An acute case of Pimelea elongata toxicity in cattle in western New South Wales

In May 2019, 96 cattle died from Pimelea toxicity in a period of 19 days after potential exposure, with the first deaths occurring within 5 days. After examining the circumstances, we suspect that several factors contributed to the deaths. These included that recently purchased stock and transported had access to flooded land containing Pimelea elongata. This weed species contains simplexin and 18 other compounds. Roots, flowers and seeds are significantly more toxic than the stem, branches and leaves. We suspect that thirsty and hungry stock consumed seed and roots from flooded pastures and consumed lethal doses of simplexin. Blood tests were not good indicators of the conditions. Management strategies are suggested.

Single-cell and single-nucleus RNA-seq uncovers shared and distinct axes of variation in dorsal LGN neurons in mice, non-human primates, and humans

Abundant evidence supports the presence of at least three distinct types of thalamocortical (TC) neurons in the primate dorsal lateral geniculate nucleus (dLGN) of the thalamus, the brain region that conveys visual information from the retina to the primary visual cortex (V1). Different types of TC neurons in mice, humans, and macaques have distinct morphologies, distinct connectivity patterns, and convey different aspects of visual information to the cortex. To investigate the molecular underpinnings of these cell types, and how these relate to differences in dLGN between human, macaque, and mice, we profiled gene expression in single nuclei and cells using RNA-sequencing. These efforts identified four distinct types of TC neurons in the primate dLGN: magnocellular (M) neurons, parvocellular (P) neurons, and two types of koniocellular (K) neurons. Despite extensively documented morphological and physiological differences between M and P neurons, we identified few genes with significant differential expression between transcriptomic cell types corresponding to these two neuronal populations. Likewise, the dominant feature of TC neurons of the adult mouse dLGN is high transcriptomic similarity, with an axis of heterogeneity that aligns with core vs. shell portions of mouse dLGN. Together, these data show that transcriptomic differences between principal cell types in the mature mammalian dLGN are subtle relative to the observed differences in morphology and cortical projection targets. Finally, alignment of transcriptome profiles across species highlights expanded diversity of GABAergic neurons in primate versus mouse dLGN and homologous types of TC neurons in primates that are distinct from TC neurons in mouse.

Biomarker testing in oncology - Requirements for organizing external quality assessment programs to improve the performance of laboratory testing: revision of an expert opinion paper on behalf of IQNPath ABSL

In personalized medicine, predictive biomarker testing is the basis for an appropriate choice of therapy for patients with cancer. An important tool for laboratories to ensure accurate results is participation in external quality assurance (EQA) programs. Several providers offer predictive EQA programs for different cancer types, test methods, and sample types. In 2013, a guideline was published on the requirements for organizing high-quality EQA programs in molecular pathology. Now, after six years, steps were taken to further harmonize these EQA programs as an initiative by IQNPath ABSL, an umbrella organization founded by various EQA providers. This revision is based on current knowledge, adds recommendations for programs developed for predictive biomarkers by in situ methodologies (immunohistochemistry and in situ hybridization), and emphasized transparency and an evidence-based approach. In addition, this updated version also has the aim to give an overview of current practices from various EQA providers.

Health resource utilization of labor induction versus expectant management

BACKGROUND

Although induction of labor of low-risk nulliparous women at 39 weeks reduces the risk of cesarean delivery compared with expectant management, concern regarding more frequent use of labor induction remains, given that this intervention historically has been thought to incur greater resource utilization.

OBJECTIVE

The objective of the study was to determine whether planned elective labor induction at 39 weeks among low-risk nulliparous women, compared with expectant management, was associated with differences in health care resource utilization from the time of randomization through 8 weeks postpartum.

STUDY DESIGN

This is a planned secondary analysis of a multicenter randomized trial in which low-risk nulliparous women were assigned to induction of labor at 39 weeks or expectant management. We assessed resource utilization after randomization in 3 time periods: antepartum, delivery admission, and discharge through 8 weeks postpartum.

