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Biomedical subjects

D Kempler

Publications and source records attributed to D Kempler.

At least 19 recordsLinked to original sources

Temporoparietal cortex in aphasia. Evidence from positron emission tomography.

Forty-four aphasic patients were examined with (F18)-fluorodeoxyglucose positron emission tomography in a resting state to determine whether consistent glucose metabolic abnormalities were present. Ninety-seven percent of subjects showed metabolic abnormalities in the angular gyrus, 89% in the supramarginal gyrus, and 87% in the lateral and transverse superior temporal gyrus. Pearson product moment correlations were calculated between regional metabolic measures and performance on the Western Aphasia Battery. No significant correlations were found between the Western Aphasia Battery scores and right hemisphere metabolic measures. Most left hemisphere regions correlated with more than one score from the Western Aphasia Battery. Temporal but not frontal regions had significant correlations to the comprehension score. The left temporoparietal region was consistently affected in these subjects, suggesting that common features in the aphasias were caused by left temporoparietal dysfunction, while behavioral differences resulted from (1) the extent of temporoparietal changes, and (2) dysfunction elsewhere in the brain, particularly the left frontal and subcortical areas.

Adult

Naming consistency in Alzheimer's disease.

Although lexical semantic deficits are postulated to play a prominent role in the anomia of Alzheimer's disease, it is unclear whether the primary disturbance is one of lexical access or one of lexical semantic loss. Response consistency on a naming task is one means of evaluating the underlying source of naming impairment. Access dysfunction usually implies variable word-finding difficulty, while a theory of lexical loss predicts that many word names would be consistently unavailable. Nineteen Alzheimer's disease patients were administered a visual confrontation naming task (the Boston Naming Test) on two occasions 6 months apart. Eighty percent of errors occurred consistently at both times; only 20% of errors occurred on only one occasion. Response consistency occurred significantly more often than expected under the assumption of no response consistency. Findings support the hypothesis that anomia in Alzheimer's disease is in part due to a loss of lexical semantic information.

Aged

Slowly progressive aphasia: three cases with language, memory, CT and PET data.

Three cases of slowly progressive speech and language disturbance were studied at various points post onset (three, five and 15 years respectively). Language, neuropsychological and brain imaging (computer tomography and positron emission tomography) evaluations were completed on all three patients. The data suggest that the syndrome of "progressive aphasia": 1) does not involve a uniform symptom complex; 2) does not necessarily develop into a full blown dementia syndrome; 3) varies greatly in rate of progression from case to case; 4) is associated with normal brain structure (on computer tomography); and 5) is associated with abnormal left temporal lobe metabolism as measured by fluorodeoxyglucose (FDG) positron emission tomography (PET). One patient had histological findings consistent with Alzheimer's disease at necropsy.

Aged

Cerebral glucose metabolism in Wernicke's, Broca's, and conduction aphasia.

Cerebral glucose metabolism was evaluated in patients with either Wernicke's (N = 7), Broca's (N = 11), or conduction (N = 10) aphasia using 18F-2-fluoro-2-deoxy-D-glucose with positron emission tomography. The three aphasic syndromes differed in the degree of left-to-right frontal metabolic asymmetry, with Broca's aphasia showing severe asymmetry and Wernicke's aphasia mild-to-moderate metabolic asymmetry, while patients with conduction aphasia were metabolically symmetric. On the other hand, the three syndromes showed the same degree of metabolic decline in the left temporal region. The parietal region appeared to separate conduction aphasia from both Broca's and Wernicke's aphasias. Common aphasic features in the three syndromes appear to be due to common changes in the temporal region, while unique features were associated with frontal and parietal metabolic differences.

Aphasia

Antimicrobial activity of calcium hydroxide liners on Streptococcus sanguis and S. mutans.

The antimicrobial activity of 10 calcium hydroxide liners on Streptococcus sanguis and S. mutans was studied. One hundred plates of tryticose soy agar-sheep red blood cells (10%), each with four distinct 3 mm diameter wells, were divided into two groups of 50. One group was inoculated with S. sanguis and the second group with S. mutans. A 4 mg liner was placed in each of three wells; the fourth well was left empty as a control. Plates were incubated at 37 degrees C and observed at 24 hours, 48 hours, and 7 days. All liners inhibited growth of both organisms. The inhibitory zones for S. mutans were larger than inhibitory zones for S. sanguis for all tested liners. Life Fast Set material had significantly less inhibitory effect on S. mutans. VLC Dycal, Life, and Life Fast Set materials had significantly less inhibitory effect on S. sanguis at p = 0.05.

Bacterial Infections

Technical note: antimicrobial action of glass-ionomer lining cement on S. sanguis and S. mutans.

