摘要:

SummaryExogenously added N6, O2′‐dibutyryladenosine‐3′‐5′‐cyclic phosphate (DBcAMP) exerted a biphasic effect on thein vitroprimary response of mouse spleen cells to sheep erythrocytes (SRBC). High concentrations of DBcAMP were markedly suppressive, whereas lower concentrations brought about significant increases in the peak numbers of antibody‐forming cells. The kinetics of the response were not altered by DBcAMP. A direct effect of DBcAMP on bone‐marrow derived lymphocytes was suggested because this nucleotide increased thein vitroresponse of “nude” mouse spleen cells to SRBC. The magnitude of the response, however, was considerably less than that mounted by spleen cells of normal mice. These results show that DBcAMP can have either enhancing or suppressive effects on antibody formation and these effects are dependent upon nucleotide concentration, antigen‐dosage and time of assay. The effects of this cyclic nucleotide differed in two major respects from those of the synthetic polyribonucleotide adjuvant, polyadenylic acid‐polyuridylic acid (poly A:U) complexes. Thus poly (A:U) decreased the time of peak responsein vitrobut did not increase the magnitude of the response.

ISSN:0004-945X    

DOI:10.1038/icb.1976.1

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryThe effect of mouse interferon preparations on the primaryin vitroantibody response of mouse spleen cells was studied. Concentrations of interferon greater than 8 units per ml significantly inhibited the antibody response while low concentrations of 0·08–0·8 units per ml could be shown to be mildly enhancing.Various treatments which affected the antiviral activity of the interferon preparations reduced the immunosuppressive activity to a similar extent.Interferon acts during the first few hours of a response but the effect is not apparent for at least 50 h. Interferon had no effect when added after 48 h. The kinetic data has been interpreted as demonstrating interferon‐sensitive and interferon‐resistant components of thein vitroresponse.The results from investigations of the polyclonal response to lipopolysaccharide support the view that interferon acts mainly on B cells alone, although effects on T‐B interactions cannot be excluded.

ISSN:0004-945X    

DOI:10.1038/icb.1976.2

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryColonies of human lymphocytes with T cell characteristics will grow in agar from repeated mitotic divisions with phytohaemagglutinin (PHA) stimulation. The colonies comprise spheres of tightly‐packed cells with up to 500–1,000 blast‐like cells in each colony. 65% of cells from pooled colonies bound AET‐treated sheep red cells. 1,100–2,500 colonies/106peripheral blood lymphocytes developed when cell donors were healthy but lower numbers (350–1,000 colonies/106lymphocytes) were detected in blood from cancer patients. Comparison with other non‐specific assays of cell‐mediated immunity showed that, while 66% of cancer patients were anergic (to five recall antigens) and 78% exhibited depressed mitotic activity in standard cultures with low dose PHA, 100% of these patients revealed T cell colony formation below normal. It is suggested that further studies of T lymphocyte colony‐forming cells in healthy people and in a number of disease states may significantly advance our understanding of mechanisms of cell‐mediated immunity.

ISSN:0004-945X    

DOI:10.1038/icb.1976.3

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryElectrolysis of 3‐niethoxycatecholamines in physiological solutions resulted in the formation of the parent catecholamines and their oxidation products. Conversion occurred at the anode. Maximal catecholamine production occurred in the presence of ascorhic acid.

ISSN:0004-945X    

DOI:10.1038/icb.1976.4

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryCells in the secretion of involuting and non‐lactating mammary glands of the ewe were studied. Light microscopy studies revealed that the majority of the cells were mononucleated, but it was impossible to distinguish macrophages from sloughed epithelial cells. Electron microscopy studies showed that the majority of die cells were macrophages and that they phagocytosed polystyrene latex spheres. Very few epithelial cells were found and they were distinguished from macrophages by numerous microfilaments and blunt microvilli. Epithelial cells could he further distinguished from macrophages by the presence of tight junctions.Tissue culture of cells in secretion of mammary glands revealed the predominant cell type to be the macrophage. After 3 days in culture these macrophages formed multinucleated giant cells which contained acid‐phosphatase granules. Fluorescein‐labelled antiserum prepared against the cell cultures, stained cells in the lumens of alveoli and duets, but not epithelial cells, in frozen sections of mammary tissue.The study confirms previous findings that the large majority of cells from mammary glands in late involution are macrophages. It also points to the usefulness of non‐lactating mammary glands as a source of sheep and cattle macrophages.

