Ocular Ischemic Syndrome and Its Related Experimental Models.

Ocular ischemic syndrome (OIS) is one of the severe ocular disorders occurring from stenosis or occlusion of the carotid arteries. As the ophthalmic artery is derived from the branch of the carotid artery, stenosis or occlusion of the carotid arteries could induce chronic ocular hypoperfusion, finally leading to the development of OIS. To date, the pathophysiology of OIS is still not clearly unraveled. To better explore the pathophysiology of OIS, several experimental models have been developed in rats and mice. Surgical occlusion or stenosis of common carotid arteries or internal carotid arteries was conducted bilaterally or unilaterally for model development. In this regard, final ischemic outcomes in the eye varied depending on the surgical procedure, even though similar findings on ocular hypoperfusion could be observed. In the current review, we provide an overview of the pathophysiology of OIS from various experimental models, as well as several clinical cases. Moreover, we cover the status of current therapies for OIS along with promising preclinical treatments with recent advances. Our review will enable more comprehensive therapeutic approaches to prevent the development and/or progression of OIS.

Clinical and genetic analysis of the ABCA4 gene associated retinal dystrophy in a large Chinese cohort.

ABCA4 gene associated retinal dystrophies (ABCA4-RD) are a group of inherited eye diseases caused by ABCA4 gene mutations, including Stargardt disease, cone-rod dystrophy and retinitis pigmentosa. With the development of next-generation sequencing (NGS), numerous clinical and genetic studies on ABCA4-RD have been performed, and the genotype and phenotype spectra have been elucidated. However, most of the studies focused on the Caucasian population and limited studies of large Chinese ABCA4-RD cohorts were reported. In this study, we summarized the phenotypic and genotypic characteristics of 129 Chinese patients with ABCA4-RD. We found a mutation spectrum of Chinese patients which is considerably different from that of the Caucasian population and identified 35 novel ABCA4 mutations. We also reported some rare and special cases, such as, pedigrees with patients in two generations, patients diagnosed with cone-rod dystrophy or retinitis pigmentosa, patients with subretinal fibrosis and patients with preserved foveal structure. At the same time, we focused on the correlation between the genotypes and phenotypes. By the comprehensive analysis of multiple clinical examinations and the application of multiple regression analysis, we proved that patients with two "null" variants had a younger onset age and reached legal blindness earlier than patients with two "none-null" variants. Patients with one or more "none-null" variants tended to have better visual acuity and presented with milder fundus autofluorescence changes and more preserved rod functions on the full-field electroretinography than patients with two "null" variants. Furthermore, most patients with the p.(Phe2188Ser) variant shared a mild phenotype with a low fundus autofluorescence signal limited to the fovea and with normal full-field electroretinography responses. Our findings expand the variant spectrum of the ABCA4 gene and enhance the knowledge of Chinese patients with ABCA4-RD.

Clinical and genetic characteristics of Stargardt disease in a large Western China cohort: Report 1.

Stargardt disease 1 (STGD1) is the most prevalent retinal dystrophy caused by pathogenic biallelic ABCA4 variants. Forty-two unrelated patients mostly originating from Western China were recruited. Comprehensive ophthalmological examinations, including visual acuity measurements (subjective function), fundus autofluorescence (retinal imaging), and full-field electroretinography (objective function), were performed. Next-generation sequencing (target/whole exome) and direct sequencing were conducted. Genotype grouping was performed based on the presence of deleterious variants. The median age of onset/age was 10.0 (5-52)/29.5 (12-72) years, and the median visual acuity in the right/left eye was 1.30 (0.15-2.28)/1.30 (0.15-2.28) in the logarithm of the minimum angle of resolution unit. Ten patients (10/38, 27.0%) showed confined macular dysfunction, and 27 (27/37, 73.7%) had generalized retinal dysfunction. Fifty-eight pathogenic/likely pathogenic ABCA4 variants, including 14 novel variants, were identified. Eight patients (8/35, 22.8%) harbored multiple deleterious variants, and 17 (17/35, 48.6%) had a single deleterious variant. Significant associations were revealed between subjective functional, retinal imaging, and objective functional groups, identifying a significant genotype-phenotype association. This study illustrates a large phenotypic/genotypic spectrum in a large well-characterized STGD1 cohort. A distinct genetic background of the Chinese population from the Caucasian population was identified; meanwhile, a genotype-phenotype association was similarly represented.

