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Fibrin polymerization involves thrombin-mediated exposure of knobs on one monomer that bind to holes available on another, leading to the formation of fibers. In silico evidence has suggested that the classical A:a knob-hole interaction is enhanced by surrounding residues not directly involved in the binding pocket of hole a, via noncovalent interactions with knob A. We assessed the importance of extended knob-hole interactions by performing biochemical, biophysical, and in silico modeling studies on recombinant human fibrinogen variants with mutations at residues responsible for the extended interactions. Three single fibrinogen variants, γD297N, γE323Q, and γK356Q, and a triple variant γDEK (γD297N/γE323Q/γK356Q) were produced in a CHO (Chinese Hamster Ovary) cell expression system. Longitudinal protofibril growth probed by atomic force microscopy was disrupted for γD297N and enhanced for the γK356Q mutation. Initial polymerization rates were reduced for all variants in turbidimetric studies. Laser scanning confocal microscopy showed that γDEK and γE323Q produced denser clots, whereas γD297N and γK356Q were similar to wild type. Scanning electron microscopy and light scattering studies showed that fiber thickness and protofibril packing of the fibers were reduced for all variants. Clot viscoelastic analysis showed that only γDEK was more readily deformable. In silico modeling suggested that most variants displayed only slip-bond dissociation kinetics compared with biphasic catch-slip kinetics characteristics of wild type. These data provide new evidence for the role of extended interactions in supporting the classical knob-hole bonds involving catch-slip behavior in fibrin formation, clot structure, and clot mechanics.

Fibrin polymerization involves thrombin-mediated exposure of knobs on one monomer that bind to holes available on another, leading to the formation of fibers. In silico evidence has suggested that the classical A:a knob-hole interaction is enhanced by surrounding residues not directly involved in the binding pocket of hole a, via noncovalent interactions with knob A. We assessed the importance of extended knob-hole interactions by performing biochemical, biophysical, and in silico modeling studies on recombinant human fibrinogen variants with mutations at residues responsible for the extended interactions. Three single fibrinogen variants, γD297N, γE323Q, and γK356Q, and a triple variant γDEK (γD297N/γE323Q/γK356Q) were produced in a CHO (Chinese Hamster Ovary) cell expression system. Longitudinal protofibril growth probed by atomic force microscopy was disrupted for γD297N and enhanced for the γK356Q mutation. Initial polymerization rates were reduced for all variants in turbidimetric studies. Laser scanning confocal microscopy showed that γDEK and γE323Q produced denser clots, whereas γD297N and γK356Q were similar to wild type. Scanning electron microscopy and light scattering studies showed that fiber thickness and protofibril packing of the fibers were reduced for all variants. Clot viscoelastic analysis showed that only γDEK was more readily deformable. In silico modeling suggested that most variants displayed only slip-bond dissociation kinetics compared with biphasic catch-slip kinetics characteristics of wild type. These data provide new evidence for the role of extended interactions in supporting the classical knob-hole bonds involving catch-slip behavior in fibrin formation, clot structure, and clot mechanics.

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Solution-processable electronic devices are highly desirable due to their low cost and compatibility with flexible substrates. However, they are often challenging to fabricate due to the hydrophobic nature of the surfaces of the constituent layers. Here, we use a protein solution to modify the surface properties and to improve the wettability of the fluoropolymer dielectric Cytop. The engineered hydrophilic surface is successfully incorporated in bottom-gate solution-deposited organic field-effect transistors (OFETs) and hybrid organic–inorganic trihalide perovskite field-effect transistors (HTP-FETs) fabricated on flexible substrates. Our analysis of the density of trapping states at the semiconductor–dielectric interface suggests that the increase in the trap density as a result of the chemical treatment is minimal. As a result, the devices exhibit good charge carrier mobilities, near-zero threshold voltages, and low electrical hysteresis.

•Mice expressing nonpolymerizable fibrinogen are protected against venous thrombosis and have suppressed arterial thrombosis.•Selective prevention of fibrin polymerization had minimal influence on hemostasis.

The aim of this study was to present rates of claims, causes of error, percentage of cases resulting in a judgment, and average payments made by radiologists in chest-related malpractice cases in a survey of 8265 radiologists.

