Early mechanisms of neutrophil activation and transmigration in acute lung injury

Introduction:Neutrophil transmigration is multifactorial and primarily driven by selectins and β₂-integrins (CD11b/CD18), whose expression are dependent on the underlying stimulus. Ventilator-induced lung injury (VILI) results in a predominantly CD18-independent mechanism of neutrophil recruitment, while direct endotoxin-induced lung injury results from a CD18-dependent mechanism. We previously observed that lack of NADPH oxidases DUOX1 and DUOX2 resulted in reduced neutrophil influx in a VILI model of lung injury but had no influence on neutrophil influx after LPS exposure. Based on these observations, we hypothesized that DUOX1/DUOX2 are an important component of CD18-independent mechanisms of neutrophil recruitment in the lung. Methods:We exposed Duoxa ^-/- (KO) mice and Duoxa ^+/+ (WT) mice to either an intratracheal exposure of lipopolysaccharide (LPS/endotoxin)-or high tidal volume ventilation and compared expression of neutrophil markers between groups. WT mice (129S6/SvEvTac) were obtained from Taconic Biosciences (One Discovery Drive Suite 304; Rensselaer, NY 1244) and were allowed to acclimatize for one week prior to study enrollment. KO mice were generated as previously described [Grasberger 2012] and bred in-house on a 129S6 background. We provided positive-pressure ventilation at a tidal volume of 10 ml/kg with 2 cmH20 positive end-expiratory pressure (PEEP). Mice were assigned to groups consisting of KO (n = 5) and WT (n = 5) in each group and divided into non-ventilated, positive-pressure ventilation, or LPS IT exposure groups. Positive-pressure ventilation was instituted for 4-h using a FlexiVent (Flexiware 8.1, Scireq, Montreal, QC, Canada). Lipopolysaccharide (Salmonella enterica serotype tryphimurium L6143, Millipore Sigma) was administered via an intratracheal (IT) route at a dose of 0.1 mg/kg. Mice were humanely euthanized at 4-h post-injection consistent with the UC Davis IAUCAC-approved protocol. Results:As previously observed, neutrophilic influx into the airways was significantly impaired in the Duoxa ^-/- (KO) mice after VILI, but not after LPS exposure. LPS-induced lung injury resulted in upregulation of CD11b⁺ neutrophils and shedding of CD62L and CD162 regardless of DUOX expression, whereas VILI resulted in upregulation of CD49⁺ neutrophils in the Duoxa ^+/+ (WT) mice but not the Duoxa ^-/- (KO) mice. Conclusion:Our data suggest DUOX is required for CD18-independent mechanisms of neutrophil recruitment in the lung induced by acute lung injury, but not for canonical CD18depedent mechanisms after LPS exposure.

Diagnostic yield of cytologic analysis of pericardial effusion in dogs

Background

Pericardial effusion cytology is believed by many to be of limited value, yet few studies have evaluated its diagnostic utility.

Objectives

To determine the diagnostic utility of cytologic analysis of pericardial effusion in dogs and to determine if consideration of additional data could improve the diagnostic yield.

Animals

Two hundred and fifty‐nine dogs with cytologic analysis of pericardial effusion performed between April 1990 and June 2012.

Methods

Electronic medical records from a university teaching hospital were retrospectively reviewed; signalment, complete blood count, serum biochemistry, cytologic analysis of pericardial effusion, and echocardiographic data were recorded. Cytology was classified as diagnostic (infectious or neoplastic) or nondiagnostic (hemorrhagic or other) and groups were compared with multiple Student's t‐tests.

Results

Cytology was grouped as nondiagnostic (92.3%) or diagnostic (7.7%) and characterized as hemorrhagic (90%), neoplastic (4.6%), infectious (3.1%), or other (2.3%). Overall cytologic analysis of pericardial effusion diagnostic utility was 7.7% and increased to 20.3% if the effusion hematocrit (HCT) <10%; echocardiographic evidence of a mass did not result in a significant increase in the diagnostic utility.

Conclusions and Clinical Importance

The diagnostic utility of cytologic analysis of canine pericardial effusion is variable depending on the underlying etiology. In this group of dogs, the diagnostic yield of cytologic analysis was greater for pericardial effusion samples in which the HCT was less than 10%.

