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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

At least 397 records · Page 22Linked to original sources
PubMed1996

Usefulness of thallium-201 single photon emission computed tomography to quantify the malignancy grade of brain tumors.

Preoperative thallium-201 (201Tl) single photon emission computed tomography (SPECT) was used to evaluate the histological malignancy in 24 patients with brain tumors. A corrected L/E ratio was calculated based on the ratio of thallium uptake in the tumor on early images versus the tumor in the delayed images (L/E ratio) corrected for thallium uptake in the contralateral cerebral hemisphere. The corrected L/E ratio in benign brain tumors was 0.79 +/- 0.23, significantly different to 1.32 +/- 0.25 in high grade astrocytomas (p < 0.01) and 1.19 +/- 0.05 in metastatic brain tumors (p < 0.01), respectively. The corrected L/E ratio in low grade astrocytomas was 0.64 +/- 0.32, significantly lower than that in high grade astrocytomas (p < 0.01) and metastatic brain tumors (p < 0.05). There was one false positive result among 24 patients using a threshold of 1.0 to separate malignant and benign tumors. 201Tl SPECT using the corrected L/E ratio is effective for determining the malignant viability of tumors.

Adult↗
PubMed1996

[A case of systemic sclerosis associated with interstitial pneumonia with various autoantibodies: improvement by intravenous cyclophosphamide therapy].

A 41-year-old woman was admitted to Tokyo Women's Medical College Aoyama Hospital in January 1994. She presented cough and dyspnea in September 1991. The diagnosis of interstitial pneumonia was made based on TBLB. Interstitial pneumonia was responsive to initial prednisolone of 40 mg daily. When dose of prednisolone was reduced to 15 mg daily, she complained of cough and dyspnea again. She was referred to Institute of Rheumatology, Tokyo Women's Maedical College in November 1993. She was diagnosed as systemic sclerosis associated with interstitial pneumonia based on proximal scleroderma and digital pitting scar. Double immunodiffusion and immunoprecipitation assay revealed the presence of anti-Ki, anti-Wa, and anti-RNA polymerases antibodies in the serum. On admission in March 1994, she was treated with intravenous cyclophosphamide therapy at 500 mg/day once a mouth. After the third infusion, respiratory symptoms, pulmonary function test values, findings of chest X-ray and CT scan were improved without adverse drug effects. Intravenous cyclophosphamide therapy seems to be useful in this case. The efficacy of Intravenous cyclophosphamide therapy in the treatment of the interstitial pneumonia associated with systemic sclerosis was discussed.

Adult↗
PubMed1996

Nonsurgical management of patients with blunt splenic injury: efficacy of transcatheter arterial embolization.

OBJECTIVE: We evaluated the efficacy of nonsurgical management of patients with blunt splenic injury using detailed angiographic examinations and transcatheter arterial embolization. SUBJECTS AND METHODS: We prospectively studied 228 patients who had blunt abdominal injury and for whom CT was performed. When splenic injury was revealed by CT, angiography was performed in all patients except those requiring emergency surgery. Transcatheter arterial embolization was performed when patients had the following angiographic criteria: (1) extravasation of contrast material extending beyond or within the splenic parenchyma, (2) arterial disruption or major arteriovenous fistula, or (3) both. Splenic function was subsequently estimated by 99mTc-sulfur colloid scintigraphy and repeat angiography. RESULTS: Of 228 patients with blunt trauma, 31 patients had CT evidence of splenic injury. In three of these 31 patients, emergency laparotomy was performed before angiography because of an associated injury or unstable circulatory status. In 13 of the 28 remaining patients, transcatheter arterial embolization was not required as these patients did not meet the necessary criteria. They were treated with bed rest. Transcatheter arterial embolization was performed in the remaining 15 patients and was completely successful in 13. Because one of these 13 patients died of a brain contusion, follow-up angiography and scintigraphy were performed in the remaining 12 patients and showed preservation of splenic function. Nonsurgical treatment of splenic injury with angiography was successful in 93% of patients. CONCLUSION: Our success rate for nonsurgical management of patients with blunt splenic injury should encourage more extensive evaluation and use of angiography for splenic injury and the subsequent management of splenic injury without surgery.

Adolescent↗
PubMed1996

Hemostasis with endoscopic hemoclipping for severe gastrointestinal bleeding in critically ill patients.

