Development of a CD28/CD86 (B7-2) Binding Assay for High Throughput Screening by Homogeneous Time-Resolved Fluorescence

CD28 has been demonstrated to provide the major costimulatory signal for CD4-positive T cells. Ligation with its natural ligands CD80 (B7-1) and CD86 (B7-2) leads to signals during activation that are required for the production of interleukin-2, and this process has been implicated in the regulation of T-cell anergy and programmed cell death. This article describes the assay development, assay validation, and primary screening for small molecule antagonists of this interaction, which could be potential drug candidates. The assay uses homogeneous time-resolved fluorescence based on energy transfer from excited europium ions to cross-linked allophycocyanin, which then subsequently emits a fluorescent signal. An "indirect" approach was taken, whereby the cross-linked allophycocyanin (XL665) is covalently linked to an antihuman antibody that binds to a human immunoglobulin (Ig) domain fused to CD28. The CD86 that is expressed as a fusion protein with a rat Ig domain is bound to biotinylated sheep antirat antibody, which is complexed with streptavidin-europium cryptate. This "cassette" format facilitates the development of related assays using CTLA-4 in place of CD28 and/or CD80 in place of CD86, allowing easy determination of the selectivity of active compounds. When the CD28 and CD86 are in close proximity (i.e., bound), there is a specific time-resolved emission at 665 nm that is largely absent in either unbound partner. Experiments to optimize the reagent concentrations, incubation time, solvent effects and quench effects by colored compounds are discussed, as are the results from robustness testing and data from primary screening.

Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer

PURPOSE

To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

MATERIALS AND METHODS

IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.

RESULTS

Scores of "5" were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of "5" were more predictive than resident scores of "5" (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of "5" included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).

CONCLUSION

Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

Unknown ESUR cases 2004

The authors present 14 cases from the film interpretation session of the 11th annual meeting of the European Society of Urogenital Radiology presented in September, 2004. The cases demonstrate the imaging findings, differential diagnoses, and clinical relevance of a wide variety of genitourinary tract diseases. The cases include examples of benign and malignant urinary tract neoplasms, inflammatory processes, vascular diseases, traumatic injuries, and congenital anomalies.

Multislice CT urography: state of the art

Recent improvements in helical CT hardware and software have provided imagers with the tools to obtain an increasingly large number of very thin axial images. As a result, a number of new applications for multislice CT have recently been developed, one of which is CT urography. The motivation for performing CT urography is the desire to create a single imaging test that can completely assess the kidneys and urinary tract for urolithiasis, renal masses and mucosal abnormalities of the renal collecting system, ureters and bladder. Although the preferred technique for performing multislice CT urography has not yet been determined and results are preliminary, early indications suggest that this examination can detect even subtle benign and malignant urothelial abnormalities and that it has the potential to completely replace excretory urography within the next several years. An important limitation of multislice CT urography is increased patient radiation exposure encountered when some of the more thorough recommended techniques are utilized.

Targeting human Ep-CAM in transgenic mice by anti-idiotype and antigen based vaccines

Anti-idiotypic antibodies (anti-Id) as surrogate TAAs have been shown to induce immunity against tumours in animals and humans. SM262 is a human monoclonal anti-Id raised against MAb 17-1A recognising Ep-CAM. Plasmids encoding the variable regions of SM262 with either murine or human Fc regions, both with and without fusion to GM-CSF were constructed. DNA was delivered by gene gun to C57BL/6 (wt) mice and mice expressing the transgene for human Ep-CAM (tg). The immunogenicity of anti-Id DNA constructs, anti-Id protein and Ep-CAM DNA vaccines was compared. SM262 plasmids induced antibodies (Abs) inhibiting MAb 17-1A binding to SM262 as well as recognising Ep-CAM in wt and tg mice. Fusion to GM-CSF evoked significantly higher Ab titres, whereas a xenogeneic Fc region had no significant effect. The highest Ab titres were elicited by protein immunisation. The original Ag was superior as compared to the anti-Id vaccines in wt but not tg mice in terms of Ab induction. A weak Ep-CAM-specific cytotoxic response was induced in wt but not tg mice. The data suggest that B cell tolerance to Ep-CAM can be circumvented by anti-Id DNA, anti-Id protein as well as Ep-CAM DNA immunisation. Fusion of GM-CSF to anti-Id increased the magnitude of the immune response with no requirement of a foreign Fc domain. Furthermore, no superiority of Ep-CAM as compared to anti-Id DNA vaccine was noted in tg mice and protein immunisation induced a more potent humoral response than DNA. The results might have implications for the design of future vaccine trials using Ep-CAM as a target structure.

Modeling the spread of annual influenza epidemics in the U.S.: the potential role of air travel

The role of air travel in the global spread of influenza has been the subject of a significant body of research, but this question has yet to be explored within the U.S. The goal of this research is to explore whether knowledge of U.S. air travel patterns and volumes leads to better forecasting of epidemics. We report the results of a series of simulations for the 1998-1999 through 2000-2001 influenza seasons using a standard compartmental model coupled with air transportation data. These preliminary results suggest that air travel may play an important role in the spread of annual influenza within the U.S., particularly in cities with large air travel volumes.

Use of locked nucleic acid oligonucleotides to add functionality to plasmid DNA

The available reagents for the attachment of functional moieties to plasmid DNA are limiting. Most reagents bind plasmid DNA in a non-sequence- specific manner, with undefined stoichiometry, and affect DNA charge and delivery properties or involve chemical modifications that abolish gene expression. The design and ability of oligonucleotides (ODNs) containing locked nucleic acids (LNAs) to bind supercoiled, double-stranded plasmid DNA in a sequence-specific manner are described for the first time. The main mechanism for LNA ODNs binding plasmid DNA is demonstrated to be by strand displacement. LNA ODNs are more stably bound to plasmid DNA than similar peptide nucleic acid (PNA) 'clamps' for procedures such as particle-mediated DNA delivery (gene gun). It is shown that LNA ODNs remain associated with plasmid DNA after cationic lipid-mediated transfection into mammalian cells. LNA ODNs can bind to DNA in a sequence-specific manner so that binding does not interfere with plasmid conformation or gene expression. Attachment of CpG-based immune adjuvants to plasmid by 'hybrid' phosphorothioate-LNA ODNs induces tumour necrosis factor-alpha production in the macrophage cell line RAW264.7. This observation exemplifies an important new, controllable methodology for adding functionality to plasmids for gene delivery and DNA vaccination.

