The ctpA gene encodes the C-terminal processing protease for the D1 protein of the photosystem II reaction center complex.

The D1 protein of the photosystem II (PSII) complex in the thylakoid membrane of oxygenic photosynthetic organisms is synthesized as a precursor polypeptide (pD1) with a C-terminal extension. Posttranslational processing of the pD1 protein is essential to establish water oxidation activity of the PSII complex. We have recently identified a gene, ctpA, a mutation in which resulted in a loss of PSII activity in the cyanobacterium Synechocystis sp. PCC 6803. To study the function of the CtpA protein, we inactivated the ctpA gene by inserting a kanamycin-resistance gene into its coding sequence. The resultant mutant strain, T564, had no PSII-mediated water oxidation activity, but it had normal cytochrome b6f and photosystem I activities. Measurements of thermoluminescence profiles and rates of reduction of 2,6-dichlorophenolindophenol indicated that PSII complexes in the mutant cells had functional reaction centers that were unable to accept electrons from water. Immunoblot analysis showed that D1, D2, CP47, CP43, and the alpha subunit of cytochrome b559, five integral membrane proteins of PSII, were present in T564 cells. Interestingly, the D1 protein in the mutant cells was 2 kDa larger than that in wild-type cells, due to the presence of a C-terminal extension. We conclude that the CtpA protein is a processing enzyme that cleaves off the C-terminal extension of the D1 protein. Interestingly, the CtpA protein shows significant sequence similarity to the interphotoreceptor retinoid-binding proteins in the bovine, human, and insect eye systems.     

A Novel Non-Invasive Adjuvant Biomechanical Treatment for Patients with Altered Rehabilitation after Total Knee Arthroplasty: Results of a Pilot Investigation

Background

Many factors contribute to suboptimal results after total knee arthroplasty (TKA) but little is known regarding the value of postsurgical rehabilitation after TKA. We examined the effects of an enhanced closed kinematic chain exercises program (AposTherapy) on gait patterns and clinical outcomes among patients with a lack of progress in their postsurgical rehabilitation.

Methods

Twenty-two patients were prospectively followed during the study. Gait spatiotemporal parameters were measured at the initial evaluation, after 15 minutes of therapy, and after 3 months of therapy. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the short form (SF) 36 health survey were completed by patients before treatment and after 3 months of treatment.

Results

The WOMAC and SF-36 scores improved significantly after 3 months of treatment. Gait velocity, single limb support, and step length of the operated leg improved significantly even after a single 15 minutes treatment. Normal gait velocity was observed in 36% of patients after 3 months of treatment.

Conclusions

A physiotherapy program that included enhanced closed kinematic chain biomechanical therapy was beneficial for patients who experienced a suboptimal rehabilitation course after TKA.     

Experience with lamivudine therapy for hepatitis B virus infection before and after liver transplantation,and review of the literature

OBJECTIVES: To analyse the results of lamivudine therapy on suppression of hepatitis B virus (HBV) replication before transplantation and on preventing graft reinfection postoperatively. DESIGN: Long-term clinical study. SETTING: Liver Institute and Department of Transplantation of a tertiary-care university-affiliated centre. SUBJECTS: (1) 14 candidates for liver transplantation with decompensated liver disease caused by active replication of HBV; (2) six patients with recurrent HBV infection after transplantation. INTERVENTION: Lamivudine 100 mg daily; administered in group 1 before surgery and continued after in nine patients who underwent transplantation; administered in group two postoperatively only. anti-hepatitis B surface antigen immunoglobulin (HBIg) was administered postoperatively in both groups. MAIN OUTCOME MEASURES: Immunoassay evaluation of serum hepatitis B surface antigen, serum hepatitis Be antigen and serum HBV DNA (hybridization and PCR); sequencing through the tyrosine-methionine-aspartate-aspartate locus of the HBV polymerase gene in patients with lamivudine breakthrough; inflammation and fibrosis scoring on liver biopsy before and at least 2 years after lamivudine therapy in group 2. RESULTS: Pretransplantation therapy (group 1) significantly suppressed HBV replication and enabled nine patients (64.2%) to undergo transplantation. Only one patient (7.1%) had lamivudine breakthrough, and one (7.1%) had recurrent HBV. Lamivudine administration begun after transplantation (mean 48.0 months, range 30-60 months) because of graft reinfection (group 2) was associated, over the long-term, with the emergence of high mutation rates (83.3%), histological disease progression (66.6%), and hepatic failure (33.3%). CONCLUSIONS: In patients with chronic HBV infection and active viral replication, lamivudine therapy is effective when started before transplantation. However, its long-term administration after transplantation for recurrent HBV leads to high resistance rates. Combination therapy with lamivudine and HBIg immunoglobulin can substantially reduce the recurrence rate. Further studies on combination antiviral therapy are needed in this patient population.     

ICO Amplicon NGS Data Analysis: A Web Tool for Variant Detection in Common High‐Risk Hereditary Cancer Genes Analyzed by Amplicon GS Junior Next‐Generation Sequencing

Next‐generation sequencing (NGS) has revolutionized genomic research and is set to have a major impact on genetic diagnostics thanks to the advent of benchtop sequencers and flexible kits for targeted libraries. Among the main hurdles in NGS are the difficulty of performing bioinformatic analysis of the huge volume of data generated and the high number of false positive calls that could be obtained, depending on the NGS technology and the analysis pipeline. Here, we present the development of a free and user‐friendly Web data analysis tool that detects and filters sequence variants, provides coverage information, and allows the user to customize some basic parameters. The tool has been developed to provide accurate genetic analysis of targeted sequencing of common high‐risk hereditary cancer genes using amplicon libraries run in a GS Junior System. The Web resource is linked to our own mutation database, to assist in the clinical classification of identified variants. We believe that this tool will greatly facilitate the use of the NGS approach in routine laboratories.     

Inflammatory bowel disease: An increased risk factor for neurologic complications

Only a very few systematic studies have investigated the frequency of neurologic disorders in patients with Crohn’s disease(CD) and ulcerative colitis(UC), which are the two main types of inflammatory bowel disease(IBD). Results have been inconsistent and variable, owing to differences in case-finding methods and evaluated outcomes in different studies. The most frequent neurologic manifestations reported in CD and UC populations are cerebrovascular disease(with either arterial or venous events), demyelinating central nervous system disease, and peripheral neuropathy(whether axonal or demyelinating); however, the literature describes numerous nervous system disorders as being associated with IBD. The pathogenesis of nervous system tissue involvement in IBD has yet to be elucidated, although it seems to be related to immune mechanisms or prothrombotic states. The recently-introduced tumor necrosis factor(TNF) inhibitors have proven successful in controlling moderate to severe IBD activity. However, severe neurologic disorders associated with TNF inhibitors have been reported, which therefore raises concerns regarding the effect of anti-TNF-α antibodies on the nervous system. Although neurological involvement associated with IBD is rarely reported, gastroenterologists should be aware of the neurologic manifestations of IBD in order to provide early treatment, which is crucial for preventing major neurologic morbidity.