Surfactant Apoprotein A Research Articles

A Rare Benign Pulmonary Neoplasm: A Case Report of Benign Pulmonary Papillary Adenoma

SESSION TITLE: Lung Pathology 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Pulmonary papillary adenoma is rare solitary neoplasm which is typically discovered incidentally. Fewer than 30 cases have been reported in the current literature. We report a case of a benign papillary tumor of the lung. CASE PRESENTATION: A 61 year-old female, asymptomatic former smoker presented to pulmonary clinic for evaluation of a 3.3 x 2 cm pleural based mass in the posterior right lung base which was found incidentally on an abdominal CT. The pulmonary mass was confirmed with a dedicated CT chest. Electromagnetic navigation bronchoscopy was performed. Histopathology of the transbronchial biopsy revealed papillary growth pattern of cuboidal to columnar cells with somewhat fibrotic papillary stromal fronds. Neither atypia, necrosis, nor mitotic changes were present. The histological features were suggestive of benign pulmonary papillary adenoma. DISCUSSION: Pulmonary papillary adenoma is an uncommon neoplasm. On chest radiography, the tumor generally appears as a well-circumscribed mass located peripherally and posteriorly, without lobar predilection. This benign neoplasm occurs more commonly in patients age 7 - 60 years, predominantly in males. It is composed of type II pneumocytes, or Clara cell-lined papilla, that histochemical stain positive for thyroid transcription factor 1 (TTF-1), cytokeratin (CK), epithelial membrane antigen (EMA), surfactant apoprotein A (SPA) and Napsin A. It is primarily reported to be benign. However, a few studies have reported features of a slow growth rate and invasion into surrounding vessels, pleura, and adjacent parenchyma; therefore, this neoplasm may have intermediate malignant potential. Histologically, it shares features of a benign tumor (eg. Sclerosing pneumocytoma) and malignant tumors (eg. Papillary adenocarcinomas, papillary carcinoid, or alveolar adenoma). In some cases, lobectomy or surgical resection is performed. However, there are also case reports of serial radiographic monitoring or repeat biopsies over a 6 year period not showing evidence of disease progression. Recurrence or metastasis has never been reported. CONCLUSIONS: In summary, papillary adenoma is an extremely rare, benign, pulmonary neoplasm that has a favorable prognosis. It is curable with surgical excision. However, optimal treatment is unknown as this entity demands further understanding of its clinical behavior. Reference #1: Cornejo KM et al., 2013.J Broncol Intervent Pulmonol 20(1):52-7 Reference #2: Dessy E et al., 2000. Virchows Arch 436(3):289-295 Reference #3: Lin XY et al., 2015. Diagn Pathol 10:190 DISCLOSURE: The following authors have nothing to disclose: Anna Kyu-K Khaing Chen, Michael Ayers, Ronald Evans No Product/Research Disclosure Information

Imprint cytologic and immunocytochemical findings of sclerosing pneumocytoma.

To the best of our knowledge, there is no description on immunocytochemical study of sclerosing pneumocytoma (SP) using a cell transfer method. In this article, we report imprint cytological and immunocytochemical findings of SP. Three cases of SP possessing both imprint cytological and histological materials were examined. All tumors showed well-defined margin grossly. On microscopic examination, the tumor consisted of surface and stromal round cells. Cytologically, surface and stromal round cells showed fragments or clusters of papillary configuration with low N/C ratio and cell clusters of small to medium-sized cells with high N/C ration. Immunocytochemically, surface cells showed the positive reaction for surfactant apoprotein A (SPA), but stromal round cell exhibited the negative reaction for SPA. Cytologists and pathologists should steadily recognize cytological findings of surface and stromal round cells of SP. Immunocytochemistry of SPA may be useful in the discrimination of both cells. Diagn. Cytopathol. 2017;45:274-278. © 2016 Wiley Periodicals, Inc.

