The properties of the RuII compound are unperturbed by the chitosan structure, with NS‐RuCh exhibiting the typical metal‐to‐ligand charge‐transfer (MLCT) absorption and emission bands of RuII complexes. When crosslinks are made in the presence of IrO2 nanoparticles, such species are encapsulated within the nanofibers, thus generating the IrO2⊂NS‐RuCh system, in which both RuII photosensitizers and IrO2 water oxidation catalysts are within the nanofiber structures. NS‐RuCh and IrO2⊂NS‐RuCh have been characterized by dynamic light scattering, scanning electronic microscopy, and energy‐dispersive X‐ray analysis, which indicated a 2 : 1 ratio between RuII chromophores and IrO2 species. Photochemical water oxidation has been investigated by using IrO2⊂NS‐RuCh as the chromophore/catalyst assembly and persulfate anions as the sacrificial species: photochemical water oxidation yields O2 with a quantum yield (Φ) of 0.21, definitely higher than the Φ obtained with a similar solution containing separated Ru(bpy)32+ and IrO2 nanoparticles (0.05) or with respect to that obtained when using NS‐RuCh and “free” IrO2 nanoparticles (0.10). A fast hole‐scavenging process  involving the oxidized photosensitizer and the IrO2 catalyst within the IrO2⊂NS‐RuCh system is behind the improved photochemical quantum yield of IrO2⊂NS‐RuCh.The luminophore Ru(bpy) Restricted environment frees up reaction: Chitosan fibers with covalently linked RuII polypyridine complexes and encapsulated IrO2 nanoparticles exhibit a remarkable quantum yield of 0.21 for photoinduced water oxidation in sacrificial schemes. The restricted environment is held responsible for accelerating electron transfer steps, which are considered to be the basis of the efficiency of the overall photocatalytic process. The development of artificial photosynthetic systems, that is synthetic systems capable of efficiently converting light energy into chemical energy inspired by the photosynthetic process performed by natural organisms, is attracting a large interest nowadays, for both fundamental and applicative reasons, in particular because of the potential impact on renewable energy research.In this work, an abundant natural polymer, chitosan, is exploited as a useful environment to integrate light harvesting systems‐which can also play the role of initiator of the photoinduced charge separation process, that is the charge separation unit—and catalysts in order to achieve photoinduced water oxidation, considered one of the bottlenecks of water splitting. Chitosan is a well‐known amino‐polysaccharide Figure  characteII polypyridine complexes and loaded with iridium oxide nanoparticles as well‐known water oxidation catalyst. This is evidenced by modification of the absorption spectrum of the photosensitizer during the photocatalysis. Noteworthy, system (c) exhibits a significant higher stability than system (a), probably connected with the faster reaction involving the oxidized form of the sensitizer .It can be noted that the photostability of the systems based on Ru2⊂NS−Ru system, we performed flash photolysis experiments in presence of Na2S2O8. These experiments allow to gain kinetic information on the hole scavenging reaction between the oxidized photosentitizer and the catalyst, that is the key reaction in Equation (3).2+/IrO2/Na2S2O8 system, which is reported to be 8×102 s−1,III in NS‐RuCh by “free” IrO2 within the measured time window at the IrO2 concentrations used; Figure S7). The relevant acceleration of the hole scavenging in IrO2⊂NS‐RuCh is attributed to the increase in proximity of both photosensitizer and catalyst subunits, thanks to the restricted environment promoted by the chitosan nanofibers which play the role of concentrators. Such a relevant acceleration of the hole scavenging process is therefore hold responsible for the improvement in the photochemical quantum yield of molecular oxygen production .18, 192⊂NS‐RuCh made of crosslinked Ru‐decorated chitosan have been prepared, with IrO2 nanoparticles encapsulated within the fibers by synthetic design. The Ru(bpy)3‐type chromophores were covalently linked to the chitosan scaffold. Absorption and emission spectroscopy showed that the RuII polypyridine units keep their own spectroscopic and photophysical properties essentially unperturbed within the chitosan nanofiber. Photoinduced water oxidation takes place in the system in the presence of persulfate anions as sacrificial agents, with a quantum yield of 0.21, which is significantly higher than the quantum yield obtained for separated RuII chromophores and IrO2 catalyst in solution (0.05), as well as for the Ru‐decorated chitosan nanofibers and non‐encapsulated IrO2 nanoparticle catalyst (0.10) investigated for comparison purposes. The more efficient photochemical water oxidation in the IrO2⊂NS‐RuCh system is attributed to the restricted environment experienced by the photosensitizers and catalysts, and in particular to kinetic reasons; actually, a remarkably fast hole‐scavenging process between the oxidized photosensitizer and the catalyst occurs in IrO2⊂NS‐RuCh, with a rate constant of 7.4×104 s−1, which is about two orders of magnitude faster than the same process for isolated light‐harvesting chromophore and catalyst species in solution. This result strongly confirms that restricted environments can play important roles in the design of functional supramolecular assemblies for achieving efficient photochemical water oxidation.Nanosized fibers IrOSupporting Information available: Details of materials, synthesis and characterization, instrumentation, oxygen evolving experiments.The authors declare no conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.


Pan troglodytes), 16 Sumatran orangutans (Pongo abelii) and 18 siamangs  to assess the complexity and effectiveness of their gestural use. We found that, beyond interspecies variation, the number of gesture types used in a dyad was higher when individuals had stronger social bonds; the probability of accounting for others' attention increased with age, especially for visual gestures; and sequences were more likely used by younger or socially less integrated individuals. In terms of effectiveness, older individuals and those using fewer sequences were more likely to be responded to, while across dyads, the probability of obtaining a response was higher when both individuals accounted for the other's attention and when they used fewer sequences. Overall, this confirms the link between sociality and complex gestural use and suggests that more complex forms of communication, at least in terms of intentional use, may be more effective at achieving communicative goals.Gestures play an essential role in primate communication. However, little is known about how complexity of gestural use  relates to individual and dyadic measures of sociality and whether more complex gestural use is more effective in eliciting a response. We observed 19 captive chimpanzees (This article is part of the theme issue ‘Cognition, communication and social bonds in primates’. By using observational and experimental methods in wild and captive settings, researchers have started revealing the complexity of primate gestural communication, and the flexible way in which gestures can be used by different species ,2. To daPan troglodytes), for instance, the species repertoire size is quite large, but it can vary from less than 30 )The effectiveness of gestural communication varied across individuals and dyads. At the individual level, the probability of receiving a response was higher for older individuals, and for individuals using fewer sequences (M5-Ind). At the dyadic level, the probability of obtaining a response was higher when both individuals accounted for the recipients’ attention, and when they used fewer sequences, with no differences depending on their relationship quality (M5-Dyad). These findings confirm that the complexity and effectiveness of gestural communication in apes generally increase with age (e.g. ), as indFinally, our study evidenced some differences across species. First, we found that dyadic repertoire size was largest in siamangs, and smallest in chimpanzees (M1-Dyad), showing that, in siamangs, dyads generally used a higher proportion of gestures that belonged to the species repertoire. At first sight, given that repertoire size is generally considered a measure of communication complexity (see above), these results would suggest that gestural complexity is higher in siamangs. However, these results may also suggest that, in orangutans and especially in chimpanzees, social interactions among group members are less uniform, and dyads are more selective with regard to the kind of specific social interactions, the context and thus the gestures used with different social partners. Therefore, dyadic repertoire size may be larger in siamangs simply because they live in stable small groups with strong bonds between the adult pair, where there may be less variation in terms of possible social interactions (see  for a diOverall, our study confirms the link between sociality and complex gestural use and suggests that more complex forms of communication, at least in terms of intentional use, may be more effective at achieving the goals of communication. Through age and social experience, apes likely adapt their communication to the contingencies they experience, they learn to account for others' attentional states and decrease the use of gestural sequences, learn which gestures are more effective and how to best elicit a response by recipients. Future work will need to better account for the large inter- and intra-individual variation in how gestures are exactly produced, and further disentangle the relative contribution of social and ecological experiences to the development of complex gestural communication.


