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Biomedical subjects

M Kaneko

Publications and source records attributed to M Kaneko.

At least 253 records · Page 14Linked to original sources
PubMed1998

Technique for arterial-phase contrast-enhanced three-dimensional MR angiography of the carotid and vertebral arteries.

Our goal was to evaluate whether contrast-enhanced three-dimensional MR angiography using the MR Smartprep technique would enable us to obtain arterial-phase MR angiograms of the carotid and vertebral arteries. The study included 35 patients with suspected lesions of the neck in whom the MR Smartprep technique was used for MR angiography performed with a 1.5-T superconducting system. The tracker volume was placed primarily in the middle part of the right common carotid artery. The imaging volume was placed in a coronal direction to include the carotid and vertebral arteries from the aortic arch to the skull base. A centric phase-ordering scheme was used. Imaging times were 20 to 38 seconds for 14 patients and 11 to 16 seconds for 21 patients. By using a smaller tracker volume and an imaging time of less than 16 seconds, we were able to achieve a 100% successful triggering rate and to delineate selectively arterial-phase carotid and vertebral arteries with almost no venous contamination. Contract-enhanced 3-D MR angiography with the MR Smartprep technique was useful for showing arterial-phase carotid and vertebral arteries selectively.

Aorta, Thoracic↗
PubMed1998

[Dynamic magnetic resonance dacryocystography using half Fourier single shot fast spin echo sequence].

Dynamic magnetic resonance dacryocystography (MRD) was implemented using 1.5T superconductive imager with a standard head coil. Prior to MRD, a pair of polyethylene microcatheters were inserted into the lower lacrimal canaliculi. Injecting a mixture of 6 ml of saline and 4 ml of xylocaine (0.5%) as a substitute for contrast medium, repeated measurement of thick section heavily T2 weighted image using half Fourier single shot fast spin echo (SSFSE) sequence was performed. MRD could well depict the pathologies of the lacrimal sac and the lacrimal duct in five cases of epiphora. It pinpointed the level of lacrimal duct obstruction, which was confirmed by both X-ray dacryocystography and intraoperative findings. Dynamic MRD is a reliable method of diagnosing nasolacrimal duct obstruction without using ionizing radiation or chemical contrast medium.

Aged↗
PubMed1998

Microsatellite instability in breast cancers with special reference to patients' age and bilaterality.

We examined breast cancers from 67 female patients to ascertain the possible correlation between RER or LOH status, age and bilaterality using eight microsatellite markers on chromosomes 2p, 3p, 16q, 17p and 17q. The frequencies of RER in young patients (25-35 years old), patients with double primary disease (43-77 years old) and patients with contralateral metastases (46-72 years old) were 35%, 63%, and 80%, respectively, while that in elderly patients (60-81 years old) was 0%. In contrast, there were no statistically significant differences in the frequency of LOH between these groups. Our results suggest that RER might play an important role in the occurrence of breast cancer at a younger age and in bilateral breast cancer.

Adult↗
PubMed1998

[Successful removal of a left ventricular fibroma in a 10-year-old patient].

A 10-year-old girl with negative T wave in leads I, II, III, aVF, and V2-6 in the ECG was examined. The two-dimensional echocardiogram and the MRI revealed that she had a tumor in the free wall near the apex of the left ventricle. We removed the intramural fibroma (50 x 35 x 30 mm) of the left ventricle under cardiopulmonary bypass very carefully not to perforate the left ventricular cavity. After the removal, the defect was repaired by the sutures of the myocardial layers so that the volume inside the left ventricle could be kept and its shape could be maintained. She has been doing well without any trouble for 5 months after the operation.

Cardiac Surgical Procedures↗
PubMed1998

Characteristics of tolerance to somatic and visceral antinociception after continuous epidural infusion of morphine in rats.

