Search PubMed⌕ Search

Biomedical subjects

Bernard F King

Publications and source records attributed to Bernard F King.

At least 19 recordsLinked to original sources

Volume progression in polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive enlargement of cyst-filled kidneys. METHODS: In a three-year study, we measured the rates of change in total kidney volume, total cyst volume, and iothalamate clearance in patients with ADPKD. Of a total of 241 patients, in 232 patients without azotemia who were 15 to 46 years old at baseline we used magnetic-resonance imaging to correlate the total kidney volume and total cyst volume with iothalamate clearance. Statistical methods included analysis of variance, Pearson correlation, and multivariate regression analysis. RESULTS: Total kidney volume and total cyst volume increased exponentially, a result consistent with an expansion process dependent on growth. The mean (+/-SD) total kidney volume was 1060+/-642 ml at baseline and increased by a mean of 204+/-246 ml (5.27+/-3.92 percent per year, P<0.001) over a three-year period among 214 patients. Total cyst volume increased by 218+/-263 ml (P<0.001) during the same period among 210 patients. The baseline total kidney volume predicted the subsequent rate of increase in volume, independently of age. A baseline total kidney volume above 1500 ml in 51 patients was associated with a declining glomerular filtration rate (by 4.33+/-8.07 ml per minute per year, P<0.001). Total kidney volume increased more in 135 patients with PKD1 mutations (by 245+/-268 ml) than in 28 patients with PKD2 mutations (by 136+/-100 ml, P=0.03). CONCLUSIONS: Kidney enlargement resulting from the expansion of cysts in patients with ADPKD is continuous and quantifiable and is associated with the decline of renal function. Higher rates of kidney enlargement are associated with a more rapid decrease in renal function.

Adult↗

Clinical and molecular characterization defines a broadened spectrum of autosomal recessive polycystic kidney disease (ARPKD).

The autosomal recessive form of polycystic kidney disease (ARPKD) is generally considered an infantile disorder with the typical presentation of greatly enlarged echogenic kidneys detected in utero or within the neonatal period, often resulting in neonatal demise. However, there is an increasing realization that survivors often thrive into adulthood with complications of the ductal plate malformation, manifesting as congenital hepatic fibrosis and Caroli disease, becoming prominent. Previous natural history studies have concentrated almost exclusively on the infantile presenting group. However, developments in understanding the genetic basis of ARPKD, through identification of the disease gene, PKHD1, have allowed exploration of the etiology in patients with ARPKD-like disease or congenital hepatic fibrosis presenting later in childhood or as adults. In the current study we retrospectively reviewed the clinical records, and where possible performed PKHD1 mutation screening, in patients diagnosed with ARPKD or congenital hepatic fibrosis at the Mayo Clinic, Rochester, MN, from 1961 to 2004. Of a total of 133 cases reviewed, 65 were considered to meet the diagnostic criteria with an average duration of follow-up of 8.6 +/- 6.4 years. Fifty-five cases had ARPKD and 10 had isolated congenital hepatic fibrosis with no or minimal renal involvement. The patients were analyzed as 3 groups categorized by the age at diagnosis; <1 years (n = 22), 1-20 years (n = 23), and >20 years (n = 20). The presenting feature in the neonates was typically associated with renal enlargement, but in the older groups, more often involved manifestations of liver disease, including hepatosplenomegaly, hypersplenism, variceal bleeding, and cholangitis. During follow-up, 22 patients had renal insufficiency and 8 developed end-stage renal disease (ESRD), most from the neonatal group. Liver disease was evident on follow-up in all diagnostic groups but particularly prevalent in those diagnosed later in life. A total of 12 patients died, 6 in the neonatal period, but 86% of patients were alive at 40 years of age. The likelihood of being alive without ESRD differed significantly between the diagnostic groups with 36%, 80%, and 88% survival in the 3 diagnostic groups, respectively, 20 years after the diagnosis. Considerable evidence of intrafamilial phenotype variability was observed. Mutation analysis was performed in 31 families and at least 1 mutation was detected in 25 (81%), with 76% of mutant alleles detected in those cases. Consistent with the relatively mild disease manifestations in this population, the majority of changes were missense (79%) and no case had 2 truncating changes. Mutations were detected in all diagnostic groups, indicating that congenital hepatic fibrosis with minimal kidney involvement can result from PKHD1 mutation. The finding of 6 cases with no detected mutations may represent missed mutations or possible evidence of genetic heterogeneity. The current study indicates a broadened spectrum for the ARPKD phenotype and that later presenting cases with predominant liver disease should be considered part of ARPKD.

