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Biomedical subjects

S Goto

Publications and source records attributed to S Goto.

At least 919 records · Page 51Linked to original sources
PubMed1986

Respiratory diseases in hard metal workers: an occupational hygiene study in a factory.

A hygiene study of a hard metal factory was conducted from 1981 to 1984. All workers exposed to hard metal were medically examined and their exposure to cobalt measured. Eighteen employees had occupational asthma related to exposure to hard metal, a prevalence rate of 5.6%. Nine had a positive bronchial provocation test to cobalt and reactions of the immediate, late, or dual type were elicited. Exposure measurements suggest that asthma may be caused by cobalt at a mean time weighted average concentration below 0.05 mg/m3. Only two of the nine individuals with cobalt asthma had a positive patch test to cobalt. Chest radiographs of three workers showed diffuse shadows of category 1 or over. X ray microanalysis of lung biopsy specimens from two of these three workers showed the presence of tungsten, titanium, cobalt, nickel, and some minerals. One of the two was diagnosed as having pneumoconiosis due to exposure to silica in a steel industry and the other was suspected of having pulmonary fibrosis caused by dust generated from the carborundum wheels used to grind hard metal. There were no cases with interstitial pneumonitis in the factory.

Adult↗
PubMed1986

Effect of hard metal dust on ventilatory function.

The effect of hard metal dust generated in shaping on ventilatory function has been studied, in particular, the relation between levels of exposure to cobalt and changes in ventilatory function. In 15 healthy young men a significant decrease in FVC occurred after a six hour exposure to hard metal dust containing cobalt at a mean concentration of 38 micrograms/m3 (range 14-76 micrograms/m3). No dose-effect relation could be discerned between the decrease in FVC and the hard metal concentration or the cobalt concentration. All the subjects complained of irritation of the airways. On the other hand, in 42 shaping workers exposed to cobalt at an average concentration of 85 micrograms/m3 no significant decreases in ventilatory function were detected after seven hour exposures to hard metal, although in 42 shapers, who had been exposed to cobalt at a mean concentration of 126 micrograms/m3, the FEV1% was significantly decreased compared with matched controls. This finding suggests that hard metal dust containing cobalt at a mean concentration of 126 micrograms/m3 causes chronic bronchial obstruction.

Adult↗
PubMed1986

Studies on vascular permeability increasing factors involved in 48-hour homologous PCA in the mouse ear.

Several attempts were made to elucidate the possible role of histamine, serotonin, leukotrienes C4 (LTC4) and D4 (LTD4), and prostaglandin E1 (PGE1) as vascular permeability increasing factors involved in 48-hour homologous passive cutaneous anaphylaxis (PCA) in the mouse ear. Increased vascular permeability in the mouse ear caused by the mediator injection or PCA was assessed quantitatively by measuring the amount of extravasated dye. In skin reactions, all of the mediators used in the present study significantly increased vascular permeability. The most potent mediator was serotonin, which increased the vascular permeability from a concentration of 10(-8) g/ml, and the activity was about 100 times higher than that of histamine on a weight basis. Vascular permeability increasing activity of LTC4 was about 10 times higher than that of histamine, and LTD4 and PGE1 were also more potent than histamine. Increases of vascular permeability caused by histamine, serotonin, LTC4 and LTD4 were significantly potentiated by injecting 10(-6) g/ml of PGE1 simultaneously. Histamine-, serotonin- and LTC4-induced skin reactions in the mouse ear were suppressed significantly by the administrations of chlorpheniramine, methysergide and FPL 55712, respectively. In contrast, though chlorpheniramine and methysergide suppressed also mouse ear PCA (about 50 and 40%, respectively), neither FPL 55712, indomethacin nor BW 755C suppressed it. These results strongly suggest that the most important mediator involved in mouse ear PCA is histamine and that serotonin also plays an important role in the increase of vascular permeability caused by PCA. Despite their potent vascular permeability increasing activity LTC4, LTD4 and PGE1 do not seem to play an important role in mouse ear PCA.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1986

Homologous passive cutaneous anaphylaxis in various strains of mice.

