Expression of the brain creatine kinase gene in rat RT4 peripheral neurotumor cell lines and its modulation by cell confluence

Creatine kinases (CK) catalyze the reversible transfer of a high energy phosphate group between creatine phosphate and ADP to regenerate ATP in cell types where the requirements for ATP are extensive and/or sudden. Previously, we have shown in primary rat brain cell cultures that brain CK (CKB) mRNA levels are highest in astrocytes and oligodendrocytes and much lower in neuronal cells. However, little is known of the factors which regulate CKB expression in the central nervous system and peripheral nervous system. To begin to investigate these factors, we asked in this report (1) if this pattern of CKB expression was also characteristic of some established glial and neuronal cell lines derived from the PNS; (2) whether CKB expression could be rapidly modulated by culture conditions, and (3) if CKB is expressed in cells with characteristics of glial cell progenitors. In subconfluent cells, CKB mRNA and enzyme activity were found to be high in both the rat RT4 peripheral neurotumor stem cell RT4-AC36A and its glial cell derivative RT4-D6. Conversely, CKB mRNA and activity were 5- and 8-fold lower, respectively, in the neuronal derivative RT4-E5 and, more dramatically, CKB was undetectable in neuronal RT4-B8 cells. Maintaining RT4-D6 glial cells at confluence rapidly increased CKB enzyme activity by 7-fold, such that D6 cells contained about 25% of the CKB level in lysates prepared from either whole adult rat brain or primary cultures of rat brain astrocytes. The levels of CKB mRNA and immunoreactive protein were also correspondingly increased in confluent D6 cells. These confluence-mediated increases in CKB appeared to be due to cell-cell contact and not the depletion of serum growth factors or an increase in intracellular cAMP. This study indicates that CKB expression is highest in cells displaying glial properties and can be rapidly modulated by appropriate culture conditions. The results are discussed in relation to the factors which may regulate CKB expression in vivo.     

Polymorphism of pericentromere heterochromatin of polytene chromosomes of ovarian trophocytes in natural populations of the malaria mosquito Anopheles messeae Fall

The HBsAg status and demographic data of 2480 pregnant women who attended antenatal clinics at Maternal and Child Health Centres in Hong Kong were collected by means of a self-administered questionnaire over a 1-week period in July 1996, to explore the underlying reason of a higher than expected HBsAg prevalence. Local women constituted 49.2% of the sample, mainland Chinese 39.7% and others 11.1%. The overall HBsAg prevalence was 10.0%. When related to place of birth, those born in Hong Kong had a prevalence of 8.4% whereas the prevalence of those born in mainland China was 13.1% (P < 0.001). The overall HBsAg carriage rate is high because of a higher rate in immigrants in the community. It is apparent that the HBsAg prevalence of local people in Hong Kong has been decreasing in the past decade. Overall, the current HBsAg carriage rate in the local adult population is estimated to have declined to about 8%.     

Effects of emoxipine and histochrome on lipid peroxidation and activity of serum MB-creatine phosphokinase in patients with ischemic heart disease during aortocoronary shunting]

Comparative study of the cardioprotective effect of antioxidants emoxipin and hystochrom was conducted in patients with chronic ICD during and after operation for aorto-coronary shunting. Both drugs effectively inhibited LPO activation and reduced the reperfusion damage to the myocardium recorded according to the release of MB-PCK into the blood. The new antioxidant hystochrom proved to be more effective. Its prevalent effect is associated with its higher antioxidant activity.     

Population pharmacokinetics of sirolimus in kidney transplant patients

OBJECTIVE: To characterize the dose-related pharmacokinetics of the immunosuppressant agent sirolimus (formerly rapamycin) in kidney transplant patients by use of two-stage and nonlinear mixed-effect model population methods. METHODS: Patients (n = 36) from three centers (Germany, the United Kingdom, and Sweden) who received steady-state oral doses of cyclosporine (ciclosporin) were assessed after single oral administration of sirolimus at doses of 3, 5, 10, and 15 mg/m2. Plasma and whole blood sirolimus samples were analyzed by a high-performance liquid chromatographic/mass spectrophotometric method. Simultaneous fitting used biexponential functions with intercept/slope or clearance/volume terms, as well as first-order absorption (ka) and a lag-time. RESULTS: The nonlinear mixed-effect model method (P-Pharm) provided a better characterization of sirolimus kinetics, especially for the absorption and distribution phases where fewer data were available per patient. Sirolimus distribution between whole blood and plasma was concentration-independent, with a mean blood/plasma ratio (coefficient of variation) of 30.9 (48.5%). Elimination was not influenced by dose, as shown by estimates of the terminal half-life of 63 hours (27.5%) and apparent oral blood clearance of 8.9 L/hr (38.2%). Sirolimus distribution parameters were influenced by body weight and surface area. Sirolimus was rapidly absorbed, as shown by the absorption lag-time of 0.27 hour (35.1%), and ka of 2.77 hr-1 (48.4%). The concomitant administration of sirolimus and cyclosporine did not reveal any pharmacokinetic interactions. CONCLUSION: This report provides an initial population pharmacokinetics of sirolimus in kidney transplant recipients receiving cyclosporine concurrently. Sirolimus blood and plasma pharmacokinetics were biexponential and linear for doses from 3 to 15 mg/m2. No pharmacokinetic interaction was found between sirolimus and cyclosporine.     

