PubMed Health⌕ Search

Biomedical subjects

H D Maillie

Publications and source records attributed to H D Maillie.

At least 19 recordsLinked to original sources
PubMed1995

A test of the hypothesis that cavitation at the focal area of an extracorporeal shock wave lithotripter produces far ultraviolet and soft x-ray emissions.

Church hypothesized that the violent collapse of microbubbles in water in the focal area of an extra-corporeal shock wave lithotripter (ESWL) can generate biologically damaging far uv and soft x-ray photons. Two techniques were used to test this hypothesis. Gassy water (10 ml) was exposed to ten piezoelectric lithotripter shocks (P+ = 43 MPa, P- = 9 MPa). The resultant sonoluminescence was filtered by optical band-pass filters and measured using a photomultiplier tube (PMT). Next, a commercially available scintillation cocktail (Ecoscint A), which is formulated to convert high energy photons to visible light, was exposed to varying numbers of lithotripter shocks and the relative luminescence intensity measured and compared to background and distilled water luminescence readings. Results showed support for the hypothesized presence of near uv emissions (approximately 250 nm) and marginal support for the production of higher energy photons, possibly including far uv and soft x-ray emissions.

Equipment Design↗
PubMed1994

The influence of life table corrections for smokers and nonsmokers on the health effects of radon using the BEIR (biological effects of ioniziing radiation) IV method.

The BEIR IV report gives graphs and tables that are used to estimate the risks due to radon (222Rn) and its decay products. The BEIR IV hypothesis predicts that the lifetime risks will depend upon the "normal" incidence of fatal lung cancers for nonsmokers and smokers and the life expectancies of both groups. This paper examines the influence of recent information on these health risks. The factors considered are a) the life tables for both sexes and for those who never smoked, formerly smoked, are currently light smokers, or are currently heavy smokers, and b) the age-dependent fatal lung cancer rates for the same groups of people. In general, the calculations indicate that people who have never smoked would have the same risks as those listed in the BEIR IV report as nonsmokers. For males, those who smoke or formerly smoked would have calculated risks that are greater than people who never smoked; however, for males, the smokers and former smokers considered in this paper have lower calculated risks than the BEIR IV smokers. For females, the heavy smokers examined here would have greater calculated risks than the BEIR IV smokers. The reasons for these differences are presented.

Female↗
PubMed1993

Radiation-induced cancer risk in radiographic cephalometry.

The carcinogenic risks associated with the cephalometric x-ray techniques customarily used in orthodontics and oral surgery have been estimated. Lateral, posteroanterior, 45 degrees oblique, lateral temporomandibular joint tomography, basilar techniques, and commonly-used combinations were examined. Data reported in a previous article on doses absorbed by pituitary (brain), salivary, and thyroid glands were used to calculate increased risk over normal incidence using the BEIR V model. The findings are expressed in a number of graphs. Tables list the estimated percentage increase in carcinomas for several of the most often used cephalometric procedures, and compare these with the more common complete mouth (periapical) and panoramic surveys. The overall conclusion is that responsible use of cephalometric radiology adds very little to the person's carcinogenic burden.

Absorption↗
PubMed1993

Determining person-years of life lost using the BEIR V method.

A method is given that permits the calculation of the estimated person-years of life lost when groups of males or females are exposed to low linear energy transfer (LET) ionizing radiation. It is felt that this determination is informative in rating risks to populations from radiation exposures. For example, when 1,000,000 females have received an acute 10 mSv, the total number of radiation-induced fatal cancers is 835. The total number of person-years of life lost is 1.4 x 10(4) or an average of about 5 d. However, the 22 who die of leukemia suffer an average of about 34 y. Those who die of other forms of cancer lose an average of 16 y. Some examples have been reported by the U.S. National Academy of Sciences (1990) report. In those cases where the Committee presented results, the method given here is in good agreement.

Age Factors↗
PubMed1992

Dosimetry of absorbed radiation in radiographic cephalometry.

