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Biomedical subjects

Michael J Hall

Publications and source records attributed to Michael J Hall.

12 recordsLinked to original sources
PubMed2006

Timing of adjuvant chemotherapy initiation after surgery for stage III colon cancer.

BACKGROUND: An important advance in medical oncology has been the use of adjuvant chemotherapy for lymph node-positive colon cancer. However, to the authors' knowledge, the effect of the interval between surgery and the initiation of chemotherapy on survival has not been investigated. METHODS: The authors analyzed predictors and outcomes of time intervals to treatment after surgery among patients older than 65 years who were diagnosed with stage III colon cancer between 1992 and 1999 using Surveillance, Epidemiology, and End Results (SEER)-Medicare data. Linear and logistic regression analyses were used to model predictors of delay, and Cox proportional hazards models were used to analyze the impact of treatment timing on survival. RESULTS: Among 4382 patients with colon cancer, 1122 patients (26%) began adjuvant chemotherapy within 1 month, 2391 patients (55%) began adjuvant chemotherapy in 1 to 2 months, 454 patients (10%) began adjuvant chemotherapy in 2 to 3 months, and 415 patients (9%) began adjuvant chemotherapy >/=3 months after surgery. Intervals of >/=3 months (delay) were associated with older age, increased comorbid conditions, well/moderately differentiated grade, and being unmarried. Colon cancer-specific mortality was associated with a delay in the initiation of chemotherapy (hazards ratio [HR], 1.48; 95% confidence interval [95% CI], 1.15-1.92), advanced age, increased comorbidity, poorly differentiated tumor grade, the presence of >/=4 positive lymph nodes, and undergoing surgery in a nonteaching hospital. All-cause mortality was associated with intervals >2 months between surgery and chemotherapy (2 to 3 months: HR, 1.41; 95% CI, 1.15-1.74; >/=3 months: HR, 1.62; 95% CI, 1.31-1.99) compared with <1 month. CONCLUSIONS: In the older population that was studied, only 9% of patients initiated adjuvant chemotherapy >3 months after the date of curative surgery. However, delay in initiation was associated with both cancer-specific and all-cause mortality. Determining whether these results were because of chemotherapy timing or other associated factors will require further study.

Age Factors↗
PubMed2006

Disparities in genetic testing: thinking outside the BRCA box.

The impact of predictive genetic testing on cancer care can be measured by the increased demand for and utilization of genetic services as well as in the progress made in reducing cancer risks in known mutation carriers. Nonetheless, differential access to and utilization of genetic counseling and cancer predisposition testing among underserved racial and ethnic minorities compared with the white population has led to growing health care disparities in clinical cancer genetics that are only beginning to be addressed. Furthermore, deficiencies in the utility of genetic testing in underserved populations as a result of limited testing experience and in the effectiveness of risk-reducing interventions compound access and knowledge-base disparities. The recent literature on racial/ethnic health care disparities is briefly reviewed, and is followed by a discussion of the current limitations of risk assessment and genetic testing outside of white populations. The importance of expanded testing in underserved populations is emphasized.

Genetic Predisposition to Disease↗
PubMed2006

PET modulated fluorescent sensing from the BF2 chelated azadipyrromethene platform.

A convergent building block synthesis has been applied to new off/on photoinduced electron transfer (PET) modulated fluorescent sensors which are based on a BF(2) chelated tetraarylazadipyrromethene platform and operate in the biomedically important red region of the visible spectrum. Incorporation of diethylamine and morpholine receptors facilitates off/on microenvironment polarity and pH sensing. Aqueous formulation and in vitro cellular imaging demonstrates their potential for intracellular sensing.

Alkenes↗
PubMed2005

Supramolecular photonic therapeutic agents.

A new approach to achieving selectivity for photodynamic therapy based upon the reversible off/on switching of the key therapeutic property (singlet oxygen generation) of a supramolecular photonic therapeutic agent (SPTA) in response to an external stimulus in the surrounding microenvironment is described. A series of SPTA analogues with pH responsive receptors of varying pKa are presented, in which the generation of singlet oxygen is shown to be dependent upon a proton source. For example, systems have been constructed such that the excited state energy of the photosensitizer can be decayed by a rapid photoinduced electron transfer (PET) mechanism, resulting in virtually no singlet oxygen being generated, but when the amine receptor is protonated the PET mechanism does not operate and singlet oxygen is produced. In vitro efficacy demonstrated that the SPTA derivatives can be activated within cells and one analogue is measured to have an EC50 value of 5.8 nM when assayed in the MRC5 cell line.

