In vivo segmental motion of the cervical spine in rheumatoid arthritis patients with atlantoaxial subluxation

OBJECTIVE

The dynamic mechanism underlying cervical spine involvement in rheumatoid arthritis (RA) remains unidentified. The purpose of the current study was to determine the in vivo cervical segmental motion in RA patients with atlantoaxial subluxation (AAS) using a patient-based three-dimensional magnetic resonance imaging (MRI) computer model.

METHODS

Healthy volunteers and RA patients with AAS (all females, n=10) underwent MRI examination of the cervical spine. Each vertebral body from the occipital bone (Oc) to the first thoracic vertebra (T1) was reconstructed from slices of T2-weighted sagittal MR images in the neutral, flexion, and extension positions. Using volume merge methods, each reconstructed vertebral body was virtually rotated and translated. Rotational segmental and translational segmental motions were obtained in three major planes.

RESULTS

Overall, the axial translational motions in the RA group were lower than those in the healthy volunteers; however the axial translational motion at only C1-C2 during flexion was at the same level as that in the healthy volunteers and was greater on the bottom side than that at other intervertebral levels. The frontal rotational motions at C1-C2 during extension were greater in the RA patients than those in the healthy volunteers (p<0.05).

CONCLUSION

The atlantoaxial joints in the RA patients with AAS showed great frontal rotational motion during extension and great axial translation on the bottom side during flexion. The current noninvasive MRI-based method could be useful in evaluating the 3-D dynamic mechanism underlying cervical involvement in RA in vivo.

Cyclin-dependent kinase inhibitor, p21WAF1/CIP1, is involved in adipocyte differentiation and hypertrophy, linking to obesity, and insulin resistance

Both adipocyte hyperplasia and hypertrophy are determinant factors for adipocyte differentiation during the development of obesity. p21(WAF1/CIP1), a cyclin-dependent kinase inhibitor, is induced during adipocyte differentiation; however, its precise contribution to this process is unknown. Using both in vitro and in vivo systems, we show that p21 is crucial for maintaining adipocyte hypertrophy and obesity-induced insulin resistance. The absence of p21 in 3T3-L1 fibroblasts by RNA-mediated interference knockdown or in embryonic fibroblasts from p21(-/-) mice impaired adipocyte differentiation, resulting in smaller adipocytes. Despite normal adipose tissue mass on a normal diet, p21(-/-) mice fed high energy diets had reduced adipose tissue mass and adipocyte size accompanied by a marked improvement in insulin sensitivity. Knockdown of p21 in enlarged epididymal fat of diet-induced obese mice and also in fully differentiated 3T3-L1 adipocytes caused vigorous apoptosis by activating p53. Thus, p21 is involved in both adipocyte differentiation and in protecting hypertrophied adipocytes against apoptosis. Via both of these mechanisms, p21 promotes adipose tissue expansion during high fat diet feeding, leading to increased downstream pathophysiological consequences such as insulin resistance.

Crucial role of a long-chain fatty acid elongase, Elovl6, in obesity-induced insulin resistance

Insulin resistance is often associated with obesity and can precipitate type 2 diabetes. To date, most known approaches that improve insulin resistance must be preceded by the amelioration of obesity and hepatosteatosis. Here, we show that this provision is not mandatory; insulin resistance and hyperglycemia are improved by the modification of hepatic fatty acid composition, even in the presence of persistent obesity and hepatosteatosis. Mice deficient for Elovl6, the gene encoding the elongase that catalyzes the conversion of palmitate to stearate, were generated and shown to become obese and develop hepatosteatosis when fed a high-fat diet or mated to leptin-deficient ob/ob mice. However, they showed marked protection from hyperinsulinemia, hyperglycemia and hyperleptinemia. Amelioration of insulin resistance was associated with restoration of hepatic insulin receptor substrate-2 and suppression of hepatic protein kinase C epsilon activity resulting in restoration of Akt phosphorylation. Collectively, these data show that hepatic fatty acid composition is a new determinant for insulin sensitivity that acts independently of cellular energy balance and stress. Inhibition of this elongase could be a new therapeutic approach for ameliorating insulin resistance, diabetes and cardiovascular risks, even in the presence of a continuing state of obesity.

