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Biomedical subjects

M Sawada

Publications and source records attributed to M Sawada.

At least 541 records · Page 30Linked to original sources
PubMed1980

[Argyrophil cell of the endometrial adenocarcinoma -light and electron microscopic observations (author's transl)].

Fifty one endometrial adenocarcinomas were used in this study. For light microscopic observations paraffin section from 43 cases were processed with H and E, PAS, and Grimelius argyophil reaction. Besides, 21 of these endometrial adenocarcinomas (25.6%) showed positive Grimelius' argyrophil reaction. With regard to the degree of histological differentiation, these 11 cases were classified as G1 or G2 and all G3 cases (2 cases) revealed negative for Grimelius argyophil reaction. Under electron microscope, in 3 cases out of 21, many small granules reminiscent of neurosecretory type granules mostly round in shape with high electron dense core so often surrounded by a limiting membrane were detected in some of the endometrial carcinoma cells having argyophil granules under light microscope. Since the distribution of these granules was assumed to be random however, the clusters of granules so often located in the groundplasm of subapical portion and subnuclear area near the epithelial basement membrane of the glandular cells. In high magnification, they consisted of an aggregation of fine granular substances with high electron density. Based on the morphological characteristics we made a comparative study between argyophil cell carcinoma of the endometrium and apudomas of the uterine cervix.

Adenocarcinoma↗
PubMed1980

Experimental studies on genital herpetic infection in mice.

Female ICR mice were infected with HSV-1 and HSV-2 by inserting a cotton pellet soaked in viral solution (10(7-8) PFU/m1) into the vagina. The appearance of giant cells and formation of intranuclear inclusions were detected in the epithelial layer of the uterus 24 h after intravaginal inoculation. These histopathological changes were pronounced 3 to 4 days after virus inoculation and then gradually disappeared in the next few days. Results of fluorescent antibody studies on the appearance of viral antigens in infected uterine tissues and results of viral infectivity titrations of emulsified samples of infected uteri coincided well with the histopathological observations on the general course of virus infection. The degree of histopathological involvement caused by HSV-1 was somewhat less than that caused by HSV-2, and the laboratory strains of HSV-1 so far examined (HF and Miyama) were found to be especially weakly pathogenic.

Animals↗
PubMed1980

[Chemotherapy of yolk sac tumor heterotransplanted to nude mice (author's transl)].

Chemotherapy of yolk sac tumor heterotransplanted to nude mice was studied. 1. Yolk sac tumor of the ovary taken from a 38-year -old woman was transplanted to BALB/c female nude mice. The transplantable tumor cells produce a solid tumor, designated as YST-1 tumor. The YST-1 tumor cells preserve the histological appearance of a human yolk sac tumor and produce x-fetoprotein. The tumors on passage 8 were used for experimental chemotherapy. 2. Anticancer drugs clinically known to be effective for ovarian cancer, such as Adriamycin, Carbazilquinone, 5-Fluorouracil, Cyclophosphamide, Mitomycin C, Chromomycin A3, Vinblastine and Bleomycin were administered intraperitoneally to tumor-bearing nude mice. Tumor size was measured two or three times a week during the course of experiments. Therapeutic effects were evaluated by tumor size and relative tumor size before and after experiments. Among these drugs, Vinblastine and Bleomycin combination showed the significant effect arresting the growth of YST-1 tumor.

Adolescent↗
PubMed1979

Electrocochleography of ears with mumps deafness.

Electrocochleography was performed on 16 affected ears of 15 deaf patients whose deafness had resulted from the mumps. Although pure-tone audiometry showed no response in each case, the cases of mumps deafness can be classified into the following three types of cochlear impairment according to the cochlear microphonic (CM) response: (1) no action potential (AP) response but a well-developed CM response, with impairment at the neural level and probable functioning of Corti's organ; (2) absence of both the AP CM responses, with severe impairment of both the neural regions and Corti's organ; (3) no AP response but a decreased CM response, with severe impairment of the neural regions and partial impairment of Corti's organ.

Action Potentials↗
PubMed1978

Arytenoid adduction for unilateral vocal cord paralysis.

The arytenoid adduction technique was devised and performed under local anesthesia on five patients with unilateral vocal cord paralysis. It is especially indicated for the case of a wide, glottal chink and a difference in the level of the two cords. The muscle process is pulled by two 3-0 nylon sutures in simulation of the functions of the lateral cricoarytenoid muscle and the lateral thyroarytenoid muscle. Improvement of voice after surgery was dramatic in all of the patients who were operated on. The surgical procedure is rather simple, easy, and allows adjustment of the degree of arytenoid adduction during surgery to produce the best voice obtainable.

Humans↗
PubMed1978

Colchicine-like effect of diethylstilbestrol (DES) on mammalian cells in vitro.

Diethylstilbestrol (DES), a synthetic estrogen, showed colchicine-like effects in vitro on cells of the cell lines such as Chinese hamster fibroblast of thymus origin (CHT), rat liver (DL), rat erythroblastic leukemia (EDEN-1/TC) and HeLa-S3. Metaphase arrest was induced 3 h after treatment with 15 microgram/ml of DES and polyploid or polynucleated cells were prominently observed more than 24 h after treatment. The arrest, however, was reversible when the agent was removed from the medium. Tetraploid karotypes induced by DES in CHT cells consisted of all double sets of diploid chromosome constitution except one chromosome marker. By clonal selection, several hypotetraploid sublines were successfully isolated from a CHT cell population after the treatment with 15 microgram/ml of DES for 48 h. Some comparative studies of cytological effects of DES with those induced by colcemid indicated that the DES effect was also a mitotic inhibition similar to colchicine.

