A comprehensive review on the role of T cell subsets and CAR-T cell therapy in Aspergillus fumigatus infection

Understanding the immune response to Aspergillus fumigatus, a common cause of invasive fungal infections (IFIs) in immunocompromised individuals, is critical for developing effective treatments. Tcells play a critical role in the immune response to A. fumigatus, with different subsets having distinct functions. Th1 cells are important for controlling fungal growth, while Th2 cells can exacerbate infection. Th17 cells promote the clearance of fungi indirectly by stimulating the production of various antimicrobial peptides from epithelial cells and directly by recruiting and activating neutrophils. Regulatory T cells have varied functions in A.fumigatus infection. They expand after exposure to A. fumigatus conidia and prevent organ injury and fungal sepsis by downregulating inflammation and inhibiting neutrophils or suppressing Th17 cells. Regulatory T cells also block Th2 cells to stop aspergillosis allergies. Immunotherapy with CAR T cells is a promising treatment for fungal infections, including A. fumigatus infections, especially in immunocompromised individuals. However, further research is needed to fully understand the mechanisms underlying the immune response to A. fumigatus and to develop effective immunotherapies with CAR-T cells for this infection. This literature review explores the role of Tcell subsets in A.fumigatus infection, and the effects of CAR-T cell therapy on this fungal infection.

The effect of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis: A double-blind, placebo, controlled randomized clinical trial

Propolis has gained popularity in recent years because of its beneficial properties, which make it a possible preventative and therapeutic agent as well as a valuable food and cosmetic ingredient. The objective of this study was to evaluate the effects of propolis supplementation on cardiovascular risk factors in women with rheumatoid arthritis. This randomized, double-blind, placebo-controlled clinical trial was performed among 48 patients diagnosed with rheumatoid arthritis. Subjects were randomly assigned to placebo and intervention groups, supplemented with 1000 mg/day of propolis for 12 weeks. Cardiovascular risk factors including, high-sensitivity C-reactive protein (hs-CRP), monocyte chemoattractant protein (MCP-1), Nitric oxide, blood pressure, and lipid profile were assessed pre-and post-intervention. The atherogenic index of plasma value, as well as total cholesterol/high-density lipoprotein cholesterol (HDL-C), triglyceride/HDL-C, and non-HDL-C/HDL-C ratios, were significantly reduced in the intervention group, compared with the placebo group post-intervention (p < 0.05). Moreover, there was a significant reduction in the serum level of hs-CRP in the intervention group when compared with the placebo group (p = 0.001). Furthermore, propolis supplementation could marginally reduce MCP-1 (p = 0.051). These data indicate that propolis supplementation may be a promising treatment strategy for cardiovascular complications among rheumatoid arthritis patients.

Cobalt ferrite nanoparticle for the elimination of CD133+CD44+ and CD44+CD24-, in breast and skin cancer stem cells, using non-ionizing treatments

Background

Cancer stem cells (CSCs) are the most challenging issue in cancer treatment, because of their high resistance mechanisms, that can cause tumor recurrence after common cancer treatments such as drug and radiation based therapies, and the insufficient efficiency of common treatments in CSCs removal and the recurrence of tumors after these treatments, it is essential to consider other methods, including non-ionizing treatments likes light-based treatments and magnetic hyperthermia (MHT).

Method and material

After synthesis, characterization and investigation, the toxicity of novel on A375 and MAD-MB-231 cell lines, magnetic hyperthermia and light-based treatments were applied. MTT assay and flow cytometry was employed to determine cell survival. the influence of combination therapy on CD44 + CD24-and CD133 + CD44+ cell population, Comparison and evaluation of combination treatments was done respectively using Combination Indices (CIs).

Result

The final nanoparticle has a high efficiency in producing hydroxyl radicals and generating heat in MHT. According to CIs, we can conclude that combined using of light-based treatment and MHT in the presence of final synthesized nanoparticle have synergistic effect and a high ability to reduce the population of stem cells in both cell lines compared to single treatments.

Conclusion

In this study a novel multi-functional nanoplatform acted well in dual and triple combined treatments, and showed a good performance in the eradication of CSCs, in A375 and MAD-MB-231 cell lines.

Intermittent fasting: A promising dietary intervention for autoimmune diseases

Intermittent fasting, which includes periods of fasting and nutrition, has been considered a dietary approach for weight loss and metabolic health improvement. However, its potential benefits in autoimmune diseases have not been widely studied. This study aims to review the existing studies on the role and effects of intermittent fasting on autoimmune diseases. A comprehensive search was conducted on electronic databases such as PubMed, Scopus, Embase, and Web of Science, and relevant studies were included based on inclusion criteria. Studies show that intermittent fasting may have beneficial effects on various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and systemic lupus erythematosus, by reducing inflammatory markers, modulating the immune system, altering and improving gut microbiota, and enhancing cellular repair mechanisms through autophagy. However, evidence regarding the effects of intermittent fasting on other autoimmune diseases such as multiple sclerosis, systemic lupus erythematosus, thyroid diseases, and psoriasis is limited and inconclusive. Nevertheless, further research is needed to determine optimal intermittent fasting guidelines and its long-term effects on autoimmune diseases. Overall, this literature review proves intermittent fasting may be a promising dietary intervention for managing autoimmune diseases.

Animal and plant-based proteins have different postprandial effects on energy expenditure, glycemia, insulinemia, and lipemia: A review of controlled clinical trials

Dietary proteins have been shown to stimulate thermogenesis, increase satiety, and improve insulin sensitivity in the short and long term. Animal-based proteins (AP) and plant-based proteins (PP) have different amino acid profiles, bioavailability, and digestibility, so it seems to have various short- and long-term effects on metabolic responses. This review aimed to compare the findings of controlled clinical trials on postprandial effects of dietary Aps versus PPs on energy expenditure (EE), lipemia, glycemia, and insulinemia. Data are inconclusive regarding the postprandial effects of APs and PPs. However, there is some evidence indicating that APs increase postprandial EE, DIT, and SO more than PPs. With lipemia and glycemia, most studies showed that APs reduce or delay postprandial glycemia and lipemia and increase insulinemia more than PPs. The difference in amino acid composition, digestion and absorption rate, and gastric emptying rate between APs and PPs explains this difference.

