Mild aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)-type reactions also present in patients with failed knee prostheses.

Aims: Metal particles detached from metal-on-metal hip prostheses (MoM-THA) have been shown to cause inflammation and destruction of tissues. To further explore this, we investigated the histopathology (aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) score) and metal concentrations of the periprosthetic tissues obtained from patients who underwent revision knee arthroplasty. We also aimed to investigate whether accumulated metal debris was associated with ALVAL-type reactions in the synovium. Methods: Periprosthetic metal concentrations in the synovia and histopathological samples were analyzed from 230 patients from our institution from October 2016 to December 2019. An ordinal regression model was calculated to investigate the effect of the accumulated metals on the histopathological reaction of the synovia. Results: Median metal concentrations were as follows: cobalt: 0.69 µg/g (interquartile range (IQR) 0.10 to 6.10); chromium: 1.1 µg/g (IQR 0.27 to 4.10); and titanium: 1.6 µg/g (IQR 0.90 to 4.07). Moderate ALVAL scores were found in 30% (n = 39) of the revised knees. There were ten patients with an ALVAL score of 6 or more who were revised for suspected periprosthetic joint infection (PJI), aseptic loosening, or osteolysis. R2 varied between 0.269 and 0.369 for the ordinal regression models. The most important variables were model type, indication for revision, and cobalt and chromium in the ordinal regression models. Conclusion: We found that metal particles released from the knee prosthesis can accumulate in the periprosthetic tissues. Several patients revised for suspected culture-negative PJI had features of an ALVAL reaction, which is a novel finding. Therefore, ALVAL-type reactions can also be found around knee prostheses, but they are mostly mild and less common than those found around metal-on-metal prostheses.

Histopathological patterns seen around failed metal-on-metal hip replacements: Cluster and latent class analysis of patterns of failure.

We aimed to establish latent subtypes of histopathological patterns in failed metal-on-metal hip replacements. Tissue samples of the synovia from the neocapsule were retrieved from 284 revised ASR (Articular Surface Replacement) hip replacements and analyzed histologically. Hierarchical cluster analysis and polytomous latent class analysis were performed to establish the underlying structure and relationships of the histological observations and to find similar cohorts of cases. Clustering analyses suggested four distinct subtypes that could be readily and reasonably labeled and mapped against a recent consensus statement. The first two subtypes showed synovial necrosis, lymphocyte sheets, and abundant or thin histiocyte sheets. In addition, the first subtype showed abundant germinal centers and no metal particles either extracellularly or intracellularly. Metal particles were, however, seen in the second subtype. Hence, the first subtype was labeled "immunologic Type IV neosynovitis" and the second subtype "abrasion-induced inflammatory lymphocytic Type I neosynovitis." The third and fourth subtypes showed no perivascular and diffuse lymphocytes, but a higher number of metal particles intracellularly and extracellularly. The third subtype had synovial necrosis along with granulomas and was labeled "abrasion-induced necrotic Type I neosynovitis," whereas the fourth subtype had readily intact synovial lining, and this subtype was labeled "abrasion-induced foreign body Type I neosynovitis." Histopathological findings in failed MoM hips are not just one wide entity. These hips evince four different histological patterns that also differ at the macroscopic level. Moreover, the often stated "ALVAL-type reaction" seems to be dualistic in nature, which is a novel finding.

Host-specific factors affect the pathogenesis of adverse reaction to metal debris.

