3D Printed Surgical Simulation Models as educational tool by maxillofacial surgeons.

INTRODUCTION: The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions. MATERIALS AND METHODS: Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire. RESULTS: Because of slightly different density and filament prices, each silicon-covered model costs between 1.40-1.60 USD (ABS) and 1.80-2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages. CONCLUSION: The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost-efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures.

Discrimination Factors and Incorporation Rates for Organic Matrix in Shark Teeth Based on a Captive Feeding Study.

Sharks migrate annually over large distances and occupy a wide variety of habitats, complicating analysis of lifestyle and diet. A biogeochemical technique often used to reconstruct shark diet and environment preferences is stable isotope analysis, which is minimally invasive and integrates through time and space. There are previous studies that focus on isotopic analysis of shark soft tissues, but there are limited applications to shark teeth. However, shark teeth offer an advantage of multiple ecological snapshots and minimum invasiveness during removal because of their distinct conveyor belt tooth replacement system. In this study, we analyze δ13C and δ15N values of the organic matrix in leopard shark teeth (Triakis semifasciata) from a captive experiment and report discrimination factors as well as incorporation rates. We found differences in tooth discrimination factors for individuals fed different prey sources (mean ± SD; Δ13Csquid = 4.7‰ ± 0.5‰, Δ13Ctilapia = 3.1‰ ± 1.0‰, Δ15Nsquid = 2.0‰ ± 0.7‰, Δ15Ntilapia = 2.8‰ ± 0.6‰). In addition, these values differed from previously published discrimination factors for plasma, red blood cells, and muscle of the same leopard sharks. Incorporation rates of shark teeth were similar for carbon and nitrogen (mean ± SE; λC = 0.021 ± 0.009, λN = 0.024 ± 0.007) and comparable to those of plasma. We emphasize the difference in biological parameters on the basis of tissue substrate and diet items to interpret stable isotope data and apply our results to stable isotope values from blue shark (Prionace glauca) teeth to illustrate the importance of biological parameters to interpret the complex ecology of a migratory shark.

Genome-wide expression changes induced by HTLV-1 Tax: evidence for MLK-3 mixed lineage kinase involvement in Tax-mediated NF-kappaB activation.

The Tax protein of human T-lymphotropic virus type 1 (HTLV-1), an oncoprotein that transactivates viral and cellular genes, plays a key role in HTLV-1 replication and pathogenesis. We used cDNA microarrays to examine Tax-mediated transcriptional changes in the human Jurkat T-cell lines JPX-9 and JPX-M which express Tax and Tax-mutant protein, respectively, under the control of an inducible promoter. Approximately 300 of the over 2000 genes examined were differentially expressed in the presence of Tax. These genes were grouped according to their function and are discussed in the context of existing findings in the literature. There was strong agreement between our results and genes previously reported as being Tax-responsive. Genes that were differentially expressed in the presence of Tax included those related to apoptosis, the cell cycle and DNA repair, signaling factors, immune modulators, cytokines and growth factors, and adhesion molecules. Functionally, we provide evidence that one of these genes, the mixed-lineage kinase MLK-3, is involved in Tax-mediated NF-kappa-B signaling. Our current results provide additional insights into Tax-mediated signaling.

Individual prognoses of long-term responses to antiretroviral treatment based on virological, immunological and pharmacological parameters measured during the first week under therapy.

OBJECTIVE: To predict long-term (12 weeks or longer) virological responses to antiretroviral treatment from measurements made during the first few days on therapy. METHODS: Forty-one HIV-1-infected children were treated with ritonavir for 12 weeks followed by triple drug combination treatment, and the kinetics of virus decay in plasma, ritonavir concentration and CD4 cell counts were measured. A robust multivariate pattern recognition method was used for prediction of the longterm virological responses. RESULTS: The virus decay rate constants calculated from measurements of plasma viral RNA concentrations on the first, second, third, fourth and seventh day on therapy, the drug concentrations in the plasma on day seven, and the pretreatment levels of viral RNA and CD4 cell counts, correlated with long-term levels of plasma HIV-1 RNA. The combination of these parameters contained sufficient information for correct and robust prediction of the long-term response in 88% of the treated children. The predictions of individual responses were stable as demonstrated by a cross-validation analysis, which was highly statistically significant (r=0.87) and specific. CONCLUSION: These results demonstrate that multiple parameters determine the response to antiretroviral therapy and offer a very early measure of individual long-term responses, suggesting that treatment could be optimized after few days of therapy.

