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Biomedical subjects

B Davies

Publications and source records attributed to B Davies.

At least 127 records · Page 7Linked to original sources
PubMed1994

Changes over time: a study of family bereavement following childhood cancer.

A longitudinal follow-up study which examined changes in 48 families over time (7-9 years) following a death of a child with cancer was conducted. The loss of a child required individual reorganization and adjustments within the family system. Changes in marital status and/or the addition of other children required adjustment in the relationships of family members. Some of the changes were developmental in nature while others, according to the informants, were directly related to the death of the child.

Adaptation, Psychological↗
PubMed1993

Levels of matrix metalloproteases in bladder cancer correlate with tumor grade and invasion.

We have used quantitative zymography to measure levels of the type IV collagenases matrix metalloproteinase (MMP)-9 and MMP-2 in 42 biopsies of transitional cell carcinoma and in 7 biopsies of normal bladder. Mean levels of MMP-9 were significantly higher in tumor compared with normal samples (P = 0.08). Levels of MMP-9 and active MMP-2 increased with tumor grade (test for trend, P = 0.002 and P = 0.05, respectively). Levels of MMP-9 and activated MMP-2 were also higher in invasive tumors than in superficial ones (P = 0.001 and P = 0.008, respectively). In situ hybridization studies showed that the mRNAs for both MMP-2 and MMP-9 were located chiefly in the stroma rather than epithelial tumor cells and were concentrated at the interface between the two tissues.

Carcinoma, Transitional Cell↗
PubMed1993

A synthetic matrix metalloproteinase inhibitor decreases tumor burden and prolongs survival of mice bearing human ovarian carcinoma xenografts.

We have examined the effect of a synthetic low-molecular-weight matrix metalloproteinase inhibitor, [4-(N-hydroxyamino)-2R-isobutyl-3S- (thiopen-2-ylthiomethyl)-succinyl]-L-phenylalanine-N-meth yla mide (BB-94), on human ovarian carcinoma xenografts growing in nude mice. The xenografts grew as thick intraperitoneal mucinous ascites containing free-floating tumor cell clumps. The ascites increased in volume, causing death approximately 3 weeks after introduction. Treatment with BB-94 caused resolution of ascitic disease. Tumor burden was dramatically reduced, and survival increased 5-6-fold. The increase in survival was dose dependent. The effects observed with BB-94 appeared to be due to its matrix metalloproteinase inhibiting effects, inasmuch as its inactive diastereoisomer had no effect on tumor biology. Following treatment with BB-94, free-floating clumps of tumor cells became surrounded by a capsule of host cells. These clumps of tumor cells typically formed one small (approximately 8 mm) avascular tumor of bright white appearance loosely attached to fat in the peritoneum. Tumor cells within these capsules often appeared to be necrotic. Gel substrate analysis demonstrated that activated Mr 92,000 type IV collagenase was present in the xenografts. We propose that inhibition of this enzyme causes the transition of ascites to solid tumors, concomitantly slowing tumor cell growth and allowing the development of tumor stroma.

Aged↗
PubMed1993

The structure of the human intron-containing S8 ribosomal protein gene and determination of its chromosomal location at 1p32-p34.1.

The intron-containing gene encoding human ribosomal protein S8 (RPS8) has been cloned and characterized, and its chromosomal position determined. Using a PCR-based cloning strategy, we have isolated the intron-containing gene in the presence of its many processed pseudogenes and determined the DNA sequence of the entire gene and its upstream and downstream flanking regions. The human RPS8 gene is 3161 bp in length and comprises six exons. Despite lacking a consensus TATA box, primer extension analysis indicates that the start of transcription is precisely located at a C residue within an 11-bp oligopyrimidine tract. The first exon, which contains the ATG start codon, is just 27 bp in length. The DNA sequence 5' to the RPS8 gene and within the first exon and intron shows several features of a CpG island. A combination of Southern blotting, PCR, and fluorescence in situ hybridization analyses has enabled the chromosomal location of the human RPS8 gene to be determined as 1p32-p34.1.

Base Sequence↗
PubMed1993

Sibling bereavement: research-based guidelines for nurses.

