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At least 217 records · Page 12Linked to original sources
PubMed2002

Are the effects of tamoxifen on the serum lipid profile modified by apolipoprotein E phenotypes?

BACKGROUND: Tamoxifen has favorable effects on the serum lipid profile. It has been suggested that the apolipoprotein (Apo) E phenotype can influence serum lipid parameters; the ApoE allele 4 (ApoE4) is associated with higher total and low-density lipoprotein (LDL) cholesterol levels. The ApoE phenotype also affects lipid responses to diets or treatment with statins. However, the effect of tamoxifen on the lipid profile in different ApoE phenotypes is unknown. PATIENTS AND METHODS: In the present study, we evaluated the effects of tamoxifen on the serum lipid profile in 11 ApoE4-positive postmenopausal women with breast cancer (phenotypes 3/4 and 4/4) compared with 33 ApoE4-negative women (phenotypes 3/2 and 3/3). Serum lipid parameters [high-density (HDL), LDL and total cholesterol, triglycerides, ApoAI, ApoB and lipoprotein (a)] were measured after an overnight fast before treatment and after 3 and 12 months. ApoE isoforms were determined by isoelectric focusing of delipidated very-low-density lipoproteins (VLDL). RESULTS: During the follow-up period, serum levels of total and LDL cholesterol and ApoB decreased significantly in both groups, but no significant differences were found. Concentrations of serum HDL cholesterol were not significantly different between both groups. However, serum ApoAI levels increased significantly in ApoE4-negative subjects (p = 0.00005), but no significant changes in ApoE4-positive women were observed. Serum triglyceride levels increased by 23.2% (p < 0.05) in ApoE4-positive patients, but they did not change significantly in ApoE4-negative patients. The LDL/HDL cholesterol ratio decreased similarly in the two groups, but the ApoAI/ApoB ratio, which may be a better predictor of cardiovascular events, significantly changed in the ApoE4-negative subjects. Finally, the median level of Lp(a) decreased by 43.4% in the ApoE4-negative patients, whereas it did not change significantly in the ApoE4-positive group. CONCLUSION: In postmenopausal Greek women with breast cancer, the levels of Lp(a) and triglycerides and the ApoAI/ApoB ratio respond more favorably to tamoxifen treatment in ApoE4-negative than in ApoE4-positive patients.

Aged↗
PubMed2004

Apolipoprotein E phenotype affects the malondialdehyde-modified LDL concentration and forearm endothelial function in postmenopausal women.

OBJECTIVE: We investigated whether the apolipoprotein E (apo E) phenotype affects the serum concentration of malondialdehyde-modified low-density lipoprotein (MDA-LDL) or forearm endothelial function in postmenopausal women. PATIENTS AND MEASUREMENTS: Individuals were divided into three groups according to their apo E phenotype: E2 (E2/2 and E2/3, n = 12); E3 (E3/3, n = 71); and E4 (E3/4 and E4/4, n = 27). The serum concentrations of lipids and MDA-LDL were measured. Forearm blood flow during reactive hyperaemia and after sublingual nitroglycerin administration was measured by strain-gauge plethysmography. RESULTS: The serum concentrations of total and LDL cholesterol were significantly higher in the E4 group than in the E2 group (P < 0.05) or in the E3 group (P < 0.05). The serum apo B concentration was significantly higher in the E4 group than in the E2 group (P < 0.05). The serum concentrations of high density lipoprotein (HDL) cholesterol and nitrite/nitrate were significantly lower in the E4 group than in the E2 group (P < 0.05). Other lipid concentrations did not differ in the three groups. The serum MDA-LDL concentration was highest in the E4 group, and was lowest in the E2 group (E2: 91.1 +/- 6.9 IU/l, E3: 112.3 +/- 5.9 IU/l, E4: 128.8 +/- 9.9 IU/l; P < 0.05). The forearm blood flow response to reactive hyperaemia was lowest in the E4 group, and highest in the E2 group (E2: 52.2 +/- 5.8 ml/min per 100 ml tissue, E3: 40.7 +/- 1.7 ml/min per 100 ml tissue, E4: 33.4 +/- 2.4 ml/min per 100 ml tissue; P < 0.05). The forearm blood flow changes in response to nitroglycerine were similar between all three groups. CONCLUSIONS: The apo E phenotype affects the serum MDA-LDL concentration and forearm endothelial function in postmenopausal women.

