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Biomedical subjects

E Roberts

Publications and source records attributed to E Roberts.

At least 145 records · Page 8Linked to original sources
PubMed1990

Prenatal diagnosis of trisomy for the distal two-thirds of the long arm of chromosome 14 (q21----qter).

A de novo case of 'pure' trisomy 14q21----qter is described which was detected at amniocentesis following an abnormal ultrasound scan of a 25-year-old woman. This is apparently the largest distal 14q duplication reported in a case surviving beyond the first trimester. The infant appeared to have an association of clinical abnormalities previously observed in distal 14q trisomy and proximal 14q trisomy/mosaic trisomy 14.

Adult↗
PubMed1989

Multicenter trial of naloxone in Alzheimer's disease.

In a double-blind, placebo-controlled, crossover study of intravenously administered naloxone hydrochloride, 54 subjects with clinically ascertained Alzheimer's disease tested at three university centers showed no significant improvement in neuropsychological performance after 1-mg or 10-mg doses; 15 patients at 1 center were similarly unimproved after receiving 30 mg naloxone (single blind). Findings fail to support claims that naloxone monotherapy ameliorates cognitive impairments of Alzheimer's disease.

Adult↗
PubMed1989

Molecular cloning, nucleotide sequence, and abscisic acid induction of a suberization-associated highly anionic peroxidase.

A highly anionic peroxidase induced in suberizing cells was suggested to be the key enzyme involved in polymerization of phenolic monomers to generate the aromatic matrix of suberin. The enzyme encoded by a potato cDNA was found to be highly homologous to the anionic peroxidase induced in suberizing tomato fruit. A tomato genomic library was screened using the potato anionic peroxidase cDNA and one genomic clone was isolated that contained two tandemly oriented anionic peroxidase genes. These genes were sequenced and were 96% and 87% identical to the mRNA for potato anionic peroxidase. Both genes consist of three exons with the relative positions of their two introns being conserved between the two genes. Primer extension analysis showed that only one of the genes is expressed in the periderm of 3 day wound-healed tomato fruits. Southern blot analyses suggested that there are two copies each of the two highly homologous genes per haploid genome in both potato and tomato. Abscisic acid (ABA) induced the accumulation of the anionic peroxidase transcripts in potato and tomato callus tissues. Northern blots showed that peroxidase mRNA was detectable at 2 days and was maximal at 8 days after transfer of potato callus to solid agar media containing 10(-4) M ABA. The transcripts induced by ABA in both potato and tomato callus were identical in size to those induced in wound-healing potato tuber and tomato fruit. The anionic peroxidase peptide was detected in extracts of potato callus grown on the ABA-containing media by western blot analysis. The results support the suggestion that stimulation of suberization by ABA involves the induction of the highly anionic peroxidase.

Abscisic Acid↗
PubMed1989

Alzheimer's dementia: performance on parallel forms of the dementia assessment battery.

Fifty-four patients with Alzheimer's disease performed on the Dementia Assessment Battery that comprised of finger tapping, forward digit span, naming, verbal memory, visual memory, Token Test, digit cancellation, word-list generation, symbol-digit substitution, and copying geometric designs. Four forms of the battery were administered at weekly intervals. The equivalence of the forms, the relative difficulty of the tests, retest reliability, and factorial composition of the battery are presented. Performance improved with repetition. Impairments in visuo-spatial and verbal abilities were independent of each other. The fragility of the patients' working memory was identified as a main cause for their poor recall. The importance of "component analysis" in individual assessment is illustrated.

Aged↗
PubMed1989

A health promotion program: Staying Healthy After Fifty.

In this article, a description of how a comprehensive health promotion program for older adults was developed, tested with a quasi-experimental study design, and then revised to become a nationwide AARP and Red Cross program is presented. Teaching and learning methods used in the course are described with supporting education and behavioral theory. The course content for instructors, facilitators, and course participants is outlined. The key elements in the preparation of instructors and facilitators are identified. Results of the implementation of the program are given.

Academies and Institutes↗
PubMed1989

Evaluation of the Staying Healthy After Fifty educational program: impact on course participants.

A study to evaluate the impact of a medical self-care program on older adults was conducted. The test group (n = 161) participated in an 11-session educational intervention with training in clinical skills, lifestyle, and the use of health services. The comparison group (n = 164) received no intervention. The test group was assessed pre-intervention, post-intervention, and six months post-intervention and the comparison group was assessed at corresponding intervals. The results indicated that medical self-care instruction produces substantial improvements in health-related knowledge, health skills performance, and health actions. This study produced no evidence, however, that medical self-care instruction has any effect on health status, the utilization of medical care, or other aspects of life quality.

Aged↗
PubMed1989

Hawaii Asian-American response to the Staying Healthy After Fifty program.

