Clinical utility of fungal culture and antifungal susceptibility in cats and dogs with histoplasmosis

BACKGROUND

Culture can be used for diagnosis and antifungal susceptibility testing in animals with fungal infections. Limited information is available regarding the diagnostic performance of culture and the susceptibility patterns of Histoplasma spp. isolates.

HYPOTHESIS/OBJECTIVES

Describe the clinical utility of culture and the susceptibility patterns of Histoplasma spp. isolates causing histoplasmosis in cats and dogs.

ANIMALS

Seventy-one client-owned animals, including 33 cats and 19 dogs with proven or probable histoplasmosis.

METHODS

Culture was attempted from tissue or fluid samples. Diagnostic performance of culture, cytopathology, and antigen detection were compared with final diagnosis. Susceptibility to antifungal agents was determined for a subset (11 from dogs, 9 from cats) of culture isolates.

RESULTS

Culture had a diagnostic sensitivity of 17/33 (52%; 95% confidence interval [CI], 34%-69%) and 15/19 (79%; 95% CI, 61%-97%) and specificity of 6/6 (100%; 95% CI, 54%-100%) and 10/10 (100%; 95% CI, 69%-100%) in cats and dogs, respectively. Culture was not positive in any animal in which cytopathology and antigen testing were negative. Target drug exposure (area under the concentration curve [AUC]/minimum inhibitory concentration [MIC] >25) should be easily achieved for all isolates for itraconazole, voriconazole, or posaconazole. Five of 20 (25%) isolates had fluconazole MIC ≥32 μg/mL and achieving target drug exposure is unlikely.

CONCLUSIONS AND CLINICAL IMPORTANCE

Fungal culture did not improve diagnostic sensitivity when used with cytopathology and antigen detection. Susceptibility testing might help identify isolates for which fluconazole is less likely to be effective.

Retrospective analysis of immunosuppressive and anti-thrombotic protocols in nonassociative immune mediated hemolytic anemia in dogs

BACKGROUND

Evidence supporting the effectiveness of therapeutic protocols for nonassociative immune-mediated hemolytic anemia (na-IMHA) is weak.

HYPOTHESIS/OBJECTIVES

Investigate the efficacy of various drugs in na-IMHA.

ANIMALS

Two hundred forty-two dogs.

METHODS

Multi-institutional retrospective study (2015-2020). Immunosuppressive effectiveness was determined by time to packed cell volume (PCV) stabilization and duration of hospitalization through analysis by mixed model linear regression. Occurrence of disease relapse, death, and antithrombotic effectiveness, were analyzed using mixed model logistic regression.

RESULTS

Use of corticosteroids vs a multi-agent protocol had no effect on time to PCV stabilization (P = .55), duration of hospitalization (P = .13), or case fatality (P = .06). A higher rate of relapse (P = .04; odds ratio: 3.97; 95% confidence interval [CI]: 1.06-14.8) was detected in dogs receiving corticosteroids (11.3%) during follow-up (median: 28.5 days, range: 0-1631 days) compared to multiple agents (3.1%) during follow up (median: 47.0 days, range: 0-1992 days). When comparing drug protocols, there was no effect on time to PCV stabilization (P = .31), relapse (P = .44), or case fatality (P = .08). Duration of hospitalization was longer, by 1.8 days (95% CI: 0.39-3.28 days), for the corticosteroid with mycophenolate mofetil group (P = .01) compared to corticosteroids alone. Use of clopidogrel vs multiple agents had no effect on development of thromboses (P ≥ .36).

CONCLUSIONS AND CLINICAL IMPORTANCE

Addition of a second immunosuppressive agent did not alter immediate outcome measures but might be associated with a reduction in relapse. Use of multiple antithrombotic agents did not reduce incidence of thrombosis.

Effect of washing units of canine red blood cells on storage lesions

Background

In humans, washing stored blood products before transfusion reduces storage lesions and incidence of transfusion reactions, but the effectiveness of washing canine blood is unknown.

Objectives

The objective was to determine if manually washing units of stored blood would reduce storage lesions without adversely affecting erythrocytes. We hypothesized that washing stored units would reduce concentrations of storage lesions and cause minimal erythrocyte damage.

Animals

Eight healthy research dogs.

Methods

Repeated measure cohort study. Units of whole blood were stored for 28 days and washed 3 times with 0.9% NaCl. Blood samples were collected before and after storage, after each wash, and after being held at a simulated transfusion temperature. Variables measured included CBC variables, blood gas analysis, erythrocyte morphology, mean corpuscular fragility (MCF), and eicosanoid concentrations. A Friedman's test was used to evaluate changes in variables (P < .05 was considered significant).

Results

After the first wash, compared to values after storage, there was a significant decrease in potassium (4.3 mmol/L [4.0‐4.7] to 1.2 mmol/L [1‐1.6]; P < .0001, median [range]), lactate (1.45 mmol/L [1.07‐1.79] to 0.69 mmol/L [0.39‐0.93]; P = .002), and partial pressure carbon dioxide (102 mm Hg [80.2‐119.2] to 33.7 mm Hg [24.5‐44.5]; P < .0001), and increase in MCV (69.3 fL [65.7‐72.3] to 74 fL [69.6‐79.5]; P = .0003), and MCF (0.444 fL [0.279‐0.527] to 0.491 fL [0.43‐0.616]; P = .0006).

Conclusions and Clinical Importance

A single wash of stored whole blood significantly reduces most extracellular storage lesions, and additional washing might cause hemolysis.

Effects of leukoreduction on N-methylhistamine concentration in stored units of canine whole blood

OBJECTIVE

To determine the effects of leukoreduction on N-methylhistamine (NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature (approx 22 °C) to simulate temperature conditions during transfusion.

ANIMALS

8 healthy adult Walker Hounds.

PROCEDURES

A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 °C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage.

RESULTS

Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction.

CONCLUSIONS AND CLINICAL RELEVANCE

Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.

Effects of pentoxifylline on canine platelet aggregation

BACKGROUND

Pentoxifylline can decrease platelet function in humans, but the anti-platelet effects of pentoxifylline in dogs is unknown. The addition of a luciferin-luciferase reagent during platelet aggregometry can induce a dose-dependent potentiation of platelet aggregation.

OBJECTIVE

To determine if exposure to pentoxifylline, without the addition of a luciferin-luciferase reagent during aggregometry, causes canine platelet dysfunction. Our hypotheses were that pentoxifylline would inhibit platelet function, and that the addition of a luciferin-luciferase reagent would obscure detection of pentoxifylline-induced platelet dysfunction as measured via aggregometry.

METHODS

Seven healthy Walker hound dogs. Platelet-rich plasma (PRP) and whole blood were treated for 30 minutes with pentoxifylline: 0 (control), 1 and 2 μg/mL. The platelet aggregation was determined using optical (maximum amplitude) and impedance (ohms) aggregometry using collagen as the agonists, with and without a luciferin-luciferase reagent. Four samples were analysed per concentration and the results were averaged.

RESULTS

Based on optical aggregometry, there was no difference (p = 0.964) in the mean maximum amplitude at any pentoxifylline concentration, with and without the luciferin-luciferase reagent. During impedance aggregometry, the addition of a luciferin-luciferase reagent was associated with significantly (p < 0.001) greater platelet aggregation in response to a collagen agonist, regardless of the presence or absence of pentoxifylline.

