[Care of "locked"-in syndrome due to cerebrovascular disease].
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Cerebrovascular Disorders↗
Biomedical subjects
D L Wang
Publications and source records attributed to D L Wang.
Clinical application of 131I-HIPDM in the patients with chronic obstructive pulmonary disease.
N,N,N'-trimethyl-N'-2 hydroxy-3-methyl-5-iodobenzyl-1,3-propanediamine iodine-131 (HIPDM) as a lung imaging and metabolic tracer in patients with chronic obstructive pulmonary disease (COPD) were used. 0.4 mCi 131I-HIPDM was rapidly injected into the antecubital vein. The imaging of 131I-HIPDM in the lung was different in various groups. 131I-HIPDM of the clearance by the lungs was a biphasic curve (rapid phase and slow phase). It was displayed that rapid phase of the clearance curve of 131I-HIPDM in the lungs in subjects with chronic obstructive pulmonary emphysema, especially those of smokers were very slow. The rapid phase of the 131I-HIPDM of the right lung clearance was significantly correlated with Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Functional Residual Capacity (FRC), Residual Volume (RV), Total Lung Capacity (TLC) p < 0.01; Peak Expiratory Flow Rate (PEFR), Vital Capacity (VC), Maximum Ventilatory Volume (MVV), Arterial oxygen tension (PaO2) p < 0.05. Smoking influence on clearance of 131I-HIPDM of the lung including normal smokers with normal lung function. It was considered that the analysis of the lung release of 131I-HIPDM forms a new lung dysfunction index and it was useful that found early lung damage.
Adult↗
Prolonged lung retention of 131I-HIPDM in smokers.
Thirty-five subjects were divided into 4 groups; the first group was composed of 8 healthy nonsmoking subjects; the second group included 8 healthy smokers; the third group included 12 nonsmoking patients suffering from chronic obstructive pulmonary emphysema; the fourth group was composed of 7 smokers with chronic obstructive pulmonary emphysema. N,N,N'-trimethyl-N'2-Hydroxy-3-Methyl-5-iodobenzyl-1,3-propanediamine iodine-131(HIPDM) was rapidly injected into the antecubital vein. The influence of 131I-HIPDM by lung clearance was analysed thought imaging of lung and ratio of prolongation of 131I-HIPDM in the lung. Prolongation of 131I-HIPDM in the lung was shown in the smokers with chronic obstructive pulmonary emphysema in 60 minutes, and the healthy smokers, smokers with chronic obstructive pulmonary emphysema in the 24 hours after the injection of 131I-HIPDM. Smoking is an important factor of disturbance of lung clearance.
Adult↗
Demonstration of a functionally active tPA-like plasminogen activator in human platelets.
The mechanism of platelet-enhanced fibrinolysis is unclear. We therefore investigated the fibrinolytic activity of human platelets and demonstrated that they contain a tissue plasminogen activator (tPA)-like plasminogen activator, abbreviated as tPA-like-PA. This activator was detected by ELISA in platelet incubation medium and in platelet Triton extracts. Plasminogen activation assays showed that this tPA-like-PA could induce plasminogen activation to form plasmin. Western blots of Triton extracts incubated with anti-tPA antibody demonstrated a major 64-kD protein band, compared to a 70-kD band for standard single chain tPA, plus a minor 118-kD band corresponding to a complex of tPA-like-PA and plasminogen activator inhibitor (PAI-1). Western blots of Triton extracts incubated with anti-PAI-1 antibody produced an approximately similar high-molecular-weight (118 kD) protein band. Fibrin zymographic analysis of affinity-purified tPA-like-PA demonstrated a major and a minor fibrin lysis zone, which approximately corresponded to the tPA-like-PA and its complex with PAI-1 observed by Western blots. Immunogold labelling and electron microscopy demonstrated that platelet activator, either as the free form or co-localized with PAI-1, was present in granules and in channels of the open canalicular system. We conclude that platelets contain a functionally active tPA-like-PA, whose low fibrinolytic activity might be due to its readily forming a complex with PAI-1. This functionally active tPA-like-PA might contribute to the enhanced fibrinolytic activity of platelets observed in platelet-rich thrombi.
Blood Platelets↗
Cyclical strain increases endothelin-1 secretion and gene expression in human endothelial cells.