Preliminary application and evaluation of loop-mediated isothermal amplification (LAMP) for detection of bovine theileriosis and trypanosomosis in Tanzania : research communication

The sensitivity of LAMP, PCR and microscopy to detect Theileria spp. and Trypanosoma congolense in field-derived bovine blood samples from Tanzania was evaluated and compared. No parasites were detected by microscopy. Furthermore, no bovine Theileria spp. were detected by LAMP and PCR from all the 24 samples collected from Arusha. Four and one out of 24 samples were positive for Theileria congolense infection by LAMP and PCR respectively while, 18 and nine out of 40 samples from Dar es Salaam were positive by LAMP and PCR for Theileria spp. Infection, respectively. Although all samples from Dar es Salaam were negative for Trypanosoma congolense infections by PCR, 12 out of 40 samples were LAMP positive. Whilst PCR is an established gene amplification method for the detection of Theileria and trypanosome parasites, this study introduces LAMP as an alternative molecular diagnostic tool that could be used in large-scale epidemiological surveys.

A transcription factor of lipid synthesis, sterol regulatory element-binding protein (SREBP)-1a causes G(1) cell-cycle arrest after accumulation of cyclin-dependent kinase (cdk) inhibitors

Sterol regulatory element-binding protein (SREBP)-1a is a unique membrane-bound transcription factor highly expressed in actively growing cells and involved in the biosynthesis of cholesterol, fatty acids, and phospholipids. Because mammalian cells need to synthesize membrane lipids for cell replication, the functional relevance of SREBP-1a in cell proliferation has been considered a biological adaptation. However, the effect of this potent lipid-synthesis activator on cell growth has never been explored. Here, we show that induction of nuclear SREBP-1a, but not SREBP-2, completely inhibited cell growth in inducible Chinese hamster ovary (CHO) cell lines. Growth inhibition occurred through G(1) cell-cycle arrest, which is observed in various cell types with transient expression of nuclear SREBP-1a. SREBP-1a caused the accumulation of cyclin-dependent kinase (cdk) inhibitors such as p27, p21, and p16, leading to reduced cdk2 and cdk4 activities and hypophosphorylation of Rb protein. In contrast to transactivation of p21, SREBP-1a activated p27 by enhancing stabilization of the protein through inhibition of SKP2 and KPC1. In vivo, SREBP-1a-expressing livers of transgenic mice exhibited impaired regeneration after partial hepatectomy. SREBP-1-null mouse embryonic fibroblasts had a higher cell proliferation rate than wild-type cells. The unexpected cell growth-inhibitory role of SREBP-1a provides a new paradigm to link lipid synthesis and cell growth.

Trabecular angle of the human talus is associated with the level of cartilage degeneration

The architecture of bone trabeculae is based on the direction of stresses applied to the bone. The human talar dome receives compressive forces from the tibia and, to a much lesser extent, the fibula when standing, walking, and running, and transmits the force downward to the calcaneus through the talar body and anterior to the navicular via the talar head. As a result, the body of the talus has predominately vertical trabeculae. However, here we hypothesize that cartilage degeneration at the articular surface is associated with trabecular angle within the associated bone, as a reflection of joint alignment and/or biomechanics (stability, congruence, angulation, etc). Through measurement of trabecular angle with Fast Fourier Transform Analysis, we show a positive correlation between the cartilage degeneration score of the articular surface of the talar dome and the angle of trabecular deviation from the perpendicular axis of the dome (right talus R=0.75, p<0.01; left talus R=0.79, p<0.01).

Distinct effects of pravastatin, atorvastatin, and simvastatin on insulin secretion from a beta-cell line, MIN6 cells

In addition to the prevention of cardiovascular diseases by lowering plasma LDL cholesterol, recent studies suggest that statins could have some impact on insulin action. To estimate the direct effects of statins on insulin secretion from pancreatic beta-cells, MIN6 cells were treated with pravastatin, simvastatin, or atorvastatin. Basal insulin secretion at low glucose concentration was unexpectedly increased at very high doses of simvastatin or atorvastatin after 24- and 48-hour incubation. Insulin secretion at high glucose was not significantly changed, and thus, net glucose-stimulated insulin secretion was apparently decreased by these lipophilic statins. The changes in insulin secretion were highly associated with increased endogenous SREBP activities in response to HMG-CoA inhibition as estimated by SRE-luciferase assays, and finally after 48-hour incubation, accompanied by impaired cell viability as estimated by MTT assays. In contrast, these changes were much less prominent by the addition of pravastatin. Meanwhile, glucose-stimulated insulin secretion of islets isolated from C57BL/6 mice was not significantly changed by any of the statins. Overall, taken up by beta-cells, statins can affect insulin secretion through either HMG-CoA inhibition or cytotoxicity, as observed by the addition of extraordinary high doses of lipophilic statins, but not hydrophilic statins, to the medium.

