Novel and Engineered Type II CRISPR Systems from Uncultivated Microbes with Broad Genome Editing Capability

Type II Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 nucleases have been extensively used in biotechnology and therapeutics. However, many applications are not possible owing to the size, targetability, and potential off-target effects associated with currently known systems. In this study, we identified thousands of CRISPR type II effectors by mining an extensive, genome-resolved metagenomics database encompassing hundreds of thousands of microbial genomes. We developed a high-throughput pipeline that enabled us to predict tracrRNA sequences, to design single guide RNAs, and to demonstrate nuclease activity in vitro for 41 newly described subgroups. Active systems represent an extensive diversity of protein sequences and guide RNA structures and require diverse protospacer adjacent motifs (PAMs) that collectively expand the known targeting capability of current systems. Several nucleases showed activity levels comparable to or significantly higher than SpCas9, despite being smaller in size. In addition, top systems exhibited low levels of off-target editing in mammalian cells, and PAM-interacting domain engineered chimeras further expanded their targetability. These newly discovered nucleases are attractive enzymes for translation into many applications, including therapeutics.

Compact Cas9d and HEARO enzymes for genome editing discovered from uncultivated microbes

Programmable, RNA-guided nucleases are diverse enzymes that have been repurposed for biotechnological applications. However, to further expand the therapeutic application of these tools there is a need for targetable systems that are small enough to be delivered efficiently. Here, we mined an extensive genome-resolved metagenomics database and identified families of uncharacterized RNA-guided, compact nucleases (between 450 and 1,050 aa). We report that Cas9d, a new CRISPR type II subtype, contains Zinc-finger motifs and high arginine content, features that we also found in nucleases related to HEARO effectors. These enzymes exhibit diverse biochemical characteristics and are broadly targetable. We show that natural Cas9d enzymes are capable of genome editing in mammalian cells with >90% efficiency, and further engineered nickase variants into the smallest base editors active in E. coli and human cells. Their small size, broad targeting potential, and translatability suggest that Cas9d and HEARO systems will enable a variety of genome editing applications.

Novel Type V-A CRISPR Effectors Are Active Nucleases with Expanded Targeting Capabilities

Cas12a enzymes are quickly being adopted for use in a variety of genome-editing applications. These programmable nucleases are part of adaptive microbial immune systems, the natural diversity of which has been largely unexplored. Here, we identified novel families of Type V-A CRISPR nucleases through a large-scale analysis of metagenomes collected from a variety of complex environments, and developed representatives of these systems into gene-editing platforms. The nucleases display extensive protein variation and can be programmed by a single-guide RNA with specific motifs. The majority of these enzymes are part of systems recovered from uncultivated organisms, some of which also encode a divergent Type V effector. Biochemical analysis uncovered unexpected protospacer adjacent motif diversity, indicating that these systems will facilitate a variety of genome-engineering applications. The simplicity of guide sequences and activity in human cell lines suggest utility in gene and cell therapies.

Altered skin flowmotion in hypertensive humans

Essential hypertensive humans exhibit attenuated cutaneous nitric oxide (NO)-dependent vasodilation. Using spectral analysis (fast Fourier transformation) we aimed to characterize the skin flowmotion contained in the laser-Doppler flowmetry recordings during local heating-induced vasodilation before and after concurrent pharmacological inhibition of nitric oxide synthase (NOS) in hypertensive and age-matched normotensive men and women. We hypothesized that hypertensive subjects would have lower total power spectral densities (PSDs), specifically in the frequency intervals associated with intrinsic endothelial and neurogenic control of the microvasculature. Furthermore, we hypothesized that NOS inhibition would attenuate the endothelial frequency interval. Laser-Doppler flowmetry recordings during local heating experiments from 18 hypertensive (MAP: 108±2mmHg) and 18 normotensive (MAP: 88±2mmHg) men and women were analyzed. Within site NO-dependent vasodilation was assessed by perfusion of a non-specific NOS inhibitor (N(G)-nitro-l-arginine methyl ester; l-NAME) through intradermal microdialysis during the heating-induced plateau in skin blood flow. Local heating-induced vasodilation increased total PSD for all frequency intervals (all p<0.001). Hypertensives had a lower total PSD (p=0.03) and absolute neurogenic frequency intervals (p<0.01) compared to the normotensives. When normalized as a percentage of total PSD, hypertensives had reduced neurogenic (p<0.001) and augmented myogenic contributions (p=0.04) to the total spectrum. NOS inhibition decreased total PSD (p<0.001) for both groups, but hypertensives exhibited lower absolute endothelial (p<0.01), neurogenic (p<0.05), and total PSD (p<0.001) frequency intervals compared to normotensives. These data suggest that essential hypertension results in altered neurogenic and NOS-dependent control of skin flowmotion and support the use of spectral analysis as a non-invasive technique to study vasoreactivity.

