The impact of ABO blood types on humoral immunity responses and antibody persistency after different COVID-19 vaccine regimens.

This study evaluated the possible effects of blood types on coronavirus disease (COVID-19) vaccine immunogenicity and antibody (Ab) persistency. Five different vaccinated groups against COVID-19 were investigated at Pasteur Institute of Iran from April 2021 to December 2022. Anti-Spike IgG and neutralizing Ab rise were tracked on Day 21 as well as the humoral immune persistency assessment 180 after booster shots. Late adverse events up to 6 months after the booster dose were collected. The results showed that blood type A, led to a significantly higher anti-Spike Ab rise in AstraZeneca primed recipients in comparison with Sinopharm primed ones in heterologous regimens (p: 0.019). Furthermore, blood type O was a great co-effector in homologous AstraZeneca recipients regarding neutralizing Ab rise (0.013). In addition, blood type O led to a better anti-Spike Ab persistency in the Sinopharm homologous group whereas type A had the best effect on neutralizing Ab durability in the same vaccine group. What is more, Rh-positive individuals in AstraZeneca + PastoCovac Plus group had a higher rate of anti-Spike Ab rise (p = 0.001). Neutralizing Ab rise was also induced in AstraZeneca homologous and heterologous regimens of Rh-positive individuals significantly higher than Sinopharm primed cases. The present study showed the potential impact of blood types A/O and Rh-positive on a better humoral immune responses and Ab persistency. It is proposed that blood type A and Rh-positive could increase the Ab rise in AstraZeneca vaccinated individuals. Moreover, blood type O might be a better co-effector of anti-Spike Ab persistency in Sinopharm recipients.

Association between matrix metalloproteinase-9-1562C/T gene polymorphism and MMP-9 serum level in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease indicated by joint inflammation and cartilage destruction. Matrix metalloproteinase (MMP) enzymes play an influential role in inflammation by affecting the invasion and degradation of anatomical barriers. In this way, the current study investigated the relationship between the MMP-9-1562C/T gene polymorphism and this enzyme's serum level in RA. METHODS: The serum levels of MMP-9 in RA patients and healthy controls were measured using the enzyme-linked immunosorbent assay (ELISA). RA was confirmed using rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and C-reactive protein (CRP). Then the MMP-9-1562C/T gene polymorphism was analyzed utilizing polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Also, multivariate analysis investigated the connection between this polymorphism and the risk of RA. RESULTS: In this study, the increase of MMP-9 in patients due to the development of single nucleotide polymorphism in the promoter region of this gene (-1562 C→T) was confirmed by increasing the frequency of heterozygous genotype (CT). Logistic regression analysis also demonstrated that the chance of development of RA is higher in people with CT/CC genotype than in other alleles. CONCLUSIONS: We demonstrated that MMP-9-1562C/T gene polymorphism can play a significant role in the occurrence of RA.

Characterization of novel bacteriophage PSKP16 and its therapeutic potential against ß-lactamase and biofilm producer strain of K2-Hypervirulent Klebsiella pneumoniae pneumonia infection in mice model.

BACKGROUND: Severe infections caused by ß- lactamase producers, hypervirulent Klebsiella pneumoniae (BhvKp) with K2 serotype, highlight emergency need for new therapeutic strategies against this pathogen. We aimed to assess the efficacy of a novel phage, PSKP16, in the treating of pneumonia induced by BhvKp in mice models. METHOD: Genome sequences of PSKP16 were analyzed, and associated information can be found in NCBI. We applied treatment in two ways: by using mice for immediate and delayed treatments. Moreover, acute pneumonia obtained by BhvKp with intranasal method, was characterized in terms of histopathology of pulmonary lesions, biomarkers of inflammation level, leukocytes cells infiltration extent in mice, and was assessed treatment of them with PSKP16 multiplicity of infection (MOI: 10), either individually or in combination with gentamicin. Assessment of the ability of PSKP16 to inhibit BhvKp biofilm was studied. RESULTS: PSKP16 was associated with the Drexlerviridae family, and had a genome size of 46,712 bp, and 67 predicted ORFs. Herein, prompt phage administration's efficacy to decrease bacterial load and improve the survival rate in pneumonia models was faster than the synergism model with delay, but both almost displayed similar endpoints. The distribution of BhvKp strains in the lung was consistent with the histopathological findings, simultaneous inflammation, and level of serum tumor necrosis factor-α (TNF α). The phage treatment presented a lack of severe lesions and alveolar edema, reduction of inflammatory cell infiltration, which not only was it not associated with an over-inflammation but also provided a faster correction of blood cell count abnormalities compared to gentamicin. Phage with a high concentration in in vitro model effectively eliminated biofilms. CONCLUSION: It is essential to raise clinical awareness and management of BhvKp infections, signaled as the next superbug in waiting. The results of our study underscore the importance of PSKP16 as a phage with promising therapeutic potential in treating BhvKp-induced pneumonia.

