Biomedical subjects

Douglas Green

Publications and source records attributed to Douglas Green.

5 recordsLinked to original sources

PubMed2005

Incidental findings computed tomography of the thorax.

Numerous findings incidental to the stated indication for obtaining a computed tomogram (CT) of the chest are encountered. While some findings are life threatening (eg, pulmonary embolism), others are clearly benign (pulmonary hamartoma, vertebral hemangioma). This article discusses management issues related to the detection of unexpected findings in different compartments of the thorax. In the future, more detailed outcome data will be available to better guide medical decision-making.

Cardiovascular Diseases↗

PubMed2004

GSK3-mediated BCL-3 phosphorylation modulates its degradation and its oncogenicity.

The oncoprotein BCL-3 is a nuclear transcription factor that activates NF-kappaB target genes through formation of heterocomplexes with p50 or p52. BCL-3 is phosphorylated in vivo, but specific BCL-3 kinases have not been identified so far. In this report, we show that BCL-3 is a substrate for the protein kinase GSK3 and that GSK3-mediated BCL-3 phosphorylation, which is inhibited by Akt activation, targets its degradation through the proteasome pathway. This phosphorylation modulates its association with HDAC1, -3, and -6 and attenuates its oncogenicity by selectively controlling the expression of a subset of newly identified target genes such as SLPI and Cxcl1. Our results therefore suggest that constitutive BCL-3 phosphorylation by GSK3 regulates BCL-3 turnover and transcriptional activity.

Animals↗

PubMed2004

Prospective studies of Bartonella of rodents. Part I. Demographic and temporal patterns in population dynamics.

The temporal dynamics of Bartonella infections in a rodent community were described by repeatedly capturing and sampling individual animals. Among six rodent species, from which bartonellae were isolated, cotton rats (Sigmodon hispidus) accounted for > 98% of the bacteremic animals. All cotton rats captured four or more times were Bartonella-culture positive at least once. The lowest monthly prevalence of Bartonella in cotton rats was in June (49%) and the highest was in October (95%). Prevalence of Bartonella infection increased to > 90% among juvenile and subadult rats before declining to < 40% among the largest-oldest individuals. Bacteremia levels ranged between 40 and 4.0 x 10(6) colony forming units (CFU) per 1 mL of blood. Male cotton rats had significantly higher CFUs than females (p = 0.006). The median of Bartonella bacteremia decreased monotonically by age group among cotton rats. Although Bartonella infections were highly prevalent among cotton rats, only 8.5% of rats had reactive antibodies at titers of > or = 1:32 and none had antibodies titers of > 1:256.

Age Factors↗

PubMed2004

Prospective studies of Bartonella of rodents. Part II. Diverse infections in a single rodent community.

The genetic diversity of Bartonella species within a small mammal community and in individual cotton rats (Sigmodon hispidus) was examined by trapping, capturing, sampling, and releasing of marked animals over a 17-month interval. Based on sequence analyses of the Bartonella gltA gene, amplicons separated into four genogroups (A, B, C, and Pin) containing 11 variants. Although the prevalence of bacteremia due to different genogroups/variants of Bartonella was temporally variable, variants of genogroup A predominated during each sampling period. Multiple gltA variants were often (20.5% of individuals) isolated from a single cotton rat blood sample; a maximum of five variants was recovered from an individual during its sampling history. Among 92 cotton rats bacteremic at two or more sampling dates, 34 rats retained a single genetic variant, alone or in mixed infection, throughout their sampling history. The temporal course of individual infections was complex as the succession of gltA variants was variable and detectable bacteremia was often intermittent. No antibodies (titer of >1:8) were detected to homologous strains of Bartonella recovered from individual cotton rats during their sampling history. The temporal course of Bartonella infections could result from a single, persistent, and potentially multi-genogroup/variant infection, during which variants differentially dominate the detectable bacteremia.

Animals↗

PubMed2003

CTA and MRA: visualization without catheterization.

The ideal modality for vascular imaging would be noninvasive and inexpensive. A volumetric acquisition would permit visualization of vessels from arbitrary angles. High contrast between the vessel lumen and background tissue would be coupled with excellent spatial resolution allowing accurate depiction of small vessels. Characterization of the constituent components of the vessel wall would be possible. High temporal resolution would both freeze the motion of fast moving vessels and show the direction and speed of blood flow. Finally, the modality would expose the patient to a minimal amount of ionizing radiation or potentially toxic contrast agents. Diagnostic conventional catheter angiography offers unsurpassed spatial and temporal resolution. However, catheter angiography is an interventional procedure, exposes the patient to both ionizing radiation and iodinated contrast, and does not depict the vessel wall. Additionally, view angles are chosen before the administration of contrast and may not demonstrate certain lesions. These limitations have driven the development of both computed tomography angiography (CTA) and magnetic resonance angiography (MRA). Both of these modalities rapidly acquire volumetric data sets, which can then be evaluated slice by slice or by more advanced volumetric rendering techniques. CTA and MRA are minimally invasive and less costly than angiography. While CTA and MRA cannot compete with the spatial or temporal resolution of conventional angiography, present technology has proven clinical efficacy in a wide range of applications. The principles behind CTA and MRA and their comparative strengths and weaknesses will be discussed. The different volumetric rendering techniques will be reviewed. Finally, recent advances that will likely further improve these modalities will be summarized.

Angiography↗