Biomedical subjects

K Yoshimura

Publications and source records attributed to K Yoshimura.

At least 55 records · Page 3Linked to original sources

PubMed1991

Expression of the cystic fibrosis transmembrane conductance regulator gene in cells of non-epithelial origin.

Consistent with the fact that the clinical disorder cystic fibrosis (CF) is manifested on epithelial surfaces, active transcription of the CF transmembrane conductance regulator (CFTR) gene and CFTR mRNA transcripts are detectable in a variety of epithelial cells, suggesting CFTR gene expression might be epithelial cell-specific. However, analysis of the CFTR gene promoter suggests it is a housekeeping gene, implying more widespread expression than only in epithelial cells. To evaluate the latter hypothesis, various human cells of non-epithelial origin, including lung fibroblasts, U-937 histiocytic lymphoma cells, K-562 erythroleukemia cells, HL-60 promyelocytic leukemia cells as well as freshly isolated blood lymphocytes, neutrophils, monocytes, and alveolar macrophages were examined for CFTR gene expression. Although Northern analysis failed to show CFTR mRNA transcripts in these cells, amplification of mRNA (after conversion to cDNA) by polymerase chain reaction combined with Southern analysis demonstrated the presence of CFTR mRNA transcripts at low levels in all cells evaluated except HL-60 cells. Comparative quantitative analysis showed fibroblasts contained 200-400 fold less CFTR mRNA transcripts than the T84 and HT-29 colon carcinoma epithelial cell lines, but had similar levels of CFTR transcripts to those of other epithelial cell lines. Nuclear transcription run-on analyses demonstrated very low level CFTR gene transcription in fibroblasts and U-937 cells, similar to that of other epithelial cells, but lower than the T84 and HT-29 colon carcinoma cell lines. Interestingly, while chromatin DNA of fibroblasts had no DNase I hypersensitivity sites in the 5' flanking region of the CFTR gene, HT-29 chromatin DNA exhibited four DNase I accessible sites in the same region, suggesting that these sites may be related to more active transcription of the CFTR gene in the intestinal epithelial cells than in fibroblasts.

Base Sequence↗

PubMed1991

Expression of the cystic fibrosis transmembrane conductance regulator gene in the respiratory tract of normal individuals and individuals with cystic fibrosis.

The most common mutation of the cystic fibrosis transmembrane conductance regulator gene, CFTR, associated with the clinical disorder cystic fibrosis (CF) is called "delta Phe508," a triple-base deletion resulting in loss of phenylalanine at residue 508 of the predicted 1480-amino acid CFTR protein. In the context that the lung is the major site of morbidity and mortality in CF, we evaluated airway epithelial cells for CFTR mRNA transcripts in normal individuals, normal-delta Phe508 heterozygotes, and delta Phe508 homozygotes to determine if the normal and delta Phe508 CFTR alleles are expressed in the respiratory epithelium, to what extent they are expressed, and whether there are relative differences in the expression of the normal and abnormal alleles at the mRNA level. Respiratory tract epithelial cells recovered by fiberoptic bronchoscopy with a cytology brush demonstrated CFTR mRNA transcripts with sequences appropriately reflecting the normal and delta Phe508 CFTR alleles of the various study groups. CFTR gene expression quantified by limited polymerase chain reaction amplification showed that in normal individuals, CFTR mRNA transcripts are expressed in nasal, tracheal, and bronchial epithelial cells at approximately 1-2 copies per cell, more than 100-fold greater than in pharyngeal epithelium. Importantly, allele-specific hybridization studies demonstrated that the normal and delta Phe508 CFTR alleles are expressed in the respiratory epithelium in similar amounts.

Base Sequence↗

PubMed1991

Down-regulation of cystic fibrosis gene mRNA transcript levels and induction of the cystic fibrosis chloride secretory phenotype in epithelial cells by phorbol ester.

To evaluate the hypothesis that phorbol myristate acetate (PMA) might modulate the expression of the cystic fibrosis (CF) gene in epithelial cells, we examined the effect of PMA on CF mRNA levels and regulation of Cl- secretion. Strikingly, PMA down-regulated CF mRNA transcript numbers in a dose- and time-dependent manner. Importantly, in parallel with the reduction of CF mRNA levels, PMA-treated cells were unable to up-regulate Cl- secretion in a normal fashion in response to forskolin, an effect which was also dose- and time-dependent. Thus, PMA is capable of modulating expression of the CF gene and induces T84 cells to adopt the "CF phenotype" in regard to regulation of Cl- ion transport.

