Improved clearance verification.

This paper describes clearance as the sum of fractions (SOF) inequality with acceptable probability. We include scenario modelling uncertainties in SOF calculations. An illustrative contrast of results with and without the modelling uncertainties shows the differences in the probabilities that the standards were met.

Action levels for airborne uranium in the workplace: chemical and radiological assessments.

A method is described for deriving two levels of action-an investigation level (IL) and an immediate action level (IAL)-for different forms and mixtures of the natural uranium (U) isotopes U, U, and U in air in the workplace. An IL indicates the need to confirm the validity of moderately elevated measurements of airborne U and adequacy of confinement controls and determine whether work limitations are appropriate. An IAL indicates that safeguards should be put into place immediately, including removal of workers from further exposure until conditions are acceptable.

Complete decay of radionuclides: implications for low-level waste disposal in municipal landfills.

The time required for the complete decay of a radioactive source can be quantified by specifying an acceptable probability and using an original derivation. The physical phenomenon of complete decay may be used as the technical basis to change regulations and permit, with public acceptance, the inexpensive disposal of short half-lived radioactive waste into municipal landfills. Current regulations require isolation of trash from the biosphere for 30 years during the post-closure control period for municipal landfills.

Continuous versus bilevel positive airway pressure for obstructive sleep apnea.

Recent objective studies demonstrate relatively low hours of nightly use during nasal continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea (OSA). Patients frequently complain of dyspnea or discomfort during CPAP use, especially during expiration (against the continuous pressure), which may be a reason for the low hours of use. We hypothesized that with decreased expiratory pressure, hours of nightly use would increase.

Nasal CPAP: an objective evaluation of patient compliance.

Nasal continuous positive airway pressure (NCPAP) improves sleepiness and prognosis in obstructive sleep apnea (OSA). Our objective was to document NCPAP compliance and the percentage of time that the effective pressure shown to eliminate 95% of the obstructive apneas and hypopneas was maintained. We built and covertly installed an elapsed timer and mask pressure transducer recorder in NCPAP units of 47 OSA patients.

Criteria for the administration of KI for thyroid blocking of radioiodine.

Scientific data are reviewed to evaluate the risks of radioiodine uptake and to compare those risks with the benefits and risks of low milligram doses of stable potassium iodide (KI). The limit of 25 rad to the thyroid due to radioiodine uptake is adopted as the "break-even" point above which 130-mg KI doses should be administered. The biological and radiological kinetics of radioiodine for protracted uptakes were derived from the Medical Internal Radiation Dose Committee (MIRD) model (MIRD75).

Inhibition of cell cycle progression of human pancreatic carcinoma cells in vitro by L-(alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid, Acivicin (NSC 163501).

The inhibition of cell cycle progression of a human pancreatic carcinoma line, MiaPaCa-2, by L-(alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (Acividin), an antimetabolite and glutamine antagonist, was investigated by means of flow cytometry, cell cycle kinetics, and cell enumeration. Flow cytometric criteria for logarithmically growing MiaPaCa-2 cells were established. Logarithmically growing cells exposed to 50 microM Acivicin appeared to markedly reduce their rate of cell cycle progression after they passed a point in later G1 phase or in early S phase.

Establishment and cell cycle kinetics of a human squamous cell carcinoma in nude mice and in vitro.

A human squamous cell carcinoma of the virus was xenografted to athymic, nude mice. A tissue culture cell line designated SqCaVu-1H was derived from a second-passage xenograft. The growth characteristics and cell cycle kinetics in the xenografts and in SqCaVu-1H cells were compared.

Collodion membrane secures cells sorted by flow cytofluorometry onto microscope slides.

Quantitative microscopic cytology of cells previously sorted by flow cytofluorometry has been hindered by the loss of cells from the microscope slide during staining procedures. The simple application of a semi-permeable membrane of collodion over fixed or unfixed cells sorted directly onto a microscope slide secured virtually 100% of the cells onto the slide. Cells covered with the collodion membrane studied with Papanicolaou's stain as well as routine clinical cervical cytologic preparations.

The inhibition of gamma-glutamyl transpeptidase from human pancreatic carcinoma cells by (alpha S,5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (AT-125; NSC-163501).

AT-125, (alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid, at a concentration of 5 microM was found to inhibit the growth of human pancreatic carcinoma cells (MIA PaCa-2) by 78% after 72 hours in continuous culture. It was found that MIA PaCa-2 gamma-glutamyl transpeptidase (10 nmol/min/10(6) cells) was irreversibly inactivated by AT-125 with an inactivation half-life of 80 minutes at 450 microM.

Predominance of granulocytopoiesis in bone marrow grafts in the omenta of mice treated with erythropoietin.

The effects of erythropoietin on the differentiation of murine bone marrow injected into the omenta of x-irradiated mice were investigated. Experimental hosts were injected with 2.5 units of erythropoietin on days 0-7 and sacrificed on day 10.

Interkingdom fusion between human (HeLa) cells and tobacco hybrid (GGLL) protoplasts.

The fusion of human HeLa cells with tobacco protoplasts has been accomplished with the use of polyethylene glycol. The sequence from heterocellular adherence to heterokaryon formation has been followed with light microscopy and confirmed by autoradiographs of heterokaryons containing unlabeled tobacco nuclei and tritium-labeled HeLa nuclei. The HeLa nucleus retained its integrity in the tobacco cytoplasm up to 6 days after fusion.

Growth of HeLa cells in diffusion chamber cultures in vivo.

In order to investigate some characteristics of Millipore diffusion chamber cultures (DCC) and their potential for the quantitation of tumor cell growth kinetics, HeLa S-3-cells were grown in diffusion chambers implanted i.p. in mice.