A comparative study of scientific collaborations in medical informatics, health information management, medical librarianship, and information sciences among Iranian research communities: A bibliometric study

Background and Aim

Scientific collaborations play a vital role in advancing research in various disciplines, including medical informatics, health information management, medical librarianship, and information sciences. This study aims to provide an overview of Iranian researchers' scientific output in three disciplines and their collaboration networks.

Methods

The study utilized data from Scopus database and analyzed 2086 records of Iranian researchers' research outcomes over 10 years. Each article's citations were averaged to determine its impact factor. The study also reviewed the number of articles and citations in the past decade.

Results

The findings show that scientific output in the disciplines of medical informatics, health information management, medical librarianship, and information sciences has significantly increased among Iranian researchers in the past decade. The analysis of collaboration networks indicates a strong connection between these disciplines, with medical informatics having the highest degree of collaboration.

Conclusion

This study provides valuable insights into the scientific collaborations among Iranian researchers in medical informatics, health information management, medical librarianship, and information sciences. The findings can be used to inform future research and collaboration initiatives in these disciplines. The results suggest that Iranian researchers in these disciplines have made significant progress in scientific output and collaboration. However, further efforts are required to improve the quality and impact of their research.

Scientometric assessment of scientific documents published in 2020 on herbal medicines used for COVID-19

Objective

Many studies have suggested herbal medicines as alternatives or adjuvants to modern drugs for COVID-19. Their scientometric analyses can provide a scientific overview of this topic.

Materials and methods

Web of Science (WOS) and Scopus were searched for articles on the use of herbal medicines in COVID-19 published until 26 October 2020. Collected data were analyzed for document type, subject area, top journal, citation number, and authors’ collaboration network using VOSviewer 1.6.15, ScientoPy 2.0.3, Gephi 0.9.2, and SPSS 15 statistical tools.

Results

After screening the 3185 retrieved records, 378 and 849 records, respectively from WOS and Scopus, remained for quantity analysis. Original and review articles were the two main types of papers in both databases. Top subject areas were drug and medicine, respectively in the WOS and Scopus databases. The top three productive countries in the field were China, the US, and India. The most cited article was a practice guideline in both databases. “Journal of Biomolecular Structure Dynamics” in WOS and “Chinese Traditional and Herbal Drugs” in Scopus were the top journals. Top keywords included “COVID-19″ and “Traditional Chinese Medicine”. US authors had the highest collaboration with other authors.

Conclusions

The current study provides a snapshot of the quantity and characteristics of published scholarly documents in recent months in the intersection of herbal medicines and COVID-19. Our findings help scientists to find the existing gaps, identify the active authors and scientific institutes to collaborate with and use their experience to produce new knowledge in the future.

The dietary inflammatory index is associated with aerobic performance and anthropometric measures of marines

Evidence propose that dietary intake affects physical performance and body composition. The present study aimed to determine the relationship between dietary inflammatory index (DII) with physical function and anthropometric indices in the marine. This cross-sectional study was performed on 300 males aged 18 to 45 years serving in the Navy. A general questionnaire was used to collect demographic data of participants. Also, the anthropometric indices (height, weight, waist circumference, and hip circumference) were measured to calculate a body shape index (ABSI), abdominal volume index (AVI), body adiposity index (BAI), and conicity as new anthropometric indices. Moreover, the 12-min Cooper, sit up, pull up, and push up were used to assess physical performance. Food intake over the past year was assessed using a 147-item food frequency questionnaire, and then the DII score was calculated for each subject. Aerobic performance was assessed using the Cooper test. Also, the repetitions of sit up, pull up and push up in 1 minute were recorded to assess muscular endurance. The present study showed that the increase in DII is directly related to body mass index (BMI) (P=0.04), body fat percentage (P=0.03), and BAI (P=0.010) and inversely related to VO2max (P=0.001). However, after adjusting for the effect of energy intake in regression model, only the association between DII and VO2max was statistically significant (β=-1.69, standard error=0.67, P=0.01). The increase in the dietary inflammatory potential is associated to a higher BMI and body adiposity and a lower aerobic capacity in military personnel. However, the observed relationship between DII and anthropometric indices seems to be influenced by the energy intake. Further well-designed studies with a prospective method are warranted.