We examined the effects of cyclical strain on endothelin-1 (Et-1) secretion and Et-1 mRNA levels in human umbilical vein endothelial cells. Cultured endothelial cells grown on a flexible membrane base were deformed by vacuum to 20% of maximum strain, at 60 cycles/min, for various time periods. The rate of Et-1 release from strain- treated cells and their Et-1 mRNA levels were measured. Cells subjected to strain increased their Et-1 secretion into the culture medium from 0.17 ng/hr/10(6) cells to 0.44 ng/hr/10(6) cells. Concomitantly, the Et-1 mRNA levels in strained cells increased 1.4-, 2.1- or 2.6- fold (vs control unstrained cells) after 0.25, 0.5 or 6 hours of strain, respectively. Cells exposed to longer periods of strain (> 6 hrs) did not further increase their mRNA expression. Pretreatment with calphostin C, a specific inhibitor of protein kinase C, before straining completely abolished Et-1 mRNA expression. These results indicate that mechanical strain can modulate the secretion of Et-1 from endothelial cells by increasing Et-1 mRNA levels via the protein kinase C pathway. Elevation of Et-1 secretion and gene expression in endothelial cells under physiological strain might influence normal or pathological states of the vasculature and cardiac growth.
Cells, Cultured↗
Miniaturized flexible amperometric lactate probe.
A flexible lactate electrode was made of 400 +/- 100 7-micron-diameter carbon fibers, epoxy embedded in a 0.3-mm-diameter polyimide tubing. The electrode was modified by precipitating on it the relatively insoluble complex formed between 1100 kDa partially N-ethylamine quaternized poly[(vinylpyridine)-Os(bipyridine)2Cl]Cl (POs-EA) and lactate oxidase. The steady-state lactate electrooxidation current, at 2 mM lactate concentration and at 22 degrees C, was 400 nA. The 50 +/- 10 microAc cm-2 current density and the 20 mA cm-2 M-1 sensitivity decreased only by 5% when the partial pressure of oxygen was increased from 0.0 to 0.2 atm. The electrode retains its sensitivity after dry storage at 4 degrees C for 4 months in air but loses half of its sensitivity in 7 h at 37 degrees C through polymer desorption when operated at 0.4 V (SCE). To eliminate interference by species that are electrooxidized at 0.4 V (SCE), the lactate-sensing probe was (a) electrically insulated with an epoxy made of poly(vinylimidazole) cross-linked with ethylene glycol diglycidyl ether and (b) coated with an immobilized horseradish peroxidase (HRP)/glucose oxidase (GOX) film. The latter film was formed by coimmobilizing the two enzymes through periodate oxidation of their oligosaccharides to aldehydes and forming Schiff bases between the polyaldehydes and the enzymes' lysyl amines. In the presence of 1 mM glucose and in air, the interfering electrooxidation of 0.1 mM ascorbate was reduced by a factor of 20. This reduction results from formation of hydrogen peroxide in the glucose-catalyzed reaction and H2O2 oxidation of the ascorbate in a reaction catalyzed by HRP.
Biosensing Techniques↗
Regulation of human cardiac myosin heavy chain genes: the effect of catecholamine.
The 5'-flanking regions of the alpha- and beta-cardiac myosin heavy chain (MyHC) genes were excised from the cosmid human genomic clones using Hind III and Xbal for the alpha-MyHC gene, and the Hind III and Hind III sites for the beta-MyHC gene. These fragments were linked to chloramphenicol acetyl transferase (CAT) vector to generate a chimeric fusion gene. These fusion genes were subsequently transfected to neonatal rat cardiac cultured cells to analyze the CAT activity. The alpha-MyHC gene is preferentially expressed as compared to the beta-MyHC. In the presence of norepinephrine (NE) the beta-MyHC gene is remarkably induced (within 24 hours following the addition of norepinephrine to the cardiocyte culture). However, the alpha-MyHC is also induced. Specific alpha andrenergic antagonists such as terazosin (Tz) partially suppressed both the alpha- and beta-MyHC genes as revealed by the CAT activity. These findings suggest that catecholamine does activate the human cardiac MyHC genes but does not differentiate the specific expression of either the alpha- or beta-MyHC genes.
Animals↗
Endothelin stimulates cardiac alpha- and beta- myosin heavy chain gene expression.
