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Biomedical subjects

K Toda

Publications and source records attributed to K Toda.

At least 199 records · Page 11Linked to original sources
PubMed1990

An ultrastructural study of pulmonary capillary vessels in blood volume-overloaded rat.

Blood volume overload to pulmonary capillaries was experimentally induced by arterio-venous fistula between the left common carotid artery and the left external jugular vein in 42 S-D rats. The animals were sacrificed 1,2,4,8 and 24 weeks after the operation. Just after anastomosis, blood flow index of the shunted rats was about 4 times larger than in the controls and the high value was kept throughout the experiment (p less than 0.05). The relative right ventricular weight was about 1.5 times larger than in the controls (p less than 0.05). The capillary endothelium of the alveolar septum showed nuclear enlargement, swelling of the cytoplasm with microvillous projection, and increases of pinocytotic vesicles and microfilaments. In some cases, focal edema was seen accompanied with an increase of immature stromal cells. The basement membrane showed vague in contour in edematous area, especially in the epithelial side of the alveolar septum. These changes appeared most predominantly in 2 weeks and subsided almost completely in 24 weeks. Number of endothelial nucleus of the shunted rats increased significantly in 2 and 4 weeks and was normalized in 24 weeks. The surface area and volume of the capillaries also increased significantly in 2 and 4 weeks of the shunted animals. These findings showed that the capillary endothelium reacted and then was adapted to the blood volume overload.

Animals↗
PubMed1990

A method for removal of toxic chromium using dialysis-sac cultures of a chromate-reducing strain of Enterobacter cloacae.

A method for removal of toxic hexavalent chromium (chromate: CrO2-4) was developed by use of dialysis-sac cultures of a chromate-reducing strain of Enterobacter cloacae (HO1). E. cloacae strain HO1 cells were put in dialysis (semipermeable membrane) sacs, and the sacs were submerged in water containing toxic CrO2-4. The dialysis sacs allowed CrO2-4 to diffuse into the culture, and CrO2-4 was reduced anaerobically in the dialysis sacs by the E. cloacae cells. Because reduced chromium readily formed insoluble chromium hydroxides in the dialysis sacs, the greater part of reduced chromium was unable to diffuse out through the semipermeable membrane. Thus the dialysis culture of E. cloacae strain HO1 could successfully remove toxic chromium from the surrounding water. If the initial concentration of CrO2-4 was less than 4 mM (208 ppm as chromium), about 90% of the total chromium could be removed from water by the described method.

Bacteriological Techniques↗
PubMed1990

An analysis of histaminergic efferents of the tuberomammillary nucleus to the medial preoptic area and inferior colliculus of the rat.

The efferent projections of the five histaminergic neuronal subgroups in the tuberomammillary nucleus to the medial preoptic area (MPO) and inferior colliculus (IC) were examined by immunocytochemistry with antihistidine decarboxylase (HDC) antibodies combined with retrograde axonal tracing with Fast Blue (FB). The term "E groups" were used for the histaminergic neuronal subgroups. About 10% of the HDC-immunoreactive (HDCI) neurons were retrogradely labeled after FB injection into the MPO. The labeled neurons were not concentrated in any particular area, but were diffusely distributed bilaterally in all the subgroups. About two-thirds of the labeled neurons were observed on the side ipsilateral to the injection site and one-third on the contralateral side. The percentages of labeled neurons (double-labeled neurons/HDCI neurons) in the five subgroups were not significantly different with each other. The percentages in group E1 and E2 were particularly close, while that in group E4 resembled that in group E5. About 4% of the HDCI neurons were retrogradely labeled after the dye injections into the IC, and about half of the labeled neurons were detected on the ipsilateral side. The percentage of the double-labeled neurons in the five groups were not significantly different. Furthermore, those in E1 and E2, and in E4 and E5 were almost identical, respectively, to the situation following injection of FB into the MPO. These results indicate that each subgroup of histaminergic neurons in the tuberomammillary nucleus has similar efferent projections to the MPO and IC.

Animals↗
PubMed1990

Ultraviolet radiation suppresses mouse-ear edema induced by topical application of arachidonic acid.

