Biomedical subjects

O W Kamel

Publications and source records attributed to O W Kamel.

49 records · Page 3Linked to original sources

PubMed1992

Malignant histiocytic neoplasms of the small intestine.

Immunologic studies have demonstrated that the vast majority of hematolymphoid neoplasms previously designated as "histiocytic" are lymphoid in origin. Consequently, malignancies of macrophage lineage are considered rare by most authors; indeed, their existence is doubted by some. Herein we report two cases of malignant histiocytic neoplasms (malignancies of macrophage lineage) of the small intestine. Both patients presented in the 7th decade with symptoms related to an abdominal mass. The polypoid tumors protruded into the intestinal lumen, extended through the entire thickness of the bowel wall, and involved regional lymph nodes. Microscopically, sheets of large pleomorphic histiocytic cells infiltrated around crypts and were associated with an admixture of bizarre giant cells and inflammatory cells. Mitotic figures were easily found. Ultrastructurally, the cells lacked desmosomes and had indented or kidney-shaped nuclei and cytoplasm containing mostly lysosomes and dense lipid droplets. In both cases, paraffin section immunohistochemistry revealed reactivity of tumor cells for CD45RB (LCA), CD45RO (A6), CD68 (KP1), CD15 (LeuM1), and lysozyme. Frozen section immunohistochemistry performed in one case further supported the macrophage phenotype. Southern blot studies of this case did not reveal immunoglobulin or T-cell receptor beta chain gene rearrangements. One patient initially treated by surgery only died of disease 3 years after diagnosis. The second patient is alive and disease-free 2 years following postoperative combination chemotherapy. The diagnosis of malignant histiocytic neoplasms requires the use of a panel of immunohistochemical markers and may be supported by electron-microscopic studies.

Antigens, CD↗

PubMed1992

Estimation of tumor growth fractions in archival formalin-fixed, paraffin-embedded tissues using two anti-PCNA/Cyclin monoclonal antibodies. Factors affecting reactivity.

Immunohistochemical detection of cell cycle-related markers for estimation of tumor growth fractions using paraffin-embedded tissue sections would have applications in experimental and clinical pathology as an in situ histologic alternative to flow cytometry. The monoclonal antibodies 19A2 and PC10 detect the proliferating cell nuclear antigen (PCNA/Cyclin), an auxiliary protein to DNA polymerase-delta. In a prospective group of uniformly handled, formalin-fixed malignant lymphomas we previously demonstrated 19A2 to be a reliable marker of proliferative activity similar to Ki-67 in frozen tissue. The present study examines the applicability of this technique in archival formalin-fixed material. Studies on tonsilar tissue revealed that formalin fixation beyond 30 hours adversely affected reactivity of 19A2, possibly explaining the variable results in nonuniformly fixed archival material. We found that only 27 (56%) of 48 archival cases of infiltrating ductal carcinoma showed sufficient reactivity with 19A2 to permit reliable quantification of the tumor growth fraction. Acid pretreatment with 2N HCl had no apparent effect on 19A2 reactivity. Using both antibodies on a group of 32 archival lymphomas, carcinomas, and sarcomas, significantly more biopsies stained reliably for PC10 (84%) than for 19A2 (72%; P < 0.036). Further, none of the cases that did not react with PC10 reacted with 19A2. PC10 may recognize a different epitope of PCNA/Cyclin which may be more resistant to alterations by fixation. In the 23 cases that reliably stained for both markers, largely carcinomas, there was excellent correlation between estimated growth fractions (r = 0.96). Although immunostaining provides a useful way to estimate tumor growth fractions in paraffin-embedded tissues, modifications of technique and cautious interpretation of results are advisable when using archival material.

Antibodies, Monoclonal↗

PubMed1992

Localization of proliferating cell nuclear antigen (PCNA/Cyclin) in workshop cases of Hodgkin's disease and non-Hodgkin's lymphoma.

