CXCL16-dependent scavenging of oxidized lipids by islet macrophages promotes differentiation of pathogenic CD8+ T cells in diabetic autoimmunity

The pancreatic islet microenvironment is highly oxidative, rendering β cells vulnerable to autoinflammatory insults. Here, we examined the role of islet resident macrophages in the autoimmune attack that initiates type 1 diabetes. Islet macrophages highly expressed CXCL16, a chemokine and scavenger receptor for oxidized low-density lipoproteins (OxLDLs), regardless of autoimmune predisposition. Deletion of Cxcl16 in nonobese diabetic (NOD) mice suppressed the development of autoimmune diabetes. Mechanistically, Cxcl16 deficiency impaired clearance of OxLDL by islet macrophages, leading to OxLDL accumulation in pancreatic islets and a substantial reduction in intra-islet transitory (Texint) CD8+ T cells displaying proliferative and effector signatures. Texint cells were vulnerable to oxidative stress and diminished by ferroptosis; PD-1 blockade rescued this population and reversed diabetes resistance in NOD.Cxcl16-/- mice. Thus, OxLDL scavenging in pancreatic islets inadvertently promotes differentiation of pathogenic CD8+ T cells, presenting a paradigm wherein tissue homeostasis processes can facilitate autoimmune pathogenesis in predisposed individuals.

Parasite-induced IFN-γ regulates host defense via CD115 and mTOR-dependent mechanism of tissue-resident macrophage death

Host resistance to a common protozoan parasite Toxoplasma gondii relies on a coordinated immune response involving multiple cell types, including macrophages. Embryonically seeded tissue-resident macrophages (TRMs) play a critical role in maintaining tissue homeostasis, but their role in parasite clearance is poorly understood. In this study, we uncovered a crucial aspect of host defense against T. gondii mediated by TRMs. Through the use of neutralizing antibodies and conditional IFN-γ receptor-deficient mice, we demonstrated that IFN-γ directly mediated the elimination of TRMs. Mechanistically, IFN-γ stimulation in vivo rendered macrophages unresponsive to macrophage colony-stimulating factor (M-CSF) and inactivated mTOR signaling by causing the shedding of CD115 (CSFR1), the receptor for M-CSF. Further experiments revealed the essential role of macrophage IFN-γ responsiveness in host resistance to T. gondii. The elimination of peritoneal TRMs emerged as an additional host defense mechanism aimed at limiting the parasite's reservoir. The identified mechanism, involving IFN-γ-induced suppression of CD115-dependent mTOR signaling in macrophages, provides insights into the adaptation of macrophage subsets during infection and highlights a crucial aspect of host defense against intracellular pathogens.

Comparative outcome of single versus two double-pigtail stents for endoscopic drainage of pancreatic fluid collections with minimal necrosis: a retrospective analysis

Background

Endoscopic ultrasound (EUS)-guided cystogastrostomy is the treatment of choice for managing symptomatic pancreatic fluid collections (PFC). However, studies on the number of stents for optimal drainage of PFCs are limited. Hence, the present study was conducted to compare the outcome of single versus two double-pigtail stents for endoscopic drainage of PFCs.

Methods

This is a single-center, retrospective analysis of patients undergoing endoscopic drainage of PFCs with minimal necrosis (pseudocyst or walled-off necrosis with <30% solid content) at a tertiary center in South India from October 2020 to October 2022. Post-procedure, patients were followed up for clinical improvement, and stents were removed after documentation of cyst size reduction on imaging.

Results

Sixty-three patients (82.5% males, median age: 34 years) fulfilling the selection criteria were included. For single stent placement (n = 47), stents of size 8.5 Fr or 10 Fr were used, while for placement of two stents (n = 16), 7 Fr stents were used. The technical success rate was 100%. Intraprocedural and early postprocedural adverse events (all mild to moderate) were comparable between the groups (17.0% with single stent vs. 25.0% with two stents, p = NS). Clinical success was achieved in 93.6% of patients, with no difference between both groups. Three patients in the single stent group required additional procedures. All patients underwent successful stent removal after a median follow-up of 14 weeks.

