T. K. Liu

Simultaneous bilateral total knee arthroplasty in a single procedure

Summary.Eighty-eight consecutive patients undergoing total knee arthroplasty (TKA) were reviewed retrospectively and divided into two groups. Group 1 (64 patients) had both knees replaced simultaneously by one team in a single procedure while Group II (24 patients) had 2 operations staged about 7 days apart. The blood loss, operative time, knee functional score, period of hospitalisation and complications were documented in order to compare the 2 groups. Performing simultaneous bilateral TKA (Group I) did not increase the incidence of operative or post-operative complications. Equally, the functional score and mean intra- and post-operative blood loss were not influenced. The operative time and duration of hospitalisation were significantly shorter in Group I than in Group II. On the basis of the results of this study, it appears that simultaneous bilateral TKA is beneficial.Résumé.Quatre vingt-huit patients consécutifs opérés de l’arthrose (TKA) ont été revus rétrospectivement. Ils ont été divisés en deux groupes. Le groupe I (64 patientes) ont eu leurs genoux remplacés simultanément par une éuqipe durant une procédure unique. Le groups II (24 patients) a subi deux opérations séparées sur 7 jours durant un séjour à l’hôpital. Il en a résulté qu’opérer simultanément une TKA bilatérale (groupe I) n’a pas entraîne d’incident opératoire, ni aucun accroissement des réactions postopératories. Il n’y a pas eu d’influence sur le résultat fonctionnel, ni aucune perte sanguine durant ou après l’opération. Le temps d’opération et la durée d’hospitalisation ont été beaucoup plus courts dans le groupe I que dans le groups II. En prenant en compte les résultats de cette étude, il apparaît qu’une TKA bilatérale simultanéc n’a pas seulement été bénéfique, mais aussi un choic alternatif pour les patients.

E2A-positive gastric MALT lymphoma has weaker plasmacytoid infiltrates and stronger expression of the memory B-cell-associated miR-223: possible correlation with stage and treatment response

Extranodal marginal-zone lymphoma of mucosa-associated lymphoid tissue of the stomach (gastric MALT lymphoma) is derived from memory B cells of the marginal zone. Normal memory B cells do not express markers of germinal-center B cells, such as E2A (immunoglobulin enhancer-binding factor E12/E47), B-cell chronic lymphocytic leukemia/lymphoma 6 (BCL6), or activation-induced cytidine deaminase (AID). E2A is a transcription factor that induces somatic hypermutations and blocks plasma cell differentiation. In 50 stage-IE/IIE1 gastric MALT lymphomas, we confirmed that all cases were BCL6−/AID−, but a subset (50%, 25/50) was E2A+. As E2A− and E2A+ gastric MALT lymphomas had similar numbers of somatic hypermutations without intraclonal variations, which implied an origin from memory B cells, the expression of E2A was best regarded as a marker of aberrant follicular differentiation. Although the status of somatic hypermutation was not affected by E2A, E2A+ gastric MALT lymphoma showed less plasmacytoid infiltrates and higher expressions of miRNA-223, a microRNA associated with memory B cells. Clinically, E2A+ gastric MALT lymphomas were more likely to spread to perigastric lymph nodes and were less responsive to Helicobacter eradication therapy than were E2A− gastric MALT lymphomas. Taken together, aberrant E2A expression is a diagnostic feature of a subtype of gastric MALT lymphoma with weaker plasmacytoid infiltrates and stronger miR-223 expression. A prospective study would be necessary to verify the association between E2A expression and a poor response to Helicobacter eradication therapy.

Symmetry of Bone Mineral Density at the Proximal Femur with Emphasis on the Effect of Side Dominance

Abstract. The symmetry and effect of side dominance on the bone mineral density (BMD) of proximal femur was evaluated in 266 normal Chinese women with a dual photon absorptiometer (DPA, Norland 2600). The BMDs of the femoral neck, trochanter, and Wards triangle at the proximal femur in the dominant leg (BMDd) were compared with those of the nondominant side (BMDn). The linear regression of BMDd and BMDn of the corresponding regions at the proximal femur showed a good correlation (r = 0.893–0.941, SEE = 0.052–0.062 g/cm2). The paired difference of proximal femoral BMD was −0.002 ± 0.062 g/cm2 for the femoral neck, 0.003 ± 0.054 g/cm2 for the trochanter, and 0.008 ± 0.062 g/cm2 for the Wards triangle. The ratio of asymmetry for femoral neck BMD was mean ± SD =−0.4 ± 7.8%, for trochanter 0.6 ± 8.1%, and for the Wards triangle 1.3 ± 9.7%. Both paired difference and ratio of asymmetry between BMDd and BMDn were approximately normally distributed, with a mean ± 2 SD ranging from −0.126 to 0.122 g/cm2 for paired difference and −16.0% to 15.2% for the ratio of asymmetry in the femoral neck. These data revealed that dominance had little effect on the proximal femur BMDs. However, the wide range of paired difference and ratio of asymmetry of the proximal femur BMD in the normal individuals should be considered in the interpretation of the proximal femoral BMD.n

Periprosthetic bone mineral density of the distal femur after total knee arthroplasty.