Abstract The objective of this study was to evaluate the operation of the portable X-ray machine in relation to examinations ordered by the Emergency Department at the University of Medicine and Dentistry of New Jersey, as well as to identify any bottlenecks hindering the performance of the aforementioned system. To do so, the activity of the portable X-ray was monitored in the period from 8 June 2004 to 24 June 2004, as well as from 6 July 2004 to 12 July 2004, yielding 11 days of data and 116 individual X-ray examinations. During observation times was noted for various checkpoints in the procedure. Using the data gathered, the average input, output, processing times, and variance were calculated. In turn, these values were used to calculate the response times for the Ordering Phase (5.502 min), traveling (2.483 min), Examination Phase (4.453 min), returning (3.855 min), Order Processing Phase (2.962 min), and the Development Phase (3.437 min). These phases were combined for a total of 22.721 min from the time the examination was placed to the time the X-ray films were uploaded to the PACS computer network. Based on these calculations, the Ordering Phase was determined to be the single largest bottleneck in the portable X-ray system. The Examination Phase also represented the second largest bottleneck for a combined total of 44% of the total response time.

Abstract Recent and rapid increases in the utilization of diagnostic imaging have not been matched by concomitant additions to the supply of radiologists and radiology technologists. One proposal to alleviate an expected worsening of this emerging workforce crisis is to create a new job category, the radiology assistant (RA), encompassing a roster of enhanced capabilities that would allow the radiologists to divest themselves of some of their non-interpretative duties with respect to the performance of imaging tests. Through the collaborative efforts of the American College of Radiology and the American Society of Radiology Technologists a nationally recognized, baccalaureate-level curriculum has been designed for the training of RAs. A centerpiece of the curriculum is instruction in fluoroscopy. However, examinations of the GI tract by fluoroscopy are rapidly declining in frequency, raising doubt about the enhanced value an RA would bring to a radiology practice in the near future and worries about encroachment on the range of radiologists’ responsibilities over the long term.

Transitioning to a filmless department is no easy task, especially at a large academic medical center. At the University of Medicine and Dentistry of New Jersey--New Jersey Medical School, a phased modality integration schedule was implemented to allow the technical and clinical staff to gradually absorb all of the changes to workflow. One-on-one training sessions were designed to prepare radiologists and referring clinicians to access and navigate the in-house picture archiving and communication system (PACS) workstations as well as to view images over the Internet via the PACS Web server. An interdepartmental steering committee was formed to plan deployment of the in-house workstations. A planning committee met on a weekly basis to outline placement of workstations within the Radiology Department, and to redesign the reading room. A user group was created to discuss specific user problems. Of particular interest was the challenge of outfitting a dozen conference rooms with projection systems capable of displaying radiologic images. We distinguished between regular and working conferences. At regular conferences only a few cases are reviewed over the course of an hour and only after the diagnosis has been made at a PACS workstation. In contrast, the surgical and medical intensive care units conduct daily working conferences. At those sessions the images of 20 to 30 patients are reviewed, many of them for the first time, and for each case a definitive diagnosis is expected. During the implementation process, a range of issues came up that limited access of certain studies to radiologists and referring clinicians alike. Even after the initial PACS installation, many studies went unread because of a lack of worklists. Other problems included image ordering for head computed tomography and magnetic resonance imaging. A few of our modalities were not DICOM compliant and needed image capture devices in order to be integrated with the PACS. To our dismay, this was also true of one of our modalities that was supposed to be DICOM compliant. These problems, and the solutions we discovered, are discussed in this paper.