Conclusion

A single pigtail stent of 8.5 Fr or 10 Fr size for EUSguided cystogastrostomy provides efficacy and safety similar to that of two stents.

In vitro-induced Foxp3+ CD8+ regulatory T cells suppress allergic IgE response in the gut

Several subsets of CD8⁺ T cells are known to have a suppressive function in different tissues and diseases in mice and humans. Due to the lack of a consensus on the phenotype of regulatory CD8⁺ T cells and very low frequency in the body, its clinical use as adoptive cellular therapy has not advanced much. In the present work, using DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (Aza), we efficiently and stably differentiated naïve CD8⁺ T cells (CD8⁺ CD25^- CD44^- cells) into the CD8⁺ Foxp3⁺ regulatory CD8⁺ T cells (CD8 Tregs). We also generated OVA peptide_257-264 -specific CD8⁺ Foxp3⁺ Tregs. Compared with activated CD8 T cells, Aza plus TGF-β-induced CD8⁺ Foxp3⁺ Tregs showed significantly increased surface expression of CD39, CD73, CD122, CD62L, and CD103, and secreted TGF-β and suppressed the proliferation of effector CD4⁺ T cells. Interestingly, CD8⁺ Foxp3⁺ Tregs exhibited low expression of perforin and granzyme required for cytotoxic function. Analysis of chemokine receptors showed that TGF-β + Aza induced CD8⁺ Foxp3⁺ Tregs expressed gut-tropic chemokine receptors CCR6 and CCR9, and chemokine receptors CCR7 and CXCR3 required for mobilization into the spleen, lymph nodes, and gut-associated lymphoid tissues. Adoptive transfer of induced CD8⁺ Foxp3⁺ Tregs restored cholera toxin-induced breakdown of oral tolerance to OVA by regulating OVA-specific IgE and IgG1. Altogether, we showed an efficient method to generate antigen-specific CD8⁺ Foxp3⁺ Tregs, and the adoptive transfer of these cells induces oral tolerance by suppressing allergic response and maintaining intestinal homeostasis.

Structural correlation to ferroelectric order, non-Griffiths like phase and magnetocaloric effect in YbCrO4

We report a ferroelectric order around ∼99 K (T_FE), which is considerably above the long range ferrimagnetic order at 25 K (T_N). The value of saturation electric polarization is considerable as ∼570μC m^-2for a poling field of 5 kV cm^-1. The ferroelectric order is associated with a significant magnetoelectric coupling below ∼90 K. A weak signature ofT_FEis observed in the dielectric constant, which is associated with a linear magnetodielectric response at 18 K(<TN). A transition to a polar structure has been correlated with the occurrence of ferroelectric order. A non-Griffiths like phase is observed around ∼48 K, which is also linked with the structural distortion. A reasonable value of the magnetic entropy change of 5.07 J Kg^-1 K^-1is noted atT_Nfor a change in field of 50 kOe, which involves a strong magnetoelastic coupling. The results indicate considerable structural instabilities, which is linked with the observed multifunctional properties of YbCrO₄.

180 NURSING HOMES DURING THE COVID-19 PANDEMIC: A NARRATIVE REVIEW OF CHALLENGES AND RESPONSES

Background

COVID-19 has caused unprecedented challenges in nursing homes. In this narrative review, we aimed to describe factors that contributed to the spread and mortality of COVID-19 in nursing homes and provide an overview of responses that were implemented to try to overcome such challenges.

Methods

The MeSH terms ‘Nursing homes’ and ‘COVID-19’ were searched in MEDLINE Ovid, and English language articles were retrieved that were published between 1 March 2020 and 31 January 2021. Article titles and abstracts were screened by two reviewers, and the results of included articles were grouped by themes.

