Factors affecting the relationship between quantitative polymerase chain reaction (qPCR) and culture-based enumeration of Enterococcus in environmental waters.

AIMS: To determine the extent to which discrepancies between qPCR and culture-based results in beach water quality monitoring can be attributed to: (i) within-method variability, (ii) between-method difference within each method class (qPCR or culture) and (iii) between-class difference. METHODS AND RESULTS: We analysed 306 samples using two culture-based (EPA1600 and Enterolert) and two qPCR (Taqman and Scorpion) methods, each in duplicate. Both qPCR methods correlated with EPA1600, but regression analyses indicated approximately 0·8 log10 unit overestimation by qPCR compared to culture methods. Differences between methods within a class were less than half of this and were minimal for between-replicate within a method. Using the 104 Enterococcus per 100 ml management decision threshold, Taqman qPCR indicated the same decisions as EPA1600 for 87% of the samples, but indicated beach posting for unhealthful water when EPA1600 did not for 12% of the samples. After accounting for within-method and within-class variability, 8% of the samples exhibited true between-class discrepancy where both qPCR methods indicated beach posting while both culture methods did not. CONCLUSION: Measurement target difference (DNA vs growth) accounted for the majority of the qPCR-vs-culture discrepancy, but its influence on monitoring application is outweighed by frequent incorrect posting with culture methods due to incubation time delay. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to quantify the frequency with which culture-vs-qPCR discrepancies can be attributed to target difference - vs - method variability.

Effectiveness of qPCR permutations, internal controls and dilution as means for minimizing the impact of inhibition while measuring Enterococcus in environmental waters.

AIMS: Draft criteria for the optional use of qPCR for recreational water quality monitoring have been published in the United States. One concern is that inhibition of the qPCR assay can lead to false-negative results and potentially inadequate public health protection. We evaluate the effectiveness of strategies for minimizing the impact of inhibition. METHODS AND RESULTS: Five qPCR method permutations for measuring Enterococcus were challenged with 133 potentially inhibitory fresh and marine water samples. Serial dilutions were conducted to assess Enterococcus target assay inhibition, to which inhibition identified using four internal controls (IC) was compared. The frequency and magnitude of inhibition varied considerably among qPCR methods, with the permutation using an environmental master mix performing substantially better. Fivefold dilution was also effective at reducing inhibition in most samples (>78%). ICs were variable and somewhat ineffective, with 54-85% agreement between ICs and serial dilution. CONCLUSIONS: The current IC methods appear to not accurately predict Enterococcus inhibition and should be used with caution; fivefold dilution and the use of reagents designed for environmental sample analysis (i.e. more robust qPCR chemistry) may be preferable. SIGNIFICANCE AND IMPACT OF THE STUDY: Suitable approaches for defining, detecting and reducing inhibition will improve implementation of qPCR for water monitoring.

Method repeatability for measuring Enterococcus in southern California beach sands.

AIMS: A recent study that evaluated 22 methods for enumerating faecal indicator bacteria in sand recommended standardization to a preferred method, but all researchers involved in that study had extensive experience in processing sand samples. The purpose of this study was to evaluate how well the recommended method can be transferred to laboratories without such experience. METHODS AND RESULTS: Eight southern California laboratories that rarely measure bacteria in sand processed six sand and three water samples in replicates to assess repeatability. Among-laboratory variability was found to be less than within-laboratory variability, with no significant differences in results among any of the laboratories. Moreover, within-laboratory variability was comparable between the sand and water samples, indicating that the elution procedure added little additional method error even when performed by laboratories without prior experience. CONCLUSIONS: The simple extraction method for enumerating Enterococcus in beach sands was easily transferable to and repeatable among laboratories with little or no prior experience. SIGNIFICANCE AND IMPACT OF THE STUDY: The demonstrated success of technology transfer will further demonstrate the success of method standardization and adoption, aiding in understanding of how sands affect surface water quality.

Faecal indicator bacteria enumeration in beach sand: a comparison study of extraction methods in medium to coarse sands.

AIMS: The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. METHODS AND RESULTS: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. CONCLUSIONS: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. SIGNIFICANCE AND IMPACT OF THE STUDY: Method standardization will improve the understanding of how sands affect surface water quality.

