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Biomedical subjects

A Sakamoto

Publications and source records attributed to A Sakamoto.

At least 235 records · Page 13Linked to original sources

Free radical formation during splanchnic artery occlusion shock.

Free radical (FR) formation in the rat intestinal lumen was measured using the spin-trapping technique and electron paramagnetic resonance spectroscopy. Intestinal ischemia was produced by occluding the celiac and the superior mesenteric arteries for 30 min followed by reperfusion. The lumen was filled with a solution of PBN (N-tert-butyl-alpha-phenyl-nitrone) and the intestine was squeezed to enhance the interaction between the PBN solution and the intestinal mucosal cells. Free radicals were produced upon reperfusion, with peaks at 5 and 90 min. Post-ischemic treatment with superoxide dismutase (20 mg.kg(-1)) inhibited the increase of FR production during the second peak by 36%. In a single study in a group of leucocytopenic rats (WBC < 1500/mm(3)), the increase of FR production during the second peak was decreased by 80%. However, these treatments did not inhibit the FR production during the first peak in either group. In contrast, pretreatment with allopurinol (40 and 100 mg.kg(-1) injection at 24 and 3 hours before ischemia, respectively) inhibited the FR production during the first peak by 76%, but did not inhibit during the second peak. The changes in lipid peroxidation in the intestinal mucosa, specific gravity of the intestine and in the hematocrit were correlated to the FR production in the second peak. These results suggest that a major cause of tissue injury after reperfusion in the ischemic intestine may largely be produced by neutrophils.

Journal Article↗

Inhibition of lipid peroxidation by prostaglandin oligomeric derivatives.

The inhibition of lipid peroxidation by oligomeric derivatives synthesized from prostaglandin E1 (PGE1) and PGB2 was studied using two rat models. In an in vitro model, the brain was exposed to decapitation-ischemia, the cortex was removed and homogenized, and the formation of thiobarbituric acid reactive substances (TBAR) was measured after exposing the homogenate to in vitro reoxygenation either in the presence or absence of oligomers. It was found that these oligomers could inhibit lipid peroxidation, and that their activities were higher than that of superoxide dismutase (SOD). In an in vivo administration model, either the oligomer or the vehicle was injected i.p. 30 min before decapitation. The brain was exposed to decapitation-ischemia, the cortex was homogenized and exposed to 'in vitro' reoxygenation, after which TBAR value was determined. Ester-type compounds had a greater activity than free-acid type compounds in inhibiting lipid peroxidation. A possible mechanism of the protective effect of these oligomers in ischemia/reperfusion injury may be to scavenge oxygen free radicals.

Alprostadil↗

Predominant expansion of V gamma 9/V delta 2 T cells in a tularemia patient.

We describe a 58-year-old man with tularemia and expanding gamma delta T cells in his peripheral blood lymphocytes (PBL) (32.7% of total PBL). In the present work, we analyzed the T-cell receptor V gamma/V delta repertoire of these cells by making use of the polymerase chain reaction and flow cytometry and found that they were mostly CD4- CD8- CD3+ V gamma 9/V delta 2+. The sequence analysis of 16 cDNA clones encoding the V gamma 9-J region revealed that the V gamma 9-Jp combination was strikingly overrepresented but that the junctional (N) region was heterogeneous. This suggested that the gamma delta T cells in PBL from a patient with tularemia were polyclonally expanded.

Base Sequence↗

Lobenzarit disodium (CCA) inhibits in vitro immunoglobulin production via direct interaction with B lymphocytes.

The regulatory effects of lobenzarit disodium (CCA), a therapeutic agent for treating rheumatoid arthritis (RA), on polyclonal immunoglobulin production by human lymphocytes were investigated in vitro. CCA inhibited the production of immunoglobulin in all the classes examined at a clinically relevant concentration. Moreover, it inhibited the immunoglobulin production as well as lymphocyte proliferation even when purified B lymphocytes preactivated by Staphylococcus aureus COWAN I were cultured with recombinant lymphokines such as IL2 and IL6. These results suggest that CCA acts directly on B lymphocytes. The analysis at each of two different stages of B lymphocyte activation lineage, i.e., the primary activation stage and a stage of proliferation and differentiation to antibody secreting cells, has indicated that CCA inhibits the proliferation-differentiation stage of B lymphocytes. CCA does not inhibit B lymphocytes at the primary activation stage; actually, it augments them, resulting in the subsequent enhancement of immunoglobulin production.

