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Biomedical subjects

D Berg

Publications and source records attributed to D Berg.

At least 37 records · Page 2Linked to original sources
PubMed2001

Virtual reality simulators for dermatologic surgery: measuring their validity as a teaching tool.

Surgical simulation is increasingly being considered for training, testing, and possibly credentialing in medicine and surgery. At the University of Washington we have been developing a virtual reality (VR) suturing simulator. In the course of development it must be realized that expensive new technologies should bear the burden of proof of their effectiveness and reliability before they are put into training programs. The purpose of this article is to define the concept of surgical skill and to discuss how it can be measured in the context of validating VR surgical simulators. Specific measures of validity and reliability are reviewed and discussed.

Computer Simulation↗
PubMed2001

Evidence-based medicine for dermatologic surgeons: concepts in critical appraisal of information.

BACKGROUND: The term evidence-based medicine (EBM) is increasingly being used. Physicians, journal editors, insurance companies, and patients are applying its tenets to clinical decision making. Although there are concerns about the overly zealous application of EBM to clinical situations, many of the basic concepts are important in improving decision making. OBJECTIVE: To define evidence-based medicine and to review potential problems in basing decision making entirely on less-than-ideal evidence. METHODS: We reviewed the EBM literature and looked for examples in dermatology of pitfalls in decision making based on poor evidence. RESULTS: Following a definition of EBM, we review problems inherent in anecdotes and uncontrolled trials, including the placebo effect. Examples of medical practice that have been altered by doing more rigorous studies are provided. CONCLUSIONS: Concepts of EBM as currently defined should be considered by dermatologic surgeons in assessing the available information for clinical decision making.

Clinical Trials as Topic↗
PubMed2001

A simple tool for teaching flap design with digital images.

BACKGROUND: Defects created by excision or Mohs micrographic surgery must be analyzed and surgical options including flaps must be considered. Teaching flap design to dermatology trainees is often done at the bedside of the patient with the trainee describing or marking a proposed flap. Open discussion of the options in this way is sometimes unnerving for the patient. Blackboard discussions or drawings are limited in their realism. OBJECTIVE: To describe a rapid, simple method using commonly available software to allow a trainee to draw and redraw a proposed flap on a digital image of the defect without the time and cost of printing. METHODS: We describe a feature in the widely used presentation program Microsoft PowerPoint which can be used to draw on an imported digital image in various colors. RESULTS: A digital photograph taken at the bedside can quickly be loaded into PowerPoint and viewed as a full-screen picture on a computer. Using an electronic pen, multiple lines can be drawn and erased on the picture, allowing surgical planning and teaching away from the bedside. CONCLUSION: Design and analysis of potential incision lines for a flap can be done quickly using a digital image and commonly available software, allowing a new option for teaching flap design.

Dermatology↗
PubMed2001

Differences in substantia nigra echogenicity of nosological subtypes within the schizophrenic spectrum. A preliminary transcranial ultrasound study.

OBJECTIVE: Schizophrenic patients treated with neuroleptic drugs often develop neuroleptic-induced parkinsonism (NIP). Here, transcranial sonography (TCS) was used to test for differences in the susceptibility to NIP related to the echogenicity of the substantia nigra (SN) in different schizophrenic subforms. METHODS: 79 patients with schizophrenic spectrum psychoses treated by neuroleptic drugs and diagnosed according to ICD-10 and Leonhard's nosology were examined independently by TCS and, clinically, for NIP. RESULTS: Patients with larger echogenic SN had more severe NIP (p < 0.05). Diagnostic categories according to ICD-10 did not differ significantly in SN echogenicity (p > 0.2), whereas Leonhard's did (p < 0.05). CONCLUSIONS: These findings suggest altered SN echogenicity in subtypes of the schizophrenic spectrum. The putative role of the nigrostriatal system in the etiology of schizophrenic subtypes is discussed.

Adult↗
PubMed2001

Fungal skin infections in children. New developments and treatments.

Recognizing the common manifestations of pediatric fungal infections is a key part of any primary care practice. Of paramount importance is the clinical acumen of the physician. In this article, Drs Berg and Erickson discuss several types of fungal infections in children, identify tools for diagnosis, and outline the most effective options for treatment. Newer "off-label" therapies are also examined.

