Cisplatin sensitivity/resistance in UV repair-deficient Chinese hamster ovary cells of complementation groups 1 and 3

We assessed the possible role of the human repair genes, ERCC1and ERCC3, in resistance to cisplatin-induced cytotoxicity.The UV repair-deficient Chinese hamster ovary (CHO) 43:3B [designatedERCC1(–)] cell line and its paired subline 83-J5, whichis stably transfected with the human DNA excision repair geneERCC1 [designated ERCC1(+)], were used in this study. UV repair-deficientCHO 27-1 cells [designated ERCC3(–)] and its paired sublinedesignated ‘ERCC3(+)’, which is stably transfectedwith the human DNA excislon repair gene ERCC3, were also used.In each pair of cell lines, we assessed cisplatin cytotoxicity,cellular drug accumulation and platinum-DNA adduct repair after1h drug exposures. Drug accumulation and DNA repair were assessedby atomic absorption spectrometry with Zeeman background correction.ERCC1(+) cells (IC₅₀ = 4.0 µM) were 5-fold more resistantto cisplatin than ERCC1(–) cells (IC₅₀ = 0.75 µM).ERCC1(+) cells repaired 25% of DNA lesions in cellular DNA withina 6 h time period following an IC₅₀ drug exposure and repaired48% over 24 h. No DNA repair was observed in ERCC1(–)cells during the same time periods. Both cell lines showed similarpatterns of drug accumulation. For ERCC3(–) cells (IC₅₀= 54 µM) and ERCC3(+) cells (IC₅₀ = 49 µM), theprofiles of cisplatin sensitivity and cellular drug accumulationwere similar. When treated with 50 µM cisplatin, thesecells showed similar patterns of drug accumulation, and wereequally efficient at forming and repairing lesions in cellularDNA. These data show that in UV repair-deficient CHO cells,ERCC1 confers resistance to cisplatin and confers the abilityto remove platinum from cellular DNA. In contrast, ERCC3 doesnot influence cisplatin drug sensitivity or adduct repair capability.This suggests that ERCC1 may be a determinant of cisplatin resistance,whereas ERCC3 is probably not.     

Contingency management in outpatient methadone treatment: a meta-analysis

A meta-analysis was conducted on contingency management interventions in outpatient methadone treatment settings. The outcome measure of interest was drug use during treatment, as detected through urinalysis. The results confirm that contingency management is effective in reducing supplemental drug use for these patients. The analysis of behavioral interventions yielded an overall effect size (r) of 0.25 based on 30 studies. Significant moderators of outcomes included type of reinforcement provided, time to reinforcement delivery, the drug targeted for behavioral change, number of urine specimens collected per week, and type of subject assignment. These factors represent important considerations for reducing drug use during treatment.     

Molecular mechanism of antitumor activity of taxanes in lung cancer (Review)

Lung cancer is the most common cause of cancer mortality in both male and female patients in the United States of America, as well as in the rest of the world. Over one million people are diagnosed with lung cancer every year worldwide. The taxane is one of the most powerful classes of novel antitumor agents and has become an integral part of several commonly used chemotherapy regimens in lung cancer management over the past few years. Although the ability of taxanes to disrupt microtubule dynamics is well documented, the molecular basis by which taxanes suppress cancer cell growth and induce apoptotic cell death is not clearly defined. In this review, we focus on the molecular mechanisms of the antitumor activity of taxanes (paclitaxel and docetaxel) in lung cancer, and discuss the interactions of taxanes with microtubules, the roles of cell cycle control and cell death induction in the anticancer action of taxanes, as well as the signal transduction pathways involved in the processes. In addition, we discuss the possible mechanisms of taxane resistance, because drug resistance to these anti-neoplastic agents affects therapy efficacy and is also a major obstacle in the clinic for the successful treatment of lung cancer. Understanding the molecular mechanisms underlying the antitumor effect of taxanes and the drug resistance to taxanes may lead to the design of biologically and pharmacologically targeted therapeutic strategies for taxane resistant tumors, and to the improvement of chemotherapy effect and cancer patient survival.     