The effect of ultraviolet (UV) radiation on arachidonic acid (AA) cascade was examined using an in vivo model. Mouse ear lobes were painted with 1 mg AA, and the maximum response of ear swelling was measured 1 h after challenge. Arachidonic-acid-induced ear swelling was significantly suppressed by preexposure to topical psoralen plus noninflammatory doses of long-wave UV radiation (PUVA) or middle-wave UV (UVB) radiation. Ultraviolet radiation may interfere with AA pathways to suppress ear swelling since AA-induced ear swelling is considered to be mediated by metabolites derived from exogenous AA. The results may relate to the therapeutic mechanisms of UV radiation in psoriasis in which the eicosanoid cascade is involved.

Administration, Topical↗
PubMed1990

Biooxidation of a synthetic waste by a microbial film grown on the liquid surface in a shallow flow reactor.

A new process of biological waste treatment was developed by use of microbial films grown on the liquid surface in a shallow flow reactor. The performance of this process was tested using a synthetic waste that contained acetic acid as a model organic pollutant. About 90% of acetic acid (10,000 mg/L-1) in the synthetic waste was removed by setting alpha tau: (alpha specific liquid surface area, cm-1, and tau: hydraulic liquid detention time, h) higher than 15 cm-1/h. It was necessary to maintain alpha large enough (more than 10 cm-1 in most cases) to satisfy oxygen demand for the biooxidation. The oxygen balance and TOC determinations showed that the acetic acid removed was completely oxidized with oxygen transferred through the liquid surface. This process would contribute to energy savings, since it requires no forced aeration for oxygen supply.

Acetates↗
PubMed1990

Lysosulfatide (sulfogalactosylsphingosine) accumulation in tissues from patients with metachromatic leukodystrophy.

We describe here a sensitive assay method for lysosulfatide (sulfogalactosylsphingosine) in human tissues using HPLC. The method involves extraction of lipids, saponification, isolation using a C18 Sep-Pak column, derivatization with o-phthalaldehyde, and detection of the fluorescent lysosulfatide using HPLC. In control subjects, a small amount of lysosulfatide was detected in the cerebral white matter (9-35 pmol/mg of protein), spinal cord (35 pmol/mg of protein), sciatic nerve (14 pmol/mg of protein), and kidney (approximately 2 pmol/mg of protein) but not in the cerebral gray matter and liver. A marked accumulation of the lipid was noted in tissues from six patients with metachromatic leukodystrophy (MLD). The concentration of lysosulfatide was high in the cerebral white matter, spinal cord, and sciatic nerve (223-1,172 pmol/mg of protein). Even in the cerebral gray matter, kidney, and liver, where lysosulfatide was hardly detected in the control sample, a considerable amount (3-45 pmol/mg of protein) accumulated in MLD patients. The concentration and distribution pattern of lysosulfatide were similar to those of galactosylsphingosine (psychosine) accumulated in patients with Krabbe disease. Therefore, the accumulation of lysosulfatide may explain the demyelination in patients with MLD, as is the case with Krabbe disease.

Cerebroside-Sulfatase↗
PubMed1990

Membrane-associated chromate reductase activity from Enterobacter cloacae.

Washed cells of Enterobacter cloacae HO1 reduced hexavalent chromium (chromate: CrO4(2-) anaerobically. Chromate reductase activity was preferentially associated with the membrane fraction of the cells. Right-side-out membrane vesicles prepared from E. cloacae cells showed high chromate reductase activities when ascorbate-reduced phenazine methosulfate was added as an electron donor.

Cell Membrane↗
PubMed1990

In vitro anticolon antibody production by mucosal or peripheral blood lymphocytes from patients with ulcerative colitis.

Serum anticolon antibody and in vitro anti-colon antibody production by peripheral blood and mucosal lymphocytes was investigated in patients with ulcerative colitis. The frequency of serum anticolon antibody was 71% in 41 patients with ulcerative colitis, estimated by enzyme linked immunosorbent assay (ELISA) using isolated rat colon epithelial cells. This finding confirms our previous report on the frequency of serum anticolon antibody detected by flow cytometry analysis. The estimated frequencies of IgG anticolon antibody secreting cells were 1.5-12.5/10(6) cells in the colonic mucosa and 0.1-0.5/10(6) cells in peripheral blood, from patients with ulcerative colitis when Epstein-Barr virus (EBV) was used as a B cell polyclonal activator. Poisson analysis of limiting dilution culture showed that about one per 140 IgG cells in the colonic mucosa synthesised anticolon antibody. Two monoclonal IgG antibodies were obtained from EBV transformed anticolon antibody secreting cells by limiting dilution method. One reacted with goblet cells in the intestine, and the other reacted mainly with colonic epithelial cells. These results suggest that heterogeneous anticolon antibodies are present in patients with ulcerative colitis and that colonic mucosa may be the main source of anticolon antibody. Local autoimmune reaction might have an important role in causing the inflammation of colonic mucosa in this disease.

