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Biomedical subjects

A Ogata

Publications and source records attributed to A Ogata.

At least 127 records · Page 7Linked to original sources
PubMed1993

Identification of androgen receptor in the rat spinal motoneurons. Immunohistochemical and immunoblotting analyses with monoclonal antibody.

Androgens play an important role in motoneuron growth, development and regeneration. We proved the existence of androgen receptor (AR) in the motoneurons of the rat spinal cord by the immunohistochemical stain and Western blotting. The possibility that AR protein in spinal cord is expressed in tissue-specific form is proposed, being different from other androgen-dependent tissues. AR abnormality in X-linked spinal and bulbar muscular atrophy (SBMA) among a variety of motor neuron diseases were reported recently. Our study may give some clue to the AR abnormality leading to the degeneration of motoneurons.

Animals↗
PubMed1993

Specific tropism of Japanese encephalitis virus for developing neurons in primary rat brain culture.

Among all the neural cells in fetal rat brain culture developing neurons showed the highest rate of infection by Japanese encephalitis virus (JEV). JEV specifically bound to these cells as measured by immuno-staining. These results indicate that developing neurons are the major target of JEV, and that the initial specific binding of virus to these cells may be one of the reasons for the neurotropism of JEV.

Animals↗
PubMed1993

Portal vein infusion of cancer chemotherapeutic agent emulsified with Lipiodol in regenerating liver after partial hepatectomy in rats.

Portal vein infusion of aclarubicin (ACR) emulsified with Lipiodol (LP) in regenerating liver after 70% partial hepatectomy in rats was evaluated for its safety and usefulness. DNA synthesis in regenerating liver was transiently suppressed by LP, ACR or LP+ACR, but no obvious inhibition was seen in aminopyrine N-demethylase activity and liver weights. LP significantly enhanced hepatic tissue levels of ACR and its active metabolites by long-term retention in the sinusoidal space. This study demonstrates that in rats LP has a powerful effect on the long-term retention of anticancer agents in the sinusoidal space after infusion into the portal vein, without aggravating hepatic damage by anticancer agents.

Aclarubicin↗
PubMed1993

MRI-pathological correlate of brain lesions in a necropsy case of HTLV-I associated myelopathy.

A postmortem case of HTLV-I associated myelopathy (HAM)/tropical spastic paraparesis (TSP) with a history of remission and exacerbation of neurological signs and symptoms, resembling those of multiple sclerosis is reported. MRI analysis revealed lesions in the periventricular white matter in addition to atrophy of the thoracic spinal cord, characteristic of HAM/TSP. The cerebral periventricular areas consisted of ill-defined paucity of myelin sheaths with astrocytic gliosis and hyaline thickening of blood vessels. The poorly demarcated white matter lesions found in both brain and spinal cord were different from plaques found in multiple sclerosis. It is suggested that, in some cases of HAM/TSP, inflammatory lesions that destroy myelin can involve not only the spinal cord but also the cerebral periventricular white matter.

Astrocytes↗
PubMed1993

[Type IV collagenase activities in human colorectal cancers and its role in cancer invasion and metastasis].

In 36 patients with colorectal cancers, type IV collagenase activities were measured in cancer and non-cancer tissues for evaluating its role in the process of cancer invasion and metastasis. The colorectal cancer tissues revealed remarkably higher activities than the distant normal and tumor-neighboring mucosa (p < 0.001). The activities in the colorectal cancer tissues with high-grade histological venous invasion were higher than those with low-grade histological venous invasion (p < 0.005). But no differences of the activities were found between patients with and without hepatic metastasis. These results suggest that the type IV collagenase plays an important role in the cancer invasion to the blood vessels around the primary site in colorectal cancers.

Adult↗
PubMed1992

A new highly sensitive immunoassay for cytokines by dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA).

Non-isotopic immunoassays for human tumor necrosis factor alpha (TNF alpha) and human interleukin-6 (IL-6) were established by employing the dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA) system based on the time-resolved fluoroimmunoassay technique with europium-labeled antibody. Compared to enzyme-linked immunosorbent assays and bioassays, the sensitivity and range of measurement were significantly increased by applying the DELFIA systems to TNF alpha and IL-6. TNF alpha was measurable from 100 fg/ml to 10 ng/ml with the TNF alpha-DELFIA and IL-6 was measurable from 100 fg/ml to 1 ng/ml with the IL-6-DELFIA.

Antibodies, Monoclonal↗
PubMed1992

Anti-interleukin-6 autoantibodies in rheumatic diseases. Increased frequency in the sera of patients with systemic sclerosis.

