Biomechanical testing of a new plate system for the distal humerus compared to two well-established implants

Purpose

A biomechanical study was performed to test the hypothesis that a new anatomically preformed, thinner, soft-tissue protecting plate system for distal humeral fractures (Tifix®-hybridplate [HP]) would show comparable results in the quasi-static and dynamic testings compared to two conventional implants: The 3.5-mm reconstruction plate (RP) providing primary stability with normal bone mineral density (BMD), and a multidirectional locking plate (Tifix®-plate [P]) which can be used with poor bone quality.

Methods

The Tifix®-HP was developed by the working group. The biomechanical testing was performed on a C2-fracture-model in 24 synthetic humeri. Three groups, each with eight bone-implant-constructs, were analysed in quasi-static and dynamic tests.

Results

The quasi-static measurements showed that under extension loading both locking plates (Tifix®-P, Tifix®-HP) were significantly stiffer than the reconstruction plate, and that the Tifix®-HP had a significantly lower stiffness than the two other implants under flexion loading. In the dynamic tests the Tifix®-P allowed significantly less fracture motion compared to the Tifix®-HP and the reconstruction plate. In an osteopaenic bone model locking plates failed only under much higher dynamic force than the reconstruction plate. The reconstruction plate and the Tifix®-P always failed through screw loosening, whereas the newly developed Tifix®-HP showed screw loosening in only one third of cases.

Conclusion

The hypothesis that the newly designed plate system showed comparable results in the quasi-static and dynamic tests compared to the conventional implants with a significantly lower implant volume and thickness was confirmed.     

Immunogenicity of Quadrivalent Human Papillomavirus Vaccine in Organ Transplant Recipients

Solid organ transplant recipients are at risk of morbidity from human papillomavirus (HPV)‐related diseases. Quadrivalent HPV vaccine is recommended for posttransplant patients but there are no data on vaccine immunogenicity. We determined the immunogenicity of HPV vaccine in a cohort of young adult transplant patients. Patients were immunized with three doses of quadrivalent HPV vaccine containing viral types 6, 11, 16 and 18. Immunogenicity was determined by type‐specific viral‐like protein ELISA. Four weeks after the last dose of vaccine, a vaccine response was seen in 63.2%, 68.4%, 63.2% and 52.6% for HPV 6, 11, 16 and 18, respectively. Factors that led to reduced immunogenicity were vaccination early after transplant (p = 0.019), having a lung transplant (p = 0.007) and having higher tacrolimus levels (p = 0.048). At 12 months, there were significant declines in antibody titer for all HPV types although the number of patients who remained seropositive did not significantly differ. The vaccine was safe and well tolerated. We show suboptimal immunogenicity of HPV vaccine in transplant patients. This is important for counseling patients who choose to receive this vaccine. Further studies are needed to determine an optimal HPV vaccine type and schedule for this population.     

Sex-specific influence of angiotensin type 2 receptor stimulation on renal function: a novel therapeutic target for hypertension

The renin-angiotensin system is a powerful regulator of arterial pressure and body fluid volume. Increasing evidence suggests that the angiotensin type 2 receptor (AT(2)R), which mediates the vasodilatory and natriuretic actions of angiotensin peptides, is enhanced in females and may, therefore, represent an innovative therapeutic target. We investigated the therapeutic potential of direct AT(2)R stimulation on renal function in 11- to 12-week-old anesthetized male and female Sprague-Dawley rats. Renal blood flow was examined in response to a graded infusion of the highly selective, nonpeptide AT(2)R agonist, compound 21 (100, 200, and 300 ng/kg per minute), in the presence and absence of AT(2)R blockade (PD123319; 1 mg/kg per hour). Direct AT(2)R stimulation significantly increased renal blood flow in both males and females, without influencing arterial pressure. This was dose dependent in females only and occurred to a greater extent in females at the highest dose of compound 21 administered (males: 13.1±2.4% versus females: 23.0±3.2% change in renal blood flow at 300 ng/kg per minute versus baseline; P<0.01). In addition, AT(2)R stimulation significantly increased sodium and water excretion to a similar extent in males and females (P(Group)=0.05 and 0.005). However, there was no significant change in glomerular filtration rate in either sex, suggesting that altered tubular function may be responsible for AT(2)R-induced natriuresis rather than hemodynamic effects. Taken together, this study provides evidence that direct AT(2)R stimulation produces vasodilatory and natriuretic effects in the male and female kidney. The AT(2)R may, therefore, represent a valuable therapeutic target for the treatment of renal and cardiovascular diseases in both men and women.     

