Binding of DNA by a dinitro-diester calix[4]arene: denaturation and condensation of DNA.

A study of a dinitro-diester calix[4]arene (5,17-(3-nitrobenzylideneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene) interaction with calf-thymus DNA was carried out using several techniques. The measurements were done at various molar ratios X=[calixarene]/[DNA]. Results show diverse changes in the DNA conformation depending on the X value. Thus, at low macrocycle concentrations, the calixarene binds to the polynucleotide. This interaction, mainly in groove mode, weakens the hydrogen bonds between base pairs of the helix inducing denaturation of the double strands, as well as condensation of the macromolecule, from an extended coil state to a globular state. An opposite effect is observed at X molar ratios higher than 0.07. The de-condensation of DNA happens, that is, the transition from a compact state to a more extended conformation, probably due to the stacking of calixarene molecules in the solution. Results also show the importance of making a proper choice of the system under consideration.

Human exposure to rabid free-ranging cats: a continuing public health concern in Pennsylvania.

Rabid free-ranging cats have been a public health concern in Pennsylvania since raccoon variant rabies first was recognized in the state in the early 1980s. Over the last decade, between 1.5 and 2.5% of cats submitted to Pennsylvania's state laboratories for rabies testing have been positive. In this report, we describe the extent of rabies in free-ranging cats in Pennsylvania. We also present two examples of human exposure to rabid free-ranging cats that occurred in Pennsylvania during 2010-2011 and the public health actions taken to address rabies exposure in the humans and animals. We then describe the concerns surrounding the unvaccinated and free-ranging cat population in Pennsylvania and possible options in managing this public and animal health problem.

A multi-state Salmonella Typhimurium outbreak associated with frozen vacuum-packed rodents used to feed snakes.

From December 2005 through January 2006, the Minnesota Department of Health (MDH) identified four human clinical isolates of Salmonella Typhimurium that were indistinguishable by pulsed-field gel electrophoresis (PFGE). During routine interviews, three of the cases reported attending the same junior high school and two handled snakes in the science classroom. MDH collected environmental samples from the school's science classroom for Salmonella culturing; these included environmental samples and frozen vacuum-packed mice purchased over the internet to feed the classroom snakes. Through PulseNet, a national molecular subtyping surveillance network for enteric bacteria, 21 human S. Typhimurium isolates with indistinguishable PFGE patterns were identified in the United States since December 2005. Each state determined whether these human cases had recent exposure to snakes fed vacuum-packed rodents. Texas state officials conducted tracebacks of the vacuum-packed mice and collected samples at the breeding facility. Nineteen of 21 cases were interviewed, and seven reported contact with frozen vacuum-packed rodents from the same internet-based supplier in Texas. In Minnesota, the outbreak PFGE subtype of S. Typhimurium was isolated from the snakes, frozen feed rodents, and the classroom environment. Three human cases were identified in Michigan, Pennsylvania, and Wyoming. The outbreak PFGE subtype of S. Typhimurium was isolated from the Pennsylvania case's frozen rodents and the Michigan case's pet snake. The outbreak PFGE subtype of S. Typhimurium was also isolated from the supplier's rodent facility. This was a S. Typhimurium outbreak associated with frozen rodents. Human transmission likely occurred through direct contact with snakes and contaminated environmental surfaces. This report represents the second recent multi-state salmonellosis outbreak associated with commercially distributed rodents. Stronger oversight of the commercial rodent industry is warranted.

Changes in alveolar bone height and width following ridge augmentation using bone graft and membranes.

BACKGROUND: Clinical observation suggests the amount of bone height and width created during guided bone regeneration (GBR) to augment alveolar ridges is not retained during healing. A study was designed to determine: 1) whether the amount of osseous structure 4 months postoperatively after GBR was significantly less than the amount surgically created; and 2) if this change was uniform over the area treated. METHODS: Nineteen extraction sites (10 patients) were treated with GBR prior to placing endosseous implants. Allograft (DMFDB) and a bioabsorbable membrane were employed. Standardized measurements were taken of alveolar height and width 1) prior to augmentation; 2) after placement of graft and membrane; and 3) following 4 months of healing. Width measurements were taken 3 mm, 5 mm, and 10 mm from the crest at 3 intervals: the mesio-distal midpoint of the edentulous area and 3 mm mesial and distal to the midpoint. Height measurements were recorded at the mesio-distal midpoint and points 3 mm mesial and distal to the midpoint. RESULTS: Loss in width of supplemented bone after 4 months of healing ranged from 52.1% to 58.0% 3 mm from the crest, 47.6% to 67.4% 5 mm from the crest, and 39.1 % to 46.7% 10 mm from the crest. Loss of augmented height averaged 14. 7% in the center of the edentulous area but ranged from 60.5% to 76.3% 3 mm mesial and distal to the midpoint. CONCLUSIONS: The results indicate significant non-uniform loss of augmented alveolar height and width during GBR healing. The implications of these findings impact preoperative augmentation planning for endosseous implantology.