Administration, Cutaneous↗
PubMed2001

Reduction of Menkes mRNA and copper in leukocytes of patients with primary adult-onset dystonia.

Studies on postmortem tissue of patients with primary adult-onset dystonia revealed a significant increase in copper levels and a reduction of copper transporting Menkes protein of the lentiform nuclei. Here we demonstrate that patients with idiopathic adult-onset cervical dystonia (n = 14) have reduced Menkes mRNA copies and lower copper levels in leukocytes compared to controls (n = 17; U test, p < 0.05). Changes were less distinct in patients with blepharospasm. Therefore, disturbances of copper metabolism in focal dystonia may not be restricted to the basal ganglia.

Adenosine Triphosphatases↗
PubMed2001

Issues in validation of a dermatologic surgery simulator.

At the University of Washington, we have been developing a suturing simulator using novel finite element model techniques which allow real-time haptic feedback. The issues involved in measuring validity in a suturing model have not been examined in a systematic way. Very few studies exist on the surgical factors that lead to good sutures. We have examined published data on these factors as well as previously studied metrics in suture training. This information has been combined with a review of types of validity (e.g., face, construct, predictive and concurrent) and reliability that must be considered in assessing any surgical simulator.

Computer Simulation↗
PubMed2000

Genetic analysis of the alpha2-macroglobulin gene in early- and late-onset Parkinson's disease.

Recent association studies investigating polymorphisms in the alpha2-macroglobulin (A2M) gene provided evidence for an involvement of this protease inhibitor in the pathogenesis of Alzheimer's disease (AD). The partially overlapping pathology between AD and Parkinson's disease (PD) led us to investigate the role of A2M in PD. We performed association studies in a large sample of 328 German PD patients and 322 closely matched healthy controls. Analyzing the Val1000Ile polymorphism and a pentanucleotide deletion in the 5' splice site of exon 18 of the A2M gene we found an excess of homozygosity for the A2M deletion in early-onset PD (EOPD) patients (age at onset < 50 years) compared to late-onset PD (LOPD) patients (age at onset > 50 years; p = 0.008, p(p)c = 0.064, chi2 = 7.017). Therefore our data might indicate an age at onset modulating effect of the homozygous A2M deletion in PD.

Age of Onset↗
PubMed2000

Mutation analysis and association studies of the UCHL1 gene in German Parkinson's disease patients.

Recently, an Ile93Met substitution has been identified in the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) gene in a single German PD family with autosomal dominant inheritance. To determine whether mutations in the UCHL1 gene are causative for Parkinson's disease (PD) a detailed mutation analysis was performed in a large sample of German sporadic and familial PD patients. We found no disease-causing mutation in the coding region of the UCHL1 gene. Direct sequencing revealed six intronic polymorphisms in the UCHL1 gene. Analysis of an S18Y polymorphism in exon 3 of the UCHL1 gene in sporadic PD patients and controls showed carriers of allele 2 (tyrosine) significantly less frequent in patients with a reduced risk of 0.57 (CI = 0.36-0.88; p = 0.012, p(c) = 0.047, chi2 = 6.31). Our study shows that sequence variations in the coding region of UCHL1 are a rare event. A protective effect of a certain UCHL1 variant in the pathogenesis of sporadic PD is suggested, underlining the relevance of UCHL1 in neurodegeneration.

Aged↗
PubMed2000

A phase I study of gemcitabine and docetaxel in patients with metastatic solid tumors.