Aneuploidy↗
PubMed1977

Common bile duct obstruction by hepatoma.

Two cases of hepatoma are presented in which the clinical manifestations of biliary obstruction resulted from growth of hepatoma into the extrahepatic bile duct. Recognition of such a manifestation of the hepatoma may allow for surgical extirpation of the tumor combined with radiation therapy, which may result in long survival.

Adult↗
PubMed1976

Ionic mechanism of 5-hydroxytryptamine induced hyperpolarization and inhibitory junctional potential in body wall muscle cells of Hirudo medicinalis.

Five-hydroxytryptamine (5-HT) causes a hyperpolarization and increased conductance of the leech body wall muscle cell membrane. If 5-HT is applied in the absence of the Cl minus ion, the response appears as a depolarization, whereas if 5-HT is applied in the absence of the K+ ion, the response is a hyperpolarization. In both cases, the conductance of the muscle cell membrane is increased. Stimulation of the peripheral nerve to the body wall muscle produces a complex junctional potential in muscle cells. Exposing the muscle to d-tubocurarine (d-TC) eliminates the excitatory component (EJP) of the complex potential. The inhibitory potential (IJP) that remains has an equilibrium potential at approximately 65 mV. Furthermore, this IJP appears as a depolarization when the nerve is stimulated in the presence of d-TC and low CL minus, whereas this is not the case if the nerve is stimulated in the presence of d-TC and low K+. The drugs BOL-148 and cyproheptadine block the IJP's in the body wall muscle. These data are interpreted as indicating that 5-HT acts on leech body wall muscle cells by increasing the conductance to the Cl minus ion and that the IJP's caused by nerve stimulation are probably the result of 5-HT release at nerve terminals. As a final point, it has been shown that the inhibition by 5-HT of the spontaneous EJP's that occur on the leech body wall muscle results from an inhibition of central neurons and not from any direct effect on the muscle cell or on peripheral synapses.

Animals↗
PubMed1976

Anatomical basis for an apparent paradox concerning conduction velocities of two identified axons in Aplysia.

Larger axons usually have faster conduction velocities, lower thresholds, and larger extracellular action potentials than smaller axons. However, it has been shown that the largest fiber, R2, in the right pleurovisceral connective of the marine mollusc, Aplysia, has a higher threshold and a slower conduction velocity than does the smaller axon of cell RI, even though the amplitude of R2's spike is larger than R1's spike. One explanation of this apparent parodox is that the two axons have different "intrinsic membrane and axoplasmic constants" (Goldman, L. (1961), J. Cell Comp. Physiol. 57: 185-191). However, the deep infolding of R2's axonal membrane suggested that differences in the shape of the two axons might also account for the paradox. Accordingly, we measured the conduction velocities of the two axons and then examined the same axons in the electron microscope in order to measure their volumes and surface areas. Our morphological observations indicate that the extensive infolding of surface membrane causes R2 to have a smaller volume to surface area ratio than R1. Thus, since conduction velocity is proportional to the square root of the volume to surface area ratio (Hodgkin, A.L. (1954), J. Physiol. 125: 221-224), it is predictable that the smaller axon would have a faster conduction velocity. The results suggest that the paradoxical conduction velocities can be explained largely as resulting from differences in the shapes of the two axons. However, certain discrepancies between the measured and the predicted values suggest that other factors are contributing as well.

Animals↗
PubMed1976

The identification of two inhibitory cells in each segmental ganglion of the leech and studies on the ionic mechanism of the inhibitory junctional potentials produced by these cells.

The present study identifies a pair of inhibitory cells that are located on each anterolateral margin of a leech segmental ganglion. These cells, which we label as cells 119, are electrically interconnected. These cells give rise to inhibitory junctional potentials (ijp's) in contralteral longitudinal body wall muscle cells. The latencies of the ijp's following spikes in cell 119 are variable. The ijp's are caused by transient increases in premeability to the Cl- ion. Previous studies demonstrated that 5-HT causes a hyperpolarization of body wall muscle cells by increasing the permeability of muscle membrane to the Cl- ion. Accordingly, 5-HT was searched for in the 119 cell bodies, but autoradiography, fine structure, and gas chromatography-mass spectrometry gave no indication that 5-HT was present in these cells. However, the variable latencies of the ijp's may indicate that there is a neuron interposed between cell 119 and the muscle cells. If this is the case, then the interposed neuron should be analyzed for 5-HT. Further experiments to locate the terminals of cells 119 and the cell bodies of the presumed interposed neurons are thus desirable.

Action Potentials↗
PubMed1976

A central inhibitory action of 5-hydroxytryptamine in the leech.

Previous studies indicated that 5-HT reduced the number of spontaneous excitatory junctional potentials (ejp's) that occurred in leech body wall muscle cells. The present study confirms these findings and shows that the ejp's arise from impulses in motoneuron L. This study further shows that 5-HT acts by hyperpolarizing and reducing the membrane resistance of neuron L, thus inhibiting the motoneuron and reducing the frequency of spontaneous ejp's on body wall muscle cells. These effects of 5-HT are not seen when the ganglion is bathed in a high magnesium solution, a finding that suggests that 5-HT does not act directly on the membrane of motoneuron L. This study demonstrates that 5-HT can have a central inhibitory effect on body wall muscle contractions. Previous studies provide evidence that 5-HT may act as a direct neuromuscular inhibitory transmitter and may also take part in peripheral presynaptic inhibition. Thus, if further studies confirm these suggestions, the well-known inhibitory effect of 5-HT on leech body wall muscle is a more complex process than was previously thought.

Action Potentials↗