Patients' Perceptions Regarding Acceptance of Dental Implants as an Option for the Replacement of Missing Teeth: An Observational Study

INTRODUCTION

Dental implants enhance the self-assurance and overall well-being of individuals by providing oral comfort during mastication and a notable degree of contentment. The objectives of the present study were to assess patients' perception of opting or non-opting for dental implants as a replacement for missing teeth and to determine the correlation between various factors and perceived demand for dental implant treatment.

MATERIALS AND METHODS

 A cross-sectional observational study was conducted on 214 partially edentulous individuals aged between 21 and 50 years. These patients sought treatment to replace their missing teeth. The participants were provided with detailed information regarding various options for replacing their missing teeth, including removable prostheses, fixed partial dentures, and dental implants. The researchers recorded and evaluated the reasons behind the patients' decision to opt for or decline dental implant treatment using the chi-squared test. Categorical variables were summarized as percentages (n %). The association between variables and binary data was examined using point biserial correlation, whereas, for continuous data, the Pearson correlation coefficient was employed.

RESULTS

About 65 (30.4%) patients opted for dental implant treatment and 149 (69.6%) patients did not opt for dental implant treatment. Missing teeth were found in 120 women (56.08%) and 94 men (43.92%). The main reason for seeking dental implant treatment was the need for improvement in functions such as chewing in 65 (100%) patients, followed by the need for improvement in oral health in 57 (88%), aesthetics in 54 (83%), need for bone and adjacent teeth preservation in 52 (80%), and durability of dental implants in 46 (71%) patients. The main reasons for not seeking dental implant treatment and opting for fixed prostheses other than dental implants or removable prostheses cost 149 (100%), fear of surgery 132 (91%), underlying health issues 121 (81%), lack of knowledge about dental implants 120 (80.5%), and time management issues 92 (62%). Gender, age, and number of missing teeth showed a negative correlation, whereas level of education, social status, and oral health awareness showed a positive correlation with the perceived need for dental implant treatment.

CONCLUSION

Dental implant treatment was preferred by 30.4% of patients, which was influenced by gender, sex, level of education, social status, awareness of oral health, and number of missing teeth. Cost, fear of surgery, underlying medical conditions, lack of knowledge, and time management are some reasons for not opting for dental implant treatment.

Improved Fabrication of Implant Retained Auricular Prosthesis with Digital Technologies

A 28-year-old male patient came to the prosthodontics department seeking replacement for his congenital defect left ear. With the use of digital technology, a silicone implant supported bar retained auricular prosthesis that is an exact match in size, shape, and orientation to the existing contralateral ear was made.

Association Between Candida albicans and COVID-19 in Complete Denture Wearers: An Observational Study

Introduction The phenomenon of coronavirus disease 2019 (COVID-19)-related candidiasis is gaining increased attention and acknowledgment as an integral component of the severe consequences of COVID-19. The aim of the present study was to assess the association between Candida albicans and COVID-19 in complete denture wearers. Materials and methods An observational study was conducted on 45 complete denture wearers, who were divided into three groups as follows: Group 1, 15 subjects with mild to moderate COVID-19 infection; Group 2, 15 subjects with severe COVID-19 infection; and Group 3, 15 subjects without COVID-19 infection. Mean colony forming units (CFU) were observed on agar plates containing Sabouraud dextrose in the salivary samples of the participants. Analysis of variance, followed by post-hoc analysis by Tukey's test, was used to compare CFU between the groups. Pearson's correlation coefficient was used to study the correlation between variables. Results The highest average colony-forming units of Candida albicans were observed in Group 2, followed by Group 1, compared to the control group, and a significant (p<0.001) difference was found. A weak positive correlation was found between the age of the patients and the duration of denture usage, as well as between age and the counts of Candida albicans in Groups 1 and 3. This correlation was more pronounced in Group 3. A strong positive correlation was observed in all groups between the Candida albicans count and the duration of denture usage by the patients. Conclusion The association between Candida albicans and denture wear was compounded by the presence of COVID-19. Consequently, the timely identification of Candida albicans infection in patients with COVID-19 is important to establish more efficacious approaches for antifungal treatment and prophylactic interventions.

Extra-mandibular Osteoradionecrosis after the Treatment of Head and Neck Cancer

AIMS

Osteoradionecrosis (ORN) is a serious toxicity of head and neck radiotherapy. It predominantly affects the mandible. Extra-mandibular ORN is rare. The aim of this study was to report the incidence and outcomes of extra-mandibular ORNs from a large institutional database.

