High-energy and thermal-neutron imaging and modeling with an amorphous silicon flat-panel detector.

The Los Alamos Neutron Science Center (LANSCE) operates two spallation neutron sources dedicated to research in materials science, condensed-matter physics, and fundamental and applied nuclear physics. Prior to 1995, all thermal neutron radiography at Los Alamos was done on a beam port attached to the Omega West reactor, a small 8MW research reactor used primarily for radioisotope production and prompt and delayed neutron activation analysis. After the closure of this facility, two largely independent radiography development efforts were begun at LANSCE using moderated cold and thermal neutrons from the Target-1 source and high-energy neutrons from the Target-4 source. Investigations with cold and thermal neutrons employed a neutron converter and film, a scintillation screen and CCD camera system, and a new high-resolution amorphous silicon (a-Si) flat-panel detector system. Recent work with high-energy neutrons (En > 1 MeV) has involved storage-phosphor image plates. Some comparison high-energy images were obtained with both image plates and the a-Si panel and showed equivalent image quality for approximately equal exposure times.     

Elder abuse--a family experience.

Abuse happens every day to elderly and disabled individuals either through ignorance or design. Protecting your patient or loved one requires you to be suspicious of everyone who has access to the patient, even other family members. It is the most difficult and demanding task you will ever undertake. Our story is a long and emotional one, If you wish to read an account of our experiences, please visit my Web site at www.iannarino.us/elderabuse.     

Type III collagen mutations cause fragile cerebral arteries.

Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.     

Role of spinal opioid receptors in the antinociceptive interactions between intrathecal morphine and bupivacaine.

In studies on the clinical management of pain, a combination of morphine and bupivacaine is more effective than either of them alone in producing analgesia. The present study was designed to examine the effect of bupivacaine on morphine-induced antinociception as measured by the tail-flick test in the rat. To understand the basis of this interaction, the effect of bupivacaine on the binding of opioid ligands to their spinal opioid receptors in the rat also was investigated. Intrathecal administration of 5, 20, or 50 micrograms bupivacaine significantly potentiated the antinociception produced by intrathecal administration of 10 micrograms morphine. There was more than a 10-fold increase in the area under the curve (AUC0-60 min) for morphine-induced antinociception in the presence of bupivacaine. At higher doses of morphine (20 micrograms), bupivacaine was not very effective, increased AUC0-60 min for antinociception by only about 25%, and in fact significantly decreased the total duration of morphine-induced antinociception. Radioreceptor assays done with rat spinal cord membrane preparations revealed that bupivacaine (0.1-10 nM) inhibited the binding of specific ligands to mu-receptors but increased the binding to delta- and kappa-receptors. The authors conclude that the facilitation of morphine-induced antinociception by bupivacaine may be associated with a conformational change in the spinal opioid receptors induced by bupivacaine. Although increasing the binding of morphine to kappa-opioid receptors is the most prominent effect, the binding of opioid ligands to all spinal receptors is inhibited at high doses of bupivacaine.     

Patellamide E: a new cyclic peptide from the ascidian Lissoclinum patella.

A new cyclic peptide, patellamide E [1], was isolated from the ascidian Lissoclinum patella collected at Pulau Salu, Singapore. Its structure was determined by nmr spectroscopy, and its absolute configuration by acid hydrolysis and analysis of the derivatized constituent amino acids by hplc. Patellamide E was mildly cytotoxic against human colon tumor cells in vitro.     

A retrospective study of nosocomial pneumonia at a long-term care facility.

BACKGROUND: Results of a passive surveillance system (pneumonia confirmed by x-ray examination) suggested that in 1989 a total of 187 cases of nosocomial pneumonia had occurred at the Canandaigua Veterans Administration Medical Center among 250 long-term care patients. METHODS: A retrospective study was undertaken to validate cases and to enumerate risk factors. A chart review showed that 136 of 187 cases (72%) met predetermined criteria for nosocomial pneumonia. RESULTS: Three nursing units characterized as at high risk had a pneumonia rate of 1.90 per 1000 patient days, as compared with a rate of 0.70 cases per 1000 patient days on the two other units. There were no differences in age, mean white blood cell count, or clinical symptoms between high- and average-risk patients. Two thirds of all patients had a history of chronic aspiration. High-risk patients were more likely to be confined to bed, to have a debilitating neurologic disease, and to require tube feedings. Twenty percent of patients on high-risk units died of nosocomial pneumonia or with nosocomial pneumonia as a contributory factor. CONCLUSIONS: Facility-associated pneumonia is an important cause of morbidity and mortality in long-term care facilities.