Insect cells of Spodoptera frugiperda support WSSV gene replication but not progeny virion assembly.

The lacking of stable and susceptible cell lines has hampered research on pathogenic mechanism of crustacean white spot syndrome virus (WSSV). To look for the suitable cell line which can sustain WSSV infection, we performed the studies on WSSV infection in the Spodoptera frugiperda (Sf9) insect cells. In consistent with our previous study in vitro in crayfish hematopoietic tissue cells, the WSSV envelope was detached from nucleocapsid around 2 hpi in Sf9 cells, which was accompanied with the cytoplasmic transport of nucleocapsid toward the cell nucleus within 3 hpi. Furthermore, the expression profile of both gene and protein of WSSV was determined in Sf9 cells after viral infection, in which a viral immediate early gene IE1 and an envelope protein VP28 exhibited gradually increased presence from 3 to 24 hpi. Similarly, the significant increase of WSSV genome replication was found at 3-48 hpi in Sf9 cells after infection with WSSV, indicating that Sf9 cells supported WSSV genome replication. Unfortunately, no assembled progeny virion was observed at 24 and 48 hpi in Sf9 cell nuclei as determined by transmission electron microscope, suggesting that WSSV progeny could not be assembled in Sf9 cell line as the viral structural proteins could not be transported into cell nuclei. Collectively, these findings provide a cell model for comparative analysis of WSSV infection mechanism with crustacean cells.

The crustacean DNA virus tegument protein VP26 binds to SNAP29 to inhibit SNARE complex assembly and autophagic degradation.

Autophagy generally functions as a cellular surveillance mechanism to combat invading viruses, but viruses have evolved various strategies to block autophagic degradation and even subvert it to promote viral propagation. White spot syndrome virus (WSSV) is the most highly pathogenic crustacean virus, but little is currently known about whether crustacean viruses such as WSSV can subvert autophagic degradation for escape. Here, we show that even though WSSV proliferation triggers the accumulation of autophagosomes, autophagic degradation is blocked in the crustacean species red claw crayfish. Interestingly, the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex including CqSNAP29, CqVAMP7, and the novel autophagosome SNARE protein CqSyx12 is required for autophagic flux to restrict WSSV replication, as revealed by gene silencing experiments. Simultaneously, the expressed WSSV tegument protein VP26, which likely localizes on autophagic membrane mediated by its transmembrane region, binds the Qb-SNARE domain of CqSNAP29 to competitively inhibit the binding of CqSyx12-Qa-SNARE with CqSNAP29-Qb-SNARE; this in turn disrupts the assembly of the CqSyx12-SNAP29-VAMP7 SNARE complex, which is indispensable for the proposed fusion of autophagosomes and lysosomes. Consequently, the autophagic degradation of WSSV is likely suppressed by the expressed VP26 protein in vivo in crayfish, thus probably protecting WSSV components from degradation via the autophagosome-lysosome pathway, resulting in evasion by WSSV. Collectively, these findings highlight how a DNA virus can subvert autophagic degradation by impairing the assembly of the SNARE complex to achieve evasion, paving the way for understanding host-DNA virus interactions from an evolutionary point of view, from crustaceans to mammals.IMPORTANCEWhite spot syndrome virus (WSSV) is one of the largest animal DNA viruses in terms of its genome size and has caused huge economic losses in the farming of crustaceans such as shrimp and crayfish. Detailed knowledge of WSSV-host interactions is still lacking, particularly regarding viral escape from host immune clearance. Intriguingly, we found that the presence of WSSV-VP26 might inhibit the autophagic degradation of WSSV in vivo in the crustacean species red claw crayfish. Importantly, this study is the first to show that viral protein VP26 functions as a core factor to benefit WSSV escape by disrupting the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, which is necessary for the proposed fusion of autophagosomes with lysosomes for subsequent degradation. These findings highlight a novel mechanism of DNA virus evasion by blocking SNARE complex assembly and identify viral VP26 as a key candidate for anti-WSSV targeting.

Demystifying Palmar Midcarpal Instability.

Palmar midcarpal instability is an uncommon condition diagnosed clinically with a painful pathognomonic clunk on terminal ulnar deviation of the wrist. Various causes have been described, but congenital laxity of the carpal ligaments is thought to be a key contributor. Treatment commences with conservative measures. This includes proprioceptive training based on more recent concepts on the sensorimotor function of the wrist. When these measures plateau, surgery is considered. The lack of high-level evidence and consensus on its cause continue to hamper our understanding and knowledge of this condition. The purpose of this review is to examine the current evidence to conceptualize this mysterious, yet infrequent phenomenon, and to provide an algorithm on its management.