Combination of Continuous Positive Airway Pressure and Air Reinflation during One-Lung Ventilation Attenuates Lung Injury Following Esophagectomy: A Randomized Clinical Trial

Background: One-lung ventilation (OLV) is routinely used in esophagectomy to facilitate surgery. Lung injury may be induced by a multiple-hit mechanism. The aim of this study was to determine whether combined intervention using continuous positive airway pressure (CPAP) and air reinflation can reduce lung injury after OLV. Methods: Patients scheduled for esophagectomy were enrolled in this prospective study. These patients were assigned randomly to four different groups. In the control group (N=24), the collapsed lung was reinflated with 80% oxygen. In the air reinflation group (N=25), room air was used to regain two-lung ventilation. In the CPAP group (N=24), 5 cm H2O CPAP was administered to the contralateral lung during OLV. In the CPAP+AIR group (N=24), the contralateral lung received CPAP during OLV, and room air was used for reinflation of the lung. Plasma malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8) levels were measured at baseline (10 minutes after two lung ventilation) and 3 hours after reinflation. Bronchoalveolar lavage fluid (BALF) was obtained 30 minutes after lung re-expansion for measurements of surfactant apoprotein A (SP-A) and surfactant apoprotein C (SP-C). Computerized tomography was used to precisely detect micro-atelectasis on the fourth postoperative day. Results: Compared with the control group, CPAP and combined intervention increased arterial oxygen pressure levels 60 minutes after OLV (164±43 vs. 217±43; 164±43 vs. 216±52, P<0.05). The plasma MDA level in the air reinflation group was lower and SOD level was higher than those in the control group 3 hours after lung reinflation (P<0.05). The CPAP group had a lower plasma IL-8 level, a less atelectasis and a higher SP-A level in BALF (P<0.05) as compared to the control group. In the CPAP+AIR group, the plasma levels of MDA, IL-6, and IL-8, and atelectatic area reduced (7.9±3.9% vs. 4.4%±3.3%, P<0.05), while levels of SOD, SP-A, and SP-C increased (P<0.05) when compared with the control group. Conclusions: CPAP combined with air reinflation increased arterial oxygen pressure levels during OLV, reduced oxidative stress and inflammation, and minimized atelectasis following esophagectomy. Citation: Mao-Hua Wang, Guang-Xiang Chen, Ru-Rong Wang, Yun-Fei Wu, Jia-Li Wu, Xiao-Xia Duan. Combination of continuous positive airway pressure and air reinflation during one-lung ventilation attenuates lung injury following esophagectomy: a randomized clinical trial. J Anesth Perioper Med 2014; 1: 5-14. doi: 10.24015/JAPM.2014.0003 This is an open-access article, published by Evidence Based Communications (EBC). This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium or format for any lawful purpose. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Carcinoma bronquíolo-alveolar difuso em um cão: aspectos clínico-patológicos e imuno-histoquímicos

Um cão Poodle, 12 anos de idade, demonstrou marcada dispneia. Na radiografia, havia comprometimento difuso do pulmão e foi feito diagnóstico de pneumonia intersticial. Na necropsia, o pulmão continha múltiplos e pequenos nódulos coalescentes. Histologicamente, os nódulos eram compostos por células epiteliais cuboides ou colunares baixas atípicas, que eram PAS-negativa. A avaliação imuno-histoquímica revelou positividade para citoceratina, fator 1 de transcrição da tireoide (TTF-1) e apoproteína A surfactante (SP-A). O tumor foi negativo para vimentina e cromogranina A. As áreas necróticas não marcaram para TTF-1 e SP-A. Com base nos achados histopatológicos e imuno-histoquímicos, foi realizado o diagnóstico de carcinoma bronquíolo-alveolar não mucinoso com envolvimento difuso do pulmão. Essa é uma forma rara de apresentação desse tumor que pode mimetizar pneumonia na avaliação clínica e radiográfica. O diagnóstico definitivo é baseado na histopatologia e imuno-histoquímica.

Sudden death due to a hypopharyngeal mass during sleep: A case report

It is not frequent to find during the autopsy a lymphoid hyperplasia located in the hypopharynx. The literature reports numerous cases characterized by the presence of a mass, non-malignant too, in this particular anatomical district; in these cases the neoformation plays an important role in explaining the cause of death through different asphyxial mechanisms. We present a case of a 44-year-old man, in apparent good health, who suddenly died during sleep. The autopsy revealed an hypopharyngeal lymphoid hyperplasia that can provide the asphyxial mechanisms as cause of death. Furthermore, the anatomical finding could be integrated by a circumstantial piece of evidence: the death occurring during sleep. Some studies, in fact, have highlighted the physio-pathological mechanisms to explain sleep-disordered breathing, particularly the muscular and neural changes involving the pharynx. The asphyxial mechanism was also studied by an immunoistochemical analysis with the anti-Human Surfactant Apoprotein-A (SP-A) antibody.

