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Biomedical subjects

H Kaji

Publications and source records attributed to H Kaji.

At least 127 records · Page 7Linked to original sources
PubMed1995

Induction of single ovulation by sequential follicle-stimulating hormone and pulsatile gonadotropin-releasing hormone treatment.

OBJECTIVE: To induce single follicular ovulation by sequential treatment with FSH and pulsatile GnRH. DESIGN: Prospective study. PATIENTS: Eighteen hypogonadotropic anovulatory patients. INTERVENTIONS: In sequential treatment, daily FSH injection was switched to pulsatile GnRH administration (20 micrograms/120 minutes SC) when the follicle diameter reached 11 mm. In conventional FSH treatment, daily FSH injection was continued. In both cycles, hCG was given when the diameter of the dominant follicle reached 18 mm. MAIN OUTCOME MEASURES: Developed follicle numbers and serum FSH concentrations during treatment. RESULTS: Single follicular development was achieved in 80.0% of cycles by sequential treatment but in no cycle by conventional FSH treatment. The number of developed follicles was 1.26 +/- 0.55 (mean +/- SD) on sequential treatment and 3.94 +/- 1.48 on conventional FSH treatment. Preovulatory FSH level was significantly lower on sequential treatment than on conventional FSH treatment (5.26 +/- 1.80 versus 11.55 +/- 3.43 mIU/mL [conversion factor to SI unit, 1.00]). CONCLUSION: The sequential treatment achieved single follicular development without complications. The sequential FSH-pulsatile GnRH treatment may offer a better chance for development of a single dominant follicle and ovulation.

Adult↗
PubMed1995

Effect of retinoic acid on the proliferation and alkaline phosphatase activity of osteoblastic MC3T3-E1 cells by modulating the release of local regulators from monocytes.

There has been some evidence suggesting an important role of mononuclear cells at bone remodeling sites in the coupling of bone formation to bone resorption. Since cells of the monocyte-macrophage lineage produce important local regulators of bone remodeling, we examined effects of human monocytes-conditioned medium (CM) treated with retinoic acid on [3H] thymidine incorporation (TdR) and alkaline phosphatase (ALP) activity of osteoblastic MC3T3-E1 cells. Treatment of MC3T3-E1 cells with retinoic acid (10(-8) to 10(-6) M) caused an inhibition of TdR in a dose-dependent manner and an inhibition of ALP activity at 10(-6) M. Conditioned medium from monocytes untreated with retinoic acid caused a stimulation of TdR and an inhibition of ALP activity in these cells. In contrast, treatment of monocytes with retinoic acid (10(-8) or 10(-6) M) abolished both stimulation of DNA synthesis and inhibition of ALP activity induced by CM. The present study suggested that retinoic acid modulated osteoblast proliferation and ALP activity not only directly but also indirectly, presumably through modulating the release of local regulators as to bone remodeling from monocytes.

Alkaline Phosphatase↗
PubMed1995

Fasting increases the expression of basic fibroblast growth factor (FGF-2) messenger ribonucleic acid in rat hypothalamus.

Basic fibroblast growth factor (FGF-2) has been isolated from the brain, but the regulation of FGF-2 synthesis in the brain is not yet fully understood. Since exogenously administered FGF-2 has been reported to suppress food intake as well as the secretion of gastric acid and pepsin in rats, we examined the effect of fasting on FGF-2 mRNA levels in the hypothalamus and the cerebral cortex of male rats, using RNase protection assay. Fasting for 72 h resulted in an approximately 2-fold increase in FGF-2 mRNA level in the hypothalamus but did not affect FGF-2 mRNA level in the cerebral cortex significantly. These findings support the hypothesis that FGF-2 plays a significant role in regulation of hypothalamic function.

Adrenalectomy↗
PubMed1995

Antiviral action of oligodeoxyguanylic acids against human immunodeficiency virus type 1.

