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Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 271 records · Page 15Linked to original sources
PubMed1996

Relationship between grade of varicocele and the response to varicocelectomy.

BACKGROUND: Although several studies indicate that larger varicoceles are associated with greater impairment of spermatogenesis, others suggest that the response to surgery is independent of varicocele size. In order to elucidate these seeming contradictions, correlations between the preoperative evaluation of varicoceles and improvement in semen quality after varicocelectomy were investigated. METHODS: Forty men with left unilateral varicocele, followed for at least 6 months after varicocelectomy, were included in this study. The relationships between the grade of varicocele by palpation, Doppler examination, ultrasound, or scintigraphy were correlated with a postoperative improvement in sperm density or sperm motility. RESULTS: Greater improvement in sperm density was observed in the patients with a large varicocele graded by palpation or measured by ultrasound, and greater improvement in sperm motility was observed in the patients with high uptake of radioactivity in the left side by scrotal scintigraphy. CONCLUSION: An improvement in semen quality after varicocelectomy is greater in patients with a large varicocele than in the patients with a small one. The significance of surgical repair of a small varicocele should be reconsidered.

Angiography↗
PubMed1996

Characteristics of androgen-independent growth of androgen-responsive Shionogi carcinoma 115 cells.

BACKGROUND: The effects of castration on the biological features of an androgen-responsive carcinoma were examined in order to clarify the mechanism responsible for the relapse of an androgen-responsive carcinoma after androgen ablation therapy. METHODS: A well-characterized androgen-responsive mammary carcinoma, Shionogi carcinoma 115 (SC115), was used for these experiments. Male mice were examined for the effects of castration on the growth rate of the tumor, the number of androgen receptor-positive cells, and the karyotype of the SC115 tumors. Castration was performed 1 week prior to tumor transplantation, or 2 or 3 weeks after tumor transplantation. RESULTS: SC115 tumors did not develop when transplanted into castrated male mice. When castration was performed 2 weeks after transplantation, the tumor showed androgen-independent growth with temporary regression of growth rate. However, when castration was performed more than 3 weeks after transplantation, the tumor showed androgen-independent growth not associated with any temporal regression of growth rate. There were no significant differences in histological features or the number of androgen receptor-positive cells between SC115 tumors in untreated or castrated mice. To test whether SC115 tumors growing under androgen-deprived conditions became fully androgen-independent, SC115 tumors were transplanted in both male and female mice. A transplanted tumor piece grew progressively only in male mice. This indicates that the SC115 tumor maintains its androgen response in the next generation, even though growth of the tumor resumed after temporary suppression due to castration. Chromosomal analyses revealed no apparent cytogenetic changes in the SC115 tumors that resumed growth under androgen-deprived conditions. CONCLUSION: These results suggest that no gross changes in the number of androgen receptor-positive cells or karyotype are necessary for androgen-independent growth in this system once the size of tumor increased.

Androgens↗
PubMed1996

Effects of sigma ligands on the cloned mu-, delta- and kappa-opioid receptors co-expressed with G-protein-activated K+ (GIRK) channel in Xenopus oocytes.

