A personalized avatar-based web application to help people understand how social distancing can reduce the spread of COVID-19: a cross-sectional observational pre-post study

BACKGROUND

To reduce the transmission of SARS-CoV-2 and the associated spread of COVID-19, many jurisdictions around the world imposed mandatory or recommended social or physical distancing. As a result, at the beginning of the pandemic, various communication materials appeared online to promote distancing. Explanations of the science underlying these mandates or recommendations were either highly technical or highly simplified.

OBJECTIVE

This study aimed to understand the effects of a dynamic visualization on distancing. Our overall aim was to help people understand the dynamics of the spread of COVID-19 in their community and the implications of their own behavior for themselves, those around them, the healthcare system, and society.

METHODS

We used Scrum, an agile framework, JavaScript (Vue.js framework), and code already developed for risk communication in another context of infectious disease transmission, we rapidly developed a new personalized web application. In our application, people make avatars that represent themselves and the people around them. These avatars are integrated into a 3-minute animation illustrating an epidemiological model for COVID-19 transmission, showing the differences in transmission with and without distancing. During the animation, the narration explains the science of how distancing reduces transmission of COVID-19 in plain language in English or French. The application offers full captions to complement the narration and a descriptive transcript for people using screen readers. We used Google Analytics to collect standard usage statistics. A brief, anonymous, optional survey also collected self-reported distancing behaviors and intentions in the previous and coming weeks, respectively. We launched and disseminated the application on Twitter and Facebook on April 8-9, 2020.

RESULTS

After 26 days, the application received >3600 unique hits from 82 countries. The optional survey at the end of the application collected 182 responses. Among this small subsample of users, survey respondents were nearly all (96.0%) already practicing distancing and (97.2%) indicated that they intended to practice distancing in the coming week. Among the small minority of people (n=7) who indicated that they had not been previously practicing distancing, 2 (29%) reported that they would practice distancing in the week to come.

CONCLUSIONS

We developed a web application to help people understand the relationship between individual-level behavior and population-level effects in the context of an infectious disease spread. This study also demonstrates how agile development can be used to quickly create personalized risk messages for public health issues like a pandemic. The non-randomized design of this rapid study prevents us from concluding the application's effectiveness; however, results thus far suggest that avatar-based visualizations may help people understand their role in infectious disease transmission.

CLINICALTRIAL

Combined use of two supervised learning algorithms to model sea turtle behaviours from tri-axial acceleration data

Accelerometers are becoming ever more important sensors in animal-attached technology, providing data that allow determination of body posture and movement and thereby helping to elucidate behaviour in animals that are difficult to observe. We sought to validate the identification of sea turtle behaviours from accelerometer signals by deploying tags on the carapace of a juvenile loggerhead (Caretta caretta), an adult hawksbill (Eretmochelys imbricata) and an adult green turtle (Chelonia mydas) at Aquarium La Rochelle, France. We recorded tri-axial acceleration at 50 Hz for each species for a full day while two fixed cameras recorded their behaviours. We identified behaviours from the acceleration data using two different supervised learning algorithms, Random Forest and Classification And Regression Tree (CART), treating the data from the adult animals as separate from the juvenile data. We achieved a global accuracy of 81.30% for the adult hawksbill and green turtle CART model and 71.63% for the juvenile loggerhead, identifying 10 and 12 different behaviours, respectively. Equivalent figures were 86.96% for the adult hawksbill and green turtle Random Forest model and 79.49% for the juvenile loggerhead, for the same behaviours. The use of Random Forest combined with CART algorithms allowed us to understand the decision rules implicated in behaviour discrimination, and thus remove or group together some 'confused' or under--represented behaviours in order to get the most accurate models. This study is the first to validate accelerometer data to identify turtle behaviours and the approach can now be tested on other captive sea turtle species.

Incidence, risk factors and clinical consequences of neutropenia following kidney transplantation: a retrospective study

Neutropenic episodes in kidney transplant patients are poorly characterized. In this retrospective study, neutropenia was experienced by 112/395 patients (28%) during the first year posttransplant. The only factor found to be significantly associated with the occurrence of neutropenia was combined tacrolimus-mycophenolate therapy (p < 0.001). Neutropenic patients experienced more bacterial infections (43% vs. 32%, p = 0.04). Grade of neutropenia correlated with the global risk of infection. Discontinuation of mycophenolic acid (MPA) due to neutropenia was associated with an increased incidence of acute rejection (odds ratios per day 1.11, 95% confidence intervals 1.02-1.22) but not with reduced renal function at 1 year. The time from onset of neutropenia to MPA discontinuation correlated with the duration of neutropenia. Granulocyte colony-stimulating factor (G-CSF) administration was safe and effective in severely neutropenic kidney graft recipients, with absolute neutrophil count >1000/microL achieved in a mean of 1.5+/-0.5 days. Neutropenia is an important and frequent laboratory finding that may exert a significant influence on outcomes in kidney transplantation. As well as leading to an increased incidence of infection, it is associated with a higher rate of allograft rejection if MPA is discontinued for >6 days (p = 0.02). G-CSF accelerates recovery of neutropenia and may be a good therapeutic alternative for severely neutropenic patients.