UNLABELLED: A continuous epidural infusion of morphine may cause a complicated tolerance to develop, depending on the spinal and supraspinal sites. We designed this study to clarify the characteristics of the tolerance to somatic and visceral antinociception after epidural morphine infusion. Rats received epidural infusion of morphine at the rates of 50 or 100 microg kg(-1) h(-1), or isotonic sodium chloride solution for 7 days. The tail-flick (TF) test and colorectal distension (CD) test were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests were performed on Days 1, 2, 3, 4, and 7. After 7 days, time-response curves after epidural morphine (10 microg) or intraperitoneal morphine (3 mg) challenge tests were conducted to assess the magnitude of tolerance. Epidurally infused morphine significantly increased percent maximal possible effects (%MPEs) (P < 0.05) in both the TF and CD tests, depending on the concentration of morphine. In the epidural morphine challenge test, increases in %MPEs were significantly attenuated (P < 0.05) in the morphine-infused group compared with the isotonic sodium chloride solution-infused group. The increases in %MPEs in the intraperitoneal challenge test were also attenuated in the morphine-infused group. We conclude that morphine tolerance to both somatic and visceral antinociception develops rapidly during epidural infusion and is based on the development of tolerance at the systemic, as well as the epidural, level. IMPLICATIONS: A continuous epidural infusion of morphine rapidly induces tolerance to visceral and somatic antinociception in rats. This development is based on the development of tolerance at the systemic, as well as the epidural, level.

Analgesics, Opioid↗
PubMed1998

[Maximum intensity projection (MIP) and multiplanar reformation (MPR) for post-processing cholangiopancreatographic data set--clinical application and pitfalls].

Maximum intensity projection (MIP) and multiplanar reformation (MPR) are the most frequently used algorithms for MR cholangiopancreatography (MRCP). The MIP allows three dimensional overview of the pancreatic and biliary system. Because of its resemblance to ERCP images, MIP reconstruction is widely accepted by clinicians. In spite of its usefulness, MIP may be misleading without a proper reference to source images or a guidance of MPR. Opacification defects that reflect intra-ductal or intra-cystic pathologies are notably erased through the process of MIP reconstruction. Diagnosis based only on MIP images is therefore not clinically feasible. A combined use either of multisection images, or at least source images, is essential. The MPR on the other hand, enables an investigation of the details of the intra-ductal or intra-cystic pathologies. Detailing with MPR and surveying with MIP work together in interpreting MRCP data set.

Biliary Tract↗
PubMed1997

Independent photoreceptive circadian clocks throughout Drosophila.

Transgenic Drosophila that expressed either luciferase or green fluorescent protein driven from the promoter of the clock gene period were used to monitor the circadian clock in explanted head, thorax, and abdominal tissues. The tissues (including sensory bristles in the leg and wing) showed rhythmic bioluminescence, and the rhythms could be reset by light. The photoreceptive properties of the explanted tissues indicate that unidentified photoreceptors are likely to contribute to photic signal transduction to the clock. These results show that autonomous circadian oscillators are present throughout the body, and they suggest that individual cells in Drosophila are capable of supporting their own independent clocks.

Animals↗
PubMed1997

Spatial and temporal expression of the period and timeless genes in the developing nervous system of Drosophila: newly identified pacemaker candidates and novel features of clock gene product cycling.

The circadian timekeeping system of Drosophila functions from the first larval instar (L1) onward but is not known to require the expression of clock genes in larvae. We show that period (per) and timeless (tim) are rhythmically expressed in several groups of neurons in the larval CNS both in light/dark cycles and in constant dark conditions. Among the clock gene-expressing cells there is a subset of the putative pacemaker neurons, the "lateral neurons" (LNs), that have been analyzed mainly in adult flies. Like the adult LNs, the larval ones are also immunoreactive to a peptide called pigment-dispersing hormone. Their putative dendritic trees were found to be in close proximity to the terminals of the larval optic nerve Bolwig's nerve, possibly receiving photic input from the larval eyes. The LNs are the only larval cells that maintain a strong cycling in PER from L1 onward, throughout metamorphosis and into adulthood. Therefore, they are the best candidates for being pacemaker neurons responsible for the larval "time memory" (inferred from previous experiments). In addition to the LNs, a subset of the larval dorsal neurons (DNLs) expresses per and tim. Intriguingly, two neurons of this DNL group cycle in PER and TIM immunoreactivity almost in antiphase to the other DNLs and to the LNs. Thus, the temporal expression of per and tim are regulated differentially in different cells. Furthermore, the light sensitivity associated with levels of the TIM protein is different from that in the heads of adult Drosophila.