BACKGROUND: Adverse Reaction to Metal Debris (ARMD) is a major reason for revision surgeries in patients with metal-on-metal (MoM) hip replacements. Most failures are related to excessively wearing implant producing harmful metal debris (extrinsic factor). As ARMD may also occur in patients with low-wearing implants, it has been suggested that there are differences in host-specific intrinsic factors contributing to the development of ARMD. However, there are no studies that have directly assessed whether the development of ARMD is actually affected by these intrinsic factors. METHODS: We included all 29 patients (out of 33 patients) with sufficient data who had undergone bilateral revision of ASR MoM hips (58 hips) at our institution. Samples of the inflamed synovia and/or pseudotumour were obtained perioperatively and sent to histopathological analysis. Total wear volumes of the implants were assessed. Patients underwent MARS-MRI imaging of the hips preoperatively. Histological findings, imaging findings and total wear volumes between the hips of each patient were compared. RESULTS: The difference in wear volume between the hips was clinically and statistically significant (median difference 15.35 mm3, range 1 to 39 mm3, IQR 6 to 23 mm3) (p < 0.001). The median ratio of total wear volume between the hips was 2.0 (range 1.09 to 10.0, IQR 1.67 to 3.72). In majority of the histological features and in presence of pseudotumour, there were no differences between the left and right hip of each patient (p > 0.05 for all comparisons). These features included macrophage sheet thickness, perivascular lymphocyte cuff thickness, presence of plasma cells, presence of diffuse lymphocytic infiltration and presence of germinal centers. CONCLUSIONS: Despite the significantly differing amounts of wear (extrinsic factor) seen between the sides, majority of the histological findings were similar in both hips and the presence of pseudotumour was symmetrical in most hips. As a direct consequence, it follows that there must be intrinsic factors which contribute to the symmetry of the findings, ie. the pathogenesis of ARMD, on individual level. This has been hypothesized in the literature but no studies have been conducted to confirm the hypothesis. Further, as the threshold of metal debris needed to develop ARMD appears to be largely variable based on the previous literature, it is likely that there are between-patient differences in these intrinsic factors, ie. the host response to metal debris is individual.

Tibia Adamantinoma Resection and Reconstruction with a Custom-Made Total Tibia Endoprosthesis: A Case Report with 8-Year Follow-Up.

This case study describes a total tibia resection and reconstruction with a custom-made endoprosthetic replacement (EPR) and a long-term, 8-year follow-up. The patient underwent a total tibia adamantinoma resection in 2009. Reconstruction was performed with a custom-made total tibia EPR, where both the knee joint and ankle joint were reconstructed. Two muscle flaps, latissimus dorsi free flap and a pedicled medial gastrocnemius flap, were used for soft tissue reconstruction. The patient returned to normal life as a kindergarten teacher, without complications for eight years. This case demonstrated the importance of successful multidisciplinary teamwork in close collaboration with industry. In our best knowledge, no over 2 years of follow-up of total tibia replacement reports have been published.

Solitary juvenile xanthogranuloma in the spine pretreated with neoadjuvant denosumab therapy followed by surgical resection in a 5-year-old child: case report and literature review.

PURPOSE: We present a case report that describes neoadjuvant denosumab therapy initiated in a child with a solitary giant cell-rich juvenile xanthogranuloma tumor involving the spine, and review the current literature. METHODS: A giant cell-rich histiocytic lesion involving the 11th thoracic vertebral body was identified in a healthy 5-year-old girl with persistent back and pelvic pain for several months. Imaging examinations and an open biopsy were performed to obtain a definite pathologic diagnosis. As the tumor appeared to be aggressive in nature, we administered adjuvant therapy with denosumab preoperatively and then performed a total spondylectomy. RESULTS: Histopathology confirmed that the tumor was juvenile xanthogranuloma. No tumor metastases or recurrence were detected at the 3-year follow-up, and the patient was asymptomatic. CONCLUSIONS: In giant cell-rich tumors, denosumab is occasionally used as neoadjuvant or adjuvant therapy, especially for tumors in difficult locations or with substantial soft tissue extensions. Rare adverse events in children include skin infections and disruption of calcium homeostasis. Surgical treatment is aimed at removing the tumor and relieving the symptomatic spinal cord compression. Use of denosumab as neoadjuvant therapy for juvenile xanthogranuloma involving the spine has not been reported previously.

Association between periprosthetic tissue metal content, whole blood and synovial fluid metal ion levels and histopathological findings in patients with failed metal-on-metal hip replacement.

Adverse Reaction to Metal Debris (ARMD) is a major cause of implant failure leading to revision surgery in patients with metal-on-metal (MoM) hip arthroplasties. However, the pathogenesis and its association to implant wear are poorly understood and previous studies have yielded discrepant results. We sought to investigate the associations between histological findings, whole blood and synovial fluid metal ion concentrations and periprosthetic tissue metal concentrations in patients with MoM total hip replacements and hip resurfacings revised for ARMD. 107 hips in total were included in our study. Of these, 87 were total hip replacements and 20 were hip resurfacings, respectively. We found that whole blood, synovial fluid and periprosthetic tissue metal concentrations correlated poorly with histological findings. We suggest that the lack of a clear association between histological findings and wear measures in the present study as well as in previous studies is mostly influenced by variability in patient susceptibility. However, patients presenting with perivascular lymphocytic infiltration had lower chromium concentration in their periprosthetic tissues than patients with no perivascular lymphocytic infiltration. This may reflect the role of metal hypersensitivity in implant failure in these patients. Patients with total hip replacements evinced more necrosis and lymphocytic infiltration in their tissues than patients with hip resurfacings. This suggests that trunnion wear debris is more cytotoxic and/or immunogenic than bearing wear debris leading to higher failure rates seen in patients with total hip replacements.

