Aldehyde perception induces specific molecular responses in Laminaria digitata and affects algal consumption by a specialist grazer

In the marine environment, distance signaling based on water-borne cues occurs during interactions between macroalgae and herbivores. In the brown alga Laminaria digitata from North-Atlantic Brittany, oligoalginates elicitation or grazing was shown to induce chemical and transcriptomic regulations, as well as emission of a wide range of volatile aldehydes, but their biological roles as potential defense or warning signals in response to herbivores remain unknown. In this context, bioassays using the limpet Patella pellucida and L. digitata were carried out for determining the effects of algal transient incubation with 4-hydroxyhexenal (4-HHE), 4-hydroxynonenal (4-HNE) and dodecadienal on algal consumption by grazers. Simultaneously, we have developed metabolomic and transcriptomic approaches to study algal molecular responses after treatments of L. digitata with these chemical compounds. The results indicated that, unlike the treatment of the plantlets with 4-HNE or dodecadienal, treatment with 4-HHE decreases algal consumption by herbivores at 100 ng.ml-1 . Moreover, we showed that algal metabolome was significantly modified according to the type of aldehydes, and more specifically the metabolite pathways linked to fatty acid degradation. RNAseq analysis further showed that 4-HHE at 100 ng.ml-1 can activate the regulation of genes related to oxylipin signaling pathways and specific responses, compared to oligoalginates elicitation. As kelp beds constitute complex ecosystems consisting of habitat and food source for marine herbivores, the algal perception of specific aldehydes leading to targeted molecular regulations could have an important biological role on kelps/grazers interactions.

Alginates along the filament of the brown alga Ectocarpus help cells cope with stress

Ectocarpus is a filamentous brown alga, which cell wall is composed mainly of alginates and fucans (80%), two non-crystalline polysaccharide classes. Alginates are linear chains of epimers of 1,4-linked uronic acids, β-D-mannuronic acid (M) and α-L-guluronic acid (G). Previous physico-chemical studies showed that G-rich alginate gels are stiffer than M-rich alginate gels when prepared in vitro with calcium. In order to assess the possible role of alginates in Ectocarpus, we first immunolocalised M-rich or G-rich alginates using specific monoclonal antibodies along the filament. As a second step, we calculated the tensile stress experienced by the cell wall along the filament, and varied it with hypertonic or hypotonic solutions. As a third step, we measured the stiffness of the cell along the filament, using cell deformation measurements and atomic force microscopy. Overlapping of the three sets of data allowed to show that alginates co-localise with the stiffest and most stressed areas of the filament, namely the dome of the apical cell and the shanks of the central round cells. In addition, no major distinction between M-rich and G-rich alginate spatial patterns could be observed. Altogether, these results support that both M-rich and G-rich alginates play similar roles in stiffening the cell wall where the tensile stress is high and exposes cells to bursting, and that these roles are independent from cell growth and differentiation.

Lethal form of spinocerebellar ataxia type 7 with early onset in childhood

Progressive cerebellar ataxias are well-known hereditary neurological disorders. Among them, spinocerebellar ataxia type 7 (SCA7) is inherited as an autosomal dominant trait and is ascribed to the expansion of a CAG trinucleotide repeat within the ATXN7 gene. An anticipation phenomenon can occur during paternal transmission and sometimes is responsible for a severe infantile form. The specificity of SCA7 is the retinal involvement with retinitis pigmentosa and cone rod dystrophy. We describe a familial form with two siblings who died of a severe infantile form. Diagnosis was made in their father, who had a recent history of macular atrophy and presented with gait disturbance thereafter. Retrospectively, substantial triplet repeat expansion was confirmed in the two affected infants. These infantile forms are rare and difficult to diagnose in the absence of suggestive family symptoms.

[Infantile pyknocytosis: A cause of noenatal hemolytic anemia. Is recombinant erythropoietin an alternative to transfusion?]

Infantile pyknocytosis is a neonatal hemolytic disorder which causes anemia and icterus and is characterized by the presence of an increased number of distorted red blood cells called pyknocytes. Resolution spontaneously occurs in the first semester of life. It has been generally described as a rare entity, with an occasional family history. We report seven cases of infantile pyknocytosis observed in our hospital in 3 years. Most of the infants presented with hemolytic icterus and profound anemia that was reaching its peak by the 3rd week of life. Three neonates received one to three red blood cell transfusions, according to former recommendations. However, the following four received a treatment with recombinant erythropoietin administered subcutaneously. Only one of these four cases required a transfusion. All of them were free of hematological disease 2-3 months after completion of treatment. Infantile pyknocytosis is a recognized cause of neonatal hemolytic anemia, which requires careful examination of red cell morphology on a peripheral blood smear. The cause of this transient disorder remains unknown. Our observations show that recombinant erythropoietin therapy is effective in treating infantile pyknocytosis and increases the reticulocyte response, thus improving the hemoglobin level.

