Cortical Grafts Research Articles

Effects of Long-Term Grafting on Follicular Growth in Porcine Ovarian Cortical Grafts Xenoplanted to Severe Combined Immunodeficient (SCID) Mice

To establish a tool for the study of follicular growth and development, we xenotransplanted small pieces (approximately 1 mm3) of porcine ovarian cortical tissues containing only primordial follicles and small preantral follicles under the capsules of kidneys of severe combined immunodeficient (SCID) mice (8-10 weeks old). The changes in cell proliferation and cell death/apoptosis, and vascularization in xenotransplanted follicles during follicular growth and development were analyzed histochemically at 1-26 weeks after operation. Follicles in grafted ovarian tissues grew rapidly forming an antral cavity (a hallmark of tertiary follicles) at 1 week after grafting. The diameter of the follicles in transplanted tissues ranged from 0.5 to 1.5 mm, from 0.5 to 2.0 mm and from 0.5 to 3.0 mm at 1, 2 and 26 weeks after the operation, respectively. Histological observation of ovarian tissues at 26 weeks after grafting revealed that all grafts had abundant capillary vessels, which invaded from murine organs and surrounded the growing follicles. Grafted small preantral follicles developed to the antral stages at 1 week after grafting and growing antral follicles survived at 26 weeks after grafting. The oocytes in the growing follicles were easily recovered for evaluating the quality. Our simple xenografting system is easy to use and a good experimental tool for the study of folliclular growth and development in porcine ovaries.

Using resorbable screws for fixation of cortical onlay bone grafts: An in vivo study in rabbits

The purpose of this study is to test bioresorbable screws as an alternative to titanium screw graft fixation. When cortical onlay grafts are used, it is necessary to rigidly immobilize them with titanium screws into the recipient site. The screws must be removed before placing implants into this site. Bioresorbable screws may be an alternative to titanium fixation, eliminating the additional morbidity associated with this. Fifteen New Zealand White rabbits were divided into 3 groups. Bilateral tibial onlay bone grafts were placed in the mandible and secured using titanium fixation, bioresorbable fixation, or no fixation. After 6 weeks, all grafted sites were harvested. Hematoxylin-eosin and Giemsa staining were performed to evaluate inflammation, graft integration, and thickness. The treatment groups showed evidence of consolidation under light microscopy. Smooth integration of the graft borders with the recipient bone was identified. No integration was seen in the control group. The average thickness of the grafted sites was: 1) bioresorbable, 2.28 mm; 2) titanium, 1.87 mm; and 3) control, 1.06 mm. The differences were statistically significant (P = .0004) between the titanium group and the control group, as well as between the bioresorbable and the control group (P = .01). There was no statistically significant difference between the 2 treatment groups (P = .19). The overall thickness of the treatment specimens was greater than that of the control group. The bioresorbable group showed graft integration equal to that of the titanium group, making it an adequate alternative for graft fixation.

Referral patterns in implant dentistry

omy to more predictably correct these defects. Five consecutive cases of maxillary alveolar distraction (AD) were compared to 5 consecutive osteotomy cases (SO). Parameters studied were the total distraction length desired and achieved, reconstitution of tissue height, favorable vector control, need for additional bone grafting, need for soft tissue grafting, total treatment time. Results: The sandwich alveolar bone graft technique was developed and applied in 5 sites, 5 patients. The surgical technique involves an alveolar osteotomy, for vertical displacement of the inferior fragment and placement of an interpositional autologous mandibular graft. A primary cortical mandibular ramus graft served as the donor site. Key surgical features included elevation of bone to the bone level of adjacent teeth, mobilization of the alveolar segment and retention of the adhering overlying gingival. Mobilization of the distal segment and malleting the graft into place were important for stability. From 5 to 8 mm of desired bony height for SO and 10 to 14 mm for AD were measured using periapical radiographs. Prolonged total treatment time, greater distraction lengths, reduced maintenance of tissue height, and increased need for additional bone grafting as a labial onlay were noted for AD, for equivalent intervals of 6-8 months later. The loss of tissue height could be accommodated for by modification of incision design for implant placement. The disparate distracted lengths may have accounted for the need for additional bone grafting and unfavorable vector control for AD. The recuperation following SO was similar requiring a 2to 5-day postoperative disability period, but there were fewer postoperative visits. AD required a procedure to eliminate the distraction device. Dehiscence over the distraction device could lead to unfavorable esthetic scarring. In contrast, to AD, there was no incidence of dehiscence or delayed labial grafting with SO Conclusion: Advantages of the technique noted include: accurate reliable reconstruction of the alveolus, elimination of additional bony reconstructive procedures, no relapse in the short term, and safer use of an acrylic interim denture for esthetic purposes. On the basis of this pilot study it appears that for vertical lengths of 5-8 mm, SO seems a more predictable procedure simply based on the number of postoperative visits and reduced total treatment time.

