Predicting Openness of Communication in Families With Hereditary Breast and Ovarian Cancer Syndrome: Natural Language Processing Analysis

BACKGROUND

In health care research, patient-reported opinions are a critical element of personalized medicine and contribute to optimal health care delivery. The importance of integrating natural language processing (NLP) methods to extract patient-reported opinions has been gradually acknowledged over the past years. One form of NLP is sentiment analysis, which extracts and analyses information by detecting feelings (thoughts, emotions, attitudes, etc) behind words. Sentiment analysis has become particularly popular following the rise of digital interactions. However, NLP and sentiment analysis in the context of intrafamilial communication for genetic cancer risk is still unexplored. Due to privacy laws, intrafamilial communication is the main avenue to inform at-risk relatives about the pathogenic variant and the possibility of increased cancer risk.

OBJECTIVE

The study examined the role of sentiment in predicting openness of intrafamilial communication about genetic cancer risk associated with hereditary breast and ovarian cancer (HBOC) syndrome.

METHODS

We used narratives derived from 53 in-depth interviews with individuals from families that harbor pathogenic variants associated with HBOC: first, to quantify openness of communication about cancer risk, and second, to examine the role of sentiment in predicting openness of communication. The interviews were conducted between 2019 and 2021 in Switzerland and South Korea using the same interview guide. We used NLP to extract and quantify textual features to construct a handcrafted lexicon about interpersonal communication of genetic testing results and cancer risk associated with HBOC. Moreover, we examined the role of sentiment in predicting openness of communication using a stepwise linear regression model. To test model accuracy, we used a split-validation set. We measured the performance of the training and testing model using area under the curve, sensitivity, specificity, and root mean square error.

RESULTS

Higher "openness of communication" scores were associated with higher overall net sentiment score of the narrative, higher fear, being single, having nonacademic education, and higher informational support within the family. Our results demonstrate that NLP was highly effective in analyzing unstructured texts from individuals of different cultural and linguistic backgrounds and could also reliably predict a measure of "openness of communication" (area under the curve=0.72) in the context of genetic cancer risk associated with HBOC.

CONCLUSIONS

Our study showed that NLP can facilitate assessment of openness of communication in individuals carrying a pathogenic variant associated with HBOC. Findings provided promising evidence that various features from narratives such as sentiment and fear are important predictors of interpersonal communication and self-disclosure in this context. Our approach is promising and can be expanded in the field of personalized medicine and technology-mediated communication.

Language, Childhood, and Fire: How We Learned to Love Sharing Stories

Stories do not fossilize. Thus, exploring tales shared during prehistory, the longest part of human history inevitably becomes speculative. Nevertheless, various attempts have been made to find a more scientifically valid way into our deep human past of storytelling. Following the social brain hypothesis, we suggest including into the theory of human storytelling more fine-grained and evidence-based findings (from archaeology, the cognitive sciences, and evolutionary psychology) about the manifold exaptation and adaptation, genetic changes, and phenotypic plasticity in the deep human past, which all shaped the emergence of storytelling in hominins. We identify three preconditions for humans sharing stories: first, the long evolution of language in the different taxa as one of the preconditions of ostensive signaling; second, the pivotal role of childhood in the evolution of collaborative intentionality; and third, the role of fireside chats in the rise of elaborative (i.e., narrative) sharing of stories. We propose that humans, albeit perhaps no other hominins learned to understand others through sharing stories, not only as intentional agents, but also as mental ones.

Sentiment Analysis of Children and Youth Literature: Is There a Pollyanna Effect?

If the words of natural human language possess a universal positivity bias, as assumed by Boucher and Osgood’s (1969) famous Pollyanna hypothesis and computationally confirmed for large text corpora in several languages (Dodds et al., 2015), then children and youth literature (CYL) should also show a Pollyanna effect. Here we tested this prediction applying an unsupervised vector space model-based sentiment analysis tool called SentiArt (Jacobs, 2019) to two CYL corpora, one in English (372 books) and one in German (500 books). Pitching our analysis at the sentence level, and assessing semantic as well as lexico-grammatical information, both corpora show the Pollyanna effect and thus add further evidence to the universality hypothesis. The results of our multivariate sentiment analyses provide interesting testable predictions for future scientific studies of literature.

