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Dive into the research topics where Mark A. Kliewer is active.

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Featured researches published by Mark A. Kliewer.


American Journal of Medical Genetics Part A | 2007

Cornelia de Lange syndrome: clinical review, diagnostic and scoring systems, and anticipatory guidance.

Antonie D. Kline; Ian D. Krantz; Annemarie Sommer; Mark A. Kliewer; Laird G. Jackson; David Fitzpatrick; Alex V. Levin; Angelo Selicorni

Cornelia de Lange syndrome (CdLS), also known as Brachmann‐de Lange syndrome, is a well‐described multiple malformation syndrome typically involving proportionate small stature, developmental delay, specific facial features, major malformations (particularly the cardiac, gastrointestinal and musculoskeletal systems), and behavioral abnormalities. There is a broad spectrum of clinical involvement, with increasing recognition of a much milder phenotype than previously recognized. Significant progress has been made in recent years in the clinical and molecular delineation of CdLS, necessitating a revision of the diagnostic criteria, more inclusive of the milder cases. In addition, a scoring system of severity has been found to correlate with specific brain changes. Thus, a clinical overview and recommendations for anticipatory guidance are timely in aiding caretakers and professionals to individualize care decisions and maximize developmental potential for individuals with CdLS. These guidelines are derived from consensus based on collective experience of over 500 patients with CdLS, observations of the natural history in children, adolescents, and adults, a review of the literature, and contacts with national support organizations in North America and Europe.


Physics in Medicine and Biology | 2008

Preliminary in vivo atherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

Hairong Shi; Carol Mitchell; Matthew McCormick; Mark A. Kliewer; Robert J. Dempsey; Tomy Varghese

In this paper, we explore two parameters or strain indices related to plaque deformation during the cardiac cycle, namely, the maximum accumulated axial strain in plaque and the relative lateral shifts between plaque and vessel wall under in vivo clinical ultrasound imaging conditions for possible identification of vulnerable plaque. These strain indices enable differentiation between calcified and lipidic plaque tissue utilizing a new perspective based on the stiffness and mobility of the plaque. In addition, they also provide the ability to distinguish between softer plaques that undergo large deformations during the cardiac cycle when compared to stiffer plaque tissue. Soft plaques that undergo large deformations over the cardiac cycle are more prone to rupture and to release micro-emboli into the cerebral bloodstream. The ability to identify vulnerable plaque, prone to rupture, would significantly enhance the clinical utility of this method for screening patients. We present preliminary in vivo results obtained from ultrasound radio frequency data collected over 16 atherosclerotic plaque patients before these patients undergo a carotid endarterectomy procedure. Our preliminary in vivo results indicate that the maximum accumulated axial strain over a cardiac cycle and the maximum relative lateral shift or displacement of the plaque are useful strain indices that provide differentiation between soft and calcified plaques.


Abdominal Imaging | 1999

Ovarian cyst rupture causing hemoperitoneum: imaging features and the potential for misdiagnosis

Barbara S. Hertzberg; Mark A. Kliewer; Erik K. Paulson

AbstractBackground: To describe the spectrum of imaging findings and clinical presentations produced after rupture and hemorrhage of an ovarian cyst. Methods: Imaging studies and hospital records of nine patients who were ultimately diagnosed with hemoperitoneum from a ruptured ovarian cyst were reviewed and categorized. Results: Hemoperitoneum from a ruptured ovarian cyst presented a range of imaging findings. Although the imaging findings were dominated by hemoperitoneum, at least a vestige of the cyst could be identified in seven patients. The diagnosis of hemoperitoneum from a ruptured ovarian cyst was favored in only four of nine patients after the initial imaging study. Conclusions: A ruptured ovarian cyst can produce massive hemoperitoneum, with clinical symptomatology and sonographic features that closely mimic those of other disorders, in particular ectopic pregnancy. Considering the likelihood of both clinical and radiologic misdiagnosis, the radiologist should consider and pursue the diagnosis of a ruptured hemorrhagic ovarian cyst in a woman of child-bearing age who presents with pelvic pain and a large amount of complicated intraperitoneal fluid.


American Journal of Roentgenology | 2006

Radiofrequency Ablation of Peripheral Liver Tumors: Intraperitoneal 5% Dextrose in Water Decreases Postprocedural Pain

