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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 577 records · Page 32Linked to original sources
PubMed1993

Chondroitin sulfate iron colloid as MR contrast agent in differentiation between hepatocellular carcinoma and adenomatous hyperplasia.

Using a 1.5 T MR imaging unit, T1- and T2-weighted images were obtained before and after i.v. administration of chondroitin sulfate iron colloid (CSIC) in order to differentiate hepatocellular carcinoma (n = 20) from adenomatous hyperplasia without atypia (n = 16). Differentiation was made from the tumor-liver contrast to noise ratio (CNR) and visual evaluation of the nodule, with reference to signal intensity relative to that of the surrounding liver. The CNR of adenomatous hyperplasia was on T1-weighted images significantly decreased after CSIC administration (p < 0.01). On T2-weighted images, there was no significant difference in CNR after CSIC administration. On the other hand, the CNR of hepatocellular carcinoma was significantly increased after CSIC administration on both T1- and T2-weighted images (p < 0.01). CSIC reflects intratumor reticuloendothelial cellular functions, and is therefore useful in differentiating hepatocellular carcinoma from adenomatous hyperplasia without atypia.

Carcinoma, Hepatocellular↗
PubMed1993

Human space experiments in SL-J: preparation and conducted.

This experiment investigated how human beings achieve visual stability during body movements, including fine motion on the ground. When humans are exposed to an environment with different gravity vectors, the programmed behavior on the ground must be changed, that is, it is reprogrammed. This is called habituation or familiarization. This experiment focuses on visual, vestibular and somatosensory perception coordination and how it changes in microgravity as compared to a 1-G environment. We examined these issues under microgravity during the mission Spacelab Japan [correction of Japane] (SL-J) mission with the cooperation of the Japanese Payload Specialist (PS), Dr. Mohri. In this paper we describe how the first human life science experiments were conducted and how the data processed is being.

Adaptation, Physiological↗
PubMed1993

[Streptomycin-induced severe aplastic anemia successfully treated with high-dose methylprednisolone pulse therapy and rhG-CSF].

An 83-year-old male was admitted with pulmonary tuberculosis. He was started on rifampicin, isoniazid, and streptomycin (SM). The hematological data at 12 weeks after the treatment showed pancytopenia (RBC: 2.14 x 10(6)/microliters, Hb: 7.2g/dl, Plt: 1.8 x 10(4)/microliters, WBC: 700/microliters). All the above medicines were discontinued and he received bolus methylprednisolone (bmPSL) and recombinant human granulocyte-colony stimulating factor (rhG-CSF). After 3 cycles of bmPSL, red blood cells and platelets gradually increased. White blood cells also increased in response to rhG-CSF. Bone marrow aspirate and biopsy specimens showed normocellularity, indicating recovery from aplastic anemia. Drug lymphocyte stimulation test was positive for SM.

Aged↗
PubMed1993

Comparative changes in microvasculature and bone during healing of implant and extraction sites.

The acquisition and maintenance of biological fixation of dental implants are achieved by a rapid and regenerative response of the recipient tissues, especially the vascular and osseous elements. This sequential response is described from initial osteogenesis through remodeling up to 20 weeks after implantation in Macaca fuscata monkeys. The sequential changes in the microvasculature and bone formation in three-dimensional bone-vasculature microcorrosion casts are studied by means of a plastic injection method devised by the author. Micrographs derived from microcorrosion casts reveal that all soft tissues (blood vessels walls, marrow, collagen fiber cells and the like) have been digested, leaving spaces once occupied by these elements, bone, and polymeric material that filled the blood vessels at death. The effects of biomaterial choice, general implant configuration, and interface configuration and material were sequentially analyzed. The effects of one- and two-stage healing variables were not analyzed. The Macaca fuscata monkeys were used for SEM examination of both bioinert and bioactive dental implant materials. The objective of this paper is to describe osseous healing at an implant interface, and compare it with osseous healing in tooth extraction sockets by use of a similar research approach in identical animal models.

Alveolar Process↗
PubMed1993

In vitro and in vivo analysis of cellular origin of cervical squamous metaplasia.