Cultural tailoring for mammography and fruit and vegetable intake among low-income African-American women in urban public health centers

BACKGROUND: It is widely accepted that disease prevention efforts should consider cultural factors when addressing the needs of diverse populations, yet there is surprisingly little evidence that doing so enhances effectiveness. The Institute of Medicine has called for randomized studies directly comparing approaches that do and do not consider culture. METHODS: In a randomized trial, 1227 lower-income African-American women from 10 urban public health centers were assigned to either a usual care control group, or to receive a series of six women's health magazines with content tailored to each individual. By random assignment, these magazines were generated from either behavioral construct tailoring (BCT), culturally relevant tailoring (CRT) or both (BCT + CRT). The CRT magazines were based on four cultural constructs: religiosity, collectivism, racial pride, and time orientation. All tailored magazines sent to women ages 40-65 promoted use of mammography; magazines sent to women ages 18-39 promoted fruit and vegetable (FV) intake. Analyses examined changes from baseline to 18-month follow-up in use of mammography and servings of FV consumed daily. RESULTS: Women receiving BCT + CRT magazines were more likely than those in the BCT, CRT, and control groups to report getting a mammogram (76% vs. 65% vs. 64% vs. 55%, respectively), and had greater increases in FV servings consumed daily (+0.96 vs. + 0.43 vs. + 0.25 vs. + 0.59). CONCLUSIONS: Systematically integrating culture into tailored cancer prevention and control interventions may enhance their effectiveness in diverse populations.     

Critical appraisal of the clinical and pathologic predictors of survival after resection of large hepatocellular carcinoma

HYPOTHESIS: A subset of patients with hepatocellular carcinoma (HCC) with a diameter of 10 cm or larger may benefit from hepatic resection. DESIGN: Retrospective study of a multi-institutional database. SETTING: Five major hepatobiliary centers. PATIENTS: We identified 300 patients who underwent hepatic resection for HCC 10 cm or larger. MAIN OUTCOME MEASURES: Clinical and pathologic data were collected, and prognostic factors were evaluated by univariate and multivariate analyses. Patient survival was stratified according to a clinical scoring system and pathologic T classification. RESULTS: The perioperative mortality rate was 5%. At a median follow-up of 32 months, the median survival was 20.3 months, and the 5-year actuarial survival rate was 27%. Four clinical factors-alpha-fetoprotein of 1000 ng/mL or higher, multiple tumor nodules, the presence of major vascular invasion, and the presence of severe fibrosis-were significant predictors of poor survival (all P<.05). Patients were assigned a clinical score according to the following risk factors: 1, no factor; 2, one or two factors; or 3, three or four factors. On the basis of the clinical score, patients could be stratified into only 2 distinct prognostic groups: no factor (score of 1) vs 1 or more factors (score of 2 or 3) (P<.001). In contrast, when patients were stratified according to pathologic T classification, 3 distinct groups were identified: T1 vs T2 vs T3 and T4 combined (P<.001). Fifty-six percent of the patients with a clinical score of 2 and 20% of patients with a clinical score of 3 actually had T1 or T2 disease on pathologic examination. CONCLUSIONS: Patients with large HCCs should be considered for liver resection as this treatment is associated with a 5-year survival rate exceeding 25%. Clinical predictors should not be used to exclude patients from surgical resection because these factors do not reliably predict outcome.     

Renal cell adaptation to oxalate

Renal manifestations of chronic hyperoxaluria include nephrolithiasis and, when extreme, interstitial scarring and progressive loss of function. Exposure of cultured renal cells to oxalate has been reported to cause cell death, as well as proliferation. The current study was performed to assess the time course and cell-type specificity of these responses. Proximal (LLC-PK₁) and distal [cIMCD and primary human renal (HRC1)] renal epithelial cells, as well as interstitial KNRK cells, were exposed to oxalate (0.5–2.0 mM) for 24–72 h. The generation of reactive oxygen species (ROS) was measured using the fluorescent probe DCF, and cell number was determined with CyQuant reagent. HSP-70 expression was assessed via real time PCR and quantitative Western blot. In response to all oxalate concentrations (0.5–2.0 mM) and lengths of exposure (15 min–2 h), cultured proximal and distal renal epithelial cells and renal fibroblasts generated ROS. After 24 h, cells demonstrated initial cell death and decrease in cell numbers, but by 48–72 h adapted and grew, despite the continued presence of oxalate. This response was associated with increased expression of HSP-70 mRNA and protein. Renal cells in vivo may possess adaptive mechanisms to withstand chronic hyperoxaluria, including increased expression of chaperone molecules such as HSP-70.     

Mentoring surgeons in private and academic practice

Mentoring is an essential component of a successful career in any profession, and these relationships are beginning to be explored in great detail in academic surgery. However, it is equally important for surgeons in private practice, and this area has not received nearly as much attention in the literature. The goals for both are similar and include providing career advice, guidance, and counseling, with the only regard being the success of the junior associate. In private practice, the mentor can be a senior colleague who may or may not be part of one's group practice. In academia, it may be someone at another university, although proximity is preferable. It may be necessary to repeat the search for a mentor more than once before a successful relationship evolves. This complex process must be mastered if one is to be successful in either academia or private practice.     

