Hemiarthroplasty and total hip arthroplasty are routinely performed procedures. A comparison of these procedures in tumor patients can be performed based on complications and functional outcomes. To weigh the advantages and disadvantages of both procedures, a comparative study is indeed required to decide which procedure is more beneficial for primary bone tumor patients. The outcomes of proximal femur tumor-resected patients were collected from research reports from PubMed, MEDLINE, EMBASE, Cochrane, and Google Scholar until 30 December 2022. Differences between these two operative procedures in primary bone tumors patients were analyzed based on dislocation, infection, local recurrence, MSTS, and HHS. Six articles were included according to the selection criteria with a total of 360 patients. Our results showed that there was a significant difference in our primary outcome as hemiarthroplasty participants encountered less dislocation than those with total hip arthroplasty. Moreover, the secondary outcomes of our study were similar. Proximal femur bone tumors, when resected, tend to produce more complications and decrease functional ability due to extensive tumor extension and soft tissue involvement. The lower dislocation rate in hemiarthroplasty participants emphasizes the importance of preserving the acetabular head in hemiarthroplasty as a key to preventing dislocation.

Fowl adenovirus (FAdV) was first reported in Angara Goth, Pakistan, in 1987. For this reason, it is also known as \"Angara disease.\" It was later reported in China, Japan, South Korea, India, the United States, Canada, and other countries and regions, causing huge economic losses in the poultry industry worldwide. Notably, since June 2015, a natural outbreak of severe hydropericardium hepatitis syndrome (HHS), associated with a hypervirulent novel genotype FAdV-4 infection, has emerged in most provinces of China. The novel virus FAdV-4 spread rapidly and induced a 30-100% mortality rate, causing huge economic losses and threatening the green and healthy poultry breeding industry. Vaccines against FAdV-4, especially the emerging novel genotype, play a critical role and will be the most efficient tool for preventing and controlling HHS. Various types of FAdV-4 vaccines have been developed and evaluated, such as inactivated, live-attenuated, subunit, and combined vaccines. They have made great contributions to the control of HHS, but the details of cross-protection within FAdVs and the immunogenicity of different vaccines require further investigation. This review highlights the recent advances in developing the FAdV-4 vaccine and promising new vaccines for future research.

Severe hepatitis-hydropericardium syndrome (HHS) associated with a novel viral genotype, fowl adenovirus 4 (FAdV-4), has emerged and widely spread in China since 2015, causing severe economic losses to the poultry industry. We previously reported that the hexon gene is responsible for pathogenicity and obtained a non-pathogenic hexon-replacement rHN20 strain; however, the lack of information about the non-essential regions for virus replication limits the development of a FAdV-4 vector. This study first established an enhanced green fluorescent protein (EGFP)-indicator virus based on the FAdV-4 reverse genetic technique, effective for batch operations in the virus genome. Based on this, 10 open reading frames (ORFs) at the left end and 13 ORFs at the right end of the novel FAdV-4 genome were deleted separately and identified as non-essential genes for viral replication, providing preliminary insertion sites for foreign genes. To further improve its feasibility as a vaccine vector, seven combinations of ORFs were successfully replaced with EGFP without affecting the immunogenicity of the vector backbone. Finally, a recombinant rHN20-vvIBDV-VP2 strain, expressing the VP2 protein of very virulent infectious bursa disease virus (vvIBDV), was rescued and showed complete protection against FAdV-4 and vvIBDV. Thus, the novel FAdV-4 vector could provide sufficient protection for HHS and efficient exogenous gene delivery. Overall, our findings systemically identified 23 non-essential ORFs for FAdV-4 replication and seven foreign gene insertion regions, providing valuable information for an in-depth understanding of the novel FAdV-4 pathogenesis and development of multivalent vaccines.

Hepatitis-hydropericardium syndrome (HHS) is widespread in China and causes high chicken mortality that results in great economic losses. A safe and effective vaccine is needed, and a subunit vaccine has potential for development. In this study, a truncated region of the FAdV-4 fiber 2 fused with coding sequence of one epitope of hexon was expressed in a prokaryotic expression system, and the immune protective effects of different doses of recombinant fiber 2 subunit vaccine on SPF chickens were compared. The recombinant fiber2 (Gly275- Pro479 aa)-hexon (Met21-Val51 aa) protein (rFH) obtained in Escherichia coli showed good solubility. The chicken survival rate at the lowest dose (2.5 μg/bird) was 75% (6/8), and at higher doses (≥5 μg/bird) was 100% (8/8) in challenge experiment. Two chickens in the 2.5 μg/bird treatment showed severe lesions, while birds in the higher dose treatments showed no obvious tissue damage as determined by histopathologic analysis of liver and spleen. Absolute quantitative real-time PCR showed no viral load in the ≥5 μg/bird treatments, but two chickens in the 2.5 μg/bird treatment had high viral loads. The challenge experience demonstrated that the rFH vaccine provided 100% protection at ≥5 μg/bird. These results suggested that rFH protein as an effective vaccine to protect against FAdV-4 and provided a new idea for the development of vaccine against HHS.

