CO2 dissociation curves of oxygenated whole blood obtained at rest and in exercise

Summary In vitro CO₂ dissociation curves for oxygenated whole blood were determined in 19 healthy male subjects at rest and during submaximal and maximal bicycle work. Hemoglobin concentration and blood lactate increased with increasing work load and accordingly buffer value of the whole blood increased while bicarbonate and Base Excess (BE) decreased, resulting in a downward shift of the CO₂ dissociation curve during exercise. Despite the marked increase in buffer values of the blood, the slopes of the CO₂ dissociation curves during exercise were found to be about the same as those obtained at rest. It was inferred that the increasing effect of increased buffer value, on the dissociation slope, was essentially compensated by the decreasing effect of diminished bicarbonate content. The advantages of this relatively constant CO₂ dissociation slope for the indirect measurement of cardiac output by the Fick principle are discussed.     

Axonal trajectory of single group Ia and Ib fibers in the cat spinal cord

Intracellular staining with HRP of physiologically identified group Ia and Ib afferent fibers in the adult cat lumbosacral cord revealed that group Ia and Ib fibers take a similar course in the dorsal funiculus, but the collaterals emerging from them show a different topographical distribution and a different mode of branching in the gray matter. Ia collaterals terminate in laminae VI, VII, IX, and sometimes VIII, whereas Ib collaterals terminate only in lamina VI, or both VI and IX. In lamina IX, two large motor-type neurons received terminations of both Ia and Ib fibers at the same time.     

Penicillin-specific antibodies: Monoclonals versus polyclonals in ELISA and in an optical biosensor

Two penicillin-specific monoclonal antibodies mAb 19C9 and mAb 9H3 and the penicillin-specific polyclonal antibodies pAb K2 were evaluated for their use in a competitive ELISA and in the BIAcore™ optical biosensor. In the ELISA, an ampicillin-protein conjugate was used as a coating molecule. For the biosensor assay, ampicillin was immobilized on a CM5 chip. With both monoclonal antibodies and in both test systems, ampicillin, amoxicillin and benzylpenicillin were better recognized than oxacillin, cloxacillin and dicloxacillin. Because the reproducibility was better in the biosensor (CV = 1.6%) than in the ELISA (CV = 8.9%), the limit of detection for ampicillin in buffer solution using mAb 19C9 was lower in the biosensor (46 ng ml^-1) as compared to the ELISA (356 ng ml^-1). Ampicillin can thus be detected below the MRL (50 ng ml^-1) in the biosensor assay but not in the ELISA. Both the ELISA and biosensor assay using the polyclonal antibodies pAb K2 were more sensitive as compared to the assays with the monoclonals. The ELISA using pAb K2 allowed the detection of all tested penicillins below the MRL. In the biosensor assay, ampicillin was also detected below the MRL (IC50 = 10 ng ml^-1). In contrast to the binding of the monoclonals, no spontaneous dissociation was observed after injection of the polyclonal antibodies in the biosensor. Whereas the monoclonals were completely removed from the sensor surface using ampicillin in the buffer solution as regeneration solution, stronger conditions were necessary for the pAb binding.     

Serum progesterone at the time of human chorionic gonadotrophin does not predict pregnancy in in-vitro fertilization and embryo transfer

Controversy exists as to whether the serum concentration ofprogesterone on the day of human chorionic gonadotrophin (HCG)administration following ovarian stimulation for in-vitro fertilization(IVF) and embryo transfer can be used to predict the likelihoodof success. This retrospective study was undertaken to answerthis question by analysing a large population of IVF and embryotransfer cycles (n = 756). In addition to the concentrationof progesterone on the day of HCG administration, all variablesknown to impact on IVF and embryo transfer success (such aspatient age), indication for IVF and embryo transfer, numberof oocytes retrieved and the number of embryos generated andtransferred were examined. There was a significant increasein the number of oocytes retrieved with increasing progesteroneconcentration at the time of HCG administration. However, therewas no correlation of progesterone concentration at HCG administrationwith pregnancy and implantation rates. It is concluded thatprevious reports associating a slight elevation of progesteronein gonadotrophin- releasing hormone agonist ovarian stimulationcycles for IVF and embryo transfer may be misleading becauseof a small sample size or the presence of confounding variablesthat affect IVF and embryo transfer success.     

Effects of fibrinogen on lipid peroxidation in patients with coronary heart disease and in vitro

In patients with coronary heart disease oxidizability of lipids during Cu²⁺-induced oxidation of blood plasma inversely correlated with fibrinogen content. A positive correlation was found between the amount of lipid peroxidation products in the plasma from these patients and fibrinogen content. The increase in fibrinogen content was associated with high levels of total lipids and triglycerides and low concentration of high-density lipoprotein cholesterol. In vitro experiments demonstrated that fibrinogen reduces oxidizability of blood plasma. Our results suggest that the decrease in lipid oxidizability at high concentration of fibrinogen in patients with coronary heart disease is related to predominant oxidation of fibrinogen and its competition with plasma lipids during Cu²⁺-induced oxidation.     

