Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 325 records · Page 18Linked to original sources

PubMed1994

Poor outcome in patients with advanced stage neuroblastoma and coincident opsomyoclonus syndrome.

BACKGROUND: Most patients with neuroblastoma who present with opsomyoclonus have a good prognosis. Neuroblastomas from such patients have been reported to contain a single copy of the N-myc gene. The authors describe three cases of patients with advanced neuroblastoma with opsomyoclonus, which had poor outcomes despite multimodal therapy. METHODS: Amplification and expression of the N-myc gene were examined in these three primary tumors using Southern and Northern blot analyses. Then, flow cytometric analysis of the cellular DNA contents of these tumors was performed. RESULTS: N-myc amplification was observed in two tumors and N-myc RNA overexpression was observed in all three. Analysis of the cellular DNA contents of the tissue specimens revealed hyperdiploidy in all three tumors; one had a triploid index and the other two had hypotetraploid indexes. CONCLUSIONS: These findings suggest that a poor outcome for patients with opsomyoclonus may be associated with N-myc gene activation (amplification and/or overexpression) and that a hyperdiploid tumor is not always associated with a good prognosis.

Adrenal Gland Neoplasms↗

PubMed1994

Sequence of the cellular T-DNA in the untransformed genome of Nicotiana glauca that is homologous to ORFs 13 and 14 of the Ri plasmid and analysis of its expression in genetic tumours of N. glauca x N. langsdorffii.

A region homologous to the TL-DNA of Agrobacterium rhizogenes was previously detected in the genome of untransformed Nicotiana glauca and designated cellular T-DNA (cT-DNA). Subsequently, part of this region was sequenced and two genes, which corresponded to rolB and rolC and were named NgrolB and NgrolC, were found. We have now sequenced a region of the cT-DNA other than the region that includes NgrolB and C and we have found two other open reading frames (ORFs), NgORF13 and NgORF14. These ORFs correspond to ORFs 13 and 14 of the TL-DNA of A. rhizogenes and exhibit a high degree of homology to these ORFs, without having a nonsense codon. We have not found any sequence homologous to rolD (ORF15). The two genes, NgORF13 and 14, as well as the NgrolB and C genes, are expressed in genetic tumors of hybrids between N. glauca and N. langsdorffii but not in leaf tissues of the hybrid.

Amino Acid Sequence↗

PubMed1994

Light suppresses the activity of serotonin-immunoreactive neurons in the optic lobe of the swallowtail butterfly.

Intracellular recordings and stainings were made from 5-HT-immunoreactive neurons with a large soma at the anterior edge of the second optic neuropile of the swallowtail butterfly Papilio xuthus. The neurons have a dendritic arborization in the third optic neuropile and project axonal processes to the first optic neuropile and the dorsal protocerebrum. The neurons discharged impulses in the dark and the impulse discharge was inhibited by illumination of the ipsilateral eye. The anatomical and physiological profiles suggest that the neurons may have a role in controlling the light-dark adaptation or the overall activity of the optic lobe and the midbrain.

Animals↗

PubMed1994

Suppression of metastasis of rat prostatic cancer by introducing human chromosome 8.

In previous allelotype analyses of human prostatic cancer specimens, allelic loss on the short arm of chromosome 8 is frequently observed. However, it is still unclear whether this allelic loss is an initial event or a later one in development of prostatic cancer. Our previous studies demonstrate that introduction of human chromosome 11 into highly metastatic rat prostatic cancer cells results in suppression of metastatic ability without suppression of the in vivo growth rate or tumorigenicity of the hybrid cells (T. Ichikawa et al. Cancer Res., 52: 3486-3490, 1992). To clarify the role of human chromosome 8 in prostatic cancer, this chromosome was introduced into highly metastatic rat prostatic cancer cells using microcell-mediated chromosome transfer. Introduction of human chromosome 8 resulted in suppression of metastatic ability of the microcell hybrids, whereas no suppression of the in vivo growth rate or tumorigenicity was observed. These results demonstrate that human chromosome 8 contains metastasis suppressor gene(s) for prostatic cancer derived from a rat. These also suggest that human chromosome 8 has an important role in development of prostatic cancer.

Animals↗

PubMed1994

[Usefulness of dynamic subtraction CT for intracranial high density lesions].

Dynamic subtraction CT (DSCT) using a high speed Rotate/Rotate CT Scanner (Toshiba Xforce) was performed on 10 patients with intracranial high density lesions such as brain tumors and vascular malformations. In comparison with conventional contrast enhanced CT, the technique of dynamic subtraction CT enabled us to evaluate more clearly the contrast enhancement of high density lesions and to separate more easily the lesions from hematoma and calcification, which are shown as avascular areas. The results suggest that DSCT is a valuable method for evaluating the contrast enhancement of intracranial high density lesions.

