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Biomedical subjects

A Stillman

Publications and source records attributed to A Stillman.

13 recordsLinked to original sources

Pharmacogenomic analysis of interferon receptor polymorphisms in multiple sclerosis.

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system characterized by progressive neurological dysfunction. No curative therapy is currently available, and approximately 80-90% of afflicted individuals are ultimately disabled. Interferon beta (IFNbeta) has been shown to decrease clinical relapses, reduce brain disease activity, and possibly slow progression of disability. However, the overall effect of treatment is partial and a substantial number of patients are considered poor or nonresponders. For this report, we tested the pharmacogenomic effects of eight polymorphisms in the interferon receptor genes (IFNAR1 and IFNAR2) in a group of 147 patients undergoing open-label IFNbeta therapy. Overall, no significant differences in the distribution of responders and nonresponders, classified based on prospectively acquired primary and secondary clinical end points, were observed when stratified by any of the studied IFNAR gene polymorphisms. A trend detected with a single nucleotide polymorphism SNP 16469 (A/T) located at the third intron of the IFNAR1 gene, suggesting modest association with relapse-free status, will require confirmation in an independent data set. In addition, no significant association was observed of any of the IFNAR gene polymorphisms with susceptibility to MS, as studied by a family-based association analysis.

Adolescent↗

Trained nurses can provide safe and effective sedation for MRI in pediatric patients.

PURPOSE: To determine the success rate, safety and complications using a standard protocol and trained nurses to provide sedation for MRI under the supervision of a radiologist. MATERIALS AND METHODS: Nurses were trained to provide sedation via a standard protocol for pediatric patients undergoing diagnostic MRI. Oral chloral hydrate (80-100 mg x kg(-1)) was used for children less than 18 mo of age. Older children received either 1-6 mg x kg(-1) pentobarbital i.v., with or without 1-2 microg x kg x hr(-1) fentanyl, or 25 mg x kg(-1) thiopental pr. Sedation was defined as successful if it allowed completion of the MRI without image distorting patient movement. The records of 572 MRIs performed on 488 pediatric patients (mean age 5+/-4 yr; age 2 mo-14 yr) from 1991 to July 1995 were reviewed to determine the success rate and complications using the sedation program. RESULTS: Most, 91.8% (525/572), of the MRIs were successfully completed in 445 patients. The reasons for failure were inadequate sedation (45, 95.7%) and coughing (2, 4.2%). The failure rate was much higher before 1994 (38/272, 14%) than after (9/300, 3%; P<0.0001). Failure was more common if rectal thiopental was used (23/172, 14%) than intravenous pentobarbital (19/256, 7.4%; P<0.05). The failure rate was also high in patients with a history of a behavioural disorder (10/59, 17%). There were no deaths or unexpected admissions as a result of the sedation program. CONCLUSION: A high success rate can be achieved as experience is gained using a standard protocol and trained nurses to sedate children for MRI.

Administration, Rectal↗

Bradykinin antagonism inhibits the antigrowth effect of converting enzyme inhibition in the dog myocardium after discrete transmural myocardial necrosis.

BACKGROUND: Converting enzyme inhibitor (CEI) therapy, but not angiotensin II subtype I receptor blockade, has been shown to attenuate left ventricular remodeling in the dog after transmyocardial direct current (DC) shock. The purpose of this study was to address the importance of preservation of bradykinin to the antiremodeling effect of CEI treatment in this model. METHODS AND RESULTS: Twenty-four hours after DC shock, adult mongrel dogs were assigned to one of three groups: a control group; a group treated with ramipril 10 mg BID; and a group treated with ramipril 10 mg BID along with a continuous subcutaneous infusion of HOE 140, a bradykinin antagonist. To assess change in left and right ventricular structure, a magnetic resonance imaging (MRI) study was performed 4 weeks after DC shock and compared with a baseline MRI study performed before DC shock. The increase in left ventricular mass (mean +/- SEM) in the control group was similar to that observed in the CEI-HOE 140 group (+0.73 +/- 0.19 versus +0.75 +/- 0.18 g/kg, P = NS), but both were greater than the change in mass in the ramipril group (-0.48 +/- 0.13 g/kg, P = .004 and P = .0005, respectively). No significant change occurred in left ventricular volume or right ventricular structure in any group. Mean arterial pressure was reduced by ramipril compared with the control group (-8 +/- 2 versus +7 +/- 2 mm Hg, P = .03), and this effect was not blunted by the addition of HOE 140 (-7 +/- 3 mm Hg). CONCLUSIONS: Prevention by ramipril of the early increase in left ventricular mass in the DC shock model appears to be related to the preservation of bradykinin.

Angiotensin-Converting Enzyme Inhibitors↗

Fast anatomical imaging of the heart and assessment of myocardial perfusion with arrhythmia insensitive magnetization preparation.

A new contrast preparation based on modified driven equilibrium Fourier transfer is introduced and evaluated for generation of T1-weighted images for assessment of the myocardial perfusion with contrast agent first-pass kinetics. The new preparation scheme produces T1 contrast with insensitivity to arrhythmias in prospectively triggered sequential imaging thereby eliminating one of the major sources of problems in potential patient studies with previously employed contrast preparations schemes.

Algorithms↗

Relative effects of alpha 1-adrenoceptor blockade, converting enzyme inhibitor therapy, and angiotensin II subtype 1 receptor blockade on ventricular remodeling in the dog.