Deoxyguanylic acids, but not other deoxynucleotides, as short as 3- to 4-mer, were effective in preventing HIV-1-induced cytopathicity. In addition, they prevented giant cell formation of infected Sup-T1 cells, and p24 production in HIV-1 infected H9 cells. Phosphorylation at either the 5'- or 3'-end enhanced these activities. Furthermore, 5'-phosphorylated phosphorothioate tetradeoxyguanylic acid was effective in reducing HIV production in chronically infected cells (H9/IIIB). The search for the target steps of this compound revealed that it inhibits at least 3 steps in the life cycle of HIV: interaction with CD4 (measured by inhibitory effect on the syncytia formation between Sup-T1 and H9/IIIB cells), reverse transcriptase, and step(s) after integration. These results suggest that phosphorylated phosphorothioate tetradeoxyguanylic acid may be a novel candidate for a therapeutic agent of AIDS.

Antiviral Agents↗
PubMed1995

Significance of the highly conserved Gly-4 residue in human cystatin A.

The expression system for human recombinant cystatin A has already been established to be a fusion protein with porcine adenylate kinase in Escherichia coli [Kaji et al. (1990) Biol. Chem. Hoppe-Seyler 371, Suppl., 145-150]. After cyanogen bromide cleavage of the fused protein expressed in E. coli, the cystatin portion could be readily isolated. The inhibitory activity of the obtained variant (Cyst A (2-98)) was found to be almost identical with that of the wild type, and thereafter a mutation was introduced into this variant (Ctst A(2-98)), called the standard variant. To elucidate the role of the Gly-4 residue, which is completely conserved in all cystatin species, this residue was substituted with 17 other amino acids by means of cassette mutagenesis. Thus 17 variants (Cyst A(2-98)[G4X]) obtained were examined as to their inhibitory activity towards papain. As the side chain of the substituted amino acid residue became more bulky, the inhibitory activity of the variant markedly decreased. Variants whose side chains were bulkier than a Val residue showed almost no inhibitory effect towards papain. Consequently, it was deduced that the large side chain of a substituted amino acid may cause steric hindrance, which may be responsible for the decrease in inhibitory activity. Thus, we could conclude that the 4th (Gly) residue on cystatin A must be small, because amino acids which existed on the N-terminal side of this residue could interact with a papain molecule.

Amino Acid Sequence↗
PubMed1995

Human TRH receptor messenger ribonucleic acid levels in normal and adenomatous pituitary: analysis by the competitive reverse transcription polymerase chain reaction method.

OBJECTIVE: Little is known about the mechanism of diversity in in-vivo hormonal responsiveness to TRH in patients with functional pituitary adenomas. In order to clarify the relation between the responsiveness to TRH and TRH receptor messenger ribonucleic acid (mRNA) expression, we attempted to measure TRH receptor mRNA levels in human pituitary adenoma tissues by competitive reverse transcription polymerase chain reaction (RT-PCR) method. PATIENTS: Pituitary tissue samples were obtained at autopsy from 5 patients without pituitary disease. Pituitary adenoma tissue samples were obtained at surgery from 18 patients with pituitary adenoma (4 non-functioning, 8 prolactinoma, 4 acromegaly, 1 Cushing's disease and 1 FSH producing adenoma). METHODS: Partial TRH receptor cDNA from a human GH producing adenoma cDNA library was amplified by PCR under low stringency conditions using primers encoding the transmembrane domains III and VI of pituitary TRH receptor cDNA. The partial sequence of the amplified cDNA determined by a dideoxy-chain termination method was identical to the corresponding sequence of human TRH receptor cDNA. A competitor was generated by deleting the inner 111 bp from the amplified TRH receptor cDNA and subcloning. RNA extracted from human pituitary was reverse transcribed and co-amplified with competitor by PCR under higher stringency conditions. The TRH receptor mRNA levels, expressed as the relative intensity against the amplified levels of competitor, were compared among various pituitary tissues. RESULTS: The relative TRH receptor mRNA levels of pituitary tissues in patients without pituitary disease were detectable and variable (M +/- SD) (0.370 +/- 0.231, n = 5), and slightly but not significantly lower than those in patients with pituitary tumours (0.598 +/- 0.265, n = 18). In patients with prolactinoma, the relative levels of TRH receptor mRNA were quite variable (0.02-1.170, 0.604 +/- 0.358, n = 8) and not correlated with PRL responsiveness to TRH (responder 0.457; non-responder 0.340-0.950). In patients with acromegaly, TRH receptor mRNA was detectable not only in the paradoxical GH responder to TRH (0.718) but also in the non-responder (0.758 and 0.765). In one patient with Cushing's disease, a relatively low level of TRH receptor mRNA could be detected (0.415). In the patient with a FSH producing tumour whose plasma FSH did not respond to TRH, a small amount of TRH receptor mRNA was detectable (0.447). CONCLUSIONS: In patients with functioning pituitary adenomas, hormonal responsiveness to TRH in vivo might not be assessable by TRH receptor mRNA levels in the adenoma cells.