Evaluation of ethanol and EDTA concentrations in the expression of biofilm-producing smf-1, rpfF genes in XDR clinical isolates of Stenotrophomonas maltophilia.

BACKGROUND: Stenotrophomonas maltophilia is able to cause infections in immunocompromised patients, and the treatment of this opportunistic pathogen is complicated due to its virulence factors, antibiotic resistance, and the ability of the bacteria to produce biofilm. The main goals of this study were to assess the susceptibility of extensively drug-resistant (XDR) isolates to ethanol and EDTA, and evaluating the synergistic effect of these disinfectants, and also survey the effect of exposure to sub-inhibitory concentrations of ethanol and EDTA on the expression of biofilm-producing smf-1, rpfF genes. RESULTS: The results showed that EDTA significantly increased the effectiveness of the ethanol and have a synergistic effect. All of the 10 XDR isolates included in the current study harbored smf-1 and rpfF genes and produced biofilm. After exposure to MIC, sub-MIC, synergism, and sub-synergism of ethanol and EDTA, the expression of smf-1 and rpfF genes was repressed significantly. CONCLUSION: In the current study, it was indicated that the expression of biofilm-producing genes was repressed when bacteria are exposed to different concentrations of ethanol and EDTA. Future studies should include more complex microbial communities residing in the hospitals, and more disinfectants use in hospitals. Expression of other virulence genes in different conditions is suggested.

In Vitro Activity of Fosfomycin on Multidrug-Resistant Strains of Klebsiella pneumoniae and Klebsiella oxytoca Causing Urinary Tract Infection.

With the emergence of multi-drug resistant strains among Klebsiella isolates, the use of old drugs such as fosfomycin has been considered. In this context, we investigated the effect of fosfomycin on biofilm-producing Klebsiella pneumoniae and Klebsiella oxytoca strains isolated from ICU patients. A total of 90 isolates of Klebsiella pneumoniae and 30 isolates of Klebsiella oxytoca were collected from the ICU ward. All isolates were confirmed by biochemical and genotypic methods. Antibiotic susceptibility testing was performed by disc diffusion method and for fosfomycin and colistin, minimum inhibitory concentration (MIC) was done using micro broth dilution. The presence of the beta-lactamase encoding genes, biofilm-related genes, and fosfomycin resistance-related genes was detected by PCR. Finally, for fosfomycin-resistant isolates, we determined the sequence type by the MLST method. Sensitivity rate to fosfomycin in Klebsiella pneumoniae and Klebsiella oxytoca isolates was 92.2% and 100%, respectively. Fosfomycin was the most active antimicrobial agent with 96% sensitivity among all tested antibiotics. All tested isolates could produce biofilm. The frequency of biofilm-related genes for Klebsiella pneumoniae was as follows: 95.5% fimH, 86.6% mrkD, 77.7% mrkA, and 50% wcaG. The frequency of these genes for Klebsiella oxytoca was as follows: 56.6% fimA, 46.6% mrkA, 93.3% matB, and 90% pilQ. Only 4.4% of Klebsiella pneumoniae isolates showed resistance to fosfomycin, and the fosA gene was detected in all of them. Our results showed that fosfomycin effectively inhibits multidrug-resistant (MDR) strains of Klebsiella pneumoniae and Klebsiella oxytoca.

Effects of acute exercise on memory: Considerations of exercise intensity, post-exercise recovery period and aerobic endurance.

