兔骨髓基质细胞诱导分化为胰岛素分泌细胞的方法

目的 探讨将骨髓基质细胞（MSCs）诱导成为胰岛素分泌细胞（IPCs）的方法。方法 体外培养新西兰兔骨髓及胰腺基质细胞和SD大鼠胰腺基质细胞，利用含有胰腺基质细胞培养基的混合培养基诱导培养MSCs。结果 以兔及SD大鼠胰腺基质细胞培养基均可诱导兔MSCs生成IPCs。结论 兔及SD大鼠的胰腺基质细胞培养基均可将兔MSCs诱导分化为IPCs。     

外伤性脾切除术后中医证候及免疫功能的研究

目的:研究外伤性脾切除术后中医辨证与免疫功能变化的关系.方法:选择15例脾切除和15例非脾切除患者作为观察对象,以其症状、舌苔、脉象及免疫功能的测定作为观察指标,观察其中医辨证与免疫功能变化.结果:脾切除组在术后早期可出现脾胃虚弱的证候群,同时免疫功能测定补体C3、免疫球蛋白IgG、免疫球蛋白IgM的水平明显降低,与非脾切除组有显著性差异.结论:脾切除容易造成患者术后出现的脾胃虚弱症候群,并降低患者的免疫功能.     

体外细胞培养检验“方证对应”关系的方法学研究

目的通过在体外细胞培养中加入中药复方粗提制剂对具有典型的中医证型的肺癌患者的外周血淋巴细胞NK活性的影响，探索能否在体外实验中反映“方证对应”关系。方法以水煎醇沉法制备两种中药复方（益气养阴和健脾化痰）的粗提制剂，取具有典型的中医证型（气阴两虚或脾虚痰湿证型）的肺癌患者的外周血淋巴细胞，将同一个患者的标本分为四个体外实验组，即空白对照组，中药5mg／ml组及10mg／ml组，自细胞介素2（250^u/ml，阳性对照）组。按“辨证论治”原则加入相应的中药复方制剂。体外培养22h或94h，以MTT法检测各组的NK活性。结果无论培养22h或94h，中药组的NK活性与对照组比较皆无显著性差异（P〉0．05），而白细胞介素2（阳性对照）组的NK括性均明显升高（P〈0．05）。结论两种中药复方制剂都未能在体外反应出“方证对应”的效果，说明中药粗提制剂直接用于体外细胞培养，其结果的可靠性差。     

The end adjusts the means: Heterochromatin remodelling during terminal cell differentiation

All cells that constitute mature tissues in an eukaryotic organism undergo a multistep process of cell differentiation. At the terminal stage of this process, cells either cease to proliferate forever or rest for a very long period of time. During terminal differentiation, most of the genes that are required for cell ‘housekeeping’ functions, such as proto-oncogenes and other cell-cycle and cell proliferation genes, become stably repressed. At the same time, nuclear chromatin undergoes dramatic morphological and structural changes at the higher-order levels of chromatin organization. These changes involve both constitutively inactive chromosomal regions (constitutive heterochromatin) and the formerly active genes that become silenced and structurally modified to form facultative heterochromatin. Here we approach terminal cell differentiation as a unique system that allows us to combine biochemical, ultrastructural and molecular genetic techniques to study the relationship between the hierarchy of chromatin higher-order structures in the nucleus and its function(s) in dynamic packing of genetic material in a form that remains amenable to regulation of gene activity and other DNA-dependent cellular processes.     

