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Biomedical subjects

K Kawamura

Publications and source records attributed to K Kawamura.

At least 307 records · Page 17Linked to original sources
PubMed1994

[A case of neurofibromatosis with occlusion of multiple cerebral artery, moyamoya phenomenon and scoliosis].

Cases of cerebrovascular occlusive lesion with neurofibromatosis have rarely been reported. We report here, the case of a 57-year-old woman who twice had sudden onset of brain hemorrhage. She had a family history of neurofibromatosis. Her elder daughter and her niece had a diagnosis of neurofibromatosis and examination showed café au lait spots and neurofibroma over the body, accompanied with scoliosis. CT scans revealed subependymal hemorrhage at the first onset of cerebral bleeding and secondly showed a high-density mass at the left basal ganglia. SPECT(99mTC-HMPAO) showed decreased activity in the left frontal and temporal lobe. Angiogram revealed multiple occlusive lesions of the cerebral arteries, including occlusions of the bilateral anterior cerebral artery and the right middle cerebral artery at the proximal portion and stenosis of the left posterior artery at the proximal portion. Abnormal vascular networks (so called Moyamoya phenomenon) at the base of the brain were also seen bilaterally. Seizinger and others have found a genetic locus of this disease in the use of genetic engineering, and Riccardi showed that mast cell is related to the tumorous growth of neurofibroma and suggested a possibility of medical treatment for growing neurofibroma by stabilizing mast cell function with ketotifen. We anticipate the treatment for this disease will be established in recent years.

Cerebral Angiography↗
PubMed1994

Genetic instability of human cells with DNA related to human retrovirus.

To elucidate the role of HTLV-I in human neoplasia, DNA was extracted from tumor tissues, cultured cells, and/or sera from 20 HTLV-I seropositive and from 10 seronegative cancer patients, subjected to PCR-PAGE, and analyzed by Southern hybridization. HTLV-I related sequences were detected in tumors of the seropositives with different types of cancer. In the seronegatives, gag related sequences were detected in some tumors, whereas LTR related sequences were detected in only uterus carcinoma and tax related sequences in none of tumors examined. These sequences were detected in tumor cells as well as lymphoid cells by in situ hybridization. Some of these sequences were also detected in cultured fibroblasts derived from ATL patients. Cultured normal human lymphocytes grew continuously in conditioned media following HTLV-I infection, and transformed on exposure to carcinogens. Chromosome changes in transformed cells appeared clustering to chromosomes abnormalized on HTLV-I infection. The frequency of abnormal chromosomes in lymphocytes was significantly higher in the seropositives and in their family members than in seronegative normal donors. The frequency increased with advancement of host age in the seropositives but not in the seronegatives. These findings indicate that some individuals carry HTLV-I related sequences that may be derepressed by host aging and resulted in increasing genetic instability of host cells rendering them increasingly susceptible to carcinogens.

Adult↗
PubMed1994

[Features of filamentous cytoskeletons in acquired multidrug-resistance of HL-60 human leukemia cell line].

