Formation and photocatalytic decomposition of a pellicle on anatase surfaces.

The acquired dental pellicle plays a critical role in the adhesion and detachment of dental plaque bacteria. It has been reported that titanium dioxide biomaterials decompose single-protein films by photocatalysis. However, it is not known whether this can also be achieved with complex structured pellicle films. This in vitro study investigated in real-time the formation and photocatalytic decomposition of human pellicle at anatase-saliva interfaces. Nanostructured polycrystalline anatase layers were deposited on titanium-coated quartz crystals by magnetron-sputtering, serving as a model for titanium implant surfaces. The quartz crystals were used as acoustic sensors in a quartz-crystal microbalance (QCM) system with dissipation. In situ UV irradiation of pellicle-covered anatase caused a statistically significant decrease of the adsorbed salivary mass. In contrast, photocatalytic decomposition of pellicle could not be observed on reference titanium surfaces. Wettability characterization revealed superhydrophilicity of anatase upon UV irradiation, whereas titanium was unaffected. XPS measurements provide further information concerning the decomposition of the salivary films. The results suggest that the photocatalytic activity of polycrystalline anatase-modified biomaterial surfaces is able to decompose complex structured macromolecular pellicle films. Therefore, this study opens the way to surface modifications supporting therapeutic approaches of biofilm removal.

The prevalence of radiologic TMJ findings and self-reported orofacial pain in a patient group wearing implant dentures.

PURPOSE: This study had a twofold aim: first, to gather knowledge about the prevalence of radiologic signs of temporomandibular joint osteoarthritis (TMJ-OA) and possible risk factors in patients who had worn an implant prosthesis for between 2.5 and 10 years; and second, to investigate the diagnostic value of radiologic TMJ-OA signs for orofacial pain in a non-temporomandibular disorders group. MATERIALS AND METHODS: Two hundred thirty patients (134 women, 96 men) answered a questionnaire regarding orofacial pain. In mean, they were 64 years old and wore 98 fixed and 132 removable implant dentures. The effect of age, gender, state of the dentition, time span after prosthesis placement, parafunction, and TMJ sounds on radiologic TMJ-OA signs was estimated through multiple logistic regression. The predictive values were calculated to assess the diagnostic value of severe TMJ-OA signs to predict orofacial pain. RESULTS: Prevalence of TMJ-OA signs was 70% for flattening, 23% for osteophytes, and 24% for erosion. Some effect on radiologic TMJ-OA signs of gender and state of the dentition was found. The predictive values for orofacial pain from radiologic TMJ-OA ranged from 0.22 to 0.81. CONCLUSION: Radiologic signs of TMJ-OA were common findings. The study gave no indication that long-term wearing of an implant prosthesis has a negative effect on TMJ-OA. It was not possible to predict orofacial pain from radiologic TMJ-OA signs.

Intergeneric poliovirus recombinants for the treatment of malignant glioma.

Poliovirus neuropathogenicity depends on sequences within the 5' nontranslated region of the virus. Exchange of the poliovirus internal ribosomal entry site with its counterpart from human rhinovirus type 2 resulted in attenuation of neurovirulence in primates. Despite deficient virus propagation in cells of neuronal origin, nonpathogenic polio recombinants retain excellent growth characteristics in cell lines derived from glial neoplasms. Susceptibility of malignant glioma cells to poliovirus may be mediated by expression of a poliovirus receptor, CD155, in glial neoplasms. Intergeneric polio recombinants with heterologous internal ribosomal entry site elements unfolded strong oncolytic potential against experimentally induced gliomas in athymic mice. Our observations suggest that highly attenuated poliovirus recombinants may have applicability as biotherapeutic antineoplastic agents.

New chimaeric hepatitis B virus core particles carrying hantavirus (serotype Puumala) epitopes: immunogenicity and protection against virus challenge.

