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Biomedical subjects

T Iijima

Publications and source records attributed to T Iijima.

At least 307 records · Page 17Linked to original sources
PubMed1990

Three-dimensional cytoarchitecture of the media of arteriovenous anastomoses in the rabbit ear.

Arteriovenous anastomoses in the rabbit ear were examined with scanning electron microscopy to elucidate the structural differentiation of the media of the shunt. Arterial, intermediate, and venous segments in the shunt and two layers of the media in the intermediate segment were differentiated based on cell shape and cell organization. In the arterial segment, smooth muscle cells were spindle-shaped, either elongated or short, with a few branches, and were arranged circularly or diagonally with respect to the vessel's long axis. There were also stellate muscle cells with radiating processes. In the intermediate segment, the smooth muscle cells of the outer layer of the media were also arranged circularly and resembled the elongated cells in the arterial segments, but they were more irregular in shape and had more processes than those of the arterial segment. The epithelioid cells of the inner layer of the media were oval or polygonal and oriented irregularly with respect to the vessel's long axis, clustering to form longitudinal plicae. The smooth muscle cells of the venous segment were flat with many lateral processes and formed a thin, discontinuous layer. The smooth muscle cells in the arterial segment and those of the outer layer of the intermediate segment exhibited a highly rugged surface texture, indicating their strong contractility; the epithelioid cells and the smooth muscle cells in the venous segment exhibited a generally smooth surface, indicating less contractility. The intermediate segments were supplied with a dense nerve plexus. The intermediate segments, therefore, may be actively involved in the regulation of blood flow under neuronal influence.

Animals↗
PubMed1990

Indocyanine green (ICG) test before and after exercise in patients with chronic liver diseases.

The indocyanine green (ICG) test (serum disappearance rate: K and 15 min. retention rate: R15) was performed in 15 patients with chronic hepatitis (CH) and 22 patients with liver cirrhosis (LC) before and after exercise (Master's two step method for three min.). In LC, ICG K was 0.063 +/- 0.026 (mean +/- SD) before exercise and 0.083 +/- 0.028 after exercise. ICG R15 was 31.6 +/- 15.6% and 23.3 +/- 15.3%, respectively. In CH, ICG R15 before exercise was 8.2 +/- 4.0%, as compared with that (5.7 +/- 3.6%) after exercise. Namely, the ICG test significantly (P less than 0.05) improved after exercise in chronic liver diseases. Excretion of ICG into bile after exercise increased both in gallstone patients without abnormal liver function and LC, and it markedly increased in patients with decompensated LC. There was no significant difference in ICG excreted into urine before and after exercise. These results suggest that hepatic blood flow increases through moderate exercise in chronic liver diseases.

Bile↗
PubMed1990

Simultaneous recordings of cytosolic Ca2+ level and membrane potential and current during the response to thyroliberin in clonal rat anterior pituitary cells.

The response to thyroliberin in prolactin-producing rat GH4C1 clonal cells was studied using fura-2 to monitor the cytosolic Ca2+ level ([Ca2+]i) in single cells, combined with recordings of membrane potential and current. The average value of [Ca2+]i was 109 nM (mean +/- SD, n = 112), and evoked action potentials caused transient elevations of about 100 nM. At higher firing frequencies these transients merged to a sustained elevation. In 100% of the cells thyroliberin caused an instant rise in [Ca2+]i, peaking at 795 +/- 300 nM (n = 112). This first phase of the thyroliberin response was associated with hyperpolarization in current clamp and outward current in voltage clamp, caused by the opening of Ca2(+)-activated K+ channels. In 75% of the cells the initial peak in [Ca2+]i was followed by a prolonged plateau phase at 247 +/- 76 nM (n = 84). In current clamp the second-phase elevation of [Ca2+]i was linked to either a modest depolarization in combination with enhanced firing frequency or a more pronounced depolarization in silent cells. This elevation of [Ca2+]i was reversed by hyperpolarizing current injection. No second-phase elevation of [Ca2+]i was observed during voltage clamp at a holding potential of -50 mV. Short exposure to Ca2(+)-free conditions eliminated the second-phase elevation in [Ca2+]i, whereas the first phase remained intact. Our experiments show a direct relationship between electrical activity and [Ca2+]i in the GH4C1 cells. The second-phase elevation of [Ca2+]i caused by thyroliberin is the result of influx through voltage-sensitive Ca2+ channels, without involving agonist-gated channels.

