Biomedical subjects

H Kitano

Publications and source records attributed to H Kitano.

At least 91 records · Page 5Linked to original sources

PubMed1998

The perfect C. elegans project: an initial report.

The soil nematode Caenorhabditis Elegans (C. elegans) is the most investigated of all multicellular organisms. Since the proposal to use it as a model organism, a series of research projects have been undertaken, investigating various aspects of this organism. As a result, the complete cell lineage, neural circuitry, and various genes and their functions have been identified. The complete C. elegans DNA sequencing and gene expression mapping for each cell at different times during embryogenesis will be identified in a few years. Given the abundance of collected data, we believe that the time is ripe to introduce synthetic models of C. elegans to further enhance our understanding of the underlying principles of its development and behavior. For this reason, we have started the Perfect C. elegans Project, which aims to produce ultimately a complete synthetic model of C. elegans' cellular structure and function. This article describes the goal, the approach, and the initial results of the project.

Animals↗

PubMed1998

Immunohistochemical detection of vasoactive intestinal polypeptide (VIP) and the VIP receptor in the rat inner ear.

Vasoactive intestinal polypeptide (VIP) is a 28 amino acid peptide that was originally isolated from porcine duodenum. The presence of VIP has been demonstrated in the central nervous system and peripheral tissues. However, there have been few reports on VIP as a neurotransmitter, especially in the inner ear. To investigate the function of VIP in the rat inner ear, we examined the expression of VIP and the VIP receptor by immunohistochemistry. Using the anti-VIP and VIP receptor antibodies, scattered fibres in the cochlear nerve trunk demonstrating VIP-like immunoreactivity were found, and the spiral ganglion cells demonstrated ring-shaped VIP-like immunoreactivity. Immunoreactivity for the VIP receptor was predominantly found in the spiral ganglion cells. Our results suggest that VIP may play an important role as a possible neurotransmitter not only in the local control of cochlear blood flow, but also in the auditory system.

Animals↗

PubMed1998

Surgical observations on the endolymphatic sac in Meniere's disease.

OBJECTIVE: This study aimed to clarify the pathoanatomic characteristics of the endolymphatic sac in Meniere's disease by surgical observations. STUDY DESIGN: The study design was a retrospective case study conducted in the setting of University Hospital at Shiga University of Medical Science. PATIENTS: Studied were 101 patients with Meniere's disease who underwent endolymphatic sac drainage surgery at the university hospital by the same surgical team between 1984 and 1995. Control group consisted of 23 patients with non-Meniere's disease. MAIN OUTCOME MEASURES: Photographs were taken of the sac in 101 patients with Meniere's disease during endolymphatic sac drainage surgery, and the pathoanatomic findings of the sacs were classified into three grades regarding position (types I, II, III), size (large, intermediate, small), color (red, intermediate, white), and vascularity (fair, intermediate, poor). Statistical difference was studied between Meniere's group and non-Meniere's group by chi-square test. RESULTS: The patients with Meniere's disease were found to have endolymphatic sacs located inferiorly to the posterior semicircular canal, very close to the jugular bulb (type III) (p < 0.001). The sacs also were smaller in size (p = 0.068), whiter in surface color (p = 0.0036, 0.01), and of less vascularity (p = 0.051) than those of the patients with non-Meniere's disease. The comparisons showed significant differences only in position and color. CONCLUSION: The patients with Meniere's disease were found to have endolymphatic sacs located inferiorly to the posterior semicircular canal, very close to the jugular bulb. The sacs also were whiter in surface color.

Endolymphatic Sac↗

PubMed1998

First-pass radionuclide angiography using iodine-123 myocardial tracers and a multicrystal gamma camera.