1. Taking advantage of the functional coupling of the opioid receptors with the G-protein-activated K+ (GIRK) channel, we investigated the effects of sigma (sigma) ligands of various structural and pharmacological classes, (+)-N-allylnormetazocine ((+)-SKF10047) and (+)-cyclazocine, (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3PPP), 1,3-di-(2-tolyl)guanidine (DTG), carbetapentane and haloperidol, on the inward K+ current responses in Xenopus oocytes co-injected with each of the cloned mu-, delta- and kappa-opioid receptor mRNAs and the GIRK1 mRNA. 2. (+)-SKF10047 acted as a delta- and kappa-agonist (EC50 values (microM) = 0.618 and 0.652, respectively) and mu-antagonist (IC50 value (microM) = 8.51). (+)-Cyclazocine acted as a kappa-agonist and mu-antagonist (IC50 = 33.2). (+)-3PPP acted as a kappa-agonist (EC50 = 18.08 and a mu-antagonist. DTG acted as a mu- and kappa-agonist (EC50 = more than 30 and 14.88, respectively). Carbetapentane acted as a kappa-agonist and mu-antagonist (IC50 = 11.2). Haloperidol acted as a mu- and delta-agonist (EC50 = 5.683 and 7.389, respectively). 3. All currents induced by sigma ligands were reduced by 1 microM naloxone, an opioid receptor antagonist, and blocked by 300 microM Ba2+, a GIRK channel blocker. It was also indicated that the antagonism by naloxone at the delta-- and kappa-opioid receptors was weaker than that of naloxone at the mu-opioid receptor. The sigma ligands tested had no effect on the current responses in the oocytes injected with each of the opioid receptor mRNAs alone or with the GIRK1 mRNA alone. 4. We conclude that various sigma ligands directly interact with the cloned mu-, delta- and kappa-opioid receptors in Xenopus oocytes. Our results suggest that the effects of the sigma ligands may be partly mediated by the opioid receptors.

Animals↗
PubMed1996

The F wave disappears due to impaired excitability of motor neurons or proximal axons in inflammatory demyelinating neuropathies.

OBJECTIVES: Investigation of pathophysiology of F wave disappearance in demyelinating neuropathies. METHODS: The peripheral motor nerve conduction was studied by motor evoked potential (MEP) on transcranial magnetic stimulation as well as conventional nerve conduction studies before and after the treatment in 26 patients with inflammatory demyelinating neuropathies. In addition, serum antiganglioside antibodies in the acute or active stage were examined. RESULTS: The F wave was abolished in 10 patients. Seven of the 10 patients showed motor evoked potentials (MEPs) on transcranial magnetic stimulation that ranged from 1-4 mV. In six of them the F wave reappeared in the recovery stage, but the MEP size did not change. This may be caused by humoral factors, because the F wave reappeared immediately after plasma exchange or intravenous immunoglobulin treatment. A correlation of F wave disappearance with the presence of serum antiganglioside antibodies was found. CONCLUSIONS: The major pathophysiology of F wave disappearance in demyelinating neuropathies is impairment of motor neuron excitability or prolonged refractoriness of the most proximal axon for backfiring. The conventional interpretation that absent F waves suggest a conduction block at the proximal site is often inadequate.

Acute Disease↗
PubMed1996

Hepatocellular carcinoma: detection with double-phase helical CT during arterial portography.

Retrospective analysis of findings at double-phase helical computed tomography (CT) during arterial portography was performed in 42 hepatocellular carcinomas (HCCs) in 31 patients. Phase 1 scanning started 30-35 seconds after the beginning of injection of contrast material; phase 2 scanning started 10-18 seconds after the end of phase 1. The overall detection rate for HCCs was 83% (35 of 42) in phase 1, 81% (34 of 42) in phase 2, and 90% (38 of 42) for combined phase 1 and 2 findings.

Adult↗
PubMed1996

Squamous cell carcinoma arising in a verrucous epidermal nevus.

A 74-year-old Japanese male patient with squamous cell carcinoma arising in an epidermal nevus is described. The patient had widespread warty lesions involving large parts of the body since infancy. Recently, a nodular lesion appeared on the middle part of his back and increased in size. Histologically, the nodule was diagnosed as squamous cell carcinoma and the warty lesion showed the features of epidermal nevus. The nodular lesion was totally excised and the skin defect was covered with split-thickness skin grafting. To the best of our knowledge, this is the 16th patient with malignant change of a verrucous epidermal nevus.

Aged↗
PubMed1996

Ganglioneuroma: computed tomography and magnetic resonance features.