Production of genetically and developmentally modified seaweeds: exploiting the potential of artificial selection techniques

Plant feedstock with specific, modified developmental features has been a quest for centuries. Since the development and spread of agriculture, there has been a desire for plants producing disproportionate-or more abundant and more nutritional-biomass that meet human needs better than their native counterparts. Seaweed aquaculture, targeted for human consumption and the production of various raw materials, is a rapidly expanding field and its stakeholders have increasing vested interest for cost-effective and lucrative seaweed cultivation processes. Thus, scientific research on seaweed development is particularly timely: the potential for expansion of seaweed cultivation depends on the sector's capacity to produce seaweeds with modified morphological features (e.g., thicker blades), higher growth rates or delayed (or even no) fertility. Here, we review the various technical approaches used to modify development in macroalgae, which have attracted little attention from developmental biologists to date. Because seaweed (or marine macroalgae) anatomy is much less complex than that of land plants and because seaweeds belong to three different eukaryotic phyla, the mechanisms controlling their morphogenesis are key to understanding their development. Here, we present efficient sources of developmentally and genetically modified seaweeds-somatic variants, artificial hybrids and mutants-as well as the future potential of these techniques.

Treatment of chronic Achilles tendon rupture by shortening suture and free sural triceps aponeurosis graft

INTRODUCTION

The Bosworth technique is old but still widely used. It involves problems of precisely determining the length of the Achilles tendon and of a volume effect in the turndown area.

HYPOTHESIS

A new reconstruction technique is assessed, based on free sural triceps aponeurosis transfer without turndown, associated to tendon shortening suture.

MATERIALS AND METHODS

Twenty-three patients were assessed by AOFAS score and clinical examination (plus MRI in 14 cases) at a mean 24.5 months' follow-up. Mean age was 52.1 years. Mean pre-operative AOFAS score was 63.6/100.

RESULTS

Mean postoperative AOFAS score was 96.1. Mean graft length was 7.5 cm. Surgical revision was required for one case of postoperative infection. Twelve patients resumed leisure sports at their previous level by a mean 9.4 ± 2 months; three competitive sportsmen resumed sport at their previous level by a mean 7.6 months. None were dissatisfied or disappointed with their operation. MRI performed at 1 year found increased tendon volume without abnormality in 57% of cases; 43% showed abnormal images.

DISCUSSION

Functional results were comparable to literature reports. It can be difficult to determine Achilles length for the Bosworth technique: this is made easier by conserving a fibrous support of a length determined with reference to the healthy side. The technique avoids aponeurosis turndown, and thus avoids the problem of plasty volume effect. The two cases of cutaneous complication occurred in the two most elderly patients, raising the question of the indications for reconstructive surgery in the elderly. The abnormalities found on MRI concerned scar tissue remodeling in patients with good or excellent clinical results.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Anterior cruciate ligament reconstruction with fascia lata using a minimally invasive arthroscopic harvesting technique

Anterior cruciate ligament (ACL) reconstruction using the fascia lata has undergone a number of technical modifications since the work of Hey-Groves, MacIntosh, and Jaeger. Arthroscopy has simplified this technique, notably in the positioning of the tunnels. Minimally invasive harvesting through two lateral proximal and distal approaches considerably reduces cosmetic problems. The femoral tunnel is made from the outside to the inside using a specific targeting device, and the transplant harvest site is closed using the Jaeger procedure so as not to weaken lateral knee stabilizing structures. This procedure consists in opening the lateral intermuscular septum 1cm from the femur to let it shift laterally and allow the transplant harvesting area to be closed. This technique uses a fascia lata transplant, the harvesting of which has shown few iatrogenous complications but requires rigorous adherence to certain rules.

High independent prognostic and predictive value of circulating tumor cells compared with serum tumor markers in a large prospective trial in first-line chemotherapy for metastatic breast cancer patients

BACKGROUND

Circulating tumor cells (CTCs) are a prognostic marker in metastatic breast cancer, but comparisons with serum tumor markers (CA 15-3, carcinoembryonic antigen and lactate dehydrogenase) variations are needed.

PATIENTS AND METHODS

CTCs were counted with CellSearch® at baseline, before cycle 2 (C2) and cycle 3 or 4 (C3/4) in 267 metastatic breast cancer patients on first-line chemotherapy with/without targeted therapy.

RESULTS

Baseline CTC detection rate was 65% with ≥1 CTC/7.5 ml threshold and 44% with ≥5 CTC/7.5 ml and was independent of subtypes (luminal, triple negative, human epithelial growth factor receptor 2 (HER2)+). CTCs were associated with tumor markers, bone/liver involvement, tumor burden and performance status. CTC detection ≥1 CTC/7.5 ml was a strong prognostic factor for progression-free survival (PFS), P < 0.0001. Threshold of CTC ≥5 was statistically significant for PFS and overall survival (OS), P = 0.03 on multivariate analysis. Among patients with ≥5 CTC/7.5 ml at baseline, 50% had <5 CTC/7.5 ml at C2. Changes were correlated with both PFS and OS (P < 0.0001). All patients receiving anti-HER2 therapy had <5 CTC/7.5 ml after three cycles of treatment.

