Biomedical subjects

Dong Sun

Publications and source records attributed to Dong Sun.

At least 19 recordsLinked to original sources

PubMed2026

Exploring China's Clean Air Act and associated cardiovascular disease risk: a prospective, quasi-experimental, and causal inference modelling study.

BACKGROUND: Substantial improvements in air quality have been recorded following the implementation of China's Clean Air Act (CCAA) in 2013. However, the association between CCAA implementation and individual-level cardiovascular disease (CVD) risk remains unclear. We aimed to examine the long-term association between CCAA implementation and individual-level predicted CVD risk. METHODS: In this prospective, quasi-experimental study, we used data from the China Kadoorie Biobank, a prospective cohort study that recruited participants from five urban and five rural areas across China between 2004 and 2008, with three resurveys conducted after the baseline survey (in 2008, 2013-14, and 2020-21). We included 34 862 individuals (mean age 51·3 years) who participated in at least one resurvey and had no history of CVD at baseline. Participants were classified into intervention (n=25 497) and control (n=9365) groups based on the local government's targets for particulate matter reduction. We estimated the 10-year risk of incident CVD morbidity or mortality using a validated risk prediction model. We used a difference-in-difference model to assess the long-term association between CCAA implementation and predicted risk, with adjustments made for regional confounders and individual-level characteristics, including demographics, lifestyle factors, medical history, and indoor air pollution exposure. The relationship between changes in long-term exposure to PM2·5, PM10, and O3 and predicted risk after CCAA implementation was analysed using a linear model. The estimated risk differences associated with air pollutant changes were estimated based on the magnitude of changes and their corresponding effect sizes. FINDINGS: After the CCAA was implemented, PM2·5 and PM10 concentrations declined in both groups, but O3 concentrations increased. The intervention group showed a 3·95% (95% CI 3·18-4·72%) lower increase in predicted risk than the control group, with larger estimated differences under stricter enforcement. Between 2013 and 2021, each 10 μg/m3 change in PM2·5 concentration was positively associated with a 1·80 (1·34-2·27) percentage point change in predicted CVD risk, whereas each 10 μg/m3 change in PM10 concentration was associated with a 1·24 (0·84-1·63) percentage point change and each 10 μg/m3 change in O3 concentration with a 0·58 (0·33-0·83) percentage point change. Overall, the observed changes in air pollutants during the study period were associated with an average 6·6 percentage point reduction in predicted CVD risk. INTERPRETATION: The CCAA and improved air quality were associated with a slower increase in predicted CVD risk, supporting the necessity for stricter, multipollutant air quality policies to maximise public health benefits. FUNDING: National Natural Science Foundation of China, Kadoorie Charitable Foundation, Noncommunicable Chronic Diseases-National Science and Technology Major Project, National Key R&D Program of China, Chinese Ministry of Science and Technology, and UK Wellcome Trust.

Journal Article↗

PubMed2007

Anatomical integration of newly generated dentate granule neurons following traumatic brain injury in adult rats and its association to cognitive recovery.

The hippocampus is particularly vulnerable to traumatic brain injury (TBI), the consequences of which are manifested as learning and memory deficits. Following injury, substantive spontaneous cognitive recovery occurs, suggesting that innate repair mechanisms exist in the brain. However, the underlying mechanism contributing to this is largely unknown. The existence of neural stem cells in the adult hippocampal dentate gyrus (DG) and their proliferative response following injury led us to speculate that neurogenesis may contribute to cognitive recovery following TBI. To test this, we first examined the time course of cognitive recovery following lateral fluid percussion injury in rats. Cognitive deficits were tested at 11-15, 26-30 or 56-60 days post-injury using Morris Water Maze. At 11-15 and 26-30 days post-injury, animals displayed significant cognitive deficits, which were no longer apparent at 56-60 days post-TBI, suggesting an innate cognitive recovery at 56-60 days. We next examined the proliferative response, maturational fate and integration of newly generated cells in the DG following injury. Specifically, rats received BrdU at 2-5 days post-injury followed by Fluorogold (FG) injection into the CA3 region at 56 days post-TBI. We found the majority of BrdU+ cells which survived for 10 weeks became dentate granule neurons, as assessed by NeuN and calbindin labeling, approximately 30% being labeled with FG, demonstrating their integration into the hippocampus. Additionally, some BrdU+ cells were synaptophysin-positive, suggesting they received synaptic input. Collectively, our data demonstrate the extensive anatomical integration of new born dentate granule neurons at the time when innate cognitive recovery is observed.