Accumulating research demonstrates that acute exercise can enhance long-term episodic memory. However, it is unclear if there is an intensity-specific effect of acute exercise on long-term episodic memory function and whether this is influenced by the post-exercise recovery period, which was the primary objective of this experiment. Another uncertainty in the literature is whether aerobic endurance influences the interaction between exercise intensity and post-exercise recovery period on long-term episodic memory function, which was a secondary objective of this study. With exercise intensity and post-exercise recovery period occurring as within-subject factors, and fitness as a between-subject factor, 59 participants (Mage = 20 years) completed 12 primary laboratory visits. These visits included a 20-min bout of exercise (Control, Moderate, and Vigorous), followed by a recovery period (1, 5, 10, and 15 min) and then a word-list episodic memory task, involving an encoding phase and two long-term recall assessments (20-min and 24-h delayed recall). The primary finding from this experiment was that moderate and vigorous-intensity exercise improved memory function when compared to a non-exercise control. A secondary finding was that individuals with higher levels of aerobic endurance, compared to their lesser fit counterparts, had greater memory performance after exercise (moderate or vigorous) when compared to after a control condition. Additionally, individuals with higher levels of aerobic endurance, compared to their lesser fit counterparts, generally performed better on the memory task with longer post-exercise recovery periods. Future research should carefully consider these parameters when evaluating the effects of acute exercise on long-term episodic memory.

Evaluation of antibacterial activity of five biocides and the synergistic effect of biocide/EDTA combinations on biofilm-producing and non-producing Stenotrophomonas maltophilia strains isolated from clinical specimens in Iran.

BACKGROUND: The overuse of biocides in healthcare-facilities poses risk for emergence and spread of antibiotic resistance among nosocomial pathogens. Hospital-acquired infections due to S. maltophilia have been increased in the recent years and with its various resistance mechanisms contribute to patient morbidity and mortality in hospitals. The current study aimed to evaluate the susceptibility of biofilm-producing and non-producing S. maltophilia clinical isolates to five commonly used hospital biocides, alone and in combination with EDTA to examine the synergistic effect of combining EDTA on the bactericidal activity of them by microbroth dilution method. As well as the frequency of efflux genes encoding resistance to biocides among isolates. This study also intended to assess the effect of exposure of S. maltophilia isolates to sub-inhibitory concentrations of sodium hypochlorite upon the antimicrobial susceptibility patterns. RESULTS: Based on minimum inhibitory and bactericidal concentrations of biocides sodium hypochlorite 5% (w/v) and ethyl alcohol 70% (v/v) were the strongest and weakest biocides against S. maltophilia isolates, respectively. The combination of EDTA with biocides significantly increased the effectiveness of the studied biocides. Exposure to sub-inhibitory concentration of sodium hypochlorite showed a significant change in the susceptibility of isolates towards ceftazidime (p = 0.019), ticarcillin/clavulanate (p = 0.009), and chloramphenicol (p = 0.028). As well as among the isolates examined, 94 (95%) were able to produce biofilm. The frequency of sugE1 resistance genes was found in 90.7% of our clinical S. maltophilia isolates. None of the isolates carried qacE and qacEΔ1 gene. CONCLUSIONS: The current study recommended that using the mixture of biocides with EDTA can be effective in reducing nosocomial infections. Also, this study demonstrated that exposure to sub-inhibitory concentrations of sodium hypochlorite leads to reduced antibiotic susceptibility and development of multidrug-resistant S. maltophilia strains.

Phenotype and genetic determination of resistance to common disinfectants among biofilm-producing and non-producing Pseudomonas aeruginosa strains from clinical specimens in Iran.

BACKGROUND: Pseudomonas aeruginosa is a common pathogen in Hospitalized patients, and its various resistance mechanisms contribute to patient morbidity and mortality. The main aims of the present study were to assess the susceptibility of biofilm-producing and non-producing P. aeruginosa isolates to the five commonly used Hospital disinfectants, to evaluate the synergistic effect of selected disinfectants and Ethylene-diamine-tetra acetic acid (EDTA), and the effect of exposure to sub-inhibitory concentrations of Sodium hypochlorite on antimicrobial susceptibility test. RESULTS: The results showed that sodium hypochlorite 5% and Ethanol 70% were the most and least effective disinfectants against P. aeruginosa, respectively. The addition of EDTA significantly increased the effectiveness of the selected disinfectants. The changes in the antibiotic-resistance profiles after exposure to sub-inhibitory concentrations of disinfectants were observed for different classes of antibiotics (Carbapenems, Aminoglycosides, Cephalosporins, Fluoroquinolones). As well as near the all isolates harbored efflux pump genes and 117 (97.5%) of isolates produced biofilm. CONCLUSION: In the current study, the mixture of disinfectant and EDTA were the most suitable selection to disinfect Hospital surfaces and instruments. Also, it was clear that exposure to sub-inhibitory concentrations of Sodium hypochlorite results in resistance to some antibiotics in P. aeruginosa species. Strong and intermediate biofilm formers belonged to MDR/XDR strains. Future studies should include more complex microbial communities residing in the Hospitals, and more disinfectants use in Hospitals.

