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Biomedical subjects

S Cooper

Publications and source records attributed to S Cooper.

At least 55 records · Page 3Linked to original sources

Adverse effects of oral corticosteroids in relation to dose in patients with lung disease.

BACKGROUND: The adverse effects of oral corticosteroids are widely recognised but there are few quantitative data on which to base advice to patients. In a two part cross sectional study we compared adverse effects in patients with lung disease taking oral corticosteroids and control subjects and related the adverse effects to corticosteroid dose in the patient group. METHODS: Data on oral corticosteroid use, lifestyle, fractures, and other possible adverse effects were collected by questionnaire and compared between a community based cohort of patients taking continuous or frequent intermittent oral corticosteroids for asthma, chronic obstructive pulmonary disease, or alveolitis and age and sex matched control subjects. Dose related effects were explored in the corticosteroid group using cumulative dose quartiles and multiple logistic regression. RESULTS: A total of 367 patients (> or = 50 years, 48% female) and 734 control subjects completed the questionnaire. The cumulative incidence of fractures since the time of diagnosis was 23% for patients taking oral corticosteroids and 15% in the control group (odds ratio (OR) 1.8; 95% confidence interval (CI) 1.3 to 2.6). Patients were more likely to have had a fracture of the vertebrae (OR 10; 95% CI 2.9 to 34), hip (OR 6; 95% CI 1.2 to 30), and ribs or sternum (OR 3.2, 95% CI 1.6 to 6.6) than control subjects. They also reported a significant increase in cataracts, use of antacids, muscle weakness, back pain, bruising, oral candidiasis, and having fewer teeth. The effects of oral corticosteroids were dose related: the odds ratio for patients in the highest compared with the lowest cumulative dose quartile (median prednisolone dose 61 g versus 5 g) ranged from 2 for all fractures to 9 for vertebral fractures and bruising. CONCLUSIONS: By quantifying the morbidity associated with the use of oral corticosteroids, this study should help to rationalise their long term use.

Administration, Oral↗

Onset of analgesia for liquigel ibuprofen 400 mg, acetaminophen 1000 mg, ketoprofen 25 mg, and placebo in the treatment of postoperative dental pain.

Ibuprofen is a peripherally acting nonsteroidal anti-inflammatory drug indicated fo ranalgesia, antipyresis, and various arthritic conditions. A solubilized 200 mg liquigel formulation of ibuprofen has been shown to have a more rapid rate of absorption compared with ibuprofen 200 mg tablets. Ibuprofen liquigels have a kinetic profile similar to ibuprofen suspension, with both a higher Cmax and an earlier tmax than any solid tablet. The objective of this single-dose, double-blind, triple-dummy, parallel-group study was to assess the time to onset of relief and overall analgesic efficacy of liquigel ibuprofen 400 mg, ketoprofen 25 mg compared with acetaminophen 1000 mg, and placebo in 239 patients with moderate or severe pain following third molar extractions. Treatments were compared over 6 hours using standard scales for pain intensity and relief and stopwatch onset of meaningful relief. All active treatments provided meaningful relief significantly faster compared with placebo. Ibuprofen provided significantly faster relief compared with acetaminophen and ketoprofen. By the end of the study (6 h), onset of meaningful relief was achieved by 36%, 99%, 96%, and 88% of the patients in the placebo, ketoprofen, ibuprofen, and acetaminophen groups, respectively. The median times to onset of relief were > 6 hours for placebo, 25.5 minutes for ketoprofen, 24.2 minutes for ibuprofen, and 29.9 minutes for acetaminophen. In addition, both ibuprofen and ketoprofen showed statistical superiority over acetaminophen at earlier time points on the time-effect curves for pain relief and pain intensity difference. Consistent results were seen with respect to the 6-hour summary efficacy variables: the three active treatments were significantly better than placebo, and ibuprofen was significantly better than both acetaminophen and ketoprofen. Liquigel ibuprofen 400 mg was shown to provide faster relief and superior overall efficacy compared with ketoprofen 25 mg, acetaminophen 1000 mg, and placebo. No serious adverse effects were reported in this single-dose study.

Abdominal Pain↗

Influence of psychiatric disorder on the controlling behaviour of mothers with 1-year-old infants. A study of women with maternal eating disorder, postnatal depression and a healthy comparison group.

