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Biomedical subjects

N Yoshimura

Publications and source records attributed to N Yoshimura.

At least 325 records · Page 18Linked to original sources
PubMed1995

Critical re-examination of the distribution of aromatase-immunoreactive cells in the quail forebrain using antibodies raised against human placental aromatase and against the recombinant quail, mouse or human enzyme.

Mouse and quail aromatase cDNAs were isolated from libraries of mouse ovary and quail brain by using a human aromatase cDNA fragment (hA-24) as a probe. These three cDNAs were inserted into plasmid vectors and expressed in Escherichia coli. Antisera against these purified recombinant proteins were raised in rabbit and purified by ammonium sulfate fractionation and affinity chromatography. The three antibodies directed against recombinant human, mouse and quail proteins were used to visualize aromatase-immunoreactive cells in the quail brain. They were compared with the antibody raised against human placental aromatase used in previous experiments and with another antibody recently developed by similar methods. The signal obtained with all antibodies was completely abolished by preadsorption with the homologous recombinant antigens and the signal produced by the two antibodies raised against placental aromatase was similarly abolished by a preadsorption with recombinant quail aromatase. The antibodies raised against recombinant proteins identified the major groups of aromatase cells previously described in the quail brain. The antibodies directed against the mouse and quail antigen identified more positive cells and stained them more densely than the antibodies raised against human recombinant antigen or purified placental aromatase. The new cell groups identified by the antibody raised against quail recombinant aromatase were located in an area ventral to the fasciculus prosencephali lateralis, the nucleus accumbens, the paleostriatum ventrale, the nucleus taeniae, the area around the nucleus ovoidalis, the caudal tuber and the mesencephalic central gray. A critical re-examination of the distribution and nomenclature of the aromatase-positive cells is proposed based on these new findings.

Animals↗
PubMed1995

Pharmacologic intervention for ischemic brain edema after retrograde cerebral perfusion.

Retrograde cerebral perfusion has recently been the focus of interest as a simple new technique of brain protection during aortic arch operations. We undertook the experimental protocol of 120 minutes of retrograde cerebral perfusion followed by antegrade reperfusion. Eighteen mongrel dogs were used. Retrograde cerebral perfusion was maintained at a flow rate of 150 to 250 ml/min to keep the perfusion pressure from 15 to 25 mm Hg. Animals were divided into three groups as follows: in group I, no treatment was received during and after retrograde cerebral perfusion; in group II, mannitol (2 gm/kg) was administered before cardiopulmonary bypass was restarted; and in group III, antivasospastic substance (1,2-bis nicotinamido]-propane) was continuously injected during and after retrograde cerebral perfusion (1 mg/kg per minute). Cerebral blood flow decreased during retrograde cerebral perfusion in all three groups. Cerebrovascular resistance showed marked increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with the values in groups II and III (group I: 3.35 +/- 0.73 and 5.00 +/- 1.57 mm Hg/ml per 100 gm per minute; group II: 1.30 +/- 0.33 and 1.03 +/- 0.17 mm Hg/ml per 100 gm per minute; group III: 1.24 +/- 0.41 and 0.98 +/- 0.24 mm Hg/ml per 100 gm per minute). The oxygen extraction level was reduced by cooling, but it rose to a higher level as a result of significant desaturation of returned blood even in deep hypothermia during retrograde cerebral perfusion. Both cerebral metabolic rate of oxygen and cerebral metabolic rate of glucose remained at low levels during retrograde cerebral perfusion. Ratios of cerebral blood flow to cerebral metabolic rate of oxygen and cerebral blood flow to cerebral metabolic rate of glucose were markedly reduced during retrograde cerebral perfusion. Intracranial pressure showed significant increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with values in group II or group III (group I: 22.7 +/- 2.8 and 20.6 +/- 5.1 mm Hg; group II: 6.3 +/- 1.8 and 5.3 +/- 1.3 mm Hg; group III: 4.2 +/- 1.7 and 7.7 +/- 2.8 mm Hg). Water content of the brain tissue in group I (77.54% +/- 0.29%) was significantly higher than that in group II (74.71% +/- 0.76%) or group III (74.14% +/- 0.48%). These data suggest that the supply of oxygen or glucose by retrograde cerebral perfusion is not enough to maintain sufficient cerebral metabolism, which may cause brain edema during antegrade reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

Utility of duplex Doppler ultrasound in evaluating portal hypertension in children.

