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Biomedical subjects

S Fox

Publications and source records attributed to S Fox.

At least 19 recordsLinked to original sources
PubMed1999

Early effects of hormone replacement therapy on bone.

Estrogen replacement is currently the preferred therapy for postmenopausal osteoporosis, although its mechanism of action remains poorly understood. Its primary action on bone is generally considered to be antiresorptive, but there is evidence in animals to suggest a stimulatory effect on bone formation. We have now attempted to detect a similar effect in humans by administering hormone replacement therapy (estradiol valerate 2 mg/day and dydrogesterone 5 mg/day given in a continuous, combined manner) to ten postmenopausal women. We carried out histomorphometric analyses of transiliac bone biopsies after quadruple tetracycline labeling, which was commenced before and continued during the first 4 weeks of hormone replacement therapy. Biochemical markers of bone turnover suggested that bone resorption decreased, but no significant effects on histomorphometric parameters of bone formation were detected. We conclude that hormone replacement therapy at the dose given does not stimulate bone formation in the iliac crest as assessed by histomorphometry.

Absorptiometry, Photon↗
PubMed1999

Investigation of under-ascertainment in epidemiological studies based in general practice.

BACKGROUND: One of the aims of the Study of Infectious Intestinal Disease (IID) in England is to estimate the incidence of IID presenting to general practice. This sub-study aims to estimate and correct the degree of under-ascertainment in the national study. METHODS: Cases of presumed IID which presented to general practice in the national study had been ascertained by their GP. In 26 general practices, cases with computerized diagnoses suggestive of IID were identified retrospectively. Cases which fulfilled the case definition of IID and should have been ascertained to the coordinating centre but were not, represented the under-ascertainment. Logistic regression modelling was used to identify independent factors which influenced under-ascertainment. RESULTS: The records of 2021 patients were examined, 1514 were eligible and should have been ascertained but only 974 (64%) were. There was variation in ascertainment between the practices (30% to 93%). Patient-related factors independently associated with ascertainment were: i) vomiting only as opposed to diarrhoea with and without vomiting (OR 0.37) and ii) consultation in the surgery as opposed to at home (OR 2.18). Practice-related factors independently associated with ascertainment were: i) participation in the enumeration study component (OR 1.78), ii) a larger number of partners (OR 0.3 for 7-8 partners); iii) rural location (OR 2.27) and iv) previous research experience (OR 1.92). Predicted ascertainment percentages were calculated according to practice characteristics. CONCLUSION: Under-ascertainment of IID was substantial (36%) and non-random and had to be corrected. Practice characteristics influencing variation in ascertainment were identified and a multivariate model developed to identify adjustment factors which could be applied to individual practices. Researchers need to be aware of factors which influence ascertainment in acute epidemiological studies based in general practice.

Adolescent↗
PubMed1998

A physical map of 30,000 human genes.

A map of 30,181 human gene-based markers was assembled and integrated with the current genetic map by radiation hybrid mapping. The new gene map contains nearly twice as many genes as the previous release, includes most genes that encode proteins of known function, and is twofold to threefold more accurate than the previous version. A redesigned, more informative and functional World Wide Web site (www.ncbi.nlm.nih.gov/genemap) provides the mapping information and associated data and annotations. This resource constitutes an important infrastructure and tool for the study of complex genetic traits, the positional cloning of disease genes, the cross-referencing of mammalian genomes, and validated human transcribed sequences for large-scale studies of gene expression.

Animals↗
PubMed1998

TRANCE is necessary and sufficient for osteoblast-mediated activation of bone resorption in osteoclasts.

TRANCE (tumor necrosis factor-related activation-induced cytokine) is a recently described member of the tumor necrosis factor superfamily that stimulates dendritic cell survival and has also been found to induce osteoclastic differentiation from hemopoietic precursors. However, its effects on mature osteoclasts have not been defined. It has long been recognized that stimulation of osteoclasts by agents such as parathyroid hormone (PTH) occurs through a hormonal interaction with osteoblastic cells, which are thereby induced to activate osteoclasts. To determine whether TRANCE accounts for this activity, we tested its effects on mature osteoclasts. TRANCE rapidly induced a dramatic change in osteoclast motility and spreading and inhibited apoptosis. In populations of osteoclasts that were unresponsive to PTH, TRANCE caused activation of bone resorption equivalent to that induced by PTH in the presence of osteoblastic cells. Moreover, osteoblast-mediated stimulation of bone resorption was abrogated by soluble TRANCE receptor and by the soluble decoy receptor osteoprotegerin (OPG), and stimulation of isolated osteoclasts by TRANCE was neutralized by OPG. Thus, TRANCE expression by osteoblasts appears to be both necessary and sufficient for hormone-mediated activation of mature osteoclasts, and TRANCE-R is likely to be a receptor for signal transduction for activation of the osteoclast and its survival.

