respirators. The two cases developed marked upper motor neuron signs and continually progressive paralysis. Involvement of the facial and bulbar muscles remained fairly mild. At autopsy, the anterior horns showed marked loss of motor neurons associated with numerous reactive astrocytes. On the other hand, the motor cortex and the pyramidal tract showed diminution of Betz cells and large myelinated fibers but no positive materials by fat stain. In addition, the anterolateral funiculi of the spinal cords revealed widespread myelin pallor. One of the case showed intracytoplasmic eosinophilic inclusions in some neurons of the medullary reticular formation. Recent articles have reported several rapidly progressive ALS patients who developed ophthalmoplegia, while on respirators, and widespread degeneration in the CNS. By contrast, our extremely slowly progressive ALS patients developed alterations confined to upper and lower motor neurons. There may exist some diversities in ALS.

Aged↗
PubMed1993

[Rhythmical involuntary movement at rest associated with olivo-ponto-cerebellar atrophy (OPCA)].

The authors analyzed rhythmical involuntary movements at rest, which appeared as complications in 12 (sporadic 11, hereditary 1) out of a total of 139 cases (sporadic 99, hereditary 40) of olivo-ponto-cerebellar atrophy. These movements tended to be seen in patients with sporadic OPCA of longer illness duration and at more advanced stages. They were distributed over the face, neck and extremities. Palatal myoclonus was observed in only one case. The movements were exacerbated by maintenance of a fixed posture, motion and mental stress, and stopped during sleep. In some cases, clonazepam, trihexyphenidyl or 1-Dopa was effective. In the surface electromyogram, rhythmical grouped discharges of 2-4 Hz were recorded only on agonist muscles or on both agonist and antagonist muscles synchronously, which is characteristic of skeletal myoclonus. However, pathological study of 3 cases with involuntary movements revealed marked putaminal degenerations as compared with 3 uncomplicated cases. This suggests that these rhythmical movements might be related to parkinsonian tremor.

Adolescent↗
PubMed1993

[Reoperation in patients with thymoma].

For past seven years, reoperations were carried out for six patients with thymoma and myasthenia gravis (MG). Of six patients, five patients were suspected recurrent thymoma and remaining one patient was diagnosed as the residual thymus after thymothymectomy or thymomectomy. Myasthenia gravis has been progressing in five patients after initial operation except for one patient. Two cases of pleural dissemination tumors, one case of local recurrent thymoma and one case of the residual thymus were confirmed by surgery, remaining two patients had no recurrent tumor. As surgical procedure, median sternotomy using for reoperation has a great surgical risk, because left brachiocephalic vein closely adhered to the sternum is apt to be injured. Clinical symptoms of MG were improved in all the patients after reoperation regardless of recurrent tumor.

Adult↗