SummaryEvaluation of the bone mineral density (BMD) was performed in the distal femur around the femoral component of a total knee prosthesis. A total of 48 females were enrolled for this study, including 14 with osteoarthritis of one knee undergoing total knee arthroplasty (TKA) with an Osteonics prosthesis, 14 with osteoarthritis of one knee undergoing TKA with a Whiteside prosthesis, and 20 age-matched normal controls. The BMDs of both knees were measured before operation, and then at 3, 6 and 12 months after operation. The preliminary results demonstrate a significant progressive decrease of BMD in the distal femur of the operated knees after TKA, whereas the BMD of the non-operated knees remains stable. The ratio of BMD between the operated femur and the non-operated femur began to decrease 6 months after operation, and was most obvious at the end of the first year (ranging from 7% to 27%). Further investigation is essential to determine the clinical significance of this loss of periprosthetic bone.RésuméLétude de la densité minérale osseuse (DMO) du fémur distal porteur dune prothèse totale a été réalisée. Quarante-huit femmes ont fait lobjet de cette étude. 14 dentre-elles présentaient une gonarthrose unilatérale et ont eu une arthroplastie totale avec une prothèse Osteonics; 14 autres, toujours avec une gonarthrose unilatérale ont eu une arthroplastie totale avec une prothèse Whiteside; enfin, 20 patientes, de même tranche dâges sans arthrose du genou ont servi de groupe témoin. La densité minérale des deux genoux fut mesurée avant lopération, puis à 3, 6 et 12 mois après intervention. Les résultats préliminaires montrent une diminution progressive et significative de la densité minérale dans le fémur distal des genoux opérés par arthroplastie totale. La densité des genoux non opérés reste stable. Le rapport des densités entre fémur opéré et fémur non opéré commence à décroitre 6 mois après lopération et est le plus marqué à la fin de la première année (de 7 à 27%). Dautres investigations sont nécessaires pour évaluer la signification clinique de la diminution de densité de los périprothétique.

Epstein-Barr Virus–Encoded miR-BART20-5p Inhibits T-bet Translation with Secondary Suppression of p53 in Invasive Nasal NK/T-Cell Lymphoma

Nasal NK/T-cell lymphoma (NNL) is an Epstein-Barr virus (EBV)-associated lymphoma derived from cytotoxic NK or T cells of the nasal mucosa. NNLs are noninvasive in the earliest stage, and become invasive with disease progression. The EBV encodes at least 44 miRNAs, whose functions in the pathogenesis of NNL are mostly unknown. We evaluated the levels of 39 EBV-encoded miRNAs with quantitative real-time RT-PCR in a series of 20 noninvasive NNLs and 20 invasive NNLs. miR-BART20-5p was associated most strongly with invasion (P ≤ 0.001), and lack of T-bet, the master transcription factor for cytotoxic NK cells. However, we identified T-bet (official symbol, TBX21) transcripts in T-bet-negative NNLs, implying a block in the translation of T-bet by miR-BART20-5p. In co-transfection experiments, miR-BART20-5p inhibited T-bet translation in both non-Hodgkin and Hodgkin lymphoma cell lines. Endogenous mir-BART20-5p also inhibited translation of T-bet in EBV-infected YT lymphoma cells of NK-cell origin. Induction of T-bet in YT cells up-regulated p53, leading to increased sensitivity in response to doxorubicin. Finally, YT cells transplanted into severe combined immunodeficiency mice had an invasive behavior. Taken together, we conclude that EBV-encoded miR-BART20-5p inhibits T-bet translation with secondary suppression of p53 in invasive nasal NK/T-cell lymphoma. An antagomir to miR-BART20-5p might be an effective therapeutic agent through induction of T-bet and p53.

Proximal femoral dimension in elderly Chinese women with hip fractures in Taiwan.

Abstract: To investigate the relationship between proximal femoral geometry and the occurrence of hip fracture, we compared the geometry of contralateral normal hips of 120 elderly Chinese women with hip fractures, including 63 femoral neck fractures (group A) and 57 intertrochanteric fractures (group B) due to minor trauma, with that of 72 normal elderly Chinese women (group C). The mean ages for group A, B and C subjects were 77.3, 79.7 and 72.9 years, respectively. The femoral neck length (NL), neck width (NW), diameter of femoral head, femoral shaft width just below the lesser trochanter, and neck–shaft angle (θ) were measured on the anteroposterior plain pelvic radiographs. The mean ± SD of NL for group A was 50.4 ± 3.3 mm; for group B, 50.6 ± 3.1 mm; and for group C, 48.8 ± 3.6 mm. Statistical analysis by ANOCOVA and regression showed that only NL of women with hip fractures was significantly longer than controls after correction for age, body height and weight (p <0.01). However, the difference in NL between group A and group B was not significant. By linear regression, the probability of fracture increased only with older age (pu2009<0.001), longer NL (p <0.005) and lighter body weight (p <0.05). By logistic regression, each standard deviation increase in NL increased the risk of hip fracture (age-adjusted odds ratio 1.84; 95% CI, 1.11–3.06). The results confirm the relationship between proximal femoral geometry and the occurrence of hip fracture in elderly Chinese women in Taiwan.

