Identification of Patients With Variants in TPMT and Dose Reduction Reduces Hematologic Events During Thiopurine Treatment of Inflammatory Bowel Disease

BACKGROUND & AIMS

More than 20% of patients with inflammatory bowel disease (IBD) discontinue thiopurine therapy because of severe adverse drug reactions (ADRs); leukopenia is one of the most serious ADRs. Variants in the gene encoding thiopurine S-methyltransferase (TPMT) alter its enzymatic activity, resulting in higher levels of thiopurine metabolites, which can cause leukopenia. We performed a prospective study to determine whether genotype analysis of TPMT before thiopurine treatment, and dose selection based on the results, affects the outcomes of patients with IBD.

METHODS

In a study performed at 30 Dutch hospitals, patients were assigned randomly to groups that received standard treatment (control) or pretreatment screening (intervention) for 3 common variants of TPMT (TPMT*2, TPMT*3A, and TPMT*3C). Patients in the intervention group found to be heterozygous carriers of a variant received 50% of the standard dose of thiopurine (azathioprine or 6-mercaptopurine), and patients homozygous for a variant received 0%-10% of the standard dose. We compared, in an intention-to-treat analysis, outcomes of the intervention (n = 405) and control groups (n = 378) after 20 weeks of treatment. Primary outcomes were the occurrence of hematologic ADRs (leukocyte count < 3.0*10(9)/L or reduced platelet count < 100*10(9)/L) and disease activity (based on the Harvey-Bradshaw Index for Crohn's disease [n = 356] or the partial Mayo score for ulcerative colitis [n = 253]).

RESULTS

Similar proportions of patients in the intervention and control groups developed a hematologic ADR (7.4% vs 7.9%; relative risk, 0.93; 95% confidence interval, 0.57-1.52) in the 20 weeks of follow-up evaluation; the groups also had similar mean levels of disease activity (P = .18 for Crohn's disease and P = .14 for ulcerative colitis). However, a significantly smaller proportion of carriers of the TPMT variants in the intervention group (2.6%) developed hematologic ADRs compared with patients in the control group (22.9%) (relative risk, 0.11; 95% confidence interval, 0.01-0.85).

CONCLUSIONS

Screening for variants in TPMT did not reduce the proportions of patients with hematologic ADRs during thiopurine treatment for IBD. However, there was a 10-fold reduction in hematologic ADRs among variant carriers who were identified and received a dose reduction, compared with variant carriers who did not, without differences in treatment efficacy. ClinicalTrials.gov number: NCT00521950.

The oxidative metabolism of metoprolol in human liver microsomes: inhibition by the selective serotonin reuptake inhibitors

OBJECTIVE

Biotransformation of metoprolol to alpha-hydroxymetoprolol (HM) and O-demethylmetoprolol (ODM) is mediated by CYP2D6. The selective serotonin reuptake inhibitors (SSRIs) are known to inhibit CYP2D6. The aim was to study in vitro the potential inhibitory effect of SSRIs on metoprolol biotransformation.

METHODS

Using microsomes from two human livers, biotransformation of metoprolol to alpha-hydroxymetoprolol (HM) and O-demethylmetoprolol (ODM) as a function of the concentrations of the SSRIs and of some of their metabolites was studied.

RESULTS

The kinetics of the formation of both metabolites are best described by a biphasic enzyme model. The estimated values of Vmax and kM for the high affinity site are for the alpha-hydroxylation in human liver HL-1 32 pmol mg(-1) min(-1) and 75 micromol x l(-1) respectively, and in human liver HL-9 39 pmol mg(-1) x min(-1) and 70 micromol x l(-1) respectively; for the O-demethylation in HL-1 131 pmol mg(-1) min(-1) and 95 micromol x l(-1) respectively, and in HL-9 145 pmol mg(-1) min(-1) and 94 micromol x l(-1) respectively. Quinidine is for both pathways a potent inhibitor of the high-affinity site, with K(i) values ranging from 0.03 to 0.18 micromol x l(-1). Fluoxetine, norfluoxetine and paroxetine are likewise potent inhibitors, with Ki values ranging from 0.30 to 2.1 micromol x l(-1) fluvoxamine, sertraline, desmethylsertraline, citalopram and desmethylcitalopram are less potent inhibitors, with K(i) values above 10 micromol x l(-1).

