Biomedical subjects

H Mogami

Publications and source records attributed to H Mogami.

At least 55 records · Page 3Linked to original sources

PubMed1990

[Antitumor activity of FK973 for malignant gliomas and its assessment for normal brain cells].

FK973, a novel antitumor antibiotic, was obtained as a fermentation product of Streptomyces sandaensis. FK973 had excellent cytotoxic effects against in vitro cultured human glioblastomas, medulloblastomas, and murine glioma (203 glioma) cells. The antitumor effects were also well observed against ACNU resistant glioma cells. FK973 did not go through the blood-brain barrier. The median survival time (MST) of MG models treated with FK973 was 21 days. On the other hand, the MST of the control group was 15 days. In the in vitro assessment against neural disturbance, FK973 showed a little disturbance of murine brain cells but less toxic than ADM. In the in vivo neurotoxicity examination, FK973 showed no clear damage to the neural cells and myelin sheaths.

Animals↗

PubMed1990

[Scrotal scintigraphy in varicocele compared with physical examination and venography].

Scrotal scintigraphy using a gamma-camera and 740 MBq of 99mTc-labeled human serum albumin was performed on 43 patients with suspected varicocele. In 39 patients (37 left-sided, 2 bilateral) with proven varicoceles, sensitivities by the static and dynamic images were 92.3% and 51.3%, respectively. There were no false positive cases in either image (4 cases with no varicocele). It has been suggested that static images are useful for the detection of varicocele in infertile men. A comparison between the static and clinical grades showed that the static grades appeared to become higher in proportion to the clinical grades. A comparison between the static grades and the diameter of the internal spermatic vein (ISV) showed that the mean value of the diameter of the ISV in SG 1, SG 2 and SG 3 was 4.1 +/- 0.66 mm, 5.1 +/- 0.68 mm, and 6.2 +/- 0.79 mm, respectively. Patients with higher static grades had ISVs of significantly larger diameter (SG 1 vs SG 2; p less than 0.05, SG2 vs SG3; p less than 0.01, SG 1 vs SG 3; p less than 0.01, t-test). A comparison between the dynamic images and the degree of reflux in the ISV showed that patients with positive dynamic images had a significantly greater degree of reflux (p less than 0.01, Chi-square test). From these observations, scintigraphic findings would reflect the degree of reflux in the ISV, the diameter of ISV, and the size of the varicocele. Furthermore, from the remarkable changes between pre- and post-therapeutic findings on the scintigrams, therapeutic effects could be easily and objectively assessed by scintigraphy.

Adolescent↗

PubMed1990

[Role of CT and ultrasonography in acute blunt trauma of the abdomen].

From March 1985 to April 1989, one hundred thirty-one patients were examined using computed tomography (CT) and/or ultrasonography (US) in the evaluation of acute blunt trauma of the abdomen (CT and US in 36 patients, CT in 25 US in 70). Twenty-three out of the 131 cases (17.6%) showed positive findings of abdominal trauma on CT and/or US. Sixteen of the 23 patients with positive findings underwent therapeutic laparotomy, while all of the other 108 patients with negative findings were successfully managed conservatively. This fact suggests that one of the roles of CT and/or US is to pick up patients with negative findings who do not have any laparotomy. Free fluid collection was demonstrated in all of the 23 patients with positive findings in: all 22 on CT (100%), and 13 of 14 on US (92.9%). In all of the 23 patients but one with an injured mesenterium, injured organ was demonstrated by CT and/or US in: 21 of 22 by CT (95.5%), and 11 of 14 by US (78.6%). In one of the 11 patients, not an immediate US but a follow-up on the next day revealed an injured organ. In 6 out of the 12 patients who underwent both plain and contrast enhancement (CE), CT, CE-CT demonstrated the injured organ more clearly than plain CT. US with sector probe was also useful for demonstrating the injured lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Injuries↗

PubMed1990

[The role of gallium-67 citrate scintigraphy in gastro-intestinal malignant lymphoma].