A nationwide project conducted by the American Association of Retired Persons, the American Red Cross, and the Dartmouth Institute for Better Health to disseminate a health promotion program for older adults included a study to test its ability to serve different ethnic minorities. This article reports how the Staying Healthy After Fifty Program, designed for the general United States population, was introduced into the State of Hawaii, how it was adapted for use with two Asian-American groups, the Japanese and Filipinos, and on the benefits reported by participants. To determine the appropriateness and effectiveness of the adapted SHAF program, a quasi-experimental design, involving a test group and a comparison group whose members completed questionnaires at three points in time, was used. The results of the data collected from the Hawaiian population were consistent with the results of the general U.S. population skills, health activities, and health care cost skills areas. Participants were very pleased with the course and its quality, as noted in the high ratings of course satisfaction.

Aged↗
PubMed1989

Preventable mortality: indicator or target? Applications in developing countries.

Preventable mortality, empirically defined, is analysed using the standardized mortality ratio for all ages (SMR), the SMR for deaths occurring before age 65, and the ratio of observed and expected years of potential life lost (RYPLL). Mortality data from Argentina and Mexico are used for illustration. To assess progress made, expected deaths are computed using data from the country's own past; to show challenges still ahead, expected deaths are computed using the rates of the United States of America. Comparisons with the past are made for mortality from all causes only; to assess what lies ahead, cause-specific mortality is also looked at. It is shown that for the data at hand the RYPLL is the indicator most sensitive to discrepancies between number of deaths observed and those expected, and that it provides information on inequalities beyond and in addition to that obtained from analysing crude and age-adjusted mortality rates and cause-specific proportional mortality. It is hoped that countries and areas will use these procedures for their own benefit to assess their current health situation against their own past and also against a suitable future reference, to assist them in priority setting and surveillance and evaluation of their health-services system.

Adolescent↗
PubMed1988

Structure-activity studies on inhibition of choline uptake by a mouse brain synaptosomal preparation: basic data.

Over 80 substances were studied for their inhibition of high-affinity uptake of [3H]choline into a mouse brain synaptosomal fraction. Kinetic experiments tested a number of them for competitive behavior. A minimal provisional model for the choline uptake process is envisioned that is consistent with current data and with relevant observations in the literature. There are two hydrophilic anionic sites on the choline transporter that are separated from each other by a cationic hydrophobic domain. Association of choline in a Na+-dependent manner with one or both of the sites is necessary for the transport of choline to take place. The choline binding anionic sites are sufficiently large and/or flexible to allow attachment of cationic moieties larger than choline. The cationic hydrophobic domain of the transporter is flexible, probably tending to planarity. The length of the hydrophobic region between the anionic sites is approximately that of 10 extended methylene groups, and the minimal width is approximated by the distance across the condensed ring system of chlorpromazine. The probability of attachment of the highly hydrophilic choline to its binding sites is increased both by hydrogen-bonding to a proton-acceptor within the anionic sites and by repulsion from the cationic hydrophobic region. A number of substances that potently and competitively inhibit high affinity choline uptake possess quaternary ammonium groups and neutral or negatively charged lipophilic groups. In general, substances in which two quaternary ammonium groups are separated by an appropriately configured hydrophobic group and which can combine with both anionic sites and the hydrophobic region between them are more potent inhibitors than monoquaternary substance with the same or similar groups. However, substances with a single high-affinity quaternary group and an appropriately structured hydrophobic group, e.g. the trimethoxy-3-butynyl quaternary ammonium compounds, possess inhibitory efficacies similar to those shown by the most potent bisquaternaries. The above suggests that further delineation of the characteristics of the structures of the above sites of the transporter could lead to devisal of more potent reversible inhibitors of choline uptake than now are available.

Animals↗
PubMed1988

Dehydroepiandrosterone sulfate improves memory in aging mice.

Middle-aged (18 month old) and old (24 month old) mice showed poorer retention of footshock active avoidance training (FAAT) than young mice (2 month old). Immediate post-training subcutaneous injection of dehydroepiandrosterone sulfate (DHEAS) improved retention of FAAT in middle-aged and old mice to the high levels observed in young mice. DHEAS, a major naturally occurring adrenal steroid that decreases in blood serum with age, could be rate-limiting in achievement of retention of learning.