Assessing ecological integrity in marine waters, using multiple indices and ecosystem components: challenges for the future.

During the last decade, there have been substantial scientific advances in the development of indices that measure the condition of biological ecosystem elements in coastal and estuarine waters. Though successful, these advances were only the initial steps and a special session on use of indices in ecological integrity assessments was held at the Coastal and Estuarine Research Federation meeting to focus the field on the most appropriate directions for the next decade. The session identified four primary scientific challenges: (i) reduce the array of indices by identifying the index approaches that are most widely successful; (ii) establish minimum criteria for index validation; (iii) intercalibrate methods to achieve uniform assessment scales across geographies and habitats; and (iv) integrate indices across ecosystem elements. Where an explosion of indices characterized the last decade, the next decade needs to be characterized by consolidation. With increased knowledge and understanding about the strengths and weaknesses of competing index approaches, the field needs to unify approaches that provide managers with the simple answers they need to use ecological condition information effectively and efficiently.

Obesity in C57BL/6J mice is characterized by adipose tissue hypoxia and cytotoxic T-cell infiltration.

BACKGROUND: Obesity is currently viewed as a state of chronic low-grade inflammation in which there is a pro-inflammatory alteration in the serum adipocytokine profile as well as an infiltration of white adipose tissue by activated macrophages. The etiology of this inflammation, however, is poorly understood. METHODS: Hypothesizing that local hypoxia within expanding white adipose tissue depots may contribute to obesity-related inflammation, we compared body composition, serum inflammatory marker concentrations and the expression of several hypoxia-regulated genes in white adipose tissue derived from lean, dietary-induced obese (DIO) and ob/ob male C57BL/6J mice. We also examined white adipose tissue for the presence of hypoxia using both a pimonidazole-based antibody system and a fiberoptic sensor for real-time pO(2) quantification in vivo. Finally, using cell-specific leukocyte antibodies, we performed immunohistochemistry and flow cytometric analyses to further characterize the cellular nature of adipose inflammation. RESULTS: We determined that obesity in male C57BL/6J mice is associated with increased expression of HIF (hypoxia-inducible factor) isoforms and GLUT-1, and that white adipose tissue hypoxia was present in the obese mice. Immunohistochemistry revealed hypoxic areas to colocalize predominantly with F4/80+ macrophages. Interestingly, CD3+ T cells were present in large numbers within the adipose of both DIO and ob/ob obese mice, and flow cytometry revealed their adipose to possess significantly more CD8+ T cells than their lean cohort. CONCLUSIONS: White adipose hypoxia and cytotoxic T-cell invasion are features of obesity in C57BL/6J mice and are potential contributors to their local and generalized inflammatory state.

Proteasome inhibitors, including curcumin, improve pancreatic ß-cell function and insulin sensitivity in diabetic mice.

BACKGROUND: Type 2 diabetes stems from obesity-associated insulin resistance, and in the genetically susceptible, concomitant pancreatic ß-cell failure can occur, which further exacerbates hyperglycemia. Recent work by our group and others has shown that the natural polyphenol curcumin attenuates the development of insulin resistance and hyperglycemia in mouse models of hyperinsulinemic or compensated type 2 diabetes. Although several potential downstream molecular targets of curcumin exist, it is now recognized to be a direct inhibitor of proteasome activity. We now show that curcumin also prevents ß-cell failure in a mouse model of uncompensated obesity-related insulin resistance (Lepr(db/db) on the Kaliss background). RESULTS: In this instance, dietary supplementation with curcumin prevented hyperglycemia, increased insulin production and lean body mass, and prolonged lifespan. In addition, we show that short-term in vivo treatment with low dosages of two molecularly distinct proteasome inhibitors celastrol and epoxomicin reverse hyperglycemia in mice with ß-cell failure by increasing insulin production and insulin sensitivity. CONCLUSIONS: These studies suggest that proteasome inhibitors may prove useful for patients with diabetes by improving both ß-cell function and relieving insulin resistance.

vFLIP protects PC-12 cells from apoptosis induced by Sindbis virus: implications for the role of TNF-alpha.