Forecasting the geographical spread of smallpox cases by air travel

Instituting air travel restrictions to slow the geographical spread of smallpox cases would have significant consequences and present serious logistical concerns. Public health decision makers must weigh the potential benefits of such restrictions against their negative impact. The goal of this research is to provide a basic analytical framework to explore some of the issues surrounding the use of air travel restrictions as a part of an overall containment strategy. We report preliminary results of a compartmental model for the inter-city spread of smallpox cases resulting from US domestic air travel. Although air traffic can be halted within hours as was shown following the terrorist attacks of 11 September 2001, these results suggest that the consequences of halting domestic air travel may not be outweighed by public health benefits.

Differential roles of IL-16 and CD28/B7 costimulation in the generation of T-lymphocyte chemotactic activity in the bronchial mucosa of mild and moderate asthmatic individuals

BACKGROUND

IL-16 is an important T-cell chemotactic cytokine in asthmatic airways; its release from allergen-stimulated bronchial mucosa in mild asthma has been shown to be dependent on CD28/B7 costimulation.

OBJECTIVE

We have extended our previous studies to investigate the role of IL-16 and CD28/B7 costimulation in T-lymphocyte chemotactic activity (TLCA) released from the bronchial mucosa in more severe asthma.

METHODS

TLCA was determined in the supernatants of induced sputum and allergen-stimulated bronchial mucosal explants from healthy volunteers and volunteers with mild and moderately severe asthma by means of a Boyden chamber technique. The contribution of IL-16 to the activity was evaluated through use of a neutralizing monoclonal antibody; the contribution of CD28/B7 costimulation to allergen-induced release of TLCA was determined through use of CTLA4-Ig fusion protein and neutralizing monoclonal antibodies to CD80 (B7.1) and CD86 (B7.2).

RESULTS

Induced sputum and unstimulated explants from asthmatic subjects generated significant spontaneous TLCA (P <.05). Both mild and moderate asthmatic explants showed significantly elevated Dermatophagoides pteronyssinus -induced release of TLCA, but only in mild asthma could sputum and allergen-stimulated explant TLCA be inhibited by anti-IL-16 (median inhibition, 39% and 59%; P <.05). In addition, allergen released significant quantities of IL-16 from mild asthmatic explants (P <.05) but not from moderate asthmatic explants. Antibodies to the CD28 counter-ligands CD80 and CD86 inhibited allergen-induced release of TLCA in mild asthmatic explants by 94% (P <.05) and 62%, but TLCA release from moderate asthmatic explants was unaffected by CTLA4-Ig.

CONCLUSION

These results show that TLCA release in moderate asthmatic airways, in contrast to mild asthmatic airways, is not dependent on CD28/B7 costimulation and does not involve IL-16.

Effectiveness of abdominal compression during helical renal CT

RATIONALE AND OBJECTIVES

The authors performed this study to assess the effect of abdominal compression on opacification and distention of the proximal renal collecting system during helical computed tomography (CT).

MATERIALS AND METHODS

Abdominal compression was applied during helical CT in 31 patients who were scanned 150 and 300 seconds after initiating a dynamic bolus injection of contrast material. Two reviewers assessed renal collecting system opacification and measured the maximal short-axis diameter of the collecting system at three locations: the upper pole, the lower pole, and the proximal ureter. A similar evaluation was performed in a control group of 29 patients who underwent CT without compression at 300 seconds after initiating the injection of contrast material.

RESULTS

Both reviewers noted collecting system opacification at all locations in 52 of 56 noncompressed collecting systems scanned at 300 seconds, 57 of 59 compressed collecting systems scanned at 300 seconds, but only 26 of 59 compressed collecting systems scanned at 150 seconds. Measured collecting system distention was statistically significantly greater at 300 seconds in patents who received compression than in patients who did not (P = .0013). For patients who received compression, measured collecting system distention was statistically significantly greater on scans obtained at 300 seconds than on scans obtained at 150 seconds (P = .0001).

CONCLUSION

Abdominal compression during renal helical CT produces a detectable increase in renal collecting system distention. In patients who receive compression, scanning at 300 seconds rather than at 150 seconds results in greater collecting system distention and more consistent opacification.

An element within the 5' untranslated region of human Hsp70 mRNA which acts as a general enhancer of mRNA translation

The untranslated regions of mRNAs encoding heat-shock proteins have been reported to contain elements important to the post-transcriptional regulation of these key components of the stress response. In this report we describe an element from the 5'UTR of human Hsp70 mRNA that increases the efficiency of mRNA translation. Cloning of this region upstream of the coding sequence of two different reporter genes (firefly luciferase and chloramphenicol acetyltransferase) increases expression of the reporter under normal cell culture conditions by up to an order of magnitude. This effect was observed in three different promoter contexts (HSP, SV40 and CMV) and in six cell lines. The increase in protein production is not accompanied by any alteration in mRNA levels, suggesting that the element facilitates translation. 5' or 3' truncated sequences are ineffective in enhancing reporter expression, suggesting that the activity arises from the secondary structure of the element, rather than from some smaller defined motif. Computer analysis of this region revealed that it is able to form stable secondary structures (DeltaG approximately -292.6 kJ x mol(-1)). The Hsp70 element does not seem to act as an internal ribosome entry site. Incorporation of the sequence into plasmids used for DNA vaccination produces increased antibody responses, confirming that the sequence is functional in primary cells. These data suggest that the 5'UTR of human Hsp70 mRNA plays an important role in determining Hsp70 expression levels, and that it contains an element of general utility in enhancing recombinant protein expression systems.

How well does applicant rank order predict subsequent performance during radiology residency?

RATIONALE AND OBJECTIVES

Residency selection committees expend substantial time and resources on assessing the quality of residency applicants to derive an appropriate rank order for the National Residency Matching Program. The authors determined whether there is a relationship between the rank number or rank percentile of applicants selected for a residency training program and subsequent radiology residency performance.

MATERIALS AND METHODS

Records of radiology residents completing their residency between 1991 and 1998 were reviewed. Available rank numbers and rank percentiles for each resident were compared with subsequent performance, as assessed subjectively by 4th-year radiology rotation evaluation forms and retrospective recall of four senior faculty members and objectively by numerical and percentile scores on the written portion of the American Board of Radiology (ABR) examinations. Correlation coefficients were obtained for each comparison.

