Biomedical subjects
Publications and source records attributed to R Wang.
The procedures outlined in this article by Rui Wang, Fotis Kafatos and Liangbiao Zheng are well suited to studies of field mosquito populations, and also to the genetic mapping of qualitative and quantitative traits of Anopheles gambiae, a major malaria vector in Africa. An accurate, reproducible and high-throughput microsatellite genotyping procedure has been established.
The amyloid precursor protein undergoes proteolysis at several sites to yield a number of functionally relevant peptides, including beta-amyloid and the soluble amyloid precursor protein derivatives alpha-soluble amyloid precursor protein and beta-soluble amyloid precursor protein. beta-Amyloid is the primary constituent of senile plaques associated with Alzheimer's disease, while a-soluble amyloid precursor protein promotes synaptogenesis and plays a role in neuroprotective processes. We tested for age-related alterations in these amyloid precursor protein proteolytically derived peptides by measuring the levels of alpha-soluble amyloid precursor protein, total soluble amyloid precursor proteins (alpha- and beta-soluble amyloid precursor protein combined) and beta-amyloid in cerebrospinal fluid from three-, 13- and 23-month-old Fischer-344 rats. Western blot analysis using selective antibodies revealed 50% less total soluble amyloid precursor protein and a-soluble amyloid precursor protein in cisternal cerebrospinal fluid from 23-month-old rats compared with three- and 13-month-old animals. Mass spectrometric analysis indicated, however, that beta-amyloid in cerebrospinal fluid was not different between the three age groups. In a second group of young (five to six months of age) and aged (24-25 months of age) rats, spatial working and reference memory were assessed in a water maze followed by collection of cerebrospinal fluid. As a group, the aged rats consistently performed below the young rats in both working and reference memory tests. The aged rats also had 49% less cerebrospinal fluid alpha-soluble amyloid precursor protein than did their younger counterparts. There was a positive correlation (r= 0.52-0.57, P < 0.001) between performance in spatial memory tasks and cerebrospinal fluid alpha-soluble amyloid precursor protein in these young and aged rats. These results suggest that there is a positive association between cerebrospinal fluid levels of alpha-soluble amyloid precursor protein and cognitive performance in rats, and that alpha-soluble amyloid precursor protein may be involved in the spatial learning and memory changes that accompany ageing.
In this report, the quantitative structure-activity relationship (QSAR) analyses of substituted phenols, vitamin E derivatives and flavonoids are presented. Two models have been derived using calculated parameters such as the heat of formation (Hf), the energy of the lowest unoccupied molecular orbital of radicals (E(lumo-r)) the energy of the highest occupied molecular orbital of the parent compounds (E(homo)) and the number of hydroxyl groups (OH). These models can be used to estimate the redox potentials or antioxidant activities of new substituted phenolic compounds or vitamin E derivatives. The Trolox equivalent antioxidant capacities (TEACs) of 42 different flavonoids are found to be mainly governed by the number and location of hydroxyl groups on the flavonoid ring system.
Infection of macrophage lineage cells is a feature of primate lentivirus replication, and several properties of primate lentiviruses seem to have evolved to promote the infection of macrophages. Here we demonstrate that the accessory gene product Nef induces the production of two CC-chemokines, macrophage inflammatory proteins 1alpha and 1beta, by HIV-1-infected macrophages. Adenovirus-mediated expression of Nef in primary macrophages was sufficient for chemokine induction. Supernatants from Nef-expressing macrophages induced both the chemotaxis and activation of resting T lymphocytes, permitting productive HIV-1 infection. These results indicate a role for Nef in lymphocyte recruitment and activation at sites of virus replication.
The genetic lesion underlying familial British dementia (FBD), an autosomal dominant neurodegenerative disorder, is a T-A transversion at the termination codon of the BRI gene. The mutant gene encodes BRI-L, the precursor of ABri peptides that accumulate in amyloid deposits in FBD brain. We now report that both BRI-L and its wild-type counterpart, BRI, were constitutively processed by the proprotein convertase, furin, resulting in the secretion of carboxyl-terminal peptides that encompass all or part of ABri. Elevated levels of peptides were generated from the mutant BRI precursor. Electron microscopic studies revealed that synthetic ABri peptides assembled into irregular, short fibrils. Collectively, our results support the view that enhanced furin-mediated processing of mutant BRI generates fibrillogenic peptides that initiate the pathogenesis of FBD.
