Biomedical subjects

D Carl Freeman

Publications and source records attributed to D Carl Freeman.

7 recordsLinked to original sources

PubMed2006

Surgical correction of dorsally angulated distal radius malunions with fixed angle volar plating: a case series.

PURPOSE: To report our experience using a fixed-angle volar plate in conjunction with a corrective osteotomy and cancellous bone graft for the treatment of distal radius malunions with dorsal angulation in 4 patients. METHODS: Four consecutive patients had a volarly based opening wedge osteotomy with a fixed angle volar plate and cancellous bone grafting for the treatment of a dorsally angulated distal radius malunion. Data collected retrospectively included a visual analog pain scale, grip strength, range of motion, radiographic parameters, and each patient's subjective functional outcomes as measured by the Disabilities of the Arm, Shoulder, and Hand questionnaire. Motion, strength, and radiographic values were compared with the contralateral arm for each patient. RESULTS: The average time from initial fracture to corrective osteotomy was 346 days. The average length of follow-up evaluation was 13.5 months. The flexion-extension arc of motion increased an average of 21 degrees to a value of 84% of the contralateral side; the pronation-supination arc of motion increased an average of 20 degrees to a value of 98% of the contralateral side. The average tilt of the radius improved from 26 degrees extension to 2 degrees extension; the average radial inclination improved from 22 degrees to 24 degrees; the average ulnar variance excluding the 1 patient who had a distal ulna resection improved from 5 mm to 1 mm. The average retrospective Disabilities of the Arm, Shoulder, and Hand score improved from 30 to 7; the average retrospective visual analog pain scale score improved from 4.5 to 1. The average grip strength increased from 20 to 29 kg, which corresponded to 73% of the contralateral extremity. CONCLUSIONS: The rigid characteristics of fixed angle volar plates can provide an alternative to the traditional techniques of distal radius osteotomy including structural bone grafting and dorsal plate fixation or external fixation. In addition these plates are strong enough to allow for early postoperative motion. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adolescent↗

PubMed2004

Habitat disturbance and the diversity and abundance of ants (Formicidae) in the Southeastern Fall-Line Sandhills.

We examined habitat disturbance, species richness, equitability, and abundance of ants in the Fall-Line Sandhills, at Fort Benning, Georgia. We collected ants with pitfall traps, sweep nets, and by searching tree trunks. Disturbed areas were used for military training; tracked and wheeled vehicles damaged vegetation and soils. Highly disturbed sites had fewer trees, diminished ground cover, warmer soils in the summer, and more compacted soils with a shallower A-horizon. We collected 48 species of ants, in 23 genera (141,468 individuals), over four years of sampling. Highly disturbed areas had fewer species, and greater numbers of ants than did moderately or lightly disturbed areas. The ant communities in disturbed areas were also less equitable, and were dominated by Dorymyrmex smithi.

Animals↗

PubMed2004

Shoulder outcome measures: a comparison of 6 functional tests.

BACKGROUND: Several shoulder function scores are used in research, with no universally adopted standard. This study compares 6 shoulder outcome scales. HYPOTHESIS: Correlations exist between shoulder outcome scales, allowing conversion between scales. Shoulder scales are correlated with age. STUDY DESIGN: Regression and correlation study. METHODS: Seventy subjects with shoulder pain completed 6 shoulder outcome scales. Pearson correlations were calculated between the total scores of the 6 instruments, between the components of the scales, and with age. Regression equations were calculated between scales. RESULTS: The range of r values for total scores was 0.495 < or = r < or = 0.770, P < or = .01. In general, a scale's components were themselves highly correlated and added little new information to the scale (0.260 < or = r < or = 0.705, P < or = .05). Most of the scale scores were highly correlated with age (0.291 < or = r < or = 0.582, P < or = .05). Constant's reported corrections for age reduced (from r = -0.582 to r = -0.250, P < .05) but did not eliminate age as a confounding variable. CONCLUSIONS: Correlations exist between shoulder outcome scales, but existing shoulder scales are not equivalent in their assessments of function; they contain redundant information and, in some cases, may reflect a patient's age better than his/her shoulder function. The utility of conversion equations is minimized as a result of low to moderate correlations between scales.

Female↗

PubMed2004

Predicting shoulder strength using allometry: implications for shoulder outcome assessments.

INTRODUCTION: Shoulder strength is an integral component of shoulder function. In assessing shoulder function many functional scales rely on direct or indirect measures of strength. Strength, and thus these scales, is often highly correlated with age. We propose an allometric method for assessing shoulder strength. Allometric modeling has provided accurate predictions of biologic growth and physiologic function in both human and animal studies. Allometry utilizes the relationship between the two homologous structures on the left and right sides of the body, providing in effect an internal control and thus eliminating many confounding effects, e.g. age and level of activity. METHODS: Twenty patients with unilateral shoulder dysfunction underwent strength testing of their affected and unaffected shoulder. Strength testing of the bilateral shoulders was also assessed in twenty people without shoulder pain in order to delineate the effect of hand dominance on strength in those without shoulder pain. Absolute and predicted strength deficits of the involved shoulder were calculated via regression analysis. Pearson's correlation coefficients were computed between age and strength. RESULTS: Utilizing the contralateral extremity as an internal control eliminates age as a confounding variable in predicting strength outcomes (r = 0.093). CONCLUSION: Allometric concepts, applied to shoulder strength assessment, eliminates age as a confounding variable. Strength testing of both shoulders should be considered in the development of future shoulder outcome scales in order to eliminate the strong influence of age.

