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Biomedical subjects

M Imai

Publications and source records attributed to M Imai.

At least 721 records · Page 40Linked to original sources
PubMedDate not supplied

Immunoglobulin A antibody against hepatitis B core antigen of polymeric and monomeric forms, as well as of IgA1 and IgA2 subclasses, in acute and chronic infection with hepatitis B virus.

Solid-phase radioimmunoassays using monoclonal antibodies were used to assay antibody to hepatitis B core antigen of immunoglobulin A class in terms of polymeric and monomeric forms, as well as of IgA1 and IgA2 subclasses, in the serum of persons infected with hepatitis B virus. The level of secretory immunoglobulin A antibody was significantly higher in patients with acute hepatitis (mean +/- S.E., sample per normal ratio = 29.2 +/- 1.9) than that in asymptomatic carriers (2.1 +/- 0.1), patients with chronic persistent hepatitis (3.5 +/- 0.5), patients with chronic active hepatitis (6.9 +/- 1.3) or patients with cirrhosis (5.8 +/- 1.1). In acute type B hepatitis, only polymeric immunoglobulin A antibody of either IgA1 or IgA2 subclass was detected. In contrast, in chronic infection, antibody to hepatitis B core antigen of IgA2 subclass was found in the polymeric form, but antibody of IgA1 subclass was detected in both polymeric and monomeric forms.

Antibodies, Monoclonal↗
PubMedDate not supplied

Changes in muscle size, architecture, and neural activation after 20 days of bed rest with and without resistance exercise.

Nine healthy men carried out head-down bed rest (BR) for 20 days. five subjects (TR) performed isometric, bilateral leg extension exercise every day, while the other four (NT) did not. Before and after BR, maximal isometric knee extension force was measured. Neural activation was assessed using a supramaximal twitch interpolated over voluntary contraction. From a series cross-sectional magnetic resonance imaging scans of the thigh, physiological cross-sectional areas (PCSA) of the quadriceps muscles were estimated (uncorrected PCSA, volume/estimated fibre length). Decrease in mean muscle force after BR was greater in NT [-10.9 (SD 6.9)%, P < 0.05] than in TR [0.5 (SD 7.9)%, not significant]. Neural activation did not differ between the two groups before BR, but after BR NT showed smaller activation levels. Pennation angles of the vastus lateralis muscle, determined by ultrasonography, showed no significant changes in either group. The PCSA decreased in NT by -7.8 (SD 0.8)% (P < 0.05) while in TR PCSA showed only an insignificant tendency to decrease [-3.8 (SD 3.8)%]. Changes in force were related more to changes in neural activation levels than to those in PCSA. The results suggest that reduction of muscle strength by BR is affected by a decreased ability to activate motor units, and that the exercise used in the present experiment is effective as a countermeasure.

Adolescent↗
PubMedDate not supplied

Overproduction of transcription termination factor Rho in Escherichia coli.

A plasmid system has been constructed which allows high-level expression of the rho gene of Escherichia coli under the control of the pL promoter and the N-antitermination regulatory system of bacteriophage lambda. The pL-directed synthesis of Rho crucially depends on the lambda N gene product and is promoted most effectively when this product is supplied from the N gene cloned on a separate compatible plasmid with a moderate copy number. The requirement for N can be circumvented partly, but not completely, by deletion of the region preceding the rho structural gene. Attempts were also made to optimize the construction of rho-expression plasmids by adjusting the orientation and location of pL and rho inserts on the pBR322 vector. With optimal conditions, Rho protein is overexpressed 100-fold and can become as much as 10% of the total cellular protein. Using this plasmid system, Rho can be purified with a yield of more than 20 mg from 10 g of induced cells.

Bacteriophage lambda↗
PubMedDate not supplied

Adrenoleukomyeloneuropathy presenting as cerebellar ataxia in a young child: a probable variant of adrenoleukodystrophy.

