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Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 415 records · Page 23Linked to original sources
PubMed1994

The role of cell-mediated immunity in chickens inoculated with the cell-associated vaccine of attenuated infectious laryngotracheitis virus.

The cell-mediated immune responses of the chickens inoculated with the cell-associated (CA) ILT vaccine were studied. Lymphocyte blastogenic response was tested by MTT assay with spleen, thymus, bursa of Fabricius and peripheral blood lymphocytes of the vaccinated chickens. The blastogenic response of peripheral blood and spleen lymphocytes was enhanced by a T-cell mitogen. The CA vaccine induced an immunity satisfactorily in bursectomized chickens. To study the role of immune cells in the vaccinated chickens, the bursectomized chickens were inoculated intravenously with the splenic, thymic, bursal and peripheral blood lymphocytes of the vaccinated chickens. Protective effects were shown in the chickens received the splenic cells and peripheral blood lymphocytes, indicating that these play an important role in eliciting the protective effects of the CA vaccine. From these results, it was found that the immune mechanism with CA vaccine against ILT involves mainly cell-mediated immunity.

Animals↗
PubMed1994

Plasma concentration of atrial natriuretic peptide and brain natriuretic peptide during normal human pregnancy and the postpartum period.

Increases in blood volume are observed during normal gestation and these are reversed shortly after delivery. Although both atrial (A-type) natriuretic peptide (ANP) and brain (B-type) natriuretic peptide (BNP) have been described, the role of these peptides in pregnancy and the postpartum period are unclear. This study was designed to examine the effects of pregnancy, labour and delivery on plasma levels of ANP and BNP. Plasma levels of ANP and BNP were determined during normal pregnancy, 30 min after separation of the placenta (immediately postpartum) and between 5 and 72 h postpartum (late postpartum; puerperium). Since the assay sensitivity was 20 pg/ml plasma (for both ANP and BNP), values less than this were assigned a value of 20 pg/ml to calculate means. Plasma levels of ANP and BNP were significantly higher at term pregnancy than during the first trimester (ANP increased from 20 +/- 0.2 to 57 +/- 10 pg/ml (S.E.M.), P < 0.001; BNP increased from 25 +/- 2 to 49 +/- 9 pg/ml, P < 0.01). The plasma level of ANP then rose to 157 +/- 38 pg/ml 30 min after separation of the placenta, being significantly (P < 0.01) higher than that seen at term pregnancy. It declined significantly (P < 0.001) to 32 +/- 3 pg/ml in the late postpartum period. In contrast, the plasma level of BNP 30 min after separation of the placenta was 80 +/- 25 pg/ml, and increased to 116 +/- 17 pg/ml in the late postpartum period, significantly (P < 0.01) higher than the level at term pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Mature cystic teratomas of the ovary without fat in the cystic cavity: MR features in 12 cases.

OBJECTIVE: The diagnosis of mature cystic teratoma may be overlooked in the small number of cases that do not contain fat in the lumen of the cyst. The purpose of this study was to evaluate the MR appearance of mature cystic teratomas containing little or no fat and to determine the value of gradient-echo MR imaging for detection of small amounts of fat. MATERIALS AND METHODS: In a review of pathologic specimens of 78 mature cystic teratomas, we found 12 tumors without fatty fluid (sebum) in their cystic cavity. Histologically, a small amount of fat was present in the wall of the cyst in each case. We retrospectively reviewed MR images of these tumors. In seven tumors with small amounts of hyperintense tissue on T1-weighted MR images, opposed-phase and in-phase gradient-echo MR images were obtained in order to verify the presence of fat. RESULTS: All 12 lesions were hypointense on T1-weighted MR images and markedly hyperintense on T2-weighted images, indicating that the cystic cavity contained aqueous fluid. Fatty tissue was not identified in the lumen or wall of the cyst on MR images in five of the 12 tumors. In seven tumors, MR images showed small hyperintense areas in the walls of the cysts. These hyperintense signals were canceled on opposed-phase gradient-echo images. Characteristic MR findings for mature cystic teratoma, such as reversed chemical-shift artifact, gravity-dependent layering, or dermoid plug, were not observed in any of the lesions. CONCLUSION: MR images in some cases of mature cystic teratomas may show aqueous fluid within the lumen of the cyst. In such cases, detection of fat in the cyst wall, especially with gradient-echo MR imaging, may help to establish the diagnosis.

Adipose Tissue↗
PubMed1994

Calcitonin gene-related peptide-like immunoreactive motoneurons innervating the canine inferior pharyngeal constrictor muscle.

