Biomedical subjects
Publications and source records attributed to M Feingold.
We report on 2 unrelated patients with microcephaly, lymphedema, and chorioretinal changes. They are compared with previously reported patients with microcephaly and lymphedema and microcephaly with chorioretinal changes. The question is raised whether all of these patients represent one entity or are separate syndromes. Until more data are available we propose that our patients represent a single entity.
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Principal components analysis is a statistical method that is used to reduce and explore data to facilitate further analyses. This method was applied to bone mineral densities measured at seven sites in 109 black and 44 white women, ages 22-80, at an internal medicine clinic in urban Detroit. We excluded subjects with a history of diseases or drugs known to affect bone metabolism. Principal components analysis was used to summarize the interrelationship of the densities and yielded two major results. First, the seven site measurements were reduced to a single, composite index (PC1) of skeletal mass that accounted for 73% of the variation in density among subjects. PC1 had roughly equal weights among the sites. A second combination of the seven sites indicated that the contrast between axial and appendicular regional densities accounted for another 10% of the variation among subjects. In investigating the relationship of density to age, body mass index, and ethnic group, we found that the principal components composite index had a stronger correlation with age (r = -0.58) and with body mass index (r = 0.34) than almost all of the regional densities. Black-white differences were larger for the composite index than for any single site density. A multiple regression of the composite index on ethnicity, body mass index, and age yielded a larger R2 (0.46) than any of the individual site densities. The second principal component, although of theoretical interest, showed a minimal ability to discriminate among subjects using the three independent variables of this study.
We sought to evaluate the utility of quantitative sensory testing (QST) and nerve conduction velocity (NCV) studies as measures of distal symmetric polyneuropathy (DSP). We studied 36 diabetic patients divided into four clinical categories of increasing severity. QST included thermal testing and vibration thresholds. NCV studies included median, peroneal, and sural nerves. Results of QST and NCV were compared among clinical groups using survival methodology. The log-rank statistic showed significant differences among the groups; the direction of the differences were consonant with clinical severity. For each diabetic patient, the result of each measurement was classified as normal or abnormal; more diabetic patients had abnormal NCV than either vibration tests or thermal tests. In conclusion, findings of QST and NCV are in keeping with clinical categorization of patients, QST and NCV are complementary tests, and the sural sensory study is the best single predictor of DSP.
We compared dual-energy x-ray absorptiometry (DXA) for measurement of the radius with the conventional single-photon absorptiometry (SPA) method. To evaluate reproducibility, 34 healthy male and female subjects were measured twice each by both methods. While the instruments measured bone mineral content (BMC) similarly, projected area was consistently lower by SPA and therefore bone mineral density (BMD) was higher by an average of 10%. We report similar coefficients of variation for the two methods, which are 0.8% (SPA) and 0.7% (DXA) for BMC (P = 0.71) and 0.8% (SPA) and 1.4% (DXA) for BMD (P = 0.02). We also evaluated the relationship between the methods with data from 196 clinic patients who were measured once each on both instruments. The BMD measurements from the two instruments were highly correlated (r = 0.97) in these patients, which permits the conversion of databases from SPA to DXA-equivalents. We conclude that DXA can replace SPA for radial bone densitometry.
We measured aortic pressure during clinically apparent cardiac electromechanical dissociation (EMD). Patients with pulse pressures were designated as having pseudo-EMD; those without, as having true EMD. Of the 200 patients studied, 54 presented with EMD, and 40 others developed it during resuscitation. Of the 94 with EMD, 39 were found to have pseudo-EMD. We compared the two types of EMD for electrocardiographic duration, return of palpable pulses, and response to standard- and high-dose epinephrine. The mean resting aortic pressure was 18 +/- 11 mm Hg in patients with true EMD and 28 +/- 11 mm Hg in those with pseudo-EMD. The mean pulse pressure in patients with pseudo-EMD was 6.3 +/- 3.5 mm Hg. Patients with pseudo-EMD had a higher proportion of witnessed arrests, higher PaO2, and lower PaCO2 than patients with true EMD. Patients with pseudo-EMD had shorter QR and QRS durations than patients with true EMD. They had a better response to standard- and high-dose epinephrine than patients with true EMD. Many patients diagnosed clinically to be in EMD have mechanical cardiac activity; this should be considered when interpreting the results of cardiac arrest research.
Primary neoplasms of the lung composed of small cells consist of undifferentiated small cell carcinoma (UCS), carcinoid tumors (CT) and some non-small cell carcinomas (NonSC) that lack cytoplasmic differentiation. The cytologic identification of tumors from specimens obtained via bronchoscopy sometimes presents difficulties due to overlapping patterns. In order to define additional differentiating criteria, we evaluated Papanicolaou-stained smears from 30 histologically proven cases, 10 from each of the three groups, with statistical analysis of computer-assisted morphologic measures. We identified significant differences between NonSC versus USC and NonSC versus CT with regard to nuclear and cytoplasmic dimensions (P less than .0001) but not between USC and CT. The nuclear:cytoplasmic ratios were similar in all three groups (P = .39). From this preliminary study we conclude that morphometric analysis can distinguish NonSC from USC and CT but not USC from CT.
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We studied the effect of standard and high doses of epinephrine on coronary perfusion pressure during cardiopulmonary resuscitation in 32 patients whose cardiac arrest was refractory to advanced cardiac life support. Simultaneous aortic and right atrial pressures were measured and plasma epinephrine levels were sampled. Patients remaining in cardiac arrest after multiple 1-mg doses of epinephrine received a high dose of 0.2 mg/kg. The increase in the coronary perfusion pressures was 3.7 +/- 5.0 mm Hg following a standard dose, not a statistically significant change. The increase after a high dose was 11.3 +/- 10.0 mm Hg; this was both statistically different than before administration and larger than after a standard dose. High-dose epinephrine was more likely to raise the coronary perfusion pressure above the previously demonstrated critical value of 15 mm Hg. The highest arterial plasma epinephrine level after a standard dose was 152 +/- 162 ng/mL, and after a high dose, 393 +/- 289 ng/mL. Because coronary perfusion pressure is a good predictor of outcome in cardiac arrest, the increase after high-dose epinephrine may improve rates of return of spontaneous circulation.
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Black and white women in the United States differ with respect to bone mass and the risk of developing osteoporosis. It has been suggested that greater body size among U.S. blacks may contribute to greater bone density in this group. It is not known whether the fat or lean component contributes more to this relationship. Bone density was measured at seven sites in 161 normal black and white women using single and dual photon absorptiometry. The first principal component accounted for 73% of the variance in the sample and constitutes an index of skeletal mass. The second principal component added another 10% and contrasts the axial and appendicular sites. Both the regional bone densities and the first principal component showed significantly greater bone densities for blacks; adjustment for body size reduced bone mass differences by approximately 50%. Body composition analysis done on a subset of these women indicated that the fat component of body mass may be the more important factor in its effect on bone mass.
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