Cladosporium tenuissimum-induced sinusitis in a woman with immune-deficiency disorder

Fungal sinusitis is a widespread infection that affects both healthy and immunocompromised individuals. Reports of sinus fungal infections have increased due to recent advances in diagnosis. Furthermore, susceptible and immune-compromised patients play an important role in increasing the number of reported cases. Infections with lesser-known fungi have been reported infrequently around the world. This paper describes a Cladosporium tenuissimum infection caused by chronic fungal sinusitis in a woman who had traveled to several countries. We used morphological and molecular methods to confirm the infection. The infection is most likely caused by the use of sulfasalazine, which is related to the patient's rheumatism. Sulfasalazine inhibits neutrophilic chemoattractant lipid synthesis in neutrophils, which play a key role in antifungal immunity. The patient is also undergoing root canal therapy and has several upper jaw implants, which may have contributed to the development of sinusitis.

The effects of Chlorella vulgaris on cardiovascular risk factors: A comprehensive review on putative molecular mechanisms

High incidence rate of cardiovascular disease (CVD) make this condition as an important public health concern. The use of natural products in treating this chronic condition has increased in recent years one of which is the single-celled green alga Chlorella. Chlorella vulgaris (CV) has been studied for its potential benefits to human health due to its biological and pharmacological features. CV contains a variety of macro and micronutrients, including proteins, omega-3, polysaccharides, vitamins, and minerals. Some studies have indicated that taking CV as a dietary supplement can help reduce inflammation and oxidative stress. In some studies, cardiovascular risk factors that are based on hematological indices did not show these benefits, and no molecular mechanisms have been identified. This comprehensive review summarized the research on the cardio-protective benefits of chlorella supplementation and the underlying molecular processes.

A review of PD-1/PD-L1 siRNA delivery systems in immune T cells and cancer cells

OBJECTIVES

Programmed cell death 1 (PD-1) is a member of the CD28/CTLA-4 family of inhibitory immunological checkpoint receptors that's also widely produced by exhausted T lymphocytes in an immunosuppressive tumor microenvironment. PD-1 binds to programmed death ligand (PD-L1) and suppresses anti-cancer activity of T lymphocytes. We examined the current literature on how siRNA delivery systems can be used to target PD-1 and PD-L1, as well as the anti-cancer mechanisms and challenges associated with siRNA molecules. We look at studies that use program death 1 siRNA or program death 1 ligand siRNA to treat cancer. Several databases have been used for this purpose, including NCBI, Scopus, and Google Scholar.

KEY FINDINGS

This study looked at several methods for delivering siRNA to immune cells and cancer cells. According to these findings, suppressing PD-1 in T cells increases T lymphocyte activity. PD-L1 suppression in DCs improves antigen presentation and co-stimulatory signals on their surface, resulting in T cell activation. Chemotherapy resistance and cancer cell suppression of T cells are reduced when PD-L1/2 is suppressed in cancer cells.

CONCLUSION

The findings of this study indicated that several strategies for siRNA transfection to immune and cancer cells have been evaluated in recent decades, some of which effectively transfect siRNA to target cells, and defined PD-1 siRNA as a promising strategy for cancer treatment.

CD73 downregulation by EGFR-targeted liposomal CD73 siRNA potentiates antitumor effect of liposomal doxorubicin in 4T1 tumor-bearing mice

Blocking CD73 ectonucleotidase has been proposed as a potential therapeutic approach for cancer treatment. The present study aimed to investigate the antitumor effect of a novel EGFR-Targeted liposomal CD73 siRNA formulation in combination therapy with liposomal doxorubicin in the 4T1 mouse model. CD73 siRNA was encapsulated into nanoliposomes by the ethanol injection method. After preparation, characterization, morphology, and stability evaluation of formulations, the toxicity was measured by MTT assay. Uptake assay and efficiency of the liposomal formulations were investigated on the 4T1 cell line. The liposomal formulation containing CD73 siRNA was targeted with GE11 peptide for in vivo evaluations. Following biodistribution analysis, the antitumor activity of prepared formulations in combination with liposomal doxorubicin was studied in mice bearing 4T1 metastatic breast cancer cells. Finally, the induction of immune response of formulations in concomitant treatment with liposomal doxorubicin was evaluated in the tumor microenvironment of a mouse model of breast cancer. The size of prepared liposomal formulations at N/P = 16 for the liposomal CD73 siRNA and GE11-liposomal CD73 siRNA groups were 89 nm ± 4.4 and 95 nm ± 6.6, respectively. The nanoparticle's PDI was less than 0.3 and their surface charge was below 10 mV. The results demonstrated that N/P = 16 yielded the best encapsulation efficiency which was 94% ± 3.3. AFM results showed that the liposomes were spherical in shape and were less than 100 nm in size. The results of the MTT assay showed significant toxicity of the liposomes containing CD73 siRNA during the 48-h cell culture. Real-time PCR and flow cytometry results showed that liposomes containing CD73 siRNA could effectively downregulate CD73 expression. Liposomal formulations were able to significantly downregulate CD73 gene expression, in vivo. However, CD73 downregulation efficiency was significantly higher for the targeted form compared to the non-targeted formulation (P value < 0.01). The combination showed maximum tumor growth delay with remarkable survival improvement compared to the control group. Studying the immune responses in the treatment groups which received doxorubicin, showed decreased number of lymphocytes in the tumor environment. However, this decrease was lower in the combination therapy group. Finally, our results clearly showed that CD73 downregulation increases the activity of CD8⁺ lymphocytes (IFN-ℽ production) and also significantly decreases the Foxp3 in the CD25⁺ lymphocytes compared to the control group. GE11-Lipo CD73 siRNA formulation can efficiently knockdown CD73 ectonucleotidase. Also, the efficacy of liposomal doxorubicin is significantly enhanced via the downregulation of CD73 ectonucleotidase.

