Acute Appendicitis in the Setting of Infectious Mononucleosis: A Case Report.

Infectious mononucleosis (IM) is a viral illness caused by the Epstein-Barr virus that typically manifests with pharyngitis, lymphadenopathy, and fatigue. In rare cases, IM can cause acute appendicitis. We present the case of an 18-year-old female who arrived at the emergency department with worsening abdominal pain and an ongoing cough. Initial imaging showed a questionably dilated appendix, and a follow-up examination revealed cervical lymphadenopathy. She later returned to the ED with severe abdominal pain, clinical signs of acute appendicitis, and a positive monospot test, which led to an appendectomy. This case illustrates the need for complete history taking and thorough physical examination in patients with acute appendicitis, as their condition may be due to an atypical underlying cause.

Evidence based management of sports related concussion.

Sports related concussion (SRC) is a common condition evaluated by healthcare professionals. In an article entitled "Return to Play After Concussion: Clinical Guidelines for Young Athletes" published in the December 2019 issue of the Journal of the American Osteopathic Association, guidelines for the management of SRC were presented to assist healthcare professionals in the management of patients with SRC. However, much of the information presented in that article is contradicted by current expert recommendations and evidence based practice guidelines. The management of SRC has evolved to a nuanced, domain driven diagnosis requiring a multidisciplinary treatment team and a customized management plan for each patient to ensure competent treatment of patients with SRC. As such, this Commentary summarizes current recommendations for diagnosis and management of SRC.

Anti-VEGF-A therapy reduces lymphatic vessel density and expression of VEGFR-3 in an orthotopic breast tumor model.

Because metastasis contributes significantly to cancer mortality, understanding its mechanisms is crucial to developing effective therapy. Metastasis is facilitated by lymphangiogenesis, the growth of new intratumoral or peritumoral lymphatic vessels from pre-existing vessels. Vascular endothelial growth factor A (VEGF-A) is a well-known angiogenic factor. Increasing evidence implicates VEGF-A in lymphangiogenesis, although the mechanism of its pro-lymphangiogenic effect is poorly understood. We examined the effect of the anti-VEGF-A neutralizing antibody 2C3 on tumor lymphangiogenesis and metastasis in an orthotopic breast carcinoma model using MDA-MB-231 cells and its luciferase-tagged derivative, 231-Luc(+) cells. Anti-VEGF-A antibody therapy reduced blood and lymphatic vessel densities by 70% and 80%, respectively, compared with the control antibody. Treatment with 2C3 antibody also decreased incidence of lymphatic and pulmonary metastases by 3.2- and 4.5-fold, respectively. Macrophage infiltration was reduced in 2C3-treated tumors by 32%, but VEGF-C expression was unchanged. In contrast, neoplastic cells and blood vessels in tumors from 2C3-treated mice expressed significantly less angiopoietin-2 (Ang-2) than tumors from control mice. The reduction in Ang-2 was associated with inhibition of VEGFR-3 expression in intratumoral lymphatic endothelial cells. Both VEGF-A and Ang-2 upregulated the expression of VEGFR-3 in cultured lymphatic endothelial cells. VEGF-A induced proliferation of lymphatic endothelial cells was reduced by 50% by soluble Tie-2, suggesting that Ang-2 is an intermediary of the pro-lymphangiogenic VEGF-A effect. These results suggest a novel mechanism by which anti-VEGF-A therapy may suppress tumor lymphangiogenesis and subsequent metastasis supporting the use of anti-VEGF-A therapy to control metastasis clinically.

Molecular profile and proliferative responses of rat lymphatic endothelial cells in culture.

BACKGROUND: Lymphangiogenesis plays an important role in metastasis of many solid tumors. To study lymphangiogenesis under controlled conditions, an in vitro model is needed. The goal of this work was to establish such an in vitro model by determining a molecular profile of rat mesenteric lymphatic endothelial cells (RMLEC) and characterizing their proliferative responses to angiogenic and lymphangiogenic factors, such as vascular endothelial growth factor A and C (VEGF-A and VEGF-C). METHODS AND RESULTS: RMLEC strongly expressed most lymphatic-specific markers, including Prox-1, LYVE-1, and VEGFR-3. Proliferation of RMLEC was serum and heparin dependent. In the presence of low (2%) serum concentration, exogenously added VEGF-A and VEGFC stimulated RMLEC in a linear and dose-dependent manner. This effect was abrogated by anti-VEGF-A and VEGF-C antibodies, as well as by soluble Tie-2 and Flt-4 fusion proteins. Abrogation was reversed by VEGF-A, suggesting that this factor as an important regulator of lymphangiogenesis. CONCLUSIONS: Cultured RMLEC preserved a molecular profile consistent with the phenotype of lymphatic endothelium in vivo and respond to either VEGF-A or VEGF-C factors. VEGFA was able to rescue RMLEC proliferation inhibited by a neutralizing VEGF-C antibody or soluble Tie-2 fusion protein. These results support the existence of cross-talk among angiogenic and lymphangiogenic factors. This work established experimental conditions that allow in vitro modeling of lymphatic endothelial responses to lymphangiogenic regulators. Preliminary results using this model suggest that VEGF-A, VEGF-C, and angiopoietins work in concert to promote lymphangiogenesis in vivo.