12 patients who had histological proven ganglioneuromas were investigated by computed tomography (CT) and magnetic resonance (MR) imaging. CT scans (n = 11), conventional spin-echo MR images (n = 10) and dynamic MR images (n = 5) were acquired. All lesions showed a well defined, oval shape. Five lesions (42%) showed calcification which was punctate in four and coarse in one on CT. CT attenuation was predominantly low in three of 10 (30%) and intermediate in the remaining seven (70%). In all lesions MR signals were mainly of low intensity on T1 weighted images (T1WI) and of high intensity on T2 weighted images (T2WI). Dynamic MR studies in five cases showed a lack of early enhancement but gradual increasing enhancement. One case had a ganglioneuroblastoma component which showed soft-tissue density and coarse calcifications on CT scans, MR images with intermediate intensity on T1WI and T2WI and early enhancement and little washout on dynamic MR images. In conclusion, ganglioneuroma typically shows punctate calcification and low attenuation on CT and marked hyperintensity on T2WI with gradual increasing enhancement on dynamic MR images. If a ganglioneuroma has atypical CT and MR features, coexistence of a malignant component should be considered.

Adolescent↗
PubMed1996

Phenotypic alterations of neuropeptide Y, vasoactive intestinal peptide and choline acetyltransferase in rat cultured chromaffin cells as effected by nerve growth factor and glucocorticoid.

We assessed changes in neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and choline acetyltransferase (ChAT) immunoreactivities when neonatal rat chromaffin cells were cultured in a medium containing nerve growth factor (NGF), or the synthetic glucocorticoid dexamethasone (DEX), examining whether their expression was correlated with the morphological changes induced by NGF and DEX. All of the chromaffin cells in culture were tyrosine hydroxylase (TH)-immunopositive regardless of whether they extended processes. TH-immunoreactive materials of NGF-treated chromaffin cells were distributed in all the cytoplasmic processes, even at the tips of growth cones. The percentage of NPY-positive chromaffin cells did not change markedly when treated with NGF or DEX throughout the 14 days in culture. The proportion of VIP-positive chromaffin cells increased gradually in the NGF-treated group and that of ChAT-positive cells in the group was similar to VIP. The morphological alterations induced by NGF were not correlated with the changes in proportions of NPY-, VIP- or ChAT-positive chromaffin cells. The percentages of VIP- or ChAT-immunopositive chromaffin cells in the NGF-treated group showed much greater increases than those in the DEX-treated group. These findings suggest that NGF might modulate the phenotypic changes of neuropeptides and amines in rat chromaffin cells.

Animals↗
PubMed1996

MR findings indicative of hemosiderin in giant-cell tumor of bone: frequency, cause, and diagnostic significance.

OBJECTIVE: We studied the frequency, cause, and diagnostic significance of MR findings indicative of large amounts of hemosiderin in giant-cell tumor of bone. MATERIALS AND METHODS: The clinical, MR, and histologic findings in 16 patients with giant-cell tumors of bone were reviewed. Eight tumors occurred in uncommon locations or in patients who were not in the usual age range; the other eight were more typical. Areas of decreased MR signal intensity considered to be caused by hemosiderin were identified. The number and distribution of RBCs within the tumor were studied histologically, and the presence of hemosiderin was determined on histologic sections made with iron stains. RESULTS: In 10 cases in which MR images showed areas of low signal intensity, large amounts of hemosiderin were noted histologically. The low-signal-intensity areas were nodular, zonal, whorled, or diffuse and occupied at least one fifth of the tumor volume. On histologic examination, many erythrocytes were in direct contact with the tumor cells, and the hemosiderin was seen in both mononuclear and multinuclear tumor cells. CONCLUSION: Hemosiderin is commonly seen on MR images of giant-cell tumors of bone (63%) and is probably related to the extravasated erythrocytes in the tumor and the phagocytic function of the tumor cells. This MR finding supports the diagnosis, even in giant-cell tumors in uncommon locations or in patients who are not in the typical age range.

Adult↗
PubMed1996

[Study on the sclerosing agent for the treatment of simple renal cysts].