CONCLUSION

The rank order of the SSRIs for inhibition of metoprolol metabolism is comparable to that reported in the literature for other CYP2D6 substrates, with fluoxetine, norfluoxetine and paroxetine being the most potent. These findings need further investigation to determine their clinical relevance.

L-PRF for increasing the width of keratinized mucosa around implants: A split-mouth, randomized, controlled pilot clinical trial

BACKGROUND

This study aims to evaluate the use of the leukocyte- and platelet-rich fibrin (L-PRF) membranes in increasing the width of the keratinized mucosa (KM) around implants.

MATERIAL AND METHODS

Eight patients in need for bilateral widening of the KM around implants in the lower jaw were recruited for a spit-mouth randomized controlled trial. At the control site, a free gingival graft (FGG) was used, whereas at the other side (test), L-PRF membranes were applied. The primary outcome was the increase in width of KM around the implants. As secondary outcomes, the postoperative pain and surgical time were assessed. The follow-up period was 6 weeks.

RESULTS

A significant increase in the total bucco-lingual width of KM in both groups was observed, with 1.3 mm ± 0.9 extra gain (P < .05) for the FGG sites. Shrinkage of the widened areas in this period was 32.1% at the test site and 23.6% at the control site. All values of the postoperative pain scores at the control site were higher than at the test site. The mean surgery time in the test and control group was 29.1 ± 4.8 and 48.1 ± 7.7 minutes, respectively.

CONCLUSION

Within the limitations of this randomized controlled trial with split mouth design, it can be concluded that L-PRF can increase the width of KM around implants. Furthermore, the use of L-PRF results in a lower surgical time with less postoperative discomfort and pain for the patients in comparison to the FGG.

A Prospective, Controlled, Multicenter Study to Evaluate the Clinical Outcome of Implant Treatment in Women with Osteoporosis/Osteopenia: 5-Year Results

The impact of osteoporosis on implant treatment is still a matter of debate in the scientific community, as it may possibly lead to higher failure rates. As long-term controlled trials are missing, the aim of this study was to verify the long-term outcome of implants placed in patients with systemic osteoporosis. Postmenopausal women in need of implants underwent bone mineral density measurements in hip and spine, using dual X-ray absorptiometry scans. Based on T-scores, they were divided into 2 groups: group O (osteoporosis group) with a T-score ≤-2 or group C (control group) with a T-score of ≥-1. Implants were placed in a 2-stage manner and loaded 4 to 8 wk after abutment surgery. Six months after loading and thereafter yearly, clinical and radiographical parameters were assessed. In total, 148 implants were placed in 48 patients (mean age: 67 y [range, 59-83]). Sixty-three implants were placed in 20 patients (group O) and 85 implants in 28 patients (group C). After 5 y, 117 implants (38 in group O and 79 in the group C) in 37 patients were assessed. Cumulative survival rate on an implant level was 96.5% (group O: 91.5%; group C: 100.0% [ P < 0.05]) and 95.7% (group O: 89.2%; group C: 100.0% [ P > 0.05]) on a patient level. The overall marginal bone-level alterations, after 5 y of loading, were -0.09 ± 0.78 mm (group O: -0.15 ± 0.50 mm; group C: -0.06 ± 0.89 mm) on an implant level and -0.09 ± 0.54 mm (group O: -0.18 ± 0.43 mm; group C: 0.06 ± 0.58 mm) on a patient level ( P > 0.05). Oral implant therapy in osteoporotic patients is a reliable treatment option with comparable osseointegration rates, implant survival, and marginal bone-level alterations after 5 y of functional loading (ClinicalTrials.gov NCT00745121).

Inhibitory control in euthymic bipolar disorder: Event related potentials during a Go/NoGo task

OBJECTIVES

Patients with bipolar disorder (BD) are reported to have difficulties with inhibition, even in a euthymic state. However, the literature on cortical activity associated with response inhibition in BD remains ambiguous. This study investigates inhibition in euthymic BD using electrophysiological measures, while controlling for effects of specific medications.