Hypervirulent fowl adenovirus serotype 4 (hvFAdV-4) has emerged as a major pathogen of hepatitis-hydropericardium syndrome (HHS) with increased mortality in chickens, resulting in economic losses to the Chinese poultry industry since June 2015. Here, we isolated a hypervirulent FAdV-4 (hvFAdV-4) strain (designated GD616) from 25-day-old meat-type chickens with severe HHS in Guangdong Province China in June 2017. The whole genome of the strain GD616 shares high homology with those in the recently-reported hvFAdV-4 isolates in China, with natural deletions of ORF19 and ORF27. A comparative analysis of Hexon and Fiber-2 proteins revealed that 2 unique amino acid residues at positions 378 and 453 of the Fiber-2 protein might be associated with virulence due to their occurrences in all the hvFAdV-4 isolates only. To systemically evaluate the effect of age on the susceptibility of chickens to hvFAdV-4, we used this hvFAdV-4 strain to intramuscularly inoculate 7- to 180-day-old specific-pathogen-free chickens for the evaluation of pathogenicity. These results showed that the pathogenicity of the hvFAdV-4 strain GD616 to chickens exhibited age-relatedness, with younger than 59-day-old chickens showing 100% morbidity and mortality, while 180-day-old chickens still exhibited a hydropericardium syndrome-like clinicopathology with 60% morbidity and 20% mortality. These findings enrich the current available knowledge regarding the pathogenicity of the hypervirulent FAdV-4 virus in chickens with a wide range of ages, which assists with the selection of suitable-aged chickens for the evaluation of hvFAdV-4 vaccines.

Clinical cases of hepatitis-hydropericardium syndrome (HHS) from fowl adenovirus serotype 4 (FAdV-4) have increased in China since 2013. Therefore, the development of a new serologic method for HHS detection is now urgent. Here, the FAdV-4 strain JSJ13 was used to construct a plasmid for prokaryotic expression of the JSJ13 fiber-2 protein. The protein, purified by affinity chromatography, was refolded by gradient dialysis. After coating a 96-well plate with the purified fiber-2 protein (1.5 μg/ml), standard serum and secondary antibodies (1:200 and 1:6000 dilutions, respectively) were used to develop an indirect ELISA (I-ELISA). Nine field-collected serum samples and JSJ13-positive serum were tested by I-ELISA and the results corresponded with those of the serum neutralization test. The I-ELISA was used to test 450 clinical serum samples from different parts of China. Chickens from nonvaccinated flocks had low antibody titers and low virus positivity rates. In contrast, FAdV-4 vaccinated chickens were strongly positive, and the positivity rates of all the flocks exceeded 73.3%. The newly developed I-ELISA with the recombinant JSJ13 fiber-2 protein as the antigen detected antibodies to FAdV-4 accurately and sensitively.

As the number of hepatitis hydropericardium syndrome (HHS) cases has increased in recent years in China, development of a safe and effective vaccine is now urgent. To address this problem a subunit vaccine is a good option, we here systematically investigated the minimum immune dose of a subunit vaccine against HHS based on recombinant fowl adenovirus serotype 4 (FAdV-4) fiber-2 protein and compared the effects between this subunit vaccine and an inactivated oil-emulsion FAdV-4 vaccine in a vaccination trial. The results revealed that the lowest dose of recombinant fiber-2 protein that could provide 100% protection against challenge with virulent FAdV-4 strain HB1501 as well as elicit protective immunity was 2.5 μg/bird. Neither clinical signs nor gross lesions were observed in chickens. In addition, immunization of specific-pathogen-free (SPF) chickens with recombinant fiber-2 protein (≥2.5 μg/bird) could induce quicker and stronger immune responses than the inactivated oil-emulsion FAdV-4 vaccine. These findings provide important information about the development of subunit vaccines for the control of HHS.