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Biomedical subjects

H Hara

Publications and source records attributed to H Hara.

At least 217 records · Page 12Linked to original sources
PubMed1999

Ingestion of guar-gum hydrolysate partially restores calcium absorption in the large intestine lowered by suppression of gastric acid secretion in rats.

We examined the effects of feeding guar-gum hydrolysate (GGH), a highly fermentable form of dietary fibre with low viscosity, on Ca absorption in the small and large intestines in rats under conditions in which gastric acid secretion was suppressed by a proton pump inhibitor, omeprazole. We also examined the role of the caecum in influencing these effects. The study was designed in a 2 x 2 x 2 factorial arrangement with two diet (GGH-containing (50 g/kg diet) and GGH-free diets) groups, two injection (omeprazole and vehicle) groups and two operation (sham and caecectomy) groups. Apparent Ca absorption was lower in rats administered omeprazole (30 mg/kg body weight per d) for 8 d than in rats administered the vehicle. Ingestion of GGH led to partial restoration of Ca absorption decreased by omeprazole treatment. However, this increment in Ca absorption was not sufficient to meet requirements because the dietary Ca level (3.0 g/kg diet) was the minimum requirement for the intact rats. The small increment in Ca absorption caused by the GGH diet was completely abolished by caecectomy. Soluble Ca pools in the caecal and colonic contents were increased by feeding GGH, and the soluble Ca concentrations were much higher than the Kt values of the Ca active transport system in the large intestine or the serum Ca concentration. These findings suggest that Ca solubilization is not a limiting factor for Ca absorption in the large intestine. Apparent Mg absorption was clearly lower in caecectomized rats than in sham-operated rats, and higher in the GGH-fed groups than in the groups fed on the GGH-free diet, even in the case of caecectomized rats. We conclude that Ca absorption lowered by inhibition of gastric acid secretion is partially restored in rats fed with GGH, but the increment is not sufficient to meet requirements.

Animals↗
PubMed1998

Generation of triplet and cation-radical bacteriochlorophyll a in carotenoidless LH1 and LH2 antenna complexes from Rhodobacter sphaeroides.

The LH1 antenna complex and a native form of the LH2 complex were isolated from the carotenoidless R26 and R26.1 mutants of Rhodobacter sphaeroides by the use of a new detergent, sucrose monocholate. One-color, pump-and-probe transient Raman spectroscopy of these complexes using 351 nm, approximately 50 ps pulses showed the generation of the triplet state of bacteriochlorophyll a (BChl a), whereas measurements using 355 nm, approximately 12 ns pulses showed the generation of BChl a cation radical. Subpicosecond to nanosecond time-resolved absorption spectroscopy using 388 nm, 200 fs pulses for excitation showed rapid (<1 ps) generation of the triplet state and fast decay (<10 ps) of the singlet state of BChl a. Microsecond absorption spectroscopy confirmed the generation of BChl a cation radical. EPR spectroscopy using 532 nm, approximately 5 ns pulses for excitation established the generation of BChl a cation radical. The EPR line width suggested that the unpaired electron is shared by two BChl a molecules. In LH1, the yield of BChl a cation radical per complex was estimated to be about 80% of that in the reaction center, and in LH2 about 50%. Thus, rapid generation of the triplet state, and its subsequent transformation into the cation-radical state of BChl a have been shown to be intrinsic properties of B870 and B850 BChl a assembly in the carotenoidless LH1 and LH2 antenna complexes. In the case of the carotenoid-containing LH2 complex, the triplet states of BChl a and carotenoid (spheroidene) were generated immediately after excitation, but the triplet-state BChl a was quenched efficiently by the carotenoid so that no BChl a cation radical was generated. Thus, the photoprotective function of the carotenoid in this antenna complex is shown.

Bacterial Proteins↗
PubMed1998

Effect of a probiotic formula on intestinal immunoglobulin A production in healthy children.

