76 research outputs found
Head and neck cancer in the elderly: a retrospective study over 10 years (1999 - 2008)
INTRODUCTION: Treatment of elderly patients is in many ways different from that for younger ones. The aim of the present study was to identify the particular characteristics and needs of elderly patients suffering from head and neck cancer. From these patterns, considerations for this special group can be deduced. Patients and Material The subjects for this study consisted of 376 patients suffering from head and neck cancer that were treated between 1999 and 2008, 99 (26.3.%) of whom were older than 70 years and were evaluated retrospectively concerning smoking/alcohol abuse, ASA status, kind of malignant neoplasm, localization and treatment. RESULTS: The male-female ratio was 53:46, and mean age, 79 years (71 - 98). Out of 95 patients with a squamous cell carcinoma, 4 patients had a verrucous form. Out of 99 patients, 26 had a maxillary carcinoma and 12 patients had experienced previous non-head-and-neck cancer. An ASA score of 2 or 3 was found in 86 of the patients. CONCLUSION: The group of patients with head and neck cancer who were older than 70 years was characterized by a higher portion of female patients, a higher number of maxillary carcinomas, and a higher prevalence of previous second cancer. Making decisions in cancer therapy for elderly patients is challenging. Patients suffering from operable head and neck cancer should be treated with curative intent and with regard to quality of life if a careful assessment of comorbidities is performed preoperatively
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Adaptive changes in HIV-1 subtype C proteins during early infection are driven by changes in HLA-associated immune pressure
It is unresolved whether recently transmitted human immunodeficiency viruses (HIV) have genetic features that specifically favour their transmissibility. To identify potential "transmission signatures", we compared 20 full-length HIV-1 subtype C genomes from primary infections, with 66 sampled from ethnically and geographically matched individuals with chronic infections. Controlling for recombination and phylogenetic relatedness, we identified 39 sites at which amino acid frequency spectra differed significantly between groups. These sites were predominantly located within Env, Pol and Gag (14/39, 9/39 and 6/39 respectively) and were significantly clustered (33/39) within known immunoreactive peptides. Within 6 months of infection, we detected reversion-to-consensus mutations at 14 sites and potential CTL escape mutations at seven. Here we provide evidence that frequent reversion mutations probably allows the virus to recover replicative fitness which, together with immune escape driven by the HLA alleles of the new hosts, differentiate sequences from chronic infections from those sampled shortly after transmission
Late term tolerance in head neck cancer patients irradiated in the IMRT era
BACKGROUND: The aim was to quantify severe transient and persisting late term effects in our single institution head neck cancer (HNC) cohort treated with curatively intended intensity modulated radiation therapy (IMRT). Hypothesis was if a 2-year follow up (FU) is sufficient to estimate the long term tolerance in HNC irradiated in the IMRT era. METHODS: Between 01/2002-8/2012, 707/1211 (58%) consecutively treated IMRT patients met the inclusion criteria of a FU time >12 months and loco-regional disease control (LRC). 45% presented with loco-regionally advanced disease; 55% were referred for curative definitive IMRT (66Gy-72Gy in 30--35 fractions), 45% underwent postoperative IMRT (60-66Gy in 30--33 fractions). Systemic concomitant therapy was administered in 85%. Highly consistent treatment procedures were performed with respect to contouring processes, dose constraints, radiation schedules, and the use of systemic therapy. Grade 3/4 late term effects were prospectively assessed and analyzed with respect to subgroups at particular risk for specific late effects. RESULTS: Mean/median FU of the cohort was 41/35 months (15--124). 13% of the patients (92/707) experienced any grade 3/4 late effects (101 events in 92/707 patients), 81% in the first 12 months after radiation. 4% of all developed persisting late grade 3/4 effects (25 events in 25/707 patients). CONCLUSIONS: IMRT led to a high late term tolerance in loco-regionally disease free HNC patients. The onset of any G3/4 effects showed a plateau at 2 years. The question of the cervical vessel tolerance in disease free long time survivors is still open and currently under evaluation at our institution
Intra- and Inter-clade Cross-reactivity by HIV-1 Gag Specific T-Cells Reveals Exclusive and Commonly Targeted Regions: Implications for Current Vaccine Trials
The genetic diversity of HIV-1 across the globe is a major challenge for developing an HIV vaccine. To facilitate immunogen design, it is important to characterize clusters of commonly targeted T-cell epitopes across different HIV clades. To address this, we examined 39 HIV-1 clade C infected individuals for IFN-γ Gag-specific T-cell responses using five sets of overlapping peptides, two sets matching clade C vaccine candidates derived from strains from South Africa and China, and three peptide sets corresponding to consensus clades A, B, and D sequences. The magnitude and breadth of T-cell responses against the two clade C peptide sets did not differ, however clade C peptides were preferentially recognized compared to the other peptide sets. A total of 84 peptides were recognized, of which 19 were exclusively from clade C, 8 exclusively from clade B, one peptide each from A and D and 17 were commonly recognized by clade A, B, C and D. The entropy of the exclusively recognized peptides was significantly higher than that of commonly recognized peptides (p = 0.0128) and the median peptide processing scores were significantly higher for the peptide variants recognized versus those not recognized (p = 0.0001). Consistent with these results, the predicted Major Histocompatibility Complex Class I IC50 values were significantly lower for the recognized peptide variants compared to those not recognized in the ELISPOT assay (p<0.0001), suggesting that peptide variation between clades, resulting in lack of cross-clade recognition, has been shaped by host immune selection pressure. Overall, our study shows that clade C infected individuals recognize clade C peptides with greater frequency and higher magnitude than other clades, and that a selection of highly conserved epitope regions within Gag are commonly recognized and give rise to cross-clade reactivities
