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Biomedical subjects

Y Orita

Publications and source records attributed to Y Orita.

At least 19 recordsLinked to original sources
PubMed1992

An experimental study on the treatment of hydrofluoric acid burns.

A 20% solution of hydrofluoric acid (HF) was applied to the skin of rats and a biomedical observation of the tissues and sera was made. Flushing with running water was effective for HF burns. By applying 2.5% calcium gluconate jelly, concentrations of fluoride in the urine and the tissues surrounding the injured region were reduced. Thus, the results proved that irrigation with running water and jelly applications were evaluated as the most effective therapy among various methods tested for HF burns.

Animals↗
PubMed1992

Serum fluoride as an indicator of occupational hydrofluoric acid exposure.

To define the relationship between ionic fluoride concentration in the serum of workers and the amount of hydrofluoric acid (HF) in the work environment, pre-and postshift serum and urine samples of 142 HF workers and 270 unexposed workers were examined. The maximum and minimum concentrations of HF in the air in each workshop varied from the mean by less than 30%. The preexposure levels of serum and urinary fluoride in HF workers were higher (P < 0.001) than the control values. This suggests that fluoride excretion from the body continues for at least 12h. The postshift serum and urinary fluoride concentrations of these workers were significantly higher (P < 0.001) than the preshift concentrations. A good correlation (r = 0.64) was obtained between postshift serum fluoride and postshift urine fluoride. There was a linear relationship between mean serum fluoride concentration and HF concentration in the workshop. A mean fluoride concentration of 82.3 micrograms/l with a lower fiducial limit (95%, P = 0.05) of 57.9 micrograms/l was estimated to correspond to an atmospheric HF concentration of 3 ppm. This is the maximum allowable environmental concentration recommended by the Japanese Association of Industrial Health, and it is also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results demonstrate that exposure to HF can be monitored by determining the serum fluoride concentration.

Adolescent↗
PubMed1992

Extended latissimus dorsi musculocutaneous flaps for extremely wide cervical skin defects involving the cervical esophagus.

Two cases using island distally and anteriorly extended latissimus dorsi musculocutaneous flaps for one-stage reconstruction of pharyngoesophageal defects of the entire front of the neck are reported. The advantage of this flap is its extremely large skin territory, which provides a reliable vascular supply. This flap is suitable for extremely wide cervical defects where the recipient vessels are damaged after severe infection and irradiation.

Aged↗
PubMed1992

Escherichia coli ATP synthase (F-ATPase): catalytic site and regulation of H+ translocation.

We discuss our recent results on the Escherichia coli F-ATPase, in particular its catalytic site in the beta subunit and regulation of H+ transport by the gamma subunit. Affinity labelling experiments suggest that beta Lys-155 in the glycine-rich sequence is near the gamma-phosphate moiety of ATP bound at the catalytic site. The enzyme loses activity upon introduction of missense mutations in beta Lys-155 or beta Thr-156 and changes catalytic properties upon introduction of other mutations. By analysis of mutations and their pseudo revertants, residues beta Ser-174, beta Glu-192 and beta Val-198 were found to be located near the glycine-rich sequence. The combined approaches of chemical labelling and genetics have been fruitful in visualizing the structure of the catalytic site. Analysis of mutations in the gamma subunit suggests that this subunit has an essential role in coupling catalysis with proton translocation.

Amino Acid Sequence↗
PubMed1992

[A case report of adenoid cystic carcinoma of the nasal septum].

A 50-year-old woman with adenoid cystic carcinoma of the nasal septum is presented. Her chief complaint was recurrent epistaxis. Surgery was originally performed to remove a nasal polyp, but during resection, the surgeon discovered that the mass had arisen from the nasal septum, so only a biopsy was done. The pathological report was adenoid cystic carcinoma, so she was referred and admitted to our hospital. A flat 1.5 x 1.5 cm tumor was recognized on the left side of the nasal septum. Nasal septectomy was performed. The tumor was dissected with nasal septal cartilage, and the defect was covered with a free skin flap from the thigh. The incidence of malignant tumors from the nasal septum is very low, composing from 2.7% to 8.4% of nasal and paranasal malignant tumors. Therefore the incidence of adenoid cystic carcinoma in particular is very low.

Carcinoma, Adenoid Cystic↗
PubMed1992

Pharmacological properties of the novel highly potent diuretic 7-chloro-2,3-dihydro-1-(2-methylbenzoyl)-4(1H)-quinolinone 4-oxime-O-sulfonic acid potassium salt.

