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Biomedical subjects

M L Davis

Publications and source records attributed to M L Davis.

At least 37 records · Page 2Linked to original sources
PubMed1984

Single-fraction palliative pelvic radiation therapy in gynecologic oncology: 1,000 rads.

The management of the patient with advanced gynecologic malignancies presents multiple problems for the gynecologic and radiation oncologists involved in their care. When palliative management only is indicated, conventional treatment protocols occupy a significant portion of the patient's remaining life span, often times with associated morbidity. Single-fraction external radiation therapy, consisting of 1,000 rads to the whole pelvis, was used in 30 patients with advanced gynecologic malignancies to palliate locally advanced pelvic disease. Alleviation of symptoms and maintenance of a reasonable quality of life were obtained in all patients. No untoward acute side effects were observed. Thirteen patients are alive from 2 to 19 months after treatment, with a mean overall survival after treatment of 8.4 months. It is concluded that this regimen should be considered as the palliative therapy of choice for certain patients with advanced gynecologic malignancies.

Adult↗
PubMed1984

Morphology and ultrastructure of the distal airway epithelium in the guinea pig.

The distal airways, defined anatomically as the region of the respiratory system including the terminal bronchioles through alveoli, were characterized in the guinea pig by means of light microscopy and by both scanning and transmission electron microscopy. The epithelium of the terminal bronchioles was comprised of two cell types. Ciliated cells were cuboidal and contained long thin microvili, ellipsoid mitochondria, and both rough and smooth endoplasmic reticulum. Nonciliated (Clara) cells were dome-shaped and usually protruded into the bronchiolar lumen. Numerous large mitochondria, granules of varying density, and crystalloid inclusions were notable in nonciliated cells. Respiratory bronchioles were characterized by a smooth-surfaced, low cuboidal epithelium. The cells in this region contained the crystalloid material found in terminal bronchioles, numerous large mitochondria, lysosomelike inclusions, and unusual tubular structures arranged in a matrix. The epithelium became progressively squamous toward the alveolar duct, where transition from bronchiolar cells to pneumocytes occurred. Transitional zones consisted of cells which, in addition to the above-mentioned structures, contained inclusions with internal laminations. These inclusions were structurally similar to the lamellar bodies observed in typical type II pneumocytes of the alveoli. The epithelium of both the alveolar ducts and alveoli was composed of type I and type II pneumocytes. Classical type I pneumocytes were squamous and very similar in cytoplasmic characteristics to the endothelial cells of the adjacent capillaries. Type II pneumocytes were characterized by the presence of lamellar bodies and numerous mitochondria.

Animals↗
PubMed1984

Monoclonal antibodies to a monkeypox virus polypeptide determinant.

Three monkeypox virus (MPV) antibody-secreting murine monoclones were characterized as being of the immunoglobulin G1 isotype, gave a 4+ reaction in the indirect fluorescent-antibody test, gave a positive reaction in the enzyme immunoassay, and did not neutralize MPV. These monoclonal antibodies were determined by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis transblot method to react to a 15,500-molecular-weight MPV polypeptide. This reactivity could not be removed by adsorption to a vaccinia virus-infected cell suspension. The three monoclonal antibodies were specific for MPV when tested against epidemiologically unrelated isolates of cowpox virus, variola virus, vaccinia virus, and MPV.

Animals↗
PubMed1983

Alveolar bone necrosis and tooth loss. a rare complication associated with herpes zoster infection of the fifth cranial nerve.

Eleven case reports involving herpes zoster infection associated with alveolar bone necrosis and tooth loss were reviewed in order to develop a patient profile for this rare combination of physical findings. The clinical course of a 56-year-old white woman with herpes zoster infection of the fifth cranial nerve and related alveolar bone necrosis, tooth loss, and oroantral fistula development is reported. The etiology and management of herpes zoster infection associated with destructive oral sequelae are discussed.

Alveolar Process↗
PubMed1983

Early appearance of donor-type antigen-presenting cells in the thymuses of 1200 R radiation-induced bone marrow chimeras correlates with self-recognition of donor I region gene products.

The thymus exerts a potent influence on the development of I region self-recognition and antigen recognition by T cells. The mechanism by which the thymus acts on nascent T cells is unknown. It is assumed, however, that a cell interaction between the developing T cell and an la antigen-bearing cell in the thymus is involved. There are several candidates for the critical thymic cell; thymic epithelial, nurse, and antigen-presenting cells (APC) or dendritic cells. Because thymic epithelial cells derive from the third pharyngeal pouch and thymic APC derive from bone marrow, radiation-induced bone marrow chimeras allow the artificial creation of a chimeric thymus gland in which thymic epithelial cells and APC can be genetically different. We made radiation-induced bone marrow chimeras (F1 leads to P) using supralethal radiation doses (1200 R) and found bone marrow donor- (F1) type APC in the thymuses 3 wk after radiation. When such mice fully reconstitute their immune systems, their T cells behave as donor F1 phenotype T cells. Thus, the I region self-restriction and antigen-recognition repertoire of the T cells correlates with the genotype of the bone marrow-derived thymic APC, not the thymic epithelial cell.

Animals↗
PubMed1983

Radiation exposure and associated risks to operating-room personnel during use of fluoroscopic guidance for selected orthopaedic surgical procedures.

