Cholecystokinin antagonist and lipid intake as a function of caloric density and familiarity.

The effect of treatment with the cholecystokinin antagonist L364,718 on intake of different dilutions of corn oil emulsion was tested under two levels of familiarity with the oil emulsion. No increase in intake was observed. To see if the CCK antagonist was effective under our conditions, exogenous CCK was administered under the same conditions. A complete suppression of the large reduction produced by CCK on intake was found.     

慢性低氧时小鼠肺组织低氧诱导因子-1α的表达

目的：研究低氧时小鼠肺组织中低氧诱导因子-1α(HIF-k)表达的变化。方法：实验用雄性小鼠，低氧仓浓度分别为10％、7％、5％。用免疫荧光组织化学技术及共聚焦显微术，检测小鼠在低氧条件下肺组织中HIF-1α表达的变化。结果：正常组小鼠肺组织HIF-1α无表达，低氧组HIF-1α表达增加，且随低氧时间的延长及低氧强度的增加而增强。结论：低氧可诱导小鼠肺组织中HIF-1α的表达增强，(HIF-k)可能参与肺组织细胞凋亡的发生。     

The influence of different cultivating conditions on polymorphonuclear leukocyte apoptotic processes in vitro,I: the morphological characteristics of PMN spontaneous apoptosis

Polymorphonuclear leukocyte (PMN) populations incubated in vitro with normal human serum are save-regulated systems of spontaneous apoptosis. Light microscopy (LM), transmission (TEM), and scanning (SEM) electron microscopes were used for the evalution of PMN apoptopic alteration. Twelve-hour PMN populations were represented by optimal number of normal and different apoptotic forms. Their ultrastructural analysis showed that on this background, 3 apoptotic cell lines (code named "first," "second," and "third") were predominated. The following characteristics were featured: "first"--vacuolization of same organelles, release of their content outside, increase of general cytoplasmic density, nuclear filling with condensed chromatin, and formation of PMNs mainly into small, round, dense forms; "second"--involvement of micronuclei or nuclei in apoptosis, their displacement to the cytoplasmic membrane and separation from the cells, and cytoplasm had numerous intact granules almost until the completion of apoptosis; "third"--synchronous apoptotic process of the nuclei and cytoplasm, moderate electronic density of cytoplasm, and granular translocation to the cell surface. Secondary necrosis was completed mainly in the apoptotic process of the "second" and "third" lines. SEM surfaces confirmed the results of TEM. This research showed that neutrophil spontaneous apoptosis is a complicated process. The 3 apoptotic cell lines reflect different pathways characteristic for the studied systems under certain conditions of cultivation.     

In vitro stimulation of antibody formation by peritoneal cells: III. Effect of active immunization on the subsequent in vitro performance of peritoneal and spleen cells

Male CBA mice were given a single intraperitoneal injection of sheep red blood cells (SRBC) or horse red blood cells (HRBC). They were killed at intervals of 1–10 days thereafter, and micro-cultures of spleen cells or peritoneal cells (PC) were prepared. These consisted of a thin film of tissue culture medium containing carboxymethyl cellulose (CMC), mouse lymphoid cells, guinea-pig complement and either SRBC or HRBC, held at 37° under liquid paraffin. Cultures were read repeatedly for appearance of haemolytic plaques.

PC from SRBC-immunized mice showed an altered reactivity on SRBC monolayer cultures. The peak plaque count achieved in vitro fell progressively for 4 days after immunization, and then returned to normal by day 7. The actinomycin D resistant component of the PC response rose rapidly; at 1 day after immunization it was equal to the total response. Over the next 3 days after immunization it fell again to normal levels. The results suggested that the in vivo injection sets in train events locally in the peritoneal cavity which resembled those following in vitro culture of normal PC in SRBC monolayers. The effects were immunologically specific as only marginal changes followed the injection of HRBC.

Spleen cells from SRBC-immunized mice, when cultured in SRBC monolayers, yielded many cells capable of giving plaques after 5–60 minutes incubation, as expected. These were deemed to be cells forming antibody at the moment of killing of the animal. In addition, such cultures developed new plaques over the subsequent 23 hours in culture. These were produced by cells not initially forming antibody which switched into antibody secretion at some time during culture. At early time points after immunization, this second type of cell was much more numerous than the first type. The switch from non-secretor status could occur in the presence of a high concentration of actinomycin D. Operationally these non-secretors in immunized spleens resembled an important fraction of PC from unimmunized retired breeder mice. The progressive conversion of non-secretor cells into secretors, if it occurs in vivo, would have a major influence on the kinetics of appearance of PFC in a spleen after immunization.

While spleen cells from mice immunized with HRBC performed on HRBC monolayers much as described above, PC from HRBC-immunized mice could not be induced to cause significant lysis in HRBC monolayers. The same was true of PC from mice chronically fed with HRBC. In fact, no method has yet been found to persuade PC to produce lytic plaques active against erythrocytes other than SRBC.

