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Biomedical subjects

K Akagi

Publications and source records attributed to K Akagi.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Preoperative scoring and operative complications of unruptured cerebral aneurysms].

Low risk of mortality and morbidity are necessary pre-conditions for surgical treatment of unruptured cerebral aneurysms. We assessed retrospectively 132 patients with angiographically confirmed cerebral aneurysms using an unruptured aneurysm score. Among them, 84 patients were treated surgically. The score consists of the sum of scores for the following factors: associated disease (none: 0, one: 1, two or more: 2); aneurysm size (below 14 mm: 0, 15-24 mm: 1, 25 mm or more: 2); location (anterior circulation: 0, carotid cave: 1, posterior circulation: 2); and multiplicity (single: 0, two or more: 1). Eleven patients had complications and the morbidity rate including asymptomatic lesions was 13.1%. Five patients had permanent neurologic deficits (final morbidity rate 5.9%). The majority of patients with scores less than 1 underwent operations and the morbidity rate was low, whereas patients with scores between 2 and 4 had a higher morbidity rate. Preoperative scoring is useful for predicting surgical risks associated with unruptured cerebral aneurysm.

Adult↗
PubMed1996

Change in ascorbate radical production in an irradiated experimental tumor with increased tumor size.

We have reported that ascorbate radical (Asc.-) could serve as an indicator of the amount of hydroxyl radical and superoxide produced by irradiation in vivo. Using this method, we investigated the relationship between tumor size and Asc.- production after irradiation (10 Gy) and between tumor size and the radical-scavenging ability of WR-2721 (300 mg/kg). Asc.- was measured in normal muscle and SCC-VII tumors transplanted into mice (n = 6). In tumors, the increase in Asc.- significantly decreased with increasing tumor size (r = -0.483; P < 0.05). The increase in Asc.- production after irradiation was more inhibited by WR-2721 in normal muscle tissue than in tumor tissue at various sizes. In tumors, the increase in Asc.- was less inhibited by WR-2721 with increasing tumor size. These results demonstrate that the increase in radical production after irradiation and drug distribution decreased with increasing tumor size and that WR-2721 has excellent differential protection. This method is expected to measure changes in the amounts of local hydroxyl radical and superoxide modified by a change of tumor environment or drug administration.

Amifostine↗
PubMed1996

Analysis of the CDR3 region of the rearranged IgH chain genes in patients with severe combined immunodeficiency and severe lymphopenia.

Human B cell-negative severe combined immunodeficiency (B-SCID) is a primary immunodeficiency disease characterized by both T and B lymphocytopenia and agammaglobulinemia. Although lymphocytes of B-SCID patients express defective recombinase activity and rarely succeed in making Ag receptors, the molecular defect of the human B-SCID remains to be identified. To gain more insight into the human B-SCID defect and its effect on the Ab repertoire, we examined the Ig heavy (H) chain genes of the peripheral blood leaky B cells from three B-SCID patients. Although the number of B cells in their peripheral blood was very limited, we could obtain 41 productive VDJ recombinations from the 58 joints. The recombinations showed a grossly altered pattern characterized by short N nucleotides, short deleted nucleotides from 5' JH segments, immature JH and D segment utilization, absence of VDDJ recombination, and all but one JH segment equal to germline JH segments. Therefore, Ab repertoire of IgH chain gene in human B-SCID was limited because of restricted junctional and combinatorial diversity and few somatic mutations. Furthermore, unusually long P nucleotides were inserted in junctional sequences, which might indicate that resolution of hairpin is impaired in human B-SCID as in the murine SCID.

B-Lymphocytes↗
PubMed1996

Withaferin A: a new radiosensitizer from the Indian medicinal plant Withania somnifera.

Withaferin A, a steroidal lactone isolated from the roots of the Indian medicinal plant Withania somnifera, reduced survival of V79 cells in a dose-dependent manner. LD50 for survival was 16 microM. One-hour treatment with a non-toxic dose of 2.1 microM before irradiation significantly enhanced cell killing, giving a sensitizer enhancement ratio (SER) of 1.5 for 37% survival and 1.4 for 10% survival. SER increased with drug dose, but at higher doses the increased lethality appears to be due to two effects-- drug toxicity and radiosensitization. The drug induced a G2/M block, with a maximum accumulation of cells in G2-M phase at 4 h after treatment with 10.5 microM withaferin A in 1 h. The applicability of this drug as a radiosensitizer in cancer therapy needs to be explored.

Animals↗
PubMed1996

Measurement of intratumor pH by pH indicator used in 19F-magnetic resonance spectroscopy. Measurement of extracellular pH decrease caused by hyperthermia combined with hydralazine.

