bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary structure of the two variants of a sperm‐specific histone H1 from the annelid Platynereis dumerilii
Authors: KMIECIK Daniel , SELLOS Daniel , BELAÏCHE Denise , SAUTIERE Pierre
Published: March 2005

The amino acid sequences of the two variants (H1a 121 residues and H1b 119 residues) of the sperm‐specific histone H1 from the polychaete annelid Platynereis dumerilii have been completely established.

Comparison of the sequences of these two variants shows one deletion of two residues in histone H1b and 22 substitents, of which most occur in the globular domain. The two variants differ highly in a sequence of nine residues adjacent to the conservative phenylalanine residue of histone H1 (64–72 in H1a, 62–70 in H1b) which makes H1a less hydrophobic than H1b.

The small molecular size of Platynereis H1a and H1b is a unique feature among the histones H1 of which the size ranges between 189 residues (chicken erythrocyte H5) and 248 residues (sea urchin sperm H1).

H1a and H1b have short N‐ and C‐terminal basic domains but the size of the globular domain (∼ 80 residues) is similar to that of other H1s.

In the globular region the variant H1a exhibits a close relationship with somatic or sperm H1s whereas the variant H1b is more related to H5 histones.
Regulation of the human‐erythrocyte hexose‐monophosphate shunt under conditions of oxidative stress
Authors: THORBURN David R. , KUCHEL Philip W.
Published: March 2005

The regulation of the hexose monophosphate shunt of human erythrocytes under conditions of oxidative stress has been investigated by monitoring the reduction of oxidised glutathione (GSSG) to reduced glutathione (GSH) in erythrocytes containing high levels of GSSG; 1H NMR and a biochemical assay were used to measure the changes.

A reconstituted metabolic system prepared with the purified erythrocyte enzymes was used in conjunction with studies of intact cells and haemolysates to determine the dependence of the rate of GSH production on the activities of hexokinase and glucose‐6‐phosphate dehydrogenase. Both of these enzymes have previously been claimed to be the rate‐limiting step of oxidatively stimulated flux through the hexose monophosphate shunt.

The absence of a kinetic isotope effect on the rate of GSH production in these systems, when [1‐2H]glucose replaced glucose as the source of reducing equivalents, showed that glucose‐6‐phosphate dehydrogenase activity was not a strong determinant of the flux. The dependence of the rate of GSH production on the concentration of the hexokinase inhibitors glucose 1,6‐bisphosphate and glycerate 2,3‐bisphosphate showed that, under conditions of oxidative stress, hexokinase was the principal determinant of flux through the shunt. Glucose 1,6‐bisphosphate at the concentration present in vivo appears to be more important in limiting hexokinase activity, and thus the rate of glucose utilisation, than was previously assumed.

A detailed computer model of the system was developed based on the reported kinetic parameters of the enzymes involved. A sensitivity analysis of this model predicted that the hexokinase reaction would have a sensitivity coefficient of 0.995 with respect to the maximal rate of GSH production.
Modifications of the expression of liver‐specific and non‐specific messenger RNAs during azo‐dye hepatocarcinogenesis
Authors: LAMAS Eugénia , SCHWEIGHOFFER Fabien , VAN ELS Cécile , BACHNER Lucien , MÅIE Joëlle , KAHN Axel
Published: March 2005

The expression of specific and non‐specific rat liver messenger RNAs has been studied during 3′ ‐methyl‐4‐(dimethylamino)azobenzene (3′‐MeDAB) carcinogenesis, using cDNA probes complementary to mRNAs encoding aldolase A and B, L‐type pyruvate kinase, albumin, α‐foetoprotein, transferrin and an unidentified 2.7 × 103‐base mRNA. mRNAs specific for undifferentiated cells, such as those encoding aldolase A and the unidentified 2.7 × 103‐base species were re‐expressed very early, being easily detectable at the 1st week of 3′‐MeDAB treatment. They reached a maximum of expression at the 4th week. Simultaneously the levels of aldolase B and L‐type pyruvate kinase mRNAs dramatically decreased as compared to controls, but remained responsive to induction by a high‐carbohydrate diet.

Albumin and transferrin mRNA levels were only slightly modified in the course of the carcinogenic diet. At the terminal stage of hepatocarcinogenesis, i.e. in malignant hepatoma cells, expression and inducibility of aldolase B and L‐type pyruvate kinase mRNAs were similar to those in normal adult rats while mRNAs specific for undifferentiated or foetal stages were also synthesized.

