Microvasculature of the suspensory ligament of the equine hind limb.

OBJECTIVE: To describe the microvascular anatomy of the equine hind limb suspensory ligament. ANIMALS: 18 hind limbs harvested from 9 adult horses euthanized for reasons unrelated to lameness. METHODS: A catheter was placed in the transected cranial tibial artery at the level of the mid-distal tibia for each hind limb and used to inject 120 to 150 mL of contrast medium (2 limbs) to identify principal vasculature using contrast-enhanced CT or India ink (11 limbs) to identify microvasculature using the Spalteholz tissue-clearing technique. Routine histologic evaluation was performed on transverse sections from 4 hind limbs. RESULTS: The hind limb suspensory ligament is principally supplied by branches of the medial and lateral plantar metatarsal arteries and, to a lesser extent, the medial and lateral plantar arteries as well as the associated proximal and distal deep plantar arches. A uniformly distributed intraligamentous microvascular supply was observed without relative deficiencies in vascularity between the proximal, midbody, and distal regions. Histologic examination supported these findings, demonstrating a network of connective tissue surrounding and entering the suspensory ligament containing cross-sections of branches of the principal vasculature. CLINICAL RELEVANCE: The equine hind limb suspensory ligament has a uniformly distributed and abundant microvascular supply throughout its length, with no evidence of relative deficiency of vascular supply in any region. A region of hypovascularity does not appear to be a viable explanation for the high rate of injury to and commonality of lameness associated with the proximal hind suspensory ligament in horses.

A Novel Vaccine Strategy to Prevent Cytauxzoonosis in Domestic Cats.

Cytauxzoonosis is caused by Cytauxzoon felis (C. felis), a tick-borne parasite that causes severe disease in domestic cats in the United States. Currently, there is no vaccine to prevent this fatal disease, as traditional vaccine development strategies have been limited by the inability to culture this parasite in vitro. Here, we used a replication-defective human adenoviral vector (AdHu5) to deliver C. felis-specific immunogenic antigens and induce a cell-mediated and humoral immune response in cats. Cats (n = 6 per group) received either the vaccine or placebo in two doses, 4 weeks apart, followed by experimental challenge with C. felis at 5 weeks post-second dose. While the vaccine induced significant cell-mediated and humoral immune responses in immunized cats, it did not ultimately prevent infection with C. felis. However, immunization significantly delayed the onset of clinical signs and reduced febrility during C. felis infection. This AdHu5 vaccine platform shows promising results as a vaccination strategy against cytauxzoonosis.

Clinicians' Perspectives on Racism and Black Women's Maternal Health.

Objective: The objective of this study was to explore clinician perceptions of how racism affects Black women's pregnancy experiences, perinatal care, and birth outcomes. Materials and Methods: We conducted 25 semi-structured interviews with perinatal care clinicians practicing in the San Francisco Bay Area (January to March 2019) who serve racially diverse women. Participants were primarily recruited through "Dear Perinatal Care Provider" email correspondences sent through department listservs. Culturally concordant, qualitatively trained research assistants conducted all interviews in person. The interviews ranged from 30 to 60 minutes and were audio-recorded and professionally transcribed verbatim. We used the constant comparative method consistent with grounded theory to analyze data. Results: Most participants were obstetrician/gynecologists (n = 11, 44%) or certified nurse midwives (n = 8, 32%), had worked in their current role for 1 to 5 years (n = 10, 40%), and identified as white (n = 16, 64%). Three themes emerged from the interviews: provision of inequitable care (e.g., I had a woman who had a massive complication during her labor course and felt like she wasn't being treated seriously); surveillance of Black women and families (e.g., A urine tox screen on the Black baby even though it was not indicated, and they didn't do it on the white baby when, in fact, it was indicated); and structural care issues (e.g., the history of medical racial experimentation). Conclusion: Clinicians' views about how racism is currently operating and negatively impacting Black women's care experiences, health outcomes, and well-being in medical institutions will be used to develop a racial equity training for perinatal care clinicians in collaboration with Black women and clinicians.

Psychometric validation of a patient-reported experience measure of obstetric racism© (The PREM-OB Scale™ suite).

BACKGROUND: Perinatal quality improvement lacks valid tools to measure adverse hospital experiences disproportionately impacting Black mothers and birthing people. Measuring and mitigating harm requires using a framework that centers the lived experiences of Black birthing people in evaluating inequitable care, namely, obstetric racism. We sought to develop a valid patient-reported experience measure (PREM) of Obstetric Racism© in hospital-based intrapartum care designed for, by, and with Black women as patient, community, and content experts. METHODS: PROMIS© instrument development standards adapted with cultural rigor methodology. Phase 1 included item pool generation, modified Delphi method, and cognitive interviews. Phase 2 evaluated the item pool using factor analysis and item response theory. RESULTS: Items were identified or written to cover 7 previously identified theoretical domains. 806 Black mothers and birthing people completed the pilot test. Factor analysis concluded a 3 factor structure with good fit indices (CFI = 0.931-0.977, RMSEA = 0.087-0.10, R2  > .3, residual correlation < 0.15). All items in each factor fit the IRT model and were able to be calibrated. Factor 1, "Humanity," had 31 items measuring experiences of safety and accountability, autonomy, communication, and empathy. A 12-item short form was created to ease respondent burden. Factor 2, "Racism," had 12 items measuring experiences of neglect and mistreatment. Factor 3, "Kinship," had 7 items measuring hospital denial and disruption of relationships between Black mothers and their child or support system. CONCLUSIONS: The PREM-OB Scale™ suite is a valid tool to characterize and quantify obstetric racism for use in perinatal improvement initiatives.