The incubation period of hantavirus pulmonary syndrome.

In 1993 Sin Nombre virus was recognized as the cause of hantavirus pulmonary syndrome (HPS) and the deer mouse (Peromyscus maniculatus) was identified as the reservoir host. Surveillance by the Centers for Disease Control and Prevention and state health departments includes investigation to determine the likely site(s) and activities that led to infection, an environmental assessment of the home and workplace, and possibly rodent trappings at these sites. As of December 31, 1998, there were 200 confirmed cases from 30 states (43% case-fatality ratio). The national HPS case registry was examined to determine the incubation period of HPS. Review of 11 case-patients with well-defined and isolated exposure to rodents suggests that the incubation period of HPS is 9 to 33 days, with a median of 14-17 days. Case investigations allow a better understanding of the incubation time of HPS and may define high-risk behaviors that can be targeted for intervention.

Regeneration of intrabony defects: comparing e-PTFE membrane vs. decalcified freeze dried bone allograft--a pilot study.

The purpose of this study was to compare the amount of clinical attachment gained when using an expanded polytetrafluoroethylene (e-PTFE) membrane versus the placement of a decalcified, freeze-dried bone allograft (DFDBA) in human deep intrabony defects. Ten 2- and 3-wall intrabony defects were treated with scaling and root planing followed by flap surgery and placement of either an e-PTFE membrane or a DFDBA. The clinical parameters, clinical attachment level (CAL), probing depth (PD) and recession, were evaluated at baseline, following oral hygiene instructions and scaling and root planing, and at 6 and 9 months post-operatively. The e-PTFE group demonstrated an increased CAL of 3.2 mm at 6 months and 3.4 mm at 9 months while the DFDBA group manifested a gain of 2.2 mm at 6 months and 2.6 mm at 9 months. The e-PTFE group had a 6.6 mm decrease in PD at 6 months and 6.2 mm at 9 months while the DFDBA group had a decrease of 4.0 mm and 4.4 mm at 6 and 9 months respectively. The amount of gingival recession was 1.6 mm for both groups at 6 months and slightly less for the PTFE group at 9 months. It was concluded that both treatment groups resulted in a clinically and statistically significant improvement over baseline measurements in clinical attachment gain and PD reduction. No statistical significance could be demonstrated between the two groups. The number of subjects and sites treated by the two treatment modalities--e-PTFE and DFDBA--was too small to conclude that the treatments gave comparable results. A larger sample size is necessary in order to establish whether or not a statistically significant difference exists between groups.

Osseous repair of a lateral periodontal cyst.

THE LATERAL PERIODONTAL CYSTS is a slow-growing radiolucent, developmental lesion occurring most frequently in males during the sixth decade. As part of the differential diagnosis, it must be distinguished from the collateral keratocyst and the gingival cyst of adults as well as other entities. Speculation remains as to the lateral periodontal cyst's developmental origin. Whether it is from reduced enamel epithelium, remnants of dental lamina, or cell rests of Malassez remains to be determined. The following longitudinal case report describes the review of literature and clinical and histologic findings as well as unusual treatment of a through-and-through perforating lateral periodontal cyst. Due to the large bony defect left after the cyst's removal, a decalcified freeze-dried bone graft was placed to close the defect. The repair of the lesion was followed for 30 months.

Histological, clinical, and digital subtraction radiographic evaluation of repair of periodontal defects resulting from mechanical perforation of the chamber floor using ePTFE membranes.

The aim of this study was to test the hypothesis that a biocompatible membrane, when placed between the gingiva and cortical bone in teeth with periodontal defects that occurred following mechanical endodontic perforation, would facilitate greater regeneration than in control sites not treated with guided tissue regeneration. One beagle dog with a healthy periodontium was used in the study. The maxillary right first and second molars and the mandibular left first and second molars acted as the experimental group in which furcation perforations were treated by guided tissue regeneration. The maxillary left and mandibular right first and second molars served as the controls in which furcation perforation lesions were only treated by open flap debridement. Clinical, histological, and standardized radiographic evaluation showed significant differences between the test and control groups. In addition, digital subtraction radiography revealed a gain in alveolar bone height and increased density at all experimental sites, and a loss at all control sites. Histological evaluation showed extensive regeneration of both alveolar bone and connective tissue at experimental sites, but none at control sites. The results of this study suggest that the use of guided tissue regeneration in furcation lesions produced by endodontic perforations will result in significant new bone and connective tissue attachment.

Effect of an enzymatic rinse on salivary levels of Streptococcus mutans and lactobacilli in periodontally treated patients.