A decision tree for bone graft success

Successful bone grafts to the maxillomandibular complex depend upon an understanding of basic bone biology, appropriate surgical technique, evaluation of recipient and donor sites, and knowledge of bone graft materials.This lecture presents the protocol for bone graft success and discusses the reasons that affect success and/or failure. Particular attention is directed to evaluation of the recipient site and specifically the quality and quantity of cancellous and cortical bone. This evaluation combined with an understanding of basic surgical principles aids the clinician to decide not only on appropriate surgical procedure, but upon the use of autogenous bone versus allogeneic or alloplastic grafts. This lecture guides the clinician to answer specific questions of when to use an onlay bone graft, a split cortical graft, the sandwich graft, the sinus graft, ridge preservation, socket grafts, particulate grafts with titanium or membrane stabilization.Autogenous bone has been considered the “gold standard” as the most predictable graft. However, harvesting autogenous bone requires a second surgical site, increased surgical and healing time, and increase morbidity. Is there an alternative to autogenous grafts? This lecture also discusses when autogenous grafts are absolutely indicated and when alternative graft materials are successful as well as when they fail to produce predictable success.ReferencesRoberts E, et al: Bone physiology and metabolism. Calif Dent Assoc J October:54, 1987Reddi AM, Wientroub S, Muthukumaran N: Biological principle of bone induction. Orthop Clin North Am 18:207, 1987Wittbjer J, Palmer B: Osteogenetic activity in composite grafts of demineralized compact bone and marrow. Clin Orthop 173:229, 1983 Successful bone grafts to the maxillomandibular complex depend upon an understanding of basic bone biology, appropriate surgical technique, evaluation of recipient and donor sites, and knowledge of bone graft materials. This lecture presents the protocol for bone graft success and discusses the reasons that affect success and/or failure. Particular attention is directed to evaluation of the recipient site and specifically the quality and quantity of cancellous and cortical bone. This evaluation combined with an understanding of basic surgical principles aids the clinician to decide not only on appropriate surgical procedure, but upon the use of autogenous bone versus allogeneic or alloplastic grafts. This lecture guides the clinician to answer specific questions of when to use an onlay bone graft, a split cortical graft, the sandwich graft, the sinus graft, ridge preservation, socket grafts, particulate grafts with titanium or membrane stabilization. Autogenous bone has been considered the “gold standard” as the most predictable graft. However, harvesting autogenous bone requires a second surgical site, increased surgical and healing time, and increase morbidity. Is there an alternative to autogenous grafts? This lecture also discusses when autogenous grafts are absolutely indicated and when alternative graft materials are successful as well as when they fail to produce predictable success. References Roberts E, et al: Bone physiology and metabolism. Calif Dent Assoc J October:54, 1987 Reddi AM, Wientroub S, Muthukumaran N: Biological principle of bone induction. Orthop Clin North Am 18:207, 1987 Wittbjer J, Palmer B: Osteogenetic activity in composite grafts of demineralized compact bone and marrow. Clin Orthop 173:229, 1983

