Postmitotic marrow neutrophils and neutrophil mobilization in man: role of the spleen

The relationship between postmitotic marrow neutrophils (PMMN) and neutrophil increment in blood after an intravenous dose of 3 mg hydrocortisone/kg was studied in patients with normal-sized spleens and compared with splenectomized and splenomegalic patients. PMMN were quantified from the ferrokinetic measurement of the normoblast number and the PMMN/normoblast ratio in bone marrow biopsy sections. In 12 control patients with normal PMMN the increment was 3.50 +/- 1.13 X 10(9) neutrophils/liter. An excellent correlation was found between the number of PMMN and the maximal neutrophil increment (y = 826x - 1021, r = 0.93, p less than 0.001) among 24 patients with normal spleen size and a wide range of marrow cellularity. Significantly higher responses were observed in 10 splenectomized patients (y = 872x + 1429, r = 0.92, p less than 0.001). The two regression lines were shown to be parallel, indicating a diminution of the response by 2.5 X 10(9) neutrophils/liter in the presence of a normal spleen. In 11 hypersplenic patients the responses were further reduced and more variable. Peak neutrophilia occurred after median values of 2, 3, and 4 hr in the hypersplenic, the control, and the splenectomized group, respectively. These studies indicate that allowing for the different response curves neutrophil increments may be used as an index of PMMN in patients with normal spleen size and in splenectomized patients. They further suggest sequestration of the prematurely released cells by the spleen.     

模拟后路椎间盘镜下腰椎间盘摘除术与传统术式治疗腰椎间盘突出症对腰椎生物力学稳定性的影响

目的探讨后路椎间盘镜下腰椎间盘摘除术(MED)及传统开放腰椎间盘摘除术对腰椎生物力学稳定性的影响。方法选用6具新鲜尸体脊柱标本,模拟后路腰椎间盘摘除的不同术式,依次对标本腰3～4间隙进行处理,共设计5种减压情况:MED、半椎板切除、半椎板切除并下关节突1/2切除、半椎板切除并下关节突全部切除和全椎板切除髓核摘除术。在力学实验机上分别对实验标本进行前屈/后伸、左/右侧屈及左/右轴向旋转运动,测量不同运动的最大范围。结果模拟MED手术脊柱标本向各个方向的运动与正常对照组比较差异无统计学意义(P>0.05);半椎板切除术、半椎板切除并下关节突1/2切除后,标本向各个方向的运动除半椎板切除并下关节突1/2切除后右侧旋转外与正常对照组差异无统计学意义(P>0.05),半椎板切除并下关节突全部切除后,标本向各个方向运动与正常对照组比较差异均有统计学意义(P<0.05,右侧旋转P<0.01);模拟全椎板切除标本向各个方向的运动与正常对照组比较差异均有统计学意义(P<0.01)。结论MED手术对脊柱破坏性较小,对稳定性无影响,而半椎板并小关节切除则破坏了稳定性。     

Interaction between anandamide and sphingosine-1-phosphate in mediating vasorelaxation in rat coronary artery

Background and purpose:

This study establishes a pharmacokinetic/pharmacodynamic (PK/PD) model to describe the time course and in vivo mechanisms of action of the antinociceptive effects of lumiracoxib, evaluated by the thermal hyperalgesia test in rats.

Experimental approach:

Female Wistar fasted rats were injected s.c. with saline or carrageenan in the right hind paw, followed by either 0, 1, 3, 10 or 30 mg·kg⁻¹ of oral lumiracoxib at the time of carrageenan injection (experiment I), or 0, 10 or 30 mg·kg⁻¹ oral lumiracoxib at 4 h after carrageenan injection (experiment II). Antihyperalgesic responses were measured as latency time (LT) to a thermal stimulus. PK/PD modelling of the antinociceptive response was performed using the population approach with NONMEM VI.

