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Biomedical subjects

S E Shackney

Publications and source records attributed to S E Shackney.

18 recordsLinked to original sources
PubMed1992

Sequential paraformaldehyde and methanol fixation for simultaneous flow cytometric analysis of DNA, cell surface proteins, and intracellular proteins.

A cell fixation and permeabilization procedure consisting of sequential paraformaldehyde and methanol was evaluated and found suitable for concomitant flow cytometric quantification of total cellular DNA, immunofluorescence measurements of cell surface proteins, and immunofluorescence measurements of intracellular proteins. Paraformaldehyde/methanol-fixed cells exhibited significantly greater intracellular antitubulin immunofluorescence than cells fixed with paraformaldehyde or methanol alone (p less than 0.002) and significantly greater intracellular antitubulin immunofluorescence than cells fixed with methanol followed by paraformaldehyde (p less than 0.006). With paraformaldehyde/methanol fixation, cell morphology was well preserved and forward and right angle light scatter properties were sufficiently well maintained to permit gating on these parameters. Cell surface marker staining with fluorescent anti-leukocyte antibodies was unaffected by fixation with paraformaldehyde/methanol. Paraformaldehyde effects on the intensity of DNA staining with propidium iodide were dependent on paraformaldehyde concentration and fixation temperature; these effects were least pronounced at low paraformaldehyde concentrations (0.25% or less), and at temperatures lower than 37 degrees C. Paraformaldehyde fixation may result in differences in propidium iodide staining of DNA in some diploid cells, which may produce small spurious aneuploid peaks in normal peripheral blood leukocytes. Paraformaldehyde fixation also produces an apparent increase in the DNA index of aneuploid cell populations in comparison with methanol fixation, particularly when the DNA index exceeds 1.5. Occasionally, this paraformaldehyde fixation-induced effect is useful in identifying biologically distinct near-diploid subpopulations in tumors.

Aneuploidy↗
PubMed1979

Thymosin fraction V and intensive combination chemotherapy. Prolonging the survival of patients with small-cell lung cancer.

Patients with small-cell bronchogenic carcinoma who received intensive remission-induction chemotherapy randomly received either thymosin fraction V, 60 mg/sq m or 20 mg/sq m twice weekly, or no thymosin treatment during the initial six weeks of chemotherapy. Chemotherapy was then continued for two years. Thymosin administration did not increase the complete response rate. Patients receiving thymosin, 60 mg/sq m, had significantly prolonged survival times relative to the other treatment groups. This benefit was due to prolonged relapse-free survival in complete responders to treatment. The mechanism by which thymosin increased survival duration is unclear but may relate to restoration of immune deficits due to disease or treatment.

Antineoplastic Agents↗
PubMed1979

Cyclic alternating combination chemotherapy for small cell bronchogenic carcinoma.

Sixty-one protocol-eligible patients with small cell bronchogenic carcinoma received cyclic alternating combination chemotherapy with two or three non-cross-resistant drug combinations. No chest or prophylactic brain radiation therapy was used. Twenty-eight months after starting treatment, disease-free survival was 23% for patients achieving a complete response (CR) and 13% overall. Initial treatment consisted of high-dose cyclophosphamide, methotrexate, and CCNU (CMC) for 6 weeks. Patients then received vincristine, adriamycin, and procarbazine (VAP) for 6 weeks. The addition of VAP increased the CR rate from 42% to 74% in limited-disease patients and from 24% to 36% in extensive-disease patients. Half of the patients were randomized to a third combination of VO-16-213 and ifosfamide. These patients were cycled at 6-week intervals through the three drug regimens while the remaining patients were cycled between CMC and VAP. The addition of VP-16-213 and ifosfamide did not increase the CR rate or prolong survival. Only complete responders survived beyond 24 months. Sequential use of non-cross-resistant drug combinations represents one method for increasing the CR rate.

Antineoplastic Agents↗
PubMed1979

The T-lymphocyte as a diploid reference standard for flow cytometry.

T-lymphocytes prepared from the peripheral blood of normal individuals exhibit uniform postmitotic DNA contents that are constant from individual to individual when fixed in ethanol and stained with mithramycin, or when fixed in formalin and stained with acriflavine-Feulgen and analyzed by flow microfluorometry. T-lymphocytes fixed by either method are stable on storage for several months. These cells are suitable for use as an external diploid reference standard for flow cytometric detection of cells with abnormalities in postmitotic content exceeding 5% of diploid reference. Cells with abnormalities in postmitotic DNA content of less than 5% can be detected in mixtures containing both normal and malignant cells by multiparameter analysis.

