Hepatic gas gangrene following orthotopic liver transplantation: three cases treated with re-transplantation and a review of the literature.

Gas gangrene is a rare and devastating infectious process that can occur after liver transplantation, most often following hepatic artery thrombosis. We here report 3 cases of gas gangrene following orthotopic liver transplantation. Blood cultures were positive for Clostridium clostridiiforme in one case. In 2 other cases liver tissue from explanted specimens was positive for Enterobacter cloacae. Ultrasound demonstrated hepatic artery thrombosis and computed tomography imaging revealed diffuse liver necrosis with gas formation in each case. All 3 patients were successfully treated with a combination of antibiotics and emergent re-transplantation. We review previously published cases of gas gangrene after liver transplant and emphasize the importance of hepatic artery thrombosis in the development of this syndrome as well as the frequent involvement of non-clostridial organisms. Early diagnosis and aggressive combined medical and surgical treatment including re-transplantation are essential for successful treatment of these rare and catastrophic infections.

Endoscopic ablation of intestinal metaplasia containing high-grade dysplasia in esophagectomy patients using a balloon-based ablation system.

BACKGROUND: This study aimed to determine the optimal treatment parameters for the ablation of intestinal metaplasia (IM) containing high-grade dysplasia (HGD) using a balloon-based ablation system for patients undergoing esophagectomy. METHODS: Immediately before esophagectomy, patients underwent ablation of circumferential segments of the esophagus containing IM-HGD using the HALO360 system. The treatment settings were randomized to 10, 12, or 14 J/cm2 for two, three, or four applications. After esophagectomy, multiple sections from ablation zones were microscopically evaluated. Histologic end points included maximum ablation depth (histologic layer) and complete ablation of all IM-HGD (yes/no). RESULTS: Eight men with a mean age of 57 years (range, 45-71 years) were treated, and 10 treatment zones were created. There were no device-related adverse events. At resection, there was no evidence of a transmural thermal effect. Grossly, ablation zones were clearly demarcated sections of ablated epithelium. The maximum ablation depth was the lamina propria or muscularis mucosae. The highest energy (14 J/cm2, 4 applications) incurred edema in the superficial submucosa, but no submucosa ablation. Complete ablation of IM and HGD occurred in 9 of 10 ablation zones (90%), defined as complete removal of the epithelium with only small foci of "ghost cells" representing nonviable, ablated IM-HGD and demonstrating loss of nuclei and cytoarchitectural derangement. One focal area of viable IM-HGD remained at the margin of one ablation zone (12 J/cm2, 2 applications) because of incomplete overlap. CONCLUSION: Complete ablation of IM-HGD without ablation of submucosa is possible using the HALO360 system. Ablation depth is dose related and limited to the muscularis mucosae. In one patient, small residual foci of IM-HGD at the edge of the ablation zone were attributable to incomplete overlap, which can be avoided. This study, together with nonesophagectomy IM-HGD trials currently underway, will identify the optimal treatment parameters for IM-HGD patients who would otherwise undergo esophagectomy or photodynamic therapy.

Thin-layer ablation of human esophageal epithelium using a bipolar radiofrequency balloon device.