Passive cutaneous anaphylaxis (PCA) was elicited both in the ear and in the dorsal skin of 13 strains of mice at the same time and assessed quantitatively by measuring the amount of extravasated dye. Body pigments of colored mice such as DBA/2 (chocolate), C3H/He (brown) and C57BL/6 (black) did not interfere with the measurement of dye. In the ear response, ICR was a higher responder, C57BL/6 and BALB/c-nu/nu were lower responder strains. In the dorsal skin response, however, ICR was a lower responder, BALB/c-nu/nu, Hairless and WBB6F1-+/+ were higher responders. WBB6 F1-W/Wv was a nonresponder in both responses. The ear response was highly reproducible and the dorsal skin response of each strain was 1/2-1/10 of its ear response except for BALB/c-nu/nu. The PCA bluing regions on the dorsal skin of BALB/c-nu/nu were clearly delineated and the response was almost comparable to its ear response.

Animals↗
PubMed1986

Effects of various antibiotics on antibody-producing cells of mouse spleen.

The inhibitory effect of various beta-lactams on antibody production in the spleen was evaluated in mice immunized with sheep red blood cells by Cunningham's method. With a few exceptions, cephem derivatives were more effective than the penicillins tested in inhibiting the production of antibodies in the spleen of mice. This tendency was especially marked with cefsulodin, cefmenoxime, cefotiam and ceftazidime. However, no effect was obtained with 6-aminopenicillanic acid or 7-aminocephalosporanic acid. Our findings suggest that the difference among various beta-lactams in inhibitory effect on antibody production resulted from the difference in activities of beta-lactams with different side chains at the 6- or 7-positions.

Animals↗
PubMed1986

Pharmacokinetic and pharmacodynamic evaluation of gelatin microcapsule containing piretanide in beagle dogs.

A sustained-release property of gelatin microcapsules of piretanide was evaluated by pharmacodynamic parameters. The gelatin microcapsules of piretanide showed long-lasting, slow-release properties, when compared with its ordinary tablet form in the plasma piretanide level, piretanide excretion rate, urine excretion rate and urinary electrolyte (Na+, K+, Cl-) excretion rate without any loss in diuretic and saluretic activities, which fully satisfied the criteria for a sustained-release preparation.

Administration, Oral↗
PubMed1986

In vivo evaluation of ethyl cellulose microcapsules containing ampicillin using rabbits, beagle dogs and humans.

Ampicillin, an orally administered antibiotic, was microencapsulated with different viscosity grades of ethyl cellulose (10, 50 and 100 cps EC) and was orally administered to rabbits, beagle dogs and humans. A significant sustained release pattern was observed in rabbits. While a significant decrease in the area under the plasma concentration curve occurred, and the sustained release pattern was not obtained in beagle dogs. In humans, the extent of the sustained release was intermediate between the pattern observed in beagle dogs and rabbits. The treatment of data by log-log plots yielded a linear relation between half lives of dissolution of ampicillin from microcapsules in vitro (T50) and the ratios of pharmacokinetic parameters of microcapsules to those of powder. In order to explain the difference in the sustained release pattern of rabbits, beagle dogs and humans, a pharmacokinetic model, considering gastric-emptying and intestinal-transit rates of drug formulations, was established and the pharmacokinetic consideration was done on the basis of the model. It seems that success in sustained release of a drug depended on the magnitude of the gastric-emptying and intestinal-transit rate constant (kgi) of microcapsules, in the case of a drug with a small absorption rate constant (ka) as observed with ampicillin. The magnitude of kgi was thought to be in the order of beagle dogs, humans and finally rabbits.

Administration, Oral↗
PubMed1986

Effect of cinnarizine on IgE antibody mediated allergic reaction in mice and rats.