CONCLUSION

This is the largest prospective series validating the prognostic value of CTC independently from serum tumor marker. Elevated CTCs before C2 are an early predictive marker of poor PFS and OS, which could be used to monitor treatment benefit. CTC decrease under treatment seems stronger with targeted therapy.

Spatial and temporal distribution of zooplankton related to the environmental conditions in the coral reef lagoon of New Caledonia, Southwest Pacific

The distribution of zooplanktonic prey of fish larvae was examined in three bays and two lagoonal stations in the Southwest lagoon of New Caledonia. Water column conditions were characterized by increasing chlorophyll a and particulate organic matter (POM) concentrations from the lagoon to the estuarine bay. The mean zooplankton settled volume and total density were significantly higher in the estuarine bay, reaching 35.1 mL m(-3) and 3.5 x 10(5) individuals m(-3), respectively. The total zooplankton density also progressively increased along the sampling period. The composition of assemblages differed between the lagoon and the bays, and was similar in the three bays. Wind speed, surface temperature, chlorophyll a and POM explained these variations, as revealed by a co-inertia analysis (COIA). The prey preferred by fish larvae, i.e. small crustaceans and small copepods, were more abundant in bays. Sheltered bays, most influenced by terrigenous inputs, are likely to provide the best feeding conditions.

Do Transcriptomic Markers Provide Significant and Stable Information in Addition to Standard Markers, for the Prediction of Pathological Complete Response in Breast Cancer?

Background: The aim of this study was to investigate and quantify the contribution of transcriptomic markers, in addition to strong predictors such as oestrogen receptor status, to the prediction of pathological complete response (pCR) in locally advanced breast cancer.Patients: The RNA profiles were analyzed using U133 plus 2.0 Affymetrix. We included 189 patients out of 340 patients entered in a neoadjuvant chemotherapy trial for large operable and locally advanced breast cancer. After four cycles of epirubicin–cyclophosphamide, patients were randomly allocated to four cycles of docetaxel with or without celecoxib for patients with HER2-negative tumors, and docetaxel with or without trastuzumab for patients with HER2-positive tumors, respectively. Proportions of pCR in each group were equal to 0.12, 0.16, 0.15 and 0.24 respectively. Patients who received trastuzumab (N=36) were discard from our example, in order to deal with similar proportions of pCR.Methods: The whole sample was divided into a training set (N=81) and a validation set (N=72). Using the training set, two predictive models were built using multivariate logistic regression models. In the first model (M1), usual clinical and biological significant markers were included. In the second model (M2), in addition to the significant parameters of M1, significant transcriptomic variables were included. Diagnostics of both predictive models were assessed on the validation set through sensitivity and specificity estimates. Simulations were performed to investigate stability of model M2.Results: In M1, oestrogen receptor status and tumor size were found to have a strong predictive role in the prediction of pCR. In addition to these classical markers, genes belonging to biological pathways involved in proliferation and microtubule stabilization appeared to have a strong role in the prediction of pCR (model M2). Validation of M1 on the validation set provided 70% of sensitivity and 86% of specificity. Validation of M2 on the validation set yielded to a better sensitivity of 80% and a specificity of 81%. Using simulations, we showed that several different predictive models M2 yielded to similar performances on the validation set. Conclusion: Our study showed that transcriptomic markers provided significant information in addition to usual biological markers for the prediction of pCR. In addition, predictive model with both usual and transcriptomic markers may lead in an improvement of the classification performances. However, as illustrated by simulations, predictive models with both classical and transcriptomic markers are not exclusive. The contribution of transcriptomic data for the prediction of pCR is straightforward, but finding a stable predictive model remains a great challenge.Supported by PHRC AOM/2OO2/02117, Pfizer inc., Roche, sanofi-aventis.ISRCTN10059974

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2035.

[Early failure of anterior bone block in multidirectional shoulder instability: a case report]

We report the case of a 47-year-old female patient who developed predominantly anterior multidirectional glenohumeral instability. After rehabilitation, this patient was treated surgically with an anterior coracoid bone block using the Latarjet technique. The second postoperative day, the control scan revealed posterior glenohumeral dislocation. The patient underwent a second operation for a posterior iliac block. At last clinical follow-up (six years), the patient had normal shoulder motion; shoulder function was considered excellent using the clinical scores. We recall the pathogenic hypotheses explaining multidirectional shoulder instability and discuss the proposed treatments. This case illustrates the difficult diagnosis and therapeutic management of multidirectional instability. Under general anesthesia, examination showed that posterior laxity predominated while paradoxically, the patient presented predominantly anteromedial dislocations. This case is also exceptional by the development of posterior dislocation, an unusual postoperative complication after an anterior bone block; we describe the therapeutic options. In the event of multidirectional instability with bone injuries, we recommend a block in the direction of the instability. Preoperative examination under general anesthesia can be helpful in understanding the mechanism of residual postoperative instability, which would require complementary surgical stabilization.