MATERIALS AND METHODS

In total, 2303 head and neck cancer patients were treated with radical or adjuvant radiotherapy. Of these, extra-mandibular ORN developed in 13 patients (0.5%).

RESULTS

Maxillary ORNs (n = 8) were a consequence of the treatment of various primaries (oropharynx = 3, sinonasal = 2, maxilla = 2, parotid = 1). The median interval from the end of radiotherapy to the development of ORN was 7.5 months (range 3-42 months). The median radiotherapy dose in the centre of the ORN was 48.5 Gy (range 22-66.5 Gy). Four patients (50%) healed in 7, 14, 20 and 41 months. All temporal bone ORNs (n = 5) developed after treatment to the parotid gland (of a total of 115 patients who received radiotherapy for parotid gland malignancy). The median interval from the end of radiotherapy to the development of ORN was 41 months (range 20-68 months). The median total dose in the centre of the ORN was 63.5 Gy (range 60.2-65.3 Gy). ORN healed in only one patient after 32 months of treatment with repeated debridement and topical betamethasone cream.

CONCLUSION

Extra-mandibular ORN is a rare late toxicity and this current study provides useful information on its incidence and outcome. The risk of temporal bone ORN should be considered in the treatment of parotid malignancies and patients should be counselled. More research is required to determine the optimal management of extra-mandibular ORN, particularly on the role of the PENTOCLO regimen.

Role of Adjuvant Radiotherapy in Acinic Cell Carcinoma of the Salivary Glands: A Systematic Review

A systematic review was carried out to evaluate if adjuvant radiotherapy for acinic cell carcinomas (ACCs) of salivary glands improves survival. Twelve retrospective studies published between 2000 and 2020 that analysed the effect of radiotherapy on salivary gland neoplasms and ACCs of salivary glands and met the inclusion criteria were included in the review. The overall quality of the studies was moderate to low. There was no high-quality evidence for improved survival with radiotherapy for ACCs of the salivary gland. Some evidence suggests that there may be an advantage for patients with high-grade tumours, but these data should be interpreted with caution due to the small number of patients and low-quality evidence. Good quality of evidence is lacking. Recommendation for adjuvant radiotherapy for tumours with poor prognostic factors will require discussion and shared decision-making with the patients.

A Bacteriophage Microgel Effectively Treats the Multidrug-Resistant Acinetobacter baumannii Bacterial Infections in Burn Wounds

Multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) is one of the major pathogens present in burn wound infections. Biofilm formation makes it further challenging to treat with clinically available antibiotics. In the current work, we isolated the A. baumannii-specific bacteriophages (BPABΦ1), loaded into the chitosan microparticles followed by dispersion in gel, and evaluated therapeutic efficacy against MDR A. baumannii clinical strains. Isolated BPABΦ1 were found to belong to the Corticoviridae family, with burst size 102.12 ± 2.65 PFUs per infected host cell. The BPABΦ1 loaded chitosan microparticles were evaluated for quality attributes viz. size, PDI, surface morphology, in vitro release, etc. The developed formulation exhibited excellent antibiofilm eradication potential in vitro and effective wound healing after topical application.

Recent advancements in nanotechnology-based bacteriophage delivery strategies against bacterial ocular infections

Antibiotic resistance is growing as a critical challenge in a variety of disease conditions including ocular infections leading to disastrous effects on the human eyes. Staphylococcus aureus (S. aureus) mediated ocular infections are very common affecting different parts of the eye viz. vitreous chamber, conjunctiva, cornea, anterior and posterior chambers, tear duct, and eyelids. Blepharitis, dacryocystitis, conjunctivitis, keratitis, endophthalmitis, and orbital cellulitis are some of the commonly known ocular infections caused by S. aureus. Some of these infections are so fatal that they could cause bilateral blindness like panophthalmitis and orbital cellulitis, which is caused by methicillin-resistant S. aureus (MRSA) and vancomycin-resistance S. aureus (VRSA). The treatment of S. aureus infections with known antibiotics is becoming gradually difficult because of the development of resistance against multiple antibiotics. Apart from the different combinations and formulation strategies, bacteriophage therapy is growing as an effective alternative to treat such infections. Although the superiority of bacteriophage therapy is well established, yet physical factors (high temperatures, acidic pH, UV-rays, and ionic strength) and pharmaceutical barriers (poor stability, low in-vivo retention, controlled and targeted delivery, immune system neutralization, etc.) have the greatest influence on the viability of phage virions (also phage proteins). A variety of Nanotechnology based formulations such as polymeric nanoparticles, liposomes, dendrimers, nanoemulsions, and nanofibres have been recently reported to overcome the above-mentioned obstacles. In this review, we have compiled all these recent reports and discussed bacteriophage-based nanoformulations techniques for the successful treatment of ocular infections caused by multidrug-resistant S. aureus and other bacteria.

