Biomedical subjects

Hongwei Zhao

Publications and source records attributed to Hongwei Zhao.

At least 19 recordsLinked to original sources

PubMed2021

Spray-induced gene silencing for disease control is dependent on the efficiency of pathogen RNA uptake.

Recent discoveries show that fungi can take up environmental RNA, which can then silence fungal genes through environmental RNA interference. This discovery prompted the development of Spray-Induced Gene Silencing (SIGS) for plant disease management. In this study, we aimed to determine the efficacy of SIGS across a variety of eukaryotic microbes. We first examined the efficiency of RNA uptake in multiple pathogenic and non-pathogenic fungi, and an oomycete pathogen. We observed efficient double-stranded RNA (dsRNA) uptake in the fungal plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, Aspergillus niger and Verticillium dahliae, but no uptake in Colletotrichum gloeosporioides, and weak uptake in a beneficial fungus, Trichoderma virens. For the oomycete plant pathogen, Phytophthora infestans, RNA uptake was limited and varied across different cell types and developmental stages. Topical application of dsRNA targeting virulence-related genes in pathogens with high RNA uptake efficiency significantly inhibited plant disease symptoms, whereas the application of dsRNA in pathogens with low RNA uptake efficiency did not suppress infection. Our results have revealed that dsRNA uptake efficiencies vary across eukaryotic microbe species and cell types. The success of SIGS for plant disease management can largely be determined by the pathogen's RNA uptake efficiency.

Ascomycota↗

PubMed2006

Regression analysis of mean quality-adjusted lifetime with censored data.

In clinical trials of chronic diseases such as acquired immunodeficiency syndrome, cancer, or cardiovascular diseases, the concept of quality-adjusted lifetime (QAL) has received more and more attention. In this paper, we consider the problem of how the covariates affect the mean QAL when the data are subject to right censoring. We allow a very general form for the mean model as a function of covariates. Using the idea of inverse probability weighting, we first construct a simple weighted estimating equation for the parameters in our mean model. We then find the form of the most efficient estimating equation, which yields the most efficient estimator for the regression parameters. Since the most efficient estimator depends on the distribution of the health history processes, and thus cannot be estimated nonparametrically, we consider different approaches for improving the efficiency of the simple weighted estimating equation using observed data. The applicability of these methods is demonstrated by both simulation experiments and a data example from a breast cancer clinical trial study.

Breast Neoplasms↗

PubMed2006

The cost effectiveness of implantable cardioverter-defibrillators: results from the Multicenter Automatic Defibrillator Implantation Trial (MADIT)-II.

OBJECTIVES: We sought to evaluate the cost implications of the implantable cardioverter-defibrillator (ICD), using utilization, cost, and survival data from the Multicenter Automatic Defibrillator Implantation Trial (MADIT)-II. BACKGROUND: This trial showed that prophylactic implantation of a defibrillator reduces the rate of mortality in patients who experienced a previous myocardial infarction and low left ventricular ejection fraction. Given the size of the eligible population, the cost effectiveness of the ICD has substantial implications. METHODS: Our research comprises the cost-effectiveness component of the randomized controlled trial, MADIT-II, based on utilization, cost, and survival information from 1,095 U.S. patients who were assigned randomly to receive an ICD or conventional medical care. Utilization data were converted to costs using a variety of national and hospital-specific data. The incremental cost-effectiveness ratio (iCER) was calculated as the difference in discounted costs divided by the difference in discounted life expectancy within 3.5 years. Secondary analyses included projections of survival (using three alternative assumptions), corresponding cost assumptions, and the resulting cost-effectiveness ratios until 12 years after randomization. RESULTS: During the 3.5-year period of the study, the average survival gain for the defibrillator arm was 0.167 years (2 months), the additional costs were 39,200 dollars, and the iCER was 235,000 dollars per year-of-life saved. In three alternative projections to 12 years, this ratio ranged from 78,600 dollars to 114,000 dollars. CONCLUSIONS: The estimated cost per life-year saved by the ICD in the MADIT-II study is relatively high at 3.5 years but is projected to be substantially lower over the course of longer time horizons.

Cost-Benefit Analysis↗

PubMed2006

Laser flash photolysis study on antioxidant properties of hydroxycinnamic acid derivatives.

