Biomedical subjects

M Spafford

Publications and source records attributed to M Spafford.

5 recordsLinked to original sources

PubMed2003

'Talking the talk': school and workplace genre tension in clerkship case presentations.

BACKGROUND: Socialisation into a community involves learning sanctioned ways of talking. This study investigates the case presentation genre as a site of socialisation into the clinical community of practice. METHODS: Sixteen oral case presentations and the teaching exchanges surrounding them (involving 11 students and 10 faculty members) were observed by paired researchers during inpatient paediatric medicine rounds. A total of 21 in-depth interviews were conducted with 11 students and 10 faculty. Both data sets were audio-recorded, transcribed and analysed for emergent themes and rhetorical strategies. RESULTS: Students emphasised case presentation as a school genre and described the ideal presentation as free of interruptions. As a consequence, students' presentation strategies were directed towards getting through the presentation without questions. In contrast, faculty responses suggested an understanding of the genre as a way of constructing shared professional knowledge. Faculty feedback was often explicit about critical issues in constructing shared knowledge, such as handling uncertainty. However, student presentations rarely reflected this feedback. CONCLUSIONS: The school genre described and enacted by students conflicts in key ways with the workplace genre evident in faculty feedback, suggesting that school and workplace iterations of case presentation may be at cross-purposes. Such cross-purposes have implications, because when students and teachers perceive a genre differently, a 'gap' is created in their interactions. Even rich and contextually situated feedback may get lost or distorted as it crosses this gap. Explicit acknowledgement of the multiple and flexible iterations of case presentation will improve the learning that novices experience through acquiring this central form of professional 'talk'.

Case Management↗

PubMed2001

Microsatellite instability at AAAG repeat sequences in respiratory tract cancers.

We surveyed the occurrence of novel alleles at microsatellite sequences in non-small cell lung cancers (NSCLC) using 61 tetranucleotide repeat markers. The presence of at least one new allele, consistent with microsatellite instability (MSI), was observed in 26 of 61 (43%) markers involving 30 of 47 (64%) NSCLC. Twelve of the 26 markers detected new alleles in 2 or more tumors and 11 of these 12 markers contained an AAAG repeat sequence. Using this panel of 12 markers, MSI was detected in 24 of 47 (51%) NSCLC and 10 of 18 (56%) head and neck cancers but was only observed in 8 of 38 (21%) bladder cancers and 3 of 25 (12%) kidney cancers. Our results suggested that about 50% of respiratory tract cancers exhibited microsatellite instability predominantly at AAAG sequences. This distinct type of instability was termed EMAST for elevated microsatellite alterations at selected tetranucleotide repeats. The identification of markers with EMAST should have potential application for the molecular detection of respiratory tract cancers.

Aged↗

PubMed2000

Evidence for a causal association between human papillomavirus and a subset of head and neck cancers.

BACKGROUND: High-risk human papillomaviruses (HPVs) are etiologic agents for anogenital tract cancers and have been detected in head and neck squamous cell carcinomas (HNSCCs). We investigated, retrospectively, an etiologic role for HPVs in a large series of patients with HNSCC. METHODS: Tumor tissues from 253 patients with newly diagnosed or recurrent HNSCC were tested for the presence of HPV genome by use of polymerase chain reaction (PCR)-based assays, Southern blot hybridization, and in situ hybridization. The viral E6 coding region was sequenced to confirm the presence of tumor-specific viral isolates. Exons 5-9 of the TP53 gene were sequenced from 166 specimens. The hazard of death from HNSCC in patients with and without HPV-positive tumors was determined by proportional hazards regression analysis. RESULTS: HPV was detected in 62 (25%) of 253 cases (95% confidence interval [CI] = 19%-30%). High-risk, tumorigenic type HPV16 was identified in 90% of the HPV-positive tumors. HPV16 was localized specifically by in situ hybridization within the nuclei of cancer cells in preinvasive, invasive, and lymph node disease. Southern blot hybridization patterns were consistent with viral integration. Poor tumor grade (odds ratio [OR] = 2.4; 95% CI = 1.2- 4.9) and oropharyngeal site (OR = 6.2; 95% CI = 3.1-12.1) independently increased the probability of HPV presence. As compared with HPV-negative oropharyngeal cancers, HPV-positive oropharyngeal cancers were less likely to occur among moderate to heavy drinkers (OR = 0.17; 95% CI = 0.05-0.61) and smokers (OR = 0.16; 95% CI = 0.02-1.4), had a characteristic basaloid morphology (OR = 18.7; 95% CI = 2.1-167), were less likely to have TP53 mutations (OR = 0.06; 95% CI = 0.01-0. 36), and had improved disease-specific survival (hazard ratio [HR] = 0.26; 95% CI = 0.07-0.98). After adjustment for the presence of lymph node disease (HR = 2.3; 95% CI = 1.4- 3.8), heavy alcohol consumption (HR = 2.6; 95% CI = 1.4-4.7), and age greater than 60 years old (HR = 1.4; 95% CI = 0.8-2.3), all patients with HPV-positive tumors had a 59% reduction in risk of death from cancer when compared with HPV-negative HNSCC patients (HR = 0.41; 95% CI = 0.20-0.88). CONCLUSIONS: These data extend recent molecular and epidemiologic studies and strongly suggest that HPV-positive oropharyngeal cancers comprise a distinct molecular, clinical, and pathologic disease entity that is likely causally associated with HPV infection and that has a markedly improved prognosis.

