bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatic tumors: Magnetization transfer MR imaging with gadolinium enhancement
Authors: Onaya Hiroaki , Yoshioka Hiroshi , Itai Yuji , Niitsu Mamoru , Anno Izumi , Okumura Toshiyuki
Published: March 2007

Thirty patients with 15 hepatocellular carcinomas, 10 metastases, four hemangiomas, and one cholangiocarcinoma underwent magnetic resonance imaging at 1.5 T with T1‐weighted, T2‐ weighted spin‐echo (SE) images, gradient‐echo (GRE) magnetization transfer (MT) images, and gadolinium‐enhanced T1‐weighted SE and MT‐ GRE images. The MT effect and lesion‐liver contrast‐to‐noise ratio (C/N) were calculated and visual assessment (qualitative analysis) performed for unenhanced and enhanced MT‐GRE images and enhanced Tl‐weighted SE images. The C/N values for hepatic adenocarcinomas (seven metastases and one cholangiocarcinoma) and hemangiomas were larger for enhanced MT‐GRE images (adenocarcinoma, 8.4 ± 2.3 [P < 0.01); hemangioma, 24 ± 2.1 [P < 0.05]) than for enhanced GRE images (5.0 ± 1.9 and 18 ± 2.7, respectively).

These enhancing tumors had the highest scores in the qualitative analysis. Enhanced MT‐GRE images showed no advantage for depiction of hepatocellular carcinomas relative to the other images.
Cardiac‐gated MR angiography of pulsatile flow: K‐space strategies
Authors: Franck Anders , Selby Katharine , van Tyen Rem , Nordell Bo , Saloner David
Published: March 2007

Signal strength in time‐of‐flight magnetic resonance (MR) anglograpny of pulsatile flow is modulated by the time‐varying intraluminal magnetization strength. The specific appearance of MR angiographlc images therefore depends on the relationship of different phase‐encoding steps to the pulsatile flow waveform. Cardiac‐phase gating can be applied with phase‐encoding reordering to acquire different regions of k‐space during the desired phases of the cardiac cycle. The authors have developed a simulation program for evaluating the merits of different encoding strategies for pulsatile flow. The model was validated with phantom studies. High signal intensity relative to that in conventional MR anglographic studies can be attained with strategies that impose relatively small penalties in total acquisition time.
Fast three‐dimensional time‐of‐flight MR angiography of the intracranial vasculature
Authors: Talagala S. Lalith , Jungreis Charles A. , Kanal Emanuel , Meyers Steven P. , Foo Thomas K. F. , Rubin Richard A. , Applegate Gregory R.
Published: March 2007

Magnetic resonance angiography is most commonly performed with the three‐dimensional (3D) time‐of‐flight (TOP) technique. As currently practiced, this requires long image acquisition times (5–10 minutes). The authors show that the acquisition time of 3D TOP images can be reduced to less than 1 minute by using a very short TR (<10msec). Under normal flow conditions, the major vessels of the circle of Willis were consistently well demonstrated on these fast 3D TOP images. Signal saturation was observed in studies of patients with abnormal blood flow. In those cases, it was demonstrated that serial acquisition of fast 3D TOP data during and after contrast agent administration could be used to overcome the saturation effects. Time‐resolved fast 3D TOP imaging during and after contrast agent administration can also provide qualitative assessment of flow and may depict other features that cannot be observed in TOP studies with long imaging times.
Tracking of cyclic motion with phase‐contrast cine MR velocity data
Authors: Pelc Norbert J. , Drangova Maria , Pelc Lorie R. , Zhu Yudong , Noll Douglas C. , Bowman Brett S. , Herfkens Robert J.
Published: March 2007

A method of computing trajectories of objects by using velocity data, particularly as acquired with phase‐contrast magnetic resonance (MR) imaging, is presented. Starting from a specified location at one time point, the method recursively estimates the trajectory. The effects of measurement noise and eddy current‐induced velocity offsets are analyzed. When the motion is periodic, trajectories can be computed by integrating in both the forward and backward temporal directions, and a linear combination of these trajectories minimizes the effect of velocity offsets and maximizes the precision of the combined trajectory. For representative acquisition parameters and signal‐to‐ noise ratios, the limitations due to measurement noise are acceptable. In a phantom with reciprocal rotation, the measured and true trajectories agreed to within 3.3%. Sample trajectory estimates of human myocardial regions are encouraging.
Biopsy needles and devices: Assessment of ferromagnetism and artifacts during exposure to a 1.5‐T MR system
Authors: Moscatel Marleigh A. , Shellock Frank G. , Morisoli Stacy M.
Published: March 2007

Forty‐eight biopsy devices (needles, stylets, guide wires, biopsy guns, etc) were evaluated for ferro‐magnetism (n=48) and artifacts (n=43) in a 1.5‐T magnetic resonance (MR) system, with previously described techniques. Forty‐five of the 48 devices were found to be ferromagnetic. Artifacts varied, depending on the type and size of the component material(s) of the device. Most of the commercially available biopsy devices are not useful for MR imaging‐guided biopsy procedures because of the presence of ferromagnetism and associated artifacts.
Single breath‐hold volumetric imaging of the heart using magnetization‐prepared 3‐dimensional segmented echo planar imaging
Authors: Wielopolski Piotr A. , Manning Warren J. , Edelman Robert R.
Published: March 2007