We measured the maximal velocity of the blood flow in the main portal trunk by duplex Doppler ultrasound in children suffering from a variety of liver diseases. The maximal velocity of the main portal vein in children with chronic active hepatitis and liver cirrhosis was decreased significantly as compared to those in control children (p < 0.01). The maximal velocity of the main portal trunk and K indocyanine green (ICG) had no significant correlation (r = 0.25, n = 27). The patient with the lowest portal velocity had esophageal and gastric varices with red color sign. We conclude that the measurement of the maximal velocity of the main portal trunk with duplex Doppler ultrasound is useful in evaluating portal hypertension in children.

Adolescent↗
PubMed1995

Longer local retention of adoptively transferred T-LAK cells correlates with lesser adhesion molecule expression than NK-LAK cells.

The local retention of adoptively transferred lymphokine (IL-2)-activated killer (LAK) cells was examined in 11 patients with head and neck carcinoma. Unseparated lymphocytes, T and natural killer (NK) cells isolated from patients were cultured with IL-2 for 7 days, labelled with 99mTc-HMPAO, and immediately injected back into the respective donors via the superficial temporal artery or locally into the tumour tissue. The injected LAK cells were periodically traced using a gamma camera, and the LAK cell retention rate was calculated from the radioactivity. One hour after the injection, about 70% of the locally infiltrated LAK cells remained in the tumour tissue, while about half of the LAK cells transferred via the regional artery were dislodged from the tissue. LAK cells induced from T cells (T-LAK) were retained in the tissue for a longer time than LAK cells induced from NK cells (NK-LAK). T-LAK were less chemotactic and less adherent to human umbilical vein endothelial cells (EC), and showed lesser migration through EC. Flow cytometric analysis revealed higher expression of CD11a, CD11b, CD18 and CD49d on NK-LAK compared with T-LAK. MoAbs against these adhesion molecules suppressed adhesion and migration of LAK cells. These results indicate that the rapid disappearance of NK-LAK from the tissue is associated with their greater chemotactic and adhesive as well as migratory activities depending on differing expression of adhesion molecules.

Adult↗
PubMed1995

Histochemical localization of copper in various organs of brindled mice after copper therapy.

Copper (Cu) distribution in various organs of brindled mice (BM), an animal model of Menkes disease, was studied histochemically and by atomic-absorption-spectrophotometry 7 months after Cu injections. The results were compared with those of untreated BM. In the treated BM brain, a diffuse reduction in Cu-related staining of neurons and astroglia was still evident, though it had improved to some extent. The reduction was noticeable in the thalamus, brain stem and cerebellum, although intensely stained capillaries were noted occasionally in the retrosplenial and mediobasal temporal areas, including the hippocampus. In the treated BM liver, near normalization of Cu distribution was observed. In the treated BM intestine, the main localization of Cu accumulation was in histiocytes/macrophages in the lamina propria, while in the untreated BM it was in the absorptive and secretory epithelial cells. In the treated BM kidney, there was no clear improvement in Cu distribution. These histochemical results were consistent with the data obtained by the spectrophotometric assay. Electron microscopic histochemistry of affected renal tubular epithelial cells revealed numerous silver grains, which represent Cu++ localization, distributed only within the cytoplasm outside organella and nucleus. This suggests impaired intracellular Cu transport from cytosol to organella, which in the kidney is refractory to the Cu therapy adopted.

Animals↗
PubMed1995

Overview of effects of electrical stimulation on osteogenesis and alveolar bone.

One endpoint of periodontal therapy is to regenerate structure lost to periodontal disease. Periodontal regeneration requires both formation of a new connective tissue attachment to the tooth and formation of alveolar bone. Several procedural advances may support regeneration of the attachment, however, regeneration of alveolar bone does not occur consistently. Therefore, factors which stimulate bone repair are areas for research in periodontal reconstructive therapy. Effects of cytokines or growth factors on bone repair are examples of such areas. Another one is electrical stimulation which naturally occurs in bone, and as such bone may be particularly susceptible to electrical therapy. This overview describes the potential of electrical stimulation for bone regeneration and applications in alveolar and periodontal research.

