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Biomedical subjects

M Kano

Publications and source records attributed to M Kano.

At least 145 records · Page 8Linked to original sources
PubMed1994

Factor VIII can be positive in a special type of malignant lymphoma, intravascular malignant lymphomatosis: an immunohistochemical investigation.

This report presents seven cases of intravascular malignant lymphomatosis (IML). The patients exhibited clinical signs and symptoms of multiple cerebral infarctions and polyradiculopathy, but in each case the diagnosis of IML was only established by postmortem examination. The autopsies revealed that almost every organ was involved and that there were atypical cells which had proliferated intravascularly. This was especially remarkable in the central nervous system. Extravascular extension of the tumor cells was rarely observed. It was documented by immunohistochemical studies that the abnormal cells were B cell lymphoma cells with a high proliferative capacity. Factor VIII, an endothelial cell-related antigen, was detected in the cytoplasm of the tumor cells of two cases (28%), but this finding was considered to represent a non-specific absorption of factor VIII from the thrombi.

Aged↗
PubMed1994

Simultaneous occurrence of adenomas in stomach, duodenal bulb, and colon: disappearance of gastric and duodenal adenomas during oral administration of 5'-deoxy-5-fluorouridine.

The present report concerns a patient who was first diagnosed as having adenoma in the duodenal bulb and subsequently was discovered to have adenomas in the stomach and colon. Surgical procedures including endoscopic resection could not be carried out because the patient had advanced liver cirrhosis. Follow-up colonoscopy no longer detected any polyp in the colon. Ultrasonography demonstrated a slowly growing hypoechoic mass in the liver, which was indicative of hepatocellular carcinoma. Then, single chemotherapy with oral administration of 5'-deoxy-5-fluorouridine was initiated. Surprisingly, repeated esophagogastroduodenoscopy revealed gradual regression of the gastric and duodenal tumors. Findings from the endoscopy and biopsy materials 10 months after the start of therapy showed disappearance of the gastric and duodenal adenomas. Despite enlargement of the hepatic mass, no recurrence of gastric and duodenal tumors has been noted during the past 1 1/2 yr.

Adenoma↗
PubMed1994

[Concomitant graft replacement of the total aortic root and the transverse aortic arch for type A aortic dissection associated with Marfan syndrome: report of a case].

A 25-year-old man of Marfan syndrome with chronic stage aortic dissection of Stanford type A underwent concomitant graft replacement of the total aortic root and transverse aortic arch. The surgical procedure were performed with an aid of extracorporeal circulation, blood cardioplegia, using the techniques of "open distal anastomosis" under the deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion for cerebral protection during circulatory arrest. The operative techniques consisted of total aortic root replacement using a composite graft with Piehler's and Carrel patch technique for left and right coronary artery, and total arch replacement using en bloc distal arch reconstruction and a composite graft replacement for innominate artery. There were no neurological complications. In the case of Marfan syndrome, type A aortic dissection involving aortic arch should be treated by concomitant graft replacement of the total aortic root and the transverse aortic arch in order to reduce the late risk of aortic dissection or annular dilatation.

Adult↗
PubMed1994

Four autopsy cases of CNS lymphoma: consideration of unknown causes of death.

The authors present four autopsy cases of primary CNS lymphoma. In each case death was due to different causes. Case 1 was a typical cerebral herniation. Case 2 was brain stem lymphoma diffusely spread after leukemoid reaction. Patient 3 died because of cerebral and brain stem degeneration without evidence of lymphoma cells. Case 4 was unique and the cause of death was not even established by autopsy (definite unknown death case). Taking together these facts, the authors consider the patho-physiology of CNS lymphoma and indicate that herniation is not frequent after various therapeutic treatments.

Aged↗
PubMed1993

Molecular studies of mitochondrial acetoacetyl-coenzyme A thiolase deficiency in the two original families.

We describe mutations identified in stored skin fibroblast cell lines from two original probands (JB and JM), first reported with 2-methylacetoacetic aciduria, and shown later to have a deficiency of the K(+)-activated enzyme, mitochondrial acetoacetyl-coenzyme A thiolase (T2). JB is homozygous for a 4-base insertion (GCAG) which is derived mutation. The primary mutation is an AG/gt to AG/gc transition at the 5'-splice-junction site in intron 11. An alternative splice site 4 bp downstream (Ggcag/gt) is used which causes a frame shift and replaces 39 C-terminal residues by 70 nonfunctional residues. JM is homozygous for a mutation in the translation-initiation codon (ATG to AAG). By expression analyses the JB mutation (IVS11nt2) causes an unstable T2 polypeptide and the JM mutation (M1K) severely impairs T2 mRNA translation. The JB allele associates with Dutch ancestry (no consanguinity) and the JM allele with Chilean ancestry (distant consanguinity).

