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P J Kenney

Publications and source records attributed to P J Kenney.

At least 19 recordsLinked to original sources
PubMed2001

Interactions between methylating and pyridyloxobutylating agents in A/J mouse lungs: implications for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis.

The tobacco-specific nitrosamine, 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone, is activated to lung DNA methylating and pyridyloxobutylating intermediates. It is likely that both pathways play a role in lung tumor initiation by this nitrosamine. Previous studies indicated that O(6)-methylguanine (O(6)-mG) persistence is critical for lung tumor formation in A/J mice. The model pyridyloxobutylating agent, 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (NNKOAc), enhanced the tumorigenic activity of a model methylating agent, acetoxymethylmethylnitrosamine (AMMN), presumably by increasing O(6)-mG persistence in lung DNA. We have been testing the hypothesis that the pyridyloxobutylation pathway increases the mutagenic activity of the DNA methylation pathway by preventing the repair of O(6)-mG by O(6)-alkylguanine-DNA alkyltransferase (AGT). In this study, we report that NNKOAc depletes AGT in lungs but not livers of A/J mice. The consequences of AGT depletion by NNKOAc were then compared with those observed with a known AGT inhibitor, O(6)-benzylguanine (O(6)-bG). NNKOAc and O(6)-bG had similar effects on the levels of AMMN-derived O(6)-mG at 4 and 96 h postinjection. This increase in O(6)-mG levels correlated to increased lung tumor multiplicity in animals simultaneously treated with AMMN (0.75 or 1 micromol) and NNKOAc or O(6)-bG. Only NNKOAc significantly increased lung tumor multiplicity at doses of 0.25 or 0.5 micromol AMMN. The results from these studies indicate that the pyridyloxobutylating agent, NNKOAc, can influence the tumorigenic activity of methylating agents in two ways. At low AMMN doses, the increase in tumor multiplicity is dominated by the additive tumorigenic properties of AMMN and NNKOAc. At higher AMMN doses, NNKOAc appears to enhance the tumorigenic activity of AMMN through enhanced depletion of the repair protein, AGT, leading to increased O(6)-mG persistence. It is likely that similar interactions are important for the organospecific effects of 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone.

Alkylating Agents↗
PubMed2000

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety).

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Abdominal Pain↗
PubMed2000

CT cystography: radiographic and clinical predictors of bladder rupture.

OBJECTIVE: Our goal was to identify radiographic and clinical variables that correlate with bladder rupture that may then be used as selection criteria for CT cystography in trauma patients. SUBJECTS AND METHODS: Hemodynamically stable trauma patients with hematuria were examined under standardized protocol with dynamic oral and i.v. contrast-enhanced CT of the abdomen and pelvis, followed immediately by CT cystography. CT cystography consisted of contiguous 5-mm axial scans of the pelvis after retrograde distention of bladder with 300-400 ml of 4% iodinated contrast material. Radiographic and clinical variables (pelvic fracture, pelvic fluid, intraabdominal visceral injury, degree of hematuria, hematocrit, units of blood transfused, base deficit, injury mechanism, seat belt use, sex, age) were assessed and statistically analyzed using the two-tailed Fisher's exact test and Wilcoxon's rank sum test. Positive and negative individual and multivariate predictors were analyzed. RESULTS: Of the 157 patients entered in our study, 12 (eight males and four females) had bladder rupture. One or more pelvic fractures were present in nine (75%) of the 12 patients (p < 0.001). Pubic symphysis diastasis, sacroiliac diastasis, and sacral, iliac, and pubic rami fractures were statistically associated with bladder rupture. Isolated acetabular fractures did not correlate with rupture. Eight (67%) of the 12 patients with bladder rupture revealed on CT cystography had gross hematuria (p < 0.001). No ruptures were seen in patients with <25 RBC/HPF (red blood cells per high-power field). All patients with rupture had pelvic fluid revealed on standard contrast-enhanced CT (p < 0.001). CONCLUSION: Gross hematuria, pelvic fluid, and specific pelvic fractures were highly correlated with bladder rupture; identification of these findings may help in selection of trauma patients for CT cystography.

Adolescent↗
PubMed2000

Focal posttransplantation lymphoproliferative disorder at the renal allograft hilum.

OBJECTIVE: This report describes the imaging characteristics of focal posttransplantation lymphoproliferative disorder. CONCLUSION: Posttransplantation lymphoproliferative disorder may be limited to the allograft. A focal complex mass in the renal allograft hilum surrounding the main renal blood vessels is a common finding and can be visualized with sonography. MR imaging can help increase diagnostic confidence.

Adult↗
PubMed1998

Hysterosalpingography with videofluoroscopy: effect on radiologic practice in an academic medical center.