Wattpad as a resource for literary studies. Quantitative and qualitative examples of the importance of digital social reading and readers' comments in the margins

The end of deep reading is a commonplace in public debates, whenever societies talk about youth, books, and the digital age. In contrast to this, we show for the first time and in detail, how intensively young readers write and comment literary texts at an unprecedented scale. We present several analyses of how fiction is transmitted through the social reading platform Wattpad, one of the largest platforms for user-generated stories, including novels, fanfiction, humour, classics, and poetry. By mixed quantitative and qualitative methods and scalable reading we scrutinise texts and comments on Wattpad, what themes are preferred in 13 languages, what role does genre play for readers behaviour, and what kind of emotional engagement is prevalent when young readers share stories. Our results point out the rise of a global reading culture in youth reading besides national preferences for certain topics and genres, patterns of reading engagement, aesthetic values and social interaction. When reading Teen Fiction social-bonding (affective interaction) is prevalent, when reading Classics social-cognitive interaction (collective intelligence) is prevalent. An educational outcome suggests that readers who engage in Teen Fiction learn to read Classics and to judge books not only in direct emotional response to character’s behaviour, but focusing more on contextualised interpretation of the text.

Clinical experience and results with a Rhombic Plate for transoral endoscopically-assisted osteosynthesis of fractures of the condylar neck

The intraoral approach is favoured by many patients and surgeons for the treatment of fractures of the condylar neck, but the limited space offered by this approach can make positioning and fixation of the osteosynthesis plate difficult. A rhombic-shaped plate was designed specifically for use with the intraoral approach, and introduced into our clinical practice in 2012. We present the clinical and functional results in 81 patients with 98 fractures of the condylar neck who we have treated with this technique. Of these six required surgical revision, and ultimately all but two had satisfactory occlusion and mandibular function. Our complication rate of 6/81 (7.4%) compares favourably with those reported elsewhere, and confirms that open reduction and internal fixation of condylar fractures using the Rhombic plate through an intra-oral approach provides good outcomes.

Fixation of fractures of the condylar head of the mandible with a new magnesium-alloy biodegradable cannulated headless bone screw

It is difficult to fix fractures of the condylar head of the mandible. Several techniques have been described which show satisfactory outcomes, but stability can be questionable, and some can cause irritation of the soft tissues. We describe a technique and first results of treating such fractures with resorbable magnesium-based headless bone screws (Magnezix^® 2.7mm CS; Syntellix AG, Hanover, Germany).

Genetic basis for variation in plasma IL-18 levels in persons with chronic hepatitis C virus and human immunodeficiency virus-1 infections

Inflammasomes are multi-protein complexes integrating pathogen-triggered signaling leading to the generation of pro-inflammatory cytokines, including interleukin-18 (IL-18). Hepatitis C virus (HCV) and human immunodeficiency virus-1 (HIV) infections are associated with elevated IL-18, suggesting inflammasome activation. However, there is marked person-to-person variation in the inflammasome response to HCV and HIV. We hypothesized that host genetics may explain this variation. To test this, we analyzed the associations of plasma IL-18 levels and polymorphisms in 10 genes in the inflammasome cascade. 1538 participants with active HIV and/or HCV infection in 3 ancestry groups are included. Samples were genotyped using the Illumina Omni 1-quad and Omni 2.5 arrays. Linear regression analyses were performed to test the association of variants with logIL-18 including HCV and HIV infection status and HIV-RNA, in each ancestry group and then meta-analyzed. Eleven highly correlated SNPs (r2=0.98-1) in the IL18-BCO2 region were significantly associated with logIL-18; Each T allele of rs80011693 confers a decrease of 0.06 log pg/mL of IL-18 after adjusting for covariates (rs80011693; rs111311302 β=-0.06, P-value=2.7×10^-4). In conclusion, genetic variation in IL18 is associated with IL-18 production in response to HIV and HCV infection and may explain variability in the inflammatory outcomes of chronic viral infections.

Is failure of condylar neck osteosynthesis predictable based on orthopantomography?

BACKGROUND

Osteosynthesis failure rates of 11.3% with 1 miniplate, 6.7% with 2 miniplates, and 4.4% with a single Medartis condyle plate were reported in previous studies of our clinic. Current science is still focused on the osteosynthesis material. Besides clinical parameters, conventional radiographs are still the first choice to detect osteosynthesis failures. This study scrutinized several factors assessable in postoperative orthopantomographs which might elevate the risk of osteosynthesis failure.

