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Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 523 records · Page 29Linked to original sources
PubMed1991

Hepatic vascular exclusion as a model for complete and stable hepatic ischemia in dogs.

In order to confirm a complete ischemia model, 1-hour warm hepatic ischemia by hepatic vascular exclusion (HVE) was studied in dogs, in comparison with that by inflow occlusion (IOC) only. The splanchnic venous bed and/or infrahepatic inferior vena cava were decompressed by a centripetal pump-driven venovenous bypass. Indocyanine green retention test revealed no hepatic blood flow in the HVE model during ischemia, while hepatic blood perfusion was still present in the IOC model. All 5 of the IOC dogs survived more than 7 days after revascularization, while 4 of the 5 HVE dogs died within 9 h. After the induction of hepatic ischemia, lactate increased in both HVE and IOC dogs. After revascularization, transaminases and guanase were elevated, the arterial ketone body ratio (acetoacetate/3-hydroxybutyrate) decreased and the serum lactate accumulated more in HVE dogs than in IOC dogs. The hepatic redox state of IOC dogs was significantly decreased by additional clamping of the inferior vena cava. It is concluded that the HVE model with a pump-driven active bypass provides complete and stable hepatic ischemia, resulting in greater deterioration of hepatic cellular functions; hence it is more suitable as a model of complete hepatic ischemia than the IOC one.

Animals↗
PubMed1991

Studies on glycolipids. III. Glyceroglycolipids from an axenically cultured cyanobacterium, Phormidium tenue.

Seven new monogalactosyl diacylglycerols (1-7) and six new digalactosyl diacylglycerols (11-16) were isolated from an axenically cultured cyanobacterium, P. tenue. Their structures were elucidated on the basis of physicochemical evidence and the results of enzymatic hydrolysis using a lipase (from Rhizopus arrhizus). Comparison of antialgal activity for P. tenue between monogalactosyl diacylglycerols (1-8) and digalactosyl diacylglycerols (11-19) revealed that the former showed more potent activity than the latter.

Cyanobacteria↗
PubMed1991

A sheep survived for 48 days with the biventricular bypass type total artificial heart.

A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.

Animals↗
PubMed1991

Regulation of vascular compliance and stress relaxation by the sympathetic nervous system.

We measured the changes in central venous pressure (CVP) and circulating blood volume (CBV) in dogs consequent to fluid infusion under halothane anesthesia, and compared the CVP and CBV responses to those obtained after blocking the autonomic nervous system by total spinal anesthesia (TSA) and stimulating the alpha receptor with methoxamine (MTX). Under TSA, the change in CVP consequent to fluid infusion was less than that under halothane anesthesia, while with MTX, the change in CVP was larger than that under halothane anesthesia. The recovery time of CVP response toward the baseline level after the end of fluid infusion was fastest under halothane anesthesia, while the recovery time of CVP was two times longer under TSA and MTX. Based on the relationship between changes in CVP and BV, we quantified effective vascular compliance and stress relaxation using mathematical analysis. The effective vascular compliance increased to 13.3 +/- 3.2 ml.mmHg-1.kg-1 under TSA as compared to 5.6 +/- 0.3 ml.mmHg-1.kg-1 under halothane anesthesia, and it decreased to 2.6 +/- 0.2 ml.mmHg-1.kg-1 with MTX. Stress relaxation was determined as the time constant in the unit response of CVP. The time constant for stress relaxation was 39 +/- 7 min under halothane, 74 +/- 12 min with TSA, and 92 +/- 25 min with MTX. These results suggest that the autonomic nervous system modifies cardiac preload by changing effective vascular compliance and stress relaxation.

Anesthesia, Spinal↗
PubMed1991

Partial corpus callosotomy beneficial for Lennox-Gastaut syndrome--report of two cases.

Seizures in patients with Lennox-Gastaut syndrome are very resistant to drug therapy. Division of the anterior half of the corpus callosum was performed in two patients with Lennox-Gastaut syndrome incapacitated by frequent atonic seizures leading to sudden falls. Postoperatively, the atonic seizures were completely eliminated and their mental reactivities remarkably improved. It is clear that they have benefited from a lower frequency of seizures and reduced dosages of anticonvulsant medication, which outweight the acquired disabilities.

