Saving bones without risking brain-bisphosphonates and risk of stroke: matched case-control study.

We investigated the association between bisphosphonate treatment and the risk of stroke using a large routine clinical dataset. We found no association between bisphosphonate treatment and risk of stroke, after adjusting for large number of clinical and demographic confounders. INTRODUCTION: There is conflicting evidence on the link between bisphosphonates and stroke with studies variously showing increased, decreased or unchanged risk. We investigated the association between bisphosphonate treatment and the risk of stroke using a large routine clinical dataset. METHODS: We used a matched nested case-control study design analysing routinely collected electronic data from patients registered at primary care practices in England participating in the Royal College of General Practitioners Research and Surveillance Centre. Cases were patients aged 18 years or over, either living or dead, recorded as having had a stroke in the period 1 January 2005 to 31 March 2016. Each case was matched to one control according to age, sex, general practice attended and calendar time. Data were analysed using Stata, version 14.2. and RStudio, version 1.1.463. Conditional logistic regression was used to determine odds ratios for stroke according to bisphosphonate treatment and duration in cases compared with controls. We adjusted for disease risk groups, cardiovascular risk factors, treatments, smoking status, alcohol consumption, ethnicity, bisphosphonate types, fracture and socioeconomic status using IMD (Index of Multiple Deprivation). RESULTS: We included 31,414 cases of stroke with an equal number of matched controls. Overall, 83.2% of cases and controls were aged 65 years or older, and there were similar proportions of females (51.5%) and males (48.5%). Bisphosphonate treatment was not associated with stroke after adjusting for the wide range of confounders considered (OR 0.86, 95% CI 0.62-1.19). CONCLUSIONS: We found no association between bisphosphonate treatment and risk of stroke, after adjusting for other confounders.

Supervised pharmacy student-led medication review in primary care for patients with type 2 diabetes: a randomised controlled pilot study.

OBJECTIVE: To pilot and feasibility-test supervised final year undergraduate pharmacy student-led medication reviews for patients with diabetes to enable definitive trial design. METHOD: Third year pharmacy students were recruited from one UK School of Pharmacy and trained to review patient's medical records and provide face-to-face consultations under supervision while situated within the patient's medical practice. Patients with type 2 diabetes were recruited by postal invitation letter from their medical practice and randomised via automated system to intervention or usual care. Diabetes-related clinical data, quality of life, patient reported beliefs, adherence and satisfaction with medicines information were collected with validated tools at baseline and 6 months postintervention. The process for collecting resource utilisation data was tested. Stakeholder meetings were held before and after intervention to develop study design and learn from its implementation. Recruitment and attrition rates were determined plus the quality of the outcome data. Power calculations for a definitive trial were performed on the different outcome measures to identify the most appropriate primary outcome measure. RESULTS: 792 patients were identified as eligible from five medical practices. 133 (16.8%) were recruited and randomised to control (n=66) or usual care (n=67). 32 students provided the complete intervention to 58 patients. Initial data analysis showed potential for impact in the right direction for some outcomes measured including glycated haemoglobin, quality of life and patient satisfaction with information about medicines. The intervention was found to be feasible and acceptable to patients. The pilot and feasibility study enabled the design of a future full randomised controlled trial. CONCLUSIONS: Student and patient recruitment are possible. The intervention was well received and demonstrated some potential benefits. While the intervention was relatively inexpensive and provided an experiential learning opportunity for pharmacy students, its cost-effectiveness remains to be determined. TRIAL REGISTRATION NUMBER: ISRCTN26445805; Results.

Drug combinations in syringe drivers: the compatibility and stability of diamorphine with cyclizine and haloperidol.

