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Richard Green

Publications and source records attributed to Richard Green.

At least 19 recordsLinked to original sources
PubMed2026

High-grade astrocytoma with piloid features: a clinical and genomic analysis of prognostic factors using a large cohort.

BACKGROUND: High-grade astrocytoma with piloid features (HGAP) is a recently defined tumor type that is not well-understood. Prognostic factors of clinical outcomes are not well-established. METHODS: Methylation profiling was performed on tumor samples, many at the National Cancer Institute (NCI) Laboratory of Pathology, and others from publicly available sources. Methylation classifier scores of ≥ 0.90 to the HGAP class on the NCI-Bethesda classifier version 3 were included. Clinical features were collected from the medical record. Survival analyses were performed using the Kaplan-Meier and Cox-proportional hazards methods. RESULTS: The cohort comprised 421 patients. There were high rates of ATRX alteration (62%), CDKN2A/B homozygous loss (78%) and MGMT promoter methylation (53%). MAPK alterations were identified in 74% of evaluable samples. The median age was 46 years, and posterior fossa location was predominant (52%). The median overall survival (OS) was 88 months. Older age (p = 0.01) and the presence of an ATRX alteration (p = 0.04) were found to be negative prognostic factors. The presence of cystic features on magnetic resonance imaging (MRI) was found to be favorably prognostic (p = 0.01). Factors that were not significantly associated with prognosis included histologic high-grade features, CDKN2A/B homozygous deletion, MGMT promoter methylation, extent of resection, and presence of NF1 syndrome. CONCLUSIONS: This large cohort establishes relative frequencies of several important markers. Additionally, older age, the presence of an ATRX alteration, and cystic features on MRI were found to be prognostic. Our work may aid in optimizing treatment regimens for patients with this tumor type.

ATRX alteration↗
PubMed2007

The CAPTURE registry: results of carotid stenting with embolic protection in the post approval setting.

BACKGROUND: Pivotal study data examining carotid stenting with embolic protection as a less invasive alternative to endarterectomy for high surgical risk patients have been acquired under controlled conditions with highly selected physicians and hospitals. This report examines outcomes of carotid stenting post-approval after diffusion of this technology to a broader cross-section of physicians and hospitals. METHODS: The Carotid Acculink/Accunet Post-Approval Trial to Uncover Unanticipated or Rare Events (CAPTURE) is a prospective, multi-center registry to assess two important aspects of the post-IDE experience: the safety of carotid stenting by physicians with varying levels of experience as a measure of the adequacy of physician training, and the identification of rare/unexpected device-related complications. The primary endpoint was a composite of death, any stroke, or myocardial infarction within 30 days post-procedure. RESULTS: 3,500 patients were enrolled by 353 physicians at 144 sites. The 30-day primary endpoint event rate was 6.3% (95% CI: 5.5-7.1%) and did not differ among the three operator experience levels (5.3%, 6.0%, and 7.4%; P = 0.31) from most to least experienced, respectively. There were no differences in outcomes among physician specialties when adjusted for case mix. There were no unanticipated device related adverse events. CONCLUSIONS: The results of the CAPTURE study compare favorably to those achieved in the predicate pivotal investigations, and suggest that the post-approval transfer of this new therapy to the community practice setting via carotid stent training programs is effective in preparing physicians with varying experience levels and specialty training backgrounds.

Aged↗
PubMed2006

Cytokine and antibody subclass responses in the intestinal lymph of sheep during repeated experimental infections with the nematode parasite Trichostrongylus colubriformis.

