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Biomedical subjects

K Deguchi

Publications and source records attributed to K Deguchi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Association of osteopontin with ischemic axonal death in periventricular leukomalacia.

Osteopontin (OPN) is a bone matrix protein expressed my macrophages and related to the process of tissue calcification, and is also known to protect ischemic cells. To understand how OPN is involved in the process of ischemic axonal death in periventricular leukomalacia (PVL), we examined the immunoreactivity of OPN and ionized calcium binding adaptor molecule 1 (Iba1; microglia/macrophage marker) at various stages of PVL. OPN immunoreactivity paralleled the number of Iba1-positive foam cells; a finding which suggests the production of OPN protein by foam cells. OPN immunoreactivity was not found in either normal white matter or acute PVL lesions, but was detected at the subacute and chronic stages in swollen and calcified axons bordering the ischemic zone. These findings suggest that OPN is closely associated with death of swollen axons at the periphery of the ischemic zone, regulating the presence or absence of calcification.

Axons↗
PubMed2000

Substance P immunoreactivity in Rett syndrome.

Severe autonomic dysfunction occurs in Rett syndrome (RS). Substance P, a tachykinin peptide that localizes to several brain regions, including the autonomic nervous system, is reduced in the cerebrospinal fluid of patients with RS. The anatomic localization and intensity of substance P immunoreactivity and glial fibrillary acidic protein-positive astrocytes in the brains of 14 patients with RS were compared with those in the brains of 10 age-matched normal patients. Substance P immunoreactivity expression was significantly decreased in RS tissue compared with control tissue in the following regions: dorsal horns, intermediolateral column of the spinal cord, spinal trigeminal tract, solitary tract and nucleus, parvocellular and pontine reticular nuclei, and locus ceruleus. A less significant decrease of substance P immunoreactivity occurred in the substantia nigra, central gray of the midbrain, frontal cortex, caudate, putamen, globus pallidus, and thalamus. Antiglial fibrillary acidic protein-positive astrocytes were increased in the areas in which substance P immunoreactivity was decreased and in other brain regions. Because many of the brain regions with the greatest decrease in substance P immunoreactivity are involved in the control of the autonomic nervous system, especially the solitary tracts and reticular formation, reduced substance P may contribute to the autonomic dysfunction in RS.

Adolescent↗
PubMed2000

Topographical features of the sensory-evoked responses in malformed brains.

To reveal the functional organization of the somatosensory area in the dysgenetic cortex, somatosensory-evoked potentials were examined in seven patients with congenital brain anomalies diagnosed by magnetic resonance imaging, including six patients in whom multichannel recordings over the scalp were used. In four patients with polymicrogyria/pachygyria and two with lissencephaly, the early cortical responses, frontal P20 and parietal N20, were absent in the cortex contralateral to the stimulated side. The first cortical response was a positive wave that appeared predominantly over the centroparietal area in five patients, and in the frontal area in the other patient with polymicrogyria/pachygyria. These findings suggest that the differentiated somatosensory function is distributed normally in the centroparietal cortex in most cases of widespread cortical dysplasia. However, the absence of P20/N20 may indicate a hypoplastic central sulcus or functionally undifferentiated subdivision of the somatosensory cortex in these patients. The absence of cortical responses in the patient with holoprosencephaly may correspond with growth failure of the thalamocortical afferent projections in this disorder.

Adolescent↗
PubMed2000

Diagnosis of disseminated intravascular coagulation by hemostatic molecular markers.

In the present study, the positive rate of thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), soluble fibrin monomer (sFM), and D-dimer for the diagnosis of disseminated intravascular coagulation (DIC) was evaluated. The study comprised 307 patients with DIC, 123 with pre-DIC, and 121 with non-DIC. Plasma levels of TAT, PPIC, sFM, and D-dimer were significantly higher in DIC and pre-DIC patients than in non-DIC patients. In DIC patients, the positive rate of sFM was high and that of D-dimer was low; the positive rate of PPIC was higher in patients with hematopoietic malignancy than in those without this disease. In pre-DIC patients, the positive rate of all markers was low (<0.16), and the positive rate of PPIC was relatively high. In non-DIC patients, the positive rate of all hemostatic markers was low (<0.16), that of sFM being the lowest. Scoring the positive rate of TAT, PPIC, and sFM disclosed the following results: 72% of DIC patients had three or more points, 17.6% of pre-DIC patients had three or more points, and almost all (96.6%) non-DIC patients had two or less points. Scoring the positive rate of TAT, PPIC, and D-dimer disclosed the following results: 52.9% of DIC patients and 27.4% of pre-DIC patients had three or more points and almost all (96.7%) non-DIC patients had 2 or less points. These data suggest that the combination of TAT, PPIC, and sFM is useful for making the diagnosis of DIC.