Pendred syndrome is the most common form of syndromic deafness and characterized by congenital sensorineural hearing loss and goitre. This disorder was mapped to chromosome 7 and the gene causing Pendred syndrome (PDS) was subsequently identified by positional cloning. PDS encodes a putative transmembrane protein designated pendrin. Pendrin is closely related to a family of sulfate transport proteins that includes the rat sulfate-anion transporter (encoded by Sat-1; 29% amino acid sequence identity), the human diastrophic dysplasia sulfate transporter (encoded by DTD; 32%) and the human sulfate transporter 'downregulated in adenoma' (encoded by DRA; 45%). On the basis of this homology and the presence of a slightly modified sulfate-transporter signature sequence comprising its putative second transmembrane domain, pendrin has been proposed to function as a sulfate transporter. We were unable to detect evidence of sulfate transport following the expression of pendrin in Xenopus laevis oocytes by microinjection of PDS cRNA or in Sf9 cells following infection with PDS-recombinant baculovirus. The rates of transport for iodide and chloride were significantly increased following the expression of pendrin in both cell systems. Our results demonstrate that pendrin functions as a transporter of chloride and iodide, but not sulfate, and may provide insight into thyroid physiology and the pathophysiology of Pendred syndrome.
1. This study was carried out to investigate novel cardioprotective effects of urea and the underlying mechanisms. The cardiac functions under oxidative stress were evaluated using Langendorff perfused isolated heart. 2. Isolated dogfish shark hearts tolerated the oxidative stress generated by electrolysis (10 mA, 1 min) of the perfusion solution (n=4), and also showed normal cardiac functions during post-ischaemia reperfusion (n=4). The high concentration of urea (350 mM) in the heart perfusate was indispensable for maintaining the normal cardiac functions of the shark heart. 3. Urea at 3 - 300 mM (n=4 for each group) protected the isolated rat heart against both electrolysis-induced heart damage and post-ischaemia reperfusion-induced cardiac injury. 4. A concentration-dependent scavenging effect of urea (3 - 300 mM, n=4 for each group) against electrolysis-induced reactive oxygen species was also demonstrated in vitro. 5. Urea derivatives as hydroxyurea, dimethylurea, and thiourea had antioxidant cardioprotective effect against the electrolysis-induced cardiac dysfunction of rat heart, but were not as effective as urea in suppressing the post-ischaemia reperfusion injury. 6. Our results suggest that urea and its derivatives are potential antioxidant cardioprotective agents against oxidative stress-induced myocardium damage including the post-ischaemia reperfusion-induced injury.
Salsalate and its metabolite salicylate are inhibitors of thyroid hormone binding to serum transport proteins and reduce serum total thyroxine (T4) and triiodothyronine (T3) in vivo. The present study is the first to examine and compare salsalate and salicylate binding to human thyroxine-binding globulin (TBG), transthyretin (TTR), albumin (ALB), and whole human serum, and displacement by salsalate and salicylate of T4 from isolated TBG, TTR, ALB. Salsalate and salicylate binding were studied by ultrafiltration at salsalate concentrations of 0.24-1.16 mM (62-300 microg/mL) and salicylate concentrations of 0.0375-2.25 mM (6.0-360 microg/mL). T4 displacement by salsalate and salicylate from TBG, TTR, and ALB was studied by equilibrium dialysis at salsalate concentrations of 0 to 1.52 mM (0-393 microg/mL) and salicylate concentrations of 0 to 60 mM (0-9600 microg/mL). In normal human serum, 95% of salsalate and 76% of salicylate were protein-bound. In the presence of isolated ALB, 89% of salsalate and 64% of salicylate were ALB-bound. Both salsalate and salicylate inhibited T4 binding to all 3 major T4 binding proteins. Both displaced proportionately more T4 from TBG compared with TTR and ALB. The principal site to which both salsalate and salicylate in serum is bound (ALB) is different from the principal site from which they displace T4 (TBG). Salsalate potency in displacing T4 from TBG and ALB was approximately 100-fold greater than salicylate potency.
Loops are structurally variable regions, but the secondary structural elements bracing loops are often conserved. Motifs with similar secondary structures exist in the same and different protein families. In this study, we made an all-PDB-based analysis and produced 495 motif families accessible from the Internet. Every motif family contains some variable loops spanning a common framework (a pair of secondary structures). The diversity of loops and the convergence of frameworks were examined. In addition, we also identified 119 loops with conformational changes in different PDB files. These materials can give some directions for functional loop design and flexible docking.