Enhanced antitumor immune response in melanoma tumor model by anti-PD-1 small interference RNA encapsulated in nanoliposomes

Programmed cell death protein-1 (PD-1), as an immune checkpoint molecule, attenuates T-cell activity and induces T-cell exhaustion. Although siRNA has a great potential in cancer immunotherapy, its delivery to target cells is the main limitation of using siRNA. This study aimed to prepare a liposomal formulation as a siRNA carrier to silence PD-1 expression in T cells and investigate it's in vivo antitumor efficacy. The liposomal siRNA was prepared and characterized by size, zeta potential, and biodistribution. Following that, the uptake assay and mRNA silencing were evaluated in vitro at mRNA and protein levels. siRNA-PD-1 (siPD-1)-loaded liposome nanoparticles were injected into B16F0 tumor-bearing mice to evaluate tumor growth, tumor-infiltrating lymphocytes, and survival rate. Liposomal siPD-1 efficiently silenced PD-1 mRNA expression in T cells (P < 0.0001), and siPD-1-loaded liposomal nanoparticles enhanced the infiltration of T-helper 1 (Th 1) and cytotoxic T lymphocytes into the tumor tissue (P < 0.0001). Liposome-PD-1 siRNA monotherapy and PD-1 siRNA-Doxil (liposomal doxorubicin) combination therapy improved the survival significantly, compared to the control treatment (P < 0.001). Overall, these findings suggest that immunotherapy with siPD-1-loaded liposomes by enhancing T-cell-mediated antitumor immune responses could be considered as a promising strategy for the treatment of melanoma cancer.

Pegylated liposomal encapsulation improves the antitumor efficacy of combretastatin A4 in murine 4T1 triple-negative breast cancer model

Combretastatin A4 (CA4), a vascular disrupting agent has been recently proposed as an anticancer agent. However, its low water solubility and low bioavailability limited its clinical efficacy. Overcomingthis issue requires developing new delivery strategies to enhance its anticancer effects. Here, we prepared various PEGylated liposomal formulations containing CA4 composed of different molar ratios of HSPC/DSPE-mPEG₂₀₀₀/Cholesterol/CA4 (F1: 80:5:10:5; F2: 75:5:15:5; F3: 70:5:20:5; F4: 60:5:30:5 and F5: 50:5:40:5) by the thin-film hydration method plus sonication and extrusion. All formulations had a particle diameter of 100-150 nm, a monomodal distribution with low polydispersity index and a negative zeta potential. Among the formulations only F1, F2, and F3 showed a high CA4 encapsulation efficiency; so their anticancer effects on triple-negative breast cancer (TNBC) were investigated in vitro and in vivo. The release study showed that F3 liposomes had significantly lower CA4 release compared to the F1 and F2 liposomes in different pH of 5.5, 6.5, and 7.4. We found that, CA4-loaded liposomes effectively inhibited both proliferation and migration of 4T1 and MDA-MB-231 TNBC cell lines by inducing cell cycle arrest at the G2/M phase and decreasing MMP-2 and MMP-9 expression and activity. In vivo studies revealed that F3 liposomes were highly accumulated at the tumor site and more effectively delayed tumor growth andprolonged the overall survival than other groups in 4T1 breast tumor-bearing mice. Taken together, encapsulation of CA4 in PEGylated F3 liposomes enhances its anti-tumor activity and may be serve as a promising approach for TNBC treatment and merits further investigation.

Biological and pharmacological effects and nutritional impact of phytosterols: A comprehensive review

Phytosterols (PSs), classified into plant sterols and stanols, are bioactive compounds found in foods of plant origin. PSs have been proposed to exert a wide number of pharmacological properties, including the potential to reduce total and low-density lipoprotein (LDL) cholesterol levels and thereby decreasing the risk of cardiovascular diseases. Other health-promoting effects of PSs include anti-obesity, anti-diabetic, anti-microbial, anti-inflammatory, and immunomodulatory effects. Also, anticancer effects have been strongly suggested, as phytosterol-rich diets may reduce the risk of cancer by 20%. The aim of this review is to provide a general overview of the available evidence regarding the beneficial physiological and pharmacological activities of PSs, with special emphasis on their therapeutic potential for human health and safety. Also, we will explore the factors that influence the physiologic response to PSs.

Use of antioxidant nanoparticles to reduce oxidative stress in blood storage

Oxidative damage by free radicals has a negative effect on blood quality during storage. Antioxidant nanoparticles can prevent oxidative stress. We use SOD-CAT-Alb-PEG-PLGA- nanoparticles to reduce the effects of oxidative stress in blood storage. Electrospray was employed to prepare nanoparticles. Nanoparticles entered the test bags and were kept for 35 days from the time of donation under standard conditions. On target days, experiments were performed on the samples taken. The examination included blood smear, red blood cells count, hemoglobin, hematocrit, K, Fe, glutathione peroxidase, glutathion reductase, glucose-6-phosphate dehydrogenase, prooxidant-antioxidant balance, malondialdehyde, and flow cytometric assay for phosphatidylserine. The repeated measures analysis was performed on samples every week. Morphological changes were less in the test group compared to the control. The quantitative hemolysis profile test showed significant changes in the test and control groups (p < 0.05) in consecutive weeks except for K and Fe. Oxidative stress parameters too showed a significant change during the target days of the examination (p < 0.05). Also, the phosphatidylserine expression was increased in control groups more than test in consecutive weeks (p < 0.05). It seems that the use of antioxidant nanoparticles improves the quality of stored red blood cells and can prevent posttransfusion complications and blood loss by reducing oxidative stress.

A review on liposome-based therapeutic approaches against malignant melanoma

Melanoma is a highly aggressive form of skin cancer with a very poor prognosis and excessive resistance to current conventional treatments. Recently, the application of the liposomal delivery system in the management of skin melanoma has been widely investigated. Liposomal nanocarriers are biocompatible and less toxic to host cells, enabling the efficient and safe delivery of different therapeutic agents into the tumor site and further promoting their antitumor activities. Therefore, the liposomal delivery system effectively increases the success of current melanoma therapies and overcomes resistance. In this review, we present an overview of liposome-based targeted drug delivery methods and highlight recent advances towards the development of liposome-based carriers for therapeutic genes. We also discuss the new insights regarding the efficacy and clinical significance of combinatorial treatment of liposomal formulations with immunotherapy and conventional therapies in melanoma patients for a better understanding and successfully managing cancer.

