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T Kasuga

Publications and source records attributed to T Kasuga.

At least 55 records · Page 3Linked to original sources
PubMed1994

Three cone systems under white background in the electroretinogram of the cynomolgus monkey.

We recorded electroretinograms for 31 monochromatic (400-700 nm) full-field stimuli at five different adaptation levels from anesthetized cynomolgus monkeys. These waveforms were analyzed by means of a principal component analysis to discuss the relationship between three cone systems with a white background. Under no background, spectral response curves of middle-, long- and short-wavelength cone showed peaks at 517, 579 and 435 nm, respectively, which are in agreement with those of the three cone types. Spectral responses of the middle- and long-wavelength cone systems were increased and decreased, respectively, at the region of 530-590 nm as the level of white background light increased. These opposite changes resulted in the shift of the middle- and long-wavelength cone spectral response peaks to 546 and 609 nm, respectively, which suggests interaction between long- and middle-wavelength cone systems. The peak of the short-wavelength cone system shifted to 452 nm because of decreased responses at the region of 400-450 nm. Therefore, the short-wavelength cone system seems to be mediated by a different mechanism from that involving long- and middle-wavelength cone interaction.

Adaptation, Ocular↗
PubMed1994

Specific expression of the neurofibromatosis type 1 gene (NF1) in the hamster Schwann cell.

The gene responsible for neurofibromatosis type 1 (NF1) has sequence homology to the GTPase-activating protein (GAP) and demonstrates GAP activity against ras p21. To study tissue-specific and/or tumor-specific expression of the NF1 gene product, now called neurofibromin, immunostaining and immunoblotting were applied to the N-nitroso-N-ethylurea (ENU)-induced Syrian hamster neurofibromatosis model using polyclonal antibodies against the NF1 fusion protein and a synthetic peptide. Strong expression was observed specific to the Schwann cells of the normal peripheral nerves by immunostaining. Neoplastic Schwann cells showed specific binding of anti-NF1; however, the frequency of positive cells was diminished. Immunoblotting also revealed positive expression of the 250-kd NF1 gene product in the brain, the normal peripheral nerves, and 7 of 14 ENU-induced neurofibromas. Although ENU-induced melanoma and Wilms' tumor were negative for neurofibromin, foci of Schwannian differentiation in both primary and transplanted melanomas were positive. These results suggest that neurofibromin plays some role in differentiation and growth regulation of the Schwann cell.

Animals↗
PubMed1994

Digital angiotomosynthesis for preoperative evaluation of cerebral arteriovenous malformations and giant aneurysms.

PURPOSE: To evaluate the clinical utility of the digital angiotomosynthesis technique for giving additional information regarding critical anatomy of cerebrovascular lesions before surgical intervention. METHOD: Seven arteriovenous malformations and three giant aneurysms were examined with digital angiotomosynthesis; these images were compared with conventional angiograms. RESULTS: 1) Detailed recognition of three-dimensional vascular structures of the arteriovenous malformation and giant aneurysm was facilitated by the cine mode of digital angiograms and angiotomograms. 2) Reconstructed angiotomograms could show clear separation of overlapping vessels and demonstrate fine vasculature. 3) Fine feeders, which were difficult to trace on the conventional angiogram, were more easily recognized in all cases of arteriovenous malformation. 4) Small arteries passing in close proximity to the arteriovenous malformation nidus were identifiable. 5) Fine arterial branches, being obscured by big shadows of giant aneurysms on the conventional angiograms, were well identified. 6) The anatomic relationship of bone structures to the giant aneurysm was clearly shown. CONCLUSIONS: Digital angiotomosynthesis is helpful for recognizing the three-dimensional and detailed vascular anatomy of arteriovenous malformations and giant aneurysms and provides neurosurgeons with useful information for preoperative evaluation.

Adolescent↗
PubMed1993

[Noninvasive quantitative measurement of cerebral blood flow with 123I-IMP--lung monitoring method].