Application of the wavelet transform to the problem of the detection and determination of the Lorentzian positions of the 2D band in the Raman spectrum of bilayer graphene

Semiconductors - The possibility of quantifying the number of graphene layers using the integral wavelet transform is shown. The integral wavelet transform is applied to process the 2D band of the...     

Fabrication of CdO–Bi2O3 Ceramics

The phase formation in the CdO-rich part (10 wt % Bi₂O₃) of the CdO–Bi₂O₃ system was studied by x-ray diffraction, IR spectroscopy, electron microscopy, and other techniques. The results indicate that the grinding of the starting powder mixtures in a planetary mill leads to an inhomogeneous Bi₂O₃ distribution and a high defect density in the CdO and Bi₂O₃ particles. Sintering in the range 910–990 K gives rise to the formation of the _h phase, whose content depends strongly on the mixture composition and sintering conditions. At sintering temperatures above its melting point, the _h phase acts as a binder of CdO grains.     

Variations in uterine innervation during the estrous cycle in rat

Uterine innervation undergoes profound remodeling during puberty, pregnancy, and after parturition. However, the extent to which uterine innervation may change during the estrous cycle is uncertain. The objective of the present study was to determine whether nerve fiber density of the uterine horn is altered during the estrous cycle and, if so, which subpopulations are affected. Immunostaining for the pan-neuronal marker protein gene product (PGP) 9.5 revealed fibers within the vascular zone, myometrium, and endometrium, with greater density in the ovarian and cervical regions than in the middle. In most structures, nerve density was reduced during estrus. This could not be accounted for by increased target volume, as the reduction in longitudinal muscle innervation persisted after correction for changes in target size. Immunostaining for vasoactive intestinal polypeptide-immunoreactive parasympathetic nerves revealed fibers associated predominantly with the vascular zone and circular muscle within the cervical region. No cyclical variation was detected. Calcitonin gene-related peptide-immunoreactive nerves were present within all structures, and density was highest at the ovarian end. These fibers also did not vary significantly through estrous. Dopamine beta-hydroxylase-immunoreactive sympathetic nerves innervated all structures, with greater density in the ovarian end. These fibers were reduced substantially during estrus, but the decline was also significant in proestrus, thus preceding that detected by using the pan-neuronal marker. We conclude that the estrous cycle in rat is accompanied by structural remodeling of sympathetic nerves by way of retraction or degeneration of terminal fibers during estrus. The structural loss of the terminal axon apparently is preceded by depletion of catecholamine-synthesizing enzyme.     

A local circuit approach to understanding integration of long-range inputs in primary visual cortex

Integration of inputs by cortical neurons provides the basis for the complex information processing performed in the cerebral cortex. Here, we have examined how primary visual cortical neurons integrate classical and nonclassical receptive field inputs. The effect of nonclassical receptive field stimuli and, correspondingly, of long-range intracortical inputs is known to be context-dependent: the same long-range stimulus can either facilitate or suppress responses, depending on the level of local activation. By constructing a large-scale model of primary visual cortex, we demonstrate that this effect can be understood in terms of the local cortical circuitry. Each receptive field position contributes both excitatory and inhibitory inputs; however, the inhibitory inputs have greater influence when overall receptive field drive is greater. This mechanism also explains contrast-dependent modulations within the classical receptive field, which similarly switch between excitatory and inhibitory. In order to simplify analysis and to explain the fundamental mechanisms of the model, self-contained modules that capture nonlinear local circuit interactions are constructed. This work supports the notion that receptive field integration is the result of local processing within small groups of neurons rather than in single neurons.