Long-Residence Time Peptide Antagonist for the Vasopressin V2 Receptor to Treat Autosomal Dominant Polycystic Kidney Disease.

The dysregulated intracellular cAMP in the kidneys drives cystogenesis and progression in autosomal dominant polycystic kidney disease (ADPKD). Mounting evidence supports that vasopressin V2 receptor (V2R) antagonism effectively reduces cAMP levels, validating this receptor as a therapeutic target. Tolvaptan, an FDA-approved V2R antagonist, shows limitations in its clinical efficacy for ADPKD treatment. Therefore, the pursuit of better-in-class V2R antagonists with an improved efficacy remains pressing. Herein, we synthesized a set of peptide V2R antagonists. Peptide 33 exhibited a high binding affinity for the V2R (Ki = 6.1 ± 1.5 nM) and an extended residence time of 20 ± 1 min, 2-fold that of tolvaptan. This prolonged interaction translated into sustained suppression of cAMP production in washout experiments. Furthermore, peptide 33 exhibited improved efficacies over tolvaptan in both ex vivo and in vivo models of ADPKD, underscoring its potential as a promising lead compound for the treatment of ADPKD.

Fujian cytoplasmic male sterility and the fertility restorer gene OsRf19 provide a promising breeding system for hybrid rice.

Cytoplasmic male sterility (CMS) determined by mitochondrial genes and restorer of fertility (Rf) controlled by nuclear-encoded genes provide the breeding systems of many hybrid crops for the utilization of heterosis. Although several CMS/Rf systems have been widely exploited in rice, hybrid breeding using these systems has encountered difficulties due to either fertility instability or complications of two-locus inheritance or both. In this work, we characterized a type of CMS, Fujian Abortive cytoplasmic male sterility (CMS-FA), with stable sporophytic male sterility and a nuclear restorer gene that completely restores hybrid fertility. CMS is caused by the chimeric open reading frame FA182 that specifically occurs in the mitochondrial genome of CMS-FA rice. The restorer gene OsRf19 encodes a pentatricopeptide repeat (PPR) protein targeted to mitochondria, where it mediates the cleavage of FA182 transcripts, thus restoring male fertility. Comparative sequence analysis revealed that OsRf19 originated through a recent duplication in wild rice relatives, sharing a common ancestor with OsRf1a/OsRf5, a fertility restorer gene for Boro II and Hong-Lian CMS. We developed six restorer lines by introgressing OsRf19 into parental lines of elite CMS-WA hybrids; hybrids produced from these lines showed equivalent or better agronomic performance relative to their counterparts based on the CMS-WA system. These results demonstrate that CMS-FA/OsRf19 provides a highly promising system for future hybrid rice breeding.

Multiple variants in UGT1A1 gene are factors to develop indirect hyper-bilirubinemia.

Most Taiwanese patients with hyper-bilirubinemia have genetic abnormalities in the uridine diphosphoglucuronate-glucuronosyltransferase 1A1 (UGT1A1) gene beyond the variants in the TATA box upstream of UGT1A1 associated with Gilbert's syndrome. To investigate the role of UGT1A1 in the pathogenesis of indirect hyper-bilirubinemia, we prospectively studied 97 consecutive patients with indirect hyper-bilirubinemia for genotypes of promoter [(TA)6TAA6, (TA)7TAA7] and coding region [nucleotide (nt)-211, nt-686, nt-1,091 and nt-1,456] of UGT1A1. Thirty-six of the patients (45.6%) were found to have Gilbert's syndrome with 7/7 genotype; among them, 14 also carried variants at nt-686. Forty-two patients (43.3%) had the 6/7 genotype; among them, 36 patients were found to have one or more variants in the coding region. Patients with higher serum total bilirubin are associated with higher likelihood of carrying Gilbert's syndrome genotype: 60.0% (P=0.007) patients with serum total bilirubin level ≥2.5 mg/dL carried the Gilbert's syndrome genotype, while only 23.9% of patients with serum total bilirubin level <2.5 mg/dL carry the same genotype (P=0.0006). Forty-one of the 61 non-Gilbert's patients had one homogenous variants or two or more heterozygous variants in UGT1A1. Further studies are necessary to confirm the role of one homo-zygous variant or two or more hetero-zygous variants in UGT1A1 gene as factors for indirect hyper-bilirubinemia.

System approach to prevent common bile duct injury and enhance performance of laparoscopic cholecystectomy.