The purpose of this study was to examine the effect of incubation temperature on the structural integrity of the islet during culture. Islets were isolated from the pancreas of the Syrian golden hamster and cultured in a collagen gel for < or =12 days at 24 degrees C or 37 degrees C. At 24 degrees C, cells in the islet periphery died, leading to a complete disintegration of the mantle region in 37.4+/-5.6% of the islets. In comparison, at 37 degrees C, few islets exhibited mantle disintegration (p<0.001). Insulin immunoreactivity was distributed nonhomogeneously in islets at 24 degrees C, and the intensity of the staining, by using a semiquantitative scale (0-3), was +1. Islets cultured at 37 degrees C had a normal homogeneous distribution of insulin immunoreactivity with a score of +3. As the pancreas is a complex gland composed of different cell types, and cell-cell interactions are known to be important in the maintenance of cell survival, additional experiments were repeated to include the coculture of islets with duct epithelial cells. The proportion of islets that developed mantle disintegration was now reduced to 2.5+/-0.3% (p<0.001), comparable to that seen at 37 degrees C. Similar results were obtained for islets cultured in the presence of duct-conditioned medium (DCM). Together with the preservation of the islet mantle, islets cultured in the presence of duct epithelial cells or DCM had a normal homogeneous distribution of insulin immunoreactivity, with a staining intensity of +3. We conclude that incubation temperature has a profound effect on the structural integrity of islets, and that the detrimental effects of low-temperature culture can be mitigated by coculture of islets with secretory products derived from pancreatic ductal cells. These data provide evidence for a trophic relation between pancreatic islets and ductal epithelium.
Most work on protective immunity against the pre-erythrocytic stages of malaria has focused on induction of antibodies that prevent sporozoite invasion of hepatocytes, and CD8(+) T-cell responses that eliminate infected hepatocytes. We recently reported that immunization of A/J mice with an 18-amino-acid synthetic linear peptide from Plasmodium yoelii sporozoite surface protein 2 (SSP2) in TiterMax adjuvant induces sterile protection that is dependent on CD4(+) T cells and gamma interferon (IFN-gamma). We now report that immunization of inbred A/J mice and outbred CD1 mice with each of two linear synthetic peptides from the 17-kDa P. yoelii hepatocyte erythrocyte protein (HEP17) in the same adjuvant also induces protection against sporozoite challenge that is dependent on CD4(+) T cells and IFN-gamma. The SSP2 peptide and the two HEP17 peptides are recognized by B cells as well as T cells, and the protection induced by these peptides appears to be directed against the infected hepatocytes. In contrast to the peptide-induced protection, immunization of eight different strains of mice with radiation-attenuated sporozoites induces protection that is absolutely dependent on CD8(+) T cells. Data represented here demonstrate that CD4(+) T-cell-dependent protection can be induced by immunization with linear synthetic peptides. These studies therefore provide the foundation for an approach to pre-erythrocytic-stage malaria vaccine development, based on the induction of protective CD4(+) T-cell responses, which will complement efforts to induce protective antibody and CD8(+) T-cell responses.
Molecular basis of native voltage-dependent K(+) (Kv) channels in smooth muscle cells (SMCs) from rat mesenteric arteries was investigated. The whole cell patch-clamp study revealed that a 4-aminopyridine-sensitive delayed rectifier K(+) current (I(K)) was the predominant K(+) conductance in these cells. A systematic screening of the expression of 18 Kv channel genes using RT-PCR technique showed that six I(K)-encoding genes (Kv1.2, Kv1.3, Kv1.5, Kv2.1, Kv2.2, and Kv3.2) were expressed in mesenteric artery. Although no transient outward Kv currents (I(A)) were recorded in the studied SMCs, transcripts of multiple I(A)-encoding genes, including Kv1.4, Kv3.3, Kv3.4, Kv4.1, Kv4.2, and Kv4.3 as well as I(A)-facilitating Kv beta-subunits (Kvbeta1, Kvbeta2, and Kvbeta3), were detected in mesenteric arteries. Western blot analysis demonstrated that four I(K)-related Kv channel proteins (Kv1.2, Kv1. 3, Kv1.5, and Kv2.1) were detected in mesenteric artery tissues. The presence of Kv1.2, Kv1.3, Kv1.5, and Kv2.1 channel proteins in isolated SMCs was further confirmed by immunocytochemistry study. Our results suggest that the native I(K) in rat mesenteric artery SMCs might be generated by heteromultimerization of Kv genes.