Animals↗
PubMed1990

Rapidly absorbed solid oral formulations of ibuprofen using water-soluble gelatin.

Rapidly absorbed oral dosage forms of ibuprofen using water-soluble gelatin (hydrolysate of common gelatin: mean mol. wt: 6000) have been studied and compared with tablets prepared with common gelatin (mean mol. wt: 100,000) and commercial tablets. Spray-dried and speed-kneaded powders, two types of granules and tablets were prepared with water-soluble gelatin. The in-vitro dissolution rates of water-soluble gelatin preparations were significantly faster than those of commercial tablets, whereas the tablets prepared using common gelatin had slower dissolution rates than commercial tablets. Water-soluble gelatin enhanced the dissolution rate of ibuprofen by improving the wettability of the drug particle surface by water, without any interaction in solution and the solid state. The absorption behaviour of various preparations was evaluated in four beagle dogs. The peak concentration time (tmax) of the water-soluble gelatin preparations was significantly shorter than that of tablets prepared with common gelatin and commercial tablets. The maximum concentration (cmax) and the area under the serum concentration-time curve (AUCo-10 h) were similar in all cases. The serum concentration profiles of water-soluble gelatin solid preparations were almost the same as those of the solutions. On the other hand, the profiles of the common gelatin tablets were similar to those of the commercial tablets. The mean absorption time (MAT) from water-soluble gelatin preparations was about 0.7 h, while the MAT from commercial tablets and common gelatin tablets was about 1.2 h. The differences in the MAT of water-soluble gelatin preparations and commercial tablets or common gelatin tablets were the same as the differences in mean dissolution time (MDT) in gastrointestinal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Endocytosis in odontoclasts and osteoclasts using microperoxidase as a tracer.

Microperoxidase (MP, a peptide tracer) was intravenously injected into rats after six days of tooth movement by the Waldo method. Bone resorption was seen along the distal bone surface of the inter-radicular septum of the upper first molar, and tooth root resorption occurred along the mesial and distal surfaces of the distal root of the same molar. Odontoclasts were smaller in size and numbers than osteoclasts, but had the same organelles [multiple nuclei, ruffled borders (RB), clear zones, vacuoles, mitochondria, and specific granules] as osteoclasts. MP was deposited on the resorbed area through the clear zone and was transported into the vacuoles along the channels of the RB. The uptake of MP by odontoclasts was small, compared with that by osteoclasts. Collagen fibrils were found in the channels of the RB but were not detected in the vacuoles. Instead, filament-like structures were seen in the vacuoles and were located very near the collagen fibrils in the channels. Fibroblasts outside the resorbed lacunae had endocytosed collagen. In contrast, some cells close to odontoclasts (osteoclasts) in the dentin (bone)-resorbed lacunae had not endocytosed any collagen fibrils. These findings suggest (1) that odontoclasts resorb the dentin or cementum just as osteoclasts do in bone resorption, (2) that the resorbed area connects with the extracellular spaces of the odontoclasts or osteoclasts, and (3) that the organic components (e.g., collagen fibrils) of dentin or cementum are endocytosed through the channels of the RB in the same manner as that for MP. However, the endocytotic ability of odontoclasts appears inferior to that of osteoclasts.

Animals↗
PubMed1990

Differential modulation by beta adrenoceptors of inward calcium and delayed rectifier potassium current in single ventricular cells of guinea pig heart.

This study was designed to investigate the modulation of the high-threshold (L-type) inward calcium current (ICa) and the delayed rectifier potassium current (IK) by beta adrenoceptor stimulation in single ventricular cells of guinea pig heart. Single ventricular cells were prepared by the collagenase dispersion procedure, and membrane currents were recorded with a patch electrode by use of the whole-cell voltage clamp method. ICa was obtained by intra- and extracellular perfusion with the Cs(+)-solutions that suppressed potassium currents. IK was evaluated in Co+(+)-Tyrode's solution in which 0.9 mM Co+(+) was substituted for equimolar Ca+(+) to abolish ICa. Isoproterenol, a nonselective beta adrenoceptor agonist, increased not only ICa but also IK at the same threshold concentration (1 nM). In contrast, the threshold concentration of T-1583, a selective beta-1 adrenoceptor agonist, for increasing ICa (1 nM) was distinctly lower than that for increasing IK (100 nM). These results suggest that ICa and IK can be differentially modulated by beta adrenoceptors.

