KL2 scholars' perceptions of factors contributing to sustained translational science career success

Introduction

Identifying the most effective ways to support career development of early stage investigators in clinical and translational science should yield benefits for the biomedical research community. Institutions with Clinical and Translational Science Awards (CTSA) offer KL2 programs to facilitate career development; however, the sustained impact has not been widely assessed.

Methods

A survey comprised of quantitative and qualitative questions was sent to 2144 individuals that had previously received support through CTSA KL2 mechanisms. The 547 responses were analyzed with identifying information redacted.

Results

Respondents held MD (47%), PhD (36%), and MD/PhD (13%) degrees. After KL2 support was completed, physicians' time was divided 50% to research and 30% to patient care, whereas PhD respondents devoted 70% time to research. Funded research effort averaged 60% for the cohort. Respondents were satisfied with their career progression. More than 95% thought their current job was meaningful. Two-thirds felt confident or very confident in their ability to sustain a career in clinical and translational research. Factors cited as contributing to career success included protected time, mentoring, and collaborations.

Conclusion

This first large systematic survey of KL2 alumni provides valuable insight into the group's perceptions of the program and outcome information. Former scholars are largely satisfied with their career choice and direction, national recognition of their expertise, and impact of their work. Importantly, they identified training activities that contributed to success. Our results and future analysis of the survey data should inform the framework for developing platforms to launch sustaining careers of translational scientists.

Structure activity relationships of human galactokinase inhibitors

Classic Galactosemia is a rare inborn error of metabolism that is caused by deficiency of galactose-1-phosphate uridyltransferase (GALT), an enzyme within the Leloir pathway that is responsible for the conversion of galactose-1-phosphate (gal-1-p) and UDP-glucose to glucose-1-phosphate and UDP-galactose. This deficiency results in elevated intracellular concentrations of its substrate, gal-1-p, and this increased concentration is believed to be the major pathogenic mechanism in Classic Galactosemia. Galactokinase (GALK) is an upstream enzyme of GALT in the Leloir pathway and is responsible for conversion of galactose and ATP to gal-1-p and ADP. Therefore, it was hypothesized that the identification of a small-molecule inhibitor of human GALK would act to prevent the accumulation of gal-1-p and offer a novel entry therapy for this disorder. Herein we describe a quantitative high-throughput screening campaign that identified a single chemotype that was optimized and validated as a GALK inhibitor.

4-(3-Chloro-5-(trifluoromethyl)pyridin-2-yl)-N-(4-methoxypyridin-2-yl)piperazine-1-carbothioamide (ML267), a potent inhibitor of bacterial phosphopantetheinyl transferase that attenuates secondary metabolism and thwarts bacterial growth

4′-Phosphopantetheinyl transferases (PPTases) catalyze a post-translational modification essential to bacterial cell viability and virulence. We present the discovery and medicinal chemistry optimization of 2-pyridinyl-N-(4-aryl)piperazine-1-carbothioamides, which exhibit submicromolar inhibition of bacterial Sfp-PPTase with no activity toward the human orthologue. Moreover, compounds within this class possess antibacterial activity in the absence of a rapid cytotoxic response in human cells. An advanced analogue of this series, ML267 (55), was found to attenuate production of an Sfp-PPTase-dependent metabolite when applied to Bacillus subtilis at sublethal doses. Additional testing revealed antibacterial activity against methicillin-resistant Staphylococcus aureus, and chemical genetic studies implicated efflux as a mechanism for resistance in Escherichia coli. Additionally, we highlight the in vitro absorption, distribution, metabolism, and excretion and in vivo pharmacokinetic profiles of compound 55 to further demonstrate the potential utility of this small-molecule inhibitor.

A comparison of the ability of rilpivirine (TMC278) and selected analogues to inhibit clinically relevant HIV-1 reverse transcriptase mutants

Background

The recently approved anti-AIDS drug rilpivirine (TMC278, Edurant) is a nonnucleoside inhibitor (NNRTI) that binds to reverse transcriptase (RT) and allosterically blocks the chemical step of DNA synthesis. In contrast to earlier NNRTIs, rilpivirine retains potency against well-characterized, clinically relevant RT mutants. Many structural analogues of rilpivirine are described in the patent literature, but detailed analyses of their antiviral activities have not been published. This work addresses the ability of several of these analogues to inhibit the replication of wild-type (WT) and drug-resistant HIV-1.

Results

We used a combination of structure activity relationships and X-ray crystallography to examine NNRTIs that are structurally related to rilpivirine to determine their ability to inhibit WT RT and several clinically relevant RT mutants. Several analogues showed broad activity with only modest losses of potency when challenged with drug-resistant viruses. Structural analyses (crystallography or modeling) of several analogues whose potencies were reduced by RT mutations provide insight into why these compounds were less effective.