Aged↗
PubMed1993

Transcellular biosynthesis of arachidonic acid metabolites: from in vitro investigations to in vivo reality.

The discovery that arachidonic acid metabolism in a multicellular environment could be different from that expected from the sum of individual cell types has led to the concept of transcellular metabolism. In this process, several cells can contribute to the formation of a novel compound with potent biological action. The study of this mode of synthesis is important in the context of the current appraisal of thrombotic diseases as part of an inflammatory reaction. In this context, blood cell-vessel wall interactions present a regulated expression of adhesive molecules on either type of cell. These complex processes are initiated by signalling molecules such as cytokines that can deeply modify the phenotype of endothelial cells, which may ultimately lead to a change in the vascular tone and to atherosclerotic complications. Such reaction processes are part of the autocrine-endocrine system whereby cells can control and modify their own phenotype through the action of a local network of mediators. In this context, arachidonic acid metabolites may be an important part of unifying signal molecules that participate in these changes. The significance of transcellular biosynthesis where combined cells acquire a different metabolic potential can be viewed as an additional modification of blood cell and vessel cell phenotype in thrombotic diseases.

Animals↗
PubMed2006

Refining the attention deficit hyperactivity disorder phenotype for molecular genetic studies.

It is well established that attention deficit hyperactivity disorder (ADHD) is a familial and highly heritable disorder. Consequently, much effort is being directed towards searching for specific susceptibility genes. There is a growing trend, across the field of complex disease genetics, towards undertaking secondary analyses based on refined phenotypic definitions and in testing whether specific susceptibility genes modify the phenotypic presentation of the disorder in question. It is crucial that good, empirically derived arguments are made before undertaking multiple analyses on different phenotype refinements. In this review article, we consider the evidence from genetic epidemiological studies as well as key clinical studies that provide guidance on examining the ADHD phenotype for the purpose of molecular genetic studies. Specifically, findings on categorical versus dimensional conceptualisations of ADHD, reporter effects, comorbidity, ADHD subtypes and persistence are reviewed. Current evidence suggests that for the purpose of identifying susceptibility genes for ADHD, parent and teachers should be used as informants and that focusing on the clinical diagnosis of ADHD is useful. There is also good empirical support in favour of examining antisocial behaviour in ADHD. Genetic studies of dimensional ADHD are useful for other complementary purposes.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

Prior appendectomy and the phenotype and course of Crohn's disease.

AIM: To determine whether prior appendectomy modifies the phenotype and severity of Crohn's disease. METHODS: Appendectomy status and smoking habits were specified by direct interview in 2838 patients consecutively seen between 1995 and 2004. Occurrence of complications and therapeutic needs were reviewed retrospectively. Additionally, annual disease activity was assessed prospectively between 1995 and 2004 in patients who had not had ileocecal resection and of a matched control group. RESULTS: Compared to 1770 non-appendectomized patients, appendectomized patients more than 5 years before Crohn's disease diagnosis (n=716) were more often females, smokers, with ileal disease. Cox regression showed that prior appendectomy was positively related to the risk of intestinal stricture (adjusted hazard ratio, 1.24; 95% confidence interval, 1.13 to 1.36; P=0.02) and inversely related to the risk of perianal fistulization (adjusted hazard ratio, 0.75; 95% confidence interval, 0.68 to 0.83; P=0.002). No difference was observed between the two groups regarding the therapeutic needs, except for an increased risk of surgery in appendectomized patients, attributable to the increased prevalence of ileal disease. Between 1995 and 2004, Crohn's disease was active during 50% of years in appendectomized patients (1318 out of 2637 patient-years) and 51% in non-appendectomized patients (1454 out of 2841 patient-years; NS). CONCLUSION: Prior appendectomy is associated with a more proximal disease and has an increased risk of stricture and a lesser risk of anal fistulization. However, the severity of the disease is unaffected.

