Preparation and evaluation of cytotoxic potential of paclitaxel containing poly-3-hydroxybutyrate-co-3-hydroxyvalarate (PTX/PHBV) nanoparticles

Paclitaxel (PTX) is a potent anticancer drug. In the present study, PTX was loaded in poly-3-hydroxybutyrate-co-3-hydroxyvalarate (PHBV) to fabricate the PTX/PHBV (drug-loaded) nanoparticles via the nanoprecipitation method. Blank PHBV nanoparticles were also prepared. The drug-encapsulation efficiency of PTX/PHBV nanoparticles was 45±0.4%. The PTX/PHBV nanoparticles exhibited a pH-sensitive release profile and followed a quasi-Fickian diffusion mechanism. Cytotoxic properties of PHBV and PTX/PHBV nanoparticles were checked against the MCF-7 and Caco-2 cell lines. The PHBV nanoparticle did not inhibit the proliferation of MCF-7 and Caco-2 cell lines, thus depicting their non-toxic and biocompatible nature. On the other hand, the PTX/PHBV nanoparticles demonstrated 1.03-fold higher cytotoxicity and 1.61-fold enhanced apoptosis after treatment with the PTX/PHBV nanoparticles versus free PTX. In summary, the PHBV nanoparticles could be a potential candidate for the delivery of PTX for cancer treatment.

A Novel Application of Deep Learning (Convolutional Neural Network) for Traumatic Spinal Cord Injury Classification Using Automatically Learned Features of EMG Signal

In this study, a traumatic spinal cord injury (TSCI) classification system is proposed using a convolutional neural network (CNN) technique with automatically learned features from electromyography (EMG) signals for a non-human primate (NHP) model. A comparison between the proposed classification system and a classical classification method (k-nearest neighbors, kNN) is also presented. Developing such an NHP model with a suitable assessment tool (i.e., classifier) is a crucial step in detecting the effect of TSCI using EMG, which is expected to be essential in the evaluation of the efficacy of new TSCI treatments. Intramuscular EMG data were collected from an agonist/antagonist tail muscle pair for the pre- and post-spinal cord lesion from five Macaca fasicularis monkeys. The proposed classifier is based on a CNN using filtered segmented EMG signals from the pre- and post-lesion periods as inputs, while the kNN is designed using four hand-crafted EMG features. The results suggest that the CNN provides a promising classification technique for TSCI, compared to conventional machine learning classification. The kNN with hand-crafted EMG features classified the pre- and post-lesion EMG data with an F-measure of 89.7% and 92.7% for the left- and right-side muscles, respectively, while the CNN with the EMG segments classified the data with an F-measure of 89.8% and 96.9% for the left- and right-side muscles, respectively. Finally, the proposed deep learning classification model (CNN), with its learning ability of high-level features using EMG segments as inputs, shows high potential and promising results for use as a TSCI classification system. Future studies can confirm this finding by considering more subjects.

Comparison study of classification methods of intramuscular electromyography data for non-human primate model of traumatic spinal cord injury

Traumatic spinal cord injury is a serious neurological disorder. Patients experience a plethora of symptoms that can be attributed to the nerve fiber tracts that are compromised. This includes limb weakness, sensory impairment, and truncal instability, as well as a variety of autonomic abnormalities. This article will discuss how machine learning classification can be used to characterize the initial impairment and subsequent recovery of electromyography signals in an non-human primate model of traumatic spinal cord injury. The ultimate objective is to identify potential treatments for traumatic spinal cord injury. This work focuses specifically on finding a suitable classifier that differentiates between two distinct experimental stages (pre-and post-lesion) using electromyography signals. Eight time-domain features were extracted from the collected electromyography data. To overcome the imbalanced dataset issue, synthetic minority oversampling technique was applied. Different ML classification techniques were applied including multilayer perceptron, support vector machine, K-nearest neighbors, and radial basis function network; then their performances were compared. A confusion matrix and five other statistical metrics (sensitivity, specificity, precision, accuracy, and F-measure) were used to evaluate the performance of the generated classifiers. The results showed that the best classifier for the left- and right-side data is the multilayer perceptron with a total F-measure of 79.5% and 86.0% for the left and right sides, respectively. This work will help to build a reliable classifier that can differentiate between these two phases by utilizing some extracted time-domain electromyography features.

