Search PubMed⌕ Search

Biomedical subjects

T Kubo

Publications and source records attributed to T Kubo.

At least 919 records · Page 51Linked to original sources
PubMed1983

Effects of serotonin and some other neurohumoral agents on adrenergic neurotransmission in spontaneously hypertensive rat vasculature.

The effects of serotonin (5HT), acetylcholine (ACh), histamine and dopamine on the pressor responses of the mesenteric vasculature were examined in view of their potential role in neuromodulation. The responses to periarterial sympathetic nerve stimulation (NS, 8 Hz, 2 msec, 30 sec) and to exogenous norepinephrine (NE, 0.2 nmol) were compared between spontaneously hypertensive rats (SHR) and the control Wistar Kyoto rats (WKY). In both WKY and SHR, ACh (3-30 nM), histamine (0.3-3 microM) and dopamine (0.3 microM) attenuated the NS-induced vasoconstrictor response as much as the NE-induced response, indicative of predominance of postsynaptic inhibition. 5HT (10-100 nM) potentiated the vasoconstrictor responses to NS significantly less than that to NE in WKY, suggestive of presynaptic inhibition. Such difference was absent in SHR. These results suggest that the presynaptic inhibition of vascular adrenergic neurotransmission by 5HT is diminished in SHR, and this may contribute to the elevated blood pressure.

Acetylcholine↗
PubMed1983

Uneventful pregnancy and delivery in a case of multiple peripheral pulmonary stenoses.

The first case of multiple peripheral pulmonary stenoses undergoing uneventful pregnancy and delivery is described. The course of pregnancy in a patient with peripheral pulmonary stenoses may generally be uneventful, because increased pulmonary blood flow in pregnancy may cause little influence on pulmonary circulation in this disease by the same mechanism as in pulmonary stenosis, the course of which is known to be uneventful during pregnancy.

Adult↗
PubMed1983

[Four cases of cerebral venous angioma--with special reference to its surgical indication and CT diagnosis].

Four cases of venous angioma, one cerebral and three in the cerebellum, are reported. Case 1. A 50-year-old woman who had a sudden attack of headache and disorientation was admitted to the Mitsui Memorial Hospital. Neurological examination revealed slight disorientation, mild motor aphasis and right hemiparesis. Plain CT scan on admission showed a left frontal hematoma. Left cerebral angiomas demonstrated a caput-Medusae-like lesion which consisted of numerous small veins and drained into one single enlarged vein. Enhanced CT scan taken 12 days after the attack demonstrated a linear enhancement next ot the hematoma. Left frontal craniotomy was performed, and the hematoma was evacuated. In the next step, coagulation and resection of the major part of the angioma was attempted. However, this caused significant swelling of the adjacent brain and the angioma had to be resected totally including intervening normal cerebral tissue. Postoperatively, the patient became worse with significant hemiparesis and severe motor aphasia. After intensive rehabilitation treatment, she recovered gradually and was discharged on foot with moderate speech disturbances. Histological examination revealed a typical venous angioma with hyalinization of vessel wall. Case 2. A 55-year-old woman with a 9 year history of vertigo and headache was admitted to our hospital because of sudden onset of numbness in her right lower limb. Enhanced CT scan revealed a small nodular high density lesion and an old hematoma in the right cerebellar hemisphere. Vertebral angiograms demonstrated a single abnormal vein with some small veins in the right cerebellum. Right suboccipital craniectomy was performed and the blood clot was removed. The abnormal veins were electro-coagulated. The postoperative course was uneventful and the patient was discharged with no neurological deficit. Case 3. A 31-year-old man was admitted to our department with 9 month history of nausea and vertigo attack. Enhanced CT scan demonstrated a large nodular high density lesion in the left cerebellar hemisphere. Vertebral angiograms showed a typical caput-Medusae-like venous angioma. The patient had no evidence of hemorrhage and was discharged without surgery. Case 4. A 36-year-old man who had two attacks of nausea and headache was admitted to the Mitsui Memorial Hospital. Enhanced CT scan showed a linear high density lesion in the right cerebellar hemisphere. Vertebral angiograms disclosed a typical venous angioma in the right cerebellum. This patient also had no attack of bleeding and was discharged without operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Modification of sympathetic nerve stimulation frequency-response relationship in rabbit ileum by guanethidine, bretylium and tetracaine.

Effects of low concentrations of guanethidine, bretylium and tetracaine were comparatively studied with regard to inhibitory responses of rabbit ileum to periarterial nerve stimulation at 5, 10 and 20 Hz. Guanethidine 2 X 10(-7) to 10(-6) M and bretylium 3 X 10(-6) to 3 X 10(-5) M dose-dependently and preferentially reduced responses to lower frequencies, whereas tetracaine 10(-5) to 3 X 10(-5) M reduced responses, in a dose- and frequency-dependent manner. In conclusion, the mode of adrenergic neuron blocking action of guanethidine and bretylium differs from that of local anesthetics.

