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Biomedical subjects

P J Sullivan

Publications and source records attributed to P J Sullivan.

29 records · Page 2Linked to original sources

Regional variation of cytosol androgen receptors throughout the diseased human prostate gland.

The heterogeneous histology of the normal and diseased human prostate is well established. This study has investigated variations in cytosol androgen receptor (AR) content throughout the diseased gland to establish the most suitable sites to obtain tissue for AR assay. Only then can AR be investigated as a potential predictor of response to endocrine treatment. In a transverse slice of an enucleated prostate showing benign prostatic hyperplasia (BPH) AR levels in 1-g segments varied from 109 to 1,212 fmol/g tissue (mean 483 +/- 273; median 406), with no negative areas. Areas of higher receptor concentrations corresponded to the glandular regions of sections obtained from a slice taken in juxtaposition; areas of low receptor concentrations corresponded to the stromal regions. A significant correlation (P less than .02) was observed between AR concentration and the proportion of glandular components of each segment. Specimens were also obtained from each of three sites from 38 prostates; 45% of all specimens contained AR; however, distribution of receptor throughout the prostate was uneven. AR were significantly more likely to be measured in the peripheral zone (71% positive) than in periurethral tissue (39% positive) whilst only 24% of specimens taken from the limit of the resection possessed AR binding capacity. Similar distribution patterns were observed in both benign and malignant prostates, although 16% more specimens from carcinomatous prostates contained receptor than did those from benign glands; this difference was maintained at each site. In addition receptor levels were consistently lower in benign than in malignant specimens. It is therefore desirable to know the histological composition of specimens used for AR measurement.

Cytosol↗

Technegas--a new ventilation agent for lung scanning.

A simple process using technetium-99m generator eluate in a graphite crucible at 2500 degrees C, produces a structured ultra-fine dispersion of labelled carbon. Particle sizes are 5.0 nm (0.005 micron) and less and adhere to the walls of the alveoli on inhalation. Penetration characteristics are gas-like and the radioactivity per litre of carrier argon allows single breath inhalations of a diagnostic dose. Over 190 patients have been studied including 50 within a formal clinical trial with xenon-133. Results of tomography, dynamic inhalation, and image subtraction using this new agent-'Technegas'--are presented.

Carbon↗

The effect of eating on thallium myocardial imaging.

To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The 201Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of 201Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed 201Tl images causes increased 201Tl myocardial clearance rates and may alter 201Tl myocardial redistribution over time.

Adult↗

Lung ventilation studies with technetium-99m Pseudogas.

Technetium-99m Pseudogas is an ultrafine near monodisperse aerosol of 0.12-microgram diam particle size. This report describes initial clinical experiences with 27 patients referred for investigation of suspected pulmonary embolism, and in whom Pseudogas ventilation images were compared with a high quality commercial aerosol. An additional group of ten patients with severe COPD was examined in a comparative trial of Pseudogas with 81mKr. Pseudogas was better than a conventional aerosol in reaching a diagnosis of pulmonary embolism using a simple blinded comparison with coded images. In addition, bronchial deposition was minimal unless COPD was severe. Moderately well patients had no difficulty inhaling the necessary activity in one or two breaths, and even severely ill and frail aged persons could accomplish the passive breathing maneuver in less than a minute. Clearance of Pseudogas was directly to the systemic circulation with a half-time of 10 min in normal subjects extending up to 100 min in patients with airways disease.

Adolescent↗

A comparison of the technetium-labeled myocardial agents DiArs and DMPE to 201Tl in experimental animals.

