bluuebunny/crossref_metadata_2025 huggingface dataset:
Synovitis in legg-calvé-perthes disease
Authors: Hochbergs P. , Eckerwall G. , Egund N. , Jonsson K. , Wingstrand H.
Published: January 2010

Purpose: to evaluate, by means of MR imaging, the degree and persistence of synovitis in the hip joint in Legg-Calvé-Perthes disease and to correlate the degree of synovitis with the degree of epiphyseal necrosis

Material and Methods: A total of 170 MR images in 72 patients (84 hips) were examined. the T2-weighted MR images were taken in the coronal plane in order to evaluate the degree of synovitis in the hip joint

Results: MR revealed synovitis in all cases in the early phase of the disease. in Catterall group II, synovitis was discreet to moderate for up to 6 months after diagnosis. Hips with more severe necrosis, Catterall groups III and IV, had moderate or intense degrees of synovitis. There was a correlation between the degree of synovitis and the lateral pillar classification according to HERRING et al. Also, there was a good correlation between the extent of signal changes in the epiphysis on MR imaging and the degree of synovitis. There was no difference when signal changes were evaluated on T1- or T2-weighted images. Signs of synovitis could be seen for up to 30 months after diagnosis in Catterall group I hips, and in Catterall groups II and III for up to 36 months, and in 2 cases even longer. Some Catterall group IV hips had discreet or mild synovitis for 60 months or more, after diagnosis

Conclusion: the degree of synovitis on MR imaging correlates to the extent of epiphyseal necrosis seen on radiographs or MR imaging as well as to the lateral pillar classification, i.e. to a poor clinical outcome. in Catterall group IV hips, synovitis can even persist for up to 60 months after diagnosis
Bone mineral density and spongiosa architecture in correlation to vertebral body insufficiency fractures
Authors: Andresen R. , Radmer S. , Banzer D.
Published: January 2010

Objective: the clinical value of spinal quantitative CT (sQCT) and the structural patterns of the vertebral bone were studied

Material and Methods: sQCT was performed on 246 patients with a mean age of 57 years for whom conventional lateral radiographies of the thoracic and lumbar spine were available. All patients were suffering from back pain of unknown etiology. the bone mineral density (BMD) of the midvertebral section of 3 lumbar vertebral bodies was determined by means of single-energy-(SE)-weighted QCT (85 kV). Spongiosa architecture and density profile analyses were made in the axial images. This was contrasted to BMD values ascertained in SE QCT. the mean BMD was compared to the number of fractures and the patients were divided into three groups: group I — no fracture; group II — one fracture; and group III 1 fracture

Results: the mean BMD was: 134.3 (74.1–187.5) mg hydroxyapatite (HA)/ml in group I; 79.6 (58.6–114.3) mg HA/ml in group II; and 52.4 (13.1–79.1)mg HA/ml in group III. A significant deterioration in spongiosa structure was found with increasing demineralization: strongly rarefied patterns predominated in the fracture groups II and III

Conclusion: sQCT provides a good risk assessment of the occurrence of vertebral body insufficiency fractures
MR appearance of anomalous insertion of the medial meniscus
Authors: Arjun S. , Takahashi S. , Tang Y. , Nakane N. , Yonemitsu H.
Published: January 2010

We report on the MR imaging of an anomalous medial meniscus with a tear in a 41-year-old man. Anomaly of the medial meniscus is rare and difficult to diagnose clinically. the MR images contributed to the pre-arthroscopic diagnosis and arthroscopy confirmed the lesion. the anomalous meniscus was not related to the symptoms
Colour doppler imaging of shunts from the left portal branch in portal hypertension
Authors: Nilsson A. , Olofsson P.-Å. , Lorén I. , Nilsson P.
Published: January 2010

Purpose: to describe the typical colour Doppler appearance of a shunt through the parenchyma of the left lobe of the liver in portal hypertension

Material and Methods: Ultrasound images of 141 patients with biopsy-verified cirrhosis were reviewed. Special note was taken of the appearance of shunts from the left portal branch

Results: in 28 patients, shunts from the left portal branch were detected ultra-sonographically, 10 of which ran through the liver parenchyma on a course separated from the ligamentum teres. Seven of these 10 followed a tortuous course just below the surface of the liver creating a ball or corkscrew-like pattern

Conclusion: Shunts from the left portal branch are not uncommon and may represent the only ultrasonographically detectable pathology in these patients. Recognition of the typical pattern will facilitate their detection
Changes in tissue oxygen tension caused by contrast media injected into the femoral artery of the dog
Authors: Nitahar K. , Uchida K. , Nakai T. , Hashimoto K. , Sato T. , Dan K.
Published: January 2010

Purpose: to document changes in tissue oxygen tension as measured directly in an area perfused with contrast medium

Material and Methods: Changes in tissue oxygen tension in response to the injection of ionic and non-ionic contrast media into the femoral arteries were measured in the femoral adductor (proximal) and gastrocnemius (distal) muscles of 8 dogs. Amidotrizoic acid and iopamidol were injected in two different iodine concentrations (370 mg I/ml and 185 mg I/ml respectively) and tissue oxygen tension in the proximal and distal muscles was monitored continuously using polarographic needle electrodes

