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Biomedical subjects

A Dean

Publications and source records attributed to A Dean.

At least 55 records · Page 3Linked to original sources
PubMed1994

The palliative effects of octreotide in malignant disease.

Octreotide is a synthetic analogue of somatostatin with a longer half-life than the native peptide. It has been used extensively in a variety of clinical settings for some years. More recently, its uses in malignant disease processes have been studied and it is proving to be an excellent addition to the palliative care pharmacy. We look at the current uses of octreotide for the palliation of malignant disease with particular emphasis on inoperable malignant bowel obstruction. Octreotide may palliate nausea and vomiting in this distressing condition when other therapies fail. Octreotide may also control severe diarrhoea and help in the closure of fistulae from benign and malignant conditions. It has unique analgesic properties. Radio-labelled isotopes of octreotide may be used to image some tumours. Recently, it has also shown potential in anti-cancer treatment.

Humans↗
PubMed1993

Structure of isocitrate dehydrogenase with isocitrate, nicotinamide adenine dinucleotide phosphate, and calcium at 2.5-A resolution: a pseudo-Michaelis ternary complex.

The structure of isocitrate dehydrogenase (IDH) with a bound complex of isocitrate, NADP+, and Ca2+ was solved at 2.5-A resolution and compared by difference mapping against previously determined enzymatic complexes. Calcium replaces magnesium in the binding of metal-substrate chelate complex, resulting in a substantially reduced turnover rate. The structure shows the following: (i) A complete, structurally ordered ternary complex (enzyme, isocitrate, NADP+, and Ca2+) is observed in the active site, with the nicotinamide ring of NADP+ exhibiting a specific salt bridge with isocitrate. The binding of the cofactor nicotinamide ring is dependent on this interaction. (ii) Isocitrate is bound by the enzyme with the same interactions as those found for the magnesium/substrate binary complex, but the entire molecule is shifted in the active site by approximately 1 A in order to accommodate the larger metal species and to interact with the nicotinamide ring. The distances from isocitrate to the bound calcium are substantially longer than those previously found with magnesium. (iii) NADP in the Escherichia coli IDH has a novel binding site and conformation as compared to previously solved dehydrogenases. (iv) The orientation and interactions of the nicotinamide ring with the substrate are consistent with the stereospecificity of the enzyme-catalyzed reaction.

Binding Sites↗
PubMed1993

Enhancer-dependent transcription of the epsilon-globin promoter requires promoter-bound GATA-1 and enhancer-bound AP-1/NF-E2.

We analyzed epsilon-globin transcription in erythroid cells and in erythroid extracts to determine the requirements for enhancer-dependent expression of this gene. Mutations that abolished GATA-1 binding at a single position in the promoter prevented interaction with enhancers, whereas elimination of a second more distal promoter GATA-1 site had no effect. Deletion or mutation of the GATA-1 sites in either the human beta-globin locus control region DNase-hypersensitive site II enhancer or the chicken beta A/epsilon-globin enhancer did not diminish the ability of the enhancers to interact with the promoter. In contrast, mutation of the AP-1/NF-E2 sites in these enhancers resulted in elimination of enhancement. In vitro transcription of these constructs was promoter dependent and was not sensitive to abolition of GATA-1 binding in the promoter, consistent with the role of GATA-1 solely as a mediator of the enhancer effect. Thus, GATA-1 regulates the response of the epsilon-globin gene to enhancers through a specific site in the promoter and requires enhancer AP-1/NF-E2 binding to transduce the enhancer effect on transcription.

Base Sequence↗
PubMed1993

Social support from friends and psychological distress among elderly persons: moderator effects of age.

In this study, the relationships among age, sex, friend support, and psychological distress are examined among elderly persons. Structural equation modeling and a longitudinal design are used to examine direct, indirect, and moderator (interaction) effects over a 22-month interval. Findings suggest that different causal processes operate among persons over the age of 70 (old-old) and those 50 to 70 years (young-old); the cross-lagged effects of friend support on distress and of distress on friend support are only observed in the older group. Compared to the young-old, the old-old receive less friend support at time 2 (T2) if they experienced psychological distress at time 1 (T1), and the old-old are more distressed at T2 if they received low levels of support at T1. As a result of this age interaction, the total effects of sex on distress and support at T2 are twice as large in the sample of old-old persons as in the sample of young-old persons. Such findings suggest that the old-old in general and old-old men in particular are especially vulnerable to psychological distress when losing friend support, and to lose friend support when experiencing psychological distress. Implications of these and other findings are discussed.

Age Factors↗
PubMed1992

Sarcomas of the head and neck.