Adolescent↗

PubMed1989

Response of isolated working hearts to fatty acids and carnitine palmitoyltransferase I inhibition during reduction of coronary flow in acutely and chronically diabetic rats.

The effects of palmitate on mechanical failure of ischemic hearts were studied in acutely (48-hour) and chronically (6-week) streptozotocin diabetic rats. Coronary flow was reduced by 50% in isolated working hearts perfused at a 15 cm H2O preload and 100 mm Hg afterload by the one-way ball valve model of ischemia. Peak systolic pressure (PSP) and cardiac output (CO) decreased 40% by 4 minutes in control hearts perfused with 11 mM glucose and paced at 280 beats/min, compared with 50% in hearts from acutely diabetic rats. Addition of 1.2 mM palmitate to the perfusate accelerated failure rates, with PSP and CO decreasing 65% and 80% by 4 minutes in control and acutely diabetic rat hearts, respectively. In chronically diabetic rats, mechanical function could not be maintained in palmitate-perfused hearts paced at 280 beats/min, even in the absence of ischemia. If these hearts were paced at 250 beats/min and subjected to ischemia, PSP and CO decreased 90% by 4 minutes, regardless of whether palmitate was added to the perfusate. Under these conditions, PSP decreased less than 10% by 4 minutes in both palmitate- or glucose-perfused control hearts. Etomoxir (10(-9) M), a carnitine palmitoyltransferase I inhibitor, markedly decreased the rate of mechanical failure in both acutely and chronically diabetic rat hearts, in the presence and absence of palmitate. The beneficial effect of Etomoxir on mechanical function did not occur as a result of a decrease in either myocardial long chain acyl-coenzyme A or long chain acylcarnitine levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1985

Modification of pattern reversal VERs by ocular accommodation.

The amplitudes and implicit times of the P-1 component of monocular transient pattern VERs elicited by reversing checkerboard targets were measured in 6 conditions: (1) Ocular accommodation (Ao) elicited by minus power ophthalmic lenses; (2) Ao stimulated by minus lenses with the natural pupil of the test eye dilated and replaced by an artificial pupil; (3) accommodative demand and pupil size fixed with retinal image size (Ir) changed by afocal minifying lenses, (4) accommodative demand and Ir fixed but pupil size changed; (5) Ao elicited by minus lenses for three sizes of reversing checkerboards, and (6) Ao elicited by minus lenses for a constant checkerboard size with three check sizes. The observed decrease in VER amplitude with Ao could not be attributed entirely to the effects of pupil size or Ir. The rate at which the amplitude of P-1 decreased with Ao was not affected by checkerboard check size, but was closely correlated with checkerboard field size. The implicit time of P-1 first decreased slightly below baseline values at low and moderate levels of Ao and then tended to increase significantly at higher levels. The increase in implicit time at high levels of Ao could be explained adequately by the effects of pupil size alone on the VER. However, where Ao occurred without pupillary miosis, the increase in implicit time could only be explained by focusing error.

Accommodation, Ocular↗