OBJECTIVES: The fact that endoscopic hemostasis is difficult to achieve and that the rebleeding rate is high in critically ill patients with gastrointestinal bleeding has often been reported. The purpose of this study was to examine the efficacy of endoscopic hemoclipping for gastrointestinal bleeding from ulcers and gastrointestinal lesions associated with critical illnesses. METHODS: Critically ill patients who were treated in a university hospital were studied prospectively. For patients with predefined clinically significant gastrointestinal bleeding, an established protocol of endoscopic hemoclipping (including indications and procedures) was used. RESULTS: Ten of 885 patients were treated according to this protocol. All suffered circulatory collapse, and respiratory management required intubation. The initial rate of hemostasis was 100%, and no rebleeding was observed. The APACHE III scores at 24 h after hemostasis were reduced, relative to the time of bleeding (p < 0.01). CONCLUSION: Endoscopic hemoclipping is useful in achieving hemostasis in critically ill patients with severe gastrointestinal bleeding.

APACHE↗
PubMed1996

[Stimulus effect of submaximal trains of impulses on nerves].

Although the occurrence of rate-dependent conduction block upon exposure to supramaximal stimuli is a well-known phenomenon, changes in the stimulus effect of submaximal trains of impulses on nerves remain unknown. To investigate changes in the stimulus effect, we evaluated median nerve action potentials using various frequencies of impulse trains. The subjects were 12 healthy controls and 9 patients with diabetic polyneuropathy. A tungsten microelectrode was inserted into the median nerve trunk at the elbow. Weak stimuli that produced 10 microV compound nerve action potentials were repeated. Each value recorded is the average of 20 trials. Repetition of 1- to 5-Hz stimuli yielded the same average wave, but above 7-Hz, the stimuli produced a diminution in amplitude and slight prolongation of the latency of each peak. This was most prominent with 50-Hz or 100-Hz repeated stimuli. The potentials changed amplitude with a waxing and waning pattern, and gradually stabilized at a lower level. The averaged wave corresponded to the record of reduced stimuli at 0.6 mA, maximally. Paired stimuli at an interval of less than 5 msec were equivalent to a relative refractory period, whereas at an interval of 4-18 msec they were equivalent to a supernormal period, and at 12-90 msec, to a subnormal period. The 'jumping' (unexpected shortening of the latency of a potential in response to increased stimulus intensity) of a single nerve unit was provoked or released corresponding to these periods. No differences were found between healthy individuals and patients with diabetic polyneuropathy. As a consequence of electrogenic Na+/K+ pumping, a three-Na+ ion efflux occurred instead of a two-K+ ion influx. Thus, repeated high-frequency impulses induced membrane hyperpolarization that reduced the stimulus effect on nerves. With trains of impulses at a frequency of 100-Hz, which corresponds to a stimulus every 10 msec, the second response was greater than the first, reflecting the supernormal period, but impulse trains provoked hyperpolarization, as mentioned above, and reduced the amplitude of nerve action potentials. The results of this study show that the stimulus effect on nerves decreased at submaximal stimuli greater than 7-Hz, which reduced the amplitude of compound nerve action potentials. Therefore, averaging should be done at a stimulus frequency below 6-Hz.

Action Potentials↗
PubMed1996

[A 65-year-old man with Parkinsonism, gaze palsy, and dementia].

We report a 65-year-old man with parkinsonism, supranuclear gaze palsy, and dementia. The patient was well until 58 years of the age (1984) when he noted an onset of tremor in his right hand. He visited our neurology service two years after the onset; neurologic examination at that time revealed moderate restriction in down ward gaze, horizontal gaze nystagmus in left and right gaze, stooped posture with loss of arm swing when he walked, slight rigidity in the neck and the right upper and lower extremities, and resting tremor in his right hand and foot; mentation was intact. He was treated with 600 mg of levodopa with carbidopa; his tremor partially improved. He received left Vim thalamotomy on March 14 of 1987. His tremor disappeared after the thalamotomy. Post-operative course was complicated by transient clouding of consciousness due to subdural hematoma which developed after the surgery. Six months after the surgery, he noted increase in the unsteadiness of gait; he also experienced urinary incontinence once in a while, and he became mentally dull. In November of 1988, he had episodes of stiffening of his body. Although his spontaneous speech was very much reduced, he repeatedly hummed a same tune; no one could make him stop humming. In June of 1989, he was totally unable to move his eyes in the vertical direction. He was hospitalized to another hospital in May of 1990 where he died six month after admission because of pneumonia. The clinical course of this patient was characterized by the onset with parkinsonian resting tremor, and supranuclear gaze palsy and dementia in the later course. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had an overlap syndrome of progressive supranuclear palsy (PSP) and diffuse Lewy body disease. Majority of the participants thought that the patient had progressive supranuclear palsy, but many of them had an impression that parkinsonian tremor responding to levodopa as the initial symptom for PSP is rather unusual. Postmortem examination revealed severe loss of neurons in the substantia nigra, the globus pallidus, and the subthalamic nucleus with reactive gliosis; formy spheroids were seen in the substantia nigra, however, no Lewy bodies or neurofibrillary tangles were observed. Moderate neuronal loss was also seen in the dentate nucleus of the cerebellum. In addition, the precentral gyrus showed moderate neuronal loss, astrocytosis, and spongy change in the second layer; ballooned neurons were seen in the third and the fifth layers. Histologic characteristics were consistent with the pathologic diagnosis of corticobasal degeneration.

