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Biomedical subjects

J Kobayashi

Publications and source records attributed to J Kobayashi.

At least 415 records · Page 23Linked to original sources
PubMed1989

Geographutoxin-sensitive and insensitive sodium currents in mouse skeletal muscle developing in situ.

1. The whole-cell voltage-clamp technique was used to examine developmental changes of Na+ current properties in single fibres of mouse flexor digitorum brevis muscles developing in situ from birth to 20 days post-natal. 2. Geographutoxin II (GTX II), a novel polypeptide toxin from the marine snail Conus geographus, distinguished two different types of voltage-sensitive Na+ currents: GTX II-sensitive and GTX II-insensitive currents, which corresponded respectively to currents with high or low TTX sensitivity. 3. Voltage-dependent activation and inactivation of the GTX II-insensitive currents occurred at membrane potentials 10-20 mV more negative than those for the GTX II-sensitive currents. 4. The GTX II-insensitive current in fibres from mice older than 8 days inactivated more slowly than the GTX II-sensitive current. However, in fibres from younger mice, the two currents decayed with similar speed. 5. The mean specific Na+ conductance (gNa) for the total (GTX II-sensitive plus GTX II-insensitive) Na+ channels was 0.22 mS/muF at a Na+ concentration of 5 mM at birth. The total gNa increased 6-fold to 1.32 mS/muF during the first 20 days after birth. 6. The mean specific gNa for the GTX II-insensitive channels was 0.15 mS/muF at birth, remained at approximately the same level for the first 8 days, and then decreased progressively to become undetectable by day 16. 7. In muscle fibres denervated 12 days after birth, the GTX II-insensitive gNa increased over the next 8 days, whereas the total gNa increased less than normal. 8. By contrast, in fibres denervated on day 4, the total gNa increased more than normal in the following 8 days, and the GTX II-insensitive specific gNa increased above the level seen at birth. 9. Half-maximal activation and inactivation potentials of the total and the GTX II-insensitive currents shifted in the negative direction by 9-17 mV in the first 8 days after birth. 10. We conclude that the regulatory effects of innervation on the total gNa are either suppressive or enhancing depending on the stage of development. On the other hand, denervation elicits an increase in GTX II-insensitive Na+ currents at all ages studied.

Aging↗
PubMed1989

Quantitative evaluation of pulmonary regurgitation after repair of tetralogy of Fallot using real-time flow imaging system.

Real-time flow imaging of pulmonary regurgitation (PR) by two-dimensional pulsed Doppler echocardiography was performed in 34 patients after repair of tetralogy of Fallot. The right ventricle and pulmonary artery were demonstrated in the parasternal short axis view and PR flow was visualized. The image was frozen when the velocity of regurgitant flow was maximum at the level of the pulmonary valve. Pulmonary regurgitant area index (PRAI) was calculated from planimetric measurement of the area where PR flow was expressed. Grading of PR (1 to 3) was independently attempted according to the extension of PR flow detected in pulmonary artery by a range-gated pulsed Doppler echocardiography. PRAI (cm2/m2) was 0.36 +/- 0.29 (mean +/- standard deviation) in grade 1, 1.48 +/- 0.46 in grade 2, and 2.80 +/- 0.94 in grade 3. Severity of PR (grade 1 to 3) was also rated on the basis of the pulmonary arteriography and compared with PRAI. PRAI was 0.64 +/- 0.60 in grade 1, 1.07 +/- 0.63 in grade 2, and 2.21 +/- 1.67 in grade 3, respectively. RPAI showed strong correlation with pulmonary regurgitant fraction measured by videodensitometric study of right ventriculography (r = 0.84). Quantitative evaluation of PR using real-time flow imaging system is a reliable and useful method.

Adolescent↗
PubMed1989

Results of routine restaurant inspections can predict outbreaks of foodborne illness: the Seattle-King County experience.

