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Biomedical subjects

Y Kitajima

Publications and source records attributed to Y Kitajima.

At least 73 records · Page 4Linked to original sources
PubMed1999

The effects of growth hormone on corpus luteum of superovulated rats.

In general, growth hormone acts as a factor promoting cell proliferation in the positive direction and suppresses apoptosis. No report has described growth hormone (GH)-induced structural luteolysis. The present studies showed that GH induced structural luteolysis in rats after the induction of functional luteolysis by treatment with bromocriptine, and that apoptotic cells were present among luteal cells during structural luteolysis as shown by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. Zymography showed that the activity of matrix metalloproteinase (MMP)-2 increased during GH-induced structural luteolysis. The expression of c-myc protein of luteal cells was significantly decreased, but proliferating cell nuclear antigens (PCNA) were conversely increased during structural luteolysis, as shown by Western blot analysis. We propose that an excessive increase in PCNA and a marked decrease in c-myc protein of luteal cells lead to a disorder in the signals concerned with DNA synthesis, causing mitotic catastrophe and inducing apoptosis in luteal cells, and that structural luteolysis may be triggered. GH-induced apoptosis in structural luteolysis therefore highly depends on the cell cycle. There are thought to be two mechanisms of GH-induced structural luteolysis. One is apoptosis, and the other is destruction of extracellular matrix by MMP.

20-alpha-Dihydroprogesterone↗
PubMed1999

Gonadotropin-releasing hormone agonist has the ability to induce increased matrix metalloproteinase (MMP)-2 and membrane type 1-MMP expression in corpora lutea, and structural luteolysis in rats.

Gonadotropin-releasing hormone (GnRH) and its agonist analog (GnRHa) are well known to have luteolytic effects. We previously reported that prolactin (PRL) stimulated matrix metalloproteinase (MMP)-2 activity to degrade collagen type IV as a mechanism of structural luteolysis. The effects of GnRHa treatment on developed corpora lutea are unknown. In this study we assessed the effect of GnRH on MMP expression and induction of structural involution of developed corpora lutea of superovulated rats using GnRHa. Pregnant mare serum gonadotropin-human chorionic gonadotropin (hCG)-synchronized ovulation and luteinization were induced in immature female rats, followed by daily treatment with GnRHa from 5 days after hCG treatment. GnRHa-induced involution of corpora lutea was evident 3 days after the treatment, as shown by their markedly smaller size (60% of the control weight). Nine days after hCG injection, serum progesterone and 20alpha-dihydroprogesterone concentrations were as low as those associated with structural luteolysis. These findings revealed that GnRHa has the ability to induce structural luteolysis in superovulated rats in the same way that PRL does. To gain information on mechanisms of luteal involution induced by GnRHa, we performed gelatin zymography. This showed a significant increase in the active form of MMP-2 in the luteal extract of GnRHa-treated rats (more than twofold that of the control). Activation of pro-MMP-2 by membrane type-MMP (MT-MMP) is reported to be a rate-limiting step for catalytic function. Another function of MT-MMP is to degrade collagen types I and III. The plasma membrane fraction of corpora lutea of GnRHa-treated rats activated pro-MMP-2 of fetal calf serum, resulting in a marked shift of the 68-kDa band to the 62-kDa band in the zymogram. A Northern hybridization study also revealed simultaneous significant increases in expression of MMP-2 mRNA and MT1-MMP mRNA in corpora lutea of GnRHa-treated rats (more than threefold the control level). In summary, hormonal and histological features of corpora lutea of GnRHa-treated superovulated rats correspond to those of structural luteolysis. GnRHa stimulated the expression of MMP-2 and MT1-MMP in developed corpora lutea associated with involution. These findings support the conclusion that MMP-2, activated by MT1-MMP, and MT1-MMP itself, remodel the extracellular matrix during structural luteolysis induced by GnRHa.

Analysis of Variance↗
PubMed1999

[Successful combination chemotherapy for a case of small cell carcinoma of the rectum with multiple liver metastasis].