Aged↗
PubMed1996

[Subarachnoid administration of lidocaine reduces delayed neuronal damage due to forebrain ischemia in rats].

We examined the effect of subarachnoid administration of lidocaine on delayed neuronal damage due to forebrain ischemia in rats. Sixteen rats were divided at random into two groups: lidocaine group rats (n = 8) and control group rats (n = 8) were subarachnoidally administrated lidocaine 5mg.kg-1 and normal saline, respectively, prior to ischemia. Forebrain ischemia was induced by bilateral carotid artery occlusion combined with systemic hypotension for 10 min. Cerebral perfusion-fixation was performed 7 days after ischemia, subsequent to which the brains were sectioned coronally and stained with celestine blue/acid fuchsin. In the neocortex and the hippocampal CA4 region, the lidocaine group showed less ischemic neuronal injuries than the control group. However, in the hippocampal CA1/CA3 regions and the caudoputamen, neuronal injuries in the lidocaine group were not significantly different from those in the control group. We conclude that the pre-ischemic subarachnoid administration of lidocaine reduces the delayed neuronal damage in neocortex and hippocampal CA4 region in the rat with forebrain ischemia.

Anesthetics, Local↗
PubMed1996

[A case of alpha-fetoprotein producing mediastinal germ cell tumor treated with preoperative chemotherapy].

A 20-year-old male was treated with 3 courses of cisplatin combined chemotherapy, with a clinical diagnosis of mediastinal germ cell tumor. Although alpha-fetoprotein (AFP), which alone had been high (893 ng/ml on admission) among tumor markers examined, normalized after chemotherapy, the size of the tumor remained unchanged. The patient underwent total resection of the tumor and has been followed with no evidence of recurrence for 18 months. Pathological examination suggested that the tumor was an immature teratoma with extensive proliferation of fibrous element. Neither other elements of germ cell tumor nor AFP producing cells were found. Preoperative chemotherapy is usually effective in treatment of germ cell tumors. However, it is important to recall that measurements of tumor volume occasionally do not provide information on the tumor's response.

Adult↗
PubMed1996

[Limited operation and simple lobectomy for primary lung cancer in poor risk patients].

During the years 1990 to 1994, 54 poor risk patients were performed relative noncurative operation for primary lung cancer, such as limited operation or lobectomy without mediastinal lymphnodal dissection. The indication for lesser resection were mainly cardiopulmonary diseases and the elderly over 75 years old. 3 were bilobectomies, 32 were lobectomies, 1 was lobectomy and segmentectomy, 10 were segmentectomies, 8 were wedge resections. The number of cases with stage I were 41 (75.9%). Postoperative complications occurred in 13 patients (24.1%). The overall 5-year survival rate was 63.5%. The 5-year survial rate of p 0 approximately p 1, pN 0 cases was 73.9%. Relative noncurative cases undergoing lesser resection showed relatively good result compared to standard lobectomy. It was considered that lesser resection for such poor risk patients with stage I can be a beneficial therapeutic modality.

Adenocarcinoma↗
PubMed1996

[A 63 year-old man with progressive gait disturbance and dysarthria].

