Time-resolved fluorometry of purple membrane of Halobacterium halobium. O640 and an O-like red-shifted intermediate Q.

The photocycle of the light-adapted purple membrane was studied with a time-resolved fluorometry apparatus: fluorescence of the sample suspension (greater than 660 nm) was pumped with a 633-nm cw laser and the temporal change induced by a 532-nm pulsed laser was measured with a photon-counting-type transient recorder. The formation and the decay of the O640 intermediate were clearly observed in the pH region between 4.0 and 11.4. A photochemical cycle of N560 was apparently driven in alkaline suspension (pH greater than 9.3). An O-like fluorescent intermediate Q appears and decays with time constants of less than 0.1 ms and 1.7 +/- 0.2 ms, respectively.

An experimental study on the long-term effect of cadmium in mice fed cadmium-polluted rice with special reference to the effect of repeated reproductive cycles.

Long-term biological effects of cadmium-polluted rice and the effect of repeated reproductive cycles on them were examined. Female SLC-B6D2F mice (female C57BL/6, male DBA/2) were fed a rice diet containing 65% unpolished rice for about 2 years from 7 weeks of age. The unpolished rice preparations used were commercially available rice (non-Cd-polluted) and Cd-polluted rice (over 1.0 ppm). Average Cd contents in each diet class were 0.12, 0.48, 1.78, 1.75, and 47.1 ppm (50 ppm Cd as CdCl2 added). Some experimental mice were subjected to repeated reproductive cycles (parity group). Hematological, biochemical, and pathological examinations of urine, blood, and tissues, including Cd measurement, were carried out. Results after statistical analysis indicate Cd toxicities such as anemia and disturbances of Ca metabolism. These Cd effects were found to be enhanced by the reproductive cycles. Soft X-ray radiograms showed osteoporosis in the parity groups, especially in the groups with diets of higher Cd content. However, we could not find any sign of disturbance of renal function under our experimental conditions.

An immunological study on patients with chronic cadmium disease.

Parameters of humoral and cellular immunity were investigated in patients with chronic cadmium (Cd) disease and compared to values in an age matched control group. In the patient group, there was a slight reduction in WBC although T and B lymphocyte ratios were normal. RBC counts were significantly reduced (P less than 0.05). No significant differences in serum immunoglobulin (Ig) concentrations were found. Blood Cd was significantly raised (P less than 0.001) and urine Cd was elevated. In lymphocyte transformation tests, responses to Staphylococcus aureus, PHA and PPD were not impaired and no evidence of Cd hypersensitivity was found. Responses in PHA and ADCC cytotoxicity tests were normal and nitro-blue tetrazolium (NBT) reduction was only slightly decreased in the patient group. beta 2-Microglobulin (beta 2M) was significantly raised in serum (P less than 0.001) and urine (P less than 0.001) of patients. Patient 3 day lymphocyte cultures produced significantly more beta 2M than cultures from the control group (P less than 0.01). beta 2M was increased in lymphocyte cultures, from patient and control groups, containing PHA (P less than 0.01), low Cd concentrations (P less than 0.01) or PPD. The results indicate that chronic Cd disease is not associated with significant alterations in immunological parameters in vitro. The high beta 2M levels associated with this disease may not result entirely from kidney damage but may in part be due to an increase in the release of beta 2M from cells, induced by Cd.