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Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 757 records · Page 42Linked to original sources
PubMed1994

Traumatic intracranial foreign body embolization--case report.

A 27-year-old male presented with intracranial embolization due to accidental penetration of his neck by an iron fragment at work. Cerebral angiography revealed foreign body embolization of the left middle cerebral artery. The foreign body was successfully removed via craniotomy and arteriotomy. The extended period from onset to surgical treatment prevented acute hemodynamic reconstruction. However, he had good collateral circulation and was discharged with mild hemiparesis and moderate motor aphasia. The possibility of intracranial embolization should be considered in patients presenting with penetrating injury of the neck.

Adult↗
PubMed1994

Acellular and cellular hemoglobin solutions as vasoconstrictive factor.

The inhibitory effects of acellular and cellular hemoglobin (Hb) solutions on endothelium-dependent vasorelaxation were investigated in rabbit thoracic aortic strips. As acellular Hb solutions, 2,3-diphosphoglycerate (DPG)-depleted Hb and pyridoxylated Hb were examined. Cellular Hb solutions included washed human fresh red cells and liposome Hb encapsulated with pyridoxal-5'-phosphate (PLP). The tissues were precontracted with phenylephrine (PE), after which acetylcholine (ACh) was added to elicit a steady-state relaxation. Acellular Hb solutions cumulatively reversed ACh-induced relaxation, and these inhibitory effects reached a plateau at 10 micrograms/ml. Increasing oxygen affinity by pyridoxylation had little effect on this. In contrast, both red cells and liposome Hb solution showed moderate inhibitory effects, and they reached a plateau at 1 mg/ml. These findings indicate that acellular Hb solutions are more potent inhibitors than cellular Hb solutions by a factor of about 100, and that the encapsulation of Hb is a preferable method to mimic the red cell.

2,3-Diphosphoglycerate↗
PubMed1994

The quality control of stroma-free hemoglobin: lysophosphatidylcholine, a component of stromal phospholipids, as candidate vasoconstrictive factor.

We characterized stromal phospholipids in stroma-free hemoglobin (SFH) by normal-phase and cation-exchange HPLCs, and found that SFH contained not only four phospholipids which were the major constituent classes in membrane, but also several peaks which were not yet identified. The residual amounts of these lipids in SFH were changed with storage of red cell concentrates. The four major phospholipids decreased concomitantly with storage, whereas the unidentified peaks increased after 21 days and then decreased after 48 days. We also found that SFH contained lysophosphatidylcholine (LPC) at 5.71 micrograms/ml, which was the deacylated metabolite of phosphatidylcholine (PC). These results suggest that stromal phospholipids are degradable. Since LPC is known to be capable of producing a defect in endothelium-dependent arterial relaxation, we next examined the effect of stromal lipids on vascular tone in rabbit thoracic aortic strips. Preincubation with the crude lipid extract or the LPC purified from SFH by TLC significantly inhibited acetylcholine (ACh)-induced relaxation in phenylephrine (PhE)-precontracted tissues. These observations have led to the proposal that LPC, a component of stromal phospholipids, induces vasoconstriction as a result of inhibition of endothelium-dependent vasorelaxation.

Animals↗
PubMed1994

The inhibitory action of lead on mechanical responses of the proventricular smooth muscle in the chick.

The purpose of the present experiments was to examine the mechanism of the proventricular dilatation caused by lead in the isolated vagus nerve-proventricular smooth muscle preparation of the chick. Lead caused dose- and time-dependent inhibition of contractions induced by vagal stimulation, transmural stimulation and externally applied acetylcholine (ACh). Vagally evoked contraction was much more sensitive to the inhibitory action of lead than the contractile response to ACh. The lower the frequency of transmural stimulation, or the lower the concentration of ACh was applied, the greater the inhibitory action of lead on the evoked smooth muscle contraction. The results suggest that proventricular impaction occurring in lead poisoning results from the pre- and post-synaptic inhibition of the vagus nerve-smooth muscle transmission.

