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Biomedical subjects

A Handa

Publications and source records attributed to A Handa.

At least 73 records · Page 4Linked to original sources
PubMed1994

Ribbon enchephalo-duro-arterio-myo-synangiosis for moyamoya disease.

In patients with advanced moyamoya disease, reconstructive surgery alone may not prevent the deterioration of blood flow in the territory of the anterior cerebral artery. These types of surgery include superficial temporal artery-to-middle cerebral artery anastomosis and encephalo-duro-arterio-myo-synangiosis (EDAMS). Bilateral encephalo-duro-arterio-synangiosis (EDAS) gradually reduced the transient ischemic attacks in one of our patients who experienced motor weakness in the left extremities. After surgery, however, persistent bilateral attacks still occurred in the patient's legs. In a subsequent maneuver, we inserted the pedicle of the galea on both sides into the interhemispheric fissure, which induced marked vascularization in the territory of the anterior cerebral artery, and the attacks disappeared. Since then, we have combined this "ribbon" technique with EDAMS to treat eight patients with moyamoya disease. Postoperative angiograms showed widespread collateral circulation on the ischemic brain surface in six patients undergoing ribbon EDAS or EDAMS. Postoperative measurements of cerebral blood flow revealed improved circulation in the frontal region in four patients. The clinical results were excellent in six patients, and good in one, and we lost follow-up in one. The ribbon EDAMS procedure is effective on moyamoya disease with symptomatic cerebral ischemia of the anterior circulation.

Adolescent↗
PubMed1994

Selection and combination of techniques for treating spontaneous carotid-cavernous sinus fistulas.

Twenty-eight patients with spontaneous carotid-cavernous sinus fistulas (CCFs) were treated using a variety of techniques. Three of four patients with direct CCFs underwent intravascular embolization with a detachable balloon. Embolization with polyvinyl alcohol particles through an external carotid endoarterial route was used in six patients with indirect CCFs, and with ethylene-vinyl alcohol copolymer solution in two. Patients undergoing these conventional treatments, including embolization of the meningeal branches of the external carotid artery, had less satisfactory outcomes. The transvenous approach using minicoils through the inferior petrosal sinus was successful in eight patients. One patient treated using the transvenous approach using copper wire through the ophthalmic vein had worsening of visual acuity and field. Unsuccessful transvenous embolization in four patients required direct surgical exposure and embolization with spring coils. Spontaneous cures occurred in four patients. Direct CCFs with high flow rates were best treated with the detachable balloon or coil technique through a internal carotid endoarterial route. Indirect CCFs were best treated with the minicoil through the inferior petrosal sinus. If these techniques fail, direct surgical exposure allows placement of coils into the cavernous sinus.

Adult↗
PubMed1992

[A case of encephalitis with MRI abnormalities localized in the bilateral amygdala and hippocampus].

We report a patient with encephalitis who showed anterograde and retrograde amnesia with MRI abnormalities localized in the bilateral amygdala (AM) and hippocampus (HIPP). A 25-year-old man suddenly experienced a generalized tonic-clonic seizure (GTCS). He was admitted because of increasing lethargy with two further GTCSs during the following 6 days. The patient had high fever, and neurological examination revealed somnolence, disorientation, amnesia, and nuchal stiffness. MRI revealed bilateral symmetrical abnormalities localized in the AM and HIPP, which showed low intensity on T1-weighted images and high intensity on T2-weighted images. Cerebrospinal fluid examination showed a mildly elevated cell count. We suspected herpes simplex virus type I encephalitis and began treatment with acyclovir. After the patient regained a clear consciousness, his antero- and retrograde amnesia continued for several months. The MRI abnormality became less distinct with the improvement of amnesia. We consider that the MRI abnormality was indicative of inflammation and edema, and that the lesion in the AM and HIPP had induced the amnesia.

Acyclovir↗
PubMed1992

[Transient second-degree A-V block during an epidural procedure].

A 26 year old pregnant female had a left ovarian tumor and was scheduled to have an operation. No specific complication was noted preoperatively except pregnancy of 16 weeks and one day. Spinal anesthesia for the operation and continuous epidural catheter placement for postoperative pain relief were planned. During the epidural procedure on L2-3 under left lateral recumbent position, patient developed a bradycardia when the tip of Tuohy needle touched the 3rd lumbar bone (lamina arcus vertebrae). This bradycardia occurred three times and the last episode was recorded on the ECG (Fig 2). Blood pressure at this period was 82/44 mmHg, but patient did not complain any discomfort. The recorded ECG showed II degree A-V block (Wenkebach type). We considered this A-V block is probably due to sharp pain from touching of Tuohy needle on the lamina arcus vertebrae. This kind of periosteal pain is sometime associated with vagal stimulation and it could produce II degree A-V block. During a spinal or epidural procedure, ECG should be monitored and we have to pay attention to these kinds of arrhythmia to prevent more profound hemodynamic changes.

