Specific staining of the axon membrane at nodes of Ranvier with ferric ion and ferrocyanide

Ferric ion and ferrocyanide were used as stains for light and electron microscopy of peripheral nerves. In rat sciatic nerves, it was found that ferric ion preferentially binds to the cytoplasmic surface of the axon membrane at nodes of Ranvier but not at internodal regions. In myelinated axons in the electric organ of the gymnotid fish, Sternarchus albifrons, the small excitable nodes are similarly stained, but the larger inexcitable nodes are not stained by ferric ion. Staining of the inner surface of the nodal membrane appears to be related to a structural specialization of this membrane, rather than accessibility to stain. Our data thus show a chemical differentiation of the inner surface of the axon membrane between nodes and internodes in normal peripheral nerve fibers and between the inner surface of the axon membrane at active nodes, inactive nodes, and the internodes in the Sternarchus electrocyte axons.     

G protein-mediated receptor-receptor interaction: studies with chemotactic receptors in membranes of human leukemia (HL 60) cells

Summary Differentiated human leukemia (HL 60) cells contain high numbers of receptors for the chemotactic factors, N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe) and complement component 5a (C5a), both coupled to pertussis toxin-sensitive guanine nucleotide-binding regulatory proteins (G proteins). Agonist activation of either receptor stimulated binding of the GTP analog, guanosine 5-[-thio]triphosphate (GTP[S]), to membrane G proteins and by a similar extent in a non-additive manner. The possible interaction of the two receptors was studied by measuring agonist binding to one receptor in the presence of the other receptor agonist. fMet-Leu-Phe and C5a had no effects on [¹²⁵I]C5a and fMet-Leu-[³H]Phe receptor binding, respectively, when studied in the absence of regulatory ligands. Similarly, the inhibitory effects of NaCl and GDP on agonist receptor binding were not altered in the presence of the other receptor agonist. In contrast, in the presence of the GTP analogs, GTP[S] and guanosine 5-[,-imino] triphosphate, fMet-Leu-Phe and C5a reduced the binding of [¹²⁵I]C5a and fMet-Leu-[³H]Phe, respectively, in a concentration-dependent manner. The potencies of the GTP analogs to inhibit binding of [¹²⁵I]C5a and fMet-Leu-[³H]Phe was increased about 3-fold by fMet-Leu-Phe and C5a, respectively. The data presented suggest that fMet-Leu-Phe and C5a receptors share the same G protein pool in membranes of HL 60 cells and that activation of these G proteins by one of the two receptors decreases the availability of G proteins for the other receptor. Correspondence to T. Wieland at the above address     

Comparative patterns of i-antigen expression, F-cell frequency and Hb A2 level in acute myeloid leukemia and in acute lymphoid leukemia

Hb F, Hb A₂ and i-antigen expression were investigated in adulthood acute leukemias. The study of i-antigen expression by immuno-agglutination and immunofluorescence showed that it is preferentially increased among AML patients. A similar result was obtained for F-cell frequency which was often increased in AML, while it was normal in ALL. Hb A₂ level was significantly lower in AML than in ALL. These differences between AML and ALL red cell patterns further suggest that the leukemic clone involves the erythroid lineage in AML but not in ALL.     

母儿血型不合IgG抗体效价≥1：512是否提示胎儿病情严重

目的：探讨母儿血型不合IgG抗体效价≥1：512是否提示胎儿病情严重。方法：对6例血清IgG抗A（B）抗体效价≥1：512的母儿血型不合孕妇，进行羊膜腔穿刺抽样羊水作胆红素、IgG抗体效价和胎儿血型物质测定，抽取其新生儿脐血作胎儿血型、胆红素检测及Coombs试验。结果：孕妇血清IgG抗体效价与新生儿溶血病的严重程度并不密切相关。结论：不能单纯以孕妇血清抗体效价的高低作为判断胎儿溶血的唯一依据。     

An inhibitor of glycinamide ribonucleotide formyltransferase is selectively cytotoxic to cells that lack a functional G1 checkpoint