Animals↗
PubMed1994

[Multiple cavernous angiomas accompanied with a convexity meningioma: a case report].

We reported a rare case of multiple cavernous angioma accompanied with a convexity meningioma. A 41-year-old female developed generalized convulsion on October 8, 1985. Plain computed tomography (CT) scan revealed a round heterogeneous density mass in the right parietotemporal region, which was homogeneously enhanced. Angiography demonstrated a tumor stain fed by the right angular artery and the posterior branch of the right middle meningeal artery. Total removal of the tumor was performed. Since histological examination disclosed meningothelial cells, whorl formation, polymorphism and necrotic tissue, she received radiation therapy (total 50Gy) under the diagnosis of anaplastic meningioma. On November 10, 1988, she suddenly developed headache, nausea, motor weakness and homonymous hemianopia on the left side. CT scan revealed intracerebral hemorrhage (ICH) near the region where the meningioma used to be. Magnetic resonance image (MRI) demonstrated a high intensity mass at T1-weighted image and mixed intensity mass at T2-weighted image. Furthermore, there were multiple low intensity spotty lesions at the cerebral and cerebellar hemisphere in T1 and T2-weighted image. A few parts of these lesions showed central high intensity cores and perifocal low intensity areas, which were called ring formations or reticulated cores with black rims. The multiple lesions could not be detected by CT scan. ICH was evacuated. Histological examination revealed no specific pathology except necrotic tissue around the hematoma wall. Diagnosis of radiation necrosis was made. On October 25, 1992 she suddenly complained of left hemihypesthesia. CT scan demonstrated two high density spotty areas at the left caudate head and right thalamus. MRI showed these two lesions as reticulated cores with black rims.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[A case of isolated oculomotor nerve palsy due to cavernous dural arteriovenous malformation (AVM)].

A 44-year-old man developed left-sided blepharoptosis and diplopia. Clinical examination showed left-sided blepharoptosis, a 2.5 mm dilated but reactive left pupil and an impaired left-eye adduction. There was no proptosis, bruit or conjunctival injection. Computed tomographic scan (CT) and magnetic resonance image (MRI) of the orbits, cavernous sinus region and brainstem were normal. Carotid angiography demonstrated a dural arteriovenous malformation of the left cavernous sinus supplied by the meningohypophyseal artery of the internal carotid artery and the middle meningeal artery of the extrenal carotid artery, with drainage into the inferior petrosal sinus. Magnetic resonance angiography (MRA; 3D-time of flight method) showed a slight vascular blush at the cavernous sinus region, but not enough to yield a diagnosis. The oculomotor nerve palsy resolved over the following 7 months.

Adult↗
PubMed1994

Variable loading cholangiomanometry and clinical applications.

We have designed a variable loading cholangiomanometric method, which permits a precise and objective evaluation of distal bile duct function. Normal resistance (R) values (1-7 units) and residual pressure (P) values (50-150 mm H2O) have been defined by this method. We have performed this procedure on 138 patients with cholelithiasis, and have found that 13 patients with cholecystolithiasis and 14 patients with choledocholithiasis have elevated R and P values in the distal bile duct. These patients also had morphological abnormalities in the distal bile duct. There was a high percentage of patients with abnormal pressure/flow curves at high flow rates among patients with morphologically dilated bile ducts. Division of pressure/flow curve patterns at low flow rates into three types made it possible to differentiate between functional and structural abnormalities. Patients in whom the residual P values were high and morphological defects of the distal bile duct. The possible application of these measurements in determining the need for additional surgery on the inferior bile duct, particularly papilloplasty, is discussed.

Bile Ducts↗
PubMed1994

[Tangier disease].