Adult↗

PubMed1994

[Distinction between adrenal adenomas and metastases using 0.5 Telsa MR imaging: diagnosis with out-of-phase T2*-weighted gradient-field-echo image].

The purpose of this study was to investigate the ability of MR imaging with a 0.5-T apparatus to distinguish adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 non-hyperfunctioning adenomas, 5 hyperfunctioning) and 23 adrenal metastases (14 from lung, 5 liver, 3 colon, and 1 stomach cancer). The signal intensity (SI) ratio (adrenal tumor/liver) on T1-, T2-, and T2*-weighted MR images was calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21/23, 91%) than on T2-weighted images (15/23, 65%). In conclusion, T2*-weighted images were better than routine T2-weighted images in distinguishing adrenal adenomas from adrenal metastases. The reason could be that the total signal intensity of adrenal adenomas which contained some fat components decreased on T2*-weighted images due to an out-of-phase effect.

Adenoma↗

PubMed1994

Reorganization of visual interneurons during metamorphosis in the swallowtail butterfly Papilio xuthus.

The metamorphic fate of larval visual interneurons in the swallowtail butterfly Papilio xuthus has been examined by using reduced silver impregnation and immunocytochemistry of gamma-amino butyric acid (GABA). Visual interneurons in the second larval optic neuropile (medulla) can be followed throughout metamorphosis because of large somata located in the anterior edge of the imaginal medulla. Ten to 12 neurons in the larval medulla were immunoreactive to a GABA-antiserum. They arborize in the larval medulla and extend dendritic processes to the first larval optic neuropile (lamina). After pupation, the medulla neurons lose GABA-immunoreactive larval processes and differentiate new processes that enter tangentially into the developing imaginal medulla. Axons of the surviving larval neurons follow an optic tract between the lobula and the lobula plate and extend to the lateral area of the protocerebrum. Thus, larval visual interneurons are incorporated into the imaginal optic lobe and may play a new role in the visual processing of the butterfly.

Animals↗

PubMed1994

Enhancing effect of high dietary iron on lung tumorigenesis in mice.

In our previous reports we indicated that oxidative stress on pulmonary nuclei caused by oxy radicals could be involved in glycerol-enhanced lung tumorigenesis in ddY mice treated with 4-nitroquinoline 1-oxide (4NQO). This study was undertaken to estimate if dietary iron could act as a stimulating factor on lung tumorigenesis in mice treated with 4NQO plus glycerol. Feeding excessive iron to mice treated with these agents significantly increased nuclear thiobarbituric acid reactive substances (TBARS) and DNA single strand breaks (DNA-SSB) in the lungs as compared with mice fed adequate iron 4 weeks after 4NQO injection. Nuclear non-haem iron level in mice fed excessive iron was also higher than the level in mice fed adequate iron. Twenty-three weeks after 4NQO injection (at the end of this experiment) the supply of excessive iron for 4 and 23 weeks after 4NQO injection stimulated the development of lung tumors in mice treated with 4NQO plus glycerol. These results suggest that a high dietary iron level acts as a stimulating factor on lung tumorigenesis in mice treated with 4NQO plus glycerol.

4-Nitroquinoline-1-oxide↗

PubMed1994

Effects of acid-inhibitory antiulcer drugs on mucin biosynthesis in the rat stomach.

The effects of the anti-acid secretory agents, cimetidine (N-cyano-N'-methyl-N"-(2-([(5-methyl-1H-imidazol-4-yl)methyl]thio)ethyl) guanidine), ranitidine (N-(2-(((-5-[(dimethylamino)methyl]-2-furanyl)methyl)thio)ethyl)-N'-meth yl- 2-nitro-1,1-ethene-diamine), roxatidine (2-acetoxy-N-(3-[m-(1-piperidinylmethyl)phenoxy]-propyl) acetamide hydrochloride), FRG-8813 (2-(furfurylsulfinyl)-N-(4-[4-(piperidinomethyl)-2-pyridyl]o xy-(z)-2- butenyl)acetamide), omeprazole (5-methoxy-2-([(4-methoxy-3,5-dimethylpyridinyl)methyl]sulfinyl)- 1H-benzimidazole), and NC-1300-O-3 (2-([2-(isobutylmethylamino)benzyl]sulfinyl)-1H- benzimidazole), on mucin biosynthesis were studied in rat gastric mucosa by using an organ culture technique. [3H]Glucosamine incorporation was stimulated in the corpus region by the histamine H2 receptor antagonists which have a six-membered aromatic ring, roxatidine and FRG-8813, and the new H+,K(+)-ATPase inhibitor, NC-1300-O-3. Thus, these drugs not only inhibit acid secretion but may also promote gastric mucosal protective actions. The present observations also demonstrate that the determination of mucin biosynthesis may be a useful tool for evaluation of mucosal protective activity.