The anti-infectious effect of probiotics has recently been reported and one mechanism may be the non-specific stimulation of immunity. This study was performed to elucidate the influence of a probiotic formula on intestinal microflora and local immunity in healthy children. A follow-up formula containing viable bifidobacteria was given to seven healthy Japanese children (15 to 31 months old) for 21 days. During intake of the formula, the administered strain was detected in feces from five subjects (71%) and total fecal bifidobacteria slightly increased. Fecal levels of total IgA and anti-poliovirus IgA during intake of the formula were significantly higher than those before intake (P < 0.05). The increase in local IgA levels resulting from ingestion of the probiotic formula may contribute to enhancement of the mucosal resistance against gastrointestinal infections.

Antibodies, Viral↗
PubMed1998

Defects in regulation of apoptosis in caspase-2-deficient mice.

During embryonic development, a large number of cells die naturally to shape the new organism. Members of the caspase family of proteases are essential intracellular death effectors. Herein, we generated caspase-2-deficient mice to evaluate the requirement for this enzyme in various paradigms of apoptosis. Excess numbers of germ cells were endowed in ovaries of mutant mice and the oocytes were found to be resistant to cell death following exposure to chemotherapeutic drugs. Apoptosis mediated by granzyme B and perforin was defective in caspase-2-deficient B lymphoblasts. In contrast, cell death of motor neurons during development was accelerated in caspase-2-deficient mice. In addition, caspase-2-deficient sympathetic neurons underwent apoptosis more effectively than wild-type neurons when deprived of NGF. Thus, caspase-2 acts both as a positive and negative cell death effector, depending upon cell lineage and stage of development.

Amyotrophic Lateral Sclerosis↗
PubMed1998

Determination of distances from tyrosine D to QA and chlorophyllZ in photosystem II studied by '2+1' pulsed EPR

A '2+1' pulse sequence electron spin echo (ESE) method was applied to measure the dipole interactions between the tyrosine YD+ and QA- in Photosystem II (PS II). In a CN--treated PS II, QA- EPR signal was observed at g=2.0045 position, because the non-heme Fe(II) was converted into a low-spin (S=0) state. The radical pair of YD+QA- was trapped by illumination for 8 min at 273 K, followed by dark adaptation for 3 min and freezing into 77 K. By using a proton matrix ENDOR, these trapped radicals were confirmed to be YD+ and QA-, respectively. The distance between the radical pair was estimated from the dipole interaction constant fitted to the observed '2+1' ESE time profile. The distance of YD+-QA- is determined to be 38.8+/-1.1 A. The magnetic dipole interaction between YD+ and ChlZ+ was determined in a Tris-treated PS II in which ChlZ+ was generated by illumination at 200 K for 10 min. The YD+-ChlZ+ distance was estimated to be 29.4+/-0.5 A. Copyright 1998 Elsevier Science B.V.

Journal Article↗
PubMed1998

Cytologic characteristics of parathyroid carcinoma: a case report.

A 44-yr-old man with a preoperative diagnosis of malignant mediastinal goiter underwent a preoperative fine-needle aspiration (FNA) biopsy. Fine-needle aspiration biopsy showed enlarged uniform nuclei, prominent nucleoli, few mitotic figures, karyolysis, anuclear cells, hyalinized nonepithelial cell clusters with hemosiderin deposits, and a perivascular pseudorosette pattern. This study reviewed the current literature dealing with this cytologic feature of parathyroid carcinoma. To our knowledge, this is the first report of an oxyphilic cell type of parathyroid carcinoma detected by FNA in the English-language literature.

Adenocarcinoma↗
PubMed1998

Accumulation of human T lymphotropic virus type I-infected T cells in the salivary glands of patients with human T lymphotropic virus type I-associated Sjögren's syndrome.

