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Biomedical subjects

G Rosenquist

Publications and source records attributed to G Rosenquist.

6 recordsLinked to original sources

Tuberculosis testing. Physician attitudes and practice.

OBJECTIVE: To assess physician agreement with and adoption of American Academy of Pediatrics' (AAP) recommendations on tuberculosis screening in children. DESIGN AND PARTICIPANTS: Survey of a random sample of 1272 community pediatricians and family physicians (excluding academic institutions) in 4 mid-Atlantic states and the District of Columbia. RESULTS: The response rate was 66%. Seventy-five percent of the respondents were aware of the 1994 AAP screening recommendations. Most (64%) test children at low risk periodically (at age 1 year, preschool age, and adolescent age), and 81% test children at high risk annually. Eighty-one percent of the respondents estimated that 10% or less of their patients were at high risk for tuberculosis. Most use patient-specific factors, geographic or community prevalence, or both as principal criteria to determine risk. Eighty-seven percent used multiple-puncture tests in 1993; this declined to 55% in 1994. Multiple-puncture tests are still used exclusively by 29% of the respondents. Ninety-one percent of those using multiple-puncture tests and 19% of those using the Mantoux test allow parents to read the test reaction. Forty-six percent of the respondents believed that if a return visit was required for reading the test reaction, 50% or less of their patients would return. Only 22% of the respondents adhere to the 1994 AAP recommendations regarding frequency, testing method, and reading the test reaction. Factors associated with adherence to AAP recommendations included physician and practice characteristics and knowledge of AAP recommendations. CONCLUSIONS: Physician practice of tuberculosis testing varies widely; most do not adhere to the 1994 AAP recommendations. Most physicians vary the frequency and testing method based on a patient's risk status. The use of multiple-puncture tests has declined, although they are still widely used. Accurate reading of screening tests remains a major concern.

Adolescent↗

Evidence that CCK-58 has structure that influences its biological activity.

Many biologically active peptides exist in multiple molecular forms, but the functional significance of regions outside the region of bioactivity is unknown. The biological and immunological data presented in this study indicate that cholecystokinin-58 (CCK-58), unlike other forms of cholecystokinin, has structure that influences its bioactivity. CCK-58 was purified from acid extracts of canine intestinal mucosa until a single absorbance peak was obtained during reverse-phase chromatography. Amino acid analysis precisely determined the peptide concentrations of purified CCK-58 and synthetic CCK-8. Our hypothesis was that if the amino terminus of CCK-58 influences its bioactivity then its activity would be modified when this region was removed from the peptide. To evaluate the importance of the amino terminus of CCK-58 to influence its biological activity, the abilities of CCK-58 and CCK-8 to release amylase from pancreatic acini were compared before and after tryptic digestion. Tryptic digestion of CCK-58 decreased the half-maximal stimulation (EC50) for amylase release from 96 to 28 pM. The EC50 for digested CCK-58 was similar to that for CCK-8 (17 pM). These results suggest that CCK-58 has a structure that shields its bioactive carboxyl terminus. This is further supported by the finding that carboxyl fragments generated from CCK-58 by trypsin or by partial acid hydrolysis were greater than twofold more immunoreactive than the intact CCK-58. The diminished activity of CCK-58 SK shields the carboxyl terminus, which is important to its biological and immunological activities.

Acids↗

Cholecystokinin-like immunoreactivity in frog retina: localization, characterization, and biosynthesis.

We sought to localize and characterize cholecystokinin-like immunoreactivity (CCK-LI) in frog retinal tissues, CCK-LI was present in concentrations of 2.20 +/- 0.19 pmol/g wet weight (mean +/- SE, n = 6) in water extracts of frog retina and 0.23 +/- 0.04 pmol/g in acid extracts. The predominant form of CCK-LI co-eluted with the octapeptide of CCK on Sephadex G50 column chromatography. A minor form which eluted as a molecule larger than the 39 amino acid form of CCK was found only in the acid extracts. By immunohistochemistry, CCK-LI was localized to amacrine cells which give rise to processes ramifying in the distal 2/3 of the inner plexiform layer. Time dependent uptake of 35S-methionine into CCK-LI was observed in cultured frog retinas and this uptake was blocked with 0.2 mM cycloheximide. Our findings suggest that the retina may be a useful system for further characterization of the neural function of CCK-LI.

Animals↗

Effect of food-deprivation on rat pancreatic islet cells.

Somatostatin, insulin and glucagon concentrations in rat pancreas were measured following various intervals of food-deprivation. Tissue concentrations, as measured by radioimmunoassay, were correlated with A-, B-, and D-cell number and size using a scanning integrating image analyzer (Quantimet 720). Alterations in total islet hormone content were not correlated to changes in size or distribution of cells. This implies that changes in tissue content reflect changes in turnover of peptides rather than changes in cell size or number.

Animals↗