Effect of moisture content variation on dielectric properties of various plant leaves at microwave frequencies.

Complex permittivity of Corn, Jowar, Ashoka and Banana plant leaves was measured using a Vector Network Analyzer (Anritsu Shockline Model-MS46322A) over 500 MHz to 15 GHz frequency range, at different moisture contents. The dielectric constant ( ε ') and dielectric loss ( ε ″) of the leaves decrease with decrease in moisture content over this frequency range. For the leaves having moisture content less than certain critical moisture level (CML), the values of ε ' and ε " remain almost constant with frequency variation. ε ″ does not increase appreciably with the increase in moisture content up to CML. CML is found to vary for different types of leaves. At higher moisture level, ε ' and ε ″ exhibit frequency dependence. Above certain moisture level in the leaves, ε ″ starts to increase slowly with the increase in frequency above 3 GHz approaching towards the dielectric relaxation of water. The values of ε ' and ε ″ were also measured for the extract of leaves and compared with the values calculated using Stogryn equations for the same salinity, and the results agree with the calculated values. The measured values of ε ' and ε ″ for the leaves were compared with the values calculated using Debye-Cole dual dispersion dielectric model and are found to match very well.

Central Retinal Artery Occlusion in Young Adults at High Altitude: Thin Air, High Stakes.

Rana, Vipin, Pradeep Kumar, Sandeepan Bandopadhyay, Vijay K. Sharma, Meenu Dangi, Dattakiran Joshi, Sanjay Kumar Mishra, Satyabrat Srikumar, and V.A. Arun. Central retinal artery occlusion in young adults at high altitude: thin air, high stakes. High Alt Med Biol. 00:000-000, 2024.-We present five cases of young security personnel who were posted at high altitude (HA) for a duration of at least 6 months and presented with a sudden decrease of vision in one eye. The diagnosis of central retinal artery occlusion (CRAO) was made in all patients. Fundus fluorescein angiography and optical coherence tomography of the macula supported the diagnosis. None of these cases had any preexisting comorbidities. Erythrocytosis was noticed in all patients, and two of them had hyperhomocysteinemia. Four out of five patients showed either middle cerebral artery or internal carotid artery (ICA) thrombosis on computed tomography angiography. The patients were managed by a team of ophthalmologist, hematologist, vascular surgeon, and neurologist. In cases of incomplete ICA occlusion, patients were managed surgically. However, in the case of complete ICA occlusion, management was conservative with antiplatelet drugs. This case series highlights HA-associated erythrocytosis and hyperhomocysteinemia as important risk factors for CRAO in young individuals stationed at HA.

Tick hemocytes have a pleiotropic role in microbial infection and arthropod fitness.

Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here we use and develop advanced techniques to describe immune cells (hemocytes) from the clinically relevant tick Ixodes scapularis at a single-cell resolution. We observe molecular alterations in hemocytes upon feeding and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum. We reveal hemocyte clusters exhibiting defined signatures related to immunity, metabolism, and proliferation. Depletion of phagocytic hemocytes affects hemocytin and astakine levels, two I. scapularis hemocyte markers, impacting blood-feeding, molting behavior, and bacterial acquisition. Mechanistically, astakine alters hemocyte proliferation, whereas hemocytin affects the c-Jun N-terminal kinase (JNK) signaling pathway in I. scapularis. Altogether, we discover a role for tick hemocytes in immunophysiology and provide a valuable resource for comparative biology in arthropods.

A systemic approach to identify non-abundant immunogenic proteins in Lyme disease pathogens.

Borrelia burgdorferi, the pathogen of Lyme disease, differentially produces many outer surface proteins (Osp), some of which represent the most abundant membrane proteins, such as OspA, OspB, and OspC. In cultured bacteria, these proteins can account for a substantial fraction of the total cellular or membrane proteins, posing challenges to the identification and analysis of non-abundant proteins, which could serve as novel pathogen detection markers or as vaccine candidates. Herein, we introduced serial mutations to remove these abundant Osps and generated a B. burgdorferi mutant deficient in OspA, OspB, and OspC in an infectious 297-isolate background, designated as OspABC- mutant. Compared to parental isolate, the mutant did not reflect growth defects in the cultured medium but showed differential mRNA expression of representative tested genes, in addition to gross changes in cellular and membrane protein profiles. The analysis of differentially detectable protein contents of the OspABC- mutant, as compared to the wild type, by two-dimensional gel electrophoresis followed by liquid chromatography-mass spectrometry, identified several spirochete proteins that are dominated by proteins of unknown functions, as well as membrane transporters, chaperons, and metabolic enzymes. We produced recombinant forms of two of these represented proteins, BBA34 and BB0238, and showed that these proteins are detectable during spirochete infection in the tick-borne murine model of Lyme borreliosis and thus serve as potential antigenic markers of the infection.IMPORTANCEThe present manuscript employed a systemic approach to identify non-abundant proteins in cultured Borrelia burgdorferi that are otherwise masked or hidden due to the overwhelming presence of abundant Osps like OspA, OspB, and OspC. As these Osps are either absent or transiently expressed in mammals, we performed a proof-of-concept study in which their removal allowed the analysis of otherwise less abundant antigens in OspABC-deficient mutants and identified several immunogenic proteins, including BBA34 and BB0238. These antigens could serve as novel vaccine candidates and/or genetic markers of Lyme borreliosis, promoting new research in the clinical diagnosis and prevention of Lyme disease.