Adolescent↗

Sonographic assessment of the severity and progression of autosomal dominant polycystic kidney disease: the Consortium of Renal Imaging Studies in Polycystic Kidney Disease (CRISP).

BACKGROUND: The accuracy and precision of ultrasonography (US) in assessing the severity of autosomal dominant polycystic kidney disease (ADPKD) is unknown. METHODS: US and magnetic resonance imaging (MRI) were performed at baseline and 1 year on 230 subjects with ADPKD. Ellipsoid volume was calculated from US length, width, and depth, and sequential transverse images were used to measure total and cystic volume directly. These were compared with MRI measurements of kidney volume and cystic volume. RESULTS: Variability between different sonographers ranged from 18% to 42%. Correlations between US and MRI volume were 0.88 and 0.89. The SD of the discrepancy from MRI ranged from 21% to 33% and was unrelated to kidney size or body mass. Kidney length was the most reproducible measurement, and its correlation with MRI volume was 0.84. All patients with an US volume less than 700 cm3 had an MRI volume less than 1,000 cm3, and all patients with an US volume greater than 1,700 cm3 had an MRI volume greater than 1,000 cm3. Increases in volume after 1 year were 12% +/- 36% for the ellipsoid method, 6% +/- 29% for the direct method, and 4.2% +/- 7.2% for MRI. Correlation between US and MRI measurement of fractional cyst volume was 0.80. CONCLUSION: Sonographic measurement of kidney volume in patients with ADPKD is inaccurate and lacks the precision necessary to measure short-term disease progression. However, sonography can provide an estimate of kidney volume that reflects severity and prognosis in individual patients.

Adolescent↗

Three-dimensional CT virtual endoscopy in the detection of simulated tumors in a novel phantom bladder and ureter model.

BACKGROUND AND PURPOSE: Cystoscopy and ureteroscopy have limitations in the evaluation for urothelial tumors, and both are invasive. We studied the utility of three-dimensional (3D) CT virtual endoscopy in phantom models. MATERIALS AND METHODS: A phantom pelvis was constructed of Plexiglas, porcine pelvic bones, and processed animal fat and scanned at various table speeds in a four detector-row CT machine for ability to detect "tumors" of Solidwater plastic polymer. Images were reconstructed at slice thicknesses of 2.5 to 5.0 mm and reconstructed in 3D for evaluation by two radiologists with no knowledge of the scanning parameters or tumor location. Similar studies were performed with a ureter model. RESULTS: With 5-mm slices, the sensitivity for bladder tumors ranged from 67% for 2-mm tumors to 100% for 4-mm tumors, with 12 false-positive findings. The overall sensitivity was 86% with 3.75-mm slices with one false positive, and with 2.5-mm slices, the sensitivity was 93%, again with one false positive. For the ureteral tumors, the overall sensitivities and numbers of false positives were 88.9% and eight with 5.0-mm collimation, 88.9% and four with 3.75-mm collimation, and 100% and three with 2.5-mm collimation. The effective radiation dose for all studies was equivalent to that of a standard abdomen/pelvis scan. CONCLUSIONS: Although virtual endoscopy traditionally has had difficulty detecting tumors <5 mm, the multidetector-row CT protocols used in this study could detect most lesions smaller than this. The scan also depicts the other tissues of the pelvis, which is valuable for staging. The 3D images were produced using data from the CT urogram parameters standard at our institution.

Animals↗

Prostate volume measurement by transrectal ultrasound and computed tomography before and after permanent prostate brachytherapy.

PURPOSE: To quantify prostate volume (pvol) changes with transrectal ultrasound (TRUS) immediately after permanent prostate brachytherapy (PPB) and to correlate these changes with postimplant computed tomography (CT) volumetrics. To provide data relevant to evaluating the potential of TRUS-based image fusion for intraoperative dosimetry. METHODS AND MATERIALS: Between July 2000 and January 2003, 177 patients underwent (125)I PPB monotherapy at our institution, and 165 patients provided research authorization. A total of 136 patients (82%) completed 4 imaging studies: planning TRUS, intraoperative pre- and postimplant TRUS, and CT. RESULTS: Mean planning TRUS pvol was 38.7 +/- 11.7 cc standard deviation (SD), 95% confidence interval (CI) (36.7, 40.7). Mean intraoperative TRUS pvol preimplant was 37.1 +/- 11.7 cc SD, 95% CI (35.1, 39.0), and postimplant was 44.5 +/- 15.1 cc SD, 95% CI (42.0, 47.1). The mean ratio of postimplant:preimplant intraoperative TRUS pvols was 1.2 +/- 0.2 SD, 95% CI (1.18, 1.24), and the difference in mean values was 7.5 cc (p < 0.0001). CT performed within 1 day revealed a mean pvol of 47.9 +/- 15.7 cc SD, 95% CI (45.2, 50.5). The mean volumetric ratio of CT to postimplant TRUS pvol was 1.13 +/- 0.36, 95% CI (1.07-1.19). CONCLUSIONS: Whereas mean preimplant step-section TRUS pvol measurements are similar, postimplant TRUS and CT measurements have greater variability that depend on initial pvol. CT-based pvol measurements determined a mean of 10.6 hours after implant were more likely to be identical to those of immediate postimplant TRUS in prostates >33 cc. These data are relevant for establishing accuracy in image-fusion based approaches being investigated for real-time intraoperative PPB dosimetry.