Purpose: We studied the effects of purine depletion on the cell cycle using a specific inhibitor of de novo purine biosynthesis, AG2034, an inhibitor of glycinamide ribonucleotide formyltransferase (GARFT). Methods: Cytotoxicity was determined by clonogenic assays, and cell cycle perturbations by flow cytometry. Ribonucleotide pools were measured by anion exchange high-pressure liquid chromatography, and DNA strand-breaks were determined by alkaline elution and by the TUNEL assay. Results: When cells were maintained in standard tissue culture medium, which contained 2.2 μM folic acid, AG2034 was cytostatic in all the cell lines tested. Under low-folate conditions (50 nM folic acid), AG2034 caused up to 50% cell death in cell lines that possessed a functional G1 checkpoint (A549, MCF-7), but was only cytostatic to the remaining cells, even at very high concentrations (100 μM ). In contrast, AG2034 at 10 nM or 100 nM killed all the cells in cultures of HeLa/S3 or SW480 cells, which lack a functional G1 checkpoint. Flow cytometry studies indicated that in G1 checkpoint-competent cells, AG2034 caused a G1 arrest. Those cells (up to 50%) that were already in S phase died, but the cells that were in G1 arrest maintained viability, based upon clonogenic assays, for many days. In G1 checkpoint-deficient cells, no G1 arrest was seen after AG2034 treatment, all cells progressed into S phase, and all cells died. Measurement of DNA strand-breaks, either by alkaline elution or by the dUTP end-labelling technique, indicated no DNA strand-breaks 24 h after AG2034 treatment, indicating that purine nucleotide depletion can trigger the G1 checkpoint in the absence of DNA damage. Conclusion: Purine depletion causes slow cell death in cells that have passed the G1 checkpoint, but cytostasis in cells that are arrested at the G1 checkpoint. The GARFT inhibitor, at physiological folate concentrations, thus causes selective cytotoxicity to cells lacking a functional G1 checkpoint. Received: 8 May 1997 / Accepted: 26 June 1997     

Immunoglobulin G subclasses in wheezing infants

Background: The wheezing infant is a common but difficult patient to approach diagnostically. The prevalence of immunoglobulin (Ig) G subclass deficiency in wheezing infants is still controversial. Methods: We studied the serum concentration of IgG subclasses in 38 wheezing infants (aged6–24 months) who had not received systemic steroids before investigation and in 30 healthy age matched controls6–31 months). Results: The prevalence of one or more IgG subclass deficiencies was 3 1.6% in wheezing infants and 26.7% in controls. There was no significant difference in prevalence of IgG subclass deficiency between patients and controls (P > 0.05). The mean concentration of IgG subclasses in patients were compared with controls. There was no significant difference in mean serum concentration of IgG₁, G₂ and G₃ subclasses. However, there a trend towards higher concentrations of IgG₄ in wheezing infants and this difference for IgG₅ was significant (P < 0.01). Immunoglobulin G subclass deficiency was found in 25 and 36.4% of wheezing infants who experienced from two to four and five or more wheezing episodes in 2 years, respectively (P > 0.05). Conclusion: Our findings suggest that wheezing in infancy is not associated with IgG subclass deficiency, and in wheezing infants low IgG subclasses levels do not increase the frequency of wheezing. However, is a relationship between recurrent wheezing and serum IgG₄ subclass concentration.     

A novel brain receptor is expressed in a distinct population of olfactory sensory neurons

Three novel G-protein-coupled receptor genes related to the previously described RA1c gene have been isolated from the mouse genome. Expression of these genes has been detected in distinct areas of the brain and also in the olfactory epithelium of the nose. Developmental studies revealed a differential onset of expression: in the brain at embryonic stage 17, in the olfactory system at stage E12. In order to determine which cell type in the olfactory epithelium expresses this unique receptor type, a transgenic approach was employed which allowed a coexpression of histological markers together with the receptor and thus visualization of the appropriate cell population. It was found that the receptor-expressing cells were located very close to the basal membrane of the epithelium; however, the cells extended a dendritic process to the epithelial surface and their axons projected into the main olfactory bulb where they converged onto two or three glomeruli in the dorsal and posterior region of the bulb. Thus, these data provide evidence that this unique type of receptor is expressed in mature olfactory neurons and suggests that it may be involved in the detection of special odour molecules.     