Validating functional measures of physical ability for aging people with intellectual developmental disability

Unlike the aging population without intellectual and developmental disabilities (IDD), few standardized performance measures exist to assess physical function and risk for adverse outcomes such as nonfatal, unintentional injuries. We modified 3 selected standardized performance tools in the areas of general fitness (2-Minute Walk Test), balance and gait (Performance-Oriented Mobility Assessment I), and functional independence (Modified Barthel Index) for administration with people with IDD. The modified tools were piloted with 30 participants. Results indicated the measures are strongly associated and successfully distinguished between participants with an adverse health event in the previous year. The modified tools have potential to provide clinicians with quantitative measures that track physical performance changes associated with aging in people with IDD.

Patient navigation significantly reduces delays in breast cancer diagnosis in the District of Columbia

BACKGROUND

Patient Navigation (PN) originated in Harlem as an intervention to help poor women overcome access barriers to timely breast cancer treatment. Despite rapid, nationally widespread adoption of PN, empirical evidence on its effectiveness is lacking. In 2005, National Cancer Institute initiated a multicenter PN Research Program (PNRP) to measure PN effectiveness for several cancers. The George Washington Cancer Institute, a project participant, established District of Columbia (DC)-PNRP to determine PN's ability to reduce breast cancer diagnostic time (number of days from abnormal screening to definitive diagnosis).

METHODS

A total of 2,601 women (1,047 navigated; 1,554 concurrent records-based nonnavigated) were examined for breast cancer from 2006 to 2010 at 9 hospitals/clinics in DC. Analyses included only women who reached complete diagnostic resolution. Differences in diagnostic time between navigation groups were tested with ANOVA models including categorical demographic and treatment variables. Log transformations normalized diagnostic time. Geometric means were estimated and compared using Tukey-Kramer P value adjustments.

RESULTS

Average-geometric mean [95% confidence interval (CI)]-diagnostic time (days) was significantly shorter for navigated, 25.1 (21.7, 29.0), than nonnavigated women, 42.1 (35.8, 49.6). Subanalyses revealed significantly shorter average diagnostic time for biopsied navigated women, 26.6 (21.8, 32.5) than biopsied nonnavigated women, 57.5 (46.3, 71.5). Among nonbiopsied women, diagnostic time was shorter for navigated, 27.2 (22.8, 32.4), than nonnavigated women, 34.9 (29.2, 41.7), but not statistically significant.

CONCLUSIONS

Navigated women, especially those requiring biopsy, reached their diagnostic resolution significantly faster than nonnavigated women.

IMPACT

Results support previous findings of PN's positive influence on health care. PN should be a reimbursable expense to assure continuation of PN programs.

Abstract B90: Patient navigation significantly reduces delays in breast cancer diagnosis in the District of Columbia

Background: Delays in follow-up after breast cancer screening may contribute to disparities in breast cancer outcomes. To eliminate breast cancer disparities in Washington, D.C., The GW Cancer Institute established the D.C. Citywide Patient Navigation Research Program (DC-PNRP), which is one of nine national PNRP sites funded by the National Cancer Institute and the American Cancer Society to evaluate the effectiveness of patient navigation. The primary objective of this study is to determine the impact of patient navigation in reducing breast cancer diagnostic time, defined as the number of days from abnormal screening to definitive diagnosis.

Methods: This is a prospective study of 1922 women (728 navigated and 1194 concurrent race-matched records-based non-navigated) examined for breast cancer between 1998 and 2010 at nine hospitals and clinics located in Washington, D.C. Analysis of variance (ANOVA) was used to test for significant differences in diagnostic time between navigated and non-navigated women, while controlling for race/ethnicity (non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic), type of health insurance (private, government, none), and age at abnormal screening (&lt;40, 40–49, 50–59, 60+). Two-way interactions between group and each of the demographic variables race/ethnicity, type of health insurance, and age at abnormal screening were considered. To satisfy model assumptions, diagnostic time was normalized through a log transformation. Geometric means were estimated and compared using a Tukey-Kramer p-value adjustment.

