Comparison of the biomechanical effect of posterior condylar offset and kinematics between posterior cruciate-retaining and posterior-stabilized total knee arthroplasty

Background

The effect of the changes in the femoral posterior condylar offset (PCO) on anterior–posterior (AP) translation and internal–external (IE) rotation in cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) remains unknown. The purpose of this study was to compare the kinematics in CR and PS TKA with respect to the difference in prosthetic design and PCO change through a computational simulation.

Primary malignant melanoma of the cervical spinal nerve root

The authors report on a case of primary malignant melanoma of the 7th cervical spinal nerve root in a 45-year-old woman. Neuro-radiological features of this extra-dural mass were suggestive of a nerve sheath tumor. The lesion underwent total gross resection through the anterolateral approach. The patient's postoperative course was uneventful. Histopathological investigation confirmed malignant melanoma. There was no evidence of tumor recurrence or other melanotic lesions on regular follow-up examinations until the postoperative eighth month. When treating a common, benign-looking lesion of the cervical spinal nerve root, surgeons should be aware of the potential to encounter such a malignant tumor.     

Two cases of chronic pancreatitis with pseudocyst complicated by obstructive jaundice

We recently treated two cases of chronic pancreatitis with obstructive jaundice due to compression of the common bile duct by pancreatic pseudocyst. The two cases were males admitted with the complaint of icteric skin color. The first, a 46-year-old male, admitted with the complaint of icteric skin color. He was treated by operative cystojejunostomy after percutaneous drainage of the pseudocyst and percutaneous transhepatic biliary drainage. The other case was a 58 year-old male who admitted with the complaint of icteric skin color. He had an infected pseudocyst in the pancreas and was endoscopically treated. Both of them were discharged with favorable clinical course and normal laboratory findings after the treatment. The former patient remained well 11 months after treatment, but the latter patient died from necrotizing pancreatitis and septic shock 6 months after treatment. Most cases of obstructive jaundice associated with pseudocysts appear to be due to fibrotic stricture of the intrapancreatic portion of the common bile duct rather than due to compression of the bile duct by the pseudocyst. In a patient with secondary pancreatic infection or obstructive jaundice following pancreatic disease, differentiating between these two conditions is an important aspect of accurate diagnosis and therapy. Herein we report two unusual cases of chronic pancreatitis with pseudocyst complicated by obstructive jaundice.     

Biological Activity of a Mouse-Human Chimeric Immunoglobulin G2 Antibody to Cryptococcus neoformans Polysaccharide

The variable regions of the heavy and light chains of the protective murine monoclonal antibody (MAb) 2H1 (m2H1) were expressed with the human constant region genes for immunoglobulin G2 (IgG2) and kappa, respectively, to construct a chimeric antibody (ch2H1). ch2H1 retains the specificity of the parent MAb, exhibits biological activity, and lacks the toxicity of the parent murine IgG1 in chronically infected mice.     

Malignant rhabdoid tumor of the kidney--a case report.

Malignant rhabdoid tumor is a distinct renal tumor in children. It had been regarded as a rhabdomyosarcomatoid variant of Wilms' tumor, but it is now thought as a separate entity. We report a case of malignant rhabdoid tumor of the kidney in a 26-month-old girl who presented with a left abdominal mass. Grossly, a large mass in the lower pole of the left kidney was well encapsulated and measured 4 x 4 x 3.5cm. On cross section, it was soft and yellowish white and showed multifocal necroses. The mass was mainly located in the medial medullary portion and compressed the renal pelvis laterally. Microscopically, the tumor masses were hypercellular and anaplastic without definite blastematous elements. In larger portion, the tumor cells had abundant eosinophilic cytoplasm and hyaline globules. In addition to the classic "rhabdoid" feature, alveolar, sclerosing, and lymphomatous patterns were seen. Ultrastructurally, tumor cells with abundant cytoplasm contained tangles of intermediate filament corresponding to vimentin in immunostaining.     

Mechano-active scaffold design of small-diameter artificial graft made of electrospun segmented polyurethane fabrics

To fabricate a "mechano-active" tubular scaffold of nonwoven mesh-type small-diameter artificial graft made of the synthetic durable elastomer, segmented polyurethane, the fabrication technique of electrospinning on a mandrel under a high rotation speed and transverse movement was used. Emphasis was placed on how the rotation speed of the mandrel and the fusion or welding states of fibers at contact points affect the compliance (ease of intraluminal pressure-dependent circumferential inflation) and Young's modulus determined by uniaxial stretching in the longitudinal and circumferential directions. The results showed that a high rotation speed is attributed to exhibit isotropic mechanical properties in the entire range of applied strain but reduces the compliance, and a high fusion state, which is produced using a mixed solvent with a high content of high-boiling-point solvent, reduces the compliance but is expected to exhibit high durability in a continuously loaded pulsatile stress field in an arterial circulatory system.     

