In vitro antibacterial efficacy of cetylpyridinium chloride-containing mouthwashes

OBJECTIVE

The objective of this study was to examine the ability of three CPC-containing mouthwashes to kill planktonic bacteria in an in vitro short-exposure assay.

METHODS

This blind study was conducted on two common oral bacterial species: Aggregatibacter (Actinobacillus) actinomycetemcomitans and Streptococcus mutans. The following mouthwashes were tested: two containing 0.075% CPC and 0.05% NaF in an alcohol-free base, and one containing 0.075% CPC and 0.05% NaF plus 6% alcohol. Additionally, a 0.05% NaF-only mouthwash was included as a negative control. Bacteria were exposed to one of the test mouthwashes for 30 seconds and then washed thoroughly, serially diluted, and plated on appropriate media to determine viable bacterial counts. Viable counts were converted to a log reduction in colony forming units (CFUs) relative to the negative control.

RESULTS

All three test mouthwashes included in this study gave a statistically significant reduction of > 3 log CFUs relative to samples treated with the negative control.

CONCLUSION

All three experimental 0.075% CPC mouthwash formulas gave a > 99.9% reduction in viable bacteria of both species following 30 seconds of treatment.

The antibacterial and antiplaque effectiveness of mouthwashes containing cetylpyridinium chloride with and without alcohol in improving gingival health

This article briefly discusses the antibacterial action ofcetylpyridinium chloride (CPC) and its efficacy in the removal of bacterial plaque as an adjunct to the mechanical cleaning of tooth surfaces. It reviews new studies on the effectiveness of mouthwash formulations containing CPC against two common oral bacteria species and in disrupting plaque biofilms. Finally, this article reviews three clinical studies which support that the daily use of mouthwashes containing 0.075% CPC, with and without alcohol, represents a valuable complement to daily mechanical plaque control.

Clinical efficacy of a triclosan/copolymer/NaF dentifrice and a commercially available breath-freshening dentifrice on hydrogen sulfide-forming bacteria

OBJECTIVE

The objective of this randomized, cross-over clinical study was to compare the 4-h and overnight effects of a triclosan/copolymer/fluoride (TCF-AF) dentifrice and a commercially available breath freshening (CBF) dentifrice containing fluoride for their ability to control H(2)S-forming bacteria.

METHODS

Following a 1 week washout period of brushing with a regular fluoride dentifrice, subjects reported to the clinical site without performing oral hygiene, eating or drinking in preparation for baseline saliva sampling. After providing a baseline saliva sample, subjects were randomly assigned a test dentifrice and instructed to brush their teeth for 1 min, twice a day for 1 week. On the morning of the eighth day, subjects returned to the test site having refrained from oral hygiene, eating and drinking for overnight sampling. Subjects then brushed for 1 min with the assigned dentifrice, and returned for 2 and 4 h postbrushing evaluations. Following a second 1 week washout, subjects repeated the same regimen, but now using the other dentifrice. Oral micro-flora samples were collected by subjects rinsing with 10 ml of sterile water for 10 s. Each collected sample was serially diluted and plated in duplicate onto lead acetate agar. After incubating for 72 h, dark colonies were counted, expressed as log colony-forming units/ml, and reductions from baseline were calculated.

RESULTS

Compared with baseline, the TCF-AF dentifrice reduced H2S-forming bacteria 0.82, 0.80 and 0.22 log units at the 2 and 4 h and overnight time points compared with 0.60, 0.43 and 0.07 log units for the CBF dentifrice. The TCFAF dentifrice was statistically significantly better (P < 0.05) than the CBF dentifrice at 4 h and overnight after brushing the teeth.

CONCLUSION

The results of this randomized study indicate that the TCF-AF dentifrice is effective in controlling H2S-producing bacteria.

