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P Cullen

Publications and source records attributed to P Cullen.

At least 73 records · Page 4Linked to original sources
PubMed1997

Regulation of human monocyte apoptosis by the CD14 molecule.

Bacterial products such as LPS have been shown to activate monocytes and to increase CD14 expression, while anti-inflammatory cytokines, i.e., IL-4, down-regulate CD14. Furthermore, activation of monocytes increases survival, whereas deactivation evokes apoptosis (programmed cell death, PCD). This correlation among activation, CD14 expression, and the lifespan of the cells prompted us to investigate the role of CD14 in monocyte apoptosis. The effects of LPS and IL-4 on the expression of CD14, indicated by binding of Leu M3 Ab, and PCD of monocytes were studied simultaneously and in a kinetic fashion by multiparameter flow cytometry. Monocyte PCD was determined by binding of FITC-conjugated annexin V, which indicates apoptotic cell death in early stages, and was confirmed using well-established detection methods, i.e., DNA electrophoresis, electron microscopy, or colorimetric DNA staining. The present study shows that the LPS-induced increase in CD14 expression rescued monocytes from apoptosis, whereas IL-4 treatment first down-regulated CD14 expression and consecutively evoked apoptosis. CD14-/annexin V- monocytes were not apoptotic as confirmed by DNA electrophoresis, whereas CD14-/ annexin V+ monocytes showed clear apoptotic features. Kinetic studies ruled out that monocytes first bound annexin V and later lost the CD14 Ag. Other molecules, such as HLA-A, -B, and -C Ags, were not down-regulated during apoptosis. Enzymatic removal of membrane-bound CD14 by phosphatidylinositol-specific phospholipase C evoked PCD similarly to IL-4. These results suggest that regulation of CD14 receptor expression is an early effector mechanism mediating life or death of monocytes. Down-regulation or removal of the receptor triggers apoptosis, whereas up-regulation promotes survival.

Annexin A5↗
PubMed1997

Measuring cholesterol in macrophages: comparison of high-performance liquid chromatography and gas-liquid chromatography with enzymatic fluorometry.

Cholesterol and cholesteryl esters in human macrophages were analyzed by three different methods. Values obtained by high-performance liquid chromatography and by gas-liquid chromatography were compared with those obtained using enzymatic fluorometry. We also assessed fractional lipid recovery from these cells using radiolabeled cholesterol and cholesteryl ester. Enzymatic fluorometry substantially underestimated cellular cholesterol content. Two reasons for this were found. First, recovery into a variety of solvents was incomplete, particularly when extracted lipids were dried and redissolved in a second solvent. Second, the cells appeared to contain an intrinsic inhibitor of the enzymatic fluorometric method.

Cells, Cultured↗
PubMed1997

New and classical risk factors--the Münster heart study (PROCAM).

A total of 4,849 male participants of the prospective cardiovascular Münster Study (PROCAM), aged 40 - 65 years underwent extensive screening for cardiovascular risk factors before 1986 and were subsequently followed up for at least 8 years. During this time 189 non-fatal and 49 fatal myocardial infarctions occurred, 28 men suffered a sudden cardiac death and 169 persons died of other causes. Using multivariate statistical methods we confirmed that age, increased LDL cholesterol levels, decreased HDL cholesterol levels, high blood pressure, cigarette smoking, diabetes mellitus, angina pectoris and a positive family history are important risk factors for a myocardial infarction or cardiac death. The results of the PROCAM Study demonstrate that elevated triglycerides are an independent risk factor for an early myocardial infarction or cardiac death. Using a multiple logistic function analysis an algorithm for the assessment of the global risk was derived from the data. The observed incidence of coronary heart disease rises sharply as the global risk increases, thus permitting the use of this algorithm in clinical practice for the assessment of the individual risk of myocardial infarction. Risk factors such as lipoprotein(a) and coagulation factors may improve the predictive value of this algorithm. Furthermore it is expected that the exploration of genetic defects will strongly increase the predictive value and precise determination of individual risk.

Adult↗
PubMed1997

Membrane association, localization and topology of rat inositol 1,4,5-trisphosphate 3-kinase B: implications for membrane traffic and Ca2+ homoeostasis.