Création et validation d’un autoquestionnaire mesurant la qualité de vie de patients souffrant de schizophrénie : l’échelle schizophrenia quality of life (SOL)

RATIONALE/OBJECTIVE: Quality of Life (QOL) has been recognized as an important measure of the outcome of patients by clinicians and policy makers in Mental Health. The emerging consensus in the health field that personal values and the patient's preferences are important in monitoring the quality of medical care outcomes makes it even more important to assess the patient's perspectives. Unfortunately, there is little consensus about what constitutes QOL or how to measure it, particularly in psychotic patients. The objective of this study is to report the stages of development and validation of a QOL questionnaire based on issues pertinent to patients with schizophrenia.

METHOD

During a first phase, identical pattern were identified among interviews (conducted by psychologists) of schizophrenic patients (DSM IV, n = 100), mental health staff (n = 20) and families (n = 20). The data gathered in the first phase were discussed and organized, by 25 experts, into a structure that made up the skeleton of the scale (133 items, 17 factors). Based on a prospective epidemiological study conducted with 337 French psychiatrists, a validation analysis of structural and psychometric proprieties was performed. Finally reliability of the scale was assessed by a second test/retest (D0, D7) study (n = 100).

RESULTS

A total of 686 schizophrenic, schizophreniform or schizoaffective patients (DSM IV) were included. Internal consistency analysis identified 14 factors (74 items), all with a Cronbach's alpha of at least 0.75: professional life (0.95), affective and sexual life (0.92), illness knowledge (0.90), relationship (0.92), life satisfaction, (0.87), coping with drugs (0.79), drugs impact on the body (0.87), daily life (0.83), family relationship (0.81), future (0.88), security feeling (0.84), leisure (0.87), money management (0.76) and autonomy (0.75). Construct validity was confirmed (Pearson test) using established clinical (Brief Psychiatry Rating Scale and Clinical Global Improvement), social (Psychological Aptitude Rating Scale) and generic quality of life (Functional Status questionnaire) measures, correlation coefficient was significant for all factors but 2 in the BPRS (illness knowledge and coping with drugs) and 3 in the CGI (illness knowledge, coping with drugs and life satisfaction). Lastly, test/retest indicated high reliability for each factor (p < 0.001), the lower correlation coefficient (r) was 0.526.

CONCLUSIONS

The Schizophrenia Quality Of Life-scale (SOL), based on a patient's point of view approach, is an efficient, multidimensional instrument designed for the measurement of the consequences of schizophrenia on individuals' lives.

Locally delivered antimicrobials for the treatment of chronic periodontitis

The basic treatment of chronic periodontitis is a mechanical debridement of periodontal pockets by scaling and root planing (S/RP) in combination with efficient plaque control. Locally delivered antiseptics (LDA) have been proposed to practitioners and, while subgingival irrigation of antiseptics is still used in clinical practice, the introduction in our therapy of a slow release and sub-gingival delivery of tetracycline has changed the rationale from a mechanical treatment towards a combined therapy for full mouth/sites disinfection. Various antibiotics, antiseptics and resorbable carriers are now proposed with similar targets to arrest disease progression. In chronic periodontitis, LDA cannot be used routinely in combination with S/RP, because of the limited clinical benefit, even if an increased percentage of deep sites may show an improvement. Prospective multicenter studies considering risk factors for disease progression have to be designed to identify patients who may benefit the most from LDA. For non-responding sites or recurrent pockets, the controversies are limited, because a combined S/RP and LDA may avoid the need for surgery. However, the patient cost/benefit ratio needs to be estimated as well as adverse effects in particular antibiotics.

Osseotite implant: 3-year prospective multicenter evaluation

PURPOSE

This prospective multicenter study evaluates the cumulative success rate of the Osseotite implant after 3 years of prosthetic loading.

MATERIALS AND METHODS

A total of 413 Osseotite implants (Implant Innovations) were placed in 142 patients (completely or partially edentulous) in five dental offices exclusively devoted to implants. The average age of the patients was 58.3 years. Of the 413 implants, 191 were placed in the maxilla and 222 in the mandible; 271 (65.6%) were posterior implants and 142 (34.4%) were anterior implants. Clinical and radiographic evaluations were made after completion of the prosthetic restoration, after 6 months of loading, at 1 year, and at 3 years.