Endorsement of TNBC Biomarkers in Precision Therapy by Nanotechnology

Breast cancer is a heterogeneous disease which accounts globally for approximately 1 million new cases annually, wherein more than 200,000 of these cases turn out to be cases of triple-negative breast cancer (TNBC). TNBC is an aggressive and rare breast cancer subtype that accounts for 10-15% of all breast cancer cases. Chemotherapy remains the only therapy regimen against TNBC. However, the emergence of innate or acquired chemoresistance has hindered the chemotherapy used to treat TNBC. The data obtained from molecular technologies have recognized TNBC with various gene profiling and mutation settings that have helped establish and develop targeted therapies. New therapeutic strategies based on the targeted delivery of therapeutics have relied on the application of biomarkers derived from the molecular profiling of TNBC patients. Several biomarkers have been found that are targets for the precision therapy in TNBC, such as EGFR, VGFR, TP53, interleukins, insulin-like growth factor binding proteins, c-MET, androgen receptor, BRCA1, glucocorticoid, PTEN, ALDH1, etc. This review discusses the various candidate biomarkers identified in the treatment of TNBC along with the evidence supporting their use. It was established that nanoparticles had been considered a multifunctional system for delivering therapeutics to target sites with increased precision. Here, we also discuss the role of biomarkers in nanotechnology translation in TNBC therapy and management.

A Current Review on Analytical Tools for Determination of New Oral Antidiabetic Drugs, Empagliflozin, Linagliptin and Biguanides in Bulk Materials, Pharmaceuticals & Biological Samples

Worldwide the R & D divisions of Pharma industry are actively involved in the development of new therapeutic agents. These agents may be either new entities or partial structural modification of the existing one. The recent FDA statistics represent that the average number of drug filings are increasing every year in the thrust areas like anti-cancer agents, anti-diabetic, antibiotics, cardio-vascular drugs, respiratory drugs etc. Sodium glucose co-transporter-2(SGLT-2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and biguanides are effective oral anti-diabetic agents used in treatment of type 2 Diabetes Mellitus. Therefore, the necessity to explore and compare the existing analytical and bioanalytical assays used for determination of such drugs either single or in combination is crucial. Many methods were reported in the literature for the bio-analysis and analysis of four novel gliptins combinations, empagliflozin-linagliptin, empagliflozin-metformin HCl, linagliptin-metformin HCl, empagliflozin-linagliptin-metformin HCl combination with application on Glyxambi®, Synjardy®, Jentadueto®, Trijardy® XR tablets respectively. Furthermore, this review offered an overview of different methods used for determination of every drug alone as empagliflozin from SGLT-2 inhibitors, linagliptin from DPP-4 inhibitors and metformin from biguanides in a tabulated comparative way. Moreover, the current review emphasizes the most common stability indicating assays to be of interest to the analysts in the area of drug control. This review helps in understanding the further need for the development of analytical methods for the estimation of such drugs.

Epitope mapping of the White Spot Syndrome Virus (WSSV) VP28 monoclonal antibody through combined in silico and in vitro analysis reveals the potential antibody binding site

White Spot Syndrome Virus (WSSV) infecting shrimp is an enveloped double-stranded DNA virus. The WSSV is a member of the genus Whispovirus. The envelope protein VP28 is the most investigated protein of WSSV. In the present study, the epitope mapping of the monoclonal antibody (MAb) C-33 was carried out. Based on the epitope mapping results, an antigen-antibody interaction model was derived. Peptide scanning and confirmation of epitopes of MAb C-33 were carried out using the sequence data. The MAb was reactive to the epitope of both recombinant VP28 and the whole virus. The results of the study indicated the presence of an epitope region. The epitope region is found positioned within two peptides, covering 13 amino acids. Framework and CDR (complementarity determining regions) of heavy and light chain (VH & VL) sequences showed identity to germline immunoglobulin sequences. The Web Antibody Modelling (WAM) selected for further evaluation based on a comparative analysis of WAM and Rosetta server-generated models of the Fv region. The docking study using WAM generated model revealed that the residues from LEU98 to GLY105 are active in antibody binding. The findings of this study could form a structural basis for further research in VP28 based diagnostics and therapeutics or vaccine discovery.