Altérations architecturales et neuromusculaires du muscle vastus lateralis chez des patients âgés atteints de gonarthrose unilatérale

AIM

The aim of this study was to determine the mechanisms involved in muscle weakness in elderly patients with unilateral knee osteoarthritis.

SUBJECTS

We investigated 7 patients with unilateral knee osteoarthritis.

METHOD

We measured knee position sense and isometric maximal voluntary contraction (MVC) of the knee extensors. Electromyographic (EMG) measurement of biceps femoris (BF), rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) involved different levels of contraction (25, 50, 75 and 100% MVC). Neuromuscular efficiency of quadriceps was also calculated (MVC/EMG). Ultrasonography was used to investigate the VL architectural parameters at the median part of the VL for different levels of contraction (25, 50, and 75% MVC). All tests were performed on the osteoarthritic and healthy knees.

RESULTS

The quadriceps MVC of the affected knee was reduced by 30%. The VL thickness of the affected knee was 10% smaller than that of the unaffected knee. VL activity seen on EMG did not differ between knees, but RF, VM and BF activity was greater in the unaffected than affected knee. Neuromuscular efficiency was higher (26%) in the unaffected knee. Knee position sense was reduced by 33% in the affected knee.

CONCLUSION

Quadriceps weakness associated with knee osteoarthritis seems to be related to changes in muscle rather than pennation angle and changes in fascicule length.

Use of the SCOT solution in kidney transplantation: preliminary report

SUBJECT

This article reports preliminary findings relating to the use of a new preservation solution, the Solution de Conservation des Organes et des Tissus (SCOT), in renal transplantation. This fourth-generation solution combines an extracellular-like composition with 20 kDa polyethylene-glycol, known for its cell-protection capacity and immunocamouflage properties.

METHODS

We have reported preliminary data obtained in 29 transplantations (25 cadaveric donors and 4 living related donors) between December 2004 and November 2005. The SCOT solution was used for both in situ flush and static preservation. We compared primary organ nonfunction and delayed graft function rates as well as blood creatinine levels in recipients of grafts processed with SCOT solution, versus University of Wisconsin solution (paired for age with the previous group) and with EuroCollins solution (historic data).

RESULTS

We observed delayed graft-function in 10% of the SCOT-processed group, 14% in the University of Wisconsin solution group, and 23% of the EuroCollins group. No case of primary organ nonfunction was reported. Creatinine levels in both SCOT and University of Wisconsin solution groups were similar. We did not observe any humoral or cellular graft rejection in the first 3 months after transplantation. In light of these preliminary results, the use of SCOT is safe for kidney preservation in the human setting. Further experience is warranted to assess the clinical consequences of its immunocamouflage properties as described in animal models.

[Sequelae of intra-articular calcaneal fractures: patterns and management]

PURPOSE OF THE STUDY

We reviewed retrospectively 24 feet with sequelae of transtalar process fractures of the calcaneum in order to identify the lesion pattern and determine optimal management options, both for acute and sequelar lesions.

MATERIAL AND METHODS

There were fourteen men and nine women, mean age 42 years (19-73). Twenty-three had subtalar osteoarthritis, eight had calcaneocuboid osteoarthritis, and fifteen had lateral submalleolar conflicts. There were twelve fibular tendon dislocations or fissurations, three tarsal tunnel syndromes, and two plantar splinters. Prior to treatment, all patients complained of pain. Preoperatively, walking distance was less than 500 m for thirteen patients, 2000-3000 m for four, and greater than 3000 m for five. Mean subtalar joint motion was 30% (0-100%) compared with the healthy side and mean frontal misalignment of the rear foot was 6 degrees valgus. Physical examination, podoscopy and x-rays were obtained in all patients. The Kitaoka score was noted.

RESULT

Mean follow-up was 36 months (24-72). Sequelae were treated with a single procedure or with combinations: subtalar arthrodesis (n = 23) including one in association with calcaneocuboid arthrodesis, tension on fibular tendons (n = 7), neurolysis of the posterior tibial nerve (n = 3), resection of plantar splinters (n = 2), resection of the lateral shell (n = 14), and osteotomy (n = 2) to lower the greater tubercle of the calcaneum because of pain when wearing shoes. The mean Kitaoka function score was 31.7/100 (14-79) preoperatively. After treatment, the mean score was 81.7/100 (31-94), giving a 73.2% gain. The outcome was considered good in sixteen feet, fair in six, and poor in two. Mean walking distance was greater than 3000 m for 18 patients. Mean frontal misalignment of the rear foot under loading was 4.5 degrees valgus and the podoscopy demonstrated flat foot in thirteen patients. Three subtalar arthrodesis required revision for nonhealing.

