We studied 438 persons who were engaged in the production and use of aromatic amines (benzidine sulfate, β-naphthylamine, α-naphthylamine and dianisidine). Among these 438 persons, 88 new cases of occupational uroepithelial cancer had occurred from 1949 to 1995. The incident rate of occupational uroepithelial cancer was 20.1%. The average exposure period of these 88 cases to the aromatic amines was 7.40 years (range, 0.75-26.75), and the incidence rate of tumors increased with the length of exposure to aromatic amines. The average latent period was 26.79 years (range, 1.33-48.50), and the average age of first onset was 52.59 (range, 24-79). Recently it has been determined that the longer the latent period, the older the age of first onset. Of these 88 cases, the tumor sites were bladder in 67 cases (76.1%) and upper urinary tract (renal pelvis and/or ureter) in 5 cases (5.7%). The other 16 cases (18.2%) were the bladder and upper urinary tract. The screening examination for chemical workers using urinary cytology was begun in 1962. In our cases, urine cytology was a useful method for diagnosing occupational uroepithelial cancer. As for initial treatment of the 88 cases, transurethral surgery was most frequently performed, that is on 58 cases (65.9%). However, eight cases (9.1%) had to undergo a total nephroureterectomy, and six cases (6.8%) had a total cystectomy. Recurrence was observed in 61 cases (69.3%) out of the 88 patients with an average of 1.81 times. The other organic cancers developed in 39 cases (8.9%) out of 438 workers who were exposed to aromatic amines and in 8 cases out of 88 patients (9.1%). Prognosis of the 88 patients is that, the number of alive and dead is 51 (58.0%) and 37 (42.0%) respectively on December 31, 1995. Twenty-eight patients (31.8%) died of uroepithelial cancer, and five patients (5.7%) died of other organic cancers. The survival rates of 5, 10, 15 and 20 years was 87.9%, 74.0%, 65.9% and 56.3%, respectively. From these results, patients with occupational uroepithelial cancer and workers who are exposed to aromatic amines should undergo long term observation.

View full abstract

Brain-derived neurotrophic factor (BDNF) is produced in Schwann cells and fibroblasts in the peripheral nerve, and is considered to play an important role in survival, maintenance, development and repair of the peripheral neuron. In this study, the effect of human recombinant BDNF on the regeneration of nerve fibers following a crush injury to the sciatic nerves of Sprague-Dawley rats was evaluated. In the experimental group, 20 mg/kg of BDNF was injected subcutaneously three times a week for 4 weeks in seven rats. In the control group, only the dissolving solution used in the experimental group was injected similarly in seven rats as in the experimental group. The various morphometric parameters were evaluated in the peroneal, sural and tibial nerves and the nerve to soleus muscle distal to the crush site. There were no statistically significant differences in the change of body weight, the improvement of the width between the first and fifth toes on the side of the crush, the density of total myelinated fibers (numbers per mm²), the total number of myelinated fibers (number per nerve), maximum and median diameters of myelinated fibers, the density of unmyelinated fibers, and the electron microscopic parameters of axon and myelin sheath. On the other hand, the number of myelin lamellae in relation to the transverse axonal area was significantly greater in the experimental group than in the control group. Therefore, BDNF may promote the myelination. However, such an effect on myelination seems not to be clinically significant, because such an effect was not demonstrated in other morphometric evaluations reflecting the myelination condition. Therefore, taking all the data obtained in this study into consideration, we concluded that there was no definite evidence that BDNF promoted the regeneration of nerve fibers at least under these experimental conditions.

View full abstract

The aim of this study is to evaluate the air pollution due to smoking in an office where no smoking control measures have been adopted. The concentration of suspended particulates (SP) at 8 points in this office were measured and the change of SP concentrations at 3 points were recorded for 24 hours. The results show that the main source of SP is tobacco smoke in the office. Smoking control measures should be promoted in such offices where smokers and non-smokers work together. The effectiveness of a ventilation system and practical smoking control measures are discussed.

View full abstract

To study the role of endothelial cells in important biological phenomena such as thrombosis and atherosclerosis, it is necessary to have a sufficient amount of endothelial cells. This report shows modified methods to isolate endothelial cells from the human unbilical vein and the components of potent and low-cost culture medium for the cells.

View full abstract

Papers listed in the Index Medicus (1974-95) concerning 9 chemicals (lead, styrene, toluene, trichloroethylene, tetrachloroethylene, dimethylformaldehyde, trichloroethane, xylene and hexanes) designated by Japanese law to be monitored biologically were examined. Papers on lead outnumbered those on the other chemicals, probably reflecting the importance of lead intoxication throughout the world. Papers on toluene have been second to those on lead for the past 15 years. The materials collected in this search may provide the basis for further study of the literature on biological monitoring.

View full abstract