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Biomedical subjects

K Kawase

Publications and source records attributed to K Kawase.

At least 37 records · Page 2Linked to original sources
PubMed1998

Promoter analysis of RPE65, the gene encoding a 61-kDa retinal pigment epithelium-specific protein.

PURPOSE: To identify the functional promoter region and cis-acting elements that regulate the expression of RPE65, the retinal pigment epithelium (RPE)-specific gene responsible for certain forms of autosomal recessive childhood-onset severe retinal dystrophy. METHODS: A human genomic DNA clone containing the 5'-flanking region of RPE65 was isolated and, 4.0 kb proximal to the transcription start site, was sequenced and analyzed for the presence of transcription factor-binding sites. Promoter activity was assayed by transient transfection of luciferase reporter constructs containing nested deletions of the upstream sequence in the human RPE cell lines ARPE19 and D407, as well as in the SK-Mel-28 and HeLa cell lines. Specific DNA protein-binding sites present in the 340 bp upstream of the transcription start site were identified by DNase I footprint analysis. RESULTS: Sequence analysis places the polymorphic marker, D1S2803, within the RPE65 upstream region and identifies a number of sequences homologous to the gene encoding the cellular retinaldehyde-binding protein. Functional analysis indicates that basal promoter activity is conferred by the sequence from -83 to +39 and is approximately equivalent in all cell lines tested, with no other control elements detected in 3.6 kb of the upstream sequence. At least eight protected regions are identified in DNase I footprint assays, including sequences corresponding to the predicted TATA box, AP-4, and nuclear factor-1 DNA protein-binding sites. CONCLUSIONS: These findings localize the basal promoter activity of RPE65, identify potential cis-acting elements that act as positive regulators of gene expression, and suggest that additional regulatory elements are likely to be involved in restricting gene expression to the retinal pigment epithelium. Identification of promoter elements and genetic markers in the upstream sequence will enable the screening of patients with retinal degeneration for possible mutations that affect RPE65 expression.

Base Sequence↗
PubMed1998

Correlation of the peripapillary atrophy area with optic disc cupping and disc hemorrhage.

PURPOSE: To investigate the association of the peripapillary atrophy area with disc cupping area and disc hemorrhage in subjects who underwent ocular examination as part of a routine physical examination. METHODS: We reviewed plain color fundus photographs taken of 12,140 eyes of 6,070 subjects as part of a routine health examination. The refractive error in these eyes was not known. Using a computerized image analysis system, we measured the area of peripapillary atrophy (zone beta), the optic disc, and optic disc cupping by means of planimetry in 8,842 eyes of 4,421 subjects with fundus images of good quality. RESULTS: The ratio of cup area to disc area was significantly greater in eyes with peripapillary atrophy (0.36 + 0.09) than in eyes without peripapillary atrophy (0.34 + 0.07), and the ratio of peripapillary atrophy area to disc area was significantly greater in eyes with disc hemorrhage (0.26 + 0.34) than in those without disc hemorrhage (0.09 + 0.18). Moreover, in eyes with peripapillary atrophy, the ratio of cup area to disc area was significantly larger in eyes with disc hemorrhage (0.48 + 0.08) than in those without disc hemorrhage (0.36 + 0.09). These results remained statistically unchanged even after "glaucomatous" eyes were excluded from the study. CONCLUSION: Peripapillary atrophy appears to be associated with a higher degree of cupping of the optic disc and disc hemorrhage, and the results suggest an association between peripapillary atrophy and glaucomatous optic neuropathy.

Female↗
PubMed1997

Augmented inhibition of growth of Candida albicans by neutrophils in the presence of lactoferrin.

