Safety and Effectiveness of a Bioabsorbable Steroid-Releasing Implant for the Paranasal Sinus Ostia: A Randomized Clinical Trial

Importance

Suboptimal outcomes of endoscopic sinus surgery (ESS) are often associated with restenosis and inflammation of frontal sinus ostia. Steroid-releasing sinus implants have been shown to maintain sinus patency by minimizing inflammation and scar tissue formation. An hourglass-shaped, bioabsorbable, steroid-releasing implant was developed to provide mechanical support and optimize drug delivery to paranasal sinus ostia.

Objective

To assess the safety and efficacy of the hourglass-shaped, bioabsorbable, steroid-releasing sinus implant in improving postoperative outcomes when placed in the frontal sinus ostia (FSO) following ESS in patients with chronic rhinosinusitis (CRS).

Design, Setting, and Participants

In a prospective, multicenter, randomized clinical trial using an intrapatient control design (ESS followed by implant placement within 1 FSO vs ESS alone on the contralateral side) 80 adult patients, with a mean (SD) age of 49.5 (13.4) years and consisting of 53 (66%) men and 27 (34%) women, were enrolled and underwent bilateral frontal sinusotomies with 1 frontal sinus randomized to receive a steroid-releasing implant. The study was carried out in 12 US centers between July 2015 and March 2016.

Interventions

A bioabsorbable steroid-releasing implant with hourglass shape containing 370 µg of mometasone furoate. All patients received standardized postoperative care.

Main Outcomes and Measures

The need for postoperative interventions, medical and surgical, in the FSO at day 30, as determined based on review of video endoscopic findings by an independent blinded surgeon. Also, endoscopic grading by the independent reviewer and clinical investigators at day 30 and day 90 and computed tomographic scan at day 90.

Results

The mean (SD) age of patients was 49.5 (13.4) years, 53 (66%) were men. Implants were successfully placed in all 80 randomized treatment sinuses. At day 30, steroid-releasing implants significantly reduced the need for postoperative interventions to 11.5% compared with 32.8% by surgery alone (mean difference, -21.3%; 95% CI, -35.1% to -7.6%), as assessed by the independent reviewer. Real-time endoscopic assessment by clinical investigators at day 30 demonstrated significant reduction in need for postoperative intervention (mean difference, -17.3%; 95% CI, -27.9% to -6.7%), significant reduction in inflammation score (mean difference, -12.3 mm; 95% CI, -18.3 to -6.4 mm), and significant reduction in rate of frontal restenosis or occlusion (mean difference, -22.7%; 95% CI, -33.5% to -11.9%) on treated compared with control sides. The results favoring the treatment sides were sustained through day 90: reduced need for postoperative interventions (mean difference, -11.7%; 95% CI, -21.0% to -2.4%) and reduction in restenosis and/or occlusion of the frontal ostium (mean difference, -17.4%; 95% CI, -28.6% to -6.1%). No implant-related adverse events were observed.

Conclusions and Relevance

The hourglass-shaped steroid-releasing sinus implant was safe and more effective in maintaining FSO patency and improving surgical outcomes compared with surgery alone in the setting where no other immediate postoperative corticosteroids were administered.

Trial Registration

ClinicalTrials.gov identifier: NCT02266810.

On Producing Random Responses

This paper has surveyed studies of response patterning in an attempt to illustrate the various ways in which this fact of behavior has been used in psychology. The view is expressed that response biasing takes on significance as an important dependent variable when we note that human Ss are unable to generate binary choices in a random sequence even when instructed to do so. Production of random sequences may be intimately related to processes of set and attention; success in generating responses randomly indicates ability to maintain an appropriate set for randomness. Techniques for measuring response patterning, or variability, were reviewed, and a new method was described. Data were presented to illustrate the difficulties encountered by students and psychiatric patients when instructed to generate a random sequence of binary choices. Almost nothing is known about the correlates of ability to maintain a set for randomness, yet there are marked individual differences in this ability. Generating random choices is basically a very non-stimulating task, so that differences in arousal may be of particular importance, when studying this particular kind of set.