We have previously shown that cultured normal human endocervical cells (HENs) form epithelium resembling squamous metaplasia in vivo. To analyze the cellular origin of squamous metaplasia, the cytokeratin and mucin expression and morphological features of HENs in monolayer cultures and in implants beneath the skin of nude mice were examined. Primary HENs had two distinct morphological phenotypes in vitro pleomorphic epithelial cells and keratinocytelike cells. Using a panel of monoclonal antibodies for various cytokeratins (CKs), we observed that the pleomorphic cells, which were the primary outgrowths, expressed CK7 and CK18 and produced mucin, suggesting their origin to be the mucosecretory columnar cells (CCs) of the endocervix. Keratinocytelike cells were observed in proximity of the CC-like cells after a few days of HEN culture. Interestingly, these cells were homogeneously negative for CK7 expression, as for native reserve cells (RCs), and homogeneously positive for CK13 expression with the antibody that is specific for RCs. During early passages, the culture consisted mostly of the RC-like keratinocytelike cells, and in the late passages, the CC-like cells were predominant. HEN implants in nude mice morphologically formed epithelia similar to immature squamous metaplasia and showed variable CK18 expression. Moreover, they showed homogeneous CK13 expression throughout all layers and expressed mucin and CK7 in the suprabasal cells. The possibility that the HEN culture was originally a mixed population of CCs and RCs, that we failed to detect, cannot be eliminated. Our results support the more likely view that the endocervical simple epithelia, which form squamous metaplasia, are bipotential cells and undergo differentiation readily and reversibly to give rise to CC-like and RC-like cells in culture.

Adult↗
PubMed1993

[Sleep-disordered breathing in Japan: an overview].

Questionnaires were answered by 3,243 presumably healthy subjects who underwent regular medical checkups in four cities. The prevalences of risk factors for sleep-disordered breathing (SDB) were as follows; habitual snoring was reported by 13-16%, excessive daytime sleepiness by 8-9%, insomnia by 7-13% and systemic hypertension by 5-13%. Polysomnographic studies performed on some possible SDB cases who were selected by the presence of risk factors estimated that the average prevalence of SDB in the present population would be in the range of 1.14-1.94%. Secondly, questionnaires were sent to the main hospitals and institutes involved in the management of patients with SDB, asking about diagnostic criteria, number of SDB patients, management, effectiveness of treatment, etc. The total number of patients registered at those hospitals was 2,751 in 1991. Of the 132 patients who were followed for more than six months, the efficacies of body weight loss, medications, nasal CPAP and UPPP were compared. Based on the analyses of the 279 patients examined some tentative vriteria for diagnosis and for treatment are proposed.

Female↗
PubMed1993

[Significance of Tc-99m pyrophosphate accumulation in unstable angina: clinical characteristics and evidence for myocardial stunning].

Tc-99m pyrophosphate (PYP) and Tl-201 simultaneous dual energy single photon emission computed tomography (SPECT) were performed for 33 patients with clinically diagnosed unstable angina. Twenty-two patients (76%) showed PYP accumulation in the myocardium (PYP+group). Clinical features, types of unstable angina, electrocardiographic changes during and after the anginal attack, and serial creatine kinase (CK) sampling data were reviewed and compared in the 2 groups. Selective coronary angiography was performed in all patients, and contrast left ventriculography was carried out in 29 patients both in unstable and stable states. In the study of left ventriculograms, the ejection fraction (EF) was calculated by the area-length method and the wall motion abnormality index was calculated by the centerline method. The PYP(+)group differed significantly from the PYP(-)group in several features as follows: 1) the "new angina at rest" type of unstable angina was more frequent in the PYP(+)group than in the PYP(-)group. The ratios of new angina at rest/effort angina (including new angina of effort and angina of effort with changing pattern) were 16/6; 2/9 for the PYP(+) and (-)groups, respectively (p < 0.05). 2) ST elevation during the heart attack was seen more in the PYP(+)group. The ratios of ST elevation/ST depression were 13/22 (59%); 5/22 (23%) for the PYP(+)group, and 2/11 (18%); 7/11 (64%) for the PYP(-)group, respectively (p < 0.05). 3) EF was improved in the PYP(+) group to the normal range. EF in the PYP(+)group changed from 57 +/- 12 in the unstable state to 62 +/- 11% in the stable state (p < 0.02), while that of the PYP(-)group showed no significant difference between the unstable state (59 +/- 9%) and the stable state (59 +/- 11%). 4) Wall motion abnormality index (WMI) in the PYP(+)group was poorer than in the PYP(-)group, but it improved markedly in one month to the same level as that of the PYP(-)group. WMI in the PYP(+)group in the unstable state (21.7 +/- 26.2) was worse than that in the PYP(-)group in unstable state (5.7 +/- 8.2) (p < 0.001). WMI in the PYP(+)group in the unstable state markedly improved in the stable state (from 21.7 +/- 26.2 to 8.4 +/- 19.8) (p < 0.025); whereas, WMI of the PYP(-)group showed no significant improvement (from 5.7 +/- 8.2 to 15.5 +/- 19.6). These data suggest that the area showing PYP(+) may represent stunned myocardium.(ABSTRACT TRUNCATED AT 400 WORDS)

Angina, Unstable↗
PubMed1993

[Successful treatment of diaphragm pacing-induced obstructive sleep apnea syndrome with nasal CPAP].