To evaluate the clinical usefulness of gallium-67 scintigraphy in the detection of the gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, gallium-67 scintigraphy was reviewed on 24 cases (25 lesions; stomach in 20, ileum in 2, and terminal ileum and/or cecum in 3). Twenty-three out of the 25 lesions (92.0%) were detected by gallium-67 scintigraphy, while barium study could detect all of the 25 lesions. The sizes of the gallium-67 negative 2 lesions were the smallest of all (2.5 and 3.0 cm). The tumor size was considered to the most important factor in the detection by gallium-67 scintigraphy, while the histological classification and the location of the tumor were not related to its detectability. Findings in follow-up gallium-67 scintigraphy after therapy on 10 cases were correlated well with the therapeutic effects. These data suggest that gallium-67 scintigraphy is useful for the detection of GI involvement of NHL and for the assessment of therapeutic effects.

Adult↗

PubMed1990

Modification of anoxic neuronal injury by human recombinant epidermal growth factor and its possible mechanism.

A primary culture of cortical neurons was established from a 17-day rat embryo. Twenty-four hours after plating, the culture medium was changed to a chemically defined one, and human recombinant EGF (rEGF) was added to the medium at concentrations of 1, 10, and 100 ng/ml. Anoxic stress was exerted on the cultured neurons for 4 hr. Without anoxia, rEGF at a concentration of 10 ng/ml supported neuronal survival. When rEGF was not present in the culture medium, anoxic stress reduced neuronal density to one-tenth that of the nonanoxic group. The rEGF improved neuronal recovery from anoxia significantly, with survival dependent on rEGF dosage. Monoclonal antibody for EGF receptors canceled the effect of rEGF on survival of neurons in a dose-dependent manner. Therefore, rEGF functioned to support neuronal survival from anoxia through EGF receptors. Ontogeny of the EGF receptors was detected immunocytochemically with anti-EGF receptor antibody. About 70% of the cultured neurons were stained by the anti-EGF receptor antibody 3 days after change of medium, and immunoreactivity for EGF receptors was found to be located on the soma of neurons. Binding activity of EGF receptors was detected 5 days after change of medium with receptor binding assay and Scatchard analysis. High-affinity binding sites were detected only in neurons cocultured with rEGF (10 ng/ml) for 5 days. The data indicate that rEGF in sufficient concentration induces high-affinity sites of the EGF receptor and that EGF may have an antianoxic effect through the EGF receptors.

Animals↗

PubMed1990

Ultrastructural investigation of the CA1 region of the hippocampus after transient cerebral ischemia in gerbils.

Ultrastructural damage leading to delayed neuronal death was investigated in the mid-CA1 region of the hippocampus from the stratum (str.) moleculare to oriens after transient bilateral forebrain ischemia in Mongolian gerbils. After ischemia for 5 min without recirculation, mild swelling of the peripheral part of the apical and basal dendrites was already apparent in the str. moleculare and str. oriens. Mitochondria in the dendrites were also swollen in the same area. During recirculation for 12 h to 3 days, swelling of the dendritic cytoplasm persisted with formation of microvacuoles, but swelling of mitochondria receded. Microvacuolation and loss of microtubules were also observed in the proximal part of the dendrites during this period, and swelling and disruption of internal cristae were observed in mitochondria after recirculation for 3 days. The dendrites became severely degenerated after recirculation for 4 days. In the pyramidal cell bodies, no abnormality was observed at the end of ischemia for 5 min, but disaggregation of polyribosomes and swelling of the endoplasmic reticulum were observed 12 h after recirculation. Proliferation of the endoplasmic reticulum in parallel arrays occurred after recirculation for 1 day and persisted. Severe degeneration of the pyramidal cell bodies was obvious after recirculation for 4 days. The findings observed in the present investigation suggested that the neuronal structure most vulnerable to ischemia was the peripheral part of the dendrites and postischemic neuronal damage occurred early in this part of the dendrites.

Animals↗

PubMed1990

Single photon emission computed tomography (SPECT) using N-isopropyl-p-(123I) iodoamphetamine (IMP) in the evaluation of patients with epileptic seizures.