DISCUSSION

Initial treatment of a fracture, particularly an articular fracture, of the calcaneum must avoid disabling postoperative pain and shoe wearing problems. These sequelae basically concern: subtalar and calcaneocuboid arthritis, lateral submalleolar conflict, fibular tendon injury, plantar splinters, tarsal tunnel syndrome, loss of height, and misalignment of the rear foot. At the sequelar stage, the physical examination is primordial to confirm the lesion and search for any complication which could develop later postoperatively when walking distance becomes longer. For nine patients with residual pain, four resulted from lesions which were missed at the preoperative physical examination. Arthrodesis of the subtalar joint should be preferred over realignment of the rear foot and can be associated with the treatment of conflicts. This management scheme allows treating during a single operative time all sequelae, thus limiting recovery time. A scan of the ankle and foot with or without opacification of the fibular tendons is needed to confirm the physical examination which, for us, remains the key to successful surgery.

Long-term host unresponsiveness to encapsulated xenogeneic myoblasts after transient immunosuppression

BACKGROUND

Encapsulating cells prevents the immune destruction of allogeneic cells in the subcutaneous site as well as allogeneic and xenogeneic cells in the central nervous system. However, when encapsulated xenogeneic cells are implanted s.c., they may be subject to rejection by the host.

METHODS

Murine C2C12 myoblasts engineered to secrete mouse erythropoietin (mEpo) were used to evaluate the response of control versus FK506-treated xenogeneic recipients (Fischer rats) to encapsulated myoblasts implanted in the s.c. site.

RESULTS

Encapsulated C2C12 mEpo cells were rapidly eliminated in immunocompetent Fischer rats. Devices transplanted into nude rats induced a sustained increase in the hematocrit, associated with an extended viability of the encapsulated cells. Short-term immunosuppression with FK506, for periods lasting either 1, 2, or 4 weeks after implantation, permitted the long-term survival of encapsulated C2C12 mEpo cells in Fischer rats. Animals increased their hematocrits to more than 70% and maintained these levels for 13 weeks, independent of the duration of FK506 treatment. Unencapsulated C2C12 mEpo cells injected i.m. in immunosuppressed animals were rejected over this same period.

CONCLUSIONS

Encapsulation alone cannot protect xenogeneic myoblasts from immune destruction in the s.c. site. These results highlight the importance of combining the technique of cell encapsulation with transient immunosuppression to achieve long-term survival of xenografted myoblasts in a peripheral immunoreactive site.

Encapsulated, genetically engineered cells, secreting glucagon-like peptide-1 for the treatment of non-insulin-dependent diabetes mellitus

Non-insulin-dependent, or type II, diabetes mellitus is characterized by a progressive impairment of glucose-induced insulin secretion by pancreatic beta cells and by a relative decreased sensitivity of target tissues to the action of this hormone. About one third of type II diabetic patients are treated with oral hypoglycemic agents to stimulate insulin secretion. These drugs however risk inducing hypoglycemia and, over time, lose their efficacy. An alternative treatment is the use of glucagon-like peptide-1 (GLP-1), a gut peptidic hormone with a strong insulinotropic activity. Its activity depends of the presence of normal blood glucose concentrations and therefore does not risk inducing hypoglycemia. GLP-1 can correct hyperglycemia in diabetic patients, even in those no longer responding to hypoglycemic agents. Because it is a peptide, GLP-1 must be administered by injection; this may prevent its wide therapeutic use. Here we propose to use cell lines genetically engineered to secrete a mutant form of GLP-1 which has a longer half-life in vivo but which is as potent as the wild-type peptide. The genetically engineered cells are then encapsulated in semi-permeable hollow fibers for implantation in diabetic hosts for constant, long-term, in situ delivery of the peptide. This approach may be a novel therapy for type II diabetes.

Lentivirus-mediated Bcl-2 expression in betaTC-tet cells improves resistance to hypoxia and cytokine-induced apoptosis while preserving in vitro and in vivo control of insulin secretion

betaTC-tet cells are conditionally immortalized pancreatic beta cells which can confer long-term correction of hyperglycemia when transplanted in syngeneic streptozocin diabetic mice. The use of these cells for control of type I diabetes in humans will require their encapsulation and transplantation in non-native sites where relative hypoxia and cytokines may threaten their survival. In this study we genetically engineered betaTC-tet cells with the anti-apoptotic gene Bcl-2 using new lentiviral vectors and showed that it protected this cell line against apoptosis induced by hypoxia, staurosporine and a mixture of cytokines (IL-1beta, IFN-gamma and TNF-alpha). We further demonstrated that Bcl-2 expression permitted growth at higher cell density and with shorter doubling time. Expression of Bcl-2, however, did not inter- fere either with the intrinsic mechanism of growth arrest present in the betaTC-tet cells or with their normal glucose dose-dependent insulin secretory activity. Furthermore, Bcl-2 expressing betaTC-tet cells retained their capacity to secrete insulin under mild hypoxia. Finally, transplantation of these cells under the kidney capsule of streptozocin diabetic C3H mice corrected hyperglycemia for several months. These results demonstrate that the murine betaTC-tet cell line can be genetically modified to improve its resistance against different stress-induced apoptosis while preserving its normal physiological function. These modified cells represent an improved source for cell transplantation therapy of type I diabetes.