Results and Conclusion: A transient decrease and subsequent increase of muscle tissue oxygen tension were observed after the injection. the extent of these changes depended on the concentration and osmolality of the medium. to minimize changes in peripheral tissue oxygen tension, contrast media with low osmolality and low concentration are recommended for femoral angiography
Correlation between dose rate and T1 in blood at gd-enhanced MR angiography
Authors: Johansson L. O. M. , Ahlström H. K.
Published: January 2010

Purpose: to determine the correlation between dose rate and T1 in blood at Gd-enhanced MR angiography (MRA)

Material and Methods: A test dose of contrast agent was used to calculate the time delay between injection and arrival in the abdominal aorta. the dose rate was expressed as ml · kg b.w.−1 · s−1. the correlation between dose rate and T1 was determined by varying the dose rate while keeping the scanning and infusion times constant. the signal intensity in the abdominal aorta was measured during the first pass of Gd and compared with markers of known T1 values

Results: A correlation between dose rate and T1 in blood was obtained

Conclusion: A Gd dose rate of 0.01 ml · kg b.w.−1 · s−1 gives a T1 in blood of 100 ms. This can be used to calculate the optimal pulse sequence for contrast-enhanced MRA
Testicular microlithiasis — a possibly premalignant condition
Authors: Berger A. , Brabrand K.
Published: January 2010

Testicular microlithiasis (TM) is a rare condition characterized by the presence of multiple small intratesticular calcifications. the etiology is unknown but the condition has been observed in a variety of different urological conditions. We report on 5 cases diagnosed by ultrasonography at our departments from 1992 to 1994

A review of the literature plus our present 5 cases gives a total of 124 reported cases of TM. TM was associated with testicular malignancy in 44 patients (35%) of whom 24 (19%) had a seminoma and 20 (16%) a non-seminoma. There were 4 reports of testicular malignancy developing in patients with a prior diagnosis of TM. the condition should be considered premalignant and a careful follow-up of TM patients is advocated
Atypical CT findings of cervical lymphadenopathy due to Hodgkin's disease
Authors: Daskalogiannaki M. , Prassopoulos P. , Rovithi I. , Manganas E. , Bolioti S. , Gourtsoyiannis N.
Published: January 2010

We describe a case of Hodgkin's disease with cervical lymphadenopathy which may easily be confused with a granulomatous process both radiologically and pathologically
Stereotaxic core needle aspiration biopsy with multiple passes in nonpalpable breast lesions
Authors: Bolivar A. Vega , García E. Ortega , Ayensa F. Garijo
Published: January 2010

Objective: To compare the grade of histologic agreement between stereotaxic core needle aspiration biopsy (SCNAB) with multiple passes, and surgical excision.

Methods: A total of 180 patients with 182 nonpalpable breast lesions underwent SCNAB with multiple passes in an upright add-on stereotaxic device using a manual 1.8-mm needle (15 G). In this group, 125 patients underwent subsequent surgical excision.

Results: A SCNAB result indicative of malignancy (invasive or noninvasive carcinoma) was obtained in 68 (87%) of the 78 breast carcinomas (14 noninvasive and 64 invasive) and definitive surgical therapy with a one-stage procedure was performed. Complete or partial agreement between core biopsy and surgery was observed in 19 (86%) of 22 invasive or noninvasive carcinomas discovered by microcalcifications, 40 (97.5%) of 41 invasive carcinomas discovered by a mass, and 9 (60%) of 15 invasive or noninvasive carcinomas discovered by architectural distortion. Six (33%) of the 18 patients whose core biopsies showed noninvasive carcinoma had an invasive or microinvasive component at subsequent surgery.

Atypical hyperplasia or benign core biopsy was observed in 6 (8%) and 4 (5%) breast carcinomas respectively.

Conclusion: SCNAB with multiple passes is a reliable method for identifying nonpalpable lesions in patients with noninvasive or invasive carcinomas discovered by respectively microcalcifications or mass.
Radiographically negative stress-related bone injury
Authors: Hodler J. , Steinert H. , Zanetti M. , Frölicher U. , Rogala J. , Stumpe K. , von Schulthess G. K.
Published: January 2010

Purpose: To assess the diagnostic value of MR imaging relative to two-phase bone scintigraphy in radiographically negative stress-related injuries.

Material and Methods: Sixteen consecutive patients presenting with stressrelated bone injuries and normal standard radiographs were examined with two-phase bone scans and MR imaging. MR imaging protocols varied according to the region to be examined. The MR and scintigraphic images were evaluated blindly and separately by respectively two radiologists and two nuclear medicine physicians. The standard of reference was represented by a combination of clinical and scintigraphic findings as well as clinical follow-up.

Results: For MR imaging, sensitivity, specificity, and positive and negative predictive values for the presence of stress-related injuries for the two readers were 69/63%, 100/80%, 100/91%, and 50/40%, respectively. Interobserver agreement was good (kappa=0.62). For scintigraphy, all abnormal and normal findings were correctly identified.