Despite the marked improvement in the treatment of childhood cancer in recent decades, there are children who die, leaving behind a legacy of grief for all who knew them, including their siblings. Nurses can play a significant role in facilitating healthy grieving for these surviving children. The results of several studies pertaining to sibling bereavement after the death of a child from cancer provide guidelines for clinicians.

Attitude to Death↗
PubMed1993

Activity of type IV collagenases in benign and malignant breast disease.

Using zymography and computer assisted image analysis, we have measured the levels of type IV collagenases in biopsies from normal breast, and benign and malignant breast disease. The 92 kDa form was present in three of 11 cases of normal/benign disease, three of nine grade I tumours, four of 12 grade II tumours, but 11 of 11 grade III tumours. Mean levels were higher in grade III tumours (P < 0.0001). When the levels of 72 kDa collagenase and its active 62 kDa form were considered together, there was no difference between the benign and malignant cases (P = 0.55), but the amount of active enzyme, considered as a proportion of the 62 + 72 kDa forms, was significantly higher in malignant disease (P = 0.003). There was also a trend towards a higher proportion of active enzyme with increasing tumour grade (P < 0.0001). In situ hybridisation and immunohistochemistry studies showed that that mRNA and protein for the 92 kDa enzyme was primarily found in the tumour stroma. mRNA for the 72 kDa enzyme was also found in stromal areas. This study demonstrates a clear relationship between production of Type IV collagenases and malignant breast disease. Inhibitors of these enzymes may be of value in preventing metastatic disease.

Breast↗
PubMed1993

Restoration of occupational capacity in post-cardiac patients.

Employees returning to work after injury and illness have typically been offered an 'all or nothing' approach to rehabilitation. Dr Bruce Davies questions this attitude and argues for improved policies to facilitate a more effective return to work for post-cardiac patients.

Exercise Therapy↗
PubMed1993

An exploration of nursing disillusionment.

A model of supportive care developed in prior research, combined with ethical theory, is used as a framework for analyzing some of the current problems facing the nursing profession. The authors argue that a central cause of nursing disillusion is dissonance between personal values rooted in an ethic of caring and a health care system that rewards technological competence above human values.

Burnout, Professional↗
PubMed1993

Survey of nursing research programs in children's hospitals.

Available published literature describing successfully implemented research programs is relatively limited, particularly within children's hospitals. In order to determine the status of research program development within children's hospitals, a mailed survey was sent to 108 free-standing children's hospitals in the United States and Canada. The questionnaire was comprised of questions pertaining to five general sections: (a) institutional demographics; (b) organizational structure for research; (c) research activities; (d) relationship to other agency research; and (e) demographic characteristics of the individual completing the survey. Findings indicated that nursing research within children's hospitals is in an early development state, but that it is recognized as a necessary and credible component of nursing. Differences were noted between the groups of hospitals with the most research activity and those with no research activity. Hospitals were in various stages of research development, a sequential process characterized by a sequential pattern comprised of two phases.

Canada↗
PubMed1992

Chemiluminescence of human bloodstream monocytes and neutrophils: an unusual oxidant(s) generated by monocytes during the respiratory burst.

Maximal rates of O2- and H2O2 production by human bloodstream monocytes activated during the respiratory burst by phorbol ester were only about 10% of those of neutrophils. Furthermore, monocytes possess only about 5% of the myeloperoxidase activity of neutrophils and so can only produce low levels of HOCl and related compounds. These combined reductions in O2- generating ability and lower myeloperoxidase levels result in low levels of luminol chemiluminescence stimulated during the respiratory burst of monocytes. However, although monocytes generate much lower levels of O2- and H2O2 than neutrophils, these cells produce comparable rates of PMA-stimulated lucigenin chemiluminescence. Hence, this assay does not accurately reflect the production of either of these two oxidants by activated phagocytes, and further lucigenin must react with some other oxidant(s) via a process which leads to photon emission. This oxidant(s) is not O2-, H2O2, .OH, 1O2 or NO, but is derived from O2- generated during the respiratory burst and is generated in greater quantities by activated monocytes compared with neutrophils. Thus, lucigenin chemiluminescence is an indirect measure of superoxide release.