Acquired resistance to chemotherapeutic drugs by tumor cells is an important obstacle to effective therapy of human malignancy. These resistance cell lines originated from human or rodent have been characterized by increased expression of MDR (Multidrug-resistance) gene and P-glycoprotein which plays as efflux pump of drugs from cells. These multidrug-resistance sublines also have been reported increased activities of protein kinases and glutathione S-transferase-pi. Although there have been extensive biophysical and biochemical characterization of the differences between parental lines and MDR tumor cell sublines, morphologic observations have been limited. In this study, filamentous cytoskeletons which involve many biological phenomena such as maintenance of cell morphology, mitosis, cellular movement, transport, and adhesion, were observed by confocal laser microscopy. To compare the expression of each cytoskeletons, fluorescent intensities of cells stained for each cytoskeletons were measured by confocal laser microscopic system. Utilizing this methodology, higher microtubular expression was observed in HL-60/ADR and K562/ADR than in their parental lines, but no significant differences of actin and vimentin were observed. Phosphorylation by protein kinases has been established as a key factor in the regulation of cytoskeletal function. But little is known about the role of protein phosphorylation in cytoskeletal function. Since increased activities of PKC and PTK were detected in HL-60/ADR, the effect of PKC inhibitor, staurosporine (STR), or PTK inhibitor, genistein (GNS), on cell growth was detected. STR and GNS reduced the resistance to Adriamycin in HL-60/ADR. Furthermore, STR and GNS disrupted the filamentous structure of microtubules in HL-60/ADR, and suppressed the expression of microtubules to 37%, and 49%, respectively. In contrast, PKC activator, phorbol ester (TPA), caused stronger microtubular assembling in HL-60/ADR, and increased the expression of microtubules to 134%. Resulting from this study, it is likely that acquired MDR of HL-60 and K562 was associated with increased expression of microtubules, and microtubular assembling or disassembling was considered to be regulated in part by PKC and PTK.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Transdifferentiation of pigmented multipotent epithelium during morphallactic development of budding tunicates.

In the budding tunicate, Polyandrocarpa misakiensis, the atrial epithelium is the major formative tissue giving rise to the pharynx, digestive tract, brain and endostyle of a bud. We show here that this multipotent epithelium carries several differentiation markers that are lost in the process of bud development. In both adult animals and growing buds, the atrial epithelium contained orange-pigmented granules in the cytoplasm. In developing buds, on the other hand, the cells committed to organ primordia have lost the granules, taken a cuboidal shape and have a large nucleus with a prominent nucleolus, like undifferentiated cells. The atrial epithelium was also characterized by ALP expressed on the apical surface of the cell. During budding the enzyme activity disappeared from the atrial epithelium and reappeared in the primordial digestive tract. Immunohistochemical studies suggested strongly that during gut formation, ALP antigens has been switched from the epithelial isoform to the intestinal isoform. These results have shown that in P. misakiensis budding involves transdifferentiation of multipotent, but differentiated epithelium, confirming our previous results (Fujiwara and Kawamura, Dev. Growth Differ. 34:463-472, 1992).

Alkaline Phosphatase↗
PubMed1994

[Studies on the modified dimethylmethylene-blue (DMB) method for determining glycosaminoglycans (GAG) in urine].

The measurement of glycosaminoglycans (GAG) in urine is very important because GAG is an essential constituent of urinary diseases. Since previously reported methods of determination of GAG are quite complicated, dangerous or not stable, we developed a very simple and rapid method to estimate the content of GAG in urine using a microplate and microplate reader. An aliquot of diluted urine is mixed with a 1,9, dimethylmethylene blue (DMB) dye. The assay is based on the metachromatic shift in absorption maximum which occurs when sulfated glycosaminoglycans are added to the dye. The recovery of GAG is good. Other urinary compounds such as sugar, protein and blood did not influence the measurement of GAG. A good correlation was obtained between the modified DMB method and Blumenkrantz and Asboe-Hansen's method (r = 0.737, p < 0.001). The accuracy of this method makes it useful for screening urinary diseases.

Adult↗
PubMed1994

[Evaluation for serum apolipoproteins in patients with diabetes mellitus].

Six fractions of serum apolipoproteins (apolipoprotein A-I, A-II, B, C-II, C-III and E) obtained from 100 patients with diabetes mellitus not administered any antihyperlipidemic drugs were measured to clarify the relationship between diabetes mellitus and the abnormal lipidosis. The serum concentrations of apolipoprotein B, C-II and C-III were significantly higher in these diabetics than in the controls (p < 0.05), and that of apolipoprotein E was significantly lower (p < 0.01). The serum concentrations of apolipoprotein C-II, C-III and E (p < 0.05) as well as HbA1C and FRA (p < 0.001) were significantly higher in the insufficient control group (FPG > or = 140 mg/dl) of diabetes mellitus. The serum concentrations of apolipoprotein C-II, C-III and E were significantly higher in the treated groups (p < 0.05). The serum concentrations of apolipoprotein B, C-II, C-III and E were significantly higher (p < 0.01) in the high cholesterol group (> 220mg/dl) and the high triglyceride group (> 150mg/dl) among the diabetic groups, but no significant differences were observed in the concentrations of apolipoprotein A-I and A-II.