NONHOMOGENEOUS IMMUNOSTAINING OF HYALINE MEMBRANES IN DIFFERENT MANIFESTATIONS OF DIFFUSE ALVEOLAR DAMAGE

To determine the nature of hyaline membranes in different manifestations of diffuse alveolar damage, [pulmonary and extrapulmonary acute respiratory distress syndrome], and idiopathic [acute interstitial pneumonia]. Pulmonary specimens were obtained from 17 patients with acute respiratory distress syndrome and 9 patients with acute interstitial pneumonia. They were separated into 3 different groups: (a) pulmonary diffuse alveolar damage (pDAD) (n = 8), consisting only of pneumonia cases; (b) extrapulmonary diffuse alveolar damage (expDAI) (n = 9), consisting of sepsis and septic shock cases; and (c) idiopathic diffuse alveolar damage (iDAD) (n = 9), consisting of idiopathic cases (acute interstitial pneumonia). Hyaline membranes, the hallmark of the diffuse alveolar damage histological pattern, were examined using various kinds of antibodies. The antibodies used were against surfactant apoprotein-A (SP-A), cytokeratin 7 (CK7), cytokeratin 8 (CK8), alpha smooth muscle actin (alpha-SMA), cytokeratin AE1/AE3 (AE1/AE3), and factor VIII-related antigen (factor VIII). Pulmonary diffuse alveolar damage showed the largest quantity of hyaline membranes (12.65% +/- 3.24%), while extrapulmonary diffuse alveolar damage (9.52% +/- 3.64%) and idiopathic diffuse alveolar damage (7.34% +/- 2.11%) showed intermediate and lower amounts, respectively, with the difference being statistically significant between pulmonary and idiopathic diffuse alveolar damage (P < 0.05). No significant difference was found for hyaline membranes Sp-A immunostaining among pulmonary (15.36% +/- 3.12%), extrapulmonary (16.12% +/- 4.58%), and idiopathic (13.74 +/- 4.20%) diffuse alveolar damage groups. Regarding factor VIII, we found that idiopathic diffuse alveolar damage presented larger amounts of immunostained hyaline membranes (14.12% +/- 6.25%) than extrapulmonary diffuse alveolar damage (3.93% +/- 2.86%), with this difference being statistically significant (P < 0.001). Equally significant was the difference for progressive decrease of cytokeratin AE1/AE3 immunostaining in hyaline membranes present in the extrapulmonary diffuse alveolar damage (5.42% +/- 2.80%) and idiopathic diffuse alveolar damage (0.47% +/- 0.81%) groups (P < 0.001). None of the groups stained for cytokeratin CK-7, CK-8, vimentin, or a anti-smooth muscle actin. This study showed that only the epithelial/endothelial components (SP-A, factor VIII, and AE1/AE3) of the alveolar/capillary barrier are present in hyaline membranes formation in the 3 groups of patients with diffuse alveolar damage. The significant difference in the expression of factor VIII-related antigen and cytokeratin AE1/AE3 in the expDA versus iDAD groups as well as the significant difference in the amount of hyaline membranes present in the pDAD versus iDAD groups are suggestive of a local and specific lesion with different pathways (direct, indirect, or idiopathic), depending on the type of diffuse alveolar damage.

Pulmonary adenocarcinoma with micropapillary component: an immunohistochemical study