Analysis of Variance↗

Radioactive seed migration to the chest after transperineal interstitial prostate brachytherapy: extraprostatic seed placement correlates with migration.

PURPOSE: To examine the incidence of seed migration detected on chest X-ray and to identify the predictors associated with its occurrence. METHODS AND MATERIALS: Between May 1998 and April 2000, 102 patients underwent permanent prostate brachytherapy at our institution and 100 were eligible for the study. Chest X-rays obtained at follow-up were examined for the number and location of seeds. The patient and treatment variables potentially associated with the occurrence and number of seed migrations were analyzed. RESULTS: One or more seeds were identified on the chest X-rays of 55 (55%) of 100 patients. The mean number of intrathoracic seeds in patients with migration was 2.2 (range, 1-10), and the proportion of seeds that migrated to the thorax was 0.98%. The rate of extraprostatic seeds planned was 43.9%, and postimplant CT identified 37.9% in such a location. The number of seeds planned for extraprostatic placement and below the apex were statistically significant (alpha = 0.05) predictors in univariate logistic analysis. Multivariate analysis revealed the planned number of extraprostatic seeds as the only statistically significant predictor (p = 0.04). CONCLUSION: Extraprostatic placement of loose seeds is associated with an increased likelihood for, and frequency of, seed migration to the thorax. Nonetheless, the small proportion of implanted seeds that migrated (<or=1%) is highly unlikely to have significant dosimetric consequences.

Aged↗

Mutations in SEC63 cause autosomal dominant polycystic liver disease.

Mutations in PRKCSH, encoding the beta-subunit of glucosidase II, an N-linked glycan-processing enzyme in the endoplasmic reticulum (ER), cause autosomal dominant polycystic liver disease. We found that mutations in SEC63, encoding a component of the protein translocation machinery in the ER, also cause this disease. These findings are suggestive of a role for cotranslational protein-processing pathways in maintaining epithelial luminal structure and implicate noncilial ER proteins in human polycystic disease.

Chromosomes, Human, Pair 6↗

Evaluation of renal parenchymal disease in a rat model with magnetic resonance elastography.

Alterations in the mechanical properties or "hardness" of tissues allow physicians to detect disease by palpation. Recently, attempts have been made to quantitate and image these tissue properties with the use of magnetic resonance elastography (MRE). This technique has been validated in ex vivo specimens, including kidney, breast, and prostate. In this study, in vivo MRE imaging of rat renal cortex is demonstrated and validated with a disease model that will facilitate further studies. Normal rats and rats with nephrocalcinosis induced with either 2 or 4 weeks of ethylene glycol exposure were studied with MRE. Histology in the diseased rats documented the presence of nephrocalcinosis. MRE measurements and images of shear stiffness were highly reproducible in individual rats. The shear stiffness of the renal cortex in normal rats was 3.87 kPa (95% CI 2.84-4.90 kPa). The shear stiffness increased to 5.02 kPa (95% CI 3.34-6.70 kPa) after 2 weeks of exposure, and to 6.49 kPa (95% CI 4.84-8.14 kPa) after 4 weeks of exposure (P = 0.0302, alpha < 0.05). MRE is capable of detecting alterations in the tissue mechanical properties of kidneys in vivo. It is a promising noninvasive technique that might have pathologic and prognostic significance.

Animals↗

Imaging of urethral disease: a pictorial review.

Retrograde urethrography and voiding cystourethrography are the modalities of choice for imaging the urethra. Cross-sectional imaging modalities, including ultrasonography, magnetic resonance (MR) imaging, and computed tomography, are useful for evaluating periurethral structures. Retrograde urethrography is the primary imaging modality for evaluating traumatic injuries and inflammatory and stricture diseases of the male urethra. Sonourethrography plays an important role in the assessment of the thickness and length of bulbar urethral stricture. Although voiding cystourethrography is frequently used to evaluate urethral diverticula in women, MR imaging is highly sensitive in the demonstration of these entities. MR imaging is also accurate in the local staging of urethral tumors.

