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Biomedical subjects

S Utsumi

Publications and source records attributed to S Utsumi.

At least 19 recordsLinked to original sources
PubMed1992

A temperature-sensitive CHO-K1 cell mutant (tsTM13) defective in chromosome decondensation and spindle deconstruction in M phase.

A temperature-sensitive CHO-K1 cell mutant, tsTM13, exhibited a delayed cell cycle progression from metaphase to telophase at a nonpermissive temperature and was finally arrested from anaphase to telophase. Metaphase chromosomes were overcondensed and chromosome disjunction in anaphase was uncoordinated. In telophase, sister chromatids were segregated and cytokinesis was completed, but chromosome structure remained in a condensed state and the spindle was not deconstructed. The level of phosphorylation of histones H1 and H3 remained high in the later stages of mitosis and the activity of histone H1 kinase was also maintained at a high level. These results strongly suggest that the pleiotropic defects of tsTM13 cells in mitosis are associated with a lack of inactivation of activated histone H1 kinase.

Amino Acid Sequence↗
PubMed1992

Cytotoxicity of activated platelets to autologous red blood cells.

Gel-filtered human platelets exerted lytic activity on autologous red blood cells (RBC) when they were coincubated at 37 degrees C with platelet-activating agents, such as thrombin, collagen, ADP, LPS or PMA in the absence of plasma. Lysis of activated platelets themselves did not occur during the incubation period examined. Morphological observations showed that RBC exposed to thrombin-activated platelets were fragmented and/or transformed into spherocytes. This haemolytic reaction by thrombin-activated platelets did not occur at 4 degrees C, or in the presence of agents which inhibited glycolysis or elevated intracellular levels of cAMP, indicating that energy-dependent and cAMP-regulated platelet metabolism was required for this reaction. When platelets and RBC were incubated in the same vessel, but were prevented from coming into direct cell to cell contact by means of a membrane barrier, their cytotoxicity was reduced but not eliminated completely. No cytotoxic activity against RBC was detected in platelet-free supernatants obtained by centrifugation after activation of platelets with thrombin. On the contrary, activated and washed platelets retained the activity. These observations suggested that the cytotoxic activity was carried by some diffusible and easily inactivated factors, which were continuously produced and liberated from activated platelets. Cyclo-oxygenase inhibitors inhibited the haemolytic activity of thrombin-activated platelets, suggesting a role for some products of platelet-cyclo-oxygenase pathway in platelet-mediated haemolysis. These results provide the first evidence for a direct role of activated platelets in mediation of RBC-damage in the absence of any plasma factors.

Blood Platelets↗
PubMed1991

[A comparative study of multimodality evoked potentials and computed tomography in head injuries].

Multimodality evoked potentials (EPs) or three types of EPs--auditory brainstem response (ABR), somatosensory evoked potential (SEP), and visual evoked potential (VEP)--were recorded in 51 cases of traumatic intracranial hemorrhage within 3 days after injury. In order to assess these EPs, five EP grades were constructed, from normal, Grade I, to highly abnormal, Grade V. Furthermore, an EP pattern classification was devised to integrate the respective EP grades. Namely, PA, consisting of all three EPs within Grades I-III; PB, composed of one type of EP or both ABR and VEP at Grades IV and V; PC, consisting of both SEP and VEP at Grades IV and V; PD, comprising both ABR and SEP at Grades IV and V; and PE, covering all three EPs at Grades IV and V. PA signifies "no severe damage," PB, "localized damage," PC, "severe cerebral damage," PD, "severe brainstem damage," and PE, "severe diffuse damage." The results when compared with computed tomography (CT) findings were as follows: 1) The size of hematoma correlated with the SEP grade in 16 cases of acute epidural hematoma; a hematoma diameter of 17.5 mm was the threshold value at which SEP abnormalities developed. Eleven patients who underwent surgical removal of the hematoma showed "no severe damage," and the outcome was good. 2) In 13 cases of acute subdural hematoma, six cases revealed "severe cerebral damage" or "severe diffuse damage." In such cases, the degree of damage was not related to the hematoma size, and the outcome was very poor. 3) In 13 cases of a solitary contusional hemorrhage, only one case revealed "severe diffuse damage" and subsequently died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The influence of volume expansion with induced hypertension on vessel reactivities, the blood-brain barrier, and cerebral infarction in cats with one-hour occlusion of the middle cerebral artery.