BACKGROUND: Certain styles of parental controlling behaviour influence child development. Work with mothers with eating disorders suggests that they may be particularly controlling of their infants. AIMS: To examine the nature and specificity of maternal controlling behaviour in mothers with eating disorders compared with mothers who had experienced postnatal depression and a healthy comparison group. METHOD: Mothers with eating disorders (n=34), postnatal depression (n=39) and a healthy comparison group (n=61) and their 12-month-old infants were observed during play and mealtimes, and blind ratings made of verbal and non-verbal control exerted by the mother. RESULTS: Mothers in the eating disorder group used more verbal control, especially strong control. There were no differences between the groups on gentle verbal control and physical contact. Maternal dietary restraint was the one feature of eating disorder psychopathology associated with the use of verbal control. Marital criticism was also associated with the extent of verbal controlling behaviour. CONCLUSIONS: Aspects of maternal control of infants were found to be specific to maternal eating disorder psychopathology.

Analysis of Variance↗

Endoscopic gastrointestinal manifestations of liver disease.

Esophageal and gastric varices are common manifestations of advanced chronic liver disease, but other endoscopic gastrointestinal manifestations of portal hypertension may occur. In the upper gastrointestinal tract, portal hypertensive gastropathy, particularly when severe, and gastric antral vascular ectasias are important alternative causes of gastrointestinal bleeding. Portal hypertensive enteropathy is an uncommon source of gastrointestinal bleeding, and its overall clinical significance remains unknown. In the lower gastrointestinal tract, portal hypertension may be associated with hemorrhoids, anorectal varices, and portal hypertensive colopathy, all of which are occasional causes of gastrointestinal bleeding.

Chronic Disease↗

Fc-receptor dependent platelet aggregation induced by monoclonal antibodies against platelet glycoprotein Ib or von Willebrand factor.

In this paper we describe two pathways leading to platelet activation by crosslinking glycoprotein (GP) Ibalpha to the platelet Fc-receptor (FcgammaRII). First the monoclonal antibody (MoAb) 9C8, raised against human platelet GPIbalpha, dose-dependently induced platelet aggregation of citrate-anticoagulated platelet-rich plasma, an effect that can be inhibited by several activation inhibitors. The FcgammaRII-inhibitory MoAb IV.3 was able to prevent the aggregatory effects of MoAb 9C8, indicating that crosslinking of the antigen GPIbalpha to the FcgammaII-receptor is necessary for the activating effect. Secondly we observed a synergistic activating effect of two anti-von Willebrand factor (vWF) MoAbs IC1E7 and B724, both known to enhance vWF binding to GPIbalpha in the presence of shear or ristocetin. When these antibodies are added together to PRP, platelet aggregation is induced without further need for an additional modulator. This effect can be blocked by either MoAb IV.3 or an inhibitory anti-GPIb MoAb, indicating that again the platelet activation results from signaling through FcgammaRII crosslinked to vWF bound to GPIbalpha. In addition, both the anti-GPIb MoAb 9C8, or the two anti-vWF MoAbs 1C1E7 and B724 induce genuine platelet activation, as evidenced by the secretion of ATP and protein tyrosine phosphorylation. These findings with both anti-GPIb and anti-vWF MoAbs add further proof to recent reports demonstrating an interaction between the platelet receptors GPIb and FcgammaRII, suggesting a role for the FcgammaII-receptor in GPIb-related signaling.

Adenosine Triphosphate↗

Antitumor activity of antisense clusterin oligonucleotides is improved in vitro and in vivo by incorporation of 2'-O-(2-methoxy)ethyl chemistry.