Sindbis virus (SV) is an alphavirus used as a model for studying the pathogenesis of viral encephalitis. In this study we examined the effects and the mechanisms involved in the apoptosis induced by SV in PC-12 cells, and the role of a vFLIP in this process. Infection of PC-12 cells with a neurovirulent strain of SV, SVNI, induced cell apoptosis. Overexpression of vFLIP encoded by the HHV-8 or treatment with a caspase-8 inhibitor inhibited cell apoptosis. SVNI induced an increase in the expression of tumor necrosis factor alpha (TNF-alpha), and pre-treatment of the cells with an anti-TNF-alpha blocking antibody or with soluble TNF-alpha receptor abrogated the apoptotic effect of SVNI. Moreover, TNF-alpha R1 knockout mice were more resistant to the cytopathic effects of the virus as compared to control animals. Our results indicate that the apoptosis induced by SVNI is mediated by activation of caspase-8, and that TNF-alpha plays an important role in the apoptotic response.

Randomized placebo-controlled multicenter evaluation of diethyldithiocarbamate for chemoprotection against cisplatin-induced toxicities.

PURPOSE: Diethyldithiocarbamate (DDTC) blocks cisplatin-induced toxicities in animal models without inhibiting antitumor effects. DDTC chemoprotection was tested in a randomized, multicenter, double-blind comparison versus placebo (PB) in patients with lung or ovarian cancer. Primary end points were nephrotoxicity, ototoxicity, neuropathy, and completion of therapy. PATIENTS AND METHODS: Between April 1990 and February 1992, 221 patients were registered with small-cell lung cancer (SCLC), non-small-cell lung cancer (NSCLC), or ovarian cancer. Cisplatin (100 mg/m2) and cyclophosphamide (in ovarian cancer) or etoposide (in lung cancer) were administered with either DDTC (1.6 g/m2 over 4 hours) or PB intravenously, every 4 weeks for a planned six cycles. RESULTS: At an interim safety analysis, data were available for 195 patients from the combined lung and ovarian cancer populations (PB, 99 patients; DDTC, 96 patients). Withdrawal for chemotherapy-induced toxicities occurred in 9% of PB-treated patients and 23% of DDTC-treated patients (P = .008). The mean cisplatin delivered dose-intensity (DDI) was 23 mg/m2/wk on both arms. However, the mean cisplatin cumulative dose delivered (CDD) was 379 mg/m2 on the PB arm, compared with 247 mg/m2 on the DDTC arm (P = .0001). At the time of interim analysis, 28% of PB-treated patients had completed all six cycles of therapy, compared with only 6% of DDTC-treated patients (P < .001). Although, clinical hearing loss, neuropathy, emesis, and myelosuppression were equivalent in the two treatment arms, DDTC-treated patients had more nephrotoxicity as determined by changes in serum creatinine concentration. Toxicities related to DDTC infusion included transient hypertension, flushing, and hyperglycemia. DDTC did not compromise response rates in either tumor type. CONCLUSION: This study did not demonstrate a significant chemoprotective effect against cisplatin-induced toxicities with the DDTC dose schedule tested. Patients who received DDTC received lower cumulative doses of cisplatin, but were more likely to be withdrawn from treatment early due to chemotherapy-related toxicities.

Cardioprotection with dexrazoxane for doxorubicin-containing therapy in advanced breast cancer.

PURPOSE: To determine the cardioprotective effect of dexrazoxane (DZR) used in a doxorubicin-based combination therapy in advanced breast cancer. PATIENTS AND METHODS: Between November 1988 and January 1991, 534 patients with advanced breast cancer were randomized to two multicenter, double-blind studies (088001 and 088006). Patients received fluorouracil, doxorubicin, and cyclophosphamide (FAC) with either DZR (DZR-to-doxorubicin ratio, 10:1) or placebo (PLA) every 3 weeks and were monitored with serial multiplegated acquisition (MUGA) scans. RESULTS: The hazards ratio (HR) of PLA to DZR for a cardiac event, which was predefined ejection fraction changes or congestive heart failure (CHF), was 2.63 (95% confidence interval [CI], 1.61 to 4.27; P < .001) for 088001 and 2.00 (95% CI, 1.01 to 3.96; P = .038) for 088006. The objective response rates for 088001 were 46.8% for DZR and 60.5% for PLA, a difference of 14% (95% CI, -25% to -2%; P = .019), and for 088006 were 53.7% for DZR and 49.3% for PLA, a difference of 4% (95% CI, -13% to 22%; P = .63). Time to progression and survival were not significantly different between treatment arms in either study. Toxicities on the DZR arms included lower granulocyte and platelet counts at nadir (P = .009 and P = .004, respectively) and more pain on injection (P = .001), with no difference in the rates of fever, infection, or hemorrhage. CONCLUSION: DZR had a significant cardioprotective effect as measured by noninvasive testing and clinical CHF. One of the two studies (088001) showed a lower response rate with DZR, but time to progression and survival were not significantly different. DZR is the first agent shown to reduce cardiotoxicity from doxorubicin.