In order to perform a less invasive determination of regional cerebral blood flow (rCBF) using I-123-IMP, we used the lung clearance curve as a substitute for the arterial blood activity curve as an input function. We assumed that a major portion of the intravenously injected I-123-IMP initially accumulates in the lung and then is gradually cleared from the lung pool to enter the systemic circulation. In this case lung clearance could be considered nearly equal to the integral of arterial blood activity shown during the examination. We used a single probe detector to obtain the lung clearance curve as the difference between sequential lung activity and peak lung activity. The absolute value of the sequential change in arterial blood activity was estimated from the differentiated lung clearance curve compared with the arterial blood activity that was estimated by actual blood sampling once during the examination. The rCBF was calculated by the thus estimated arterial blood activity curve and brain activity by SPECT image using the microsphere model. The values of rCBF obtained by this method were similar to those obtained by the continuous arterial sampling method, and this lung monitoring method was thought to be applicable to clinical use.

Adult↗
PubMed1993

Heterobasidion annosum 5.8s ribosomal DNA and internal transcribed spacer sequence: rapid identification of European intersterility groups by ribosomal DNA restriction polymorphism.

Using conserved fungal ribosomal gene sequences the internal transcribed spacer (ITS) regions one and two (ITS1, ITS2) and the 5.8s ribosomal RNA gene (rRNA) of Heterobasidion annosum were amplified by the polymerase chain reaction (PCR). The nucleotide sequence was determined in three European intersterility groups (ISG-S, -F and -P). Three sequence variants of the ITS were found in ISG-S isolates. The sequence of the ITS of ISG-F differed by two residues from the major ISG-S sequence variant. The ISG-P sequence differed from ISG-S and ISG-F at 15-16 and 16 residues, respectively. Amplified intergenic spacer elements were informative for ISG fingerprinting following digestion with various 4-cutter restriction endonucleases. All differences in the restriction fragments between the ISGs were because of sequence differences in the ITS regions. The fingerprint patterns of isolates from the same intersterility group but from different European localities were identical. These results show that ribosomal DNA fingerprinting is a rapid technique to identify ISGs in Heterobasidion annosum.

Base Sequence↗
PubMed1993

In vivo antimelanoma effects of 4-S-cysteaminylphenol, a newly synthesized therapeutic agent specific to melanoma.

Antimelanoma effects of 4-S-cysteaminylphenol (4-S-CAP), which is a newly synthesized melanin precursor, as a chemotherapeutic agent specific to malignant melanoma were determined in an in vivo system using mouse B16 melanoma. The intraperitoneal injection of 4-S-CAP induced a slight delay in the growth period of subcutaneous melanoma of C57BL/6 mice. Survival times of mice after treatment with 4-S-CAP were a little longer than those of control mice (P < 0.05), although all mice died from the local growth of tumours. The viable cell ratio of in vivo subcutaneous tumour cells reduced to 52.8% within 24 h after treatment with 4-S-CAP, but the ratio had recovered to the control level 72 h after treatment (> 90%). Similarly, the proliferating-cell-nuclear-antigen-positive cell ratio of melanotic melanoma had reduced 24 h after treatment and recovered within 72 h after treatment, while 4-S-CAP had no effect on amelanotic tumours. The formation of lung colonies by intravenous inoculation of malignant melanoma cells was compared between mice with intraperitoneal injection of 4-S-CAP and phosphate-buffered saline only. The 4-S-CAP-treated mice had significantly fewer lung colonies compared with the control mice (P < 0.01). The results indicate that the agent, 4-S-CAP, would have a therapeutic effect on malignant melanoma for a short time in vivo and therefore the agent can be effective against a small number of tumour cells, such as lung colonies, although it had little effect on the local tumours.

Animals↗
PubMed1993

Proliferative activity of primary cutaneous melanocytic tumours.

The expression of proliferating cell nuclear antigen (PCNA) was examined in formalin-fixed paraffin-embedded tissue sections from 41 lesions (27 melanocytic nevi, 3 atypical nevi and 11 malignant melanomas) to determine the proliferative activity of primary cutaneous melanocytic tumours. Most of the malignant melanomas had more than 7% PCNA-positive cells (9.2 +/- 0.5%), while the melanocytic nevi manifested less than 1% PCNA-positive cells (0.4 +/- 0.1%). Atypical nevi exhibited an intermediate, but still significantly lower, labelling ratio when compared with malignant melanomas (0.8 +/- 0.2%). The proliferative activity of the lesions was compared between portions at different depths in the skin (epidermal, upper dermal and lower dermal location). In cases of malignant melanoma, the proliferative activity was higher in the deeper portion of dermis whereas PCNA-positive cells in melanocytic nevi were located in the upper dermis predominantly. Thus the PCNA labelling ratio of malignant melanoma and/or melanocytic nevus cells located in the epidermodermal junction was not necessarily higher than that of malignant melanoma and/or melanocytic nevus cells in the dermis. These results indicate that staining with PCNA would be very useful in the differentiation of malignant melanoma from melanocytic nevi manifesting cellular and/or structural atypia by virtue of a significant difference in the proportion of PCNA-positive cells. Although malignant melanomas have higher proliferative activity than melanocytic nevi in the deeper dermis, junctional activity in melanocytic tumours does not indicate cell proliferation.

