摘要:

SummaryThe incidence of lymphoma was lowered from 62 per cent to 27 per cent by post‐irradiation bone marrow grafting, and there was an inverse relationship between the “take” of chromosomally labelled donor cells of bone marrow and lymph node origin and the incidence of lymphoma. The postulate that inhibition of lymphoma is due to colonization of the host's tissues by unirradiated graft cells (with suppression of activity of the host's own radiation damaged cells) appears only partly true, for even the cells of donor origin which had successfully colonized the irradiated hosts' tissues were subject themselves to malignant transformation.The inability of lymphocytes to protect against the supervention of lymphoma is reflected in their inability, observed cytogenetically, to penetrate the thymus. When equal numbers of haemopoietic cells and lymphoid cells have been given intravenously to lethally irradiated mice the same thymic barrier effect has been seen. Combining the cytogenetic data and the information from mitotic rates in bone marrow and thymus, it was apparent that it was a cell derived from the recolonized haemopoietic stores which gained entry to the thymus.No contrast was shown between chimacras resuscitated with foetal haemopoietic cells, and supplemented with adult or newborn lymphocytes, or thymocytes in the restoration of the blood count and the lymphocyte/neutrophil ratio. It must be assumed, in the absence of cytogenetic evidence to the contrary, that consequent upon failure of lymphoid material to colonize the thymus the circulating lymphocytes were derived from the grafted haemopoietic elements. It appeared that they were immunologically competent.

ISSN:0004-945X    

DOI:10.1038/icb.1965.44

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryWhen healthy dairy calves were subjected to a single blood withdrawal of 10, 20 or 30 ml./kg. body weight, levels of plasma total iron‐binding capacity increased. Plasma iron concentrations also increased significantly after bleeding at the two highest levels, but were unaffected by a blood loss of 10 ml./kg. The bleeding of calves daily for two weeks at rates of 2, 4 or 6 ml./kg./day similarly caused significant increases in plasma total iron‐binding capacity. Blood losses of 2 or 4 ml./kg./day resulted in an elevation of plasma iron concentration. However, phlebotomies of 6 ml./kg./day eventually caused a marked depression of plasma iron levels, but, when the bleedings were terminated, plasma iron concentrations increased to abnormally high values. It is suggested that the increased plasma iron levels were due to an increased absorption of dietary iron. Labile iron reserves in the experimental calves were estimated to lie within the range of 1·0‐1·4 g., and were associated with liver concentrations of non‐haem iron of about 30 μg./g. of wet liver. In calves, levels of non‐haem iron in liver tissue of less than 20 μg./g. appear to be indicative of iron deficiency.

ISSN:0004-945X    

DOI:10.1038/icb.1965.45

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryIt has been found that mice pretreated with thorotrast and then given antigen respond with a prolonged macroglobulin response. Further, if thorotrast is given following antigen stimulation, similar results may be obtained. Various parameters of the system have been investigated and are given below.

ISSN:0004-945X    

DOI:10.1038/icb.1965.46

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryIntravenously injected carbon particles localize selectively adjacent to blood vessels in the metaphysis of long bones of young rats. Deposition is greatest in rapidly growing animals, and decreases as the growth rate slows in older animals.Similar deposition cannot be detected in relation to growing vessels in either granulation tissue or recent tumour implants.Electron microscopic examination shows that the growing ends of metaphyseal blood vessels consist only of attenuated endothelium containing numerous wide gaps. At deeper levels in the metaphysis the vascular wall is much thicker, and resembles actively growing vessels seen in other tissues. Occasional gaps in the endothelium occur here, and neither a basement membrane nor peri‐endothelial cell layer is present.It appears that carbon deposition in the metaphysis is due to the peculiar structure of its small blood vessels, and does not indicate a temporary change associated with an increase in vascular permeability to protein as it does in most other tissues.

ISSN:0004-945X    

DOI:10.1038/icb.1965.47

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryObservations have been made on the effects of nerve stimulation and drugs on an isolated perfused segment of the central artery of the rabbit ear.Stimulation applied transmurally, peri‐arterially or to the ventral auricular nerve caused vascoconstriction.The vascoconstrictor response to peri‐arterial stimulation was due to excitation of nerve fibres arising from the superior cervical ganglion. The response was enhanced after cocaine, and abolished or greatly reduced after guanethidine, procaine and dibenyline.Noradrenaline produced vascoconstrictor responses which were enhanced after ganglionectomy and after cocaine, and abolished by dibenyline.Acetyl choline caused dilatation, but only when the tone of the artery was raised by sympathetic stimulation. The effect of acetyl choline was greatly reduced after atropine.Histamine caused vasoconstriction which was abolished after mepyramine.5‐hydroxytryptamine had only weak vasoconstrictor activity, but it markedly potentiated the action of noradrenaline and sympathetic nerve stimulation.Angiotensin has weak vasoconstrictor activity.

ISSN:0004-945X    

DOI:10.1038/icb.1965.48

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryVascular pressures, cardiac output (Fick) and coronary flow (N2O Fick) were measured before and after the production of hyperkalaemia in intact dogs. Respiratory exchange and heart rate increased; vascular pressures and cardiac output did not vary. There was no significant change in coronary flow, but cardiac oxygen extraction and metabolism increased.

ISSN:0004-945X    

DOI:10.1038/icb.1965.49

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryDesiccates ofSalmonella ndoloin sodium glutamate were exposed to 100° for various periods before sealing. Recoveries of viable organisms from such desiccates after further exposure to 100° and after storage at 45° were much higher than from unheated controls.Slow rehydration of the heated desiccates with nutrient broth yielded higher recoveries than did rapid rehydration.

ISSN:0004-945X    

DOI:10.1038/icb.1965.50

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryThe measurement of radioactivity of skin pieces excised from guinea‐pigs with circulating131I‐albumin provided a useful means of relating increased exudation of the protein to the dose of permeability‐increasing drugs, injected intradermally. Intravenous injection of Evans blue dye, given at the same time as131I‐albumin, permitted visual identification of skin areas with increased vascular permeability, due to the exudation of dye‐albumin complex. After establishing a suitable experimental procedure, linear log dose‐response curves were obtained for three drugs, viz. histamine, bradykinin and compound 48/80.The use of two‐way restraints of Latin and Youden squares for injection patterns meant that the effect of sites of injections, as well as differences between animals, could be determined. Their effects were frequently found to be significant. A 6 × 5 Youden square, divided between two guinea‐pigs, provided a convenient plan for a comparative dilution assay. The linear regressions for histamine and for the polypeptide, bradykinin, were significantly different. The linear regressions for histamine and for the histamine‐liberator, compound 48/80, were significantly parallel. At an equipment level, the dose of compound 48/80 was approximately 27‐fold greater than that for histamine; or 5·6‐fold greater in the comparison of their molar concentrations.

ISSN:0004-945X    

DOI:10.1038/icb.1965.51

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

摘要:

SummaryDesiccates ofStrigomonas oncopelti, four species of leptospirae and the Reiter trcponeme have yielded viable organisms after storage for five years at 4°. At room temperature only the treponeme was successfully preserved.

ISSN:0004-945X    

DOI:10.1038/icb.1965.52

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY

ISSN:0004-945X    

DOI:10.1038/icb.1965.53

出版商:Nature Publishing Group    

年代:1965

数据来源: WILEY