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Biomedical subjects

T Andoh

Publications and source records attributed to T Andoh.

At least 199 records · Page 11Linked to original sources
PubMed1990

Effects of continuous negative extrathoracic pressure ventilation on renal function and alpha-atrial natriuretic peptide in normal individuals.

Continuous negative extrathoracic pressure ventilation (CNETPV) may induce atrial distention by augmenting venous return, resulting in the increased secretion of atrial natriuretic peptide (ANP) and natriuresis. To clarify this hypothesis, we investigated the effect of CNETPV on renal function and plasma ANP level. Nine male healthy volunteers were studied during three successive 60-minute periods under (1) spontaneous breathing, (2) CNETPV with continuous negative extrathoracic pressure of -10 cm H2O, and (3) spontaneous breathing again. Continuous negative extrathoracic pressure ventilation induced a transient increase in plasma ANP level, but changes in plasma ANP level were not statistically significant. Although there was no significant difference in urine volume and urinary sodium excretion among three successive periods, a slight but significant increase in creatinine clearance was noticed during CNETPV. These results indicate that CNETPV with continuous negative extrathoracic pressure of -10 cm H2O does not induce the major change in ANP secretion and renal function in normal subjects.

Adult↗
PubMed1990

Tumors at the trigone of the lateral ventricle--clinical analysis of eight cases.

Tumors at the trigone of the lateral ventricles are relatively rare. The authors have operated on eight cases with trigonal tumors during a 10-year period. Four cases were true intraventricular tumors arising from the ventricular walls, consisting of two meningiomas, one cavernous angioma, and one choroid plexus papilloma. On the other hand, the remaining four cases were paraventricular tumors originating in the adjacent brain and consisted of three astrocytomas and one glioblastoma multiforme. Although these trigonal tumors were readily detected with computed tomographic (CT) scanning, differential diagnosis was difficult because of their similar appearances on CT scans. The initial symptoms were headache in seven, and the neurological examination revealed personality changes, choked disc, visual field defects, hemiparesis, etc., in four, and no deficits in the remaining four cases. All cases were operated on via superior or middle temporal gyrus incision, and the surgical results were good except for one case who died of postoperative brain edema. In the four cases with tumors located in the dominant hemisphere, two were left with sensory aphasia, dyslexia, dyscalculia, and hemianopsia which improved within 6 months. In these two cases, postoperative CT scans revealed cerebrospinal fluid retention with severe edema along the surgical route which disappeared spontaneously within 3 months. We consider that the temporal gyrus incision was the safest approach, even though the tumor was located in the dominant side.

Adolescent↗
PubMed1990

Topostin, a novel inhibitor of mammalian DNA topoisomerase I from Flexibacter topostinus sp. nov. II. Purification and some properties of topostin.

We describe the isolation of inhibitors of mammalian DNA topoisomerase I, named topostins, from a culture broth of Flexibacter topostinus sp. nov. and some properties of the inhibitors. Topostins A1, A2 and B were isolated by differential solubility in solvents, adsorption chromatography on silica gel and gel filtration on a Sephadex LH-20 column. Topostins A1, A2 and B had specific activities of 4,700, 16,000 and 22,000 U/mg, respectively. The most active metabolite topostin B comprised two components with MW of 567 and 553 in an equimolar ratio.

Chromatography, Affinity↗
PubMed1990

[Inhibitors of DNA topoisomerases].

DNA topoisomerases participate in various aspects of DNA metabolism by their unique catalytic activity of changing DNA topology. Inhibitors of bacterial topoisomerases are antibacterial agents and those inhibiting mammalian counterparts are antitumor agents. What kinds of antitopoisomerase chemicals we have, how they act on topoisomerases, and what is known about the resistance against those agents are briefly reviewed. Furthermore, future problems to be solved in cancer chemotherapy were mentioned.

Animals↗
PubMed1990

[Delayed effects of radiation of patients with germ-cell tumor, with special to cerebral blood flow].

Delayed effects of radiation therapy (RT) on twenty patients with germ-cell tumors, including 17 cases of germinoma, were evaluated with special reference to cerebral blood flow (CBF). All patients except for one of germinoma had craniotomy to verify the tumor histology, then RT followed with a total dose of 39.6 to 60 Gy for each patient. A follow-up study with CT scans and MRI proved not any recurrence of the tumors during the past 14-year period between June, 1975 and April, 1989. On the other hand, CBF was measured by 133Xe inhalation 1 to 14 years after RT. 40% of all patients were below critical values of CBF with higher frequency in the younger. Statistically, the post-irradiated changes of CBF were not related to a total administered dose, grading of brain atrophy, or physical mental developments, but closely related to irradiated volume dose (product of absorbed dose and field, rad.cm3) only for the age ranging from 8 to 15 years at RT. These results suggested that late effects of RT on CBF were more strongly depend upon absorbed dose and field of irradiation to brain in children than in adolescents.