Adult↗
PubMed1991

Spontaneous intracerebral hemorrhage in cases of severe angiospasm following ruptured aneurysm--a pathological study.

Eleven patients with a history of moderate or severe angiospasm following ruptured cerebral aneurysm developed spontaneous intracerebral hemorrhage between 31 and 111 months after aneurysm surgery. In all cases, hemorrhage occurred in the ipsilateral hemisphere to the original aneurysm. In nine patients, the hematoma was surgically evacuated and bleeding perforating arteries were resected for histological examination. Computed tomographic scans showed the hematomas to be unusually extended compared to those after hypertensive intracerebral hemorrhage. The histological examination showed various degenerative changes in the elastic lamina and media of the perforating arteries, even though most patients were young and normotensive. These findings suggest that patients who have suffered severe cerebral angiospasm may have a higher risk for subsequent development of intracerebral hemorrhage than those without prior angiospasm.

Aged↗
PubMed1991

Effect of intracisternal injection of endothelin-1 on regional cerebral blood flow in cats.

The effect of endothelin-1 on regional cerebral blood flow (rCBF) was investigated in adult mongrel cats. Endothelin-1 was injected into the cisterna magna and rCBF was measured by the hydrogen clearance method before and every 30 minutes for 180 minutes after the injection. Endothelin-1 (10(-11) mol and 10(-9) mol) induced a significant decrease in rCBF and an increase in arterial pressure. The effects of endothelin-1 on rCBF and arterial pressure were mediated, at least in part, by Ca2+, because pretreatment with intracisternally injected nicardipine prevented the changes. Cerebral angiograms obtained before and after endothelin-1 injection demonstrated severe constriction of the basilar artery, but constriction of the internal carotid and middle cerebral arteries was mild. Since the rCBF measured was in the territory of the middle cerebral artery, the decrease in blood flow was probably not solely due to the artery constriction. Other mechanisms such as arteriole constriction and/or regulation of rCBF by the central nervous system may also occur.

Animals↗
PubMed1991

Coronary vasospasm following subarachnoid hemorrhage as a cause of stunned myocardium. Case report.

A patient with subarachnoid hemorrhage was found to have electrocardiographic abnormalities resembling an acute myocardial infarction as well as left ventriculographic findings of cardiac dysfunction. These cardiac abnormalities resolved following surgical clipping of the aneurysm and the patient recovered well from the operation. She died 2 months later from cancer and a postmortem examination at that time revealed no evidence of myocardial necrosis. In this report, the authors discuss coronary vasospasm and reversible postischemic "stunned myocardium," a condition that has not been considered previously in relation to subarachnoid hemorrhage.

Aged↗
PubMed1991

Expression, localization, and function of an N-terminal half fragment of the rat Na,K-ATPase beta-subunit in HeLa cells.

The N-terminal half of the beta-subunit of rat brain Na,K-ATPase was expressed in HeLa cells transfected with the plasmid pSV2TKneo beta N containing the truncated beta-subunit cDNA to study the assembly and transport of alpha-beta complex. Immunoprecipitation from extracts of metabolically labeled transformed cells demonstrated that the truncated beta-subunit polypeptide (beta N) was neither transported to the plasma membrane nor assembled into an alpha-beta complex with the endogenous alpha-subunit. Cell fractionation experiments showed that the beta N truncated subunit remained unassembled within rough microsomes, suggesting that it never exited from the endoplasmic reticulum (ER). The assembly of the endogenous alpha-and beta-subunits in the beta N-expressing cells was significantly inhibited compared with control cells or with the transformants that did not express the beta N. These results suggest that the N-terminal portion of the beta-subunit interferes with the normal assembly of the endogenous complex which normally takes place in the ER.

Animals↗
PubMed1991

[Sequential changes in content of excitatory amino acids in the epileptic focus during seizure].

