Stage-specific differences in secretory profile of mesenchymal stromal cells (MSCs) subjected to early- vs late-stage OA synovial fluid

OBJECTIVE

Although, mesenchymal stromal cells (MSCs) are being clinically investigated for their use in osteoarthritis (OA), it is unclear whether their postulated therapeutic properties are equally effective in the early- and late-stages of OA. In this study we investigated MSC cytokine secretion post-exposure to synovial fluid (SF), obtained from early- vs late-stage knee OA patients to justify a potential patient stratification strategy to maximize MSC-mediated treatment effects.

METHOD

Subjects were recruited and categorized into early- [Kellgren-Lawrence (KL) grade I/II, n = 12] and late-stage (KL-III/IV, n = 12) knee OA groups. SF samples were obtained, and their proteome was tested using multiplex assays, after 3-days culture, with and without MSCs. SFs cultured without MSCs were used as a baseline to identify MSC-secreted factors into SFs cultured with MSCs. Linear mixed-effect models and non-parametric tests were used to identify alterations in the MSC secretome during exposure to OA SF (3-days). MSCs cultured for 3-days in 0.5% fetal bovine serum (FBS)-supplemented medium were used to compare SF results with culture medium.

RESULTS

Following exposure to OA SF, the MSC secretome contained proteins that are involved in tissue repair, angiogenesis, chemotaxis, matrix remodeling and the clotting process. However, chemokine (C-X-C motif) ligand-8 (CXCL8; chemoattractant), interleukin-6 (IL6) and chemokine (C-C motif) ligand 2 (CCL2) were elevated in the MSC-secretome in response to early- vs late-stage OA SF.

CONCLUSION

Early- vs late-stage OA SF samples elicit a differential MSC secretome response, arguing for stratification of OA patients to maximize MSC-mediated therapeutic effects.

Substrate elasticity regulates skeletal muscle stem cell self-renewal in culture

Stem cells that naturally reside in adult tissues, such as muscle stem cells (MuSCs), exhibit robust regenerative capacity in vivo that is rapidly lost in culture. Using a bioengineered substrate to recapitulate key biophysical and biochemical niche features in conjunction with a highly automated single-cell tracking algorithm, we show that substrate elasticity is a potent regulator of MuSC fate in culture. Unlike MuSCs on rigid plastic dishes (approximately 10(6) kilopascals), MuSCs cultured on soft hydrogel substrates that mimic the elasticity of muscle (12 kilopascals) self-renew in vitro and contribute extensively to muscle regeneration when subsequently transplanted into mice and assayed histologically and quantitatively by noninvasive bioluminescence imaging. Our studies provide novel evidence that by recapitulating physiological tissue rigidity, propagation of adult muscle stem cells is possible, enabling future cell-based therapies for muscle-wasting diseases.

Return to work after burns: a qualitative research study

As yet no qualitative research studies looking at return to work following burns have been published. The aim of this study was to investigate the "hows" and "whys" of return to work, by purposively selecting a cross-section of burns patients who returned to the same/similar job, those who returned to work but either on a part-time basis or in a different role/job and those who became or remained unemployed, and using semi-structured interviews to explore their experiences. Using matrix analysis methodology, and with the general themes that emerged from these transcripts, it was possible to place patients into 5 broad groups, the "defeated", the "burdened", the "affected", the "unchanged" and the "stronger". We anticipate that use of these general groups will be useful in targeting multi-disciplinary return to work strategies, and discuss how this qualitative research has changed practice at the Queen Victoria Hospital Burns Centre.

The E-Z(easy) clamp--a new instrument to facilitate medial ectropion repair

The medial spindle/retropunctal diamond procedure is a useful technique to correct medial ectropion. Unfortunately, the procedure is difficult, due to the limited size of the surgical field, the bleeding that is seen when the marginal artery is encountered and because of the ever present risk of damaging the canaliculus. We have developed a clamp that overcomes the anatomical opposition outlined above and at the same time improves access to the surgical field.

So much for percentage, but what about the weight?

The use of resuscitation formulae for burns is advocated for A&E departments. Much care is taken to calculate the percentage of the burn, but this is then multiplied by an approximate weight. How accurate is this figure and should it be more carefully measured? Forty two sets of case notes of patients with resuscitation sized burns were reviewed. In 32, a weight was documented in the A&E notes. This was compared with the measured weight on arrival at the burn centre. In half the cases there was a greater than 5 kg difference and in nine patients over 10 kg of difference. The methods of patient weight assessment in 16 A&E departments were reviewed. The majority have only stand on scales. Three departments have sit on scales; however, if they were assessing the weight of a patient who is unable to sit they would need to ask the patient, relatives, or simply guess. Investment in weighing equipment should be encouraged if resuscitation formulae are to have any place in the A&E management of burn patients.