RATIONALE AND OBJECTIVES: The authors attempted to determine whether videotaping the fluoroscopic portion of hysterosalpingography would result in changed diagnoses or an increase in diagnostic confidence. MATERIALS AND METHODS: Ninety-nine consecutive outpatients underwent routine hysterosalpingography. The fluoroscopic portion of the examination was captured on videotape. Two consecutive interpretations of each hysterosalpingogram were made by attending radiologists. First, spot radiographs were interpreted alone. Second, these images were viewed along with videofluoroscopy. Concordance of and confidence in findings for the two interpretations were assessed with the two-tailed Fisher exact test. RESULTS: Interpretations of spot radiographs alone and with videofluoroscopy were in agreement in 92 of 99 uterine examinations and 164 of 198 tubal examinations. For uterine examinations classified as normal, interpretations of spot radiographs and videofluoroscopy were in agreement in 56 of 57 cases; there was no change in confidence with review of videofluoroscopic images. For uterine examinations interpreted as abnormal, agreement was noted in 36 of 42 cases (P = .04), and confidence increased with videofluoroscopy in 10 of 42 cases (P = .00001). With normal tubal findings, interpretations agreed in 94 of 118 cases, and confidence increased in 56 of 118 cases (P = .002). With abnormal tubal findings, interpretations agreed in 70 of 80 cases, and confidence increased in 20 of 80 cases (P = .002). When findings with and without videofluoroscopy were discordant, confidence was always higher after review of video-fluoroscopic images. CONCLUSION: Review of videofluoroscopic images obtained during hysterosalpingography increases the accuracy and confidence of diagnoses compared with review of spot radiographs alone.

Academic Medical Centers↗
PubMed1998

Myelolipoma: CT and pathologic features.

PURPOSE: To correlate clinical and pathologic patterns of myelolipoma with the computed tomographic (CT) appearance. MATERIALS AND METHODS: All cases of myelolipoma accessioned by the Armed Forces Institute of Pathology from 1981 through 1997 were reviewed. CT images were scored for the location and size of each myelolipoma and the presence of calcification, hemorrhage, fat, and pseudocapsule. Pathologic findings for the pattern of fat and bone marrow elements were correlated with CT findings. RESULTS: In 74 patients, 86 myelolipomas were found, of which 72 were in an adrenal gland (eight were bilateral), and 14 extra-adrenal masses were found in 10 patients. Four clinicopathologic patterns emerged: (a) isolated adrenal myelolipoma in 37 patients (fat evident at CT, no other disorders present); (b) myelolipoma with hemorrhage in nine patients (imaging features similar to those of isolated adrenal myelolipomas but larger [mean diameter, 14.2 vs 9.9 cm; P = .01]; (c) extra-adrenal myelolipoma in 10 patients (imaging findings similar to those of adrenal myelolipomas, found most often in the retroperitoneum); and (d) myelolipomatous foci within other adrenal pathologic conditions in 18 patients (smaller, lower fat content, more heavily calcified). CONCLUSION: Myelolipomas are adrenal or extra-adrenal masses, with hemorrhage more common in larger lesions (diameter, > 10 cm). The CT appearance of myelolipomatous foci, which can be found within other pathologic adrenal conditions, is different from that of isolated adrenal myelolipomas.

Adipose Tissue↗
PubMed1998

Gastric stromal sarcomas: correlation of MR imaging and histopathologic findings in nine patients.

PURPOSE: To define the appearance of gastric stromal sarcomas at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Nine patients with gastric stromal sarcoma underwent MR imaging with the following sequences: nonenhanced and gadolinium-enhanced breath-hold, T1-weighted, spoiled gradient-recalled echo (n = 9); fat-suppressed, T2-weighted, fast spin echo (n = 9); and breathing-independent, half-Fourier rapid acquisition with relaxation enhancement (n = 6). Lesion morphology, signal intensity features, and relationships to the gastric wall and surrounding organs were retrospectively evaluated. The diagnosis of gastric stromal sarcoma was histologically proved in all patients. RESULTS: The nine tumors were solitary, multilobulated, shaped irregularly, predominantly exophytic, and large (diameter range, 7-28 cm [mean, 15.8 cm]). The epicenters of all lesions were extrinsic to the stomach, and all lesions arose from the gastric cardia or body. Regions of necrosis and hemorrhage were detected in all cases. Marginal definition on MR images corresponded to histologic grade: High-grade neoplasms possessed ill-defined margins, and low-grade neoplasms demonstrated more well-defined margins. Relationships to surrounding organs depicted at MR imaging corresponded well with histopathologic findings. CONCLUSION: Gastric stromal sarcomas demonstrate characteristic MR imaging features, which correspond well with histopathologic findings. The direct multiplanar capability of MR imaging facilitates delineation of relationships of the tumors to the stomach and surrounding organs.

Adult↗
PubMed1998

Deeper stratum.

Explore the source record for details and available documents.

Humans↗
PubMed1997

Computed model of gadolinium enhanced MRI of breast disease.