We report a 63-year-old man with progressive gait disturbance and dysarthria. The patient was apparently well until the age of 62 (February, 1990) when he noted unsteadiness of gait. Two months later, dysarthria appeared. He was admitted to Juntendo Izunagaoka Hospital on April 23, 1990. Neurologic examination revealed a mentally sound man with normal higher cerebral functions. Cranial nerves were unremarkable except for scanning speech. His gait was ataxic with positive Romberg sign. No motor weakness was noted, however, he had hypotonia and cerebellar ataxia. Deep tendon reflexes were retained and the plantar response was flexor. Pain, touch and vibration senses were diminished in the distal parts of the lower extremities. Laboratory examination revealed a 2.5 cm mass in the left lung field. Cranial MRI revealed a small T1-low and T2-high signal intensity lesion in the left temporal lobe. Abdominal CT scan revealed multiple low density lesions in the liver. His subsequent course was complicated by progressive deterioration in his gait and loss of deep tendon reflexes. He expired on November 24, 1990. The patient was discussed in the neurological CPC and the chief discussant arrived at the conclusion that the patient had anti-Hu associated paraneoplastic encephalomyelitis and sensory neuropathy. Some other participants thought that the patient had carcinomatous cerebellar degeneration. Postmortem examination revealed a 4x4 cm mass lesion involving the left S4-S5 segments. Histologic examination of the tumor was small cell carcinoma. Many metastatic foci were found in the liver. The cerebral hemispheres were unremarkable except for a small wedge-shaped tissue defect in the left temporal lobe which appeared to have been caused by old head trauma which the patient had received. The cerebellar vermis showed slight enlargement of cortical sulci, however, the cerebellar hemispheres appeared unremarkable. Upon histologic examination, marked loss of Purkinje cells was noted, particularly in the cerebellar anterior lobe. The dentate nucleus showed slight cell loss with increase in fat granule cells. The inferior olive was normal. The histologic characteristics were consistent with the pathologic diagnosis of carcinomatous cerebellar degeneration. No evidence of limbic encephalitis was seen. The peripheral nerve was not examined.

Carcinoma, Small Cell↗
PubMed1996

Changes in cortical CBF and vascular response after vascular reconstruction in patients with adult onset moyamoya disease.

Using 133Xe single photon emission tomography, we evaluated the cortical region cerebral blood flow (rCBF) and vascular response to acetazolamide loading before and after vascular reconstructive surgery in 9 hemispheres in 6 patients with adult-onset moyamoya disease. Before the operation, the resting rCBF was not markedly impaired except that several low rCBF regions were present in the frontal and temporal lobes, and after the operation, the number of regions showing normal rCBF was significantly increased. Regional vascular response was more diffusely impaired in the regions with both normal and low rCBF before the operation, the excessively high response observed in the parietal and occipital lobes was well normalized after the operation, while the low response to acetazolamide challenge in the frontal and temporal lobes was not adequately improved.

Acetazolamide↗
PubMed1996

Induction of apoptosis in an androgen-independent mouse cell line by transforming growth factor-beta 1.

Androgen-dependent tumors eventually progress to androgen-independent tumors after androgen withdrawal. Androgen-independent CS2 cells could grow in serum-free culture whether androgen is present in the medium or not. In the present study, the mechanism of cell death in CS2 cells was examined after transforming growth factor-beta 1 (TGF-beta 1) treatment. Based upon the temporal sequence of DNA fragmentation, morphologic changes and loss of cell viability, these cells underwent apoptosis with TGF-beta 1 treatment. During the apoptotic process induced by TGF-beta 1, mRNA expression of testosterone repressed prostatic message-2, glucose regulated 78 kDa protein, and calmodulin increased. Flow cytometric analysis showed that TGF-beta 1 treatment resulted in a block in the G0/G1 phase of the cell cycle. These results demonstrate that although androgen withdrawal could not induce apoptosis in androgen-independent CS2 cells, these cells retain the ability to undergo apoptosis induced by TGF-beta 1. This system should be a good model for investigating apoptosis of hormone-independent cancer.

Androgens↗
PubMed1995

Structural elucidation of two novel amphoteric glycosphingolipids from the earthworm, Pheretima hilgendorfi.

