Siberian ginseng (Eleutheroccus senticosus) effects on CYP2D6 and CYP3A4 activity in normal volunteers.

Siberian ginseng ([SG]; Eleutherococcus senticosus) is a commonly used herbal preparation. The objective of this study was to assess in normal volunteers (n = 12) the influence of a standardized SG extract on the activity of cytochrome P450 CYP2D6 and 3A4. Probe substrates dextromethorphan (CYP2D6 activity) and alprazolam (CYP3A4 activity) were administered orally at baseline and again following treatment with SG (1 x 485 mg twice daily) for 14 days. Urinary concentrations of dextromethorphan and dextorphan were quantified, and dextromethorphan metabolic ratios (DMRs) were determined at baseline and after SG treatment. Likewise, plasma samples were collected (0-60 h) for alprazolam pharmacokinetics at baseline and after SG treatment to assess effects on CYP3A4 activity. Validated high performance liquid chromatography methods were used to quantify all compounds and relevant metabolites. There were no statistically significant differences between pre- and post-SG treatment DMRs indicating a lack of effect on CYP2D6 (P > 0.05). For alprazolam there also were no significant differences in the pharmacokinetic parameters determined by noncompartmental modeling (C(max), T(max), area under the curve, half-life of elimination) indicating that SG does not significantly induce or inhibit CYP3A4 (P > 0.05). Our results indicate that standardized extracts of SG at generally recommended doses for over-the-counter use are unlikely to alter the disposition of coadministered medications primarily dependent on the CYP2D6 or CYP3A4 pathways for elimination.     

Fluorescence and photobleaching dynamics of single light-harvesting complexes

Single light-harvesting complexes LH-2 from Rhodopseudomonas acidophila were immobilized on various charged surfaces under physiological conditions. Polarized light experiments showed that the complexes were situated on the surface as nearly upright cylinders. Their fluorescence lifetimes and photobleaching properties were obtained by using a confocal fluorescence microscope with picosecond time resolution. Initially all molecules fluoresced with a lifetime of 1 ± 0.2 ns, similar to the bulk value. The photobleaching of one bacteriochlorophyll molecule from the 18-member assembly caused the fluorescence to switch off completely, because of trapping of the mobile excitations by energy transfer. This process was linear in light intensity. On continued irradiation the fluorescence often reappeared, but all molecules did not show the same behavior. Some LH-2 complexes displayed a variation of their quantum yields that was attributed to photoinduced confinement of the excited states and thereby a diminution of the superradiance. Others showed much shorter lifetimes caused by excitation energy traps that are only ≈3% efficient. On repeated excitation some molecules entered a noisy state where the fluorescence switched on and off with a correlation time of ≈0.1 s. About 490 molecules were examined.     

Sarcoid Myelopathy

A 45-year-old woman with history of iritis, uveitis, and sarcoidosis of the skin presented with a subacute cervical myelopathy. Magnetic resonance imaging (MRI) ;howed patchy, multifocal, gadoliniumenhancing intramedullary lesions of the spinal cord, and extramedullary lesions of the basal cisterns and fourth ventricle. Symptoms and MRI abnormalities were improved within 1 month of corticosteroid therapy.     

The relationship among receptive and expressive vocabulary, listening comprehension, pre-reading skills, word identification skills, and reading comprehension by children with reading disabilities.

PURPOSE: Some researchers (F. R. Vellutino, F. M. Scanlon, & M. S. Tanzman, 1994) have argued that the different domains comprising language (e.g., phonology, semantics, and grammar) may influence reading development in a differential manner and at different developmental periods. The purpose of this study was to examine proposed causal relationships among different linguistic subsystems and different measures of reading achievement in a group of children with reading disabilities. METHODS: Participants were 279 students in 2nd to 3rd grade who met research criteria for reading disability. Of those students, 108 were girls and 171 were boys. In terms of heritage, 135 were African and 144 were Caucasian. Measures assessing pre-reading skills, word identification, reading comprehension, and general oral language skills were administered. RESULTS: Structural equation modeling analyses indicated receptive and expressive vocabulary knowledge was independently related to pre-reading skills. Additionally, expressive vocabulary knowledge and listening comprehension skills were found to be independently related to word identification abilities. CONCLUSION: Results are consistent with previous research indicating that oral language skills are related to reading achievement (e.g., A. Olofsson & J. Niedersoe, 1999; H. S. Scarborough, 1990). Results from this study suggest that receptive and expressive vocabulary knowledge influence pre-reading skills in differential ways. Further, results suggest that expressive vocabulary knowledge and listening comprehension skills facilitate word identification skills.     

HIGH-LEVEL EXPRESSION OF RATD1A DOPAMINE RECEPTOR cDNA IN MOUSE FIBROBLASTLTK- CELLS BY n-BUTYRATE

1. In orefer to develop a simple, efficient system for the highlvel expression of dopamine recetors in eukaryotic cells, we have studied the effects of n-butyrate on the expression of rat D_1A dopamine receptor cDNA in mouse fibroblast LTK- cells as compared with those of n-butyrate on endogenous D₁ receptor levles in opossum kidney cells.
2. In the transfected LTK- cell mebranes with pRc/CMVD_1A receptor cDNA, a selective D₁ dopamine antagonist, [³H]-SCH 23390, exhibited a K_d of 0.9 ± 0.1 nmol/L and a B_max of 0.35 ± 0.05 pmol/mg protien (n = 5).
3. Addtion of n-butrate (2–10 mmol/L) to the culture medium for 48h dose-dependently increased the D_1A receptor level up to 1.5 ± 0.3 pmol/mg protien (n = 7), although the K_d values were not affected. The increase in receptor level was accompanined by an elevation of selective D₁ agoinist-induced adenyly cyclase activity.
4. In contrast, n-butyrate treatment (2–10 mmol/L) did not affect either endogenous D₁ receptor levels or fendoldopmainduced adenylyl cyclase activity in possum kidney cells.
5. These results sugges n-butyrate is a sueful tool for obtaining high-level expression of D_1A dopamine receptor cDNA in mouse fibroblast LTK- cells.     

Internal fixation of a capitate fracture with Herbert screws

A case of an isolated, displaced fracture of the capitate is described. This rare carpal injury was treated by internal fixation with two Herbert screws. The fracture united and the patient achieved an excellent range of wrist motion. The Herbert screw is useful in the treatment of displaced fractures of the capitate since the screw maintains reduction, compresses the fracture site, and allows early wrist motion.