CCL2-2518λ������̬������֢��������71�͸�Ⱦ������о�

??Objective To investigate the relationship between CCL2-2518A/G gene polymorphism and severity of enterovirus 71??EV71?? infection. Methods CCL2 gene polymorphism in 188 EV71-infected patients and 235 healthy controls were detected by the improved multiplex ligation detection reaction technique??iMLDR??. The level of CCL2 in two groups was determined by enzyme-linked immunosorbent assay??ELISA??. Results No significant differences were found in the distribution of genotype CCL2-2518A/G between EV71-infected patients and the healthy control group??P??0.05??. The G allele??genotypes AG or GG?? in the CCL2-2518A/G??P??0.001?? was more frequent in patients with severe EV71 infection. The level of CCL2 in infected patients was higher than that of the heathy controls ??P??0.05???? the severe cases had higher level of CCL2 than that of the slight cases and healthy controls??P??0.05??. The level of CCL2 in GG gene group was significantly higher than that in AG gene group and the level of CCL2 in AG gene group was significantly higher than that in AA gene group.The people with CCL2-2518G allele??GG+AG?? had higher level of CCL2 than those only with CCL2-2518A allele??AA????P??0.05??. Conclusion The G carrier of the CCL2-2518A/G is found to be associated with severity of EV71 infection??and could be susceptibility factors in the development of EV71 infection.     

乳状液膜法提取青霉素非稳态传质数学模型的研究

在“渐进前沿模型”的基础上 ,建立并推导了乳状液膜法提取青霉素的非稳态传质数学模型。实验条件下乳状液膜法提取青霉素的过程属扩散控制 ,其阻力主要来源于膜相。青霉素在膜相中的扩散是提取过程的速控步骤     

Cyanidin-3-O-glucoside and Peonidin-3-O-glucoside-Rich Fraction of Black Rice Germ and Bran Suppresses Inflammatory Responses from SARS-CoV-2 Spike Glycoprotein S1-Induction In Vitro in A549 Lung Cells and THP-1 Macrophages via Inhibition of the NLRP3 Inflammasome Pathway

Black rice is a functional food that is high in anthocyanin content, primarily C3G and P3G. It possesses nutraceutical properties that exhibit a range of beneficial effects on human health. Currently, the spike glycoprotein S1 subunit of SARS-CoV-2 (SP) has been reported for its contribution to pathological inflammatory responses in targeting lung tissue and innate immune cells during COVID-19 infection and in the long-COVID phenomenon. Our objectives focused on the health benefits of the C3G and P3G-rich fraction of black rice germ and bran (BR extract) on the inhibition of inflammatory responses induced by SP, as well as the inhibition of NF-kB activation and the NLRP3 inflammasome pathway in an in vitro model. In this study, BR extract was identified for its active anthocyanins, C3G and P3G, using the HPLC technique. A549-lung cells and differentiated THP-1 macrophages were treated with BR extract, C3G, or P3G prior to exposure to 100 ng/mL of SP. Their anti-inflammatory properties were then determined. BR extract at concentrations of 12.5–100 μg/mL exhibited anti-inflammation activity for both A549 and THP-1 cells through the significant suppression of NLRP3, IL-1β, and IL-18 inflammatory gene expressions and IL-6, IL-1β, and IL-18 cytokine secretions in a dose-dependent manner (p < 0.05). It was determined that both cell lines, C3G and P3G (at 1.25–10 μg/mL), were compatibly responsible for the significant inhibition of SP-induced inflammatory responses for both gene and protein levels (p < 0.05). With regard to the anti-inflammation mechanism, BR extract, C3G, and P3G could attenuate SP-induced inflammation via counteraction with NF-kB activation and downregulation of the inflammasome-dependent inflammatory pathway proteins (NLRP3, ASC, and capase-1). Overall, the protective effects of anthocyanins obtained from black rice germ and bran can be employed in potentially preventive strategies that use pigmented rice against the long-term sequelae of COVID-19 infection.