Serum 25-hydroxyvitamin D levels and incident falls in older women

Three hundred eighty-seven home-dwelling older women were divided into quartiles based on mean serum 25-hydroxyvitamin D (S-25(OH)D) levels. The rates of falls and fallers were about 40% lower in the highest S-25(OH)D quartile compared to the lowest despite no differences in physical functioning, suggesting that S-25(OH)D levels may modulate individual fall risk.

INTRODUCTION

Vitamin D supplementation of 800 IU did not reduce falls in our previous 2-year vitamin D and exercise RCT in 70-80 year old women. Given large individual variation in individual responses, we assessed here effects of S-25(OH)D levels on fall incidence.

METHODS

Irrespective of original group allocation, data from 387 women were explored in quartiles by mean S-25(OH)D levels over 6-24 months; means (SD) were 59.3 (7.2), 74.5 (3.3), 85.7 (3.5), and 105.3 (10.9) nmol/L. Falls were recorded monthly with diaries. Physical functioning and bone density were assessed annually. Negative binomial regression was used to assess incidence rate ratios (IRRs) for falls and Cox-regression to assess hazard ratios (HR) for fallers. Generalized linear models were used to test between-quartile differences in physical functioning and bone density with the lowest quartile as reference.

RESULTS

There were 37% fewer falls in the highest quartile, while the two middle quartiles did not differ from reference. The respective IRRs (95% CI) for falls were 0.63 (0.44 to 0.90), 0.78 (0.55 to 1.10), and 0.87 (0.62 to 1.22), indicating lower falls incidence with increasing mean S-25(OH)D levels. There were 42% fewer fallers (HR 0.58; 040 to 0.83) in the highest quartile compared to reference. Physical functioning did not differ between quartiles.

CONCLUSIONS

Falls and faller rates were about 40% lower in the highest S-25(OH)D quartile despite similar physical functioning in all quartiles. Prevalent S-25(OH)D levels may influence individual fall risk. Individual responses to vitamin D treatment should be considered in falls prevention.

Annexin A5 levels or circulating microparticles: what we see depends mainly on what we look for

Click here to view the article Letter to the Editor by C. Reutelingsperger et al.

Cost-effectiveness of vitamin D supplementation and exercise in preventing injurious falls among older home-dwelling women: findings from an RCT

This study assessed the cost-effectiveness of vitamin D supplementation and exercise, separately and combined, in preventing medically attended injurious falls among older home-dwelling Finnish women. Given a willingness to pay of €3,000 per injurious fall prevented, the exercise intervention had an 86 % probability of being cost-effective in this population.

INTRODUCTION

The costs of falling in older persons are high, both to the individual and to society. Both vitamin D and exercise have been suggested to reduce the risk of falls. This study assessed the cost-effectiveness of vitamin D supplementation and exercise, separately and combined, in preventing medically attended injurious falls among older Finnish women.

METHODS

Economic evaluation was based on the results of a previously published 2-year randomized controlled trial (RCT) where 409 community-dwelling women aged 70 to 80 years were recruited into four groups: (1) no exercise + placebo (D-Ex-), (2) no exercise + vitamin D 800 IU/day (D+Ex-), (3) exercise + placebo (D-Ex+), and (4) exercise + vitamin D 800 IU/day (D+Ex+). The outcomes were medically attended injurious falls and fall-related health care utilization costs over the intervention period, the latter evaluated from a societal perspective based on 2011 unit costs. Incremental cost-effectiveness ratios (ICER) were calculated for the number of injurious falls per person-year prevented and uncertainty estimated using bootstrapping.