Blotting, Northern↗

PubMed1991

The cystic fibrosis gene has a "housekeeping"-type promoter and is expressed at low levels in cells of epithelial origin.

Evaluation of the expression of the cystic fibrosis (CF) gene in human epithelial cell lines demonstrated active, but low level, transcription of the gene. Analysis of 3.8 kilobases of genomic sequences 5' to exon 1 of the CF gene demonstrated no TATA promoter element, but a high G + C content, multiple transcription start sites, and several potential Sp1 binding sites. Fragments of 5'-flanking sequences from 2.2 kilobases to as small as 102 base pairs 5' to the major transcription start site supported constitutive reporter gene expression in epithelial cells, but at low levels, and independent of the length of the 5' fragment. CF gene transcription was down-regulated by phorbol myristate acetate. Importantly, evaluation of freshly isolated normal human bronchial cells also demonstrated CF gene transcription at a relatively low rate. Together, these observations suggest that although the normal CF gene promoter has characteristics of a "housekeeping"-type gene, and the gene is expressed at low levels in cells of organs that manifest the clinical disorder "cystic fibrosis," its expression can be modulated transcriptionally, implying a possible therapeutic approach for the disease.

Base Sequence↗

PubMed1991

Adenovirus-mediated transfer of a recombinant alpha 1-antitrypsin gene to the lung epithelium in vivo.

The respiratory epithelium is a potential site for somatic gene therapy for the common hereditary disorders alpha 1-antitrypsin (alpha 1AT) deficiency and cystic fibrosis. A replication-deficient adenoviral vector (Ad-alpha 1AT) containing an adenovirus major late promoter and a recombinant human alpha 1AT gene was used to infect epithelial cells of the cotton rat respiratory tract in vitro and in vivo. Freshly isolated tracheobronchial epithelial cells infected with Ad-alpha 1AT contained human alpha 1AT messenger RNA transcripts and synthesized and secreted human alpha 1AT. After in vivo intratracheal administration of Ad-alpha 1AT to these rats, human alpha 1AT messenger RNA was observed in the respiratory epithelium, human alpha 1AT was synthesized and secreted by lung tissue, and human alpha 1AT was detected in the epithelial lining fluid for at least 1 week.

Adenoviridae↗

PubMed1991

Apodemus sylvaticus, a new host for Acanthocheilonema viteae (Nematoda: filarioidea).

Susceptibility of Apodemus sylvaticus and A. agrarius to infection with Acanthocheilonema viteae was compared with that of hamsters and jirds. Microfilaremia in A. sylvaticus was first noted on day 52 post-infection (p.i.) and lasted during the course of the study (up to day 150 p.i.). Maximum microfilaremic levels (female worm basis) of A. sylvaticus [mean +/- S.D. (n) = 690 +/- 1288(6)] were considerably higher than those of hamsters [16 +/- 18(6)] and jirds [51 +/- 25(5)]. Adult worm recovery in A. sylvaticus ranged from 2 to 40% of the number of infective larvae inoculated. Worm development in A. sylvaticus resembled that in hamsters and jirds. In contrast, microfilaremia was not detected in, nor adult worms recovered from A. agrarius throughout the study.

Animals↗

PubMed1991

Malignant schwannoma associated with xeroderma pigmentosum in a patient belonging to complementation group D.

A 43-year-old man with xeroderma pigmentosum, XP97TO, was allocated to complementation group D. He had had moderate photosensitivity at age 1 year and freckles by age 6 but no neurologic abnormalities. Nevertheless, his fibroblasts in culture had the XP-D phenotype. They showed a sevenfold hypersensitivity to killing by 254 nm ultraviolet radiation and a diminished level (29%) of unscheduled DNA synthesis. Phototesting revealed delayed maximum erythema at 72 hours after UVB exposure and a lowered minimal erythema dose. Lentigo maligna developed on the patient's face, and a rapidly growing malignant schwannoma was found on the left trigeminal nerve. This may be the first case of a peripheral nervous tissue neoplasm in xeroderma pigmentosum.

