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H Hanai

Publications and source records attributed to H Hanai.

At least 19 recordsLinked to original sources
PubMed1996

Active fragments and analogs of the plant growth factor, phytosulfokine: structure-activity relationships.

Sulfated pentapeptide phytosulfokine-alpha (PSK-alpha) is the first chemically characterized peptidal plant growth factor that induces proliferation of the mesophyll cells of asparagus. To determine the active core involved in the sequence PSK-alpha, we synthesized PSK-alpha and twelve PSK-alpha analogs by the solid phase peptide synthesis and the direct sulfation to the peptide-resin using dimethylformamide-sulfurtrioxide (DMF-SO3) complex. The truncated analogs of PSK-alpha without the first and second C-terminal amino acids retained 8% and 20% of the activity of the parent pentapeptide, respectively. Deletion of the sulfate groups of Tyr1 and Tyr3 resulted in compounds with 0.6% and 4% of the activity of PSK-alpha, indicating that the sulfate group of Tyr1 is more important than that of Tyr3 for the expression of its activity. In contrast, the N-terminal truncated analog and unsulfated analog exhibited little or no activity. Thus the N-terminal tripeptide fragment H-Tyr(SO3H)-Ile-Tyr(SO3H)-OH has been identified as the active core of PSK-alpha.

Amino Acid Sequence↗
PubMed1996

Effects of aging on the microclimate pH of the rat jejunum.

The acidic microclimate layer in the vicinity of the cell surface of mammalian jejunum is important for absorption of some nutrients, such as small peptides and folate. The present study was undertaken to investigate the effect of aging on the cell surface pH (microclimate pH) of the jejunum of rats. The microclimate pH was measured in vitro in superfused preparations using single-barreled pH-sensitive microelectrodes filled with a liquid ion exchanger. The thickness of the microclimate layer was estimated by reading the distance of microelectrode advancements. The existence of a microclimate pH in the jejunum was confirmed in the senescent rats, but the value of the microclimate pH was significantly higher in the senescent (24 mo) rats (6.52 +/- 0.02) than in the young-adult (6 mo) rats (6.09 +/- 0.01) (P < 0.01). Na+ removal from the perfusate or the addition of amiloride elevated the pH in the senescent rats as well as in the young-adult rats. The microclimate layer was slightly thinner in the senescent rats than in the young-adult rats. The acidity of the microclimate layer of intestinal surface is lower in senescent animals than in the young-adult ones. One of reasons for this is the thinner mucus layer in senescent animals.

Aging↗
PubMed1996

Effects of aging on the regulation of intracellular pH in the rat jejunum.

Jejunal villus cells from young-adult (6 months) and senescent (24 months) male Wistar rats were studied to evaluate the effect of aging on intracellular pH (pHi) regulation. pHi was measured by quantitative fluorescence microscopy by using BCECF-AM [2',7'-bis(carboxyethyl)-5(6)-carboxy-fluorescein acetoxy methylester] under basal conditions and after inducing cytoplasmic acidification with pulsed NH4Cl. In the senescent rats, the recovery rate from the acidified levels was significantly lower than that in the young-adult rats (.208 +/- .005 vs .255 +/- .004 pH units/min). The relationship between pHi recovery and external Na+ concentration followed Michaelis-Menten type kinetics, the maximum velocity (Vmax) of alkalinization being significantly lower in the senescent rats than in the young-adult rats (.227 +/- .033 vs .297 +/- .024 pH units/min). These results indicate that the recovery of pHi from an acidic level was slower in the senescent rats, due to the reduced activity of Na+/H+ exchange as revealed by the decreased Vmax value.

Aging↗
PubMed1996

A very large villous adenoma with an adjacent cancer of the rectum: an informative case for testing the proposed molecular basis of colorectal tumorigenesis.

It is currently accepted that colorectal tumorigenesis results from accumulation of multiple mutations in certain genes. This concept prompted us to search for possible mutations in the APC, k-ras, and p53 genes in an advanced cancer coexisting with a large villous adenoma of the rectum in a 54-year-old patient with no family history of colorectal cancer. Genomic DNA extracted from multiple subregions of the tumor and surrounding normal mucosa was studied by polymerase chain reaction (PCR) followed by single-strand conformation polymorphism (SSCP) analysis and direct sequencing. Both the adenoma and carcinoma had abnormal PCR-SSCP for APC (exon 11) and k-ras, irrespective of the location within the tumors. However, p53 abnormality (exon 7) was detected only in samples taken from the carcinoma. Subsequent sequencing revealed a TTG to TAG mutation at codon 479 of APC, a GGT to GAT mutation at codon 12 of k-ras in both the adenoma and carcinoma, and a CGG to TGG mutation at codon 248 of p53 (exon 7) in the carcinoma. These findings were in accord with the current concept of colorectal tumor progression whereby genetic alteration of APC and k-ras occurs relatively early while that of p53 is rather late and is possibly a decisive event in relation to malignancy.

