Publications by authors named "Tanya Leroith"

Article Synopsis
  • Oral antibiotic use in older adults can disrupt gut microbiota, leading to health issues like infections and chronic diseases.
  • A study involving mice showed that those on a high glycemic diet with antibiotics had significantly lower survival rates due to severe gut damage, unlike those on a low glycemic diet.
  • The low glycemic diet helped maintain a healthier gut microbiome and preserved important bacterial functions, suggesting it could be a helpful strategy to prevent gut issues caused by antibiotics.
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Background: Multiple studies have demonstrated associations between the early-life gut microbiome and incidence of inflammatory and autoimmune disease in childhood. Although microbial colonization is necessary for proper immune education, it is not well understood at a mechanistic level how specific communities of bacteria promote immune maturation or drive immune dysfunction in infancy.

Objectives: In this study, we aimed to assess whether infant microbial communities with different overall structures differentially influence immune and gastrointestinal development in healthy mice.

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Unlabelled: Maternal secretor status is one of the determinants of human milk oligosaccharides (HMOs) composition, which, in turn, influences the gut microbiota composition of infants. To understand if this change in gut microbiota impacts immune cell composition, intestinal morphology, and gene expression, 21-day-old germ-free C57BL/6 mice were transplanted with fecal microbiota from infants whose mothers were either secretors (SMM) or non-secretors (NSM) or from infants consuming dairy-based formula (MFM). For each group, one set of mice was supplemented with HMOs.

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Introduction: Colonocyte oxidation of bacterial-derived butyrate has been reported to maintain synergistic obligate anaerobe populations by reducing colonocyte oxygen levels; however, it is not known whether this process is disrupted during the progression of type 2 diabetes. Our aim was to determine whether diabetes influences colonocyte oxygen levels in the University of California Davis type 2 diabetes mellitus (UCD-T2DM) rat model.

Research Design And Methods: Age-matched male UCD-T2DM rats (174±4 days) prior to the onset of diabetes (PD, n=15), within 1 month post-onset (RD, n=12), and 3 months post-onset (D3M, n=12) were included in this study.

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An 11-year-old, intact female Pomeranian dog was presented for evaluation due to an 18-h history of anorexia and lethargy. Abdominal ultrasound revealed a 3×3 cm mass of mixed echogenicity at the level of the left ovary. At laparotomy, a 5 mm mass was identified at the cranial region of the right uterine horn and a 3 cm round mass was visualized near the cranial aspect of the left uterine horn.

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SARS-CoV-2 is primarily transmitted through droplets and airborne aerosols, and in order to prevent infection and reduce viral spread vaccines should elicit protective immunity in the airways. The neonatal Fc receptor (FcRn) transfers IgG across epithelial barriers and can enhance mucosal delivery of antigens. Here we explore FcRn-mediated respiratory delivery of SARS-CoV-2 spike (S).

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Systemic lupus erythematosus (SLE) is an autoimmune disease caused by environmental factors and loss of key proteins, including the endonuclease Dnase1L3. Dnase1L3 absence causes pediatric-onset lupus in humans, while reduced activity occurs in adult-onset SLE. The amount of Dnase1L3 that prevents lupus remains unknown.

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Canine soft tissue sarcomas (STS) are common neoplasms and considered immune deserts. Tumour infiltrating lymphocytes are sparse in STS and, when present, tend to organize around blood vessels or at the periphery of the neoplasm. This pattern is associated with an immunosuppressive tumour microenvironment linked to overexpression of molecules of the PD-axis.

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Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease caused by environmental factors and loss of key proteins. One such protein is a serum endonuclease secreted by macrophages and dendritic cells, Dnase1L3. Loss of Dnase1L3 causes pediatric-onset lupus in humans is Dnase1L3.

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Article Synopsis
  • The study focuses on how the Mayaro virus (MAYV) adapts to urban mosquito vectors like Ae. aegypti, which could influence its transmission and emergence as a health threat.
  • Researchers discovered a specific mutation (E2-T179N) that enhances MAYV replication in mosquitoes, improving its transmission after passing through the mosquito's gut, but it reduces its ability to replicate in human cells.
  • The findings suggest that while this mutation may increase the virus's ability to spread through mosquitoes, it compromises its efficiency in human hosts, indicating a complex trade-off in virus adaptation that might lead to future emergence of outbreaks.
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Article Synopsis
  • Hepatitis E virus (HEV) infection during pregnancy leads to significant fetal loss in pregnant rabbits, with a notable 23% rate of early-stage miscarriages observed.
  • The infection results in higher viral loads and altered immune responses in pregnant rabbits compared to nonpregnant ones, indicating a more severe impact on the health and immune function of the pregnant hosts.
  • Elevated levels of the hormone estradiol were found in infected pregnant rabbits, suggesting a potential link between hormone levels and increased viral replication, which may contribute to adverse pregnancy outcomes.
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Chronic hepatitis E virus (HEV) infection has become a significant clinical problem that requires treatment in immunocompromised individuals. In the absence of an HEV-specific antiviral, ribavirin (RBV) has been used off-label, but treatment failure may occur due to mutations in the viral RNA-dependent RNA polymerase (RdRp), including Y1320H, K1383N, and G1634R. Chronic hepatitis E is mostly caused by zoonotic genotype 3 HEV (HEV-3), and HEV variants from rabbits (HEV-3ra) are closely related to human HEV-3.