STUDY DESIGN

A total of 136 patients (22 with osteosynthesis failure, 114 without) with 151 mandibular condyle fractures were included in this study. Eight parameters were assessed in postoperative orthopantomographs.

RESULTS

The best predictor of osteosynthesis failure was a simplified concept of ramus height. In cases of reduced or normal ramus height, the odds of osteosynthesis failure was significantly (P = .000001) reduced to a 10th. Isolated fractures were significantly more error prone (P = .0009).

CONCLUSIONS

Postoperative orthopantomographs depict factors which increase the risk of osteosynthesis failure.

Perfusion culture promotes differentiation of oral keratinocytes in vitro

In order to reconstruct the mucosal lining of the oral cavity tissue engineered autologous mucosa grafts could be of great benefit. In conventional stagnant cultures cells often tend to dedifferentiate. Perfusion culture has been demonstrated to reestablish differentiation in various epithelial cell types. Thus, in secondary cultures of human oral keratinocytes from ten patients conventional stagnant culture versus perfusion culture technique was compared. Proliferation and state of differentiation as expressed morphologically and immunohistochemically were assessed. After 14 days oral keratinocytes in a perfusion culture system tend to be further differentiated. They build up a thicker epithelium (3.4+/-1.0 vs. 2.4+/-0.4 layers), form microridges, express cytokeratins 1, 2, 10, 11, 19 but not 13 in all cells and cytokeratins 5, 6 particularly in cells attached to the carrier membrane. In contrast, oral keratinocytes in stagnant culture do not form microridges and rather express cytokeratins 13, 14, and 19 in mattering amounts.

Immunohistochemical comparison of differentiation markers on paraffin and plastic embedded human bone samples

To assess bone pathologies and bone regeneration immunohistochemistry may provide additional information compared to conventional histology. However, the effectiveness of this technique is limited due to tissue fixation, preparation and embedding. For bone tissue the standard immunohistological procedure includes formalin fixation, followed by decalcification and paraffin embedding. This may lead to a badly preserved trabecular bone structure but allows antibody application. Alternatively, methyl-methacrylate (MMA) resin may be used for embedding, thus circumventing the decalcification procedure. In this study immunohistology of typical bone markers was compared using human bone samples fixed either with alcohol or formalin and further decalcified and embedded in paraffin and decalcified or non decalcified samples embedded in Technovit 9100 New(R). On semi-thin sections immunohistochemistry with bone markers osteocalcin, osteonectin, osteopontin, collagen type I and the cellular markers CD34 and CD68 was performed. Independent of the fixative used, Technovit 9100 New embedded non-decalcified bone yielded a stronger immunostaining for all markers when compared to decalcified bone embedded either in methyl-methacrylate or paraffin. In addition there was a better preservation of the trabecular bone morphology. The immunohistochemical results demonstrate that Technovit 9100 New as a low-temperature acrylic resin embedding method can be favoured over paraffin embedding.

One-stage palate repair improves speech outcome and early maxillary growth in patients with cleft lip and palate

There are several types of palatal surgery; each cleft centre chooses its own technique based on experience and treatment philosophy. The aim of this study was to compare speech outcome and maxillary growth in children with cleft lip and palate deformity after palate repair with either a one-stage or a two- stage procedure and to identify the better treatment protocol. In 24 children, speech outcome was assessed regarding resonance, nasal escape, compensatory articulations, facial grimace, and spontaneous speech. In addition, plaster models of 15 children were compared. In 12 children, a two-stage procedure was performed (group A): at the age of 9-12 months, an intravelar veloplasty for repair of the soft palate, and at the age of 24-36 months a bipedicled flap closure of the hard palate. In 12 children, the same techniques were used in a one-stage procedure, at the age of 9-12 months (group B). The children of group B showed less altered resonance and less nasal emission at 4 years of age compared to the children of group A. At 6 years, the children of group A had improved their speech skills, but they did not equal the results of group B. In the study models of group A at age 6 years, the transverse dimension (anterior and posterior width of the dental arch) was smaller than in the models of group B. The one-stage repair of cleft palate at the age of 9-12 months seems to have a more positive influence on speech development and early maxillary growth than the two-stage procedure.