7-Chloro-2,3-dihydro-1-(2-methylbenzoyl)-4(1H)-quinolinone 4-oxime-O-sulfonic acid potassium salt (M17055, CAS 114417-20-8) showed potent diuretic and saluretic effects dose-dependently, in rats (p.o.), mice (p.o.) and dogs (i.v.), at doses of 0.1-100 mg/kg, 0.3-100 mg/kg and 0.01-30 mg/kg, respectively. The efficacy of M17055 for diuresis, natriuresis and chloruresis was much higher than that of hydrochlorothiazide and almost the same as that of furosemide. These results indicate that this compound may be classified as a "high ceiling diuretic". The potencies of M17055 for natriuresis in rats (p.o.), mice (p.o.) and dogs (i.v.) calculated with ED50 values were 38, 34 and 24 times, respectively, more potent than those of furosemide. Urinary excretions of sodium, chloride and potassium increased in parallel with urinary volume with the administration of M17055 or furosemide, whereas an apparent dissociation with urinary calcium and sodium excretion was observed with M17055 alone. In rats, the increase of urinary calcium excretion with M17055 was significantly lower than that with furosemide under comparable conditions of natriuresis. Moreover, in mice, M17055 decreased urinary calcium excretion at doses with low effectiveness. In clearance studies using anesthetized dogs, M17055 suppressed negative free water clearance (CH2O) under saline loaded conditions, and it decreased positive CH2O under water diuretic conditions. These changes in the effects on CH2O induced by M17055 resemble those of loop diuretics. However, M17055 could not shift negative CH2O to positive, while furosemide was able to do so. Moreover, positive CH2O decreased to nearly zero with M17055, while urine remained dilute with furosemide even at 30 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

[Negative interference with peroxidase-coupled enzymatic serum creatinine assay by a hemostatic drug containing a hydroquinone structure].

We report a discrepancy between serum creatinine levels obtained by the method based on alkaline picric acid (Jaffé reaction) and that by automated analyzer employing enzymatic assay based on peroxidase-coupled reaction in a patient with renal dysfunction taking Ethamsylate, a capillary vessel stabilizer. Serum creatinine level obtained by the Jaffé reaction was 83 mg/l, and that by the enzymatic method was 22 mg/l. Recovery test of creatinine using the patient's serum showed 101 to 102% recovery by the Jaffé reaction and 77 to 89% by the enzymatic method. The same results were observed both in an in vitro test and in serum obtained from a healthy volunteer who had been given Ethamsylate previously. As the chemical structure of Ethamsylate includes a hydroquinone unit, it was thought that the compound may consume hydrogen peroxide produced by the reaction of peroxidase as the hydrogen donor and compete with the substrate used as the hydrogen donor for the color development. Thus evaluation of test results obtained by peroxidase coupled methods should be carefully interpreted in a patient who is consuming drugs which hydrogen peroxide such as hydroquinone.

Creatinine↗
PubMed1992

[Drug-induced acid-base disorders].

Drug-induced acid-base disorders may be classified into four categories with respect to the mechanism. 1. Metabolic acidosis is induced by a large acid loads incurred from exogenous sources (e.g. NH4Cl, or toxin ingestion) or endogenous acid production (e.g. generation of ketoacids or lactic acids by alcohol or phenformin) or base loss (e.g. abuse of laxatives). 2. Metabolic alkalosis results from exogenous bicarbonate loads (e.g. milk-alkali syndrome) or effective extracellular fluid contraction, potassium depletion plus hyperaldosteronism (e.g. vomiting, diuretics, or licorice). 3. Renal tubular acidosis is induced by the drugs which mainly impair proximal and/or distal tubules (e.g. vitamin D, NSAID, acetazolamide or amphotericin B). 4. Respiratory acidosis or alkalosis results from drug-induced respiratory center depression or neuromuscular impairment (e.g. anesthetic, sedative overdosage or curare) or hyperventilation (salicylates, paraldehyde, epinephrine, or nicotine).

Acid-Base Imbalance↗
PubMed1992

[Key note comment on the determination of glomerular filtration rate].

Glomerular filtration rate (GRF) is the most fundamental renal function. Determination of GFR is the most important examination in clinical nephrology. Cin is accepted as the gold standard of GFR, but, continuous infusion and the determination method of inulin (method of anthrone) are very troublesome. Interference of glucose in the serum and urine of patients with diabetes mellitus on the determination of inulin should be avoided. Ccr is widely used in the clinical field. Recently, the dynamics of creatinine in the body have been clarified. Variation of pool, generation rate, extrarenal excretion and tubular excretion of creatinine are found to change daily in the patient. Additionally, classical Jaffé's reaction involves non creatinine chromogen particularly in the serum. Though Jaffé's reaction with kinetic analysis improves the reliability of this reaction, the result is still unsatisfactory. There are several methods of enzyme assay are now using an autoanalyser, but, if we use many enzymes and reagents, the reliability of this method could not exceed that of Jaffé's method. Recently, HPLC is recommended as the standard method. 24-hr urine collection is also troublesome in the measurement of Ccr. I have found a good correlation between the estimated Ccr using Cockcroft and Gault's formula and Cin. Such prediction using serum creatinine concentration and few parameters should be developed. Radiolabelled agents have been widely used for the determination of GFR. However, in Japan, the methods of clearance of non radiolabelled contrast agents should be developed. Furthermore, a physical determination of GFR is necessary. In this workshop, these issues will be discussed by each speaker.

