PubMed Health⌕ Search

Biomedical subjects

E Gregory

Publications and source records attributed to E Gregory.

17 recordsLinked to original sources
PubMed1992

Pathway from the zona incerta to the superior colliculus in the rat.

In order to test the proposal that the zona incerta contributes to the generation of orienting movements, we examined the synaptic relationships between the incertotectal pathway and the cells of origin of the predorsal bundle. The predorsal bundle cells give rise to the major premotor pathway from the superior colliculus to the brainstem gaze centers. First, cytochrome oxidase histochemistry, gamma-aminobutyric acid (GABA), and glutamic acid decarboxylase (GAD) immunocytochemistry, and the axonal transport of markers were used to define the borders of a ventral subdivision of the zona incerta. This subdivision projects topographically to the same sublamina of the intermediate grey layer of the superior colliculus that contains the vast majority of the predorsal bundle cells. Experiments in which incertotectal cells were labeled by both retrograde transport and immunocytochemistry showed that this pathway is GABAergic. Retrograde and anterograde experiments also showed that this pathway is reciprocated by a pathway from the intermediate grey layer of the superior colliculus to the same ventral subdivision of the zona incerta. Finally, experiments combining axonal transport and electron microscopic methods showed that the incertotectal pathway is the source of a monosynaptic GABAergic input to the cells of origin of the predorsal bundle. The ventral subdivision of the zona incerta is contrasted with a second source of GABAergic input to the predorsal bundle cells, the substantia nigra pars reticulata.

Afferent Pathways↗
PubMed1988

Care and sterilization of endourologic instruments.

All endourologic instruments must be handled properly if they are to continue to function properly. Care must be taken in washing and sterilizing of this equipment, as not all endoscopic equipment can endure all methods, and people who are working with these instruments must be taught the proper care and sterilization methods of each. For example, fiberoptic telescopes and light cables must never be autoclaved; ethylene oxide is the method of choice. Disinfectant is an alternative. Loops, sheaths, high-frequency cables, resectoscopes, and working elements should be sterilized by ethylene oxide. Loops and high-frequency cables should not be soaked in a disinfectant, but other instruments may be soaked. All instruments should be dried before sterilization. Too much emphasis cannot be placed on the importance of proper storage of these very fragile fiberoptic instruments. With proper care and sterilization, these instruments will need fewer repairs and function properly for a longer time.

Disposable Equipment↗
PubMed1975

Male hamster preference for odors of female hamster vaginal discharges: studies of experiential and hormonal determinants.

Male hamsters approach sources of odors from female hamster vaginal discharges and spend significantly more time around these odor sources than around control locations in the test box. This preference for female hamster vaginal odors appears in sexually inexperienced as well as experienced males, even in individuals isolated from females since the time of weaning. Castration significantly reduces the sex odor preference, and treatment with testosterone propionate partially restores it.

Animals↗
PubMed1971

Fluctuations in antibiotic resistances of gram-negative rods in one hospital, 1961-70, with comment on kanamycin-neomycin relationships.

Records of the percentages of various types of gram-negative rods resistant to six antibiotics are presented for the years 1961 to 1969 with additional notes on 1970. Gross amounts of each antibiotic used in each of the years are also depicted. Resistance-factor transference does not seem to be an important factor but levels of antibiotic usage do seem to affect the percentages of resistant strains found. In the case of kanamycin, extensive use of neomycin appears to have produced much cross-resistance. Free use of polymyxins does not seem to increase resistant percentages.

Ampicillin↗
PubMedDate not supplied

Variation in the lung inhomogeneity correction factor with beam energy. Clinical implications.

In order to determine the magnitude of the dosimetry error introduced by failing to correct for increased transmission through lung tissue in treating thoracic malignancies, measurements in a phantom were taken using different field sizes, inhomogeneity thicknesses and photon qualities. The results indicate that the error introduced by neglecting the inhomogeneity correction is greatest at lower photon energies, smaller field sizes and greater thickness of inhomogeneity. Correction factors to account for the lung inhomogeneity were obtained from phantom measurements and were compared with those calculated using the tissue-air ratio and Batho-Young algorithms; correlation coefficients describing the relationship between measured and calculated values exceeded 0.995. The calculated values tended to overestimate the correction factor and differed most from the measured correction factors at lower energies, smaller field sizes, and greater inhomogeneity thicknesses. The importance of these results in clinical radiation therapy is discussed.

Cobalt Radioisotopes↗