Control of endogenous norepinephrine release in the hypothalamus of male rats changes over adolescent development.

In order to evaluate mechanisms that could contribute to the effect of adolescent development on the in vivo utilization of norepinephrine (NE) in the hypothalamus, the depolarized release of endogenous norepinephrine (using 50 mM potassium) was measured in vitro in hypothalamic explants from male rats over late juvenile (28 days) to young adult (70 days) ages. Depolarized release, expressed as a percent of the total endogenous pool, was significantly greater in juveniles than in either adolescents (42 days) or young adults. Incubation in the presence of idazoxan, an alpha 2-adrenoceptor antagonists, increased the depolarized fractional NE release in adolescent and young adult rats; however, the same drug decreased depolarized release in juveniles. Inhibition of norepinephrine reuptake by incubation in the presence of nisoxetine (1 microM) significantly increased depolarized release (fractional and absolute) in young adults only. A higher concentration of nisoxetine (5 microM) significantly increased depolarized release in juveniles, but significantly reduced release in adults. Nisoxetine did not influence release in adolescents at either concentration. The possibilities that adolescents development brings about a change in alpha 2-adrenoceptor subtype and that juveniles may have a greater NE reuptake capacity than adults are discussed. Hypothalamic NE projections are important to several regulatory functions, and changes that take place in this system over adolescence may be important for the emergence of adult-typical responses as well as render adolescents vulnerable to specific dysfunctions.

Adenosine receptor antagonists inhibit the development of morphine sensitization in the C57BL/6 mouse.

We examined the effects of adenosine antagonists on the development of morphine sensitization in C57BL/6 mice. Adenosine antagonists or vehicle were repeatedly co-administered intraperitoneally with morphine (10 mg/kg, s.c.) to mice once every other day for 9 days. Two days later, a 10 mg/kg morphine-only challenge was administered to each group. Consistent with sensitization, mice receiving morphine alone developed enhanced ambulatory activity responses to subsequent morphine administrations and, upon morphine-only challenge, had a significantly greater response to morphine than vehicle pretreated animals. The nonselective adenosine antagonist, caffeine, at 10 and 20 mg/kg but not at 5 mg/kg, attenuated the development of sensitization during co-administration with morphine and also following morphine-only challenge. The adenosine A1 selective antagonist 1,3-dipropyl-8-(2-amino-4-chlorophenyl)-xanthine (PACPX), at 0.001 and 0.002 mg/kg but not at 0.2 mg/kg, similarly attenuated the development of morphine sensitization. We propose a mechanism which involves an adenosine receptor role in the mesolimbic dopamine system.

Pharmacotherapy of asthma in children, with special reference to leukotriene receptor antagonists.

Asthma in adults is generally recognized as a chronic inflammatory airway disease, although this association is less well established in childhood asthma. Thus, recent asthma guidelines have emphasized that asthma treatment should be directed toward the underlying inflammatory aspects of the disease. The prevalence of asthma and resultant hospitalizations and deaths have increased or remained stable over the past 10 years in the United States. In part, this appears to be caused by shortcomings of available antiasthma therapeutic agents. Because these trends are particularly troublesome in children and young adults, there is a need for effective anti-inflammatory therapies that are safe and tolerable. The leukotrienes are a family of lipid mediators that appear to play an important role in the symptomology and pathogenesis of asthma. The results of clinical trials in adults with asthma demonstrated that antileukotriene drugs such as zafirlukast, montelukast, and zileuton improve pulmonary function, decrease asthma symptoms, and decrease the concomitant use of other antiasthma drugs. Most antileukotriene agents are orally bioavailable and well tolerated, offering the potential for improved patient compliance. Montelukast and zafirlukast have received approval for use in pediatric asthma patients, and approval of zafirlukast in this patient population is pending.