To evaluate the clinical usefulness of IMP SPECT in the diagnosis of epilepsy, 6 normals and 52 patients in the interictal phase were studied. Thirty min after an intravenous injection of 111 MBq IMP, SPECT was performed using a rotating gamma camera. Of 21 patients with simple partial seizures, a localized decrease of uptake was shown in 16, and an increase in 3. Topologically, these findings corresponded well to the ictal symptoms. Nine of 13 patients with localized epileptic EEG had a good correspondence between the findings on EEG and IMP SPECT. In 20 of 23 with complex partial seizures, the coronal images showed laterality of uptake in the temporal lobes, whereas the CT was normal in 14. However, these findings on IMP SPECT agreed with the EEG in the temporal leads in only 5 cases. Of 8 patients with primary generalized seizures, a diffuse cerebral decrease was shown in 3 of 4 patients with convulsive seizures (grand mal), and a normal uptake in 3 of 4 patients with non-convulsive seizures (petit mal). However, 2 patients showed a localized decrease, therefore, we determined that they suffered from partial seizures evolving to secondarily generalization. From these data, we concluded that IMP SPECT could be a useful method in the diagnosis of epilepsy.

Adolescent↗

PubMed1990

T98G glioma cells have nicks in DNA in quiescent phase.

Human glioblastoma-derived cell line, T98G, is arrested in the G1 phase of the cell cycle when serum is deprived. Using this cell line, we investigated the relation between the cell cycle and DNA single-stranded breaks, "nicks," by an in situ nick-translation method. When T98G cells were cultured without serum for 60 h, many small cells with condensed chromatin and scanty cytoplasm appeared. These small cells that were immunohistochemically considered to be in the G0 or early G1 phase had many nicks in DNA. When serum was added, these small cells with nicks disappeared within 1 to 4 h. VP-16, a DNA topoisomerase II inhibitor, delayed the disappearance of these small cells with nicks. This indicated that the action of DNA topoisomerase II on the chromatin is required to repair nicks in T98G glioma cells and to promote the progression from the quiescent to the proliferating phase.

Antigens, Surface↗

PubMed1990

Hippocampal neurons become more vulnerable to glutamate after subcritical hypoxia: an in vitro study.

The neurotoxicity of glutamate and hypoxia was investigated in vitro on hippocampal neurons, which were obtained from 18-day-old rat fetuses and were maintained for 3 days in culture. Chemically defined medium without glutamate was used and the plating density was low enough that the effect of exogenously added glutamate could be directly evaluated. In the normal culture condition 1 mM glutamate was necessary to cause significant neuronal loss in the following 24 h. In marked contrast, when glutamate was added after subcritical hypoxic stress, a dose of glutamate as low as 10 microM could exhibit neurotoxicity. Administration of MK-801, a selective noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, could in part reverse this increased susceptibility to low-dose glutamate after hypoxia, although MK-801 could not protect hippocampal neurons from high-dose glutamate. Therefore, both the NMDA receptor and other subclasses of the glutamate receptor may be involved in this neurotoxicity of glutamate. Different mechanisms of glutamate neurotoxicity with high and low doses are discussed. Our results showed that hippocampal neurons exposed to subcritical hypoxia become more vulnerable to glutamate than those without hypoxia. This increased susceptibility is of great interest to understanding the mechanism of slowly ongoing neuronal loss caused by ischemia or epilepsy.

Animals↗

PubMed1990

Interleukin 2 receptor beta chain expressed in an oligodendroglioma line binds interleukin 2 and delivers growth signal.

Interleukin 2 (IL-2) is a potent growth factor for T lymphocytes, playing a crucial role in the immune response. In view of the considerable evidence that the immunoregulatory cytokines (or lymphokines) also play a role in the growth and differentiation of cells in the central nervous system (CNS), we examined the operation of the IL-2 system in a cell line of CNS origin by expressing a cDNA encoding the beta chain of the human IL-2 receptor (IL-2R beta, a 75-kDa protein). When the cDNA was expressed in a human oligodendroglioma cell line, ONS-21, the IL-2R beta bound IL-2 with an affinity similar to that in lymphoid cells (Kd, approximately 2 nM). Furthermore, cell proliferation ([3H]thymidine incorporation) was stimulated by IL-2. These results demonstrate that the same cytokine receptor is functional in cells of the immune system and CNS and point to a molecular mechanism that is similar for growth-signal transduction between lymphoid and neural cells but that may be different in other cells, such as fibroblasts.

Antibodies↗

PubMed1990

RNA synthesis and processing in the gerbil brain after transient hindbrain ischaemia.