Molecular identification and phylogenetic analysis of free-living amoeba in the water resources of Arak, Iran.

The aim of the present study was to detect free-living amoeba (FLA) in the water resources of Arak, Iran using molecular tools. A total of 154 samples were collected from different water supplies. Molecular analyses, sequencing, and phylogenetic study were conducted to confirm the species and genotypes of FLA. Fisher exact test was used to determine the significance. Of 154 water samples, 19 (12.3%) samples were tested positive for FLA. Three genotypes of Acanthamoeba including T4, subtype D, and T5 were identified among the isolates. The pathogenicity assay showed that the isolate of Acanthamoeba in drinking water was highly pathogenic. Three species of Naegleria, including N. australiensis, N. pagei, and N. gruberi were found among the samples. Six isolates of Vermamoeba were identified as V. vermiformis. Meanwhile, three other species including Vannella sp., Vahlkampfia avara, and Stenamoeba polymorpha were also recovered from the water samples. Statistical analysis showed a significant difference between the various water resources contaminated with FLA. This is the first study to reveal the presence of S. polymorpha in water sources in Iran. According to the findings of the present study, health officials should be beware of potential public health impacts of FLA in water resources.

Vigorous-intensity acute exercise during encoding can reduce levels of episodic and false memory.

The potential benefits (veridical memory) and, importantly, costs (false memory) of acute exercise on memory in conjunction with the timing and type of exercise have not been fully studied. In Experiment 1, we employed a three-condition (15-minute vigorous-intensity acute exercise Before or During memory encoding, or a Control condition of watching a video), within-subjects, counterbalanced design. The procedures included an immediate and delayed (20-minute post encoding) free recall assessment. Veridical memory was determined by the number of studied words that were recalled, whereas false memory was determined by retrieving a non-presented, critical item. For veridical memory, Before was not different than Control (p = .42), however, During was worse than Before and Control (p's < .001). No differences occurred for false memory. Experiment 2 was conducted that included several additional exercise conditions (e.g., light-intensity exercise) during memory encoding, used a recognition task instead of a free recall task, and extended the long-term memory assessment out to 24-hours. Experiment 2 demonstrated that vigorous-intensity acute exercise during encoding reduced both veridical and false memory for related new items (p < .05). These findings demonstrate that the timing and intensity of exercise play an important role in influencing memory performance.

Activity of meropenem-vaborbactam against different beta-lactamase producing Klebsiella pneumoniae and Escherichia coli isolates in Iran.

We evaluated the activity of meropenem-vaborbactam against different beta-lactamase producing Klebsiella pneumoniae and Escherichia coli isolates. In our study antibiotic susceptibility testing, double disk synergy test, modified Hodge test were applied. Detection of ESBL, AmpC, and carbapenemase genes was performed by PCR. Multilocus sequence typing (MLST) analysis was done on OXA-48 producing K. pneumoniae strains. Our results showed that among E. coli and K. pneumoniae isolates, 41.1% and 40% of strains produced ESBL, respectively. Additionally, the prevalence of AmpC producing K. pneumoniae and E. coli was 4% and 45.5%, respectively. Altogether 64.2% of K. pneumoniae strains and one E. coli isolate produced carbapenemase. Among OXA-48 producing K. pneumoniae strains ST3500 and ST2528 were detected by MLST. Based on the phenotypic results of this study, vaborbactam was an effective inhibitor on the third-generation cephalosporin-resistant isolates (P < 0.0001). Meropenem-vaborbactam combination had the highest efficacy on KPC producing strains, and it had limited activity on isolates producing OXA-48 type beta-lactamases, whereas no effect was observed on NDM-1 producing isolates. Our study provided valuable information regarding the vaborbactam inhibitory effect on ß-lactamase-producing strains.

Survey of the association between polymorphisms of CTLA-4 exon 1 49 A/G genes with rheumatoid arthritis in Iran.

