MRI of the medial meniscus in patients over 40 years of age with osteoarthritic knees

MRI was performed for 171 medial menisci of 147 patients, ranging in age from 40 to 86 years (mean 66.6 years), who showed clinical signs in the medial compartment. We classified the MRI findings of the medial menisci using the modified grading system of Crues et al. (Radiology 1987;164:445–448) [1], and their grade 3B into three types based on the shape of the meniscus at the menisco-capsular junction as follows; a blunted change with intrameniscal signal as type 1, flattened and/or herniated as type 2, and a diffuse swelling on the joint surface sometimes obscure as if shredded as type 3. Their mean age was lower in grades 1 and 3A, and higher in grades 2 and 3B. Their mean clinical evaluation score according to the Japanese Orthopaedic Association was higher in grades 1 and 3A, and lower in grades 2 and 3B. In grade 3B, type 1 showed similar MRI findings and had similar patient background to those in grade 2. The MRI of the medial menisci in the osteoarthritic knee of those aged 40 years or more showed characteristic shapes, especially at the menisco-capsular junction, that were correlated to patient age and to the clinical severity of the osteoarthritis. We concluded that the MRI findings of the medial meniscus were usefully divided into six groups: groups 1–3 with clear edges and groups 4–6 with diffuse edges.     

Analysis of texture in macroradiographs of osteoarthritic knees using the fractal signature

Texture of regions of macroradiographs (x5) of six normal and five osteoarthritic knee joints, taken on a high resolution microfocal x-ray unit, are examined using mathematical morphology. Radiographs of bones are two-dimensional projections of attenuation coefficient through the three-dimensional (3D) joint structure. Visible texture represents the summation of the attenuation from numerous thin plates of bone. Where there is no organization in the trabeculae, resultant radiographs approximate a fractal surface. Varying structuring element size in mathematical morphology allows estimation of fractal dimension over a range of resolution. Variation of fractal dimension with resolution, the fractal signature, indicates how images deviate from fractal surfaces. By correct choice of structuring element, a texture analysis method using the fractal signature has been developed, tolerant to changes in image acquisition and digitization. Texture in regions of radiographs of normal tibia approximates a fractal surface with dimension 2.8 as does vertical structure in arthritic patients. In osteoarthritic knee joints, horizontal tibial trabeculae thicken. Horizontal structure in the tibia on radiographs of arthritic patients deviates from the fractal model. This is indicated by peaks in the fractal signature whose height and position match a visual assessment of the degree of arthritic change.     

Maturation of tissue engineered cartilage implanted in injured and osteoarthritic human knees

The regeneration of damaged organs requires that engineered tissues mature when implanted at sites of injury or disease. We have used new analytic techniques to determine the extent of tissue regeneration after treatment of knee injury patients with a novel cartilage tissue engineering therapy and the effect of pre-existing osteoarthritis on the regeneration process. We treated 23 patients, with a mean age of 35.6 years, presenting with knee articular cartilage defects 1.5 cm2 to 11.25 cm2 (mean, 5.0 cm2) in area. Nine of the patients had X-ray evidence of osteoarthritis. Chondrocytes were isolated from healthy cartilage removed at arthroscopy. The cells were cultured for 14 days, seeded onto esterified hyaluronic acid scaffolds (Hyalograft C), and grown for a further 14 days before implantation. A second-look biopsy was taken from each patient after 6 to 30 months (mean, 16 months). After standard histological analysis, uncut tissue was further analyzed using a newly developed biochemical protocol involving digestion with trypsin and specific, quantitative assays for type II collagen, type I collagen, and proteoglycan, as well as mature and immature collagen crosslinks. Cartilage regeneration was observed as early as 11 months after implantation and in 10 out of 23 patients. Tissue regeneration was found even when implants were placed in joints that had already progressed to osteoarthrosis. Cartilage injuries can be effectively repaired using tissue engineering, and osteoarthritis does not inhibit the regeneration process.     