BACKGROUND: The goal of this study was to determine the optimal treatment parameters for the ablation of human esophageal epithelium using a balloon-based bipolar radiofrequency (RF) energy electrode. METHODS: Immediately prior to esophagectomy, subjects underwent esophagoscopy and ablation of two separate, 3-cm long, circumferential segments of non-tumor-bearing esophageal epithelium using a balloon-based bipolar RF energy electrode (BARRX Medical, Inc., Sunnyvale, CA, USA). Subjects were randomized to one of three energy density groups: 8, 10, or 12 J/cm2. RF energy was applied one time (1x) proximally and two times (2x) distally. Following resection, sections from each ablation zone were evaluated using H&E and diaphorase. Histological endpoints were complete epithelial ablation (yes/no), maximum ablation depth, and residual ablation thickness after tissue slough. Outcomes were compared according to energy density group and 1x vs 2x treatment. RESULTS: Thirteen male subjects (age, 49-85 years) with esophageal adenocarcinoma underwent the ablation procedure followed by total esophagectomy. Complete epithelial removal occurred in the following zones: 10 J/cm2 (2x) and 12 J/cm2 (1x and 2x). The maximum depth of injury was the muscularis mucosae: 10 and 12 J/cm2 (both 2x). A second treatment (2x) did not significantly increase the depth of injury. Maximum thickness of residual ablation after tissue slough was only 35 microm. CONCLUSIONS: Complete removal of the esophageal epithelium without injury to the submucosa or muscularis propria is possible using this balloon-based RF electrode at 10 J/cm2 (2x) or 12 J/cm2 (1x or 2x). A second application (2x) does not significantly increase ablation depth. These data have been used to select the appropriate settings for treating intestinal metaplasia in trials currently under way.

The impact of nonalcoholic fatty liver disease and the metabolic syndrome on progression of fibrosis in patients with recurrent HCV after liver transplantation.

Nonalcoholic fatty liver disease (NAFLD) and the metabolic syndrome (MS) have been shown to play a role in disease progression and response to therapy in patients with chronic hepatitis C virus (HCV) infection. The primary objective of this study was to evaluate the impact of coexisting NAFLD and MS on the progression of fibrosis in patients with recurrent HCV treated with interferon (IFN)/ribavirin after orthotopic liver transplantation (OLT). From 1998 to 2004, a total of 418 patients underwent OLT in our center for HCV-related cirrhosis. Thirty-five patients with recurrent HCV on IFN/ribavirin treatment, who had at least 2 posttransplant liver biopsies at least 6 months apart, were included in the study. Patients who had MS at the time of their first posttransplant biopsy were identified. The first and last posttransplant biopsies were assessed for the presence and severity of NAFLD, grade of inflammation, and stage of fibrosis. The fibrosis progression rate (FPR) was calculated and expressed in fibrosis units per month (FU/mo). Among 35 patients, 34% were diagnosed with NAFLD in the first posttransplant biopsy. The mean FPR was 0.05+/-0.16 FU/mo in the presence of NAFLD compared to 0.07+/-0.10 FU/mo in its absence (P=.68) and 0.03+/-0.06 FU/mo in the presence of MS versus 0.10+/-0.15 FU/mo in its absence (P=.06). When FPR values were divided into two categories of <0.16 FU/mo or >or=0.16 FU/mo (below/above the 25% upper quartile) or <0.08 FU/mo or >or=0.08 FU/mo (below/above the 50% upper quartile), there was no correlation between FPR categories and the presence of NAFLD with or without MS, only MS, or the absence of both in the first liver transplant biopsy (P=.13). Coexisting NAFLD or MS had no significant effect on the progression of fibrosis after OLT in patients with treated hepatitis C after OLT.

Histochemical and immunohistochemical characterization of foamy histiocytes (muciphages and xanthelasma) of the rectum.

Despite being relatively common in the rectum, foamy histiocytes have received scant attention as to the antecedent lesion that causes them to form or their histologic characterization on the types of muco-substances they accumulate. One-hundred consecutive tissue sections of the rectum from an equal number of patients were reviewed for the presence of foamy histiocytes, evaluated for their associated histologic features, and examined histochemically for five types of mucin. Immunohistochemical and electron microscopic studies were performed. Forty (40%) of the rectal biopsy tissues contained foamy histiocytes. Patients presented with diarrhea, hematochezia, intestinal habit change, constipation, hemorrhoids, and abdominal pain. Endoscopically, 19 patients were thought to have rectal nodules or polyps. Histologically, 25 of the patients had regenerative changes in the adjacent mucosa and 14 had hyperplastic changes. In 36 patients (90%), the foamy histiocytes were located superficially in the lamina propria. Associated changes indicated that they are found in areas that are subject to an injury that is in a healing phase. These changes included mild fibrosis and chronic inflammation of lamina propria with mild architectural distortion. Thirty-five (88%) cases showed staining for D-PAS, Alcian blue stain pH 2.5, and the cocktail Alcian blue stain/PAS. Mucicarmine was positive in 25 (63%) cases. The Alcian blue stain pH 1.0 was positive in 19 (59%) of 32 cases. Ultrastructural studies showed electron-dense globules. Two cases were histologically identical to the other 38 but they did not stain for any mucin. Ultrastructural features disclosed clear vacuoles and thus represent a xanthelasma of the rectum. The foamy cells in all cases were confirmed to be histiocytes by immunohistochemistry and electron microscopy. Although muciphages and xanthelasma of the rectum may mimic polyps endoscopically, they are not related to any specific symptom or clinical finding, despite the fact that they probably represent remnants of a previous injury. Muciphages contain neutral, weakly acidic or strongly acidic mucin. The main type of acidic mucin is sialomucin with a smaller component of sulfated mucin.

