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Biomedical subjects

R W Miller

Publications and source records attributed to R W Miller.

At least 19 recordsLinked to original sources

Bronchiectasis in children with lymphocytic interstitial pneumonia and acquired immune deficiency syndrome. Plain film and CT observations.

In a review of 77 HIV positive children seen between 1981 and 1990, 32 were diagnosed as having lymphocytic interstitial pneumonitis). Four of the LIP group developed bronchiectasis, a finding not previously reported. The precise factors leading to the bronchiectasis are unclear. All patients had chronically consolidated lung with volume loss. A history of recurrent bacterial superinfection was not noted in any of the cases. With more cases of HIV positive children living longer, bronchiectasis, long known to occur in primary immunologic disorders, will probably be more frequently noted.

Acquired Immunodeficiency Syndrome

A simple CT aperture emulator for use with a radiotherapy simulator.

Tumor localization in radiation treatment planning often involves the generation of quantitative anatomical data from multiple imaging modalities. It is desirable to take all of the images in the selected treatment position, which is usually decided upon during the initial simulator session. The different scanning modalities are often operated by different staff, at different times and in different locations; thus, it is difficult to ensure consistency in the position of the patient's body, and its documentation, at various times and places. Also, devices such as CT and MR scanners frequently pose restrictions due to their limited apertures. Failure to consider the physical limitations of such scanning equipment at the time of simulation or localization may result in placing the patient in a treatment position which will not fit through the aperture of the CT (or MRI) scanner, or which will result in a clinically important portion of the anatomy being "cut off" in the resulting scans. This can lead to re-simulation of the patient or result in a lack of accurate coordination of simulator and CT scan data. To minimize problems such as these, we have developed a CT Aperture Emulator which can be used at the time of the initial simulation. This is a lightweight "halo" easily attached to the simulator, which mimics the size and shape of the CT aperture. It permits reproducible adjustment of the patient's position, while allowing technologists and physicians to set up the patient with respect to potential CT constraints, in particular with regard to the use of immobilization and support devices. The emulator device also facilitates reproducing a patient's treatment position on the CT scanner. The concept has been found to have additional clinical uses and can be extended to a variety of imaging equipment.

Posture

A Hox 3.3-lacZ transgene expressed in developing limbs.

We describe transgenic mouse lines that express lacZ under the control of the Hox 3.3 Promoter II. The correct anterior boundary can be fixed by 3.6 kb of promoter DNA (plus 1.6 kb of 5' transcribed sequences), both in tissues of ectodermal and mesodermal origin. The posterior border, however, is not respected, and lacZ expression continues into the tail region. One line has particularly strong graded expression in the anterior proximal limb bud. Other lines, containing a shorter promoter fragment (0.6 kb), have ectopic expression in the head region, including one line that has expression in the anterior half of the retina. Such mouse lines make it possible to molecularly distinguish cells in regions of the embryo that look otherwise identical and may be useful in studying the establishment of molecular differences in the mouse embryo.

Animals

A simple method for indirectly verifying noncoplanar treatment fields in radiotherapy.

The use of a vertex field can be a practical technique for treatment of pituitary and brain tumors. This approach may be underutilized, primarily because of the difficulty in documenting noncoplanar treatment fields. This paper describes a method for documenting vertex treatment fields by inference using portal films. This method is relatively simple to implement, yet yields accurate results.

Brain Neoplasms

Susceptibility and behavioral response of red imported fire ant (Hymenoptera: Formicidae) to selected entomogenous nematodes (Rhabditida: Steinernematidae & Heterorhabditidae).

Pathogenicity of infective juveniles of selected Steinernema spp. and Heterorhabditis spp. toward developing and reproductive stages of the red imported fire ant, Solenopsis invicta Buren, was tested under laboratory conditions. At 10(3)-10(5) infective juveniles per Petri dish, mortality of reproductive larvae, pupae, and alates ranged from 28 to 100% at higher doses after 96 h at 23-25 degrees C. Steinernema carpocapsae All was the most consistent species tested; this nematode caused mortality of fire ant larvae, pupae, and alates of 82-94, 64-96, and 38-99%, respectively. Although not susceptible to nematode infection, worker ants vigorously preened nematodes from brood, alates, and themselves. In a field study, S. carpocapsae (5 x 10(6) and 2 x 10(6) drench, 2 x 10(6) infective juvenile infection) was applied to active fire ant mounds in 3.8-liter suspensions. Hydramethylnon (75 ml), a water drench, a water injection, and untreated fire ant mounds were marked and treated. Overall activity in mounds treated with nematodes of hydramethylnon ranged from 40 to 48%. Satellite mound activity accounted for 32-44% of overall activity in mounds treated with nematodes 2 wk after treatment. However, 6 wk after treatment, activity in mounds treated with hydramethylnon was 44%; activity of mounds treated with nematodes ranged from 52 to 80%. Satellite mound activity accounted for 0-24% of overall activity. Whereas a soil drench of S. carpocapsae showed potential as a control method for the red imported fire ant, colony relocation after nematode treatment could limit overall efficacy unless application techniques are developed to overcome or take advantage of the movement.

Animals

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

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

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

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