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Biomedical subjects

D R White

Publications and source records attributed to D R White.

At least 145 records · Page 8Linked to original sources
PubMed1977

An analysis of the Z-dependence of photon and electron interactions.

A comprehensive analysis has been completed of the dependence of photon and electron interactions upon atomic number. The calculations were specifically biased towards the application of the data to biological tissues and their substitutes. The photon interactions considered in the survey included all the partial attenuation and energy absorption cross-sections. The electron interactions analysed were collision and radiation stopping powers and angular scattering powers. The derived Z-exponents are tabulated for different energies and elemental groupings and indicate the inadequacy of existing Z-exponents. In particular, the continued use of the single exponent 3.94 for photoelectric attenuation (per atom) is put in question.

Adipose Tissue↗
PubMed1977

The formulation of tissue substitute materials using basic interaction data.

An analytical procedure has been developed for the formulation of tissue substitute materials for use with photons and electrons. This method, called the basic data method, is based upon interaction data and enables two-component substitutes to be formulated with radiation characteristics within specified limits. Another feature of the procedure is the ability, once a primary material has been chosen, to select the best corrective additives from a library of compounds. The theoretical aspects are discussed followed by a discussion of the practical applications of the method.

Electrons↗
PubMed1977

Epoxy resin based tissue substitutes.

A series of epoxy resin based tissue substitutes, simulating adipose tissue, bone, breast, lung, muscle and skin is described. Details of the physical radiation characteristics of the formulated systems are given, together with the manufacturing procedures. The versatility of the range of substitutes is discussed in terms of both investigated and projected applications in experimental radiation studies.

Adipose Tissue↗
PubMed1977

Combination chemotherapy in advanced breast cancer.: a randomized trial comparing a three-vs a five-drug program.

A prospective randomized trial was undertaken to compare the efficacy of a three-drug regimen using cyclophosphamide, methotrexate, and fluorouracil to a five-drug regimen using vincristine sulfate and prednisone in addition to cyclophosphamide, methotrexate, and fluorouracil in advanced breast carcinoma. Seventy-two patients who had received no prior chemotherapy were randomized. Thirty-eight patients received three drugs, and 34 received five-drug therapy. The objective response rates, 34% and 50% respectively, did not differ signficantly (P = .13). As expected, myelosuppression occurred in most patients, and neurotoxicity was much more common in patients receiving vincristine. Three of 12 patients treated with the five-drug regimen after progession of disease while receiving the three-drug regiment showed an objective response to the five-drug regimen.

Breast Neoplasms↗
PubMed1977

Adriamycin-methotrexate combination chemotherapy of advanced carcinoma of the cervix.

Sixteen women with advanced carcinoma of the cervix were treated with adriamycin and methotrexate. Median age on entry into the study was 51 years. Seven subjects were premenopausal, 7 postmenopausal, and 2 were within 2 years of their last menstrual period at the time of diagnosis. Median time of inclusion in the study was 3.3 months. Median survival from initial diagnosis thus far has been 39.0 months. Median survival from the institution of therapy has been 5.8 months. Of 16 evaluable patients the following results were obtained: no complete remissions (0%), 2 partial remissions (12.5%), 1 patient with stable disease (6.2%). When used in dosages which do not precipitate dangerous toxicity this therapy is not effective and in the opinion of the authors should be abandoned.

Doxorubicin↗
PubMed1976

Histiocytic medullary reticulosis with parallel increases in serum acid phosphatase and disease activity.

Two months after presenting with autoimmune hemolytic anemia, a 57-year-old man developed increased serum acid phosphatase activity. Subsequently, abnormal histiocytes were found in the bone marrow and blood, and 8 months after the onset of his illness lymph node biopsy led to the diagnosis of histiocytic medullary reticulosis. At that time the level of serum acid phosphatase activity was more than 60 times the upper limit of normal and then paralleled the activity of his disease during temporary responses to chemotherapy, rising to over 90 times normal at the time of his death 1 year after presentation. No prostatic malignancy was demonstrated by biopsies or at autopsy, and electrophoretic studies of the serum enzyme suggested that it was of extraprostatic origin. It is postulated that the acid phosphate present in the serum at levels heretofore described only in metastatic carcinoma of the prostate may have arisen from the abnormal histiocytes.