UNLABELLED: The purpose of this study was to validate the accuracy of the assessment of ventricular function by first-pass radionuclide angiography (FPRNA) with 123I myocardial tracers and a multicrystal gamma camera. METHODS: Left ventricular ejection fraction (LVEF) and right ventricular ejection fraction were measured in 69 patients by FPRNA using 123I myocardial tracers (126 +/- 7 MBq) and 99mTc tracers (541 +/- 141 MBq) on a multicrystal gamma camera with a high-sensitivity collimator. For 44 patients, ejection fraction values measured by 123I-FPRNA were compared to those estimated by equilibrium radionuclide angiography (ERNA). Visual wall-motion analysis was also performed to judge clinical acceptability of 123I-FPRNA images for identification of wall-motion abnormality. RESULTS: Mean LVEFs (%) estimated by 123I-FPRNA and by 99mTc-FPRNA were 49.6 +/- 13.6 and 49.1 +/- 14.1, respectively (nonsignificant p value). An excellent correlation was found between LVEFs estimated by 123I-FPRNA and 99mTc-FPRNA (r = 0.96, s.e.e. = 1.9%). Values of LVEF measured by 123I-FPRNA also demonstrated excellent correlation with those measured by ERNA (r = 0.95, s.e.e. = 2.2%). A good correlation was also noted between right ventricular ejection fractions measured by 123I-FPRNA and 99mTc-FPRNA (r = 0.72, s.e.e. = 4.0%). The Spearman rank correlation coefficient between 123I-FPRNA and ERNA wall-motion scores was 0.87 (n = 135, p < 0.001). CONCLUSION: Resting ventricular function can be reliably measured with 123I-FPRNA in combination with a multicrystal gamma camera. This indicates that the assessment of ventricular function is feasible in conjunction with 123I myocardial imaging without an increase in cost or radiation dose to patients.

Adult↗

PubMed1998

[A case of osteolytic metastases from breast cancer effectively treated with pamidronate].

A 55-year-old woman complained of neck pain ten years after the mastectomy. She was diagnosed as multiple bone metastases and received chemoendocrine therapy with 5'-DFUR and tamoxifen. Bone scintigram showed progressive disease, so we attempted biweekly administration of fadrozole and pamidronate (30 mg). After four months, pamidronate administration relieved her neck pain. CT revealed that all lytic lesions of cervical and thoracic vertebra showed sclerosis 11 months after pamidronate infusion. New lytic lesions are not defined, and the sclerosis has continued thus far. Pamidronate therapy is promising as an effective treatment in patients with osteolytic metastasis from breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1998

Abnormality of myocardial oxidative metabolism in noninsulin-dependent diabetes mellitus.

UNLABELLED: The purpose of this study was to evaluate oxidative metabolism and its response by dobutamine in patients with noninsulin-dependent diabetes mellitus (NIDDM) using 11C-acetate PET. METHODS: We studied 16 patients with NIDDM (9 men, 7 women; mean age 53.7 +/- 12.8 yr) and 6 healthy male control subjects (mean age 41.8 +/- 17.2 yr). None of them had an abnormality on stress-perfusion SPECT. The 11C-acetate clearances (Kmono) were compared regionally for five myocardial segments in all subjects at rest and during low-dose dobutamine stress in 13 patients (8 patients with NIDDM, age 51.9 +/- 13.6 yr; 5 healthy male control subjects, age 45.6 +/- 16.3 yr). Correlation between regional Kmono and rate-pressure product (RPP) was also studied. RESULTS: At rest, the clearance of 11C-acetate was slightly heterogeneous for both patients with NIDDM and healthy control subjects, with smaller values in the apex and inferior wall in both groups. The difference became significant during dobutamine stress in the patients. The RPP-to-Kmono (average for five segments) ratio at rest was slightly smaller in the patients (1042.7 +/- 559.1 x 0.01) than in the healthy control subjects (1391.4 +/- 209.6 x 0.01, not significant), and those during dobutamine stress were almost the same in the two groups (1457.3 +/- 737.4 x 0.01 and 1486.0 +/- 211.8 x 0.01, respectively). A significant correlation was seen between regional Kmono and RPP in every segment in the healthy control subjects (average; r = 0.89; p < 0.01), whereas more scattered correlation with greater regional variation was observed in the patients (average; r = 0.31; p value was not significant). CONCLUSION: Patients with NIDDM showed slight regional heterogeneity in myocardial oxidative metabolism. They also had more scattered correlation between myocardial oxidative metabolism and cardiac work (RPP) than healthy control subjects, with the smallest correlation coefficient observed in the inferior wall. These findings may help the understanding of dynamics in myocardial oxidative metabolism of NIDDM hearts.