RESULTS

Of 6096 women with data available, those in the induction of labor group (n = 3059) were significantly less likely in the antepartum period after randomization to have at least 1 ambulatory visit for routine prenatal care (32.4% vs 68.4%), unanticipated care (0.5% vs 2.6%), or urgent care (16.2% vs 44.3%), or at least 1 antepartum hospitalization (0.8% vs 2.2%, P < .001 for all). They also had fewer tests (eg, sonograms, blood tests) and treatments (eg, antibiotics, intravenous hydration) prior to delivery. During the delivery admission, women in the induction of labor group spent a longer time in labor and delivery (median, 0.83 vs 0.57 days), but both women (P = .002) and their neonates (P < .001) had shorter postpartum stays. Women and neonates in both groups had similar frequencies of postpartum urgent care and hospital readmissions (P > .05 for all).

CONCLUSION

Women randomized to induction of labor had longer durations in labor and delivery but significantly fewer antepartum visits, tests, and treatments and shorter maternal and neonatal hospital durations after delivery. These results demonstrate that the health outcome advantages associated with induction of labor are gained without incurring uniformly greater health care resource use.

Conserved cell types with divergent features in human versus mouse cortex

Elucidating the cellular architecture of the human cerebral cortex is central to understanding our cognitive abilities and susceptibility to disease. Here we used single-nucleus RNA-sequencing analysis to perform a comprehensive study of cell types in the middle temporal gyrus of human cortex. We identified a highly diverse set of excitatory and inhibitory neuron types that are mostly sparse, with excitatory types being less layer-restricted than expected. Comparison to similar mouse cortex single-cell RNA-sequencing datasets revealed a surprisingly well-conserved cellular architecture that enables matching of homologous types and predictions of properties of human cell types. Despite this general conservation, we also found extensive differences between homologous human and mouse cell types, including marked alterations in proportions, laminar distributions, gene expression and morphology. These species-specific features emphasize the importance of directly studying human brain.

Classification of electrophysiological and morphological neuron types in the mouse visual cortex

Understanding the diversity of cell types in the brain has been an enduring challenge and requires detailed characterization of individual neurons in multiple dimensions. To systematically profile morpho-electric properties of mammalian neurons, we established a single-cell characterization pipeline using standardized patch-clamp recordings in brain slices and biocytin-based neuronal reconstructions. We built a publicly accessible online database, the Allen Cell Types Database, to display these datasets. Intrinsic physiological properties were measured from 1,938 neurons from the adult laboratory mouse visual cortex, morphological properties were measured from 461 reconstructed neurons, and 452 neurons had both measurements available. Quantitative features were used to classify neurons into distinct types using unsupervised methods. We established a taxonomy of morphologically and electrophysiologically defined cell types for this region of the cortex, with 17 electrophysiological types, 38 morphological types and 46 morpho-electric types. There was good correspondence with previously defined transcriptomic cell types and subclasses using the same transgenic mouse lines.

Psychological wellbeing and use of alcohol and recreational drugs: results of the British HIV Association (BHIVA) national audit 2017

OBJECTIVES

The aim of this national audit was to assess adherence of services providing HIV care in the UK to national standards and guidelines regarding psychological support and the assessment of alcohol and recreational drug use (including chemsex drugs) in people living with HIV (PLWH).

METHODS

Participating sites completed a survey of their services' care pathways relating to psychological support and substance use. They performed a case-note review of up to 40 adult PLWH per service, reviewing sociodemographic and clinical information and assessment of psychological wellbeing, drug use and alcohol use. The surveys and case notes were assessed against relevant British HIV Association (BHIVA) guidelines and standards.

RESULTS

The survey was completed by 112 services. Of these, 73%, 82% and 73% had formal annual processes for assessing the psychological wellbeing, alcohol use and drug use, respectively, of PLWH. Case-note data were provided for 4486 PLWH from 119 sites. Audited rates of assessment of PLWH were 66.0% for psychological wellbeing, 68.0% for alcohol use, 58.4% for recreational drug use and 16.8% for chemsex drug use. Variation between clinical services was wide, with ranges from < 10% to 100% routinely assessing PLWH for each of these domains. Services using assessment tools performed better.