There are a number of glass-ionomer lining cements available to the profession. It is generally agreed that the glass-ionomer cements demonstrate reasonably good biocompatibility. The purpose of this study was to evaluate the antimicrobial activity of six glass-ionomer cements on S. sanguis and S. mutans. Forty-eight plates of TSA-SRBC (10%), each with 3.0-mm-diam. wells, were divided into two groups (1 and 2) of 24 each. Group 1 was inoculated with S. sanguis (10558) and Group 2 with S. mutans (6715-13 w.t.). Each well was filled with 4.0 mg of one of the following liners: Glassic (A), Shofu lining cement (B), GC lining cement (C), Ever Bond (D), Gingiva Seal (E), and Ketac Bond (F); the empty wells served as control. Plates were incubated under microaerophilic conditions at 37 degrees C, and checked daily over seven days for inhibition zones. Average inhibition zones (mm) at 7 days were as follows: Group 1-1A = 10.00, 1B = 7.83, 1C = 18.50, 1D = 13.00, 1E = 8.67, and 1F = 9.33; Group 2-2A = 3.08, 2B = 10.25, 2C = 12.75, 2D = 15.58, 2E = 8.83, and 2F = 3.20. All control wells were 0.0 GC liner and Ever Bond showed significantly greater overall inhibition of microbial growth than did other tested liners (p less than 0.5). A one-way ANOVA and SNK test showed that all tested liners were significantly more toxic toward S. sanguis than toward S. mutans (p less than 0.05).

Dental Cavity Lining

Disconnection and cerebral metabolism. The case of conduction aphasia.

Ten patients with conduction aphasia were studied with computed tomography and 18-F-fluorodeoxyglucose positron emission tomography to examine glucose metabolism. Computed tomographic results identified a postrolandic structural locus for conduction aphasia. All patients demonstrated resting glucose hypometabolism throughout the parietal and temporal regions, and half of the patients also demonstrated reduced metabolic rates in the posterior, inferior, frontal (Broca's) regions. These data suggest that disconnection between posterior and anterior language areas may not be the best anatomical explanation for conduction aphasia.

Adult

Subcortical structures in aphasia. An analysis based on (F-18)-fluorodeoxyglucose, positron emission tomography, and computed tomography.

Subcortical structural damage that includes the anterior and posterior internal capsule, caudate, thalamus, lenticular nuclei, and insula has been shown to cause aphasias. A critical question that has not been resolved is whether the role of these structures on behavior is a direct one or whether it is indirect through the cortex. We have used pathway analysis to evaluate computed tomography, glucose metabolic, and language data from 47 aphasic patients to answer this question. For fluency (from the Western Aphasia Battery), subcortical structural damage had direct and indirect (through frontal lobe) effects on the behavior. For a comprehension task (sequential commands), subcortical damage had no direct effect and only a slight indirect effect through the temporal lobe. Thus, both direct and indirect effects of subcortical damage can be demonstrated for specific behavioral measures.

Adult

Xeroradiography in root fracture diagnosis.

Root fracture is a clinical problem that often is difficult to diagnose. The purpose of this study was to compare diagnostic value of conventional radiographic and xeroradiographic images of experimentally fractured teeth. Forty-five extracted human single-rooted teeth were used. The roots of the teeth were coated with wax to simulate periodontal ligament and invested in acrylic to the cementoenamel junction. An access cavity was prepared and para-post, size 4 to 12 mm, was placed into the root canal. Each tooth with post was placed on the load cell table of an Instron testing machine. The Instron continuously recorded load on a moving graph paper. The load was increased until the tooth fractured. Determination of fracture was made by the sound of a sharp "crack" and by a sudden release of load on the post, as seen on the Instron recording graph. After fracture, conventional radiograph and xeroradiograph were obtained for each tooth by use of the paralleling technique. The x-ray beam angle, film distance, and tooth placement were held constant in both techniques by use of a Rinn instrument. All films were evaluated by use of light from a masked viewbox, while all of the xeroradiographs were viewed in reflected light. A magnifying glass was used to aid in the examination process. The samples were examined and categorized for root fracture by the examiners with the use of the following scores: 0 = unacceptably poor, 1 = poor but diagnostic, 2 = adequate for diagnostic information, and 3 = optimal for diagnostic information.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Stress Analysis

Mesiodistal root fracture. Three case reports.

Vertical root fractures present a complex diagnostic problem. Three cases of vertical root fractures are presented. In the first case, there was a mesiodistal vertical fracture with an almost intact tooth structure. In the second case, there was a mesiodistal vertical fracture with an extensive amalgam restoration and improper root canal treatment. The third case showed extensive root caries with proper root canal therapy. All of the cases resulted in periodontal defects with subsequent loss of the tooth. Diagnosis was obtained with the use of clinical, fiberoptic, and disclosing solution examinations. Histologic examination revealed pulpal canals devoid of vital tissue and filled with necrotic material, debris, neutrophils, and bacterial colonies.