Severe hyperflexion sprains of the lower cervical spine in adults

Severe sprains of the cervical spine result from a traumatic rupture of the intervertebral disc and ligaments. Although rare, these lesions may lead to a significant kyphotic deformity if they are not surgically treated. The treatment of such a kyphotic deformity may consist of surgical fixation of the lesion through either an anterior or posterior approach. A retrospective study has been done examining 44 severe cervical sprains in 41 patients surgically treated through a posterior approach, using Roy-Camille plates. With an average followup of 29 months (range, 6-60 months), 73% of the patients recovered a normal range of spinal motion, with either moderate or no pain. No neurologic or vascular complications directly attributable to posterior plating and no secondary kyphosis were observed. A moderate sagittal displacement with kyphotic angulation occurred above the fusion in five patients. Posterior screw plate fixation appears to be a safe and effective treatment for severe hyperflexion sprain of the lower cervical spine in the adult.

Control of erythropoietin secretion by doxycycline or mifepristone in mice bearing polymer-encapsulated engineered cells

Cell encapsulation offers a safe and manufacturable method for the systemic delivery of therapeutic proteins from genetically engineered cells. However, control of dose delivery remains a major issue with regard to clinical application. We generated populations of immortalized murine NIH 3T3 fibroblasts that secrete mouse erythropoietin (Epo) in response to stimulation by doxycycline or mifepristone. Engineered cells were introduced into AN69 hollow fibers, which were implanted in the peritoneal cavity or recipient mice. Animals receiving doxycycline or mifepristone showed stable polyhemia and increased serum Epo concentrations over a 6-month observation period, whereas animals not receiving the inducer drug had normal hematocrits. Epo secretion could be switched on and off, depending on the presence of doxycycline in the drinking water. In contrast, polyhemia was hardly reversible after subcutaneous injections of mifepristone. These data show that a permanent and regulated systemic delivery of a therapeutic protein can be obtained by the in vivo implantation of engineered allogeneic cells immunoprotected in membrane polymers.

[Evaluation of the direct cost of trochanteric fractures in the elderly]

PURPOSE OF THE STUDY

The cost effectiveness of trochanteric hip fractures in 1995 at Pitié-Salpétrière Hospital in Paris has been thoroughly analysed. The aim of this retrospective study was to identify the factors responsible for the variation in the treatment cost of those fractures.

MATERIAL AND METHODS

Cost, Hospital stay, functional status, ASA score, mental status and surgical treatment were analysed in 74 patients aged over 60 years old.

RESULTS

The mean cost per patient was 23,901 FF divided as follows: 8.5 per cent for preoperative care, 40.5 per cent for surgical procedures, 51 per cent for post-operative care. The mean hospital stay was 18 days. The cost of hospital personnel (44 per cent) and medical materiel (26 per cent) were the two main sources of hospital expenses beside medical investigations (11 per cent), hostelry (8 per cent), blood transfusion (6 per cent) and drugs (5 per cent).

DISCUSSION

The duration of hospital stay was the only factor that affected statistically the mean cost per patient. Furthermore, factors related to the patient as age, sex, place of residence prior to admission, functional status, ASA score, mental status, had no influence on cost variation.

CONCLUSION

Therefore, the best way to reduce the cost of trochanteric fractures treatment is to develop convalescence structures to avoid a lengthy and costly hospital stay and to minimize the abuse utilization of medical materials.

[Dislocation of the femoral component of an unicondylar knee prosthesis. Apropos of a case]

INTRODUCTION

Femoral component dislocation in unicondylar knee arthroplasty is rare. One case is reported.

MATERIAL AND METHODS

A 59 years old man required revision of his unicondylar knee arthroplasty for loosening and dislocation of the femoral component 3 years after its insertion. Revision was performed and we found a technical error: distal and posterior femoral cut was too thin, and with components in place, there was a tendancy for the components to "rock" as the knee was flexed. The implants were too tight in flexion. A new unicondylar knee arthroplasty was performed.

DISCUSSION

The posterior condylar bone resection should reach at least the thickness of the metal implant. It is better to resect slightly too much of the posterior condyle than too little in order to avoid tightening of the knee in flexion. The femoral component must accurately reproduces the anterior-posterior dimension of the femoral condyle.

CONCLUSION

With better selection of patients and surgeons who are more familiar to this type of procedure loosening and dislocation of an unicondylar knee arthroplasty should be avoided.

