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Biomedical subjects

D Pinkel

Publications and source records attributed to D Pinkel.

At least 163 records · Page 9Linked to original sources
PubMed1979

Flow cytometry of mammalian sperm: progress in DNA and morphology measurement.

Variability in DNA content and head shape of mammalian sperm are potentially useful markers for flow cytometric monitoring of genetic damage in spermatogenic cells. The high refractive index and extreme flatness of the sperm heads produce an optical effect which interferes with DNA measurements in flow cytometers which have dye excitation and fluorescence light collection normal to the axis of flow. Orientation of sperm in flow controls this effect and results in coefficients of variation of 2.5% and 4.2%, respectively, for DNA measurements of mouse and human sperm. Alternatively, the optical effect can be used to generate shape-related information. Measurements on randomly oriented sperm from three mammalian species using a pair of fluorescence detectors indicate that large shape differences are detectable. Acriflavine-Feulgen stained sperm nuclei are significantly bleached during flow cytometric measurements at power levels routinely used in many flow cytometers. Dual beam studies of this phenomenon indicate it may be useful in detecting abnormally shaped sperm.

Animals↗
PubMed1978

Hydrodynamic orientation of sperm heads for flow cytometry.

Two specially shaped sample injection tubes orient flat-shaped mature sperm heads in a flow cytometer. Orientation allows control of a photometric difficulty experienced with some flow cytometers in the measurement of fluorescent and scattered light from sperm and other flat cells. Both relative DNA-stain content and a measure of cell flatness can now be determined simultaneously for each cell at the high rates possible with flow instruments.

Animals↗
PubMed1978

High resolution dual laser flow cytometry.

Flow cytometers based on optical sensing utilize external light sources and fluorescent dyes to measure one or more specific components or properties of individual cells or subcellular particles in liquid suspension. To provide for independent excitation of two dyes used in double staining experiments we have constructed a high resolution flow cytometer that uses two laser beams to provide two wavelengths of excitation. These beams are separated spatially so that cells flow through them sequentially, with a time separation of about 20 musec. Since the dyes are excited sequentially their emission occurs at different times and their emission spectra may overlap without causing any difficulty in analysis. We have developed new light collection optics that permit up to four measurements to be made on each cell. This approach greatly increases the number of dye combinations that can be used in flow cytometry, thus removing a significant limitation of single illumination instruments.

Animals↗
PubMed1977

Radiotherapy in leukemia and lymphoma of children.

Radiotherapy is important in the treatment of leukemia and lymphoma of children. In acute lymphocytic leukemia administration of cranial irradiation early during chemotherapy-induced remission prevents initial meningeal relapse. When cranial irradiation is combined with a 3-year course of multiple drug systemic chemotherapy approximately one-half of the children remain in complete remission for 5 years or more and are at little risk of relapse. Preventive cranial irradiation is effective in children with acute myelocytic leukemia, also, but this does not affect survival because of the inadequacy of chemotherapy in controlling bone marrow disease. Low dose palliative irradiation can be helpful in caring for some children with obstructive, painful or disabling leukemic lesions. In Hodgkin's disease of children radiotherapy is effective in curing stages IA, IIA, and IIIA disease and contributes to chemotherapy control of stages IIIB and IV disease. The role of radiotherapy in non-Hodgkin's lymphoma is less clear. Children with T-lymphoblastic lymphoma tend to have rapid dissemination to bone marrow and meninges and appear to benefit more from multiple agent chemotherapy and preventive meningeal irradiation. Children with B-lymphoblastic lymphoma usually benefit from cyclophosphamide therapy; the value of irradiation is yet to be established. However, radiotherapy is frequently curative in stage I B-lymphocytic nodular and histiocytic lymphomas. The indications for radiotherapy in children with leukemia and lymphoma are constantly changing. Before each child is treated the multi disciplinary evaluation and treatment team must consider the rationale in relation to the specific child and current knowledge.

Antineoplastic Agents↗
PubMed1977

Flow system fluorescence polarization measurements on fluorescein diacetate-stained EL4 cells.

We have adapted a multiparameter cell sorter to measure the distribution of fluorescence polarization in cell populations. Measurements carried out on EL4 cells show that the percent polarization of fluorescein fluorescence decreases with increasing fluorescence intensity. This inverse relationship between polarization and intensity is shown both within the cell population and by the average values of the two quantities during both the increase and decrease of fluorescence intensity. The quantitative relation between intensity and polarization is different in hypertonic than in isotonic media. These results suggest that polarization measurements carried out at a fixed time after incubation of cells with fluorescein diacetate, which is converted to fluorescein within the cells, may depend in part on the rate of fluorescein accumulation, and that agents that have been reported to change the polarization of fluorescein in living cells may do so by changing the kinetics of fluorescein accumulation.

Cell Line↗
PubMed1976

Urinary-bladder toxicity following pelvic irradiation and simultaneous cyclophosphamide therapy.

The frequency and severity of urinary-bladder toxicity were determined retrospectively in a large series of childhood cancer patients treated with either pelvic irradiation and simultaneous cyclophosphamide or cylclophosphamide with extrapelvic irradiation. Of 50 patients who received the first combination, 17 (34%) developed urinary-bladder toxicity. Eight of the 17 had transient hematuria and dysuria with complete clearing clinically after cessation of treatment; nine had chronic or intermittent hematuria which persisted after treatment was stopped and often resulted in demonstrable fibrosis and telangiectasia of the bladder. By contrast, of 60 children who received cyclophosphamide and radiotherapy outside the pelvic region, only five (8%) developed hematuria and in all instances it was transient. This comparative study demonstrates a significantly increased frequency and severity of urinary-bladder toxicity in cancer patients receiving pelvic irradiation with simultaneous cyclophosphamide.