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which suppresses T cell proliferation, is a promising candidate for the susceptibility genes to rheumatic arthritis diseases (RA). This study aims to examine the association between the polymorphisms of the CTLA-4 exon 1(+ 49) genes with RA in the Qazvin city of Iran population. The polymerase chain reaction of genomic DNA-restriction fragment length polymorphism (PCR-RFLP) was applied to genotype the CTLA-4 exon 1(+ 49) polymorphisms in 105 RA patients and 90 control subjects. Laboratory diagnostic tests were also measured for RA and control groups. Our results did not demonstrate a significant difference in allele and genotype frequencies of the CTLA-4 exon 1(+ 49) between RA patients and the control group (p < .0001). There was no significant difference in age at onset, CRP, RF value in patients with RA according to the CTLA-4 polymorphisms; just anti-CCP showed a significant difference. Our data declared that polymorphisms of CTLA-4 exon 1(+ 49) genes are not correlated with RA susceptibility and its clinical and paraclinical manifestations.

Nasal Air Puff Promotes Default Mode Network Activity in Mechanically Ventilated Comatose Patients: A Noninvasive Brain Stimulation Approach.

OBJECTIVES: Coma state and loss of consciousness are associated with impaired brain activity, particularly gamma oscillations, that integrate functional connectivity in neural networks, including the default mode network (DMN). Mechanical ventilation (MV) in comatose patients can aggravate brain activity, which has decreased in coma, presumably because of diminished nasal airflow. Nasal airflow, known to drive functional neural oscillations, synchronizing distant brain networks activity, is eliminated by tracheal intubation and MV. Hence, we proposed that rhythmic nasal air puffing in mechanically ventilated comatose patients may promote brain activity and improve network connectivity. MATERIALS AND METHODS: We recorded electroencephalography (EEG) from 15 comatose patients (seven women) admitted to the intensive care unit because of opium poisoning and assessed the activity, complexity, and connectivity of the DMN before and during the nasal air-puff stimulation. Nasal cavity air puffing was done through a nasal cannula controlled by an electrical valve (open duration of 630 ms) with a frequency of 0.2 Hz (ie, 12 puff/min). RESULTS: Our analyses demonstrated that nasal air puffing enhanced the power of gamma oscillations (30-100 Hz) in the DMN. In addition, we found that the coherence and synchrony between DMN regions were increased during nasal air puffing. Recurrence quantification and fractal dimension analyses revealed that EEG global complexity and irregularity, typically seen in wakefulness and conscious state, increased during rhythmic nasal air puffing. CONCLUSIONS: Rhythmic nasal air puffing, as a noninvasive brain stimulation method, opens a new window to modifying the brain connectivity integration in comatose patients. This approach may potentially influence comatose patients' outcomes by increasing brain reactivity and network connectivity.

Evolution of antigen-specific immune responses in cutaneous leishmaniasis patients.

AIMS: Despite immunization appearing to be the most appropriate strategy for long-term control of the vector-borne leishmaniases, no sustainable vaccine is currently available against any form of leishmaniasis. We therefore evaluated, in the context of vaccine antigen candidates, antigen-specific immune response at various stages of cutaneous leishmaniasis (CL). METHODS AND RESULTS: Peripheral blood mononuclear cells (PBMC) isolated from healthy volunteers and CL patients (caused by either Leishmania major or L tropica) were incubated with crude Leishmania proteins (soluble Leishmania antigen; SLA), single recombinant proteins (TSA, LeIF, LmSTI1) or chimeric fusion proteins (LEISH-F2 and LEISH-F3). The concentrations of immune modulatory cytokines were then determined. While we did not detect appreciable antigen-specific IL-5 secretion, SLA induced secretion of interleukin (IL)-10 in cultures from early active lesion CL patients and even from healthy individuals. Conversely, interferon (IFN)-γ responses to SLA and recombinant proteins followed a similar pattern, developing only in the late active CL lesion phase. Once established, antigen-specific IFN-γ responses persisted in cured CL patients. CONCLUSION: Together, our results provide further insight into the development of immune responses during CL and further validate the selection of LEISH-F2 and LEISH-F3 as vaccine antigen candidates.

Phenotypic Identification and Genotypic Characterization of Plasmid-Mediated AmpC ß-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolates in Iran.