RESULTS

Incidence rate ratios (95 % CI) for medically attended injurious falls were lower in both Ex+ groups compared with D-Ex-: 0.46 (0.22 to 0.95) for D-Ex+, 0.38 (0.17 to 0.81) for D+Ex+. Step-wise calculation of ICERs resulted in exclusion of D+Ex- as more expensive and less effective. Recalculated ICERs were €221 for D-Ex-, €708 for D-Ex+, and €3,820 for D+Ex+; bootstrapping indicated 93 % probability that each injurious fall avoided by D-Ex+ per person year costs €708. At a willingness to pay €3,000 per injurious fall prevented, there was an 85.6 % chance of the exercise intervention being cost-effective in this population.

CONCLUSIONS

Exercise was effective in reducing fall-related injuries among community-dwelling older women at a moderate cost. Vitamin D supplementation had marginal additional benefit. The results provide a firm basis for initiating feasible and cost-effective exercise interventions in this population.

Dental notation for primary teeth: a review and suggestion of a novel system

BACKGROUND

Tooth designation systems are routinely used in dental practice, for identification of teeth, recording dental data and communication among dental professionals. There are various dental notations systems for the primary and permanent dentition. The most popular are the Zsigmondy-Palmer system, the Universal Numbering System, and the FDI system. Others includes the Victor Haderup system, the Woelfel system, and the MICAP system. The majority of dental notations are focused on permanent teeth and are modified for primary teeth, even though the latter erupt before the permanent dentition.

CONCLUSION

Advantages and disadvantages of notations for primary dentition are discussed and compared to a new alphanumeric system for primary teeth which is considered simple and convenient.

Development of a monoclonal antibody-based flow-through immunoassay (FTA) for detection of white spot syndrome virus (WSSV) in black tiger shrimp Penaeus monodon

A flow-through immunoassay (FTA), an improved version of immunodot, was developed using a nitrocellulose membrane baked onto adsorbent pads enclosed in a plastic cassette to detect white spot syndrome virus (WSSV) in shrimp. Sharp purple dots developed with WSSV against the white background of the nitrocellulose membrane. The detection limits of WSSV by the FTA and immunodot were 0.312 and 1.2 μg mL(-1) crude WSSV protein, respectively. The FTA could be completed in 8-10 min compared with 90 min for immunodot. The FTA was 100 times more sensitive than 1-step polymerase chain reaction (PCR) and in between that of the 1- and 2-step PCR protocol recommended by the Office of International Epizootics (OIE). In experimental, orally infected shrimp post-larvae, WSSV was first detected 14, 16 and 18 h post-infection (hpi) by FTA, immunodot and one-step PCR, respectively. The FTA detected WSSV 2 and 4 h earlier than immunodot and one-step PCR, respectively. The FTA was more sensitive (25/27) than one-step PCR (23/27) and immunodot (23/27) for the detection of WSSV from white spot disease outbreak ponds. The reagent components of the FTA were stable giving expected results for 6 m at 4-8 °C. The FTA is available as a rapid test kit called 'RapiDot' for the early detection of WSSV under field conditions.

Removal of Brilliant Green from wastewater using conventional and ultrasonically prepared poly(acrylic acid) hydrogel loaded with kaolin clay: A comparative study

The present work deals with the removal of Brilliant Green dye from wastewater using a poly(acrylic acid) hydrogel composite (PAA-K hydrogel) prepared by incorporation of kaoline clay. The composite has been synthesized using ultrasound assisted polymerization process as well as the conventional process, with an objective of showing the better effectiveness of ultrasound assisted synthesis. It has been observed that the hydrogel prepared by ultrasound assisted polymerization process showed better results. The optimum conditions for the removal of dye are pH of 7, temperature of 35°C, initial dye concentration of 30mg/L and hydrogel loading of 1g. The extent of removal of dye increased with an increase in the contact time and initial dye concentration. A pseudo-second-order kinetic model has been developed to explain the adsorption kinetics of dye on the PAA-K hydrogel. Thermodynamic and kinetic parameters indicate that the adsorption process is spontaneous in nature and the PAA-K hydrogel prepared by ultrasound process is a promising adsorbent compared to conventional process. The obtained adsorption data has also been fitted into commonly used adsorption isotherms and it has been found that Freundlich as well as Langmuir adsorption isotherm models fits well to the experimental results.

Sarcopenia and osteopenia among 70-80-year-old home-dwelling Finnish women: prevalence and association with functional performance

This study showed that the prevalence of sarcopenia (low muscle mass and performance) among 70-80-year-old home-dwelling Finnish women is very low, while every third woman has WHO-based osteopenia (low bone mass). Muscle mass and derived indices of sarcopenia were not significantly related to measures of functional ability.