Animals↗

PubMed2006

TNF-alpha upregulates VCAM-1 and NF-kappaB in fibroblasts from nasal polyps.

OBJECTIVE: Lung and synovial fibroblasts produce VCAM-1 in response to TNF-alpha. However, the massive infiltration of eosinophils, the effects of the increased amount of TNF-alpha and the production of VCAM-1 in human nasal polyp fibroblasts are not yet fully understood. The present study examines the role of VCAM-1 and the molecular mechanism of its expression in nasal fibroblasts. METHODS: Nasal fibroblasts were isolated from human nasal polyps and after four passages, the cells were stimulated with TNF-alpha and VCAM-1 expression was examined by ELISA, flow cytometry, and RT-PCR. The activation of NF-kappaB induced by TNF-alpha was determined by electrophoretic mobility shift assays and the influence on the expression of VCAM-1 was investigated. RESULTS: VCAM-1 protein and mRNA were expressed in unstimulated controls and remarkably increased by TNF-alpha stimulation. NF-kappaB activity was enhanced by TNF-alpha stimulation and remarkably suppressed by NF-kappaB proteasome inhibitor. CONCLUSIONS: The present study discovered that nasal fibroblasts produce VCAM-1 protein and mRNA and that production is increased by TNF-alpha stimulation. Furthermore, VCAM-1 expression in nasal fibroblasts is induced through an NF-kappaB-dependent pathway. These findings might provide a rationale for using NF-kappaB inhibitors as a treatment for nasal inflammatory diseases such as polyps.

Cells, Cultured↗

PubMed2006

Electrochemical determination of 2-chlorophenol using an acetylene black film modified glassy carbon electrode.

Herein, an insoluble acetylene black (AB) was dispersed into water in the presence of a special kind of surfactant: dihexadecyl hydrogen phosphate (DHP), resulting in a homogeneous and stable AB-DHP suspension. Thus, a novel AB-DHP composite film coated glassy carbon electrode (GCE) was fabricated via coating technology. Additionally, the electrochemical behaviors of 2-chlorophenol at bare GCE, DHP-modifed GCE, and AB-DHP modified GCE were investigated, respectively. Compared with the unmodified and DHP-coated GCE, the AB-DHP film-modified GCE significantly enhances the oxidation peak current of 2-chlorophenol, and thus greatly improves its determining sensitivity, suggesting that this new modified electrode has great potential in the determination of trace level of 2-chlorophenol. All the experimental conditions, which affect the electrochemical response of 2-chlorophenol, were studied. Finally, a sensitive and simple voltammetric method with a good linear relationship in the range 2.0 x 10(-7)-4.0 x 10(-5) mol/L, was developed. The detection limit of 2-chlorophenol was 5.0 x 10(-8) mol/L for 2 min accumulation (S/N = 3). This electrode was successfully applied to detect 2-chlorophenol in water samples.

Acetylene↗

PubMed2006

Role of peritubular capillary loss and hypoxia in progressive tubulointerstitial fibrosis in a rat model of aristolochic acid nephropathy.

BACKGROUND/AIMS: To investigate the effects of peritubular capillary (PTC) loss and hypoxia on the progression of tubulointerstitial fibrosis in a rat model of aristolochic acid nephropathy (AAN). METHODS: Female Wistar rats received Caulis aristolochiae manshuriensis (CAM) decoction by gavage for 8 weeks, and were sacrificed at 8, 12 and 16 weeks, respectively, after administration. Blood urea nitrogen (BUN), serum creatinine (Scr) and urinary protein were monitored prior to sacrifice. PTC loss and tubulointerstitial hypoxia were assessed by CD34 immunostaining and hypoxia-inducible factor-alpha subunit 1 (HIF-1alpha) expression, respectively. Myofibroblasts were assessed by alpha-smooth muscle actin (alpha-SMA) expression. The expression of angiogenic factor was assessed by vascular endothelial growth factor (VEGF). RESULTS: AAN rats differed from controls by increased BUN, Scr and 24-hour urinary protein excretion rates. There was a progressive loss of PTCs in the AAN model, which was associated with the decreased expression of VEGF. A significant increase in nuclear localization of HIF-1alpha was seen 16 weeks after treatment with CAM decoction in the context of severe tubulointerstitial damage. Multifocal tubulointerstitial fibrosis was seen in AAN rats at weeks 12 and 16, predominantly in the area of the outer stripe and outer medulla. No significant pathologic changes were found in control rats. CONCLUSION: Following the reduction of PTCs density and up-regulation of HIF-1alpha, the tubulointerstitial fibrosis area increased. Ischemia and hypoxia are the important causes of severe tubulointerstitial fibrosis in AAN rats.