Adolescent↗
PubMed1993

Expression of the proliferating cell nuclear antigen in bone marrow cells from patients with myelodysplastic syndromes and aplastic anemia.

To determine the proliferative activity of the hematopoietic cells under nonneoplastic and/or neoplastic conditions, the expression of a cell cycle-related antigen, the proliferating cell nuclear antigen (PCNA), was examined in the bone marrow trephines of 79 individuals, 12 of whom had no hematologic disorder, 32 of whom had a diagnosis of myelodysplastic syndromes (MDSs), 20 of whom suffered from aplastic anemia, and 15 of whom had a diagnosis of acute myeloid leukemia. Most of the patients with MDS had more than 15% PCNA-positive cells (23.5% +/- 1.5%) while patients with no hematologic disorder showed fewer than 15% PCNA-positive cells (11.7% +/- 0.7%). The overall ratio of the PCNA-positive cell fraction in the bone marrow was considered of prognostic value for predicting transition into overt leukemia from MDS. Aplastic anemia cases usually exhibited hypocellular bone marrow and an infrequent labeling with the anti-PCNA antibody (3.3% +/- 0.5%). However, a few aplastic anemia cases showed hypercellular bone marrow and a significantly high PCNA-positive cell ratio (32.0% +/- 4.4%). In the bone marrow of acute myeloid leukemia patients more than 20% of total nucleated cells were positive for PCNA (30.0% +/- 2.2%). The results suggest that the expression of PCNA is associated with the regulation of bone marrow cell proliferation and the bone marrow cellularity, and that these findings would serve as an early indicator of evolution of overt leukemia in MDS and also would be useful in distinguishing MDS cases from aplastic anemia cases when the bone marrow is hypocellular or normocellular.

Acute Disease↗
PubMed1993

Association of Sjögren's syndrome with pulmonary hypertension: report of two cases and review of the literature.

We report two autopsy cases of Sjögren's syndrome associated with pulmonary hypertension. The pulmonary muscular arteries of both cases showed concentric fibrocellular intimal proliferation, medial hypertrophy, and plexiform lesions. To determine the significance and pathogenesis of this rare association, we carried out morphometric and immunofluorescent studies and reviewed the seven similar cases reported in the literature. Depositions of immunoglobulin G, Clq, C3c, C4, and C5 were observed in the pulmonary arterial walls of both of our cases. Morphometric studies revealed increased medial thickness to radius ratios and intimal thickness to radius ratios of the pulmonary muscular arteries in both cases. Previously reported patients were all female, and those cases were frequently associated with Raynaud's phenomenon. This report provides additional and convincing evidence for an association of Sjögren's syndrome and plexogenic pulmonary hypertension based on a detailed study of two cases and a review of the literature. The significance and pathogenesis of this association were examined, but not clarified. However, our studies add to the accumulating data suggesting a link between autoimmune diseases and chronic pulmonary hypertension.

Adult↗
PubMed1993

Regressive and non-regressive thyroid lesions of the rat induced by single injection of N-bis(2-hydroxypropyl)nitrosamine and iodine deficient diet.