Polyubiquitin protein of Aedes aegypti as an interacting partner of dengue virus envelope protein.

Dengue virus (DENV) is an arbovirus that comprises four antigenically different serotypes. Aedes aegypti (Diptera: Culicidae) acts as the principal vector for DENV transmission, and vector control is crucial for dengue fever epidemic management. To design effective vector control strategies, a comprehensive understanding of the insect vector and virus interaction is required. Female Ae. aegypti ingests DENV during the acquisition of a blood meal from an infected human. DENV enters the insect midgut, replicates inside it and reaches the salivary gland for transmitting DENV to healthy humans during the subsequent feeding cycles. DENV must interact with the proteins present in the midgut and salivary glands to gain entry and accomplish successful replication and transmission. Ae. aegypti midgut cDNA library was prepared, and yeast two-hybrid screening was performed against the envelope protein domain III (EDIII) protein of DENV-2. The polyubiquitin protein was selected from the various candidate proteins for subsequent analysis. Polyubiquitin gene was amplified, and the protein was purified in a heterologous expression system for in vitro interaction studies. In vitro pull-down assay presented a clear interaction between polyubiquitin protein and EDIII. To further confirm this interaction, a dot blot assay was employed, and polyubiquitin protein was found to interact with DENV particles. Our results enable us to suggest that polyubiquitin plays an important role in DENV infection within mosquitoes.

Predicting visual outcomes following anti-vascular endothelial growth factor treatment for diabetic macular edema.

PURPOSE: To assess the utility of pre-defined imaging biomarkers on optical coherence tomography (OCT) and OCT angiography (OCTA) in patients with diabetic macular edema (DME) following anti-vascular endothelial growth factor (anti-VEGF) therapy in determining visual and anatomical outcomes. METHODS: In this prospective, non-randomized, and interventional study, 17 patients with treatment-naive DME were included. OCT biomarkers [size/reflectivity of cysts, disorganization of retinal inner layers, integrity of ellipsoid zone or external limiting membrane, subfoveal serous retinal detachment, hyper-reflective foci (HRF)] and OCTA [vascular density (VD), foveal avascular zone (FAZ), and total micro-aneurysms in superficial capillary plexus and deep capillary plexus (DCP)] were analyzed at baseline and after three monthly intravitreal anti-VEGF injections. Response was defined as a decrease of 10% or more in central macular thickness from the baseline after three injections. RESULTS: 13/17 (76.47%) patients were categorized as responders to anti-VEGF therapy. Non-responders had significantly greater hyper-reflectivity of cysts (P = 0.015), larger cystic spaces (P = 0.023), and an increased number of HRF (P = 0.04) at baseline. On OCTA, non-responders showed larger FAZ in DCP (1.35 ± 0.21 versus 1.14 ± 0.28 mm2) (P = 0.042) and lower VD (61.17 ± 0.45 versus 62.73 ± 3.32) in DCP at baseline. At 3 months, the VD increased in responders (63.10 ± 3.42) compared to a decrease in non-responders (60.82 ± 1.13) (P = 0.032). CONCLUSIONS: Non-responders show a higher number of micro-aneurysms, larger FAZ, and lower VD in the DCP on OCTA and higher cyst hyper-reflectivity and HRF and larger cystic spaces on OCT imaging.

Combat ocular trauma in counterinsurgency operations.

