Biomedical subjects

D Salina

Publications and source records attributed to D Salina.

8 recordsLinked to original sources

PubMed2001

Cytotoxic activity of moronic acid and identification of the new triterpene 3,4-seco-olean-18-ene-3,28-dioic acid from Phoradendron reichenbachianum.

The cytotoxic compound moronic acid (1) and the new tetracyclic triterpene 3,4-seco-olean-18-ene-3,28-dioic acid (2), were isolated from the aerial parts of the medicinal plant Phoradendron reichenbachianum (mistletoe, Loranthaceae) through a bioassay-guided fractionation. In addition, squalene, glycerol trilinoleate, morolic acid, betulonaldehyde, betulinaldehyde, alpha-germanicol, lupeol, beta-sitosterol and beta-sitosteril glucopyranoside, were identified in this plant species. The structures were elucidated on the basis of chemical and spectroscopic evidence.

Antineoplastic Agents, Phytogenic↗

PubMed2001

Nuclear envelope dynamics.

The nuclear envelope (NE) provides a semi permeable barrier between the nucleus and cytoplasm and plays a central role in the regulation of macromolecular trafficking between these two compartments. In addition to this transport function, the NE is a key determinant of interphase nuclear architecture. Defects in NE proteins such as A-type lamins and the inner nuclear membrane protein, emerin, result in several human diseases that include cardiac and skeletal myopathies as well as lipodystrophy. Certain disease-linked A-type lamin defects cause profound changes in nuclear organization such as loss of peripheral heterochromatin and redistribution of other nuclear envelope components. While clearly essential in maintenance of nuclear integrity, the NE is a highly dynamic organelle. In interphase it is constantly remodeled to accommodate nuclear growth. During mitosis it must be completely dispersed so that the condensed chromosomes may gain access to the mitotic spindle. Upon completion of mitosis, dispersed NE components are reutilized in the assembly of nuclei within each daughter cell. These complex NE rearrangements are under precise temporal and spatial control and involve interactions with microtubules, chromatin, and a variety of cell-cycle regulatory molecules.

Animals↗

PubMed1999

Sequential recruitment of NPC proteins to the nuclear periphery at the end of mitosis.

Nuclear pore complexes (NPCs) are extremely elaborate structures that mediate the bidirectional movement of macromolecules between the nucleus and cytoplasm. With a mass of about 125 MDa, NPCs are thought to be composed of 50 or more distinct protein subunits, each present in multiple copies. During mitosis in higher cells the nuclear envelope is disassembled and its components, including NPC subunits, are dispersed throughout the mitotic cytoplasm. At the end of mitosis, all of these components are reutilized. Using both conventional and digital confocal immunofluorescence microscopy we have been able to define a time course of post-mitotic assembly for a group of NPC components (CAN/Nup214, Nup153, POM121, p62 and Tpr) relative to the integral nuclear membrane protein LAP2 and the NPC membrane glycoprotein gp210. Nup153, a component of the nuclear basket, associates with chromatin towards the end of anaphase, in parallel with the inner nuclear membrane protein, LAP2. However, immunogold labeling suggests that the initial Nup153 chromatin association is membrane-independent. Assembly of the remaining proteins follows that of the nuclear membranes and occurs in the sequence POM121, p62, CAN/Nup214 and gp210/Tpr. Since p62 remains as a complex with three other NPC proteins (p58, 54, 45) during mitosis and CAN/Nup214 maintains a similar interaction with its partner, Nup84, the relative timing of assembly of these additional four proteins may also be inferred. These observations suggest that there is a sequential association of NPC proteins with chromosomes during nuclear envelope reformation and the recruitment of at least eight of these precedes that of gp210. These findings support a model in which it is POM121 rather than gp210 that defines initial membrane-associated NPC assembly intermediates.

Animals↗

PubMed1999

Function and assembly of nuclear pore complex proteins.