The expression of interleukin (IL)-4, IL-5, IL-10, IL-13, TNF-alpha and IFN-gamma genes, and parasite-specific IgM, IgG1, IgG2, IgA and total IgE levels, were monitored daily in intestinal lymph of sheep infected repeatedly with the nematode parasite Trichostrongylus colubriformis. Host genotype had a significant influence on IL-13 gene activity, with resistant-line (R) sheep consistently expressing higher levels of mRNA than susceptible-line (S) sheep. Mean gene expression of IL-13, IL-4 and IFN-gamma did not differ significantly between the first and second nematode challenge. Field-primed R and S as well as field-primed R and naïve S sheep had lower mean gene expression of IL-5 and IL-10, respectively, during the second when compared to primary challenge. Genes for IL-13 and IL-5 were transiently and strongly up-regulated after nematode infection, particularly in animals with previous exposure to nematodes. Genes for TNF-alpha and IFN-gamma were also transiently up-regulated, but to a lesser extent and more typically after primary challenge. Naïve sheep of both genotypes produced relatively little antibody response after primary challenge. A second nematode challenge resulted in large increases in the lymphatic levels of all antibody sub-classes which were significant for adult antigen-specific IgA and larval antigen-specific IgG1. In naïve S line sheep, the larval-specific IgA and IgG2 response appeared delayed when compared to the R line animals. Field-primed R and S line sheep had relatively high lymphatic IgG1 levels prior to experimental infection and these did not change significantly afterwards. These results demonstrate that during nematode infections, the intestinal micro-environment of sheep is transiently skewed towards Th2 cytokine dominance, although IFN-gamma gene expression continues. This response is accompanied by increases of nematode-specific IgG1, IgA, IgG2 and IgM, as well as of total IgE in lymph plasma.

Animals↗
PubMed2006

Estrogen treatment effects on cognition, memory and mood in male-to-female transsexuals.

Gonadal hormones, particularly estrogens, have been suggested to influence memory and cognitive tasks that show sex differences. Previously, we reported that male-to-female (M-F) transsexuals undergoing estrogen treatment for sex re-assignment scored higher on verbal Paired Associate Learning (PAL) than a transsexual control group awaiting estrogen treatment. The present study used a more robust design to examine further associations between estrogen and cognition. We assessed additional aspects of memory, including visual, spatial, object and location memory, other cognitive abilities that show reliable sex differences, including verbal and visual-spatial abilities, and mood variables that could mediate associations between estrogen and cognition. In addition to comparing groups of individuals on and off estrogen, we used two repeated measures designs (AB and BA). The AB group was tested prior to hormone treatment and then again after treatment had begun; the BA group was tested while on estrogen treatment and then again when hormones had been withdrawn prior to surgery. Few changes in memory or cognition were observed, and changes that were observed were not consistent across study designs. The lack of significant effects did not relate to mood changes or to the sexual orientation of participants. These findings suggest that estrogen treatment associated with sex change for M-F transsexuals has little or no influence on sex-typed aspects of cognition or memory.

Adult↗
PubMed2006

Acute appendicitis in a patient with undiagnosed pheochromocytoma.

Pheochromocytoma is a rare catecholamine-producing tumor that can cause severe hypertension and other systemic disturbances. A clinical challenge arises when a patient with a previously undiagnosed and untreated pheochromocytoma presents with a surgical emergency. We describe a patient presenting with acute appendicitis in whom surgery was cancelled because of suspected pheochromocytoma. The possibility of mortality associated with surgery in a patient with an undiagnosed pheochromocytoma outweighed the risk of nonoperative management for appendicitis. This case resulted in a nonoperative resolution of appendicitis and an unremarkable recovery once appropriate hypertension treatment was administered.

Adrenal Gland Neoplasms↗
PubMed2006

Dolasetron versus ondansetron as single-agent prophylaxis for patients at increased risk for postoperative nausea and vomiting: a prospective, double-blind, randomized trial.