Use of low-dose OKT3 as induction therapy in liver transplantation.

BACKGROUND: A pilot study was performed to prospectively evaluate the safety and efficacy of "low-dose" OKT3 induction after liver transplantation. METHODS: Sixteen patients received a 5- to 10-day course of OKT3 (2.5 mg i.v. daily) along with azathioprine, prednisone, and the delayed introduction of cyclosporine (Neoral). RESULTS: Patient and graft survival rates at 1 year were 88% and 82%. Five patients (31%) had biopsy-proven rejection; all five were treated successfully with steroids. There were 15 infections in 12 patients, including 5 cytomegalovirus infections. Adverse events attributed to OKT3 consisted of low-grade fever (five patients), transient hypoxemia (three patients), and transient hypotension (two patients). Pharmacy acquisition costs for OKT3 averaged $2,139 less as compared to a group of historical controls receiving full-dose therapy. CONCLUSIONS: Low-dose OKT3 induction appears to be a safe and useful method of postoperative immunosuppression after liver transplantation. Its ultimate clinical, immunologic, and economic efficacy awaits determination by randomized trial.

Isolated lung transplantation in children: pathological diagnosis and incidence of pulmonary complications.

The pathological findings in the allografts of 14 children who underwent lung transplantation (LT) at St. Louis Children's Hospital, St. Louis, MO, in the period between July 1990 and May 1992 were reviewed. The study is based on histological analysis of 63 transbronchial biopsy (TBB) specimens, eight open lung biopsy specimens, and three pneumonectomy specimens. The mean age at transplantation was 10.5 years (range, 1 to 17 years) and the average follow-up period was 5.7 months. Sufficient tissue for an adequate pathological examination was obtained in 58 (92%) TBB specimens. Each specimen consisted of a mean of 6.12 tissue fragments, but only 4.79 fragments contained actual lung parenchyma for suitable examination. Ten patients (71%) had 23 biopsy-proven episodes of acute rejection with a frequency of 1.64 episodes per patient. The first episode was documented at a mean of 19 days after transplantation. Six patients (42.8%) developed bronchiolitis obliterans (BO). The definitive diagnosis of this condition was made either by open lung biopsy (n = 3) or on allograft pneumonectomy (n = 1), and it was infrequently recognized by TBB. Four of the six patients died less than 9 months after the diagnosis of BO was made, indicating the grave consequences of this complication. Two other deaths were attributed to the development of posttransplantation lymphoproliferative disorders.

Infected epidermoid cyst of the sphenoid bone.

An infected epidermoid cyst presented on CT as a primarily dense, sclerotic expansile lesion in the greater wing of the sphenoid bone. Presumably, infection was responsible for the atypical appearance.

Thyroid transcription factor-1, thyroglobulin, cytokeratin 7, and cytokeratin 20 in thyroid neoplasms.

Thyroid transcription factor-1 (TTF-1), a member of the NKx2 family of homeodomain transcription factors, is a mediator of thyroid-specific transcription of the thyroglobulin (TG) gene. The combined immunohistochemical profile of TTF-1, TG, cytokeratin 7 (CK7), and cytokeratin 20 (CK20) in neoplasms of the thyroid gland and their metastases to other sites has not been defined previously. Formalin-fixed tissue of 43 thyroid tumors, including 31 carcinomas and 12 adenomas, and 16 metastasic lesions were immunostained using monoclonal antibodies to TTF-1, TG, CK7, and CK20. Immunoreactivity of the primary tumors (adenomas and carcinomas) for TTF-1 was seen in 32 cases (74%), TG 32 (74%), and CK7 34 (79%), whereas none (0%) showed positivity for CK20. The distribution of reactivity in the 31 carcinomas for TTF-1, TG, and CK7, respectively was papillary (8/8), (8/8), and (8/8); poorly differentiated (6/7), (4/7), and (6/7); oncocytic (Hürthle) cell (2/6), (6/6), and (4/6); follicular (4/4), (3/4), and (3/4); medullary (1/2), (0/2), and (1/2). One of four anaplastic carcinomas was focally immunoreactive showing positivity for TTF-1 only. Of the six follicular adenomas, five were positive for TTF-1, six for TG, and six for CK7. Among the six oncocytic cell adenomas, five were reactive for TTF-1, five for TG, and all six for CK7. Twelve (75%) of the 16 metastatic tumors were positive for TTF-1, 10 (63%) for TG, 15 (94%) for CK7, and none (0%) for CK20. In summary, TTF-1 and TG are demonstrable by immunohistochemistry in the majority of thyroid neoplasms. Compared with TG, an antibody to TTF-I is a similarly sensitive marker for thyroid tumors. Moreover, TTF-1 is a more sensitive marker for poorly differentiated carcinomas and metastasis. In most cases, its nuclear pattern of immunoreactivity facilitates interpretation. Thyroid tumors are CK7+/CK20-. The panel of antibodies for TG, TTF-1, CK7, and CK20 is useful when the thyroid origin of a metastatic tumor is a consideration.

Overexpression of transforming growth factor-alpha and epidermal growth factor-receptor in idiopathic pulmonary fibrosis.

BACKGROUND AND AIM: A recent transgenic mouse model overexpressing transforming growth factor alpha (TGF-alpha) led to a phenotype of pulmonary fibrosis. In order to validate this mouse as a model for idiopathic pulmonary fibrosis in humans, we studied the expression of TGF-alpha in lung tissue of patients with idiopathic pulmonary fibrosis compared to control lung tissue. METHODS: Tissue from both groups was obtained from operative specimens and immediately formalin-fixed and paraffin embedded. Contiguous four micron sections were prepared for conventional histochemical staining and staining with antibodies to either TGF-alpha or the epidermal growth factor-receptor (EGF-R). Immunostaining was performed using the Ventana ES automated immunohistochemistry system. Four cell types were examined (vascular endothelium, bronchial epithelium, type 2 pneumocytes, and fibroblasts) and stain activity was scored on a six point scale. RESULTS: Eleven patients with IPF were compared to seven control subjects. TGF-alpha immunoreactivity was significantly higher in the IPF patients than in controls in the vascular endothelium, type 2 pneumocytes, and fibroblasts (P < 0.005). [IPF (4(2-4) Median (Range)) than the controls (0.5(0-2), p < 0.0005).] The differences in EGF-R, one of the receptors for TGF-alpha, between these two patient populations were not as striking. There was a small but significantly greater expression of EGF-R in the bronchial epithelium and type 2 pneumocytes of the IPF patients. CONCLUSIONS: TGF-alpha is overexpressed in patients with IPF, especially in the vascular endothelial cells.

Metastatic female adnexal tumor of probable Wolffian origin: a case report and review of the literature.

Female adnexal tumor of probable wolffian origin is a rare neoplasm that can present diagnostic difficulties. We report herein a case of a 60-year-old woman with female adnexal tumor of probable wolffian origin arising within the leaves of a broad ligament and, 5 years later, presenting with metastasis to the liver. The morphologic, immunohistochemical, ultrastructural, and DNA ploidy findings of the original and metastatic tumor, differential diagnoses, and the results of the English-language literature review are presented.

