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Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 415 records · Page 23Linked to original sources
PubMed1990

Portions of basement membrane with decreased negative charge in various glomerulonephritis.

The decrease in negative charge was evaluated in different portions of the basement membrane as well as the lamina rara externa (LRE) and lamina rara interna (LRI). The subjects were nine patients [2 patients with focal segmental glomerulosclerosis (FGS), 2 with membranoproliferative glomerulonephritis (MPGN), 3 with IgA nephropathy, and 2 with Henoch-Schoenlein purpura nephritis (HSPN)] and 2 patients with minor glomerular abnormalities and 1 with tubulo-interstitial nephritis (TIN) as controls. Polyethyleneimine (PEI) was used as a cationic probe. The basement membrane was divided into the peripheral portion (loop basement membrane 7 microns or more from the anchor portion), proximal portion (within 3 microns of the anchor portion), and the paramesangial portion in the paramesangial basement membrane. In each portion, PEI granules per 1 micron of the LRE and LRI were counted. Anionic sites were decreased in the patients with FGS and MPGN, but the damage pattern differed between the two diseases. In the patients with FGS, the decrease in anionic sites was most marked in the peripheral portion with an even greater decrease in the LRI. In the patients with MPGN, the decrease was uniform among the portions. On the other hand, no significant difference was observed in any portion between the patients with IgA nephropathy or HSPN and the controls. The portions with decreased negative charge varied among various glomerular diseases, suggesting different developmental mechanisms.

Adolescent↗
PubMed1989

Inhibitory effects of newly synthesized sulfonamide derivatives on calmodulin-dependent phosphodiesterase activity and their modulation of the external ATP-dependent permeability change in mammalian cultured cells.

External ATP causes a passive permeability change in several types of transformed cells and this change is further enhanced by calmodulin antagonists, such as trifluoperazine. However, such drugs also have nonspecific effects on membrane permeability. We have synthesized several new sulfonamide derivatives, which were found to inhibit calmodulin-dependent phosphodiesterase. The drugs also enhanced the ATP-dependent permeability change in CHO-K1 cells, but their effective concentration ranges were wider than those of previously known antagonists, and thus they would be useful for pharmacological use.

Adenosine Triphosphate↗
PubMed1989

Raman/absorption simultaneous measurements for cytochrome oxidase compound A at room temperature with a novel flow apparatus.

A novel flow apparatus for continuously producing reaction intermediates of cytochrome oxidase was constructed and applied successfully to observe the transient absorption and resonance Raman spectra in its reaction with oxygen. Time-resolved difference absorption spectra in 500-650-nm region clearly indicated the formation of compound A upon photolysis of the fully reduced CO-bound form at 5 degrees C, and at this stage electrons were not transferred from cytochrome c to cytochrome oxidase. However, at the stage of formation of compound B, cytochrome c was oxidized. Resonance Raman spectra of these intermediates measured simultaneously with the absorption spectra are also reported.

Absorption↗
PubMed1989

Analytical studies on beta-lactam antibiotics. III. Automated high-performance liquid chromatographic method for the determination of the orally active antibiotic ceftibuten in human plasma and urine.

A fully automated high-performance liquid chromatographic method was established for the determination of the oral cephalosporin antibiotic ceftibuten. The procedure for plasma assay involves on-line sample clean-up with a precolumn of BSA-ODS (ODS coated with bovine serum albumin) and subsequent determination of the drug with a reversed-phase C18 column using a column-switching technique. The precolumn effectively removed protein components and hydrophilic substances from plasma, with ceftibuten and its metabolite, the trans-isomer of ceftibuten, being retained using an ion-pairing reagent, tetra-n-butylammonium bromide, in the mobile phase. In urine assay, an ODS precolumn was used in place of the BSA-ODS column. The urine sample, after 10-fold dilution, was analysed in a similar manner to that used in the plasma assay. A large proportion of hydrophilic substances was eliminated by the on-line clean-up and the residual interfering substances introduced into the analytical column were separated from ceftibuten and its metabolite using the ion-pairing reagent. This method permits the determination of 0.1-20 micrograms/ml of ceftibuten and its metabolite in human plasma and 1-200 micrograms/ml of both compounds in urine. The advantages of the method are easy performance without manual sample preparation, saving of plasma (50 microliters) and high sensitivity. The method was applied to pharmacokinetic studies of ceftibuten after oral administration to healthy subjects.

Administration, Oral↗
PubMed1989

Pulmonary sclerosing hemangioma of the lung. A type II pneumocytoma by immunohistochemical and immunoelectron microscopic studies.