CONCLUSIONS

Assessment of PLWH for psychological wellbeing and alcohol and recreational drug use is variable in UK clinics, with a significant minority of services not documenting that they assessed these factors routinely. Wider adoption of assessment tools or proformas to assess PLWH in these areas is likely to improve surveillance for psychological morbidity and problematic alcohol or drug use.

Single-nucleus and single-cell transcriptomes compared in matched cortical cell types

Transcriptomic profiling of complex tissues by single-nucleus RNA-sequencing (snRNA-seq) affords some advantages over single-cell RNA-sequencing (scRNA-seq). snRNA-seq provides less biased cellular coverage, does not appear to suffer cell isolation-based transcriptional artifacts, and can be applied to archived frozen specimens. We used well-matched snRNA-seq and scRNA-seq datasets from mouse visual cortex to compare cell type detection. Although more transcripts are detected in individual whole cells (~11,000 genes) than nuclei (~7,000 genes), we demonstrate that closely related neuronal cell types can be similarly discriminated with both methods if intronic sequences are included in snRNA-seq analysis. We estimate that the nuclear proportion of total cellular mRNA varies from 20% to over 50% for large and small pyramidal neurons, respectively. Together, these results illustrate the high information content of nuclear RNA for characterization of cellular diversity in brain tissues.

Shared and distinct transcriptomic cell types across neocortical areas

The neocortex contains a multitude of cell types that are segregated into layers and functionally distinct areas. To investigate the diversity of cell types across the mouse neocortex, here we analysed 23,822 cells from two areas at distant poles of the mouse neocortex: the primary visual cortex and the anterior lateral motor cortex. We define 133 transcriptomic cell types by deep, single-cell RNA sequencing. Nearly all types of GABA (γ-aminobutyric acid)-containing neurons are shared across both areas, whereas most types of glutamatergic neurons were found in one of the two areas. By combining single-cell RNA sequencing and retrograde labelling, we match transcriptomic types of glutamatergic neurons to their long-range projection specificity. Our study establishes a combined transcriptomic and projectional taxonomy of cortical cell types from functionally distinct areas of the adult mouse cortex.

Abstract P3-08-16: ER, PR and HER2 biomarkers in UK and Irish clinical breast cancer testing: analysis of results from &gt;168,000 patients

AIMS

To describe and analyse &gt;168,000 sets of results from clinical breast biomarker testing carried-out between 2009 and 2016 in the UK and Republic of Ireland, focussing on biological relationships. To present robust confirmatory evidence on known associations and provide new data on previously undescribed or unconfirmed ones.

BACKGROUND

Between Jan-2009 and Jan-2016 the UK National External Quality Assessment Scheme for Immunocytochemistry and In-situ Hybridisation (UK NEQAS ICC&ISH) collected results on clinical breast cancer testing, comprehensively for human epidermal growth factor receptor-2 (HER2) and optionally for estrogen receptor (ER) and progesterone receptor (PR), from most UK and Irish testing centres. Primary objectives were to assess and, where indicated achieve improvements in testing quality. The size and scope of the data-set is unparalleled in the literature and represent a significant reference resource for the breast cancer community.

METHODS

UK NEQAS ICC&ISH created and curated an on-line data-entry system allowing centres to systematically collect their own HER2, ER and PR results from clinical testing; for HER2, immunohistochemical (IHC) and in-situ hybridisation (ISH) data were collected; for ER and PR, IHC results could be entered according to local practise format. Tools and guidance were provided enabling centres to analyse their data for local audit and quality assurance. Clinicopathologic data was also collected, including: patient age at diagnosis, histological tumor type, tumor grade, site/stage (primary, recurrence, metastasis) and sample type (core, excision).

RESULTS

Data are present on 168,793 patients. 173 centres contributed ≥100 entries (96% of total). Median age was 62 years (IQR: 51-72). Tumor type was stated in 42%: 76% were invasive ductal, and 13% invasive lobular carcinoma. Grade was stated in 56%: 15% were Grade 1, 55% Grade 2 and 30% Grade 3. Site/stage was stated in 56%: 92% were primary, 2% recurrent and 6% metastatic. Sample type was stated in 70%: 75% were cores and 25%, excision.