Animals↗
PubMed1998

A phase II trial of paclitaxel in refractory germ cell tumors.

BACKGROUND: A significant percentage of patients with refractory germ cell tumors will not respond to standard salvage regimens. Thus there is a need for new active agents. Paclitaxel has demonstrated activity against a variety of solid tumors in both laboratory and clinical studies. METHODS: Eighteen patients with refractory germ cell tumors who failed initial cisplatin-based chemotherapy and a maximum of 2 salvage regimens were enrolled into a Phase II trial of paclitaxel at a dose of 170 mg/m2 by intravenous infusion over 24 hours every 21 days without growth factor support. The median age of the patients was 32.5 years (range, 18-49 years). The testis was the primary site of tumor for 13 patients (72%) and the tumor was extragonadal in 5 patients (28%). Six patients (33%) were late recurrences. Twelve patients (67%) had > or = 2 metastatic sites. The median number of previous chemotherapy cycles was six (range, four to nine). Three patients (17%) previously had undergone autologous bone marrow transplantation. RESULTS: Two patients (11%) responded to paclitaxel. Major toxicities were Grade 3-4 neutropenia (55% of patients) and Grade 3-4 neurotoxicity (2 patients). Neutropenic fever occurred in 3 patients (17%). CONCLUSIONS: Paclitaxel demonstrated minimal activity in heavily pretreated patients with multiple, poor risk clinical features. These results in part may be due to the unfavorable characteristics of the patients in the current study, specifically the high percentage of patients with late recurrences and extragonadal primary tumors, both of which are known to respond poorly to salvage therapy. Other trials with different patient populations and doses of paclitaxel reported response rates ranging from 13.3%-26%. The role of paclitaxel in the treatment of patients with refractory germ cell tumors remains to be defined in future studies.

Adolescent↗
PubMed1998

Paclitaxel plus gallium nitrate and filgrastim in patients with refractory malignancies: a phase I trial.

To determine the maximally tolerated dose of paclitaxel with and without filgrastim (G-CSF) when administered as a 24-hour intravenous infusion after a 120-hour infusion of gallium nitrate at a fixed dose of 300 mg/m2/24 hours, 40 patients were entered onto a trial lasting from September 1994 to September 1996. Eligibility included a diagnosis of an advanced malignancy not amenable to curative therapy and up to one previous chemotherapy regimen for metastatic disease. Gallium was administered at a fixed dose of 300 mg/m2/day as a continuous intravenous infusion for 120 hours. Paclitaxel starting at 90 mg/m2 was given concurrently with the last 24 hours of the gallium as a 24-hour intravenous infusion. Cycles were repeated every 21 days. Once the maximum tolerated dose (MTD) of paclitaxel was reached, G-CSF (5 microg/kg/day days 7-16) was added and paclitaxel dose escalation continued. The MTD for paclitaxel without G-CSF was 110 mg/m2 and 225 mg/m2 with G-CSF, with neutropenia being the dose-limiting toxicity. A partial response was noted in a patient who had thymoma and a complete response was achieved in a patient who had colon cancer. The recommended phase II dosage is gallium nitrate at 300 mg/m2/day over 120 hours, with paclitaxel at 110 mg/m2 over 24 hours without G-CSF or 225 mg/m2 over 24 hours with G-CSF and 0.5 mg calcitriol on days 1 through 7. Further trials of this modified regimen for outpatient administration are in progress.

Adult↗
PubMed1998

Paclitaxel (Taxol) plus doxorubicin plus filgrastim in advanced sarcoma: a phase II study.

