Biomedical subjects

H Haga

Publications and source records attributed to H Haga.

At least 55 records · Page 3Linked to original sources

PubMed1998

Regulation of the PepT1 peptide transporter in the rat small intestine in response to 5-fluorouracil-induced injury.

BACKGROUND & AIMS: The oligopeptide transport system of the small intestine is resistant to mucosal injury. The mechanism of this resistance was investigated by examining the activity level and expression of the peptide transporter PepT1 in the intestine of rats treated with 5-fluorouracil. METHODS: The expression and localization of PepT1 were examined by immunoblot analysis of brush border membrane vesicles and immunohistochemical analysis of intestinal sections with PepT1-specific rabbit polyclonal antibodies. Also, Northern blot analysis was used for the expression of PepT1 messenger RNA (mRNA). RESULTS: Although the amounts of sucrase and an Na+-dependent glucose transporter protein in intestinal vesicles decreased markedly after 5-fluorouracil treatment, the amount of PepT1 protein remained largely unaffected. Immunohistochemical analysis also showed that the PepT1 immunoreactivity level was preserved in the brush border membrane of the remaining villi of 5-fluorouracil-treated rats. Levels of amino acid, glucose, and phosphate transporter mRNAs were profoundly depressed in 5-fluorouracil-treated animals, whereas the level of PepT1 mRNA conversely increased. CONCLUSIONS: The resistance of intestinal peptide transport to tissue injury may be attributable to increased synthesis of PepT1 rather than to a change in the kinetic properties of the residual absorbing cells.

Animals↗

PubMed1998

Molecular cloning and hormonal regulation of PiT-1, a sodium-dependent phosphate cotransporter from rat parathyroid glands.

The extracellular concentration of inorganic phosphate (Pi) is an important determinant of parathyroid cell function. The effects of Pi may be mediated through specific molecules in the parathyroid cell membrane, one candidate molecule for which would be a Na+-dependent Pi cotransporter. A complementary DNA encoding a Na+-Pi cotransporter, termed rat PiT-1, has now been isolated from rat parathyroid. The 2890-bp complementary DNA encodes a protein of 681 amino acids that shows sequence identities of 97% and 93% with the type III Na+-Pi cotransporters mouse PiT-1 and human PiT-1, respectively. Expression of rat PiT-1 in Xenopus oocytes revealed that it possesses Na+-dependent Pi cotransport activity. PiT-1 messenger RNA (mRNA) is widely distributed in rat tissues and is most abundant in brain, bone, and small intestine. The amount of PiT-1 mRNA in the parathyroid of vitamin D-deficient rats was reduced compared with that in normal animals and increased markedly after administration of 1,25-dihydroxyvitamin D3. Furthermore, the abundance of PiT-1 mRNA in the parathyroid was much greater in rats fed a low-Pi diet than in those fed a high-Pi diet. Thus, rat PiT-1 may contribute to the effects of Pi and vitamin D on parathyroid function.

Amino Acid Sequence↗

PubMed1998

Elastic properties of living fibroblasts as imaged using force modulation mode in atomic force microscopy.

Using the force modulation mode in atomic force microscopy, we measured elastic properties of living mouse fibroblasts (NIH3T3) in a culture medium. The topographic images of the cellular surface and the corresponding elastic images of the cellular surface were able to be captured simultaneously with high spatial resolution. The consecutive images were useful for examining time-dependent changes in the cellular surface. We observed that some cells continued to shrink and change their softness for 2 hours. Then the force modulation mode in atomic force microscopy shows potential use in analyzing time-dependent regional elastic properties of living cells with high spatial resolution.

3T3 Cells↗

PubMed1998

[Prevalence of affective disorders on the basis of DSM-III among the elderly in a rural community in Japan].