Results: Unadjusted average—geometric mean (95% CI)—diagnostic times (in days) were 23.9 (20.5, 27.8) for navigated and 37.2 (33.0, 41.8) for non-navigated women (p&lt;0.0001). A factorial ANOVA model revealed significant interactions between navigation and both race/ethnicity (p=0.02) and age at abnormal screening (p=0.03) after controlling for type of insurance (p=0.0008). Navigated NHW had a significantly shorter adjusted average diagnostic time, 6.1 (3.5, 10.5) days, than non-navigated NHW, 16.0 (11.5, 22.3) days (p=0.03); and navigated Hispanics had a significantly shorter adjusted average diagnostic time, 26.5 (19.5, 36.0) days, than non-navigated Hispanics, 57.2 (44.8, 73.1) days (p=0.0005). While navigated NHB had a shorter adjusted average diagnostic time, 26.2 (21.5, 31.9) days, than non-navigated NHB, 34.3 (28.4, 41.4) days, this decrease was not statistically significant (p=0.32). Navigation reduced the diagnostic time for women of all ages, but this decrease was statistically significant only for women aged 60+ years (p&lt;0.0001). Navigated women younger than 40 or 60+ had significantly shorter adjusted average diagnostic times than those aged 50–59 (p=0.03 for each). Adjusted average diagnostic times (in days) by age group were 11.2 (7.7, 16.3) for navigated and 22.8 (14.9, 35.0) for non-navigated women &lt;40; 21.6 (15.9, 29.2) for navigated and 33.7 (27.4, 41.4) for non-navigated women 40–49; 23.8 (17.0, 33.5) for navigated and 35.5 (28.4, 44.4) for non-navigated women 50–59; 11.9 (8.4, 16.9) for navigated and 36.2 (28.4, 46.2) for non-navigated women 60+.

Conclusions: The time required for navigated women to reach a definitive diagnosis following an abnormal screening was significantly shorter as compared to non-navigated women. While navigation was effective overall, the program proved to be more helpful for Hispanics and NHW than for NHB, especially among women aged 60+ years. Barriers preventing a rapid diagnostic resolution for NHB need to be explored further.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B90.

Having health insurance does not eliminate race/ethnicity-associated delays in breast cancer diagnosis in the District of Columbia

BACKGROUND

Delays in follow-up after breast cancer screening contribute to disparities in breast cancer outcomes. The objective of this research was to determine the impact of race/ethnicity and health insurance on diagnostic time, defined as number of days from suspicious finding to diagnostic resolution.

METHODS

This retrospective cohort study of 1538 women examined for breast abnormalities between 1998-2010 at 6 hospitals/clinics in the District of Columbia measured mean diagnostic times between non-Hispanic whites (NHWs), non-Hispanic blacks (NHBs), and Hispanics with private, government, or no health insurance by using a full-factorial ANOVA model.

RESULTS

Respective average--geometric mean (95% CI)--diagnostic times (in days) for NHWs, NHBs, and Hispanics were 16 (12, 21), 27 (23, 33), and 51 (35, 76) among privately insured; 12 (7, 19), 39 (32, 48), and 71 (48, 105) among government insured; 45 (17, 120), 60 (39, 92), and 67 (56, 79) among uninsured. Government insured NHWs had significantly shorter diagnostic times than government insured NHBs (P = .0003) and Hispanics (P < .0001). Privately insured NHWs had significantly shorter diagnostic times than privately insured NHBs (P = .03) and Hispanics (P < .0001). Privately insured NHBs had significantly shorter diagnostic times than uninsured NHBs (P = .03).

CONCLUSIONS

Insured minorities waited >2 times longer to reach their diagnostic resolution than insured NHWs. Having private health insurance increased the speed of diagnostic resolution in NHBs; however, their diagnostic time remained significantly longer than for privately insured NHWs. These results suggest diagnostic delays in minorities are more likely caused by other barriers associated with race/ethnicity than by insurance status.

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists.

Abstract PR-10: Impact of race, ethnicity and health insurance on delays in breast cancer diagnosis in the District of Columbia

Background: Delays in follow-up after breast cancer screening are thought to contribute to disparities in breast cancer outcomes. The primary objective of this study is to determine the impact of race/ethnicity and type of health insurance on the diagnostic delay time, defined as the number of days from abnormal screening to definitive diagnosis.

Methods: This is a retrospective study of 976 women examined for breast cancer between 1998 and 2009 at six hospitals and clinics located in the District of Columbia. We used a full-factorial ANOVA model to test for significant differences in diagnostic delay time among non-Hispanic white (NHW), non-Hispanic black (NHB), and Hispanic women with private, government, or no health insurance. A log transformation was taken on the diagnostic delay time to normalize our data, and geometric means were estimated and compared.