Phosphorothioate (P=S) antisense oligonucleotides (ASO) targeting the cell survival gene clusterin synergistically enhance castration- and chemotherapy-induced apoptosis in prostate cancer xenografts. This study compares efficacy, tissue half-lives, and toxicity of P=S clusterin ASO to third-generation backbone 2'-O-(2-methoxy)ethyl (2'MOE) ribose-modified clusterin ASO. Northern analysis quantified changes in clusterin mRNA levels in human PC-3 cells and tumors. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay measured effects of combined clusterin ASO plus paclitaxel on PC-3 cell growth. Athymic mice bearing PC-3 tumors were treated with paclitaxel plus either P=S clusterin ASO, 2'-MOE clusterin ASO, or mismatch control oligonucleotides for 28 days. Weekly body weights and serum parameters were measured to assess toxicity. Tissue half-life of P=S and 2'-MOE ASO in PC-3 tumors was assessed using capillary gel electrophoresis (CGE). Both 2'-MOE and P=S ASO decreased clusterin mRNA levels in a dose-dependent and sequence-specific manner. 2'-MOE ASO more potently suppressed clusterin mRNA (80 versus 40% at 500 nM) compared with P=S ASO. IC(50) of paclitaxel was equally reduced (50--75%) by both compounds. In vivo tissue half-life was significantly longer for 2'-MOE-modified ASO than for P=S ASO (5 versus 0.5 days). Using CGE, >90% of detected 2'-MOE ASO in tumor tissue was full length. Weekly administration of 2'-MOE clusterin ASO was equivalent to daily P=S clusterin ASO in enhancing paclitaxel efficacy in vivo. 2'-MOE-modified ASO potently suppressed clusterin expression and prolonged tissue half-lives with no additional side effects. These results support the use of 2'-MOE-modified ASO over conventional P=S ASO by potentially increasing potency and allowing longer dosing intervals in clinical trials.

Animals↗

The relationship between dialysate protein loss and membrane transport status in peritoneal dialysis patients.

Peritoneal dialysis (PD) patients lose significant quantities of protein and albumin during the dialysis procedure. The losses are greater in high transporters. The aim of the present study was to investigate the relationship between peritoneal membrane transport characteristics and protein losses. We studied 33 PD patients [14 men, 19 women; mean age: 53.5 years (range: 21-80 years)]. Fourteen patients had diabetes, and 22 were on automated PD. Dialysis adequacy was good, with a mean Kt/V of 2.63 (range: 1.51-4.89). Patients underwent a standard peritoneal equilibration test (PET). In addition, dialysate albumin (Alb) and protein (Pro) were measured at 0, 1, 2, and 4 hours, after lack of interference from unspent dialysate was ensured. Of the 33 patients, 23 were high or high-average transporters [based on 4-hour dialysate-to-plasma ratio of creatinine (D/PCr > or = 0.65)]. Protein losses owing to PD ranged from 3.5 g/day to 13.2 g/day (median: 5.9 g/day), of which 1.9-7.14 g/day (median: 3.21 g/day) was albumin. The 4-hour D/PCr correlated with the 4-hour D/PAlb (r = 0.62, p < 0.01), and 4-hour D/PPro (r = 0.63, p < 0.01). This finding persisted after correction for volume, indicating that it was not simply a concentration effect. The 4-hour D/PAlb and 4-hour D/PPro also correlated with the 24-hour PD albumin and protein losses. These results suggest a strong association between D/PCr and D/P for proteins. This observation is consistent with the increased protein losses through PD in high transporters and may be related to the inferior outcomes in this group.

Adult↗

MHC I-dependent antigen presentation is inhibited by poliovirus protein 3A.

The effects of poliovirus 3A protein expression and poliovirus infection on the presentation of hepatitis C virus antigens in cultured chimpanzee cells were examined. Expression of poliovirus 3A protein inhibits protein secretion when expressed in isolation and was sufficient to protect chimpanzee cells from lysis by hepatitis C virus-specific cytotoxic T cells in standard (51)Cr-release assays. Poliovirus infection also inhibited antigen presentation, as determined by decreased cytotoxic T cell activation. A mutation in 3A that abrogates the inhibition of protein secretion also abolished the effects of poliovirus on antigen presentation. These results demonstrate that the inhibition of secretion observed in poliovirus-infected cells substantially reduces the presentation of new antigens on the cell surface. These observations may reflect a general mechanism by which nonenveloped viruses such as poliovirus and other viruses that do not require a functional protein secretory apparatus can evade detection by the cellular immune response.

Animals↗

Essential role of signal transducer and activator of transcription (Stat)5a but not Stat5b for Flt3-dependent signaling.