An outbreak of Arthroderma vanbreuseghemii dermatophytosis at a veterinary school associated with an infected horse

We report a case of an outbreak of inflammatory dermatophytoses caused by Arthroderma vanbreuseghemii (formally Trichophyton mentagrophytes pro parte) that involved an infected horse, the owner and at least 20 students, staff and stablemen at a veterinary school in Bern (Switzerland) that presented highly inflammatory dermatitis of the body and the face. Transmission from human to human was also recorded as one patient was the partner of an infected person. Both the phenotypic characteristics and ITS sequence of the dermatophytes isolated from the horse and patients were identical, consistent with the conclusion that the fungus originated from the horse. Three infected persons had not been in direct contact with the horse. Although direct transmission from human to human cannot be ruled out, fomites were most likely the source of infection for these three patients. Inspection of the literature at the end of the nineteenth and beginning of the twentieth century revealed that this dermatophyte was frequently transmitted from horses to humans in contact with horses (stablemen, coachmen, carters and artillery soldiers). The rarity of the present case report at the present time is likely related to the transformation of civilisation from the nineteenth century to nowadays in Europe with the change of horse husbandry. In addition, the inadequate immune response of the horse and the high number of people in contact with it at the equine clinic may explain the exceptional aspect of this case report.     

Biological effects of a new ultraviolet A1 prototype based on light-emitting diodes on the treatment of localized scleroderma

Ultraviolet A₁ (UVA₁) phototherapy (spectral range 340-400 nm) is a well-established treatment option for various skin diseases such as localized scleroderma. Recent improvements of conventional UVA₁ light sources (metal-halide or fluorescent lamps) have brought attention to a new light-emitting diode (LED) technology with remarkable advantages in handling and clinical routine. This study provides a preclinical histological and molecular evaluation of an LED-based UVA₁ prototype with a narrower spectral range (360-400 nm) for treating localized scleroderma. Scleroderma mouse models and fibroblasts in vitro were exposed to LED-based UVA₁ phototherapy or to irradiation with a commercially available metal-halide lamp emitting low-dose (20, 40 J/cm²), medium-dose (60 J/cm²) and high-dose (80, 100 J/cm²) UVA₁ light. Both UVA₁ light sources affected inflammatory genes (IL-1α and IL-6) and growth factors (TGFß-1 and TGFß-2). Increased collagen type 1 was reduced after UVA₁ phototherapy. Matrix metalloproteinase-1 was more enhanced after a medium dose of LED-based UVA₁ phototherapy than after conventional treatment. In vivo, dermal thickness and the amount of collagen were reduced after both treatment methods. Remarkably, myofibroblasts were more effectively reduced by a medium dose of LED-based UVA₁ phototherapy. The study indicates that LED-based UVA₁ phototherapy yields similar or even better results than conventional treatment. In terms of biosafety and patient comfort, LED-based UVA₁ phototherapy offers clear advantages over conventional treatment because of the use of a narrower and less harmful UVA₁ spectrum, less heat generation and shorter treatment times at the same irradiation intensity. Clinical studies are required to confirm these results in patients with localized scleroderma.     

Einzelreferate und Buchbesprechungen

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Über den Wärmestillstand des Froschherzens

Ohne ZusammenfassungHerrn Geheimrat v. Kries sage ich für die Anregung und Beratung bei meiner Arbeit auch an dieser Stelle meinen ergebensten Dank.     

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