METHODS

Twenty patients with BD were compared with eighteen healthy controls on a Go/NoGo task while electroencephalogram was recorded. Behavioral and event-related potential (ERP) measurements were analyzed for the two groups. Medication effects were controlled for in the analysis.

RESULTS

Patients with BD had marginally reduced NoGo N2 amplitudes and increased NoGo P3 amplitudes compared with healthy controls when patients using benzodiazepines were excluded from the study. No behavioral differences between the groups were found.

CONCLUSIONS

Reduced NoGo N2 amplitudes in BD reflect aberrant conflict detection, an early stage of the inhibition process. In addition, increased NoGo P3 amplitudes in BD despite normal task performance reflect an overactive cortical system during a simple inhibition task.

SIGNIFICANCE

Difficulties in early stages of inhibition in BD appear to have been compensated by increased cortical activation. This study extends current knowledge regarding cortical activations relating to inhibition in BD.

Impact of local and systemic antimicrobials on leukocyte- and platelet rich fibrin: an in vitro study

The aim of this study was to evaluate the effect of local and systemic administration of antimicrobials to leukocyte- and platelet-rich fibrin (L-PRF). For part A, 16 tubes of venous blood were collected from each of eight systemically healthy subjects. Prior to blood centrifugation, 12 of the 16 tubes were injected with 0.125 ml, 0.25 ml or 0.50 ml metronidazole solution. One set of L-PRF membranes was used to assess the release of vascular endothelial growth factor AB, platelet-derived growth factor, transforming growth factor beta 1, and bone morphogenetic protein 2 at indicated time points. The metronidazole release over time by L-PRF membranes was also evaluated. The remaining L-PRF membranes were placed on the surface of agar plates inoculated with three different periodontal pathogens to determine their antibacterial activity. For part B, another six subjects were enrolled with three subjects taking 2 g amoxicillin and three subjects 500 mg metronidazole as prophylaxis prior to a periodontal treatment. Before and 2 h after consuming one of the prescribed antimicrobials, three tubes of blood were collected for preparing L-PRF membranes. These membranes were used to measure the antibacterial activity against periodontal pathogens. No statistically significant difference could be found in the release of growth factors between L-PRF membranes with and without incorporation of metronidazole solution. The release of metronidazole could be detected up to day 3, however with the highest concentration during the first 4 h. This concentration was dose dependent. The antibacterial capacity of L-PRF membranes increased significantly for both the systemic intake, and after the addition of metronidazole solution to the blood tubes before centrifugation, the latter again dose dependent. The antibacterial capacity of L-PRF against the periodontal pathogens tested can significantly be enhanced by the addition of antimicrobials, without disadvantage for the release of growth factors.

Oral implant placement and restoration by undergraduate students: clinical outcomes and student perceptions

INTRODUCTION

Universities are developing and implementing implant dentistry training to prepare dental professionals for the growing treatment needs. This study describes how implant dentistry is taught at the KU Leuven and focuses on implant-related clinical outcomes. Perspectives of participating undergraduate students are analysed with a view to improve oral implant dentistry training.

MATERIALS AND METHODS

Implant dentistry training at the KU Leuven consists of theoretical lectures, pre-clinical hands-on workshops and clinical (surgical/prosthetic) experience. Questionnaires were used to investigate the perceptions of students on the educational programme. Radiographs were taken at implant insertion, at healing abutment connection, at restoration/prosthesis insertion and after 1 and 2 years of functional loading. The marginal bone level was measured from the implant-abutment connection to the first visible bone-to-implant contact.

RESULTS

One hundred and twelve implants were placed by 56 undergraduate students (61.5% of the total students) in 56 patients. After a follow-up time of 3 years, the cumulative implant survival rate, at implant level, was 97.1%. The mean marginal bone loss after 1 and 2 years in function was 0.35 mm and 0.39 mm, respectively. Eighty percentage of students were satisfied with the training, and they considered this sufficient preparation to perform implant placement under close supervision.

CONCLUSIONS

The clinical outcome of implant treatment performed by undergraduate students under close supervision is similar to that reported by experienced clinicians/research teams. Clinical, surgical as well as restorative experience in addition to theoretical and pre-clinical training seems beneficial when implementing implant dentistry in the undergraduate programmes.