Proliferating cell nuclear antigen (PCNA/Cyclin) is a 36-kD protein that is present in cycling cells but not in resting cells, and therefore represents a marker of tumor proliferation. Application of anti-PCNA/Cyclin monoclonal antibodies has shown that this protein is localized to the nucleus of cycling cells, with the exception of cells in mitosis, which demonstrate faint cytoplasmic reactivity. Recently, Benjamin and Gown found that Reed-Sternberg cells and variants show nuclear and cytoplasmic staining with anti-PCNA/Cyclin antibody 19A2, and suggested that this feature may be useful in distinguishing Hodgkin's disease from other tumors. This report describes the reactivity of 42 workshop cases that were stained with anti-PCNA/Cyclin antibodies 19A2 and/or PC10. Thirty-three (79%) of the 42 cases showed adequate reactivity to allow for interpretation of staining localization. In the group of reactive cases, 26 (79%) showed nuclear and cytoplasmic staining. The localization of PCNA/Cyclin was compared with the consensus diagnosis in each case. Eighty percent of cases classified as Hodgkin's disease, 67% of cases classified as non-Hodgkin's lymphoma, and 100% of unresolved cases showed both nuclear and cytoplasmic staining. The incidence of cytoplasmic PCNA/Cyclin was not different between Hodgkin's disease and non-Hodgkin's lymphoma in this study.

Hodgkin Disease↗

PubMed1992

Follicular lymphomas of the gastrointestinal tract. Pathologic features in 31 cases and bcl-2 oncogenic protein expression.

The gastrointestinal tract is the most common site for extranodal lymphomas, but follicular lymphomas involving the gut are rare. To study their pathologic features and bcl-2 expression, 31 follicular lymphomas of the GI tract were reviewed and unstained paraffin sections from 24 of the cases were immunohistochemically stained using a monoclonal antibody for the peptide product of the proto-oncogene bcl-2. The most common site of lymphoma involvement was the small intestine, especially the terminal ileum. Gastric lymphomas tended to present clinically with symptomatic ulcers and small intestinal lesions presented with obstruction. Five cases involving the terminal ileum or colon had a gross appearance of multitudinous mucosal polyps and were considered to represent examples of "multiple lymphomatous polyposis." Enhanced expression of the bcl-2 oncogenic protein was detectable in lymphoma cells in 75% of cases and at lower levels in normal lymphoid cells in most cases. Small cleaved or mixed cell lymphomas were more likely to show enhanced expression than were large cell cases. Reactive germinal centers showed no bcl-2 staining. It is concluded that follicular GI lymphomas are associated with distinctive pathological features. In their tendency to express bcl-2, these neoplasms resemble their lymph node-based counterparts. Immunohistochemical staining for enhanced bcl-2 expression is of potential diagnostic utility in distinguishing between follicular lymphoma and follicular lymphoid hyperplasia in the gastrointestinal tract. The relevance of the results to lymphoma of mucosa-associated lymphoid tissue (MALT) is discussed.

Female↗

PubMed1992

In situ proliferative epithelial lesions of the breast.

Considerable progress has been made over the last several years toward understanding the significance of noninvasive epithelial changes in the breast. This progress, in essence, is the result of categorizing in situ alterations according to their clinical significance, or more specifically, according to the risk that such lesions carry to the patient for development of a subsequent invasive carcinoma. This article summarizes the histopathological criteria that are currently used to define morphologic categories and, perhaps more importantly, it reviews the clinical implications of the diagnoses that result from this categorization.

Breast Neoplasms↗

PubMed1992

Breast biopsies: the content of the surgical pathology report.

In the context of recent developments, the role of the surgical pathologist in evaluating and reporting breast cancer specimens has become more important. The pathologist must not only diagnose carcinoma in a given patient, but must also document a set of morphologic features that have been shown to be important in determining prognosis and guiding therapy.

Biopsy↗

PubMed1991

Growth of primary T-cell non-Hodgkin's lymphomata in SCID-hu mice: requirement for a human lymphoid microenvironment.