One of the mechanisms of Klebsiella pneumoniae and Escherichia coli resistance to ß-lactam antibiotics is the production of ß-lactamase enzymes. Among these are the AmpC ß-lactamases, which confer resistance to a class of antibiotics. However, little is known about the AmpC ß-lactamases of K. pneumoniae and E. coli clinical isolates in Qazvin, Iran. This study was designed to assess the AmpC ß­lactamases-producing strains and also identify the prevalence of AmpC ß­lactamases genes. Antimicrobial susceptibility tests were performed on 435 K. pneumoniae and E. coli isolates using disk diffusion technique. Plasmid-mediated AmpC genes were studied using a multiplex PCR assay. The AmpC ß-lactamase-producer isolates were studied by employing cefoxitin disk diffusion test, AmpC induction test, AmpC cefoxitin-EDTA test, and boronic acid disk test. Our results showed that of 46 (18.4%) cefoxitin-insensitive E. coli isolates, 10 (21.7%) were positive for AmpC ß-lactamase genes, among them 4 (8.69%) isolates were positive for blaDHA genes and 6 (13%) for blaCIT genes. Of 57 (30.4%) cefoxitin-insensitive K. pneumoniae isolates, 10 (17.5%) were positive for AmpC gene with 4 (6.34%) and 6 (9.5%) isolates positive for blaDHA and blaCIT genes, respectively. However, no MOX, ACC, FOX, or EBC genes were detected in the isolates. Considering the results of different confirmatory phenotypic tests, the AmpC cefoxitin-EDTA test showed a higher discriminatory power for detecting AmpC ß-lactamase-producing strains. The specificity and sensitivity of AmpC cefoxitin-EDTA were 77%, 100% for K. pneumonia and 70%, 90% for E. coli higher than the other two tests, respectively. Also, the authors demonstrated high prevalence rate for resistance to certain antibiotics, such as cefuroxime, trimethoprim-sulfamethoxazole, ampicillin, and cefotaxime. In conclusion, our study provided valuable information regarding the plasmid-mediated AmpC ß-lactamase gene content, antibiotic resistance, and confirmatory phenotypic tests for AmpC ß-lactamases in E. coli and K. pneumoniae isolates from clinical sources.

Sex and Age Determination by Measurement of Foramen Magnum Dimensions on Computer Tomography Scanning Study in the Iranian Population.

BACKGROUND: Individual distinguishing evidence may be an imperative field of measurable investigation which demonstrates higher correct expectation rates. This process of recognizable Evidence is facilitated by the assurance of sex and age. In circumstances where there are fragmented and mangled skeletal remains, sex assurance is moderately troublesome, and it becomes important to set up the precision of cadaver bones. Therefore, this study aims to evaluate sexual dimorphism and age determination by measuring foramen magnum (FM) dimensions in the Iranian population using digital computed tomography scan. METHODS: The study sample consisted of a modern adult Iranian population of 120 males and 109 females (age range: 15-50 years). Length, width, and area of FM, also FM index were measured on base skull computed tomography scan. RESULT: All of the parameters of FM (length, width, area, and FM index), were larger in men than women. The accuracy of sex determination was up to 50.2. The highest accuracy for sex determination was FM width (67.9). This study also helps craniofacial surgeon for exact reference value of FM, which are authorize neurosurgeons' accessibility to the brain stem approach and FM region with minimum retraction. CONCLUSIONS: It can be concluded from the result, that morphometric analyze of FM is useful for sex determination but cannot be suitable for age determination.

Theta Phase-dependent Modulation of Perception by Concurrent Transcranial Alternating Current Stimulation and Periodic Visual Stimulation.

Sensory perception can be modulated by the phase of neural oscillations, especially in the theta and alpha ranges. Oscillatory activity in the visual cortex can be entrained by transcranial alternating current stimulation (tACS) as well as periodic visual stimulation (i.e., flicker). Combined tACS and visual flicker stimulation modulates BOLD response, and concurrent 4-Hz auditory click train, and tACS modulate auditory perception in a phase-dependent way. In this study, we investigated whether phase synchrony between concurrent tACS and periodic visual stimulation (i.e., flicker) can modulate performance on a visual matching task. Participants completed a visual matching task on a flickering visual stimulus while receiving either in-phase (0°) or asynchronous (180°, 90°, or 270°) tACS at alpha or theta frequency. Stimulation was applied over either occipital cortex or dorsolateral pFC. Visual performance was significantly better during theta frequency tACS over the visual cortex when it was in-phase (0°) with visual stimulus flicker, compared with antiphase (180°). This effect did not appear with alpha frequency flicker or with dorsolateral pFC stimulation. Furthermore, a control sham group showed no effect. There were no significant performance differences among the asynchronous (180°, 90°, and 270°) phase conditions. Extending previous studies on visual and auditory perception, our results support a crucial role of oscillatory phase in sensory perception and demonstrate a behaviorally relevant combination of visual flicker and tACS. The spatial and frequency specificity of our results have implications for research on the functional organization of perception.