Animals↗
PubMed1983

[A case of an incompletely duplicated ventral urethra].

A ventral incomplete duplicated urethra was found in a 20-year-old male. The accessory urethra lay ventral to and in parallel with the normal urethra. The external orifice of the accessory urethra was also ventral to the orifice of the normal urethra in the glans. On the other hand, the accessory urethra was closed near the bulbar region, and an abscess was found at the dead end. The accessory urethra, which was 9 cm long, was surgically removed. Histopathologically, the luminal surface was covered with a stratified squamous epithelium; and, smooth muscle and spongy tissue were observed around the accessory urethra. The classification of the duplicated urethra is discussed.

Adult↗
PubMed1983

[Ultrastructural studies of healing process of injured articular cartilage].

This study was undertaken to investigate the healing process and the nature of the repaired tissue of injured articular cartilage. Full-thickness defects were made in the articular cartilage of the femoral condyles of 48 immature rats, and were examined by using light and transmission electron microscopes from one to 48 weeks after the injury. Under the light microscope, toluidine blue metachromasia was demonstrated in the deep matrix at 4 weeks after the injury. The repaired tissue was similar to the articular cartilage in controls at 12 weeks after the injury, but decreased number of cells and irregular surface were recognized in the specimen taken at 48 weeks after the injury. By electron microscopic examinations, at 12 weeks after the injury, cells in the repaired tissue were indistinguishable from chondrocytes, and the tidemark showed a fine structure similar to that in the articular cartilage in controls where many electron dense particles were observed. Collagen fibrils in the superficial layer were arranged in parallel to the articular surface. Three dimensional meshwork of collagen fibrils was also recognized in the intermediate and deep layers, but was inferior to that in the articular cartilage in controls. At 48 weeks after the injury, the surviving cells in the repaired tissue contained deposits of glycogen, large lipid droplets and vacuoles. Amianthoid change and fibrous long-spaced collagen were occasionally observed in the matrix. Collagen fibrils in the areas with poor cell population were smaller in diameter and loosely arranged. The above findings indicate that the anomalous arrangement of collagen fibrils is a main cause for the weakness of the repaired tissue to the mechanical load, resulting the degeneration.

Animals↗
PubMed1983

[Comparison of variability (STV and LTV) indices by computer-simulated data].

Many investigators have proposed their own formula for quantitative evaluation of STV (short term variability) and LTV (long term variability). There has even been confusion over the definition itself of STV. We compared those indices by using 'beat to beat interval' computer-simulated series and found that there is little difference between the STV indices. According to the definition of STV by the Japan Society of Obstetrics and Gynecology, it is the variance in beat to beat difference, which is determined by the variance in beat to beat intervals and the autocorrelation function of the same intervals. For all the 2,500 combinations of the variability and the autocorrelation, normal random interval series were generated by the computer and five indices (Dalton, Cabal, Yeh, Heilbron and de-Haan) were compared with calculated index values using these interval series. Assigning the variability and the autocorrelation to the X-axis and the Y-axis respectively, the Z-axis was used to indicate the value of the STV. Five curved surfaces thus formed have a similar shape, which shows us that these STV indices behave the same way in accordance with the change in STV. Further, the study of LTV indices with the same simulated data showed that Yeh's LTV index indicates only the variability but has no relation-ship with the autocorrelation and both de-Haan and Heilbron's LTV indices represent the variability and the autocorrelation. However, they increase as the autocorrelation increases unlike the STV indices.

Computers↗
PubMed1982

Presynaptic dual inhibitory actions of guanabenz on adrenergic transmission.

Actions of guanabenz, clonidine and guanethidine on adrenergic transmission were studied in rabbit atria and ilea with intact nerves. While guanabenz 3 X 10(-6) M and clonidine 3 X 10(-7) M inhibited to a similar degree atrial positive chronotropic responses to nerve stimulation at 2 Hz, no inhibition was seen at 10 Hz. Phentolamine 3 X 10(-6) M completely antagonized the inhibition by clonidine, but a partial antagonism was seen against guanabenz. Cocaine 10(-5) M prevented the phentolamine-resistant inhibition by guanabenz. Guanethidine 10(-5) M inhibited the responses to 2 and 10 Hz. In ilea, guanabenz 10(-5) M inhibited frequency-independent relaxation responses to 2-20 Hz. Clonidine 10(-5) M inhibited preferentially the responses to lower frequencies. After the temperature of the bathing solution was kept at 4 degree C during the period of drug application, guanabenz no longer produced an inhibition of the transmission, whereas clonidine produced the usual inhibition. Thus, guanabenz appears to have both presynaptic alpha-receptor stimulating and adrenergic neuron blocking actions.

Animals↗