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Biomedical subjects

H Handa

Publications and source records attributed to H Handa.

At least 361 records · Page 20Linked to original sources
PubMed1985

[Effects of phenobarbital on EEG and sensory evoked potentials in normal cat brain].

In adult cats, authors studied changes in parameters obtained by the recordings of sensory evoked potentials following cumulative intravenous administration of phenobarbital. P1 and N1 of cortical SEP showed gradual tendencies to decrease in amplitude and to increase in latency with increasing barbiturate dose. These changes preceded to the appearance of burst-suppression activity on electroencephalogram. At this point I-II and III-IV interpeak latencies of BAEP showed statistically significant increase. BAEP and all early components of SEP (I.II.III) persisted in the extremely high serum concentration of phenobarbital. Furthermore, II-III interpeak latency of BAEP showed no statistically significant increase. These experimental results suggest that sensory evoked potentials will provide useful information in the assessment of the brainstem function in patients under deep coma.

Animals↗
PubMed1985

[Clinical analysis of large and/or invasive pituitary adenomas].

To establish a more reasonable therapeutic guide line for large and/or invasive pituitary adenomas, 257 cases of pituitary adenoma were analyzed. Among 83 cases with slight or moderate suprasellar extension (Wilson's Grade II-A & B) in the pre-CT era, 57 patients were alive at the time of follow-up (mean follow-up period: 12.7 years). Death of unspecified causes other than cancer, myocardial infarction, etc. were reported in nine patients. Among 60 cases of Grade II-A & B in the post-CT era, 59 patients were alive (mean follow-up: 3.4 years). Comparing these groups, cases with huge suprasellar extension (Grade C) had much worse prognosis. Only two patients were alive among 14 cases of Group C in the pre-CT era. Seven cases of death with unspecified causes were reported. In the 13 cases of Group C in the post-CT era, 12 patients were alive but at least four of them were severely handicapped. In 10 cases with sphenoid invasion (Grade IV) in the pre-CT era, only two were alive. In the group of Grade IV in the post-CT era, one patient died and three patients were operated repeatedly. Severe complications of irradiation therapy occurred in seven patients (mean interval: 6.6 years) among 120 cases of irradiated pituitary adenomas in every category. Among six cases with histological malignancy, three were operated repeatedly; among the latter group, two patients died and the third showed intracranial metastases. The present data indicate that large and/or invasive pituitary adenomas have a pessimistic prognosis, although adenomas with mild or moderate simple suprasellar extension have fairly good prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1984

New small-caliber antithrombotic vascular prosthesis: experimental study.

Vascular prostheses with the inner diameter smaller than 1 mm were implanted to the common carotid artery of rats, and their patency was examined. Four types of tubes were prepared for this purpose in Experiment 1: polyethylene (PE), poly-(acrylic acid)-grafted polyethylene (PE-AA), polyacrylamide-grafted polyethylene (PE-AAm), and poly(vinyl alcohol) (PVA) tubes. Comparative studies made using nonsuture anastomosis revealed that the PE-AAm and PVA tubes were antithrombotic, although disconnection was noted at the anastomotic sites within 1 week and 1 month, respectively. Thereafter in Experiment 2, the PVA tubes were implanted to the common carotid artery of 20 rats using conventional anastomosis. Neither anticoagulants nor fibrinolytic agents were used in both series of experiments. Patency of the PVA tubes was 80% after 1 week and 70% after 1 month. In patent cases after 1 month, the luminal surfaces of the prostheses and the host arteries were examined using scanning electron microscopy. The lumen of the arteries and anastomotic sites was covered with endothelial cells, while the lumen of the PVA tubes was free from thrombi and there was no neointima formation. So far, there has been reported no manmade material that has completely antithrombotic property in vivo. However, our studies disclosed that PVA is antithrombotic and one of the most promising materials for the inner surface of small vascular prostheses.

Acrylic Resins↗
PubMed1984

Evidence for alpha 2 adrenergic receptors in bovine cerebral arteries.

Specific [3H]yohimbine binding to the homogenates of bovine cerebral arteries was saturable and of high affinity (KD = 21 nM) with a Bmax of 720 fmol/mg protein. On the other hand, there was no detectable specific [3H]prazosin binding to these tissues. Scatchard and Hill plot analyses of specific [3H]yohimbine binding indicated one class of binding sites. Specific binding of [3H]yohimbine was displaced effectively by alpha 2 adrenergic agents and less effectively by alpha 1 adrenergic agents. IC50 values for adrenergic drugs of [3H]yohimbine binding were as follows: yohimbine, 55 nM; tramazoline, 270 nM; clonidine, 580 nM; methoxamine, 15 microM; prazosin, 47 microM, phenylephrine, 49 microM; norepinephrine, 60 microM; epinephrine, 150 microM. These results suggest that alpha adrenergic receptors in bovine cerebral artery are mostly of the alpha 2 subtype.

Animals↗
PubMed1984

Single agent therapy of interferon for brain tumours: correlation between natural killer activity and clinical course.

