CUTANEOUS VASOCONSTRICTION WITH ALERTING STIMULI IN RABBITS REFLECTS A PATTERNED REDISTRIBUTION OF CARDIAC OUTPUT

1. In conscious rabbits, when alerting stimuli elicit vasoconstriction in the ear vascular bed, there is little or no associated change in cardiac output (CO), as measured by chronically implanted Doppler ultrasonic probes. 2. Local anaesthetic injected around the base of the ear substantially diminished the degree of the vasoconstriction elicited during responses. 3. Our results emphasize that selective cutaneous vasoconstriction, an integral part of the response to alerting stimuli in conscious animals, is part of a patterned redistribution of the CO, organized by the brain.     

Total stenosis triggers compensatory responsiveness of carotid and basilar arteries to endothelin-1 and phenylephrine.

The aim of this study was to investigate whether total stenosis of the common carotid artery (ipsilateral) would affect the vascular responsiveness of the contralateral carotid as well as the basilar artery from guinea pigs. With this purpose, the carotid artery was occluded with a silk thread at a position close to its origin. Vascular reactivity experiments using standard muscle bath were performed 7, 15, 30, and 90 days after carotid occlusion. Stenosis induced a progressive reduction in the contraction induced by endothelin-1, phenylephrine and KCl in the ipsilateral carotid, when compared to their respective age-matched SHAM groups. Endothelial removal or incubation of endothelium-intact ipsilateral carotids with L-NAME, a nitric oxide synthase inhibitor, did not alter the response to endothelin-1 or phenylephrine, when compared to the endothelium-intact ipsilateral carotid in the absence of the inhibitor. Interestingly, an increased contractile response to endothelin-1, phenylephrine and KCl was observed in the contralateral carotid. Indomethacin, a non-selective cyclooxygenase inhibitor, prevented the increased contraction to endothelin-1 in the contralateral carotid. Stenosis also induced an increase in the contractile response to endothelin-1 in the basilar artery while the contractile response to phenylephrine and KCl were reduced. Indomethacin, but not L-NAME, prevented the increased contraction to endothelin-1 in the basilar artery. Morphometric analysis showed no differences in the medial area (wall thickness) of carotid or basilar arteries from the stenosis group when compared to their respective age-matched SHAM groups. The present study confirms the importance of adaptation to stenosis on the vascular reactivity of the stenosed artery to different vasoconstrictor agents. Moreover, our results show that stenosis induces alterations of the vascular reactivity on arteries distant from the site of injury. The increased response to endothelin-1 in the contralateral carotid artery and basilar artery seems to involve the release of vasoconstrictor prostanoids from endothelial origin.     

成熟心肌细胞的分离与培养方法

0　引言　我们介绍一种在无血清培养基中分离和培养成熟心肌细胞的方法[1,2],着重强调对优化心肌细胞培养至关重要的分离过程.1　材料　分离装置可用典型的Langandorff装置,配合无菌操作要求,对心脏进行逆行灌注.基本灌流液(溶液A),是用纯水和高纯度试剂制备,其成分有(mmol·L-1):NaCl130;HEPES23;葡萄糖21;牛磺酸20;肌酸5;MgCl25;丙酮酸钠5;KCl4.5;NaH2PO41;pH7.3.过滤(0.2μm滤纸片)溶液除去微生物和水颗粒.A溶液是分离过程中使用的其他4种溶液的原料:1750μmol·L-1Ca2+溶液(300mLA溶液+750μmol·L-1Ca2+);2游离Ca2++EGTA…     

Adolescent pregnancy--current trends and issues: 1998 American Academy of Pediatrics Committee on Adolescence, 1998-1999

Although the prevention of unintended adolescent pregnancy is a primary goal of the American Academy of Pediatrics and society, many adolescents continue to become pregnant. Since the last statement on adolescent pregnancy was issued by the Academy in 1989, new observations have been recorded in the literature. The purpose of this new statement is to review current trends and issues on adolescent pregnancy to update practitioners on this topic.     