The very early changes in gene expression for aldolases A and B, L‐type pyruvate kinase and the 2.7 ×103 ‐base mRNA species could indicate that carcinogenic diet modifies gene control mechanisms long before inducing hepatoma.
Structures of shorthorn sculpin antifreeze polypeptides
Authors: HEW Choy L. , JOSHI Shashikant , WANG Nam‐Chiang , KAO Ming‐H , ANANTHANARAYANAN V. S.
Published: March 2005

The amino acid sequences of the two major antifreeze polypeptides (AFP) from the shorthorn sculpin have been determined using an automatic protein sequencer and enzymic digestion. These two polypeptides, SS‐3 and SS‐8, consist of 33 and 45 amino acid residues respectively. The N‐terminal methionyl residue is blocked in both the polypeptides. When aligned for maximum structural similarity these two AFP are 80% homologous, and there appears a deletion of 12 amino acid residues at the N‐terminal portion of SS‐3. Like the winter flounder AFP, both the sculpin AFP also contain the 11‐amino‐acid repeat sequences. The secondary structure of the sculpin AFP is mainly α‐helical as deduced from circular dichroic spectral data. The helical content of SS‐8 is high (73%), while that SS‐3 is moderate (about 45%). The latter exhibits a relatively weak antifreeze activity. Removal of the blocked N‐terminal residue in SS‐8 did not alter the helical content significantly but did reduce the antifreeze activity. Helical contents of proteolytically generated fragments of AFP are much lower, and they are devoid of activity. The α‐helix in the SS‐8 component is seen to be amphiphilic in character. The relevance of this feature to the mechanism of the antifreeze action is briefly discussed.
Imino proton NMR assignments and ion‐binding studies on Escherichia coli tRNA3Gly
Authors: HYDE Eva I.
Published: March 2005

The imino region of the proton NMR spectrum of Escherichia coli tRNA3Gly has been assigned mainly by sequential nuclear Overhauser effects between neighbouring base pairs and by comparison of assignments of other tRNAs. The effects of magnesium, spermine and temperature on the 1H and 31P NMR spectra of this tRNA were studied. Both ions affect resonances close to the G15 · C48 tertiary base pair and in the ribosylthymine loop. The magnesium studies indicate the presence of an altered tRNA conformer at low magnesium concentrations in equilibrium with the high magnesium form. The temperature studies show that the A7 · U66 imino proton (from a secondary base pair) melts before some of the tertiary hydrogen bonds and that the anticodon stem does not melt sequentially from the ends. Correlation of the ion effects in the 1H and 31P NMR spectra has led to the tentative assignment of two 31P resonances not assigned in the comparable 31P NMR spectrum of yeast tRNAPhe. 31P NMR spectra of E. coli tRNA3Gly lack resolved peaks corresponding to peaks C and F in the spectra of E. coli tRNAPhe and yeast tRNAPhe. In the latter tRNAs these peaks have been assigned to phosphate groups in the anticodon loop. Ion binding to E. coli tRNA3Gly and E. coli tRNAPhe has different effects on their 1H NMR spectra which may reflect further differences in their charge distribution and conformation.
The subcellular location in rat kidney of the peripheral benzodiazepine acceptor
Authors: O'BEIRNE Gerard B. , WILLIAMS D. Clive
Published: March 2005

In rat kidney high‐affinity binding sites for [3H]Ro‐5‐4864 and [3H]PK‐11195 with the properties of the peripheral‐type acceptor were found enriched in mitochondrial (M) and light‐mitochondrial‐lysosomal (L) fractions on differential centrifugation. When the combined M and L fractions were subjected to sucrose density gradient centrifugation, these binding sites were found enriched at a density of 1.155 g/ml coincident with a population of light mitochondria, whereas a population of heavier mitochondria (ϱ= 1.175 g/ml) had few or no binding sites. Transmission electron microscopy showed that whereas the heavier mitochondria appeared highly pure and intact, the lighter mitochondria appeared less intact and to be contaminated with vesicular structures. After fractionation of the light mitochondria and vesicles by centrifugation, both fractions showed the same ratio of [3H]Ro‐4864 binding sites to monoamine oxidase activity consistent with the vesicles being of mitochondrial outer‐membrane origin.

Digitonin pre‐treatment had no effect on the density of acceptor‐rich fractions on sucrose density gradient centrifugation. However, pretreatment with succinate/iodophenylnitrophenylphenyltetrazolium (INT) perturbed equally the density of acceptor‐rich fractions and mitochondrial marker enzymes.

When mitochondrial fractions were subjected to sonication prior to density gradient centrifugation the binding sites were now found highly enriched in a much lighter fraction coincident with the monoamine oxidase activity and thus consistent with being outer‐membrane vesicles.

When a mitochondrial fraction was subjected to hypotonic treatment before assay no evidence for activation/ unmasking of binding sites was found. The hypotonic treatment did not release any inhibitor of the binding sites.