Benzofurans↗
PubMed2005

A modular synthesis of unsymmetrical tetraarylazadipyrromethenes.

[reaction: see text] A stepwise route to unsymmetrical tetraarylazadipyrromethenes by a condensation of 2,4-diaryl-5-nitroso-pyrroles with 2,4-diarylpyrroles is described. This modular building-block approach allows for the introduction of up to four different aryl substituents on the azadipyrromethene and is tolerant of a varied substituent set. An efficient synthesis of the 2,4-diarylpyrroles building blocks from 1,3-diaryl-4-nitro-butan-1-ones by nitro hydrolysis to a keto-aldehyde and subsequent ammonia condensation reaction has been achieved. The facile conversion of 2,4-diarylpyrroles into their alpha-nitroso analogues by their reaction with sodium nitrite generated the second building block required for the synthesis.

Journal Article↗
PubMed2004

Referential communication disturbances in the speech of nonschizophrenic siblings of schizophrenia patients.

Several different types of communication disturbances have been identified in the speech of schizophrenia patients. This study assessed 6 types of referential communication disturbances in the speech of 32 stable outpatients, 23 of their nonschizophrenic siblings, and 27 control subjects. The siblings made more frequent reference failures of all types than control subjects and did not differ from the patients on most types of disturbance. Only on the arguably most "schizophrenic" type of disturbance, the missing information reference, did patients show more deviance than siblings. On the vague reference, siblings showed more deviance than patients. These results, which are very similar to those previously reported on parents of patients, support the idea that referential disturbances reflect vulnerability to schizophrenia.

Adult↗
PubMed2003

Augmented sympathetic neural response to simulated obstructive apnoea in human heart failure.

Sleep apnoea in heart failure increases mortality risk, possibly as a result of greater activation of the sympathetic nervous system. In healthy subjects, simulated central apnoeas (holding breath) and obstructive apnoeas (Mueller manoeuvres) increase muscle sympathetic activity equally, primarily through chemoreceptor stimulation. In heart failure, however, Mueller manoeuvres cause greater reductions in blood pressure than breath holds. We hypothesized that in heart failure, the summation of arterial baroreceptor unloading and chemoreceptor stimulation would increase sympathetic activity more during obstructive than central apnoeas. Healthy human subjects and heart failure patients (seven of each) performed 15-s breath holds and 15-s Mueller manoeuvres. Breath holds evoked a progressive increase in muscle sympathetic nerve activity in both groups, but had no effect on blood pressure. In healthy subjects, breath holds and Mueller manoeuvres caused equal peaks in sympathetic activity. In contrast, in heart failure patients, Mueller manoeuvres caused a progressive decrease in blood pressure (P < 0.05) and greater increases in sympathetic activity than breath holds (P < 0.01). In heart failure, simulated obstructive apnoea elicits greater increases in sympathetic activity than simulated central apnoea, due to its additional hypotensive effect. These present findings offer novel insight into the potential role of sleep apnoea in augmenting sympathetic activity and accelerating disease progression in heart failure.

Aged↗
PubMed2002

A controlled, prospective screening study of celiac disease presenting as iron deficiency anemia.

BACKGROUND: anemia is the most frequent presenting feature of celiac disease in adults using endomysial antibody (EmA) screening. Endomysial antibody screening of anemia may allow detection of celiac disease at an earlier stage of investigation and after a shorter duration of symptoms. The characteristics of celiac patients identified by screening require further study. GOALS: a goal of this study was to evaluate the prevalence of celiac disease in adult patients with iron deficiency anemia compared with a nonanemic control population using immunoglobulin A (IgA) EmA screening. We also studied the positive predictive value (PPV) of the EmA assay and correlated the severity of histologic abnormalities in distal duodenal biopsy samples with EmA and tissue transglutaminase (tTG) antibody titer. STUDY: four hundred eighty-four patients with microcytic, hypochromic anemia underwent IgA EmA assay. Four hundred ninety-eight nonanemic age- and sex-matched patients from the same source comprised the control group. Patients with positive serology results were invited for endoscopic duodenal biopsies. RESULTS: one in 44 anemic patients was diagnosed with histologically confirmed celiac disease compared with one in 498 nonanemic patients ( < 0.01). Fifty percent of women were premenopausal, and 25% of patients were older than 65 years. The PPV for EmA assay varied between 73% and 93% for anemic patients and improved at higher antibody titer, with all false-positive results occurring at the lowest titers. CONCLUSIONS: screening for celiac disease using IgA EmA assay is effective in anemic patients, including premenopausal women and patients older than 65 years, and it can be recommended in clinical practice.

Adult↗