Acetates↗

PubMed1997

Vasopressin and oxytocin receptor mRNAs are expressed in the rat inner ear.

The cause of endolymphatic hydrops, a characteristic finding in Menière's disease, is not known. To study the possible involvement of the neurohormones vasopressin and oxytocin in this condition, we investigated whether transcripts of the genes encoding the arginine vasopressin (AVP) and oxytocin receptors are expressed in the rat inner ear. Utilizing the reverse transcription-polymerase chain reaction (RT-PCR) method, primers specific for each receptor showed a single message band of the expected size in the rat inner ear. When the PCR products were cloned, the sequences were identical to those of the real-type (V2) AVP receptor and oxytocin receptor transcripts. The finding of vasopressin and oxytocin receptor mRNAs in the inner ear suggests that these neurohypophyseal hormones may have roles in the regulation of inner ear fluid. In particular, the presence of vasopressin receptor mRNA in the inner ear supports the hypothesis of a relationship between high plasma vasopressin levels and endolymphatic hydrops.

Animals↗

PubMed1997

Detection of C-type natriuretic peptide (CNP) and atrial natriuretic peptide (ANP-B) receptor mRNAs in rat inner ear.

C-Type natriuretic peptide (CNP) is the third member of the natriuretic peptide family which plays an important role in body fluid homeostasis. To determine a possible role of CNP in regulation of an inner ear fluid, we investigated the expression of CNP and atrial natriuretic peptide B receptor (ANP-B receptor) mRNAs in rat inner ear using a reverse transcription polymerase chain reaction (RT-PCR) method. Amplification products with sizes expected for CNP and ANP-B were detected in the inner ear. After cloning and analysis, the sequences for PCR products were identical to those of CNP or ANP-B receptor in the brain. These results indicate that both CNP and ANP-B receptor are expressed in the inner ear of the rat and suggest that CNP may play a role in inner ear function (such as regulation of inner ear fluid) in an autocrine and/or paracrine manner.

Animals↗

PubMed1997

[Differences in temporal bone development in various ear diseases].

To investigate the differences in temporal bone development in various ear diseases--bilateral Meniere's disease (n = 13), unilateral Meniere's disease (n = 41), unilateral chronic otitis media (COM) (n = 25), temporal bone fracture (n = 9) and otosclerosis (n = 12)--the following 4 distances on a temporal bone CT slice encompassing the lateral semicircular canal (LSC) were measured by using the NIH Image program. These distances included the minimal distance between the posterior semicircular canal (PSC) and the posterior petrous surface (PPS) (P-P distance), the minimal distance between the PSC and the LSC (P-L distance), the minimal distance between the vestibule and the PPS (V-P distance) and the minimal distance between the PSC and the anterior margin of the sigmoid sinus (P-S distance). Both the P-P and V-P distances showed significant differences among the ear diseases, but the P-L and P-S distance did not. Meniere's disease showed significantly shorter P-P and V-P distance especially in bilateral Meniere's disease than those in COM and otosclerosis (p < 0.05). Affected ears in unilateral Meniere's disease showed a shorter P-P distance than non-affected ears (p < 0.01). In contrast, both ears with otosclerosis showed significantly longer P-P and V-P distances than those in Meniere's disease, COM (p < 0.01) and temporal bone fracture (p < 0.05). COM and temporal bone fracture showed intermediate P-P and V-P distances, without a difference between the affected and non-affected ears. In conclusion, the development of the posterior part of the temporal bone is reduced in Meniere's disease and greatly increased in otosclerosis. These findings by CT may be useful for diagnosing ear diseases.

Ear Diseases↗

PubMed1996

Evidence for the involvement of ecto-5'-nucleotidase (CD73) in drug resistance.

