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M Yoshimoto

Publications and source records attributed to M Yoshimoto.

At least 73 records · Page 4Linked to original sources
PubMed2000

Hypoxic but not ischemic neurotoxicity of free radicals revealed by dynamic changes in glucose metabolism of fresh rat brain slices on positron autoradiography.

Dynamic changes in the regional cerebral glucose metabolic rate induced by hypoxia/reoxygenation or ischemia/reperfusion were investigated with a positron autoradiography technique. Fresh rat brain slices were incubated with [18F]2-fluoro-2-deoxy-D-glucose ([18F]FDG) in oxygenated Krebs-Ringer solution at 36 degrees C, and serial two-dimensional time-resolved images of [18F]FDG uptake in the slices were obtained. In the case of loading hypoxia (oxygen deprivation)/pseudoischemia (oxygen and glucose deprivation) for various periods of time, the net influx constant (K) of [18F]FDG at preloading and after reoxygenation/pseudoreperfusion (post-loading) was quantitatively evaluated by applying the Patlak graphical method to the image data. Regardless of the brain region, with hypoxia lasting > or =20 minutes, the postloading K value was decreased compared with the unloaded control, whereas with pseudoischemia of < or =40 minutes, approximately the same level as the unloaded control was maintained. Next, the neuroprotective effect against hypoxia/pseudoischemia loading induced by the addition of a free radical scavenger or an N-methyl-D-aspartate (NMDA) antagonist was assessed by determining whether a decrease in the postloading K value was prevented. Whereas with 20-minute hypoxia, both agents exhibited a neuroprotective effect, in the case of 50-minute pseudoischemia, only the NMDA antagonist did so, with the free radical scavenger being ineffective. These results demonstrate that hypoxia causes irreversible neuronal damage within a shorter period than ischemia, with both free radicals and glutamate suggested to be involved in tandem in the neurotoxicity induced by hypoxia, whereas glutamate alone is involved in ischemic neurotoxicity.

Animals↗
PubMed2000

Overexpression of midkine in pancreatic duct adenocarcinomas induced by N-Nitrosobis(2-oxopropyl)amine in hamsters and their cell lines.

The expression of midkine (MK) was investigated in pancreatic ductal hyperplasias, atypical hyperplasias and adenocarcinomas induced by N-nitrosobis(2-oxopropyl)amine (BOP) in hamsters, and in hamster ductal adenocarcinoma cell lines (HPD-1NR, -2NR and -3NR). MK mRNA was clearly overexpressed in invasive pancreatic duct adenocarcinomas (PCs) and the three cell lines as assessed by northern blot analysis, and MK protein expression increased from ductal hyperplasia through atypical hyperplasias, intraductal carcinomas and invasive PCs by immunohistochemistry. The extent of overexpression of MK mRNA in PCs was almost the same as in hamster whole embryonic tissue. MK is reported to be a retinoid-responsive gene, but MK mRNA expression was not affected by treatment with all-trans retinoic acid (tRA) or N-(4-hydroxyphenyl)retinamide (4-HPR) in HPD-1NR cells. The results thus suggest that MK expression is involved in the development and progression of pancreatic ductal adenocarcinomas induced by BOP in hamsters, with loss of upregulation by retinoic acid.

Animals↗
PubMed2000

Fiber connections of the corpus mamillare in a percomorph teleost, tilapia Oreochromis niloticus.

The hypothalamus and perhaps its function appear to be similar among vertebrates. Thus, studying the teleostean hypothalamus could be a good model for understanding common neural circuits and mechanisms retained through the vertebrates. However, connections of the inferior lobe, which is considered the hypothalamus in teleosts, is poorly known. The corpus mamillare (CM) is a nucleus of the inferior lobe named after the mammalian mamillary body based on similarities in external morphology. Afferent connections of the CM have been reported only in cypriniform teleosts. These include projections from the nucleus pretectalis superficialis pars magnocellularis, a nucleus lacking in percomorph teleosts, and projections from the secondary gustatory nucleus. Efferent connections of the CM have not been reported in teleosts. In the present study, the CM and its subdivisions and the connections of these subnuclei were identified in isolated and maintained brains of tilapia Oreochromis niloticus by local DiI and biocytin injection. Afferent connections confirmed by reciprocal injections were from the nucleus diffusus lobi inferioris (NDLI) and the nucleus diffusus tori lateralis (NDTL). Efferent connections of each CM subnuclei were also reciprocally confirmed. These connections were to the area dorsalis pars medialis of the telencephalon, the nucleus ventromedialis (NVM) of the thalamus, the tectum opticum (TO), and the nucleus posterioris periventricularis. Because the NDLI is known to receive gustatory information in tilapia, the CM could relay gustatory inputs to multisensory areas, the TO and NVM, for which there are no current reports regarding gustatory inputs.