Receptor statuses were available as follows; HER2 (100%): 87% negative, 13% positive; ER (45%): 15% negative, 85% positive; PR (31%): 29% negative, 71% positive.

HER2 data were available as follows; category by IHC: 91%; amplification status by ISH: 15%; HER2 gene/chromosome 17 (CEP17) ratio: 15% (86% of which were IHC 2+); HER2 gene copy number: 7%; CEP17 copy number: 7%.

HER2-positive rate was 24% in ER-negative and 11% in ER-positive cases. HER2-positive status was negatively associated with increasing ER positivity (rho -0.22, P&lt;0.001). 71% of HER2-positive cases were ER-positive and 29% were ER-negative. The HER2 2+ rate was 14% in ER-negative and 21% in ER-positive cases. Considering only IHC 2+ cases, median HER2 copy number was 5.4 in ER-negative and 4.4 in ER-positive disease.

Comprehensive description of significant associations for all parameters will be presented.

CONCLUSION

The unique size and scope of this data-set has allowed confirmation of known associations for HER2, ER and PR with clinicopathologic and biological characteristics in breast cancer to very high confidence levels, and has uncovered previously undescribed relationships in both ER-positive and ER-negative disease.

Citation Format: Dodson A, Parry S, Ibrahim M, Bartlett J, Dowsett M, Miller K. ER, PR and HER2 biomarkers in UK and Irish clinical breast cancer testing: analysis of results from &gt;168,000 patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-08-16.

On compression and damage evolution in two thermoplastics

The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.

Dynamic damage in carbon-fibre composites

The Taylor test is used to determine damage evolution in carbon-fibre composites across a range of strain rates. The hierarchy of damage across the scales is key in determining the suite of operating mechanisms and high-speed diagnostics are used to determine states during dynamic loading. Experiments record the test response as a function of the orientation of the cylinder cut from the engineered multi-ply composite with high-speed photography and post-mortem target examination. The ensuing damage occurs during the shock compression phase but three other tensile loading modes operate during the test and these are explored. Experiment has shown that ply orientations respond to two components of release; longitudinal and radial as well as the hoop stresses generated in inelastic flow at the impact surface. The test is a discriminant not only of damage thresholds but of local failure modes and their kinetics. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

A comprehensive transcriptional map of primate brain development

The transcriptional underpinnings of brain development remain poorly understood, particularly in humans and closely related non-human primates. We describe a high-resolution transcriptional atlas of rhesus monkey (Macaca mulatta) brain development that combines dense temporal sampling of prenatal and postnatal periods with fine anatomical division of cortical and subcortical regions associated with human neuropsychiatric disease. Gene expression changes more rapidly before birth, both in progenitor cells and maturing neurons. Cortical layers and areas acquire adult-like molecular profiles surprisingly late in postnatal development. Disparate cell populations exhibit distinct developmental timing of gene expression, but also unexpected synchrony of processes underlying neural circuit construction including cell projection and adhesion. Candidate risk genes for neurodevelopmental disorders including primary microcephaly, autism spectrum disorder, intellectual disability, and schizophrenia show disease-specific spatiotemporal enrichment within developing neocortex. Human developmental expression trajectories are more similar to monkey than rodent, although approximately 9% of genes show human-specific regulation with evidence for prolonged maturation or neoteny compared to monkey.

Adult mouse cortical cell taxonomy revealed by single cell transcriptomics

Nervous systems are composed of various cell types, but the extent of cell type diversity is poorly understood. Here, we construct a cellular taxonomy of one cortical region, primary visual cortex, in adult mice based on single cell RNA-sequencing. We identify 49 transcriptomic cell types including 23 GABAergic, 19 glutamatergic and seven non-neuronal types. We also analyze cell-type specific mRNA processing and characterize genetic access to these transcriptomic types by many transgenic Cre lines. Finally, we show that some of our transcriptomic cell types display specific and differential electrophysiological and axon projection properties, thereby confirming that the single cell transcriptomic signatures can be associated with specific cellular properties.