The percentage of the calcitonin gene-related peptide-immunoreactive motoneurons (Mn) in the nucleus ambiguus (NA) innervating the canine inferior pharyngeal constrictor muscle was examined using the cholera toxin B subunit-gold (CTBG) as a retrograde tracer and by immunohistochemistry. Labeled neurons with CTBG (CTBG MNs) from the thyropharyngeal muscle (TP) were located in the dorsomedial division of the rostral part of the NA and the average percentage of neurons with CGRP immunoreactivity was 70.3%. CTBG MNs from the cricopharyngeal muscle (CP) were located in the dorsal division of the rostral part of the NA and the average percentage of neurons with CGRP immunoreactivity was 21.2%. This low percentage of CGRP immunoreactivity is noteworthy and supports the idea that the CP is a particular striated muscle in function and innervation manner.

Animals↗
PubMed1994

Differential binding of pp60c-src and pp60v-src to cytoskeleton is mediated by SH2 and catalytic domains.

The transforming protein of Rous sarcoma virus, pp60v-src, and its normal cellular homolog, pp60c-src, differ not only in oncogenic potential but also in their subcellular localization and cytoskeletal binding ability. pp60v-src has been shown to stably associate with a detergent-insoluble cytoskeletal matrix, whereas pp60c-src does not. We have generated a series of precise deletion and truncations of the Src homology domains within pp60v-src and pp60c-src, based on the crystal and solution structures of these regions, to determine not only the region responsible for cytoskeletal association but also the mechanism accounting for the differential binding observed. Here we show that the SH2 domain, but not the SH3 domain, mediates cytoskeletal association of pp60v-src through a phosphotyrosine-dependent interaction. The ability to interact with the cytoskeletal matrix is regulated by the catalytic (SH1) domain. Truncation of the pp60v-src catalytic domain results in lower binding while removal of the catalytic domain of pp60c-src results in the acquisition of cytoskeletal binding similar to that of the analogous v-src construct. These results indicate that the SH2 and catalytic domains function coordinately to regulate the cytoskeletal association of pp60v-src and pp60c-src.

Animals↗
PubMed1994

Histochemical localization of carbonic anhydrase in the rat duodenal epithelium.

Rat duodenum was examined for light and electron microscopical localization of carbonic anhydrase (CA) activity by the histochemical Hansson's method. The absorptive epithelial cells and some goblet cells showed a distinct reaction for CA activity in the cytoplasm, and on the striated borders and lateral cell borders. Electron microscopy confirmed that the reaction precipitates for CA activity are intimately associated with the cytoplasmic side of the cell membranes on both the lateral cell infoldings and the microvilli composing the brush borders. But the epithelial cells on the crypts were not positive except for some unidentified cells which show the distinct reaction. The duodenum was divided into four segments from the proximal to the distal part, and the homogenized mucosa scraped from each segment were examined for CA activity by Maren's physiological method. It was found that the activity decreased from the proximal to the distal segments. The most proximal segment showed the highest activity, 10.4 +/- 2.1 UA/mg of protein and 1468.7 +/- 324.8 UA/g of wet weight, and the most distal segment of duodenum showed the lowest activity, 2.4 +/- 0.7 UA/mg of protein and 291.7 +/- 85.8 UA/g of wet weight. The significance of the localization of CA activity in the villous epithelium of rat duodenum was discussed in relation to the bicarbonate section.

Animals↗
PubMed1994

[Anxious depression and depressive neurosis].

Among the diseases which, though demonstrating a depressive state, have anxiety symptoms in the foreground but are not accompanied by severe psychomotor retardation, include anxious depression and depressive neurosis. This report presents a general outline of anxious depression and depressive neurosis, together with their diagnosis, clinical features and therapy. In view of the expected continuing increase in the frequency of these two diseases in the future, the need for multidisciplinary approach, not only for the proper and early diagnosis, including differential diagnosis, and treatment of these diseases, but also for their prevention is described.

Anxiety Disorders↗
PubMed1994

[Method of DNA extraction and mecA, femA and PBP2' in multi-drug resistant bacterial strains].