We show the feasibility of single breath‐hold volumetric imaging of the heart using a three‐dimensional (3D) segmented echo planar Imaging (EPI) pulse sequence. Fifteen healthy subjects were evaluated using three magnetization preparation schemes: (a) a driven equilibrium T2‐weighted preparation for bright blood and dark myocardium; (b) a STEAM magnetization preparation for dark blood; and (c) fat suppression for coronary artery Imaging. An interleaved EPI trajectory encoding six echoes per Interleave with a 1090 Hz/pixel readout bandwidth was used to collect a 126 × 256 matrix in 22 heartbeats with data acquisition windows per cardiac cycle of 71–285 msec for 8–32 sections. Multiplanar reconstructions could be used if thin (1–3 mm) sections were acquired. Breath‐hold volumetric imaging with 3D segmented EPI holds promise for rapid volumetric evaluation of cardiac anatomy.
Variablemangle uniform signal excitation (vuse) for threel dimensional time‐of‐flight MR angiography
Authors: Priatna Agus , Paschal Cynthia B.
Published: March 2007

A spatially asymmetric RF pulse that improves the uniformity of blood signal intensity and vascular contrast in three‐dimensional (3D) MR angiorpgphy [MRA] is presented. The pulse, called variable‐angle uniform signal excitation (VUSE), was designed to provide uniform signal response and improved contrast for blood flowing through a 3D imagine volume during a FLASH sequence. The VUSE excitation proffle was optimized on the bash of the number of pulses seen by the blood, which varied with the velocity of through‐plane flow, repetition time, and slab thickness with the maximum flip angle at the flow udt constrained at 90°. The theoretical results show that the optimal RF pulse gives more uniformity for flow signal than does a linear ramp excitation proffle or a Gaussian pulse combined with a presaturation pulse. After truncation and ffltering of the VUSE pulse in the time domain, the general shape of the VUSE RF excitation profile is maintained. but the maximum flip angle is reduced. The arteries of the neck in a healthy volunteer were imaged with the VUSE pulse, a constant flip angle (flat) pulse, and a linear ramp pulse in flow‐compensated 3D MRA requences. The WSE pulse produced the most uniform signal as evidenced by the lowest relative dispersion of signal along the left vertebral artery (18.0 versus 26.4 to 23.6 for the other studies). F‐distribution tests also showed that the signal distribution obtained with the VUSE pulse in a 3D FLASH sequence was statistically different from that for the flat and the linear ramp pulses.
Partial volume effects in volume localized phased‐array proton spectroscopy of the temporal lobe
Authors: Strauss Wayne L. , Tsuruda Jay S. , Richards Todd L.
Published: March 2007

MRS techniques can aide in confirming the location of seizure foci in temporal lobe epilepsy. N‐acetyl aspartate (NAA). creatine plus phosphocreatine. choline‐containing compounds, and lactate arc most often the clinically relevant metabolites in these studies. We examined the importance of partial volume effects from tissue heterogeneity in temporal lobe spectroscopy on the metabolite ratios. Our study shows that localized spectroscopy, using three different voxel slzes. centered on the anterior body of the hippocampus. produces significantly different values for the NAA to the creatine ratio. The spectroscopy was performed at 1.5 T wing the PRESS pulse sequence and a phased‐array coil system specifically designed for the temporal lobe. The data exhibits a clear trend of increasing NM to creatine ratios with increasing voxel size. This trend demonstrates that partial volume effects can contribute to variation of NAA to creatine ratios in healthy subjects.
Artifacts in functional magnetic resonance imaging from gaseous oxygen
Authors: Bates Sandra , Yetkin Zerrin , Jesmanowicz Andre , Hyde James S. , Bandettini Peter A. , Estkowski Lloyd , Haughton Victor M.
Published: March 2007

Unexpectedly large fluctuations in signal intensity wen identified in the functional MRI (FMRI) of normal subjects breathing pure oxygen intermittently. To test the hypothesis that the signal changes were due to fluctuating concentrations of gaseous (paramagnetic) oxygen in the magnetic field, echo planar gradient echo images were acquired of a phantom contiguous to an oxygen mask through which pure oxygen was administered intermittently via plastic tubing. As a control, room air was administered intermittently or oxygen continuously in the same experimental protocol. Signal intensity changes of up to 60% temporally correlated with the administration of oxygen were produced in the phantom. In functional images prepared from the echo planar images, the signal intensity changes resulted in artifacts especially at interfaces in the phantom. The intermittent administration of pure oxygen during acquisition of data for FMRI may produce signal intensity changes that simulate or obscure function.
Comparison of t2 relaxation in blood, brain, and ferritin
Authors: Brooks Rodney A. , Vymazal Josef , Baumgarner Charles D. , Tran Vu , Bulte Jeff W. M.
Published: March 2007

T2 was measured in samples of human blood and monkey brain over a field range of 0.02–1.5 Tesla, with variable interecho times, and was compared with previous data on ferritin solutions (taken with the same apparatus). 1/T2 in deoxygenated blood increased quadratically with field strength, as noted previously, but in brain gray matter the increase was linear, as also was the case in ferritin solution. In both deoxygenated blood and gray matter, 1/T2 increased with interecho time, but appeared to level off at times around 50 msec, as expected from the theory of diffusion through magnetic gradients. Diffusion times estimated by using the chemical exchange approximation were 3.4 msec for deoxygenated blood and 5.7 msec for the globus pallidus. The quadratic field dependence in blood is consistent with this same theory, but the linear dependence in brain tissue and in ferritin solutions remains unexplained.
Csf‐suppressed t2‐weighted threel‐dimensional mp‐rage MR imaging
Authors: Epstein Frederick H. , Mugler John P. , Cail Wayne S. , Brookeman James R.
Published: March 2007

