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Biomedical subjects

M Nakai

Publications and source records attributed to M Nakai.

At least 289 records · Page 16Linked to original sources
PubMed1989

Expression of human immunodeficiency virus type 1 (HIV-1) gag antigens on the surface of a cell line persistently infected with HIV-1 that highly expresses HIV-1 antigens.

MT-4 cells persistently infected with human immunodeficiency virus type 1 (HIV-1) (MT-4/HIV-1) were recently isolated (K. Ikuta, C. Morita, M. Nakai, N. Yamamoto, and S. Kato, Japan. J. Cancer Res. (Gann), 79, 418-423, 1988). Mouse hybridoma cell clones producing monoclonal antibodies (MoAbs) to HIV-1 gag p24 and p18, and pol reverse transcriptase (RT) were isolated by using this MT-4/HIV-1 cell line for the screening of MoAb production by the immunofluorescence (IF) test. By indirect IF tests of acetone-fixed cells with these MoAbs, the IF intensities in MT-4/HIV-1 cells were found to be higher than those in the other HIV-1 infected cells, such as MOLT-4/HIV-1, HL-60/HIV-1, and U937/HIV-1 cells. Cell surface expression of the HIV-1 gag p24 and p18 antigens examined by IF and radioimmune techniques with these MoAbs revealed the p24 and p18 antigens to be expressed strongly on the cell surface of MT-4/HIV-1 cells and faintly on the cell surface of MOLT-4/HIV-1 cells, respectively. However, monoclonal antibody isolated in the present study failed to detect pol RT antigen on the surface of MT-4/HIV-1 cells. These results indicate that the gag p24 and p18 antigens are expressed, at least in part, on the surface of HIV-1-infected cells.

Antibodies, Monoclonal↗
PubMed1989

Eye movements following cortical stimulation in the ventral bank of the anterior ectosylvian sulcus of the cat.

Eye movements were induced by stimulating the ventral bank of the anterior ectosylvian sulcus (AES) of chloralose-anesthetized cats. Intracortical microstimulation of this cortex evoked centering movements of both eyes. The latency of eye movement was 45 ms (range 40-60 ms) and the intensity of stimulation was 33 microA (range 20-45 microA). The evoked eye movements persisted after ablation of the classical frontal eye field of both sides. These results suggest that the ventral bank of the AES is involved in the control of eye movements.

Animals↗
PubMed1989

Precise determination of the mitochondrial import signal contained in a 70 kDa protein of yeast mitochondrial outer membrane.

A major 70 kDa protein of the yeast mitochondrial outer membrane is coded by a nuclear gene, synthesized on cytoplasmic ribosomes, and transported to the mitochondrial outer membrane. In order to investigate in detail the information necessary for localizing the 70 kDa protein at the outer membrane, we have examined the intracellular and intramitochondrial location of fusion proteins which consist of various lengths of the amino-terminal region of the 70 kDa protein with an enzymatically active beta-galactosidase. The results indicate that the extreme amino-terminal 12 amino acids of the 70 kDa protein function as a targeting sequence, whereas the subsequent uncharged region (up to residue 29) is necessary for "stop-transfer" and "anchoring" functions. Moreover, we have found that a fusion protein which contained the amino-terminal 19 amino acids of the 70 kDa protein is localized on the outer membrane as well as in the matrix space. Changes in the dual localization of this fusion protein accompanied its overproduction or expression in a respiration-deficient yeast mutant.

Base Sequence↗
PubMed1989

Protein sorting between the outer and inner mitochondrial membranes: submitochondrial localization of cytochrome c1 whose presequence is replaced by the amino-terminal region of a 70 kDa outer membrane protein.

The amino-terminal region of a 70 kDa mitochondrial outer membrane protein of yeast and the presequence of cytochrome c1, an inner membrane protein exposed to the intermembrane space, are thought to be responsible for localizing the proteins in their final destinations after synthesis in the cytosol. Gene fusion experiments were used to identify signals that are responsible for protein sorting between the outer and inner mitochondrial membranes. The submitochondrial localization of cytochrome c1 whose presequence was replaced by the amino-terminal region of the 70 kDa mitochondrial outer membrane protein has been investigated. We have also used an in vivo complementation assay to determine whether or not a 70k-cyt c1 fusion protein is functional. Both the first half and all of the presequence of cytochrome c1 can be replaced by the amino-terminal 12 or 29 residues of the 70 kDa protein for transport to the inner membrane and functional assembly into succinate-cytochrome c reductase. However, replacements by the amino-terminal 61 residues of the 70 kDa protein result in exclusive localization of the fusion proteins to the outer membrane, and the fusions cannot be assembled into the enzyme complex. These data indicate that a mitochondrial targeting signal alone is sufficient to direct cytochrome c1 of mature size to the inner membrane.

