Predictors of variation in mandibular incisor enamel thickness

BACKGROUND: Interproximal reduction of mandibular incisor enamel often is performed as an adjunct to orthodontic alignment. The authors conducted a study to determine factors contributing to variations in incisor enamel thickness. METHODS: The authors compared enamel thickness between mandibular central and lateral incisors, between mesial and distal surfaces, between male and female subjects (N=40 each) and between African-American and white subjects (N=40 each). The authors also evaluated correlations between overall tooth width and enamel thickness. RESULTS: The authors found significantly greater enamel thickness in lateral incisors, on distal tooth surfaces and in black subjects (P<.0001 for each); they found no differences between male and female subjects. They found that wider teeth were associated with greater enamel thickness (P<.01) but that the amount of thickness varied greatly among subjects (range: 0.44-1.28 millimeters). CONCLUSIONS: Thicker enamel was found on the distal aspect of lateral incisors, in black subjects and in wider teeth. The authors observed, however, that the variations in thickness are not fully explained by these factors alone. CLINICAL IMPLICATIONS: If substantial enamel reduction is planned as part of dental treatment, the authors recommend that clinicians use calibrated radiographs to measure the thickness of their patients' enamel surfaces because of the extensive variation in enamel thickness among and within people.     

Evaluation of fundus autofluorescence patterns in age-related macular degeneration

AIM: To study the various morphological patterns of fundus autofluorescence (FAF) images in patients with age-related macular degeneration (AMD) in Indian population. METHODS: Totally 179 eyes of 104 patients with clinical diagnosis of AMD were recruited into the study. Autofluorescence images were captured using confocal scanning laser ophthalmoscope and the patterns of FAF were classified. RESULTS: Of 179 eyes, 27 (15.08%) were early AMD, 58 (32.41%) were intermediate AMD, 94 eyes (52.51%) were late AMD. Of 94 eyes with late AMD, 79 (84.04%) were neovascular AMD and 15 (15.96%) were central geographic atrophy. In eyes with early and intermediate AMD, 9 patterns of FAF were noted. Six patterns (normal, minimal change, focal increased, patchy increased, linear, reticular) were similar to that in the published classification. Two patterns (lacelike and speckled) described in the published classification were not found. Three new patterns (focal hypo-fluorescence, patchy hypo-fluorescence, mixed focal hypo-fluorescence and hyper-fluorescence) were detected. In eyes with neovascular AMD, 6 morphological patterns of FAF were noted. Two patterns (mixed hypo-fluorescence and hyper-fluorescence, central hypo-fluorescence with hyper-fluorescent rim) were similar to that in published classification. Two patterns (normal, near normal or normal background fluorescence in the centre of hypo-fluorescent area) described in the published classification were not found. Four new patterns (minimal change, hypo-fluorescent patch, central hypo-fluorescence with surrounding reticular, bull’s eye) were recognized. In eye with central geographic atrophy 5 morphological patterns were noted and these were similar to that in published classification. CONCLUSION: Phenotypic differences in the pattern of FAF exist in the study population compared to existing classification systems.     

Conjunctivodacryocystorhinostomy using a high-density porous polyethylene-coated tear drain tube

To evaluate the outcome of conjunctivodacryocystorhinostomy using a high-density porous polyethylene (HDPP)-coated tear drain tube. Patients with epiphora due to a proximal lacrimal system block were included in a prospective interventional case study. A total of 22 eyes were treated with lacrimal bypass surgery using the HDPP-coated tube. On follow-up (12–41 months), 21 eyes had a patent well-positioned tube with subjective relief of epiphora. In one eye, a loose sleeve was noted during surgery. The tube dislodged postoperatively and was removed. A high success rate with only a few minor complications is achievable using a HDPP-coated tear drain tube for lacrimal bypass surgery. Long-term follow-up is required to look for tube blockage due to conjunctival or nasal mucosal overgrowth.     

Extracorporeal treatment of cast nephropathy

Acute kidney injury (AKI) is common in patients with multiple myeloma (MM), most commonly caused by cast nephropathy resulting from precipitation of free light chains (FLC) in renal tubules. AKI may be irreversible and require dialysis and predicts a poor prognosis. Reduction in serum FLC concentration is thought to be associated with improved likelihood of kidney function recovery in MM patients with AKI. Plasma exchange (PE), by removing circulating FLC, has been used as a treatment modality to improve kidney function in MM, although its efficacy remains uncertain. Extracorporeal treatment with extended high cutoff hemodialysis (HCO-HD) has also recently been studied as a potentially more effective means of FLC removal. Both PE and HCO-HD may be beneficial in some patients, but only when used as adjuncts to successful chemotherapy. Further research is necessary to establish the specific efficacy of each of these extracorporeal methods in the treatment of cast nephropathy.     

Sorafenib enhances the antitumor effects of chemoradiation treatment by downregulating ERCC-1 and XRCC-1 DNA repair proteins

Head and neck squamous cell carcinoma remains a challenging clinical problem because of the persisting high rate of local and distant failure due to the acquisition of chemo- and radioresistance. In this study, we examined if treatment with sorafenib, a potent inhibitor of Raf kinase and VEGF receptor, could reverse the resistant phenotype in tumor and tumor-associated endothelial cells, thereby enhancing the therapeutic efficacy of currently used chemoradiation treatment. We used both in vitro and in vivo models to test the efficacy of sorafenib either as a single agent or in combination with chemoradiation. Sorafenib, as a single agent, showed antitumor and angiogenesis properties, but the effects were more pronounced when used in combination with chemoradiation treatment. Sorafenib significantly enhanced the antiproliferative effects of chemoradiation treatment by downregulating DNA repair proteins (ERCC-1 and XRCC-1) in a dose-dependent manner. In addition, combination treatment significantly inhibited tumor cell colony formation, tumor cell migration, and tumor cell invasion. Combination treatment was also very effective in inhibiting VEGF-mediated angiogenesis in vitro. In a severe combined immunodeficient mouse xenograft model, combination treatment was very well tolerated and significantly inhibited tumor growth and tumor angiogenesis. Interestingly, following combination treatment, low-dose sorafenib treatment alone was highly effective as a maintenance regimen. Taken together, our results suggest a potentially novel strategy to use sorafenib to overcome chemo- and radioresistance in tumor and tumor-associated endothelial to enhance the effectiveness of the chemoradiation therapy.