Application of cycle dideoxy fingerprinting to screening heterogeneous populations of the equine infectious anemia virus

Nucleotide sequence heterogeneity in a population of the equine infectious anemia virus (EIAV) was investigated using a modification of the dideoxy fingerprinting (ddF) technique. PCR-amplified regions of the gag gene from EIAV isolates were ligated into plasmid vectors and used to transform bacteria. The single dideoxynucleotide sequencing step was performed using plasmid DNA prepared from individual bacterial colonies using an 35S end-labeled primer and Taq DNA polymerase. Analysis of the products of this reaction was conducted using non-denaturing polyacrylamide gel electrophoresis. Polymorphism within this gene was suggested by the presence of several distinct electrophoretic profiles. Significantly, each profile could be correlated with variations in nucleotide sequence, which demonstrates that cycle ddF (CddF) offers a rapid and sensitive approach to identify polymorphism in PCR-amplified products.     

Minimally invasive saphenous vein harvesting: endothelial integrity and early clinical results

Eddy current effects induced by switched gradients in proximal conducting structures are traditionally reduced by applying preemphasis currents whose amplitudes and decay characteristics must be set to offset the eddy current fields. We present an expeditious, localized, and quantitative method for mapping and adjusting the parameters for eddy current compensation. Mapping is based on analysis of projections as used in the fast automatic shimming technique by mapping along projections (FASTMAP). Adjustment methods are demonstrated in high-field horizontal bore systems. The proposed localized eddy current mapping technique may also be used for localized measurements in situations where asymmetric conducting structures may cause nonlinear eddy current fields, such as in interventional MRI and open magnet designs.     

The role of agricultural pesticide use in the development of non-Hodgkin's lymphoma in women

Non-Hodgkin's lymphoma has been found to be associated with agricultural pesticide use in men, but little is known about the risk in women. In a recent population-based, case-control study conducted in eastern Nebraska, no increased risk of non-Hodgkin's lymphoma was found in women who had ever lived or worked on a farm (odds ratio [OR] = 1.0). Neither the use of insecticides (OR = 0.8) nor herbicides (OR = 0.7) on the farm was associated with non-Hodgkin's lymphoma; however, the number of women who mixed or applied pesticides was small, particularly in comparison to men on farms. Small nonsignificant associations were observed among the women who personally handled insecticides (OR = 1.3) or herbicides (OR = 1.2). Women who personally handled organophosphate insecticides had a significant 4.5-fold increased risk of non-Hodgkin's lymphoma. Use of chlorinated hydrocarbon insecticides was associated with an OR of 1.6; however, the use on dairy cattle was associated with a 3-fold increased risk. Pesticide-related risks were greater among women with a family history of cancer, particularly a history of lymphatic or hematopoietic cancer among first-degree relatives.     

Common food additives are potent inhibitors of human liver 17 alpha-ethinyloestradiol and dopamine sulphotransferases

Interactions between dietary xenobiotics, drugs and biologically active endogenous compounds are a potential source of idiosyncratic adverse pathology. We have examined the inhibition of the sulphation of a number of xenobiotics and endobiotics in human liver cytosol by 15 food additives and constituents. Sulphation of dehydroepiandrosterone was resistant to inhibition by all compounds tested; however, dopamine sulphotransferase (ST) activity was inhibited strongly by (+/-)-catechin, (+)-catechin, octyl gallate, tartrazine and vanillin. Sulphation of the xenobiotic steroid 17 alpha-ethinyloestradiol (EE2) was inhibited by vanillin, erythrosin B and octyl gallate. Of these compounds, only vanillin was found to be sulphated to a significant extent by both human liver and platelets, and vanillin was determined to be a substrate for the monoamine-sulphating isoenzyme of phenolsulphotransferase. Vanillin was found to inhibit 50% of liver EE2 ST activity (IC50) at a concentration of approximately 1.3 microM and the mode of inhibition was non-competitive. The implications of these results for the adverse side effects associated with food additives and oral contraceptives are discussed.     

