Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients.

Vaccination of egg-allergic individuals has been a historical concern, particularly for influenza and measles-mumps-rubella-varicella vaccines that are developed in chicken egg embryos or chicken cell fibroblasts. The egg proteins in these vaccines were believed to trigger an immediate allergic reaction in egg-allergic individuals. However, recently published international guidelines have updated their recommendations and now state that these vaccines can be safely administered to egg-allergic individuals. This joint consensus statement by the Hong Kong Institute of Allergy and the Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases summarises the updates and provides recommendations for local general practitioners and paediatricians. Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients Background.

The Use of Europiumstearate to Trace Polyethylene Wear Debris in Joint Fluid after Prosthetic Joint Replacement - A Feasibility Study.

Ultra-high molecular weight polyethylene (UHMWPE) is the most common counterface material against metals or ceramics in artificial hip or knee joints. Wear and the resulting particulate debris, however, limit the life span of the implant. In this study, the general feasibility of using Europium (Eu) as tracer material to quantify UHMWPE wear in joint fluid is investigated. Using Inductively Coupled Mass Spectrometry (ICP-MS), recovery experiments of Eu in artificial joint fluid were performed. In order to dope polyethylene with 50 ppm Eu, nascent UHMWPE powder was mixed with a solution of Eu-stearate. The heterogeneity of the mixture was assessed by determining the coefficient of variation (CV) of the Eu content in various weighted samples. After molding of the UHMWPE powder mixture, cylindrical pins of 10 mm diameter were machined and worn against cobalt-chromium metal disks submersed in artificial joint fluid. The Eu-content of fluid samples taken at certain time intervals was measured and compared with UHMWPE weight loss of the pins. A satisfactory homogenization of Eu in the UHMWPE powder was achieved. Tracer-based and weight-loss determined wear rates were highly correlated (Pearson correlation coefficients > 0.991). Also the detection bias was within acceptable limits. Thus both methods demonstrated good agreement.

In-vivo kinematics of knee prostheses patients during level walking compared with the ISO force-controlled simulator standard.

Differences between wear-scar features of simulator-tested and retrieved tibial total knee replacement (TKR) liners have been reported. This disagreement may result from differences between in-vivo kinematic profiles and those defined by the standard. The purpose of this study was to determine the knee kinematics of a TKR subject group during level walking and to compare them with the motion profiles produced by a wear test conducted according to the force-controlled knee wear testing ISO 14243-1 standard. Ten patients with a posterior cruciate ligament-retaining TKR design were gait tested using the point cluster technique to obtain flexion-extension (FE) rotation, anterior-posterior (AP) translation, and internal-external (IE) rotation motions during a complete cycle of level walking. Motion data were directly compared with the output kinematics from the wear test. The subjects exhibited an FE rotation pattern similar to the output from ISO-14243-1; however, they had higher midstance knee flexion angles. For both AP translation and IE rotation, the standard profiles had significantly smaller total ranges of motion than seen in vivo, with noticeably different patterns of motions. For this particular implant design, significant differences were found in both the pattern and the magnitudes of in-vivo motion during level walking compared with the ISO-14243-1 standard.

Anomalous thermal denaturing of proteins adsorbed to nanoparticles.

We have used localized surface plasmon resonance (LSPR) to monitor the structural changes that accompany thermal denaturing of bovine serum albumin (BSA) adsorbed onto gold nanospheres of size 5nm-60nm. The effect of the protein on the LSPR was monitored by visible extinction spectroscopy. The position of the resonance is affected by the conformation of the adsorbed protein layer, and as such can be used as a very sensitive probe of thermal denaturing that is specific to the adsorbed protein. The results are compared to detailed calculations and show that full calculations can lead to significant increases in knowledge where gold nanospheres are used as biosensors. Thermal denaturing on spheres with diameter > 20 nm show strong similarity to bulk calorimetric studies of BSA in solution. BSA adsorbed on nanospheres with d [Symbol: see text] 15nm shows a qualitative difference in behavior, suggesting a sensitivity of denaturing characteristics on local surface curvature. This may have important implications for other protein-nanoparticle interactions.

New CCR5 variants associated with reduced HIV coreceptor function in southeast Asia.

