Five-year follow-up of oral functioning and quality of life in patients with oral cancer with implant-retained mandibular overdentures.

BACKGROUND: The purpose of this prospective study was to assess the quality of life (QOL) and oral functioning of patients with oral cancer up to 5 years after prosthodontic rehabilitation with mandibular implant-retained overdentures. METHODS: Fifty patients who had received implants during ablative surgery were evaluated by standardized questionnaires before and after oncological and prosthetic treatment. RESULTS: In 20 of 24 surviving patients, the dentures were functional after 5 years. In these survivors, oral function remained unchanged during this period. In the 6 patients with concurrent comorbidity, global health and QOL had deteriorated, while in the patients without comorbidity, global health and QOL were very high. Five-year survivors had a higher global health and better oral functioning at the 1-year evaluation than nonsurvivors. CONCLUSION: Oral function and denture satisfaction were high and did not change over time for survivors. Deterioration in overall global health and QOL was associated with concurrent comorbidity.

A colorimetric assay for determination of residual detergent levels in reconstituted membrane protein preparations.

Simple and robust methods for the quantification of residual detergent in purified membrane proteins are not readily available. In this article, solubilization of precipitated dye by detergent is shown to be a facile method for the quantification of residual levels of octaethylene-glycol-mono(n-dodecyl)ether in virosomal influenza vaccine. Dye solubilization starts in the critical micellar concentration range. The method is more sensitive than an existing assay and is highly accurate and precise. The method is applicable to other detergents as well. This method of residual detergent quantification is simple and straightforward and is a useful tool for quality control of subunit vaccines.

Benefits of dental implants installed during ablative tumour surgery in oral cancer patients: a prospective 5-year clinical trial.

OBJECTIVE: This prospective study assessed treatment outcome and patient satisfaction of oral cancer patients with a mandibular overdenture on implants up to 5 years after treatment. MATERIALS AND METHODS: At baseline, 50 consecutive edentulous oral cancer patients, in whom prosthetic problems were expected after oncological treatment, were evaluated by standardized questionnaires and clinical assessments. All implants were installed during ablative tumour surgery in native bone in the interforaminal area. About two-thirds of the patients (n=31) had radiotherapy post-surgery (dose >40 Gy in the interforaminal area). RESULTS: At the 5-year evaluation, 26 patients had passed away and four patients had to be excluded from the analyses, because superstructures were not present, due to persistent local irritation (n=2), loss of three implants (n=1) and the impossibility of making an overdenture related to tumour and oncological surgery-driven anatomical limitations (n=1). In the remaining 20 patients, the prosthesis was still in function (76 implants). During the 5-year follow-up, total 14 implants were lost, 13 in irradiated bone (survival rate 89.4%, dose >40 Gy) and one in non-irradiated bone (survival rate 98.6%). Peri-implant tissues had a healthy appearance and remained healthy over time. Patients were satisfied with their dentures. CONCLUSIONS: It was concluded that oral cancer patients can benefit from implants installed during ablative surgery, with a high survival rate of the implants, a high percentage of rehabilitated patients and a high denture satisfaction up to 5 years after treatment.

Quality of life related to oral function in edentulous head and neck cancer patients posttreatment.

PURPOSE: Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an oral condition unfavorable for prosthodontic rehabilitation. This study assessed the quality of life related to oral function in edentulous head and neck cancer patients following oncology treatment of malignancies in the lower region of the oral cavity. MATERIALS AND METHODS: Patients treated between 1990 and 2000 with surgery and radiotherapy for a squamous cell carcinoma in the oral cavity who were edentulous in the mandible and had been treated with a conventional, non-implant-retained denture received an invitation for a clinical check-up (clinical assessment, questionnaires regarding oral function and quality of life). RESULTS: Sixty-seven of the 84 patients who fulfilled the inclusion criteria were willing to participate in the study. The mean irradiation dosage that these patients had received in the oral region was 61.8 +/- 5.4 Gy. Half of the patients (n=33) were not very satisfied with their prostheses; they wore their mandibular prostheses at most a few hours per day. It was concluded from the clinical assessment that two thirds of the patients (n 4) could benefit from an implant-retained mandibular denture. Analyses of the questionnaires revealed no significant associations between functional assessments, quality of life, and parameters such as size of the primary tumor, location of the primary tumor, and different treatment regimes. Despite cancer treatment, the patients reported a rather good general quality of life. CONCLUSIONS: Sequelae resulting from radiotherapy probably dominate oral function and quality of life after oncology treatment. In two thirds of the patients, improvement of oral function and related quality of life would be expected with the use of an implant-retained mandibular denture.

Cellular gene transfer mediated by influenza virosomes with encapsulated plasmid DNA.

