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31
result(s) for
"Shmuel, Ronit"
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Strong, weak and neuron type dependent lateral inhibition in the olfactory bulb
2019
In many sensory systems, different sensory features are transmitted in parallel by several different types of output neurons. In the mouse olfactory bulb, there are only two output neuron types, the mitral and tufted cells (M/T), which receive similar odor inputs, but they are believed to transmit different odor characteristics. How these two neuron types deliver different odor information is unclear. Here, by combining electrophysiology and optogenetics, it is shown that distinct inhibitory networks modulate M/T cell responses differently. Overall strong lateral inhibition was scarce, with most neurons receiving lateral inhibition from a handful of unorganized surrounding glomeruli (~5% on average). However, there was a considerable variability between different neuron types in the strength and frequency of lateral inhibition. Strong lateral inhibition was mostly found in neurons locked to the first half of the respiration cycle. In contrast, weak inhibition arriving from many surrounding glomeruli was relatively more common in neurons locked to the late phase of the respiration cycle. Proximal neurons could receive different levels of inhibition. These results suggest that there is considerable diversity in the way M/T cells process odors so that even neurons that receive the same odor input transmit different odor information to the cortex.
Journal Article
Non-invasive multiple cancer screening using trained detection canines and artificial intelligence: a prospective double-blind study
2024
The specificity and sensitivity of a simple non-invasive multi-cancer screening method in detecting breast, lung, prostate, and colorectal cancer in breath samples were evaluated in a double-blind study. Breath samples of 1386 participants (59.7% males, median age 56.0 years) who underwent screening for cancer using gold-standard screening methods, or a biopsy for a suspected malignancy were collected. The samples were analyzed using a bio-hybrid platform comprising trained detection canines and artificial intelligence tools. According to cancer screening/biopsy results, 1048 (75.6%) were negative for cancer and 338 (24.4%) were positive. Among the 338 positive samples, 261 (77.2%) were positive for one of the four cancer types that the bio-hybrid platform was trained to detect, with an overall sensitivity and specificity of 93.9% (95% confidence interval [CI] 90.3-96.2%) and 94.3% (95% CI 92.7%-95.5%), respectively. The sensitivity of each cancer type was similar; breast: 95.0% (95% CI 87.8-98.0%), lung: 95.0% (95% CI 87.8-98.0%), colorectal: 90.0% (95% CI 74.4-96.5%), prostate: 93.0% (95% CI 84.6-97.0%). The sensitivity of 14 other malignant tumors that the bio-hybrid platform was not trained to detect, but identified, was 81.8% (95% CI 71.8%-88.8%). Early cancer (0–2) detection sensitivity was 94.8% (95% CI 91.0%-97.1%). This bio-hybrid multi-cancer screening platform demonstrated high sensitivity and specificity and enables early-stage cancer detection.
Journal Article
A panel of human neutralizing mAbs targeting SARS-CoV-2 spike at multiple epitopes
2020
The novel highly transmissible human coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Thus far, there is no approved therapeutic drug specifically targeting this emerging virus. Here we report the isolation and characterization of a panel of human neutralizing monoclonal antibodies targeting the SARS-CoV-2 receptor binding domain (RBD). These antibodies were selected from a phage display library constructed using peripheral circulatory lymphocytes collected from patients at the acute phase of the disease. These neutralizing antibodies are shown to recognize distinct epitopes on the viral spike RBD. A subset of the antibodies exert their inhibitory activity by abrogating binding of the RBD to the human ACE2 receptor. The human monoclonal antibodies described here represent a promising basis for the design of efficient combined post-exposure therapy for SARS-CoV-2 infection.
Here, Noy-Porat, Makdasi et al. report the isolation of a panel of neutralizing mAbs selected against SARS-CoV-2 receptor-binding domain (RBD) from a phage display library constructed based on patient samples collected in the acute phase of the disease, which show efficient neutralizing activities against authentic virus in vitro.
Journal Article
Post-exposure protection of SARS-CoV-2 lethal infected K18-hACE2 transgenic mice by neutralizing human monoclonal antibody
2021
The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits high levels of mortality and morbidity and has dramatic consequences on human life, sociality and global economy. Neutralizing antibodies constitute a highly promising approach for treating and preventing infection by this novel pathogen. In the present study, we characterize and further evaluate the recently identified human monoclonal MD65 antibody for its ability to provide protection against a lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice. Eighty percent of the untreated mice succumbed 6–9 days post-infection, while administration of the MD65 antibody as late as 3 days after exposure rescued all infected animals. In addition, the efficiency of the treatment is supported by prevention of morbidity and ablation of the load of infective virions in the lungs of treated animals. The data demonstrate the therapeutic value of human monoclonal antibodies as a life-saving treatment for severe COVID-19 infection.
Here, using the K18-hACE2 transgenic mice model, the authors report the in vivo efficacy of a fully human neutralizing antibody against SARS-CoV-2 and show that when administered before or up to 3 days post infection, treated mice do not exhibit disease symptoms while 80% of control animals succumb to the infection.