Responsivity of Psychiatric Patients to Verbal Conditioning: “Success” and “Failure” Conditions and Pattern of Reinforced Trials

A sample of 64 psychiatric patients was used to study responsiveness to minimal social reinforcement by means of operant verbal conditioning procedures. As in previous work with college students the effects of two types of situational variation were studied: pattern of reinforced trials and examiner's evaluation of performance. Ss told TAT-like stories and on selected trials the use of emotional words was reinforced. Highly significant conditioning was found, indicating that psychiatric patients are responsive to minimal social reinforcement. Significant group differences were not found, however, for either the success-failure dimension of examiner evaluation of performance, or for reinforced vs extinction trials. The results for patients agree with those reported earlier for students only insofar as the initial conditioning is concerned. In general, patients show initial responsiveness to examiner reinforcement, but they are not readily influenced by situational variations occurring later in the session.

Motivational interviewing as a mechanism for change in men who batter: a randomized controlled trial

The present study reports on the potential effectiveness of motivational interviewing (MI) in changing the way batterers think about their violent behavior. Thirty-three domestic violence offenders who were court-mandated to treatment were randomly assigned to MI or a control condition before attending their first mandated treatment group. Consistent with predictions, the MI group demonstrated generally more improvement on stages of change subscales than the control group. Further, the MI group demonstrated a significantly greater decrease in the extent to which they blamed their violence on external factors. Current data indicate that MI has the potential to increase batterers' motivation to change, although validation trials with larger sample sizes and more refined measures are required.

Associations between anxiety and marital adjustment

Cognitive-behavioral theories of marital functioning and contextual models of close relationships highlight the importance of proximal affect states such as anxiety in couple functioning. Despite these assertions, research examining the role of state anxiety is lacking in the literature on intimate relationships. In this study, the authors examined state anxiety and marital adjustment in a sample of 45 couples. Hierarchical regression analyses indicated that husbands' Time 1 anxiety can predict their own and their wives' subsequent reports of marital adjustment. Wives' Time 1 anxiety did not predict their own or their husbands' subsequent reports of marital adjustment. In this study, the authors focused on the role of husband anxiety in marital adjustment and on implications for further study of the contextual model of close relationships.

A tool to assess homebound status

Although this specific instrument focuses solely on helping the home care nurse determine homebound status, this type of instrument can be developed for the other criteria used in assessing a client for Medicare-eligible home care services. For example, a similar instrument can be developed to assess whether a patient meets the criteria for part-time intermittent care or skilled care using the Medicare definitions as a guide to tool development. As we move into a time when there is more scrutiny of home care for compliance to Medicare regulations and increased productivity to assure cost effectiveness, instruments like this are essential for careful documentation that allows the agency to demonstrate accountability. In addition, home care agencies are expecting new home care nurses to know and be able to apply the Medicare regulations after a brief orientation. Instruments like this can shorten the orientation process and provide support for the home care nurse in the field.

A mentor-based laboratory management elective for residents

With the evolution of health care delivery systems, laboratories are being viewed as cost centers, and their value is being continually challenged. This requires pathologists to be adequately trained as leaders and managers. New training curricula for pathology residents have been developed, including combined didactic and mentor-based training. At the University of Utah, Salt Lake City, the combination of a large academic pathology department with a wholly owned commercial laboratory has allowed the development of a comprehensive 1-month didactic management course for senior residents. This course is designed to develop a broad-based foundation in laboratory management principles. The reinforcement of many of these principles, however, requires additional hands-on effort. We describe our first experience with this 1-month, theory based-teaching followed by a 3-month "real-world" experience based on a one-on-one mentor relationship between the director of laboratories and a senior resident, who assumed the role of the assistant director of laboratories.