A 69-year-old-man with small cell carcinoma of the rectum and multiple liver metastases was admitted in December 1996. Poorly differentiated adenocarcinoma was preoperatively diagnosed in a biopsy specimen from the rectum. Chemolipiodolization using 50 mg DXR and 6 ml lipiodol was performed for the multiple liver metastases. Ten days later, he underwent rectal amputation including lymph node dissection combined with the implantation of reservoir for hepatic arterial infusion chemotherapy. After operation 5-FU (500 mg, days 1-5) and CDDP (10 mg, days 1-5) were injected for 3 weeks through hepatic arterial route. The metastatic lesions in the liver represented a good response to the chemolipiodolization, though the metastatic tumor in the liver S4 region did not disappear on CT scan. The histological diagnosis of the resected rectum revealed small cell carcinoma so we attempted additional chemotherapy according to the regimen for treatment of small cell lung cancer. ETP + CDDP therapy was performed, in which ETP (100 mg, days 1-3) and CDDP (80 mg, day 1) were intraarterially infused. After three courses of this therapy, he achieved a complete response (CR) for the liver metastasis. Two courses of ETP + CDDP therapy were additionally performed in the outpatient department, and treatment is currently continued by oral administration of ETP (75 mg/day). He has been free of the disease for 16 months with few side effects. The combination therapy of chemolipiodolization and hepatic arterial infusion chemotherapy with ETP and CDDP may assure a good prognosis for multiple liver metastases of small cell rectal cancer.

Aged↗
PubMed1999

Molecular cloning of a second phospholipase B gene, caPLB2 from Candida albicans.

Accumulating evidence suggests that phospholipase B, secreted by pathogenic fungi such as Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, functions as one of the virulence factors. In the present study, we have attempted to clone phospholipase B gene from C. albicans. By RT-PCR analysis with degenerate primers based on conserved regions of phospholipase B from Saccharomyces cerevisiae, Penicillium notatum and Torulaspora delbrueckii two similar but different cDNA fragments were obtained. One corresponded to the partial sequence of caPLB1, recently cloned phospholipase B gene from C. albicans by a different approach (Leidich et al.: J Biol Chem 1998; 273: 26078-86). The other fragments contained sequences similar to the corresponding sequences of phospholipase B from other fungi. The presence of two related genes was confirmed by Southern and Northern blot analyses. The full length of the second C. albicans phospholipase B gene (caPLB2) encoded a putative protein with 608 amino acids and contained a potential signal peptide sequence and a putative catalytic region, which are found in phospholipase B from other fungi. Consistent with the findings of caPLB1, caPLB2 also lacks a cluster of hydrophobic amino acids at the COOH-terminal, which may function as a signal of glycosylphosphatidylinositol anchor.

Amino Acid Sequence↗
PubMed1999

Partial amino acid sequence of an amyloid fibril protein from unusual cutaneous cystic lesions in myeloma-associated amyloidosis.

Although common cutaneous lesions in myeloma-associated systemic amyloidosis are petechiae, purpura, ecchymoses, plaques, waxy, translucent or purpuric papules or nodules, we encountered an unusual case of myeloma-associated amyloidosis with multiple cystic nodules. We isolated amyloid substance from the cutaneous cystic nodules of this patient and characterized it ultrastructurally, immunologically, and biochemically. Electron microscopy demonstrated that amyloid substances isolated by distilled water were principally straight and non-branching fibrils with a diameter of 8 to 10 nm, which was morphologically similar to amyloid fibrils. SDS-PAGE showed that these fibrils consisted of the 20 kDa and 29 kDa peptides, which reacted with the antibody to kappa light chain of immunoglobulin by immunoblot study. Partial amino acid sequence of N-terminal residues of this 20 kDa peptide showed a homology to kappa immunoglobulin light chain of variable subgroup I. These results suggest that amyloid fibrils in this unusual case with cutaneous cystic nodules may be derived from kappa I light chain of immunoglobulin.

Aged↗
PubMed1998

Molecular cloning of a gene encoding phospholipase D from the pathogenic and dimorphic fungus, Candida albicans.

A phospholipase D gene (CaPLD) has been cloned from the Candida albicans genomic DNA library. The CaPLD is a member of a highly conserved gene family of PLD and has the highest homology to Saccharomyces cerevisiae PLD (SPO14) with an overall homology of 42%. Phylogenetic analysis indicated that fungus PLDs including CaPLD composed one of the three clusters of PLD genes.

Amino Acid Sequence↗
PubMed1998

Performance of the YB(66) soft X-ray monochromator crystal at the wiggler beamline of the UVSOR facility.

Soft X-ray spectra have been measured using a pair of YB(66)(400) monochromator crystals at the double-crystal monochromator beamline BL7A of the UVSOR facility, where the wiggler radiation has a magnetic field of 4 T. Deformation of the YB(66) crystal due to heat load from the synchrotron radiation is almost negligible. The photon flux is about 10(8) photons s(-1) (100 mA)(-1) in the energy region 1.2-2 keV and the energy resolution is 0.7 +/- 0.1 eV around hnu = 1.5 keV. These results show that the YB(66) crystal is suitable for use as a monochromator crystal. Its application to soft X-ray spectroscopy is discussed.