The combined inhibitory effects of neutrophils and lactoferrins on the growth of Candida albicans were examined. Murine or human neutrophils partially inhibited growth of C. albicans when cultured with C. albicans in vitro. The growth inhibition was augmented by a combination of neutrophils and more than 30 microg/ml of bovine lactoferrin or 1 microg/ml of human lactoferrin, concentrations less than 1/10-1/200 their inhibiting concentrations when used alone. The inhibition of C. albicans was also enhanced by combination of neutrophils and bovine apolactoferrin or iron-bound holo-lactoferrin, but not by transferrin. Combination effects of neutrophils and lactoferrin were also observed in a condition where there was no contact between neutrophils and Candida cells. These results suggest that neutrophils inhibit the growth of C. albicans regardless of whether there is direct contact between them and Candida cells: neutrophil growth inhibition effects were augmented in the presence of a physiological concentration of lactoferrin, perhaps through some action of lactoferrin other than chelation of ferric ion.

Animals↗
PubMed1997

Effects of choreito consumption on urine variables of healthy cats fed a magnesium-supplemented commercial diet.

OBJECTIVE: To investigate the effect of choreito consumption (500 mg/kg of body weight/d) on struvite crystal formation and signs of lower urinary tract disease (LUTD) in cats consuming a commercial canned diet with 0.5% added inorganic magnesium. SAMPLE POPULATION: 6 male and 6 female adult cats, all considered to be clinically normal on the basis of physical examination findings; results of CBC, serum biochemical analyses, urinalyses, and urine cultures; and freedom from urolithiasis on the basis of urethrocystoscopic (females) or urethrocystographic (males) findings. PROCEDURE: Diets were fed for 12 weeks, or until appearance of signs of LUTD, including dysuria, hematuria, urine pH > 7.0, and severe struvite crystalluria. Presence of at least 2 of these signs was required for removal from study. Urine specimens were examined for electrolytes, struvite crystal content, and hematuria. RESULTS: Results for urine variables were compared between groups at 4 weeks, because of reduction in cat numbers attributable to removal from study. Struvite crystal content of 24-hour urine specimens was significantly lower for cats fed the choreito-containing diet. Moreover, frequency and severity of hematuria were significantly decreased in cats fed the choreito-containing diet. Correlation between hematuria and struvite crystal content was not observed in either group. Additionally, all 6 cats fed the diet without choreito had been removed from study by day 58 because of signs of LUTD. Of the 6 cats fed the choreito-containing diet, 2 completed the 12-week study. CLINICAL RELEVANCE: Choreito may be beneficial for relief of some signs of struvite-associated LUTD disease in cats.

Analysis of Variance↗
PubMed1997

Effects of choreito and takushya consumption on in vitro and in vivo struvite solubility in cat urine.

OBJECTIVE: To determine the effects of the takushya portion of choreito, a traditional Chinese treatment for urolithiasis, on urine and struvite crystal variables in cats fed diets containing takushya. SAMPLE POPULATION: 6 male and 6 female adult cats, all considered to be clinically normal on the basis of physical examination findings, results of CBC, serum biochemical analyses, urinalyses, and urine cultures; and freedom from urolithiasis on the basis of urethrocystoscopic (females) or urethrocystographic (males) findings. PROCEDURE: Cats were fed a commercial canned diet supplemented with 0.1-mg of takushya/kg of body weight, or with 0.5 mg of choreito/kg. Diets were fed, using a Latin-square design, to 3 groups of 4 cats (2 male, 2 female) each for 2 weeks, followed by blood and 24-hour urine sample collections. RESULTS: Consumption of takushya, which comprises 20% by weight of choreito, was not associated with adverse effects in cats at the amounts provided during the period of study. Moreover, takushya was responsible for most of the effect of choreito consumption on reduction of urine pH, and approximately half its ability to reduce struvite crystal formation in cat urine. CLINICAL RELEVANCE: Alternative treatments for struvite urolithiasis in cats may be feasible.

Analysis of Variance↗
PubMed1996

Cooperative anti-Candida effects of lactoferrin or its peptides in combination with azole antifungal agents.