Adolescent↗
PubMed2001

Variable phenotype of Alzheimer's disease with spastic paraparesis.

A variant form of Alzheimer's disease (AD), in which spastic paraparesis (SP) precedes dementia, is characterised by large, noncored, weakly neuritic Abeta-amyloid plaques resembling cotton wool balls and is caused by genomic deletion of presenilin 1 exon 9. A pedigree with a 5.9 kb exon 9 deletion shows a phenotypic spectrum including subjects with typical AD or with SP and numerous cotton wool plaques. In SP subjects, dementia onset is delayed and modified. This phenotypic variation suggests that modifying factors are associated with exon 9 deletions.

Adult↗
PubMed2006

Genetic and environmental modifiers of Alzheimer's disease phenotypes in the mouse.

As a group, strains of laboratory mice carrying Alzheimer's disease (AD)-related transgenes are currently the most widely studied animal models of AD. Many AD mouse models carrying the same or similar transgene constructs demonstrate strikingly different phenotypic responses to transgene expression, mimicking the apparent genetic complexity of AD pathogenesis seen in the human population. Genetic differences between the numerous mouse model strains used for AD research can significantly affect correct interpretation and cross-comparison of experimental findings, making genetic background an important consideration for all work in mouse models of AD. Furthermore, because of the potential for discovering novel genetic modifiers of AD pathogenesis, the effects of genetic background on AD phenotypes in the mouse can prove a worthwhile subject of study in their own right. This review discusses the implications of genetic modifiers for mouse and human AD research, and summarizes recent findings identifying significant roles for genetic background in modifying important phenotypes in AD mouse models, including premature death, amyloid deposition, tau hyperphosphorylation, and responsiveness to environmental or treatment interventions.

Alzheimer Disease↗
PubMed2000

Clinical variability among patients with incomplete X-linked congenital stationary night blindness and a founder mutation in CACNA1F.

BACKGROUND: Incomplete X-linked congenital stationary night blindness (CSNB) is a clinically variable condition that has been shown to be caused by mutations in the calcium-channel CACNA1F gene. We assessed the clinical variability in the expression of the incomplete CSNB phenotype in a subgroup of patients of Mennonite ancestry with the same founder mutation. METHODS: Sixty-six male patients from 15 families were identified with a common mutation in exon 27 of CACNA1F (L1056insC). Clinical variability in night blindness, reduced visual acuity, myopia, nystagmus and strabismus was examined. RESULTS: At least one of the major features of CSNB (night blindness, myopia and nystagmus) was absent in 72% of the patients. All the examined features varied widely, both between and within families. INTERPRETATION: Although the patients shared a common CACNA1F mutation, there was considerable variability in the clinical expression of the incomplete CSNB phenotype. These findings suggest the presence of other genetic factors modifying the phenotype of this disorder.

Adolescent↗
PubMedDate not supplied

Interleukin-7 gene transfer in non-small-cell lung cancer decreases tumor proliferation, modifies cell surface molecule expression, and enhances antitumor reactivity.

Cytokine gene transfer to tumor cells can augment host antitumor responses and modify tumor phenotype. To evaluate the immunoregulatory and antitumor capacities of lung tumor-derived interleukin-7 (IL-7), we transduced non-small-cell lung cancer (NSCLC) cell lines with the IL-7/HyTK internal ribosomal entry site (IRES) retroviral vector and evaluated modifications in tumor phenotype and cocultured effector activities. In vitro proliferation of IL-7-transduced tumor cells was significantly less than control vector-transduced and parental tumor cells. The decreased proliferation rates of IL-7-transduced cells could be reproduced by adding high concentrations of recombinant IL-7 to the parental cells. Anti-IL-7 monoclonal antibody significantly increased the proliferation of the IL-7-transduced cells (P < .05). Parental NSCLC cells were found to express the IL-7 receptor, and IL-7 gene transduction did not alter expression of the IL-7 receptor. IL-7 transduction significantly altered tumor cell expression of intracellular adhesion molecule 1, major histocompatibility complex 1, lymphocyte function-related antigen 3, very late activation antigen beta 1, and p185neu. Peripheral blood lymphocytes cocultured with either IL-7-transduced tumor cells or tumor supernatants had enhanced cytolytic and proliferative capacities compared with coculture with control vector-transduced or parental cells. Our findings indicate that IL-7 gene transfer in NSCLC significantly augments cocultured effector activities in vitro, inhibits tumor cell proliferation, and modifies tumor cell surface phenotype. These findings suggest that IL-7 gene therapy may be effective in modifying host antitumor responses in NSCLC.