RESULTS

A cumulative success rate of 95.3% was obtained after 3 years of prosthetic loading. The success rate was similar in both arches: 95.1% in the maxilla and 96.8% in the mandible. Early failures (before prosthetic loading) were greater (n = 12) than late failures (n = 2). After 3 years of prosthetic loading, the marginal bone level of 385 (93.2%) implants were evaluated radiographically. Bone level was at the first thread for 91.4% of the implants. A slightly increased loss was observed around 26 implants (6.7%). Including survival implants, the cumulative implant success rate after 3 years was 96%. A success rate of 98.4% was obtained with 187 short implants (8, 5 and 10 mm) reported in this multicenter evaluation.

CONCLUSION

This multicenter evaluation demonstrates excellent predictability for Osseotite implants.

Wide-diameter implants: new concepts

At the end of the 1980s, it was suggested that wide-diameter implants be used to better the prognosis in cases in which the condition of the supporting bone is unfavorable. Technical improvements associated with different shapes and materials used for implants have led to an evolution of our concepts of surgical and prosthetic treatments. The aim of these new suggestions is to optimize the functional and esthetic result while respecting the fundamental principles of osseointegration. Up to the present time, very few studies have been published on wide-diameter implants. However, the short- and medium-term results that have been reported have been very satisfactory.

Root coverage and papilla reconstruction using autogenous osseous and connective tissue grafts

Previous studies have reported that the distance from the interdental crest of bone to the apical portion of the contact of the two approximating teeth must be 5 mm or less to support a stable interdental papilla. The reconstruction of a stable, long-term papilla for esthetic purposes must therefore consider interdental bone reconstruction. Autogenous osseous graft material was harvested from the tuberosity and augmented with a subperiosteal connective tissue graft for papilla reconstruction between the maxillary central incisors. Flap design, osseous graft fixation with a screw, connective tissue placement, wound closure, and suturing techniques are presented. To enhance the final result, porcelain veneers were bonded to the approximating central incisors. This case report demonstrates a surgical procedure that has not been reported to date for papilla reconstruction to enhance periodontal esthetics.

The self-tapping and ICE 3i implants: a prospective 3-year multicenter evaluation

This multicenter prospective clinical evaluation was undertaken to determine the therapeutic success and marginal bone level stability of 3i's self-tapping and ICE implants after 3 years of prosthetic loading. Between July 1995 and June 1996, 189 completely or partially edentulous patients were treated with 614 machined-surface screw-type commercially pure titanium implants (self-tapping or ICE). Two hundred seventy-seven self-tapping implants were placed in 85 patients (average age of 56 years), and 337 ICE implants were placed in 104 patients (average age of 61 years). A total of 360 implants (58.6%) were placed in posterior segments. Easier placement was reported with the ICE implant in normal or dense bone. For the self-tapping implants, survival rates of 92.9% and 91.6% were noted after 1 and 3 years of prosthetic loading, respectively. Survival rates of 95.4% and 93.8% were obtained with the ICE implant for the same periods. Late failures (after loading) were more common than early failures (before loading) for both types of implants. The marginal bone level of 238 self-tapping implants (85.9%) and of 307 ICE implants (91%) was radiographically evaluated at 3 years. Marginal bone level was at the first thread for 95.1% of implants. A loss of marginal bone level of 2 to 4 threads was noted for 4.9% of the evaluated implants. No implant showed bone loss greater than the fourth thread. Overall survival rates of 94.3% and 92.9% were obtained after 1 and 3 years of prosthetic loading, respectively, for 596 and 588 implants.

Development of vitrified matured cattle oocytes after thawing and culture in vitro

Bovine oocytes were partly denuded either at the beginning (t0) or six hours (t6) after the beginning of maturation and vitrified by the open pulled straw method at the end of the maturation process. After warming and fertilisation, their development in vitro and in vivo was assessed. The rates of production of blastocysts achieved in vitro were 3.4 per cent for the t0 group and 0.9 per cent for the t6 group compared with 40.4 per cent for the control oocytes. After transfer at the blastocyst stage pregnancies have been established in the three groups. Some of these pregnancies originated from vitrified oocytes which were further vitrified at the blastocyst stage before being transferred into synchronised recipients.

Role of aberrant nitric oxide synthase-3 expression in cerebrovascular degeneration and vascular-mediated injury in Alzheimer's disease

