Biomedical subjects

L Dressler

Publications and source records attributed to L Dressler.

At least 19 recordsLinked to original sources

PubMed1995

The need for epidemiologic studies of in-situ carcinoma of the breast.

The purpose of this paper is to present background information on carcinoma in situ (CIS) of the breast and to provide a theoretical framework for planning epidemiologic studies which may further our understanding of breast cancer. Two types of epidemiologic studies are needed which incorporate CIS of the breast: (i) case-control studies, in which in-situ lesions serve as disease outcomes (endpoints), and (ii) cohort studies and clinical trials, in which diagnosis of in-situ carcinoma serves as a starting point for patient treatment and follow-up. Case-control studies focusing on the causes of CIS have distinct advantages: if risk factors for cancer contribute to pathways involving some intermediate stages but not others (e.g. comedo-type but not non-comedo-type DCIS; LCIS versus DCIS), the use of precursor lesions may more clearly reveal risk factor associations than studies of invasive breast cancer alone; epidemiologic studies of precursor lesions are conducted closer in time to the exposures suspected to be causes and may reduce recall bias or other forms of misclassification; genetic alterations in early lesions are more likely to represent causal events in development of the malignant phenotype. Population-based case-control studies of CIS may thus prove useful in understanding breast cancer etiology and designing preventive strategies. CIS patients identified for case-control studies may be followed up over time as a cohort. Cohort studies (and clinical trials) of CIS aim to elucidate mechanisms influencing progression of CIS to invasive cancer as well as to evaluate effectiveness of specific treatment modalities. Although the majority of CIS lesions of the breast are ductal carcinoma in situ (DCIS), epidemiologic studies which also include patients with lobular carcinoma in situ (LCIS) address potential differences between DCIS and LCIS with respect to both etiology and progression.

Breast Neoplasms↗

PubMed1994

Prognostic factors in early breast carcinoma.

Several investigators, the SEER data, and the ECOG/Intergroup study have shown that patients with small tumors (< 0.5 cm) have a recurrence rate of less than 2%, compared to 20-25% for large tumors (> or = 5 cm). Nuclear grade and tumor differentiation are established indicators; however, the interobserver lack of concordance has thwarted their use in clinical trials. The presence of peritumoral lymphatic and blood vessel invasion (PLBI) is associated with a relative risk of recurrence of 4.7. The predictive value of the presence of hormone receptors in tumors is associated with a favorable disease free and overall survival difference of 8-10%; however, this advantage is being eroded by the early appearance of other factors, such as the epidermal growth factor receptor (EGFR), proliferative capacity (S-phase), nuclear grade, and HER-2/neu oncogene. Concordance among the different methods of hormone-receptor assay (immunocytochemical, sucrose gradient, and dextran-coated charcoal) is essential to refine the true value of these factors. DNA flow cytometry measurements of ploidy (DNA content) and S-phase fraction are the most characterized of the prognostic factors. There are conflicting reports regarding the clinical significance of ploidy status, while measurements of S-phase fraction clearly indicate a robust association with disease free and overall survival. Our data continue to show that S-phase, but not ploidy, can predict time to recurrence significantly in untreated patients, even when data are stratified for tumor size. HER-2/neu oncogene is expressed in about 50% of ductal carcinoma in situ and 14% of invasive ductal carcinoma. The presence of this oncogene at high copy number may be a useful independent marker of poor prognosis and may be associated with drug resistance and correlated with tumor recurrence and shorter survival. EGFR could be measured in most breast tumors, and the level of its expression has inversely correlated with estrogen receptor protein expression. The value of EGFR as a predictor of prognosis remains controversial and is still being investigated. Cathepsin-D provides a provocative biologic rationale but is hindered by different and incongruent methods of analysis. The majority of large studies with more than 3-years' follow-up suggests that high cathepsin-D levels may be predictive of greater recurrence and lower survival. Angiogenesis has been implicated as a critical component of the metastatic process. Early studies show that tumor angiogenesis is an independent and highly significant prognostic indicator, and its presence may suggest the selection of "anti-angiogenic therapy."(ABSTRACT TRUNCATED AT 400 WORDS)

Breast Neoplasms↗

PubMed1994

Signet ring cell adenocarcinoma of prostate.