These results are consistent with the peripheral benzodiazepine acceptor having an outer‐membrane location on a sub‐population of rat kidney mitochondria. Those mitochondria showing high levels of the acceptor are either light mitochondria or appear more susceptible to osmotic damage than those mitochondria in which the acceptor is absent or at low levels.
Molecular characterization of a Dictyostelium discoideum gene encoding a multifunctional enzyme of the pyrimidine pathway
Authors: FAURE Michel , CAMONIS Jacques H. , JACQUET Michel
Published: March 2005

We have isolated and characterized a Dictyostelium discoideum gene (PYRI‐3) encoding a multifunctional protein that carries the three first enzymatic activities of the de novo pyrimidine biosynthetic pathway. The PYRI‐3 gene is adjacent to another gene of the pyrimidine biosynthetic pathway (PYR4); the two genes are separated by a 1.5‐kb non‐coding sequence and transcribed divergently. The PYRI‐3 gene is transcribed to form a 7.5‐kb polyadenylated mRNA. As with the other genes of the pyrimidine biosynthetic pathway, the PYRI‐3 mRNA level is high during growth and decreases sharply during development. We have determined the nucleotide sequence of 63% of the coding region of the PYRI‐3 gene. We have identified the activities of the protein encoded by the D. discoideum PYRI‐3 gene by comparison of amino acid sequences with the products of genes of known function. The PYR1‐3 gene contains four distinct regions that probably correspond to four domains in the protein. From the NH2 extremity to the COOH extremity, these domains are: glutamine amidotransferase, carbamoylphosphate synthetase, dihydroorotase and aspartate transcarbamylase. This organization is identical to the one found in the rudimentary gene of Drosophila. The evolutionary implications of this finding are discussed.
Human epithelial tumor antigen cDNA sequences
Authors: WRESCHNER Daniel H. , HAREUVENI Mara , TSARFATY Ilan , SMORODINSKY Nechama , HOREV Judith , ZARETSKY Joseph , KOTKES Phillip , WEISS Mordechai , LATHE Richard , DION Arnold , KEYDAR Iafa
Published: March 2005

The isolation and characterization of complementary DNAs (cDNAs) which code for an epithelial antigen aberrantly expressed in human breast tumor tissue are described here. The only information regarding the primary structure of this potentially important antigen has been a 20‐amino‐acid repeat motif. We now report the complete amino acid sequences of different forms of the human epithelial tumor antigen as deduced from the nucleotide sequence of isolated non‐repeat cDNAs. The diversity of protein forms is generated by a series of alternative splicing events that occur in the regions located upstream and downstream to a central tandem repeat array. Isolated cDNAs coding for the upstream region show that differential usage of alternative splice acceptor sites may generate two protein forms containing putative signal peptides of varying hydrophobicities. The complexity of possible antigen forms is further compounded by alternative splicing events occurring in the region 3′ to the repeat array. The isolated cDNAs 3′ to the tandem repeats indicate that whereas one mRNA transcript is colinear with the gene, and defines an open reading frame (ORF) containing 160 amino acids downstream to the repeat array, a second cDNA correlates with a mRNA that is generated by a series of splicing events. The deduced amino acid sequence of the spliced cDNA contains an ORF that is identical for 149 amino acids downstream to the repeat array with the amino acid sequence of the unspliced cDNA. At this point it diverges and continues for an additional 179 amino acids. The sequence contains a highly hydrophobic 28‐amino‐acid peptide, located towards the carboxyl terminus, that may correspond to a transmembrane region. The cDNAs and deduced amino acid sequences, presented here, define the complete amino acid sequences of the epithelial tumor antigen and demonstrate the existence of multiple protein forms that probably localize to different cellular and extracellular compartments.
Fault rock analysis of the northern part of the Chelungpu Fault and its relation to earthquake faulting of the 1999 Chi‐Chi earthquake, Taiwan
Authors: Ujiie Kohtaro
Published: March 2005

Abstract  The 1999 Chi‐Chi earthquake in Taiwan (Mw = 7.6) produced a surface rupture along the north–south‐striking Chelungpu thrust fault with pure dip‐slip (east side up) and left lateral strike‐slip displacements. Near‐field strong‐motion data for the northern part of the fault illustrate a distinct lack of the high‐frequency seismic radiation associated with a large slip (10–15 m) and a rapid slip velocity (2–4 m/s), suggesting a smooth seismic slip associated with low dynamic frictional resistance on the fault. A drillhole was constructed at shallow depths in the possible fault zones of the northern part of the Chelungpu Fault, which may have slipped during the 1999 earthquake. One of the zones consists of a 20‐cm‐thick, unconsolidated fault breccia with a chaotic texture lacking both discrete slip surfaces (e.g. Riedel shears) and grain crushing. Other possible fault zones are marked by the narrow (less than a few centimeters) gouge zone in which clayey material intrudes into the damaged zone outside of the gouge zone. These characteristic fault rock textures suggest that the slip mechanisms at shallow levels during the earthquake involved either granular flow of initially unconsolidated material or slip localization under elevated pore pressure along the narrow clayey gouge zone. Because both mechanisms lead to low dynamic frictional resistance on the fault, the rapid seismic slip in the deep portions of the fault (i.e. the source region of strong‐motion radiation) could have been accommodated by frictionless slip on the shallow portions of the fault. The combination of strong‐motion data and fault rock analysis suggests that smooth slip associated with low dynamic friction occurred on both the deep and shallow portions of the fault, resulting in a large slip between the source region and the surface in the northern region.
Fractal size and spatial distributions of fault zones: An investigation into the seismic Chelungpu Fault, Taiwan
Authors: Otsuki Kenshiro , Uduki Takayuki , Monzawa Nobuaki , Tanaka Hidemi
Published: March 2005