Lamiaceae family and native to the Mediterranean region, thyme is considered an important wild edible plant studied for centuries for its unique importance in the food, pharmaceutical, and cosmetic industry. Thyme is loaded with phytonutrients, minerals and vitamins. It is pungent in taste, yet rich in moisture, proteins, crude fiber, minerals and vitamins. Its chemical composition may vary with geographical location but is mainly composed of flavonoids and antioxidants. Previous studies have illustrated the therapeutic effects of thyme and its essential oils, especially thymol and carvacrol, against various diseases. This is attributed to its multi-pharmacological properties that include, but are not limited to, antioxidant, anti-inflammatory, and antineoplastic actions. Moreover, thyme has long been known for its antiviral, antibacterial, antifungal, and antiseptic activities, in addition to remarkable disruption of microbial biofilms. In the COVID-19 era, some thyme constituents were investigated for their potential in viral binding. As such, thyme presents a wide range of functional possibilities in food, drugs, and other fields and prominent interest as a nutraceutical. The aims of the current review are to present botanical and nutritive values of this herb, elaborate its major constituents, and review available literature on its dietetic and biological activities.A perennial wild shrub from the  Wild edible plants (WEPs) as defined by the food and agricultural organization (FAO) are “the plants that grow spontaneously in self -maintaining populations in natural or semi-natural ecosystems and can exit independently of direct human actions” . In factSpecifically, in the Mediterranean region, there are an estimated 25,000 to 30,000 species of WEPs, many of which are endemic to the region. The diversity of species in this region can rely on the ecological conditions, such as the convenient climate and the soil type . In addiLamiaceae family is particularly well represented in Lebanon, where 136 species belonging to 29 genera have been inventoried. Some of them can be considered main ingredients in popular Lebanese dishes as spices such as Origanum syriacum, Satureja thymbra, Thymbra spicata and Thymus vulgaris. Others are eaten as salads such as Salvia rosemarinus, Coridothymus capitatus, and Salvia fruticosa which are also used in traditional medicine as a cure for different diseases, such as microbial infections [Lamiaceae species involving their chemical composition and the antimicrobial activity of their essential oils, revealed that Lamiaceae species are mostly used against gastrointestinal infections [The fections . A studyfections . The benfections .Thymus vulgaris); it is one of the most important edible plants, having many benefits. Thyme is rich in phytonutrients, minerals, vitamins, flavonoids and antioxidants. In addition, the therapeutic effects of thyme and its essential oils, especially thymol and carvacrol, against various diseases were demonstrated in several studies. This is attributed to its multi-pharmacological properties that include, but are not limited to, antioxidant, anti-inflammatory, and antineoplastic actions. Moreover, thyme has long been known for its antiviral, antibacterial, antifungal, and antiseptic activities. The current review presents the history, botanical and morphological properties of thyme, together with its nutritive and chemical values, and reviews available literature on its major biological activities. Literature for this narrative review was collected by a search for published articles about thyme on PubMed and Google Scholar, to allow consideration of a large spectrum of available evidence on this herb. By surveying the current literature using the key words thyme, Thymus vulgaris, thyme essential oil, and thymol, authors were able to include pertinent studies and summarize their findings in a format accessible to the reader. Articles which do not specifically mention Thymus vulgaris or which do not relate to the physiological functions of this herb addressed in this review were excluded.One of the most popular WEPs native to the Mediterranean region including Lebanon is thyme . According to Jalas [Micantes, Mastichina, Piperella, Teucrioides, Pseudothymbra, Thymus, Hyphodromi and Serpyllum. T. vulgaris L. and T. zygis L. belong to the Western Mediterranean area. Thymus. T. vulgaris is native to Southern Europe, from Spain to Italy [T. vulgaris is the native species known, according to Talhouk et al. [The to Jalas  and Morato Jalas , 214 speto Italy . In Lebak et al. . Below, Kingdom: PlantaeSubkingdom: TracheobiontaSuperdivision: SpermatophytaDivision: MagnoliophytaClass: MagnoliopsidaSubclass: AsteridaeOrder: LamialesFamily: LamiaceaeThymus L.Genus: Thymus vulgaris L. [Species: garis L. T. vulgaris is a perennial, evergreen subshrub with a generally upright, woody-based stem. The leaves are arranged as whorls around the stem, evergreen and simple [T. vulgaris has a moderate growth rate. At maturity, it reaches 0.5 to 1 m in height and spreads over 0.5 to 1 m and sometimes 15 m on the ground as a green cover. It takes 2 to 5 years to reach its maximum height [T. vulgaris grows in groups on calcareous rocks. It does not need a lot of water but requires full sunlight. It has no invasive potential and can live for a maximum of 25 years [T. vulgaris is most affected by root rot disease. Finally, thyme can be propagated from seeds, cuttings or by layering [d simple . They had simple . T. vulgMany studies have been conducted on thyme species to identify their chemical composition. A wide variety of chemical compounds as well as essential oils constitute the main composition of thyme that varies with climate and geographical area. Investigations have reported that thyme contains 56.53% monoterpenes, 28.69% monoterpene hydrocarbons, 5.04% sesquiterpene hydrocarbons and 1.84% oxygenated sesquiterpenes . Thyme iTo determine the fractions of essential oils in the thyme herb, standardized and appropriate techniques are always recommended. Extraction followed by analytical characterization are the main steps followed to build the profile of essential oils in thyme. Using capillary electrochromatography coupled to diode array detection (CEC-DAD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), thymol and carvacrol  were detT. vulgaris contains at least six chemotypes of essential oils: thymol as the major constituent, carvacrol, p-cymene, ɤ-terpinene, linalool, β-myrcene and terpinen-4-ol as well as others referred to in Essential oils are natural mixtures of a large variety of components at different concentrations. Thyme is loaded with phytonutrients, minerals and vitamins that are vital for good health. These nutrients are known for their disease-preventing and health-promoting properties and contribute to the benefits of this herb. Thyme is particularly rich in vitamin A and vitamin C. Vitamin A is an antioxidant known for being vital in maintaining healthy mucus membranes and skin as well as good vision. Vitamin C is essential to resist infectious diseases and protects against harmful pro-inflammatory free radicals. Thyme also contains B-complex vitamins, mainly vitamin B6 (pyridoxine), that assists in maintaining the γ-aminobutyric acid (GABA) levels in the brain and acts as a stress reliever. Vitamin K, vitamin E and folic acid are also present in thyme . AccordiThyme is also loaded with minerals that are essential for good health. Its leaves form an excellent source of potassium, calcium, iron, manganese, magnesium and selenium. Potassium is an important component of cells and body fluids and controls heart rate and blood pressure. Iron is crucial in red blood cell formation, and manganese is a co-factor for the antioxidant enzyme, superoxide dismutase . A summaThe food industry, one of the largest industries across the globe, has encountered many changes throughout the last decades and shifted towards healthier applications and innovative products. The plant extract industry infiltrates the food industry since plants have been used historically as food preservatives. Plants contain phytochemicals that protect them from microbial contamination and spoilage.Plant extracts such as essential oils, have been used to preserve food, increase its antimicrobial activity and improve its organoleptic properties. Thymol, the main essential oil constituent in thyme, is well known for its antioxidant, anti-inflammatory and antimicrobial activity. Its usage in food, as well as dried thyme leaves, is limited almost entirely to the meat industry and as condiment to replace or decrease the use of unhealthy synthetic additives .When thyme is added to food, some features may be improved, such as storage conditions, composition, and antimicrobial activity due to its preservative properties. Moreover, the presence of antioxidants and micronutrients in thyme can reduce the bioactivity of the food commodity. The only limiting aspect of thyme addition in some foods is the development of a negative organoleptic effect that sometimes contributes to an unpleasant odor and taste . To counA review of major biological and therapeutic effects of thyme and its main constituents is presented below, with a focus on antioxidant, anti-inflammatory, anticancer, and antimicrobial properties. These properties are also represented in Oxidation is a chemical process during which electrons or hydrogen are transferred from a certain substance to an oxidizing agent . BesidesT. vulgaris and its reducing power that might be attributed to higher amounts of total phenols and flavonoids. It was explained that the phenolic compounds possessed antioxidant effects mainly due to their redox properties, which can play a significant role in adsorbing and neutralizing free radicals, quenching singlet and triplet oxygen, or decomposing peroxides.In general, the antioxidant properties possessed by thyme extracts is primarily due to their richness in phenolic compounds and is related to their ability to act as free radical scavengers, metal ion chelators and inhibitors of oxidative enzymes . SeveralThymus species collected from different regions of Iran using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and a reducing power assay. It was found that T. vulgaris was among the thymus species that possessed higher antioxidant activities than the others. Also, in a study performed by Roby et al. [Moreover, Lee and Shibamoto conducted a study to determine the antioxidant potential of volatile extracts isolated from various herbs and spices, including thyme, which produced better results, with an inhibitory effect similar to that of α-tocopherol or butylhydroxytoluene . Furthery et al. , thyme mT. vulgaris oil against aflatoxin-induced oxidative stress in male rats. The results indicated that the combined treatment with aflatoxins and the oil showed significant enhancements among all tested parameters that were more pronounced within the group which received the oil at a high dose [Findings of a study conducted by Zaborowska et al. showed that the stability of sunflower oil was prolonged by ethanol thyme extract that might be a potent antioxidant for its stabilization . Furtherigh dose .The in vitro antioxidant activity of thymol, a major polyphenolic compound in thyme, was investigated by Yu et al. . ResultsAdditionally, the efficacy of thymol and carvacrol as antioxidants in microencapsulated walnut oil was recently evaluated by Gursul et al. . It was The effects of thymol and carvacrol on sperm quality oxidative stress and the antioxidant system in rats was investigated by Güvenç et al., whose findings demonstrated that these compounds decreased oxidative damage and improved sperm quality . FurtherT. vulgaris oil and water extracts and their ability to detoxify the lipopolysaccharide (LPS)-induced inflammation and oxidative stress. According to their findings, these extracts were able to reduce the LPS-induced elevation in cyclooxygenase (COX)-2, nuclear factor-kappa B (NF-кB), inducible nitric oxide (NO) synthase (iNOS), TNF-α, and NO, and produced a more potent attenuating effect than dexamethasone for most of the studied inflammatory mediators.Inflammation is a complex, natural, protective response of body