Free DIEP-flap reconstruction of tumour related defects in head and neck

The free deep inferior epigastric perforator flap (DIEP) is a well-established therapy for plastic reconstruction of the breast or defects of the lower extremity without distinct donor site morbidity. Because of its particular qualities we started to apply the DIEP-flap also in reconstruction of defects in the cranio-maxillofacial area. A series of 10 consecutive patients, who received a DIEP-flap for reconstruction of large soft tissue defects after ablative tumour surgery, was reviewed. Nine of the 10 flaps survived and uneventfully healing was observed in 8 of the 10 flaps. Primary layered closure of the abdominal wall was achieved in all cases and no complications at the donor site were observed. In our experience the DIEP may serve as a well considerable alternative to the rectus abdominis flap and the latissimus dorsi flap for bridging extensive reconstructions in the cranio-maxillofacial region. It offers the possibility for flap elevation simultaneously to the surgical procedures in the head and neck area. A special advantage of the DIEP-flap is the very low donor site morbidity.

Adaptation of myosin heavy chain mRNA expression after implantation of poly(3)hydroxybutyrate scaffolds in rat m. latissimus dorsi

The aim of this study is to identify the synergistic effect between an ectopic bone substitute and surrounding tissues, in this case muscle tissue, which is known to have a considerable potential for adaptation. To describe this effect, changes of myosin heavy chain (MyHC) isoform mRNA content of 12 Wistar-King rats m. latissimus dorsi with implanted poly(3)hydroxybutyrate (PHB) scaffolds were examined after six and 12 weeks. At each time interval six rats were killed and implants and surrounding tissues prepared for genetic evaluation. Eight rats without any implants served as controls. After homogenisation of muscle tissue, RNA was extracted and reverse transcribed. Changes in mRNA content were measured by Real-Time PCR using specific primers for type I MyHC, IIa, IIb and IIx isoforms. The mRNA level of myosin isoform type I of the muscles surrounding the implant was significantly increased (p<0.02) compared to the control group. Further, the studied muscle tissue showed a significant decrease in MyHC isoform IIx mRNA compared to the controls (p<0.02). Implantation of PHB scaffolds into rat m. latissimus dorsi causes an increase of its' content of slow myosin isoforms indicating a synergistic effect between the PHB scaffold and the surrounding muscle tissue.

Cell passage and composition of culture medium effects proliferation and differentiation of human osteoblast-like cells from facial bone

Cells loose their capability to multiply and to differentiate when they are serial subcultivated. However, both, multiplication and differentiation are of utmost importance to obtain sufficient amounts of cells for the translation of tissue regeneration into cell based therapeutic approaches. Thus, for the clinical application more information about ideal culture conditions are necessary. Therefore, aim of this study was to assess culture conditions of human osteoblast-like cells during long-term culture focusing on effects of different culture media and ascorbic acid. Biopsies of maxilla and mandible were obtained from 17 patients to test different cell culture media and from 10 patients to analyse differentiation and proliferation related to number of subcultures and ascorbic acid content. Histochemical and immunhistochemical tests (EZ4U assay, ALP histochemistry, type I collagen immunohistochemistry, osteocalcin Elisa) were performed to determine cell proliferation and differentiation. Opti-MEM with 10% FCS produced statistically significant the highest increase in cell counts. The highest proliferation rate in long-term cultivation was seen in the 4th cell passage. A reciprocal relationship between cell proliferation and differentiation over 5 passages with a turning point in the 4(th) passage was found. An ascorbic acid content of 50 microg/ml triggered an optimal increase in differentiation. For osteoblast-like cells, Opti-MEM with 10% FCS proved to be the best culture medium. After 3 passages there is the highest amount of cells with osteogenic differentiation which is enhanced by the addition of ascorbic acid. This approach is suitable for tissue engineering of bone grafts.

Frontoethmoidal meningoencephalocoele repair in Cambodia: outcomes and cost comparisons

In Cambodia, spina bifida is rare, but frontoethmoidal meningoencephalocoeles (MECs) are common. Mean life expectancy for patients with congenital MECs may be <20 years, but the complex treatment required has not been available in the country until recently. During visits by combined neurosurgical/craniofacial teams from both Germany and France, a method of repair has been developed that is suitable for the local conditions, affordable and has allowed Cambodian surgeons to learn how to successfully treat MECs. The surgical technique and initial results with 30 patients have been described in a previous publication. This paper presents the outcomes of 128 cases and illustrates that it is cost-effective for these patients to be treated in Cambodia.