As a result of prior studies elucidating the potential complications associated with the use of central venous access lines, the Food and Drug Administration and the manufacturers themselves have published guidelines and warnings outlining these dangers and describing the safest insertion techniques. We will attempt to determine whether this improved education has altered the number and type of complications, comparing the results from different types of hospitals, among the various medical services and among operators with varying degrees of experience. This is a prospective analysis of all central venous pressure (CVP) and Swanz-Ganz catheters (SGCs) inserted between July 1, 1995, and February 30, 1996, at a regional Veteran's Affairs hospital and an inner city university medical center. Three hundred seventy-five inpatients underwent 417 new percutaneous venous catheter placements while in the medical or surgical intensive care units or in the general care wards. A portable chest radiograph was obtained immediately after each procedure, and the position of the catheter and any associated complications were recorded, initially by the radiology resident in the emergency suite and subsequently as confirmed by a chest radiology attending. CVP lines were considered malpositioned when the tip was not located in the superior vena cava, and SGCs were recorded as misplaced when the tip was not found within the main, left main, right main, or either lower lobe pulmonary artery within 2 cm of the cardiac border. For patients undergoing CVP line placement, the right atrium was the most frequent site of tip malposition with 38 of 69 total misplacements (55%), whereas for SGCs, 22 of 55 malplacements (40%) were too distal in a lower lobe pulmonary artery. Only 1 of 248 CVP lines resulted in a pneumothorax (PTX; 0.4%), whereas 6 of 169 SGC insertions caused a PTX (3.5%), a significant difference (P = 0.019). Five of 192 catheters (2.6%) placed via an internal jugular approach resulted in PTX, whereas only 2 of 150 subclavian cannulations (1.3%) caused this complication, revealing a trend, but not reaching statistical significance (P = 0.473). However, there was a significant decrease in the rate of catheter misplacements in the third part of the month compared with the first 20 days (35% versus 24%; P = 0.031), and the Veteran's Affairs hospital displayed a trend toward more complications for SGC insertions than the university hospital (47% versus 32%), but not for CVP lines. In general, individual medical and surgical services displayed a similar frequency of complications (29–38%), except for CVP lines inserted in the medical intensive care unit. Venous access catheter tip malpositions are very common in all settings, but easily recognized by radiography, whereas PTXs are unusual. In contrast to most older studies, PTXs are more frequently observed with internal jugular as opposed to subclavian cannulations and with SGCs rather than CVP lines. However, our data support prior studies that the right atrium and distal right lower lobe pulmonary artery are the most common sites for CVP and SGC misplacement, respectively, and that there is an improvement in success rates with increasing operator experience.

Custom has come to dictate an inadequate evaluation of the abdomen by allowing the kidney ureters and bladder study (KUB) to be deemed equivalent to a full study of the supine abdomen. The reason for this suboptimal approximation is related to architectural imperatives, traditional practice, and landmark studies favoring horizontal beam projections. Now, using the digital scout view in conjunction with contemporaneous computed tomography, the diagnostic importance of the uppermost abdomen, positioned beyond the superior limit of a KUB, can be demonstrated, and its sensitivity can be measured for the recognition of pneumoperitoneum. In large patients, a two-view supine abdominal series can overcome the neglect of the subdiaphragmatic region, improving our capability to recognize free air, even when its volume is less than 1 cc.

Two cases of esophageal intramural pseudodiverticulosis are presented. A brief review is made of previously published reports. This entity, first described in 1960, is still rarely diagnosed. Its etiology is still debatable. However, as more cases are published, it becomes more apparent that esophageal intramural pseudodiverticula can be found as part of a distinct syndrome with diffuse intramural pseudodiverticulosis, as originally described by Mendl, or localized in a limited extension of the esophagus as a reponse to esophageal obstruction.

Flattening of the infrahepatic inferior vena cava (IVC) on postcontrast computed tomographic (CT) scans has been reported as a sign of severe hypovolemia. The significance of this finding on unenhanced CT scans, however, has not been reported. We retro-spectively studied 60 consecutive outpatient abdominal CT scans in which both unenhanced and postcontrast sequences were performed. Flattening of the infrahepatic IVC on unenhanced CT images was noted in six patients (10%) without evidence of hypovolemia or extrinsic IVC compression. The degree of IVC fullness increased in 43 study patients overall (72%) after contrast administration. We propose several mechanisms for postcontrast IVC distention and conclude that a flattened infrahepatic IVC on unenhanced CT scans does not indicate hypovolemia in the absence of other suggestive clinical or CT findings.

Plain radiographic findings in appendicitis have been neglected somewhat since the advent of cross-sectional imaging studies. Nevertheless, a definitive diagnosis may be made with conventional radiography in selected cases. The most important finding is the recognition of an appendicolith, which, like the appendiceal lumen, may be located far from its expected position in the right lower quadrant. Air in the appendix is a normal finding, except when the lumen is dilated. Ancillary findings, such as cecal dilatation, are nonspecific. Recognition of appendiceal abscess depends upon demonstration of a mass and/or extraluminal air in the form of large lucencies or small bubbles.