We previously reported the isolation of a rat cDNA clone encoding a protein with significant sequence homology to the B isoform of human myo-inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase B); this protein was thus designated rat IP3 3-kinase B [Thomas, Brake, Luzio, Stanley and Banting (1994) Biochim. Biophys. Acta 1220, 219-222]. However, no IP3 kinase isoform had been shown to generate the physiologically important isoform of inositol tetrakisphosphate, i.e. inositol 1,3,4,5-tetrakisphosphate. We now present direct evidence that the putative rat IP3 3-kinase B is genuinely an IP3 3-kinase. We also show that the enzyme exists both as a peripheral membrane protein tightly associated with the cytosolic face of the extended endoplasmic reticulum network, and as a cytosolic protein. Association of the IP3 3-kinase with membranes is not affected by treatment with brefeldin A, Na2CO3 (pH 11.5), 2 M NaCl, or alteration of [Ca2+]. However, treatment of isolated membranes with 4 M urea leads to dissociation of the kinase from the membrane, implying that membrane association involves specific, conformation-dependent protein-protein interactions. The fact that IP3 3-kinase B is localized exclusively to membranes of Ca2+ stores, is consistent with a model where this kinase plays a role in IP3-dependent Ca2+ release.

Amino Acid Sequence↗
PubMed1997

Secretion of brain natriuretic peptide in patients with aneurysmal subarachnoid haemorrhage.

BACKGROUND: Subarachnoid haemorrhage is commonly associated with natriuresis and hyponatraemia. One possible explanation for these features is a defect in the central regulation of renal sodium reabsorption with increased secretion of a natriuretic factor. We investigated whether excess sodium secretion in patients with subarachnoid haemorrhage is related to increased secretion of natriuretic peptides or to the presence of digoxin-like immunoreactive substances. METHODS: We measured the plasma concentrations of digoxin-like immunoreactive substances (by a fluorescence polarisation immunoassay) and natriuretic peptides, aldosterone, renin, and antidiuretic hormone (by radioimmunoassay) in ten patients with aneurysmal subarachnoid haemorrhage, ten patients undergoing elective craniotomy for cerebral tumours, and 40 healthy controls of similar age and sex distribution. Samples were collected before surgery, 1 h, 4 h, and 12 h after surgery, then daily until 7 days postoperatively in the two groups of patients. FINDINGS: All patients with subarachnoid haemorrhage, but none of the tumour patients, showed increased urine output and urinary excretion of sodium (p = 0.018 for comparison of means of curves to 7 days). The patients with subarachnoid haemorrhage had much higher plasma concentrations of brain natriuretic peptide (BNP) than controls, on admission (mean 15.1 [SE 3.8] vs 1.6 [1.0] pmol/L, p < 0.001) and throughout the study period, accompanied by lower than normal aldosterone concentrations and normal plasma concentrations of atrial and C-type natriuretic peptides (ANP, CNP). The patients with tumours had similar plasma concentrations of ANP, BNP, and CNP to the controls. We did not detect digoxin-like immunoreactive substances in either group of patients. INTERPRETATION: Salt-wasting of central origin may induce hyponatraemia in patients with aneurysmal subarachnoid haemorrhage, possibly as a result of increased secretion of BNP with subsequent suppression of aldosterone synthesis.

Brain Neoplasms↗
PubMed1997

Downregulation of the selectin ligand-producing fucosyltransferases Fuc-TIV and Fuc-TVII during foam cell formation in monocyte-derived macrophages.

Identification of genes expressed during foam cell formation is important for understanding the molecular basis of atherosclerosis. We used polymerase chain reaction (PCR)-based differential display to isolate differentially expressed cDNA species in foam cells induced by incubation of human monocyte-derived macrophages in the presence of acetylated or oxidized LDL. This led to identification of a 306-bp cDNA with 100% homology to type IV fucosyltransferase (Fuc-TIV), which was downregulated by factors of 20 and 3 in acetylated LDL- and oxidized LDL-loaded macrophages, respectively. This enzyme is sufficient for the expression of Lewis X and sialyl Lewis X, carbohydrate adhesion molecules that bind to receptors of the selectin family. Expression of a second fucosyltransferase (Fuc-TVII) that synthesizes sialyl Lewis X but not Lewis X was shown by quantitative reverse transcription-PCR to also be reduced, by 40% and 20% in acetylated LDL- and oxidized LDL-loaded macrophages, respectively. alpha-(1,3)-Fucosyltransferase enzyme activity was reduced in lysates from both acetylated LDL- and oxidized LDL-loaded cells. Analysis by flow cytometry showed reduced expression of the CD15 (corresponding to Lewis X) and CD15s (sialyl Lewis X) antigens on the surface of cells loaded with either acetylated or oxidized LDL. Transformation of macrophages into foam cells results in reduced expression of selectin-binding ligands on the surface of such cells.

