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Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 487 records · Page 27Linked to original sources
PubMed1998

[Method and evaluation of experimental retinal reattachment].

An animal model of retinal reattachment is needed to study experimental macular relocation and recovery of reattached retina. The purpose of this study was to develop and evaluate a simple technique of retinal reattachment. We used the right eye of 13 pigmented rabbits for this experiment. 3 weeks before the operation, the eyes underwent a gas induced vitreous compression with sulfur hexafluoride gas. Transcleral subretinal hydrodissecction was used to create a partial (60-70% of the whole retina) retinal detachment. Retinal reattachment was observed in ten eyes 18 hours after the operation. The dark-adapted electroretinograms (ERGs) were recorded in 3 rabbits from 3 days to 3 months after the surgery. Selected eyes were enucleated for histology. The amplitude of ERGs (a-wave and b-wave) were reduced to 30% and 40% of the control eyes on day 3. These waves were restored up to 70% and 80% of normal at 2 weeks and showed no significant changes thereafter. Degeneration and loss of photoreceptors in the early days after surgery as seen by light microscopy were almost completely restored to normal at 3 months after surgery. This model provides large retinal detachment and reattachment with minimized inflammatory response.

Animals↗
PubMed1998

[A recovered case of SLE with central nervous system involvement who relapsed presenting new symptoms associated with development of serum anti-Sm antibody].

A rare SLE patient with central nervous system involvement (CNS-SLE) who relapsed presenting new symptoms associated with the development of serum anti-Sm antibody and was then successfully treated with cyclophosphamide (CY) pulse therapy is presented here. A 47-years old housewife was admitted to Kushiro City General Hospital because of fever, limb erythema and drowsy consciousness in September 1995. On the basis of convulsion, proteinuria, leukopenia, thrombopenia, serum positive tests for both anti-nuclear antibody and anti-SSA antibody and low complement levels, as well as elevations of IgG index and IL-6 in the cerebrospinal fluid (CSF), she was diagnosed as having CNS-SLE. Serum tests for anti CL-beta 2 GPI antibody and lupus anticoaglant was negative. Serum test for HBs antigen was positive. She was treated successfully with methylprednisolone (mPSL) pulse therapy and plasma exchange (PE). Prednisolone was gradually tapered to the dosage of 17.5 mg per day and she was discharged in April 1996. She was re-admitted because of fever, an exacerbation of skin eruption and arthralgia in October 1996. Serum anti-Sm antibody was found to be positive. mPSL pulse therapy was not effective. On the basis of hallucination and elevations of IgG index and IL-6 in the CSF, a diagnosis of relapsed CNS-SLE was made. However the level of IFN-alpha in the CSF was normal. Although PE was not effective, CY pulse therapy was markedly effective.

Autoantibodies↗
PubMed1998

[Localized pulmonary infiltration in chronic myelomonocytic leukemia].

A 38-year-old woman who had been treated for refractory anemia was admitted with severe pancytopenia, persistent fever and splenomegaly in May 1995. The bone marrow biopsy revealed hyperplastic marrow with marked fibrosis. Shortly after admission, cardiac tamponade developed. Though low-dose Ara-C therapy successfully controlled the tamponade, no hematological recovery was obtained. Then a chemotherapy consisted of Ara-C, acrarubicin and M-CSF was done and the neutropenia was improved. However, progressive leukocytosis with monocytosis and splenomegaly subsequently developed. Thus, the disease was considered to progress to CMML. Localized pulmonary infiltrates associated with a cavity, a pulmonary artery aneurysm and a recurrent high fever developed in October 1995. Though invasive pulmonary aspergillosis was suspected, blood and sputa culture, as well as serological tests were negative. In February 1996, massive hemoptysis occurred and the patient died due to respiratory failure after an emergency right lobectomy of the lung. Pathological examination of the operated lung disclosed that the localized pulmonary infiltrates consisted of monocytoid cells. Infiltration of the monocytoid cells in the tissue surrounding the pulmonary aneurysm was also observed. However, no pathologic organisms were detected at all. Thus, the leukemic cells were considered to have infiltrated locally into the lung.

Adult↗
PubMed1998

Immunohistochemical detection of MUC2 mucin core protein in ulcerative colitis.