Animals↗

PubMed2006

Hexagonal nanoporous germanium through surfactant-driven self-assembly of Zintl clusters.

Surfactant templating is a method that has successfully been used to produce nanoporous inorganic structures from a wide range of oxide-based material. Co-assembly of inorganic precursor molecules with amphiphilic organic molecules is followed first by inorganic condensation to produce rigid amorphous frameworks and then, by template removal, to produce mesoporous solids. A range of periodic surfactant/semiconductor and surfactant/metal composites have also been produced by similar methods, but for virtually all the non-oxide semiconducting phases, the surfactant unfortunately cannot be removed to generate porous materials. Here we show that it is possible to use surfactant-driven self-organization of soluble Zintl clusters to produce periodic, nanoporous versions of classic semiconductors such as amorphous Ge or Ge/Si alloys. Specifically, we use derivatives of the anionic Ge9(4-) cluster, a compound whose use in the synthesis of nanoscale materials is established. Moreover, because of the small size, high surface area, and flexible chemistry of these materials, we can tune optical properties in these nanoporous semiconductors through quantum confinement, by adsorption of surface species, or by altering the elemental composition of the inorganic framework. Because the semiconductor surface is exposed and accessible in these materials, they have the potential to interact with a range of species in ways that could eventually lead to new types of sensors or other novel nanostructured devices.

Journal Article↗

PubMed2006

[Influence of hypoxia caused by impairment of peritubular capillary on the progression of chronic aristolochic acid nephropathy].

OBJECTIVE: To investigate the manifestation of impairment of peritubular capillary (PTC) in chronic aristolochic acid nephropathy (CAAN) and the influence of hypoxia caused by PTC impairment on the progression of CAAN. METHODS: Fifty-four Wistar rats were randomly divided into 2 groups: Group A (n = 30, perfused intragastrically with decoction of Caulis aristolochia manchuriensis for 8 weeks) and Group B (n = 24, perfused intragastrically with drinking water for 8 weeks). At weeks 8, 12, and 16 ten rats in Group A and 8 rats in Group B were killed. Specimens of blood and urine were collected before the killing of the rats to detect the blood urea nitrogen (BUN), serum creatinine (Scr), and urine protein. HE and Masson staining and microscopy were used to observe the pathology of the kidney. Immunohistochemistry and Western blotting were used to detect the expression of hypoxia-inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), and CD34. Correlation analysis was conducted to study the relationships among these indices. RESULTS: Since week 8 BUN, Scr, and urine protein of Group A began to increase in comparison with Group B (all P < 0.05). Pathological changes of the kidney began to appear in Group A since week 8 with the decrease of PTC density. HIF-1alpha was not expressed in Group B, and in Group A HIF-1alpha expression began to increase since week 8 and became significantly higher than that of Group B since week 12. At week 16, the PTC density and VEGF-IOD of Group A were 8.10 +/- 2.28/0.13 mm(2) and (2.78 +/- 0.78) x 10(3) respectively, both significantly lower than those of Group B [(42.80 +/- 4.49)/0.13 mm(2) and (26.49 +/- 9.34) x 10(3) respectively, both P < 0.01], and the HIF-1alpha-IOD of Group A was (7.11 +/- 1.20) x 10(3), significantly higher than that of Group B [(0.44 +/- 0.10) x 10(3), P < 0.01]. CD34 was highly expressed in Group B, and the CD34 expression of Group A began to decrease since week 16. HIF-1alpha expression was positively correlated with Scr (r = -0.945, P < 0/01), and PTC density and VEGF expression were negatively correlated with Scr (r = -0.907, P < 0.01 and r = -0.690, P < 0.01). PTC density was negatively correlated with HIF-1alpha expression (r = -0.880, P < 0.01). CONCLUSION: Severe hypoxia exists following PTC injury in CAAN. Hypoxia is correlated with the progression of CAAN.