Multiple forms of arginase are differentially expressed from a single locus in Neurospora crassa

The Neurospora crassa catabolic enzyme, arginase (L-arginine amidinohydrolase, EC 3.5.3.1), exists in multiple forms. Multiple forms of arginase are found in many vertebrates, but this is the only reported example in a microbial organism. The two major forms are structurally similar with subunit sizes of 36 and 41 kDa, respectively. The larger form is produced by mycelia growing in arginine-supplemented medium. Both forms are localized in the cytosol. The structural gene for arginase, aga, has been cloned and sequenced; it contains a 358-codon open reading frame with three in-frame ATGs at the amino terminus. Mutagenesis of these ATGs revealed that the first ATG initiates the 41-kDa protein and the third ATG initiates the 36-kDa protein. Mutation of the second ATG has no effect on translation. Northern analysis demonstrated that a 1.4-kilobase (kb) transcript is synthesized in minimal medium and both a 1.4- and 1.7-kb transcript are produced in arginine-supplemented medium. Primer extension identified the 5' ends of each transcript and demonstrated that the first and third ATG of the open reading frame are the initial AUGs of the 1.7- and 1. 4-kb mRNA, respectively. The results suggest that a basal promoter produces the 1.4-kb transcript and an arginine "activated" promoter is responsible for the 1.7-kb transcript. Tandem promoters are rare in eukaryotic organisms, and they often regulate developmental or tissue-specific gene expression. The possibility that arginase has a role in differentiation in N. crassa is being investigated.

Malignant transformation of recurrent respiratory papillomatosis associated with integrated human papillomavirus type 11 DNA and mutation of p53

Recurrent respiratory papillomatosis (RRP), usually confined to the nasopharynx, trachea, and larynx, occasionally can progress to extensive bronchopulmonary disease. Most cases of bronchopulmonary and laryngeal papillomatosis are cytologically benign and do not undergo malignant transformation; however, squamous cell carcinoma (SCC) can arise in RRP in the absence of known risk factors such as radiation and smoking. In this study, the authors investigated molecular genetic alterations occurring in a case of metastasizing SCC that arose in long-standing bronchopulmonary papillomatosis. Genomic DNA from tracheal papillomata, tracheobronchial papillomata, SCC of the lung, and a lymph node metastasis was extracted. The physical state of the human papillomavirus type 11 (HPV-11) DNA was investigated by two-dimensional gel electrophoresis. Molecular genetic alterations of the host genome were studied by direct sequencing of polymerase chain reaction-amplified gene fragments and restriction fragment length polymorphism (RFLP) analysis. Episomal and integrated forms of HPV-11 sequences were detected in histologically benign tumors, but only the integrated form of the viral DNA could be found in malignant tissue samples. Molecular genetic studies revealed that an allelic loss of the interferon-beta gene (IFNbeta-1) and an endogenous type of mutation of the p53 antioncogene were found only in the malignant lesions. Mutations were not observed in the ras, neu, or multiple tumor suppressor (MTS1/p16) genes in any specimens. The authors' data indicated that the p53 genetic mutation was associated with integration of HPV-11 in histologically malignant lesions. This association may promote a progressive genetic instability that can lead to the development and clonal expansion of malignant lesions in RRP.

Processing and function of a polyprotein precursor of two mitochondrial proteins in neurospora crassa

In Neurospora crassa, the mitochondrial arginine biosynthetic enzymes, N-acetylglutamate kinase (AGK) and N-acetyl-gamma-glutamyl-phosphate reductase (AGPR), are generated by processing of a 96-kDa cytosolic polyprotein precursor (pAGK-AGPR). The proximal kinase and distal reductase domains are separated by a short connector region. Substitutions of arginines at positions -2 and -3 upstream of the N terminus of the AGPR domain or replacement of threonine at position +3 in the mature AGPR domain revealed a second processing site at position -20. Substitution of arginine at position -22, in combination with changes at -2 and -3, prevented cleavage of the precursor and identified two proteolytic cleavage sites, Arg-Gly downward arrow Tyr-Leu-Thr at the N terminus of the AGPR domain and Arg-Gly-Tyr downward arrow Ser-Thr located 20 residues upstream. Inhibitors of metal-dependent peptidases blocked proteolytic cleavage at both sites. Amino acid residues required for proteolytic cleavage in the connector were identified, and processing was abolished by mutations changing these residues. The unprocessed AGK-AGPR fusion had both catalytic activities, including feedback inhibition of AGK, and complemented AGK-AGPR- mutants. These results indicate that cleavage of pAGK-AGPR is not required for functioning of these enzymes in the mitochondria.