Animals↗

PubMed1994

Natural course of human benign prostatic hyperplasia with relation to urinary disturbance.

To examine the natural course of human benign prostatic hyperplasia (BPH), cases in health care examination with or without slight urinary symptoms were examined by echography. In comparison with these cases, the size of the prostate was examined in patients who received prostatectomy. Prostatic sizes of health care cases varied widely along with increasing age, but could be divided into two groups: increasing or no-change. According to serial determinations of prostatic sizes in the increasing group, the annual growth rate of the prostate was calculated as 1.65 +/- 1.13 and 0.85 +/- 0.44 g in men < 65 years old and in men > or = 65 years old, respectively. Distribution of prostatic sizes as a function of age in health care cases was similar to that in operated patients, showing that the size was not correlated with urinary symptoms or surgical indication. Since uroflow rates decreased along with increasing age in the no-change group of operated patients, aging was a factor in deterioration of uroflow. Between the increasing and the no-change groups in health care cases, differences were found in total cholesterol and neutral fat in serum, in addition to gamma-seminoprotein; the latter may be due to differences in the size of the prostate. In conclusion, natural course of the prostatic hyperplasia is separated into two groups, increasing and no-change. Occurrence of urinary symptoms does not simply relate to an increase in prostatic weight but, at least in part, to the aging process.

Adult↗

PubMed1994

Inhibition of growth and increase of acid phosphatase by testosterone on androgen-independent murine prostatic cancer cells transfected with androgen receptor cDNA.

Most androgen-unresponsive prostatic cancer cells are found to lack androgen receptor (AR). To clarify the role of AR in the process of the progression from androgen-dependent to androgen-unresponsive tumor, the AR gene was transfected into an AR-negative rat prostatic cancer cell line CUB-II. AR-transfectant cells expressed AR mRNA and showed binding to R1881. AR was found in nuclei of AR-transfectant cells by histochemical examination. Therefore, AR-transfectant cells were considered to contain functional AR. The growth of AR-transfectant cells was markedly inhibited in culture in the presence of testosterone, and the effect of testosterone was reduced by simultaneous addition of flutamide. Moreover, tumors inoculated with AR-transfectant cells in male mice showed much slower growth than those in females. The tumors of AR-transfectant cells in mice consisted of slightly larger spindle-shaped cells when compared to those of CUB-II cells. Moreover, AR-transfectant cells contained a few polynuclear giant cells. Since CUB-II cells contained acid phosphatase (AcP) activity, the addition of testosterone in culture increased AcP activity of AR-transfectant cells. It is concluded that resumption of androgen-dependent processes reduces the growth rate accompanying changes of phenotype.

Acid Phosphatase↗

PubMed1994

Pharmacokinetic study of mannitol in subjects with increased ICP.

Six human subjects received mannitol as an intravenous dip (DIV) infusion. In each subject, the concentration of mannitol and serum osmolality were rapidly elevated during mannitol administration and reached the maximum at the end of mannitol administration. Then, it exponentially decreased. There was a strong positive correlation between mannitol concentration and extrinsic serum osmolality. The integrated values of mannitol concentration difference between the central (Cc) and the peripheral compartment (Pc) correlated with the changes of ICP reduction during mannitol administration. The results indicate that the changes of ICP reduction depend on the mannitol concentration difference between Cc and Pc.

Adult↗

PubMed1994

Analysis of p53 gene mutations in low- and high-grade astrocytomas by polymerase chain reaction-assisted single-strand conformation polymorphism and immunohistochemistry.

Using polymerase chain reaction-assisted single-strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses, mutations in the p53 tumor suppressor gene were examined in 19 low- and high-grade gliomas. By PCR-SSCP and nucleotide analyses, p53 gene mutation was seen in 7 gliomas. Out of the 7 mutations, 3 were located at the CpG site of the previously proposed hot-spot codons 248 and 273, 2 were at codons 171 and 214 and the other 2 were in intron 5, 1 at the splice acceptor site and the other in the vicinity of the splice donor site. The latter 4 mutations have not, or only rarely, been observed in gliomas or in other tumors. However, their effect on the structural and functional alteration of the p53 protein was suggested by positive intranuclear p53 immunostaining in neoplastic cells in 3 mutations including the 1 at the splice acceptor site. In connection with glioma grading, the p53 gene mutation was shown to have occurred in both low- and high-grade gliomas, often in most of the neoplastic cells, as suggested by lack of distinct normal bands and ladders in SSCP and direct sequencing, respectively. The absence of recurrence and malignant transformation over a considerably long postoperative time in our low-grade glioma cases suggested that the p53 gene mutation might not be sufficient for the progression from low- to high-grade gliomas. The frequency of detection of mutation was 7/19(37%) by PCR-SSCP, 8/19(42%) by immunohistochemistry and 10/19(53%) by both methods. The results of PCR-SSCP and immunohistochemistry were consistent in 14 cases (73.7%), but not in 5 cases(26.3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytoma↗

PubMed1994

Comparative study on factors regulating the level of oxidative stress toward pulmonary nuclei in two different strains of mice.

