Biomedical subjects

Y Takekawa

Publications and source records attributed to Y Takekawa.

At least 19 recordsLinked to original sources

PubMed2001

Fragmentation reactions of optically active trisubstituted cyclopropylcarbinyl radicals.

Fragmentation reactions of optically active trisubstituted cyclopropylcarbinyl radicals and their application to the synthesis of natural products are described. Preparation of the optically pure substrates for radical fragmentation reactions was efficiently accomplished by lipase-mediated desymmetrization of sigma-symmetrical 3-substituted-1,2-cyclopropanedimethanols. In the presence of a radical stabilizing group, e.g., aryl, ester, or alpha,beta-unsaturated ester, the fragmentation occurs selectively to generate the radical on the alpha-carbon of the group and provide the optically pure alkene derivatives. These derivatives possess three chemically distinct functionalities, making them excellent chiral building blocks for the construction of biologically active molecules. The synthetic usefulness of the procedure developed here has been demonstrated by an application to the enantioselective synthesis of both enantiomers of the key intermediate, 4-(3,4-methylenedioxybenzyl)dihydrofuran-2(3H)-one (54), for the total synthesis of biologically active lignans.

Alkenes↗

PubMed2001

A case of undifferentiated glioma in a 70-year-old woman.

The present case involved a 70-year-old woman who was diagnosed with a right cerebral hemorrhage. Excisional surgery of the hematoma was performed. Grossly, a whitish, solid tumor (1 x 1 x 0.8 cm in size) was recognized in the hematoma. Histologically, the tumor was composed of large, polygonal cells and small undifferentiated cells in a jumbled architectural arrangement with a cartilage component. The large, polygonal cell component was conspicuous and somewhat rhabdoid in appearance and appeared to be an astrocytic tumor showing glial differentiation. The small, undifferentiated cell component resembled tumor cells of a primitive neuroectodermal tumor (PNET). Clinical follow-up of the patient for 2 months after the first operation revealed recurrence with rapid growth. A second operation was performed, but the patient died 8 months after the first operation (2 months after the second). Immunohistochemically, the tumor cells suggesting glial differentiation were positive for glial fibrillary acidic protein (GFAP), S-100, neuron-specific enolase (NSE), and vimentin. PNET-like components in the primary tumor were positive for NSE, GFAP, and S-100, and weakly positive for vimentin and synaptophysin. Each tumor cell was negative for epithelial membrane antigen (EMA), keratin, desmin, actin, myoglobin, neurofilament (NF), and MIC2 protein. The recurrent tumor revealed predominantly PNET-like components; however, only a few tumor cells were positive for GFAP. This appearance suggested that this brain tumor might originate from a common multipotential stem cell. Considering its histopathological and immunohistochemical characteristics, the primary tumor was finally regarded as an undifferentiated glioma with dedifferentiation of the glial component in the recurrent tumor.

Aged↗

PubMed2001

[Pathological, cytological and immunohistochemical study of normal-sized ovary carcinoma syndrome].

Normal-sized ovary carcinoma syndrome(NOCS) is characterized by diffuse metastatic malignant disease of the abdominal cavity in females, with normal-sized ovaries, and no origin assigned definitively by intraoperative evaluation. To elucidate the characteristics of NOCS arising from ovarian carcinoma, we investigated the immunohistochemical reactivities of keratin, epithelial membrane antigen(EMA), vimentin, and proliferative cell nuclear antigen(PCNA) in 4 cases of ovarian carcinoma with NOCS(NOCS group), including 3 cases of serous surface papillary adenocarcinoma(SSPC) and 1 case of small ovarian primary serous papillary adenocarcinoma(SPC). These cases were compared with 3 cases of ovarian carcinoma without NOCS(non-NOCS group), including 3 cases of SPC. Cytological and histological testing of the NOCS and non-NOCS groups showed the same findings. Similar reactivities for keratin, EMA and vimentin were observed in the NOCS and non-NOCS groups. No significant change of PCNA labeling index between the groups was seen. However, clinical stage of the NOCS group was higher than that of non-NOCS group. It was hypothesized that exposure of cancer cells to peritoneal cavity in ovarian SSPC leads to the spread. In NOCS case arising from small-sized ovarian carcinoma, another factor was thought to be involved, such as genetic alteration, but it is not known.

Aged↗

PubMed2001

[A case of breast cancer with bone marrow and liver metastases responding completely to low-dose weekly paclitaxel combined with toremifene].