CONCLUSIONS

Pentoxifylline does not exert an in vitro anti-platelet effect on canine platelet aggregation when collagen is used as an agonist, but it is unknown if long-term oral drug administration will inhibit platelet aggregation. The addition of a luciferin-luciferase reagent during platelet aggregometry can artificially enhance canine platelet aggregation.

Effects of oral administration of 5 immunosuppressive agents on activated T-cell cytokine expression in healthy dogs

BACKGROUND

Dogs are often adminstered >1 immunosuppressive medication when treating immune-mediated diseases, and determining whether these different medications affect IL-2 expression would be useful when performing pharmacodynamic monitoring during cyclosporine therapy.

HYPOTHESIS/OBJECTIVES

To determine the effects of 5 medications (prednisone, cyclosporine, azathioprine, mycophenolate mofetil, and leflunomide) on activated T-cell expression of the cytokines IL-2 and interferon-gamma (IFN-γ).

ANIMALS

Eight healthy dogs.

METHODS

Randomized, cross-over study comparing values before and after treatment, and comparing values after treatment among drugs. Dogs were administered each drug at standard oral doses for 1 week, with a washout of at least 21 days. Activated T-cell expression of IL-2 and IFN-γ mRNA was measured by quantitative reverse transcription polymerase chain reaction. Blood drug concentrations were measured for cyclosporine, mycophenolate, and leflunomide metabolites.

RESULTS

Least squares means (with 95% confidence interval) before treatment for IL-2 (2.91 [2.32-3.50] ΔCt) and IFN-γ (2.33 [1.66-3.00 ΔCt]) values were significantly lower (both P < .001) than values after treatment (10.75 [10.16-11.34] and 10.79 [10.11-11.46] ΔCt, respectively) with cyclosporine. Similarly, least squares means before treatment for IL-2 (1.55 [1.07-2.02] ΔCt) and IFN-γ (2.62 [2.32-2.92] ΔCt) values were significantly lower (both P < .001) than values after treatment (3.55 [3.06-4.00] and 5.22 [4.92-5.52] ΔCt, respectively) with prednisone. Comparing delta cycle threshold values after treatment among drugs, cyclosporine was significantly different than prednisone (IL-2 and IFN-γ both P < .001), with cyclosporine more suppressive than prednisone.

CONCLUSIONS AND CLINICAL IMPORTANCE

Prednisone and cyclosporine both affected expression of IL-2 and IFN-γ, suggesting that both have the ability to influence results when utilizing pharmacodynamic monitoring of cyclosporine treatment.

Effects of Aspirin and Prednisone on Platelet Function and Thromboxane Synthesis in Healthy Dogs

Glucocorticoid administration is a risk factor for thromboembolism in hypercoagulable dogs, and it is unknown if aspirin counteracts glucocorticoid-induced hypercoagulability. The objective was to determine the effects of sustained aspirin and prednisone administration on platelet function and thromboxane synthesis. Our hypothesis was that aspirin would consistently inhibit platelet function and thromboxane synthesis when administered with or without prednisone. In 24 healthy dogs, platelet aggregometry and urine 11-dehydro-thromboxane-B₂ (11-dTXB₂)-to-creatinine ratios were measured on days 0, 14, and 28. Dogs were administered placebos, aspirin (2 mg/kg/d), prednisone (2 mg/kg/d), or prednisone/aspirin combination therapy PO for 28 days in a randomized double-blinded study. Aspirin response was based on a >25% reduction in platelet aggregation compared to pre-treatment values. Results were compared using mixed model, split-plot repeated measures ANOVAs. P < 0.05 was considered significant. AUC differed significantly by time [F_(2,40) = 10.2, P < 0.001] but not treatment or treatment-by-time. On day 14, 2 dogs were aspirin responders (aspirin, 1; placebo, 1). On day 28, 3 dogs were aspirin responders (aspirin, 2; prednisone/aspirin, 1). Urine 11-dTXB₂-to-creatinine ratios differed significantly by group [F_(3,20) = 3.9, P = 0.024] and time [F_(2,40) = 8.7, P < 0.001), but not treatment-by-time. Post-hoc analysis revealed significant differences between aspirin and placebo groups (P=0.008), aspirin and prednisone/aspirin groups (P = 0.030), and placebo and prednisone groups (P = 0.030). In healthy dogs, sustained aspirin, prednisone, and combination therapy do not inhibit platelet aggregation, and when used as individual therapies, aspirin and prednisone decreased thromboxane synthesis. Additional studies using varied platelet function methodologies in hypercoagulable dogs are necessary.

Coagulation factor activity in units of leukoreduced and nonleukoreduced canine fresh-frozen plasma

OBJECTIVE

To evaluate coagulation factors in units of leukoreduced (LR) and nonleukoreduced (non-LR) canine fresh-frozen plasma (cFFP).

ANIMALS

8 healthy research dogs.

PROCEDURES

In a crossover study, dogs were randomly assigned to 1 of 2 groups from which blood was collected and either did or did not undergo leukoreduction. After a recovery period of ≥ 28 days, the dogs were switched between protocols. After each collection, blood samples were centrifuged, and cFFP was stored frozen for later comparative analysis of coagulation factors, antithrombin, and protein C activities (reported as comparative percentages of the corresponding activities determined in a canine pooled plasma standard); prothrombin and activated partial thromboplastin times; and fibrinogen concentration.

RESULTS

There were no significant differences detected between results for LR cFFP, compared with those for non-LR cFFP.

CONCLUSIONS AND CLINICAL RELEVANCE

Although there was variation among residual activities of coagulation factors in LR and non-LR cFFP, the variations and differences were considered unlikely to impact the efficacy of LR cFFP transfused for coagulation factor replacement in dogs. However, owing to the small sample size and high variability of results in the present study, additional research with a larger sample size is required for definitive conclusions on the effects of leukoreduction on coagulation factors in cFFP and to develop treatment guidelines for LR cFFP use in dogs with congenital and acquired coagulopathies.

Assessment of erythrocyte damage and in-line pressure changes associated with simulated transfusion of canine blood through microaggregate filters

OBJECTIVE

To determine whether passage of whole blood through a microaggregate filter by use of a syringe pump would damage canine erythrocytes.

SAMPLE

Blood samples obtained from 8 healthy client-owned dogs.

PROCEDURES

Whole blood was passed through a standard microaggregate filter by use of a syringe pump at 3 standard administration rates (12.5, 25, and 50 mL/h). Prefilter and postfilter blood samples were collected at the beginning and end of a simulated transfusion. Variables measured at each time point included erythrocyte osmotic fragility, mean corpuscular fragility, RBC count, hemoglobin concentration, RBC distribution width, and RBC morphology. In-line pressure when blood passed through the microaggregate filter was measured continuously throughout the simulated transfusion. After the simulated transfusion was completed, filters were visually analyzed by use of scanning electron microscopy.

RESULTS

Regardless of administration rate, there was no significant difference in mean corpuscular fragility, RBC count, hemoglobin concentration, or RBC distribution width between prefilter and postfilter samples. Additionally, there were no differences in in-line pressure during the simulated transfusion among administration rates. Echinocytes were the erythrocyte morphological abnormality most commonly observed at the end of the transfusion at administration rates of 12.5 and 25 mL/h.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that regardless of the administration rate, the microaggregate filter did not alter fragility of canine RBCs, but may have altered the morphology. It appeared that the microaggregate filter would not contribute to substantial RBC damage for transfusions performed with a syringe pump.

