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Biomedical subjects

E Smith

Publications and source records attributed to E Smith.

At least 289 records · Page 16Linked to original sources
PubMed1988

An in vitro study comparing the cytotoxicity of three platinum complexes with regard to the effect of thiol depletion.

The cytotoxicity of three platinum complexes, cis-diamminedichloroplatinum(II) (cis-platin), cis-dichloro-trans-dihydroxy-cis-bis (isopropylamine) platinum(IV), (CHIP) and diammine (1, 1-cyclobutane-dicarboxylato) platinum(II) (carboplatin) on Chinese Hamster ovary (CHO) and mouse sarcoma RIF-1 cells cultured in vitro has been compared. The tumour cell line was much more sensitive to the cytotoxic action of the three agents compared to the CHO cell line. CHIP and carboplatin gave similar dose-response curves, both being much less toxic than cis-platin. The effect of thiol modification on platinum toxicity was also investigated. Substantial reduction in the intracellular non-protein sulphydryl content markedly enhanced the cytotoxicity of CHIP but had much less effect on carboplatin and cis-platin. Thiol depletion by diethylmaleate had a negligible effect on cis-platin toxicity.

Animals↗
PubMed1988

Factors associated with age-related macular degeneration. An analysis of data from the first National Health and Nutrition Examination Survey.

Data from the first National Health and Nutrition Examination Survey collected between 1971 and 1972 were used to determine what factors are associated with the prevalence of age-related macular degeneration. The study was limited to those who were at least 45 years old at the time of the ophthalmology examination. Stratified analysis, adjusting for age, showed that education, systolic blood pressure, past history of hypertension, cerebrovascular disease, and refractive error were all associated with macular degeneration. With the exception of education, these factors remained statistically significant when simultaneously entered into a logistic regression model. The frequency of consumption of fruits and vegetables rich in vitamins A and C suggested a negative association with the prevalence of macular degeneration after stratified adjustment for age. In a logistic regression analysis, adjusting for demographic and medical factors, the inverse association of vitamin C with age-related macular degeneration was no longer present. The frequency of consumption of fruits and vegetables rich in vitamin A remained negatively correlated with age-related macular degeneration even after adjustment for demographic and medical factors.

Age Factors↗
PubMed1988

Synergistic cytotoxicity of iodinated contrast agents and x-radiation.

The synergistic cytotoxicity of iodinated radiologic contrast agents and x-radiation is discussed. Experiments are described illustrating the phenomenon and lending support to the view that it is mediated by energetic photoelectrons. Some of its practical implications are indicated.

Animals↗
PubMed1988

Characterization of an antigenically related family of cell-type specific proteins implicated in slug migration in Dictyostelium discoideum.

The monoclonal antibody MUD50 recognizes a group of developmentally regulated proteins, which are almost exclusively expressed by prespore cells in developing aggregates of Dictyostelium discoideum. Some of these antigens are integrally associated with the cell membrane, as assessed by physical and detergent-fractionation procedures. The MUD50-reactive proteins are glycosylated and some are phosphorylated. Post-translational modification is the common antigenic feature that is recognized by the MUD50 antibody in these cell-type-specific proteins. A glycosylation-defective mutant, DL118, (modB) does not express the MUD50 epitope, but does express the MUD52 epitope, which is found on a different group of glycoproteins. Therefore, we conclude that MUD50 recognizes a particular carbohydrate epitope on a restricted group of proteins. These proteins are structurally diverse, but are apparently involved in the maintenance of structure and movement of the multicellular D. discoideum slug.

Antibodies, Monoclonal↗
PubMed1988

Structural characterization of Dictyostelium discoideum prespore-specific gene D19 and of its product, cell surface glycoprotein PsA.

The Dictyostelium discoideum cell surface antigen PsA is a glycoprotein which first appears in the multicellular stage soon after tip formation and is selectively expressed on prespore cells. The D19 gene encodes an mRNA sequence which is highly enriched in prespore over prestalk cells in the slug stage. We have determined 81 amino acid residues of N-terminal sequence from immunoaffinity-purified PsA protein and shown this sequence to be identical to the predicted sequence of the D19 gene. There are several short repeat elements close to the C terminus, and unequal crossing-over within these is proposed to account for the size polymorphism observed in PsA protein isolated from different D. discoideum strains. The repeats are proline rich and show similarity to the C-terminal region of the D. discoideum cell adhesion molecule, contact sites A. The extreme C terminus, which is also homologous to contact sites A, is characteristic of proteins attached to the plasma membrane via a glycosyl-phosphatidylinositol link. We have marked the PsA gene by insertion of an oligonucleotide encoding an epitope of the human c-myc protein. A construct containing this gene and 990 base pairs of 5'-flanking region directed correct temporal and spatial mRNA accumulation. We found the marked PsA protein, detected with the human c-myc antibody, to be correctly localized on the surface of cells.