Adult↗
PubMed1994

Suppression of retroviral tumors in hosts immune to viral oncogene product.

Feline sarcoma virus of Snyder-Theilen strain (ST-FeSV) induces sarcomas in Wistar/Ma rats following neonatal virus injection. Induced tumors express the viral oncogene product (P85) and elicit in hosts the specific serum anti-P85 antibody detectable by Western blot analysis. Syngeneic adult female rats were immunized with an ST-FeSV induced sarcoma that was 100% transplantable to syngeneic adult rats. Newborns from immunized rats (vaccinated rats) were found to carry anti-P85 in their sera at birth. Following neonatal injection of the virus to vaccinated and non-vaccinated control rats, tumor incidence was found to be lower and survival time significantly longer in vaccinated rats than in controls (p < 0.01). A nonapeptide known to be thymic hormone (FTS) showed suppressive effects on tumor development. These results indicate that tumors caused by perinatal retrovirus infection may be suppressed by efficient elicitation of cell-mediated immune response against the product of oncogene of the causative virus.

Amino Acid Sequence↗
PubMed1993

Human heart-type cytoplasmic fatty acid-binding protein in serum and urine during hyperacute myocardial infarction.

We have previously reported that serum and/or urinary human heart-type cytoplasmic fatty acid-binding protein (HH-FABPc) can be used as an early indicator of myocardial injury (Clin Biochem 1991; 24: 195-201). To confirm the usefulness of HH-FABPc as an early diagnostic indicator of acute myocardial infarction (AMI), its serum and urinary levels were measured in samples obtained within 6 h after the onset of acute coronary syndrome related symptoms. Samples were collected from 97 patients, who were composed of 63 with AMI, 24 with unstable angina and 10 with chest pain syndrome. The positivity of serum and urinary HH-FABPc and cardiac creatine kinase isozyme MB (CK-MB) was analyzed in these samples. Serum HH-FABPc levels in AMI were above normal in 91.4% (64/70) of the samples tested within 3 h of the onset of symptoms and in 100% (111/111) of those tested at 3-6 h. Elevated urinary HH-FABPc levels in AMI were obtained in 88.9% (8/9) of samples at 0-3 h and in 75% (6/8) at 3-6 h. CK-MB activity in AMI was positive in 20% (8/40) and 66.3% (53/80) of serum samples at 0-3 h and 3-6 h, respectively. HH-FABPc was always positive when a serum sample was positive for CK-MB. Serum HH-FABPc at 0-6 h in chest pain syndrome and in unstable angina were positive in 17.8% (5/28) and 56.7% (34/60), respectively. The elevated HH-FABPc in serum and urine was noted much earlier than that of CK-MB during the hyperacute phase of AMI. HH-FABPc showed high positive value in unstable angina, but it was low in normal coronary patients having chest pain. However, HH-FABPc level in unstable angina and chest pain syndrome was lower than that of AMI. Thus, HH-FABPc may be a valuable indicator for the diagnosis of hyperacute myocardial infarction.

Adult↗
PubMed1993

Oxidative damage of nuclear DNA in liver of rats exposed to psychological stress.