RESULTS

Rank number and rank percentile were not significantly correlated with 4th-year resident rotation evaluations or ABR written examination scores or percentiles. A small correlation existed between rank order and retrospective evaluation of resident performance by the four senior faculty.

CONCLUSION

Applicant rank number and rank percentile do not correlate with subsequent radiology residency performance as assessed on rotation evaluation forms or the ABR written examinations.

GRID: a novel Grb-2-related adapter protein that interacts with the activated T cell costimulatory receptor CD28

Adapter proteins such as Grb2 play a central role in the formation of signaling complexes through their association with multiple protein binding partners. These interactions are mediated by specialized domains such as the well-characterized Src homology SH2 and SH3 motifs. Using yeast three-hybrid technology, we have identified a novel adapter protein, expressed predominantly in T lymphocytes, that associates with the activated form of the costimulatory receptor, CD28. The protein is a member of the Grb2 family of adapter proteins and contains an SH3-SH2-SH3 domain structure. A unique glutamine/proline-rich domain (insert domain) of unknown function is situated between the SH2 and N-terminal SH3 domains. We term this protein GRID for Grb2-related protein with insert domain. GRID coimmunoprecipitates with CD28 from Jurkat cell lysates following activation of CD28. Using mutants of CD28 and GRID, we demonstrate that interaction between the proteins is dependent on phosphorylation of CD28 at tyrosine 173 and integrity of the GRID SH2 domain, although there are also subsidiary stabilizing contacts between the PXXP motifs of CD28 and the GRID C-terminal SH3 domain. In addition to CD28, GRID interacts with a number of other T cell signaling proteins, including SLP-76 (SH2 domain-containing leukocyte protein of 76 kDa), p62dok, and RACK-1 (receptor for activated protein kinase C-1). These findings suggest that GRID functions as an adapter protein in the CD28-mediated costimulatory pathway in T cells.

Comparison of nephrographic with excretory phase helical computed tomography for detecting and characterizing renal masses

OBJECTIVE

A retrospective study was performed to compare nephrographic phase (NP) with excretory phase (EP) renal helical computed tomographic (CT) images with respect to detection of renal masses 10 mm or more in diameter, and reviewer confidence in mass characterization.

METHODS

Two reviewers evaluated 39 renal helical CT examinations. All masses measuring 10 mm or more in maximal diameter were classified as simple cysts, complex cysts, solid lesions, or indeterminate lesions. Reviewers graded their confidence in the characterization of the masses and decided whether the NP or EP contrast-enhanced images were superior.

RESULTS

The 2 reviewers confidently characterized 71 (reviewer 1) and 65 (reviewer 2) of 72 detected masses 10 mm or more in diameter on NP images and 70 (reviewer 1) and 67 (reviewer 2) of 71 detected masses on EP images. There was strong agreement between the 2 sets of images in respect to the characterization of renal masses (kappa = 1.00 and 0.86). Only one mass (a focus of acute pyelonephritis) was not detected by either reviewer on EP images. Collecting system artifact degraded the quality of the EP image in images from only 1 patient.

CONCLUSION

Although EP images are often aesthetically inferior to NP images, use of EP images results in a similar rate of detection and confidence in characterization of renal masses measuring 10 mm or more in diameter.

Utility of routine trauma CT in the detection of bladder rupture

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the frequency with which routine computed tomography (CT) fails to depict bladder rupture, the potential utility of delayed CT scans, and whether these findings might be useful in determining which patients may require subsequent cystography.

MATERIALS AND METHODS

Cystograms and abdominal and pelvic CT scans of 54 patients with blunt trauma and in whom bladder rupture was clinically suspected were retrospectively reviewed. Blind readings of CT scans were performed by two genitourinary radiologists. Cystograms were used as the standard.

RESULTS

Cystograms depicted bladder rupture in 10 patients. On CT scans, extravesical fluid was depicted in all three patients with intraperitoneal bladder rupture (although only a small amount of pelvic intraperitoneal fluid was present in two of these patients), in all seven patients with extraperitoneal bladder rupture, and in 32 of the 44 patients without bladder injury. Contrast material had been excreted into the bladder at the time of the initial or delayed CT in eight patients with bladder rupture; however, extravasation was identified in only four of the eight. In two of the four patients without extravasation, the bladder was distended at the time of CT. No bladder injuries were found in the 12 patients in whom pelvic fluid was not identified on CT scans.

CONCLUSION

The absence of pelvic fluid on a trauma CT scan indicates that bladder rupture is unlikely. Even when a partially opacified bladder is passively distended, bladder injury may be present despite the absence of contrast material extravasation.

Molecular characterization and applications of recombinant scFv antibodies to CD152 co-stimulatory molecule

Recombinant human monoclonal antibodies against CD152 have been generated by selecting a synthetic phage scFv library with purified CD152-Ig fusion protein. Sixteen scFv fragments were isolated which specifically react with CD152 by enzyme-linked immunoabsorbent assay (ELISA) and Western blot resulting in their clustering into two groups recognizing different antigenic determinants. One group of scFvs (#3, #13, #40, #44, #47, #51, #57, #80 #83) recognized an epitope on CD152 dimer whereas another group (#15, #18, #31, #35, #54, #72, #81) recognized an epitope on both dimeric and monomeric CD152 molecule suggesting their possible use in understanding the subunit structure of CD152 which is still controversial. Sequencing of the VH genes revealed that all the scFvs belonged to the VH3 gene family but they were different in CDR3 length and composition. It was possible to correlate specific CDR3 sequences with reactivity of the two groups of scFvs. Four scFvs, #3, #40, #81 and #83, each representative of one specific CDR3, were selected for further analysis. Competition ELISA experiments showed that they recognize CD152 in its native configuration and bound to different epitopes from the CD80/CD86 interaction site. The scFvs were able to stain human T lymphocytes stimulated either with anti-CD3 and CD28 antibodies or PHA, PMA and ionomycin by cytofluorimetry suggesting that they can be useful reagents for monitoring the kinetics of surface-bound and intracellular CD152.