A 36-year-old woman was admitted to our hospital because of general malaise in October 1999. She was diagnosed with bilateral breast cancer with bone marrow and liver metastases. Low-dose weekly paclitaxel (60 mg/body/week) combined with toremifene (120 mg/day) was started in December 1999. Myelofunction was recovered after 2 weeks of chemotherapy (CT), and the primary tumors and cervical/axillary lymphadenopathy disappeared after 4 weeks of CT. Bone marrow and liver metastases was no longer detected after 16 weeks of CT, and the case was evaluated as a complete response (CR). The same therapy has been performed for eight months and no evidence of recurrence has been observed.

Adult↗

PubMed2000

Pathologic, cytologic and immunohistochemical findings of an intra-abdominal desmoplastic small round cell tumor in a 15-year-old male.

The intra-abdominal desmoplastic small round cell tumor is a rare neoplasm. It usually occurs in young males and diffusely involves the peritoneum and pursues an aggressive clinical course. The present patient was a 15-year-old male who experienced abdominal pain and abdominal swelling. The patient was diagnosed with an intestinal myogenic sarcoma, and surgery for tumor resection was performed in June 1999. The tumor was a 20 x 15 x 15 cm well-defined mass in the peritoneum involving the transverse colon and stomach with peritoneal disseminations and splenic metastasis. Microscopic findings were well-defined nests composed of small round cells and separated by abundant desmoplastic stroma. Cytologically, the tumor cells consisted of small, round to oval cells with a scant amount of light blue cytoplasm. Immunohistochemically, the tumor cells were positive for anti-epithelial membrane antigen, vimentin, desmin, neuron-specific enolase and WT1 protein antibodies. Similar pathologic features with other small round cell tumors may lead to differential diagnostic difficulties that require the application of ancillary diagnostic methods, such as immunohistochemistry and cytogenetic techniques.

12E7 Antigen↗

PubMed1999

Expression of apoptosis and its related protein in astrocytic tumors.

The relationship between malignant potential and apoptosis in astrocytic tumors has not been clearly defined, and further classification of astrocytic tumors is necessary. To elucidate the relationship between the histopathological grade of astrocytic tumors and apoptosis, we studied 25 cases of astrocytic tumors, comprising 10 cases of glioblastoma (GB), 7 cases of anaplastic astrocytoma (AA), and 8 cases of astrocytoma (AC). We detected apoptosis using the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) method. We studied immunohistochemical expression of bcl-2 protein and p53 protein, which are apoptosis-related factors, and cell proliferative activity using Ki-67 antibody. No significant change was noted between apoptotic index and the histological grade of the tumors. In GB, apoptotic cell-rich foci were present at the pseudopalisading necrosis. No correlation between histopathological grades and expression of either p53 or bcl-2 was observed. In GB, however, poor distribution of bcl-2 was found in the areas of pseudopalisade formation. bcl-2 is one of the regulatory factors in the cell cycle and inhibits apoptosis. Expression of apoptosis had no correlation with histopathological grade. However, in GB, the distribution of apoptotic cells showed a correlation with bcl-2-poor foci. It was thought that apoptosis was one of the regulatory factors in the formation of pseudopalisading necrosis in GB.

Adolescent↗

PubMed1999

Expression of the multidrug-resistance P-glycoprotein (Pgp, MDR-1) by endothelial cells of the neovasculature in central nervous system tumors.

To elucidate the expression of the MDR1 gene products P-glycoprotein (Pgp) in endothelial cells of newly formed blood microvessels in brain tumors, 30 brain tumors were examined by immunohistochemistry using an anti-Pgp monoclonal antibody, JSB-1. Positive reactions for JSB-1 were detected in endothelial cells in newly formed microvessels in all 16 cases of glioma but not in the 4 meningiomas. Although endothelial cells in newly formed microvessels of all 10 metastatic carcinomas showed positive reactions, negative reactions were seen in those of the primary carcinomas. Compared with reactions of the endothelial cells of normal cerebral capillaries, weak reactions were found in the endothelial cells forming glomeruloid proliferation in newly formed microvessels in the eight glioblastomas and at the border of the surrounding cerebral tissue of the metastatic carcinomas. Since the endothelial cells showing glomeruloid proliferation also had a high proliferative cell nuclear antigen labeling index, the present findings demonstrate a negative relationship between positive reactions for Pgp and the proliferative activities of endothelial cells in cerebral capillaries.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Symptom classification of schizophrenia changes with the duration of illness.