Conclusion: For patients with clinically suspected stress-related injuries and a low probability of other active bone diseases (such as infection or neoplasm), bone scintigraphy should be the initial imaging modality.
Color doppler ultrasonography of soft-tissue masses
Authors: Lagalla R. , Iovane A. , Caruso G. , Lo Bello M. , Derchi L. E.
Published: January 2010

Purpose: To evaluate the capability of color Doppler ultrasonography to differentiate between benign and malignant soft-tissue tumors.

Material and Methods: We reviewed the ultrasonographic (US) and color Doppler (CD) findings in 46 consecutive patients with a palpable periskeletal mass. The presence of 3 or more vascular hila and of tortuous and irregular internal vessels within the lesions was considered an indication of malignancy. The CD diagnosis was compared with that obtained at US alone.

Results: The sensitivity and specificity of CD were respectively 85% and 92%; these values were higher than those obtained at US alone, respectively 75% and 50%. Arteriovenous malformations presented as lesions with large internal vessels that had low vascular impedance and were easily diagnosed. The waveform patterns within solid tumors were not specific.

Conclusion: At present, US is commonly employed to confirm the presence of a suspected soft-tissue mass, to locate it accurately, and to indicate its nature. CD findings enhance the role of the US technique in such lesions. The combined use of US and CD can allow the differentiation of benign from malignant lesions, and thus provide a better basis for treatment.
Evaluation of dmsa scintigraphy and urography in assessing both acute and permanent renal damage in children
Authors: Stokland E. , Hellström M. , Jacobsson B. , Jodal U. , Sixt R.
Published: January 2010

Purpose: To evaluate dimercaptosuccinic acid (DMSA) scintigraphy and urography in the detection of renal involvement in children with urinary tract infection (UTI) in order to identify patients with a high risk of developing renal damage.

Material and Methods: A total of 157 children (median age 0.4 years, range 5 days to 5.8 years) with first-time symptomatic UTI were examined scintigraphy (with an assessment of renal area involvement) and urography at the time of UTI and 1 year later. All evaluations were made blindly.

Results: Of the total 314 kidneys, 80 (25%) were abnormal at initial scintigraphy. Of these 80 kidneys, 44 (55%) had normalized at follow-up. Of the 234 initially normal kidneys, 29 (12%) were abnormal at follow-up. One year after UTI, abnormalities were seen in 59 children at scintigraphy and in 18 children at urography. Renal area involvement was larger and split function abnormalities more common in kidneys that were abnormal at both scintigraphy and urography than in kidneys with only scintigraphic abnormalities.

Conclusion: Quantitation of renal area involvement and split renal function at early scintigraphy would seem to be useful in identifying patients at risk of developing renal damage. Urography at 1 year after infection identified mainly those with the most severe scintigraphic abnormalities. The clinical importance of scintigraphic abnormalities that are not confirmed by urography is not known.
Central Assessment of Bilateral Phlebograms in a Major Multicentre Thromboprophylactic Trial
Authors: Kälebo P. , Eriksson B. I. , Zachrisson B. E.
Published: January 2010

Purpose: To determine the cause of inadequate bilateral phlebograms at central assessment. A major antithrombotic trial was evaluated to identify and apply corrective measures for reducing inadequate results in future multicentre trials.

Material and Methods: The inadequate results in 253 out of 1,827 patients having undergone bilateral phlebography following total hip replacement were reviewed by two central assessors using strict criteria for evaluability. The reasons for inadequate findings were assessed and ranked.

Results and Conclusion: Insufficient contrast filling, especially of the anterior tibial, common femoral and iliac veins, was the most common reason for disqualifying examinations. Unilateral examinations and obscuring metallic devices were the second and third most common reasons, respectively. Efforts should be made to standardize the phlebography technique, to use a large volume of contrast without tourniquets, and to obtain an appropriate number of views to visualize the deep veins.
Respiratory Monitoring during MR Imaging
Authors: Larsson C. , Davidsson L. , Lundin P. , Gustafsson G. , Vegfors M.
Published: January 2010

Purpose: To assess the clinical utility of a fibre-optical monitor for respiratory monitoring in patients undergoing MR imaging without general anaesthesia.

Material and Methods: One hundred consecutive patients were included at each of 3 MR units (300 patients in total). The technicians estimated the value of monitoring the respiratoy rate on a 5-graded scale. Conditions that might complicate the MR examination were noted.

Results: The respiratory monitor was well tolerated by 99% of the patients. It was rated as valuable or very valuable in one-third of the total group, but in slightly more than two-thirds of the group of patients with some condition that might have complicated the MR examination. The estimated value of respiratory rate monitoring did not correlate to the age or sex of the patients, the type of examination, or to whether contrast medium was used or not, but it was significantly more often considered valuable in patients placed in the headfirst position than in those placed in feet-first.

Conclusion: Respiratory rate monitoring during MR imaging seems to be valuable in many patients, particularly if some condition that might complicate the MR examination is present.
Thymus Size in Preterm Infants Evaluated by Ultrasound
Authors: Hasselbalch H. , Jeppesen D. L. , Ersbøll A. K. , Nielsen M. B.
Published: January 2010

Purpose: To sonographically evaluate the thymic size in preterm infants.