Characterization of vacuolar arginine uptake and amino acid efflux in Neurospora crassa using cupric ion to permeabilize the plasma membrane

Treatment of Neurospora crassa mycelia with cupric ion has been shown to permeabilize the plasma and mitochondrial membranes. Permeabilized mycelia were shown to take up arginine into the vacuoles. Uptake was ATP-independent and appeared to be driven by an existing K+-gradient. The kinetic characteristics of the observed uptake were similar to those observed using vacuolar membrane vesicles: the Km for arginine uptake was found to be 4.2-4.5 mM. Permeabilized mycelia were used to study the regulation of arginine uptake into vacuoles. The results suggest that uptake is relatively indifferent to the contents of the vacuoles and is not affected by growth of mycelia in amino acid-supplemented medium. Efflux of arginine, lysine, and ornithine from vacuoles was also measured using mycelia permeabilized with cupric ion. Arginine release was shown to be specifically enhanced by cytosolic ornithine and/or increases in the vacuolar pool of arginine or ornithine. Lysine efflux was shown be indifferent to the presence of other amino acids. These observations emphasize the importance of vacuolar compartmentation in controlling arginine and ornithine metabolism and suggest that vacuolar compartmentation may play an important role in nitrogen homeostasis of filamentous fungi.

Natural killer-like T-cell lymphoma in the small intestine of a child without evidence of enteropathy

A previously healthy 6-year-old boy developed symptoms of small intestinal obstruction and was found to have a large intraabdominal mass. At laparotomy the mass involved the jejunum and adjacent mesenteric lymph nodes, requiring resection. Microscopic and immunohistochemical studies demonstrated a T-cell non-Hodgkin's lymphoma, confirmed by finding clonal T-cell receptor-beta and -gamma gene rearrangements by Southern blot analysis. The immunophenotype of this lymphoma-CD3+CD4-CD8-CD56+TIA-1+ beta F1(-)-suggests that the tumor cells are cytotoxic natural killer (NK)-like T cells, probably of CD3+CD4-CD8- intraepithelial cell origin. Examination of the adjacent and distal small intestinal mucosa failed to show any significant pathologic change. This case was unusual because intestinal lymphomas in children are usually of B-cell origin and most commonly have small noncleaved cell morphology. Childhood intestinal T-cell lymphomas have not been the focus of specific study but appear to be rare. In adults, intestinal T-cell lymphomas often arise in the background of gluten-sensitive enteropathy (celiac disease). In contrast, this child had peripheral T-cell lymphoma, with NK-like T-cell features, in the small intestine with no clinical or histologic evidence of enteropathy.

High jugular bulb and conductive hearing loss

A high jugular bulb is often discovered as an incidental finding that is asymptomatic. Conductive hearing loss in association with this anomaly may occur, but has been reported infrequently in the literature. We report five cases of high jugular bulb and associated conductive hearing loss. Mechanisms to explain the conductive hearing loss include contact of the jugular bulb with the tympanic membrane, interference with the ossicular chain, and obstruction of the round window niche. The operative findings, radiographic and audiometric data that support these mechanisms of conductive hearing loss are presented.

Acetylglutamate synthase from Neurospora crassa: structure and regulation of expression

A DNA clone which complemented an arg-14 mutation of Neurospora crassa was isolated by sib selection from a cosmid library (pMOcosX). Southern and restriction-fragment-length polymorphism (RFLP) analysis confirmed that the cloned DNA contained the arg-14 gene. The arg-14 gene was identified as the structural gene for acetylglutamate synthase by immunodepletion of enzyme activity with antibodies prepared against an arg-14 fusion protein and by the thermal instability of acetylglutamate synthase in a temperature-sensitive arg-14 mutant. The fungai acetylglutamate synthase has little sequence homology to its bacterial counterpart, unlike other arginine biosynthetic enzymes. Expression of the arg-14 gene is regulated by cross-pathway control similar to many amino acid biosynthetic genes. However, expression of acetylglutamate synthase occurs throughout the developmental growth cycle, unlike other arginine biosynthetic enzymes.

