Morning compared to afternoon school-based exercise on cognitive function in adolescents.

PURPOSE: Adolescents may be less ready to learn in the mornings due to a propensity for waking up later. High-intensity interval exercise (HIIE) has been shown to acutely improve cognitive functioning in teenagers. This within-measures study explored whether the benefit of HIIE differs when delivered in the morning or afternoon. METHODS: 37 teenagers (19 boys, 13.7 ± 0.4 years) each completed 3 trials in school; morning HIIE (MORN), afternoon HIIE (AFTER) and a no-exercise control trial (CON). The HIIE involved 10x10 second sprints, interspersed by 50 s of walking. Cognitive function was assessed using a battery of computerised tasks four times over the course of the day. RESULTS: Z scores for reaction time, but not proportion of correct responses, were improved 45 min post exercise in the MORN trial (P < 0.01, d = 0.47), and this improvement persisted until the third (P = 0.04, d = 0.34), but not final (P = 0.93, d = 0.01), time point. Global reaction time was not improved 45 min post exercise in the AFTER trial (P = 0.17, d = 0.20). Global reaction time was quicker 45 min post morning exercise compared to the same time point in CON (P = 0.02, d = 0.56) and AFTER (P = 0.01, d = 0.72). CONCLUSION: HIIE may be more effectual in improving cognitive functioning when delivered in the morning.

The acute influence of amateur boxing on dynamic cerebral autoregulation and cerebrovascular reactivity to carbon dioxide.

PURPOSE: The purpose of this study was to investigate the acute effect of head impacts, sustained over the course of three rounds of amateur boxing, on indices of cerebrovascular function. METHODS: Eighteen university amateur boxers (six female) completed three experimental trials in a randomised order; (1) three rounds of boxing (BOX), (2) an equivalent bout of pad boxing (where no blows to the head were sustained; PAD), and (3) a time-matched seated control trial (CON). Indices of cerebrovascular function were determined immediately before and 45 min after each trial. Specifically, dynamic cerebral autoregulation (dCA) was determined by considering the relationship between changes in cerebral blood velocity and mean arterial pressure during 5 min of squat-stand manoeuvres at 0.05 and 0.10 Hz. Cerebrovascular reactivity was determined using serial breath holding and hyperventilation attempts. RESULTS: Participants received an average of 40 ± 16 punches to the head during the BOX trial. Diastolic, mean and systolic dCA phase during squat stand manoeuvres at 0.05 Hz was lower after BOX compared to pre BOX (P ≤ 0.02, effect size (d) ≥ 0.74). No other alterations in dCA outcomes were observed at 0.05 or 0.10 Hz. The number of head impacts received during the BOX trial was associated with the change in systolic phase (r = 0.50, P = 0.03). No differences in cerebrovascular reactivity to breath holding or hyperventilation were observed. CONCLUSIONS: A typical bout of amateur boxing (i.e., three rounds) can subtly alter cerebral pressure-flow dynamics, and the magnitude of this change may be related to head impact exposure.

The acute influence of sucrose consumption with and without vitamin C co-ingestion on microvascular reactivity in healthy young adults.

BACKGROUND: Sugar sweetened beverages (SSB) are a major source of dietary sugar and a public health concern. Glucose consumption acutely influences microvascular reactivity in healthy adults, possibly via oxidative stress. The purpose of this study was to observe the acute influence of a more relevant dose of sucrose on microvascular reactivity, and to identify whether this response is influenced by the amount of vitamin C typically contained in SSB. METHODS: Thirteen ostensibly healthy adults (8 male, 5 female) performed three 1-day trials in a randomized order; the consumption of 300 ml water (control; CON), or 300 ml water with 50 g sucrose (SUGAR) or 50 g sucrose with 160 mg of vitamin C (VITC). Near infrared spectroscopy was used to determine peak reactive hyperaemia (PRH), the rate of desaturation (Slope 1) and reperfusion (Slope 2), and the total area under the reperfusion curve versus time (TRH) following 5 min of forearm cuff occlusion before and 30, 60, 90 and 120 min after test drink consumption. RESULTS: SUGAR and VITC significantly increased the total area under the curve versus time for plasma glucose (P < 0.05 for both). No changes in microvascular reactivity were observed between trials, although VITC increased Slope 1 compared to both SUGAR and CON 30 and 60 min post drink (P < 0.05 for both). CONCLUSION: The consumption of a sugar load representative of commercially available SSB did not influence microvascular reactivity. The co-ingestion of Vitamin C also failed to influence microvascular reactivity, but did increase the rate of oxygen extraction.