[Exsudativ proliferative synovialitis of the temporomandibular joint]

A 39-year-old male patient suffered from pain in the right temporo-mandibular-joint (TMJ) region for more than one year particular when chewing. He was suspected of having a parotis gland tumor and was admitted to the ENT Department. Three months prior to admission there was an increasing swelling. MRT contrast enhanced scan proofed a partly cystic partly soft tissue dense tumor in the regions of the masseter and pterygoideus medialis muscles and the cranial parts of the parotic gland. Ultrasound scan confirmed these findings and showed in addition a suspect lymph node at level II. Electroneurography of the facial nerve was without pathology. Biopsies revealed no pathologies. With persisting pain the patient was transferred to the Department of Oral and Maxillofacial Surgery. History and clinical examination revealed: regular use of chewing gum for several years, pain and clicking in the TMJ and use of a dental splint without relief after removal of the wisdom teeth 28 and 38. Special radiographic diagnostics did not show any pathology but the swelling was persisting. Open joint surgery and histology proofed a chronic synovialitis of the TMJ. In the follow-up after 7 months the patient was free of pain and complaints. This case demonstrates the necessity of interdisciplinary collegial communication to optimally treat patients that suffer from pathologies at the borders of the specialised fields in the head and neck region.

Transorale operative Therapie von Kiefergelenkfrakturen mit einer 3D-Platte

AIM

The transoral approach minimizes the risk of damaging the facial nerve. However, stable osteosynthesis with two miniplates at the proximal fragment is often not possible. To achieve a stable fixation also of condylar neck fractures a new delta-shaped plate was developed, which meets the biomechanical demands of this region. This plate was tested in a clinical study.

PATIENTS AND METHODS

In total 11 patients suffering from 13 condyle fractures (Spiessl I: n=2, Spiessl II: n=10, Spiessl III: n=1, 3 bilateral fractures) were treated via a transoral approach and assessed clinically as well as radiologically in the follow-up period. Functional parameters and fracture alignment were assessed.

RESULTS

After 6 months postoperative function had returned to normal with a mouth opening of 42 mm and pro- and laterotrusion of more than 5 mm. Postoperative radiographic controls showed a good fracture alignment in 7 of 8 patients respectively in 6 of 8 cases after 6 months. In 12 of 13 fractures directly postoperative and in 10 of 13 fractures 6 months postoperative, respectively, Towne's view radiographs showed an anatomical correct position. No plate fracture and no bending of plates were observed. Loosening of screws was found in 2 patients during plate removal.

CONCLUSION

The newly developed three-dimensional plate was easy to handle, and a sufficiently stable osteosynthesis of condyle fractures was possible. This plate can be recommended for surgical fracture treatment via a transoral approach omitting extraoral scars and damage to the facial nerve.

Do antiviral CD8+ T cells select hepatitis C virus escape mutants? Analysis in diverse epitopes targeted by human intrahepatic CD8+ T lymphocytes

Hepatitis C virus (HCV) is a variable RNA virus that can readily establish persistent infection. Cellular immune responses are important in the early control of the virus. Evidence from animal models suggests that mutation in epitopes recognized by CD8+ T lymphocytes may play an important role in the establishment of persistence but in human persistent infection, equivalent evidence is lacking. We investigated this by analysing a unique resource: viruses from a set of chronically HCV-infected individuals in whom the CD8+ T-cell responses in liver had previously been accurately mapped. Virus was sequenced in seven individuals at 10 epitopes restricted by 10 human leucocyte antigen (HLA) molecules. Two main patterns emerged: in the majority of epitopes sequenced, no variation was seen. In three epitopes, mutations were identified which were compatible with immune escape as assessed using phylogenetic and/or functional studies. These data suggest that - even where specific intrahepatic T cells are detectable - many epitopes do not undergo mutation in chronic human infection. On the contrary, virus may escape from intrahepatic CD8+ T-cell responses in a 'patchy' manner in certain specific epitopes. Furthermore, longitudinal studies to identify the differences between 'selecting' and 'nonselecting' intrahepatic CD8+ T-cell responses are needed in HCV infection.