The effect of cinnarizine on immunoglobulin E (IgE) antibody mediated allergic reactions in mice and rats was investigated. Nifedipine and tranilast were used as comparative drugs. The dye leakage caused by IgE antibody mediated passive cutaneous anaphylaxis (PCA) in mouse ear was clearly inhibited by cinnarizine administered both orally and intraperitoneally. The inhibitory action of cinnarizine for PCA was as potent as nifedipine and superior to tranilast. Cinnarizine clearly inhibited the increase in capillary permeability caused by histamine and calcium ionophore A 23187 (A 23187) but not by LTD4 in mouse ear. Nifedipine inhibited the increases of capillary permeability caused by A 23187, histamine and LTD4. Tranilast inhibited A 23187 induced vasculitis but not histamine or LTD4-induced reaction. Cinnarizine had no significant effect on the release of histamine caused by antigen or A 23187 from rat peritoneal mast cells. Nifedipine and tranilast inhibited the release of histamine caused by both antigen and A 23187 from rat peritoneal mast cells.

Animals↗
PubMed1986

A new radioimmunoassay for human chorionic gonadotropin using monoclonal antibody.

A new radioimmunoassay (RIA) for human Chorionic Gonadotropin (hCG) was developed using murine monoclonal antibody to the beta-subunit of hCG (beta-hCG). The IgG fraction of the monoclonal antibody which did not react with 125I-beta-hCG was purified from hybridoma ascites, and covalently coupled to Sepharose 4B. This solid-phase antibody was incubated with standard hCG or serum sampled for 48 hours. The reaction medium was then removed by centrifugation and 125I-beta-hCG and anti-beta-hCG rabbit polyclonal antibody were added to the precipitate. The alcohol precipitation method was used for separating "bound" and "free" forms in the second reaction. The sensitivity for hCG in this assay system was 0.5 mIU/ml serum and the cross-reactivity with human Luteinizing Hormone (hLH) was 0.4%. This assay system was shown to be clinically applicable. Serial serum samples from two patients with trophoblastic disease were assayed and minute amounts of hCG, which could not be determined by conventional assay methods, could be assayed by this new RIA.

Adult↗
PubMed1986

Notochord action on spinal development. A histologic and morphometric investigation.

Forty-seven human embryos and fetuses of a gestational age from 5 to 13 weeks were studied histologically and histomorphometrically in an attempt to elucidate the possible action of the notochord on spinal development, in particular as it relates to segmentation. Segmentation occurred first in the tissue surrounding the notochord and not in the notochord itself; notochordal development at its most cranial part lagged behind that of its surrounding tissue. We also found that in later stages the decrease of notochordal cells at the level of the body was due to degeneration and not to migration of cells toward the intervertebral space. This observation puts into doubt the theory of squeezing or migration of notochordal cells from their vertebral position into the intervertebral disc space.

Body Height↗
PubMed1986

Notochord and spinal malformations.

Fourteen spinal malformations were found in 328 spontaneously aborted human embryos and fetuses. Of these, 13 were investigated histologically and histomorphometrically and compared with 47 age- and stagematched normal specimens to document any possible relationship between spinal and notochordal malformations. Although six notochordal malformations, such as bifurcation, were found in 14 spinal malformations, the respective sites did not correspond. Abnormality of notochordal tissue--such as degeneration and delayed development, which was observed in nine of 14 spinal malformations--was not restricted to the site of the spinal malformation. Moreover, tissue changes responsible for spinal malformations usually did not occur in direct contact with the notochord. On the other hand, malformed notochords were found in normal specimens. We therefore were unable to confirm in human specimens that notochordal abnormalities induce spinal malformations, a fact well established in lower vertebrates.

Embryo, Mammalian↗
PubMed1986

Synergism of cephalosporins at subinhibitory concentrations and polymorphonuclear leukocytes on phagocytic killing of Escherichia coli and its mode of action.

The interactions between subinhibitory concentrations of cephalosporins and polymorphonuclear leukocytes in the killing of a strain of Escherichia coli are described and an attempt is made to define the responsible mechanism. Ceftizoxime was the most potent agent tested. Pretreatment of the E. coli strain with subinhibitory concentrations of ceftizoxime increased the susceptibility to both; phagocytic killing activity of the polymorphonuclear leukocytes and bactericidal activities of the oxygen metabolites and the granule extracts. A most interesting result was the increased susceptibility of the ceftizoxime-treated E. coli to killing by beta-glucuronidase which normally is not bactericidal. It is suggested that the augmented killing could be due to bacteriolysis by beta-glucuronidase.

Animals↗