The compatibility and stability of 2B combinations of diamorphine hydrochloride (5-100 mg/ml) with cyclizine lactate (5-50 mg/ml), eight combinations of diamorphine (10-100 mg/ml) with haloperidol (2-4 mg/ml) and eight combinations of all three drugs was assessed after storage in 1 ml polypropylene syringes. Samples were stored for periods up to seven days in the light and at room temperature (22 degrees C). Five combinations of diamorphine with cyclizine precipitated immediately upon preparation. After analysis and determination of t90% values (the time taken for 10% degradation). 16 of the remaining 23 combinations were judged to be compatible (no signs of crystallization or precipitation) and stable (less than 10% loss of potency of either drug) after storage for 24 h. After seven days storage only four remained compatible and stable. The results indicate that ratios of diamorphine to cyclizine of 1:1 are stable at concentrations up to 20 mg/ml. An increase in diamorphine concentration necessitates a reduction in cyclizine to 10 mg/ml, and an increase in cyclizine concentration necessitates a reduction in concentration of diamorphine to 15 mg/ml to maintain stability over 24 h. All the combinations of diamorphine with haloperidol remained compatible and stable for seven days. The addition of haloperidol (2 mg/ml) to the diamorphine and cyclizine combinations had no detrimental effect on their compatibility and stability. A stability curve is included as an easy way for palliative care personnel to avoid potential problems with incompatibilities and reduced stability when using these combinations. Furthermore, to reduce the possibility of precipitation with mixtures containing cyclizine, the use of 0.9% sodium chloride should be avoided.

A comparison of the endotoxin-retentive abilities of two '96-h' in-line intravenous filters.

The ability of two in-line intravenous filters, the Pall Intravenous Set Saver Filter ELD96 and the Codan I.V. S SET-P, to retain endotoxin released by Pseudomonas aeruginosa during filtration of amino-acid-based parenteral nutrition (PN) solutions was investigated. When challenged with 10(8) cells of P. aeruginosa during simulated clinical PN infusion, the Pall ELD96 was shown to be capable of providing an effluent free of detectable endotoxin (< 0.3125 EUE/ml). In contrast, the Codan I.V. S SET-P allowed significant amounts of endotoxin to pass through.

Hypertriglyceridemia in experimental diabetes: relationship to cardiac dysfunction.

The incidence of mortality from cardiovascular disease is higher in diabetic patients. The objective of the present investigation was to test the hypothesis that the diabetes-induced depression in cardiac function may be due to hypertriglyceridemia. Hyperlipidemia and a depressed left ventricular developed pressure and rate of increase and decrease of ventricular pressure (+/- dP/dt) were produced in isolated hearts from rats made diabetic with streptozotocin compared with hearts from control animals. This depressed cardiac performance was successfully prevented by hydralazine treatment (for 3 weeks), which also lowered plasma triglyceride levels and suggested that hyperlipidemia may be important in altering cardiac function in experimental diabetic rats. The beneficial effects of clofibrate, verapamil, prazosin, enalapril, and benazepril administration were then studied in diabetic rats. The treatments (with the exception of enalapril) significantly reduced plasma triglyceride levels but did not prevent the onset of heart dysfunction in chronically diabetic rats. These studies suggest that in the chronically diabetic rat, hypertriglyceridemia may not be as important as previously suggested, in the development of cardiac dysfunction. Since acute dichloroacetate perfusion improves cardiac function in 6 week (but not 24 week) diabetic rats, it appears more likely that improving myocardial glycose utilization is more critical than triglyceride lowering, in preventing cardiac dysfunction in the diabetic rat at this time point.

Sensitivity changes to inotropic agents in rabbit atria after chronic experimental diabetes.

The effect of experimental diabetes on the sensitivity of isolated left atrial strips to inotropic agents was investigated in rabbits made diabetic with alloxan. After 4 weeks of diabetes no change in sensitivity was detected in response to isoproterenol or ouabain. In contrast, 15 weeks of diabetes induced a decreased sensitivity to beta-adrenergic stimulation, exhibited as a shift to the right in concentration-response curves obtained in response to isoproterenol and noradrenaline. In addition, after 15 weeks of diabetes the inotropic response to ouabain was depressed, and a small decrease in sensitivity was detected in response to forskolin. In contrast, no significant changes in the concentration-response curves obtained from alpha-adrenergic stimulation by phenylephrine or calcium chloride were detected. Unlike the streptozotocin diabetic rat, which exhibits low serum thyroid hormone levels, no changes in serum thyroid hormones were detected in the alloxan diabetic rabbit. It is suggested that the increased inotropic sensitivity to alpha-adrenergic agonists observed in the diabetic rat, but not in the rabbit, may be due to low serum thyroid hormone levels. In contrast, the deleterious effects of diabetes on beta-adrenergic and ouabain sensitivity occur independently of changes in serum thyroid hormones.

Hyperthyroidism induces supersensitivity to biogenic amines in rat vascular tissue via a pre- and a postjunctional mechanism.