BACKGROUND: The objective of this study is to evaluate the sclerosing agents for simple renal cysts. METHODS: Thirty-three renal cysts of 30 patients were treated by injection of sclerosing agents with the guidance of ultrasonography. Among them, 22 were treated with ethanol, and 11 with minocycline-hydrochloride (MINO). RESULTS: Clinical efficacy rates and volume reduction rates in each treatment group of ethanol or MINO, were 100% and 90.9%, and 91.2 +/- 13.1% (mean +/- SD) and 83.2 +/- 28.5%, respectively. Although several complications including pain and intoxication were observed in ethanol (47.4%), no complications were observed in MINO. CONCLUSION: The instillation of MINO into renal cysts is an effective, safe and simple treatment. It is thought that it can be the first choice of treatment for simple renal cysts.

Adult↗
PubMed1996

Metastasis suppressor genes for prostate cancer.

To examine the role of human chromosomes in the development of metastatic prostate cancer, we introduced a copy of human chromosomes into highly metastatic Dunning R-3327 rat prostatic cancer cells by microcell-mediated chromosome transfer. Each microcell hybrid clones containing human chromosomes 8, 10, 11, and 17, respectively, showed decreased ability to metastasize to the lung, without any loss of tumorigenicity. This finding demonstrates that these human chromosomes contain metastasis suppressor genes for prostate cancer. Spontaneous deletion of portions of human chromosomes was observed in human chromosome 10, 11, and 17 studies. In the human chromosome 8 study, irradiated microcell-mediated chromosome transfer was performed to enrich chromosomal arm deletions of human chromosome 8. Relationships between the size of human chromosomes introduced into microcell hybrid clones and the number of lung metastases produced by the clones were analyzed to determine which part of human chromosomes contained metastasis suppressor gene(s) for prostate cancer. Molecular and cytogenetic analyses of microcell hybrid clones demonstrated that metastasis suppressor genes on human chromosomes 8, 10, and 11 were located on 8p23-q12, 10q, 11p13-11.2, respectively. Further analyses are proposed to confirm the potentially useful advantage of this assay system to identify metastasis suppressor gene(s) for prostate cancer.

Animals↗
PubMed1996

[MR relaxation times in diffuse bone marrow disorders: evaluation of their clinical usefulness in differentiation between leukemia and anemia].

T1 and T2 relaxation time measurements of the femoral marrow were performed in 20 patients with acute myeloid leukemia (AML) and 9 patients with iron deficiency or other severe anemia who had shown diffuse abnormal signals on MR imaging of the femoral marrow. The ability of T1 and T2 values to differentiate between leukemic infiltration and hyperplastic hematopoietic marrow was evaluated. T1 and T2 ratios (T1 abnormal marrow/T1 normal marrow and T2 abnormal/T2 normal) were calculated, and the ratios of T1 to T2 (T1/T2) and of the T1 ratio to the T2 ratio (T1 ratio/T2 ratio) were also analyzed. Diffuse infiltrative marrows revealed prolonged T1 relaxation times in all patients with AML and other severe anemia, and it was not possible to distinguish the two groups of diseases on the basis of T1 values. The T2 relaxation times varied widely in AML, but the mean T2 value of the AML group was not statistically significantly different from that of the anemia group. There were also no significant differences in the T1 ratio, T2 ratio, T1/T2, and the T1 ratio/T2 ratio between leukemic infiltration and hyperplastic hematopoietic marrow. We concluded that measurement of T1 and T2 relaxation times was of limited clinical importance for the histological characterization of diffuse bone marrow disorders.

Adult↗
PubMed1996

[A new three-dimensional CT reconstruction method for cerebral arteriovenous malformation: development and clinical evaluation of see-through view method].

The authors developed a new three-dimensional reconstruction method called "See-Through View (STV)" using a spiral CT in evaluating of cerebral arteriovenous malformation (AVM). Spiral CT was performed in eight patients with AVM. STV was obtained by reconstructing with a voxel transmission projection using a double threshold method. In all eight patients, STV images enable us to depict the nidus of AVM from all angles by see-throughing skull bone, evaluating the relationship of the vascular lesions adjacent to other cerebrovascular or skeletal structures. In conclusion, STV will provide us further spatial recognition, and will be greatly helpful for surgical planning.