ISSN:0004-945X    

DOI:10.1038/icb.1976.5

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryPancreatic islets have been isolated from the exocrine pancreas of inbred rats by the collagenase digestion method. Transplantation of isolated islets into the portal venous system of streptozotocin‐diabetic recipients resulted in complete abrogation of the diabetic state us measured by non‐fasting serum glucose levels, 24 h urinary output, rate of weight gain and glucose tolerance test. Transplantation to other sites resulted in less than optimal survival and function of islets. Allogeneic islets, transplanted across weak histocompatibility barriers, can survive and function for prolonged periods of time when transplant recipients are immunosuppressed with antilymphocyte serum (ALS). Recipients of allogeneic islets, after a period of immunosuppression with ALS, become permanently tolerant to the allografted islets and to subsequent skin grafts from similar allogeneic donors. Allografted islets are able to prevent the occurrence of diabetic renal and ophthalmic changes that occur in control diabetic animals which had not undergone transplantation.

ISSN:0004-945X    

DOI:10.1038/icb.1976.6

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryThe blood concentrations of aldosterone, corticosterone and cortisol were measured in conscious, non‐stressed guinea‐pigs using a double isotope dilution derivative assay procedure. Aldosterone levels in the guinea‐pig were high when compared with those of other species. The concentration of aldosterone, 37·9. ± 15·9 ng/100 ml (χ ± SD), and cortisol, 31·8 ± 10·1 μg/100 ml, found in non‐pregnant females on a moderate sodium intake was significantly greater than in males (aldosterone 22·2 ± 2·4 ng/100 ml and cortisol 19·3 ± 5·7 μg/100 ml). There was no sex difference in corticosterone concentration; females, 0·25 ± 0·06 μg/100 ml and males, 0·23 ± 0·10 μg/100 ml. The oestrus cycle had no effect on levels of the three steroids measured. Two thirds of the way through the 68‐day gestation period aldosterone levels were significantly elevated compared with non‐pregnant values (68·7 ± 50·9 ng/100 ml versus 37·9 ± 15·9 ng/100 ml, p<0·05). Values at day 20 (33·2 ± 11·7 ng/100 ml) and day 60 of gestation (51·9 ± 21·7 ng/100 ml) were similar to those of non‐pregnant animals. Cortisol and corticosterone levels were significantly elevated at 20 days gestation and they continued to rise until, at day 60, cortisol was 9 times and corticosterone 4 times higher than the non‐pregnant values. Compared with a moderate Na intake, salt loading suppressed aldosterone levels and Na restriction raised them.

ISSN:0004-945X    

DOI:10.1038/icb.1976.7

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryThe effect of denervation of the pyloric antrum and of subsequent vagotomy on the secretory responses of an innervated or a denervated gastric‐pouch in the dog to histamine and pentagastrin was determined. The increased sensitivity of the gastric pouch to stimulation after these procedures is in keeping with the concept that an inhibitory reflex is concerned with the control of acid gastric secretion.

ISSN:0004-945X    

DOI:10.1038/icb.1976.8

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummarySalmonellin production on agar was reduced by adding streptomycin or raising the incubation temperature to 44°. Production of group 3b salcol was increased by incubation at 44° and, for one producer only, by adding streptomycin. Production of the diffusible, nontransferable group 4 salcol and also of diffusible colicin V was reduced at 44°. Group 1 salcol production was unaffected by raised temperature or streptomycin. Group 2 salcol production also was unaffected, except in salm+ transcipients of Arizona So116 where it was reduced along with salmonellin production by incubation at 44° or addition of streptomycin.

ISSN:0004-945X    

DOI:10.1038/icb.1976.9

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY

摘要:

SummaryThe effect of a standardised exercise procedure on plasma growth hormone (HGH) and prolactin has been assessed in 10 normal human subjects. Each subject was tested in an ambient temperature of 40° and on a subsequent day at a temperature of 10°. At 40° exercise produced an increase in HGH in all 10 subjects, while in the cold only 1 showed a rise in the hormone during exercise. An increase in prolactin with exercise at 40° occurred in some of the subjects, but these changes were small in comparison with those of HGH. Prolactin levels did not increase during exercise in the cold.

ISSN:0004-945X    

DOI:10.1038/icb.1976.10

出版商:Nature Publishing Group    

年代:1976

数据来源: WILEY