A comparison between free gracilis muscle flap and pedicled pectoralis major flap reconstructions following salvage laryngectomy.

INTRODUCTION: Muscle flaps are often used in the prevention and treatment of pharyngocutaneous fistula following total salvage laryngectomy in the setting of chemo-radiated neck for laryngeal carcinomas. We report our experience with the gracilis free muscle flap compared to the pedicled pectoralis major for the prophylaxis of fistula formation. METHODS: Forty-nine patients with radio-recurrent laryngeal carcinoma over ten years who underwent salvage laryngectomy and either immediate free gracilis (22 patients) or pedicled pectoralis major muscle flap (27 patients) reconstruction were reviewed. RESULTS: There were 12 complications in pectoralis major flap group and eight in gracilis flap group. Most of these occurred early in the post-operative period. These were related to poor wound healing with the pectoralis major flap reconstructions. Fistulation rates were similar in the two groups (Pectoralis major: 6/27, gracilis: 5/22). CONCLUSIONS: In our experience, the gracilis free muscle flap is a good reconstructive option in the prevention of pharyngocutaneous fistula formation following salvage laryngectomies. It is at least equivalent to a pectoralis muscle flap in the prevention of fistulae, but we prefer the gracilis for many reasons, including ease of harvest and preservation of the pectoralis major flap for future reconstructions.

Distraction for proximal interphalangeal joint contractures: long-term results.

PURPOSE: To report the medium- to long-term outcomes of joint distraction using a unilateral external fixator in the treatment of chronic post-traumatic proximal interphalangaeal (PIP) joint contractures. METHOD: Between September 2001 and October 2011, 94 consecutive patients (98 PIP joints) with a mean age of 43 years (range, 17-69 y) were treated with external fixation for chronic flexion deformity of the PIP joint from trauma. The average time from injury to surgery was 48 months (range, 6-84 mo), and the duration of joint distraction was 10 days (range, 7-22 d). Patients were followed for a mean period of 54 months (range, 12-72 mo). RESULTS: The average gain in joint flexion was 25° and in joint extension was 40°. The mean improvement in the active range of movement was 67° (range. 30°-90°). There was no loss of motion on the latest follow-up. Patients younger than 40 years fared slightly better than those older than 40 years. Two patients developed swelling, pain, and erythema during treatment, which resolved upon temporarily stopping the distraction process. There were 12 cases of superficial pin-site infections, which were managed conservatively without serious complications or adverse outcome. CONCLUSIONS: External fixation is a simple and effective treatment modality for chronic traumatic PIP joint contractures with good predictable medium- to long-term results. Careful patient selection and monitoring are required.

Management of posttraumatic proximal interphalangeal joint contracture.

Chronic flexion contracture of the proximal interphalangeal (PIP) joint presents a common yet challenging problem to hand surgeons. Over the years, multiple treatment modalities have been described for this problem, producing limited results. Nonoperative treatment using serial casting and splints should be tried before attempting open surgical release, which should be done in selected patients. The use of external fixation for treating PIP contracture has been encouraging and can be a useful alterative. This review provides an update on the current management of PIP joint contractures and presents a flowchart of treatment to aid decision making.

Treatment of Rolando fracture by capsuloligamentotaxis using mini external fixator: a report of 16 cases.

Treatment of Rolando fractures remains a challenge for hand surgeons. We present a case series of 16 comminuted Rolando type fractures treated by controlled capsuloligamentous distraction (and over distraction by 2 mm) using the Pennig mini-external fixation system. Additional Kirschner wire(s) were used to maintain fracture reduction and stability. Average time of injury to surgery time was five days. Mean age of patients was 26 years. The mean follow-up was 20 months. Excellent fracture union was achieved in all cases. All except two patients were pain free at the final consultation. The mean grip and pinch strength of the affected thumb was 96% and 93%, respectively, of the unaffected thumb with a minimal loss of movements. This technique is simple and effective. It enables immediate mobilisation of the unaffected joints and prevents stiffness. We recommend this distraction technique for the treatment of significantly comminuted Rolando type fractures.

Cutaneous horn: case report.

We report an interesting case of a large, rapidly developing cutaneous horn in the temple area of an 86-year-old man who was admitted to a hospital in London. The lesion had been caused by a squamous cell carcinoma. We highlight the historical and pathophysiological aspects of the condition and draw attention to the malignant potential of such lesions.