Acetyl-CoA C-Acetyltransferase↗
PubMed1993

Mechanism of inhibitory action of capsaicin on particulate axoplasmic transport in sensory neurons in culture.

The inhibitory effect of capsaicin on axoplasmic transport in cultured dorsal root ganglion cells was analyzed by video-enhanced contrast microscopy. Capsaicin inhibited particle transports in a dose-dependent manner, irrespective of the diameter of axons. The effect of capsaicin was reversible at low concentrations. Capsaicin affected both the anterograde and retrograde transport. Large organelles were more sensitive to capsaicin than small ones in the retrograde transport. An experiment using calcium-sensitive dye, Fura 2, indicated that capsaicin raised the intraneuronal free calcium concentration preceding the inhibition of the transport. Electron microscopy revealed that microtubules and neurofilaments are disorganized and disoriented by capsaicin. We reached a conclusion that capsaicin inhibits fast axoplasmic transport of both anterograde and retrograde directions in all types of somatosensory neurons in culture by disorganizing intraaxonal cytoskeletal structures, through the elevated intracellular Ca2+ concentration.

Animals↗
PubMed1993

Gametocytogenesis induction by Berenil in cultured Plasmodium falciparum.

Berenil, which is known to inhibit synthesis of nucleic acid, DNA and RNA, and polyamine, induced gametocytogenesis in cultured Plasmodium falciparum, although the mechanism by which Berenil induces gametocytogenesis is unknown. Asexual parasites of a strain of P. falciparum that seldom produce gametocytes in in vitro culture began gametocytogenesis after 2-24 hr treatment with RPMI 1640 medium containing Berenil (final concentration, 0.1-10.0 micrograms/ml) with horse serum. Gametocytogenesis was consistently observed from 3 days after the addition of Berenil to culture. After parasites were cultivated in RPMI 1640 medium containing Berenil (final concentration, 3.0-10.0 micrograms/ml) and concanavalin A with horse serum for 2 hr, Berenil and concanavalin A were removed from culture medium by centrifugation. Nevertheless, induction of gametocytogenesis was observed. The addition of concanavalin A (final concentration, 10 micrograms/ml) to RPMI 1640 medium containing Berenil enhanced the induction of gametocytogenesis by Berenil. However, when RPMI 1640 medium with concanavalin A was used without the addition of Berenil, no gametocytogenesis was observed as in RPMI 1640 medium alone.

Animals↗
PubMed1993

Assessment of area at risk and efficacy of treatment in patients with acute coronary syndrome using 99mTc tetrofosmin imaging in humans.

The determination of the myocardium at risk before intervention and the change in that region after intervention constitute a promising measurement tool for the assessment of acute therapy. A new 99mTc labeled myocardial blood flow tracer, 99mTc tetrofosmin, is expected to enable the evaluation of myocardium at risk because of the absence of redistribution. This preliminary study was performed in 9 patients with acute coronary syndrome (4 unstable angina and 5 acute myocardial infarction) to investigate whether recovery of perfusion by tetrofosmin imaging parallels mechanical improvement. Tetrofosmin imaging was performed acutely and 3-30 days later. Visual analysis of defect severity was assessed in both studies. Segments with improvement in perfusion were accompanied by significant wall motion recovery compared with normal and unimproved segments (delta WMI: normal segments 0.40 +/- 0.67, improved segments 1.79 +/- 0.68, unimproved segments -0.15 +/- 0.16, p < 0.01 for improved segments compared with other groups), suggesting the efficacy of this tracer for the assessment of the acute therapy. These data suggest that 99mTc tetrofosmin imaging is a useful method for the assessment of the myocardial area at risk and the efficacy of acute therapy in acute myocardial infarction and unstable angina.

Aged↗
PubMed1993

Organelle transport in cultured smooth muscle cells of the rabbit basilar artery.

Organelle transport in cultured smooth muscle cell from the rabbit basilar artery was observed. The organelles transported in the cells were moving in both centrifugal and centripetal directions. The instantaneous velocities of organelles were 0.84 +/- 0.36 micron/s in the centrifugal direction and 0.86 +/- 0.48 micron/s in the centripetal direction. The transported organelles consisted mainly of lysosomes (67.5%) and mitochondria (29.0%).

Animals↗
PubMed1993

[Findings from slit lamp and histological examination of the anterior capsule in patients with severe anterior capsular shrinkage and opacities after implantation of intraocular lenses].