Systematic comparison of adeno-associated virus and biotinylated dextran amine reveals equivalent sensitivity between tracers and novel projection targets in the mouse brain

As an anterograde neuronal tracer, recombinant adeno-associated virus (AAV) has distinct advantages over the widely used biotinylated dextran amine (BDA). However, the sensitivity and selectivity of AAV remain uncharacterized for many brain regions and species. To validate this tracing method further, AAV (serotype 1) was systematically compared with BDA as an anterograde tracer by injecting both tracers into three cortical and 15 subcortical regions in C57BL/6J mice. Identical parameters were used for our sequential iontophoretic injections, producing injections of AAV that were more robust in size and in density of neurons infected compared with those of BDA. However, these differences did not preclude further comparison between the tracers, because the pairs of injections were suitably colocalized and contained some percentage of double-labeled neurons. A qualitative analysis of projection patterns showed that the two tracers behave very similarly when injection sites are well matched. Additionally, a quantitative analysis of relative projection intensity for cases targeting primary motor cortex (MOp), primary somatosensory cortex (SSp), and caudoputamen (CP) showed strong agreement in the ranked order of projection intensities between the two tracers. A detailed analysis of the projections of two brain regions (SSp and MOp) revealed many targets that have not previously been described in the mouse or rat. Minor retrograde labeling of neurons was observed in all cases examined, for both AAV and BDA. Our results show that AAV has actions equivalent to those of BDA as an anterograde tracer and is suitable for analysis of neural circuitry throughout the mouse brain.

Macrosomia has its roots in early placental development

INTRODUCTION

We sought to determine if early placental size, as measured by 3-dimensional ultrasonography, is associated with an increased risk of delivering a macrosomic or large-for-gestational age (LGA) infant.

METHODS

We prospectively collected 3-dimensional ultrasound volume sets of singleton pregnancies at 11-14 weeks and 18-24 weeks. Birth weights were collected from the medical records. After delivery, the ultrasound volume set were used to measure the placental volume (PV) and placental quotient (PQ = PV/gestational age), as well as the mean placental and chorionic diameters (MPD and MCD, respectively). Placental measures were analyzed as predictors of macrosomia (birth weight ≥4000 g) and LGA (birth weight ≥90th percentile).

RESULTS

The 578 pregnancies with first trimester volumes included 44 (7.6%) macrosomic and 43 (7.4%) LGA infants. 373 subjects also had second trimester volumes available. A higher PV and PQ were both significantly associated with macrosomia and LGA in both the first and second trimesters. Second trimester MPD was significantly associated with both outcomes as well, while second trimester MCD was only associated with LGA. The above associations remained significant after adjusting for maternal demographic variables such as race, ethnicity, age and diabetes. Adjusted models yielded moderate prediction of macrosomia and LGA (AUC: 0.71-0.77).

CONCLUSIONS

Sonographic measurement of the early placenta can identify pregnancies at greater risk of macrosomia and LGA. Macrosomia and LGA are already determined in part by early placental growth and development.

Two-dimensional sonographic placental measurements in the prediction of small-for-gestational-age infants

OBJECTIVES

To determine the utility of two-dimensional (2D) sonographic placental measurements in the prediction of small-for-gestational-age (SGA) infants.

METHODS

The maximal diameter along the fetal surface of the placenta and the maximal placental thickness were measured at 18-24 weeks' gestation, and the measurements repeated in the orthogonal plane. 'Biometric lags' were calculated as the difference between sonographic gestational age, estimated using each of a number of fetal biometric measurements, and actual gestational age. These variables were analyzed individually and in combination as predictors of birth weight<10(th) percentile (SGA<10) and <5(th) percentile (SGA<5).

RESULTS

1909 singleton pregnancies were included. Mean placental diameter (SGA<10, P<0.001; SGA<5, P=0.002) and thickness (SGA<10, P<0.006; SGA<5, P=0.065) were significantly smaller in SGA pregnancies. The biometric lags were greater in SGA pregnancies, the lag in abdominal circumference (AC) being the most predictive of SGA (P<0.0001). Multivariable models were significantly predictive of both SGA<10(th) percentile (area under the receiver-operating characteristics curve (AUC) =0.7404) and <5(th) percentile (AUC=0.7204), the best fitting models including AC lag and mean placental diameter and thickness.