PURPOSE: To identify the pattern, distribution, and causes of ocular injuries among the security personnel participating in counterinsurgency operations (CIOps). METHODS: This was a multicentric, retrospective review of chart records of patients reporting to three hospitals located in the geographic region affected by CIOps. The hospital registry was examined for all patients diagnosed with any type of ocular trauma between January 1, 2016, and December 31, 2019. A standardized proforma was filled out using the case records, and entries were validated. RESULTS: A total of 131 ocular injuries fulfilled the criteria of the study. The mean age of the patients was 32.46 ± 10.2 years. All the patients were males. The causes of the injuries were explosive blasts in 60 eyes (45.80%), gunshot wounds in 15 eyes (11.42%), stone pelting in 16 eyes (12.21%), training-related causes in 26 eyes (29.84%), vehicular accidents in 13 eyes (9.92%), and battery blast in one eye (0.76%). Among the type of injuries, open globe injuries included 66 eyes (50.38%), closed globe injuries included 35 eyes (26.72%), isolated lid lacerations included 14 eyes (10.68%), and isolated chemical injury was seen in two eyes (1.52%). Optic nerve head avulsion was seen in two eyes (1.52%). CONCLUSION: The study revealed a considerable number of ocular injuries related to combat, with explosive bursts being the leading cause. The incidence of ocular injuries was found to be highest in zone 1. This study emphasizes the importance of the need for soldiers deployed in active CIOps regions to wear protective eyewear, such as ballistic goggles or military combat eye protection, to reduce the risk of ocular injuries.

A unique borrelial protein facilitates microbial immune evasion.

IMPORTANCE: Lyme disease is a major tick-borne infection caused by a bacterial pathogen called Borrelia burgdorferi, which is transmitted by ticks and affects hundreds of thousands of people every year. These bacterial pathogens are distinct from other genera of microbes because of their distinct features and ability to transmit a multi-system infection to a range of vertebrates, including humans. Progress in understanding the infection biology of Lyme disease, and thus advancements towards its prevention, are hindered by an incomplete understanding of the microbiology of B. burgdorferi, partly due to the occurrence of many unique borrelial proteins that are structurally unrelated to proteins of known functions yet are indispensable for pathogen survival. We herein report the use of diverse technologies to examine the structure and function of a unique B. burgdorferi protein, annotated as BB0238-an essential virulence determinant. We show that the protein is structurally organized into two distinct domains, is involved in multiplex protein-protein interactions, and facilitates tick-to-mouse pathogen transmission by aiding microbial evasion of early host cellular immunity. We believe that our findings will further enrich our understanding of the microbiology of B. burgdorferi, potentially impacting the future development of novel prevention strategies against a widespread tick-transmitted infection.

Tick hemocytes have pleiotropic roles in microbial infection and arthropod fitness.

Uncovering the complexity of systems in non-model organisms is critical for understanding arthropod immunology. Prior efforts have mostly focused on Dipteran insects, which only account for a subset of existing arthropod species in nature. Here, we describe immune cells or hemocytes from the clinically relevant tick Ixodes scapularis using bulk and single cell RNA sequencing combined with depletion via clodronate liposomes, RNA interference, Clustered Regularly Interspaced Short Palindromic Repeats activation (CRISPRa) and RNA-fluorescence in situ hybridization (FISH). We observe molecular alterations in hemocytes upon tick infestation of mammals and infection with either the Lyme disease spirochete Borrelia burgdorferi or the rickettsial agent Anaplasma phagocytophilum. We predict distinct hemocyte lineages and reveal clusters exhibiting defined signatures for immunity, metabolism, and proliferation during hematophagy. Furthermore, we perform a mechanistic characterization of two I. scapularis hemocyte markers: hemocytin and astakine. Depletion of phagocytic hemocytes affects hemocytin and astakine levels, which impacts blood feeding and molting behavior of ticks. Hemocytin specifically affects the c-Jun N-terminal kinase (JNK) signaling pathway, whereas astakine alters hemocyte proliferation in I. scapularis. Altogether, we uncover the heterogeneity and pleiotropic roles of hemocytes in ticks and provide a valuable resource for comparative biology in arthropods.

Retinal Manifestations in High Altitude.

Dangi, Meenu, Arnab Sadhukhan, Poninder Kumar, S. Bandopadhayay, Vijay K. Sharma, V.K. Patra, Manu Chaudhary, and Vipin Rana. Retinal manifestations in high altitude. High Alt Med Biol. 24:296-301, 2023. Aim: To study the high altitude (HA)-related retinal manifestations among security personnel and thus to provide new insights into the characteristics and mechanisms of retinopathy. Materials and Methods: This was a multicentric, nonrandomized prospective observational and descriptive study. We studied 54 security personnel over 1 year, who were referred from HA areas of northern India and north-eastern India for ocular problems. Complete coagulation profile was performed among patients with vascular occlusion. Results: There were total of 54 patients with ages ranging from 22 to 55 years. HA retinopathy was noticed in 28 patients: central retinal vein occlusion (6 patients), branch retinal vein occlusion (4 patients), branch retinal artery occlusion (1 patient), central retinal artery occlusion (4 patients), ocular ischemic syndrome (1 patient), central serous chorioretinopathy (7 patients), acetazolamide-induced maculopathy (1 patient), and solar retinopathy (2 patients). Along with an increased hematocrit, serum homocysteine was raised in the majority of vascular occlusions. The mean age was 38.16 years, the mean altitude was 14,716 ft, and the mean duration of stay was 11.2 weeks. Conclusion: Hypobaric hypoxia due to HA is a potential risk for HA retinopathy and associated vascular occlusions. Aside from increased hematocrit, hyperhomocysteinemia is a potential cause of vascular occlusions.