Alveolar Bone Loss↗
PubMed1995

Drug-dependent Ca2+ mobilization in organ-cultured rabbit ciliary processes.

This study was conducted to determine whether drug-dependent changes in cytosolic Ca2+ concentration take place in the ciliary nonpigment epithelial cells of rabbits under more physiological conditions. Iris-ciliary body from pigmented rabbits in organ-culture was loaded with a Ca(2+)-sensitive fluorescent dye, fura-2, and a video-imaging system with an image analyzer was employed. Using this method fluorescence from nonpigmented epithelial cells can be analyzed without interference from fluorescence from pigmented ciliary epithelial cells. Among the drugs studied, norepinephrine and carbachol induced Ca2+ transients in the nonpigmented epithelial cells of organ-cultured ciliary processes. Epinephrine, isoproterenol, dopamine, neuropeptide Y, and substance P at the concentration of 10(-6) to 10(-3) M failed to elicit a response. The cytosolic free Ca2+ concentration of the cells in the resting state, as determined by an in vitro calibration curve, was 166 nM. The peak free cytosolic Ca2+ concentration induced by norepinephrine was about 263 nM, and that induced by carbachol was more than 1,000 nM. The carbachol-induced response was larger in magnitude and longer in duration than that induced by norepinephrine. Not uncommonly, the carbachol-induced response lasted more than 15 min. The response was diminished in both peak height and duration by chelation of extracellular Ca2+. Atropine abolished the response showing the response being mediated by a muscarinic receptor.

Adrenergic alpha-Agonists↗
PubMed1995

[A case of Ebstein's anomaly treated by tricuspid valve replacement].

A 8-year-old girl with Ebstein's anomaly was operated on because of progressive heart failure caused by severe tricuspid regurgitation. At the operation, the tricuspid leaflets were found to be destroyed, and the annulus was very enlarged. The enlarged true tricuspid annulus was constricted using the DeVega method, and the tricuspid valve was replaced on the true annulus using a porcine valve. To avoid injury to the auriculoventricular bundle, the suture line was shifted to the false annulus at the portion close to the course of His' bundle. Postoperative course was uneventful in satisfactory condition. The role of valve replacement in the treatment of Ebstein's anomaly of the tricuspid valve is not only to improve valve formation, but also to secure the function of the right ventricle. It is ideal to replace the tricuspid valve on the true annulus provided that the injury to the His' bundle is safely avoided.

Child↗
PubMed1995

Photocoagulated human retinal pigment epithelial cells produce an inhibitor of vascular endothelial cell proliferation.

PURPOSE: To determine if conditioned culture medium of photocoagulated human retinal pigment epithelial (RPE) cells contains inhibitors for the proliferation of bovine aortic endothelial cells (BAEC) and bovine retinal endothelial cells (BREC) and to characterize the nature of these inhibitory factors. METHODS: Retinal pigment epithelial cells grown to confluence were photocoagulated (0.1 second, 50 microns, 350 mW) in serum-free medium. After 48 hours, the conditioned medium (PC-CM) was removed, and the effects of non-acid-treated and transiently acid-treated samples were determined on [3H]-thymidine uptake by BAEC and BREC. PC-CM was also subjected to size exclusion high-performance liquid chromatography (HPLC). Fractions were analyzed for the effects on the growth of the bovine endothelial cells before and after transient acid treatment. RESULTS: The addition of non-acid-treated PC-CM (32% vol/vol) inhibited BREC [3H]-thymidine uptake to 18.5% of the control value. With HPLC, the inhibitory activity was recovered mainly in a fraction whose apparent molecular size was 25 kd. After transient acid treatment of the fractions, there also appeared a 100-kd inhibitor. Inhibitory effects were neutralized by pretreatment of the fractions with antiserum against transforming growth factor (TGF)-beta 2. CONCLUSIONS: Photocoagulated RPE cells secrete inhibitors of BAEC and BREC proliferation. Molecular size and immunologic properties of these inhibitors correspond to those of TGF-beta 2.

