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Biomedical subjects

M Uchida

Publications and source records attributed to M Uchida.

At least 343 records · Page 19Linked to original sources
PubMed1989

Clinical pharmacology of N4-palmitoyl-1-beta-D-arabinofuranosylcytosine in patients with hematologic malignancies.

The pharmacokinetics of oral N4-palmitoyl-1-beta-D-arabinofuranosylcytosine (PLAC), a lipophilic and deaminase-resistant derivative of 1-beta-D-arabinofuranosylcytosine (ara-C), were determined in patients with hematologic malignancies. The concentration of ara-C and 1-beta-D-arabinofuranosyluracil (ara-U), metabolites of PLAC, were measured by radioimmunoassay and gas chromatography-mass spectrometry-mass fragmentography, respectively. The concentration of PLAC was determined by measuring ara-C, which was derived from PLAC by hydrolyzation. In six patients given an oral bolus of PLAC (300 mg/m2), the plasma-disappearance curve of PLAC corresponded to a one-compartment open model, including first-order absorption. The peak plasma level was 22.9 +/- 6.4 ng/ml, and the predicted time to reach the peak level was 2.5 +/- 1.0 h. The elimination half-life was 3.8 +/- 2.7 h. The plasma ara-C level increased slowly to 6.9 ng/ml during the 1st 2-3 h after administration and remained over 1.0 ng/ml for 12 h. Plasma ara-U was detectable for at least 24 h, with a peak concentration of 376 ng/ml at 6 h. Urinary PLAC excretion was below the limit of detection (5 ng/ml) in all cases. Prolonged urinary ara-C and ara-U excretion was detected, but the total recovery rate was low (6.7% in 24 h) and varied between patients. In spite of the lipophilic nature of the drug, the PLAC concentration in the cerebrospinal fluid, measured at 3 or 6 h, was below the limit of detection in all four patients with no meningeal involvement. This study showed low but persistent levels of PLAC in plasma and tissues, with a continuous release of small amounts of ara-C, which demonstrated antitumor activity in patients with hematologic malignancies.

Adult↗
PubMed1989

Molecular cloning and sequence analysis of duck hepatitis B virus genomes of a new variant isolated from Shanghai ducks.

The genomes of duck hepatitis B virus (DHBV) from a brown duck (S5) and a white duck (S31) kept independently in Shanghai, China, were cloned and the complete nucleotide sequence of each virion DNA (DHBV-S5 and DHBV-S31) was determined. DHBV-S5 and DHBV-S31 were both 3027 bp in length and 6 bp longer than the other two DHBVs analyzed previously, DHBV16 and DHBV3. The genomes of DHBV-S5 and DHBV-S31 encoded three long overlapping open reading frames designated as P, S, and C. A possible new open reading frame was found in a complementary strand of each viral genome, as 336 bp for DHBV-S5 and 306 bp for DHBV-S31, respectively. A pair of 3-bp insertions were found in the overlapping region of pre-S2 and P and so two amino acids were inserted in this region in DHBV-S5 and DHBV-S31. The nucleotide sequence variation between DHBV-S5 and DHBV-S31 (4.9%) was similar to that between DHBV16 and DHBV3 (5.6%), and less than the variations between either of these Shanghai clones and DHBV16 or DHBV3 (9.5-10.4%). The amino acid sequence was also conserved in the two Shanghai clones but showed group difference from DHBV16 or DHBV3. Thus these two independent Shanghai clones of DHBV showed geographical characteristics of genomic structure.

Amino Acid Sequence↗
PubMed1989

Model of electrocardiographic changes seen with subarachnoid hemorrhage in rabbits.