Adult↗

PubMed1991

Nuclear membrane antigen specific to nerve and muscle tissues.

A monoclonal antibody, 2F7, raised against a nuclear protein subfraction recognized the nuclear membrane of nervous and muscular tissues of guinea pig, rat and rabbit, but no other tissue was stained. In the nervous system, both neurons and glial cells were labelled. An electron microscopic immunohistochemical study demonstrated that 2F7 antibody labelled the inner surface of the nuclear membrane. Western blot analysis on the nuclear envelope fraction containing nuclear lamina revealed that this antibody reacted to two minor component proteins of 80 and 82KDa. These 2F7 antigens expressed preferentially in the nervous and muscular tissues were distinct from the major nuclear envelope proteins reported so far and might be related to neuronal or muscular tissue-specific functions.

Animals↗

PubMed1991

Detection of nephritis strain-associated streptokinase by monoclonal antibodies.

Monoclonal antibodies (MAbs) N-59 and RU-1 were produced by immunisation of mice with streptokinase secreted by Streptococcus group A, type 12, strain A374 isolated from a patient with post-streptococcal glomerulonephritis (PSGN) and were characterised by Western blot analysis. MAb N-59 recognised antigenic determinants shared by both nephritis strain-associated streptokinase (NSA-SKase) and streptokinase of Streptococcus group C (C-SKase); MAb RU-1 reacted only with NSA-SKase. All nephritis-associated group A streptococcal strains tested reacted with MAb N-59; 87.5% of these strains reacted with MAb RU-1. MAb N-59 reacted with SKase produced by group G streptococcal strains isolated from patients with PSGN, and MAb RU-1 recognised SKase in two out of three of these strains.

Animals↗

PubMed1991

Striae distensae after tension-requiring skin sutures.

Three cases of striae distensae which developed along suture scars after skin surgery were described. The production of striae should be taken into consideration in surgery of the skin, especially in young woman.

Adolescent↗

PubMed1991

Identification of contact allergens in C.I. Solvent Red 23 (commercial Sudan III) by chemical analysis and animal testing.

C.I. Solvent Red 23, commercial Sudan III, is widely used in cosmetic products. Chemical analyses and guinea pig sensitization tests were carried out to identify its contact allergens. In the Magnusson & Kligman guinea pig maximization test, C.I. Solvent Red 23 showed 20% positive reactions. By conducting chemical analyses with HPLC and GLC, 2-naphthol (82 ppm), azobenzene (48 ppm), Sudan I (570 ppm) and many unknown impurities, as well as the main constituent pigment Sudan III (87%), were found. The chemical structure of one unknown impurity was identified as an isomer of Sudan III. We found that purified Sudan III showed no positive reaction, while the isomer elicited 30% positive reactions, in the same guinea pig test. Furthermore, cross-sensitization with p-phenylenediamine was investigated using the guinea pig test. Animals sensitized with p-phenylenediamine also showed positive elicitation reactions with purified Sudan III. From these results, the contact allergenicity of C.I. Solvent Red 23 is considered to be due to impurities, including the isomer of Sudan III, 1-(o-phenylazophenylazo)-2-naphthol. Positive reactions to Sudan III previously demonstrated in hairdressers are due to cross-sensitivity with p-phenylenediamine.

Allergens↗

PubMed1991

Pulmonary vascular distensibility of arterial, middle, and venous regions in newborn lambs.

The pulmonary circulation in the adult is characterized by being relatively distensible, but whether the newborn lung shares this feature is less certain. We perfused isolated lungs treated with indomethacin from lambs of four ages (less than 1, 2-4, 12-14, and 30-32 days) to determine the effects of increasing left atrial pressure on the pulmonary vascular pressures measured by vascular inflow and outflow occlusion. An index of pulmonary vascular distensibility was assessed by comparing the slope of the pulmonary vascular pressure at the upstream end of a region as a function of the pressure at the downstream end of the region. A vascular distensibility index (VDI) of 1 indicates a rigid nondistensible system, whereas a VDI less than 1 indicates some degree of distensibility. During normoxia, lungs from all age groups were relatively indistensible as determined by VDI for the total vasculature (VDItotal) as well as for the different regions based on occlusion pressures (VDIarterial, VDImiddle, and VDIvenous). There were significant effects of age on the VDItotal, with decreases in the normoxic values occurring over the first 12-14 days of age, indicating an increase in pulmonary vascular distensibility. Only the VDIvenous was similarly affected by increasing neonatal age. Hypoxia significantly reduced the VDItotal in these same age groups. In addition, hypoxia, which increased the pressure gradients of the arterial and middle regions, significantly increased the VDIarterial in the youngest and oldest age groups but significantly decreased the VDImiddle at all ages by approximately 50%. In summary, we observed age-related changes in the vascular distensibility of the pulmonary circulation, with the VDItotal decreasing with increasing postnatal age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Expression of the secretory leukoprotease inhibitor gene in epithelial cells.

