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Biomedical subjects

S Usami

Publications and source records attributed to S Usami.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Risk factors for peptic ulcers treated surgically].

To elucidate the risk factors of peptic ulcer which require surgical treatments, we examined the influences of following factors such as sex, age, smoking, and alcohol in 308 peptic ulcer patients. In the group with gastric ulcers, high age group was likely to be operated. On the contrary, young patients with duodenal ulcers were likely to be treated surgically. Sex, smoking and alcohol were not regarded as risk factors. The correlations between the degree of neurosis and the amounts of smoking and alcohol were analyzed in the cases with duodenal ulcers. In the cases treated surgically, the degree of neurosis showed no or little correlations. In the cases treated conservatively, however, the degree of neurosis showed positive correlation with the amounts of smoking and alcohol.

Adolescent↗
PubMed1988

Factor inducing Agrobacterium tumefaciens vir gene expression is present in monocotyledonous plants.

Agrobacterium tumefaciens harboring the tumor-inducing Ti plasmid incites crown gall tumor on dicotyledonous species. Upon infection of these plants, Ti plasmid DNA sequence is stably transferred (T-DNA) by unknown mechanisms to plant cells to be integrated into nuclear DNA. The T-DNA processing and transfer require the expression of vir (virulence) genes on the Ti plasmid, which are known to be induced by certain phenolic compounds released from cells at the wounded inoculation site. The results of the present study demonstrate that wheat and oats contain a substance(s) that induces vir gene expression, yet the inducing substance of wheat differs from the phenolic inducers in that it is hydrophilic and has a molecular weight of several thousand. The novel inducer was not detectable in the exudates of seedlings of these plants but was found in an extract from the transition region between shoot and root of the seedlings and also in extracts from the seeds, bran, and germ. This finding suggests that T-DNA processing and possibly its transfer should take place when Agrobacterium invades suitable tissues of monocotyledonous plants.

Journal Article↗
PubMed1988

Light- and electron-microscopic study of gamma-aminobutyric-acid-like immunoreactivity in the guinea pig organ of Corti.

With light and electron microscopy, gamma-aminobutyric-acid (GABA)-like immunoreactivity was examined in the guinea pig organ of Corti. In whole-mount preparations, although GABA-like immunoreactivity was present within efferent components in all turns of the cochlea, it was more intense apically. At the ultrastructural level, GABA-like immunoreactivity was clearly restricted to the efferent system, appearing in axons of the inner and tunnel spiral bundles, in axons crossing the tunnel of Corti, and in terminals filled with numerous labeled vesicles synapsing on outer hair cells.

Animals↗
PubMed1988

Immunocytochemical study of catecholaminergic innervation in the guinea pig cochlea.

The enzymes for synthesis of catecholamine, tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyl transferase (PNMT), have been immunocytochemically localized in the guinea pig cochlea. Two groups of catecholamine-containing neurons could be distinguished. The first group, which was TH-positive/DBH, PNMT-negative, was found in the inner spiral bundle and the tunnel spiral bundle. The other group was TH, DBH-positive/PNMT-negative, and was found around the blood vessels. The immunocytochemical evidence obtained in this experiment suggests that the catecholamines should play a functional role in the guinea pig cochlea.

Animals↗
PubMed1988

[Cerebral metastasis from malignant thymoma].

Thymoma with extrathoracic metastasis is very rare, especially to the central nervous system. As far as we know, this is the 15th reported case of cerebral metastasis from malignant thymoma. The prognosis is very poor and almost all of them die in one to one and half years. We have experienced such a case, who is 56 years old man, presenting Gerstmann's syndrome and right-hemiparesis 8 months later after thoracotomy for removal of thymoma. At the admission time in this hospital, CT findings proved the tumor in the left temporoparietal area, left ventricle deformity and slight midline shift to right side. The average of CT density in the low density area was 20. Peripheral region of the tumor was enhanced by contrast CT. Left carotid angiography showed the ACA shift to the right side and abnormal vascularity of peripheral branches of angular artery (arterial phase) and also tumor strain in late artery (arterial phase) and also tumor strain in late arterial phase. Brain scintigram revealed accumulation in the left parietal region. The rt-hemiparesis was rapidly going to be rt-hemiplegia. Therefore, we have performed needle puncture to prevent rt-hemiplegia at the first time. In the course of needle puncture, 90 ml of dark and red fluid was gained at 3.0 cm depth from the cerebral surface. Immediately, the above two symptoms have improved remarkably. Post operative CT showed the reduction of tumor and improvement of the midline shift. The radical operation have been done 2 days after the needle puncture. The tumor was elastic-soft and hemorrhagic and appeared dark-red.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMed1988

[Localization of enolase in the cancer nest of digestive organs].