Ranking of Iranian medical universities based on altmetric indices

This study was aimed at evaluating the Iranian medical universities’ rankings and altmetric indices in ResearchGate and Academia.edu. This cross-sectional analytical study was conducted using a scientometric method. Social networking measures were collected in MS Excel from January to February 2017. Data were analysed using SPSS software and the Spearman, chi-square and Kendall rank coefficient tests. Ranking information and altmetric indices of 50 Iranian medical universities were collected and analysed. All of the type-1 medical universities have been presented in the Academia.edu and ResearchGate social networks. A statistically significant relationship ( P < 0.05) has been found between the ranking systems of the universities with altmetric indicators, such as the number of members in both social networks, the number of publications and the total RG score in ResearchGate. In addition, there was a significant correlation between the ranking of medical universities based on the H-index of science metrics with their presence in the ResearchGate social network ( P < 0.05). The results of this study reveal a relationship between the universities’ ranking systems and altmetric indicators. These findings emphasise the necessity of increasing the presence of faculty members in social network activities in disseminating and sharing knowledge.

New perspectives of quercetin and vitamin C effects on fibronectin-binding integrins and chemokine receptors in prostate cancer cell lines

OBJECTIVES

The aim of this study is to investigate the effect of two abundant dietary supplements, quercetin and vitamin C on some factors involved in metastasis and proliferation of prostate cancer, which are resistant to conventional chemotherapies in late stages.

BACKGROUND

Bone and brain are two common sites of metastases in prostate cancer, nevertheless the factors involved in their metastatic pathways are not well understood.

METHODS

The effect of quercetin (75µM) and vitamin C (100 µM) on CXCR4, CXCR7 chemokine receptors, α4, α5 and β1 integrins, ki-67 proliferation marker and Vascular endothelial growth factor, VEGF was evaluated using Quantitative Reverse Transcription PCR (RT-qPCR).

RESULTS

The effect of quercetin and vitamin C alone was different on PC3 and DU145 prostate cancer cell lines, but sequential combination reduced significantly the expression of CXCR and CXCR7 chemokine receptors, α4, α5 and β1 integrin subunits, VEGF and Ki-67 proliferation markers in PC3 and DU145 cell lines.

CONCLUSION

Our results indicated the beneficial effect of quercetin and vitamin C on prostate cancer cells with different metastatic sites and their differential response to the treatment which in turn may lead us to reach suitable therapeutic outcomes to combat cancer (Fig. 3, Ref. 36).

Scientometric analyzing the output of researchers and organizations on COVID-19 for better conducting the scientific efforts: with a glance to endocrinology

Purpose

As COVID-19 spreads rapidly and could affect the people and also lead to their death, especially individuals with underlying diseases, such as diabetes, the research community is also active in publishing novel research about it. Analyzing scientific outputs in this topic can represent an overview of publications. For this purpose, this study was conducted to determine status of publishing research works related to COVID-19 and analyzing the all documents published and indexed in Web of Science database and illustrate the co-occurrence and co-authority of hot papers in this documents.

Methodology

Our search strategy was based on using the related key terms including COVID-19, coronavirus, SARS2, etc., to find out all the published scientific works related to coronavirus disease indexed in web of science (WoS) in 2020. We then extracted the all hot papers and especially hot papers in endocrinology category and analyzed them. The data saved and imported in VOSviewer and ScientoPy programs for analysis and illustration of our data. We have shown our analysis in the tables, figures and maps.

Results

Totally, 56,402 records and 309 hot papers were retrieved. 3 of these hot papers were in endocrinology category. The most common type of publication was original papers followed by editorial papers in the second rank. The country with the most published documents was the USA followed by China. The journals of "British Medical Journal" and "Journal of Medical Virology" were ranked as the first and second sources, respectively. The "Harvard University" was the top organization with high proportion of scientific publications and "the Lancet" was the top-ranked journal that published highly-cited papers.

Conclusion

The literature on COVID-19 is increasing with a high and fast growth. In this regard, there is a need to evaluate these publications once in a while and their results should be published to use this information for more effective management of future research works with emphasizes on the gaps of researches and more citable documents and allocation of budgets on more needed research and don't carry out the duplicates research. This would be helpful for prevention, control, and treatment of COVID-19 that is now among the most common topics in the world.

Visualization of knowledge flow in interpersonal scientific collaboration network endocrinology and metabolism research institute

Purpose

Research collaborations can help to increase scientific productivity. The purpose of the present study was to draw up the knowledge flow network of the Endocrinology and Metabolism Research Institute (EMRI) affiliated to Tehran University of Medical Sciences.

Methods

The present study is a descriptive cross-sectional study on the publications of the EMRI. Web of Science Core collection databases were searched for the EMRI publications between 2002 to November 2019. Besides, publications were classified and visualized based on authorships (institutes and country of affiliation), and keywords (co-occurrence and trend). Scientometric methods including VOSviewer and HistCite were used for descriptive statistics and data analysis.