Adult↗

A rare case of extramedullary plasmacytoma in the mediastinum.

A rare case of extramedullary plasmacytoma in the mediastinum is reported. An 80-year-old man was admitted for further examination of a mediastinal tumor. Chest computed tomography (CT) revealed a large mediastinal mass and right interlobar pleural effusion. Needle biopsy under CT guidance established a diagnosis of plasmacytoma. Immunohistochemical staining revealed that the tumor cells were producing monoclonal IgA kappa. Serum immunoelectrophoresis revealed an IgA kappa monoclonal component with a serum concentration of 5,040 mg/ml. The bone marrow aspiration was normal. Bone roentgenogram and bone scintigram showed osteoporosis but no neoplastic lesion.

Aged↗

[ESR study of free radical formation during ischemia-reperfusion injury in the rat brain and the protective effect of a new antioxidant].

By using the spin-trapping technique and electron spin resonance spectroscopy (ESR), we detected directly oxygen-derived free radicals in the brain exposed to ischemia and reperfusion. Forebrain ischemia was produced in the rat by bilateral occlusion of the common carotid arteries combined with hemorrhagic hypotension. The whole cerebral cortex was homogenized in the presence of the spin trap agent, N-tert-butyl-alpha-phenylnitrone, followed by a Folch extract. Spin-adducts were detected using ESR. As the index of tissue injury, the lipid peroxidation was estimated from both the amount of thiobarbituric acid reactive substance and the formation of conjugated diene. After 10 or 20 min of ischemia, reperfusion induced a burst of spin adduct formation which peaked at 5 min reperfusion time. The peak value increased with the ischemia time. The degree of lipid peroxidation, which was measured after 20 min of reperfusion, also increased with the ischemia time. When the oligomeric derivative was administered (9 mg . kg-1, i.p.) 30 min before ischemic insult, both spin adduct formation and lipid peroxidation were reduced. The results support the current view that free radicals produced upon reperfusion may be the direct cause of the subsequent lipid peroxidation.

Animals↗

[Selection of graft materials in case of emergency coronary bypass surgery following failed angioplasty].

The clinical characteristics of selection of graft materials were analysed for patients undergoing emergency coronary artery bypass surgery (CABG) following failed coronary angioplasty (PTCA). Ten emergency CABGs were performed from January 1983 to December 1991. Perioperative variables and follow-up were compared to 18 patients undergoing elective CABG after PTCA. The emergency group had shorter operative time (p less than 0.01) and shorter bypass time (p less than 0.05). Moreover the emergency group had decreased use of the internal thoracic artery (ITA) (40% vs 94.4%, p less than 0.01). There was no use of bilateral ITAs in the emergency group. There was not significant difference in hospital mortality and medium term follow-up between two groups. In conclusion, emergency CABG carries a significantly less use of ITA graft than elective CABG although ITAs are superior to SVGs about long term patency rate. So it is desirable that arterial graft should be used under an appropriate selection at emergency operation.

Aged↗

[A 14-year-old with pulmonary hamartomatous lymphangiomyomatosis associated with bilateral pneumothoraces].

A 14-year-old girl was admitted because of cough, chest pain and hemosputum. Chest roentgenogram on admission showed a pneumothorax and a cavitary lesion with niveau formation in the right lung and cystic lesions in the bilateral lung fields. After bed rest and intravenous administration of antibiotics for two weeks, the right lung inflated well and the niveau formation disappeared, and the patient was discharged. One week later, she was readmitted with sudden-onset severe dyspnea, caused by bilateral pneumothoraces. Emergency tube thoracostomy and wedge resection of the bullous lesion was performed. Macroscopically, multiple small cystic changes were seen on the surface of the right lung. Histological examination revealed nodular proliferations of smooth muscle cells in the interstitium and vessel walls in the lung, which contained slit-like lymphatic channels. The diagnosis of pulmonary lymphangiomyomatosis was made. In this case, we could not measure receptors for estrogen and progesterone. Recently, hormonal therapy and oophorectomy have been reported as being useful. Tamoxifen (Norvadex) was therefore initiated, and the patient has remained well with slight dyspnea on exertion. There has been no recurrence of pneumothorax. Lymphangiomyomatosis is a rare disease of unknown etiology which occurs exclusively in women, mostly in those of reproductive age. We report a 14-year-old female patient with lymphangiomyomatosis associated with repeated pneumothorax, who had been under treatment for epilepsy. We believe this case to be of importance because of the long discussed relation between pulmonary lymphangiomyomatosis and tuberous sclerosis.