     

Immune responses to weakly immunogenic virally induced tumors II. Suppressive effects of the in vivo carried tumor YAC

Unprimed spleen cells from A and C57BL/6 mice could not produce cytotoxic responses to their syngeneic tumors: a Moloney virus-induced in vitro subline YAC-1 and a Rauscher virus-induced in vitro subline RBL5, respectively. Spleen cells from A and C57BL/6 mice immunized with YAC-1 or RBL5 (which cross-react serologically) generated significant syngeneic cytotoxicities after cultivation in vitro. The in vivo carried tumor of A mice, unlike the in vitro sublines, could not stimulate a priming effect. In contrast, YAC stimulated the formation of suppressor cells in both A and C57BL/6 mice. The suppressor cells abrogated the priming effect of the syngeneic tumors, but not the priming effect of the allogeneic tumors. Furthermore, YAC did not suppress normal allogeneic anti-tumor responses. The theoretical and the practical implications of these studies are discussed.     

Induction of biologically active antineutrophil cytoplasmic antibodies by immunization with human apoptotic polymorphonuclear leukocytes

Translocation of intracellular components to the cell surface during the priming or apoptosis of polymorphonuclear leukocytes (PMN) is an important mechanism for interaction of antineutrophil cytoplasmic antibodies (ANCA) with these antigens. To test the capacity of apoptotic PMN to trigger production of ANCA, six groups of mice were immunized with either live or apoptotic lymphocytes, or with live, apoptotic, formalin-fixed, or lysed PMN. Mice immunized with both live and apoptotic neutrophils developed high titers of antibodies which gave a granular cytoplasmic immunofluorescent pattern. These antibodies were specific for lactoferrin and myeloperoxidase. Following a second intravenous infusion of apoptotic PMNs, mice developed anti-PR3 antibodies. Vasculitis lesions were not found in mice which developed ANCA. The ANCA-containing IgG fraction induced superoxide production by human PMNs. These results support the hypothesis that neutrophil-specific antigens presented on the cell membranes of apoptotic PMN may induce ANCA in the proper conditions.     

<Emphasis Type="Italic">TCF7L2</Emphasis>variant genotypes and type 2 diabetes risk in Brazil: significant association,but not a significant tool for risk stratification in the general population

Background  

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.     

Immunofluorescent studies of the endometrial arteries in the first trimester of pregnancy

Endometrial spiral arteries from curetted endometrium of 110 first-trimester pregnancies were studied by immunofluorescent (IF) technics using antibodies against human G, M, and A immunoglobulins, C3, C4, and fibrinogen. Heavy deposition of C3 in the arterial walls was found in 16 (14.6%) cases. Immunoglobulins, C4, and fibrinogen were found in only a few cases, and their staining was weak and not considered in this study. There was also a statistically significant (P less than 0.01) higher deposition of C3 in arterial walls of primipara (14 of 52), as compared to multipara (2 of 58). The possible mechanisms of C3 deposition and the importance of the higher incidence of this deposition in primipara are discussed in relation to suggested immunologic pathogenetic alterations in preeclampsia.     

Stimulation of β-adrenoceptors inhibits store-operated channel currents via a cAMP-dependent protein kinase mechanism in rabbit portal vein myocytes

Previously we have described the properties of store-operated channel currents (SOCs) in freshly dispersed rabbit portal vein smooth muscle cells. In addition to Ca²⁺ store depletion these SOCs could also be activated by α-adrenoceptor stimulation and diacylglycerol (DAG) via a protein kinase C (PKC)-dependent mechanism. In the present study we have investigated the effect of β-adrenoceptor stimulation on SOCs in rabbit portal vein myocytes. With whole-cell recording the selective β-adrenoceptor agonist isoprenaline reduced the current evoked by cyclopiazonic acid (CPA, sarcoplasmic/endoplasmic reticulum ATPase inhibitor) by over 85%. With cell-attached patch recording, bath application of isoprenaline produced a pronounced inhibition of SOC activity evoked by either CPA or the acetoxymethyl ester form of BAPTA (BAPTA-AM). SOC activity evoked by CPA, the DAG analogue, 1-oleoyl-acetyl- sn -glycerol (OAG) or the phorbol ester, phorbol-12,13-dibutyrate (PDBu) was also markedly inhibited by the adenylate cyclase activator, forskolin, and the cell-permeable non-hydrolysable analogue of cyclic adenosine monophosphate (cAMP), 8-Br-cAMP. With inside-out patches, bath application of PDBu evoked channel currents with similar properties to SOCs which were inhibited by over 90% by a catalytic subunit of protein kinase A (PKA) and by 8-Br-cAMP. Moreover bath application of PKA inhibitors, H-89, KT5720 and an inhibitory peptide to quiescent cell-attached or inside-out patches, activated channel currents with similar properties to SOCs. These data suggest that in rabbit portal vein myocytes, stimulation of β-adrenoceptors inhibits SOC activity via a cAMP-dependent protein kinase signal transduction cascade. In addition it is concluded that constitutive PKA activity has a profound inhibitory effect on SOC activity in this vascular preparation.