Phase I and pharmacologic study of paclitaxel and cisplatin with granulocyte colony-stimulating factor: neuromuscular toxicity is dose-limiting

PURPOSE: To determine the maximum-tolerated doses (MTD), the principal toxicities, and the pharmacologic behavior of high doses of Taxol (paclitaxel; Bristol-Myers Squibb, New York, NY) combined with cisplatin and granulocyte colony-stimulating factor (G-CSF). PATIENTS AND METHODS: Untreated and minimally pretreated solid-tumor patients received 24-hour infusions of Taxol on day 1 followed by cisplatin on day 2 and G-CSF, 5 micrograms/kg/d subcutaneously (SC), beginning on day 3. Treatment was repeated every 3 weeks. Starting doses of Taxol and cisplatin were 135 and 75 mg/m2, respectively. RESULTS: The development of a severe peripheral neuropathy and/or severe myalgias precluded the chronic administration of Taxol and cisplatin with G-CSF at doses greater than 250 mg/m2 and 75 mg/m2, respectively. At this dose, the mean Taxol steady-state plasma concentration (Css) exceeds concentrations capable of inducing pertinent antimicrotubule effects in vitro. The severity of the neuropathy was related to the cumulative dose of Taxol, the magnitude of the dose administered during each treatment, and the presence of a pre-existing medical disorder associated with peripheral neuropathy. A proximal myopathy of modest severity also was documented. Although severe neutropenia occurred frequently, especially at the MTD, it was rarely associated with fever (8% of courses), and absolute neutrophil counts (ANCs) less than 500/microL never persisted for more than 5 days. Responses were noted in non-small-cell lung cancer (NSCLC) and head and neck, breast, and esophageal cancers. CONCLUSION: Taxol and cisplatin doses of 250 mg/m2 and 75 mg/m2, respectively, can be administered repetitively with G-CSF to untreated and minimally pretreated patients. However, these doses are not recommended for patients with pre-existing neuropathies until additional experience in high-risk patients is obtained. Although this Taxol dose is nearly 85% higher than the dose that can be combined with cisplatin in the absence of G-CSF, this high-dose regimen should not be used outside the investigational setting until a dose-response relationship has been demonstrated for Taxol in randomized clinical trials.     

Requirements for p53 and the ATM gene product in the regulation of G1/S and S phase checkpoints

We investigated the requirements for protein p53 and the ATM gene product in radiation-induced inhibition of DNA synthesis and regulation of the cyclin E/ and cyclin A/cyclin dependent kinases (Cdks). Wild type (WT) mouse lung fibroblasts (MLFs), p53(-/-) knock-out MLFs, normal human skin fibroblasts (HSF-55), and human AT skin fibroblasts (GM02052) were used in the investigations. The absence of p53 had no significant effect on the inhibition or recovery of DNA synthesis throughout the S phase, as determined from BrdU labeling and flow cytometry, or the rapid inhibition of cyclin A/Cdks. Gamma radiation (8 Gy) inhibited DNA synthesis and progression into G2 during the first 3 h after irradiation, and the recovery of these processes occurred at similar rates in both WT and p53(-/-) MLFs. The cyclin A/Cdks were inhibited 55-70% at 1 h after irradiation in both cell types, but p21WAF1/Cip1 levels or p21 interaction with Cdk2 did not increase in the irradiated p53(-/-) MLFs. Although p53(-/-) MLFs do not exhibit prolonged arrest at a G1 checkpoint, radiation did induce a rapid 20% reduction and small super-recovery of cyclin E/Cdk2 within 1-2 h after irradiation. Similar inhibition and recovery of cyclin E/Cdk2 previously had been associated with regulation of transient G1 delay and the inhibition of initiation at an apparent G1/S checkpoint in Chinese hamster cells. In contrast, loss of the ATM gene product abrogated transient cyclin E/Cdk2 inhibition, most inhibition of DNA synthesis and all, but a 10-15% inhibition, of the cyclin A/Cdks. The results indicate that neither p53 nor p21 is required for transient inhibition of cyclin E/Cdk2 associated with the G1/S checkpoint or for inhibition of DNA synthesis at 'checkpoints' within the S phase. Conversely, the ATM gene product appears to be essential for regulation of the G1/S checkpoint and for inhibition of DNA replication associated with the inhibition of cyclin A/Cdk2. Differential aspects of DNA synthesis inhibition among cell types are presented and discussed in the context of S phase checkpoints.