CONCLUSIONS

2D placental measurements taken in mid-gestation are significantly associated with the incidence of SGA. Biometric lags can improve the predictive ability further. These easily obtained variables should be considered in future efforts to develop a clinically useful predictive model for adverse outcome of pregnancy.

Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes

BACKGROUND

Carriers of germline mutations in DNA mismatch repair (MMR) genes have a high risk of colorectal cancer (CRC), but the modifiers of this risk are not well established. We estimated an association between body mass index (BMI) in early adulthood and subsequent risk of CRC for carriers and, as a comparison, estimated the association for non-carriers.

METHODS

A weighted Cox regression was used to analyse height and weight at 20 years reported by 1324 carriers of MMR gene mutations (500 MLH1, 648 MSH2, 117 MSH6 and 59 PMS2) and 1219 non-carriers from the Colon Cancer Family Registry.

RESULTS

During 122,304 person-years of observation, we observed diagnoses of CRC for 659 carriers (50%) and 36 non-carriers (3%). For carriers, the risk of CRC increased by 30% for each 5 kg m(-2) increment in BMI in early adulthood (hazard ratio, HR: 1.30; 95% confidence interval, CI: 1.08-1.58; P=0.01), and increased by 64% for non-carriers (HR: 1.64; 95% CI: 1.02-2.64; P=0.04) after adjusting for sex, country, cigarette smoking and alcohol drinking (and the MMR gene that was mutated in carriers). The difference in HRs for carriers and non-carriers was not statistically significant (P=0.50). For MLH1 and PMS2 (MutLα heterodimer) mutation carriers combined, the corresponding increase was 36% (HR: 1.36; 95% CI: 1.05-1.76; P=0.02). For MSH2 and MSH6 (MutSα heterodimer) mutation carriers combined, the HR was 1.26 (95% CI: 0.96-1.65; P=0.09). There was no significant difference between the HRs for MutLα and MutSα heterodimer carriers (P=0.56).

CONCLUSION

Body mass index in early adulthood is positively associated with risk of CRC for MMR gene mutation carriers and non-carriers.

Periodontal infection and preterm birth: successful periodontal therapy reduces the risk of preterm birth

OBJECTIVE

This study tested the hypothesis that successful periodontal treatment was associated with a reduction in the incidence of spontaneous preterm birth (PTB).

DESIGN

This was a randomised, controlled, blinded clinical trial.

SETTING

Hospital outpatient clinic.

POPULATION

Pregnant women of 6-20 weeks of gestation were eligible.

METHODS

Of 322 pregnant women with periodontal disease, 160 were randomly assigned to receive scaling and root planing (SRP, cleaning above and below the gum line), plus oral hygiene instruction, whereas the remaining 162 received only oral hygiene instruction and served as an untreated control group. Subjects received periodontal examinations before and 20 weeks after SRP, and were classified blindly according to the results of treatment into two groups: successful ('non-exposure') and unsuccessful ('exposure') treatment. Groups were compared using standard inferential statistics; dichotomous variables were compared using the chi-square test or logistic regression. Results are presented in terms of odds ratios.

MAIN OUTCOME MEASURE

The main outcome measure was spontaneous preterm birth before 35 weeks of gestation.

RESULTS

No significant difference was found between the incidence of PTB in the control group (52.4%; n = 162) and the periodontal treatment group (45.6%; n = 160) (P < 0.13, Fisher's exact test). The incidence of PTB was compared within the periodontal treatment group, considering the success of therapy. A logistic regression analysis showed a strong and significant relationship between successful periodontal treatment and full-term birth (adjusted odds ratio 6.02; 95% CI 2.57-14.03). Subjects refractory to periodontal treatment were significantly more likely to have PTB.

CONCLUSIONS

A beneficial effect on PTB may be dependent on the success of periodontal treatment.