Antibody-Producing Cells↗
PubMed1990

Activation of human keratinocyte migration on type I collagen and fibronectin.

The purpose of our studies was to learn more about the regulation of keratinocyte migration. Human keratinocytes freshly harvested from skin were relatively immotile cells, whereas keratinocytes harvested from cell culture migrated on type I collagen or fibronectin as measured in a phagokinesis assay. Development of migratory competence by keratinocytes varied depending on the culture substratum. Cells cultured on plastic were activated more quickly and to a greater extent than cells cultured on dermis. The effect of the culture substratum on migratory competence was reversible. That is, cells cultured on plastic showed reduced activity after subculture on dermis. Cells cultured on dermis showed increased activity after subculture on plastic. Freshly isolated as well as cultured keratinocytes contained beta 1 integrin subunits, but only cultured cells were able to organize the subunits into focal adhesions. These adhesion sites also contained vinculin. In epidermal explants, beta 1 integrin subunits were mostly in basal cells, often more prominent between lateral cell borders than at the epidermal-dermal interface. In keratinocytes that migrated out of skin explants, there appeared to be an increase in the intensity of beta 1 integrin subunit immunostaining, possibly because of the change in shape of migrating cells. Also, beta 1 integrin subunits were found around and beneath migrating keratinocytes. These results show that changes in the distribution of beta 1 integrin subunits accompany development of migratory competence.

Cell Adhesion↗
PubMed1990

Periventricular lucencies on computed tomography in multiple cerebral infarcts: correlation with cerebral blood flow measurements.

Forty-nine patients with multiple cerebral infarcts with a mean age of 70.2 years were studied to elucidate the effect of periventricular lucencies (PVLs) on cerebral blood flow (CBF). Patients with multiple cerebral infarcts showed significantly lower mean cortical blood flow (F1) values compared to 15 age-matched normal subjects (p less than .01). The mean F1 values were most significantly decreased in severe group of PVLs and moderately decreased in moderate and mild groups (p less than .05 between severe and mild groups); however, no significant differences in mean F1 values were found between severe and moderate groups. Demented patients showed significantly lower F1 values compared to nondemented patients (p less than .001) and normal subjects (p less than .001). There was no significant difference in the degree of PVL between demented and nondemented groups. As well, the mean F1 values were not significantly correlated with either the number of infarcts or ventricular dilatation. These results suggest that PVLs on CT (especially in severe cases of PVLs) may have some role in the reduction of cortical blood flow in patients with multiple cerebral infarcts.

Aged↗
PubMed1990

[Intra-arterial infusion chemotherapeutic effect of stage III breast cancer by survival rates].

Between January 1977 and December 1989, 140 patients of Stage III breast cancer were treated in Sapporo Medical College. Sixty-six of these patients received intra-arterial infusion chemotherapy. The anticancer drugs were mainly given by two routes, infusion into the internal mammary artery and the subclavian artery. Continuous infusion of 5-FU and intermittent injections of ADR, MMC, 4'-epi-ADR or THP-ADR were jointly or individually made in each artery. The 5-and 10-year overall survival rates were: infusion group 49.2% and 49.2%, non-infusion group 64.0% and 45.0%, respectively. Intra-arterial infusion chemotherapy seems to be useful because non-infusion group contained mostly Stage IIIa and conversely the infusion group contained mostly Stage IIIb. A significant difference was seen between 5-FU infusion group and MMC.ADR group (p=0.026). MMC group, MMC + ADR combination group and 4'-epi-ADR group were marginally significantly different in terms of survival rates of the anticancer drugs of Stage IIIb.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Inflammatory bowel diseases and thymus disorder: reactivity of thymocytes with monoclonal antibodies.