The antioxidant properties of hydroxycinnamic acid derivatives (HCA) were studied by laser flash photolysis. The transient species with maximum absorption at 360 nm were assigned to the phenoxyl radical of HCA. The SO (4) (.-) induced oxidation of HCA was also investigated. It was shown that the interaction of SO (4) (.-) with HCA resulted in the formation of HCA phenoxyl radicals with rate constants of 2.0-3.9 x 10(9 )M(-1) s(-1). The reactions of HCA with triplet state of benzophenone were analyzed and quenching rate constants of 4.3-7.8 x 10(9 )M(-1) s(-1) were determined.

Absorption↗

PubMed2006

Spectroscopic studies on the interaction between riboflavin and albumins.

The interactions between riboflavin (RF) and human and bovine serum albumin (HSA and BSA) were studied by using absorption and fluorescence spectroscopic methods. Intrinsic fluorescence emission spectra of serum albumin in the presence of RF show that the endogenous photosensitizer acts as a quencher. The decrease of fluorescence intensity at about 350 nm is attributed to changes in the environment of the protein fluorophores caused by the ligand. The quenching mechanisms of albumins by RF were discussed. The binding constants and binding site number were obtained at various temperatures. The distance between albumins and RF in the complexes suggests that the primary binding site for RF is close to tryptophan residue (Trp214) of HSA and Trp212 of BSA. The hydration process of albumins has also been discussed.

Absorption↗

PubMed2006

Preparation and characterization of liposomes-in-alginate (LIA) for protein delivery system.

This paper describes the preparation and characterization of a novel drug delivery system for protein, liposomes-in-alginate (LIA) of biodegradable polymers, which is conceived from a combination of the polymer and the lipid-based delivery systems. LIA were prepared by first entrapping bovine serum albumin (BSA), a model protein within multivesicular liposomes (MVLs) by double emulsification process, which are then encapsulated within alginate hydrogel microcapsule, with untrapped BSA which are added during preparation of MVLs. Factors impacting encapsulation efficiency of MVLs are investigated and release of protein from the microcapsules in vitro is studied. At the same time, characterization of MVLs, microcapsules encapsulated protein formulation and integrality analyse of BSA in microcapsules are also studied, with the aim of improving the entrapment efficiency and prolonging release time. It is found that encapsulation efficiency and size of MVLs are affected by the composition and fabrication parameters of LIA. The data also show LIA have high encapsulation efficiency (up to 95%), little chemical change in drug caused by the formulation process, narrow particle size distribution and spherical particle morphology. Drug release assays conducted in vitro indicates that these formulations provide sustained release of encapsulated drug over a period, about 2 weeks.

Alginates↗

PubMed2006

The 73 kD subunit of the cleavage and polyadenylation specificity factor (CPSF) complex affects reproductive development in Arabidopsis.

The cleavage and polyadenylation specificity factor (CPSF) is an important multi-subunit component of the mRNA 3'-end processing apparatus in eukaryotes. The Arabidopsis genome contains five genes encoding CPSF homologues (AtCPSF160, AtCPSF100, AtCPSF73-I, AtCPSF73-II and AtCPSF30). These CPSF homologues interact with each other in a way that is analogous to the mammalian CPSF complex or their yeast counterparts, and also interact with the Arabidopsis poly(A) polymerase (PAP). There are two CPSF73 like proteins (AtCPSF73-I and AtCPSF73-II) that share homology with the 73 kD subunit of the mammalian CPSF complex. AtCPSF73-I appears to correspond to the functionally characterized mammalian CPSF73 and its yeast counterpart. AtCPSF73-II was identified as a novel protein with uncharacterized protein homologues in other multicellular organisms, but not in yeast. Both of the AtCPSF73 proteins are targeted in the nucleus and were found to interact with AtCPSF100. They are also essential since knockout or knockdown mutants are lethal. In addition, the expression level of AtCPSF73-I is critical for Arabidopsis development because overexpression of AtCPSF73-I is lethal. Interestingly, transgenic plants carrying an additional copy of the AtCPSF73-I gene, that is, the full-length cDNA under the control of its native promoter, appeared normal but were male sterile due to delayed anther dehiscence. In contrast, we previously demonstrated that a mutation in the AtCPSF73-II gene was detrimental to the genetic transmission of female gametes. Thus, two 73 kD subunits of the AtCPSF complex appear to have special functions during flower development. The important roles of mRNA 3'-end processing machinery in modulating plant development are discussed.

Arabidopsis↗

PubMed2006

Predictors of conviction and sentencing of DWI offenders in a New Mexico County.