Hyperhomocysteinemia, High Altitude, and Varied Retinal Manifestations: Unravelling the Enigma.

Rana, Vipin, Meenu Dangi, Sandepan Bandopadhayay, Vijay K. Sharma, Satyabrat Srikumar, Jitesh Goyal, and B.V. Rao. Hyperhomocysteinemia, High Altitude, and Varied Retinal Manifestations: Unravelling the Enigma. High Alt Med Biol. 24:234-237, 2023.-We present five cases of young defense personnel, who were posted at high altitude (HA) for >6 months and presented with reduction of vision between June 2022 and February 2023. The diagnosis made were ocular ischemic syndrome, central retinal artery occlusion, central retinal vein occlusion, branch retinal vein occlusion, and branch retinal artery occlusion. There were no associated comorbidities. Hematological workup revealed increased serum homocysteine and hemoglobin in all patients. Computed tomography angiography was done in cases of ocular ischemic syndrome, and central retinal artery occlusion, which revealed occlusion of carotid artery. All patients were given tab folic acid in view of hyperhomocysteinemia (HHcy). This case series highlights that prolonged exposure to HA may lead to HHcy, which can directly or indirectly lead to various sight-threatening retinal diseases. Thus, effective preventive strategies, such as dietary or pharmacological interventions aimed at lowering serum homocysteine levels, are crucial for individuals posted at HA for longer duration.

VENOUS OVERLOAD CHOROIDOPATHY ASSOCIATED WITH IDIOPATHIC INTRACRANIAL HYPERTENSION.

PURPOSE: To report a case of venous overload choroidopathy associated with idiopathic intracranial hypertension in a 41-year-old man. METHODS: History and clinical examination, fluorescein angiography, ultra-widefield indocyanine green angiography, swept-source optical coherence tomography, and contrast-enhanced magnetic resonance imaging. RESULTS: The patient was diagnosed as having idiopathic intracranial hypertension 2 years ago, was being managed on oral acetazolamide, and retained 20/20 visual acuity in both eyes until now when he presented with a complaint of visual loss in the right eye. Ophthalmoscopy revealed serous detachment in the fovea of the right eye. Swept-source optical coherence tomography showed the presence of subretinal fluid and detachments of the retinal pigment epithelium in both eyes. Fundus fluorescein angiography showed multiple dot leaks at the level of the retinal pigment epithelium in both eyes. Indocyanine green angiography revealed vortex vein anastomoses and choroidal vascular hyperpermeability in both eyes. Contrast-enhanced magnetic resonance imaging revealed dilated optic nerve sheath diameter and a partial empty sella and magnetic resonance venography showed bilateral stenosis of the transverse sinus. CONCLUSION: Transverse sinus stenosis is a common finding in "idiopathic" intracranial hypertension and contributes to the intracranial pressure through intracranial venous hypertension. Increased venous back pressure seemed to have overloaded the choroid resulting in choroidal vascular congestion and hyperpermeability, leaks from the level of the retinal pigment epithelium, and accumulation of subretinal fluid.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Neglected Diseases.

A group of self-limiting and frequently neglected diseases exist in the literature like Rickettsial disease, Malaria, Dengue fever, Chikungunya, West Nile virus infection, Rift Valley fever, Bartonellosis, or Lyme disease which are poorly understood due to lack of proper diagnostic testing. Currently, multimodal imaging has become a critical modality in the diagnosis and management of ocular diseases. Optical coherence tomography (OCT) is one such remarkable imaging modality in the field of ophthalmology providing high-resolution, cross-sectional images of the retina and choroid with the recent advances such as enhanced depth imaging and swept source OCT. Additionally, OCT angiography (OCTA) has further revolutionised dynamic imaging of retinal and choroidal vasculature non-invasively. This review article highlights the OCT and OCTA biomarkers in the diagnosis and prognosis of the aforementioned neglected diseases.

Mucin Protein of Aedes aegypti Interacts with Dengue Virus 2 and Influences Viral Infection.