Tangier disease, a familial HDL-deficiency syndrome, was first reported by Fredrickson et al. in 1961. Since then, a great deal research on the mechanism of HDL-deficiency in this disease has been done from the prospective of lipoprotein compositions, in vivo HDL kinetics, cell and receptor interactions and genomic DNA analysis. These studies have found a relatively increased fractional catabolic rate of apo HDL with essentially no change in the synthesis of apo HDL. As yet, no structural defect has been found in the apo A-I gene. However, there have been reports of irregular lipid metabolism and of disorders in the Golgi apparatus and lysosome processing. Interestingly, the frequency of coronary heart disease is low in patients with Tangier disease. In this report, we describe the clinical and biochemical characteristics of Tangier disease and suggest some possible mechanisms for preventing coronary heart disease.

Apolipoproteins↗
PubMed1994

[Nuclear magnetic resonance relaxation times for human lung cancer and lung tissues].

We investigated the nuclear magnetic resonance (NMR) relaxation times, T1 and T2, for lung cancer tissue, and other samples of lung tissue obtained from surgical specimens. The samples were nine squamous cell carcinoma, five necrotic squamous cell carcinoma, 15 adenocarcinoma, two benign mesothelioma, and 13 fibrotic lungs. The relaxation times were measured with a 90 MHz NMR spectrometer and the results were correlated with histological changes. The values of T1 and T2 for squamous cell carcinoma and mesothelioma were significantly longer than those of adenocarcinoma and fibrotic lung tissue. There were no significant differences in values of T1 and T2 between adenocarcinoma and lung tissue. The values of T1 and T2 for benign mesothelioma were similar to those of squamous cell carcinoma, which suggested that increases in T1 and T2 are not specific to malignant tissues.

Adenocarcinoma↗
PubMed1994

Development of posterior fossa dural sinuses, emissary veins, and jugular bulb: morphological and radiologic study.

PURPOSE: To report the anatomic and radiologic development of the transverse, sigmoid, and occipital sinuses, the emissary veins, and the jugular bulb formation from the jugular sinus in humans before and after birth. METHODS: Roentgenograms of 33 injected brains showing the cranial venous system in human fetuses from 3 to 7 months of gestational age and cerebral angiograms of newborns and infants up to 6 years of age (23 clinical cases) were made and analyzed in detail. Special attention was focused on the inner diameters of the transverse and sigmoid sinuses and of the internal jugular veins, particularly at the sigmoid sinus-internal jugular vein junction. RESULTS: Marked increase in venous flow from the rapidly growing cerebral hemispheres leads to ballooning of the transverse sinuses in the absence of an increase in the inner diameters of the sigmoid and jugular sinuses. The ballooning also results in formation of the occipital sinus, marginal sinus around the foramen magnum, and emissary veins. The formation of the jugular bulbs from the jugular sinuses begins after birth when a shift from a fetal to a postnatal type of circulation (or from a lying-down position to an erect posture) takes place. CONCLUSION: The morphological changes of the posterior fossa dural sinuses, emissary veins, and jugular bulb are closely related to the development of the brain, shift to postnatal type of circulation, and postural hemodynamic changes.

Cerebral Angiography↗
PubMed1994

[Redo valve replacement for primary tissue failure of bioprosthetic heart valve].

We evaluated long-term results of valve replacement with bioprosthesis in 59 patients. Freedom from primary tissue failure and reoperation declined more than seven years after valve replacement. Seven patients underwent repeat operations because of primary tissue failure in our hospital. Their ages ranged from 32 to 54 years, two cases were male and five were female. At repeat operation, mechanical valve prosthesis were implanted to mitral position in all seven patients, tricuspid annuloplasty was added in five patients, and aortic valve replacement was added in one patients. The New York Heart Association (NYHA) functional classifications were grade II for 1 patient, III for 1, and IV for 5 preoperatively. Five patients had severe pulmonary hypertension preoperatively, and three of them were died after operation. The removed bioprostheses showed tears, perforations or calcifications of cusps and commissural detachments.

Adolescent↗
PubMed1994

Reversion of altered phenotype in primary cultured rat hepatocytes after intrahepatic and intrasplenic transplantation.

