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Biomedical subjects

R W Miller

Publications and source records attributed to R W Miller.

At least 73 records · Page 4Linked to original sources
PubMed1992

Influence of masker bandwidth on binaural masking level differences.

Masking level differences (MLDs) were investigated using masking noise with 160 Hz (amplitude-modulated noise) and 600 Hz (filtered-random noise) bandwidth. One hundred normally hearing subjects received the MLD test under both types of noise. Significant differences between noise types were observed in both N0S pi and N pi S0 conditions; MLDs were larger in amplitude-modulated noise. Consideration of these differences would indicate that older MLD norms based solely on filtered-random noise are invalid for amplitude-modulated noise especially where bandwidth differences in the noise exist. Were the norms for 600-Hz-wide filtered-random noise to be applied to results of MLD testing performed using 160-Hz-wide amplitude-modulated noise, patients with lesions in the central auditory pathway might exhibit normal or borderline normal results. Clinical MLD norms established on one type of noise should not be used to interpret MLD results obtained using a different type of noise.

Adolescent↗
PubMed1991

Oncogene expression in cervical intraepithelial neoplasia and invasive cancer of cervix.

Expression of the oncogenes Ha-RAS, c-MYC, and ERB-2 was investigated with an automated image analysis system in 12 specimens of normal cervix, 10 of cervical intraepithelial neoplasia (CIN) grade 1, 24 of CIN 3, and 10 of invasive cancer of the cervix. There was amplification of all three oncogenes in CIN 3 and invasive cancer compared with normal cervix and CIN 1. The difference was most pronounced with an antibody to the RAS p21 protein, with no overlap between CIN 3 and the normal range. This method might be useful in screening for cervical neoplasia, and for the determination of which CIN lesions require treatment.

Carcinoma in Situ↗
PubMed1991

An isocentric chair for the simulation and treatment of radiation therapy patients.

There are a variety of clinical situations in which patients undergoing radiation therapy can benefit from being treated in an upright position. The authors describe a new design for a treatment chair to assist in accomplishing this task. The present chair differs from previous designs in that it can be used with existing radiotherapy simulators as well as treatment units and that it permits isocentric setup and treatment of tumors either at the nominal source-to-axis distance (SAD) of a machine or at extended distance. This design permits treatment of mediastinal tumors as well as those of the head and neck using a variety of field arrangements including AP-PA, opposed laterals, and multiple obliques. The seat is designed on the "tool platform" principle. A wide variety of devices can be attached onto it to ensure accurate and reproducible, yet comfortable, patient positioning.

Humans↗
PubMed1990

Effects of prenatal exposure to ionizing radiation.

Prenatal exposure to ionizing radiation induces some effects that are seen at birth and others that cannot be detected until later in life. Data from A-bomb survivors in Hiroshima and Nagasaki show a diminished number of births after exposure under 4 wk of gestational age. Although a wide array of congenital malformations has been found in animal experimentation after such exposure to x rays, in humans only small head size (exposure at 4-17 wk) and mental retardation (exposure primarily at 8-15 wk) have been observed. In Hiroshima, small head size occurred after doses of 0.10-0.19 Gy or more, and an excess of mental retardation at 0.2-0.4 Gy or more. Intelligence test scores were reduced among A-bomb survivors exposed at 8-15 wk of gestational age by 21-29 IQ points per Gy. Other effects of in-utero exposure to atomic radiation include long-lasting complex chromosome abnormalities.

Abnormalities, Radiation-Induced↗
PubMed1990

Use of ivermectin to control the lesser mealworm (Coleoptera: Tenebrionidae) in a simulated poultry broiler house.

Broiler chickens were fed ivermectin at a level of 2 ppm for 5 wk to determine its efficacy against the lesser mealworm, Alphitobius diaperinus. This treatment essentially eliminated lesser mealworm larvae; no ivermectin residues were found in the livers of the treated chickens, even without a withdrawal period. However, the feeding of ivermectin may reduce body weights body weight gain and feed efficiency at older ages.