A lack of evidence for down-modulation of CD3 zeta expression in colorectal carcinoma and pregnancy using multiple detection methods

Loss of the T cell receptor-associated CD3 zeta chain has been proposed as a possible mechanism of the acquired immunosuppression in both tumour-bearing hosts, and in symptomatic patients with HIV infection. However, other reports suggest that the zeta-chain loss may in part be caused by protease activity of contaminating phagocytes ex vivo. Using flow cytometry and Western blot analysis on highly purified T cells, and ensuring adequate addition of protease inhibitors, we have studied the expression of CD3zeta on peripheral blood T cells from patients with colorectal carcinoma, and compared these with normal controls, and pregnant donors, as a further example of an immunocompromised state. Immunohistochemistry was performed on tumour sections from patients with colorectal carcinoma to measure CD3zeta expression in tumour infiltrating T cells, and compared with normal mucosa and tonsil. Using these three approaches, our data provide no evidence for downregulation of CD3zeta chain expression either in colorectal carcinoma or pregnancy and suggest that this explanation is unlikely to fully account for the reduced T cell function associated with these conditions in all patients.

Occurrence of adverse reactions to gadolinium-based contrast material and management of patients at increased risk: a survey of the American Society of Neuroradiology Fellowship Directors

RATIONALE AND OBJECTIVES

The authors attempted to determine the frequency and severity of adverse reactions to gadolinium-based magnetic resonance (MR) contrast agents and to identify strategies for management of patients at increased risk.

MATERIALS AND METHODS

American Society of Neuroradiology program directors were surveyed about adverse reactions at their institutions to gadolinium-based contrast agents, the contrast agents responsible, and the management of patients with allergy-like reactions to iodinated or gadolinium-based agents who required MR contrast agent administration.

RESULTS

Fifty-three (50.5%) surveys were received from 105 centers. Of 687,255 gadopentetate dimeglumine injections, 314 (0.046%) nonallergic reactions and 107 (0.016%) mild, 28 (0.004%) moderate, and five (0.001%) severe allergy-like reactions occurred. Of 74,275 gadodiamide injections, 11 (0.015%) nonallergic and 12 (0.016%) mild allergy-like reactions occurred. Of 64,005 gadoteridol administrations, 171 (0.267%) nonallergic reactions and 49 (0.077%) mild, 29 (0.047%) moderate, and 11 (0.017%) severe allergy-like reactions occurred. Twenty-six departments took no precautions for patients with previous allergy-like reactions to iodinated contrast material. Nineteen did not premedicate patients who previously had reactions to gadolinium-based agents before repeat administration of MR contrast agents.

CONCLUSION

Although MR contrast agents are safe, adverse reactions occur. Many centers have not adopted policies for the OFF

Diagnosis and staging of ovarian cancer: comparative values of Doppler and conventional US, CT, and MR imaging correlated with surgery and histopathologic analysis--report of the Radiology Diagnostic Oncology Group

PURPOSE

To determine the optimal imaging modality for diagnosis and staging of ovarian cancer.

MATERIALS AND METHODS

Two hundred eighty women suspected to have ovarian cancer were enrolled in a prospective study before surgery. Doppler ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging were used to evaluate the mass; conventional US, CT, and MR imaging were used to stage spread.

RESULTS

All three modalities had high accuracy (0.91) for the overall diagnosis of malignancy. In the ovaries, the accuracy of MR imaging (0.91) was higher than that of CT and significantly higher than that of Doppler US (0.78). In the extraovarian pelvis and in the abdomen, conventional US, CT, and MR imaging had similar accuracies (0.87-0.95). In differentiation of disease confined to the pelvis from abdominal spread, the specificity of conventional US (96%) was higher than that of CT and significantly higher than that of MR imaging (88%), whereas the sensitivities of MR imaging (98%) and CT (92%) were significantly higher than that of conventional US (75%).

CONCLUSION

MR imaging is superior to Doppler US and CT in diagnosis of malignant ovarian masses. There is little variation among conventional US, CT, and MR imaging as regards staging.

Orthotopic neobladder reconstruction: findings on excretory urography and CT

OBJECTIVE

The excretory urographic and CT appearance of orthotopic ileal neobladder reconstruction after cystectomy and its complications are described.

MATERIALS AND METHODS

We retrospectively reviewed the excretory urograms and CT scans of 32 patients (29 men and three women, 35-76 years old) with transitional cell carcinoma of the bladder who underwent orthotopic neobladder reconstruction with anastomosis to the native urethra after cystectomy. The radiologic review consisted of 25 excretory urograms in 20 patients and 37 CT scans in 21 patients.

RESULTS

On excretory urography, the afferent segment of the neobladder was identified as a contrast-filled structure in all 20 patients, and was located in the right lower quadrant in 18 (90%). On CT, the afferent segment and the neobladder were identified in all 21 patients. Delayed imaging performed after initial scanning in 12 (57%) of 21 patients was helpful for revealing detailed anatomy such as the ureteral-afferent limb anastomoses. Complications occurred in two patients and were caused by a lymphocele in one and a urine leak from the neobladder in the other. In six other patients we found evidence of recurrent or metastatic tumor or both: two had local pelvic recurrence and pelvic nodal metastases, two other patients had metastatic nodal disease, one patient had a malignant distal ureteral stricture, and the sixth patient had distant osseous metastases.

CONCLUSION

Orthotopic neobladder reconstruction after cystectomy has a characteristic appearance on both excretory urography and CT. Knowledge of this appearance and the altered anatomy is useful to recognize complications and tumor recurrence. Delayed images during excretory urography and CT are useful to define the ureteral-afferent limb anastomosis with the neobladder and also to differentiate between postoperative collections.

Impact of social interactions in the community on the transmission of tuberculosis in a high incidence area

BACKGROUND

Tuberculosis (TB) is transmitted by close contact with an infectious person. It is assumed that close contact occurs amongst household members and that contact outside the house is "causal" and does not play a major role in the transmission of TB.

METHODS

This study was conducted in an impoverished area with a high incidence of TB and a low HIV seropositive prevalence. Thirty three households with 84 TB patients were identified between February 1993 and April 1996 and the transmission of TB was studied by combining Mycobacterium tuberculosis fingerprinting with in depth sociological interviews.

RESULTS

Forty two strain genotypes were identified in the 84 patients. In 15 households all the patients had identical strains, in nine households all the patients had different strains, and in nine households some patients had identical strains and one had a different strain. In 26 houses at least one patient had a strain which formed part of a larger community cluster and in 12 of these households the patient(s) had contact with a community member who had the identical strain. In 58% of the cases the contact took place while drinking in social groups.

