摘要:

SummaryThe uptake of transferrin and iron by rat liver tissue was measured usingin vivoscreened radioiodinated rat albumin and transferring,59Fe and three experimental techniques using liver slices, the isolated perfused liver or the intact animal. Uptake of labelled transferrin in excess of that of albumin relative to their concentrations in the solutions bathing the liver cells was found with all three techniques. This was considered to represent specific uptake of transferrin by liver cells. It occurred rapidly to reach an equilibrium within 30 min in the perfused liver and the intact animal but was slow with liver slices. More than half of the transferrin specifically bound by the liverin vivowas released into the perfusate during subsequent perfusion.Radioiron uptake in excess of radioiodinated transferrin uptake was also found with all three techniques and was used to measure the rate of cellular uptake of iron. This was tow with liver slices but the values for the perfused liver were comparable to the rate foundin vivo.It is concluded that transferrin is reversibly taken up by rat liver cells, probably during the process of assimilation of plasma iron, and that the isolated perfused liver is superior to liver slices as a technique to study the mechanism of iron uptake by the liver.

ISSN:0004-945X    

DOI:10.1038/icb.1974.72

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryThein vitrointeraction between human leucocytes and tumour cells from eight patients with malignant melanoma and three with colonic carcinoma was studied in parallel samples using the phase‐contrast and electron microscopes. Interaction of a conceivably specific type, “peripolesis” and “emperipolesis”, was seen between autologous lymphocytes and tumour cells in six of the melanoma cases and two of the colonic carcinoma cases. It is concluded that a direct autologous lymphocyte‐tumour cell interaction is the morphological expression of part of thein vitrocytotoxicity mechanism by which cytotoxic lymphocytes induce target cell destruction. No evidence of specific involvement of any other type of leucocyte was found.

ISSN:0004-945X    

DOI:10.1038/icb.1974.73

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryUsing a microleucocyte migration inhibition technique, comparable to the macromethods currently in use, it was shown that peripheral leucocytes from normal human subjects underwent migration inhibition in response to antigens prepared from their own gut flora. This system was used to study the kinetics of leucocyte migration. It was shown that antigen‐induced inhibition of migration is mediated by an event which occurs within three hours of culture initiation.

ISSN:0004-945X    

DOI:10.1038/icb.1974.74

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryThe biological properties of the homocytotropic antibody (HCA) of the marsupialSetonix brachyurus(the quokka) were closely comparable to those of eutherian (placental species) IgE. However, the quokka HCA was indistinguishable from the IgG1class. Agar gel electrophoresis, Sephadex G‐200 chromatography and sequential elution from DEAE‐cellulose and CM‐cellulose did not separate the passive cutaneous anaphylactic (PCA) and IgG1passive haemagglutination (HA) activities in quokka antisera. No antigenic differences between the IgG1HA antibody and the HCA were detected. In addition to quokka IgG1, tissue‐fixing IgG has been demonstrated in eutherian and avian species and thus it is suggested that the extant IgG and IgE classes evolved from a primitive cytotropic γ chain.

ISSN:0004-945X    

DOI:10.1038/icb.1974.75

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryMultiple samples of normal human bone marrow from different donors have been fractionated on discontinuous albumin gradients and the nutrient agar system utilised as an assay procedure for the detection of colony‐forming cells in the resulting fractions. The colony‐forming cell, an early granulocytic progenitor, is consistently present in the lighter density fractions. There appeared to be no clear separation of this cell from the T lymphocyte population. The colony‐forming cell whose proliferative status was unaltered during the fractionation process could be clearly separated from the differentiated granulocytes on these gradients. In a potential marrow transplant situation it appears that greater resolution will be necessary than is afforded by albumin gradients for the separation of haemopoietic stem cells from cells responsible for graft versus host disease.