Results: The average geometric mean (95% CI) diagnostic delay times were as follows: among those with private insurance, 15.9 (12.2,20.6) days for NHW, 27.0 (22.4,32.6) days for NHB, and 51.4 (34.8,76.0) days for Hispanic women; among those with government insurance, 11.9 (7.3,19.3) days for NHW, 39.5 (32.2,48.6) days for NHB, and 71.6 (47.8,107.1) days for Hispanic women; and among those without insurance, 44.5 (16.4,120.6) days for NHW, 59.7 (38.8,91.8) days for NHB, and 66.4 (55.8,79.1) days for Hispanic women. In fitting a full-factorial ANOVA model, we found that NHW women with government insurance had a significantly shorter delay in diagnosis than NHB (p=0.0003) and Hispanic (p&lt;0.0001) women with government insurance. We also found that NHW women with private insurance had a significantly shorter delay in diagnosis than NHB (p=0.03) and Hispanic (p&lt;0.0001) women with private insurance. However, there were no significant differences within the uninsured women (p&gt;0.05). Finally, we found that NHB women with private insurance had a significantly shorter delay in diagnosis than uninsured NHB women (p=0.03).

Conclusions: NHB and Hispanic women with government or private insurance waited more than twice as long to reach their definitive diagnosis than NHW women with government or private insurance. Uninsured NHB women waited more than twice as long to reach their definitive diagnosis than NHB women with private insurance. Having private health insurance markedly increased the speed of diagnostic resolution in NHB women; however, the speed of diagnostic resolution remained significantly longer for NHB women with private insurance than for NHW women with private insurance. These results suggest that while both insurance and race/ethnicity affect diagnostic resolution, health insurance may not be the primary barrier to optimal diagnostic resolution in NHB women. It will be important to determine what other factors serve as the primary barriers, as well as if these delays affect the final breast cancer outcome for the patients.

Funding Mechanism: Grant Number 1 U01 CA116937; Patient Navigation Research Program (PNRP), Center for Research on Cancer Health Disparities (CRCHD), National Cancer Institute (NCI).

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):PR-10.

Abstract B90: The District of Columbia citywide Patient Navigation Research Program (DC-PNRP): Preliminary descriptive findings

Introduction: Minority breast cancer mortality rates in Washington, DC are among the Nation's highest. To address these disparities we instituted the DC Citywide Patient Navigation Research Program (DC-PNRP) - an inter-institutional collaboration that is one of 9 National PNRP sites funded by NCI/ACS to evaluate the effectiveness of patient navigation in reducing time from suspicious finding to diagnostic resolution and time from resolution to treatment initiation.

Study Procedures: A total of 1024 women, mostly minorities, have been enrolled from 8 recruitment sites at the point of suspicious finding. Utilizing a non-randomized design, 1240 concurrent, medical records-based controls were identified from 6 sites for comparison. Subject recruitment ended March 31,2010, but data collection continues on those women already enrolled. A unique framework of “network navigation” emerged whereby services were integrated across a city-wide network of unaffiliated healthcare sites. Navigators from a broad partnership of clinical and community sites were trained to work collaboratively within a city-wide network to enroll patients in the study and assure each receives timely, quality care. This “integrative navigation”model is collecting data addressing not only structural barriers to access to care (i.e., inadequate insurance, lack of transportation, etc.), but also psychosocial barriers (i.e., fear, medical mistrust, acculturation, etc.). Frequent trainings, efforts that promote increased communication between navigators, and sharing of information about community resources were implemented to enhance care coordination and to assure appropriate referral strategies between community outreach, screening, and treatment sites.

Results and Conclusion: Among controls, 7.66% were non-Hispanic whites (NHW), 35.24% were non-Hispanic blacks (NHB), 30.65% were Hispanic, and 26.45% were of other or unknown race/ethnicity. The corresponding percentages for navigated patients were 7.03%, 48.93%, 29.88%, and 14.16% indicating larger numbers of NHB and fewer with other/unknown race/ethnicity among the navigated patients. When examining age of subjects grouped by &lt;40 years, 40-49 years, 50-59 years, 60-69 years, 70-79 years, and &gt;=80 years, respective proportions among controls were 7.10%, 37.98,28.15,16.29, 6.61, and 3.87%, while the distribution for navigated patients was: 20.70%, 32.03,24.41,14.06,5.57, and 3.22%, respectively, suggesting that navigated patients were slightly younger than controls. Household income level was generally unavailable for controls and for 35.54% of navigated patients. Proportions of navigated patients falling into the income categories &lt;$10,000, $10-19,999, $20-29,999, $30-39,999, $40-49,999, and &gt;=$50,000 are 14.06%, 13.38,9.38,9.18,4.59, and 13.87%, respectively, indicating fairly substantial numbers of low income patients. Among controls, 29.27% indicated they had no form of health insurance. The proportion was similar for navigated patients at 33.98%. Our data indicate we have comparable groups based on demographic attributes of navigated and control patients for our future analyses.