Improving osteoporosis management in patients with fractures

A history of fracture is an independent risk factor for future fractures, but patients who have sustained a fracture are rarely evaluated for osteoporosis (OP). The objective of this study was to determine if a simple intervention in a general orthopedic clinic would lead to more fracture patients receiving evaluation and treatment for OP. Patients with a history of fracture visiting a weekly orthopedic clinic during a 6-month intervention period were educated about OP, and a bone mineral density (BMD) test was offered. The number of BMD tests performed and other OP-specific actions taken as a result of the intervention were compared with a 6-month pre-intervention period. The prevalence of OP in those who underwent BMD testing was examined. In the pre-intervention period, only 12.7% (16 of 126) had a BMD test as compared with 62.5% of the 136 intervention-period subjects (odds ratio [OR] 11.5, 95% confidence interval [CI] 6.1, 21.4). Based on BMD test results, 11.9% of the pre-intervention patients, and 41.9% of the intervention patients received OP-specific recommendations (OR 5.3, 95% CI 2.8, 10.1). The intervention led to more patients being treated for low bone mass (9.5% vs 23.5%); OR 2.9, 95% CI 1.4, 5.9. Low bone mass was common among all types of fracture patients: 20% had osteoporosis and 41%, osteopenia. BMD testing in patients with fractures should identify those at risk for future fractures, leading to appropriate treatment.

Effect of a triclosan/PVM/MA copolymer/fluoride dentifrice on volatile sulfur compounds in vitro

OBJECTIVE

The objective of the investigation was to document the in vitro efficacy of a triclosan/PVM/MA copolymer/fluoride (TCF) dentifrice against the formation of volatile sulfur compounds (VSC) as well as the growth of H2S-producing bacteria. Clinical studies using organoleptic judges, gas chromatography, or a portable sulfide monitor have generally been employed in the assessment of treatments for the control of oral malodor. However, these studies are not appropriate for screening purposes because of the expense and time required.

METHODS

An in vitro method was developed for the purpose of screening new compounds, agents or formulations for their ability to control VSC formation and for determining bio-equivalence of efficacy when implementing changes in existing formulations. The method combines basic microbiological methods, dynamic flow cell techniques and head space analysis. The in vitro VSC method was validated by comparing the efficacy of two dentifrices containing TCF with a control fluoride dentifrice as the TCF products have been clinically proven to control oral malodor.

RESULTS

In the validation studies, the TCF-containing dentifrices were significantly better (P < 0.05) than the control dentifrice in inhibiting VSC formation and reducing H(2)S-producing bacteria. For example, when compared with baseline, the TCF dentifrices reduced VSC formation between 42 and 49% compared with the control dentifrice which reduced VSC formation 3%. There was no significant difference (P > 0.05) between the two TCF dentifrice formulations.

CONCLUSION

Using an in vitro breath VSC model, it has been demonstrated that two variants of a dentifrice containing triclosan, PVM/MA copolymer and fluoride have efficacy that is significantly better than a control fluoridated dentifrice and that there is no significant difference between the triclosan/PVM/MA copolymer/fluoride dentifrice variants.

Clinical comparison of a new manual toothbrush on the level of hydrogen-sulfide-forming bacteria on the tongue

The objective of this randomized, crossover study was to compare the effectiveness of a newly designed manual toothbrush (Colgate 360 degrees) to two commercially available manual toothbrushes (Oral-B Indicator and Oral-B CrossAction) and a battery-powered toothbrush (Crest SpinBrush PRO) for their ability to reduce hydrogen-sulfide-forming bacteria on the tongue. After a washout period, subjects arrived at the clinical site for baseline sampling without performing dental hygiene, eating, or drinking. Subjects sampled the left side of their tongue with a cotton swab. Subjects brushed for 1 minute with the assigned test toothbrush and regular fluoride toothpaste. Those using the Colgate 360 degrees toothbrush were instructed to clean their tongue with the implement on the back of the brush head for 10 seconds. After 2 hours, the subjects returned to the clinical site having refrained from dental hygiene, eating, and drinking for posttreatment sampling, this time sampling the right side of their tongue. After a minimum 2-day washout period, subjects repeated the same regimen using the other toothbrushes. Collected tongue samples were dispersed in sterile water, serially diluted in sterile phosphate-buffered saline, and plated in duplicate onto lead acetate agar. When plated on this medium, bacteria that produce hydrogen sulfide appear as dark-pigmented colonies. After 72 hours of incubation, the dark colonies were counted, expressed as log colony-forming units/mL, and reduction from baseline was calculated. Thirty-one adult men and women completed the clinical study. There was no significant difference between baseline hydrogen-sulfide-forming bacteria levels. Posttreatment, the log reduction of bacteria was 0.80, 0.41, 0.33, and 0.44 for the Colgate 360 degrees, Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction, respectively. Statistical analysis indicated that the Colgate 360 toothbrush was statistically significantly better (P < .05) than the 3 commercial toothbrushes in reducing the levels of hydrogen-sulfide-forming bacteria on the tongue.

