Evaluation of a new DXA fan-beam instrument for measuring body composition.
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Absorptiometry, Photon↗
Biomedical subjects
J A Hanson
Publications and source records attributed to J A Hanson.
Induction of proinflammatory cytokines from human respiratory epithelial cells after stimulation by nontypeable Haemophilus influenzae.
Nontypeable Haemophilus influenzae (NTHi) causes repeated respiratory infections in patients with chronic lung diseases. These infections are characterized by a brisk inflammatory response which results in the accumulation of polymorphonucleated cells in the lungs and is dependent on the expression and secretion of proinflammatory cytokines. We hypothesize that multiple NTHi molecules, including lipooligosaccharide (LOS), mediate cellular interactions with respiratory epithelial cells, leading to the production of proinflammatory cytokines. To address this hypothesis, we exposed 9HTEo- human tracheal epithelial cells to NTHi and compared the resulting profiles of cytokine gene expression and secretion using multiprobe RNase protection assays and enzyme-linked immunosorbent assays (ELISA), respectively. Dose-response experiments demonstrated a maximum stimulation of most cytokines tested, using a ratio of 100 NTHi bacterial cells to 1 9HTEo- tracheal epithelial cell. Compared with purified LOS, NTHi bacterial cells stimulated 3.6- and 4.5-fold increases in epithelial cell expression of interleukin-8 (IL-8) and IL-6 genes, respectively. Similar results were seen with epithelial cell macrophage chemotactic protein 1, IL-1alpha, IL-1beta, and tumor necrosis factor alpha expression. Polymyxin B completely inhibited LOS stimulation but only partially reduced NTHi whole cell stimulation. Taken together, these results suggest that multiple bacterial molecules including LOS contribute to the NTHi stimulation of respiratory epithelial cell cytokine production. Moreover, no correlation was seen between NTHi adherence to epithelial cells mediated by hemagglutinating pili, Hia, HMW1, HMW2, and Hap and epithelial cytokine secretion. These data suggest that bacterial molecules beyond previously described NTHi cell surface adhesins and LOS play a role in the induction of proinflammatory cytokines from respiratory epithelial cells.
Bacterial Adhesion↗
Radiologic spectrum of craniocervical distraction injuries.
Injuries to the atlanto-occipital region, which range from complete atlanto-occipital or atlantoaxial dislocation to nondisplaced occipital condyle avulsion fractures, are usually of critical clinical importance. At initial cross-table lateral radiography, measurement of the basion-dens and basion-posterior axial line intervals and comparison with normal measurements may help detect injury. Computed tomography (CT) with sagittal and coronal reformatted images permits optimal detection and evaluation of fracture and luxation. CT findings that may suggest atlanto-occipital injury include joint incongruity, focal hematomas, vertebral artery injury, capsular swelling, and, rarely, fractures through cranial nerve canals. Magnetic resonance (MR) imaging of the cervical spine with fat-suppressed gradient-echo T2-weighted or short-inversion-time inversion recovery sequences can demonstrate increased signal intensity in the atlantoaxial and atlanto-occipital joints, craniocervical ligaments, prevertebral soft tissues, and spinal cord. Axial gradient-echo MR images may be particularly useful in assessing the integrity of the transverse atlantal ligament. All imaging studies should be conducted with special attention to bone integrity and the possibility of soft-tissue injury. Atlanto-occipital injuries are now recognized as potentially survivable, although commonly with substantial morbidity. Swift diagnosis by the trauma radiologist is crucial for ensuring prompt, effective treatment and preventing delayed neurologic deficits in patients who survive such injuries.
Atlanto-Axial Joint↗
CT assessment of tumour response to treatment: comparison of linear, cross-sectional and volumetric measures of tumour size.