Animals↗
PubMed1995

[Comparison of blood pressures measured directly at the radial and dorsalis pedis arteries during epidural anesthesia].

Differences of blood pressures measured directly at the radial and dorsalis pedis arteries were compared in relation to the sites of the epidural puncture. Epidural catheters were inserted at C7-Th9 in the upper (U) group (n = 7), and at L1-4 in lower (L) group (n = 7). In the awake, unanesthetized state, the systolic, mean and diastolic radial-to-dorsal pressure differences (DR-D) were -21.9 +/- 11.0 mmHg (mean +/- SD), 0.9 +/- 1.1 mmHg and 2.1 +/- 2.1 mmHg respectively. Following epidural infusion of mepivacaine, the DR-D values shifted to the negative direction in the U group, and to the positive direction in the L group. Epidural anesthesia had little effect on the DR-D changes during general anesthesia; however, it affected significantly the mean pressure DR-D as well as the systolic pressure DR-D during the periods of preinduction and postemergence. The maximum change in systolic pressure DR-D values was from -19.4 to -36.3 mmHg in a patient of the U group and from -15.6 to 45.4 mmHg in a patient of the L group. The maximum change in mean pressure DR-D values was from 0.0 to -7.4 mmHg in the U group and from 2.1 to 18.3 mmHg in the L group. The DR-D values had significant negative correlations with the deep temperature (palm to sole) differences; the correlation coefficients were: systolic, r = -0.50; mean, r = -0.50; and diastolic, r = -0.41. These results demonstrated that epidural anesthesia changed the physiological central-to-peripheral pressure gradients, probably by influencing the regional peripheral vascular resistance.

Adult↗
PubMed1995

[A surgical case of aortic dissection Stanford type A caused by blunt chest trauma--a report of a successful case].

A case of successfully repaired traumatic aortic dissection was reported. A 66-year-old woman with a blunt chest trauma from the car accident was transferred to our hospital. The radiological examination revealed Stanford type A aortic dissection without aortic regurgitation. Because of disturbance of consciousness and respiratory failure due to the associated blunt lung injury, she was treated in the intensive care unit, and, after 1 month, a graft replacement of the ascending aorta by using deep hypothermia with retrograde cerebral perfusion was carried out. The postoperative course was uneventful. Blunt chest trauma is very rare to cause aortic dissection, and the operative indication should be determined with careful consideration of the associated organ injuries.

Aortic Dissection↗
PubMed1995

[High-resolution CT findings of Pneumocystis carinii pneumonia].

High resolution CT (HRCT) was performed on 7 patients with pneumocystis carinii pneumonia (PCP). Six cases were proven bacteriologically by bronchoalveolar lavage; one case was proven by autopsy. Three patients were re-scanned after specific treatment and symptomatic relief. All the CT scans were abnormal, usually showing bilateral diffuse ground-glass opacity, through which the pulmonary vessels remained visible. Chest X-ray, on the other hand, showed a normal pattern in one patient. Other changes such as air space consolidation (in 4 cases) and thickening of peripheral pulmona vessels (in 2 cases) were also seen. Air space consolidation was found in three cases with mixed infection (cytomegalovirus pneumonia in 2 cases, aspergillosis in one case). No patient showed significant mediastinal or hilar lymph node enlargement, pleural effusion or cystic pulmonary change. HRCT findings such as ground-glass opacity and air space consolidation were shown to disappear in some cases of PCP after specific treatment. HRCT is useful to evaluate the sequential pulmonary changes after the specific therapy.

Adult↗
PubMed1995

[Non-invasive monitoring of cerebral oxygenation by NIR spectrophotometry (clinical trial)].

A Shimazu OM-100A near infrared spectrophotometer was used to monitor the cerebral oxygenated hemoglobin (Oxy-Hb), deoxygenated hemoglobin (Deoxy-Hb) and total hemoglobin (Total-Hb) in 3 patients with a) massive hemorrhage, b) ruptured aneurysm in the abdominal aorta, or c) hypercapnia. The hematocrit value of the patient with massive hemorrhage decreased rapidly to 18 %; the Total-Hb and Oxy-Hb also decreased significantly. Red blood cell transfusion raised the Oxy-Hb level, indicating an improvement in cerebral oxygenation. In the patient with a ruptured aneurysm, changes in blood flow brought about by clamping or declamping of the abdominal aorta were immediately reflected by corresponding changes in Total-Hb and Oxy-Hb. Oxy-Hb increased significantly and correlated well with the PETCO2 value in the patient with hypercapnia. Thus, NIR spectrophotometry is a useful non-invasive tool which can monitor metabolic and hemodynamic changes in the brain in various pathological conditions.