The effect of hyperthyroidism was investigated on the sensitivity of rat aortic and mesenteric arteries to the contractile effects of biogenic amines, K+ and Ca++. Supersensitivity to norepinephrine, methoxamine and clonidine was observed in the mesenteric artery. Methoxamine and clonidine are immune to disposition by neuronal and extraneuronal uptake, and supersensitivity to norepinephrine persisted in the presence of hydrocortisone and desmethylimipramine, suggesting that the supersensitivity was postjunctional in origin. In addition, reserpine pretreatment induced supersensitivity to norepinephrine in control mesenteric arteries, but in hyperthyroid mesenteric arteries no further increase in sensitivity was observed after reserpine pretreatment supporting a postjunctional mechanism. In the aorta, a small increase in sensitivity was observed to norepinephrine, no supersensitivity was detected to methoxamine and supersensitivity to norepinephrine was not apparent in the presence of hydrocortisone, suggesting a prejunctional mechanism. The existence of a small prejunctional component in the mesenteric artery also was indicated, as incubation with hydrocortisone attenuated the degree of supersensitivity after thyroid hormone pretreatment. In the mesenteric artery, postjunctional supersensitivity also was observed to 5-hydroxytryptamine. However, no increase in sensitivity was observed to KCl or CaCl2 suggesting that the postjunctional supersensitivity was not due to an increase in the sensitivity of the contractile apparatus, and was specific for receptor-mediated effects of agonists.

Cardiac alpha- and beta-adrenoceptor sensitivity and binding characteristics after chronic reserpine pretreatment.

Cardiac alpha- and beta-adrenoceptor sensitivities were examined after chronic pretreatment of rats with reserpine. Increases in sensitivity would indicate that the receptor is under the influence of the sympathetic innervation, removal by catecholamine depletion with reserpine of the tonic effect of neurotransmitter release would permit receptor upregulation. The positive inotropic responses of paced left atria and papillary muscles and the positive chronotropic responses of spontaneously beating right atria were recorded. A concentration-response curve to isoprenaline (beta-adrenoceptor-mediated) was followed, in the presence of beta-blockade, by one to methoxamine (alpha-adrenoceptor-mediated). Methoxamine exerted positive inotropy of left atria and papillary muscles, the maxima being 43.2 +/- 2.7 and 26.8 +/- 4.4% of the isoprenaline maxima. A small positive chronotropy (16.5 +/- 5.6% maximum) of right atria occurred. After pretreatment with reserpine (1.0 mg kg-1 i.p. daily) for 7 days, the three preparations displayed supersensitivity to isoprenaline, revealed as a significant displacement (P less than 0.05) of the concentration-response curves to the left of those for control rats. Reserpine pretreatment, however, had no effect on the sensitivity to methoxamine. The increase in beta-adrenoceptor sensitivity to isoprenaline after reserpine pretreatment was accompanied by a significant 41.3% increase (P less than 0.05) in the number of [3H]-dihydroalprenolol [( 3H]-DHA) binding sites (Bmax) in ventricular membranes, although the dissociation constant (KD) was unaffected. There were more alpha-adrenoceptor [3H]-prazosin binding sites in ventricular than atrial membranes. However, there was no difference in KD or Bmax between reserpine-pretreated and control tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial agonists at guinea-pig atrial beta-adrenoceptors display relaxation responses in the guinea-pig ileum independent of beta-adrenoceptor stimulation.

The beta-adrenoceptor mediated responses of oxyfedrine, ritodrine, tazolol, prenalterol, salbutamol and carteolol were examined on guinea-pig left and right atrial and ileal preparations. All agonists tested in left and right atrial preparations were partial agonists relative to isoprenaline. All agonists with the exception of salbutamol, which appeared a full agonist, produced relaxation responses significantly greater than isoprenaline in ileal preparations. The response to ritodrine in the ileum was not influenced by practolol, in a concentration which antagonized the responses of ritodrine in the right atria. The response of the ileum to beta-adrenoceptor antagonists of varying lipophyllicity was examined. Propranolol and pindolol both produced relaxation responses relative to their lipophyllicities. No relaxation was observed to atenolol, which exhibits very low lipophyllicity. It is concluded that beta-adrenoceptor agonists exhibit a substantial relaxation of guinea-pig ileum that is independent of beta-adrenoceptor stimulation.