Dengue, caused by dengue virus (DENV), is the most prevalent vector-borne viral disease, posing a serious health concern to 2.5 billion people worldwide. DENV is primarily transmitted among humans by its mosquito vector Aedes aegypti; hence, the identification of a novel dengue virus receptor in mosquitoes is critical for the development of new anti-mosquito measures. In the current study, we have identified peptides which potentially interact with the surface of the virion particles and facilitate virus infection and movement during their life cycle in the mosquito vector. To identify these candidate proteins, we performed phage-display library screening against domain III of the envelope protein (EDIII), which plays an essential role during host cell receptor binding for viral entry. The mucin protein, which shared sequence similarity with the peptide identified in the screening, was cloned, expressed, and purified for in vitro interaction studies. Using in vitro pulldown and virus overlay protein-binding assay (VOPBA), we confirmed the positive interaction of mucin with purified EDIII and whole virion particles. Finally, blocking of mucin protein with anti-mucin antibodies partially reduced DENV titers in infected mosquitos. Moreover, mucin protein was found to be localized in the midgut of Ae. aegypti. IMPORTANCE Identification of interacting protein partners of DENV in the insect vector Aedes aegypti is crucial for designing vector control-based strategies and for understanding the molecular mechanism DENV uses to modulate the host, gain entry, and survive successfully. Similar proteins can be used in generating transmission-blocking vaccines.

A high-quality Ixodes scapularis genome advances tick science.

Ixodes spp. and related ticks transmit prevalent infections, although knowledge of their biology and development of anti-tick measures have been hindered by the lack of a high-quality genome. In the present study, we present the assembly of a 2.23-Gb Ixodes scapularis genome by sequencing two haplotypes within one individual, complemented by chromosome-level scaffolding and full-length RNA isoform sequencing, yielding a fully reannotated genome featuring thousands of new protein-coding genes and various RNA species. Analyses of the repetitive DNA identified transposable elements, whereas the examination of tick-associated bacterial sequences yielded an improved Rickettsia buchneri genome. We demonstrate how the Ixodes genome advances tick science by contributing to new annotations, gene models and epigenetic functions, expansion of gene families, development of in-depth proteome catalogs and deciphering of genetic variations in wild ticks. Overall, we report critical genetic resources and biological insights impacting our understanding of tick biology and future interventions against tick-transmitted infections.

Dome1-JAK-STAT signaling between parasite and host integrates vector immunity and development.

Ancestral signaling pathways serve critical roles in metazoan development, physiology, and immunity. We report an evolutionary interspecies communication pathway involving a central Ixodes scapularis tick receptor termed Dome1, which acquired a mammalian cytokine receptor motif exhibiting high affinity for interferon-gamma (IFN-γ). Host-derived IFN-γ facilitates Dome1-mediated activation of the Ixodes JAK-STAT pathway. This accelerates tick blood meal acquisition and development while upregulating antimicrobial components. The Dome1-JAK-STAT pathway, which exists in most Ixodid tick genomes, regulates the regeneration and proliferation of gut cells-including stem cells-and dictates metamorphosis through the Hedgehog and Notch-Delta networks, ultimately affecting Ixodes vectorial competence. We highlight the evolutionary dependence of I. scapularis on mammalian hosts through cross-species signaling mechanisms that dually influence arthropod immunity and development.

A 12-YEAR-OLD ASIAN INDIAN BOY WITH BILATERAL RAPIDLY PROGRESSIVE NECROTIZING MACULAR RETINITIS.

PURPOSE: To describe clinical and imaging findings in a young boy presenting with bilateral rapidly progressive necrotizing macular retinitis. METHODS: A 12-year-old Asian Indian boy developed bilateral progressive macular retinitis. He had generalized tonic-clonic seizures for the past 3 months and gave a history of poor scholastic performance with dementia of recent onset. Multimodal imaging comprising and detailed systemic and laboratory work-up was performed. RESULTS: Both eyes showed rapidly progressive full-thickness retinitis lesions observed as disruption of retinal architecture in both eyes. Left eye optical coherence tomography shows full-thickness retinal involvement with sparing of the internal limiting membrane. Electroencephalogram and magnetic resonance imaging (brain) were suggestive of subacute sclerosing panencephalitis and the diagnosis was confirmed by elevated cerebrospinal fluid and serum IgG measles. The patient did not survive despite treatment with systemic interferon therapy. CONCLUSION: It is important to look for the measles virus as a probable cause of necrotizing retinitis and neurologic symptoms in immunocompetent unvaccinated young patients. Early referral to a neurologist may assist in the early diagnosis of subacute sclerosing panencephalitis and targeted therapy.