BACKGROUND: A Phase I study was initiated to determine the maximum tolerated dose of weekly gemcitabine combined with monthly, fixed-dose docetaxel. METHODS: Patients with metastatic solid tumors were treated with docetaxel, 60 mg/m(2), on Day 1 every 28 days. Gemcitabine was administered on Days 1, 8, and 15 and underwent dose adjustment in cohorts of 3-6 patients. At the maximum tolerated dose, 11 additional patients were enrolled. RESULTS: Twenty-six patients received 85 cycles of therapy. At the first dose level, the planned gemcitabine dose on Days 1, 8, and 15 was 800 mg/m(2). Two of the 6 patients treated at this dose level experienced dose-limiting toxicities (DLTs) requiring the reduction of gemcitabine to 600 mg/m(2) per dose and the administration of ciprofloxacin, 500 mg orally twice daily, on Days 8-18. At the second dose level the first 3 patients experienced no DLTs and the dose of gemcitabine was increased to 700 mg/m(2). Two of the 6 patients treated at the 700 mg/m(2) dose level experienced DLTs. Eleven additional patients were enrolled at the recommended Phase II dose of gemcitabine (600 mg/m(2)). At this dose level, Grade 3/4 (according the National Cancer Institute's common toxicity criteria) neutropenia and thrombocytopenia occurred in 12.5% and 2.1% of cycles, respectively. Grade 3 and 4 nonhematologic toxicities were uncommon. Three of seven evaluable patients with pancreatic carcinoma had evidence of significant antineoplastic activity (three partial responses). In addition, two complete responses (one patient with gastric carcinoma and one patient with ovarian carcinoma) and one partial response (patient with hepatocellular carcinoma) were noted in patients with other solid tumors. CONCLUSIONS: The regimen comprised of docetaxel, 60 mg/m(2), on Day 1 and gemcitabine, 600 mg/m(2), on Days 1, 8, and 15 with ciprofloxacin on Days 8-18 every 28 days is safe, well tolerated, and active.

Antimetabolites, Antineoplastic↗
PubMed2000

The correlation between ventricular diameter measured by transcranial sonography and clinical disability and cognitive dysfunction in patients with multiple sclerosis.

CONTEXT: Magnetic resonance imaging (MRI) data suggest that the extent of brain atrophy in patients with multiple sclerosis (MS) is related to the severity of disease. OBJECTIVE: To evaluate whether ventricular diameter determined by transcranial sonography (TCS) is a marker of brain atrophy and is correlated with disability, cognitive performance, and mood. SUBJECTS AND METHODS: We examined 74 subjects with MS and 74 age- and sex-matched control subjects with TCS and assessed the transverse diameter of the third ventricle and the frontal horns of the lateral ventricles. Quantitative neurological examination was performed in subjects with MS using the Expanded Disability Status Scale. All subjects with MS underwent MRI, the Brief Repeatable Battery of Neuropsychological Tests for MS, and standardized tests for mood disorders. RESULTS: Transcranial sonographic measurements of ventricular diameter closely matched MRI measurements (Spearman rank correlation, r=0.7-0.9; P<.01). The ventricular diameters were significantly larger in subjects with MS than in healthy age- and sex-matched control subjects. The measurement of the diameter of the third ventricle obtained by TCS or MRI and the measurement of disability obtained with the Expanded Disability Status Scale were significantly correlated (Spearman rank correlation, r = 0.4; P<.01). The correlation between the diameter of the frontal horns and disability was substantially lower for both neuroimaging techniques. In addition, TCS and MRI data correlated significantly with the majority of neuropsychological tests; no correlation was found between the diameter of the ventricles and depression scales. CONCLUSION: As ventricular diameter is related to the status of disability and may also indicate disease progression, we propose measurement of the diameter of the third ventricle with TCS as a quick and easy surrogate marker for serial follow-up examinations in patients with MS.

Adult↗
PubMed2000

The basal ganglia in haemochromatosis.

Haemochromatosis is characterised by deposition of iron-containing pigment in various organs, but little is known about possible deposition in the brain and its clinical impact. We therefore investigated 14 patients with hereditary haemochromatosis with MRI, CT and transcranial ultrasound (TCS) and examined them neurologically. In six of the patients dense lesions were found within the lentiform nucleus on CT, all of whom displayed hyperechogenic lesions in the same area on TCS, as did one other patient. In these patients the relative signal intensities of the lentiform nucleus measured by MRI relaxometry were higher. No patient had clinical signs of basal ganglia disorders.

Adult↗
PubMed2000

Genetic analysis of immunomodulating factors in sporadic Parkinson's disease.

Immunomodulating factors have been shown to play a role in the pathogenesis of Parkinson's disease (PD) by biochemical methods. In order to investigate functionally important genes of the tumor necrosis factor alpha (TNFalpha) pathway we studied the frequency of DNA polymorphisms in the interleukin 6 (IL6), the TNFalpha, and the TNFalpha receptor 1 (TNFR1) genes in 264 sporadic German PD patients and in 183 age and sex matched German healthy controls. Analyzing the TNFalpha-308 polymorphism we found heterozygous individuals carrying alleles 1 and 2 more frequently in patients with a relative risk of 1.56 (p = 0.046, p(c) = 0.13, chi2 = 3.98). In contrast, the frequency of the B/2 haplotype described by the TNFR1-609 and TNFRI+36 polymorphisms was significantly decreased in our PD patients group (p = 0.0097, p(c) = 0.048, chi2 = 6.69) with a relative risk reduced to 0.52. Our results suggest an involvement of immunomodulating factors in the pathogenesis of sporadic PD as revealed by a molecular genetic approach.