Nitric oxide (NO) is an important signaling molecule that is generated through the catalytic activity of nitric oxide synthase (NOS). In the brain, NO mediates neuronal survival, synaptic plasticity, vascular smooth muscle relaxation, and endothelial cell permeability. Previous studies demonstrated aberrant expression of the NOS-III gene in neurons and glial cells in brains with Alzheimer's disease (AD). Since NOS-III is also expressed in vascular cells, and cerebrovascular disease (CVD) frequently complicates the pathology of AD, we investigated the role of NOS-III in relation to CVD in AD. Vasculopathy in AD + CVD was characterized by thickening and hyalinization of the media of small and medium-size vessels, variable degrees of beta-amyloid (A beta) deposition, and increased apoptosis of vascular smooth muscle and endothelial cells, particularly involving white matter vessels. These abnormalities were correlated with reduced levels of NOS-III expression in cerebral vessels. Double-labeling studies demonstrated that the low levels of cerebrovascular NOS-III were associated with increased levels of the pro-apoptosis gene product, p53 in smooth muscle and endothelial cells, suggesting a role for altered NOS-III expression in AD-associated vascular degeneration. Constitutively reduced cerebrovascular NOS-III expression and NO production could also lead to cerebral hypoperfusion due to impaired vasodilation responses, and diminished capacity to remove respiratory waste products and toxins from the extracellular space due to reduced capillary permeability. The role for phosphodiesterases as modulators of NOS activity is discussed, as these molecules represent potential therapeutic targets given their cell type and cyclic nucleotide specificities of action.

Aberrant expression of nitric oxide synthase III in Alzheimer's disease: relevance to cerebral vasculopathy and neurodegeneration

Alzheimer's disease (AD) has heterogeneous pathology, in part due to the large subset of cases (AD+CVD) with superimposed vascular lesions that are sufficient in number and distribution to accelerate the clinical course of dementia. Brains with AD+CVD have lower densities of neurofibrillary tangles and A beta-amyloid diffuse plaques, and increased numbers of cerebral vessels exhibiting p53-associated apoptosis relative to brains with uncomplicated AD. AD and AD+CVD both exhibit altered expression of the nitric oxide synthase 3 (NOS-III) gene; however, in AD+CVD, reduced NOS-III expression in cerebral vessels is associated with an increased frequency of vascular lesions, vascular smooth muscle cell apoptosis, and A beta-amyloid plaques. In contrast, experimental and spontaneous focal acute and subacute cerebral infarcts are associated with increased NOS-III expression in perifocal neurons, glial cells, cerebrovascular smooth muscle and endothelial cells, and diffuse A beta-amyloid plaque formation. This suggests that ischemic injury and oxidative stress can precipitate NOS-III-mediated cell loss and neurodegeneration. A role for aging-associated impaired mitochondrial function as a contributing factor in AD and CVD is suggested by the reduced levels of mitochondrial protein observed in AD and AD+CVD cortical neurons and vascular smooth muscle and endothelial cells. The aggregate findings suggest that cell loss and neurodegeneration may be mediated by somewhat distinct but overlapping mechanisms in AD and AD+CVD.

Embryo production by ovum pick up in unstimulated calves before and after puberty

The possibility of producing embryos from oocytes repeatedly collected from unstimulated calves was tested, and results obtained before and after puberty were compared in the same animals. Ovum pick-up (OPU) coupled with in vitro embryo production was used on 2 sets of 7 and 9 calves, aged 7 to 10 m.o. at the start of the experiment. The oocytes were collected twice a week during a 2-m.o. period before puberty and a 1-m.o. period after puberty. Oocytes were fertilized and co-cultured with cumulus cells in modified synthetic oviduct fluid (SOF) up to Day 7 post insemination. Some Day 7 blastocysts were vitrified and transferred to recipient heifers. An average of 3.8 to 6.8 follicles was punctured per OPU session; 1.9 to 3.1 oocytes were collected, of which more than 60% were of good quality. The number of punctured follicles and collected oocytes varied between donors. Blastocyst rates of 19 to 27% were obtained for the 2 sets. Three normal calves were born from the transfer of 20 vitrified embryos. While no significant difference was observed for the first set of calves, a significant decrease in the number of punctured follicles was observed after puberty in the second set. A direct correlation was also obtained between the number of follicles punctured before and after puberty in the same animal. In conclusion, oocytes can be collected by repeated OPU in calves 7 to 10 m.o. old without affecting their growth or the onset of puberty. An average of 5 to 11 (range 0 to 16) blastocysts per donor was produced over 2 month. However, important variations were found between donors. The correlation observed for the number of follicles punctured before and after puberty suggests that this parameter is determined before puberty.

Root coverage and papilla reconstruction in Class IV recession: a case report

While root coverage is predictable for Miller Class I and II recessions, the surgical regeneration or reconstruction of a lost interdental papilla is more difficult to obtain. To date only a few successful case reports have been reported, and there are no studies that report a predictable technique to obtain papilla reconstruction or root coverage on Class IV recessions. This case report, which is part of a preliminary study, outlines a surgical technique to obtain simultaneous root coverage and papilla reconstruction.