We report a 71-year-old female patient with primary alveolar hypoventilation syndrome who received diaphragm pacing (DP) and developed obstructive sleep apnea syndrome (OSAS). Application of nCPAP markedly improved her nocturnal hypoxemia. The monitored polygrams before and after the application strongly suggested that the main mechanism of OSAS was an imbalance of activity between upper airway dilator muscles and pump muscles. Moreover, paradoxical movement of the rib cage is not necessarily due to upper airway obstruction. Monitoring of tidal volume and arterial oxygen saturation is essential for the diagnosis of DP-induced OSAS.

Aged↗
PubMed1993

Stimulation of liver growth by exogenous human hepatocyte growth factor in normal and partially hepatectomized rats.

Human hepatocyte growth factor stimulates DNA synthesis by cultured rat hepatocytes. When human hepatocyte growth factor prepared from the culture medium of human embryonic lung fibroblasts was intravenously injected into normal rats and rats after 70% hepatectomy, it was detected in hepatocytes but not in nonparenchymal cells isolated 30 min after injection. Similar injections of human hepatocyte growth factor at 2-hr intervals for 10 hr significantly increased hepatic DNA content in normal rats at 48 hr, with increased hepatic content of putrescine, the essential polyamine for hepatic DNA synthesis after 70% hepatectomy, and activities of catalytic enzymes of putrescine synthesis at 6 hr almost to the levels in rats after 70% hepatectomy. Those levels in rats after 70% hepatectomy were further enhanced by similar injections of human hepatocyte growth factor starting immediately after surgery. Increased hepatic DNA content in normal rats and rats after 70% hepatectomy was also seen with recombinant human hepatocyte growth factor to a greater extent compared with that seen with human hepatocyte growth factor. In normal rats given recombinant human hepatocyte growth factor, 5-bromo-2'-deoxyuridine-labeled and mitotic hepatocytes were significantly increased in number at 26 hr but not at 48 hr. We conclude that exogenous human hepatocyte growth factor acts as a trigger and a promoter of liver growth to increase hepatic putrescine production in rats. Recombinant human hepatocyte growth factor is more potent than human hepatocyte growth factor in this action.

Animals↗
PubMed1993

Morphometric analysis of image distortion with rotational panoramic radiography.

We studied the image distortion of spherical objects that occurred during rotational panoramic radiography. We measured the magnification of height, width, perimeter and area, and calculated the circularity index to quantify the distortion. Spherical objects of different diameters were projected on the film. A complex relationship was found between the position and the horizontal magnification for each anatomical region. The object's size influenced the horizontal magnification to a considerable extent. The greatest changes in circularity occurred at the midline. This morphological distortion was caused by non-symmetrical projection during the scanning of these spherical objects, which resulted from the continuous changes in the scanning velocity and the position of the x-ray beam. This result suggests a complex distortion of the inner structures of macroscopic objects.

Humans↗
PubMed1993

[Proton magnetic resonance spectroscopy (1H-MRS) of peripheral blood lymphocytes in patients with sarcoidosis and interstitial pneumonitis].

We recently developed a method of proton magnetic resonance spectroscopy (1H-MRS) to measure the 1H-MR spectra of peripheral blood lymphocytes (PBL) using only 10(7) cells. We investigated the clinical feasibility of this method for evaluating disease activities in sarcoidosis and interstitial pneumonitis. PBL was separated from 10 ml of venous blood by differential centrifugation with Ficoll-Conray. Using a 90 MHz MR spectrometer (EX90, JEOL), the spectrum was obtained with 4000 times accumulation of 1H signals by single 70 degree pulses at 37 degrees C under spinning. Water signal was suppressed with the homo-gated decoupling sequence. The spectra were analyzed with Gaussian curve fitting. The spectra of patients with active disease showed significant increases in peak heights for (CH2)n and CH3 peaks compared with the control. The peak heights decreased after improvement of disease states. The changes in 1H-MR spectra suggested activation of PBL in patients with sarcoidosis and interstitial pneumonitis, since similar changes have been shown for cells activated with mitogens. Our preliminary results indicate that 1H-MRS may be useful to evaluate activation of PBL in sarcoidosis and interstitial pneumonitis.

Adult↗
PubMed1993

Preventive effect of gamma-glutamylcysteinylethyl ester on immunological cell injury in isolated rat hepatocytes with anti-rat liver plasma membrane antiserum treatment.

We studied the mechanism by which gamma-glutamylcysteinylethyl ester (gamma-GCE), which is rapidly transported into hepatocytes and converted to reduced glutathione (GSH), prevents immunological hepatic injury. The effect of gamma-GCE on cell injury, as estimated by release of transaminases from cells, and changes in phospholipase A2 (PLA2) activity and of GSH, Ca2+, and lipid peroxide (LPO) contents were examined in isolated rat hepatocytes treated with anti-rat liver plasma membrane rabbit antiserum (ALPMA) and compared with that of GSH. gamma-GCE prevented not only the release of transaminases from hepatocytes treated with ALPMA but also a decrease in GSH content, activation of PLA2, and increases in Ca2+ and LPO contents in the damaged hepatocytes. However, the preventive effect of GSH on these changes was weaker than that of gamma-GCE. In addition, gamma-GCE prevented the development of cell injury in ALPMA-pretreated hepatocytes. These results suggest that gamma-GCE prevents immunological cell injury in ALPMA-treated rat hepatocytes mainly by maintaining the integrity of the plasma membrane through its conversion to GSH within the cells.