J. Louis Hinshaw; Paul F. Laeseke; Thomas C. Winter; Mark A. Kliewer; Jason P. Fine; Fred T. Lee

OBJECTIVE Our objective was to evaluate the clinical efficacy of the intraperitoneal instillation of 5% dextrose in water (D5W) during radiofrequency ablation of peripheral liver tumors for decreasing postradiofrequency pain and narcotic use. MATERIALS AND METHODS This case-control study compared the hospital course of the last 20 patients to undergo radiofrequency ablation of peripheral liver tumors at our institution. Ten consecutive subjects in the D5W group (seven women and three men; age range, 37-78 years; mean, 58 years) were pretreated with intraperitoneal D5W (average, 963 +/- 436 [SD] mL) before the ablation. This group was compared with a control group of 10 patients (five men and five women; age range, 36-73 years; mean, 54 years) who did not receive intraperitoneal D5W. The size of the ablation zone, degree of liver capsule involvement, number of burns, patient-reported pain, patient-controlled analgesia use, and length of hospital stay were recorded and compared between the groups. RESULTS The patients in the D5W group reported significantly less pain in the first 24 hr after the procedure than did the controls (2.3 vs 6.3, p = 0.003) despite a significant decrease in patient-controlled analgesia use (17.3 vs 125.1 mg of morphine, p = 0.003). The differences in pain and patient-controlled analgesia use were greatest in the first 16 hr and decreased over time in both groups. The total volume of ablation (61.9 vs 45.2 cm(3), p = 0.44), liver surface involvement (6.2 vs 6.0 cm, p = 0.73), and number of burns (1.8 vs 1.1, p = 0.14) were slightly higher in the D5W group than in the control group, but this difference was not statistically significant. CONCLUSION Pretreatment with intraperitoneal D5W before radiofrequency ablation of peripheral liver tumors decreased pain, narcotic use, and length of hospital stay. The effect of pretreatment with D5W is greatest in the first 16 hr after the procedure.


Schizophrenia Research | 2001

Outcome in children with fetal mild ventriculomegaly : a case series

John H. Gilmore; Julia Van Tol; Hellen Lewis Streicher; Kwanna Williamson; Sherry B Cohen; Robert S. Greenwood; H. Cecil Charles; Mark A. Kliewer; J. Kenneth Whitt; Susan G. Silva; Barbara S. Hertzberg; Nancy C. Chescheir

Mild enlargement of the lateral ventricles is associated with schizophrenia and other neurodevelopmental disorders. While it has been hypothesized that ventricle abnormalities associated with neurodevelopmental disorders arise during fetal brain development, there is little direct evidence to support this hypothesis. Using ultrasound, it is possible to image the fetal ventricles in utero. Fetal mild ventriculomegaly (MVM) has been associated with developmental delays in early childhood, though longer-term neurodevelopmental outcome has not been studied. Follow-up of five children (aged 4--9 years) with mild enlargement of the lateral ventricles on prenatal ultrasound and two unaffected co-twins is reported: one child had attention deficit hyperactivity disorder (ADHD), one had autism, and two had evidence of learning disorders. These cases suggest that the mild enlargement of the lateral ventricles associated with these neurodevelopmental disorders arises during fetal brain development and can be detected with prenatal ultrasound. In addition, the presence of mildly enlarged, asymmetric ventricles in two children on prenatal ultrasound and on follow-up MRI at age 6 years indicates that ventricle structure present in utero can persist well into childhood brain development. The study of fetal ventricle development with ultrasound may provide important insights into neurodevelopmental disorders and allow the identification of children at high risk.


Journal of Computer Assisted Tomography | 2002

Pseudoenhancement of simple renal cysts: a comparison of single and multidetector helical CT.

Joan P. Heneghan; Audrey L. Spielmann; Douglas H. Sheafor; Mark A. Kliewer; David M. DeLong; Rendon C. Nelson

Purpose The purpose of this work was to compare the extent of pseudoenhancement (artifactual increase in measured attenuation of a simple cyst after contrast medium administration) in a phantom model on single detector and multidetector helical CT scanners. Method The phantom consisted of four water-filled spheres varying in size from 8 to 28 mm, suspended in an aqueous contrast medium bath. Iodine concentration in the bath was varied: 0, 6, 12, and 24 mg/ml corresponding to attenuation values of 0, +108, +180, and +300 HU. The phantom was scanned on single detector and multidetector helical CT scanners during the same session. Collimation (1, 3, and 5 mm) and pitch (1 and 1.5:1, single detector; 3:1 and 6:1, multidetector) were varied at each concentration. All scans were performed at 140 kVp and 170 mA. The region of interest was measured at the center of each sphere. The effects were analyzed using a linear regression model. Results The degree of pseudoenhancement was more pronounced with increasing iodine concentration, decreasing cyst size, and wider collimation (all p = 0.0001). Pseudoenhancement was also more marked on the multidetector than the single detector scanner (p = 0.0001). At physiological levels of renal enhancement, the average pseudoenhancement was +18 HU for the single detector versus +23 HU for the multidetector scanner. Variation in pitch had no effect. Conclusion Pseudoenhancement is greater on a multidetector than a single detector helical CT scanner and may exceed 20 HU at physiological levels of renal enhancement.