This study identified 100 ambulatory surgery patients receiving general anesthesia who were at increased risk for postoperative nausea and vomiting (PONV) and randomly assigned them to receive single-agent prophylaxis (12.5 mg of dolasetron or 4 mg of ondansetron) 15 to 30 minutes before the end of surgery. Data were collected in the postanesthesia care unit, and patients completed a questionnaire 24 hours after surgery. No statistically significant difference existed between study groups in demographic features, history of PONV, history of motion sickness, or type and duration of surgery and anesthesia. No statistically significant difference existed in satisfaction with the medication used for PONV prophylaxis (dolasetron, 70.9 of 100 mm; ondansetron, 67.9 of 100 mm; p = 0.69). No statistically significant difference existed in satisfaction with the overall surgical experience (dolasetron, 87.9 of 100 mm; ondansetron, 85.3 of 100 mm; p = 0.36). Costminimization strategies should be considered without fear of substandard care or increased patient dissatisfaction.

Adolescent↗
PubMed2005

Screening primary care patients for hereditary hemochromatosis with transferrin saturation and serum ferritin level: systematic review for the American College of Physicians.

BACKGROUND: Therapeutic phlebotomy for hereditary hemochromatosis is relatively safe and presumably efficacious when offered before cirrhosis develops, so screening primary care patients is of substantial interest. PURPOSE: To conduct a systematic review of the evidence on 1) the prevalence of the disease in primary care, 2) the risk for morbid or fatal complications for untreated patients, 3) the diagnostic usefulness of transferrin saturation and serum ferritin level in identifying early disease, 4) the efficacy of early treatment, and 5) whether the benefits of screening outweigh the risks. DATA SOURCES: MEDLINE search from 1966 through April 2004, complemented by reference review of identified original studies and review articles published in English. STUDY SELECTION: PubMed Clinical Queries filters search of prognosis, diagnosis, etiology, or treatment were used depending on the question. Two authors reviewed all titles and abstracts. DATA EXTRACTION: Two investigators independently reviewed extracted data. DATA SYNTHESIS: The prevalence of hereditary hemochromatosis was 1 in 169 patients to 1 in 556 patients (n = 3 studies). Uncontrolled, prospective studies of genetic homozygous patients did not consistently identify a link to overt hereditary hemochromatosis. A serum ferritin level less than 1000 microg/L was predictive of absence of cirrhosis. Six studies demonstrated reduced survival in patients with cirrhosis. Diagnostic studies varied with respect to case definition. No blinded, independent comparisons of screening tests with the gold standard (biopsy or results of quantitative phlebotomy) or randomized, controlled trials of phlebotomy were identified. Cost-effectiveness analysis was limited by lack of prospective data on the natural history of the disease. LIMITATIONS: Varied case definition and lack of prospective cohort studies or randomized trials. CONCLUSIONS: The available evidence does not demonstrate that benefits outweigh the risks and costs of screening for hemochromatosis.

Adult↗
PubMed2005

Renal and iliac artery stenting by interventional cardiologists and vascular surgeons: the Foundation to Advance Medical Education (FAME) initiative.

The American College of Cardiology, in concert with the Society for Coronary Angiography and Interventions and the Society for Vascular Surgery, planned and implemented an initiative to teach stenting of renal and iliac arteries to their peers in practice. Supported by the Foundation to advance medical Education (FAME), the initiative involved 25 preceptees and 6 preceptors and included a didactic portion (a remote learning exercise), an animal practicum, a procedural simulation, and a preceptor/preceptee training segment, all of which was followed by evaluations by the participants. Assessments of the success of the initiative differed between preceptees, who were positive about the experience, and preceptors, who were more critical of the endeavor (with surgeons more critical than cardiologists). Technical problems, such as obtaining temporary licensure to practice medicine in another state, interfered with the hands-on experiences of several preceptees. Programs such as the FAME initiative will grow in importance as new technologies continue to be introduced into medical practice and the need to train physicians in practice in their use expands.

Animals↗
PubMed2004

Does the non-identity problem block a class of arguments against cloning?