Autogenous Bone Grafting for Fractures of the Hand

Autogenous bone grafting of hand fractures often occurs within the milieu of a complex wound. Risks of infection and/or stiffness increase with injury severity, contamination, and the time interval between injury and successful wound closure or coverage. A clean wound is paramount for successful tissue repair, reconstruction, and closure. Skeletal restoration is an integral component of composite wound management. Fracture stabilization enhances pain control, protects soft tissue repairs and reconstruction, inhibits infection, and facilitates bone graft consolidation and functional recovery. Mini plate fixation provides the sustained stability necessary for hand fractures with bone loss to heal. Bone grafting is an essential element of skeletal restitution for defects due to comminution or actual loss. Cancellous bone grafts heal more rapidly and are more resistant to infection than cortical bone grafts and may be preferable for partial or smaller intercalary defects. Cortical or corticocancellous grafts augment stability and may be especially useful for larger segmental diaphyseal defects and articular bone loss requiring arthrodesis.

Anterior cervical fusion using dense cancellous allografts and dynamic plating.

Dense cancellous grafts provide an open matrix for vascular and cellular penetration for early osseous integration. Thus, they provide a better biological fusion substrate than cortical or corticocancellous grafts. The aim of this study is to evaluate the efficacy of the dense cancellous allografts as a substrate for anterior cervical fusion along with instrumentation. This is a retrospective study of 98 patients who underwent anterior cervical discectomy, fusion with dense cancellous allograft bone, and instrumentation using dynamic plating between January 2001 and March 2002. Of these procedures, 60 involved single-level and 38 involved two-level fusions. Subsidence was assessed by plain x-rays at 1, 3, 6, and 12 months and fusion at 3, 6, and 12 months after surgery. Fusion was defined as the appearance of bridging trabecular bone and absence of motion in flexion-extension films. The mean follow-up period was 15 months (range, 12-25 mo). Successful fusion was observed in 70, 84, and 96% of the patients at 3, 6, and 12 months, respectively. The average subsidences for single-level and two-level fusions were 2.0 and 3.2 mm, respectively. No allograft- or hardware-related complications were encountered in our series. Dense cancellous allografts are very effective as bone graft substitutes for achieving anterior cervical fusion along with instrumentation. Successful fusion was observed in 70% of our patients at 3 months, with a fusion rate of 96% at 1 year. These allografts provide an effective replacement for autologous grafts in cervical interbody fusion.

Proximal Femoral Replacements With Megaprostheses

The exact role of proximal femoral replacement (megaprosthesis) in revision hip surgery is unclear. During the past decade remarkable advances in the field of revision hip reconstruction have been made including the availability of allograft cancellous and cortical bone. With the increased use of cortical strut grafts to augment host bone, the indications for the use of megaprostheses have narrowed. Currently, we reserve the use of megaprostheses for elderly or sedentary patients with massive proximal femoral bone loss that cannot be reconstructed by other reconstructive procedures. This may include failed total hip arthroplasty (THA), nonunion of the proximal femur with multiple failed attempts at osteosynthesis, and hip salvage after a failed resection arthroplasty.

Résultats des reprises pour descellement glénoïdien: À propos d’une série multicentrique de 37 prothèses d’épaule