Fourteen cases of sarcomas involving the head and neck over a period of 15 years were reviewed. The male to female ratio was 3.5:1. Mean age of occurrence was 33.4 years, with a range of 5-84 years. Soft tissue was the site of origin in three cases, maxilla in four and mandible in seven patients. Radical surgery with resection of adequate disease-free margins was the most effective mode of treatment. Radiotherapy and chemotherapy was used in selected cases. Recurrence occurred in 42.9% of patients, and was the main cause of death. Three patients (21.4%) developed distant metastases. The actuarial 2-year and 5-year survivals of the 14 patients assessed were 64% and 56% respectively.

Adolescent↗
PubMed1992

Continuing your education ... with CATS.

MIKE McMANUS and ANNE DEAN discuss the credit accumulation and transfer scheme (CATS) and consider many of the common questions regarding the system: how to accredit current professional qualifications; use of credited learning, and potential continuing education pathways open to health visitors. Finally, the authors discuss the validity of such awards.

Education, Nursing, Baccalaureate↗
PubMed1992

Comparison of frequencies of suicidal tendencies among patients receiving fluoxetine, lofepramine, mianserin, or trazodone.

To evaluate whether fluoxetine causes an important increased risk of suicidal behavior, we compared the frequency of attempted suicide, suicidal ideation, and aggressive behavior in persons who received fluoxetine, lofepramine, mianserin, and trazodone, based on information available on general practitioners' computers provided by Value Added Medical Products, Ltd. The frequency of these events was higher in fluoxetine users in the year prior to first treatment than in users of the other three antidepressants. The frequency of these events in the 90 days after the study drug was started was similar for the users of all four drugs. These data indicate that fluoxetine does not directly cause suicidal behavior at a substantially higher frequency than do lofepramine, mianserin, and trazodone.

Adolescent↗
PubMed1991

How common are epileptic seizures in old age?

A large primary-care computerized database was searched to determine the incidence and prevalence of epilepsy and epileptic seizures in old age compared with the general population. The prevalence of subjects with a diagnosis of epileptic seizures was higher in older age groups: 10.9/1000 for sexagenarians, 12.0 for septuagenarians and 13.1 for those over 80, compared with 9.0/1000 in the overall population. The overall prevalence in subjects aged over 60 was 11.8. Annual incidence rose even more sharply in old age: 76/100,000 for sexagenarians, 147 for septuagenarians, and 159 for those over 80, compared with an overall population incidence of 69/100,000. The overall incidence in subjects over 60 was 117. Of incident cases requiring treatment, 35.5% were over 60 years old. Our findings are in keeping with other recent epidemiological studies and in part reflect the age-associated increase in the prevalence of cerebrovascular disease. They have implications for the organization of services for elderly people, for the education of general practitioners and hospital doctors and for directing epilepsy research.

Aged↗
PubMed1991

The recognition and non-recognition of problem-solving stages in nursing practice.

A requirement for high-quality individualized nursing care is that nurses must recognize and attempt to solve patients' health problems. In this study, it was decided to investigate problem solving using a model similar to the nursing process derived from the general literature. Insight into nurses' perceptions and understanding of problem solving was gained by interviewing 116 nurses using vignettes of clinical problem solving. Data analysis revealed that many informants failed to discuss some problem-solving stages, in particular planning and evaluation. Conversely, problem assessment and implementation attracted more comment. The implications for these variations in nurses' problem-solving behaviour are examined in relation to contemporary nursing issues.

Humans↗
PubMed1991

Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter.

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.

Animals↗
PubMed1991

[Pilomatrix carcinoma. A new case].

We present a new case of Pilomatrix Carcinoma after having review the 22 cases previously published. The tumor arisen in a 74 years old male, in the left preauricular region. The lesion was excised with wide margins. A year after there is not any evidence of recurrence or metastases.

Aged↗
PubMed1990

Yeast alpha 2 repressor positions nucleosomes in TRP1/ARS1 chromatin.

The yeast alpha 2 repressor suppresses expression of a-mating-type-specific genes in haploid alpha and diploid a/alpha cell types. We inserted the alpha 2-binding site into the multicopy TRP1/ARS1 yeast plasmid and examined the effects of alpha 2 on the chromatin structure of the derivative plasmids in alpha cells, and a/alpha cells. Whereas no effect on nucleosome position was observed in a cells, nucleosomes were precisely and stably positioned over sequences flanking the alpha 2 operator in alpha and a/alpha cells. In addition, when the alpha 2 operator was located upstream of the TRP1 gene, an extended array of positioned nucleosomes was formed in alpha cells and a/alpha cells, with formation of a nucleosome not present in a cells, and TRP1 mRNA production was substantially reduced. These data indicate that alpha 2 causes a positioning of nucleosomes over sequences proximal to its operator in TRP1/ARS1 chromatin and suggest that changes in chromatin structure may be related to alpha 2 repression of cell-type-specific genes.

Gene Expression Regulation, Fungal↗