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Biomedical subjects

H Brady

Publications and source records attributed to H Brady.

13 recordsLinked to original sources
PubMed2003

Effects of SP500263, a novel selective estrogen receptor modulator, on bone, uterus, and serum cholesterol in the ovariectomized rat.

We describe here the activity of a novel selective estrogen receptor modulator, SP500263. When given to adult ovariectomized (OVX) rats for 28 days at doses of 0.3, 1, or 3 mg/kg/day, we found that SP500263 partially protected against OVX-induced loss of bone mineral content in the distal ends of femurs and in the whole bone. SP500263 also antagonized the OVX-induced increase in body weight. However, unlike 17beta-estradiol, SP500263 at efficacious doses did not prevent the OVX-induced loss in uterine wet weight. A small but significant effect on uterine wet weight was noted with raloxifene dosed at 1 mg/kg. As expected, SP500263 but not raloxifene acted as an estrogen antagonist on the uterus in adult rats when administered for 7 days at 30 mg/kg/day. Finally, SP500263 had no statistically significant effects on total serum cholesterol and serum triglycerides in OVX rats treated for 28 days. Raloxifene had no significant effects on body weight, bone mineral content, and serum cholesterol or triglycerides in the OVX-rat model. In summary, SP500263 is a new orally active SERM that acts in rats as an estrogen agonist on bone without causing uterine stimulatory effects.

Administration, Oral↗
PubMed2001

Plasma P-selectin is elevated in the first trimester in women who subsequently develop pre-eclampsia.

OBJECTIVE: To report plasma concentrations of the adhesion cell molecule P-selectin during pregnancy to determine the effect of subsequent development of hypertension and pre-eclampsia. DESIGN: A longitudinal study. METHODS: A longitudinal study involving 70 women followed up from early pregnancy; 20 who subsequently developed pre-eclampsia were compared with 24 who developed gestational hypertension and 26 normotensive women with normal obstetric outcome. The determination of citrate plasma soluble P-selectin levels throughout pregnancy was performed using a commercial quantitative sandwich immunoassay kit. The temporal course of plasma P-selectin in the three groups of subjects was analysed. RESULTS: There was no significant difference in mean plasma P-selectin concentration between normotensive and gestational hypertensive subjects at any stage of pregnancy. Using a cutoff level of 60 ng/mL, P-selectin concentration at 10-14 weeks had a negative predictive value for pre-eclampsia of almost 99%. Mean plasma P-selectin concentrations were significantly elevated by 10-14 weeks in women who later developed pre-eclampsia (P < 0.001). CONCLUSIONS: Our data support an inflammatory model for pre-eclampsia whereby endothelial cell activation may be secondary to a primary inflammatory response. Plasma P-selectin has significant potential as a first trimester clinical marker of pre-eclampsia.

Adult↗
PubMed2001

Aggressive multiple myeloma presenting as mesenteric panniculitis.

Mesenteric panniculitis is a rare disease of the bowel mesentery, characterized by tumor-like infiltration by chronic inflammatory cells, fat necrosis, and fibrosis. Reported cases cited clinical presentation ranging from abdominal pain to fever of unknown origin, the majority of which were idiopathic and associated with a benign prognosis. We report the case of a 43-yr-old male who presented with malaise, weight loss, microcytic anemia, and a high erythrocyte sedimentation rate. Radiographic and histological investigations revealed typical features of mesenteric panniculitis. Initial treatment with high-dose oral prednisolone led to rapid and complete resolution of symptomatology, radiographic, and laboratory anomalies. Within 6 months, the patient presented again with anemia, renal failure, and hypercalcemia. A diagnosis of IgA kappa chain myeloma was made. Despite chemotherapy and restoration of normocalcemia, he died from refractory pulmonary edema. This is the first report of a hematological malignancy initially presenting with features of mesenteric panniculitis culminating in an aggressive course and a fatal outcome.

Adult↗
PubMed2000

Glutathione depletion-induced neutrophil apoptosis is caspase 3 dependent.

Resolving inflammation is a vital step in preventing the persistence of inflammatory disorders. Neutrophils play a major role in tissue damage associated with an inflammatory response. Their death by apoptosis is central to the final resolution of this response. Thiol depletion with diethylmaleate (DEM) or diamide represent important triggers for neutrophil apoptosis. The mechanism by which this process occurs remains unknown. The apoptotic cascade is associated with a number of cellular changes, including caspase activation and mitochondrial permeability. The aims of this study were to determine the role of mitochondrial permeability and the caspase cascade in thiol depletion-induced neutrophil apoptosis. Total cellular glutathione was reduced by DEM and diamide. This reduction was associated with neutrophil apoptosis and an increase in caspase 3 activity. The effects of DEM were blocked by the caspase 3 inhibitor, Z-DEVD-FMK. Mitochondrial permeability that occurred was also increased during this induction of apoptosis. Bongkrekic acid, a mitochondrial membrane stabilizer, inhibited DEM-induced apoptosis. The inhibitors' effects of LPS or GM-CSF on spontaneous neutrophil apoptosis was reversed by DEM, which was mediated by an increase in caspase 3 activity and independent of mitochondrial disruption. Caspase activation is an important step in glutathione depletion-induced apoptosis in resting and inflammatory neutrophils. Regulation of caspase activity may represent a possible target to trigger apoptosis and resolve inflammatory disorders.