Metabolic correlates to pacemaker activity in the smooth muscle of guinea-pig mesotubarium

Oxygen consumption (FO2) and lactate production (Flac) were measured during spontaneous activity in the guinea-pig mesotubarium. During spontaneous contractions FO2 increased to maximally 0.270 +/- 0.025 mumol min-1g-1 (n = 23), followed by a rapid fall immediately upon relaxation. In the relaxed period (5-15 min) between spontaneous contractions FO2 continued to slowly decrease by about 25% towards a final value of 0.150 +/- 0.01 mumol min-1g-1. Flac showed no consistent variation during the relaxed period. Ouabain (10(-6)M) produced a contracture, which was abolished by the Ca2(+)-antagonist felodipine (10(-6)M). In the presence of felodipine, addition of ouabain caused depolarization and a decrease of oxygen consumption by 21% and of lactate production by 31%. Exchange of glucose in the physiological Krebs solution for beta-hydroxybutyrate did not influence spontaneous activity, while subsequent addition of cyanide (2 mM) abolished contractions and caused a hyperpolarization of 15 mV. Blockade of ATP-dependent K+ channels by addition of glibenclamide (10(-7)M) to the relaxed muscle in this situation caused spontaneous contractile activity to reappear. In glucose-containing Krebs solution glibenclamide had no effect on the spontaneous contractile and electrical activity and contractions persisted after addition of cyanide. The relaxing and hyperpolarizing effect of pinacidil could be counteracted by addition of glibenclamide. The results suggest that a decrease in electrogenic Na+/K(+)-pump activity in the course of the relaxed period between contractions could contribute to the pacemaker behaviour. ATP-dependent K+ channels, while having little influence on the spontaneous contractile activity under normal metabolic conditions, could be activated during blockade of aerobic and anaerobic metabolism, leading to inhibition of pacemaker activity.     

Cartilage repair examined by second-look arthroscopy following double-level osteotomy performed for osteoarthritic knees with severe varus deformity

BackgroundThe purpose of this study was to examine the status of cartilage repair by second-look arthroscopy following double-level osteotomy (DLO) performed for osteoarthritic knees with severe varus deformity.MethodsForty-seven consecutive knees in 33 patients who underwent DLO were included in the study. The surgical technique used was a minimally invasive DLO procedure combining lateral closed-wedge distal femoral and medial open-wedge high tibial osteotomies. In the second-look arthroscopic evaluation, the following grading system proposed by Koshino was adopted: Stage A, no repair; stage B, pink fibrous tissue with or without partial coverage with white fibrocartilage; and stage C, total coverage with cartilage. The findings corresponding to stage B or C were considered as repaired. Arthroscopic assessment was performed for each compartment. Clinical outcomes were evaluated using the validated outcome measures.ResultsThe mean age at surgery was 62.8 ± 6.2 years (range: 45–75 years), and the mean time period from DLO to second-look arthroscopy was 17.1 ± 5.0 months (range: 12–33 months). Cartilage repair to some extent was identified in over 90% of the medial femoral and tibial condyles, and 12.8% of the patellar facet. As for clinical scores, both Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee Subjective Knee Form (IKDC) subjective scores significantly improved after surgery (P < 0.01).ConclusionsEvaluation of the present study subjects showed that DLO could induce cartilage repair in the majority of the affected femoral and tibial articular surfaces with significant clinical improvement. In the patellar facet, however, cartilage repair could be identified in only 12.8% of cases.     

Inflammatory effect of advanced glycation end products on human meniscal cells from osteoarthritic knees

Objective  

To investigate the inflammatory effects of advanced glycation end-products (AGEs) through the receptor for AGE in meniscal cells from osteoarthritic knees, and examine effects of hyaluronan (HA) on AGE-induced inflammation.     

The repair of osteochondral defects in osteoarthritic rabbit knees by the use of carbon fibre

Implants of carbon fibres and carbon fibre patches were tested for their biocompatibility in osteochondral defects in rabbits with instability induced knee osteoarthrosis. The resulting repairs were compared to control holes in which no implant was inserted. There was no apparent biodegradation when carbon fibre bundles were implanted for periods from 2 to 18 weeks, and the carbon fibre patches appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 26 weeks. Also carbon fibre in the form of a patch promoted the healing of the osteochondral defects in osteoarthritic femora with well organised fibrous tissue over repaired subchondral bone. The use of these carbon-fibre patches is suggested as an implant material for the restoration of articular surfaces in osteoarthritis.     