The effects of lactoferrin (LF), an antimicrobial protein secreted in body fluids, and its peptides in combination with azole antifungal agents were investigated by the micro-broth-dilution method in a study of Candida albicans. In the case of LF, its pepsin hydrolysate (LFhyd) or the LF-derived antimicrobial peptide Lactoferricin B (LF-B), the concentrations required to inhibit the growth of Candida decreased in the presence of relatively low concentrations of clotrimazole (CTZ). The minimum inhibitory concentration (MIC) of all azole antifungal agents tested was reduced by 1/4-1/16 in the presence of a sub-MIC level of each of these LF-related substances. Polyene and fluoropyrimidine antifungal agents did not show such a combined effect with these LF-related substances. The anti-Candida activity of LF or LF-B in combination with CTZ was shown to be synergistic by checkerboard analysis. These results indicate that LF-related substances function cooperatively with azole antifungal agents against C. albicans.

Antifungal Agents↗
PubMed1996

[FAM as a palliative chemotherapy for gastric cancer with bone metastasis].

A 50-year-old male was admitted to our hospital with severe malaise and lumbar pain. He suffered from diffuse bone metastasis of gastric cancer (mod. tub. adenocarcinoma) and DIC. In order to palliate his severe bone pain and bleeding tendency, FAM (5-fluorouracil 600 mg/body day 1, 7, 29, 36; doxorubicin 40 mg/body day 1, 29; and mitomycin C 12 mg/body day 1) combination chemotherapy was used. After administration of FAM therapy, bone pain and bleeding tendency due to DIC disappeared. For three months after initiation of chemotherapy, the patient's quality of life was maintained fairly well. Adverse reactions of FAM therapy were only appetite loss for several days. FAM therapy might be a useful regimen for palliation of bone pain and DIC due to diffuse bone metastasis of gastric cancer.

Adenocarcinoma↗
PubMed1995

Molecular characterization of the human gene encoding an abundant 61 kDa protein specific to the retinal pigment epithelium.

The retinal pigment epithelium (RPE) of the eye expresses an abundant 61 kDa protein (RPE65), that is developmentally regulated and tissue-specific. In our efforts toward understanding the specialized functions and development of the RPE, and the origins of inherited retinal degenerations, we have characterized the human gene encoding the 61 kDa protein. This is the first structural characterization of a gene transcribed specifically in the RPE. The gene maps to human chromosome 1p31. The sequence encoding the transcript spans over 20 kb, and is interrupted by 13 introns. A putative transcription start site lies 54 bp upstream of the initiation codon. A single transcript of approximately 2.9 kb is present in human RPE, and is not detected in other tissues. The deduced 533 amino acid sequence of the human protein is 98.7% identical to the bovine, but shows no significant similarity to any other entry in the databases. Expression of the 61 kDa protein appears to depend on the presence of environmental cues, since the corresponding transcripts are rapidly lost from RPE cells established in culture. Down regulation may occur post-transcriptionally, since AU-rich elements proposed to target RNA for rapid degradation are present throughout the 3'-untranslated region. The tissue-specific expression, high abundance, evolutionary conservation, developmental regulation, and sequence of the 3'-untranslated region suggest that the 61 kDa protein is the product of a functionally important gene whose expression is tightly regulated.

Amino Acid Sequence↗
PubMed1994

Prostaglandin D2-sensitive, sleep-promoting zone defined in the ventral surface of the rostral basal forebrain.

The site of action for the sleep-promoting effect of prostaglandin (PG) D2 was extensively examined in the brain of adult male rats (n = 231). PGD2 was administered at 100 pmol/0.2 microliter per min for 6 hr (2300-0500 hr) through chronically implanted microdialysis probes or infusion cannulae. Among the administrations of PDG2 by dialysis probes (n = 176), only those (n = 8) to a ventro-rostral part of the basal forebrain by the probes implanted on the midline consistently increased slow-wave sleep (SWS), by 51 +/- 6 min (mean +/- SEM) above the baseline value (111 +/- 11 min). Since this area is separated by a cleft into right and left regions, the results were interpreted to mean that, through this cleft, PGD2 diffused in the subarachnoid space over the adjacent ventral surface, where it had the effect of promoting sleep. When PGD2 was directly infused into the subarachnoid space (n = 55), extraordinary increases exceeding 90 min were consistently attained for the SWS at sites located between 0.5 and 2 mm rostral to the bregma and between 0 and 1.2 mm lateral to the midline defined according to the stereotaxic coordinates adopted from the brain atlas of Paxinos and Watson [Paxinos, G. & Watson, C. (1986) The Rat Brain in Stereotaxic Coordinates (Academic, San Diego)]. Thus, we demarcated a "PGD2-sensitive, sleep-promoting zone" within this region in the ventral surface of the rostral basal forebrain. During the bilateral infusion of PGD2 into the subarachnoid space of this zone, the hourly mean SWS level of the nocturnal animals (n = 6) in the night reached the maximum at the second hour of the infusion period; this maximum hourly SWS level, corresponding to the daytime level of the same animals, lasted until the end of PGD2 infusion.