RATIONALE AND OBJECTIVES: Without affect of metabolic changes, the authors measured intratumor pH by using 19F-magnetic resonance spectroscopy (MRS) with a fluorine compound (ZK-150471) on the basis of a calibration curve by pH electrode. METHODS: Using the 4.7-tesla magnetic resonance apparatus, a fluorine compound that had acid-base equilibrial change and was impermeable within cell membranes was used. The fluorine compound was injected intravenously. The signal was obtained from mouse mammary cancer by creating an experimental tumor on the leg of mice. And the tumors, which were heated with and without hydralazine. The pH evaluated from chemical shift of the fluorine compound. The pH data was obtained from an electrode for reference. RESULTS: The pH of nontreated tumors (n = 25) were 6.94 + 0.091. The pH decreased to 6.772 + 0.169 at 20 minutes even after 20 minutes of heating, and decreased to < 6.71 at 40 minutes after every heating time. The pH decreased to 6.456 at 20 minutes after 15 minutes of heating combined with hydralazine, and to 6.416 at 40 minutes after same treatment. CONCLUSIONS: It is possible to measure the extracellular pH by 19F-MRS with the fluorine compound noninvasively in vivo, even after heating.

Animals↗
PubMed1996

Lack of chemoprevention effects of the monoterpene d-limonene in a rat multi-organ carcinogenesis model.

Modifying effects of dietary administration of the monoterpene d-limonene were examined using a multi-organ carcinogenesis model. Groups of twenty F344 male rats were treated sequentially with N-diethylnitrosamine (DEN, i.p.), N-methyl-N-nitrosourea (MNU, i.p.), 1,2-dimethylhydrazine (DMH, s.c.), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN, in drinking water) and dihydroxy-di-N-propylnitrosamine (DHPN, in drinking water) during the first 4 weeks (DMBDD treatment), and then d-limonene was administered in the diet, at the dose of 2.0, 1.0 or 0.5%. The maximal tolerable dose was 2.0% under the present conditions. Further groups were treated with DMBDD or 2.0% d-limonene alone as controls. All surviving animals were killed at week 28, and major organs were examined histopathologically for development of preneoplastic and neoplastic lesions. The incidences and/or multiplicities of renal atypical tubules and adenomas were increased in animals fed 2.0% d-limonene. The immunohistochemical reactivity for alpha2u-globulin in the proximal tubules was greater in rats fed d-limonene than in the carcinogen alone group. No enhancing or inhibitory effect was noted for tumor development in other organs. The present results indicate a lack of any chemopreventive effect of d-limonene in any organ of male rats under the present experimental conditions.

1,2-Dimethylhydrazine↗
PubMed1996

Gastrin-releasing peptide-like immunoreactivity is present in human maternal and fetal placental membranes.

Extracts of human term amnion, placenta, and chorion/decidual tissue (n = 5) contained gastrin-releasing peptide-like immunoreactivity (GRPLI) in amounts of 4.7 +/- 2.9 (pmol/g wet wt; mean +/- SEM), 3.6 +/- 1.1 and 2.9 +/- 1.5, respectively. Using C-terminally directed antisera and gel filtration chromatography and reverse-phase high-performance liquid chromatography (HPLC), each tissue contained molecular forms consistent with the presence of GRP1-27 and GRP18-27 but also contained larger amounts of two GRPLI peaks, which apparently are novel GRP-like peptides. In contrast, tissue extracts of human fetal lung contained only GRP1-27, GRP14-27, and GRP18-27. Using RT-PCR and specific GRP primers and probes, messenger RNA encoding for GRP was readily demonstrable from 6-weeks gestation throughout pregnancy to term in full-thickness membranes, placental villi, and decidua. Positive immunohistochemical staining for GRP occurred in extravillous trophoblasts in decidual septa and fetal membranes, cytotrophoblasts, syncytiotrophoblast, and certain stromal cells in placental villi and amniotic epithelium. GRPLI and GRP messenger RNA were present from the earliest dates examined (6-9 weeks) throughout pregnancy to term. Given the proven trophic nature of GRP and related peptides, these peptides may play important roles in maternal, placental, and fetal development during human pregnancy.

Amnion↗
PubMed1996

A family of multiple endocrine neoplasia type 2A: genetic analysis and clinical features.

Since a heterozygous missense mutation of the RET proto-oncogene in the germline was found to cause multiple endocrine neoplasia type 2A (MEN 2A) in 1993, some 20 different mutations of this gene have been identified in MEN 2A kindreds. We report an MEN 2A family in which serine (AGC) substitutes for cysteine (TGC) at codon 618 in exon 10 of the RET proto-oncogene. The mutation was identified by sequencing PCR products of exons 10 and 11 in the proband. Since this mutation results in creation of a new cleavage site for Alu I restriction enzyme, most of the other members of the family were screened by digestion of the PCR product of exon 10 with this enzyme. Eleven of 20 subjects across four generations examined have the mutation of the RET proto-oncogene, and all of the adult gene carriers except one woman had MTC. Characteristics of this family are 1) pheochromocytoma has been found in only the proband, 2) no obvious hyperparathyroidism has been observed, and 3) the prognosis is favorable, with nobody dying of MEN 2A itself. Genetic analysis of MEN 2A is definitely useful and essential for screening of a MEN 2A family. It is very important to accumulate cases with MEN 2A and investigate the phenotype and the prognosis in each mutation.