Adult↗

CT urography.

With the recent introduction of multi-detector row helical computed tomography (CT), the radiologic evaluation of patients with urologic disease has changed rapidly. Two major approaches to CT urography have been developed. The first approach combines axial CT with timed excretory urography (EU) performed by using conventional radiography, digital radiography, or CT scanned projection radiography (SPR). This approach produces traditional projection urograms, and the timed imaging technique is familiar to radiologists and clinicians. Additional excretory phase CT can be performed when the EU findings are positive or indeterminate. Improved CT SPR processing technology produces radiographlike images, thus eliminating patient transportation between the CT and urography suites or the necessity for a CT suite with a ceiling-mounted x-ray tube and a modified CT tabletop for performance of EU. The second approach to CT urography combines axial CT with thin-section excretory phase CT. The near-isotropic volume data set enables creation of high-resolution two- and three-dimensional reformatted images. However, the increased amount of radiation and the time required for data manipulation are concerns. Further studies evaluating large numbers of patients with various urothelial abnormalities will be necessary to determine the optimal CT urography technique for clinical practice.

Equipment Design↗

Technical aspects of daily online positioning of the prostate for three-dimensional conformal radiotherapy using an electronic portal imaging device.

PURPOSE: To develop a real-time electronic portal imaging device (EPID) procedure to identify intraprostatic gold markers and correct daily variations in target position during external beam radiotherapy for prostate cancer. METHODS AND MATERIALS: Pretherapy electronic portal images (EPIs) were acquired with a small portion of the therapeutic 18-MV dose from an orthogonal pair of treatment fields. The position of the intraprostatic gold markers on the EPIs was aligned with that on the simulation digitally reconstructed radiographs. If the initial three-dimensional target displacement (3DI) exceeded 5 mm or rotations exceeded 3 degrees, the beam was realigned before the remainder of the dose was delivered. Field-only EPIs were then acquired for all fields and offline analysis was performed to determine the final 3D target placement (3DF). RESULTS: Twenty patients completed protocol-specified treatment, and all markers were identified on 99.6% of the pretherapy EPIs. Overall, 53% of treatment fractions were realigned. The mean 3DI was 5.6 mm in all patients (range 3.7-9.3), and the mean 3DF was 2.8 mm (range 1.6-4.0), which was statistically significant (p < 0.001). Rotational corrections were made on 15% of treatments. Mean treatment duration was 1.4 min greater for protocol patients than for similar patients in whom localization was not performed. CONCLUSIONS: Frequent field misalignment occurs when external fiducial marks are used for patient alignment. Misalignments can be readily and rapidly identified and corrected with an EPID-based online correction procedure that integrates commercially available equipment and software.

Calibration↗

Mutations in PRKCSH cause isolated autosomal dominant polycystic liver disease.

Autosomal dominant polycystic liver disease (ADPLD) is a distinct clinical and genetic entity that can occur independently from autosomal dominant polycystic kidney disease (ADPKD). We previously studied two large kindreds and reported localization of a gene for ADPLD to an approximately 8-Mb region, flanked by markers D19S586/D19S583 and D19S593/D19S579, on chromosome 19p13.2-13.1. Expansion of these kindreds and identification of an additional family allowed us to define flanking markers CA267 and CA048 in an approximately 3-Mb region containing >70 candidate genes. We used a combination of denaturing high-performance liquid chromatography (DHPLC) heteroduplex analysis and direct sequencing to screen a panel of 15 unrelated affected individuals for mutations in genes from this interval. We found sequence variations in a known gene, PRKCSH, that were not observed in control individuals, that segregated with the disease haplotype, and that were predicted to be chain-terminating mutations. In contrast to PKD1, PKD2, and PKHD1, PRKCSH encodes a previously described human protein termed "protein kinase C substrate 80K-H" or "noncatalytic beta-subunit of glucosidase II." This protein is highly conserved, is expressed in all tissues tested, and contains a leader sequence, an LDLa domain, two EF-hand domains, and a conserved C-terminal HDEL sequence. Its function may be dependent on calcium binding, and its putative actions include the regulation of N-glycosylation of proteins and signal transduction via fibroblast growth-factor receptor. In light of the focal nature of liver cysts in ADPLD, the apparent loss-of-function mutations in PRKCSH, and the two-hit mechanism operational in dominant polycystic kidney disease, ADPLD may also occur by a two-hit mechanism.

Alternative Splicing↗

Prospective analysis of computerized tomography and needle biopsy with permanent sectioning to determine the nature of solid renal masses in adults.