Results

The search retrieved 348 articles, of which 76 were included in the thematic review. 8 articles related to COVID-19 disease characteristics (e.g. asymptomatic transmission), 24 to resident-related factors (e.g. comorbidities, nutrition, cognition), 13 to facility characteristics (e.g. physical space, occupancy, for-profit status), 21 to staffing (e.g. staffing levels, staff-to-resident ratio, staff multi-employment), and 10 to external factors (e.g. availability of personal protective equipment, prevailing health and social care policies). In terms of responses, identified themes included widespread testing, isolation and cohorting of residents, staff protection and support, promotion of residents’ well-being, and technological innovations.

Conclusion

COVID-19 exerted severe challenges on the nursing home population and its staff. Both internal and external factors predisposed nursing homes to an increased propensity of spread. Numerous strategies were employed to attempt to mitigate the negative impacts. Substantial learning occurred that may not only aid future pandemic preparedness but improve quality of care for nursing home residents at all times.

IFN-γ mediates Paneth cell death via suppression of mTOR

Paneth cells constitutively produce antimicrobial peptides and growth factors that allow for intestinal homeostasis, host protection, and intestinal stem cell replication. Paneth cells rely heavily on the glycolytic metabolic program, which is in part controlled by the kinase complex Mechanistic target of rapamycin (mTORC1). Yet, little is known about mTOR importance in Paneth cell integrity under steady-state and inflammatory conditions. Our results demonstrate that IFN-γ, a crucial mediator of the intestinal inflammation, acts directly on murine Paneth cells to alter their mitochondrial integrity and membrane potential, resulting in an TORC1-dependent cell death mechanism distinct from canonical cell death pathways including apoptosis, necroptosis, and pyroptosis. These results were established with the purified cytokine and a physiologically relevant common Th1-inducing human parasite Toxoplasma gondii. Given the crucial role for IFN-γ, which is a cytokine frequently associated with the development of inflammatory bowel disease and compromised Paneth cell functions, the identified mechanisms underlying mTORC1-dependent Paneth cell death downstream of IFN-γ may provide promising novel approaches for treating intestinal inflammation.

Use of personal protective equipment among waste workers of Sisdol landfill site of Nepal

Introduction: Solid waste management is a major issue in Nepal with Kathmandu valley generating the highest amount of solid waste. After recovery, the solid waste generated in Kathmandu valley is transferred to the Sisdol landfill site. There are waste workers in Sisdol landfill site who sustain their livelihood by collecting recyclables from those wastes. Personal protective equipment (PPE) is necessary to protect the frontline waste workers against infection. In addition, the waste workers need to know the proper usage of PPE in order to protect themselves from contamination. This study aimed to assess the awareness and proper usage of PPE along with the challenges faced by the waste workers at Sisdol landfill site. Methods: A descriptive cross-sectional study was conducted to collect data from landfill waste workers of Sisdol located at Kakani Rural Municipality in Nuwakot district of Nepal. A convenience sampling method was used based on the availability of landfill waste workers on that day and their willingness to participate. The data was collected using the structured questionnaire and personal interview of available waste workers. Results: The study comprised of 65% female and 35% male waste workers. The highest percentage of waste workers belong to 27-37 age group occupying 43% of total respondents.  Around 92% waste workers had participated in any orientation/training or session related to PPE and its usage. About 60% landfill waste workers were found only using mask and gloves. Conclusion: There is small number of waste workers who wish to wear full set of PPE. Most of them only like to wear mask and gloves. The gender, age group and the education level of waste workers had no association with the usage of PPE during the work.

Differentiation and functional plasticity of gamma-delta (γδ) T cells under homeostatic and disease conditions

Gamma-delta (γδ) T cells are a heterogeneous population of immune cells, which constitute <5% of total T cells in mice lymphoid tissue and human peripheral blood. However, they comprise a higher proportion of T cells in the epithelial and mucosal barrier, where they perform immune functions, help in tissue repair, and maintaining homeostasis. These tissues resident γδ T cells possess properties of innate and adaptive immune cells which enables them to perform a variety of functions during homeostasis and disease. Emerging data suggest the involvement of γδ T cells during transplant rejection and survival. Interestingly, several functions of γδ T cells can be modulated through their interaction with other immune cells. This review provides an overview of development, differentiation plasticity into regulatory and effector phenotypes of γδ T cells during homeostasis and various diseases.