Acetylation↗
PubMed1997

Lipoproteins and cardiovascular risk-from genetics to CHD prevention.

Dyslipidemia is said to be present when lipid or lipoprotein levels lie within a range which is known from epidemiological studies to be associated with secondary complications, in particular atherosclerosis of the coronary arteries, or when a lipid or lipoprotein grossly deviates from the norm as in abetalipoproteinemia, hypobetalipoproteinemia or the HDL deficiency syndromes. In most cases, dyslipidemia is due not to a single genetic or environmental factor, but to a combination of the effects of several genes of small effect (polygenes) and environment. In other cases, however, dyslipidemia is caused by a mutation in a single gene of large effect. In such cases, the extent and nature of the phenotype depends primarily on the identity of the gene involved, but is also modulated to an important degree by the nature of the mutation and the genetic and environmental background against which this mutation occurs. In addition, many cases of hyperlipidemia are secondary to other disorders such as hypothyroidism or renal dysfunction. Such disorders may also unmask or exacerbate a genetic lipoprotein disorder. Examples of the latter are the unmasking of type III hyperlipidemia by diabetes mellitus or the exacerbation of familial hypercholesterolemia by hypothyroidism.

Clinical Trials as Topic↗
PubMed1997

An improved method for quantification of cholesterol and cholesteryl esters in human monocyte-derived macrophages by high performance liquid chromatography with identification of unassigned cholesteryl ester species by means of secondary ion mass spectrometry.

The measurement of cholesteryl esters in human monocyte-derived macrophages using previously described high performance liquid chromatography methods is hampered by the presence in these cells of large amounts of triglycerides. We present a simple reversed phase high performance liquid chromatography protocol for quantification of cholesterol and cholesteryl esters in human monocyte/macrophages or other triglyceride-rich cells. Our method requires only lipid extraction and hydrolysis of triglycerides using a solution of ethanolic potassium hydroxide and is of sufficient sensitivity to allow measurement in 10(5) cells. Use of this protocol led to the isolation of eight previously unassigned cholesteryl ester peaks comprising 16% of the total cholesteryl ester content of human monocyte-derived macrophages. Using time-of-light secondary ion mass spectrometry and synthesized authentic standards, seven of these peaks were found to comprise cholesterol esterified with polyunsaturated n-3 (omega 3) (cholesteryl eicosapentaenoate, docosatrienoate, docosapentaenoate, and docosahexaenoate) and n-6 (omega 6) (cholesteryl docosatetraenoate, eicosadienoate, and eicosatrienoate) fatty acids. The remaining peak was shown to be the cholesteryl ester of n-7 (omega 7) palmitoleic acid by comparison with a commercially available standard. The identification of all the cholesteryl esters in cholesterol-loaded human monocyte-derived macrophages will assist future studies of lipid metabolism in these cells.

Animals↗
PubMed1997

Sexual relationships in married dementia sufferers.

OBJECTIVE: To determine the proportion of couples, one of whom suffers from dementia, continuing with a sexual relationship, their level of satisfaction with their sexual relationship and the associations of remaining sexually active. DESIGN: A survey of married couples enrolled in a prospective dementia study. SETTING: Psychiatric services and a memory clinic. SAMPLE: The partners of 47 married patients with mild to moderate dementia. MEASURES: The assessment included the GMS/HAS/SDS package, the Marital Intimacy Scale (with some additional questions regarding sexual relations), the CAMCOG, the Carers Stress Scale, the Cornell Depression Scale and the Burns Symptom Checklist. Dementia was diagnosed according to DSM-III-R, McKhann, McKeith, Hachinski and HAS AGECAT criteria. RESULTS: Forty partners completed the study. Nine (22.5%) continued to have a sexual relationship, all of whom were satisfied with the situation. Twelve (38.7%) of the carers who were not sexually active were dissatisfied with the absence of a sexual relationship. There was a trend for male carers to be more likely to be involved in a continuing sexual relationship. Dissatisfaction with the absence of a sexual relationship was significantly associated with a diagnosis of vascular dementia in the patient and showed a trend towards an association with younger patient age. CONCLUSIONS: Nearly a quarter of married dementia sufferers are involved in a continuing sexual relationship, emphasizing the importance of further research in this area.

Aged↗
PubMed1997

Eating disorders in dementia.