MUC2 mucin is predominantly expressed in the colon and is considered to play an important role in the protection of that organ. Recent findings suggested that MUC2 protein levels are significantly decreased in active ulcerative colitis (UC). We therefore performed an immunohistochemical study to reveal if the expression of MUC2 protein is altered in UC. Seventy-nine biopsy tissue specimens from 31 UC patients, along with normal colon tissues, were immunostained with anti-MUC2 mucin core protein monoclonal antibody (MoAb) CCP58 (IgG1). UC tissue specimens were divided into two groups based on the histological severity of inflammation, i.e., 64 with active inflammation (grades 2-5) and 15 without (grade 1). In the former group, 52 out of 64 (81.3%) tissue specimens contained sections of glands with a few cells positive for MoAb CCP58. These glands were small and consisted of MUC2 negative-short cells and a few positive cells without apparent mucus formation, considered to be immature regenerative glands. In contrast, the staining pattern was almost the same as that of the normal colon and no immature glands were seen in the group without active inflammation. The sections of immature regenerative glands with a few MUC2-positive cells were exclusively found in the UC tissues with active inflammation, but not in those without it, suggesting that the expression of MUC2 protein may be decreased in active UC.

Adolescent↗
PubMed1998

Changes in morphology of neuroblastoma cells treated with all-trans retinoic acid combined with transfer of the C-terminal region of the amyloid precursor protein.

Alzheimer disease is a progressive neurodegenerative disorder that is characterized by a loss of cognitive and memory functions. Amyloid fibrils deposited in neuritic plaque is mainly beta-amyloid protein (Abeta) that is derived from amyloid precursor protein (APP). The secreted form of APP, which is corresponded to N-terminal portion of APP, shows neurotrophic activities. On the other hand, Abeta and cytoplasmic domains of APP are thought to be neurotoxic. In order to investigate the effect of C-terminal fragment of APP covering Abeta and the cytoplasmic domain upon cell growth and differentiation, we established a stably transfected cell line producing the C-terminal 100 amino acid peptide of APR The transfected clones stained positively with anti-Abeta monoclonal antibody, TB-1. The growth rate of the transfected cells was not significantly different from that of mock-transfected cells or native NB39 cells. After treatment with all-trans retinoic acid (ATRA), mock-transfected cells extended neurite processes and showed neuronal-like differentiation, while a transfected clone overexpressing C-terminal fragment did not present neuronal-like morphology. These results suggest that ATRA-induced neurite extension may be suppressed by overexpression of the C-terminal fragment of APP.

Amyloid beta-Peptides↗
PubMed1998

[Hereditary macrothrombocytopenia].

A 19 year-old male was referred to our department because of macrothrombocytopenia. His platelet count was 73,000/microliter and giant platelets were observed in the peripheral blood smear specimen. Though he had been suffering from severe atopic dermatitis for four years, he seemed to be healthy without bleeding tendency. When he underwent a shunt operation for tetralogy of Fallot without any complication at nine-years old, thrombocytopenia was allegedly pointed out for the first time. Bone marrow aspiration revealed no abnormal findings with no chromosomal aberration. Normal platelet aggregation responses against adenosine diphosphate, epinephrine, collagen, and ristocetin were observed. The platelet adhesiveness (modified Salzman method) was slightly elevated. Unlike other reported syndromes associated with macrothrombocytopenia, his leukocytes had no inclusion bodies. His mother also had macrothrombocytopenia thus, this disorder was suspected to be hereditary.

Adult↗
PubMed1998

[Mass screening for prostate cancer--how to eliminate clinically insignificant cancer].

The ultimate aim of the mass screening program for prostate cancer is to decrease prostate cancer mortality, which can be demonstrated only in a well-designed and well-controlled trial comparing screened and unscreened populations. However, no trials have been performed to demonstrate the effect of this program. Some reports claimed that such a program includes the high possibility of detecting clinically insignificant cancer, for example, latent cancer. In this paper, early cancer detection and treatment in mass screening program are discussed.

Humans↗
PubMed1998

Serum levels of total and free prostate specific antigen in men on hemodialysis.

PURPOSE: The measurement of prostate specific antigen (PSA) is widely used in screening programs for early detection of prostate cancer. It has been recently shown that the ratio of free-to-total PSA in serum is lower in malignant than in nonmalignant prostatic disorders and, therefore, might be a parameter to improve screening specificity. We determine the influence of renal failure on serum levels of total and free PSA, and free-to-total PSA ratio. MATERIALS AND METHODS: Serum concentrations of total and free PSA, and free-to-total PSA ratio were measured in 93 men undergoing hemodialysis. The control group consisted of 2,298 healthy blood donors. RESULTS: Serum levels of total PSA were not significantly different between control and hemodialysis patients. Serum free PSA and free-to-total PSA ratio of hemodialysis patients were significantly higher than those of controls (p <0.01 to 0.001). However, these values did not change in uremic patients after hemodialysis. Although serum total and free PSA levels increased with each decade of age, they did not correlate with age in hemodialysis patients. CONCLUSIONS: Serum free PSA as well as total PSA is not eliminated by hemodialysis, and elevated levels of free PSA and free-to-total PSA ratio in hemodialysis patients may be caused by a concomitant decrease in binding proteins. The reference ranges for total and free PSA, and free-to-total PSA ratio may not be necessarily beneficial in hemodialysis patients.