Exercise and crocin prevent adolescent-stress induced impairment of spatial navigation and dendritic retraction in the hippocampal CA3 area in adult male rats

Adolescent chronic stress has been shown to induce functional, biochemical and morphological modifications of the hippocampus, leading to stress-related disorders in adulthood. The present study investigated the effects of exercise, crocin and their combination on spatial learning and memory impairment and dendritic retraction of the CA3 pyramidal neurons induced by chronic adolescent stress in adult male rats. Rats were exposed to restraint stress 2 h/day for 10 days during postnatal days (PNDs) 30-40. Following this period, separate groups of animals were treated with crocin (25 and 50 mg/kg), exposed to running wheel, and or received the combined treatment during PNDs 41-55. Following the interventions, plasma levels of corticosterone, spatial learning and memory, apical dendritic length of CA3 pyramidal neurons and BDNF levels in the CA3 area were assessed. Findings showed that adolescent stress significantly increased corticosterone levels and caused a tendency to reduce CA3 BDNF levels. Adolescent stress also impaired spatial learning and memory, and retracted apical dendritic length of CA3 pyramidal neurons. Crocin, voluntary exercise, and their combination recovered stress-induced spatial learning and impairment and CA3 pyramidal neurons dendritic length retraction. All treatments also reduced significantly corticosterone levels and enhanced CA3 BDNF levels in the stress groups. Finally, these treatments even increased apical dendritic length of CA3 pyramidal neurons in the non-stress groups. These findings indicate that detrimental effects of adolescent stress on cognitive function and hippocampal morphology in adulthood could be restored by early interventions with physical activity and crocin treatment during adolescent period.

Co-administration of Aluminum Sulfate and Propolis Regulates Matrix Metalloproteinases-2/9 Expression and Improves the Uterine Leiomyoma in Adult Rat Model

The aim of this study was to evaluate the effects of aluminum sulfate (alum) with propolis (PR) on uterine leiomyoma (UL) in rat model. One hundred and four female Wistar rats (180-200 g) were allocated into two main groups of control (Co, n = 8) and experiment (UL model [estradiol benzoate 200 μg/kg/IM twice/week/8 weeks] with/without treatment) defined in 13 subgroups with/without treatment with coil oil (UL + COi), PR (100 or 200 mg/kg) as UL + PR100 or 200, alum (35, 75 or 150 mg/Kg) as UL + AL 35, 75, or 150, and PR (100 mg/kg or 200) with alum (35, 75, or 150 mg/Kg) as UL + PR100 or 200 + AL35, 75, or 150. Subgroups received doses of therapeutics for 14 days (IP). In the end, rats were sacrificed, and the uteri were isolated for molecular and histopathological investigations. The myometrium thickness, collagen contents, and gene expression of MMP-2 and 9 increased significantly in experimental groups with/without treatment (P ˂ 0.05). PR administration (100 and 200 mg/kg) alone or with alum (35 and 75 mg/kg) significantly decreased myometrium collagen contents and the gene expression and protein concentration of MMP-2 and 9 compared with UL and UL + Coi subgroups (P ˂ 0.05). Alum (75 mg/kg) with PR (200 mg/kg) could improve UL features and reduce MMP-2 and 9 gene expression.

MicroRNAs as the Important Regulators of T Helper 17 Cells: A Narrative Review

T helper (Th)-17 cells are a distinct and important subset of Th cells and their functions are due to the ability of production and secretion of key cytokines in the immune system such as interleukin (IL)-17, IL-22, IL-21, and tumor necrosis factor-α (TNF-α). According to these cytokines, these cells have vital roles in the pathogenesis of the disease such as rheumatoid arthritis (RA) and osteoarthritis (OA). Nowadays, microRNAs (miRNAs) are defined as essential regulators of cell function by targeting transcription factors and other elements that act in cells to control gene expression. The purpose of this study was to detect and investigate articles evaluating the function of miRNA in Th-17 cell performance. The language was restricted to English and the search was done in PubMed, Web of Science and Embase. In this review, we first explain the role of effective factors in the function of Th17 lymphocytes, and then, we summarize the performance of several miRNAs involved in the activation and appropriate functions of Th17 cells in the immune system.

Resveratrol: Mechanistic and therapeutic perspectives in pulmonary arterial hypertension

Resveratrol, trans 3,5,4'-trihydroxystilbene, is a stilbenoid polyphenol with a wide range of properties including antioxidant, neuroprotective, cardioprotective, anti-inflammatory and anticancer activities. It is found in the skins of grape (50-100 μg/mL), red wine, peanuts, bilberries, blueberries and cranberries. The most important effects of resveratrol have been found in cardiovascular disease, with pulmonary arterial hypertension (PAH) being a major severe and progressive component. Many factors are involved in the pathogenesis of PAH, including enzymes, transcription factors, proteins, chemokines, cytokines, hypoxia, oxidative stress and others. Resveratrol treats PAH through its actions on various signaling pathways. These signaling pathways are mainly suppressed SphK1-mediated NF-κB activation, BMP/SMAD signaling pathway, miR-638 and NR4A3/cyclin D1 pathway, SIRT1 pathway, Nrf-2, HIF-1 α expression, MAPK/ERK1 and PI3K/AKT pathways, and RhoA-ROCK signaling pathway. Resveratrol efficiently inhibits the proliferation of pulmonary arterial smooth muscle cells and right ventricular remodeling, which are underlying processes leading to enhanced PAH. While supportive evidence from randomized controlled trials is yet to be available, current in vitro and in vivo studies seem to be convincing and suggest a therapeutic promise for the use of resveratrol in PAH.

Predicting Aggressive Behavior in Nonfunctional Pancreatic Neuroendocrine Tumors With Emphasis on Tumor Size Significance and Survival Trends: A Population-Based Analysis of 1787 Patients

BACKGROUND

Nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) are rare tumors with continued controversies in management. This study aims to identify demographic and clinicopathologic characteristics associated with aggressive behavior and survival.

METHODS

The Surveillance, Epidemiology, and End Results database was used to identify patients with NF-PNETs from 1988 to 2012. Multivariate regression analysis and Cox proportional hazards modeling were used to assess the impact of patient, tumor, and treatment characteristics on tumor behavior and overall survival.

RESULTS

In 1787 patients identified, size was a major determinant of aggressive behavior. The probability of aggressiveness increased 100% for tumor size ≥2 cm. For tumors ≥2 cm, every 1-cm increase in size was associated with an increase in probability of aggressive behavior by 11.3%. Patient age, tumor grade, and surgical resection were independent predictors of survival. Surgical resection was associated with improved survival but not grade I or II tumors with size <2 cm.

DISCUSSION

Patient age, tumor size, and grade should be in the decision-making process around the surgical management of NF-PNETs. For tumors ≤2 cm with histologic grades of I or II, the probability of aggressive behavior is low, and surgical resection does not appear to afford survival benefit. Therefore, close observation could be justified.