Aging↗
PubMed1997

Distinct substrate specificities of five human alpha-1,3-fucosyltransferases for in vivo synthesis of the sialyl Lewis x and Lewis x epitopes.

Five different human alpha-1,3-fucosyltransferase genes, the Fuc-TIII, Fuc-TIV, Fuc-TV, Fuc-TVI and Fuc-TVII genes, have been cloned to date. We transfected HeLa cells and Namalwa cells with each of the five different genes, and established a series of stable cloned transformant cells. Thin-layer chromatography immunostaining analysis revealed that all five enzymes were able to synthesize sialyl Lewis x (sLe(x)) epitopes on glycolipids in HeLa cells, but each enzyme showed a different preference as to the carbohydrate chain length on glycolipids as acceptor substrates. Fuc-TIII and Fuc-TV showed very similar patterns of sLe(x) positive bands, which indicated that the enzymes have similar acceptor substrate specificities. Fuc-TVI exhibited a little different pattern from those of the former two enzymes. Fuc-TIV and Fuc-TVII showed similarity in the positive bands, however, their patterns were quite different from those of the former three enzymes. Four enzymes except for Fuc-TVII were able to synthesize the Lewis x (Le(x)) epitope on glycolipids in HeLa cells. Fuc-TV alone showed a little different pattern of Le(x) positive bands from those of the other three enzymes. Flow cytometric analysis of HeLa cells and Namalwa cells again demonstrated the similar specificities of Fuc-TIII and Fuc-TV. They exhibited similar stronger staining with FH6 (anti-sLe(x)) antibodies than that with the other enzymes. A phylogenetic tree of the five enzymes constructed using the neighbor-joining method showed good agreement with the similarities in the enzyme substrate specificity.

Burkitt Lymphoma↗
PubMed1997

Wide variety of point mutations in the H gene of Bombay and para-Bombay individuals that inactivate H enzyme.

The H genes, encoding an alpha1,2fucosyltransferase, which defines blood groups with the H structure, of four Bombay and 13 para-Bombay Japanese individuals were analyzed for mutations. Four Bombay individuals were homologous for the same null H allele, which is inactivated by a single nonsense mutation at position 695 from G to A (G695A), resulting in termination of H gene translation. The allele inactivated by the G695A was designated h1. The other 13 para-Bombay individuals possessed a trace amount of H antigens on erythrocytes regardless of their secretor status. Sequence analysis of their H genes showed four additional inactivated H gene alleles, h2, h3, h4, and h5. The h2 allele possesed a single base deletion at position 990 G (990-del). The h3 and h4 alleles possessed a single missense mutation, T721C, which changes Tyr 241 to His, and G442T, which changes Asp148 to Tyr, respectively. The h5 allele possessed two missense mutations, T460C (Tyr154to His) and G1042A (Glu348to Lys). The h2, h3, h4, and h5 enzymes directed by these alleles were not fully inactivated by the deletion and the missense mutations expressing some residual enzyme activity resulting in synthesis of H antigen on erythrocytes. Thirteen para-Bombay individuals whose erythrocytes retained a trace amount of H antigen were determined to be heterozygous or homozygous for at least one of h2, h3, h4, or h5 alleles. This clarified that the levels (null to trace amount) of H antigen expression on erythrocytes of Bombay and para-Bombay individuals are determined solely by H enzyme activity. These mutations found in the Japanese H alleles differ from a nonsense mutation found in the Indonesian population. To determine the roles of the H, Se, and Le genes in the expression of H antigen in secretions and Lewis blood group antigen on erythrocytes, the Lewis and secretor genes were also examined in these Bombay and para-Bombay individuals. The Lewis blood group phenotype, Le(alpha- b+), was determined by the combinatorial activity of two fucosyltransferases, the Lewis enzyme and the secretor enzyme, and the secretor status was solely determined by the secretor enzyme activity, not by H enzyme activity. Bombay individuals were confirmed to be homozygous for the inactivated H and Se genes. As expected from the very low frequency of Bombay and para-Bombay individuals in the population, ie, approximately one in two or 300,000, the H gene mutations were found to be very variable, unlike the cases of the point mutations in the other glycosyltransferase genes; the ABO genes, the Lewis gene, and the secretor gene.

