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Biomedical subjects

H Kitamura

Publications and source records attributed to H Kitamura.

At least 325 records · Page 18Linked to original sources
PubMed1994

Changes in morphology of elastin fibers during development of the tunica intima of monkey aorta.

The normal development of elastin fibers in the thoracic aorta was studied in fetal, young, and adult monkeys. Tissue was examined by scanning electron microscopy (SEM) after NaOH treatment and by transmission electron microscopy (TEM). The NaOH treatment of fixed tissues effectively removed collagen fibers and enabled three-dimensional visualization of the elastin fibers. In intact fetal aortae, the internal elastic lamina (IEL) was situated immediately beneath the endothelium. This IEL consisted of superficial, longitudinally arranged bundles of elastin fibrils and an underlying solid sheet containing round fenestrations. In neonates, diffuse intimal thickening was observed. In the young and young-adult monkeys, the aortae exhibited intimal thickening with slender but split IEL. One of the most important findings of this study was that elastin fibers in the intimal thickening, as well as smooth muscle cells, ran in a longitudinal fashion. This was in contrast with the elastic laminae of the media which were mainly oriented circumferentially. Subendothelial elastin fibers in this intimal thickening combined with longitudinally arranged microfibrils which formed close associations with endothelial stress fibers. In some adult monkey aortae with well-developed intimal thickening, a complex meshwork of slender elastin fibers was also found beneath the endothelium. The development of the intimal elastin fibers is discussed in relation to hemodynamic forces.

Actin Cytoskeleton↗
PubMed1994

Thymus carcinoid producing parathyroid hormone (PTH)-related protein: report of a case.

We report herein the rare case of a thymus carcinoid producing parathyroid hormone (PTH)-related protein (PTHrP) found in a 43-year-old Japanese man who presented with a 19-month history of dyspnea. The diagnosis of a carcinoid was established by light microscopic, electron microscopic, and immunohistochemical examinations. The tumor was considered to be thymic in origin because of its anatomic location, the presence of feeders to the tumor (derived from the internal thoracic arteries), and the fact that no other tumors from which it could have originated were found. After an excisional biopsy, which revealed PTH-related immunoreactivity in the tumor cells, 60 Gy of irradiation was delivered, resulting in a 48% reduction in the size of the tumor. Flow cytometry showed a diploid DNA pattern, with 94% of the cells in the G1 phase, 4% in the S phase, 2% in the G2 + M phase, and a G2 + M/G1 ratio of 1.95. The primary cell culture showed some cells adopted in a cord-like pattern. To our knowledge, this is the first report of a carcinoid tumor in which positive staining for PTHrP by immunohistochemical methods was demonstrated.

Adult↗
PubMed1994

Experimental assessment of spectrum analysis of ultrasonic echoes as a method for estimating scatterer properties.

In vitro experiments using weak scatterers ranging in size from mean longest diameter of 26.9 to 83.0 microns were performed to test the validity of theoretical predictions for scatterer size and concentration derived from normalized power spectrum parameters of ultrasonic backscatterer echoes. Scatterers consisting of cell clusters were suspended in collagen gel and scanned by a 10 MHz transducer system. Optical measurements validated theoretical predictions that (1) slope value is a function solely of scatterer size; (2) intercept value is a function of scatterer size and concentration; and (3) midband fit value increases as scatterer concentration increases, and, to a lesser extent, as size increases. These results were obtained under relatively ideal conditions of minimal attenuation and scatterer spacing (not closer than two scatterer diameters) and were consistent with the assumptions underlying the scattering theory.

Humans↗
PubMed1994

Intimal hyperplasia producing thrombus organization in an experimental venous thrombosis model.