Cytomegalovirus retinitis in an infant with acquired immunodeficiency syndrome.

A case of cytomegalovirus retinitis in an infant with acquired immunodeficiency syndrome (AIDS) is described. Although well recognized as an ocular manifestation of AIDS in adults, only one case of the necrotic retinitis caused by cytomegalovirus has been described in a child with AIDS. Intravenous treatment with ganciclovir resulted in substantial ocular improvement, despite the advanced nature of the disease in one eye in which there was also secondary neovascular glaucoma. Home maintenance treatment was used via Broviac catheter. The patient later died following pulmonary infection with Pneumocystis carinii.

A phase I/II study of the protease inhibitor indinavir in children with HIV infection.

BACKGROUND: Indinavir, an inhibitor of the human immunodeficiency virus type 1 (HIV-1) protease, is approved for the treatment of HIV infection in adults when antiretroviral therapy is indicated. We evaluated the safety and pharmacokinetic profile of the indinavir free-base liquid suspension and the sulfate salt dry-filled capsules in HIV-infected children, and studied its preliminary antiviral and clinical activity in this patient population. In addition, we evaluated the pharmacokinetic profile of a jet-milled suspension after a single dose. METHODS: Previously untreated children or patients with progressive HIV disease despite antiretroviral therapy or with treatment-associated toxicity were eligible for this phase I/II study. Three dose levels (250 mg/m2, 350 mg/m2, and 500 mg/m2 per dose given orally every 8 h) were evaluated in 2 age groups (<12 years and >/=12 years). Indinavir was initially administered as monotherapy and then in combination with zidovudine and lamivudine after 16 weeks. RESULTS: Fifty-four HIV-infected children (ages 3.1 to 18.9 years) were enrolled. The indinavir free-base suspension was less bioavailable than the dry-filled capsule formulation, and therapy was changed to capsules in all children. Hematuria was the most common side effect, occurring in 7 (13%) children, and associated with nephrolithiasis in 1 patient. The combination of indinavir, lamivudine, and zidovudine was well tolerated. The median CD4 cell count increased after 2 weeks of indinavir monotherapy by 64 cells/mm3, and this was sustained at all dose levels. Plasma ribonucleic acid levels decreased rapidly in a dose-dependent way, but increased toward baseline after a few weeks of indinavir monotherapy. CONCLUSIONS: Indinavir dry-filled capsules are relatively well tolerated by children with HIV infection, although hematuria occurs at higher doses. Future studies need to evaluate the efficacy of indinavir when combined de novo with zidovudine and lamivudine.

A phase I/II study of the protease inhibitor ritonavir in children with human immunodeficiency virus infection.

BACKGROUND: Ritonavir, a potent antiretroviral protease inhibitor, has been approved for the treatment of adults and children with human immunodeficiency virus (HIV) infection. In a phase I/II study, we assessed the safety, tolerability, and pharmacokinetic profile of the oral solution of ritonavir in HIV-infected children and studied the preliminary antiviral and clinical effects. METHODS: HIV-infected children between 6 months and 18 years of age were eligible. Four dose levels of ritonavir oral solution (250, 300, 350, and 400 mg/m given every 12 hours) were evaluated in two age groups (2 years). Ritonavir was administered alone for the first 12 weeks and then in combination with zidovudine and/or didanosine. Clinical and laboratory parameters were monitored every 2 to 4 weeks. RESULTS: A total of 48 children (median age, 7.7 years; range, 0.5 to 14.4 years) were included in this analysis. Dose-related nausea, diarrhea, and abdominal pain were the most common toxicities and resulted in discontinuation of ritonavir in 7 children. Ritonavir was well absorbed at all dose levels, and plasma concentrations reached a peak 2 to 4 hours after a dose. CD4 cells counts increased by a median of 79 cells/mm3 after 4 weeks of monotherapy and were maintained throughout the study. Plasma HIV RNA decreased by 1 to 2 log10 copies/mL within 4 to 8 weeks of ritonavir monotherapy, and this level was sustained in patients enrolled at the highest dose level of 400 mg/m for the 24-week period. CONCLUSIONS: The oral solution of ritonavir has potent antiretroviral activity as a single agent and is relatively well tolerated by children when administered alone or in combination with zidovudine or didanosine.