Clear plastic cups: a childhood choking hazard

The disposable plastic beverage cup is not usually regarded as hazardous to young children. Certain varieties of these products however, are manufactured from a brittle, clear plastic that easily cracks and fragments. While most conscientious parents keep their children safe from peanuts, balloons, and other known choking hazards, a child can surreptitiously bite a cup edge and aspirate the fragment. We report two cases of foreign body aspiration involving clear plastic cups that went undetected one of which remained 21 months following a negative rigid bronchoscopy. Diagnostic difficulties are related to the transparency and radiolucency of these objects. When suspicious of foreign body aspiration in children, otolaryngologists should inquire about the availability of clear plastic cups in the household and be mindful of the diagnostic pitfalls. Further investigations including CT scanning and repeat bronchoscopy may be helpful in cases of suspected missed foreign bodies. An educational campaign aimed at prevention and placement of product package warning labels should be established.

Descending thoracic aortomyoplasty: a technique for clinical application

BACKGROUND

Descending thoracic aortomyoplasty is a form of skeletal muscle-powered cardiac assistance. Its use in clinical settings has been limited by the ligation of intercostal arteries necessary to complete a circumferential wrap of the aorta with the latissimus dorsi.

METHODS

This study assessed the feasibility and the efficacy of aortomyoplasty constructed with a modified latissimus dorsi. A pericardial patch was attached to the latissimus dorsi and divided around the preserved intercostal arteries. Nine alpine goats (37 +/- 2 kg) underwent descending aortomyoplasty using this technique. All intercostal arteries were preserved. After a 6-week recovery period, the animals underwent a 6-week, incremental electrical conditioning program. After 90 postoperative days, animals were examined under anesthesia with the myostimulator on and off.

RESULTS

Aortomyoplasty activation resulted in augmentation of mean diastolic aortic pressure by 16.0 +/- 0.9 mm Hg (23%). Significant improvements in cardiac index (40%), stroke volume index (37%), left ventricular stroke work index (49%), and mean arterial pressure (19%) were noted. An intravascular sonographic probe placed in the descending aorta revealed circumferential compression of the aorta during counterpulsation. Mean cross-sectional aortic area was reduced by 51.8%, from 210.1 +/- 7.1 to 108.9 +/- 6.7 mm2 during aortomyoplasty activation (p < 0.05). Histologic analysis confirmed the long-term patency of intercostal arteries.

CONCLUSIONS

Descending aortomyoplasty, modified with an interposing patch of pericardium, effectively transfers skeletal muscle force across the aortic wall and assists cardiac function. This technique allows preservation of all aortic branches, and with this novel approach, the clinical utility of aortomyoplasty can now be explored.

The usefulness of transesophageal echocardiography in diagnosing cardiac contusions

OBJECTIVES

To assess the usefulness of transesophageal echocardiography in diagnosing cardiac contusions in patients with blunt trauma.

BACKGROUND

For more than a decade, noninvasive tests, including ECGs, cardiac enzymes, nuclear studies, and transthoracic echocardiography have been utilized in an attempt to identify trauma patients with cardiac injuries. These tests have been imperfect in identifying the patients at high risk for mortality.

METHODS

We retrospectively reviewed the charts in 22 patients with transesophageal echocardiographically diagnosed cardiac contusions noting age, race, sex, transthoracic echocardiographic examinations, study quality, and outcome. We also noted the Injury Severity Score, which is a measure of the severity of illness in trauma patients. Higher scores correlate more severe injury and higher mortality. We defined cardiac contusions as presence of wall motion abnormality, including either or both ventricles, in the absence of transmural myocardial infarction on ECG following nonpenetrating chest trauma.