Male Sprague-Dawley rats were exposed to conditioned emotional stimuli in a communication box, which is much more psychologically conditioned stress than the commonly used restraint and water immersion, to investigate the induction of oxidative DNA damage by psychological stress. Significantly higher levels of 8-hydroxy-2'-deoxyguanosine in rat liver nuclear DNA than in the controls [1.46 +/- 0.19 (SD) 8-hydroxy-2'-deoxyguanosine/10(5) deoxyguanosine] were detected immediately after the second (1.90 +/- 0.27, P < 0.01), third (3.10 +/- 0.94, P < 0.01), and fourth exposure (2.95 +/- 1.17, P < 0.01) to conditioned emotional stimuli. This is the first evidence that oxidative damage to nuclear DNA is induced by psychological stress.

Animals↗
PubMed1993

Expression of three nonallelic genes coding calmodulin exhibits similar localization on the central nervous system of adult rats.

By Northern blot analysis with the digoxigenin-labeled antisense RNA probes of the noncoding regions, the transcripts of three calmodulin (CaM) genes, CaMI, CaMII, and CaMIII, were separately detected in 12 different tissues of adult Wistar albino rats, without any cross-hybridization. The mRNAs of all three CaM genes were abundant in the central nervous system (CNS) as well as in the testis, although ubiquitous expression was detected at low levels in the other tissues. There were subtle but significant differences in the tissue-specific distribution of the three CaM gene RNAs. By in situ hybridization, strong hybridization of the three CaM gene probes was observed in common in large projection neurons of the CNS: the hippocampal pyramidal cells, the cerebellar Purkinje cells, and the large neurons of the cerebral neocortex, the pyriform cortex, the mesencephalon, the pons, and the spinal cord. The expression of the three CaM genes was at lower levels in small interneurons of the CNS. These profiles of expression were almost the same among the three CaM genes. Thus, all three CaM genes were coordinately expressed in neurons of the adult rat CNS. Certain regulatory mechanisms of the three CaM genes seemed to mediate similar tissue- and cell type-specific expression in the CNS.

Animals↗
PubMed1993

Development of the ectopically transplanted primordium of epithelial hypophysis (anterior neural ridge) in Bufo japonicus embryos.

It has recently been demonstrated that the epithelial pituitary of the toad is not stomodeal, but placodal, in origin. The placodal cells in the anterior part of the neural ridge (ANR) of the open neurulae are the exclusive source of the epithelial pituitary gland. The present study was undertaken to see the self-differentiating ability of these cells in an ectopic environment. Bufo japonicus embryos at the tailbud stage received implants of either the ANR from open-neurula-stage embryos, or the pituitary primordium from tailbud-stage embryos (the ANR derivative beneath the forebrain floor) into the tail. Development of the pars intermedia and the pars distalis was monitored immunohistochemically using antisera against both synthetic alpha melanophore-stimulating hormone (alpha MSH) and bullfrog prolactin (PRL). Neither the immunoreactive alpha MSH cells nor the immunoreactive PRL cells differentiated from the neural ridge when it was dislocated from the original site at the open neurula stage. On the other hand, in grafts of the pituitary primordium transplanted from the tailbud-stage embryos, immunoreactive PRL cells developed invariably and immunoreactive alpha MSH cells were detected at an incidence of 72%. The significance of the role of brain tissue surrounding the pituitary anlage in differentiation of the pars intermedia and pars distalis is discussed.

Animals↗
PubMed1993

Immunocytochemical localization of atrial natriuretic factor (ANF)-like peptides in the brain and heart of the treefrog Hyla japonica: effect of weightlessness on the distribution of immunoreactive neurons and cardiocytes.