Adult↗
PubMed1995

[A case of thymic carcinoma successfully controlled by combined chemotherapy and irradiation].

There is no well established therapeutic protocol for advanced thymic carcinoma, although chemotherapy and irradiation can apparently be used to control the malignancy. Here we report a case of advanced thymic carcinoma successfully controlled by combination of treatment with systemic chemotherapy and irradiation. A 79-year-old man was admitted to the Hiratsuka Kyosai Hospital with complaints of productive cough and dyspnea. Chest roentgenogram and computerized tomography on admission revealed a tumorous lesion in the anterior mediastinum and on accumulation of left pleural and pericardial effusion fluid. The tumor was diagnosed as a thymic squamous cell carcinoma, after percutaneous needle biopsy. Because of extension to the left pleura and cardiac sac, the tumor was considered to be unresectable and systemic chemotherapy (CDDP + VDS + MMC) was begun. After drainage of the pericardial effusion fluid, intrapericardial injection of MMC was also done. The anterior mediastinum was irradiated. The patient has been doing well, with regression of the thymic tumor for 48 months after irradiation. This case provides important information that can be used to establish an effective therapeutic regimen for advanced thymic carcinoma.

Aged↗
PubMed1995

[Effects of dopamine and dobutamine on vascular smooth muscles].

The effects of dopamine and dobutamine on mechanical responses of the mesenteric artery and ear artery of the rabbit were investigated. Dopamine elicited no contraction in the mesenteric artery, but inhibited contractions evoked by excess concentrations of K+ or norepinephrine. In contrast, in the ear artery, dopamine induced contractions in concentrations exceeding 0.7 microM. Dobutamine did not induce contractions either in the mesenteric artery or ear artery, but inhibited contractions evoked by excess concentrations of K+ or norepinephrine in both tissues. Moreover, dobutamine in concentrations over 10 nM inhibited contractions induced by dopamine in the ear artery. These results indicated that regional differences were apparent in the effects of dopamine on vascular tissues and that dobutamine possessed vasodilating effects. The inhibitory effects of dobutamine on contractions induced by dopamine in the rabbit ear artery suggested a possible clinical benefit of dobutamine for maintaining peripheral circulation during combined use of dopamine and dobutamine.

Animals↗
PubMed1995

[Response of individual abdominal muscles to nasal CPAP in supine and standing positions in humans].

The respiratory function of individual abdominal muscles in humans is not well known. Some workers have reported that abdominal muscles act as a single unit during breathing, whereas others have reported differential activation. In the present study, fine wire electrodes were inserted into the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and transversus abdominis (TA) muscles in six healthy awake subjects under direct vision provided by high-resolution ultrasonography. Electromyographic (EMG) signals were then recorded in the supine and standing positions during resting ventilation without nasal continuous positive airway pressure (nCPAP), then on nCPAP at 5, 10, 15, and 20 cmH2O. Peak values of integrated EMG during expiration were measured. For each abdominal muscle, the number of subjects showing expiratory EMG activity increased with increasing nCPAP or with a change in posture from supine to standing or both. The number of subjects showing expiratory abdominal muscle activity under any condition followed the order: RA < or = EO < or = IO < or = TA. Peak expiratory EMG activity increased significantly with increasing nCPAP in the standing position for EO (p < 0.05), and in both positions for IO and TA (both p < 0.01). These results suggest that: 1) both the standing position and nCPAP imposed an expiratory load, 2) TA and IO are most sensitive to expiratory loading, and are the primary expiratory muscles, and 3) RA is least sensitive to expiratory loading, and is a secondary expiratory muscle. We conclude that individual abdominal muscles respond differently to expiratory loading.

Abdominal Muscles↗