The expression of the essential nuclear splicing factor SC35 is altered by human immunodeficiency virus infection.

In order to identify cellular genes differentially expressed during human immunodeficiency virus 1 (HIV-1) infection, we conducted a screen using differential display. The sequence of one of the clones, 0085, was identical to a sequence present in the RNA splicing factor SC35. Since splicing is an essential point of control during HIV gene expression, we carried out additional experiments to examine SC35 expression during HIV infection. RNA blots confirmed that SC35 RNA was induced following HIV infection; a 2-3-fold increase in expression of SC35 RNA was detected by day 2 of HIV infection. Fluorescence-activated cell-sorting revealed concomitant increases in SC35 protein and double staining studies demonstrated that increases in SC35 protein occurred specifically in the HIV-infected cells. Laser scanning confocal microscopy revealed SC35 was associated with 2 microm 'nuclear speckles' in both infected and uninfected cells, suggesting that increases in SC35 accumulated in these nuclear structures and that HIV infection did not alter the intracellular distribution of SC35. These findings indicate that an essential splicing factor is induced after HIV infection, suggesting that the consequences of HIV infection include alterations in relative levels of a splicing factor.

Umbilical Cord Blood Mononuclear Cell HIV-1 LTR Binding Activities.

Vertically transmitted HIV disease constitutes a significant problem in pediatrics. In order to characterize some of the possible host factors involved in HIV replication in fetuses and newborns, we surveyed the HIV-1 LTR binding factors present in nuclear extracts from cord blood mononuclear cells. A series of electrophoretic mobility shift assays (EMSAs) showed that protein extracts from cord blood interacted with several regions of the HIV LTR. The most prominent binding activities involved the NF-kB sites, but other regions of the LTR also showed factor binding with the cord blood extracts. Some of these cord blood extract binding activities displayed qualitative differences when compared to adult peripheral blood mononuclear cell extracts in EMSA and UV cross-linking studies. Transient transfection experiments indicated that the NF-kB and Sp1 sequences were important for wild type levels of expression in cord blood cells, but that additional sequences 5' to the NF-kB sites also contributed activity. Thus, factors that interact with many of the well-known HIV LTR regulatory sites are present in cord blood cells. However, certain qualitative differences distinguished cord blood and adult peripheral blood binding activities and these may contribute to pathogenesis of HIV infection in neonates.

Analysis of the human immunodeficiency virus long terminal repeat by in vitro transcription competition and linker scanning mutagenesis.

Previous studies designed to map the transcriptional regulatory sequences of the human immunodeficiency virus (HIV) long terminal repeat (LTR) have shown disparate results depending on the method of analysis. Experiments have shown that deletions 5' to -104 (relative to the transcription start site, +1) are not required for transcription in vitro, while other experiments have shown that various mutations in this 5' region of the HIV-1 LTR affect both reporter gene activity in transient expression systems and viral growth. To correlate in vitro and in vivo findings, we performed in vitro transcription competition studies to define minimal sequences necessary for competitive factor binding or competitive transcription complex formation. Using normal HeLa cell nuclear extracts, we found that transcription of a reporter gene run by the U3-R region was efficiently competed only by intact LTR DNA fragments representing virtually the entire U3-R region (-453 to +80). Smaller subfragments of the LTR were less effective competitors; these included fragments from -453 to -159, which had a modest competitive ability at higher competitor concentrations, -159 to +80, and -402 to -34, which were both relatively poor competitors. These findings indicate that although the U3-R region truncated to -104 is able to promote in vitro transcription, a more stable transcription complex appears to form on the entire U3-R region. Hence sequences between -453 and -104 appear to be significant in transcription complex formation. In vivo transfection competition studies confirmed these findings. Specific sequences between -453 and -104 which may affect expression or transcription complex formation were mapped using a set of linker-scanning mutants spanning the LTR.(ABSTRACT TRUNCATED AT 250 WORDS)