Synchronous reconstruction of the exenterated orbit with a pericranial flap, skin graft and osseointegrated implants

Reconstruction of the exenterated orbit remains a surgical challenge. Here, the authors present a case in which orbital exenteration was performed for an extensive, infiltrating medial canthal basal cell carcinoma; the resulting defect was reconstructed with osseointegrated implants and a pericranial flap onto which a split thickness skin graft was placed. The second stage of the aesthetic rehabilitation of this patient (placement of the transcutaneous abutments) was completed under local anaesthetic 16 weeks later. Subsequently, the patient was fitted with an oculoplastic prosthesis four weeks later. The above technique accelerates the prosthetic rehabilitation of the patient by performing the primary reconstructive procedures simultaneously with the exenteration and by removing the need for secondary surgical procedures under general anaesthetics. The whole process from orbital exenteration to the fitting of an ocular prosthesis was completed in just five months.

Dual prenylation is required for Rab protein localization and function

The majority of Rab proteins are posttranslationally modified with two geranylgeranyl lipid moieties that enable their stable association with membranes. In this study, we present evidence to demonstrate that there is a specific lipid requirement for Rab protein localization and function. Substitution of different prenyl anchors on Rab GTPases does not lead to correct function. In the case of YPT1 and SEC4, two essential Rab genes in Saccharomyces cerevisiae, alternative lipid tails cannot support life when present as the sole source of YPT1 and SEC4. Furthermore, our data suggest that double geranyl-geranyl groups are required for Rab proteins to correctly localize to their characteristic organelle membrane. We have identified a factor, Yip1p that specifically binds the di-geranylgeranylated Rab and does not interact with mono-prenylated Rab proteins. This is the first demonstration that the double prenylation modification of Rab proteins is an important feature in the function of this small GTPase family and adds specific prenylation to the already known determinants of Rab localization.

Anomalous anterior midline cervical tube

Anterior midline cervical anomalies, excepting thyroglossal tract abnormalities, are rare. Two unusual and almost identical cases of an anomalous congenital tube connecting the chin to the upper sternum are described; only one previous similar report exists in the literature. In all three cases, the tubes occurred as isolated anomalies in otherwise healthy children.

FYVE domain targets Pib1p ubiquitin ligase to endosome and vacuolar membranes

Signaling by phosphatidylinositol 3-kinases (PI3Ks) is often mediated by proteins which bind PI3K products directly and are localized to intracellular membranes rich in PI3K products. The FYVE finger domain binds with high specificity to PtdIns3P and proteins containing this domain have been shown to be important components of diverse PI3K signaling pathways. The genome of the yeast Saccharomyces cerevisiae encodes five proteins containing FYVE domains, including Pib1p, whose function is unknown. In addition to a FYVE finger motif, the primary structure of Pib1p contains a region rich in cysteine and histidine residues that we demonstrate binds 2 mol eq of zinc, consistent with this region containing a RING structural domain. The Pib1p RING domain exhibited E2-dependent ubiquitin ligase activity in vitro, indicating that Pib1p is an E3 RING-type ubiquitin ligase. Fluorescence microscopy was used to demonstrate that a GFP-Pib1p fusion protein localized to endosomal and vacuolar membranes and deletional analysis of Pib1p domains indicated that localization of GFP-Pib1p is mediated solely by the FYVE domain. These results suggest that Pib1p mediates ubiquitination of a subset of cellular proteins localized to endosome and vacuolar membranes, and they expand the repertoire of PI3K-regulated pathways identified in eukaryotic cells.

Treatment before transfer: the patient with burns

OBJECTIVES

To review pre-burns centre management, including assessment, resuscitation, and transfer.

METHODS

A retrospective analysis of the notes of all the UK patients admitted to the Burns Centre in 1998, who had a body surface area burn of over 15% in adults (10% in children).

RESULTS

There were 31 patients, 21 adults and 10 children, and the average burn size was 32% (12-96%). Fourteen were overestimated (average of 9%) and 13 underestimated by 7.5%. Twenty nine received intravenous fluids, 18 specified a formula, but it was only applied correctly in 10. The average time to the Burns Centre from the burn was 10 hours, and the time for resuscitation and transfer, eight hours. Documentation was generally poor.

CONCLUSION

There has previously been considerable variation in the standard of initial burn management and there have been problems with burn percentage assessment and resuscitation formula application. A new proforma has been introduced to tackle these issues.