In vivo efficacy of silver-coated fabric against Staphylococcus epidermidis.

BACKGROUND AND AIM OF THE STUDY: Prosthetic valve endocarditis (PVE) is a serious complication of heart valve replacement. The use of silver-coated polyester fabric in sewing cuff fabrication is intended to reduce the incidence of PVE. In this study, three pathogenic strains of Staphylococcus epidermidis (two PVE and one peripheral vasculature pathogen) were used to evaluate infection of silver-coated and uncoated fabric. METHODS: Fabric was inoculated by preincubation for 30 min in bacterial suspensions containing 10(4), 10(5), 10(6), 10(7) or 10(8) CFU/ml, and implanted subdermally in mice for up to seven days. Bacteria adherent to fabric implanted for zero, one, three, or seven days were enumerated by sonicating the fabric and plating serial dilutions of the resulting suspension. Percent infection was assessed by implanting samples, subdermally, for seven days, then incubating explanted samples in growth media for three days and calculating the percent of fabric showing bacterial growth, for each concentration of inoculum. A logistic regression model was used to estimate curves relating percent infection to log concentration of the bacterial inoculum. These curves were used to estimate the concentration of inoculum required to produce 50% infection (ID50) for the three strains of S. epidermidis, for silver-coated and uncoated fabric. RESULTS: Direct enumeration showed no difference in bacteria adherent to silver-coated and uncoated fabric, and no bacteria present in either fabric type in samples implanted for seven days. Nevertheless, incubation of those samples in growth media showed that many of the samples were infected. The calculated ID50 was significantly lower for silver-coated fabric than for uncoated fabric, for all three strains of S. epidermidis tested. CONCLUSION: Silver-coated fabric increases resistance to infection by S. epidermidis in this direct-contamination, mouse subdermal model.

Comparison of total coliform, fecal coliform, and enterococcus bacterial indicator response for ocean recreational water quality testing.

In July 1999, California's ocean recreational bacterial water quality standards were changed from a total coliform (TC) test to a standard requiring testing for all three bacterial indicators: TC, fecal coliforms (FC), and enterococci (EC). To compare the relationship between the bacterial indicators, and the effect that changing the standards would have on recreational water regulatory actions, three regional studies were conducted along the southern California shoreline from Santa Barbara to San Diego, California. Two studies were conducted during dry weather and one following a large storm event. In each study, samples were collected at over 200 sites which were selected using a stratified random design, with strata consisting of open beach areas and rocky shoreline, and areas near freshwater outlets that drain land-based runoff. During the dry weather studies, samples were collected once per week for 5 weeks. For the storm event study, sampling occurred on a single day about 24 h following the storm. The three indicator bacteria were measured at each site and the results were compared to the single sample standards (TC > 10,000; FC > 400 and EC > 104 MPN or cfu/100 ml). EC was the indicator that failed the single sample standards most often. During the wet weather study, 99% of all standard failures were detected using EC, compared with only 56% for FC, and 40% for TC. During the Summer Study, EC was again the indicator that failed the single sample standards most often, with 60% of the failures for EC alone. The increased failure of the EC standard occurred consistently regardless of whether the sample was collected at a beach or rocky shoreline site, or at a site near a freshwater outlet. Agreement among indicators was better during wet weather than during dry weather. During dry weather, agreement among indicators was better near freshwater outlets than along open shoreline. Cumulatively, our results suggest that replacement of a TC standard with an EC standard will lead to a five-fold increase in failures during dry weather and a doubling of failures during wet weather. Replacing a TC standard with one based on all three indicators will lead to an eight-fold increase in failures. Changes in the requirements for water quality testing have strong implications for increases in beach closures and restrictions.

Comparison of bacterial indicator analysis methods in stormwater-affected coastal waters.

