Biomedical subjects

Mark Allen

Publications and source records attributed to Mark Allen.

25 records · Page 2Linked to original sources

PubMed2003

Potential environmental impact of a hydrogen economy on the stratosphere.

The widespread use of hydrogen fuel cells could have hitherto unknown environmental impacts due to unintended emissions of molecular hydrogen, including an increase in the abundance of water vapor in the stratosphere (plausibly by as much as approximately 1 part per million by volume). This would cause stratospheric cooling, enhancement of the heterogeneous chemistry that destroys ozone, an increase in noctilucent clouds, and changes in tropospheric chemistry and atmosphere-biosphere interactions.

Journal Article↗

PubMed2003

Morphological decomposition involving non-productive morphemes: ERP evidence.

It is generally believed that readers decompose a complex word into its constituent morphemes only when those morphemes participate productively in word formation. Here we recorded event-related potentials (ERPs) to words (e.g. muffler, receive), non-words containing no morphemes (e.g. flermuf), and non-words containing a prefix and a non-productive bound stem (e.g. in-ceive). Prior work has shown that pronounceable non-words elicit larger-amplitude N400 components than words. If readers treat non-words containing non-productive morphemes as unanalyzed wholes, then these non-words should elicit larger N400 s than matched words. We report here, however, that bound-stem non-words elicit a brain response highly similar to that elicited by real words. This finding suggests that morphological decomposition and representation extend to non-productive morphemes.

Adult↗

PubMed2003

Validation of self-reported cancers in the California Teachers Study.

Self-reported cancer data from the California Teachers Study were validated by using California Cancer Registry data. The California Teachers Study cohort consists of 133,479 active and retired California teachers. In 1995-1996, data from a mailed questionnaire were linked to the California Cancer Registry data. Sensitivity and specificity of 11 types of cancer were calculated. Multivariate analyses were conducted to evaluate correlates of false-positive and false-negative reporting. Sensitivities showed great variation by cancer site. The highest sensitivities were observed for breast (96.4%) and thyroid (92.9%) cancers, whereas the lowest sensitivities were those for cervical (44.3%), endometrial (69.1%), and other skin (53.6%) cancers. The sensitivities for in situ cancers (at the time of diagnosis) were considerably lower than those for invasive cancers in about half of the cancer types surveyed. The specificities for individual cancer sites ranged from 90% to 99%; the highest were those for lung cancer, leukemia, and Hodgkin's disease (all 99.9%). The lowest specificity was for other skin cancer (90.2%). In situ stage at diagnosis and older age were significantly associated with false-positive reporting. Age and non-White race were associated with false-negative reporting. These findings suggest that the feasibility of using self-reported data without verification in epidemiologic studies of cancer varies by site.

Adult↗

PubMed2002

The structure of an FF domain from human HYPA/FBP11.

The FF domain is a 60 amino acid residue phosphopeptide-binding module found in a variety of eukaryotic proteins including the transcription elongation factor CA150, the splicing factor Prp40 and p190RHOGAP. We have determined the structure of an FF domain from HYPA/FBP11. The domain is composed of three alpha helices arranged in an orthogonal bundle with a 3(10) helix in the loop between the second and third alpha helices. The structure differs from those of other phosphopeptide-binding domains and represents a novel phosphopeptide-binding fold.

Amino Acid Sequence↗

PubMed2002

High breast cancer incidence rates among California teachers: results from the California Teachers Study (United States).

OBJECTIVE: [corrected] To determine risk factor profiles and cancer incidence rates among participants in the California Teachers Study (CTS), a study designed to document high breast cancer incidence rates of California teachers and to investigate emergent hypotheses in the etiology of breast and other cancers. METHODS: The CTS is a prospective study of 133,479 California female teachers and administrators, established in 1995-1996 with members of the California State Teachers Retirement System completing a detailed mailed questionnaire regarding possible risk factors for breast and other cancers. Cancer outcomes were identified by linkage with the California Cancer Registry. RESULTS: CTS participants have a 51% higher age-standardized invasive breast cancer incidence rate and a 67% higher in-situ breast cancer incidence rate than would be expected based on race-specific statewide rates after three years of follow-up. CTS participants also have substantially elevated rates of endometrial cancer (rate ratio, RR = 1.72), ovarian cancer (RR = 1.28), melanoma (RR = 1.59), non-Hodgkin's lymphoma (RR= 1.53), and leukemia (RR = 1.28), but low rates of invasive cervix cancer (RR = 0.53) and lung cancer (RR = 0.66). CONCLUSIONS: CTS members have high rates of several major cancers, particularly breast cancer, and low rates of lung and cervix cancer. Although late age at first birth can explain a portion of the observed excess risk of breast cancer in this cohort, the unique risk factor profile of CTS members may account for much of their higher risk of breast and selected other cancers. The CTS offers a rich resource for future studies of cancer risk and of women's health, in general.

Adult↗

PubMed2002

Occult lymph node metastases as a predictor of tumor relapse in patients with node-negative esophageal carcinoma.

BACKGROUND & AIMS: Esophageal carcinoma is an aggressive disease with a very poor prognosis. Early tumor relapse after surgical resection in patients with node-negative esophageal carcinoma suggests that occult metastases may have been missed at the original pathologic examination. The aim of this study was to determine the prevalence of immunohistochemically detected occult lymph node microscopic metastases in patients with pathologic N0 esophageal carcinoma and the impact of these occult metastases on relapse-free survival. METHODS: All patients (n = 124) with pathologic N0 esophageal carcinoma undergoing resection at our institution between January, 1994, and October, 1998, constituted the study population. Esophagectomy specimens were reevaluated by immunohistochemistry (monoclonal antibody against cytokeratin AE1/AE3). Clinical and pathologic features were summarized, and patient relapse-free survival was estimated. RESULTS: Among the total of 124 patients, occult lymph node microscopic metastases were identified by immunohistochemistry in 14 patients (11%) (T1 mucosa, 4%; T1 submucosa, 6%; T2, 22%; and T3, 14%). Patients were followed for a median of 3.2 years. Relapse-free survival was not significantly associated with the presence of occult lymph node microscopic metastases as detected by immunohistochemistry (P = 0.12). Advanced T stage (T3; P < 0.001) and lymphovascular invasion (P < 0.001) were found to be associated with tumor relapse. CONCLUSIONS: In the present study, occult lymph node microscopic metastases in pathologic N0 esophageal carcinoma patients were less frequent than previously reported. T stage and lymphovascular invasion were significantly associated with relapse-free survival, although a significant association with occult lymph node metastases was not detected.

Blood Vessels↗

PubMedDate not supplied

Stem homographs and lemma level representations.

Previous studies have found that priming a target like cerr-o ("hill") with an unmasked stem-homograph (e.g., cerr-ar, "to close") or with an unmasked allomorph of a stem-homograph (e.g., cierr-a, "he/she/it closes") has an inhibitory effect on target recognition. We report evidence from stem-homograph priming studies that implicate both morphological parsing and lexical selection processes at the lemma level. We argue that stem-homograph inhibition is the product of lexical selection mechanisms that are engaged just when a fully ambiguous stimulus (here, an inflectional stem) must be assigned one of its viable interpretations in order to afford conscious perception of lexical identity.

Cognition↗