Micropapillary carcinoma has been described in various organs, including the breast, urinary bladder, ovary and lung. We here present a case of pulmonary micropapillary carcinoma in a 72-year-old Japanese man who died of respiratory failure and septic shock, following which autopsy was performed. A mass measuring 2.5 x 2.5 x 2.5 cm was observed in the left lower lobe of the lung. The tumor showed moderately differentiated papillary adenocarcinoma with a focal micropapillary component. Carcinomatous lymphangiosis was also observed in the left lung and metastatic lesions were observed in the bilateral lung, liver, vertebra, muscle layer of the urinary bladder, right adrenal gland, spleen and lymph nodes. The micropapillary component was predominant at some metastatic sites. Immunohistochemically, both the adenocarcinoma and micropapillary components were positive for cytokeratin (CK) 7, CK19, TTF (thyroid transcription factor)-1, carcinoembryonic antigen (CEA) and surfactant apoprotein A (SP-A), and negative for CK20, estrogen receptor, progesterone receptor, uroplakin III, and CA125. The invasive area of the conventional adenocarcinoma component contained a large number of myofibroblasts, whereas the stroma of the micropapillary component contained a small number of myofibroblasts. However, no myofibroblasts were observed in the stroma of the central core of the non-invasive micropapillary carcinoma. Several lymphatic invasions by neoplastic cells were identified in the peripheral area of the micropapillary component using D2-40 antibody. The immunohistochemical profile may be helpful in determining the primary location of the neoplasm containing micropapillary features. Myofibroblasts are present in the stroma of the invasive neoplastic nests in the micropapillary component as well as the conventional adenocarcinoma component, and D2-40 monoclonal antibody may be useful for evaluating the lymphatic invasion of pulmonary micropapillary carcinoma.

Pulmonary Adenocarcinomas With Enteric Differentiation

Primary pulmonary adenocarcinomas with enteric differentiation (PAED) are mainly composed of tall-columnar cells that show similarity to intestinal epithelia and colorectal carcinomas. In this study, we analyzed the immunostaining profiles of 7 PAEDs in comparison with 14 metastatic colorectal carcinomas (MCRs) and 30 usual pulmonary adenocarcinomas (PACs), using antibodies against CDX-2, cytokeratin 7 (CK7), cytokeratin 20 (CK20), TTF-1, surfactant apoprotein-A (SP-A), Napsin A, and MUC2. The positive rates for CDX-2, CK7, CK20, TTF-1, SP-A, Napsin A, and MUC2 were 71%, 100%, 43%, 43%, 14%, 0%, and 43%, respectively, in the PAEDs; 100%, 0%, 86%, 0%, 0%, 0%, and 57% in the MCRs; 3%, 100%, 0%, 93%, 73%, 90%, and 0% in PACs. As expected, immunoreactivity of CDX-2, CK20, and MUC2 was detected in PAEDs. The observed decrease or loss of immunoreactivity for TTF-1, SP-A, and Napsin A indicates that these lesions demonstrate a shift away from their pulmonary phenotype, although CK7 expression was retained. The results indicate that CK7 and CK20 may be useful markers for distinction of PAEDs from MCRs.

Preservation of the Characteristics of the Cultured Human Type II Alveolar Epithelial Cells

The human type II alveolar epithelial cells lost their specific characteristics during cultivation. We examined the ultrastructural and biochemical nature of the human type II cells cultured by two culture systems. To make a physiological alveoli model, the epithelial cells were seeded onto the cell culture insert and allowed contact with the air directly. The cells exposed to the air expressed polarity and immature lamellar bodies in their cytoplasm. Separately, the alveolar epithelial cells were cultured as spheroids to construct the three-dimensional condition. These cells expressed mature morphological characteristics as epithelial cells and lamellar bodies. The expression of the surfactant apoprotein-A (SP-A) and -C (SP-C) mRNA was compared in the cells cultured as a monolayer, the air exposed and the spheroids. SP-A mRNA was detected in all the cultured epithelial cells, but SP-C mRNA, a specific protein for the type II cells, was expressed only in the cells forming spheroids. The expression of uPA, one of the fibrinolytic enzymes, its receptor (uPAR) and its inhibitor-1 (PAI-1) were also examined. The epithelial cells exposed to the air and formed spheroids expressed a larger amount of uPA mRNA than the monolayer, although the amount of uPAR mRNA were comparable in these cells. The amount of PAI-1 mRNA significantly increased when the epithelial cells were exposed to the air. These results indicate that the type II alveolar epithelial cells induced and preserved their specific characteristics by taking the physiological three-dimensional structure, and these characteristics were partially restored by exposure to the air. Those findings suggest that the alveolar epithelial cells should be cultivated in three-dimensional form with contact to the air to regenerate an appropriate alveolar tissue.

Increased expression of 11 beta-hydroxysteroid dehydrogenase type 2 in the lungs of patients with acute respiratory distress syndrome.

