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Biomedical subjects

Y Kojima

Publications and source records attributed to Y Kojima.

At least 181 records · Page 10Linked to original sources
PubMed1997

Trends of survival in neuroblastoma and independent risk factors for survival at a single institution.

To assess the progress of survival in neuroblastoma which varies with many risk factors and to evaluate the influence of these factors on survival as independent risk factors. The study subjects were 159 neuroblastoma patients seen from 1965-1994 at the oldest and largest children's hospital in Japan. Trends of survival in three treatment eras-1965-81, 1982-86, 1987-94-were assessed by the Kaplan-Meier method for different sex, age at diagnosis, the clinical stage, the site of onset, and the histological type. Then the influence on survival of these factors as independent prognostic variables was evaluated by the Cox proportional hazards regression analysis. Age at diagnosis, the clinical stage, the site of onset, the histological type, and the treatment era were independent risk factors in the order of their influence on survival. Unfavorable survival outcomes were obtained for patients with age at diagnosis above 1 year, the clinical stage of VI by the Evans classification, adrenal onset, and neuroblastoma rather than ganglioneuroblastoma. Survival improved from the first to the second and from the second to the third treatment era. Improvement of survival in neuroblastoma took place during the past 3 decades. Age at diagnosis, the clinical stage, and the histological type have still remained overwhelming prognostic factors over the progress in treatment.

Adrenal Gland Neoplasms↗
PubMed1997

Differential role of metallothionein on Zn, Cd and Cu accumulation in hepatic cytosol of rats.

To examine the role of metallothionein (MT) on heavy metal accumulation in hepatic cytosol of rats, this study was carried out to determine the relative Zn, Cd and Cu-binding capacities of MT in hepatic cytosol of Zn, Cd and Cu-injected rats, respectively. The heavy metal contents were detected in the liver and cytosol in the following proportions: 65.2-74.8% of the Zn content, 61.9-65.6% of the Cu content, and approx. 65% of the Cd content. Each rat was given a single intraperitoneal injection of saline, ZnSO4 (1, 5, 10 and 20 mg Zn/kg b.w.), CuSO4 (2, 4 and 6 mg Cu/kg b.w.) or CdCl2 (1, 2 and 3 mg Cd/kg b.w.). The amounts of the increased Zn and Cu were attributable to MT and high molecular weight proteins, while most of the increased Cd was attributable to MT. There was a close relationship between heavy metal content of the cytosol and MT in all heavy metal-injected rats. Our data demonstrated that approx. 60% of the increased Zn or Cu in the hepatic cytosol of Zn or Cu-injected rats was bound to MT, while 83% of the increased Cd in hepatic cytosol of Cd-injected rats was bound to MT. Therefore the order of relative binding capacity in vivo of MT determined for several metals (Cd > Zn > Cu) did not correlate with the published in vitro order of affinity to MT, Cu > Cd > Zn. These results suggested that the role of MT in Zn or Cu accumulation in the liver of Zn or Cu-injected rats was different from that of MT in Cd accumulation in the liver of Cd-injected rats.

Animals↗
PubMed1997

Effects of amino acid replacements on cadmium binding of metallothionein alpha-fragment.

To evaluate whether only 20 cysteine residues at invariant positions are needed to bind and coordinate the metals in metallothioneins (MTs), and whether changing the positions of cysteine residues in the sequence affects the metal-binding capacity and the coordination of MTs, we examined the cadmium-binding affinities of seven mutant MT alpha s using an Escherichia coli expression system. Five mutant MT alpha s in which the constitutive amino acid residues other than cysteines of the alpha-fragment were replaced with glycine residues, and the remaining two mutant MT alpha s in which the invariant positions of the cysteine residues of the alpha-fragment were shifted, were analysed for their ability to be expressed as cadmium-binding forms and for their biochemical properties. The results showed that extreme alteration of the constitutive amino acid residues other than cysteines in the MT alpha-fragment leads to disruption of their cadmium-binding abilities and of their structure. However, mutant MT alpha s containing changes of the invariant positions of the cysteine residues were expressed in a cadmium-binding form in Escherichia coli, although the invariant positions of 20 cysteine residues in the MTs are thought to be important for their metal-binding abilities. These results suggest that the position of cysteine residues and the chemical nature of the other amino acids in the amino acid sequence of MTs are less critical than expected.

Amino Acid Sequence↗
PubMed1997

Pharmacokinetic analysis of benzodiazepine receptor binding of [123I]iomazenil in human brain.

