SPECIAL semi‐LASER with lipid artifact compensation for 1H MRS at 7 T

The measurement of full metabolic profiles at ultrahigh fields including low concentrated or fast‐relaxing metabolites is usually achieved by applying short echo time sequences. One sequence beside stimulated echo acquisition mode that was proposed in this regard is spin echo full intensity‐acquired localized spectroscopy. Typical problems that are still persistent for spin echo full intensity‐acquired localized spectroscopy are B₁ inhomogeneities especially for signal acquisition with surface coils and chemical shift displacement artifacts due to limited B₁ amplitudes when using volume coils. In addition, strong lipid contaminations in the final spectrum can occur when only a limited number of outer volume suppression pulses is used. Therefore, an adiabatic short echo time (= 19 ms) spin echo full intensity‐acquired localized spectroscopy semilocalization by adiabatic selective refocusing sequence is presented that is less sensitive to strong B₁ variations and that offers increased excitation and refocusing pulse bandwidths than regular spin echo full intensity acquired localized spectroscopy. Furthermore, the existence of the systematic lipid artifact is identified and linked to unfavorable effects due to the preinversion localization pulse. A method to control this artifact is presented and validated in both phantom and in vivo measurements. The viability of the proposed sequence was further assessed for in vivo measurements by scanning 17 volunteers using a surface coil and moreover acquiring additional volume coil measurements. The results show well‐suppressed lipid artifacts, good signal‐to‐noise ratio, and reproducible fitting results in accordance with other published studies. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Mesenchymal stem cells for the treatment of cartilage lesions: from preclinical findings to clinical application in orthopaedics

Purpose

The aim of this systematic review is to examine the available clinical evidence in the literature to support mesenchymal stem cell (MSC) treatment strategies in orthopaedics for cartilage defect regeneration.

Methods

The research was performed on the PubMed database considering the English literature from 2002 and using the following key words: cartilage, cartilage repair, mesenchymal stem cells, MSCs, bone marrow concentrate (BMC), bone marrow-derived mesenchymal stem cells, bone marrow stromal cells, adipose-derived mesenchymal stem cells, and synovial-derived mesenchymal stem cells.

Results

The systematic research showed an increasing number of published studies on this topic over time and identified 72 preclinical papers and 18 clinical trials. Among the 18 clinical trials identified focusing on cartilage regeneration, none were randomized, five were comparative, six were case series, and seven were case reports; two concerned the use of adipose-derived MSCs, five the use of BMC, and 11 the use of bone marrow-derived MSCs, with preliminary interesting findings ranging from focal chondral defects to articular osteoarthritis degeneration.

Conclusions

Despite the growing interest in this biological approach for cartilage regeneration, knowledge on this topic is still preliminary, as shown by the prevalence of preclinical studies and the presence of low-quality clinical studies. Many aspects have to be optimized, and randomized controlled trials are needed to support the potential of this biological treatment for cartilage repair and to evaluate advantages and disadvantages with respect to the available treatments.

Level of evidence

IV.     

Increased phosphorylation of skeletal muscle glycogen synthase at NH2-terminal sites during physiological hyperinsulinemia in type 2 diabetes

In type 2 diabetes, insulin activation of muscle glycogen synthase (GS) is impaired. This defect plays a major role for the development of insulin resistance and hyperglycemia. In animal muscle, insulin activates GS by reducing phosphorylation at both NH(2)- and COOH-terminal sites, but the mechanism involved in human muscle and the defect in type 2 diabetes remain unclear. We studied the effect of insulin at physiological concentrations on glucose metabolism, insulin signaling and phosphorylation of GS in skeletal muscle from type 2 diabetic and well-matched control subjects during euglycemic-hyperinsulinemic clamps. Analysis using phospho-specific antibodies revealed that insulin decreases phosphorylation of sites 3a + 3b in human muscle, and this was accompanied by activation of Akt and inhibition of glycogen synthase kinase-3alpha. In type 2 diabetic subjects these effects of insulin were fully intact. Despite that, insulin-mediated glucose disposal and storage were reduced and activation of GS was virtually absent in type 2 diabetic subjects. Insulin did not decrease phosphorylation of sites 2 + 2a in healthy human muscle, whereas in diabetic muscle insulin infusion in fact caused a marked increase in the phosphorylation of sites 2 + 2a. This phosphorylation abnormality likely caused the impaired GS activation and glucose storage, thereby contributing to skeletal muscle insulin resistance, and may therefore play a pathophysiological role in type 2 diabetes.     