Recent work from this laboratory demonstrated potent inhibition of apoptosis in human alveolar epithelial cells (AECs) by the angiotensin-converting enzyme inhibitor captopril [B. D. Uhal, C. Gidea, R. Bargout, A. Bifero, O. Ibarra-Sunga, M. Papp, K. Flynn, and G. Filippatos. Am. J. Physiol. 275 (Lung Cell. Mol. Physiol. 19): L1013-L1017, 1998]. On this basis, we hypothesized that apoptosis in this cell type might be induced by angiotensin II (ANG II) through its interaction with the ANG II receptor. Purified ANG II induced dose-dependent apoptosis in both the human AEC-derived A549 cell line and in primary type II pneumocytes isolated from adult Wistar rats as detected by nuclear and chromatin morphology, caspase-3 activity, and increased binding of annexin V. Apoptosis also was induced in primary rat AECs by purified angiotensinogen. The nonselective ANG II-receptor antagonist saralasin completely abrogated both ANG II- and angiotensinogen-induced apoptosis at a concentration of 50 microgram/ml. With RT-PCR, both cell types expressed the ANG II-receptor subtypes 1 and 2 and angiotensin-converting enzyme (ACE). The nonthiol ACE inhibitor lisinopril blocked apoptosis induced by angiotensinogen, but not apoptosis induced by purified ANG II. These data demonstrate the presence of a functional ANG II-dependent pathway for apoptosis in human and rat AECs and suggest a role for the ANG II receptor and ACE in the induction of AEC apoptosis in vivo.
Earlier work from this laboratory found that fibroblasts isolated from fibrotic human lung [human interstitial pulmonary fibrosis (HIPF)] secrete a soluble inducer(s) of apoptosis in alveolar epithelial cells (AECs) in vitro [B. D. Uhal, I. Joshi, A. True, S. Mundle, A. Raza, A. Pardo, and M. Selman. Am. J. Physiol. 269 (Lung Cell. Mol. Physiol. 13): L819-L828, 1995]. The cultured human fibroblast strains most active in producing the apoptotic activity contained high numbers of stellate cells expressing alpha-smooth muscle actin, a myofibroblast marker. The apoptotic activity eluted from gel-filtration columns only in fractions corresponding to proteins. Western blotting of the protein fraction identified immunoreactive angiotensinogen (ANGEN), and two-step RT-PCR revealed expression of ANGEN by HIPF fibroblasts but not by normal human lung fibroblasts. Specific ELISA detected angiotensin II (ANG II) at concentrations sixfold higher in HIPF-conditioned medium than in normal fibroblast-conditioned medium. Pretreatment of the concentrated medium with purified renin plus purified angiotensin-converting enzyme (ACE) further increased the ELISA-detectable ANG II eightfold. Apoptosis of AECs in response to HIPF-conditioned medium was completely abrogated by the ANG II receptor antagonist saralasin (50 microg/ml) or anti-ANG II antibodies. These results identify the protein inducers of AEC apoptosis produced by HIPF fibroblasts as ANGEN and its derivative ANG II. They also suggest a mechanism for AEC death adjacent to HIPF myofibroblasts [B. D. Uhal, I. Joshi, C. Ramos, A. Pardo, and M. Selman. Am. J. Physiol. 275 (Lung Cell. Mol. Physiol. 19): L1192-L1199, 1998].
Recent works from this laboratory demonstrated potent inhibition of Fas-induced apoptosis in alveolar epithelial cells (AECs) by the angiotensin-converting enzyme (ACE) inhibitor captopril [B. D. Uhal, C. Gidea, R. Bargout, A. Bifero, O. Ibarra-Sunga, M. Papp, K. Flynn, and G. Filippatos. Am. J. Physiol. 275 (Lung Cell. Mol. Physiol. 19): L1013-L1017, 1998] and induction of dose-dependent apoptosis in AECs by purified angiotensin (ANG) II [R. Wang, A. Zagariya, O. Ibarra-Sunga, C. Gidea, E. Ang, S. Deshmukh, G. Chaudhary, J. Baraboutis, G. Filippatos and B. D. Uhal. Am. J. Physiol. 276 (Lung Cell. Mol. Physiol. 20): L885-L889, 1999]. These findings led us to hypothesize that the synthesis and binding of ANG II to its receptor might be involved in the induction of AEC apoptosis by Fas. Apoptosis was induced in the AEC-derived human lung carcinoma cell line A549 or in primary AECs isolated from adult rats with receptor-activating anti-Fas antibodies or purified recombinant Fas ligand, respectively. Apoptosis in response to either Fas activator was inhibited in a dose-dependent manner by the nonthiol ACE inhibitor lisinopril or the nonselective ANG II receptor antagonist saralasin, with maximal inhibitions of 82 and 93% at doses of 0.5 and 5 microg/ml, respectively. In both cell types, activation of Fas caused a significant increase in the abundance of mRNA for angiotensinogen (ANGEN) that was unaffected by saralasin. Transfection with antisense oligonucleotides against ANGEN mRNA inhibited the subsequent induction of Fas-stimulated apoptosis by 70% in A549 cells and 87% in primary AECs (both P < 0.01). Activation of Fas increased the concentration of ANG II in the serum-free extracellular medium 3-fold in primary AECs and 10-fold in A549 cells. Apoptosis in response to either Fas activator was completely abrogated by neutralizing antibodies specific for ANG II (P < 0.01), but isotype-matched nonimmune immunoglobulins had no significant effect. These data indicate that the induction of AEC apoptosis by Fas requires a functional renin-angiotensin system in the target cell. They also suggest that therapeutic control of AEC apoptosis is feasible through pharmacological manipulation of the local renin-angiotensin system.