PURPOSE: The purpose of this study is to evaluate the central benzodiazepine (BZP) receptor binding of iomazenil (IMZ) by pharmacokinetic analysis and to establish a methodology for the diagnosis of CNS disorders with abnormalities in BZP receptor binding. METHODS: BZP receptor binding of IMZ was analyzed kinetically using plasma concentration-time profiles and dynamic single photon emission computed tomography (SPECT) data obtained after the intravenous administration of IMZ to patients with neuropsychiatric disease. The analysis was based on a 3-compartmental model including the processes of both blood-brain barrier (BBB) transport and BZP receptor binding. RESULTS: Hydrolized metabolite of IMZ was detected in plasma, indicating the need for separation by HPLC. The BBB influx clearance and the receptor binding potential of IMZ in the medial temporal region was reduced in the epileptic patient. CONCLUSIONS: Our findings suggest the possibility of detecting the epileptic focus by using our method.

Blood-Brain Barrier↗
PubMed1997

Hepatic injury localized to the field of total lymphoid irradiation.

A 37-year-old woman with severe aplastic anemia underwent allogeneic bone marrow transplantation following cyclophosphamide (CY) and total lymphoid irradiation (TLI). On day +30, a CT scan was carried out because of a mild elevation in liver enzymes, and it revealed a low density area with a sharp border in the left lobe corresponding to the irradiated area. MRI showed a hypersignal intensity on both T1 and T2-weighted images and suggested that hepatic damage was mainly severe fatty change. These abnormalities resolved with no treatment. CY with TLI for adult patients with severe aplastic anemia may induce hepatic injury.

Adult↗
PubMed1997

Restriction of cadmium transfer to eggs from laying hens exposed to cadmium.

The transfer of Cd to eggs of white Leghorn laying hens has been shown to be restricted. After Cd was injected ip into laying hens, the Cd concentrations in the blood, livers, ovaries, and eggs were measured. Although the Cd concentrations in the maternal blood and livers increased remarkably at certain levels of administrations, the Cd concentration in the yolks of eggs was not significantly increased, and was less than 0.04 microgram/g wet weight. After egg production stopped in the highest injected group (7.5 mg Cd/kg), Cd in the yolks of eggs had an accumulated range of 0.02-0.03 microgram/g wet weight. This was despite the high Cd accumulation in the liver. Furthermore, the Cd concentration in the follicle walls of the ovary increased and was 13- to 52-fold higher than in the follicle yolks. An additional experiment was conducted in order to estimate whether hatching success is affected by the Cd in the laid eggs of Cd-injected laying hens. The ratio of hatching success in the 0.3 or 1.2 micrograms Cd/egg-injected groups was similar to that in the saline-injected group, indicating that a small amount of Cd in the eggs might exert no marked influence on the hatching success. In conclusion, Cd transfer from laying hen to eggs was restricted after the maternal bird was exposed to Cd. Furthermore, Cd accumulates in the follicle walls of ovary. These results suggest that the follicle walls might play a role in protecting the follicle yolks against Cd toxicity.

Animals↗
PubMed1997

A mutant metallothionein which has inverse fragment composition exhibits high cadmium-binding ability.

In order to investigate the role of the alpha-fragment of metallothionein (MT) in metal-binding, two mutant MTs, beta Ala alpha Cys- and alpha Cys beta Cys-mutant MTs, expressed in Escherichia coli were analyzed for their metal-binding ability. A mutant MT where all of the cysteine residues in the beta-fragment of MT were substituted by alanine residues and another mutant MT that had the inverse fragment composition (alpha-beta, i.e., beta-alpha in wild-type MT) were designated as the beta Ala alpha Cys and the alpha Cys beta Cys-mutant MT's, respectively. Both expressed Cd-binding mutant MTs were identified by amino acid analyses. From their metal-binding capacities, the two mutant MTs exhibited higher Cd-binding abilities than wild-type MT. The results suggested that the alpha-fragment plays a key role in the Cd-binding of MT, and that the metal-binding tightness of MT is dependent on the metal-binding ability of a prior fragment in MT.

Alanine↗
PubMed1997

Significance of alpha-fragment of metallothionein in cadmium binding.