Abstract  The fractality of fault zones of thickness T for the 248‐m‐long core from a borehole penetrating the northern segment of the seismic Chelungpu Fault, Taiwan, was analyzed. The frequency curve of T shows that the fractal dimension is normal when T is smaller than a characteristic thickness Tc, and it becomes abnormally large when T exceeds Tc. The fractal dimensions of size and spatial distributions of T increase as the mean distribution density of T increases, which is inconsistent with the evolution laws for ordinary brittle faults. This discrepancy implies that the thickening rate of T when T is more than Tc is not constant, but a decreasing function of fault displacement. The slow thickening rate is related to the elastohydrodynamic lubrication which was effective on the fault when T exceeds Tc. This slip instability mechanism can explain the large, fast and smooth slip on the northern segment of the Chelungpu Fault during the 1999 Chi‐Chi earthquake.
What Can PISA Tell Us About Teacher Shortages?
Authors: WHITE PATRICK , SMITH EMMA
Published: March 2005

The OECD's recent research initiative, Attracting, Developing and Retaining Effective Teachers (OECD 2002), has highlighted teacher supply and demand as an area of international concern. Using data collected in this area as part of a wider OECD initiative (the PISA 2000 study) an individual‐level analysis was conducted on the views on teacher recruitment and retention of 5416 headteachers, principals and administrators working in secondary schools in 25 countries. The findings showed considerable variation between countries in terms of perceptions of the impact of teacher shortages, inadequacy and turnover. Surprisingly, however, differences in the reports of headteachers working in the same countries were only rarely related to the size, location, or other characteristics of the schools in which they worked.

Although there has been considerable previous research into headteachers’ views on this issue, much of this research has been, by necessity, small scale and restricted to a single nation. This article provides a much larger scale perspective and allows international comparisons to be made.
Multiple-Bias Modelling for Analysis of Observational Data
Authors: Greenland Sander
Published: March 2005

Conventional analytic results do not reflect any source of uncertainty other than random error, and as a result readers must rely on informal judgments regarding the effect of possible biases. When standard errors are small these judgments often fail to capture sources of uncertainty and their interactions adequately. Multiple-bias models provide alternatives that allow one systematically to integrate major sources of uncertainty, and thus to provide better input to research planning and policy analysis. Typically, the bias parameters in the model are not identified by the analysis data and so the results depend completely on priors for those parameters. A Bayesian analysis is then natural, but several alternatives based on sensitivity analysis have appeared in the risk assessment and epidemiologic literature. Under some circumstances these methods approximate a Bayesian analysis and can be modified to do so even better. These points are illustrated with a pooled analysis of case–control studies of residential magnetic field exposure and childhood leukaemia, which highlights the diminishing value of conventional studies conducted after the early 1990s. It is argued that multiple-bias modelling should become part of the core training of anyone who will be entrusted with the analysis of observational data, and should become standard procedure when random error is not the only important source of uncertainty (as in meta-analysis and pooled analysis).
Uncertainty and Sensitivity Analysis Techniques as Tools for the Quality Assessment of Composite Indicators
Authors: Saisana M. , Saltelli A. , Tarantola S.
Published: March 2005

Composite indicators are increasingly used for bench-marking countries’ performances. Yet doubts are often raised about the robustness of the resulting countries’ rankings and about the significance of the associated policy message. We propose the use of uncertainty analysis and sensitivity analysis to gain useful insights during the process of building composite indicators, including a contribution to the indicators’ definition of quality and an assessment of the reliability of countries’ rankings. We discuss to what extent the use of uncertainty and sensitivity analysis may increase transparency or make policy inference more defensible by applying the methodology to a known composite indicator: the United Nations's technology achievement index.
On the Viral Safety of Plasma Pools and Plasma Derivatives
Authors: Vansteelandt S. , Goetghebeur E. , Thomas I. , Mathys E. , Van Loock F.
Published: March 2005

In the industrialized world, a range of medicinal products are manufactured on a large scale from pools made of thousands of human blood and plasma donations. Policy makers as well as the general public are aware of the hazards of contamination following accumulated risks of individual donations. Today, the manufacturing process must therefore consider a complex sequence of risk reducing interventions, including screening tests and quarantine periods on pools and individual donations. We estimate the residual risk of hepatitis C infection following such sequences of events. This is the most common blood-borne infection in the western world, which affects an estimated 170 million people worldwide. We investigate the benefits and drawbacks of each intervention and study at several stages the dependence of the screening process on operational parameters that can be optimized, such as the number of donations from different donors in the pool and the length of the quarantine period. This leads to alternative risk reducing strategies that may be more (cost) effective or optimal under specific criteria.
Unemployed Couples: The Labour Market Effects of Making Both Partners Search for Work
Authors: Dorsett Richard
Published: March 2005