Alanine Transaminase↗
PubMed1993

Microvascular architecture of the filiform papillae in primates and insectivores.

The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each of them supplied by a low and simple hairpin capillary loop. The aggregated filiform papillae of common squirrel monkeys were less frequent without any locational differences. Low filiform papillae of common marmosets and tree shrews were simpler in form, being arranged in a circle and supplied by a simple hairpin capillary loop. The filiform papillae of insectivores were not arranged in a circle. The filiform papillae of dwarf shrews were supplied by an incomplete capillary ring without a loop. With respect to species differences, the circularly arranged capillary loops in man were most complicated and highly developed. Microvascular architecture of the filiform papillae of insectivores was much simpler, different from those observed in primates.

Animals↗
PubMed1993

[A case of anterior mediastinal mature teratoma containing air because of penetration to the lung].

A case of anterior mediastinal mature teratoma containing air because of penetrating to the lung was reported. The patient was a 28-year-old woman. The chest X-ray film on admission showed a homogeneous mass in the anterior mediastinum. This shadow changed to cystic one after ten days later. The tumor was removed together with adhering part of the left lung and pericardium through median sternotomy. Histologically, the wall of cysts contained sebaseous glands, bronchial glands and pancreatic tissue containing both exocrine and endocrine elements.

Adult↗
PubMed1993

[A case of angiosarcoma presenting as ill-defined opacities on chest roentgenogram and hemothorax].

A 74-year old male was referred to the Tokai University Hospital for evaluation of abnormal opacities on a chest roentgenogram. Laboratory tests demonstrated leukocytosis, elevated ESR and CRP, elevated LDH, and hypoxemia. The chest roentgenogram demonstrated several ill-defined nodular infiltrates on the bilateral upper lung fields. In addition, a CT scan revealed bilateral pleural effusion which was found bloody on diagnostic thoracocentesis. Administration of antibiotics failed to improve lung infiltration or laboratory data. The patient died of respiratory failure on the 23rd hospital day. At autopsy, multiple ill-defined nodules, which were associated with alveolar hemorrhage, were scattered in the lungs bilaterally. Both hematoxylin-eosin and silver staining showed atypical cells of a vasoformative nature. Factor VIII related-antigen in the tumor cells was confirmed by the peroxidase-antiperoxidase method. These findings were consistent with angiosarcoma. The tumor foci were demonstrated in the lungs, pleura, kidneys, bone marrow, adrenal glands, and the gastrointestinal tract. The primary site of angiosarcoma, however, was not identified. Angiosarcoma, either primary or metastatic to the lungs, should be included in the differential diagnosis of multiple ill-defined nodular opacities associated with hemothorax.

Aged↗
PubMed1993

[Change in levels of specific terminal sugar residues of glycoproteins in sera of patients with malignant tumor].

Serum sialic acid (N-acetylneuraminic acid, NANA) levels significantly increased in all of patients with stomach cancer, colo-rectal cancer, breast cancer and pancreas cancer. However, the positive rate for serum NANA levels was 35 approximately 60% in these diseases. In contrast, a significant increase in serum NANA-galactose (NANA-Gal) levels was found in only stomach cancer and colo-rectal cancer; especially, the positive rate for serum NANA-Gal levels was 77% in colo-rectal cancer. In colo-rectal cancer, increased serum NANA-Gal levels were decreased after operation. But, in patients with colo-rectal cancer, changes in serum NANA levels following operation were variable. These results indicate that the assay of serum NANA-Gal level provides more important clinical significances for the specificity of cancer and the change of its status than that of serum NANA level.

Biomarkers, Tumor↗
PubMed1993

[Detection of minus strand HCV RNA in liver tissue by reverse transcriptase polymerase chain reaction (RT-PCR)].

Hepatitis C virus RNA in serum and liver tissue was examined in seven patients with liver cirrhosis by reverse transcriptase polymerase chain reaction method using primers for 5'-non-coding region. Plus strand HCV RNA were detected in serum and liver tissues in five of five patients who had HCV antibodies (C100-3 antibody and P22 antibody) and were not detected in two of two patients who do not have HCV antibody. Minus strand HCV RNA was detected in liver tissue of five HCV antibody positive patients. These results suggest that HCV are present and replicate in liver tissue in patients with liver cirrhosis.

Base Sequence↗