The prevalence rates of affective disorders among the elderly in a rural community according to the criteria of the third edition of Diagnostic and Statistical Manual of Mental Disorders were investigated. The survey used a two-phase method which combined a self-administered depression scale and diagnostic interviews by psychiatrists. The subjects were all 766 persons aged 65 years or older in a rural village in Japan. In the first phase, 698 persons completed a self-administered scale, the Center for Epidemiologic Studies Depression scale (CES-D). In the second phase, 83 persons scoring 12 points or more on the CES-D and an additional 8 persons who, for unknown reason, did not respond to the CES-D were assessed by psychiatrists using a modified version of the Diagnostic Interview Schedule. The subjects' physical health and life events, the presence of dementia, and other factors were taken into account when diagnoses were made. The point prevalence rates of depression without dementia as a comorbid condition by category were as follows: major depression, 0.5%; dysthymic disorder, 0.3%; and atypical depression, 0.4%. The point prevalence rates of depression with dementia as a comorbid condition were as follows: major depression, 0.7%; dysthymic disorder, 0.4%; and atypical depression, 0.4%. Major depression was more prevalent in women than in men and was more prevalent in persons aged 75 years of older than in younger subjects.

Aged↗

PubMed1998

[Relationship between nutrient intake and bone mineral density in an urban community of healthy elderly women].

The relationship between nutrient intake and bone mineral density (BMD) in a community of healthy elderly women was investigated. A three-day nutritional survey was carried out. Subjects were divided into two groups using criteria set by the Recommended Dietary Allowances for the Japanese Fifth Revision (1994). Relationship between nutritional intake and BMD was explored. Intake of energy, protein, fats, and vitamins B1 and B2 correlated positively with BMD, as did the intake of eggs, meat, legume and soya products, other vegetables and potatoes, as well as fat and oil. Those with larger average number of food ingested per day had higher average of BMD. In conclusion, the hypothesis: adequate dietary intake protects against BMD loss, agreed with the results. Sufficient nutrient and food intake is associated with BMD increase, and possibly reduced risk of osteoporosis.

Aged↗

PubMed1997

Cloning, functional expression and dietary regulation of the mouse neutral and basic amino acid transporter (NBAT).

The Na+-independent dibasic and neutral amino acid transporter NBAT is among the least hydrophobic of mammalian amino acid transporters. The transporter contains one to four transmembrane domains and induces amino acid transport activity via a b0,+-like system when expressed in Xenopus oocytes. However, the physiological role of NBAT remains unclear. Complementary DNA clones encoding mouse NBAT have now been isolated. The expression of mouse NBAT in Xenopus oocytes also induced an obligatory amino acid exchange activity similar to that of the b0,+-like system. The amount of NBAT mRNA in mouse kidney increased during postnatal development, consistent with the increase in renal cystine and dibasic transport activity. Dietary aspartate induced a marked increase in cystine transport via the b0,+ system in mouse ileum. A high-aspartate diet also increased the amount of NBAT mRNA in mouse ileum. In the ileum of mice fed on the aspartate diet, the extent of cystine transport was further increased by preloading brush border membrane vesicles with lysine. Hybrid depletion of NBAT mRNA from ileal polyadenylated RNA revealed that the increase in cystine transport activity induced by the high-aspartate diet, as measured in Xenopus oocytes, was attributable to NBAT. These results demonstrate that mouse NBAT has an important role in cystine transport.

Amino Acid Sequence↗

PubMed1997

Immunohistochemical and RT-PCR detection of Na+-dependent inorganic phosphate cotransporter (NaPi-2) in rat brain.

Expression of a renal Na+-dependent inorganic phosphate (Pi) cotransporter (NaPi-2) was studied in rat forebrain with reverse transcription and polymerase chain reaction (RT-PCR) and immunohistochemistry. RT-PCR analysis for total RNA from whole brain and sequencing of the PCR products showed expression of NaPi-2 mRNA in the brain. Immunohistochemical analysis revealed NaPi-2 staining in many nonpyramidal neurons of all six layers throughout neocortical areas and in neurons of proisocortical and periallocortical areas. NaPi-2-immunoreactive neurons were also detectable in the piriform cortex, hippocampal formation, caudate-putamen, amygdaloid nuclei and lateral geniculate nucleus. Furthermore, NaPi-2 staining was shown in ependymal cells and microvascular endothelial cells. The present results suggest that NaPi-2 is synthesized within the brain and involved in maintaining Pi homeostasis of certain neurons and/or the entire brain.