Technical details of intraoperative lymphatic mapping for early stage melanoma

The initial route of metastases in most patients with melanoma is via the lymphatics to the regional nodes. However, routine lymphadenectomy for patients with clinical stage I melanoma remains controversial because most of these patients do not have nodal metastases, are unlikely to benefit from the operation, and may suffer troublesome postoperative edema of the limbs. A new procedure was developed using vital dyes that permits intraoperative identification of the sentinel lymph node, the lymph node nearest the site of the primary melanoma, on the direct drainage pathway. The most likely site of early metastases, the sentinel node can be removed for immediate intraoperative study to identify clinically occult melanoma cells. We successfully identified the sentinel node(s) in 194 of 237 lymphatic basins and detected metastases in 40 specimens (21%) on examination of routine hematoxylin-eosin-stained slides (12%) or exclusively in immunohistochemically stained preparations (9%). Metastases were present in 47 (18%) of 259 sentinel nodes, while nonsentinel nodes were the sole site of metastasis in only two of 3079 nodes from 194 lymphadenectomy specimens that had an identifiable sentinel node, a false-negative rate of less than 1%. Thus, this technique identifies, with a high degree of accuracy, patients with early stage melanoma who have nodal metastases and are likely to benefit from radical lymphadenectomy.

Lymphatic drainage of skin to a sentinel lymph node in a feline model

To determine the feasibility of selective lymphadenectomy, the authors developed a feline model to identify and determine the utility of mapping dyes for this purpose. Adult cats were injected intradermally with a variety of mapping substances to determine whether the anatomic site of injection had a predictable pattern of drainage to a particular lymph node. Isosulfan blue provided the optimal mapping material. Injection of isosulfan blue intradermally into the skin of the medial thigh consistently led to coloration of the central lymph node, whereas intradermal abdominal wall injections and intradermal lateral thigh injections resulted in coloration of the lateral lymph node. Intradermal injections into skin about the perineum resulted in coloration of the most medial lymph node only. The feline model proved to a useful model to examine the utility of mapping dyes and to demonstrate dermal lymphatics. The predictable pattern of drainage of the skin in this feline model supports the feasibility of selective lymphadenectomy.

Natural history and selective management of in transit melanoma

Ninety five patients who developed in transit melanoma either as their initial site of recurrent melanoma or following regional node metastases were retrospectively reviewed. In transit melanoma occurred most frequently on the lower extremity and appeared to be associated with deeply invasive primary tumors. The median time to development of in transit melanoma was 16 months. Eighty-two (86%) of these patients have progressed to systemic disease from 2 to 244 months (median 16 months) following the development of in transit melanoma, and 72 (79%) died (median survival 19 months). Survival appears to correlate with the extent of in transit melanoma and with the disease-free interval. These findings suggest that in transit melanoma represents an early manifestation of systemic disease, warranting careful clinical follow-up and perhaps systemic treatment, when effective therapy becomes available. However, some patients will respond to local immunotherapy, surgical excision, and isolated limb perfusion and will enjoy significant length and quality of life. This sequential approach remains the treatment of choice for this manifestation of metastatic melanoma.

Surgical treatment of lymph nodes with metastatic melanoma from unknown primary site

To determine the prognosis of patients with lymph node metastases from an unknown primary melanoma, we retrospectively reviewed the clinicopathologic features of 188 such patients treated from 1971 through 1986 and compared their records with those of patients with clinical stage II melanoma with known primary lesions. Patients with lymph node metastases from an unknown primary melanoma represented 4.6% of all patients with melanoma treated during that period. The five- and ten-year survival rates were 42% and 40%, respectively (median, 37 months). When stratified by number of tumor-containing lymph nodes, there was no significant difference in survival between patients with an unknown primary melanoma and lymph node metastases and those with clinical stage II melanoma and known primary sites. The prognosis of the former patients is no worse than that of patients with lymph node metastases from a known primary site and should be treated in a comparable manner.

Natural history of surgically treated mucosal melanoma

Thirty-three patients with melanoma arising in a mucosal site were reviewed. Sixteen patients were treated either with abdominoperineal resection or radical vulvectomy and superficial inguinal lymphadenectomy. Three patients were treated palliatively. Fourteen patients were treated conservatively with local excision, wide local excision, and radiation therapy. One patient received systemic chemotherapy and radiation therapy. Local recurrence developed in seven patients. The overall survival rate was poor. Neither local control nor survival appeared to be influenced by the initial surgical approach.

Histologic features relating to prognosis in synovial sarcoma

Although the American Joint Commission has classified all synovial sarcomas as "high grade," histologic subtypes can be identified. By histologically subclassifying synovial sarcoma tumors according to percent glandularity and mitotic rates, the authors were able to define high-risk and low-risk patients. Charts and original pathologic slides were reviewed on 45 synovial sarcoma patients. With a 41-month median follow-up, the low-risk patients showed 100% survival, whereas the high-risk patients showed 37% survival.