The effect of endothelin-1 on cardiac myosin heavy chain gene expression was examined using an isolated neonatal rat myocardial cell culture system. The effects of endothelin-1 on the expression of alpha- and beta- myosin heavy chain genes in the primary rat myocardial cell culture system were examined by S1 nuclease protection analysis. Endothelin-1 was found to stimulate both alpha- and beta- myosin heavy chain gene expression. The 5' flanking regions of both the alpha- and beta- myosin heavy chain gene promoters ligated to a reporter gene, chloramphenicol acetyltransferase, were used to study the effect of endothelin-1 on transcription. Myocardial cells treated with endothelin-1 increased the transcription rate of alpha- and beta- myosin heavy chain genes in a dose-dependent manner. Thus, the hypertrophic effect of endothelin-1 on cardiac myocytes involves augmentation of alpha- and beta- myosin heavy chain gene expression by increasing gene transcription.
Animals↗
Prostaglandin E1 and dibutyryl cyclic AMP enhance platelet resistance to deformation.
The effect of prostaglandin E1 (PGE1) on platelets is mediated through the PGE1 receptor and the consequent maintenance of the platelet's discoid shape. The effects of PGE1 and dibutyryl cAMP (dbcAMP) on the deformability of human platelets were studied. Deformability tests based upon the micropipette aspiration on the platelets were performed by using pipettes with radii (Rp) of 0.26-0.36 microns. The time course of the extension length (Dp, in microns) of the platelets in response to aspiration with a negative pressure (delta P) of 5 cm H2 O (delta P x Rp = 0.15 dynes/cm) was analyzed. PGE1 treatment (0.1 microM) resulted in a decrease of platelet deformability as compared with results obtained for apparently non-activated, control platelets. The deformation index, i.e., Dp/Rp (PGE1-treated)/Dp/Rp (control), was significantly reduced to 0.90 +/- 0.04. DbcAMP treatment also significantly decreased the deformability of platelets and this decrease was dbcAMP dose dependent. In contrast, colchicine- or cytochalasin D-treated platelets increased deformability. PGE1-treated platelets had a higher [cAMP]i than controls. Platelets treated with PGE1 or dbcAMP showed a reduced [Ca2+]i increment induced by thrombin as compared to non-treated controls. These results indicate that PGE1 and dbcAMP treatment of platelets is accompanied by an enhancement of platelet resistance to deformation. The increased [cAMP]i and low [Ca2+]i after PGE1 treatment may limit the rearrangement of cytoskeleton and thus enhance platelet resistance to deformation.
Alprostadil↗
[A preliminary study of immuno-electron microscopy of endothelium in cardiovascular system].
The immunocytochemical localizations of the von Willebrand factor (vWF), endothelin-1 (ET-1) and the beta 2-adrenergic receptor (beta 2R) in cultured human umbilical vein endothelial cells (HUVEC) after thrombin treatment have been demonstrated. Competitive ELISA analysis of these treated cells indicate an increase in vWF deposition on the subendothelial matrix (1.5 folds vs control) and vWF release (3.8 folds vs control) in the culture medium. The vWF-peroxidase, immunogold labeling and in situ hybridization of ET-1 were demonstrated on HUVEC. Double labelling with different sized gold particles for the ET-1 and beta 2R locations were performed on the hearts of young adult WEY, SHR, and SHRsp rats. The results were as follows. (1) Positive vWF deposits were detected on the extracellular matrix, Weibel-Palade bodies and secreting vesicles in the cytoplasm. It is suggested that both the constituted and regulated pathways are involved in the secretion of vWF stimulated by thrombin. (2) The gene expression of ET-1 was detected by light microscopic in situ hybridization in HUVEC. (3) ET-1 was detected by immunoelectron microscopy in the lysosome, cell surface, and extracellular matrix, suggesting that lysosome possibly plays an important role in the processing of ET-1 in HUVEC. (4) The presence of both ET-1 and beta 2R have been successfully detected in adult heart tissues and the endothelial cells of rats. These observations suggest the functional importance of ET-1 and beta 2R.
Animals↗
Electrochemical properties of the diiron core of uteroferrin and its anion complexes.