In order to evaluate the significance of alpha- and beta-fragments of metallothionein with regard to Cd binding in biosynthetic processes, the Cd-binding ability of four mutant metallothioneins was examined using the Escherichia coli expression system. The features of the mutant metallothioneins were proteins in which cysteine residues in the alpha- or beta-fragment were replaced with alanine residues, or that the sequential order of the fragments was altered. The expressed mutant metallothioneins having an intact alpha-fragment showed the constructive abilities of the Cd-thiolate cluster. On the other hand, mutant metallothionein having an alpha-fragment lacking metal-binding sites exhibited no Cd-binding ability. The condition for maintaining the Cd-binding capability of metallothionein was that the alpha-fragment remains intact irrespective of the sequential order of the two fragments. The alpha-fragment is an indispensable component in metal-binding processes of Cd-metallothionein.

Amino Acid Sequence↗
PubMed1997

Cessation of spermatogenesis in juvenile spermatogonial depletion (jsd/jsd) mice.

BACKGROUND: Mice homozygous for the jsd (juvenile spermatogonial depletion) allele are sterile because they become azoospermic. The onset of such azoospermia was investigated by histologic analysis of sections of testes from jsd/jsd mice. METHOD: The testes removed from C57BL/6-jsd/jsd mice aged 3 to 10 weeks were examined microscopically. RESULTS: At 3 weeks of age, spermatocytes were seen in most of the seminiferous tubules of jsd/jsd mice. However, the number of tubules that contained spermatids was significantly smaller than that counted in the wild-type mice. Since degenerative figures were not abundant in the jsd/jsd testes, the decreased number of spermatids found in the tubules suggested a longer duration of development from spermatocyte to spermatid in jsd/jsd mice. The abnormality extended to the development of type B spermatogonia, and a decrease in their number became apparent after 6 weeks of age in most of the jsd/jsd tubules. However, as early as 3 weeks of age, a few seminiferous tubules in jsd/jsd mice already contained only Sertoli cells and type A spermatogonia. CONCLUSION: It is assumed that the decrease in type B spermatogonia occurred at various ages and locations. The defect of spermatogenesis in jsd/jsd mice was attributable to aberrations in multiple steps of spermatogenesis.

Aging↗
PubMed1997

Transurethral visual laser ablation of the prostate for benign prostatic hyperplasia using a KTP/YAG laser.

BACKGROUND: Transurethral visual laser ablation of the prostate (VLAP) has been established as an alternative method for the treatment of benign prostatic hyperplasia (BPH). However, most VLAP procedures utilize only a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. Since a potassium-titenyl-phosphate (KTP) laser offers limited tissue penetration, KTP can be safely utilized to excise part of the obstructing prostatic tissue. This study assessed the interaction between KTP vaporization and YAG coagulative ablation to determine the safety and efficacy of VLAP utilizing a combined KTP/YAG treatment. METHODS: Forty patients with bladder outlet obstruction secondary to BPH were treated with VLAP using a KTP/YAG laser. The laser light was delivered by an angle delivery device. RESULTS: Most cases demonstrated a significant improvement in routine subjective and objective parameters (AUA symptom score, peak flow rate, average flow rate, and amount of residual urine). No significant complications relating to this procedure were reported, however, 4 patients experienced postoperative acute urinary retention. CONCLUSION: KTP/YAG laser ablation of the prostate is safe and effective for the treatment of BPH.

Aged↗
PubMed1997

Secondary acute monocytic leukemia occurring during the treatment of a testicular germ cell tumor. A case report and review of the literature.

Secondary leukemia following chemotherapy or radiotherapy for mediastinal germ cell tumors is a well-described entity. It also may occur in patients with testicular germ cell tumors. We report a case of acute monocytic leukemia occurring in a 44-year-old man who received etoposide-based chemotherapy and radiotherapy for a recurrent, metastatic testicular germ cell tumor. The patient received 14 cycles of systemic chemotherapy for pulmonary and para-aortic lymph node metastases following his initial orchiectomy. The total amount of etoposide this patient received was 6,400 mg/m2. Leukemia occurred 11 years after orchiectomy. A literature review revealed 25 other reported cases of secondary leukemias after treatment for testicular carcinoma. It is not clear whether chemotherapy, radiotherapy or both are responsible for the secondary leukemias seen in these patients.

Adult↗
PubMed1997

Renal pelvic cancer with tumor thrombus in the vena cava inferior. A case report and review of the literature.