[Does good oral hygiene guarantee the maintenance of a health periodontium?]

On the last European Workshop for Periodontology, it was accepted that the prevalence of periodontitis in certain regions of Europe and USA has decreased. It remains difficult to phrase a decision concerning the prevalence of periodontitis in general. This article wants to highlight the need of a good oral hygiene and different forms of prevention (primary, secondary & tertiary) in the maintenance of a healthy periodontium. The relationship between gingivitis and tooth loss is pointed out. The prevention is described in the complexity of the periodontitis proces and it's modifying factors. When dealing with different forms of periodontitis (refractory, necrotising gingivitis and periodontitis, agressive periodontitis) prevention needs to be adjusted to the etiology and specific situation. This is also the case in peri-implantitis. This article tends to find a scientific background for oral hygiene and prevention in periodontal disease.

Instructions for the use of L-PRF in different clinical indications

Autologous platelet concentrates (APCs) have demonstrated clear benefits across various clinical applications, including alveolar ridge preservation, guided tissue regeneration, guided bone regeneration, sinus floor elevation (both lateral window approach and transcrestal technique), endodontic surgery, the treatment of medication-related osteonecrosis of the jaw bones, and periodontal plastic surgery. To ensure an optimal clinical outcome, clinicians must adhere strictly to the protocol to prepare the APCs and, especially follow evidence-based surgical guidelines, often simple but crucial, to minimize the likelihood of errors. The majority of clinical trials reported on second-generation APCs [the leukocyte- and platelet-rich fibrin (L-PRF) family, including its modifications (A-PRF, A-PRF+, CGF, T-PRF, H-PRF, etc.)]. These second-generation APCs offer additional benefits compared to the first-generation APCs, making them the preferred choice for the development of clinical recommendations. These recommendations have been formulated through a meticulous examination of the available clinical data and the clinical experience of the authors of this paper.

[Innovative methods and developments in oral care. L-PRF: from evidence to clinical use]

Leukocyte- and platelet-rich fibrin (L-PRF) is a fully autologous biomaterial made from venous blood drawn from the patient. Due to its regenerative potency, antibacterial capacity, and analgesic activity, L-PRF can be used during surgical procedures as a sole biomaterial or as a bioactive additive along with other natural and synthetic biomaterials. There is sufficient scientific evidence available for applying L-PRF for various indications. The preparation protocol of L-PRF is simple, inexpensive and not time-consuming, making it possible to implement it in the daily practice. The type of centrifuge and blood collection tubes used, the settings of the centrifuge (rotation time and force) as well as the time between the different steps in the protocol have an influence on the biological and mechanical properties of L-PRF.

[Social cognition in bipolar disorder]

BACKGROUND

Bipolar disorder is characterised by disturbed mood regulation. Recently, research has focused on cognitive deficits, including social-cognitive deficits, which have a major impact on daily functioning.

AIM

To review the recent literature on social cognition in both the symptomatic and the remission phases in bipolar disorder and to discuss the link between social cognition and psychosocial functioning.

METHOD

We reviewed the literature systematically using the most important literature databases and cross-references.

RESULTS

Deficits in social-cognitive domains such as emotion recognition and Theory of Mind become apparent during both the symptomatic and remission phases. These deficits are influenced by moderating variables such as medication use, clinical symptoms and neurocognitive deficits. Furthermore, in some recent studies these social-cognitive deficits have been linked to poorer functioning.

CONCLUSION

In bipolar disorder, social-cognitive deficits are present in different areas and are to a large extent independent of the mood phase. There is an urgent need for more research into the various cognitive domains and into the effect that these have on daily functioning in all phases of bipolar disorder.

Ten-Year Follow-Up of Oral Implants in Bone With Limited Bucco-Oral Dimensions: A Prospective Case Series

BACKGROUND

It has been suggested that 1-2 mm of bone width at the buccal and lingual aspect is required for a successful long-term implant outcome. Low levels of evidence support this minimum threshold of bone width. This prospective study aimed at evaluating the outcome of implants placed in alveolar ridges with limited bucco-oral dimensions.