OBJECTIVE: To analyze predictors of conviction and dismissal of individuals charged with DWI, and predictors of the sentences of those who are convicted. METHODS: Data come from the Citation Tracking System of the State of New Mexico's Motor Vehicle Division and includes information on all individuals who were arrested for DWI in San Juan County between August 1994 and December 2000. Independent variables were: age, gender, race/ethnicity, waiver of right to an attorney, court of arraignment, year of arrest, BAC, and number of prior DWI arrests. Dependent variables were: (1) conviction or dismissal, (2) jail or no jail, (3) incarceration/treatment or not, (4) fine or no fine, (5) length of jail sentence, (6) waived right of attorney, and (7) magnitude of fine. Multiple linear and logistic regression was used in the analyses. RESULTS: Use of an attorney is associated with reduced likelihood of conviction and, if convicted, in reduced likelihood of jail sentence and reduced jail time, but greater likelihood and magnitude of a fine. Native Americans were more likely than Hispanics and non-Hispanic whites to waive their right to an attorney. Native Americans were most likely to be sentenced to the detention/treatment program. BAC and number of prior arrests were each positively associated with increased likelihood of conviction and more severe sentences. There is also substantial variability in severity of sentencing among courts. CONCLUSION: Likelihood of conviction and severity of sentences are both determined by extra-legal factors, resulting in inconsistent application of the law. This may in turn contribute to a lack of compliance with laws related to DWI.

Adolescent↗

PubMed2006

Estimating incremental cost-effectiveness ratios and their confidence intervals with differentially censored data.

With medical costs escalating over recent years, cost analysis is being conducted more and more to assess economic impact of new treatment options. An incremental cost-effectiveness ratio (ICER) is a measure that assesses the additional cost for a new treatment for each additional unit of effectiveness, such as saving 1 year of life. In this article, we consider cost-effectiveness analysis for new treatments evaluated in a randomized clinical trial setting with staggered entries. In particular, the censoring times are different for cost and survival data. We propose a method for estimating the ICER and obtaining its confidence interval when differential censoring exists. Simulation experiments are conducted to evaluate our proposed method. We also apply our methods to a clinical trial example comparing the cost-effectiveness of implanted defibrillators with conventional therapy for individuals with reduced left ventricular function after myocardial infarction.

Biometry↗

PubMed2006

A pilot study to assess the influence of tai chi chuan on functional capacity among breast cancer survivors.

Treatment of breast cancer can significantly diminish functional capacity in patients months and even years after the completion of treatments. Tai chi chuan (TCC) is a moderate form of exercise that may be an effective therapy for improving functional capacity among breast cancer survivors. We sought to provide pilot data comparing the efficacy of TCC and psychosocial therapy (PST; physical activity control) for improving functional capacity among breast cancer survivors post treatment. Twenty-one women who had completed treatment of breast cancer were randomized to receive TCC or PST 3 times/wk for 12 weeks. Functional capacity was assessed at baseline and at 12 weeks. The TCC group demonstrated significant improvement in functional capacity (specifically aerobic capacity, muscular strength, and flexibility) whereas the PST group showed significant improvement in flexibility only. These data suggest that TCC may be an efficacious intervention for enhancing functional capacity among breast cancer survivors and may support the need for larger randomized, controlled clinical trials to further elucidate these relationships.

Adult↗

PubMed2005

5-Hydroxytryptamine-receptor antagonists versus prochlorperazine for control of delayed nausea caused by doxorubicin: a URCC CCOP randomised controlled trial.

