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C Fletcher

Publications and source records attributed to C Fletcher.

At least 37 records · Page 2Linked to original sources
PubMed1997

Long-term monitoring of circadian rhythms in c-fos gene expression from suprachiasmatic nucleus cultures.

BACKGROUND: The AP-1 family of transcription factors has been implicated in the control of the expression of many genes in response to environmental signals. Previous studies have provided temporal profiles for c-fos expression by taking measurements from many animals at several points in time, but these studies provide limited information about dynamic changes in expression. Here, we have devised a method of continuously measuring c-fos expression. RESULTS: A transgenic mouse line expressing the human c-fos promoter linked to the firefly luciferase reporter gene (fos/luc) was generated to continuously monitor c-fos gene expression. A second transgenic mouse line expressing luciferase under the control of the cytomegalovirus promoter (CMV/luc) served as a control. Luminescence originating from identifiable brain regions was imaged from fos/luc brain slice cultures. Expression of the fos/luc transgene accurately reflected transcriptional responses of the endogenous c-fos gene. Dynamic changes in fos/luc expression in suprachiasmatic nuclei (SCN) explant cultures were monitored continuously, and luminescence showed almost 24 hour rhythms lasting up to five circadian cycles. In contrast, bioluminescence monitored from CMV/luc SCN explant cultures was not rhythmic. CONCLUSION: The fos/luc transgenic mouse will be useful for long-term, non-invasive monitoring of c-fos transcriptional responses to the changing cellular environment. Circadian rhythms in c-fos expression can be monitored non-invasively in real time from the SCN, clearly demonstrating that c-fos transcription is regulated by the circadian clock.

Animals↗
PubMed1996

Trisomies 8 and 20 in desmoid tumors.

A nonrandom occurrence of trisomy 8 and of trisomy 20 in desmoid tumors has been recently reported. The finding of trisomy 8 in nondividing desmoid tumor cells by in situ hybridization prompted us to evaluate, in a similar way, the occurrence of trisomy 20 and the possible occurrence of both trisomies together because their co-existence was cytogenetically observed in a few cases. Double fluorescence in situ hybridization (FISH) with centromeric probes for chromosomes 8 and 20 was performed on 16 single cell suspensions of desmoid tumors. FISH confirmed the occurrence of trisomy 8 or 20 in a single cell suspension of desmoid tumors. Both individual trisomies, and even more their association in the same cells, are rare to extremely rare in solid tumors in general and in mesenchymal tumors in particular, and are only known to occur in infantile fibrosarcoma.

Adolescent↗
PubMed1995

Murine chromosomal location of eight members of the hepatocyte nuclear factor 3/fork head winged helix family of transcription factors.

A 100-amino-acid DNA-binding motif, known as the winged helix, was first identified in the mammalian hepatocyte nuclear factor-3 (HNF-3) and Drosophila fork head family of transcription factors. Subsequently, more than 40 different genes that contain the winged helix motif have been identified. In the studies described here, we have determined the murine chromosomal location of eight members of this gene family, HFH-1, HFH-3, HFH-4, HFH-5, HFH-6, HFH-8, BF-1, and BF-2, by interspecific backcross analysis. These genes, designated HNF-3 fork head homolog 1 (Hfh1), Hfh3, Hfh4, Hfh5, Hfh6, Hfh8, Hfh9, and Hfh10, respectively, mapped to 6 different mouse autosomes and are thus well dispersed throughout the mouse genome. Based on this mapping information, we predict the chromosomal location of these genes in humans and discuss the potential of these genes as candidates for uncloned mouse mutations.

Amino Acid Sequence↗
PubMed1995

Surveillance of adverse reactions in patients self-infusing intravenous immunoglobulin at home.