Age Factors↗
PubMed1990

Camptocormia.

Camptocormia is a disabling psychiatric condition characterized by a fixed flexion of the spine usually occurring during the stress or anticipation of battle. We present an illustrative case study and a summary of six cases. In this clinical sample the camptocormia was associated with a high likelihood of a history of significant back trauma; this lends to difficulty in assigning a diagnosis from the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R). Camptocormic patients retained in the military have a poor prognosis; rapid diagnosis and medical separation is recommended.

Adult↗
PubMed1989

Molybdenum nitrogenase of Azotobacter chroococcum. Tight binding of MgADP to the MoFe protein.

The dye-oxidized or dithionite-reduced forms of the MoFe protein of molybdenum nitrogenase of Azotobacter chroococcum were shown to bind 2 mol of MgADP/mol of protein, as determined by column equilibrium techniques. The gel-filtration elution profile of unbound Mg[14C]ADP was not symmetrical, consistent with a low rate of dissociation from the protein. Symmetrical elution profiles were observed for the oxidized Fe protein of nitrogenase, which bound 2 mol of MgADP/mol of protein. The low rate of dissociation of MgADP from MoFe protein was shown by non-equilibrium column techniques, where 1 mol of MgADP/mol of MoFe protein remained tightly bound during chromatography. Very weak binding of MgATP (less than 0.01 mol of MgATP/mol of MoFe protein) to dye-oxidized but not to dithionite-reduced MoFe protein was observed. These results are discussed in terms of their relevance to the catalytic cycle of nitrogenase catalysis.

Adenosine Diphosphate↗
PubMed1989

Effects of the chitin synthesis inhibitor diflubenzuron on development of Ascaris suum and Haemonchus contortus.

The potential of the chitin synthesis inhibitor diflubenzuron (DFB) to alter the development of the parasitic nematodes (Ascaris suum and Haemonchus contortus was investigated. DFB given orally (10 mg kg-1 per day for 30 days) to sheep inoculated with H. contortus infective larvae did not prevent the establishment of adults or affect fecal egg output. However, there was a significant (greater than 90%) decrease in the number of infective larvae recovered from fecal cultures derived from lambs harboring H. contortus adults that were treated with DFB. DFB did not affect egg hatching. Oral administration (10 mg kg-1 per day for 20 days) of DFB to swine harboring adult A. suum adults had no effect on the adult worm burden or on egg morphology, but eggs removed from worms obtained from DFB-treated swine contained less chitin than eggs removed from untreated control swine. DFB also inhibited chitin synthesis in vitro in the isolated reproductive tract of A. suum adults. These results indicate that DFB at high doses can inhibit the subsequent development of H. contortus larvae in the feces. Since H. contortus larvae lack chitin, DFB may act on these larvae by a mechanism independent of a direct effect on chitin synthesis.

Animals↗
PubMed1989

Benign familial hyperphosphatasemia.

Elevated alkaline phosphatase activity in serum suggests bone or liver disease or a neoplasm but can also indicate pregnancy or another benign condition. A family with benign hyperphosphatasemia was studied to elucidate the genetics and enzyme defect. Serum total alkaline phosphatase activity was greater than the population mean in all six family members, and more than 7 SDs above the mean in two of four offspring. Monoclonal antibodies to three alkaline phosphatase isoenzymes, intestinal, placental, and tissue nonspecific (liver/bone/kidney), demonstrated markedly increased intestinal alkaline phosphatase levels (29% to 44% of total) in all family members and significantly elevated liver/bone/kidney activity in the two offspring. Guanidine hydrochloride denaturation of the liver/bone/kidney component showed high alkaline phosphatase activity from liver in both siblings and from bone in one. The mode of inheritance in this family is obscure, but a complex regulation of the products of two different alkaline phosphatase genes seems likely. Steps toward diagnosis are suggested. Early recognition of this benign biochemical abnormality should help to avoid unnecessary diagnostic tests.

Adult↗