Biological evaluation of calcium alginate microspheres as a vehicle for the localized delivery of a therapeutic enzyme

Gaucher disease (GD) is caused by the decreased activity and/or stability of the lysosomal enzyme glucocerebrosidase (GCR). The available treatment consists in the intravenous administration of exogenous GCR, and is effective in reverting most of the symptoms. However, in terms of bone pathology, which is among the most disabling manifestations, a slow and incomplete response is observed, indicating that adjuvant therapies are necessary to consistently restore GCR activity in bone and accelerate regeneration. In this study, calcium alginate microspheres were analyzed as a vehicle for localized GCR delivery to bone. Results demonstrated that the entrapped enzyme retained full activity and exhibited a broader pH-dependent activity profile, compared to that of free-GCR, with improved stability at physiological pH. GCR release profile was established, and it was demonstrated that GCR could be released in a sustained manner. The biological behavior of the system was evaluated by analyzing the uptake of released GCR by GCR-deficient cells from GD patients, using different techniques: GCR activity measurements, radiolabeling, and cellulose acetate electrophoresis. Results demonstrated that GCR was internalized by cells significantly enhancing the residual enzymatic activity. To achieve an activity reconstitution level comparable to that obtained using free-GCR, only half of the dose was required with entrapped-GCR.     

Assisted hatching improves implantation rates on cryopreserved-thawed embryos. A randomized prospective study

Sir, Gabrielsen et al. (2004) evaluated the impact of assisted hatchingin cryopreserved human embryo transfers and reported an implantationrate of 11.4% in the assisted hatching group and 5.8% in thecontrol group (P<0.05; Table I     

Instrumental learning within the rat spinal cord: localization of the essential neural circuit

Following spinal transection of the upper thoracic spinal cord, male Sprague-Dawley rats given legshock whenever a hindlimb is extended learn to maintain the leg in a flexed position. The region of the cord that mediates this instrumental learning was isolated using neuroanatomical tracing, localized infusion of lidocaine, and surgical transections. DiI and Fluoro-Gold microinjection at the site of shock application labeled motor neuron bodies of lamina IX in the lower lumbar region. Local application of the Na-super++ channel blocker lidocaine disrupted learning when it was applied over a region extending from the lower lumbar (L3) to upper sacral (S2) cord. The drug had no effect rostral or caudal to this region. Surgical transections as low as L4 had no effect on learning. Learning also survived a dual transection at L4 and S3, but not L4 and S2. The results suggest that the essential neural circuit lies between L4 and S3.     

Increased interleukin-18 in patients with juvenile idiopathic arthritis and early attachment loss

BACKGROUND: Patients with juvenile idiopathic arthritis (JIA) have been shown to have incipient attachment loss (AL) more frequently than systemically healthy individuals. This study investigated neutrophil activity and proinflammatory cytokines in these patients and aged-matched controls. METHODS: Elastase activity, measured with a low molecular weight substrate (S-2484), and interleukin-1beta (IL-1beta), measured with the enzyme-linked immunosorbent assay (ELISA), were analyzed in the gingival fluid of 38 patients with JIA and 29 controls. IL-1beta and interleukin-18 (IL-18) were measured with ELISA in the serum of the same groups. Subgingival plaque was analyzed by DNA probes to detect 12 bacteria. RESULTS: Significantly elevated serum levels of IL-1beta and IL-18 were found in the JIA group. No differences were found in the gingival fluid levels of elastase and IL-1beta between groups, or in the frequency of subjects positive to most of the bacteria analyzed, except F. nucleatum, C. rectus, P. micros, and S. intermedius, which were significantly more frequent in the control group. When the JIA group was subdivided according to the presence/absence of AL, IL-18 was significantly increased in the JIA subgroup with AL compared to those without it. There were no differences in the subgingival microbiota between the subgroups. CONCLUSION: The findings of increased serum IL-18 and IL-1beta in patients with JIA accompanied by a similar subgingival microbiota suggest that the increased frequency of incipient attachment loss observed in these patients might be due to their altered systemic inflammatory response, making them more susceptible to periodontal disease.     

Clinical and histologic evaluation of the periodontal response to restorative procedures in the dog

This study evaluated, in the dog, the periodontal response to resin-modified glass-ionomer cement or amalgam restorations placed in surgical windows and left for 124 days. Plaque control was performed in half of the sites. Histologic analyses showed that sites restored with amalgam were consistently more inflamed than sites restored with resin-modified glass-ionomer. Plaque control was associated with less inflammation in both cases. Some sites restored with resin-modified glass-ionomer presented bone repair and a connective tissue lining. The inflammatory response of the periodontium to resin-modified glass-ionomer restorations is less pronounced than that associated with amalgam restorations.     