Results

Total citations to the records were 47,528 and papers were published in 916 journals. The annual growth rate of publications and the citation was 14.2% and 18.9%, respectively. A total of 9466 authors from 136 countries collaborated in the publications. The co-authorship patterns showed that the average co-authorship and collaboration coefficient was 3.3 and 0.19.

Conclusion

Knowledge flow between EMRI researchers with international collaborations, engagement with leading countries, and interdisciplinary collaborations have an increasing trend. To develop a full picture of co-authorship, using social network analysis indicators are suggested for future studies.

The co-word analysis and visualization of a 10-year international research on drowning

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A meta-analysis of service quality of Iranian university libraries based on the LibQUAL model

Purpose

The purpose of this paper is to assess the quality of Iranian university libraries.

Design/methodology/approach

This first systematic review and meta-analysis were based on the PRISMA guidelines by searching in national and international databases from 2003 to January 2017 with standard Persian and English keywords. Data searching, extracting and quality appraising were completed by two researchers, independently. Any unexpected documents were assessed by a third expert researcher. Data were extracted in accordance with the “Strength of the Reporting of Observational Studies in Epidemiology” checklist after the final selection of appraised documents. Random effects size based on Cochrane test and I2 were used for combining the obtained results from different studies together by considering the heterogeneity of studies.

Findings

Based on the meta-analysis conducted in 25 (6.42 percent) included studies, the total sample size was estimated. According to three dimensions of LibQUAL, findings of current information control, affect of service and the library as a place were estimated as 5.37 [CI95%: 5.02, 5.73], 6.91 [CI95%: 5.56, 6.26], and 5.46 percent [CI95%: 5.2, 5.73], respectively. Also, mean of service adequacy and superiority gap are equal to 0.07 [CI95%: −0.22, 0.36] and −2.06 [CI95%: −2.89, −1.23], respectively. There was a significant correlation between three dimensions of service quality and service superiority gap of LibQUAL and geographical regions of Iran (p<0.01). Also, a significant correlation was found between the gaps of services and three aspects of LibQUAL model and published years through a meta-regression test (p<0.01).

Practical implications

The results obtained from the present study showed that users are relatively satisfied with the quality of services provided by Iranian university libraries. An improvement in the quality of library services can promote the scientific level of universities.

Originality/value

The results of the present systematic review and meta-analysis study demonstrate a vital connection between primary research studies and decision-making for policymakers in Iranian university libraries to increase quality services.

Reuse of spent FCC catalyst, waste serpentine and kiln rollers waste for synthesis of cordierite and cordierite-mullite ceramics

Spent fluid catalytic cracking (FCC) was gathered from several petrochemical plants and calcined in a rotary furnace between 1000 and 1100°C in order to remove sulphur and hydrocarbon based impurities. Calcining process on FCC led to formation of AlVO₄ ceramic phase, so converted the hazardous waste to non-hazardous applicable raw material. In this study, two ceramic bodies as cordierite and cordierite-mullite were synthesized with calcined spent FCC, waste serpentine, kiln rollers waste and high grade kaolin as raw materials. The XRD results showed that the cordierite and cordierite-mullite were synthesized successfully so that 96.4% of F1 (cordierite) sample fired at 1400°C was cordierite phase and F2 (cordierite-mullite) sample fired at 1450°C was completely cordierite and mullite phases. The synthesized cordierite and cordierite-mullite samples had lower porosity values and coefficient of thermal expansion (CTE) than similar industrial products. The negative CTE value that obtained from the cordierite sample up to 800°C is favorable for some applications. The considerable results of the synthesized cordierite and cordierite-mullite from this work present cost reduction of the two ceramic bodies production and may help to solve the environmental problems with the use of three waste sources in large scales.

Multiple model predictive control for optimal drug administration of mixed immunotherapy and chemotherapy of tumours

BACKGROUND

Mixed immunotherapy and chemotherapy of tumours is one of the most efficient ways to improve cancer treatment strategies. However, it is important to 'design' an effective treatment programme which can optimize the ways of combining immunotherapy and chemotherapy to diminish their imminent side effects. Control engineering techniques could be used for this.

METHODS

The method of multiple model predictive controller (MMPC) is applied to the modified Stepanova model to induce the best combination of drugs scheduling under a better health criteria profile. The proposed MMPC is a feedback scheme that can perform global optimization for both tumour volume and immune competent cell density by performing multiple constraints.