CONCLUSION

In high incidence areas contact outside the household may be important for the transmission of TB. This contact often takes place during recreation which, in the case of this study of impoverished people, consisted of drinking in social groups. Social interaction patterns should be studied and understood for effective implementation of control strategies.

Aortic enhancement during abdominal CT angiography: correlation with test injections, flow rates, and patient demographics

OBJECTIVE

The goal of our study was to determine the effect of contrast material injection rate and patient demographic variables on vascular enhancement for abdominal CT angiography and compare test injection results with actual patterns of vascular enhancement.

SUBJECTS AND METHODS

One hundred twenty-five patients underwent abdominal CT angiography. For each patient, CT attenuation values (Hounsfield units) of the aorta were determined before and after IV contrast administration, every 3 sec between 21 and 60 sec. A peak aortic enhancement value and the time needed to reach peak and aortic enhancement thresholds of 150 and 200 H were determined. All patients received 150 ml of nonionic contrast material at 3 ml/sec in 25 patients and 4 ml/sec in 100 patients. A test injection of 15 ml was used to compute a scan delay in 46 patients. Patient age, sex, weight, injection rate, and test injection results were compared with vascular enhancement patterns.

RESULTS

For the 125 patients, the mean aortic enhancement at each time point was greater than 150 H. Patient weight was inversely correlated (r2 = -.62) with aortic enhancement. The test injection did not accurately predict actual aortic enhancement peak value or time. Test injection delay time was significantly correlated with time to reach aortic enhancement thresholds of 150 and 200 H. The 4 ml/sec rate resulted in a higher peak aortic enhancement (320+/-58 H versus 281+/-49 H) (mean +/- SD, p < .01) that was reached quicker than with the 3 ml/sec injection rate (45+/-5 sec versus 52+/-5 sec) (p < .01). Injecting at 4 ml/sec resulted in greater aortic enhancement values at 24-45 sec, whereas 3 ml/sec produced significantly better aortic enhancement at 54-60 sec.

CONCLUSION

The test injection correlated better with time to reach specific aortic enhancement thresholds than with time to peak aortic enhancement. For a given amount of contrast material, faster injection rates resulted in greater vascular enhancement that occurred earlier.

Functional analysis of the T-cell-restricted protein tyrosine kinase Txk

T lymphocytes express a range of tyrosine kinases that are involved in signalling processes driving cell activation, proliferation and differentation. Two tyrosine kinases expressed only in T cells, the Itk/Emt and Txk gene products, are members of the Tec family of kinases. The role of Tec kinases in cellular function is poorly understood, although a Tec kinase specific to B cells, Btk, is essential for B-cell development. To explore the contribution of the T-cell-specific Tec kinases to lymphocyte function, we have expressed human Txk in the baculovirus system and conducted the first characterization of its activity. We find that Txk exhibits a substrate preference in vitro quite distinct from that of the major T-cell kinases Lck and ZAP70, suggesting that Tec-family kinases might act on a distinct range of substrates. We also investigated the interactions of Txk with the cytoplasmic domains of the key signalling molecules CD3zeta, CD28 and CTLA4 and find that none of these are phosphorylated by Txk, nor are they ligands for the SH2 or SH3 domains of Txk. We conclude that it is unlikely that Txk has a role in the early signal transduction events associated with these key pathways controlling T-cell activation.

Helical CT evaluation of potential kidney donors: findings in 154 subjects

OBJECTIVE

The purpose of our study was to assess renal helical CT (RHCT) as the primary imaging technique in the evaluation of potential kidney donors.

SUBJECTS AND METHODS

Unenhanced and enhanced (3-mm collimation) RHCT was performed in 154 kidney donors using 125-150 ml of i.v. contrast material at an injection rate of 3 or 4 ml/sec and a pitch of 1.3-2. Scans were reconstructed at 1.5-mm intervals for a three-dimensional image. RHCT images were compared with the results of renal arteriography (RA) (50 subjects) and surgery (117 subjects).

RESULTS

CT and surgical findings agreed in 95% of patients (111/117), with five cases of missed accessory arteries (all < 2 mm in diameter) and one case of a missed early division of the main artery. In the 50 subjects who underwent CT and RA, imaging revealed concordance in 96% of 100 kidneys. One small accessory artery was not detected by CT (origin from the common iliac artery). RA did not detect accessory arteries in three subjects. All 22 kidneys with early dividing main arteries (< 1.5 cm from the aortic origin) were identified by both RHCT and RA. Axial and three-dimensional CT images were complementary: five small accessory arteries were seen well only on the axial sections, whereas four early dividing arteries and two cases of renal artery stenosis were prospectively identified only on the three-dimensional images. Twenty-five renal vein anomalies were detected only by CT. In the full series of 154 subjects, nonvascular renal findings included renal calculi (n = 11), cysts (n = 12), duplicated ureters (n = 6), horseshoe kidney (n = 1), and pelvic kidney (n = 1).

CONCLUSION

RHCT can be the primary imaging technique in the assessment of potential kidney donors, reducing the number of examinations as well as the risk and cost of imaging in these subjects.

Local reactions after injection of iodinated contrast material: detection, management, and outcome

RATIONALE AND OBJECTIVES

The authors assessed the frequency, sequelae, and risk factors of extravasation of intravenously administered iodinated contrast media.

MATERIALS AND METHODS

All patients with local reactions after intravenous injection of contrast media between November 1994 and December 1996 were studied. Comparison was made with data obtained from a control group of 100 patients with no local reactions who underwent contrast material-enhanced computed tomography (CT).

RESULTS

Local reactions were reported in 56 (0.25%) of 22,254 patients who received intravenous injections of iodinated contrast media. Fifty-one patients experienced extravasation, and five patients experienced local irritation in the absence of clinically detectable extravasation. Extravasation occurred during CT (n = 46), urography (n = 4), and venography (n = 1). Contrast material was nonionic in 37 cases and conventional ionic in 14 cases of extravasation. Extravasated volumes exceeded 30 mL in 22 patients and 100 mL in six patients. Forty-five (80%) of 56 patients with local reactions had complete resolution of symptoms within 24 hours. Only four patients had symptoms for more than 48 hours. No surgery was required. Compared with the control group, patients with extravasation were significantly more likely to have been injected with small-bore catheters (21 or 22 gauge) and to have been injected at low or high rates.