The authors evaluated the novel chemotherapeutic regimen of paclitaxel (Taxol, Bristol-Myers Squibb, Princeton, NJ, U.S.A.) plus doxorubicin plus filgrastim--a granulocyte colony-stimulating factor (G-CSF)--in advanced or metastatic sarcoma. Eligible patients must have had histologically confirmed advanced previously untreated soft-tissue sarcoma. All patients must have had bidimensionally measurable metastases. Treatment consisted of doxorubicin, 50 mg/m2 by intravenous push, followed 4 hours later by paclitaxel, 150 mg/m2 by continuous infusion over 24 hours every 3 weeks, plus G-CSF, 5 microg/kg, on days 3 through 12 of each cycle. Cycles were repeated every 21 days. A one-time dose escalation for doxorubicin only (60 mg/m2) was allowed in all patients who experienced no significant toxicity after their first cycle of paclitaxel plus doxorubicin. From November 1993 through May 1996, 29 patients were entered in this study. Grade 3 anemia occurred in three patients. Grade 3--4 neutropenia occurred in 20 patients. Seven patients experienced at least one episode of neutropenic fever, including one death. Grade 3 thrombocytopenia occurred in four patients. There were six partial responses in 27 eligible patients, for a response rate of 22.2% (95% confidence interval, 7%-38%). Median time to progression was 4.5 months, and median overall survival was 10.2 months. The regimen of paclitaxel plus doxorubicin plus filgrastim as used in this study appears to have no more activity than single-agent doxorubicin.

Adult↗
PubMed1998

The brain tumor experience and quality of life: a qualitative study.

Despite the attention given to quality of life (QOL) in persons with cancer, very little is currently know about QOL in persons with brain tumors. In the past twenty years, less than twenty articles reflect the actual measurement of QOL in adult brain tumor population. The shortage of QOL studies is disturbing considering the slow progress made in extending the life expectancy of many brain tumor patients and the toxicities of many existing treatment protocols. This qualitative study was undertaken to begin to fill the gaps in the existing literature and to more clearly define QOL in persons with brain tumors. The researchers used an exploratory, descriptive design involving semi-structured interviews of adults with brain tumors and their significant others. Twenty-three adults with brain tumors and 21 significant others were interviewed. Data analysis of interview transcripts focused on the identification of key variables contributing to the QOL of adults with brain tumors. Using constant comparative methods, it was found that data could be organized into five thematic categories: (1) The Stigma of a Mind-Body Illness, (2) An Invasive Disease of the Self, (3) My Family has a Brain Tumor, (4) Dealing with the Medical Diplomats, and (5) Quality of Life: No Substitute for Living. These emerging themes provide information which clinicians caring for brain tumor patients can use to provide care and anticipatory guidance. Unique areas for further research elicited in the study include exploration of the "loss of self" theme, how persons use their estimations of QOL in decision-making and examination of the balance between the need for survival and maintaining QOL.

Adaptation, Psychological↗
PubMed1998

Use of a quality of life instrument to improve assessment of brain tumor patients in an outpatient setting.

Persons with brain tumors experience their illness in a way that is much larger than the sum of their symptoms. Using a QOL tool to improve assessment can assist the patient, family and clinician in considering all aspects of the experience of having a brain tumor. The tool selected should be easy to use, brief and address the major dimensions of quality of life. The Quality of Life Index is one such tool. The Quality of Life Index assists the clinician in assessing five major categories of a person's illness experience. These include the impact of the brain tumor diagnosis on work-related activities, activities of daily living, general health, support systems and outlook or mood. By using a quality of life instrument such as the Quality of Life Index to improve assessment, clinicians will be able to provide brain tumor patients with focused care to improve their daily lives.

Ambulatory Care↗
PubMed1998

Role for parathyroid hormone in mechanical responsiveness of rat bone.

We investigated the relationship between parathyroid hormone (PTH) and mechanical stimulation in mechanically induced osteogenesis. In normal rats, mechanical stimulation of the eight caudal vertebra induced an osteogenic response. This was augmented by a single injection of human PTH-(1-34) 30-45 min before loading. No osteogenic response was seen in thyroparathyroidectomized (TPTX) rats; the osteogenic response was restored by a single injection of PTH before stimulation, suggesting that physiological levels of PTH are necessary for the mechanical responsiveness of bone. c-fos expression was detected only in the osteocytes of those rats that were both mechanically stimulated and given PTH. This suggests that PTH supports mechanically induced osteogenesis by sensitizing either the strain-sensing mechanism itself or early responses of bone to strain-generated signals. The osteogenic response was not augmented by two further daily injections of PTH and was not seen in TPTX rats in which PTH administration was started 3 days after loading. These results reveal a major role for PTH in the mechanical responsiveness of rat bone.