Journal Article
Minor Clinical Impact of COVID-19 Pandemic on Patients With Primary Immunodeficiency in Israel
by
Confino-Cohen, Ronit
,
Agmon-Levin, Nancy
,
Frizinsky, Shirly
in
Adolescent
,
Adult
,
agammaglobulinemia
2021
In the last few months the world has witnessed a global pandemic due to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection causing coronavirus disease 2019 (COVID-19). Obviously, this pandemic affected individuals differently, with a significant impact on populations considered to be at high-risk. One such population, was assumed to be patients with primary genetic defect involving components or pathways of the immune system. While human immunity against COVID-19 is not fully understood, it is, so far, well documented, that both adaptive and innate cells have a critical role in protection against SARS-CoV-2. Here, we aimed to summarize the clinical and laboratory data on primary immunodeficiency (PID) patients in Israel, who were tested positive for SARS-CoV-2, in order to estimate the impact of COVID-19 on such patients. Data was collected from mid-February to end-September. During this time Israel experienced two “waves” of COVID-19 diseases; the first, from mid-February to mid-May and the second from mid-June and still ongoing at the end of data collection. A total of 20 PID patients, aged 4 months to 60 years, were tested positive for SARS-CoV-2, all but one, were detected during the second wave. Fourteen of the patients were on routine monthly IVIG replacement therapy at the time of virus detection. None of the patients displayed severe illness and none required hospitalization; moreover, 7/20 patients were completely asymptomatic. Possible explanations for the minimal clinical impact of COVID-19 pandemic observed in our PID patients include high level of awareness, extra-precautions, and even self-isolation. It is also possible that only specific immune pathways (e.g. type I interferon signaling), may increase the risk for a more severe course of disease and these are not affected in many of the PID patients. In some cases, lack of an immune response actually may be a protective measure against the development of COVID-19 sequelae.
Journal Article
Effect of Ovarian Stimulation and Trigger Protocols on Oocyte and Embryo Numbers—Real World Experience
by
Sela, Nitzan Dana
,
Izhaki, Ido
,
Beck-Fruchter, Ronit
in
Antagonist drugs
,
Birth rate
,
Body mass index
2025
Objectives: This retrospective single-center cohort study aims to evaluate the impact of dual-trigger therapy (recombinant hCG [rhCG] combined with GnRH agonist) compared to rhCG alone on ART outcomes in women undergoing GnRH antagonist protocols. Methods: Data from 1291 IVF cycles performed between 2016 and 2022 were analyzed. After propensity score matching (PSM) to adjust for confounders, 395 cycles in each group were compared. Primary outcomes included the total number of oocytes retrieved, while secondary outcomes assessed mature oocytes, fertilization rates, and embryo numbers. Results: Dual-trigger therapy yielded significantly more total oocytes (7.50 ± 5.23 vs. 6.12 ± 4.23, p < 0.001) and mature oocytes (5.67 ± 3.87 vs. 5.01 ± 3.13, p = 0.047) compared to rhCG alone. Cycles with no oocytes were fewer in the dual-trigger group (1.3% vs. 3.8%, p = 0.015). Total embryos were also higher with dual trigger therapy (2.43 ± 1.90 vs. 2.00 ± 1.93, p = 0.001). In intracytoplasmic sperm injection (ICSI) cycles, the fertilization rate significantly improved with dual trigger (64.93 ± 33.50% vs. 52.22 ± 34.12%, p = 0.003). No significant differences were noted in fertilization rates for standard IVF (55.14 ± 30.72% vs. 52.29 ± 32.11%, p = 0.18) or maturation rates (72.52 ± 26.91% vs. 71.53 ± 24.75%, p = 0.37). Conclusions: These findings demonstrate that dual-trigger therapy improves ART outcomes by increasing oocyte and embryo yields.
Journal Article
Spike vs nucleocapsid SARS-CoV-2 antigen detection: application in nasopharyngeal swab specimens
2021
Public health experts emphasize the need for quick, point-of-care SARS-CoV-2 detection as an effective strategy for controlling virus spread. To this end, many “antigen” detection devices were developed and commercialized. These devices are mostly based on detecting SARS-CoV-2’s nucleocapsid protein. Recently, alerts issued by both the FDA and the CDC raised concerns regarding the devices’ tendency to exhibit false positive results. In this work, we developed a novel alternative spike-based antigen assay, comprising four high-affinity, specific monoclonal antibodies, directed against different epitopes on the spike’s S1 subunit. The assay’s performance was evaluated for COVID-19 detection from nasopharyngeal swabs, compared to an in-house nucleocapsid-based assay, composed of novel antibodies directed against the nucleocapsid. Detection of COVID-19 was carried out in a cohort of 284 qRT-PCR positive and negative nasopharyngeal swab samples. The time resolved fluorescence (TRF) ELISA spike assay displayed very high specificity (99%) accompanied with a somewhat lower sensitivity (66% for Ct < 25), compared to the nucleocapsid ELISA assay which was more sensitive (85% for Ct < 25) while less specific (87% specificity). Despite being outperformed by qRT-PCR, we suggest that there is room for such tests in the clinical setting, as cheap and rapid pre-screening tools. Our results further suggest that when applying antigen detection, one must consider its intended application (sensitivity vs specificity), taking into consideration that the nucleocapsid might not be the optimal target. In this regard, we propose that a combination of both antigens might contribute to the validity of the results.