Effects of cyclosporine on feline lymphocytes activated in vitro

Cyclosporine A (CsA) is a calcineurin inhibitor that is known to decrease lymphocyte expression of NFAT-regulated cytokines in humans, dogs and cats, and thereby depress lymphocyte function. Less is known about the effects of CsA on lymphocytes in cats than in other species. Peripheral blood mononuclear cells (PBMCs) were isolated from 6 healthy cats. PBMCs were exposed to i) no treatment, ii) 5 μg/ml concavalin A (ConA), iii) 500 ng/ml CsA and iv) 5 μg/ml ConA and 500 ng/ml CsA. The effects of CsA on cell proliferation were assessed via live and necrotic cell counts from day 1 to day 6. Additionally, flow cytometry was utilized to determine the effect of CsA on apoptosis in feline lymphocytes at day 1 and day 5. ConA exposure resulted in increases in cell counts from day 1 to 6, peaking at day 5. CsA inhibited cell proliferation, indicated via decreased live lymphocyte cell counts in the cell cultures exposed to ConA and CsA, compared to the cell cultures exposed to ConA only. Furthermore, CsA induced early and late apoptotic changes in feline PBMCs. Differences in these responses may influence an individual cat's response to cyclosporine therapy.

Technique for Evaluation of Gravity-Assisted Esophageal Transit Characteristics in Dogs with Megaesophagus

Movement of food material in the esophagus during upright feeding in dogs with megaesophagus (ME) is poorly characterized. A standardized contrast videofluoroscopy technique was used to evaluate esophageal transit characteristics in dogs with ME while in an upright position. Twelve dogs with ME (congenital, acquired idiopathic, or secondary to myasthenia gravis) were placed in an upright position using Bailey chairs and given liquid barium, canned food meatballs, and their normal diet consistency if different than meatballs. Passage of ingesta was videofluoroscopically evaluated by direct observation and change in ingesta area as determined by manual tracing or barium column product calculations. Significant individual variation was seen. Complete esophageal clearance of liquid was seen in four dogs, and complete clearance of meatballs in three dogs, with a median time of 5 min for both. Two of seven dogs fed a slurry diet had complete clearance by 10 min. No significant difference was found between area calculated via tracing or barium column product. Based on imaging results, alterations in food consistency, duration upright, or medication were recommended for nine dogs. In dogs with ME accustomed to a Bailey chair, contrast videofluoroscopy was technically straightforward and allowed for more specific physician-guided management recommendations.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 4-Refining and monitoring antithrombotic therapies

OBJECTIVES

To systematically review the evidence for therapeutic monitoring of antithrombotic drugs in small animals, develop guidelines regarding antithrombotic monitoring, and identify knowledge gaps in the field.

DESIGN

First, a standardized, systematic literature review was conducted to address predefined PICO (Population/Patient, Intervention, Control, Outcome) questions, with categorization of relevant articles according to level of evidence and quality. Preliminary guidelines were developed by PICO worksheet authors and the domain chair. Thereafter, a Delphi-style survey was used to develop consensus on guidelines regarding therapeutic monitoring of antithrombotics in dogs and cats.

SETTING

Academic and referral veterinary medical centers.

RESULTS

PICO questions regarding the utility of therapeutic monitoring were developed for 6 different antithrombotic drugs or drug classes, including aspirin, clopidogrel, warfarin, unfractionated heparin, the low molecular weight heparins, and rivaroxaban, The majority of the literature pertaining to therapeutic monitoring of antithrombotic drugs was either performed in experimental animal models of disease or involved studies of drug pharmacokinetics and pharmacodynamics in healthy laboratory animals. There was a paucity of high level of evidence studies directly addressing the PICO questions, which limited the strength of recommendations that could be provided. The final guidelines recommend that therapeutic monitoring should be performed when using warfarin or unfractionated heparin in dogs and cats at risk of thrombosis. There is insufficient evidence to make strong recommendations for therapeutic monitoring of aspirin or low molecular weight heparin in dogs and cats at this time.

CONCLUSIONS

As in other CURATIVE domains, significant knowledge gaps were highlighted, indicating the need for substantial additional research in this field. Ongoing investigation of the role of therapeutic monitoring of antithrombotic therapies will undoubtedly facilitate improved outcomes for dogs and cats at risk of thrombosis.

Effects of immunosuppressive agents on the hemostatic system in normal dogs

Background

In dogs, the effects of immunosuppressive medications on hemostasis are not well known.

Hypothesis/Objectives

The objective was to determine the effects of immunosuppressive medications on primary and secondary hemostasis. Our hypothesis was that cyclosporine and prednisone would increase markers of hypercoagulability and thromboxane synthesis, while azathioprine, mycophenolate mofetil, and leflunomide would have minimal effects on hemostasis.

Animals

Eight healthy dogs.

Methods

A randomized, cross‐over study used aggregometry, the PFA‐100 platelet function analyzer, viscoelastometry, platelet count, and prothrombin and activated partial thromboplastin times to evaluate hemostasis during the administration of prednisone, azathioprine, cyclosporine, mycophenolate mofetil, and leflunomide for 1 week each at standard oral doses. Urine 11‐dehydro‐thromboxane‐B₂ (11‐dTXB₂) and 6‐keto‐prostaglandin‐F_1α (6‐keto‐PGF_1α) concentrations, normalized to urine creatinine concentration, were measured.

Results

The aggregometry amplitude decreased from 51 ± 21 to 27 ± 14 (P = .002) during leflunomide treatment (ADP activation), but there were no differences in amplitude (P = .240) for any medications when platelets were activated with collagen. For all medications, there were no significant differences in viscoelastometry indices (ACT, P = .666; ClotRate, P = .340; and platelet function, P = .411) and platelet count (P = .552). Compared with pretreatment values, urinary 11‐dTXB₂‐to‐creatinine ratio increased (P = .001) after drug administration (from 3.7 ± 0.6 to 5.6 ± 1.1). Cyclosporine was associated with an increase (P < .001) in the 6‐keto‐PGF_1α‐to‐creatinine ratio (from 10.3 ± 4.6 to 22.1 ± 5.3).

Conclusions and Clinical Importance

Most immunosuppressive drugs do not enhance platelet function or coagulation in healthy dogs, suggesting that these medications might not predispose hypercoagulable dogs to thromboembolism. The results of our study need to be correlated with the clinical outcomes of hypercoagulable dogs.

Learning outcomes: Exploring implications of adopting a different level of detail

INTRODUCTION

Outcome-based programmes provide a framework to support educators and learners in understanding content and end points within taught courses. Management of these outcomes in the Dental Degree at Newcastle University has been a challenge in relation to quality assurance and enhancement, having over 1500 detailed student-level outcomes (SLO). This research aimed to explore the implications of adopting a more superficial "course" level of outcome (CLO), when reviewed against a reference set of external LO requirements.

MATERIALS AND METHODS

A purposive sample of five courses within the undergraduate dental programme was selected. The mapping of both SLOs and CLOs was reviewed in relation to their total number and the mapping connections to the reference outcomes.

RESULTS

There was a mean reduction of 79% in outcomes when comparing SLOs to CLOs. The number of mapping connections between CLOs and the reference set reduced in three courses and increased in two, when compared to SLOs.

DISCUSSION

From a purely numerical perspective, changing the detail of learning outcomes has led to a change in mapping connections. As the delivered curriculum has remained unchanged, this demonstrates a potential impact of differing interpretations of learning outcomes. Further review of learning outcomes in relation to the domains categorised within the reference outcome document suggested more mapping links were obtained in clinically focused courses than academic or theoretical courses.