We examined the immunohistochemical distribution of 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta-HSD2), the enzyme responsible for the conversion of bioactive glucocorticoids to their receptor-inactive forms, in lung tissue obtained at autopsy from 14 patients who had died due to acute respiratory distress syndrome (ARDS). We found positive immunoreactivity for 11 beta-HSD2 in 13 cases. The cells expressing 11 beta-HSD2 in the alveolar wall were positive for surfactant apoprotein-A as well as cytokeratin. Immunoreactivity for 11 beta-HSD2 was also detected in the CD68+ cells, which were found in the alveolar spaces. All patients had been treated with glucocorticoids for ARDS and/or the underlying diseases. There was no statistically significant correlation between the use of glucocorticoids and 11 beta-HSD2 immunoreactivity in the alveolar wall (P = 0.0729). However, expression of grade + + was found in three out of five patients who received dexamethasone pulse therapy at relatively large doses, as well as in three other patients treated with prednisolone for a long period of time for the underlying disease. An increase in the expression of 11 beta-HSD2 may result in faster glucocorticoid breakdown in lung cells in patients with ARDS. Impaired glucocorticoid availability in the lungs of such patients may explain, in part, the fact that glucocorticoid therapy does not always rescue patients with ARDS.

Immunohistochemical Distribution of Surfactant Apoprotein-A in Congenital Diaphragmatic Hernia-II

Morphometric analyses of the immunohistochemical expression of surfactant apoprotein A (SP-A) were carried out on the bronchioles of human congenital diaphragmatic hernia (CDH) neonates and then compared with those in a gestational and postnatal age-matched control group. There was no difference in SP-A expression between lung specimens of the control group and unaffected lungs in the CDH group. However, compared with both these lungs, the ipsilateral lungs of the CDH group showed a significant increase in SP-A expression, namely, the number of SP-A-positive cells per bronchiole, the number of SP-A-positive cells per unit perimeter of bronchiole, and the number of SP-A-positive cells per unit bronchiolar surface area. These results suggest that in lungs of CDH cases, especially ipsilateral lungs, there is a possible delay in the functional maturation or development of SP-A synthesis by the bronchiole, and this retardation may play a role in the postnatal respiratory insufficiency observed in CDH patients.

Donor lung pretreatment with surfactant in experimental transplantation preserves graft hemodynamics and alveolar morphology.

In experimental lung transplantation, the reduction of endogenous surfactant properties occurs after graft preservation and transplant reperfusion. The aim of this study was to evaluate the efficacy of donor lung pretreatment with exogenous surfactant on graft damage after ischemia and reperfusion. Fourteen (control group A, n = 8; study group B, n= 6) young female white pigs (mean weight 27 +/- 3.5 kg) were used in a newly developed autotransplantation model within situcold ischemia. In study group B, before thoracotomy, 1.5 ml/kg surfactant apoprotein-A-free surfactant was administrated into the left main bronchus via flexible bronchoscopy. Belzer UW solution was used for lung preservation. Cold ischemia was achieved for 3 hr with interlobar lung parenchyma temperature at 8 +/- 1.3 degrees C, and central temperature maintained at 37.20 +/- 0.5 degrees C. Animals were sacrificed after 3 hr of graft reperfusion. At the end of reperfusion, pulmonary vascular resistance index (was 447.80 dyn/sec.cm(5).m(2)(+/-66.8) in group A vs 249.51 in group B (P< 0.001) and serum nitric oxide was adequately preserved. The mean alveolar surface area estimated by computerized morphometry was 5280.84 (4991.1) microm(2)(group A) vs 3997.89 (3284.70) microm(2)(group B;P< 0.005). Histology revealed milder macrophage and lymphocyte infiltration in group B at the end of reperfusion. Pretreatment of donor lung with an surfactant apoprotein-A -free surfactant agent appears to be beneficial in terms of maintaining serum NO and reducing hemodynamic disturbances. Furthermore, alveolar histology and stereomorphology are better preserved.

Immunohistochemistry in the distinction between malignant mesothelioma and pulmonary adenocarcinoma: a critical evaluation of new antibodies

Aim: The value of immunohistochemical staining in differentiating between malignant mesothelioma and pulmonary adenocarcinoma was re-examined using newly available commercial antibodies, with the aim of increasing the sensitivity and specificity...

Surfactant apoprotein A modulates interleukin-8 and monocyte chemotactic peptide-1 production.