Virus-like particles generated by the heterologous expression of virus structural proteins are able to potentiate the immunogenicity of foreign epitopes presented on their surface. In recent years epitopes of various origin have been inserted into the core antigen of hepatitis B virus (HBV) allowing the formation of chimaeric HBV core particles. Chimaeric core particles carrying the 45 N-terminal amino acids of the Puumala hantavirus nucleocapsid protein induced protective immunity in bank voles, the natural host of this hantavirus. Particles applied in the absence of adjuvant are still immunogenic and partially protective in bank voles. Although a C-terminally truncated core antigen of HBV (HBcAg delta) tolerates the insertion of extended foreign sequences, for the construction of multivalent vaccines the limited insertion capacity is still a critical factor. Recently, we have described a new system for generating HBV 'mosaic particles' in an Escherichia coli suppressor strain based on a readthrough mechanism on a stop linker located in front of the insert. Those mosaic particles are built up by both HBcAg delta and the HBcAg delta/Puumala nucleocapsid readthrough protein. The particles formed presented the 114 amino acid (aa) long hantavirus sequence, at least in part, on their surface and induced antibodies against the hantavirus sequence in bank voles. Variants of the stop linker still allowed the formation of mosaic particles demonstrating that stop codon suppression alone is sufficient for the packaging of longer foreign sequences in mosaic particles. Another approach to increase the insertion capacity is based on the simultaneous insertion of different Puumala nucleocapsid protein sequences (aa 1-45 and aa 75-119) into two different positions (aa 78 and behind aa 144) of a single HBcAg molecule. The data presented are of high relevance for the generation of multivalent vaccines requiring a high insertion capacity for foreign sequences.

Characterization of potential insertion sites in the core antigen of hepatitis B virus by the use of a short-sized model epitope.

Core particles of hepatitis B virus (HBV) are able to improve the immunogenicity of foreign sequences exposed on the particle surface. The insertion site in the core antigen of HBV (HBcAg) determines the surface presentation and thus the immunogenicity of the foreign sequence. For direct comparison of the value of potential insertion sites in the core antigen, we constructed vectors allowing insertions of a model marker epitope DPAFR. This epitope was inserted at the N-terminus, the c/e1 loop, behind amino acid (aa) 144 and behind aa 183 (DPAF only). In addition, we generated a mosaic construct allowing the co-expression of HBcAg and a HBcAg/DPAFR fusion protein due to a suppressor tRNA-mediated readthrough mechanism. All 6 constructs allowed the formation of chimaeric or mosaic core-like particles. Western blot analyses and a direct ELISA demonstrated the presence of the DPAFR sequence in the chimaeric and mosaic particles. Competitive ELISA and immune electron-microscopic data suggested the c/e1 loop as the insertion site of choice for presenting foreign sequences on the surface of chimaeric HBV core particles. However, the N-terminal fusion also allowed partial surface exposure of the DPAFR motif. In contrast, in particles of constructs carrying the DPAFR insert at aa position 144 or 183, respectively, the epitope seemed not to be surface accessible.

The mobility outcome for amputees with rheumatoid arthritis is poor.

This study examines the reasons for amputation of the lower limb in 11 patients with RA. The reasons for amputation were ischaemia due to peripheral vascular disease; rheumatoid vasculitis; or complications of knee arthroplasty. Delayed healing was common in patients on steroid therapy. The patients had difficulty donning and doffing their prostheses due to poor hand function and impaired agility. Walking training and rehabilitation were slow and tended to precipitate a generalized flare-up of disease activity. Rheumatoid nodules developed on pressure points between stump and socket. Despite these problems the majority of patients preferred to wear a prosthesis for help in transferring in and out of the wheelchair, to complete their appearance and for limited mobility. Most found using an electric powered indoor wheelchair helped maintain their independence.

Racquet sports--patterns of injury presenting to a sports injury clinic.

In an 8-year retrospective study, 631 injuries due to the racquet sports of squash (59%), tennis (21%) and badminton (20%) were seen in a sports injury clinic, males predominating (58 to 66%). The proportion of squash injuries was higher than expected and probably relates to higher physical stress and risk of contact in this sport. Also they occurred mainly in persons over 25 years (59%) i.e. the reverse for sport in general. Acute traumatic injuries were seen especially in squash players, a majority affecting the knee, lumbar region, muscles and ankle. Tennis injuries differed most with lateral epicondylitis, patello-femoral pain and lumbar disc prolapse being relatively common. The badminton injury pattern overlapped the others. Lower limb injuries predominated in all three. Detailed assessment of 106 cases showed many to be new, infrequent, social players. Poor warm-up was a common factor in new and established players. The importance of these findings is discussed.

Thermographic diagnosis in athletes with patellofemoral arthralgia.

Pain in front of the knee is common in athletes and is often called patellofemoral arthralgia, but it is difficult to prove that the pain arises in that joint. Thermograms of 30 athletes clinically considered to have patellofemoral arthralgia were compared with those of a similar number of unaffected athletes matched for age and sex. A comparison was also made with thermograms of two older groups of 30 patients with knee involvement from either rheumatoid arthritis or osteoarthritis. Twenty-eight of the athletes with patellofemoral arthralgia had a diagnostic pattern on thermography. The anterior knee view showed a rise in temperature on the medial side of the patella and the medialis knee view showed that this temperature rise radiated from the patellar insertion of the vastus medialis into the muscle itself. The possible aetiological role of quadriceps muscle imbalance in athletes with patellofemoral arthralgia is discussed in relation to these findings.