Changes in cross-sectional area are currently used to assess tumour response to treatment. The aims of this study were to validate a helical CT technique for volume determination using a series of phantoms and to compare tumour responses indicated by one-, two- and three-dimensional measures of tumour size change in patients treated for germ cell cancer or lymphoma. All studies were performed on an IGE HiSpeed Advantage helical CT scanner with an Advantage Windows workstation. Phantom volumes were calculated using volume reconstruction software and compared with reference volumes determined by water displacement. 20 lymph node masses were studied on serial CT scans in 16 patients treated with chemotherapy for germ cell cancer or lymphoma. For each lesion the maximum diameter, maximum cross-sectional area and volume were determined before and after treatment. Tumour response was assessed using the standard World Health Organisation criteria (i.e. changes in cross-sectional area) and the newly proposed unidimensional response evaluation criteria in solid tumour (RECIST). The CT volume measurement error was 1.0-5.1% for regularly shaped phantoms larger than 35 cm3. In the assessment of treatment response there was 90% agreement between one-dimensional (1D) and two-dimensional (2D) measurements and 100% agreement between 2D and three-dimensional (3D) measurements. CT volume measurements are accurate and reproducible, particularly for larger structures. Assessment of tumour response using 1D, 2D and 3D measures had limited influence on the classification of treatment response. However, the impact of CT assessment of tumour response using 1D, 2D and 3D measurements on clinical decisions and patient outcome remains to be determined.
Adult↗
Bilateral measurement of femoral bone mineral density.
Both femora were measured on 61 normal adults using dual X-ray absorptiometry (DXA). In a subset of 31 subjects, each femur was scanned once using the conventional leg-positioning device supplied with the densitometer, and once using a new positioning device and software that allowed both legs to be measured simultaneously. In another subgroup (n = 30), subjects were measured three times using the new dual-femur approach to better assess precision error. The data were analyzed for differences owing to the different positioning devices and for differences between right and left sides. The correlation between results with the old and new positioners was high (r > 0.99, standard error of the estimate [SEE] = 0.01-0.02 g/cm(2)). There was no significant difference in the average bone mineral density (BMD) values between the old and new positioner. The precision errors for each femur alone with the dual-femur approach were similar to those reported for the single-femur scans (1 to 2%), but the precision errors for the combined femora were reduced by 30% as expected. The correlation between right and left sides was high (r = 0.94-0.96), and the SEE in predicting one side from the other was moderate for total, trochanteric, and femoral neck BMD (0.05, 0. 05, and 0.06 g/cm(2), respectively). These SEE equate to about 0.5 standard deviation in terms of T-score. Differences in many individual cases between the right and left sides were significantly greater than the precision error. The new dual-femur software and leg positioner allows rapid measurement and analysis of both femora, thereby eliminating the uncertainty between sides.
Absorptiometry, Photon↗
Predisposition for spinal fracture in ankylosing spondylitis.
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Adult↗
Cervical spine injury: a clinical decision rule to identify high-risk patients for helical CT screening.
OBJECTIVE: We aimed to validate the routine use of a clinical decision rule to direct diagnostic imaging of adult blunt trauma patients at high risk for cervical spine injury. MATERIALS AND METHODS: We previously developed and have since routinely used a prediction rule based on six clinical parameters to identify patients at greater than 5% risk of cervical spine injury to undergo screening helical CT of the cervical spine. During a 6-month period, 4285 screening imaging studies of the cervical spine were performed in adult blunt trauma patients. Six hundred one patients (398 males, 203 females; age range, 16-100 years; median age, 38 years) underwent helical CT, and the remainder underwent 3684 conventional radiographic examinations. Clinical and report data were extracted from the radiology department database, medical records, and the hospital trauma registry. Abnormal findings were independently confirmed by additional imaging studies, autopsy results, or clinical outcome. RESULTS: The true-positive cervical spine injury rates in helical CT- and conventional radiography-screened patients who presented directly to our trauma center were 40 (8.7%) of 462 and seven (0.2%) of 3684, respectively. The cervical spine injury rate in patients who were transferred from outside institutions to our trauma center and who underwent helical CT was 37 (26.6%) of 139. This figure included 20 patients already known to have cervical spine fracture. CONCLUSION: The clinical decision rule can distinguish patients at high and low risk of cervical spine injury, thus supporting its validity.
Adolescent↗
Dialysis modality and the risk of allograft thrombosis in adult renal transplant recipients.