Membrane orientation of the precursor 74-kDa form of L-histidine decarboxylase

Objective We previously demonstrated that, when expressed in COS-7 cells, L-histidine decarboxylase (HDC), which has neither an amino terminal signal sequence nor a hydrophobic membrane anchor, was localized in the endoplasmic reticulum (ER), although its orientation in the membrane remains to be clarified. Methods & Results Protease digestion and immunofluorescence analyses of the cells, of which plasma membrane was selectively permeabilized, revealed that the amino terminal 50-kDa portion of HDC is hardly accessible to proteases and antibodies added exogenously from the cytosolic side. Green fluorescent protein fused with the carboxyl terminal 20-kDa region of HDC at its carboxyl terminus exhibited the same characteristics as native HDC. Conclusion These results indicate that HDC is tightly associated with the ER membrane with its carboxyl terminal region exposed on the cytosolic side. Received 22 November 2005; returned for revision 28 December 2005; accepted by A. Falus 22 January 2006     

Endometriosis: a dysfunction and disease of the archimetra

Endometriosis is considered primarily a disease of the endometrial-subendometrial unit or archimetra. The clinical picture of endometriosis characterises this disease as a hyperactivation of genuine archimetrial functions such as proliferation, inflammatory defence and peristalsis. While the aetiology of the disease remains to be elucidated, a key event appears to consist in the local production of extraovarian oestrogen by a pathological expression of the P450 aromatase. The starting event may consist in a hyperactivity of the endometrial inflammatory defence, a hyperactivity of the endometrial oxytocin/oxytocin receptor system or in the pathological expression of the P450 aromatase system itself. Regardless of which of these levels the starting event is localized in, they influence each other on both the level of the archimetra and the endometriotic lesions. Locally elevated oestrogen levels inevitably up-regulate the endometrial oxytocin mRNA and increased levels of oxytocin result in uterine hyperperistalsis, increased transtubal seeding of endometrial tissue fragments and finally subfertility and infertility by impairment of the uterine mechanism of rapid and sustained sperm transport. Locally increased levels of oestrogen lead, on both the level of the endometrial-subendometrial unit and the endometriotic lesion, to processes of hyperproliferation. These processes result, on the level of the uterus, in an infiltrative growth of elements of the archimetra into the neometra and, on the level of the endometriotic lesion, in infiltrative endometriosis. There is circumstantial evidence that trauma might be an important initial event that induces the specific biochemical and cellular responses of the archimetra. This model is able to explain both the pleiomorphic appearance of endometriosis and the, up until now, enigmatic infertility associated with mild and moderate endometriosis.     

Serosal mesothelium retains vasculogenic potential.

Mesothelia comprise the epithelial covering of coelomic organs and line the cavities in which they are housed. Mesothelia contribute to the vasculature of the heart and the intestinal tract by developmental processes of epithelial-mesenchymal transition (EMT), migration, and differentiation into endothelial cells, vascular smooth muscle cells, and pericytes. Here, we establish a novel in vitro system to analyze the differentiative potential of mesothelia. Using explants from serosal mesothelium (the mesothelial covering of the gut), we demonstrate that much of the developmental program observed in embryonic mesothelia is retained in the adult structure. Namely, processes of epithelial spreading, EMT, and differentiation into smooth muscle cells from these cells are observed. Interestingly, we were unable to stimulate endothelial cell differentiation using serum or various signaling factors. Taken together, these data reveal that differentiated serosal cells retain vasculogenic potential and provide a generalizable model for future studies on the developmental and differentiative capacity of the mesothelial cell type.     

大鼠孤束核内NT-LI成分生后发育和衰老变化的光镜和电镜观察

用免疫细胞化学和电镜相结合技术,在光镜和电镜水平对生后4天、15天、30天、90天、300天和760天6组大鼠孤束核内神经降压肽样免疫反应(NT-LI)成分的生后发育和衰老变化进行了定量研究。光镜下孤束核内NT-LI胞体和终末主要分布于最后区平面,多见于背侧亚核、内侧亚核和连合核内。电镜下内侧亚核内可见NT-LI胞体、树突、轴突及终末。6组大鼠孤束核内NT-LI细胞均数和内侧亚核内NT-LI终末密度及其突触密度均以生后4天至15天间增长最快,NT-LI细胞数在生后15天达到最高,NT-LI终末及突触密度在生后90天达到最高。三者在生后300天时均明显减少。发育期内侧亚核内NT-LI终末构成的突触以Gray Ⅰ型为主,至老年期则变为Gray Ⅱ型占优势。发育期内侧亚核内以含清亮囊泡伴颗粒囊泡的NT-LI终末为主,老年期此类终末明显减少。只含清亮囊泡的NT-LI终末从生后至老年变化不明显。