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Biomedical subjects

K Kitamura

Publications and source records attributed to K Kitamura.

At least 991 records · Page 55Linked to original sources
PubMed1988

[Cerebral ischemia (1)--Reversibility of ischemic lesion and CT findings].

Two hundred and twenty-one patients with cerebral cerebral ischemic attack in the middle cerebral artery territory were investigated. Those patients manifested several clinical types, TIA: 31, stroke with full recovery: 50, minor completed stroke: 54 and major completed stroke: 86 cases. CT classification was made 3 weeks after the ischemic attack based on the characteristic arterial topography. We discussed in this paper what kind of ischemic lesion had greater possibility of recovery from ischemic lesion had greater possibility of recovery from ischemia focusing on the retrospective study of clinical symptoms, CT classification and angiographic findings. We also referred to the other factors influencing the reversibility of an ischemia such as lacunae and PVH (periventricular hypodensity). The extent of and LDA on CT scan closely correlated with clinical symptoms, CT classification and angiographic findings. We also referred to the other factors influencing the reversibility of an ischemia such as lacunae and PVH (periventricular hypodensity). The extent of an LDA on CT scan closely correlated with clinical types (Table 2). The reversibility of type I was excellent, however aged patients over 70 with PVH and ventricular dilatation developed permanent neurological impairment associated with dementia. The reversibility of a small infarction in the basal ganglia (type II) depended mainly on the involvement of the internal capsule. Infarction involving a cortex (type IV and type V) invariably resulted in permanent neurological deficits except for the rare cases with involvement of silent areas. CT classification of type III, so called demarcation zone infarction, developed various clinical types, and showed transient functional disturbance of the cortex without an infarction i the cortico-subcortical region.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Epidural hematoma without intradural lesions--clinical study of 120 cases].

One hundred twenty cases of epidural hematoma without intradural lesion treated between 1975 and 1983 to which CT scan was available, were presented. Mortality rate was 1.7% and morbidity rate was 6.7%. In all cases of epidural hematoma including with and without intradural lesion in the same term (164 cases), mortality and morbidity rate were 7.3 and 10.4% respectively. Ninety five cases were male and 25 cases were female. Causes of injury were falls from a height (42 cases, 35%), traffic accident (41 cases, 34%), and falls at ground level (24 cases, 20%). The site of hematoma in 120 cases of 128 hematoma were frontal (17 cases, 13%), temporoparietal (74 cases, 58%), parasagittal (4 cases, 3%), middle fossa (8 cases, 6%), occipital (16 cases, 13%) and posterior fossa (9 cases, 7%). Fractures were shown in 109 cases out of 120 cases on skull X-P and depressed fractures were 12 cases. Those which showed no fracture on skull X-P, revealed slow growth of hematoma and delayed onset of clinical signs and were mainly children. Seven operated cases of epidural hematoma does not show fractures on skull X-P nor initial unconscious. Clinical course of disturbance of consciousness were divided in five types as follows; I. no unconsciousness (22 cases, 18%), II. latent interval (17 cases, 14%), III. primary but no secondary unconsciousness (29 cases, 24%), IV. lucid interval (22 cases, 18%), V. unconscious throughout (16 cases, 14%) and unknown (14 cases, 12%). Cases which Glasgow Coma Scale Score were over 7 showed good recovery in Glasgow Outcome Scale.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[A study of continuous cerebrospinal fluid drainage in patients with subarachnoid hemorrhage].

The influences of continuous cerebrospinal fluid (CSF) drainage on vasospasm and hydrocephalus were analyzed retrospectively in 150 patients with subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysms (32 cases of grade 1, 85 cases of grade 2, and 33 cases of grade 3 by the Hunt and Hess classification). One hundred and seven of these cases received CSF drainage (cisternal, ventricular, lumbar, or a combination of these). The volume of CSF drainage within the first week after onset was 975 +/- 513 ml (mean +/- SD). The total volume of CSF drainage was 2063 +/- 1635 ml (mean +/- SD). The duration of CSF drainage was 10.6 +/- 6.8 days (mean +/- SD). Ten of 46 cases given no drainage within the first week after onset, nine of 55 cases with a drainage volume of less than 1000 ml within the first week, and 24 of 49 cases with a drainage volume of more than 1000 ml within the first week showed vasospasm. There was a statistically significant dose-response (drainage volume-vasospasm) relationship (p less than 0.005, Mantel extension method). Four of 43 cases with no drainage, 26 of 67 cases with a total drainage volume of less than 2000 ml, and 24 of 40 cases with a total drainage volume of more than 2000 ml developed hydrocephalus. There was a statistically significant dose-response (drainage volume-hydrocephalus) relationship (p less than 0.005, Mantel extension method). Vasospasm and hydrocephalus were statistically associated (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Electrophysiological and mechanical characteristics of histamine receptors in smooth muscle cells of the guinea-pig ileum.