Gamma-enolase, otherwise called neuron specific enolase (NSE), is specific for neural and neuro-endocrine systems and is present in the tumors of these systems. Gamma-enolase is also reported to be present, however, in a localized form in the tissues of other nonneural systems in some cases of lung cancer in relatively large number of incidences. We examined immunohistologically specimens of digestive organ cancers. Two principal conclusions were obtained. First, gamma-enolase is not specific for neural and neuro-endocrine systems. Second, gamma-enolase is localized in the epithelium of cancers of some cases following the transformation into cancer.

Biomarkers, Tumor↗
PubMed1987

GABA-like immunoreactivity in the chick vestibular end organs.

gamma-Aminobutyric acid (GABA)-like immunoreactivity in the chick vestibular endorgans was examined using an antiserum against GABA coupled with glutaraldehyde to bovine serum albumin. GABA-like immunoreactivity was confined to the cytoplasm of the hair cells in both cristae and maculae. GABA-like immunoreactive cells were evenly distributed throughout the sensory epithelia, and no difference existed between type I and type II hair cells. The results provide evidence that GABA-like immunoreactivity is localized to sensory cells and raises the possibility that GABA may serve as an afferent neurotransmitter in the chick vestibular end organs.

Acetylcholinesterase↗
PubMed1987

GABA-like immunoreactivity in the squirrel monkey vestibular endorgans.

The localization of gamma-aminobutyric acid (GABA)-like immunoreactivity in the squirrel monkey vestibular endorgans was investigated using an antiserum against GABA coupled with glutaraldehyde to bovine serum albumin. GABA-like immunoreactivity was found in nerve fibers and bouton-type terminals, both in the cristae ampullares and the maculae. The location of positive staining corresponded better with known efferent than afferent components of the vestibular periphery.

Animals↗
PubMed1987

Absence in monocotyledonous plants of the diffusible plant factors inducing T-DNA circularization and vir gene expression in Agrobacterium.

T-DNA circularization is one of the molecular events specifically induced in agrobacterial cells upon their infection of dicotyledonous plant cells. We developed a seedling co-cultivation procedure to determine whether or not monocotyledonous plants have the ability to induce T-DNA circularization and vir gene expression. Co-cultivation of Agrobacterium tumefaciens with seedlings of dicotyledonous plants showed that the circularization event takes place efficiently. The exudates and extracts of the seedlings also effectively induced T-DNA circularization and vir gene expression, indicating that dicotyledonous seedlings contain diffusible factors capable of inducing these molecular events. In contrast, neither T-DNA circularization nor vir gene expression was detectable when Agrobacterium was incubated with seedlings of monocotyledonous plants. Supplementing with acetosyringone, a known inducer of vir gene expression and T-DNA circularization, resulted in the induction of circularization during co-cultivation with moncotyledonous seedlings. These results indicate that the seedlings of monocotyledonous plants have no detectable amounts of diffusible inducers, unlike dicotyledonous seedlings. Therefore, it is unlikely that the vir genes are expressed in Agrobacterium inoculated in monocotyledonous plants. This may be one of the blocks in tumorigenesis of monocotyledonous plant by Agrobacterium.

DNA, Bacterial↗
PubMed1987

Cytochemical studies of Ca++-ATPase activity in the vestibular epithelia of the guinea pig.