A child aged 5 years 7 months was diagnosed as suffering from adrenoleukomyeloneuropathy (ALMN). The first sign was ataxia, and high intensity lesions were observed in the cerebellar hemispheres on T2-weighted brain MRI. His condition progressed rapidly to a vegetative state in 1 year. When aged 7 years 3 months adrenal insufficiency supervened and his skin turned dark. Rectal biopsy revealed linear cytoplasmic inclusions in macrophages in the rectal membrane. At the age of 8 years 2 months, an analysis of very long-chain fatty acids of sphingomycin in plasma led to the final diagnosis. At the age of 10 years, cerebellar and cerebral atrophy were prominent and diffuse high intensity lesions were noted in the cerebellum and cerebrum. An onset below 9 years of age has not previously been documented in ALMN.

Adrenoleukodystrophy↗
PubMedDate not supplied

Multilocational hepatocyte transplantation for treatment of congenital ascorbic acid deficiency rats.

We attempted multilocational hepatocyte transplantation (HCTx) including hepatocyte-bearing polyurethane foam (PUF) to treat congenitally ascorbic acid (AsA) biosynthetic enzyme-deficient (ODS-od/od) rats. Hepatocytes isolated from the liver of congeneic rats were transplanted into the portal vein (Pv), spleen (Sp), omentum (Om), and mesentery (Ms). Hepatocyte-bearing PUF was transplanted into the Om and Ms. Experimental groups were divided into four groups (group I; Pv + Sp, group II; Pv + Sp + Om + Ms, group III; Pv + Sp + hepatocyte-bearing PUF, group IV; control). The average serum AsA level of the surviving rats in group II and III was significantly higher than that in group I 3 mo after HCTx. Histological examination showed small foci of surviving hepatocytes in the Om and Ms tissues and in the connective tissue in the PUF. ODS-od/od rats survived for a long time by multilocational HCTx.

Animals↗
PubMedDate not supplied

Developmental expression of cytochrome P450S within intrasplenically transplanted fetal hepatocytes.

Fetal hepatocytes were harvested at day 20 of gestation from spontaneously hypertensive rats (SHR) and then transplanted into recipient adult SHR spleens. Morphological examination of the recipient spleens revealed that, after 4 and 10 wk, large masses of hepatocytes were present in the red pulp with apparent cord-like structures. Larger batches of hepatocytes were observed in the spleens at 10 wk after than at 4 wk after transplantation. Of major significance was the fact that hepatocyte transplanted spleens were able to express several families of cytochrome P450 (cyto P450) proteins 2-10 wk after transplantation. Immunochemical determinations revealed that cytos P450 IA1, P450 IIB1, P450 p, P450 HLp, and P450 LA omega could be detected without any prior induction. All were intensely expressed 6 wk after transplantation; however, P450 IA1 and P450 IIB1 did not appear to be expressed by 2 wk after transplantation. Although cytos P450 p and P450 HLp did not appear to be expressed by 10 wk after transplantation, they were induced with dexamethasone at that time. Cyto P450 LA omega and peroxisomal acyl CoA oxidase were expressed 6 wk after transplantation in a 70% hepatectomized host. These results demonstrate that fetal hepatocytes can be successfully transplanted into the spleens of recipients and that the fetal hepatocytes appear to grow and develop cyto P450 metabolizing systems.

Animals↗
PubMedDate not supplied

Cloning and sequence analysis of cDNA encoding a precursor for human atrial natriuretic polypeptide.

Recent identification of natriuretic-diuretic activity in peptides isolated from human and rat atrial tissue implicates them in the control of extracellular fluid volume and electrolytic homeostasis. The presence of multiple forms of the peptides ranging from 3,000 to 13,000 molecular weight (MW) suggests they may all derive from the same precursor. The established amino acid sequence of alpha-human atrial natriuretic polypeptide (alpha- hANP ), a 28-residue peptide with potent natriuretic activity, provided the means to elucidate the structure of the precursor for alpha- hANP and the gene encoding it. Here we report the cloning and sequence analysis of the cDNA of human atrial mRNA encoding a precursor of alpha- hANP . The cDNA encodes gamma-human atrial natriuretic polypeptide (gamma- hANP ) of 13,000 MW, whose C-terminal 28 amino acid residues may be processed as alpha- hANP .

Amino Acid Sequence↗
PubMedDate not supplied

Selective absence of immunoglobulin A1 or A2 among blood donors and hospital patients.