Animals↗

PubMed2006

COX-2 contributes to the maintenance of flow-induced dilation in arterioles of eNOS-knockout mice.

Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in the gene for endothelial nitric oxide synthase (eNOS), flow-induced dilation (FID) is mediated by endothelial PGs. Thus the present study aimed to identify the specific isoform of cyclooxygenase (COX) responsible for the compensatory mediation of FID in arterioles of eNOS-knockout (KO) mice. Experiments were conducted on gracilis muscle arterioles of male eNOS-KO and wild-type (WT) mice. Basal tone and magnitude of FID of arterioles were comparable in the two strains of mice. A role for COX isoforms in the mediation of the responses was assessed by use of valeryl salicylate (3 mM) and NS-398 (10 microM), inhibitors of COX-1 and COX-2, respectively. In eNOS-KO arterioles, valeryl salicylate or NS-398 alone inhibited FID (at maximal flow rate) by approximately 51% and approximately 58%, respectively. Administration of both inhibitors eliminated the dilation. In WT arterioles, inhibition of COX-2 did not significantly affect FID, whereas inhibition of COX-1 decreased the dilation by approximately 57%. The residual portion of the response was abolished by additional administration of Nomega-nitro-L-arginine methyl ester. Western blot analysis indicated a comparable content of COX-1 protein in arterioles of WT and eNOS-KO mice. COX-2 protein, which was not detectable in arterioles of WT mice, was strongly expressed in arterioles of eNOS-KO mice, together with an upregulation of COX-2 gene expression. Immunohistochemical staining confirmed the presence of COX-2 in the endothelium of eNOS-KO arterioles. In conclusion, COX-2-derived PGs are the mediators responsible for maintenance of FID in arterioles of eNOS-deficient mice.

Animals↗

PubMed2006

Characterizing the mitogenic effect of basic fibroblast growth factor in the adult rat striatum.

The limited regenerative capacity of the adult central nervous system (CNS) renders it unable to fully recover from injury or disease. Although stem and progenitor cells have been shown to reside throughout the brain, in most regions they exist as quiescent cell populations and do not divide sufficiently to replace damaged or destroyed cells. In an effort to stimulate the proliferative capacity of these multipotent cells, we sought to determine the in vivo response of the adult CNS to an exogenous application of basic fibroblast growth factor (bFGF), a known mitogen to stem and progenitor cells. Specifically, we administered bFGF to the striatum of adult rats at varying concentrations (1, 10, 100, 1,000, or 10,000 ng/mL in saline) so as to establish a dose response curve for bFGF-induced cell proliferation. Forty-eight hours following bFGF administration, animals were injected with 5-bromodeoxyuridine to label dividing cells. Of the doses assessed, we found that 1,000 ng/mL bFGF generated the greatest proliferative response over that observed in animals given a control saline injection. Further, the proliferative response of the striatum to bFGF administration could be enhanced twofold by supplementing this growth factor with heparin sulfate, a factor that facilitates the binding of bFGF to its receptors. By determining the maturational fate of the proliferating cell population, we found that a significant proportion of newly generated cells resulting from bFGF administration differentiated into astrocytes. Collectively, these studies demonstrate the potential of bFGF to promote proliferation in the adult brain, which can be exploited to facilitate cell replacement therapies.

Animals↗

PubMed2005

Contribution of 20-HETE to augmented myogenic constriction in coronary arteries of endothelial NO synthase knockout mice.