PURPOSE: A venous thrombosis animal model demonstrated similarities between intimal hyperplasia and thrombus organization. This has prompted the evaluation of a hypothesis that intimal hyperplasia may be the mechanism for thrombus organization in veins with normal pressure. METHODS: Thrombi were produced in surgically exposed jugular veins of anesthetized, 18 to 20 kg pigs. Thrombosis was induced by a combination of devascularization, electric injury produced by a low amperage, direct current, and permanent partial ligation (50% diameter reduction). Vein segments were harvested at 0, 1, 2, 7, 14, and 60 days and histologically examined for fibrin, red blood cells, platelets, smooth muscle cells, endothelial cells, elastic fibers, and collagen deposits. RESULTS: Forty vein segments in 20 pigs were evaluated. Luminal thrombi with thickened walls developed in all specimens. All luminal thrombi demonstrated partial spontaneous thrombolysis over the period of observation. Intimal thickening consisting primarily of smooth muscle cells by day 2 was apparent and progressed until about 2 weeks, when collagen deposits became prominent within the neointima. The neointima frequently comprised half the cross-sectional area of the veins. Endothelial cells were present in the intima as single cells or as lining for clefts formed within the thickened intima. CONCLUSIONS: Smooth muscle cell proliferation with collagen deposition characteristic of intimal hyperplasia seemed to be the mechanism of thrombus organization in the experimental thrombosis model used in this study in which extensive stimulation was used to produce thrombosis.

Animals↗
PubMed1994

Airway epithelial cell changes in rats exposed to 0.25 ppm ozone for 20 months.

The present study was designed to characterize and quantify morphologic changes occurring in rat intra-pulmonary airway epithelia after long-term exposure to a high ambient level of ozone. Fifteen rats were exposed to 0.25 ppm ozone for 20 months (5 hr/day, 7 days/week) and a control group of 15 rats were exposed to filtered room air. Many intra-cellular brown pigmented granules (presumed to be lipofuscin) were seen in both the control and exposed animals; however, more of these granules were observed in the bronchial and bronchiolar epithelia of the exposed animals. To detect DNA synthesis that occurred in airway epithelial cells during the repair process induced by ozone toxicity, bromodeoxyuridine (BrdU) was injected intraperitoneally one hour before animals were sacrificed; the BrdU-labeling index was evaluated immunohistochemically. There was no difference in the BrdU-labeling index between the groups, the airway epithelia of the ozone-exposed animals exhibiting tolerance to ozone toxicity. However, the epithelial populations in the airways were altered by ozone exposure, and regional differences were seen in the changes. In the exposed animals, mucous cells increased in the lobar bronchus. Calcitonin gene-related peptide-immunoreactive pulmonary endocrine cells and neuroepithelial bodies were more frequently observed in the terminal bronchioles of the exposed animals than in the controls, although there were no differences in the lobar bronchus. Moreover, one adenoma in the peripheral lung was found in the exposed animals, while no tumorous lesions were detected in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1994

Photokilling of T-24 human bladder cancer cells with titanium dioxide.

A photoexcited titanium dioxide surface has a strong ability to decompose water into hydrogen and oxygen. We have studied this effect in order to use it to kill cancer cells in vitro and in vivo. A distinct cell killing effect was observed on cultured T-24 human bladder cancer cells treated with titanium dioxide particles and 300-400 nm UV light irradiation. Titanium dioxide plus UV light also dramatically suppressed the tumour growth of T-24 cells that were implanted in nude mice. Cells cultured on the titanium dioxide electrode were also killed under UV irradiation when the electrode was anodically polarised, suggesting that photogenerated holes are involved in the cell killing. The cell killing effect caused by titanium dioxide particles plus UV light irradiation was significantly hampered in the presence of L-cysteine and catalase, scavengers of hydroxyl radicals and hydrogen peroxide respectively. Transmission electron microscopic observations showed the titanium dioxide particles to be distributed on the cell surface and inside the cells. These results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules. The possible application of photoexcited titanium dioxide particles to cancer treatment as a new anti-cancer modality is discussed.

Catalase↗
PubMed1994

Pulmonary endodermal tumor resembling fetal lung. The optically clear nucleus is rich in biotin.