Adenoma, Villous↗
PubMed1996

[Current topics and endoscopic characteristics of the diagnosis how to detect in early gastric or colon cancer].

It is now an era of diversity of treatment for early cancer. Endoscopic diagnosis for both early gastric and colon cancer have focused on the detection of small or minute cancers(smaller than 5 mm), which could be resected by endoscopically. It has been generally considered that endoscopic curative treatment for the small cancer (smaller than 10 mm) is useful from the data of lymph node metastasis in early gastric cancer, however, a high incidence of recurrence (7.5 approximately 22.9%) after endoscopic mucosal resectomy has been found. High cancer rates and high rates of sm invasion are recognized in the superficial type, especially IIc, IIc + IIa, IIa + IIc, of colon tumor. The degree of invasion should be defined and a criteria for indication of endoscopic treatment should be determined from the endoscopic findings.

Colonic Neoplasms↗
PubMed1995

Factors affecting quality of ulcer healing after lansoprazole treatment.

To evaluate endogenous and exogenous factors affecting the quality of ulcer healing produced by proton pump inhibitors, gastric acid pH, serum gastrin, and serum pepsinogen (PG) I and II were measured in peptic ulcer patients before and after treatment with lansoprazole 30 mg once daily. Lansoprazole achieved more rapid scarring in duodenal ulcer (n = 34), with a healing rate of 97.1% after 6 weeks, than in gastric ulcer (n = 56), with a healing rate of 92.8% after 8 weeks. Scarring was the most rapid in gastroduodenal ulcer (n = 8), with a healing rate of 100% after 8 weeks, but the rate of complete scarring was the lowest (37.5%). Lower gastric acidity and lower PG I:II ratio were associated with poor quality ulcer scarring in patients with gastric ulcers, but the opposite was true for those with duodenal and gastroduodenal ulcers. For gastric ulcers, not only ulcer size but also mucosal atrophy was an important factor in ulcer healing. Smoking and alcohol consumption had little effect on the quality of ulcer healing during treatment. These results suggest that there are a number of differences between gastric ulcers and duodenal ulcers in terms of the quality of ulcer healing after lansoprazole treatment.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Effects of lansoprazole with or without amoxicillin on ulcer healing: relation to eradication of Helicobacter pylori.

We studied the effects of lansoprazole with or without amoxicillin on the quality of ulcer healing in relation to eradication of Helicobacter pylori. Ulcer healing rates for lansoprazole 30 mg q.d. alone (group A) were 100% for duodenal ulcers (DU; n = 20) and 92% for gastric ulcers (GU; n = 15). The healing rates for lansoprazole 30 mg plus amoxicillin 1-2 g q.d. (group B) were 100% for both DU (n = 20) and GU (n = 12). Endoscopic findings after treatment showed that the red scar/white scar ratio in group A was 16/4 for DU and 12/1 for GU. The red scar/white scar ratio in group B was 4/16 for DU and 6/6 for GU. The numbers of H. pylori in gastric mucus did not change throughout the course of treatment in group A but decreased significantly, without H. pylori relapse, in group B. Changes in ammonia concentration in gastric juice, as well as serum gastrin and pepsinogen I and II levels, differed between group A and group B. Concomitant treatment with lansoprazole and high-dose amoxicillin eradicated H. pylori and modified gastric secretory function, resulting in high-quality ulcer healing.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Multiple endocrine neoplasia type 1 accompanied by duodenal carcinoid tumors and hypergastrinemia: a familial case.

A 38-year-old female was admitted for investigation of the cause of hypergastrinemia, hypercalcemia and an elevated plasma parathyroid hormone (PTH) level. Her siblings, elder brother and sister who had duodenal carcinoid tumor with hypergastrinemia and parathyroid adenomas, were diagnosed as multiple endocrine neoplasia (MEN) type 1. In the present patient, endoscopic examination showed a carcinoid tumor of the duodenum, but examinations by computed tomography (CT) and ultrasonography of the abdomen failed to reveal pancreatic lesions. Serum gastrin levels of this patient and her siblings improved to the normal level after resection of carcinoid tumors. The hypergastrinemia accompanying MEN type 1 in these cases might be due to carcinoid tumor of the duodenum.