Experience collected from 5200 cases of laparoscopic cholecystectomy (LC) and 29 patients (6 ours, 23 referred) with major common bile duct (CBD) injury during LC in our institute between December 1990 and July 2004 was reported to demonstrate that the system approach we applied in performing LC prevents CBD injury and enhances surgical performance. Each case of CBD injury was meticulously analyzed to identify causative factors. We developed preventive strategies focusing on 4 dimensions: patient, environment, procedure, and operator. Surgical performance was then evaluated to demonstrate improvements. Incidence of CBD injury was calculated for early and latter halves of the series to compare 5 parameters of surgical performance: patient selection, operation time, indwelling drainage tube, surgeon, and conversion rate. Results of accident analysis demonstrated that CBD injury followed definite mechanisms; several warning signs appearing before and during injury were identified and classified. According to these results, we designed strategies to prevent injury, including: setting up patient-selection program, controlling surgical environment, developing error-proof procedures, and constructing training programs. Incidence of CBD injury in the whole series was 0.12% (6/5200), 0.27% in early half (6/2224), and zero (0/2967) in latter half. Attending doctors had significantly shorter operation times in latter period for both elective and emergent LC. Rate of using drainage tubes for elective surgery by attending doctors was significantly decreased in latter period. Operation time for elective surgery by residents was similar in both early and latter periods. However, residents in latter period had longer operation times (around 23 min long, P<0.001) for emergent LC. Steps of our system approach include: (1) detailed accident analysis focusing on patient, environment, procedure, and surgeon; (2) developing 4 strategies directly responding to accident analysis results, including proper patient selection, control of environment, error-proof procedures, and a well-designed training program; and (3) demonstrating improved patient safety and surgical performance. Consistent use of systems approach promises continuing quality improvement. We believe our working model will help perform safer LC and also benefit other medical disciplines.

Laparoscopic common bile duct exploration with T-tube choledochotomy for the management of choledocholithiasis.

Although laparoscopic cholecystectomy (LC) has become the gold standard for the management of gallstone disease, the application of laparoscopic common bile duct exploration (LCBDE) for choledocholithiasis has been slower. The aim of this study is to determine the feasibility and effectiveness of LCBDE. A retrospective cohort study was conducted to compare LCBDE (n = 82) with conventional common bile duct exploration (CCBDE) (n = 75) and endoscopic sphincterotomy (EST) (n = 80) in the management of choledocholithiasis. All our LCBDEs were performed through choledochotomy with T-tube placement. The mean operative time of the LCBDE group (124 +/- 48 minutes) was not significantly longer then the CCBDE group (118 +/- 35 minutes), while the postoperative hospitalization was shorter in both the LCBDE (8 +/- 5 days) and EST (9 +/- 4 days) groups than in the CCBDE (13 +/- 6 days) group. In the LCBDE group, 14 patients (17.1%) required postoperative choledochoscopy to clear residual stones through the T-tube tract. The only mortality occurred in the CCBDE group. The morbidity rate was 3.7% (3/82) in the LCBDE group, including bile leakage in 1 case and bile peritonitis in 2 cases; 6.7% (5/75) in the CCBDE group, including atlectasis in 2 cases, sepsis in 1, and wound infection in 2. There were 2 cases of postoperative pancreatitis (2.5%; 2/80) in the EST group. The difference in the average number of sessions needed for complete clearance of choledocholithiasis in each group was statistically significant (EST, 1.46 +/- 0.67; LCBDE, 1.23 +/- 0.42; and CCBDE, 1.09 +/- 0.28; P < 0.0001). Our results suggested that EST and LCBDE tended to require more therapeutic sessions then CCBDE, although these sessions were less invasive. The benefits of LCBDE include minimal invasiveness, concurrent treatment of gallbladder stone and CBD stones in a single session, and a shorter postoperative hospital stay. However a longer learning curve is needed. Selection of the most suitable therapeutic option for individual patients by an experienced surgeon gives the most benefits to patients.

Management of bile leakage after laparoscopic cholecystectomy based on etiological classification.

PURPOSE: To analyze and classify bile leakage after laparoscopic cholecystectomy (LC) according to its etiology. This classification will help to determine the most appropriate management strategy, whereby unnecessary intervention can be avoided. METHODS: We examined the medical records of 16 patients in whom bile leakage occurred as a complication of LC. RESULTS: Bile leakage was classified according to its cause into the following groups: insecure closure of the cystic duct stump (n = 3); retention of a common bile duct (CBD) stone (n = 1); CBD injury (n = 10); unsuspected accessory bile ducts (n = 1); and unknown origin (n = 1). The management strategies included observation (n = 3), laparoscopic intervention with drainage (n = 4), laparotomy with drainage (n = 3), and laparotomy with Roux-en-Y choledochojejunostomy for CBD transection (n = 6). All 16 patients recovered uneventfully with similar hospitalization. CONCLUSIONS: Bile leakage is not always caused by bile duct injury, and it would be inappropriate to attribute leakage to bile duct injury if there is a retained CBD stone, an unsuspected accessory duct, or an unsecured cystic duct stump. Thus, the management of each condition should vary accordingly. Reviewing a videotape of the surgery and early cholangiogram can help to establish the etiological diagnosis and select the most appropriate course of action.