Clinical efficacy of Colgate 360 degrees and three commercially available toothbrushes on the removal of desquamated epithelial cells

A clinical study was done to evaluate the performance of four toothbrushes on the removal of desquamated epithelial cells after brushing according to the manufacturers' instructions for use. This randomized, crossover-design clinical study compared a new manual toothbrush (Colgate 360 degrees) to two commercially available manual toothbrushes (Oral-B CrossAction and Oral-B Indicator) and a commercially available battery-powered toothbrush (Crest SpinBrush PRO). Adult men and women subjects reported to the clinical facility after a 1-week "washout" period of brushing with a regular fluoride dentifrice and a soft-bristled toothbrush. Participants reported having refrained from oral hygiene procedures, eating, and drinking that morning. After providing a baseline rinse sample, subjects brushed their teeth for 1 minute with their assigned toothbrush and a commercially available fluoride toothpaste, then returned 30 minutes later to provide postuse rinse samples. Subjects refrained from dental hygiene, eating, and drinking during the 30-minute evaluation period. To provide the samples, subjects rinsed with 10 mL of sterile phosphate-buffered saline solution for 10 seconds. Each collected sample was centrifuged, resuspended, and run in a colorimetric assay to determine the level of desquamated epithelial cells found in the rinse as measured by the absorbance at 570 nm. Twenty adults completed the study. At baseline, the mean levels of desquamated epithelial cells for the 4 treatments were 0.70+/-0.27, 0.63+/-0.20, 0.69+/-0.30, and 0.62+/-0.31 for the Colgate 360 degrees, Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction, respectively. Posttreatment, the mean levels of epithelial cells were 0.19, 0.38, 0.42, and 0.34, respectively. All of the treatments provided a statistically significant reduction compared to their respective baseline. In addition, the Colgate 360 degrees toothbrush was statistically significantly better than the other three toothbrushes in reducing desquamated epithelial cells. Therefore, the results of this randomized, crossover clinical study indicate that the newly designed Colgate 360 degrees manual toothbrush, with a tongue-cleaning implement on the back of the brush head, was statistically significantly more effective than the Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction toothbrushes in removing desquamated epithelial cells.

Clinical comparison of a new manual toothbrush on breath volatile sulfur compounds

The objective of this randomized, crossover study was to compare the effectiveness of a newly designed manual toothbrush (Colgate 360 degrees) to two commercially available manual toothbrushes (Oral-B Indicator and Oral-B CrossAction) and a battery-powered toothbrush (Crest SpinBrush PRO) for their ability to reduce overnight volatile sulfur compounds (VSC) associated with oral malodor. The study followed a four-period crossover design. Following a washout period, prospective subjects arrived at the testing facility without eating, drinking, or performing oral hygiene for baseline evaluation of breath VSC levels. For each phase of the study, subjects were given one of the test tooth-brushes and a tube of regular toothpaste to take home, and they were instructed to brush their teeth in their customary manner for 1 minute. When using the Colgate 360 degrees toothbrush, subjects were instructed to clean their tongue with the implement on the back of the brush head for 10 seconds. The following morning, subjects reported to the testing facility, again without performing oral hygiene, eating, or drinking, for the overnight evaluation. After a minimum 2-day washout period, subjects repeated the same regimen using the other toothbrushes. The levels of breath VSC were evaluated instrumentally using a gas chromatograph equipped with a flame photometric detector. Measurements were taken in duplicate and then averaged. The levels of VSC were expressed as parts per billion (ppb) in mouth air. Sixteen men and women completed the study. At baseline, the mean levels of VSC in mouth air for the 4 toothbrushes were 719.8 ppb+/-318.4 ppb, 592.8 ppb+/-264.6 ppb, 673.8 ppb+/-405.9 ppb, and 656.2 ppb+/-310.2 ppb for the Colgate 360 degrees, Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction, respectively. Overnight, the mean breath VSC levels after using the four toothbrushes were lower than those observed at baseline. The respective mean levels of breath VSC were 266.5 ppb+/-269.9 ppb, 545.2 ppb+/-346.1 ppb, 567 ppb+/-335.7 ppb, and 554.6 ppb+/-398.4 ppb. Only the Colgate 360 degrees toothbrush provided a statistically significant reduction (P < .05) in breath VSC vs baseline. Additionally, the Colgate 360 degrees toothbrush was statistically significantly better (P < .05) than the three commercial toothbrushes in reducing breath VSC. Therefore, the results of this randomized, crossover clinical study indicate that a newly designed manual toothbrush with a tongue-cleaning implement on the back of the brush head was significantly more effective than three commercially available toothbrushes in reducing morning breath VSC associated with oral malodor.