Purpose of the study The purpose of this study was to assess outcome after revision total shoulder arthoplasty as a function of therapeutic options. Material and methods Revision total shoulder arthroplasty procedures were performed in three French centers specialized in shoulder surgery. Mean follow-up was 28.5 months (range 12-69). Constant's score was determined preoperatively and at last follow-up. Nineteen reimplantations of a cemented glenoid, twelve “glenoplasties” without reimplantation and five inverted prosthesis implantations were performed. Arthroplastic resection was performed in one patient with infection. Results The function score improved in all patients. Reimplantation of a cemented glenoid led to significant improvement in function at last follow-up. For patients without reimplantation, bone graft reconstruction of the bone loss led to better results than simple removal of the loosened implant. For patients with cuff tears, use of an inverted prosthesis led to improved clinical scores, particularly for pain. Two patients experienced repeated loosening of cemented glenoids and one patient developed infection requiring a second revision. Discussion Different therapeutic options can be proposed for patients with glenoid loosening. Simply removing the implant is effective in relieving pain but has a modest effect on motion. This type of procedure should be reserved for frail patients requiring an intervention with limited goals. The remaining amount of glenoid bone stock is the key to functional outcome after surgical repair. Glenoid reimplantation can be attempted if only a moderate amount of bone has been lost. Unlike cortical grafts, pure cancellous grafts do not allow reliable reconstruction. After grafting, reimplantation of the glenoid implant can be achieved in a two-stage procedure. Screwed glenoid implants allow fixing the graft in a single operation in better conditions than cemented implants. Inverted prostheses offer a therapeutic solution worth developing for patients with rotator cuff tears and glenoid loosening.

Structural Allograft for Femoral Deficiency in Revision Total Hip Arthroplasty

Purpose: We investigated the results and the effectiveness of structural allografts, which were obtained from a donated cadaver for femoral deficiency in revision total hip arthroplasty. Materials and Methods: We reviewed 27 patients who received a structural allograft for femoral deficiency in revision total hip arthroplasty with a minimum follow-up of 2 years. All allografts were fresh frozen bone obtained from donated cadavers. Whole proximal femur was used in 3 patients and strut or cortical onlay graft in the others. The results were evaluated by using Harris hip scores and by the presence of complications, clinically and stability of stem, osteolysis, radiolucent line, and by the radiographic union of the allograft. Results: The average Harris hip score improved from 40.1 preoperatively to 86.9 postoperatively, and the stem showed bony stability in 18 patients, fibrous stability in 8 patients, and instability in 1 patient due to the recurrence of infection. Radiologically, osteolysis was observed in 4 patients (14.8%), radiolucent line over 2 mm in 1 patient, and union of allografts in 25 patients (92.6%) that showed stable stem. The average union time was 7.5 months. Nonunion of allografts were observed in 2 patients revised with a cancellous bone autograft. Complications were infection in 1 patient, dislocation in 2 patients, and heterotopic ossi fication in 1 patient. Conclusion: Structural allografts obtained from cadaveric donor were used for large femoral deficiency in revision total hip arthroplasty. Our results show that satisfactory union and can successfully restore the bone stock for further surgery.

Giant Cell Tumor Of First Metacarpal

Giant Cell Tumor (GCT) or Osteoclastoma is a benign locally aggressive tumor with a tendency for local recurrence. 85-90% of cases occur in the long bones. Only 2% of cases occur in the hand, and hereto metacarpal involvement is a very rare occurrence with only a few cases reported in the literature so far. We report a case of GCT of 1st metacarpal in a 22-year-old female. We discuss the clinical features, pathological and radiological hallmarks, and the various treatment modalities of such a lesion with emphasis on the reconstructive possibilities using cortical strut grafts.

Improved neural progenitor cell survival when cografted with chromaffin cells in the rat striatum

