An estimation of the fibre type compostion of eleven skeletal muscles from New Zealand White rabbits between weaning and early maturity

Fibre types in 11 skeletal muscles from New Zealand White rabbits were differentiated on the basis of histochemical staining reactions for Ca2+-adenosine triphosphatase (Ca2+ATPase) at pH 9-4, cytochrome oxidase, succinate dehydrogenase and L-glycerol-3-phosphate:menadione oxidoreductase activities. Using these enzyme reactions it was convenient to divide muscle fibres into three main categories in 'white' muscles and two in 'red' muscles. Between weaning and early maturity most muscles showed little change in fibre type composition, particularly when Ca2+-ATPase activity was used as the criterion. Many muscles showed an uneven distribution of fibre types in transverse sections; this was particularly so in the cases of longissimus, semitendinosus, soleus and semimembranosus proprius. The methods successful in resolving fibre types in mature muscles were not so capable of resolving fibre types in neonatal muscles.

Microflora of pneumonic lungs in a pig herd established by hysterectomy

Mycoplasmas and other micro-organisms are recorded from a pig herd originally derived by hysterectomy. Complement fixation tests were positive for Mycoplasma hyopneumoniae 20 months after the first hysterectomy. Following a marked increase in pneumonic lesions found at slaughter, and after modifying the culture medium M hyopneumoniae was isolated. The principal micro-organism associated with this mycoplasma was Pasteurella multocida.

Receptors for antibody-opsonic adherence on the eosinophils of guinea pigs

Eosinophils have recently been implicated in antibody-dependent cell-mediated damage to schistosomula. Because of this, eosinophils of the guinea pig have been examined for surface receptors capable of giving antibody opsonic adherence; a rosetting reaction has been used. The eosinophils were shown to possess Fc receptors for homologous immunoglobulin. No selective difference between IgG1 and IgG2 was observed. In marked contrast to macrophages, guinea pig eosinophils failed to show opsonic adherence to red cells sensitized to a comparable degree with rabbit antibody. With red cell antibodies made in the pig, however, the reciprocal situation held, namely opsonic adherence was stronger with eosinophils than with macrophages.

Increased sensitivity of the rosette-forming reaction of human T lymphocytes with sheep erythrocytes afforded by papain treatment of the sheep cells

Human T lymphocytes are known to adhere to sheep erythrocytes. This affinity reaction was found to be consistently increased following treatment of the sheep cells with papain. Reactions with treated erythrocytes were more stable and involved higher percentages of lymphocytes. Using a double marker system of papain-treated sheep erythrocytes together with Fc rosettes as a presumptive B-cell marker, there was an overlap population of only 1% lymphocytes. Sheep erythrocytes treated with papain therefore appear to remain specifically adherent to human T lymphocytes.

Increased affinity of guinea pig thymocytes and thymus-dependent lymphocytes for papain-treated rabbit erythrocytes compared to untreated erythrocytes

The affinity of guinea pig thymocytes and peripheral T lymphocytes for rabbit erythrocytes was found to be enhanced following treatment of the erythrocytes with papain. By increasing the numbers of rosette-forming cells and giving stronger, more stable rosettes, this procedure increases the usefulness of the reaction as a T cell marker in guinea pigs.

Observations on rabbit thymocytes and peripheral T cells. II. Rosette formation with rabbit erythrocytes

The affinity of rabbit thymocytes and a proportion of lymphocytes for homologous and autologous erythrocytes has been investigated. Thymocytes were found to rosette strongly with untreated, washed erythrocytes, although reactions on peripheral lymphocytes from blood and lymph nodes were weaker. Enzyme treatment of the erythrocytes was used in attempts to improve reactions with peripheral lymphocytes. While neuraminidase-treated cells showed no increased reactivity, erythrocytes treated with papain were more firmly bound and reacted with greater numbers of blood and lymph node cells. Evidence was obtained to show that peripheral lymphocytes which have an affinity for papain-treated erythrocytes belong to the thymus-derived T cell population.

