Biomedical subjects

N Kubota

Publications and source records attributed to N Kubota.

At least 19 recordsLinked to original sources

PubMed1997

The effect of iodine-based contrast agents on the levels of radiation-induced chromosomal aberrations.

The effects of iodine-based contrast agents on the repair of radiation-induced chromosomal damage were investigated employing peripheral blood from a healthy male donor. The blood samples were irradiated with 0.5-4.0 Gy 137Cs gamma rays. Contrast agents and NaCl solutions of various concentrations were added to the blood within the first 15 min or at 60 min after irradiation, and the samples were subsequently cultured for 45 h at 37 degrees C. Significantly elevated frequencies of chromosomal abnormalities caused by postirradiation treatment with hypertonic contrast agents appeared to increase with increasing hypertonicity. Elevated aberration frequencies were found to be greatest in the samples treated within 15 min of irradiation. The contrast agents had little effect if they were added at 60 min after irradiation, probably because the process of chromosome rejoining had been completed. Isotonic iodine-based contrast agents did not enhance the frequencies of chromosomal aberrations to a significant degree.

Adult↗

PubMed1997

[Acute myeloid leukemia with monosomy 7 accompanied by central diabetes insipidus].

A 27-year-old female was diagnosed as having atypical aplastic anemia in 1979 because of hypercellular bone marrow with abnormal erythroblasts and megakaryocytes. Afterward the diagnosis was corrected to myelodysplastic syndrome (RA) due to the reevaluation of the bone marrow smears. In March, 1995, thirst and polyurea occurred. In April, 1995, bone marrow aspiration biopsy showed the proliferation of atypical blasts (28%), and two months later, the number of the blasts increased (30%) and leukemic progression was noticed. Only 0.5 percent of the blasts showed weak peroxidase activity, and most of the blasts had CD13, CD33 and several adhesion molecules as CD11a, CD11b, CD44, CD54 and CD56. Karyotype of the bone marrow cells was 45, XX, -7. Her polyurea was caused by central diabetes insipidus. She was also complicated by pleuritis, colon ulcer, sinusitis and hypothalamic dysfunction. The etiology of these signs was due to the leukemic cell infiltration. She died despite of receiving multi-drug chemotherapy.

Adult↗

PubMed1996

ACE-inhibitor-induced cough, an adverse drug reaction unrecognised for several years: studies in prescription-event monitoring.

OBJECTIVE. This study examines cough recorded in Prescription-Event Monitoring (PEM) of four ACE-inhibitors. Particular attention was paid to the study of enalapril because the drug was monitored before the causal relationship between cough and ACE-inhibitors had been widely accepted. RESULTS. Several factors which had obscured the causal relationship in the individual cases were found to be also an obstacle in PEM. For example, cough was a common and non-serious event and was under-reported in the PEM study of enalapril and the rate was not strikingly different from that recorded for other drugs. Cough induced by ACE-inhibitors has several characteristics which reduce the chance of a recognisable "signal'. The original questionnaires returned from doctors in the PEM study of enalapril have been reexamined. The observation that the rate of cough diminished after enalapril had been stopped rather than increased after starting, provided the best evidence of causality, because this was not affected by many biases such as the publicity that had occurred prior to doctors participating in PEM completed later reports.

Adult↗

PubMed1996

Clinical significance of LEA-1 expression in adult acute myeloid leukemia.

In this study, we examined expressions of several adhesion molecules (AdMs), i.e. leukocyte function antigen-1 (LFA-1: CD11a/CD18), Hermes homing receptor (CD44) and intercellular adhesion molecule-1 (ICAM-1: CD54), on leukemia cells from 51 adult patients with newly diagnosed acute myeloid leukemias (AMLs) to elucidate clinical significance of these AdM expressions. Those expressions in lymphoid malignancies have been correlated with tumor evolutions, but CD44 was detected in all the AML cases examined and CD54 expression did not associate with their clinical characteristics or outcomes. However, we found that LFA-1 expressions significantly correlated with splenomegaly, resistance to induction chemotherapies and short survival periods in AML patients.