GDP dissociation inhibitor domain II required for Rab GTPase recycling

Rab GTPases are localized to distinct subsets of organelles within the cell, where they regulate SNARE-mediated membrane trafficking between organelles. One factor required for Rab localization and function is Rab GDP dissociation inhibitor (GDI), which is proposed to recycle Rab after vesicle fusion by extracting Rab from the membrane and loading Rab onto newly formed transport intermediates. GDI is composed of two domains; Rab binding is mediated by Domain I, and the function of Domain II is not known. In this study, Domain II of yeast GDI, encoded by the essential GDI1/SEC19 gene, was targeted in a genetic screen to obtain mutants that might lend insight into the function of this domain. In one gdi1 mutant, the cytosolic pools of all Rabs tested were depleted, and Rab accumulated on membranes, suggesting that this mutant Gdi1 protein has a general defect in extraction of Rab from membranes. In a second gdi1 mutant, the endosomal/vacuolar Rabs Vps21/Ypt51p and Ypt7p accumulated in the cytosol bound to Gdi1p, but localization of Ypt1p and Sec4p were not significantly affected. Using an in vitro assay which reconstitutes Gdi1p-mediated membrane loading of Rab, this mutant Gdi1p was found to be defective in loading of Vps21p but not Ypt1p. Loading of Vps21p by loading-defective Gdi1p was restored when acceptor membranes prepared from a deletion strain lacking Vps21p were used. These results suggest that membrane-associated Rab may regulate recruitment of GDI-Rab from the cytosol, possibly by regulating a GDI-Rab receptor. We conclude that Domain II of Gdi1p is essential for Rab loading and Rab extraction, and confirm that each of these activities is required for Gdi1p function in vivo.

Opsite spray: its use for fixation of meshed skin grafts. Simple and low tech

The fixation of skin grafts often poses a problem, particularly in patients who have undergone tangential excision and grafting for burns. Sutures, staples, fibrin glue and other adhesives have been used for graft fixation. We present the use of Opsite spray as a simple method for graft fixation and stabilization. Opsite markedly reduced pain and discomfort at the time of first graft dressing and obviated the necessity for an anaesthetic which is often required for the removal of staples.

Fasciocutaneous blood supply in below-knee amputation

Skin cover after below-knee amputation has been extensively discussed. We describe the flaps which are commonly used and discuss their vascular basis in the context of the current knowledge of the fasciocutaneous system. An understanding of this vascular system will enable surgeons to plan and shape flaps for surgical exposure and coverage.

Cement-related burns

Burns caused by prolonged contact of wet cement with skin are common in this country. Recent literature has highlighted other ways in which the use and manufacture of cement can lead to burn injuries, notably through explosion and contact with hot powder during manufacturing. These injuries are uncommon in this country and potentially very serious. Case studies are presented of two men injured in such a way in the same incident at a cement-manufacturing plant.

Median cleft of the lower lip and mandible: case reports, a new embryologic hypothesis, and subdivision

Median clefts of the lower lip and mandible are rare. In the literature so far, about 62 cases have been described. In addition, three more patients are presented here. These cases show a broad variation in the severity of this deformity, ranging from a simple notch in the vermillion to a complete cleft of the lip involving the tongue, the chin, the mandible, the supporting structures of the median of the neck, and the manubrium sterni. Several hypotheses concerning the pathogenesis of median clefts of the lip and mandible have been proposed. Most authors consider it to be a failure of fusion of the first pair of branchial arches or failure of mesodermal penetration into the midline. From our embryologic point of view, however, instead of paired branchial arches, only one first branchial arch develops during the early embryonic period (< or = 17 mm crown-rump length). Within this first branchial arch, two mandibular processes grow out, separated by a groove in the median. These mandibular processes do not fuse but merge during the late embryonic period (> or = 17 mm to < or = 60 mm crown-rump length). In the same developmental period, there is formation of the lip and the alveolar process and the anlage and outgrowth of one membrane bone center in each mandibular process, resulting in the formation of the mandible with its symphysis. As a consequence of the preceding, we propose the following subdivision of the median clefts of the lip and/or mandible: Hypoplasia of the mandibular processes during the early embryonic period will lead to the severest cleft of the mandible extending into the neck. During the late embryonic period, the less severe median clefts will develop. Disturbances of the outgrowth of bone centers of the mandible, resulting in nonformation of its symphysis, cause clefting of the mandible with involvement of all related soft tissues. Defects in the merging process produce just a notch of the vermilion or a higher cleft of the lower lip with or without involvement of the alveolar process of the mandible. In conclusion, the variety of the clefts in the median of the lower lip and/or mandible as well as the low rate of incidence can be explained by the embryologic hypothesis proposed here.