Driving toothbrush innovation through a cross-functional development team

A cross-functional team was assembled to take on the project of developing a toothbrush that could deliver a "whole mouth clean." As such, this brush needed to not only demonstrate superior plaque removal from teeth, it also needed to provide a means for safe cleaning of soft oral tissues. During use, the brush needed to be comfortable both in hand and in mouth, and it required contemporary esthetics to help drive consumer acceptance. This article will take the reader through the full development cycle of the new toothbrush, identifying the proposed benefit of each brush feature along the way. Where appropriate, care was taken to identify the specific insights leading to the development of several new features not previously seen in commercial toothbrushes. This article also will attempt to demonstrate the value of forming new product development teams with representatives of multiple functional areas, including marketing, product development, advanced technology, clinical, engineering, and manufacturing.

Clinical comparison of Colgate Total Advanced Fresh vs a commercially available fluoride breath-freshening toothpaste in reducing breath odor overnight: a multiple-use study

The objective of this randomized, crossover study was to compare the effectiveness of Colgate Total Advanced Fresh toothpaste to a commercially available breath-freshening dentifrice containing fluoride for its ability to reduce volatile sulfur compounds (VSC) responsible for breath odor overnight. The study followed a two-treatment, two-period crossover design. Subjects were given a test product, along with a soft-bristled toothbrush, and instructed to brush their teeth for 1 minute, twice daily (once in the morning and the evening) using the assigned dentifrice for 7 consecutive days. After their evening brushing on the seventh day, subjects reported to the testing facility without oral hygiene, eating, or drinking for the overnight evaluation. After a washout period, subjects repeated the same regimen, now using the other test product. The levels of breath VSC were evaluated instrumentally using a gas chromatograph equipped with a flame photometric detector.

Clinical efficacy of Colgate Total Advanced Fresh and a commercially available breath-freshening dentifrice in reducing mouth-odor-causing bacteria

The objective of this double-blind clinical study was to compare the long-lasting overnight (10- to 12-hour) and 4-hour effects of Colgate Total Advanced Fresh toothpaste to a commercial fluoridated breath-freshening dentifrice in controlling the level of mouth-odor-causing bacteria. Thirty-two adult men and women from New Jersey participated in the randomized, crossover design clinical study. After a 1-week "washout" period of brushing with a regular fluoride dentifrice, subjects refrained from dental hygiene, eating, and drinking in preparation for the morning visit. After providing a baseline salivary sample, subjects were issued a soft-bristled toothbrush and instructed to brush their teeth twice a day (once in the morning and once before bed) for 1 minute with the assigned test dentifrice. After a 7-day product use cycle, the subjects returned to the test site, having refrained from dental hygiene, eating, and drinking. Subjects provided an overnight salivary sample (10 to 12 hours postbrushing). Subjects then ate, brushed for 1 minute with the assigned dentifrice, and returned for 2- and 4-hour postbrushing evaluations. Subjects refrained from dental hygiene, eating, or drinking during the 4-hour evaluation period. To collect the oral microflora samples, subjects rinsed with 10 mL of sterile water for 10 seconds and deposited their samples into sterile tubes. Each collected sample was serially diluted in sterile phosphate-buffered saline and duplicate-plated onto lead acetate agar. When plated onto this medium, mouth-odor-causing bacteria that produce hydrogen sulfide appear as dark pigmented colonies. After 96 hours of incubation, hydrogen-sulfide-producing bacteria were counted, expressed as log colony-forming units per milliliter, and reduction from baseline was calculated. The results of this clinical study support the conclusion that Colgate Total Advanced Fresh provides a significantly greater reduction in mouth-odor-causing bacteria than a commercial fluoridated breath-freshening dentifrice (P < or = 0.05).