OBJECTIVES: To examine the prevalence and associations of altered eating patterns in dementia sufferers. DESIGN: Prospective cohort study. SETTING: Psychiatric services and a memory clinic. SAMPLE: 124 patients with DSM-III-R dementia. MEASURES: The Geriatric Mental State Schedule, the History and Aetiology Schedule, the Cornell Depression Scale and the CAMCOG. Additional standardized questions were asked about eating patterns in the month prior to the study. RESULTS: Information concerning eating patterns was obtained from 105 of the 124 patients: 21% had increased food consumption, 22.1% had decreased food consumption, 2.9% tried to eat inedible substances, 11.4% had an increased preference for sweet things, 7.6% became more fussy about their food choices and 4.8% became less fussy. Decreased food consumption was significantly associated with less severe cognitive impairment and was related to RDC major depression in some patients. An increased preference for sweet things showed an association with a diagnosis of Alzheimer's disease. Increased food consumption was probably heterogeneous. Neither increased food consumption nor an increased preference for sweet foods was associated with the severity of cognitive impairment. CONCLUSION: Altered eating patterns are common in dementia sufferers.

Aged↗
PubMed1996

Inositol phosphates - whither bound? Intracellular signalling.

Many proteins are being found to bind inositol phosphates with varying degrees of specificity; the variety of domains that can bind inositol phosphates suggests convergent evolution, but the functions of most of the binding sites are not yet clear.

Amino Acid Sequence↗
PubMed1996

c-erb B-2 and p53 expression in breast cancer fine needle aspirates.

The aim of this study was to co-evaluate c-erb B-2 and p53 protein expression in breast cancer fine needle aspirates (FNA) and to compare this with histological variables and the immunohistochemical phenotype of the tumours. Furthermore, we assessed the relationship of c-erb B-2 and p53 immunocytochemical expression to tumour prognostic factors. We examined 124 breast cancer FNAs and 79 matched surgical specimens using the avidin-biotin complex (ABC) and the alkaline phosphatase immunocytochemical techniques. C-erb B-2 immunopositivity was detected in 37.9% of the FNAs, while 31.7% were positive for p53. A statistically significant correlation was observed between p53 negativity and absence of c-erb B-2 immunostaining in the FNAs (P = 0.0007). Smears from infiltrating ductal carcinomas tended to be more frequently positive for p53 (36.7%) than those from lobular carcinomas (11.7%) (P = 0.054). In matched tumour tissues, c-erb B-2 was positive in 16.7% and p53 in 19% of cases. The immunocytochemical results for both c-erb B-2 and p53 were significantly correlated with the immunohistochemical results. There was no correlation between c-erb B-2 and p53 immunostaining, in both FNAs and tissues, and patients menopausal status, tumour size, grade and lymph node status.

Adult↗
PubMed1996

Hemostatic variables in the prediction of coronary risk: results of the 8 year follow-up of healthy men in the Münster Heart Study (PROCAM). Prospective Cardiovascular Münster Study.

Myocardial infarction is usually due to the acute formation of an occlusive thrombus within the coronary arteries, in most cases against a background of pre-existing coronary atherosclerosis. Both of these factors may be promoted by a procoagulant state of the hemostatic system. Plasma fibrinogen, factor VIIc, blood pressure, and lipid parameters were measured in 2,781 healthy men aged 40-65 in the Münster Heart Study (formerly known as the PROCAM Study). After 8 years of follow-up 130 coronary events (15 sudden cardiac deaths, 22 fatal myocardial infarctions, and 93 nonfatal myocardial infarctions) were observed. Plasma fibrinogen concentration and factor VIIc activity were significantly greater among men who suffered a coronary event. The mean plasma fibrinogen level of the event group exceeded that of the non-event group by 0.32 g/l [2.59 +/- 0.58 vs. 2.91 +/- 0.58 (mean +/- SD) respectively, P < 0.001]. The incidence of coronary events among men within the upper tertile of fibrinogen concentration was three times higher than among men within the lower tertile. Plasma factor VIIc activity was 112.4 +/- 20.1% in the event group and 108.7 +/- 21.4% in the non-event group (P < 0.05). Among men in the upper tertile of factor VIIc activity, the incidence of coronary events was 1.6 times that of men in the lower tertile. When fibrinogen and low density lipoprotein (LDL) concentration were considered together, there was a graded and dramatic eightfold increase in 8 year risk from 17 per 1,000 of population among men with both fibrinogen and LDL cholesterol in the lower tertiles to 130 per 1,000 in men with both of these parameters in the upper tertile. In men with LDL cholesterol in the lowest tertile, increasing fibrinogen levels did not increase the risk of a coronary event. The coagulation variables, fibrinogen concentration, and factor VIIc activity thus markedly improve our ability to predict coronary risk.

Adult↗