Exercise intensity and the protection from postprandial vascular dysfunction in adolescents.

Acute exercise transiently improves endothelial function and protects the vasculature from the deleterious effects of a high-fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 yr) completed three 1-day trials: 1) rest (CON); 2) 8 × 1 min cycling at 90% peak power with 75 s recovery [high-intensity interval exercise (HIIE)]; and 3) cycling at 90% of the gas exchange threshold [moderate-intensity exercise (MIE)] 1 h before consuming a HFM (1.50 g/kg fat). Macrovascular and microvascular endothelial function was assessed before and immediately after exercise and 3 h after the HFM by flow-mediated dilation (FMD) and laser Doppler imaging [peak reactive hyperemia (PRH)]. FMD and PRH increased 1 h after HIIE [P < 0.001, effect size (ES) = 1.20 and P = 0.048, ES = 0.56] but were unchanged after MIE. FMD and PRH were attenuated 3 h after the HFM in CON (P < 0.001, ES = 1.78 and P = 0.02, ES = 0.59). FMD remained greater 3 h after the HFM in HIIE compared with MIE (P < 0.001, ES = 1.47) and CON (P < 0.001, ES = 2.54), and in MIE compared with CON (P < 0.001, ES = 1.40). Compared with CON, PRH was greater 3 h after the HFM in HIIE (P = 0.02, ES = 0.71) and MIE (P = 0.02, ES = 0.84), with no differences between HIIE and MIE (P = 0.72, ES = 0.16). Plasma triacylglycerol concentration and total antioxidant status concentration were not different between trials. We conclude that exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups.

Perceptions of quality of life and priorities of owners of cats with heart disease.

BACKGROUND: Owners' perceptions and priorities regarding quality of life (QoL) are important considerations given the unknown efficacy of many commonly administered medications, stress of hospital visits, difficulties providing home care, and personal choices including euthanasia. OBJECTIVE: To describe the relative importance of quality versus quantity of life to owners of cats with heart disease. ANIMALS: Two hundred and thirty-nine cats with heart disease. METHODS: Prospective questionnaire-based clinical study. Cat owners completed a questionnaire to identify important parameters when assessing their cat's QoL, the relative importance of quality versus quantity of life, and willingness to trade survival time for QoL. Variables associated with these parameters were evaluated with multivariate analyses. RESULTS: Appetite, owner interaction, sleep patterns, and litterbox habits were deemed important to QoL. Concern over pet suffering was significantly greater than concern over life expectancy. Ninety-three percent of owners were willing to trade survival time for good QoL; 57% of these were willing to trade up to 6 months. On multivariate analysis, the only factor significantly (P=.002) associated with willingness to trade 6 months was study site. Owner concern regarding stress of administering medications at home increased with number and frequency of medications. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicated that QoL is more important to owners of cats with heart disease than longevity. The various priorities and concerns of cat owners should be taken into account in order to provide optimal care.

The immunoglobulin octanucleotide: independent activity and selective interaction with enhancers.

The thymidine kinase (tk) promoter of herpes simplex virus includes an octanucleotide sequence motif (ATTTGCAT) that is also an essential component of immunoglobulin kappa gene promoters. In the absence of an enhancer, tk promoter derivatives that contain this element support a higher rate of transcription than those that lack it. The action of the kappa enhancer augments that of the octanucleotide in B lymphoid cells; when both elements are present, tk promoter activity is increased by more than an order of magnitude. In contrast, the presence of the octanucleotide in this promoter markedly reduces its response to a nonimmunoglobulin enhancer. These results suggest that the octanucleotide may mediate a selective interaction among promoters and enhancers.