RESULTS

Although current studies usually assume that immunotherapy has no side effect, this paper presents a new method of mixed drug administration by employing MMPC, which implements several constraints for chemotherapy and immunotherapy by considering both drug toxicity and autoimmune. With designed controller we need maximum 57% and 28% of full dosage of drugs for chemotherapy and immunotherapy in some instances, respectively. Therefore, through the proposed controller less dosage of drugs are needed, which contribute to suitable results with a perceptible reduction in medicine side effects.

CONCLUSION

It is observed that in the presence of MMPC, the amount of required drugs is minimized, while the tumour volume is reduced. The efficiency of the presented method has been illustrated through simulations, as the system from an initial condition in the malignant region of the state space (macroscopic tumour volume) transfers into the benign region (microscopic tumour volume) in which the immune system can control tumour growth.

Beneficial effects of omega-3 and vitamin E coadministration on gene expression of SIRT1 and PGC1α and serum antioxidant enzymes in patients with coronary artery disease

BACKGROUND AND AIM

SIRT1 and PGC1α are two important genes, which play critical roles in regulating oxidative stress and inflammation processes. The study aimed assess the effects of coadministration of omega-3 and vitamin E supplements on SIRT1 and PGC1α gene expression and serum levels of antioxidant enzymes in coronary artery disease (CAD) patients.

METHODS AND RESULTS

Participants of this randomized controlled trial included 60 CAD male patients who were categorized into three groups: Group 1 received omega-3 (4 g/day) and vitamin E placebo (OP), group 2 omega-3 (4 g/day) and vitamin E (400 IU/day; OE), and group 3 omega-3 and vitamin E placebos (PP) for 2 months. Gene expression of SIRT1 and PGC1α in peripheral blood mononuclear cells (PBMCS) was assessed by reverse transcription polymerase chain reaction (RT-PCR). Furthermore, serum antioxidant enzyme and high-sensitivity C-reactive protein (hsCRP) levels were assessed at the beginning and end of the intervention. Gene expression of SIRT1 and PGC1α increased significantly in the OE group (P = 0.039 and P = 0.050, respectively). Catalase and hsCRP levels increased significantly in the OE and OP groups. However, glutathione peroxidase (GPX) and superoxide dismutase (SOD) levels did not statistically change in all groups. The total antioxidant capacity (TAC) increased significantly in the OE group (P = 0.009) but not in OP and PP groups.

CONCLUSION

Supplementation of omega-3 fatty acids in combination with vitamin E may have beneficial effects on CAD patients by increasing gene expression of SIRT1 and PGC1α and improving oxidative stress and inflammation in these patients.

A study of leptin serum concentrations in patients with major Beta-thalassemia

BACKGROUND

The aim of this study was to evaluate leptin serum levels in patients with major beta thalassemia which was also associated with their ferritin serum levels.

MATERIALS AND METHODS

This case-control study was performed on 90 children -6 months to 16 years old, in Zabol, Amir- al- Momenin Hospital. Patients were divided in two groups and were matched in age and sex. All Children were examined and those eligible children who had not known heart disease, iron deficiency anemia, kidney disease, diabetes, fever and systemic diseases were enrolled after taking the informed consent of their parents. After collecting the samples, leptin and ferritin levels of the serum were measured in two groups by ELISA method. Then, the data was analyzed by the related statistical tests and SPSS 20 software.

RESULTS

The mean of the serum levels of leptin and ferritin showed a significant difference in the case and control groups (P-value<0.05). An inverse statistical correlation was found for the serum levels of leptin and ferritin among the studied groups (P-value<0.05). Levels of leptin in the case group showed a significant gender difference (P-value<0.05), while based on BMI and age, no significant difference was observed for the serum levels of leptin in the case group.

CONCLUSION

Based on the results of this study, major thalassemia reduces serum levels of leptin regardless of age and body mass. The study also found an inverse statistical correlation between serum levels of leptin and ferritin among the studied people.

A comparative study of conjunctival autograft and minimally invasive pterygium surgery in primary pterygia

This study aimed at comparing the results of the Conjunctival Autograft Technique (CAG) and Minimally Invasive Pterygium Surgery (MIPS) in primary pterygium excisions. This was a prospective randomized clinical study performed during a one-year period (2009-2010). One hundred and twenty two patients with primary pterygium were randomized in 2 groups: group A (CAG) including 36 patients and group B (MIPS) including 86 patients. The two groups were compared considering the recurrence rate and probable complications of the procedures. Recurrences were detected in 4 patients (11.1%) in group A and 5 patients (5.8%) in group B with no significant difference in this regard (p = 0.447). No major complications occurred during the follow-up period. This study showed that acceptable recurrence- free rates could be achieved (albeit nonsignificant) using MIPS technique in patients with primary pterygium and can be considered as a good alternative in the surgical management of pterygia because of its simplicity and low surgical time.