Conclusions

Subtle variations between compounds can lead to profound differences in their activities and resistance profiles. Compounds with larger substitutions replacing the pyrimidine and benzonitrile groups of rilpivirine, which reorient pocket residues, tend to lose more activity against the mutants we tested. These results provide a deeper understanding of how rilpivirine and related compounds interact with the NNRTI binding pocket and should facilitate development of novel inhibitors.

Mirabamides E-H, HIV-inhibitory depsipeptides from the sponge Stelletta clavosa

Four new depsipeptides, mirabamides E-H (1-4), and the known depsipeptide mirabamide C (5) have been isolated from the sponge Stelletta clavosa, collected from the Torres Strait. The planar structures were determined on the basis of extensive 1D and 2D NMR and HRESIMS. The absolute configurations were established by the advanced Marfey's method, NMR, and GC-MS. The four new compounds all showed strong inhibition of HIV-1 in a neutralization assay with IC(50) values of 121, 62, 68, and 41 nM, respectively.

The karyopherin Kap95 and the C-termini of Rfa1, Rfa2, and Rfa3 are necessary for efficient nuclear import of functional RPA complex proteins in Saccharomyces cerevisiae

Nuclear protein import in eukaryotic cells is mediated by karyopherin proteins, which bind to specific nuclear localization signals on substrate proteins and transport them across the nuclear envelope and into the nucleus. Replication protein A (RPA) is a nuclear protein comprised of three subunits (termed Rfa1, Rfa2, and Rfa3 in Saccharomyces cerevisiae) that binds single-stranded DNA and is essential for DNA replication, recombination, and repair. RPA associates with two different karyopherins in yeast, Kap95, and Msn5/Kap142. However, it is unclear which of these karyopherins is responsible for RPA nuclear import. We have generated GFP fusion proteins with each of the RPA subunits and demonstrate that these Rfa-GFP chimeras are functional in yeast cells. The intracellular localization of the RPA proteins in live cells is similar in wild-type and msn5Δ deletion strains but becomes primarily cytoplasmic in cells lacking functional Kap95. Truncating the C-terminus of any of the RPA subunits results in mislocalization of the proteins to the cytoplasm and a loss of protein-protein interactions between the subunits. Our data indicate that Kap95 is likely the primary karyopherin responsible for RPA nuclear import in yeast and that the C-terminal regions of Rfa1, Rfa2, and Rfa3 are essential for efficient nucleocytoplasmic transport of each RPA subunit.

Celebesides A-C and theopapuamides B-D, depsipeptides from an Indonesian sponge that inhibit HIV-1 entry

Six new depsipeptides belonging to two different structural classes, termed celebesides A-C and theopapuamides B-D, have been isolated from the marine sponge Siliquariaspongia mirabilis. Their structures were determined using extensive 2D NMR and ESI-MS/MS techniques. Celebesides are unusual cyclic depsipeptides that comprise a polyketide moiety and five amino acid residues, including an uncommon 3-carbamoyl threonine, and a phosphoserine residue in celebesides A and B. Theopapuamides B-D are undecapeptides with an N-terminal fatty acid moiety containing two previously unreported amino acids, 3-acetamido-2-aminopropanoic acid and 4-amino-2,3-dihydroxy-5-methylhexanoic acid. The relative configuration of the polyketide moiety in celebesides was resolved by J-based analysis and quantum mechanical calculations, the results of which were self-consistent. Celebeside A neutralized HIV-1 in a single-round infectivity assay with an IC(50) value of 1.9 +/- 0.4 microg/mL while the nonphosphorylated analog celebeside C was inactive at concentrations as high as 50 microg/mL. Theopapuamides A-C showed cytotoxicity against human colon carcinoma (HCT-116) cells with IC(50) values between 2.1 and 4.0 microg/mL and exhibited strong antifungal activity against wildtype and amphotericin B-resistant strains of Candida albicans at loads of 1-5 microg/disk.

Mirabalin, [corrected] an antitumor macrolide lactam from the marine sponge Siliquariaspongia mirabilis

A new highly unsaturated macrolide lactam, termed mirabilin ( 1), was isolated from the aqueous extract of the marine sponge Siliquariaspongia mirabilis. Mirabilin is characterized by the presence of a 35-membered macrolide lactam ring bearing a pentadiene conjugated system and a tetrasubstituted tetrahydropyran ring. A linear polyketide moiety is attached to the macrocyclic ring through an amide linkage. The structure of mirabilin was determined using extensive 2D NMR and ESIMS and tandem MS techniques. Mirabilin inhibits the growth of the tumor cell line HCT-116 with an IC 50 value of 0.27 +/- 0.09 microM and is noncytotoxic to several other cell lines.