Recently, it has become more important to establish rapid and reliable methods for identifying bacterial species and their drug resistances because of the high incidence of nosocomial infection caused by multi-drug resistant bacteria. At first, several enzymes were tested to evaluate the efficacy of DNA extraction. N-acetylmuramidase, lysozyme and achromopeptidase were most effective to extract DNA from E. faecalis, E. faecium and S. aureus, respectively. After achromopeptidase extraction, the mecA gene was amplified by polymerase chain reaction (PCR) in clinically isolated MRSA (95 strains), MSSA (66), MRSE (methicillin-resistant S. epidermidis, 37), MSSE (methicillin-sensitive S. epidermidis, 1), S haemolyticus(5), S.hominis(1) and others (Enterococcus, Pseudomonas, and Streptococcus, total 45). PCR products were analyzed by agarose gel electrophoresis. The positive rates were 95% (MRSA), 1.5% (MSSA), and 97% (MRSE). The mecA gene was also positive in 2/2 of methicillin-resistant S.haemolyticus and 2/3 of methicillin-sensitive S.haemolyticus and 1/1 of methicillin-resistant S.hominis. The mecA gene was not detected in 45 non-Staphylococcal strains. MecA and femA gene by PCR and PBP 2' by IRMA were further detected in newly isolated MRSA (20 strains), MSSA(20), MRSE(14), MSSE(1) and S.simulans(2). Complete correlation between MPIPC susceptibility and mecA were found. The femA gene was positive in 39/40 of S. aureus, and 0/14 of S.epidermidis, 2/3 of S.simulans. PBP2' were positive in 20/20 of MRSA, 0/20 of MSSA, 14/14 of MRSE, 0/1 of MSSE, 1/1 of methicillin-resistant S.simulans, and 0/2 of methicillin-sensitive S.simulans. In conclusion, diagnoses of MRSA by simultaneous detection of mecA and femA gene as well as PBP2' are similarly useful because of their specificity and rapidity.

Bacterial Proteins↗
PubMed1994

Effects of estrogen and progesterone on platelet-activating factor acetylhydrolase activity in ovariectomised rats.

OBJECTIVE: To evaluate the effect of estrogen and progesterone on plasma platelet-activating factor acetylhydrolase (PAF-AH) activity in ovariectomized rats. METHODS: Plasma PAF-AH activity was examined in ovariectomized rats treated with 17 alpha-ethynylestradiol (0.25 mg/kg; 6 days) or medroxyprogesterone (50 mg/kg; 6 days). The intra- and inter-assay coefficients of variation for plasma PAF-AH activity were 2.5% and 4.4%, respectively. Plasma lipoprotein profiles on day 5 were determined with commercially available kits. RESULTS: Ovariectomized rats showed no significant change in plasma PAF-AH activity over a 14 day period. Estrogen decreased the PAF-AH activity up to 85%, and progesterone increased PAF-AH activity up to 44% in ovariectomized rats. There was a positive correlation between plasma PAF-AH activity and high density lipoprotein cholesterol (r = 0.96, p < 0.001). CONCLUSION: These data suggest that estrogen and progesterone exert an effect on plasma PAF-AH activity in ovariectomized rats, possibly via high density lipoprotein cholesterol.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1993

Cholinergic neurons contain Calbindin-D28k in the monkey medial septal nucleus and nucleus of the diagonal band: an immunocytochemical study.

The distribution patterns of choline acetyltransferase (CAT), as a marker for cholinergic neurons, and Calbindin-D28k (CaBP) immunoreactivities in the forebrain basal ganglia of the Japanese monkey Macaca fuscata were compared. Similar distribution patterns of CAT and CaBP immunoreactivities were found in the medial septal nucleus (MS) and the nucleus of the diagonal band of Broca (DBB). Double-labeling fluorescence immunocytochemistry revealed that most, but not all, cholinergic neurons were CaBP-immunoreactive in the MS and DBB. The results suggest that CaBP may play a role in the septohippocampal cholinergic neuron system of the monkey.

Animals↗
PubMed1993

Substance P-like immunoreactivity in the suprachiasmatic nucleus of the rat.

The content of substance P (SP)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) of rats was determined by enzyme immunoassay to evaluate the effect of light on SP-LI in the rat SCN. Male rats were kept under various lighting conditions: light-dark cycles, constant darkness, continuous light exposure for 24 h or light pulse interrupting constant darkness. Animals were also subjected to ocular enucleation. The present study showed that SP-LI in the SCN was unaffected by environmental lighting conditions or by bilateral ocular enucleation. Immunohistochemical studies also confirmed that SP immunoreactivity, which was found in the ventrolateral (VL) subdivision of the SCN, was not reduced significantly even after ocular enucleation. These results suggest that, in contrast to other neurotransmitters in the VL portion of the SCN such as vasoactive intestinal polypeptide (VIP), gastrin releasing peptide (GRP) and neuropeptide Y (NPY), SP level in the SCN is quite stable to light and arises from an area other than the retina.

Animals↗
PubMed1993

Cloning and expression of the chicken c-kit proto-oncogene.

The Kit protein is a cell-surface tyrosine kinase receptor encoded by the c-kit proto-oncogene. cDNA clones encoding chicken Kit were isolated from a chicken brain cDNA library, and the nucleotide (nt) sequence of a cDNA clone containing the entire protein-coding region was determined. The deduced amino acid (aa) sequence of chicken Kit shows 63% identity to mouse Kit, and suggests that chicken Kit shares common structural and functional features with mouse Kit. RNA blot analysis indicated that the expression pattern of the chicken c-kit transcript in chicken organs was similar to that of mouse c-kit in mice, suggesting that chicken Kit has biological roles analogous to those of mouse Kit.

