Survey of NAACLS accredited histotechnology programs in the United States.

Histotechnology educational programs are accredited by the National Accrediting Agency for Clinical Laboratory Sciences (NAACLS) and currently number fewer than 50 in the United States which contributes to the shortages of laboratory personnel. A survey tool designed with REDCap software was distributed to all programs identified on the NAACLS website and consisted of three parts: a) program information, b) facility information, and c) challenges. Programs are located primarily in large urban centers where populations are most concentrated. The median class size was 6 which may explain the excellent student outcomes to include 96% graduation rates and 90.7% board of registry examination pass rates. Overall, programs had ample equipment, funding, and administrative support. Costs to attend the programs were relatively low (<$3,000 per semester) for over half of the programs. However, due to the small number of accredited education programs across the US, potential students do not often have access to an institution in their area. The programs indicated that the most common challenge was recruitment of adequate high-quality candidates which may explain, in part, the persistent shortage of personnel in the histology laboratory.

The effect of overexpression of Lrp5 on orthodontic tooth movement.

OBJECTIVE: To analyse the effect of gain-of-function mutations in the low-density lipoprotein receptor-related protein 5 (Lrp5) on orthodontic tooth movement (OTM). SETTING AND SAMPLE POPULATION: A split-mouth study design was utilized. Thirty-two male Lrp5-high bone mass (HBM) knock-in mice including A214V and G171V mutants (n = 16/group) and sixteen C57BL/6 wild-type (WT) mice were included in the study. MATERIALS AND METHODS: A mouse model of OTM was used for mesial movement of the maxillary first molar using a closed-coil nickel titanium (NiTi) spring attached between the molar and the incisors. After 21 days, the dissected maxillae were scanned for micro-computed tomography (micro-CT) analyses and embedded in methyl methacrylate and paraffin for histological staining and imaging. Histological analyses included immunohistochemistry for sclerostin (Sost), tartrate-resistant acid phosphatase (TRAP) staining for osteoclasts and fluorescent imaging. RESULTS: OTM in the A214V and G171V groups was significantly less than the WT group. Bone volume (BV), per cent bone volume (BV/TV) and trabecular thickness (Tb.Th) were significantly increased in both A241V and G171V animals compared to the WT animals. On the compression side, decreased osteoclast activity was seen in both A214V and G171V groups compared to the WT group. Fluorescent labelling demonstrated that the pattern of bone deposition in the A214V animals was periosteal whereas the G171V animals added bone endocortically. CONCLUSION: Gain-of-function mutations of Lrp5 decrease orthodontic tooth movement by increasing alveolar bone mass and reducing osteoclast-mediated bone resorption.

The Effect of Overexpression of Lrp5 on the Temporomandibular Joint.

OBJECTIVE: The temporomandibular joint (TMJ) is a unique fibrocartilaginous joint that adapts to mechanical loading through cell signaling pathways such as the Wnt pathway. Increased expression of low-density lipoprotein receptor-related protein 5 (Lrp5), a co-receptor of the Wnt pathway, is associated with a high bone mass (HBM) phenotype. The objective of this study was to analyze the effect of overexpression of Lrp5 on the subchondral bone and cartilage of the TMJ in mice exhibiting the HBM phenotype. DESIGN: Sixteen-week-old Lrp5 knock-in transgenic mice carrying either the A214V (EXP-A) or G171V (EXP-G) missense mutations, and wildtype controls (CTRL) were included in this study. Fluorescent bone labels, calcein, alizarin complexone, and demeclocycline were injected at 3.5, 7.5, and 11.5 weeks of age, respectively. The left mandibular condyle was used to compare the subchondral bone micro-computed tomography parameters and the right TMJ was used for histological analyses. Cartilage thickness, matrix proteoglycan accumulation, and immunohistochemical localization of Lrp5 and sclerostin were compared between the groups. RESULTS: Subchondral bone volume (BV) and percent bone volume (BV/TV) were significantly increased in both EXP-A and EXP-G compared with CTRL (P < 0.05) whereas trabecular spacing (Tb.Sp) was decreased. Cartilage thickness, extracellular matrix production, and expression of Lrp5 and Sost were all increased in the experimental groups. The separation between the fluorescent bone labels indicated increased endochondral maturation between 3.5 and 7.5 weeks. CONCLUSIONS: These data demonstrate that Lrp5 overexpression leads to adaptation changes in the mandibular condylar cartilage of the TMJ to prevent cartilage degradation.

Osteoblast differentiation during orthodontic tooth movement.

OBJECTIVES: To analyse the expression of osteoblast differentiation markers and osteoclast activity in the periodontal ligament (PDL) following 2, 4 and 7 days of orthodontic tooth movement (OTM) in an animal model. SETTING AND SAMPLE POPULATION: Eighteen C57BL/6 wild-type mice. MATERIAL AND METHODS: For the OTM model, orthodontic force was applied to the maxillary right first molar using a closed-coil NiTi spring activated between the molar and incisors. The left side served as the control. Following OTM, the dissected tissues were scanned for micro-computed tomography (micro-CT) analysis and processed for histology. Histological stains included tartrate-resistant acid phosphatase (TRAP) staining for osteoclasts and immunohistochemistry for osteoblast markers alpha-smooth muscle actin (α-SMA), osteopontin (OP) and osteocalcin (OC). RESULTS: Micro-CT analysis showed increasing OTM on days 2, 4 and 7 days as well as decrease in bone volume and per cent bone volume at 4 and 7 days. Statistically significant increases in osteoblast marker expression were seen in all groups when compared to the control. TRAP expression was highest at 4 and 7 days, α-SMA was highest at 2 days and OP/OC was highest at 4 days. CONCLUSION: During OTM, proliferation of pre-osteoblasts peaks at 2 days while mineralization of the osteoid peaks at 4 days. The osteoclast response is delayed.