Adrenergic beta-Agonists↗
PubMed1990

Advanced carcinoma of the stomach treated with definitive proton therapy.

We report the case of a 72-yr-old man who suffered from severe chronic emphysema with poor pulmonary function, and who had advanced cancer of the stomach. Proton beam radiotherapy was applied to the lesion, since surgery was contraindicated. The total dose to the stomach lesion was 61 Gy in 7 wk. The tumor on the stomach regressed, with flattening of the round wall of the lesion. The reactive changes of the proton beam radiotherapy, based on the histopathological examination, revealed extensive tumor necrosis and sparing of vital architecture of normal tissue around the irradiated tumor tissue. Only small clusters of vital or devitalized tumor cells with less than approximately 5% of the whole tumor tissue remained after treatment. We suggest that a high dose of radiation delivered by well-defined proton field could result in an improved therapeutic outcome without undue risk of injury to normal tissue.

Adenocarcinoma↗
PubMed1990

Improvement of the frequency responses in an ambulatory ECG system by the natural observation method.

The ambulatory ECG system has been used not only in detecting arrhythmia but also in the diagnosis of myocardial ischemia. Therefore, it is necessary to reproduce ECG waveforms as accurately as possible. However, ambulatory ECG waveforms which are in clinical use are apt to be distorted because the frequency responses do not satisfy the AHA (American Heart Association) recommendation which is well accepted as the standard of the conventional ECG system. An improvement of frequency response is reported here using a compensation circuit, whose theory is based on the natural observation method. Since our system is adjusted with square waveforms and composed of a simple analog circuit, it can be compensated easily in real time. In this paper, our newly developed system and various improved ECG signals are presented and compared with conventional ECG signals. As a result, we could obtain less distorted waveforms than from commercially available devices. This new approach enables us to obtain diagnostic information of the distortion-free ST segment in ECG waveforms.

Arrhythmias, Cardiac↗
PubMed1990

[A case of right duplex kidney with double ureters and left dysplastic kidney with bifid ureter].

During dissecting practice for students, a case of anomalous urinary tracts was found in a 81 year-old Japanese female cadaver which had an extraordinarily large right kidney with double ureters and a dwarf left kidney with a bifid ureter. The histological investigation on the left kidney revealed the renal dysplasia including thyroid gland-like widening of urinary tubules and the hyperplasia of interstitium. No renal corpuscles were observed besides very few primitive ones. Two ureters originating from the left kidney united each other in the proximal portions and the united ureter ran down the normal pathway to the urinary bladder. The left ureter was thin and underdeveloped but the circular and the oblique musculature were distinguished in the distal three quarters of the ureter. The right large kidney was shown to be a duplex kidney. Both the upper and the lower poles were well-developed and histologically normal except the compensatory hypertrophy of the cortex obviously resulting from the dysplasia of the left kidney. The upper and the lower pole ureters draining the duplex kidney never crossed each other and entered the bladder through adjoining two ureterovesical junctions at the normal position. The possible embryological basis for these anomalies was discussed.

Aged↗
PubMed1989

Lung cancer-associated monoclonal antibody 15 that recognizes cell growth-related membrane antigens gp85/45 and its growth-inhibitory effect on human lung cancer cells in vitro.

In order to find lung cancer-specific markers, monoclonal antibody 15 (MAb15) was produced against a variant-type cell of small cell lung carcinoma. Its gp85/45 antigens were demonstrated in 70% of lung cancers, and particularly in the proliferating zone of cancer cell nests, but they are scarcely detected in noncancerous tissues. Immunoelectron microscopy revealed that gp85/45 antigens were expressed alternatively on the cell membrane of living cancer cells according to their biological states. MAb15 added to the culture medium inhibited the proliferation of lung cancer cells, depending on its concentration, but cell death rate did not increase. The growth inhibition by MAb15 was reevaluated by a colonogenic assay. On DNA histogram, MAb15 decreased the number of DNA-synthesizing cells in the S phase with an elevation of the G1 peak, indicating a G1-S boundary block in the cell cycle. gp85/45 detected by this lung cancer-associated monoclonal antibody could be a functional membrane unit, such as a growth factor receptor, which is related to the cell proliferation of lung cancer. The growth inhibition by MAb15 may be caused by the blocking of a growth factor receptor which is specific to lung cancer.