Leukaemia Inhibitory Factor or Related Factors Promote the Differentiation of Neuronal and Astrocytic Precursors within the Developing Murine Spinal Cord

Previously we have shown that leukaemia inhibitory factor (LIF) potentiates the development of murine spinal cord neurons in vitro , suggesting that it, or related factors, may play an important regulatory role in neuronal development. We have further investigated this role and show here that the generation of neurons in cultures of embryonic day 10 spinal cord cells is inhibited by antibodies to the β subunit of the LIF receptor. Since there are more undifferentiated precursors in antibody-treated cultures than in control and LIF-treated cultures, it is concluded that the primary action of LIF, or related molecules, is to promote neuronal differentiation, not precursor survival. In addition, the failure of LIF to support neuronal survival in the period immediately following differentiation suggests that the increased numbers of neurons generated with LIF are not attributable to its neurotrophic action. By selecting neuronal precursors on the basis of their inability to express class I major histocompatibility complex molecules, it was shown that LIF acted directly upon these cells and not via an intermediary cell. LIF also appears to be involved in regulating the differentiation of astrocytes, since it increases the number of glial fibrillary protein (GFAP)-positive cells present in the cultures and since the spontaneous production of GFAP-positive cells is blocked by antibodies to the LIF β receptor. These findings suggest that LIF or related factors promote the differentiation of neural precursors in the spinal cord, but that they are not involved in preferentially promoting precursors down a specific differentiation pathway.     

The multifunctionality of FGF-2 in the adrenal medulla

 Chromaffin cells of the adrenal medulla and their tumor counterparts, the pheochromocytoma (PC12) cells, are well-established model systems in neurobiology. The development of sympathoadrenal progenitor cells to chromaffin cells can be studied with regard to developmental signals which trigger the differentiation. With regard to potential treatments of neurological disorders like Parkinson’s disease chromaffin cell grafting can be used as one therapeutical approach. The beneficial effect of chromaffin cell grafts is possibly not only related to the release of dopamine but may also be linked to the release of growth factors. One of the growth factors that is synthesized by chromaffin and PC12 cells is basic fibroblast growth factor (FGF-2). The experimental data available so far, are in agreement with different functional roles of FGF-2. This article summarizes the putative physiological functions of FGF-2 in the adrenal medulla. Three differential functional roles of FGF-2 are discussed: (1) as a differentiation factor for sympathoadrenal progenitor cells; (2) as a target-derived neurotrophic factor for preganglionic sympathetic neurons which innervate adrenal medullary cells; (3) as an auto-/paracrine factor in the adrenal medulla. Accepted: 21 August 1996     

Characterization and phenotypic analysis of differentiating CD34+human bone marrow cells in liquid culture

Abstract: Our current understanding of human haematopoietic stem cell biology is based in part on the characterization of human CD34⁺ bone marrow cell differentiation in vitro. CD34 is highly expressed on early stem cells and haematopoietic progenitor cells with clonogenic potential and is gradually lost during differentiation and commitment. However, CD71 (transferrin receptor) is expressed at low levels on early stem cells and generally increases during haematopoietic progenitor cell proliferation. We reasoned that the combination of these surface markers would provide a useful framework for the simultaneous analysis of multiple lineage differentiation of CD34⁺ haematopoietic progenitor cells in liquid culture. In this report, we identify the phenotype of distinct subpopulations of myeloid, erythroid and lymphoid cells in liquid suspension culture using differential expression of CD34 vs. CD71 in combination with specific lineage markers. Freshly isolated human CD34⁺ bone marrow cells were introduced into suspension culture and monitored over a 6-d period using 3-colour flow cytometry. This is the first demonstration that differential expression of CD34 vs. CD71 can be used to simultaneously monitor differentiation of multiple haematopoietic cell lineages in liquid suspension culture, facilitating the study of cytokine-, drug- or chemical-induced alterations in haematopoietic progenitor cell differentiation in vitro.     

Neonatal exposure to estradiol prevents the expression of ovarian hormone-induced luteinizing hormone and prolactin surges in adulthood but not antecedent changes in neuropeptide Y or adrenergic transmitter activity: Implications for sexual differentiation of gonadotropin secretion

