Kamani Lankachandra

Fat Embolism: Evolution of Histopathological Changes in the Rat Lung

The pathophysiology of Fat Embolism Syndrome (FES) is poorly understood and subject to some controversy. Evaluation of the evolution of histological changes in the lungs of patients with FES is impractical. The current theories of FES were established through acute clinical observations and acute animal experiments, but sequential changes in the histology of lungs over a prolonged period have not been made. The progressive effects of fat embolization of the lungs were examined in a rat model over a period of 11 days. Triolein, a major bone marrow fat, was administered to conscious Sprague‐Dawley rats via the caudal vein. Rats were euthanized at 24, 48, 96 h, and 11 days, but some died within a few hours. Histomorphometric evaluations of lung tissue were made, including stains for fat, collagen, and smooth muscle actin. Arterial and arteriolar patency decreased progressively up to 96 h, but returned toward normal after 11 days. A striking finding was the very early presence of inflammation and fibrosis after only several hours, persisting up to 11 days. The results of this study provide evidence of both very early and prolonged changes due to fat embolization.

Mitigating effects of captopril and losartan on lung histopathology in a rat model of fat embolism.

BACKGROUND Fat embolization (FE) is an often overlooked and poorly understood complication of skeletal trauma and some orthopedic procedures. Fat embolism can lead to major pulmonary damage associated with fat embolism syndrome (FES). METHODS A model of FE in unanesthetized rats, using intravenous injection of the neutral fat triolein, was used to study the potential therapeutic effect on lung histopathology of altering the production of, or response to, endogenous angiotensin (Ang) II. Either captopril, an Ang I converting enzyme inhibitor, or losartan, an Ang II type 1 receptor blocker, was injected 1 hour after FE by triolein injection. After euthanasia at 48 hours, histopathologic evaluation was used to compare the drug-treated animals with control animals that received only triolein. RESULTS Histology of the lungs of rats treated only with triolein revealed severe, diffuse pathology. Alveolar septa showed severe, diffuse inflammation. Bronchial lumina showed severe mucosal epithelial loss. The media of the pulmonary small arteries and arterioles was thicker, and the lumen patency was reduced 60% to 70%. Trichrome staining confirmed the abundant presence of collagen in the media and adventitia, as well as collagen infiltrating the bronchial musculature. Both captopril and losartan treatments reduced the inflammatory, vasoconstrictor, and profibrotic effects present at 48 hours (p<0.001). With treatment, the vascular lumen remained patent, and the fat droplets were reduced in size and number. There was a reduction in the number of infiltrating leukocytes, macrophages, myofibroblasts, and eosinophils, along with a significant decrease in hemorrhage and collagen deposition (p<0.001). Pathologic changes in bronchial epithelium were also diminished. CONCLUSIONS The results suggest that the use of drugs that act on the renin-Ang system might provide an effective and targeted therapy for fat embolism syndrome.

3q26 Amplification Is an Effective Negative Triage Test for LSIL: A Historical Prospective Study

Background Women with low grade squamous intraepithelial lesions (LSIL) at cervical cancer screening are currently referred for further diagnostic work up despite 80% having no precancerous lesion. The primary purpose of this study is to measure the test characteristics of 3q26 chromosome gain (3q26 gain) as a host marker of carcinogenesis in women with LSIL. A negative triage test may allow these women to be followed by cytology alone without immediate referral to colposcopy. Methods and Findings A historical prospective study was designed to measure 3q26 gain from the archived liquid cytology specimens diagnosed as LSIL among women attending colposcopy between 2007 and 2009. 3q26 gain was assessed on the index liquid sample; and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were measured at immediate triage and at 6–16 months after colposcopic biopsy. The sensitivity of 3q26 gain measured at immediate triage from automated and manually reviewed tests in 65 non-pregnant unique women was 70% (95% CI: 35, 93) with a NPV of 89% (95% CI: 78, 96). The sensitivity and NPV increased to 80% (95% CI: 28, 99) and 98% (95% CI: 87, 100), respectively, when only the automated method of detecting 3q26 gain was used. Conclusions 3q26 gain demonstrates high sensitivity and NPV as a negative triage test for women with LSIL, allowing possible guideline changes to routine surveillance instead of immediate colposcopy. Prospective studies are ongoing to establish the sensitivity, specificity, PPV and NPV of 3q26 gain for LSIL over time.