Material and Methods: In 6 healthy infants, born in gestational weeks 34-37, and 6 infants born in weeks 24-32, the thymic volume estimate (the thymic index) was assessed. The measurements were compared to the estimates calculated from the prediction model for neonates.

Results: The slightly preterm infants fit the prediction model. In cases where the results failed to fit into the model, it was adjusted in order to cover lower birth rates. The extremely preterm infants initially had a very low thymic index but, when healthy, they reached the normal range.

Conclusion: With the knowledge of the birth weight it is now possible to predict the thymic size in healthy infants weighing 2,070 g or more.
Thymus Size in Infants from Birth until 24 Months of Age Evaluated by Ultrasound
Authors: Hasselbalch H. , Ersbøll A. K. , Jeppesen D. L. , Nielsen M. B.
Published: January 2010

Purpose: To do a follow-up sonography assessment of the thymic size in infants at an age of 24 months, and to create a longitudinal prediction model for the thymic index covering all ages from birth to 24 months.

Material and Methods: of 37 infants examined in an earlier investigation, 34 attended a 24-month follow-up examination. The thymic index, a volume estimate, was assessed by sonography and compared to clinical variables, breastfeeding status and illness. The longitudinal prediction model was based on data throughout 2 years.

Results: There was no significant relation between the thymic index and the clinical variables, breast-feeding status or illness at 24 months. An overall test for the effect of breast-feeding status at 4 months for infants from 0-24 months was significant, as was the actual body length of the infants from 0-8 months. Prediction models were estimated.

Conclusion: Based on a 24-month longitudinal sonography study, prediction models are presented whereby the thymic size, as an index, can be predicted at all times from birth to 24 months of age.
Plain Radiography of the Lumbosacral Spine
Authors: Espeland A. , Albrektsen G. , Larsen J. L.
Published: January 2010

Purpose: To evaluate how referrals from Norwegian general practitioners for plain radiography of the lumbosacral spine conform to clinical recommendations, and whether non-conforming referrals yield important findings.

Material and Methods: The clinical information reported in referral letters of 323 patients was compared with recommendations given in a Norwegian and in a British “guide”. Additional clinical data were obtained by interviewing 100 of the patients. Using all available information, a new comparison was performed. Radiological findings were obtained from the routine reports.

Results: of the 323 referrals, 24% (37%) conformed to the Norwegian (British) “guide”, 34% (46%) did not conform, and 42% (18%) were considered uncertain, mainly because of lack of pertinent information in the referral letters. A total of 182 examinations were in disagreement with one or both “guides”. Only 4 of these examinations revealed potentially important findings (osteoporotic fractures in 2 patients, uncertain sacroiliac joint arthritis in 1 patient, and “probably benign” sclerotic densities in 1 patient). In the interview group, the proportion of non-conforming referrals was 40% (48%) based on the referral letters, and 31% (30%) when the interview data were taken into account.

Conclusion: A great proportion of referrals for plain radiography of the lumbosacral spine do not conform to recent clinical recommendations. Referrals outside the advised criteria yield few relevant findings and could probably be cancelled. They require at least supplementary information to justify radiography.
MR Evaluation of the Articular Cartilage of the Femoral Head during Traction
Authors: Nakanishi K. , Tanaka H. , Nishii T. , Masuhara K. , Narumi Y. , Nakamura H.
Published: January 2010

Objective: The purpose was to evaluate the articular cartilage of the hip joint with MR during traction and compare the findings with the resected specimen or arthroscopic findings.

Material and Methods: Eight healthy volunteers, 5 patients with osteonecrosis, 5 with acetabular dysplasia, and 5 with advanced osteoarthrosis underwent MR imaging to evaluate the articular cartilage of the hip joint. Coronal fat-suppressed 3D spoiled gradient-echo (SPGR) images were obtained during traction. Identical imaging was performed of all the resected femoral heads of the osteonecrosis and advanced osteoarthrosis patients, and was correlated with the macroscopic pathological findings.

Results: The traction was effective and the femoral articular cartilage was clearly identified in all 8 control subjects, and in all cases of osteonecrosis and acetabular dysplasia. In 4 cases of osteonecrosis, chondral fracture was identified in the boundary between the necrosis and the normal area. In all cases of advanced osteoarthrosis, cartilage was identified only at the medial side. The MR images of osteonecrosis and advanced osteoarthrosis corresponded well with the MR images of the resected femoral heads and the macroscopic findings.

Conclusion: Fat suppressed 3D-SPGR during continuous leg traction was useful in detecting cartilage abnormalities.
MR Imaging in Amyopathic Dermatomyositis
Authors: Lam W. W. M. , Chan H. , Chan Y. L. , Fung J. W. K. , So N. M. C. , Metreweli C.
Published: January 2010

Purpose: Amyopathic dermatomyositis is a distinct clinical entity with cutaneous involvement but no myopathy. We conducted a prospective study to investigate the role of MR imaging in these patients.