We developed a new method for introducing drugs into the basal cistern of rabbits. With minimal surgical invasion, we used either the opening of the craniopharyngeal duct to access the chiasmatic cistern or the suture between the basisphenoid and basioccipital bones to access the interpeduncular cistern. With our method, 0.5 ml contrast medium injected into three rabbits was determined roentgenographically to remain in the basal cistern; histologically, all the brain tissue remained intact. Intracisternal injection of 0.5 ml physiological saline into five rabbits had no effect on the cardiovascular system. In 23 rabbits, injection of 0.5 ml 0.1% prostaglandin F2 alpha led to a variety of electrocardiographic changes, including sinus bradycardia (in 43.5%), premature atrial contractions (in 17.4%), and premature ventricular contractions (in 39.1%). In 15 rabbits with severe changes, arrhythmia was followed by ST depression (in 30.4%), ST elevation (in 8.7%), T wave inversion (in 4.3%), ventricular tachycardia (in 17.4%), or ventricular fibrillation (in 4.3%). Intracisternal injection of 0.5 ml 1.0% lidocaine into the 23 rabbits was very effective in overcoming bradycardia and arrhythmias. We conclude that the clinical features of electrocardiographic changes seen in patients with subarachnoid hemorrhage are reproducible in this rabbit model.

Animals↗
PubMed1989

Studies on proton pump inhibitors. I. Synthesis of 8-[(2-benzimidazolyl)sulfinyl]-5,6,7,8-tetrahydroquinolines and related compounds.

Many 8-[(2-benzimidazolyl)sulfinyl]-5,6,7,8-tetrahydroquinolines were synthesized and examined for their (H+ + K+) adenosine triphosphatase ATPase-inhibitory and antisecretory activities. These sulfinyl compounds could be considered to be rigid analogues of the 2-[(2-pyridyl)methylsulfinyl]benzimidazole class of antisecretory agents. All the compounds tested were potent inhibitors of (H+ + K+)ATPase. Most of the compounds also inhibited histamine-induced gastric acid secretion in rats. Among them, 8-[(5-fluoro-2-benzimidazolyl)sulfinyl]-3-methyl-5,6,7,8-tetrahydroqu inoline (XIVm) was found to have the most potent activity. The structure-activity relationships are discussed.

Adenosine Triphosphatases↗
PubMed1989

Studies on proton pump inhibitors. II. Synthesis and antiulcer activity of 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinolines and related compounds.

Many 8-[(2-benzimidazolyl)sulfinylmethyl]-1,2,3,4-tetrahydroquinolin e derivatives were synthesized and tested for their (H+ + K+)adenosine triphosphatase (ATPase)-inhibitory and antisecretory activities against histamine-induced gastric acid secretion in rats. These sulfinyl compounds were synthesized by the oxidation of the corresponding sulfides, which were obtained from the reaction of 8-chloromethyl-1,2,3,4-tetrahydroquinolines and 2-mercaptobenzimidazoles in the presence of potassium carbonate. All compounds tested were potent inhibitors of (H+ + K+)ATPase. Most of the compounds showed antisecretory activity. Among them, 8-[(2-benzimidazolyl)sulfinylmethyl]-1-ethyl-1,2,3,4-tetrahydro quinoline (IXa) was found to have the most potent activity. The structure-activity relationships are discussed.

Adenosine Triphosphatases↗
PubMed1989

Studies on gastric antiulcer active agents. II. Synthesis of tetrazole alkanamides and related compounds.

A series of tetrazole alkanamides was synthesized and tested for antiulcer activity against acetic acid-induced gastric ulcer in rats. These compounds were prepared by the reaction of tetrazole alkanoic acids and various amines by the mixed anhydride method or acid chloride method. Among them, 3-[(1-ethyl-5-tetrazolyl)methylthio]propionamide (IIn) was found to have the most potent activity. The structure-activity relationships are discussed.

Animals↗
PubMed1989

Relapse of acetic acid-induced gastric ulcer and gastric mucosal prostaglandin I2 level in rats.

The healing process of acetic acid-induced gastric ulcer in rats was observed with an endoscope for 365 d after ulcer induction. The ulcers were induced by acetic acid solutions of various concentrations (2.5 (I), 5.0 (II), 10 (III) and 20% (IV); 0.05 ml). On day 3, a positive correlation was observed between the ulcer index (UI) and the concentration of acetic acid solution. On day 365, cumulative healing rates in groups I, II, III and IV amounted to 100, 100, 58.3 and 51.7%, respectively. The cumulative relapse rates in groups I, II, III and IV were 0, 13.6, 66.7 and 58.6%, respectively. Significant correlations were observed between initial UI values and cumulative healing or cumulative relapse rate. On day 365, rats were divided into two groups, a healed group and non-healed group, and the gastric mucosal prostaglandin I2 (PGI2) level was measured by bioassay. The PGI2 level around ulcers in ulcer-induced rats was higher than in normal rats, and it was higher in non-healed rats than in healed rats. Moreover, the PGI2 level was higher in those groups which showed a higher cumulative relapse rates. The above results indicated that the initial ulcer size and the PGI2 level around the ulcer might correlate to ulcer healing or exacerbation.