Frei modellierbare Hydroxylapatit-Kollagen-Komposite zur Sanierung oss�rer Defekte

AIM

In the following study we evaluated the biological response of a new freely moldable bone substitute in an animal model.

MATERIAL AND METHODS

Critically sized defects were created surgically in the lower jaw of ten adult minipigs. The drill defects were filled with hydroxyapatite collagen paste. After observation periods of 1, 3, 6, 12, and 18 months the mandibles were harvested without wound healing defects for histological evaluation of resorption and bone ingrowth with a sawing and grinding technique.

RESULTS

The result of the remodeling process was a complete degradation of hydroxyapatite collagen implants after 12-18 months with reorganization of vital trabeculae oriented in a mature pattern.

CONCLUSION

The hydroxyapatite collagen cement works as an osteoconductor and shows signs of direct osseointegration and resorption.

Nachweis der Osteokalzinexpression osteoblastärer Zellen mandibulären Ursprungs, wachsend auf Biomaterialien, mittels RT-PCR und SDS-PAGE/Western Blotting

A new approach to addressing difficult tissue reconstructive or replacement problems in the oral cavity is to engineer new tissue by using selective cell transplantation on polymer scaffolds. The current study characterized the osteoblastic nature of adherent mandibular cells on biomaterials, which could have a potential use as scaffolds for tissue engineering strategies. Cells of mandibular origin from one patient were cultivated on three different biomaterials (PepGen P-15 trade mark, Frios Algipore, and OsteoGraf/LD-700) for 7 and 14 days and osteocalcin expression was demonstrated by RT-PCR and SDS-PAGE/Western blotting. In order to explicitly characterize only the adherent cells on the biomaterials, we first separated the biomaterials with adherent cells from the culture plate before trypsinization. We could demonstrate that cell growth of adherent mandibular osteoblast-like cells was significantly higher on biomaterials with an organic component (PepGen P-15 trade mark ) in comparison to Frios Algipore and OsteoGraf/LD-700, respectively. In conclusion, only the explicit study of adherent cells at the gene and protein levels gives information about the osteoconductivity of biomaterials.

[DiGeorge syndrome/velcardiofacial syndrome: oral and maxillofacial surgery]

The DiGeorge syndrome/velocardiofacial syndrome is the most frequent chromosomal microdeletion syndrome. Partial deletion of chromosome 22q11 may lead to symptoms including facial dysmorphy, hypoparathyroidism, thymic aplasia, congenital heart disease, developmental retardation, and disturbance of speech development. According to the literature, 9% of patients have cleft palate, an additional 5% have a submucosal cleft, and a total of 32% show velopharyngeal insufficiency. We studied 64 children with a cleft, or with delayed speech development and a submucosal or occult cleft, for the presence of the 22q11deletion using fluorescent in situ hybridisation. Five patients had the 22q11 deletion. We conclude that patients presenting with nasal speech and additional anomalies should all be studied for the presence of submucosal or occult clefting and for the presence of the DiGeorge syndrome/velocardiofacial syndrome.

Influence of donor age and culture conditions on tissue engineering of mucosa autografts

In oral surgery the transplantation of tissue engineered mucosa is used more frequently. The conventional single cell suspension culture method (SCSM) involves murine feeder cells and foetal calf serum. The explant technique (ET) has been used as alternative culture procedure. Aim was to study the efficacy of the ET and the SCSM without feeder cells to grow primary cultures and to test the effects of donor age, of extracellular matrix proteins (ECMP), and of autogenous serum on cell growth in explant cultures. These factors were assessed in cultures of 58 patients overall. In 48 cultures of 12 patients primary cell growth was compared between the ET and the SCSM. Eighteen of 24 cultures were established with the ET whereas only 3 of 24 were established with the SCSM. To test the influence of donor age on cell multiplication, the proliferation rate (DNA synthesis measured by bromodeoxyuridine uptake) and the overall growth (DNA content) was determined in cultures of five young and five old donors. In cultures from old donors (mean age 56 years) proliferation was lower but more sustained relative to the cultures from the young donors (mean age 25 years). In old donors overall in vitro cell growth was only 2/3 of that in young donors. In cultures of 20 donors the influence on cell adhesion and growth of the ECMP fibronectin and laminin was assessed by planimetry. While ECMP augmented explant adhesion, these substances did not enhance keratinocyte growth significantly. Comparing the influence of autogenous and foetal calf serum on cell growth no differences were observed in all cultures of the six donors. In conclusion, the ET without additional ECMP coating and with autogenous instead of foetal calf serum are now used to culture gingival keratinocytes for tissue engineering mucosa grafts. Consequently xenogenous components are avoided, being a considerable advantage.