Nuclear pore complexes (NPCs) are extremely elaborate structures that mediate the bidirectional movement of macromolecules between the nucleus and cytoplasm. The current view of NPC organization features a massive symmetrical framework that is embedded in the double membranes of the nuclear envelope. It embraces a central channel of as yet ill-defined structure but which may accommodate particles with diameters up to 26 nm provided that they bear specific import/export signals. Attached to both faces of the central framework are peripheral structures, short cytoplasmic filaments, and a nuclear basket assembly, which interact with molecules transiting the NPC. The mechanisms of assembly and the nature of NPC structural intermediates are still poorly understood. However, mutagenesis and expression studies have revealed discrete sequences within certain NPC proteins that are necessary and sufficient for their appropriate targeting. In addition, some details are emerging from observations on cells undergoing mitosis where the nuclear envelope is disassembled and its components, including NPC subunits, are dispersed throughout the mitotic cytoplasm. At the end of mitosis, all of these components are reutilized to form nuclear envelopes in the two daughter cells. To date, it has been possible to define a time course of postmitotic assembly for a group of NPC components (CAN/Nup214, Nup153, POM121, p62 and Tpr) relative to the integral inner nuclear membrane protein LAP2 and the NPC membrane glycoprotein gp210. Nup153, a dynamic component of the nuclear basket, associates with chromatin towards the end of anaphase coincident with, although independent of, the inner nuclear membrane protein, LAP2. Assembly of the remaining proteins follows that of the nuclear membranes and occurs in the sequence POM121, p62, CAN/Nup214 and gp210/Tpr. Since p62 remains as a complex with three other NPC proteins (p58, p54, p45) during mitosis, and CAN/Nup214 maintains a similar interaction with its partner, Nup84, the relative timing of assembly of these additional four proteins may also be inferred. These observations suggest that there is a sequential association of NPC proteins with chromosomes during nuclear envelope reformation and the recruitment of at least eight of these precedes that of gp210. These findings support a model in which it is POM121 rather than gp210 that defines initial membrane-associated NPC assembly intermediates and which may therefore represent an essential component of the central framework of the NPC.

Animals↗

PubMed1997

A worksite smoking intervention: a 2 year assessment of groups, incentives and self-help.

Sixty-three companies in the Chicago area were recruited to participate in a worksite smoking cessation program. Participants in each worksite received a television program and newspaper supplement (part of a community-wide media campaign), and one of three conditions: (1) self-help manuals alone (M), (2) self-help manuals and incentives for 6 months (IM) or (3) maintenance manuals, incentives and cognitive-behavioral support groups for 6 months (GIM). Results at the 2 year assessment are examined using a random-effects regression model. In addition, various definitions of quit-rate commonly used in smoking cessation research are explored and the advantages of using a public health approach in the worksite are examined.

Humans↗

PubMed1994

A follow-up of a media-based, worksite smoking cessation program.

Described an examination of data collected 2 years following the onset of a media-based, worksite smoking cessation intervention. Thirty-eight companies in Chicago were randomly assigned to one of two experimental conditions. In the initial 3-week phase, all participants in both conditions received self-help manuals and were instructed to watch a 20-day televised series designed to accompany the manual. In addition, participants in the group (G) condition received six sessions emphasizing quitting techniques and social support. In the second phase, which continued for 12 months, employees in G participated in monthly peer-led support groups and received incentives, while participants in the nongroup (NG) condition received no further treatment. Twenty-four months after pretest, 30% of employees in G were abstinent compared to only 19.5% in NG. This study is one of the few experimentally controlled worksite smoking cessation interventions to demonstrate significant program differences 2 years following the initial intervention.

Employment↗

PubMed1994

Analysis of clustered data in community psychology: with an example from a worksite smoking cessation project.

Although it is common in community psychology research to have data at both the community, or cluster, and individual level, the analysis of such clustered data often presents difficulties for many researchers. Since the individuals within the cluster cannot be assumed to be independent, the use of many traditional statistical techniques that assumes independence of observations is problematic. Further, there is often interest in assessing the degree of dependence in the data resulting from the clustering of individuals within communities. In this paper, a random-effects regression model is described for analysis of clustered data. Unlike ordinary regression analysis of clustered data, random-effects regression models do not assume that each observation is independent, but do assume data within clusters are dependent to some degree. The degree of this dependency is estimated along with estimates of the usual model parameters, thus adjusting these effects for the dependency resulting from the clustering of the data. Models are described for both continuous and dichotomous outcome variables, and available statistical software for these models is discussed. An analysis of a data set where individuals are clustered within firms is used to illustrate features of random-effects regression analysis, relative to both individual-level analysis which ignores the clustering of the data, and cluster-level analysis which aggregates the individual data.

Cluster Analysis↗

PubMed1993

Prevalence of chronic fatigue syndrome-related symptoms among nurses.

Chronic Fatigue Syndrome is an illness that is characterized by debilitating fatigue and a group of other related symptoms. Few epidemiological studies have been conducted, and none have focused on a nursing population. The present study is the first to assess the prevalence of Chronic Fatigue Syndrome-related symptoms in a sample of nurses. Demographic characteristics, symptoms, and possible prevalence rates are presented and discussed. When using both narrow and more inclusive criteria to define this symptom complex, higher rates of this disorder were found than in previous epidemiological studies. The implications of these findings are discussed.

Adult↗