We reasoned that the SCID-hu mouse could provide an appropriate lymphoid or stromal microenvironment to support the growth of primary human lymphoma. Heterotransplantation of nine cases of primary T-cell non-Hodgkin's lymphoma (NHL) into untreated SCID mice and SCID mice reconstituted with human fetal thymus, spleen, and liver (SCID-hu) resulted in the development of lymphoid tumors in five (56%) cases. Two clonal T-cell NHL grew after a mean of 90 days after injection of primary lymphoma cell suspensions into the thymus xenografts in SCID-hu mice and failed to grow in a variety of sites in SCID mice, except for small tumors that developed after a long (157-day) latency period after intracranial injection of tumor cell suspensions into weanling SCID mice. Successful serial transplantation of NHL in SCID and SCID-hu mice required the presence of a human lymphoid or tumor microenvironment, and was enhanced by pretreating the SCID mice with 175 rad radiation and antiasialo antisera. Analysis of the primary and transplanted T-cell tumors showed identical patterns of T-cell surface markers by flow cytometry and immunophenotyping of fixed tissue sections, and, in one case, reactivity with a specific monoclonal antibody to V beta 5.1. Genotyping of the transplanted tumors showed T-cell receptor gene rearrangements identical to those present in the primary tumors. In one case, the presence of Epstein-Barr virus-positive B cells in association with the primary tumor resulted in the growth of a lymphoblastoid B-cell neoplasm in addition to the malignant T-cell lymphoma after transplantation of tumor fragments to SCID mice. The data support the hypothesis that a human lymphoid microenvironment enhances the growth of T-cell NHL in SCID mice. The SCID-hu thymus graft provides an apparently unique microenvironment that supports the growth of primary T-cell NHL, and can be used to study the interaction between lymphoma cells, nontransformed lymphoid cells, and the surrounding stromal microenvironment in vivo.

Animals↗

PubMed1991

Pigmented purpuric eruptions: immunopathologic studies supportive of a common immunophenotype.

Traditionally, the pigmented purpuric eruptions (PPE) have been subdivided into four histologic categories, based upon variations in histologic pattern and clinical morphologies. In recent years, it has become apparent that the lesions behave similarly, and this family of eruptions has become grouped under the term PPE. The pathogenesis of these eruptions is largely unknown. In this study, we examined 13 examples of the histologic and clinical subtypes of the PPE with a panel of hematolymphoid immunophenotypic markers, in hopes of better understanding the pathogenesis of these curious eruptions. All lesions examined showed a predominantly T cell infiltrate composed of a mixture of OPD4 (CD4) positive and OPD4 negative cells. B cells were rare. Macrophages did not comprise a significant component of the infiltrate. The staining pattern was relatively constant, independent of the histologic pattern (i.e., Schamberg's vs. Gougerot-Blum, etc) of the PPE. Our results suggest that PPE are a group of related eruptions which may have a common pathogenesis. It seems likely that the vascular damage and erythrocyte extravasation are secondary to a localized cell-mediated immunologic event.

Adolescent↗

PubMed1991

Growth fraction estimation of malignant lymphomas in formalin-fixed paraffin-embedded tissue using anti-PCNA/Cyclin 19A2. Correlation with Ki-67 labeling.

The immunohistochemical detection of PCNA/Cyclin, a nuclear protein associated with cell proliferation, represents a potentially useful tool for the study of tumor proliferative activity. Previous studies investigating the reactivity of anti-PCNA/Cyclin monoclonal antibody 19A2 have not clearly defined the population of proliferating cells with which 19A2 reacts in tissue sections. The authors describe a method for detection of PCNA/Cyclin in formalin-fixed, paraffin-embedded tissue using a routine biotin-streptavidin immunohistochemical system that employs an anti-IgM, mu-chain-specific second-stage antibody. The authors used this method to study the proliferative activity of 24 malignant lymphomas, consisting of 12 low-grade lymphomas (LGLs) and 12 intermediate-grade lymphomas (IGLs), and five reactive tonsils. 19A2 data was compared with Ki-67 labeling in frozen sections in the same group of cases. 19A2 provided easily detectable nuclear staining of proliferating cells with reactive cells demonstrating varying intensity of staining, this latter finding most likely due to the varying nuclear concentration of PCNA/Cyclin protein during the cell cycle. In tonsils, 19A2 reacted with germinal center cells and basal keratinocytes. In the malignant lymphomas, there was good correlation between 19A2 and Ki-67 data (r = 0.90, P less than 0.001). The subgroup of LGLs showed a mean PCNA/Cyclin of 26% and a mean Ki-67 of 28%. In the subgroup of IGLs, mean PCNA/Cyclin = 54% and mean Ki-67 = 59%. These results indicate that 19A2 detects a fraction of proliferating cells that is similar to that detected by Ki-67, ie, the growth fraction, and that 19A2 is a reliable marker of proliferative activity in uniformly handled, formalin-fixed, paraffin-embedded tissue.

Antibodies↗

PubMed1991

Heterogeneity of epithelial marker expression in routinely processed, poorly differentiated carcinomas.