[Clinical application of tissue-engineered autologous oral mucosa transplants]

BACKGROUND

Tissue engineering of autogenous oral mucosa is a significant enrichment for various indications in oral and maxillofacial surgery. Besides preprosthetic surgery and prelamination of microvascular fasciocutaneous flaps, interdisciplinary work such as reconstruction procedures in cases of hypospadias and epispadias are the main indications for tissue-engineered oral mucosa.

RESULTS

One main advantage of this technique is the reduction of second surgical procedures. The morbidity is decreased and the quality of life may be significantly increased. The manufacture of tissue-engineered autogenous oral mucosa up to 15 cm(2) requires a small biopsy of oral mucosa (4-8 mm(3)) and 40 ml of autogenous serum.

DISCUSSION

The clinical and morphological long-term follow-up after different surgical procedures with tissue-engineered oral mucosa establishes this technique as an excellent additional tool in oral and maxillofacial surgery.

How to optimize seeding and culturing of human osteoblast-like cells on various biomaterials

The optimization of seeding and culturing of human osteoblast-like cells on three collagen-based biomaterials (bovine, equine and calf collagen membrane) was studied by cell proliferation and cell colonization (scanning electron microscopy) analysis. Osteoblasts of five patients were seeded onto the three biomaterials and two different parameters were varied: the time intervals between initial seeding and adding culture medium (2 h 6 h. 12 h, 24 h) and the seeding concentration (1 x 10(5), 1 x 10(6), 2 x 10(6)cells/ml) of cells onto biomaterials. The results of the study demonstrated that the time interval between seeding osteoblasts and adding culture medium as well as the seeding concentration effects the cell proliferation and the cell colonization. The best proliferation rate was achieved by adding the culture medium 2 h after initial seeding and with a seeding density of 1 x 10(5) cells/ml. Moreover, all three biomaterials resulted in different proliferation rates. The best proliferation rate resulted with the bovine collagen membrane. In conclusion, the examined parameters are very important for the development of the tissue engineering techniques and in a larger perspective also for reconstructive surgery.

Cellular immune responses against hepatitis C virus: the evidence base 2002

Hepatitis C virus (HCV) is an RNA virus which is estimated to persistently infect about 170 million people worldwide. After acute infection, there is an initial period during which long-term outcome is decided. There is strong evidence that the cellular immune responses, involving both CD4+ and CD8+ T lymphocytes, are involved at this stage and it is their effectiveness which determines outcome. What is not understood is what determines their effectiveness. The most important component of this is likely to be some aspect of epitope selection, itself dictated by host MHC. Thus, to understand host immunity to HCV, we need to have a detailed understanding of the peptides involved in T lymphocyte responses. In this review, we discuss the peptide epitopes that have been identified so far, and their potential significance. We relate this to a scheme of host defence which may be useful for understanding natural and vaccine-induced immunity.

Prelaminating the fascial radial forearm flap by using tissue-engineered mucosa: improvement of donor and recipient sites

In reconstructive surgery, prelamination of free flaps using split-thickness skin is an established technique to avoid the creation of a considerable defect at the donor site, for example, in the case of a radial forearm flap. For oral and maxillofacial surgery, this technique is less than optimal for the recipient site because the transferred skin is inadequate to form a lining in the oral cavity. To create mucosa-lined free flaps, prelamination using pieces of split-thickness mucosa has been performed. However, the availability of donor sites for harvesting mucosa is limited. The present study combines a tissue-engineering technique with free flap surgery to create mucosa-lined flaps with the intention of improving the tissue quality at the recipient site and decreasing donor-site morbidity. On five patients undergoing resection of squamous cell carcinoma of the oral cavity, the radial forearm flap was prelaminated with a tissue-engineered mucosa graft to reconstruct intraoral defects. Using 10 x 5 mm biopsies of healthy mucosa, keratinocytes were cultured for 12 days and seeded onto collagen membranes (4.5 x 9 cm). After 3 days, the mucosal keratinocyte collagen membrane was implanted subcutaneously at the left or right lower forearm to prelaminate the fascial radial forearm flap. One week later, resection of the squamous cell carcinoma was performed, and the free fascial radial forearm flap pre- laminated with tissue-engineered mucosa was transplanted into the defect and was microvascularly anastomosed. Resection defects up to a size of 5 x 8 cm were covered. In four patients, the graft healed without complications. In one patient, an abscess developed in the resection cavity without jeopardizing the flap. During the postoperative healing period, the membrane detached and a vulnerable pale-pink, glassy hyperproliferative wound surface was observed. This surface developed into normal-appearing healthy mucosa after 3 to 4 weeks. In the postoperative follow-up period, such functions as mouth opening and closing and speech attested to the success of the tissue-engineering technique for flap prelamination.