Journal Article↗
PubMed1998

Spectrometer for polarized soft X-ray Raman scattering.

An experimental system for polarized soft X-ray Raman scattering spectroscopy has been constructed. The soft X-ray spectrometer is based on the Rowland circle geometry with a holographic spherical grating. Three types of gratings are used to cover the energy range from 18 eV to 1200 eV. According to a ray-trace simulation, the resolution is expected to be 200 meV at 700 eV by using a 10 micro m slit width. The polarized and depolarized soft X-ray Raman scattering spectra can be measured by rotating the soft X-ray spectrometer around the axis of the incident beam. Preliminary measurements of polarized and depolarized spectra were accomplished at undulator beamline BL-2C of the Photon Factory.

Journal Article↗
PubMed1998

A soft X-ray (80-1500 eV) grazing-incidence monochromator with varied-line-spacing plane gratings at PF-BL-11A.

The design and performance of a new soft X-ray beamline BL-11A at the Photon Factory (PF) are presented. A Hettrick-type grazing-incidence monochromator equipped with three varied-line-spacing plane gratings was designed and constructed at a bending-magnet source of the PF 2.5 GeV storage ring. An 800 lines mm(-1) laminar grating produced by aspheric-wavefront holographic recording optics, as well as a mechanically ruled blazed one, were tested. A resolving power of more than 4500 was achieved at 400 eV with either grating, and approximately 10(10) photons s(-1) are available at a resolving power of 2000. High photon flux enables low-concentration samples, such as surface adsorbates, to be studied. A simple scanning mechanism for a wide energy range is quite useful for EXAFS measurements on light elements such as C, N and O.

Journal Article↗
PubMed1998

Cleavage of BP180, a 180-kDa bullous pemphigoid antigen, yields a 120-kDa collagenous extracellular polypeptide.

The hemidesmosome (HD) is a cell-to-substrate adhesion apparatus found in stratified and complex epithelia. One of the putative cell-matrix adhesion molecules present in the HD is the 180-kDa bullous pemphigoid antigen (BP180), also termed type XVII collagen. In our previous study, using a monoclonal antibody (mAb) 1337, we have detected a 120-kDa collagenase-sensitive polypeptide in the HD fraction (Uematsu, J. and Owaribe, K. (1993) Cell Struct. Funct. 18, 588 (abstr.)). The present study was undertaken to assess the relation of the 120-kDa polypeptide to this BP180. Immunofluorescence microscopy of bovine skin revealed the basement membrane zone of skin to be stained clearly with mAb 1337, whereas the lateral surfaces of basal cells, which were decorated by typical antibodies against BP180, were not. The antibody did not detect HDs in cultured cells but rather in the culture medium. These results indicate a localization of mAb 1337 antigen distinct from BP180. However, the same polypeptide was also recognized by monoclonal antibodies to the extracellular but not the cytoplasmic part of BP180, and found to react with a polyclonal antibody against the non-collagenous 16A domain of BP180. Therefore, the polypeptide was identified as an extracellular fragment of BP180. mAb 1337 immunoprecipitated the 120-kDa fragment from the medium, but not the 180-kDa molecule of BP180 extracted from cultured cells, indicating that the antibody specifically recognizes the fragment. The mAb 1337 apparently recognizes a unique epitope that is exposed or formed by the cleavage. Hence, the staining pattern observed for bovine skin demonstrated the presence of the 120-kDa extracellular fragment. Rotary shadow electron microscopy of affinity-purified 120-kDa fragments demonstrated that they have the unique molecular shape consisting of a central rod and a flexible tail, without the globular head that is present in the BP180 molecule. From these results, we conclude that mAb 1337 shows unique epitope specificity, recognizing only the 120-kDa extracellular fragment of BP180, which is constitutively cleaved on the cell surface as a 120-kDa fragment both in in vivo and in vitro.

Animals↗
PubMed1998

The effect of electrical acupuncture-stimulation therapy using thermography and plasma endothelin (ET-1) levels in patients with progressive systemic sclerosis (PSS).