Animals↗
PubMed1989

[Detection of HTLV-I/ATLV by using the culture of lymph node lymphocytes with adult T-cell leukemia/lymphoma].

We cultured the cervical lymph node lymphocytes of a patient suffering from cutaneous T-cell lymphoma. His anti-ATLV antibody was positive by indirect immunofluorescent method (IF). ATLV was detected on these cultured cells by IF. Type C particles were observed in the cultured cells by electron microscopy. These particles were measured to be 60 to 120 nm in diameter with electron dense core, and were considered as ATLV. This case showed a possibility of detecting ATLV by culture of lymph node lymphocytes from such a patient.

Cells, Cultured↗
PubMed1989

[Comparative evaluation of markers with reverse transcriptase inhibiting antibody in human immunodeficiency virus type 1 infection].

To investigate a non-RI test which is equivalent to the reverse transcriptase inhibiting antibody test, a reverse transcriptase inhibiting antibody was compared to the absolute number of CD-4 or CD-8 cells or CD-4/-8 ratio and also to photodensitometric analysis for western blotting. There is no correlation of the reverse transcriptase with any test for cell numbers and their ratio. In photodensitometry, relative units of anti-p65 and anti-p51 were compared with reverse transcriptase inhibiting antibody. The reverse transcriptase inhibiting antibody showed a higher correlation to the relative unit of p65 antibodies than that of p51 antibodies. The photodensitometric analysis of western blotting for a serum test may be a possible method to find a prognostic marker in HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Absent effect of plasma vasopressin on rat brain blood flow during hemorrhage.

We investigated whether a reflex increase in plasma vasopressin level due to hemorrhagic hypotension affects brain blood flow. In 60 lightly anesthetized, artificially ventilated rats, the flow was determined with radiolabeled microspheres. We found excellent maintenance of blood flow throughout all brain regions during the hypotensive state (71 mmHg on average), and such maintenance of flow was not modulated at all by a supramaximal intravenous dose of the selective vasopressin V1-receptor antagonist [d(CH2)5 Tyr-(Me)]AVP. The latter finding also implies that the V1 antagonist failed to unmask the vasodilator type actions of V2 receptors on the maintenance of flow during hemorrhagic hypotension. These were true also when the cervical sympathetic bundles were severed bilaterally. The plasma level of endogenous vasopressin was increased during hypotension, ranging from 118 to 973 pg/ml. Despite this increase, the brain blood flow was entirely independent of the plasma vasopressin level in all the brain regions studied. We conclude that the brain circulation of rats can maintain its blood flow during hemorrhagic hypotension without any apparent contribution from a concomitant reflex increase in plasma vasopressin. Despite our negative results for the brain blood flow, the possible segmental effects of circulating vasopressin on the brain arterial caliber remain to be clarified under conditions of hemorrhagic hypotension.

Animals↗
PubMed1989

Characterization of a parvovirus isolated from the diarrheic feces of a pig.

A small DNA virus was isolated from the feces of a sow with diarrhea and identified as a parvovirus on the basis of its properties. The virus replicated preferentially in cell cultures of swine origin, including primary porcine thyroid gland and kidney cell cultures in which the cytopathic effect developed. The virus agglutinated erythrocytes of guinea pig, mouse and human group O but not these of chicken. The growth of the virus was inhibited by 5-iodo-2'-deoxyuridine. The virus was resistant to ether and heating at 56 degrees C for 30 min and stable at pH 3.0. The buoyant density of the infectious particles was 1.40 g/ml in CsCl density gradient, and the virions were 27 nm in diameter by electron microscopy. The viral protein seemed to be separated into four polypeptides with molecular weights of 81k, 70k, 66k and 62k daltons respectively. Cross serum neutralization test demonstrated that the virus was antigenically different from porcine parvovirus as well as bovine and canine parvoviruses. These findings and the survey on neutralizing antibody distribution indicated indirectly that another parvovirus which could be antigenically distinguished from well-known porcine parvovirus had been widespread among swine in Japan.