Adult↗
PubMed1996

Malignant astrocytomas with homozygous CDKN2/p16 gene deletions have higher Ki-67 proliferation indices.

p16 is involved in a cell-cycle regulatory cascade that includes cyclin-dependent kinase 4 (cdk4), cyclin D1 and pRb. Alterations of each of these components have been described in primary human glioblastoma multiforme (GBM) or GBM cell lines, and alterations of the individual components of this pathway appear inversely correlated with one another. While this suggests that disruption of any individual component has similar oncogenic effects, homozygous deletions of the CDKN2/p16 gene are the most common genetic alteration. We investigated the relationship between homozygous CDKN2/ p16 deletions and cellular proliferation in 50 primary astrocytomas (2 WHO grade I pilocytic astrocytoma, 15 grade II astrocytomas, 20 grade III anaplastic astrocytomas and 13 grade IV GBMs). Using a comparative multiplex PCR assay, homozygous deletions of the CDKN2/p16 gene were detected in 5 anaplastic astrocytomas (25%) and 6 GBMs (46%), but in none of the lower-grade tumors. Ki-67 immunohistochemistry was used to assess the number of proliferating cells in the same samples used for molecular genetic analysis. In both anaplastic astrocytomas and GBMs, Ki-67 proliferation indices were significantly higher in tumors with CDKN2/p16 deletions (20%) than in those without deletions (10%; p = 0.0001). These results suggest that homozygous CDKN2/p16 deletions in high-grade astrocytomas may have a more deleterious effect on cell cycle control than the other aberrations in the p16-cdk4-cyclin D1-pRb pathway, and may provide one explanation for why homozygous CDKN2/p16 deletions are more common genetic events in high-grade astrocytomas than RB mutations or CDK4 amplification.

Adult↗
PubMed1996

Expression of the KAI1 protein in benign prostatic hyperplasia and prostate cancer.

The KAI1 gene, recently identified as a metastatic suppressor gene for prostate cancer, was cloned and was revealed to be identical to the C33/IA4/ R2/4R9 gene. The expression of KAI1 protein was examined immunohistochemically in the tissues from 14 cases of benign prostatic hyperplasia and 46 cases of prostate cancer using mouse monoclonal anti-human C33 antibody. In benign prostatic hyperplasia tissues, KAI1 protein was uniformly expressed in the glandular cell membrane at cell-to-cell borders. The KAI1 protein in the tissues of untreated prostate cancer was also located at similar sites to those of benign prostatic hyperplasia, but the percentage of strongly positive cancer cells was correlated inversely to the Gleason pattern (P < 0.0001, one-way analysis of variance). There was also a statistically inverse correlation between the percentage of KAI1-positive cancer cells and the clinical stage (chi 2 = 9.6; P = 0.0081). In 4 cancer death cases relapsed from endocrine therapy, KAI1 protein was not stained in either primary or metastatic foci. These results indicate that the expression of KAI1 protein correlates to tumor characteristics in prostate cancer.

Adenocarcinoma↗
PubMed1996

Analysis of p53 gene mutations in human glioma cell lines.

Seven human glioma cell lines were examined for mutations of the p53 gene and their mRNA and protein expressions. Five cell lines revealed a missense mutation at, codons 237, 245, or 273. Their p53 mRNA expression was variably distinct and not always comparable to p53 protein expression, suggesting difference in the transcriptional and posttranscriptional regulation. One cell line had a splicing mutation in intron 9 and abnormal splicing was actually demonstrated by RT-PCR analysis. The remaining 1 cell line showed no PCR-amplification of the p53 gene sequence. In an examination of the original tumor tissues, the same mutations were demonstrated in the 5 tumors examined, strongly suggesting that the mutations in the glioma cell lines were derived from their original tumor tissues.

Brain Neoplasms↗