Survey of trainers on the use of swimming exercise for Standardbred racehorses in Australia.

OBJECTIVES: To determine swimming training practices in Australian harness racing horses and potential targets for future research. METHODS: An online survey of Australian Standardbred trainers and telephone interviews with 20 leading trainers were conducted. Questions relating to swimming facility and protocol, perceived benefits and contraindications were included. Descriptive data analysis was performed. RESULTS: Data were collected from 270 trainers: 250 by online survey (250/1770, response rate 14.1%) and 20 by interview. Of these, 103 trainers (38.1%), including 91 surveyed trainers (91/250, 36.4%) and 12 interviewed trainers (12/20, 60.0%), used swimming exercise. The most popular reasons for swimming were to replace trackwork for horses with limb injuries (79.4%), improve or maintain fitness (62.7%) and provide mental stimulation through variety in training (40.0%). Free swimming (78.4%) was more common than tethered, but the frequency and duration for horses in full training varied widely between trainers, with a median of four swim sessions per horse each week (range 0.5-12) for a median of 7 min (range 1.5-30 min) per session, mostly as a continuous swim, but sometimes as intervals. The main reasons given by those not swimming horses were lack of an adequate facility (60.5%) and lack of perceived benefit (16.2%). Reasons for not swimming individual horses varied widely. CONCLUSIONS: Trainer opinions and protocols varied widely with respect to swimming exercise for Standardbred race horses. The role of swimming exercise requires further study so that evidence-based recommendations can be made.

Differential expression of IEG mRNA in rat brain following acute treatment with clozapine or haloperidol: a semi-quantitative RT-PCR study.

Antipsychotic drugs have been shown to modulate immediate early gene (IEG) expression in rat brain regions that are associated with schizophrenia, which may be directly linked to their immediate therapeutic benefit. In this study, we analysed the expression profile of a series of IEGs (c-fos, c-jun, fra-1, Krox-20, Krox-24, arc, sgk-1, BDNF and NARP) in six rat brain regions (prefrontal cortex, hippocampus, striatum, nucleus accumbens, thalamus and cerebellum). Rats (n=5) were administered either clozapine (20 mg/kg i.p.), haloperidol (1 mg/kg i.p.) or the appropriate vehicle with pre-treatment times of 1, 6 and 24 h. IEG expression was analysed in these regions by Taqman RT-PCR. The spatial and temporal profile of IEG induction following antipsychotic drug treatment correlates with regions associated with the efficacy and side effect profile of each drug. In particular, sgk-1 expression levels after antipsychotic drug treatment may have predictive value when investigating the profile of a novel antipsychotic drug.

The Drosophila melanogaster actin 5C gene uses two transcription initiation sites and three polyadenylation sites to express multiple mRNA species.

At least six mRNAs are made from the Drosophila melanogaster act5C gene. We investigated the structures of these RNAs in detail and determined that they are heterogeneous at both their 5' and 3' ends. At the 5' end there were two nonhomologous leader exons which were alternately spliced to the remainder of the gene. These leader exons mapped to 1.7 and 0.7 kilobases, respectively, upstream of a common splice acceptor site which was eight base pairs 5' to the translation initiator AUG. Exon 1 is 147 bases in length, while exon 2 is 111 bases. A consensus TATA sequence was found roughly 30 base pairs upstream from exon 1, but none was found in the analogous position upstream of exon 2. The transcript length diversity arose principally from the use of three polyadenylation sites. This gave rise to RNA molecules with 3'-untranslated regions of roughly 375, 655, and 945 base pairs. With two start sites and three termination sites, this gene has the potential to produce six different transcripts. All six possible transcripts were present in whole fly mRNA. Transcripts containing the two different leader exons were found in roughly the same relative quantities through development. In contrast, the various 3' ends were differentially represented through development.

Functional dissection of the human Bcl2 protein: sequence requirements for inhibition of apoptosis.