tissues as a defense mechanism against harmful stimuli, including pathogens and cellular injury ,46. The T. vulgaris essential oils were proven by significantly reducing carrageenan-induced paw edema in mice [T. vulgaris was found to reduce neutrophil infiltration during an inflammatory response in zebrafish [Golbahari et al.  conducte in mice . Furtherebrafish .T. vulgaris aqueous extract by evaluating its effect on NO production induced by LPS and interferon-γ (IFN-γ) in the murine macrophage cell line J774A.1, and by evaluating the scavenging activity and inducible nitric oxide synthase (iNOS) mRNA expression. Findings revealed a significant dose-dependent inhibition in NO production that is induced by LPS and IFN-γ, scavenging of NO radicals released by an NO donor, PAPA-NONOate, and inhibition of iNOS mRNA expression [A study has also assessed the anti-inflammatory potential of pression . Anotherpression .Cancer is considered a serious threat globally . It rankThyme possesses numerous compounds, especially the monoterpenoid phenols carvacrol and thymol, which have great potential to be used in therapeutic and management interventions against cancer due to their pharmacological properties ,63,64. CT. vulgaris were evaluated in vivo and in vitro in mammary carcinoma models where two concentrations (0.1% and 1%) of dried T. vulgaris were continuously administered in the diet of a chemically-induced rat mammary carcinomas model and a syngeneic 4T1 mouse model. It was found that T. vulgaris at both doses reduced the volume of 4T1 tumors by 85% (0.1%) and 84% (1%) in mice compared to the control and the treated tumors showed a substantial decrease in necrosis/tumor area ratio and mitotic activity index. Furthermore, carcinoma cells showed a decrease in CD44, VEGFR-2, and ALDH1A1 expression, a decrease in malondialdehyde (MDA) levels, a decrease in the lysine methylation status of H3K4me3, and an increase in Bax expression. This showed that T. vulgaris has significant chemopreventive and therapeutic activities against experimental breast carcinoma [T. vulgaris extracts were reported to inhibit the proliferation of colorectal HCT116 cancer cell lines, increase their apoptotic cell death, and reduce their adhesion to fibronectin [T. vulgaris L. essential oil was also analyzed against the breast adenocarcinoma (MCF-7) cell line, lung carcinoma (H460) cell line and acute lymphoblastic leukemia (MOLT-4) cell line, revealing a dose-dependent inhibition of cell proliferation in all tested tumor cell lines with different sensitivities [The antitumor effects of arcinoma . Additioronectin . The anttivities . Thyme etivities .Thymol demonstrated proapoptotic and antiproliferative properties in lung, breast and prostate cancer cell lines, hence, it could serve as a potential therapeutic agent in the future . A study2/M phase [0/G1 phase, augmentation of ROS generation and disruption of the mitochondrial membrane potential were induced, in addition to apoptosis, confirmed by activation of caspase-3.Several studies have demonstrated that carvacrol exhibits strong antitumor effects and it was shown to be more cytotoxic compared to thymol ,76. In r/M phase . Further/M phase  demonstr/M phase  examinedT. vulgaris being the most investigated species [Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa [Like other plants, and due to biological and structural diversity of its components, thyme may be considered a renewable source for diverse antibacterial compounds, with  species . Globallruginosa . Severalruginosa . Data shruginosa . In the ruginosa . As suchruginosa .The British Herbal Pharmacopoeia classifies thyme as a medicinal plant, and among the indications for its use, it mentions bronchitis, bronchial catarrh, whooping cough, and sore throat, and recommendations are given for combining it with other plants. Attempts to characterize the antimicrobial properties of thyme in the laboratory date back to the early 1900s [T. vulgaris, where reference strains of S. aureus ATCC 25923, K. pneumoniae ATCC 13882, Salmonella typhimurium ATCC 14028, P. aeruginosa ATCC 27853, E. coli ATCC 25922, and Enterococcus faecalis ATCC 29212 were exposed to different concentrations of the essential oil. The study revealed that thyme essential oil was mostly effective against S. aureus and K. pneumoniae, while its potency against other strains was dose dependent. The results demonstrated that the essential oil possesses strong antimicrobial properties, and may designate a new birthplace of natural antiseptics with uses in both the pharmaceutical and food industry [The antiseptic qualities of thyme as an aromatic and medicinal plant have been recognized since antiquity, and it has been used to treat malaria since the sixteenth century. ly 1900s . The essly 1900s ,89 assocE. coli O157:H7, which remains an important contaminant in food production, and should be efficiently eliminated from meat, milk, water, vegetables, fruits and fruit juices. Thyme essential oil was shown to possess significant in vitro colicidal and colistatic activity over a broad temperature range, and this was substantially improved by the addition of agar as stabilizer in the testing medium. These findings indicated that thyme essential oil could be further examined for application in the food industry to improve food safety. These original findings were recently augmented by the use of thyme oil nanoemulsions aided by ultrasound to decontaminate the surface of vegetables against E. coli O157:H7 [E. coli O157:H7. Treatment with enterocin A alone did not affect the growth of E. coli O157:H7. However, the combination of thyme essential oils and enterocin A yielded a synergistic antimicrobial effect and a decrease in the minimum inhibitory concentration (MIC) of the essential oil. The combination exhibited enhanced bactericidal effect against Listeria monocytogenes, a foodborne pathogen. These data indicate that the combination may be exploited as a suitable control strategy for E.coli O157:H7 and L. monocytogenes, considering both economical aspects and the food flavor, and holding the additional promise of minimizing the development of resistance [E. coli O157:H7 and vancomycin-resistant enterococci, adding to the repertoire of food contaminants towards which this oil shows antibacterial activity [L. monocytogenes, S. typhimurium, and enterohemorrhagic E. coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens), thyme essential oil was tested. The essential oils of cinnamon, oregano, and thyme had the strongest antibacterial activity attributed to the key bioactive constituents, namely cinnamaldehyde, carvacrol, and thymol. This suggests thyme essential oil as a further alternative for food safety whose efficiency warrants further evaluation [Burt and Reinders  examined O157:H7 . Moreovesistance . Furtheractivity ,95. In aaluation .Staphylococcus, Enterococcus, Escherichia, and Pseudomonas genera, that were isolated in the hospital setting from infections of the oral cavity, abdominal cavity, respiratory tract, genitourinary tract, and skin. Using an agar diffusion method, the essential oil of thyme was shown to strongly inhibit the growth of the tested clinical strains, suggesting that it may be reasonable to investigate it as a phytopharmaceutical for treatment and prevention of bacterial infections caused by both Gram-positive and Gram-negative bacteria [E. coli strains isolated from patients with various conditions, where thyme essential oil was active against all the strains and was more potent than other oils [A. baumannii and K. pneumoniae, thyme essential oil decreased the MIC of the antibiotic colistin by 8- to 64-fold and 8- to 128-fold in colistin-resistant and colistin-susceptible strains. Hence, the essential oil of thyme can improve the efficacy of colistin and significantly reduce its concentration needed to inhibit both bacteria, and can be tested as a promising antimicrobial adjuvant [E. coli. This research laid the groundwork for further study into the potential of thyme as an alternate or supplemental treatment for urinary tract infections [Apart from foodborne pathogens, and as far as clinical strains are concerned, data on the activity of thyme against multidrug resistant clinical bacteria are accumulating. Almost a decade ago Sienkiewicz et al. explored the antimicrobial activity of thyme essential oil against clinical multidrug resistant bacteria . The resher oils . In a readjuvant . Loose efections .Streptococcus species, data have been documented for S. mutans, that causes dental caries but might also cause infective endocarditis [S. pyogenes that causes sore throat or pharyngitis [S. suis [Pseudomonas stutzeri, Enterococcus faecium and Bacillus thuringiensis). The nano-emulgel revealed bacteriostatic and biofilm inhibition properties, and improved skin histological structures in rat models, indicating potential for a bacteriostatic action and non-antibiotic microbial pathway inhibition as a topical clinical alternative to available agents [Salmonella Enteritidis treatment in poultry farms, decreasing the fecal content and mortality rate due to this pathogen [Regarding the effect of thyme on carditis , S. pyogryngitis , and the[S. suis ,104. Inte agents . Preparepathogen .Despite such promising data, challenges remain for the proper incorporation of thyme and its oil as agents directed towards infection. These include low water solubility, sensitivity to light, moisture, heat, and oxygen, and various chemical and structural instabilities, in addition to the need for clinical data. Recent efforts for the nanoliposomal formulation of thyme essential oil and its encapsulation in chitosan nanoparticles are being attempted and may represent a valid alternative to circumvent some of these challenges in the interest of thyme oil use for antibacterial and food safety purposes ,108.The antifungal activity of thyme is mainly contributed to the phenolic compounds, thymol and carvacrol, where the latter was reported more than two decades ago, to have potent fungitoxic activity when tested on fruits to inhibit the growth of fungi . RegardiCandida, some species of which are opportunistic pathogens and cause infections in immunocompromised or otherwise impaired hosts. Infections may be superficial or invasive, with the latter possibly life-threatening. Azoles and echinocandins are antifungal drugs used globally to treat Candida infections. However, resistance to these antifungal drugs has increased in many species, adversely affecting clinical settings and patient treatment [Candida and its potential as a source of anti-candidal agents form a large body of literature. For example, the essential oil of thyme was studied against fluconazole-resistant isolates of C. albicans isolated from the blood or vagina. It successfully reduced the growth of the isolates on culture media and was fungistatic and fungicidal at low doses. The oil also inhibited germ tube formation and budding of fungal pathogens, and was more effective against resistant isolates than fluconazole [C. albicans to change it morphology and form biofilms is central to its pathogenesis, as well to augmenting its resistance to antifungal agents [Candida. In one study, thymol caused disaggregation and deformed shape of C. albicans biofilm cells and reduced hyphae formation in C. tropicalis biofilm. Also, thymol showed synergy with fluconazole against both the planktonic and biofilm modes of growth in both species [C. albicans cell wall, cell membrane, cytoplasm, and vacuoles, illustrating a multidirectional action together with the anti-biofilm activity [Candida biofilm formation by at least 50% [C. albicans, along with changes in cellular and colonial morphology and in metabolic pathways like loss of the ability to assimilate saccharides. It was anticipated that such changes have a significant impact on C. albicans ability to cause infection. Apart from C. albicans, and considering non-albicans species and rare yeast species increasingly emerging as major opportunistic pathogens, thymol inhibited the growth of uncommon yeasts in vitro, suggesting it as a possible natural adjuvant for infections caused by those organisms [Among the most common pathogens in fungal infections is reatment . As suchconazole . In factl agents . As such species . In anotactivity . Recentleast 50% . Furthereast 50%  showed trganisms .Candida, many species of the fungal genus Aspergillus can harm the health of plants, animals, and humans by direct infection and/or the formation of harmful secondary metabolites known as aflatoxins, which are among the most noxious mycotoxins [Aspergillus flavus. Thyme essential oil exhibited antifungal activity through apoptosis, nuclear condensation, and plasma membrane damage. Additionally, the oil decreased aflatoxin production and gene expression and adversely affected secondary metabolism and mechanisms of virulence. In the assessment of 25 different plant essential oils against indoor species of Aspergillus, a study by Helbová et al. proved that thyme oil, combined with lemongrass oil, was the most potent synergistic antifungal against A. fumigatus. The synergistic combination may be useful for control of fungal growth or decreasing resistance to available synthetic antifungals [Aspergillus, Penicillium, Ulocladium, Absidia, Mucor, Cladosporium, Trichoderma, Rhizopus, and Chaetomium, isolated from wall scrapings of damp dwellings in Croatia. This indicated potential for use of thymol or thyme essential oil at low concentration for disinfection of moldy walls [Cryptococcus neoformans [C. neoformans. Among other pathways, thymol was found to regulate multiple signaling of calcineurin, and to reduce endogenous ergosterol content by decreasing the expression of ergosterol biosynthesis genes [Microsporum and Trichophyton, primary genera of dermatophytes obtained from clinical specimens, envisioning a natural alternative for topical antifungal drugs [Besides cotoxins . A recencotoxins  investigifungals . Thymol,dy walls . Thyme poformans , a fungais genes . In termal drugs . A nano-al drugs , perhapsLamiaceae, the aqueous extract of thyme was tested against herpes simplex viruses type 1 and type 2 (HSV-1 and HSV-2) in a German study. The extract was able to inhibit both types of viruses in cell lines, affecting the viruses prior to being adsorbed on the surface of cells but not affecting intracellular viral replication. This shed a light on the prospective of these extracts for topical therapeutic application against recurrent herpes infections [Among other extracts from the family fections . The resfections , who demfections . Some stfections ,131, sugRecently, and with the coronavirus disease, COVID-19, perplexing healthcare systems and societies, intensive efforts to develop effective preparations against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) were prominent, and natural compounds were not an exception. In this regard, the United States Environmental Protection Agency (EPA) placed thymol on the list of disinfectants with evidence for use against COVID-19, for disinfection of external hard surfaces and hands in healthcare, institutional, or residential applications . Thyme eWith both thymol and thyme essential oil having been therapeutically used for a long time as an expectorant, anti-inflammatory, anticancer, antibacterial, antiseptic, and antiviral, the current search for new directions in biological or pharmacological activities looks very promising. Likewise, the new formulations of thyme, such as nanogels and microemulsions, can be beneficial in medicinal practice and may create surplus opportunities for better use. In this regard, and to get the best possible from this rich herb, innovative approaches and a systematic method to experimentation with thyme are warranted. This includes establishment of a standard methodology for molecular and mechanistic studies, in addition to better transfer of the data obtained by experimentation into clinical trials, which are still not numerous for this herb. To be able to take full advantage of thyme and its ingredients and completely process them, high quality, advanced phase, randomized, placebo-controlled, multi-centered, randomized, and double-blind clinical trials are needed.In addition to the major health benefits well documented for thyme, along with the investigated pharmacological properties, there are several traits of this herb that need to be further examined. These include but are not limited to antidiabetic potential, dental decay inhibition, antihelminthic (antiparasitic) properties, and skin protection against ultraviolet radiation . The eviThe judicious review of thyme and its biological activities presented in this work is not without limitations. First, since this work is a narrative review rather than a systematic one, it is possible that some studies on thyme may not have been properly identified and included as needed, in order to be representative of the totality of evidence available on this culinary and medicinal herb. Second, the probability of bias, including influence of the authors’ personal viewpoints, gaps in the literature, probable omission of relevant research, and errors in the translation of data from primary literature about thyme, may all have affected our presented data. Third, with the large number of studies on thyme being reviewed, the quality of the available literature is expected to be heterogeneous, affecting our judgement. An ongoing inquiry on thyme in a more systematic fashion and more critical analysis of the available data is anticipated to circumvent these limitations.The current status of knowledge regarding thyme depicts a wide plethora of nutritional and therapeutic benefits and provides powerful recommendations for future research directions. With many previous valuable papers reviewing this WEP ,139,140,


Vulnerable plaques have been a hot topic in the field of stroke and carotid atherosclerosis. Currently, risk stratification and intervention of carotid plaques are guided by the degree of luminal stenosis. Recently, it has been recognized that the vulnerability of plaques may contribute to the risk of stroke. Some classical interventions, such as carotid endarterectomy, significantly reduce the risk of stroke in symptomatic patients with severe carotid stenosis, while for asymptomatic patients, clinically silent plaques with rupture tendency may expose them to the risk of cerebrovascular events. Early identification of vulnerable plaques contributes to lowering the risk of cerebrovascular events. Previously, the identification of vulnerable plaques was commonly based on imaging technologies at the macroscopic level. Recently, some microscopic molecules pertaining to vulnerable plaques have emerged, and could be potential biomarkers or therapeutic targets. This review aimed to update the previous summarization of vulnerable plaques and identify vulnerable plaques at the microscopic and macroscopic levels.  Worldwide, stroke contributes heavily to high mortality and disability rates . The maiC-reactive protein (CRP) is an inflammatory marker with no specificity that often accumulates in the macrophage-rich region of carotid plaques. Highly expressed CRP and high-sensitivity CRP (hs-CRP) indicate severe inflammation in plaques, implying plaque vulnerability . CompareMatrix metalloproteinase (MMP) is a kind of protease generated by inflammatory cells. Therefore, MMP is a classical inflammatory biomarker that is a potential risk factor for plaque rupture . The litA Disintegrin and metalloproteinase with Thrombospondin motifs (ADAMTS) family can degrade ECM because of proteolytic activity, and includes 19 proteases. They participate in inflammation, coagulation, angiogenesis, and organ development . A disinLectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a scavenger receptor for low-density lipoprotein cholesterol (ox-LDL). LOX-1 can combine with ox-LDL in the arterial wall, leading to endothelial cell dysfunction and ECM degradation . LOX-1 iNonhigh-density lipoprotein cholesterol (non-HDL-C) refers to the very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol and intermediate density lipoprotein cholesterol . IncreasPrevious studies reported that cholesterol crystals may be related to plaque vulnerability in coronary arteries . PlaquesFor patients with carotid stenosis ≥50%, higher triglycerides, and lower high-density lipoprotein cholesterol and tissue inhibitor of metalloproteinase 1 were detected in symptomatic patients than in asymptomatic patients . For symHigh serum free fatty acid (FFA) concentrations indicate high plaque vulnerability. FFAs are closely associated with lipid metabolism. Overly high serum FFA levels give rise to micelles and fatty acid vesicles with acidic cores fusing with endothelial cells, inducing plaques formation. Studies have suggested that high FFA levels are related to stroke events . The monocyte count in vulnerable plaques is significantly higher than that in stable plaques . CD163 iFor patients with high-grade internal carotid artery (ICA) stenosis, a higher level of plasma sCD36 is detected in those with recent symptoms than in those with remote symptoms. In plaques, CD36 is often present in intima with macrophage-gathering . In carotid plaques, CD146 is mainly located in infiltrated macrophages and blood vessels, and significantly correlated with MMP-9. Intraplaque CD146 positively correlates with serum sCD146. The serum sCD146 level is associated with IL-6, MMP-9, and hsCRP . COMP (cartilage oligomeric matrix protein), expressed by VSMCs, can interact with collagen I and growth factors , promoteSrc homology 2 (SH2) domain-containing protein tyrosine phosphatase 1 (SHP-1) is a classical nonreceptor protein tyrosine phosphatase. Immunohistochemical staining results show that SHP-1 shares similar distribution with CD68, such as in fibrous caps, plaque shoulders and necrotic areas. The expression of SHP-1 increases with the progression of carotid plaques. The increased protein expression of SHP-1 indicates a high plaque vulnerability. The underlying mechanism may be associated with the regulation of efferocytosis mediated by macrophage polarization . Serum macrophage CXC-chemokine ligand 16 (CXCL16) is a potential biomarker for carotid vulnerable plaques. Significantly higher serum CXCL16 levels were detected in vulnerable plaques and the micro-embolic signals (MES) positive group than in the stable plaque- and MES-negative groups. Serum CXCL16 levels rise with plaque area, lumen stenosis rate and intima-media thickness . Significantly increased expression levels of chemokine (c-c-motif) ligand 19 (CCL19) have been detected in vulnerable plaques. In addition, CCL19 often colocalizes with CD3+ T-cell lymphocytes. CCL19 may be a predictor for vulnerable plaques . MiRNA expression analysis carried out in atherosclerotic plaques has proven the important role that miRNAs play in vulnerable plaques . Higher A receptor of granulocyte macrophage colony-stimulating factor (GM-CSF), known as CSF-2R, includes two subunits (CSF-2Rα and CSF-2Rβ) . High exThe serum expression levels of miR-124, IL-1β and TNF-α in vulnerable plaques were significantly increased compared with those in stable plaques. In addition, the serum expression level of miR-124 positively correlates with IL-1β and TNF-α . The thrTransforming growth factor-beta (TGF-β) can regulate the proliferation and migration of cells, calcification and matrix synthesis . DACH1 (G-protein-coupled receptor 56 (GPR56) shows significantly differential expression levels between carotid stable plaques and vulnerable plaques in the carotid . GPR56 cDifferential expression of APoD has been found between stable plaques and vulnerable plaques in the carotid. ApoD participates in reverse cholesterol transportation and inhibits proliferation of VSMCs in culture . In addiBaculoviral IAP Repeat Containing 6 (BIRC6) is a ubiquitin-conjugating E2 enzyme that negatively modulates apoptosis and autophagy. BIRC6 can modulate the fusion of autophagosomes and lysosomes, inhibiting autophagy . In addiSerum osteoprotegerin , and preOsteopontin targeted theranostic nanoprobes have been proved to precisely regress vulnerable atherosclerotic plaques with the guidance of fluorescence/MR imaging . CleavedInsulin can decrease plaque vulnerability via nitric oxide synthase (NOS)-dependent mechanisms . NotablyFibrinogen belongs to the hemostatic system. The fibrinogen γ′ is a variant of fibrinogen. Fibrinogen γ′/total