Toward the Scalable, Rapid, Reproducible, and Cost-Effective Synthesis of Personalized Nanomedicines at the Point of Care.

Organic nanoparticles are used in nanomedicine, including for cancer treatment and some types of COVID-19 vaccines. Here, we demonstrate the scalable, rapid, reproducible, and cost-effective synthesis of three model organic nanoparticle formulations relevant to nanomedicine applications. We employed a custom-made, low-cost fluid mixer device constructed from a commercially available three-dimensional printer. We investigated how systematically changing aqueous and organic volumetric flow rate ratios determined liposome, polymer nanoparticle, and solid lipid nanoparticle sizes, size distributions, and payload encapsulation efficiencies. By manipulating inlet volumes, we synthesized organic nanoparticles with encapsulation efficiencies approaching 100% for RNA-based payloads. The synthesized organic nanoparticles were safe and effective at the cell culture level, as demonstrated by various assays. Such cost-effective synthesis approaches could potentially increase the accessibility to clinically relevant organic nanoparticle formulations for personalized nanomedicine applications at the point of care, especially in nonhospital and low-resource settings.

Respiratory compromise in French bulldogs presented with intervertebral disc extrusion.

BACKGROUND: French bulldogs hospitalised for the management of intervertebral disc extrusion (IVDE) are frequently affected by respiratory compromise, typically brachycephalic-associated upper respiratory obstruction and/or aspiration events. We evaluated the occurrence of such respiratory compromise events in French bulldogs presented to two referral hospitals. METHODS: Clinical data for French bulldogs diagnosed with IVDE were retrospectively collated, including severity of neurological deficits, neuroanatomical localisation, diagnosis, details of respiratory compromise, treatment and outcome. RESULTS: A total of 306 dogs diagnosed with IVDE were included. Sixty dogs (19.6%) experienced respiratory compromise, of which 31 dogs (10.1%) progressed to cyanosis, collapse or respiratory arrest. LIMITATIONS: The study was limited by its retrospective nature. Furthermore, the duration of hospitalisation was not evaluated and the decision for euthanasia was often multifactorial. CONCLUSION: One in five French bulldogs presented with IVDE experienced respiratory compromise. The detrimental welfare effects of this warrant further discussion.

Bacterial meningitis secondary to otogenic infection in 10 French bulldogs: A retrospective case series.

Background: There is limited published information to guide the clinical management of bacterial meningitis/encephalitis in dogs. Methods: This was a retrospective case series comprising 10 French bulldogs from two referral centres. The cases were diagnosed with bacterial meningitis/encephalitis suspected secondary to otogenic infection based on detection of abnormal fluid/soft tissue opacity within the middle/inner ear, associated meningeal/intracranial involvement through MRI, the findings of cerebro-spinal fluid (CSF) analysis suggestive of sepsis and/or clinical improvement following antibiosis. Results: Ten dogs were included (three female and seven male), with a median age of 60 months. Dogs presented with acute onset (median 2 days), progressive history of vestibular signs and/or intra-oral or cervical pain. Five dogs had gross signs of concurrent otitis externa. Common MRI findings included material within the tympanic bulla with adjacent meningeal enhancement. Analysis of CSF documented pleocytosis in all eight dogs, intracellular bacteria seen in three with positive bacteriological culture in two dogs. One dog was euthanised following diagnosis. Nine remaining dogs received antimicrobial therapy and six underwent surgical management. Three dogs treated surgically were neurologically normal within 2 weeks and the remaining three improved. Two dogs treated medically improved and one had complete resolution reported within a 4-week follow-up period. Study limitations include its retrospective nature and small sample size with minimal longer term follow-up. Conclusions: Bacterial meningitis/encephalitis in French bulldogs can require both medical and surgical treatment to achieve a favourable outcome.

Non-traumatic hemorrhagic myelopathy in dogs.

BACKGROUND: Non-traumatic spinal cord hemorrhage (NTSH) is an uncommon cause of myelopathy in dogs. OBJECTIVES: Describe the clinical characteristics, concurrent medical conditions and underlying causes, magnetic resonance imaging (MRI) findings and outcome in dogs with NTSH. ANIMALS: Dogs diagnosed with NTSH using gradient echo T2-weighted (GRE) sequences with or without histopathological confirmation of hemorrhage were included. Dogs with a traumatic cause were excluded, including those with compressive intervertebral disc extrusion. METHODS: Retrospective descriptive study; the databases of 2 referral hospitals were searched between 2013 and 2021. RESULTS: Twenty-three dogs met inclusion criteria. The onset of signs was acute and progressive in 70% of cases; spinal hyperesthesia was variable (48%). Hemorrhage was identified in the thoracolumbar spinal segments in 65% of dogs. An underlying cause was identified in 65% of cases. Angiostrongylus vasorum represented 18% of the total cohort, followed by steroid-responsive meningitis arteritis (SRMA; 13%). Overall, 64% of dogs had a good or excellent outcome, regardless of cause; which was increased to 100% for SRMA, 75% for A. vasorum and 75% for idiopathic NTSH. Outcome was not associated with neurological severity. Recovery rate was 67% and 50% for nociception-intact and nociception-negative dogs, respectively. CONCLUSIONS: Larger prospective studies would be required to define prognostic factors for dogs with NTSH, but outcome appeared to be most influenced by the underlying cause, as opposed to neurological severity at presentation.