Root surface caries is prevalent in patients with both treated and untreated periodontal disease. The major etiologic factor has been identified as microbial plaque. In periodontally treated patients, significantly higher root caries prevalence and incidence have been found in patients with high levels of Streptococcus mutans and Lactobacilli in saliva. Reducing the levels of S. mutans and Lactobacilli in saliva may lower the risk of root caries development. The purpose of this investigation was to determine the effect of an oral enzymatic rinse on the salivary counts of S. mutans and Lactobacilli in periodontally treated patients. Fifteen adult subjects participated in a double-blind, cross-over designed clinical trial. Each subject had previously undergone comprehensive periodontal therapy and had been maintained on a regular program of supportive periodontal therapy. Paraffin-stimulated whole saliva was collected from each participant. Each subject was then randomly given either the enzymatic rinse product or a control rinse and instructed to rinse with one tablespoonful twice a day for 2 weeks, after which saliva samples were taken. After a washout period, salivary samples were again taken, and the subjects received the alternate rinse product. Two weeks later, final salivary samples were taken. The salivary samples were serially diluted and incubated aerobically on selective culture media. S. mutans and Lactobacilli were counted on the basis of colonial morphology. Pretreatment and posttreatment salivary counts of S. mutans and Lactobacilli were analyzed using the Wilcoxon matched-pairs signed-rank test at the 5% level of significance. Analysis of data revealed that neither the test nor the control rinse significantly lowered salivary counts of either species in the sample population.

Screening for periodontal disease: radiographs vs. PSR.

This study compares the evaluation of periodontal health using bone levels measured on periapical and bitewing radiographs with clinical parameters, such as periodontal screening and recording, gingival indexes, probing depths and attachment levels. The authors found that bitewing radiographs taken within six months of the clinical examination correlated better with the clinical data than older radiographs. However, they concluded that, overall, radiographs are not highly reflective of periodontal status. PSR scores, by contrast, showed significant associations with probing depths and attachment levels. The results support use of PSR as a screening tool for periodontal diseases.

Assessment of periodontal status with PSR and traditional clinical periodontal examination.

The system of peridontal screening and recording was developed by the American Dental Association and the American Academy of Periodontology to simplify early detection of periodontal pathology. The authors evaluated the results of PSR against those of a conventional periodontal examination in 24 subjects, each of whom had a minimum of 18 natural teeth. The results of this study suggest that the PSR examination, while a useful screening tool, could be improved to further enhance its identification of patients with peridontal diseases.

Clinical plaque removal performance of two manual toothbrushes.

A single-blind, cross-over design clinical study was conducted to compare the plaque removal efficacy of the Colgate Precision Full Head soft and the Crest Complete soft toothbrushes. A total of 72 adult male and female subjects who met the inclusion/exclusion criteria completed the study. Each subject refrained from brushing for 24 hours, and was screened for dental plaque on the facial and lingual surfaces of all natural teeth using the Rustogi, et al. refinement of the Modified Navy Plaque Index (Rustogi, et al. Index). Subjects were then stratified according to the MPI and randomly assigned to one of two groups. Subjects returned one week later having abstained from all oral hygiene procedures for a 24-hour period. At this visit, each subject was evaluated for plaque, then brushed with his/her assigned toothbrush for 60 seconds, and again scored for plaque after brushing. Subjects were instructed to resume their normal routine and return to the clinical site one week later. At this time, the alternate toothbrush was assigned to each group in a cross-over design. Plaque evaluations and toothbrushing procedures were again performed. Data were statistically analyzed, and the Colgate Precision toothbrush was demonstrated to be significantly more effective (p < 0.01) in removing whole mouth, gumline, and interproximal area plaque.

A clinical comparison of plaque removal performance of three manual toothbrushes.

A clinical study was performed to evaluate and compare the plaque-removal performance of a recently introduced, computer-designed manual toothbrush with that of two commercially available products; the Oral-B 40 and the Reach Full-Head soft toothbrushes. Seventy-five adult male and female subjects participated, each refraining from toothbrushing for twenty-four hours. Plaque was scored according to the Rustogi, et al. refinement of the Modified Navy Plaque Index. Following screening, the subjects were divided into three balanced groups on the basis of initial plaque scores. Each group, in an alternate weekly cross-over design, used each of the three toothbrushes. At Visit 1, each group, having refrained from toothbrushing for twenty-four hours, was evaluated for plaque before brushing for sixty seconds with the assigned toothbrush, after which plaque was again scored. At Visit 2 one week later, the same procedure was followed except for the assignment of a different toothbrush. The same procedure was employed for Visit 3. On completion of the study, the data were subjected to statistical analyses which indicated that the Colgate Precision Full Head soft toothbrush removed significantly more plaque than either of the other two toothbrushes.