Feasibility of Sentinel Node Biopsy in Head and Neck Melanoma Using a Hybrid Radioactive and Fluorescent Tracer
This study was designed to examine the feasibility of combining lymphoscintigraphy and intraoperative sentinel node identification in patients with head and neck melanoma by using a hybrid protein colloid that is both radioactive and fluorescent. Eleven patients scheduled for sentinel node biopsy in the head and neck region were studied. Approximately 5 h before surgery, the hybrid nanocolloid labeled with indocyanine green (ICG) and technetium-99m ((99m)Tc) was injected intradermally in four deposits around the scar of the primary melanoma excision. Subsequent lymphoscintigraphy and single photon emission computed tomography with computed tomography (SPECT/CT) were performed to identify the sentinel nodes preoperatively. In the operating room, patent blue dye was injected in 7 of the 11 patients. Intraoperatively, sentinel nodes were acoustically localized with a gamma ray detection probe and visualized by using patent blue dye and/or fluorescence-based tracing with a dedicated near-infrared light camera. A portable gamma camera was used before and after sentinel node excision to confirm excision of all sentinel nodes. A total of 27 sentinel nodes were preoperatively identified on the lymphoscintigraphy and SPECT/CT images. All sentinel nodes could be localized intraoperatively. In the seven patients in whom blue dye was used, 43% of the sentinel nodes stained blue, whereas all were fluorescent. The portable gamma camera identified additional sentinel nodes in two patients. Ex vivo, all radioactive lymph nodes were fluorescent and vice versa, indicating the stability of the hybrid tracer. ICG-(99m)Tc-nanocolloid allows for preoperative sentinel node visualization and concomitant intraoperative radio- and fluorescence guidance to the same sentinel nodes in head and neck melanoma patient
Nanocolloidal albumin-IRDye 800CW: a near-infrared fluorescent tracer with optimal retention in the sentinel lymph node
Purpose: At present, the only approved fluorescent tracer for clinical near-infrared fluorescence-guided sentinel node (SN) detection is indocyanine green (ICG), but the use of this tracer is limited due to its poor retention in the SN resulting in the detection of higher tier nodes. We describe the development and characterization of a next-generation fluorescent tracer, nanocolloidal albumin-IRDye 800CW that has optimal properties for clinical SN detection Methods: The fluorescent dye IRDye 800CW was covalently coupled to colloidal human serum albumin (HSA) particles present in the labelling kit Nanocoll in a manner compliant with current Good Manufacturing Practice. Characterization of nanocolloidal albumin-IRDye 800CW included determination of conjugation efficiency, purity, stability and particle size. Quantum yield was determined in serum and compared to that of ICG. For in vivo evaluation a lymphogenic metastatic tumour model in rabbits was used. Fluorescence imaging was performed directly after peritumoral injection of nanocolloidal albumin-IRDye 800CW or the reference ICG/HSA (i.e. ICG mixed with HSA), and was repeated after 24 h, after which fluorescent lymph nodes were excised. Results: Conjugation of IRDye 800CW to nanocolloidal albumin was always about 50% efficient and resulted in a stable and pure product without affecting the particle size of the nanocolloidal albumin. The quantum yield of nanocolloidal albumin-IRDye 800CW was similar to that of ICG. In vivo evaluation revealed noninvasive detection of the SN within 5 min of injection of either nanocolloidal albumin-IRDye 800CW or ICG/HSA. No decrease in the fluorescence signal from SN was observed 24 h after injection of the nanocolloidal albumin-IRDye 800CW, while a strong decrease or complete disappearance of the fluorescence signal was seen 24 h after injection of ICG/HSA. Fluorescence-guided SN biopsy was very easy. Conclusion: Nanocolloidal albumin-IRDye 800CW is a promising fluorescent tracer with optimal kinetic features for SN detection. © The Author(s) 2012
Hardness Evaluation of Porous Hydroxyapatite Coating
The extensive use of appropriate coatings to improve wear resistance, friction coefficient, electrical properties, corrosion resistance and biomedical application has stimulated a growing interest in their mechanical properties and especially hardness testing that is routinely used for coating evaluation. In this study Jönsson and Hogmark model is applied for the porous hydroxyapatite produced by plasma spraying on Ti6A14V substrate. Firstly, the effect of indentation load on hardness values of coating and substrate are studied. The modified Jönsson and Hogmark model is used to explain the composite hardness behavior and the effect of coating porosity
Rapid, complex adaption of transmitted HIV-1 full-length genomes in subtype C-infected individuals with differing disease progression.