Inhibition of interleukin-8 expression by dexamethasone in human cultured airway epithelial cells.

Interleukin-8 (IL-8) is a neutrophil chemotactic factor expressed in many cell types, including human airway epithelial cells (HAEC). Inhaled corticosteroids are now used increasingly early in the treatment of airway inflammation such as in asthma, and directly interact with HAEC at relatively high concentrations. We have investigated the effect of dexamethasone on IL-8 expression in primary cultured HAEC obtained from transplantation donors. Northern blot analysis was used to measure IL-8 mRNA levels in HAEC, and radioimmunoassay was used to measure IL-8 protein in culture supernatant fluids. We demonstrated that IL-8 was expressed by primary cultured HAEC and that this was enhanced by IL-1 beta and tumour necrosis factor-alpha stimulation, but not by IL-6 or lipopolysaccharide. Dexamethasone suppressed IL-8 mRNA expression and protein synthesis dose-dependently in both resting and stimulated HAEC. The half-life of IL-8 mRNA determined in the presence of actinomycin D was less than 1 hr, and dexamethasone preincubation had no effect on mRNA stability. These results support the view that HAEC may play an important role in the pathogenesis of airway inflammatory diseases, and that glucocorticosteroids may exert their anti-inflammatory effects by blocking IL-8 gene expression and generation in these cells.     

Clonorchis sinensis: molecular cloning and localization of myosin regulatory light chain

One cDNA clone was purified from an adult Clonorchis sinensis cDNA library, and its deduced polypeptide sequence was found to be homologous with myosin regulatory light chain (MRLC) of invertebrates and vertebrates. Two amino-acid residues, Thr and Ser, were conserved at the phosphorylation sites that regulate the function of MRLCs. Recombinant C. sinensis MRLC (rCsMRLC) protein was produced and purified from Escherichia coli, and mouse anti-CsMRLC immune sera recognized a protein of molecular weight 24 kDa from a soluble protein preparation of C. sinensis. The CsMRLC protein was immunohistochemically localized to the muscle fibers of the subtegumental muscle layer and to the muscles of oral and ventral suckers. However, the rCsMRLC protein proved to be less useful antigen for the serodiagnosis of human clonorchiasis.The nucleotide sequence reported herein was submitted to GenBank and assigned accession number AY519356.     

Two closely related ubiquitin C-terminal hydrolase isozymes function as reciprocal modulators of germ cell apoptosis in cryptorchid testis

The experimentally induced cryptorchid mouse model is useful for elucidating the in vivo molecular mechanism of germ cell apoptosis. Apoptosis, in general, is thought to be partly regulated by the ubiquitin-proteasome system. Here, we analyzed the function of two closely related members of the ubiquitin C-terminal hydrolase (UCH) family in testicular germ cell apoptosis experimentally induced by cryptorchidism. The two enzymes, UCH-L1 and UCH-L3, deubiquitinate ubiquitin-protein conjugates and control the cellular balance of ubiquitin. The testes of gracile axonal dystrophy (gad) mice, which lack UCH-L1, were resistant to cryptorchid stress-related injury and had reduced ubiquitin levels. The level of both anti-apoptotic (Bcl-2 family and XIAP) and prosurvival (pCREB and BDNF) proteins was significantly higher in gad mice after cryptorchid stress. In contrast, Uchl3 knockout mice showed profound testicular atrophy and apoptotic germ cell loss after cryptorchid injury. Ubiquitin level was not significantly different between wild-type and Uchl3 knockout mice, whereas the levels of Nedd8 and the apoptotic proteins p53, Bax, and caspase3 were elevated in Uchl3 knockout mice. These results demonstrate that UCH-L1 and UCH-L3 function differentially to regulate the cellular levels of anti-apoptotic, prosurvival, and apoptotic proteins during testicular germ cell apoptosis.     

Role of the Nfa1 Protein in Pathogenic Naegleria fowleri Cocultured with CHO Target Cells

Naegleria fowleri, a free-living amoeba, exists as a virulent pathogen which causes fatal primary amoebic meningoencephalitis in experimental animals and humans. Using infected and immune mouse sera, we previously cloned an nfa1 gene from a cDNA library of N. fowleri by immunoscreening. The nfa1 gene (360 bp) produced a recombinant 13.1-kDa protein, and the Nfa1 protein showed pseudopodium-specific immunolocalization on a trophozoite of N. fowleri. In this study, the role of the Nfa1 protein as a cell contact mechanism of N. fowleri cocultured with target cells was observed by an immunofluorescence assay with an anti-Nfa1 polyclonal antibody. Using confocal microscopic findings, the Nfa1 protein was located on the pseudopodia of N. fowleri trophozoites. The Nfa1 protein in N. fowleri trophozoites cocultured with CHO target cells was also located on pseudopodia, as well as in a food cup formed as a phagocytic structure in close contact with target cells. The amount of nfa1 mRNA of N. fowleri was strongly increased 6 h after coculture.