Acute Disease↗

PubMed1996

Phosphorylated sites of M(r) 25,000 protein, a putative protein phosphatase 2A modulator, and phosphorylation of the synthetic peptide containing these sites by protein kinase C.

The M(r) 25,000 protein isolated from Xenopus laevis oocytes was shown to be an effective phosphate acceptor for Ca(2+)-phospholipid-dependent protein kinase (protein kinase C) [Hashimoto, E. et al. (1995) J. Biochem. 118, 453-460]. In this study, the sites of this protein phosphorylated by protein kinase C were determined and the mechanism of substrate recognition was studied using a synthetic peptide containing the phosphorylation sites. After incorporation of about 2 mol of phosphate per mol of this protein, the radioactive protein was digested with trypsin and the phosphopeptides were purified by a series of column chromatographies. The amino acid sequence of the major radioactive peptide was shown to be Ser-Arg-Val-Ser-Lys-Arg. This and previous results suggest that the two serine residues at the amino-terminal region were phosphorylated by protein kinase C. To confirm this, the phosphorylated protein was directly analyzed for the amino acid sequence. The percent distribution of dithiothreitol adduct of the phenylthiohydantoin derivative of serine (PTH-serine) compared with that of PTH-serine increased at the first and fourth cycles of the sequence analysis. When the synthetic peptide composed of the amino-terminal eleven amino acids was employed as phosphate acceptor, the Km value was unexpectedly high (1.1 mM) compared with that of the native protein (0.5 muM). A stimulatory effect of M(r) 25,000 protein on the activity of protein phosphatase 2A was further enhanced after phosphorylation by protein kinase C. These results suggest that the two serine residues recognized by protein kinase C may have some role in the regulation of this M(r) 25,000 protein.

Amino Acid Sequence↗

PubMed1996

Results of surgery for paralytic exotropia due to oculomotor palsy.

In 138 cases of paralytic exotropia due to oculomotor palsy, transposition of the superior oblique muscle and resection of the medial rectus muscle were carried out. Surgery was performed with or without recession of the lateral rectus muscle. The long-term prognosis for 4 years or more was observed in 35 cases. We found that the same results could be obtained by selecting transposition of the superior oblique muscle in cases of complete palsy and resection of the medical rectus muscle in cases of incomplete palsy. There was no benefit in combining resection of the medial rectus muscle when performing the transposition of the superior oblique muscle. Regardless of which method was used, a combination with recession of the lateral rectus muscle greatly improved the effectiveness of the procedure.

Adolescent↗

PubMed1996

The 69-84 amino acid region of the parathyroid hormone molecule is essential for the interaction of the hormone with the binding sites with carboxyl-terminal specificity.

We evaluated the competitive inhibitory effect of intact PTH, the amino-terminal PTH(1-34) fragment, and a series of truncated carboxyl-terminal PTH fragments on the binding of internally 35S-labeled human PTH(1-84) ([35S]hPTH(1-84)) to osteoblastic cells (ROS 17/2.8), in order to identify the minimum and critical elements within the PTH molecule for the interaction with the binding sites specific for the carboxyl-terminal region of the hormone. When the amino-terminal region of the PTH molecule was truncated stepwise, hPTH(35-84), hPTH(53-84) and hPTH(69-84), but not hPTH(70-84), significantly inhibited the [35S]hPTH(1-84) binding. On the other hand, the simple deletion of the carboxyl-terminal glutamine at position 84 of hPTH(53-84) [hPTH(53-83)] resulted in blunting the inhibitory effect of the peptide on the [35S]hPTH(1-84) binding. Furthermore, hPTH(35-84), hPTH(53-84) and hPTH(69-84), but not hPTH(70-84) nor hPTH(53-83), augmented the inhibitory effect of the amino-terminal PTH fragment [hPTH(1-34)] on the [35S]hPTH(1-84) binding. Of special interest was that the combination of hPTH(1-34) and hPTH(35-84) reproduced the inhibitory effect of unlabeled hPTH(1-84) on the [35S]hPTH(1-84) binding, on an equimolar basis. The 69-84 region of the PTH molecule thus appears to be crucial for binding to the carboxyl-terminal specific binding sites for PTH in osteoblasts. The interaction of the amino-terminal and carboxyl-terminal regions of a PTH molecule with their own respective binding sites seemed to occur in a fairly independent manner.