Pulmonary endodermal tumor resembling fetal lung (PET) is a rare pulmonary neoplasm that may represent a distinctive form of pulmonary blastoma lacking the sarcomatous component. A peculiar histologic feature of PET is the presence in the morular area of optically clear nuclei (OCN), which commonly show false-positive immunostaining by the avidin-biotin peroxidase complex (ABC) method. Because recent studies have shown that the nuclei of an identical change seen in endometrioid adenocarcinoma of the ovary and endometrial glandular epithelium during pregnancy are rich in biotin, we conducted an investigation to see if the same was true of a PET occurring in a 45-year-old man. Only the OCN were positively stained when the tissue section was incubated with peroxidase-labeled avidin or streptavidin and developed in a chromogen solution. The reaction was completely blocked by pretreatment with free avidin. An identical nuclear staining pattern was observed when the antibiotin antibody was applied as the primary agent by the indirect immunoperoxidase method. The neoplastic cells were negative for estrogen and progesterone receptors in immunostaining on frozen tissue sections. Ultrastructurally, the OCN were occupied by filamentous substructures of chromatin measuring approximately 10 to 12 nm in diameter. These results suggest that the OCN in PET are part of the unique nuclear change of certain neoplastic and non-neoplastic cells in the body in which abundant biotin accumulates within the nucleus in association with the characteristically arranged chromatin substructure. Further study is necessary to determine whether the OCN generally develop under the influence of female sex hormones. When immunostaining by the ABC method or related techniques is performed in PET and certain other epithelial lesions, the possibility of false positivity in the OCN should be kept in mind to avoid any misinterpretation of the results.

Adenocarcinoma↗
PubMed1994

Effect of thyroid-stimulating hormone on cultured thyrocytes obtained from patients with Graves' disease and inhibitive effect by sodium iodide: a functional study.

Thyrocytes obtained from patients with Graves' disease were cultured for 3 days. This was followed by culture with 10 mU/mL thyroid stimulating hormone (TSH) (TSH group), TSH and sodium iodide (Nal group), or without (control group) for 3 additional days. On the 8th culture day, the amounts of intra- and extra-cellular cyclic adenosine monophosphate (cAMP), extracellular cAMP and thyroglobulin (TG), peroxidase (PO) activity, and cell numbers were measured. The amounts of intra- and extra-cellular cAMP correlated well. TSH increased the values of cAMP, TG and PO to levels higher than those of the control group. As the amount of Nal added to the medium increased, these values decreased. Addition of 10(-5) mol/L Nal lowered the value of cAMP only. When 10(-4) mol/L Nal was added, these three levels were lower than those of the TSH group and the value of cAMP was almost equal to that of the control group. On cell number, no difference was found between the cells cultured with TSH, TSH and Nal, and without TSH or Nal. When the thyrocytes were cultured with 1 mmol/L dibutyryl cAMP sodium salt or 8-bromoadenosine 3',5'-cyclic monophosphate instead of TSH, 10(-4) mol/L Nal did not lower the values of thyroglobulin and peroxidase activity. These results suggest that the Nal blocks the intracellular signal transduction provoked by TSH, only at the cAMP production level.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Primary epithelioid malignant schwannoma of the lung.

This is the first documented report of a case of primary malignant nerve sheath tumor of the lung showing an epithelioid malignant schwannoma. A 55 year old Japanese female underwent lobectomy of the middle lobe of the right lung because of a large, rounded tumorous shadow found on chest X-ray film. Light microscopic examination of the neoplasm disclosed an epithelioid malignant schwannoma with foci having a spindle-cell sarcomatous pattern. The neoplastic cells were positive for S-100 protein and neuron specific enolase by the immunoperoxidase method. Transmission electron microscopy showed basement membrane-like material surrounding the neoplastic cells and long spacing collagens in the interstitial spaces. The patient died of a recurrent tumor in the right hemithorax 5 months after undergoing lobectomy. An autopsy revealed no primary site of the neoplasm outside the lung. Furthermore, there was no evidence of neurofibromatosis.

Female↗
PubMed1994

Perfusion reserve of coronary collateral circulation and its significance in the development of exercise-induced ischemia in patients with multivessel disease.

