PubMed Health⌕ Search

Biomedical subjects

A K Adams

Publications and source records attributed to A K Adams.

At least 37 records · Page 2Linked to original sources
PubMed1991

Standardization of a multi-wavelength UV detector for liquid chromatography-based toxicological analysis.

The performance of a multi-wavelength UV detector for automated drug identification following liquid chromatographic separation was evaluated. The ability of selected wavelength ratios to distinguish two closely related drugs was considered at different concentrations. Calibration of the detector based on wavelength ratios was then utilized to standardize two different detectors and to evaluate instrument-to-instrument variation of a series of detectors. Reproducibility of the second-derivative zero intercept for these drug spectra was also evaluated. Standardization of detector performance by reference to these two parameters permitted the transfer of UV spectral libraries stored on one instrument to another without compromising the reliability of qualitative data.

Amphetamines↗
PubMed1991

Identification of drugs in physiological fluids following on-line liquid chromatographic purification and analysis.

This paper describes the application of an automated algorithm for drug identification following the liquid chromatographic on-line separation and purification of drugs in physiological fluids. Two hundred fifty-seven (257) drugs and 45 drug metabolites were assembled for testing. Two internal standards were used which monitored different columns in the multi-step analytical separation. Retention reproducibility over a nine month period was 4 p. cent or less for most drugs. The algorithm for matching unknown peaks against the stored library utilized relative retention, lambda maxima, normalized spectral overlays, wavelength ratios and zero-intercepts from the second derivative in a combined forward-reverse search. Most of the drugs which could not be unambiguously identified were sedatives which eluted in the first minutes of the chromatogram. Diasteromers were partially resolved. Repetitive analysis of 200-400 micrograms/l of amphetamine, diphenhydramine, imipramine and morphine were evaluated to establish an absorption cutoff of 12 mAbs, above which at least 95% of peaks were correctly identified. This corresponded to a signal-to-noise ratio of 12 for the scanning UV detector which was evaluated.

Algorithms↗
PubMed1990

Antiproliferative effect of dietary glucarate on the Sprague-Dawley rat mammary gland.

Dietary glucarate has previously been shown to inhibit chemical carcinogen-induced rat mammary tumorigenesis. It is demonstrated in this paper that in the mammary gland of the female Sprague-Dawley rat, feeding glucarate at a dose of 70 mmol/kg AIN76A diet for 2 weeks beginning at 35 days of age, markedly reduces [3H]thymidine labeling. Specific histochemical staining for beta-glucuronidase is used to show that the glucarate diet fed to rats for 2-4 weeks inhibits beta-glucuronidase activity in the mammary gland and has a marked antiproliferative effect on mammary epithelium. Glucarate may inhibit rat mammary carcinogenesis, in part, by changing the proliferative status of the target organ.

Animals↗
PubMed1989

Immunohistochemical demonstration of a mRNA-transport protein in rat liver putative preneoplastic foci.

A 65K protein, known for promoting nucleocytoplasmic mRNA transport in a cell-free system, was previously found in fetal and tumor cells of the rat. The primary objective of this study was to show specificity of immunohistochemical staining for the 65K protein in the livers of rats subjected to a hepatocarcinogenesis protocol. Altered hepatic foci were induced by feeding male weanling Sprague-Dawley rats 2-acetylaminofluorene (AAF) followed by a phenobarbital (PB) diet. It was shown, using polyclonal antibodies produced in rabbits, that the 65K protein was present in the cells of rat liver putative preneoplastic foci, with little or none being detected in the surrounding cells.

Animals↗
PubMed1988

Permeability of placenta to inulin.

Inulin was administered to eight volunteer patients at term gestation over a period of 3 hours before cesarean section. Inulin concentrations were repeatedly measured in maternal plasma, in fetal plasma, and in amniotic fluid at the time of delivery. Total inulin uptake of the conceptus was taken to be the sum of the inulin in the amniotic fluid and in the newborn infant. Amniotic fluid volumes were measured by ultrasound examination, and the distribution volume of inulin in the neonate was assumed to be 180 ml/kg on the basis of animal experiments. The mean permeability was 0.15 microliter/(s.g) placenta. This value and the previously measured permeability for cyanocobalamin delimit a range of molecular weights from 1350 to 5200 daltons. In this range permeability to lipid-insoluble molecules is roughly proportional to the coefficients of free diffusion in water without further discrimination of molecular size by the placental barrier.

Amniotic Fluid↗
PubMed1988

Institutional response to inpatients' threats against the President.

Federal law makes it a crime to threaten the life of the President of the United States. However, psychiatric clinicians have no legal obligation to report all such threats encountered in their practice. In deciding whether to report a threat, they must balance their obligation to protect the President with their duty to uphold a patient's rights to confidentiality and to freedom from self-incrimination. The authors present a case highlighting the issues faced by clinicians in deciding whether to report threats made by psychiatric inpatients and offer guidelines for dealing with such situations. In general, responses to patients' threats against the President should follow the Tarasoff principle, which asserts that clinicians who conclude that a patient presents a danger to another person should take steps to protect that person.

Adult↗
PubMed1987

Perioperative problems in elderly patients.

The number of elderly patients is increasing in all countries. It is estimated that about half of those over 65 will require an operation at some time, most commonly for cataract, prostatic hypertrophy, hernia, gallstones or fractured hip. Whilst overall morbidity and mortality is considerably increased in this age group, it does not appear to result from an increased liability to surgical complications, but rather to the complications of old age itself. The fundamental factor of ageing is a decreased capacity for adaptation, and this applies to virtually all organs and systems. Surgeons and anaesthetists must make allowances for these changes. Most important are cardio-respiratory limitations and altered pharmacokinetics and pharmacodynamics affecting drug action and elimination. These will be discussed in relation to the perioperative period. Once these are understood there should be no hesitation in accepting elderly patients for any form of surgery, provided the likely benefits outweigh the increased risk. Much discomfort in old age can be alleviated by a careful choice of surgery.

Aged↗