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Biomedical subjects

S Swanson

Publications and source records attributed to S Swanson.

46 records · Page 3Linked to original sources
PubMed1982

Serotonin N-acetyltransferase and its regulation by pineal substances.

The regulation of activity of serotonin N-acetyltransferase (NAT) in pineal glands of various mammalian hierarchies may be species-specific, mediated by different mechanisms and brought about by interactions with dissimilar receptor sites. In addition to norepinephrine, serotonin and gamma-aminobutyric acid (GABA) seem to modulate NAT activity. Furthermore, preliminary studies provide evidence for the existence in pineal gland of a thermo-stable proteinaceous substance (NIS) which inactivates NAT but not other enzymes involved in the synthesis of melatonin. Inactivation of NAT by NIS is blocked by addition of 0.5 mM acetyl coenzyme A, but not coenzyme A, 0.1 M NaF or 4 mM beta-mercaptoethanol. In addition, protein dephosphorylation and disulfide exchange mechanisms are not involved in this NIS-mediated inactivation of NAT. In rat brain, the inactivating substance was found only in the pineal gland and was undetectable in other tissues. We postulate that the collective interaction among norepinephrine, serotonin, GABA, acetyl coenzyme A, NIS and NAT may regulate the synthesis of melatonin in the pineal gland.

Acetyl Coenzyme A↗
PubMed1979

Reproducibility of ejection fraction and ventricular volume by gated radionuclide angiography after myocardial infarction.

To validate the repeated use of radionuclide equilibrium angiography for determining left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes (EDV and ESV), 25 patients were studied on an hourly basis an average of 9.1 days after acute myocardial infarction. Data were processed with a semi-automatic computer program which develops an averaged-volume curve from an assigned LV region-of-interest. LV EDV and ESV were derived from a previously described method which correlates well with contrast angiography (r = 0.977, y = 0.0255x - 0.121). Comparison between initial and subsequent equilibrium EF and between initial and subsequent volumes showed excellent correlation. Excluding three anginal episodes, the EF variation between studies averaged 0.03 +/- 0.02.

Acute Disease↗
PubMedDate not supplied

Synthesis and influenza virus sialidase inhibitory activity of analogues of 4-Guanidino-Neu5Ac2en (Zanamivir) modified in the glycerol side-chain.

Analogues of 4-Guanidino-Neu5Ac2en (Zanamivir) have been prepared containing carbamate substituents at the 7-hydroxy position. (4S,5R,6R)-5-Acetylamino-6-[1R-[(6-aminohexyl)carbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro-4H-pyran-2carboxylic acid and (4S,5R,6R)-5-Acetylamino-6-[1R-[heptylcarbamoyloxy]-2R,3-dihydroxypropyl]-4-guanidino-5,6-dihydro4H-pyran2-carboxylic acid were the two analogues possessing activity comparable to Zanamivir, showing potent inhibition of influenza virus sialidases and good antiviral activity in vitro.

Antiviral Agents↗
PubMedDate not supplied

Computed tomography of emphysematous gastritis.

Emphysematous gastritis is a rare entity and only 31 cases have been reported. We describe a case that was diagnosed by CT. To our knowledge the CT appearance of this serious disease has not been described previously.

Adult↗
PubMedDate not supplied

CT appearance of cervical lipoblastoma.

We describe a case of lipoblastoma causing respiratory symptoms in an infant, where CT was useful in establishing the diagnosis and demonstrating the extent of involvement so that complete surgical resection could be planned.

Female↗
PubMedDate not supplied

Functional magnetic resonance imaging in partial epilepsy.

Functional magnetic resonance imaging (FMRI) detects signal changes in brain that accompany regional changes in neuronal activity. In normal human brain, FMRI shows changes in signal in the postcentral gyrus or superior temporal gyrus that correlate with voluntary motor activity or language processing, respectively. The model used to explain the changes in signal linked temporally with cerebral activity is a reduction in cerebral capillary deoxyhemoglobin concentration due to the increased blood flow that accompanies neuronal activity in the cerebrum. FMRI has been used in normal subjects but not extensively in patients. To determine the feasibility of using FMRI to map cerebral functions in patients with partial epilepsy syndromes, we performed a pilot study, using FMRI to identify signal changes in motor and language areas in response to tasks that activate those areas. Signal changes in epilepsy patients approximated those observed in volunteers. We conclude that FMRI can be developed as a method for functional cerebral mapping in partial epilepsies.

Adult↗
PubMedDate not supplied

Malignant pleural effusions after resection of pulmonary adenocarcinoma.

OBJECTIVE: To evaluate the clinicopathologic features of malignant pleural effusions secondary to pulmonary adenocarcinoma in patients who have undergone surgical resection of the primary tumor. STUDY DESIGN: Clinical, pathologic and cytologic material from 19 patients who developed malignant pleural effusions after resection of pulmonary adenocarcinoma was reviewed. RESULTS: Malignant effusions developed only in patients with either lymph node or pleural involvement by neoplasm. Time to development of the effusion after resection and overall survival correlated with histologic findings. Malignant effusions in patients who survived > 24 months were secondary to another primary tumor (either breast or a new pulmonary carcinoma). Malignant effusions developed significantly sooner after resection (mean 5.0 +/- 2.0 months, median 5) in patients with lymph nodal metastases than in those with pleural involvement by neoplasm (mean 11.2 +/- 2.5 months, median 12) (Student's t test P = .01, Mann-Whitney U test .04). Nevertheless, survival after resection for patients with lymph node involvement (mean 9.0 +/- 3.6 months, median 8) and those with pleural involvement (mean 12.3 +/- 2.5 months, median 12) was not significantly different. CONCLUSION: Malignant effusions developing in patients more than two years following resection of a pulmonary adenocarcinoma are likely to be secondary to another primary neoplasm. Lymph node and pleural involvement at the time of resection are risk factors for the development of a malignant effusion. Patients with lymph node involvement develop malignant effusions sooner than those with pleural involvement, but the overall survival is not significantly different.

Adenocarcinoma↗
PubMedDate not supplied

Functional MR of frontal lobe activation: comparison with Wada language results.

PURPOSE: Our purpose was to determine the utility of functional MR imaging in conjunction with a word-generation paradigm in the assessment of language lateralization. METHODS: Functional MR imaging and Wada testing for language lateralization was performed in patients with complex partial seizures during the performance of word-generation tasks. A language lateralization quotient was calculated from the number of activated pixels in the right and left hemispheres. A language laterality score was derived from the Wada results as the percentage of correct responses during right internal carotid artery injection minus the percentage of correct responses during left internal carotid injection. A correlation coefficient between the functional MR imaging results and the Wada language laterality scores was calculated. RESULTS: In 13 patients, hemispheric dominance based on Wada testing was confirmed by functional MR imaging during silent word generation. The Wada laterality scores varied from 100 to -100 and the functional MR imaging scores varied from 100 to -10. The language lateralization scores determined by functional MR imaging correlated significantly with the language lateralization scores derived from Wada testing. CONCLUSION: Functional MR imaging performed during word generation is an accurate method for lateralizing language function in patients with complex partial epilepsy.

Adult↗