Mirabamides A-D, depsipeptides from the sponge Siliquariaspongia mirabilis that inhibit HIV-1 fusion

Four new cyclic depsipeptides termed mirabamides A-D (1-4) have been isolated from the marine sponge Siliquariaspongia mirabilis and shown to potently inhibit HIV-1 fusion. Their structures were elucidated by NMR and ESIMS, and absolute stereochemistry of the amino acids was determined using advanced Marfey's methods and NMR. Mirabamides contain two new entities, including 4-chlorohomoproline in 1-3 and an unusual glycosylated amino acid, beta-methoxytyrosine 4'-O-alpha-L-rhamnopyranoside (in 1, 2, and 4), along with a rare N-terminal aliphatic hydroxy acid. These elements proved to be useful for anti-HIV structure-activity relationship studies. Mirabamide A inhibited HIV-1 in neutralization and fusion assays with IC50 values between 40 and 140 nM, as did mirabamides C and D (IC50 values between 140 nM and 1.3 microM for 3 and 190 nM and 3.9 microM for 4), indicating that these peptides can act at the early stages of HIV-1 entry. The potent activity of depsipeptides containing the glycosylated beta-OMe Tyr unit demonstrates that beta-OMe Tyr itself is not critical for activity. Mirabamides A-C inhibited the growth of B. subtilis and C. albicans at 1-5 microg/disk in disk diffusion assays.

Slow changes in cytosolic free Ca2+ in Escherichia coli highlight two putative influx mechanisms in response to changes in extracellular calcium

Free intracellular Ca2+ ([Ca2+]i) in Escherichia coli was measured using the bioluminescent protein aequorin. Overall, the bacteria maintained a tight control on their free [Ca2+]i. The results indicated a slow Ca2+ influx, the magnitude of the initial rise in free [Ca2+]i being dependent upon the concentrations of external Ca2+. This was followed by the slow removal of free Ca2+ until normal levels were restored. Specifically, addition of external Ca2+ (0.25-10 mM) resulted in a gradual rise in intracellular free Ca2+ from a basal level of approximately 272 nM, maximally reaching a peak of 0.85-5.4 microM within 30-40 min. This was followed by a slow fall over the next 30 min, culminating in an oscillatory pattern of free [Ca2+]i (range 0.3-0.7 microM for 0.25 mM external Ca2+). In the presence of EGTA, free [Ca2+]i was dramatically reduced. Neither the influx of Ca2+ nor restoration of intracellular free Ca2+ required protein synthesis. Moreover, preincubation with Ca2+ increased the rising phase of intracellular Ca2+ in response to further exposure to external Ca2+. This was further evidence against a specific adaptation process such as the synthesis of calcium exporters. A putative Ca2+ influx channel was demonstrated in stationary phase cells in particular, which could be blocked by La3+. This channel was consistent with the voltage-activated poly-3-hydroxybutyrate/polyphosphate Ca2+ channels previously detailed by Reusch et al. [23] Even in the presence of La3+, however, the free [Ca2+]i of log phase and stationary phase bacteria still increased two-fold over resting values in response to external Ca2+. This suggested the presence of at least two Ca2+ influx processes, one inhibited by La3+ and the other not.

Intermittent pneumatic compression effect on eccentric exercise-induced swelling, stiffness, and strength loss

OBJECTIVE

The purpose was to determine if intermittent pneumatic compression (IPC) affects muscle swelling, stiffness, and strength loss resulting from eccentric exercise-induced injury of the elbow flexors. We hypothesized that the compression would decrease swelling and stiffness.

DESIGN

Repeated measures design with a before-after trial comparison within each day.

SETTING

Conducted at a university Somatic Dysfunction Laboratory.

SUBJECTS

Twenty-two college women students were studied. They had not been lifting weights or otherwise participating in regular arm exercise for the 6 months before the study. They had no history of upper extremity injury or cardiovascular disease.

INTERVENTIONS

Subjects performed one bout of eccentric exercise at a high load to induce elbow flexor muscle injury. Uniform IPC was applied on the day of exercise and daily for 5 days at 60mmHg, 40 seconds inflation, 20 deflation for 20 minutes.

MAIN OUTCOME MEASURES

Measurements of arm circumference, stiffness, and isometric strength were recorded before exercise, then before and after IPC for 5 days after exercise. Passive muscle stiffness was measured on a device that extends the elbow stepwise and records the torque required to hold the forearm at each elbow angle.

RESULTS

Circumference and stiffness increased and strength decreased during the 5 days post-exercise (p < .05). IPC significantly decreased circumference and stiffness most notably on days 2 and 3 after exercise (p < .05). The strength loss was not affected by IPC.

CONCLUSION

IPC is effective in temporarily decreasing the swelling and stiffness after exercise-induced muscle injury.