Frequency of isolated hepatitis B core antibody in HIV-hepatitis C virus co-infected individuals

Association between isolated hepatitis B core antibody (anti-HBc) and hepatitis C virus (HCV) infection has been noted in HIV-infected individuals. This study describes the frequency of isolated anti-HBc and its possible value for the detection of HBV-DNA in HIV-infected patients with or without HCV co-infection. Ninety-two HIV-infected patients were enrolled in the study. Hepatitis B surface antigen (HBs Ag), anti-HBs, anti-HBc, anti-HCV, HIV viral load and CD4 count were tested in all subjects. Then we compared 63 subjects with HIV-HCV co-infection with 29 subjects with HIV infection alone regarding isolated anti-HBc (HBs Ag negative, anti-HBs negative and anti-HBc positive). The presence of HBV-DNA was determined by real-time polymerase chain reaction in serum samples of patients with isolated anti-HBc. Of 63 anti-HCV-positive patients, 18 subjects (28.6%, 95% [confidence interval] CI: 22.6-34.6%), and of 29 anti-HCV-negative patients, five subjects (17.2%, 95% CI: 11.5-22.9%) had isolated anti-HBc. HBV-DNA was detectable in three of 18 anti-HCV-positive patients (16.7%, 95% CI: 9.7-23.7%) and none of the anti-HCV-negative patients with isolated anti-HBc. Our study showed that individuals co-infected with HIV and HCV were more likely to have isolated anti-HBc than subjects with HIV alone. This investigation also demonstrates that the presence of isolated anti-HBc in HIV-HCV-infected individuals may reflect occult HBV infection in these patients.

Efficacy and long-term immunogenicity of hepatitis B vaccine in haemodialysis patients

BACKGROUND

Hepatitis B vaccine is effective in protection against hepatitis B virus (HBV) infection in haemodialysis (HD) patients, but the antibody response is variable in this population and the persistence of immunity in them remains largely unknown. In this study we aimed to evaluate the efficacy and long-term immunogenicity of hepatitis B vaccine in HD patients.

METHODS

In this study, we initially offered HBV vaccination as double dose, four vaccine series schedule (40 microg injections intramuscularly in the deltoid muscle at 0, 1, 2 and 6 months) to 54 HD patients who were negative for hepatitis B core antibody and did not receive any dose of HBV vaccine previously. Serum levels of hepatitis B surface antibody (anti-HBs) tested 1-2 months after completion of vaccination. Then we follow the patients up to 1 year after primary vaccination to evaluate the persistence of immunity (as indicated by serum levels of anti-HBs higher than or equal to 10 IU/l).

RESULTS

After primary vaccination, 87% of patients developed anti-HBs levels above 10 IU/l. 27.8% and 59.2% of them were weak responders and high responders respectively. 13% of patients were non-responders. After 1-year follow-up, 18.18% of responders had lost their anti-HBs (transient responders). All of them were initially in weak responders group and had lower anti-HBs levels.

CONCLUSION

We found an average percentage of seroconversion after primary HBV vaccination in HD patients. Our study also supported this fact that an antibody titre above 100 IU/l following primary vaccination is necessary to maintain that level of antibody 1 year later.

Genetic diversity of grapevine accessions from Iran, Russia and USA using microsatellite markers

To discover marker information content and differentiation among grapevine accessions from Iran, USA and Russia, nine microsatellite markers were used. A total of 75 alleles were detected, giving a mean of 8.3 alleles per 9 loci. The total number of alleles per locus varied between 6 to 11 and the polymorphism information content ranged from 0.65 to 0.88, indicating that these loci were highly informative. A positive correlation (r = 0.870) was observed between the number of alleles and the level of polymorphism. Two SSRs loci including SSrVrZAG47 and VVMD27 were found to be probably synonymous. Gene diversities were high in all populations with values ranging from 0.709 to 0.784. In all populations, the mean number (averaged over loci) of heterozygous individuals was higher than expected. PCO analysis could not be so clearly differentiated accessions from Iran and Russia. The pattern of clustering of the Vitis vinifera populations was according to their geographic distribution. It is suggested that accessions could possibly be assigned to their regions of origin according to their genotypes.

Posterior sub-tenon triamcinolone for refractory diabetic macular edema: a randomized clinical trial

PURPOSE

To evaluate the effect of posterior sub-tenon triamcinolone acetonide (TA) injection on clinical, angiographic, and optical coherence tomographic (OCT) parameters in refractory diabetic macular edema (DME).