To analyze the association between the results of routine inspections and foodborne outbreaks in restaurants, we conducted a matched case-control study using available data from Seattle-King County, Washington. Case restaurants were facilities with a reported foodborne outbreak between January 1, 1986 and March 31, 1987 (N = 28). Two control restaurants with no reported outbreaks during this period were matched to each case restaurant on county health district and date of routine inspection (N = 56). Data from the routine inspection that preceded the outbreak (for case restaurants) or the date-matched routine inspection (for control restaurants) were abstracted from computerized inspection records. Case restaurants had a significantly lower mean inspection score (83.8 on a 0 to 100 point scale) than control restaurants (90.9). Restaurants with poor inspection scores and violations of proper temperature controls of potentially hazardous foods were, respectively, five and ten times more likely to have outbreaks than restaurants with better results. Although this study demonstrates that Seattle-King County's routine inspection form can successfully identify restaurants at increased risk of foodborne outbreaks, it also illustrates that more emphasis on regulation and education is needed to prevent outbreaks in restaurants with poor inspection results.

Disease Outbreaks↗
PubMed1989

[Human mandibular movements during swallowing saliva. 1. Tooth contacts and rest position].

We investigated the swallowing of saliva on 11 adults with a normal tooth alignment and a normal occlusion. The envelope of sagittal incisal point movements of the mandible was analyzed by means of the infrared sensor system. Frankfurt horizontal plane was used as a reference plane. The following conclusions were obtained based on the experimental results. 1. The mean linear distance between retruded tooth contact position (RCP) and intercuspal position (ICP) was 1.35 mm. 2. The mean linear distance between most retruded tooth contact position during swallowing saliva (SRCP) and ICP was 0.13 mm. The ratio of SRCP to RCP was about 10 percent. 3. The rest position of the mandible induced by swallowing saliva (RP) was 1.05 mm apart from ICP. 4. The maximum interocclusal distance during a cycle of swallowing saliva (MOP) was 1.70 mm in the average of 11 subjects. RP and MOP were significantly different from each other in the average of 11 subjects. However, individuals whose RP and MOP were significantly different were 6 subjects of 11.

Adult↗
PubMed1989

[Mechanisms of bronchoconstriction induced by anaphylaxis in sensitized guinea pigs].

Anaphylactic reaction in sensitized guinea pigs is known to induce bronchoconstriction when an adequate amount of antigen is administrated. This phenomenon has been established as a model of bronchial asthma. To evaluate the mechanism of bronchoconstriction in anaphylaxis, we analyzed the change of endobronchial pressure in sensitized guinea pigs. Guinea pigs weighing 300-600 g were actively sensitized by intracutaneously administrated ovalbumin (10 mg). Two weeks later they were anesthetized and mechanically ventilated with a volume type Harvard respirator. Antigen was administrated intravenously and monitoring of endotracheal pressure and systemic blood pressure was performed. Drugs to modify these reactions were administrated intraperitoneally 30 minutes before antigen challenge. In the control group, the endotracheal pressure showed a curve with the first peak between 0.5 and 1.5 minutes after the antigen challenge. When cyclooxygenase inhibitor (indomethacin) was administered before the antigen, the first peak was markedly suppressed. However, the histamine (H1)-receptor blocker did not suppress the first peak. On the other hand when 5-lipoxygenase inhibitor (AA-861) was administered before the antigen, the increase of intratracheal pressure was suppressed between 2 and 4 minutes after the antigen challenge. The above results may suggest that the first peak of intratracheal pressure derives from bronchoconstriction caused by prostaglandins or thromboxanes, and that the increase of intratracheal pressure at between 2 and 4 minutes derives from bronchoconstriction caused by leukotrienes.

Anaphylaxis↗
PubMed1989

[Left ventricular volume characteristics and its relationship with right ventricle after repair of tetralogy of Fallot].

In order to study the left ventricular volume characteristics and right ventricular influence on left ventricle, cardiac catheterization and biplane cineangiography was performed in 61 patients after repair of tetralogy of Fallot. Preoperative left ventricular volume size was also measured in 25 patients. Postoperative left ventricular end-diastolic volume index (LVEDVI) was 93 +/- 22 ml/m2 (mean +/- standard deviation) and it was 140 +/- 29% of normal left ventricular volume. Left ventricular ejection fraction (LVEF) was 60 +/- 6%. Left ventricular size significantly increased from 109 +/- 25% to 140 +/- 23% of normal by corrective surgery (p less than 0.001). Left ventricular volume characteristics are correlated with right ventricle. LVEDVI increased with increasing right ventricular end-diastolic volume index (RVEDVI) and decreased right ventricular ejection fraction (RVEF). LVEDVI (ml/m2) = 60 + 0.29 RVEDVI (ml/m2), r = 0.52, p less than 0.001, LVEDVI (ml/m2) = 141 - 0.90 RVEF (%), r = -0.30, p less than 0.02. LVEF decreased with increasing RVEDVI and decreased RVEF. LVEF (%) = 68 - 0.075 RVEDVI (ml/m2), r = -0.51, p less than 0.001, LVEF (%) = 43 + 0.32 RVEF (%), r = 0.40, p less than 0.001. On the contrary there was no relationship between right ventricular volume characteristics and right ventricular systolic pressure. There were two cases whose LVEF was less than 50%. In one case right ventricular systolic pressure was as high as 98 mmHg. In the other patient RVEDVI was 299 ml/m2 (453% of normal right ventricular volume) because of severe pulmonary regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Acute massive mediastinal hemorrhage three weeks after mitral valve replacement in a patient with systemic lupus erythematosus].