A clinical audit on the effect of suction drainage on microvascular anastomosis

INTRODUCTION

There are reports that thrombosis in microsurgically anastomosed vessels occurred after the vessels were drawn into the suction drains.

AIM

To study the effects of suction drainage on microvascular anastomosis.

PATIENTS AND METHODS

The authors compared the proportion of complications in 77 patients who had suction drainage (n=45) or no suction drainage (n=32) with microvascular free flap surgery in the head and neck region. Ultrasonography and Doppler flow ultrasonography were performed on five more patients 3 days after the operation.

RESULTS

There were no significant differences between the two retrospectively evaluated groups for incidence of postoperative complications. Ultrasound in the prospective study group revealed that vessels were neither sucked into the suction drain nor displaced towards the drain.

CONCLUSION

These findings contravened the reports of vessels being sucked into drains and therefore the clinical use of suction drainage in conjunction with microsurgery in the head and neck region is still advocated.

The titanium surface texture effects adherence and growth of human gingival keratinocytes and human maxillar osteoblast-like cells in vitro

The adhesion, orientation and proliferation of human gingival epithelial cells and human maxillar osteoblast-like cells in primary and secondary culture were studied on glossy polished, sandblasted and plasma-sprayed titanium surfaces by scanning electron microscopy and in thin sections. The primary cultured explants of human gingival epithelial cells attached, spread and proliferated on all titanium surfaces with the greatest extension on the polished and the smallest extension on plasma-sprayed surfaces. In secondary suspension cultures of gingival keratinocytes, attachment spreading and growth was only observed on polished and plasma-sprayed surfaces, but not on sandblasted surfaces. Moreover, the attachment of these cells depended on the seeding concentration as well as on the coating with fetal calf serum. Cells on polished surfaces developed an extremely flat cell shape, but on sandblasted and plasma-sprayed surfaces a more cuboidal shape. In contrast human maxillar osteoblasts seeded as secondary suspension cultures attached very well to all three differently textured titanium surfaces and showed identical growth patterns independent of the titanium surface structure. These findings suggest that cell morphology, orientation, proliferation and adhesion of human gingival epithelial cells in primary or secondary culture are dependent on the texture of the titanium surface whereas no such differences were observed for maxillar osteoblast-like cells. In conclusion, the soft tissue integration and response is more influenced by the surface texture than the process of osseointegration.

Sustained dysfunction of antiviral CD8+ T lymphocytes after infection with hepatitis C virus

Hepatitis C virus (HCV) sets up persistent infection in the majority of those exposed. It is likely that, as with other persistent viral infections, the efficacy of T-lymphocyte responses influences long-term outcome. However, little is known about the functional capacity of HCV-specific T-lymphocyte responses induced after acute infection. We investigated this by using major histocompatibility complex class I-peptide tetrameric complexes (tetramers), which allow direct detection of specific CD8+ T lymphocytes ex vivo, independently of function. Here we show that, early after infection, virus-specific CD8+ T lymphocytes detected with a panel of four such tetramers are abnormal in terms of their synthesis of antiviral cytokines and lytic activity. Furthermore, this phenotype is commonly maintained long term, since large sustained populations of HCV-specific CD8+ T lymphocytes were identified, which consistently had very poor antiviral cytokine responses as measured in vitro. Overall, HCV-specific CD8+ T lymphocytes show reduced synthesis of tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) after stimulation with either mitogens or peptides, compared to responses to Epstein-Barr virus and/or cytomegalovirus. This behavior of antiviral CD8+ T lymphocytes induced after HCV infection may contribute to viral persistence through failure to effectively suppress viral replication.