Afferent Pathways↗
PubMed2000

Short stature homeobox-containing gene duplication on the der(X) chromosome in a female with 45,X/46,X, der(X), gonadal dysgenesis, and tall stature.

We report on a Japanese female with 45,X[40]/46,X, der(X)[60], primary amenorrhea, and tall stature. She was confirmed to have complete gonadal dysgenesis at 19 yr of age and was placed on hormone replacement therapy. Growth assessment revealed that she had a low normal height until her early teens, but continued to grow with a nearly constant height velocity in her late teens, attaining a final height of 172 cm (+ 2.9 SD), which surpassed her target height range. Fluorescence in situ hybridization analysis for 10 loci/regions on the X-chromosome together with the whole X-chromosome and the Xp-specific and Xq-specific paintings showed that the der(X) chromosome was associated with duplication of roughly distal half of Xp, including SHOX (short stature homeobox-containing gene), and deletion of most of Xq. Microsatellite analysis for eight loci at Xp22 and nine loci at Xq26-28 indicated that the normal X-chromosome was of maternal origin, and the der(X) chromosome was of paternal origin. The results, in conjunction with the adult height data in 47,XXX, 46,XX gonadal dysgenesis, 47,XXY, 46,XY gonadal dysgenesis, and 46,X, idic(Xq-), suggest that the tall stature of this female is caused by the combined effects of SHOX duplication on the der(X) chromosome and gonadal estrogen deficiency. Furthermore, the similarity in the growth pattern between this female and patients with estrogen resistance or aromatase deficiency implies that the association of an extra copy of SHOX with gonadal estrogen deficiency may represent the further clinical entity for tall stature resulting from continued growth in late teens or into adulthood.

Adult↗
PubMed2000

Antimutagenicity of the purple pigment, hordeumin, from uncooked barley bran-fermented broth.

The novel purple pigment hordeumin, an anthocyanin-tannin pigment, was produced from barley bran-fermented broth. The mutagenicity or antimutagenicity of hordeumin was investigated according to the Ames method, an indication of the safety of food, using Salmonella typhimurium TA98. Despite the presence of S-9 mix, hordeumin was not mutagenic. On the other hand, hordeumin effectively decreased a reverse mutation from Trp-P-1, Trp-P-2, IQ, and B[a]P. Furthermore, hordeumin also decreased the reverse mutation from dimethyl sulfoxide extracts of grilled beef.

Anthocyanins↗
PubMed2000

Synphilin-1 is present in Lewy bodies in Parkinson's disease.

Alpha-synuclein is believed to play an important role in Parkinson's disease (PD). Mutations in the alpha-synuclein gene are responsible for familial forms of PD and alpha-synuclein protein is a major component of Lewy bodies in patients with sporadic PD. Synphilin-1 is a novel protein that we have previously found to associate in vivo with alpha-synuclein. We now show that synphilin-1 is present in Lewy bodies of patients with PD. Our data suggest that synphilin-1 could play a role in Lewy body formation and the pathogenesis of PD.

Aged↗
PubMed2000

[Intramedullary spinal cord metastasis associated with hemorrhage: a case report].