Patient-controlled epidural analgesia reduces analgesic requirements compared to continuous epidural infusion after major abdominal surgery

PURPOSE: To compare the quality of pain relief and incidence of side effects between 24-hr postoperative continuous epidural infusion (CEI) and subsequent patient-controlled epidural analgesia (PCEA) with different analgesics after major abdominal surgery. METHODS: Twenty-eight women undergoing extended gynecological tumour surgery received postoperative CEI with 0.15 mL x kg(-1) x hr(-1) 0.2% ropivacaine (R: n = 14) or 0.125% bupivacaine plus 0.5 micro g x mL(-1) sufentanil (BS: n = 14) during 24 postoperative hours. Twenty-four hours later, postoperative pain management was switched to PCEA without background infusion and 5 mL single bolus application of R or BS every 20 min at most. Visual analogue scales (VAS; 1-100 mm) were assessed by patients at rest and on coughing after 24 hr of CEI and PCEA. Side effects, doses of local anesthetics and opioids were recorded and plasma concentrations of total and unbound ropivacaine and bupivacaine were measured. RESULTS: Patients required lower doses of each respective analgesic medication with PCEA (R: 108 +/- 30 mL; BS: 110 +/- 28 mL) than with CEI (R: 234 +/- 40; BS: 260 +/- 45; P < 0.01). Ropivacaine plasma concentrations were lower 24 hr after PCEA when compared with CEI (P < 0.01). No patient after PCEA but two after CEI (n = 4; NS) presented motor block. PCEA with R provided better postoperative pain relief than CEI (37 +/- 32 vs 59+/-27, P < 0.05). No difference in parenteral opioid rescue medication between CEI and PCEA was seen. CONCLUSION: PCEA in comparison to preceding CEI provides equivalent analgesia with lower local anesthetic doses and plasma levels, and without motor blocking side effects, irrespective of the applied drug regimen.     

Prospective, Randomized, Multi-Center Trial of Antibody Induction Therapy in Simultaneous Pancreas-Kidney Transplantation

A randomized, multicenter, prospective study was conducted at 18 pancreas transplant centers in the United States to determine the role of induction therapy in simultaneous pancreas-kidney (SPK) transplantation. One hundred and 74 recipients were enrolled: 87 recipients each in the induction and noninduction treatment arms. Maintenance immunosuppression consisted of tacrolimus, mycophenolate mofetil, and corticosteroids. There were no statistically significant differences between treatment groups for patient, kidney, and pancreas graft survival at 1-year. The 1-year cumulative incidence of any treated biopsy-confirmed or presumptive rejection episodes (kidney or pancreas) in the induction and noninduction treatment arms was 24.6% and 31.2% (p = 0.28), respectively. The 1-year cumulative incidence of biopsy-confirmed, treated, acute kidney allograft rejection in the induction and noninduction treatment arms was 13.1% and 23.0% (p = 0.08), respectively. Biopsy-confirmed kidney allograft rejection occurred later post-transplant and appeared to be less severe among recipients that received induction therapy. The highest rate of Cytomegalovirus (CMV) viremia/syndrome was observed in the subgroup of recipients who received T-cell depleting antibody induction and received organs from CMV serologically positive donors. Decisions regarding the routine use of induction therapy in SPK transplantation must take into consideration its differential effects on risk of rejection and infection.     