Human Papillomavirus-58 and -73―Associated Digital Squamous Cell Carcinoma in a Patient With Aggressive Digital Papillary Adenocarcinoma

Aggressive digital papillary adenocarcinoma (ADPA) is a rare tumor that is considered to arise from eccrine sweat glands of the skin. It occurs predominantly in men with a mean age in the sixth decade. It shows a strong tendency for local recurrence and has the potential to metastasize to distant sites. Prompt diagnosis and regular follow-up are important to ensure the best possible outcome. We discuss a case of recurrent ADPA associated with subsequent squamous cell carcinoma (SCC) in different contralateral digits in a 55-year-old man. One SCC lesion tested positive for human papillomavirus (HPV)-58. HPV-associated digital SCCs have been reported; most cases are HPV-16 positive. This report describes a rare case of an HPV-58-positive invasive digital SCC and an HPV-73-positive SCC in situ associated with ADPA.

Infiltrating myoepithelial carcinoma of the breast, a case report and cytologic-histologic correlation

IntroductionInfiltrating myoepithelial carcinoma remains a rarely encountered lesion of the breast. The few cases that have surfaced firmly document the histopathology of this tumor, but its cytologic characteristics seemingly have been described in only one other report.Case presentationHere we present the cytologic findings from a case of infiltrating myoepithelial carcinoma of the breast in a 52-year-old female and provide a histologic correlation with the subsequent biopsy and mastectomy specimens. While the cytology specimens displayed more myoepithelial cellular heterogeneity than was present on histology, a number of cytologic features including hypercellularity, pleomorphic spindle cells, and mitotic activity correlated well with the histopathology.ConclusionThe role of fine needle aspiration in the diagnosis of mammary myoepithelial carcinoma, in this case, was to establish malignancy rather than to arrive at a specific diagnosis, as a number of different entities potentially can mimic this neoplasm on cytologic specimens.

Deep penetrating nevus: a case report and brief literature review

Background -Deep penetrating nevus (DPN) is a distinct variant of melanocytic nevus and remains a histopathologic challenge to pathologists because of its resemblance to blue nevus, malignant melanoma, pigmented Spitz nevus, and congenital melanocytic nevus. It often goes unrecognized due to its relative rarity.Case presentation -Here we report a case of DPN of the left anterior leg in a 51-year old female. A brief review of the literature shows that these lesions have a distinct growth pattern and cellular morphology that can differentiate these lesions from other entities including malignant melanoma.Conclusion -It is important to recognize these features because DPN carries a better prognosis than malignant melanoma.

Down-regulation of placental neuropilin-1 in fetal growth restriction.