Antibodies, Monoclonal↗
PubMed1989

[Clinical studies using a highly sensitive radioimmunoassay for mid-region and carboxy terminus of parathyroid hormone in normal, hypo- and hypercalcemic states].

Parathyroid hormone radioimmunoassay (RIA), specific for mid-region of the PTH molecule, has been proven to be extremely useful for the differential diagnosis of abnormal calcium metabolism. Recently, we developed a highly sensitive RIA for PTH, consisting of PTH antiserum (CH9), 125I labelled Tyr42 hPTH (43-68) and synthetic hPTH (1-84) as standard. This RIA cross-reacted with mid-region and carboxyl terminals of PTH. The within-assay and between-assay coefficients of variation were less than 4.6% and less than 8.6%, respectively. The limit of detection was 50pg/ml. The levels of serum calcium, serum phosphate, serum creatinine, Tmpo4/GFR and creatinine clearance (Ccr) in normal healthy volunteers aged 20 to 50 years remained almost constant and showed 9.24 +/- 0.34mg/dl (mean +/- SD, n = 242), 3.34 +/- 0.38mg/dl (n = 242), 0.870 +/- 0.121mg/dl (n = 242), 3.20 +/- 0.54mg/dl GF (n = 189) and 103 +/- 17ml/min (n = 137), respectively. All healthy volunteers (n = 326) had measurements of PTH in the blood. From 20 to 50 years, normal PTH mean was 374 +/- 97pg/ml (+/- SD, n = 237) and ranged from 180-568pg/ml, and from 60 to 80 years it was 471 +/- 133pg/ml (n = 34) and ranged from 205-737pg/ml. Since we found that PTH was markedly elevated above normal when Ccr was below 40ml/min, and PTH was very significantly correlated with the reciprocal of Ccr (r = 0.8996, P less than 0.001) using a multivariate analysis, all of the patients whose Ccr was higher than 40ml/min were selected and examined in the following studies. Serum PTH values completely separated patients with surgically proven primary hyperparathyroidism (1 degree HPT) from malignant associated hypercalcemia (MAH), and patients with idiopathic hypoparathyroidism (IHP) from pseudohypoparathyroidism (PHP), both of which were diagnosed by Ellsworth-Howard test. PTH values in all of the patients with 1 degree HPT (n = 23) were above normal, but those with MAH (n = 6) were below the normal or lower normal range. PTH values in patients with PHP (n = 7) showed above normal, while those with IHP (n = 5) were below the normal range. PTH was normalized in post operative status in all patients after parathyroidectomy (n = 6). These results indicate that this PTH RIA is extremely useful for the differential diagnosis in diseases with calcium abnormalities.

Adolescent↗
PubMed1989

Beta 2-adrenoceptor-mediated increase in the slow inward calcium current in atrial cells.

The effects of procaterol (beta 2-adrenoceptor agonist) on the slow inward calcium current (Isi) were examined in single cells of guinea-pig heart. Procaterol increased Isi in atrial cells, in the presence of atenolol (beta 1-adrenoceptor antagonist). The effect was abolished by ICI-118551 (beta 2-adrenoceptor antagonist). However, procaterol did not modify the membrane currents in ventricular cells. These results suggest that beta 2-adrenoceptor agonists bind to beta 2-adrenoceptors in atrial cells and augment Isi, but beta 2-adrenoceptors are not present in ventricular cells.

Adrenergic alpha-Agonists↗
PubMed1989

Innervation of the arteriovenous anastomoses in the dog tongue.

Profiles of nerve plexuses in the arteriovenous anastomoses of the dog tongue were investigated by both transmission and scanning electron microscopy. Three-dimensional morphology of the vascular nerves was examined after removal of the connective tissue components by the HCl-hydrolysis method. Tight bending and a rich nerve supply were the most characteristic features of the anastomosing channels. The tunica media consisted of an outer circular layer of typical smooth-muscle cells and an inner region containing longitudinal plicae of ramified smooth-muscle cells. The tunica adventitia was exclusively occupied by nerve bundles; fibroblasts were poorly developed. Numerous nerve bundles of variable size were coiled around the anastomosing channels, and occasional bundles ran crosswise over the U-shaped bent vessels.

Animals↗
PubMed1989

Some aspects of Leucocytozoon caulleryi reinfection in chickens.