Adolescent↗
PubMed1990

[Cerebellar infarction: analysis of 33 cases].

During the past 9 years and 2 months we have encountered 33 cases with cerebellar infarction. These patients were classified into 3 types according to their clinical course. Type 1 (18 cases); The course was benign, and symptoms and signs improved without surgical treatment. Type 2 (11 cases); The course was progressive with deterioration of consciousness between 24-72 hours after the onset. Type 3 (4 cases); The course was rapid resulting in lapse into coma within a few hours. Also, its prognosis was fatal due to coexisting brain-stem infarction regardless of any treatment. Surgical intervention was required for Type 2 in which the lesion included the region of the vermis or occupied more than one-third of the cerebellar hemisphere, and had subsequently compressed the brain-stem and caused obstructive hydrocephalus. In 9 cases out of Type 2, ventricular drainage alone was performed and prompt improvement of consciousness level was detected except in one case. We consider that ventricular drainage is not so invasive a method, and it is beneficial. However, in 2 cases of Type 1 and 4 cases of Type 2, hemorrhagic infarction occurred. Thus, one should be aware of the possibility of hemorrhagic infarction, even though it may be asymptomatic infarction. If prompt improvement of consciousness is not detected after ventricular drainage, suboccipital craniectomy should be recommended.

Adult↗
PubMed1990

[Effects of negative extra-thoracic pressure ventilation on respiratory system and hemodynamics in normal dogs].

The effects of negative extra-thoracic pressure ventilation (NETPV) on respiratory system and hemodynamics were examined in ten normal dogs. Changes of the parameters obtained during intermittent NETPV (INETPV), and NETPV with negative end-expiratory pressure (CNETPV) were compared with those during IPPV and CPPV. Animals' chests and upper abdomens were confined in an acryl box. In INETPV and CNETPV, the dogs were ventilated with the negative extra-thoracic pressure ventilator (Kimura, OKT-100). Positive and negative pressure ventilation was carefully matched for tidal volume and the increase in FRC obtained with PEEP and the end-expiratory negative extra-thoracic pressure (EENETP). EENETP of -11.6 cmH2O produced the same FRC change as PEEP of 10.6 cmH2O did. Gas exchanges did not differ in any modes. INETPV did not change any hemodynamic parameters without PAP. In CNETPV, heart rate increased, and CVP, cardiac index (CI) and stroke volume (SV) decreased significantly (P less than 0.05), but tmCVP and tmPCWP did not change. The decreases of CI and SV (100----89.1, 88.8%) in CNETPV were significantly smaller when compared with CPPV (100----78.8, 74.5%). In CPPV, meanBP, CVP, tmCVP, tmPCWP, CI, SV changed significantly. The mechanisms of the decrease of CI and SV by CNETPV seemed to be different from those by CPPV.

Animals↗
PubMed1990

[Effects of negative extra-thoracic pressure ventilation on extravascular lung water volume and central blood volume in normal dogs].

In negative extra-thoracic pressure ventilation (NETPV), lung water volume and central blood volume (CBV) could increase because of increased venous return and intensified negative interstitial pressure. The effects of NETPV on the extravascular lung water and CBV were examined in ten normal dogs by the double-indicator method using Na and cold water. The lung water volume measured by the method (EVTV) was compared with the lung water volume measured by the gravimetric method (EVLW) in 17 dogs. EVTV did not show any significant change in any ventilation modes compared with IPPV. CBV decreased from 21.9 ml.kg-1 to 19.2 ml.kg-1 in CPPV compared with IPPV (P less than 0.05). EVTV correlated well (r = 0.91, P less than 0.001) with EVLW. In normal dogs, NETPV did not change the lung water volume and CBV. NETPV dogs do not seem to have any disadvantage in respect of lung water volume compared with conventional positive pressure ventilations.

Animals↗
PubMed1990

[Cerebellar AVM--clinical analysis of 14 cases].

The authors report on their experience with 14 cases of cerebellar arteriovenous malformation (AVM), with emphasis on their clinical symptoms and treatment problems. The incidence of cerebellar AVM was 7.5% in all cases of intracranial AVM. Twelve of them presented with hemorrhages, one with a headache and one with a focal neurological deficit related to the "steal" phenomenon. Three out of 4 poor risk patients with intracerebellar hematoma recovered well after their operations. Thus, we can say that surgical treatment should be performed even if the patient's state seems hopeless. The nidus was located at the vermis in 7, at the cerebellar hemisphere in 5, and at the tonsil in 2 cases. The surgical approach to the superior surface of cerebellum or the tonsil near the brainstem became a problem. In our series, all surgically treated cases were approached through the suboccipital route with the patient in the prone position and the surgical results were favorable. On the other hand, one case which underwent conservative treatment died due to rebleeding. Thus, as the follow-up mortality with conservative treatment is higher and the results of surgery are better, surgical treatment should be attempted. Preoperative MR imaging is one of the useful methods used to determine whether an excision is possible without significant deficit, especially in cases in which the AVM is located near the brain stem. In our series, two patients had concomitant aneurysms related to feeding arteries. Another interesting case of a neonate who had a small tonsillar AVM is reported.