[Median and paramedian orbito-facial clefts: value of the L-shaped incision in the surgical treatment of nasal deformities]

Authors have reported an interest in the latero-nasal incision for surgical treatment of nasal deformities of patients with median and paramedian orbito-facial clefts. Validity of this "L" approach is correlated to its respect for the integrity of aesthetic facial units and to its position in a natural fold (naso-labial fold). A series of patients with median and paramedian orbito-facial clefts were operated upon using this approach and good results were obtained which support its theoretical value.

Progressive hemifacial atrophy in a patient with lupus erythematosus

This is a single case report describing a young woman with progressive facial atrophy that began at age 15. After she underwent commissuroplasty and collagen injection at age 29, her symptoms continued to progress, and she was ultimately shown to have serologic evidence of systemic lupus. She had a "remission of symptoms" after commencement of medical treatment (chloroquine and topical steroids) for her lupus. The association of progressive hemifacial atrophy and lupus is not new. This case and other cases associated with different autoimmune diseases suggest an autoimmune collagen-vascular origin for some cases of progressive facial atrophy. Furthermore, there is a need to modify the surgical approach in light of concurrent disease.

Clinical evaluation of techniques used in the surgical treatment of progressive hemifacial atrophy

We critically review 13 patients with progressive hemifacial atrophy treated with three basic surgical procedures (free flap transplantation, alloplastic implants, micro-fat injections 'lipofilling') and further ancillary techniques. In spite of the satisfactory results achieved with the procedures, with the exception of alloplasts, we feel that lipofilling may be considered an interesting solution for soft tissue augmentation of the face especially for moderate adipose defects, due to its repeatability, no donor site morbidity, no complications at the recipient site such as lesions resulting from dissection, bleeding, necrosis, etc. This technique can be performed in a day-hospital with short surgery time, at low cost and without a highly skilled team. For severe grades of adipose atrophy, because of the low blood supply to these tissues which interferes with take of any type of autograft, we think that free flaps actually represent one of the best solutions for soft tissue augmentation.

Reshaping of the skull in the early surgical correction of scaphocephaly

It is possible to modify the mathematical patterns of projection geometry to reshape the skull in cranio-facial surgery. The technique of the 'gore-pattern' in accordance with the Hendel procedure changes the shape of individual sections of the skull by changing their radius of curvature. This technique was well known to engineers who built complex structures such as ships, hulls, airfoils and domes. A rigid form of the desired shape is the result to be achieved, which becomes permanent with healing. The gore-pattern is developed by cutting the surface of the sphere along longitudinal lines. Straightening each piece results in a series of elliptical segments referred to as 'gores'. When constructing a sphere from a flat sheet of material, each segment (gore) is bent through 180 degrees and then assembled side-by-side into a sphere. If the gore is cut in the middle, a hemisphere results. Because there are only small areas of contact between the gores, less bending force is necessary to fold a gore-pattern into a sphere than a zone-pattern. The interesting points of this technique, its advantages, and clinical application in the treatment of skull deformity in scaphocephaly are illustrated.

Degloving injuries. A retrospective study at the University Hospital Rotterdam

Degloving injuries are severe and frequently underestimated lesions. In a retrospective study, 65 patients treated between 1985 and 1991 were reviewed. Therapy consisted of surgical exploration as soon after injury as possible, with defatting of the avulsed skin and its replacement on the most functionally important sites. The remaining raw areas were covered with split skin grafts (SSG). This technique reduced morbidity, hospital stay and work incapacity, as compared with patients treated by other methods.

Normal aortoiliac diameters by CT

In spite of the vital role CT plays in the evaluation of vascular disease, no standard CT derived dimensions for the abdominal aorta, iliac, and femoral arteries have been established. A retrospective study of the CT scans of 260 patients was performed with patients separated by sex and age. Aortic diameter was measured at predetermined suprarenal, renal, and infrarenal locations and single measurements of the iliac and femoral arteries were made bilaterally. The vessel diameter was observed to gradually increase with age in both sexes. Men were found to have larger diameter vessels than age matched women. This pattern was noted at all levels measured. The normal range of vascular dimensions determined is presented.

Tumour implantation to a temporalis muscle flap donor site

A rare case of tumour implantation to the donor site of a temporalis muscle flap is described. This flap was used for intra-oral reconstruction following resection of a squamous cell carcinoma of the retromolar fossa. This surprisingly uncommon complication of ablative cancer surgery should largely be preventable by strict adherence to well established surgical principles.