Fluid‐attenuated inversion recovery (FLAIR) is a pulse sequence used for acquiring T2‐weighted images of the brain and spine in which the normally high signal intensity of CSF is greatly attenuated. The CSF‐sup pressed T2‐weighted contrast of this technique may be more sensitive to a variety of disorders than that of conventional Tz‐weighted imaging. The primary disadvantage associated with conventional spin‐echo implementations of FLAIR is the relatively limited anatomic coverage that can be achieved in a reasonable imaging time. We developed and optimized a three‐dimensional magnetization‐prepared rapid gradient‐echo (3D MP‐RAGE) pulse sequence that combines CSF‐suppressed T2‐weighted contrast similar to exleting FLAIR techniques with anatomic coverage characteristic of 3D imaging. A preliminary evaluation of the new sequence was performed by imaging healthy volunteers and patients with multiple sclerosis.
Clearance of gadolinium chelates by hemodialysis: An in vitro study
Authors: Choyke Peter L. , Girton Mary E. , Frank Joseph A. , Vaughan Ellen M. , Austin Howard A.
Published: March 2007

Although the gadolinium (Gd)‐chelates currently approved for clinical use in the United States are considered “readily dialyzable,” the actual clearance rates have not been published. The purpose of this study was to establish in vitro dialysis clearance rates of Gd‐chelates to develop rational strategies for removing the agents with dialysis. Three agents, Gd‐diethylenetriaminopentaacetic acid (Gd‐DTPA), Gd‐HP‐DO3A and Gd‐DTPA‐BMA were diluted separately in plasma and saline and were dialyzed by using a clinical dialyzer unit with a commercially available capillary filter at rates of 0‐300 cc/min. Predialyzer and postdialyzer concentrations were determined by inductively coupled atomic emission photometry. Urea and creatinine clearance rates also were determined.

The clearance rate for Gd‐chelates were considerably lower than that of urea and cnatinine, which are generally considered benchmarks of dialysis efficiency. At 300 cc/min flow rates, the clearances were (clearance in cubic centimeters per minute with 95% con5dence interval): Gd‐DTPA‐74 cc/min (68‐80 cc/ a) S‐HP‐DO3A 67 cc/min (63‐71cc/min); and Gd‐ DTPA‐BMA 67 cc/min (63‐7lcc/min). In comparison, urea and creatinine were 180 cc/min (178‐181 cc/ mh) and 142 cc/& (124131 cc/min). respectively. There was no difference between clearance rates of Gd‐chelates in saline and plasma. implying there was no protein binding. By using a first order kinetic model of dialysis time, more than 12.2 to 14.7 hours of dialysis would be necessary to remove 97% of the injected dose of Gd‐chelate. In conclusion, Gd‐chelates are dialyzable and 97% elimination is predicted after 12‐14.7 hours of dialysis, depending on the chelate used. Consequently, Gd‐based contrast agents can be used in dialysis patients without modification to most maintenance dialysis schedules.
Phased‐Array Magnetic Resonance Imaging of the Carotid Artery Bifurcation: Preliminary Results in Healthy Volunteers and a Patient with Aherosclerotic Disease
Authors: Yuan Chun , Murakami James W. , Hayes Cecil E. , Tsuruda Jay S. , Hatsukami Thomas S. , Wildy Kathryn S. , Ferguson Marina S. , Strandness D. Eugene
Published: March 2007

A high resolution MR Imaging technique using a amtom designed flexible phased‐array surface coil was developed to examine the wall of the carotid artery bifuraction in vivo. The phaecd‐array consisted of two overlapping coils which increased the image signal‐to‐noise ratio at the depth of the carotid artery by approximately 70%, relative to a similarly sized single loop coil. The imaging protocol included a 2D T1‐weighted (TIW) spin‐echo scan and cardiac gated T2‐weighted and proton density‐weighted (PDW) fast Spin‐echo (FSE) scans. Images where obtained of six healthy volunteers and of one patient with known atherosclerotic dirreaw several days before carotid endartuectomy. On TIW and PDW images of the healthy volunteers. the carotid arterial wall appeared to be comprised of two concentric rings; a high signal inner ring and a lower signal outer ring. The MR images of the patient revealed a calcified carotid bifurcation plaque which was confirmed during surgery. The endarterectomy specimen WM imaged in vitro with MR and then sectioned histologically for correlation with the patients in vivo images. Our preliminary findings indicate that a high resolution technique may provide a noninvasive technique to study atherosclerosis of the carotid bifurcation.
A velocity correlation method for measuring vascular compliance using MR imaging
Authors: Urchuk Stephen N. , Plewes Donald B.
Published: March 2007

A method for estimating vascular compliance using MR velocity imaging is presented. The technique combines an analysis of pulse propagation, based on spatially averaged equations of continuity and momentum, together with phase‐contrast velocity measurements to estimate the compliance from a correlation of second‐order spatial and temporal velocity derivatives. The technique can be applied in the presence of reflected flow waves and uses velocity data acquired throughout the entire cardiac cycle. The accuracy of the technique was assessed in distensible vessel phantoms spanning a physiological range of compliance through a comparison with compliance estimates obtained using high‐resolution MR imaging and pressure transducers. The mean error of all measurements was found to be 0.04 ±0.02% per mm Hg, with the relative errors ranging from 1.2% to 46%. Error was found to decrease as the temporal sampling rate and/or image plane separation were increased. This suggests that an accurate hemodynamic evaluation of a vessel's elastic properties is feasible with MR velocity imaging techniques.
Plow quantitation with echo‐planar phase‐contrast velocity mapping: In vitro and in vivo evaluation
Authors: Debatin Jorg F. , Leung Daniel A. , Wildermuth Simon , Botnar Rene , Felblinger Jacques , McKinnon Graeme C.
Published: March 2007