Antifibrinolytic Agents↗
PubMed2000

Study of cardiovascular risk factors and hemostatic molecular markers in elderly persons.

In this study, plasma concentrations of hemostatic molecular markers were investigated in 118 elderly persons with normal renal function (aged 65 to 97 years) who could manage their activities of daily living (ADL) by themselves, to find a strategy for conservation or elevation of ADL and quality of life (QOL). In all subjects, the frequency by which hemostatic markers exceeded their upper limit of normal range was 35.9% for thrombin-antithrombin HI complex (> or = 3.7 ng/ml), 38.3% for soluble fibrin monomer (> or = 4.0 microg/ml), 41.8% for D-dimer (> or = 1.0 microg/ml), 49.0% for plasmin-alpha2 plasmin inhibitor complex (> or = 1.0 microg/ml), and 53.7% for thrombomodulin (> or = 20 ng/ml). The mean plasma levels of these markers were slightly higher than the upper limit of their normal range. These markers were also investigated in samples of patients with and without cardiovascular risk factors and with and without cardiovascular diseases (ischemic heart disease and/or cerebral infarction). Furthermore, the results were analyzed in relationships between cardiovascular disease and cardiovascular risk factor or aging. The findings suggest that aging exerts a stronger influence on plasma levels of these hemostatic molecular markers than the presence of cardiovascular risk factors and cardiovascular diseases. From the viewpoint for conservation or elevation of ADL and QOL in elderly persons, also other factor, such as drug intake, lifestyle, aging, and so on, must be considered to clarify the relationship between the plasma levels of the hemostatic molecular markers and cardiovascular risk factors or cardiovascular diseases.

Aged↗
PubMed2000

Hemostatic abnormalities in patients with thrombotic complications on maintenance hemodialysis.

Before hemodialysis (HD), plasma levels of tissue factor (TF), free-TF pathway inhibitor (TFPI) and thrombomodulin (TM) were significantly higher in patients with HD than in healthy volunteers. Plasma levels of (T-F) TFPI and plasmin plasmin inhibitor complex (PPIC) were significantly higher in patients with HD than in healthy volunteers. During HD, plasma levels of TF and (T-F) TFPI were not significantly increased, but plasma levels of total TFPI and free TFPI at 1 hour after and at the end of HD were significantly increased, compared with levels before start of HD. Plasma level of PPIC 1 hour after start of HD was significantly higher than before start of HD, and plasma levels of thrombin antithrombin complex (TAT), PPIC, D-dimer, TM, and protein C (PC) at the end of HD were significantly higher than before start of HD. In patients with thrombosis complications, plasma TF levels were significantly higher than in patients without thrombotic complications during HD. Plasma levels of PC were significantly lower in patients with thrombotic complications than in patients without thrombotic complications. There was no significant difference between both groups during HD in hemostatic parameters, with the exception of TF and PC. Hemostatic abnormalities existed in patients with HD; especially, increased TF and decreased PC might cause thrombotic complications.

Antifibrinolytic Agents↗
PubMed2000

Ascorbic acid stimulation of production of a highly branched ,beta-1,3-glucan by Aureobasidium pullulans K-1--oxalic acid, a metabolite of ascorbic acid as the stimulating substance.

The production of a highly branched beta-1,3-glucan by Aureobasidium pullulans K-1 in Czapek's medium has been found to be stimulated by ascorbic acid. When the culture supernatant, after removal of polysaccharide from the culture filtrate by ethanol precipitation, was concentrated, then added to a new medium and this strain was cultured in the medium, the polysaccharide production was stimulated the same as when L-ascorbic acid was added to the medium. The stimulating substance was partially purified from the supernatant, and was found to be oxalic acid; 0.03% oxalic acid was the most effective concentration for the stimulation of polysaccharide production. The stimulating substance, oxalic acid, was proved to be derived from ascorbic acid added to a medium in an experiment using L-[1-14C]ascorbic acid. We suggest that oxalic acid generated from the metabolism of ascorbic acid in cells of Aureobasidium pullulans K-1 participated in the stimulation of the polysaccharide production by ascorbic acid.