The anti-tumour effect of mouse interferon (IFN) on an intracranially transplanted 203-glioma in C 57BL mice and the natural killer (NK) activity of spleen cells were studied. As a clinical trial, five patients with glioblastomas were treated with human fibroblast IFN and the anti-tumour effect of IFN and the NK activity of peripheral blood lymphocytes were also studied. The NK activity increased after the beginning of IFN therapy but there was no remarkable anti-tumour effect of IFN in both mouse and human studies. There was no marked correlation between the increased NK activity and the anti-tumour effect of IFN in this study.

Adult↗
PubMed1984

Treatment of malignant brain tumours with ACNU and phenobarbital: continuous infusion of ACNU into internal carotid artery and systemic administration of phenobarbital.

Thirteen patients with malignant brain tumours were treated by continuous intra-carotid infusion of ACNU in combination with systemic administration of phenobarbital. This aimed to maintain an ACNU concentration around the tumour cells higher for a relatively longer period and to make an ACNU concentration in the systemic circulation lower. Improvements on clinical states and CT findings were observed in 10 patients. The protective effect of phenobarbital against bone marrow suppression by ACNU was also suggested in this study. No complications were experienced in this treatment. This results strongly suggested that this technique is useful to treat patients with malignant brain tumours.

Adult↗
PubMed1984

STA-MCA anastomosis in patients with skull base tumours involving the internal carotid artery--haemodynamic assessment by ultrasonic Doppler flowmeter.

The role of superficial temporal artery--middle cerebral artery (STA-MCA) anastomosis was investigated with an ultrasonic Doppler flowmeter in 3 patients with sphenoid ridge meningiomas and one with a parasellar malignant teratoma, all of which involved the intracranial internal carotid artery. The intraoperative Doppler flow study revealed a remarkable increase in flow volume of the STA after trial occlusion of the middle cerebral artery in one case and permanent occlusion in two cases. These results substantiate the effectiveness of STA-MCA anastomosis. We also discuss surgical and other contrivances for obtaining sufficient blood supply from this bypass to prevent cerebral ischaemia in the acute phase after elective or accidental occlusion of a major cerebral artery. This is the first report of STA-MCA anastomosis in cases with brain tumour.

Carotid Artery Diseases↗
PubMed1984

Specific adoptive immunotherapy of malignant glioma with long-term cytotoxic T lymphocyte line expanded in T-cell growth factor. Experimental study and future prospects.

The purposes of the current study were: (1) to investigate the immunoregulatory effects of T-cell growth factor (TCGF) on the activation and differentiation of syngeneic cytotoxic T lymphocyte (CTL) populations generated against a 20-methylcholanthrene-induced ependymoblastoma, 203-glioma, in C57BL/6 mice; and (2) to determine whether the glioma-specific CTL clone (G-CTLL) could be established by TCGF, and whether the in vivo efficacy of the cloned cells could be rendered more effective in adoptive therapy. It was found that TCGF largely allows the CTL populations to proliferate and thus can activate the depressed cytotoxic activity in tumour-bearing mice. Two lines of G-CTLL were successfully obtained by the limiting dilution technique. The G-CTLL retained a TCGF-dependent proliferative growth and a marked cytotoxic activity with target specificity for over 18 months, characterized by a surface phenotype of Lyt-1-.2.3+, Lyt-2 antibody blocking of cytotoxicity and the production of immune interferon in response to mitogen and tumour antigen. In the Winn assay and the adoptive transfer assay, the therapeutic effects were detected in intracranially inoculated tumours in mice. The in vivo efficacy was dependent on the dose of G-CTLL and on the time of the intravenous administration, although the transfer was inversely ineffective in conditions of increased intracranial pressure. The mechanism responsible for the in vivo effect was probably due to the adoptive immunity and/or the tumour-specific interferon production of G-CTLL.

Animals↗
PubMed1984

Nd-YAG laser as a surgical tool.

As neurological operation has necessitated effective haemostatic devices, CO2 and Nd-YAG lasers have been introduced in this field. The CO2 laser was first studied and used in neurological surgery and many problems, such as safety, mobility, and others, were overcome by pioneers. The Nd-YAG laser has been developed mainly for endoscopic surgery. However, we noticed its strong haemostatic effect, used it in neurosurgery and found it to be quite effective in removing tumours. The following properties of the Nd-YAG laser are especially fitted for neurosurgical surgery: the laser beam is conducted through a light, thin and flexible quartz fibre; penetration of the laser beam into tissues is controlled by the output wattage, and the grade of coagulation is controlled by duration of irradiation time and by the output wattage.

Brain Neoplasms↗
PubMed1984

Extent of thermal penetration of Nd-YAG laser--histological considerations.

The extent of thermal penetration of Nd-YAG laser was studied histologically. The material was obtained from seven cases of various types of intracranial and extracranial tumours and normal temporal muscle obtained at operation. After irradiation of the tumour surface with the laser, the tumours were removed and depth and width of pathological changes caused by heat were studied. Histologically, materials consisted of a vaporized surface, carbonized, vesicular, necrotic, oedematous layer and surrounding intact brain tumour tissue. There was a direct relationship between the thermal effect and the irradiated thermal energy (watt x exposure time x pulse number). The results showed that the thermal effect was limited to a depth of 6 to 10 mm from the irradiated surface when irradiated 4 times at the power of 90 watts for 2 seconds.