Animals↗
PubMed1997

Expression of the angiogenic factors vascular endothelial cell growth factor, acidic and basic fibroblast growth factor, tumor growth factor beta-1, platelet-derived endothelial cell growth factor, placenta growth factor, and pleiotrophin in human primary breast cancer and its relation to angiogenesis.

Angiogenesis is a significant prognostic factor in breast cancer, but the factors that control angiogenesis in vivo are not well defined. Multiple angiogenic polypeptides are known, and we have determined the expression of seven of these in primary human breast cancers; the relationship of expression to estrogen receptor and vascular density was also examined. Vascular endothelial growth factor (VEGF) and its four isoforms (121, 165, 189, and 206 amino acids), transforming growth factor (TGF)-beta1, pleiotrophin, acidic and basic fibroblast growth factor (FGF), placental growth factor, and thymidine phosphorylase (platelet-derived endothelial cell growth factor) were quantitated by RNase protection analysis. beta-FGF was also measured by ELISA. The estrogen receptor (ER), epidermal growth factor receptor, and vascular density were analyzed in 64 primary breast cancers. All tumors expressed at least six different vascular growth factors. VEGF was most abundant, and the transcript for the 121-amino acid form predominated. Other angiogenic factors expressed at high levels were thymidine phosphorylase and TGF-beta1. Expression of most of the angiogenic factors did not correlate with that of ER or vascular density. However, thymidine phosphorylase did, with a correlation coefficient of 0.3 (P = 0.03). There were significant associations of pleiotrophin with acidic FGF expression (P = 0.001) and TGF-beta with platelet-derived endothelial cell growth factor expression (P = 0.001). Thus, angiogenesis may involve a coordinate regulation of some vascular growth factors. High VEGF expression correlated with poor prognosis in univariate analysis (P = 0.03), as did ER and epidermal growth factor receptor expression. Basic FGF was also assessed by ELISA and was more highly expressed in tumors than normal breast tissues (median, 346 microg/ml cytosol; range, 54-1323 versus median, 149; range, 32-509; P = 0.01). Implications for therapy are that broad spectrum agents that block features common to these factors may be useful (e.g., antagonism of heparin-binding activity agents), because so many angiogenic factors are expressed. Inhibiting endothelial migration or agents directly toxic to endothelium would be of value in a combined approach to therapy.

Breast Neoplasms↗
PubMed1997

Catecholamine modulation of lymphocyte homing to lymphoid tissues.

Lymphocyte migration is an essential process for immune surveillance and for promoting cell-cell interactions necessary to generate an immune response. This report examined whether catecholamine prestimulation would alter the pattern of lymphocyte homing to spleen and lymph nodes in mice as determined by tracking fluorescently labeled cells. The results of cell sorter analysis showed that catecholamine-pretreated cells had increased accumulation in spleen and lymph nodes 1 and 2 h after i.v. injection. In addition, microscopic analysis showed that labeled cells migrated from the splenic red pulp to T-cell regions of the white pulp over a 2-h time course. Within the lymph nodes, labeled cells localized predominantly to the pericortex. Additional studies examined the migration of lymphocytes to lymphoid tissues of NGF-transgenic mice that have sympathetic hyperinnervation of spleen and peripheral lymph nodes. In contrast to the studies above, migration of T-cells from control mice to lymphoid tissues of the hyperinnervated mice was not different than that in control mice in most tissues. The accumulation of lymphocytes in lymphoid tissues is a balance between the influx of newly migrated cells and efflux back into the circulation. The studies in this report lend support to other studies showing catecholamine modulation of lymphocyte migration and homing, but it is a complex process about which much has yet to be understood.

Adrenergic beta-Agonists↗
PubMed1997

HSF1 granules: a novel stress-induced nuclear compartment of human cells.

Heat shock factor 1 (HSF1) is the ubiquitous stress-responsive transcriptional activator which is essential for the inducible transcription of genes encoding heat shock proteins and molecular chaperones. HSF1 localizes within the nucleus of cells exposed to heat shock, heavy metals, and amino acid analogues, to form large, irregularly shaped, brightly staining granules which are not detected during attenuation of the heat shock response or when cells are returned to their normal growth conditions. The kinetics of detection of HSF1 granules parallels the transient induction of heat shock gene transcription. HSF1 granules are also detected using an HSF1-Flag epitope tagged protein or a chimeric HSF1-green fluorescent protein which reveals that these nuclear structures are stress-induced and can be detected in living cells. The spatial organization of HSF1 granules in nuclei of stressed cells reveals that they are novel nuclear structures which are stress-dependent and provides evidence that the nucleus undergoes dynamic reorganization in response to stress.