Overexpression of the cytoplasmic oncoprotein Bcl2 blocks programmed cell death (apoptosis) in many cellular systems. To map the sequences in Bcl2 that are necessary for its activity, we created a library of deletion-scanning mutants of this 239-amino-acid protein and tested their abilities to block staurosporine-induced fibroblast apoptosis, using a novel transient-transfection assay. Phenotypes of informative mutants were then confirmed by assaying for inhibition of steroid-induced apoptosis in stably transfected T-lymphoid cells. In accordance with earlier results, we found that Bcl2 activity was only partially reduced after deletion of the hydrophobic tail that normally anchors it in cytoplasmic membranes. Essential sequences were found in the remainder of the protein and appeared to be organized in at least two discrete functional domains. The larger, more C-terminal region (within residues 90 to 203) encompassed, but extended beyond, two oligopeptide motifs called BH1 and BH2, which are known to mediate dimerization of Bcl2 and related proteins. The second, more N-terminal regions (within residues 6 to 31) was not required for protein dimerization in vivo, but its deletion imparted a dominant negative phenotype, yielding mutants that promoted rather than inhibited apoptotic death. Residues 30 to 91 were not absolutely required for function; by deleting most of this region along with the hydrophobic tail, we derived a 155-residue mini-Bcl2 that retains significant ability to inhibit apoptosis.

Age-related changes in photosynthesis of woody plants.

Woody peoffnials do not appear to go through a defined senescence phase but do have predictable developmental stages. Reduced photosynthesis and stomatal conductance have been reported at all developmental transitions, although some studies have shown the opposite. What causes these changes and why do results differ among studies? Do these changes result from or cause changes in growth? What are the roles of genetics, size, changing conditions and cumulative environmental stress in aging trees? Definitive answers remain elusive but recent research is helping to clarify some of the processes associated with aging and to point the way for further study.

A matrix metalloproteinase induction/activation system exists in the human left ventricular myocardium and is upregulated in heart failure.

BACKGROUND: Matrix metalloproteinases (MMPs) contribute to matrix remodeling in disease states such as tumor metastases. Extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to increase MMP expression, and membrane-type MMP or MT1-MMP has been implicated to activate MMPs. The present study examined whether and to what degree EMMPRIN and MT1-MMP were expressed in human left ventricular (LV) myocardium as well as the association with MMP activity and expression in dilated cardiomyopathy (DCM). METHODS AND RESULTS: LV myocardial zymographic MMP activity increased by >2-fold with both nonischemic DCM (n=21) and ischemic DCM (n=16) compared with normal (n=13). LV myocardial abundance of MMP-9 was increased with both forms of DCM. MMP-2 and MMP-3 were increased with nonischemic DCM. MMP-1 levels were decreased with both forms of DCM. EMMPRIN increased by >250% and MT1-MMP increased by >1000% with both forms of DCM. CONCLUSIONS: Increased LV myocardial MMP activity and selective upregulation of MMPs with nonischemic and ischemic forms of DCM occurred. Moreover, a local MMP induction/activation system was identified in isolated normal human LV myocytes that was upregulated with DCM. The control of MMP activation and expression in the failing human LV myocardium represents a new and potentially significant therapeutic target for this disease process.

Peroxisome proliferator-activated receptor-gamma agonist, rosiglitazone, protects against nephropathy and pancreatic islet abnormalities in Zucker fatty rats.