DNA↗
PubMed1979

A dynamic interpretation of multiparameter studies in the lymphomas.

A general approach to the analysis of cellular life cycle traverse patterns is described. This approach is exemplified in human lymphomas, using Coulter volume and DNA content measurements obtained by flow cytometry. Among the B-cell tumors the large-cell lymphomas generally show larger fractions of DNA-synthesizing cells and a higher degree of proliferative activity than the small B-cell lymphomas. Paired cell-by-cell measurements of Coulter volume and DNA content can be used to distinguish large aneuploid tumor cells from smaller diploid cells in mixed cell populations. The paired measurements can also be used to explore the kinetic properties of subpopulations within individual tumor samples. It can be shown that within individual lymphoma samples there are subpopulations of large cells that have greater proliferative activity than the small cells.

Cell Cycle↗
PubMed1978

Growth rates of small cell bronchogenic carcinomas.

In reviewing a series of 144 patients with small cell bronchogenic carcinoma, 12 were found to have serially measurable roentgenographic lesions prior to therapy. Although caliper-based measurements and a silhouette cutout method gave comparable sets of tumor doubling time data, inter-observer variability was less with the silhouette cutout method. Tumor doubling times in small cell bronchogenic carcinoma ranged between 25 and 160 days, with a median of 77 days, a log mean of 81 days, and an arithmetic mean of 91 days. There was no apparent relation between tumor doubling time and tumor location, histologic subtype, response to therapy, or patient survival. The data indicate that small cell bronchogenic carcinoma of the lung is a relatively slowly growing tumor. Assuming that late subclinical disease exhibits growth characteristics that are similar to those seen in the clinical stages of growth, it can be estimated that residual body tumor burdens of 1 X 10(6) cells may be followed by tumor recurrence times of 2 years or longer; the likelihood of "cure" should not be entertained in patients with disease-free intervals shorter than 4-5 years.

Carcinoma, Bronchogenic↗
PubMed1978

Growth rate patterns of solid tumors and their relation to responsiveness to therapy: an analytical review.

The clinical doubling times of human solid tumors are reviewed. Methods are also described for estimating subclinical tumor doubling times, and these methods are applied to Wilms' tumor, choriocarcinoma, Burkitt's tumor, and breast cancer. Rapidly growing tumors are often responsive to therapy, and such complete responses are often quite durable. Slowly growing tumors respond less favorably to therapy, and responses are generally not durable. Rapidly growing tumors in advanced stages are similar in their response behavior to the slowly growing tumors. A strategy based on cell kinetics principles and tumor doubling time data is proposed for improving therapeutic results in responsive tumors. Data on clinical and subclinical tumor doubling times are used to distinguish early recurrences from late recurrences in a given tumor type. Early recurrences call for intensification of induction therapy, whereas late recurrences call for prolongation of consolidative therapy. This strategy may also apply in adjuvant therapy of slowly growing tumors.

Humans↗
PubMed1978

Streptozotocin in advanced small cell bronchogenic carcinoma: an ineffective nonmyelosuppressive agent.

Thirteen patients with advanced small cell bronchogenic carcinoma (SCBC) received at least three weekly cycles of iv streptozotocin (STZ). There were no objective responses. Four patients progressed by the third week of therapy and an additional eight by the fourth week. Toxicity was acceptable especially in view of the extensive prior therapy. STZ is unlikely to be of benefit in combination chemotherapy regiments for SCBC.

Aged↗
PubMed1977

Rapid grain and cell counting for cell kinetic studies.

A commercially available bacterial colony counter has been adapted for the counting of radioautographic grains over individual cells in smears and for the counting of cells in histologic sections. For radioautographic grains, the correlation coefficients between counts obtained visually by 2 observers and between counts obtained visually and with the use of the instrument were similar (r=0.999 and r=0.998, respectively). The instrument counts were obtained more rapidly than the visual counts and were associated with less observer fatigue. Even though the performance of the instrument in counting cells in mouse bone marrow sections was less accurate than that in counting radioautographic grains, a good estimation of marrow cell number was obtained (r=0.968). Data on bone marrow cellularity were obtained far more rapidly than those with semiquantitative methods.

