Medial meniscal root tears and meniscal extrusion transverse length ratios on MRI

Objective

To evaluate the clinical utility of the meniscal extrusion transverse ratio of the medial meniscus in the diagnosis of meniscal root tear compared with the gold standard of arthroscopic diagnosis.

Methods

This retrospective study sample included 32 males and 35 females who underwent MRI at our institution. There were 24 meniscal root tear cases. The control groups were 18 cases of medial meniscal tears without root tears and 25 cases of negative meniscal findings on arthroscopy. Meniscal extrusion (L) and maximal transverse lengths (T) of the medial meniscus were measured, and L/T ratios were calculated. These results were correlated with arthroscopic findings and analysed statistically. With arthroscopic findings used as the standard of reference, the sensitivity and specificity of 10%, 11% and 12% extrusion thresholds, and 3 mm of medial meniscal extrusion (MME) as diagnostic thresholds, were calculated.

Results

The mean length of the meniscal extrusions of meniscal root tears was twice as long as the control group. The mean L/T ratio of the meniscal root tears was approximately 13%, while those of the control groups were 5%. The differences in the L and L/T between the meniscal root tears and normal and meniscal root tears and other meniscal tears were statistically significant (p<0.001), but those between normal and other meniscal tears were not. The best diagnostic discrimination was achieved using an extrusion ratio threshold of 10% (79% sensitivity, 86% specificity). The 3 mm of MME threshold demonstrated high specificity (98%), but not high sensitivity (54%).

Conclusion

The mean L/T ratio of the meniscal root tears was approximately 13% and was statistically significant. The best diagnostic discrimination was achieved using an extrusion ratio threshold of 10%.

Advances in knowledge

The use of the L/T ratio in combination with MME can be a useful method for evaluating medial meniscal root tears.The meniscal roots are the sites where the knee meniscus attaches to the central tibial plateau [1]. In many cases, a meniscal root tear is not prominent on a single MRI image as the structures follow oblique courses. Medial meniscal extrusion (MME) is a significant medial displacement of the medial meniscus with respect to the central margin of the medial tibial plateau and is closely associated with medial meniscal root tears (MMR) [2]. The meniscus is considered “extruded” when it extends beyond the tibial margin; this results from disruption of collagen fibres within the meniscus that provide hoop strength [3]. The critical length of extrusion is approximately 3 mm [4-5]. There is some uncertainty regarding the length of the extrusion because the transverse diameter of the medial meniscus varies with age and individual; uniform length criteria can be replaced with length ratios. The current study was performed to evaluate the clinical utility of the meniscal extrusion transverse ratio of the medial meniscus in the diagnosis of the meniscal root tears as compared with the gold standard of arthroscopic diagnosis.     

Clock-hour laminar displacement and age in primary open-angle glaucoma and normal tension glaucoma

Background: To find out the relationship between laminar displacement and age between patients with primary open‐angle glaucoma and normal tension glaucoma. Design: Retrospective study conducted at a tertiary university hospital Participants or Samples: Twenty‐six eyes of 26 primary open‐angle glaucoma patients and 52 eyes of 52 normal tension glaucoma patients. Methods: Patients were scanned with a Stratus optical coherence tomography apparatus to measure the retinal nerve fibre layer thickness and to visualize the cross‐sectional laminar displacement of 12 clock‐hour segments, 30 degrees each. Depth1 was defined as the longest distance between the retinal pigment epithelium and the anterior laminar cribrosa surface, which represents the amount of laminar displacement. Main Outcome Measure: Partial correlation coefficients adjusted by mean deviation and intraocular pressure between (i) retinal nerve fibre layer thickness and age, and (ii) Depth1 and age. Results: In the primary open‐angle glaucoma group, strong negative correlations (approximately ?0.343 ～ ?0.738) were found between Depth1 and age. Eight of 12 clock‐hour segments' correlations were significant after Bonferroni correction (α = 0.0021; 24 comparisons). However, no significant correlations were found between Depth1 and age in the normal tension glaucoma group. When the correlation coefficients were compared between the two groups, eight clock‐hour segments showed significant differences after Bonferroni correction. Conclusions: The significantly different correlation between laminar displacement and age between primary open‐angle glaucoma and normal tension glaucoma patients may suggest a different role of the lamina cribrosa to the disease.     

Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy

There has been a tremendous amount of research in the past decade to optimize the mechanical properties and degradation behavior of the biodegradable Mg alloy for orthopedic implant. Despite the feasibility of degrading implant, the lack of fundamental understanding about biocompatibility and underlying bone formation mechanism is currently limiting the use in clinical applications. Herein, we report the result of long-term clinical study and systematic investigation of bone formation mechanism of the biodegradable Mg-5wt%Ca-1wt%Zn alloy implant through simultaneous observation of changes in element composition and crystallinity within degrading interface at hierarchical levels. Controlled degradation of Mg-5wt%Ca-1wt%Zn alloy results in the formation of biomimicking calcification matrix at the degrading interface to initiate the bone formation process. This process facilitates early bone healing and allows the complete replacement of biodegradable Mg implant by the new bone within 1 y of implantation, as demonstrated in 53 cases of successful long-term clinical study.The century-old concept of the fixation device that holds the fractured bones in place to allow repair through the natural bone remodeling process is still being practiced today without alteration (1–5). The recent rapid growth of the elderly demographic of physically active adults has tremendously intensified the occurrence of bone trauma cases, highlighting once again the major drawbacks of current surgical approaches and osteosynthesis systems, such as inevitable secondary surgery to remove the inert fixation devices after complete bone healing and inflammatory response due to the release of metal ions. In the past decade, countless studies have been performed to control and optimize the mechanical and corrosion properties of magnesium-based alloys (6–9), which, thanks to their degradation in the physiological environment, could overcome the limitations of inert implant materials and shift the paradigm of conventional bone fixation devices toward new horizons. Driven by these new possibilities, important findings regarding, among others, the degradation mechanism of Mg-based alloys (10, 11), the formation of corrosion protective layers by degradation products (12, 13), and the osteogenetic properties of Mg ions (14, 15) have been reported in the literature. However, such findings are based on the observation of degradation products and of bone healing at the macroscale level. Due to lack of fundamental understanding on biocompatibility and underlying bone formation mechanism of the degradation product, there is so far only one known case of statistically insignificant clinical study result (16) with a short-term follow-up. In our previous study, we reported successful development and long-term in vivo study of uniformly slowly degrading Mg-5wt%Ca-1wt%Zn alloy system (SI Appendix, Figs. S1 and S2) featuring adequate mechanical strength [ultimate tensile strength (UTS) ∼250 MPa] (17) and containing Ca, known to stimulate the formation of bone, and Zn, known to influence the remodeling of bone (18).Herein, results from open-label interventional long-term clinical study of biodegradable Mg-5wt%Ca-1wt%Zn alloy screws for hand and wrist fractures are reported to demonstrate the clinical efficacy, safety, and feasibility. Furthermore, to identify the fundamental mechanisms by which Mg-5wt%Ca-1wt%Zn alloys promote new bone formation at multiscale levels of the same region, we combined Villanueva staining technique with nano-analytical imaging methods based on SEM and transmission electron microscopy (TEM). Particularly, cover glass-free tissue slides were prepared to permit the observation of exactly the same region from macro- to micro- to nanoscale using three different analytical microscopes allowing the complete and thorough analysis of the Mg alloy–bone interface from a metallographic perspective. Such an approach allowed, to our knowledge for the first time, to systematically investigate the bone formation and to monitor the changes occurring at of the interface between Mg alloy and bone by analyzing element composition and crystallinity using histology, TEM, and SEM.     

HLA typing in chronic type B, D and C hepatitis

Aims: We aimed to test the hypothesis that susceptibility to chronic HBV, HDV or HCV infections or their pathology is influenced by host genetic factors.Methods: The Human Leukocyte Antigens (HLA) (A, B, DR and DQ) were determined by microlym- phocytotoxicity assay in patients with chronic C (n=117), B (n=97) or D (n=27) hepatitis and their frequencies were compared with those of 489 healthy controls.Results: No statistically significant association was found between any HLA antigen and chronic B or D hepatitis. A significantly higher frequency of HLA-B14 was observed in patients with chronic persistent or active C hepatitis (16.7% of 90 versus 5.9% of 489, χ²=10.9, pc<0.05, Relative Risk=3.17, Etiological Fraction=0.11). The frequency of HLA-DR5 was lower in HCV positive patients (24.8%) than in controls (45%, χ²=15.1, pc<0.005, RR=0.4, EF=−0.37).Conclusions: No correlation could be observed between clearance of HBV or HDV and HLA phenotype. Immunogenetic factors may have a role in determining susceptibility to chronic HCV hepatitis, and in Italian patients HLA-DR5 is a protective factor.     

Efficacy and safety of targeted focal ablation versus PV isolation assisted by magnetic electroanatomic mapping

INTRODUCTION: Pulmonary vein (PV) triggers initiate atrial fibrillation (AF). The aim of this study was to compare the outcome of focal PV ablation versus targeted PV electrical isolation aided by multipolar catheter recordings in the coronary sinus (CS) and right atrium and magnetic electroanatomic mapping (MEAM) for drug-refractory AF. METHODS AND RESULTS: Multipolar recordings identified PVs with triggers based on PV ostial pace map match for spontaneous and provoked triggers. PV triggers were provoked by isoproterenol, adenosine, and AF induction followed by cardioversion. MEAM defined PV ostial anatomy and assisted in localization of AF trigger and ablation lesions. All focal PV ablation procedures preceded PV isolation procedures at our institution. To limit a learning curve effect and validate the comparison, the results included outcome of procedures by a single experienced operator in the last 32 consecutive patients undergoing focal PV ablation and in 75 consecutive patients undergoing PV isolation. Patient characteristics were similar with respect to mean age (50 vs 52 years), mean left atrial size (4.3 vs 4.2 cm), presence of paroxysmal AF (84% vs 88%), and demonstration of non-PV triggers (16% in both groups). PV isolation was confirmed in 99% of PVs by multipolar circular catheter. MEAM confirmed noncircumferential ostial ablation in 69% of PVs. Patients undergoing PV isolation had less AF from PV triggers at the end of ablation (1% vs 16%, P < 0.01); had less AF at 2 months (17% vs 42%, P < 0.001); and had 1-year freedom from AF of 80% versus 45% (P < 0.001). Adverse events were low in both groups with no stroke or symptomatic PV stenosis. CONCLUSION: Using the described techniques, PV electrical isolation of PVs demonstrating spontaneous and/or provoked triggers is superior to focal PV ablation, with marked differences in outcome by 2 months. MEAM confirmed the noncircumferential nature of ostial ablation for effective isolation of most PVs and may play a role in the low risk and good outcome observed. The good outcome of targeted PV isolation as described suggests the need for a prospective comparison of targeted versus empiric PV isolation techniques.     