Primary signet ring cell adenocarcinoma of the prostate is a rare malignancy with a total of 13 cases reported to date in the English literature. We report a very unusual case of signet ring adenocarcinoma of the prostate occurring in a patient who presented initially with irritative voiding symptoms and a bladder mass. Results of immunohistochemical, flow cytometric, and cytogenetic analyses of the tumor are presented.

Carcinoma, Signet Ring Cell↗

PubMed1991

Clinical applications of cytometry: 5th annual meeting.

The 5th annual Clinical Applications of Cytometry meeting was held September 12-15, 1990 in charleston, SC. The theme which emerged repeatedly throughout the meeting was the need to take full advantage of the quantitative power of cytometry to provide the most useful clinically relevant diagnostic and prognostic information. Greater quantitative power is based on careful and reproducible standards and quality control. The same principles, albeit with somewhat different approaches, apply to cell surface immunofluorescence analysis, DNA measurements, and image cytometry assessments. Monoclonal antibody probes against oncogenes, others against lymphokines within the Golgi, and a novel fluorogenic substrate designed to quantitate the activity of a mitochondrial enzyme were exciting developments described at the meeting.

Autoimmune Diseases↗

PubMed1990

Aggressive jejunal lymphoma of large granular lymphocytes. Immunohistochemical, ultrastructural, molecular, and DNA content analysis.

An unusual large cell lymphoma of the proximal jejunum with large granular lymphocyte (LGL) morphologic characteristics and T-helper/inducer cell phenotype is described. Although the cells strongly expressed Leu-7 (HNK-1), studies with antibodies directed against the more specific natural killer (NK) antigens, CD16 (Leu-11) and Leu-19, were negative. Ultrastructural analysis of the neoplastic cells demonstrated substantial numbers of electron-dense granules and rare parallel tubular arrays. Clonal rearrangement of the T-cell receptor beta chain gene and germline configuration of the immunoglobulin heavy chain gene confirmed the T-cell origin of the neoplastic cells. This lymphoma pursued an aggressive clinical course, with rapid dissemination to the lungs and central nervous system. DNA content analysis indicated that a similar DNA aneuploid population was present in the jejunal primary and lung tissue at recurrence. There was no evidence of nodal, peripheral blood, splenic, or bone marrow involvement. Morphologic and functional similarities between the lymphoid tissues of the gastrointestinal tract and lung have previously prompted a classification of the immune system into distinct peripheral somatic and mucosal components. Based on the distribution and migratory properties of the tumor cells in this case, the authors propose that this lymphoma arose from a minor mucosa-associated LGL subset that may be unrelated to circulating LGLs. In addition, these observations emphasize that prominent granulated cytomorphologic features may be seen in neoplastic disorders with the T-helper/inducer phenotype, as well as in the more widely recognized lymphoproliferative disorders of NK and cytotoxic/suppressor cell types.

Aged↗

PubMed1989

High-grade non-Hodgkin lymphoma relapsing as low-grade follicular lymphoma: so-called downgraded lymphoma.

Evolution of low-grade Non-Hodgkin Lymphoma (NHL) into a more aggressive neoplasm is a common, well-documented event in NHL. The reverse process, in which a less aggressive component becomes evident during the course of treatment for a higher-grade NHL, has only recently been recognized. This lymphoma "downgrading" has been reported at the time of relapse in both radiation- and chemotherapy-treated patients who initially presented with high- or intermediate-grade lymphoma. The etiology of this unusual transformation has not yet been determined. We present the clinical, morphologic, immunologic, and flow-cytometric features of a patient with diffuse immunoblastic lymphoma who achieved a complete response to chemotherapy and then relapsed with follicular small-cleaved-cell lymphoma 3 years later. Morphologic and immunophenotypic findings suggest that both immunoblasts and small cleaved cells were present in the initial biopsy. DNA content analysis of the initial and relapse biopsies suggests that the immunoblastic component was more susceptible than the small cleaved cells to the chemotherapy that the patient received. Successful eradication of the rapidly proliferating immunoblasts with survival of less rapidly proliferating small cleaved cells may account for the unusual histologic transformation seen in this case.