The reduction potentials (Em) of the purple acid phosphatase from porcine uterus, uteroferrin (Uf), and its phosphate, arsenate, and molybdate complexes were determined by coulometric methods at various pH values. The midpoint potential of Uf at the pH value for optimal enzyme activity (pH 5) was found to be +367 mV versus a normal hydrogen electrode (NHE), while at pH 6.01 Uf exhibits a reduction potential of +306 mV. At pH 6.01 molybdate was found to shift the potential of Uf more positive by 192 mV, while phosphate and arsenate shift the potential of Uf more negative by 193 and 89 mV, respectively. These shifts are consistent with the different susceptibilities of Uf to aerobic oxidation in the presence of these anions. Comparison of the reduction potential of Uf at pH 7.0 with those reported for other dinuclear non-heme iron enzymes and various (mu-oxo)diiron model complexes suggest that the potential of Uf is too positive to be consistent with a mu-oxo-bridge in Ufo. The pH dependence of the reduction potentials of Uf (60 mV/pH unit) and the fact that the electron transfer rate increases with decreasing pH indicate a concomitant participation of a proton during the oxidation-reduction process. This process was assigned to the protonation of a terminally bound hydroxide ligand at the Fe(II) center upon reduction of Ufo. Structural implications provided by the electrochemical data indicate that molybdate affects the dinuclear core in a manner that differs from that of phosphate and arsenate. This observation is consistent with previous spectroscopic and biochemical studies.(ABSTRACT TRUNCATED AT 250 WORDS)
Acid Phosphatase↗
How does the toad's visual system discriminate different worm-like stimuli?
Behavioral experiments show that toads exhibit stimulus- and locus-specific habituation. Different worm-like stimuli that toads can discriminate at a certain visual location form a dishabituation hierarchy. What is the neural mechanism which underlies these behaviors? This paper proposes that the toad discriminates visual objects based on temporal responses, and that discrimination is reflected in different average neuronal firing rates at some higher visual center, hypothetically anterior thalamus. This theory is developed through a large-scale neural simulation which includes retina, tectum and anterior thalamus. The neural model based on this theory predicts that retinal R2 cells play a primary role in the discrimination via tectal small pear cells (SP) and R3 cells refine the feature analysis by inhibition. The simulation demonstrates that the retinal response to the trailing edge of a stimulus is as crucial for pattern discrimination as the response to the leading edge. The new dishabituation hierarchies predicted by this model by reversing contrast and shrinking stimulus size need to be tested experimentally.
Animals↗
Interleukin-1 beta induces interleukin-1 alpha messenger ribonucleic acid expression in primary cultures of Leydig cells.
Previously, we have reported that interleukin-1 (IL-1) can modulate Leydig cell steroidogenesis. Recently, IL-1-like material has been shown to be present in the testis; however, the cellular source of this material remains unclear. In the present study we found that human recombinant IL-1 beta (1-100 ng/ml) caused dose-dependent increases in IL-1 alpha mRNA expression in Leydig cells. Similar to that reported in other tissues, IL-1 alpha mRNA from Leydig cells is mainly 2.2 kilobases. IL-1 alpha mRNA expression in Leydig cells was detectable as early as 2 h after the addition of IL-1 beta (10 ng/ml) and persisted for up to 24 h. Lipopolysaccharide also stimulated IL-1 alpha mRNA expression in these cells, but phorbol ester had no effect. Our results indicate that Leydig cells are a potential source of IL-1, which has both autocrine and paracrine effects.
Actins↗
[Diaphragmatic fatigue in respiratory distress syndrome in dogs].
Diaphragmatic fatigue (DF) in respiratory distress syndrome (RDS) induced by injection of fat were studied in 7 dogs. After injection of fat, all dogs developed respiratory distress and tachypnea, PaO2 fell to the level lower than 8 kPa. Transdiaphragmatic pressure (Pdi) decreased progressively (P less than 0.05-0.001), Pdi-stimulation frequency (Pdi-F) curve shifted to the right, central frequency (Fc), median frequency (Fm) and high/low frequency ratio (H/L) significantly decreased (P less than 0.05-0.001). It is concluded that the contractile force of the diaphragm progressively decreased after RDS was induced, which suggested the occurrence of DF.
Animals↗
[Experimental study of biological glass ceramic and bone morphogenic protein-biological glass ceramic implantation].