BACKGROUND Fetal growth restriction (FGR) is associated with adverse outcomes extending from fetal to adult life, and thus, constitutes a major health care challenge. Fetuses with progressive growth restriction show increasing impedance in the umbilical artery flow, which may become absent during end-diastole. Absent end-diastolic flow (AEDF) is associated with adverse perinatal outcomes including stillbirths and perinatal asphyxia. Placentas from such pregnancies demonstrate deficient fetoplacental vascular branching. Current evidence, moreover, indicates an antiangiogenic state in maternal circulation in several pregnancy complications including preeclampsia, small-for-gestational-age births, fetal death, and preterm labor. The angiogenic mediators in maternal circulation are predominantly of placental origin. Information, however, on the role of specific proangiogenic and antiangiogenic mechanisms operating at the placental level remains limited. Elucidation of these placenta-specific angiogenic mechanisms will not only extend our understanding of the causal pathway for restricted fetal growth but may also lead to the development of biomarkers that may allow early recognition of FGR. OBJECTIVE We sought to test the hypothesis that fetoplacental angiogenic gene expression is altered in pregnancies complicated with FGR and umbilical artery Doppler AEDF. STUDY DESIGN Placental samples were collected from FGR pregnancies complicated with umbilical artery Doppler AEDF (study group, n = 7), and from uncomplicated pregnancies (control group, n = 7), all delivered by cesarean during the last trimester of pregnancy. Angiogenic oligonucleotide microarray analysis was performed and was corroborated by quantitative real-time polymerase chain reaction, Western blot analysis, and immunohistochemistry. The Student t test with Bonferroni correction was used with P < .05 considered statistically significant. Independent groups t test was used to analyze the immunostain intensity scores with a P < .05 considered statistically significant. RESULTS Our microarray results showed that among several differentially expressed angiogenic genes in the growth-restricted group, only the down-regulation of neuropilin (NRP)-1 was most significant (P < .0007). Quantitative real-time polymerase chain reaction confirmed a significantly lower NRP-1 gene expression in the FGR group than in the control group (mean ± SD (ˆ)cycle threshold: 0.624 ± 0.55 and 1.325 ± 0.84, respectively, P = .04). Western blot validated significantly lower NRP-1 protein expression in the FGR group than in the control group (mean ± SD NRP-1/β-actin ratio: 0.13 ± 0.04 and 0.34 ± 0.05, respectively, P < .001). Finally, immunohistochemistry of placental villi further corroborated a significantly decreased expression of NRP-1 in the FGR group (P = .006). CONCLUSION The study demonstrated significant down-regulation of placental NRP-1 expression in FGR pregnancies complicated with AEDF in umbilical artery. As NRP-1 is known to promote sprouting angiogenesis, its down-regulation may be involved in the deficient vascular branching observed in FGR placentas suggesting the presence of an antiangiogenic state. Further studies may elucidate such a causal role and may lead to the development of novel diagnostic and therapeutic tools.

Persistent and progressive pulmonary fibrotic changes in a model of fat embolism.

BACKGROUND: Fat embolism (FE) after trauma and some orthopedic procedures is known to cause acute lung injury, including acute respiratory distress syndrome. However, its potential long-term effects on the lung are unknown. A previous study using a rat model of FE found significant histopathologic changes in the lungs after intravenous injection of triolein for up to 11 days. This study detailed the persistence of the lung damage and investigated the input of the renin-angiotensin system in its pathology. METHODS: Unanesthetized rats were injected via the tail vein with 0.2 mL saline or triolein. After euthanasia, at 3 weeks or 6 weeks, lung sections were stained to highlight cellular structure, presence of collagen and fat, or immunolabeled for smooth muscle actin or angiotensin peptides. RESULTS: At 3 weeks or 6 weeks after triolein injection, there was no dilatation of the heart or inferior vena cava, no congestion of the liver or spleen, no adventitial edema, nor was fluid present in alveoli or pleural cavity as reported in animals at earlier time points. Persisting pathology included reduced lumen patency, thickening of the media of small arteries and arterioles, and vascular and septal inflammation. Although the fat content of the lung decreased from week 3 to week 6, there was a progressive increase in collagen, smooth muscle actin, and angiotensin peptides. CONCLUSIONS: This model extends the effect of FE on pulmonary pathology to 6 weeks, revealing persistent vasculitis, septal inflammation, and progressive fibrotic changes which are associated with increased presence of angiotensin peptides.