Adolescent↗

[A case of pulmonary fibrosis in which inhibition of pulmonary vasoconstriction was detected using DSA pulmonary wedge angiography].

A 65-year-old man was admitted to our hospital complaining of productive cough and dyspnea on exertion. X-ray films and CT scan of the chest disclosed diffuse reticular shadows, especially in the bilateral lower lung fields. Blood gas analysis showed severe hypoxemia. Pulmonary function test disclosed severe restrictive pattern. From these findings, the patient was thought to have pulmonary fibrosis. Right heart catheterization showed pulmonary hypertension. To evaluate the pulmonary vascular bed, we performed DSA pulmonary wedge angiography. The pulmonary capillary phase stained homogeneously in normal subjects. However, in the present case, filling of the right pulmonary A9 was incomplete and capillary bed staining was decreased under room air condition. After breathing 5 L/min oxygen for 20 min., the A9 was filled well and capillary bed staining was increased. We consider that this change was induced by inhibition of hypoxic pulmonary vasoconstriction (HPV) by oxygen. DSA pulmonary wedge angiography was useful for visual evaluation of HPV.

Aged↗

[A case of pulmonary adenocarcinoma in a young man with multiple metastasis to the nasopharynx and paranasal sinuses].

A 36-year-old man who complained of bloody sputum showed a mass-like shadow in the right upper lung field on chest X-ray, which was diagnosed as adenocarcinoma by sputum cytology in August, 1990. Since his clinical stage was too advanced for curative operation, chemotherapy was started on October 1, 1990. On October 26, he brought up a polyp-like mass, and was found to have polypoid tumors on the bilateral tonsils and nasopharynx, which were biopsied and diagnosed as poorly-differentiated adenocarcinoma. On November 21, CT of the face showed soft tissue density tumors in the bilateral paranasal sinuses. According to the clinical course, all tumors were thought to be metastatic lesions. Since he had suffered from epistaxis and nasal obstruction due to the enlargement of metastatic tumors, nebulization chemotherapy and palliative resection were performed. In February 1991, he developed severe headache due to brain metastasis. Despite irradiation therapy, he died from cerebral intra-tumorous hemorrhage on February 22. We reported a rare incurable case of lung cancer with metastasis to the nasopharynx and paranasal sinuses.

Adenocarcinoma↗

Abnormalities of the autonomic nervous system of the duodenum in streptozotocin-induced diabetic rats.

The changes in sensitivity of the rat duodenum to ATP were examined in preparations from control rats and from rats with streptozotocin (STZ)-induced diabetes. ATP was able to relax the duodenum of control animals in a concentration-dependent manner and this relaxation was significantly increased in STZ-diabetic rats. In preparations from diabetic rats, relaxation responses to ATP were greater than those of age-matched control groups. These results suggest that functional changes or degeneration of non-adrenergic, non-cholinergic nerves in the myenteric plexus may occur in STZ-diabetic rats, and that these alterations may result in the increased sensitivity of the relaxation of the duodenum to ATP.

Adenosine Triphosphate↗

Cloning and functional expression of human cDNA for the ETB endothelin receptor.

We report the cloning of human cDNA encoding an ETB (non-isopeptide-selective) subtype of the endothelin receptor. The predicted amino acid sequence of the human ETB endothelin receptor was 87.8% and 62.9% identical with the previously cloned rat ETB and ETA receptors, respectively. COS cells transiently transfected with the cloned cDNA expressed specific, high-affinity binding sites for endothelin isopeptides and responded to the peptides with a transient increase of [Ca2+]i; endothelin-1 and endothelin-3 exhibited approximately equal potencies both in displacing 125I-labeled endothelin-1 binding and in eliciting [Ca2+]i transients. The ETB receptor mRNAs were expressed in various human tissues and also in the intact porcine aortic intimal cells ex vivo.

Amino Acid Sequence↗

Relationship between free radical production and lipid peroxidation during ischemia-reperfusion injury in the rat brain.