Three cases of pulmonary sclerosing hemangioma were studied by immunohistochemical and immunoelectron microscopic methods using a panel of antibodies. Six cases of adenocarcinoma of the lung, three cases of normal mesothelium, and three cases of mesothelioma were used as controls. The cytoplasm of some of the sclerosing hemangioma tumor cells was positive for the anti-lung surfactant apoprotein monoclonal antibody (PE-10). These cells were the pale cells of the solid areas, the cells covering the papillary projections, and the cells lining the cleft-like spaces. These cells also were positive for conventional epithelial cell markers. Some cells also were positive for vimentin. Electron microscopic study showed that the predominant cell was a poorly differentiated pneumocyte. Immunoelectron microscopic study also demonstrated that PE-10 existed in the rough endoplasmic reticulum of some of the cells in the solid areas, in the same way as normal type II pneumocytes. We concluded that the sclerosing hemangioma is an epithelial tumor with differentiation towards type II pneumocytes.

Aged↗
PubMed1989

[Field localization and verification system for proton beam radiotherapy in deep-seated tumors].

It has been recognized that, for precise localization and verification of radiation fields, a marking drawn on the skin surface is not entirely reliable because its position relative to bony structures or internal organs is not stationary. This is especially true when treating deep-seated tumors located below the clavicle. In proton beam radiotherapy at the University of Tsukuba, we ristrict the margins around the target volume. Therefore, special care in field localization and verification is needed, and we make it a rule to take X-ray pictures on each treatment day. To accomplish this, we have developed a localize-and-verify system by using fluoroscopic techniques and combining it with a real-time digital image processing device. This allows for the formation of a digital image of the proton field and storage it in the optic disc. By using this system as well as verification films, filed placement errors were measured in 10 patients with deep-seated tumors. Out of a total of 190 localizations, 22% exhibited a field placement error of more than 5 mm, where patient positioning and field localization were done by using skin drawings aligned with laser beams. This result strongly suggests the necessity for daily localization and verification of radiation fields, as is being done by us, for precision in the execution of proton beam radiation therapy.

Adult↗
PubMed1989

Resonance Raman characterization of hog thyroid peroxidase. An SERRS study.

Resonance Raman (RR) spectra of hog thyroid peroxidase (TPO) were observed for the first time and compared with those of lactoperoxidase (LPO) and horseradish peroxidase (HRP). Since TPO purified by monoclonal antibody-assisted immunoaffinity chromatography was strongly fluorescent, the surface enhancement technique using Ag colloid adsorption was used for the oxidized form, but ordinary RR spectra could be obtained for the reduced form. The RR spectra of TPO were distinct from those of HRP in both the oxidized and reduced states and indicated the presence of six-coordinated iron-protoporphyrin.

Animals↗
PubMed1989

Effects of ONO-3708, an antagonist of the thromboxane A2/prostaglandin endoperoxide receptor, on platelet aggregation and thrombosis.

The beneficial effects of an antagonist of the thromboxane A2/prostaglandin endoperoxide receptor, 7-[2 alpha,4 alpha-(dimethylmethano)-6 beta-(2-cyclopentyl-2 beta- hydroxyacetamido)-1 alpha-cyclohexyl]-5(Z)-heptenoic acid (ONO-3708) on thrombosis were examined. ONO-3708 at 0.1-3 microM inhibited the human platelet aggregation induced by thromboxane A2, prostaglandin H2, collagen, ADP (secondary phase) and epinephrine (secondary phase) without affecting prostanoid synthesis and the content of cyclic AMP in platelets. The in vivo effects, on coronary thrombosis in this case, were examined in two canine models. ONO-3708, 3 to 300 micrograms/kg i.v., prevented dose dependently the coronary thrombosis induced by partial obstruction of the coronary artery. ONO-3708, 3 micrograms/kg per min i.v., significantly prevented electrically stimulated coronary thrombosis without affecting systemic blood pressure and heart rate. These results indicate that the thromboxane A2/prostaglandin endoperoxide receptor could play an important role in the pathogenesis of thrombosis and that ONO-3708 may have therapeutic advantages in preventing thrombosis.

Animals↗
PubMed1989

Regulation of glucose transport activity and expression of glucose transporter mRNA by serum, growth factors and phorbol ester in quiescent mouse fibroblasts.