Our starting hypothesis was that schizophrenic symptomatology changes over time. This hypothesis explains conflicting reports on schizophrenic symptom structures as a consequence of different durations of illness in the samples studied to date. Therefore a sample of 258 schizophrenic in-patients (with ICD-10 diagnoses F20) was categorized according to illness duration. A factor analysis was performed on the 8 items of the Manchester Scale for three subgroups (duration < 10 years, 10> or =20 years and > or = 20 years). For those patients whose illness duration was less than 10 years, 'formal thought disorder' was not related to any other mental state, whereas for those whose duration was 10 years or longer, it was correlated with 'negative symptoms'. In the < 10 years group, 'anxiety and depression syndrome' and 'positive symptoms' formed one complex, but these symptoms were separated into two distinct syndromes in the > or = 20 years group. Thus we were able to demonstrate that the classification of symptoms changes with increasing duration of illness.

Adolescent↗

PubMed1999

Criteria defining refractory schizophrenia.

To date there has been no agreement with regard to the criteria that define refractory schizophrenia. In this study, we intended to clarify the criteria which psychiatrists use to judge schizophrenic patients as being refractory in Japan. Based on 258 schizophrenic in-patients (ICD-10) and their likelihood of discharge, level of psychosocial functioning, mental state and use of medication, the common features of patients who are viewed as non-dischargeable because of their severe mental state, compared to those of dischargeable patients, were extracted and used as the criteria. The criteria proposed necessitate (i) diagnosis of schizophrenia by standard operational criteria, (ii) continuous hospitalization for at least the past 2 years, (iii) a level of psychosocial functioning of < or = 40 as measured by the Global Assessment Scale, and (iv) an intensity score of 'marked' or 'severe' on at least three of the six Manchester Scale items (flattened affect, psychomotor retardation, delusions, hallucinations, incoherence of speech and poverty of speech).

Adult↗

PubMed1999

[Immunohistochemical study of Sertoli-stromal cell tumor; comparison between the tumor arising from the gonad of a testicular feminization syndrome bearing patient and from ovaries of non-bearing patients].

The association of Sertoli-stromal cell tumor with testicular feminization syndrome (TFS) has been elaborated in the past studies. Here, we described immunohistochemical studies on Sertoli cell tumor of the gonad in a TFS patient and compare with 2 other cases of spontaneous ovarian Sertoli-stromal tumor. [Case 1] The case was a 73 year-old Japanese patient (46XY karyotype), who had had primary amenorrhea. High level of testosterone was noted in laboratory investigation (1900 ng/ml). No ambiguous morphology of external genitalia was present, but atrophy of vagina was noted. The patient was diagnosed as TFS. A left gonadal tumor was identified histologically showing well differentiated Sertoli cell tumor. The tumor cells were positive for anti-vimentin antibody but negative for anti-keratin, EMA and p53 antibodies by immunohistochemistry. The right gonad was an immature testis. [Case 2] The case was a 33 year-old female with ovarian Sertoli-Leydig cell tumor. Immunohistochemically, positive reaction for anti-keratin and p53 antibodies were observed. [Case 3] The case was a 17 year-old female with moderately differentiated Sertoli cell tumor of the ovary. The tumor cells were positive for anti-keratin, EMA and p53 antibodies by immunohistochemistry. Difference in immunohistochemical reactions between Sertoli cell tumor in TFS and Sertoli-stromal cell tumors of the ovaries was probably due to variation in the degree of gonadal development.

Adolescent↗

PubMed1998

Vascular endothelial growth factor and neovascularization in astrocytic tumors.

It has been widely recognized that the vascular structure is an important factor when making a histopathological diagnosis and assessing the malignancy potential, especially of astrocytic tumors. The vascular endothelial growth factor (VEGF), which is thought to be regulated by the p53 gene, is a regulation factor for tumor neovascularization. The relationship between VEGF distribution and neovasculature was studied in 42 cases of astrocytic tumors (grades 1-4), which were obtained from surgical material, and the St Anne-Mayo grading system was applied. The relationship between the labeling indices (LI) of VEGF and LI of p53 protein in tumor cells was also studied using immunohistochemistry. The VEGF LI in high-grade malignancy potential tumors, such as grade 3 and grade 4 tumors, was significantly higher than those that were low grade. In grade 4 tumors, a significant correlation between the VEGF LI and the proliferation indices of endothelial cells of neovasculatures was observed. No significant correlation was noted between p53 LI and VEGF LI, as well as p53 LI and histopathological grade. In astrocytic tumors, expression of VEGF may be correlated to tumor neovascularization, and can be considered as an indicator of malignancy potential in astrocytic tumors.