1. The levels of active oxygen formed and thiobarbituric acid reactive substances (TBARS) in pulmonary nuclei of A/J strain were higher than those in the nuclei of ddY strain, while nuclear alpha-tocopherol level in the lungs of the former strain was lower than the the level in the latter strain. 2. Unsaturation index (UI) of nuclear fatty acids and oxidative damage to DNA in the lungs of A/J strain were higher than those in the lungs of ddY strain. 3. These results suggest that the capacity of nuclear active oxygen formation, nuclear alpha-tocopherol level and UI of nuclear fatty acids in the lungs can be main factors to regulate oxidative stress toward the pulmonary nuclei in the two strains of mice.

Animals↗

PubMed1994

Effects of the new histamine H2 receptor antagonist, FRG-8813, on gastric mucin in rats with or without acidified ethanol-induced gastric damage.

It is not presently well understood whether the histamine H2 receptor antagonist has a function other than the inhibition of gastric acid secretion, such as the effect on the gastric mucosal defence mechanism. In this paper, we report the effect of FRG-8813 (N-[4-[4-(piperidinylmethyl)pyridyl-2-oxy]-(Z)-2-butenyl]-2- (furfurylsulfinyl) acetamide), a new histamine H2 receptor antagonist, on the rat gastric mucin content with or without 0.15N HCl-ethanol (60 %)-induced gastric damage. The prior administration of FRG-8813 significantly inhibited the occurrence of macroscopically observable hemorrhagic lesions induced by the acidified ethanol treatment. Using a newly developed biochemical method, the mucin content of the deep corpus and antral mucosa of the acidified ethanol-treated animals was significantly reduced to 50% and 32% of the control, respectively. These reductions were inhibited by the pretreatment with FRG-8813. Total mucin content in the entire stomach recovered to about 80% of the control value after pretreatment with FRG-8813. A single oral administration of FRG-8813 (30 mg/kg) caused no significant change in the total mucin content, but mucin in the adherent mucus gel layer selectively and significantly increased to 250% of the control. These results suggest that FRG-8813 not only inhibits acid secretion but may also affect the gastric mucosal defensive mechanism as well.

Acetamides↗

PubMed1994

Abdominal wall desmoid mimicking intra-abdominal mass: MR features.

A case of abdominal wall desmoid which enlarged toward the liver and mimicked an intra-abdominal tumor is presented. T*2-weighted MR images clearly demonstrated the tumor's continuity with the rectus abdominis muscle. The case presented suggests MRI may provide more valuable information concerning the origin of a right-upper-quadrant mass than CT does. However, the nature of the signals and attachment which this case showed were so unusual for desmoids that this case has not been diagnosed accurately.

Abdominal Muscles↗

PubMed1994

Decrease in vitamin E levels in the bone marrow of mice receiving whole-body X-ray irradiation.

Mice were subjected to whole-body x-ray irradiation, and changes in vitamin E content and lipid peroxide levels in various tissues were examined. When mice were irradiated with 6 Gy, vitamin E content (per mg protein) in the bone marrow began to decrease 3 h later and a marked decrease to the level of 30% of that of the controls was observed on day 2. Concomitant with the decrease of vitamin E, an increase of lipid peroxide levels was also observed in the bone marrow. On day 2 after an exposure to doses ranging from 1 to 10 Gy, a dose-dependent decrease of vitamin E and an increase of lipid peroxide levels were observed in the bone marrow with a dose of 3 Gy or more. In contrast, neither a decrease of vitamin E nor an increase of lipid peroxide levels was observed in the liver, kidney, spleen, and testes even with an exposure of up to 10 Gy. After the irradiation, glutathione in the bone marrow decreased, while that in the liver increased. These results suggest that the bone marrow is more highly susceptible to oxidative damage induced by radiation than other tissues.

Animals↗

PubMed1994

The urodynamic status during psychogenic erection in a patient with a conus medullaris injury. Case report.

The urodynamic status of a 24 year old male patient with psychogenic erection who sustained a conus medullaris lesion from a burst fracture of the first lumbar vertebra is reported. During the initial measurement the external urinary sphincter pressure began to rise from the base pressure of 35 cm H2O 5 seconds after the beginning of audiovisual sexual stimulation and reached the peak of 110 cm H2O. In parallel, the bladder neck pressure gradually rose from its base pressure of 5 cm H2O to a maximal pressure of 115 cm H2O and then ejaculation occurred. The difference is no more than 5 cm H2O and this small difference in pressure inhibits retrograde ejaculation.

Adult↗