Intragastric nitric oxide is abolished in intubated patients and restored by nitrite

OBJECTIVE: Nitrite in saliva is reduced to nitric oxide (NO) in the acidic stomach, and this NO may serve gastroprotective functions. We studied intragastric NO levels in healthy controls and in intubated intensive care unit patients before and after supplementation with nitrite. DESIGN: Prospective observational study involving patients and controls. SETTING: A mixed intensive care unit and a university laboratory. PATIENTS AND SUBJECTS: Eight healthy volunteers and ten intubated, mechanically ventilated intensive care unit patients. INTERVENTIONS: A tonometric catheter was first evaluated in vitro and then used for all NO measurements. In fasting controls, gastric NO levels were measured repeatedly during periods of saliva depletion and after an intragastric nitrite infusion. In patients, changes in levels of intragastric NO, nitrite in plasma and gastric juice, and S-nitrosothiols in gastric juice were measured in response to an intragastric nitrite infusion. MEASUREMENTS AND MAIN RESULTS: The tonometric catheter had a recovery of 80% with a high intraclass and interclass correlation. Median baseline NO levels in healthy volunteers were 21.6 ppm (interquartile range, 11.4-22.3 ppm) and decreased by 90% to 3.3 ppm (2.0-5.2 ppm) during 25-50 mins of saliva depletion. The NO level was restored by an intragastric nitrite infusion. Baseline NO levels in patients were almost abolished (0.1 ppm [0.07-0.4 ppm]) but increased rapidly to 124 ppm (range, 65-180 ppm) during intragastric nitrite infusion. Nitrite levels in plasma increased from 0.18 +/- 0.03 to 1.3 +/- 0.2 microM (p < .01), and levels of S-nitrosothiols in gastric juice increased from 0.12 +/- 0.09 to 6.7 +/- 1.8 microM. CONCLUSIONS: Intragastric generation of NO requires continuous delivery of nitrite-containing saliva and is almost abolished in critically ill, intubated patients. Enteral supplementation with nitrite could however fully restore gastric NO levels. Future studies will reveal if low NO levels contribute to stress ulcers and gastric overgrowth of bacteria often seen in these patients and in turn if restoring gastric NO with nitrite could be a useful therapeutic approach.     

Prevalence and Severity of Anal Incontinence in Women With and Without Additional Vaginal Deliveries After a Fourth-Degree Perineal Laceration

PURPOSE The aim of this study was to compare the prevalence and severity of anal incontinence among women who had undergone no, one, or at least two additional vaginal deliveries after sustaining a fourth-degree sphincter tear as a nullipara.METHODS We conducted a telephone survey to determine our subjects anal function. The incontinence score was determined by adding the content (flatus, liquid, and solid stool = 1, 2, and 3 points, respectively) and frequency (less than weekly, weekly, and daily = 1, 2, and 3 points, respectively) points. Severe incontinence is defined as having a score of 5 or 6 points and the incontinence having a severe effect on the subjects daily activities.RESULTS Of the 148 women interviewed, 52 had undergone zero (Group 1), 60 had had one (Group 2), and 36 had had at least two (Group 3) additional vaginal deliveries. Among the three groups, 20 of 52 (38 percent), 14 of 60 (23 percent), and 10 of 36 (28 percent), respectively, reported anal incontinence (P = 0.208). The proportion that had 1 or 2 points (8/20, 4/14, and 3/10, respectively, P = 0.75) and 3 or 4 points (10/20, 9/14, and 2/10, respectively, P = 0.097) was similar among the three groups. Two of 20 (10 percent), 1 of 14 (7 percent), and 5 of 10 (50 percent), respectively, had a score of 5 or 6 points (P = 0.012). For the three groups, 0 of 20, 0 of 14, and 4 of 10 (40 percent) reported that their incontinence had a severe effect on their daily activities (P = <0.001), and 0 of 52, 0 of 60, and 4 of 36 (11 percent) had severe incontinence (P = 0.002).CONCLUSIONS The proportion that had severe incontinence was significantly higher among women who had undergone at least two additional deliveries.Supported by a grant from East Carolina University Brody School of Medicine Faculty Research Fund.Presented at the scientific meeting of the American Urogynecologic Society, San Francisco, California, October 17 to 19, 2002.Reprints are not available.