Absorbed radiation was measured in various craniofacial tissues on an adult phantom (Alderson Rando) when conventional cephalometric radiographic techniques were used. The views examined were lateral, 45 degrees oblique, posteroanterior, lateral temporomandibular joint tomograph, and basilar (submental-vertex). Absorbed radiation was expressed in micrograys for the individual views and for combinations of views as customarily used in orthodontics and oral surgery. These data are compared with findings of contemporary investigators and the magnitude of the doses is compared with those in the literature for periapical and panoramic surveys.

Absorption↗
PubMed1992

Age related rejoining of broken chromosomes in human leukocytes following X-irradiation.

One theory of aging is that the ability to repair DNA or chromosome damage decreases with age. This study made use of a method which allows the measurement of chromatid repair in interphase nuclei, the technique of premature chromosome condensation. The number of excess chromosome fragments per cell remaining after 24 h of incubation at 37 degrees C was determined and used as a measure of the ability of leukocytes to repair. The leukocytes from male donors of several ages were used and the cells from older donors showed greater residual damage and, therefore, less repair.

Adolescent↗
PubMed1992

A graphical method of estimating fatal radiation-induced cancers using the BEIR V method.

A method is presented that permits health physicists to estimate the risks of radiation-induced cancers in populations of males or females exposed to whole-body external irradiation at any age. Graphics are presented that may be used for either acute or chronic exposures. There is good agreement for chronic exposures when the cancer estimates determined here are compared with those prescribed in BEIR V. There are differences between the two when considering some acute exposures. In such circumstances, the method given here generally gives conservative results.

Environmental Exposure↗
PubMed1992

A means of retaining chromosome damage in irradiated human lymphocytes.

The method of premature chromosome condensation has been used to determine the damage induced by ionizing radiation to chromosomes in G1 human lymphocytes. The method has also demonstrated the repair of such damage with time following exposure. This study shows how storage at a cold temperature can be used to retain this damage for further biodosimetric study.

Animals↗
PubMed1989

A graphical method to determine the uptake of nuclides by workers.

A method is presented which simplifies the estimation of the uptake, retention, and elimination of radioactive or stable nuclides following instantaneous ingestion or inhalation. A graph can be presented which shows the time-related presence of the element in organs of interest. It is not necessary to go back to the original differential equations used in the metabolic models or to resort to the publications which present their solutions. A glance at a graph and some simple calculations will allow the health professional to make the required determinations.

Aerosols↗
PubMed1985

Direct analysis of radiation-induced chromosome fragments and rings in unstimulated human peripheral blood lymphocytes by means of the premature chromosome condensation technique.

Development of the procedure to stimulate peripheral blood lymphocytes has greatly facilitated the understanding of chromosome aberration formation and repair mechanisms in human cells. Yet, because radiation induces far more initial chromosome breaks than are observed as aberrations in metaphase, it has not been possible to examine the kinetics of primary chromosome breakage and rejoining with this procedure. An improved method to induce premature chromosome condensation in unstimulated lymphocytes has been used to study primary chromosome breakage, rejoining, and ring formation at various times after irradiation with up to 800 rad of X-rays. The dose-response relations for chromosome fragments analyzed immediately or 1, 2, or 24 h after exposure were found to be linear. Rapid rejoining of chromosome fragments, which takes place in the first 3 h after X-ray exposure, was not correlated with a simultaneous increase in the formation of rings. The yield of rings per cell scored 24 h after irradiation, however, increased significantly and fit a linear quadratic equation. Both chromosome fragment rejoining and ring formation were completed about 6 h after irradiation. The frequency distributions of rings among cells followed a Poisson distribution, whereas chromosome fragments were overdispersed.

Animals↗
PubMed1985

The measurement of immediate and persistent radiation-induced chromosome damage in rodent primary cells using premature chromosome condensation.