Acetates↗
PubMed1989

Studies on gastric antiulcer active agents. III. Synthesis of 1-substituted 4-(5-tetrazolyl)thio-1-butanones and related compounds.

Many 1-substituted 4-(5-tetrazolyl)thio-1-butanones were synthesized and tested for antiulcer activity against acetic acid-induced gastric ulcer in rats. These compounds were prepared by the reaction of 5-mercaptotetrazoles and 4-halogeno-1-butanones. Among them, 1-cyclohexyl-4-(1-phenyl-5-tetrazolyl)thio-1-butanone (VIIIp) was found to have the most potent activity. The structure-activity relationships are discussed.

Animals↗
PubMed1989

Healing process of acetic acid-induced gastric ulcer and gastric mucosal prostaglandin E generation level in rats.

The prostaglandin E (PGE) generation level (PGE level) in the gastric mucosa was investigated in relation to the healing and relapse of acetic acid-induced gastric ulcers in the rat. The PGE level around ulcers showed higher levels after ulcer induction and decreased during the ulcer diminishing period. Thereafter, the PGE levels showed an inclination to increase during the ulcer exacerbation period. In reulcerated rats, PGE levels were significantly higher. In conclusion, a high level of PGE may indicate an ulcer exacerbation state.

Acetates↗
PubMed1989

In vitro measurement of the pH gradient and thickness of the duodenal mucus gel layer in rats.

The mucus bicarbonate barrier of the duodenum has lately been reported to be one of the most important defensive factors for the duodenal mucosa. We established an in vitro system for evaluating the mucus bicarbonate barrier in the rat duodenum. Our method allows direct measurement of the pH gradient as well as the thickness of the mucus gel layer of the rat duodenum in vitro. The obtained results suggest that alkali secretion in response to acid-loading as well as the thickness of the duodenal mucus gel layer are greater than those in the stomach.

Animals↗
PubMed1989

Effect of the luminal hydrogen ion on alkali and mucus secretion in the rat stomach.

This study was designed to investigate the effect of luminal H+ on alkali and mucus secretion in the isolated rat stomach. At various luminal pHs, the thickness and the pH gradient of the mucus gel layer were measured. The maximum pH and calculated alkali secretion showed that the latter was stimulated in parallel with an increase in luminal H+ concentration, especially when the luminal pH became less than 3.5. Mucus secretion, however, was not significantly affected by the luminal H+ concentration. These results suggest that alkali and mucus secretion in the stomach are not regulated by the same mechanism, but different ones.

Alkalies↗
PubMed1989

Role of the mucus gel layer in the healing of acetic acid-induced gastric ulcers in rats.

Changes in the pH gradient and thickness of the mucus gel layer in the healing of acetic acid-induced gastric ulcers in rats were investigated. The maximum of the pH gradient and the thickness of mucus gel layer at the edge of ulcers and in the regenerated mucosa were higher, decreased gradually with the healing of the ulcers and finally reached normal values. This indicates that mucus and bicarbonate are secreted actively from the mucosa surrounding an ulcer and that they play an important role in protection of the base of ulcers and in acceleration of the healing of the ulcers.

Acetates↗
PubMed1989

[Case report of catecholamine-secreting carotid body tumor].

We encountered a case of catecholamine-secreting carotid body tumor which has never been reported in Japan. The patient was a 20-year old man, who complained of a mass located at the right neck and hypertensive symptoms such as loss of consciousness at extension of the neck, fatigability, etc. Carotid angiography and computed tomography (CT scan) revealed a carotid body tumor. Before operation, a mild hypertension was noted, serum and urinary levels of norepinephrine showed abnormal increase, and phentolamine test was positive. After the tumor was dissected by a surgical procedure associated with carotid reconstruction, blood pressure and norepinephrine levels clearly trended to decrease and phentolamine test returned to negative. Histopathologically, the tumor was a paraganglioma with so-called "organoid" pattern. The tumor was not chromaffin, but the presence of neurosecretory granules was confirmed under electron microscope. In one-year follow up after the operation, no sign suggestive of "latent" or newly arising paraganglioma was noted in assay of catecholamines in serum and urine, nor on adrenal CT scan.