Systemic lupus erythematosus (SLE) is one of the most common autoimmune diseases and patients suffering from this disease often died of massive hemorrhage. We report the case of a patient who died of acute massive hemorrhage three weeks after mitral valve replacement. The patient, a 42 year-old woman, had been diagnosed as having valvular heart disease at the age of 10. She underwent mitral commissurotomy at the ages of 18 and 32. SLE was diagnosed 8 years previously and corticosteroid therapy was initiated. The patient was experiencing exertional dyspnea again 1 year ago and mitral valve replacement was performed for recurrent stenosis. The postoperative course seemed to be uneventful, but on the 21st postoperative day, acute massive mediastinal hemorrhage occurred, and the patient eventually died of septicemia. Massive hemorrhage in SLE patients usually occur in the central nervous system or alimentary tract. However, bleeding can occur anywhere, so great care must be taken in regulating anticoagulant therapy.

Adult↗
PubMed1989

[Effects of thromboxane A2 synthetase inhibitor, DP-1904 on the action of vasoactive substances in guinea pig trachea and lung tissue strips].

Thromboxane A2 (TxA2) is a potent platelet aggregator and vascular or bronchial constrictor. DP-1904, a newly synthesized imidazol TxA2 synthetase inhibitor, is a potent and long-acting agent. The present investigation was conducted to explore the effect of DP-1904 on the contractile or relaxing responses in guinea pig trachea and lung tissue strips induced by various vasoactive substances. Fourteen guinea pigs, weighing 300-350 g, were sacrificed. Trachea and lungs were removed, cut spirally, set up in bioassay glass jackets and superfused with Krebs-Henseleit solution at 37 degrees C, saturated with oxygen and carbon dioxide. Contraction of tissues was detected by an isotonic transducer and displayed on a polyrecorder. Arachidonic acid-induced relaxing responses in guinea pig trachea strips were attenuated significantly by the continuous infusion of DP-1904 in a dose-dependent fashion. Arachidonic acid-induced contractile responses in guinea pig lung strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. Acetylcholine-, histamine- and prostaglandin F2 alpha-induced contractile responses in guinea pig lung and trachea strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. The above results suggest that DP-1904 might be a useful therapeutic agent for the treatment of chronic obstructive lung diseases.

Acetylcholine↗
PubMed1989

[Effects of thromboxane A2 synthetase inhibitor, DP-1904 on the action of vasoactive substances in rabbit blood vessel smooth muscle preparations].

Thromboxane A2 (TxA2) is a potent platelet aggregator as well as a vascular and bronchial constrictor. DP-1904, a newly synthesized imidazol TxA2 synthetase inhibitor, is a potent and long-acting agent. The present investigation was conducted to explore the effect of DP-1904 on the contractile responses in rabbit pulmonary artery and descending aorta strips induced by various vasoactive substances. Fourteen Japanese albino rabbits, weighing about 3 kg, were sacrificed. Rabbit pulmonary artery and descending aorta were removed, cut spirally, set up in bioassay glass jackets and superfused with Krebs-Henseleit solution at 37 degrees C, saturated with oxygen and carbon dioxide. Contraction of tissues was detected by an isotonic transducer and displayed on a polyrecorder. Arachidonic acid-induced contractile responses in rabbit pulmonary artery and descending aorta strips were attenuated significantly by the continuous infusion of DP-1904 in a dose-dependent fashion. Prostaglandin F2 alpha-induced contractile responses in rabbit pulmonary artery and descending aorta strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. Angiotensin II-induced contractile responses in rabbit pulmonary artery and descending aorta strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. Norepinephrine-induced contractile responses in rabbit pulmonary artery and descending aorta strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. The above results suggest that DP-1904 might be a useful therapeutic agent for treatment of pulmonary hypertension in patients with chronic obstructive lung diseases.