Analysis of bearing wear, whole blood and synovial fluid metal ion concentrations and histopathological findings in patients with failed ASR hip resurfacings.

BACKGROUND: Adverse Reaction to Metal Debris (ARMD) is still a major reason for revision surgeries in patients with metal-on-metal (MoM) hip replacements. ARMD consists of a wide range of alterations in periprosthetic tissues, most important of which are metallosis, inflammation, pseudotumors and necrosis. Studies investigating histopathological findings and their association to implant wear or indirect measures of wear have yielded inconsistent results. Therefore, we aimed to investigate bearing surface wear volume, whole blood and synovial fluid metal ion concentrations, histopathological findings in periprosthetic tissues and their associations. METHODS: Seventy-eight patients with 85 hips revised for ARMD were included in the study. Prior to revision surgery, all patients had whole blood chromium and cobalt ion levels assessed. In revision surgery, a synovial fluid sample was taken and analyzed for chromium and cobalt. Periprosthetic tissue samples were taken and analyzed for histopathological findings. Explanted implants were analyzed for bearing wear volume of both acetabular cup and femoral head components. RESULTS: Volumetric wear of the failed components was highly variable. The total wear volume of the head and cup had a strong correlation with whole blood chromium and cobalt ion concentrations (Cr: ρ = 0.80, p < 0.001 and Co: ρ = 0.84, p < 0.001) and a bit weaker correlation with fluid chromium and cobalt ion concentrations (Cr: ρ = 0.50, p < 0.01 and Co: ρ = 0.41, p = 0.027). Most tissues displayed only low-to-moderate amounts of macrophages and lymphocytes. Total wear volume correlated with macrophage sheet thickness (ρ = 0.25, p = 0.020) and necrosis (ρ = 0.35, p < 0.01). Whole blood chromium and cobalt ion concentrations had similar correlations. Lymphocyte cuff thickness did not correlate with either total wear volume or whole blood metal ion concentrations, but correlated with the grade of necrosis. CONCLUSIONS: Bearing wear volume correlated with blood metal ion levels and the degree of necrosis and macrophage infiltration in periprosthetic tissues suggesting a dose-response relationship. Whole blood metal ion levels are a useful tool for clinician to estimate bearing wear and subsequent tissue response.

Outcomes After Flexor Tendon Repair Combined With the Application of Human Amniotic Membrane Allograft.

PURPOSE: Clinically proven methods to prevent adhesion formation after flexor tendon repair have not yet been established. The aim of this pilot study was to assess the feasibility of amniotic membrane allograft as a mechanical barrier to decrease adhesion formation. METHODS: Ten patients having flexor tendon injuries were planned to be recruited to the pilot study. The operative treatment consisted of tendon repair and fixation of amniotic membrane allograft around the repaired tendon. The primary outcome variable was the range of motion of the operated finger 6 months after the operation. Patients were monitored for infections and repair failures. RESULTS: The study was terminated owing to unfavorable results after treatment of 5 patients. One patient had extensive stiffness and was subjected to tenolysis and joint release. Histopathological analysis of the tendon sheath revealed focal fibrosis. Another patient had a repair failure. The other 3 patients had fair to good results. CONCLUSIONS: It seems improbable that the use of amniotic membrane allograft would yield clinically relevant improvement compared with the existing techniques. However, it remains unclear whether the unfavorable results are associated with technical factors, amniotic membrane allograft itself, or an irregular distribution of complications. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

High blood metal ion levels in 19 of 22 patients with metal-on-metal hinge knee replacements.