Vγ2+ gamma-delta (γδ) T cells promotes the survival of skin allografts in the presence of anti-CD40L induced transplantation tolerance

Donor-specific transfusion (DST) and anti-CD40L treatment is one of the best tolerogenic strategies for promoting the survival of allografts. The effect of DST and anti-CD40L treatment on the phenotype and function of most of the innate and adaptive immune cells are known. Gamma delta (γδ) T cells uniquely possess features of both innate and adaptive immune cells and perform crucial functions during cancer and autoimmune diseases. Recent reports have suggested that γδ T cells promote skin allograft rejection but their contribution during costimulatory blockade induced skin allograft survival is not known. In the present study, we show that depletion of γδ T cells or specifically Vδ2+ γδ T cells led to acute rejection of skin allografts even with DST and anti-CD40L mAb treatment. Tolerogen treatment increased the expression of regulatory receptor CD39 on Vδ2+ γδ T cells. Tolerogen treatment reduced IFN-γ expression in Vγ2+ γδ T cells which in-turn suppressed the Th1 differentiation of naive CD4+T cells. Depletion of Vγ2+ γδ T cells induced hyper IFN-γ response in tolerogen-treated allograft recipients. Tolerogen-treated and Vγ2+ γδ T cells-depleted recipients showed enhanced infiltration of activated macrophages in the skin allografts. Adoptive transfer of Vγ2+ γδ T cells purified from tolerized mice in naive mice promoted the survival of skin allografts. Taken together, our results showed that Vγ2+ γδ subset of T cells promote costimulatory blockade-induced prolonged survival of allografts and suggest its importance in adoptive cellular therapy to control the allograft rejection.

Significant magneto-elastic coupling at Griffiths-like phase boundaries in low dimensional oxides,ASb2O6(ANi and Mn)

The compounds, NiSb₂O₆(NSO) and MnSb₂O₆(MSO) attract the community for the quasi one-dimensional and layered structure composed of Ni²⁺and Mn²⁺, which orders antiferromagnetically atT_N= 6.7 and 12 K, respectively. Here, we report the Griffiths-like phase much aboveT_Nin the range of 37-85 K and 25-80 K for NSO and MSO, respectively. The dc magnetization results indicate the Griffiths-like phase, following the modified Curie-Weiss law. The magneto-capacitive responses for both the compounds show anomalies at the onset of the Griffiths-like phase. Intriguingly, the low temperature synchrotron diffraction results are conclusive for determining the singularities for both the compounds. Interplay between the low-dimensionality, magnetic frustration, and magneto-elastic coupling correlates the observed short range ordered state, which is suggested as a Griffiths-like phase, aboveT_Nfor both the compounds.

Interplay between positive magnetoresistance and thermoelectric properties by tuning carrier concentration in Sb2-xSnxTe3(x⩽ 0.05) crystals

We report transport properties of Sb2-xSnxTe3(x⩽ 0.05) single crystals, where the tuning of the charge carrier densities via Sn doping significantly improves the magnetoresistance (MR) and the thermoelectric (TE) properties. The MR increases significantly at 2 K forx= 0.01, which reduces considerably with further Sn doping atx= 0.05. The MR results below 90 K forx= 0.01 satisfy the semi-classical two-band approach of Kohler's rule, which does not satisfy the MR results forx= 0.05. At 300 K, the Seebeck coefficient (S) is positive and small forx= 0.01 and it changes the sign with the further increase in Sn doping atx= 0.05 at 300 K. The value of |S| is considerable with an enhancement of the thermoelectric power factor compared to the value forx= 0.01 at 300 K. Analysis of the Hall conductivity indicates the interplay between carrier mobilities and densities, leading to the tuning of MR and TE properties with Sn doping. These results demonstrate that the p-type Sb2Te3becomes n-type with a suitable doping engineering.