RP2-associated retinal disorder in a Japanese cohort: Report of novel variants and a literature review, identifying a genotype-phenotype association.

The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X-linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2-associated retinal disorder (RP2-RD) from four Japanese families in a nationwide cohort. A systematic review of RP2-RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10-47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52-2.0)/1.10 (0.52-1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2-RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.

Clinical and genetic characteristics of 10 Japanese patients with PROM1-associated retinal disorder: A report of the phenotype spectrum and a literature review in the Japanese population.

Variants in the PROM1 gene are associated with cone (-rod) dystrophy, macular dystrophy, and other phenotypes. We describe the clinical and genetic characteristics of 10 patients from eight Japanese families with PROM1-associated retinal disorder (PROM1-RD) in a nationwide cohort. A literature review of PROM1-RD in the Japanese population was also performed. The median age at onset/examination of 10 patients was 31.0 (range, 10-45)/44.5 (22-73) years. All 10 patients showed atrophic macular changes. Seven patients (70.0%) had spared fovea to various degrees, approximately half of whom had maintained visual acuity. Generalized cone (-rod) dysfunction was demonstrated in all nine subjects with available electrophysiological data. Three PROM1 variants were identified in this study: one recurrent disease-causing variant (p.Arg373Cys), one novel putative disease-causing variant (p.Cys112Arg), and one novel variant of uncertain significance (VUS; p.Gly53Asp). Characteristic features of macular atrophy with generalized cone-dominated retinal dysfunction were shared among all 10 subjects with PROM1-RD, and the presence of foveal sparing was crucial in maintaining visual acuity. Together with the three previously reported variants [p.R373C, c.1551+1G>A (pathogenic), p.Asn580His (likely benign)] in the literature of Japanese patients, one prevalent missense variant (p.Arg373Cys, 6/9 families, 66.7%) detected in multiple studies was determined in the Japanese population, which was also frequently detected in the European population.

Mutations in the Spliceosome Component CWC27 Cause Retinal Degeneration with or without Additional Developmental Anomalies.

Pre-mRNA splicing factors play a fundamental role in regulating transcript diversity both temporally and spatially. Genetic defects in several spliceosome components have been linked to a set of non-overlapping spliceosomopathy phenotypes in humans, among which skeletal developmental defects and non-syndromic retinitis pigmentosa (RP) are frequent findings. Here we report that defects in spliceosome-associated protein CWC27 are associated with a spectrum of disease phenotypes ranging from isolated RP to severe syndromic forms. By whole-exome sequencing, recessive protein-truncating mutations in CWC27 were found in seven unrelated families that show a range of clinical phenotypes, including retinal degeneration, brachydactyly, craniofacial abnormalities, short stature, and neurological defects. Remarkably, variable expressivity of the human phenotype can be recapitulated in Cwc27 mutant mouse models, with significant embryonic lethality and severe phenotypes in the complete knockout mice while mice with a partial loss-of-function allele mimic the isolated retinal degeneration phenotype. Our study describes a retinal dystrophy-related phenotype spectrum as well as its genetic etiology and highlights the complexity of the spliceosomal gene network.

Clinical and Genetic Characteristics of East Asian Patients with Occult Macular Dystrophy (Miyake Disease): East Asia Occult Macular Dystrophy Studies Report Number 1.