Hyalinizing spindle cell tumor with giant rosettes--a soft tissue tumor with mesenchymal and neuroendocrine features. An immunohistochemical, ultrastructural, and cytogenetic analysis.

CONTEXT: Hyalinizing spindle cell tumor with giant rosettes is a recently described biphasic neoplasm of soft tissues that shares mesenchymal and neuroendocrine features. Its morphologic structure is distinctive, with the presence of hyalinized paucicellular foci that are termed rosettes. The cells around the latter display positive immunoreactivity for neuroendocrine markers. The small number of cases described to date indicates that they tend to be localized in the extremities. OBJECTIVE: To describe the clinicopathologic features of 2 unusual cases of hyalinizing spindle cell tumor with giant rosettes. METHODS AND RESULTS: One tumor was located in the prestyloid parapharyngeal space and the second in the left thigh. Both tumors were well circumscribed and surrounded by a thin capsule-like fibrous band without infiltrating projections. The rosettes were embedded in a spindle cell proliferation. Immunohistochemical stains showed positive results for S100 protein, synaptophysin, CD57, protein gene product 9.5, and neuron-specific enolase exclusively in the cells palisading the rosettes. These markers were negative in the spindle cell portions of the tumor. The latter were immunoreactive for factor XIIIa, vimentin, HAM56, collagen IV, and CD68. Vimentin was the only marker shared by the rosette-forming cells and the spindle cells. Ultrastructurally, the rosette-forming cells contained neurosecretory granules. This study describes the first cytogenetic analysis in this type of tumor revealing 2 cell lines, both containing a balanced translocation between chromosomes 7 and 16. Follow-up of the patients at 16 and 8 months did not disclose evidence of recurrence. CONCLUSIONS: These 2 new cases increase the awareness of hyalinizing spindle cell tumor with giant rosettes and demonstrate that it is a spindle cell neoplasm of unique cytogenetic rearrangements composed of dendritic, histiocytic, and fibroblastic cells admixed with cells that have neuroendocrine differentiation.

Thyroid transcription factor-1 and cytokeratins 7 and 20 in pulmonary and breast carcinoma.

OBJECTIVE: To evaluate the immunohistochemical expression of a lung epithelial gene transcription factor, thyroid transcription factor-1 (TTF-1), in lung and breast carcinoma in pulmonary cytologic preparations and to correlate the results with the expression of cytokeratin 7 (CK7) and 20 (CK20). STUDY DESIGN: Cell blocks of cytologic specimens were immunostained with antibodies to TTF-1, CK7 and CK20. Specimens included 41 primary lung carcinomas (21 adenocarcinomas, 8 squamous cell carcinomas and 12 small cell undifferentiated carcinomas) and 6 metastatic breast adenocarcinomas. RESULTS: The lung adenocarcinomas showed nuclear reactivity for TTF-1 in 76% (16/21) of the cases and a staining combination of CK7+/CK20- in 95% (20/21) of the cases. Only one case was CK7+/CK20+. All the breast carcinomas were nonreactive to TTF-1, and all were CK7+/CK20-. The squamous cell carcinomas and small cell undifferentiated carcinomas showed TTF-1 positivity in 38% (3/8) and 83% (10/12), respectively.

Monoclonal antibody to thyroid transcription factor-1: production, characterization, and usefulness in tumor diagnosis.