The receptor tyrosine kinase Flt3 plays an important role in proliferation and survival of hematopoietic stem and progenitor cells. Although some post-receptor signaling events of Flt3 have been characterized, the involvement of the Janus kinase/signal transducer and activator of transcription (Jak/Stat) pathway in Flt3 signaling has not been thoroughly evaluated. To this aim, we examined whether Flt3 activates the Jak/Stat pathway in Baf3/Flt3 cells, a line stably expressing human Flt3 receptor. Stat5a, but not Stats 1-4, 5b, or 6, was potently activated by Flt3 ligand (FL) stimulation. Interestingly, FL did not activate any Jaks. Activation of Stat5a required the kinase activity of Flt3. A selective role for Stat5a in the proliferative response of primary hematopoietic progenitor cells to FL was documented, as FL did not act on progenitors from marrows of Stat5a(-/-) mice, but did stimulate/costimulate proliferation of these cells from Stat5a(+/+), Stat5b(-/-), and Stat5b(+/+) mice. Thus, Stat5a is essential for at least certain effects of FL. Moreover, our data confirm that Stat5a and Stat5b are not redundant, but rather are at least partially distinctive in their function.

Animals↗

The exodus subfamily of CC chemokines inhibits the proliferation of chronic myelogenous leukemia progenitors.

Chemokines are a family of related proteins that regulate leukocyte infiltration into inflamed tissue and play important roles in disease processes. Among the biologic activities of chemokines is inhibition of proliferation of normal hematopoietic progenitors. However, chemokines that inhibit normal progenitors rarely inhibit proliferation of hematopoietic progenitors from patients with chronic myelogenous leukemia (CML). We and others recently cloned a subfamily of CC chemokines that share similar amino-terminal peptide sequences and a remarkable ability to chemoattract T cells. These chemokines, Exodus-1/LARC/MIP-3alpha, Exodus-2/SLC/6Ckine/TCA4, and Exodus-3/CKbeta11/MIP-3beta, were found to inhibit proliferation of normal human marrow progenitors. The study described here found that these chemokines also inhibited the proliferation of progenitors in every sample of marrow from patients with CML that was tested. This demonstration of consistent inhibition of CML progenitor proliferation makes the 3 Exodus chemokines unique among chemokines. (Blood. 2000;95:1506-1508)

Cell Division↗

The continuum model and G1-control of the mammalian cell cycle.

The continuum model of the mammalian division cycle proposes that there are no G1-phase specific controls or events. The G1 phase is simply the time when processes begun in the previous cell cycle are completed. In this review, the continuum model is applied the variability of the G1-phase, the existence of G1-less cells, the ubiquitous G1-phase arrest phenomenon, the effect of over-expressed cyclins on G1-phase length, the statistical variation of the cell cycle, the reports of G1-phase syntheses, the proposed variation in retinoblastoma protein phosphorylation in G1-phase, and the myriad findings put forward to support the G1-control model of the mammalian division cycle. The continuum model is a valid description of the mammalian division cycle.

Animals↗

Common chimpanzees have greater diversity than humans at two of the three highly polymorphic MHC class I genes.

MHC class I polymorphism improves the defense of vertebrate species against viruses and other intracellular pathogens. To see how polymorphism at the same class I genes can evolve in different species we compared the MHC-A, MHC-B, and MHC-C loci of common chimpanzees and humans. Diversity in 23 Patr-A, 32 Patr-B, and 18 Patr-C alleles obtained from study of 48 chimpanzees was compared to diversity in 66 HLA-A, 149 HLA-B, and 41 HLA-C alleles obtained from a study of over 1 million humans. At each locus, alleles group hierarchically into families and then lineages. No alleles or families are shared by the two species, commonality being seen only at the lineage level. The overall nucleotide sequence diversity of MHC class I is estimated to be greater for modern chimpanzees than humans. Considering the numbers of lineages, families, and alleles, Patr-B and Patr-C have greater diversity than the HLA-B and HLA-C, respectively. In contrast, Patr-A has less polymorphism than HLA-A, due to the absence of A2 lineage alleles. The results are consistent with ancestral humans having passed through a narrower population bottleneck than chimpanzees, and with pathogen-mediated selection having favored either preservation of A2 lineage alleles on the human line and/or their extinction on the chimpanzee line.

Alleles↗

Normal V(D)J recombination in cells from patients with Nijmegen breakage syndrome.

