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.

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.

Mutational analysis of the HIV-1 LTR as a promoter of negative sense transcription.

The HIV-1 gene promoter is a bi-directional promoter of transcription. We report the characterization of the negative sense promoter (NSP) by analysis of the effect on negative sense transcription of a series of LTR U3 region substitution mutants. Mutations in the region nt -58 to -183 (positive sense transcription initiation nt +1) reduced transcription to <15% of wild type NSP activity. This region, essential for NSP activity, was designated the core basal promoter. Over expression of NF-kappaB RelA(p65) and LEF-1 increased negative sense expression, as did over expression of H-ras oncogene, consistent with the presence of cognate sequence motifs for NF-kappaB, LEF-1 and RBF. We were also able to confirm that the NSP is a TATA-less promoter inhibited by HIV-1 Tat. Based on our findings, we propose a model for the interaction between the NSP and PSP, and the role of Tat in regulating the interaction.

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.

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.

Transcription program of human herpesvirus 8 (kaposi's sarcoma-associated herpesvirus).

Human herpesvirus 8 (HHV-8), a gammaherpesvirus implicated in Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease, encodes several pathogenically important cellular homologs. To define the HHV-8 transcription program, RNA obtained from latently infected body cavity-based lymphoma 1 cells induced to undergo lytic replication was used to query a custom HHV-8 DNA microarray containing nearly every known viral open reading frame. The patterns of viral gene expression offer insights into the replication and pathogenic strategies of HHV-8.

Long-term virologic and immunologic responses in human immunodeficiency virus type 1-infected children treated with indinavir, zidovudine, and lamivudine.

Virologic and immunologic responses were examined for 33 human immunodeficiency virus (HIV)-infected children who participated for > or = 96 weeks in a phase 1/2 protocol of 16 weeks of indinavir monotherapy, followed by the addition of zidovudine and lamivudine. At week 96, a median increase of 199 CD4+ T cells/microL and a median decrease of 0.74 log(10) HIV RNA copies/mL were observed. The relationship between control of viral replication and CD4) T cell count was examined. Patients were categorized into 3 response groups on the basis of duration and extent of control of viral replication. Of 21 children with a transient decrease in virus load of > or = 0.7 log(10) HIV RNA copies/mL from baseline, 7 experienced sustained increases in CD4+, CD4+ CD45RA+, and CD4+ CD45RO+ T cell counts. CD4+ CD45RA+ (naive) T cells were the major contributor to CD4+ T cell expansion. Continued long-term immunologic benefit may be experienced by a subset of children, despite only transient virologic suppression.

Human herpesvirus 8 cellular immune responses in homosexual men.

Little is known about cellular immunity to human herpesvirus 8 (HHV-8), the virus associated with Kaposi's sarcoma (KS). T cell proliferative responses to purified HHV-8 were measured in homosexual men, a group with elevated HHV-8 seroprevalence and high risk of KS. None of 20 blood donor controls had T cell responses to HHV-8. Among human immunodeficiency virus (HIV)-negative homosexual men, 8 (42%) of 19 HHV-8 seropositive men responded as did 4 (16%) of 25 HHV-8 seronegative men. Among HIV-positive homosexual men, however, none of 21 HHV-8 seropositives had T cell responses to HHV-8, even though most responded to common recall antigens, and 10 had >/=400 CD4 cells/mm3. The results suggest that HHV-8 T cell proliferative responses are common in HIV-negative homosexual men and that HIV infection may be associated with diminished HHV-8 cellular immunity, possibly before there is substantial depletion of CD4 cells. If correct, this could explain why KS occurs relatively early in HIV infection/AIDS.

Telomere dynamics in monkeys: increased cell turnover in macaques infected with chimeric simian-human immunodeficiency viruses.