Seven pseudophakic patients with severe anterior capsular shrinkage and opacities after continuous curvilinear capsulorhexis as a severe anterior capsular shrinkage group and seven pseudophakic patients without the complication as control group were studied in a slit lamp examination of zonular fibers and anterior vitreus body with an indentation mirror. A light and electron microscopic study of the shrunken anterior capsular edge was performed in one case of the severe anterior capsular shrinkage group. No morphological findings suggesting weakness of zonular fibers such as cleavage or scarceness were observed, but reduction in elasticity of the zonular fibers was surmised and degeneration and liquefacation of the anterior vitreus body was observed in the severe anterior capsular shrinkage group. Histological study revealed several layers of proliferated spindle cells and also abundant extracellular matrix, consisting of collagen types I, III and IV, under the monolayer of lens epithelium attached to the anterior capsule. Spindle cells were epithelial cells and considered to be derived from lens epithelium, because the spindle cells were connected by junctional apparatus, which is a feature of epithelium. Severe anterior capsular shrinkage and opacities were due to low ability of the lens supporting system of zonular fibers and anterior vitreus and severe scarring and shrinkage at the anterior capsular edge.

Aged↗
PubMed1993

[Perfusion imaging with 99mTc PPN-1011 for the assessment of myocardial area at risk and the efficacy of PTCA/PTCR in myocardial infarction and unstable angina].

The determination of the myocardium at risk before intervention and the change in that region after intervention constitute a promising measurement tool for the assessment of acute therapy. We used 99mTc PPN-1011 in 4 patients with acute myocardial ischemia (2 patients with acute myocardial infarction, 2 unstable angina) and subsequent successful reperfusion. All 4 patients had perfusion defect on the pre-reperfusion image. Perfusion abnormality on post-reperfusion image was all improved significantly compared with pre-reperfusion image, suggesting the efficacy of acute treatment in acute myocardial ischemia. We conclude that 99mTc PPN-1011 scintigraphy is useful method for the assessment of myocardial area at risk and the efficacy of PTCA/PTCR in myocardial infarction and unstable angina.

Aged↗
PubMed1992

Calcium channels in embryonic chick skeletal muscle cells after cultivation with calcium channel blocker.

The effects of chronic treatment with calcium channel blockers were studied on the expression of voltage-dependent calcium channels (VDCCs) in chick skeletal muscle cells developing in culture. Myotubes were treated after 2 days in culture with either 20 microM D600 or 10 microM nifedipine, and measurements were made of the maximum rate of rise (M.R.R.) of the two components of action potential, operated by T- and L-type VDCCs, respectively. Treatment with either blocker reduced the M.R.R. of the action potential component operated by the L-type VDCC throughout the culture period examined. The M.R.R. of the T-type VDCC component, on the other hand, was unaffected by either treatment. The reduction in the M.R.R. of the L-type component in blocker-treated cells is thought to be due to the down-regulation of the expression of L-type VDCC. Thus, it appears that the expression of L-type VDCC in the chick skeletal muscle cells can be regulated by a function of L-type VDCC, which mediate the entry of Ca2+ into the cells. The physiological significance of the L-type VDCC, which expressed prominently early in the development of skeletal muscle cells, for the differentiation of excitability is discussed.

Action Potentials↗
PubMed1992

Augmentation of transient low-threshold Ca2+ current induced by GTP-binding protein signal transduction system in GH3 pituitary cells.

We characterized the effects of thyrotropin-releasing hormone (TRH; 500 nM) and guanosine 5'-0-3-thiotriphosphate (GTP gamma S; 50 microM) on two types of Ca2+ currents in pituitary-hormone-secretory GH3 cells and were surprised to find marked increases in transient, low-threshold Ca2+ currents (T currents) induced by extracellularly applied TRH or intracellularly applied GTP gamma S. The effect of TRH was blocked by intracellularly applied guanosine 5'-0-2-thiodiphosphate (GDP beta S; 100 microM). The increase in the T current was found to be accompanied by a decrease in long-lasting, high-threshold Ca2+ current (L-current), in response to both TRH or GTP gamma S. These indicate that the enhancement of Ca2+ influx by TRH (500 nM) is largely conferred by T currents in GH3 cells. A reduced concentration of TRH (5 nM) still markedly increased the T current, but failed to decrease the L current. These data suggest that the augmentation of the T currents as well as depression of the L currents by TRH (500 nM), through the activation of a GTP-binding protein, may constitute an important regulatory mechanism of sustained pituitary hormone secretion in GH3 cells.

Animals↗
PubMed1992

Chronic treatment with D600 enhances development of sodium channels in cultured chick skeletal muscle cells.