CONCLUSION

A demonstrable impact in mapping connections was observed when the detail within the learning outcomes was changed. This has implications for programme leaders in structuring LOs for a curriculum.

Evaluation of SNAP cPL, Spec cPL, VetScan cPL Rapid Test, and Precision PSL Assays for the Diagnosis of Clinical Pancreatitis in Dogs

BACKGROUND

The sensitivity, specificity, and agreement of 4 diagnostic assays (SNAP canine pancreatic lipase (cPL), specific cPL (Spec cPL), VetScan cPL Rapid Test, and Precision PSL) for pancreatitis in dogs have not been directly compared.

HYPOTHESIS/OBJECTIVES

To determine the level of agreement among each of the 4 assays and a clinical suspicion score, level of agreement among the assays, and sensitivity and specificity of each assay in a clinically relevant patient group.

ANIMALS

Fifty client-owned dogs with clinical signs of gastrointestinal disease.

METHODS

Prospective study. History, physical examination, complete blood count, serum biochemistry, abdominal ultrasound examination, and the 4 diagnostic assays for pancreatitis were performed. Intraclass correlation coefficients (ICC) were used to determine the level of agreement between each assay and a clinical suspicion score determined by a panel of 5 board-certified veterinary internists.

RESULTS

The ICC between the clinical suspicion score and the 4 assays were SNAP cPL, 0.61; Spec cPL, 0.68; VetScan cPL Rapid Test, 0.68; and Precision PSL, 0.60. The sensitivities of the assays ranged from 73.9 to 100.0%, whereas the specificities were SNAP cPL, 71.1-77.8%; Spec cPL, 74.1-81.1%; VetScan cPL Rapid Test, 76.9-83.8%; and Precision PSL, 64.0-74.3%.

CONCLUSIONS AND CLINICAL IMPORTANCE

A good to excellent level of agreement was demonstrated among the 4 assays. The previously unreported sensitivity and specificity of the VetScan cPL Rapid Test were 73.9-83.3% and 76.9-83.8%, respectively. Results of any of the 4 diagnostic assays alone, in the absence of supporting clinical findings, are insufficient to establish a diagnosis of clinical pancreatitis in dogs.

Virtual courses: enhancing a curriculum

INTRODUCTION

Providers of education programmes are required to demonstrate to students, staff and external regulators the content of the programme and how this aligns to key outcomes. Whilst many programme themes are straightforward to illustrate, other integral themes prove challenging to demonstrate independently.

INNOVATION

A virtual course takes elements within the current programme relating to a specific theme, repackages and maps them to provide clear signposting by highlighting each occasion the theme is taught, experienced and assessed. The individual elements remain within their current course, so there is no disruption to the established curriculum, but there is an enhancement in terms of transparently displaying linkages within a theme.

DISCUSSION

Using the concept of virtual courses we have found we can respond to new initiatives and requirements of external regulators, as well as providing improved signposting for staff and students. This can be undertaken without the need to redesign a whole curriculum.

CONCLUSION

In well-designed and currently effective curricula, we would like to recommend that virtual course development can enhance programme transparency, demonstrate external regulatory requirements and promote quality assurance without disruption to current content.

Effects of Leukoreduction and Storage on Erythrocyte Phosphatidylserine Expression and Eicosanoid Concentrations in Units of Canine Packed Red Blood Cells

Background

Storage of canine packed red blood cells (pRBCs) can increase erythrocyte phosphatidylserine (PS) expression and eicosanoid concentrations.

Hypothesis/Objectives

To determine the effects of leukoreduction on erythrocyte PS expression and eicosanoid concentrations in stored units of canine pRBCs. Our hypothesis was that leukoreduction would decrease PS expression and eicosanoid concentrations.

Animals

Eight healthy dogs.

Methods

In a cross‐over study, units of whole blood were leukoreduced (LR) or non‐LR and stored (10 and 21 days) as pRBCs. Samples were collected at donation, and before and after a simulated transfusion. PS expression was measured by flow cytometry, and concentrations of arachidonic acid (AA), prostaglandin F_2α (PGF_2α), prostaglandin E₂ (PGE₂), prostaglandin D₂ (PGD₂), thromboxane B₂ (TXB₂), 6‐keto‐prostaglandin F_1α (6‐keto‐PGF_1α), and leukotriene B₄ (LTB₄) were quantified by liquid chromatography–mass spectrometry.

Results

There was no change in PS expression during leukoreduction, storage, and simulated transfusion for non‐LR and LR units. Immediately after leukoreduction, there was a significant increase in TXB₂ and PGF_2α concentrations, but during storage, these eicosanoids decreased to non‐LR concentrations. In both LR and non‐LR units, 6‐keto‐PGF_1α concentrations increased during storage and simulated transfusion, but there was no difference between unit type. There was no difference in AA, LTB₄, PGE₂, and PGD₂ concentrations between unit types.

Conclusions and Clinical Importance

Leukoreduction, storage, and simulated transfusion do not alter erythrocyte PS expression. Leukoreduction causes an immediate increase in concentrations of TXB₂ and PGF_2α, but concentrations decrease to non‐LR concentrations with storage. Leukoreduction does not decrease the accumulation of 6‐keto‐PGF_1α during storage.

Evaluation of eicosanoid concentrations in stored units of canine packed red blood cells

OBJECTIVE To evaluate eicosanoid concentrations in freshly prepared canine packed RBCs (PRBCs) and to assess changes in eicosanoid concentrations in PRBC units over time during storage and under transfusion conditions. DESIGN Prospective study. SAMPLE 25 plasma samples from 14 healthy Greyhounds. PROCEDURES Plasma samples were obtained during PRBC preparation (donation samples), and the PRBC units were then stored at 4°C until used for transfusion (≤ 21 days later; n = 17) or mock transfusion if expired (22 to 24 days later; 8). Immediately prior to use, 100 mL of saline (0.9% NaCl) solution was added to each unit and a pretransfusion sample was collected. A posttransfusion sample was collected after transfusion or mock transfusion. Concentrations of arachidonic acid, prostaglandin (PG) F_2α, PGE₂, PGD₂, thromboxane B₂, 6-keto-PGF_1α, and leukotriene B₄ were measured by liquid chromatography-mass spectrometry and analyzed statistically. RESULTS Median arachidonic acid concentration was significantly decreased in posttransfusion samples, compared with the concentration in donation samples. Median PGF_2α, 6-keto-PGF_1α, and leukotriene B₄ concentrations were significantly increased in pretransfusion samples, compared with those in donation samples. Median PGF_2α, thromboxane B₂, and 6-keto-PGF_1α concentrations were significantly increased in posttransfusion samples, compared with those in pretransfusion samples. Duration of PRBC storage had significant associations with pretransfusion and posttransfusion arachidonic acid and thromboxane B₂ concentrations. CONCLUSIONS AND CLINICAL RELEVANCE Concentrations of several proinflammatory eicosanoids increased in PRBC units during storage, transfusion, or both. Accumulation of these products could potentially contribute to adverse transfusion reactions, and investigation of the potential association between eicosanoid concentrations in PRBCs and the incidence of transfusion reactions in dogs is warranted.

