Investigative & cell pathology最新文献

The structure of calcitonin in several species has been determined and its mode of action is now well established. The function of this hormone in man is still not completely understood but one role appears to be maintenance of the skeleton. It seems likely that future research in this field will be of great significance in understanding the mechanisms of disorders of skeletal metabolism.

Methods of measuring whole body protein turnover (WBPT) are discussed briefly. In a range of species from mouse to cow WBPT in the adult bears a fairly constant relationship to metabolic mass and to basal oxygen consumption. In young animals WBPT per unit metabolic mass is higher than in adults. During growth there appears to be an increase in the rate of protein breakdown as well as of synthesis. Of all tissues which have been studied, muscle shows the greatest developmental changes in the rate of protein synthesis. In the absence of food, for example during the night, the rate of protein turnover falls. Studies on the effects of different levels of protein and energy supply have not so far given a constant picture. Very few measurements of WBPT in disease states have been made. Preliminary results suggest that the loss of nitrogen after injury may be due to a block in synthesis rather than to an increase in body protein breakdown.

The potential inadequacies of current classifications of germ cell tumours are examined in the light of recent evidence high-lighting their high incidence of HCG and AFP production together with the responsible cell types.

A radioimmunoelectrophoretic method to detect alphafetoprotein in tissue sections of various germ cell tumours is described and its application in the field of oncological pathology is outlined.

The present functional and morphological studies strongly favour the concept that systemic immunosuppression with corticosteroids evokes differential, but not necessarily independent, lymph node and splenic responses.

The structure of bronchial carcinoids, oat cell carcinomas and pulmonary 'tumourlets' is described and evidence presented that they are related histogenetically, all being derived from certain specialized cells of endocrine or chemoreceptor nature found within the lining epithelium of the airways. Chemoreceptors related to pulmonary blood vessels have also been identified and two different types of pulmonary tumour have both been termed chemodectoma in the belief that they arise from such structures: these are the so-called multiple minute chemodectoma and the larger solitary variety but the exact histogenesis of both these tumours must remain conjectural at present.

Rat glomerular epithelial and mesangial cells, and rat skin fibroblasts, were cultured in RPMI medium containing 15% decomplemented fetal bovine serum. They were incubated for 1 h at 37 degrees C with 2 mM [Ca2+]. At that time, their response to various concentrations of angiotensin II, norepinephrine and carbamylcholine was studied by phase contrast microscopy. Only the mesangial cells exhibited contractile activity in the presence of 10(-10) M angiotensin II and 10(-6) M norepinephrine, as demonstrated by the reduction of their length or, more frequently, by modification of their shape. No contractile activity was observed in the presence of 10(-5) M carbamylcholine. The percentage of contractile cells increased proportionally to the concentration of angiotensin II, reaching about 35% with 10(-6) M angiotensin II. The contractile activity was reversible. Specific inhibitors, i.e. Sar1-ala8-angiotensin II and phenoxybenzamine, when administered in concentrations 10 to 100-fold higher than that of the corresponding agonists, completely blocked the contractile response. This competitive effect was also reversible. The data, therefore, suggest that mesangial cells in culture display some functional properties of smooth muscle cells.

Low doses of inorganic mercury may cause an immune complex glomerulopathy in man and in experimental animals. In the PVG/C rat this mercury-induced glomerulopathy coincides with the occurrence of anti-nuclear antibodies in the serum. The same anti-nuclear activity can be demonstrated in the acid-eluted glomerular immune deposits. The characterization of the pathogenic nuclear antigen, to which these antibodies are induced, is the subject of this study. The effect of acid, fixatives, nucleases and proteases on indirect immunofluorescence of anti-nuclear antisera and IgG purified from these sera is studied, combined with absorption with several nuclear constituents and specific antigen blocking by Concanavalin A. The results show that the nuclear antigen involved is part of the nonhistone chromatin protein fraction.