The paper evaluates the effect of a recent change to unemployment benefit in the UK which requires both partners in a couple (rather than just one) to search for work. The difference-in-differences estimator is extended in two ways. First, variations in when the change was implemented are exploited to test and adjust for bias resulting from differential trends among the control group. Second, the approach is combined with matching to relax functional form restrictions. After several months, positive effects on exiting from benefits were detected but effects on entry to jobs were less apparent.
Measuring the Efficiency of Public Services: The Limits of Analysis
Authors: Smith Peter C. , Street Andrew
Published: March 2005

Policy makers are increasingly seeking to develop overall measures of the effi-ciency of public service organizations. For that, the use of ‘off-the-shelf’ statistical tools such as data envelopment analysis and stochastic frontier analysis have been advocated as tools to measure organizational efficiency. The analytical sophistication of such methods has reached an advanced stage of development. We discuss the context within which such models are deployed, their underlying assumptions and their usefulness for a regulator of public services. Four specific model building issues are discussed: the weights that are attached to public service outputs; the specification of the statistical model; the treatment of environmental influences on performance; the treatment of dynamic effects. The paper concludes with recommendations for policy makers and researchers on the development and use of efficiency measurement techniques.
The ADA guidelines on oral malodor products
Authors: Wozniak WT
Published: March 2005

For over 130 years the ADA has been an important information source on the safety and effectiveness of dental products. The Council has recently completed the development of Acceptance Program Guidelines for products used in the management of oral malodor. The ADA Seal Program will ensure that professional and consumer dental products meet rigorous ADA criteria for safety and effectiveness
In vitro models for oral malodor
Authors: Greenman J , Spencer P , McKenzie C , Saad S , Duffield J
Published: March 2005

A model is a representation of some real phenomena and contains aspects or elements of the real system to be modeled. The model reflects (or duplicates) the type of behavior (or mechanisms) seen in the real system. The main characteristic of any model is the mapping of elements or parameters found in the system being studied (e.g. tongue dorsum biofilm in situ) on to the model being devised (e.g. laboratory perfusion biofilm). Such parameters include correct physico‐chemical (abiotic) conditions as well as biotic conditions that occur in both model and reality. The main purpose of a model is to provide information that better explains the processes observed or thought to occur in the real system. Such models can be abstract (mental, conceptual, theoretical, mathematical or computational) or ‘physical’, e.g. in the form of a real disaggregated in vitro system or laboratory model. A wide range of different model systems have been used in oral biofilm research. These will be briefly reviewed with special emphasis on those models that have contributed most to knowledge in breath odor research. The different model systems used in breath odor research are compared. Finally, the requirements for developing an overall ‘bad breath model’ from considering the processes as a whole (real oral cavity, substrates in saliva, biotransformation by tongue microflora, odor gases in the breath) and extending this to the detection of malodor by the human nose will be outlined and discussed.
Clinical assessment of oral malodor intensity expressed as absolute value using an electronic nose
Authors: Nonaka A , Tanaka M , Anguri H , Nagata H , Kita J , Shizukuishi S
Published: March 2005

Objectives:  In our previous study, scores determined via a multiple linear regression method (EN‐MLR) involving an electronic nose provided objective halitosis‐related measurements; however, this model afforded only relative expression exclusively. The objective of this investigation was to assess clinically oral malodor intensity expressed as an absolute value using an electronic nose.

Subjects and methods:  Sixty‐six subjects were evaluated based on results of an actual organoleptic test (OLT), measurements of volatile sulfur compound (VSC) concentrations, a score representing malodor intensity (EN‐MI) as the absolute value and EN‐MLR measured with an electronic nose system. Oral health parameters were also examined.

Results:  The OLT score served as a benchmark. The area under the receiver‐operating characteristic (ROC) plots of EN‐MI score (0.975) was significantly larger than that of log VSC (0.896) (P = 0.036); however, the area did not differ significantly from that of EN‐MLR score (0.932). Percentage of teeth with pocket depth ≥4 mm, tongue coating score and plaque control record displayed meaningful association with EN‐MI score in multiple logistic regression analyses.

Conclusion:  Oral malodor intensity expressed as an absolute value employing an electronic nose may be a suitable method for clinical evaluation of oral malodor.
Use of n‐butanol as an odorant to standardize the organoleptic scale of breath odour judges
Authors: Saad S , Greenman J , Duffield J , Sudlow K
Published: March 2005

Objective:  The alcohol n‐butanol has been recommended for use as a standard odorant by various groups for the training or standardization of breath odour judges and sensory evaluation panels. The objective of this study is to assess the use of n‐butanol as a suitable odorant for organoleptic training of breath judges.