Controlling Nanoparticle Uptake in Innate Immune Cells with Heparosan Polysaccharides.

We used heparosan (HEP) polysaccharides for controlling nanoparticle delivery to innate immune cells. Our results show that HEP-coated nanoparticles were endocytosed in a time-dependent manner by innate immune cells via both clathrin-mediated and macropinocytosis pathways. Upon endocytosis, we observed HEP-coated nanoparticles in intracellular vesicles and the cytoplasm, demonstrating the potential for nanoparticle escape from intracellular vesicles. Competition with other glycosaminoglycan types inhibited the endocytosis of HEP-coated nanoparticles only partially. We further found that nanoparticle uptake into innate immune cells can be controlled by more than 3 orders of magnitude via systematically varying the HEP surface density. Our results suggest a substantial potential for HEP-coated nanoparticles to target innate immune cells for efficient intracellular delivery, including into the cytoplasm. This HEP nanoparticle surface engineering technology may be broadly used to develop efficient nanoscale devices for drug and gene delivery as well as possibly for gene editing and immuno-engineering applications.

Inflammatory Disease Affecting the Central Nervous System in Dogs: A Retrospective Study in England (2010-2019).

The epidemiology of inflammatory diseases affecting the central nervous system (CNS) in dogs is largely unknown. We aimed to report the relative proportion of different causes of inflammatory disease affecting the CNS in dogs and identify predictors for infectious vs. immune-mediated conditions and predictors for the most common diseases affecting the brain and the spinal cord. This was a retrospective cohort study over a 10-year period in 2 referral institutions using multivariable and multinomial logistic regression for identification of risk factors. In total, 1,140 client-owned dogs diagnosed with inflammatory disease affecting the CNS were included. Fifteen different diagnoses were identified, with immune-mediated (83.6%) disease being more common than infectious conditions (16.4%). The most common immune-mediated conditions diagnosed were meningoencephalitis of unknown origin (47.5%) and steroid-responsive meningitis-arteritis (30.7%), and the most common infectious conditions were discospondylitis (9.3%) and otogenic intracranial infection (2.2%). Older age (p < 0.001, OR = 1.019, 95% CI: 1.014-1.024), higher body weight (p < 0.001, OR = 1.049, 95% CI: 1.025-1.074), male sex (p = 0.009, OR = 1.685, 95% CI: 1.141-2.488), longer duration of the clinical signs before presentation (p < 0.001, OR = 1.011, 95% CI: 1.006-1.017), progressive nature of the clinical signs (p < 0.001, OR = 2.295, 95% CI: 1.463-3.599), identification of a possibly associated preceding event (p = 0.0012, OR = 1.93, 95% CI: 1.159-3.213), and hyperesthesia on presentation (p < 0.001, OR = 2.303, 95% CI: 1.528-3.473) were associated with a diagnosis of infectious diseases. Our data shows that immune-mediated diseases are more common than infectious conditions as a cause for inflammatory CNS disease in dogs. The risk factors for the most common diagnoses were identified from signalment, history, and findings of the physical and neurological examinations to give valuable information that can guide clinicians with their investigations.

Limited dorsal myeloschisis in three cats: a distinctive form of neural tube defect.

CASE SERIES SUMMARY: The aim of this case series was to describe the clinical presentation, imaging findings and histopathology of three cats with limited dorsal myeloschisis (LDM). The history, examination and MRI sequences were reviewed in three cases presented to a single referral hospital. The surgery report and histopathology were described in two cases. All cats were young (10 weeks old, 5 months old, 4 years old), presenting with varying degrees of progressive paraparesis. All had a midline skin defect overlying the spinal column that was either sunken or saccular, containing fluid thought to be cerebrospinal fluid. MRI sequences demonstrated tissue extending from the dura through an overlying bifid spinous process and attached to the dermis, with associated spinal cord tethering, atrophy and syringomyelia. Lesions were located at L2-L3, T8-T9 and L4. Histopathology described a fibroneural stalk with a glio-ependymal lining, surrounded by glial nests and nerve fibres. The youngest and most severely affected was euthanased, while the other two underwent surgery. Both regained independent ambulation with persistent paraparesis; however, one required ongoing management of urinary incontinence. RELEVANCE AND NOVEL INFORMATION: LDM is a primary neural tube defect that may result in neurological deficits, including bladder dysfunction, and is characterised by a fibroneural stalk between the dermis and the spinal cord. Distinct MRI features, such as a visible intrathecal tract, dorsally tethered cord and syringomyelia, help distinguish this condition from the clinically similar dermoid sinus. The presence of progressive neurological signs, with a palpable midline defect overlying the affected spinal cord segment, may raise suspicion for this clinical entity in veterinary patients.