We present a multishot echo‐planar imaging (EPI) phase‐contrast implementation for flow quantitation. The measurement accuracy of this technique was evaluated in vitro and in vivo. A gated eight‐shot EPI phase‐contrast sequence (TR/TE = 16/7.4, 45° flip angle), with a flow‐phase interval of 32 msec and an in‐plane resolution of 2× 2 mm was initially evaluated in a pulsatile flow phantom. Subsequently, EPI phase‐contrast flow measurements of the ascending and descending aorta, obtained in 10 volunteers, were compared with flow volume data acquired with a conventional cine phase‐contrast sequence (TR/TE = 24/7, 45° flip angle, 48‐msec flow‐phase interval, 2 × 1 mm in‐plane resolution). Comparisons between flow measurements were made using data obtained with the flow probe and cine phase contrast as the standard of reference for in vitro and in vivo measurements, respectively. EPI phase‐contrast sequences reduced data acquisition times tenfold compared with cine phase‐contrast sequences. EPI phase‐contrast flow measurements correlated were with phantom flow (r = 0.98, slope = 1.1) as well as with aortic cine phase‐contrast flow volume determinations (r = 0.98). A 95% confidence interval of measurement differences between echo‐planar and cine phase‐contrast imaging, ranging from 2.0 to ‐ 1058 mL/min was computed. Ultrafast phase‐contrast flow measurements are possible. Multishot EPI phase‐contrast imaging provides high measurement accuracy in pulsatile vessels while keeping the image acquisition interval short enough to be accomplished in a comfortable breath‐hold.
Comparison of phantom and computer‐simulated MR images of flow in a convergent geometry: Implications for improved two‐dimensional MR angiography
Authors: Siegel John M. , Oshinski John N. , Pettigrew Roderic I. , Ku David N.
Published: March 2007

The signal loss that occurs in regions of disturbed flow significantly decreases the clinical usefulness of MR angiography in the imaging of diseased arteries. This signal loss is most often attributed to turbulent flow; but on a typical MR angiogram, the signal is lost in the nonturbulent upstream region of the stenosis as well as in the turbulent downstream region. In the current study we used a flow phantom with a forward‐facing step geometry to model the upstream region. The flow upstream of the step was convergent, which created high levels of convective acceleration. This region of the flow field contributes to signal loss at the constriction, leading to overestimation of the area of stenosis reduction. A computer program was designed to simulate the image artifacts that would be caused by this geometry in two‐dimensional time‐of‐flight MR angiography. Simulated images were compared with actual phantom images and the flow artifacts were highly correlated. The computer simulation was then used to test the effects of different orders of motion compensation and of fewer pixels per diameter, as would be present in MR angiograms of small arteries. The results indicated that the computational simulation of flow artifacts upstream of the stenosis provides an important tool in the design of optimal imaging sequences for the reduction of signal loss.
Dynamic contrast‐enhanced MR imaging evaluation of osteosarcoma response to neoadjuvant chemotherapy
Authors: Reddick Wilburn E. , Bhargava Ravi , Taylor June S. , Meyer William H. , Fletcher Barry D.
Published: March 2007

Assessment of osteosarcoma response to neoadjuvant chemotherapy has prognostic implications, but conventional imaging techniques have been unable to provide an accurate quantitative measure of tumor response. We developed an analysis of dynamic contrast‐enhanced MR imaging (DEMRI) to render an image of dynamic vector magnitudes (DVM) and to summarize the result in a quantitative parameter, mean DVM for the lesion (μDVM). We compared the (μDVM from the examination before surgery with histologic results from an en bloc resection of the tumor in 19 cases. The final μDVM value provided an accurate (89.5%) measure of tumor necrosis in osteosarcoma. Further, we analyzed the findings in 17 patients with osteosarcoma who completed three DEMRI examinations during the course of therapy. Tumors with higher μDVM values at presentation had greater decreases in the parameter over the course of therapy. These results are consistent with the distribution of DVM values in these lesions serving as an indicator of tumor perfusion and a possible surrogate variable for drug delivery.
Mr image‐guided control of cryosurgery
Authors: Pease Grant R. , Wong Sam T. S. , Roos Mark S. , Rubinsky Boris
Published: March 2007

Cryoablation has recently become a useful procedure for the treatment of prostatic and hepatic tumors, primarily because of advances in the ability to monitor visually the freezing process with ultrasound. Success of the procedure depends in large part on how well the ice front can be positioned to destroy pathologic tissue, while sparing healthy tissue. This study describes a cryogen delivery system that can be used in conjunction with magnetic resonance (MR) image‐guided cryoablation, and an automatic control system that uses MR image guidance in a feedback loop to control the ice front trajectory. Edge‐detected MR images are used to determine the current ice front location at each time interval, providing feedback to an automatic control system that adjusts the flow of cryogen to the cryoprobe. Numerical simulations and experimental results demonstrate that an ice front with cylindrical symmetry can be accurately controlled using this MR image‐guided feedback control scheme.
A variable‐ force microvascular clip
Authors: Dujovny Manuel , Perlin Alfred , Kossovsky Nir
Published: March 2007