The localization of atrial-natriuretic factor (ANF)-like immunoreactivity was investigated in the brain and heart of the treefrog Hyla japonica by the indirect immunofluorescence technique. Concurrently, the effect of weightlessness on the distribution of ANF-containing neurons and cardiocytes was studied in frogs that were sent into space for 9 days on the space station "MIR." In control animals, the amygdala contained the most prominent group of ANF-immunoreactive cells and fibers. ANF-positive neurons and nerve processes were also detected in other areas of the telencephalon such as the nucleus olfactorius, the pallium mediale, and the striatum. In "space frogs," the intensity of labeling of the amygdala and nucleus olfactorius was similar to that seen in control animals. In contrast, the pallium and the striatum of "space frogs" were totally devoid of positive cell bodies. In the diencephalon, of all animals, numerous ANF-immunoreactive perikarya and fibers were seen in the hypothalamus, the anterior thalamus, the infundibulum, and the median eminence. ANF-positive cell bodies were also noted in the lateral forebrain bundle of control frogs but were absent in "space frogs." The major difference between control and "space frogs" was observed in the posterior nuclei of the thalamus. In "space frogs," the nucleus posterocentralis thalami and the nucleus posterolateralis thalami exhibited large ANF-immunoreactive perikarya, while, in control frogs, these nuclei only contained scarce positive nerve fibers. In the mesencephalon, ANF-positive cell bodies and nerve processes were seen in the nucleus tegmenti mesencephali, the interpeduncular nucleus, and the nucleus cerebelli of all animals. However, stained perikarya were only observed in the nucleus reticularis isthmi of control frogs. In the heart, atrial cardiocytes exhibited intense ANF-like immunoreactivity. ANF-positive myocytes were also detected in the subpericardial region of the ventricle. The density and distribution of the staining were identical in the heart of control and "space frogs." These data support the concept that prolonged exposure to microgravity affects biosynthesis and/or release of ANF-related peptides in discrete regions of the amphibian brain.

Animals↗
PubMed1993

Lisinopril reduces cardiac hypertrophy and mortality in rats with aortocaval fistula.

We evaluated the effects of lisinopril (1 mg/kg per day) on hemodynamics, cardiac hypertrophy, and neurohumoral factors in Wistar rats with an abdominal aortocaval fistula. After 4 weeks of treatment, the results were compared with values obtained for untreated rats with a fistula and for sham-operated rats. Volume loading induced biventricular hypertrophy, hemodynamic signs of high-output heart failure (increased cardiac output, left ventricular end-diastolic pressure, and pulse pressure), and impaired renal function (decreased renal blood flow and kidney weight; increased blood urea nitrogen). Lisinopril did not affect these cardiorenal hemodynamics, but decreased left ventricular mass and mortality rate (both P < 0.05). Lisinopril attenuated the increase in plasma norepinephrine, and increased plasma renin activity (both P < 0.05). Thus, lisinopril reduced left ventricular mass and mortality in rats with high-output heart failure without changing the cardiorenal hemodynamics. Neurohumoral inhibition may play a role in the beneficial effects of lisinopril.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

Purification of a fibroblast-inhibitory factor from Actinobacillus actinomycetemcomitans Y4.

A factor showing inhibitory activity against human gingival fibroblasts was extracted from the cytosol fraction of Actinobacillus actinomycetemocimitans Y4. The activity markedly inhibited the proliferation of human gingival fibroblasts, but had no effect on cell viability or gross morphology. No such activity was found in cytosol fractions from either Porphyromonas gingivalis 381 or Escherichia coli HB101. The extract from A. actinomycetemocomitans Y4 was then purified by anion-exchange chromatography, hydroxyapatite chromatography and gel-filtration chromatography to give a single band on SDS-PAGE with an apparent molecular mass of 65 kDa. The purification ratio was 183-fold with a recovery rate of 5% compared with the crude extract (starting material) when the activity was assessed by direct cell counts.

Actinobacillus↗
PubMed1993

Preparation of needle-like hydroxyapatite by homogeneous precipitation under hydrothermal conditions.

Preparation of hydroxyapatite was carried out by a homogeneous precipitation technique using hydrothermal reactions of Ca(EDTA)2- and PO4(3-) at 130-250 degrees C and pH 4-10. Hydroxyapatite and monetite were formed above pH 6 and below pH 4, respectively. Needle-like hydroxyapatite was formed at high temperatures above 130 degrees C. The length of the needle-like hydroxyapatite crystal increased with increasing working solution pH and temperature.

Calcium↗