The three-dimensional quadriceps vector is most parallel to the spherical axis in Japanese varus osteoarthritic knees

BackgroundThe quadriceps femoris may be a reliable reference to proper alignment in total knee arthroplasty (TKA). We previously showed the quadriceps vector (QV) to be the most parallel to the spherical axis (SA-center hip to center medial condyle) for healthy knees. The purpose of this study was to determine whether the QV is the most parallel to the SA in knees with varus osteoarthritis (OA).MethodsCT imaging for 35 varus OA and 40 healthy Japanese knees was used to construct 3D models of the femur, patella and each quadriceps component for each subject. The QV was calculated using principal component analysis for direction and was compared with the relationship of the QV to the measurement axes of the lower extremity, including the anatomical, mechanical and spherical axes.ResultsThe direction of the QV for the OA knee group was different from that for the healthy knee group in 3D space (medio-lateral direction: women, p = 0.532, men, p = 0.540; antero-posterior direction: women, p = 0.141, men, p < 0.001). However, the angle of the QV in relation to measurement axes in the coronal plane was closest to the SA in both groups (around 1°), with no difference between the groups (women, p = 0.382, men, p = 0.943).ConclusionIn the coronal plane, the SA most closely approximates the QV for both healthy and OA knees. The more posterior QV position in the 3D space may affect the patellofemoral joint.     

Beta-hemolytic activity of Trichomonas vaginalis correlates with virulence

The reasons that some women develop symptomatic trichomonal vaginitis, whereas many other infected women remain asymptomatic, are unclear, but it has been suggested that Trichomonas vaginalis strains vary in their intrinsic virulence. We describe beta-hemolytic activity in T. vaginalis which correlates with virulence in patients as well as in an animal model and in tissue culture. Fresh T. vaginalis isolates from four women with severe, symptomatic trichomoniasis had high-level (86.3 +/- 6.6%) hemolytic activity, whereas isolates from three completely asymptomatic women had low-level (45.3 +/- 8.4%) hemolytic activity (P less than 0.001). Hemolytic activity also correlated with the production of subcutaneous abscesses in mice (r = 0.74) and with destruction of CHO cell monolayers (r = 0.94). All of the 20 clinical isolates of T. vaginalis tested possessed hemolytic activity. The beta-hemolysin may be a virulence factor for T. vaginalis.     

Double-level osteotomy for severe varus osteoarthritic knees can prevent change in leg length and restore physiological joint geometry

BackgroundIt is unclear whether double-level osteotomy (DLO) combining closed-wedge osteotomy in the distal femur and open-wedge osteotomy in the proximal tibia deformity can prevent change in leg length and excessive coronal inclination of the tibial articular surface in surgical correction of the severe varus knee. The purpose of this study was to examine the postoperative change in leg length as well as radiological and clinical outcomes following DLO compared with the results obtained from knees undergoing isolated open-wedge high tibial osteotomy (OW-HTO).MethodsIn cases of severe varus knee deformity (hip–knee–ankle angle (HKA) > 10°) 29 patients undergoing DLO and 35 patients undergoing OW-HTO were included. If the predicted mechanical medial proximal tibial angle (mMPTA) was 95° or greater or the wedge size was 15 mm or greater in the surgical simulation, then DLO was considered as the surgical of option. In cases where these criteria were not met, OW-HTO was selected. All patients were followed up for a minimum of 2 years.ResultsThe changes in the length of the whole leg in the DLO and OW-HTO groups averaged 2.3 ± 4.8 mm and 9.3 ± 7.2 mm, respectively (P < 0.001). mMPTA of more than 95° was found in no knee in the DLO group.ConclusionsThis study showed that DLO could avoid leg length change and non-physiologic joint lines when performed in patients with varus HKA > 10°, and the predicted mMPTA was 95° or greater or the wedge size was 15 mm or greater in the surgical simulation.     