A hemagglutination inhibition assay was developed for the determination of immunoglobulin A1 and A2 (IgA1 and IgA2) with subclass-specific rabbit antiserums. Among 93,020 apparently healthy blood donors, selective absence of IgA1 was found in six and that of IgA2 in 15, at a prevalence much higher than the absence of total IgA that was revealed by only one donor. Among 6800 hospital patients with various disorders, the absence of IgA1 was found in one with breast cancer and that of IgA2 in two with rheumatoid arthritis.

Adolescent↗
PubMedDate not supplied

Establishment of feeder-independent cloned caprine trophoblast cell line which expresses placental lactogen and interferon tau.

A feeder-independent cloned trophoblast cell line, HTS-1, was established from a mature placenta of Shiba goat (Capra hircus). During the growth phase, single HTS-1 cells exhibited ruffled membranes or lamellipodia often accompanied by elongated cell shape, indicating highly motile nature of the cells. At or near confluence, HTS-1 cells formed monolayers with few sign of cellular overlapping. Binucleate cells were found at a high frequency especially in the peripheral regions of monolayers. In small colonies and the monolayers, majority of HTS-1 cells assumed polygonally shaped cobble-stone like morphology characteristic to epithelial cells, although considerable variations in cellular morphology were observed despite of repeated cloning. Time-lapse video recordings of HTS-1 cells during culture revealed that not only the small colonies but also the monolayers near or at confluence were remarkably motile, often causing extreme elongation of the cells within them. The extremely plastic nature of HTS-1 cells in vitro is likely to be the reflection of the extraordinary capacity of caprine trophoblast cells to be stretched to extreme thinness in vivo as shown by electron microscopy. HTS-1 cells cultured on matrigel are highly invasive, and express MT1-MMP which, in the mouse, has been known to be expressed at the invasive edge of trophoblast both in vitro and in vivo. HTS-1 cells express placental lactogen (PL) and interferon-tau (IFNtau), as confirmed by immunocytochemistry, Western blotting and RT-PCR analysis. Both PL and IFNtau expression in the cells appeared to be down-regulated by cell-cell contact. In the medium conditioned by HTS-1 cells, the presence of secretory form of PL and IFNtau was confirmed by Western blotting. The HTS-1 cell line will serve as a useful in vitro model for the analysis of the molecular and/or cellular mechanisms underlying synepitheliochorial placentation in bovidae animals.

Animals↗
PubMedDate not supplied

Mortality from asthma and chronic bronchitis associated with changes in sulfur oxides air pollution.

Death certificates issued in Yokkaichi, Japan, during the 21 yr from 1963 until 1983 were surveyed to determine the relationship between changes in air pollution and mortality due to bronchial asthma and chronic bronchitis. The following results were obtained. In response to worsening air pollution, mortality for bronchial asthma and chronic bronchitis began to increase. Mortality due to bronchial asthma decreased immediately in response to improvement of pollution, whereas mortality due to chronic bronchitis decreased to the level in the control area 4 to 5 yr after the concentration of sulfur dioxide (SO2) began to satisfy the ambient air quality standard. In the polluted area, mortality due to bronchial asthma in subjects who were 20 yr of age was higher during the period in which higher concentrations of sulfur oxides were prevalent.

Adolescent↗
PubMedDate not supplied

Case report. Antenatal diagnosis of chorioangioma of the placenta: MR features.

We report a case of chorioangioma of the placenta, in which MR findings were useful in establishing the antenatal diagnosis. Polyhydramnios and a placental tumor that was 5 cm in size were visualized. The tumor had relatively high signal intensities on proton density imaging and T2-weighted imaging and showed partially high intensity signal rims on T1-weighted imaging, especially when using a breath-holding technique. Magnetic resonance imaging has an important role in detection and diagnosis of these lesions, particularly the larger tumors, so that appropriate steps can be taken to deal with the complications that may accompany this tumor.

Adult↗
PubMedDate not supplied

Learning proper nouns and common nouns without clues from syntax.