To address the question of how cell turnover is affected by retroviral infections, we used the telomeric terminal restriction fragments (TRFs) as markers of cell replicative history and measured their length in macaques infected with chimeric simian-human immunodeficiency viruses (SHIVs). The TRF lengths of mononuclear cells in 104 samples, including longitudinal samples from nine cynomolgus and ten pig-tailed macaques infected with SHIV, and in samples from 26 uninfected macaques, were quantitated by an improved method, based on two-dimensional calibration of DNA sizes, pulsed field electrophoresis, and high-resolution Southern blot images. The average TRF lengths of peripheral blood mononuclear cells (PBMCs) from uninfected pig-tailed (14.9+/-1.6 kbp) and cynomolgus (14.1+/-1.8 kbp) macaques were about 3 and 5 kbp longer than those of human infants and 30-year-old adults, respectively. The rate of TRF length shortening in infected pig-tailed macaques was significantly (P = 0.035) higher (2.2-fold) than in uninfected monkeys. The TRFs in SHIV-infected cynomolgus monkeys, which, in general, had lower viral loads than pig-tailed macaques, shortened on average more rapidly (1.6-fold) than in uninfected animals, but the difference was not statistically significant. The TRFs of mononuclear cells from the lymph nodes of two rapidly progressing SHIV-infected macaques that developed AIDS and died also shortened in parallel but somewhat more rapidly than in the PBMCs. These results suggest that the rate of PBMC turnover in macaques could be increased several-fold during infections by immunodeficiency viruses, likely due to immune activation by SHIV antigens.

Rapid telomere shortening in children.

Telomere shortening may reflect the total number of divisions experienced by a somatic cell and is associated with replicative senescence. We found that the average rate of telomere shortening in peripheral blood mononuclear cells (PBMCs) obtained longitudinally from nine different infants during the first 3 years of life (270 bp per year) is more than fourfold higher than in adults and does not correlate with telomerase activity. These results show that the rate of telomere loss changes during ontogeny, suggesting the existence of periods of accelerated cell division. Because human immunodeficiency virus (HIV) preferentially infects actively dividing cells, our observation suggesting accelerated cell division in children may provide an explanation for some of the distinctive pathogenic features of the HIV disease in infants, including higher viral loads and more rapid progression to acquired immunodeficiency syndrome (AIDS).

Long-term telomere dynamics: modest increase of cell turnover in HIV-infected individuals followed for up to 14 years.

To quantify the long-term dynamics of telomere lengths and the effect of HIV infection on lymphocyte turnover rates, we measured in a blinded study longitudinal samples from 6 individuals using a highly accurate method based on two-dimensional calibration of DNA sizes. For two uninfected controls followed 8 and 10 years the average telomeric terminal restriction fragment (TRF) shortening rate in peripheral blood mononuclear cells (PBMCs) was 50 and 60 bp/year, respectively, in agreement with previous measurements of cross-sectional samples. The TRF lengths of PBMCs from two slow progressors followed for 14 years declined by a rate of 120 +/-10 bp/year, i.e. 2-fold higher than the rate of TRF shortening for uninfected individuals. The rate of TRF shortening was higher in CD8 (140 +/-10 bp/year) than in CD4 (100 +/-10 bp/year) cells. The CD8 cell TRFs of the two fast progressors shortened faster (240 +/-10 bp/year) and the rate of CD4 cell TRF shortening in one of the fast progressors was 160 bp/year. These data suggest that HIV infection causes only a modest increase in the lymphocyte turnover which we speculate could be due to chronic activation of the immune system, and may not result in the exhaustion of its regenerative capacity and immunopathogenesis.

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.

Glycocalicin levels in the plasma of HIV+ patients: an indicator of platelet turnover.

Glycocalicin (GC) is the carbohydrate-rich portion of platelet membrane glycoprotein Ib(alpha) that can be cleaved from circulating platelets by proteases. The plasma GC level is an indicator of platelet turnover. Using an ELISA for GC, we assayed the plasma of 20 normal children (age 6 to 13 years), 50 HIV+ children (ages 4 to 18 years), 32 normal adults (ages 21 to 53 years), and 50 HIV+ adults (ages 24 to 66 years). The results were adjusted for individual platelet counts to give GC indexes (GCI). The normal children and the normal adults had significantly different GCI distributions (P = .002). In both normal and HIV+ individuals the GCI decreased with increasing platelet count (-.73 < r < -.34). Twenty-eight percent of the HIV+ children and 28% of the HIV+ adults had elevated GCI values. The majority of these elevated values occurred in patients with platelet counts >100,000/microL. Neither the GCI nor the platelet count was correlated with viral load. The platelet count, however, was weakly correlated with the CD4 count in both children (r = .31) and adults (r = .30) infected with HIV. Also, the CD4 count was weakly and inversely correlated with GCI in HIV+ adults (r = -.34) and in children (r = -.24). We conclude that increased GCI and, by implication, increased platelet turnover is a relatively common feature of advanced HIV disease. Furthermore, GCI may be elevated in HIV+ patients even with a platelet count >100,000/microL, suggesting increased platelet turnover before thrombocytopenia develops.

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.

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.

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.