The many faces of atypical sinusitis

The physician must be alert to the possibility of unsuspected sinusitis when evaluating a patient with chronic cough, sore throat, fever of unknown origin, supraglottitis, pneumonia, or headache. This article presents four cases in which atypical or asymptomatic sinusitis was discovered that could have caused significant or potentially life-threatening complications. In each case, the sinusitis was initially unsuspected. A complete nasal evaluation is warranted following decongestion of the nasal cavity when conditions are present. A screening sinus computed tomography scan may be indicated when sinusitis is strongly suspected even in the absence of typical clinical symptoms. Exact identification of the organism causing the infection may require sinus aspirate or tissue culture.

Laser excision of hypopharyngeal lesions using a transoral approach

A transoral technique for the excision of primary hypopharyngeal, posterior pharyngeal, and lateral pharyngeal wall tumors using the CO(2) or KTP laser and an operating microscope is presented.

Predictors of intracranial carotid artery atherosclerosis. Duration of cigarette smoking and hypertension are more powerful than serum lipid levels

The effect of cigarette smoking on intracranial internal carotid artery atherosclerosis (ICAS) was studied by obtaining cigarette smoking histories and data on other potential predictors, including serum lipid estimations, for consecutive patients undergoing carotid arteriography. The duration of cigarette smoking was the most significant independent predictor of the presence of ICAS. Other independently significant predictors of ICAS were hypertension, diabetes mellitus, and current systolic blood pressure. The interaction of diabetes and duration of smoking was a significant negative predictor. In patients for whom serum lipid values were available, lower levels of apolipoprotein A-I were associated with a higher risk of having ICAS. However, the effect of apolipoprotein A-I as a predictor of the presence of ICAS was far outweighted by the effects of duration of smoking and hypertension.

Serum lipids and lipoproteins are less powerful predictors of extracranial carotid artery atherosclerosis than are cigarette smoking and hypertension

The effect of serum lipids and lipoproteins on extracranial carotid artery atherosclerosis (CAS) was studied in patients who underwent carotid arteriography. Serum lipid and lipoprotein values along with data on other potential predictors of extracranial CAS were determined in 240 patients who had at least one extracranial carotid artery visualized. In a multiple logistic regression analysis, the independently significant predictors of the presence of extracranial CAS were, in decreasing order of significance, duration of smoking of cigarettes, hypertension, age, and low-density lipoprotein cholesterol. Serum cholesterol, triglycerides, high-density lipoprotein cholesterol, and apolipoprotein A-I did not show an independent effect. Although low-density lipoprotein cholesterol was an independent predictor of the presence of extracranial CAS, its effect as a predictor was far outweighed by the effects of the duration of smoking of cigarettes and a history of hypertension.

Duration of cigarette smoking is the strongest predictor of severe extracranial carotid artery atherosclerosis

The effect of cigarette smoking on extracranial carotid atherosclerosis was studies by obtaining cigarette smoking histories and information on other potential risk factors from consecutive patients undergoing carotid arteriography. At least on extracranial carotid artery was visualized in 752 patients in whom the extent of carotid atherosclerosis was assessed. The total years of cigarette smoking was the most significant independent predictor of the presence of severe carotid atherosclerosis. Other independent predictors, in order of significance, were age, hypertension, diabetes mellitus, male sex, and current systolic blood pressure. By age 60 years, the risk of having severe carotid atherosclerosis for a person who had smoked for 40 years was approximately 3.5 times that for a never smoker. The major benefit of smoking cessation is in limiting the accumulation of smoking years.

Spinal cord sarcoidosis: a new finding at MR imaging with Gd-DTPA enhancement

Three patients with histologically confirmed sarcoidosis with spinal cord involvement were examined with high-field-strength magnetic resonance imaging (1.5 T) before and after the administration of gadolinium diethylenetriaminepentaacetic acid. In addition to intramedullary expansion, areas of patchy, multifocal, parenchymal enhancement and areas of linear peripheral enhancement were seen in all three patients; these findings have not been previously reported and are unusual for other more common spinal cord lesions. This observation led to a correct diagnosis and a limitation of the extent of biopsy in two of the cases. Unfortunately, this enhancement pattern is not specific for sarcoidosis, as the authors have observed similar findings in two cases of biopsy-proved myelitis and multiple sclerosis. The peripheral enhancement is thought to be located in the leptomeninges due to leptomeningeal involvement, which was proved histologically in one case. This pattern of involvement, while not specific, is certainly consistent with and, in the appropriate clinical setting, highly suggestive of sarcoidosis.

Anatomical and profile analysis of the female black American nose

An anatomical and anthropometric study was conducted that compared nasal pyramid measurements of Negroid with Caucasian skulls and surface measurements of black with Caucasian controls. Eight external surface measurements were used to develop a classification system to show the range of the female black American nose. This classification will be described along with the range of measurements on which it is based. This classification may provide a better understanding of the anatomic characteristics of the normal variation of Negroid noses, and thus improve the surgeon's ability to evaluate black patients for rhinoplasty.