Antibodies, Monoclonal↗
PubMed1999

[Analysis of the interaction of mutations at the Drosophila melanogaster Su(mg), mod(mdg4), and su(Hw) loci].

The mod(mdg4)1u1 mutation modifies the phenotypic expression of mutations induced by the MDG4 insertion. The Suppressor of modifier mdg4 (Su(mg)) gene family was described earlier. Most Su(mg) mutations completely suppressed the negative effect of the mod(mdg4)1u1 mutation on transcription of the yellow gene. However, only a few Su(mg) mutations suppressed the inhibiting effect of mod(mdg4)1u1 on transvection between the y59b/y2 alleles. The interaction of the mod(mdg4) and Su(mg) mutations with the su(Hw) mutation was studied. The phenotypic expression of the Su(mg) and mod(mdg4)1u1 mutations was shown to depend on the presence of the functional protein su(Hw).

Alleles↗
PubMed2002

Inactivation of the hemochromatosis gene differentially regulates duodenal expression of iron-related mRNAs between mouse strains.

BACKGROUND & AIMS: Hfe knockout mice, like patients with hereditary hemochromatosis, have augmented duodenal iron absorption and increased iron deposition in hepatic parenchymal cells. The goals of the present study were to gain further insight into the control of iron absorption by comparing the transcript levels of iron-related genes in the duodenum of DBA/2 Hfe-/- mice, susceptible to iron loading, and wild-type controls, and to test whether variations in the duodenal expression of these messengers contribute to the DBA/2 and C57BL/6 strain differences in the severity of hepatic iron loading. METHODS: Expression of the different transcripts was quantified by real-time polymerase chain reaction. RESULTS: The 2 strains differ strikingly, not only in the severity of hepatic iron loading, but also in the duodenal expression of iron-related genes. In DBA/2 Hfe-/- mice, increased intestinal iron absorption results from the concomitant up-regulation of the Dcytb, DMT1, and FPN1 messengers. No increase in the expression of these messengers is seen in C57BL/6 Hfe-/- mice. CONCLUSIONS: The up-regulation of these transcripts suggests that an inappropriate iron-deficiency signal is sensed by the duodenal enterocytes, leading to an enhanced ferric reductase activity and the increase of duodenal iron uptake and transfer to the circulation. The genes modifying the hemochromatosis phenotype probably act by modifying the expression of these 3 messengers.

Animals↗
PubMed2003

Effects of subepithelial fibroblasts on epithelial differentiation in human skin and oral mucosa: heterotypically recombined organotypic culture model.

The stratified squamous epithelia differ regionally in their patterns of morphogenesis and differentiation. Although some reports suggested that the adult epithelial phenotype is an intrinsic property of the epithelium, there is increasing evidence that subepithelial connective tissue can modify the phenotypic expression of the epithelium. The aim of this study was to elucidate whether the differentiation of cutaneous and oral epithelia is influenced by underlying mesenchymal tissues. Three normal skin samples and three normal buccal mucosa samples were used for the experiments. Skin equivalents were constructed in four ways, depending on the combinations of keratinocytes (cutaneous or mucosal keratinocytes) and fibroblasts (dermal or mucosal fibroblasts), and the effects of subepithelial fibroblasts on the differentiation of oral and cutaneous keratinocytes were studied with histological examinations and immunohistochemical analyses with anti-cytokeratin (keratins 10 and 13) antibodies. For each experiment, three paired skin equivalents were constructed by using single parent keratinocyte and fibroblast sources for each group; consequently, nine (3 x 3) organotypic cultures per group were constructed and studied. The oral and cutaneous epithelial cells maintained their intrinsic keratin expression. The keratin expression patterns in oral and cutaneous epithelia of skin equivalents were generally similar to their original patterns but were partly modified exogenously by the topologically different fibroblasts. The mucosal keratinocytes were more differentiated and expressed keratin 10 when cocultured with dermal fibroblasts, and the expression patterns of keratin 13 in cutaneous keratinocytes cocultured with mucosal fibroblasts were different from those in keratinocytes cocultured with cutaneous fibroblasts. The results suggested that the epithelial phenotype and keratin expression could be extrinsically modified by mesenchymal fibroblasts. In epithelial differentiation, however, the intrinsic control by epithelial cells may still be stronger than extrinsic regulation by mesenchymal fibroblasts.

