A role for airborne particulates in high mercury levels of some cetaceans.

In a study of 25 Tursiops truncatus and two Globicephala macrorhynchus examined by necropsy, abundant HgSe was found in both the liver and in the respiratory system (lung and hilar lymph nodes). In the liver HgSe was consistently associated with the cell-breakdown pigment lipofuscin, whereas in lung and hilar lymph nodes it was consistently associated with particulates consisting of partially graphitic soot and silicates. This supports earlier suggestions that in the liver HgSe may be a storage end product of Hg metabolism, while adding the new suggestion that in the respiratory system HgSe may be inhaled, preformed in combustion emissions.

Liver abnormalities associated with chronic mercury accumulation in stranded Atlantic bottlenose dolphins.

Eighteen stranded Atlantic bottlenose dolphins (Tursiops truncatus) examined postmortem were sampled for histologic study. All cases were examined for ferric ion and lipofuscin. Ages were determined from tooth growth layers. Electron microscopic (EM) examination and X-ray spectroscopy (EDAX) were performed. Chemical analysis for mercury was conducted on 12 of the animals by atomic absorption spectrophotometry. Nine animals were found to have excessive lipofuscin in both liver and kidney. Four of these nine animals also exhibited active liver disease (fat globules, central necrosis, lymphocytic infiltrates) whereas, of the animals without the excessive pigment, only one animal had an active liver lesion. EM and EDAX showed electron-dense amorphous material presumably within lysosomes to be Hg with no deposits on mitochondrial or nuclear membranes noted. Age relationship to portal pigment deposition was positive. Liver mercury concentrations ranged from 0.01 to 443 micrograms/g of wet weight with all animals having liver pigment yielding values of or above 61 micrograms/g, whereas all animals lacking pigment had values of or below 50 micrograms/g. The evidence suggests that the excessive pigment accumulation is related to toxic effects of Hg and presents as increased active liver disease.

Lymphangiomyomatosis in the Atlantic bottlenose dolphin (Tursiops truncatus).

The first case of lymphangiomyomatosis in a marine mammal is reported from a stranded male Atlantic bottlenose dolphin (Tursiops truncatus). This progressive proliferative disease involved the lungs and the mediastinal and probably mesenteric lymph nodes. An extraordinarily low level of testosterone may have been pathologically significant since all reported cases of this disease in humans occur in females.

Lymphocyte populations in rheumatoid arthritis.

For each of 28 patients with RA and 27 normal controls, the in vitro lymphocyte responses to PHA and to Con A were simultaneously determined on aliquots of the same cell preparation. In the case of RA lymphocytes, the response to Con A was abnormally low when compared with the simultaneous response to PHA (P less than 0.01). Cells capable of responding to PHA were specifically killed with BUdR. The cells remaining after this procedure showed a relatively greater response to Con A than did the original population. In the case of RA lymphocytes, this relative increase in the response to Con A was significantly less than normal (0.02 greater than P greater than 0.01). These results suggest that a lymphocyte subpopulation, responding principally to Con A, is relatively reduced in RA.

Abnormalities of peripheral blood lymphocytes in rheumatoid arthritis.

Peripheral blood lymphocytes from some rheumatoid arthritis (RA) patients show a reduced response to PHA when stimulated directly after isolation from blood. Cells which have been preincubated in medium with normal serum for 22 h before exposure to PHA show a relatively enhanced response, which approximates the normal. These findings could be compatible either with the blocking of surface PHA receptors of circulating RA lymphocytes, or with progressive maturation of these cells in vitro. Preincubation does not enhance the relatively reduced response of RA lymphocytes to allogeneic RA lymphocytes in one-way mixed lymphocyte cultures. An increased reduction in response to PHA following irradiation of RA lymphocytes suggests an increased radiosensitivity of the PHA-responsive subpopulation. This abnormally reduced response was not seen if the cells were preincubated in vitro prior to irradiation.