Adolescent↗

PubMed1998

[Usefulness of cytology applied simultaneously to frozen section at rapid intraoperative diagnosis of intracranial tumors].

We discussed usefulness of cytology for rapid intraoperative diagnosis of intracranial tumors using frozen section. Twenty five cases of intracranial tumors (6 cases of astrocytoma, 6 cases of glioblastoma multiforme, 4 cases of meningioma, 2 cases of pituitary adenoma, 1 case of ependymoma and 6 cases of metastatic carcinoma) were observed by cytological specimen, frozen section and formalin fixed-paraffin embedded section. When only frozen section were used for histopathological diagnosis, it was difficult to diagnose in a few case of astrocytic tumors by artifact in freezing process. When only cytological specimen were used for diagnosis, histological findings, for example pseudopalisading around necrosis in glioblastoma or rosette formation in ependymoma, were not identified. However, diagnostic accuracy were improved when both cytological and frozen specimen were used if adequate material were obtained for diagnosis. In conclusion, cytological approach used in addition to frozen section was useful for rapid intraoperative diagnosis.

Adenoma↗

PubMed1997

Experimental investigation of battery-induced esophageal burn injury in rabbits.

OBJECTIVE: In recent years, small high-performance batteries have become very popular. With this increasing miniaturization of batteries, clinicians have noted an increasing frequency rate of esophageal injury due to battery ingestion by infants. The situation is associated with severe injury to the esophagus due to the electrical current produced, particularly in the case of high-performance batteries producing high currents. The pathophysiologic features and complications of esophageal battery burns have not been thoroughly investigated. Our study intended to investigate the pathophysiologic features and complications of esophageal battery burn. DESIGN: Open, randomized, controlled study. SETTING: Experimental animal laboratory in a university hospital. SUBJECTS: Male adult mixed-breed rabbits, 22 wks old and weighing 3 to 3.5 kg. INTERVENTIONS: The experimental rabbit model of esophageal injury due to battery ingestion described herein was designed to study not only the direct influence of contact with the battery but also damage to neighboring tissues and the biochemical and pathologic mechanisms of injury. We investigated the relationship between the direction of the inserted battery and the mechanism underlying these complications. Esophageal burn injury was created by placing a 3-V battery into the esophagus for 9 hrs. MEASUREMENTS AND MAIN RESULTS: The cathode side of the esophagus became increasingly alkaline, while the anode side was acidic. Low-voltage battery burns are likely to be due to secondary chemical reactions caused by the electric current because of acid generated at the anode and alkali at the cathode using a micro pH meter. Injury was significantly more severe on the alkaline side when a battery was placed with its cathode directed toward the trachea. Alkaline complications affecting neighboring tissues were more severe than acid complications. These results indicate that as well as the esophageal mucosa itself being injured, deleterious effects are exerted on surrounding tissues, the severity of which vary depending on the orientation and duration of the battery being lodged in the esophagus. CONCLUSIONS: The direction of the battery cathode, which produces alkali, is important in determining the severity of complications. Based on our investigation of the underlying mechanisms of these complications, we advocate the establishment of treatment guidelines for battery swallowing accidents.

Animals↗

PubMed1997

[Mitochondrial neurogastrointestinal encephalomyopathy presenting with protein-losing gastroenteropathy and serum copper deficiency: a case report].

We report a 56-year old female with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), presenting with protein-losing gastroenteropathy and serum copper deficiency. There was no neuromuscular disease in her family members. Three years prior to admission, she developed severe gastrointestinal symptoms including diarrhea, nausea, vomiting and ascites, and was diagnosed as having protein-losing gastroenteropathy based on alpha(1)-antitrypsin clearance and other tests. She was referred to our department when neurological symptoms were apparent. Neurological examinations revealed bilateral ptosis, ophthalmoplegia, hearing loss, facial and limb muscle weakness, mild sensory deficit of vibration on her feet and hypoactive deep tendon reflexes. Pigmentary retinopathy, cerebellar ataxia and heart block were not seen. Serum copper level was decreased to 45 micrograms/dl (normal: 83-155). Chronic intestinal pseudo-obstruction was proven by X-ray studies, and diffuse leukoencephalopathy demonstrated on brain MRI. On EMG, motor nerve conduction velocities were prolonged with temporal dispersion. Her muscle biopsy from biceps brachii muscle showed both neuropathic and myopathic changes, scattered ragged-red fibers and focal cytochrome c oxidase deficiency. Southern blot and polymerase chain reaction analysis on mitochondrial DNA showed no deletions nor point mutations. The clinical and pathologic findings of the present patient fulfilled the diagnostic criteria of mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) proposed by Hirano et al. There are few reported patients with MNGIE in Japan, but none presented with protein-losing gastroenteropathy and serum copper deficiency. Since the copper is a cofactor of cytochrome c oxidase, decreased serum copper level may aggravate the respiratory chain enzyme metabolism in mitochondria. Therefore, treatment for gastrointestinal tract disturbance and copper administration may be necessary to prevent disease progression.