The molecular biology of HIV. Insights into pathogenesis and targets for therapy.

In the past 10 years, a large number of investigators have produced an enormous amount of information concerning the molecular biology of HIV. These studies at the most basic biological level have provided essential insights into the pathogenesis of the disease. They have supplied the information necessary for the creation of the antiviral therapies now available and have indicated the direction for the development of new therapies now in clinical trials and under investigation. Although the relatively ineffective therapies currently available serve as a constant source of disappointment for those practitioners who care for HIV-infected patients, there is some comfort to be gained from the rapid pace of investigation into the basic biology of the virus and the certainty that any more effective therapy must build upon the basic biological knowledge already obtained. A detailed study of some of the unique features observed during pediatric and perinatal HIV infection, particularly the relatively shortened time from infection to symptoms and the relative importance of CNS disease, may suggest new therapeutic approaches that will benefit both adult and pediatric patients. Finally, a comprehensive knowledge of HIV biology is an essential requirement for therapeutic maneuvers designed to interrupt the transmission of HIV from mother to child.

Mechanisms and pathways of congenital infections.

Fetal and neonatal infections can occur at different times during pregnancy, from conception to birth. Infections that take place near the time of conception often destroy the zygote or embryo and only rarely leave definitive evidence. The mother can transmit the infection to her fetus through several routes, but the most likely routes are through ascending infections and through the blood. The inability of most agents to infect the early embryo probably depends largely on local barriers to the infectious agent, such as the zona pellucida. Some viruses, however, because of their systems for gene regulation of expression, can infect only embryos of certain developmental stages. Certain retroviruses can infect embryos, integrate into cellular DNA, and become part of the germline. After implantation, most infectious agents reach the fetus hematogenously. Organisms circulating in the mother reach and infect the placenta. They then may breach the placenta, gain access to the fetal circulation, and disseminate through the fetal body. Agents with particular tropisms infect particular organs and cause particular symptom complexes. The damage done by the organisms depends largely on the gestational age of the fetus at the time of the infection. The ability of the agent to infect or damage the fetus at all often depends on whether the mother is experiencing a primary infection or has previously mounted an effective immune response. Agents harm the fetus through direct destruction of parenchymal cells, through destruction of blood vessels and resulting infarction, through continued replication in fetal and neonatal tissues, through altering the growth parameters of various fetal tissues, and through provoking autoimmune responses. Infections that begin in the perinatal period usually infect the fetus by direct inoculation from infected foci in the birth canal or through direct contact with large amounts of infected maternal body fluids. Direct tissue destruction of the immediate sequelae of invasive infections usually causes the fetal damage from these perinatally acquired agents. The clinical features of the disease that begin in this period provide an opportunity for effective therapeutic intervention. Understanding the routes of fetal infection and the mechanisms underlying fetal damage from infection will help in devising strategies for preventing and treating congenital infections.

Burkitt's/Burkitt's-like lymphoma presenting as bacterial sinusitis in two HIV-infected children.