Dynamic regulation of chromatin organizer SATB1 via TCR-induced alternative promoter switch during T-cell development

The chromatin organizer SATB1 is highly enriched in thymocytes and is essential for T-cell development. Although SATB1 regulates a large number of genes important for T-cell development, the mechanism(s) regulating expression of SATB1 during this process remain elusive. Using chromatin immune precipitation-seq-based occupancy profiles of H3K4me3 and H3Kme1 at Satb1 gene locus, we predicted four different alternative promoters of Satb1 in mouse thymocytes and characterized them. The expression of Satb1 transcript variants with distinct 5′ UTRs occurs in a stage-specific manner during T-cell development and is dependent on TCR signaling. The observed discrepancy between the expression levels of SATB1 mRNA and protein in developing thymocytes can be explained by the differential translatability of Satb1 transcript variants as confirmed by polysome profiling and in vitro translation assay. We show that Satb1 alternative promoters exhibit lineage-specific chromatin accessibility during T-cell development from progenitors. Furthermore, TCF1 regulates the Satb1 P2 promoter switch during CD4SP development, via direct binding to the Satb1 P2 promoter. CD4SP T cells from TCF1 KO mice exhibit downregulation of P2 transcript variant expression as well as low levels of SATB1 protein. Collectively, these results provide unequivocal evidence toward alternative promoter switch-mediated developmental stage-specific regulation of SATB1 in thymocytes.

Unveiling spin-glass transition and antiferromagnetic order by μSR studies in spin-chain Sm2BaNiO5

We report the zero-field and longitudinal field muon spin relaxation studies in a spin-chain compound Sm₂BaNiO₅. Two magnetic transitions, that have not been previously detected by the heat capacity and magnetization measurements, are confirmed at 46 and 9 K. The antiferromagnetic order is suggested at 46 K. Analysis of the muon spin polarization unveils the spin-glass transition at 9 K. Time-field scaling relation of the muon spin polarization verifies the spin-spin autocorrelation function following the cut-off power law, which is approximated by the Ogielski form, as employed numerically for characterizing the spin-glasses.

Coexisting exchange bias effect and ferroelectricity in geometrically frustrated ZnCr2O4

Concomitant occurrence of exchange bias effect and ferroelectric order is revealed in antiferromagnetic spinel ZnCr₂O₄. The exchange bias effect is observed below antiferromagnetic Neél temperature (T _N) with a reasonable value of exchange bias field ([Formula: see text] Oe at 2 K). Intriguingly, the [Formula: see text] ratio is found unusually high as  ∼2.2, where H _C is the coercivity. This indicates that large H _C is not always primary for obtaining large exchange bias effect. Ferroelectric order is observed at T _N, where non-centrosymmetric magnetic structure with [Formula: see text] space group associated with the magnetoelectric coupling correlates the ferroelectric order, proposing that, ZnCr₂O₄ is an improper multiferroic material. Rare occurrence of exchange bias effect and ferroelectric order in ZnCr₂O₄ attracts the community for fundamental interest and draws special attention in designing new materials for possible electric field control of exchange bias effect.

Observation of short range order driven large refrigerant capacity in chemically disordered single phase compound Dy2Ni0.87Si2.95

In this work, we report the successful synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 forming in single phase only with a chemically disordered structure. The random distribution of Ni/Si and crystal defects create a variation in the local electronic environment between the magnetic Dy ions. In the presence of both disorder and competing exchange interactions driven magnetic frustration, originating due to c/a ∼ 1, the compound undergoes spin freezing behaviour below 5.6 K. In the non-equilibrium state below the spin freezing behaviour, the compound exhibits aging phenomena and magnetic memory effects. In the magnetically short-range ordered region, much above the freezing temperature, an unusual occurrence of considerable magnetic entropy change, -ΔSmaxM ∼ 21 J kg-1 K-1 with large cooling power RCP ∼ 531 J kg-1 and adiabatic temperature change, ΔTad ∼ 10 K for a field change of 70 kOe, is observed for this short range ordered cluster-glass compound without any magnetic hysteresis loss.