Ascorbic Acid↗
PubMed2000

[A case of amyotrophic lateral sclerosis presenting with circulatory collapse during artificial respiration].

A 71-year-old man developed dysarthria and difficulty of swallowing in December 1997. He was diagnosed as having the bulbar type of amyotrophic lateral sclerosis (ALS). In November 1998, he was admitted to our hospital to undergo treatment for bulbar palsy and respiratory discomfort. In January 1999, ventilatory support (synchronous intermittent mandatory ventilation) during sleep at night was initiated. Severe progressive hypotension and loss of consciousness were observed soon after the start of artificial respiration, and both symptoms disappeared after artificial respiration was discontinued. This phenomenon was observed consistently during ventilatory support, while unpleasant stimuli such as bronchoscopy and replacement of the cannula tube induced severe hypertension. To clarify the mechanism of underlying these abnormal changes in blood pressure, autonomic function tests were performed while awake during the daytime. Ventilatory support induced a drop in blood pressure accompanied by a decrease in influx speed to the right ventriculum, the latter of which suggested a reduction in venous return. These values returned to the baseline following detachment of the ventilator. A 60 degrees head-up tilt (HUT) angle and standing from a supine position produced orthostatic hypotension, the latter of which was accompanied by a compensatory increase in pulse rate. The basal supine plasma noradrenaline (NA) level was high and the HUT showed a slight elevation of NA. The basal supine plasma arginine vasopressin (AVP) level was within the normal range, whereas the AVP level did not increase during HUT. Urinary secretion rates of NA and 3-methoxy-4-hydroxy-phenylglycol were elevated. A cold pressor test demonstrated reflex hypertension. The oculovagal reflex, coefficient of variation of R-R intervals. (CVR-R) and increase in pulse rate in response to atropine administration were within the normal range. The combination of midodrine, L-dihydroxyphenylserine (DOPS) and increasing intravascular volume via continuous intravenous drip infusion relieved the circulatory collapse during artificial respiration. In conclusion, the present case of ALS had sympathetic hyperactivity, somatosympathetic reflex and dysregulation of the baroreflex arc. Degeneration of central autonomic network, including the hypothalamus and the central nucleus of the amygdala, which has been shown in some ALS patients, might underlie the autonomic abnormalities in this patient.

Aged↗
PubMed2000

[A case of neuro-Behçet's disease with HLA B54 and predominant cerebral white matter lesions].

We report a 55-year-old woman with neuro-Behçet's disease with HLA B54 and predominant cerebral white matter lesions. She showed a cryptogenic high fever and cerebral cortical symptoms such as perseveration, limbkinetic apraxia and dementia. CSF study showed an increase of cell count and protein and a decrease of sugar. MRI showed diffuse T2-high signal intensity mainly in the subcortical white matter of left parieto-occipital lobes and basal ganglia. Her clinical signs greatly improved after administration of prednisolone. Her HLA type was not B51 but B54. Though our patient did not completely satisfy clinical criteria for neither neuro-Behçet's disease nor Sweet's syndrome, she showed partial features of both Behçet's disease and Sweet's syndrome.

Behcet Syndrome↗
PubMed2000

A new current dipole tracing method from EEG which is very useful in research of human brain activity in the space station.

The space station is available from 2004 for scientific research including human physiology and medicine. In that instance, non-invasive research of human brain in the microgravity condition was highly required. The present newly developed dipole tracing method fits this research purpose, by determining current source in the brain from EEG activity. EEG is also very helpful to monitor the conditions of subjects in various hazard cases. We strongly recommend to use this apparatus in the space station.

Brain Mapping↗
PubMed1999

Antiseptic susceptibility and distribution of antiseptic-resistance genes in methicillin-resistant Staphylococcus aureus.