Background and purpose - There has been increasing alarm regarding metal-on-metal (MoM) joint replacements leading to elevated levels of metal ions and adverse reactions to metal debris (ARMDs). There is little information available concerning the prevalence of and risk factors for these adverse reactions, except with MoM hip joint replacements. We determined the levels of metal ions in blood and the rate of revision due to ARMDs in patients treated with MoM hinge total knee arthroplasty (TKA). Patients and methods - 22 patients with TKAs and MoM hinge connecting mechanisms were studied for whole-blood chromium and cobalt levels at 6 months, 1 year, and/or ≥2 years after surgery. Possible ARMDs were investigated by MRI. 12 patients with TKAs and metal-on-polyethylene (MoP) connecting mechanisms served as controls. Results - The cobalt levels were over 5 ppb in 19 of the 22 patients in the MoM group and in 1 of the 12 patients in the MoP group. The chromium levels were over 5 ppb in 11 of the 22 patients in the MoM group and in none of the 12 patients in the MoP group. Pseudotumors were operated in 4 of the 22 patients in the MoM group and in none of the patients in the MoP group. Interpretation - Our results clearly show that the MoM hinge TKA carries a high risk of increased levels of systemic metal ions and also local ARMD, leading to complicated knee revisions. We therefore discourage the use of MoM hinge TKA.

Mesotheliomas show higher hyaluronan positivity around tumor cells than metastatic pulmonary adenocarcinomas.

Hyaluronan is a unique glycosaminoglycan of the extracellular matrix, abundant in normal connective tissues but highly increased in many pathological conditions like cancer. Mesothelioma, one of the most malignant cancer types, is associated with high content of hyaluronan, with elevated levels of hyaluronan in pleural effusions and serum of the patients. Metastatic lung adenocarcinomas are typically less aggressive and have a better prognosis as compared to mesotheliomas, a reason why it is highly important to find reliable tools to differentiate these cancer types. The main purpose of this study was to evaluate the amount of hyaluronan, hyaluronan producing synthases (HAS's) and hyaluronan receptor CD44, in mesothelioma and metastatic lung adenocarcinomas. Furthermore, we wanted to clarify the role of hyaluronan, CD44 and HAS's as putative markers for differentiating malignant mesothelioma from metastatic lung adenocarcinomas. The main finding of this study was that mesotheliomas are significantly more positive for hyaluronan staining than metastatic adenocarcinomas. Unexceptionally, a trend of CD44 positivity of stromal cells was higher in adenocarcinomas as compared to mesotheliomas. However, no statistically significant differences were found between the staining of any of the HAS isoenzymes either in tumor cells or stromal cells of different groups of cases. The results show that there are significant differences in hyaluronan content between metastatic lung adenocarcinomas and mesotheliomas. However, as previous studies have suggested, hyaluronan alone is not a sufficient independent marker for diagnostic differentiation of these cancer types, but could be utilized as a combination together with other specific markers.

Diagnostic utility of joint fluid metal ion measurement for histopathological findings in metal-on-metal hip replacements.

BACKGROUND: In vivo assessment of inflammatory responses in the synovia of patients with MoM hip replacements would be useful in the determination of the prognosis of the hip replacement. Aims of the study was to investigate the correlation between cobalt and chrome levels in joint fluid with histopathological findings and the predictive ability of metal ion levels for these findings. METHODS: In 163 revision surgeries (141 ASR THAs and 22 ASR hip resurfacings) joint fluid chrome and cobalt levels were assessed and histological analysis of synovial tissues was performed. Histological analysis included assessment of histiocytes, particle load, surface necrosis, lymphocyte cuffs and ALVAL-score. RESULTS: Surface necrosis correlated positively with cobalt levels both in both groups. Neither chrome nor cobalt level had even fair discriminative ability to predict the presence or severity of any histological finding in the THA group. In the hip resurfacing group, cobalt level had good discriminative ability to predict the presence of perivascular lymphocytes and ALVAL-score of ≥ 7 whereas chrome had good discriminative ability to predict surface necrosis, metal particle load and ALVAL-score of ≥ 7. CONCLUSIONS: Measurement of metal ion levels following joint fluid aspirate offers no relevant information with regard to histopathological findings in patients with large-diameter MoM THAs. Limited information may be gained from assessment of joint fluid metal ion levels in patients with hip resurfacings, but disadvantages of an aspirate must be carefully reviewed.

Genetic alterations in periprosthetic soft-tissue masses from patients with metal-on-metal hip replacement.