In vitro efficacy of Colgate Total advanced fresh

Generally, clinical studies using organoleptic judges, gas chromatography, or a sulfide monitor have been employed in the assessment of treatments for the control of oral malodor. However, these studies can be expensive and time consuming. Also, for agents whose safety has not been proven, these methods are not appropriate. Therefore, in vitro assessment is a critical step toward developing a new technology or implementing changes to an existing formula. The in vitro methods employed in this study combined basic microbiology methods, such as growth inhibition and zone of inhibition experiments. In addition, a newly developed, in vitro, volatile sulfur compounds (VSC) experiment that combined the essential elements of zone of inhibition, head space analysis, and dynamic flow cell techniques was also employed. The in vitro VSC method has been validated using technologies clinically proven to control oral malodor. All in vitro experiments have demonstrated that Colgate Total Advanced Fresh toothpaste has efficacy similar to that of the original Colgate Total toothpaste and that both variants showed superior efficacy to the control toothpaste. These results have been corroborated by clinical study results.

The technology behind Colgate Total Advanced Fresh

In the early 1990s, a breakthrough toothpaste, Colgate Total, was launched with documented long-lasting activity against plaque, gingivitis, calculus, tooth decay, and bad breath. The technology behind this toothpaste is the combination of triclosan, a polyvinylmethylether/maleic acid copolymer, and sodium fluoride. The copolymer ensures maximal oral retention and subsequent release of the antibacterial triclosan. Effective levels of triclosan have been observed in the oral cavity 12 hours after brushing the teeth, allowing prolonged control of oral bacteria that may cause the most common dental problems, including bad breath. Similarly, the enhanced retention of triclosan to oral surfaces after using this revolutionary toothpaste for up to 2 years has led to significantly reduced incremental coronal caries compared to an American Dental Association-Approved anticavity fluoride toothpaste. Furthermore, significantly less calcium remained in dental plaque after brushing the teeth with the triclosan/copolymer toothpaste, resulting in the formation of less tartar. In keeping with the multiple oral health benefits provided by Colgate Total, consumers are now offered a new dentifrice, Colgate Total Advanced Fresh, which provides the numerous therapeutic and esthetic benefits that are the hallmark of Colgate Total. The new dentifrice, which contains an impactful breath-freshening flavor, has been documented to provide sustained control of bad breath over 12 hours.

Breath-odor evaluation by detection of volatile sulfur compounds--correlation with organoleptic odor ratings

Volatile sulfur compounds are known to be major contributors to oral malodor, and their detection by gas chromatography (GC) is a commonly used method for evaluating breath odor in clinical trials. A custom-designed breath-sampling GC system was developed for this purpose. A clinical study was performed to compare the performance of this instrumental method to organoleptic evaluation by trained odor judges. A statistically significant correlation was found between the measured levels of volatile sulfurs and the ratings of the odor judges. Both methods performed similarly in evaluating the breath-freshening effects of two test products. These results demonstrate the strength of the GC method for evaluating breath odor and predicting the breath-freshening effects of oral-care products.

The scientific rationale and development of an optimized stannous fluoride dentifrice, Part 1

Stannous fluoride has been recognized as an effective anticavity therapeutic agent since the early 1950s. There has recently been a resurgence in activity to discover ways to fully exploit its documented antimicrobial activity. Through the use of targeted in vitro methodology to predict in vivo efficacy, a highly optimized stannous fluoride dentifrice has been developed. Careful selection of stabilizing agents formulated into a unique system has resulted in a Colgate Optimized Stannous Fluoride (COSF) dentifrice that has been proven to simultaneously help control supragingival plaque, gingivitis, supragingival calculus, and caries. Furthermore, the COSF dentifrice has been clinically shown not to cause the traditional stannous fluoride staining of dentition.