CONCLUSION

Symptoms of contrast medium extravasation usually resolve quickly. In patients with extravasation, injections are more likely to have been performed with techniques that vary from normal practice.

Liability issues associated with PRK and the excimer laser

Given the elective nature of photorefractive keratectomy (PRK), the high expectations of patients, and misconceptions of the general public about refractive surgery, the use of the excimer laser for PRK opens the door to new liability risks for ophthalmologists and, in the comanagement environment, referring optometrists. The authors discuss informed consent, marketing, comanagement, and off-label use guidelines and protocols to help protect ophthalmologists against claims and better defend those that might arise.

Liver metastases: early detection based on abnormal contrast material enhancement at dual-phase helical CT

PURPOSE

To assess whether contrast material enhancement findings on computed tomographic (CT) scans are useful in determination of the risk for development of hepatic metastases.

MATERIALS AND METHODS

Dual-phase helical CT scans were obtained in 80 patients with nonhepatic cancer and no hepatic metastases visible at CT. Attenuation was measured on scans obtained at 25 and 40 seconds. Peak liver attenuation was determined in all cases. Unenhanced scans were obtained in 35 patients. The ratio of liver attenuation at 25 and 40 seconds to peak liver attenuation, liver enhancement values at 25 and 40 seconds, and ratio of liver enhancement at 25 and 40 seconds to peak liver enhancement were determined.

RESULTS

Liver metastases developed during 18-month follow-up in 22 patients. The 25- and 40-second liver enhancement values and the liver enhancement and attenuation ratios were higher in these patients than in those who did not develop metastases (P < .01). Enhancement values and ratios were more accurate than densitometric measurements for predicting development of metastases. Use of an optimal threshold (0.40 or greater) for the 40-second enhancement ratio resulted in a sensitivity of 75%, specificity of 96%, and overall accuracy of 89%.

CONCLUSION

CT measurements may help in the prediction of risk for subsequent development of hepatic metastases.

Sociological and anthropological factors related to the community management of tuberculosis in the Western Cape communities of Ravensmead and Uitsig

OBJECTIVE

To determine the sociocultural understanding of tuberculosis among patients and their household members.

DESIGN

Qualitative descriptive study.

SETTING

Two adjacent Western Cape suburbs with a population of approximately 35,000, a tuberculosis incidence of > 1,000/100,000 and a surface area of 2.42 km2.

SUBJECTS

Twenty-three adult patients on treatment for tuberculosis and their adult household members.

INTERVENTIONS

None.

METHODOLOGY

Consecutive selected adult tuberculosis patients and their household members were interviewed with an open-ended interview schedule. General household and community conditions and non-verbal responses were recorded.

RESULTS

There were relatively affluent but also severely deprived households with severe overcrowding. Substance abuse was common. Patients had limited understanding and knowledge about health, hygiene and the cause of tuberculosis. There was a perception of both physical and social distance between patients and health care providers. All patients relied exclusively on the conventional biomedical curative approach of the medical system to deal with tuberculosis.

Iodinated contrast material in uroradiology. Choice of agent and management of complications

Many conditions seen by urologists require imaging examinations with iodinated radiographic contrast material as a key part of the primary evaluation of the patient. A basic understanding of contrast media, risks of administration, choice of agents, and premedication regimens for high-risk patients, is beneficial in helping patients prepare for their examinations. Urologists may be the primary physicians administering contrast material or may be working with radiologists in the care of patients receiving contrast agents. Because contrast reactions may occur unexpectedly, even during examinations in which the agents are not given intravenously, urologists should be able to recognize and treat the various types of adverse reactions.

Difference in global hepatic enhancement assessed by dynamic CT in normal subjects and patients with hepatic metastases

PURPOSE

Our goal was to determine if there are differences in liver densitometry parameters using helical CT between normal subjects and subjects with liver metastases.

METHOD

One-hundred fifty subjects (64 with normal livers and 86 with CT-visible hepatic metastases) underwent dual phase helical scanning of the liver. Images were obtained in the "arterial" (early) and "venous" (late) phases of hepatic enhancement. Densitometry measurements were obtained from the liver (distinct from obvious lesions or vessels) and aorta at 25, 40, 75, and 90 s. Enhancement values at the same time points were calculated in 73 subjects in whom noncontrast images of the liver were available. A peak liver densitometry value was also determined. Several ratios were determined for each time point: the liver/aortic ratio (L/A), liver/liver peak ratio (L/P), liver enhancement/aortic enhancement ratio (LE/AE), and liver enhancement/liver peak enhancement ratio (LE/LPE). The degree of tumor burden in the hepatic metastatic group was assessed in each case.

RESULTS

Values for L/A, L/P, LE/AE, and LE/LPE at 25 and 40 s were significantly (p < 0.05) higher in the liver metastases group than the normal liver group. Enhancement ratios were even more elevated in breast cancer, which can have hypervascular metastases. These CT parameters did not show significant differences when analyzed according to the degree of hepatic metastatic tumor burden. All densitometry parameters and ratios obtained at 75 and 90 s were not significantly different between the two groups.

CONCLUSION

In the early phase of bolus intravenous contrast agent administration, the visually normal portion of the liver parenchyma in patients with hepatic metastases enhances to a greater degree than the liver in normal subjects. This may reflect generalized increased hepatic arterial flow in tumor-bearing livers and has the potential to increase the sensitivity of CT for detection of hepatic metastases.

Lupus nephritis: predictive value of conventional and Doppler US and comparison with serologic and biopsy parameters

PURPOSE

To compare conventional and Doppler ultrasound (US) with clinical and biopsy parameters used to assess disease activity and outcome in lupus nephritis and to assess the predictive value of US.

MATERIALS AND METHODS

Thirty-four patients with lupus nephritis prospectively underwent laboratory and US analysis at the time of renal biopsy. US parameters were renal length, relative echogenicity, and resistive index (RI). Laboratory parameters were serum creatinine level, urinary protein level, and serum markers of disease activity. Biopsy parameters were activity index, chronicity index, and assessment of the tubulointerstitium of the kidney. Follow-up data were obtained in all patients for at least 1 year.