Restorative and periodontal considerations of short clinical crowns

The purpose of this review was to examine the periodontal and restorative factors related to restoring teeth with short clinical crowns. Modes of therapy are usually combined to meet the biologic, restorative, and esthetic requirements imposed by short clinical crowns. The complications presented by teeth with short clinical crowns demand a comprehensive treatment plan and proper sequencing of therapy to ensure a satisfactory result. Visualization of the desired result is a prerequisite of successful therapy. Short clinical crowns present many problems to the restorative dentist. Restorations should have proper form, function, and esthetics while promoting the maintenance of tissue health in the surrounding areas. However, adequate tooth structure for achieving these goals may not always be available. While it is difficult to precisely define minimum crown length, this study offers guidelines for defining a short clinical crown and suggests procedures for achieving a predictable result without compromising the periodontium. The consequences of placing a restoration on a tooth with insufficient crown length are discussed and various treatment methods are reviewed.

Surgical reconstruction of the interdental papilla

The traditional goal of disease elimination in the anterior region opens the interproximal spaces, causing flattening or cratering of the interdental papilla. Today's patients increasingly demand esthetic results in addition to periodontal treatment, and recent advances in periodontal plastic surgery have enhanced the periodontist's ability to address these concerns. Three case reports demonstrate a proposed surgical technique for the reconstruction of collapsed interdental papillae using a connective tissue graft under the buccal and palatal flaps.

Clinical evaluation of a bioabsorbable regenerative material in mandibular class II furcation therapy

30 periodontally compromised adult subjects with mandibular buccal class II furcation defects were recruited for this study. All selected defects were treated according to the biological principles of guided tissue regeneration. The subjects were randomly assigned to 2 parallel groups. The test group (n=15) received a bioabsorbable polyglycolic-polylactic membrane (PGA/PLA group); the control group (n=15) received a non-resorbable expanded polytetrafluoroethylene membrane (ePTFE group). After initial therapy, baseline measurements were recorded including plaque index, gingival index, vertical and horizontal probing depths, clinical attachment level and depth of the recession. Recall visits were made at 1, 2, 4, 6, 8, 12, and 24 weeks. At 12 months, all baseline clinical parameters were again measured. The data analysis did not demonstrate a significant difference between the 2 groups. The vertical probing depth and attachment level changes were statistically significant in each group. The postoperative recession was 0.6 mm in the ePTFE group (p<0.05) and 0.8 mm (p<0.05) in the PGA/PLA group. Compared to the initial measurements, the mean changes in horizontal probing depth were 2.7 mm and 2.5 mm (p<0.001), corresponding to mean reductions of 41.5% and 40.9% for the ePTFE and the PGA/PLA groups respectively. The results of this study suggest that 12 months after initial surgery, similar clinical improvements can be obtained in GTR therapy of buccal class II furcation lesions, regardless of whether bioabsorbable PGA/PLA membranes or non-resorbable ePTFE membranes are used.

Clinical evaluation of tetracycline HCl conditioning in the treatment of gingival recessions. A comparative study

Thirty Class I and Class II recessions in 30 patients were treated with a modified subepithelial connective tissue graft procedure. Fifteen recessions in the test group received a tetracycline hydrochloride (50 mg/ml) root treatment for 5 minutes (TTC-HCl group); the remaining 15 recessions composed the control group and received a citric acid root treatment for 3 minutes (CA group). Clinical assessments were taken at baseline and at 6 months. The differences between treatments were not statistically significant. In the central area of the recession, the mean percentage of root coverage was 81.7% corresponding to a mean percentage of 79.3% and 84.0% for the TTC-HCl and the CA group, respectively. In the test group, 6 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 57.8%. In the control group, 8 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 43.6%. The mean surface area of root exposure was reduced from 11.53 mm2 and 13.30 mm2 to 0.34 mm2 and 0.29 mm2 for the TTC-HCl group and the CA group, respectively. This reduction corresponds to a mean percentage of 97.4% root coverage for both groups. Within the limits of this study, the results indicate that tetracycline hydrochloride and citric acid root conditioning have comparable clinical effects in root coverage surgical therapy. The data also suggest that the measurement of the surface area of the recession is a more accurate criterion in the evaluation of the mean percentage of root coverage than a single central vertical linear measurement.

Bone regeneration in extraction sites after immediate placement of an e-PTFE membrane with or without a biomaterial. A report on 12 consecutive cases

The efficacy in restoring a buccal dehiscence after tooth extraction has been studied in 12 consecutive cases using guided bone regeneration with (6 patients) or without (6 patients) a biomaterial (DFDBA or Bio Oss) beneath an e-PTFE membrane. A correlation between the clinical impression of density at drilling time and the histological signs of bone formation has been evaluated too. The membrane was removed after 6 or 9 months and a biopsy was performed. Clinically, GBR was highly predictable for regeneration of the alveolar bone after tooth extraction with buccal dehiscence. The histology fully confirmed the clinical and radiographical results, showing bone formation in all cases with individual variations in the amount of bone formed. 6-month biopsies from the membrane sites had lamellar bone with large medullary spaces, while a good bone density was observed at 9 months. The membrane/biomaterial sites demonstrated mineralization and large amounts of allograft at 6 months. Thus, bone regeneration seems to take more time when grafting material is used.