Adverse soft tissue reactions in patients with metal-on-metal (MoM) hip replacement are associated with cobalt (Co) and chromium (Cr) particles released from the implant. Exposing the patients to long periods of increased metal ions concentrations resulting from the wear of these implants poses an increased risk of genotoxicity/mutagenicity. A variable proportion of patients develop periprosthetic soft-tissue masses or pseudotumors at the site of the implant. There is a concern that exposure to increased metal ions could increase the risk of cancer. In order to investigate whether the periprosthetic soft-tissue mass harbours any cancer- related genetic alterations, we studied DNA isolated from periprosthetic tissues of 20 patients with MoM hip replacement, for copy number alterations and mutations in hotspot regions of 50 cancer genes using aCGH and amplicon-based next generation sequencing. Our results showed copy number gains at 12q14.3 and 21q21.1in tumour from patient diagnosed with liposarcoma. Copy number alterations in periprosthetic tissues were seen in three other patients, one had a region of gain at 9q24.1 affecting JAK2 and INSL6, and two patients had region of gain at 6p21.1, affecting RUNX2. Mutation analysis showed V1578del mutation in NOTCH1 in two patients. The copy number alterations and mutations seen in periprosthetic soft-tissue masses are earlier reported in either haematological malignancies or in osteoblast related bone dysplasia. The presence of genetic anomalies was associated with longer in-situ time of the implant. Our findings warrant the need of similar studies in larger patient cohorts to evaluate the risk of development of neoplastic alterations in periprosthetic tissues of patients with MoM hip replacement.

Dietary phosphate binding and loading alter kidney angiotensin-converting enzyme mRNA and protein content in 5/6 nephrectomized rats.

BACKGROUND: Vitamin D receptor activation with paricalcitol can modulate the transcription of renin-angiotensin system components in the surgical 5/6 nephrectomy rat model (5/6 NX) of chronic renal insufficiency. We tested the hypothesis whether dietary modification of phosphate influences kidney renin-angiotensin system gene expression at the mRNA level in 5/6 NX rats. METHODS: Fifteen weeks after surgery, rats were given control diet (0.3% calcium, 0.5% phosphate), phosphate-lowering diet (3% calcium as carbonate) or high-phosphate diet (1.5%) for 12 weeks. Sham-operated rats were on control diet. RESULTS: Blood pressure, plasma phosphate, parathyroid hormone, glomerulosclerosis, tubulointerstitial damage, and FGF-23 were increased in remnant kidney rats, whereas creatinine clearance was decreased. Phosphate, parathyroid hormone, glomerulosclerosis, tubulointerstitial damage, and FGF-23 were further elevated by the high-phosphate diet, but were reduced by the phosphate-lowering diet. Plasma calcium was increased with the phosphate-lowering diet and decreased with the high-phosphate diet. Remnant kidney rats on control diet showed upregulated kidney angiotensin-converting enzyme (ACE) and angiotensin (Ang) IV receptor (AT(4)) transcription, while ACE2, Ang II type 2 receptor and renin receptor transcription were downregulated in comparison with sham rats. Phosphate-lowering diet reduced whereas high-phosphate diet increased kidney ACE, and these effects were observed at both mRNA and protein levels. Dietary phosphate loading also resulted in lower AT(1a) gene transcription. CONCLUSION: Dietary phosphate loading was associated with elevated kidney ACE expression, increased tissue damage and lower AT(1a) transcription in 5/6 NX rats. Phosphate binding with 3% calcium carbonate had opposite effects on ACE and kidney damage.

Genes involved in systemic and arterial bed dependent atherosclerosis--Tampere Vascular study.