Reconstruction of the severely atrophic maxilla with autogenous iliac bone graft and hydroxylapatite/decalcified freeze-dried bone allograft in the same patient: a preliminary report.

Procedures to augment the severely atrophic maxilla using sinus lift techniques have been increasingly used for endosseous implant placement. A case report is presented in which a patient had a severely resorbed maxilla bilaterally. A situation developed during the course of treatment which created a unique opportunity to compare an autogenous iliac graft on one side with a hydroxylapatite/freeze-dried bone allograft on the other.

Effect of a twice daily 0.12% chlorhexidine rinse on the oral health of a geriatric population.

The inhibitory effect of a chlorhexidine rinse on gingival inflammation and plaque accumulation has been well documented. The purpose of this study was to determine whether a twice daily oral rinse with 0.12% chlorhexidine will resolve denture-associated inflammation in a geriatric population. Thirty-six subjects, average age 83 years, were randomly divided into two groups, active and control, and further stratified into three subgroups, removable partial dentures, complete overdentures and lacking a removable prosthesis. Gingival (Löe and Silness '63) and plaque (Silness and Löe '64) indexes were performed on teeth Nos 3, 9, 12, 19, 25 and 28 at baseline and at 60 days. The subjects, following baseline measurements, were required to rinse twice daily for 30 seconds with either a 15 ml solution of 0.12% chlorhexidine or a placebo and instructed to continue their normal oral hygiene routine. The data were statistically analyzed. When active and control groups were compared, either in total or within their stratified subdivisions, significant differences were observed (P less than 0.001). The active group had a 10.27% and 16.68% reduction in the gingival and plaque indexes, respectively, compared to insignificant changes in the control groups. It was concluded that although chlorhexidine proved effective in reducing inflammation and plaque scores, this reduction was not influenced by the type of prosthesis worn.

Antiplaque efficacy of a triclosan/copolymer prebrush rinse: a plaque prevention clinical study.

A 5-day, double-blind parallel clinical study was conducted to determine the antiplaque efficacy of a pre-brush rinse containing 0.03% triclosan and 0.125% of a copolymer of polyvinyl methyl ether maleic acid as compared to a matching matching placebo pre-brush rinse. A total of 114 subjects were stratified into two balanced groups according to baseline Quigley-Hein Plaque Index scores. Each group was randomly assigned to use either the triclosan/copolymer pre-brush rinse or the placebo pre-brush rinse. All subjects received a thorough oral prophylaxis at the start of the study. They rinsed their mouths twice daily (mornings and evenings) for 1 minute with 15 cc of their assigned pre-brush rinse. Immediately after rinsing, subjects brushed their teeth for 30 seconds with a commercially-available dentifrice containing 0.76% sodium monofluorophosphate and a soft-bristled toothbrush. The morning rinsing/brushing procedure was done under supervision at the clinical facility. The evening rinsing/brushing procedure was done at home. After 5 days' use of their assigned pre-brush rinse, subjects were evaluated for plaque formation using the modified Quigley-Hein Plaque Index scoring system. As compared to the matching placebo pre-brush rinse, the results showed: 1) The triclosan/copolymer pre-brush rinse provided a 28.15% reduction in plaque formation on all surfaces of the teeth. This reduction was statistically significant (P less than 0.001); 2) The triclosan/copolymer pre-brush rinse provided a 50% reduction in plaque formation on the "more difficult to brush" surfaces of the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a dentifrice containing triclosan and a copolymer on plaque formation and gingivitis.

A total of one hundred twenty-one (121) adult male and female subjects completed a 6-month, double-blind clinical study comparing the effect on supragingival plaque formation and gingivitis of a dentifrice containing 0.3% Triclosan and 2.0% of a copolymer of methoxyethylene and maleic acid to a placebo dentifrice. Both the Triclosan/copolymer and placebo dentifrices contained 0.243% sodium fluoride in a silica base. Subjects were stratified into two balanced groups according to baseline plaque and gingivitis scores. They then received an oral prophylaxis and were assigned to use either the Triclosan/copolymer dentrifrice or the placebo dentifrice for the next 6 months. Subjects were evaluated for supragingival plaque formation and gingivitis after 3 and 6 months' use of the dentifrices. After 6 months, the Triclosan/copolymer dentifrice was shown to provide a 32.32% statistically significant reduction (99% level of confidence) in supragingival plaque formation, as compared to the placebo dentifrice. Also, after 6 months, the Triclosan/copolymer dentifrice was shown to provide a 25.64% statistically significant reduction (99% level of confidence) in gingivitis, as compared to the placebo dentifrice. It thus can be concluded from this clinical study that the twice daily use of the dentifrice containing 0.3% Triclosan and 2.0% of a copolymer in a 0.243% sodium fluoride/silica base provides statistically significant reductions in both supragingival plaque formation and gingivitis.