Measurement of B --> K*gamma branching fractions and charge asymmetries

The branching fractions of the exclusive decays B0-->K(*0)gamma and B+-->K(*+)gamma are measured from a sample of (22.74+/-0.36)x10(6) BB decays collected with the BABAR detector at the PEP-II asymmetric e(+)e(-) collider. We find B (B0-->K(*0)gamma) = [4.23+/-0.40(stat)+/-0.22(syst)]x10(-5), B(B+-->K(*+)gamma) = [3.83+/-0.62(stat)+/-0.22(syst)]x10(-5) and constrain the CP-violating charge asymmetry to be -0.170<A(CP)(B-->K(*)gamma)<0.082 at 90% C.L.

Search for the decay B0-->gammagamma

We present a limit on the branching fraction for the decay B0-->gammagamma using data collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric energy e+e- collider. Based on the observation of one event in the signal region, out of a sample of 21.3x10(6) e+e--->Upsilon(4S)-->BB decays, we establish an upper limit on the branching fraction of B(B0-->gammagamma)<1.7x10(-6) at the 90% confidence level. This result substantially improves upon existing limits.

Measurement of the B--> J/psiK*(892) decay amplitudes

We present a measurement of the decay amplitudes in B-->J/psiK*(892) channels using 20.7 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at PEP-II. We measure a P-wave fraction R(perpendicular) = (16.0 +/- 3.2 +/- 1.4)% and a longitudinal polarization fraction (59.7 +/- 2.8 +/- 2.4)%. The measurement of a relative phase that is neither 0 nor pi, phi = 2.50 +/- 0.20 +/-0.08 radians, favors a departure from the factorization hypothesis. Although the decay B-->/psiK(pi) proceeds mainly via K*(892), there is also evidence for K2*(1430) and K(pi) S-wave contributions.

Measurements of the branching fractions of exclusive charmless B meson decays with eta(') or omega mesons

We present the results of searches for B decays to charmless two-body final states containing eta(') or omega mesons, based on 20.7 fb(-1) of data collected with the BABAR detector. We find the branching fractions Beta(B(+)-->eta(')K(+)) = (70+/-8+/-5) x 10(-6), Beta(B(0)-->eta(')K(0)) = (42(+13)(-11) +/- 4) x 10(-6), and Beta(B(+)-->omega pi(+)) = (6.6(+2.1)(-1.8) +/- 0.7) x 10(-6), where the first error quoted is statistical and the second is systematic. We give measurements of four additional modes for which the 90% confidence level upper limits are Beta(B(+)-->eta(')pi(+)) < 12 x 10(-6), Beta(B(+)-->omega K(+)) < 4 x 10(-6), Beta(B(0)-->omega K(0)) < 13 x 10(-6), and Beta(B(0)-->omega pi(0)) < 3 x 10(-6).

Measurement of the B(0) and B(+) meson lifetimes with fully reconstructed hadronic final states

The B(0) and B(+) meson lifetimes have been measured in e(+)e(-) annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the Upsilon(4S) resonance. Events are selected in which one B meson is fully reconstructed in a hadronic final state while the second B meson is reconstructed inclusively. A combined fit to the B(0) and the B(+) decay time difference distributions yields tau(B(0)) = 1.546+/-0.032(stat)+/-0.022(syst) ps, tau(B(+)) = 1.673+/-0.032(stat)+/-0.023(syst) ps, and tau(B(+))/tau(B(0)) = 1.082+/-0.026(stat)+/-0.012(syst).

Measurement of J/psi production in continuum e(+)e(-) annihilations near square root of s = 10.6 GeV

The production of J/psi mesons in continuum e(+)e(-) annihilations has been studied with the BABAR detector at energies near the Upsilon(4S) resonance. The mesons are distinguished from J/psi production in B decays through their center-of-mass momentum and energy. We measure the cross section e(+)e(-)-->J/psi X to be 2.52+/-0.21+/-0.21 pb. We set a 90% C.L. upper limit on the branching fraction for direct Upsilon(4S)-->J/psi X decays at 4.7 x 10(-4).

Measurement of the decays B--> phiK and B--> phiK*

We have observed the decays B--> phiK and phiK(*) in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are B(B+--> phiK+) = (7.7(+1.6)(-1.4)+/-0.8)x10(-6), B(B0--> phiK0) = (8.1(+3.1)(-2.5)+/-0.8)x10(-6), B(B+--> phiK(*+)) = (9.7(+4.2)(-3.4)+/-1.7)x10(-6), and B(B0--> phiK(*0)) = (8.7(+2.5)(-2.1)+/-1.1)x10(-6). We also report the upper limit B(B+--> phipi(+))<1.4x10(-6) ( 90% C.L.).