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Animals↗
Regulation of insulin-like growth factor-I messenger ribonucleic acid expression in Leydig cells.
In the present study, we evaluated insulin-like growth factor-I (IGF-I) messenger RNA expression in the rat testis. Crude interstitial cells were separated into three distinct bands on 15-60% Percoll density gradients. IGF-I mRNA was mainly localized in the Leydig cell-enriched fraction (band 3), while band 1 and band 2 cells did not contain significant amounts of IGF-I mRNA. Leydig cell IGF-I mRNA consisted of multiple species varying from 0.8 to 7.5 kb and was present in rat Leydig cells all ages examined, from 25 to 55 days old. To further document that IGF-I mRNAs are present in Leydig cells, the method of Klinefelter et al. (Biol. Reprod. (1987) 36, 769-783) was used to isolate highly purified (greater than 98% pure) Leydig cells. Most of the IGF-I mRNA was localized in these Leydig cells, while there was no detectable IGF-I mRNA in the whole testis or other interstitial cells. Furthermore, IGF-I mRNA in Leydig cells was increased more than 2-fold by growth hormone (GH) administration in vivo. This suggests that IGF-I mRNA in Leydig cells is also GH dependent. Interstitial IGF-I produced in Leydig cells may have both autocrine and paracrine effects in the testis.
Animals↗
Human platelet factor V is crosslinked to actin by FXIIIa during platelet activation by thrombin.
Although it has been established that factor V (FV) becomes associated irreversibly with the platelet cytoskeleton after stimulation with thrombin, the chemical nature of this complex is not known. Factor V has recently been demonstrated to be a substrate for factor XIIIa and to form factor V oligomers. We now show that thrombin-activated 125I-FV specifically links to a single protein (43 kDa) of the solubilized platelet membrane in a reaction which requires Ca++ and factor XIIIa. In a purified system, FV, activated by thrombin, forms covalently linked high molecular complexes with 125I-actin catalyzed by factor XIIIa. The site of crosslinking of actin was the factor V fragments, 150 kDa (connecting peptide, C1) and its parent molecule 200 kDa (B). Using radiolabeled actin and unlabeled FV, factor XIIIa catalysed the formation of both homopolymers and heteropolymers. Unlabeled actin was found to compete with radiolabeled FV as a substrate for FXIIIa. To evaluate the biological significance of the crosslinking of factor V to actin, intact platelets were treated with B10 (monoclonal antibody to C1), or monospecific polyclonal antibodies to actin or FXIII. After stimulation with thrombin, the cytoskeleton (material insoluble in Triton X-100) showed markedly decreased 125I-FV in the crosslinked complexes. FV coagulant activity associated with platelet cytoskeleton was also diminished following incubation with an antibody to actin, factor XIII, or B10. These data suggest that FV, through the C1 domain, is crosslinked to actin in the cytoskeleton of thrombin-treated platelets. Activated factor XIII may play a role in plasma FV-platelet interaction as well as the expression of FV derived from the alpha-granules on the cytoskeleton during platelet stimulation.
Actins↗
Interactions between fibrin, collagen and endothelial cells in angiogenesis.
The role of fibrin in the generation of new blood vessels was examined in this study. Using a wound chamber model, we investigated the sequential interactions between endothelial cells and the extracellular matrix during angiogenesis. Silicone tubes 5 mm long and 1.4 mm in internal diameter were sutured to the cut ends of thigh muscles in the rats. The contents of the chamber were removed at intervals for histological, immunohistochemical and electron microscopic studies. We observed an initial phase of fluid accumulation in the wound chamber followed by formation of a fibrin/fibronectin clot. Migration of endothelial cells, macrophages and fibroblasts into the clot occurred after the 1st week. The subsequent phase of fibrinolysis was accompanied by deposition of collagen and organization of endothelial cells into capillary tubes. These findings support the view that angiogenesis is the product of interactions between endothelial cells and a changing extracellular matrix (ECM) and requires the participation of soluble and immobilized plasma proteins and local ECM factors. Our findings indicate that fibrin is intimately involved in both hemostasis and angiogenesis; these are sequential steps in the initial phase of wound healing. Thus, fibrin/fibrinogen occupies a central position and provides a vital link in the initiation of the cascade event of wound healing.
Animals↗