Two children (ages 12 and 13 years) with transfusion-acquired human immunodeficiency virus (HIV) infection presented with facial pain and rhinorrhea. Radiographic imaging showed extensive paranasal sinus disease, presumed to be bacterial sinusitis, and the patients were treated with broad-spectrum oral antibiotics. Both patients were unresponsive to oral agents and were switched to intravenous antibiotics. Despite aggressive antimicrobial therapy, one patient (case 1) developed increased periorbital swelling and proptosis, and the other patient (case 2) developed symptoms of nasopharyngeal obstruction. Repeat imaging showed progression of the infiltrative process extending from the paranasal sinuses into the orbit (case 1), and nasopharynx (case 2). Surgical exploration and tissue biopsies were performed on both patients and the histopathology was consistent with Burkitt's/Burkitt's-like lymphoma. Combination systemic and intrathecal chemotherapy resulted in a complete remission in both patients. These reports illustrate the fact that Burkitt's/Burkitt's-like lymphoma in the paranasal sinuses may initially masquerade as an acute bacterial sinusitis. The ability of the tumor to extend rapidly from the sinuses into the orbit and nasopharynx reinforces the importance of early diagnosis and treatment. Burkitt's/Burkitt's-like lymphoma in the paranasal sinuses has not been previously described in HIV-infected children.

Efficacy of dental radiographic practices: options for image receptors, examination selection, and patient selection.

Many technical factors and treatment philosophies affect the way dental radiology is practiced. Some, like minimum tube filtration, are legislated. Others, like proper darkroom techniques, are universally acknowledged as essential. Still others, like the selection of an image receptor and the selection of the type of examination, are the subject of much discussion and debate. This article addresses some of the more controversial options and choices facing dental practitioners by reviewing the standard assessment techniques available to help make appropriate decisions, by summarizing and analyzing available data, and by offering recommendations for practice.

An investigation of accessory foramina in furcation areas of human primary molars: Part 1. SEM observations of frequency, size and location of accessory foramina in the internal and external furcation areas.

Although the existence of accessory foramina in the furcation area and roots of permanent teeth has been demonstrated, the presence of accessory foramina in furcation areas of primary molars is less certain. This investigation was conducted to determine the presence or absence of accessory foramina in the furcation areas of human primary molars using the scanning electron microscope (SEM). Twenty extracted, carious and noncarious human primary molars were placed in fixative and then mounted in a hard tissue cutting machine: ten teeth were cut transversely 2.0mm coronal to the floor of the pulpal chamber and ten teeth were cut transversely 2.0mm apical to the external furcation. Both the internal and external furcation surfaces of these sectioned molars were debrided with sodium hypochlorite/hydrogen peroxide solutions to remove organic materials, which might obscure visibility of possible foramina and then rinsed in water and dried. The tissues were then prepared for and examined by SEM. Twenty percent of the molars examined by SEM on the internal furcation surface and 50% of the molars examined by SEM on the external furcation surface demonstrated accessory foramina.

An investigation of accessory canals in furcation areas of human primary molars: Part 2. Latex perfusion studies of the internal and external furcation areas to demonstrate accessory canals.

Four classes of accessory canals: "true," "blind," "looping" and "enclosed" canals have been suggested to exist in furcation areas of primary teeth. Although the existence of accessory canals in the furcation areas and roots of permanent teeth has been demonstrated, their presence in furcation areas of primary teeth is uncertain. This investigation was conducted to determine the presence or absence of accessory canals in the furcation areas of human primary molars using a variety of latex perfusion techniques. Twenty extracted, noncarious human primary molars were placed in fixative and then sectioned on a hard tissue cutting machine: ten teeth were cut transversely 2.0 mm coronal to the floor of the pulpal chamber and ten teeth were cut transversely 2.0 mm apical to the external furcation area. The internal and external furcation surfaces of these sectioned molars were debrided with sodium hypochlorite/hydrogen peroxide solutions, rinsed in water and dried to remove organic materials, which might obscure the existence of possible canals. Twenty of these extracted teeth were examined by SEM to detect the possible presence of accessory foramina in the internal and external furcation areas (Part 1). Twenty percent of the molars examined by SEM on the IFA and 50 percent of the molars examined by SEM on the EFA exhibited accessory foramina. Twenty molars were perfused with low viscosity latex using vacuum [negative] pressure (10 molars) and positive pressure (10 molars) to detect the possible existence of the patency and the extent of such accessory canals in the internal and external furcation areas (Part 2).(ABSTRACT TRUNCATED AT 250 WORDS)

An Acquired Factor VIII Inhibitor in a Patient with HIV and HCV: A Case Presentation and Literature Review.

