Sources of interracial variation in bone mineral density

Many studies have demonstrated significant differences in bone mineral density between various racial groups. Although it has been suggested that differences in body weight contribute to such interracial variation, the artifactual effect of the skeletal size inherent in projectional absorptiometry methods has been largely ignored. We have measured bone mineral density by dual-energy X-ray absorptiometry in the lumbar spine and at three femoral sites in 200 premenopausal women of Chinese, Indian, European, or Polynesian origin (50 of similar mean age in each group). In the Chinese and Indian women the measured bone mineral density measurements (g/cm2) were similar, but significantly less, at all sites, than those of European women (p < or = 0.005). The European women were, however, significantly taller than both the Chinese and Indian women (p < 0.0001), and when the scale artifact of absorptiometry was removed by dividing the measured bone mineral density either by the height of the subject, or by the square root of the area over which the X-ray beam was projected, then the differences in mean bone mineral density between the Chinese, Indian, and European women were almost completely eliminated. The Polynesian women were significantly more obese (as judged from mean body mass index) than all the other groups (p < 0.0001) and had significantly greater bone mineral density at all sites than all the other groups both before (p < 0.0001) and after (p < 0.0001) correcting for the scale artifact.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of rheological and mucoadhesive properties of three grades of chitosan hydrochloride

In the present study the rheological and mucoadhesive properties of three viscosity grades of a cationic polymer, chitosan, were investigated to assess the suitability of this polymer for gastroadhesive formulations. The influence of the pH, ionic strength and temperature of the hydration medium on the rheological properties was studied. The mucoadhesive performance was assessed in vitro by means of rheological synergism and tensile stress testing. A correlation was found between rheological synergism and tensile parameters (force of detachment and work of adhesion), which proves that both methods can correctly predict the mucoadhesive performance of the polymers examined. It was found that the interaction of chitosan with mucin decreases on increasing molecular weight.     

Santolindiacetylene, a polyacetylene derivative isolated from the essential oil of Santolina canescens

The yield, composition, and some pharmacological activities (hepatoprotective and antioxidant) of the essential oil of Santolina canescens aerial parts have been investigated. The essential oil qualitative data were determined by gc and gc-ms. The main component, santolindiacetylene [1], was isolated and characterized by spectral methods, and the structure assigned as 1-(2'-naphthyl)hexa-2,4-diyne. The protective activities of the essential oil and its main component [1] were evaluated against carbon tetrachloride-induced hepatotoxicity in a rat model. In both cases a significant hepatoprotective effect was observed, as evident from the strong decrease of elevated GPT serum levels caused by carbon tetrachloride-induced hepatic damage.     

A histochemical study of the biological effects of sodium dodecyl sulfate on the intestine of the gilthead seabream, Sparus aurata L

Infantile myofibromatosis (IMF) is a distinct clinicopathologic entity characterized by solitary or multicentric tumors present at birth or in early infancy with a typical biphasic (central hemangiopericytoma-like, peripheral leiomyoma-like) histologic pattern. We present a case of IMF in two siblings with onset of disease in late childhood. Histology of the primary as well as several later tumors was characterized by a monophasic cellular appearance with a prominence of tiny capillaries initially suggesting an unusual vascular tumor. Diagnosis was established by the development of more characteristic biphasic lesions during the course of disease. Immunocytochemistry (Ulex, factor VIII, JC/70A [CD31], PAL-E, BMA120, EN4, QBEnd10 [CD34], SMS actin) and ultrastructural studies showed no (marked) differences between different types of IMF. The monophasic cellular pattern should be recognized as an unusual histologic manifestation of IMF, in particular in patients outside the classical setting or presentation.     

Extensive platelet activation in preeclampsia compared with normal pregnancy: enhanced expression of cell adhesion molecules

OBJECTIVES: Platelets play an important role in the pathophysiologic mechanisms of preeclampsia. Our purpose was to investigate by means of flow cytometry to what extent platelets circulate in an activated state during normal pregnancy and whether this activation is more extensive in preeclampsia. STUDY DESIGN: Platelets in whole blood from 10 preeclamptic third-trimester pregnant women (highest diastolic blood pressure range 100 to 130 mm Hg, proteinuria range 0.59 to 11.5 gm/24 hr) and from 10 normotensive third-trimester pregnant controls were analyzed with the following activation markers: anti-P-selectin (alpha-granule secretion), anti-CD63 (lysosomal secretion), PAC-1 (monoclonal antibody against fibrinogen receptor conformation of the glycoprotein IIb/IIIa complex), anti-platelet endothelial cell adhesion molecule-1, and annexin-V (a placental protein that binds to negatively charged phospholipids, present on the outside of the platelet plasma membrane after activation). The differences in surface antigen exposure between the two groups were determined by double-label flow cytometry. Flow cytometric data were analyzed in two ways: first, the percentages of activated platelets above a certain threshold compared with a nonpregnant control sample were determined, indicative for activation of a subpopulation of cells, and, second, the mean fluorescence intensities were determined, indicative of the mean surface antigen expression of the total platelet population. RESULTS: Analysis of the percentage of activated platelets proved most informative. With this analysis an enhanced platelet activation status was present in 4 of 10 normotensive patients and a more extensive platelet activation status in all 10 preeclamptic patients, as indicated by P-selectin (p = 0.008) and CD63 (p = 0.03) expression. Increased platelet endothelial cell adhesion molecule-1 (p = 0.005) expression was also observed in preeclampsia. CONCLUSIONS: Flow cytometric analysis clearly indicated that platelets circulate in a more extensively activated state during preeclampsia than during normal pregnancy. The increased platelet endothelial cell adhesion molecule-1 expression in preeclamptic patients demonstrates that, besides alpha-granular and lysosomal release, other hitherto unknown mechanisms are involved. Platelet endothelial cell adhesion molecule-1 appears to be the best marker to distinguish preeclamptic patients from normotensive pregnant women. Only a subpopulation of the platelets appears to be activated.     

Increased levels of plasma cholesteryl ester hydroperoxides in patients with subarachnoid hemorrhage

The pathophysiology of subarachnoid hemorrhage (SAH) may involve free radical production and lipid peroxidation. We examined plasma levels of cholesteryl ester hydroperoxides (CEOOH) and antioxidants in 25 patients with SAH, and 10 neurologic controls with lacunar stroke. Patients with SAH had significantly increased plasma levels of CEOOH, which peaked on day 5 after the ictus. Concentrations of CEOOH were significantly increased, and ascorbic acid concentrations were significantly decreased in patients who developed vasospasm compared with patients without vasospasm. Increased levels of CEOOH were associated with increased mortality and correlated with clinical outcome scales. These results implicate oxidative stress in the pathogenesis of SAH and suggest that measurements of CEOOH in plasma may be useful both prognostically as well as in monitoring therapeutic interventions.