Biomedical subjects
Publications and source records attributed to T Phillips.
A study was conducted concerning the frequency of litter deposits in a single experimental trash receptacle located in a high-use, urban park setting. There were four two-week periods of alternating no-contingency, contingency conditions during which reinforcement and incentive were evaluated. It was found that reinforcement resulted in the highest rates of behavior and improvements in the aesthetic appearance of the area.
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A new, more reactive group of protein cross-linkers in the class of equilibrium transfer alkylating cross-link (ETAC) reagents has been synthesized. These compounds include alpha,alpha-bis[(p-chlorophenyl)methyl]- and alpha,alpha-bis[(p-tolylsulfonyl)methyl]acetophenones substituted in the acetophenone ring with chloro, nitro, amino, and carboxyl groups and derivatives. Included are an 125I-labeled ETAC reagent and a 111In-labeled DTPA (diethylenetriaminepentaacetic acid) ETAC for site direction and biodistribution studies. These ETAC compounds were reacted with unreduced and partially reduced antibody under mild pH (pH 4-8) and room temperature conditions to give cross-linked structures. Examination of resultant cross-linked antibody via size-exclusion HPLC, sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis, and an enzyme linked immunosorbent assay revealed that (1) both interantibody as well as intraantibody cross-linking had occurred; (2) the level of inter- and intraantibody cross-linking varied with the substituent on the ETAC; (3) the stability of the cross-links on the reducing SDS gels varied with substituents on the ETAC; (4) little if any immunoreactivity was lost after reaction with one of the more effective ETAC cross-linking compounds; (5) the 125I-labeled ETAC sulfhydryl cross-linking in partially reduced antibody increased with pH whereas amine cross-linking with the unreduced antibody decreased with pH; (6) the optimum pH for sulfhydryl site direction was pH 5.0; (7) the 111In DTPA ETAC labeled antibody had a biodistribution in CD1 mice similar to that of the 111In bis cyclic anhydride DTPA labeled antibody.
OBJECTIVE: The goal of the study was to evaluate the significance of delayed laboratory analysis of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol for prenatal screening. METHODS: Biochemical analysis of 30 consecutive biochemical screening specimens of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol was performed immediately upon arrival to the laboratory, 7 days later, and again 14 days after maternal blood was drawn. Differences among the results of the three sets of biochemical studies were evaluated by one-way analysis of variance for repeated measures. RESULTS: No significant differences were found among the results of immediate assays as compared with those at a 7- or a 14-day delay for all three biochemical markers. CONCLUSIONS: Our data suggest that up to a 14-day delay in the performance of the 2nd-trimester maternal serum biochemical screening assays will not alter the results significantly. The results of maternal serum screening are, thus, clinically valid even if the laboratory assays were performed several days after maternal blood was drawn.
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Respiratory inductance plethysmography (RIP) is used to measure ventilation from two measurements of body surface movements (rib-cage and abdomen) via the application of volume-motion (V-M) coefficients. The correct derivation of both V-M coefficients (calibration) is necessary because there are considerable spontaneous variations in relative contributions from these two compartments even during resting breathing. In order to fully test a calibration, deliberate changes in rib-cage (RC) to abdominal (AB) contribution must be made. We used this approach to test two single-posture calibration techniques, multiple linear regression (MLR) and isovolume (ISV). Ten normal subjects and nine patients with chronic airway obstruction (CAWO) were studied using quiet breathing throughout. We also studied the effects of changing posture on the constancy of the V-M coefficients. MLR proved a little more accurate (p = 0.03) in deriving the V-M coefficients than ISV in normal subjects, and ISV consistently underestimated the AB V-M coefficient relative to RC. No difference between the two techniques existed in patients with CAWO. Both MLR and ISV calibrations failed to give acceptable calibrations in some patients. When MLR calibration was used, a deliberate 20% change in relative compartmental contribution (RC-AB) induced mean errors in RIP estimations of tidal volume of 3.5 and 9.5% in normal subjects and patients respectively. When there were no deliberate changes in relative contribution, the 95% confidence limits of individual tidal volume estimates were +/- 6.6 and +/- 12% in normal subjects and patients respectively. MLR calibration provides a statistical estimate of its quality at the time of V-M coefficient derivation.(ABSTRACT TRUNCATED AT 250 WORDS)