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Biomedical subjects

C Lum

Publications and source records attributed to C Lum.

15 recordsLinked to original sources

Unusual eustachian tube mass: glomus tympanicum.

SUMMARY: A case of recurrent glomus tympanicum presenting with epistaxis is described. CT and MR imaging revealed a homogeneously enhancing mass extending along the entire course of the eustachian tube, with a portion protruding into the nasopharynx. Glomus tumors tend to spread along the path of least resistance and may extend into the eustachian tube. The unique imaging appearance should place a glomus tumor high on the list of differential diagnoses.

Epistaxis↗

Synthesis of alpha-substituted beta-amino acids using pseudoephedrine as a chiral auxiliary.

[reaction: see text] beta-Amino acids are becoming increasingly attractive as intermediates in the synthesis of a variety of molecular structures. However, few methods are available for the synthesis of alpha-substituted beta-amino acids that are both readily scalable and highly stereoselective. Herein we report a new method for synthesizing alpha-substituted beta-amino acids that satisfies both of these requirements using enantiomerically pure pseudoephedrine as a chiral auxiliary.

Amino Acids↗

AUDIX: a knowledge-based system for speech-therapeutic auditory discrimination exercises.

AUDIX is a knowledge-based multimedia system for auditory discrimination exercises. The aim of AUDIX is to provide patients with a computer-based therapy system which they can use between sessions with the human therapist, at home on an 'on-demand' basis. It is centered around computer based cognitive rehabilitation therapy whereas most existing programs in this area are only used for assessment. The auditory discrimination exercise system is designed for adult people who are speech-impaired as a result of a stroke. These people have auditory perceptual problems. The nature of the perceptual problem is an inability to perceive differences between phonemes. This requires a type of therapy called auditory discrimination training. The system provides computer-based auditory discrimination training. Through the knowledge-based design the domain dependent therapy knowledge is separated from the system core and provides a way for the therapist to add new knowledge, as new stimuli, or to create a new knowledge base to provide special exercises for an individual patient. The AUDIX architecture is described and the advantages of computer-based therapy are discussed.

Adult↗

Why do some aphasics show an advantage on some tests of nonpropositional (automatic) speech?

Sixteen aphasic patients were given three pairs of tasks that compared the production of the same items in either propositional or nonpropositional contexts. A nonpropositional number production task involved counting from 1 to 10 while the propositional version of that task involved naming the Arabic numbers 1 to 10 in nonconsecutive order. A nonpropositional picture-naming task involved naming pictures with the aid of familiar phrase cues (e.g., Don't beat around the BUSH) while in the propositional version the cues were novel phrases (e.g., Don't dig behind the BUSH). Finally a nonpropositional phrase repetition task involved repeating well-known phrases while the propositional version involved repeating novel phrases. The group as a whole showed strong nonpropositional advantages for number production and picture naming with a somewhat weaker advantage for phrase repetition. Only 5 of the individual patients showed nonpropositional advantages on all three pairs of tasks: the remaining 11 patients showed a significant nonpropositional advantage on one or two of the pairs of tasks, but not on all three. All of the patients showed a nonpropositional advantage on at least one pair of tasks, and there were no examples of better performance on the propositional than on the nonpropositional version of any task. Contrasting patterns of performance seen in different patients was related to their performance on a battery of cognitive and linguistic tasks that was given to each patient.

Adult↗

Giant-cell tumor of the skull base.

Giant cell tumors are uncommon primary bone tumors. They primarily occur in the long bones. Giant cell tumors are extremely rare in the skull and head and neck. When it does occur, the maxilla and mandible are the common sites to be involved. We described two cases of giant cell tumor in the temporal bone. In the noncontrast enhanced CT, the lesion presents as a soft tissue density mass with expansion of the bone. The bony cortex is usually intact. The adjacent soft tissues and cerebral parenchyma show no infiltration or edema. The post contrast scan reveals homogenous enhancement of the mass.

Female↗

Origin of syphilis.

Explore the source record for details and available documents.

History, 15th Century↗

Highly efficient and versatile synthesis of libraries of constrained beta-strand mimetics.

The general approach of using a bicyclic template to produce inhibitors of the protease superfamily of enzymes has been investigated. The Diels Alder cycloaddition reaction on solid support has been found to be highly efficient for the synthesis of libraries of compounds that mimic the beta-strand secondary structure of proteins. Several potent and selective inhibitors of proteases have been discovered.

Bridged Bicyclo Compounds, Heterocyclic↗

PATSy: a distributed multimedia approach to client assessment skills training.

This paper describes the development of an interactive distributed multimedia system (PATSy). When completed, it will serve as a repository of brain-injured clients and their test data for use by speech and language therapy students and researchers. In education, PATSy will be a resource which is flexible enough to accommodate various teaching pedagogies as well as support student learning in clinical assessment and diagnosis of various disorders.

Clinical Competence↗

A modality-specific mapping impairment: spoken versus written production.