Previous studies suggested an important role for 20-HETE in the regulation of myogenic responses. Thus, pressure-diameter relationships were investigated in isolated, cannulated coronary arteries (approximately 100 microm) from male endothelial NO synthase knockout (eNOS-KO) and wild-type (WT) mice. All arteries constricted in response to step increases in perfusate pressure from 20 to 100 mm Hg. This constriction was significantly enhanced from 40 to 100 mm Hg in arteries of eNOS-KO compared with those of WT mice. For example, at 60 and 100 mm Hg, respectively, the normalized diameter (expressed as a percentage of the corresponding passive diameter) of arteries of eNOS-KO mice was 10% and 12% smaller than that of WT mice. Removal of the endothelium did not significantly affect the responses of vessels from either strain of mice. However, N-methylsulfonyl-12,12-dibromododec-11-enamide (5x10(-6) M), an inhibitor of cytochrome P-450 (CYP)/omega-hydroxylase, significantly attenuated the greater myogenic constriction of arteries from eNOS-KO mice by approximately 12% at each pressure step but did not significantly affect responses of those from WT mice, leading to a comparable myogenic response in the 2 strains. Western blot analysis demonstrated a comparable CYP4A protein content in coronary arteries of the 2 strains of mice. However, production of 20-HETE, measured by fluorescent high-performance liquid chromatography assay was approximately 2.7-fold greater in eNOS-KO compared to WT mice. Thus, as a function of eNOS deficiency, the enhanced coronary artery constriction to pressure is attributable to an increased activity of omega-hydroxylase, which, consequently, increases the synthesis of 20-HETE in vascular smooth muscle.

Amides↗

PubMed2005

TNF-alpha and endotoxin increase hypoxia-induced VEGF production by cultured human nasal fibroblasts in synergistic fashion.

OBJECTIVE: Vascular endothelial growth factor (VEGF) promotes angiogenesis and is associated with the invasion and metastasis of malignant tumors. It enhances vascular permeability and is expressed in inflammatory nasal as well as middle-ear mucosa. As the mechanism of VEGF induction during chronic inflammation, such as chronic paranasal sinusitis (CPS) remains to be clarified, we studied the factors regulating the production of VEGF in cultured human nasal fibroblasts and discussed the role of VEGF in the pathogenesis of CPS. METHODS: We used ELISA to quantify VEGF levels in paranasal sinus effusions, nasal secretions, and serum from patients with CPS. In addition, we cultured human nasal fibroblasts isolated from nasal polyps of CPS patients and studied the effects of hypoxia, TNF-alpha, and endotoxin on their production of VEGF using ELISA and PCR. RESULTS: The VEGF concentration was significantly higher in paranasal sinus effusions than in nasal secretions and serum. Nasal fibroblasts produced high levels of VEGF, when cultured under hypoxic condition and this production was remarkably enhanced in the presence of TNF-alpha or endotoxin. CONCLUSION: VEGF is locally produced in paranasal sinuses as well as nasal mucosa and its production is increased in patients with CPS. Hypoxia is associated with the production of VEGF by nasal fibroblasts and TNF-alpha and endotoxin may act synergistically to enhance VEGF production in paranasal sinuses under hypoxic condition.

Analysis of Variance↗

PubMed2005

Increased superoxide leads to decreased flow-induced dilation in resistance arteries of Mn-SOD-deficient mice.

The role of mitochondrial manganese-superoxide dismutase (Mn-SOD) in the maintenance of vascular function has not yet been studied. Thus we examined flow- and agonist-induced dilations in isolated mesenteric arteries (approximately 90 microm in diameter) of Mn-SOD heterozygous (Mn-SOD+/-) and wild-type (WT) mice. Increases in flow elicited dilations in all vessels, but the magnitude of the dilation was significantly less in vessels of Mn-SOD+/- mice than in those of WT mice (64 vs. 74% of passive diameter). N(omega)-nitro-L-arginine methyl ester inhibited the dilation in vessels of WT mice but had no effect on vessels of Mn-SOD+/- mice. Tempol or tiron (superoxide scavengers) increased flow-induced dilation in vessels of Mn-SOD+/- mice. Acetylcholine- and sodium nitroprusside-induced, but not adenosine-induced, dilations were also decreased in arteries of Mn-SOD+/- mice. Superoxide levels in the arteries of Mn-SOD+/- mice were significantly increased. Western blot analysis confirmed a 50% reduction of Mn-SOD protein in the vessels of Mn-SOD+/- mice. A 41% reduction in endothelial nitric oxide synthase (eNOS) protein and a 37% reduction in eNOS activity were also found in the vessels of Mn-SOD+/- mice. Whereas there was no difference in eNOS protein in kidney homogenates of WT and Mn-SOD+/- mice, a significant reduction of nitric oxide synthase activity was found in Mn-SOD+/- mice, which could be restored by the administration of tiron. We conclude that an increased concentration of superoxide due to reduced activity of Mn-SOD, which inactivates nitric oxide and inhibits eNOS activity, contributes to the impaired vasodilator function of isolated mesenteric arteries of Mn-SOD+/- mice. These results suggest that Mn-SOD contributes significantly to the regulation of vascular function.

