摘要:

SummaryBasophil and eosinophil leucocytes infiltrate the small intestinal lamina propria of guinea‐pigs infected with the nematodeTrichostrongylus colubriformis. By comparing the morphology of both cell types at the site of infection with bone marrow and buffy coat cells, it was found that, after entering the lamina propria, basophils developed an electron lucent halo beneath the granule‐limiting membrane while the characteristic orderly periodicity of the granules changed to a fibrillar or amorphous appearance. The granules also tended to coalesce but remained within the cell. Approximately half the eosinophils at the site of infection developed deficiencies in the amorphous outer matrix of their granules but showed no obvious change in the central electron‐dense cores.

ISSN:0004-945X    

DOI:10.1038/icb.1975.49

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe effect of angiotensin I on renal perfusion pressure, and on basal and isoprenaline stimulated renin secretion, was examined in the isolated perfused rat kidney. The increase in perfusion pressure associated with intrarenal infusion of angiotensin I suggested conversion of the peptide to angiotensin II within the kidney. Basal renin secretion and the stimulatory response to isoprenaline were significantly suppressed by angiotensin I. The converting enzyme inhibitor SQ 20,881, infused at 1,600 × dose of angiotensin I, partially reversed the vasoconstrictor effect of angiotensin I without altering the degree of suppression of renin secretion.

ISSN:0004-945X    

DOI:10.1038/icb.1975.50

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryDuring thein vivoabsorption of Ca by chicks, cholecaleiferol (vitamin D3) increased the translocation of Ca by the mucosal cells of the small intestine and this was accompanied by a greater “turnover” of Ca within these cells. The location of Ca within mucosal cells was studied by differential centrifugation after conventional homogenation of the cells in isotonic sucrose medium at 0°. Most of the Ca was in mitochondria with less than 2% of Ca being in the soluble phase. However, this finding may be misleading since there may be a redistribution of Ca at 0°, with the mitochondria taking up Ca whichin vivowould be located in other parts of the cell. When cells were homogenized in the presence of inhibitors of Ca uptake by mitochondria or were homogenized at 22°–28°. 15–30% of the Ca was found in the soluble cytosol fraction.The uptake of Ca by mitochondria was compared in sucrose media and in this media containing dialysed cell cytosol. The non‐dialysable substances in the cytosol influenced uptake and release of Ca by mitochondria so that more Ca would be in the soluble phase in the presence of cell cytosol. Dialysed cell cytosol from cholecaleiferol‐pretreated chicks had greater effects than cytosol from rachitic chicks and this may partially account for the increased translocation brought about by cholecalciferol.

ISSN:0004-945X    

DOI:10.1038/icb.1975.51

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryA role has been sought for the calcium binding protein (CaBP) which is synthesisedde novoafter giving cholecalciferol (CC, vitamin D3) to rachitic chicks. After homogenation of mucosal cells in sucrose media, the CaBP was found in the 78,000 ×gsupernatant. Therefore, the CaBP is either present in the cytoplasm or in some labile membrane structure, e.g. the microvilli, that is disrupted by homogenation. This intracellular CaBP may facilitate diffusion of Ca into intestinal cells. No secretion of CaBP into the lumen could be detected nor did excess CaBP placed in the lumen increase Ca absorption of rachitic chicks.The mitochondria of duodenal mucosal cells contained most of the Ca being translocated by the small intestine. CaBP caused release of Ca already present in mitochondria and diminished Ca uptake by mitochondria and it appeared to do this by increasing the rate of Ca flux across the mitochondrial membrane. This would explain the greater “turnover” of Ca in mucosal cells of cholecalciferol‐treated chicks. These and previous findings have been used to propose a scheme for the effect of cholecalciferol on Ca transport from the small intestine.

ISSN:0004-945X    

DOI:10.1038/icb.1975.52

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryIntravenously injected14C labelled oxalate was rapidly removed from the blood stream via the kidney in 2 sheep, 75% being cleared within 8 h. Mean daily urinary oxalate excretions over 5 days were 21·2 and 27·5 mg and the derived plasma oxalate concentrations were 52·6 and 74·4 μg/100 ml, respectively. Oxalate was both filtered and secreted by the renal tubule with oxalate/inulin ratios varying from 1·11 to 1·57 in 6 normal sheep. A large increase in calcium excretion induced by calcium borogluconate infusion over 5 days was accompanied by a small but consistent increase in urinary oxalate excretion relative to calcium.Oxalate in blood was to be found mainly in the plasma, there being a small (8%) proportion within erythrocytes. This is lower than that reported for man, and yet in its excretion of oxalate via the kidney the sheep appears to closely resemble man and dog.

ISSN:0004-945X    

DOI:10.1038/icb.1975.53

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummarySheep erythrocytes of high and low potassium types were incubated in non‐haemolytic hypotonic and hypertonic media for 4·5 h at 30°, After initial swelling or shrinking, they readjusted their volume toward their initial isotonic volume. The volume regulation was associated with specific changes in cation fluxes. In the swollen cells, efflux of both sodium and potassium was increased and influx of both cations was slightly decreased; the converse was true for the shrunken cells. All four fluxes were changed in a direction that led to return to normal volume. The difference in the response of the two types of sheep erythrocytes to changes of extracellular fluid osmolality resided in the different activity of their cation transport systems. It is concluded that sheep erythrocytes possess some means of regulating their volumein vitrowhich is linked to cation permeability. The exact nature of the physical mechanisms by which they accomplish this remains to be elucidated.

ISSN:0004-945X    

DOI:10.1038/icb.1975.54

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe effect of selective denervation of the pyloric antrum on secretory response to three types of food was determined in 3 dogs with innervated and 4 with denervated stomach pouches. With the antrumin situthis procedure has surprisingly little effect on the total meal responses in innervated pouches, on the variation in response induced by altered buffering capacity of the meals, or on the effect of subsequent vagotomy. However, the antrum appears less sensitive to local stimuli after denervation, as evidenced by the reduced meal response from the denervated indicator pouch after denervation of the antrum.

ISSN:0004-945X    

DOI:10.1038/icb.1975.55

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryCytotoxic effects of lymph and blood components, removed from sheep following renal allografting, were determined byin vitroassay using51Cr labelled donor sheep lymphocytes as target cells. Lytic antibodies were detected in lymph efferent from the node draining the graft site and at lower concentrations in blood serum and in lymph leaving the graft, The cytotoxic antibodies had both complement‐dependent and leucocyte‐dependent functions; thy complement‐dependent antibodies were fractionated and shown to be of IgM and IgG1 subclasses. Cytotoxic cells were found in lymph leaving the graft but not in blood or in lymph efferent from the draining node; those detected in the renal lymph were non‐specific in action and their appearance correlated with increased numbers of macrophages.

ISSN:0004-945X    

DOI:10.1038/icb.1975.56

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryPreparations of ovine polymorphs were stained with fluorosceinconjugated, monospecific anti‐immunoglobulin sera. Approximately 26% of polymorphs specifically stained with anti‐γ2, 16% with anti‐light chain, 24% with anti‐Fab and 24% with anti‐ovine serum. There was no significant staining of polymorphs with anti‐γ1, anti‐μor anti‐α. Cytophilic IgG2could be removed from the cells by incubation at 37° and subsequently replaced by incubation in autologous serum at 4°.

ISSN:0004-945X    

DOI:10.1038/icb.1975.57

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY