p53 and mdm-2 expression in malignant melanoma: an immunocytochemical study of expression of p53, mdm-2, and markers of cell proliferation in primary versus metastatic tumors

Alterations in the function of p53, a tumor suppressor gene, have been postulated as a principal underlying mechanism involved in the loss of cell cycle control in human malignancies. Because p53 dysfunction is generally associated with protein overexpression, immunocytochemistry is a valuable technique for the analysis of p53's functional status. We tested the hypothesis that loss of p53 function is a critical event in the early development and progression of human malignant melanoma and can lead to alterations in cell proliferation. We performed an immunocytochemical study in archival fixed, embedded specimens that included 102 melanocytic lesions ranging from benign nevi to metastatic melanoma. In addition to p53, we assessed the p53-associated protein, mdm-2, and markers of cell cycle status (the MIB-1-defined cell proliferation marker; proliferating cell nuclear antigen; and statin, a 57-kDa nuclear protein expressed preferentially by G0 cells). Tumor expression of all nuclear proteins was scored in a semiquantitative fashion related to the fraction of positive tumor nuclei. The overall incidence of significant p53 overexpression was low (8% of primary and 14% of metastatic melanomas). Analysis demonstrated strong correlation between increasing p53 expression in primary versus metastatic lesions (chi 2 analysis, P = 0.001). Correlation was found between increased MIB-1-defined cell proliferation and p53 overexpression in primary melanomas (P = 0.02). Detectable mdm-2 expression was significantly correlated with p53 overexpression (P = 0.02). Comparison of statin and proliferating cell nuclear antigen indices demonstrated inverse correlation (chi 2 , P = 0.03) in the combined groups, but within the metastatic group there was a subset of cases strongly expressing the two markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolism of modified LDL by cultured human placental cells

All major classes of normal circulating lipoproteins can be metabolized by human placental cells. However, the metabolism of abnormal or modified lipoproteins has been little studied. We therefore investigated whether placental cells metabolize acetylated low density lipoprotein (ac-LDL) or oxidatively-modified LDL (ox-LDL), both of which are metabolized by scavenger receptors, and if so, whether modified LDL stimulates progesterone secretion as does normal LDL. Placental macrophages and trophoblasts were isolated on a 40% Percoll gradient after enzymatic digestion. The cellular uptake and degradation of [125I]-ac-LDL was 20-fold higher than [125I]-LDL in both macrophages and trophoblasts. Both cell types demonstrated high affinity and saturable degradation. Similarly, increased esterification of [14C]-labelled oleic acid to cholesterol was observed when cells were incubated with ac-LDL vs. LDL. Uptake of ac-LDL by trophoblasts also was demonstrated by colocalization of fluorescently labelled ac-LDL and fluorescent antibodies specific for trophoblasts. Similar colocalization of fluorescent ac-LDL and fluorescent anti-macrophage specific epitopes was seen in macrophages. Uptake and degradation of [125I]-ac-LDL by placental cells was inhibited by increasing concentrations of unlabelled ac-LDL or fucoidin but not LDL, indicating uptake by a scavenger receptor. Both unlabelled ac-LDL and ox-LDL inhibited uptake of [125I]-labelled ox-LDL, suggesting uptake by a common mechanism. Although secretion of progesterone by trophoblasts was stimulated by incubation with LDL, progesterone secretion by trophoblasts was not stimulated by ac-LDL and only minimally stimulated by ox-LDL.

CONCLUSIONS

Scavenger receptors are present in human placental trophoblasts as well as macrophages. Scavenger receptor activity greatly exceeds that of LDL receptor activity in both cell types. However, cholesterol assimilated via the scavenger receptor pathway appears to be disconnected from endocrine steroidogenesis in trophoblasts. Thus, we hypothesize that scavenger receptors function in trophoblasts to degrade modified lipoproteins and prevent toxic effects on placental cellular function and fetal growth and development.

Heterogeneity of islet pathology in two infants with recent onset diabetes mellitus

The mechanisms by which the beta cells of pancreatic islets are destroyed in insulin-dependent diabetes mellitus (IDDM) are poorly understood. In this report the pancreatic histo- and immunopathology of two children, both HLA-DR 3/4, DQ 2/8 positive and who both died from cerebral oedema within a day of clinical diagnosis of IDDM, were investigated. Patient 1, a 14-month-old girl, had a 4-week history of polydipsia and polyuria. Patient 2, a 3-year-old boy, had 2 days of illness. Both patients had a similarly severe loss of insulin cells but differed markedly as to the extent of lymphocytic islet infiltration (insulitis). Apart from insulitis, marked islet macrophage infiltration was demonstrated in both patients with the HAM-56 monoclonal antibody. Neither patient showed aberrant expression of HLA class II antigens on insulin-immunoreactive cells, but allele-specific HLA-DQ8 expression was evident on endothelial cells. Glutamic acid decarboxylase immunoreactivity was detected in both insulin- and glucagon-immunoreactive cells. It is concluded that the heterogeneity of islet pathology, especially insulitis, may reflect different dynamics and extent rather than different pathomechanisms of immune destruction of islets in IDDM.

Analysis of proliferative grade in glial neoplasms using antibodies to the Ki-67 defined antigen and PCNA in formalin fixed, deparaffinized tissues

In an effort to optimize immunocytochemical methods to evaluate cell kinetics in brain tumors, we studied two newly-developed antibodies which react with formalin resistant epitopes of Proliferating Cellular Nuclear Antigen (PCNA) and Ki-67. These results were compared with standard flow cytometric cell cycle data from the same tumor specimens to determine if these methods correlate with each other, and whether retrospective analysis using these antibodies is feasible for cell kinetic analysis of brain tumors. Thirty-one specimens of glial tumors submitted for flow cytometry during 1992 were also reacted with antibodies to PCNA (PC-10) and Ki-67 (MIB-1). Flow cytometry scores for S-phase Fraction were compared with immunocytochemical scores for both antibodies, using an arbitrary rating of 1 (low, < 4%), 2 (intermediate, 4-6%), 3 (high, > 6%), and 1 (< 25% positive), 2 (26-75% positive), 3 (> 75% positive), respectively. MIB-1 results were found to correlate significantly with the S-phase fraction as determined by flow cytometry. The MIB-1 data showed a trend toward underestimating, i.e., lower scores, the proliferative index compared with flow cytometry. There was less of a correlation between PC-10 antibody scores and flow cytometry S-phase fraction, as PC-10 immunostaining typically overestimated the proliferative rate of brain tumors when compared with flow cytometry. There was an exact correlation between PC-10 and MIB-1 in only 4 cases, whereas in the remaining specimens, PC-10 results were always higher than MIB-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of infectious disease agents in tissue by immunocytochemistry

1. Immunocytochemical procedures have played an increasingly larger role in the identification of infectious disease agents in tissue sections owing to the increased availability and specificity of antibody reagents, the great sensitivity of the methods, and the relative facility with which the studies are performed. 2. Immunocytochemical methods can be applied to routine formalin-fixed tissue for the detection of infectious agents such as viruses, bacteria, fungi, and protozoa among other microorganisms for diagnostic and research purposes.

GM-CSF and M-CSF expression is associated with macrophage proliferation in progressing and regressing rabbit atheromatous lesions

Recent studies have documented that macrophages are a significant cell component of atherosclerotic lesions and may play a significant role in the pathogenesis of these lesions. It has also been documented that markers of cell proliferation (e.g., the proliferating cell nuclear antigen) can be expressed by macrophage subpopulations in atherosclerotic lesions, and there is great interest in identifying cell mediated factors which might be instrumental in macrophage proliferation in this context, perhaps accounting for the persistence of macrophages within this context. Important candidates for this function include granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF); the latter has been previously demonstrated to be expressed in human and rabbit atherosclerotic lesions. We have extended these studies by studying immunocytochemical localization of GM-CSF and M-CSF in progressing and regressing lesions of cholesterol-fed rabbits, documenting expression of these factors predominantly in macrophages, but also in some smooth muscle-cells and endothelial cells. The simultaneous documentation of macrophage subpopulations expressing the proliferating cell nuclear antigen in the same lesions provides evidence to support the hypothesis that macrophage GM-CSF and M-CSF production represents a factor underlying macrophage proliferation and accumulation in atherosclerotic lesions.

Characterization of the early lesion of 'degenerative' valvular aortic stenosis. Histological and immunohistochemical studies

BACKGROUND

Nonrheumatic stenosis of trileaflet aortic valves, often termed senile or calcific valvular aortic stenosis, is considered a "degenerative" process, but little is known about the cellular or molecular factors that mediate its development.

METHODS AND RESULTS

To characterize the developing aortic valvular lesion, we performed histological and immunohistochemical studies on Formalin-fixed and methanol-Carnoy's-fixed paraffin-embedded aortic valve leaflets or on frozen sections obtained at autopsy from 27 adults (age, 46 to 82 years) with normal leaflets (n = 6), mild macroscopic leaflet thickening (n = 15), or clinical aortic stenosis (n = 6). Focal areas of thickening ("early lesions") were characterized by (1) subendothelial thickening on the aortic side of the leaflet, between the basement membrane (PAS-positive) and elastic lamina (Verhoeff-van Gieson), (2) the presence of large amounts of intracellular and extracellular neutral lipids (oil red O) and fine, stippled mineralization (von Kossa), and (3) disruption of the basement membrane overlying the lesion. Regions of the fibrosa adjacent to these lesions were characterized by thickening and by protein, lipid, and calcium accumulation. Control valves showed none of these abnormalities. Immunohistochemical studies were performed using monoclonal antibodies directed against macrophages (anti-CD68 or HAM-56), and contractile proteins of smooth muscle cells or myofibroblasts (anti-alpha-actin and HHF-35) or rabbit polyclonal antiserum against T lymphocytes (anti-CD3). In normal valves, scattered macrophages were present in the fibrosa and ventricularis, and occasional muscle actin-positive cells were detected in the proximal portion of the ventricularis near the leaflet base, but no T lymphocytes were found. In contrast, early lesions were characterized by the presence of an inflammatory infiltrate composed of non-foam cell and foam cell macrophages, occasional T cells, and rare alpha-actin-positive cells. In stenotic aortic valves, a similar but more advanced lesion was seen.

CONCLUSIONS

The early lesion of "degenerative" aortic stenosis is an active inflammatory process with some similarities (lipid deposition, macrophage and T-cell infiltration, and basement membrane disruption) and some dissimilarities (presence of prominent mineralization and small numbers of smooth muscle cells) to atherosclerosis.

Expression of c-erb B-2 oncogene product in persistent gestational trophoblastic disease

OBJECTIVE

Much debate exists on the initiation of chemotherapy for women at risk for persistent gestational trophoblastic disease. This is a result of a lack of early predictors for the development of persistent gestational trophoblastic disease after evacuation of a complete hydatidiform mole, because the only current reliable method of detection and diagnosis lies in persistent or rising postmolar beta-human chorionic gonadotropin values. We used immunocytochemical techniques to retrospectively study the expression of the c-erb B-2 oncogene product in formalin-fixed, paraffin-embedded trophoblastic tissues as a potential indicator of the development of persistent gestational trophoblastic disease.

STUDY DESIGN

In this retrospective study 56 trophoblastic tumors were examined by means of immunocytochemical techniques to stain for the oncogene product for evidence of c-erb B-2 expression. Our 56 cases included original tissue from 20 cases of complete mole that progressed to persistent gestational trophoblastic disease, seven cases of choriocarcinoma after term pregnancy or abortion, and 29 cases of hydatidiform mole representing postevacuation, spontaneously regressing disease (including one partial mole). We also studied 11 cases of first-trimester trophoblast and 15 cases of term placenta as additional controls.

RESULTS

Our results showed positive immunostaining for c-erb B-2 gene product in one case of persistent gestational trophoblastic disease, with negative staining in all other cases in the study groups and controls.

CONCLUSION

Analysis for the significance of c-erb B-2 expression in persistent gestational trophoblastic disease showed that this correlation between c-erb B-2 expression and persistent gestational trophoblastic disease is not significant, suggesting that future efforts should be directed at the involvement of different oncoproteins.

Accumulation of macrophages in the arterial vessel wall following experimental balloon angioplasty

Smooth muscle cell (SMC) proliferation is a key event in the development of restenosis after balloon angioplasty, and it is thought that macrophages play an important role in the complex process of activation of SMCs after vascular injury induced by balloon angioplasty. The study was designed to determine the time course of the accumulation of macrophages in the intimal layer following experimental balloon angioplasty. To determine the extent and time course of the accumulation of macrophages after experimental balloon angioplasty, an intimal atheroma was produced by repeated weak electrical stimulation of the right carotid artery of 45 male New Zealand White rabbits. Additionally, the animals received an 0.5% cholesterol diet during the 28 days of plaque development. Transluminal balloon angioplasty was subsequently performed. At 3, 7, 14, 21, 28 and 42 days after balloon treatment the vessels from at least five animals from each group were excised and analysed for the presence of macrophages using immunocytochemical techniques. In one group of five animals plaque development occurred without subsequent balloon angioplasty; the animals were killed after 21 days (sham group). SMCs were identified by immunohistological staining of alpha-actin. Intimal thickening increased after dilatation from 137 +/- 62 microns (control group without balloon treatment) to 244 +/- 47 microns in the 42 days after angioplasty (P < 0.05). The percentage of macrophages in the intimal layer displayed a significant increase (P < 0.01) at 14 days after angioplasty (9.1 +/- 4.3% vs 2.0 +/- 1.7% in the control group).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell proliferation after balloon injury of iliac arteries in the cholesterol-fed New Zealand White rabbit

Acute mechanical injury of an artery results in neointimal hyperplasia that is due at least in part to cell proliferation within the vessel wall. The purpose of this study was to quantify cell proliferation activity in the iliac artery of New Zealand White rabbits after balloon injury and cholesterol feeding. Retrograde pullback balloon injury of iliac arteries was performed, and the animals were then fed a 2% cholesterol diet. At intervals from day 1 through day 35 postinjury, iliac arteries were obtained for histological analysis. Intimal and medial areas were measured morphometrically. Total number of cells within the intima and media was counted. Smooth muscle cell-predominant or macrophage-predominant regions of the intima and media were identified using HHF-35 and RAM-11 immunocytochemical markers, respectively. Number of cells in the proliferative phase of the cell cycle was measured by using the proliferating cell nuclear antigen and bromodeoxyuridine techniques. Thirty-one arteries from 16 rabbits were available for analysis. Total number of cells and number of cells per square millimeter within the media did not change significantly from day 1 through day 35 postinjury. Total number of cells within the intima increased significantly, but the number of cells per square millimeter of intima decreased significantly during the same time period. Proliferative activity was identified in the media between days 3 and 35 with peak activity at day 3 postinjury. Proliferative activity in the intima was present in all specimens from day 8 through day 35. Proliferative activity was present in both HHF-35- and RAM-11-predominant regions of the intima.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell proliferation in human soft tissue tumors correlates with platelet-derived growth factor B chain expression: an immunohistochemical and in situ hybridization study

The authors tested the hypothesis that the B chain of the platelet-derived growth factor (PDGF), a known connective tissue mitogen and growth factor, could be expressed by human soft tissue tumors, and that its expression could play a role in the control of cell proliferation in these tumors. Using a set of 56 soft tissue tumors, including benign tumors and all three grades of sarcomas, PDGF-B chain protein was localized using immunohistochemistry and PDGF-B mRNA was localized using in situ hybridization. The hypothesis that PDGF-B expression was related to cell proliferation was tested by simultaneously demonstrating the expression of the proliferating cell nuclear antigen in sequential tissue sections of the same tumors. Sixty and 82% of tumors had demonstrable PDGF-B mRNA and protein, respectively, with a strong correlation between their degrees of expression (P = 0.0001). Among the sarcomas, a strong correlation between PDGF-B expression and increasing malignant tumor grade (P = 0.006), and between PDGF-B expression and increasing proliferating cell nuclear antigen index (P = 0.01) was found. All tumors were also demonstrated to express the beta receptor of PDGF via immunohistochemistry. These studies suggest that PDGF-B expression may be an important mediator of cell proliferation control, via an autocrine mechanism, in human soft tissue tumors and may correlate with clinical outcome in the sarcomas.

Human papillomavirus-immortalized keratinocytes are resistant to the effects of retinoic acid on terminal differentiation

In order to study how human papillomaviruses (HPVs) can alter normal epithelial cell differentiation, we looked at the response to retinoic acid (RA) of HPV-immortalized keratinocytes grown on organotypic cultures. Ten- to 30-fold higher concentrations of RA were required to block terminal differentiation in these cultures when compared to organotypic cultures of control cells. This resistance to RA was associated with maintained expression of differentiation-specific markers and, for keratin K1, Northern analysis showed that K1 mRNA was also detectable at 30-fold higher concentrations of RA in HPV organotypic cultures when compared to controls. These differences were reproducible and characteristic of all HPV cell lines studied, including very early passage HPV16-containing cell lines, suggesting that expression of HPV genes leads to this phenotype. Expression of epithelia-specific components of the RA response pathway was also studied by Northern analysis. At all RA concentrations, there were no detectable differences in overall levels of retinoic acid receptor gamma or cytosolic RA-binding protein II mRNA found. Retinoid X receptor alpha expression was also evaluated, and, in two of three HPV-immortalized cell lines, it was found to be 2 to 3 times as abundant as in controls. Although this difference in retinoid X receptor alpha expression could contribute to RA resistance, the mechanism involved in producing this resistance could not be fully elucidated in these studies. However, resistance to the effects of RA on epithelial differentiation is demonstrated in organotypic cultures of HPV-containing cells, and it is shown that this is associated with maintenance of RNA and protein expression of differentiation-associated genes at abnormally high concentrations of RA.

Detection of Chlamydia pneumoniae in aortic lesions of atherosclerosis by immunocytochemical stain

Recent evidence has shown the presence of Chlamydia pneumoniae antigens and nucleic acid in coronary artery atheromas from autopsy patients in South Africa. In this study, the immunocytochemical technique was used to demonstrate C pneumoniae antigens in atheromas of the aorta in autopsy patients from retrospective aortic atherosclerosis studies at the University of Washington. The patients were 34 to 58 years old. Immunoperoxidase staining using Chlamydia-specific monoclonal antibodies showed one of four fatty streaks and six of 17 fibrous plaques were positive for C pneumoniae antigens; four control aortic tissues were negative. Two of the positive plaques were from the same patient. Double-label immunocytochemical staining using Chlamydia- and tissue type-specific monoclonal antibodies demonstrated the antigens in the cytoplasm of macrophages and smooth muscle cells in the atheromatous lesion. This study suggested a wider involvement of C pneumoniae organisms in atherosclerotic lesions of the arterial system than has previously been documented.

Detection of cell proliferation in tissue sections

1. Cell proliferation is of interest since abnormal cell proliferation appears to be a precursor of tumorigenesis and also because the quantitative description of cell proliferation in tumors can be used to predict the biological behavior of a particular neoplasia. 2. There are several reliable methods of studying cell proliferation in tissues. One of the most important is the detection of the Ki67 defined antigen in frozen sections. The number of cells expressing Ki67 correlates with histological grades of tumors and can also be predictive of clinical outcome. The Ki67 can be localized in tissue sections using monoclonal antibodies in association with the immunoperoxidase technique. 3. Proliferating cell nuclear antigen (PCNA) is a component of DNA polymerase-delta and is another important cell proliferation marker manifesting a striking increase in concentration during the S phase of the cell cycle. 19A2 and PC10 are two different monoclonal antibodies which can be employed to detect PCNA in paraffin-embedded tissues. 4. Molecular biology has also been making a great contribution to the study of cell proliferation. The most recent innovation in tissue identification of proliferating cells is the use of in situ hybridization for the localization of histone H3 and/or H4 mRNA. H3 mRNA-positive cells appear to be present in basal cells of the skin and in crypt cells of the intestine which are sites with high proliferation rate.