CAPRISA 2013.Objective(s): There is limited information on full-length genome sequences and the
early evolution of transmitted HIV-1 subtype C viruses, which constitute the majority of
viruses spread in Africa. The purpose of this study was to characterize the earliest
changes across the genome of subtype C viruses following transmission, to better
understand early control of viremia.
Design: We derived the near full-length genome sequence responsible for clinical
infection from five HIV subtype C-infected individuals with different disease progression
profiles and tracked adaptation to immune responses in the first 6 months
of infection.
Methods: Near full-length genomes were generated by single genome amplification
and direct sequencing. Sequences were analyzed for amino acid mutations associated
with cytotoxic T lymphocyte (CTL) or antibody-mediated immune pressure, and for
reversion.
Results: Fifty-five sequence changes associated with adaptation to the new host were
identified, with 38% attributed to CTL pressure, 35% to antibody pressure, 16% to
reversions and the remainder were unclassified. Mutations in CTL epitopes were most
frequent in the first 5 weeks of infection, with the frequency declining over time with the
decline in viral load. CTL escape predominantly occurred in nef, followed by pol and
env. Shuffling/toggling of mutations was identified in 81% of CTL epitopes, with only
7% reaching fixation within the 6-month period.
Conclusion: There was rapid virus adaptation following transmission, predominantly
driven by CTL pressure, with most changes occurring during high viremia. Rapid escape
and complex escape pathways provide further challenges for vaccine protection
Timing Constraints of In Vivo Gag Mutations during Primary HIV-1 Subtype C Infection
Background: Aiming to answer the broad question “When does mutation occur?” this study examined the time of appearance, dominance, and completeness of in vivo Gag mutations in primary HIV-1 subtype C infection. Methods: A primary HIV-1C infection cohort comprised of 8 acutely and 34 recently infected subjects were followed frequently up to 500 days post-seroconversion (p/s). Gag mutations were analyzed by employing single-genome amplification and direct sequencing. Gag mutations were determined in relation to the estimated time of seroconversion. Time of appearance, dominance, and completeness was compared for different types of in vivo Gag mutations. Results: Reverse mutations to the wild type appeared at a median (IQR) of 62 (44;139) days p/s, while escape mutations from the wild type appeared at 234 (169;326) days p/s (p<0.001). Within the subset of mutations that became dominant, reverse and escape mutations appeared at 54 (30;78) days p/s and 104 (47;198) days p/s, respectively (p<0.001). Among the mutations that reached completeness, reverse and escape mutations appeared at 54 (30;78) days p/s and 90 (44;196) days p/s, respectively (p = 0.006). Time of dominance for reverse mutations to and escape mutations from the wild type was 58 (44;105) days p/s and 219 (90;326) days p/s, respectively (p<0.001). Time of completeness for reverse and escape mutations was 152 (100;176) days p/s and 243 (101;370) days p/s, respectively (p = 0.001). Fitting a Cox proportional hazards model with frailties confirmed a significantly earlier time of appearance (hazard ratio (HR): 2.6; 95% CI: 2.3–3.0), dominance (4.8 (3.4–6.8)), and completeness (3.6 (2.3–5.5)) of reverse mutations to the wild type Gag than escape mutations from the wild type. Some complex mutational pathways in Gag included sequential series of reversions and escapes. Conclusions: The study identified the timing of different types of in vivo Gag mutations in primary HIV-1 subtype C infection in relation to the estimated time of seroconversion. Overall, the in vivo reverse mutations to the wild type occurred significantly earlier than escape mutations from the wild type. This shorter time to incidence of reverse mutations remained in the subsets of in vivo Gag mutations that reached dominance or completeness
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