Transplantation of stem and neural progenitor cells hold great promise in the repair of neuronal tissue lost due to injury or disease. However, survival following transplantation to the adult CNS has been poor, likely due to a lack of neurotrophic factors, such as basic fibroblast growth factor (FGF-2), that are used to maintain and expand these cells in culture. Chromaffin cells produce several neurotrophic agents, including FGF-2, which may aid in both neuroprotection following injury and progenitor cell proliferation and survival. In addition, increased CNS catecholamines have been shown to improve functional recovery following insult. Thus, cotransplants of neural progenitor cells and chromaffin cells may be a useful clinical strategy. To address this, the survival of rat cortical progenitors transplanted to the adult rat striatum with and without bovine chromaffin cell cografts was assessed. Progenitors obtained from E14 embryos were prelabeled with bromodeoxyuridine (BrdU) before transplantation to enable later identification. Transplants were made both unilaterally and bilaterally, where animals received a monograft (progenitor cells alone) on one side and a cograft (progenitors + chromaffin cells) on the other. Histological results after 7, 17, and 30 days posttransplant revealed greatly improved survival of BrdU-labeled cells in the cografts and also less infiltration of presumptive immune cells. In addition, perivascular cuffing was seen in the monografts. In vitro progenitor cohorts stained positive for nestin, GFAP, and β-tubulin III, but in vivo very few cells were found that were double labeled with BrdU and one of these markers. Thus, in contrast to in vitro findings, chromaffin cells did not enhance differentiation of progenitors in vivo during the 30 days posttransplantation. The results of these studies suggest that chromaffin cells may provide neurotrophic support to enhance survival, but not differentiation, of cortical progenitor grafts in the adult CNS.

Grafting of glycidylmethacrylate onto demineralized xenogeneic bone in aqueous medium

Demineralized xenogeneic bone (DXB) was prepared from bovine cortical tibia and graft copolymerized with glycidylmethacrylate (GMA) using a combination of potassium persulfate (K2S208) and sodium metabisulfite (Na2S2O5)as redox initiating system in aqueous medium. To optimize the reaction condition, the concentrations of backbone, monomer, initiator, temperature and time were varied. The percent grafting was found to increase initially and thereafter decrease in most of the cases. The optimum temperature and time were found to be 40°C and 180 minutes, respectively. The grafting results have been discussed and a reaction mechanism is proposed. Functional groups and structural changes of the graft copolymer were determined by Fourier transform infrared (FT-IR) spectroscopic method for proof of grafting and the results are discussed.

Thigh pain after cementless total hip arthroplasty: evaluation and management.

Data from short- and long-term follow-up studies indicate that thigh pain is a significant complication after apparently successful cementless total hip arthroplasty. In most cases, reported symptoms are mild to moderate, resolve spontaneously or do not progress, and require little or no therapeutic intervention. However, persistent thigh pain may be a source of dissatisfaction or may present as severe, disabling pain. Possible causes include bone-prosthesis micromotion, excessive stress transfer to the femur, periosteal irritation, or a mismatch in Young's modulus of elasticity that increases the structural rigidity of the prosthetic stem relative to the femur. Thorough diagnostic evaluation of thigh pain is essential to rule out prosthetic infection or loosening, stress fracture, or spinal pathology as the primary source. Treatment options in the aseptic, well-fixed femoral component include medical management, revision of the femoral component, or cortical strut grafting at the tip of the implant.

Effects of DSP4 and dizolcipine on connectivity of solid E19 cortical grafts to ablated SmI region of adult rats; an in vivo electrophysiological study

The functional connectivity of an embryonic graft implanted into the lesioned somatosensory cortex and the effect of DSP4 (a selective noradrenergic neurotoxin to noradrenergic terminals) and dizolcipine (a non-competitive NMDA receptor antagonist), was studied electrophysiologically. The forepaw representational area of the rat primary somatosensory cortex was lesioned unilaterally and, 3–4 weeks later, tissue from the same region of E19 rat embryos was implanted into the cavity. At 7–9 months later, the rats were anaesthetized and single unit activity was recorded from the grafts in response to contralateral forepaw, ipsilateral hindpaw and contralateral hindpaw stimulation and compared with that obtained in control rats, in rats pretreated with dizolcipine immediately after lesioning and in rats given DSP4 24 h before transplantation. Neurones within the graft were integrated into the host brain and developed a pattern of representation similar to that of intact rats, but with a reduced proportion of neurones exhibiting short-latency response to contralateral forepaw stimulation and an increased proportion responding to stimulation of more than one paw. Pretreatment with dizolcipine did not increase short-latency responses to stimulation of contralateral forepaw stimulation however pretreatment with DSP4 reduced such responses and increased proportion of inhibitory responses. It was concluded that the noardrenergic system plays an important role in establishing host–graft connectivity. The importance of further pharmacological studies on host–graft connectivity and the relation of such connections to neural plasticity were discussed.