Rosiglitazone (BRL 49653), a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist and potent insulin action-enhancing agent, was given in the diet (50 micromol/kg of diet) to male Zucker rats ages 6-7 weeks for 9 months (prevention group). In this treatment mode, rosiglitazone prolonged the time to onset of proteinuria from 3 to 6 months and markedly reduced the rate of its subsequent progression. Progression was also retarded when treatment was commenced (intervention group) after proteinuria had become established (4 months; ages 24-25 weeks). In either treatment mode, rosiglitazone normalized urinary N-acetyl-beta-D-glucosaminidase activity, a marker for renal proximal tubular damage, and ameliorated the rise in systolic blood pressure that occurred coincidentally with the development of proteinuria in Zucker fatty control rats. The renal protective action of rosiglitazone was verified morphologically. Thus in the prevention group there was an absence of the various indexes of chronic nephropathy that were prominent in the Zucker fatty control group, namely, glomerulosclerosis, dilated tubules containing proteinaceous casts, a loss of functional microvilli on the tubular epithelium, and varying degrees of chronic interstitial nephritis. An intermediate pathology was observed in the intervention group. Also, pancreatic islet hyperplasia, ultrastructural evidence of beta-cell work hypertrophy, and derangement of alpha-cell distribution within the islet were prominent features of Zucker fatty control rats, but these adaptive changes were ameliorated (intervention group) or prevented (prevention group) by rosiglitazone treatment. These data demonstrate that treatment of Zucker fatty rats with rosiglitazone produced substantial protection over a prolonged period against the development and progression of renal injury and the adaptive changes to pancreatic islet morphology caused by sustained hyperinsulinemia.

Myocardial matrix degradation and metalloproteinase activation in the failing heart: a potential therapeutic target.

A fundamental structural event in the progression of heart failure due to dilated cardiomyopathy is left ventricular (LV) myocardial remodeling. The matrix metalloproteinases (MMPs) are an endogenous family of enzymes which contribute to matrix remodeling in several disease states. The goal of this report is to summarize recent findings regarding the myocardial MMP system and the relation to matrix remodeling in the failing heart. In both experimental and clinical forms of dilated cardiomyopathy (DCM), increased expression of certain species of myocardial MMPs have been demonstrated. Specifically, increased myocardial levels of the gelatinase, MMP-9 has been identified in both ischemic and non-ischemic forms of human DCM. In addition, stromelysin or MMP-3 increased by over four-fold in DCM. The increased levels of MMP-3 in DCM may have particular importance since this MMP degrades a wide range of extracellular proteins and can activate other MMPs. In normal human LV myocardium, the membrane type 1 MMP (MT1-MMP) was detected. These MT-MMPs may provide important sites for local MMP activation within the myocardium. In a pacing model of LV failure, MMP expression and activity increased early and were temporally associated with LV myocardial matrix remodeling. Using a broad-spectrum pharmacological MMP inhibitor in this pacing model, the degree of LV dilation was attenuated and associated with an improvement in LV pump function. Thus, increased LV myocardial MMP expression and activity are contributory factors in the LV remodeling process in cardiomyopathic disease states. Regulation of myocardial MMP expression and activity may be an important therapeutic target for controlling myocardial matrix remodeling in the setting of developing heart failure.

Granulomatous slack skin: clonal rearrangement of the T-cell receptor beta gene is evidence for the lymphoproliferative nature of a cutaneous elastolytic disorder.

Granulomatous slack skin (GSS) is characterized by the slow evolution of bulky, erythematous skin folds that have a granulomatous histology, and show destruction of dermal elastic tissue. Several cases have been putatively associated with Hodgkin's disease, and histologic similarities to mycosis fungoides have also been noted. We examined tissue from 3 cases of GSS to determine whether the condition was inflammatory or lymphoproliferative in nature. We found an abnormal, monomorphous T-helper cell immunophenotype, and in all 3 cases, clonal rearrangement of the T-cell receptor beta gene. We conclude that GSS is an indolent cutaneous T-cell lymphoma associated with granulomatous inflammation that mediates elastolysis, producing a distinctive clinical appearance.

Neurointermediate pituitary lobe cells synthesize and release interleukin-6 in vitro: effects of lipopolysaccharide and interleukin-1 beta.