Journal Article
Curcumin Protects Skin against UVB-Induced Cytotoxicity via the Keap1-Nrf2 Pathway: The Use of a Microemulsion Delivery System
by
Kohen, Ron
,
Soroka, Yoram
,
Frušić-Zlotkin, Marina
in
Antioxidants
,
Apoptosis
,
Bioavailability
2017
Curcumin was found to be beneficial in treating several skin pathologies and diseases, providing antioxidant protection due to its reducing properties and its electrophilic properties (the ability to activate the Nrf2 pathway and induce phase II cytoprotective enzymes). Nevertheless, clinical applications of curcumin are being hampered by its insufficient solubility, chemical instability, and poor absorption, leading to low efficacy in preventing skin pathologies. These limitations can be overcome by using a nanotechnology-based delivery system. Here, we elucidated the possibility of using curcumin encapsulated in a microemulsion preserving its unique chemical structure. We also examined whether curcumin microemulsion would reduce UVB-induced toxicity in skin. A significant curcumin concentration was found in the human skin dermis following topical application of a curcumin microemulsion. Moreover, curcumin microemulsion enhanced the reduction of UV-induced cytotoxicity in epidermal cells, paving the way for other incorporated electrophiles in encapsulated form protecting skin against stress-related diseases.
Journal Article
Mice with induced pulmonary morbidities display severe lung inflammation and mortality following exposure to SARS-CoV-2
by
Stein, Dana
,
Politi, Boaz
,
Yitzhaki, Shmuel
in
ACE2
,
Angiotensin
,
Angiotensin-converting enzyme 2
2021
Mice are normally unaffected by SARS-CoV-2 infection since the virus does not bind effectively to the murine version of the ACE2 receptor molecule. Here we report that induced mild pulmonary morbidities render SARS-CoV-2 refractive CD-1 mice to be susceptible to this virus. Specifically, SARS-CoV-2 infection after application of low-doses of the acute-lung-injury stimulants bleomycin or ricin caused a severe disease in CD-1 mice, manifested by sustained body weight loss and mortality rates of >50%. Further studies revealed markedly higher levels of viral RNA in the lungs, heart and serum of low-dose-ricin pretreated, as compared to non-pretreated mice. Furthermore, lung extracts prepared 2-3 days after viral infection contained subgenomic RNA and virus particles capable of replication, only when derived from the pretreated mice. The deleterious effects of SARS-CoV-2 infection were effectively alleviated by passive transfer of polyclonal or monoclonal antibodies generated against SARS-CoV-2 RBD. Thus, viral cell entry in the sensitized mice seems to depend on viral RBD binding, albeit by a mechanism other than the canonical ACE2-mediated uptake route. This unique mode of viral entry, observed over a mildly injured tissue background, may contribute to the exacerbation of COVID-19 pathologies in patients with preexisting morbidities.
Journal Article
Fc-Independent Protection from SARS-CoV-2 Infection by Recombinant Human Monoclonal Antibodies
by
Makdasi, Efi
,
Yitzhaki, Shmuel
,
Rosenfeld, Ronit
in
a-glycosylated
,
Antigens
,
Cell activation
2021
The use of passively-administered neutralizing antibodies is a promising approach for the prevention and treatment of SARS-CoV-2 infection. Antibody-mediated protection may involve immune system recruitment through Fc-dependent activation of effector cells and the complement system. However, the role of Fc-mediated functions in the efficacious in-vivo neutralization of SARS-CoV-2 is not yet clear, and it is of high importance to delineate the role this process plays in antibody-mediated protection. Toward this aim, we have chosen two highly potent SARS-CoV-2 neutralizing human monoclonal antibodies, MD65 and BLN1 that target distinct domains of the spike (RBD and NTD, respectively). The Fc of these antibodies was engineered to include the triple mutation N297G/S298G/T299A that eliminates glycosylation and the binding to FcγR and to the complement system activator C1q. As expected, the virus neutralization activity (in-vitro) of the engineered antibodies was retained. To study the role of Fc-mediated functions, the protective activity of these antibodies was tested against lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice, when treatment was initiated either before or two days post-exposure. Antibody treatment with both Fc-variants similarly rescued the mice from death reduced viral load and prevented signs of morbidity. Taken together, this work provides important insight regarding the contribution of Fc-effector functions in MD65 and BLN1 antibody-mediated protection, which should aid in the future design of effective antibody-based therapies.
Journal Article