An easily adjustable, variable‐ force microvascular clip is described. This clip is superior to other clips currently available because it is essentially three clips in one. Its advantages are that it can reduce the amount of table area needed to store clips during surgery and it offers the surgeon greater flexibility in the selection of clips with different closing forces. This clip was developed by modifying the segments of a basic alpha‐ type clip, designing a computer program to analyze the force contributions made by each segment of the clip, constructing several clips with different blade lengths, and testing them in a microvascular surgery research program. The clip we have developed is easy to use, reduces clutter on the instrument table, and offers the surgeon a wide choice of closing forces with a minimal number of clips.
The hand table for pediatric microsurgery
Authors: Matloub Hani S. , Trevisani Thomas P. , Sanger James R.
Published: March 2007

The technique using the hand table for positioning of infants for microsurgical procedures of the lower extremity is presented. With this technique, the surgeon and assistant are able to sit directly opposite each other with their arms in stable resting position.
Arterial anastomoses and autogenous interposition grafts in growing rats
Authors: Stoll Amos W. , Chater Norman , Phillips Mark
Published: March 2007

The fate of arterial interposition grafts in growing rats was investigated. The interrupted‐ and continuous‐suture techniques were compared to see which allowed for better expansion of the anastomosis. We found that a graft enlarges in proportion to the growth of the parent vessel, that in end‐to‐end anastomosis the interrupted suture technique allowed for better expansion of the anastomosis (but not in the end‐to‐side model), and that the continous suture technique was associated with a higher rate of false aneurysm formation.
Empty perineurial tube graft used to repair a digital nerve: A first case report
Authors: Restrepo Yolanda , Merle Michel , Petry Didier , Michon Jacques
Published: March 2007

The first clinical application using the medial cutaneous nerve as an empty perineurial tube graft in a patient with sensory deficit in the index finger is described. The technique used is described and results are evaluated both qualitatively and quantitatively. Nerve regeneration is obtained through the graft.
Effect of sympathectomy on microvascular anastomosis in the rat
Authors: Hweidi Sobhi A. , Lee Sun , Wolf Paul
Published: March 2007

An operative technique of lumbar sympathectomy in the rat is described. Two days following either sympathectomy or sham‐sympathectomy, bilateral femoral arterial anastomoses were performed by a 1‐year trained microsurgeon (S.A.H.) and patency was assessed by preoperative and postoperative (30 minutes, daily) operative invasive and noninvasive techniques using an electromagnetic flow meter (for immediate postoperative) and Doppler, respectively. Of 112 rats, three and one postoperative deaths occurred within 24 hours following abdominal surgery in each group, respectively. Of 105 anastomoses in the sympathectomy group, 103 (98%) and 101 (96%) had patent anastomoses 30 minutes and 14 days postoperatively, respectively, while 109 of the sham‐sympathectomy group had 105 (96%) and 103 (94%) patencies at the same period of the observation, respectively. Thus the sympathectomy did not much alter the microvascular patency rate in the rat. It appears therefore that the meticulous microvascular anastomosis cannot be replaced by lumbar sympathectomy in the rat.
Debridement and replantation of the spleen with microsurgical restoration of blood flow
Authors: Monsivais J. , Seaber Anthony , Urbaniak James R.
Published: March 2007

Splenectomy continues to be the most commonly chosen method of management of traumatic injury to the spleen. However, patients of all age groups who have undergone splenectomy have significant impairment of immune functions as demonstrated by decreased production of IGM, tufsin, and properdin. This immune deficiency has been clinically manifested by an increased incidence of postsplenectomy pneumonia and sepsis which is reduced but not eliminated by the use of pneumococcal vaccine and/or prophylactic antibiotics. This paper presents the results of a study of the feasibility of repair and replantation of injured spleens using microsurgical techniques. Twenty cats had their spleens removed, finger‐fractured, and debrided. The cats were then assigned to one of four groups. Group I had the entire spleen replanted but only 75% of the parenchyma revascularized. Group II had 75% of the parenchyma revascularized and replanted. Group III had 50% revascularized and replanted, and Group IV 25% revascularized and replanted. Patency of the anastomoses was assessed by postoperative arteriography. Restoration of reticuloendothelial (filter) function was assessed by the use of technetium sulphur colloid scans which showed preservation of reticuloendothelial function of the revascularized segments but absence of function in nonrevascularized segments which had been replanted. Histologic examination of replanted spleens harvested at 8 weeks showed normal architecture of red and white pulp in all areas that had been revascularized. However, in those spleens where the entire spleen had been replanted but only partially revascularized, the nonrevascularized segments were degenerated and atrophic.
A microsurgical method for experimental kidney denervation
Authors: Kullendorff Carl Magnus
Published: March 2007

A successful microsurgical method for denervation of the kidney in the rat is presented. Unilateral kidney denervation was performed in eight animals. Ten sham‐operated animals were used as controls. Under ether anaesthesia, the kidney vessels on one side were exposed. The peritoneum above the vessels was incised and the area was stained with 1% toluidine blue solution. The nerves were identified. With microsurgical technique, the nerves were carefully separated from the vessels and resected. Tissue specimens from both kidneys in all animals were removed and analysed for norepinephrine content. There was no normal difference between the kidneys in the shamoperated rats. About 1 week after denervation, the norepinephrine concentration in the denervated kidney showed a 95% reduction, indicating a complete denervation. The described microsurgical procedure was a rapid, simple, and reproducible method for kidney denervation in the rat.
Intimal tears and their relationship to longterm patency in the rat femoral artery
Authors: Glover Michael G. , Seaber Anthony V. , Urbaniak James R.
Published: March 2007