The cytokine interleukin-6 (IL-6) is produced by a variety of cells, including macrophages, T-cells, and B-cells. Recent studies have confirmed a neuroendocrine role for IL-6 in the regulation of anterior pituitary (AP) hormone release. Because the neurointermediate pituitary lobe (NIL) may modulate AP hormone release, we investigated the production of IL-6 by NIL cells in vitro. NIL tissue removed from pituitary glands of male Long-Evans rats was enzymatically and mechanically dispersed, and the cells were subsequently cultured in 96-well tissue culture plates for 4-6 days in 10% serum-containing RPMI-1640. Test incubations were performed in serum-free RPMI-1640, and IL-6 concentrations were determined using the 7TD1 cell bioassay. Preliminary studies revealed a cell-dependent release of IL-6: increasing the number of NIL cells per well from 6.25 to 50 x 10(3) revealed detectable basal release of IL-6 between 25-50 x 10(3) cells/well. The endotoxin lipopolysaccharide (LPS; 100 ng/ml) and IL-1 beta (100 ng/ml) stimulated IL-6 release at 25 and 50 x 10(3) cells/well. Subsequent studies used a cell density of 50 x 10(3) cells/well and demonstrated time-dependent 3- to 6-fold inductions of IL-6 release by 100 ng/ml IL-1 beta and LPS. Concentration-response studies revealed maximal stimulation of IL-6 release by 1 ng/ml and a minimally effective concentration of 1 pg/ml for both IL-1 beta and LPS. Treatment of NIL cells with 1-10 mM (Bu)2cAMP increased IL-6 release by 7- to 14-fold. Endotoxin and IL-1 beta also enhanced the accumulation of IL-6 messenger RNA in these cells. Vasopressin and oxytocin (1 microM) inhibited LPS and IL-1 beta stimulation of IL-6 release from NIL cells, but did not inhibit IL-6 release from AP cells. Immunofluorescent dual labeling of NIL cells for flow cytometry revealed that greater than 95% of the cells did not stain for CD11b/c (common epitope found on monocytes, granulocytes, and macrophages) or CD45 (leukocyte common antigen). These results demonstrate for the first time the synthesis and release of IL-6 from cultured NIL cells. Agents that enhance IL-6 release [LPS, IL-1 beta, and (Bu)2cAMP] from other cell types also increase IL-6 release from NIL cells. Vasopressin and oxytocin inhibition of IL-6 release suggests a role for these neuropeptides in feedback inhibition in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

Cholesterol lowering and bile acid excretion in the hamster with cholestyramine treatment.

Cholestyramine was administered to hamsters at 6 doses in the diet for 1 week. Plasma cholesterol, LDL + VLDL cholesterol and HDL cholesterol were measured after this period. Bile acid excretion was measured in faeces collected over the final 24 h of the experiment. A dose-response curve for each parameter measured was constructed using data from individual hamsters. For the bile acid and the cholesterol measurements a maximum response was observed at the highest doses. A correlation between the bile acids excreted over 24 h and the LDL + VLDL cholesterol showed that the maximum effect of cholestyramine on lowering plasma and lipoprotein cholesterol occurred at a submaximal excretion level of bile acids. Comparison of the efficiency of cholestyramine in reducing plasma cholesterol in the hamster with limited data in the dog and in man suggest that a greater lowering of plasma cholesterol is achieved in the dog and in man for an equivalent increase in bile acid excretion caused by the sequestrant. As is already known, cholestyramine treatment caused an increase in hepatic cholesterol 7 alpha-hydroxylase and HMG-CoA reductase activity. Interestingly in this study the novel observation was made that the bile acid sequestrant reduced the activity of hepatic acyl-CoA: cholesterol acyltransferase.

SK&F 97426-A a more potent bile acid sequestrant and hypocholesterolaemic agent than cholestyramine in the hamster.