Animals↗
PubMed1994

Lactoferrin inhibits cholesterol accumulation in macrophages mediated by acetylated or oxidized low-density lipoproteins.

When macrophages are incubated with acetylated or oxidized low-density lipoproteins (Ac- or OxLDL), cellular cholesteryl esters (CE) increase significantly. In the present study, we investigated the effect of whey protein on Ac- or OxLDL mediated accumulation of CE in macrophages and found that lactoferrin (Lf), a minor protein component of whey, inhibits the accumulation of CE dose-dependently. In the presence of bovine Lf (1 mg/ml), CE accumulation in macrophages incubated with AcLDL (100 micrograms of protein/ml) decreased by more than 80%. Human Lf was less potent than bovine Lf, and bovine transferrin had no effect. Binding of 125I-AcLDL to macrophages was also inhibited by Lf. Agarose gel electrophoresis revealed that Lf binds to Ac- or OxLDLs and neutralizes their negative charges. These results indicate that Lf inhibits the binding of modified LDLs to macrophages by direct interaction with modified LDLs, resulting in their loss of function as ligands of the scavenger receptor. Modification of the arginine residues of Lf with 1,2-cyclohexanedione abolished its ability to bind to AcLDL, suggesting that a region rich in basic amino acid residues near the N-terminus of Lf, which resembles the ligand-binding site of the scavenger receptor, may be responsible for this binding ability. As a result, the inhibitory effect of Lf on CE accumulation in macrophages was significantly weakened by this modification. Our results suggest the possibility that Lf in the blood stream may act as an anti-atherogenic agent in vivo.

Amino Acid Sequence↗
PubMed1994

Effects of prostaglandin D2, lipoxins and leukotrienes on sleep and brain temperature of rats.

Prostaglandin (PG) D2 and four lipoxygenase-derived eicosanoids [lipoxins (LX) A4 and B4, and leukotrienes (LT) C4 and D4] were examined for their effects on sleep and brain temperature in freely-behaving rats. In the first series of experiments, PGD2 was infused into the third ventricle at four different locations between 23:00 and 05:00. In a location apposed to the medial preoptic area (MPO), PGD2 at doses 1, 10 and 100 pmol/min, increased the slow wave sleep (SWS) by 23% (p < or = 0.01), 35% (p < or = 0.05) and 44% (p < or = 0.01), respectively, during the infusion period. In the second series of experiments, LXs and LTs were infused at the location apposed to MPO. Significant increases in SWS were detected with LXA4 at 100 pmol/min (14%, p < or = 0.05), LXB4 at 100 pmol/min (20%, p < or = 0.05), and LTD at 10 pmol/min (17%, p < or = 0.05). An increase in paradoxical sleep (PS) was produced by PGD2 at 1 and 10 pmol/min infusion (p < or = 0.05), but not by any of the lipoxygenase-derived eicosanoids examined. PGD2 also elevated the mean brain temperature during infusion by 0.2 degrees C and 0.9 degrees C at infusion doses 10 and 100 pmol/min, respectively. But PGD2 infusion at 1 pmol/min did not elevate the brain temperature. LXs (excluding LXB4 at 100 pmol/min) and LTs did not alter the brain temperature significantly at the tested doses. We conclude that PGD2 is the most effective sleep promoter among the eicosanoids examined so far.

