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Biomedical subjects

S Brandt

Publications and source records attributed to S Brandt.

At least 55 records · Page 3Linked to original sources
PubMed1993

Implementation of a quiet hour: effect on noise levels and infant sleep states.

It is necessary to decrease environmental stimuli in order to provide developmentally supportive care to the very low birthweight (VLBW) infant, thereby enhancing the sleep/wake cycle and possibly physiologic stability. The purpose of this study was to determine if it was possible to decrease the noise level in the Developmental Unit, and promote sleep states in infants on the unit. After determining control noise levels and infant state, the last hour of each shift was designated a Quiet Hour. During this time, noise levels were monitored in the room in five locations. Infant sleep states were also noted. The results indicate that noise levels decreased significantly on two of the three shifts. Fewer infants were crying during the Quiet Hour than the control period (2.4 vs 14.3 percent), and more were in deep or light sleep (84.5 vs 33.9 percent). This study demonstrates that noise levels in Developmental Units can be significantly decreased, and that the decreased noise levels positively impact infant state. By enhancing sleep states, nurses can enhance the long term developmental outcome of the VLBW infant. However, the reduction of noise is highly dependent on the collaborative efforts of all health care providers within the unit.

Clinical Nursing Research↗
PubMed1992

Fibrosarcoma cells transduced with the IL-6 gene exhibited reduced tumorigenicity, increased immunogenicity, and decreased metastatic potential.

Murine fibrosarcoma cell lines transduced with retroviral vectors containing the murine interleukin 6 (IL-6) gene constitutively secreted IL-6. When injected s.c. into normal mice these IL-6-secreting tumors exhibited reduced tumorigenicity. This reduced tumorigenicity was not seen in nude or irradiated mice, implicating a T-cell-dependent, radiosensitive host response activated by the cytokine. Subcutaneous IL-6-secreting tumor did not retard the growth of distant deposits of wild-type tumor in the same host. However, animals rejecting IL-6-secreting tumors exhibited resistance to later challenge with wild-type tumor. When injected i.v. in an experimental metastasis model the IL-6-secreting tumors failed to or were extremely inefficient in giving rise to pulmonary nodules; this was observed in both normal and immunoincompetent mice, implicating a second, nonimmune mechanism affecting the growth of the tumor modified to secrete IL-6.

Animals↗
PubMed1992

Isoliquiritigenin, a strong nod gene- and glyceollin resistance-inducing flavonoid from soybean root exudate.

Isoflavonoid signal molecules from soybean (Glycine max (L.) Merr.) seed and root exudate induce the transcription of nodulation (nod) genes in Bradyrhizobium japonicum. In this study, a new compound with symbiotic activity was isolated from soybean root exudate. The isolated 2',4',4-trihydroxychalcone (isoliquiritigenin) is characterized by its strong inducing activity for the nod genes of B. japonicum. These genes are already induced at concentrations 1 order of magnitude below those required of the previously described isoflavonoid inducers genistein and daidzein. Isoliquiritigenin is also a potent inducer of glyceollin resistance in B. japonicum, which renders this bacterium insensitive to potentially bactericidal concentrations of glyceollin, the phytoalexin of G. max. No chemotactic effect of isoliquiritigenin was observed. The highly efficient induction of nod genes and glyceollin resistance by isoliquiritigenin suggests the ecological significance of this compound, although it is not a major flavonoid constituent of the soybean root exudate in quantitative terms.

Benzopyrans↗
PubMed1992

The Yankton Model Program.

Changes in medical education towards a student-centered, problem-based learning, with continuity care experience in ambulatory settings have been recommended. The University of South Dakota School of Medicine has developed such an educational model for third year medical students named the Yankton Model Program and is herein described.

Curriculum↗
PubMed1990

Alpha 2-adrenergic binding sites in the medulla oblongata of tree shrews demonstrated by in vitro autoradiography: species related differences in comparison to the rat.