INTRODUCTION

This study aims to determine the prevalence of sarcopenia and osteopenia among four hundred nine 70-80-year-old independently living Finnish women. The study compared consensus diagnostic criteria for age-related sarcopenia recently published by the European Working Group on Sarcopenia in Older People (EWGSOP) and the International Working Group on Sarcopenia (IWG) and assessed their associations with functional ability.

METHODS

Femoral bone mineral density and body composition were measured with dual-energy X-ray absorptiometry. Skeletal muscle mass index (SMI), gait speed, and handgrip strength were used for sarcopenia diagnosis. Independent samples t tests determined group differences in body composition and functional ability according to recommended diagnostic cutpoints. Scatter plots were used to illustrate the correlations between the outcome measures used for diagnosis.

RESULTS

Prevalence of sarcopenia was 0.9 and 2.7 % according to the EWGSOP and IWG, respectively. Thirty-six percent of the women had WHO-based osteopenia. Women with higher gait speed had significantly lower body weight and fat mass percentage, higher lean mass percentage, and better functional ability. Women with a low SMI weighed significantly less, with no significant differences in other outcome measures. SMI, gait speed, and grip strength were significantly correlated.

CONCLUSIONS

Our study suggests that when using consensus definitions, sarcopenia is infrequent among older home-dwelling women while every third woman has osteopenia. In clinical practice, attention should be paid to the decline in functional ability rather than focusing on low muscle mass alone.

Abstract A50: Nanobiocojugates of differential imaging and treatment of brain metastatic tumors

Introduction: A significant clinical problem with brain metastatic (BM) tumors is drug delivery and diagnostic imaging to verify MRI enhancement(s) for planning treatment. MRI enhancement in cancer patient's brain might result from infection after chemotherapy that impairs immune system; metastasis from primary lung/breast cancer; or a new primary brain tumor. Unlike lung/breast, brain biopsies are often technically impossible. Therefore, there is urgent need for the development of effective theranostic (dual therapy and diagnostic) systems against brain metastatic cancer.

Most chemotherapeutic drugs or therapeutic monoclonal antibodies (mAb), Trastuzumab, Cetuximab, and Rituximab, are effective for primary tumor treatment but cannot penetrate blood brain barrier (BBB) failing to treat brain metastasis.

We used a natural nanobiopolymer, polymalic acid (PMLA), as a nanoplatform for the family of tumor-targeted PolycefinTM drugs to provide differential brain tumor imaging and treatment.

Methods: Three xenogeneic orthotropic human brain metastatic tumors, MDA-MB-474, HER2+ breast cancer; A549 lung cancer, and MDA-MB-468, triple negative breast cancer (TNBC), both EGFR+, were inoculated stereotactically into the brain of mice.

For diagnostic imaging, PolycefinTM was used with covalently attached MRI tracer Gadolinium (Gd-DOTA). Morpholino antisense oligonucleotides (AON) were conjugated to PolycefinTM to specifically inhibit gene/protein expression to block tumor growth. The combination of cell surface targeting mAbs, including anti-transferrin receptor (TfR) mAb for drug BBB transcytosis, and AONs to multiple tumor markers on the same delivery polymer was used for anti-tumor treatment.

MRI 1H imaging was performed on a 9.4-Tesla small animal MRI system. Treatment groups of animals included (1) HER2+ MDA-MB-474 breast cancer metastases targeted with PMLA-Gd-DOTA/HER2 mAb/TfR mAb; (2) EGFR+ MDA-MB-468 TNBC metastases targeted with PMLA-Gd-DOTA/EGFR mAb/TfR mAb; and (3) Controls for all treatments inoculated with PMLA-IgG mAb and clinical Gd.

Unpublished Results. Imaging: Dynamic T1 analysis. Similar data for specific tumor imaging were obtained for brain-implanted lung and breast tumors: the inverse of T1-1 relaxation time (proportional to Gd concentration) was measured in healthy brain part and in the tumor. T1-1 time dependence for Gd-DOTA-Polycefin (T1-1 ratio tumor/normal brain) was compared with clinically used Gd MRI agent, MultiHance®. After reaching a maximum, high T1-1 relative values prevailed for several hours for Gd-DOTA-mAb-Polycefin, but declined rapidly for Gd. High contrast for Gd was seen in 20 min, whereas that for Gd-DOTA-Polycefin peaked in 45-60 min, and remained for up to 3 hrs. By differential MRI with anti-HER2 (Trastuzumab) or anti-EFGR (Cetuximab) mAb attached covalently to the nanoplatform, we were able to differentiate HER2+ from EGFR+ metastatic brain tumors with corresponding imaging controls.