Adult

A comparison between xeroradiography and conventional radiography in the diagnosis of endodontic lesions.

Detection of periapical bone pathosis is an important part of the diagnostic process in dentistry. Xeroradiographs and E-speed films were taken to evaluate and to compare the diagnostic value for the radiographic interpretation of periapical lesions. Thirty-four patients undergoing endodontic treatment were chosen. Simultaneous exposures of the radiographic film and the xeroradiographic plates were made. The samples were viewed and categorized by the examiners using the following scores: 0 = unacceptably poor, 1 = poor but diagnostic, 2 = adequate for diagnostic information, and 3 = optimal for diagnostic information. A paired sample t test was performed on the result of the evaluation by the two examiners, and both showed that there were no significant difference at p less than 0.05 between xeroradiography and conventional radiography. A two-sample t test was performed on the means of the two examiner's evaluation, and there was no significant difference at p less than 0.05 between the means.

Alveolar Process

Proverb and idiom comprehension in Alzheimer disease.

Twenty-nine patients diagnosed with Probable Alzheimer Disease were administered tests of word, familiar phrases (idioms and proverbs), and novel phrase comprehension. From the early stage of the disease, patients performed worse at understanding familiar phrases than single words or novel phrases. The results uphold common observations that AD patients have difficulty interpreting abstract meanings. Cognitive variables responsible for poor idiom/proverb comprehension and the clinical implications of this new protocol are discussed.

Aged

Comprehension of familiar phrases by left- but not by right-hemisphere damaged patients.

Single words, familiar phrases (idioms and speech formulas), and novel sentences (matched to the familiar phrases in length, frequency, and structure) were selected for a picture-matching auditory comprehension task and administered to left- and right-brain damaged (LBD, RBD) subjects. The groups did not differ in single word comprehension. A 2 x 2 ANOVA revealed opposite patterns on the two other tasks, with LBD subjects performing worse on novel than familiar phrases, and RBD subject impaired on familiar phrase but not on novel sentence comprehension. The role of grammatical/referential vs. holistic/inferential meaning in left and right hemisphere function is discussed.

Aged

Human blood pressure and pulse rate response to racemic epinephrine retraction cord.

1. The pulse rate of patients after application of racemic epinephrine-impregnated retraction cords depends more on the level of anxiety and stress than on the level of the epinephrine. 2. Blood pressure is elevated by placement of racemic epinephrine-impregnated retraction cords upon an exposed vascular bed or lacerated tissue. 3. Four percent racemic epinephrine-impregnated retraction cords cause less elevation of blood pressure than 8% racemic epinephrine cords. 4. Although the elevations in blood pressure from 8% cord occur within a narrow range, this range may be hazardous to cardiac patients. Therefore, 4% racemic epinephrine cord should be used. 5. A desirable amount of tissue retraction is produced by 4% racemic epinephrine cord. 6. Dry cords do not provide adequate retraction of tissue and are contraindicated for tissue-retraction purposes.

Adult

Temporary restorative materials: properties and uses.

Various materials used for temporary restorations are reviewed, with reference to their chemical and physical properties. Research and standard specifications should be instituted in order to standardize and improve the many products now available to the profession. Knowledge of the materials and their properties will enable the dentist to arrive at correct selection of the material for each case, thus promoting more successful clinical procedures.

Acetates

Rationalization of electric pulp-testing methods.

A new electric pulp-testing system, the Testark, was developed in order to assess the potential of a different way of testing pulp sensitivity, thus making this electric pulp test more dependable than the conventional electric pulp-testing method. A study was conducted to evaluate the potential of the Testark system in comparison with a commercially available pulp tester. This pilot study consisted of application of three different desensitizing agents (sodium fluoride, test product. 'A', and test product 'B') to the cervical areas of hypersensitive teeth. The results were recorded with both the Testark and the conventional pulp tester simultaneously, and the sodium fluoride and test product 'B' proved to yield a beneficial effect by desensitizing the teeth after a single application. The level of desensitization with these agents was higher than the level obtained with the test product 'A' paste, which was utilized daily for 14 days. The results obtained with the conventional pulp tester differed by way of interpretation from those obtained with the Testark system. The Testark system proved to be easy to use and highly accurate in the data readings because of its high resolution. The Testark systemwas found to be more dependable than the commerical pulp tester, since it reduced the subjective errors which are inevitable when a commerical pulp tester is used. The Testark system is being developed further, and more studies are being conducted at the present time, in order to assess the full potential of the instrument.

Adult