Renal osteodystrophy in course of periodic dialysis for chronic uremia.
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Biomedical subjects
Publications and source records attributed to D Kim.
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Two cases of spontaneous dissection of hepatic arteries are described. Presentation and management of these two patients are distinctly different. The first patient presented with mild back pain and mild abnormal liver function tests and was treated conservatively. The second patient presented with hemoperitoneum and shock and was treated surgically.
Percutaneous transluminal angioplasty was performed on a right common iliac artery stenosis presumed to be causing renovascular hypertension in a patient with a renal allograft anastomosis to the right external iliac artery. This was complicated by an obstructive dissection resulting in acute threatening renal allograft ischemia. Renal blood flow was restored by means of a transluminal reperfusion catheter until corrective surgery could be performed. This case is reported because such catheters can be acutely helpful to the interventionalist, and they have not been described in the radiology literature.
We describe a patient with a false aneurysm of the lingual artery of uncertain etiology and present the ultrasound, computed tomography and angiographic findings.
A study was carried out to evaluate: (a) the value of a cumulative exposure estimate (CEE) calculated from limited information on air concentration; and (b) whether chronic exposure to mixed organic solvents at a shoe manufacturing factory has induced neurobehavioral changes. The Neurobehavioral Core Test Battery was administered to 40 female workers from a shoe manufacturing factory and 28 housekeepers as referents. The airborne concentrations of the solvents as a mixture were 0.46-0.71 at the frame making process and 1.83-2.39 at the adhesive process. Performance was analyzed by three exposure indices: current department, exposure duration, and CEE. The Santa Ana Dexterity test showed statistically significant differences only in CEE. In particular, the group with higher exposures had a significantly poorer performance than the reference group, on preferred hand trials. The results suggested that CEE appeared to be a better indicator of mixed organic solvents exposure, and neurobehavioral changes were associated with CEE over 10 years.
PURPOSE: Noting a doubling in mortality soon after placement of filters in the inferior vena cava (IVC) from 1985 (7.8%) to 1992 (15.2%), the authors performed a study to define risk factors associated with death soon after IVC filter placement and to develop revised guidelines for filter placement. PATIENTS AND METHODS: During a 4-year period, 141 IVC filters were placed in 137 patients. Patients were divided into two clinical risk groups: those with possible malignancy and those with possible suprainguinal venous thrombus. Survival was monitored for up to 3 weeks after hospital discharge. RESULTS: Death occurred in 16 (26%) of 61 patients with malignancy (P = .0086, compared with patients without malignancy), seven (35%) of 20 patients with suprainguinal venous thrombus (P = .0422, compared with patients without suprainguinal venous thrombus), and six (46.2%) of 13 patients with malignancy and suprainguinal venous thrombus (P = .0091, compared with patients without malignancy or suprainguinal venous thrombus). CONCLUSION: The data indicate that for some patients with malignancy or suprainguinal venous thrombus, insertion of an IVC filter gives little or no survival benefit. A reassessment of IVC filter use in these patients is warranted.
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Clinical manifestations of atopic hand-foot (H-F) dermatitis have not been well studied. This study examined 108 atopic dermatitis (AD) patients with H-F dermatitis between May 1997 and July 1999 at our AD clinic to determine the clinical characteristics of atopic H-F dermatitis and to assess its etiologic associations. It usually began in childhood with an early onset of AD. Pruritus was the most frequent symptom, and erythema, scales, lichenification, hyperkeratosis, fissures, and keratolysis exfoliativa were also common signs. Both the hands and feet were involved in 47 (44.0%) patients, and either hand or foot involvement was observed in 15 (13.9%) and 46 (42.6%) patients, respectively. Palmar or plantar surfaces were more frequently involved than the dorsal aspects. The great toe was affected more often than the other toes. Two-thirds of patients presented with manifestations of the ichthyosis triad and sandpaper-like skin lesions on the elbow, knee, and lateral malleolus. Palmar or plantar hyperhidrosis was reported in 15% and 20%, respectively. The ichthyosis triad-associated group showed a significantly higher incidence of sandpaper-like (thickened, roughened) skin lesions, and these patients had lesions on the dorsal hands or heels and lateral malleolus more frequently than ichthyosis triad-absent patients. The hyperhidrosis-associated group showed an association with glassy lesions, localized to palmar or plantar areas. Atopic H-F dermatitis is associated with the nonallergic etiologies of AD and clinical subgroups can be identified on the basis of nonallergic backgrounds.
Despite a general understanding that bone quality contributes to skeletal fragility, very little information exits on the age-dependent fatigue behavior of human bone. In this study four-point bending fatigue tests were conducted on aging bone in conjunction with the analysis of stiffness loss and preliminary investigation of nanoindentation based measurements of local tissue stiffness and histological evaluation of resultant tensile and compressive damage to identify the damage mechanism responsible for the increase in age-related bone fragility. The results obtained show that there is an exponential decrease in fatigue life with age, and old bone exhibits different modulus degradation profiles than young bone. In addition, this study provides preliminary evidence indicating that during fatigue loading, younger bone formed diffuse damage, lost local tissue stiffness on the tensile side. Older bone, in contrast, formed linear microcracks lost local tissue stiffness on the compressive side. Thus, the propensity of aging human bone to form more linear microcracks than diffuse damage may be a significant contributor to bone quality, and age related fragility in bone.