Amino Acid Sequence↗
PubMed1993

Cytokines in the peritoneal fluid of patients with endometriosis.

OBJECTIVE: To determine which of the various cytokines interleukin-5 (IL-5), interleukin-6 (IL-6) and interleukin-1 (IL-1) are important in endometriosis. METHODS: Peritoneal fluid (PF) samples were taken from 55 women at the time of either laparotomy or laparoscopy, and were examined for the levels of IL-5, IL-6 and IL-1 using each cytokine specific sandwich enzyme-linked immunosorbent assay. Thirty-two patients had pelvic endometriosis, eight post-pelvic inflammatory disease, four advanced cancer, three adenomyosis, three benign ovarian tumor, and other diseases. Statistical analysis was performed with the Mann Whitney test, chi-square test or Fisher's test. RESULTS: Both IL-5 and IL-6 levels in PF specimens with endometriosis tended to be higher than normal, while the same specimens were mostly interleukin-1 beta (IL-1 beta) negative. Of great interest was the negative correlation between log (IL-5) and IL-6 (Fisher's test, P < 0.04). CONCLUSION: These findings support the concept that IL-5 and IL-6 but not IL-1 are associated with endometriosis.

Adult↗
PubMed1993

Suppression of cytotoxic T-lymphocyte activity during human pregnancy.

We have investigated alterations in Epstein-Barr virus antigen specific cytotoxic T-lymphocyte (EBV-CTL) activity during human pregnancy. EBV-CTL activity was determined by a modified EBV induced B-cell focus regression assay and was expressed in terms of a regression index (IR50), i.e. the initial cell concentration required to achieve a 50%-incidence of regression in EBV-infected cell culture. Increased values of IR50 indicate the suppression of EBV-CTL activity. In 113 human female T-cell leukemia type-I (HTLV-I) non-carriers, the IR50 values (mean +/- S.E.) in non-pregnant, pregnant (the first trimester, second trimester and third trimester of pregnancy) and puerperal women were 10.6 +/- 1.4, 16.1 +/- 1.1 (20.1 +/- 2.0, 14.8 +/- 2.0, 14.6 +/- 1.6), and 12.1 +/- 1.9 respectively. Among HTLV-I carriers, the IR50 values (mean +/- S.E.) were likewise 34.6 +/- 8.0, 87.4 +/- 5.2 (101.7 +/- 6.3, 88.3 +/- 8.4 and 79.5 +/- 9.2) and 39.2 +/- 7.1 respectively. This data demonstrate: 1) EBV-CTL activity was suppressed during pregnancy (P < 0.05), especially in the first trimester (P = 0.0003). 2). In HTLV-I carriers, this suppression was shown in the first trimester (P = 0.0002), in the second trimester (P = 0.0002) and in the third trimester of pregnancy (P = 0.0014) and 3). One month after delivery, this suppression had returned to the non-pregnant level in both HTLV-I non-carriers and HTLV-I carriers. Pregnancy therefore has a suppressive effect on antigen specific cytotoxic T-lymphocyte activity and this effect is amplified in HTLV-I carriers.

Adult↗
PubMed1993

Resistance of hypothalamic dopaminergic neurons to neonatal 6-hydroxydopamine toxicity.

We studied the effects of neonatal intracisternal administration of the 6-hydroxydopamine (6-OHDA) following desipramine pretreatment on dopaminergic (DA) neurons in the rat hypothalamus and substantia nigra by immunocytochemistry with an antiserum against tyrosine hydroxylase (TH). Neonatal intracisternal 6-OHDA injection induced almost complete loss of the TH-immunoreactivity in the substantia nigra and the caudate-putamen when examined at final (adult) stage. However, in this stage, no difference of TH-immunoreactivity was observed in hypothalamic DA neurons in the arcuate nucleus (A12), periventricular area (A14), zona incerta (A13), and posterior hypothalamic area (A11). In the initial (neonatal) stage after the 6-OHDA injection, nigral DA neurons started to degenerate in 12 h and were almost completely destructed in 96 h, but hypothalamic DA neurons did not show any degenerative change at any time examined. The route of the injection (cistern, third ventricle or lateral ventricle) of the toxin did not influence the distribution of damage. These data show that 6-OHDA is not equally toxic to all brain DA neurons in neonates, and that all hypothalamic DA neuronal groups resist the toxicity of 6-OHDA, despite their anatomical and functional differences.

Animals↗