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Biomedical subjects

M Jimbo

Publications and source records attributed to M Jimbo.

At least 19 recordsLinked to original sources
PubMed1992

Radiation-induced edema after radiosurgery for pontine arteriovenous malformation. A case report and detection by magnetic resonance imaging.

A 29-year-old woman, who had undergone stereotactic radiosurgery for a pontine arteriovenous malformation, experienced sudden onset of facial nerve palsy with trigeminal nerve disturbance 19 months after irradiation. Magnetic resonance imaging revealed significant radiation-induced edema surrounding the nidus. Angiography demonstrated total obliteration of the arteriovenous malformation 24 months after irradiation. Further magnetic resonance imaging studies, performed 28 months after treatment, showed that, despite the persistence of symptoms, the radiation-induced edema had subsided.

Adult↗
PubMed1992

Long-term follow-up of radiosurgically treated arteriovenous malformations in children: report of nine cases.

Long-term follow-up results of nine children treated for cerebral arteriovenous malformation with a gamma unit are presented. Complete nidus obliteration was angiographically confirmed in six cases and significant decreases in arteriovenous malformation size were observed in the other three. There were no radiation-related deteriorations in physical or mental development. In seven patients who underwent endocrinological examination more than 3 years after irradiation, five were normal and the other two showed only low serum adrenocorticotropic hormone levels, which, however, did not necessitate replacement therapy. Neurodiagnostic imaging follow-up studies revealed no radiation-induced lesions in any of the nine cases.

Adolescent↗
PubMed1992

Long-term results of radiosurgery for arteriovenous malformation: neurodiagnostic imaging and histological studies of angiographically confirmed nidus obliteration.

Detailed follow-up results for 25 patients treated for cerebral arteriovenous malformation (AVM) with a gamma unit are presented. Complete nidus obliteration was angiographically confirmed in 16 (73%) of 22 cases receiving full-dose irradiation. There were no radiation- or AVM-related mortalities. However, we did experience one case of radiation-related morbidity and one of angiography-related mortality, the autopsy findings of which are discussed. Computed tomography scan and magnetic resonance imaging follow-up studies of radiosurgically treated AVMs indicated that increased enhancement of the nidus after contrast or gadolinium administration could persist even after obliteration of the AVM was angiographically confirmed.

Adolescent↗
PubMed1992

Improved inhibitors of glucosylceramide synthase.

An inhibitor of glucosylceramide (GlcCer) synthase, 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), has been reported to deplete cells and mice of their glucosphingolipids. This inhibitor has proved useful for the elucidation of the many functions of this lipid family [reviewed by Radin, N.S. & Inokuchi, J. (1991) Trends Glycosci. Glycotechnol. 3, 200-213]. In the present study, we have synthesized homologs of PDMP having different acyl chains (C6-C18) and compared their effectiveness for the inhibition of GlcCer synthase in vitro and their inhibition of GlcCer, protein, and DNA synthesis in cultured MDCK (Madin-Darby canine kidney) cells. Using MDCK homogenates and mouse brain and liver microsomes, we found that the C6 compound was relatively inactive and that the longer chain compounds did not differ much in inhibitory power. However, the use of intact MDCK cells showed that the longer chain homologs were much more effective in inhibiting GlcCer synthesis, cell growth, and incorporation of [3H]thymidine. Tests with two radioactive homologs showed that the inhibitor with a longer acyl chain was taken up much more effectively by MDCK cells and that this difference explains the much greater effectiveness of this homolog in intact cells. The inhibitors were effective when solubilized either with a nonionic detergent or with bovine serum albumin. The extent of decrease in DNA synthesis was not directly proportional to the decrease in cellular glucosylceramide, possibly because only a low level of the glycolipid is needed for DNA synthesis.

Animals↗
PubMed1992

Effects of antihypertensive agents on arterial baroreceptor reflexes in conscious rats.

The effects of antihypertensive treatment with four currently used agents (trichlormethiazide, atenolol, nicardipine, and enalapril) on the arterial baroreceptor reflex control of renal sympathetic nerve activity and heart rate were investigated in 45 conscious spontaneously hypertensive rats and 37 age-matched Wistar-Kyoto rats. Antihypertensive agents were administered for 2 weeks beginning at 8 weeks of age to treat and prevent the development of hypertension. Blood pressure was reduced to a similar level (-13 +/- 3 mm Hg, p < 0.05) by each antihypertensive agent. Blood pressure, heart rate, and renal sympathetic nerve activity were recorded in the conscious state during phenylephrine and nitroglycerin ramp infusion. The gain in the baroreceptor reflex was determined from the maximum slope of logistic function curves. Untreated spontaneously hypertensive rats exhibited decreased sensitivity of reflex control of renal sympathetic nerve activity and heart rate (-1.78 +/- 0.07% of control/mm Hg and -2.16 +/- 0.05 beats per minute/mm Hg, respectively) compared with untreated Wistar-Kyoto rats (-3.62 +/- 0.18% of control/mm Hg, p < 0.01, and -3.46 +/- 0.11 beats per minute/mm Hg, p < 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Peritumoral brain edema associated with meningioma--histological study of the tumor margin and surrounding brain.

Thirty-nine cases of intracranial meningiomas were analyzed to identify factors causing brain edema. Edema was significantly correlated with tumor size and the destruction of the leptomeninges and cortex. Meningotheliomatous meningioma tended to have more peritumoral edema. There was no correlation between the presence of edema and location of the tumor or histological features including lymphocytic infiltration and the presence of glial fibrillary acidic protein-positive cells in the tumor tissue. Larger tumors destroy the leptomeninges and cerebral cortex, allowing direct transmission of humoral edema-promoting factor or edema fluid into the white matter, resulting in vasogenic edema.