To assess the perfusion reserve of coronary collateral circulation, we analyzed exercise-stress tomographic thallium-201 myocardial images in 12 patients who had total occlusion in the right coronary artery (RCA) or left circumflex coronary artery (LCX) with well-developed collateral circulation and 90% stenosis in the left anterior descending coronary artery (LAD). In 6 of the 12 patients, the collateral circulation was non-jeopardized (group A). In the remaining 6 patients, the collateral circulation was jeopardized (group B). All 6 of the patients in group A had an exercise-induced decrease in thallium uptake in the segments supplied by the occluded RCA or LCX with collateral circulation, and 3 (50%) of these 6 also showed a decrease in thallium uptake in the segments supplied by the LAD. All 6 of the patients in group B also had an exercise-induced decrease in thallium uptake in the segments supplied by the occluded RCA or LCX with collateral circulation, but none showed a decrease in thallium uptake in the segments supplied by the LAD. In conclusion, the perfusion reserve of collateral circulation is equal to or less than 90% stenosis and myocardial ischemia occurs first in the collateralized segments during exercise in patients with jeopardized collateral circulation.

Adult↗
PubMed1994

[Adrenal cyst with an immunohistochemical evidence of mesothelial origin. Report of a case].

A case of adrenal cyst with an immunohistochemical evidence of mesothelial origin is presented. A 73-year-old Japanese woman was referred to our hospital with a complaint of left flank pain. The diagnosis of left adrenal cyst was made based on the radiographic and hormonal examinations. The adrenal cyst was removed surgically. Histological examination revealed that the cyst was lined with either a single layer of squamous or cuboidal cells. In immunohistochemistry testing, the cells were positive for keratin and carbohydrate antigen 125, while they were negative for epithelial membrane antigen, vimentin, desmin, and factor VIII related antigen. Thus, the present case was classified as epithelial cyst of mesothelial origin.

Adrenal Gland Diseases↗
PubMed1994

Protein C deficiency found in a patient with acute myocardial infarction: a single base mutation 157 Arg (CGA) to stop codon (TGA).

Protein C has an important role in the regulatory mechanisms of coagulation and fibrinolysis. In patients with heterozygous protein C deficiency, there is an increased risk for thromboembolic disease, especially in the venous system. We describe a patient with protein C deficiency presenting with an acute myocardial infarction (AMI). Direct sequence analysis of the whole protein C gene detected a single base mutation at exon 7; 157 [Arg(CGA) to stop codon (TGA): 6182 C to T]. Thus, the patient was suspected to have a deficiency of the protein C heavy chain molecule, resulting in both a low protein C antigen and activity level. The mutation was also found in the propositus' son and was confirmed by differential termination of the primer extension (DTPE).

Base Sequence↗
PubMed1994

[A case of lipoid pneumonia showing a pulmonary nodule mimicking lung cancer].

A 49-year-old man was admitted to our hospital because of hemosputum, left chest pain and an abnormal shadow on chest X-ray. Computed tomography of the chest revealed a tumor-like shadow with a low density area in the left lower lung field. Ga scintigraphy revealed strong Ga uptake in the left lower lung. Fiberoptic bronchoscopy showed obstruction of subsegmental bronchi of it. B9+10. Neither transbronchial biopsy nor sputum cytology showed any malignant cells. Transcutaneous lung biopsy showed infiltration of foamy macrophages in alveolar spaces and lymphocytes and plasma cells in alveolar septa. Since there was a possibility of complicating lung cancer, and because of refractory hemosputum, the patient underwent left lower lobectomy. The cut surface of the resected left lobe showed the features of golden pneumonia with cavitation. The histological features of the resected specimen were those of lipoid pneumonia, and no cancer cells were detected.

Diagnosis, Differential↗
PubMed1994

[An improved method for determination of C-peptide levels in serum: pretreatment of test samples with anti-insulin antibody insolubilized with magnetic particles].