Membrane filtration (MF) and multiple tube fermentation (MTF) have been used for decades to measure indicator bacteria levels in beach water samples, but new methods based on chromogenic substrate (CS) technology are becoming increasingly popular. Only a few studies have compared results among these methods and they have generally been based on samples collected from a limited number of sites during dry weather. In this study, samples were collected from 108 sites the day after a major rainstorm, and three indicator bacteria (total coliforms (TCs), fecal coliforms (FCs) or E. coli, and enterococci (EC)) were each measured using MF, MTF, and CS. Sampling sites were selected using a stratified random design, stratified by open sandy beach, rocky shoreline, and beach areas near urban runoff outlets. The CS results were found to be highly correlated with both MF and MTF for all three indicators regardless of whether the samples were taken along open shoreline or near a runoff outlet. While correlated, TC values were higher using the CS method, consistent with other studies that have demonstrated false positives with this method. FC values were 12% lower with CS, reflecting the specificity of the CS method for E. coli rather than for the entire FC group. No significant differences were observed for EC, although some differences were observed within specific laboratories. Differences for all of these indicators were small enough that, when assessed categorically, there was more than 90% agreement between CS methods and either MF or MTF methods as to whether State of California Beach Water Quality Standards were met or exceeded.

Growth development and its relationship to intellectual functioning of children with phenylketonuria.

Growth measurements, including weight, height, and head circumference, of 67 early treated children with phenylketonuria (PKU) were compared to normal standards from infancy up to six years of age. Children with PKU, both girls and boys, achieved growth parameters that were similar to those of normals. Head circumference of the boys at six years of age and of the girls at three and four years of age correlated positively with IQ scores. Weight/height (W/H) ratios at one year of age correlated positively with IQ scores for boys. Similar correlations between IQs and weight/height ratios were found for girls at one, two, and three years of age.

Sexual expression of mentally retarded people: educational and legal implications.

Issues of legal consent and competency, in addition to the relevant psychological literature, were reviewed in relation to institutional policy for sexual management of mentally retarded individuals. The significance of comprehensive sex education was also discussed. Finally, suggestions were provided that minimize prejudicial treatment of mentally retarded people, without eliminating their opportunities for sexual expression.

A novel breath actuated device (Autohaler) consistently actuates during the early phase of inspiration.

OBJECTIVE: To establish and quantify the point during inspiration that the Autohaler (AH) inhalation system releases a metered dose of aerosol (placebo). The second objective was to determine if the Autohaler system actuates consistently, regardless of the canister life. DESIGN: Double-blind, randomized, two-period crossover, one-day trial. SETTING: Community based allergy and asthma clinic. PARTICIPANTS: Twelve patients with mild to moderate asthma. RESULTS: Mean verbal training time for the AH which included the patient demonstrating their ability to correctly use the AH was approximately 6 minutes. The mean time for actuation for the AH early in its canister life ("new canister") was 195 msec compared to 205 msec for the AH late in its canister life ("old canister") (p = 0.589). This represented the early part of inspiration as patients had a mean inspiratory duration of 2231 msec for the "new" AH and 2343 msec for the "old" AH. The mean percentage of inspiration time required to actuate the "new" AH was 8.92% compared to 8.82% for the "old" AH. Patients rated the system as easier to much easier to use compared with their current standard press and breathe inhaler. CONCLUSIONS: The AH consistently actuates early during inspiration, which is considered the optimal time for drug delivery, regardless of the canister life.

Changing anthropogenic influence on the Santa Monica Bay watershed.

Santa Monica Bay is an open coastal embayment located directly seaward of Los Angeles, California. The Bay provides vital economic value through its water-dependent activities, such as swimming, diving, boating, and fishing. An increase from 100,000 residents in 1900 to 10 million in 2000 has imposed numerous environmental stressors on the Bay, including urbanization of the watershed. Pollutant discharges into the Bay increased throughout the early part of the century, but declined following passage of the Clean Water Act in 1972. Since that time, the predominant source of pollutant inputs has changed from point sources to non-point urban runoff. To assess how present-day and historical pollution interact to affect the environmental quality of Santa Monica Bay, three organizations collaborated on a multi-disciplinary study in 1997, towards which this volume is focused. This paper details the temporal patterns of anthropogenic influence on Santa Monica Bay to provide context for the papers that follow.