Animals↗

PubMed1997

Basaloid squamous cell carcinoma of the esophagus metastatic to the gingiva: a case report.

Basaloid squamous cell carcinoma (BSCC), a biologically high-grade variant of squamous cell carcinoma, carries a grave prognosis. In this article, we describe a rare case of BSCC of the esophagus with metastasis to the mandibular gingiva in a 63-year-old man. In addition, we provide a review of the relevant literature along with a discussion of the differential diagnosis.

Carcinoma, Basosquamous↗

PubMed1997

Advances in soil microbial ecology and the biodiversity.

Recent studies on the colony formation of soil bacteria opened the way to categorize soil bacteria into colony forming curve (CFC) groups of different growth rates. A bacterial culture collection comprising organisms from every CFC group is called an ecocollection (EC). Outlines of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were described. Phylogenetic studies by 16S rDNA sequencing showed a great diversity of culture strains of the ecocollections. A set of alternative concepts was proposed; the active and the quiescent forms of bacterial cells in soil. The former is able to be cultivated and thus counted by the plate method, while the latter is not unless it transforms into the former. Based on the results several points required for extensive cataloguing of soil bacteria were noted.

Bacteria↗

PubMed1997

Acute regulation by dietary phosphate of the sodium-dependent phosphate transporter (NaP(i)-2) in rat kidney.

Alteration of the dietary intake of phosphate (P(i)) leads to rapid changes in renal P(i) transport activity. The present study, examined the underlying cellular mechanisms of the rapid regulation, with special reference to renal P(i) cotransporter. Rats were fed either a low-P(i) (0.02%) diet (CLP rats), the low-P(i) diet followed by a high-P(i) (1.2%) diet (AHP rats), or a normal (0.6%) diet (control rats). Na(+)-dependent P(i) transport activity in the brush border membrane was significantly increased in CLP rats compared with control rats, and this activity decreased rapidly within 2 h after the change of diet in AHP rats. Kinetic analysis of P(i) transport in the AHP rats indicated that the reduction was accompanied by a decrease in the apparent Vmax for Na(+)-dependent P(i) uptake. Northern blot analysis showed no difference in the abundance of NaP(i)-2 mRNA of the kidney between AHP and CLP rats. In contrast, Western blot analysis of renal brush border membrane proteins of AHP rats indicated a significant decrease in the abundance of NaP(i)-2 protein as compared with CLP rats. Immunoreactive signals for NaP(i)-2 were detected in lysosomal fractions of AHP and CLP rats. Immunohistochemical analysis showed that, NaP(i)-2 immunoreactivity in AHP rats was largely reduced in the apical membrane of the proximal tubular epithelial cells. Neither cycloheximide nor actinomycin D affected high-P(i)-induced reduction of NaP(i)-2 protein in the brush border membrane of AHP rats, indicating that de novo protein synthesis of an unidentified regulator protein was not involved in the mechanism of this reduction. In contrast, treatment with colchicine, which disrupts microtubulers, abolished the effect of high-P(i) diet on NaP(i)-2 expression. These results suggested that rapid endocytotic internalization of NaP(i)-2 may occur specifically in the brush border membrane following an acute increase in dietary P(i) intake.

Animals↗

PubMed1997

[Mental and physical symptoms in alcoholics after alcohol withdrawal].

Much of the recent interest in the risk factors of relapse in alcoholics has focused on the withdrawal depressive state. Although the clinical relevance of this syndrome is often acknowledged, definite empirical research on subjective symptoms has not been presented in detail. Therefore, the purpose of this paper is to explore the characteristics of mentally or physically subjective symptoms of alcoholics and to discuss the risk factors to "slip". To evaluate the subjective symptoms, the health questionnaire that is composed of 62 items was applied to 73 admitted alcoholics. The principal component analysis obtained for the questionnaire of mental symptoms extracted five factors as followed, 1) feeling of estrangement or emptiness, 2) anxiety or impatient, 3) depressive mood or sleeping disturbance, 4) endogenous depressive factor, 5) unstable emotion. Additionally, five factors on physical symptoms were extracted as follows, 1) autonomic dysregulation related to neurasthenic state, 2) autonomic dysregulation related to hysterical neurosis, 3) loss of libido, 4) appetite loss, 5) dry mouth or sweating. These findings emphasized that many alcoholics felt the feeling of maladjustment and emotionally unstable under the "sobriety" state. These also suggest the "slip" of alcoholics should depend on expectation to reduce their tension, conflict and frustration under the influence of alcohol.