Adult↗

PubMed1989

Hematogones: a multiparameter analysis of bone marrow precursor cells.

Morphologically distinct lymphoid cells with homogeneous, condensed chromatin and scant cytoplasm can be observed in large numbers in the bone marrow of children with a variety of hematologic and nonhematologic disorders. In some patients, these cells may account for greater than 50% of the bone marrow cells, creating a picture that can be confused with acute lymphoblastic leukemia (ALL) or metastatic tumor. Although originally called hematogones (HGs), a variety of other names have been proposed for these unique cells. The clinical significance of expanded HGs has not been resolved, and the biologic features of these cells are incompletely described. In this study, we correlate the clinical, morphologic, cytochemical, flow cytometric, molecular, and cytogenetic properties of bone marrow samples from 12 children with substantial numbers of HGs (range 8% to 55% of bone marrow cells). Diagnoses in these patients included anemia, four; neutropenia, one; anemia and neutropenia, one; idiopathic thrombocytopenic purpura, two; retinoblastoma, two; Ewing's sarcoma, one; and germ cell tumor, one. Flow cytometric analyses of bone marrow cells demonstrated a spectrum extending from early B-cell precursors (CD10+, CD19+, TdT+, HLA-Dr+) to mature surface immunoglobulin-bearing B cells in these patients, corroborating our morphologic impression of HGs, intermediate forms, and mature lymphocytes. DNA content was normal, and no clonal abnormality was identified by either cytogenetic or immunoglobulin and T-cell receptor (TCR) gene rearrangement studies. Follow-up ranged from 3 months to 3 years. None of the patients has developed acute leukemia or bone marrow involvement by solid tumor. The possible role of HGs in immune recovery and hematopoiesis is presented.

Biomarkers, Tumor↗

PubMed1985

[Heart valve replacement with myocardial revascularization].

Coexisting coronary artery insufficiency includes risks to patients with valvular heart disease, thus complicating management. In 15 patients requiring aortic or mitral valve replacement preoperative coronary angiography demonstrated severe coronary stenoses which were treated by bypass grafts with valve surgery. These combined operations turned out to be safe and effective.

Adult↗

PubMed1979

The optimization of the pulse delivered by the pacemaker.

The results of stimulation threshold analysis carried out in 230 patients after the initial electrode implantation, and in 188 patients during pacemaker replacement, are presented. The electrodes investigated were the IE-60K-10 (279 cases), the IE-60-K (96 cases) and the ME-50 (26 cases). The chronic stimulation threshold voltage for the electrode IE-60K-10 (electrode surface area: 10 mm2) at a pulse width of 0.5 ms, after an electrode function time of 25 months, is 2.05 +/- 0.18 V, representing 256% of the acute threshold, and is equally as high as the chronic figure for the IE-60-K electrode (surface area: 27 mm2) measured at 2.08 +/- 0.20 V. The current threshold for the IE-60K-10 increased from 0.78 +/- 0.07 mA by 299% to 2.33 +/- 0.30 mA and was thus, as expected, lower than that of the large area electrode IE-60-K, which increased from 1.11 +/- 0.22 mA to 3.23 +/- 0.43 mA (291%). On the basis of the computation of the stimulation threshold energy and the stimulation threshold charge, a reduction of pulse duration to below 0.5 ms would not appear to make such energy-saving sense.

Electrodes, Implanted↗

PubMed1975