Apoptosis↗
PubMed1996

Cloning and characterization of MEK6, a novel member of the mitogen-activated protein kinase kinase cascade.

Mitogen-activated protein kinases are members of a conserved cascade of kinases involved in many signal transduction pathways. They stimulate phosphorylation of transcription factors in response to extracellular signals such as growth factors, cytokines, ultraviolet light, and stress-inducing agents. A novel mitogen-activated protein kinase kinase, MEK6, was cloned and characterized. The complete MEK6 cDNA was isolated by polymerase chain reaction. It encodes a 334-amino acid protein with 82% identity to MKK3. MEK6 is highly expressed in skeletal muscle like many other members of this family, but in contrast to MKK3 its expression in leukocytes is very low. MEK6 is a member of the p38 kinase cascade and efficiently phosphorylates p38 but not c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) family members in direct kinase assays. Coupled kinase assays demonstrated that MEK6 induces phosphorylation of ATF2 by p38 but does not phosphorylate ATF2 directly. MEK6 is strongly activated by UV, anisomycin, and osmotic shock but not by phorbol esters, nerve growth factor, and epidermal growth factor. This separates MEK6 from the ERK subgroup of protein kinases. MEK6 is only a poor substrate for MEKK, a mitogen-activated protein kinase kinase kinase that efficiently phosphorylates the related family member JNKK.

Amino Acid Sequence↗
PubMed1993

GHF-1-promoter-targeted immortalization of a somatotropic progenitor cell results in dwarfism in transgenic mice.

During pituitary development, the homeo domain protein GHF-1 is required for generation of somatotropes and lactotropes and for growth hormone (GH) and prolactin (PRL) gene expression. GHF-1 mRNA is detectable several days before the emergence of GH- or PRL-expressing cells, suggesting the existence of a somatotropic progenitor cell in which GHF-1 transcription is first activated. We have immortalized this cell type by using the GHF-1 regulatory region to target SV40 T-antigen (Tag) tumorigenesis in transgenic mice. The GHF-Tag transgene caused developmental entrapment of somatotropic progenitor cells that express GHF-1 but not GH or PRL, resulting in dwarfism. Immortalized cell lines derived from a transgenic pituitary tumor maintain the characteristics of the somato/lactotropic progenitor in that they express GHF-1 mRNA and protein yet fail to activate GH or PRL transcription. Using these cells, we identified an enhancer that activates GHF-1 transcription at this early stage of development yet is inactive in cells representing later developmental stages of the somatotropic lineage or in other cell types. These experiments not only demonstrate the potential for immortalization of developmental progenitor cells using the regulatory regions from cell type-specific transcription factor genes but illustrate the power of such model systems in the study of developmental control.

Animals↗
PubMed1991

The pituitary-specific regulatory gene GHF1 contains a minimal cell type-specific promoter centered around its TATA box.

GHF-1 is a pituitary-specific transcription factor responsible for activation of the growth hormone (GH) gene. The GHF1 gene is expressed exclusively in cells of the somatotrophic lineage, and its transcription is extinguished in somatic cell hybrids. The minimal sequences required for differential transcription of GHF1 in GH-expressing and -nonexpressing cell lines and somatic cell hybrids were localized to a 15-bp region surrounding and including its TATA box. This 15-bp fragment acts as a cell type-specific promoter element and is recognized by a transcription factor present in GH-expressing cell lines. Hence, in addition to enhancers and upstream promoter elements, the TATA element (TATA box plus surrounding sequences) can be, in certain cases, an important determinant of cell-type-specific transcription.

Animals↗
PubMed1990

Regulation of the pituitary-specific homeobox gene GHF1 by cell-autonomous and environmental cues.

Homeodomain proteins function in determination of mating type in yeast, segmentation in fruit flies and cell-type specific gene expression in mammals. In Drosophila, expression of homeobox genes is controlled by cell-autonomous interactions between regulatory proteins and environmental clues. Similar controls may operate during mammalian limb development and frog embryogenesis. But, the exact way in which expression of homeodomain proteins is regulated in these systems is not clear and requires biochemical analysis of homeobox gene transcription. We now describe such an analysis of the GHF1 gene, which encodes a mammalian homeodomain protein specifying expression of the growth hormone (GH) gene in anterior pituitary somatotrophs. GHF1 is transcribed in a highly restricted manner and the presence of GHF1 protein is correlated both temporally and spatially with activation of the GH gene during pituitary development. Analysis of the GHF1 promoter indicates that transcription is also controlled by cell-autonomous interactions involving positive autoregulation by GHF1, and environmental cues that modulate the intracellular level of cyclic AMP and thereby the activity of cAMP response element binding protein (CREB), a ubiquitous transactivator that binds to the GHF1 promoter.

Animals↗