Adult↗
PubMed1989

[Bacteriological investigation of the pre- and postoperative transition of the pharyngeal flora in the patients received tonsillectomy].

Several investigations have been reported on the interactive relation between the normal flora and the pathogenic micro-organisms in the human upper respiratory tracts (Thompson, Sanders, etc). It has also been known that some alpha-streptococci have inhibitory effect on the growth of group A beta-hemolytic streptococci. A study upon the role of alpha-streptococci in the throat (tonsil and pharynx) was performed using 73 culture specimens (throat swabs) obtained from 42 patients. Forty-four specimens were taken from the patients who received tonsillectomy, pre- and postoperatively, and 29 were from the patients who did not receive the operation. In the group of patients who received tonsillectomy, alpha-streptococci with inhibitory effect on the growth of group A beta-streptococci were detected less frequently preoperatively, when compared with the patients without tonsillectomy. On the other hand, postoperatively, marked increase of alpha-streptococci of these types was found in the normal flora of the throat. However, further detailed study on this subject is necessary because of the exceptional results in our observations.

Adolescent↗
PubMed1989

[Confined blasting in microexplosion cystolithotripsy].

This paper is the 12th report in a series of studies on the application of microexplosion to medicine and biology. Microexplosion lithotripsy is a newly developed technique in our clinic to crush urinary stones with small quantities of explosives. A systematic research project has been performed since the first report of microexplosion lithotripsy in 1977. As a result, microexplosion was successfully applied to the destruction of bladder stones in 130 cases from 1981 to 1988. In blasting to crush rocks in industrial works, two kinds of blasting are available: external charge blasting and confined blasting. The detonation power of the latter is 10 to 50 times larger than that of the former. A detruction test using several kinds of spherical form model calculus and lead azide explosive was performed. The formula to calculate the suitable explosive dose was determined experimentally as shown below. (formula; see text) Thus the theory in general industrial blasting with massive explosives was proved to be effective also in microexplosion with small explosives. An original electric drill system was developed to make a hole in stones for confined blasting. 60 cases, including 2 cases of giant bladder stones over 100 g in weight, were successfully treated by confined blasting using this system without any complication. We consider that any bladder stones, however big or however many, can be treated by microexplosion lithotripsy with confined blasting.

Adult↗
PubMed1989

HPLC quantitative analysis of plantaginin in Shazenso (Plantago asiatica L.) extracts and isolation of plantamajoside.

Quantitative analytical method by means of high-performance liquid chromatography (HPLC) has been developed for the quality control of Shazenso (Plantago asiatica L.) extracts. Plantaginin (I) which is one of the known constituents of Shazenso, was selected as a standard compound of the analysis. A chemically labile component has been isolated from the methanol extract and identified to be plantamajoside (II). It was found that II was converted into III even in hot water.

Chromatography, High Pressure Liquid↗
PubMed1989

[Osseointegrated implants in clinical dentistry. Surgical procedure].

Osseointegrated implant was developed by Professor Brånemark at the University of Göteborg, Sweden (1965). Implant are made from pure titanium (Ti 99.75%, others 0.25%), which are installed into the jaw bone using an osseointegrated method by leaving the fixtures unloaded and isolated for a period of 3 to 4 months in lower jaw bone and for a period of 5 to 6 months in upper jaw bone of totally edentuleus patients. The clinical procedure that produces osseointegration is performed in 2 major treatment stage due to being minimized tissue trauma. The fixture are fitted with a series of screw using abutment and prosthetic appliance. Osseointegrated implant placed within the 15 years of the study demonstrated a 91% success in the lower jaw and a 81% success in the upper jaw. We have experienced 30 clinical cases of osseointegrated implant since 1984 and then the clinical use of osseointegrated method give all our patients very satisfactory results. Pre-operative examination (including X-ray findings), surgical technique, clinical cases so on will be reported.

Bone Screws↗