SK&F 97426-A is a novel bile acid sequestrant which was selected for comparison with cholestyramine in vivo because of its superior in vitro bile acid binding properties. The effects of the two sequestrants on faecal bile acid excretion, plasma total cholesterol, VLDL + LDL and HDL cholesterol and triglyceride concentrations and on liver enzymes involved in the synthesis and metabolism of cholesterol were investigated in normocholesterolaemic hamsters. Four studies were conducted to determine the relative potencies of the two resins using a range of doses of the sequestrants over treatment periods of up to 2 weeks. Curves fitted to the resulting data allowed common maximum responses and separate ED50s to be calculated for each sequestrant. The maximum response of both sequestrants was to increase bile acid excretion by 352% and lower plasma total cholesterol by 37-58%. LDL + VLDL and HDL cholesterol were reduced by 56-75% and 25-41%, respectively. SK&F 97426-A was 3 times more potent than cholestyramine at increasing the excretion of bile acids in the faeces and 2.1-3.4-fold and 2.3-3.2-fold more potent at lowering total plasma cholesterol and LDL plus VLDL cholesterol, respectively. In some of the experiments SK&F 97426-A was also more potent than cholestyramine at lowering HDL cholesterol. Plasma triglycerides were also lowered by both sequestrants by up to 31% after 1 week but the relative potency could not be determined. These HDL cholesterol and total triglyceride lowering effects of bile acid sequestrants in the hamster are known not to occur in people treated with cholestyramine. There were minimal differences between hamsters treated for 1 or 2 weeks in the relative potencies or ED50s calculated for the total plasma cholesterol, LDL + VLDL and HDL cholesterol. Both sequestrants may have been slightly more efficacious on these parameters after 2 weeks of treatment. Liver weights were reduced by about 15% by both sequestrants at 2% (w/w) in the diet for 1 week. The activities of the liver HMG-CoA reductase and cholesterol 7 alpha-hydroxylase were increased as expected, whilst the activity of the acyl-CoA:cholesterol acyltransferase was reduced by both sequestrants at this dose. SK&F 97426-A was, therefore, 2-3-fold more potent as a bile acid sequestrant and hypocholesterolaemic agent than cholestyramine when tested in the hamster.

Determination of changes in mRNA expression in a rat model of neuropathic pain by Taqman quantitative RT-PCR.

The aim of this study was to develop a rapid and accurate high throughput method of screening multiple genes across a single sample set to detect changes in gene expression in the dorsal root ganglion (DRG) following partial sciatic nerve ligation in the rat. Using Taqman quantitative RT-PCR, we show that expression of a number of genes, including galanin, vasointestinal peptide and neuropeptide Y are rapidly increased 24 h post-operation in the DRGs on the ligated side only. Other genes tested, including vanilloid receptor-1, substance P, galanin receptor-2 and housekeeping genes did not alter. Analysis of the expression of ASIC4 showed a small difference in expression at 7 days post ligation. By applying a statistical method for analysis of multiple variables, partial least squares, we show that the expression change of ASIC4 was significantly altered on the ligated side even though the change was small. This method will allow us to rapidly identify changes in expression of candidate genes that may be involved in adaptive responses in the DRG due to nerve injury.

Caspase mRNA expression in a rat model of focal cerebral ischemia.

Proteins of the caspase family are involved in the signalling pathway that ultimately leads to programmed cell death (apoptosis), which has been reported to occur in some experimental models of stroke. In a previous paper we used quantitative reverse transcription and polymerase chain reaction (RT-PCR) to characterise changes in the mRNA expression of one member of this family, caspase-3, in a rat model of permanent focal ischemia. Here we have used this technique to study the expression of a further three caspases which are involved in different aspects of caspase signalling. Caspase-8, involved in Fas-mediated apoptosis, was upregulated in the cortex of ischemic rats. Caspase-11, which leads to the synthesis of the functional form of the cytokine interleukin-1 beta, also showed increased expression, but with a different temporal profile from caspase-8. In contrast, caspase-9, which forms part of the pathway signalling through the mitochondria, showed a decrease in expression. The expression of a further four caspases (1, 2, 6 and 7) has also been characterised in a simpler experiment. These caspases all showed distinctive patterns of expression following the induction of ischemia. These data lead us to conclude that caspase expression as a whole is under very strict transcriptional control in this model. Certain elements of caspase signalling, such as the Fas-induced pathway and the events upstream of IL-1 beta processing, are upregulated, while others are not. This may be due to some form of genetic program activated in response to ischemia in the brain and may highlight which biological pathways are modulated.