Factors associated with preventive behaviours of COVID-19 among hospital staff in Iran in 2020: an application of the Protection Motivation Theory

This study was conducted to predict the preventive behaviours of healthcare workers (HCWs) towards COVID-19 based on the Protection Motivation Theory (PMT). This cross-sectional and analytical study was conducted on 761 HCWs in Hamadan, Iran, using multi-stage random sampling. The preventive behaviours against COVID-19 among HCWs were assessed at a relatively desirable level. Based on the PMT, threat and coping appraisal were predictors of protection motivation to conduct COVID-19 preventive behaviours (P<0.001). The intention was also predictive of COVID-19 preventive behaviours (P<0.001). Consideration of personnel's self-efficacy and their knowledge regarding the effectiveness of protective behaviours in designing staff training programmes are recommended.

Evaluating the mechanism underlying antitumor effect of interleukin 27 on B cells of chronic lymphocytic leukemia patients

Chronic lymphocyte leukemia (CLL) is a B-cell malignancy resisted to apoptosis. Recently, some studies indicated that cytokines such as interleukin 27 (IL-27) can reduce B-cell proliferation. The aim of this study is to evaluate the mechanism underlying the proapoptotic effect of IL-27 on B cells of patients with CLL in comparison with B cells of normal subjects. The effect of IL-27 on the antitumor activity of natural killer (NK) and T cells was also evaluated. Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with CLL and 15 normal subjects. B cells and PBMCs were cocultured with IL-27 and B cells apoptosis to evaluate proliferation. Both messenger RNA and protein expression of IL-27 and IL-27 receptor were determined using flow cytometry and real-time polymerase chain reaction analysis. To evaluate the apoptotic effect of IL-27 on B cells of patients with CLL, Annexin V-FITC and 7-AAD (BioLegend) fluorescent dyes were used. In addition, the IL-27 effect on activation of T cell and NK cell was determined by determining CD96 molecule expression. IL-27 and IL-27 receptor expression in patients with CLL was significantly lower than that of normal subjects (p < .05). IL-27 enhanced apoptosis of B cells in patients with CLL (p < .05) but this effect was not significantly observed in B cells of normal subjects (p > .05). Consequently, IL-27 reduced the proliferation of B cells and enhanced NK cell activity (p < .05). IL-27, through inducing apoptosis, can exert an inhibitory effect on cancer B cells of CLL patients with minimal effect on normal B cells.

Therapeutic Effects of Spirulina platensis Against Adolescent Stress-Induced Oxidative Stress, Brain-Derived Neurotrophic Factor Alterations and Morphological Remodeling in the Amygdala of Adult Female Rats

Objective

The amygdala structural and functional abnormalities have been implicated in numerous neuropsychiatric and neurodevelopmental disorders. Given the important role of the amygdala in stress responses and the susceptibility of the females to adolescent stress, the present study investigated the beneficial effects of Spirulina platensis microalgae (SP) as a neuroprotective supplement against adolescent stress-induced oxidative stress, brain-derived neurotrophic factor (BDNF) alterations, molecular and morphological remodeling in the basolateral amygdala (BLA) of adult female rats.

Methods

During the adolescent period (PNDs 30–40) rats were subjected to restraint stress (2 h/day for 10 days). Then, the animals were subjected to 15 days treatment (PNDs 41–55) with SP (200 mg/kg/day) followed by biochemical (BDNF and stress oxidative markers), molecular (BDNF and its receptor tropomyosin receptor kinase B [TrkB] mRNA expression), and morphological (dendritic length and spines) assessments in the BLA.

Results

The study revealed that adolescent stress decreased BDNF levels and reduced apical dendritic length and branch points of pyramidal neurons in the BLA. In addition, chronic stress significantly increased oxidative stress parameters and decreased BDNF and TrkB mRNA expression in the BLA. Treatment with SP alleviated both biochemical, molecular, and neuroanatomical deficits that induced by adolescent stress.

Conclusion

Our findings provide important evidence that SP as a non-pharmacological intervention during adolescent period can protect against chronic stress-induced neuroanatomical biochemical, and molecular deficits in adulthood, and thus, reduce stress-related disorders.

Evaluation of Interleukin 25 and Interleukin 25 Receptor Expression in Peripheral Blood Mononuclear Cells of Breast Cancer Patients and Normal Subjects

[Figure: see text] Interleukin 25 (IL-25) is a ligand for IL-25 receptor (IL-25R) with apoptotic effect on breast cancer epithelial cells that are produced by peripheral blood mononuclear cells (PBMCs). In this study, we aimed to evaluate IL-25/IL-25R mRNA expression in PBMCs, and also investigate correlation of IL-25/IL-25R with tumor stages/grades in patients with breast cancer. PBMCs and serum were isolated from 30 patients with breast cancer and 18 normal subjects. ELISA test was conducted for IL-25 cytokine. Total RNA was isolated from 2 × 10⁶ PBMCs and reverse transcribed to cDNA. Quantitative PCRs were performed for IL-25, IL-25R, and GAPDH genes. IL-25 mRNA expression in PBMCs of breast cancer patients (malignant and benign) was significantly lower than that in normal subjects, Also IL-25 expression in breast cancer patients with malignant tumor was significantly lower than that in nonmalignant patients. IL-25R expression in malignant patients was significantly higher than that of benign and normal subjects (P < 0.05). IL-25 in serum of normal subjects was higher than that of benign and malignant patients. There was a direct association between IL-25R expression and tumor grade/stage of cancer. In conclusion, IL-25 seems as a potential prognostic factor in the serum of breast cancer patients and reduction of IL-25 is associated with a higher grade/stage of cancer.

Protective Effects of Spirulina platensis, Voluntary Exercise and Environmental Interventions Against Adolescent Stress-Induced Anxiety and Depressive-Like Symptoms, Oxidative Stress and Alterations of BDNF and 5HT-3 Receptors of the Prefrontal Cortex in Female Rats

BACKGROUND AND PURPOSE

Ample evidence indicates that chronic adolescence stress is associated with an increased risk of developing neuropsychiatric disorders in adulthood. Given the importance of the effective therapeutic ways to overcome adolescent stress-related deficits, the present study investigated the effects of Spirulina platensis (SP), environmental enrichment (EE), and voluntary exercise (EX) and their combination on anxiety or depression-like behaviors, oxidative stress, and alterations of BDNF and 5HT-3 receptors in the prefrontal cortex (PFC) induced by adolescent stress in adult female rats.