Animals↗
PubMed1989

Effects of ligation of the ductus deferens on the fowl epididymal region.

The effects of ligation of the ductus deferens on the epididymis in the fowl were studied histochemically and immunohistochemically to reveal the mechanisms of sperm disposal. At one week post-ligation, the lumina of the rete testes (RT) and the efferent ductules (ED) were distended and filled with densely accumulated spermatozoa. Macrophages and foreign-body giant cells were aggregated in and around the accumulations. The epithelium regressed in the initial portion of the RT with the invasion of fibroblasts and heterophiles into the lumen. The other part of the epithelium was penetrated by many spermatozoa. Numerous lymphocytes and plasma cells infiltrated into the interstitium. At 4 weeks, larger number of spermatozoa agglutinated in the lumen, and large masses of foamy cells and proliferated connective tissue protruded into the lumen. At 8 weeks, large masses of foamy cells were noted. The connecting ductules or the epididymal duct showed no marked changes after ligation. The epithelium of the ED showed weaker or no acid phosphatase activity after ligation. Immunoglobulin G-containing cells increased in number in the interstitium. These results showed that ligation of the ductus deferens in the fowl causes granuloma in the RT and ED, and that epithelial cells, macrophages and granuloma are engaged in the removal of spermatozoa. The participation of antibody is suggested in the sperm disposal processes.

Animals↗
PubMed1989

[Studies on the retentive force of clasps. 1. An effect of the material and technician].

Wire clasps and cast clasps are the most common retainers for removable partial dentures. The purpose of this study was to investigate the differences in the material and the variation among individual technicians in the retentive force of both clasps. The clasps were made in accord with the clinical method for experimental metallic model of the left mandibular second premolar and the retentive force of each clasp was measured by a pull-out test. The results were as follows: 1. Both types of clasp showed a large variation in the retentive force among the technicians, but no particular tendency was observed in the differences between wire and cast clasps. 2. There was no significant difference between the two types of clasp in the retentive force. 3. Due to the differences in individual technical skills, it seems to be difficult to make wire clasps with a standardized retentive force.

Denture Design↗
PubMed1989

Effect of arotinolol on hemodynamics and plasma atrial natriuretic peptide at rest and during stress in spontaneously hypertensive rats.

We investigated the effects of chronic treatment with arotinolol, a beta-blocker with weak alpha-blocking potency, on hemodynamics and plasma levels of catecholamines and atrial natriuretic peptide (ANP) at rest and during stress in spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. At rest, arotinolol treatment decreased mean arterial pressure (MAP), cardiac index (CI) and heart rate (HR), with no changes in total peripheral resistance index or regional hemodynamics in SHR. Acute stress caused more remarkable hemodynamic changes in SHR. During stress, arotinolol decreased MAP, CI and HR, and reduced myocardial and skeletal muscle flow and splanchnic, renal, cerebral and cutaneous vascular resistance in SHR. Arotinolol's effects were much less in WKY. Stress also increased the plasma catecholamine and ANP levels in SHR. Arotinolol raised these hormones in both strains at rest and in SHR during stress. Thus, arotinolol treatment exerted greater suppressive effects on the resting and stressed hemodynamics in SHR, with associated increases in the plasma catecholamine and ANP levels.

Adrenergic beta-Antagonists↗
PubMed1989

Histological study on seminal plasma absorption and spermiophagy in the epididymal region of domestic fowl.

Absorption of seminal plasma and spermiophagy in the fowl epididymal region were studied ultrastructurally and histochemically. Epithelial cells of the rete testis had sparse coated vesicles and rarely showed spermiophagy. Many macrophages in the lumen of the rete testis actively phagocytosed spermatozoa. Nonciliated cells in the proximal efferent ductules had well-developed microvilli, coated vesicles, numerous tubular structures, and lysosomes in their apical cytoplasm. They rarely contained fragments of spermatozoa. Intense alkaline phosphatase activity was observed at the luminal borders of these cells. Ciliated cells had no features indicating active absorption of seminal plasma. Epithelial cells of the connecting ductules and epididymal duct had numerous microvilli, a few vesicles, and small lysosomes. They did not contain spermatozoa. Intense acid phosphatase activity was observed on the luminal and lateral surfaces of the epithelial cells of the connecting ductules and epididymal duct. After injection of horseradish peroxidase into the excurrent ducts, a large amount of reaction product was detected in the vesicles and tubular structures of the nonciliated cells of the proximal efferent ductules. These results suggest that the absorption of seminal plasma occurred mainly in the efferent ductules, and that spermiophagy by macrophages occurred in the rete testis in the fowl epididymal region.