The chromosome damage observed in cultured peripheral blood lymphocytes at their metaphase is considered to be the most reliable basis for biological dosimetry. However, physical and biological factors such as irradiation conditions and chromosome repair could make difficult the interpretation of chromosome aberration yield in terms of absorbed dose. To establish correction factors to take into account partial body exposure, dose rate, and post-irradiation time requires in-vivo studies. Yet, such studies may be hampered by the laborious techniques required to culture the blood of the more readily available laboratory animals. In this paper, a cytogenetic approach based on a simple method for polyethylene-glycol-mediated cell fusion and premature chromosome condensation induction in primary cells is shown to be useful for in-vivo studies involving rodents. This method enables the direct assessment of radiation-induced chromosome damage without having the cells proceed to mitosis. The applicability of the method is demonstrated in particular for the measurement of immediate and persistent radiation-induced chromosome damage in rat peripheral blood, spleen, and thymus lymphocytes.

Animals↗
PubMed1985

A method of estimating the risks from ingested radionuclides.

A technique is presented for estimating the number of radiation-induced cancers in organs exposed following the ingestion of radionuclides. The method takes into account the dose rate, the sex and the age of the individuals exposed. It assumes a linear no-threshold response and does not incorporate biological repair mechanisms. Two examples are presented which demonstrate that although the dose-equivalent limits may be the same, the different dose rates involved result in different risks.

Actuarial Analysis↗
PubMed1984

The calculation of total transformations in organs following the inhalation of radioactive aerosols of different sizes.

A technique is presented which makes use of the ICRP methodology for calculating the total number of transformations in an organ following the inhalation of radioactive aerosols of various half-lives and activity median aerodynamic diameters (AMADs). As found in studies involving respiratory and gastrointestinal tract activities under similar conditions, there are constants common to the aerosol class which allow the plotting of factors which depend only upon the radioactive half-life of the isotopes involved. The method shows the influence of respiratory uptake on the total number of transformations in the organ as well as the influence of AMAD and the route the isotope takes to the organ, e.g. directly from the respiratory tract or via the gastrointestinal tract. Although the technique is more complicated than that used for the respiratory or gastrointestinal tract uptake, the method requires a minimum of calculation.

Aerosols↗
PubMed1984

Tritium distribution and excretion following intratracheal instillation of glass microballoon fragments in rats.

The distribution and time course for tritium activity in Sprague-Dawley rats exposed to tritiated glass fragments by intratracheal instillation have been defined. Particles were deposited primarily in the pulmonary region, allowing for the measurement of long-term tritium dissolution and particle movement. The tritium activity of the body water and tissues was found to follow a three-compartment model where tritiated glass fragments provide a continuous input to the body water, and tritium was removed from the body according to the classical elimination pattern for HTO. The dissolution of tritium in vivo was found to be biphasic with exponential function half-times of 6.3 +/- 0.5 and 43 +/- 3 days, respectively. The glass fragments were removed from the pulmonary region slowly, with a half-time of 150 +/- 30 days. The resultant dose to the lung was three orders of magnitude greater than the dose to the body, and approx. 40 times greater than the dose incurred in the lung from the inhalation of a similar quantity of HTO. A theoretical urine tritium time course for the inhalation of glass fragments was found to resemble the typical HTO patterns for several months post-exposure. The similarity of tritiated glass and HTO urine activity will make the determination of the type of exposure difficult.

Accidents, Occupational↗
PubMed1984

Limited life-table factors for estimating radiation-induced cancers over finite time periods.

A method is presented that allows the estimation of radiation-induced cancer incidence or mortality at varying times post-exposure in irradiated populations of males or females of ages ranging from 10 to 70 yr. Limited life-table factors are given in graphic form for 2 sets of conditions: when the latent period is 2 yr and the plateau 30 yr and when the latent period is 10 yr and the plateau extends to the end of life. Normal incidences for selected forms of cancer are also presented. Examples are given that show how to calculate the radiation excess cancers and to compare this excess with the normal. The implications of these numbers are also discussed.

Actuarial Analysis↗