The prognostic importance of arterial intimal tears is not certain in the long term. We have developed a model to evaluate pure intimal damage in the absence of other soft tissue injury or arterial anastomoses to study the effect of isolated traumatic arterial intimal tears. Groups of ten rats each were examined at 1, 2, 4, 8, and 48 weeks and were shown to have no incidence of thrombosis of the femoral artery following traumatic intimal tears. Histologically, there was persistence of medial disorganization and smooth muscle hypertrophy up to 48 weeks. We feel that intimal lesions alone do not predispose a rat femoral artery to thrombosis but might do so in the presence of significant soft tissue injury or an arterial anastomosis.
New method for cardiac transplantation
Authors: Umeki Yasuhiro , Weinrib Harry P. , MacLeod Cathel A. , Economou Steven G. , Gebel Howard M.
Published: March 2007

Rat cardiac transplantation into the femoral region has several advantages compared to cardiac transplantation into the peritoneal cavity. These advantages include increased speed, decreased hypothermia of the recipient, and easier‐access palpation. However, there is a major discrepancy in the size of the donor and recipient vessels. The donor aorta is two to three times larger than the recipient's femoral artery and thus could be a contraindication to the transplant. To circumvent this problem, we anastomosed the donor's aorta with the recipient's femoral artery by an end‐in‐end technique whereas the donor's pulmonary artery was anastomosed by conventional end‐to‐end technique with the recipient's femoral vein. The excess wall of the donor's vessel was plicated on a slant for each anastomosis. Our results compare favorably to those of techniques established previously. We suggest that this new method of cardiac transplantation will be of great value in the study of immunological events involved in graft rejection.
Mural repair following obliteration of aneurysms: II. Pathomorphology of treated aneurysms
Authors: Young Paul H. , Fischer Vernon W. , Young Paul A. , Guity Afrassiab , El Fiki Mohammed
Published: March 2007

Mural vascular repair following experimental and clinical aneurysm obliteration was studied using the scanning electron microscope and standard histological techniques. Two of the more frequently utilized clinical obliteration techniques, clipping and coagulation, were examined. A chronological description of the mural reparative process reveals that clipping is superior to coagulation in most instances, that coagulation results in satisfactory obliteration of the aneurysmal orifice only in very selected circumstances, and that a combination of coagulation and clipping may be the best overall obliteration technique.
Long‐term studies of pancreas allotransplantation in experimental diabetes mellitus
Authors: Lee Sun , Scott Michael H. , Yancey Diane , Allen Jennifer , Chang Eil Sung , Chisari Francis , Moossa A. R.
Published: March 2007

Pancreaticoduodenal (PD) allografts (Brown Noway‐alloxan‐diabetic rats, n = 190) were treated with cyclosporin A (Cy‐A) 10 mg/kg/daily and compared with nondiabetics with Cy‐A treatment (n = 55), diabetics (n = 50), and diabetics with Cy‐A treatment (n = 45). Body weight, blood sugar, blood insulin, blood urea nitrogen (BUN), and creatinine were monitored periodically; there were marked elevations of BUN and creatinine levels, indicating probable nephrotoxicity of Cy‐A at this dosage. Some islet cell atrophy in the PD allografts was noted at the conclusion of the study. With respect to the immunosuppressive effect of Cy‐A in alloxan diabetic rats, Brown Norway PD transplants into Lewis rats were successful and free of rejection for as long as 15 months post‐transplantation. The body weight of these PD transplanted rats, however, never approached values representative of the nondiabetic rats. In our experience, the PD allograft model is acceptable in the clinical situation, particularly in children if the microsurgical technique is mastered and if the Cy‐A regimen is used in combination with other immunosuppressant(s).
Microlaryngology: An update on its modern use in laryngology‐malignant early and advanced glottic carcinoma
Authors: Hickscol Julius N.
Published: March 2007

The modern use of microlaryngology is improving the diagnosis and treatment of early and advanced glottic laryngeal lesions. Microlaryngology is a microscopic laryngoscopic technique that is used to carry out laryngeal tumor evaluation and biopsy. For early, small, and advanced laryngeal glottic lesions, a microscope is used to view the larynx through a laryngoscope that is placed transorally. This is a precise method of microsurgery to biopsy and stage early and advanced malignant tumors of the glottic area of the larynx. Recent advances using microscopic visualization, microsurgical instruments, and a CO2 laser as a tool to control bleeding and to debulk the tumors of patients with advanced lesions enable the operating surgeon to visualize accurately the involvement by tumor of the overlying mucosa or the underlying muscles and cartilages in this area and sometimes to restore the airway. Precise knowledge regarding the microscopic locational extent of these tumors is important in developing appropriate options for treatment of early and advanced malignant neoplasms of the glottic area of the larynx in order to cure the disease and save the voice of the patient.
Advances in otologic microsurgery
Authors: Eby Thomas L.
Published: March 2007

Recent advances in otologic microsurgery have brought progress in the improvement of hearing impairment, alleviation of vertigo, and removal of skull base tumors. Refinement of stapedectomy techniques, use of new biocompatible prostheses, and other advances promise improved results with established otologic procedures. In addition, implantable hearing aids and cochlear implants will increasingly improve hearing in patients who previously could not be helped. The surgical methods for vestibular nerve section continue to be refined to help the surgeon and minimize risk to the patient. The challenging new field of skull base surgery has been opened through the combined efforts of otologists and other specialists. The recent advances in these fields are reviewed.
The quiet embryo hypothesis: Molecular characteristics favoring viability
Authors: Baumann Christoph G. , Morris Dermot G. , Sreenan Joseph M. , Leese Henry J.
Published: March 2007