Six-week-old male F344 rats were divided into 4 groups. Rats in Groups 1 (n = 16) and 3 (n = 14) received a s.c. injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN) (2800 mg/kg) in experimental week 1 while rats in Groups 2 (n = 5) and 4 (n = 5) received saline. From weeks 2-20, all rats were given an iodine deficient (I-def) diet and tap water. Groups 1 and 2 were killed for the measurements of thyroid-stimulating hormone (TSH), thyroxine (T4), the maximum thyroid width (MTW), thyroid weight, morphology, morphometrics and proliferating cell nuclear antigen (PCNA) labeling index (LI). The thyroids of the rats in Group 3 and 4 were surgically exposed and the MTWs were measured. These latter rats were given basal diet for 6 weeks to recover from iodine deficiency, and then killed for the same measurements. Thyroid nodular lesions in Group 1 rats were classified into five categories (NL0, NL1, NL2, NL3 and NL4) based upon incremental cellular and structural atypia. Two types of regressive nodules (NL'0 and NL'1+2) were identified in the recovered rats as the regressed form of NL0, NL1 and NL2 lesions. NL3 and NL4 nodules were seen in Groups 1 and 3. The mean number of combined NL0, NL1 or NL2 lesions was 28.44 +/- 6.12 nodules per rat (NPR) in Group 1 rats and the mean number of NL'0 and NL'1+2 lesions was 28.07 +/- 13.05 NPR in Group 3 rats. The mean number of NL3 or NL4 lesions was 1.70 NPR in Group 1 rats and 3.42 NPR in Group 3 rats. The LIs were NL0 (6.4 +/- 2.5%), NL1 (7.7 +/- 4.4%), NL2 (0.7 +/- 0.3%), NL3 (7.5 +/- 1.3%) and NL4 (14.4 +/- 5.3%) in Group 1 rats and NL'0 (< 0.001%), NL'1 + 2 (< 0.01%), NL3 (9.0 +/- 4.4%) and NL4 (23.3 +/- 17.8%) in Group 3 rats. The thyroid weights of Group 4 rats were 41% of Group 2 rats. The volume fraction (VF) of the non-NL3, non-NL4 areas in Group 3 rats was 40% of that in Group 1 rats. However, the VF of NL3 or NL4 lesions in Group 3 rats was 520% of that of Group 1 rats. In summary, the growth of the NL0, NL1 and NL2 lesions was TSH-dependent, whereas NL3 and NL4 lesions were TSH-independent.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

N-nitroso-N-ethylurea-induced hamster melanoma: a new method for efficient induction and schwannian differentiation of melanoma.

Melanocytic tumors as well as multiple neurofibromas were induced in 35 of 88 Syrian golden hamsters by a single s.c. administration of 100 mg/kg of N-nitroso-N-ethylurea applied 48 h after birth. The lesions were all observed proliferating in the dermis and demonstrated melanosomes and premelanosomes. High cellularity, nuclear atypia and transplantability of the tumors in outbred hamsters suggested a malignant nature. Some of the melanomas were morphologically heterogenous and contained Schwann-like cells as minor components. In addition, transplantation of the melanomas resulted in increased schwannian differentiation even for primary tumors which did not contain any Schwann-like cell foci. One of the transplanted melanomas mimicked malignant peripheral nervous tumor. Schwannian differentiation was also proved by the fact that glial fibrillary acidic protein was positive in 22.2% of the cases. The present results suggest that the induced hamster melanomas originate from neural crest-derived cells which are able to differentiate into both melanocytes and Schwann cells.

Animals↗
PubMed1993

Chest imaging with dual-energy subtraction digital tomosynthesis.

Dual-energy subtraction digital tomosynthesis with pulsed X-ray and rapid kV switching was used to examine calcifications in pulmonary lesions. The digital tomosynthesis system used included a conventional fluororadiographic TV unit with linear tomographic capabilities, a high resolution video camera, and an image processing unit. Low-voltage, high-voltage, and soft tissue subtracted or bone subtracted tomograms of any desired layer height were reconstructed from the image data acquired during a single tomographic swing. Calcifications, as well as their characteristics and distribution in pulmonary lesions, were clearly shown. The images also permitted discrimination of calcifications from dense fibrotic lesions. This technique was effective in demonstrating calcifications together with a solitary mass or disseminated nodules.

Humans↗
PubMed1993

Friend leukemia virus-induced leukemogenesis in fully H-2 incompatible C57BL/6-->C3H radiation bone marrow chimeras.