Funding Mechanism: Grant Number 1 U01 CA116937; Patient Navigation Research Program (PNRP), Center for Research on Cancer Health Disparities (CRCHD), National Cancer Institute (NCI).

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B90.

Abstract 862: Network patient navigation: An integrative, longitudinal model to reduce breast cancer disparities

Introduction: Minority breast cancer mortality rates in Washington, DC are among the nation's highest. To address disparities we instituted the DC Citywide Patient Navigation Research Program (DC-PNRP) - an inter-institutional collaboration that is one of 9 National PNRP sites funded by NCI/ACS to evaluate the effectiveness of patient navigation in reducing barriers to obtaining health care while also addressing psychosocial factors.

Study Procedures: More than 1000 minority women have been enrolled from 7 recruitment sites at the point of suspicious finding to investigate whether patient navigation decreases time from suspicious breast finding to diagnostic resolution and time from diagnosis to treatment initiation. Utilizing a non-randomized design, concurrent, medical records-based controls have been identified. Data collection will extend through March 2010. A unique framework of “network navigation” emerged whereby services were integrated across a city-wide network of unaffiliated healthcare sites. Navigators from a broad partnership of clinical and community sites were trained to work collaboratively within a city-wide network to enroll patients in the study and assure each patient receives timely, quality care. This “integrative navigation” model is collecting data addressing not only structural barriers to access to care (i.e., inadequate insurance, lack of transportation, etc.), but also psychosocial barriers (i.e., fear, medical mistrust, acculturation, etc.). Frequent trainings, efforts that promote increased communication between navigators, and sharing of information about community resources were implemented to enhance care coordination and to assure appropriate referral strategies between community outreach, screening, and treatment sites.

Results and Conclusion: Implementation of DC-PNRP led us to broaden the original treatment-oriented navigation model to create a “Longitudinal Navigation” paradigm that follows the patient from outreach through survivorship. Data will be shown describing how this model addresses barriers to access and the underlying fragmentation of services that exist in DC for low-income uninsured or under-insured women. Data on the types and distribution of barriers will also be presented. This city-wide program serves as model for inter-institutional cooperation to improve health care access, particularly for the underserved.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 862.

Abstract 865: Impact of race and health insurance on delays in breast cancer diagnosis and treatment in the District of Columbia

Background: Delays in follow-up after breast cancer screening are thought to contribute to disparities in breast cancer outcomes. The primary objective of this study is to determine the impact of race as well as health insurance status on the diagnostic delay time, defined as the number of days from abnormal screening to definitive diagnosis. In addition, we analyze the effects of race and health insurance status on the treatment delay time, defined as the number of days from definitive breast cancer diagnosis to treatment initiation.

Methods: This is a retrospective study of 695 women examined for breast cancer between 1997 and 2009 at seven hospitals and clinics located in the District of Columbia. The outcomes of interest were the diagnostic delay time and the treatment delay time. We used full-factorial and main-effects ANOVA models to test for significant differences in these outcomes between African-American and white women with and without some type of health insurance.

Results: The mean diagnostic delay time was 37 days for insured white women, 76 days for uninsured white women, 75 days for insured African-American women, and 73 days for uninsured African-American women. In fitting a full-factorial ANOVA model, we found that insured white women had a significantly shorter delay in diagnosis than insured African-American women (p=0.0001) as well as uninsured white women (p=0.0007). Furthermore, a main-effects ANOVA model showed that after controlling for insurance status, African-American women had a mean treatment delay time of 45 days, which was significantly longer than the mean treatment delay time of only 17 days for white women (p&lt;0.0001). Insurance status, however, had no significant effect on the treatment delay time after controlling for race (p=0.72).

Conclusions: Insured African-American women and uninsured white women waited more than twice as long to reach their definitive diagnosis than insured white women. African-American women also waited more than three times as long as white women for treatment initiation following definitive diagnosis. Lack of health insurance markedly decreased the speed of diagnostic resolution in white women, but having health insurance did not increase the speed of diagnostic resolution in African-American women. These results suggest that lack of health insurance may not be the primary barrier to optimal diagnostic resolution and treatment initiation in African-American women. It will be important to determine what other factors serve as the primary barriers, as well as if these delays affect the final breast cancer outcome for the patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 865.

