Patellofemoral joint arthroplasty: patient selection,surgical technique and outcomes

Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.     

Checkpoint-blocker-induced autoimmunity is associated with favourable outcome in metastatic melanoma and distinct T-cell expression profiles

Background Immune checkpoint blockers (ICBs) activate CD8⁺ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8⁺ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10⁻⁶). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8⁺ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma     

Spatial restriction of light adaptation and mutation-induced inactivation in fly photoreceptors

The spatial spread within fly photoreceptors of 2 forms of desensitization by bright light have been investigated: the natural process of light adaptation in normal Musca photoreceptors and a receptor-potential inactivation in the no-steady-state (nss) mutant of the sheep blowfly Lucilia. The suction-electrode method used for recording from vertebrate rods was applied to fly ommatidia. A single ommatidium in vitro was partially sucked into a recording pipette. Illumination of the portion of the ommatidium within the pipette resulted in a flow of current having a wave form similar to that of the receptor potential and polarity consistent with current flow into the illuminated region of the photoreceptors. Two 5-microns slits of light, positioned at right angles to the ommatidial axis, were employed to determine the spread of light adaptation or inactivation along the ommatidium. The intensity of a flash of light delivered to one (adapting) slit was adjusted until it produced a criterion fractional reduction in the response to the other (test) slit. The reciprocal of this intensity of the adapting slit was taken as a measure of the effectiveness of the slit in causing light adaptation or inactivation. The effectiveness of the slit in causing light adaptation in normal Musca ommatidia fell as the adapting and test slits were moved farther apart along the ommatidial axis, declining to half its maximal value at a distance of 13 +/- 2 microns. Similar measurements of the effectiveness of a slit in causing light-induced inactivation in the nss mutant of Lucilia also demonstrated localization, declining to half its maximal value at a distance between the slits of 9 +/- 1 microns. Neither light adaptation nor inactivation by the nss mutation, therefore, appear to be mediated by voltage or by a highly diffusible agent. The results are consistent with the idea that inactivation by the nss mutation replaces adaptation in the mutant photoreceptors.     

Flow measurement by the development of phase differences during slice formation in MR imaging

A method for measuring flow based on the shifting of the rephasing pulse following slice selection in partial saturation is described. The technique is based on a partial saturation sequence and retains much of the high signal which is a feature of the use of this sequence. Images obtained while encoding for the flow signal compated with those when not encoding appear very similar.     

Isolation of Stomatococcus mucilaginosus from drug user with endocarditis.

Stomatococcus mucilaginosus was isolated from the blood of a patient with endocarditis and a past history of drug abuse and aortic valve replacement. At autopsy, Gram stain of the aortic valve revealed gram-positive cocci. Our isolate was atypical for S. mucilaginosus in that colonies were nonmucoid and nonadherent to agar surfaces. Cellular capsules were demonstrated by light and electron microscopy. Phenotypic characteristics identified by conventional methods as well as profile numbers obtained by using two commercial identification systems for staphylococci, the API Staph-Ident and the dms Staph Trac, are presented. Practical tests that differentiate S. mucilaginosus from the genera Micrococcus and Staphylococcus include growth on nutrient agar containing salt and lysostaphin susceptibility. Additional tests that helped differentiate our isolate from group D streptococci included hydrolysis of L-pyrrolidonyl-beta-naphthylamide and streptococcal serogrouping.     

Straßenverkehrsrecht und Rettungsdienst

Legal uncertainties for emergency vehicle drivers can be avoided when fundamental rules are established. In particular, differentiation of special rights and rights of way is essential. Inherent in both is the urgency necessary to save human lives. The right of way signaled by flashing blue lights and siren does not however justify traffic violations but signifies rather a request to other traffic participants. In contrast, special rights require no announcement and constitute a justifiable reason for traffic violations. Even so they do not allow that other traffic participants be endangered or harmed. Adherence to these basic principles can prevent legal misinterpretations as well as rigid adoption of inflexible standards of behavior.     

Das neue österreichische Patientenverfügungsrecht

Austria’s new Living Wills Act (Patientenverfügungsgesetz, or PatVG) that came into effect on 1st of June 2006, is the first law in Austria to regulate the controversial issue of living wills. The PatVG provides for a right to refuse future medical treatment by making an advance directive in the form of a living will that is either binding or “to be taken into consideration”. However, the establishment of a binding living will is governed by strict criteria as regards form and content, and both a medical doctor and a legal expert must be involved. Compliance with a living will is not allowed where there is a legal obligation to give medical treatment. There is also a legal obligation to give medical treatment in emergency situations where the time involved in looking for a living will could seriously endanger the health or the life of a patient.