PERIPROSTHETIC FEMORAL FRACTURES AROUND WELL-FIXED IMPLANTS

Periprosthetic femoral fractures around hip replacements are increasingly common. When the femoral component is stable, open reduction and internal fixation is recommended in all but exceptional cases. The purpose of this study was to evaluate the outcome of treatment of fractures around stable implants with cortical onlay strut allografts with or without a plate. A survey of our four centers identified forty patients with a fracture around a well-fixed femoral stem treated with cortical onlay strut allografts without revision of the femoral component. There were fourteen men and twenty-six women, with an average age of sixty-nine years. Nineteen patients were treated with cortical onlay strut allografts alone, and twenty-one were managed with a plate and one or two cortical struts. All of the patients were followed until fracture union or until a reoperation was done. The mean duration of follow-up was twenty-eight months for thirty-nine patients. One patient, who was noncompliant with treatment recommendations, had a failure at two months because of a fracture of the plate and graft. The primary end point of the evaluation was fracture union; secondary end points included strut-to-host bone union, the amount of final bone stock, and postoperative function. Thirty-nine (98%) of the forty fractures united, and strut-to-host bone union was typically seen within the first year. There were four malunions, all of which had <10 degrees of malalignment, and one deep infection. There was no evidence of femoral loosening in any patient. All but one of the surviving patients returned to their preoperative functional level within one year. Cortical onlay strut allografts act as biological bone plates, serving both a mechanical and a biological function. The use of cortical struts, either alone or in conjunction with a plate, led to a very high rate of fracture union, satisfactory alignment, and an increase in femoral bone stock at the time of short-term follow-up. Although this study did not address the potential for later allograft remodeling, our findings suggest that cortical strut grafts should be used routinely to augment fixation and healing of a periprosthetic femoral fracture.

Interbody cages: be careful what you pack

Interbody cages: be careful what you pack

Timing of FSH-stimulation and follicular development in cryopreserved human ovarian grafts

Cryopreserved human primordial follicles grafted into immunodeficient hosts are susceptible to gonadotrophic stimulation but the optimal interval between grafting and stimulation has not been determined. The effect of stimulation with FSH at different time intervals after grafting was therefore investigated. Cryopreserved human ovarian cortical grafts from an androgen pre-treated female-to-male transsexual patient were transplanted into four groups of four non-obese, diabetic severe combined immune deficiency (NOD-SCID) mice. Ten, 12, 14 and 17 weeks after grafting, stimulation was started with daily intra-peritoneal injections of 5 IU of recombinant FSH for 14 days. Grafts were recovered and serially sectioned for counting the number of follicles and determining the different stages of development. Significantly more primary and secondary follicles were found in all stimulated groups compared with the non-stimulated control. This progression from the primordial to growing primary and secondary stages was most significant in the 14 weeks interval group. Formation of antral follicles was scarce and was only noticed in the 10 and 17 week groups. Cystic follicles and follicles with structural oocyte abnormalities were encountered in each group. Whether this phenomenon is related to the hormonal state of the tissue donor or to the cryopreservation and transplantation procedures is the subject of further investigation. It is concluded that the interval between grafting of ovarian tissue and the start of gonadotrophic stimulation may be important for an optimal follicular development after grafting.

Ovarian tissue harvested from lymphoma patients to preserve fertility may be safe for autotransplantation.