BACKGROUND: The phenotype of isolated rat hepatocytes changes during in vitro cultivation, but it is not clear whether this process turns back when the cells are returned to an in vivo milieu. Glutathione S-transferase placental form (GST-P), which is not expressed in hepatocytes in vivo, is induced within a few days of cultivation, whereas cytochrome P-450 constitutionally expressed in hepatocytes in vivo rapidly diminishes. We explored the dynamic nature of hepatocytic phenotypes using these two markers and intrahepatic and intrasplenic transplantation of cultured hepatocytes. EXPERIMENTAL DESIGN: Hepatocytes of F344 rats were isolated and cultured for 5 days to form spheroidal aggregates and then implanted into the livers and spleens of congenic analbuminemic rats. Expression of GST-P and P-450 was then examined immunocytochemically. In the intrahepatic case, the implanted hepatocytes could be distinguished from surrounding host hepatocytes by albumin immunostaining. RESULTS: The intrahepatically implanted hepatocytes turned GST-P-negative within 5 to 10 days, and re-expressed P-450 to a comparable level to that in surrounding host hepatocytes after 2 days. On the other hand, the hepatocytes implanted within spleens continued to express GST-P for 10 days, and started to express P-450 at extraordinarily high levels after 5 to 10 days. CONCLUSIONS: The phenotype of hepatocytes under in vivo and in vitro conditions has proven to be changeable from one to another.

Animals↗
PubMed1994

[Measurement of serum neuron-specific enolase levels after subarachnoid hemorrhage and intracerebral hemorrhage].

Neuron-specific enolase (NSE) is an enzyme involved in glycolysis and has a gamma-subunit. It is localized in neurons and axonal processes, and escapes into the blood and cerebrospinal fluid at the time of neural injury. In this study, the serum NSE levels in cases of subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (HIH) were measured. The subjects were 20 patients with subarachnoid hemorrhage (mean age; 53.4 +/- 14.5, 12 men and 8 women) and 20 with hypertensive intracerebral hemorrhage (mean age; 57.9 +/- 13.6, 11 men and 9 women). Although the serum NSE levels of all of these patients were measured on admission, measurement in patients with SAH were serially measured for an additional three weeks. There was no correlation between the serum NSE levels on admission in patients with SAH and consciousness level or clinical grade on admission, or prognosis. However, in Fisher's CT group 3 or 4, patients showed significantly higher levels of NSE than patients in group 2. Seven patients in whom vasospasm was observed by cerebral angiography during the course of treatment demonstrated elevated serum NSE levels from the 5th to the 15th days. In cases of HIH, there was also no correlation between the serum NSE levels from admission and consciousness level on admission or prognosis. However, the relationship between the size of the hematoma and serum NSE level on admission was significantly higher in patients in whom the maximum diameter was 5cm or more in comparison to those in whom the maximum diameter was less than 5cm.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1994

[Partial nuclear oculomotor nerve palsy, MLF syndrome, hallucinose pédonculaire due to midbrain infarction--a case report].

The authors report on a 62-year-old woman who suffered from partial nuclear oculomotor nerve palsy and the medial longitudinal fasciculus (MLF) syndrome caused by midbrain infarction. The lesion was confirmed to be in the mesencephalic tegmentum by axial sections acquired by magnetic resonance imaging (MRI). The lesion was located in the caudal region of the mesencephalic tegmentum by the sagittal MRI sections, and showed low signal intensity in T1-weighted images and high signal intensity in T2-weighted images. The patient exhibited bilateral ptosis due to the disturbance of caudal central nucleus and the supra-oculomotor area on both sides innervating the levator muscles of the upper eyelid. She also showed bilateral limitation of ocular adduction and supraduction; mild infraduction of the left eyeball; left monocular nystagmus; and disturbance of convergence, indicating partial involvement of the lateral somatic cell column innervating the muscles of the eyeball, the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the MLF. Furthermore, transient visual hallucinations similar to hallucinose pédonculaire were confirmed. We are not aware of any reports describing simultaneous occurrence of bilateral ptosis, MLF syndrome, and transient visual hallucinations similar to hallucinose pédonculaire in the same patient.

Cerebral Infarction↗