CT and MRI findings of intraosseous schwannoma of the mandible: a case report

We report the radiographical findings of a rare case of intraosseous schwannoma of the mandible. The tumour that presented as a unilocular, well-defined, radiolucent lesion on plain radiography was located in the molar region. On CT, the tumour was a well-demarcated mass with no periosteal reaction and no destruction of the bone cortex. Destructive changes in the cortical wall of the mandibular canal by the tumour were observed on CT, but no evidence of dilatation and shift in the inferior mandibular canal was seen. MR imaging revealed that the mandibular canal was encased by the tumour as a solid mass without cystic parts. The signal intensity of the tumour was non-specific on MRI. Characteristics of intraosseous schwannoma in the mandible are the encasement of the canal by a well-demarcated tumour without periosteal reaction and the destruction of mandibular bone cortex. The destructive change of the inferior mandibular canal can be observed on CT and MRI. However, a biopsy is necessary to make the final diagnosis because of the non-specificity of the findings.

A trypanosome species isolated from naturally infected Haemaphysalis hystricis ticks in Kagoshima Prefecture, Japan

Common arthropod vectors for trypanosomes are flies, fleas and bugs. This study reports on an unknown trypanosome species isolated from naturally infected Haemaphysalis hystricis ticks, hereby, referred to as Trypanosoma KG1 isolate. The parasite has been successfully cultured in vitro with L929 or HEK 293T cell line as feeder cells. This trypanosome cannot survive in vitro without feeder cells. Following experimental infections of ticks, the trypomastigote-like and the epimastigote-like forms of this trypanosome could be detected by Giemsa-stained smears of the midgut and salivary glands of Ornithodoros moubata ticks which were made to feed on a culturing medium containing Trypanosoma KG1 isolate through an artificial membrane. Trypanosoma KG1 isolate could also be detected from Giemsa-stained smears of the haemolymph up to 30 days post-inoculation into the O. moubata haemocoel. Trypanosoma KG1 isolate cannot be propagated in laboratory animals including mice, rats, rabbits and sheep. A phylogenetic tree constructed with the 18S rRNA gene indicates that Trypanosoma KG1 is a member of the stercorarian trypanosomes.

Protein kinase A suppresses sterol regulatory element-binding protein-1C expression via phosphorylation of liver X receptor in the liver

Sterol regulatory element-binding protein (SREBP)-1c is a transcription factor that controls synthesis of fatty acids and triglycerides in the liver and is highly regulated by nutrition and hormones. In the current studies we show that protein kinase A (PKA), a mediator of glucagon/cAMP, a fasting signaling, suppresses SREBP-1c by modulating the activity of liver X receptor alpha (LXRalpha), a dominant activator of SREBP-1c expression. Activation of PKA repressed LXR-induced SREBP-1c expression both in rat primary hepatocytes and mouse livers. Promoter analyses revealed that the LXRalpha-binding site in the SREBP-1c promoter is responsible for PKA inhibitory effect on SREBP-1c transcription. In vitro and in vivo PKA directly phosphorylated LXRalpha, and the two consensus PKA target sites (195, 196 serines and 290, 291 serines) in its ligand binding/heterodimerization domain were crucial for the inhibition of LXR signaling. PKA phosphorylation of LXRalpha caused impaired DNA binding activity by preventing LXRalpha/RXR dimerization and decreased its transcription activity by inhibiting recruitment of coactivator SCR-1 and enhancing recruitment of corepressor NcoR1. These results indicate that LXRalpha is regulated not only by oxysterol derivatives but also by PKA-mediated phosphorylation, which suggests that nutritional regulation of SREBP-1c and lipogenesis could be regulated at least partially through modulation of LXR.