Adenoma↗
PubMed1995

Anti-human immunodeficiency virus (HIV) activities of halogenated gomisin J derivatives, new nonnucleoside inhibitors of HIV type 1 reverse transcriptase.

Halogenated gomisin J (a derivative of lignan compound), represented by the bromine derivative 1506 [(6R, 7S, S-biar)-4,9-dibromo-3,10-dihydroxy-1,2,11,12-tetramethoxy-6, 7-dimethyl-5,6,7,8- tetrahydrodibenzo[a,c]cyclo-octene], was found to be a potent inhibitor of the cytopathic effects of human immunodeficiency virus type 1 (HIV-1) on MT-4 human T cells (50% effective dose, 0.1 to 0.5 microM). Gomisin J derivatives were active in preventing p24 production from acutely HIV-1-infected H9 cells. The selective indices (toxic dose/effective dose) of these compounds were as high as > 300 in some systems. 1506 was active against 3'-azido-3'-deoxythymidine-resistant HIV-1 and acted synergistically with AZT and 2',3'-ddC. 1506 inhibited HIV-1 reverse transcriptase (RT) in vitro but not HIV-1 protease. From the time-of-addition experiment, 1506 was found to inhibit the early phase of the HIV life cycle. A 1506-resistant HIV mutant was selected and shown to possess a mutation within the RT-coding region (at position 188 [Tyr to Leu]). The mutant RT expressed in Escherichia coli was resistant to 1506 in the in vitro RT assay. Some of the HIV strains resistant to other nonnucleoside HIV-1 RT inhibitors were also resistant to 1506. Comparison of various gomisin J derivatives with gomisin J showed that iodine, bromine, and chlorine in the fourth and ninth positions increased RT inhibitory activity as well as cytoprotective activity.

Antiviral Agents↗
PubMed1995

In-vitro Biological Study to Evaluate the Toxic Potentials of Fibrous Materials.

The potential toxicities of fibrous materials were investigated by measuring the levels of cytokines as well as cytoplasmic and lysosomal enzymes released from alveolar macrophages (AMs) in vitro. Five man-made mineral fibers (ceramic, glass, potassium octatitanate, and two magnesium sulfate whiskers), as well as five natural mineral fibers (UICC chrysotile, crocidolite, amosite, anthophylite, and Turkish erionite) were tested. Basic fiber characteristics, including fiber size, surface area, number, and solubility, were also measured. Tumor necrosis factor (TNF) production, lactate dehydrogenase (LDH) and beta-glucuronidase (BGU) release from AMs exposed to potassium octatitanate, magnesium sulfate whiskers, and ceramic fiber correlated with pathologic changes in the lung according to inhalation studies. The solubility of the man-made mineral fibers also correlated with the half-life of clearance in an in-vivo study. The results suggest that measured values of TNF production, LDH and BGU release in vitro, and fiber solubility combined are a good indicator of the pathogenic potential of fibers in vivo.