Cost-effectiveness of Mandibular Two-implant Overdentures and Conventional Dentures in the Edentulous Elderly

Implementation of new therapies is usually governed by financial considerations, so efficacy studies should also include cost comparisons. The cost and effectiveness of mandibular conventional dentures (CD, n = 30) and two-implant overdentures (IOD, n = 30) were compared in elderly subjects. Effectiveness (Oral Health Impact Profile, OHIP-20) and cost were measured up to one year post-treatment. Data for subsequent years were estimated by the Delphi method. Using an average life expectancy of 17.9 years, the equalized annual costs (in Canadian dollars) were $399 for CD and $625 for IOD (p < 0.001), and the equalized annual values for the outcome (OHIP-20) were 47.0 for CD and 31.3 for IOD treatment (p < 0.05). These values translate into a yearly additional cost for IOD treatment of $14.41 per OHIP-20 point. These results are key to the implementation of programs to provide this form of therapy for edentulous adults.

Nutrition Counseling Increases Fruit and Vegetable Intake in the Edentulous

Edentulous denture-wearers eat fewer fruits and vegetables than do comparable dentate individuals. Improved chewing ability with new dentures has resulted in little dietary improvement, suggesting that dietary intervention is necessary. The objective of this randomized controlled trial was to have a positive impact upon dietary behavior of patients receiving replacement complete dentures through a tailored dietary intervention. Readiness to change diet (Stage of Change), intake of fruits, vegetables, and nutrients, and chewing ability were assessed pre-and 6 weeks post-intervention. The intervention group (n = 30) received two dietary counseling sessions; the control group (n = 28) received current standard care. Perceived chewing ability significantly increased in both groups. There was significantly more movement from pre-action into action Stages of Change in the intervention group, who had a greater increase in fruit/vegetable consumption (+209 g/d) than did the control group (+26 g/d) (P = 0.001). Tailored dietary intervention contemporaneous with replacement dentures can positively change dietary behavior.

Time to Survival for the Restoration of the Shortened Lower Dental Arch

Removable partial dentures may adversely affect remaining tissues and have a low prevalence of use. This randomized controlled trial was designed to compare the time to survival of cantilever resin-bonded fixed partial dentures and conventional removable partial dentures to restore shortened lower dental arches. We randomly allocated 25 male and 35 female patients (median age, 67 years) to fixed or removable partial denture groups of 30 persons, matched for age and sex. Survival of the prostheses was assessed, based on listed criteria, at each review or when problems arose. Although the removable partial denture group required rather more maintenance visits, the difference in survival rates was not statistically significant (hazard ratio = 0.59, with 95% CI 0.27, 1.29). In the absence of significant differences in five-year survival, the reported advantages of fixed partial dentures, including reduced maintenance frequency, offer positive support for the use of resin-bonded fixed partial dentures.

Effects of Firocoxib, Flunixin Meglumine, and Phenylbutazone on Platelet Function and Thromboxane Synthesis in Healthy Horses

OBJECTIVE

Determine the effects of nonsteroidal anti-inflammatory drugs (NSAID) on platelet function and thromboxane synthesis immediately after drug administration and following 5 days of NSAID administration in healthy horses.

STUDY DESIGN

Randomized cross-over study.

ANIMALS

Healthy adult horses (n=9; 6 geldings and 3 mares).

METHODS

Horses received either flunixin meglumine (1.1 mg/kg IV every 12 hours), phenylbutazone (2.2 mg/kg IV every 12 hours), or firocoxib (loading dose of 0.27 mg/kg IV on day 1, then 0.09 mg/kg IV every 24 hours for 4 days) for a total of 5 days. Blood samples were collected prior to drug administration (day 0), 1 hour after initial NSAID administration (day 1), and then 1 hour post-NSAID administration on day 5. Platelet function was assessed using turbidimetric aggregometry and a platelet function analyzer. Serum thromboxane B₂ concentrations were determined by commercial ELISA kit. A minimum 14 day washout period occurred between trials.

RESULTS

At 1 hour and 5 days postadministration of firocoxib, flunixin meglumine, or phenylbutazone, there was no significant effect on platelet aggregation or function using turbidimetric aggregometry or a platelet function analyzer. There was, however, a significant decrease in thromboxane synthesis at 1 hour and 5 days postadministration of flunixin meglumine and phenylbutazone that was not seen with firocoxib.

CONCLUSION

Preoperative administration of flunixin meglumine, phenylbutazone, or firocoxib should not inhibit platelet function based on our model. The clinical implications of decreased thromboxane B₂ synthesis following flunixin meglumine and phenylbutazone administration are undetermined.

Anticoagulant effects of inhaled unfractionated heparin in the dog as determined by partial thromboplastin time and factor Xa activity

OBJECTIVE

To evaluate the anticoagulant effects of inhaled heparin in dogs.

DESIGN

This study was conducted in 3 phases. In phase 1, bronchoalveolar lavage fluid (BALf) was collected to generate an in vitro calibration curve to relate heparin concentration to the activated partial thromboplastin time (aPTT). In phase 2, heparin was administered via nebulization to determine the threshold dose needed to prolong systemic aPTT. In phase 3, the local anticoagulant activity of inhaled heparin was determined by measurement of BALf anti-Xa activity and aPTT.

SETTING

University teaching hospital.

ANIMALS

Six healthy intact female Walker Hounds were used in this study. Two dogs were used for each phase.

INTERVENTIONS

Inhaled unfractionated sodium heparin was administered in doses ranging from 50,000 to 200,000 IU.

RESULTS

In vitro addition of heparin to BALf caused a prolongation in aPTT. Inhaled heparin at doses as high as 200,000 IU failed to prolong systemic aPTT, and a threshold dose could not be determined. No significant local anticoagulant effects were detected.

CONCLUSIONS

Even at doses higher than those known to be effective in people, inhaled heparin appears to have no detectable local or systemic anticoagulant effects in dogs with the current delivery method.

EFFECT OF LIPOSOMAL CLODRONATE-DEPENDENT DEPLETION OF PROFESSIONAL ANTIGEN PRESENTING CELLS ON NUMBERS AND PHENOTYPE OF CANINE CD4+CD25+FOXP3+ REGULATORY T CELLS

Regulatory T cells (Tregs) are known to control autoreactivity during and subsequent to the development of the peripheral immune system. Professional antigen presenting cells (APCs), dendritic cells (DCs) and monocytes, have an important role in inducing Tregs. For the first time, this study evaluated proportions and phenotypes of Tregs in canine peripheral blood depleted of professional APCs, utilizing liposomal clodronate (LC) and multicolor flow cytometry analysis. Our results demonstrate that LC exposure promoted short term decreases followed by significant increases in the proportions or absolute numbers of CD4⁺CD25⁺FOXP3⁺ Tregs in dogs. In general, the LC-dependent Treg fluctuations were similar to the changes in the levels of CD14⁺ monocytes in Walker hounds. However, the proportions of monocytes showed more dramatic changes compared to the proportions of Tregs that were visually unchanged after LC treatment over the study period. At the same time, absolute Treg numbers showed, similarly to the levels of CD14⁺ monocytes, significant compensatory gains as well as the recovery during the normalization period. We confirm the previous data that CD4⁺ T cells with the highest CD25 expression were highly enriched for FOXP3. Furthermore, for the first time, we report that CD4⁺CD25^lowFOXP3⁺ is the major regulatory T cell subset affected by LC exposure. The increases within the lowest CD25 expressers of CD4⁺FOXP3⁺ cells together with compensatory gains in the proportion of CD14⁺ monocytes during compensatory and normalization periods suggest the possible direct or indirect roles of monocytes in active recruitment and generation of Tregs from naïve CD4⁺ T cells.