The effects of different protocols of physical exercise and rest on long-term memory.

Whilst there are many studies comparing the different effects of exercise on long-term memory, these typically adopt varying intensities, durations, and behavioural measures. Furthermore, few studies provide direct comparisons between exercise and different types of rest. Therefore, by providing a standardised methodological design, this study will ascertain the most effective intensity and protocol of exercise for the modulation of long-term memory, whilst directly comparing it to different types rest. This was achieved using the same old/new recognition memory test and an 80-90 min retention interval. Three experiments were performed (total N = 59), each with a three-armed crossover design measuring the extent to which physical exercise and wakeful rest can influence long-term memory performance. In Experiment 1, the effects of continuous moderate intensity exercise (65-75% HRmax), passive rest (no cognitive engagement) and active rest (cognitively engaged) were explored. In Experiment 2, continuous moderate intensity exercise was compared to a type of high-intensity interval training (HIIT) and passive rest. Experiment 3 observed the effects of low- (55-65% HRmax), moderate- and high-intensity (75-85% HRmax) continuous exercise. Across the three experiments moderate intensity exercise had the greatest positive impact on memory performance. Although not significant, HIIT was more effective than passive-rest, and passive rest was more effective than active rest. Our findings suggest that it is not necessary to physically overexert oneself in order to achieve observable improvements to long-term memory. By also investigating wakeful rest, we reaffirmed the importance of the cognitive engagement during consolidation for the formation of long-term memories.

Hippocampal and Retrosplenial Goal Distance Coding After Long-term Consolidation of a Real-World Environment.

Recent research indicates the hippocampus may code the distance to the goal during navigation of newly learned environments. It is unclear however, whether this also pertains to highly familiar environments where extensive systems-level consolidation is thought to have transformed mnemonic representations. Here we recorded fMRI while University College London and Imperial College London students navigated virtual simulations of their own familiar campus (>2 years of exposure) and the other campus learned days before scanning. Posterior hippocampal activity tracked the distance to the goal in the newly learned campus, as well as in familiar environments when the future route contained many turns. By contrast retrosplenial cortex only tracked the distance to the goal in the familiar campus. All of these responses were abolished when participants were guided to their goal by external cues. These results open new avenues of research on navigation and consolidation of spatial information and underscore the notion that the hippocampus continues to play a role in navigation when detailed processing of the environment is needed for navigation.

Isolation and identification of Acanthamoeba genotypes and Naegleria spp. from the water samples of public swimming pools in Qazvin, Iran.

Free-living amoeba (FLA), including Acanthamoeba and Naegleria are facultative parasites in humans. The amoeba have widespread distribution in various water sources. The aim of this study was isolation and molecular identification of Acanthamoeba and Naegleria isolated from swimming pools and also hot and cold tub waters in Qazvin province. The samples (166 water samples) were cultured to isolate and identify positive specimens. PCR (polymerase chain reaction) amplification, sequencing and phylogenetic analysis were conducted to confirm the isolated species and genotypes of amoeba. According to morphological characterizations, 18.6% of specimens were identified as FLA, which in 71% were Acanthamoeba by PCR method. Molecular analysis revealed that 36.3%, 18.1% and 4.5% of Acanthamoeba specimens were identified as T3, T4 and T11 Acanthamoeba genotypes, respectively. Protacanthamoeba bohemica (27.2%) and Acanthamoeba sp. (4.5%) were found among the specimens. The results of osmo-tolerance and thermo-tolerance assays demonstrated that 50% of T3 and 25% of T4 genotypes of Acanthamoeba were highly pathogenic parasites. The molecular approach showed the presence of Naegleria lovaniensis (9%) in hot tub water of swimming pools. This study demonstrated that the swimming pools and hot tub water in Qazvin province were contaminated with Acanthamoeba and Naegleria species.