Absorption↗
PubMed1989

[Clinical study of combination chemotherapy with mitomycin C, vindesine and cisplatin (MVP therapy) in advanced non-small cell lung cancer].

Thirty-seven patients with inoperable non-small cell lung cancer were treated with the combination chemotherapy (MVP therapy) with mitomycin C (8 mg/m2), vindesine (3 mg/m2 X 2) and cisplatin (60 mg/m2). The partial responders were 13 cases (35%), and the median survival time was 271 days. In this study the cisplatin dose was less than in any other report of "MVP" therapy. But both the response rate and the median survival time did not differ from those reported elsewhere. The side effects (bone marrow suppression, renal toxicity, etc.) were mild, and did not prevent the continuance of this therapy. Thus, we could repeat more than 6 courses of "MVP" therapy for 8 patients. Nowadays, it is difficult to obtain complete responders with any chemotherapy for inoperable non-small cell lung cancer. To prolong lives of patients and maintain good quality of life, we recommend chemotherapy with low toxicity in often-repeatable courses.

Adult↗
PubMed1989

Effects of non-Newtonian blood and metabolic states of the blood and vessel wall on the optimum design of single vessels and the vascular bifurcation.

Employing the optimality principle, we attempted to predict the effects of non-Newtonian blood and the metabolic states of individual vessel segments on the optimum vascular design. Our results implied that irrespective of the vessel caliber, the optimum flow rate of non-Newtonian blood through a cylindrical vessel is less than that of Newtonian blood by not more than some 12-13%, even though the non-Newtonian nature is within the pathologically-realistic highest range. Non-Newtonian blood does not exert the slightest degree of influence on the optimum geometry of the vascular bifurcation. In contrast, as the metabolic state of the vessel wall overwhelms that of the blood, the optimum flow through the cylindrical vessel becomes markedly increased: the optimum relative caliber of the branch of the bifurcation decreases and the optimum branching angle increases.

Blood↗
PubMed1989

[A case of pseudolymphoma of the lung with cough and fever].

This case report presents a 48-year-old woman who had been suffering from cough and fever for 5 years. A large mass in the right lung was pointed out. Even after various examinations, we couldn't resolve the difficult diagnostic problems involved, but it was clear that there were no signs of a malignant tumor. We suspected a large benign tumor or pulmonary sequestration. Right lower lobectomy was performed and histological examinations of the resected tumor revealed lymphoproliferative disorder. Microscopic examinations of the specimen disclosed monotonous lymphoid cells proliferation (small to medium size) without definite lymph follicles or germinal centers. Lymph follicles were clearly demonstrated with the immunoperoxidase method. These findings were interpreted to be consistent with what has been recently called pseudolymphoma of the lung and prompted discussions on the reasonableness of criteria for the diagnosis of various pseudolymphoma and effective immunological examinations for the clarification of the etiology.

Complement System Proteins↗
PubMed1989

[Three-dimensional display of structures and lesions in the brainstem using a personal computer].

The method of three-dimensional reconstruction of structures and lesions in the brainstem was developed by using a personal computer to visualize the affected sites in some cranial nuclei and long tracts. Outlines of brainstem structures and lesions were digitalized manually by tracing the atlas of the human brainstem and CT or MR images. Four outlines of the brainstem, the medulla, lower pons, upper pons and midbrain, and the outlines of any parenchymal structures were taken at every point 2 mm in thickness. These were used as the standard visualization of the atlas. The CT and MRI, which show outlines of the lesions, were taken on the vertical planes to the floor of the fourth ventricle, one of which included the fastigium, at every point 3 to 5 mm in thickness. These two kinds of outlines, taken from the atlas and the CT/MRI, were reconstructed three-dimensionally with commercial 3-D software. It took only 20 to 25 minutes for the digitalization and the 3-D reconstruction. Three-dimensional display of small structures, which were difficult to identify on CT or MRI, and lesions would enable the visualization of their anatomical relations and make possible the detection of the affected sites, not only in the axial but in the longitudinal direction. Correspondence between the affected sites on 3-D and the neurophysiological examinations (ABR, SSEP) confirms that our 3-D method is adequate for use in the anatomical diagnosis of affected sites in any small structure in the brainstem.

Brain Diseases↗