Journal Article↗
PubMed1995

Regional distribution of growth hormone-releasing hormone (GHRH) receptor mRNA in the rat brain.

We examined the tissue distribution of growth hormone-releasing hormone (GHRH) receptor mRNA in the rat brain because several lines of evidence have suggested that GHRH plays a functional role in the brain. GHRH receptor mRNA was detected in the hypothalamus as well as pituitary, but not in olfactory bulb, caudate putamen, cerebral cortex, hippocampus, cerebellum, or brainstem by RNase protection assay. To clarify the precise localization of GHRH receptor mRNA in the hypothalamus, reverse transcription-polymerase chain reaction (RT-PCR) was used. A PCR product of the predicted size (564 bp) was detected in the periventricular, arcuate, and ventromedial nuclei, and the anterior hypothalamic area, but not in the paraventricular nucleus in the hypothalamus. These areas where GHRH receptor mRNA was detected are possible sites of GHRH action. Another band, smaller in size than that of the predicted PCR amplification product, was detected in the anterior hypothalamic area and arcuate nucleus, respectively. Hybridization analysis with a cDNA probe for GHRH receptor demonstrated that the smaller bands as well as that of the predicted size corresponded to GHRH receptor cDNA. The role of the short form of the GHRH receptor remains unknown.

Animals↗
PubMed1995

Carboxyl-terminal peptides from parathyroid hormone-related protein stimulate osteoclast-like cell formation.

The role of the carboxyl (C)-terminal portion of PTH-related protein (PTHrP) in bone resorption continues to be controversial. The present study was performed to examine the effect of C-terminal PTHrP peptides on osteoclast-like cell formation as well as bone resorption in mice. C-Terminal PTHrP peptides [human (h) PTHrP-(107-139) and hPTHrP-(107-111); 10(-10)-10(-8) M] stimulated osteoclast-like cell formation in a concentration-dependent manner in osteoblast-containing mouse bone cell cultures. Moreover, osteoclast-like cells newly formed by these peptides possessed the ability to form pits on the dentine slices. The conditioned medium from UMR-106 cells and MC3T3-E1 cells pretreated with the C-terminal peptides did not affect osteoclast-like cell formation from mouse hemopoietic blast cells derived from spleen cells. The C-terminal peptides as well as hPTHrP-(1-34) stimulated osteoclast-like cell formation from mouse hemopoietic blast cells in the absence of osteoblasts, although both amino- and C-terminal peptides were unable to support hemopoietic blast cells. Protein kinase-C inhibitors (H-7 and staurosporine) almost completely inhibited the stimulation of osteoclast-like cell formation by the C-terminal peptides in both the presence and absence of osteoblasts. The C-terminal peptides did not affect bone resorption by mature osteoclasts in osteoblast-containing mouse bone cell cultures. The present study indicates that C-terminal PTHrP peptides possess the ability to stimulate osteoclast-like cell formation in both the presence and absence of osteoblasts, possibly through the pathway involving protein kinase-C activation.

Animals↗
PubMed1995

Effects of 22-oxacalcitriol on bone metabolism in vitro: comparison with calcitriol--effects of 22-oxacalcitriol on osteoclast-like cell formation and bone-resorbing activity.

