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Biomedical subjects

David Hull

Publications and source records attributed to David Hull.

5 recordsLinked to original sources
PubMed2006

Investigations in subjects with cough following upper respiratory tract infection.

The study aimed to investigate subjects with cough following acute upper respiratory tract infection (URTI), and to compare those subjects unable to suppress cough ("non-suppressors") with those who were able to suppress cough ("suppressors"). Forty-three URTI subjects participated, 31 with cough associated with acute URTI and 12 healthy controls; 21 of the coughing subjects were "suppressors", 10 were "non-suppressors". We obtained responses to chemical and mechanical stimulation of the nasal cavity or the pharynx using both psychophysical measures and event-related potentials. The study provided the following results: (1) "non-suppressors" did not exhibit significantly different intensity ratings or event-related potentials in comparison to "suppressors" in terms of responses to intranasal irritant, mechanical, or olfactory stimuli; (2) when pharyngeal mechanical stimuli were investigated "suppressors" rated the stimuli as more intense than "non-suppressors" and controls; (3) latencies of event-related potentials to pharyngeal stimuli were longest in "non-suppressors". Keeping in mind the relatively small sample size, it appears possible to differentiate certain types of cough during uncomplicated URTI. This may help to explain interindividual differences in responsiveness to cough medication.

Adolescent↗
PubMed2005

Primary carcinoid tumor of the common hepatic duct: A rare case with immunohistochemical and molecular findings.

We report immunohistochemical (IHC) and molecular findings in a rare case of a carcinoid tumor of the extrahepatic bile ducts in a 33-year-old woman, who presented with a 3.9x2.8x2.6 cm mass within the right and common hepatic ducts. She underwent surgery and a carcinoid tumor was identified. This lesion is of interest because in addition to the morphological and cytological features of a typical carcinoid, it demonstrated a distinct pleomorphic area immunoreactive for gastrin. By molecular analysis, loss of heterozygosity (LOH) with opposite allelic patterns between the gastrin-positive and gastrin-negative areas of the tumor was identified. The molecular studies for LOH along with the morphology and IHC profiling suggest that this second population of gastrin-positive carcinoid cells may represent a new clone within the carcinoid tumor with differentiation toward gastrin production or may represent the next step in the carcinogenic process with a gradual emergence of a more aggressive clone.

Adult↗
PubMed2002

Assessment of pharyngeal sensitivity to mechanical stimuli using psychophysical and electrophysiological techniques.

The investigation was aimed to assess pharyngeal sensitivity by means of intensity ratings and event-related potentials (ERPs) to mechanical stimulation. Twenty healthy subjects participated (14 female, mean age 23.6 years). Both intensity ratings and ERP were obtained in response to three intensities of mechanical stimuli (air puffs) applied to the nasal cavity or the pharynx. Test-retest reliability was investigated for two sessions performed on different days. The study provided the following: (1) intensity ratings of nasal or pharyngeal stimuli increased with increasing stimulus intensity (P < 0.001); (2) they also exhibited a significant test-retest reliability (r </= 0.78) which was best for higher stimulus intensities; (3) ERP amplitudes increased and latencies shortened with increasing stimulus intensity (factor 'intensity': P < 0.013); (4) test-retest reliability was best at centro-frontal recording sites where significant correlations were found for both ERP amplitudes and latencies; (5) ERP to pharyngeal stimulation correlated significantly with perceived stimulus intensity (e.g., latency N1 at Cz: r = -0.73, P = 0.001). In conclusion, mechanical stimulation of the pharynx can be applied to reliably elicit ERPs which are related to both stimulus intensity and intensity ratings. This model may be useful in the investigation of cough-related changes in pharyngeal sensitivity.

Adult↗