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Biomedical subjects

T Tozawa

Publications and source records attributed to T Tozawa.

At least 37 records · Page 2Linked to original sources
PubMed1987

Basal cell carcinoma with follicular differentiation.

A distinctive form of basal cell carcinoma with follicular differentiation was studied in 15 biopsy specimens. The neoplasms differ from other variants of basal cell carcinoma by being situated on the face only, being small and well circumscribed, and having signs of follicular differentiation, namely, numerous tiny infundibular cyst-like structures and aggregations of neoplastic cells that resemble hair follicles in telogen. The diagnostic features of basal cell carcinomas with follicular differentiation are enumerated and illustrated.

Adenocarcinoma↗
PubMed1985

[Urinary excretion of cadmium, copper and zinc in workers exposed to cadmium].

Changes in urinary cadmium, copper and zinc excretion in workers who had considerable exposure to cadmium oxide fumes were investigated over a 5-year period following the cessation of exposure. The 22 male subjects aged 22 to 55 had been welders on automobile parts for periods ranging from 7 months to 23 years, using silver solder which contained cadmium. They were divided into three groups according to levels of urinary cadmium in the first medical examination in 1975: 5 in the high excretion group, 11 in the moderate group, and 6 in the low group. Renal tubular dysfunctions were indicated in most workers in the high excretion group but not in the other two groups. The high and moderate groups showed a rapid decrease in the levels of urinary-excreted cadmium, with biological half-times of 1.42 and 1.21 years, respectively. Excreted cadmium levelled off in the two groups about 1.7 and 1.5 years after the last exposure. Urinary copper excretion in the high cadmium excretion group was about twice that in the moderate and low groups, the difference being statistically significant in comparison with the controls. Urinary zinc excretion was high in all subjects immediately after cessation of exposure but decreased rapidly. After three years it was found that the reduction of urinary zinc was greatest in the high cadmium group. Urinary cadmium showed significant correlations with both copper and zinc. Urinary copper showed a negative correlation with zinc excretion in the high cadmium excretion group and a significant positive correlation in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1981

[Experimental pneumoconiosis induced by cemented tungsten and sequential concentrations of cobalt and tungsten in the lungs of the rat (author's transl)].

Experimental pneumoconiosis was induced by intratracheal injection of dusts of presintered cemented tungsten carbide, G2 (WC : Co=98 : 2) and TX20 (WC : Co : TiC : TaC=64 : 16 : 6 : 14) into the lungs of rats in order to document the pathological changes in lung tissues associated with environmental cobalt and tungsten. The following results were obtained. 1) Six months after the administration of G2 and TX20 dusts, marked fibrotic foci were noted and tungsten was detected in the lung tissues of all of the experimental animals. 2) Twelve months after the administration of both dusts, both the fibrotic changes and the tungsten levels were reduced in both test groups, but the reduction was more notable in the G2 group. The cases with fibrotic changes were relatively concomitant with the cases in which tungsten was detected. 3) On examination of tissue levels of cobalt derived from the dust, the cobalt levels in the lungs and bone tissues were less influenced by the dust of the G2 group at any point of investigation, whereas only the pulmonary cobalt levels at six months after the administration of the TX20 group showed a remarkable influence from the dust cobalt (p less than 0.01). 4) In the cases where tungsten was detected six months after the administration of both groups and twelve months after the administration of the TX20 group, pulmonary cobalt levels had not reached the value that should have been gained by the addition of expected values (dust cobalt levels calculated from the tungsten levels) to the control values. 5) The above results indicate that both G2 and TX20 dusts induced marked fibrotic changes in rat pulmonary tissues. However, these changes were reversible to some extent. In addition, a portion of the dust cobalt was dissolved in the body fluid and disappeared from the pulmonary fields.

Animals↗
PubMed1981

[Pulmonary functions observed by means of flow-volume curve in welders exposed to ozone (author's transl)].

Pulmonary functions were observed by the flow-volume curve method on 68 healthy welders who had been exposed to comparatively high levels of ozone while engaged in arc welding process shielded by inert gas. The welders between 20 and 29 years of age were selected as subjects and classified into five groups according to ozone concentrations of the workshops. Results of pulmonary function tests were analyzed with reference to working experiences, dust concentrations of the workshops, smoking habits and air pollution levels of the location of factories. An attempt were made to evaluate the possible effects of prolonged exposure to ozone produced by welding upon the health or workers. The results obtained were as follows. 1. Values of both peak flow rate and maximum expiratory flow rate at 75% of vital capacity (V75) were decreased slightly in welder groups, but relationships between the observed values and ozone concentrations were not recognized. 2. Values of maximum expiratory flow rate at 25% of vital capacity (V25) of welders who had been exposed to ozone in concentration of 1.05 ppm or more were decreased significantly compared with groups exposed to ozone under 1.05 ppm. 3. In addition, values of both V25 and forced vital capacity (FVC) of the workers who had been engaged in welding for 4 years or more were significantly lower than those of the workers for less than 4 years of exposure. However, the relationship between the lung function values and smoking habits were not significant in both groups. 4. The decreases in V25 values were observed in several workers who had been exposed even to 0.46 ppm or higher (but under 1.05 ppm) ozone concentrations. 5. Relationships between the lung function values and either smoking habits or air pollutant levels of locations were not significant in all groups.

Adult↗
PubMed1980

Effects of cemented tungsten carbide dust on rat lungs following intratracheal injection of saline suspension.

In order to examine the effect of cemented tungsten carbide dust on the animal lung, saline suspensions were intratracheally administered into the lungs of rats in a single dosage. About one-fifth of the animals died during the first three days. The acute response of the lungs was hemorrhagic edema with intense alveolar congestion. The animals killed at six months all presented pulmonary lesions of patchy fibrosis in the vicinity of the deposited dusts, occasionally associated with focal traction emphysema and bronchobronchiolar ectasia. At twelve months, two-third of the animals had neither fibrosis nor dust deposition, although the remaining animals showed pulmonary lesions similar to those seen in the six-months responders. Fibrosis of the lungs seemed to consist of collapsed alveoli with condensation of the preexistent reticulin fibers, but without noticeable collagenization. It is supposed that both the early toxic and the late fibrogenic effects of the carbide dust are attributable to the cytotoxic action of cobalt present in the dust particles. It is possible that recovery of the pulmonary lesions results from removal of the dusts from the lesions.

Animals↗
PubMed1978

Cemented tungsten carbide pneumoconiosis.

An autopsy case of cemented tungsten carbide pneumoconiosis, the first lethal case in our country, is presented. A 28-year-old woman, who had been engaged in grinding presintered metallic matrix for four years, developed respiratory symptoms. X-ray examinations were indicative of interstitial pulmonary fibrosis. Corticosteroid therapy revealed only little effect. She expired five years after the onset of the symptoms. Postmortem examination showed nonspecific interstitial pneumonitis resulting in marked lung fibrosis. Ultrastructurally, crystals were observed in cytoplasm of presumable macrophages in the fibrotic lung tissue. Electron probe microanalysis of the lung tissue showed the presence of tungsten and other constituents of tungsten carbide except for cobalt. Metal analysis demonstrated a large amount of tungsten in the lung. Cobalt was detected tenfold of the normal value in the bone. In pathogenesis of the pneumoconiosis in the cemented tungsten carbide workers, toxicity of cobalt is most suspectable, and in addition, individual susceptibility may be also important.

Adult↗