METHODS

During the adolescent period (PNDs30-40), rats were subjected to restraint stress. Then, the animals were subjected to SP treatment (200 mg/kg/day), EX, EE, and the combined treatments (SP+EX, and SP+EE) for 15 days between PNDs41-55. Subsequently, anxiety or depression-like behaviors, BDNF levels, oxidative stress markers and mRNA expression of BDNF and 5HT₃ in the PFC were assessed.

RESULTS

Stressed rats demonstrated enhanced anxiety levels and depression-like behaviors in adulthood. Regarding the oxidative stress markers, stressed rats exhibited significantly higher levels of malondialdehyde, a lipid peroxidation product, higher activities of antioxidant enzymes (glutathione peroxidase and superoxide dismutase) and significantly lower total antioxidant reactivity capacity in the PFC. Additionally, adolescent stress significantly increased 5HT3 receptor mRNA expression and decreased BDNF content and its mRNA expression in the PFC. Treatments with SP, EX, EE, and the combined interventions alleviated these deficits.

CONCLUSION

Our findings indicate that appropriate interventions during the adolescent period can protect against adolescent stress-induced behavioral, and biochemical defects and oxidative stress damage in adulthood.

The State of Peripheral Blood Natural Killer Cells and Cytotoxicity in Women with Recurrent Pregnancy Loss and Unexplained Infertility

Background

The prognostic value of peripheral natural killer (pNK) cells, as a screening test in women with recur- rent pregnancy loss (RPL) and unexplained infertility, is still a matter for discussion. The purpose of this study was to compare the percentage of circulating CD56⁺NK cells, CD69 and perforin markers between women with unexplained infertility and RPL with the healthy control group.

Materials and Methods

In this case-control study, the percentage of CD56⁺NK cells and activation markers (CD69 and perforin levels) in the peripheral blood were measured in 25 women with unexplained infertility, 24 women with idiopathic RPL and 26 women from the healthy control group, using specific monoclonal antibodies by flow cytometry.

Results

The percentage of CD56⁺NK cells was significantly higher in patients with infertility in comparison with the healthy control group (P=0.007). There were not significant differences either in the total number of CD56⁺cells between the RPL group and the control group (P=0.2) or between the RPL group and the infertile group (P=0.36). The percentage of CD69⁺lymphocytes in RPL group was significantly higher than in the infertility group (P=0.004). There was a statistically significant difference in Perforin levels between RLP and control (P=0.001) as well as RPL and infertile (P=0.002) groups.

Conclusion

An increased percentage of CD56⁺NK cells in patients with unexplained infertility, an elevated expression of CD69 on NK cells in patients with RPL and infertility and a high level of perforin on CD56⁺cells in the RPL group might be considered as immunological risk factors in these women.

CRP and LOX-1: a Mechanism for Increasing the Tumorigenic Potential of Colorectal Cancer Carcinoma Cell Line

Chronic inflammation and dyslipidemia are associated with an increase in the incidence of colorectal cancer (CRC). Serum C- reactive protein (CRP) and oxidized low-density lipoprotein (oxLDL), as Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) ligands, increase during inflammation and dyslipidemia, respectively. To evaluate the effects of CRP on the expression of important genes involved in the development of CRC, the CRC cell line, LS174T, was treated with the commercial CRP. Based on the Real-time PCR data, in the presence of CRP, LOX-1, CEA, MMP1, and MMP2 mRNA expression significantly increased, compared to the control group. Moreover, in the presence of CRP, secretion, and expression of CEA in the cell lysate and conditioned media increased in a concentration-dependent manner. The results of flow cytometry showed that expression of LOX-1 receptors at the cell surface increased significantly in the presence of 10 mg/L of CRP. However, inhibition of LOX-1 receptors with a specific monoclonal antibody reduced the effects of CRP on protein/mRNA expression. In conclusion, Increased CRP level, can potentially elevate the expression of important genes in CRC by stimulating LOX-1 receptors.

The Effects of Mouse Recombinant Resistin on mRNA Expression of Proinflammatory and Anti-Inflammatory Cytokines and Heat Shock Protein-70 in Experimental Stroke Model

BACKGROUND

Our recent research showed that resistin has a neuroprotective effect against stroke-induced injury through suppressing apoptosis and oxidative stress. However, the molecular mechanism of neuroprotection of resistin is unclear. This work was designed to examine the effect of mouse recombinant resistin on mRNA expression of Tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-10 (IL-10), Transforming growth factor-β1 (TGF- β1), and Heat shock protein-70 (HSP-70) in mouse model of stroke.

MATERIALS AND METHODS

Transient focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) in mice. TNF-α, IL-1β, IL-10, TGF-β1, and HSP-70 mRNA were detected at sham (0 hour), 3 hours, 6 hours, 12 hours, and 24 hours after MCAO using real-time QRT-PCR method. Moreover, animals were treated with resistin at the dose of 400ng/mouse at the commencement of MCAO, and mRNA expression of the cytokines and HSP-70 was measured 24 hours after MCAO.

RESULTS

Tumor necrosis factor-α and IL-1β mRNA expression markedly increased at 12-hour time point and then returned to the basal level at 24 hours after MCAO; but HSP-70 mRNA expression increased at 24-hour time point. Furthermore, resistin (400 ng/mouse) significantly increased TGF-β1 and IL-10 and decreased HSP-70 gene expression at 24 hours after MCAO.

CONCLUSIONS

Our findings revealed that a molecular mechanism of attenuating ischemic damage by resistin administration probably is increased mRNA expression of anti-inflammatory cytokines. However, applying resistin in the clinical settings for the treatment of stroke deserves further researches in the future.

Phononic thermal conductivity in silicene: the role of vacancy defects and boundary scattering

We calculate the thermal conductivity of free-standing silicene using the phonon Boltzmann transport equation within the relaxation time approximation. In this calculation, we investigate the effects of sample size and different scattering mechanisms such as phonon-phonon, phonon-boundary, phonon-isotope and phonon-vacancy defect. We obtain some similar results to earlier works using a different model and provide a more detailed analysis of the phonon conduction behavior and various mode contributions. We show that the dominant contribution to the thermal conductivity of silicene, which originates from the in-plane acoustic branches, is about 70% at room temperature and this contribution becomes larger by considering vacancy defects. Our results indicate that while the thermal conductivity of silicene is significantly suppressed by the vacancy defects, the effect of isotopes on the phononic transport is small. Our calculations demonstrate that by removing only one of every 400 silicon atoms, a substantial reduction of about 58% in thermal conductivity is achieved. Furthermore, we find that the phonon-boundary scattering is important in defectless and small-size silicene samples, especially at low temperatures.