Autoradiography↗
PubMed1977

Lethal and sublethal effects of hydroxyurea in relation to drug concentration and duration of drug exposure in sarcoma 180 in vitro.

The lethal and sublethal effects of hydroxyurea were studied in Sarcoma 180 in vitro in relation to drug concentration and drug exposure duration using cloning methods, radioautography, and flow microfluorometry. It was shown that postperturbation changes in radioautographic labeling intensity reflected real changes in the rate of DNA synthesis in individual cells. The data suggest that both the lethal and sublethal effects of hydroxyurea are dependent on the rate of DNA synthesis. These findings have important implications for the interpretation of DNA content distributions under perturbation conditions and for the development of drug treatment regimens that are based on cell kinetics.

Animals↗
PubMed1976

The effects of colcemid on mouse bone marrow.

Following Colcemid administration, mitoses accumulate preferentially in the subendosteal region of the bone marrow of the mouse. This finding suggests that the most rapidly proliferating cells are localized to the subendosteal region, and complements previous radioautographic studies which have demonstrated a corresponding labelling gradient in the marrow. Quantitative estimates of cell cycle time by the stathmokinetic method were precluded by the presence of significant Colcemid induced interphase cell loss. Colcemid also affected cell differentiation in the marrow. Following Colcemid administration there was a fall in mature granulocytes in the marrow, and a concommitant rise in marrow megakaryocytes.

Animals↗
PubMed1976

The effects of colcemid on hematopoiesis in the mouse.

Colcemid was found to induce a dose and schedule dependent marrow magakaryocytosis and peripheral thrombocytosis. The response could be divided into early and late components. The early component appears to have been due to a direct stimulatory effect, probably by enhancement of endoreduplication in metaphase arrested megakaryocyte precursors. The ealy stimulatory response was blunted on toxic drug schedules. In contrast, the late component of the thrombopoietic response was demonstrated best on the most toxic drug schedules. It coincided temporally with the reactive restoration of the mononuclear marrow and blood cell elements, respectively. Thus, the late component appears to be a nonspecific rebound phenomenon. On comparing the thrombopoietic properties of Colcemid with those of the vinca alkaloids in experimental systems, the former appears to have a more favorable therapeutic index. The data suggest that colchicine and its derivatives may be useful agents in the treatment of clinical thrombocytopenic states.

Animals↗
PubMed1976

Role of radioautographic studies in clinical investigative oncology and chemotherapy.

Three clinical areas are identified in which radioautographic studies may be of practical usefulness. First, human tumors can be classified according to the predominant pattern of DNA synthesis in the slowly proliferating cell fraction. This classification scheme groups carcinoma of the breast and ovary together, melanoma and carcinoma of the lung together, and places acute adult leukemia in a separate class. If there are correlations between kinetic characteristics and drug response behavior, this classification scheme may simplify the clinical study of new drugs and drug combinations. Second, changes in the labeling index (LI) and/or cell labeling intensity may serve as useful guides in drug scheduling. There are circumstances where changes in cell labeling intensity may be more reliable than changes in the LI. Third, cell morphology, population kinetics, and clinical course may all be correlated in certain human tumors, particularly the lymphomas. Supporting evidence in Sézary's syndrome is presented.

Acute Disease↗
PubMed1975

The radioautographic transfer function and its implications for radioautographic methodology.

A function was developed to relate the radioautographic detectability of tritiated thymidine to its incorporation into nuclear DNA under various experimental and specimen processing conditions. The implications of this function for the interpretation of cell kinetic studies were outlined, and its implications for radioautographic methodology were discussed. The standardization of radioautographic methods for facilitation of comparisons of data obtained from different sources under dissimilar experimental conditions was discussed.

Autoradiography↗
PubMed1975

Kinetic-microarchitectural correlations in the bone marrow of the mouse.

Transverse histologic sections of bone marrow obtained from mice that were sacrificed by perfusion fixation at intervals following tritiated thymidine injection were studied by means of radioautography. A kinetic gradient was demonstrated across the marrow section, with the highest proliferative rate in the subendosteal region. Megakaryocytes were shown to originate from the rapidly proliferating subendosteal cells. The immediate proliferating precursors of mature granulocytes were slowly proliferating cells found predominantly in the central region of the marrow. It was concluded that in the steady state there must be a migration of cells from the subendosteal region to the central region with concomitant growth retardation of the migrating cells.

Animals↗