Aging↗
PubMed1988

Dehydroepiandrosterone and its sulfate enhance memory retention in mice.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), major naturally occurring precursors of both androgenic and estrogenic steroids, were shown in the present study to have convincing memory enhancing effects in mice. Post-training intracerebroventricular (i.c.v.) administration of DHEA in dimethylsulfoxide (2 microliters) prevented the amnesia for footshock active avoidance training (FAAT) caused by the same volume of dimethylsulfoxide alone. DHEAS significantly enhanced retention of FAAT in weakly trained mice whether injected i.c.v. or s.c. immediately post-training or given in the drinking water for a 2-week period. In the latter instance DHEAS was shown to facilitate retention of FAAT without enhancing acquisition. The maximally effective doses were: i.c.v., 162 ng/mouse; s.c., 700 micrograms/mouse; and oral, 1.45 mg/mouse/day. DHEAS administered i.c.v. occluded the amnestic effects of anisomycin (inhibitor of protein synthesis) and scopolamine (muscarinic cholinergic antagonist). There was a time-dependence of the facilitatory effects of post-training i.c.v. administration of DHEAS on retention of FAAT, significant enhancement of retention being observed when it was given either immediately (within 2 min) or at 30 and 60 min after training, but not at 90 or 120 min. DHEAS given i.c.v. also improved retention for step-down passive avoidance. In all instances, dose-dependent inverted U curves were obtained in a manner typical for memory enhancing substances. At a practical level, these experiments open new possibilities for the development of substances that may help in alleviating amnesic disorders in man.

Administration, Oral↗
PubMed1988

Studies on uptake of gamma-aminobutyric acid by mouse brain particles; toward the development of a model.

Several substances were studied for their effect on enhancement and/or inhibition of uptake of GABA into a mouse brain microsomal fraction (P3) at pH 7.3 in the presence and absence of buffer. These were diverse: Na+, K+, NH4+, Hg2+, Cl-, and HCO3-; beta-guanidinopropionic and L-2,3-diaminopropionic acids and 1,2-diaminoethane; pyridine and several methylated pyridines; chlorpromazine and ketamine; and melittin. Kinetic experiments tested these substances for competition with GABA and Na+. Assuming the GABA transporter to consist of a GABA recognition entity and a Na+- and Cl-dependent protein required for its activity, a minimal provisional model for the GABA uptake process is proposed that is consistent with all current data and with relevant observations in the literature. It accounts for the activational effects of proton removal on GABA uptake, the stoichiometry of 2 Na+ and 1 Cl- associated with uptake of one GABA molecule, and the types of inhibition of uptake shown by the substances listed above. Factors are considered that may be necessary to maintain the transporter in a GABA-receptive configuration and that allow it the freedom of movement to undergo the structural variations necessary for the transport process to take place at rates that may be regulated by environmental factors.

Animals↗
PubMed1988

Maternal cell contamination in chorionic villus samples assessed by direct preparations and three different culture methods.

Presumptive maternal cell contamination (MCC) was monitored in identified male cases during cytogenetic comparison of direct techniques and three different culture regimens from 140 thoroughly dissected chorionic villus samples. Of the 66 identified male cases, 11 (16.7 per cent) showed MCC, the mean number of cells examined per case being 8.2 (direct) and 14.5 (cultures); in the direct preparations only one of a total of 457 cells examined was female, while preparations from cultures revealed MCC in 11 cases. Four of these had MCC in more than one culture regime and four had only a single female cell. The results showed that (1) dependence on the culture system alone would have given a diagnosis based on maternal cells in one (1.5 per cent) male case, thus underlining the danger of this approach (a similar undetected rate of misdiagnosis being expected in the female cases) and (2) MCC was significantly lower in cultures grown in Chang medium as compared with the other two regimes, McCoy's 5A + 15 per cent fetal calf serum and 1 per cent Ultroser G, and McCoy's 5A + 25 per cent fetal calf serum, the latter expressing the highest level of MCC.

Chorionic Villi Sampling↗
PubMed1988

Stage-selective inhibition of rodent malaria by cyclosporine.

The relative susceptibility of different developmental stages of Plasmodium berghei to cyclosporine was investigated in vivo. Within 12 h of receiving a single 25-mg/kg (body weight) dose of cyclosporine, mice with patent P. berghei infections uniformly exhibited a rapid fall in asexual parasite stages. Initially, ring forms and mature schizonts disappeared. Subsequently, trophozoites disappeared between 21 and 24 h, whereas gametocytes persisted for 36 h. In contrast, when cyclosporine was administered to mice 1 day before inoculation (100 mg/kg) with P. berghei sporozoites and for 2 consecutive days after inoculation (25 mg/kg), infections developed normally. When mice with patent infections were placed on prolonged cyclosporine therapy (25 mg/kg per day), parasitemia initially disappeared but often recrudesced. Recrudescent parasites were frequently resistant to cyclosporine (Csr). The Csr phenotype remained stable after serial passage of parasites in mice and after transmission through Anopheles stephensi mosquitoes, in which the capacity to produce oocysts was reduced. When infections of untreated mice were initiated with equal numbers of Csr and cyclosporine-susceptible (Css) parasites and then carried through two serial cycles of mosquito-to-mouse transmission without cyclosporine treatment, the Csr phenotype was lost. The results indicate that cyclosporine selectively inhibits asexual blood stages of P. berghei and favors the emergence of Csr parasites with diminished infectivity for mosquitoes.

Animals↗