Predictive value of carotid bruit for carotid atherosclerosis

To assess the predictive value of carotid bruit for moderate-to-severe carotid atherosclerosis, the results of carotid arteriograms performed on 1004 subjects were correlated with the findings of auscultation of the carotid arteries. Predictive values of carotid bruit for ipsilateral extracranial carotid atherosclerosis were 77% for localized bruits and 74% for diffuse bruits. The predictive values of extracranial carotid bruit for ipsilateral intracranial carotid atherosclerosis were 16% for localized bruits and 18% for diffuse bruits. Assessing both carotid arteries together, the predictive value of carotid bruit for moderate-to-severe atherosclerosis at any extracranial carotid site was 85%, there being no difference whether the bruits were diffuse, localized, bilateral, or unilateral. Diffuse or localized bruits, whether unilateral or bilateral, are equally predictive of moderate-to-severe atherosclerosis in the extracranial carotid artery, but both are poor predictors of intracranial carotid artery disease.

Central pontine myelinolysis and its imitators: MR findings

The clinical, radiologic, and neuropathologic findings in 13 patients with central pontine myelinolysis were reviewed. Antemortem computed tomography (CT) had been performed in nine, and ante- or postmortem magnetic resonance (MR) imaging in 11. Chronic alcoholism or rapid correction of hyponatremia was present in over 75% of cases. One CT scan was positive, but only on retrospective review. In all but one patient, MR imaging eventually revealed an abnormality within the pons; in two patients the initial study was normal. The lesions varied in shape, with peripheral involvement in two patients and extrapontine involvement in four. The abnormality was smaller at 6-month follow-up in one patient and unchanged at 1 year in another. One patient never had a demonstrable pontine lesion but did have symmetric basal ganglia abnormalities, which were consistent with extrapontine myelinolysis. MR imaging disclosed similar central pontine alterations resulting from infarct, metastasis, glioma, multiple sclerosis, encephalitis, and radiation or chemotherapy; thus, such changes are not unique.

MR findings in normal-pressure hydrocephalus: significance and comparison with other forms of dementia

This study was undertaken to identify findings on magnetic resonance (MR) imaging that might possibly differentiate among several dementia states in the elderly or predict response to shunt therapy in patients with normal-pressure hydrocephalus (NPH). The MR findings were retrospectively reviewed in 54 patients who were divided into four clinical categories: NPH (17 patients), obstructive hydrocephalus (eight patients), Alzheimer disease (eight patients), and non-Alzheimer dementia (21 patients). Three MR findings were evaluated in each case: increased periventricular (PVS) and white matter (WMS) signal on T2-weighted images, CSF flow void sign (CFVS) in the aqueduct, and corpus callosum thinning. Neither the PVS/WMS nor corpus callosum thinning patterns were useful for distinguishing among the four clinical groups. At low field strength, the absence of a marked or moderate CFVS, however, may militate against a diagnosis of NPH. All 17 patients with NPH underwent a shunt procedure after the MR study. A better response to shunt therapy occurred in patients without WMS and with more severe PVS.

Glomus tympanicum chemodectomas: radiographic and clinical characteristics

Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.

Elevation of serum creatine kinase B-subunit levels by radiographic contrast agents in patients with neurologic disorders

The effect of radiographic contrast agents on the central nervous system was evaluated by measurement of serum creatine kinase B-subunit (CKB) levels with use of radioimmunoassay in 58 patients who underwent computed tomographic (CT) scanning and 46 patients who underwent cerebral angiography for evaluation of cerebrovascular diseases, brain tumors, and other neurologic disorders. In 11 patients (10.6%), the CKB increased to abnormally high levels within 4 hours after the radiographic procedures, and the median value after 30 minutes was significantly higher than the corresponding precontrast value (P less than 0.01). Eight of the 11 patients had recent ischemic cerebrovascular diseases, and 7 of the 11 had undergone CT scanning. On the basis of the information available in the literature, elevation of the serum CKB levels may be interpreted as reflecting breakdown of the blood-brain barrier and neural damage. Intravascularly administered radiographic media are generally safe, but the results of the current investigation suggested the potential for detrimental effects, particularly in patients with recent cerebrovascular diseases.

Magnetic resonance imaging and clinical relationships in multiple sclerosis

Magnetic resonance imaging (MRI) was done in 109 patients with suspected demyelinating disease (56 with clinical multiple sclerosis [MS] and 53 without). Of those with clinical MS, 43 (77%) had multifocal lesions of the white matter detected on MRI; 12 of the 43 also had confluent periventricular signaling. Nine patients (17%) without clinical MS had similar findings. Of the 56 patients with MS, 35 underwent both computed tomography (CT) and MRI. In this group, 80% of MRI scans showed multiple demyelinating lesions compatible with MS, as compared with 29% of the CT scans. A CT scan was "positive" more often if obtained within 1 month after an attack of MS than later. In contrast, the sensitivity of MRI or the number of lesions detected by MRI did not increase in patients with recent exacerbations. MRI was "positive" in patients with clinical MS more often than was any single evoked response study. In statistical analyses, both the sensitivity of MRI and the number of lesions were associated with the duration of MS. A pattern of confluent periventricular signaling around the lateral ventricle was associated with greater duration of MS and patient disability.