Introduction. Despite its low incidence, acquired factor VIII inhibitor is the most common autoantibody affecting the clotting cascade. The exact mechanism of acquisition remains unclear, but postpartum patients, those with autoimmune conditions or malignancies, and those with exposure to particular drugs appear most susceptible. There have been several case reports describing acquired FVIII inhibitors in patients receiving interferon alpha for HCV treatment and in patients being treated for HIV. To our knowledge, this is the first case of a patient with HCV and HIV who was not actively receiving treatment for either condition. Case Presentation. A 57-year-old Caucasian male with a history of HIV and HCV was admitted to our hospital for a several day history of progressively worsening right thigh bruising and generalized weakness. CTA of the abdominal arteries revealed large bilateral retroperitoneal hematomas. Laboratory studies revealed the presence of a high titer FVIII inhibitor. Conclusion. Our case of a very rare condition highlights the importance of recognizing and understanding the diagnosis of acquired FVIII inhibitor. Laboratory research and clinical data on the role of newer agents are needed in order to better characterize disease pathogenesis, disease associations, genetic markers, and optimal disease management.

p21(WAF1) gene promoter is epigenetically silenced by CTIP2 and SUV39H1.

Mainly regulated at the transcriptional level, the cellular cyclin-dependent kinase inhibitor, CDKN1A/p21(WAF1) (p21), is a major cell cycle regulator of the response to DNA damage, senescence and tumor suppression. Here, we report that COUP-TF-interacting protein 2 (CTIP2), recruited to the p21 gene promoter, silenced p21 gene transcription through interactions with histone deacetylases and methyltransferases. Importantly, treatment with the specific SUV39H1 inhibitor, chaetocin, repressed histone H3 lysine 9 trimethylation at the p21 gene promoter, stimulated p21 gene expression and induced cell cycle arrest. In addition, CTIP2 and SUV39H1 were recruited to the silenced p21 gene promoter to cooperatively inhibit p21 gene transcription. Induction of p21(WAF1) gene upon human immunodeficiency virus 1 (HIV-1) infection benefits viral expression in macrophages. Here, we report that CTIP2 further abolishes Vpr-mediated stimulation of p21, thereby indirectly contributing to HIV-1 latency. Altogether, our results suggest that CTIP2 is a constitutive p21 gene suppressor that cooperates with SUV39H1 and histone methylation to silence the p21 gene transcription.

Isolation and characterization of macrophage phagosomes containing infectious and heat-inactivated Chlamydia psittaci: two phagosomes with different intracellular behaviors.

Infectious Chlamydia psittaci enters macrophages via a cytochalasin B-insensitive pathway in which chlamydia-containing phagosomes do not fuse with lysosomes; heat-inactivated C. psittaci enters macrophages via a route in which phagosomes do fuse with lysosomes. In an attempt to explain these differences, phagosomes containing infectious and heated chlamydiae were isolated from mouse macrophages by a procedure developed to isolate L-cell chlamydial phagosomes by rate zonal centrifugation. Macrophage phagosomes acted similarly to L-cell phagosomes on dextran and discontinuous sucrose gradients and exhibited similar detergent sensitivities. Total proteins of the two phagosomes were compared with each other, L-cell proteins, and surface-labeled proteins from macrophages. Both macrophage phagosome membranes had at least nine proteins with equal sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobilities; some were the same as L-cell phagosome proteins. Each phagosome had at least one protein not seen in the other. Only two phagosome proteins had mobilities equal to macrophage plasma membrane proteins. Macrophage phagosomes containing infectious and heat-inactivated C. psittaci, although created by different entry mechanisms and destined for different intracellular fates, exhibited only a few differences in their proteins.