Adult↗
PubMed1995

Serotonin uptake and its modulation in rat jejunal enterocyte preparation.

In order to determine the properties of the intestinal serotonin (5-HT) transport system, we studied 5-HT uptake by villous cell preparations isolated from the rat jejunum. These enterocytes, probably heterogenous in cell population, accumulated 5-HT against concentration gradient up to a concentration 28 times that in the medium; this accumulation occurred in a temperature-dependent fashion. Most of the uptake was the result of a saturable process at low substrate concentrations. The saturable uptake was inhibited by 1 mM potassium cyanide or 1 mM ouabain or by substitution of other cations and sugars for Na+ in the medium. On the other hand, neither several amino acids nor putrescine had any effect on 5-HT uptake. Kinetic analysis yielded a Km value of 3.63 x 10(-7) M and a Vmax value of 5.76 pmol.10(6) cells-1.min-1 for this uptake process. Imipramine inhibited 5-HT uptake in a concentration-dependent fashion, with a Ki value of 3.66 x 10(-7) M. 5-HT uptake was also inhibited by ethyleneglycol-0,0'-bis(2-aminoethyl)-N,N,N',N'-tetraacetic acid, by verapamil, by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and by phorbol 12-myristate 13-acetate. These findings suggest that the present enterocyte preparation had a relatively specific secondary active transport system for 5-HT.

Animals↗
PubMed1994

[Cholera].

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Cholera↗
PubMed1994

[Cholera].

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Cholera↗
PubMed1993

Decrease in Gs protein expression may impair adenylate cyclase activation in old kidneys.

The possibility that alteration in stimulatory guanine nucleotide-binding protein (Gs) expression may contribute to the blunting of renal parathyroid hormone (PTH)-stimulated adenylate cyclase in aged rats was examined. Using rat cDNA probe, we identified a Gs alpha-subunit (Gs alpha) of 1.9 kb. Age did not alter the size of Gs alpha mRNA. The level of Gs alpha mRNA [normalized to poly(A)+ RNA] was decreased 23%, which was consistent with our previous report that Gs alpha protein decreased in senescence. In contrast, mRNA level of Gi alpha 2 increased with age. Level of beta-actin mRNA did not change with age. Nuclear runoff assay was performed to determine the transcription rate of Gs mRNA. Synthesis of poly(A)+ RNA and total RNA was reduced 39% and 37%, respectively, in nuclei prepared from old kidney, which suggested a general decline in RNA synthesis capacity in old rats. Our results also showed the transcription rate of Gs alpha mRNA in aged rats was reduced 89%, a decrease far exceeding that observed for total RNA or poly(A)+ RNA. We concluded that the decrease in steady-state level of Gs alpha mRNA was specific and probably was due to a reduction in the transcription activity. Thus alteration in Gs transcription may contribute, at least in part, to the impaired renal adenylate cyclase activation in aged rats.

Adenylyl Cyclases↗
PubMed1993

Decreased calcium pump activity in duodenal epithelial cells from spontaneously hypertensive rats.

Recently, hypertension research has focused on altered cytosolic free Ca2+, [Ca2+]i, in cells of spontaneously hypertensive rats (SHR). In this work, a mechanism(s) responsible for regulating [Ca2+]i was studied with duodenal epithelial cells isolated from SHR and their control, normotensive Wistar-Kyoto rats (WKY). The equal specific activity of sucrase, an enzyme characteristic of microvilli, in both mucosal scrapings and isolated cells from SHR and WKY suggested that mucosal density of enterocytes was not largely different between the two strains. [Ca2+]i of the isolated cells was estimated with fura-2. Upon incubation in the presence of CaCl2, [Ca2+]i increased to a larger extent in SHR than in WKY cells. Ca2+ efflux based on measurements of [Ca2+]i was decreased in SHR cells. Correspondingly, it was found that 45Ca efflux at 10 sec was lower for SHR cells than for WKY cells. Specific activities of Ca(2+)-stimulated and Ca2+/calmodulin-stimulated ATPases in basolateral plasma membrane preparations were reduced in SHR cells. These results indicated that Ca2+ efflux was decreased by reduction in Ca(2+)-pumping ATPase activity in SHR enterocytes.

Adenosine Triphosphatases↗