Increased ecto-5'-nucleotidase (ecto-5'NT) protein expression in several multidrug-resistant (MDR) cell lines, documented previously by our group, suggests that this enzyme is involved in drug resistance. Here, Northern blot analysis of selected cell lines and their MDR variants positively correlated ecto-5'NT protein with its mRNA expression. An inhibitor of ecto-5'NT enzymatic activity, alpha,beta-methyleneadenosine 5'-diphosphate (AMP-CP), was used to determine if functionally active enzyme had a role in drug resistance. AMP-CP (0.3 mM) reversed the resistance of ecto-5'NT-positive MDR cells (MCF7/A6, L1210/A) to doxorubicin, whereas it did not affect the doxorubicin sensitivity of the ecto-5'NT-negative parental cell lines or that of 2 ecto-5'NT-negative MDR cell lines (HL60/VCR and A2780/DX5). Furthermore, AMP-CP increased rhodamine uptake and inhibited rhodamine efflux from ecto-5'NT-positive MDR cells without affecting ecto-5'NT-negative MDR cells. The presence of exogenous adenosine (0.5 microM) circumvented AMP-CP-induced inhibition of rhodamine efflux from EL4/ADM cells. AMP-CP inhibited the growth of the ecto-5'NT-positive L1210/A MDR cells but had no effect on the growth of the parental cell line. Determination of intracellular ATP levels indicated that MDR cells which had increased ecto-5'NT expression also had a lower intracellular ATP level than their parental cells. Our results suggest that, in certain MDR cell lines, ecto-5'NT serves as a required accessory molecule in resistance mediated by ATP-dependent mechanisms and that growth-sustaining nucleosides are provided by this salvage pathway.

5'-Nucleotidase↗

PubMed1996

A rice homeobox gene, OSH1, is expressed before organ differentiation in a specific region during early embryogenesis.

Homeobox genes encode a large family of homeodomain proteins that play a key role in the pattern formation of animal embryos. By analogy, homeobox genes in plants are thought to mediate important processes in their embryogenesis, but there is very little evidence to support this notion. Here we described the temporal and spatial expression patterns of a rice homeobox gene, OSH1, during rice embryogenesis. In situ hybridization analysis revealed that in the wild-type embryo, OSH1 was first expressed at the globular stage, much earlier than organogenesis started, in a ventral region where shoot apical meristem and epiblast would later develop. This localized expression of OSH1 indicates that the cellular differentiation has already occurred at this stage. At later stages after organogenesis had initiated, OSH1 expression was observed in shoot apical meristem [except in the L1 (tunica) layer], epiblast, radicle, and their intervening tissues in descending strength of expression level with embryonic maturation. We also performed in situ hybridization analysis with a rice organless embryo mutant, orl1, that develops no embryonic organs. In the orl1 embryo, the expression pattern of OSH1 was the same as that in the wild-type embryo in spite of the lack of embryonic organs. This shows that OSH1 is not directly associated with organ differentiation, but may be related to a regulatory process before or independent of the organ determination. The results described here strongly suggest that, like animal homeobox genes, OSH1 plays an important role in regionalization of cell identity during early embryogenesis.

Cell Differentiation↗

PubMed1996

Ruptured inferior mesenteric artery aneurysm due to segmental mediolytic arteritis.

Segmental mediolytic arteritis is a rare non-inflammatory arteriopathy. Only eight cases have been reported so far. The authors report a case of a ruptured inferior mesenteric artery aneurysm due to segmental mediolytic arteritis in which preoperative angiography revealed lesions and successful surgical treatment was performed. A review of the clinical features of segmental mediolytic arteritis is also presented.

Aneurysm, Ruptured↗

PubMed1996

Role of albumin and high-density lipoprotein as endotoxin-binding proteins in rats with acute and chronic alcohol loading.