Immunization with recombinant beta-tubulin fromTrypanosoma evansiinduced protection againstT. evansi,T. equiperdumandT. b. bruceiinfection in mice

The beta-tubulin gene of Trypanosoma evansi (STIB 806) was cloned and expressed in Escherichia coli. The predicted amino acid sequence of T. evansi beta-tubulin shows 100%, 99.8%, 99.1%, and 98.6% homology with T. equiperdum, T. b. brucei, T. cruzi and T. danilewskyi, respectively, but is diverse from that of T. cyclops, showing only 51.6% of homology. Recombinant beta-tubulin was expressed as inclusion bodies in E. coli. It was purified and renatured for immunological studies. Mice immunized with the renatured recombinant beta-tubulin were protected from lethal challenge with T. evansi STIB 806, T. equiperdum STIB 818 and T. b. brucei STIB 940, showing 83.3%, 70% and 76.7% protection, respectively. Serum collected from the rabbit immunized with recombinant beta-tubulin inhibited the growth of T. evansi, T. equiperdum and T. b. brucei in vitro. Serum from mice and rabbits immunized with recombinant beta-tubulin recognized only T. evansi beta-tubulin and not mouse beta-tubulin. The results of this study demonstrated that the recombinant T. evansi beta-tubulin is a potential candidate for the development of a vaccine to prevent animal trypanosomiasis caused by these three trypanosome species.

A new technique for endoscopic submucosal dissection for early gastric cancer using an external grasping forceps

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) has improved the success rate of en-bloc resection. We report here on a new technique using an external grasping forceps.

PATIENTS AND METHODS

A total of 25 patients with suitable EGCs over 10 mm in diameter located in the gastric body were enrolled. After submucosal injection followed by circumcision of the lesion with a needle-knife, an external grasping forceps was introduced with the help of a second grasping forceps and anchored at the distal margin of the lesion. With gentle oral traction applied with this forceps, the lesion was dissected endoscopically in retroversion from the aboral side.

RESULTS

The mean lesion size was 15.0 mm (range 10 - 25 mm). Using the technique described, all lesions could be resected en bloc with free margins. The mean procedure time was 45 min (range 30 - 80 minutes). No significant bleeding requiring blood transfusion or perforation occurred.

CONCLUSIONS

This technical modification may simplify and shorten the gastric ESD procedure, except for lesions in distal locations, without compromising the efficacy.

β-Glucosidase inhibitory activities of phenylpropanoid glycosides, vanicoside A and B from Polygonum sachalinense rhizome

The phenylpropanoid glycosides, vanicoside A and B, isolated from rhizomes of giant knotweed (Polygonum sachalinense) showed beta-glucosidase inhibitory activity, with IC(50) values of 59.8 and 48.3 mug/ml (59.9 and 50.5 muM), respectively. In contrast, p-coumaric acid and ferulic acid, corresponding to phenylpropanoyl moieties of vanicosides, exhibited very little inhibition.

Static bone cavity of the mandible: Computed tomography findings with histopathologic correlation

PURPOSE

To review computed tomography (CT) findings of histopathologically examined static bone cavities in order to determine whether an additional pathogenesis may play a role in this disease.

MATERIAL AND METHODS

Four patients with histopathologically examined static bone cavities were included in this retrospective study. Location, appearance of bone remodeling, tissue characteristics, and contrast enhancement of the cavity were assessed on CT images. CT findings were then compared with the histopathological findings.

RESULTS

Static bone cavity was found in the lingual molar region in three patients and in the lingual cuspid region of the mandible in one patient. Both fatty and soft tissues were present in the cavities of all four patients. Attenuation of the soft tissue in the cavities was found to be different from that of the submandibular gland. The soft tissue showed enhancement with contrast-enhanced CT in three patients. For all patients, the histopathologic content of the static bone cavity included fat, soft tissue, and abnormal vasculature. The thickened vein wall in the abnormal vasculature was observed. Aberrant tissue of the submandibular gland was not found in any of the static bone cavities.

CONCLUSION

Contrast enhancement of the soft tissue on the contrast-enhanced CT images suggests the presence of vasculature in the cavities. Histopathological examination confirmed the presence of fatty tissue and dilated abnormal vessels, and the absence of salivary gland tissue in the cavities. These findings show that vascular structures are prominent in tissues found in static bone cavities.