Ovarian failure is a common sequel to chemo/radiotherapy in patients successfully treated for cancer. Harvesting, cryopreserving and subsequently re-implanting ovarian cortical grafts can be used to re-establish reproductive potential in women with cancer. The safety issue, however, is of great concern because residual disease in autografted ovarian tissues might cause recrudescence of disease. A total of 30 non-obese diabetic severe combined immunodeficient (NOD/LtSz-SCID) mice were individually xenografted s.c. with frozen-thawed ovarian tissue from 18 patients with lymphoma [13 Hodgkin's lymphoma (HL) and 5 non-Hodgkin's lymphoma (NHL)]. The animals were autopsied at 16 weeks, or earlier if cachectic. The xenograft, liver, spleen, sternum, para-aortic lymph nodes and thymus were prepared for histology, immunohistochemistry and human DNA microsatellite analysis. None of the animals grafted with ovarian tissue from lymphoma patients developed disease. However, all 3 animals grafted with lymph node tissue from an NHL patient developed B-cell lymphomas that were confirmed as human in origin by DNA microsatellite analysis. Ovarian tissue harvested before high-dose chemotherapy for HL or NHL may not carry a risk of disease transmission by autotransplantation, although the possibility is difficult to exclude completely.

Altered expression of apolipoprotein E, amyloid precursor protein and presenilin-1 is associated with chronic reactive gliosis in rat cortical tissue

A major characteristic feature of Alzheimer’s disease is the formation of compact, extracellular deposits of β-amyloid (senile plaques). These deposits are surrounded by reactive astrocytes, microglia and dystrophic neurites. Mutations in three genes have been implicated in early-onset familial Alzheimer’s disease. However, inflammatory changes and astrogliosis are also believed to play a role in Alzheimer’s pathology. What is unclear is the extent to which these factors initiate or contribute to the disease progression. Previous rat studies demonstrated that heterotopic transplantation of foetal cortical tissue onto the midbrain of neonatal hosts resulted in sustained glial reactivity for many months. Similar changes were not seen in cortex-to-cortex grafts. Using this model of chronic cortical gliosis, we have now measured reactive changes in the levels of the key Alzheimer’s disease proteins, namely the amyloid precursor protein, apolipoprotein E and presenilin-1. These changes were visualised immunohistochemically and were quantified by western blot analysis. We report here that chronic cortical gliosis in the rat results in a sustained increase in the levels of apolipoprotein E and total amyloid precursor protein. Reactive astrocytes in heterotopic cortical grafts were immunopositive for both of these proteins. Using a panel of amyloid precursor protein antibodies we demonstrate that chronic reactive gliosis is associated with alternative cleavage of the peptide. No significant changes in apolipoprotein E or amyloid precursor protein expression were seen in non-gliotic cortex-to-cortex transplants. Compared to host cortex, the levels of both N-terminal and C-terminal fragments of presenilin-1 were significantly lower in gliotic heterotopic grafts. The changes described here largely mirror those seen in the cerebral cortex of humans with Alzheimer’s disease and are consistent with the proposal that astrogliosis may be an important factor in the pathogenesis of this disease.

Follicular growth in fresh and cryopreserved human ovarian cortical grafts transplanted to immunodeficient mice

Objective: To investigate follicle growth in fresh and cryopreserved human ovarian cortical grafts transplanted to immunodeficient mice. Study design: Fresh or frozen-thawed human ovarian cortex was grafted subcutaneously or under the kidney capsule of 43 mice (35 nude mice and eight SCID mice), 14 of which were non-stimulated controls, 21 injected intra-peritoneally with gonadotrophins during 2 weeks and eight injected during 3 months. Follicle count was compared by Chi-square. Results: Proportions of primordial follicles were significantly lower in grafts than in the tissue before transplantation in gonadotrophin-stimulated mice (37% versus 79%), but not in non-stimulated mice (51% versus 74%). Proportions of primary and secondary follicles were increased after transplantation indicating early follicular growth. One antral follicle was observed in a graft in a mouse stimulated for 3 months. Conclusion: Primordial follicles in fresh or frozen-thawed human ovarian cortex transplanted under the kidney capsule or subcutaneously can grow and are responsive to hormonal stimulation. Condensation: Primordial follicles in fresh and cryopreserved human ovarian cortical grafts can initiate growth after transplantation to immunodeficient mice