Adult↗
PubMed1984

Location of intracranial aneurysms associated with cerebral arteriovenous malformation: statistical analysis.

Distributions of cerebral aneurysms by site were compared statistically in 78 reported cases associated with arteriovenous malformation, including our five cases, and cases with solitary intracranial aneurysms without arteriovenous malformation. When the feeder of an arteriovenous malformation was one of the branches of anterior, middle, or posterior cerebral arteries, the aneurysms were located on these respective arteries much more frequently than expected in the general aneurysmal population. This was statistically significant. Our results strongly suggest that abnormal hemodynamic stresses on the arteries from which the feeders branch out to arteriovenous malformations play a significant role in the development of intracranial aneurysms on these arteries.

Adult↗
PubMed1984

Suprasellar germinoma occurring two years after total removal of pineal teratoma.

A rare case of a suprasellar germinoma occurring 2 years after total removal of a pineal benign teratoma is presented. The suprasellar germinoma was not considered a recurrence or dissemination from the pineal tumor, but to have been transformed from germ cells present in the suprasellar region. Although it is controversial whether radiation treatment should be given to a patient with a totally removed benign teratoma, careful follow-up computed tomography scans are indispensable for detecting a possible occurrence of other germ cell tumors.

Brain Neoplasms↗
PubMed1984

Acromegaly with multiple secreting pituitary adenomas.

A case of acromegaly with two separate growth hormone-secreting pituitary adenomas is presented. The multiplicity was suspected on computerized tomographic scan and confirmed at transsphenoidal surgery. Possible occurrence of multiple adenomas is discussed.

Acromegaly↗
PubMed1984

Microheterogeneity of brain dopamine in the experimental acute cerebral ischaemia.

In order to reveal the correlation of energy failure and neurotransmitter metabolism in the acute stage of incomplete cerebral ischaemia, the change of NADH (reduced form of nicotinamide adenine dinucleotide) and brain dopamine was studied histochemically using the same specimen on the unilateral carotid ligation of mongolian gerbils. The severity of clinical symptoms was well correlated with the extent and intensity of NADH fluorescence. Dopamine in the caudate nucleus on the ligated side decreased heterogeneously shortly after the cerebral ischaemia. Preservation of dopamine was noted around the small vessels with thick walls. Thus, heterogeneity of dopamine decrease appears to be closely related to the structure of microvasculature. It was seen in areas of heterogeneously increased NADH, but also in areas of its homogeneous increase within 5 to 60 min after carotid ligation. This microheterogeneity of brain dopamine may be due to the difference of perfusion pressure at the microcirculation in the acute stage of incomplete cerebral ischaemia.

Animals↗
PubMed1984

Purification and characterization of rat low molecular weight kininogen.

Low molecular weight (LMW) kininogen was isolated from pooled rat plasma by chromatography on DEAE-Sephadex A-50, CM-Sephadex C-50, Blue-Sepharose CL-6B, and Sephadex G-100. It was shown to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoelectrophoresis. The molecular weight of rat LMW kininogen was determined to be 72,000 by SDS-PAGE. The LMW kininogen contained 83.5% protein, 4.0% hexose, 5.5% hexosamine, and 2.7% sialic acid. Kinin liberated from LMW kininogen by trypsin treatment was identified as an Ile-Ser-bradykinin(T-kinin) by analysis involving ion exchange column chromatography on CM-Sephadex C-25 and high performance liquid chromatography on a reverse-phase column (ODS-120T). LMW kininogen formed kinin with rat submaxillary gland kallikrein, but the kinin liberated was only 14% of the total kinin content, that is, that released by trypsin. In order to determine the immunochemical properties of LMW kininogen, specific antiserum was prepared in rabbits. The antiserum cross-reacted with high molecular weight (HMW) kininogen, but spur formation was observed between the LMW and HMW kininogens. The kininogen level in rat plasma was estimated to be 433 microgram/ml by a quantitative single radial immunodiffusion test.

Animals↗
PubMed1984

Requirement for distal upstream sequences for maximal transcription in vitro of early region IV of adenovirus.

A series of deletion mutants spanning the adenovirus early region IV (EIV) promoter were tested for transcription activity in vitro. At least three elements were found to be important for maximal transcription in HeLa whole-cell extracts. Deletion of the TATA box drastically reduced the transcription activity from the EIV promoter. Sequences between nucleotides -58 and -44 are also important for efficient transcription since deletion of this region reduced activity by 50%. More importantly, sequences residing upstream from -140 critically influence the level of EIV transcription. Deletion of sequences between nucleotides -325 (the right terminus of adenovirus genome) and -140 reduced the level of transcription more than 10-fold. It is possible that a specific cellular factor stimulates EIV transcription by recognition of these upstream sequences. The dependence of transcription from the EIV promoter on a distal upstream element may explain some aspects of the regulation of this promoter.

Adenoviruses, Human↗