The biodistribution, kinetics, imaging characteristics and blood flow correlations of 99mTc labeled DiArs and DMPE were studied. The mice biodistribution were compared to 201Tl in mice and dogs, respectively. The myocardial kinetics of these agents were evaluated in normal and ischemic myocardium using miniaturized endocardial detectors. DiArs had a lower myocardial concentration (9.4 +/- 0.8% dose/g at 1 min), than DMPE (11.7 +/- 1.1% dose/g at 1 min) but both were considerably less than 201Tl (23-26% dose/g at 1 min). The kinetic characteristic of both technetium labeled agents suggested that redistribution into ischemic myocardium would not take place, since the clearance rate from normal and ischemic myocardium was similar for both the DiArs and DMPE . The clear visualization of the canine myocardium after i.v. injection demonstrated the superiority of DMPE over DiArs and the potential use of these agents, if proven, to behave the same in human trials.

Animals↗

An ambulatory ventricular function monitor: validation and preliminary clinical results.

A device for the continuous measurement of left ventricular (LV) function was tested in a series of 34 subjects. The instrument consisted of 2 arrays of radiation sensitive cadmium telluride detectors held in place over the region of the left ventricle and lung by a vest-like garment (hence the name VEST). The VEST electronic instrumentation included analog-to-digital converters, a battery pack, microprocessor and gating device, which were worn in a back pack. Data generated by the VEST, including the digitized average electrocardiogram, RR interval, counts/13 ms in each radiation detector, and time since commencement of data recording, were recorded on a cassette tape recorder every 2 minutes for subsequent analysis. At the conclusion of conventional multigated blood pool imaging, the VEST was positioned and worn by the subjects while supine, standing in place and walking. The correlation of ejection fraction calculated independently from the VEST and scintillation camera data was greater than 0.95. The inter-record reproducibility of the ejection fraction measured by the VEST in sedentary subjects was less than 3%.

Ambulatory Care↗

Direct evidence of monocyte recruitment to inflammatory bowel disease mucosa.

Alterations in phenotype and function of intestinal macrophages occur in inflammatory bowel disease (IBD) but it is unclear whether these changes result from the recruitment of circulating monocytes to the intestine or from proliferation of resident intestinal macrophages. We sought to demonstrate the arrival of blood monocytes, the precursors of macrophages, in IBD mucosa. Peripheral blood mononuclear cells were isolated from 23 patients with clinically active intestinal inflammation (13 Crohn's disease, eight ulcerative colitis, two infective colitis), then radiolabelled with 99mtechnetium (Tc)-stannous colloid (n = 13) or 111indium (In)-oxine (n = 10) before re-injection and abdominal scanning. Four patients had demonstrable intestinal monocyte uptake using [99mTc]-stannous colloid, while six [111In]-oxine-labelled monocyte scans were positive. Uptake sites correlated with actively inflamed regions. Patients demonstrating monocyte uptake had been treated with corticosteroids for a significantly (P < 0.02) shorter duration (median 3 vs 20 days) than those with negative scans. There was no significant difference between positive and negative scans for disease category, clinical or histological disease, activity, or radioisotope used. Biopsies of inflamed mucosa from two patients suffering ulcerative colitis who had positive scans showed a high proportion of CD14-positive macrophages, 4-9% of which contained autoradiographic grains. These results demonstrate that blood monocytes are recruited to the mucosa of actively inflamed bowel, and suggest that this process may be inhibited by corticosteroids. Moreover, the phenotype of the recently-arrived monocytes indicates their susceptibility to stimulation by lipopolysaccharide, and suggests a mechanism for the continuing inflammation in the bacterial product-rich milieu of IBD.

Adolescent↗

CYTYC Corporation.

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Clinical Trials as Topic↗

Introduction of Aedes albopictus into a La Crosse virus--enzootic site in Illinois.

In late summer and fall 1997, Aedes albopictus mosquitoes were found in Peoria, Illinois, a long recognized focus of La Crosse virus transmission. Larvae were found in tires and other artificial containers, biting adults were recovered, and eggs were collected in oviposition traps within a 25-ha area. One chipmunk trapped < 0.25 km from the infested area tested positive for neutralizing antibodies against La Crosse virus.

Aedes↗