We have studied the long-term effects of D600, a blocker of L-type voltage-dependent Ca channels (VDCC), on the development of voltage-dependent Na channels (VDNC) that are sensitive to tetrodotoxin (TTX), by electrophysiological measurements of the maximum rate of rise of the TTX-sensitive Na spike in cultured chick skeletal muscle cells. Chronic treatment with D600 (2-20 microM) caused a dose-dependent increase in the density of VDNC. The density of VDNC was increased by 150-250% when D600 was added to the cultures at 20 microM from the second day of culture onward. Co-treatment with an inhibitor of the transcription of RNA from DNA, alpha-amanitin, or with cycloheximide, an inhibitor of protein synthesis, prevented the up-regulation by D600. Nifedipine, a different type of blocker of L-type VDCC, was also effective in increasing the density of VDNC, and BAY K 8644, an agonist of L-type VDCC, had the opposite effect. It is suggested that the effect of D600 was mediated via a mechanism specific for L-type VDCC that involves regulation of cytosolic levels of Ca2+ and protein synthesis de novo.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

Synaptic excitation produces a long-lasting rebound potentiation of inhibitory synaptic signals in cerebellar Purkinje cells.

Persistent changes in synaptic efficacy are thought to underlie the formation of learning and memory in the brain. High-frequency activation of an afferent excitatory fibre system can induce long-term potentiation, and conjunctive activation of two distinct excitatory synaptic inputs to the cerebellar Purkinje cells can lead to long-term depression of the synaptic activity of one of the inputs. Here we report a new form of neural plasticity in which activation of an excitatory synaptic input can induce a potentiation of inhibitory synaptic signals to the same cell. In cerebellar Purkinje cells stimulation of the excitatory climbing fibre synapses is followed by a long-lasting (up to 75 min) potentiation of gamma-aminobutyric acid A (GABAA) receptor-mediated inhibitory postsynaptic currents (i.p.s.cs), a phenomenon that we term rebound potentiation. Using whole-cell patch-clamp recordings in combination with fluorometric video imaging of intracellular calcium ion concentration, we find that a climbing fibre-induced transient increase in postsynaptic calcium concentration triggers the induction of rebound potentiation. Because the response of Purkinje cells to bath-applied exogenous GABA is also potentiated after climbing fibre-stimulation with a time course similar to that of the rebound potentiation of i.p.s.cs, we conclude that the potentiation is caused by a calcium-dependent upregulation of postsynaptic GABAA receptor function. We propose that rebound potentiation is a mechanism by which in vivo block of climbing fibre activity induces an increase in excitability in Purkinje cells. Moreover, rebound potentiation of i.p.s.cs is a cellular mechanism which, in addition to the long-term depression of parallel fibre synaptic activity, may have an important role for motor learning in the cerebellum.

Animals↗
PubMed1992

Identification of TaqI polymorphism in the mitochondrial acetoacetyl-CoA thiolase gene and familial analysis of 3-ketothiolase deficiency.

We analyzed the mitochondrial acetoacetyl-CoA thiolase gene (T2) by Southern blotting. Fifteen unrelated healthy individuals and members of five families with 3-ketothiolase deficiency (3KTD) were analyzed. We found a TaqI polymorphism, the heterozygosity of which was calculated to be 0.5 among healthy Japanese individuals. This restriction fragment length polymorphism (RFLP) proved to be useful for detecting 3KTD patients and its obligatory carriers, at the DNA level and in two out of five 3KTD families. This polymorphism was found to be generated by the presence/absence of a TaqI site in intron 9 of the T2 gene. With in vitro amplification of the genomic region around the TaqI site, this RFLP can be detected within 2 days.

Acetyl-CoA C-Acetyltransferase↗
PubMed1992

Potentiation of GABA-mediated currents by cAMP-dependent protein kinase.

Recent reports described a down-regulation of gamma-aminobutyric acid (GABA)-receptor function in several types of central neurones by cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA). Surprisingly, we found that in cerebellar Purkinje cells (PCs) the membrane permeable-compound 8-bromo-cAMP (500 microM) induced a long-lasting potentiation of both, whole-cell current responses to bath-applied GABA and amplitudes of miniature inhibitory synaptic currents (mIPSCs). When dialyzing the PCs with the specific protein kinase inhibitor peptide (PKIP, 400 micrograms ml-1), the same manipulation failed to induce a potentiation. These results strongly suggest that, in contrast to its action in other types of neurones, activation of PKA up-regulates the GABAA receptor function in cerebellar PCs.

8-Bromo Cyclic Adenosine Monophosphate↗