Reconstruction of an extensive midfacial defect using additive manufacturing techniques

Malignant peripheral nerve sheath tumours are extremely rare tumours arising in peripheral nerves. Only 17 cases involving the trigeminal nerve have ever been reported. These tumours have a very poor prognosis and very high rates of recurrence and metastases. Their recommended treatment involves complete tumour resection followed by radiation. This can be problematic in the head and neck region. We present a clinical case involving a 33 year old female patient presenting with a slow growing exophytic mass of the anterior maxilla. Incisional biopsy and subsequent histological examination revealed a diagnosis of a malignant peripheral nerve sheath tumour. Surgical resection involved a complete maxillectomy, rhinectomy, and resection of the upper lip and aspects of the left and right cheeks. Reconstruction of the subsequent defect incorporated the placement of 4 zygomatic oncology implants to aid in retention of a facial prosthesis. These implants, however, were subsequently lost so it was decided to manufacture an anatomical model of the hard tissues via 3D printing. This model was used to design and manufacture a titanium frame (customised implant) for the patient, which was then fixated and secured intra-operatively with 21 cortical screws. A maxillary denture and silicone facial prosthesis were also made to fit onto this frame. This is the first known case where additive manufacturing, via the use of rapid prototyping and 3D printing, was employed to manufacture a facial prosthesis.The South African National Research Foundation and Materialise (Leuven, Belgium).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1532-849X2017-10-31hb2016Maxillo-Facial and Oral SurgeryProsthodontic