Adjuvants, Immunologic↗
PubMed2000

Virtual reality for dermatologic surgery: virtually a reality in the 21st century.

In the 20th century, virtual reality has predominantly played a role in training pilots and in the entertainment industry. Despite much publicity, virtual reality did not live up to its perceived potential. During the past decade, it has also been applied for medical uses, particularly as training simulators, for minimally invasive surgery. Because of advances in computer technology, virtual reality is on the cusp of becoming an effective medical educational tool. At the University of Washington, we are developing a virtual reality soft tissue surgery simulator. Based on fast finite element modeling and using a personal computer, this device can simulate three-dimensional human skin deformations with real-time tactile feedback. Although there are many cutaneous biomechanical challenges to solve, it will eventually provide more realistic dermatologic surgery training for medical students and residents than the currently used models.

Computer Simulation↗
PubMed2000

Transcranial sonography of the brain parenchyma: comparison of B-mode imaging and tissue harmonic imaging.

Transcranial color-coded Duplex sonography (TCCS) has been used for the identification of cerebrovascular disorders. Recently, its value in the diagnosis of disorders of the brain parenchyma has been proposed. The object of this study was to determine systematically the echo pattern of the brain parenchyma and to compare conventional B-mode imaging with tissue harmonic imaging (THI). Transcranial sonography (TCS) was performed in 54 healthy individuals through the temporal bone window using conventional B-mode imaging and THI by two experienced investigators. Identification rates for several brain structures were assessed, and the quality of depiction of each method was graded semiquantitatively. In addition, several parts of the ventricular system and the basal cerebral cisterns were measured. Four subjects did not have an adequate bone window for transcranial examination. In the remaining people, the bone window was assessed to be adequate (59%) or excellent (33%). In the majority (> 80%), TCS allowed an unequivocal identification of various brain structures. Inter-rater variability of the assessments of tissue echogenicity and measurements of the ventricular width were found to be low for several structures (e.g., brainstem, thalamus, or 3rd ventricle). The echo pattern of brain tissue in THI is identical to that described for B-mode imaging. Using THI, contours of brain structures were typically visualized more clearly and the reproducibility of measurements was more consistent. In our experience, insonation of the contralateral lobes was limited when depths were higher than 12 cm using THI. In conclusion, TCS allowed the sonographic examination of the brain parenchyma in the majority of our subjects. THI substantially improves the identification of parenchymal structures when the depth is below 12 cm.

Adult↗
PubMed2000

Early natural course of transient encephalopathy after coronary artery bypass grafting.

OBJECTIVE: A decline of neuropsychological performance is an unwanted side effect of coronary artery bypass grafting (CABG) with extracorporeal circulation. There is little data on the neuropsychological changes during the first 2 wks after CABG. DESIGN, SETTING, PATIENTS: In this prospective observational study at our university medical center, a group of 67 patients who underwent routine CABG was selected for absence of comorbidity (such as carotid stenosis, previous stroke, dementia, and advanced general medical disorders) and examined. In this selected group of patients, no focal deficit was seen throughout the study. A total of 20 hospitalized patients with different types of peripheral neuropathy and free from drugs interfering with cognition served as a control group for the practice effects of the neuropsychological testing. MEASUREMENTS AND MAIN RESULTS: Seven standard tests covering different neuropsychological domains were used as a composite battery. Examinations took place before surgery and serially at days 3, 6, and 9 after CABG; general neurologic examination was done every day, including the first postoperative day. We observed a definite decline in all tests at day 3 (p < .01) and progressive recovery thereafter up to or even beyond preoperative values within 9 days (p < .01). Transient depression as indicated by self-rated scores occurred in some patients. CONCLUSION: We observed a uniform, but transient, deterioration in performance on a battery of frequently repeated standardized neuropsychological tests early after CABG. Our data on the early natural course may help to better evaluate treatment efforts aimed at preventing or reducing after-surgery neuropsychological alterations.

Adult↗