Cell Differentiation↗
PubMed1995

Childhood onset cyclic neutropenia: G-CSF therapy restores neutrophil count but does not influence superoxide anion and cytokine release by neutrophils.

In this paper we describe the case of a 16-year-old boy with childhood onset cyclic neutropenia (CN) with a 21 d cycle who was successfully treated with recombinant granulocyte-colony stimulating factor (G-CSF). Cyclic therapy with G-CSF (5 micrograms/kg/d s.c. for 1 week every 21 d) maintained peripheral neutrophil count above the normal range, reduced the incidence of severe infections and significantly improved the patient's performance status throughout an 18-month follow-up. Phenotypic analysis of circulating lymphocytes demonstrated that G-CSF treatment does not modify the phenotypic profile of circulating B, T and NK cell populations. Circulating neutrophils released normal amounts of cytokines (including IL-1 beta, IL-8, TNF alpha) and superoxide anion during G-CSF therapy.

Adolescent↗
PubMedDate not supplied

[Multiple resistance of eukaryotic cells caused by P-glycoprotein].

Recent data concerning cloning and sequencing of mdr genes involved in multiple drug resistance in higher eukaryotes are reviewed. Structures of ABC-superfamily members, including the mdr products as well as mechanisms of their superproduction at various levels are considered. The possible role of MDR-transporter in normal tissues and various approaches to overcoming the MDR phenotype are discussed. Non-P-glycoprotein mechanisms of drug resistance capable to modify MDR phenotype and applications of mdr in biotechnology are provided.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Genotype/phenotype correlations of NPHS1 and NPHS2 mutations in nephrotic syndrome advocate a functional inter-relationship in glomerular filtration.

Mutations of the novel renal glomerular genes NPHS1 and NPHS2 encoding nephrin and podocin cause two types of severe nephrotic syndrome presenting in early life, Finnish type congenital nephrotic syndrome (CNF) and a form of autosomal recessive familial focal segmental glomerulosclerosis (SRN1), respectively. To investigate the mechanisms by which mutations might cause glomerular protein leak, we analysed NPHS1/NPHS2 genotype/phenotype relationships in 41 non-Finnish CNF patients, four patients with congenital (onset 0 to 3 months) focal segmental glomerulosclerosis and five patients with possible SRN1 (onset 6 months to 2 years). We clarify the range of NPHS1 mutations in CNF, detecting mutation 'hot-spots' within the NPHS1 coding sequence. In addition, we describe a novel discordant CNF phenotype characterized by variable clinical severity, apparently influenced by gender. Moreover, we provide evidence that CNF may be genetically heterogeneous by detection of NPHS2 mutations in some CNF patients in whom NPHS1 mutations were not found. We confirm an overlap in the NPHS1/NPHS2 mutation spectrum with the characterization of a unique di-genic inheritance of NPHS1 and NPHS2 mutations, which results in a 'tri-allelic' hit and appears to modify the phenotype from CNF to one of congenital focal segmental glomerulosclerosis (FSGS). This may result from an epistatic gene interaction, and provides a rare example of multiple allelic hits being able to modify an autosomal recessive disease phenotype in humans. Our findings provide the first evidence for a functional inter-relationship between NPHS1 and NPHS2 in human nephrotic disease, thus underscoring their critical role in the regulation of glomerular filtration.