Resistance and/or susceptibility for Friend leukemia virus (FLV)-induced leukemogenesis was examined in the fully H-2 incompatible C57BL/6 (B6)-->C3H radiation bone marrow chimeras (RBMC). The results indicated that B6-->C3H chimeras never developed FLV-induced leukemias when infected with FLV 4 months after bone marrow transplantation (BMT). Spleen cells from B6-->C3H chimeras that were preimmunized with 100 Gy-irradiated FBL-3 cells (FLV-induced leukemic cell line originated from B6 mice) were shown to generate anti-FBL-3 specific T-cell proliferation as well as cytotoxic T cells. We also found that when bone marrow cells from B6 mice were mixed with those from C3H mice and then grafted into supralethally irradiated C3H mice, resulting chimeras whose peripheral blood contained less than 30% C3H-derived (susceptible) cells were refractory to FLV-induced leukemogenesis. On the other hand, when C3H mice were infected with FLV and then supralethally irradiated 5 days later and grafted with bone marrow from B6 donors, they developed leukemias which were of B6 origin. Athymic nu/nu mice of B6 background were again shown to develop leukemia following infection with FLV. Possible implication of these findings on the role of T cell-mediated immune response in resistance to FLV-induced leukemogenesis and the immunocompetent nature of fully H-2 incompatible RBMC were discussed.

Animals↗
PubMed1992

Cardiac metastasis of lung cancer. A study of metastatic pathways and clinical manifestations.

BACKGROUND: Although lung cancer frequently spreads to the heart, details of cardiac metastases of lung cancer have not been fully discussed. The authors attempted to elucidate the relationship between the mechanisms of cardiac metastasis and a variety of clinical manifestations caused by cardiac metastasis. METHODS: Clinical and autopsy records were reviewed in 74 autopsied cases of lung cancer. In cases with cardiac metastasis, the metastatic pathways to the heart were determined by the macroscopic examinations, and the relationship between the metastatic pathways and the clinical manifestations were studied. RESULTS: Metastases to the pericardium or heart were seen in 23 cases (31%). A lymphatic metastatic pathway was detected in 18 cases (hilar lymphatic routing in 12 cases, and mediastinal lymphatic routing in 6 cases), and a hematogenous metastatic pathway was detected in 5 cases. Malignant pericardial effusion was documented in 15 of 23 cases. The metastatic pathway in 14 of 15 cases was lymphatic (hilar lymphatic routing in 10 cases, and mediastinal lymphatic routing in 4 cases). Patients showing lymphatic metastasis had higher incidence of malignant pericardial effusion than those with hematogenous metastasis (P less than 0.05). Of 23 cases of cardiac metastasis, myocardial infarction was found in 1 case, resulting from the compression of the coronary arteries by the tumor. Concurrent supraventricular arrhythmias were recorded in eight cases with cardiac metastasis. Patients with cardiac metastasis had higher incidence of arrhythmia than those without cardiac metastasis (P less than 0.05). In cases of cardiac metastasis, patients with arrhythmia were older (P less than 0.01) than those without arrhythmia. CONCLUSIONS: The authors concluded that the hilar lymphatic pathway is essential for early development of malignant pericardial effusion in lung cancer and that aging and cardiac metastasis may be responsible for arrhythmia in patients with lung cancer.

Age Factors↗
PubMed1992

Incidence of atypical bronchioloalveolar cell hyperplasia of the lung: relation to histological subtypes of lung cancer.

The incidence of atypical bronchioloalveolar cell hyperplasia (ABH) of the lung was investigated to evaluate the possibility of this lesion being a precancerous stage in the histogenesis of adneocarcinoma. Lobectomy and pneumonectomy specimens of 165 primary and 45 metastatic tumour cases were step-sectioned horizontally and examined histologically. An average of 51 blocks were taken in each case. Sixty-seven ABHs up to 10 mm in diameter were detected, only 2 lesions being associated with scar tissue. Age was one factor apparently related to ABH development, although not the major one. There was no correlation between smoking index and ABH occurrence. In males, the incidence was highest in association with adenocarcinoma (25.5% of cases, 0.8% of sections), followed by large cell carcinoma (25.0% of cases), squamous cell carcinoma (10.5% of cases) and metastatic tumours from other sites (4.8% of cases). In females, ABH was also more common together with adenocarcinoma (8.3% of cases) than with metastatic tumours (4.0% of cases). The differences in male incidences by case and by section between the adenocarcinoma and metastatic tumour categories were statistically significant (P less than 0.05, P less than 0.01 respectively) indicating that ABH may be a precancerous lesion capable of transformation of adenocarcinoma.

Adenocarcinoma↗