In the present study, the role of albumin and high-density lipoprotein (HDL) as endotoxin (Et)-binding proteins in chronically alcohol-fed rats was studied. In acute ethanol-loaded rats, the Et clearance in the blood was slightly prolonged, and the amount of albumin and HDL- bound Et in the blood was markedly increased. In chronic ethanol-loaded rats, the Et clearance was significantly faster than that in the control, and HDL-bound Et was increased. In the chronic ethanol-fed rats with an additional 5 g/kg body weight of ethanol load, the Et clearance was much prolonged, and blood tumor necrosis factor and ALT was elevated, when HDL-bound Et was not further increased. Et-binding capacity of total proteins, albumin, and HDL in the hepatocyte culture medium were increased when the Kupffer cells were preincubated in the medium containing ethanol, and the resultant culture supernatant was added to the hepatocyte culture system. In the culture experiment in the chronic ethanol-loaded rats, such increases were not observed. These results suggest that the increase in Et-binding capacity of HDL and albumin may serve as a protective mechanism against Et in chronic ethanol-loaded rats. An addition of high-dose ethanol to these rats may lead to impaired Et binding and inactivation, which may finally result in increased endotoxicity.

Alcoholic Intoxication↗

PubMed1996

How is embryo size genetically regulated in rice?

It is unclear how embryo size is genetically regulated in plants. Since cereals have a large persisting endosperm, it is expected that embryo size is affected by endosperm development. Nine single recessive mutations, four reduced embryo mutations representing three loci, REDUCED EMBRYO1, REDUCED EMBRYO2 and REDUCED EMBRYO3, four giant embryo mutations derived from a single locus GIANT EMBRYO, and one endospermless mutation endospermless1-2 were analyzed. Every reduced embryo mutation caused reduction of all the embryonic organs including apical meristems and the enlargement of the endosperm. The giant embryo mutants have a reduced endosperm and an enlarged scutellum. However, shoot and radicle sizes were not affected. All the reduced embryo and giant embryo mutations did not largely affect postembryonic development. Accordingly, the expression of genes analyzed are seed-specific. In reduced embryo and giant embryo mutations, abnormalities were detected in both embryo and endosperm as early as 2 days after pollination. endospermless1-1 resulted in an early loss of endosperm, yielding a giant embryo, suggesting that embryo growth was physically limited by the endosperm. A double mutant between giant embryo-2 and club-shaped embryo1-1, which has a normal endosperm and a minute undifferentiated embryo, resulted in a club-shaped embryo1-1 embryo and a reduced endosperm of giant embryo-2, indicating that GIANT EMBRYO regulates the endosperm development. Double mutants between giant embryo-2 and three reduced embryo mutants exhibited the reduced embryo phenotype in both embryo and endosperm, suggesting that reduced embryo mutations cause the enlarged endosperm. Further, a double mutant of reduced embryo3 and endospermless1-1 showed the enlarged embryo in endospermless seed. This confirms that reduced embryo3 does not regulate embryo size but enlarges endosperm size. Together with the results of the other double mutant analysis, REDUCED EMBRYO1, REDUCED EMBRYO2, REDUCED EMBRYO3 and GIANT EMBRYO are concluded to regulate endosperm development.

Genes, Plant↗

PubMed1996

[Long-term results of Feldmann's osteoplastic approach for chronic middle ear disease].

Between 1978 and 1981, Feldmann's osteopathic approach was often used to manage chronic middle ear disease. In this procedure, the superior and posterior segment of the ear canal wall was cut after complete mastoidectomy, removed temporarily and re-positioned in the previous position after handling the diseased focus in the tympanic isthmus area. Forty-one cases (24 cases of non-cholesteatomatous chronic otitis media and 17 cases of cholesteatoma) were followed and long-term results of this procedure were studied with regard to re-operative findings following this procedure. Among the 41 patients, 13 (31.7%) required revision surgery because of cholesteatoma formation, infection etc. Seven of these 13 patients (53.8%) required revision surgery because of cholesteatoma formation after this procedure. None of these 7 cases appeared to involve residual cholesteatoma. The most important problem is that 3 of the 7 patients showing cholesteatoma formation had non-cholesteatomatous chronic otitis media before this procedure. In other words, the Feldmann's osteoplastic approach may iatrogenically induce cholesteatoma formation in non-cholesteatomatous chronic otitis media. The re-operative findings indicated that the re-positioned canal wall in this procedure may have small bony defects or bony erosion, inducing pocket formation through these defects to create a new cholesteatoma. Although recent literature concerning tympanoplasty recommends posterior canal wall reconstruction using cartilage, bone, ceramic material or bone-pate rather than the canal wall down method, careful follow-up should be continued with regard to pocket formation and/or cholesteatoma formation.