Human atherosclerosis. IV. Immunocytochemical analysis of cell activation and proliferation in lesions of young adults

The accumulation of smooth muscle cells is a major phenomenon associated with the pathogenesis of lesions of atherosclerosis. Smooth muscle cell proliferation in response to the release of growth factors from neighboring cells, both smooth muscle and macrophages, is one mechanism postulated to account for the increasing numbers of smooth muscle cells as atherosclerotic lesions progress. Indeed, we recently demonstrated the B chain of platelet-derived growth factor (PDGF-B), a potent smooth muscle mitogen, within macrophages in monkey and human lesions of atherosclerosis. To further test the hypothesis that smooth muscle proliferation and/or activation (eg, expression of major histocompatibility complex proteins) plays a role in the early development of these lesions, we applied antibodies to PDGF-B, HLA-DR (a marker of cell activation), and proliferating-associated marker) on a series of early human atherosclerotic lesions from young adults in conjunction with cell-type-specific antibodies. Smooth muscle cells had previously been demonstrated to comprise a major fraction of the cell population in these lesions. In a continuing study of early and intermediate lesions of individuals ranging in age from 15 to 34 years, PDGF-B was detected within macrophages in 2 of 15 lesions. There was no evidence of HLA-DR expression by the smooth muscle cell population in any of the lesions. PCNA-positive cells comprised less than 2% of the cells in the lesions, and the majority of these were blood-borne cells (macrophages and/or lymphocytes), although a small fraction of the PCNA-positive cells were identified as smooth muscle. Concurrent PCNA and 5'-bromodeoxyuridine studies of peripheral blood monocytes demonstrated the presence of significant numbers of cells positive for these proliferation-related markers. It is concluded that the growth factor PDGF-B may have a role in regulating cell proliferation in early human fatty streaks, but the number of proliferating smooth muscle cells is relatively small, and there is no evidence of smooth muscle cell activation, as judged by HLA-DR positivity, in these lesions.

Expression of the HPV16 E7 gene generates proliferation in stratified squamous cell cultures which is independent of endogenous p53 levels

Monolayer cultures of human foreskin and ectocervical epithelial cells were infected with retroviral vectors expressing HPV16 oncogenes, selected for G418 resistance, and cultured organotypically so that they reformed the fully differentiated, stratified squamous tissues from which they were originally derived. Expression of HPV16 E7 prevented cell cycle withdrawal in the suprabasal layers of these stratified cultures but had no effect on terminal differentiation. Cultures expressing E7 alone and those coexpressing E6 and E7 were identical in terms of suprabasal proliferation and terminal differentiation, but they differed in expression of the endogenous tumor suppressor protein p53. Immunohistochemically detectable p53 protein localized to the proliferative compartment in normal and E7-containing cultures but was undetectable in those cultures which coexpressed E6 and E7. This result suggests that E7-induced suprabasal proliferation is independent of the steady-state level of p53.

Overexpression of p53 in head and neck cancer

The putative tumor suppressor gene p53 plays a key role in the regulation of cell proliferation. Functional loss of p53 protein through mutation or viral oncogene-complexing can result in p53 protein overexpression detectable by immunocytochemistry, which in turn has been associated with markers of poor prognosis in some cancers. We report here an analysis of p53 overexpression in fixed, embedded specimens from 81 prospectively collected head and neck tumors, both benign and malignant, including 55 squamous cell carcinomas, using monoclonal pAb1801. Sixty-two percent of the squamous cell carcinomas from the head and neck region overexpressed p53, whereas none of the benign tumors or adjacent normal tissues overexpressed p53. Overexpression of p53 was strongly associated (p < 0.01, two-tailed chi-square) with a histologic malignancy grading scale previously shown to have prognostic capabilities. We conclude that p53 overexpression is one of the most common abnormalities identified in head and neck cancer, and may be a useful marker in the study of multistep progression of tumorigenesis.