Animals↗

PubMed2005

Epoxyeicosatrienoic acids are released to mediate shear stress-dependent hyperpolarization of arteriolar smooth muscle.

We hypothesized that shear stress stimulates the release of epoxyeicosatrienoic acids (EETs) from arteriolar endothelium, which directly hyperpolarize smooth muscle. To test this hypothesis, a perfusion system, consisting of two separate, serially connected chambers (A and B), was used. A donor vessel, isolated from gracilis muscle of female NO-deficient mice and rats, was cannulated in chamber A. In chamber B, an endothelium-denuded detector vessel isolated from mesentery of these animals was cannulated. In the presence of indomethacin, 5, 10, and 20 dyne/cm2 shear stress elicited dilation of donor vessels, followed by dilation of detector vessels. Changes in membrane potential of the detector vessel smooth muscle cells in response to the perfusate from 5 and 10 dyne/cm2 shear stress-stimulated donor vessels was also recorded (by approximately -12 to -15 and -20 to -30 mV, respectively). Exposing detector vessels to 30 mmol/L KCl or pretreating them with iberiotoxin abolished their hyperpolarization and dilation to the flow of perfusate. Pretreatment of donor vessels with PPOH, an inhibitor of cytochrome P-450/epoxygenase, eliminated dilator responses in both donor and detector vessels, as well as the hyperpolarization of detector vessels. GC-MS analysis showed increasing release of EETs into the perfusate collected from 1, 5, and 10 dyne/cm2 shear stress-stimulated arterioles, which was abolished by PPOH. Thus, EETs, released from endothelial cells of donor vessels stimulated with shear stress, hyperpolarize smooth muscle of downstream detector vessels, confirming their identity as endothelium-derived hyperpolarizing factors and suggesting that gap junctional communication may not be necessary for shear stress-stimulated EDHF-mediated vasodilation.

8,11,14-Eicosatrienoic Acid↗

PubMed2005

Heterotypic neuronal differentiation of adult subependymal zone neuronal progenitor cells transplanted to the adult hippocampus.

Neuronal progenitor cells (NPCs) residing in the adult subependymal zone (SEZ) are a potential source of expandable cells for autologous transplantation to replace neurons lost in multiple types of brain injury. To characterize the capacity of these cells for neuronal differentiation in a mature ectopic environment, NPCs expanded from the SEZ of adult rats were transplanted to the adult dentate gyrus. Cultures comprised a heterogeneous population of proliferating cells, which expressed nestin (47%) and GFAP (37%), with many cells expressing both progenitor cell markers (31%). In grafts of undifferentiated cells, as well as in grafts of cells that were induced to differentiate in vitro with retinoic acid, 35% of the transplanted SEZ-derived cells exhibited immunohistochemical and morphological features characteristic of hippocampal granule cell neurons. These novel results indicate that in vitro expanded adult SEZ NPCs are capable of heterotypic neuronal differentiation in a neurogenic region of the adult brain.

Animals↗

PubMed2005

Cell proliferation and neuronal differentiation in the dentate gyrus in juvenile and adult rats following traumatic brain injury.

It is well known that the cognitive functions of juveniles recover to a greater extent than adult patients following traumatic brain injury (TBI). The exact mechanisms underlying this age-related disparity are unknown; however, we speculate that this improved recovery in juveniles following TBI may be associated with an endogenous neurogenic response in the hippocampus. We, therefore, examined the effects of TBI on cellular proliferation and differentiation in the dentate gyrus (DG) of the hippocampus in juvenile and adult rats following lateral fluid percussion injury (FPI). The temporal profile of the injury-induced proliferative response was determined using BrdU labeling at varying survival times. The differentiation of these newly generated cells was investigated using cell-type specific markers. We found that, following injury, there was a significant increase in cell proliferation in the DG in both injured juveniles and adults at 2 days post injury when compared to shams. When comparing the extent of cell proliferation between juveniles and adults following TBI, the absolute number of cells generated in the subgranular zone (SGZ) was far greater in the juveniles. Moreover, the percentage of newly generated cells in the SGZ that differentiated into neurons was nearly two times higher in the juveniles as compared to adults. Conversely, more glial differentiation was observed in the DG of adult rats. These findings provide compelling evidence that age-related differences in the neurogenic response to injury may underlie the differences observed in cognitive recovery in juvenile mammals as compared to adults following TBI.