Adult↗
PubMed1991

Inhibition of infection with human immunodeficiency virus type 1 by sulfated gangliosides.

Four kinds of gangliosides, namely GM1a, GD1a, GD1b and GT1b and their sulfated derivatives were examined for antiviral activities against human immunodeficiency virus type 1 and abilities to modulate CD4 antigen on the cell surface. The infection of human T cells with the virus was markedly inhibited by treatment with the sulfated gangliosides at a concentration of 10 micrograms/ml, while the non-sulfated gangliosides had only weak antiviral activities. The sulfated gangliosides completely inhibited syncytium formation induced by HIV-1 at 30 micrograms/ml. The CD4 antigen on the surface of T cells became hardly detectable after treatment with them. They did not damage cells, nor prolong the activated partial thromboplastin time at concentrations of up to 100 micrograms/ml, suggesting that they may have little side effect in vivo.

Animals↗
PubMed1990

Alkali light chains are involved in stabilization of myosin head.

1. Fast skeletal myosin subfragment 1 (S1) was separated into two isozymes, S1(A1) and S1(A2), based on the associated alkali light chain, and their thermostabilities were compared. 2. Inactivation rate constants of Ca2(+)-ATPase (at 30 and 35 degrees C) were higher and heat-induced turbidity increase at 340 nm (at 40 degrees C) was faster with S1(A1) than with S1(A2), indicating a higher stability of S1(A2). 3. When S1 isozymes were incubated in the presence of excess alkali light chain, turbidity increase was markedly reduced, depending on the amount of light chain added. 4. Results obtained strongly suggest that alkali light chains are involved in the maintenance of myosin head structure.

Animals↗
PubMed1990

Possible presence of the difference peptide in alkali light chain 1 of fish fast skeletal myosin.

1. Presence of N-terminal peptide ("difference peptide") in alkali light chain 1 (A1) of fish fast skeletal myosin was examined by comparing two kinds of light chain-based myosin subfragment 1 (S1) isozymes from the yellowtail Seriola quinqueradiata. 2. On tryptic digestion, A1 was cleaved to a smaller fragment (mol. wt decrement by 2000) along with the cleavage of S1 heavy chain, while A2 was resistant to trypsin. Two-dimensional gel electrophoresis showed that A1 released a basic peptide by tryptic digestion. 3. Both S1 isozymes showed clear kinetic differences in actin-activated Mg-ATPase activity, suggesting a higher affinity of A1 for actin. Affinity of A2 for heavy chain was also estimated to be about 2-fold higher than that of A1, as judged by the model experiments in which rabbit S1 isozymes were hybridized with heterologous alkali light chains.

Actins↗
PubMed1987

A comprehensive study on the mechanism of inhibition of serine proteases by benzamidines based on quantitative structure-activity relationship studies.

Based on quantitative structure-activity relationship studies, investigation is made on the mechanism of inhibition of serine proteases, i.e., thrombin, plasmin, trypsin, and complement, by benzamidines. It is found that inhibitions of all the four enzymes, thrombin, plasmin, trypsin and complement, involve hydrophobic interaction in general but they do not involve electronic interaction in all the cases. In the cases where the electronic interaction is involved the mode of interaction is not necessarily the same. The electronic interaction depends upon the kind and the source of the enzyme.

Amidines↗
PubMed1987

Quantitative structure-activity relationship study on hexestrol and metahexestrol derivatives interacting with estrogen receptors.

The estrogen receptor binding affinity of various hexesterol derivatives is found to be significantly related with van der Waals volume of substituents and the Hammett constant sigma. This led to suggest that substituents produce steric effects on the drug-receptor interaction and that the electron-donating capability of substituents enhances the activity. In case of metahexestrol derivatives these factors were however not found to affect the binding affinity of compounds. The reason thereof is discussed.

Chemical Phenomena↗
PubMed1987

Quantitative structure-activity relationship study on amsacrine derivatives.

Various biological activities of amsacrine derivatives were analyzed in relation to various physico-chemical parameters. The in vitro activity parameters like DNA-binding and cell inhibition constants were found to have significant correlations but with varying physico-chemical parameters. DNA-binding constants were found to be the function of van der Waals volume and the cell inhibition constant to be the function of the hydrophobic parameter. But the in vivo antitumor activity parameters like optimal dose administered intraperitoneally in mice injected with P388 leukemia cells and the percentage increase in life span of treated animals over that of control animals were not found to be related with any property of the molecules.