We used ultracytochemistry to examine Ca++-ATPase activity in the vestibular epithelia of the guinea pig. Many reaction products were found along the basolateral plasma membrane of the vestibular dark cell. There were also marked reaction deposits on the apical and lateral cell membranes of the transitional cells, and the utricular and saccular wall cells. Both sensory and supporting cells showed Ca++-ATPase activity along their ciliary membrane and apical-lateral cell surfaces. Our findings indicate that the Ca++-ATPase activity found on the plasma membrane is closely related to Ca++-transport across the plasma membrane. When either Ca++ or ATP was omitted from the incubation medium, enzyme activity (as seen by the staining reaction present) was completely abolished. Our present results suggest that Ca++-ATPase located in the vestibular epithelia plays a significant role in the regulation of the Ca++-concentration in the vestibular endolymph.

Animals↗
PubMed1987

GABA-like immunoreactivity in the chick basilar papilla and the lagenar macula.

Gamma-aminobutyric acid (GABA)-like immunoreactivity in the chick basilar papilla and lagenar macula was studied by using anti-serum against GABA coupled with glutaraldehyde to bovine serum albumin. GABA-like immunoreactivity was localized selectively in the cytoplasm of both tall and short hair cells in the basilar papilla, and in the hair cell cytoplasm of the lagenar macula. This immunocytochemical finding suggests that GABA may be an afferent neurotransmitter from the hair cell to the primary afferent neuron in the auditory organs of avians and is consistent with previous findings which suggest that GABA may act as an afferent neurotransmitter in the avian vestibular organs as well. However, the distribution pattern of GABA-like immunoreactivity in the afferent system is quite different from the distribution pattern previously described in the mammalian inner ear where GABA-like immunoreactivity is found exclusively within the efferent system.

Animals↗
PubMed1987

Rheology of leukocytes.

The rheological properties of human leukocytes (WBCs) have been studied by micropipette aspiration and filtration tests. A small aspiration pressure applied via a micropipette (diameter approximately equal to 3 micron) causes the WBC to undergo a rapid elastic deformation followed by a slow creep. The data can be analyzed with a viscoelastic model: an elastic element K1 in parallel with a Maxwell element (elastic element K2 in series with viscous element mu). Neutrophils and B lymphocytes are similar in K1, K2, and mu, but these values are higher for T lymphocytes. Treatment of neutrophils with colchicine decreases K2 and mu without changing K1, whereas cytochalasin B decreases all three coefficients; these results indicate the importance of cytoskeletal microtubules and microfilaments in WBC rheology. In the presence of Ca2+, WBCs form protopods which have increased viscoelastic coefficients. Inhibition of protopod formation with pentoxifylline is associated with an increase in WBC deformability. The ruffled surface of the apparently round WBC provides an area about twice that needed to enclose a smooth sphere of the same volume; this geometric feature plays an important role in whole WBC deformability tested through 4-5 micron filter pores or micropipettes. Because of its larger volume and higher cellular viscosity, each WBC is equivalent to approximately 700 erythrocytes in its tendency to block 5-micron channels. The rheology of WBCs has significant implications in their functional behavior, including flow through the microcirculation and interaction with endothelial cells.

Capillaries↗
PubMed1987

Effect of high perilymphatic potassium concentration on the guinea pig vestibular sensory epithelium.

The 'rupture theory' has been proposed to explain the vertiginous attack of Meniere's disease, and the high perilymphatic potassium concentration was thought to be the most important factor in this theory. In this investigation, potassium ion was introduced through the round window into the perilymphatic space in guinea pigs by means of iontophoresis, to investigate the effect of high perilymphatic potassium concentrations on the vestibular sensory epithelium, histochemically. Following the iontophoretic procedure, spontaneous nystagmus was observed, directed toward the iontophoretic side (irritative nystagmus) for the first 10 min, and then toward the unaffected side (paralytic nystagmus) for 24 h. Both these nystagmus types were quite reversible and left no morphological change in sensory cells. However, histochemical analysis revealed an increased ATPase activity during the irritative nystagmus and decreased ATPase activity during the paralytic nystagmus in the synaptic area between the hair cells and the nerve endings of the vestibular sensory epithelium on the iontophoretic side. Judging by these results, high perilymphatic potassium concentration is assumed to affect the synaptic area of the sensory epithelium, leading to reversible nystagmus.

Animals↗
PubMed1987

Rheology of sickle cells and its role in microcirculatory dynamics.