Spina bifida occulta: lesion or anomaly?

Failure of fusion of the posterior arches of the lumbosacral spine above S3 was sought on frontal radiographs of 653 patients attending an accident and emergency (A & E) department. The patients were aged from 2 months to 98 years and represent all those with relevant information discharged as A & E outpatients over a 2-year period. Presenting complaints of backache or enuresis and inadequate radiographs were excluded. Spina bifida occulta was diagnosed in 22% of the whole group. The incidence was much higher in those below the age of 40 years (29.2%) compared with those above (9.8%). The overall age-adjusted incidence was 17.3%. Our study is an attempt to judge the off-the-street' prevalence of spina bifida occulta. It supports the notion that spina bifida occulta is a common anomaly, of no clinical significance on its own.

The diagnosis of stress fractures in athletes.

Eighteen patients with shin pain that was clinically considered to be caused by a stress fracture of the tibia or fibula underwent radiological, thermographic, and scintigraphic studies and a test of ultrasound-induced pain. When initially seen, 15 had stress fractures confirmed by scintigraphy. Of these, 12 had abnormal thermograms, eight had positive test results for ultrasound-induced pain, and seven had abnormal radiographs. Thermography used alone seemed to be a safe, rapid means of diagnosis for stress fractures in the tibia or fibula and was not found to be related to symptom duration. In the radiologically normal group of stress fractures, four (50%) had positive test results for ultrasound stress tests and normal thermograms. The combination of these two tests should provide an early method of detecting stress fractures in the tibia and fibula, thereby avoiding scintiscans in some athletes.

Patello-femoral arthralgia in athletes attending a Sports Injury Clinic.

Over a five year period, 137 athletes presented to a Sports Injury Clinic with patello-femoral arthralgia. This was 5.4% of the total injuries seen and a quarter of all knee problems treated. Running contributed to 32% of the athletes with patello-femoral pain. There was a 4:1 male:female ratio and nearly 70% were in the 16-25 year age range. A follow-up questionnaire was sent to 72 athletes seen in the last two years with a 78% response rate. Symptoms and treatment are discussed. After conservative therapy only 28.6% were entirely symptom free with a mean follow up of 13.1 months.

Athletes attending a sports injury clinic--a review.

In a prospective study over the two years 1981-1982, there were 1186 separate sporting injuries treated at a Sports Injury Clinic. Just over 75% of patients were aged between 16 and 25 years old, while 80% were male. Football, Rugby, Running, Squash and Rowing contributed over 70% of these injuries. The commonest injuries were to the lower limb and lumbar region. In 43% of knee injuries there was strain of the collateral ligaments, while another 26% had patello-femoral pain. Short distance running was associated with an increase in shin splints, tibial stress fractures and hamstring injuries. Long distance running was associated with an increase in ankle and foot injuries. Sports Injury Clinics can benefit the injured athlete and there appears to be a need for their development in major hospitals.

Scleritis and associated disease.

One hundred patients (66 women and 34 men) who presented consecutively to Moorfields Eye Hospital with scleral disease underwent medical examination. Thirteen were found to have seropositive rheumatoid arthritis and another 16 also had rheumatoid factor present (Rheumaton test). Autoantibodies were present in 35% of patients, being most common in the elderly and most frequent in cases of necrotising and diffuse scleritis. Although scleral disease is uncommon, it is associated with connective-tissue disorders. Scleritis may be severe and destructive locally, and one series showed that 27% of patients who develop necrotising scleritis are dead from systemic complications within five years. It is therefore important for it to be correctly diagnosed and effectively treated at an early stage.

Parallel studies of HLA antigens in patients with rheumatic heart disease and scleritis: comparisons with three control populations.

Parallel studies were carried out on HLA antigens in patients with rheumatic heart disease and scleritis. Comparison with one control population showed a significant excess of BW15 in both disease samples, while a comparison with two other control populations, showed the excess not to be significant. Possible reasons for this discrepancy are discussed, together with the effect on statistical significance of a small percentage of false antigen assignments in one of the samples. A small systematic serological false assignment of an antigen can, by itself, produce a significant result more easily if the frequency of the antigen being detected is low than if it is high. It is suggested that this effect may contribute to the discrepant significant results obtained by different workers in some HLA and disease studies.