BACKGROUND: Renal vascular thrombosis (RVT) is a rare but catastrophic complication of renal transplantation. Although a plethora of risk factors has been identified, a large proportion of cases of RVT is unexplained. Uremic coagulopathy and dialysis modality may predispose to RVT. We investigated the impact of the pretransplant dialysis modality on the risk of RVT in adult renal transplant recipients. METHODS: Renal transplant recipients (age 18 years or more) who were enrolled in the national registry between 1990 and 1996 (N = 84,513) were evaluated for RVT occurring within 30 days of transplantation. Each case was matched with two controls from the same transplant center and with the year of transplantation. The association between RVT and 18 factors was studied with multivariate conditional logistic regression. RESULTS: Forty-nine percent of all cases of RVT (365 out of 743) occurred in repeat transplant recipients with an adjusted odds ratio (OR) of 5.72 compared with first transplants (P < 0.001). There were a significantly higher odds of RVT in peritoneal dialysis (PD)-compared with hemodialysis (HD)-treated patients (OR = 1.87, P = 0.001). Change in dialysis modality was an independent predictor of RVT: switching from HD to PD (OR = 3.59, P < 0.001) and from PD to HD (OR = 1.62, P = 0.047). Compared with primary transplant recipients on HD (OR = 1.00), the highest odds of RVT were in repeat transplant recipients treated with PD (OR = 12.95, P < 0.001) and HD (OR = 4.50, P < 0.001). Other independent predictors of RVT were preemptive transplantation, relatively young and old donor age, diabetes mellitus and systemic lupus erythematosus as causes of end-stage renal disease, recipient gender, and lower panel reactive antibody levels (PRAs). CONCLUSIONS: The strongest risk factors for RVT were retransplantation and prior PD treatment. Prevention of RVT with perioperative anticoagulation should be studied in patients who have a constellation of the identified risk factors.
Adolescent↗
Analysis of right ventricular areas to assess the severity of ascites syndrome in broiler chickens.
Ascites syndrome in broiler chickens is defined as a condition associated with pulmonary hypertension leading to right heart failure, increased central venous pressure, passive congestion of the liver, and accumulations of serous fluids in body cavities. The syndrome is currently seen in fast-growing broiler chickens associated with an increase in the weight, volume, and area of the right ventricle of the heart. The ratio of the right ventricle weight to the total heart mass has been used to assess the consequences of increased blood pressure. The right ventricle area (RVA) can be quantified using image analysis technology. Hearts were removed from 719 male broilers at slaughter (42 d). All birds were visually scored for the incidence of ascites. A score of 0 or 1 represented slight hydropericardium, slight right heart hypertrophy, and slight edema. A score of 4 was assigned to birds with marked accumulation of ascitic fluid in one or more ceolomic cavities, pronounced dilation of the right heart, and prominent liver lesions. A cross-sectional image of each heart slice (a 4-mm-thick slice of the ventricles) was digitally recorded. Using image analysis software, the RVA, left ventricular area (LVA), and total heart area (HA) were determined. Because a slice of the heart was used in image analysis, the importance of maintaining the original shape was determined. Twenty hearts in five ranges of RVA size were scanned in four different positions, which have differing heart slice orientations and differing RVA shapes, for a comparison of positioning technique (placement) relating to the RVA. The shape of the heart slice for image analysis was observed not to be critical for the small RVA. For heart slices with large RVA values, it was found to be critical to analyze the heart slice in a standardized placement.
Animals↗
Growth performance, carcass characteristics, and the incidence of ascites in broilers in response to feed restriction and litter oiling.
The effect of feed restriction and the application of canola oil to broiler straw litter to contain respirable dust on growth performance, carcass traits, and the incidence of ascites was evaluated with 800 male broilers studied in two 6-wk periods. Two pens of birds were feed restricted. Two pens of birds received feed ad libitum for the 6-wk trial. One restricted and one ad libitum pen received biweekly addition of canola oil to the litter. At 6 wk of age, 30 birds from each pen were killed for determination of breast muscle, fat pad, and heart weights. All birds were scored for the incidence of ascites at processing. A cross sectional image of each heart was digitally recorded and, using image analysis, the right ventricular area (RVA), left ventricular area (LVA), and total heart area (HA) were determined. The right ventricular wall was removed and its weight was expressed as a percentage of total heart weight (PRVW). The 40-d BW was significantly greater in the ad libitum birds (2.07 kg) than in the feed-restricted birds (1.86 kg). The right ventricular weight (RVW) (1.69 and 1.92 g) and the RVA (0.35 and 0.40 cm2) were also significantly different between the two feeding treatments. The ascites score was significantly correlated to the RVW (r = 0.50) and RVA (r = 0.52). The RVA was also correlated to the RVW (r = 0.63). Oiling the litter did not result in differences in carcass characteristics. Litter oiling significantly reduced the RVA of the ad libitum birds (0.36 cm2) compared to the ad libitum birds that did not have oiled litter (0.44 cm2). Feed restriction reduced the incidence of ascites, but also reduced gain. Litter oiling in the feed-restricted groups reduced the RVA, but did not reduce mortality.