Treatment: Animal survival after Polycefin treatment of various brain metastases was significantly higher than in untreated (PBS) or therapeutic mAb (Herceptin or Cetuximab) treated animals. These survival increases were as follows: 66% for lung cancer metastasis, 47% for HER2+ breast cancer metastasis, and 81% for TNBC metastasis.

Conclusions. We have developed a system for differential imaging and treatment of various metastatic brain tumors based on specific metastasis targeting, and inhibition of expression of tumor-specific genes/proteins. Systemic treatment with this system resulted in significantly increased survival of brain metastatic tumor-bearing animals.

Citation Format: Julia Y. Ljubimova, R. Patil, P. Gangalum, S. Wagner, S. Inoue, H. Ding, J. Portilla, K. Rekechenetskiy, K. Bindu, J. Markman, A. Chesnokova, K. L. Black, E. Holler. Nanobiocojugates of differential imaging and treatment of brain metastatic tumors. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A50.

296 IN VITRO DIFFERENTIATION OF PORCINE BONE MARROW-DERIVED MESENCHYMAL STEM CELLS INTO HEPATOCYTE-LIKE CELLS

Mesenchymal stem cells (MSC) are isolated from bone marrow or other tissues, and have properties of self renewal and multilineage differentiation ability. The current study investigated the in vitro differentiation potential of porcine bone marrow derived MSCs into hepatocyte-like cells. The MSC were isolated from the bone marrow of adult miniature pigs (7 months old, T-type, PWG Micro-pig®, PWG Genetics, Seoul, Korea) and adherent cells with fibroblast-like morphology were cultured on plastic. Isolated MSCs were positive for CD29, CD44, CD73, CD90, and vimentin, and negative for CD34, CD45, major histocompatibility complex-class II (MHC-class II), and swine leukocyte antigen-DR (SLA-DR) by flow cytometry analysis. Further, trilineage differentiation of MSC into osteocytes (alkaline phosphatase, von Kossa and Alizarin red), adipocytes (Oil Red O), and chondrocytes (Alcian blue) was confirmed. Differentiation of MSC into hepatocyte-like cells was induced with sequential supplementation of growth factors, cytokines, and hormones for 21 days as described previously (Taléns-Visconti et al. 2006 World J. Gastroenterol. 12, 5834–5845). Morphological analysis, expression of liver-specific markers, and functional assays were performed to evaluate the hepatic differentiation of MSC. Under hepatogenic conditions, MSC acquired cuboidal morphology with cytoplasmic granules. These hepatocyte-like cells expressed α-fetoprotein (AFP), albumin (ALB), cytokeratin 18 (CK18), cytochrome P450 7A1 (CYP7A1), and hepatocyte nuclear factor 1 (HNF-1) markers by immunofluorescence assay. In addition, the expression of selected markers was demonstrated by Western blotting analysis. In accordance with these features, RT-PCR revealed transcripts of AFP, ALB, CK18, CYP7A1, and HNF-1α. Further, the relative expression levels of these transcripts were analysed by quantitative RT-PCR after normalizing to the expression of the endogenous control, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Data were analysed statistically by one-way ANOVA using PASW statistics 18 (SPSS Inc., Chicago, IL, USA), and significance was considered at P < 0.05. The results showed that the relative expressions of selected marker genes in hepatocyte-like cells were significantly increased compared with that in untreated MSC. The generated hepatocyte-like cells showed glycogen storage as analysed by periodic acid-Schiff (PAS) staining. Moreover, the induced cells produced urea at Day 21 of culture compared with control MSC. In conclusion, our results indicate the potential of porcine MSC to differentiate in vitro into hepatocyte-like cells. Further studies on the functional properties of hepatocyte-like cells are needed to use porcine MSC as an ideal source for liver cell therapy and preclinical drug evaluation. This work was supported by Basic Science Research Program through the National Research Foundation (NRF), funded by the Ministry of Education, Science and Technology (2010-0010528) and the Next-Generation BioGreen 21 Program (No. PJ009021), Rural Development Administration, Republic of Korea.