Thyroid transcription factor-1 (TTF-1), a member of the NKx2 family of homeodomain transcription factors, is expressed in epithelial cells of the thyroid gland and the lung. To produce monoclonal antibodies specific for TTF-1, the polypeptide was expressed in E. coli and purified utilizing affinity chromatography of a polyhistidine-tagged TTF-1 fusion protein. Splenocytes from BALB/c mice immunized with recombinant TTF-1 were fused with P3x/63Ag8.653 myeloma cells to produce hybridomas. Tissue culture supernatant was screened for anti TTF-1 activity by ELISA employing recombinant TTF-1 as antigen. Hybridomas producing high-affinity antibodies were subcloned by limiting dilution. Antibodies from tissue culture fluid from an IgG1 clone (8G7G3/1) that stained the nuclei of paraffin-embedded human thyroid tissues were precipitation-purified and further characterized. The antibody stained a single 40-kDa polypeptide in immunoblots of nuclear extracts or lysates of cell lines known to express TTF-1 mRNA. MAb 8G7G3/1 also stained nuclei of tissue in a highly specific manner consistent with the pattern of expression obtained with an established polyclonal TTF-1 antibody and by in situ hybridization. MAb 8G7G3/1 was used for TTF-1 immunohistochemistry of human adenocarcinomas of the lung, colon, and breast as well as small cell carcinomas of the lung. TTF-1 was detected in primary lung adenocarcinomas and small cell carcinomas and was absent in colon and breast carcinomas. These findings demonstrate that anti-TTF-1 MAb 8G7G3/1 specifically binds TTF-1 in cell extracts and tissues and can be used to distinguish between lung and nonlung origin of a tumor.

The hedgehog processing pathway is required for NSCLC growth and survival.

Considerable interest has been generated from the results of recent clinical trials using smoothened (SMO) antagonists to inhibit the growth of hedgehog (HH) signaling-dependent tumors. This interest is tempered by the discovery of SMO mutations mediating resistance, underscoring the rationale for developing therapeutic strategies that interrupt HH signaling at levels distinct from those inhibiting SMO function. Here, we demonstrate that HH-dependent non-small cell lung carcinoma (NSCLC) growth is sensitive to blockade of the HH pathway upstream of SMO, at the level of HH ligand processing. Individually, the use of different lentivirally delivered shRNA constructs targeting two functionally distinct HH-processing proteins, skinny hedgehog (SKN) or dispatched-1 (DISP-1), in NSCLC cell lines produced similar decreases in cell proliferation and increased cell death. Further, providing either an exogenous source of processed HH or a SMO agonist reverses these effects. The attenuation of HH processing, by knocking down either of these gene products, also abrogated tumor growth in mouse xenografts. Finally, we extended these findings to primary clinical specimens, showing that SKN is frequently overexpressed in NSCLC and that higher DISP-1 expression is associated with an unfavorable clinical outcome. Our results show a critical role for HH processing in HH-dependent tumors, identifies two potential druggable targets in the HH pathway, and suggest that similar therapeutic strategies could be explored to treat patients harboring HH ligand-dependent cancers.

Second opinion pathology in liver biopsy interpretation.

OBJECTIVE: Clinical management of liver diseases is often based on the interpretation of the pathologist examining liver biopsies. Many pathologists have little formal training and experience with these tissues. The magnitude of this problem is not determined yet. The goal of this study was to determine the diagnostic discrepancies that surfaced after a second opinion by experienced hepatopathologists interpreting liver biopsy tissues. METHODS: All 178 consecutive liver biopsy tissue glass slides provided to hepatology consultants in 1996 and 1997 were selected for evaluation. Specimens with neoplasms, transplant-related indications, or those specifically referred by a community-based pathologist for consultation were excluded. Diagnosis and interpretations were compared with the reports from the original institutions. Discordant interpretations were grouped in major (description or diagnosis that would change management decisions) and minor (not likely to alter management) categories. Monetary cost of the pathology studies was analyzed. RESULTS: A total of 125 specimens corresponding to 124 patients met inclusion criteria. Thirty-five (28%) and 47 (37.6%) biopsies had major and minor discrepancies, respectively. Full agreement was obtained in 43 (34.4%) cases. Fifteen (42.8%) of the major interpretation errors were on patients with chronic cholestatic disorders, nine (25.7%) with hepatocellular processes, and 11 (31.4%) were related to establishing the presence or absence of cirrhosis. Reviewing the 125 liver biopsies of this study by the consultants resulted in a 46% increase in monetary cost. CONCLUSIONS: Practitioners making clinical decisions based on liver biopsy interpretation need to be aware that in a significant number of cases, pathologists are not able to arrive at a correct diagnosis, and thus seeking second opinions on the patients' behalf from experienced pathologists on liver diseases would be prudent. General pathologists should become more familiar with the abnormalities involving interlobular bile ducts and the diagnostic value of certain ancillary histological stains. Clinicians should provide pathologists with sufficient clinical information in terms of laboratory evaluations and clinical findings, so that accurate diagnosis might be facilitated.