The alterations in the viscoelastic properties of the hemoglobin S solution following deoxygenation can be correlated, on the one hand, with the gelation of the HbS molecules and, on the other hand, with changes in the rheological behavior of the deoxygenated SS erythrocytes. The abnormal rheology of SS erythrocytes forms the basis of their altered flow behavior through filter pores in vitro and microcirculation in vivo. The results support the notion that the rheological behavior of sickle cells is an important link between the molecular events in hemoglobin S following deoxygenation and the behavior of the cell in the microcirculation. Although recent advances have shed considerable lights on the rheology of sickle cells in a variety of conditions, further studies are needed in order to elucidate the pathophysiological role of cell rheology in this disease, especially in terms of the influence of individual SS cells in the heterogeneous populations and the correlation between in vitro and in vivo behavior of SS cells.

Anemia, Sickle Cell↗
PubMed1986

Experimental studies on mechanism of the Menière's attack: investigation into vestibulo-cochlear response of the guinea pig induced by potassium ion.

After introducing potassium ion through the round window into the perilymphatic space of 40 guinea pigs by means of iontophoresis, physiological and histochemical investigations were performed to determine the role of the high perilymphatic potassium concentration in the vertiginous attack of Ménière's disease. About 15 min after the iontophoretic procedure, electronystagmography revealed irritative nystagmus for the first 5 min and then paralytic nystagmus for the following 6 to 24 hr. Histochemical analysis of the vestibular sensory epithelia revealed the increased activity of succinic dehydrogenase and Na-K-ATPase during irritative nystagmus and the decreased activity during paralytic nystagmus. The Na-K-ATPase activity was dominant in the synaptic area between the hair cells and the nerve-endings of the vestibular sensory epithelia. There was some delay between the reversal of nystagmus-direction and the change of enzyme activity. This delay was thought to be produced by the central regulatory mechanism for the disturbed tonus-balance in the vestibular nucleus. On the other hand, electrocochleography revealed the decrease of the action potential without any initial irritative cochlear sign, and the enzyme activity of the cochlear sensory cells was decreased from the beginning.

Animals↗
PubMed1986

Validity of Ewald's law in the horizontal semicircular canals and the vestibular nuclei: electron microscopic observation and quantitative [14C]-2-deoxy-D-glucose study.

Two series of experiments were performed by using a total of 36 guinea pigs. The 1st series was to compare the influence of rotatostimulation on the bilateral cristae ampullare. After repeating the rotatostimulation with the cupulometric mode (the terminal turning velocity: 450 degrees/sec) for 48 hr, ultrastructural changes of sensory cells were found in 9 of 17 animals with transmission electron microscopy. They showed stronger influences on the ampullopetal flow side with the exception of one animal. In the 2nd series, the difference in excitability between the bilateral vestibular nuclei was investigated on 6 guinea pigs which were exposed to the clockwise constant angular acceleration of 1 degree/sec2 for 8 min. The autoradiographic study with [14C]-2-deoxy-D-glucose (the 2-DG) revealed that the rotation-induced glucose uptake was increased significantly in the superior and the medial vestibular nuclei of the ampulloptal flow side. The results of the two series of experiments suggest the predominance of the ampullopetal effect not only in the horizontal semicircular canals but also in the vestibular nuclei.

Animals↗
PubMed1984

Determination of the partition coefficient of 133xenon between oral tissues and blood in the dog.

Ostwald solubility coefficients for 133Xe in plasma (Sp), red blood cells (Sc), and selected oral tissue homogenates (St) obtained from the dog were determined at 4, 20, 27 and 37 degrees C by counting the 133Xe activity of the air phase and the sample (liquid, red cells or tissue) in the same tube following equilibration. The partition coefficient for xenon (lambda, in ml/g) between red cells and plasma (lambda cp) and that between tissues and plasma (lambda tp) were calculated from the measured Sp, Sc and St. The tissue-blood partition coefficients (lambda tb) of oral tissues for 133Xe were then calculated using lambda cp, lambda tp and the haematocrit value. The calculated values of lambda tb at 37 degrees C and 50 per cent haematocrit were 0.650 for the pulp, 0.674 for the tongue, 0.828 for the submandibular gland and 0.881 for the gingiva of the dog. lambda cp increased and lambda tp decreased as the temperature was reduced from 37 to 4 degrees C.

Animals↗