Segregation of COPI-rich and anterograde-cargo-rich domains in endoplasmic-reticulum-to-Golgi transport complexes

AbstractMembrane traffic between the endoplasmic reticulum (ER) and the Golgi complex is regulated by two vesicular coat complexes, COPII and COPI. COPII has been implicated in the selective packaging of anterograde cargo into coated transport vesicles budding from the ER [1]. In mammalian cells, these vesicles coalesce to form tubulo-vesicular transport complexes (TCs), which shuttle anterograde cargo from the ER to the Golgi complex [2–4]. In contrast, COPI-coated vesicles are proposed to mediate recycling of proteins from the Golgi complex to the ER [1,5–7]. The binding of COPI to COPII-coated TCs [3,8,9], however, has led to the proposal that COPI binds to TCs and specifically packages recycling proteins into retrograde vesicles for return to the ER [3,9]. To test this hypothesis, we tracked fluorescently tagged COPI and anterograde-transport markers simultaneously in living cells. COPI predominated on TCs shuttling anterograde cargo to the Golgi complex and was rarely observed on structures moving in directions consistent with retrograde transport. Furthermore, a progressive segregation of COPI-rich domains and anterograde-cargo-rich domains was observed in the TCs. This segregation and the directed motility of COPI-containing TCs were inhibited by antibodies that blocked COPI function. These observations, which are consistent with previous biochemical data [2,9], suggest a role for COPI within TCs en route to the Golgi complex. By sequestering retrograde cargo in the anterograde-directed TCs, COPI couples the sorting of ER recycling proteins [10] to the transport of anterograde cargo

Validation of the German Classification of Diverticular Disease (VADIS)—a prospective bicentric observational study

Purpose: The German Classification of Diverticular Disease was introduced a few years ago. The aim of this study was to determine whether Classification of Diverticular Disease enables an exact stratification of different types of diverticular disease in terms of course and treatment. Methods: This was a prospective, bicentric observational trial. Patients aged ≥ 18 years with diverticular disease were prospectively included. The primary endpoint was the rate of recurrence within 2 year follow-up. Secondary outcome measures were Gastrointestinal Quality of Life Index, Quality of life measured by SF-36, frequency of gastrointestinal complaints, and postoperative complications. Results: A total of 172 patients were included. After conservative management, 40% of patients required surgery for recurrence in type 1b vs. 80% in type 2a/b (p = 0.04). Sixty percent of patients with type 2a (micro-abscess) were in need of surgery for recurrence vs. 100% of patients with type 2b (macro-abscess) (p = 0.11). Patients with type 2a reached 123 ± 15 points in the Gastrointestinal Quality of Life Index compared with 111 ± 14 in type 2b (p = 0.05) and higher scores in the “Mental Component Summary” scale of SF-36 (52 ± 10 vs. 43 ± 13; p = 0.04). Patients with recurrent diverticulitis without complications (type 3b) had less often painful constipation (30% vs. 73%; p = 0.006) when they were operated compared with conservative treatment. Conclusion: Differentiation into type 2a and 2b based on abscess size seems reasonable as patients with type 2b required surgery while patients with type 2a may be treated conservatively. Sigmoid colectomy in patients with type 3b seems to have gastrointestinal complaints during long-term follow-up. Trial registration: https://www.drks.de ID: DRKS0000557

Foveal Cone Structure in Patients With Blue Cone Monochromacy

Purpose: Blue cone monochromacy (BCM) is a rare inherited cone disorder in which both long- (L-) and middle- (M-) wavelength sensitive cone classes are either impaired or nonfunctional. Assessing genotype-phenotype relationships in BCM can improve our understanding of retinal development in the absence of functional L- and M-cones. Here we examined foveal cone structure in patients with genetically-confirmed BCM, using adaptive optics scanning light ophthalmoscopy (AOSLO). / Methods: Twenty-three male patients (aged 6-75 years) with genetically-confirmed BCM were recruited for high-resolution imaging. Eight patients had a deletion of the locus control region (LCR), and 15 had a missense mutation-Cys203Arg-affecting the first two genes in the opsin gene array. Foveal cone structure was assessed using confocal and non-confocal split-detection AOSLO across a 300 × 300 µm area, centered on the location of peak cell density. / Results: Only one of eight patients with LCR deletions and 10 of 15 patients with Cys203Arg mutations had analyzable images. Mean total cone density for Cys203Arg patients was 16,664 ± 11,513 cones/mm2 (n = 10), which is, on average, around 40% of normal. Waveguiding cone density was 2073 ± 963 cones/mm2 (n = 9), which was consistent with published histological estimates of S-cone density in the normal eye. The one patient with an LCR deletion had a total cone density of 10,246 cones/mm2 and waveguiding density of 1535 cones/mm2. / Conclusions: Our results show that BCM patients with LCR deletions and Cys203Arg mutations have a population of non-waveguiding photoreceptors, although the spectral identity and level of function remain unknown

