Balo’s concentric sclerosis: Value of magnetic resonance imaging in diagnosis

We report two cases of Balo’s concentric sclerosis that demonstrate the typical magnetic resonance imaging (MRI) findings of concentric rings of demyelination involving the superficial and deep white matter and sparing the cortex. In both cases biopsy was not performed as MRI findings and multi-mode evoked potential studies were consistent with demyelinating illness. The theories regarding the pathogenesis of this peculiar appearance are briefly reviewed.     

HPLC-MS analysis of Schisandra lignans and their metabolites in Caco-2 cell monolayer and rat everted gut sac models and in rat plasma

The absorption profiles of Schisandra chinensis were evaluated using the human Caco-2 cell monolayer and rat everted gut sac models, as well as in rat plasma. By analyzing the chromatographic and MSⁿ characteristics of individual peak acquired by HPLC-DAD-APCI-MSⁿ determination, thirteen lignans were identified as the major in vitro absorbable components of the Schisandra extract. Most of these compounds were also detected and identified in rat plasma after an oral administration of the Schisandra extract, except for angeloyl(tigloyl)gomisin H and angeloyl(tigloyl)gomisin Q, whose structures possess an ester group at the cyclooctadiene ring. In addition, four metabolites, corresponding to the hydroxylation and demethylation products of schisandrin and the hydrolysis derivative of angeloyl(tigloyl)gomisin Q, were tentatively identified. The results demonstrate that Schisandra lignans are the major absorbable components of this crude drug, and hydroxylation, demethylation and hydrolysis are important metabolic transformations of the absorbable lignans.     

Determination of the DDE and PCB contents of peregrine Falcon eggs: A comparison of whole egg measurements and estimates derived from eggshell membranes

A method using eggshell membranes to determine egg content levels of DDE and polychlorobiphenyls (PCBs), two of the most ubiquitous environmental contaminants, has been validated. A comparison was made between the residue levels determined from the egg contents of 40 Peregrine Falcon (Falco peregrinus) eggs and from hexanesoluble extracts of the dried eggshell membranes. The results confirm the use of museum eggshells for estimations of DDE and PCB levels of the original egg contents. This method should be valid for other lipophilic compounds. The data generated are of use not only to determine the records of past contamination, but may be expected to provide useful information on patterns of contamination encountered in different geographical areas. The membrane extraction technique allows pollutant levels to be measured without removing viable material from endangered species.     

Apoptosis and proliferation under conditions of deoxynucleotide pool imbalance in liver of folate/methyl deficient rats

Weanling male F344 rats were fed either a semi-purified diet low in methionine and lacking in choline and folic acid (folate/methyl deficient) or a supplemented control diet for periods of 2, 5, 7 days, 3 weeks, and 9 weeks. Two days after initiating the folate/methyl deficient diet in weanling F344 rats, the incidence of apoptotic bodies, identified by in situ end-labeling of 3'-OH DNA strand breaks, was significantly increased in liver sections from the deficient rats. Apoptotic cell death was confirmed biochemically by an increase in nuclear Ca2+/Mg2+-dependent endonuclease activity that paralleled the increase in apoptotic bodies over the 9-week feeding period. There was no morphologic evidence of necrotic foci or necrosis-associated inflammatory response over the 9-week period. Confirming that cell turnover is chronically elevated in this model, the increase in apoptotic rate was accompanied by a sustained increase in the mitotic index (MI). The DNA repair-associated enzyme, poly(ADPribose) polymerase (PARP), was similarly elevated and was associated with significant decreases in the substrate for ADPribose polymer synthesis, nicotinamide adenine dinucleotide (NAD). Because folate metabolites are essential for de novo purine and thymidine biosynthesis, prolonged deficiency in folic acid can induce an imbalance in the deoxynucleotide precursors for DNA replication/repair and negatively affect the fidelity of DNA synthesis. Using an HPLC method, hepatic deoxyuridine triphosphate (dUTP) levels were increased at 3 and 9 weeks after initiation of the deficient diet and levels of thymidine triphosphate (dTTP) were reduced. An increase in dUTP/ dTTP ratio is consistent with a block in folate-dependent de novo thymidylate biosynthesis and may predispose to uracil misincorporation and DNA repair-related DNA strand breaks.      

Selective estrogen receptor modulators in chronic renal failure

BACKGROUND: In addition to renal osteodystrophy, postmenopausal women on dialysis could be at risk of osteoporosis. Hormone replacement therapy (HRT) could have beneficial effects as well as potentially serious risks, especially in uremic women, due to the pharmacokinetics of estradiol in renal failure. Therapeutic alternatives, such as the selective estrogen receptor modulators (SERMs), have shown the benefits of estrogen on bone and serum lipid levels, without its adverse effects on the breast and endometrium, in nonuremic women. METHODS: Recent data on the effect of the SERM raloxifene in bone and lipid metabolism in osteoporotic postmenopausal women on dialysis is reviewed. Since the estrogen receptor (ER) gene has been suggested as a candidate marker for osteoporosis, we investigated whether ER polymorphism could have predicted the BMD response to raloxifene. RESULTS: Hemodialyzed women on raloxifene demonstrated increased trabecular bone mineral density (BMD) and decreased bone resorption markers. Similarly, LDL-cholesterol values dropped significantly. ER gene polymorphism analysis of baseline BMD parameters did not differ between PP/xx or Pp/Xx groups. Nevertheless, patients on raloxifene with PP/xx genotypes, but not those with Pp/Xx, showed a higher trabecular BMD after one year on treatment, suggesting that homozygous women for P or x alleles of the ER have a better BMD response to raloxifene. CONCLUSION: Raloxifene and, most likely, other SERMs, could represent a good alternative to HRT in postmenopausal uremic women.