fibrinogen ratio is related to ischemic stroke . In receVon Willebrand Factor (VWF) can induce platelet adhesion and aggregation. ADAMTS13 can cleave ultralarge VWF multimers into smaller sizes. Both have been proven to be related to cerebral infarction . Other sBased on endothelial expression, increased expression levels of vascular cell adhesion protein-1(VCAM-1) have been detected in vulnerable plaques, compared with stable plaques. However, vWF, P-selectin, and LOX-1 do not show the potential for predicting vulnerable plaques, although they contribute heavily to plaque biology . Human cytomegalovirus (CMV) infection can lead to increased proliferation and impaired apoptosis. Persistent infection interrupts the normal function of endothelial cells (ECs) and activates the proinflammatory pathway related to specificity protein 1, nuclear factor κB, phosphatidylinositol 3-kinase, and platelet-derived growth factor receptor, promoting monocyte and SMC proliferation and migration into the vascular intima, as well as lipid accumulation and expansion within lesions . IntraplBCLAF1 (BCL2 (B-cell lymphoma 2)-associated transcription factor 1) participates in the transdifferentiation of SMC into a macrophage-like phenotype, serving as a potential marker of carotid vulnerable plaques . The transcription factor interferon regulatory factor-5 (IRF5) promotes macrophages to present a pro-inflammatory state, driving the formation and rupture of carotid vulnerable plaques in mouse carotid plaque rupture model . VSMCs are one of the major sources of CTH (cystathionine gamma-lyase)-hydrogen sulfide (H2S). Intraplaque CTH level positively correlates with collagen content and negatively correlates with CD68+ and necrotic core area. CTH- H2S attenuates atherosclerotic plaque vulnerability via TFEB (transcription factor EB)-mediated autophagy, serving as a biomarker of vulnerable plaques . Compared with carotid asymptomatic plaques, 2.2-fold upregulation of glutamine synthetase (GLUL) mRNA has been found in stroke-causing plaques. In the post-symptomatic period, a declined mRNA expression level of GLUL has been observed, indicating that GLUL may participate in plaque destabilization and rupture . The microscopic factors that potentially predict vulnerable plaques are summarized in 2) significantly correlates with histologically vulnerable plaques [2) may indicate vulnerable plaques [Ultrasound (US) is widely used in carotid atherosclerosis because of the features of fast examination, no radiation exposure , low cos plaques . The dis plaques . Usually plaques . In US i plaques . The jux plaques . A large plaques . A large plaques . Three-dimensional ultrasound (3D US) is an accurate and effective tool to evaluate the composition, volume, and morphology of plaques, even to monitor therapeutic effects on carotid plaques, improving the quantification and visualization of carotid plaques . In clinUltrafast ultrasound imaging (UUI) can assess stiffness and the distribution of stiffness inside plaques via shear wave elastography (SWE). SWE results show that stiffness range of 3–5 m/s is frequently observed in vulnerable plaques . Contrast-enhanced US (CEUS) is a novel and new noninvasive imaging technique  that canSome limitations of CEUS should be considered. In patients with carotid atherosclerosis, plaque neovascularization on CEUS may indicate the possibility of stroke recurrence. Notably, in plaques with severe calcification, CEUS may be less reliable . In addiMRI may be a relatively accurate method to evaluate IPH and stratify the risk of cerebrovascular events . IntraplMulticontrast high-resolution-MRI is a noninvasive technique with high spatial resolution that can detect and quantify the location, morphology and components of carotid plaques with adequate safety and high accuracy, sensitivity and specificity ,136,137.Further, 18F-Fluorodeoxyglucose (18F-FDG) is a common tracer of positron emission tomography (PET) examinations, which can noninvasively indicate intraplaque inflammation and glucose metabolism . Thus, 1Computed tomography angiography (CTA) can evaluate plaque morphology and components, as well as the lumen situation . CombineDigital subtraction angiography (DSA) is considered as the gold standard for diagnosing carotid atherosclerosis . HoweverOptical coherency tomography (OCT) can present high-resolution images via reflection of near-infrared light. High resolution OCT can identify plaque rupture or erosion, thickness and the macrophage content in fibrous caps, as well as subintimal lipid accumulation . BecauseFor patients with carotid plaques, imaging methods are necessary and convenient to evaluate the vulnerability of plaques. To date, various imaging methods have been proved to identify the vulnerable plaques. Vulnerable plaques consist of many types, such as IPH, neovascularization, and LRNC. Notably, each method has limitations and strengths, and solely one imaging method cannot cover all types of vulnerable plaques. In the future clinical practice, plaques should be evaluated by many imaging methods simultaneously based on individual situation. Combined with many imaging results, the evaluation of plaques may be reliable. In the early stage of plaque formation, thickened vascular wall and lumen stenosis can be compensated by arterial outer wall expansion, preserving the luminal area and blood flow . ExpansiCarotid atherosclerotic arteries show smaller artery tortuosity and bifurcation angles than healthy carotid arteries. In addition, tortuosity, bulb diameter, and bifurcation angle increase along with age, which may be attributed to fragmentation and degradation of elastin . CarotidIn the cerebrovascular system, a circle of Willis (COW) is vital for hemodynamic regulation . A previThe morpho-mechanical features of plaques can influence the shear stress, relating to the rupture tendency. Commonly, the proximal end of the stenosis suffers from higher shear stress than the distal part . CarotidThe “Crouse Score” quantifies the arteriosclerosis degree, defining IMT ≥ 1.1 mm as plaques. The carotid plaque score (CPS) can be calculated as the sum of maximal thickness of each single plaque on the bilateral carotid arteries . The CPSThe dietary inflammatory index (DII) represents the total inflammatory effect obtained from food. First, each food or nutrient is divided into proinflammatory or anti-inflammatory foods. Then, a value is assigned for each one based on the influence they exert on serum inflammatory markers. The DII is the sum of the values of all foods or nutrients . High DIPharmacokinetic modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) can help to noninvasively quantify plaque microvasculature. The volume transfer coefficient K trans reflects microvascular flow, density, and permeability. In addition, K trans is related to intraplaque macrophage accumulation, loose ECM and IPH . CompareAt the microscopic level, the underlying mechanisms of vulnerable plaques remain unclear. Further studies are needed to detect more potential molecular biomarkers and therapeutic targets. At the macroscopic level, serval imaging technologies currently have the capacity to identify classical features of vulnerable plaques, while some limitations still exist. Combined with potential microscopic mechanisms, developing novel detection technology, grasping the strengths and limitations of technologies and combining the appropriate technologies in necessity are conducive to the early identification and intervention of vulnerable plaques, thereby decreasing the subsequent risk of cerebrovascular events.


Elevated intracranial pressure (ICP) is observed in many neurological pathologies, e.g. hydrocephalus and stroke. This condition is routinely relieved with neurosurgical approaches, since effective and targeted pharmacological tools are still lacking. The carbonic anhydrase inhibitor, acetazolamide (AZE), may be employed to treat elevated ICP. However, its effectiveness is questioned, its location of action unresolved, and its tolerability low. Here, we determined the efficacy and mode of action of AZE in the rat .We employed in vivo approaches including ICP and cerebrospinal fluid secretion measurements in anaesthetized rats and telemetric monitoring of ICP and blood pressure in awake rats in combination with ex vivo choroidal radioisotope flux assays and transcriptomic analysis.AZE effectively reduced the ICP, irrespective of the mode of drug administration and level of anaesthesia. The effect appeared to occur via a direct action on the choroid plexus and an associated decrease in cerebrospinal fluid secretion, and not indirectly via the systemic action of AZE on renal and vascular processes. Upon a single administration, the reduced ICP endured for approximately 10 h post-AZE delivery with no long-term changes of brain water content or choroidal transporter expression. However, a persistent reduction of ICP was secured with repeated AZE administrations throughout the day.AZE lowers ICP directly via its ability to reduce the choroid plexus CSF secretion, irrespective of mode of drug administration.The online version contains supplementary material available at 10.1186/s12987-022-00348-6. AZE was launched in the early 1950s as a diuretic agent i in the choroid plexus tissue, may therefore directly affect the transport rate and the associated CSF secretion. However, the rate of CSF secretion could also be modulated as a secondary effect of carbonic anhydrase inhibition elsewhere in the body. An example of such AZE-mediated modulation of physiological parameters occurs in the kidney, where carbonic anhydrase-mediated HCO3− conversion is required for the reabsorption of HCO3− , which, in itself, could affect the transport rate of the choroidal HCO3− transporters supporting the CSF secretion [3−]blood modulation was, however, abolished with i.c.v. delivery of AZE or upon functional nephrectomy of the experimental rats prior to i.v. delivery of AZE, while the ICP reduction endured in both of these experimental paradigms. The ability of AZE to reduce ICP via a decrease of the rate of CSF secretion thus occurred independently of its potential effect on blood pressure and kidney function.The AZE-mediated reduction in ICP appears to be a direct result of reduced CSF secretion. Such reduction of CSF secretion can occur directly by inhibition of the carbonic anhydrases in the choroid plexus. We detected expression of the CA isoforms 2, 14, 4, 12, 11, 6, 13, 9, 5B, 3 (in order of expression level) in the rat choroid plexus (Fig. ecretion , and thu2 and thus an elevated blood pCO2. Such abrupt increase in pCO2 may cause intracranial vasodilation [2 inhalation to 30% CO2 in experimental cats [2 and the resulting ICP peak was absent in the experimental rats that had AZE administered through the i.c.v. route. The AZE-mediated elevation in blood pCO2 upon systemic application remained throughout the duration of the experiment. Organisms usually hyperventilate to correct for pCO2 elevation. Mechanical hyperventilation of the experimental rats reduced the blood pCO2 in both control rats and those exposed to AZE compared to rats with ‘normal’ ventilation parameters. Nevertheless, the AZE-induced ICP reduction remained intact – it was even slightly more pronounced. The latter finding suggests that AZE treatment in combination with the hyperventilation, sometimes employed clinically to treat elevated ICP [2-mediated reduction in cerebral blood flow [2.Administration of AZE by the i.v. route caused an initial peak in ICP prior to the subsequent gradual decline. This peak was mirrored by a decrease in the exhaled COdilation , which ctal cats . In suppated ICP , may serood flow , as it wood flow . Taken t3− transporters that are highly expressed in the choroid plexus and known to act as key contributors to CSF secretion across this tissue [In conclusion, AZE reduces the ICP in healthy rats via its ability to decrease the CSF secretion rate. AZE exerts its effect on the CSF secretion machinery in a direct manner, most likely by targeting the choroidal carbonic anhydrases. These enzymes modulate the substrate availability for the HCOs tissue , 40, 41.s tissue . HoweverAdditional file 1. Blood gas analysis and telemetric ICP measurements.