RESULTS

Over a 30-month period, 81 transesophageal echocardiographic examinations were performed on trauma patients. Among this group, 22 patients were diagnosed as having cardiac contusions. There were 15 patients with right ventricular contusions, 7 patients with left ventricular contusions, and 2 patients with both ventricles involved. We compared this group with all ICU trauma patients admitted to the hospital during this time period. Overall, the contusion patients had an average Injury Severity Score of 27 and a mortality of 27% compared with the overall trauma group with an Injury Severity Score of 33 and a corresponding mortality of 9% (p < 0.001). Corresponding ECGs were nondiagnostic in 73% of patients with cardiac contusion. There were no complications related to the transesophageal examinations.

CONCLUSIONS

Transesophageal echocardiographically diagnosed cardiac contusion in trauma patients carries a high mortality rate. Transesophageal examinations are safe and provide excellent quality images where transthoracic examinations were inadequate. Right ventricular contusions are approximately twice as common as left ventricular contusions.

Marital interaction coding system: revision and empirical evaluation

Given the vast amount of codeable information in marital interactions, observational coding systems must emphasize particular classes of behavior. The most widely used marital coding scheme, the Marital Interaction Coding System (MICS), like many older behavioral coding systems, emphasizes verbal content over affect. Changes made to the MICS between versions III and IV are described; they were intended to increase the system's use of coded affect and to decrease autodependence in sequential analysis. We used an archival data set of 994 couples' videotaped conflict negotiations coded with the MICS. As intended, the MICS-IV, relative to the MICS-III, was found to have the advantage of capturing more non-verbal affect expressed during marital interactions, which resulted in stronger interactional contingencies (e.g. Wife Blame-->Husband Blame, Husband Facilitation-->Wife Facilitation). The MICS-IV also yielded significantly lower levels of spurious autodependence.

Transition in quality: from quality assurance to strategic quality management

The 1990s and beyond present formidable challenges to health-care providers, including clinical laboratories and pathology departments. However, numerous opportunities lie within these challenges. Discovering these opportunities and exploiting them will be critical success factors for future survival. Quality assurance, continuous quality improvement, and strategic and financial planning are all activities used to a varying extent by clinical laboratories. The cumulative potential benefits to an organization in which these activities are integrated can far exceed their sum as individual components. Coordinating these interdependent processes is the basis for managing strategically. The experience of one organization's efforts to plan and develop such a strategy is presented and discussed.

Reversible uridylylation of the Escherichia coli PII signal transduction protein regulates its ability to stimulate the dephosphorylation of the transcription factor nitrogen regulator I (NRI or NtrC)

We have reconstituted the signal transduction system responsible for the negative regulation of the transcription of the Escherichia coli glnA gene, encoding glutamine synthetase, by glutamine. This signal transduction system consists of four proteins: the transcription factor NRI (NtrC), which activates glnA transcription when it is phosphorylated, the kinase/phosphatase protein NRII (NtrB) that directly controls the extent of NRI phosphorylation, the PII signal transduction protein that controls the phosphatase activity of NRII, and the uridylyltransferase/uridylyl-removing (UTase/UR) enzyme that is regulated by glutamine and controls the activity of PII. In the reconstituted system, the removal of uridylyl groups from the PII protein, catalyzed by the UTase/UR protein in the presence of glutamine, resulted in the stimulation of NRI approximately P dephosphorylation. In contrast, the uridylylated form of the PII protein had no discernible effect on NRI phosphorylation. The uridylylation of the trimeric PII protein by the monomeric UTase/UR protein is a non-cooperative reaction in which the partially modified species accumulated and were readily observed. Partially modified PII trimers were partially active in stimulating the dephosphorylation of NRI approximately P. Thus, both the PII-UTase/UR and PII-NRII interactions display the continuous variability characteristic of rheostats as opposed to the binary variability characteristic of toggle switches.

Management of the thyroid isthmus in tracheostomy: a prospective and retrospective study

The thyroid isthmus is often encountered while a tracheostomy is being performed. This study details retrospective and prospective comparison of electrocautery division of the isthmus with older techniques. In this study, electrocautery division of the thyroid isthmus during tracheostomy is faster and as safe as other techniques with respect to blood loss, perioperative complications, and airway outcome.