Alcoholism↗

PubMed1996

The recombination mediated by double-strand breaks in extrachromosomal DNA substrate carrying mouse immunoglobulin switch regions S mu and S gamma 2b.

Recombination in mouse cells was analyzed using extrachromosomal DNA substrates carrying the mouse immunoglobulin switch regions S mu and S gamma 2b. Recombination was detected at a frequency of 10(-2)-10(-3) in mouse fibroblasts and in pre-B cell lines, but at a low frequency in a scid fibroblast cell line. Restriction enzyme digestion profile revealed that most recombination occurred between the CMV promoter region, which neighbors the S mu upstream region, and the S gamma 2b region. However, frequency of direct recombination between the CMV promoter region and the S gamma 2b region was low as measured by the substrate-lacking S mu region. Nucleotide sequence analysis showed that recombination occurred between several homologous base-pairs, and extranucleotides were frequently found at the recombination junctions. These results indicate that recombination took the form of the recombination mediated by double-strand breaks. Double-strand breaks likely occurred in the S mu and/or S gamma 2b region, and the ends joined.

Animals↗

PubMed1996

Effects of truncation of the COOH-terminal region of a Na+-independent neutral and basic amino acid transporter on amino acid transport in Xenopus oocytes.

To determine the role of a neutral and basic amino acid transporter (NBAT) in amino acid transport, we microinjected several COOH-terminal deletion mutants of NBAT cRNA into Xenopus oocytes and measured transport activity for arginine, leucine, and cystine in the presence and absence of sodium. Wild-type NBAT significantly stimulated the uptake of all three amino acids 10-20-fold compared with controls. On the other hand, no mutant, except a Delta511-685 mutant, stimulated the uptake of these amino acids. The Delta511-685 mutant significantly increased the uptake of arginine. In the presence of sodium, the Delta511-685 mutant also increased the uptake of leucine. The Delta511-685 mutant did not stimulate cystine uptake in the presence or absence of sodium. The stimulation of arginine uptake by the Delta511-685 mutant was inhibited by a 100-fold excess of unlabeled leucine in the presence of sodium. Inhibition of L-arginine uptake by L-homoserine was seen only in the presence of sodium, and an increase in the inhibition of L-arginine uptake by L-histidine was seen when the extracellular pH was decreased. Furthermore, an inward current in oocytes injected with the Delta511-685 mutant was recorded electrophysiologically when basic amino acids were applied. Homoserine was also taken up, but sodium was necessary for their transport. These properties of the Delta511-685 mutant correspond to those of the y+ amino acid transporter. If NBAT is a component of the b0,+-like amino acid transport system, it is unlikely that a mutant protein (Delta511-685) is able to stimulate an endogenous y+-like transport system. These results suggest that NBAT functions as a activator of the amino acid transport system in Xenopus oocytes.

Amino Acid Sequence↗

PubMed1996

The basic amino acid transporter (rBAT)-like immunoreactivity in paraventricular and supraoptic magnocellular neurons of the rat hypothalamus.

In the rat hypothalamus, the basic amino acid transporter (rBAT)-like immunoreactivity was analyzed by immunohistochemistry using an antibody against the 15-amino acid sequence of the deduced rat rBAT protein. In the supraoptic and the paraventricular nuclei, magnocellular neurons exhibited the marked rBAT-like immunoreactivity in intracellular structures but not in the plasma membrane. The results suggest that the rBAT serves as an intracellular amino acid transport system in magnocellular neurons.

Amino Acid Sequence↗

PubMed1996

Sequence, tissue distribution and developmental changes in rat intestinal oligopeptide transporter.