Treatment of interproximal angular defects by guided tissue regeneration: 1 year follow-up

The periodontal regeneration of interproximal bone defects of the posterior teeth produced by guided tissue regeneration (GTR), with expanded Polytetrafluoroethylene barrier membranes and conventional therapy, was clinically evaluated in 20 intrabony periodontal defects in 10 patients. The material included the presence of at least two proximal angular lesions for the same patient, probing pocket depth > or = 6 mm, bone defect depth > or = 3 mm, and 2-wall defects with crestal involvement relative to the tooth circumference ranging from 90 to 270 degrees. Healing was clinically evaluated by surgical re-entry of GTR-treated sites (10 sites) and debridement only sites (10 sites) 1 year after initial surgery following a strict plaque control regimen. A significant correlation was observed between probing depth reduction, attachment gain and defect depth (test sites); there was increased bone fill in GTR-treated lesions of 2.95 +/- 1.3 mm corresponding to a 69.4% improvement compared to control sites, and 1.3 +/- 1.0 mm corresponding to a 32% improvement (P < 0.0039). The results demonstrated that bone regeneration is highly reliable, as compared to conventional therapy, in cases of severe periodontal bone loss from posterior teeth provided that the principles of GTR are applied.

[Tolerance of amlodipine in left ventricular dysfunction of ischemic origin]

The aim of this study was to assess the effects of amlodipine on left ventricular function at rest and on effort, at least 30 days after myocardial infarction. The 30 patients included in the study had resting isotopic ejection fractions of 40 to 60%. At inclusion and after 15 days treatment with 10 mg of amlodipine, the patients underwent exercise stress testing with a standard Bruce protocol and resting and exercise isotopic left ventricular ejection fractions were measured. The association of betablockers was allowed but vasodilator therapy was prohibited. During the second exercise stress test, the duration of exercise increased (437 +/- 167 to 518 +/- 154 s; p < 0.002) and the work level rose from 140 +/- 56 to 169 +/- 60 Watts; p < 0.04. The number of electrically positive tests did not change significantly (33 vs 26.7%; NS). The resting ejection fraction did not increase after 15 days treatment with amlodipine (47.4 +/- 6.7 vs 48.3 +/- 8.9%; NS). Similar results were observed with respect to the exercise ejection fraction (51.4 +/- 10.4 vs 52.6 +/- 8.6%; NS). These patients may however be divided into two subgroups. In the first subgroup of 10 patients, the resting ejection fraction rose by more than 5% with amlodipine whereas the exercise ejection fraction remained unchanged (54.4 +/- 7.7% vs 54.5 +/- 7.5% with amlodipine). In the second subgroup of 20 patients, the resting ejection fraction decreased slightly with amlodipine (48 +/- 6.9% vs 45.3 +/- 8%; p = 0.04) but increased significantly on exercise (45.3 +/- 8% vs 51.7 +/- 9.1%; p < 0.0002). Therefore, amlodipine, a new generation calcium antagonist, does not induce any deleterious effect after myocardial infarction with mild left ventricular dysfunction.

Subepithelial connective tissue grafts in the treatment of gingival recessions. A comparative study of 2 procedures

Thirty (30) class I and class II recessions in 30 subjects were treated with a subepithelial connective tissue graft procedure. In one group (15 sites), the surgery was carried out in a traditional fashion: the epithelial collar of the graft was preserved and left exposed (CTG group). In the second group (15 sites), the epithelial collar of the graft was removed and the recession areas were conditioned with citric acid. The graft was then sutured and completely immersed under the facial flap which was coronally repositioned (CR group). Clinical assessments included probing depth, probing attachment level, surface area of the recession, and gingival width. These measurements were taken at baseline and at 6 months. In addition, an esthetic evaluation was done. The differences between treatments were not statistically significant except for the augmentation of gingiva (P < or = 0.05). Based on the midfacial measurements taken in the central area of the recession, the mean percentage of root coverage was 69.2%. In the CR group, 3 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 65.5%. In the CTG group, 5 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 94.4%. The mean surface area of root exposure was reduced from 13.82 mm2 and 13.67 mm2 to 2.15 mm2 and 2.34 mm2 for the CR group and the CTG group, respectively. One-hundred percent (100%) of good-to-moderate esthetic results were found by a panel of independent examiners; there was tendency toward better results in the CR group.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of radionuclide ventriculography during transesophageal atrial pacing in the diagnosis of coronary artery disease