Guidelines for hypertension treatment: applications for primary care practice--a review of the JNC VI report

The Joint National Committee's report on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure was released in November 1997. With its release, an increased emphasis on "treating the patient, not just the number" has taken place. The report provides a comprehensive review of recent clinical evidence that helps guide clinical decision making in the care of the hypertensive patient. A new disease classification system entitled "risk stratification" is introduced and takes into account comorbid conditions that are present for many hypertensive individuals. This risk stratification is then linked to treatment strategies and provides a concise decision analysis framework to aid in clinical decision making. Community-based prevention strategies are also highlighted and should raise the awareness of clinicians to adopt these recommendations and integrate them more aggressively into daily practice. Increased emphasis on patient compliance to improve overall hypertension control rates is also presented. Maximum efficacy through once-daily dosing and fixed-dose combinations are reviewed in the report. The JNC report is a comprehensive resource for clinicians in primary care practice. Its evidenced-based approach is a wonderful teaching tool for those clinicians who also serve as clinical educators in primary care.

Bioavailability and pharmacokinetics of microencapsulated 1,3-dichloropropene in rats

The potential oral toxicity of 1,3-dichloropropene (1,3-D) has been evaluated in a number of dietary toxicity studies. The relatively high vapor pressure of 1,3-D, its short half-life in drinking water, and its reactivity with constituents of feed necessitated the use of a microencapsulated formulation (starch-sucrose shell) of 1,3-D in these studies. The bioavailability of ingested microencapsulated 1,3-D was determined by characterizing and comparing the kinetics of 1,3-D in the blood of female F344 rats coadministered microencapsulated 1,3-D and neat 13C-1,3-D (25 mg/kg each) via gavage. Blood concentrations of total or cis- and trans-isomers of 1,3-D in treated rats were determined using gas chromatography-mass spectroscopy (GC-MS) or in situ membrane extraction MS. Urine was also collected and analyzed by GC-MS for the presence of the mercapturate excretion product of 1,3-D [N-acetyl-S-(3-chloropropenyl-2)-L-cysteine; 1,3-DMA]. Blood levels of 1,3-D and 13C-1,3-D displayed similar kinetics, peaking within 10 min of dosing followed by a rapid biphasic elimination. Higher peak blood levels and greater blood curve areas (AUC) were attained for trans- than cis-1,3-D and 13C-1,3-D and greater amounts of cis- than trans-1,3-DMA and 13C-1,3-DMA were excreted in the urine consistent with the known rapid and disproportionate glutathione conjugation of the cis-isomer in the gastric mucosa. Slightly higher cis-1,3-D than cis-13C-1,3-D blood levels and AUCs were also consistently noted while the reverse was true for urinary excretion of cis-13C-1,3-DMA and cis-1,3-DMA suggesting that 1,3-D derived from microencapsulated test material may be absorbed and/or metabolized in the stomach mucosa at a slightly slower rate than that from neat material. The latter, however, would be of no consequence during the administration of 1,3-D to animals via their diets as competing test materials would not be present and 1,3-D blood kinetics were unaffected. Overall, the results of this study demonstrate the ready bioavailability of microencapsulated 1,3-D and rapid elimination of 1,3-D from the blood of rats.

Reconstitution of protein kinase A regulation of the rat prolactin promoter in HeLa nonpituitary cells: identification of both GHF-1/Pit-1-dependent and -independent mechanisms

Expression of the rat PRL (rPRL) gene is highly restricted to pituitary lactotroph cells and is induced by the cAMP-dependent protein kinase A (PKA) pathway. Current data indicate that this PKA effect requires at least one of the redundant pituitary-specific elements of the proximal rPRL promoter, suggesting the involvement of the pituitary-specific transcription factor, GHF-1/Pit-1. To directly determine whether GHF-1 is necessary and sufficient to mediate the PKA activation of the rPRL promoter, we established a cotransfection reconstitution assay whereby the activity of an intact and site-specific mutants of the (-425 to +73) rPRL promoter-luciferase reporter gene was reconstituted by cotransfecting expression vectors encoding for either the PKA beta catalytic subunit, GHF-1, or both, into HeLa nonpituitary cells. Cotransfection of PKA beta alone significantly stimulated rPRL promoter activity in HeLa cells in a GHF-1-independent manner, and this PKA beta effect was mapped to the most proximal GHF-1 site [footprint (FP) I; -67/-36]. Site-specific alterations of either FP II (-130/-120), or of the basal transcription element (BTE; -112/-80), did not significantly affect the PKA beta response. As expected, the transactivation effect of cotransfected GHF-1 mapped to the GHF-1/Pit-1 binding sites, FP I and/or FP III, of the rPRL promoter. Finally, cotransfection of PKA beta and GHF-1 resulted in a marked synergistic response of the rPRL promoter, and this response also localized to the FP I site. These data confirm not only that GHF-1/Pit-1 and the FP I site are involved in mediating the PKA response, but also imply that a distinct and possibly ubiquitous factor is involved by binding to FP I and functionally interacting with GHF-1 to modulate PKA beta regulation of the rPRL promoter.