It has been proposed that the viability of early mammalian embryos is associated with a metabolism that is “quiet” rather than “active” (Leese HJ, 2002:BioEssays 24:845–849). The data on which this hypothesis was based were largely drawn from measurements on the depletion and appearance of amino acids from the culture medium. Data on the de novo synthesis of protein in in vivo‐ and in vitro‐derived bovine embryos, as determined from the flux of radiolabeled methionine, have provided further support of the hypothesis and are interpreted to provide a new set of testable propositions that could illuminate the molecular basis of the quiet metabolism phenotype. The propositions are based on the premise that the extent of DNA damage, and the RNA and protein content of the immature oocyte, are key factors in determining whether the zygote progresses to the blastocyst stage. We propose that stochastic events and environmental stresses determine whether the condition of the genome, transcriptome, and proteome of the zygote will support development. Several molecular components are identified that may determine the viability of a zygote, and we speculate that the cellular response to unfavorable events or excessive DNA damage may be the premature activation of the embryonic genome and of apoptosis. Mol. Reprod. Dev. 74: 1345–1353, 2007. © 2007 Wiley‐Liss, Inc.
A shared promoter region suggests a common ancestor for the human VCX/Y, SPANX, and CSAG gene families and the murine CYPT family
Authors: Hansen Martin A. , Nielsen John E. , Retelska Dorota , Larsen Niels , Leffers Henrik
Published: March 2007

Many testis‐specific genes from the sex chromosomes are subject to rapid evolution, which can make it difficult to identify murine genes in the human genome. The murine CYPT gene family includes 15 members, but orthologs were undetectable in the human genome. However, using refined homology search, sequences corresponding to the shared promoter region of the CYPT family were identified at 39 loci. Most loci were located immediately upstream of genes belonging to the VCX/Y, SPANX, or CSAG gene families. Sequence comparison of the loci revealed a conserved CYPT promoter‐like (CPL) element featuring TATA and CCAAT boxes. The expression of members of the three families harboring the CPL resembled the murine expression of the CYPT family, with weak expression in late pachytene spermatocytes and predominant expression in spermatids, but some genes were also weakly expressed in somatic cells and in other germ cell types. The genomic regions harboring the gene families were rich in direct and inverted segmental duplications (SD), which may facilitate gene conversion and rapid evolution. The conserved CPL and the common expression profiles suggest that the human VCX/Y, SPANX, and CSAG2 gene families together with the murine SPANX gene and the CYPT family may share a common ancestor. Finally, we present evidence that VCX/Y and SPANX may be paralogs with a similar protein structure consisting of C terminal acidic repeats of variable lengths. Mol. Reprod. Dev. 75: 219–229, 2008. © 2007 Wiley‐Liss, Inc.
Time course of meiotic progression after transferring primary spermatocyte into ooplasm at different stages
Authors: Nan Chang‐Long , OuYang Ying‐Chun , Zhao Zhen‐Jun , Jiang Yan , Lei Zi‐Li , Huang Jun‐Cheng , Song Xiang‐Fen , Sun Qing‐Yuan , Chen Da‐Yuan
Published: March 2007

This study attempted to investigate the time course of meiotic progression after transferring primary spermatocyte (PS) into ooplasm at different maturing stages. In present experiments, PSs were introduced into maturing ooplasts or oocytes by electrofusion. Higher fusion rate was obtained by phytohemagglutinin (PHA) agglutination than by perivitelline space (PVS) insertion. When the ooplasms prepared at 0, 2, 5, and 8.5 hr of in vitro maturation (IVM) were used as recipients and PSs were used as donors, the reconstructed cells extruded the first polar body (PB1) approximately 8.5, 7, 5.5, and 3 hr after electrofusion, respectively. Especially, when ooplasm cultured for 8.5 hr in vitro after GV removal was fused with PS, the PB1 was emitted 7–11 hr after electrofusion. Additionally, the PB1 extrusions of GV and pro‐MI oocytes fertilized with PSs were 2.5 hr earlier than control oocytes. The results suggest that (1) PSs undergo the first meiosis in different time courses when introduced into ooplasm at different maturing stages; (2) GV material plays an important role in determining the timing of PB1 extrusion; and (3) first meiotic division of GV and pro‐MI oocytes can be accelerated by introducing PS. Mol. Reprod. Dev. 74: 1072–1080, 2007. © 2007 Wiley‐Liss, Inc.
Selenium improves the developmental ability and reduces the apoptosis in porcine parthenotes
Authors: Uhm Sang Jun , Gupta Mukesh Kumar , Yang Ji Hoon , Lee Sung‐Ho , Lee Hoon Taek
Published: March 2007