Populations of guinea pig lymphocytes and Kurloff cells characterised by rosette-forming reactions

The affinity of guinea pig lymphoid cells for rabbit red cells was employed for the detection of T cells, while B cells were identified by antibody opsonic (Fc), complement receptor (EAC) and mixed antiglobulin reactions. Rabbit red cells formed rosettes both with blood lymphocytes (18–42%) and with Kurloff cells (7–34%) indicating a possible thymic influence on the latter. There was no correlation between numbers of T lymphocytes and reacting Kurloff cells. Sub-optimal rosetting reactions were obtained when either the rabbit red cells or the blood lymphocytes were stored at 4 °C for several days. There were no significant differences in percentages of rosette-forming lymphocytes, or Kurloff cells when reacted with red cells from 7 rabbits. The highest results in tests for B lymphocytes in blood were obtained with the mixed antiglobulin reaction (2–27%) but all three reactions were usually negative on Kurloff cells. The possible significance of these findings is discussed. There was little daily variation in levels of T and B lymphocytes in the blood of normal guinea pigs. The percentages of T and B cells were also measured in lymph nodes (8–11% T and 7–23% B) and thymus (60–82% T and 2% B) of normal guinea pigs. It is apparent that in all tissues tested there is a variable number of cells which react neither with rabbit red cells, nor in the mixed antiglobulin reaction. Rosette-forming reactions provide a convenient method of assessing T and B lymphocyte levels in the guinea pig blood. The results have a normal frequency distribution and levels for a group of 46 normal guinea pigs were 26.5 ± 8.3% for T and 6.5 ± 4.3% for B lymphocytes.

Studies on actively allergized cells. IV. Light and electron microscopic studies on the morphology of rosette-forming cells with special reference to plasma cells

A proportion of the plasma cells in lymph nodes of allergized guinea-pigs and mice were found to possess membrane-bound receptors for antigen when tested for rosette-formation at 4° by the suspension-centrifugation technique. This was shown by staining rosetted cells with pyronin-methyl green. Rosette-forming cells of the guinea-pig were further examined by staining with fluorescein-conjugated antigen (rabbit Fab′) and by electron microscopy. By these techniques it was found that many plasma cells which contain antigen-specific intracellular antibodies do not form rosettes, and that cells of the plasmacytic series represented in the rosetted population are limited to plasmablasts and immature plasma cells. The lack of rosette-forming mature plasma cells suggests that a loss of receptors from the cell-membrane occurs as an accompaniment to maturation.

Rosette-formation between guinea pig lymphoid cells and rabbit erythrocytes--a possible T-cell marker

A proportion of guinea pig lymphoid cells have an affinity for rabbit erythrocytes which is demonstrable by a rosette-forming technique. In normal adult guinea pigs, this reaction has been shown to occur with up to 89% thymus cells, 26% lymph node cells and 55% peripheral blood lymphocytes. This rosette-formation which occurred on both live and dead lymphoid cells was not inhibited by anti-immunoglobulin serum. Very few, if any, of the peripheral lymphocytes which form rosettes with rabbit erythrocytes also have detectable Ig-determinanls on the cell membrane. It is suggested that this affinity for rabbit erythrocytes may form a marker for thymus-derived (T) lymphocytes in guinea pigs in the same way as rosette-formation with sheep erythrocytes appears to afford a T-marker for human lymphocytes.

Quantitative analysis on isolated organs of the autonomic blocking properties of indoramin hydrochloride (Wy 21901)

1. Indoramin is a competitive alpha-adrenoceptor blocking agent on the guinea-pig isolated vas deferens and aortic strip; the pA(2) value on the aorta is 7.4.2. Indoramin is devoid of beta-adrenoceptor blocking activity on the guinea-pig isolated trachea (10(-4)M) and the Langendorff preparation of the rabbit heart (10(-6)M). It also has no adrenergic neurone blocking action on the Finkleman preparation of the rabbit small intestine (10(-5)M).3. On the Langendorff preparation of the rabbit isolated heart, indoramin (above 10(-6)M) has cardio-inhibitory properties similar to those of propranolol.4. On the guinea-pig isolated ileum (10(-5)M) and trachea (10(-6)M), indoramin is devoid of anticholinergic activity, but has a potent antihistamine action which satisfies the criteria for competitive antagonism; the pA(2) value for this antagonism on the ileum is 8.2.5. Indoramin antagonizes 5-hydroxytryptamine on the rat isolated fundus and ileum; the pA(2) value for the antagonism on the ileum is 6.0.

Reaginic antibodies on basophils in grass pollen allergy, as shown by rosette-formation

Antibodies to grass pollen allergens have been demonstrated on basophils of individuals with hay fever by means of a rosette-forming reaction with allergen-coated erythrocytes. The antibodies on the basophil cell membrane were shown to be IgE by inhibition of rosette-formation with specific anti-<i>&#917;</i> serum. Not all persons giving positive skin reactions to grass pollen extracts had basophils capable of rosette-formation.