METHODS

In a double-masked placebo-controlled clinical trial, 64 eyes were randomly assigned to two groups. The treatment group (32 eyes) received 40 mg posterior sub-tenon injection of TA and the placebo group (32 eyes) received subconjunctival injection of a placebo. The injections were repeated after 2 months in both groups. Complete ophthalmologic examination, fluorescein angiography, and OCT were performed before intervention and after 4 months. Quantitative measurement of angiographic variables such as the amount of hard exudates (HE), size of foveal avascular zone (FAZ), and leakage severity was performed by computer, using Photoshop software.

RESULTS

Initial best-corrected visual acuity (VA) was 0.93+/-0.39 logMAR in the placebo group and 0.75+/-0.38 logMAR in the treatment group. At 4 months, corrected VA was 0.88+/-0.48 logMAR in the controls versus 0.71+/-0.42 logMAR in the cases. Mean central macular thickness measured by OCT before and 4 months after injection was 392 and 377 microns in the treatment group and 388 and 357 microns in the placebo group, respectively. No statistically significant difference was detected between the two groups. The difference was also not significant in HE, FAZ, and leakage in the angiograms.

CONCLUSIONS

Two injections of posterior sub-tenon TA had no therapeutic effect on refractory DME.

Rhesus monkey placental transgene expression after lentiviral gene transfer into preimplantation embryos

Transgenic mice have provided invaluable information about gene function and regulation. However, because of marked differences between rodents and primates, some areas of human biology such as early embryonic development, aging, and maternal-fetal interactions would be best studied in a nonhuman primate model. Here, we report that gene transfer into rhesus monkey (Macaca mulatta) preimplantation embryos gives rise to transgenic placentas that express a reporter transgene (eGFP). Blastocysts resulting from culture of in vitro fertilized ova were transduced with a self-inactivating lentiviral vector and transferred into recipient females. One twin and one singleton pregnancy were produced from a single stimulation cycle, and one live rhesus monkey was born from each pregnancy. Placentas from all conceptuses showed expression of the transgene as detected by reverse transcription-PCR, ribonuclease protection assay, direct epifluorescence, immunohistochemistry, and Western blot analysis. Integration in somatic tissues of the offspring was not detected. A maternal immune response to the xenogeneic placental antigen was shown by the presence of anti-GFP antibodies in peripheral blood of the recipient females by day 99 of gestation (term = 165 days). These results demonstrate that transgene expression during gestation is compatible with successful pregnancy in nonhuman primates and provides an approach that could be broadly applicable to the development of novel models for primate biomedical research.

Four-color flow cytometric detection of retrovirally expressed red, yellow, green, and cyan fluorescent proteins

Flow cytometric procedures are described to detect a "humanized" version of a new red fluorescent protein (DsRed) from the coral Discosoma sp. in conjunction with various combinations of three Aequorea victoria green fluorescent protein (GFP) variants--EYFP, EGFP, and ECFP. In spite of overlapping emission spectra, the combination of DsRed with EYFP, EGFP, and ECFP generated fluorescence signals that could be electronically compensated in real time using dual-laser excitation at 458 and 568 nm. Resolution of fluorescence signals from DsRed, EYFP, and EGFP was also readily achieved by single-laser excitation at 488 nm. Since many flow cytometers are equipped with an argon-ion laser that can be tuned to 488 nm, the DsRed/EYFP/EGFP combination is expected to have broad utility for facile monitoring of gene transfer and expression in mammalian cells. The dual-laser technique is applicable for use on flow cytometers equipped with tunable multiline argon-ion and krypton-ion lasers, providing the framework for studies requiring simultaneous analysis of four fluorescent gene products within living cells.