Application of AN69 hydrogel to islet encapsulation. Evaluation in streptozotocin-induced diabetic rat model

The polymer AN69 (polyacrylonitrile-sodium methallylsulfonate) is a reference in biocompatibility in the field of hemodialysis. Its use for the encapsulation of living cells has been already described, but this study is the first description of AN69 hydrogel-encapsulated islet isograft in streptozotocin (STZ) diabetic rats. The aim of this work is to evaluate the biocompatibility of the AN69 hydrogel by comparison of the efficacy of free versus encapsulated islets transplanted to balance diabetes. Pancreatic islets are isolated from adult male Lewis rats by a standard collagenase digestion and purified on Ficoll density gradients. The AN69 hollow fiber is obtained by coextrusion of an 8% AN69 collodion. The hollow fiber is filled with islets suspended in agarose at the final concentration of 10,000 islets/ml, closed with surgical clips and implanted. The recipients are rendered diabetic by intravenous injection of STZ. The experimental design includes 4 groups of 8 rats: group 1: control, group 2: diabetic rats intraperitoneally implanted with 6000 free islets, group 3: diabetic rats intraperitoneally implanted with 9000 encapsulated islets, group 4: diabetic control. Weight and fasting glycemia are evaluated twice a week, diuresis once a week. After free islet implantation, rat survival is improved with glycemia below 250 mg/dl during 22 days. Compared to group 2, the status of group 3 is better, with a glycemia below 250 mg/dl during at least 70 days. This tends to demonstrate the biocompatibility of AN69 and is the first step of the validation of the use of AN69 for living cell encapsulation.

Standardization of procedure for efficient ex vivo gene transfer into porcine pancreatic islets with cationic liposomes

BACKGROUND

New strategies to improve the outcome of encapsulated porcine islet transplantation may involve the transfer of gene sequences affecting islet viability. While adenoviral vectors appear as the most efficient gene transfer system so far established for islets, non-viral-based vectors are most likely to fulfill microbiological safety criteria and be retained in the clinical setting. Our aim was to standardize the procedures of gene transfer into adult porcine islets using cationic liposome DOTAP.

METHODS

Porcine islets obtained by collagenase digestion and density gradient purification were lipofected with plasmids coding for luciferase or beta-galactosidase under the control of simian virus 40 or cytomegalovirus promoter. The following parameters were explored: exposure time to vector (1-48 hr), DNA amount (1-15 microg/500 islets), and DOTAP to DNA ratio (2-16). Reporter gene expression was determined 48-72 hr after lipofection.

RESULTS

Efficiency and reproducibility of transfection were maximal with the following procedure: 3-hr exposure time followed by islet washing, 12 microg of DNA per 500 islets (150 microm equivalent), and DOTAP to DNA ratio of 12 microl/microg. Freshly isolated islets in large aliquots (n=4000 in 50-ml tubes) were efficiently transduced with this procedure, and distribution of gene expression was homogenous when islets were subsequently plated in 500-islet aliquots. Luciferase gene expression was detected for a minimum of 7 days after lipofection. Gene expression was also evident up to 4 weeks after islet transplantation beneath the kidney capsule of athymic mice. Transfection of islets using the beta-galactosidase vector yielded 25% positive islets. Islet viability was not adversely affected.

CONCLUSIONS

This islet lipofection procedure may help achieve the local release of a bioactive peptide in the graft environment and have therapeutic applications in islet transplantation.

[Lamino-arthrectomy technique for lumbar spine stenosis]

Surgical treatment should to be proposed in lumbar spinal stenosis, when well conducted conservative treatment is insufficient (severe pain and/or neurologic involvement). The goal of the treatment is to enlarge the canal: decompression of the dura mater in case of central stenosis and, radicular decompression in case of lateral stenosis. Two opposing techniques can be used: the lamino-arthrectomy and the recalibration. We describe the lamino-arthrectomy techniques, results and complications about 202 operated cases. The classic laminectomy is a posterior resection, with a partial arthrectomy (to release the symptomatic root involved by degenerative arthritic changes in zygapophyseal joints) and a systematic exploration of the posterior vertebral body. In the "lobster shell" technique, the laminectomy is conducted on several levels with a jigsaw. The others gestures are identical to the classic laminectomy.The complications were of three types; during surgery (35 dura mater gaps, 10 radicular injuries), early post-operative (2 non compressive haematomas reoperated in two cases, 6 infections, 4 roots involvement and 4 paraplegias) and the latest complications (11 destabilisations, 4 recurrences). The results were good in 86,2% of the series (most of oldest patients) and, 71,4% of the patients regained normal locomotion. The posterolateral arthrodesis is discussed, with osteosynthesis by plates and pedicle screws technique described by R. Roy-Camille. The results prove the surgical efficiency of extensive lamino-arthrectomy in symptomatic narrow lumbar canal. The efficiency on lumbago and neurologic deficit is less.

[Destabilization after surgical treatment of narrow lumbar canal: when should arthrodesis be performed?]

Post-operative spine displacement occurs by excessive or aggravated vertebral sliding. Sex and age, anatomics factors (pre-operative displacement, intersomatic discs quality, hyperlordosis) and operative factors (extensive laminectomy, artherectomy) are predisposing factors. The risk of post-operative vertebral displacement is calculated by a fine pre and per-operative analysis of these pre-disposing factors: Tolerance to post-operative spinal displacement cannot be foreseen and surgical recovery may be difficult whenever.