The chest radiograph is the most common imaging examination and usually the first study in any evaluation of thoracic disease. It is often obtained upon initial presentation to the emergency department. Unfortunately, because of its two-dimensional nature and limited contrast sensitivity, certain regions, such as the mediastinum are particularly difficult to evaluate. A number of anatomic variants in that compartment can mimic significant pathology. The subject of this review is the range of normal patterns and common mediastinal anomalies, including those from the osseous, gastrointestinal, and vascular systems, as well as the supporting stromal tissue. We also consider postoperative modifications of the mediastinal contours.

Two cases of giant vascular malformation of the kidney demonstrated by computed tomography and angiography are presented. The vascular malformations form completely outside the kidney. They arise from the renal parenchyma, simulating renal cyst, and present as a renal pelvic mass causing hydronephrosis. The finding of a renal mass with a markedly and uniformly contrast enhancement demonstrated by computed tomography should suggest the possibility of a vascular malformation.

RATIONALE AND OBJECTIVES. The biological effects of iodinated contrast media were examined by using spermatogenesis in mouse testis as the experimental model.

No abstract.

Fast inversion recovery for myelin suppression is a new magnetic resonance sequence with the ability to increase gray‐white matter contrast. This can improve the definition of normal anatomical structures.

The article discusses the impact of the increase in the use of radiation doses on neoplasm incidence. It highlights that advances in computed tomography (CT) have led to the growth of CT applications in the field of medicine. According to several studies from both U.S. and foreign researchers, CT use and thyroid gland cancer are related. Thyroid cancer cases in the U.S. have increased by 4.3 percent annually since 1996.

Focuses on the challenges facing radiologists as manager of diagnostic imaging and its impact on the health care system in the U.S. as it seeks to reduce costly self-referral practices. Potential risk of malpractice by radiologists engendered by the modification of the computed tomography (CT) image protocol; Implications of a visually restrictive organ-specific CT; Consequences of the notion that every specialty requires access to imaging.

We report two cases of portal vein wall calcification demonstrated by CT. The clinical features of such patients are reviewed, and proposed etiologic mechanisms are discussed.

The operation of a radiology consultation service in an acute care teaching hospital is described. The radiologist acts as an active advisor in the structuring of diagnostic evaluations in three disease categories; biliary tract disease, nonemergency gastrointestinal tract bleeding, and abdominal mass. There was a 64% reduction in the time needed to establish a diagnosis and a 32% decrease in the number of studies for each patient on the consultation ward compared with a control group, which consisted of patients with similar clinical presentations. A formal partnership between clinician and radiologist serves two important functions in teaching hospitals. It can simultaneously expedite diagnostic evaluations and teach the best utilization of imaging examinations.(JAMA 1982;248:2152-2154)

On sonography, particulate echoes noted within the lumen of the renal pelvis indicate severe urinary infection (pyonephrosis). However, the significance of echoes noted within the bladder lumen during transvaginal sonography has not been previously evaluated. We assessed for the presence of mobile intraluminal echoes within the bladder in 50 consecutive women without symptoms of urinary infection who were referred for transvaginal sonography. Particulate echoes were noted within the bladder urine in 36 women (72%). Urinalysis was normal in six (75%) of eight women in whom urinary echoes were noted and who consented to provide a urine specimen. We conclude that particulate echoes within bladder urine noted during transvaginal sonography are normal and do not indicate the presence of urinary infection. This is probably because the relatively high frequency of trnasvaginal probes facilitates detection of normal particulate urinary constitutents which are not as readily discernible with lower-frequency transabdominal probes.

A case of gallbladder empyema is presented, which opacified initially on excretory urography and then on nephrotomography, mimicking a renal mass. Correct diagnosis was accomplished by angiography and ultrasound examination. With normal renal function gallbladder visualization on urography is indicative of a gallbladder abnormality.

The article focuses on the changes in reports implemented at the main teaching hospital of the New Jersey Medical School to improve interactions between radiologist, referrer and patient. The two most cited irritants in dictated reports involve the use of the phrase "clinical correlation suggested" and the tendency to recommend specific supplementary imaging. The establishment of verbal discussion as a regular component of the report process is explained including the surveillance of its implementation.

A response by Stephen R. Baker and Gauri S. Tilak to a letter to the editor about their article "CT Spurs Concern Over Thyroid Cancer" in the December 2006 issue is presented.