Previous studies have shown that surfactant apoprotein A (SP-A) and natural or synthetic surfactant can modulate the release of pro-inflammatory cytokines from alveolar mononuclear phagocytes. The aim of this study was to assess whether SP-A or Surfactant (Surf) from patients with pulmonary alveolar proteinosis (PAP) can affect the release of two chemokines (interleukin (IL)-8 and monocyte chemtactic peptide (MCP)-1) from human monocytes and rat lung type-II cells. In addition IL-8 and MCP-1 levels were assessed in the brochoalveolar lavage fluid (BALF) of seven patients with PAP and compared with those in a group of control subjects (n=5). SP-A, tested over a wide range of concentrations, significantly increased IL-8 and MCP-1 release from monocytes. SP-A retained its activity after collagenase digestion, but was not active after heat treatment. The release of IL-8 by monocytes was also stimulated by Surf. Finally, median BALF IL-8 and MCP-1 levels in PAP patients were significantly higher than in controls (9.50 and 9.51 pg x mL(-1) in controls versus 151.95 and 563.70 pg x mL(-1) in PAP, respectively) and significantly correlated with SP-A concentrations in BALF. Overall the results of this study support the view that the high content of alveolar surfactant apoprotein A may contribute to the upregulation of chemokine release in pulmonary alveolar proteinosis, thus contributing to airway inflammation.

Value of thyroid transcription factor-1 and surfactant apoprotein A in the differential diagnosis of pulmonary carcinomas: a study of 109 cases.

Thyroid transcription factor-1 (TTF-1) and surfactant apoprotein A (SP-A) belong to tissue-specific markers expressed in the normal respiratory epithelium. Both proteins are expressed in some lung carcinomas, and they have potential diagnostic use. We performed an immunohistochemical study on 109 tumors to determine the usefulness of monoclonal SP-A (PE-10) and TTF-1 (8G7G3/1) antibodies in distinguishing primary and metastatic lung carcinomas ( n=54) from a broad spectrum of nonpulmonary tumors ( n=55). An immunoperoxidase method using a streptavidin-biotin kit was applied on paraffin sections. We found positive results for TTF-1 and SP-A in 75% and 46% of pulmonary adenocarcinomas and in 50% and 25% of pulmonary non-neuroendocrine large cell carcinomas (LCCs), respectively. Small cell lung carcinomas were TTF-1 positive in 89% of cases and completely negative for SP-A. Squamous cell carcinomas and carcinoid tumors were negative for both proteins. In the group of nonpulmonary tumors, TTF-1 was detected in 8 of 11 thyroid carcinomas and SP-A in 1 of 6 colorectal carcinomas. Other tumors, including seven cases of pleural mesothelioma, were negative for both TTF-1 and SP-A. The expression of both antibodies was independent of primary and metastatic sites of the tumor. We observed a significant decrease of SP-A immunoreactivity in poorly differentiated lung adenocarcinomas. The combination of anti-TTF-1 with anti-SP-A does not increase the diagnostic usefulness of TTF-1 alone. Because of its diagnostic utility TTF-1 should be added to a panel of antibodies used for assessing tumors of unknown origin.

Novel approach to quantitative reverse transcription PCR assay of mRNA component in autopsy material using the TaqMan fluorogenic detection system: dynamics of pulmonary surfactant apoprotein A

A novel approach to quantitative reverse transcription (RT)-PCR assay of mRNA component using fluorescent TaqMan methodology and a new instrument (ABI Prism 7700 sequence detection system) was developed for autopsy materials. Pulmonary surfactant apoprotein A (SP-A) mRNA from a cadaveric lung was quantitated in real-time. The target SP-A gene and the endogenous reference of glyceraldehyde-3-phosphate (GAPDH) were amplified in the same tube, and an amount of the target was normalized to the reference. This assay had a high reproducibility and discrimination even in forensic autopsy materials up to 96 h postmortem. Elevated SP-A expressions were determined in some cases. This system without post-PCR sample handling would be a very useful tool in pathological diagnosis and DNA analysis.