A rare case of intramedullary spinal cord metastasis associated with hemorrhage was reported. A 74-year-old man had a subacute onset of paraparesis. He became almost paraplegic within a few days. MRI revealed an intramedullary spinal lesion in the epiconus at the Th 11 and Th 12 level, but spinal angiography did not show any abnormality. Since repeated MRI showed enlargement of the lesion, surgery was performed under the diagnosis of an intramedullary spinal cord tumor. Under general anesthesia, a midline myelotomy of about 3 cm was performed and a grayish, elastic and circumscribed tumor as well as a liquefied hematoma in the caudal part was observed. Both the tumor and the hematoma were removed almost totally. The patient's paraparesis improved slightly after surgery. The histological diagnosis was adenocarcinoma. The primary source was unknown, but multiple small metastatic tumors were found in the lung, liver and brain, etc. Hemorrhage from intramedullary spinal cord metastasis is extremely rare with only 6 reported cases in the recent literature. Rapid deterioration of symptoms caused by the hematoma may make the diagnosis more difficult. Indication of surgical treatment should be carefully determined because prognosis of intramedullary spinal cord metastasis is generally very poor.

Adenocarcinoma↗
PubMed2000

Allelic loss at 1p34-36 predicts poor prognosis in node-negative breast cancer.

Allelic losses of specific chromosomal regions in the DNA of tumor cells, which imply loss of tumor suppressor genes normally resident at those loci, may become useful postoperative prognostic indicators for breast cancers that have not yet metastasized to lymph nodes. To examine whether specific allelic losses might correlate with postoperative disease-free survival, we tested tumors from a cohort of 228 node-negative breast cancer patients for allelic losses at 18 microsatellite loci chosen to represent either a known tumor suppressor gene or a region where genetic alterations are frequent in breast tumors. We followed the patients clinically for 5 years or until death (if patient death occurred before completion of 5 years of follow-up). Patients whose tumors had lost an allele at 1p34-36 bore significantly higher risks of postoperative recurrence than those whose tumors retained both alleles of the markers in that region [the 5-year recurrence rate was 15% among patients with losses versus 2% among patients with retention (P = 0.001)]. Multivariate analysis demonstrated that allelic loss at 1p34-36 was an independent postoperative predictor of shorter disease-free survival (hazard ratio, 5.8; P = 0.0117). Thus, allelic losses at 1p34-36 in a tumor might have a potential to serve as a negative prognostic indicator to guide postoperative management of breast cancer patients, especially in the selection of high-risk women who will benefit from adjuvant chemotherapy and endocrine therapy.

Adult↗
PubMed2000

[Day surgery for breast cancer].

In Japan, day surgery for breast cancer usually means partial mastectomy without axillary dissection for small carcinoma under local anesthesia in the outpatient clinic. If histopathological examination of the specimens by serial section reveals that the cancer is noninvasive and completely resected with negative surgical margins, no additional surgery under general anesthesia is needed, and the patient does not require hospitalization. We call this procedure "probe lumpectomy". From 1991 to 1998, 169 patients underwent probe lumpectomy in our institution, and there were no major complications. Of these 169 patients, 64 did not require hospitalization. Ipsilateral breast cancer was observed in two patients, and these tumors were diagnosed not as recurrence but as second primary cancers. No distant metastases were observed. As sentinel node biopsy, which is not always easy under local anesthesia, becomes more common, the indications for day surgery or short-stay surgery will expand. As breast cancer is a malignant disease, informed consent and careful follow-up are needed if the treatment is completed only in the outpatient clinic.

Ambulatory Surgical Procedures↗
PubMed1999

Current Status and Controversial Issues concerning Endocrine Therapy for Patients with Recurrent Breast Cancer in Japan.

BACKGROUND: Four different endocrine therapeutic agents have been used in Japan since 1996. However, a consensus regarding proper use of these agents has notyet been established. Therefore, a questionaire survey of Japanese breast cancer authorities on endocrine therapy and a multi-institute survey to investigate the efficacy of a single first-line endocrine therapy for recurrent breast cancerwere conducted. MATERIALS AND PATIENTS: A total of 279 questionaires were sent to the Councilors of the Japanese Breast Cancer Society. The clinico-pathological data of 77 breast cancer patients who underwent a single first-line endocrine therapy were collected from five institutes. RESULTS: The response rate to this questionaire survey was 67.4%. The resultsshow that many authorities consider that: 1) both ER and PgR in primary tumors should be measured, 2) patient age, the disease-free interval and postoperative adjuvant therapy do not provide enough information for the selection of endocrine therapies, 3) antiestrogen and LH-RH agonists should be used as first-line endocrine therapies, 4) combined endocrine therapies, such as an antiestrogen plus an LH-RH agonist, should be used, 5) the optimal sequence of use of endocrine therapeutic agents is most controversial. The objective response rate to first-line endocrine therapies was 40.3% and the duration of response was over 15 months.The objective response rate to second-line endocrine therapies was 42.1%. A multiple regression analysis of predictive factors for the efficacy of first-line endocrine therapies indicated two factors, the disease-free interval and dominantsite of metastasis, to be significant. Conclusions: This questionaire survey suggests that clinical trials to investigate the optimal sequence of use of endocrine therapies and to clarify the usefulness of combined endocrine therapies should be conducted. Single first- or second-line endocrine therapies for recurrent breast cancer are effective and should be carried out by general clinicians.