Recently much attention has been paid to excitatory amino acids in seizure susceptibility and induction. In order to examine the relationship between epilepsy, especially seizure induction, and excitatory amino acids, we examined sequential change in content of excitatory amino acids in the epileptic focus by microdialysis system in a cat amygdaloid kindling model. Fifteen crossbred adult cats divided into three groups: a sham operation group (Sh) as the control, just after stage 4 group (S4), and just after stage 6 seizure group (S6). Under halothane anesthesia, Microdialysis probe was inserted to the kindled focus, the right amygdala, and glutamate and aspartate contents of extracellular fluid were measured from 15 minutes prior to 30 minutes after seizure by high performance liquid chromatography (HPLC). The probe was perfused with artificial cerebrospinal fluid at a flow rate of 2 microliters/min for 5 minutes. Before seizure, glutamate and aspartate concentration showed no significant changes in the S4 and S6 group compared with the Sh group. But after seizure, glutamate concentration was significantly higher in the S4 and S6 group temporally, while aspartate concentration was higher only in the S6 group temporally. Based on the results that the release of glutamate and aspartate do not change in seizure susceptibility, that glutamate is released in partial seizure, and that glutamate and aspartate are released in generalized seizure from the epileptic focus, excitatory amino acids are involved in seizure induction in a cat amygdaloid kindling.

Amino Acids↗
PubMed1991

[The effect of repeated occlusions of the middle cerebral artery on pial arterial behavior and cerebral structure].

Temporary clipping of the major arterial trunk is a very important maneuver to control excessive unexpected bleeding during a neurosurgical operation, but repeated temporary clippings sometimes give rise to severe neurological deficits after surgery. In clinical practice, a major stroke can occur after many transient ischemic attacks without distinct angiographic occlusion. To confirm and explain these clinical experiences, the present study was performed. First, 20-min, 30-min and 1-h occlusion of the middle cerebral artery was performed in each of 5 cats, and pial arterial behavior, cerebral edema and infarction were observed. In the 20-min occlusion group, no abnormal change was found 5 hours after recirculation. In the 30-min occlusion group, cerebral edema was present in 10.5 +/- 4.2% of the hemisphere, but no infarction was observed, and pial arterial caliber remained in a 10% dilated state throughout the experimental periods. In the 1-h occlusion group, cerebral edema was present in 41.2 +/- 7.5% of the hemisphere and infarction was found in 34.5 +/- 9.5%. Pial arteries returned to a 20% dilated state but redilated by 45% at the end of experiment. As the second experiment, three 20-min occlusions at 1-h interval and two 30-min occlusions at 1-h interval were performed in each 10 cats. Pial arteries had dilated by 40% after release of the last occlusion in both groups. The extent of cerebral edema was 19.5 +/- 8.1% of hemisphere in the 20-min occlusions group and 36.6 +/- 9.7% in the 30 min occlusions group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Magnetic resonance imaging of skeletal muscle in patients with Duchenne muscular dystrophy--serial axial and sagittal section studies].

Magnetic resonance imaging of skeletal muscles in thirteen patients with Duchenne muscular dystrophy was performed to estimate pathological changes. Serial axial and sagittal sections of the right lower extremity were recorded. In the early stage, the T1 values of gastrocnemius and soleus muscles were slightly lower than the control values, and in the late stage, the values were much lower in all muscles examined. In sagittal sections, the gastrocnemius muscles in the early stage showed a high density area at the distal region adjacent to soleus muscle, and the soleus muscle showed a high density area adjacent to the gestrocnemius muscle. In serial axial sections, high density areas of the anterior and posterior tibialis muscles appeared first at their proximal and peripheral regions. It was concluded that the sequence of appearance of pathological changes was different not only among individual muscles but also among various regions of each muscle; the high density changes appeared first at myotendon junctions.

Adolescent↗
PubMed1991

[Serum antibodies to Legionella pneumophila by indirect immunofluorescent antibody test in 269 hemodialysis patients and 353 healthy subjects].