Adult↗
PubMed1998

[Clinical study on prostate cancer initially presenting with disseminated intravascular coagulation syndrome].

We experienced five patients with prostate cancer with disseminated intravascular coagulation syndrome (DIC) at the first presentation at Gunma University Hospital and affiliated institutions between 1991 and 1997. Their average age was 68 years, average DIC score at the first presentation was 10 and prostate specific antigen (PSA) level was more than 700 ng/ml. All of them had multiple bone metastases. The therapy for DIC and hormonal therapy for prostate cancer were simultaneously started at the first presentation before prostate needle biopsy, but all patients died. The average number of days from the start of DIC to death was 685 days. The patients initially showed a good response to therapy, but their conditions soon aggravated. The prognosis was extremely poor, but some proper therapies lead to the prognosis which was equal to that of prostate cancer in Stage D2 without DIC.

Adenocarcinoma↗
PubMed1998

[A case of systemic lupus erythematosus developed with intestinal perforation].

A case of intestinal perforation associated with SLE is presented. A 54-year-old woman was diagnosed as having SLE twenty-five years ago when she had facial erythema, photosensitivity, oral aphtha, polyarthraliga, leukopenia, positive LE cell and positive antinuclear antibody. She had been treated with prednisolone and admitted to Kushiro City General Hospital because of one month history of fever and anorexia in February 1996. Laboratory findings did not reveal activity of SLE, and a diagnosis of urinary tract infection was made based on the findings of urinalysis. After severe diarrhea, disseminated intravascular coagulation (DIC) developed. A rectal perforation was revealed by endoscopic and radiological examination. An emergency laparotomy revealed necrosis of the rectum and sigmoidostomy was performed. The biopsied specimen of the rectum were diagnosed as gangrene of ischemic colitis histologically. Because of a penetration to the urinary bladder, an ureterocutaneostomy was performed. She died of sepsis and DIC on the 127th day of admission. Only 11 cases of intestinal perforation associated with SLE have been reported in Japan, and the association of vasculitis has been considered. In the present case, the prolonged use of prednisolone might cause the necrotizing ischemic colitis.

Female↗
PubMed1998

Efficacy of a left atrial procedure for treatment of chronic atrial fibrillation in elderly patients.

A simple left atrial procedure for atrial fibrillation (AF) was performed in 16 elderly patients (age over 70 years old) with chronic AF associated with mitral and/or aortic valvular diseases. Chronic AF was eliminated upon discharge in 13 out of the 16 patients (81%). Twelve of the 13 patients (92%) whose AF had disappeared recovered the atrial kick of their right atrium, and 9 patients (70%) recovered the atrial kick of their left atrium. A simple surgical procedure to the left atrium was effective in the treatment of chronic AF associated with mitral valve disease in elderly patients. This simple procedure is preferable to other methods for the elimination of chronic AF with mitral valve disease in elderly patients.

Aged↗
PubMed1998

[Regulation of integrin function in the metastasis of colorectal cancer].

Alterations in several classes of adhesion molecule have been implicated in the progression of colorectal cancer. Cell adhesion regulator (CAR) has been identified as a regulator molecule of integrin-dependent cell adhesion. We have explored the possible involvement of the CAR gene in colorectal cancer. Reverse transcription-PCR revealed that CAR expression was detected in normal colonic cells, whereas it was decreased or undetectable in 6 of 13 (46.2%) human colon cancer cell lines. Adhesion of HT-29 cells to extracellular matrix components was up-regulated by the introduction of CAR. CAR-transfected HT-29 cells showed a significantly reduced spontaneous metastatic potential in nude mice. In 14 of 30 cases (46.7%), CAR expression in cancer was less than one-tenth of that in matched noncancerous tissue. The tumor: normal ratio of CAR expression was significantly lower in patients with lymph node metastases than in those without (p < 0.01) and in patients with distant metastases than in those without (p < 0.05). CAR expression was significantly lower in more advanced Dukes' stage tumors (p < 0.05). Our results suggest that down-regulation of CAR expression may play an important role in the progression and metastasis of colorectal cancer.