To elucidate the role of the histamine receptor in functions related to intestinal motility, we investigated the effects of histamine and its antagonists on electrical and mechanical activities in longitudinal and circular layers of the terminal region of the guinea-pig ileum. Histamine hyperpolarized the membrane in the circular smooth muscle cells by increasing the permeability of K+ and it transiently inhibited generation of the spike while resting tone was elevated. Cimetidine (CIM) inhibited the hyperpolarization and relaxation induced by histamine while mepyramine (MEP) inhibited the contraction but did not affect the histamine-induced hyperpolarization. In the presence of CIM, histamine did not depolarize the membrane but did lower the threshold potential required for generation of the spike potential, increased the appearance of the spike and enhanced the phasic contraction. Histamine, in 20 mM K+ solution, hyperpolarized the membrane and produced a biphasic response, an initial relaxation and a subsequently generated contraction, in a concentration-dependent manner. In the longitudinal smooth muscle cells, histamine depolarized the membrane, and enhanced both generation of the spike and the contraction. MEP (0.1 microM) but not CIM (1 microM) blocked the histamine-induced responses. CIM at a higher concentration (10 microM) enhanced the histamine-induced contraction, while histamine did not relax the tissue precontracted by 20 mM K+. These results indicate that the circular muscle cells have both H1 and H2 receptors while the longitudinal muscle cells have the H1 receptor. The excitatory responses induced by activation of the H1 receptor in smooth muscle cells differ in these layers.

Animals↗
PubMed1987

Contrasuppressor cells that break oral tolerance are antigen-specific T cells distinct from T helper (L3T4+), T suppressor (Lyt-2+), and B cells.

Continuous gastric intubation of mice with the T cell-dependent antigen sheep erythrocytes (SRBC) leads to a state of systemic unresponsiveness to parenteral SRBC challenge, a state termed oral tolerance. The systemic unresponsiveness of mice rendered orally tolerant to SRBC, however, is converted to humoral immune responsiveness by adoptive transfer of effector T contrasuppressor (Tcs) cells. In this study, the authors have isolated and characterized the Tcs cell subset, from the spleens of orally immunized mice, which abrogates oral tolerance. This Tcs cell is a novel cell type, which can be separated from functional T suppressor (Lyt-2+) and T helper (L3T4+) cells, and the effector Tcs cell exhibits a Lyt-1+, 2-, L3T4- phenotype. Furthermore, contrasuppression is not mediated by B cells, including those of the Lyt-1+ phenotype. Adoptive transfer of splenic Lyt-1+, 2-, L3T4- T cells from C3H/HeJ mice given oral SRBC for 21 to 28 days and splenic Lyt-1+, 2-, L3T4- T cells of C3H/HeN mice orally immunized for a shorter interval abrogated oral tolerance. Furthermore, separation of Lyt-1+ T cells into L3T4+ and L3T4- subsets by flow cytometry resulted in Lyt-1+, L3T4+ T cells with helper but not contrasuppressor function, whereas the Lyt-1+, L3T4- T cell fraction abrogated oral tolerance even though it was without helper activity. This Tcs cell subset was also effective when added to cultures of tolerized spleen cells derived from SRBC-fed mice. The effector Tcs cells are antigen-specific, because Tcs cells from SRBC-immunized mice reverse tolerance to SRBC but not to horse erythrocytes (HRBC), and Tcs cells from HRBC-immunized mice reverse tolerance to HRBC but not to SRBC. When splenic T3 (CD3)-positive T cells (Lyt-1+, 2-, and L3T4-) were separated into Vicia villosa-adherent and nonadherent subpopulations, active contrasuppression was associated with the T3-positive and Vicia villosa-adherent T cell fraction. Thus, a distinct Lyt-1+, 2-, L3T4- T cell subset that contains a T3-T cell receptor complex, which can regulate oral tolerance, is present in spleens of orally immunized mice.

Administration, Oral↗
PubMed1987

Isolation of anti-idiotypic antibodies to T cells using an anti-framework determinant antibody.