Incidence of nasopalatine canal perforation in relation to virtual implant placement: A cone beam computed tomography study

BACKGROUND

The nasopalatine canal (NPC) is of special importance when considering implant therapy in the maxillary central incisors' region.

PURPOSE

To investigate the incidence of NPC perforation in relation to virtual immediate implant placement.

MATERIALS AND METHODS

A search through the cone beam computed tomography (CBCT) database of The University of Oklahoma-College of Dentistry was conducted. First, canal related measurements were conducted. Second, digital prosthetic planning was performed. Then, immediate implants were virtually placed and additional measurements were performed. Perforation rate was assessed. Last, data obtained was statistically analyzed.

RESULTS

A total of 217 scans fulfilled the inclusion criteria. Only 8% of cases showed NPC perforation. The perforation occurred at mid-third of the implant or at the mid and apical third in 33% and 22% of the cases, respectively. A statistically significant association was found between perforation of NPC and bone width palatal to the root of the central incisor (P < .0001) as well as canal angulation (P = .0196). NPC angulation (°) and palatal bone width (mm) predisposed to a higher risk of perforation. Only 27.78% of the perforations could be overcome by the installation of shorter implants.

CONCLUSIONS

Low incidence of NPC perforation could be expected when immediately placing implants in the maxillary incisor region.

Neurophysiological Characterization of a Non-Human Primate Model of Traumatic Spinal Cord Injury Utilizing Fine-Wire EMG Electrodes

This study aims to characterize traumatic spinal cord injury (TSCI) neurophysiologically using an intramuscular fine-wire electromyography (EMG) electrode pair. EMG data were collected from an agonist-antagonist pair of tail muscles of Macaca fasicularis, pre- and post-lesion, and for a treatment and control group. The EMG signals were decomposed into multi-resolution subsets using wavelet transforms (WT), then the relative power (RP) was calculated for each individual reconstructed EMG sub-band. Linear mixed models were developed to test three hypotheses: (i) asymmetrical volitional activity of left and right side tail muscles (ii) the effect of the experimental TSCI on the frequency content of the EMG signal, (iii) and the effect of an experimental treatment. The results from the electrode pair data suggested that there is asymmetry in the EMG response of the left and right side muscles (p-value < 0.001). This is consistent with the construct of limb dominance. The results also suggest that the lesion resulted in clear changes in the EMG frequency distribution in the post-lesion period with a significant increment in the low-frequency sub-bands (D4, D6, and A6) of the left and right side, also a significant reduction in the high-frequency sub-bands (D1 and D2) of the right side (p-value < 0.001). The preliminary results suggest that using the RP of the EMG data, the fine-wire intramuscular EMG electrode pair are a suitable method of monitoring and measuring treatment effects of experimental treatments for spinal cord injury (SCI).

Model of Traumatic Spinal Cord Injury for Evaluating Pharmacologic Treatments in Cynomolgus Macaques (Macaca fasicularis)

Here we present the results of experiments involving cynomolgus macaques, in which a model of traumatic spinal cord injury (TSCI) was created by using a balloon catheter inserted into the epidural space. Prior to the creation of the lesion, we inserted an EMG recording device to facilitate measurement of tail movement and muscle activity before and after TSCI. This model is unique in that the impairment is limited to the tail: the subjects do not experience limb weakness, bladder impairment, or bowel dysfunction. In addition, 4 of the 6 subjects received a combination treatment comprising thyrotropin releasing hormone, selenium, and vitamin E after induction of experimental TSCI. The subjects tolerated the implantation of the recording device and did not experience adverse effects due the medications administered. The EMG data were transformed into a metric of volitional tail moment, which appeared to be valid measure of initial impairment and subsequent natural or treatment-related recovery. The histopathologic assessment demonstrated widespread axon loss at the site of injury and areas cephalad and caudad. Histopathology revealed evidence of continuing inflammation, with macrophage activation. The EMG data did not demonstrate evidence of a statistically significant treatment effect.