This is the first prospective study of adverse reactions occurring in primary-antibody-deficient patients self-infusing intravenous immunoglobulin at home. One hundred nineteen patients, already self-infusing at home, were entered into the study. They had been fully instructed about all aspects of adverse reactions, including their prevention and treatment. In the event of any adverse reaction, a form was completed detailing the product, the dose, the symptoms that occurred and the time they lasted, the rate of infusion, and other relative information such as predisposing factors and any medication taken. The severity of reactions were classified as mild, moderate, or severe. The total number of reactions documented was 19 in 2031 infusions, and all resolved without medical aid. No serious reactions occurred. Excluding those reactions in which predisposing factors were identified, the overall reaction rate was 0.7%. In conclusion the study showed the reaction rate in patients self-infusing intravenous immunoglobulin at home was low following formal training of selected patients at recognized training centers.

Adolescent↗
PubMed1995

Population differences in ganciclovir clearance as determined by nonlinear mixed-effects modelling.

We examined the pharmacokinetics of ganciclovir in different populations of cytomegalovirus (CMV)-infected patients through the use of nonlinear mixed-effects modelling. As expected, patient weight and estimated creatinine clearance were shown to be important covariates in the serum ganciclovir clearance. Unexpectedly, major differences in ganciclovir clearance between different populations of patients were found. Human immunodeficiency virus (HIV)-infected patients with CMV retinitis cleared ganciclovir 41% faster than HIV-infected patients only shedding CMV into the urine. Solid-organ transplant patients had a serum clearance one-fourth that of HIV-infected patients, even with correction for creatinine clearance. These findings require prospective validation and may have important implications for ganciclovir dosing in different populations of CMV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1995

Management and prevention of osteoporosis.

1. Osteoporosis is an increasing healthcare problems in terms of pain, morbidity and mortality. 2. A decrease in bone density can lead to fractures of the spine, hip and wrists (sites particularly high in trabecular bone). 3. Certain risk factors can predispose to osteoporosis.

Aged↗
PubMed1995

Amyloid tumour of the rectum.

Systemic amyloidosis results in diffuse deposition of amyloid proteins in various organs. Localized deposits in the form of nodules also occur but are rare in the gastrointestinal tract. A localized amyloid deposit in the rectum that was clinically indistinguishable from carcinoma of the rectum or prostate is described.

Aged↗
PubMed1995

t(9;22)(q22-31;q11-12) is a consistent marker of extraskeletal myxoid chondrosarcoma: evaluation of three cases.

Three cases of extraskeletal myxoid chondrosarcoma with typical histologic and ultrastructural features were investigated cytogenetically. All three cases showed a reciprocal chromosome translocation characterized as t(9;22)(q22-31)(q11-12), thus confirming the findings in three previously karyotyped cases of extraskeletal myxoid chondrosarcoma in the literature. These data add significantly to the evidence of t(9;22) being diagnostic for extraskeletal myxoid chondrosarcoma. Other previously published cases with a range of complex karyotypes were less well defined morphologically. In cases with limited diagnostic material this karyotype might facilitate distinction from myxoid liposarcoma, which consistently shows t(12;16). Clear cell sarcoma, Ewing's sarcoma/primitive neuroectodermal tumor, and desmoplastic round cell tumor also show involvement of chromosome 22 with formation of a hybrid gene between the Ewing's sarcoma gene on band q12 and a transcription factor gene. Whether rearrangement of the Ewing's sarcoma gene is also present in extraskeletal myxoid chondrosarcoma is not clear at present. Cloning of the (9;22) translocation might provide important clues to the pathogenesis of this type of chondrosarcoma.

Adult↗
PubMed1994

Maintenance of Wnt-3 expression in Purkinje cells of the mouse cerebellum depends on interactions with granule cells.