Chemical disorder driven reentrant spin cluster glass state formation and associated magnetocaloric properties of Nd2Ni0.94Si2.94

In this work, we report the synthesis of a new ternary intermetallic compound, Nd₂Ni_0.94Si_2.94, that forms in single phase only in a defect crystal structure. The compound exhibits an antiferromagnetic transition below 7.2 K (T_N) followed by a spin cluster freezing behaviour below 2.85 K (T_f), which makes the compound a reentrant spin cluster glass system. The detailed studies of dc and ac magnetization, heat capacity, non-equilibrium dynamical behaviour, viz., aging effect, temperature and field dependent magnetic relaxation and magnetic memory effect establish the compound to be a cluster-glass material below freezing temperature. The interplay between competing exchange coupling (c/a ≃ 1.04 ⇒ J_NN ≃ J_NNN) and chemical disorder driven variation in the electronic environment among the Nd ions has been argued to be responsible for such a metastable state formation. A considerable value of MCE parameters (-ΔS ∼ 11.4 J kg^-1 K^-1, RCP ∼ 160 J kg^-1 and ΔT_ad ∼ 5.2 K for a field change of 70 kOe) is obtained for this magnetically frustrated glassy compound.

Initial experience with a dual-console robotic-assisted platform for training in colorectal surgery

BACKGROUND

Minimally invasive surgery is associated with several patient-related benefits, including reduced length of hospital stay and reduced blood loss. Robotic-assisted surgery offers many advantages when compared with standard laparoscopic procedures, including a stable three-dimensional binocular camera platform, motion smoothing and motion scaling, improved dexterity and ergonomics. There are limited data on the effectiveness of the dual-console DaVinci Xi platform for teaching resident surgeons. The goal of this study was to examine preliminary outcomes following the introduction of a dual-console robotic platform in our institution.

METHODS

A retrospective review of our prospectively maintained patient database was performed. The first ten dual-console resident-performed procedures in colorectal surgery were compared with matched cases performed on a single console by the trainer. Patient demographics, operative times and patient outcomes were compared.

RESULTS

Twenty patients were included in this study. There was no significant difference in console time (p = 0.46) or total operative time (p = 0.52) when residents and trainers were compared. Patient outcomes were equivalent, with no difference in length of stay, morbidity or mortality.

CONCLUSIONS

The DaVinci Xi dual-console platform is a safe and effective platform for training junior surgeons. The dual-console system has the potential to alter surgical training pathways.

Observation of ultrasharp metamagnetic jumps in polycrystalline Er2Cu2O5

The observation of ultrasharp metamagnetic jumps in the field variation of magnetization (M versus H) data for the highly insulating metal oxide Er₂Cu₂O₅ is investigated. The compound orders antiferromagnetically below about T _N1  =  28 K and shows conventional 'not-so-sharp' metamagnetism around 13 kOe on the field-increasing leg in the polycrystalline sample. The uniqueness of the ultrasharp jumps in Er₂Cu₂O₅ resides in the fact that they are only observed in the field-decreasing segment of the magnetization curve. We observe that the jumps are affected by the sweep rate of the magnetic field, similarly to several other systems that show such ultrasharp jumps. Er₂Cu₂O₅ shows a considerable amount of thermo-remanent magnetization when it is cooled in a field that is higher than the critical field of 13 kOe. Our analysis indicates that above 13 kOe the system remains phase separated, with the coexistence of antiferromagnetic and field-induced ferromagnetic-like phases. The jumps in the return leg occur because of the shear-dominated martensitic-like phase transition of the ferromagnetic-like phase to an antiferromagnetic phase, and interfacial strain plays a major role in the observed jumps.

Hypopituitarism presenting as congestive heart failure

Sheehan's syndrome (SS) develops as a result of ischemic pituitary necrosis due to severe postpartum hemorrhage and is characterized by various degrees of hypopituitarism. Although the occurrence of SS is now rare, it should still be considered in any woman with a history of peripartum hemorrhage who develops manifestations of pituitary hormone deficiency any time following the event. Appropriate hormone replacement therapy results in marked clinical improvement. We present an unusual case of SS in a young lady who continued to have normal menstruation after the index event, had two spontaneous pregnancies, and was diagnosed only 11 years later when she presented to us with acute heart failure.