Material and Methods: Out of 40 Chinese patients presenting with dermatomyositis, based on clinical assessment and normal serum muscle enzymes 10 were diagnosed as having amyopathic dermatomyositis. These 10 patients underwent MR imaging for evaluation of any subclinical muscle involvement.

Results: Three patients demonstrated abnormal signal intensity in muscles on both T2- and fat suppression sequences. Thus, one-third of patients with dermatomyositis and clinically normal muscles may have detectable muscle inflammation on MR images, indicating that MR has a potential role for locating the relevant biopsy site and for longitudinal follow up. Six of the 10 patients had malignant disease diagnosed before or after diagnosis of the cutaneous manifestation. Nasopharyngeal carcinoma was the most common malignant disease in this group of patients.

Conclusion: MR imaging is recommended for demonstrating subclinical muscle involvement in patients with the clinical diagnosis of amyopathic dermatomyositis. We also recommend screening for malignancy, particularly nasopharyngeal carcinoma, in Southern Chinese patients with dermatomyositis.
Evaluation of the Pituitary Gland in Idiopathic Hypogonadotropic Hypogonadism
Authors: Jayasundar R. , Ammini A. C. , Gupta R. , Raghunathan P.
Published: January 2010

Purpose: Evaluation of the pituitary gland has been carried out in idiopathic hypogonadotropic hypogonadism (IHH) to test the potential of MR imaging in differentiating IHH patients from normals.

Material and Methods: Thirty-seven patients (aged 18-30 years), and 20 volunteers (aged 20-30 years) were studied by T1-weighted MR imaging. Length (LA and LP), height (H), width (W), area (AA and AP), and volume (V1A, V1B V2A, V2P) of the pituitary gland were determined. (Subscripts P and A refer to measurements made with and without the posterior lobe, respectively.) V1 and V2 were estimated using two different methods.

Results: In the control group, LB W and V2A exhibited significant differences between female and male volunteers. While W was the only parameter that did not show significant difference between normals and patients (in both men and women), all other parameters except LB H and AP showed statistically significant differences between normals and IHH patients in both males and females. While LP was significantly different between normals and patients (men), H and AP were significantly different between normals and patients only in the female group.

Conclusion: Correlation analysis between various parameters has shown that LA can be used for evaluating the pituitary in both the male and female IHH patients.
Time Dependence of Iopamidol and Iodixanol in Arthrography of the Knee
Authors: Carlier R.-Y. , Åkeson P. , Morvan G. , Kristoffersen D. T. , Amar C. , Vallée C.
Published: January 2010

Purpose: The safety and diagnostic efficacy of iodixanol (Visipaque) 270 mg I/ml was compared to that of iopamidol (Iopamiron) 300 mg I/ml in knee arthrography.

Material and Methods: This trial was a bi-center double-blind trial including 128 patients (iodixanol/iopamidol 64/64 patients). Efficacy was evaluated by blinded grading of the diagnostic quality of the p.a. images taken 0, 12 and 25 min after contrast administration by the examining radiologist and later at a consensus evaluation by two experienced skeletal radiologists. Adverse events were recorded.

Results: No patient experienced any adverse event. The proportion of better images at both 12 and 25 min after injection was higher in the iodixanol group compared to the iopamidol group both by the examining radiologist and at the consensus evaluation.

Conclusion: In the knee joint iodixanol is a safe contrast medium. The contrast effect of iodixanol lasted longer than that of iopamidol, which can be important when performing arthrography, especially CT arthrography, where the time between puncture and examination can be prolonged.
Center of infinitesimal Cherednik algebras of 𝔤𝔩_{𝔫}
Authors: Tikaradze Akaki
Published: January 2010

We show that the center of an infinitesimal Cherednik algebra of

g
l

n

\mathfrak {gl}_n

is isomorphic to the polynomial algebra of

n
n

variables. As consequences of this fact, we show that an analog of Duflo’s theorem holds and all objects in the category

O

\mathcal {O}

have finite length.
It's the Data!
Authors: Botstein David
Published: January 2010

Three articles from the early years of Molecular Biology of the Cell (MBoC) have had remarkably many citations in the literature since their publication ∼10 years ago. As a coauthor of these articles and the former editor of MBoC, I was asked for possible explanations. I believe the answer lies in the unusual nature of these articles: each presents and summarizes gene expression data for nearly every gene in the yeast or human genomes. Continuing interest in the data themselves by cell biologists, rather than results or conclusions drawn by the authors, best accounts for the citation history. The flatness of the numbers of citations over time, the continuing high rate of accesses to individual Web sites set up to allow searching and display of the underlying data, and the large fraction of citations in journals focused on mathematics and computation all support the same conclusion: it's the data.
A Developmental Journey and Lessons Learned Along the Way
Authors: Rossant Janet
Published: January 2010

A career in science is a journey of wonder and discovery. To succeed in science requires curiosity, perseverance, a good dose of luck, and wise guidance from those who have taken the journey ahead of you. We also need to use our science skills to contribute to public debate on complex issues of the day.
Walking Along the Serendipitous Path of Discovery
Authors: Walter Peter
Published: January 2010