The majority of antigen receptor diversity in mammals is generated by V(D)J recombination. During this process DNA double strand breaks are introduced at recombination signals by lymphoid specific RAG1/2 proteins generating blunt ended signal ends and hairpinned coding ends. Rejoining of all DNA ends requires ubiquitously expressed DNA repair proteins, such as Ku70/86 and DNA ligase IV/XRCC4. In addition, the formation of coding joints depends on the function of the scid gene encoding the catalytic subunit of DNA-dependent protein kinase, DNA-PK(CS), that is somehow required for processing of coding end hairpins. Recently, it was shown that purified RAG1/2 proteins can cleave DNA hairpins in vitro, but the same activity was also described for a protein complex of the DNA repair proteins Nbs1/Mre11/Rad50. This leaves the possibility that either protein complex might be involved in coding end processing in V(D)J recombination. We have therefore analyzed V(D)J recombination in cells from patients with Nijmegen breakage syndrome, carrying a mutation in the nbs1 gene. We find that V(D)J recombination frequencies and the quality of signal and coding joining are comparable to wild-type controls, as analyzed by a cellular V(D)J recombination assay. In addition, we did not detect significant differences in CDR3 sequences of endogenous Ig lambdaL and kappaL chain gene loci cloned from peripheral blood lymphocytes of an NBS patient and of healthy individuals. These findings suggest that the Nbs1/Mre11/Rad50 complex is not involved in coding end processing of V(D)J recombination.

Ataxia Telangiectasia↗

Is it Kawasaki disease?

Atypical cases of KD are common (up to 10% of the total) and the diagnosis should be considered without the full complement of diagnostic criteria. The risk of coronary dilation is high if IVIG is not given. Administration of IVIG is effective at preventing aneurysms, if given early. The high-risk groups for coronary artery disease are infants younger than 6 months of age and older children with very high platelet counts, high ESR and fever persisting for more than 2 weeks.

Child↗

Expression of the hydrogen peroxide-generating enzyme fatty acyl CoA oxidase activates NF-kappaB.

Peroxisome proliferators are a class of hepatic carcinogens in rodents and have been proposed to act in part by increasing oxidative stress. Fatty acyl CoA oxidase (FAO), which is highly induced by peroxisome proliferators, is the hydrogen peroxide-generating enzyme of the peroxisomal beta-oxidation pathway. We previously showed that the treatment of rats and mice with the peroxisome proliferator ciprofibrate resulted in increased hepatic NF-kappaB activity and suggested that this effect may be secondary to the action of H2O-generating enzymes. To test this possibility directly, we have determined whether transient overexpression of FAO, in the absence of peroxisome proliferators, leads to NF-kappaB activation. Here, we show that FAO overexpression in Cos-1 cells, in the presence of an H2O-generating substrate, can activate a NF-kappaB regulated reporter gene. Electrophoretic mobility shift assays further demonstrated that FAO expression increases nuclear NF-kappaB DNA binding activity in a dose-dependent manner. The antioxidants vitamin E and catalase can inhibit this activation. These results indicate that FAO mediates, at least in part, peroxisome proliferator-induced NF-kappaB activation.

Acyl-CoA Oxidase↗

The reliability of the Index of Orthodontic Treatment Need over time.

The aim of this investigation was to establish whether the Index of Orthodontic Treatment Need is reliable over time between the ages of 11 and 19 years. It consisted of a longitudinal sample of 314 11- and 15-year-old and 142 19-year-old subjects who had not received orthodontic treatment or extractions. The changes in the aesthetic component (AC) and the dental health component (DHC) of the Index of Orthodontic Treatment Need (IOTN) were measured between the ages of 11 and 19 years. The results suggested that the dental health component of IOTN was reliable over time between the ages of 11-19 years despite temporal changes in the separate occlusal traits that comprise the index. The aesthetic component of IOTN tended to show an improvement over time. The Index of Orthodontic Treatment Need is a reliable index over time when taking into account occlusal changes that are occurring during the 11-19-year age range. The study provides some reassurance to clinicians that an IOTN grading at age 11 years is unlikely to change by the time the patient is 19 years. Refereed Scientific Paper

Adolescent↗

Effects of a serotonin 5-HT(4) receptor antagonist SB-207266 on gastrointestinal motor and sensory function in humans.