Lentiviral vectors for enhanced gene expression in human hematopoietic cells

Accumulated data indicate that current generation lentiviral vectors, which generally utilize an internal human cytomegalovirus (CMV) immediate early region enhancer-promoter to transcribe the gene of interest, are not yet optimized for efficient expression in human hematopoietic stem/progenitor cells (HSPCs). As a first step toward this goal, we constructed self-inactivating derivatives of the HIV-1-based transfer vector pHR' containing the enhanced green fluorescent protein (GFP) gene as reporter and the Woodchuck hepatitis virus posttranscriptional regulatory element (WPRE). GFP expression was driven by a variety of strong viral and cellular promoters, including the murine stem cell virus (MSCV) long terminal repeat (LTR), a Gibbon ape leukemia virus (GALV) LTR, the human elongation factor 1alpha (EF1alpha) promoter, the composite CAG promoter (consisting of the CMV immediate early enhancer and the chicken beta-actin promoter), and the human phosphoglycerate kinase 1 (PGK) promoter. In contrast to results obtained in human embryonic kidney 293T cells and fibrosarcoma HT1080 cells, in which the CMV promoter expressed GFP at the highest levels, significantly higher levels of GFP expression (3- to 5-fold) were achieved with the MSCV LTR, the EF1alpha promoter, and the CAG promoter in the human HSPC line KG1a. Removal of the WPRE indicated that it stimulated GFP expression from all of the vectors in KG1a cells (up to 3-fold), although it only marginally improved the performance of the intron-containing EF1alpha and CAG promoters (<1.5-fold stimulation). The vectors using the MSCV LTR, the GALV LTR, and the PGK promoter were the most efficient at transducing primary human CD34+ cord blood progenitors under the conditions employed. High-level GFP expression in the NOD/SCID xenograft model was demonstrated with the pHR' derivative bearing the MSCV LTR. These new lentiviral vector backbones provide a basis for the rational design of improved delivery vehicles for human HSPC gene transfer applications.

Targeted RNases: a feasibility study for use in HIV gene therapy

A targeted RNase would be ideal for gene therapy of several acquired and inherited disorders. Such an RNase may be engineered to contain a ribonucleolytic domain and a specific target RNA binding domain. To demonstrate the feasibility of this approach, an RNase targeted against human immunodeficiency virus (HIV) RNA--Tev-RNase T1--was designed and tested for its use in HIV-1 gene therapy. A human CD4+ T lymphoid (MT4) cell line and human peripheral blood lymphocytes (PBLs) were transduced with retroviral vectors lacking or expressing the tevT1 gene. Expression of enzymatically functional Tev-RNase T1 protein and its lack of toxicity was demonstrated in stable MT4 transductants. Compared with control cells lacking this protein, both transduced MT4 cells and PBLs expressing Tev-RNase T1 delayed HIV-1 replication. Tev-RNase T1 was shown to act after integration, since HIV-1 proviral DNA could be detected, but the amount of HIV-1 RNA produced in MT4 cells and PBLs was significantly decreased. This study demonstrates the feasibility of a targeted RNase strategy for therapeutic use.

Inhibition of HIV-1 replication by retroviral vectors expressing monomeric and multimeric hammerhead ribozymes

Retroviral vectors were engineered to express monomeric and multimeric hammerhead ribozymes targeting one and nine highly conserved sites within the HIV-1 envelope (Env) coding region. In vitro, both the monomeric and multimeric ribozymes were shown to be active and cleave the target RNA containing the cleavage sites. A human CD4+ T lymphocyte-derived MT4 cell line was stably transduced with retroviral vectors expressing these ribozymes. Ribozyme expression in stably transduced cells was confirmed by Northern blot analysis and reverse-transcription polymerase chain reaction (RT-PCR). As compared with the control cells lacking any ribozyme, HIV-1 replication was delayed in monomeric RzEnv-expressing cells. Virus replication was almost completely inhibited in multimeric RzEnv1-9-expressing cells as no viral RNA or protein could be detected in these cells and in their culture supernatants for up to 60 days after infection. The genomic DNA from RzEnv1-9-expressing cells was shown to contain HIV-1 proviral DNA sequences at days 3 and 60 after HIV infection. HIV-1 used in the challenge experiments was found to contain fully reverse transcribed '-' strand DNA which should have been able to infect complete proviral DNA synthesis and integrate within the cellular genome without being affected by pre-existing ribozymes. Therefore, the proviral DNA present at day 3 after infection may have originated from infection by such DNA-containing virus particles. The results obtained with the retroviral vector expressing RzEnv1-9 are very encouraging and we envisage its future use in anti-HIV-1 gene therapy.

A rapid and efficient system for screening HIV-1 Pol mRNA-specific ribozymes

Hammerhead ribozymes are potentially important tools for suppressing intracellular expression of unwanted RNAs. However, the reports that exist on their activity against different targets have described mixed success. As an initial step towards developing a rapid and effective system for in vivo testing of ribozymes, two human immunodeficiency virus type-1 (HIV-1) polymerase (Pol) mRNA-specific ribozymes, RzPro directed against the protease (Pro) coding region and RzRT directed against the reverse transcriptase (RT) coding region, were designed and tested in Escherichia coli. Both ribozymes displayed similar efficiencies in cleaving their target RNAs in vitro. RNA polymerase chain reaction was adapted to demonstrate the in vivo cleavage of RzPro and RzRT target sites. The resultant drop in HIV-1 RT activity was measured as well. The degree of suppression of RT activity was more apparent in vivo in cells expressing RzRT. The RT activity in cells expressing RzRT was shown to decrease by up to 96%. This system will be useful for rapid screening of (i) other ribozyme target sites within the Pol mRNA so that multitargeted ribozymes could be designed for use in anti-HIV-1 gene therapy, (ii) ribozymes with improved stability and catalytic activity, and (iii) cofactors, if any that could enhance ribozyme activity in vivo.