Journal Article↗
PubMed1999

Correlation of Allelic Loss with Poor Postoperative Survival in Breast Cancer.

BACKGROUND: Allelic losses of tumor suppressor genes or the chromosomal regions harboring them in the DNA of tumor cells may become useful postoperative prognostic indicators. METHODS: To examine whether specific allelic losses correlate with postoperative survival in a five-year prospective follow-up, we tested tumors from a cohort of 504 breast cancer patients for allelic loss of 18 microsatellite markers representing either known tumor suppressor genes or regions where genetic alterations are frequent in breast tumors. RESULTS: Patients with allelic loss at 1p34, 3p25, 8p22, 13q12, 17p13.3, or 17q21.1 had a significantly higher risks of postoperative mortality compared withthose whose tumors retained both alleles at those loci (at 1p34, the 5-year mortality rate was 23% among patients with loss vs 10% with retention, p 0.0100; at 3p25, 22% vs 9%, p =0.0014; at 8p22, 24% vs 7%, p =0.0177; at 13q12, 19%vs 8%, p=0.0093; at 17p13.3, 19% vs 9%, p=0.0078; and at 17q21.1, 17% vs 10%, p =0.0475). CONCLUSION: Allelic losses at these loci can serve as negative prognostic indicators to guide post-operative management, especially in the selection of thosewho will benefit from intensive adjuvant therapies.

Journal Article↗
PubMed1999

Carcinogenicity of heterocyclic amines for the pancreatic duct epithelium in hamsters.

Effects of eight heterocyclic amines (HCAs) on pancreatic duct carcinogenesis were investigated in a rapid production model in hamsters. N-Nitrosobis(2-oxopropyl)amine (BOP) was given to effect initiation, followed by augmentation pressure consisting of four daily i.p. injections of 500 mg/kg DL-ethionine, a choline-deficient (CD) diet, a single i.p. injection of 800 mg/kg L-methionine and a s.c. injection of 20 mg/kg BOP. After two cycles of augmentation pressure, the HCAs 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-9H-pyrido[2,3-b]indole (AalphaC), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAalphaC) or 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline [4,8-DiMeIQx) were administered in the diet for 50 or 70 days. The numbers of pancreatic ductal hyperplasias (H) and a total lesions including, atypical hyperplasia (AH), carcinomas in situ (CIS) and invasive carcinomas, were increased in hamsters given the diet containing 0.02% Trp-P-1 for 50 days. This result was confirmed and extended by the finding of increased numbers of invasive carcinomas in hamsters given 0.02% Trp-P-1 for 70 days. The number and incidence of invasive carcinomas were also elevated in hamsters given the diet containing 0.06% 4,8-DiMeIQx for 50 days. These results suggest a possible involvement of Trp-P-1 and 4,8-DiMeIQx in pancreatic duct carcinogenesis.

Animals↗
PubMed1999

Frequent multiplication of chromosome 1q in non-invasive and papillotubular carcinoma of the breast.