PURPOSE: To describe the clinical and genetic characteristics of the cohort enrolled in the East Asian studies of occult macular dystrophy (OMD). DESIGN: International, multicenter, retrospective cohort studies. PARTICIPANTS: A total of 36 participants from 21 families with a clinical diagnosis of OMD and harboring pathogenic RP1L1 variants (i.e., Miyake disease) were enrolled from 3 centers in Japan, China, and South Korea. METHODS: A detailed history was obtained, and comprehensive ophthalmological examinations including spectral-domain OCT were performed. All detected sequence variants in the RP1L1 gene were reviewed, and in silico analysis was performed, including allele frequency analyses and pathogenicity predictions. MAIN OUTCOME MEASURES: Onset of disease, visual acuity (VA) converted to the logarithm of the minimum angle of resolution (logMAR), OCT findings, and effect of detected variants. RESULTS: Eleven families from Japan, 6 from South Korea, and 4 from China were recruited. There were 12 female and 24 male participants. The median age of onset was 25.5 years (range, 2-73), and the median age at the latest examination was 46.0 years (range, 11-86). The median VA (logMAR) was 0.65 (range, -0.08-1.22) in the right eye and 0.65 (-0.08-1.10) in the left eye. A significant correlation between onset of disease and VA was revealed. The Classical morphologic phenotype showing both blurred ellipsoid zone and absence of interdigitation zone of the photoreceptors was demonstrated in 30 patients (83.3%), and subtle photoreceptor architectural changes were demonstrated in 6 patients (16.6%). Eight pathogenic RP1L1 variants were identified, including 6 reported variants and 1 novel variant: p.R45W, p.T1194M/p.T1196I (complex), p.S1199C, p.G1200A, p.G1200D, p.V1201G, and p.S1198F, respectively. Two variants were recurrent: p.R45W (11 families, 52.4%) and p.S1199C (5 families, 23.8%). The pathogenic missense variants in 10 families (47.6%) were located within the previously reported unique motif, including 6 amino acids (1196-1201). CONCLUSIONS: There is a large spectrum of clinical findings in Miyake disease, including various onset of disease and VA, whereas the characteristic photoreceptor microstructures were shared in most cases. Two hot spots including amino acid numbers 45 and 1196-1201 in the RP1L1 gene were confirmed in the East Asian population.

Dual-entropy-driven catalytic amplification reaction for ultra-sensitive and visible detection of Hg2+ in water based on thymine-Hg2+-thymine coordination chemistry.

An ultra-sensitive and visible Hg2+ detection strategy was established. It was based on T-Hg2+-T coordination chemistry and a dual-entropy-driven catalytic reaction (EDCR). The dual EDCR was initiated by T-Hg2+-T coordination chemistry, resulting in the release of a G-rich sequence to form a hemin/G-quadruplex-HRP-mimicking DNAzyme, and then catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) into TMB+, with a color change from colorless to blue. This method showed great sensitivity and excellent selectivity, and the limit of detection reached 0.6 pM. The feasibility of this method was demonstrated by real water samples. Moreover, the visible color change provided the possibility of ultra-sensitive detection of Hg2+ by the naked eye.

PHENOTYPIC VARIABILITY OF RECESSIVE RDH12-ASSOCIATED RETINAL DYSTROPHY.

PURPOSE: To characterize the phenotypic variability and report the genetic defects in a cohort of Chinese patients with biallelic variants of the retinol dehydrogenase 12 (RDH12) gene. METHODS: The study included 38 patients from 38 unrelated families with biallelic pathogenic RDH12 variants. Systematic next-generation sequencing data analysis, Sanger sequencing validation, and segregation analysis were used to identify the pathogenic mutations. Detailed ophthalmic examinations, including electroretinogram, fundus photography, fundus autofluorescence and optical coherence tomography, and statistical analysis were performed to evaluate phenotype variability. RESULTS: Twenty-five different mutations of RDH12 were identified in the 38 families. Six of these variants were novel. Val146Asp was observed at the highest frequency (23.7%), and it was followed by Arg62Ter (14.5%) and Thr49Met (9.2%). Twenty-three probands were diagnosed with early-onset severe retinal dystrophy, 6 with Leber congenital amaurosis, 7 with autosomal recessive retinitis pigmentosa, and 2 with cone-rod dystrophy. Self-reported nyctalopia occurred in about a half of patients (55.3%) and was significantly more common among older patients (P < 0.01). Nyctalopia was not significantly associated with best-corrected visual acuity (P = 0.72), but older patients had significantly greater best-corrected visual acuity loss (P < 0.01). Only 15.8% of the patients had nystagmus, which was significantly more likely to occur among 36.8% of the patients with hyperopia >3D (P < 0.01) and/or in cases of reduced best-corrected visual acuity (P = 0.01), but was not associated with age (P = 0.87). CONCLUSION: Several high-frequency RDH12 variants were identified in patients with inherited retinal dystrophies, most of which were missense mutations. Variable but characteristic phenotypes of a progressive nature was observed. Overall, the findings indicated that biallelic RDH12 mutations are a common cause of early-onset retinal dystrophy and a rare cause of cone-rod dystrophy.