22-Oxacalcitriol (OCT), a synthetic vitamin D3 analog, can mimic the ability of calcitriol to differentiate leukemia and skin cells, to enhance the immune response and to suppress parathyroid hormone secretion, but has much less calcemic activity than that of calcitriol. The mechanism of this selective action remains not fully understood, and the actions of OCT on bone metabolism are little known. The present study was, therefore, designed to investigate the effects of OCT and calcitriol on: the proliferation and functions of osteoblastic MC3T3-E1 cells; osteoclast-like cell formation from hemopoietic blast cells in the absence of stromal cells as well as from unfractionated bone cells in the presence of stromal cells; bone resorption; and the proliferation of MC3T3-E1 cells via monocytes. 22-Oxacalcitriol and calcitriol inhibited [3H]thymidine (TdR) incorporation, alkaline phosphatase activity and collagen synthesis of MC3T3-E1 cells to a similar degree. Both OCT (10(-10)-10(-8) mol/l) and calcitriol significantly and similarly stimulated osteoclast-like cell formation from both hemopoietic blast cells and unfractionated bone cells. 22-Oxacalcitriol (10(-10) and 10(-8) mol/l) significantly stimulated bone resorption, although to a slightly lesser degree than did calcitriol. Human monocyte-conditioned medium (CM) significantly stimulated TdR incorporation into MC3T3-E1 cells. On the other hand, CM obtained from monocytes treated with calcitriol (10(-10)-10(-8) mol/l) significantly inhibited TdR incorporation in a dose-related fashion, whereas CM obtained from monocytes treated with OCT (10(-10)-10(-8) mol/l) significantly stimulated TdR incorporation in a dose-related fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1995

Re-evaluation of capillaroscopy of finger nailfold in vibration-exposed workers.

Two hundred and ninety-four vibration-exposed workers were examined for vibration disease (VD) for the worker's accident compensation. Most subjects were male. Their ages ranged from 24 to 68 years. Duration of vibration exposure ranged from 3 to 30 years. After acclimatization at 25 degrees C to 27 degrees C for at least an hour, the nailfold capillaries of the ring (or middle) finger were studied with a light microscope. A cold water immersion test (5 degrees C, 10 min) was then performed. The morphological findings of the nailfold capillaries were classified based on the criteria by Fagrell & Lundberg. A hundred and eighty subjects were diagnosed as VD and 75 as non VD, even without taking the capillaroscopic findings into consideration. The classification of the capillarograms retrospectively investigated were as follows, i.e. in 98 VD subjects 40 cases were stage A, 42 stage B, and 16 cases stage C. In 26 nonVD subjects 13 cases were stage A, 10 stage B, and 3 cases stage C, respectively. When the borderline of VD and nonVD existed between stage A and stages B and C, the sensitivity was 59.2%, specificity was 50.0%, and false positive and negative were 50.0% and 40.8%. Relationship between the capillary stage and recovery (%) of the skin temperature during the cold water immersion test was also studied. The recovery in stage C was not always lower than that in stage A. Among them, arteriography was performed in 57 cases. Despite the use of vasodilator, markedly delayed perfusion of the finger tips was observed in 28 cases. Their capillary stages were A in 12 cases, B in 11 and C in 3. The peripheral microcirculatory state in VD should be carefully evaluated in combination with appropriately selected examinations, including finger nailfold capillaroscopy.

Adult↗
PubMed1994

Short, terminally phosphorylated oligoriboguanylic acids effectively inhibit cytopathicity caused by human immunodeficiency virus.

Various synthetic ribonucleic acids were evaluated for inhibition of HIV-induced cytopathicity of cultured cells; only poly and oligoguanylic acids, but not other homopolymers, showed potent inhibitory activity. Phosphorylation of either the 5'- or 3'-end of oligoribonucleotides converted short inactive oligomers, such as dimers to effective anti-HIV agents. The efficacy of the 3'-phosphorylated phosphorothioate trimer of guanylic acid was comparable to that of other longer oligonucleotides so far reported. Phosphorothioate oligoriboguanylic acids were superior to the corresponding oligodeoxyguanylic acids in their capacity to prevent HIV cytopathicity.

Antiviral Agents↗
PubMed1994

Distribution of mRNA for CCK-B receptor in the brain of Mastomys natalensis: abundant expression in telencephalic neurons.