Are implant supported overdentures too complex to be included in the undergraduate curriculum?

To widen the availability of implant supported mandibular overdentures, their inclusion in the undergraduate clinical training curriculum has been encouraged. The aim was to determine whether implant supported mandibular overdentures provided by undergraduates could achieve similar levels of improvement in patient satisfaction and quality of life as previously demonstrated by experienced prosthodontists. Nineteen patients were treated by Stage 3 undergraduate students at Newcastle University, School of Dental Sciences. Changes between pre-treatment and 3 month post-treatment satisfaction and oral health related quality of life suggest dental undergraduates achieve similar levels of improvement as experienced prosthodontists.

Embedding implant dentistry into the undergraduate dental curriculum

This article represents the consensus from a meeting of the British Society of Prosthetic Dentistry's Education Group which met to discuss implant dentistry at the undergraduate student level. The consensus recognises the need to embed the teaching of implant supported prostheses if such a treatment modality is to be widely practised after graduation. This short article makes some recommendations as well as detailing some challenges and barriers that need to be overcome if implant dentistry is to be successfully embedded in an undergraduate dental curriculum.

Facilitation of implant provision in primary care

OBJECTIVE

To investigate primary care practitioner participation in implant-supported mandibular overdenture (ISOD) provision.

DESIGN

Postal questionnaire.

SETTING

Primary dental care, North East England 2007.

SUBJECTS AND METHODS

Two hundred and ninety-five practitioners in North East England were sent questionnaires presenting a case-based scenario of a patient unable to manage a lower denture on an atrophic ridge. The questionnaire led them through the facilitation stages of ISOD provision, asking them to state their anticipated level of participation at each stage. Demographic details were also collected.

RESULTS

Two hundred and seventeen responses were received (74%). Most practitioners would consider the option of provision of ISODs (89%) in this case and all who considered would discuss the option with the patient. Of those offering to facilitate treatment, 66% (122/184) would never deliver themselves, with the majority (60%, 111/184) referring within primary care. Statistical analysis showed associations between demographics and behaviour.

CONCLUSIONS

The majority of practitioners in this study area would facilitate ISOD provision in this case. Practitioners who are male and working in a practice where a framework for the provision of implants already exists are most likely to facilitate provision and/or provide an ISOD within primary care.

Perceived chewing ability and intake of fruit and vegetables

Edentulous individuals have reduced chewing ability and lower fruit and vegetable consumption compared with dentate individuals. It has been suggested that the two are causally related. However, psychosocial factors such as attitude, self-identity, and knowledge of recommendations are predictive of intake in non-edentulous persons. The aims of this study were to: determine if perceived chewing ability was predictive of fruit and vegetable intake; explore the predictive ability of knowledge, attitude, and self-identity; and compare intake between edentulous and dentate individuals. Full denture-wearing (N = 79) and dentate persons (N = 52) completed a three-day food diary. Perceived chewing ability, sociodemographic, and psychosocial factors were assessed via self-administered questionnaire. The dentate persons consumed significantly more fruit and vegetables, but differences were not significant when juices were excluded. Perceived chewing ability explained approximately 4% variance in intake. Attitude, self-identity, and knowledge explained a further approximately 20%. If the diet of denture-wearers is to be improved, psychosocial factors, as well as perceived chewing ability, must be addressed.

Change in cardiovascular risk status after dental clearance

There is considerable debate over the relationship between periodontal and cardiovascular disease. It has been postulated that inflammatory mediators prevalent in periodontal disease may impact on atheroma formation and the thrombotic process. In cross-sectional, observational studies, periodontitis is associated with elevated C-reactive protein (CRP), hyperfibrinogenaemia and moderate leukocytosis. CRP levels have also been shown to decrease following periodontal therapy. CRP is a reliable marker of the acute phase reaction to infections and/or inflammation and is a powerful predictor of future coronary events.

Tutor perceptions of the use of a reflective portfolio within a pastoral tutor system to facilitate undergraduate personal development planning

All Higher Education Institutions in the UK are now required to provide transcripts of student activity and outcomes of summative assessments. In addition, the student should be able to reflect on their learning and plan their own development. This article reports on the staff evaluation of the use of a reflective portfolio facilitating the production of highly individualised personal development plans within an existing tutor system. A number of significant issues are highlighted; tutor systems adopting this approach must maintain flexibility for managing student crises when they arise, the difference between appraisal and assessment needs clear definition for both students and tutors, training in basic mentoring skills should be provided for all tutors, tutors should be aware of the difficulties many students experience with reflection and also be alert to the over reflective learner.

The effect of cyclosporin on cell division and apoptosis in human oral keratinocytes

BACKGROUND AND OBJECTIVE

Gingival overgrowth (GO) is a side-effect of cyclosporin A (CsA) therapy and is characterised by enlargement of the gingiva with epithelial thickening and overproduction of extracellular matrix components. The pathogenesis of the epithelial thickening in GO remains obscure. The objective of the present study was to investigate the effects of CsA on the growth of oral epithelial cells in vitro and to test the hypothesis that CsA influences apoptosis in these cells.

MATERIAL AND METHODS

Cyclosporin was cocultured with an immortalized normal human oral keratinocyte cell line (HOK-16B), an epitheloid cervical carcinoma cell line (HeLa) and primary oral keratinocytes. Cell division was quantified using a CyQUANT kit. Apoptosis was induced using tumour necrosis factor-alpha (TNF-alpha) and assayed by analysis of caspase-3 activity. Expression of the anti-apoptotic protein, Bcl-2, was measured by western blotting.

RESULTS

CsA exhibited a dose- and time-dependent inhibition of cell division in all three keratinocyte cell cultures. Significantly, HOK-16B cells treated with high doses of CsA (10 alphag/ml) did not recover their proliferative capacity 3 d after withdrawal of CsA, indicating that CsA-induced inhibition of growth is not temporary. Concentrations of CsA that inhibited cell division (1 microg/ml) did not have any effect on constitutive or TNF-alpha -induced apoptosis or Bcl-2 expression in HOK-16B cells.

CONCLUSION

CsA inhibits oral epithelial cell division and this effect is not associated with changes in apoptosis in these cells. The action of CsA on oral epithelial cells may be associated with a long-lasting stress signal, which might account for some of the pathological effects of this drug.

The management of drug-induced gingival overgrowth

OBJECTIVES

This review critically evaluates the different therapies that are available to manage drug-induced overgrowth (DIGO).

MATERIAL AND METHODS

This review is based on literature identified using the online databases MEDLINE and PUB MED. It is not a systematic review, but a conventional review of the relevant literature.

RESULTS

Patients benefit from a non-surgical approach if this can be delivered before commencement of medication although in many instances this may not be practicable. Systemic antibiotic usage has been evaluated in the management of ciclosporin-induced gingival overgrowth. Efficacy appears to be equivocal and long-term use is undesirable. Surgical excision remains the main treatment option especially for patients with severe overgrowth. Few studies have compared different techniques with respect to recurrence rate or post-operative sequelae.

CONCLUSION

DIGO is a common clinical problem that often requires intervention. Non-surgical techniques can limit the occurrence of this unwanted affect, reduce the extent of plaque-induced gingival inflammation and reduce the rate of recurrence. Wherever possible this management strategy should be adopted first. Surgical treatment is often the most reliable option and scalpel gingivectomy remains the treatment of choice. Further investigations are required to develop appropriate management strategies to prevent recurrence of DIGO.