Comparative analysis of five highly conserved target sites within the HIV-1 RNA for their susceptibility to hammerhead ribozyme-mediated cleavage in vitro and in vivo

Moloney murine leukemia virus (MMLV)-derived pUCMoTiN-based retroviral vectors were engineered to allow constitutive and Tat (trans-activator of transcription)-inducible expression of five hammerhead ribozymes targeted against highly conserved sequences within the group antigen (Gag), protease (Pro), reverse transcriptase (RT), tat, and envelope (Env) coding regions of human immunodeficiency virus type-1 (HIV-1) RNA. Amphotropic retroviral vector particles were used to infect a human CD4+ lymphocyte-derived MT4 cell line. The pool of stable MT4 transductants expressing these ribozymes were each tested for their susceptibility to HIV-1 infection. RzTat conferred no protection to MT4 cells. RZGag and RzRT completely inhibited virus multiplication for 6 days. RzPro and RzEnv conferred the best protection, as they completely inhibited virus production for 12 and 15 days, respectively. No correlation was found between the degree of HIV-1 resistance conferred and the ability of these ribozymes to cleave their target RNA in vitro. From RzPro-expressing HIV-1-infected cells following virus escape, RzPro and target RNA sequences were amplified and checked for cleavage in vitro. The ribozyme expressed in these cells was shown to cleave the corresponding target RNA. Thus, a mutation in the ribozyme or target RNA does not seem to be the mechanism underlying virus escape.

Inhibition of HIV-1 multiplication in a human CD4+ lymphocytic cell line expressing antisense and sense RNA molecules containing HIV-1 packaging signal and Rev response element(s)

Moloney murine leukemia virua (MoMuLV)-derived retroviral vectors were engineered to express human immunodeficiency virus type 1 (HIV-1) packaging (psi) signal and Rev response element (RRE) sequences in either sense or antisense orientation. The RRE sequences were expressed under the control of the herpes simplex virus (HSV) thymidine kinase (tk) promoter fused to the HIV-1 trans-activation-responsive (TAR) element, while the psi signal sequences were expressed under control of the HSV tk promoter. Both RRE and psi signal sequences were expressed as part of the 3' untranslated region of the neomycin phosphotransferase (neo) mRNA. The constructs were used to transfect/infect packaging cell lines and the retroviral vector particles released were used to infect a human CD4+ lymphocyte-derived MT4 cell line. The stable MT4 transformants, harboring proviral vector DNA expressing one to two copies of HIV-1 RRE and psi signal in either antisense or sense orientation, were each tested for their susceptibility to HIV-1 infection. Compared to the results obtained with the control cells lacking any of the test DNA sequences, the rate of HIV-1 production remained unaltered in RRE1+ (sense RNA containing a single copy of RRE) RNA-containing cells, whereas it was delayed in cells expressing both RRE2+ (sense RNA containing two copies of RRE) and RRE1- (antisense RNA containing a single copy of RRE) RNA-expressing cells. In cells expressing HIV-1 psi signal, HIV-1 production remained unaltered in psi + RNA-expressing cells, whereas it was delayed by up to 30 days in psi - RNA-expressing cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The development and testing of retroviral vectors expressing trans-dominant mutants of HIV-1 proteins to confer anti-HIV-1 resistance

Trans-dominant mutants of human immunodeficiency virus type 1 (HIV-1) Tat and Rev are attractive candidates for use in gene therapy in the treatment of HIV-1 infections because both are essential for viral replication. Retroviral vectors were constructed to allow either Tat-inducible or Tat- and Rev-inducible expression of trans-dominant mutants of Tat and Rev. These vectors were used to infect a human CD4+ lymphocyte-derived cell line, MT4. To determine the efficacy of various Tat and Rev mutants in inhibiting HIV-1 multiplication, MT4 cells containing mutant-expressing constructs were infected with HIV-1, and the amount of HIV-1 released in the culture medium was measured for up to 30 days. A high level of resistance was observed in cells expressing the double tat/rev mutant in a Tat-inducible manner.