Walnut polyphenolics inhibit in vitro human plasma and LDL oxidation.

Recent epidemiologic studies have associated nut consumption with a reduced incidence of cardiovascular mortality. However, little is known about the contribution of nut polyphenols to antioxidant and cardiovascular protection. In this investigation, polyphenol-rich extracts from English walnuts (Juglans regia) were studied and compared with ellagic acid for their ability to inhibit in vitro plasma and LDL oxidation, as well as their effects on LDL alpha-tocopherol during oxidative stress. In addition, the Trolox equivalent antioxidant activity (TEAC) was determined and liquid chromatography electrospray detection mass spectrometry (LC-ELSD/MS) analyses of the walnut extracts were performed. 2,2'-Azobis'(2-amidino propane) hydrochloride (AAPH)-induced LDL oxidation was significantly inhibited by 87 and 38% with the highest concentration (1.0 micromol/L) of ellagic acid and walnut extract, respectively. In addition, copper-mediated LDL oxidation was inhibited by 14 and 84% in the presence of ellagic acid and walnut extract, respectively, with a modest, significant LDL alpha-tocopherol sparing effect observed. Plasma thiobarbituric acid reacting substance (TBARS) formation was significantly inhibited by walnut extracts and ellagic acid in a dose-dependent manner, and the extracts exhibited a TEAC value greater than that of alpha-tocopherol. LC-ELSD/MS analysis of the walnut extracts identified ellagic acid monomers, polymeric ellagitannins and other phenolics, principally nonflavonoid compounds. These results demonstrate that walnut polyphenolics are effective inhibitors of in vitro plasma and LDL oxidation. The polyphenolic content of walnuts should be considered when evaluating their antiatherogenic potential.

HPLC-DAD-ESIMS analysis of phenolic compounds in nectarines, peaches, and plums.

The phenolic compounds of 25 peach, nectarine, and plum cultivars were studied and quantified by HPLC-DAD-ESIMS. Hydroxycinnamates, procyanidins, flavonols, and anthocyanins were detected and quantified. White and yellow flesh nectarines and peaches, and yellow and red plums, were analyzed at two different maturity stages with consideration of both peel and flesh tissues. HPLC-MS analyses allowed the identification of procyanidin dimers of the B- and A-types, as well as the presence of procyanidin trimers in plums. As a general rule, the peel tissues contained higher amounts of phenolics, and anthocyanins and flavonols were almost exclusively located in this tissue. No clear differences in the phenolic content of nectarines and peaches were detected or between white flesh and yellow flesh cultivars. There was no clear trend in phenolic content with ripening of the different cultivars. Some cultivars, however, had a very high phenolic content. For example, the white flesh nectarine cultivar Brite Pearl (350-460 mg/kg hydroxycinnamates and 430-550 mg/kg procyanidins in flesh) and the yellow flesh cv. Red Jim (180-190 mg/kg hydroxycinnamates and 210-330 mg/kg procyanidins in flesh), contained 10 times more phenolics than cultivars such as Fire Pearl (38-50 mg/kg hydroxycinnamates and 23-30 mg/kg procyanidins in flesh). Among white flesh peaches, cultivars Snow King (300-320 mg/kg hydroxycinnamates and 660-695 mg/kg procyanidins in flesh) and Snow Giant (125-130 mg/kg hydroxycinnamates and 520-540 mg/kg procyanidins in flesh) showed the highest content. The plum cultivars Black Beaut and Angeleno were especially rich in phenolics.

LC/ES-MS detection of hydroxycinnamates in human plasma and urine.

Hydroxycinnamates are components of many fruits and vegetables, being present in particularly high concentrations in prunes. An abundance of phenolic compounds in the diet has been associated with reduced heart disease mortality. However, little is known about the absorption and metabolism of these metabolites after normal foods are consumed. An LC--electrospray--MS method was developed to measure the concentration of caffeic acid in human plasma and urine, but it can also be applied to ferulic acid and chlorogenic acid. The limit of detection was found to be 10.0 nmol/L for caffeic acid and 12.5 nmol/L for ferulic and chlorogenic acids. The method was tested on samples of plasma and urine collected from volunteers who consumed a single dose of 100 g of prunes and increased levels were observed, demonstrating that the method is capable of detecting changes in hydroxycinnamate levels induced by dietary consumption.

Myelodysplasia and acute myeloid leukaemia following adjuvant chemotherapy for breast cancer using mitoxantrone and methotrexate with or without mitomycin.

BACKGROUND: Secondary acute myeloid leukaemia/myelodysplasia (t-AML, t-MDS) may occur following adjuvant chemotherapy for breast cancer and has been most frequently associated with alkylating agents. This complication is now being associated with an expanding list of chemotherapeutic agents including topoisomerase II poisons. Mitoxantrone is an agent with potential to cause t-AML and t-MDS and which is being used increasingly in the treatment of breast cancer. PATIENTS AND METHODS: Fifty-nine patients who received mitoxantrone as part of adjuvant chemotherapy for breast cancer between 1986 and 1992 were studied to determine the incidence of t-AML and t-MDS. RESULTS: With a median follow-up of 72 months, 2 cases of t-AML and 1 of t-MDS have occurred. CONCLUSIONS: This 5% incidence of t-AML and t-MDS is high and likely related to mitoxantrone. Whereas this agent is effective and has acceptable toxicity in advanced disease, its incorporation into adjuvant treatment regimens cannot be recommended based on this experience.

Spacing of central-peripheral transitional nodes of rat motoneurones.

Node of Ranvier distribution is examined in the two basic types of CNS-PNS transitional zone (TZ) related to rat spinal nerves. Type 1 TZ is short and lies at the cord surface. Type 2 is long and lies in the proximal part of the rootlet. Nearest neighbour distance measures the length between adjacent node centres and is a better estimate of node spacing than simple density measurements. Many nearest neighbour distances measure less than 10 microns. The nearest neighbour distance means (ca. 13.5 microns) and distributions are similar in both TZ types, suggesting that developmental influences on node separation are also similar in both locations. Fibres traversing the TZ are separated by large amounts of astrocytic tissue. This may prevent functional interaction between their closely packed nodes.