Correlation of radiological features to failure of lumbar intervertebral disc chemonucleolysis

Chemonucleolysis was performed in 103 patients for lumbar disc prolapse. Multiple (two) interspaces were injected in only seven patients. Radiographically, all patients had myelographic or computerized tomography evidence of disc prolapse. Eighty-seven of 100 patients who were available for follow-up review had improved. Ten of 13 patients with persistent symptoms required a laminectomy. Altered spinal alignment was evident in five of the 13 patients with persistent symptoms: retrolisthesis in three and myelographic disc defect on the convex aspect of the scoliosis in two. Review of radiographic studies was carried out in an attempt to establish guidelines for patient selection so as to decrease the rate of failure in chymopapain treatment.

The application of magnetic resonance imaging in otolaryngology

Magnetic resonance imaging is a new diagnostic technique that is being applied to study disease processes that involve the upper aerodigestive tract and cranial nerves of interest to otolaryngologists. As with all imaging techniques, an in-depth knowledge of the normal anatomy of a region is a prerequisite for the appreciation of disease states. In addition, magnetic resonance imaging requires a familiarity with the signal intensity produced by the different structures and the relationship of that signal to various radiofrequency pulse sequences that may be used. This report briefly reviews the techniques of magnetic resonance imaging and the normal anatomy of the cervical region and presents examples of pathologic processes that have been studied with this powerful diagnostic technique.

CT of the sella turcica after transsphenoidal resection of pituitary adenomas

A retrospective review of 120 patients undergoing transsphenoidal surgery for pituitary adenomas revealed that computed tomography (CT) was less sensitive and less specific than hormonal methods in identifying residual functioning adenomas. However, CT was the only useful method of evaluating nonfunctioning tumors, including pseudo-prolactinomas. Enlargement of the pituitary stalk, when seen on preoperative CT, was 100% predictive of "cure" if the enlargement returned to normal size on a remote follow-up scan (n = 8) and was 100% predictive of residual tumor if the enlargement persisted or evolved (n = 8). Resolution of stalk displacement was the next most reliable predictor of cure (91%, n = 11), but persistent displacement was less reliable than abnormal intrasellar enhancement in predicting the presence of residual tumor (71%, n = 28, vs. 81%, n = 26). Enhancement in the postoperative sella by other than normal pituitary gland was presumed to be due to inflammation in 19% of patients. Inflammatory enhancement was observed in the presence of autograft and homograft muscle plugs and, unlike enhancement due to untreated tumors, was observed to decrease in size and intensity with time. Intrasellar enhancement was an unreliable criterion of success or failure in cases of microadenoma. All 14 patients with functioning adenomas and preoperative parasellar tumor extension had persistent tumor at postoperative evaluation. Of the 47 patients with resected functioning adenomas who had CT scans showing empty or partly empty sellas after operation, 22 (47%) had hormonally detectable residual tumor.

Magnetic resonance imaging in syringomyelia

Myelography and myelography assisted with computed tomography have been the most commonly used radiographic methods in the study of syringomyelia. These studies have never been entirely reliable in demonstrating the syrinx cavity and its relationship to other intracranial structures. During the 1st year of operation of the magnetic resonance imaging facility, the syringomyelic cavity was demonstrated in 15 patients who all had typical clinical signs and symptoms associated with syringomyelia. Nine cases were syringomyelia with Chiari malformation. One case showed additional hydrocephalus. Four cases were idiopathic, and 1 case was remotely posttraumatic. Magnetic resonance imaging, although it is in its infancy, already promises to be the most important radiographic technique for syringomyelia because it provides an anatomically truthful visualization of the sagittal plane of the cervical cord and can demonstrate the syrinx cavity and its relationship with the cerebellar tonsils, the 4th ventricle, and other related structures.

Lumbar spinal stenosis. Clinical features, diagnostic procedures, and results of surgical treatment in 68 patients

Our experience with 68 patients with strictly defined, myelographically proven, surgically confirmed lumbar spinal stenosis seen over a 30-month period was reviewed. Pseudoclaudication was the commonest symptom (94%) and was described by patients as pain (93%), numbness (63%), or weakness (43%). Symptoms were frequently bilateral (68%) and generally relieved by flexing the lumbosacral spine. Neurologic abnormalities were found in a minority of patients and were usually mild. Electromyography showed one or more lumbosacral radiculopathies in 34 of 37 patients examined. Radiographic evidence of degenerative disk or joint disease was found in 63 patients. All patients had stenosis on myelography, with narrowing at L2, L3, and L4 being the commonest; 30% had multi-level stenosis. Two of ten computed tomograms were normal. Surgery was extensive; 72% of patients had three or more laminae removed. At a mean of 4 years after surgery, 84% of patients reported that surgery had yielded good to excellent results.