We have investigated the effects of growth factors such as serum, platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) on glucose transport activity in quiescent mouse Swiss 3T3 cells. DNA synthesis was synchronously induced by either calf serum, or platelet-poor plasma in combination with PDGF or FGF. Early stimulation of glucose transport in the quiescent cells was also caused by serum, or by either PDGF or FGF. The time courses for the stimulation of transport were identical for serum, PDGF and FGF, and the stimulated uptake in each case was associated with a 5-6-fold increase in Vmax. There were no detectable changes in apparent Km. Expression of glucose transporter mRNA was also enhanced by these growth factors. By contrast, EGF, insulin and platelet-poor plasma had little effect on glucose transport and transporter-gene expression, although uridine uptake was enhanced by all of these growth factors. These results suggest that cell cycle-dependent stimulation of glucose transport and expression of the transporter mRNA are regulated by a specific class of growth factors such as PDGF and FGF. The tumor promoter phorbol 12-myristate 13-acetate (PMA) also stimulated glucose transport and expression of transporter mRNA in quiescent 3T3 cells. These stimulations were absent in PMA-pretreated cells. However, serum, PDGF and FGF were able to stimulate glucose transport as well as expression of the transporter mRNA in PMA-pretreated cells, suggesting that there are at least two independent pathways for regulating glucose transport and glucose transporter mRNA level in quiescent fibroblasts.

Animals↗
PubMed1989

Characteristics in tyrosine coordinations of four hemoglobins M probed by resonance Raman spectroscopy.

Resonance Raman spectra of four hemoglobins (Hbs) M with tyrosinate ligand, that is, Hb M Saskatoon (beta distal His----Tyr), Hb M Hyde Park (beta proximal His----Tyr), Hb M Boston (alpha distal His----Tyr), and Hb M Iwate (alpha proximal His----Tyr), were investigated in order to elucidate structural origins for distinctly facile reducibility of the abnormal subunit of Hb M Saskatoon in comparison with other Hbs M. All of the Hbs M exhibited the fingerprint bands for the Fe-tyrosinate proteins around 1600, 1500, and 1270 cm-1. However, Hb M Saskatoon had the lowest Fe-tyrosinate stretching frequency and was the only one to display the Raman spectral pattern of a six-coordinate heme for the abnormal beta subunit; the others displayed the patterns of a five-coordinate heme. The absorption intensity of Hb M Saskatoon at 600 nm indicated a transition with a midpoint pH at 5.2, whereas that of Hb M Boston was independent of pH from 7.2 to 4.8. The fingerprint bands for the tyrosinate coordination as well as the Fe-tyrosinate stretching band disappeared for Hb M Saskatoon at pH 5.0, and the resultant Raman spectrum resembled that of metHb A, while those bands were clearly observed for Hb M Boston at pH 5.0 and for two Hbs M at pH 10.0. These observations suggest that the unusual characteristics of the heme in the abnormal beta chain of Hb M Saskatoon result from the weak Fe-tyrosinate bond, which allows weak coordination of the proximal histidine, giving rise to the six-coordinate high-spin state at pH 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemoglobin A↗
PubMed1989

Immortal epithelial cells of normal C3H mouse liver in culture: possible precursor populations for spontaneous hepatocellular carcinoma.

Long-term culture of primary hepatocytes derived from normal young male C3H/HeNJclMTV+ (C3H) and C57BL/6NJcl (C57) mice, respectively known for very high and low incidences of spontaneous hepatoma, resulted in development of multiple slowly growing epithelial colonies in the C3H case, the number of colonies being increased five-fold when 1.5 mM phenobarbital was added to the culture medium. On the other hand, the primary culture cells from C57 mouse liver gave rise to such epithelial colonies only very rarely, even with phenobarbital. Immunohistochemical investigation revealed alpha-fetoprotein and/or albumin production by the colony cells and ultrastructural analysis also revealed some hepatocytic features in them. Subculturing of individual colonies gave rise to cell lines which could be repeatedly passaged. Two of five lines implanted into athymic nude mice manifested tumorigenicity, the resultant neoplasms being diagnosed as a trabecular hepatocellular carcinoma and an adenocarcinoma. The experimental data suggest that the colony-forming immortal epithelial cells possibly represent early phase precursors of spontaneous mouse hepatocellular carcinomas. This culture system is expected to be useful for future elucidation of the mechanisms underlying spontaneous mouse hepatocarcinogenesis.

Animals↗
PubMed1989

Type 1 (insulin-dependent) diabetes in Japanese children is not a uniform disease.