Deciphering of the molecular mechanism of the “unfolded protein response” (UPR) provides a wonderful example of how serendipity can shape scientific discovery. Secretory and membrane proteins begin their journey to the cell surface in the endoplasmic reticulum (ER). Before leaving the organelle, proteins are quality-controlled, and only properly folded proteins are transported onwards. The UPR detects an insufficiency in the protein-folding capacity in the ER and in the ways of a finely tuned homeostat adjusts organelle abundance according to need. If the protein-folding defect in the ER cannot be corrected, the UPR switches from a cell-protective to a cell-destructive mode and activates apoptosis in metazoan cells. Such life or death decisions position the UPR in the center of numerous pathologies, including viral infection, protein-folding diseases, diabetes, and cancer. The UPR proved to be a rich field for serendipitous discovery because the molecular machines that transmit information about insufficient protein folding and activate appropriate gene expression programs function in unusual, unprecedented ways. A key regulatory switch in the UPR, for example, is a cytoplasmic, nonconventional mRNA spicing reaction, initiated by a bifunctional transmembrane kinase/endoribonuclease.
Intercellular calcium wave propagation in linear and circuit-like bone cell networks
Authors: Huo Bo , Lu Xin L. , Guo X. Edward
Published: January 2010

In the present study, the mechanism of intercellular calcium wave propagation in bone cell networks was identified. By using micro-contact printing and self-assembled monolayer technologies, two types of
in vitro
bone cell networks were constructed: open-ended linear chains and looped hexagonal networks with precisely controlled intercellular distances. Intracellular calcium responses of the cells were recorded and analysed when a single cell in the network was mechanically stimulated by nano-indentation. The looped cell network was shown to be more efficient than the linear pattern in transferring calcium signals from cell to cell. This phenomenon was further examined by pathway-inhibition studies. Intercellular calcium wave propagation was significantly impeded when extracellular adenosine triphosphate (ATP) in the medium was hydrolysed. Chemical uncoupling of gap junctions, however, did not significantly decrease the transferred distance of the calcium wave in the cell networks. Thus, it is extracellular ATP diffusion, rather than molecular transport through gap junctions, that dominantly mediates the transmission of mechanically elicited intercellular calcium waves in bone cells. The inhibition studies also demonstrated that the mechanical stimulation-induced calcium responses required extracellular calcium influx, whereas the ATP-elicited calcium wave relied on calcium release from the calcium store of the endoplasmic reticulum.
Prediction and parametric analysis of thermal profiles within heated human skin using the boundary element method
Authors: Ng E. Y. K. , Tan H. M. , Ooi E. H.
Published: January 2010

In this paper, an axisymmetric model of the human skin is developed to simulate the steady-state temperature distribution during contact with a hot solid. Simulations are carried out using the boundary element method. This study seeks to investigate the feasibility of using the boundary element method in the studies of burn. A sensitivity analysis is carried out to examine the effects of various parameters on the temperature distribution inside the skin during burn. Furthermore, a statistical analysis based on the Taguchi method is performed to determine the combination of factors that produce the desired outcome (least increase in temperature). In order to validate the accuracy of the numerical scheme, results obtained using the boundary element method are compared with the solutions obtained using the more established finite-element method.
Novel early response genes in osteoblasts exposed to dynamic fluid flow
Authors: Shivaram Giridhar M. , Kim Chi Hyun , Batra Nikhil N. , Yang Wuchen , Harris Stephen E. , Jacobs Christopher R.
Published: January 2010

Cyclic mechanical loads applied to the skeleton from habitual physical activity result in increased bone formation. These loads lead to dynamic pressure gradients and oscillatory flow of bone interstitial fluid, which, in turn, exposes cells resident in the bony matrix to oscillatory fluid shear stress. Dynamic fluid flow has previously been shown to be a potent anabolic stimulus for cultured osteoblasts. In this study, we used cDNA microarrays to examine early phase, broad-spectrum gene expression in MC3T3-E1 osteoblasts in response to physical stimulation. RNA was harvested at 30 min and 1 h post-stimulation. RNA was used for microarray hybridization as well as subsequent reverse transcription polymerase chain reaction (RT-PCR) validation of expression levels for selected genes. Microarray results were analysed by both functional and expression profile clustering. We identified a small number of genes at both the 30 min and 1 h timepoints that were either upregulated or downregulated with flow compared to no-flow control by twofold or more. From the group of genes upregulated at 30 min, we selected nine for RT-PCR confirmation. All were found to be upregulated by at least twofold. We identify a novel set of early response genes potentially involved in mediating the anabolic response of MC3T3 osteoblasts to flow, and provide functional groupings of these genes that may shed light on the relevant mechanosensory pathways involved.
Strain rate sensitivity of skin tissue under thermomechanical loading
Authors: Zhou B. , Xu F. , Chen C. Q. , Lu T. J.
Published: January 2010