OBJECTIVE: To evaluate the efficacy and safety of a 1-week intermittent itraconazole dosing schedule for onychomycosis. METHODS: In this multicenter, open-label study, 646 patients received itraconazole 200 mg twice daily for 1 week/month, followed by 3 weeks without therapy. Patients with fingernail infections received 2 treatment cycles, patients with toenail or combined toenail and fingernail infections received 3 cycles. Efficacy was evaluated at week 9 (2-month regimen), week 13 (3-month regimen) and 3, 6 or 9 (toenails only) months after completion of therapy. RESULTS: Clinical and mycologic cure rates for fingernails were greater than 90% 6 months after completion of 2 treatment cycles. Clinical and mycologic cure rates for toenails were 84 and 98%, respectively, 9 months after completion of 3 cycles. Treatment was well tolerated; adverse events (mostly mild) occurred in 4.6% of patients. CONCLUSION: A 1-week intermittent itraconazole dosing regimen is a safe and effective treatment for onychomycosis.
OBJECTIVE: The changing effectiveness of a treatment program for dual-diagnosis patients was evaluated over a 2-year period with the use of a sequential study group design. METHOD: The treatment outcome of 179 consecutively enrolled patients with chronic psychotic illness and comorbid substance dependence who entered a specialized day hospital dual-diagnosis treatment program from Sept. 1, 1994, to Aug. 31, 1996, was evaluated. The 24 months were divided into four successive 6-month periods for comparing the evolving effectiveness of the program for groups of patients entering the day hospital during these four periods. Treatment attendance, hospital utilization, and twice weekly urine toxicology analyses were used as outcome measures. RESULTS: The initial treatment engagement rate, defined as at least 2 days of attendance in the first month, increased significantly from group 1 to group 4, more than doubling. Thirty-day and 90-day treatment retention rates also substantially increased from group 1 to group 4. More patients had no hospitalization in the 6 months after entering the day hospital program than in the 6 months before entering the day hospital program. Urine toxicology monitoring indicated that the patients in group 4 were more likely than those in group 1 to remain abstinent at follow-up. CONCLUSIONS: The evolving clinical effectiveness of a developing program can be quantified by using a sequential group comparison design. The sequential outcome improvements may be related to the incremental contributions of assertive case management and skills training for relapse prevention.
OBJECTIVE: The primary intent of this study was to compare the efficacy and safety of olanzapine and placebo in the treatment of acute mania. METHOD: The design involved a random-assignment, double-blind, placebo-controlled parallel group study of 3 weeks' duration. After a 2- to 4-day screening period, qualified patients were assigned to either olanzapine (N = 70) or placebo (N = 69). Patients began double-blind therapy with either olanzapine, 10 mg, or placebo given once per day. After the first day of treatment, the daily dose could be adjusted upward or downward, as clinically indicated, by one capsule (olanzapine, 5 mg/day) within the allowed range of one to four capsules. The primary efficacy measure in the protocol was defined as a change from baseline to endpoint in total score on the Young Mania Rating Scale. Clinical response was defined a priori as a decrease of 50% or more from baseline in Young Mania Rating Scale total score. RESULTS: The olanzapine group experienced significantly greater mean improvement in Young Mania Rating Scale total score than the placebo group. On the basis of the clinical response criteria, significantly more olanzapine-treated patients (48.6%) responded than those assigned to placebo (24.2%). Somnolence, dizziness, dry mouth, and weight gain occurred significantly more often with olanzapine. There were no statistically significant differences between the olanzapine-treated and placebo-treated patients with respect to measures of parkinsonism, akathisia, and dyskinesias. No discontinuations of treatment due to adverse events occurred in the olanzapine treatment group. CONCLUSIONS: The results from this study suggest that compared with placebo, olanzapine has superior efficacy for the symptoms of acute mania.