Brain↗

PubMed1996

Correlation of two argyrophilic nucleolar organizer region counting methods with the Ki-67 labeling index in uterine smooth muscle cell tumors.

The argyrophilic nucleolar organizer regions (AgNOR) are silver stained granules that are thought to correlate with cell proliferation activity. Two AgNOR counting methods: the mean AgNOR count (mAgNOR, the mean number of AgNOR granules in 100 cells) and the AgNOR proliferative index (pAgNOR, the percentage of cells exhibiting five or more AgNOR granules per nuclei) have been proposed. In this study, the two counting methods were applied to 58 cases of normal uterine corpus and uterine corpus tumors and were compared with the Ki-67 labeling index (Ki-67 LI) using MIB-1 monoclonal antibody and other histopathological criteria. Notable differences in the number of AgNOR and the Ki-67 LI were observed between benign and malignant smooth muscle tissue. Histopathologic features are well correlated to the proliferative activity of tumors. Although the most reliable method of predicting malignant potential cannot be determined, the methods outlined by this study are thought to be highly useful in assessing proliferative activities.

Cell Count↗

PubMed1996

[Comparison of biochemical properties of human airway tryptase isolated from mucoid sputum with those of lung mast cell tryptase].

We found a novel trypsin-like enzyme (tryptase) in sputum from patients with chronic airway diseases, and named this enzyme human airway tryptase (HAT). To clarify its physiological significance in the airway, we compared biochemical properties of purified HAT with those of purified lung mast cell tryptase (MCT). Studies with model peptide substrates showed that both the HAT and MCT preferentially cleaved the COOH-terminal side of arginine residues of certain peptides, but substrate specificities to nine synthetic model substrates of HAT differed from those of MCT. Effects of protease inhibitors on the two enzymes were examined at a concentration of 10 microM. Both the HAT and MCT were strongly inhibited by the trypsin inhibitors leupeptin, antipain, and aprotinin. An alpha-1-protease inhibitor inhibited HAT by 50%, but it did not inhibit MCT. In contrast, a secretory leukocyte protease inhibitor strongly inhibited MCT, but not HAT. Mucoid sputum from patients with chronic bronchitis contained much more HAT than MCT. These differences in biochemical properties between HAT and MCT indicate that they play different physiological roles in the airways.

Asthma↗

PubMed1995

[Immunohistochemical study of proliferation index of astrocytomas classified by new histopathological grading].

A new grading method of astrocytoma, proposed by Daumas-Duport et al, was based on four criteria:nuclear atypia, mitosis, necrosis and endothelial proliferation (0 criteria = Grade 1, 1 criteria = Grade 2, 2 criteria = Grade 3, 3 or 4 criteria = Grade 4). To elucidate the correlation of the classification based on four criteria, cellularity and proliferative activities, we studied proliferating index of 67 astrocytomas, using immunohistochemical staining for Ki-67 antibodies (MIB-1). A new grading method was related to proliferating index in this study, however, cellularity of tumor cells was not related to proliferating index. In this study, endothelial proliferation was invariably seen in high grade(Grade 3 and 4) astrocytomas. These tumor vessels were associated with dysfunction of blood-brain barrier and some growth factors accelerated to tumor cell proliferation. Relation between histopathological grade of astrocytoma and proliferation index was supposed, and new grading system was thought to be useful for routine pathological examination.

Adolescent↗

PubMed1993

[Roles of pathology laboratories on medical care service and quality assessment system for pathological diagnosis].

In practical medicine, pathologists provide highly specialized medical information (pathological diagnosis) to clinicians. Pathological diagnosis includes histopathology, cytology, intraoperative consultation (rapid diagnosis by frozen section) and autopsy service. In particular, histopathological diagnosis of biopsy specimens, nearly always gives a qualitative diagnosis to unknown pathological process, in other words, a final diagnosis. In addition, pathological diagnosis contributes to supporting medical audit. Thus it is quite important that to establish the quality assessment system for pathological diagnosis which is hard to be judged with the value.

Autopsy↗