A randomized controlled trial of implant-retained mandibular overdentures

Evidence from randomized clinical trials of implant-retained overdentures is very limited at the present time. The aim of this study was to compare implant-retained mandibular overdentures and conventional complete dentures in a randomized controlled trial (RCT). Our a priori hypothesis was that implant-retained mandibular overdentures would be significantly better than conventional complete dentures. Edentulous patients (n = 118) were randomly allocated to either an Implant Group (n = 62) or a Denture Group (n = 56). Patients completed the Oral Health Impact Profile (OHIP) and a denture satisfaction scale pre-treatment and three months post-treatment. Upon completion of treatment, both groups reported improvement (p < 0.001, Wilcoxon Ranks Sum test) in oral-health-related quality of life and denture satisfaction. There were no significant post-treatment differences between the groups, but a treatment effect may be masked by application of "intention to treat" analysis. The OHIP change scores were significantly greater for patients receiving implants than for those who refused them.

The efficacy of three different surgical techniques in the management of drug-induced gingival overgrowth

OBJECTIVES

The aim of the present study was to evaluate the efficacy of three different surgical techniques in both the management and effect upon rate of overgrowth recurrence of drug-induced gingival overgrowth (DIGO).

MATERIALS AND METHODS

Two cohorts of patients who required surgical correction of their DIGO participated in the study. After baseline periodontal measures (plaque index, gingival inflammation and probing pocket depths), the patients underwent surgery. A split-mouth, crossover design was used to compare conventional gingivectomy with flap surgery (n=27), and conventional gingivectomy with laser excision (n=23). The main outcome variable was the rate of recurrence of DIGO following surgery.

RESULTS

At 6 months, there was significantly less recurrence (p=0.05) in patients treated with laser excision, compared with those treated by conventional gingivectomy. The differences in rate of recurrence of DIGO were also reflected in changes in several periodontal parameters. Flap surgery offered no advantage over conventional gingivectomy with respect to the rate of recurrence.

CONCLUSIONS

DIGO can be managed by a variety of techniques. Laser excision results in a reduced rate of recurrence.

The dental attitudes, knowledge and health practices of patients with Juvenile Idiopathic Arthritis

AIM

To investigate the dental attitudes, knowledge and dental health practices of children and adults with a previous diagnosis of Juvenile Idiopathic Arthritis (JIA).

STUDY DESIGN

A self-completion questionnaire.

METHODS

Ninety-one children and 82 adults with JIA were age and gender matched with 152 healthy controls. For those below the age of 16 years, the parents' attitude, knowledge and dental health practices were investigated by the questionnaire. The adult subjects and controls completed an identical questionnaire assessing their own attitude, knowledge and dental health practices.

RESULTS

Response rates of 84% and 75% were achieved for the subject and controls respectively. Both groups responded similarly to questions assessing perception of different medical conditions. The majority of respondents thought leukaemia was a very serious condition. Twenty-seven percent of subjects and 34% of controls felt dental decay was "slightly or not serious". Ninety percent of subjects and 93% of controls knew having sweet snacks during the day would harm teeth, but fewer were sure that eating sweet foods at mealtimes only would help reduce decay. The majority of respondents (63% and 56% respectively) did not know whether children should receive fluoride tablets but the majority of subjects in both groups had attended a dentist within the last year.

STATISTICS

Descriptive analyses and chi-squared analysis were undertaken. A p-value of < or =0.01 was taken as strong evidence of a difference between groups.

CONCLUSION

The perception of health and illness by both groups was appropriate. The questions investigating dental knowledge revealed understanding of the basic messages of prevention of dental disease, but finer detail appeared less well understood. Responses concerning dental health confirmed positive attitudes towards good dental health habits. The benefits of brushing with fluoride toothpaste were known, and the majority toothbrushed daily and received dental care within the previous year.

Analysis of changes in gingival contour from three-dimensional co-ordinate data in subjects with drug-induced gingival overgrowth

OBJECTIVES

This aim of this study was to develop and assess a technique that could be used to assess accurately the gingival volume changes seen in drug-induced gingival overgrowth by the analysis of data obtained from an entire gingival surface by means of three-dimensional imaging.

MATERIAL AND METHODS

Stone dental models of patients before and after gingivectomy procedures were digitized with a laser scanner and then regenerated as computer models constructed from the acquired three-dimensional co-ordinate data. A comparison of superposed "before" and "after" surfaces was undertaken to assess and accurately quantify changes in gingival contour.

RESULTS

The mean vertical tissue reduction varied from 1.58 to 2.56 mm in the four study subjects and individual differences are shown. The maximum thickness of removed buccal gingival overgrowth was found to range between 1.20 and 3.40 mm. The volume of tissue removed from each inter-dental papilla ranged from 4.2 to 46.1 mm3 and the mean volume of the papilla removed from each subject+/-SD values was 24.8+/-13.1 mm3.

CONCLUSION

This method will measure changes in gingival tissues to within 60 microm in one plane, making it ideal for the assessment of longitudinal changes in gingival contour as seen in the development of gingival overgrowth, its recurrence after surgery or the changes in volume brought about by surgery.

A quantitative study of enamel acid etch patterns on surfaces used for retention of resin-bonded fixed prostheses

This study investigated the quality of in vivo etch patterns on the bonding surfaces of 46 abutment teeth following acid etching with 37% phosphoric acid for 30 seconds. Two-stage putty and light bodied addition cured silicone impressions of the etched lingual surfaces were used to form replicas that were then viewed using the scanning electron microscope. Over 69% of the lingual bonding surface area of incisors, canine and premolars were unetched, 16% barely etched, 7% etched and less than 2% ideally etched. There was no significant difference in the quality of etch between different tooth types. There was a significantly greater proportion of poorly etched enamel towards the cervical margin in comparison with the occlusal half. This may have implications in retention of resin bonded bridges.

Lasers in periodontology

Since the development of the ruby laser by Maiman in 1960, lasers have been widely employed in medicine for a number of years. The purpose of this paper is to summarize potential applications for lasers in dentistry, with special regard to periodontology. This article briefly describes clinical applications of lasers and laser safety. Particularly, the use of a diode laser seems to be promising, especially in already compromised transplant patients, who need to be treated with a technique where the operative and post-operative blood loss, post-operative discomfort and the recurrence of drug-induced gingival overgrowth need to be kept to a minimum or eliminated. Therefore, the use of lasers in periodontology may lead to an alteration in present clinical practice and help to establish the best management strategy because, by maintaining periodontal health, the life quality of patients can be improved.

Plasma TGF-beta1 as a risk factor for gingival overgrowth

BACKGROUND AND AIMS

Induction of the pro-fibrotic growth factor TGF-beta1 has been suggested as a possible mechanism through which immunosuppressant drugs may induce gingival overgrowth. This study aims to investigate plasma levels of TGF-beta1 and relate them to the development and severity of gingival overgrowth in immunosuppressed transplant patients.

MATERIALS AND METHODS

One hundred and thirty-two ciclosporin-treated and 13 tacrolimus-treated transplant patients and 24 drug-free control subjects underwent a full periodontal examination including a determination of the presence and severity of gingival overgrowth.