Schizophrenia Research | 1998

Mild ventriculomegaly detected in utero with ultrasound : clinical associations and implications for schizophrenia

John H. Gilmore; J van Tol; Mark A. Kliewer; Susan G. Silva; Barbara S. Hertzberg; Nancy C. Chescheir

The most consistent structural abnormality of the brain associated with schizophrenia is that of mild enlargement of the lateral cerebral ventricles. Mild ventriculomegaly (MVM) of the fetal brain detected in utero with ultrasound is associated with developmental delays similar to those described in children at high risk of schizophrenia. Fetal mild ventriculomegaly may be a marker for increased risk of schizophrenia and other neurodevelopmental abnormalities. Given the association between schizophrenia and obstetrical complications, pre- and perinatal complications and pregnancy outcomes were retrospectively reviewed in 51 pregnancies in which the fetus exhibited mild ventriculomegaly on routine ultrasonography and 49 control pregnancies. Mothers of children with MVM were older than controls and had shorter gestations. There were no significant between-group differences in numbers of pregnancy complications or pregnancy outcomes as reflected in gestational age at birth, birthweight, or Apgar scores. Children with isolated mild ventriculomegaly tended to be male. This study indicates that isolated mild ventriculomegaly detected in utero is not associated with pregnancy complications and suggests that isolated mild ventriculomegaly of the fetus is genetically determined or caused by environmental events not routinely considered pregnancy complications.


Physics in Medicine and Biology | 2012

Methods for robust in vivo strain estimation in the carotid artery.

Matthew McCormick; Tomy Varghese; Xiao Wang; Carol Mitchell; Mark A. Kliewer; Robert J. Dempsey

A hierarchical block-matching motion tracking algorithm for strain imaging is presented. Displacements are estimated with improved robustness and precision by utilizing a Bayesian regularization algorithm and an unbiased subsample interpolation technique. A modified least-squares strain estimator is proposed to estimate strain images from a noisy displacement input while addressing the motion discontinuity at the wall-lumen boundary. Methods to track deformation over the cardiac cycle incorporate a dynamic frame skip criterion to process data frames with sufficient deformation to produce high signal-to-noise displacement and strain images. Algorithms to accumulate displacement and/or strain on particles in a region of interest over the cardiac cycle are described. New methods to visualize and characterize the deformation measured with the full 2D strain tensor are presented. Initial results from patients imaged prior to carotid endarterectomy suggest that strain imaging detects conditions that are traditionally considered high risk including soft plaque composition, unstable morphology, abnormal hemodynamics and shear of plaque against tethering tissue can be exacerbated by neoangiogenesis. For example, a maximum absolute principal strain exceeding 0.2 is observed near calcified regions adjacent to turbulent flow, protrusion of the plaque into the arterial lumen and regions of low echogenicity associated with soft plaques. Non-invasive carotid strain imaging is therefore a potentially useful tool for detecting unstable carotid plaque.


Experimental Lung Research | 1985

Secretion of surfactant by rat alveolar type II cells: morphometric analysis and three-dimensional reconstruction

Mark A. Kliewer; Evan K. Fram; Arnold R. Brody; Stephen L. Young

Secretion of surfactant by alveolar type II cells occurs by exocytosis and is stimulated by several mechanical and hormonal mechanisms, including beta-agonists. We examined the morphological correlates of this process by electron microscopy and by three dimensional reconstructions of rat lung alveolar epithelial type II cells before and after isoproterenol stimulation. Male rats were given a dose of isoproterenol 2 hours prior to anesthesia. The lungs were fixed by intratracheal instillation and lung tissue was processed by methods designed to enhance the retention of saturated phospholipids. The type II cells were evaluated by transmission and scanning electron microscopy and morphometry of the type II cells was performed. Three dimensional reconstruction of secretory events at the alveolar air border was also done. We observed a dose dependent increase in elliptical cell-surface pores averaging 0.2 X 0.4 micron in size on the alveolar luminal side of type II cells. Most often these pores were surrounded by an elevated area lacking microvilli and overlying an area of granular cytoplasm. The pores observed were about half the average diameter of the lamellar bodies and a deformation of that spherical secretory organelle was seen frequently. We conclude these cell-surface pores represent the structures through which surfactant is released by type II cells. During the secretion of lamellar bodies, deformation may be imposed at the restriction of the surface pores. This deformation could be important in the transformation of the lamellar material from an intracellular storage site to its active role on the alveolar surface.


Social Science & Medicine | 1982

Ghanaian national policy toward indigenous healers: The case of the Primary Health Training for Indigenous Healers (PRHETIH) program

D.M. Warren; G. Steven Bova; Mary Ann Tregoning; Mark A. Kliewer

We review the policy of the Ghanaian Ministry of Health towards indigenous healers, and estimate their potential and actual utilization in the national health delivery system. We then describe the program to give primary health training to indigenous healers. The program established relations with the regional offices and central headquarters of the Ministry of Health. The Centre for Scientific Research into Plant Medicine, the Ghana Psychic and Traditional Healers Association and various categories of indigenous healers. We describe our strategies to coordinate the program with Ministry of Health Units and different categories of indigenous healers (mainly TBAs, herbalists and priest/priestess healers) in Techiman District. We analyze the socio-cultural, economic and politico-administrative forces impinging on the design and implementation of the program to recommend ways that this kind of program can be developed in other localities within and outside Ghana.

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Tomy Varghese

University of Wisconsin-Madison

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