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Random mutagenesis has been developed as an approach for the study of human cytochrome P450 (P450) enzymes and their structure and function. Sensitive screening methods are critical for the success of this approach. We have developed one system that takes advantage of the ability of human P450 1A2 to activate heterocyclic amines to mutagenic products [A. Parikh, P. D. Josephy, and F. P. Guengerich, Biochemistry, 38, 5283-5289 (1999)]. Mutants with both attenuated and enhanced activity have been recovered and subjected to further kinetic analysis. For phenacetin O-deethylation, the E225I mutant had kcat 6x > wild type; D320A had kcat 1/10x < wild type (and Km 15 x > wild type). With all three P450s, the rate of first electron reduction was similar, and all had similar binding constants for phenacetin (approximately 15 microM). All three forms yielded intermolecular, noncompetitive kinetic deuterium isotope effects of 1.5-2 [DV and D(V/K)] for O-deethylation of [OCD2CH3]-phenacetin. All three forms of P450 1A2 also formed a minor product, the acetol (C-hydroxylation of the acetyl group). This reaction had a deuterium isotope effect of approximately 14 with all three forms of the enzyme, and C-H bond breaking is the rate-determining step. Another approach to P450 2A6 involves the recent observation that this P450 can accumulate indigo [E. M. J. Gillam, A. M. A. Aguinaldo, L. M. Notley, D. Kim, R. G. Mundkowski, A. A. Volkov, F. H. Arnold, P. Soucek, J. T. DeVoss, and F. P. Guengerich, Biochem. Biophys. Res. Commun 265, 469-472 (1999)]. Current results indicate that this process involves the conversion of endogenous indole to indoxyl by the P450. The reaction may be used in assays of random mutants and has some potential applications in industry.
A method is presented for the quantitative interpretation of thallium-201 myocardial perfusion studies. The data are planar images collected immediately following the stress injection, and 4 to 6 hours later. Data analysis consists of preprocessing, including thresholding of the original data, and data reduction using a variant of the circumferential profile methods. The profiles are subdivided into segments, and for each segment the difference between the norm and the actual data is computed. This difference is a quantitative symptom, whose size is assumed to be related to the probability of having the disease. The relationship between the size of the symptom in each of nine segments (three segments/view in three views) and the probability of disease is expressed in a table in which for 30 diseases (combinations of vascular lesions) the sensitivity for each of the nine symptoms is described as a Gaussian function whose average and standard deviation are computed from previous validated cases. Using an arbitrary prevalence, the post-testing probability can then be computed using Bayes' formula sequentially. The sensitivities, however, are not expressed as a binary function of the presence or absence of a symptom, but as a distribution function defined by experience. The method is sensitive for the detection of isolated left anterior descending disease (100%) and triple vessel disease (96%). When specific combinations of vascular lesions are recognized the specificity increases from 79% (when unspecified abnormalities are recognized) to 87% when left anterior descending disease or triple vessel disease is recognized.(ABSTRACT TRUNCATED AT 250 WORDS)
Patients with extensive full-thickness burns who refuse blood transfusion present a challenge to the burn team. We have recently treated four such patients, and we achieved a successful outcome in three. Staged excision and skin graft operations with minimal blood loss were performed. Two patients were treated with erythropoietin. Patient autonomy should be accepted by the burn team, but opportunity should exist for reassessment of treatment plans.
The influence of laminin-1 (LN) and tenascin-C (TN), extracellular matrix molecules expressed spatially and temporally along the neural growth route from spiral ganglion (SG) neurons to the cochlear sensory cells, was evaluated in cultured SG explants from postnatal day 4 rats. Increasing concentrations of LN resulted in a strong, dose-dependent increase in the length of neurites and in a higher number of neural processes, while varying TN concentrations had relatively minor effects on both parameters. The results suggest differential receptor activation by LN and TN. When explants grown on LN were treated with Kistrin, an inhibitor of the alphavbeta3 integrin, the LN-induced increase in neurite length was reduced in a dose-dependent manner. However, the number of extending neurites was not affected, indicating that different receptors mediate this response, perhaps by increasing neuronal survival.
The steady-state responses of endothelial cell F-actin distribution to changes in in vivo shear stress have been well documented. The purpose of the current work was to define the dynamics of redistribution of F-actin in the period immediately after experimental changes in shear. We used abdominal aortic coarctation in rabbits to experimentally increase shear stress downstream from the coarctation by approximately twofold. In situ staining was employed to track subsequent F-actin redistribution. Within 12-15 hours, the number of stress fibers in the central regions of the cells decreased, and some separation of junctional actin in adjacent cells occurred. Long, central stress fibers of variable thickness were evident at 24 hours, but the band of actin normally seen at the periphery of the cells could no longer be distinguished. The redistribution of F-actin was completed over the next 24 hours by an increase in thickness of central stress fibers. Restoration of normal F-actin distribution after coarctations were removed proceeded more slowly. The long, thick stress fibers that were induced by high shear were replaced by thinner or shorter microfilament bundles 48 hours after the coarctations were removed. At 72 hours, central stress fibers were primarily long, thin structures. Peripheral F-actin was not fully restored at this time. Peripheral F-actin was restored at 1 week after removal of the coarctation, but there were still more and longer stress fibers at this time than were observed in control aortas.(ABSTRACT TRUNCATED AT 250 WORDS)
The propagation of polarized light through the cornea is affected by the orientations of the corneal lamellae and by the refractive imbalance between the collagen fibrils and the ground substance. Thus, well-designed measurements and analyses of polarized light propagation through the cornea can be used to obtain information regarding the cornea's lamellar and fibrillar structures. This paper shows that, for the rabbit, measured values of the optical parameters strongly suggest that the distribution of lamellae orientations is not random, but has one (or two) preferred orientation directions. Also, there is considerable evidence that collagen is intrinsically anisotropic. The Weiner formula gives the effective birefringence of an assembly of parallel isotropic fibrils and its generalization to the case of anisotropic fibrils is presented. Finally, calculations based on preferred orientation models having lamellae composed of anisotropic fibrils show that comparison with experimental values can yield structural information.