Adult↗
PubMed1990

[Long-term results of cerebral arteriovenous malformations--surgical and conservative treatment].

During the past 20 years, we have treated 187 cases with cerebral arteriovenous malformations (AVMs). These 134 patients were treated surgically and the remaining 53 patients were managed non-surgically. The purpose of this study is to clarify the surgical indications of AVMs, based on a comparison of the long-term follow-up results between the surgical and nonsurgical groups. Consequently, good results were obtained in the surgical group: the operative mortality was 7.5% and the morbidity was 12.7%. The long-term follow-up results were as follows: Of the 124 followed cases in the surgical group, there were 16 cases with improvement of neurological deficits (13%) and 3 cases with neurological aggravation (2%). Of the 47 followed cases in the nonsurgical group, there were 5 cases with improvement of neurological deficits (11%) and 6 cases with neurological aggravation (13%). As for the incidence of AVM hemorrhage, there were 8 cases with hemorrhage in the nonsurgical group including 4 cases (3 rebleeding cases) which were fatal (11%), in contrast to one case (subtotal resection) in the surgical group. On follow-up angiography, the size of AVMs were unchanged in the majority of cases in the nonsurgical group, with the exception of 2 cases in which there were slight regressions. In the surgical group, on the other hand, enlargement in 2 cases and spontaneous regression in 3 of residual AVM occurred following incomplete resection. Particularly in 2 cases involving unresectable AVMs, a newly formed aneurysm was discovered in the follow-up angiography, emphasizing the fact that serious follow-up angiography is required in cases of untreated AVMs.

Adolescent↗
PubMed1989

Persistence and expression of circular DNAs encoding Drosophila amylase, bacterial chloramphenicol acetyltransferase, and others in Xenopus laevis embryos.

We injected circular forms of several different DNAs into fertilized eggs of Xenopus laevis, and studied the persistence and expression of the injected DNAs during early embryonic development. When we injected plasmids which contained Drosophila amylase genes, the copy number of the injected DNA increased only slightly during cleavage, started to decrease at the blastula stage, then became very small at the tadpole stage. In such embryos, Drosophila amylase activity was detected at and after the gastrula stage. When we injected other kinds of circular DNAs (pX1r101A, cDm2055, pII25.1, pBR322, and pSP-64-L14), their copy number did not increase throughout the early stages. When circular plasmids that contained bacterial chloramphenicol acetyltransferase (CAT) genes were injected, their copy number usually did not increase, but sometimes, for unknown reasons, it increased extensively throughout the blastula to gastrula stages. In both cases, CAT enzyme activity started to be expressed during the blastula to gastrula stages and disappeared at the 2 day-old tadpole stage. The level of CAT enzyme activity was roughly proportional to the amount of CAT mRNA formed, and also to the copy number of injected genes. From these results, we concluded that in Xenopus embryos, exogenously-injected circular DNAs are preserved for the most part as circular DNAs, and that the increase in their copy number within the embryos is not prerequisite for the expression of their genetic information.

Amylases↗
PubMed1989

[Intraoperative radiation therapy for malignant glioma].

Intraoperative radiation therapy (IOR) is an ideal means of exterminating residual tumor after surgical resection. In this study, the clinical results of IOR using a Scanditronix Microtron MM-22 were evaluated in 14 patients with malignant glioma, five of whom had recurrent tumors. Between July, 1985 and October, 1986, 11 patients with glioblastoma multiforme (GB) were irradiated 18 times (mean, 1.6 times/case), and three with astrocytoma (Kernohan grade III) underwent IOR once each. The target-absorbed dose at 1 to 2 cm deeper than the tumor resection surface was 15 to 50 Gy. During irradiation, a cotton bolus was placed in the dead space after over 91% of the tumor had been resected. As a rule, external irradiation therapy was also given postoperatively at a dose of 30 to 52 Gy. One patient died of pneumonia and disseminated intravascular coagulation syndrome 1 month postoperatively. The 1- and 2-year survival rates of the remaining 13 patients were 84.6% and 61.5%, respectively; among the 10 with GB, they were 80% and 50%. Generally, the smaller the tumor size, the better the results. There were no adverse effects, despite the dose 15 to 50 Gy applied temporally to the tumor bed. IOR was especially effective against small, localized tumors, but was not always beneficial in cases of large tumors, particularly those with a contralateral focus. The improved survival rate in this series demonstrates that IOR is significantly effective in the "induction of remission" following surgical excision of malignant gliomas.