Adolescent↗
PubMed1976

Total-body sequential segmental irradiation and combination chemotherapy for children with disseminated neuroblastoma.

Fourteen children with disseminated neuroblastoma were treated with segmental total-body irradiation and a combination of cyclophosphamide, vincristine and Adriamycin. Six others had localized tumors and were treated with either surgery alone or limited irradiation and chemotherapy. The main objective of the study was to find out if this aggressive therapy for disseminated neuroblastoma would be tolerated and would promote longer disease-free remissions and possibly, cures. Complete responses were obtained in all patients with localized tumors. Of the 14 patients with disseminated disease, three had complete responses, five had partial responses, two had objective responses, and four were classified as nonresponders. Survival rates for this group are poor. Only two patients are still alive, and the single patient who survives free of disease has had a complex clinical course that is only indirectly a result of treatment. The median survival for patients with disseminated tumor was 9 months, not appreciably different from earlier result. Although toxicity was clinically manageable, it interfered with the planned schedule of therapy. Continuous weight loss combined with severe bone marrow suppression due to irradiation prevented about 50% of the scheduled drug dose from being administered. This resulted in poor control of tumor outside of radiation ports and eventually led to progressive disease within previously irradiated sites. We conclude that irradiation used in this manner will not improve disease-free survival of children with disseminated neuroblastoma. It is essential that disseminated disease be controlled before extensive irradiation is attempted.

Antineoplastic Agents↗
PubMed1975

Combined modality therapy of acute lymphocytic leukemia.

The progressive improvement in the prognosis of acute lymphocytic leukemia has been a result of two major developments: 1) the more efficient use of chemotherapeutic agents, particularly the use of combinations of agents and the discovery that agents effective at one stage of disease may be inappropriate at another stage, and 2) the prevention with irradiation of central nervous system relapse. As many as one-half of children with this disease may enjoy long-term leukemia-free survival. However, further studies are needed to improve the efficacy and reduce the toxicity of therapy. This paper reviews the evolution of some of these studies.

Age Factors↗
PubMed1975

Capsular and vascular invasion: important prognostic factors in Wilms' tumor.

The influence of capsular and vascular invasion on prognosis was determined retrospectively in 52 children with Wilms' tumor. Local recurrence was more prevalent (0.26) in patients with rupture or capsular invasion than in any other group. Inadequate postnephrectomy irradiation or infiltration of the liver by nephroblastoma cells appeared to be predisposing factors in the development of these reccurrences. Of the 26 patients with gross or microscopic vascular invasion, 13 developed metastasis. This proportion was significantly higher than in patients without vascular involvement (p less than 0.05). These observations emphasize the importance of microscopic detection of capsular and vascular invasion in staging of Wilm's tumor.

Child↗
PubMed1975

Preoperative therapy for unresectable malignant tumors in children.

Thirty-six children with initially unresectable malignant tumors were managed with pre- and postoperative therapy combined with reduction of primary tumor burden by total or subtotal resection. The proportion of patients achieving long-term tumor-free survival after surgery was 0.48 in the Wilms' tumor group and 0.60 among patients with other regionally unresectable malignant neoplasms. These results are encouraging in an otherwise high mortality situation.

Adolescent↗
PubMed1975

Non-Hodgkin's lymphoma in children.

The clinical and pathological features of 64 children with non-Hodgkin's malignant lymphoma seen between April 1962 and June 1973 are described. Forty-one children had diffuse, undifferentiated, non-Burkitt lymphoma (lymphoblastic lymphoma). They tended to be boys under 10 years of age and their median survival was 1 year. Almost one-third are surviving for 1-11 years, most in initial complete remission. Nineteen children had diffuse, poorly differentiated, histiocytic lymphoma. They tended to be boys more than 10 years of age, their median survival was only 6 months, and only the 3 patients with Stage I peripheral node tumour survived. Two children had nodular, lymphocytic, poorly differentiated lymphoma and 2 had lymphoma resembling the Burkitt type. From our clinical and pathological observations, we conclude that non-Hodgkin's malignant lymphomata in children cannot be separated from the acute lymphocytic, histiocytic and unclassified leukaemias by cytological or histological methods. What is called diffuse, undifferentiated, non-Burkitt type, or lymphoblastic lymphoma is actually acute lymphocytic leukaemia without apparent invasion of marrow and peripheral blood by neoplastic lymphocytes at time of diagnosis. What is termed diffuse, histiocytic lymphoma is acute histiocytic leukaemia without apparent infiltration of marrow and peripheral blood at initial presentation. One could say just as well that acute lymphocytic leukaemia is Stage IV lymphoblastic lymphoma and that acute histiocytic leukaemia is Stage IV histiocytic lymphoma. Further classification of lymphocytic and histiocytic cancers by newer functional, chemical and morphological methods should include both what is called lymphocytic or histiocytic leukaemia and what is called non-Hodgkin's lymphoma as one group of diseases, susceptible to subclassification by the new methods. We recommend that Stage I lymphocytic and histiocytic cancers be treated with local irradiation. Patients with Stages II-IV tumours should receive anti-leukaemic forms of therapy including prolonged multiple agent chemotherapy and preventive central nervous system irradiation. Staging laparotomy should be considered in patients with Stage I tumour in low cervical, axillary and inguinal nodes.

Adolescent↗