Because of the increased use of fluoroscopic guidance techniques in certain orthopaedic surgical procedures, surgeons and other operating-room personnel who are involved in these procedures are voicing growing concern over possible associated radiation health hazards. Using thin-layer lithium fluoride chips for thermoluminescence dosimetry, we directly measured the radiation exposure encountered by the primary surgeon during seven operative procedures that were done utilizing fluoroscopic guidance techniques. Dosimetry studies were also carried out using a tissue-equivalent phantom model to determine the directions of maximum scatter radiation. These studies indicated that the standard protective apron that is commonly worn during the use of fluoroscopy provides adequate protection to most of the body; however, the surgeon is exposed to significant levels of scatter radiation to the head, neck, and hands, Dosimetry studies showed that positioning the fluoroscopic beam vertically to the fracture site of the supine patient, with the x-ray source posterior to the patient, provided the lowest levels of scatter radiation to the surgeon in the normal working position.

Fluoroscopy↗
PubMed1977

Attempts to purify hemopoietic stem cell enrichment in bone marrow by use of glass wool filtration.

This study is about enrichment of hemopoietic stem cell concentration in mouse bone marrow by use of a glass wool filtration technique. Maximum stem cell concentration was accomplished when filtration conditions were as follows: (1) support medium supplemented to 15% with fresh serum from syngeneic donors; (2) no incubation time allowed for cells on the columns; and (3) an operational temperature of 24 degrees C. With these conditions, stem cell concentrations were increased 5,4-fold relative to the concentration in untreated marrow.

Animals↗
PubMed1974

Amount and distribution of study in a personalized instruction course and in a lecture course.

The rapid proliferation of courses based on Keller's Personalized System of Instruction (PSI) calls for a prompt evaluation of the relative costs involved in PSI and more traditional forms of college instruction. To determine the cost in student time required by a course taught with PSI relative to lecture, students did their studying in a special Study Center where course materials could be used but not removed. Students in the PSI section spent an average of about 50% more time in the Study Center (46 hr) than did students in the lecture section (30 hr), but that difference was made up by the lecture students spending an average of 20 hr attending lectures. Thus, total preparation time was about the same. PSI students scored slightly higher on common course exams, and while college entrance exam scores correlated highly with course exam scores, Study Center time was reliably related to course exam score only for PSI students. An analysis of the study records of individual students revealed that PSI produced fairly regular patterns of study by all students, while lecture students varied greatly in their patterns.

Journal Article↗
PubMed1973

Separation of spleen colony forming units (CEU-S) from mouse bone marrow cells using velocity sedimentation in an isokinetic gradient of Ficoll in tissue culture medium.

Spleen colony forming cells (CFU-S) from mouse bone marrow were concentrated using velocity sedimentation in an isokinetic gradient of Ficoll (polysucrose) in tissue culture medium. Following separation, CFU-S were found as a sharp modal population of cells which was discrete from the modal populations of lymphocytes and other cell types. Despite the wide separation of lymphocytes, granulocytes and CFU-S in the density gradient, there was no appreciable resolution of CFU-S specifically committed to erythroid, granulocytic or undifferentiated colony formation. This suggests that committed stem cells either share identical physical properties or are not detected by the spleen colony assay. In the purest fractions from the isokinetic gradient, CFU-S were 2.8- to 4.7-fold purified when compared with mouse bone marrow before separation.

Animals↗
PubMed1972

Solid-phase radioimmunoassay of total and influenza-specific immunoglobulin G.

An antigen-antibody system of polystyrene tubes coated with immunoglobulin antibody was used for quantitating immunoglobulins. A similar radioimmunoassay method was adapted for a viral antigen-antibody system. The viral system can be used for quantitating viruses and for measuring virus-specific antibodies by reacting with (125)iodine-labeled anti-immunoglobulin G (IgG). Optimal conditions for coating the solid phase, specificity of the immune reaction, and other kinetics and sensitivities of the assay method were investigated. Comparison of direct and indirect methods of assaying for immunoglobulins or viral antibody indicates that the indirect method is more sensitive and can quantitate a minimum of 0.037 mug of IgG per ml. Results of solid-phase radioimmunoassay for influenza antibody correlate well with hemagglutinin antibody titers but not with complement-fixing antibody titers. Radioimmunoassay results for influenza antibody by solid phase are likewise in agreement with results by the carrier precipitate radioimmunoassay method. The simplicity, reproducibility, and versatility of the solid-phase procedure make it diagnostically useful.

Animals↗
PubMed1972

Examination performance in lecture-discussion and personalized instruction courses.

Students enrolled in a Psychology of Learning course were assigned to either a lecture section, one of two similar personalized instruction sections, or a fourth section that rotated across all three teaching procedures. All students took identical midterms and a final examination. After correcting test performance for differences in the cumulative grade point average of students in the four sections, examination performance of students in the personalized sections was found to be superior to that of students in the lecture section. An analysis of class section examination performance by item type revealed that students in the lecture section scored lower on all item types, but the greatest differences occurred on items that required written responses (essay and fill-in items) rather than recognition responses (multiple choice items). A gross analysis of student performance in the class rotated across the instructional procedures suggests that personalized instruction had its greatest impact on students with "average" to "poor" academic records.

Journal Article↗