A panel of anti-idiotypic antibodies to the T cell line HPB-ALL was produced by screening with a novel enzyme-linked immunoadsorption assay (ELISA). Using the beta framework I (beta F1) monoclonal antibody directed at a common determinant on the human T cell receptor beta subunit, we were able to specifically capture the receptor molecule from a cell lysate preparation and use this as the basis of an ELISA assay. Hybridoma supernatants were tested for their ability to bind to the receptor thus captured. A total of four antibodies were isolated by this method, and they were shown to immunoprecipitate a disulfide-linked heterodimer composed of alpha (49 kDa) and beta (40 kDa) subunits from HPB-ALL cells, similar to the subunits recognized by the beta F1 antibody. Furthermore, all four antibodies blocked the binding of T40/25, an anti-idiotype to HPB-ALL. Three of these antibodies blocked the binding of anti-Leu 4 to a similar degree as did T40/25, while one did not. This suggests that these new anti-idiotypic antibodies recognize distinct but associated idiotypic determinants. The isolation of such antibodies for any particular T cell line or tumor promises to be useful for biological studies of T cell malignancy in humans.

Animals↗
PubMed1987

Altered local cerebral glucose utilization induced by electrical stimulations of the thalamic sensory and parafascicular nuclei in rats.

Alterations in local cerebral glucose utilization (LCGU) induced by electrical stimulation of the sensory relay nucleus (VPL) or parafascicular nucleus (Pf) of the thalamus in conscious rats were measured by the [14C]2-deoxyglucose method, the objective being to assess the mechanism of analgesia induced by electrical stimulations of these structures. Stimulation of the VPL induced an ipsilateral increase in LCGU in the sensory thalamic nucleus itself, the sensory cortex and substantia nigra. Stimulation of the Pf induced bilateral increases in LCGU in the Pf and central medial nucleus of the thalamus, sensory cortex, ventral areas of the striatum and substantia nigra, and ipsilateral increase in LCGU in the periaqueductal gray, parabrachial pontine nucleus and deep layers of the superior colliculus. No significant change in LCGU was detected in the raphe dorsalis, raphe magnus and spinal dorsal horn, in both groups. Our observations coincide with clinical findings that unilateral electrical stimulation of the Pf leads to amelioration of intractable pain bilaterally, while that of the VPL induces an analgesia restricted to the contralateral side.

Animals↗
PubMed1987

Complete amino acid sequence of PO protein in bovine peripheral nerve myelin.

The P0 protein is a major structural glycoprotein of molecular weight 28,000 in peripheral nerve myelin. The complete amino acid sequence of bovine P0 protein was determined. The polypeptide chain consists of 219 amino acid residues and includes a highly hydrophobic domain (residues 125-150) in the middle, which probably represents a transmembrane segment. The amino terminal domain (residues 1-124) is relatively hydrophobic, but contains a negatively charged carbohydrate chain at Asn93. This domain is most likely located on the extracellular side of the membrane and may contribute to formation of the myelin intraperiod line by hydrophobic and electrostatic interactions. On the other hand, the basic carboxyl-terminal domain (residues 151-219) may protrude from the cytoplasmic side of the membrane and is probably involved together with basic proteins in the formation of the major myelin dense line through electrostatic interaction with acidic lipids in the membrane. The few interspecies amino acid variations between the bovine P0 and the rat P0 sequences, deduced from the cDNA (Lemke, G., and Axel, R. (1985) Cell 40, 501-508), indicate that the P0 protein is conserved across species.

Amino Acid Sequence↗
PubMed1987

Idiotype vaccination against murine B cell lymphoma. Inhibition of tumor immunity by free idiotype protein.

A murine B cell lymphoma (38C13) was used as a model to study the induction of idiotype (Id)-specific tumor immunity. Immunization of syngeneic mice with Id protein derived from the tumor resulted in the production of anti-Id antibodies by the host and in the induction of a state of resistance to tumor growth. Tumor immunity could be established only if the Id protein was conjugated to a strongly immunogenic carrier protein such as keyhole limpet hemocyanin or thyroglobulin, and if the conjugate was administered at least 1 week prior to tumor challenge. Free Id protein, such as that present in tumor bearing animals, was found to inhibit tumor immunity in a dose-dependent manner. Although tumor immunity could be induced in animals with pre-existent serum Id protein, the expression of the immune state was inhibited by the presence of the soluble protein.

Adjuvants, Immunologic↗
PubMed1987

The mechanism of activation of heart fructose 6-phosphate,2-kinase:fructose-2,6-bisphosphatase.

Partially purified fructose-6-P,2-kinase:fructose-2,6-bisphosphatase from beef heart was phosphorylated by cAMP protein kinase. The phosphorylated fructose-6-P,2-kinase shows lower Km for Fru-6-P (43 versus 105 microM) and for ATP (0.55 versus 1.3 mM) but no change in the Vmax, compared to those for unphosphorylated enzyme. There was no detectable change in Km or Vmax of fructose-2,6-bisphosphatase activity by the phosphorylation. These changes in heart fructose-6-P,2-kinase were in direct contrast to previous results for the liver isozyme in which phosphorylation led to inhibition of the kinase activity and activation of the phosphatase activity.

Animals↗