Mesenchymal Stem Cell Therapy Prevents Abortion in CBA/J × DBA/2 Mating

Immunological disorders are among the main causes of recurrent spontaneous abortions (RSAs). Mesenchymal stem cells (MSCs) have been shown to modulate various aspects of immune responses. It seems that MSCs may improve the immunological conditions in immune-mediated RSA. The aim of this study is the reduction of resorption in RSA mouse model through MSCs therapy. The adipose-derived MSCs were administered intraperitoneal to pregnant CBA/J mice on day 4.5 of gestation in abortion-prone matting. On day 13.5 of pregnancy, abortion rates were calculated and transforming growth factor-β (TGF-β), interleukin 10 (IL-10), interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α) gene expression in deciduas were evaluated by real-time polymerase chain reaction (PCR). The level of TGF-β in serum was also determined by enzyme linked immunosorbent assay (ELISA) method. The obtained results showed that MSCs therapy could reduce the abortion rate significantly in test group compared to controls. MSCs therapy also caused a significant upregulation of TGF-β and IL-10 and downregulation of IFN-γ and TNF-α genes expression in deciduas. However, the levels of TGF-β didn't change in mice sera. Due to the significant decrease in abortion rate, we concluded that MSCs therapy could modulate the immune responses in fetomaternal interface and protect fetus from undesirable immune responses. So, these cells might be considered as a new therapeutic for spontaneous pregnancy loss. The local upregulation of TGF-β and IL-10 and downregulation of IFN-γ and TNF-α gene expression in decidua could be considered as one possible mechanism of immune regulation, which could protect the fetus.

Prevalence of Neospora caninum and Toxoplasma gondii Antibodies in Bulk Milk of Dairy Cattle, Mashhad, Iran

Neospora caninum (N. caninum) and Toxoplasma gondii (T. gondii) are both obligate intracellular protozoan parasites, which have gained considerable attention because of their role in bovine abortion. This study aimed to detect anti-N. caninum and -T. gondii in bulk milk of dairy cattle, Mashhad, Iran. The bulk milk samples were collected from July 2014 to June 2015 and analyzed for anti-N. caninum and -T.gondii antibodies using enzyme-linked immunosorbent assay (ELISA). Out of 123 bulk milk samples, 44 (35%), 14 (11.38%), and 3 (2.4%) samples had N. caninum, T. gondii, and mixed infection with these two parasites, respectively. According to the results, the prevalence of N. caninum infection was more than T.gondii infection in dairy cattle of Mashhad, Iran.

Molecular Detection of Hepatozoon canis in Dogs of Ardabil Province, Northwest of Iran

Hepatozoon species are protozoan parasites that infect some animals such as birds, reptiles, amphibians, and carnivores. Previous studies performed on canine hepatozoonosis in Iran have never used molecular techniques for diagnosis of this disease. The main objective of the present study was to detect Hepatozoon canis in the blood of dogs using polymerase chain reaction (PCR) method and sequencing. A total of 104 blood samples were collected from dogs of Meshginshahr County (Ardabil Province), and DNA was extracted from blood samples by dint of DNG-plus Extraction Kit. Then, 18S rRNA gene was amplified by using the conventional PCR methods. PCR products yielded an amplicon of the approximate length of 897 bp for all the positive samples. Twenty-four out of the 104 (23.07%) samples were found to be positive for H. canis. This rate of infection is relatively high among dogs in Ardabil Province. Sequence analysis confirmed the molecular identity of 99% of the samples by comparison with GenBank profiles. This is the first report of molecular detection of H. canis from Iran.

Apoptosis/Necrosis Induction by Ultraviolet, in ER Positive and ER Negative Breast Cancer Cell Lines

Background:

Ultraviolet (UV) light exposure has been one of the major inducers of apoptosis. UV exposure has caused pyrimidine dimers and DNA fragmentation which might lead to cell cycle arrest and apoptosis signals activation. UV induced apoptosis has investigated in MDA-MB 468 as an ER negative breast adenocarcinoma and MCF-7 as an ER positive breast cancer cell line. Apoptosis induction rate by UV might be different in these two types of cells due to different biological characteristics of the cell.

Objectives:

In this paper we have evaluated serial dose of UV-B exposure on ER positive and ER negative breast cancer cell lines and its effect on apoptosis or necrosis induction in these cells.

Materials and Methods:

MDA-MB468 and MCF-7 cell lines have cultured for 24 hours and UV exposure has carried out at 290 nm at dose of 154 J/m² to 18 KJ/m² using UV lamp. UV exposed cells have incubated in cell culture condition for 24 or 48 hours following UV exposure and the cells have stained and analyzed by flow cytometry for apoptosis evaluation by Annexin V/PI method.

Results:

Apoptosis rate (PI and Annexin V double positive cells) after 24 hours incubation was higher in 24 hours in comparison with 48 hours incubation in both cell lines. The frequency of PI positive MDA-MB 468 cells was higher than PI and Annexin V double positive cells after 48 hours. PI positive MDA-MB 468 cells were significantly higher than MCF-7 cells in 24 hours incubation time.

Conclusions:

The results have shown that MDA-MB 468 cells were more sensitive to UV exposure and DNA fragmentation and necrosis pathway was dominant in these cells.

Comparison of effects of age and sex on serum protein electrophoretic pattern in one-humped camels (Camelus dromedarius) in Semnan, Iran

The aim of this study was to evaluate the influence of age and sex on the concentration of total serum protein measured by the biuret method and protein fractions determined using cellulose acetate electrophoresis in apparently healthy camels (Camelus dromedarius). Blood samples were collected from 21 camels (12 males and 9 females). The camels were further divided into two groups: 12 young camels at the age of 3 months to 2 years and 9 adult camels at the age of 3-15 years. Cellulose acetate electrophoresis of serum proteins identified five protein fractions in adult camels as young camels, these five protein fractions include albumin, α1 and α2, β and γ-globulins. In adult camels, serum levels (g/l) of total protein, albumin, α1-globulins, α2-globulins, β-globulins and γ-globulins were 80.9±3.10, 42.9±3.10, 1.3±0.22, 2.2±0.30, 11.8±0.30 and 22.6±0.20, respectively. However, in young camels, these levels (g/l) were 66.8±2.90, 40.2±2.40, 1.0±0.14, 2.6±0.30, 10.6±0.80 and 12.3±1.20, respectively. The albumin/globulin (A/G) ratio was 2.08±0.28 in adult camels and 3.77±0.53 in young ones. The mean serum concentrations of total protein and γ-globulins were significantly (P<0.05) higher and the A/G ratio was significantly lower in adult camels compared to young camels. The mean concentrations of γ-globulins were significantly higher and the A/G ratio was significantly (P<0.05) lower in females compared to male camels. The results of the present study indicate a significant effect of age and sex on the concentrations of some of the serum protein fractions in dromedary camels.

