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Biomedical subjects

D Morse

Publications and source records attributed to D Morse.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Properties and cellular localization of a luciferin binding protein in the bioluminescence reaction of Gonyaulax polyedra.

A luciferin binding protein LBP involved in the bioluminescence reaction of Gonyaulax polyedra was purified and used for antibody production. Luciferin bound to LBP is fluorescent and can be used as a marker in living cells, allowing the localization of LBP in cortical organelles to be visualized. In cell sections, the same peripheral localization was observed using anti-LBP and immunofluorescence microscopy. The amount of LBP is ten-fold greater from cells from in night phase compared to those from in day phase, as determined both by immunoblots of cell extracts, and in vivo fluorescence. These changes correlate with the circadian changes in bioluminescence of living cells.

Animals↗
PubMedDate not supplied

Evidence of neuronal degeneration in C57B1/6 mice infected with the LP-BM5 leukemia retrovirus mixture.

Mice infected with LP-BM5 develop a severe immunodeficiency accompanied by learning and memory deficits, gliosis, and neurotransmitter abnormalities. The neurochemical alterations are consistent with elevated excitotoxin levels, suggesting that infected mice may incur neuronal damage. Although the number of neocortical neurons was unchanged in mice 12 wk after LP-BM5 infection, the expression of cytoskeletal proteins declined, particularly in the frontal and parietal cortex as indicated by MAP2, NF-200, and synaptophysin immunoreactivity. In contrast, the number of striatal neurons decreased 19%. The remaining neurons were smaller, with fewer synaptic boutons, and showed decreased synaptophysin and NF-200, immunoreactivity. Immunoblots of cortex and striatum confirmed decreases in MAP2, NF-200 and synaptophysin expression. Finally, although NCAM expression decreased in the striatum, it increased in the cortex. These results indicate that LP-BM5-infected mice sustain significant neuronal damage, which may contribute to their behavioral deficits. Moreover, the increase in cortical NCAM expression suggests active synaptic remodeling to compensate for the persistent excitotoxic environment in these mice, whereas striatal neurons degenerate. These concurrent degenerative and compensatory processes may also occur in the brains of patients with AIDS dementia complex (ADC), who suffer extensive degeneration of the basal ganglia and cerebral cortex.

AIDS Dementia Complex↗
PubMedDate not supplied

The polypeptide components of scintillons, the bioluminescence organelles of the dinoflagellate Gonyaulax polyedra.

Scintillons, the bioluminescence organelles of Gonyaulax polyedra, were purified by isopycnic density gradient centrifugation until only low levels of contaminating chloroplasts and mitochondria were detected by fluorescence and electron microscopy. Purified scintillons catalyzed the luminescent reaction with kinetics identical to those observed during the bioluminescence flash in vivo. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the organelles appeared to contain only two proteins. These proteins were identified as luciferase (135 kilodaltons) and luciferin-binding protein (75 kilodaltons) based on their size and their known functions in the bioluminescence reaction in vitro. The staining of luciferin-binding protein by Coomassie blue was 2.4 +/- 0.3 (n = 19) times greater than the luciferase, suggesting that there are four binding protein monomers for every luciferase monomer. A model is proposed for the close packing of the two proteins inside the scintillons.

Animals↗
PubMedDate not supplied

Active bacterial core surveillance of the emerging infections program network.

Active Bacterial Core surveillance (ABCs) is a collaboration between the Centers for Disease Control and Prevention and several state health departments and universities participating in the Emerging Infections Program Network. ABCs conducts population-based active surveillance, collects isolates, and performs studies of invasive disease caused by Streptococcus pneumoniae, group A and group B Streptococcus, Neisseria meningitidis, and Haemophilus influenzae for a population of 17 to 30 million. These pathogens caused an estimated 97,000 invasive cases, resulting in 10,000 deaths in the United States in 1998. Incidence rates of these pathogens are described. During 1998, 25% of invasive pneumococcal infections in ABCs areas were not susceptible to penicillin, and 13.3% were not susceptible to three classes of antibiotics. In 1998, early-onset group B streptococcal disease had declined by 65% over the previous 6 years. More information on ABCs is available at www.cdc.gov/ncidod/dbmd/abcs. ABCs specimens will soon be available to researchers through an archive.

Bacterial Infections↗
PubMedDate not supplied

Retrograde cardioplegia infusion during coronary bypass surgery. Early clinical experience.

Although aortic root cardioplegia infusion has been generally satisfactory, adequate myocardial protection in patients with critical coronary artery disease (CAD) cannot always be achieved by this route. We report our experience with our first 19 consecutive patients, all with exceptionally severe disease in whom the coronary sinus route was utilized for cardioplegia infusion. Eleven had unstable angina, and three had persistent chest pain requiring intensive antianginal therapy right up to time of surgery. Blood cardioplegia was infused via the coronary sinus using a Foley Catheter under a monitored pressure of 30 mmHg. Ischemic time was 83 +/- 27 minutes. Number of vessels bypassed was 4.9 +/- 0.9. Prebypass hemodynamic profile was compared to the profile at 15 and 75 minutes, and at 6, 12 and 24 hours after cessation of bypass, and revealed good preservation of myocardial function: Cardiac index, stroke volume index and pulmonary capillary wedge pressure remained unchanged, systemic vascular resistance decreased by 30%, while changes of lesser magnitude were observed in systemic and pulmonary blood pressure. There was no death and one perioperative myocardial infarction. Myocardial temperature was monitored by needle thermisters and demonstrated homogeneous myocardial cooling in spite of the severity of CAD. Thus, preservation of cardiac function even in patients with critical and extensive CAD can be achieved by coronary sinus infusion of cardioplegia.

Adult↗