Pseudoinfarction ECG pattern caused by diaphragmatic hernia uniquely resolved by transthoracic echocardiography

A case of pseudoinfarction electrocardiographic pattern caused by diaphragmatic hernia is presented. The transthoracic echocardiographic examination revealed a large hiatal hernia enhanced by contrast injections below the inferior wall causing paradoxical systolic motion. The location of the hernia simulated a pericardial effusion.

The pivotal role of transesophageal echocardiography in the management of traumatic thoracic aortic rupture with associated intra-abdominal hemorrhage

Rupture of the thoracic aorta after blunt trauma, particularly when associated with multiple injuries, presents a major problem of resuscitation and management. Transesophageal color Doppler echocardiography (TEE) during laparotomy played a major role in confirming the diagnosis of thoracic aortic rupture in a patient.

Impact of the incidental diagnosis of clinically unsuspected central pulmonary artery thromboembolism in treatment of critically ill patients

Mortality is high in unrecognized pulmonary embolism (PE), but the diagnosis is difficult to establish, especially in patients with coexisting cardiopulmonary disorders. We describe a group of 14 patients with pulmonary thromboemboli in whom transesophageal echocardiography (TEE) performed for coexisting cardiopulmonary conditions established the clinical diagnosis of PE not suspected prior to TEE. The patients had initial clinical diagnoses of heart failure (eight patients), cardiogenic shock (two patients), atrial septal defect (two patients), aortic dissection (one patient), and pneumonia (one patient). Thirteen patients had risk factors for PE. Transthoracic echocardiography (TTE) demonstrated right heart strain in eight patients but did not visualize PE in any of the patients. The TEE diagnosis of occult central pulmonary artery thromboembolism changed treatment in all 14 patients. Ten of the 14 patients were successfully discharged from the hospital. We conclude that occult central pulmonary artery thromboemboli are not uncommon in patients presenting with acute cardiopulmonary disorders and the presence of risk factors for PE and right heart strain on TTE should alert the physician to suspect PE. If and when TEE is performed in patients with acute cardiopulmonary disorders with risk factors for PE and right heart strain, the physician should evaluate the main pulmonary artery and its branches for central pulmonary artery thromboemboli.

A polyprotein precursor of two mitochondrial enzymes in Neurospora crassa. Gene structure and precursor processing

N-Acetylglutamate kinase (AGK) and N-acetyl-gamma-glutamyl-phosphate reductase (AGPR) function as two separate mitochondrial enzymes, but are encoded by a single nuclear gene in several fungi. The Neurospora crassa arg-6 gene encoding these enzymes has been cloned and sequenced, and the enzymes responsible for processing the polyprotein precursor have been identified. The 871-amino acid precursor contains a normal N-terminal mitochondrial targeting sequence, an internal connecting region (approximately 200 amino acids) upstream of the distal reductase domain, and coding regions with N-terminal amino acid sequences identical with those of purified N-acetylglutamate kinase and N-acetyl-gamma-glutamyl-phosphate reductase. Sequence comparisons of the coding regions indicate high levels of conservation between prokaryotic and fungal proteins. Regions suggesting ancestral relationships to N-acetylglutamate synthase and aspartate beta-semialdehyde dehydrogenase have been identified. Both the N-terminal targeting sequence and the connecting region contain consensus sites for cleavage by the mitochondrial processing peptidase and processing enhancing protein. In vitro processing assays with intact mitochondria, solubilized mitochondria, and purified enzymes have shown that the mitochondrial processing peptidase and processing enhancing protein cleave not only the N-terminal mitochondrial targeting sequence but also process the polyprotein precursor into the two mature enzymes.

Malignant thymoma. A complicated triad of SVC syndrome, cardiac tamponade, and DIC

A patient presented with multisystem disease due to a very aggressive malignant thymoma. The case was complicated by the triad of cardiac tamponade, superior vena cava (SVC) syndrome, and disseminated intravascular coagulation (DIC). A review of the English literature reveals this to be a unique constellation of clinical symptoms and that DIC was heretofore unreported.

