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Biomedical subjects

R G Rossing

Publications and source records attributed to R G Rossing.

At least 19 recordsLinked to original sources
PubMed1985

Comparison of sequential anterior and posterior rhinomanometry.

This study was conducted to test the validity in adult subjects of the commonly used technique of summing anterior nasal measurements to describe the patency of the total nose. We measured the total nasal conductance in 36 nonallergic, nonsmoking subjects by use of posterior rhinomanometry (PRM) and compared the results with sequential summed unilateral conductances in the same subjects based on anterior rhinomanometry (ARM). Linear regression of the relationship between the two measures demonstrated significant differences. Variation between these two measures is composed of two parts: random time variation and a component attributable to the difference between methods. Random time variation was estimated from five serial posterior nasal conductances in nine of the subjects in a second experiment. We observed significantly greater variations between ARM and PRM than between PRM measures separated by similar time intervals (F 36.36 = 2.30, p less than 0.01). We conclude that PRM is significantly more accurate than summed ARM when the goal is to quantitate precisely the patency of the nose as a whole at a given instant in time, and yet summed ARM measurements may be acceptable in clinical studies wherein large changes in nasal patency occur.

Adolescent↗
PubMed1985

Tests for departure from normal in laboratory data.

This study was undertaken to compare several methods of evaluating the common assumption that laboratory data may be treated as if they had been drawn from an underlying Gaussian distribution. As had been described earlier, the usual Kolmogorov-Smirnov test was found to be unsatisfactory due to its sensitivity to rounding. In addition, a recently suggested modification also was shown to be unsuitable, because it was quite insensitive when applied to simulated data known to be positively skewed. The authors suggest the following: that the coefficients of kurtosis and skewness are valuable for use against specified alternatives; that the traditional Kolmogorov-Smirnov test is appropriate if the degree of rounding is minimal; and that a satisfactory "omnibus" test is not yet available.

Blood Chemical Analysis↗
PubMed1982

Survival in lung cancer. An analysis of the effects of age, sex, resectability, and histopathologic type.

Records of 6,686 patients with primary lung malignancies were retrieved from a tumor registry. Survival curves according to histopathologic type demonstrated that patients with anaplastic tumors have a lower cumulative survival than those with either squamous cell cancers or adenocarcinomas (p less than 0.001), but survival for the latter two histologic types is similar. Age at diagnosis influences survival, and women with squamous or anaplastic tumors have a better prognosis than men with the same cell types (p less than 0.001). Although selection for resection is strongly associated with lower early mortality, all patients alive 2 yr after diagnosis have a similar prognosis is regardless of initial resectability. Each survival curve shows a high early mortality and a lower late mortality, indicating that each group can be considered to consist of 2 subgroups with different risks of dying of lung cancer. A mathematical model is described that closely approximates the actuarial survival.

Adenocarcinoma↗
PubMed1980

The stability of clinical chemistry specimens during refrigerated storage for 24 hours.

The authors investigated the stability of the tests comprising the SMA-6 and SMA-12 chemistry profiles during overnight refrigerated storage. Several constituents were found to undergo changes that were statistically significant when evaluated by a t test for paired comparisons. A recently published sequential method for judging sample stability was found to be somewhat less sensitive than the traditional statistical procedure. Only one determined value (CO2) underwent a change that was judged to be of medical significance. Two previously published criteria were used for this evaluation, one based on clinical judgment and the other on biologic variation. Variability of the results of repeat determination did not appear to be increased by overnight storage.

Blood Chemical Analysis↗
PubMed1980

Hematology reference values. Analysis by different statistical technics and variations with age and sex.

The following hematologic parameters in 1,744 healthy men and women aged 16 to 89 years were studied: leukocyte count, erythrocyte count, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration. The frequency distributions of all parameters were statistically significantly deviated from Gaussian distributions. Standard Gaussian statistical methods as well as nonparametric methods were used to establish 95% reference intervals for each parameter. The effects of sex and age upon these parameters were also studied. Significant age differences, which were most striking for leukocyte count, erythrocyte count, MCV, and MCH, were detected.

Adolescent↗
PubMed1979

A computer program for estimation of reference percentile values in laboratory data.

It has been suggested that the physician would be aided in his interpretation of clinical laboratory results if the data were reported in terms of percentile ranking in a reference population as well as in conventional units. This paper describes a FORTRAN porgram for estimating the necessary reference percentile values by means of regression over 20% of the distribution rather than by interpolation between adjacent points. The regression estimates are shown to have a negligible bias and to be somewhat more stable than those obtained by interpolation.

Clinical Laboratory Techniques↗
PubMed1979

Percentiles as reference values for laboratory data.

It has been suggested that laboratory results be reported, not only in conventional units, but also in terms of equivalent percentiles from a reference population. This would afford the clinician an easily interpretable measure of how unusual such a result would be in the reference population. This paper describes a modified method for estimation of reference percentiles. This method does not require any assumption about the distribution of the reference population, but it has a smaller variability than that from earlier methods based on interpolation. This method is now being used to furnish percentile values for spirometric data in the authors' laboratory.

Clinical Laboratory Techniques↗