Alterations in Tooth Structure and Associated Systemic Conditions

A variety of factors can affect the normal development of tissues and may lead to variation in the normal compliment of teeth and development of alterations in the shape and size of teeth. These anomalies can be congenital, developmental, or acquired. Dental anomalies can present as isolated traits or be associated with systemic conditions and syndromes for which early diagnosis and genetic testing may result in better treatment outcomes and quality of life. Dentists play an essential role in the multidisciplinary management of these abnormalities. This article discusses some of these tooth alterations and associated systemic and genetic conditions.

Comparison of Healing Following Tooth Extraction With Ridge Preservation Using Anorganic Bovine Bone Mineral Particulate and Self-Expanding Composite Graft

OBJECTIVES

To study the radiographic mean grey values after bone grafting and to clinically evaluate the intraoral alveolar ridge dimensional stability with anorganic bovine bone mineral (ABBM) particulate and a patented self-expanding composite graft (SECG) after 6 months of healing.

METHODS

A total of 20 single-rooted tooth-extraction sites grafted with either ABBM or SECG were evaluated radiographically and clinically after 6 months of healing, prior to dental implant placement. A multivariable mixed regression model was used.

RESULTS

Mean grey values at the coronal, midroot, and apex levels within the socket were compared. A significant difference was shown in the midroot and apex maxillary regions. For both of these regions, the estimated mean grey value of ABBM was significantly lower than that of SECG. No significant difference was noted in the ridge-width change patterns between the two materials.

CONCLUSION

This study supports that suggestion that newer SECG is as efficacious in terms of mean grey value and alveolar ridge stability as the previously available ABBM.

Xpert(®) MTB/RIF under routine conditions in diagnosing pulmonary tuberculosis: a study in two hospitals in Pakistan

Xpert(®) MTB/RIF testing was offered to consecutive patients with presumptive tuberculosis (TB) attending two hospitals in Pakistan during April-May 2012, in addition to routine diagnostic protocol (smear microscopy, chest radiography and clinical judgement). We assessed the relative contribution of each tool in detecting pulmonary TB under routine conditions. Of 606 participants, 121 (20%) were detected as pulmonary TB: 46 (38%) by microscopy, 38 (31%) by Xpert alone and 37 (31%) on clinical and radiological grounds; 41 (65%) were detected by both Xpert and microscopy. One patient had rifampicin resistance. Although Xpert detected approximately twice as many TB cases as microscopy (n = 79, 65%), clinical judgement remained favoured by clinicians even when smear and Xpert were negative.

Biological therapy and dentistry: a review paper

In recent years, a new class of drugs has revolutionized the treatment of autoimmune, allergic, infectious, and many more diseases. This new class of drugs is made of 3 groups-cytokines, monoclonal antibodies, and fusion proteins-that may target special damaged cells but not all the cells. These drugs may have side effects such as infection, hypersensitivity, hematologic disorders, cancer, hepatotoxicity, and neurologic disorders. However, there is not enough evidence or long-term studies of the mechanism of action and side effects of these drugs. Patients receiving biological therapies may need special consideration in dentistry. This paper is a review of the classification, mechanism of action, and side effects of these drugs and dental consideration for patients receiving biological therapies.

Case report of an oral fibroma occurring in a patient with familial multiple lipomas

A wide variety of lesions may manifest in the oral soft tissues that could be confusing and challenging for the clinicians. These lesions could be as simple as trauma-induced ulcers that need about 2 weeks to heal, to a more complicated situation such as oral cancer. The key points in developing diagnosis and a possible treatment plan may include a comprehensive oral examination, simple understanding of normal oral tissue features, and knowledge of common oral lesions. This will help in the development of a differential diagnosis of the oral lesions/masses based on the risk factors in that particular patient. In this case report, we present a simple oral mass in a patient who had an oral fibroma and lipomas in other areas.

Antibiotic prophylaxis: a literature review

Antibiotic prophylaxis has been a matter of great interest and has been discussed by researchers and clinicians over the years. Changes and recommendations have been made in order to clarify protocol and make it safer for patients. Various organizations such as the American Heart Association, American Academy of Oral Surgeons, American Dental Association, and American Academy of Oral Medicine have played vital roles in formulating guidelines for antibiotic prophylaxis. These recommendations for prevention of infective endocarditis have been based on clinical experiences and research as well as expert opinion. This paper summarizes the most recent guidelines for general readers so that informed decisions may be made that are in the interest of patients and practitioners.