Symmetry of bone mineral density in the hips is not affected by age.

SummaryTo assess the symmetry of bone mineral density (BMD) of the hips, we used dual photon absorptiometry (DPA) to asses BMD in 266 normal Chinese women in the bilateral femoral neck, trochanter and Wards triangle regions. Linear regression analysis of the results showed excellent correlation between the hips. The correlation coefficients for the femoral neck, trochanter and Wards triangle regions were 0.899, 0.892 and 0.935 respectively, and the standard errors of the estimate (S.E.E.) were 0.029, 0.027 and 0.022 g cm -2respectively. Pooling the BMD data of corresponding regions (n = 532), the correlation coefficient was 0.813 for femoral neck versus trochanter, 0.889 for femoral neck versus Wards triangle, and 0.833 for trochanter versus Wards triangle. Further analysis showed mean correlation coefficients of 0.854 for elderly subjects (age > 65 years, n = 51) and 0.887 for younger subjects (age < 65 years, n = 215). In conclusion, assessment of left or right hip BMD may be used to represent the BMD of the contralateral hip and can reduce both the cost and radiation exposure during mass screening for osteoporosis.

Differential Effects of Bone Mineral Content and Bone Area on Vertebral Strength in a Swine Model

Abstract. Since the biomechanical competence of a vertebral body may be closely related to the content and distribution of the bone mineral, we have evaluated the effects of projected vertebral bone area (BA) and bone mineral parameters [bone mineral content (BMC) or bone mineral density (BMD)] on their biomechanical competence. We used dual-energy X-ray absorptiometry (DXA) to assess the bone mineral parameters of 36 swine thoracic vertebrae (T1–T12) and 15 lumbar vertebrae (L1–L5) after removal of the posterior elements. The failure load, compressive stress, and the stored strain energy of these vertebral bodies were assessed by a uniaxial compressive test using an MTS 810 testing system. Multiple regression analysis showed a significantly negative effect of BA and significantly positive effect of BMC on the biomechanical competence (compressive stress, r2= 0.67, P < 0.0001; failure load, r2= 0.75, P < 0.0001). However, the stored strain energy was only related to the BMC (r2= 0.35, P < 0.0001). The contributory effects of BMC and BA on the biomechanical competence were not equal. The effects of BMC was larger than BA in determining the failure load and stored strain energy, whereas the reverse was found for the compressive stress. Using the log-transformed parameters as the regressors resulted in similar results. These results suggested the differential effects of BA and BMC in determining the biomechanical competence of vertebral bodies. We recommend the use of both parameters instead of BMD alone for evaluation of the vertebral biomechanical competence.

Morphological Changes Induced by Prostaglandin E in Cultured Rat Osteoblasts

Prostaglandin E (PGE)-induced morphological changes of osteoblasts and its possible mechanisms were investigated in cultured calvaria and isolated osteoblasts from long bone fragments of neonatal rats. The control osteoblasts, either on the calvaria or isolated from the long bone fragments, were flat, polygonal in shape, and arranged in a monolayer under scanning electron microscopy (SEM) or phase contrast microscopy. Treatment with 1 mumol/L of prostaglandin E2 (PGE2, 2 h) caused these bone cells to contract a soma, whereas 10 and 100 mumol/L PGE2 (2 h) caused 18%-30% of the bone cells to elongate and expose the undersurface. Incubation of the cultured osteoblasts with PGE2 at different time periods showed a bell-shaped pattern with the optimal response at 2 h of incubation. A similar reaction can be induced by treatment with prostaglandin E1 (PGE1) or dibutyryl cyclic adenosine monophosphate (DBcAMP) in combination with 3-isobutyl-1-methylxanthine (IBMX). Furthermore, we assessed the percentage of responsive isolated bone cells to investigate interactions with other agents. The morphological changes induced by PGEs were inhibited by H-8, a protein kinase inhibitor. On the other hand, elevated intracellular calcium enhanced the PGE-induced morphological changes. Fluorescence labeling showed that PGEs caused the breakdown of the actin microfilaments, but spared the microtubules and vimentin filaments in the isolated osteoblast-like cells. These results suggest that the morphological changes of osteoblasts induced by PGEs may be related to the intracellular cAMP and calcium levels.

Expression of CD19 and lack of miR-223 distinguish extramedullary plasmacytoma from multiple myeloma

Yu S‐C, Chen S‐U, Lu W, Liu T‐Y & Lin C‐Wu2028(2011) Histopathology 58, 896–905u2028Expression of CD19 and lack of miR‐223 distinguish extramedullary plasmacytoma from multiple myeloma