Amino Acids↗
PubMed1997

The role of the nurse with families of patients in ICU: the nurses' perspective.

Although nurses are often charged with the responsibility of helping families cope with the stress that results when a loved one is hospitalized in a critical care unit, there is little research investigating how critical care nurses perceive their role with families. The objectives of this study were to (a) describe critical care nurses' role expectations and perceived role performance with respect to patients' families, and (b) describe the relationship between nurses' role expectations and their perceived role performance. Forty-seven nurses were surveyed in this descriptive, correlational study. There was a moderately strong correlation (r = .60, p < .0001) between role expectations and role performance. However, family-focused interventions requiring less time and less intense communication skills were performed more often than those requiring more time and greater skill in communication. Thus, certain family needs may be met inconsistently due to varied perceptions among nurses regarding their responsibility to families. The findings are discussed in relation to concepts from role theory.

Adult↗
PubMed1997

Non-small-cell lung carcinoma tumor growth without morphological evidence of neo-angiogenesis.

Neoplastic growth is usually dependent on blood supply, and it is commonly accepted that this is provided by the formation of new vessels. However, tumors may be able to grow without neovascularization if they find a suitable vascular bed available. We have investigated the pattern of vascularization in a series of 500 primary stage I non-small-cell lung carcinomas. Immunostaining of endothelial cells has highlighted four distinct patterns of vascularization. Three patterns (which we called basal, papillary, and diffuse) have in common the destruction of normal lung and the production of newly formed vessels and stroma. The fourth pattern, which we called alveolar or putative nonangiogenic, was observed in 16% (80/500) of the cases and is characterized by lack of parenchymal destruction and absence of both tumor associated stroma and new vessels. The only vessels present were the ones in the alveolar septa, and their presence highlighted, through the whole tumor, the lung alveoli filled up by the neoplastic cells. This observation suggests that, if an appropriate vascular bed is available, a tumor can exploit it and grows without inducing neo-angiogenesis. This could have implications for strategies aimed at inhibiting tumor growth by vascular targeting or inhibition of angiogenesis.

Biomarkers, Tumor↗
PubMed1996

A mixed-metal pentanuclear complex containing linked NiIIN2S2 and CuII units.

Bis[(1S,2S)-trans-3,3'-(1,2-cyclohexanediyldinitrilo)bis- (2-methylpropane-2-thiolato)]-1 kappa 4N1,N1',S1,S1';2 kappa 4N2,- N2',S2,S2';3 kappa 2S1,S2';4 kappa 2S1',S2;5 kappa 2S1',S2'-triiodo-3 kappa I, 4 kappa I,- 5 kappa I-tricopper(I)dinicke1(II) bis(acetonitrile) solvate, [[Ni(C14H28N2S2)]2(CuI)3]. 2CH3CN, is one of a number of possible novel pentanuclear complexes formed from MIIN2S2 units with available donating thiolate ligands. In the title compound, three CuII groups bridge thiolate ligands from two approximately square-planar [NiIIN(amine)2S(thiolate)2] units to form the pentanuclear complex. The coordination geometry of each Cu atom is approximately trigonal planar.

Crystallography, X-Ray↗
PubMed1996

Normethylclozapine potentiates the action of quinpirole in the 6-hydroxydopamine lesioned rat.

Systemic administration of the 5-HT2c receptor antagonist, normethylclozapine, to previously untreated unilaterally 6-hydroxydopamine-lesioned rats elicits rotations contraversive to the lesion when given with a subthreshold dose of the dopamine D2 receptor agonist, quinpirole. Normethylclozapine alone does not possess any anti-parkinsonian action. In animals which have previously received dopamine replacement therapy, i.e. primed, normethylclozapine potentiates the contraversive rotations induced by quinpirole. We speculate that these actions may result from reduced excitation of the output regions of the basal ganglia. 5-HT2c receptor antagonists may have potential as treatment for Parkinson's disease in combination with dopamine receptor agonists.

Animals↗