PURPOSE: We prospectively determined the accuracy of computerized tomography (CT) and needle biopsy of solid renal masses. MATERIALS AND METHODS: A total of 100 patients with a solid renal mass who were scheduled for operation were prospectively evaluated. CT was performed before radical or partial nephrectomy. Biopsy of the surgical specimens was done twice through the tumor using an 18 gauge biopsy gun. Specimens were sent for permanent section and review by 2 pathologists blinded to each other and to the whole tissue specimens. Images were reviewed by 2 radiologists blinded to each other and to the results of pathological analysis. Results of CT and permanent biopsy were compared with the results of whole tissue specimen analysis. RESULTS: Specimens were obtained from 59 radical and 41 partial nephrectomies. Malignant neoplasms were present in 85 patients (85%). Overall accuracy was 77% and 72%, the nondiagnostic rate was 20% and 21%, sensitivity was 81% and 83%, and specificity was 60% and 33%. For the 2 radiologists overall accuracy was 60% and 66%, the nondiagnostic rate was 31% and 23%, sensitivity was 70% and 77%, and specificity was 20% and 20%, respectively. CONCLUSIONS: Overall permanent biopsy results were accurate in more than 72% of cases and CT was accurate in more than 60%. However, because the nondiagnostic rate for CT and needle biopsy was 20% and 31%, respectively, and specificity was low, we do not recommend routine preoperative CT and subsequent needle biopsy to guide treatment decision making. Rather, cases must be decided individually.

Adult↗

Evaluation of renal causes of hypertension.

There are many renal causes of hypertension. Although RAS is the most common, other renal lesions can result in hypertension. Any evaluation of the kidney for hypertension should take all of these potential renal etiologies into consideration.

Diagnostic Imaging↗

CT urography and MR urography.

CT urography and MR urography are an evolving concept and developing technique. As the technology matures, CT urography will combine the ultimate diagnostic capabilities of intravenous urography and CT. In the near future, many intravenous urograms will be replaced by CT urography to evaluate patients with hematuria and other genitourinary conditions. MR urography currently serves as an alternative imaging technique to intravenous urography and CT urography for children and pregnant women and for patients with contraindications to iodinated contrast media.

Contrast Media↗

Renal structure in early autosomal-dominant polycystic kidney disease (ADPKD): The Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) cohort.

BACKGROUND: Autosomal-dominant polycystic kidney disease (ADPKD) is characterized by gradual renal enlargement and cyst growth prior to loss of renal function. Standard radiographic imaging has not provided the resolution and accuracy necessary to detect small changes in renal volume or to reliably measure renal cyst volumes. The Consortium for Radiologic Imaging Studies in Polycystic Kidney Disease (CRISP) is longitudinally observing ADPKD individuals using high-resolution magnetic resonance (MR) imaging to determine if change in renal and cyst volumes can be detected over a short period of time, and if they correlate with decline in renal function early in disease. METHODS: Standardization studies were conducted in phantoms and four subjects at each participating clinical center. After, in the full-scale protocol, healthy ADPKD individuals 15 to 45 years old with creatinine clearance>70 mL/min underwent standardized MR renal imaging, renal iothalamate clearance, comprehensive clinical evaluation, and determination of 24-hour urinary albumin and electrolyte excretion. Stereology was used from T1-weighted images to quantify renal volume, and region-growing thresholding was used from T2-weighted images to determine cyst volume. Renal structures were evaluated in relation to demographic, clinical, and biochemical variables using means/medians, standard deviations, and Pearson correlations. RESULTS: Reliability coefficients for MR renal and cyst volume measurements in phantoms were 99.9% and 89.2%, respectively. In the full-scale protocol, 241 ADPKD individuals (145 women and 96 men) were enrolled. Total renal, cyst, and % cyst volume were significantly greater in each decade group. Hypertensive individuals demonstrated greater renal, cyst, and % cyst volume than normotensive subjects. Age-adjusted renal (r = -0.31, P < 0.0001), cyst (r = -0.36, P < 0.0001), and % cyst volume (r = -0.35, P < 0.0001) were inversely related to glomerular filtration rate (GFR). Age-adjusted renal volume (r = 0.42, P < 0.0001), cystic (r = 0.39, P < 0.0001, and % cyst volume (r = 0.41, P < 0.0001) were related with urinary albumin excretion. CONCLUSION: MR measures of renal and cyst volume are reliable and accurate in patients with ADPKD. ADPKD is characterized by significant cystic involvement that increases with age. Structure (renal and cyst volume) and function (GFR) are inversely related and directly related with the presence of hypertension and urinary albumin excretion in individuals with normal renal function.

Adolescent↗