Synthesis, Biological Evaluation, and Docking Studies of Open-Chain Carbohydrate Amides as Acetylcholinesterase Inhibitors.

INTRODUCTION: Alzheimer's disease is a multifactorial syndrome, which is not yet fully understood, causing memory loss, dementia, and, ultimately, death. Acetylcholinesterase inhibitors are the mainstay drugs that are used in disease-symptomatic treatment. In this work, we report a new synthetic route yielding sugar amides as low to moderate acetylcholinesterase inhibitors. METHODS: Commercially available diacetone glucose was converted into perbenzyl D-glucono-1,4- lactone, which reacted with aromatic or aliphatic amines to afford the corresponding new amides in a high isolated yield. Docking studies of the most promising hydroxybutylamide and benzylamide were performed to assign binding interactions with acetylcholinesterase and determine the key features for bioactivity. RESULTS: The inhibitors are accommodated in enzyme gorge, blocking the access to Ser203 mainly due to π-π stacking interactions of sugar benzyl groups with the aromatic gorge residues, Tyr337 and Tyr341 for both inhibitors and Trp439 only for the hydroxybutylamide. CONCLUSION: Bonding is also significant through sugar interaction with the residues Tyr124 and Ser125-OH in both inhibitors. Flexibility of these open-chain structures seems to be quite relevant for the observed binding to acetylcholinesterase.

Preparation time and perceptions of Brazilian specialists and dental students regarding simulated root canals for endodontic teaching: a preliminary study.

The aim of this preliminary study was to evaluate the desirability of alternative models of artificial teeth versus extracted natural teeth for use in preclinical dental education. Specifically, the study was designed to compare the preparation time and perceptions of difficulty of undergraduate dental students and endodontists in carrying out root canal preparations on resin models (both clear and opaque) and extracted natural teeth. Twenty participants-ten fifth-year students at a Brazilian dental school and ten endodontists with at least five years' experience in the specialty-performed root canal instrumentation on two samples of each model. Preparation times were recorded, and the participants completed a questionnaire about the anatomical and physical characteristics of these models. The results showed that the time required for performing endodontic procedures in the natural teeth was higher than in the alternative models. The perceptions of the students and specialists regarding some topics on the questionnaire were significantly different. The students had more positive opinions about artificial teeth made of opaque resin, while the specialists had more positive opinions about simulated root canals in clear resin blocks. This study suggests that neither of the alternative models fulfilled requirements to replace natural teeth in endodontic teaching; improvements are still necessary to accomplish this goal.

Apical periodontium response to enamel matrix derivative as an intracanal medication in rat immature teeth with pulp necrosis: radiographic and histologic findings.

INTRODUCTION: The aim of this study was to evaluate the enamel matrix derivative (EMD) biomaterial in nonvital immature teeth. METHODS: To arrest root development, pulpectomies were performed in the lower first molars of 36 4-week-old rats; the cavities were left exposed to the oral environment for 3 weeks. Then, chemical disinfection was performed, and triple antibiotic paste (TAP) or EMD was applied in the root canals. A control group did not receive any treatment. Radiographic and histological data were evaluated after 3 and 6 weeks. RESULTS: At 3 weeks, TAP promoted a milder inflammatory response and increased root lengths compared with the control group. At 6 weeks, root development and reduced periapical lesions could be observed in both test groups, mainly because of the deposition of a cementum-like tissue. EMD promoted narrower canals compared with TAP (P < .05). CONCLUSIONS: EMD deserves attention as a potential tool in the treatment of nonvital immature teeth. The ingrowth of cementum-like tissues into canal spaces favored dental wall thickness and may contribute to tooth resistance and support.

Teeth with double internal inflammatory resorption: report of two cases.

Internal inflammatory resorption is an uncommon condition, which requires the presence of necrotic and infected pulp tissue within the coronal portion of the root canal system as well as inflamed pulp tissue apical to the resorptive defect. The defect usually appears as a bowl-shaped radiolucency within the tooth root. Most cases are asymptomatic and many cases are only seen once the entire pulp has necrosed and all of the root canal system is infected resulting in apical periodontitis. The two cases presented are unusual in that they both had two distinct areas of internal inflammatory resorption. It is hypothesised that the more coronal lesion occurred first and then it ceased to continue resorbing the root in that position as the 'necrotic, infected front' moved apically at which time a second resorptive defect developed. The management, using different approaches, of these two cases of 'double internal inflammatory resorption' is described.

Use of a bottle warmer to increase 4% sodium hypochlorite tissue dissolution ability on bovine pulp.

The aim of this study was to evaluate the tissue dissolution ability of 4% sodium hypochlorite at increasing temperatures with the use of a baby bottle warmer. Twenty pieces of bovine pulp tissue from freshly extracted incisors and canines were weighted and randomly distributed among four groups in accordance to the exposure to 4% sodium hypochlorite at different temperatures: group C--room temperature (20.5 degrees C--control); group T1--45 degrees C; group T2--60 degrees C; group T3--75 degrees C. The samples were placed within test tubes when the solution reached the desired temperature. Time taken for the dissolution was recorded. One-way anova with logarithmical transformation and Duncan post-hoc was used (P = 0.05). There was a statistically significant increase in speed of pulp dissolution from group T1 to group C and from groups T2 and T3 to group T1; group T2 and T3 displayed similar dissolution speeds.

Urological manifestations of chronic schistosomal myeloradiculopathy.

OBJECTIVE: To describe the clinical and urodynamic features of patients with chronic voiding dysfunction secondary to schistosomal myeloradiculopathy (SM), as the clinical involvement of the spinal cord is a well recognized complication of Schistosomiasis mansoni infection. PATIENTS AND METHODS: We reviewed the records and urodynamic studies of 26 consecutive patients (17 males and nine females, aged 8-58 years) with chronic neurological and urinary symptoms secondary to SM. The voiding function history, radiological and urodynamic findings and therapeutic approaches were reviewed. Patients with and without upper urinary tract complications were compared in terms of age, duration of voiding dysfunction and urodynamic pattern. RESULTS: The most common urinary symptoms were difficulty in emptying the bladder (17 patients, 65%), urinary incontinence (14, 54%), and urgency and frequency (13, 50%). Laboratory and radiographic evaluation showed urinary tract infection in eight (30%) patients, bilateral hydronephrosis in five (19%) and bladder calculi in five (19%). Urodynamics showed detrusor overactivity with detrusor-external sphincter dyssynergia (DESD) in 14 patients (54%), detrusor arreflexia in six (23%), detrusor overactivity with no dyssynergia in four (15%), and detrusor underactivity in two (8%). Comparing patients with and without upper tract complications showed no differences in age and duration of urinary symptoms, but there was a significant association of detrusor overactivity with DESD and upper urinary tract complications (P = 0.04). Urological management consisted of antibiotics, clean intermittent catheterization, anticholinergic medication and stone removal, as appropriate. Conservative treatment failed in three patients and they required an injection with botulinum-A toxin into the detrusor (two) or ileocystoplasty (one). CONCLUSION: Patients with chronic SM behave clinically like those with other causes of spinal cord disease and neurogenic bladder dysfunction requiring lifelong surveillance. The severity of illness in these patients should re-emphasize the need for early recognition and treatment of this condition, to prevent or reverse the neurological deficits.