OBJECTIVE: To investigate the presence and the roles of anti-interleukin-6 (anti-IL-6) autoantibodies in rheumatic diseases, and to further elucidate clinical and pathophysiologic significance of anticytokine autoantibodies. METHODS: Anti-IL-6 IgG autoantibodies were measured by the 125I-IL-6 binding activity of IgG, which was isolated from serum by protein A-Sepharose. RESULTS: Nine of 52 sera (17.3%) from patients with systemic sclerosis (SSc) contained anti-IL-6 antibodies, whereas only 1.9% of sera from normal subjects and 0-5% of sera from patients with other rheumatic diseases were positive for the antibodies. Moreover, anti-IL-6 autoantibodies were found predominantly among patients with the limited form of SSc (42.9%), compared with those with the diffuse form (7.9%). CONCLUSION: Anti-IL-6 IgG autoantibodies were detected in patients with SSc, particularly those with the limited form of the disease, at a significantly increased frequency compared with normal subjects and patients with other rheumatic diseases. These results suggest that the development of anti-IL-6 autoantibodies and IL-6 may have a role in the pathophysiology of SSc.

Adult↗
PubMed1992

Sub-acute toxicity of piperonyl butoxide in F344 rats.

Piperonyl butoxide, alpha-[2-(2-Butoxyethoxy)ethoxy]-4,5-methylenedioxy- 2-propyltoluene, is a pesticide synergist. F344 rats of both sex were maintained on diets containing 0, 0.6, 1.2 or 2.4% of piperonyl butoxide for 13 weeks. At the end of experimental period, they were necropsied. Selected organs were weighted and serum was analyzed by clinical chemistry. In male and female rats of the 2.4%-group, body weight gains were depressed, macroscopically, hepatomegaly was marked and liver weights were significantly higher than those of the control group. In male and female rats of all treated groups, relative kidney weights were significantly increased in a dose-dependent manner. Rats of the 2.4%-group had increased levels of albumin, cholesterol, urea nitrogen and gamma-glutamyl transpeptidase. Examination of livers of the male 2.4%-group by light microscopy showed enlarged hepatocytes with glassy cytoplasm and fatty deposition. On occasion, there was coagulative necrosis of a few hepatocytes in the periportal area and oval cell proliferation. The kidney of treated rats showed atrophy of epithelium in the proximal convoluted tubules. These results indicated that toxicity of piperonyl butoxide in rats was directed primarily to the liver and kidney.

Animals↗
PubMed1992

Biliary interleukin 6 levels as indicators of hepatic allograft rejection in rats.

Interleukin 6 has recently been noted to be present during the rejection response to grafted organs. In this study, we investigated biliary and serum interleukin 6 levels following liver transplantation in rats. IL-6 levels in bile and serum of naive rats were below 0.6 U/ml and 0.5 +/- 0.2 U/ml (mean +/- SD), respectively. Both biliary and serum IL-6 levels showed high values (greater than 10.0 U/ml and greater than 1.6 U/ml, respectively) on the day after transplantation, which seemed to reflect the inflammatory status caused by the surgical stress. Later samplings showed that the kinetics of serum IL-6 differed among the animals without any definite feature related to graft rejection. In contrast, biliary IL-6 levels correlated well with the severity of the rejection response as determined histologically. Biliary IL-6 levels started to rise at the onset of the rejection response (6.6 +/- 0.6 U/ml), increased further with its progression (19.3 +/- 7.8 U/ml), and then finally fell in the terminal stage (less than 2.0 U/ml). Elevation of biliary IL-6 was observed at an early stage when abnormalities could be detected histologically but not in liver function tests and bile flow. Therefore, biliary IL-6 levels may be of value for the early diagnosis of rejection following liver transplantation.

Animals↗
PubMed1992

[Varicella-zoster virus-associated spinal myoclonus without skin lesions].

A 50-year-old woman was admitted to our hospital because of abnormal involuntary movement of upper abdomen. Three months before admission, she had suffered from left lateral chest pain without skin lesions for one week. The neurological examination on admission revealed myoclonus of upper abdomen, and hyperalgesia and thermohyperesthesia from T4 to T9. There was no weakness, the tendon reflexes were symmetrical and the plantar responses were flexor. The surface EMG disclosed the symmetrical, synchronous contractions of m. rectus abdominis and m. obliques externus abdominis. This spinal myoclonus reduced during sleep. The EEG, CT and MRI showed no abnormalities. Serum varicella-zoster virus (VZV) titers increased significantly on follow-up examinations. Clonazepam, 1.5 mg daily was effective in this patient. The myoclonus spontaneously disappeared without clonazepam in six weeks after onset, and at the same time the sensory disturbance also improved. From the neurological findings and clinical course, we consider this spinal myoclonus was probably elicited by involvement of the inhibitory interneurons of the dorsal horns, due to immune response to latent VZV infection but not to direct neuronal destruction by VZV. Spinal myoclonus should be recognized as the spectrum of neurological disease associated with VZV even in the absence of skin lesions.

Female↗
PubMed1992

Interleukin-6 as a new indicator of inflammatory status: detection of serum levels of interleukin-6 and C-reactive protein after surgery.