Study of the inferior alveolar canal and mental foramen on digital panoramic images

OBJECTIVES

To study the radiographic location of the mental foramen and appearance of the inferior alveolar canal and the relationship between image gray values and the clarity of inferior alveolar canal on the digital panoramic images and to evaluate if the histogram equalization of the digital image would improve the visualization of the inferior alveolar canal outline on the digital panoramic images in the mandible.

METHODS

Five hundred digital panoramic images were evaluated by two examiners using a specific inclusion criteria. Only the right side of the mandible was studied. Chi-square analyses were used for comparisons of distributions. Mean and median pixel values were analyzed separately with a one-way analysis of variance. Also, percentages were calculated to report the usefulness of the histogram equalization for visualization of canal.

RESULTS

RESULTS show variation in location of mental foramen. Most frequent location of the mental foramen was reported as first and second premolar region. Chi-square analysis showed that the frequency of occurrence of the mental foramen was equally probable for any of the three locations. The study did not find significant usefulness of the gray values obtained from the histogram equalization in predicting the clarity of inferior alveolar canal outlines.

CLINICAL SIGNIFICANCE

Knowing the normal relationship and the anatomical variation of the maxillofacial structures for each patient is important for surgical implant treatment planning to avoid future complications. It is also important to be familiar with the advantages and limitations of diagnostic aids available before making treatment planning decisions based on such findings.

KEYWORDS

Digital imaging, Panoramic, Inferior alveolar canal, Mental foramen. How to cite this article: Pria CM, Masood F, Beckerley JM, Carson RE. Study of the Inferior Alveolar Canal and Mental Foramen on Digital Panoramic Images. J Contemp Dent Pract 2011;12(4):265-271. Source of support: Nil Conflict of interest: None declared.

A comparison of panoramic image quality between a digital radiography storage phosphor system and a film-based system

AIM

To compare digital panoramic images acquired for the presurgical assessment of third molars captured with a storage phosphor-based system with conventional film panoramic radiographs.

METHODS AND MATERIALS

A total of 51 pairs of digital and conventional panoramic images, made simultaneously, were included in this study. The images were evaluated for diagnostic quality prior to third molar surgery by two experienced oral surgeons and rated with a four-point grading scale.

RESULTS

Despite the fact that conventional panoramic images were rated higher than the digital images, the difference was not statistically significant.

CONCLUSIONS

Conventional and digital panoramic images were found to be of comparable image quality with regard to their diagnostic contribution to third molar surgery.

CLINICAL SIGNIFICANCE

This study is contributory to understanding differences in image quality between digital and conventional panoramic radiography for certain diagnostic tasks. The lack of significant differences in image quality may be an endorsement for digital panoramic radiography.

Presence of carotid artery calcification on panoramic radiographs of patients with chronic diseases

This study sought to investigate carotid artery calcification (CAC) on panoramic radiographs from both healthy patients and those patients suffering from different chronic diseases. A total of 247 patients met the inclusion criteria and were reviewed. Ninety-two patients had one or more chronic diseases as indicated by their records; the remaining 155 patients had no mention of a chronic disease and were considered to be healthy controls. Among all patients, 13% had evidence of CAC, 21% of the patients with one or more chronic diseases had CAC, and only 8% of the patients in the control group had CAC. Those with liver disease only had the highest proportion (33%) of CAC.

Bisphosphonates, osteonecrosis of the jaw, and dental treatment recommendations

Millions of patients in the United States take bisphosphonates for management of malignant bone metastases, osteoporosis, osteitis deformans (Paget's disease), and osteogenesis imperfecta. Since 2003, over 200 cases of osteonecrosis of the jaws have been described, mostly in patients with multiple myeloma or breast cancer patients, and to a lesser extent in patients on oral medications.

Findings from panoramic radiographs of the edentulous population and review of the literature

OBJECTIVE

The purpose of this study was to evaluate the frequency of positive radiographic findings in panoramic radiographs of edentulous arches.

METHOD

A sample of 327 panoramic radiographs was selected from the patient pool at the University of Oklahoma College of Dentistry. Radiographs were evaluated for presence of retained root tips, impacted teeth, radiolucent and radiopaque areas, soft tissue calcifications, and foreign bodies.