Alkaline Phosphatase↗

PubMed1996

[Structure and magnetic resonance imaging of the fiber connection between Whitnall's ligament and the superior wall of the orbit].

To confirm the structure of the fiber connection between Whitnall's ligament and the superior wall of the orbit, we observed ten orbits of five Japanese cadavers by magnetic resonance imaging (MRI) and dissection. Our findings were as follows: MRI showed a well-circumscribed low-intensity signal at the fiber connection. Preaponeurotic fat was prominent, and the fibers originating from Whitnall's ligament were fused at the lower face of the capsule of the preaponeurotic fat in four cadavers. The fibers originating from the upper face of the fat were attached to the superior periorbit (minimum width, 15 mm). The fifth cadaver had little preaponeurotic fat and few fibers. These anatomic differences may be within the normal range of variation. We believe that the fibers support Whitnall's ligament and help to retract preaponeurotic fat during levator muscle contraction as the eye opens.

Adipose Tissue↗

PubMed1996

Pollinosis etiologic relationship between excessive IL-4 production and down-regulation of the inflammation-suppressive system.

Previous findings suggest a bi-directional relationship between the immune and endocrine systems, which may expand to a major inflammation-regulatory mechanism, although its mechanism is largely unknown, especially in the human body. Lymphokine and neuroendocrine peptide hormones have been identified as two major groups of immunologic mediators. The particularly pivotal molecules among them are interleukin (IL-1), considered to be a mediator of inflammation, and ACTH, whose activation is induced by IL-1. Among the important functions of lymphokines related to atopic inflammation is the regulation of IgE secretion from B cell through the action of IL-4, produced from the Th2 subset stimulated by IL-1, as a switch factor. IL-4 is the major IgE secretagogue. IL-4 is, moreover, a potent suppressive stimulant of IL-1 secretion. In this study, we tested the hypothesis whether a immunologic interaction exists in patients with allergic rhinitis to Japanese cedar pollen. We performed immunohistochemical staining of IL-1 beta, interleukin 1 receptor (IL-1r) and interleukin-4 (IL-4) in the nasal tissue, and evaluated serum levels of the biochemical mediators involved in the inflammation-regulatory mechanism: IL-1 beta, IL-4, interleukin 1 receptor antagonist (IL-1ra), IgE, cortisol, and ACTH before, during, and after allergen-provoked rhinitis in pollinosis sufferers. Our morphological study showed that, even before the pollen season, large amounts of IL-4 and IL-1r, exclusive of IL-1 beta, were produced in the nasal tissue of patients with seasonal pollinosis. IL-1-positive cells were observed in small amounts in the same tissue, but the quantity was probably enough to cause secretion of intrinsic IL-4 to produce sufficient IgE for atopic inflammation. Upon immunoenzymatic measurement of serum IL-4, even before the pollen season, almost all atopic patients also showed a higher IL-4 level than controls. Serum IgE data also showed a high level before the pollen season in atopic patients. This evidence suggests that atopic patients have already set the first step of inflammatory event not only in the nasal epithelium but also generally even before inhaling proper quantity and quality of the allergen. On the other hand, although atopic patients had inflammation, they did not show an extremely high value of serum IL-1, regarded as inflammatory lymphokine, compared with non-atopic individuals. In contrast, a higher serum level of IL-1ra was observed before and during the pollen season in atopic patients, subsiding to normal level after the season. Serum levels of both cortisol and ACTH did not show a high value in atopic patients during the season. These results demonstrate that excessive IL-4 production of atopic patient causes down-regulated transformation of IL-1 and up-regulated secretion of IL-1ra generally, followed by failure to increase secretion of ACTH from hypophysis and cortisol generally, resulting in defective performance of a specifically useful function of the anti-inflammatory mechanism.