Relative exposure of children to lead from dust and drinking water

The Blackpool, Wyre and Fylde Health Authority, in the North West of England, could be described as a "low-level lead exposure area." Primary sources of lead exposure are atmospheric fallout (both indoors and outdoors) and potable water consumption. Deciduous teeth were collected from children living in this area as were water samples and outdoor dust samples. Both total lead concentrations and 206Pb:207Pb ratios were determined for a defined subset of teeth. Significant differences in the total lead concentrations were found for teeth collected from children resident in different targeted areas (i.e., Blackpool, Fleetwood, and Garstang). No significant differences were found between the total lead concentrations or the 206Pb:207Pb ratios from dust and water samples in these areas. Examination of the 206Pb:207Pb ratios for dust, water, and teeth obtained from each area separately revealed differing patterns of exposure to lead. Determination of 206Pb:207Pb ratios, in addition to total lead concentrations, enabled the differences in sources of exposure to be identified in these communities. The authors conclude that isotopic analyses are an important aspect of community survey work, and these analyses can be helpful in accurately targeting intervention strategies aimed at reducing exposure to lead.

Symptomatology of children in contact with sea water contaminated with sewage

STUDY OBJECTIVE

The aim was to determine whether or not there was a measurable risk of ill health associated with contact with sea water for children between the ages of 6 and 11 years old.

DESIGN AND SETTING

This was a prospective survey carried out on Blackpool beach. Parents of children between the ages of 6 and 11 years were interviewed over a seven week period during July, August, and September, 1990. Respondents were followed up 10-14 d after the original interview by either telephone or post. Water samples were collected on each day of the survey.

PARTICIPANTS

939 interviews with parents or guardians were completed on the beach; 857 (91.9%) of these persons agreed to a follow up interview. The results of this study are based on 703 cases of matched data, of good quality, collected for each child on the beach and during a follow up interview.

MAIN RESULTS

Non-compliance with the European Community microbiological imperative standards for recreational waters at Blackpool Tower and South Pier sampling sites, respectively, ranged between: 6% and 7% for total coliforms; 13% and 25% for faecal coliforms; 69% and 80% for faecal streptococci (Guide standard); 50% and 67% for salmonellae and 73% and 88% for enteroviruses. There was a significant overall increase in the mean number of symptoms reported for each child (p < 0.001). However, the prevalence of certain symptoms increased significantly only in those children who had been in contact with the water on the day of the beach interview. These symptoms included vomiting (p < 0.0009), diarrhoea (p < 0.0001), itchy skin (p < 0.0009), fever (p < 0.0013), lack of energy (p < 0.0007), and loss of appetite (p < 0.0227). None of the other variables investigated could account for the significant increase in the reported symptom experience of those children in contact with sea water contaminated with sewage.

CONCLUSIONS

Children who come into contact with contaminated sea water are likely to develop symptoms as a result.

Protein factors in thyrotropic tumor nuclear extracts bind to a region of the mouse thyrotropin beta-subunit promoter essential for expression in thyrotropes

The beta-subunit gene of TSH is specifically expressed in thyrotrope cells of the anterior pituitary gland. To define the particular TSH beta-subunit gene sequences responsible for tissue-specific expression, TSH beta promoter fragments were assessed for promoter activity by gene transfer into TSH-expressing thyrotropic tumor cells (TtT-97). Previous studies have shown that the murine TSH beta gene promoter was more efficiently used in TtT-97 cells compared to other pituitary-derived cells or nonpituitary fibroblasts and that a 191-basepair DNA sequence of the 5' flanking region between -271 and -80 was sufficient for maximal promoter activity in thyrotropes. Further deletional analysis within this region has localized the area responsible for expression in thyrotropes to a 37-basepair region between -117 and -80 up-stream of the major transcriptional initiation site. DNase-I protection assays demonstrated that this functionally defined 5' flanking area, in addition to the adjacent sequences immediately up-stream and down-stream, interacts with protein factors present in nuclear extracts from TtT-97 tumor cells. When fused to a heterologous promoter, fragments derived from the region between -271 and -80 exhibited cell-specific activity, although this was not conferred solely by the TSH beta promoter fragment from -117 to -80. Heterologous promoter activity was further stimulated when fragments containing the areas from -271 or -201 to -77 were used, suggesting combinatorial cis interactions between these regions of the TSH beta promoter. DNase-I protection studies suggest that there are multiple protein-binding domains in the mouse TSH beta 5' flanking sequence. Only the more proximal domains, which encompass important promoter elements, appear to be required for efficient expression in thyrotropes, whereas other more up-stream sites of protein interaction may be involved in regulatory aspects of TSH beta gene expression.