Adolescent↗
PubMed1992

Postoperative neurosurgical infection and antibiotic prophylaxis.

The most suitable antibiotics for chemoprophylaxis in neurosurgery and risk factors for postoperative neurosurgical infection were investigated by retrospective analysis of 807 neurosurgical procedures in 566 patients between 1980 and 1989. Prophylactic antibiotics were administered intravenously for 6 or 7 postoperative days in all instances. The 807 operations were classified according to the antibiotics used into: 1) penicillin, 2) cephem-I, 3) cephem-II, 4) cephem-III, and 5) others. Postoperative neurosurgical infections occurred in 27 of 807 operations (3.3%), or 27 of 566 patients (4.8%). Hypertension and surgery performed in summer carried a significantly higher risk of infection. Diabetes mellitus, steroid administration, prolonged surgery, re-exploration, and surgery for hemorrhagic cerebrovascular diseases were associated with increased risk, but were not statistically significant. Infection rates by type of chemoprophylaxis were: 3.6% in the penicillin group, 3.7% in the cephem-I group, 1.7% in the cephem-II group, 5.7% in the cephem-III group, and 2.8% in the others group. This result indicates that the best choice for prophylactic antibiotic therapy may be a second-generation cephem.

Adolescent↗
PubMed1991

Sphingosine inhibits attachment of murine Lewis lung carcinoma cells to laminin and type IV collagen.

The effect of sphingosine (SPH) on the adhesive properties of Lewis lung carcinoma (3LL) cells was investigated using plastic precoated with the extracellular matrix proteins, laminin, fibronectin, or type IV collagen. Treatment of 3LL cells with SPH (0.5-10 microM) resulted in a dose-dependent decrease in the ability to bind to laminin and type IV collagen but had little or no effect on attachment to fibronectin. Phorbol 12-myristate 13-acetate (PMA) selectively enhanced attachment of 3LL cells to laminin and collagen. The inhibitory effect of SPH on attachment to both proteins was competitively antagonized by PMA. These results suggest that SPH acts as a negative effector for cell attachment to laminin and collagen, and that the cell attachment process to both proteins might be regulated in part by protein kinase C.

Animals↗
PubMed1990

Inhibition of experimental metastasis of murine Lewis lung carcinoma by an inhibitor of glucosylceramide synthase and its possible mechanism of action.

In view of the increasing evidence that glucosphingolipids (GSLs) on tumor cell surfaces play an important role in tumor metastasis, an inhibitor of glucosylceramide synthase, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) was used to evaluate the role of GSLs in this respect. Treatment of Lewis lung carcinoma cells with 5 microM D-PDMP resulted in a time-dependent marked decrease in levels of all cellular GSLs (glucosylceramide, lactosylceramide, ceramide trihexoside, globoside, and ganglioside GM3). By 6 days, the total GSL content was reduced to approximately 20% of the level in the untreated control cells and at the same time the lung-colonizing capacity of the PDMP-treated cells in inoculated mice was greatly reduced. Closely associated with the degree of GSL depletion, the ability of the cells to invade reconstituted basement membranes in vitro was also reduced, suggesting that GSLs in tumor cell membranes modulate the cell surface interaction with basement membrane components. In order to assess a possible contribution of the defective capacities to drug-induced suppression of experimental metastasis and invasion, we tested the effect of D-PDMP on attachment and migration to laminin and fibronectin and found that the inhibitor specifically reduced the laminin-mediated attachment and migration, whereas it had no effect on fibronectin-mediated attachment and migration. These effects of the inhibitor on lung colonizing capacity in vivo and the invasion, adhesion, and migration properties of the cells in vitro were reversible within 24 h after removal of the drug. By contrast, L-PDMP (the enantiomeric form of D-PDMP), which has no inhibitory activity on glucosylceramide synthesis, did not cause any of the changes produced by D-PDMP. Together, these results suggest that GSLs in tumor cell membranes are essential for the metastatic spread of tumor cells through basement membranes, modulating the interaction of laminin and its receptors.

Animals↗
PubMed1988

[Microtumor presenting with temporal lobe epilepsy--a case report].

A 15-year-old girl was admitted to our clinic on July 16, 1985 with the epilepsy which had been resistant to various anticonvulsant therapies. At the age of 10 years automatism seizure, characterized by purposeless movement of arms and head of which the patient was unaware, began to occur and became as frequent as two to three times each day. From the age of 13 years, there were also grand mal seizures several times a year in spite of medical treatment. She had normal delivery and no history of febrile convulsion. There was no family history of epilepsy or mental disease. When examined on admission, she had normal personality and intelligence. There was no neurological abnormality. She complained of sleepiness and hirsutiness. Fit of automatism occurred two to three times a day during admission, though the blood levels of anticonvulsant drugs such as phenobarbital, phenytoin and carbamazepine reached to therapeutic concentration. EEG examination including infratemporal lead recording showed right temporal spike focus. But all the neuroradiological studies such as skull X-rays, CT, cerebral angiography and magnetic resonance imaging failed to show abnormal finding. Right temporal lobectomy was carried out under general anesthesia on Aug 22, 1985, and anterior two-thirds of the middle and the inferior temporal gyri were resected deeply to anterior hippocampus. To the naked eye, no abnormal finding was noted during the operation. In the surgical specimen, macroscopically nothing abnormal was found. Microscopically, serial sections of the lobe revealed clusters of oligodendroglial cells in cortical to subcortical region of the medial basal part of the temporal lobe.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Trochlear neurinoma.

A case of neurinoma of the trochlear nerve presenting with the sudden onset of headache followed by transient paresis of the right trochlear nerve in a 37-year-old woman is reported. Unique clinical manifestations of the tumor are discussed with a brief review of five cases reported in the literature.

Adult↗