One class of argument against cloning human beings in the contemporary literature focuses on the bad consequences that will befall the clone or "later-twin." In this paper I consider whether this line of argumentation can be blocked by invoking Parfit's non-identity problem. I canvass two general strategies for solving the non-identity problem: a consequentialist strategy and non-consequentialist, rights based strategy. I argue that while each general strategy offers a plausible solution to the non-identity problem as applied to the cases most frequently discussed in the non-identity problem literature, neither provides a reason for putting aside the non-identity problem when applied to cloning. I conclude (roughly) that the non-identity problem does serve to block this class of argument against cloning.

Cloning, Organism↗
PubMed2003

Should patients with challenging anatomy be offered endovascular aneurysm repair?

OBJECTIVES: Treatment of abdominal aortic aneurysm is controversial in patients at high physiologic risk for open repair and high anatomic risk for endovascular repair. We compared outcome in patients at high risk because of anatomy (short or angulated neck), severe occlusive disease, or bilateral iliac aneurysms (group A) with outcome in patients at low risk (group B). MATERIAL AND METHODS: Patients at high anatomic risk who underwent treatment between October 1998 and March 2002 with the Zenith endovascular graft (group A) were compared with patients at low anatomic risk enrolled in a prospective multicenter trial (group B). Variables compared included overall mortality, need for secondary interventions, development of endoleak, and change in aneurysm sac diameter. The chi(2) test, Student t test, and proportions analysis were used to assess the data. RESULTS: Data for 493 patients (group A, 141; group B, 352) were evaluated. Mean follow-up was 9 months (range, 1-24 months). Perioperative mortality was similar for groups A and B (0.7% vs 1%). Frequency of endoleak was higher in patients with high-risk anatomy (25% vs 11%), but not significantly so (P >.06). The rate of aneurysm shrinkage, even in the absence of endoleak, was slower in group A (P <.05). CONCLUSIONS: In physiologically challenged patients at higher anatomic risk for endovascular aneurysm repair, initial mortality rate is similar to that in patients at lower risk. Short-term technical results are acceptable. Decreased long-term survival (largely unrelated to the procedure), slightly higher frequency of endoleak, and a lower rate of sac shrinkage may temper enthusiasm for endovascular repair in this subgroup. Risks of repairing aneurysms in this patient population must be viewed in the context of expected results of intervention or medical observation.

Algorithms↗
PubMed2003

The "t" word.

Explore the source record for details and available documents.

Female↗
PubMed2003

Thrombus characterization with intravascular ultrasound: potential to predict successful thrombolysis.

PURPOSE: To define analysis methods using radiofrequency (RF) data from intravascular ultrasound (IVUS) to characterize thrombus so that the success or failure of thrombolysis can be predicted. METHODS: Experimentation was done in 2 phases: first, 40 clots created from platelet-rich (n=20) and platelet-poor (n=20) plasma were imaged with 20 and 30-MHz IVUS probes. The digitized RF signals were analyzed to determine the attenuation and slope of attenuation characteristics as a reference standard for the second part of the study. In this phase, 20 perfusion trials were performed with 10 platelet-rich and 10 platelet-poor samples in an in vitro arterial perfusion model; the composition of the samples was blinded during interrogation with IVUS. Alteplase (0.1 mg) was then infused directly into the thrombus for 1 hour; restoration of flow and amount of lysis were quantified. RESULTS: Significant differences were detected for the integrated attenuation value (p<0.001) between platelet-poor and platelet-rich clots interrogated with a 30-MHz probe, but no differences were noted using the 20-MHz catheter. However, both transducers were capable of differentiating platelet-rich and platelet-poor clots using a slope of attenuation analysis, which was successful in identifying all 20 (100%) of the blinded clots in the in vitro model. The speed and completeness of lysis were significantly higher (p<0.05) for platelet-rich (78%) than platelet-poor (21%) clots. CONCLUSIONS: IVUS preprocessed imaging is capable of differentiating various types of thrombus. This information can be used to predict the success or failure of pharmacological lysis techniques.

Equipment Design↗