Analysis with antiidiotype antibody of a patient with chronic lymphocytic leukemia and a large cell lymphoma (Richter's syndrome)

A murine monoclonal antibody made against an idiotypic determinant (Id) of surface IgM/IgD lambda molecules on chronic lymphocytic leukemia (CLL) cells of a 71-year-old woman was used for clonal analysis by two- color immunofluorescence. The anti-Id antibody identified IgM+/IgD+/lambda+ B cells as the predominant cell type of her CLL clone. In addition, substantial proportions of the IgG and IgA B cells and most of the IgM plasma cells in her bone marrow and blood were Id+. Six years after diagnosis, the patient died of respiratory failure due to infiltration of lungs by malignant cells. Autopsy revealed a dramatic change in the tumor cell morphology. The lungs, hilar nodes, and liver were infiltrated by a diffuse large cell lymphoma admixed with the leukemic cells. By immunohistologic staining these anaplastic lymphoma cells were IgM+/IgD-/lambda+ B cells expressing the same Id noted earlier on the CLL cells. The immunoglobulin gene rearrangement pattern on Southern blot analysis was also the same in leukemic blood cells and in the tissues involved by the lymphoma. Thus, the combination of antiidiotype and immunoglobulin gene analyses in this patient with Richter's syndrome revealed that a CLL clone, seemingly "frozen" in differentiation, was actually undergoing isotype switching, differentiation into plasma cells, and evolution into a rapidly growing and fetal lymphoma.     

Insulin-like growth factor-1 potentiates expansion of interleukin-7- dependent pro-B cells

Commitment to B-lymphocyte differentiation is characterized by expression of the B220 form of the common leukocyte antigen (Ly-5) and D-JH rearrangement of the Ig heavy chain gene complex. B-lineage progenitor cells, or pro-B cells, that have initiated Ig gene rearrangement, but do not express detectable Ig heavy or light chain protein, have recently been shown to retain substantial capacity for expansion in vitro in the presence of bone marrow (BM) stromal cells and interleukin-7 (IL-7). Although the potentiating effect of stromal cells on pro-B-cell proliferation can be partially attributed to the ligand for the proto-oncogene receptor c-kit (c-kit ligand [KL] or stem cell factor), several lines of evidence suggest that c-kit-mediated cell signalling is not required for pro-B-cell expansion. Previous studies from this laboratory demonstrated that insulin-like growth factor-1 (IGF-1) potentiated the proliferative effect of IL-7 on nonadherent cells from lymphoid long-term BM cultures in a manner similar to that shown for KL. To further delineate specific cell stages that respond to lymphopoietic cytokines, we derived continuously proliferating pro-B-cell lines from day-14 murine fetal liver in the presence of IL-7 and BM stromal cell clone S10. Initial expansion and continued proliferation of these pro-B-cell lines was absolutely dependent on the presence of both IL-7 and stromal cells. In the absence of KL, IL-7-stimulated proliferation of these cells in short- term cultures and addition of either recombinant IGF-1 or KL significantly potentiated this proliferative response. Although IGF-2 and insulin also potentiated the effect of IL-7, our data suggest that neither IGF-2 nor insulin represent normal regulators of intramyeloid lymphocyte development. IGF-1 and KL activate unique cascades of intracellular signalling events and inclusion of both cytokines in cultures of IL-7-stimulated pro-B cells resulted in additive potentiation of the proliferative response. Taken together, these results suggest that expansion of pro-B cells in vivo is maintained by at least three stromal cell-derived cytokines. IL-7 appears to be unique in delivering the primary proliferative signal for pro-B-cell expansion; however, both KL and IGF-1 potentiate the proliferative effect of IL-7 on these cells. The functional redundancy and additive effects of IGF-1 and KL as amplification signals for developing B- lineage cells underscore the essential nature of clonal expansion and diversification in development of immunocompetent lymphoid cells.