We examined the antiseptic susceptibilities and distribution of antiseptic-resistance genes qacA and smr in 98 isolates of methicillin-resistant Staphylococcus aureus obtained in 1992. Seventy-one strains were resistant to antiseptics. The qacA and smr genes were detected in 10 and 20 strains, respectively. The remaining 41 strains without qacA and smr were divided into two groups that exhibited low-level (n = 22) and high-level (n = 19) resistance to acriflavin. DNA cloning and sequencing suggested that norfloxacin-resistance gene norA was responsible for the high-level resistance to acriflavin. Our results indicated that four or more antiseptic-resistance genes exist in methicillin-resistant S. aureus and that antiseptic-resistant methicillin-resistant S. aureus strains without qacA and smr are widely spread in Japan.

Acriflavine↗
PubMed1999

Excessive extramedullary hematopoiesis in Cbfa1-deficient mice with a congenital lack of bone marrow.

Cbfa1, a transcriptional factor that belongs to the runt-domain gene family, plays a pivotal role in osteogenesis. Cbfa1-deficient mice completely lacked both intramembranous and endochondral bone formation owing to the maturational arrest of osteoblasts, resulting in a total lack of bone marrow throughout the entire skeleton. To investigate the development of hematopoiesis in Cbfa1-deficient mice, hematopoietic tissues and peripheral blood were examined. Colony-forming assays of yolk sac at embryonic day 10.5 (E10.5) and liver at E12.5 showed normal numbers of hematopoietic precursors in the mutant embryos. Further, histological examination and flow-cytometric analysis showed normal hematopoietic development of liver and spleen in the mutant embryos until E17.5. However, mutant embryos at E18.5 showed large hematopoietic foci in the periportal area of liver and mild splenomegaly with dilated vessels, and an increase of myeloid cells was observed in both organs. Flow-cytometric analysis also demonstrated a relative increase of granulocytes and a relative decrease of B-cells reciprocally in the livers and spleens of the mutant embryos. Colony-forming assays showed that the frequency of colony-forming unit-culture (CFU-C) was elevated in liver, and both the frequency and total number of CFU-C were increased in spleen of mutant embryos at E18.5. Moreover, leukoerythroblastosis was observed in peripheral blood of the mutant embryos. These data demonstrate that the congenital lack of bone marrow caused excessive levels of extramedullary hematopoiesis in both liver and spleen at the late embryonic stage.

Animals↗
PubMed1999

Increased truncated form of plasma tissue factor pathway inhibitor levels in patients with disseminated intravascular coagulation.

To evaluate that the relationship between the truncated form of tissue factor pathway inhibitor (TFPI) and the stage of disseminated intravascular coagulation (DIC), we measured the plasma levels of tissue factor (TF) antigen and the intact and truncated forms of TFPI antigens in 41 patients with DIC, 12 with pre-DIC, and 20 with non-DIC. The plasma TF and total TFPI antigen levels were significantly higher in patients with DIC than in non-DIC patients. Plasma levels of intact TFPI antigen in the pre-DIC groups were significantly lower than in the non-DIC and DIC groups. The truncated form of TFPI antigen levels in DIC patients were significantly increased compared with those in non-DIC and pre-DIC patients. The fact that the intact form of TFPI was decreased in pre-DIC patients compared with that in non-DIC patients, suggests that it is consumed in the pre-DIC state and that hypercoagulability occurs in pre-DIC patients. The increased level of the truncated form of TFPI in DIC patients may be attributed to proteolysis of the intact form of TFPI in these patients. The increased level of the truncated form of TFPI may be a useful index for the diagnosis of DIC.

Disseminated Intravascular Coagulation↗
PubMed1999

Hemostatic molecular markers before the onset of disseminated intravascular coagulation.

We retrospectively measured various hemostatic markers in 240 patients with disseminated intravascular coagulation (DIC) before the onset of DIC and in 110 non-DIC patients, and examined their usefulness for the diagnosis of pre-DIC. Changes in prothrombin time ratio and fibrinogen levels were not significant before the onset of DIC. The plasma levels of fibrinogen and fibrin degradation products before the onset of DIC were increased and the platelet count was gradually reduced in nonleukemic patients; these changes were already significant in the non-DIC state. The plasma levels of thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (sFM) were increased before the onset of DIC. In leukemic patients, the plasma levels of sFM on day 5, those of TAT on day 3, and D-dimer on day 1, were significantly increased before the onset of DIC. The levels of most hemostatic markers 7 days before the onset of DIC were not different from those observed in the non-DIC state. In nonleukemic patients, only D-dimer, sFM, and TAT levels were significantly increased 7 days before the onset of DIC compared with values in the non-DIC state. The positive rate of hemostatic markers for the diagnosis of DIC, TAT, and PPIC were high during the pre-DIC and non-DIC groups. The plasma levels of sFM and D-dimer were low in non-DIC and increased gradually during the pre-DIC state. These findings suggest that hemostatic molecular markers such as sFM, D-dimer, and TAT are useful for the diagnosis of pre-DIC, although their cutoff values were different among various diseases.