Complementary DNA clones encoding the rat PepT1 small-intestinal oligopeptide transporter were isolated from a jejunal library by cross-hybridization with a rabbit PepT1 cDNA probe. The cDNA sequence indicates that rat PepT1 is composed of 710 amino acids and shows 77% and 83% amino acid sequence identity with rabbit and human PepT1, respectively. Northern blot analysis detected rat PepT1 mRNA in the small intestine and kidney. Intestinal PepT1 mRNA levels were highest in 4-day old rats, and then decreased reaching the adult level by day 28 after birth. These results indicate that the expressions of PepT1 gene change markedly during development.

Age Factors↗

PubMed1996

Gastric duplication cyst: evaluation by endoscopic ultrasonography and magnetic resonance imaging.

Endoscopic ultrasonography (EUS) and magnetic resonance imaging (MRI) are becoming popular methods for examining tumorous lesions along the upper gastrointestinal tract. Though duplication cysts are uncommon, EUS findings from gastric duplication cysts have accumulated and proven very useful for preoperative diagnosis. There have been few reports, however, concerning MRI findings from these cysts. We report herein the case of a 25-year-old man with a gastric duplication cyst. EUS demonstrated a cystic mass adjacent to the fourth layer of the stomach wall. MRI revealed a cyst containing low signal-intensity fluid and high signal-intensity fluid separated by levels. In addition to the characteristic findings from preoperative examinations, the unique histological findings from the cyst are also described.

Adult↗

PubMed1996

Transfection of wild-type TP53 induces differentiation in human gingival carcinoma cells.

We investigated the effects of transfection of wild-type TP53 on the growth properties of a human gingival carcinoma cell line, KOSC-3, in which the TP53 gene is mutated at codon 248 and overexpressed. The wild-type TP53 expression plasmid, pCDM8-p53/neo and the control plasmid, pCDM8/neo, were each stably transfected into KOSC-3 cells by using the calcium phosphate method. The number of G418-resistant colonies from wild-type TP53-transfected cells was approximately half that from plasmid controls. Exogenous wild-type TP53 transcripts were identified in four of the 20 G418-resistant clones analysed by reverse transcription PCR. Although the growth rates of the wild-type TP53+ clones did not drastically change during log phase, their saturation density was significantly reduced. The wild-type TP53+ cells were morphologically flat and enlarged when cultured in vitro, and were less able to form colonies in soft agar. In nude mice, the wild-type TP53+ clones formed subcutaneous tumours with conspicuous keratinisation and notable cell death that was not manifested in the parental and plasmid control cells. These findings indicate that the wild-type TP53 gene, even when it coexists with a mutated form, may function as a growth suppressor and differentiation inducer under restricted conditions in gingival squamous cell carcinoma.

Animals↗

PubMed1996

Salivary duct carcinoma: a clinicopathologic study of three cases with a review of the literature.

Three cases of salivary duct carcinoma are presented. They occurred in a 60 year old man, a 66 year old man and a 57 year old woman. All of the lesions were located in the parotid gland. The tumor size ranged from 3 to 5 cm across the largest diameter. Facial paralysis was observed in two cases. Histologically, intraductal and invasive adenocarcinoma showing papillary, cribriform, and solid patterns with comedolike necrosis was observed. Immunohistochemically, the tumor cells were positive for keratin and epithelial membrane antigen. No myoepithelial cells were demonstrated within the tumor by staining for S-100 protein, alpha-smooth muscle actin or muscle specific actin. Ultrastructurally, intracytoplasmic lumina with microvilli, a moderate number of mitochrondria, lysosomes, and tight junctions were found. Regional lymph node metastasis was observed in one case, and distant metastasis developed in two cases. All of the patients were treated with adjuvant postoperative irradiation. One patient died of disease at 11 months after the initial diagnosis, another was alive with disease at 8 months, and the third patient was alive without disease at 2 years and 3 months. Salivary duct carcinoma should be differentiated from low-grade salivary gland carcinomas using morphologic and clinical criteria because of its poor prognosis even with aggressive therapy.

Adenocarcinoma↗