Sanguinarine inhibits pancreatic cancer stem cell characteristics by inducing oxidative stress and suppressing sonic hedgehog-Gli-Nanog pathway

Sonic hedgehog pathway is highly activated in pancreatic cancer stem cells (CSC) which play crucial roles in cancer initiation, progression and metastasis. However, the molecular mechanisms by which sanguinarine regulates pancreatic CSC characteristics is not well understood. The objectives of this study were to examine the molecular mechanisms by which sanguinarine regulates pancreatic CSC characteristics. Sanguinarine inhibited cell proliferation and colony formation and induced apoptosis through oxidative damage. Sanguinarine inhibited self-renewal capacity of pancreatic CSCs isolated from human and KrasG12D mice. Furthermore, sanguinarine suppressed epithelial-mesenchymal transition (EMT) by up-regulating E-cadherin and inhibiting N-cadherin. Significant decrease in expression level of Snail, Slug and Zeb1 corroborated the suppression of EMT in sanguinarine treated pancreatic CSCS. The ability of sanguinarine to inhibit pluripotency maintaining factors and CSC markers suggest that sanguinarine can be an effective agent for inhibiting pancreatic cancer growth and development by targeting CSCs. Furthermore, sanguinarine inhibited Shh-Gli pathway leading to modulation of Gli target genes in pancreatic CSCs. Chromatin immunoprecipitation assay demonstrated that Nanog directly binds to promoters of Cdk2, Cdk6, FGF4, c-Myc and Oct4, and sanguinarine inhibits the binding of Nanog with these genes, suggesting the direct involvement of Nanog in cell cycle, pluripotency and self-renewal. To further investigate the role of Shh-Gli-Nanog pathway, we regulated Shh signaling either by Shh protein or Nanog overexpression. Enforced activation of Shh or overexpression of Nanog counteracted the inhibitory effects of sanguinarine on pancreatic CSC proliferation, suggesting the actions of sanguinarine are mediated, at least in part, through Shh-Gli-Nanog pathway. Our studies suggest that sanguinarine can be used for the treatment and/or prevention of pancreatic cancer by targeting CSCs.

Fetoplacental regional variations in the expression of angiopoietin-1, angiopoietin-2, and Tie2 in normal-term and near-term pregnancies.

Abstract Background: Angiopoietin-1 (Ang1), angiopoietin-2 (Ang2), and the receptor tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (Tie2) are known to be involved in fetoplacental angiogenesis adequacy, which is a primary determinant of fetal growth. Regional variations in Ang1, Ang2, and Tie2 remain unknown, although fetoplacental vascularity and gene expressions differ between the placental center and the periphery. Objective: The aim of this study was to test the hypothesis that there are regional variations in the expression of these angiopoietins in human placentas from uncomplicated term and near term pregnancies. Study design: In this prospective study, central and peripheral samples were collected from fresh placentas from normal-term and near-term pregnancies delivered by Cesarean section (n = 7, 36–41 week gestation) prior to the onset of labor. Regional differences in Ang1, Ang2, and Tie2 protein expressions were measured by Western blot and densitometric analyses with b-actin normalization, and their fetoplacental regional localization assessed by immunohistochemistry. The Ang1 and Ang2 ratios at central and peripheral sites were determined. Statistical analysis was performed using Student’s t-test. Results: Ang1 protein expression was higher in the placental periphery than in the center (2.48 ± 0.42 versus 1.74 ± 0.27, p = 0.01). In contrast, Ang2 protein expression was greater in the placental center than in the periphery (10.10 ± 1.82 versus 7.15 ± 1.12, respectively, p = 0.03). The Ang1–Ang2 ratio reflected these differential expressions. Tie2 protein expression was higher in the placental periphery than in the center (0.21 ± 0.02 versus 0.16 ± 0.02, p = 0.003). The immunoreactivity of Ang1 and Tie2 was stronger in the periphery than in the center, and that of Ang2 was stronger in the center than in the periphery. Conclusions: Ang1, Ang2, and Tie2 are differentially expressed in placental center and periphery. Ang1/Ang2 ratio reflects this regional variation in the angiogenic balance that has implications for fetoplacental villous angiogenesis. The results also demonstrate the importance of considering the location of placental sampling sites for any future investigations of fetoplacental villous angiogenesis.