光学成像示踪细胞

因光具适应性、灵敏性、分辨率和无创性,其作为科学研究工具由来已久,也是光学成像(optical imaging,OI的基础。光学成像包括多种成像技术及方法,具有成像快速     

Histological osseointegration of Tutobone<Superscript>®</Superscript>: first results in human

The aim of this study was to evaluate the histological and radiological osseointegration characteristics of implanted solvent-preserved cancellous bovine bone substitution material Tutobone after opening-wedge osteotomy and hip arthroplasty in human. The baseline hypothesis connected to the usage of bovine bone substitute materials is the assumption of temporary structural support, integration in the surrounding bone, bioresorption and replacement with vital bone. This hypothesis is based on numerous studies evaluating sintered bovine grafts showing good osseointegration and stability. Studies analyzing cancellous bovine grafts such as Tutobone hardly exist. The only rabbit defect model showed 100% remodeling of Tutobone after 26 weeks. However, no histological data are available on application of this xenograft in patients. In this study, nine patients biopsies were collected about 11 months after application of Tutobone. Unlike animal studies, the results showed incorporated avital graft remnants (47%) as well as new bone formation (53%) of the total mineralized area. Radiological evaluation confirmed increasing signs of osseointegration and an incomplete resorption. In conclusion, degradation and replacement of bovine graft seems to be less accelerated in patients than the animal study indicated. Nevertheless, Tutobone shows an excellent biocompatibility, good osteoconductive characteristics and may represent a useful alternative to autogenous graft.     

Alport syndrome associated with diffuse leiomyomatosis: COL4A5-COL4A6 deletion associated with a mild form of Alport nephropathy.

BACKGROUND: The X-linked Alport syndrome (AS) is an inherited nephropathy due to mutations in the COL4A5 gene, encoding the alpha5 chain of type IV collagen, a major component of the glomerular basement membrane (GBM). Here, we report a new kindred with the rare association of X-linked AS and diffuse leiomyomatosis (DL), which is a tumourous process involving smooth muscle cells of the oesophagus, the tracheobronchial tree and, in females, the genital tract. For this syndrome, an almost constant association of large COL4A5 rearrangements with a severe juvenile form of nephropathy has been described for male patients. METHODS: DNA rearrangement at the COL4A5-COL4A6 locus was studied in several members of this family using polymerase chain reaction and pulsed field gel electrophoresis. Furthermore, immunohistochemical staining of tumour and skin samples was performed. RESULTS: The affected patients in this family carry a 120 kb deletion by which the COL4A5 exon 1 and COL4A6 exons 1, 1', and 2 are removed. Immunohistochemical investigation of a skin biopsy of an affected male patient confirmed the absence of both the alpha5 and the alpha6 chains of type IV collagen in the basement membrane of the skin. Surprisingly, both affected male patients had a rather mild renal phenotype. CONCLUSIONS: This report shows that, contrary to what has been reported to date, patients suffering from AS associated with DL can be associated with a late onset renal failure (adult) form of nephropathy.     

Complications of plate fixation in metacarpal fractures

BACKGROUND: The objective of this study is to assess the complications after open reduction and plate fixation of extra-articular metacarpal fractures. METHODS: We retrospectively reviewed the clinical and radiologic records of 129 consecutive patients with 157 metacarpal fractures treated by open reduction and internal fixation with plates between 1993 and 1999. Intra-articular fractures and fractures of the thumb metacarpal were excluded. Eighty-one patients (64 men and 17 women) with 104 fractures were available for review, at an average follow-up of 13.6 months (range, 6-27 months). RESULTS: Twenty-eight patients (35%) and 33 fractures (32%) had one or more complications, including difficulty with fracture healing (12 patients [15%]), stiffness (eight patients [10%]), plate loosening or breakage (seven patients [8%]), complex regional pain syndrome (two patients), and one patient who developed a deep infection. CONCLUSION: Despite technical advances in implant material, design, and instrumentation, plate fixation of metacarpal fractures remains fraught with complications and unsatisfactory results.