Adenine↗
PubMed1997

Reduction of radiation-induced xerostomia in nasopharyngeal carcinoma using CT simulation with laser patient marking and three-field irradiation technique.

PURPOSE: Tumor control and reduction of postirradiation xerostomia in patients with nasopharyngeal carcinoma (NPC) using the three-field irradiation technique based on the CT-based simulation with laser patient marking was investigated. METHODS AND MATERIALS: Seventy-eight patients with NPC were consecutively treated between 1983 and 1993. In 33 patients treated before 1987, target volume was determined using a conventional x-ray simulator with a reference of CT images, and the primary site was treated by the conventional parallel-opposed two-field technique (Group I). In 45 patients treated from 1987, target volume was determined using a CT simulator slice by slice, the treatment field was projected onto the patient's skin by a laser beam projector mounted on a C-arm, and the primary site was irradiated by a three-fields (anterior and bilateral) technique (Group II). In Group II, the shape of each field was determined using a beam's eye view to reduce the dose to the bilateral parotid glands. The three-field technique reduced the dose to the superficial lobe of parotid gland to about two-thirds of the dose given by the two-field technique. Radiation-induced xerostomia was evaluated by clinical symptoms and radioisotope sialography. RESULTS: The 5-year survival rate and disease-free survival rate were 46.6 and 31.2% in Group I, and 46.8 and 46.5% in Group II. A large variation in the volume of parotid glands were demonstrated, ranging from 9 cm3 to 61 cm3 among patients treated with CT simulation. Forty percent of the patients in Group II showed no or mild xerostomia, whereas all of the patients in Group I showed moderate to severe xerostomia (p < 0.01). The radioisotope sialography study showed that the mean secretion ratio by acid stimulation was improved from 3.8% in the Group I to 15.2% in the Group II (p < 0.01). CONCLUSIONS: CT simulation was useful to determine the size and shape of each field to reduce the dose to the parotid gland, of which size varies largely among individual patients. The three-field technique based on CT simulation with laser patient markings is suggested to result in superior complication-free survival in terms of salivary dysfunction than did the conventional two-field technique with x-ray simulatior for NPC.

Adolescent↗
PubMed1997

Neurotrophic 3,9-bis[(alkylthio)methyl]-and-bis(alkoxymethyl)-K-252a derivatives.

A series of 3,9 disubstituted [(alkylthio)methyl]- and (alkoxymethyl)-K-252a derivatives was synthesized with the aim of enhancing and separating the neurotrophic properties from the undesirable NGF (trk A kinase) and PKC inhibitory activities of K-252a. Data from this series reveal that substitution in the 3- and 9-positions of K-252a with these groups reduces trk A kinase inhibitory properties approximately 100- to > 500-fold while maintaining or in certain cases enhancing the neurotrophic activity. From this research, 3,9-bis[(ethylthio)methyl]-K-252a (8) was identified as a potent and selective neurotrophic agent in vitro as measured by enhancement of choline acetyltransferase activity in embryonic rat spinal cord and basal forebrain cultures. Compound 8 was found to have weak kinase inhibitory activity for trk A, protein kinase C1 protein kinase A, and myosin light chain kinase. On the basis of the in vitro profile, 8 was evaluated in in vivo models suggestive of neurological diseases. Compound 8 was active in preventing degeneration of cholinergic neurons of the nucleus basalis magnocellularis (NBM) and reduced developmentally programmed cell death (PCD) of female rat spinal nucleus of the bulbocavernosus motoneurons and embryonic chick lumbar motoneurons.