Magnetic resonance imaging in a routine clinical setting

The results of magnetic resonance imaging (MRI) examinations in the first 1,000 consecutive patients who were studied by this technique at our institution were reviewed to determine the disease states encountered, the sensitivity and accuracy of results, and the value of the examination as compared with computed tomography and other imaging procedures. The MRI device was a 0.15-tesla resistive magnet that used a variety of saturation recovery, spin echo, and inversion recovery pulse sequences to produce images. MRI was found equal to or superior to other imaging techniques in most cases. Exceptions included organs or body regions that are prone to excessive respiratory or vascular motion, lesions that necessitate exquisite spatial resolution for diagnosis, and lesions in which angulation of the viewing plane is necessary for optimal depiction. Fresh blood and calcification within a lesion were also difficult to detect with use of MRI.

Spontaneous cervical cephalic arterial dissection and its residuum: angiographic spectrum

Cervical cephalic dissections are uncommon acute disruptions of the arterial wall occurring predominantly in middle-aged women. Clinically, most patients present with unilateral headache, oculosympathetic palsy, or ischemic neurologic symptoms. Usually, a single internal carotid artery, predominantly the right, is affected, but simultaneous multivessel dissections are evident in about one-third of patients. Angiographically, the appearance of the dissection varies, depending on its severity, extent, and the interval between onset and angiography. In the patients reported, the disruption was manifested initially by eccentric tapered stenosis in 47%, tapered stenosis and a dissecting aneurysm in 28%, occlusion in 18%, or a dissecting aneurysm alone in 7%. Subsequently, stenotic dissections resolved in 60%, improved in 20%, and progressed in 15%, while dissecting aneurysms diminished in half and resolved in one-fourth of patients. An angiographic residuum, temporally remote to its onset, was evident in 25% of dissections. Hence, carotid arterial dissections tend to resolve, sometimes progress, but seldom recur.

Computer analysis of orbital fat and muscle volumes in Graves ophthalmopathy

A technique using special computer programs and data from high-resolution computed tomographic scans has been developed that provides accurate and reproducible volume measurements for muscle and fat in the orbit. Normal values for retrobulbar fat and muscle were established in 19 adults. Nineteen patients with Graves exophthalmopathy were then studied, and a spectrum of change was found that included varying degrees of increased muscle volume or increased volume of both muscle and fat. Further categorization of these changes related to clinical characteristics should lead to a better understanding of the mechanism for ophthalmopathy in Graves disease.

Aneurysmal bone cyst of the ethmoid

Although nearly 500 cases of aneurysmal bone cyst have been recorded in the English literature, involvement of the facial bone is uncommon. To our knowledge, this is the first case of extragnathic, facial aneurysmal bone cyst to be reported in the English literature. A left ethmoid aneurysmal bone cyst was found in a 20-year-old pregnant woman who had a 5-month history of progressive left periorbital swelling, left cystic nasal mass, progressive nasal obstruction, blurred vision, and occasional diplopia. The diagnostic evaluation included a sinus series, facial lamiograms, and an EMI scan. Needle aspirates taken frequently from the intranasal cyst consisted of a dark bloody fluid. The surgical procedure, using external rhinotomy approaches, pathologic findings, and a literature review are presented.

Manifestations and management of laryngoceles

Six cases of laryngocele are reported including 2 bilateral, external laryngoceles, 1 internal laryngocele associated with amyloidosis, and 3 combined laryngoceles. Laryngoceles occur predominantly in males. Cervical mass and hoarseness were the most common signs and symptoms. Bilateral, external laryngoceles that decompress spontaneously when intralaryngeal air pressure returns to normal were managed conservatively. Combined and internal laryngoceles should be removed surgically through an external, lateral neck approach. This approach is preferable to anterior laryngofissure because it avoids trauma to the anterior commissure and the true vocal cords. In addition, blunting of the anterior commissure and the risk of subglottic stenosis are avoided.

Evaluation of bone scan by scintigraphy to detect subclinical invasion of the mandible by squamous cell carcinoma of the oral cavity

A prospective study using scintigraphy was performed to compare the sensitivity of the Panorex roentgenogram and the bone scan in detecting subclinical invasion of the mandible by squamous cell carcinoma of the oral cavity and floor of the mouth. Twenty-five patients with squamous cell carcinoma of the floor of the mouth were evaluated preoperatively by both the Panorex and scintigraphic techniques and the results compared with postoperative pathologic findings. In 13 (52%) of the cases, Panorex and scintigraphic techniques were comparable in detecting tumor involvement in bone. In eight cases (32%) all three modalities had normal pathologic indications of the mandible. However, in four cases (16%) results of the scintigraphic techniques were abnormal and the Panorex, normal. In four separate cases, the extent of lesion demonstrable by scintiscanning was greater than delineated by Panorex; surgical specimen confirmed this finding. Pathologic examination of operative specimens confirmed tumor involvement. These data lead us to believe that the scintigraphic techniques may be more sensitive in detecting early mandibular involvement with squamous cell carcinoma than the Panorex technique and may help alter the therapeutic approach.