Syntax has been noted to play an important role in word learning in English; it distinguishes the fundamental conceptual difference between individuals (coded as proper nouns), nonindividuals (coded as mass nouns), and classes of individuals (coded as count nouns). The Japanese language does not have grammatical markers flagging the distinctions between count nouns and mass nouns, between proper nouns and common nouns, or between singulars and plurals. How Japanese 2- and 4-year-olds assign meaning to novel nouns associated with familiar and unfamiliar animals and inanimate objects was studied in the research reported here. When a novel label was given to an unfamiliar object, children assumed it to be a name for a basic-level object category whether the referent was an animal or an inanimate object. If the named object already had an established name, and if the object was an inanimate object, the children mapped the noun to a subordinate category. When the named object was an animal, however, they tended to interpret the label as a proper name. These results demonstrated that in the absence of useful information from syntax, 2-year-old Japanese children are able to fast map a noun to its meaning by elegantly coordinating word-learning biases and other available sources of information.

Child, Preschool↗
PubMedDate not supplied

The interferon-alpha 2b gene in Japanese patients with chronic viral hepatitis who developed antibodies after treatment with recombinant interferon-alpha 2a.

DNA was extracted from leucocytes of 23 Japanese patients with chronic viral hepatitis who received treatment with recombinant interferon-alpha 2a (IFN-alpha 2a) and nine healthy controls, as well as eight human cell lines of Caucasian or African origin. A part of the gene encoding IFN-alpha 2 was amplified by polymerase chain reaction and the sequence of nucleotides 1-231 was determined. Interferon-alpha 2a, -alpha 2b and -alpha 2c genes were tested for in five clones each from a patient or control, or a cell line, based on adenine or guanine at nucleotide positions 68 and 101. The IFN-alpha 2b gene was detected in all 160 clones from 23 Japanese patients and nine controls, but the IFN-alpha 2a or -alpha 2c gene was not found in any. Of five cell lines derived from Caucasians, four exhibited only the IFN-alpha 2b gene, while the remaining one exhibited both IFN-alpha 2a and -alpha 2b genes. Of three cell lines derived from Africans, one each showed only the IFN-alpha 2b or -alpha 2c gene, and the remaining one both IFN-alpha 2b and -alpha 2c genes. The 23 patients with the IFN-alpha 2b gene and chronic viral hepatitis included 10 who developed antibodies against IFN after treatment with recombinant IFN-alpha 2a. These results indicated a distinct geographical distribution of the three IFN-alpha 2 genes, and suggested the use of a recombinant IFN-alpha 2 preparation in agreement with the IFN-alpha 2 gene possessed by the recipient to avoid antibody responses.

Amino Acid Sequence↗
PubMedDate not supplied

Small-cell carcinoma of the uterine cervix: a clinicopathologic study of 11 cases.

We report the clinical profiles and immunohistochemical features of small-cell carcinoma of the uterine cervix. Eleven cases that we have encountered at the Department of Gynecology, Kitasato University Hospital, between 1971 and 2003 are presented. Of 1370 invasive carcinomas of the uterine cervix, the incidence of small-cell carcinoma was 0.8%. Patient ages ranged between 32 and 65 years, with a mean age of 46.3 years. The clinical stages at diagnosis were Ib in four patients, IIb in three, IIIb in three, and IVb in one. All patients presented with abnormal vaginal bleeding. Two patients who are alive with no evidence of disease for 12 years and 3 years 6 months, while eight patients died of primary carcinoma between 4 and 25 months after treatment. Histopathologic findings showed solid nests with marked peripheral palisading pattern and rosette formation. Small tumor cells with scant cytoplasm demonstrated a very high nuclear/cytoplasm ratio and indistinct cell borders. The nuclei were round to oval and demonstrated increased but fine granular chromatin. Nucleoli were indistinct in all cases. Immunohistochemical findings were positive in 81.8% each for neuron-specific enolase and protein gene product 9.5, 72.7% for synaptophysin, 63.6% for chromogranin A, and 54.5% for neural cell adhesion molecule. All specimens were positive for at least one of the above. In conclusion, small-cell carcinoma of the uterine cervix revealed poor prognosis. Making an accurate diagnosis of small-cell carcinoma before performing treatment is of great significance but often difficult. Immunohistochemical analysis using several kinds of neuroendocrine markers is helpful in establishing the correct diagnosis in addition to focusing on characteristic histo- and cytopathologic features.