Age Factors↗

PubMed2005

Inhibition of vascular endothelial growth factor by macrolides in cultured fibroblasts from nasal polyps.

OBJECTIVE: In order to study a new mechanism of efficacy of 14-membered ring macrolides in treating chronic rhinosinusitis, inhibitory effects of macrolides on vascular endothelial growth factor production were examined in vitro. METHODS: Vascular endothelisal growth factor production in cultured fibloblasts from human nasal polyps obtained from surgery for chronic paranasal sinusitis stimulated by hypoxia or tumor necrosis factor-alpha was assessed under the administration of Clarithromycin or Roxisthromycin by enzyme linked immunosorbent assay and reverse transcriptase polymerase chain-reaction. RESULTS: Dose-dependent inhibitory effects on vascular endothelisal growth factor production stimulated by hypoxia or tumor necrosis factor-alpha were noted in the groups treated with Clarithromycin and Roxisthromycin, including inhibition of vascular endothelisal growth factor mRNA levels. CONCLUSION: While, to date, several evidences have indicated that the mechanisms by which 14-membered ring macrolides reduce inflammation are not simply bactericidal, these results suggest another new mechanism of efficacy of macrolides in treating chronic rhinosinusitis.

Adult↗

PubMed2005

Wigner distribution function of Hermite-cosine-Gaussian beams through an apertured optical system.

By introducing the hard-aperture function into a finite sum of complex Gaussian functions, the approximate analytical expressions of the Wigner distribution function for Hermite-cosine-Gaussian beams passing through an apertured paraxial ABCD optical system are obtained. The analytical results are compared with the numerically integrated ones, and the absolute errors are also given. It is shown that the analytical results are proper and that the calculation speed for them is much faster than for the numerical results.

Journal Article↗

PubMed2005

Effect of perfluorocarbons on brain oxygenation and ischemic damage in an acute subdural hematoma model in rats.

OBJECT: This study was conducted to determine whether perfluorocarbons (PFCs) improve brain oxygenation and reduce ischemic brain damage in an acute subdural hematoma (SDH) model in rats. METHODS: Forty adult male Sprague-Dawley rats were allocated to four groups: (1) controls, acute SDH treated with saline and 30% O2; (2) 30-PFC group, acute SDH treated with PFC infusion in 30% O2; (3) 100-O2 group, acute SDH treated with 100% O2; and (4) 100-PFC group, acute SDH treated with PFC plus 100% O2. Ten minutes after the induction of acute SDH, a single dose of PFC was infused and 30% or 100% O2 was administered simultaneously. Four hours later, half of the rats were killed by perfusion for histological study to assess the extent of ischemic brain damage. The other half were used to measure brain tissue oxygen tension (PO2). The volume of ischemic brain damage was 162.4 +/- 7.6 mm3 in controls, 165.3 +/- 11.3 mm3 in the 30-PFC group, 153.4 +/- 17.3 mm3 in the 100-O2 group, and 95.9 +/- 12.8 mm3 in the 100-PFC group (41% reduction compared with controls, p = 0.002). Baseline brain tissue PO2 values were approximately 20 mm Hg, and after induction of acute SDH, PO2 rapidly decreased and remained at 1 to 2 mm Hg. Treatment with either PFC or 100% O2 improved brain tissue PO2, with final values of 5.14 and 7.02 mm Hg, respectively. Infusion of PFC with 100% O2 improved brain tissue PO2 the most, with a final value of 15.16 mm Hg. CONCLUSIONS: Data from the current study demonstrated that PFC infusion along with 100% O2 can significantly improve brain oxygenation and reduce ischemic brain damage in acute SDH.

Acute Disease↗