Acridines↗
PubMed1992

The mapping of seven intron-containing ribosomal protein genes shows they are unlinked in the human genome.

Mammalian ribosomal protein (rp) genes are members of multigene families which are composed predominantly of multiple processed pseudogenes and one functional intron-containing gene. The presence of multiple pseudogenes has hampered the isolation and study of the functional rp genes. We have recently developed a polymerase chain reaction (PCR)-based strategy for the detection of intron-containing genes in the presence of multiple pseudogenes (B. Davies, S. Feo, E. Heard, and M. Fried, 1989, Proc. Natl. Acad. Sci. USA 86: 6691-6695). We have used this technique to identify the intron-containing PCR products of seven human rp genes (rpL19, rpL30, rpL35a, rpL36a, rpS6, rpS11, rpS17) and to map their chromosomal locations. No linkage was found between any of these seven rp genes nor was linkage found to the three other rp genes previously mapped. The wide distribution of the rp genes throughout the human genome strongly suggests that the coordinate regulation of the expression of mammalian ribosomal proteins in response to the cell's varying requirements for protein synthesis is not a result of cis activation of chromosomal regions but is mediated by trans-acting factors.

Blotting, Southern↗
PubMed1992

Interactions between human monocytes and tumour cells. Monocytes can either enhance or inhibit the growth and survival of K562 cells.

Human bloodstream monocytes can kill cultured tumour cells (K562), as assessed by specific release of 51Cr from the targets and by inhibition of 3H-thymidine incorporation. Confluent monolayers of monocytes were required for maximal cytotoxicity, and the density of the K562 cells was also an important factor. For example, when K562 cells were seeded at high cell densities, they were killed during incubation with monocytes, but when seeded at low cell densities their growth and survival was enhanced during culture with monocytes. The factor(s) which promoted the survival and division of low density K562 cultures was endogenously secreted from monocytes as it was present in monocyte-conditioned medium, whereas the cytotoxic factor(s) were only expressed during co-culture of monocytes with K562 cells. Conditioned medium from HL 60, U-937, HeLa and K562 could also enhance the growth and survival of low density K562 cultures, and a similar effect was also observed upon the addition of catalase and superoxide dismutase to such cultures. Thus, the monocyte:target ratio is important in determining whether monocytes exhibit cytotoxic or growth-promoting effects and hence tumour-derived or monocyte-derived reactive oxidant species may play a role in tumour cell cycle regulation.

Catalase↗
PubMed1992

Do patients like day case cataract surgery?

One hundred and fifty consecutive questionnaires following day case cataract surgery showed that 87% of the patients would choose day surgery again. The questionnaires were directed at the patients' attitudes to day surgery for their cataracts. There was overwhelming acceptance of the travelling and inconvenience involved.

Aged↗
PubMed1992

Electrosurgery in restorative dentistry: 1. Theory.

Electrosurgery techniques have been used in dentistry as an aid to soft tissue management for nearly 60 years. However, it was not until the late 1960s that the principles of electrosurgery were understood and improved equipment became available. Part 1 of this two-part series covers the theory behind using this technique. Part 2 will discuss the clinical applications.

Dentistry, Operative↗
PubMed1992

Electrosurgery in restorative Dentistry: 2. Clinical applications.

Electrosurgery techniques have been used in dentistry as an aid to soft tissue management for nearly 60 years. However, it was not until the late 1960s that the principles of electrosurgery were understood and improved equipment became available. Part 1 of the two-part series covered the theory behind using this technique. Part 2 will now discusses the clinical applications.

Dental Restoration, Permanent↗
PubMed1992

Do children with developmental delays use more frequent and diverse language in verbal routines?

The current study is the first to test the hypotheses that children with developmental delays use more frequent language and more diverse vocabulary in routines than in nonroutines. The 19 child participants were in Brown's (1973) first stage of language learning. Using a novel method of measuring routines, 18 of the parents identified at least one routine in a videotaped play session with their children. Results support both hypotheses and provide descriptive information about the content of the routines displayed by the parents and children in the free-play context. The importance of replicating the findings in the context of an experimental design before concluding that "routineness" caused the children to talk more often and with more diverse vocabulary was emphasized.

Child↗