BACKGROUND: Atherosclerosis is a complex disease with hundreds of genes influencing its progression. In addition, the phenotype of the disease varies significantly depending on the arterial bed. METHODOLOGY/PRINCIPAL FINDINGS: We characterized the genes generally involved in human advanced atherosclerotic (AHA type V-VI) plaques in carotid and femoral arteries as well as aortas from 24 subjects of Tampere Vascular study and compared the results to non-atherosclerotic internal thoracic arteries (n=6) using genome-wide expression array and QRT-PCR. In addition we determined genes that were typical for each arterial plaque studied. To gain a comprehensive insight into the pathologic processes in the plaques we also analyzed pathways and gene sets dysregulated in this disease using gene set enrichment analysis (GSEA). According to the selection criteria used (>3.0 fold change and p-value <0.05), 235 genes were up-regulated and 68 genes down-regulated in the carotid plaques, 242 genes up-regulated and 116 down-regulated in the femoral plaques and 256 genes up-regulated and 49 genes down-regulated in the aortic plaques. Nine genes were found to be specifically induced predominantly in aortic plaques, e.g., lactoferrin, and three genes in femoral plaques, e.g., chondroadherin, whereas no gene was found to be specific for carotid plaques. In pathway analysis, a total of 28 pathways or gene sets were found to be significantly dysregulated in atherosclerotic plaques (false discovery rate [FDR] <0.25). CONCLUSIONS: This study describes comprehensively the gene expression changes that generally prevail in human atherosclerotic plaques. In addition, site specific genes induced only in femoral or aortic plaques were found, reflecting that atherosclerotic process has unique features in different vascular beds.

Expression of matrix metalloproteinases-2, -8, -13, -26, and tissue inhibitors of metalloproteinase-1 in human osteosarcoma.

Osteosarcoma (OS) is among most common malignant tumour of bone. Matrix metalloproteinases (MMPs) are predominantly associated with poor prognosis of several cancers, although some of them, like MMP-8, seem to have a protective role in some cancers. We analyzed the distribution patterns of MMP-2, -8, -13, -26, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 in 25 OS patients. MMP-2, -8, -13, -26 and TIMP-1 were mostly detected in sarcoma cells. Response to chemotherapy affected the amount of MMP-2, -8, and -13 in resection sections when compared to biopsies: patients with excellent or good response had less positivity to MMP-2 in chemotherapy samples than those with moderate or poor response. We conclude that MMP-2, -8, -13, -26, and TIMP-1 are expressed in OS tissue, and all, except protective MMP-8, were also found in metastases indicating that MMPs and TIMP-1 can participate in the OS progression.

ADAM8 and its single nucleotide polymorphism 2662 T/G are associated with advanced atherosclerosis and fatal myocardial infarction: Tampere vascular study.

OBJECTIVE: Previously, we scanned all 23,000 human genes for differential expression between normal and atherosclerotic tissues and found the involvement of ADAM8. METHODS: We investigated the expression of ADAM8 mRNA and protein level in human atherosclerotic tissues and non-atherosclerotic internal thoracic arteries as well as the association of ADAM8 2662 T/G single nucleotide polymorphism (SNP) with the extent of coronary atherosclerosis and with the risk of fatal myocardial infarction. RESULTS: ADAM8 mRNA was up-regulated in carotid, aortic, and femoral atherosclerotic plaques (n=24) when compared with non-atherosclerotic arteries. ADAM8 protein expression was increased in advanced atherosclerotic plaques as compared to control vessels wherein it was localized to macrophages and smooth muscle cells The G allele carriers of the ADAM8 2662 T/G SNP had significantly larger areas of fibrotic, calcified, and complicated plaques in coronary arteries (P=0.027, P=0.011, and P=0.011, respectively) and significantly higher occurrence of myocardial infarction (MI) (P=0.004) and fatal pre-hospital MI (P=0.003) than did the TT homozygotes. CONCLUSION: ADAM8 is a promising candidate to be involved in atherosclerosis, and its 2662 T/G allelic variant significantly associates with advanced atherosclerotic lesion areas and MI.

Enhanced polyamine catabolism alters homeostatic control of white adipose tissue mass, energy expenditure, and glucose metabolism.

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1 alpha) is an attractive candidate gene for type 2 diabetes, as genes of the oxidative phosphorylation (OXPHOS) pathway are coordinatively downregulated by reduced expression of PGC-1 alpha in skeletal muscle and adipose tissue of patients with type 2 diabetes. Here we demonstrate that transgenic mice with activated polyamine catabolism due to overexpression of spermidine/spermine N(1)-acetyltransferase (SSAT) had reduced white adipose tissue (WAT) mass, high basal metabolic rate, improved glucose tolerance, high insulin sensitivity, and enhanced expression of the OXPHOS genes, coordinated by increased levels of PGC-1 alpha and 5'-AMP-activated protein kinase (AMPK) in WAT. As accelerated polyamine flux caused by SSAT overexpression depleted the ATP pool in adipocytes of SSAT mice and N(1),N(11)-diethylnorspermine-treated wild-type fetal fibroblasts, we propose that low ATP levels lead to the induction of AMPK, which in turn activates PGC-1 alpha in WAT of SSAT mice. Our hypothesis is supported by the finding that the phenotype of SSAT mice was reversed when the accelerated polyamine flux was reduced by the inhibition of polyamine biosynthesis in WAT. The involvement of polyamine catabolism in the regulation of energy and glucose metabolism may offer a novel target for drug development for obesity and type 2 diabetes.