Entropy-driven catalytic reaction-induced hairpin structure switching for fluorometric detection of uranyl ions.

An ultra-sensitive and "turn-on" method is demonstrated for the determination of uranyl ion. The assay is based on hairpin-to-DNAzyme structure switching that is induced by an entropy-driven catalytic reaction. An UO22+-specific DNAzyme is cleaved by UO22+ to produce a DNA fragment. This fragment initiates the entropy-driven catalytic reaction to produce a large number of a sequence "R". The sequence R initiates the circular cleavage of FAM-labeled hairpins by switching the hairpin to Mg2+-specific DNAzyme structure. This causes the recovery of green fluorescence. The method works in the 20 pM to 800 pM concentration range and the limit of detection is 4 pM. Graphical abstract Entropy driven catalytic reaction induced hairpin structure switching for fluorometric detection of uranyl ions.

CEP78 is mutated in a distinct type of Usher syndrome.

BACKGROUND: Usher syndrome is a genetically heterogeneous disorder featured by combined visual impairment and hearing loss. Despite a dozen of genes involved in Usher syndrome having been identified, the genetic basis remains unknown in 20-30% of patients. In this study, we aimed to identify the novel disease-causing gene of a distinct subtype of Usher syndrome. METHODS: Ophthalmic examinations and hearing tests were performed on patients with Usher syndrome in two consanguineous families. Target capture sequencing was initially performed to screen causative mutations in known retinal disease-causing loci. Whole exome sequencing (WES) and whole genome sequencing (WGS) were applied for identifying novel disease-causing genes. RT-PCR and Sanger sequencing were performed to evaluate the splicing-altering effect of identified CEP78 variants. RESULTS: Patients from the two independent families show a mild Usher syndrome phenotype featured by juvenile or adult-onset cone-rod dystrophy and sensorineural hearing loss. WES and WGS identified two homozygous rare variants that affect mRNA splicing of a ciliary gene CEP78. RT-PCR confirmed that the two variants indeed lead to abnormal splicing, resulting in premature stop of protein translation due to frameshift. CONCLUSIONS: Our results provide evidence that CEP78 is a novel disease-causing gene for Usher syndrome, demonstrating an additional link between ciliopathy and Usher protein network in photoreceptor cells and inner ear hair cells.

Three-way DNA junction based platform for ultra-sensitive fluorometric detection of multiple metal ions as exemplified for Cu(II), Mg(II) and Pb(II).

A DNA-based fluorometric method is described for simultaneous determination of multiple metal ions. It is based on recycling cleavage of hairpins by using a three-way DNA junction structure. Three DNA sequences containing a binding region and an enzyme-strand (E-DNA) region are hybridized to form a three-way DNA junction. The enzyme strand regions at the end of the DNA sequence binds to the substrate sequence (S-DNA) at the loop of the hairpin to form typical DNAzyme structures. In the presence of analyte metal ions, the DNAzyme structure thus formed cleaves the loop of hairpins. This is accompanied by a release of fluorescently labeled DNA fragments and by quenching of fluorescence. The detection limits are 35 pM for Cu(II), 2 nM for Mg(II), and 8 pM for Pb(II). This method was successfully applied to the simultaneous determination of these ions in spiked human serum. Graphical abstract Schematic presentation of the recycling cleavage of hairpins by using a three-way DNA junction structure. It causes a release of fluorescently labeled DNA fragments and quenching of fluorescence. It was successfully applied to the simultaneous determination of Cu(II), Mg(II) and Pb(II) in spiked human serum.

A catalytic cleavage strategy for fluorometric determination of Hg(II) based on the use of a Mg(II)-dependent split DNAzyme and hairpins conjugated to gold nanoparticles.