Animals↗
PubMed1994

The yeast MOT2 gene encodes a putative zinc finger protein that serves as a global negative regulator affecting expression of several categories of genes, including mating-pheromone-responsive genes.

The STE4 gene encodes the beta subunit of a heterotrimeric G protein that is an essential component of the pheromone signal transduction pathway. To identify downstream component(s) of Ste4, we sought pseudo-revertants that restored mating competence to ste4 mutants. The suppressor mot2 was isolated as a recessive mutation that restored conjugational competence to a temperature-sensitive ste4 mutant and simultaneously conferred a temperature-sensitive growth phenotype. The MOT2 gene encodes a putative zinc finger protein, the deletion of which resulted in temperature-sensitive growth, increased expression of FUS1 in the absence of pheromones, and suppression of a deletion of the alpha-factor receptor. On the other hand, sterility resulting from deletion of STE4 was not suppressed by the mot2 deletion. These phenotypes are similar to those associated with temperature-sensitive mutations in CDC36 and CDC39, which are proposed to encode general negative regulators of transcription rather than factors involved in the pheromone response pathway. Deletion of MOT2 also caused increased transcription of unrelated genes such as GAL7 and PHO84. Overexpression of MOT2 suppresses the growth defect of temperature-sensitive mutations in CDC36 and CDC39. These observations suggest that Mot2 functions as a general negative regulator of transcription in the same processes as Cdc36 and Cdc39.

Amino Acid Sequence↗
PubMed1994

Development of hybrid type artificial bone marrow using sintered hydroxyapatite.

In vivo inducement of hybrid-type artificial bone marrow with hemopoietic inductive microenvironment (HIM) in sintered hydroxyapatite (HA) chamber was carried out. This research is important to disclose the mechanisms of hemopoiesis and is useful for clinical application. In the evolution of vertebrates, cartilage of the inner skeleton changed into bone, having biomechanical properties to form bone marrow cavities. The hemopoietic nests immigrated into the cavities from the spleen. We should be able to induce hemopoietic nests in a hydroxyapatite chamber in place of bone, if we can find optimal structural conditions. Therefore, we tried to artificially induce a hematopoietic field in muscles using sintered porous tubular hydroxyapatite and new type hydroxyapatite plate made by high-pressure gas technique. As a result, not only in the pore sites of tubular hydroxyapatite artificial bone, but at the surface of the new type hydroxyapatite plate implanted in the dorsal muscles, marked differentiation of bone marrow cell clusters of the hematopoietic field could be observed.

Animals↗
PubMed1994

Effects of choreito consumption on struvite crystal growth in urine of cats.

The effect of a dietary supplement, choreito, on in vitro struvite crystal growth in feline urine was evaluated. Adult specific-pathogen-free cats (4 females, 4 males) considered to be clinically normal on the basis of physical examination findings and normal results of CBC, serum biochemical analyses, and urinalyses obtained before the beginning of the study were used. Before 24-hour urine sample collections were made, cats were fed a commercial canned diet with 0 or 500 mg of choreito supplement/kg of body weight for at least 2 weeks in a cross-over design with 4 cats/treatment. Filtered urine samples were analyzed for urine pH, specific gravity, osmolality, and urine electrolytes. The struvite activity product was calculated, using a statistical software program that calculates urine saturation. Urine samples were placed in wells of cell culture plates, increasing concentrations of ammonium hydroxide were added to adjacent wells to stimulate struvite crystal growth, and the plates were incubated at 37 C. Crystal growth was assessed by determination of number of crystals and supersaturation index by direct visualization, using an inverted microscope. Supplementation of the diet with choreito (at this concentration) did not change urine pH, specific gravity, osmolality, urine electrolyte composition, or calculated struvite activity product. However, supplementation significantly (P < 0.05) reduced crystal number and supersaturation index. These results indicate that direct observation of struvite crystal formation in whole urine may more accurately predict the effects of treatments to prevent or treat struvite urolithiasis than do calculations based on electrolyte concentration that do not account for the effect of urine macromolecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Intervention of maternal transmission of HTLV-1 in Nagasaki, Japan.