In all 11 patients with progressive systemic sclerosis (PSS; Barnett type I, 2; type II, 5; type III, 4 cases; male 1; female 10 cases; 45.2 +/- 10.2 years-old), 6 cases of scleroderma spectrum disorders (SSD, male 1; female 5 cases; 51.2 +/- 13.2 years-old) and 7 healthy controls (HC, male 1; female 6 cases; 43.1 +/- 8.4 years-old) were entered to be examined. The plasma endothelin-1 (ET-1) levels of PSS, SSD and HC were 1.98 +/- 0.69, 1.76 +/- 0.39 and 1.15 +/- 0.38 pg/ml, respectively. After the stimulation with the low frequency electrical current, electrical acupuncture, for unilateral side of hand/arm (30 min), the plasma ET-1 levels decreased in 10 cases of PSS treated (1.61 +/- 0.45 pg/ml), but no change of plasma serotonin levels. In 4 of 6 cases of SSD, plasma ET-1 levels increased (2.06 +/- 0.39 pg/ml), however, nitrate levels increased and serotonin decreased in 3 of 5 cases of SSD. In 6 cases of HC treated with the electrical acupuncture, the plasma ET-1 levels increased (1.72 +/- 0.58 pg/ml). Thermographically, 9 of 11 cases of PSS and 5 of 6 cases of SSD showed temporally temperature-elevation of hand/fingers not only in treated sides, but also in non treated sides, although none of 7 HC showed temperature-elevation of hands/fingers. The decrease in plasma ET-1 levels due to the electrical acupuncture was thought to induce the vasodilatation and elevate the surface temperature in patients with PSS. These results will provide an excellent basis to study the efficacy of electrical acupunctural stimulation.

Acupuncture Therapy↗
PubMed1998

Decreased phospholipase D (PLD) activity in ceramide-induced apoptosis of human keratinocyte cell line HaCaT.

Ceramide is recognized as an intracellular lipid second messenger, which induces various kinds of cell function including apoptosis. To evaluate the competence of ceramide on the keratinocyte apoptosis, we examined effects of a cell-permeable ceramide, N-acetylsphingosine (C2-ceramide), on a human keratinocyte cell line, HaCaT. C2-ceramide induced a distinct apoptosis in HaCaT cells in a time-dependent manner, as inferred by morphologic hallmarks of apoptosis such as bleb formation, cell body shrinkage, nuclear chromatin condensation, and internucleosomal DNA fragmentation. In sharp contrast, an inactive C2-ceramide, dihydroC2-ceramide, which lacks the 4-5trans double bond, failed to induce the apoptosis. The apoptotic HaCaT cells induced by C2-ceramide showed a significant suppression of phospholipase D (PLD) activity, regardless of the presence or absence of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS). This indicates that C2-ceramide inhibits both GTPgammaS dependent and GTPgammaS independent PLD. The membrane associated GTPgammaS dependent PLD activity was stimulated by recombinant adenosine diphosphate-ribosylation factor. The adenosine diphosphate-ribosylation factor dependent and independent PLD activities were inhibited by C2-ceramide in a concentration dependent manner, but not by the inactive C2-ceramide. The concentration of C2-ceramide to inhibit the membrane associated PLD activity was comparable with that required for apoptosis induction in HaCaT cells. It was thus suggested that downregulation of PLD activity may be involved in the mechanism underlying C2-ceramide induced keratinocyte apoptosis.

Apoptosis↗
PubMed1998

Internalization of the 180 kDa bullous pemphigoid antigen as immune complexes in basal keratinocytes: an important early event in blister formation in bullous pemphigoid.

We have previously shown that the 180 kDa bullous pemphigoid antigen (BPAG2) is distributed on the lateral-apical (as a pool) and ventral (as hemidesmosomes) cell membranes of monolayer cultured keratinocytes and that addition of IgG purified from bullous pemphigoid (BP) patients (BP-IgG) causes the internalization of immune complexes of BPAG2 and BP-IgG from the lateral-apical cell membrane. This internalization of BPAG2 is believed to inhibit the Ca2+ induced reformation of hemidesmosomes on the ventral cell membrane, possibly by inhibiting the supply of the antigen from the lateral-apical to the ventral membranes to form hemidesmosomes. The purpose of this paper is to examine, by using biopsy specimens from BP patients (12 cases), whether or not this internalization of BPAG2 is generated in situ. The fates of BPAG2, 230 kDa BPA (BPAG1) and bound BP-IgG were traced by immunofluorescence microscopy using monoclonal antibodies to BPAG1, BPAG2 and human IgG. In more than half of the lesional and perilesional biopsy specimens, internalization of BPAG2 into the basal cells was observed, while in normal skin BPAG2 was detected on the whole surface of the basal cells without its internalization. No internalization of BPAG1 was detected in BP and normal epidermis. These results suggest that binding of BP-IgG on the lateral-apical cell surface of basal cells causes internalization of BPAG2 in situ in the epidermis of BP patients similar to that seen in cultured cell systems, and that this internalization of immune complexes of BPAG2 and BP-IgG may play an important part in blister formation in BP.