There have been limited studies addressing the thermally dependent mechanical properties of skin tissue, although this can contribute to a variety of medical applications. To address this, an experimental study on the tensile behaviour of pig skin tissue under different thermal loading conditions and different mechanical stretching rates was performed. The results indicate that there is a significant variation among skin tensile behaviours under different temperatures and loading rates, which is correlated with dermal collagen denaturation. The Ogden model was used to summarize the effect of the strain rate and the temperature upon the measured constitutive response through two parameters (
α
and
μ
). These results can be used in future models to improve clinical thermal treatments for skin tissue.
Multi-scale heat and mass transfer modelling of cell and tissue cryopreservation
Authors: Xu Feng , Moon Sangjun , Zhang Xiaohui , Shao Lei , Song Young Seok , Demirci Utkan
Published: January 2010

Cells and tissues undergo complex physical processes during cryopreservation. Understanding the underlying physical phenomena is critical to improve current cryopreservation methods and to develop new techniques. Here, we describe multi-scale approaches for modelling cell and tissue cryopreservation including heat transfer at macroscale level, crystallization, cell volume change and mass transport across cell membranes at microscale level. These multi-scale approaches allow us to study cell and tissue cryopreservation.
Darwin's legacy: the forms, function and sexual diversity of flowers
Authors: Barrett Spencer C. H.
Published: January 2010

Charles Darwin studied floral biology for over 40 years and wrote three major books on plant reproduction. These works have provided the conceptual foundation for understanding floral adaptations that promote cross-fertilization and the mechanisms responsible for evolutionary transitions in reproductive systems. Many of Darwin's insights, gained from careful observations and experiments on diverse angiosperm species, remain remarkably durable today and have stimulated much current research on floral function and the evolution of mating systems. Here I review Darwin's seminal contributions to reproductive biology and provide an overview of the current status of research on several of the main topics to which he devoted considerable effort, including the consequences to fitness of cross- versus self-fertilization, the evolution and function of stylar polymorphisms, the adaptive significance of heteranthery, the origins of dioecy and related gender polymorphisms, and the transition from animal pollination to wind pollination. Post-Darwinian perspectives on floral function now recognize the importance of pollen dispersal and male outcrossed siring success in shaping floral adaptation. This has helped to link work on pollination biology and mating systems, two subfields of reproductive biology that remained largely isolated during much of the twentieth century despite Darwin's efforts towards integration.
A duplicate gene rooting of seed plants and the phylogenetic position of flowering plants
Authors: Mathews Sarah , Clements Mark D. , Beilstein Mark A.
Published: January 2010

Flowering plants represent the most significant branch in the tree of land plants, with respect to the number of extant species, their impact on the shaping of modern ecosystems and their economic importance. However, unlike so many persistent phylogenetic problems that have yielded to insights from DNA sequence data, the mystery surrounding the origin of angiosperms has deepened with the advent and advance of molecular systematics. Strong statistical support for competing hypotheses and recent novel trees from molecular data suggest that the accuracy of current molecular trees requires further testing. Analyses of phytochrome amino acids using a duplicate gene-rooting approach yield trees that unite cycads and angiosperms in a clade that is sister to a clade in whichGingkoand Cupressophyta are successive sister taxa to gnetophytes plus Pinaceae. Application of a cycads + angiosperms backbone constraint in analyses of a morphological dataset yields better resolved trees than do analyses in which extant gymnosperms are forced to be monophyletic. The results have implications both for our assessment of uncertainty in trees from sequence data and for our use of molecular constraints as a way to integrate insights from morphological and molecular evidence.
Defining the limits of flowers: the challenge of distinguishing between the evolutionary products of simple versus compound strobili
Authors: Rudall Paula J. , Bateman Richard M.
Published: January 2010

Recent phylogenetic reconstructions suggest that axially condensed flower-like structures evolved iteratively in seed plants from either simple or compound strobili. The simple-strobilus model of flower evolution, widely applied to the angiosperm flower, interprets the inflorescence as a compound strobilus. The conifer cone and the gnetalean ‘flower’ are commonly interpreted as having evolved from a compound strobilus by extreme condensation and (at least in the case of male conifer cones) elimination of some structures present in the presumed ancestral compound strobilus. These two hypotheses have profoundly different implications for reconstructing the evolution of developmental genetic mechanisms in seed plants. If different flower-like structures evolved independently, there should intuitively be little commonality of patterning genes. However, reproductive units of some early-divergent angiosperms, including the extant genusTrithuria(Hydatellaceae) and the extinct genusArchaefructus(Archaefructaceae), apparently combine features considered typical of flowers and inflorescences. We re-evaluate several disparate strands of comparative data to explore whether flower-like structures could have arisen by co-option of flower-expressed patterning genes into independently evolved condensed inflorescences, orvice versa. We discuss the evolution of the inflorescence in both gymnosperms and angiosperms, emphasising the roles of heterotopy in dictating gender expression and heterochrony in permitting internodal compression.
On ‘various contrivances’: pollination, phylogeny and flower form in the Solanaceae
Authors: Knapp Sandra
Published: January 2010