Animals↗
PubMed1997

Inhibition of rat prostate carcinogenesis by a 5alpha-reductase inhibitor, FK143.

BACKGROUND: Androgen levels in the prostate may influence carcinogenesis in this organ. Inhibitors of the enzyme 5alpha-reductase block conversion of testosterone to the more active androgen dihydrotestosterone. The use of a 5alpha-reductase inhibitor, finasteride, in the chemoprevention of prostate cancer is being evaluated in a clinical trial. PURPOSE: This study was conducted to determine if a 5alpha-reductase inhibitor, FK143, inhibits the development of prostate cancer in rats. METHODS: Male ACI/Seg rats, which spontaneously develop prostate cancer, were randomly assigned at 80 weeks of age to receive one of three diets (n = 35/group) containing 0 (i.e., control group), 20, or 200 ppm FK143. At 140 weeks of age, the animals were killed, and the prostates were removed and examined for histopathologic features in addition to being assayed for androgen concentrations. Two-sided statistical tests were used to calculate all P values. RESULTS: The incidence of prostate carcinoma in the control group was 62.9% (22 of 35 rats); in the group fed the 20 ppm FK143-containing diet, it was 45.7% (16 of 35); and in the group fed the 200 ppm FK143-containing diet, it was 67.6% (23 of 34) (overall, P = .153). The corresponding incidences of macroscopic lesions were 17.1% (six of 35 rats), 0% (none of 35), and 23.5% (eight of 34), respectively (overall, P = .004). The incidence of macroscopic lesions in the prostates of rats in the 20-ppm diet group was significantly lower than that in the control group (P = .029) or that in the 200-ppm diet group (P = .003). Intraprostatic dihydrotestosterone content was significantly lower in rats in the groups fed diets containing 20 or 200 ppm FK143 (mean values: 4.51 and 4.33 pg/mg wet weight of prostate tissue, respectively) than in the control group (6.10 pg/mg) (overall, P<.001); by contrast, testosterone was higher in the 200-ppm diet group (2.09 pg/mg) than in the control group (1.08 pg/mg) or the 20-ppm diet group (1.21 pg/mg) (overall, P<.001). CONCLUSIONS: FK143, when fed to rats at 20 or 200 ppm, significantly reduced the level of dihydrotestosterone in their prostate tissue. However, the incidence of macroscopic cancer in the prostate was suppressed in rats consuming the 20 ppm FK143-containing diet but not in those consuming the 200-ppm diet. The lack of dose dependence for the chemopreventive activity of FK143 may be explained by the reciprocal increase of tissue testosterone in the 200-ppm diet group. IMPLICATIONS: The 5alpha-reductase inhibitor FK143 may, at specific doses, reduce the incidence of spontaneously developing prostate cancer; however, whether these findings in rats will apply to humans remains to be determined.

5-alpha Reductase Inhibitors↗
PubMed1997

Multiple haemorrhagic brain metastases from papillary thyroid cancer.

We report a 40-year-old woman, who initially developed cerebellar symptoms, with multiple hemorrhagic brain metastases from a papillary thyroid cancer. Intracranial masses gave heterogeneous high signal on T1-weighted and T2-weighted images, hemosiderin rims on the latter. Some of the tumors showed contrast enhancement. Metastatic thyroid cancer is a consideration in a patient with multiple hemorrhagic masses.

Brain↗