BMI、TSH、hs-CRP在妊娠代谢综合征患者中的表达及意义

目的 研究妊娠BMI、TSH、hs-CRP水平与妊娠代谢综合征的相关性.方法 选择2016年1月至2017年1月在我院分娩的109例单胎宫内孕33 ～ 36周的孕妇作为研究对象,其中78例妊娠期高血压(HDCP)患者为A组,31例妊娠期代谢综合征(GMS)患者为B组,同期102例健康产妇为C组.分别观察3组对象的空腹血糖、TSH、hs-CRP、孕前BMI、甘油三酯、总胆固醇、高密度脂蛋白及低密度脂蛋白水平,并研究其与妊娠期代谢综合症的关系.结果 A组、B组、C组的年龄、身高、孕周及产次之间比较差异均不具有统计学意义(P＞0.05).C组的空腹血糖、孕前BMI、hs-CRP水平均显著低于A组、B组,差异具有统计学意义(P＜0.05).TSH水平3组比较无统计学差异.C组的总胆固醇、甘油三酯和低密度脂蛋白明显低于A组、B组,而高密度脂蛋白明显高于A组、B组,差异具有统计学意义(P＜0.05).孕前BMI、hs-CRP均是妊娠代谢综合症的显著危险因素,而TSH与妊娠代谢综合症关系不显著.结论 产妇孕前BMI、hs-CRP过高均是发生妊娠代谢综合征的危险因素,肥胖或者怀孕期间营养过剩容易导致产妇糖脂代谢异常而诱发妊娠代谢综合征.     

Metabolic correlates of clinical heterogeneity in questionable Alzheimer's disease

Thirty-four subjects with questionable Alzheimer's disease (QAD) were included in a 3-year prospective study and underwent neuropsychological testing and measurement of brain metabolism using FDG-PET at entry. Seventeen patients (50%) did not convert to AD during the follow-up period. Compared to elderly controls of similar age, the cerebral activity of non-converters was reduced in the dorsolateral prefrontal cortex. Moreover, the variability of metabolism in the posterior cingulate cortex was related to their visuospatial memory performance, while disparity in parietal activity was related to their verbal memory performance. These results demonstrate the cerebral metabolic heterogeneity of patients with QAD. Initial functional images of converters showed that activity was already impaired in the posterior cingulate, lateral temporal cortex, anterior cingulate and orbitofrontal cortex. This metabolic pattern is consistent with a pre-dementia stage of AD, and highlights the fact that significant frontal metabolic involvement may be associated with impaired activity in posterior associative cortices in very early AD.     

Increased muscle activity to stabilise mobile bearing knees in patients with rheumatoid arthritis

The aim of this study was to assess the differences in muscle activity (surface EMG) between a posterior stabilised (PS) total knee design and a mobile bearing (MB) posterior cruciate ligament retaining design in rheumatoid arthritis (RA) patients during a step-up task. Four patients with a PS total knee prosthesis and three patients with a MB total knee prosthesis were selected based on pain score, knee function, range of motion and joint stability. Clinical scores and functional scores were comparable between the two groups pre-operatively and at the 1-year follow-up. Visual analysis of the EMG activity of the main flexor and extensor muscles showed that the activity of both extensor and flexor muscles of the MB group was on average higher compared to the PS group. When the maximum activities of the muscles were compared, the patients in the MB group showed a significant higher maximum peak activity (p<0.05) of the Vastus Medialis (VM), Vastus Lateralis (VL) and Semitendinosus (ST) during step-up than the patients in the PS group. Also the instance of activation of the Vastus Medialis and the Vastus Lateralis was significant earlier in the MB group compared to the PS group. Since the differences between the PS and the MB group did not only show an increase of muscle activity but also an earlier activation of the flexor muscles, this may express compensation by coordination. Rehabilitation programs for RA patients should include besides muscle strength training, elements of muscle-coordination training.     

