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M Espeland

Publications and source records attributed to M Espeland.

22 records · Page 2Linked to original sources

Estimation of growth curves from longitudinal data collected at irregular time intervals.

A general procedure for fitting growth curves is proposed that can be applied to longitudinal data even if observations are missing or irregularly spaced. Maximum likelihood estimates for mean growths are obtained from an EM algorithm. Estimates for standard errors, percentiles, and growth velocities are also produced. The techniques are demonstrated through the use of growth data from a longitudinal study of sickle cell disease.

Algorithms↗

Interproximal gingival inflammation related to the conversion of a bleeding to a nonbleeding state.

Elimination of gingival bleeding has been related to a reduction in inflammation; however, histologic data are not available to support this association. The purpose of this study was to characterize the histology of interproximal gingiva that was converted from a bleeding to a nonbleeding state. An interproximal gingival biopsy was obtained from each of 32 patients, 15 of whom bled upon stimulation with a soft wooden interdental cleaner. The remaining 17 biopsies were obtained from sites which initially bled, but were converted to nonbleeding by scaling and interproximal plaque control. Specimens were processed for light microscopic evaluation and subjected to a morphometric analysis for various tissue components. Data from bleeding and "stopped bleeding" specimens were compared using analysis of covariance. The results indicated that "stopped bleeding" specimens had significantly less inflamed connective tissue. It was concluded that the conversion of a bleeding to a nonbleeding state corresponds with a histological reduction in the magnitude of the interproximal inflammatory lesion and provides a rationale, therefore, for the use of bleeding to monitor the effects of therapeutic methods.

Adult↗

Developmental pattern of splenic dysfunction in sickle cell disorders.

Splenic function in sickle hemoglobinopathy syndromes was assessed to determine the developmental pattern of splenic dysfunction. Nonvisualization of the spleen using technetium-99 metastable (99mTc) spleen scans correlated strongly with pocked (vesiculated) RBCs greater than or equal to 3.5%. Cross-sectional analysis of pocked RBC data from 2,086 patients showed differences in the developmental pattern of splenic dysfunction between several disorders. In hemoglobin SS disease (sickle cell anemia) and hemoglobin S beta(0) thalassemia, splenic dysfunction (greater than or equal to 3.5% pocked RBCs) often occurred in the first 6 to 12 months of life. In hemoglobin S beta(+) thalassemia, splenic dysfunction occurred less frequently and later. Splenic dysfunction in hemoglobin SC disease (sickle cell-hemoglobin C) was intermediate. The level of pocked RBCs was inversely associated with fetal hemoglobin (P less than .007) and directly associated with age (P less than or equal to .001). These patterns of splenic dysfunction reflect the known severity of hemolysis and intravascular sickling and are consistent with the epidemiology of severe bacterial meningitis and sepsis in these diseases. Serial measurement of pocked RBCs permits determination of the onset of splenic dysfunction and the time of increased susceptibility to severe bacterial infections.

Age Factors↗