Adrenocorticotropic Hormone↗

PubMed1996

Results of surgery for paralytic esotropia due to abducens palsy.

The surgical effects of three methods, transposition of the vertical rectus muscles, Jensen's procedure, and resection (advancement) of the lateral rectus muscle, were compared among 109 cases of paralytic esotropia due to abducens palsy. These procedures were combined with recession of the medial rectus muscle in about half the cases. Of the 109 cases, 22 were followed up for 4 years or longer. Results were similar, provided that the following protocols for surgery were adhered to: in cases of complete paralysis, transposition of the vertical rectus muscles was done, and in cases of incomplete paralysis, resection (advancement) of the lateral rectus muscle was performed. With both procedures, results were improved if recession of the medial rectus muscle was carried out at the same time.

Abducens Nerve↗

PubMed1996

Long-term results of surgery for superior oblique palsy.

The results one month after surgery in 159 cases of superior oblique palsy were compared according to the method of surgery with the results 4 years or longer after surgery. There were 141 cases of congenital palsy and 18 cases of acquired palsy, for a total of 159 cases. Our study showed that surgery on the oblique muscle provided long-lasting effects, while recession of the superior rectus muscle or recession of the contralateral inferior rectus muscle could cause late overcorrection. When performing surgery on the rectus muscle, careful attention must be paid to suturing the muscle.

Humans↗

PubMed1995

Molecular cloning and expression of serum calcium-decreasing factor (caldecrin).

We previously reported on the purification of a serum calcium-decreasing factor, referred to as caldecrin, from porcine pancreas, that is thought to be a serine protease (Tomomura, A., Fukushige, T., Noda, T., Noikura, T., and Saheki, T. (1992) FEBS Lett. 301, 277-281). In the present study, we purified caldecrin from rat pancreas and determined its primary structure by cDNA cloning. The predicted caldecrin protein is presumed to be synthesized as a preproenzyme of 268 amino acids with a signal peptide of 16 amino acids and an activation peptide of 13 amino acids, and is, with the exception of a central region, almost identical to the reported rat pancreatic elastase IV sequence. The caldecrin gene is selectively expressed in the pancreas, as judged by Northern blot analysis. After expression in BMT-10 cells, immunoreactive caldecrin was found in the culture supernatant, and it inhibited the parathyroid hormone-stimulated 45Ca release from cultured fetal long bones. Catalytic site mutants were synthesized in a baculovirus system, and recombinant mutants also decreased the serum calcium level of mice. These data implicate caldecrin, a protease closely related to elastase IV, in the regulation of blood calcium levels.

Amino Acid Sequence↗

PubMed1995

Protective effect of coenzyme Q10 on cultured skeletal muscle cell injury induced by continuous electric field stimulation.

The protective effect of coenzyme Q10 (CoQ10) on continuous electric field stimulation-induced muscular injury was investigated in cultured cells established from neonatal rat femoral muscles. After cultivation for 9 days, skeletal muscle cells contracted and relaxed rhythmically for 4 hr in response to continuous electric field stimulation (power, 5 V; duration, 5 msec; amplitude, 3 Hz). After the onset of the stimulation, lactate and lactate dehydrogenase (LDH) release and intracellular Ca2+ contents ([Ca2+]i) at relaxation increased gradually. In contrast, the intracellular ATP contents decreased. The addition of 5 microM CoQ10, but not alpha-tocopherol and radical scavengers, to the culture medium protected the cells against these biochemical changes after the stimulation. Verapamil, an inhibitor of Ca2+ channels, also attenuated the increase in [Ca2+]i at relaxation and LDH. These results suggested that one of the causal mechanisms of muscular injury is an increase in [Ca2+]i due to the excess entry of extracellular Ca2+, and that CoQ10 can protect skeletal muscle cells against such undesirable biochemical changes.