Thirty anesthetized cats were randomly assigned to three groups of 10 cats each: a 10% hydroxyethyl starch-treated group (10% HAES group), a 6% hydroxyethyl starch-treated group (6% HAES group), or a control group. Cerebral pial arterial reactivities were measured by means of intravital microscopic observation through a cranial window. The middle cerebral artery of the cat was clipped for 1 hour using the transorbital approach, 5 hours later Evans blue dye was injected intravenously, and 30 minutes later the animals was killed. Administration of hydroxyethyl starch or saline was started 15 minutes before clipping and lasted for 1 hour. Total volume administered was 10 ml/kg. Systemic arterial pressure was elevated to about 30 to 40% higher than the resting value by administration of dopamine soon after clipping and maintained for 1 hour. In the hydroxyethyl starch-treated groups, the sizes of infarctions and Evans blue dye leakage were significantly smaller than in the control group. Dye leakage in the 10% HAES group was larger than in the 6% HAES group (statistically significant). Regarding pial arterial reactivities, the caliber of arteries was different in each group after reopening of the clip. Arteries in the control group first returned to some 20% of resting state and redilated 40% or more, arteries in the 6% HAES group returned almost to the resting calibers, and arteries in the 10% HAES group constricted by -20% of the resting calibers. Moreover, 8 of 10 cats in the 10% HAES group showed extravasation of red cells. Only one cat in the 6% HAES group showed extravasation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

In vitro IgG rheumatoid factor production by CD5-negative murine B cells in response to immune complexes of lipopolysaccharide.

We studied the in vitro production of rheumatoid factor (RF) by spleen cells of normal adult mice. IgG RF cross-reactive with rabbit IgG was produced in response to immune complexes of TNP-lipopolysaccharide (LPS) with murine IgG anti-TNP antibody in an Fc-specific manner, but not to a mixture of IgG and LPS. Antibody-uncomplexed LPS induced little IgG RF production, but suppressed the subsequent IgG RF response to antibody-complexed LPS, whereas IgM RF was induced by either LPS or antibody-complexed LPS. The IgG RF production followed as rapid a time course as IgM RF production; the rate of IgG RF production reached its maximum soon after a lag period of 1 day and declined after 5 days. Treatment of splenic B cells from BALB/c mice with anti-Ly-1.2 antibody and rabbit complement resulted in a selective reduction of IgM RF production by 90%, with little effect of IgG RF production. These results suggest that IgG RF is derived primarily from CD5- memory B cells which have been developed in normal mice by an unknown mechanism. Unlike the CD5+ precursor cells for IgM RF, these memory cells are unresponsive to polyclonal stimulation by LPS but are activated by simultaneous stimulation by aggregated Fc epitopes and the mitogenic stimulus from LPS.

Animals↗
PubMed1990

Is Chiari I malformation in the aged initiated by mechanical factors? Report of three cases.

Three cases in which the signs and symptoms of Chiari I malformation were induced and worsened after the occurrence of supratentorial mass lesions are reported. The symptoms improved markedly after removal of the supratentorial lesions in these cases. In the first case, a meningioma in the right parietal region coexisted with Chiari I malformation. Although the cerebellar ataxia and nystagmus disappeared after tumor removal, decompressive surgery for the malformation was performed because of upper cervical nerve symptoms and the patient recovered completely. In the second case, the symptoms first occurred after a car accident, and a computed tomographic scan revealed not only a subdural hematoma, but also tonsillar herniation due to Chiari I malformation. After evacuation of the hematoma and decompressive surgery on the craniospinal junction, the symptoms disappeared. In the third case, the symptoms of malformation developed gradually with depression and gait disturbance. A meningioma in the left frontal region coexisted with Chiari I malformation. Although the symptoms improved remarkably after tumor removal, decompressive surgery on the craniospinal junction was performed because of upper cervical nerve symptoms, and the patient recovered completely. These clinical findings indicate that a supratentorial mass lesion may provoke the symptoms of Chiari I malformation in the aged.

Aged↗
PubMed1990

Hemangioblastomas of the central nervous system--immunohistochemical and ultrastructural study.