Adult↗
PubMed1992

Modification of the dystrophic phenotype after transient neonatal denervation: role of MHC isoforms.

While it recently has been demonstrated that it is possible to modify the phenotypic expression of murine dystrophy (dy/dy) (i.e., prevent myofiber loss) by subjecting the extensor digitorum longus (EDL) muscle of 14-day-old dy/dy mice to transient neonatal denervation (Moschella and Ontell, 1987), the mechanism responsible for this phenomenon has not been determined. Since it has been suggested that the effects of dystrophy vary according to fiber type, the fiber type frequency in 100-day-old normal (+/+) and dy/dy EDL muscles subjected to transient neonatal denervation has been determined by immunohistochemical analysis of their myosin heavy chain (MHC) composition. This frequency has been compared with that found in the EDL muscles of 14- and 100-day-old unoperated +/+ and dy/dy mice, in order to determine whether the reinnervation of transiently denervated neonatal muscle results in a preponderance of fibers of the type that might be spared dystrophic deterioration. In unoperated dy/dy muscle there is a progressive decrease in the frequency and in the absolute number of fibers that express MHC2B, with 100-day-old dy/dy muscles having approximately 32% of the number of myofibers fibers containing MHC2B as is found in age-matched +/+ muscles. The number of fibers containing the other fast isoforms (MHC2A and MHC2X) is similar in +/+ and dy/dy muscles at this age, indicating that fibers with MHC2B are most affected by the dystrophic process. Reinnervation following transient neonatal denervation of both the +/+ and the dy/dy EDL muscles results in a similar decrease (approximately 62%) in the number of myofibers containing MHC2B and an increase in myofibers containing the other fast MHC isoforms (MHC2A and MHC2X). The selective effect of dy/dy on fibers containing MHC2B and the sparing of myofibers in transiently denervated dy/dy muscle (which contains a reduced frequency of fibers containing MHC2B) are consistent with, although not direct proof of, the hypothesis that alterations in the fiber type may play a role in the failure of myofibers in transiently denervated dy/dy muscles to undergo dystrophic deterioration. Evidence is presented suggesting that neurons that supply myofibers containing MHC2B may be at a selective disadvantage in their ability to reinnervate neonatally denervated muscles.

Animals↗
PubMed1977

Salivary peroxidase (SAPX): genetic modification and relationship to the proline-rich (Pr) and acidic (Pa) proteins.

There is genetic polymorphism of the peroxidase of human saliva, but not of leukocytes. The phenotypes are determined by autosomal inheritance, the phenotype of fast mobility (SAPX 1) being determined by homozygosity for a recessive gene (SAPX1) and the phenotypes of slow mobility (SAPX 2 and SAPX 3) being determined by two different genes, SAPX2 and SAPX3, with completely dominant expression at the same locus. The phenotypes are modified by varying degrees of endogenous proteolysis. The SAPX 2 and SAPX 3 types appear to be genetically controlled modifications of SAPX 1 rather than different primary gene products, because of their completely dominant inheritance, their larger molecular size compared to SAPX 1, and their dissociation with 2-mercaptoethanol to give SAPX 1. The acidic protein type Pa 1 is always found in association with SAPX 2, and an uncommon variant type Pa 2 is associated with SAPX 3. The most likely hypothesis is that the genes Pa1 and Pa2 produce products which modify the SAPX 1 type. When the Pa type is Pa 0, the SAPX phenotype is SAPX 1. Since 2-mercaptoethanol can dissociate the Pa 1 protein into a probable monomeric form, and can dissociate SAPX 2 and SAPX 3 to give SAPX 1, it is probable that Pa 1 and Pa 2 monomers complex with SAPX 1 through disulfide bonds to give SAPX 2 or SAPX 3 types. The frequencies of the genes determining the SAPX types are the same as those for Pa: SAPX1 and Pa0 = 0.787, SAPX2 and Pa1 = 0.208, SAPX3 and Pa2 = 0.005.

Electrophoresis, Polyacrylamide Gel↗