Mollaret meningitis is a recurrent aseptic meningitis mostly caused by herpes simplex virus type 2. Other causes of the disease rarely exist, and its pathology is not well understood. Herein, we present a 57-year-old man who had been admitted to our hospital eight times with recurrent aseptic meningitis. Although the deoxyribonucleic acid (DNA) of varicella-zoster virus (VZV) was not detected in the cerebrospinal fluid (CSF), his genetic analysis, measurement of anti-VZV immunoglobulin-G (IgG) in the CSF, the VZV IgG index, IgG in the serum, and interleukin-1 beta in the CSF revealed that the Mollaret meningitis had been caused by the VZV. This case demonstrates that Mollaret meningitis can be caused by the VZV when specific factors are associated with decreased immune response. This case is valuable in elucidating the pathophysiology of Mollaret meningitis. Mollaret meningitis is a recurrent aseptic meningitis (RAM), which was first reported by Mollaret in 1944 . MollareThe pathology of Mollaret meningitis is not well understood. However, in recent years, immune disorders have been reported to be associated with disease onset ,5. We re3 without malignant or Mollaret cells, 74 mg/dL protein, and 62 mg/dL glucose, and an oligoclonal band was seen. We started treatment with acyclovir, and the fever went down and the headache improved. In the follow-up CSF evaluation, the pleocytosis had improved.In November 2020, a 56-year-old man was admitted to our hospital with the eighth recurrence of aseptic meningitis. During this recurrence, neurological findings showed only meningeal signs. No obvious rash or genital herpes was observed. No markers of an inflammatory response, including serum amyloid A, were observed in the serum. The cerebrospinal fluid (CSF) contained 205 mononuclear cells/mm3 cell count at the extreme stage of recurrences, and improvements in CSF findings can be obtained along with improvements in clinical symptoms. Mollaret's cell was detected in the seventh recurrence  has been detected in the CSF to date. The patient had always visited the hospital with headache and fever for several days, and only signs of meningeal irritation were observed as physical findings. The CSF contained about 200 mononuclear cells/mme Figure . CranialDuring the seventh and eighth recurrences, anti-VZV immunoglobulin-G (IgG) (enzyme immunoassay) in the CSF increased by 0.7 and 0.9, respectively , while the VZV IgG index (CSF virus-specific IgG titer/serum titer) increased by 3.56 and 0.9, respectively   and GaldWe performed several additional analyses. Human immunodeficiency virus-1/-2 antigen and antibody screening tests were negative. The HLA haplotypes of the patient were HLA-B7 (07:02:01)/B52 (52:01:01) and HLA-DR15 (15:02:01)/DR1 (01:01:01). Correspondingly, the patient showed mildly decreased serum IgG (690 mg/dL). IL-1β was not detected in any CSF sample  inflammasome and the associated processing of proinflammatory cytokine IL-1 by activated caspase-1 in infected cells . FurtherInitially, the patient was also suspected of having Mollaret’s meningitis due to FMF. The E148Q mutation is believed to be a benign polymorphism and not a disease-causing mutation . Capron Although cases in which IL-1β was measured in the CSF of FMF patients have not been reported, IL-1β in CSF increased in patients with CNS neuropsychiatric systemic lupus erythematosus and infections of the CNS compared to healthy controls , and itsThe pathology of Mollaret meningitis, including causative microorganisms, has not been fully clarified. We consider that the dysfunction, probably due to genetic factors, of multiple immune pathways against infectious viruses affecting the CNS underlies the pathogenesis of the disease. We observe that VZV can be a pathogenic microorganism of Mollaret meningitis. We hope that the pathology of this disease will be elucidated and that appropriate treatment will be established.


With the superposition of the hierarchy, the length of the primary acicular martensite α’ phase became shorter, the width became larger, and the width of the columnar crystal β phase became smaller. The VPFP is used to change the inherent method of forming specimens with the same parameters, which provides a new idea for SLM-forming structures; the test provides data and yields a theoretical research basis for forming the specimens process method.To optimize the microstructure and properties of TC4 specimens formed by selective laser melting (SLM), the test program of formed specimens by the variable parameter forming process (VPFP) was designed based on the quantitative parameter forming process (QPFP). The purpose of this study is to explore the influence of the VPFP on the surface morphology, tensile properties, and microstructure of the specimens. The test results show that the surface morphology and tensile properties of the specimens were better formed by the VPFP. The internal holes of the specimens formed by the VPFP were small in volume and occupied a relatively small proportion, and the density could reach 99.7%. When the laser power was 300 W–260 W and equally divided into six hierarchies, the tensile strength could reach 1185.214 MPa by VPFP, but the elongation had no obvious change. The number of secondary acicular martensite  Selective laser melting (SLM) additive manufacturing technology is a discrete and stacking concept, which uses the laser beam to melt metal powder layers, manufacturing the 3D solid model layer-by-layer from bottom to top to form complex structure metal parts ,2,3. SLMCurrently, researchers have carried out relevant studies on the formation of internal defects in SLM specimens and their influence on mechanical properties. Kasperovich et al.  optimizeThe experimental research mentioned above used different methods to improve the high-quality performance of SLM-formed specimens, which greatly improved the tensile strength of the specimens. However, SLM-formed specimens usually used the same number of parameters to form the specimens. The influence of the heat transfer range of laser energy on the mechanical properties of the formed specimens was not considered during the forming process, with the increase of the height of the deposition layer. In this manuscript, the experimental specimens were equally stratified, and the parameters decreased layer-by-layer from the initial layer by the variable parameter forming process (VPFP). The specimens were formed from different bottoms to explore the differences between the specimens formed by the quantitative parameter forming process (QPFP). The microstructure and tensile strength of the specimens formed by the two processes were compared, the tensile strength of the specimens was observed, and the optimal mechanical properties were sought within a certain range of parameters. In this experiment, the thickness of the specimen was 0.9 mm, the VPFP was used to form the specimen, and six layers, at most, were used to form the thin samples by SLM. It provides a new idea for SLM forming structures and provides certain data and a theoretical research basis for a forming specimen process method.In this study, the material was Ti-6Al-4V (TC4) titanium alloy powder (prepared by gas atomization). In this study, RENISHAW AM400 a . Based on the test results, an investigation of the density, surface roughness, mechanical properties, fracture morphology, and metallographic structure of the specimens was carried out. The following major conclusions were obtained from this study:1.The density of the specimen formed by the VPFP was higher than that of the specimen formed by the QPFP. The more hierarchies of the VPFP there were, the higher the density of the specimens was. Additionally, the highest density was 99.7%. The surface roughness could be improved by using a VPFP.2.The internal holes of the specimens formed by the VPFP were small in volume and occupied a relatively small proportion, which greatly reduced the phenomenon of stress concentration and improved the mechanical properties. The tensile strength of the specimen formed by a laser power of 300 W–260 W could reach 1185.214 MPa.3.α’ phase decreased by the VPFP. With the superposition of hierarchy, the length of the primary α’ phase became shorter, the width increased, and the width of the columnar crystal β phase was smaller than that of the QPFP.The content of the secondary martensite


Hydrocephalus (HCP) is far more complicated than a simple disorder of cerebrospinal fluid (CSF) circulation. HCP is a common complication in patients with subarachnoid hemorrhage (SAH) and after craniectomy. Clinical measurement in HCP is mainly related to intracranial pressure (ICP) and cerebral blood flow. The ability to obtain quantitative variables that describe CSF dynamics at the bedside before potential shunting may support clinical intuition with a description of CSF dysfunction and differentiation between normal pressure hydrocephalus and brain atrophy. This review discusses the advanced research on HCP and how CSF is generated, stored and absorbed within the context of a mathematical model developed by Marmarou. Then, we proceed to explain the main quantification analysis of CSF dynamics using infusion techniques for deciding on definitive treatment. We consider that such descriptions of multiple parameters of measurements need to be significantly appreciated by the caring neuro-intensivist, for better understanding of the complex pathophysiology and clinical management and finally, improve of the prognosis of these patients with HCP. In this review article, we present current and novel theories of CSF circulation and pathophysiology of hydrocephalus, along with results from infusion studies for evaluating CSF dynamics at the bedside. The origin of the word hydrocephalus (HCP) is Greek and originates from the words ‘hydro’ meaning water, and ‘cephalus’ meaning head. Thus, HCP manifests with excessive cerebrospinal fluid (CSF) accumulation within the brain. Hydrocephalus is not a disease, but a pathologic state with many variations and is supposed to result from a discrepancy between CSF production and absorption. As a result, there is a subsequent accumulation of CSF in the cranial vault with an enlargement of the brain ventricles. In any case, the resulting pressure of CSF against the brain tissue is what causes HCP and for that reason the Hydrocephalus Classification Study Group has defined HCP as ‘an active distension of the ventricular system of the brain resulting from the inadequate passage of cerebrospinal fluid from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation’ –3.Nevertheless, there are conflicting data in the literature regarding mechanistic explanation of ventricular dilatation in patients suffering from subarachnoid hemorrhage (SAH) or after decompressive craniectomy . DiffereIn addition, apart from third ventriculostomy, implantation of a shunt is a standard way of managing HCP. Since shunt is a mechanistic treatment that affects patient’s pressure–volume compensation, the hydrodynamics of each patient’s compensatory reserve should be tested before a shunt is implanted. Testing CSF dynamics at the bedside, even during patient’s stay in the Intensive Care Unit (ICU), is an invasive method but may help with the decision regarding CSF diversion or cranioplasty after decompressive craniectomy .In this review, we present data from recent studies regarding novel theories of CSF circulation and pathophysiology of HCP, in patients suffering from subarachnoid hemorrhage. In addition, we provide selected forms of physiological measurements in HCP using infusion studies that were performed in the Neurocritical Care Unit at Addenbrooke’s hospital in Cambridge, UK. We think that a neuro-intensivist should be familiarized with such methods for better understanding pathophysiology of HCP, as well as for deciding proper