Immunohistochemical studies using immunoperoxidase staining for glial fibrillary acidic protein (GFAP), S-100 protein, and factor VIII-related antigen (VIII-RAg) were performed on 10 hemangioblastomas of the central nervous system to determine the origin of stromal cells. No cytoplasmic immunoreactivity for anti-GFAP, anti-S-100 protein, or anti-VIII-RAg was detected in most stromal cells. A small number of GFAP-positive cells were found only in the periphery of the tumor; they were thought to be trapped astrocytes or stromal cells taking up GFAP. Most stromal cells had abundant, clear cytoplasm with some microfilaments and lipid vacuoles. Cylindrical cytoplasmic processes and intermediate junctions were observed in some stromal cells, but most cells did not possess any junctional device. No stromal cell possessed any feature clearly suggesting endothelial cells or pericytes. Our immunohistochemical and ultrastructural investigations did not support the theories of stromal cell origin from astrocytes or endothelial cells. We concluded that stromal cells can be regarded as an aberrant cell type of angiogenic mesenchymal derivation.

Adolescent↗
PubMed1990

[The influence of volume expansion with induced hypertension on vessel reactivities, blood-brain-barrier, cerebral edema and infarction].

Eighteen anesthetized cats were randomly divided into 3 groups. One group was treated with 10 ml/kg of 6% hydroxyethyl starch (HES). Another group was treated with 15 ml/kg, and there was a control group. There were six cats in each group. Cerebral pial arterial reactivities were measured by means of intravital microscopic observation through a cranial window. Middle cerebral artery (MCA) was clipped for 70 minutes using a transorbital approach. Five hours later, Evans blue dye was injected intravenously and then the animals were killed. Administration of HES or Ringer's solution (control) was started 15 minutes before clipping of MCA. Systemic arterial pressure was elevated by using dopamine at the same time as the MCA occlusion was carried out. Pial arteries dilated soon after the clipping of MCA in all three groups, but showed different patterns in each group after recirculation of MCA. In the control group, they returned to 20% of their dilated state first, but, after about 4 hours, they redilated by 45% at the end of experiment periods. In the group treated with 10 ml/kg of 6% HES, they remained in an almost resting state after MCA recirculation, but in the group with 15 ml/kg, they constricted by 10% at the end of the experiment periods. Regarding the Evans blue dye extravasation, cerebral edema and infarction, they were largest in the control group. But animals treated with 15 ml/kg of 6% HES showed significantly larger Evans blue dye extravasation and cerebral edema than that of animals with 10 ml/kg. However cerebral infarctions were almost the same sizes in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Polymorphonuclear leukocyte-inhibitory factor of Bordetella pertussis. II. Localization in the outer membrane.

The outer and inner membranes and cytoplasm of spheroplasts of a strain of phase I B. pertussis were fractionated by density gradient centrifugation. The high density vesicles of the outer membranes isolated had the "Pili" characteristic of the bacteria and the same antigenicty as the bacterial surface. Activities for inhibition of polymorphonuclear leukocytes were also almost exclusively localized in this outer membrane fraction. The histamine-sensitizing activity was more dispersed, but its specific activity was also highest in the outer membrane fraction. These results suggest that molecules carrying these activities, which are probably different entities together with the tissue-adhesive pili, form a virulence complex on the surface of phase I organisms of B. pertussis.

Antigens, Bacterial↗
PubMed1978

Neuroradiologic evaluation of the subdural pathogenesis in infants with small heads.

A marginal low density area is often revealed by CT scan in infants with microcephalia. However, it is difficult to assess precisely the main pathologic state of the marginal low density area and also whether such a lesion exists in the subdural-epiarachnoid space or in the subarachnoid space. A carotid angiographic evaluation of cortical vessels in the marginal avascular area was made and suggestive results were obtained. When there is acute subdural effusion or subdural hematoma, cortical arteries in the marginal avascular area will have a straightened and attenuated figure. But when such a pathologic state persists for a long period, it induces secondary cortical atrophy and the subarachnoid space becomes enlarged. The cortical artery appears as if it is flying in the enlarged subarachnoid space because it is detached from the gyrus and the sulcus following the cortical atrophy. This is why we named it the 'flying artery.' Angiographic findings allow more precise interpretation of the marginal low density area in the CT scan.

Age Factors↗