BACKGROUND: Progressive ventricular remodeling after myocardial damage is associated with a poor prognosis. Optimal prevention of the histopathological processes involved in remodeling requires a more complete understanding of the mechanisms involved in initiating and maintaining these structural changes. Since the sympathetic nervous system and the renin-angiotensin system may be involved in the remodeling process, the structural effects of pharmacological inhibitors have been evaluated in a canine model of localized myocardial injury resulting from transmyocardial DC shock. METHODS AND RESULTS: The study is comprised of two protocols run in series. In protocol 1, zofenopril (Z), a converting enzyme inhibitor (CEI), prevented the increase in left ventricular mass (LVM) and end-diastolic volume (LVV) observed in the control group (C) at 16 weeks (Z: LVM, 69.8 +/- 3.4 to 65.4 +/- 2.6 g, P = NS; LVV, 45.4 +/- 2.7 to 51.6 +/- 2.7 mL, P = NS; C: LVM, 68.4 +/- 3.2 to 91.4 +/- 2.9 g, P = .0001; LVV, 56.6 +/- 3.0 to 71.9 +/- 2.4 mL, P = .0003). Terazosin, an alpha 1-adrenoceptor antagonist, failed to prevent remodeling at 16 weeks despite continued receptor blockade. In protocol 2, the antiremodeling effect of full-dose CEI therapy with ramipril was confirmed. Low-dose ramipril that exerted no hemodynamic effect failed to prevent remodeling (LVM, 89.7 +/- 4.6 to 105.7 +/- 3.4 g, P = .01; LVV, 61.8 +/- 3.8 to 76.8 +/- 3.3 mL, P = .002). An angiotensin II subtype 1 receptor blocker also failed to prevent the increase in LVM or LVV (LVM, 89.0 +/- 4.6 to 109.7 +/- 5.3 g, P = .0001; LVV, 66.0 +/- 1.9 to 78.4 +/- 3.6 mL, P = .007). CONCLUSIONS: High-dose CEI therapy can prevent progressive structural changes resulting from localized myocardial damage induced by DC shock. the failure of alpha 1-adrenoceptor blockade and angiotensin II subtype 1 blockade to attenuate remodeling argues against an important direct role for norepinephrine acting through alpha 1-receptors or angiotensin II acting through the type 1 receptor in the remodeling process in this model.

Adrenergic alpha-Antagonists↗

A look at ear canal changes with jaw motion.

Two procedures were used with one subject to examine changes in the ear canal with jaw motion. Silicone ear impressions were examined to measure the effect of jaw position. Magnetic resonance imaging was used to define the three-dimensional structure of the canal and visualize key underlying tissue. Results showed that inexpensive impressions can detail changes in the cartilaginous region of the canal. Approximately a 25% change in this subject's ear canal with different jaw positions was observed in the anterior/posterior plane with essentially no change in the superior/inferior plane. This is likely related to asymmetric stress from action of the mandibular condyle on neighboring cartilaginous tissue. Solutions to jaw motion-induced feedback problems are suggested.

Ear Canal↗

Assessment of clinical skills of residents utilizing standardized patients. A follow-up study and recommendations for application.

OBJECTIVE: To determine the reliability and validity of "standardized patients" to assess clinical performance of internal medicine residents. DESIGN: Each resident spent 2 half-days interacting with 19 standardized patients (nonphysicians taught to portray patients in a reproducible fashion). Each resident was asked to obtain focused histories, perform relevant physical examinations, and provide patient education or counseling. At the end of each 10- to 15-minute encounter, the resident was asked to identify positive findings on physical examination and to prioritize a differential diagnosis. Other, more traditional indicators of clinical skills were also obtained. PARTICIPANTS: Three hundred ten residents from nineteen internal medicine training programs in the New England region of the United States. RESULTS: Reproducible estimates of data gathering and interviewing skills were achieved with 1 day of testing. Validity analyses were difficult to interpret because of the lack of an external "gold standard." However, faculty judgments of performance from reviewing videotapes corresponded with standardized-patient-based scores. Differences in group performance were also demonstrated across years of training and between U.S. or Canadian and foreign medical graduates. CONCLUSIONS: Systematic and effective procedures for developing standardized-patient-based test materials and for training standardized patients have been developed. This technique is best used for measuring data gathering and interviewing skills. Correlations with commonly used evaluation methods were generally low; this may be because standardized patients measure different skills. Local use of this technique by residency programs and the development of regional consortia sharing resources, costs, and expertise are advocated.

Clinical Competence↗

Reye's syndrome in the adult: case report and review of the literature.

A 22-year-old male presented with a brief history of progressive encephalopathy. One week previously, he had developed an upper respiratory infection that resolved spontaneously and was followed by intractable vomiting. He had taken salicylates for several days during the viral syndrome. The diagnosis of Reye's syndrome was confirmed by hepatic histology. Aggressive conservative management was followed by complete metabolic and neurological recovery. There are fewer than 10 reported cases of Reye's syndrome in adults but this disease may be more common than is generally suspected. The diagnosis should be considered in patients presenting with emesis and obtundation, who have recently had a viral illness and exhibit elevated blood ammonia and transaminases with normal cerebrospinal fluid. Confirmation is achieved by liver biopsy. Therapy is directed toward aggressive reduction of increased intracranial pressure.

Adult↗