Activation of the murine thyrotropin beta-subunit promoter by GH4 rat pituitary cell-free extracts

Expression of the TSH beta subunit gene is restricted to the thyrotroph cells of the anterior pituitary. Previously we identified several AT-rich DNA elements within the murine (m) TSH beta 5'-flanking region, denoted as D1 (-253 to -227), P4 (-142 to -131), P3 (-126 to -112), P2 (-106 to -98), and P1 (-76 to -68) which bind thyrotroph-specific factor(s). These sites are related to, but distinct from GHF-1 and LSF-1 binding sites, which restrict GH and PRL gene expression to pituitary somatotrophs and lactotrophs, respectively. To determine whether different pituitary cell types contain related factors capable of activating the mTSH beta promoter, cell-free transcription studies were performed using extracts from GH4 rat pituitary somatomammotroph cells. AI-through the endogenous mTSH beta gene is not expressed in GH4 cells, in vitro transcription of the mTSH beta promoter, normalized to the Rous sarcoma virus internal control, revealed faithful transcription initiation from the authentic mTSH beta CAP sites in GH4 but not in HeLa cell extracts. Cell-free transcription analysis of mTSH beta 5'-deletion mutants revealed consistent promoter activity with deletion to position -46 but complete loss of activity when deleted to position -9. To better define the specific factors in pituitary somatomammotrophs which interact with and activate the mTSH beta promoter, DNase I protection and gel-shift studies were performed using extracts from GC rat pituitary somatomammotroph cells and DNA affinity-purified lactotroph-specific transcription factor, LSF-1, required for rat PRL promoter activity, and purified from GC cells. These cells contain a factor(s) which binds to thyrotroph-specific elements of the mTSH beta promoter. These studies also show that LSF-1 binds the D1 and proximal thyrotroph-specific elements of the mTSH beta promoter and is capable of reconstituting the trans-activation of the mTSH beta promoter in HeLa nonpituitary cell extracts in vitro. Conversely, nuclear factors present in TtT-97 murine thyrotrophs bind the proximal lactotroph-specific elements on the rPRL promoter. This in vitro transcription assay provides a means to biochemically dissect the trans-activation of the mTSH beta promoter and to determine the functional overlap of distinct pituitary cell-specific factors in regulating GH, PRL, and TSH beta gene expression.

Identification of thyrotroph-specific factors and cis-acting sequences of the murine thyrotropin beta subunit gene

Pituitary thyrotroph cells specialize in the synthesis of TSH, and thus represent a model to study cell-specific gene expression. We have used the murine TSH beta (mTSH beta) gene promoter and TSH-producing and nonproducing transplantable tumors derived from murine thyrotroph cells, referred to as TtT-97 and MGH 101A, respectively, to identify nuclear factors which selectively interact with the mTSH beta gene. DNase I protection analyses demonstrate that factors present in TtT-97 nuclear extracts bind with high affinity to five separate sites in the TSH beta promoter region, denoted as distal D1 (-253 to -227) and proximal, P1 (-76 to -68), P2 (-106 to -98), P3 (-126 to -112), and P4 (-142 to -131) footprints. By contrast, non-TSH beta expressing thyrotroph cell nuclear extracts and L-cell nonpituitary cell extracts did not appear to footprint the D1 site; whereas the nonpituitary nuclear extracts revealed minimal DNase I protection in the P1-P4 regions. These data show that the distal D1 site is thyrotroph specific and contains a 6 base pair direct repeat sequence (5'-AGATAT-3'). Factor occupancy of the D1 site is protein dependent, occurs rapidly (less than 15 sec), is destabilized by 170 mM KCl, and results in an associated DNase I hypersensitive region. A double-stranded oligonucleotide spanning the D1 footprint competes only the distal factor binding region. Transfection of plasmid constructs containing progressive 5'-deletions of the mTSH beta promoter linked to the reporter gene luciferase into primary TtT-97 cells demonstrate a marked decrease in activity between the regions -270 and -79, which contains the D1 region.(ABSTRACT TRUNCATED AT 250 WORDS)