Methods:  One judge with full smell acuity was trained in the method of organoleptic assessment using odorant solutions of main chemical classes (acids, amines, indole and sulphides) with the exception of alcohols. The subject was proficient in scoring odorant solutions, standard gas mixtures and human breath using the Rosenberg 0–5 organoleptic scale. A wide range of n‐butanol solutions were prepared from 0 to 90 000 ppm and dispensed as replicate 12‐ml volumes in Universal bottles (24 ml) leaving a headspace of 12 ml. Sets of odorants were prepared, labelled by code, randomized and presented to the judge in a completely blind fashion. The judge scored each concentration. This process was repeated on 32 occasions over a period of 12 weeks. Mean values of data for each determination for each concentration series were plotted against the log concentrations of odorant. Linear regression slope analysis was used to measure slope, the 95% CI of slope and the scatter of points (R2 value). Headspace concentrations of odorant were determined using gas chromatography (GC) analysis.

Results:  The n‐butanol regression slope gave a high R2 value (0.971) and low scatter. However, the data did not correspond to other published work using an ASTM method where the range of recommended butanol concentrations was insufficient at both the high and low ends to determine the top and threshold. Moreover, headspace analysis using GC confirmed the published gas concentrations to be in error by a factor of 100. It was also observed that high concentrations of odorants were irritant causing desensitization if used for prolonged periods.

Conclusion:  The published method had erroneous headspace calculations listed and n‐butanol could not be recommended as a training odorant because of its irritancy.
Breath odor evaluation by detection of volatile sulfur compounds – correlation with organoleptic odor ratings
Authors: Hunter CM , Niles HP , Vazquez J , Kloos C , Subramanyam R , Williams MI , Cummins D , Lenton PA , Majerus GJ
Published: March 2005

Background:  Detection of oral volatile sulfur compounds (VSC) by gas chromatography (GC) is a widely used method for evaluating breath odor. Air aspirated from the mouth is injected into the GC column for analysis. To eliminate discrepancies caused by variations in operator sampling or injection techniques, a new GC system designed to aspirate breath samples directly into the GC was developed.

Objective:  A clinical study was performed to compare this new automated breath‐sampling GC system to organoleptic evaluation by two trained odor judges.

Methods:  A randomized, two‐cell, double‐blind, parallel design was used in which subjects were tested before and 3 h after using either a mouthrinse containing zinc or a matching placebo rinse. Thirteen subjects used the zinc mouthrinse, and 12 used the placebo. Subjects with a wide range of VSC levels were studied. The average organoleptic ratings for each subject at each time‐point were compared with the average VSC measurements made with the GC, and Pearson product–moment correlation coefficients between the corresponding GC and organoleptic measurements were determined.

Results:  The correlation between the GC and organoleptic assessment methods were highly significant (P ≤ 0.001) for: total VSC, 0.65; H2S, 0.63; CH3SH, 0.61; and (CH3)2S, 0.46. The correlation between the two judges was also highly significant (0.823, P < 0.001).

Conclusion:  These results demonstrate the utility of the automated GC method for evaluating breath odor.
The clinical comparison of a triclosan/copolymer/fluoride dentifrice vs a breath‐freshening dentifrice in reducing breath odor overnight: a crossover study
Authors: Niles HP , Hunter C , Vazquez J , Williams MI , Cummins D
Published: March 2005

Objective:  The objective of this randomized, crossover study was to compare the effectiveness of the triclosan/copolymer/sodium fluoride (TCF‐AF) dentifrice and a commercially available breath‐freshening dentifrice containing fluoride for their ability to reduce volatile sulfur compounds (VSC) associated with oral malodor overnight.

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 breath sampling. 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 day 8, subjects returned to the test site, having refrained from oral hygiene, eating and drinking, for overnight sampling. Following a second 1‐week washout period, subjects repeated the same regimen, but now using the other test product. At each measurement, the level of breath VSC was evaluated 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.

Results:  At baseline, the mean breath VSC levels for the TCF‐AF and breath‐freshening dentifrice were 618 and 581 ppb respectively. There was no statistically significant difference between the baseline levels. Overnight, the TCF‐AF and the breath‐freshening dentifrice reduced breath mean VSC levels to 267 and 521 ppb respectively. This gave a 56.7 and 10.2% reduction in VSC levels for these two products, respectively, compared with baseline. The reduction for the TCF‐AF dentifrice was significantly different (P < 0.05%) from that of the breath‐freshening dentifrice.

Conclusion:  The results of this randomized, double‐blind, crossover study indicate that the TCF‐AF dentifrice was significantly more effective than a commercially available breath‐freshening dentifrice containing fluoride in reducing breath VSC associated with bad breath overnight.
Microbiological culture analysis of the tongue anaerobic microflora in subjects with and without halitosis
Authors: Donaldson AC , McKenzie D , Riggio MP , Hodge PJ , Rolph H , Flanagan A , Bagg J
Published: March 2005

Objective:  Determination of the microflora present on the tongue dorsum of subjects with and without halitosis using conventional microbiological culture methods.