The application of immunohistochemical markers against epithelial antigens has proved useful for studying tumor differentiation and in aiding tumor diagnosis. However, the reactivity of various epithelial markers with poorly differentiated carcinomas (the situation in which they are most often used) has not been well established. As a result, it is unclear how negative results should be interpreted and how often more than one antibody may be needed to document the epithelial nature of poorly differentiated neoplasms. We studied 98 poorly differentiated epithelial tumors with AE1, CAM 5.2, and EMA to assess the use of these markers in their diagnosis. Both CAM 5.2 and EMA provided support for epithelial differentiation in 71% (70/98) of the cases, while AE1 stained 50% (49/98) of the tumors; CAM 5.2 was the single most useful marker in the subset of poorly differentiated neuroendocrine carcinomas, staining 20 (77%) of 26 tumors. Use of these markers in pairs increased the recognition of epithelial differentiation (at least one marker showing positive staining) as follows: AE1/CAM 5.2, 80% (78/98); AE1/EMA, 87% (85/98); and CAM 5.2/EMA, 99% (97/98). Thirty carcinomas stained with all three markers, 34 with two markers, and in 34 cases only one antibody supported epithelial differentiation. Twelve (21%) of 58 tumors showed evidence of S100 reactivity. None of the 71 cases to which PD7 was applied showed staining This study indicates that poorly differentiated carcinomas are heterogeneous in their expression of antigens recognized by AE1, CAM 5.2, and EMA. Moreover, these results quantitate the probability of reactivity with poorly differentiated carcinomas for each marker and support the use of one or more antibodies in a "backup" panel when a negative result is obtained with a single antibody and the diagnosis of carcinoma is still suspected.

Antibodies, Monoclonal↗

PubMed1990

Large radiolucent area of the anterior mandible.

A case and review of the pathogenesis of a large radicular cyst has been presented. The radicular cyst is a common finding in dental practice, but is usually confined to the apical area of one to two teeth. Large destructive lesions are uncommon. A thorough clinical and radiographic evaluation should always be completed before dental or surgical intervention is performed and all excised tissue should be examined microscopically.

Cholesterol↗

PubMed1989

Mixed gangliocytoma-adenoma: a distinct neuroendocrine tumor of the pituitary fossa.

A mixed gangliocytoma-adenoma occurring in the pituitary fossa of a patient who presented with acromegaly, galactorrhea, and headaches is described. Immunohistochemical studies demonstrated the gangliocytic portion of the tumor to be composed nearly entirely of ganglion cells enmeshed in their neuritic processes and disclosed focal presence of growth hormone and prolactin-secreting cells in the adenoma. Ultrastructurally, some of the larger ganglion cells contained (and were often filled with) zebra-like bodies, while the adenoma was shown to be sparsely granulated with numerous fibrous bodies. These findings support the term of mixed gangliocytoma-adenoma for these rare intrasellar tumors and provide additional support for their nature as independent neuroendocrine units.

Adenoma↗

PubMed1989

Thymidine labeling index and Ki-67 growth fraction in lesions of the breast.

Thymidine labeling index (TLI) and Ki-67 growth fraction (KGF) are two indicators of proliferative activity in breast cancer. The authors examined the relationship between TLI and KGF in 36 breast lesions (28 invasive ductal carcinomas and 8 benign lesions). TLI and KGF values were determined in separately labeled tissue sections as well as in frozen tissue sections labeled with both Ki-67 and tritiated thymidine. In separately labeled sections of carcinoma mean TLI was 6.8 while mean KGF was 16.0. For double-labeled sections of carcinoma mean TLI and KGF values were 6.1 and 16.4, respectively. Strong correlation between TLI and KGF of malignant tumors was found by both methods: r = 0.90 (P less than 0.001) for separately labeled sections, and r = 0.96 (P less than 0.001) for double-labeled sections. In double-labeled sections of benign lesions strong correlation between TLI and KGF also was observed (r = 0.94, P less than 0.001); however, in separately labeled benign breast tissue there was no significant correlation between TLI and KGF (r = 0.38). This may have been the result of variable sampling of small proliferative foci in separate sections of benign breast tissue. The strong correlation between TLI and KGF in breast carcinoma suggests that KGF may have prognostic implications similar to those of the TLI.

Antibodies, Monoclonal↗