Antifibrinolytic Agents↗
PubMed1999

Plasma sFas and sFas ligand levels in patients with thrombotic thrombocytopenic purpura and in those with disseminated intravascular coagulation.

Fas, a member of the tumor necrosis receptor superfamily, is 36 kD surface protein containing a single transmembrane region and induces apoptosis by Fas-Fas ligand binding. Soluble Fas (sFas) is produced as the form lacking 21 amino acid residues containing the transmembrane domain by alternative splicing. We found that the plasma sFas levels of 33 patients with thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), 19 patients with disseminated intravascular coagulation (DIC), and 10 non-DIC patients with multiple organ failure (MOF) were significantly higher than those of 21 non-DIC patients without organ failure and those of 25 healthy volunteers. The plasma sFas ligand levels of the TTP/HUS patients, the DIC patients, and the non-DIC patients with MOF were significantly higher than those of the non-DIC patients without organ failure and those of the healthy volunteers. The plasma sFas levels were significantly correlated with the plasma sFas ligand levels in all subjects. The plasma thrombomodulin (TM) levels were increased significantly in the TTP/HUS patients, the DIC patients, and the non-DIC patients with MOF compared with the levels of the non-DIC patients without organ failure and the healthy volunteers. The plasma sFas antigen levels were correlated significantly with the plasma TM levels in all subjects. These findings suggest that the increases of sFas and sFas ligand that cause apoptosis might be related to the vascular endothelial cell injuries in TTP and DIC with organ failure.

Adult↗
PubMed1999

Maturational disturbance of chondrocytes in Cbfa1-deficient mice.

Cbfa1, a transcription factor that belongs to the runt-domain gene family, plays an essential role in osteogenesis. Cbfa1-deficient mice completely lacked both intramembranous and endochondral ossification, owing to the maturational arrest of osteoblasts, indicating that Cbfa1 has a fundamental role in osteoblast differentiation. However, Cbfa1 was also expressed in chondrocytes, and its expression was increased according to the maturation of chondrocytes. Terminal hypertrophic chondrocytes expressed Cbfa1 extensively. The significant expression of Cbfa1 in hypertrophic chondrocytes was first detected at embryonic day 13.5 (E13.5), and its expression in hypertrophic chondrocytes was most prominent at E14.5-16.5. In Cbfa1-deficient mice, whose entire skeleton was composed of cartilage, the chondrocyte differentiation was disturbed. Calcification of cartilage occurred in the restricted parts of skeletons, including tibia, fibula, radius, and ulna. Type X collagen, BMP6, and Indian hedgehog were expressed in their hypertrophic chondrocytes. However, osteopontin, bone sialoprotein, and collagenase 3 were not expressed at all, indicating that they are directly regulated by Cbfa1 in the terminal hypertrophic chondrocytes. Chondrocyte differentiation was severely disturbed in the rest of the skeleton. The expression of PTH/PTHrP receptor, Indian hedgehog, type X collagen, and BMP6 was not detected in humerus and femur, indicating that chondrocyte differentiation was blocked before prehypertrophic chondrocytes. These findings demonstrate that Cbfa1 is an important factor for chondrocyte differentiation.

Animals↗
PubMed1999

Reduction in terminal excitability of nigrostriatal dopaminergic neurons in rats following chronic L-dopa administration.

The effects of chronic L-dopa administration on antidromic excitability and the firing rate of nigrostriatal dopaminergic neurons were investigated in urethane-anesthetized rats. Rats that received daily L-dopa (100 mg/kg) and carbidopa (25 mg/kg) for 60 days showed a marked decrease in terminal excitability compared with the controls. There were no significant differences in the firing rates between the two groups. This finding may be related to impaired striatal dopamine release from exogenous L-dopa subsequent to chronic L-dopa treatment.

Animals↗