Methods:  Twenty‐one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10‐fold dilutions to 10−7 were carried out. Samples were plated onto fastidious anaerobe agar (FAA) and FAA enriched with vancomycin. These were incubated under anaerobic conditions for 10 days at 37°C. Strict anaerobes were identified by metronidazole sensitivity and bacteria were identified to genus level by a combination of colony morphology, Gram staining and biochemical and enzymatic tests (rapid ID 32 A).

Results:  The predominant species in test and control groups were Veillonella sp. and Prevotella sp. Greater species diversity was found in the halitosis samples compared with controls. The halitosis samples contained an increased incidence of unidentifiable Gram‐negative rods, Gram‐positive rods and Gram‐negative coccobacilli.

Conclusions:  There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process.
Clinical efficacy of a triclosan/copolymer/NaF dentifrice and a commercially available breath‐freshening dentifrice on hydrogen sulfide‐forming bacteria
Authors: Vazquez J , Pilch S , Williams MI , Cummins D
Published: March 2005

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 H2S‐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.
Association between oral malodour and periodontal disease‐related parameters in a population of 71 Israelis
Authors: Stamou E , Kozlovsky A , Rosenberg M
Published: March 2005

The aim of the present study was to determine whether oral malodour and periodontal disease parameters are associated with one another in 71 Israeli subjects (mean age 36.2 ± 18.4; ages ranging from 15 to 65). Parameters measured included whole mouth odour judge scoring, Halimeter, OK to Kiss test, gingival index, plaque index and probing depth. Odour judge scores were significantly associated with Halimeter® (r = 0.55; P < 0.001), as well as the OK to Kiss test (r = 0.52; P < 0.001). However, neither gingival index, plaque index nor probing depth was significantly associated with odour judge scores or Halimeter® scores. Logistic regression analysis showed that both Halimeter® and OK to Kiss scores factored significantly (P = 0.005 and 0.018, respectively, odds ratios 14.9 and 2.7, respectively) in predicting the severity of oral malodour. Results suggest that in the population studied, periodontal health and oral malodour are not associated with one another.
The analysis of characteristics of elderly people with high VSC level
Authors: Aizawa F , Kishi M , Moriya T , Takahashi M , Inaba D , Yonemitsu M
Published: March 2005

Objective:  The purpose of this study was to examine the characteristics of elderly subjects who had objectionable levels of volatile sulfur compound (VSC).

Subjects and method:  In 2002, a total of 115 85‐year‐old persons in Japan were subjected to oral examinations, tongue coat collections, measurements of VSCs levels inside the mouth using a portable gas chromatography (Oral ChromaTM, Abilit, Japan), and assessments of quality of life (QOL) using an SF‐36 questionnaire.

Results:  Sixty‐six of the subjects were edentulous and 49 were dentulous. They were divided into two groups by VSC levels, those with oral malodor (both H2S > 112 ppb and CH3SH > 26 ppb; subjects with oral malodor, OM group; n = 7) and those without (n = 108). Our results showed that tongue coat deposit amounts and proportion of dentulous subjects were significantly higher in the OM group. Further, in an analysis of QOL, the SF‐36 scores for vitality, social functioning and mental health were significantly higher in OM.

Conclusion:  We found that elderly subjects with oral malodor tended to be dentulous and had large deposits of tongue coating. However, oral malodor in the OM group subjects did not appear to cause a disadvantage in their social lives.
Halitosis and periodontal disease in subjects with mental disabilities
Authors: de Figueiredo LC , Feres M , Salvador SL
Published: March 2005

Objective:  The aim of this study was to investigate the relationship between halitosis, presence of N‐benzoyl‐DL‐arginine‐2‐naphthylamide (BANA) positive activity (indicative of Treponema denticola, Porphyromonas gingivalis, Tannerella forsythensis) and periodontal conditions in subjects with mental disabilities.

Materials and methods:  The population consisted of 17 Down syndrome (DS), 17 mentally retarded (MR) and 17 mentally healthy subjects (MH) – control group. A portable sulfide monitor was used to measure the concentration of volatile sulfur compounds (VSC) found in the mouth. Clinical parameters [Plaque Index (PlI), Probing Depth (PD), Bleeding on Probing (BOP)] were obtained from six reference teeth. Subgingival plaque samples for BANA Test were taken from the same six teeth and dorsum of the tongue.

Results:  PlI and BOP were higher in DS than in MR and MH, respectively (P < 0.05). Mean PD was similar between DS and healthy groups but it was higher than the MR group. No significant differences were found among the three groups regarding the presence of BANA positive species, however the VSC levels were significantly lower in DS (97.23 ppb) than in MR (203.23 ppb) and MH individuals (180.53 ppb).