Degradation of basement membranes by human matrix metalloproteinase 3 (stromelysin).

Connective tissue cells synthesize and secrete a group of matrix metalloproteinases (MMPs), all of which are capable of degrading the extracellular-matrix components. One of them, MMP-3 (stromelysin) has been shown to degrade purified basement-membrane components, collagen IV and laminin [Okada, Y., Nagase, H. & Harris, E. D., Jr. (1986) J. Biol. Chem. 261, 14245-14255]. Here we report that MMP-3 degrades collagen IV and laminin in intact basement membranes from bovine glomeruli (GBM) and bovine anterior-lens capsules (LBM). Degradation products were analysed by SDS/polyacrylamide-gel electrophoresis to determine the number and sizes of polypeptide fragments. Immunoblotting techniques were used to identify the origins of the fragments, i.e. collagen IV or laminin. The fragments of collagen IV were further mapped using specific antibodies that recognize the N-terminal (7 S) domain, the C-terminal (NC-1) domain, or the major triple-helical region between the terminal domains. Degradation of collagen IV was extensive; many fragments were found, from both GBM and LBM, in the Mr range 25,000-380,000. A large fragment of laminin (Mr greater than 380,000) was found in the GBM digests without reduction, but it dissociated into 220,000-Mr chains upon reduction. The results suggest that MMP-3 plays an important role in the catabolism of basement membranes.

Degradation of basement membranes by Pseudomonas aeruginosa elastase.

Pseudomonas aeruginosa virulence has been attributed in part to extracellular proteinases. We found that one of these proteinases, elastase, extensively degrades intact basement membranes from bovine anterior-lens capsules, bovine glomeruli, and bovine lung, producing about 9, 14, and 9 fragments, respectively, with Mrs in the range of 15,000 to greater than 200,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (nonreducing conditions). Release of hydroxyproline showed that collagen IV was degraded by elastase. Degradation of the newly discovered alpha 3(IV) collagen chain was shown by immunoblotting of digests with Goodpasture's syndrome serum, which contains antibodies that react with an epitope located in the carboxyl-terminal globular (NCl) domain of alpha 3(IV). Comparison of total protein release with collagen IV release showed that noncollagenous protein components were solubilized to the same extent as collagen IV. The extensive degradation of the basement membranes described here suggests a role for elastase in the pathogenic mechanism at the local level when P. aeruginosa infection is present.

Determination of lung as the primary site of cerebral metastatic adenocarcinomas using monoclonal antibody to thyroid transcription factor-1.

Determining the primary site of a cerebral metastatic adenocarcinoma is complicated by the histologic similarity of most adenocarcinomas. Thyroid Transcription Factor-1 (TTF-1) is a highly specific marker of peripheral airway cell neoplasms. Formalin fixed tissue from 30 patients with brain metastasis whose primary sources were clinically and histologically known with certainty were analyzed for immunoreactivity to TTF-1. There were 18 cases of metastatic lung adenocarcinoma. Other metastases were from breast (6), colon (1), prostate (1), kidney (1), paranasal sinus (1), melanoma (1), and intestinal carcinoid (1). No patients with carcinoma of the thyroid were found. Positivity was regarded as intense nuclear reactivity. Twelve (67%) metastatic lung adenocarcinomas stained for TTF-1. None of the cerebral metastases from other body sites showed positivity. In addition, normal brain tissue and astrocytic tumors did not stain for TTF-1. These data show that TTF-1 is a highly specific and reasonably sensitive marker for peripheral airway cell metastasis to the brain.