[The research advances and applications of genome editing in hereditary eye diseases].

Genome editing is a cutting-edge technology that generates DNA double strand breaks at the specific genomic DNA sequence through nuclease recognition and cleavage, and then achieves insertion, replacement, or deletion of the target gene via endogenous DNA repair mechanisms, such as non-homologous end joining, homology directed repair, and homologous recombination. So far, more than 600 human hereditary eye diseases and systemic hereditary diseases with ocular phenotypes have been found. However, most of these diseases are of incompletely elucidated pathogenesis and without effective therapies. Genome editing technology can precisely target and alter the genomes of animals, establish animal models of the hereditary diseases, and elucidate the relationship between the target gene and the disease phenotype, thereby providing a powerful approach to studying the pathogenic mechanisms underlying the hereditary eye diseases. In addition, correction of gene mutations by the genome editing brings a new hope to gene therapy for the hereditary eye diseases. This review introduces the molecular characteristics of 4 major enzymes used in the genome editing, including homing endonucleases, zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/ CRISPR-associated protein 9 (Cas9), and summarizes the current applications of this technology in investigating the pathogenic mechanisms underlying the hereditary eye diseases. (Chin J Ophthalmol, 2017, 53: 386-371).

[Analysis of bacterial pathogens and clinical characteristics of children with respiratory tract infections in Tianjin].

Objective: To analyze the pathogenic bacteria and epidemiological characteristics in children with respiratory tract infection in Tianjin area. Methods: Retrospective case analysis was performed on 2 392 hospitalized children in the wards of respiratory diseases, intensive care unit and special care ward of Tianjin Children's Hospital from June 2018 to May 2019. Thirteen pathogenic bacteria in deep sputum and bronchoalveolar lavage fluid samples were detected by loop-mediated isothermal amplification. The laboratory data and clinical characteristics of the infected children were analyzed, and the comparison between groups was performed by t test or χ2 test. Results: Among 2 392 cases, 1 407 were males and 985 females. There was no significant difference in the detection rate between males and females (72.5% (1 020/1 407) vs.74.2% (731/985), χ2=0.87, P=0.35). A total of 1 751 strains and 12 kinds of positive respiratory pathogens were detected, with a detection rate of 73.2%. Among them, 913 (38.2%) strains were Mycoplasma pneumoniae (MP), 514 (21.5%) were Streptococcus pneumoniae (Sp), 381 (15.9%) were Methicillin-resistant Staphylococcus aureus (MRSA) and 279 (11.7%) were Hemophilus influenzae (Hi). There was significant difference in the detection rate of pathogens among different age groups (χ²=83.67, P<0.01). The positive rate of alveolar lavage fluid group was higher than that of deep sputum fluid group [81.6% (614/752) vs. 69.3% (1 137/1 640), χ2=39.89, P<0.01]. The length of hospital stay of children infected with different pathogens was significantly different (all P<0.01). There was significant difference in duration of fever among children infected with different pathogens (χ²=228.69,103.56, 3.96, 27.38,24.50,41.66, all P<0.05). There were 63 (7.7%) cases of atelectasis, 260 (31.9%) cases of pleurisy and 120 (14.7%) cases of pleural effusion in MP children. Children with Sma were most likely to involve the heart system (2/9), and children with Eco infection had a higher incidence of complications such as those of blood (3/19), urinary (2/19), digestive systems(4/19), systemic inflammatory response syndrome and sepsis (1/19). Conclusions: The main bacterial pathogens of respiratory tract infection in children in Tianjin were MP, Sp, MRSA and Hi. It is suggested that clinicians should not only pay attention to the respiratory symptoms of children, but also pay attention to the complications caused by bacterial pathogen infection, so as to prevent the deterioration of the disease and improve the prognosis.

Reconstruction of the thumb by a free pedal neurovascular flap and composite phalanx-joint-tendon homograft: a preliminary report.

A one-stage procedure for reconstructing the thumb was used in 10 patients, using previously frozen bone-joint-tendon composite allograft and a neurovascular free skin flap from the foot. Levels of injury ranged from the greater multiangular bone to the middle of the first phalanx. Postoperative bony absorption and joint degeneration were minimized, and no cases of tissue rejection were encountered. Further advantages of the procedure are that subsequent nerve regeneration and cutaneous sensibility are improved, and that there are better functional and aesthetic results, compared to other techniques. Using this procedure, donor site dysfunction is also minimal.

[Clinical evaluation of frozen-phalanx-joint-tendon-sheath composite tissue allograft].

OBJECTIVE: To evaluate clinical result of reconstructed thumb and finger with a free hallux nail flap(HNF) and frozen-phalanx-joint-tendon-sheath composite tissue allograft in 270 cases. METHODS: The patients were followed up with reexamination in the ambulant clinic, communication, X-ray photography, lab-examination, isotope 99mTc MDP and reoperation. The data were analyzed by statistics or proved by clinical observation, which were followed up for five years in average (ranging from five months to sixteen years). RESULTS: Enveloping the allogeneic finger composite tissue with self-HNF and pieces of phalanx of great toe, it could reconstruct a thumb or finger with good contour and nutrition. The excellent rate of opposition function of the reconstructed thumbs was 71.91%. The sense of the fingers recovered after 3 months to 8 months of operation. Two-point discrimination was 3 mm to 15 mm. The junction between implanted allo-phalanges and auto-phalanges could be hastened by implanted with vascularized autogenous phalanx pieces in the HNF. The isotope 99mTc MDP was used to take X-ray photography in 24 cases for four months to 9 years and seven months, which showed that the blood vessels grew into the allo-phalanges. However, the Charcot's arthropathy of allogeneic joints and bony absorption still could be seen in some cases. That might be concerned with chronic abrasion of joint or chronic rejection of host to graft. CONCLUSION: The operation is fit for repairing the defect of thumb or finger in any degree. The implanted vascularized self-phalanx pieces can promote bone union, but it can not prevent the allogeneic joints from arthropathy or bone absorption.