The distribution of cholecystokinin B (CCK-B) receptors in the Mastomys brain was studied using Northern blot analysis and in situ hybridization technique. By Northern blot analysis using 32P-labeled cDNA probe, the cortex had the highest hybridization signal of CCK-B receptor mRNA in the brain. The olfactory bulb and hippocampus showed a moderate level of signals. In situ hybridization using 35S-labeled cRNA probes revealed a wide and region-specific distribution of CCK-B receptor mRNA in the telencephalon. Throughout the cerebral cortex, labeled cells were found in all layers, with higher intensities in layers II, V and VI. Pyramidal cells of the layer II of the piriform cortex showed the highest level of signals in the brain. In the hippocampus, most of the pyramidal cells of the Ammon's horn were labeled, although labeled cells were not detected in other layers. Distinct signals were also detected in the various amygdaloid nuclei, caudate-putamen, reticular thalamic nucleus, hypothalamic ventromedial nucleus and inferior colliculus. This distribution pattern may further support the prominent existence of CCK-B receptors in the brain particularly in the telencephalon.

Animals↗
PubMed1994

Crystal structure of inorganic pyrophosphatase from Thermus thermophilus.

The 3-dimensional structure of inorganic pyrophosphatase from Thermus thermophilus (T-PPase) has been determined by X-ray diffraction at 2.0 A resolution and refined to R = 15.3%. The structure consists of an antiparallel closed beta-sheet and 2 alpha-helices and resembles that of the yeast enzyme in spite of the large difference in size (174 and 286 residues, respectively), little sequence similarity beyond the active center (about 20%), and different oligomeric organization (hexameric and dimeric, respectively). The similarity of the polypeptide folding in the 2 PPases provides a very strong argument in favor of an evolutionary relationship between the yeast and bacterial enzymes. The same Greek-key topology of the 5-stranded beta-barrel was found in the OB-fold proteins, the bacteriophage gene-5 DNA-binding protein, toxic-shock syndrome toxin-1, and the major cold-shock protein of Bacillus subtilis. Moreover, all known nucleotide-binding sites in these proteins are located on the same side of the beta-barrel as the active center in T-PPase. Analysis of the active center of T-PPase revealed 17 residues of potential functional importance, 16 of which are strictly conserved in all sequences of soluble PPases. Their possible role in the catalytic mechanism is discussed on the basis of the present crystal structure and with respect to site-directed mutagenesis studies on the Escherichia coli enzyme. The observed oligomeric organization of T-PPase allows us to suggest a possible mechanism for the allosteric regulation of hexameric PPases.

Amino Acid Sequence↗
PubMed1994

Conformation of bilirubin oxidase in native and denatured states.

The conformation of bilirubin oxidase (EC 1.3.3.5) from Myrothecium verrucaria was studied by circular dichroism (CD). The far-UV CD spectrum showed a single minimum at 215 nm and a maximum near 198 nm, suggesting the dominance of beta-sheets. There was another negative band at 187 nm that is absent from the spectra of model alpha-helix or beta-sheet. CD analysis by the method of Chang et al. agreed well with the estimates based on the Chou and Fasman sequence-predictive method, but the Provencher-Glöckner method of CD analysis agreed well with the sequence-predictive method of Garnier et al. At pH 12 the 215- and 187-nm bands completely disappeared and the protein was denatured. This denaturation was accompanied by the appearance of a large positive band at 250 nm, probably due to ionization of tyrosine residues. In 20 mM sodium dodecyl sulfate the magnitude of the 215-nm band increased, but the spectrum transformed to that of partial helices after heating at 100 degrees C. In 6 M guanidine hydrochloride the far-UV CD spectrum was monotonic and became more negative at the lower wavelength limit (near 212 nm), suggesting that the secondary structure of the protein was disrupted. However, the near-UV CD spectrum retained residual aromatic bands even after heating at 100 degrees C. Thus, our denaturation studies suggest that bilirubin oxidase has a rigid tertiary structure.

Amino Acid Sequence↗