The secretory leukoprotease inhibitor (SLPI) gene codes for a 12-kD protein that within the lung protects the airway epithelium from neutrophil elastase. Screening of 228 alleles in 114 individuals for sequence differences by RNase protection of genomic DNA revealed no detectable polymorphisms in SLPI gene exons II-IV. SLPI gene expression in the lung was demonstrated by identifying SLPI mRNA transcripts in bronchial epithelial cells freshly isolated from normals. Cell lines derived from mucosal surfaces (HS-24 bronchial squamous cell carcinoma, HeLa cervical carcinoma) actively transcribe the SLPI gene and contain SLPI mRNA transcripts, while lung fibroblasts demonstrate no evidence of SLPI gene expression. SLPI mRNA transcripts appear to be relatively stable, with mRNA levels only mildly affected by inhibition of RNA synthesis. Chromatin DNA of HS-24 cells demonstrates two DNase I hypersensitivity sites within the 5' flanking region of exon I of the SLPI gene, whereas fibroblast chromatin has no DNase I accessible sites in the same region. Further analysis of the 5' flanking region demonstrated two contiguous transcription start sites, CAAT and TATA boxes, and several potential regions of known DNA binding proteins. Overall, the SLPI gene appears to be a relatively nonpolymorphic, stable gene that is constitutively expressed at specific tissue sites, but has the potential to be modulated at both the transcriptional and posttranscriptional levels.

Base Sequence↗

PubMed1991

Indomethacin prevents ventilation-induced decreases in pulmonary vascular resistance of the middle region in fetal lambs.

Previously, we report that the major site of pulmonary vascular resistance in fetal lambs occurred in the middle region defined by vascular occlusion, and that this region exhibited the greatest decrease upon ventilation with O2. To assess the relative individual contributions of ventilation and oxygenation to this decrease, we determined the distribution of pressures across the pulmonary circulation in isolated perfused lungs from 20 fetal lambs (131 - 137 d gestation) by inflow and outflow vascular occlusions. A membrane oxygenator was included in the extracorporeal circuit to control the PO2 at 4 kPa (30 torr) in the unventilated fetal lungs. Half of the fetal lungs were ventilated first without changing the initial gas tensions, and the others were oxygenated first by changing the initial gas tension to a hyperoxic mixture [PO2 = 26.6 kPa (200 torr)] without ventilation. Finally, both groups of lungs were ventilated and oxygenated. In addition, indomethacin was added to the perfusate (0.112 mM, or 40 micrograms/mL) in half of the preparations in each group to determine the effect of prostaglandins on the distribution of pressures during these conditions. The decrease in the total pulmonary vascular resistance with ventilation and/or oxygenation was primarily due to changes in the middle pressure gradient (delta Pm). In fetal lungs without indomethacin, ventilation without oxygenation reduced delta Pm from 6.1 +/- 0.8 to 2.5 +/- 1.0 kPa, or 74% of the total ventilation- and oxygenation-induced decrease in delta Pm (final value = 1.2 +/- 0.6 kPa).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Evidence for an inequality in the forces that generate principal and reverse bends in sperm flagella.

