Acta Medica Okayama volume43 issue5

Chlorpyrifos, an organophosphorus insecticide, has been used to control termites since regulatory measures against the use of chlordanes were taken in September, 1986. We developed an improved gas chromatographic (GC) method for the assay of 3,5,6-trichloro-2-pyridinol (TCP) in the urine to use in the biological monitoring of exposure to chlorpyrifos. Urinary TCP was separated and determined accurately (C.V., 4%) with high sensitivity (detection limit, 10 ng/ml) and recovery (recovery greater than 90%) using a wide bore capillary column (WBC column). The accuracy and precision of the present GC method are satisfactory. The time course of urinary excretion of TCP was followed in workers. The urinary TCP level was low in the off-season and high in the busy season. Variation in the urinary TCP level corresponded to the termite control season and the length of the working period. The urinary TCP level showed a change reciprocal to the variations in the plasma cholinesterase activity. From these results, it is surmised that the urinary TCP level represents the extent of exposure to chlorpyrifos. The decrease in the level of cholinesterase activity is suggested to be due to exposure to chlorpyrifos. Determination of the urinary TCP level by GC using a WBC column is useful in the biological monitoring of chlorpyrifos in termite control workers and potentially has practical application to health care.

The rescue of infectious virus from nonproducer BH RSV(-) cells by chick cellular DNA was attempted in order to investigate the functional state of endogenous and exogenous retroviral genes integrated within the cellular DNA. No infectious virus was rescued by transfection with DNAs of chick helper factor (chf)-negative chick embryo cells (CEC), chf-positive CEC or uninfected CEC producing endogenous Rous associated virus (RAV-0). On the other hand, infectious Rous viruses with the phenotype of RAV-0 and RAV-1 were rescued by transfection with DNAs of CEC which had been infected with RAV-0 and RAV-1. From these results, it seems that exogenous retroviral genes integrated in the cellular DNA are expressed rather easily by transfection while those present endogenously are not.

To analyze the possible major T cell recognition site(s) of chironomid antigens, we established human T cell lines and clones (CD3+ 4+ 8-) reactive to soluble extracts of the adult midge of Tokunagayusurika akamusi (TAA) and/or Chironomus yoshimatsui (CYA). All T cell lines and clones proliferated heavily in response to relatively large molecular weight fractions of TAA (MW greater than or equal to 15,000). Nine clones reactive to TAA were classified into 3 groups according to reactivity, indicating the existence of at least 3 distinct T cell recognition sites in TAA. Five T cell clones responded to both TAA and CYA, although the two chironomid antigens were serologically distinct. We conclude that T cell recognition sites of chironomid antigens are different from B cell recognition sites in humans.

In order to clarify the origin of JC virus-induced brain tumors in rats, the development of tumors was sequentially analyzed histologically and immunohistochemically. Twenty-two of 30 rats (73%), which were intracerebrally inoculated with JC virus within 24 h of birth (group 1), developed, as a group, 45 brain tumors after 12 to 26 weeks. Seventeen of 27 rats (63%), which were inoculated on the 7th day after birth (group 2), developed 37 brain tumors as a group after a time 12 to 40 weeks. The tumors were found exclusively in the cerebrum. The microtumors, which were defined as tumors less than 2 mm in diameter, were located in the subependymal plate around the ventricular system. The microtumors and most part of the macrotumors consisted of cells of undifferentiated neuroectodermal nature, showing nuclear palisades and Homer-Wright-pseudorosette-like structures. Some tumor cells of macrotumors had an astrocytic nature and were positive for glial fibrillary acidic protein, S-100, Leu 7, and vimentin. In conclusion, the target cells of JC virus in rats may be undifferentiated subependymal cells of the cerebrum. The tumor cells show partial glial differentiation as they grow.

Excretion of sulfate and taurine, two major metabolites of sulfur, was examined in rats to study the nutritional status of sulfur metabolism in the mammals. Rats maintained on a conventional laboratory diet excreted 1.83 +/- 0.14 mmol of free sulfate and 229.0 +/- 75.3 mumol of taurine/kg of body weight per day. When the diet was changed to a synthetic 25% casein diet, the taurine excretion decreased to 15% of the previous daily excretion, but sulfate excretion decreased only slightly. These decreased levels returned to the original levels when 5 mmol of L-cysteine/kg of body weight was administered into the stomach through a catheter. One week after the first L-cysteine administration, when sulfate and taurine excretion had returned to the original levels, 5 mmol of L-cysteine/kg of body weight was administered likewise. The rats excreted sulfur corresponding to about 95% of L-cysteine administered in the form of free sulfate and taurine within a few days following L-cysteine administration, and sulfate excretion was 3.5 times more than taurine excretion. These results seem to suggest that, in rats, sulfur metabolism is in a state of equilibrium and that sulfate is formed preferentially to taurine.

A new volatile derivative of taurine, N-isobutoxycarbonyltaurine methyl ester (methyl 2-(N-isobutoxycarbonylamino)ethanesulfonate), was prepared by a three-step procedure for the gas chromatographic determination of taurine in urine. First, taurine was converted to its silver salt by reaction with silver oxide; next the silver salt was reacted with isobutyl chloroformate to form the N-isobutoxycarbonyl derivative, and finally the derivative was reacted with methyl iodide to form N-isobutoxycarbonyltaurine methyl ester. The volatile derivative was analyzed by gas chromatography using a column of 3% OV-101 on Chromosorb W. When methyl 3-(N-isobutoxycarbonylamino) propanesulfonate was used as an internal standard, the calibration curve was linear between 0.5 and 5.0 mumol of taurine/ml and showed a good reproducibility. This method was applied to the determination of taurine in human urine. Recovery was 98.6 +/- 5.2%, when 1.25 to 5.0 mumol/ml of taurine was added to human urine.

We report a case of unilateral hyperplasia of the adrenal medulla. The patient showed clinical features suggestive of pheochromocytoma. Removal of the hyperplastic adrenal gland resulted in complete disappearance of all prior symptoms, decrease of the plasma and urinary catecolamine levels and no high uptake in [133I] metaiodobenzylguanidine scintigraphy. A histological study revealed diffuse hyperplasia of the adrenal medulla. Up to now, there are relatively few reports of adrenal medullary hyperplasia in English literatures.

In order to improve the postoperative prognosis of gastric cancer patients we have performed preoperative endoscopic intratumoral administration of various biological response modifiers. In the present study we have investigated the kinetics and the immune response augmenting effect of intratumorally injected PSK, a protein-bound polysaccharide preparation, by immunohistochemical methods using anti-PSK antibody and various other antibodies. PSK-containing cells were located in the tumor tissues and follicular marginal zones of regional lymph nodes. Intratumorally administered PSK appeared to be phagocytized by the histiocytes and to cause them to become antigen-presenting cells. These cells may play a major role in augmenting immune responses in gastric cancer patients.