The initial course of Type 1 (insulin-dependent) diabetes mellitus was studied in two groups of Japanese children, i.e. 21 patients with abrupt onset (Group A) and 19 patients detected by urine glucose screening at school with minimal or no symptoms (Group B). There was no statistical difference in mean age at diagnosis between Group A and B (11 +/- 3 years vs 11 +/- 3 years). Group A patients revealed a rapid deterioration of pancreatic B-cell function, but there was evident recovery of the B-cell function from 3 to 9 months following initial treatment. The B-cell capacity in Group B was self maintained until 24 months after diagnosis. Thereafter, even these patients exhibited a progressive decline in the B-cell function. The two groups had a similar incidence of islet cell antibodies at diagnosis (58% vs 69%). However, human leukocyte antigen studies revealed that patients in Group A had a significantly higher prevalence of DR4 and DRW9 than those in Group B (p less than 0.01). These results suggest that in Japanese children there are two forms of diabetes, an abrupt and a slow onset form, which are clinically different and which also seemed to be genetically independent types, or possibly the same disease diagnosed at different stages.

Adolescent↗
PubMed1989

Instability of integrated hepatitis B virus DNA with inverted repeat structure in a transgenic mouse.

We established four cell lines, from the liver cells of a transgenic mouse, constructed with hepatitis B virus DNA that had an inverted repeat structure. The integrated DNA patterns of the four established cell lines were different from one another and from the original pattern. These data show that the instability of integrated hepatitis B virus DNA would also occur in somatic cells during replication, apart from meiosis, which was previously reported.

Animals↗
PubMed1989

Comparative study of diethylnitrosamine-initiated two-stage hepatocarcinogenesis in C3H, C57BL and BALB mice promoted by various hepatopromoters.

The comparative inducibility of enzyme-altered islands (EAIs) by diethylnitrosamine (DEN) and their responsiveness to hepatopromoters belonging to different classes were studied in C3H/HeN (C3H), C57BL/6N (C57) and BALB/cA (BALB) mice. Male mice were given an i.p. injection of DEN (20 micrograms/g body weight) after partial hepatectomy at 6 weeks of age and then fed either basal diet or diet containing phenobarbital (PB) (500 p.p.m.), clofibrate (CF) (1000 p.p.m.) or ethynyl estradiol (EE) (10 p.p.m.). The numbers and size distribution of EAIs were assessed after the mice were killed at week 20, utilizing stereological methods. In the groups receiving DEN but no promoter, the number and mean size of the lesions were far larger in the C3H mice than in the other strains. Under the promoting pressure of PB, the growth of EAIs in C3H and BALB were accelerated remarkably, but those of C57 mice only slightly. Interestingly, in BALB the number of EAIs was much fewer than those of C3H in spite of their good sensitivity to PB, suggesting that BALB was refractory to the initiation process by DEN. A promoting effect for CF could only be demonstrated for the C3H strain and EE as the dose used inhibited the development of EAIs in all the strains. The experimental data thus indicate that interstrain differences in two-stage hepatocarcinogenesis among mice with different genetical backgrounds may exist, either in initiation or promotion, or in both processes.

Animals↗
PubMed1989

A novel enzyme immunoassay for conidia of Fusarium oxysporum f.sp. cucumerinum F504.

This study was undertaken to develop a new tool to study fusarial diseases of plants. Micro- and macro-conidia of a strain (F504) of Fusarium oxysporum were isolated and antiserum against the conidia was elicited in rabbits. A highly specific and sensitive competitive-type enzyme-linked immunosorbent assay (ELISA) for conidia of the strain was developed using the antiserum with beta-D-galactosidase-labeled anti-rabbit IgG as the secondary antibody and conidia fragments of the strain as antigen attached to Amino-Dylark solid-phase balls. The assay was highly specific to conidia of the strain F504, while conidia-free hypha of the strain F504 as well as all other microorganisms tested including nine other strains of Fusarium species showed little cross-reactivity. Application of the ELISA to following the growth rates of conidia in hyphae of the strain F504 under several conditions are also reported.

Animals↗
PubMed1989

Modulation of immunological abnormalities of growth hormone-deficient children by growth hormone treatment.

We studied the immunomodulatory role of growth hormone (GH) treatment in GH-deficient children. GH potentiated natural killer (NK)-cell activity and the PHA and Con-A lymphocytoproliferative response. Two-color fluorescence using monoclonal antibodies (CD4, 2H4, CD8 and CD11) showed a moderate reduction of the helper T cells and NK cells, but no changes of suppressor T cells or cytotoxic T-cells during GH therapy. Cancer and slow viral infection in GH-deficient children have been watched for carefully before and after GH therapy.

Adolescent↗