Members of the euasterid angiosperm family Solanaceae have been characterized as remarkably diverse in terms of flower morphology and pollinator type. In order to test the relative contribution of phylogeny to the pattern of distribution of floral characters related to pollination, flower form and pollinators have been mapped onto a molecular phylogeny of the family. Bilateral flower symmetry (zygomorphy) is prevalent in the basal grades of the family, and more derived clades have flowers that are largely radially symmetric, with some parallel evolution of floral bilateralism. Pollinator types (‘syndromes’) are extremely homoplastic in the family, but members of subfamily Solanoideae are exceptional in being largely bee pollinated. Pollinator relationships in those genera where they have been investigated more fully are not as specific as flower morphology and the classical pollinator syndrome models might suggest, and more detailed studies in some particularly variable genera, such asIochromaandNicotiana, are key to understanding the role of pollinators in floral evolution and adaptive radiation in the family. More studies of pollinators in the field are a priority.
Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot
Authors: Phillips Ryan D. , Hopper Stephen D. , Dixon Kingsley W.
Published: January 2010

The Southwest Australian Biodiversity Hotspot contains an exceptionally diverse flora on an ancient, low-relief but edaphically diverse landscape. Since European colonization, the primary threat to the flora has been habitat clearance, though climate change is an impending threat. Here, we review (i) the ecology of nectarivores and biotic pollination systems in the region, (ii) the evidence that trends in pollination strategies are a consequence of characteristics of the landscape, and (iii) based on these discussions, provide predictions to be tested on the impacts of environmental change on pollination systems. The flora of southwestern Australia has an exceptionally high level of vertebrate pollination, providing the advantage of highly mobile, generalist pollinators. Nectarivorous invertebrates are primarily generalist foragers, though an increasing number of colletid bees are being recognized as being specialized at the level of plant family or more rarely genus. While generalist pollination strategies dominate among insect-pollinated plants, there are some cases of extreme specialization, most notably the multiple evolutions of sexual deception in the Orchidaceae. Preliminary data suggest that bird pollination confers an advantage of greater pollen movement and may represent a mechanism for minimizing inbreeding in naturally fragmented populations. The effects of future environmental change are predicted to result from a combination of the resilience of pollination guilds and changes in their foraging and dispersal behaviour.
Speciation genes in the genus
Petunia
Authors: Venail Julien , Dell'Olivo Alexandre , Kuhlemeier Cris
Published: January 2010

A major innovation in angiosperms is the recruitment of animal pollinators as a means to enhance the efficiency and specificity of pollen transfer. The implementation of this reproductive strategy involved the rapid and presumably coordinated evolution of multiple floral traits. A major question concerns the molecular identity of the genetic polymorphisms that specify the phenotypic differences between distinct pollination syndromes. Here, we report on our work with
Petunia
, an attractive model system for quantitative plant genetics and genomics. From interspecific crosses, we obtained F2 plants that differed in the length of the floral tube or the size of the limb. We used these plants to study the behaviour of the hawkmoth pollinator,
Manduca sexta
. Plants with larger limbs were preferentially visited, consistent with the notion that flower size affects visibility under low light conditions. The moths also displayed an innate preference for shorter tubes. However, in those cases that flowers with long tubes were chosen, the animals fed for equal time. Thus, the perception of tube length may help the moths, early on, to avoid those plants that are more difficult to handle.
The pollination niche and its role in the diversification and maintenance of the southern African flora
Authors: Johnson Steven D.
Published: January 2010

The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems.
Diversity and evolution of floral structure among early diverging lineages in the Ericales
Authors: Schönenberger Jürg , von Balthazar Maria , Sytsma Kenneth J.
Published: January 2010

This is a combination of review and original data on floral structure and diversity in the two earliest diverging lineages of the Ericales, i.e. the balsaminoids, comprising Balsaminaceae, Marcgraviaceae and Tetrameristaceae, and the polemonioids, comprising Fouquieriaceae and Polemoniaceae. Each clade is strongly supported in molecular studies, while structural synapomorphies have largely been lacking. For the balsaminoid families, we compare floral morphology, anatomy and histology among selected taxa and find that the entire clade is strongly supported by the shared presence of nectariferous tissue in the floral periphery, thread-like structures on anthers, truncate stigmas, secretion in the ovary, as well as mucilage cells, raphides and tannins in floral tissues. A possible sister group relationship between Balsaminaceae and Tetrameristaceae is supported by the shared presence of post-genital fusion of filaments and ovary and a star-shaped stylar canal. For polemonioids, we document unexpected diversity of floral features in Polemoniaceae, partly providing structural links to Fouquieriaceae. Features include cochlear and quincuncial corolla aestivation, connective protrusions, ventrifixed anthers and nectariferous tissue in the base of the ovary. In addition, we outline future directions for research on floral structure in the Ericales and briefly discuss the general importance of structural studies for our understanding of plant phylogeny and evolution.
Tumorigenicity of the miR-17-92 cluster distilled: Figure 1.
Authors: van Haaften Gijs , Agami Reuven
Published: January 2010

The miR-17-92 gene cluster, with its six different mature microRNAs (miRNAs), has an established oncogenic function. However, the oncogenic contribution of each individual miRNA in the cluster has not been assigned. Two studies published in the December 15, 2009, issue of Genes & Development by Mu and colleagues (pp. 2806–2811) and Olive and colleagues (pp. 2839–2849) dissected the miR-17-92 cluster to its individual miRNA components and identified their relative contributions to oncogenic transformation in mouse model systems.