Radionuclide ventriculography before, during, and after atrial transesophageal pacing was carried out in 15 patients with suspected coronary artery disease (CAD) and without myocardial infarction. All patients underwent coronary angiography. Ten patients (group 1) had a coronary lesion > 50% on at least one of the main coronary arteries. Five patients (group 2) had normal coronary arteries. Radionuclide left ventricular ejection fraction (LVEF) before pacing was 56 +/- 3% in group 1 and 59 +/- 3% in group 2 (NS). Radionuclide ventriculography during pacing was 45 +/- 4% in group 1 (P < 0.0001 vs basal in group 1) and 45 +/- 6% in group 2 (P < 0.01 vs basal in group 2, NS vs group 1 during pacing). Immediate postpacing ejection fraction did not differ in the two groups and was identical to the prepacing value. A quantitative regional wall motion analysis was performed in 105 segments. Regional radionuclide ventriculography was calculated in each segment as follows: end-diastolic counts-end-systolic counts/end-diastolic counts. The relative decrease in regional LVEF during pacing was more important in the 39 segments related to a narrowed vessel than in the 66 segments related to normal coronary artery (32 +/- 13% vs 13 +/- 10%, P < 0.0001). A more than 20% relative decrease in at least one segment during pacing occurred in 10 patients in group 1 (sensitivity 100%) and in 2 patients in group 2 (specificity 60%). In conclusion, global radionuclide ventriculography during transesophageal atrial pacing decreases in patients with and without CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Guided tissue regeneration around dental implants in immediate extraction sockets: comparison of e-PTFE and a new titanium membrane

To evaluate the efficacy of guided tissue regeneration around exposed implant threads, 16 implants were placed into fresh extraction sockets in beagle dogs. Polytetrafluoroethylene (e-PTFE) membranes and titanium membranes were used to cover the defects around implants. A control group did not receive any membranes. Results were evaluated histologically. The average gain in bone height was 2.1 mm for e-PTFE sites, 0.8 mm for titanium membranes, and 2.9 mm for control sites. The greatest gain in bone levels was seen for two sites that received e-PTFE membranes and remained covered for the entire evaluation interval. Within the limits of this study, clinical and histologic evidence demonstrated that, when primary coverage is maintained, the use of e-PTFE membranes can significantly enhance bone regeneration around implants.

Effectiveness of adjunctive irrigation in early periodontitis: multi-center evaluation

The purpose of this study was to determine the effect of daily water irrigation versus regular oral hygiene alone on gingival and periodontal health in periodontitis patients receiving supportive periodontal treatment. The study also sought to determine if there are enhanced benefits from using an antiplaque zinc sulfate rinse as an irrigant. One hundred fifty-five patients who have had periodontitis and had been treated either surgically or non-surgically completed the 6-month multi-center multi-national study. Patients with at least two 5 mm sites demonstrating bleeding on probing were assigned to 3 equal groups by balanced randomization. In all centers Group A (n = 57) performed regular oral hygiene only, and Group B (n = 58) irrigated with 500 ml water once daily after regular oral hygiene. Group C (n = 40) patients irrigated with a total of 500 ml once daily; following irrigation with 300 ml water, the patients then irrigated with an additional 200 ml with a zinc sulfate solution. The irrigants were diluted to provide the manufacturer's recommended daily dosage. The supragingival irrigation was performed with a commercially available oral irrigator. Bacterial measurements at baseline, 3 months, and 6 months were taken to determine the effect of irrigation on the target organisms and will be reported elsewhere. Gingival index: irrigation with water (Group B) was significantly better than normal oral hygiene (Group A) and irrigation with zinc sulfate (Group C) (P < 0.05) in reducing gingival inflammation. Bleeding on probing: significant reductions in bleeding on probing occurred for water (Group B) compared to normal oral hygiene (Group A) (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of thallium-201 myocardial scintigraphy after atrial transoesophageal pacing in patients with suspected coronary artery disease

Fifty-five patients with suspected coronary artery disease underwent planar thallium-201 myocardial scintigraphy after atrial transoesophageal pacing. Coronary angiography was carried out in all patients. Eighteen patients had no myocardial infarction, but a greater than 50% narrowing of at least one main vessel: initial hypoperfusion with redistribution at 4 h occurred in 16 patients (sensitivity 89%). Twenty-one patients had had a previous myocardial infarction: a reversible thallium defect was observed in 12 patients and an irreversible defect in the nine remaining patients. Sixteen patients had normal coronary arteries: a reversible thallium defect was observed in three patients (specificity 81%). After a mean follow-up of 22 +/- 13 months (range 6 to 40), 23 cardiac events occurred: cardiac death in one patient, unstable angina in three, and revascularization procedures for recurrent angina despite medical therapy in 19 (coronary artery bypass surgery in 7 and coronary angioplasty in 12). By univariate analysis, the predictors of future cardiac events were a history of previous myocardial infarction (odds ratio 5.5, P < 0.02), multivessel coronary artery disease (odds ratio 9.6, P < 0.0002), angina during atrial pacing (odds ratio 5.1, P < 0.05), abnormal scintigraphy (odds ratio 17.1, P < 0.001) and reversible perfusion defect after pacing (odds ratio 7.9, P < 0.002). By multivariate analysis, multivessel disease (P < 0.004) and reversible perfusion defect after pacing (P < 0.02) were the only independent predictors of future cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of thallium myocardial scintigraphy after exercise and transoesophageal atrial pacing in the diagnosis of coronary artery disease