A 29 year-old dysphasic woman (AF) presented with superior ability in written over spoken sentences. In contrast, her comprehension showed the reverse trend. Cognitive neuropsychological investigations revealed that her double dissociation was more apparent than real. AF's superior auditory comprehension was attributed to suspected dyslexic factors impeding written comprehension. However, an account of a strong dissociation between her written and spoken production was less obvious. The evidence suggested AF suffered from a procedural mapping deficit which had a disproportionate effect on spoken production. AF's performance challenge current models of lexical access which consider syntactic knowledge to be amodal. An alternative account is considered within Caramazza's (1997) Independent Network model of lexical access.

Adult↗

Apolipoprotein E genotype and Alzheimer's disease in Hong Kong elderly Chinese.

We studied the apolipoprotein E (apoE) allele frequencies in 65 Chinese patients with late-onset Alzheimer's disease (AD) and 82 age- and sex-matched controls. The apoE epsilon 4 allele frequency was significantly higher in the AD group than in the control group (0.169 versus, p < 0.01). There were five homozygotes for epsilon 4 in the AD group but none among the controls. The odds ratio for AD was 1.6 for epsilon 4 heterozygotes. The age at onset was lower in the presence of the epsilon 4 allele and higher with the epsilon 2 allele, although neither of these differences reached statistical significance. The association between apoE alleles and AD previously reported in Caucasian populations was also present in this reports of lower prevalence of AD compared with the prevalence of multi-infarct dementia.

Aged↗

Absorption of fluorescein given under the upper lid.

BACKGROUND: The need for a more efficacious approach to administer topical ocular medications prompted the authors to consider applying conventional eye drops under the upper lid rather than beneath the lower lid. Preliminary observations on patients with glaucoma using a beta-blocker beneath the upper lid suggested a drop in intraocular pressure into the normal range in some previously refractory patients being treated with the same medications. To test this clinical observation, the authors observed if there were any physiologic differences in topical fluorescein absorption into the anterior chamber when given beneath the upper lid versus the lower lid. METHODS: A 5-microliters drop of fluorescein solution was placed under the upper-lid fornix of one eye and under the lower-lid fornix of the other eye in human volunteers, and absorption into the anterior chamber was measured at hourly intervals, for a total of 3 hours. RESULTS: Hotelling T2 multivariate analysis for all 3 hours demonstrates that upper-lid administration of fluorescein results in significantly higher absorption of fluorescein into the anterior chamber than does lower-lid administration (P = 0.0088; for hours 2 and 3, the statistical differences is even more dramatic: P < 0.0044). CONCLUSION: Using conventional eye drops beneath the upper lid, the authors observed increased absorption of fluorescein into the anterior chamber when compared with lower-lid administration. Profuse tearing, especially by younger subjects, significantly and rapidly diminished anterior chamber absorption of fluorescein. It is reasonable to consider further clinical studies to test this new approach to drug delivery.

Absorption↗

Single lung transplantation. Alternative indications and technique.

Twenty-two patients have undergone 23 single lung transplants between March 1980 and April 1990 at the University of Texas Health Science Center at San Antonio. The actuarial survival rate is 77.27% at 12 months and 72.73% at 24 months. There have been no instances of bronchial dehiscence or stenosis, even though 13 of the patients were on a program of preoperative prednisone, every patient had high-dose perioperative methylprednisolone, and omental wraps were not used on any bronchial anastomosis. Of particular interest is the fact that three patients had primary pulmonary hypertension, three had secondary pulmonary hypertension, and 10 patients had chronic obstructive pulmonary disease, due in five cases to an alpha 1-antitrypsin deficiency. Each of these entities was previously thought to contraindicate single lung transplantation. Donor selection was based on an oxygen tension/inspired oxygen concentration ratio greater than 300, donor/recipient chest circumference within 3 inches, clear chest x-ray film, negative sputum Gram stain, and less than 6-hour estimated ischemic time. Harvest technique included donor prostaglandin E1 500 micrograms, topical slush, and pulmonoplegia with cold Euro-Collins solution. The heart and lung were separated in situ rather than the heart lung block being removed. A telescoping bronchial anastomosis was performed with 4-0 Prolene (not absorbable) sutures. We conclude that single lung transplantation has evolved into a simple operation, necessitating meticulous preoperative and postoperative care, which can be performed on a wide spectrum of critically ill patients with an acceptable mortality rate.

Adult↗

Portal vein opacification during ERCP in patients with pancreatitis.

We report two cases of portal vein visualization during ERCP in patients with pancreatitis, one from inadvertent cannulation of the superior mesenteric vein, and in the other, through a preexisting fistula. Prompt recognition of this potentially significant event will obviate confusion and unnecessary prolongation of the procedure.

Catheterization↗

Water-suppression MRI: role in the evaluation of osseous lesions.

The efficacy of chemical shift based water-suppression MRI in the evaluation of bone marrow lesions has not been previously reported. T1-weighted images without and with water suppression were compared in five patients with 16 lesions. There was a significant improvement in the contrast-to-noise ratio (from 4.32 to 5.95, P < 0.01) and contrast ratio (from 1.71 to 5.69, P < 0.004) with water suppression. Water suppression may be useful clinically by increasing the conspicuity of bone marrow lesions.

Adult↗