BACKGROUND: Serotonin 5-HT(4) receptors are located on enteric cholinergic neurones and may regulate peristalsis. 5-HT(4) receptors on primary afferent neurones have been postulated to modulate visceral sensation. While 5-HT(4) agonists are used as prokinetic agents, the physiological role of 5-HT(4) receptors in the human gut is unknown. AIMS: Our aim was to characterise the role of 5-HT(4) receptors in regulating gastrointestinal motor and sensory function in healthy subjects under baseline and stimulated conditions with a 5-HT(4) receptor antagonist. METHODS: Part A compared the effects of placebo to four doses of a 5-HT(4) receptor antagonist (SB-207266) on the cisapride mediated increase in plasma aldosterone (a 5-HT(4) mediated response) and orocaecal transit in 18 subjects. In part B, 52 healthy subjects received placebo, or 0.05, 0.5, or 5 mg of SB-207266 for 10-12 days; gastric, small bowel, and colonic transit were measured by scintigraphy on days 7-9, and fasting and postprandial colonic motor function, compliance, and sensation during distensions were assessed on day 12. RESULTS: Part A: 0.5, 5, and 20 mg doses of SB-207266 had significant and quantitatively similar effects, antagonising the cisapride mediated increase in plasma aldosterone and acceleration of orocaecal transit. Part B: SB-207266 tended to delay colonic transit (geometric centre of isotope at 24 (p=0.06) and 48 hours (p=0.08)), but did not have dose related effects on transit, fasting or postprandial colonic motor activity, compliance, or sensation. CONCLUSION: 5-HT(4) receptors are involved in the regulation of cisapride stimulated orocaecal transit; SB 207266 tends to modulate colonic transit but not sensory functions or compliance in healthy human subjects.

Adolescent↗

Systemic effects of formoterol and salmeterol: a dose-response comparison in healthy subjects.

BACKGROUND: The main adverse effects of inhaled long acting beta(2) agonists relate to their systemic activity. The systemic effects seen over eight hours after inhalation of three doses of salmeterol and formoterol were therefore compared in normal subjects. METHODS: A double blind, randomised, crossover study was carried out in 16 healthy subjects who inhaled formoterol 24, 48 and 96 microg (via Turbuhaler((R))), salmeterol 100, 200 and 400 microg (via Diskhaler((R))), or placebo on separate days. Heart rate, systolic and diastolic blood pressure, and plasma potassium and glucose concentrations were measured for eight hours following each drug and mean values were used to plot the time course of change after each dose. Mean maximum (or minimum) absolute values were used to construct dose-response curves to calculate the relative dose potency of the two drugs. Lunch was taken after the four hour readings and, since this caused additional changes to the main outcome measures, data from the first four hours are also presented in a post hoc analysis. RESULTS: Both salmeterol and formoterol caused an early dose dependent increase in heart rate and glucose concentrations and a fall in diastolic blood pressure and plasma potassium concentration; formoterol also caused an early increase in systolic blood pressure. The cardiovascular effects occurred more rapidly than the metabolic effects and the response to formoterol was faster than that of salmeterol, apart from the glycaemic response. The effects of salmeterol were slightly more prolonged than those of formoterol, although some dose related effects were apparent at eight hours with both drugs. The relative dose potency for formoterol compared with salmeterol at four and eight hours for the different end points excluding systolic blood pressure ranged from 1.6 to 7.0 after adjusting for baseline values. Relative dose potencies (95% CI) for maximum heart rate and plasma potassium concentrations were 4.1 (3.0 to 5.6) and 5.8 (4.1 to 8.6) over four hours and 2.4 (1.2 to 3.8) and 3.0 (1.2 to 5.7) over eight hours. CONCLUSIONS: Formoterol and salmeterol cause dose related changes in heart rate, diastolic blood pressure, and plasma glucose and potassium concentrations. Formoterol has a more rapid onset for most end points whereas salmeterol has slightly more prolonged activity. Both drugs have a relatively modest therapeutic window. The relative dose potencies of the two drugs for the main end points were similar to the fourfold difference in recommended doses. Some differences in the pharmacological profile of the two drugs emerged and are as yet unexplained.

Adolescent↗