Hybrid layer thickness and morphology: the influence of cavity preparation with Er:YAG laser

Dentinal surfaces prepared with Er:YAG laser have significantly different characteristics from those prepared with conventional instruments. Different hybrid layer morphologies and thicknesses occur, which may result in differences in the quality of restorations placed on dentinal surfaces prepared with a diamond bur when compared with using an Er:YAG Laser. This study compared the hybrid layer thickness and morphology formed utilizing Scotchbond Multipurpose Plus (SBMP) on dentin prepared with a diamond bur in a high speed handpiece and dentin prepared with an Er:YAG laser. Flat dentin surfaces obtained from five human teeth were treated with the two methods and then with the dentin adhesive system according to the manufacturer's instructions. After a layer of composite was applied, the specimens were sectioned, flattened, polished and prepared for SEM observation. Ten different measurements of hybrid layer thickness were obtained along the bonded surface in each specimen. Results showed that SBMP produced a 3.43 +/- 0.75 microm hybrid layer in dentin prepared with a diamond bur. This hybrid layer was regular and constantly found. In the laser group, the dentin adhesive system produced a 1.54 +/- 0.35 microm hybrid layer that was very irregular and not found constantly. Statistical analysis of variance (p < 0.05) showed that there was a statistically significant difference between the groups. These data indicate that the Er:YAG laser, with parameters used in the experiment, is not a preparation method that allows for a thick hybrid layer formation, which is in opposition to using a diamond bur in a high speed turbine.     

Screening behavior of individuals at high risk for colorectal cancer

BACKGROUND AND AIMS: Periodic colonoscopy is an effective means of reducing the incidence and mortality of colorectal cancer in individuals with a family history of the disease. The aims of this study were to determine the degree of compliance and to identify the factors related significantly to noncompliance with periodic screening in this high-risk population. METHODS: A total of 178 individuals who had undergone genetic counseling for colorectal cancer between 1986 and 1998 and who had been advised to undergo periodic screening because of familial colorectal cancer (FCRC) or hereditary nonpolyposis colorectal cancer (HNPCC) were invited to complete a self-report questionnaire on psychosocial issues and screening experiences. Compliance data were derived from medical records and via self-report. RESULTS: A total of 149 individuals (84%) participated in the study. Noncompliance with screening advice was rare (in 3% of cases), but significant delays (more than 1 year) in undergoing screening were observed in approximately 25% of the cases. The number of perceived barriers to screening (eg, discomfort, embarrassment) was the only variable related significantly to noncompliance/screening delay (odds ratio, 1.2; 95% confidence interval, 1.1-1.3). Use of sedatives during the procedure and receipt of a reminder letter seemed to facilitate better compliance. CONCLUSIONS: Although few high-risk individuals abstain from screening entirely, approximately one in 4 deviates significantly from the recommended frequency of screening. Increased compliance may be achieved by reducing the discomfort and embarrassment associated with the procedure and by the use of reminder letters.     

The effects of L-748706, a selective cyclooxygenase-2 inhibitor, on N-nitrosomethylbenzylamine-induced rat esophageal tumorigenesis

Epidemiological studies suggest that the frequent intake of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a decreased risk of developing esophageal squamous cell carcinoma (SCC). This decrease is thought to correlate with the inhibition of cyclooxygenase (COX) activity. The production of prostaglandin E2 (PGE2), a major metabolite of COX, is increased in numerous human cancers including esophageal SCC, therefore, inhibition of COX activity and subsequent suppression of the formation of PGE2 may be chemopreventive in the esophagus. The objective of the present study was to determine whether L-748706 (L-706), a novel selective COX-2 inhibitor, would prevent N-nitrosomethylbenzylamine (NMBA)-induced esophageal tumor progression in the Fischer 344 (F344) rat. In rats pretreated with a low-dose of NMBA (0.25 mg/kg body weight), L-706 at 100 p.p.m. in the diet significantly reduced tumor multiplicity but not tumor incidence. At 150 p.p.m. in the diet, L-706 alone and in combination with 200 p.p.m. piroxicam produced significant reductions in both tumor incidence and multiplicity. Inhibition of tumor development in low-dose NMBA-treated rats was associated with reductions in esophageal cell proliferation rates and PGE2 levels in preneoplastic tissues. In contrast, in rats treated with a higher dose of NMBA (0.5 mg/kg body weight), neither L-706 alone nor in combination with piroxicam reduced esophageal tumor incidence or multiplicity in spite of the fact that they reduced esophageal PGE2 levels in preneoplastic tissues and in papillomas. Cell proliferation rates were reduced only in animals treated with L-706 + piroxicam. Our data suggest that the chemopreventive treatments were effective in inhibiting tumor development in NMBA-treated animals only when they reduced PGE2 levels in preneoplastic esophageal tissues approximately to those levels found in normal esophagus.     

Synthesis of 3-aryl-5-decapentyl-1,2,4-oxadiazoles possessing antiinflammatory and antitumor properties

A simple, convenient and straightforward synthesis of 3-aryl-1,2,4-oxadiazoles 4a-f from arylamidoximes 1a-f and palmitic acid 2 is described. Compounds 4a-f are non-lethal in mice at four times the therapeutic dose (i.p., LD50>1 g kg(-1) of the animals' body weight). These heterocycles have been found to possess antiinflammatory property similar to aspirin and ibuprofen. Three compounds, viz., 4a, d, e have also been evaluated for antitumor activity, where 4d exhibited an excellent activity comparable to lapachol.