Ribonucleic acid (RNA) synthesis was investigated in gerbils subjected to 15 min transient hindbrain ischaemia using [2-14C]uridine autoradiography. Distribution of synthesized RNA in the subcellular fraction of the tissue was detected by differential centrifugation and density gradient separation using Whittaker's method. In [2-14C]uridine autoradiography, uptake of the tracer into the RNA fraction was not reduced after transient ischaemia. Distributional analysis of [2-14C]uridine in the subcellular fractions revealed that tracer activity in the P3 (microsomes) fraction decreased in the ischaemic regions and tended to decrease in the P4 (ribosomes) fraction, although not significantly. Tracer activity in the P1 (nuclei and cell debris) and P2 (mitochondria, myelin and nerve ending particles) fractions did not decrease. These results indicate that RNA synthesis in the nuclei is not inhibited by ischaemia, but RNA processing is disturbed by the level of the transport. Modification of RNA synthesis and processing by transient ischaemia may influence protein synthesis.

Animals↗

PubMed1990

A method for computing the derivative of noisy time-activity curves and its application to radioisotope dynamic analysis.

A method for computing the slope or the derivative of time-activity curves containing statistical fluctuations is described. The algorithm presented employs digital differentiation as a digital filter. In designing an effective differentiating filter the Chebyshev-type min-max method and Remez exchange algorithm are used to minimise the weighted Chebyshev error. The validity of this method has been investigated using computer-based Monte Carlo simulation. Renogram curve analysis is presented as an example of an application of this method to radioisotope dynamic analysis. The ratio of the bilateral slopes of the renogram's second segments estimated using this method correlated well with the renal plasma flow ratio (r = 0.97, n = 16). The functional images of the slope of the renogram's second segments have been constructed and ascertained to be clinically useful. This method is considered to provide a powerful tool for extraction of quantitative information both in research and in routine nuclear medicine clinical work, and may be useful in various other fields.

Algorithms↗

PubMed1990

Neural transplantation in mouse Parkinson's disease.

A complete recovery from the methamphetamine-induced rotational response was shown in C57BL/6 (H-2b) mice which had had unilateral 6-OHDA lesions in the nigrostriatal pathway about 60 days after transplantation of approximately 1 x 10(6) dopamine-rich cells from syngeneic or allogeneic (C3H/HeN, H-2k) mouse embryos (ED 15), without immunosuppressive agents. Morphological examination showed tyrosine-hydroxylase-immunoreactive cell clusters around the needle tract in the mice which were transplanted not only with syngeneic cells but also with allogeneic cells. This might indicate that so-called immunosuppressive agents are not necessary for grafted embryonic cells to survive in an allogeneic mouse brain.

Animals↗

PubMed1990

Lipid metabolism in acromegalic patients before and after selective pituitary adenomectomy.

Lipid metabolism was studied in 16 acromegalic patients who all underwent transsphenoidal selective pituitary adenomectomy (SPA). Before the operation, their serum lipid levels correlated with none of the basal levels of serum growth hormone (GH), basal levels of plasma somatomedin-C (SM-C), fasting levels of plasma glucose (FPG), peak levels of plasma glucose (PGp) or basal and peak levels of serum immunoreactive insulin (IRIb and IRIp, resp.) in the oral glucose tolerance test (OGTT), and obesity indices. The serum GH levels as well as plasma SM-C levels in the group with decreased serum high density lipoprotein-cholesterol (HDL-C) differed greatly from those of the normal HDL-C group. However, there was no significant difference in either serum GH or plasma SM-C between groups with and without metabolic abnormality of any other lipid examined. After the operation, the basal levels of serum GH and plasma SM-C decreased significantly. In conjunction with these changes, PGp, serum IRIb, serum triglyceride (TG), non-esterified fatty acid (NEFA) and very low density lipoprotein (VLDL) decreased significantly. In contrast, serum HDL-C increased significantly. However, FPG, serum IRIp, obesity indices, serum total cholesterol (TC) and serum low density lipoprotein (LDL) showed no significant change. There were no significant differences in the levels of any serum lipid either before or after surgery among the diabetic, borderline and normal types defined by the preoperative OGTT patterns. Atherogenic indices (AIs) decreased significantly and returned to normal postoperatively. These results suggest that obesity or secondary diabetes is not a direct cause of hyperlipidemia in acromegaly. The prognosis of acromegaly is affected by arteriosclerotic complications. It is intriguing, therefore, that AIs were normalized by transsphenoidal SPA. Being rather a safe procedure, it can be performed without hesitation, aside from a conservative treatment.