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Melanomas in humans and dogs are highly malignant and resistant to therapy. Since the first development of immunotherapies, interest in how the immune system interacts within the tumor microenvironment and plays a role in tumor development, progression, or remission has increased. Of major importance are tumor-infiltrating lymphocytes (TILs) where distribution and cell frequencies correlate with survival and therapeutic outcomes.

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A controlled-neonatal piglet trial was conducted to evaluate the impact of a plant-based infant formula containing buckwheat and almonds as the main source of protein compared to a commercially available dairy-based formula on the gut health parameters. Two day old piglets were fed either a plant-based or a dairy-based formula until day 21. Gut microbiome, cytokines, growth and metabolism related outcomes, and intestinal morphology were evaluated to determine the safety of the plant-based infant formula.

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The hepatitis B virus core antigen (HBcAg) tolerates insertion of foreign epitopes and maintains its ability to self-assemble into virus-like particles (VLPs). We constructed a ∆HBcAg-based VLP vaccine expressing three predicted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B and T cell epitopes and determined its immunogenicity and protective efficacy. The recombinant ∆HBcAg-SARS-CoV-2 protein was expressed in Escherichia coli, purified, and shown to form VLPs.

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A 6 yr old male castrated American Staffordshire terrier was referred for a nonhealing wound at the site of a previously incompletely excised, high-grade soft tissue sarcoma. Physical examination revealed right popliteal lymphadenopathy and a fungating mass of the right pelvic limb at the level of the hock. Thoracic and abdominal computed tomography revealed mild lymphadenopathy of multiple iliac and inguinal lymph nodes.

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SARS-CoV-2 and its variants cause COVID-19, which is primarily transmitted through droplets and airborne aerosols. To prevent viral infection and reduce viral spread, vaccine strategies must elicit protective immunity in the airways. FcRn transfers IgG across epithelial barriers; we explore FcRn-mediated respiratory delivery of SARS-CoV-2 spike (S).

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Usutu virus (USUV, ) is an emerging mosquito-borne virus that has been implicated in neuroinvasive disease in humans and epizootic deaths in wild birds. USUV is maintained in an enzootic cycle between ornithophilic mosquitoes, primarily spp., and wild birds, predominantly passerine species.

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Systemic lupus erythematosus (SLE) is a complex autoimmune disease that has a strong preference for women of child-bearing age. Maternal factors play an essential role in shaping the immune system of the newborn, yet it is unknown whether maternal factors could modulate the development of SLE in the offspring. Activation-induced cytidine deaminase (AID) is an enzyme required for somatic hypermutation and class switch recombination.

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Article Synopsis
  • Human milk oligosaccharides (HMOs) are a key component of human milk, influencing gut health and immune response, but their direct effects on intestinal function are still not fully understood.
  • In a study, germ-free mice were given HMOs and analyzed for intestinal changes and immune cell responses during various stages post-treatment.
  • The findings revealed significant alterations in gut structure and gene expression due to HMOs, along with changes in immune cell populations, indicating that HMOs have a specific impact on intestinal health and immunity.
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Hepatitis E virus (HEV) is an important but understudied zoonotic virus causing both acute and chronic viral hepatitis. A proportion of HEV-infected individuals also developed neurological diseases such as Guillain-Barré syndrome, neuralgic amyotrophy, encephalitis, and myelitis, although the mechanism remains unknown. In this study, by using an in vitro blood-brain barrier (BBB) model, we first investigated whether HEV can cross the BBB and whether the quasi-enveloped HEV virions are more permissible to the BBB than the nonenveloped virions.

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Deterioration in glucose homeostasis has been associated with intestinal dysbiosis, but it is not known how metabolic dysregulation alters the gastrointestinal environment. We investigated how the progression of diabetes alters ileal and colonic epithelial mucosal structure, microbial abundance, and transcript expression in the University of California Davis Type 2 Diabetes Mellitus (UCD-T2DM) rat model. Male UCD-T2DM rats (age ~170 days) were included if <1-month (n = 6, D1M) or 3-month (n = 6, D3M) post-onset of diabetes.

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Equine protozoal myeloencephalitis (EPM) is a debilitating neurologic disease affecting horses across the Americas. Gaps in understanding the inflammatory immune response in EPM-affected horses create difficulties with diagnosis and treatment, subsequently negatively impacting the prognosis of affected horses. The purpose of the current study was to evaluate circulating levels of the inflammatory immune marker soluble CD14 (sCD14), in horses with EPM (n = 7) and determine if they differed from healthy neurologically normal horses (n = 6).

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Article Synopsis
  • The COVID-19 pandemic has greatly affected the world, causing many deaths and making people with health issues like obesity more at risk for serious illness.
  • In a study, scientists looked at how obesity impacts the severity of COVID-19 in mice that were made obese through their diet.
  • They found no big differences in lung damage or virus levels between the obese and lean mice, but certain immune responses were stronger in the obese mice, and the obese mice lost weight from the treatment used in the study.
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