RESULTS

Approximately 57.5% of panoramic radiographs revealed no positive radio-graphic findings, while the remaining 42.5% contained 1 or more positive radiographic findings. Thirty-nine root fragments were identified, and the majority were located in the maxilla. However, only 5 pathological findings (3.8%) required treatment modification before denture fabrication.

CONCLUSIONS

Results of the study do not support routine pretreatment panoramic radiography on patients seeking denture fabrication. Panoramic radiography is a valuable diagnostic tool in the pretreatment assessment of partially and completely edentulous patients, but their routine use in such patients should be discouraged.

Comparison of panoramic radiography and panoramic digital subtraction radiography in the detection of simulated osteophytic lesions of the mandibular condyle

OBJECTIVE

The aim of this study was to compare panoramic temporomandibular joint radiography, unenhanced and color-enhanced digital-subtraction radiography with respect to detectability of simulated osteophytic lesions of the mandibular condyle.

METHODS

Three dry human skulls with no obvious temporomandibular joint pathology were selected. Four sizes of bone chips were placed on the anterior aspect of the condyle at medial, central, and lateral locations. Panoramic radiographs were made with and without the chips in place. These paired radiographs were digitized, and unenhanced and color-enhanced digital-subtraction images of the original panoramic images were obtained. Eight observers evaluated 72 randomized images of each modality for the presence or absence of simulated osteophytic lesions of the mandibular condyle, grading the images on a 100-point scale.

RESULTS

A(z) values for overall diagnostic accuracy of the three imaging modalities were 0.5376 for panoramic radiography, 0.7861 for unenhanced digital subtraction radiography, and 0.7923 for color-enhanced digital-subtraction radiography. Digital-subtraction radiography improved the detection accuracy of the original panoramic films.

CONCLUSION

Panoramic radiographs were significantly less accurate in the detection of simulated osteophytic lesions of the mandibular condyle than the two digital-subtraction techniques.

An immunohistochemical study of neurotransmitter profiles in developing human visual cortex

The temporal pattern of development and distribution of gamma aminobutyric acid, serotonin, substance P and neuropeptide Y immunoreactive profiles was studied in the human visual cortex from 16 to 26 weeks of gestation, using an immunohistochemical technique. The immunoreactive profiles showed an increase in number and a change in their morphology and distribution pattern over the time period studied. A large number of neurons, fibers and terminals were stained with GABA antibody at 17-18 weeks and were distributed throughout the five zones of the developing visual cortex. GABA neurons were non-pyramidal and bipolar in form at 17-18 weeks while at 18-19 and 20-21 weeks the cells of subplate and intermediate zones were multipolar. Substance P and serotonin immunopositive fibers were present mainly in the intermediate zone at 16 and 17-18 weeks, where they were oriented in a horizontal manner. At subsequent ages they invaded the other zones also. Substance P positive neurons could be visualized only at 26 weeks of gestation in the intermediate, subventricular and ventricular zones; no cell bodies, however, stained with serotonin antibody. Neuropeptide Y immunoreactive cells and fibers were first seen in the intermediate zone but later were found to be distributed in other zones too. The observations indicate that the intermediate zone of the visual cortex in which the transmitters and peptides appear earlier assumes importance in the normal development as also noted in other mammals.

Early development of visual cortex in human fetuses

Prenatal development of visual cortex (area 17) was studied in human fetuses of 8-9, 13-15 and 16-18 weeks of gestation, with a view to analyse the early critical events. Under light microscope, five zones of development were seen in all the age groups. The total thickness of cortex of area 17 as well as that of its cortical plate was measured with the help of camera lucida. It was observed that the total thickness of the cortex increased with increase in age. Diversity in the shape, size, staining intensity and arrangement of neurons was noted in the different zones. Most of the cells were found to have a thin rim of cytoplasm and a prominent nucleus with multiple nucleoli. The cells in subventricular zone and cortical plate were regularly arranged in vertical rows while in other zones, they were irregularly scattered. Several mitotic figures were seen in the ventricular zone at 8-9 weeks but later they were also noticed in subventricular and intermediate zones. In the later ages the mitotic figures were observed to be fewer in the ventricular zone. No mitosis was seen in cortical plate at any age period.