Adult↗
PubMedDate not supplied

Significance of p27 as a predicting marker for medroxyprogesterone acetate therapy against endometrial endometrioid adenocarcinoma.

We reported that p27 induced by medroxyprogesterone acetate (MPA) may be involved in the progestin-induced growth suppression of human endometrial adenocarcinoma cells. This study aimed at investigating whether p27 expression could be a predicting marker to evaluate the effectiveness of MPA therapy. The clinical responses of 15 patients with endometrial carcinoma treated with MPA were examined. p27 expression was evaluated by immunohistochemical staining. Percentage of positive nuclear staining was expressed as a strongly positive (SP) labeling index (LI). Before MPA treatment, SP LIs in the effective and noneffective groups were 22.6 +/- 14.3% and 9.1 +/- 9.2%. At 1-6 weeks in the MPA treatment, SP LIs increased in both groups and were significantly higher than those before the therapy. At 7-12 weeks, SP LIs in both groups decreased to the level of pretherapy. At 13-18 weeks, SP LIs in the effective group were 14.9 +/- 5.7%, whereas in the noneffective group, 1.1 +/- 2.0%. The former was significantly higher than the latter. p27 expression could predict the effectiveness of MPA treatment for endometrial carcinoma at an early stage of the 4-month period in MPA therapy and could be a useful predicting marker for MPA.

Adult↗
PubMedDate not supplied

Cellular localization of aquaporin 7 in the rat kidney.

The cDNA for the seventh mammalian aquaporin (AQP7) was isolated from rat testis, and its expression was demonstrated at the tail of late spermatids [Ishibashi et al: J Biol Chem 1997;272:20782-20786]. AQP7 is also expressed in the kidney. The localization of AQP7 in the kidney is unknown. We examined the cellular localization of AQP7 in the kidney with Northern blot, reverse transcribed PCR, Western blot and immunohistochemistry in the rat kidney. In Northern blot, AQP7 was expressed in the cortex and the outer medulla but absent in the inner medulla of the kidney. Reverse transcribed PCR of rat nephron segments revealed the selective expression of AQP7 at the proximal straight tubules (PST). Western blot of the membrane fraction of outer medulla revealed a single band of approximately 33 kDa. Immunohistochemistry of the rat kidney showed the selective expression of AQP7 at the brush border membranes of PST (S3 segment). AQP7 is now shown to be localized selectively at the brush border membranes of PST in the rat kidney. The result suggests that AQP7 may function as a pathway for transcellular water transport in PST in concert with more widely expressed AQP1 in proximal tubules. Alternatively, as AQP7 transports urea as well as water, AQP7 may function as a passive urea secretory pathway in this segment and may play a role in the formation and/or maintenance of the medullary urea concentration gradient.

Animals↗
PubMedDate not supplied

Expression and inducibility of cytochrome P450 IIIA family within intrasplenically transplanted fetal hepatocytes.

With the development of transplantation of hepatocytes into the spleen, interest has focused on the metabolic changes associated with hepatocyte proliferation. As these changes are important for drug metabolism in hepatocytes, we examined the expression and inducibility of the cytochrome P450 IIIA family within transplanted hepatocytes. Fetal hepatocytes were harvested at 20 days of gestation from spontaneously hypertensive rats (SHRs) and transplanted into recipient adult SHR spleens. Microscopic examination of the recipient spleens 4 and 10 wk after transplantation revealed masses of hepatocytes with cord-like structures in the red pulp. Proliferating hepatocytes were detected with a bromodeoxyuridine (BrdU) immunohistochemical stain. Immunochemical studies detected cytochromes (cytos) P450 p and P450 HLp in fetal hepatocytes before transplantation without prior induction. And although these cytos were not detected by 10 wk after transplantation, they were induced with dexamethasone. These results demonstrated that fetal hepatocytes can be transplanted successfully into recipient spleens and suggested that fetal hepatocytes grow in the spleen, similar to the adult hepatocyte response.

Animals↗