The First Immunocompetent Mouse Model of Strictly Human Pathogen, Borrelia recurrentis.

The spirochetal bacterium Borrelia recurrentis causes louse-borne relapsing fever (LBRF). B. recurrentis is unique because, as opposed to other Borrelia spirochetes, this strictly human pathogen is transmitted by lice. Despite the high mortality and historically proven epidemic potential and current outbreaks in African countries and Western Europe, research on LBRF has been obstructed by the lack of suitable animal models. The previously used grivet monkey model is associated with ethical concerns, among other issues. An existing immunodeficient mouse model does not limit bacteremia due to its impaired immune system. In this study, we used genetically diverse Collaborative Cross (CC) lines to develop the first LBRF immunocompetent mouse model. Out of 12 CC lines tested, CC046 mice consistently developed B. recurrentis-induced spirochetemia during the first 3 days postchallenge as concordantly detected by dark-field microscopy, culture, and quantitative PCR. However, spirochetemia was not detected from day 4 through day 10 postchallenge. The high-level spirochetemia (>107 cells/ml of blood) observed in CC046 mice was similar to that recorded in LBRF patients as well as immunocompetent mouse strains experimentally infected by tick-borne relapsing fever (RF) spirochetes, Borrelia hermsii and Borrelia persica. In contrast to the Old World and New World RF spirochetes, which develop multiple relapses (n = 3 to 9), B. recurrentis produced only single culture-detectable spirochetemia in CC046 mice. The lack of relapses may not be surprising, as LBRF patients and the grivet monkey model usually develop no or only 1 to 2 spirochetemic relapses. The novel model will now allow scientists to study B. recurrentis in the context of intact immunity.

Black Women's Perspectives on Structural Racism across the Reproductive Lifespan: A Conceptual Framework for Measurement Development.

BACKGROUND: Exposures to structural racism has been identified as one of the leading risk factors for adverse maternal and infant health outcomes among Black women; yet current measures of structural racism do not fully account for inequities seen in adverse maternal and infant health outcomes between Black and white women and infants. In response, the purpose of this study was to conceptualize structural racism from the perspectives of Black women across the reproductive lifespan and its potential impact on adverse maternal and infant health outcomes. METHODS: We conducted a series of focus groups with 32 Black women across the reproductive lifespan (5 preconception, 13 pregnant, and 14 postpartum). Study criteria including self-identifying as Black, residing in Oakland or Fresno, California and representing one of three reproductive life tracks (preconception, pregnant, postpartum). We consulted with study participants and an expert advisory board to validate emergent domains of structural racism. RESULTS: Nine domains of structural racism emerged from a ground theory constant comparative analysis: Negative Societal Views; Housing; Medical Care; Law Enforcement; Hidden Resources; Employment; Education, Community Infrastructure; and Policing Black Families. CONCLUSIONS FOR PRACTICE: Findings from this study suggest that there is an interplay among structural racism, and social and structural determinants of health which has negative impacts on Black women's sexual and reproductive health. Furthermore, findings from this study can be used to develop more comprehensive medical assessments and policies to address structural racism experienced by Black women across the reproductive lifespan.

Pathologic and flow cytometric features of a case of canine ventral cervical lymphangiosarcoma.

An 11-y-old spayed female German Shepherd was presented for a second opinion of ventral cervical swelling of 3-mo duration. On examination, the dog had significant dependent ventral cervical swelling. Enlarged lymph nodes with cystic changes and severe edematous facial swelling were noted on computed tomography. Fine-needle aspiration of the ventral cervical swelling revealed yellow-tinged fluid, with a predominance of lymphoid cells noted on cytologic examination. On cervical exploratory surgery, the left mandibular lymph node was surrounded by a large fluid pocket; biopsies of the lymph node were obtained. Impression smear cytology, flow cytometry, PCR for antigen receptor gene rearrangements, and histopathology were performed on samples from the left mandibular lymph node. Impression smear cytology revealed a population of atypical discrete cells. Flow cytometry identified a population of CD34+/CD45- large cells. A tumor of endothelial origin within the medulla of the lymph node was identified by histopathology, and lymphangiosarcoma was confirmed based on prospero-related homeobox gene 1 (PROX1) immunoreactivity. Our study describes the challenges in the diagnosis of a rarely reported entity and highlights that neoplastic endothelial cells should be considered as a differential when high proportions of CD34+/CD45- cells are present in flow cytometry.

Immersion Foot Syndrome in 6 Equids Exposed to Hurricane Floodwaters.

Prolonged exposure to water, known as immersion foot syndrome in humans, is a phenomenon first described in soldiers during World War I and characterized by dermal ischemic necrosis. In this report, we describe the pathologic findings of a condition resembling immersion foot syndrome in 5 horses and 1 donkey with prolonged floodwater exposure during Hurricane Harvey. At necropsy, all animals had dermal defects ventral to a sharply demarcated "water line" along the lateral trunk. In 5 animals, histologic examination revealed moderate to severe perivascular dermatitis with vasculitis and coagulative necrosis consistent with ischemia. The severity of the lesions progressed from ventral trunk to distal limbs and became more pronounced in the chronic cases. The pathophysiology of immersion foot syndrome is multifactorial and results from changes in the dermal microvasculature leading to thrombosis and ischemia. Prompt recognition of this disease may lead to appropriate patient management and decreased morbidity.