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B Bunnag

Publications and source records attributed to B Bunnag.

14 recordsLinked to original sources
PubMed1987

Comparing new and old screening tests when a reference procedure cannot be performed on all screenees. Example of automated cytometry for early detection of cervical cancer.

Direct determination of the sensitivity and specificity of a screening test requires use of a reference procedure (such as biopsy with histopathologic analysis) that provides an estimate of true disease status. The authors present a method for comparing the accuracy of a new screening test to an old one in situations when it is not feasible to apply the reference procedure to all screenees. This method requires that only those persons who test positive on old or new screening tests be further evaluated with the reference procedure. Ratios of sensitivities and specificities are derived for rapid comparison of the two screening tests. It is shown that McNemar's test can be used for significance testing of the differences in sensitivities and specificities between two screening tests. The required sample size for a study that compares the two tests is determined.

Female↗
PubMed1983

Ultrastructural investigations on the effects of praziquantel on human trematodes from Asia: Clonorchis sinensis, Metagonimus yokogawai, Opisthorchis viverrini, Paragonimus westermani and Schistosoma japonicum.

The effect of praziquantel (Biltricide) on the ultrastructure of trematodes pathogenic to man in Asia was investigated in: Clonorchis sinensis, Opisthorchis viverrini, Schistosoma japonicum, Metagonimus yokogawai, and Paragonimus westermani. The different parasites were isolated from their respective experimental hosts and uniformly incubated for 5, 15, 30 or 60 min at 37 degrees C in medium TC 199 containing 0, 1, 10 or 100 micrograms praziquantel/ml. All parasites exposed to praziquantel were contracted and displayed tegumental alterations. 1. Clonorchis sinensis, Opisthorchis viverrini and Schistosoma japonicum reacted with severe tegumental vacuolisation within 5 min after exposure to 1 microgram praziquantel/ml. The extent of the damage induced increased with exposure time. 2. In vivo treated Opisthorchis viverrini worms had the same damages as in vitro treated ones. 3. Metagonimus yokogawai displayed the same degree of vacuolisation after exposure to all concentrations of praziquantel. Complete destruction of the tegumental surface was not achieved, however, possibly because of the presence of numerous tegumental hooks. 4. Paragonimus westermani was least sensitive to praziquantel. Only very few vacuoles were formed after incubation in 100 micrograms/ml for 60 min. It is assumed that the very dense texture of the thick tegument is responsible for the relative refractoriness to praziquantel in vitro. However, in vivo the parasite is successfully eliminated by praziquantel.

Animals↗
PubMed1979

Quantitative analysis of flow microfluorometric data for screening gynecologic cytology specimens.

Gynecologic cytology specimens that included the entire spectrum of cervical cytology classification were stained with a combination of propidium iodide and fluorescein isothiocyanate, then analyzed using a flow microfluorometer to measure nucleic acid and protein content, respectively. Numerous descriptors of the resulting two parameter distribution (nucleic acid versus protein) were defined. These descriptors included assessment of the presence or absence of abnormal cells. They also included measures of the staining intensity and dispersion of the normal squamous cell population and the intensity of inflammatory response in the cell population. Relative percentages of inflammatory and epithelial cells were demonstrated to effect the screening performance of this system only in borderline lesions. Decision tree algorithms allowed optimization of the selected parameters for screening logic of normal-abnormal decisions on a specimen-by-specimen basis. In addition, quantitative definitions of specimen adequacy were determined. Appropriate controls for batch staining of specimens were evaluated. These results of applying pattern recognition techniques to flow microfluorometer multiparameter data demonstrate that considerably more information about cell populations and subpopulations can be extracted than heretofore possible.

Adolescent↗
PubMed1976

Goals of the cytology automation program of the National Cancer Institute.

The immediate goal of the Cytology Automation Program of the National Cancer Institute is the development of an automated system which will screen appropriate specimens from asymptomatic women for squamous cell carcinoma of the cervix and its precursor lesions, dysplasia and carcinoma in situ. This system should make one of three decisions on each specimen: normal, abnormal or inadequate with an acceptably low false negative rate. It is expected that the next step in evaluation of patients whose specimens have been identified as abnormal by the automated system would be a manual evaluation of a traditional cytologic specimen.

Autoanalysis↗
PubMed1976

Flow microfluorimetric analysis of sensitive and resistant leukemia L1210 following 1-beta-D-arabinofuranosylcytosine in vivo.

Two groups of BALB/c X DBA/S F1 mice with sensitive and 1-beta-D-arabinofuranosylcytosine-resistant L1210 ascites, respectively, were used to study the cytokinetic effects of a single dose of 750 mg of 1-beta-D-arabinofuranosylcytosine per kg. Sequential DNA histograms, labeling indices, and mitotic indices were obtained from each of five mice at timed intervals from 0 to 72 hr. Each histogram was obtained by flow microfluorimetry, using the DNA-specific fluorochrome, mithramycin. The histograms were then integrated for cell cycle analysis. Cytokinetic perturbations occurred in both groups, but they were greater in the sensitive population where there was a relative accumulation of cells, mainly in early S phase, at 16 hr. This was followed by a relative depletion of S-phase cells. In the resistant population, there were relative accumulation of cells in early S phase at 8 and 24 hr and in mid-S phase at 32 hr, but there was no subsequent relative depletion of S-phase cells. The labeling index was rapidly reduced in both groups but was recovered in the resistant population within 4 hr. In the sensitive population, there was a transient rise in the labeling index at 8 and 16 hr. Sensitive and resistant populations of L1210 cells were rapidly and reliably distinguished by DNA content cell cycle analysis of a single sample taken between 24 and 72 hr following a large dose of 1-beta-D-arabinofuranosylcytosine. This technique has potential clinical application in the rational design and monitoring of chemotherapy.

Animals↗