Seroepidemiological and laboratory virological evidences strongly suggested that endemicity of HTLV-1 in Nagasaki Japan depends on maternal infant infections via breast milk. The most obvious way to prove this concept was an intervention study with refraining from breast-feeding by carrier mothers. Most infected babies seroconverted by the age of 12 months, which made it possible to diagnose the infection at the age of 12 months for the statistical purpose. Serology and PCR on both adults and children were consistent each other, suggesting the absence of seronegative carriers. The intervention study revealed that approximately 80% of maternal infection was prevented by refraining from breast feeding by carrier mothers. The remaining fraction of infections in formula-fed babies suggested an alternative infection pathway. Although intrauterine infections has been suggested by others to explain the PCR-positive cord blood samples. However, groups of cord blood-positive children and seroconverted children were distinct each other. Therefore, the presence of HTLV-1 provirus in the cord blood can not be a marker of intrauterine infection. Mothers who infected a child has approximately 10 times higher risk of another infection for the next baby than those who did not.

Breast Feeding↗
PubMed1993

Intravenous administration of inorganic selenium compounds, inhibitors of prostaglandin D synthase, inhibits sleep in freely moving rats.

Prostaglandin (PG) D2 has been postulated to be an endogenous sleep-promoting factor. Biosynthesis of PGD2 is catalyzed by PGD synthase (prostaglandin-H2 D-isomerase, EC 5.3.99.2), the activity of which is inhibited by inorganic selenium compounds such as SeCl4 and Na2SeO3. We recently examined the effect of intracerebroventricular administration of these selenium compounds on sleep in rats, and demonstrated time- and dose-dependent sleep inhibition. To establish whether this effect of selenium is also produced when the compound is administered systemically, we devised a procedure for intravenous catheterization and examined the effect of these selenocompounds on sleep-wake activity in freely moving rats (n = 35). Each test compound was administered into the inferior vena cava continuously between 11.00 and 17.00 h on the experimental day. SeCl4 time- and dose-dependently inhibited sleep at infusion rates of 5, 7.5, 10 and 20 nmol/microliters per min. During the SeCl4 infusion at 20 nmol/microliters per min, slow-wave sleep and paradoxical sleep were reduced to 63% and 50% of their respective baseline values. Na2SeO3 exhibited a similar sleep inhibition, though Na2SO3 was ineffective. Infusion of SeCl4 at 10 nmol/microliters per min or below produced no consistent changes in the mean brain temperature, or food and water intake during the infusion period. During the nocturnal period subsequent to SeCl4 infusion, sleep was increased by a rebound phenomenon, while a decrease in brain temperature and inhibition of food and water intake dose-dependently occurred. We conclude that systemic administration of these PGD synthase inhibitors has a sleep-reducing potency.

Animals↗
PubMed1993

Killing of Candida albicans by lactoferricin B, a potent antimicrobial peptide derived from the N-terminal region of bovine lactoferrin.

Candida albicans was found to be highly susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by enzymatic cleavage of bovine lactoferrin. Effective concentrations of the peptide varied within the range of 18 to 150 micrograms/ml depending on the strain and the culture medium used. Its effect was lethal, causing a rapid loss of colony-forming capability. 14C-labeled lactoferricin B bound to C. albicans and the rate of binding appeared to be consistent with the rate of killing induced by the peptide. The extent of binding was diminished in the presence of Mg2+ or Ca2+ ions which acted to reduce its anticandidal effectiveness. Binding occurred optimally at pH 6.0 and killing was maximal near the same pH. Such evidence suggests the lethal effect of lactoferricin B results from its direct interaction with the cell surface. Cells exposed to lactoferricin B exhibited profound ultrastructural damage which appeared to reflect its induction of an autolytic response. These findings suggest that active peptides of lactoferrin could potentially contribute to the host defense against C. albicans.

Amino Acid Sequence↗