A catalytic cleavage strategy was developed for the fluorometric determination of Hg(II). The method is based on the use of a Mg(II)-dependent split DNAzyme. Fluorophore labeled hairpins were conjugated to gold nanoparticles (AuNPs) upon which fluorescence is quenched. Thymine-Hg(II)-thymine (T-Hg(II)-T) interaction causes the two DNA sequences to form an entire enzyme-strand DNA (E-DNA). The E-DNA bind to the hairpins on the AuNPs to form a Mg(II)-dependent DNAzyme structure. The circular cleavage of hairpins results in a signal amplification and in the recovery of fluorescence. The assay has a limit of detection (LOD) as low as 80 pM of Hg(II). This LOD is comparable to those obtained with other amplification strategies. The method was successfully applied to the determination of Hg(II) in Chinese herbs (Atractylodes macrocephala Koidz). Graphical abstract Schematic of a catalytic cleavage strategy based on Mg(II)-dependent split DNAzyme for fluorometric determination of Hg(II).

The Trace Detection of Nitrite Ions Using Neutral Red Functionalized SH-ß-Cyclodextrin @Au Nanoparticles.

A novel fluorescence sensor of NR-ß-CD@AuNPs was prepared for the trace detection of nitrite in quantities as low as 4.25 × 10-3 µg∙mL-1 in an aqueous medium. The fluorescence was due to the host-guest inclusion complexes between neutral red (NR) molecules and gold nanoparticles (AuNPs), which were modified by per-6-mercapto-beta-cyclodextrins (SH-ß-CDs) as both a reducing agent and a stabilizer under microwave radiation. The color of the NR-ß-CD@AuNPs changed in the presence of nitrite ions. A sensor was applied to the determination of trace nitrites in environmental water samples with satisfactory results.

Mutations in crystallin genes result in congenital cataract associated with other ocular abnormalities.

Purpose: This study aims to describe the phenotypes and identify pathogenic mutations in Chinese patients who have congenital cataracts associated with other ocular abnormalities. Methods: Eleven patients from four unrelated Chinese families plus two simplex cases were enrolled in this study. Detailed ophthalmic examinations were performed. DNA samples were isolated from peripheral blood collected from the patients. Next-generation sequencing of known ocular genes was applied to the proband of each family and two simplex cases to find pathogenic variances. PCR and Sanger sequencing were conducted for validation and segregation tests. Results: All 13 patients had congenital cataracts, and other ocular abnormalities were found in some cases. Microcornea was found in 12 subjects, and ocular coloboma was observed in five. Various types of coloboma, including iris, choroid, macular, and optic disc, were described. Five mutations in crystallin genes were identified. Four of the mutations are novel: CRYBB1: p.(Arg230Cys), CRYBB2: p.(Gly149Val), CRYGC: p.(Met44CysfsTer59), and CRYGC: p.(Tyr144Ter). One mutation was reported previously: CRYAA: p.(Arg21Trp). Conclusions: We examined a cohort of Chinese patients with congenital cataracts and studied the phenotypes and genotypes. Extralenticular abnormalities, such as microcornea and ocular coloboma, can also be found in patients with congenital cataracts. The phenotype of congenital cataracts associated with macular and optic disc coloboma was reported for the first time in this study. Four novel mutations and one previously reported mutation were identified. These data expand the mutation spectrum in crystallin genes and enhance our understanding of the phenotypes of congenital cataracts.

Rep1 copy number variation is an important genetic cause of choroideremia in Chinese patients.

Choroidermia (CHM) is an X-linked chorioretinal disorder caused by mutations in the Rab Escort Protein 1 (Rep-1) gene. Its diagnosis depends on clinical findings and genetic confirmation; however, mutations in Rep-1 gene are not always detected by standard Sanger sequencing. We therefore conducted multiplex ligation-dependent probe amplification (MLPA) and real-time quantitative PCR (QPCR) in cases of Chinese CHM families in which sequencing all the exons and flanking intronic regions of the CHM gene had not identified a mutation or exons could not be amplified. We hypothesized that copy number variation (CNV) within the Rep-1 gene would explain the etiology of choroideremia in these patients. In the eight unrelated families, exon deletions or duplications were detected by MLPA and QPCR in five. Our results showed CNV within the Rep-1 gene could be an important contributor in Chinese CHM patients. Sequencing of the Rep-1 gene supplemented with MLPA is therefore an important diagnostic strategy in choroideremia patients.

A review of drug-induced liver injury databases.