BACKGROUND: Despite widespread use of short-acting antagonists for the 5-hydroxytryptamine (5-HT) receptor, about 50% of patients given moderately emetogenic chemotherapy have delayed nausea. We aimed to assess whether a 5-HT-receptor antagonist was more effective than was prochlorperazine for control of delayed nausea and delayed vomiting caused by doxorubicin. METHODS: 691 patients who previously had not had chemotherapy and who were scheduled to receive doxorubicin were given a short-acting 5-HT-receptor antagonist and dexamethasone before doxorubicin (day 1), and were randomly assigned to one of three regimens for days 2 and 3: 10 mg prochlorperazine taken orally every 8 h; any first-generation 5-HT-receptor antagonist (except palonosetron) taken as standard dose intravenously or orally; or 10 mg prochlorperazine taken as needed. Nausea and vomiting were assessed by use of a home record. The primary endpoint was mean severity of delayed nausea. The secondary endpoint was quality of life. Analyses were done by intention to treat. FINDINGS: 519 (77%) of the 671 evaluable patients had delayed nausea, with a mean severity of 3.33 (95% CI 3.22-3.44). 161 (71%) of 226 patients assigned prochlorperazine every 8 h reported delayed nausea (mean severity 3.37 [3.16-3.58]), as did 179 (79%) of 226 patients assigned 5-HT-receptor antagonists (3.29 [3.09-3.48]) and 179 (82%) of 219 patients assigned prochlorperazine as needed (3.33 [3.15-3.50]); groups did not differ in mean severity (p=0.853, one-way ANOVA). Patients allocated prochlorperazine every 8 h had less delayed nausea than did those allocated 5-HT-receptor antagonists (p=0.05, t test) and those allocated prochlorperazine as needed (p=0.009, t test). INTERPRETATION: Short-acting 5-HT-receptor antagonists are no better than is prochlorperazine in control of delayed nausea caused by doxorubicin. Although fewer patients taking prochlorperazine report delayed nausea, the proportion was unacceptably high.

Antiemetics↗

PubMed2005

Factors affecting protein release from microcapsule prepared by liposome in alginate.

A new type of drug delivery system that microcapsule was prepared by liposome in alginate on this paper, bovine serum albumin (BSA) as an model drug. Influences of liposomes composition and multivalent cations on morphology, enveloped rate, integrality and release in vitro from microcapsule were investigated. The results are showed that Ca2+ and Ba2+ made hydrogels form easier than Al3+ and particle size were uniform, circular, but microcapsule prepared by Al3+ was flat circular and easily adhere to each other. Particle size of all microcapsules was 200-300 microm after dryness, measured by vernier calliper. BSA enveloped rate prepared by PC/PG/Chol and Ba2+ was highest, 77.65%, and also correlative to concentration of lipid. At the other hand, Ba2+ microcapsule prepared by liposome in alginate has not an initial burst and have a good performance on delivering protein. Integrality of protein was not destroyed after encapsulated.

Alginates↗

PubMed2005

Microencapsulation peptide and protein drugs delivery system.

Many methods were used to devise peptide and protein drugs delivery system (DDS). Because of their relatively large size, they have low transdermal bioavailabilities. In systemic delivery of proteins, biodegradable material as parenteral depot formulation occupy an important place because of several aspects like protection of sensitive proteins from degradation, prolonged or modified release, pulsatile release patterns. The main objective in developing controlled release protein injectables is avoidance of regular invasive doses which in turn provide patient compliance, comfort as well as control over blood levels. This review article presents the outstanding contributions in field of microencapsulation as protein delivery systems and different approaches of protein delivery are described. Then discusses how these advances may be applied to resolve the challenges face the development of microcapsule for the controllable delivery of protein drugs.

Alginates↗

PubMed2005

Interrater agreement in the assessment of motor manifestations of Huntington's disease.

With prospects improving for experimental therapeutics aimed at postponing the onset of illness in preclinical carriers of the Huntington's disease (HD) gene, we assessed agreement among experienced clinicians with respect to the motor manifestations of HD, a relevant outcome measure for preventive trials in this population. Seventy-five clinicians experienced in the evaluation of patients with early HD and six non-clinicians were shown a videotape compiled from the film archives of the United States-Venezuela Collaborative HD Research Project. Observers were asked to rate a 2-3-minute segment of the motor examination for each of 17 at-risk subjects. The rating scale ranged from 0 (normal) to 4 (unequivocal extrapyramidal movement disorder characteristic of HD). As measured by a weighted kappa statistic, there was substantial agreement among the 75 clinicians in the judgment of unequivocal motor abnormalities comparing scale ratings of 4 with ratings that were not 4 (weighted kappa = 0.67; standard error (SE) = 0.09). Agreement among the non-clinicians was only fair (weighted kappa = 0.28; SE = 0.10). Even under the artificial conditions of a videotape study, experienced clinicians show substantial agreement about the signs that constitute the motor manifestations of illness in subjects at risk for HD. We expect these findings to translate to a similar level of interobserver agreement in the clinical trial setting involving experienced investigators examining live patients.

Basal Ganglia Diseases↗

PubMed2005

Variations in jail sentences and the probability of re-arrest for driving while intoxicated.