Forebrain ischemia was produced in the rat by bilateral occlusion of the common carotid arteries combined with hemorrhagic hypotension (30 mmHg). The whole cerebral cortex was homogenized in the presence of the spin trap agent N-tert-butyl-alpha-phenyl-nitrone, followed by a Folch extract. Spin-adducts were detected using electron spin resonance spectroscopy. The lipid peroxidation was estimated from both the amount of thiobarbituric acid reactive substance and the formation of conjugated diene. After 10 or 20 min of ischemia, reperfusion was initiated which induced an abrupt burst of free radical formation. The formation peaked at 5 min, and the peak value increased with the ischemia time. The degree of lipid peroxidation, which was measured after 20 min of reperfusion, also increased with the ischemia time. The results suggest that the lipid peroxidation may be the direct consequence of the action of free radicals formed during ischemia and reperfusion periods.

Animals↗

Subserosal adenomyosis: a possible variant of pelvic endometriosis.

A total of 128 patients with adenomyosis were examined clinically and histologically to investigate the pathogenesis of subserosal adenomyosis. In this study 15 (11.7%) cases were classified as subserosal adenomyosis on the basis of localization of heterotopic endometrial tissues that consisted of glands and stroma. These were subclinical and incidental. The uterus was not enlarged in this type of adenomyosis. Distribution of the ectopic tissues and the patients' mean age at the time of the hysterectomy suggest that subserosal adenomyosis may develop as a variant of pelvic endometriosis.

Adult↗

Protective effect of a new anti-oxidant on the rat brain exposed to ischemia-reperfusion injury: inhibition of free radical formation and lipid peroxidation.

A new oligomeric derivative was synthesized from prostaglandin B2 and ascorbic acid, and its effect on rat brain ischemia-reperfusion injury was studied. Brain ischemia was produced in the rat by the combination of bilateral common carotid artery occlusion and hemorrhagic hypotension (30 mmHg, 20 min). The cerebral cortex was homogenized in the presence of the spin trap agent, N-tert-butyl-alpha-phenyl-nitrone (PBN). Spin-adducts were detected using an electron spin resonance spectrometer (EPR). Lipid peroxidation was estimated from the amounts of both thiobarbituric acid reactive substances (TBAR) and conjugated diene. In control experiments, reperfusion induced a burst of free radical formation which peaked at 5 min reperfusion time (238 +/- 41%). Lipid peroxidation increased significantly after 20 min of reperfusion (TBAR, 161 +/- 50%; conjugated diene, 160 +/- 29%). When the oligomeric derivative was administered (9 mg/kg i.p. 30 min before ischemic insult), it significantly reduced both spin adduct formation (103 +/- 13%) and lipid peroxidation (TBAR, 109 +/- 14%; conjugated diene, 97 +/- 33%).

Animals↗

Intracranial recordings of movement-related potentials to voluntary saccades.

Movement-related potentials evoked by voluntary and self-initiated horizontal saccades were recorded from subdural electrodes placed over the lateral (premotor and motor cortex) and the mesial (supplementary motor area) surfaces of the frontal lobe, in four patients with intractable focal seizures. An extremely localized bereitschaftspotential showing approximately the same latencies and amplitudes was simultaneously recorded from the frontal eye field and supplementary motor area (SMA). Our data suggest that both regions are equally active prior to saccades and do not support the view that the SMA acts as a supramotor cortex, being activated during the planning of the movement and the primary motor cortex only later on, close to the execution of the movement. In addition, we never observed the spike potential in our intracranial recordings, thus supporting the hypothesis of its extracerebral origin.

Adult↗

Adult T-cell leukemia/lymphoma with gastric lesions. Report of three cases.

We describe three cases of adult T-cell leukemia/lymphoma (ATL) with malignant cell infiltration into the stomach. Case 1, a 63-year-old man, had a large ulcerative lesion on the lesser curvature of the upper stomach. Case 2, a 44-year-old man, had an irregular depressed lesion simulating a IIc-type early gastric cancer on the posterior wall of the mid portion of the stomach. Case 3, a 58-year-old man, had multiple irregular depressed lesions on the lesser curvature of the lower part of the stomach. In all cases, histologic examinations of the biopsy specimens confirmed ATL-cell infiltration into the stomach. In cases 1 and 2, repeated roentgenographic and endoscopic examinations revealed the characteristic changes of the gastric lesions over the course of time.

Adult↗