Amino Acid Sequence↗
PubMed1988

Association of the slow feathering (K) and an endogenous viral (ev21) gene on the Z chromosome of chickens.

A dominant sex-linked gene, K, regulates slow feathering (SF), whereas a recessive allele, k+, determines rapid feathering (RF) in chickens. This trait provides a convenient and inexpensive approach to gender identification of White Leghorn (WL) chicks at hatch, i.e., in a sex-linked mating using k+/k+ males mated with K/- females, the K/k+ male chicks are SF, and the k+/- females are RF. However, in many WL strains, female progeny of SF dams produce fewer eggs and have higher mortality than progeny of RF dams. This loss in productivity has been attributed to higher infection and shedding rates for leukosis viruses (ALV) in SF than in RF dam lines. Because infectious endogenous viruses (EV) can induce immunological tolerance to ALV, we examined the expression and distribution of ev genes in SF and RF siblings from heterozygous K/k+ sires and k+/- dams. Infectious ALV and EV were detected by cocultivation of frozen heparinized blood cells on selected chick embryo fibroblasts and culture supernatants were tested for viral antigen by enzyme-linked immunosorbent assay tests. Specific ev genes were identified as restriction fragment length polymorphisms after hybridization with a recombinant plasmid containing the complete genome of a Rous-associated virus. It was concluded that ev21 and K genes are tightly linked because, in different WL crosses, all SF chicks inherited ev21 but RF siblings uniformly lacked ev21. Alternatively, the K gene in WL may be a mutation resulting from the insertion of ev21 in the k+ gene. The SF chicks which harbor ev21 expressed infectious EV21; evidence that EV21 may influence susceptibility to ALV is presented.

Animals↗
PubMed1988

Patients with rheumatoid arthritis at high risk for noncompliance with salicylate treatment regimens.

Recent studies indicate the adherence of many patients with rheumatoid arthritis (RA) to their treatment regimens is poor. Management of this problem depends on identification of noncompliant patients, followed by interventions to increase their level of adherence. In this study, 63 patients with RA receiving salicylate drugs completed a questionnaire during an outpatient visit. The questionnaire contained items believed to be predictive of future compliance, including patient self-predictions regarding future compliance, ratings of behavior in similar situations and barriers to compliance, such as ease of transportation to the clinic. Compliance was estimated via a salicylate assay that was taken during a subsequent outpatient appointment. Multivariate analyses of our data revealed that significant predictions could be made regarding future compliance, with 75% of the noncompliant patients correctly identified. Variables contributing significantly included behavioral self-predictions and a measure of current behavior in similar situations, as assessed by a salicylate assay that was collected during the 1st outpatient visit.

Arthritis, Rheumatoid↗
PubMed1988

Antidepressant analgesia in rheumatoid arthritis.

Forty-seven patients with definite rheumatoid arthritis (RA) were treated in a 32 week, double blind, crossover trial of amitriptyline, desipramine, trazodone, and placebo. All drug regimens produced significant changes on pain measures relative to baseline, but only amitriptyline exceeded placebo. Amitriptyline was associated with a significant reduction in the number of painful/tender joints. Our study supports the efficacy of a moderate dose of amitriptyline as an adjunct drug for the treatment of pain in both depressed and nondepressed patients with RA.

Aged↗
PubMed1988

Concurrent liquid-chromatographic assay of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in plasma, with tocopherol acetate as internal standard.

A method is described for simultaneously determining retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in 0.25 mL of plasma. Plasma mixed with sodium dodecyl sulfate is deproteinized with ethanol containing tocopherol acetate, then extracted with heptane. The evaporated organic layer is reconstituted with mobile phase (methanol/acetonitrile/chloroform, 47/47/6 by vol) and injected onto a 100 x 4.6 mm 3-micron column of Spherisorb ODS-2 (LKB) at 1.5 mL/min. The alpha- and beta-carotenes are well resolved during the 6.5-min run. Retinol is monitored at 325 nm, the tocopherols at 292 nm, and the carotenoids at 450 nm. Extraction of concentrations as great as 135 mumol/L is complete. Intrabatch CVs were 1.7%, 2.3%, 4.1%, 10.4%, 6.4%, and 3.6% for retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin, respectively. Interbatch CVs for measurements on 30 occasions over 11 weeks were about 10% for all components except alpha-tocopherol (5.3%). Results agree well with those for retinol, alpha-tocopherol, and beta-carotene in quality-control samples.