Intensive Care Unit nosocomial sinusitis at the Rasoul Akram Hospital: Tehran, Iran, 2007-2008

BACKGROUND

Nosocomial rhino sinusitis causes major problems in all Intensive Care Units (ICUs).

OBJECTIVE

To describe incidence, epidemiologic, clinical manifestations, and microbiologic findings in ICUs admitted cases with nosocomial sinusitis. METHODS#ENTITYSTARTX00026;

MATERIALS

A prospective, cross sectional study done in Pediatric & Adult ICUs in Rasoul Akram Hospital; Tehran Iran (2007-2008). Para-nasal sinus computed tomography (CT) was performed in all adults with fever of unknown origin (FUO) within 48h of admission and repeated thereafter (4-7 days). Infectious sinusitis was diagnosed by microbiological analysis of sinus fluid aspirates.

RESULTS

Acute bacterial nosocomial sinusitis proved in 82% (51/ 63) of all cases. Head trauma was the most common cause; (n = 22, 45%) of cases. The results of culture were positive for 45 cases (82%). Of 45 culture positives, 19 yielded Gram negative organisms (41%) and 9 (22%) gave Gram positives (S. aureous, Streptococus spp). The remainders (n = 17, 37%) consisted of mixed aerobic/anaerobic bacteria. Seven cases, were positive in gram staining of sinus drainage and these were positive in culture for S. pneumonia (n = 5), Hemophilus influenza (n = 2). The type of organisms were not related to Glasgow Coma Scale in cases (P = 0.3).

CONCLUSION

Nosocomial organisms isolated were quite different from community acquired rhino sinusitis cases. Investigation of CT scan and drainage of Para-nasal sinuses would be helpful in undiagnosed FUO cases, especially in traumatic patients. Optimal treatment usually consists of removal of the tubes, mobilizing the patient, and administration the broad-spectrum antibiotics.

Evaluation of an interferon-gamma release assay in young contacts of active tuberculosis cases

In a cross-sectional study in a hospital in Tehran in 2006-08 the QuantiFERON-TB interferon-gamma release assay (QTB) was compared with the tuberculin skin test (TST) in 59 young people (aged < 20 years) with close contact with immunocompetent cases of proven pulmonary tuberculosis. After 1 year follow-up 10 subjects had progressed to tuberculosis disease and received treatment; TSTwas positive in 30% and QTB in 100%. Of the 49 non-progressive subjects, TST was positive in 10.4% and QTB in 16.3%. The agreement between TST and QTB assay in non-progressive subjects was poor (K = 0.43). False positive and false negative rates for TST were 40.0% and 9.3% respectively; positive and predictive values were 60.0% and 90.7%. We suggest adding the interferon assay to the skin test in the decision to perform chest X-ray or to start chemoprophylaxis at least in younger subjects (aged < 20 years).

Effect of thermal bond excitations on the critical properties of covalent Ising networks

We introduce a bond-diluted Ising model with temperature-dependent concentration of bonds, which is intended to simulate the excitations of bond degrees of freedom as in covalently bonded network liquids arising from the thermal electronic transitions between bonding and antibonding electronic states. The critical behavior of this simplified model system, called the thermalized-bond Ising model, is investigated in terms of the Monte Carlo simulation results of finite-size regular Ising systems, as input for the method of chemical potentials that is generally used to obtain the thermodynamic properties of annealed impurity models. A finite-size scaling analysis of the susceptibility and the fourth-order cumulant results in a reliable estimation of the renormalized critical exponents. The exponents are found to be consistent with the phenomenological renormalization relations, due to Fisher, despite the temperature-dependent bond dilution.

Angiotensin II-induced constrictions are masked by bovine retinal vessels

PURPOSE

To unmask the vasoconstricting effect of angiotensin II (Ang II) on retinal smooth muscle by studying its interaction with endothelium-derived paracrine substances. This study focused specifically on determining the changes in vascular diameter and the release of endothelial-derived vasodilators, nitric oxide (NO) and prostaglandin (PG) I2, from isolated retinal microvessels.

METHODS

Bovine retinal central artery and vein were cannulated, and arterioles and venules were perfused with oxygenated/heparinized physiological salt solution at 37 degrees C. This ex vivo perfused retinal microcirculation model was used to observe the contractile effects of Ang II on arterioles and venules of different diameters. The NO and PGI2 synthase inhibitors, 1-NOARG and flurbiprofen, respectively, were used to unmask Ang II vasoconstriction; the changes in vascular diameters were then measured. Enzyme immunoassays were used to measure the release of cGMP (an index of NO release) and 6-keto-PG-F1alpha (a stable metabolite of PGI2) from isolated bovine retinal vessels.

RESULTS

Topically applied Ang II (10(-10) M to 10(-4) M) caused significant (P < 0.05) arteriolar and venular constrictions in a dose-dependent manner, with the smallest retinal arterioles (7+/-0.2 microm luminal diameter) and venules (12+/-2 microm luminal diameter) significantly more sensitive than larger vessels. After the inhibition of endogenous NO and PGI2 synthesis by 1-NOARG and flurbiprofen, respectively, the vasoconstriction effects of Ang II became more pronounced. Again, the smallest vessels tested were significantly more sensitive, and synthesis of endothelial-derived relaxing factor (EDRF), therefore, may be most important in these vessels. Vasoactive doses of Ang II (10(-10) M to 10(-4) M) caused a dose-dependent increase in the release of NO and PGI2 from isolated bovine retinal vessels, indicating that the increase in EDRF may nullify direct Ang II-induced vasoconstriction. Interestingly, intraluminal administration of Ang II caused only vasodilation.

CONCLUSIONS

This study demonstrates that the retinal vascular endothelium acts as a buffer against the vasoconstricting agent Ang II via release of vasodilators NO and PGI2, and the vasoconstriction effects due to Ang II are most prominent in the smallest diameter vessels.