Cholesteatoma, Middle Ear↗

PubMed1996

Type II collagen-induced autoimmune ear disease in mice: a preliminary report on an epitope of the type II collagen molecule that induced inner ear lesions.

To identify the epitope on the type II collagen molecule that induced autoimmune ear disease, electrophysiological and histological studies were carried out in DBA/1J mice immunized with native chick type II collagen (Clln) and cyanogen bromide (CNBr) peptide 1I (CB-I1 peptide) that was cleaved from chicken type II collagen with CNBr digestion. Four months after immunization, three of six Clln-immunized mice and five of six CB-I1 peptide-immunized mice developed moderate hearing loss. No control animals showed hearing loss. The pattern of hearing loss was characteristic of progressive deafness. Furthermore, the immunized mice showed temporal lesions involving atrophy of the Corti organ and degeneration of the spiral ganglion, in proportion to the level of the hearing loss. Because similar inner ear lesions were induced by immunization with Clln and CB-I1 peptide, CB-I1 peptide contains at least one epitope that induces autoimmune inner ear disease in collagen II-induced disease on the chick type II collagen molecule involved in pathogenesis of autoimmune ear disease. CB-I1 peptides were concluded to contain the epitope that induces autoimmune inner ear disease in collagen IIn-induced disease.

Animals↗

PubMed1996

Extraction and retention of technetium-99m-ECD in human brain: dynamic SPECT and oxygen-15-water PET studies.

UNLABELLED: The kinetic behavior of 99mTc-ethyl cysteinate dimer (99mTc-ECD) in the human brain was investigated in six normal volunteers. METHODS: Dynamic SPECT and a three-compartmental model were used to estimate the rate constants of 99mTc-ECD in normal human brain. Extraction fraction (E), retention fraction (R) and permeability surface area product (PS product) of 99mTc-ECD were calculated using the rate constants. Regional cerebral blood flow (rCBF) was measured by PET with 15O-water. RESULTS: The rate constants in the cerebral cortex were estimated as 0.307 +/- 0.021 for K1 (influx constant), 0.201 +/- 0.047 for k2 (backdiffusion rate constant), 0.547 +/- 0.103 for k3 (lipophilic-to-hydrophilic conversion constant) and 0.0028 +/- 0.0012 for k5 (rate constant from lipophilic compartment to blood) at rCBF of 0.509 +/- 0.055 ml/g/min (mean +/- s.d.). The first-pass extraction, retention fraction and PS product were calculated as 0.608 +/- 0.069, 0.734 +/- 0.047 and 0.477 +/- 0.060, respectively. The first-pass extraction of 99mTc-ECD decreased significantly with increases in rCBF. The retention fraction and PS product of 99mTc-ECD did not show significant changes within the normal range of rCBF. The net extraction of 99mTc-ECD calculated from the static SPECT image obtained from 20 to 40 min was 0.358 +/- 0.039 in the cortex. CONCLUSION: Technetium-99m-ECD has a fairly high brain extraction, and its retention fraction and PS product appear to be independent of rCBF in the healthy human brain.

Adult↗

PubMed1996

Protective mechanism of high-density lipoprotein against endotoxemia in chronic alcohol ingestion.

In the present study, we evaluated the role of high-density lipoprotein (HDL) as an endotoxin-binding protein in chronically alcohol-fed rats. Although the blood endotoxin level was significantly elevated in chronic ethanol-loaded rats, compared with control rats, serum tumor necrosis factor (TNF), ALT, and lactate dehydrogenase were not elevated. Serum HDL and its endotoxin-binding capacity were significantly increased in chronic ethanol-loaded rats. When Kupffer cells isolated from control and chronic ethanol-loaded rats were cultured in the medium containing 3 to 30 mg/dl HDL and endotoxin (500 ng/ml), endotoxin uptake and TNF production of Kupffer cells were decreased in proportion to the concentration of HDL in the medium. These results suggest that the increase in endotoxin-binding capacity of HDL may serve as a protective mechanism against endotoxin in chronic ethanol-loaded rats.

Alcoholism↗