Conclusions:  Even though the presence of BANA positive activity was similar among DS, MR and MH subjects, halitosis seemed to be lower in the DS group.
Subjective patients’ opinion and evaluation of halitosis using halimeter and organoleptic scores
Authors: Iwanicka‐Grzegorek E , Michalik J , Kepa J , Wierzbicka M , Aleksinski M , Pierzynowska E
Published: March 2005

Objectives:  The aim of the study was to evaluate the level of interest in fetor ex ore among respondents, patients of the Department of Conservative Dentistry in Warsaw.

Materials and Methods:  A questionnaire was completed by 295 patients, 202 females and 93 males aged 18–74 years (average 38.73 years). Each person was also examined for organoleptic score and volatile sulfur compounds (VSC) by Halimeter. Halitosis was diagnosed if the average level of VSC was ≥125 ppb and the organoleptic measurement using a 0–5 point scale was ≥2. Statistical analysis was performed using chi‐square test.

Results:  Incidence of halitosis was greatest in age ranges 25–34 years (29.68%) and 45–54 years (24.52%). Sixty‐eight (43.87%) persons with diagnosed halitosis frequently reported having a problem with bad breath and only 5.81% persons with halitosis did not notice this problem (P < 0.001). Among 54 healthy persons three (5.56%) reported having a problem with halitosis (P < 0.001).

Conclusion:  A statistically significant correlation was found between clinical organoleptic diagnosis of halitosis and VSC level by halimeter. Subjective patients’ opinion correlated well with objective evaluation of halitosis.
O10  The technology behind Colgate® TotalTM toothpaste
Authors: Williams M , Ummins DC
Published: March 2005

In the early 1990s, a break‐through toothpaste, known as 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 polyvinyl methyl ether maleic acid (PVM/MA) copolymer and sodium fluoride (TCF). The function of the copolymer is to ensure optimal oral retention and prolonged release of the antibacterial triclosan. Effective levels of triclosan have been measured in the oral cavity 12 h after brushing the teeth. This allows prolonged control of oral bacteria that can lead to the formation of dental plaque and gingivitis and bad breath. Similarly, the retention of triclosan to oral surfaces during 2 years regular use of the product has led to a significant reduction in incremental coronal caries compared to an ADA‐approved anti‐cavity fluoride toothpaste. Furthermore, significantly less calcium phosphate has been shown to be present in dental plaque after brushing the teeth with the triclosan/copolymer toothpaste, and this has resulted in the reduced formation of tartar. A new variant of the triclosan/copolymer/fluoride toothpaste, having the numerous therapeutic and aesthetic benefits of the original formula, has been made available to consumers. The new dentifrice, which contains an impactful breath freshening flavor, has been documented to be significantly better (P < 0.05) than a control toothpaste in providing sustained control of bad breath over 12 h. After 12 h, breath odor was reduced from 51% compared to the control. The long term retention and subsequent release of triclosan by the copolymer in the TCF formula provide consumers protection against plaque, gingivitis, tartar, caries and bad breath.
O11  Effect of oral health care on the recovery from surgery in elderly patients by measuring volatile sulphur compounds
Authors: Yoshihara A , Sato M , Miyazaki H
Published: March 2005

Oral health care is suggested to be an effective method to decrease pathogenic microorganisms. The purpose of this study was to investigate the effect of oral health care on the recovery from gastrointestinal operations in elderly patients. For this objective, randomized control trials were used for 30 patients (70–80 years old) with gastrointestinal diseases. Infection control was done by antibiotics instillation before and after operations in general and by povidone–iodine solution in the oral cavity both in the intervention (test) group and the control group. For the intervention group, in addition, manual tooth brushing and tongue cleaning were advocated to reduce bacterial putrefaction. A simple gas chromatograph (Oral Chroma®, Abilit Co., Japan) was used to measure hydrogen sulphide, methyl mercaptan and dimethyl sulphide concentrations in the mouth air. Furthermore, oral microorganisms were isolated in tonsils. For 5 days after surgery, the increments of mean values of hydrogen sulphide, methyl mercaptan and dimethyl sulphide in the test group were 0.81 ± 4.86 ng/10 ml, 0.40 ± 1.72 ng/10 ml and 0.16 ± 1.60 ng/10 ml, respectively. On the other hand, those in control group were 2.93 ± 8.09 ng/10 ml, 1.10 ± 2.30 ng/10 ml and 0.36 ± 1.13 ng/10 ml, respectively. The differences in methyl mercaptan concentration between the test and the control groups were statistically significant (P < 0.001). In addition, the mean number of kinds of microorganisms in each patient's tonsils in the test and the control groups were 3.08 ± 0.95 and 3.64 ± 1.34 before surgery and were 2.62 ± 0.65 and 3.50 ± 1.74 5 days after, respectively (P < 0.05). The oral cavity is a potential reservoir of pathogenic microorganisms. These results demonstrated that oral health care to remove pathogens from dental biofilm or tongue coating can decrease levels of oral malodor and may also reduce the risk of systemic diseases.