Human cortical activity correlates with stereoscopic depth perception

Stereoscopic depth perception is based on binocular disparities. Although neurons in primary visual cortex (V1) are selective for binocular disparity, their responses do not explicitly code perceived depth. The stereoscopic pathway must therefore include additional processing beyond V1. We used functional magnetic resonance imaging (fMRI) to examine stereo processing in V1 and other areas of visual cortex. We created stereoscopic stimuli that portrayed two planes of dots in depth, placed symmetrically about the plane of fixation, or else asymmetrically with both planes either nearer or farther than fixation. The interplane disparity was varied parametrically to determine the stereoacuity threshold (the smallest detectable disparity) and the upper depth limit (largest detectable disparity). fMRI was then used to quantify cortical activity across the entire range of detectable interplane disparities. Measured cortical activity covaried with psychophysical measures of stereoscopic depth perception. Activity increased as the interplane disparity increased above the stereoacuity threshold and dropped as interplane disparity approached the upper depth limit. From the fMRI data and an assumption that V1 encodes absolute retinal disparity, we predicted that the mean response of V1 neurons should be a bimodal function of disparity. A post hoc analysis of electrophysiological recordings of single neurons in macaques revealed that, although the average firing rate was a bimodal function of disparity (as predicted), the precise shape of the function cannot fully explain the fMRI data. Although there was widespread activity within the extrastriate cortex (consistent with electrophysiological recordings of single neurons), area V3A showed remarkable sensitivity to stereoscopic stimuli, suggesting that neurons in V3A may play a special role in the stereo pathway.     

Anterior cingulate activity correlates with blood pressure during stress

The anterior cingulate cortex presumptively regulates blood pressure reactions to behavioral stressors. There is little evidence in humans, however, that stressor-evoked changes in blood pressure correlate with concurrent changes in anterior cingulate activity. Using fMRI, we tested whether changes in mean arterial blood pressure correlate with ongoing changes in blood oxygen level dependent (BOLD) activation in 9 women and 11 men who completed a stressful Stroop color-word interference task. Higher mean arterial pressure during the Stroop task correlated with greater BOLD activation in two regions of the cingulate cortex (perigenual and mid-anterior) and in other networked brain regions, including the insula, thalamus, and periaqueductal gray. These results support the hypothesis that the anterior cingulate cortex regulates blood pressure reactions to behavioral stressors in humans.     

Cholinergic activity correlates with reserve proxies in Alzheimer's disease

The clinical expression of Alzheimer's disease (AD) occurs as neuropathology exceeds the brain “reserve capacity.” A possible association between the cholinergic system and reserve is suggested by preclinical observations that the cholinergic system allows cortical plasticity and by clinical observations of variable responses to cholinergic treatments depending on the patient’s educational level. The aim of this study was to investigate the association of reserve proxies, that is, education and occupation, with acetylcholinesterase (AChE) activity, measured voxelwise by [¹¹C]-MP4A and positron emission tomography (PET), in 9 healthy controls (HC), 7 patients with early probable AD, and 9 subjects with mild cognitive impairment (MCI) at the time of PET imaging, who progressed to AD at follow-up (prodromal AD). The analysis of prodromal and early AD showed positive correlations between education and AChE activity in the hippocampus, bilaterally, and between occupation and AChE activity in the right posterior cingulate gyrus. The significant correlation between AChE activity in structures belonging to the memory network and reserve proxies suggests that the brain reserve in AD is associated with a preserved/stimulated cholinergic neurotransmission.     

Graft morphology correlates with fibroblast activity in cardiac allograft rejection

Several extracellular matrix substances, such as hyaluronan and fibronectin, may affect graft viability by their involvement in cell adhesion and in migration. These substances are produced locally in the tissue by fibroblasts. The aim of this study was to investigate the activation state of intragraft fibroblasts under various immunosuppressive treatments and to correlate these with morphological parameters. Syngeneic (n = 5) and allogeneic rat (n = 5-6/group) heterotopic heart transplantations were performed. Allogeneically transplanted animals were immunosuppressed with cyclosporine, mycophenolate mofetil or prednisolone. After 10 days, the transplanted hearts were removed for subsequent isolation of intragraft fibroblasts and for evaluation of graft morphology. The hyaluronan synthesis of graft fibroblasts correlated with the cellular infiltration (p < 0.05) and the interstitial oedema (p < 0.05) of the cardiac grafts. In general, proliferation rate and hyaluronan production were of the same magnitude in fibroblasts from allogeneic hearts under immunosuppression with cyclosporine, mycophenolate mofetil or prednisolone as in fibroblasts from syngeneic grafts. A pool of fibroblasts isolated from cardiac grafts of non-immunosuppressed, allogeneically transplanted rats (n = 4) showed considerably higher levels. We concluded that fibroblast activity correlates to the viability of the tissue rather than to the specific drug used for immunosuppression.