Adult↗
PubMed1989

[Artifacts in magnetic resonance imaging of the head].

The results of 505 magnetic resonance (MR) imaging examinations of the head disclosed several different types of artifact. Various artifacts observed with two-dimensional Fourier transformation are described and illustrated. All images were obtained with a 0.5 Tesla superconducting MR imager. About 70% of all images contained artifacts. Phase encoding artifacts due to motion or flow were most frequently observed. Center, "zipper," truncation, radiofrequency, and ferromagnetic artifacts and contrast error on inversion recovery (IR) images were noted less frequently. Phase encoding artifacts and contrast errors on IR images totally degraded the images, and "zipper" artifacts were regional. Center artifacts resembled small infarctions, and ferromagnetic artifacts sometimes mimicked hematomas. It is important to recognize these artifacts and to devise methods to avoid their influence on the region of interest.

Brain↗
PubMed1989

[Morphological changes in basement membrane associated with endothelial proliferation in astrocytic tumors--an immunohistochemical study of laminin].

Morphological changes of the basement membrane associated with endothelial proliferation in astrocytic tumors are studied in this report. Laminin is known to be a specific glycoprotein of basement membranes. We applied this characteristic of laminin to enable us to observe various characteristics of the basement membrane. The presence of laminin in 13 glioblastomas, 15 anaplastic astrocytomas, 7 astrocytomas, and 6 pilocytic astrocytomas was examined by peroxidase-antiperoxidase (PAP) staining of formalin-fixed and paraffin-embedded surgical specimens. White matter from five normal cerebral hemispheres obtained during autopsy and subsequently embedded using the same method, were used as a control. Laminin was observed at the glioma-mesenchymal junction in astrocytic tumors, and the deposits of laminin made the tumor vasculature come into intense relief. The destructive changes of the basement membrane, including disruption, thickening, disconnection, dissociation, winding, and conjunction, became greater with progressive endothelial proliferation in astrocytic tumors. Those changes were seen to be most remarkable in glioblastoma. In addition, there was a marked variety of morphological change in the basement membrane in different areas of glioblastomas, although the changes were almost constant in other astrocytic tumors. We present a schematic hypothesis of the stages of angiogenesis in glioblastoma based on the above morphological changes of the basement membrane and discuss it in this report.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[DNA topoisomerases and resistance to anticancer agents].

Since the discovery of several potent anticancer agents which are specific inhibitors of DNA topoisomerases, the key enzymes in the DNA metabolism, efforts to elucidate the mechanism of acquired resistance to these agents and to overcome them have been focused on these enzymes, the cellular targets of the anticancer agents. These trends were briefly reviewed.

Antineoplastic Agents↗
PubMed1989

[Combination therapy with etoposide, adriamycin and cisplatin in advanced primary and recurrent gastric cancer].

Fourteen patients with advanced gastric cancer consisting of seven primary cases and seven recurrent cases were treated with the combination of etoposide, adriamycin and cisplatin (EAP). One of the primary cases (14%) and three of the recurrent cases (43%) responded to the therapy, but a high incidence of toxicities including leukopenia, thrombocytopenia, alopecia, nausea and vomiting was observed. It is concluded that EAP therapy can be useful in the treatment of advanced gastric cancer if countermeasures to the toxicities of these drugs are considered.

Adenocarcinoma↗
PubMed1989

[Hemorrhagic infarction following cerebral vasospasm].

Among 528 cases with ruptured aneurysm, 10 cases (1.9%) developed hemorrhagic infarction following vasospasm. There was no obvious relationship between the occurrence and location of aneurysm and the neurological grade on admission. Hemorrhagic infarction occurred from day 9 to 25 (mean day 16) after aneurysmal rupture, and the major neurological symptoms were aggravation of consciousness level, which appeared in 6 cases. On the CT scans of the hemorrhagic infarction following vasospasm, nine cases revealed heterogeneous hemorrhage as assembled of spotty or linear hemorrhages within the ischemic infarction, and 5 cases had massive hemorrhagic infarction in size with mass effect. Although surgical therapy for 2 cases and conservative therapy for 8 cases were performed, the results were unfavorable; ie, 2 cases were good, 5 fair or poor, and 3 died. Especially, 5 cases with massive hemorrhagic infarction obviously resulted in poor prognosis. In our series, induced hypertension therapy for vasospasm was considered as a risk factor. In conclusion, it is necessary to avoid induced hypertension therapy in the remission stage of vasospasm and serial SPECT study might be recommended as a useful prospective method estimating the vasospasm.

Adult↗