Forty-nine patients admitted for assessment of chest pain underwent coronary angiography, planar Thallium 201 myocardial scintigraphy after submaximal exercise (TE) and transoesophageal atrial pacing (TAP). Early hypofixation with redistribution after 4 h indicated ischaemia. The criterion for a myocardial infarction (MI) was a fixed perfusion defect. Coronary angiography was carried out in all patients. Sixteen patients (group 1) had no MI and over 50% narrowing of at least one main coronary vessel. Ischaemia was noted in 10 of the 16 patients during exercise, and in 14 of the 16 patients during atrial pacing. The sensitivity for the prediction of coronary stenosis was 62% for TE and 87% for TAP. Nineteen patients (group 2) had had a previous MI. Reversible ischaemia was noted in 10 of the 19 patients during exercise, and in 11 of the 19 patients during TAP. Four of 14 patients with normal coronary arteries (group 3) had a reversible ischaemia with TE, and three of these same patients developed a positive scan with TAP. The respective specificities were 71% and 78%. Comparison of segmental hypoperfusion after TE and TAP gave identical results in 72 of the 80 segments studied in group I (90%), and in 88 of the 95 segments studied in group 2 (92%). The localizing value of TAP was good in left anterior descending (12 out of 18) and right coronary disease (16 out of 19), but poor in left circumflex stenosis (3 out of 9) misclassified as right coronary disease in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prevention of substance loss in an edentulous site: report of case combining gingival graft and coral particles]

Ridge collapse is often seen after tooth extraction and grafting procedure is used in this technique. This case report presents, after block section of two maxillary incisors, the use of an occlusal epithelio-connective tissue graft, followed by grafting of coral particles. Clinical results, six months post-operatively, show a total maintenance of edentulous ridge volume and height. A biopsy at the same interval shows fibrous tissue surrounding coral particles, giant cells in some areas, but also some areas of calcification.

[Maintenance therapy. Review of the literature]

The periodontal literature contains a paucity of articles dealing with the maintenance of periodontal health after active treatment. The difficulty in doing long term clinical studies relates to the lack of compliance among patients. Well controlled maintenance programs are the main consideration in obtaining a good prognosis over the long term.

Comparative effects of quinolones on human mononuclear leucocyte functions

The effects of three quinoline derivatives--pefloxacin, ciprofloxacin and ofloxacin--were investigated in mitogen-stimulated human peripheral blood mononuclear leucocytes (MNL). At concentrations of 50 mg/l or more, pefloxacin, ciprofloxacin or ofloxacin significantly inhibited MNL proliferation in response to phytohaemagglutinin. This inhibition was more marked with ciprofloxacin than pefloxacin or ofloxacin. To determine the possible mechanism(s) involved in the inhibition of MNL proliferation following exposure to pefloxacin, ciprofloxacin or ofloxacin, we assessed (1) interleukin-1 (IL-1) activity in supernatants from monocytes treated with the quinolones and (2) the effects of 2-mercaptoethanol (2-ME) a thiol compound which acts as an antioxidant agent and the effect of indomethacin (INDO) an inhibitor of prostaglandin E2 synthesis. 2-ME and INDO did not prevent the decrease in the proliferation. IL-1 activity was shown to be decreased for the same range of antibiotic concentrations as observed for the inhibition of MNL proliferation. Cellular viability of the MNL or monocytes was not modified by any of the quinolones at the concentrations tested. Taken together, these results suggest that pefloxacin, ciprofloxacin and ofloxacin act as immunomodulators. The mechanism involved with the cascade of events that leads to the lymphocyte proliferation and the clinical relevance need further investigation.

Freeze-dried skin allografts. A human clinical and histological study

Free gingival autografts still remain the most predictable method for creating attached gingiva. However, a need exists for sources of connective tissue other than the patient's own connective tissue. Yukna et al. have proposed freeze-dried skin (FDS) allografts as a substitute for gingival autografts. The purpose of the present study was to evaluate FDS allografts on humans, clinically and histologically. Ten FDS allografts and two free gingival (FG) autografts were performed on ten patients, two of them receiving both FDS and FG grafts. Clinical measurements were made before surgery, immediately after surgery and then 2 and 6 months after surgery. After 4 and 24 months, biopsies were performed on both FG and FDS grafts. Routine histologic staining was done. The results show a mean gain of attached gingiva of 0.32 mm with a range from 0 to 0.8 mm. Compared biopsies sections of FDS allografts and FG autografts show that the tissue obtained with the FDS allografts do not display the histomorphologic pattern of attached gingiva. The FDS allografts do not seem to represent a good substitute to free gingival autografts. However, they might be used successfully as a biological bandage.