OBJECTIVE: Investigation has shown that the most useful MRI finding for the detection of breast cancer is enhancement following in travenous contrast. However, many widely different imaging protocols have been used. The purpose of this study is to explicate factors that affect the signal intensity of breast lesions after intravenous gadolinium. METHODS AND MATERIALS: A computer model was developed using equations based on published data. The effect of gadolinium on breast tissues was calculated using the model with appropriate values for baseline tissue relaxation times, relaxivity of gadolinium at the given field strength and concentration of gadolinium based on published data, for the TR, TE, flip angle and field strength of several published sequences used for enhanced breast MRI. RESULTS: The computer model allows comparison of the performance of different sequences, which can be displayed graphically. These vary in their performance, largely dependent on T1 weighting. Enhancement is also affected by the baseline of the T1 of the lesion and sensitivity of the sequence to gadolinium. Malignant lesions demonstrate greater observed enhancement than predicted when assuming symmetric distribution of contrast, indicating there is greater accumulation of gadolinium, accounting for the differential enhancement between benign and malignant lesions. CONCLUSIONS: MRI sequences vary greatly in their demonstration of enhancement after intravenous gadolinium contrast. Numerical diagnostic criteria such as % signal intensity change must be interpreted with care when using a different sequence than that on which the criterion was developed. There is preferentially greater accumulation of contrast in malignant lesions, whether due to angiogenesis or altered permeability.

Algorithms↗
PubMed1997

Pancreatic fluid collections prior to intervention: evaluation with MR imaging compared with CT and US.

PURPOSE: To evaluate the ability of magnetic resonance (MR) imaging to depict solid debris within pancreatic collections prior to intervention and to help assess drainability, as well as to compare MR findings with those obtained at computed tomography (CT) and ultrasound (US). MATERIALS AND METHODS: Nineteen collections in 18 patients were evaluated with MR imaging, CT, and US prior to drainage. Prospective, blinded interpretations of imaging studies by three independent readers (each interpreted all the images obtained with only one modality) evaluated collection characteristics (debris, consistency, septation, wall thickness, and irregularity) and predicted drainability. Findings were compared with clinical diagnosis and clinical outcome of drainage. RESULTS: MR imaging and CT depicted all collections; US failed to depict two collections. In nine patients with subacute necrotic collections, solid debris was seen in eight (89%) at MR imaging, in two (22%) at CT, and in eight (89%) at US. In seven patients with pseudocysts, debris was seen in two (28%) at MR imaging and in none at CT, as well as in six (100%) of six at US. A collection was defined as "not drainable" on the basis of the depiction of solid necrotic debris more than 1 cm in diameter. With this definition, statistically significant differences between sensitivity and specificity values, respectively, were found for the prediction of actual drainability: MR imaging, 100% and 100%; CT, 25% and 100%; US, 88% and 54%. CONCLUSION: Predrainage MR imaging should be performed in patients with subacute pancreatic collections to avoid infectious complications from unrecognized necrotic debris that cannot be removed with use of standard pseudocyst drainage techniques.

Abscess↗
PubMed1996

Adrenal myelolipoma.

In 1905, Gierke [1] first described the occurrence of a tumor in the adrenal composed of mature fat and mixed myeloid and erythroid cells, subsequently termed "formations myelolipomatoses" by Oberling [2] in 1929.

Adrenal Gland Neoplasms↗
PubMed1993

MR imaging of the hands in early rheumatoid arthritis: preliminary results.

Several magnetic resonance (MR) imaging pulse sequences (unenhanced T1 weighted spin echo, with and without fat suppression; unenhanced T2 weighted with fat suppression; and spoiled gradient-recalled acquisition in the steady state [GRASS], with fat suppression, before and after gadolinium enhancement) were analyzed in 30 patients with early rheumatoid arthritis to determine which sequences were best for imaging various aspects of the disease as manifested in the hands and wrists. A single hand was imaged in all patients. Inflammation and erosions were best seen on spoiled GRASS images with fat suppression and gadolinium enhancement, with the latter also being well seen on T1-weighted images. Articular cartilage was best seen on unenhanced spoiled GRASS or T1-weighted images with fat suppression. For the latter application, increased resolution is needed before the results will be meaningful. MR imaging has potential as an objective method for evaluating rheumatoid arthritis. However, change in MR imaging findings in a single hand must be carefully monitored and compared with the overall disease course for a long period in a large number of patients to establish the clinical value of MR imaging.

Adolescent↗
PubMed1993

MR imaging of anatomy and tears of wrist ligaments.

Numerous intrinsic and extrinsic wrist ligaments are visible at magnetic resonance (MR) imaging. Because the previously published descriptions of these ligaments were often conflicting, the authors derived a classification system based on a functional perspective and their experience with MR imaging, arthroscopy, and surgical dissection. This system was used to evaluate MR images of 23 cadaveric wrists for the presence and integrity of 16 wrist ligaments. MR images were prospectively analyzed by two observers, and all findings were correlated with the results of arthroscopy. The best detection rates and diagnostic confidence rates were achieved for the triangular fibrocartilage (100% and 100%, respectively) and the scapholunate ligament (91% and 87%, respectively). Other ligaments were less well seen, partly because of their size and course. Eighty-two percent of the triangular fibrocartilage tears, 50% of the scapholunate tears, and 40% of the lunotriquetral tears seen at arthroscopy were detectable on MR images. Identification of these three types of tears on MR images is important because they are functionally significant and because there are accepted methods of treating them in orthopedic practice.

Aged↗