RESULTS

Plasma TGF-beta1 concentrations were determined by ELISA, and were found to be significantly elevated in samples from the transplant patients (mean=29.1 ng/ml) as compared with controls (mean=6.1 ng/ml, p<0.0001). There was no significant difference between the levels of plasma TGF-beta1 in the ciclosporin- and tacrolimus-treated patient groups.

CONCLUSIONS

Furthermore, concomitant treatment with calcium channel blockers did not influence the levels of plasma TGF-beta1 in the patients group. The relationship between gingival overgrowth, independent periodontal variables and TGF-beta1 plasma concentrations was examined using univariate and multivariate regression analyses; low TGF-beta1 plasma concentrations were found to be a risk factor for gingival overgrowth in immunosuppressed patients concomitantly receiving a calcium channel blocker.

Post-transplant lymphoproliferative disorders presenting as gingival overgrowth in patients immunosuppressed with ciclosporin. A report of two cases

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) can occur in patients maintained on immunosuppressive therapy following transplantation. This paper describes two cases of PTLD occurring in gingival tissues, in patients receiving ciclosporin following cardiac transplantation.

TREATMENT

The lesions were localised to gingival tissues, mimicking ciclosporin-induced gingival overgrowth. They were removed surgically and the ciclosporin dose reduced to help prevent recurrence.

CONCLUSION

The importance of histopathological examination of all tissue removed during routine gingivectomy procedures for ciclosporin-induced gingival overgrowth is highlighted.

Oral mucosal and osseous disorders in frail elders*

OBJECTIVE

This paper reviews the implications of frailty for oral health in old age due to the incidence of oral pathoses following on mucosal atrophy, tooth loss, trauma from dentures, polypharmacy, malnutrition, salivary disorders, degeneration of jawbone and cancer.

BACKGROUND

Frailty as a condition of old age occurs when elders have energy levels below a critical threshold, or when the social or cultural environment is limited.

RESULTS

Frail elders are particularly vulnerable to pathoses, but not simply because of old age per se. Oral diseases accompanying frailty are due to a complicated mixture of biopsychosocial changes that accompany old age.

CONCLUSIONS

Management of oral mucosal and osseous disorders in frail elders requires an understanding of the changes that occur with advancing age.

Salivary proteins and cytokines in drug-induced gingival overgrowth

Little is known about the involvement of saliva in gingival overgrowth (GO). It was hypothesized that, in this situation, the composition of saliva is altered. Thus, proteins, albumin, cytokines, and growth factors in whole and glandular saliva were investigated. Differences between glandular and gingival contributions to the composition of saliva were explored in patients medicated with cyclosporin who exhibited GO (responders), those without GO (non-responders), and non-medicated subjects (controls). In whole saliva, interleukin-1alpha (IL-1alpha), IL-6, IL-8, epidermal growth factor (EGF), nerve growth factor (NGF), and albumin were detected, but in glandular saliva only EGF and NGF were identified. Albumin and IL-6 differed significantly between responders and controls, although the overall profile of salivary proteins remained unchanged. Thus, inflammatory cytokines and albumin are confined to whole saliva and are associated with GO, whereas its content of EGF and NGF appears unaffected by cyclosporin.

Prevalence of gingival overgrowth in transplant patients immunosuppressed with tacrolimus

AIMS

The study aims to determine the prevalence and severity of gingival overgrowth in a group of adult organ transplant recipients immunosuppressed with tacrolimus in comparison with ciclosporin, and to examine various risk factors for the development of gingival overgrowth.

METHODS

Forty patients taking tacrolimus were compared with 197 ciclosporin patients. Demographic, pharmacological and periodontal data were recorded for all patients. Comparison between the groups was made using independent sample t-tests, chi2 statistic or Mann-Whitney test. The effects of risk variables on overgrowth severity were examined using forward and backward stepwise regression analysis.

RESULTS

Those taking tacrolimus had a significantly lower mean gingival overgrowth score (14.1%) compared with ciclosporin (22.4%). Fifteen percent of the tacrolimus group had clinically significant gingival overgrowth compared with 30% in the ciclosporin group (p=0.053).

CONCLUSIONS

The prevalence and severity of gingival overgrowth is less in adult transplant patients taking tacrolimus compared with ciclosporin. Concomitant use of calcium channel blockers and previous medication with ciclosporin are significant risk factors for the presence and severity of gingival overgrowth. Patients who have alteration of their immunosuppressant from ciclosporin to tacrolimus may persist in demonstrating gingival overgrowth attributable to their ongoing therapy with calcium channel blockers.

Increased prevalence of dental caries and poor oral hygiene in juvenile idiopathic arthritis

OBJECTIVES

Recent decades have seen a trend to treat juvenile idiopathic arthritis (JIA) with increasing immunosuppression to improve the long-term outcome. Poor oral hygiene and dental decay cause significant morbidity, and patients with chronic disease (who may be further immunocompromised by treatment) are at greater risk. This study investigated patients with JIA using standard measures of oral health.

METHODS

One hundred and forty-nine patients with JIA were included. The children were attending a regional paediatric rheumatology service and the adults were attending an adult rheumatology clinic. Random age- and sex-matched healthy controls were recruited from a dental teaching hospital. The structured dental examination included standard epidemiological indices of oral hygiene (gingival index, plaque index, oral cleanliness index) and dental decay [DMFT (decayed, missing or filled teeth) index].

RESULTS

JIA patients, at all ages, had increased levels of dental decay and poor oral hygiene. This increased level of decay was statistically significant in the patients aged 0-11 yr. Significant levels of untreated caries and increased levels of missing teeth were found in JIA, suggesting that patients with JIA had less restorative dental treatment, with tooth extraction often the chosen option for the treatment of dental decay.

CONCLUSIONS

This is the largest study of oral health in JIA and is cross-sectional with non-diseased controls. It shows significantly increased levels of poor oral hygiene and dental decay in patients with JIA. The high levels of untreated dental decay suggest barriers to dental care. These results emphasize the role of regular dental care in the multidisciplinary management of JIA.

Cardiovascular diseases and periodontology

BACKGROUND

Cardiovascular diseases represent a widespread heterogeneous group of conditions that have significant morbidity and mortality. The various diseases and their treatments can have an impact upon the periodontium and the delivery of periodontal care.

AIM

In this paper we consider three main topics and explore their relationship to the periodontist and the provision of periodontal treatment.

METHOD

The areas reviewed include the effect of cardiovascular drugs on the periodontium and management of patients with periodontal diseases; the risk of infective endocarditis arising from periodontal procedures; the inter-relationship between periodontal disease and coronary artery disease.

RESULTS AND CONCLUSIONS

Calcium-channel blockers and beta-adrenoceptor blockers cause gingival overgrowth and tooth demineralisation, respectively. Evidence suggests that stopping anticoagulant therapy prior to periodontal procedures is putting patients at a greater risk of thromboembolic disorders compared to the risk of prolonged bleeding. The relationship between dentistry and infective endocarditis remains a controversial issue. It would appear that spontaneous bacteraemia arising from a patient's oral hygiene practices is more likely to be the cause of endocarditis than one-off periodontal procedures. The efficacy of antibiotic prophylaxis is uncertain (and unlikely to be proven), and the risk of death from penicillin appears to be greater than the risk of death arising from infective endocarditis. Finally, the association between periodontal disease and coronary artery disease has been explored and there seem to be many issues with respect to data handling interpretation. Many putative mechanisms have been suggested; however, these only further highlight the need for intervention studies.