Measurement of branching fractions and search for CP-violating charge asymmetries in charmless two-body B decays into pions and kaons

We present measurements, based on a sample of approximately 23x10(6) BB pairs, of the branching fractions and a search for CP-violating charge asymmetries in charmless hadronic decays of B mesons into two-body final states of kaons and pions. We find the branching fractions B(B0-->pi(+)pi(-)) = (4.1+/-1.0+/-0.7)x10(-6), B(B0-->K+pi(-)) = (16.7+/-1.6+/-1.3)x10(-6), B(B+-->K+pi(0)) = (10.8(+2.1)(-1.9)+/-1.0)x10(-6), B(B+-->K0pi(+)) = (18.2(+3.3)(-3.0)+/-2.0)x10(-6), B(B0-->K0pi(0)) = (8.2(+3.1)(-2.7)+/-1.2)x10(-6). We also report 90% confidence level upper limits for B meson decays to the pi(+)pi(0), K+K-, and K0K+ final states. In addition, charge asymmetries have been found to be consistent with zero, where the statistical precision is in the range of +/-0.10 to +/-0.18, depending on the decay mode.

Observation of CP violation in the B(0) meson system

We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.

Measurement of CP-violating asymmetries in B0 decays to CP eigenstates

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).

Lipid transfers between reconstituted high density lipoprotein complexes and low density lipoproteins: effects of plasma protein factors

In this study we examined the transfer of lipids between reconstituted high density lipoprotein discs (r-HDL) and human low density lipoproteins (LDL) in the presence and absence of lecithin:cholesterol acyltransferase (LCAT) or of plasma phospholipid transfer protein (PLTP). We found that spontaneous transfer of phospholipids from r-HDL to LDL occurred by an apparent first order reaction with a half-time of 5.8 to 6.9 hr depending on the phospholipid. During the time of incubation of r-HDL with LDL (from 0 to 25 hr), the phospholipid content of r-HDL decreased more than 30%, the free cholesterol content increased 2.5-fold, and low levels of cholesteryl esters appeared in r-HDL. These compositional changes gave rise to small discoidal particles with a limiting diameter of 77 A and two molecules of apoA-I per particle. When LCAT was included in the reaction mixture, the r-HDL lost even more phospholipid, lost some free cholesterol, and gained cholesteryl esters relative to the apolipoprotein content, due to the enzymatic reaction. The products of the LCAT reaction had a diameter of 93 A and three, rather than two, apoA-I molecules per particle. Inclusion of PLTP into the reaction mixture accelerated the transfer of phospholipids (half-time of 1.7 hr) and the formation of the 77 A product. In addition to these compositional and morphological changes, which may be important in the interconversions of native HDL subspecies, the prolonged incubations revealed some slow reactions, such as the esterification of LDL cholesterol by LCAT, a background formation of cholesteryl esters in r-HDL, and an apparent hydrolysis of cholesteryl esters in LDL in the presence of r-HDL.

Dihydro-orotase from Clostridium oroticum. Purification and reversible removal of essential zinc

A new purification procedure involving five column-chromatography steps is described for dihydro-orotase (L-5,6-dihydro-orotate amidohydrolase, EC 3.5.2.3) from Clostridium oroticum (A.T.C.C. 25750). The native purified enzyme is a dimer of Mr 102 000 and contains 4.0 +/- 0.3 g-atoms of zinc/mol of dimer. These observations agree with those reported previously [Taylor, Taylor, Balch & Gilchrist (1976) J. Bacteriol. 127, 863-873]. It is conclusively demonstrated that dihydro-orotase is a zinc metalloenzyme. Zinc is reversibly removed by treatment with chelators in phosphate buffer at pH 6.5, as demonstrated by atomic absorption spectrophotometry and decrease of enzyme activity. The specific activity is linearly dependent on zinc content. Addition of ZnSO4 to the chelator-treated enzyme results in regain of the normal complement of zinc and enzyme activity. Kinetic properties of the reconstituted enzyme are indistinguishable from those of the native enzyme. The amino acid composition of the homogeneous enzyme suggests that the zinc atoms occupy different environments.