RIA using anti-C-peptide antibody has been employed for determination of C-peptide in serum. However, the level by this method is a sum of the levels of C-peptide and proinsulin, because anti-C-peptide cross-reacts with proinsulin. This time we developed an improved assay for C-peptide, in which a test sample is pretreated with anti-insulin antibody to eliminate proinsulin in samples before C-peptide assay. The assay procedure is composed of 3 steps; the first is the incubation of test serum with anti-insulin antibody insolubilized with magnetic particles to form a complex of proinsulin-anti-insulin antibody, the 2nd step is the centrifugation of the mixture to eliminate the complex and the last step is the assay for C-peptide by use of RIA kit in the supernatant. The assay is simple, sensitive and reproducible. Serum C-peptide level by this method is not influenced by the presence of proinsulin in test serum, even when as high as 9 ng/ml of proinsulin is contained. This assay revealed that a patient with insulinoma had normal level of serum C-peptide in spite of the extremely high level of proinsulin.

C-Peptide↗
PubMed1993

A comparative study of vascular proliferation in brain metastasis of lung carcinomas.

Because of the marked vascular proliferation seen in brain metastases of small cell carcinoma of the lung (SCCL), we studied the morphometric and immunohistochemical characteristics of proliferating vessels in metastases from 20 autopsy cases of SCCL with brain metastasis. These were compared with those in surgically resected brain metastases of lung carcinomas, including 6 cases of SCCL, 19 cases of adenocarcinoma and 5 cases of squamous cell carcinoma. Angiogenesis in the tumours was scored by the microscopic angiogenesis grading system (MAGS). The MAGS score for autopsy and surgical metastatic lesions was highest in SCCL. Histologically, many vascular glomeruloid structures were formed in the brain metastases of SCCL, and immunohistochemistry revealed that these lesions were composed of proliferating endothelial cells and pericyte/smooth muscle cells. Immunostaining for basic fibroblast growth factor, a potent angiogenic factor, showed immunoreactivity in the tumour cells, regardless of histological type, and in the surrounding glial cells. Complex autocrine and paracrine phenomena participate in the development of metastatic cerebral lesions with vascular proliferation.

Adenocarcinoma↗
PubMed1993

Acute hemodynamic effects of bunazosin in congestive heart failure--differing responses according to degree of cardiac dysfunction.

1. Hemodynamic responses to Bunazosin (BZN) in congestive heart failure (CHF) were evaluated for 6 hours (hr) in 30 patients (A, normal cardiac function; B, mild cardiac dysfunction; C, severe cardiac dysfunction). 2. For 6 hr after BZN, the increments of cardiac index (delta CI) and stroke volume index (delta SVI) with BZN were higher in groups A and B than in group C. 3. A significant positive correlation was observed between ejection fraction and maximum delta CI and SVI, and between % fractional shortening and maximum delta CI and SVI. 4. These data showed that BZN improved the hemodynamics of CHF patients and that patients in groups A and B responded well to this vasodilator, however, patients in group C did not.

Adrenergic alpha-Antagonists↗
PubMed1993

Prolonging discordant xenograft survival with anticomplement reagents K76COOH and FUT175.

The guinea pig heart, when transplanted into the rat heterotopically, is rejected within 30 min via activation of the alternative complement pathway. Natural antibody does not contribute to rejection. This xenotransplantation model was used to assess the effect of anti-complement reagents on discordant xenograft survival. In vivo administration of K76COOH (K76) to rats induced only slight suppression of factors B and D and a marked decrease of C3, leading to the depression of ACH50 (reflecting the potency of the alternative pathway). On the other hand, FUT175 (FUT) reduced C3 activity by about 80% and inhibited factor B activity nearly 100% < 1 hr after the administration, but inhibited factor D activity only marginally. FUT abrogated ACH50 for > 6 hr. Of note, the xenograft beating time was prolonged approximately 3 times by FUT but not by K76, suggesting that direct inhibition of plasma serine protease factor B results in the complete suppression of ACH50 and graft survival. The administration of both K76 and FUT resulted in the longest graft survival, but the effects of these reagents were abolished by additional antigraft antibody. Anticomplement reagents that block factor B and C3 are therefore effective for prolongation of discordant xenograft survival when the graft rejection is associated with the complement alternative pathway.

Animals↗