Adult↗
PubMed1996

Primary adult T cell leukemia of bone: two patients with primary bone lesion showing monoclonal integration of HTLV-I proviral DNA.

Adult T cell leukemia (ATL), a neoplasm of mature helper T lymphocytes is etiologically associated with human T lymphotropic virus type-I (HTLV-I). ATL cells infiltrate various organs, the lung, skin, central nervous system, gastrointestinal tract, and bone, causing various clinical manifestations. Two unusual cases of ATL, in which lytic bone lesion was the primary site of ATL, are described. One patient had multiple lytic lesions in bones without any involvement of other organs, and the other patient had a bone lesion in the right radius, which disappeared after chemotherapy. In both cases, monoclonal integration of HTLV-I provirus was demonstrated in the genomic DNA from each bone lesion. Although their clinical courses and pathological findings were different, ATL in both patients began as a bone lesion, showing that primary lymphoma of bone can be manifested in ATL cases.

Adult↗
PubMed1996

Detection of an ascorbate radical in an irradiated mice using electron spin resonance (ESR).

Ascorbate radical (Asc.-) produced by the reaction of AscH- (ascorbic acid) with HO or O2.- after irradiation in mice has been measured. It is possible to measure Asc.- easily using ESR and a dialysis method in which Asc.- is collected at room temperature in the interstitial fluid through the dialysis membrane. After irradiation, Asc.- increases in both normal muscle and tumor tissues (SCC-VII) in proportion to the radiation dose. These results suggest that the amount of HO and O2.- produced is reflected in the Asc.- production. This method has been found more useful for the following reasons, (i) no special treatment, such as freezing of the sample, and no administration of noxious agents are necessary to measure Asc.-, (ii) irradiation using a dose of only a few Gy shows an increase in production of Asc.-, and (iii) this method dose not require removal of organs. Using this method, Asc.- can serve as an indicator of the amount of HO and O2.- produced by irradiation in vivo.

Animals↗
PubMed1995

The 3' enhancer region determines the B/T specificity and pro-B/pre-B specificity of immunoglobulin V kappa-J kappa joining.

Using transgenic substrates, we found that the immunoglobulin kappa gene 3' enhancer (E3') acts as a negative regulator in V kappa-J kappa joining. Although the E3' was originally identified as a transcriptional enhancer, it acts in a suppressive manner for recombinational regulation. Base substitution analysis has shown that the PU.1-binding site within the E3' regulates the B/T specificity of V kappa-J kappa joining. In a substrate with a mutated PU.1-binding site (GAGGAA to TCTTCG), V kappa-J kappa joining occurred not only in B cells, but also in T cells. The E3' region is also responsible for determining the pro-B/pre-B specificity of V kappa-J kappa joining. When the E3' region was deleted, kappa gene rearrangement actively occurred at the early pro-B stage of B cell development: nongermline (N) nucleotides were common at recombination junctions.

Animals↗
PubMed1995

Modulating effects of ellagic acid, vanillin and quercetin in a rat medium term multi-organ carcinogenesis model.

Effects of dietary supplementation with the antioxidants ellagic acid, quercetin and vanillin were examined using a medium term multi-organ carcinogenesis model in rats. Groups of 10-15 male F344 rats were given i.p. injections of diethylnitrosamine (DEN, 100 mg/kg body wt.) and N-methylnitrosourea (MNU, 20 mg/kg body wt), s.c. injections of 1,2-dimethylhydrazine (DMH, 40 mg/kg body wt.), together with 0.05% N-butyl-N-(4- hydroxybutyl)nitrosamine (BBN) and 0.1% 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN), both in the drinking water, for a total multiple initiation period of 4 weeks (DMBDD) treatment). Ellagic acid, quercetin or vanillin, each at a dose of 1% each in the diet were administered from 1 day before and throughout the carcinogen exposure period, or after completion of the initiation regimen. All surviving animals were sacrificed at the end of week 36, and major organs were examined histopathologically. In the small intestine, significant reductions in the incidence and number of tumors (adenomas and carcinomas) were observed in the groups administered ellagic acid during (8%, 0.08 +/- 0.29) or after (8%, 0.08 +/- 0.29) DMBDD treatment, and those receiving quercetin after DMBDD treatment (0%) compared to the control value (57%, 1.07 +/- 1.21). Although the incidences were not statistically significant, slightly decreased numbers of small intestinal tumors were found in the groups receiving vanillin during (0.33 +/- 0.72), or after (0.40 +/- 0.83) DMBDD treatment. The incidence of large intestinal carcinomas in the group treated with vanillin during DMBDD treatment was significantly higher (73%) than the control value (21%). These results indicated that while ellagic acid and quercetin exerted potent chemopreventive action in both the initiation and promotion stages in the present experimental system, their beneficial effects were restricted to the small intestine. Since small intestinal carcinomas are very infrequent in humans, the advantages of these phenolic compounds for human application as chemopreventors should not be overestimated.

1,2-Dimethylhydrazine↗