Acromegaly↗

PubMed1990

Dolichoectatic basilar artery treated by reducing hemodynamic stress--report of two cases.

Two cases of dolichoectatic basilar artery with a mass effect to the brainstem structure were treated by reducing hemodynamic stress. In one case, angiograms showed the dolichoectatic basilar artery creating a turbulent flow in the vertebrobasilar junction, and unilateral vertebral artery clipping in addition to posterior fossa decompression was performed. The other case, a combination with bilateral internal carotid artery occlusion, underwent bilateral superficial temporal artery-middle cerebral artery anastomoses. The possible surgical treatments of dolichoectasia are discussed.

Adolescent↗

PubMed1990

[Expression of major histocompatibility complex on human medulloblastoma cells].

Medulloblastoma is one of the most common malignant brain tumors in childhood. These cells are immature bipotential cells that could differentiate into both neuronal and glial cells. The authors established two human medulloblastoma cell lines. One was derived from a 2-year-old girl with cerebellar tumor (designated as ONS-76) and another was from a 9-year-old girl with metastatic tumor in the right frontal lobe (ONS-81). Immunohistochemical studies showed that both cell lines possessed 145 and 200 kDa neurofilament proteins and neuron-specific enolase, without glial fibrillary acidic protein and S-100 protein. It was shown that interferon gamma could enhance or induce the expression of the major histocompatibility complex (MHC) antigens which play a major role in immune response. Also shown for the first time was the expression of MHC class II antigens on human medulloblastoma (ONS-76 and 81) with neuronal differentiation.

Cerebellar Neoplasms↗

PubMed1990

Partial callosotomy for Lennox-Gastaut syndrome--first cases in Japan.

Corpus callosotomy is a well established procedure for the treatment of intractable epilepsy. However, this is the first clinical report of surgical division of the corpus callosum in Japan. Four patients with refractory seizures suffering from Lennox-Gastaut syndrome underwent anterior partial corpus callosotomy. Their seizures consisted of absences, tonic, atonic, tonic-clonic attacks and were characterized by frequent falls. Electroencephalograms showed paroxysms of bilateral synchrony of slow spike and wave complexes. Postoperative follow-up during 12-27 months showed that partial callosotomy reduced the frequency and severity of seizures in all the patients, although they still require antiepileptic medication. This procedure was effective even in patients with mixed cerebral dominance and also in a patient with low intelligence quotient. Postoperatively, disconnection syndrome developed in three patients, which was transient in one and lasting in two.

Adult↗

PubMed1990

[Metastases to the brain--prognosis and surgical indications].

The prognosis of the patients with metastases to the brain is very poor. Based on the data obtained from the Brain Tumor Registry in Japan, relative survival rate curve of the cases with metastatic brain tumors is extremely similar to that of the cases with glioblastoma multiforme which is the most malignant primary brain tumor. Data obtained from the Department of Neurosurgery of Osaka University Medical School, the Center for Adult Diseases, Osaka demonstrated that the brain lesions were the direct causes of death only in 26% of the cancer patients with brain metastases. The result might have indicated that brain metastasis itself could be more controllable than the other lesions of systemic in most of the cases. The indications for surgical treatment of metastatic brain tumors are, in general, as follows; (1) the primary cancer is cured or to be cured, (2) no metastasis to other organs, (3) the brain metastasis is single, solitary and surgically accessible, and (4) the general condition is good enough. But recent advancement in the diagnosis, surgery and patient care are going to extend the indications for surgical treatment. Surgical mortality becomes less than a few percent. The changes of performance status by surgery were investigated in the patients treated in Department of Neurosurgery, Osaka University Medical School and the Center for Adult Diseases, Osaka. Improvement of the performance status after surgery was obtained in 57.8%, stationary in 30.5%, and worsening only in 11.8%.

Brain Neoplasms↗