Reconstituted influenza virosomes (virus membrane envelopes) have been used previously to deliver pDNA (plasmid DNA) bound to their external surface to a variety of target cells. Although high transfection efficiencies can be obtained with these complexes in vitro, the virosome-associated DNA is readily accessible to nucleases and could therefore be prone to rapid degradation under in vivo conditions. In the present study, we show a new method for the production of DNA-virosomes resulting in complete protection of the DNA from nucleases. This method relies on the use of the short-chain phospholipid DCPC (dicaproylphosphatidylcholine) for solubilization of the viral membrane. The solubilized viral membrane components are mixed with pDNA and cationic lipid. Reconstitution of the viral envelopes and simultaneous encapsulation of pDNA is achieved by removal of the DCPC from the mixture through dialysis. Analysis by linear sucrose density-gradient centrifugation revealed that protein, phospholipid and pDNA physically associated to particles, which appeared as vesicles with spike proteins inserted in their membranes when analysed by electron microscopy. The DNA-virosomes retained the membrane fusion properties of the native influenza virus. The virosome-associated pDNA was completely protected from degradation by nucleases, providing evidence for the DNA being highly condensed and encapsulated in the lumen of the virosomes. DNA-virosomes, containing reporter gene constructs, transfected a variety of cell lines, with efficiencies approaching 90%. Transfection was completely dependent on the fusogenic properties of the viral spike protein haemagglutinin. Thus, DNA-virosomes prepared by the new procedure are highly efficient vehicles for DNA delivery, offering the advantage of complete DNA protection, which is especially important for future in vivo applications.

Rehabilitation of oral function in head and neck cancer patients after radiotherapy with implant-retained dentures: effects of hyperbaric oxygen therapy.

Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an anatomic and physiological oral condition unfavorable for prosthodontic rehabilitation. The objective of this prospective study was to assess the effect of hyperbaric oxygen therapy on treatment outcome (condition of peri-implant tissues, implant survival, oral functioning and quality of life) of prosthodontic rehabilitation with implant-retained lower dentures in radiated head and neck cancer patients 6 weeks and 1 year after placing the new dentures. The treatment outcome was assessed in a group of 26 head neck cancer patients who were subjected to radiotherapy after tumour surgery. Standardized questionnaires were completed and clinical and radiographic assessments were performed. After randomization, endosseous Brånemark implants were placed in the anterior part of the mandible either under antibiotic prophylaxis (13 patients) or under antibiotic prophylaxis combined with pre and postsurgery hyperbaric oxygen (HBO) treatment (13 patients). In the HBO and non-HBO group eight implants (implant survival 85.2%) and three implants (implant survival 93.9%) were lost, respectively. Peri-implant tissues had a healthy appearance in both groups. Osteoradionecrosis developed in one patient in the HBO group. All patients functioned well with their implant-retained lower denture. The quality of life related to oral functioning and denture satisfaction were improved to a comparable extent in the HBO and non-HBO group. Implant-retained lower dentures can improve the quality of life related to oral functioning and denture satisfaction in head and neck cancer patients. Adjuvant hyperbaric oxygen therapy could not be shown to enhance implant survival in radiated mandibular jaw bone.

Use of a dialyzable short-chain phospholipid for efficient solubilization and reconstitution of influenza virus envelopes.

Virosomes are reconstituted viral envelopes that can serve as vaccines and as vehicles for cellular delivery of various macromolecules. To further advance the use of virosomes, we developed a novel dialysis procedure for the reconstitution of influenza virus membranes that is easily applicable to industrial production and compatible with encapsulation of a variety of compounds. This procedure relies on the use of 1,2-dicaproyl-sn-glycero-3-phosphocholine (DCPC) as a solubilizing agent. DCPC is a short-chain lecithin with detergent-like properties and with a critical micelle concentration of 14 mM. DCPC effectively dissolved the influenza virus membranes after which the nucleocapsids could be removed by ultracentrifugation. The solubilized membrane components were reconstituted either by removal of DCPC by dialysis or by a procedure involving initial dilution of the solubilized membrane components followed by dialysis. Both protocols resulted in removal of 99.9% of DCPC and simultaneous formation of virosomes. Analysis of the virosome preparations by equilibrium sucrose density gradient centrifugation revealed co-migration of phospholipid and protein for virosomes produced by either method. Moreover, both virosome preparations showed morphological and fusogenic characteristics similar to native influenza virus. Size, homogeneity and spike density of the virosomes varied with the two different reconstitution procedures employed. The recovery of viral membrane proteins and phospholipids in the virosomes was found to be higher for the dilution/dialysis procedure than for the simple dialysis protocol. This novel procedure for the production of virosomes is straightforward and robust and allows further exploitation of virosomes as vaccines or as drug delivery vehicles not only in academia, but also in industrial settings.

Semliki Forest virus is an efficient and selective vector for gene delivery in infarcted rat heart.

Gene therapy is emerging as a realistic addition to the therapeutic arsenal in heart failure, but the search for suitable vectors for cardiac transfection is still ongoing. In this study, we explore the applicability of recombinant Semliki Forest virus (SFV) in heart failure. SFV was intracoronarily delivered 2 weeks after induction of myocardial infarction in the rat model for heart failure. Duration of SFV expression was determined, and tissue distribution was studied by histochemical, biochemical, and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses. Expression of SFV-mediated transfection in the heart reached its maximum after 48-72 h and subsided within a week. Intracoronary administration of SFV efficiently transfected the non-infarcted cardiac wall, resulting in high levels of beta-galactosidase (beta-gal) activity (1337 +/- 537 IU/mg) and lacZ RNA in the hearts of all rats, whereas brain, kidney, liver, lung, spleen, and testis were lacZ negative. In conclusion, intracoronarily delivered SFV has a favourable distribution pattern, showing expression of the transgene restricted to the heart.