Animals↗
PubMed1989

[Effects of nicotine and cigarette smoke extracts on plasma level of complement C3a and C5a, thromboxane B2 and 6-keto PGF1 alpha in rabbits].

In the present investigation we measured plasma levels of complement C3a and C5a, thromboxane B2 (TxB2) and 6-keto PGF1 alpha in anesthetized rabbits by radioimmunoassay after the intravenous injection of nicotine and cigarette smoke extracts. Plasma levels of complement C3a in rabbits showed a significant increased and reached a maximum value 60 minutes after the intravenous injection of nicotine and cigarette smoke extract. Plasma levels of complement C5a in rabbits showed a significant increase and reached a maximum value 30 minutes after the intravenous injection of nicotine. Plasma levels of complement C5a in rabbits showed a significant increase and reached a maximum value 60 minutes after the intravenous injection of cigarette smoke extract. Plasma levels of TxB2 in rabbits showed a significant increase after the intravenous injection of nicotine and cigarette smoke extract. Plasma levels of 6-keto PGF1 alpha in rabbits did not show any change after the intravenous injection of nicotine and cigarette smoke extracts. The above results may suggest that the intravenous injection of nicotine and cigarette smoke extracts induces an increase of plasma levels of complement C3a and C5a and TxB2 in anesthetized rabbits.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[Noninvasive and quantitative evaluation of pulmonary regurgitation by pulsed Doppler echocardiography--a study in patients with tetralogy of Fallot after corrective surgery].

A noninvasive and quantitative evaluation of pulmonary regurgitation (PR) using pulsed Doppler echocardiography (PDE) was performed in 25 patients with tetralogy of Fallot (TOF) after corrective surgery. Considering a possibility of the presence of the difference in regurgitant flow velocity in pulmonary artery, four sampling points for detecting the pulmonary regurgitant flow were designed as follows: point 0 was positioned at the right ventricular outflow tract; point 1, at the pulmonary annulus; point 2, at mid-portion of the pulmonary trunk; point 3, at bifurcation of the pulmonary artery. The values of maximum Doppler shift determined by analysing the sonograms recorded at point 1, 2 and 3 were examined in comparison with the grades of PR estimated by pulmonary arteriography and the results obtained were as follows. In a retrospective study in 18 patients with PR, the values of maximum Doppler shift were highest at point 1, and followed by point 2 and point 3 in order (p less than 0.005), indicating that the velocity gradient of regurgitant flow existed in the pulmonary artery. The values of maximum Doppler shift were highest in the group of PR grade III estimated by pulmonary arteriography, and followed by the group of PR grade II and grade I in order. At point 2, the group of grade III-PR showed significantly higher Doppler shift than the group of grade I-PR (p less than 0.05). Following above data, a new criteria for estimating the severity of PR by PDE according to the velocity gradient of regurgitant flow in the pulmonary artery was proposed. In a prospective study in a separate group of other 7 patients, the grade of PR estimated by PDE corresponded well with these of pulmonary arteriography, with a significant Spearman rank correlation coefficient (rs = 0.90, p less than 0.01). An experimental study using a dog with surgically induced PR of different grades confirmed the presence of higher Doppler shift in pulmonary artery corresponding to the grade of PR. These results indicated the usefulness of a newly proposed method evaluating PR by PDE applying a concept of Windkessel model for PR regurgitant flow.

Adolescent↗
PubMed1989

[A radical operation of Chiari's disease using the internal shunt tube of the inferior vena cava].

A case with the Budd-Chiari syndrome due to the right hepatic occlusion who was successfully operated by using the internal shunt tube of the inferior vena cava was reported. The patients was 33 year old male. Midsternal incision and right subcostal oblique incision were made and the internal shunt tube was inserted through the right auricle to the inferior vena cava. The hepatic vein was approached through the longitudinal suprahepatic caval venotomy. Then membranous obstruction in the right hepatic vein ostia was resected. Mesenteric venous pressure dropped immediately from 360mm H2O to 160mm H2O by direct manometry. All the blood bled from the right hepatic vein was transfused through the internal shunt tube to the right atrium. The patient tolerated the procedure and his postoperative course was free from the complication. The resected membrane was congenital anomaly and an operative liver biopsy was demonstrated the evidence of congestive liver with fibrosis.