Acid Phosphatase↗
PubMed1976

Methyl-CCNU, alone and in combination with vincristine, or vincristine and methotrexate, in advanced bronchogenic carcinoma.

Ninety-two patients with advanced bronchogenic carcinoma were prospectively randomized according to performance status, histology, and extent of disease to methyl-CCNU alone; methyl-CCNU and vincristine; or methyl-CCNU, vincristine, and methotrexate. Seventy-three patients were evaluable. Randomization to methyl-CCNU alone was discontinued when only three brief "static" responses were noted in 11 patients and the survival (p less than .01) and time on study (p less than .05) were noted to be significantly less than with the combination. Two of 32 patients treated with methyl-CCNU and vincristine, and two of 30 patients treated with methyl-CCNU, vincristine, and methotrexate had mixed responses with a median of 67.5 days. A static response was seen in eight of 32 and none of 30 patients, respectively. Minimal toxicity occurred in all regimens. Methyl-CCNU alone or in combination with vincristine or vincristine and methotrexate is of limited benefit in patients with lung cancer, although our data suggest (p = 0.15) that the addition of methotrexate increases time on study and survival in patients with extensive disease.

Carcinoma, Bronchogenic↗
PubMed1976

Brain scanning in patients with recurrent breast cancer.

Brain scans were performed on 116 patients with recurrent breast cancer. Seventy-eight of 79 (98%) asymptomatic patients with recurrent disease had negative brain scans. Eleven of 37 (30%) patients with central nervous system (CNS) symptoms had scans indicative of intracranial metastases. There was no difference in the distribution of extracranial metastaic disease in patients who had positive brain scans when compared with those who did not. Brain scaning is of value in detecting intracranial metastases in patients with CNS symptoms. Brain scanning seems unnecessary, however, in the staging of patients with recurrent breast cancer who have no CNS symptoms.

Brain Neoplasms↗
PubMed1975

Leukaemoid reactions in myeloproliferative diseases. Report of two patients.

The occurrence of transient extreme neutrophilic leucocytosis, with white blood cell counts exceeding 100,000/mu-l in two adult patients with myeloproliferative diseases, polycythaemia vera and acute myelocytic leukaemia in remission, is reported. The reaction was transient, and the subsequent course of the patient's disease did not differ from that prior to the episode. Such extreme leucocytosis is rare in adults, despite the frequency of provoking conditions, and factors which predispose an individual to develop a leukaemoid reaction remain unknown. An increase in the size of the pool of proliferating granulocyte precursors accompanied by a loss of the restraining function of the marrow sinusoidal walls in myeloproliferative diseases may explain the augmented release of myeloid cells in our patients.

Female↗
PubMed1975

Binding of intracellular protein to the erythrocyte membrane during incubation: the production of Heinz bodies.

During sterile incubation of normal human erythrocytes at 37 degrees C., intracellular nonhemoglobin protein is bound to the membrane prior to hemolysis. These studies have characterized this phenomenon further. Protein binding to the membrane began after 12 hours incubation when cellular ATP was depleted and increased to 36 hours incubation. The binding was prevented by adding adenosine or glucose at the start of incubation and was arrested by adding adenosine to regenerate ATP during the course of incubation. However, protein, once bound, was not released by regeneration of ATP. The amount of protein bound was not altered by: (1) addition of Ca++ or EDTA to the medium, (2) blockade of sulfhydryl groups with N-ethylmaleimide, or (3) stabilization of heme-globin bonds by conversion of hemoglobin to cyanmethemoglobin. Conversion of hemoglobin to carboxyhemoglobin by incubations under carbon monoxide inhibited protein binding, but this appeared to be an effect of exclusion of oxygen rather than stabilization of heme-globin bonds since incubation under nitrogen had a similar effect. The morphological counterpart of this chemically-measured membrane-bound protein was visible in red cell ghosts stained with crystal violet as small membrane-associated particles resembling Heinz bodies. Sodium dodecyl sulfate acrylamide gel electrophoresis of membranes of incubated cells revealed a new protein band that was identical to globin monomers. This membrane binding of globin during incubation provides a model for the study of Heinz body formation in clinical disorders.

Adenosine↗
PubMed1973

Harold Edgar Harris.

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History, 20th Century↗