Results:

A two-compartment model described the plasma disposition. A first-order model, including lag time and decreased relative bioavailability as a function of the dose, described the absorption process. The response model was: LT=LT₀/(1 +MED). LT₀ is the baseline response, and MED represents the level of inflammatory mediators. The time course of MED was assumed to be equivalent to the predicted profile of COX-2 activity and was modelled according to an indirect response model with a time variant synthesis rate. Drug effects were described as a reversible inhibition of the COX-2 activity. The in vivo estimate of the dissociation equilibrium constant of the COX-2-lumiracoxib complex was 0.24 µg·mL⁻¹.

Conclusions:

The model developed appropriately described the time course of pharmacological responses to lumiracoxib, in terms of its mechanism of action and pharmacokinetics.     

Sequence Specificity of Alternating Hydroyprolyl/phosphono Peptide Nucleic Acids against Zebrafish Embryo mRNAs

Morpholino phosphorodiamidate (MO) DNA mimics display excellent water solubility and hybridization properties toward DNA and RNA, and have been utilized in the model vertebrate zebrafish (Danio rerio) for genome-wide, sequence-based, reverse genetic screens during embryonic development. Peptide nucleic acids (PNAs) exhibit excellent mismatch discrimination, nuclease resistance, and protease resistance, but low solubility. Negatively charged DNA mimics composed of alternating residues of trans-4-hydroxy-L-proline peptide nucleic acid monomers and phosphono peptide nucleic acid monomers (HypNA-pPNA) combine all of the positive features of both MOs and PNAs. Thus, we evaluated PNA oligomers and HypNA-pPNA oligomers as an alternative to MOs for oligonucleotide inhibition of gene expression in zebrafish embryos. We observed that HypNA-pPNA 18-mers displayed comparable potency to MO 25-mers as knockdown agents against chordin, notail and uroD, with greater mismatch stringency. Furthermore, we observed that a specific HypNA-pPNA 18-mer elicited the dharma (bozozok)^-/- phenotype in zebrafish embryos, which MO 25-mers do not. These observations validate HypNA-pPNAs as an alternative to MO oligomers for reverse genetic studies. The stronger hybridization and greater specificity of HypNA-pPNAs enable knockdown of mRNAs unaffected by MO oligomers.     

Function of C3 in a humoral response: iC3b/C3dg bound to an immune complex generated with natural antibody and a primary antigen promotes antigen uptake and the expression of co-stimulatory molecules by all B cells,but only stimulates immunoglobulin synthesis by antigen-specific B cells

Previous studies have shown that an optimal humoral response to a primary protein antigen requires C3 and CR2 (CD21). Sera from non-immunized donors contain natural IgM and IgG antibodies to the primary antigen keyhole limpet haemocyanin (KLH), and these have been previously shown to form immune complexes (IC) that activate the classical pathway of C, fixing iC3b/C3dg onto the KLH antigen. Such KLH IC bind to CR2 on KLH-non-specific B lymphocytes, resulting in antigen processing and MHC class II-dependent presentation to KLH-specific helper T cells. KLH IC also induce B lymphocytes to express the CD80 co-stimulatory molecule via simultaneous CR2 ligation with C3 and FcγRII (CD32) stimulation by IgG natural antibody. The current study demonstrated that KLH IC ligation to either CR2 or FcγRII resulted in activation of a second co-stimulatory molecule, LFA-1 (CD11a, CD18). The possibility of polyclonal B cell stimulation by the presentation of KLH-iC3b/C3dg by antigen-non-specific B cells was excluded by demonstration that in vitro cultivation of peripheral blood mononuclear cells (PBMC) with KLH-iC3b/C3dg elicited only anti-KLH, and did not stimulate synthesis of antibodies to hepatitis C virus (HCV) or tetanus toxoid (TT). Of greatest significance, a specific anti-KLH response was only detectable in cultures stimulated with KLH-iC3b/C3dg and not in cultures stimulated with KLH alone or KLH-IgG. Thus, iC3b/C3dg that was bound to a primary protein antigen enhanced recognition and specific immunoglobulin synthesis by antigen-specific B cells, even though the antigen was taken up and processed via CR2 by both antigen-specific and non-specific B cells.