Adipose Tissue↗
The R-type pyocin of Pseudomonas aeruginosa C is a bacteriophage tail-like particle that contains single-stranded DNA.
Pseudomonas aeruginosa R-type pyocin particles have been described as bacteriocins that resemble bacteriophage tail-like structures. Because of their unusual structure, we reexamined whether they contained nucleic acids. Our data indicated that pyocin particles isolated from P. aeruginosa C (pyocin C) contain DNA. Probes generated from this DNA by the random-primer extension method hybridized to distinct bands in restriction endonuclease-digested P. aeruginosa C genomic DNA. These probes also hybridized to genomic DNA from 6 of 18 P. aeruginosa strains that produced R-type pyocins. Asymmetric PCR, complementary oligonucleotide hybridization, and electron microscopy indicated that pyocin C particles contained closed circular single-stranded DNA, approximately 4.0 kb in length. Examination of total intracellular DNA from mitomycin C-induced cultures revealed the presence of two extrachromosomal DNA molecules, a double-stranded molecule and a single-stranded molecule, which hybridized to pyocin DNA. Sequence analysis of 7,480 nucleotides of P. aeruginosa C chromosomal DNA containing the pyocin DNA indicated the presence of pyocin open reading frames with similarities to open reading frames from filamentous phages and cryptic phage elements. We did not observe any similarities to known phage structural proteins or previously characterized pseudomonal prt genes expressing R-type pyocin structural proteins. These studies demonstrate that pyocin particles from P. aeruginosa C are defective phages that contain a novel closed circular single-stranded DNA and that this DNA was derived from the chromosome of P. aeruginosa C.
Amino Acid Sequence↗
Prescription of twice-weekly hemodialysis in the USA.
BACKGROUND/AIMS: The purpose of this study was to investigate the frequency and characteristics of two hemodialysis sessions/week, to identify factors which influence or predict this prescription, and to examine the outcomes of patients receiving hemodialysis two times/week as compared to the more common treatment of three times/week. METHODS: Data from a national sample of 15,067 adult hemodialysis patients were utilized to compare twice-weekly with thrice-weekly therapy by logistic regression. RESULTS: Patients treated less than one year were more likely to be treated twice-weekly (6.1%) than patients on dialysis for one year or more (2.7%) (AOR = 1.49, p = 0.002). Treatment schedules also varied significantly by geographic region. Factors predictive of twice-weekly hemodialysis (p < 0.05) were older age, Caucasian race, female gender, higher serum albumin, lower serum creatinine levels, and lower body mass index. A higher estimated renal function at the start of ESRD was also predictive of a twice-weekly schedule among incident patients (AOR = 1.05, p = 0.05). In addition, Cox-adjusted survival analysis indicated a lower mortality risk (RR = 0.76, p = 0. 02) for twice-weekly hemodialysis compared to thrice-weekly among prevalent patients. For incident patients, however, the results were not significant when adjusted for GFR at ESRD onset (RR = 0.85, p = 0.31). CONCLUSION: Geographic differences in prescribed treatment remained unexplained by measured characteristics. The survival advantage associated with twice-weekly hemodialysis is likely to be related to patient selection and greater residual renal function.
Adult↗
Computed tomography appearance of the thymus and anterior mediastinum in active Cushing's syndrome.