OBJECTIVE: To clarify the involvement of human T lymphotropic virus type I (HTLV-I) in the pathogenesis of Sjogren's syndrome (SS). METHODS: In HTLV-I-seropositive patients with SS, HTLV-I proviral DNA in the labial salivary glands (SG) was detected by polymerase chain reaction (PCR) amplification of the extracted cellular DNA, and the localization in the SG was examined by in situ PCR hybridization. RESULTS: The cellular DNA extracted from the SG contained full HTLV-I proviral DNA, which was present in the nucleus of the infiltrating T cells, but not in either the SG epithelial cells or the acinar cells. Furthermore, the viral loads in the SG were approximately 8 times to 9 x 10(3) times higher than those in the peripheral blood mononuclear cells. CONCLUSION: Accumulation of HTLV-I-infected T cells in the SG suggests that HTLV-I likely causes the self-reactive T cells to proliferate, which, as a result, induces SS.

Adult↗
PubMed1998

A single amino-acid substitution in gag p19 protein (MA) of Rous sarcoma virus suppresses virus production from infected cells.

Gag p19 protein (MA) of the transformation-defective Rous sarcoma virus mutant, tdPH2010, has a point mutation at nucleotide 376 (G to A) that results in an amino-acid change at residue 126 of p19 (Glu to Lys). This single amino-acid change is the cause of the aberrantly fast migration of this protein on SDS-polyacrylamide gels. To study the biological significance of the mutation, we introduced this mutation into a transformation-defective derivative of the molecularly cloned Rous sarcoma virus, SRA2, and examined its effect on virus replication. The virus possessing the mutation in its gag p19 gene had 50% slower replication as measured by the amount of reverse transcriptase as well as gag p27 protein (CA) in the culture media. Glu at position 126 appears to be important for efficient production of Rous sarcoma virus in vitro.

Amino Acid Substitution↗
PubMed1998

Dietary fructooligosaccharides prevent osteopenia after gastrectomy in rats.

Postgastrectomy osteopenia is observed generally in humans. Fructooligosaccharides increase the absorption of calcium from the large intestine of healthy rats. Thus, we have examined whether they stimulate calcium absorption and prevent osteopenia in rats following total gastrectomy. Rats were subjected to either a sham surgical operation or Billoth II gastrectomy. Seven rats from each surgical treatment group were fed a control diet, and another seven rats of each treatment group were fed a diet containing fructooligosaccharides (75 g/kg diet) for 4 wk. For 5 d each week, feces were collected, and the calcium and phosphorus contents were measured for calculation of the absorption of these minerals. At the end of the experiment, the rats were killed and bones were collected. The net calcium absorption, calcium content and bone mineral density of the femur and tibia in gastrectomized rats fed the control diet were significantly less than those in sham-operated rats fed control diet. The net calcium absorption in rats fed the fructooligosaccharides diet was greater than that in rats fed control diet. Moreover, dietary fructooligosaccharides prevented the decrease in the calcium content and bone mineral density in gastrectomized rats. Dietary fructooligosaccharides enhanced calcium absorption and prevented the changes indicative of postgastrectomy osteopenia such as decreases in bone calcium content and bone mineral density in gastrectomized rats.

Absorption↗
PubMed1998

Dietary fructooligosaccharides prevent postgastrectomy anemia and osteopenia in rats.

Gastrectomized rats develop anemia and osteopenia, and ingestion of fructooligosaccharides leads to an increase in iron absorption and promotes recovery from anemia in iron-deficient rats. Laparotomized (sham-operated control) rats and totally gastrectomized (Billoth II) rats, in groups of 14 each, were fed a control diet without fructooligosaccharides or a diet containing fructooligosaccharides (75 g/kg of diet) for 6 wk. All rats received an intramuscular injection of vitamin B-12 every 2 wk. Tail blood was collected every week for determination of hematocrit and hemoglobin concentration. At the end of the experiment, the rats were killed and the femur and tibia were collected for measurement of bone mineral density (BMD). The hematocrit, hemoglobin concentration, hemoglobin regeneration efficiency, and BMD of both femurs and tibias were significantly lower in gastrectomized rats fed the control diet than in the other three groups. Dietary fructooligosaccharides prevented anemia and osteopenia in totally gastrectomized rats.