Thymectomy is one of the most effective means of treating myasthenia gravis (MG). Formation of lymphoid follicles in the thymus is seen at high rate in ulcerative colitis (UC) as well as MG. We examined the subsets of lymphocytes in the thymuses taken from patients with inflammatory bowel diseases (IBD), using OK series monoclonal antibodies. Decreases in OKT8 (CD8)-, 6(CD1)- and 10-positive cells and an increase of IA1-positive cells were observed in UC. In contrast, there were no significant changes in Crohn's disease (CD). Therefore, the thymocytes from UC appear to consist of comparatively matured cells under the influence of thymic hormone.

Adult↗
PubMed1990

[Cerebral blood flow and event-related potential in patients with cerebral infarction].

Cerebral blood flow (CBF) and P 300, a long-latency positive component of the scalp-recorded event-related potential (ERP) associated with cognitive processing were investigated in patients with cerebral infarction to elucidate the relationship between CBF and cognitive function. Twenty-five patients with cerebral infarction with a mean age of 66.8 years were studied. ERP was recorded during auditory discrimination tasks. The latency of the P 300 from Pz region was recorded. The regional CBF was measured by the 133Xe inhalation method. The F1 (cortical gray matter flow) values were calculated using the Obrist's method. The mean F1 values in patients with cerebral infarction were significantly lower compared to the values obtained for the 15 control subjects (mean age, 68.4 years) (p less than 0.01). Patients with cerebral infarction showed significant prolongation of the P 300 latency compared to the 20 control subjects (mean age, 64.4 years) (p less than 0.02). There was a significant correlation between the P 300 latency and the mean F1 values in patients with cerebral infarction (p less than 0.01). Present results suggest that the cognitive impairment with respect to ERP may be related to the reduction of cortical blood flow in patients with cerebral infarction.

Aged↗
PubMed1989

Structure and expression of elongation factor 2 gene during development of Dictyostelium discoideum.

A cDNA library constructed from poly(A)+ RNA isolated from Dictyostelium discoideum cells at 12 h of development was screened with the hamster elongation factor 2 (EF-2) cDNA. Several different cDNA clones which hybridized were isolated after a second screening. A cDNA clone representing the 5'-end of the mRNA was obtained by primer extension. By comparing the amino acid sequence deduced from the nucleotide sequences of these clones with that of hamster EF-2, we found enough homology between them to conclude that the isolated clones were complementary to the mRNA of D. discoideum EF-2. The N terminus which is the GTP-binding domain and the C-terminal half where it interacts with a ribosome showed a high degree of homology. The amino acid sequence of the carboxyl half includes that it contain a site of ADP-ribosylation by diphtheria toxin. From the Northern blotting analysis, the size of the mRNA was estimated to be 2.6 kilobases. The expression of the mRNA was high in vegetative cells, became maximal at the aggregation stage, and decreased thereafter through development. Upon differentiation of prespore and prestalk cells, the mRNA was highly enriched in the former over the latter. ADP-ribosylation assay of EF-2 protein by diphtheria toxin showed nearly the same developmental changes for the protein as the mRNA. However, prestalk cells were found to contain the same amount of the protein as prespore cells. The Southern blot analyses indicated that the gene encoding EF-2 is unique.

Amino Acid Sequence↗
PubMed1989

Alternative usage of different poly(A) addition signals for two major species of mRNA encoding human aromatase P-450.

Two cDNA clones for human placental aromatase P-450 (P-450AROM) have been isolated and sequenced. The insert of one clone (2894 bp) contains an open reading frame encoding a protein consisting of 503 amino acid residues together with a 49 bp 5'-untranslated stretch and a 1336 bp 3'-noncoding region to which a poly(A) tract is attached. Three potential poly(A) addition signals are detected in this 3'-noncoding region. The other clone contains a shorter cDNA insert, the nucleotide sequence of which overlaps with most of the sequence of the longer cDNA insert (nucleotides 36-2355) except for one nucleotide substitution. The 3'-noncoding region of this shorter cDNA is only 846 bp in length but a poly(A) tract is also attached to its 3'-terminus. Northern blot analysis of human placental RNA reveals the presence of two major mRNA species of 3.4 and 2.9 kb when probes excised from the overlapping region of these two cDNAs are employed. The 2.9 kb mRNA is not detected, however, when a fragment of the non-overlapping region of the longer cDNA is used as a probe. It is therefore concluded that the two major species of P-450AROM mRNA are formed as a consequence of alternative processing of precursor mRNA(s).

Amino Acid Sequence↗