Nuclear magnetic resonance imaging

Nuclear magnetic resonance scanning provides the potential for measurement of new properties of tissue which may permit better pathologic differentiation. NMR will be less affected by bone, and so neurologic studies in which bone artifacts are a problem in CT may be facilitated. Direct sagittal and coronal imaging are possible. As far as we know, the biologic hazards are expected to be minimal but cannot be definitely ruled out at this time. At present, the relaxation times that are most frequently measured are such that clinically acceptable spatial resolution (2 to 3mm) requires scan times on the order of two minutes or more. Whether chemical cross-sections that are acceptable to clinical demands can be obtained remains to be demonstrated.

Radiologic evaluation of ischemic cerebrovascular syndromes with emphasis on computed tomography

In patients with stroke syndromes, the extent and sequence of investigations are based upon clinical probabilities and take into account the age, general condition, and wishes of the patient. There is no doubt that the evaluation of such patients has been changed and improved by CT. The incidence of intraparenchymal bleeding is higher, but its mortality is lower than previously believed. The incidence of hemorrhagic infarction is probably not as great as previously suspected, but the hazards of anticoagulant therapy in a patient with a hemorrhagic infarct are easily obviated if a CT scan is obtained before anticoagulant therapy is started. The initial evaluation of the patient has been improved by CT, but in addition, following the course of the patient is easier by obtaining serial scans when satisfactory recovery does not take place or continue at the expected rate. Parenchymal changes such as hemorrhagic change, mass effect, or obstruction of the ventricular system can be detected early, and approached rationally.

Dynamic sequential scanning with table incrementation

Dynamic sequential scanning with table incrementation is a method of rapid computed tomographic head scanning in which a complete 10-section scan can be made in 2 minutes 40 seconds or less. Although some measurable and visible loss of low-contrast resolution occurs, there is no loss of high-contrast resolution. Monthly throughput of patients has been increased by about 30% since this technique was instituted.

The clinical usefulness of routine coronal and sagittal reconstructions in cranial computed tomography

In order to test a hypothesis that the routine use of one midsagittal and four preselected coronal reconstruction images would disclose lesions unsuspected on standard cranial computed tomography (CT) scans, 204 patient examinations were subjected to such multiplanar reconstruction manipulation; the original CT diagnoses, reconstruction diagnoses, and final clinical diagnoses were compared. The two CT diagnoses agreed in 144 cases. Lesions well shown on the standard CT examination were not seen on the reconstruction images in 23 cases (11% of the total), and reconstruction revealed brainstem or cerebellar atrophy not detected on standard CT in 37 cases (18% of the total). Applications of these findings to daily neuroradiologic practice are suggested.

Screening for brain lesions with digital radiography of the head using a CT scanner

Digital radiography was tested in a clinical setting as a screening device for detecting brain lesions and for following the response of known enhancing cranial masses to therapy. A concurrent phantom study was conducted to determine the low contrast sensitivity of the system. Contrast resolution was superior to that of film -- screen systems but suffered at a density level of 2 to 4% because of system noise. This noise appeared to be nonquantum in nature, related to electronic and mechanical inconsistencies of the computed tomographic instrument. System noise and patient motion combined to nullify the advantages of digital radiography for screening and monitoring intracranial masses.

Pituitary and parapituitary tumours on computed tomography. A review article based on 230 cases

This paper is based on a retrospective study of 230 tumours in the sellar area. All, except a few, were examined with the EMI 160 x 160 matrix and verified histologically. The main features of each pathological entity are described and most of the previous literature is reviewed. The degree of resolution of the scanner used precludes its reliability for detecting tumours less than one centimetre in diameter. Out of 30 microadenomas, only two were detectable on CT. This reflects an incidence of false negative results in 93% of microadenomas or 22% of all adenomas in the series. CT was also negative in 6% of craniopharyngiomas and 30% of chordomas. These findings emphasize the need for further neuroradiological tests in patients with clinically evident disease in the pituitary area. Many CT appearances are shared by more than one pathological entity; few are specific. However, if the CT findings are viewed in the light of the clinical presentation, a pathological diagnosis is possible in a large proportion of cases. Angiography is valuable; not only to exclude lesions of vascular origin, or show neovascularity, but also to demonstrate the relationship of the internal carotid arteries to the sphenoidal sinus prior to transsphenoidal surgery.