OBJECTIVE: The probability of re-arrest for driving while intoxicated (DWI) is compared for four different groups of individuals classified by whether the individual was convicted and, if so, the type of sentence received. METHOD: Subsequent re-arrests for DWI were examined for all individuals whose index arrest for DWI had occurred between 1994 and 2001 in a county in New Mexico. The groups included (1) those convicted as a result of the index arrest and sentenced to a 28-day jail/treatment program (N (#)=(#) 2,703); (2) all those not convicted as a result of the index arrest (N = 709); (3) those who were convicted but not sentenced to jail (N = 1,047); and (4) those convicted and sentenced to jail (N = 1,290). RESULTS: Adjusting for covariates of BAC, number of prior arrests, ethnicity, age, and sex, the probability of not being re-arrested was greatest among those sentenced to the jail/treatment program (Group 1), next highest in the two groups convicted but not sentenced to jail/treatment (Groups 3 and 4), and lowest in the group that was not convicted (Group 2). Length of jail sentence among people convicted but not sentenced to the jail/treatment program was unrelated to the probability of re-arrest. CONCLUSION: Conviction for DWI, regardless of the sentence, appears to reduce the probability of re-arrest, and being sentenced to a multi-modal treatment/incarceration program further reduces the probability of re-arrest. However, the other types of sentences do not appear to differ in their impact on probability of re-arrest.

Adult↗

PubMed2004

The prevention paradox, traffic safety, and driving-while-intoxicated treatment.

BACKGROUND: In San Juan County, New Mexico, a 28-day jail/treatment program for first-time driving-while-intoxicated (DWI) offenders was established in 1994 to reduce both DWI recidivism and alcohol-related crashes. This paper assesses the impact of the program on both outcomes. METHODS: The data are composed of driving records of all people arrested for DWI in San Juan County from August 1994 through December 2001. Subsequent re-arrests and crashes were analyzed to compare people who had been sentenced to the jail/treatment program and those who had not. Kaplan-Meier survival curves and Cox proportional hazards regression analyses were used. Covariates included age, gender, blood alcohol content (BAC), number of prior arrests, and ethnicity (Native American, non-Hispanic white, and Hispanic). RESULTS: Re-arrest rates were significantly lower for the treatment than the nontreatment group. Each of the three major ethnic groups showed similar effects. This was not observed for subsequent alcohol-related crashes, possibly as a result of insufficient numbers. BAC and number of previous arrests were, however, significant risk factors for subsequent crashes. Finally, although BAC and previous arrests were important risk factors for subsequent crashes, the vast majority of subsequent alcohol-related crashes occurred among people in the intermediate risk ranges. CONCLUSIONS: The jail/treatment program is effective in reducing the probability of DWI re-arrests. The evidence with respect to crashes is equivocal. That most crashes occur to people in the intermediate risk range exemplifies the prevention paradox, and means that the courts, which deal most severely with high-risk individuals, cannot be expected to have a major impact on alcohol-related crashes.

Accidents, Traffic↗

PubMed2003

Using local correlation in kernel-based smoothers for dependent data.

We consider the general problem of smoothing correlated data to estimate the nonparametric mean function when a random, but bounded, number of measurements is available for each independent subject. We propose a simple extension to the local polynomial regression smoother that retains the asymptotic properties of the working independence estimator, while typically reducing both the conditional bias and variance for practical sample sizes, as demonstrated by exact calculations for some particular models. We illustrate our method by smoothing longitudinal functional decline data for 100 patients with Huntington's disease. The class of local polynomial kernel-based estimating equations previously considered in the literature is shown to use the global correlation structure in an apparently detrimental way, which explains why some previous attempts to incorporate correlation were found to be asymptotically inferior to the working independence estimator.

Biometry↗

PubMed2002

Rearrest rates after incarceration for DWI: a comparative study in a southwestern US county.

OBJECTIVES: This study was undertaken to assess a 28-day detention and treatment program's effect, in a multiethnic county with high rates of alcohol-related arrests and crashes, on first-time offenders sentenced for driving while impaired (DWI). METHODS: We used comparison of baseline characteristics, survival curves of subsequent arrest, and Cox proportional hazards regression to examine probability of rearrest of those sentenced and those not sentenced to the program. RESULTS: Probability of not being rearrested was significantly higher for the treatment group after adjustment for covariates. At 5 years, probability of not being rearrested for the treatment vs the nontreatment group was 76.6% vs 59.9%. CONCLUSIONS: Results suggest that this county's program has significantly affected rearrest rates for Native Americans, Hispanics, and non-Hispanic Whites.

Accidents, Traffic↗