Adult↗

PubMed2004

Characterization of melanophore morphology by fractal dimension analysis.

Fractal or focal dimension (FD) analysis is a valuable tool to identify physiologic stimuli at the cellular and tissue levels that allows for quantification of cell perimeter complexity. The FD analysis was determined on fluorescence images of caffeine- or epinephrine-treated (or untreated control) killifish Fundulus heteroclitus (Linneaus) melanophores in culture. Cell perimeters were indicated by rhodamine-phalloidin labeling of cortical microfilaments using box-counting FD analysis. Caffeine-treated melanophores displayed dispersed melanosomes in cells with less serrated edges and reduced FD and complexity. Complexity in epinephrine-treated cells was significantly higher than the caffeine-treated cells or in the control. Cytoarchitectural variability of the cell perimeter is expected because cells change shape when cued with agents. Epinephrine-treated melanophores demonstrated aggregated melanosomes in cells with more serrated edges, significantly higher FD and thus complexity. Melanophores not treated with caffeine or epinephrine produced variable distributions of melanosomes and resulted in cells with variably serrated edges and intermediate FD with a larger SE of the regression and greater range of complexity. Dispersion of melanosomes occurs with rearrangements of the cytoskeleton to accommodate centrifugal distribution of melanosomes throughout the cell and to the periphery. The loading of melanosomes onto cortical microfilaments may provide a less complex cell contour, with the even distribution of the cytoskeleton and melanosomes. Aggregation of melanosomes occurs with rearrangements of the cytoskeleton to accommodate centripetal distribution of melanosomes. The aggregation of melanosomes may contribute to centripetal retraction of the cytoskeleton and plasma membrane. The FD analysis is, therefore, a convenient method to measure contrasting morphologic changes within stimulated cells.

Animals↗

PubMedDate not supplied

Persistence of chromosome aberrations following acute radiation: II, does it matter how translocations are scored?

Chromosome breaks and rearrangements resulting from ionizing radiation can be much more complicated than many investigators thought possible some years ago. The realization that not all translocations are reciprocal, that multiway exchanges occur, and that some double-strand breaks are not repaired prior to mitosis have all contributed to the difficulty of knowing how best to identify, record, evaluate, and report chromosome translocations. Here we describe the results of a series of experiments in which blood from two normal healthy subjects was obtained, irradiated with 137Cs gamma-rays in vitro at doses ranging from 0 (controls) to 4 Gy, and cultured. Cells from each dose group and donor were harvested at days 2, 2.5, 3, 4, 5, and 7 and evaluated for chromosome damage by simultaneously painting chromosomes 1, 2, and 4 in red and 3, 5, and 6 in green. The persistence of dicentrics, fragments, rings, insertions, and PAINT translocations are reported separately by us in this issue. In this article, we focus on translocations, characterizing the various types in detail and comparing and contrasting their persistence across all dose groups for both donors. The results indicate that the persistence of all translocation types was sufficient to be used for retrospective dosimetry, although nonreciprocal translocations exhibited diminished persistence compared to the other types. We also characterize the kinetics of the radiation dose responses of the two donors who exhibited significant differences in the induction as well as the persistence of translocations. Based on the evidence presented here, we hypothesize that these individuals differ in the recognition and repair of radiation-induced damage as well as in cell cycle checkpoint control. Despite these differences, the temporal frequency of translocation losses at both the high and low doses was similar for both subjects.

Adult↗

PubMedDate not supplied

Persistence of chromosome aberrations following acute radiation: I, PAINT translocations, dicentrics, rings, fragments, and insertions.

Chromosome translocations are used to estimate the doses of radiation received following occupational or accidental exposure. Biodosimetry relies on the assumption that translocations are not cell-lethal and persist with little or no loss over time. While translocations do exhibit substantially greater persistence than other aberration types (e.g., dicentrics), there is evidence that translocation frequencies also decline over time, at least following acute doses above 1 Gy. To the extent that translocation frequencies decline, the predicted absorbed doses will be underestimated. Yet unknown is whether translocations induced by ionizing radiation at doses below 1 Gy also show significant declines. Here we report on the persistence of translocations induced by 137Cs gamma-rays at acute doses ranging from 0.2 to 4 Gy using peripheral blood lymphocytes from two unrelated healthy male donors. Chromosome aberrations were evaluated by simultaneously painting chromosomes 1, 2, and 4 in red and 3, 5, and 6 in green in cells harvested 2-7 days following exposure and were scored using the PAINT system. Translocations were also enumerated using several other methods and these results are reported separately by us in this issue. For comparison, the persistence of dicentrics, rings, acentric fragments, and color junctions was also evaluated and showed rapid losses with time. The results from both donors provide evidence that translocation frequencies decline with time in a statistically significant manner at doses as low as 0.2-0.3 Gy. The frequency of translocations for all dose groups declined from day 2 to 7 by averages of 39% and 26% for donors 1 and 2, respectively. These data emphasize the importance of considering translocation loss in biological dosimetry long times after exposure.

Adult↗