The role of first- and second-generation schizonts in acquired immunity to Leucocytozoon caulleryi in chickens was studied. The chickens, which had recovered from a primary infection with various doses of sporozoites at 22-95 days of age, were challenged with sporozoites. First-generation merozoites were found in all of the challenged chickens, but no second-generation merozoites and gametocytes were seen in 30 of 32 chickens challenged with sporozoites. Almost all of the chickens that had recovered from a primary infection with sporozoites showed complete resistance to reinfection, and those that had recovered from a primary infection with first-generation merozoites showed resistance to reinfection with sporozoites. These results indicate that the second-generation schizont of L. caulleryi appears to be more immunogenic than the first-generation schizont and that some immune factors acquired by the chickens in the second generation of schizogony may inhibit the development of second-generation schizonts.

Animals↗
PubMed1989

Transformation of oocysts from several coccidian species by heat treatment.

The transformation of sporocysts in oocysts of Eimeria caviae, E. intestinalis, E. nieschulzi, E. separata, E. tenella, Isospora canis, I. heydorni, and Toxoplasma gondii by heat treatment was examined. Fresh unsporulated oocysts from these species were heated at 50 degrees or 55 degrees C for less than 5 min and cultivated at 25 degrees C for 1 week. No transformation of sporocysts was observed in the sporulated oocysts following heating at 55 degrees C, but sporulated oocysts of Tyzzeria and Caryospora types were found in some I. canis and I. heydorni oocysts after heating at 50 degrees C followed by cultivation. A few sporulated oocysts of the Isospora type were observed in E. intestinalis oocysts after cultivation. All transformed sporulated oocysts contained eight sporozoites. In contrast, the number of sporocysts varied from two to 0. These results indicate that sporocyst formation in oocysts was affected by heat treatment. The relationship between the total numbers of sporozoites and sporocysts in the transformed oocysts was consistent with that of the "Octozoic" group classified by Hoare.

Animals↗
PubMed1989

[Dissolution and absorption behavior of meclizine dihydrochloride from soft gelatin capsules].

Two kinds of soft gelatin capsules containing meclizine dihydrochloride (MZ) were prepared by using a medium-chain length triglyceride as a base. One is a self-emulsifying type, and the other is an oil dispersing type. The release of MZ from soft capsules and its in vivo absorption behavior were examined and compared with those of a commercial tablet. The release of MZ from the self-emulsifying soft capsule which was only slightly affected by pH was greater than those from the oil dispersing soft capsule and commercial tablet. The serum levels of MZ after the administration of preparations orally to beagle dogs increased in the order of self-emulsifying soft capsule, commercial tablet, oil dispersing soft capsule. This result suggests that the self-emulsifying soft capsule is useful for the increase of the bioavailability of the drug.

Administration, Oral↗
PubMed1989

Serum parathyroid hormone concentration measured by highly sensitive assay in post-thyroidectomy hypocalcemia of patients with Graves' disease.

To investigate the role of parathyroid function in transient hypocalcemia after subtotal thyroidectomy for Graves' disease, the serum parathyroid hormone (PTH) concentration and nephrogenous (N) cAMP were measured in 16 patients before and after surgery. Serum PTH was measured with two commercially available kits (PTH-M, PTH-C), PTH-M is a recently developed highly sensitive assay using an antibody recognizing the mid-portion of human PTH and a synthetic 125I-tyr45-human PTH (43-68) as a radioligand. One of the 16 patients had severe clinical tetany and had a markedly lower PTH-M concentration and NcAMP after thyroidectomy. However, no significant change in serum PTH-M, PTH-C and NcAMP were observed in the other patients, although their serum calcium (Ca) concentrations decreased significantly. The Data were analyzed by dividing the patients according to the change in serum Ca or PTH. Serum PTH-M and PTH-C significantly decreased in 4 patients whose serum Ca clearly decreased after surgery. Serum Ca on the first postoperative day was significantly lower in patients whose serum PTH decreased after thyroidectomy than in patients whose serum PTH did not. Furthermore, the serum Ca concentration was significantly correlated with PTH-M, and with NcAMP on the third postoperative day. These data proved that hypofunction of the parathyroid gland is important in transient hypocalcemia after subtotal thyroidectomy for Graves' disease. The pathogenetic mechanism of transient hypocalcemia was discussed in comparison with the data from a patient who had overt parathyroid injury.

Calcium↗