RESULTS

Ten patients with elevated RI (>0.70) had significantly (P <.05) higher chronicity indexes and creatinine levels than the 24 patients with a more normal RI. RI correlated significantly (P <.05) with creatinine level, chronicity index, and presence of interstitial disease. Only RI and chronicity index were statistically significant predictors of a poor renal outcome. Abnormalities at conventional US were not predictive of renal outcome. A normal RI predicted a better renal outcome whether or not creatinine level was elevated.

CONCLUSION

Renal Doppler US may be of greatest clinical utility when its results are apparently discordant with renal functional assessment by allowing identification of patients with higher likelihood of subsequent improvement or worsening of renal status.

Use of Doppler sonography for revealing hepatic artery stenosis in liver transplant recipients

OBJECTIVE

The goal of our study was to evaluate the use of duplex Doppler sonography for revealing hepatic artery stenosis (HAS) in patients who have undergone liver transplantation.

MATERIALS AND METHODS

Forty-six patients with spectral Doppler waveforms obtained from the hepatic artery and with subsequent arteriography were reviewed retrospectively. Arterial waveforms, resistive indexes (RIs), and systolic acceleration times (SATs) were evaluated by one reviewer who was unaware of the arteriographic findings. The mean interval between the two examinations was 2.8 days. Arteriograms that revealed a stenosis of greater than 50% were classified as abnormal.

RESULTS

Of the 46 patients, 21 (46%) had a significant stenosis. Patients who had HAS had significantly (p < .05) prolonged SATs (0.08 +/- 0.03 sec versus 0.06 +/- 0.02 sec) and reduced RIs (0.49 +/- 0.05 versus 0.66 +/- 0.05) compared with patients who did not have HAS. Optimal thresholds for HAS detection were RIs less than 0.55 and SATs greater than 0.08 sec. HAS was found in 14 of 15 patients who had both abnormal RIs and SATs. Of the remaining 31 patients, 12 had abnormal values for RI or SAT. Of these 12 patients, three had HAS. Thus, 19 patients had normal RIs and SATs; however, four of these patients were found to have an arterial stenosis. In our 46 patients, abnormal values for both RI and SAT were 67% sensitive and 96% specific for stenosis. When at least one abnormal value was found on Doppler imaging, sensitivity and specificity for stenosis were 81% and 60%, respectively.

CONCLUSION

Duplex Doppler imaging can noninvasively reveal HAS. Abnormal values for both RI and SAT proved to be a more accurate predictor of stenosis than either RI or SAT as independent parameters.

Treatment of adverse reactions to radiographic contrast media in adults

Prompt recognition and treatment can be invaluable in blunting an adverse response of a patient to radiographic contrast material and may prevent a reaction from becoming severe or even life-threatening. Radiologists and their staff should review treatment procedures regularly (at least annually) so that each staff in attendance can accomplish his or her role efficiently. Knowledge, training, and preparation are crucial in guaranteeing appropriate and aggressive therapy in the event of an adverse contrast-related event.

Assessment of renal function with computed tomographic densitometry measurements

RATIONALE AND OBJECTIVES

We assessed the relationship between multiple renal computed tomographic (CT) densitometry parameters and renal function.

METHODS

Three hundred seventy-three patients underwent standardized helical CT of the abdomen. The ratio of mean attenuation in the renal cortex to mean attenuation in the aorta (KAR), the products of mean renal cortical attenuation with CT-estimated renal volume (KVP), and the patient's weight (KWP) were derived from scans obtained 90 sec (n = 373) and 30 sec (n = 108) after initiation of intravenous contrast material administration. These densitometry parameters were compared with renal function measured by serum level of creatinine and creatinine clearance (CrCl).

RESULTS

Among the 373 patients in the study, we found statistically significant differences (p < .01) between the patients with normal renal function (CrCl > or = 60 ml/min, n = 300) and the patients with abnormal renal function (CrCl < 60 ml/min, n = 73) for the KAR, KVP, and KWP. The KAR was the parameter best correlated with CrCl and was an independent predictor of renal function from the patient's age, weight, and renal volume. Fifty-three patients with a KAR less than 1 had significantly worse renal function (CrCl = 60 +/- 21 ml/min) than the patients with a KAR greater than or equal to 1 (CrCl = 95 +/- 31 ml/min). Only 4% of patients with normal renal function had a KAR less than 1. A threshold value of KAR less than 1 had a sensitivity of 55%, a specificity of 96%, a positive predictive value of 75%, and a negative predictive value of 90% for predicting renal dysfunction. CT parameters obtained at 30 sec were less useful than parameters at 90 sec.

CONCLUSION

In patients undergoing clinically requested CT scanning, renal densitometry analysis can be used to depict patients with normal renal function; however, it has a high false-negative rate in depicting patients with diminished renal function.

Hepatic hemodynamic alterations after administration of oral CT contrast agents

PURPOSE

To assess the effects of oral computed tomography (CT) contrast agents on hepatic hemodynamics with duplex Doppler ultrasound (US).

MATERIALS AND METHODS

Thirty healthy subjects who fasted underwent duplex Doppler US of the hepatic artery and portal vein both before and after administration of oral CT contrast agents. Resistive indexes were determined for the hepatic arteries. Peak and mean velocity (centimeters per second) and mean diameter were calculated for the main portal vein.

RESULTS

Statistically significant elevation of the resistive index (P < .01) of the hepatic arteries was observed after ingestion of oral CT contrast agents. Increase in the mean resistive index at 15 minutes was 12% in the proper hepatic arteries and 20% in the intrahepatic arteries. There was a postprandial increase in mean portal venous flow compared with baseline levels (1,110 mL/min +/- 210 vs 940 mL/min +/- 140) (P < .05).

CONCLUSION

An elevation of hepatic artery resistance that is probably due to arterial vasoconstriction after ingestion of oral CT contrast agents can be observed with Doppler US. Hemodynamic changes in liver vasculature after ingestion of oral CT contrast agents may have as yet unknown implications for CT scanning of the liver.