Adenosine Triphosphate↗

PubMed1995

A comparison of biological effects of modulated carbon-ions and fast neutrons in human osteosarcoma cells.

PURPOSE: To compare the biological effects of a 135 MeV/u carbon-ion beam and 13 MeV fast neutron beam using human osteosarcoma cells. METHODS AND MATERIALS: We have studied the clonogenic cell survival, recovery of potentially lethal damage (PLD) in plateau phase cells, and spheroid cure in multicellular spheroid after irradiation at various positions in the plateau and spread out Bragg peak (SOBP) of a 135 MeV/u carbon-ion beam and with 13 MeV neutrons. The carbon beam had a 4-cm range in water and a range filter was used to produce a 3-cm extended-peak region. The reference radiation was 137Cs gamma-rays. RESULTS: The relative biological effectiveness (RBE) values for 10% survival level of plateau phase cells for carbon-ions at the position of plateau, proximal peak, midpeak, and distal peak within the SOBP, and neutrons were 1.71, 2.48, 2.63, 3.47, and 2.29, respectively. Corresponding RBE values at 1% level were 1.64, 1.93, 2.06, 2.49, and 2.05. The extent of recovery from PLD was reduced after carbon-ions at proximal peak, midpeak, and distal peak, and neutrons, although not substantially reduced after carbon-ions at plateau. The RBE values for 50% spheroid cure level of spheroids for carbon-ions at the position of plateau, proximal peak, midproximal peak, middistal peak, and distal peak within the SOBP, and neutrons were 1.69, 1.88, 1.87, 1.94, 2.03, and 1.90, respectively. CONCLUSIONS: The biological parameters measured all indicate an approximately comparable biological effectiveness between 75-80 KeV/microns carbon-ions of the SOBP and 13 MeV neutrons in the human tumor model studied in vitro.

Carbon↗

PubMed1995

Antitumor activities of a new indolocarbazole substance, NB-506, and establishment of NB-506-resistant cell lines, SBC-3/NB.

The novel anticancer glucosyl derivative of indolo-carbazole (NB-506), an inhibitor of DNA topoisomerase I, exhibited strong in vitro cytotoxicity against various human cancer cell lines. In order to elucidate its cytotoxic mechanisms, we established nine NB-506-resistant sublines with different resistance ratios from human small cell lung cancer cells (SBC-3/P) by stepwise and brief exposure (24 h) to NB-506. Among them, SBC-3/NB#9 was 454 times more resistant to NB-506 than the parent cell line. The SBC-3/NB#9 cells showed cross-resistance only to topoisomerase I inhibitors, such as 11,7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecia and 7-ethyl-10-hydroxy-camptothecin, and not to other anticancer drugs, such as vincristine, vinblastine, Adriamycin, etoposide, and teniposide. These results indicate that the difference on the effect of topoisomerase I was considered to be related to a resistance mechanism. The topoisomerase I activities of nuclear extracts eluted from SBC-3/NB#9 cells was only one-tenth of the parent cell activity. A Western blotting study indicated that this lower activity was due to a lower amount of DNA topoisomerase I. Furthermore, we found correlations between topoisomerase I activity and sensitivity to NB-506 in sublines with different degrees of resistance. Accumulation of 3H-labeled NB-506 by SBC-3/NB#9 cells was only one-fifth of that by the parent cells, whereas intracellular accumulation of 3H-labeled camptothecin by both cell lines did not differ. The reduction of accumulation was specific to NB-506, and this result may explain why the resistance ratio for NB-506 was higher than those for 11,7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin and 7-ethyl-10-hydroxy-camptothecin.

Antineoplastic Agents↗

PubMed1995

The scid factor on human chromosome 8 restores V(D)J recombination in addition to double-strand break repair.