MATERIALS AND METHODS

One-hundred implants (dia. 3.5 mm) were placed in 28 patients with narrow alveolar ridge dimensions (<4.5 mm width) without augmentation procedures and conventionally loaded. Intra-oral radiographs were taken at implant placement and abutment connection and at 1, 2, 3, 5 and 10 years of follow-up. At the 10-year follow-up (21 patients; 75 implants), full-mouth periodontal charting was performed, and the peri-implant keratinized tissue width and attachment type were recorded. Two calibrated periodontists analysed the peri-implant bone changes.

RESULTS

After 10 years, all implants showed successful osseointegration and a cumulative survival rate of 100%. The implants were placed 0.85 mm ± 0.89 mm subcrestally. After 10 years, the marginal bone was located 1.59 ± 2.11 mm apical to the implant shoulder. Throughout this period of follow-up, the mean annual marginal bone loss was 0.094 mm. Furthermore, 84% of implants in 72% of patients presented with bleeding on probing.

CONCLUSION

After 10 years of functional loading, implants placed in alveolar ridges with limited bucco-oral dimensions (≤4.5 mm) exhibited only minimum marginal bone loss.

[Electric toothbrushes]

In the 19th century, the first electric toothbrush was introduced. As years gone by, the design and brushhead movements have been constantly changing. Companies claim that electric toothbrushes are more efficient than manual toothbrushes. In this literature review, the importance of the different brushhead movements, brushing time and brushing force and their impact on microbiology and gingival recession is pointed out. Furthermore, the efficiency of electric toothbrushes is evaluated through the available scientific evidence.

Mitral valve replacement in infancy: haemodynamic factors

Severe mitral valve regurgitation necessitated the insertion of a prosthetic valve (Björk-Shiley no. 21) in a girl 10 months of age. Control studies after the baby had doubled her body weight showed normal haemodynamic data. It is estimated that a valve of this size should allow the expected cardiac output for a patient of 9-12 years of age. Thrombosis and tissue overgrowth may result in "recurrent" mitral stenosis long before this date. Repeated haemodynamic studies at intervals of 2-3 years are therefore indicated, since clinical signs fail to show recurrent valve stenosis; should the latter develop there is the risk of irreversible pulmonary vascular resistance.

[Dentifrices:an evaluation based on the current literature]

Toothpastes remain a frequently used auxilary in oral hygiene. Although some new components have been introduced, the base composition does not differ much between toothpaste types. Concerning toothpastes there is a thin border between cosmetics and drugs and it becomes more and more difficult for oral health care workers to prescribe the right toothpaste for the right patient. Production companies are frequently using commercial advertisements to promote their product. In this way, it's getting more and more difficult for the dentist (and patient) to find the suitable product. This literature review aims to search for scientific evidence for toothpaste components and their clinical use. In this way the review can be used as a compendium for health care workers to make the right choice in prescribing toothpastes. Furthermore all available toothpastes on the Belgian market are listed, following their composition.

Autologous platelet concentrates after third molar extraction: A systematic review

Surgical removal of impacted mandibular third molars is often followed by postoperative sequelae like pain, swelling, trismus, etc. This systematic review explored the benefits of applying different autologous platelet concentrates (APCs) in the extraction socket of third molars. For this systematic review, PubMed, EMBASE, Web of Science, and Scopus have been utilized, initially yielding 544 papers. The search was narrowed to randomized controlled trials (RCTs, n = 59) published before 2024, all comparing the outcome of applying APCs in the extraction socket of surgically removed impacted mandibular third molars with unassisted healing (blood clot). Most RCTs primarily assessed the impact of APCs on postoperative sequelae. Some RCTs looked at soft- and hard-tissue healing. Eleven studies used PRP, three PRGF, and 45 L-PRF. A detailed analysis revealed a large heterogeneity between studies rendering a meta-analysis impossible. Moreover, the risk of bias was considered high. In the majority of RCTs, the application of an APC resulted in statistically significant reductions of postoperative sequelae (lower pain intensity, lower consumption of analgesics, less postoperative edema, and a lower incidence of trismus and alveolar osteitis), as well as a faster soft tissue healing, and qualitatively and quantitatively better bone healing. A minority of studies reported significant differences in periodontal parameters distally from the second molar.