Adult↗
PubMed1989

[Evaluation of total cavopulmonary shunt operation from late results].

Total cavopulmonary shunt was performed in 6 patients (pts) with single ventricle and common atrioventricular valve (CAVV) with left isomerism between 1978 and 1987. Four patients survived including 1 with CAVV-replacement and follow-up period ranged from 1.5 to 10 years. The first pt tolerated a pregnancy and re-replacement of CAVV. All 4 pts showed significant improvements in symptom. The arterial oxygen saturation was around 90% early postoperatively, but 2 pts developed pulmonary arteriovenous fistula with decreased arterial oxygen saturation. This operation can be indicated in left isomerism with low operative risk, and also may be applied in those with CAVV regurgitation although the risk becomes high. PAVF is a matter of concern in the late follow-up.

Adult↗
PubMed1988

Alpha-adrenoceptor blocking action of hymenin, a novel marine alkaloid.

In the rabbit isolated aorta, hymenin (10(-6) M), a novel marine alkaloid, caused a parallel rightward shift of the dose-response curve for norepinephrine without affecting that for histamine or KCl, suggesting that hymenin is a competitive antagonist of alpha-adrenoceptors in vascular smooth muscles.

Adrenergic alpha-Antagonists↗
PubMed1988

A familial hyperalphalipoproteinemia with low uptake of high density lipoproteins into peripheral lymphocytes.

A patient with an extremely high level of high density lipoprotein (HDL)-cholesterol and HDLc-like particles in the serum is discussed. The patient was a 46-year-old female with a serum total cholesterol concentration of 382 mg/dl and HDL-cholesterol level of 214 mg/dl. The HDL-cholesterol levels of her mother, brother, sister and 2 of her daughters were 82 mg/dl, 82 mg/dl, 74 mg/dl, 82 mg/dl and 82 mg/dl, respectively (mean HDL-cholesterol levels of control subjects: 52 +/- 6 mg/dl in males and 55 +/- 8 mg/dl in females). Her serum apolipoprotein A-I and E levels were elevated. Zonal ultracentrifugal analysis of her serum lipoproteins showed that the increased level of HDL-cholesterol was mainly due to HDL2; HDLc-like particles were also recognized between the LDL and HDL fractions. The incorporation of the patient's HDL and HDLc-like particles into cultured HepG2 cells was almost the same as that of HDL (1.063 less than d less than 1.21) from normal control serum. The incorporation of normal control HDL into the patient's peripheral blood lymphocytes was markedly less than that into lymphocytes from normal controls. These findings are discussed in terms of the reason for hyperalphalipoproteinemia in this patient.

Animals↗
PubMed1988

The mechanism of the inotropic action of striatoxin, a novel polypeptide toxin from a marine snail, in isolated cardiac muscle.

1. Striatoxin (StTX), a novel polypeptide from a marine snail, caused a dose-dependent increase in contractility in the isolated atria of guinea-pig and rat in the concentration-range of 2 x 10(-9) to 3 x 10(-8)M and 3 x 10(-6)M, respectively. 2. In guinea-pig atria, the StTX-induced inotropic effect was inhibited by tetrodotoxin but not by cimetidine or chlorpheniramine. Practolol, propranolol or reserpine caused only partial block of this inotropic action. 3. In isolated single cells from rat hearts, StTX caused an increase in the degree and the rate of contraction. 4. In guinea-pig atria, StTX provoked action potentials with a plateau phase of long duration without affecting the maximum rate of rise, the amplitude of action potential and the resting membrane potential. This prolongation was also reversed by tetrodotoxin. 5. In guinea-pig cardiac myocytes, whole-cell patch-clamp experiments showed that StTX slowed Na channel inactivation without affecting the time course of channel activation. The voltage dependence of Na currents was not altered by StTX. 6. The residual currents, but not peak currents were markedly enhanced by StTX. 7. These results suggest that StTX causes prolongation of the action potential duration probably due to slowed inactivation of Na inward currents and enhanced residual currents and that this may result in an increase in Ca2+ availability in cardiac muscle cells. This could explain the cardiotonic action of StTX.

3',5'-Cyclic-AMP Phosphodiesterases↗