The novel amphoteric glycosphingolipids containing a choline phosphate were purified from whole tissues of the earthworm, Pheretima hilgendorfi. Their chemical structures were completely characterized as cholinephosphoryl-->6(Man alpha 1-4)Gal beta 1-6Gal beta 1-1Cer (cholinephosphorylmannosylneogalabiaosylceramide, named PGL3a) and cholinephosphoryl-->6Gal beta 1-6Gal beta 1-6Gal beta 1-1Cer (cholinephosphorylneogalatriaosylceramide, named PGL3b) by compositional sugar, fatty acid and sphingoid analyses, hydrogen fluoride degradation, partial acid hydrolysis, methylation analysis, exoglycosidase degradation, proton magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. The ceramide moieties of these lipids consisted of 22:0, 23:0 and 24:0 acids as major fatty acids, and branched octadeca- and nonadeca-4-sphingenines and octadeca-4-sphingenine as main sphingoids. Since the oligosaccharides and the ceramide moieties of PGL3a and PGL3b were identical with those of neutral glycosphingolipids found in this organism, the biosynthesis of the amphoteric glycolipids may occur by the addition of a choline phosphate residue to the corresponding neutral glycolipids, Man alpha 1-4Gal beta 1-6Gal beta 1-1Cer or Gal beta 1-6Gal beta 1-6Gal beta 1-1Cer.

Animals↗
PubMed1995

Role of basic fibroblast growth factor in the regulation of rat basilar artery tone in vivo.

Using the cranial window method, we investigated the effect of basic fibroblast growth factor (bFGF) on the diameter of the rat basilar artery in vivo. bFGF (5-200 ng/ml) caused significant vasodilation in a dose-dependent manner with the maximal effect (119% of baseline diameter) at 200 ng/ml. Vasodilation was not observed when the basilar artery was treated with heat-inactivated bFGF or bFGF preincubated with bFGF-neutralizing monoclonal antibody. Moreover, bFGF-induced vasodilation was suppressed significantly by coadministration of the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). In contrast, NG-nitro-D-arginine methyl ester (D-NAME), which is the isomer of L-NAME, exerted no influence on bFGF-induced vasodilation. These findings suggest that the dilatation by bFGF of the rat basilar artery is mediated by NO, and that bFGF plays an important role in the regulation not only of the anterior circulation as previously described but also of the posterior circulation in the brain.

Animals↗
PubMed1995

Intraventricular administration of nitric oxide synthase inhibitors prevents delayed neuronal death in gerbil hippocampal CA1 neurons.

We performed experiments to investigate the participation of nitric oxide (NO) in the delayed neuronal death (DND) of gerbil hippocampal CA1 neurons, following 5-min forebrain ischemia with pretreatment of stereotaxic intraventricular administration of several types of NO synthase inhibitors and biologically inactive control drugs. The number of surviving neurons in the control drug groups administered NG-monomethyl-D-arginine or NG-nitro-D-arginine methyl ester was comparable to that in the group administered artificial cerebro-spinal fluid, while the groups administered NOS inhibitors, such as NG-monomethyl-L-arginine or NG-nitro-L-arginine methyl ester, showed significant preservation of the neuronal densities compared with the control drug groups, to over 60% of the sham operation group value. Furthermore, intraventricular administration of N omega-nitro-L-arginine at various concentrations disclosed a dose-dependent protection against the DND. These results suggest that the generation of NO may act to promote the establishment of DND.

Animals↗
PubMed1995

Diversity of T cell receptor delta-chain cDNA in the thymus of a one-month-old pig.

Pig TCR delta-chain cDNA sequences were obtained from the anchored PCR products of the reverse-transcribed RNA from the thymus of a 1-mo-old germfree pig. Among 43 sequences analyzed, 4 different J delta sequences were found, and in the cDNA sequences of rearranged V-D-J junctional regions, three putative D delta sequences were assigned. Also, the V delta region sequences were grouped into five families. One family, V delta 1, consisted of a large number of members and the other families consisted of limited members as determined by cDNA sequences as well as genomic Southern blots. Using PCR, V delta 1 gene segments were also obtained from liver genomic DNA of the same individual pig. Thirty-one distinct sequences were found for the V delta 1 family including the sequences obtained from both the thymic RNA and the PCR product of liver DNA. All the V delta 1 genes were found to be associated with almost identical leader gene sequences. The amino acid sequences of the complimentarity-determining region 3 coded by the V-D-J joints gave long and variable lengths with a high content of tryptophan and charged amino acids. The length of the complimentarity-determining region 3 in the porcine TCR delta-chain supports the idea that TCR delta-chain is designed to see Ags directly similar to the Ig heavy chain. Data presented from this study shows that the porcine TCR delta-chain has extensive V region diversity as well as junctional diversity. The combination of these two creates a level of diversity that is the highest of any lymphocyte Ag receptor studied so far.

Amino Acid Sequence↗