Decreased mesenteric blood flow supplying retrosternal esophageal ileocoloplastic grafts during positive-pressure breathing

Esophageal replacement after esophagogastric injury caused by ingestion of lye may require the interposition of a retrosternal ileocolic graft. In this new anatomic situation, the mesenteric circulation supplying the graft is subjected to the intrathoracic pressure surrounding the graft. Thus, mesenteric blood flow supplying the graft may be impaired when intrathoracic pressure is increased during mechanical ventilation. This study was designed to evaluate the effect of increasing intrathoracic pressure by application of a positive end-expiratory pressure on mesenteric blood flow supplying esophageal ileocolic grafts. Eight cases were studied in the immediate postoperative period. Miniaturized implantable Doppler microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Two sets of measurements were successively performed with zero end-expiratory pressure ventilation and after application of a 15 cm water positive end-expiratory pressure. Positive end-expiratory pressure induces mean arterial pressure (-12%); p < 0.05) and cardiac output (-17%; p < 0.05) decrease. Mesenteric blood flow also decreases (-38%; p < 0.05) as did the mesenteric blood flow/cardiac output ratio, suggesting a potential mesenteric vasoconstriction assessed by mesenteric vascular resistance increase and mesenteric diastolic blood flow velocity decrease. These results suggest that, in the particular anatomic situation of the graft, increased intrathoracic pressure induces mesenteric blood flow decrease in relation to systemic hemodynamic alterations associated with perivisceral pressure increase. This change may be deleterious to graft perfusion.

MRI evaluation of sacral cysts

Sacral cysts or intrasacral sacral meningeal cysts constitute a well-defined entity. Their clinical presentation is protean. Few cases have been reported concerning their MR aspects. From a series of six patients, the authors present the MR images. MRI is the examination of choice to demonstrate their liquid content. MRI provides a good evaluation of the lesion, and sagittal images show the intrasacral development. MRI scan appears to be superior to CT scan.

Usefulness of perioperative pulsed Doppler flowmetry in predicting postoperative local ischemic complications after ileocolic esophagoplasty

Regional ischemia may induce cervical anastomosis leakage or stenosis or graft necrosis after esophageal reconstruction by retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the relationship between immediate postoperative arterial blood supply to the graft, arterial patency monitored by angiography, and clinical outcome. Eight patients (mean age 30 +/- 4 years; standard deviation) were studied. Miniaturized Doppler implantable microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Systemic hemodynamic parameters and mesenteric hemodynamic data were collected 3 hours after the end of the surgical procedure. These data were compared with the angiogram of the right superior colic artery supplying the graft, systematically performed on the fifteenth postoperative day, and with the clinical course of follow-up for 3 months. Five patients (group 1) had excellent clinical and angiographic results. Mean mesenteric blood flow in these patients was 51 +/- 49 ml.min-1 (+/- standard deviation, ranging from 9 to 122). Three patients (group 2) had a poor clinical outcome. One had early complete graft necrosis and the two others had leakage of the cervical anastomosis with poor distal arterial vascularization of the graft on the angiogram. Mean mesenteric blood flow was nul in the first patient and, respectively, 24 and 28 ml.min-1 in the two others. Cardiac output and mean arterial pressure were in the same range for all patients. Phasic velocity shape analysis revealed that the three group 2 patients had an end-systolic or end-diastolic reverse flow pattern that was not observed in the five group 1 patients, which suggested a submaximal increase in downstream vascular resistance. This reverse flow pattern seems to be a good predictor of ischemia-related complications. We conclude that perioperative pulsed Doppler blood flow monitoring in an ileocolic graft may be useful for the diagnosis and prevention of ischemic complications.

[Pancreatic fistula following cephalic duodenopancreatectomy. Directed fistulization or total pancreatic exeresis?]

A frequent complication (8.5 to 52.8%) of pancreatoduodenectomy (PD) for cancer, pancreatic fistula (PF) is difficult to treat, and an analysis of 30 cases of PD (27 for cancer, 3 for chronic pancreatitis) is used to determine risk factors and most effective therapy. Fistula developed in 6 cases (20%) and three risk factors were determined: preoperative renal impairment and hypoalbuminemia and ligature of pancreatic stump. Although not statistically significant, other factors--cancer, emergency surgery, fragile pancreatic tissue, thin Wirsung, pancreatojejunal anastomosis, absence of decompression of the raised jejunal loop--in this small series nevertheless provoked a marked increase in PF. One patient recovered after medical treatment, all five patients operated upon by whatever technique failing to survive. This agrees with literature data indicating heavy mortality (44.4 to 100%) after surgery. This should therefore be reserved for cases of PF failing to respond to adequate medical treatment, or with hemorrhage or intra-abdominal sepsis not controlled medically. The most effective therapy for PF is prophylactic, combining selection of patients as a function of risk factors, and treatment of pancreatic stump adapted to caliber of Wirsung and quality of remaining pancreatic tissue.