Computed tomography (CT) evaluation of the thymus and anterior mediastinum is an important aspect of the investigation of patients with ACTH-dependent Cushing's syndrome in order to exclude an ACTH-secreting carcinoid tumor. We have reviewed the CT imaging of the thymus and anterior mediastinum in a series of 85 patients (55 females; median age 41, range 7-77 yr) with active Cushing's syndrome as there are few data on the range of appearances in hypercortisolemic states. One patient had a thymic carcinoid tumor (24 x 18 mm). Of the others, 28/84 (33%) patients showed thymic remnant tissue, consisting of either nodule(s) at least 5 mm diameter (n = 21, mean diameters 12.5 +/- 5 x 9.6 +/- 4 mm), or triangular bilobed glands (n = 7, mean thickness of the body, right and left limbs 25 +/- 7, 14 +/- 3, and 12 +/- 5 mm). Thymic involution appeared in 56/84 (67%) patients, ranging from small nodule(s) of less than 5mm diameter to linear soft tissue strands and complete fatty replacement. Patients with thymic remnant tissue were younger than those with thymic involution (P < 0.05). The thymic carcinoid tumor could be distinguished from remnant tissue on the basis of age and size. The presence of anterior mediastinal nodule(s) in hypercortisolemia need not imply the presence of a thymic carcinoid tumor, although in older patients this should arouse suspicion.
ACTH Syndrome, Ectopic↗
CT appearance of the adrenal glands in adrenocorticotrophic hormone-dependent Cushing's syndrome.
OBJECTIVE: The purpose of this study was to describe the size and appearance of the adrenal glands on CT in patients with adrenocorticotrophic hormone (ACTH)-dependent Cushing's syndrome and to correlate gland dimensions with circulating cortisol and ACTH levels. MATERIALS AND METHODS: We retrospectively analyzed clinical, biochemical, and imaging data for 53 patients referred for CT of the adrenals as part of an investigation for ACTH-dependent Cushing's syndrome at our institution between 1988 and 1997. Two observers, who were unaware of the endocrine data, measured the body and limb widths of the adrenal glands using an electronic cursor. RESULTS: Of the 53 patients, 37 (70%) were shown to have enlarged adrenal glands on CT. The mean width of the adrenal limbs positively correlated with the circulating cortisol and ACTH levels. The adrenals were larger in patients with ectopic ACTH syndrome than in patients with Cushing's disease (p < .02). Ten patients (19%) had nodules that were 10 mm or greater in diameter. CONCLUSION: The adrenal glands were often enlarged in patients with ACTH-dependent Cushing's syndrome, and the enlargement could be quantified on CT. However, having normalsized adrenals (observed in 30% the patients in our study) did not preclude such a diagnosis. We found that adrenal limb width positively correlates with ACTH and cortisol levels.
ACTH Syndrome, Ectopic↗
Maisonneuve fracture of the fibula: implications for imaging ankle injury.
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Adult↗
What is your diagnosis? Foreign body obstruction of the duodenum with reflux of barium sulfate into the gallbladder and intrahepatic bile ducts.
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Animals↗
Characterization of highly radiosensitive cell lines from a human ovarian small-cell cancer.
Cells were obtained at paracentesis from a patient with a rapidly growing ovarian tumor. A monolayer cell line (V7S), a xenograft tumor line (V7), and subsequently a xenograft-derived monolayer cell line (V7M) were established. Histological and immunohistochemical studies of the original tumor, xenograft, and cell lines provided a diagnosis of small-cell carcinoma of the ovary-which is consistent with the clinical course of the patient. V7S and V7M had a predominantly hypodiploid karyotype with a small tetraploid population. The V7M, which has been in long-term culture, also showed a nonrandom translocation involving chromosomes 1 and 14 and monosomy of X. Radiobiologically, V7S, V7, and V7M showed marked radiosensitivity with surviving fractions at 2 Gy, measured by clonogenic assay, of between 0.022 and 0.147. Split-dose experiments provided evidence that this radiosensitivity was not due to an inability in cellular repair. In vivo data from the xenograft (V7) revealed a highly radiosensitive tumor, corroborating the in vitro studies.
Carcinoma, Small Cell↗
Staging intrathoracic non-small-cell lung cancer.
This article outlines the ability of imaging techniques to stage intrathoracic non-small-cell lung cancer, particularly the extent of primary tumour (T stage), and the presence of nodal metastases (N stage). The detection of hilar and mediastinal lymph-node metastases by CT is covered initially, followed by an appraisal of MRI and radionuclide imaging techniques. Finally, the evaluation of mediastinal and chest-wall invasion by CT and MRI is described, and note is made of developing applications of ultrasound and endosonography. Computed tomography remains the standard technique, but its limitations are discussed, as is the value of other complementary imaging techniques.
Carcinoma, Non-Small-Cell Lung↗