Sex differences in adult patterns of mating behavior and gonadotropin secretion in rats are determined in part by the presence or absence of gonadal steroids during a perinatal critical period. For example, male rats and female rats exposed neonatally to androgen do not exhibit LH surge patterns when treated appropriately with ovarian hormones in adulthood, and there is evidence that this may be due to a failure of ovarian hormones to activate the hypothalamic neuronal systems that stimulate LH secretion in such animals. Because considerable evidence suggests that estradiol formed centrally from testosterone is responsible for the permanent defeminization of mating behavior and gonadotropin secretion, the present studies compared normal females with normal males and with females treated neonatally with estradiol on the ability of ovarian hormones to induce several important neurochemical changes antecedent to the LH surge, including changes in neuropeptide Y (NPY) and LH-releasing hormone (LHRH) concentrations in the median eminence, as well as changes in turnover rates for catecholamine transmitters in the medial basal hypothalamus and medial preoptic area. Normal ovariectomized female rats responded to sequential treatment with estradiol followed by progesterone with afternoon LH and prolactin (PRL) surges, and with sequential accumulation followed by decline in concentrations of LHRH and NPY in the median eminence prior to the LH surge. In addition, administration of progesterone increased the turnover rates of norepinephrine (NE) and epinephrine (EPI) in the arcuate-median eminence region of normal females. Gonadectomized male rats receiving the same ovarian hormone treatment failed to exhibit LH or PRL surges and displayed none of the changes in neurotransmitter turnover or peptide concentrations characteristically seen in the normal female. Unexpectedly however, when females that were treated with estradiol benzoate on days 1–3 postpartum were ovariectomized and treated with ovarian hormones in adulthood, they showed the same accumulation/decline in median eminence NPY concentrations and the same activation of NE and EPI turnover in the arcuate-median eminence region as normal females, even though they showed no LH or PRL surges or changes in median eminence LHRH concentrations. These results suggest that estradiol may not mediate all of the defeminizing actions of androgen exerted during the early neonatal period, and particularly those actions that result in a lack of responsiveness in central noradrenergic, adrenergic and NPY systems in adulthood. However, an action of neonatal estradiol may result in uncoupling of the LHRH neurosecretory system from normal excitatory neurochemical influences.     

Liposomal 1,25 (OH)2 vitamin D3 compounds block proliferation and induce differentiation in myelomonocytic leukaemia cells

The vitamin D₃ derived hormone 1,25 (OH)₂ vitamin D₃ (1,25 D₃) is able to induce growth arrest and differentiation in myelomonocytic leukaemia cells. In order to allow for specific delivery to leukaemic cells the lipophilic compound was incorporated into the lipid membranes of liposomes. Liposomal 1,25 D₃ reduced proliferation as measured by ³H-thymidine incorporation in HL60 leukaemia cells by up to 60%. When liposomes were prepared at different concentrations of 1,25 D₃ 65% inhibition was achieved at 48 n M . The MC 1288 stereoisomer of 1,25 D₃ was more potent and had the same activity at 48 n M .
The effect of the liposomal compounds was specific to myeloid cells as they reduced proliferation in myelomonocytic HL60, monoblastic U937 and monocytic Mono Mac 6 cells but not in the T-cell lines Jurkat and Molt 4.
The antiproliferative effect of liposomal 1,25 D₃ was associated with an induction of differentiation since treated HL60 cells showed a monocytic morphology, increased expression of CD14 and decreased expression of CD33.
When peripheral blood leukaemic cells from M4 and M5 acute myeloid leukaemia (AML) patients were admixed with liposomal compounds an antiproliferative effect was seen in all five cases, including the two cases where free compounds led to enhanced growth. Liposomal delivery of 1,25 (OH)₂ vitamin D₃ may offer a novel approach to treatment of myelomonocytic leukaemia.     

HMBA诱导MEC—1细胞分化角蛋白染色的变化

用六亚甲基二乙酰胺（ＨＭＢＡ）作为分化诱导剂，对人粘液表皮样癌细胞系ＭＥＣ－１细胞中角蛋白进行染色，结果发现高分子量角蛋白在被诱导细胞中含量明显增高。分光光度仪检测角蛋白含量，诱导组ｘ±ｓ为２１８±５１，对照组为１４９±４７，两组有显著差异（Ｐ＜００１），这可能与细胞分化有关。