Anemia↗
PubMed1998

Fermentation products of sugar-beet fiber by cecal bacteria lower plasma cholesterol concentration in rats.

Plasma cholesterol concentration is reduced by feeding some dietary fibers but the mechanism is not fully understood. We examined whether cecal fermentation products are involved in lowering plasma cholesterol by feeding rats a highly fermentable sugar-beet fiber (SBF) in four separate experiments. These were designed to investigate the effects on plasma cholesterol of oral ingestion of fermentation products on plasma cholesterol, the effects of the products in comparison with that of a short-chain fatty acid (SCFA) mixture, effects of individual SCFA and effects of alteration of energy and nitrogen ratio in the diet by the addition of the SCFA mixture. Cecal contents of rats were cultured with SBF by using a jar fermenter under anaerobic conditions, and the supernatant from the culture medium, containing fermentation products of SBF, was collected and freeze-dried before feeding to rats. Yield of fermentation products as dry weight from the fiber was 80-90%. In rats fed a diet containing fermentation products (80 g/kg diet), plasma cholesterol concentrations were lower than in rats of the fiber-free group 3, 7 and 14 d after feeding the test diet. Major SCFA in the fermentation products were sodium salts of acetic, propionic and butyric acids. Plasma cholesterol concentration in rats fed the diet containing a mixture of equal amounts of the three SCFA salts (66 g/kg diet) as the fermentation products diet was also lower than that in the fiber-free group and was not different from those in rats fed SBF (100 g/kg diet) and the fermentation products. In rats fed an acetate-containing diet but not in rats fed diets without acetate, plasma cholesterol was significantly lower than in the fiber-free group. In conclusion, absorption of SCFA from cecal fermentation products lowers plasma cholesterol. Acetate, and not propionate, may be responsible for lowering plasma cholesterol concentration.

Animals↗
PubMed1998

[Febrile episodes in elderly inpatients--a one year survey to determine the causes of fever in hospital].

To determine the cause of nosocomial infections, all febrile episodes of hospitalized elderly patients aged 65 and older at a hospital in Fukuoka City were categorized between April 15 1994 and April 14 1995. A febrile episode was a temperature above 37.5 degrees C after 7 consecutive days of normal body temperature (below 37.5 degrees C). Various clinical tests including blood examination, urinalysis, chest radiography and bacterial culture were done on the first and 7th day of the fever. A total of 1105 episodes in 443 patients (male 136, female 307) fulfilled this criteria for fever. The fevers were mainly due to respiratory tract (381 cases, 34.5%) and urinary tract infections (263 cases, 23.8%). There were 135 infections (12.2%) of other kinds and 297 cases (26.9%) that were classified as unknown. Approximately 70% of the febrile episodes were caused nosocomial infections, suggesting increased risk of infection in the hospitalized elderly and the importance of early detection of febrile changes in elderly inpatients.

Age Factors↗
PubMed1998

Contribution of the Pmra promoter to expression of genes in the Escherichia coli mra cluster of cell envelope biosynthesis and cell division genes.

Recently, a promoter for the essential gene ftsI, which encodes penicillin-binding protein 3 of Escherichia coli, was precisely localized 1.9 kb upstream from this gene, at the beginning of the mra cluster of cell division and cell envelope biosynthesis genes (H. Hara, S. Yasuda, K. Horiuchi, and J. T. Park, J. Bacteriol. 179:5802-5811, 1997). Disruption of this promoter (Pmra) on the chromosome and its replacement by the lac promoter (Pmra::Plac) led to isopropyl-beta-D-thiogalactopyranoside (IPTG)-dependent cells that lysed in the absence of inducer, a defect which was complemented only when the whole region from Pmra to ftsW, the fifth gene downstream from ftsI, was provided in trans on a plasmid. In the present work, the levels of various proteins involved in peptidoglycan synthesis and cell division were precisely determined in cells in which Pmra::Plac promoter expression was repressed or fully induced. It was confirmed that the Pmra promoter is required for expression of the first nine genes of the mra cluster: mraZ (orfC), mraW (orfB), ftsL (mraR), ftsI, murE, murF, mraY, murD, and ftsW. Interestingly, three- to sixfold-decreased levels of MurG and MurC enzymes were observed in uninduced Pmra::Plac cells. This was correlated with an accumulation of the nucleotide precursors UDP-N-acetylglucosamine and UDP-N-acetylmuramic acid, substrates of these enzymes, and with a depletion of the pool of UDP-N-acetylmuramyl pentapeptide, resulting in decreased cell wall peptidoglycan synthesis. Moreover, the expression of ftsZ, the penultimate gene from this cluster, was significantly reduced when Pmra expression was repressed. It was concluded that the transcription of the genes located downstream from ftsW in the mra cluster, from murG to ftsZ, is also mainly (but not exclusively) dependent on the Pmra promoter.

