Micropolyspora faeni causes airway inflammation but not hyperresponsiveness in sensitized ponies

We assessed the effect of aerosol Micropolyspora faeni challenge in two groups of ponies by measuring lung function, airway reactivity to aerosol histamine, and bronchoalveolar lavage fluid cytology. One group of ponies was sensitized by subcutaneous injection of M. faeni in complete Freund's adjuvant, and the other group served as control. In both groups of ponies, measurements were made at base line and 5 h after aerosol administration of 30 ml of saline or 30 ml of 1% wt/vol particulate M. faeni antigen in saline. Saline challenge had no effect on any of the measured variables. M. faeni challenge had no effect on pulmonary mechanics or gas exchange in the control group but significantly increased respiratory frequency and minute ventilation and decreased arterial CO2 tension in the sensitized ponies. In both groups of ponies, aerosol M. faeni challenge significantly increased total white blood cell count and neutrophil numbers in bronchoalveolar lavage fluid while large mononuclear cell numbers decreased. Airway responsiveness was unaltered by saline or M. faeni challenge in both pony groups. We conclude that aerosol M. faeni challenge induces pulmonary neutrophilia and abnormalities of ventilation but is not accompanied by airway hyperresponsiveness in sensitized ponies.

The azurocyte: a new kind of leukocyte from wild voles (Microtus)

We have identified a new mammalian leukocyte from voles (Cricetidae, Microtus). This "azurocyte" is a large mononuclear cell with numerous cytoplasmic inclusions that stain purple with azure dyes. The cell resembles a young lymphocyte with numerous mitochondria, a prominent Golgi complex, and modest amounts of rough endoplasmic reticulum. The inclusions are homogeneous, membrane-bound, electron-dense bodies that contain a highly acidic, sulphated glycosaminoglycan, glycoprotein, nonspecific esterase, β-glucuronidase, and an aminopeptidase. Azurocytes are common in adult voles, particularly pregnant females, and can be induced artificially with progesterone. In humans (large granular lymphocyte) and in guinea pigs (Kurloff cell), morphologically distinct cells with azurophilic inclusions have been associated with natural killer activity. The vole azurocyte may therefore be a similar leukocyte with special functions during pregnancy.

Histochemical study of mesenteric lymph nodes in old rats

The main positive reactions in the large mononuclear cell occurring in some nodes were shown with PAS, alcian blue, Sudan black B and acid haematin. The results suggest that in these cells, considered to be mononuclear phagocytes, there is a storage of hexose-containing mucosubstances, acid mucopolysaccharides and choline-containing phospholipids.