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Biomedical subjects

L Goetz

Publications and source records attributed to L Goetz.

12 recordsLinked to original sources
PubMed2000

Direct measurement of sound velocity in various specimens of breast tissue.

RATIONALE AND OBJECTIVES: Previous studies using ultrasound CT or clinical amplitude/velocity reconstruction imaging ultrasound may indicate that cancers differ from normal breast tissue by increased sound velocity. However, only limited experience with direct measurements of sound velocity exists. This study aimed to investigate sound velocity measured directly in a variety of breast specimens. METHODS: Sound velocity was measured directly by forceps in fresh breast specimens chosen to contain one type of tissue only. Eighty specimens (31 cancers, 18 benign changes of glandular/fibrous tissue, 22 fatty tissues, 5 fibroadenomas, 2 compound tissues, 1 phylloides tumor, and 1 inflammation) were analyzed. RESULTS: Ultrasound velocities in carcinoma, benign changes, fibroadenoma, inflammation, and the phylloides tumor were very similar, with almost complete overlap. In contrary, the ultrasound velocity of fatty tissue was significantly lower. Compound tissues containing fat had an intermediate sound velocity. CONCLUSIONS: Sound velocity may add complementary information to echogenicity (B-scan). Because fat lobules exhibit low ultrasound velocity and carcinomas do not, a locally exact combination of ultrasound velocity information and reflexivity information should allow improved breast cancer detection by ultrasound.

Breast Diseases↗
PubMed1996

Impact of prophylactic ganciclovir on bronchoalveolar lavage lymphocyte numbers and phenotypes in murine cytomegalovirus-induced reactivation of Toxoplasma pneumonia.

In a mouse model of cytomegalovirus (CMV)-induced immunosuppression, murine CMV (MCMV) infection results in reactivation of Toxoplasma pneumonia, and prophylactic but not delayed administration of ganciclovir attenuates the severity of this pneumonia. We now report that the protection observed with ganciclovir is associated with blunting of the alterations in bronchoalveolar lavage (BAL) lymphocyte numbers and phenotypes observed in untreated mice. Specifically, prophylactic ganciclovir prevents the usual drop in BAL CD4+ lymphocytes observed in the first week after MCMV injection--that is, the period of MCMV-associated immunosuppression. Furthermore, prophylactic ganciclovir markedly blunts the usual rise in BAL T lymphocytes (CD8+ > CD4+) seen later during the peak of reactivated Toxoplasma pneumonia. These findings suggest that prophylactic ganciclovir can protect animals from virus-associated opportunistic pneumonia by attenuating virus-induced changes in BAL lymphocytes and the attendant suppression of lung immunity.

Animals↗
PubMed1995

Use of integrated, general education, and community settings as primary contexts for skill instruction for students with severe, multiple disabilities.

Four students with severe, multiple disabilities learned to use four to five new skills at critical moments within age-appropriate activities. Instruction was provided only at moments critical to the continuation of the activities when natural cues and consequences delineated the need for the target behaviors. This method of intervention was combined with a more traditional package of antecedent prompt-fade procedures and, in a few instances, time delay. The purpose of the study was to analyze the effects of instruction given only at natural critical moments on the acquisition of basic sensory, motor, social, and communication behaviors. A multiple baseline design across skills within separate activities for four participants was employed. Fifteen of 17 skills were acquired to criterion. In addition, "learning to learn" effects occurred within each activity as instruction of new target behaviors was introduced. The outcomes are important for the participant population because they document the effect of integrated educational models for teaching the most basic skills. Discussion of the motivation provided by activity routines in general education and community settings, as well as interpretation of data when participants have the most severe disabilities, is presented.

Behavior Therapy↗
PubMed1995

Individual social skills training and co-worker training for supported employees with dual sensory impairment. Two case examples.

Two case studies examined the efficacy of two social enhancement procedures--individual social skills training (SST) and co-worker intervention for two employees with dual sensory impairment who were working in competitive employment settings but who were socially isolated from contact with their nondisabled co-workers. A variety of measures, including direct behavioral observations and social validation ratings, examined social interaction and the formation of social networks in the workplace. Results showed that the number and duration of social interactions improved with each of the social enhancement programs. Social validation data and anecdotal reports indicated that the employees with disabilities became more socially competent, interactive, and included in the social network of the workplace. Interestingly, SST followed by co-worker training resulted in greater increases in social responding as compared to co-worker training followed by SST.

Adult↗
PubMed1984

Health and environmental implications of trace metals released from coal-fired power plants: an assessment study of the situation in the European Community.

In the European Community (EC) the anticipated increased use of coal for power production will lead to an increase in the release of trace metals into the environment. This release seems unlikely to cause toxicological effects through the food chain, but there may be a possibility of a direct impact on man through inhalation. There are, however, many areas of uncertainty which need to be clarified by further research before a definitive assessment can be made.

Coal↗
PubMed1981

Environmental biochemistry of current environmental levels of heavy metals: preparation of radiotracers with very high specific radioactivity for metallobiochemical experiments on laboratory animals.

Environmental toxicology research on dose-response relationships of heavy metals requires experiments on laboratory animals exposed to "low doses" of trace elements which should reflect "present or actual environmental levels" characteristic of polluted environments. Unfortunately no criteria exist to establish the "low doses" to which laboratory animals must be exposed, in practice the choice of the level used is made in an almost arbitrary manner. In order to define the "present environmental levels" of heavy metals which should be administered to laboratory animals an approach is suggested, based upon knowledge of the concentrations of trace elements in the diet, air and food as well as the fractions absorbed. Today daily intakes of trace elements by man are of the order of few micrograms or nanograms thus requiring the use of extremely sensitive analytical techniques to determine the very low amounts of heavy metals in tissues and cellular components. In these fields of research the use of radiotracers with very high specific radioactivity appears particularly advantageous but requires considerable care during their preparation and use. The first part of this paper deals with a definition of the ranges of concentrations of trace elements which should be used for metabolic studies on laboratory animals when they are exposed via different routes such as ingestion, inhalation in injection; the second part describes the production of radiotracers with very high specific radioactivity by proton activation in the cyclotron and by neutron irradiation in the nuclear reactor. Their use to label present levels of heavy metals under conditions adapted for biochemical purposes, as well as the preparation of different metal-labelled chemical species is also reported. Particular attention is directed to quality control of the radiotracer solutions which are administered to the animals including those of radioactivity concentrations, radioisotopic purity, radiochemical purity, carrier content and chemical impurities.

Animals↗