Renal pelvic cancer with a large vein tumor thrombus is very rare. We report a case of transitional cell carcinoma of the right renal pelvis with tumor thrombus in the inferior vena cava. Based on the radiological findings, the patient was diagnosed having renal cell carcinoma with tumor thrombus in the vena cava preoperatively. Radical nephrectomy with thrombectomy was performed. A literature review of 17 reported cases revealed that 13 cases (76.5%) were diagnosed as renal cancer preoperatively. Prognosis of transitional cell carcinoma with vena cava tumor thrombus is relatively poor compared to that of renal cell carcinoma with a large vein tumor thrombus.

Carcinoma, Renal Cell↗
PubMed1997

Antitumor effect of CPT-11, a camptothecin derivative, on human testicular tumor xenografts in nude mice.

OBJECTIVE: The antitumor effect of CPT-11, a camptothecin derivative, on two human testicular embryonal carcinomas (TTSC-2 and TTSC-3) heterotransplanted into-nude mice was studied. MATERIALS AND METHODS: Tumor-bearing nude mice were given daily intraperitoneal injections of the anticancer drugs in 0.1 ml saline 3 times at 3-day intervals. At the end of the experiments tumors were resected and subjected to light-microscopic observation. RESULTS: When 10, 30 and 50 mg/kg of CPT-11 was administered to tumor-bearing mice intraperitoneally, the antitumor effect of CPT-11 was observed dose-dependently in both TTSC-2 and TTSC-3. When 30 mg/kg of CPT-11 was administered in combination with CDDP, complete tumor regression was observed in both TTSC-2 and TTSC-3 tumors. Histological findings correlated well with the decrease in tumor volume of treated tumors. No mice died after treatment with CPT-11 in a single-agent and combination chemotherapy. CONCLUSION: Chemotherapy with CPT-11 was an effective and safe method against human testicular tumors heterotransplanted in nude mice.

Animals↗
PubMed1997

A beta-glucosidase gene downstream of the cellulose synthase operon in cellulose-producing Acetobacter.

An open reading frame was found 214 bp downstream of the cellulose synthase operon of Acetobacter. The encoded amino acid sequence was found to be similar to some beta-glucosidases (G3ases). We detected G3ase activity in the culture medium and analysis of the N-terminal amino acid sequence showed that this gene encodes the enzyme. Therefore, it is possible that this region is a gene cluster for cellulose synthesis.

Acetobacter↗
PubMed1997

Altered imprinting of the H19 and insulin-like growth factor II genes in testicular tumors.

PURPOSE: H19 and insulin-like growth factor II (IGF2) genes are imprinted in normal human tissues. Recent reports have described loss of imprinting (LOI) for these genes in some malignancies. We therefore examined the allele-specific expression of the H19 and IGF2 genes in testicular tumors. MATERIALS AND METHODS: Restriction fragment length polymorphisms were examined in 17 testicular germ cell tumors and 2 testicular malignant lymphomas. RESULTS: All 4 informative testicular germ cell tumors showed LOI for the H19 gene. Five of 9 informative germ cell tumors showed LOI for the IGF2 gene, while testicular lymphomas did not show biallelic expression of the H19 or IGF2 gene. CONCLUSION: Loss of imprinting for the H19 and IGF2 genes in testicular seminomatous germ cell tumors may be involved in oncogenesis.

Genes, Tumor Suppressor↗
PubMed1997

[The correlation between interleukin-10 and interferon-gamma produced by peripheral blood mononuclear cells stimulated by house dust mite antigen in atopic dermatitis].

The production of interleukin (IL)-10 and interferon (IFN)-gamma by peripheral blood mononuclear cells (PBMC) stimulated by house dust mite (HDM)antigen and concanavaln A (Con A) was measured in patients with atopic dermatitis (AD). The HDM-stimulated PBMC from AD patients revealed to produce significantly higher levels of IL-10 (12 h: 918.4 +/- 206.5, 24 h: 1252.5 +/- 145.8, 72 h: 1332.7 +/- 123.9 pg/ml) than those from normal control subjects (12 h: 231.1 +/- 139.0, 24 h: 585.7 +/- 196.2, 72 h: 813.5 +/- 181.8 pg/ml). Con A-stimulated AD-PBMC also showed significantly higher levels of IL-10 production than those from normal controls, although they were lower than the productions induced by HDM antigen. By contrast, the levels of IFN-gamma from AD PBMC stimulated with HDM or Con A, were significantly lower than those from normal controls. IFN-gamm production might be down-regulated by IL-10 in AD-PBMC. The overproduction of IL-10 seems to show that helper T type 2 (Th2) cells are rather dominantly activated than Th1 cells and Th2 cells might contribute to produce the cytokines in response to HDM antigen in AD patients.

Adult↗