Postoperative serum interleukin-6 (SIL-6) and C-reactive protein (SCRP) levels were examined in 71 patients who underwent various types of abdominal surgery. Similar time-dependent changes in SIL-6 and SCRP levels were observed in 12 patients despite differences in surgical procedures and liver function among the patients. SIL-6 started to increase within 3 hours after the beginning of the operation and reached a peak after 24 hours. SCRP started to increase after 12 hours and was maximum at 48 to 72 hours. The increase in SIL-6 at 24 hours (delta IL-6) showed a close correlation with that of SCRP at 48 hours (delta CRP) in 53 patients without liver cirrhosis. In 18 patients with liver cirrhosis, delta CRP relative to delta IL-6 was less than that in patients without cirrhosis and was poorly correlated with the latter. delta IL-6 was correlated with the length of time of the operation and blood loss in both groups, but delta CRP showed no significant correlation with these factors in either group. These findings indicate that the increase in IL-6 triggered by a surgical procedure may function as a hepatocyte-stimulating factor and that monitoring of SIL-6 may be more helpful than monitoring of SCRP for estimation of inflammatory status and early detection of an acute-phase response.

Abdomen↗
PubMed1991

Apolipoproteins in rat cerebrospinal fluid: a comparison with plasma lipoprotein metabolism and effect of aging.

Cerebrospinal fluid (CSF) apo E concentrations, determined by a sensitive sandwich ELISA, were 411.3 +/- 76.0 and 454.3 +/- 51.8 micrograms/dl (mean +/- S.D.) for young rats (8-12 weeks old, n = 7) and old rats (36-40 weeks old, n = 10), respectively. Age-related increase, which was conspicuous in serum apo E (21.2 +/- 2.4 vs 60.9 +/- 14.1 mg/dl for young and old rats, respectively), was not observed in CSF apo E. CSF apo A-I concentrations, determined by ELISA, were extremely low in the both groups (less than 10 micrograms/dl). Neither CSF apo A-I nor CSF apo E correlated to any of the plasma lipoprotein components, indicating the presence of largely independent lipoprotein metabolism in the rat central nervous system. Apo E is present in CSF in the form of apo E-rich HDL1 with particle sizes similar to those of plasma E-rich HDL1.

Aging↗
PubMed1991

New metabolites of thiabendazole and the metabolism of thiabendazole by mouse embryo in vivo and in vitro.

Thiabendazole [2-(4'-thiazolyl)benzimidazole; TBZ], a teratogen in ICR mice, is known to be mainly metabolized to 5-hydroxy-TBZ (5-OH-TBZ) and its conjugates in domestic and laboratory animals. Besides the known metabolites of TBZ, 4-hydroxy-TBZ and 2-acetylbenzimidazole (ABI) were identified as new metabolites of TBZ in the urine of F344 rats and ICR mice. 5-OH-TBZ and ABI, as well as TBZ, were found in the embryos of ICR mice given TBZ orally on day 10 of gestation. In the whole-embryo culture system, 5-OH-TBZ and ABI in the medium, and TBZ, 5-OH-TBZ and ABI in the embryo were detected after 24 hr of culture in 25 or 50 micrograms TBZ ml. However, the amount of metabolites in the embryo in vitro was very small compared with that detected in vivo, whereas the amount of TBZ was comparable. Furthermore, the mouse embryo homogenate, at organogenesis, metabolized TBZ to 5-OH-TBZ or ABI. The specific activity required by this homogenate to form 5-OH-TBZ or ABI was less than 1/1000 of that of the liver microsomal fraction. The results suggested that mouse embryos at organogenesis could metabolize TBZ, although most of the metabolites in the embryo in vivo came from the dam.

Animals↗
PubMed1991

Japanese encephalitis virus neurotropism is dependent on the degree of neuronal maturity.

In a study on Fischer rats, all animals infected with Japanese encephalitis virus (JEV) before the age of 13 days died, but animals infected after the age of 14 days did not die, confirming the age-dependent resistance to JEV infection in the rat brain. A study of the kinetics of JEV infection in the developing rat brain disclosed that JEV antigen disappeared in a particular pattern, i.e., from the deeper layers to the upper layers of the motor cortex, which paralleled neuronal maturation in the cortex. Fifteen-day-old rats, which were resistant to JEV infection, received intracerebral transplants of neurons taken from 19-day embryos. When these animals were infected with JEV after transplantation, viral antigen was detected only in the embryonal neurons soon after transplantation. Thus, it can be concluded that the susceptibility to JEV infection in the rat brain is closely associated with neuronal immaturity.

Aging↗
PubMed1991

Two cases of neoplastic angioendotheliomatosis presenting with myelopathy.

We describe two patients with autopsy-proven neoplastic angioendotheliomatosis (NAE) presenting only as a transverse myelopathy for 10 to 12 months, followed by disseminated intracranial manifestations. Postmortem examination disclosed a vasculocentric distribution of neoplastic cells in various organs that stained positively with B-lymphocyte-specific monoclonal antibody. These cases were unusual because they manifested as an isolated myelopathy for many months.

Brain↗