Amsacrine↗
PubMed1987

On the evaluation of gas-liquid interfacial effects on hybridoma viability in bubble column bioreactors.

Sparger aeration, with or without mechanical agitation is the simplest method of providing an oxygen supply. Although earlier workers have demonstrated the sensitivity of mammalian cells to air bubbles, recent successful applications of the airlift principle to hybridoma culture indicate that under some conditions, the cells can withstand these effects. Therefore, this work has as its objective the elucidation of the relationship between gas-liquid interfaces and the survival of mammalian cells. Simple, 0.5 litre bubble columns with sintered discs are used batch-wise to study the effects of sparging on hybridomas and other mammalian cells in suspension culture. The effects of bubble diameters, superficial gas velocities and the non-ionic surfactant, Pluriol PE 6800, are investigated in cultures grown in RPM1 1640 with 5% foetal calf serum and 6 ppm silicone antifoam. From these studies it has become apparent that cell viability and survival in the presence of bubbles depend on: Cell type--Some cell lines are shown to be particularly sensitive to the presence of bubbles, although no gross morphological differences are detected by electron microscopy. Bubble sizes--At a superficial gas velocity of 0.42 X 10(-4)m/s (5 cc/min gas flow rate), small bubbles are shown to be more detrimental to the cells than the larger ones. Bubble frequency/superficial gas velocities--Increasing superficial gas velocities (0.42 X 10(-4) to 8.5 X 10(-4) m/s) result in decreasing cell viability. Where the presence of bubbles is detrimental to cell growth, the addition of the non-ionic surfactant, Pluriol PE 6800, has a concentration dependent protective effect. Surface tension, viscosity and bubble diameter data for typical medium will be presented. A novel application of microscopy to which video film systems can be applied for direct visualisation of the cells in the bubble column has been developed. From these studies, it is indicative that both the geometry of the system and the cell type are important in mammalian cell culture scale-up strategy.

Animals↗
PubMed1985

Quantitative correlations of biological activities of dactinomycin analogs and methotrexate derivatives with van der Waals volume.

The biological activities namely the ability to bind with DNA base pairs and the in vitro inhibition of human lymphoblastic leukemia cells of certain C-7- and N2-substituted dactinomycin (actinomycin D, AMD) analogs, and the growth inhibitory activity of a series of side chain substituted methotrexate (MTX) derivatives against L 1210 mouse leukemia cells in culture and their binding affinity for dihydrofolate reductase (DHFR) enzyme extracted from this system and L. casei are found to be significantly correlated with van der Waals volume of the substituents. In case of MTX derivatives, not only the side chain substituted analogs but certain ring substituted analogs, too, are shown to have their different activities dependent upon the Vw of the substituents. In case of side chain substituted analogs, however, it is found that the size of the substituent of alpha-position produces a greater effect on the activity than that of gamma-position. Based on the correlating equations obtained it is assumed that in these cases the drug-receptor interaction might be involving either hydrophobic interaction or the van der Waals type of interaction.

Animals↗
PubMed1984

Correlation of biological activities of mesoionic and benz-fused mesoionic xanthine analogs with van der Waals volume and molecular connectivity.

The adenosine cyclic 3',5'-monophosphate (c-AMP) phosphodiesterase (PDE) inhibitory activity of a series of mesoionic 1,3,4-thiadiazolopyrimidines and of a group of benz-fused mesoionic xanthine analogs are found to be significantly correlated with the van der Waals volume (VW) of the substituents or the first order valence connectivity index (1 chi V) of the molecule. From the correlating equations it is observed that the size of the substituents at certain positions, of pyrimidine ring particularly, in the molecule are determinative to the activity. Further based on these equations it may be suggested that PDE inhibition by this class of drugs involves either hydrophobic interaction or van der Waals type of interaction. In certain cases steric and electronic factors are also indicated to affect the inhibition.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

A quantitative analysis of steric and hydrophobic effects in ribonucleoside diphosphate reductase inhibition by thiosemicarbazones.

Ribonucleoside diphosphate reductase (RDR) inhibitory activity of 2-formylpyridine and 1-formylisoquinoline thiosemicarbazones is quantitatively analysed in relation to a steric parameter (van der Waals volume, VW) and the hydrophobic parameter logP. The activity is found to be significantly correlated with VW and very poorly with logP. On the basis of this, it is inferred that RDR inhibition by thiosemicarbazones is very sensitive to steric effects and is little influenced by the hydrophobic character of the molecules.

Chemical Phenomena↗