The response of the mechanism initiating flagellar bends to imposed mechanical transients has been studied by holding the head of a sea urchin sperm in the tip of a sinusoidally vibrating micropipet and then displacing the micropipet laterally at a speed of up to 1.15 micron ms-1 for 1.5 beat cycle, without vibration, before resuming sinusoidal vibration with the initial phase, frequency and amplitude at the new location of the pipet. This transient displacement of the micropipet delays the initiation of the bend that was due to initiate 0.5 beat cycle after onset of the displacement. The amount of this delay increases with the speed of the displacement, for speeds up to 1 micron ms-1. Analysis of the flagellar waveforms during the transient showed that with imposed displacements at speeds of equal magnitude, the initiation of a principal bend was delayed to a longer extent than that of a reverse bend. At a micropipet speed of 0.75 micron ms-1, there was an average delay of 0.21 beat cycle in the initiation time of a principal bend as compared to a delay of only about 0.04 beat cycle in the initiation time of a reverse bend during displacements in the opposite direction. For both principal and reverse bends, the second bend due to initiate during the transient displacement initiated in most of the cases with no delay, regardless of the micropipet speed. Our results suggest that the force generated by microtubule sliding to initiated a new reverse bend is greater than that generated to initiate a principal bend.

Animals↗

PubMed1991

Dynamic changes in the rate of amylase release induced by various secretagogues examined in isolated rat parotid cells by using column perifusion.

Isolated parotid acinar cells were perifused in small columns by embedding them in Bio-Gel P-2 beads as an inert supporting matrix, and the effect of carbamylcholine, substance P, and isoproterenol on the rate of amylase release was examined by measuring amylase activity in the effluent. Amylase release by continuous stimulation with carbamylcholine and substance P was biphasic. They caused a rapid and large increase in the rate of amylase release that reached maximum 30 to 60s after the onset of stimulation, followed by a rapid decline to a lower sustained level that was maintained as long as the agonists were present. The rapid decline in the rate of amylase release was due to rapid development of refractoriness. Repeated 1 min pulse stimulation with these secretagogues showed that recovery from refractoriness was also rapid in onset, and 1 min of washout was sufficient to cause significant recovery from refractoriness for both carbamylcholine and substance P. Recovery, however, was not complete after 10 min of washout. Amylase release by continuous stimulation with isoproterenol, on the other hand, developed more slowly with the peak rate being attained at about 6 min after the onset of stimulation. Refractoriness was not observed in the effect of isoproterenol. The maximum effect in the rate of amylase release attained by carbamylcholine or substance P was higher than that by isoproterenol. These results suggest that the apparent small effect of carbamylcholine and substance P on amylase release reported earlier by using batch systems is probably due to the rapid development of refractoriness to these secretagogues, but not to isoproterenol.

Amylases↗

PubMed1991

[A case of pituitary adenoma and hyperplasia with primary hypothyroidism].

A 23 year-old woman was admitted to our hospital, complaining of sterility and obesity. Her serum TSH and Prolactin were abnormally high, and her serum T3, T4 were low. Contrast-enhanced computerized tomographic (CT) scan revealed a round mass in the sella and suprasellar region. A transsphenoidal operation was then performed. The intrasellar mass was composed of a soft liquid-like part and a solid part. Only the soft liquid-like part of the mass was removed. Histological examination showed the typical appearance of chromophobe adenoma, Reticulin stain of the specimen revealed no reticular network. The remnant of the mass was considered to be hyperplasia because the size of the mass decreased on serial CT scan after thyroid hormonal replacement. Sometimes it may be difficult to distinguish between hyperplasia and adenoma. The application of reticulin stains is considered to be useful for differentiation between hyperplasia and adenoma.

Adenoma↗

PubMed1991

[The fate of patients with intermittent claudication--comparison of surgical and non-surgical treatment].

The purpose of this study was to determine the operative indication for patients with intermittent claudication because of arteriosclerosis obliterans, and to compare the late result of the surgical treatment group (130 cases, 175 limbs) with that of the non-surgical treatment group (27 cases, 31 limbs). There were 3 operative deaths and 21 late deaths in the surgical group, and 11 late deaths in the non-surgical group. The number one cause of death was heart failure, including ischemic heart disease, in both groups. The 5-year cumulative patency rate was 92.5% in the aorto-iliac, 70.6% in the femoro-distal and 82.0% in the aorto-femoro-distal arterial reconstructions. Long term symptom free rates of the surgical group and the non-surgical group, except fatal cases, were 87.2% and 25.0% in the aorto-iliac, 57.7% and 25.0% in the femoro-distal, 86.7% and 0% in the aorto-femoro-distal arterial regions, respectively. Late result of intermittent claudication in the surgical group was better than that in the non-surgical group. We conclude that intermittent claudication should be considered to be the indication for surgery, except for the cases with high risk diseases or malignant diseases.

Female↗