Sentinel node and vulvar cancer: a series of 47 patients.

BACKGROUND: There is growing interest to apply the sentinel node technique in the treatment of vulvar cancer. METHODS: All charts of the patients operated on for vulvar cancer at Tampere University Hospital from January 1, 2001 through June 30, 2005 were retrospectively reviewed. Demographic, clinical, and histopathological information was collected from each patient. The sentinel lymph node mapping was done intraoperatively either with a combination of the radioisotope and dye techniques (40 patients) or with the dye technique alone (7 patients). The sentinel lymph node was dissected separately for histopathological evaluation, and then a routine inguinal lymphadenectomy was performed. RESULTS: The final FIGO surgical Stage distribution was: Stage I, 11 (23%); Stage II, 14 (30%); Stage III, 21 (45%); and Stage IV, 1 (2%). Sentinel lymph node was identified in 46 (98%) women with either one or both of the methods. In Stage I-II, the sentinel lymph node identification rate was 25/25 (100%) with the combined method. The only patient with unidentified sentinel lymph node had lymphatic spread beyond inguinal area or Stage IV disease. Eighteen of the sentinel lymph nodes (39%) were positive for tumor cells, and in 5 cases additional metastatic nodes were found. One patient with macroscopically enlarged metastatic inguinal nodes and Stage III disease had a negative sentinel lymph node. In the 25 patients with Stage I-II disease, the false-negative rate of the sentinel lymph node method was 0/4, giving a negative predictive value of 1.00. CONCLUSIONS: A sentinel node identification rate of 98% with a false-negative rate of 0% in the patients with Stage I-II disease is an encouraging finding.

Drug-eluting biodegradable poly-D/L-lactic acid vascular stents: an experimental pilot study.

PURPOSE: To evaluate in vivo a new drug-eluting biodegradable vascular stent with respect to biocompatibility, neointimal hyperplasia formation, and reliability. METHODS: Self-expanding biodegradable poly-96L/4D-lactic acid (PLA) stents with 2 drugs (PLA + dexamethasone [DEX] and PLA + simvastatin [SIM]) and 2 different coatings (PLA + P(D,L)LA and PLA + polycaprolactone [PCL]) were compared with a self-expanding stainless steel Wallstent. The stents were implanted in both common iliac arteries of 8 pigs. Prior to sacrifice at 1 month, angiography was performed to determine patency. Specimens were harvested for quantitative histomorphometry; vascular injury and inflammation scores were assigned to the stented iliac segments. RESULTS: All stented arteries were angiographically patent. The mean luminal diameter (3.05 mm) and area (30.36 mm2) of DEX-eluting PLA stents were decreased compared to other stents (PLA + P(D,L)LA: 3.66 mm and 43.92 mm2; PLA + SIM: 4.21 mm and 56.48 mm2; PLA + PCL: 4.19 mm and 54.64 mm2; Wallstent: 5.01 mm and 81.19 mm2). Wallstents and DEX-eluting PLA stents induced minimal intimal hyperplasia: PLA + DEX: 0.16 mm, PLA + P(D,L)LA: 0.35 mm, PLA + SIM: 0.33 mm, PLA + PCL: 0.29 mm, and Wallstent: 0.18 mm. The vascular injury scores demonstrated only mild vascular trauma for all stents. Only mild to moderate inflammatory reaction was noted around stent struts with a vascular inflammation score. CONCLUSIONS: Biodegradable polymer stents appear to be biocompatible and reliable, causing minimal neointimal hyperplasia. Furthermore, the new biodegradable poly-D/L-lactic acid stent can be used as a local drug delivery vehicle. The DEX-eluting PLA stent reduces neointimal hyperplasia. The findings show a need for further investigation to prove the efficacy and safety of this new biodegradable drug-eluting stent.