Evaluation of a microbiological screening and acceptance procedure for cryopreserved skin allografts based on 14 day cultures

Viable donor skin is still considered the gold standard for the temporary covering of burns. Since 1985, the Brussels military skin bank supplies cryopreserved viable cadaveric skin for therapeutic use. Unfortunately, viable skin can not be sterilised, which increases the risk of disease transmission. On the other hand, every effort should be made to ensure that the largest possible part of the donated skin is processed into high-performance grafts. Cryopreserved skin allografts that fail bacterial or fungal screening are reworked into ‘sterile’ non-viable glycerolised skin allografts. The transposition of the European Human Cell and Tissue Directives into Belgian Law has prompted us to install a pragmatic microbiological screening and acceptance procedure, which is based on 14 day enrichment broth cultures of finished product samples and treats the complex issues of ‘acceptable bioburden’ and ‘absence of objectionable organisms’. In this paper we evaluate this procedure applied on 148 skin donations. An incubation time of 14 days allowed for the detection of an additional 16.9% (25/148) of contaminated skin compared to our classic 3 day incubation protocol and consequently increased the share of non-viable glycerolised skin with 8.4%. Importantly, 24% of these slow-growing microorganisms were considered to be potentially pathogenic. In addition, we raise the issue of ‘representative sampling’ of heterogeneously contaminated skin. In summary, we feel that our present microbiological testing and acceptance procedure assures adequate patient safety and skin availability. The question remains, however, whether the supposed increased safety of our skin grafts outweighs the reduced overall clinical performance and the increase in work load and costs

Renal transplantation in children managed with lymphocyte depleting agents and low-dose maintenance tacrolimus monotherapy

OBJECTIVE. Describe the safety and efficacy of antithymocyte globulin or alemtuzumab preconditioning, steroid avoidance and reduced calcineurin inhibitor (CNI) immunosuppression in 34 children undergoing renal transplantation. METHODS. ATG (n=8) or alemtuzumab (n=26) were infused at the time of transplantation. This was followed by low-dose twice a day tacrolimus monotherapy with consolidation to once daily dosing by 6 months and once every other day dosing by 12 months. Follow-up ranged from 0.5-2.9 years (mean 1.33 years), with a minimum of 6 months. RESULTS. Both ATG and alemtuzumab were well tolerated. Lymphopenia occurred routinely and resolved after 3-6 months. Acute cellular rejection occurred in 9%; it was related to medical nonadherence in two patients and resulted in one graft loss at 1.5 years. Important adverse events included transient neutropenia in 10 children (none with serious infection), and autoimmune hemolytic anemia in two (resolved with a steroid course in both and conversion to sirolimus in one). Estimated glomerular filtration rate (e-GFR) was stable and averaged 88 mL/min/1.73 m at latest follow-up. Fifteen preadolescents had a greater increase in height Z-score at 1 year (1.3 vs. 0.5, P=0.001), and a higher e-GFR (94.8±21 vs. 76.6±20 ml/min/1.73 m, P<0.05), when compared to case-matched historical controls who were weaned off steroids by 6 months after transplantation and received twice daily tacrolimus monotherapy. CONCLUSION. This simple regimen appears safe, has a low risk for acute cellular rejection or other adverse effects, and is associated with excellent growth and renal function. Such a regimen may also improve compliance and limit CNI nephrotoxicity. © 2007 Lippincott Williams & Wilkins, Inc