Interactions of CD80 and CD86 with CD28 and CTLA4

CD80 and CD86 are cell surface glycoproteins expressed on a variety of professional APCs. They have attracted much attention due to their function as potent costimulators of T lymphocyte function through their interaction with CD28 and possibly CTLA4. Because inhibitors of this interaction may have therapeutic relevance in human autoimmune disease, we investigated the properties of linear peptides derived from conserved regions of CTLA4 and CD80 known to be essential for binding. None of these peptides were sufficient to bind ligand, nor did they act as potent competitive inhibitors. Conformationally constrained versions of the CTLA4 motif were also inactive. These results suggested that other parts of the proteins are important in determining binding, so a series of modified CD80 and CD86 molecules were constructed in an attempt to identify other binding determinants. Insertion of two residues between the two Ig domains of CD80 resulted in decreased affinity for CTLA4, but a similar mutation in CD86 was without effect. We also identified another asymmetry between CD80 and CD86 in that the V domain of CD86 but not that of CD80 is sufficient for CTLA4 binding. The CD86-V domain appears to have CTLA4 binding properties equivalent to that of intact CD86. These data illustrate a fundamental difference between these costimulatory molecules and suggest a mechanism by which they may be differentially recognized by receptors on the T cell surface.

Interactions of CD80 and CD86 with CD28 and CTLA4

CD80 and CD86 are cell surface glycoproteins expressed on a variety of professional APCs. They have attracted much attention due to their function as potent costimulators of T lymphocyte function through their interaction with CD28 and possibly CTLA4. Because inhibitors of this interaction may have therapeutic relevance in human autoimmune disease, we investigated the properties of linear peptides derived from conserved regions of CTLA4 and CD80 known to be essential for binding. None of these peptides were sufficient to bind ligand, nor did they act as potent competitive inhibitors. Conformationally constrained versions of the CTLA4 motif were also inactive. These results suggested that other parts of the proteins are important in determining binding, so a series of modified CD80 and CD86 molecules were constructed in an attempt to identify other binding determinants. Insertion of two residues between the two Ig domains of CD80 resulted in decreased affinity for CTLA4, but a similar mutation in CD86 was without effect. We also identified another asymmetry between CD80 and CD86 in that the V domain of CD86 but not that of CD80 is sufficient for CTLA4 binding. The CD86-V domain appears to have CTLA4 binding properties equivalent to that of intact CD86. These data illustrate a fundamental difference between these costimulatory molecules and suggest a mechanism by which they may be differentially recognized by receptors on the T cell surface.

Suspected obstructive pyelocaliectasis: Doppler ultrasonography compared with diuretic renal scintigraphy in proven cases

OBJECTIVE

To compare Doppler ultrasonography with diuretic renal scintigraphy in the differentiation of obstructive from nonobstructive pyelocaliectasis.

PATIENTS AND METHOD

The authors reviewed the findings of Doppler ultrasonography and diuretic renal scintigraphy performed over a 3-year period for 27 pyelocaliectatic kidneys (17 obstructed and 10 unobstructed) in 20 individuals ranging in age from 19 to 88 years. The kidneys were classified as "obstructed" or "unobstructed" on the basis of the resistive index as calculated from Doppler ultrasonographic results and as "obstructed", "unobstructed" or "indeterminate" on the basis of the clearance half-time determined from scintigraphic findings.

RESULTS

On the basis of scintigraphy, the obstruction status was indeterminate in 12 of the 27 kidneys. The data were analysed for sensitivity and specificity in two ways, first by classifying the kidneys with indeterminate obstruction status as "obstructed, " and then by excluding them from the analysis altogether. In both situations, the differences in sensitivity and specificity between Doppler ultrasonography and scintigraphy were not statistically significant (chi 2 test, p > 0.05). When the kidneys with indeterminate obstruction status were included in the obstructed category, the sensitivity and specificity of Doppler ultrasonography were 94% and 90% respectively and of scintigraphy 100% and 70% respectively; when the kidneys with indeterminate obstruction status were excluded, the sensitivity and specificity of Doppler ultrasonography were 83% and 89% respectively and of scintigraphy 100% and 78% respectively.

CONCLUSIONS

These results suggest that Doppler ultrasonography is comparable to diuretic renal scintigraphy in the work-up of potential obstructive pyelocaliectasis. Because grey-scale ultrasonography is usually performed before scintigraphy, a Doppler examination could be added at this stage, which might reduce the time necessary to establish the diagnosis.

Magnetic resonance imaging of the levator ani with anatomic correlation

OBJECTIVE

To define in women the anatomy of the levator ani muscle visible on magnetic resonance imaging (MRI) so these muscles can be studied in women with prolapse or incontinence.

METHODS

Multiplanar T1- and T2-weighted MRI was obtained of two female pelvic cadaver specimens, ages 25 and 33. One specimen was hemisected, with half sectioned in the axial plane and the other half in the coronal plane. The other specimen was sectioned in the coronal plane. Anatomic cross sections of these specimens were correlated with the cadaver MRI and MRI of living patients. One sagittal and two axial series of anatomic sections not imaged were also used for comparison.

RESULTS

Serial sagittal and axial MRI demonstrates the pubovisceralis ("pubococcygeus") muscle as it originates from the pubic bone, passes alongside the urethra, vagina, and rectum, and then dorsal to the anorectum. Its muscle bulk, attachment to the distal half of the vagina, and insertion between the internal and external anal sphincters can be seen on axial views. The origin of the iliococcygeus muscle at the arcus tendineus levator ani is seen in axial and coronal images. Coronal and sagittal images demonstrate the relative thickness and medial position of the pubovisceralis muscle compared with the thin, diaphragm-like lateral iliococcygeus muscle.

CONCLUSION

Magnetic resonance imaging of the cadaver pelvis demonstrates the detailed anatomy of the levator ani muscle. This is an important precursor to future research of the structure, bulk, and orientation of the levator ani in living women with prolapse.

Potential renal donors: comparison of conventional imaging with helical CT

PURPOSE

To assess helical computed tomography (CT) as a potential substitute for intravenous urography and renal angiography in the evaluation of living potential renal donors.

MATERIALS AND METHODS

Helical CT was performed in 32 potential donors both before and after administration of contrast material. Scans were reconstructed at 1.5-mm intervals for three-dimensional reconstructions. Helical CT images were blindly compared with urograms (n = 32) and renal angiograms (n = 24).

RESULTS

One small accessory artery was not depicted with helical CT, and angiography did not depict an accessory artery arising in proximity to the origin of the main renal artery. All eight kidneys with early dividing main arteries were identified with both helical CT and angiography. Three renal venous anomalies were depicted only with helical CT. Helical CT and urography equally depicted nonvascular findings.

CONCLUSION

Renal helical CT is a suitable replacement for intravenous urography and angiography in the assessment of living renal donors.