Sperm DNA fragmentation : implications in assisted reproductive technologies

Dissertation (PhD)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: Male fertility has for many years been defined in vitro as the ability of sperm to fertilize oocytes and to obtain early cleavage-stage embryos. Spermatozoa comprise of an extraordinary high percentage of polyunsaturated fatty acids in their plasma membrane. Due to an extremely low content of cytoplasm, sperm cells have a particularly low potential to scavenge reactive oxygen species (ROS), and are therefore highly sensitive to oxidative processes, which lead to sperm nucleus DNA damage/fragmentation. Normally, DNA fragmentation occurs in every ejaculate and can be induced by an excessive ROS production of active leukocytes or the spermatozoa themselves. Under distressed conditions, DNA fragmentation may also occur in the testis as a result of oxidative processes in the apoptotic cascade. These DNA fragmentations can be regarded as late signs of programmed cell death (apoptosis). Clinically, DNA fragmentation in spermatozoa results in significantly decreased implantation and pregnancy rates especially in patients with oligo- and/or teratozoospermia. The p-pattern normal sperm morphology has been shown to give poorer fertilization rates in vitro than the g- and n-patterns. In this study there is reported on the significant correlation found between the p-pattern normal sperm morphology and sperm DNA fragmentation as measured with the terminal deoxynucleotidyl transferase-mediated dUDP-biotin end labeling (TUNEL) assay. This finding further explains the lower fertility potential of patients presenting with p-pattern normal sperm morphology. In addition, this study explores the intricate relations between ROS in the semen, DNA fragmentation of the spermatozoa, as measured with the TUNEL assay and the sperm chromatin structure assay (SCSA ), spermatozoa apoptotic status and sperm parameters as measured with a standard semen analysis. Positive correlations were found between ROS and the apoptotic status of the sperm, as well as between sperm with non-fragmented DNA and sperm concentration and percentage motility. The results emphasize the importance of sperm selection especially when the treatment of choice is intracytoplasmic sperm injection (ICSI). An early sign of programmed cell death, also known as apoptosis, is the externalization of phosphatidylserine (PS) from the inner membrane leaflet to the outer leaflet. PS shows a high affinity to Annexin V. Apoptotic spermatozoa are able to fertilize oocytes, but embryo senescence may occur at the time when the paternal genes are activated. In this study there is reported on a novel method whereby spermatozoa can be separated on the basis of their apoptotic status through flow cytometry. Results showed that the normal sperm morphology, according to strict criteria, of the resultant nonapoptotic sperm fraction is significantly higher than that of the apoptotic counterpart. With refinement of this technique, it will be possible in future to use these separated non-apoptotic sperm cells during ICSI for fertilization. From the above it is apparent that the spermatozoon has to play a vital role in the development of the embryo from fertilization to implantation and pregnancy. It is, however, important to note that besides the gametes, there are other critical factors which contribute to a successful in vitro fertilization (IVF) cycle, among these are the in vitro culture conditions. In this regard, this study compared two sequential embryo culture systems. It was found that the more complex medium resulted in better day three embryo quality and a better blastocyst formation rate and pregnancy rate. These findings highlight the importance of a holistic perspective towards the complexity of the factors involved in affecting embryo quality and pregnancy outcome.AFRIKAANSE OPSOMMING: Manlike fertiliteit is vir baie jare gedefinieer as die in vitro vermoë van ‘n spermsel om ‘n eiersel te bevrug om sodoende embrios te verkry. Die spermsel se plasmamembraan bestaan uit ‘n hoë persentasie poli-onversadigde vetsure. As gevolg van die klein hoeveelhede sitoplasma van die spermsel het dit ‘n beperkte weerstand teen reaktiewe suurstof spesies (ROS) en is gevolglik baie sensitief vir oksidasie. Oksidasie lei tot DNS skade/fragmentasie. DNS fragmentasie kom in spermselle van alle ejakulate voor en is gewoonlik die gevolg van ROS produksie deur die leukosiete in die semen of vanaf die spermselle self. Onder sekere omstandighede kan DNS fragmentasie ook voorkom in die testis waar dit deel vorm van apoptose. Hierdie tipe DNS skade word gesien as laat tekens van geprogrammeerde seldood (apoptose). In oligo- en/of teratozoospermiese mans lei DNS fragmentasie tot verlaagde implantasie- en swangerskapssyfers. Die p-patroon normale sperm morfologie groep gee laer in vitro bevrugting en swangerskapsyfers as die g- en n-patrone. In hierdie studie doen ons verslag oor die statisties betekenisvolle korrelasie wat gevind is tussen die p-patroon normale sperm morfologie en DNS fragmentasie soos gemeet met die ‘terminal deoxynucleotidyl transferase-mediated dUDP-biotin end labeling’ of te wel TUNEL toets. Hierdie bevinding is ‘n verdere verklaring vir die laer fertiliteits potensiaal van pasiënte wat voordoen met p-patroon sperm morfologie. ‘n Verdere doel van die studie was om die moontlike verband tussen ROS in die semen, spermatozoa DNS fragmentasie, apoptotiese status van die sperms en die motiliteits parameters van die spermatozoa te bepaal. ‘n Positiewe korrelasie is gevind tussen ROS en sperm apoptotiese status. Sperms met ongeframenteerde DNS is ook positief gekorreleer met sperm konsentrasie en motiliteit. Die resultate beklemtoon die belangrikheid van spermseleksie veral in pasiënte waar die keuse van behandeling intrasitoplasmiese sperm inspuiting (ICSI) is. ‘n Vroeë teken van apoptose is die eksternalisering van ‘phosphatidylserine’ (PS) vanaf die interne oppervlakte van die plasmamembraan na die eksterne oppervlak. PS het ‘n hoë affiniteit vir Annexin V. Apoptotiese sperms het die vermoë om ‘n oösiet te bevrug, maar kan lei tot die staking van embrio deling wanneer die vaderlike gene ‘n rol begin speel in embrio ontwikkeling. In hierdie studie het ons ‘n nuwe metode ontwikkel waarvolgens die spermatozoa in die ejakulaat op grond van hul apoptotiese status geskei kan word in apoptotiese en nie-apoptotiese fraksies. Die normale sperm morfologie van die nie-apoptotiese fraksie is betekenisvol beter as dié van die apoptotiese fraksie. Verdere verfyning van die tegniek kan daartoe lei dat dit in die toekoms toegepas kan word om vir nie-apoptotiese sperms te selekteer veral voor die uitvoering van ICSI. Uit die bogenoemde is dit duidelik dat die spermsel ‘n baie belangrike rol in die ontwikkeling van ‘n embrio, vanaf bevrugting tot implantasie en swangerskap, speel. Dit is egter ook belangrik om in gedagte te hou dat daar ander bydraende faktore tot ‘n suksesvolle in vitro swangerskap is, soos laboratorium toestande en embrio kultuursisteem. Om hierdie rede is daar ook twee kultuurmedia in hierdie studie vergelyk. Daar is bevind dat die meer komplekse medium beter kwaliteit embrios op dag drie lewer, asook meer blastosiste en ‘n hoër swangerskapsyfer. Dit is dus duidelik dat dit uiters belangrik is om ‘n holistiese perspektief te hê op die komplekse faktore wat ‘n invloed mag hê op bevrugting, embrio kwaliteit asook die swangerskapsyfer

Clinical aspects of a 2.0-mm locking plate system for mandibular fracture surgery

PURPOSE: The use of a 2.0-mm locking plate system was evaluated in mandibular surgery. PATIENTS AND METHODS: 53 patients (42 male, 11 female) with a total of 56 mandibular fractures were treated with a 2.0-mm mini-locking-plate system and retrospectively examined. Gender, age, cause of fracture, surgical access, classification of fractures, osteosynthesis, postsurgical findings and complications were evaluated. RESULTS: Assault in male patients (mean age 31) was the most common aetiological factor. Fractures in women (mean age 43 years) mostly occurred due to falls. Mandibular angle fractures were the most common and this anatomical site also presented the highest complication rate. Only 6% of patients had minor occlusal disturbance postoperatively, and minor complications (infections and dehiscence) occurred in 14%of patients in this study. Major complications only occurred in one patient included in the study (1.9%). Risk factors for the development of complications in this series were a history of alcohol or tobacco use, mandibular angle fractures, associated facial fractures, presurgical occlusal disturbance and concomitant dental infections. Surgical access to the fracture and the interval from injury to surgery was not associated with the development of complications. CONCLUSIONS: The use of a 2.0-mm locking plate system with its advantages of improved handling characteristics, increased stability, shorter surgical time and the preservation of bony perfusion is a viable alternative to conventional miniplates in the management of mandibular fractures