Carotenoids↗
PubMed1988

Pain in rheumatoid arthritis: relationship to demographic, medical, and psychological factors.

Our purpose was to investigate the relationship among demographic, medical, and psychological factors and self-reported pain in 135 patients with classic or definite rheumatoid arthritis (RA). Patients were examined using the systemic index, articular index, McGill Pain Questionnaire, Symptom Checklist-90-R, and a pain visual analogue scale. Multiple regression analyses found no significant relationships between pain and the medical variables. However, age, income, and selected psychological variables were significantly correlated with pain reports. The greatest pain management challenge occurred in patients who were middle-aged, living on limited incomes, and experiencing major stresses in everyday life. These high risk pain patients were also worry-prone and felt isolated and lacking in social support. Attention to these related psychosocial problems is recommended as an important pain management strategy in RA.

Arthritis, Rheumatoid↗
PubMed1988

Depression in rheumatoid arthritis.

Operationalized diagnostic criteria for depression were used to assess 137 (76% male, 24% female) patients with rheumatoid arthritis (RA). Forty-two percent met criteria for some form of depression. Discriminant function analysis revealed a significant relationship between the presence or history of depression and higher levels of pain, but not between current depression and common indicators of RA activity or severity. These results suggest that depression is a frequent disorder among persons with RA. The importance of patient appraisal of disease and assessment of repeated depressive episodes is discussed. Attention to specific interventions for depression in conjunction with the treatment of the RA is suggested.

Arthritis, Rheumatoid↗
PubMed1987

Resolution of enantiomeric amides on a cellulose tribenzoate chiral stationary phase. Mobile phase modifier effects on retention and stereo-selectivity.

The effect of the steric structure and concentration of the mobile phase modifier on the retention (kappa') and stereoselectivity (alpha) of a series of enantiomeric amides has been investigated. The amides were chromatographed on a commercially available cellulose tribenzoate chiral stationary phase (CSP) using mobile phases composed of hexane and two homologous series of alcohols: methanol, ethanol, 1-propanol and 2-propanol, 2-butanol, 2-pentanol, 2-hexanol. The results of the study indicate that the alcoholic mobile phase modifiers compete with the solutes for achiral and chiral binding sites and that the steric bulk around the hydroxyl moiety of the modifier plays a role in this competition. Increased steric bulk tends to result in increased kappa' and alpha. However, the results also suggest that the effect of the alcoholic mobile phase modifiers on stereoselectivity may also be due to binding to achiral sites near or at the chiral cavities of the CSP which alters the steric environment of these cavities.

Alcohols↗
PubMed1987

Nonspecific dementia, cortical blindness, and Congophilic angiopathy. A clinicopathological report.

Postmortem examination of an elderly male with cortical blindness and features of both cortical and subcortical dementia revealed extensive neuronal dropout most marked in the occipital cortex, moderate gliosis, rare neuritic plaques, no neurofibrillary tangles, and extensive Congophilic angiopathy. The unprecedented association of Congophilic angiopathy with nonspecific dementia provides further support for the concept that Congophilic angiopathy is usually a nonspecific manifestation of neuronal degeneration and of little clinical significance except when it results in intracerebral hemorrhage.

Aged↗
PubMed1987

Bradyphrenia in Parkinson's disease and psychomotor retardation in depressive illness. An experimental study.

Thirty newly diagnosed patients with Parkinson's disease and 30 patients with primary depressive illness showed slowing of response on a computerized digit symbol substitution test when compared with 30 matched normal control subjects. Significant slowing was related, in the parkinsonian patients, to structural brain disorder and affective impairment and, in the depressed patients, to motor impairment. A second computerized test, cognitively simpler but requiring the same motor response, was also administered to each subject. Both cognitive and motor slowing seemed to contribute to slowing of response in the digit symbol test in both parkinsonian and depressed patients. The tests were repeated after about six months in 12 subjects from each group. The parkinsonian patients, on dopaminergic treatment, showed neither significant change in motor or affective impairment, nor improvement in response time for the digit symbol test, but change in response time was related to change in depression rating. The depressed patients, on conventional treatment, showed significant improvement in both affective and motor impairment and improvement in response time for the digit symbol test, due to improvement in cognitive slowing. It is proposed that bradyphrenia in Parkinson's disease and psychomotor retardation in depressive illness are closely related, and that impairment of dopaminergic systems may be involved in both.

Brain↗