Mandibulotomy and implant insertion.

BACKGROUND: A mandibulotomy can be necessary to approach a tumor in the oral cavity or oropharynx. The aim of this study was to develop and prospectively evaluate a technique enabling simultaneous performance of a mandibulotomy and insertion of endosseous implants in the same area. METHODS: In five edentulous patients such a procedure was performed. The pilot drilling of the implants was done before performing the mandibulotomy. After tumor resection, reconstruction, and restoration of the continuity of the mandible, the final drilling and insertion of the implants were completed. In total, 20 implants were inserted. All patients received radiation therapy within 6 weeks after surgery. Implant-supported overdentures were fabricated 6 months after irradiation. At regular time intervals, a standardized clinical and radiographic evaluation was performed. RESULTS: No complications with respect to the combination of implant insertion and mandibulotomy were observed either during or after surgery. In addition, no adverse mucosal reactions were observed during the course of radiotherapy, no cases of osteoradionecrosis developed, and no implants were lost. Clinical and radiographic evaluation revealed healthy peri-implant parameters. CONCLUSION: From this study it is concluded that, when following the technique described, a mandibulotomy can be combined safely with the insertion of implants in the ventral part of the edentulous mandible.

Early loading of endosseous implants in the augmented maxilla: a 1-year prospective study.

In 10 patients, 68 endosseous implants were inserted in the augmented edentulous maxilla using a one-stage implant placement technique. Three months before implant insertion, the width and height of the alveolar crest were augmented with autologous bone grafts from the iliac crest. In all cases, the resulting bone volume was sufficient for implant insertion. According to an early loading protocol, the implant-supported overdenture was fabricated 2 months after insertion of the implants. Evaluation was performed according to a standardised protocol immediately and 1 year after fabrication of the prosthetic construction. The protocol included assessment of both clinical (bleeding score, pocket depth, implant mobility) and radiographic (marginal bone level on standardised radiographs) parameters. Three implants in two patients in the upper jaw were lost (survival rate: 95.6%). The peri-implant tissues had a healthy appearance and bone loss was minimal. Overall, the patients were very satisfied with the prosthetic construction. From this preliminary study, it is concluded that in selected cases, early loading of implants may develop into a predictable treatment modality after augmentation of the maxilla.

Increased neutrophil priming and sensitization before commencing cardiopulmonary bypass in cardiac surgical patients.

BACKGROUND: Neutrophil activation is implicated in postoperative complications in patients having cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to determine the temporal fluctuations in the primability of neutrophils in the preoperative, intraoperative, and postoperative periods of CPB, and specifically whether CPB was a primary cause leading to increased neutrophil priming and elastase release. METHODS: Twenty patients undergoing multiple coronary bypass grafting, valve replacement, or both of these procedures were included in this study. Blood samples were taken 1 day before the operation and at several time points during and after the operation. For each sample, blood was divided in vitro into four subgroups: control without priming, priming alone with cytochalasin B (CytoB), priming plus stimulation with platelet-activating factor (PAF), and priming plus stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP). The elastase concentration of all these samples was determined using the enzyme immunoassay. RESULTS: Compared with the controls, CytoB priming increased release of elastase more than 10-fold before CPB, 1.6-fold during CPB, and 1.5-fold at the end of CPB. Further stimulation with PAF or fMLP showed greater increase of elastase than priming alone, with peak values in both found before CPB. This increased neutrophil primability prior to CPB did not differ significantly among patients who had different preoperative disease profiles. CONCLUSIONS: Our data suggest that neutrophil priming occurs early before commencing CPB in cardiac surgical patients, and that CPB is not the primary primer. Anesthesia, surgical trauma, and other events may have been involved in neutrophil priming and sensitization before CPB, which warrants further investigation.

Fusion of alphaviruses with liposomes is a non-leaky process.

It has been reported that low-pH-induced fusion of influenza virus with liposomes results in rapid and extensive release of both low- and high-molecular-weight substances from the liposomes [Günther-Ausborn et al., J. Biol. Chem. 270 (1995) 29279-29285; Shangguan et al., Biochemistry 35 (1996) 4956-4965]. Here, we demonstrate retention of encapsulated water-soluble compounds during fusion of Semliki Forest virus (SFV) or Sindbis virus with liposomes at low pH. Under conditions allowing complete fusion of the liposomes, a limited fluorescence dequenching of liposome-encapsulated calcein was observed, particularly for SFV. Also, radioactively labeled inulin or sucrose were largely retained. Freezing and thawing of the viruses in the absence of sucrose resulted in an enhanced leakiness of fusion. These results support the notion that the alphavirus fusion event per se is non-leaky and may well involve a discrete hemifusion intermediate.