Insulin resistance and impaired myocardial fatty acid metabolism in dialysis patients with normal coronary arteries

We investigated whether insulin resistance is associated with impaired cardiac fatty acid metabolism in maintenance hemodialysis patients without coronary artery disease. We studied 55 nondiabetic (63+/-11 years old) and 51 diabetic (61+/-10 years old) hemodialysis patients with normal coronary arteries, using single-photon emission computed tomography (SPECT) with an iodinated fatty acid analogue, iodine-123-beta-methyl iodophenyl-pentadecanoic acid ((123)I-BMIPP), to evaluate cardiac fatty acid metabolism. SPECT imaging was graded regionally from 0 (normal) to 4 (absence of tracer) to calculate a summed score for 17 left ventricular segments. Insulin resistance was determined using the homeostasis model assessment index of insulin resistance (HOMA-IR). HOMA-IR correlated with summed BMIPP score in nondiabetic and diabetic patients. Stepwise multiple regression analysis showed that HOMA-IR was independently associated with BMIPP summed score in nondiabetic (beta=0.774, t=9.218, P=0.0001) and diabetic patients (beta=0.792, t=9.079, P=0.0001). Left ventricular ejection fraction was lower in nondiabetic subjects with BMIPP summed score of at least 6 plus HOMA-IR of at least 4 than in others with lower values for both assessments (53.1+/-13.8%, n=20 vs 67.7+/-9.1%, n=23, P=0.0002); this was also true in diabetic subjects (50.9+/-15.2%, n=24 vs 71.0+/-13.6%, n=11, P=0.0007). Association between insulin resistance and impaired cardiac fatty acid metabolism may contribute to left ventricular dysfunction in patients with maintenance hemodialysis without coronary diseases.

Expression of foreign type I ribulose-1,5-bisphosphate carboxylase/ oxygenase (EC 4.1.1.39) stimulates photosynthesis in cyanobacterium Synechococcus PCC7942 cells

A reporter gene assay revealed that promoters derived from Synechococcus PCC7942 (S.7942) psbAI and Synechocystis PCC6803 (S.6803) psbAII were suitable for the expression of foreign ribulose-bisphosphate carboxylase (RuBisCO; EC 4.1.1.39) in S.7942 cells. Transformational vectors with a promoter and a foreign RuBisCO gene, cvrbc originated from Allochromatium vinosum, were constructed on a binary vector, pUC303, and introduced to S.7942 cells. When the cvrbc was expressed with the S.7942 psbAI promoter, the total RuBisCO activity increased 2.5- to 4-fold than that of the wild type cell. The S.6803 psbAII promoter increased the activity of the transformant 1.5-2 times of that of wild type cell. There was a significant increase in the rate of photosynthesis depending on the increase of RuBisCO activity. The maximum rate of photosynthesis of the transformant cell was 1.63 times higher than that of the wild type under the illumination of 400 micromol m(-2) s(-1), at 20 mM bicarbonate and at 30 degrees C. Although the photosynthesis of the higher plant is limited by the ability of photosystems under high irradiance and the high CO(2 )concentration, that of the S.7942 cell is limited by the RuBisCO activity, even at high CO(2) concentrations and under high irradiance.

Spectroscopic characterization of an ultrashort-pulse-laser-driven Ar cluster target incorporating both Boltzmann and particle-in-cell models

A model that solves simultaneously both the electron and atomic kinetics was used to generate a synthetic He alpha and satellite x-ray spectra to characterize a high intensity ultrashort laser driven Ar cluster target experiment. In particular, level populations were obtained from a detailed collisional-radiative model where collisional rates were computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. In addition, a particle-in-cell simulation was used to model the laser interaction with the cluster target and provided the initial electron energy distribution function (EEDF) for the Boltzmann solver. This study suggests that a high density average, <Na>high, of 3.2 x 10(20) cm(-3) was held by the system for a time, delta tau, of 5.7 ps, and during this time the plasma was in a highly nonequilibrium state in both the EEDF and the ion level populations.