Immunohistochemistry of pulmonary surfactant apoprotein A in forensic autopsy: reassessment in relation to the causes of death

To reassess the immunohistochemical distribution of pulmonary surfactant apoprotein A (SP-A) in relation to the causes of death, 282 forensic autopsy cases were reviewed. The most intense and dense granular immunostaining of intra-alveolar SP-A was observed in the hyaline membrane syndrome from various traumas, protracted death from drowning, and perinatal aspiration of amniotic fluid. Similar granular staining pattern was found in fatal poisoning by a muscle relaxant and organophosphate pesticides. An evident increase of intra-alveolar granular staining was noted in most fatalities from mechanical asphyxia and drowning, and some cases of fire death. SP-A staining was usually very weak or sparse in alcohol intoxication, poisoning by hypnotics and also carbon monoxide poisoning. These findings suggest that the amount of intra-alveolar granular SP-A staining may be a possible indicator of severity and duration of respiratory distress (agony) from peripheral (non-central nervous system) origin and alveolar damage.

Surfactant protein A prevents silica-mediated toxicity to rat alveolar macrophages.

Silicosis is a serious occupational lung disease associated with irreversible pulmonary fibrosis. The interaction between inhaled crystalline silica and the alveolar macrophage (AM) is thought to be a key event in the development of silicosis and fibrosis. Silica can cause direct injury to AMs and can induce AMs to release various inflammatory mediators. Acute silicosis is also characterized by a marked elevation in surfactant apoprotein A (SP-A); however, the role of SP-A in silicosis is unknown. We investigated whether SP-A directly affects the response of AMs to silica. In this study, the degree of silica toxicity to cultured rat AMs as assessed by a (51)Cr cytotoxicity assay was shown to be dependent on the time of exposure and the concentration and size of the silica particles. Silica directly injured rat AMs as evidenced by a cytotoxic index of 32.9 +/- 2.5, whereas the addition of rat SP-A (5 microg/ml) significantly reduced the cytotoxic index to 16.6 +/- 1.2 (P < 0. 001). This effect was reversed when SP-A was incubated with either polyclonal rabbit anti-rat SP-A antibody or D-mannose. These data indicate that SP-A mitigates the effect of silica on AM viability, and this effect may involve the carbohydrate recognition domain of SP-A. The elevation of SP-A in acute silicosis may serve as a normal host response to prevent lung cell injury after exposure to silica.

Monitoring alveolar epithelial function in acute lung injury.

Identification of humoral markers of acute lung injury may lead to insights into pathologic mechanisms. In addition, specific markers may be useful for predicting development of acute respiratory distress syndrome (ARDS) or for assessing prognosis. Ultimately, studies of lung injury markers may help define interventions that prevent or moderate ARDS. The alveolar epithelium is important both for the integrity of the blood-gas barrier and for repair of the barrier after lung injury. This article reviews markers that derive from or relate to the alveolar epithelium and that might be used for monitoring alveolar epithelial function in acute lung injury. Surfactant apoproteins may be important markers of injury or for prognosis. Levels of surfactant apoprotein A (SP-A) fall 50-75% in patients with severe lung injury compared to normal patients. Serum levels of SP-A in patients dying of acute respiratory distress syndrome are double serum levels of survivors.

Biophysical characterization and modeling of lung surfactant components.

The present study characterizes the dynamic interfacial properties of calf lung surfactant (CLS) and samples reconstituted in a stepwise fashion from phospholipid (PL), hydrophobic apoprotein (HA), surfactant apoprotein A (SP-A), and neutral lipid fractions. Dipalmitoylphosphatidylcholine (DPPC), the major PL component of surfactant, was examined for comparison. Surface tension was measured over a range of oscillation frequencies (1-100 cycles/min) and bulk phase concentrations (0.01-1 mg/ml) by using a pulsating bubble surfactometer. Distinct differences in behavior were seen between samples. These differences were interpreted by using a previously validated model of surfactant adsorption kinetics that describes function in terms of 1) adsorption rate coefficient (k1), 2) desorption rate coefficient (k2), 3) minimum equilibrium surface tension (gamma*), 4) minimum surface tension at film collapse (gammamin), and 5) change in surface tension with interfacial area for gamma < gamma* (m2). Results show that DPPC and PL have k1 and k2 values several orders of magnitude lower than CLS. PL had a gammamin of 19-20 dyn/cm, significantly greater than CLS (nearly zero). Addition of the HA to PL restored dynamic interfacial behavior to nearly that of CLS. However, m2 remained at a reduced level. Addition of the SP-A to PL + HA restored m2 to a level similar to that of CLS. No further improvement in function occurred with the addition of the neutral lipid. These results support prior studies that show addition of HA to the PL markedly increases adsorption and film stability. However, SP-A is required to completely normalize dynamic behavior.