Animals↗
PubMed1998

[The significance and limitation of prostate specific antigen in the mass screening for prostate cancer].

The ultimate aim of the mass screening program is to decrease the prostate cancer mortality, which can be demonstrated only in a well designed and well controlled trial comparing screened and unscreened populations. However, there are not any trials which prove the effectiveness of mass screening for prostate cancer. Among the 3 modalities, prostate specific antigen (PSA) had the highest sensitivity and positive predictive value. However, PSA had the 20% probability to diagnose incorrectly the patient with prostate cancer as a normal. PSA had 10% possibility to detect clinically insignificant cancer. It is important to inform subjects not only the significance but also limitation of mass screening by PSA.

Biomarkers, Tumor↗
PubMed1998

[Use of 99mTc-labeled myocardial perfusion agents in the Kanto-Koshinetsu area].

We sent out a questionnaire to investigate how the 99mTc-labeled myocardial perfusion agents are used in the Kanto-Koshinetsu area. Answers were obtained from 83 laboratories. Examinations using 99mTc-labeled agents were performed more frequently than those using 201T1 only in 10 of 83 laboratories. Main reasons for not using 99mTc-labeled agents were as follows: two injections required in the stress study, superiority of thallium-201 in the assessment of myocardial viability, a large amount of clinical data cumulated in thallium-201 imaging, and problems caused by abdominal uptake of 99mTc-labeled agents. Comparing purposes of the examinations using 201T1 and 99mTc-labeled agents, evaluation of myocardial viability was more common in 201Tl imaging, meanwhile, detection of myocardial ischemia was more common in imaging with 99mTc-labeled agents. It was pointed out that dual isotope imaging using 201Tl and 99mTc-labeled agents and simultaneous evaluation of myocardial perfusion and cardiac function are clinically feasible as new diagnostic procedures.

Heart↗
PubMed1998

Molecular mechanisms in the reversible regulation of morphology, proliferation and collagen metabolism in hepatic stellate cells by the three-dimensional structure of the extracellular matrix.

Hepatic stellate cells (vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, Ito cells) exist in the perisinusoidal space of the hepatic lobule and store 80% of the body's retinoids as retinyl palmitate in lipid droplets in the cytoplasm. Under physiological conditions, these cells play pivotal roles in the regulation of retinoid homeostasis; they express specific receptors for retinol-binding protein (RBP), a binding protein specific for retinol, on their cell surface, and take up the complex of retinol and RBP by receptor-mediated endocytosis. However, in pathological conditions such as liver fibrosis, these cells lose retinoids and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. The morphology of these cells also changes from star-shaped stellate cells to that of fibroblasts or myofibroblasts. The three-dimensional structure of ECM components was found to regulate reversibly the morphology, proliferation and functions of hepatic stellate cells. Molecular mechanisms in the reversible regulation of stellate cells by ECM imply cell surface integrin binding to ECM components followed by signal transduction processes and then cytoskeleton assembly.

Cell Division↗
PubMed1998

Morphological comparison and functional reconstitution of rat hepatic parenchymal cells on various matrices.

Four types of materials, type I collagen coat (Coat), acid-soluble type I collagen gel (Hardgel), pepsin-treated acid-soluble type I collagen gel (Softgel), and an extract of extracellular matrix of the murine Engelbreth-Holm-Swarm sarcoma (Matrigel), were used as matrices to culture rat hepatic parenchymal cells, and their morphological changes and adhesion were compared to the matrices by electron microscopic observations. Hepatic parenchymal cells cultured on Coat and Hardgel were extended and flattened, whereas cells cultured on Softgel and Matrigel assembled and formed aggregates. Such aggregates consisted of several hepatic parenchymal cells, with a recognizable bile duct-like alveolus on the inside. Morphologically, the aggregates were more spherical on Matrigel and oval shaped on Softgel. Microvilli of the cell surface were parallel to the matrix on Matrigel, but invaded into the gel on Softgel. Subsequently, investigation into how these morphological features affected the liver-specific functions, including secretion of albumin and induction of P450 by 3-methylcholanthrene, demonstrated that a high level of liver function was maintained in a long-term culture in hepatic parenchymal cells on Softgel. These results suggest that hepatic parenchymal cell interactions were stronger with Softgel than with Matrigel, and that Softgel appears to closely mimic the in vivo environment.

Animals↗