Time course and cellular characteristics of the iliac artery response to acute balloon injury. An angiographic, morphometric, and immunocytochemical analysis in the cholesterol-fed New Zealand white rabbit

Evaluation of the response of the arterial vessel wall to acute arterial injury in experimental models has taken on substantial importance because of an increasing interest in angioplasty treatment of human atherosclerotic lesions. In this study, the response of normal arterial vessels to acute balloon injury was studied in 45 iliac artery segments from 24 New Zealand White rabbits fed a 2% cholesterol diet. At specified time points between 1 and 41 days after the initial balloon pullback injury, the iliac arteries were analyzed by angiographic, morphometric, and immunocytochemical techniques. Angiographic measurements indicated progressive compromise of the iliac artery lumen with increasing duration of time from injury. Morphometric measurements showed that intimal area increased from 0.004 +/- 0.01 mm2 3 days after injury to 1.15 +/- 0.30 mm2 34-41 days after injury. Cell line-specific immunocytochemical analysis identified the macrophage as a prominent component of the earliest intimal cellular infiltrate. Smooth muscle cells appeared within the intima 7-9 days after injury. As the intima increased in area, macrophages predominated along the internal elastic lamina aspect of the intimal lesion while smooth muscle cells occupied the portion of the intima adjacent to the lumen. In summary, retrograde balloon pullback injury followed by cholesterol feeding results in progressive arterial luminal narrowing due to a progressively enlarging intimal cellular infiltrate. The temporal and spatial contributions of smooth muscle cell and macrophage components of the developing intimal cellular infiltrate have been characterized.

Markers for dysplasia of the upper aerodigestive tract. Suprabasal expression of PCNA, p53, and CK19 in alcohol-fixed, embedded tissue

Recognition of premalignant lesions in the oral epithelium has the potential to increase survival rates for squamous cell carcinoma of the oral cavity. It has previously been reported that cytokeratin 19 (CK19), a 40-kd epithelial cytoskeletal protein within the suprabasal squamous epithelium, is a specific marker of moderate-to-severe dysplasia and carcinoma in situ in oral cavity squamous epithelium. In contrast, normal epithelium and hyperplastic lesions reportedly express CK19 only in the basal layer if at all. The authors chose to test and extend this hypothesis by studying suprabasal CK19 expression and dysplasia of the oral cavity and upper aerodigestive tract in paraffin-embedded specimens that had been fixed in alcohol, a superior fixative for the preservation of cytokeratins. The authors examined 56 alcohol-fixed, paraffin-embedded specimens including 37 from the oral cavity, using two antibodies specific for CK19 (Ks19.1 and 4.62), an antibody to the nuclear proliferation marker, proliferating cell nuclear antigen (PCNA) (19A2), and an antibody to the putative tumor suppressor gene, p53 (pAb1801). The lesions were classified as normal, hyperplasia, mild dysplasia, moderate dysplasia, severe dysplasia/carcinoma in situ, or invasive squamous cell carcinoma, following standard histologic criteria. Immunocytochemically stained sections were scored for the presence or absence of suprabasal CK19, suprabasal PCNA, and p53 positivity, regardless of location. The immunostaining patterns of the two anti-CK19 antibodies were essentially equivalent. Except for one laryngeal specimen, normal epithelium, when positive, showed CK19 expression only in scattered cells throughout the basal layer. Proliferating cell nuclear antigen-positive nuclei were found exclusively in the basal layer. In areas of hyperplasia, CK19 immunostaining was absent or confined to the basal layer in 20 of 38 specimens and was expressed in suprabasal cells in 18 of 38 hyperplastic specimens. Proliferating cell nuclear antigen immunostaining in all cases of hyperplasia was limited to the basal layer. Severe dysplasia and carcinoma in situ showed suprabasal CK19 staining in six of nine specimens and no CK19 staining in three of nine specimens. In contrast, suprabasal PCNA immunostaining was found in all dysplasia and carcinoma in situ cases. p53 expression was detected in three of nine severe dysplasia/CIS specimens and was immunocytochemically undetectable in all normal, hyperplasia, and mild to moderate dysplasia specimens. The authors conclude that suprabasal CK19 expression is neither a sensitive nor a specific marker of premalignancy in oral epithelium and cannot be used to distinguish hyperplasia from dysplasia. In contrast, a strong correlation between suprabasal expression of PCNA, a marker for proliferating cells, and dysplasia/carcinoma in situ was evident.(ABSTRACT TRUNCATED AT 400 WORDS)