The murine severe combined immune deficiency mutation (scid) is characterized by a lack of B- and T-lymphoid cells due to a defect in lymphoid V(D)J recombination. Moreover, defective rejoining of DNA double-strand breaks (dsb) in scid cells also results in a marked increase in sensitivity to ionizing radiation. Recently, the putative human homologue of the murine scid gene locus, HYRC1, was assigned to human chromosome 8q11, based on the radiation sensitivity of scid cells as compared to scid:human cell hybrids carrying portions of human chromosome 8. Given the precedent (e.g., ataxia-telangiectasia) for genes other than the affected one being able to complement radiation defects, we were interested in determining if the V(D)J recombination defect was also corrected by the HYRC1 locus. The V(D)J recombination analysis using extrachromosomal DNA substrates in control scid cells (SC3VA2) versus complemented cells (RD13B2) indicates that the radiation sensitivity-complemented cells (RD13B2) are also fully complemented for the V(D)J recombination reaction, whereas the control (uncomplemented) cells (SC3VA2) fail to carry out V(D)J recombination normally. Slightly over 60% of the radiation-induced dsb are rejoined even in scid cells, and this alternative pathway is temperature sensitive. Only the remaining 30-35% of dsb require the introduction of the HYRC1 locus, and this pathway is not temperature sensitive. This merely partial contribution of the scid factor to the repair process suggests the presence of another pathway of dsb repair. Our results indicate that the HYRC1 locus, assigned to human chromosome 8q11, encodes the scid factor, which is involved in all V(D)J recombination coding joint formation and in 30-35% of dsb repair by the temperature-resistant pathway.

Animals↗

PubMed1995

Immunohistochemical evidence that tumors elicit the synthesis of estrogen receptors in the submandibular gland of female rats.

We have demonstrated the presence of estrogen receptor mRNA and the mature protein in the cytoplasm and nucleus, respectively, of a 9,10-dimethyl-1,2-benzathracene-induced submandibular gland tumor in female rats. We have previously shown that progesterone receptors are also present in human salivary gland tumors. These results suggest that endocrine therapy may be effective in treatment of submandibular gland tumors.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Melittin cardiotoxicity in cultured mouse cardiac myocytes and its correlation with calcium overload.

Venom from the honey bee Apis mellifera induces cardiovascular dysfunction. We studied which constituent(s) of the venom induces cardiotoxicity and how, using cultured cardiac myocytes from mouse fetuses. Among the venom constituents, only melittin caused contractile and morphological effects; other peptides, such as apamin and mastparan; enzymes, such as phospholipase A2; and low-molecular-weight compounds, such as histamine and dopamine, did not. Treatment with 4.5 micrograms/ml melittin, which accounts for about half the dry weight of the venom, induced the same cardiotoxic effects as treatment with 9.0 micrograms/ml whole venom; these effects were a transient increase in the spontaneous beating rate, then a decrease, then cessation of beating, and finally, morphological degeneration. The cardiotoxicity of whole bee venom was completely destroyed by pretreatment of the venom with antimelittin antibody. These results suggest that bee venom cardiotoxicity is attributable to melittin. When spontaneous beating ceased following the addition of melittin or whole venom, an increase in systolic [Ca2+]i, was observed. On further incubation with melittin or bee venom, morphological injury, such as balloon degeneration, occurred concomitant with a further increase in the [Ca2+]i. An extracellular Ca2+ concentration of more than 10(-6) M was necessary for morphological injury. Melittin depolarized the maximum diastolic potentials, inhibited the generation of action potentials, and induced an increase in [Na+]i. Cells were protected against the melittin-induced increase in [Ca2+]i by pretreatment with bepridil, an inhibitor of Na(+)-Ca2+ exchange, but not by Ca2+ channel blockers such as verapamil. These observations suggest that the melittin-induced increase in [Ca2+]i was due to entry of extracellular Ca2+ via the sarcolemmal Na(+)-Ca+ exchange system.

Animals↗