Drug-induced liver injuries have been a major focus of current research in drug development, and are also one of the major reasons for the failure and withdrawal of drugs in development. Drug-induced liver injuries have been systematically recorded in many public databases, which have become valuable resources in this field. In this study, we provide an overview of these databases, including the liver injury-specific databases LiverTox, LTKB, Open TG-GATEs, LTMap and Hepatox, and the general databases, T3DB, DrugBank, DITOP, DART, CTD and HSDB. The features and limitations of these databases are summarized and discussed in detail. Apart from their powerful functions, we believe that these databases can be improved in several ways: by providing the data about the molecular targets involved in liver toxicity, by incorporating information regarding liver injuries caused by drug interactions, and by regularly updating the data.

Study on the morphology, histology and enzymatic activity of the digestive tract of Gymnocypris eckloni Herzenstein.

The present research was conducted to study the morphology, histology and enzymatic activities of the digestive tract of Gymnocypris eckloni by light and transmission electron microscopes as well as by enzyme assays. The digestive tract of G. eckloni consisted of the oropharyngeal cavity, oesophagus and intestine. The wall of the digestive tract was composed of mucosa, submucosa, muscularis and serosa but lacked muscularis mucosa and glands. The stratified epithelium of the oropharyngeal cavity and oesophagus contained numerous mucous cells. Taste buds were found in the epithelium of the oropharyngeal cavity. A large number of isolated longitudinal striated muscular bundles were present in the submucosa of the oesophagus. The mucosal epithelium of the intestine was composed of simple columnar cells containing absorptive, goblet and endocrine cells. Numerous mitochondria and endoplasmic reticulum were observed in the absorptive cells, especially in the anterior intestine. From the anterior to the posterior intestine, the number and length of mucosal folds and microvilli decreased, but the number of goblet cells increased. The intestinal coefficient was 2.38. Maximum trypsin activity was measured in the anterior intestine, while the lowest lipase and amylase activities were tested in the middle and posterior intestines, respectively. The results provided experimental evidence for evaluating physiological condition of G. eckloni digestive tract, which will be useful for improving current rearing practices and diagnoses of digestive tract diseases.

Mutations in human IFT140 cause non-syndromic retinal degeneration.

Leber congenital amaurosis (LCA) and retinitis pigmentosa (RP) are two genetically heterogeneous retinal degenerative disorders. Despite the identification of a number of genes involved in LCA and RP, the genetic etiology remains unknown in many patients. In this study, we aimed to identify novel disease-causing genes of LCA and RP. Retinal capture sequencing was initially performed to screen mutations in known disease-causing genes in different cohorts of LCA and RP patients. For patients with negative results, we performed whole exome sequencing and applied a series of variant filtering strategies. Sanger sequencing was done to validate candidate causative IFT140 variants. Exome sequencing data analysis led to the identification of IFT140 variants in multiple unrelated non-syndromic LCA and RP cases. All the variants are extremely rare and predicted to be damaging. All the variants passed Sanger validation and segregation tests provided that the family members' DNA was available. The results expand the phenotype spectrum of IFT140 mutations to non-syndromic retinal degeneration, thus extending our understanding of intraflagellar transport and primary cilia biology in the retina. This work also improves the molecular diagnosis of retinal degenerative disease.

[Clinical experiences of semi-sitting astride position for extracorporeal shock wave lithotripsy treatment of urethral calculi].

OBJECTIVE: To explore the therapeutic feasibility, safety and efficacy of semi-sitting astride position for extracorporeal shock wave lithotripsy (SWL) of urethral calculi. METHODS: A total of 7 male cases of urethral calculi from November 1997 to August 2013 were enrolled. Their age range was 24-52 years. There were anterior (n = 1) and posterior (n = 6) urethral calculi. The diameter range of stone was 0.5 cm×0.5 cm to 1.0 cm×2.0 cm. BH-VG twin-pulse low-energy SWL was employed with a semi-sitting astride position. The average frequency was 2 500 (1 800-3 500) times. And the treatment voltage was 3-8 kV. RESULTS: Both stone fragmentation rate and stone-free rate 1 hour post-SWL was 100%.No severe complications occurred. CONCLUSION: Semi-sitting astride position SWL is simple, safe, effective and feasible for posterior urethral calculi.