Additive enhancement of implant fixation following combined treatment with rhTGF-beta2 and rhBMP-2 in a canine model

BACKGROUND

Gaps at the interface between implant and bone increase the risk of diminished implant fixation and eventual loosening. The purpose of the present study was to determine if combined use of recombinant human transforming growth factor-beta 2 (rhTGF-beta2) and bone morphogenetic protein 2 (rhBMP-2) led to greater implant fixation strength in the presence of interface gaps than the use of either growth factor alone.

METHODS

Twenty-eight skeletally mature adult male dogs received one porous-coated titanium implant in the proximal part of each humerus, for a total of fifty-six implantation sites. Spacers were used to establish an initial 3-mm gap between the implant and the host bone at all fifty-six sites. Forty-two implants were coated with hydroxyapatite-tricalcium phosphate and were used in three growth-factor-treatment groups in which the implants placed in the left humerus were loaded with 12 microg of rhTGF-beta2 (Group 1, seven animals), 25 microg of rhBMP-2 (Group 2, seven animals), or 12 microg of rhTGF-beta2 combined with 25 microg of rhBMP-2 (Group 3, seven animals). In these animals, the twenty-one implants that were placed in the right humerus were loaded with buffer only to serve as contralateral controls. In Group 4 (seven animals), the implants were not coated with hydroxyapatite-tricalcium phosphate, the gap in the left humerus was lightly packed with autogenous bone graft, and the gap in the right humerus was left empty to serve as a contralateral control. All animals were killed at twenty-eight days. The primary end points included three mechanical variables: fixation strength, interface stiffness, and energy to failure. Secondary end points included bone ingrowth and bone volume and trabecular architecture in the gap and in a region located 2 mm medial to the implantation site.

RESULTS

The hydroxyapatite-tricalcium phosphate coating had no effect on implant fixation, bone ingrowth, or bone formation in the 3-mm gap. Individual growth factor treatments led to 2.3 to 3.2-fold increases in fixation strength and stiffness as compared with the values for the contralateral controls (p < 0.05). The combined growth factor treatment led to 5.7-fold increases in fixation strength and stiffness compared with the values for the contralateral controls (p < 0.01). Autogenous bone graft treatment was associated with 4.5 to 6.4-fold increases in implant fixation strength and stiffness as compared with the values for the contralateral controls (p < 0.01). Compared with the relevant contralateral controls, energy to failure was increased 3.5-fold in association with TGF-beta2 alone (p < 0.05), 4.5-fold in association with TGF-beta2 combined with BMP-2 (p < 0.01), and 2.5-fold in association with autogenous bone-grafting. As much as 63% of the variance in the mechanical end points was associated with variance in bone volume and architecture in the 3-mm gap and in the region of interest located 2 mm medial to the implantation site (p < 0.01).

CONCLUSIONS

In this animal model, the combined use of TGF-beta2 and BMP-2 led to more secure mechanical fixation of the implant than did the use of either growth factor alone and demonstrated results that were similar to those associated with the use of autogenous bone graft.

Adenovirus serotype 35 vector-mediated transduction into human CD46-transgenic mice

We previously demonstrated that systemic administration of adenovirus serotype 35 (Ad35) vectors to mice does not mediate efficient transduction in organs, probably because expression of the mouse analog of the subgroup B Ad receptor, human CD46 (membrane cofactor protein), is limited to the testis. Here, we describe the in vitro and in vivo transduction characteristics of Ad35 vectors by using homozygous and hemizygous human CD46-transgenic (CD46TG) mice, which ubiquitously express human CD46. An Ad35 vector more efficiently transduced the primary dendritic cells and macrophages prepared from CD46TG mice than those from wild-type mice. In vivo transduction experiments demonstrated that CD46TG mice are more susceptible to Ad35 vector-mediated in vivo transduction than are wild-type mice. In particular, homozygous CD46TG mice, which express higher levels of CD46 in the organs than hemizygous CD46TG mice, tend to exhibit higher transduction efficiencies after intraperitoneal administration than hemizygous CD46TG mice. Intraperitoneal administration of Ad35 vectors resulted in efficient transduction into the mesothelial cells of the peritoneal organs in homozygous CD46TG mice. These results indicate that an Ad35 vector recognizes human CD46 as a cellular receptor in CD46TG mice. However, the in vivo transduction efficiencies of Ad35 vectors in CD46TG mice are much lower than those of conventional Ad5 vectors in wild-type mice.