ISSN:0004-945X    

DOI:10.1038/icb.1974.76

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryMice were immunized with livingSalmonella enteritidisand then challenged at various tunes up to 20 weeks withSalmonella typhimuriumC5. The resistance or the immunized mice at the time of challenge was determined by survival of these mice for a period of 28 days or by comparison of liver, spleen and blood counts of the challenge population obtained from normal and immunized mice. Results of survival experiments indicated that the immunization produced effective and long lasting immunity, although bacterial enumeration studies showed that the level of resistance induced was not sufficient to achieve complete, rapid elimination of the challenge organism from the tissues.Mice immunized with S.enteritidis11RX showed both Arthus reactivity and delayed type hypersensitivity to S.typhimuriumC5 antigens, and the serum from these mice was shown to contain antibody activity, as determined by haemagglutination of sheep erythrocytes coated with S.typhimuriumC5 lipopolysaccharide andin vitrobactericidal action against S.typhimuriumM206.

ISSN:0004-945X    

DOI:10.1038/icb.1974.77

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryThiry and double re‐entrant jejunal loops were prepared in adult sheep and young lambs to study antibody responses following local and systemic administration of soluble and particulate antigens. Systemic administration of both livingBrucella abortusand ferritin elicited an IgG response in serum and intestinal secretion. Repeated local infusions of living and killedBr. abortusinto isolated intestinal loops failed to elicit a significant response. However, local infusions of egg albumin or ferritin resulted in the appearance in intestinal secretion of substantial amounts of antibody most of which was associated with IgA. The results obtained using lambs demonstrated that local antibody production associated with IgA occurred after antigenic stimulation of intestinal loops in animals as young as 3 weeks of age.

ISSN:0004-945X    

DOI:10.1038/icb.1974.78

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryThe pulmonary vascular response to hypoxia was studied in open and closed chest anaesthetised sheep. Control distributions of pulmonary blood flow were significantly different between the open and closed chest animal, and changes in total pulmonary vascular resistance during hypoxia were identical in the two preparations. There were, however, marked regional differences in the response of the pulmonary vasculature to hypoxia in both preparations, there being greater increases in vascular resistance in the central zone of the lungs between the dorsal and ventral surfaces of the supine animal.

ISSN:0004-945X    

DOI:10.1038/icb.1974.79

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryMethysergide, dihydroergotamine, ergotamine and 1‐methylergotamine potentiated the response of both the human temporal and rabbit ear artery to noradrenaline. In higher doses, these drugs caused constriction of the rabbit arteries, but had little constrictor effect on the human vessels. Cyproheptadine and pizotifen did not cause either potentiation or direct vasoconstriction on either artery type. Pizotifen abolished the direct constrictor action of 5‐hydroxytryptamine (5HT) while leaving its potentiating properties unaffected; it also abolished the constrictor effects of methysergide but was without effect on the constrictor actions of the ergot derivatives. It is concluded that of the drugs tested only methysergide constricts the arteries by a direct action on 5HT receptors, and that 5HT, methysergide and the ergot derivatives have comparable activities at a separate receptor which is responsible for potentiation. It is suggested that, in the treatment of migraine, the therapeutic value of methysergide and the ergot derivatives, hut not cyproheptadine or pizotifen, may lie in their ability to replace 5HT as a sensitizing agent.

ISSN:0004-945X    

DOI:10.1038/icb.1974.80

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY

摘要:

SummaryBurimamide, an H‐2 receptor antagonist, was administered to intact and anaesthetized dogs. The drug increased heart‐rate, cardiac output and systemic pressure during its infusion and for 30 minutes afterwards. Coronary sinus flow was not significantly changed. There was an increase in right and left ventricular work with a decrease in the calculated resistances in the pulmonary and systemic circuits. Lactate, pyruvate, and non‐esterified fatty acid levels increased. Burimamide is able to reverse the depressant effects of histamine release by Tween 20, but pretreatment with burimamide does not have any prophylactic effect upon the histamine response.

ISSN:0004-945X    

DOI:10.1038/icb.1974.81

出版商:Nature Publishing Group    

年代:1974

数据来源: WILEY