management for each patient according to multiple forms of measurements that constitute the basics of CSF dynamics.Generally, CSF dynamics depends on interaction between four components: production, flow, absorption and pulsations.CSF is secreted by the epithelial cells of the choroid plexuses. These cells like those of other secretory epithelia are polarized in a way that the properties of their apical membrane are different from those of the basolateral membrane. Apical membrane is made up of numerous microvilli and the basolateral membrane has many infoldings, whereas both membranes have a greatly expanded area. As a result, the total area available for transport is similar to that of the blood–brain barrier. About 500 ml of CSF is produced daily and the choroid plexuses is responsible for 60–70% of CSF production. The remaining 30–40% comes from the interstitial fluid exuded from the pia from vessels. CSF physiology is based on the active formation of CSF, passive absorption and unidirectional flow of CSF from the site of formation to the place of absorption. CSF circulation is referred to as the third circulation (the other two are blood and lymph) , 9. CSF CSF circulates in a to-and-fro movement with a caudal-directed net flow through the brain ventricles to SAS, exchanging various substances. In addition, CSF circulates not only in a constant way with a rate equivalent to its production, but also in pulsations, as has been observed in the cerebral aqueduct, as well as in the cervical region of SAS , 5. SuchHowever, novel findings from different experimental studies have questioned the accuracy of Dandy’s theory  since thIn this respect and based on the theory of Klarica and colleagues , 13, theAccording to the poroelastic model , resorptPost-SAH ventricular dilatation may have a wide range of aetiological factors: starting from neuronal loss due to possible secondary ischemic insults, to obstruction of CSF circulation resulting in hydrocephalus . HydroceHCP in general is considered as a pathological state rather than a simple excessive accumulation of CSF within the ventricles and spinal canal . This paBased on the classical theory of CSF hydrodynamics, HCP may develop due to an obstruction of different circulating pathways (obstructive HCP), a reduction in its absorption from the AGs (communicating HCP) or an overproduction of CSF , 11. In Different experimental studies support the hypothesis that aqueductal narrowing or even closure occurs as a result of HCP instead of being its cause . It seemCommunicating HCP occurs very frequently and it is believed to represent an impairment of CSF absorption at the level of AGs, associated with increased resistance to CSF outflow. In such cases, all parts of the ventricular system are dilated, whereas the aqueduct of Sylvius remains patent and posteriorly expanded. In addition, alterations in the lymphatic pathway have recently been proposed as another pathophysiological mechanism of CSF absorption. Such pathway constitutes a route through the cribriform plate into the external lymphatic system located in the nasal submucosa , 14. HowA true transmantle pressure gradient can develop only in cases of total blockade of the CSF pathway between the ventricles and SAS with a simultaneous increase in CSF volume in front of the blockade. Thus, an early post-SAH HCP might be due to an abrupt blockade of the ventricular system at the level of aqueduct, probably associated with a clot formation after bleeding into the CSF. Subsequently, CSF volume continues to increase due to increased osmolarity of CSF that is associated with blood presence within CSF compartments. Increasing osmolarity leads to water influx from surrounding tissue and to an increase in CSF volume. Finally, such effects may augment ICP and give rise to a transmantle pressure gradient that induces ventricular dilatation .Different experiments using gated spin-echo MRI sequences and cine phase-contrast MRI to measure CSF hydrodynamics have shed more light into the pathophysiology of ventricular enlargement in cases of communicating HCP . In healAnother potential mechanism associated with ventricular enlargement includes CNS venous insufficiency , 25. AnyHydrocephalus after decompressive craniectomy for refractory intracranial hypertension is a common finding in patients suffering from traumatic brain injury (TBI) and SAH and raises significant diagnostic challenges to the carrying physician in the Neurocritical Care setting . Its patAccording to recent experimental data, HCP after decompressive craniectomy is usually related to: (1) reduced internal brain expansion due to the large compliant cranial defect; (2) reduced CSF pulsatile flow along major cerebral arteries and the Virchow–Robin spaces; (3) reduced clearance of the interstitial fluid by the glymphatic system and 4) redistribution of CSF from the SAS to the subdural and subgaleal compartments and the ventricles [ redistriRegarding CSF pulsatility, decompressive craniectomy creates a large low-resistance defect in the rigid cranial vault. In this case the Monro–Kellie doctrine that the sum of all contents within the skull is a fixed volume is not valid. As a result, normal brain pulsatile inward expansion is dampened and ventricular squeezing during each pulsation is diminished, giving rise to a flattened ICP waveform , 32. In The mathematical model of CSF pressure–volume compensation has been advanced by professor Marmarou who was the first who integrated all components-CSF production, circulation, absorption and storage-in one elegant theoretical structure expressed as an electric circuit , 36. ThiUnder normal conditions, production of CSF is balanced by its storage and reabsorption into the sagittal sinus (SG) according to Eq. R is the resistance to CSF outflow (units: mmHg × ml−1 × min−1) and Pss is the pressure at the level of sagittal sinus.CSF production is almost constant and is related to ICP according to Davson equation :2\documeP) and pressure in SG (PSS):Reabsorption is proportional to the gradient between CSF pressure .Storage of CSF is proportional to CSF compliance C  (units: ml−1). Elevated E (> 0.18 ml−1) signifies a poor pressure–volume compensation [C of the brain decreases, respectively.The coefficient ensation . In geneI(t) is the rate of external volume addition and Pb is the baseline pressure.Combination of Eqs. I(t). Nevertheless, the most common in clinical practice is a bolus infusion of CSF (volume ΔV), giving rise to a pressure P(t) that describes the shape of the relationship between the effective volume increase ΔV and the CSF pressure, called the pressure–volume curve). The bolus injection can be used for calculation of the so-called pressure–volume index (PVI), defined as the volume added externally to produce a tenfold increase in CSF pressure [Pp is the peak pressure recorded after addition of the volume ΔV. PVI is theoretically proportional to the inverse of brain elastance coefficient E and whenever pressure–volume compensatory reserve is insufficient, PVI is lower than 13 ml. On the contrary, a PVI higher than 26 ml signifies and over-compliant brain. Such values are valid in cases of slow infusion. However, if the bolus test is used, norms of PVI are higher  [Equation pressure , 36:7\doPractically, the bolus injection involves a fast, 2–10 s addition of 5–10 ml of Hartman solution into the CSF space. This test gives rise a value of PVI from the fast phase of rising of ICP. Resistance to CSF outflow can be calculated from the time constant of decay of the raised ICP back to baseline values.Pb, the pulse amplitude can be estimated according to Eq. Regarding AMP, if we presume that the rise in blood volume after each heart contraction is equivalent to a rapid bolus addition of CSF fluid at the baseline pressure E [In almost all cases, AMP is increased upon CSF increase by an external volume addition. The gradient of the regression line between AMP and ICP is proportional to E , 39. HowR along with other compensatory parameters in cases of HCP. Almost all researchers agree that during hydrocephalus, R is increased and CSF drainage is disturbed. The limit of normal resistance is reported to range between 13 and 18 mmHg × ml−1 × min−1.The aim of all kinds of CSF volume–pressure studies is to measure R to CSF outflow as the difference between the value of the plateau pressure during infusion and the resting pressure divided by the infusion rate. The algorithm utilizes advanced time-series analysis for volume-pressure curve retrieval, least-mean-square model fitting and an examination between AMP and ICP. Moreover, the elastance coefficient E or the PVI, cerebrospinal compliance, CSF formation rate and different indices of pressure–volume compensatory reserve are also estimated. Regarding infections rate, its incidence is less than 1% according to data from internal audit in Addenbrooke’s hospital.The computerized infusion test developed by Czosnyka , 41 is aIn this respect, the software can calculate the so-called RAP index that is the correlation coefficient between the pulse amplitude AMP and the mean value of ICP, derived by linear correlation between 40 consecutive, time averaged data points of AMP and mean ICP, acquired within a 6 s wide time window . RAP desR to CSF outflow . The RAP index is less than 0.6, reflecting low elasticity of the atrophic brain (E < 0.2 ml−1). Furthermore, B waves are rather limited during infusion studies . The elasticity is high (E > 0.20 ml−1) and RAP index is elevated more than 0.6 with an AMP higher than 4 mmHg, indicating poor compensatory reserve. Acute communicating HCP during post-SAH presents with a similar pattern of parameters, with frequent vasogenic waves [Patients suffering predominately from brain atrophy have normal CSF circulation. Typically, baseline ICP, ic waves , 46, 47.Post-craniectomy ventricular dilatation may have a wide range of etiological factors: from neuronal death due to head trauma and subsequent secondary ischemic insults to obstruction of CSF circulation resulting in HCP . It is iR to CSF outflow after craniectomy decreases twofold and brain compliance  increases substantially [R to CSF outflow × compliance of CSF space) has a tendency to remain constant. In this respect, a mechanistic increase in compliance after craniectomy tends to be followed by a decrease in R. This process might be reversed after cranioplasty, meaning a decrease in PVI might be followed by an increase in resistance to CSF outflow. According to another theory, a large craniectomy may facilitate irreversible ventricular enlargement [In addition, CSF circulation may change significantly after a cranioplasty, resulting from a previous decompressive craniectomy for refractory ICP elevation. In general, the antially . Accordiantially , time coargement . Thus, aExternal lumbar drainage (ELD) test is based on the idea of simulating the operation of the shunt by withdrawing a certain amount of CSF for long time durations, usually 48–72 h, and can be used at an inpatient setting . Tap tesIn this review, we tried to present data supporting the theory of HCP origin based on altered brain pulsatility and CSF dynamics in both post-SAH HCP and after decompressive craniectomy. In addition, it seems that physiological monitoring through infusion studies in patients developing ventricular enlargement after SAH or decompressive craniectomy can be useful in deciding if the patient is suffering from HCP, needing permanent treatment through shunting or cranioplasty, or if he is exhibiting significant brain atrophy due to secondary ischemic insults, which is resistant to CSF diversion through shunt. In any case, implementation of CSF hydrodynamic studies at the bedside may improve understanding CSF circulation, helping the carrying physician to apply more efficient and beneficial treatment for patients.