Selenium is an essential trace element in conventional tissue culture media to guarantee adequate biosynthesis of selenoprotein in cellular antioxidant system to protect the cells from oxidative damage and apoptosis. This study investigated the effect of selenium, in the form of sodium selenite (SS), on developmental ability and quality of in vitro produced porcine parthenotes. For this, parthenogenetic presumptive diploid zygotes were produced by electroactivation and cultured in the absence or presence of SS at different concentrations (0, 2.5, 25, 250 ng/ml) in a serum‐free defined culture medium supplemented with polyvinyl alcohol (PVA) or bovine serum albumin (BSA). Results showed that, development rate of 2–4 cell stage parthenotes to blastocyst and their cell number was increased while TUNEL index was decreased, in a dose‐dependent manner, when SS was supplemented to NCSU23 + PVA. Interestingly, the blastocyst rate and their quality approached to those cultured in NCSU23 + BSA (P < 0.05), thereby suggesting PVA + 25 ng/ml SS to be a partial replacement of BSA. In the presence of PVA, supplementation of SS at a concentration of 25 ng/ml did not improve the cleavage rate of in vitro matured oocytes but there was significant improvement in the blastocyst rate (45.4 ± 8.8% vs. 12.7 ± 4.8%), total nuclei number (42.1 ± 3.5 vs. 31.3 ± 2.9) and inner cell mass (ICM) rate (29.4 ± 1.5% vs. 21.3 ± 1.2%) and decrease in TUNEL index (5.6 ± 0.5 vs. 12.9 ± 1.3) compared to nonsupplemented controls. The SS supplementation also decreased the BAX:BCL‐xL transcript ratio, increased the expression of ERK1/2 and glutathione peroxidase (GPX) and reduced the level of Caspase 3 proteins (P < 0.05). These data thus suggest that SS improves the development rate and quality of porcine parthenotes by preventing oxidative damage and apoptosis. Mol. Reprod. Dev. 74: 1386–1394, 2007. © 2007 Wiley‐Liss, Inc.
Volume‐selective Water‐suppressed Proton Spectra of Human Brain and Muscle in vivo
Authors: Bárány M. , Venkatasubramanian P. N.
Published: March 2007

Volume‐selective water‐suppressed proton spectra were recorded from live human brain and muscle at 1.5 T by combining a stimulated echo acquisition mode pulse sequence for localization and two saturation pulses for water suppression (Frahm et al., SMRM Abstracts, 1987). Metabolite signals were observed in voxels of size 4–64 cm3. Signals from —CH3 and β‐CH2 of N‐acetylaspartate, N—CH3 and N—CH2 of phosphocreatine/creatine, —N(CH3)3 of choline and inositol protons were visible in the brain spectra from normal subjects. Differences in metabolite levels were observed between gray and white matters of brain from their water‐suppressed spectra. Peaks from N—CH3 of phosphocreatine/creatine and —+N(CH3)3 of choline and carnitine were present in normal muscle spectra along with several resonances from fatty acyl chains.
Forebrain ischemia studied using magnetic resonance imaging and spectroscopy
Authors: Saunders John K. , Smith Ian C. P. , Mactavish James C. , Rydzy Marek , Peeling James , Sutherland Eric , Lesiuk Howard , Sutherland Garnette R.
Published: March 2007

A combination of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) has been used to follow the time course of changes resulting from forebrain ischemia in the rat. The 31P MRS demonstrates that the level of high energy metabolites decreases significantly during the 10 min ischemic period but returns to normal after 1 h of reperfusion. MRI shows no change after 1 h of reperfusion but significant changes in the striatum after 24 h and in the hippocampus after 48 h. These changes correlate well with histopathology. Diabetic rats have shown the effect of hyperglycemia in accentuation of ischemic and post ischemic pH changes. Conversely, diabetic rats maintained severely hypoglycemic with insulin showed little variation in pH during or following the ischemic insult. The results emphasize the importance of both MRS and MRI in following the temporal profile and distribution of ischemic neuronal injury.
Image directed proton spectroscopy of gerbil brain at 7 Tesla
Authors: Middleton D. A. , Glen S. , Reid D. G. , Hockings P. D. , Rose S. E. , Crozier S. , Roffman W. , Doddrell D. M. , Rothaul A. L. , Hunter A. J.
Published: March 2007

Image directed localized 1H NMR spectra were obtained at 7 T (300 MHz) from cubic volumes of less than 40 m̈L in the gerbil brain. Signals from cerebral metabolites commonly detected in other rodent species were easily assigned, and high resolution spectroscopy (360 MHz) of aqueous brain extracts assisted the tentative identification of partially overlapping resonances from lower concentration compounds like alanine, lysine, γ‐aminobutyrate, valine, leucine and isoleucine. Weak coupling at 7 T was manifest in the resolution of signals from the γ‐CH2 groups of glutamine and glutamate. Down‐field of water, signals assigned to purine nucleotides were conspicuous in the extract spectra, but localized spectra acquired routinely in vivo, using selective excitation and gradient crushing (SUBMERGE) for water suppression, exhibited little or no signal from purines. When localized in vivo spectra were acquired without water suppression, however, or using a low power binomial excitation sequence rather than SUBMERGE, a broad signal appeared at the resonant frequency of purine aromatic protons. NMR experiments on the nucleotide adenosine 5′‐monophosphate (AMP) in 90% glycerol/10% D2O solution demonstrated that pre‐irradiation of the water signal even for less than 100 ms attenuated the nucleotide signal appreciably. This implies that the soft pulses required for selective excitation of water in sequences such as SUBMERGE induce spin‐diffusion which eliminates or diminishes the signal from nucleotides in vivo.
Prenatal ultrasonic diagnosis of radial‐ray aplasia and renal anomalies (acro‐renal syndrome)
Authors: Meizner Israel , Bar‐Ziv Jacob , Barki Yehiel , Abeliovich Dvorah
Published: March 2007

Prenatal ultrasonic diagnosis of a rare case of radial ray aplasia and crossed renal ectopy is described in an affected sibling of a family where the father and his son suffer from this rare syndrome. The prenatal diagnosis enabled early pregnancy termination.
Antenatal diagnosis of a de novo paracentric inversion of chromosome 11
Authors: Grass Frank S. , Parke James C. , Hisley John C.
Published: March 2007

A de novo paracentric inversion of chromosome 11 identified through antenatal diagnosis is described along with long‐term follow‐up information on the child and discussion of reported experiences with de novo inversions.