Carcinogenesis is considered to be a multistep process that may involve cumulative genetic alterations; one of these mechanisms, gain of chromosomal material, has the potential to activate tumor-promoting genes in breast carcinogenesis. Using 12 polymorphic microsatellite markers on the long arm of chromosome 1 (1q), we examined 130 sporadic breast carcinomas for abnormalities in the copy numbers of these loci in tumor cells using a differential PCR method. We also sought correlations between alterations on 1q and several clinicopathological parameters. At every locus examined, a 2-3-fold increase in copy number of an allele in tumor material was observed in one third of the tumors (46 of 130, 35%), indicating 'multiplication' of 1q. This multiplication involved the entire long arm in majority of those tumors (43 cases, 93%). The multiplication of 1q was observed more frequently in non-invasive ductal and papillotubular histological types than in solid-tubular and scirrhous types (13/25, 52% vs. 27/90, 30%) (P = 0.041). The predominant chromosomal alterations on 1q in breast carcinomas are found to be multiplications rather than losses. The multiplication represents polysomy of the entire region of 1q, and may confer a growth advantage during development and/or progression of non-invasive ductal and papillotubular histologic types of breast carcinomas.

Adenocarcinoma, Papillary↗
PubMed1999

Restricted occurrence of Lewy bodies in the dorsal vagal nucleus in a patient with late-onset parkinsonism.

Lewy body (LB) is consistently found in the substantia nigra in Parkinson's disease. We report a 68-year-old woman with late-onset, dopa-responsive parkinsonism. Her parents were first cousins, but no other affected individuals were present in the family. Autopsy revealed moderate loss of pigmented neurons with gliosis, but neither LBs nor neurofibrillary tangles in the substantia nigra. The locus ceruleus showed neuronal loss with scarce LBs. The most striking change was found in the dorsal vagal nucleus, where marked neuronal loss and fibrillary gliosis with many LBs were evident. Despite the use of ubiquitin and alpha-synuclein immunohistochemistry, no further LBs were identified in other brain regions. These findings suggest that this case was an unusual, anatomically restricted manifestation of LB disease.

Antiparkinson Agents↗
PubMed1999

Frequent multiplication of chromosomal region 8q24.1 associated with aggressive histologic types of breast cancers.

Carcinogenesis is considered to be a multi-step process that may involve cumulative genetic alterations. One such alteration, gain of chromosomal material, has the potential for activating genes that promote carcinogenesis in breast tissues. Using 14 polymorphic microsatellite markers on the long arm of chromosome 8 (8q), we examined 142 sporadic breast cancers for abnormalities in the copy-numbers of these loci. At each locus examined, a 2- to 3-fold increase in intensities of bands representing single alleles was observed in 57 (40%) of the tumors, indicating that 'multiplication' of the DNA sequence had occurred on 8q. A 16-cM region on 8q24.1 was commonly multiplied among the tumors with partial multiplications. Multiplication on 8q24.1 was observed more frequently in invasive solid-tubular or scirrhous tumors (48/92, 52%) than in less aggressive histologic types (7/25, 28%, P = 0.031). Thus, multiplication of tumor-promoting gene(s) located on 8q24.1 may play a role in the development and/or progression of a substantial proportion of primary breast cancers, particularly those of the invasive histology.

Alleles↗
PubMed1999

Surgical Margin Status as a Cause of Local Failure after Breast Conserving Therapy.

BACKGROUND: To elucidate the cause of in-breast recurrence after breast conserving surgery, we analyzed the characteristics of resected specimens histopathologically, especially the surgical margin status. MATERIALS AND METHODS: 1) Pathological surgical margin positivity was reevaluated in terms of the distance from the resected surgical margin by pathologists from seven institutions in 486 cases with complete stepwise pathological examination. 2) We reviewed pathological specimens including surgical margins from 30 patients with in-breast recurrence for whom serial sections of resected primary breast cancer specimens were available and made comparisons of the time to in-breast recurrence. RESULTS: Cancer cells at the surgical margin were present at a rate of 4.1% on the surface and 15.2% within 5 mm on the areolar side of the surgical margin. Histopathologically, the reasons for local recurrence after breast conserving therapy included a positive surgical margin (21/30), lymphatic permeation (4/30), and others (5/30). The last category included cases with an inadequate margin diagnosis because of a biopsy scar. Disease-free intervals for the patients without postoperative radiotherapy decreased as the volume of cancer cell nests in thesurgical margin increased (P=0.06). On the other hand, this trend was not observed in the group with postoperative radiotherapy. CONCLUSION: Adequate materials are essential for accurate evaluation of surgical margin status. Quantitative evaluation of surgical margin status, apart fromwhether or not radiotherapy was performed, is important for estimating the riskand disease-free period to in-breast recurrence.

Journal Article↗