BACKGROUND: Despite multiple exposure to HIV-1, some individuals remain uninfected. This resistance has been associated with homozygosity for a 32 base pair deletion in the gene for the CCR5 receptor. This variant occurs frequently in Caucasians but is extremely rare in Asians or Africans. OBJECTIVE: To identify variations in CCR5 receptor gene that affect susceptibility to HIV infection in non-Caucasians. METHODS: CCR5 coding region polymorphisms were screened in three groups of Vietnamese subjects: 47 HIV-1 infected intravascular drug users, 50 highly HIV-1-exposed but seronegative intravascular drug users and 37 HIV-1-unexposed seronegative individuals. DNA was analysed by denaturing high performance liquid chromatography; this was followed by examination of the biochemical and HIV coreceptor properties of the coding regions. RESULTS: Five CCR5 coding region variants were identified in this Vietnamese population. The S185R, I254T and C269F mutations have not been previously described; G106R and R223Q have already been found in other Asian populations, but the functional properties of G106R is not known. These variants differed in biochemical and HIV coreceptor properties. S185R and I254T variants had receptor and coreceptor activities comparable to that of the wild type, whereas C269F and G106R behaved differently. This latter pair are poorly expressed at the cell surface, weakly bind macrophage inflammatory protein 1beta (CCL4) and RANTES (CCL5), and display reduced HIV-1 coreceptor efficiency. CONCLUSIONS: Among the five CCR5 variants found in this Vietnamese population, G106R and C269F displayed significant modifications of their receptor and coreceptor properties, which may contribute to susceptibility to HIV-1 infection and/or disease progression within this population.

Cutting edge: increased NK cell activity in HIV-1-exposed but uninfected Vietnamese intravascular drug users.

We addressed the role of innate immunity in the protection against HIV-1 infection by studying NK cell function in 37 Vietnamese intravascular drug users (IDUs), who appeared to remain HIV-1 uninfected despite many years of high-risk exposure (exposed uninfected, EU), 10 IDUs who underwent seroconversion and 28 unexposed blood donors. Main results were: NK cell lytic activities against both the NK-susceptible K562 cell line and the NK-resistant Daudi cell line were significantly augmented in EU IDUs compared with either controls or seroconverters before or after seroconversion; NK cells producing the cytokines IFN-gamma and TNF-alpha and the beta chemokines CCL3, CCL4, and CCL5 were also increased in the EU IDUs, either after in vitro activation or without stimulation. The finding of an enhanced NK cell function in EU IDUs, especially compared with IDUs who became HIV-1 infected, supports the hypothesis that NK cells contribute to the protection against HIV-1 infection.

CD4 cell and CD8 cell-mediated resistance to HIV-1 infection in exposed uninfected intravascular drug users in Vietnam.

OBJECTIVE: To identify mechanisms of resistance to HIV-1 infection in exposed uninfected individuals. DESIGN: We examined in-vitro cell susceptibility to HIV-1 infection in highly exposed Vietnamese intravascular drug users (IDU) who, despite a history of more than 10 years of drug use and a high prevalence of other blood-borne viral infections, remain apparently HIV uninfected. METHODS: Forty-five exposed uninfected IDU and 50 blood donors were included in the study. Peripheral blood mononuclear cells (PBMC) or CD4 cell susceptibilities to HIV infection were evaluated using three HIV-1 isolates with different tropisms. Polymerase chain reaction analysis of HIV-1-DNA replication intermediates was used to characterize the restriction of HIV-1 replication in CD4 cells. Homologous CD8 cells were mixed with infected CD4 cells to evaluate their role in virus suppression. RESULTS: We observed a relative resistance to PBMC infection with HIV-1 in 21 out of 45 exposed uninfected IDU, but only in five out of 50 unexposed controls (P < 0.001). PBMC resistance was related either to an inhibition of HIV-1 replication in CD4 cells or to CD8 cell-mediated viral suppression. HIV-1 replication in CD4 cells was restricted at the early stages of the viral cycle. CONCLUSION: Reduced PBMC susceptibility to HIV-1 infection was associated with resistance to infection in exposed uninfected IDU. Distinct mechanisms are involved in in-vitro resistance and may contribute to the apparent protection from HIV-1 transmission in this systemically exposed population.