Animals↗
PubMed1992

[A method for the simultaneous determination of iothalamic acid and creatinine clearance by coupled-column liquid chromatography].

[125I]iothalamic acid clearance is used for the estimation of glomerular filtration rate. Therefore, we developed a coupled-column liquid chromatography for the simultaneous determination of iothalamic acid and creatinine in human serum and urine samples to calculate their clearance. The liquid chromatograph consisted of an automatic injector, four columns and four switching valves. Timing of sample injection and switching of valves were controlled by a combination of timer units. Diluted samples were injected into a column of weakly acidic ion exchanger (Asahipak ES-502C, 30 degrees C, C1), and iothalamic acid excluded from the column was purified by gel chromatography on a hydrophilic gel (Asahipak GS-320H, 50 degrees C, C2) and then by ion exchange chromatography on a weakly basic anion exchanger (Asahipak ES-502N, 50 degrees C, C3). Creatinine that was eluted from C1 after iothalamic acid was transferred to Asahipak GS-320H (37 degrees C, C4) and C1 was backflushed until 10 min before the next sample was injected. Samples were injected every 55 min. The mobile phase was a sodium propionate buffer prepared by dissolving 0.035 mol of NaOH and 0.35 mol of propionic acid in 1 kg of ultra pure water, and its flow rate was 1.1 ml per min. Creatinine clearance calculated from the data obtained by this method was higher than that obtained by Jaffé's method, because serum creatinine concentrations obtained by this method were lower than those obtained by Jaffé's method. Iothalamic acid clearance (y) calculated from the data on serum and urine samples of clearance time 105-135 min showed a close correlation with inulin clearance (x) calculated from the data obtained by the anthrone method, for which aliquots of the same samples were used (y = 1.066 x -1.429 ml/min, r = 0.997, n = 15).

Chromatography, Liquid↗
PubMed1992

[Clinical significance of urinary sediment dysmorphic red blood cells and casts in renal disease].

We investigated the utility of measuring dysmorphic red blood cells (d-RBC) and urinary casts in the diagnosis and assessment of prognosis of renal diseases by evaluating these parameters in a total of 278 urine specimens from 78 patients with various renal diseases at our hospital. Urinary sediments obtained by the conventional method with in 4 hours after voiding were subjected to Sternheimer and Malbin's staining and examined under a conventional light microscope. We used the criteria we previously devised for classification of RBC as d-RBC and for classification of casts hyaline, granular, epithelial, red blood cell, white blood cell, fatty, or waxy. When there were 5 or more urinary sediment red blood cells per high-power field, d-RBC was found in 94% of samples from patients with chronic glomerulonephritis. The finding of d-RBC was not related to glomerulonephritis pathologically diagnosed according to the WHO classification system for biopsy specimens. Even when there were fewer than 5 red blood cells per high-power field, d-RBC was sometimes found. Casts of all types were found in samples from patients with chronic glomerulonephritis or chronic renal failure. In samples from patients with chronic pyelonephritis, however, white blood cell, fatty, and waxy casts were not found, and less than 1 granular or epithelial cast per low-power field was found. The findings for the presence and the extent of both d-RBC and casts were in good accord with and changed with the clinical course, indicating that d-RBC and casts of urinary sediment can be used to predict the prognosis of patients with renal disease.

Adult↗
PubMed1991

Parathyroid hormone enhances gentamicin uptake by opossum kidney cells but not by LLC-PK1 cells.

Parathyroidectomy is proposed to be protective against gentamicin nephrotoxicity in rats. In the present study, we evaluated the effects of bovine PTH(1-34) on gentamicin accumulation in cultured kidney epithelial cell lines, opossum kidney (OK) cells which possess PTH receptors and LLC-PK1 cells which are devoid of PTH receptors. Ten days after seeding, the culture medium was exchanged for medium containing 1 mM gentamicin and bovine PTH. The cell gentamicin concentration was measured by a substrate-labeled fluorescence immunoassay (TDA gentamicin kit). Gentamicin uptake was accelerated by bovine PTH in OK cells but not in LLC-PK1 cells. The enhancing effect of bovine PTH seems to be mediated by a cAMP-dependent process. The results suggest that PTH accelerates gentamicin accumulation in renal tissues and potentiates gentamicin nephrotoxicity.

Animals↗
PubMed1991

Pharmacokinetics of denopamine in hemodialysis patients.

The pharmacokinetics of denopamine on a hemodialysis day and on an interdialysis day was evaluated in 11 hemodialysis patients. Tmax was the only pharmacokinetical parameter that differed significantly between healthy volunteers and hemodialysis patients. It is suggested that denopamine can be administered to hemodialysis both on hemodialysis days and on interdialysis days without dosage adjustments.

Adrenergic beta-Agonists↗