Background: Cerebrospinal fluid (CSF) rhinorrhea requires proper management to avoid disastrous consequences. The objectives of this study were to ascertain the patient characteristics, etiologies, sites of defect, skull base configurations, methods of investigation, and management outcomes of CSF rhinorrhea. Methods: A retrospective study was performed over 4 years involving three surgeons from Malaysia, Singapore, and Thailand. Hospital records were reviewed to determine the patients’ characteristics, the causes and sites of leaks, methods of investigation, skull base configurations, choices of treatment, and outcomes. Results: A total of 15 cases (7 traumatic and 8 non-traumatic) were included. Imaging was performed in all cases. The most common site of leakage was the cribriform plate (9/15 cases). The mean ± SD of the Keros heights were 4.43 ± 1.66 (right) and 4.21 ± 1.76 mm (left). Type II Keros was the most common (60%). The mean ± SD angles of the cribriform plate slope were 51.91 ± 13.43 degrees (right) and 63.54 ± 12.64 degrees (left). A class II Gera configuration was the most common (80%). All except two patients were treated with endonasal endoscopic surgical repair, with a success rate of 92.3%. A multilayered repair technique was used in all patients except one. The mean ± SD postoperative hospital stay was 9.07 ± 6.17 days. Conclusions: Non-traumatic CSF rhinorrhea outnumbered traumatic CSF rhinorrhea, with the most common site of leak at the cribriform plate. Imaging plays an important role in investigation, and Gera classification appears to be better than Keros classification for evaluating risk. Both conservative and surgical repairs are practiced with successful outcomes. Endonasal endoscopic CSF leak repair is the mainstay treatment. Disastrous consequences from ascending infection may ensue when the condition is left untreated. CSF rhinorrhea is conventionally classified into traumatic and non-traumatic causes . Under t2 ,6. Spont2 .The definitive management of CSF rhinorrhea is primarily surgery, utilizing mostly endoscopic endonasal repair techniques, with open approaches practiced in a small number of cases . ConservThe early and accurate diagnosis of a CSF leak can lead to better treatment outcomes. It can also help prevent complications. Although much has been described about the management of CSF leaks, there was a lack of information on the presentation and management of CSF rhinorrhea in Southeast Asian countries. To address this gap, the objectives of this study were to ascertain the patient characteristics, etiologies, sites of defect, skull base configurations, methods of investigation, and management outcomes of CSF rhinorrhea from three different countries in Southeast Asia, namely Malaysia, Singapore, and Thailand. The three selected countries have similar population demography, socioeconomic status, and health care systems and could reliably reflect the management practice for CSF leaks in Southeast Asian countries in general. The information obtained would be helpful to understand and improve the management of patients with CSF rhinorrhea.A retrospective study of patients with CSF rhinorrhea over 4 years from three centers in Southeast Asia was performed. In view of the retrospective case series and multicenter experience of this study, ethical approval exemption was granted by the institutions. All patients with CSF rhinorrhea and being treated at three tertiary centers in Malaysia, Thailand, and Singapore within the study period were included. The involved study groups were three surgeons from Penang General Hospital , National University Health System (Singapore), and Srinagarind Hospital (Thailand). Patients that had CSF leaks due to congenital anomalies, incomplete records, and untraceable investigations and those who were lost to follow-up were excluded.Following the review of the three hospitals’ records, a total of 15 patients fulfilled the selection criteria. Nine were males, and six were females. Of these, seven cases were traumatic (three iatrogenic and four non-iatrogenic), and eight cases were non-traumatic (where four of the eight were suspected to be due to IIH). From all the cases of spontaneous CSF rhinorrhea, 62.5% were female, and 80% of the females with spontaneous CSF rhinorrhea were attributed to IIH. The age, site of leak, anterior skull base configuration, treatment , and outcomes were recorded. Data, including the duration of the hospital stay following surgery and the duration of follow-up, were documented.p < 0.05 was considered significant.The anterior skull base was evaluated according to the Keros and Gera classifications ,11. MultThe characteristics of the patients that presented with CSF rhinorrhea are shown in Apart from the clinical assessment, the confirmation of the site of leak was mainly made by imaging. Both high-resolution CT and MRI of the paranasal sinuses and skull base were used to localize the site of leak.The use of imaging identified that the most common site of the leak was the cribriform plate (9 of 15 cases), followed by the sphenoid and frontal sinus posterior table (3 cases each). From the nine patients with identifiable defects in cribriform plate, more than half had spontaneous CSF rhinorrhea, while the rest had traumatic CSF rhinorrhea (two had iatrogenic CSF rhinorrhea and another two had non-iatrogenic CSF rhinorrhea).Intraoperative intrathecal fluorescein was employed in four cases to aid in the intraoperative localization of the site of the leak, either in cases where the site of the CSF leak was not identified pre-operatively or when there was a possibility of multiple sites, especially in the non-iatrogenic traumatic cases. Beta-2 transferrin was used in two cases that presented with intermittent leaks, where the diagnosis was in doubt.The CT scans of the 15 cases (with 30 sides) were analyzed for the height difference between the olfactory groove and the ethmoidal roof (Keros classification) . The meaFrom all studied cases, 30 sides were taken for the analysis. In total, 12 sides (40%) were type 1 Keros configurations, and 18 sides (60%) were type II Keros configurations. None of the sides had a type III Keros configuration . An analp = 0.64). While no cases in either group were Keros III, there was a significant difference in the Keros I and II classification between the traumatic and non-traumatic cases (p = 0.02). Type I Keros predominated in the traumatic cases, and type II Keros predominated in the non-traumatic cases. No significant difference was noted between the groups for the Gera classification (p = 1.00), with both having Gera II as the most common type.We subdivided the cases into traumatic and non-traumatic CSF rhinorrhea for comparison . The mosIntraoperatively, intrathecal fluorescein was used in 3 out of 13 patients to aid with the identification of the site of the CSF leak. Endonasal endoscopic surgical repair of the CSF rhinorrhea was performed in all patients except two (who were treated conservatively). The two patients that were treated conservatively had spontaneous CSF rhinorrhea . None of the patients had an open surgical repair. For all performed endonasal endoscopic surgical repairs of CSF rhinorrhea, all three surgeons shared the same technique of using multilayered repair, except in one patient . A graft was preferred for repairing the skull base defect . From the five patients that used a nasoseptal flap, four were in combination with the fat plug technique. Surgical glue was used in 9 of 13 patients (69.2%). One of the surgeons (Singapore) did not use surgical glue in four patients, with no postoperative CSF rhinorrhea reported . A lumbap = 1.00) . In one patient, a delayed leak presented a month after the first endonasal endoscopic CSF leak repair using a multilayered closure combined with a nasoseptal flap, a fat graft, and tissue glue. The second repair was performed using a similar technique with a successful outcome. There was no recurrent CSF rhinorrhea in two patients that were treated conservatively. The mean ± SD postoperative hospital stay was 9.07 ± 6.17 days (range 3–24 days). The mean ± SD follow-up duration following surgery was 5.15 ± 4.77 months (range 1–15 months). There was no significant difference in recurrent leaks between conservative management and endoscopic multilayered closure ( = 1.00) .Due to the serious potential complications of CSF rhinorrhea, it must be appropriately recognized, and the site of leak must be accurately identified for prompt management to be instituted. The leaks occur due to an abnormal connection between the subarachnoid space and a defect at skull base that leads to communication between the intracranial and sinonasal areas. The causes of CSF rhinorrhea are classified as traumatic and non-traumatic. Both types were found in our patients. Traumatic causes were recognized to be more common than the non-traumatic causes ,15. ConvIn a study involving 40 patients with CSF rhinorrhea, Sannareddy et al. observed the following characteristics. The prevalence of spontaneous CSF leaks was more common in middle-aged females, whereas post-traumatic CSF leaks were common in young adult males . TypicalInterestingly, iatrogenic trauma was more common (57%) in the traumatic group than the non-iatrogenic cause (43%). As this prevalence varies from study to study, an agreement cannot be reached on the comparison between iatrogenic and non-iatrogenic trauma ,21. Due In the traumatic group, male gender (86%) predominated compared to female gender (14%). In Southeast Asian countries, men outnumber women as the bread winners of their families, and frequently traveling to work or working on the road exposes them to a higher risk of motor vehicle accidents. In patients experiencing iatrogenic leaks, the possibility of men having an anatomical configuration at increased risk of such an occurrence cannot be excluded. A detailed assessment of the skull base anatomy, including the anterior ethmoidal roof and cribriform plate, is a pivotal critical step in the pre-operative evaluation of every patient to avert such complications.Imaging plays a key role in the accurate localization of skull base defects in patients with CSF rhinorrhea. A high-resolution CT of the brain and paranasal sinus is indispensable and represents the standard investigation to determine the site of the defect and for surgical mapping, while the additional use of MRI is valuable in spontaneous CSF rhinorrhea cases. High-resolution CT scan had sensitivity and specificity values of 92% and 100%, respectively, compared to MRI with sensitivity and specificity values of 87% and 100%, respectively, in pinpointing the skull base defect . A recomThe Keros classification of the anterior skull base is acknowledged as an important assessment, especially as a pre-operative evaluation in endoscopic sinus and skull base surgeries, where surgeons can stratify cases as low- or high-risk. A high depth of olfactory fossa (type III Keros) is conventionally associated with a greater risk of an anterior skull base traumatic CSF leak . NonetheA comprehensive review of the literature involving 1622 patients identified that the most common site of leak was the ethmoid roof (33%), followed by the cribriform plate (28%), sphenoid sinus (22%), and frontal sinus (8%) [CSF leaks are not uncommon after a base of skull fracture. Currently, there is no standardized algorithm for the investigation and management of post-traumatic CSF leaks. The diagnosis of a base of skull fracture and any resultant CSF leak can be challenging. Therefore, a combination of biochemical and radiological studies is needed to optimize the diagnosis of this condition. Post-traumatic CSF leaks are generally treated conservatively, and a majority of them resolve without further surgical management. However, for patients who are refractory to such treatments, surgical closure of the CSF fistula is necessary. The surgical obliteration of CSF leaks can be challenging and requires the involvement of multiple surgical specialties such as neurosurgery, otolaryngology, and maxillofacial surgery .Both conservative medical management and surgical repair were employed in this study with successful outcomes. The aim of conservative medical management is to decrease active flow through the leaking site, thereby reducing the CSF pressure and allowing the healing of the defect to seal the leak. These measures usually require a prolonged hospital stay to achieve the desired result. A review asserted that the overall termination of CSF leaks with conservative treatment is 39.5% at 3 days, which will improve up to 85% at 1 week or more . Two casThe modern techniques of endonasal endoscopic surgery have improved the success rate of CSF repair tremendously to over 95% ,30. SurgAll three surgeons used a similar technique of multilayered repair, except for with one patient due to surgical difficulties. However, the usage of grafts or pedicled flaps varied according to surgeons’ preferences. A wide variety of repair materials are available for the endoscopic repair of CSF leaks. Autologous fat, collagen matrix, free mucosal grafts, and tissue sealant are among the popular options, and less commonly a pedicled mucosal flap is used for postoperative persistent or recurrent leaks ,32,33,34A systematic review and meta-analysis on the outcomes of endoscopic CSF leak repair reported that the overall success rate of endonasal endoscopic CSF leak repair was 90% for primary repair and 97% for secondary repair, with a low complication rate of less than 0.03% . AnotherThe limitation of this case series was the small sample size that only represented the experience of three centers from three countries in Southeast Asia. Due to this and the retrospective nature of this study, the findings must be interpreted with caution. Further data of CSF leaks from other centers in Southeast Asian countries are required to corroborate the findings from this case series.Non-traumatic cases outnumbered traumatic CSF rhinorrhea in this case series. Both types shared a common site of leak at the cribriform plate. Imaging using CT and MRI of the brain and paranasal sinuses played an important role in confirming the CSF leak. The assessment of the anterior skull base by the Gera classification appears to be better than the Keros classification for evaluating the risk of a traumatic CSF leak. Both conservative medical treatment and endonasal endoscopic surgical repair were practiced to treat CSF rhinorrhea with successful outcomes. Endonasal endoscopic CSF leak repair is the mainstay of treatment for CSF rhinorrhea using multilayer repair techniques.