Serum antibodies to Legionella pneumophila serogroup I-VI were determined by indirect immunofluorescent antibody test in 269 hemodialysis patients and compared to 353 so called healthy subjects. Antigen suspension was prepared by incubation on B-CYE agar and adding formalin solution, then fixed on a micro slide glass, and reacted with serial serum dilutions. FITC-labeled goat antihuman immunoglobulin was added as a second antibody. 273 (77.3%) cases of control group had a titer of less than 1:4, 6 (1.7%) cases had a titer of 1: 32, and none had a titer of greater than or equal to 1: 64. There was no significant difference in sex and age. 173 (64.3%) hemodialysis patients had a titer of less than 1: 4, 13 (4.9%) cases had a titer of greater than or equal to 1: 64, and 5 (1.9%) cases had a titer of 1: 128, 42 (43.8%) of 96 cases who showed a titer of greater than or equal to 1: 4 had antibodies to Legionella pneumophila serogroup I. The titer in hemodialysis patients were higher than control group (p less than 0.005). The results of this study suspected that acute feverish disease and pneumonia of compromised host such as hemodialysis patients should be always thought of Legionnaires' infection.

Adult↗
PubMed1991

[Comparison of noninvasive techniques in evaluation of the Björk-Shiley and the St. Jude Medical valve prostheses in mitral position].

Pressure gradients and left ventricular function were assessed by Doppler echocardiography in 50 patients with Björk-Shiley mitral valve and 50 patients with St. Jude Medical valve prosthesis. There was correlation between pressure gradient and valve size, and between effective valve orifice area and valve size for St. Jude Medical valve. These correlations were not found in Björk-Shiley valve. Clinical improvement and cardiac function were quite satisfactory in 20 patients with Björk-Shiley valve and in 32 patients with St. Jude Medical valve whose pressure gradients were less than 10 mmHg. Twenty eight of 50 patients with Björk-Shiley valve and 42 of 50 patients with St. Jude Medical valve showed good response to the exercise test. Eight patients underwent reoperation because of unacceptably high gradient caused by thrombus and pannus formation. The patients who show high pressure gradient across the valve prosthesis should be followed up cautiously.

Cardiac Volume↗
PubMed1991

[Pharmacokinetical and clinical study of cefpirome in children].

This study describes the pharmacokinetic characteristics and clinical usefulness of cefpirome (CPR) in children. Mean half-lives of 20 mg/kg and 40 mg/kg of CPR injected intravenously in one shot were 1.18 and 1.34 hours, respectively, and their mean recovery rates into urine were 69.8 and 72.2%, respectively. Minimum inhibitory concentrations of CPR against Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Escherichia coli and Haemophilus influenzae were the same as or lower than those of ceftazidime. CPR was clinically effective in 14/15 of patients with bacterial infections; 8/9 of pneumonia, 2/2 of bronchitis, 1/1 of pharyngitis, 1/1 of tonsillitis, 1/1 of osteomyelitis, 1/1 of urinary tract infection. No clinically overt side effects of CPR were found, while an increase of eosinophils in blood was observed in 2 cases, and an increase of platelet in blood in 1 case and an elevation of serum GPT activity in 1 case were also observed. These findings indicate that CPR is useful for the treatment of bacterial infections in children.

Adolescent↗
PubMed1990

Sex hormone receptors in human thyroid tissues.

The behavior of sex hormone receptors was studied in the cytosol of thyroid tissue samples in order to clarify the effects of sex hormones on diseases of the thyroid. Androgen receptor (AR), estrogen receptor (ER), and progesterone receptor (PgR) were assayed using the dextran-coated charcoal (DCC) method and analyzed by the method of Scatchard. Androgen receptor, ER, and PgR were negative in all of the cytosol prepared from normal thyroid tissues. However, the positive rates for the receptors in the neoplastic and nonneoplastic tissues were 22% for AR, 29% for ER, and 18% for PgR. Especially, the incidence of ER was significantly higher in neoplastic lesions than normal tissues. These data suggest that sex hormones, especially estrogen, may play a role in diseases of the thyroid.

Age Factors↗