Wnt genes encode secreted proteins implicated in cell fate changes during development. To define specific cell populations in which Wnt genes act, we have examined Wnt expression in the cerebellum. This part of the brain has a relatively simple structure and contains well-characterized cell populations. We found that Wnt-3 is expressed during development of the cerebellum and that expression is restricted to the Purkinje cell layer in the adult. Wnt-3 expression in Purkinje cells increases postnatally as granule cells start to make contacts with Purkinje cells. To investigate whether interactions with granule cells influence Wnt-3 expression in Purkinje cells, we examined gene expression in several mouse mutants, using the expression of En-2 to follow the fate of granule cells. In the weaver mutant, in which granule cells fail to migrate and subsequently die in the external granular layer, Wnt-3 expression was normal at postnatal day 15 (P15). At that time, some granule cells are still present in the external granular layer. At P28, however, when granule cells could no longer be detected, Wnt-3 expression was almost absent. In the meander tail mutant, in which the anterior cerebellar lobes lack granule cells, Wnt-3 expression was only detected in the normal posterior lobes. Since En genes are implicated in cell-cell interactions mediated by Wnt genes, we examined En-2/En-2 mutant mice, finding normal Wnt-3 expression, indicating that the effect of granule cells on the maintenance of Wnt-3 is not mediated by En-2. Our results show that Wnt-3 expression in Purkinje cells is modulated by their presynaptic granule cells at the time of neuronal maturation.

Animals↗
PubMed1994

Effect of aqueous neem (Azadirachta indica) extract on testosterone and other blood constituents in male rats. A pilot study.

Effect of oral administration of crude aqueous neem extract on serum testosterone and other blood constituents was studied in the male Wistar rats for 10 weeks. The neem treatment resulted in significant decreases (p < 0.01) in total testosterone, total bilirubin and K+ in serum. There were also increases (p < 0.05) in packed cell volume, mean corpuscular haemoglobin concentration, red blood cell, white blood cell and lymphocyte counts without showing any cytotoxic effects in the body.

Administration, Oral↗
PubMed1993

Macrophage-tumor cell associations: a factor in metastasis of breast cancer?

In human breast carcinomas tumor cells and macrophages are often proximal. We previously reported on the relationship between tumor cell growth and macrophage concentration and report here on the possible involvement of macrophages in the metastatic process. We hypothesize that during the initial stages of metastasis, tumor cells are likely to encounter macrophages and form aggregates. Using a cell culture method that encourages cellular interactions, we found aggregates involving macrophages. Macrophages partly or completely surround other cell types without any apparent ill effect. Units involving macrophages and tumor cells would possess many properties necessary for invasion, which is a normal process for macrophages. Properties such as motility and production of specific enzymes necessary to traverse the extracellular matrix, basement membrane, and endothelial cell barriers may provide an advantage for tumor cells. Physical support and protection from immune recognition during transport of the tumor cell through the vascular system may also be enhanced, and paracrine growth stimulation and angiogenic activity may be provided at the new metastatic site. Verification of these observations in vivo could lead to new directions for limiting breast cancer metastasis.

Breast Neoplasms↗
PubMed1993

Attitudes towards a blind counselor and perceived effectiveness.

Attitudes towards a blind counselor and perceived effectiveness were evaluated using a videotape of a simulated counseling session. One group were told the counselor was a blind doctoral student whereas control participants were informed that the counselor was a doctoral student. Participants were then administered the Disability Factor Scale/B and the Barrett-Lennard Relationship Inventory. Analysis showed no difference in groups' scores on the Disability Factor Scale/B. A significant difference was obtained on one of the four scales of the Barrett-Lennard Relationship Inventory, i.e., the blind counselor was perceived to show significantly more unconditional regard.

Adult↗
PubMed1993

[Culture and mental illness among the Inuit of Nunavik].

While the major psychiatric disorders described in current nosology can be found among the Inuit of Northern Québec (Nunavik), there are important cultural influences on the symptomatology, social response and course of these disorders. A literature review, consideration of experiences with psychiatric consultation among the Inuit and the preliminary results of ongoing ethnographic research underscore the importance of the study of Inuit ethnopsychology and current attitudes toward the mentally ill in developing culturally sensitive psychiatric care.

Adult↗