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Biomedical subjects

H Sasajima

Publications and source records attributed to H Sasajima.

28 records · Page 2Linked to original sources
PubMed1994

Vascular malformations of the brain in hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease).

Six patients with vascular malformation of the brain in hereditary hemorrhagic telangiectasia (HHT) were reviewed to determine clinical and radiographic characteristics of these lesions. There were two patients with arteriovenous fistula (AVF), three with arteriovenous malformation (AVM), and one with multiple AVMs associated with AVF. Seizures were the most common presenting symptom (seen in three patients), and two of them had intracerebral hematomas (ICH). In the remainder, the malformations were incidentally found in the course of evaluation of other diseases. Their locations were variable, but the majority was superficially confined to the cerebral cortex. Arterial supply was from mostly one feeding artery that was a cortical branch of either anterior, middle, or posterior cerebral artery. In six of nine malformations, the venous drainage was through a superficial cerebral vein into either the superior sagittal sinus or transverse sinus. Direct surgery was done on two patients with ICH, artificial embolization on one, and stereotactic radiosurgery on one. The cerebral vascular malformations in HHT are not infrequent, and in particular the importance of computed tomography and cerebral angiography should be recognized in patients with pulmonary AVF associated with HHT.

Adolescent↗
PubMed1991

[A study on the incidences of streptococcal infectious diseases in the regional surveillance informations of infectious diseases in Japan (2nd report)].

The incidences of streptococcal infectious diseases in the regional surveillance informations of infectious diseases of 47 prefectures were compared with each other by the ratios of number of patients with streptococcal infectious diseases, exanthema subitum and varicella to the populations of surveyed age groups, respectively. It was estimated that although there were almost no regional differences in the ratios of exanthema subitum and varicella, the ratios of streptococcal infectious diseases were high in Hokkaido, Akita, Yamanashi, Shiga and Ehime Prefectures, respectively, and was low in Okinawa Prefecture. The corrected incidences of number of patients with streptococcal infectious diseases, calculated on the basis of the ratios of exanthema subitum and/or varicella, were also high in the regions of Hokkaido, Akita, Iwate, Nagano, Yamanashi, Gifu, Shiga, Okayama and Ehime Prefectures, respectively, and were low in the regions along the Pacific from the southern Tohoku (northern Japan) through a part of the Shikoku Island and the Sea of Japan from the Hokuriku (central Japan) through the Kyushu Island, and the regions of Nara and Okinawa Prefectures, respectively. The climate in the regions with high corrected incidence belonged to the Tohoku-Hokkaido, the Central Highlands and the Seto Inland Sea types, respectively. On the other hand, the regions with low corrected incidence belonged to the Tokai-Kanto, the Nankai (southern sea of Japan), the Hokuriku-Sanin, the Kyushu and the Okinawa climate types, respectively.

Anti-Bacterial Agents↗
PubMed1990

[Ventriculoperitoneal shunts with the use of pressure-adjustable valve in the management of hydrocephalus].

Sixteen patients with hydrocephalus of varied etiology who underwent ventriculo-peritoneal shunts utilizing pressure-adjustable valves were reviewed, and the usefulness of the pressure-adjustable valve in the management of hydrocephalus was evaluated. Before shunting all patients had CT evidence of hydrocephalus with Evans' Index greater than 30%. High-, medium- and low-pressure settings were chosen in 3, 11 and 2 patients respectively, according to the CSF pressure as measured during lumber puncture or ventricular drainage. Following the shunting procedures with programmable pressure valves, hydrocephalus was alleviated with Evans' Index being 27% on the average, as evaluated by CT scans. Such clinical symptoms as disturbed consciousness, dementia and increased intracranial pressure all subsided. There were no mortality, infection or revision during the follow-up period of 5 to 16 months. Of particular note was that, among these 16 cases, there were three illustrative cases in which programmable pressure valves were found useful in coping with newly developed subdural effusion and low-intracranial-pressure syndrome, by manually adjusting the valves to higher pressure settings.

Adult↗
PubMed1989

[Chemotherapeutic strategy in rat brain tumor cells resistant to ACNU using an in vitro colony formation assay].