Paget's disease and melanoma of the vulva. Use of a panel of monoclonal antibodies to identify cell type and to microscopically define adequacy of surgical margins

The ability of a panel of monoclonal antibodies generated in this laboratory to identify "pagetoid" melanoma cells and distinguish them from true Paget's adenocarcinoma cells in a retrospective analysis of vulvar neoplasms was investigated. Paraffin blocks of formalin and Carnoy's fixed tissue from 15 cases of vulvar Paget's disease and 11 cases of primary vulvar melanoma were retrieved and sections were incubated with the following panel of monoclonal antibodies: HMB45, a melanoma-specific monoclonal antibody; and 35 beta H11 and 34 beta E12, two different anti-cytokeratin monoclonal antibodies, to low molecular and high molecular weight cytokeratins, respectively. The anti-melanoma monoclonal antibody (HMB45) positively identified the melanoma cells, distinguishing them from normal melanocytes, in all 11 cases of melanoma. In contrast, the HMB45 antibody failed to react with the intraepithelial neoplastic cells in all cases of Paget's disease. These latter malignant cells were strongly positive only with the monoclonal anti-low molecular weight cytokeratin antibody 35 beta H11. This latter antibody absolutely distinguished tumor cells from neighboring uninvolved squamous epithelium, which was positive only with the monoclonal antibody 34 beta E12. Using this panel of monoclonal antibodies, the surgical margins could also be better evaluated; in at least one case the surgical margin thought by histological evaluation to be free of tumor was demonstrated by immunocytochemistry to be positive for tumor. In the vulvectomy specimens obtained in both diseases, Paget's or melanoma cells were identified in sections histologically interpreted as free of tumor. Thus, a panel of monoclonal antibodies is able to identify, with high sensitivity and specificity, vulvar melanoma cells and absolutely distinguish them from vulvar Paget's cells and can help in evaluating surgical margins in a more accurate manner.

Production of a monoclonal antibody to an attachment protein derived from human cementum

Cementum is the mineralized structure that covers the surface of the roots of teeth; it serves as the attachment site for collagen fibers of adjacent soft connective tissues. Very little is known about how cementum formation is regulated or how it affects other periodontal structures. We have raised a monoclonal antibody that may aid in studies to determine the biology and function of cementum. Mice were immunized with a 55-kDa attachment protein partially purified from human cementum and a monoclonal antibody, H166, was produced. Incubation of tissue sections with this antibody and fluorescein isothiocyanate-conjugated secondary antibody revealed that it immunostains cementum but not dentin, gingiva, or periodontal ligament. Alveolar bone did not bind the antibody, although a few paravascular cells were positive. Long bones, kidney, liver, skin, and several other tissues were negative. Protein fractions separated from cementum extracts by binding to immobilized H166 column contained 55-, 49-, 39-, 29- to 31-, and 23- to 26-kDa components that cross-reacted with the antibody in Western blots; these components were previously shown to be derived from a common precursor. We conclude that the antibody recognizes a group of proteins related to 55-kDa attachment protein in cementum. Our data show that the antibody could serve as a marker for cementum.