Cell Division↗
PubMed1998

Chicken (Gallus domesticus) inner ear afferents.

Neurons from the vestibular (VG) and the statoacoustic (SAG) ganglion of the chick (Gallus domesticus) were evaluated histologically and morphometrically. Embryos at stages 34 (E8 days), 39 (E13 days) and 44 (E18 days) were sacrificed and temporal bones microdissected. Specimens were embedded in JB-4 methacrylate plastic, and stained with a mixture of 0.2% toluidine blue (TB) and 0.1% basic Fuschin in 25% ethanol or with a mixture of 2% TB and 1% paraphenylenediamine (PDA) for axon and myelin measurement study. Images of the VIIIth nerve were produced by a V150 (R) color imaging system and the contour of 200-300 neuronal bodies (perikarya) was traced directly on a video screen with a mouse in real time. The cross-sectional area of VG perikarya was 67.29 micrometers2 at stage 34 (E8), 128.46 micrometers2 at stage 39 (E13) and 275.85 micrometers2 at stage 44 (E18). The cross-sectional area of SAG perikarya was 62.44 micrometers2 at stage 34 (E8), 102.05 micrometers2 at stage 39 (E13) and 165.02 micrometers2 at stage 44 (E18). A significant cross-sectional area increase of the VG perikarya between stage 39 (E13) and stage 44 (E18) was determined. We randomly measured the cross-sectional area of myelin and axoplasm of hatchling afferent nerves, and found a correspondence between axoplasmic and myelin cross-sectional area in the utricular, saccular and semicircular canal nerve branches of the nerve. The results suggest that the period between stage 34 (E8) and 39 (E13) is a critical period for afferent neuronal development. Physiological and behavioral vestibular properties of developing and maturing hatchlings may change accordingly. The results compliment previous work by other investigators and provide valuable anatomical measures useful to correlate physiological data obtained from stimulation of the whole nerve or its parts.

Animals↗
PubMed1998

2-(3-Pyridyl)thiazolidine-4-carboxamide derivatives. II. Structure-activity relationships and active configuration of 2-(3-pyridyl)thiazolidine-4-carboxamides as platelet-activating factor receptor antagonists.

Conversion of the 2-(3-pyridyl)thiazolidine part of 1-(3-phenylpropyl)-4-[2-(3-pyridyl)thiazolidine-4-carbonyl]piperazine (YM461), which is a potent platelet-activating factor (PAF) antagonist, to other rings was performed, and PAF antagonistic activities evaluated. The 2-(3-pyridyl)thiazolidine skeleton, which exists as a mixture of cis and trans diastereomers, played an important role in the potency of PAF antagonism. In this study, new effective skeletons were not uncovered, however, 2-(4-pyridyl)thiazolidine-4-carboxamides (1n and 1z) showed potent PAF antagonistic activities equal to the 3-pyridyl derivatives. From the results obtained for 1a, 1a(S), 1g and 1i, a cis-(2R,4R)-2-(3-pyridyl)thiazolidine-4-carboxamide was assumed to be the active configuration for PAF antagonism.

Animals↗