Nitrosourea compounds have been widely used in the chemotherapy of malignant brain tumors, because of their blood-brain barrier permeability. However, drug resistance to nitrosoureas has been recently a major concern. Using an in vitro colony formation assay, intrinsic and acquired resistances to an anticancer nitrosourea, 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), were analyzed in rat 9L and C6 glioma cells. 9L and C6 cells were treated with varying doses of ACNU for 2 hours. Ten days after, the cells were fixed and stained with crystal violet. Colonies consisting more than 50 cells were counted. The survival fraction following treatment is the ratios of colony efficiency of treated cells to the colony efficiency of untreated control cells. The dose-response curve for ACNU indicated the existence of a shoulder (Dq, quasithreshold dose) at doses and an exponential cell-killing at higher doses with D0(37% survival dose). Based on dose-response curves corresponding to multitarget single-hit model, 9L cells showed 7.4 microM, 2.9 microM, and 14 microM at Dq, D0, and SD10 (10% survival dose) values, respectively, whereas C6 cells showed respective values of 6.4 microM, 30 microM, and 75 microM. 9L cells had significantly less intrinsic resistance to ACNU than C6 cells at the p less than 0.005 level by a covariance analysis of the curves. As with changes of drug susceptibility after ACNU treatment, both parent cells were treated every other day (1, 5, and 10 repeated times) with various doses up to approximately 1% survival dose of the parent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Circumvention of ACNU-resistance in rat glioma cells by pretreatment with O6-methylguanine].

The chemotherapy of malignant brain tumors has been, only partially successful yet. Recently major concern is drug resistance, one of possible mechanisms of such drug resistance stems from inducible repair enzyme, especially in case of chloroethylnitrosoureas as ACNU or BCNU. We examined the changes of acquired resistance to ACNU in rat glioma cells by pretreatment with O6-methylguanine, which is a substrate for O6-methylguanine methyltransferase. ACNU-resistant (9L/AC) cells had established after 10 times treatments of ACNU. 9L/AC cells were pretreated with 2 mM O6-methylguanine for 2 hours, and subsequently challenged with increasing doses of ACNU for 2 hours. In vitro colony formation assay the survival fraction of 9L and 9L/AC cells ranged from 0.39 to 0.63 by 2-hour reaction of 1-3 mM O6-methylguanine. Based on the dose-response curve for ACNU in 9L/AC cells, by O6-methylguanine pretreatment (2 mM), ACNU-resistance decreased markedly to one-third, one-fifth, and one-two hundredth at 12, 24, 36 microM ACNU, respectively. In contrast, the survival of 9L cells against ACNU was similar under O6-methylguanine pretreatment or nontreatment condition. Therefore, ACNU-resistance is considerably related to DNA repair enzyme induction, and the substrates may potentiate the cell-killing effect of ACNU in the resistant glioma cells.

Animals↗
PubMed1988

[Analysis of DNA damage induced by nitrosourea derivatives in rat brain tumor cells using a sequencing procedure].

DNA damages caused by various anticancer nitrosourea compounds such as ACNU and MCNU were studied. Reiterated fragments of 167 and 203 base pairs (bp) were obtained after Hind III and Hae III restriction endonuclease digestion of 9L rat brain tumor DNA. The end-labeled reiterated fragments were reacted with ACNU and MCNU, which resulted in the scission breaks corresponding to the locations of guanine on an extended Maxam-Gilbert sequencing gel. Subsequent piperidine hydrolysis yielded scission products more frequently. These results indicate that nitrosoureas such as ACNU and MCNU generate DNA scission breaks and/or alkali-labile sites preferentially at the position of guanine moieties in rat brain tumor DNA.

Animals↗
PubMedDate not supplied

Preliminary results with technetium-99m MIBI SPECT imaging in patients with brain tumors: correlation with histological and neuroradiological diagnoses and therapeutic response.

SPECT using Tc-99m MIBI was performed in patients with brain tumors in order to determine Tc-99m MIBI uptake in brain tumors and to evaluate the efficacy of MIBI imaging in the assessment of treatment response. A MIBI uptake index was calculated on SPECT imaging. All tumors with a MIBI-index higher than 7.5 were malignant. In the tumors evaluated before and after radiochemotherapy, the MIBI-index immediately following therapy correlated with treatment response 2 months after therapy. Thus, semiquantitative assessment using Tc-99m MIBI SPECT imaging may be useful in the evaluation of treatment response.

Adolescent↗