Maxillary expansion in an animal model with light, continuous force.

OBJECTIVES: Maxillary constriction is routinely addressed with rapid maxillary expansion (RME). However, the heavy forces delivered by most RME appliances to expand the palate may lead to deleterious effects on the teeth and supporting tissues. The objective of this study was to explore a more physiologic maxillary expansion with light continuous force. MATERIALS AND METHODS: Twenty 6-week-old Sprague-Dawley rats were equally divided into experimental (EXPT) and control (CTRL) groups. A custom-fabricated archwire expansion appliance made from 0.014-inch copper-nickel-titanium wire was activated 5 mm and bonded to the maxillary molar segments of animals in the EXPT group for 21 days. The force applied to each maxillary segment was 5 cN. Microfocus x-ray computed tomography and histological analyses were used to compare the tooth movement and bone morphology in the midpalatal suture and buccal aspect of the alveolar process between the EXPT and CTRL groups. Descriptive statistics (mean ± standard error of the mean) and nonparametric statistical tests were used to compare the outcomes across groups. RESULTS: Compared to the CTRL group, there was a statistically significant increase in buccal tooth movement and expansion of the midpalatal suture in the EXPT group. There was no difference in the bone morphologic parameters between groups. The mineral apposition rate was increased on the buccal surface of the alveolar process in the EXPT group. CONCLUSIONS: Application of light, continuous force resulted in maxillary osseous expansion due to bilateral sutural apposition and buccal drift of the alveolar processes. This animal experiment provides a more physiologic basis for maxillary expansion.

A Randomized Split-Mouth Clinical Trial on Effectiveness of Amnion-Chorion Membranes in Alveolar Ridge Preservation: A Clinical, Radiologic, and Morphometric Study.

PURPOSE: Recent case reports suggest that amnion-chorion membranes (ACM) and dense polytetrafluoroethylene membranes (dPTFE) can be left exposed during ridge preservation. The aim of this study was to compare the effectiveness of these membranes in ridge preservation, particularly when they are intentionally left exposed. MATERIALS AND METHODS: A split-mouth, single-blind, randomized trial design was used to compare treatments with the two membranes in 22 nonmolar sites on the same arch. Ridge dimensions were recorded clinically and with cone beam computed tomography prior to and 3 months after ridge preservation. Postoperative discomfort was recorded with Visual Analog Scale (VAS) forms. Mixed­model analysis of variance was used to test significance. RESULTS: Clinical and radiographic ridge dimensions were not significantly different between the two treatments. ACM sites had significantly more osteoid and higher bone volume density but significantly less graft particles and bone surface density compared with dPTFE. Mineralized bone area and soft tissue area were not significantly different between the two treatments. ACM sites had significantly lower postoperative VAS scores compared with dPTFE. CONCLUSION: Intentionally exposed ACM is equally effective in ridge preservation compared with dPTFE. Additionally, ACM use may aid in reducing postoperative VAS scores, and potentially result in better quality of bone available for implant placement, as evidenced by improved histomorphometric measures.

Gamma-tocopherol attenuates moderate but not severe colitis and suppresses moderate colitis-promoted colon tumorigenesis in mice.

Inflammation can promote colon cancer. Mechanistic studies indicate that γ-tocopherol (γT), a major form of vitamin E in diets, has anti-inflammatory and anticancer properties. Here we investigated the effectiveness of γT and a mixture of tocopherols against colitis and colitis-promoted colon tumorigenesis in male BALB/c mice. γT or mixed tocopherols (at 0.1% diet) did not show any effect on colon tumorigenesis induced by azoxymethane (AOM, 10mg/kg) with three cycles of dextran sodium sulfate (DSS at 1.5-2.5%). γT failed to exhibit protection of severe colitis caused by three cycles of DSS at 2.5%. In contrast, when AOM-initiated carcinogenesis was promoted by relatively mild colitis induced by one-cycle DSS (1.5%), γT, but not mixed tocopherols, suppressed total multiplicity of macroscopic adenomas (P=0.06) and large adenomatous polyps (>2mm(2), P<0.05) by 60 and 85%, respectively. γT also significantly decreased tumor multiplicity (>2mm(2)) induced by AOM with two cycles of 1.5% DSS even when dietary supplementation was started after AOM injection. Consistently, γT but not mixed tocopherols attenuated DSS (1.5%)-induced colon inflammation and damage as well as formation of atypical glandular hyperplasia. Mice supplemented with tocopherols had high fecal excretion of 13'-carboxychromanol, a long-chain vitamin E metabolite shown to have potent anti-inflammatory activities. Our study demonstrates that γT is able to alleviate moderate but not severe colitis and its promoted tumorigenesis, and indicates that inflammation severity should be considered in evaluating anticancer effectiveness of chemoprevention agents.