Aged↗
PubMed1998

Precise ultrastructural localization of in vivo deposited IgG antibodies in fresh perilesional skin of patients with bullous pemphigoid.

Bullous pemphigoid (BP) is a blistering skin disease in which the patient develops autoantibodies to the epidermal basement membrane zone. Using postembedding immunogold electron microscopy, we previously demonstrated that autoantibodies against the 230-kDa BP antigen (BPAG1) bind to the intracellular hemidesmosomal component of normal skin, whereas those against the 180-kDa BP antigen (BPAG2) bind only along the plasma membrane of hemidesmosomes. The purpose of the present study was to elucidate the precise localization of the in vivo deposited IgG antibodies in fresh perilesional skin of patients with BP. Samples of fresh perilesional skin were obtained from three patients with BP whose sera reacted only with BPAG1, only with BPAG2, and with both BPAG1 and BPAG2 upon immunoblotting using epidermal extracts. Cryofixed and cryosubstituted skin samples were used as a substrate for on-surface immunolabelling. In all three cases, most of the gold particles were observed close to the plasma membrane of the basal keratinocytes. A quantitative analysis revealed that most (> 80%) of the in vivo deposited IgG antibodies in the three cases were localized within 10 nm inside to 50 nm outside of the cell membrane, with a single peak observed 0-10 nm outside of the cells (> 50%). This distribution corresponded to the location of BPAG2, but not to that of BPAG1. These findings suggest that most, if not all, of the in vivo deposited IgG antibodies in the perilesional skin of BP are directed against BPAG2, rather than against BPAG1, thus further supporting the crucial role of anti-BPAG2 autoantibody in the initial stage of blister formation in BP.

Autoantigens↗
PubMed1998

Pemphigus with features of both vulgaris and foliaceus variants, associated with antibodies to 160 and 130 kDa antigens.

We report an unusual variant of pemphigus in a 44-year-old man. He presented with scaly and crusted erosions associated with pruritic vesicles and erythema mainly on the chest, abdomen, back and face. Histology showed acantholysis with neutrophilic spongiosis in the granular layer and subcorneal region of the epidermis. Intercellular IgG in the epidermis was positive on direct immunofluorescence. Indirect immunofluorescence showed intercellular antibodies at a titre of 1 : 2 in the suprabasal epidermis. Circulating autoantibodies to 130 kDa and 160 kDa antigens were detected in the patient's serum by immunoblot analysis using epidermal extracts. These two antibodies eluted from individual nitrocellulose membranes reacted with the intercellular space in the epidermis on indirect immunofluorescence. This observation suggests that these antibodies correspond to desmogleins 3 and 1, respectively. The clinical symptoms almost completely disappeared after 28 days treatment with oral prednisolone (30 mg/day), leaving brown pigmented flecks on the lesional sites. These findings suggest that this patient's pemphigus has features of both the vulgaris and foliaceus variants, with antibodies against desmogleins 3 and 1.

Adult↗
PubMed1998

Effects of estradiol and an aromatase inhibitor on progesterone production in human cultured luteal cells.

The human corpus luteum produces both estradiol and progesterone. It is well known that there are both autocrine and paracrine systems for the regulation of the corpus luteum and that estradiol regulates the progesterone production of the corpora lutea of some other species. To assess the direct effects of estrogen on human luteal function, we performed cell culture experiments. A low concentration of estradiol, almost equal to the amount of estradiol produced by human cultured luteal cells, directly stimulated progesterone production. 4-Cyclohexylaniline, an aromatase inhibitor, significantly reduced both progesterone production and estradiol production. Levels of estradiol higher than the levels that cultured human luteal cells themselves produced significantly reduced basal progesterone production and also significantly reduced human chorionic gonadotropin (hCG), forskolin and dibutyryl-cyclic AMP-stimulated progesterone production. According to these data, high doses of estradiol produced a luteolytic action which widely inhibited the steroidogenesis process. In conclusion, our results indicated that estradiol in part regulates progesterone production physiologically and blocks progesterone production in a pharmacological or pathological state in the human corpus luteum.

Aniline Compounds↗