Alpha 2-adrenergic binding sites in the medulla oblongata of tree shrews and rats were detected and quantified by in vitro-autoradiography with the alpha 2-antagonist 3H-rauwolscine (3H-RAUW). The autoradiographic pattern of the radioligand binding in the tree shrew medulla oblongata resembles that which has been described by others for the human myelencephalon. This pattern coincides well with the occurrence of catecholaminergic structures detected by immunocytochemistry with antibodies against phenylethanolamine-N-methyltransferase and tyrosine hydroxylase. In contrast to the rat, where only the nucleus tractus solitarii and the nucleus dorsalis nervi vagi were labeled, five discrete nuclei specifically bound 3H-RAUW in tree shrews. The highest number of binding sites was detected in the nucleus dorsalis nervi vagi (nX; Bmax: 333 fmoles/mg) and the nucleus tractus solitarii (NTS; 311 fmoles/mg), followed by the nucleus nervi hypoglossi (nXII; 297 fmoles/mg), the nucleus reticularis parvocellularis (FRS; 230 fmoles/mg), and the area of the catecholamine cell groups A1 and C1 (area C1; 202 fmoles/mg). Maximal binding in the two labeled nuclei of the rat was 158 fmoles/mg. The discrete nuclei of the two species also showed different affinities for 3H-RAUW with Kd ranging from 0.17 to 0.83 nM in tree shrews and 1.80 to 1.95 nM in rats. Competition experiments revealed that the radioligand bound specifically to alpha 2-binding sites. In the tree shrew, nX, nXII and the area C1, also have a relatively high affinity for the alpha 1-antagonist prazosin which is a quality of the adrenoceptor subtype alpha 2B. Furthermore, in the area C1, 3H-RAUW binding was inhibited by the dopamine antagonist haloperidol. There are thus species related as well as regional differences with respect to the number, the affinity, and the pharmacological properties of alpha 2-binding sites in the medulla oblongata. In tree shrews, alpha 2-adrenoceptors can be autoradiographically quantified in regions which are not labeled in the rat, although former data predicted the existence of such receptors, e.g., in the area of the adrenaline cell group C1.

Animals↗
PubMed1990

Diazepam inhibits stimulating effect of cooling preoptic area on antibody production.

To clarify the mechanism of the stimulating effect of fever on the primary antibody response, rats were immunized with sheep erythrocytes, and a fever-like response was induced by cooling the preoptic area for five days. Diazepam, 0.5 mg/kg, given daily during the cooling time, did not affect the normal antibody response of the control animals nor did it prevent the rise in body temperature elicited by cooling the preoptic area but it did, nevertheless, strongly reduce the stimulating effect of this procedure on antibody production. A smaller reduction of this effect was also seen in adrenalectomized rats in which a physiological and stable plasma level of corticosterone was maintained. Because diazepam suppresses some sympathetic and endocrine responses to stress, these data suggest that the effect of cooling the preoptic area on the primary antibody response, and, by inference, that of fever, is to a large extent mediated by the adrenal and other stress response or responses to the cold stimulus. The results do not, however, exclude the possibility of an additional, direct effect of the elevated body temperature on immunocompetent cells.

Adrenalectomy↗
PubMed1989

Frequency analysis of accommodation: single sinusoids.

We present an experimental frequency analysis of a neurological control system, the accommodation system, using single sinusoids. Also, by means of continual experimental calibration full coverage of one subject's dynamic range, we demonstrate an AC nonlinearity saturation, which probably lies in the motor-response portion of the system; in contrast to the switching-mode nonlinearity, which probably lies in the sensory-processing portion. We offer our findings as a basis for further models. In addition, our results can be compared with studies using multiple sinusoids and transients to document how the different aspects of the accommodation system are realized given their different input conditions.

Accommodation, Ocular↗
PubMed1987

The effect of a fever-like response on the secondary antibody response of the rat.

Since fever appears to modulate the primary humoral immune response, a fever-like response was induced in 18 rats by cooling their preoptic areas during the first five days after re-immunization with sheep erythrocytes. The titre of antibodies in these rats was the same as that in 17 control animals, indicating that the febrile response does not influence the magnitude of the secondary antibody response. It is suggested that only those fevers evolving in the early phase of a primary, natural infection may modulate the magnitude of the humoral immune response to the pathogen.

Animals↗
PubMed1984

The effect of hypothalamic temperature on the immune response in the rat.

To clarify the role of febrile temperatures on the immune system, rats were immunized with sheep erythrocytes and their core temperature was then changed by continuously cooling or heating the preoptic area for five days. Core temperatures of up to 2 degrees C above or below normal were associated with a high titre of antibodies against sheep erythrocytes, whereas larger displacements of core temperature, as well as normal temperature, were associated with a low titre. These results are at variance with the idea that the production of antibodies is proportional to body temperature. It is suggested that the immunostimulation elicited by heating and cooling the preoptic area, and by inference that the immunostimulation associated with fever, could be due to factors other than the change in body temperature.

Animals↗