Improvement in circulatory and oxygenation status by perflubron emulsion (Oxygent HT) in a canine model of surgical hemodilution

To examine the effect of a low dose of Oxygent HT on hemodynamics and oxygen transport variables in a canine model of profound surgical hemodilution, two groups of adult anesthetized splenectomized beagles were hemodiluted with Ringer's solution to Hb 7 g/dL. The treated group received 1 mL/kg Oxygent HT (90% w/v perflubron emulsion [perfluorooctyl bromide], Alliance Pharmaceutical Corp.) and both groups (7 controls and 10 treated) were further hemodiluted using 6% hydroxyethyl starch until cardiorespiratory decompensation occurred. Pulmonary artery catheterization data and oxygen transport variables were recorded at Hb decrements of 1 g/dL breathing room air. There was no difference among groups during initial hemodilution. However, in the Oxygent HT group there was a statistically significant improvement in mean arterial pressure, CVP, cardiac output, PvO2, SvO2, DO2, and pulmonary venous admixture shunt during profound hemodilution to Hb levels of 6, 5, and 4 g/dL. A low dose of Oxygent HT offered benefit in improving hemodynamics and oxygen transport parameters even under air breathing conditions in a model of surgical hemodilution. This effect was most apparent at lower levels of Hb.

Arginine transport in mitochondria of Neurospora crassa

Transport of arginine into mitochondria of Neurospora crassa has been studied. Arginine transport was found to be saturable (Km = 6.5 mM) and to have a pH optimum of pH 7.5. Mitochondrial arginine transport appeared to be facilitated transport rather than active transport because: (i) the arginine concentration within the mitochondrial matrix after transport was similar to that of the reaction medium, and (ii) uncouplers and substrates of oxidative phosphorylation did not affect the transport rate. The basic amino acids ornithine, lysine, and D-arginine inhibited arginine transport. The arginine transport system could be irreversibly blocked by treating mitochondria with the reactive arginine derivative, N-nitrobenzyloxycarbonyl-arginyl diazomethane.

Ornithine decarboxylase activity in tumor and normal tissue of head and neck cancer patients

Tumorigenesis requires increased biosynthesis of polyamines and elevated levels of ornithine decarboxylase, which is the rate-limiting enzyme in the polyamine synthesis pathway. Previous animal studies have noted a marked increase in ornithine decarboxylase after exposure to tumorigenic stimuli and that pretreatment with vitamins A and E provides protection against the carcinogenic action. However, studies of ornithine decarboxylase activity in human oral cavity carcinoma have not been as specific. The goal of this study was to determine whether a specific difference in ornithine decarboxylase activity occurs in tumor versus adjacent normal tissue in head and neck squamous cell carcinoma patients. Ornithine decarboxylase activity was measured in 30 consecutive head and neck cancer patients undergoing surgical therapy. Ornithine decarboxylase levels were found to be significantly elevated in tumor tissue samples when compared to adjacent normal mucosa samples (P less than .004). This finding confirms the previous findings noted in animal models and implies that the protective effects of vitamins A and E will extend to human head and neck cancers.

A clinical laboratory management elective for pathology residents

Many practicing pathologists, particularly those in private settings, function as managers. Their responsibilities may not only involve directing the successful activities of laboratory personnel, but often require a level of accountability to hospital administrators or business managers. Traditional training programs focus on technical competency and devote little time, if any, to preparing their graduates for the management aspects of their careers. In response to this need, a 1-month elective was designed for senior pathology residents at the University of Utah, Salt Lake City. The cumulative experiences of a large academic pathology department and its successful commercial laboratory venture provided a real-world supplement to a curriculum founded in basic business management principles.

Multichamber gunshot wounds of the heart. The utility of transesophageal echocardiography

A patient had a gunshot wound to the heart involving three cardiac chambers. Conventional echocardiography failed to identify the intracardiac injuries. The utility of transesophageal echocardiography in a patient with cardiac trauma is described.