Epidemiologic and Phylogenetic Characteristics of Porcine Reproductive and Respiratory Syndrome Viruses in Conventional Swine Farms of Jeju Island as a Candidate Region for PRRSV Eradication

Jeju island is the biggest island in Korea. The imports of pigs or their relatives from mainland Korea to this island has been banned since 1998. With this unique geographical and epidemiological context, epidemiology of porcine reproductive and respiratory syndrome virus (PRRSV) was investigated on the island. While all investigated farms showed 100% of seropositive rate for PRRSV, pigs on 37.2% (16/43) of the farms had viremia with type II PRRSV. The seropositive and viremia‐positive rates for PRRSV in 30‐ to 60‐day‐old pigs were significantly higher in the western area (‘swine farm complex’ area) than the eastern area (‘Scattered swine farm’ area) of Jeju island. When 21 ORF5 sequences obtained from viremic sera were phylogenetically analysed, lineage 5 and Kor (newly termed in this study) of type II PRRSV were only found in Jeju island without changes from a previous report (2002–2003). Because other lineages of type II PRRSV (lineage 1 and 3) and type I PRRSV have recently emerged in mainland Korea, the banning of pigs’ movement might be effective to protect the island from the introduction of these new PRRSV genotypes. Under this epidemiological condition (no introduction of new strains except for the modified‐live vaccine (MLV) strain), the positive selection sites were analysed based on ORF5 of the virus. The amino acid 58 of GP5 (located on the hypervariable region) was predicted as a strong positive selection site. Although 51.2% (22/43) of the investigated farms had applied MLV, field strains of type II PRRSV were still circulating with strong positive selection. However, the restricted population of type II PRRSV (lineage 5 and Kor) without introduction of type I PRRSV or the other lineages of type II PRRSV indicate that the island has an effective quarantine system, which would allow PRRSV eradication.     

Quadruplex amplification of polymorphic STR loci in a Korean population

Multiplex PCR amplification has been useful for gene mapping with polymorphic short tandem repeat (STR) loci. We have tested the four loci D20S470, D13S325, HumFOLP23 and D10S2325 for the simultaneous typing of more than 100 unrelated Koreans. This analysis allows a single base pair resolution and rapid typing with silver staining. The allele and genotype distributions are in accordance with Hardy – Weinberg expectations. These STR loci have proven useful for forensic analysis and paternity tests in which the variable number of tandem repeat (VNTR) loci have some limitations. Received: 25 November 1997 / Received in revised form: 25 February 1998     

Differential in vivo cytokine mRNA expression in lesional skin of intrinsic vs. extrinsic atopic dermatitis patients using semiquantitative RT-PCR

BACKGROUND: A small subgroup of atopic dermatitis (AD) patients with normal serum IgE levels and without specific IgE sensitization has been termed 'intrinsic type of AD' (ADi) as a counterpart to the term 'extrinsic type of AD' (ADe). However, there are neither molecular markers nor clinically diagnostic tools for distinguishing between ADi and ADe. OBJECTIVE: The present studies were undertaken to clarify the pathogenesis and in vivo cytokine micromilieu of ADi patients in comparison with ADe patients. METHODS: We used semiquantitative RT-PCR to investigate the expression of various cytokines and assessed the tissue eosinophil counts in skin biopsies from both types of AD patients. RESULTS: Although there was no significant difference of cellular infiltrates in the lesional skin between ADe and ADi patients, ADe had significantly increased tissue eosinophilia than ADi. Based on our RT-PCR, the expression patterns of cytokines could be categorized into four groups. The first group includes IL-5, IL-13, and IL-1beta, whose levels of mRNA expression were higher in both types of AD patients than non-atopic (NA) subjects, while ADe patients had even higher levels than ADi patients. The second group includes interferon-gamma (IFN-gamma), IL-12, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4, and IL-10, whose levels of mRNA expression were elevated in both types of AD patients without differences between ADe and ADi patients. The third group includes tumour necrosis factor-alpha (TNF-alpha), whose mRNA expression was more decreased in both types of AD patients than NA, and the fourth group includes IL-6 and transforming growth factor-beta (TGF-beta), which did not show any differences among the three groups. CONCLUSION: These current data demonstrate that the expressions of cytokines IL-5, IL-13, and IL-1beta mRNA and the number of dermal infiltrating eosinophils are increased in ADe patients compared with ADi patients.