Beta-adrenoceptor sensitivity of brown and white adipocytes after chronic pretreatment of rats with reserpine.

The effect of pretreatment with reserpine (1.0 mg/kg i.p. daily for 7 days) on beta-adrenoceptor-mediated responses has been measured in epididymal white and interscapular brown adipocytes, left atria and vas deferens of rats in order to investigate the classification of the receptors and whether they are innervated. Lipolysis was measured in adipocytes, and from the same rats, the beta 1-adrenoceptor-mediated positive inotropic responses of isolated paced left atria and beta 2-adrenoceptor-mediated inhibition of field stimulation-induced contraction of the vas deferens were examined. The agonists used were isoprenaline, oxyfedrine (atria only) and (except in brown adipocytes) ritodrine, which was a partial agonist in white adipocytes, atria and vas deferens. Atria and brown adipocytes exhibited beta-adrenoceptor supersensitivity after reserpine pretreatment, whereas vas deferens and white adipocytes did not. Reserpine-induced reductions in food intake and body weight did not appear to influence beta-adrenoceptor-mediated lipolysis, since restriction of the diet equivalent to that of reserpine-treated rats produced no change in white adipocyte sensitivity. Responses mediated via beta 1-, but not beta 2-adrenoceptors, display supersensitivity after chronic depletion of neuronal catecholamines with reserpine and this is evidence for innervation of this receptor subtype. Thus, atrial beta 1-adrenoceptors are assumed to be innervated, whereas vas deferens beta 2-adrenoceptors are not. The present results are consistent with histochemical evidence that brown, but not white, adipocyte beta-adrenoceptors are innervated. However, they are not compatible with conventional receptor classification studies, which suggest that rat brown and white beta-adrenoceptors are similar--either both beta 1 or both atypical.

Responses mediated via beta-1 adrenoceptors but not beta-2 adrenoceptors exhibit supersensitivity after chronic reserpine pretreatment.

The purpose of this study was to examine whether reserpine pretreatment induces supersensitivity of both beta-1 and beta-2 adrenoceptor-mediated responses. Guinea pigs received reserpine (0.5 mg kg-1 s.c. or i.p.) daily for 7 days. Isolated tissues were set up in the presence of phentolamine (5 microM) and metanephrine (10 microM) and the sensitivity to isoproterenol and, where possible, a partial agonist (ritodrine, salbutamol or prenalterol) was determined. The beta adrenoceptor-mediated responses were recorded as the increase in rate and tension of right and left atria, inhibition of carbachol-induced contractions of ileum, relaxation of aortic spirals contracted with histamine, inhibition of transmurally stimulated vas deferens and relaxation of tracheal spirals and lung strips with intrinsic tone. The atria exhibited supersensitivity after reserpine pretreatment (s.c. and i.p.) as a leftwards shift of the isoproterenol concentration-response curve and elevation of the prenalterol maximum response. The ileum was also supersensitive, but only when tissues from animals receiving i.p. reserpine were compared with shams, which themselves were subsensitive or when reserpine was administered s.c. The trachea was also supersensitive, but not the aorta, lung and vas deferens, the responses of which are mediated via beta-2 adrenoceptors. In contrast, beta-1 adrenoceptors are involved in the atrial, ileal and tracheal responses. Therefore, only responses mediated via beta-1 adrenoceptors exhibited reserpine-induced supersensitivity which supports the hypothesis that beta-1 but not beta-2 adrenoceptors receive a sympathetic innervation.

A physiological basis for subclassifying beta-adrenoceptors examined by chemical sympathectomy of guinea-pigs.

Chemical sympathectomy of guinea-pigs was induced by chronic pretreatment with 6-hydroxydopamine over a 20 day period. Control animals were sham injected with vehicle at the same times. Isolated tissues were removed from the animals and beta-adrenoceptor sensitivity assessed from cumulative concentration-response curves for isoprenaline, followed after wash-out by a partial agonist (salbutamol, ritodrine or prenalterol). The following responses were measured: increases in force and rate of contraction of left and right atria respectively, inhibition of carbachol-induced ileal contractions, relaxation of intrinsic tone of lung strips and tracheal spirals, inhibition of contractions of vas deferens and soleus muscle induced by field stimulation. Left and right atria and ileum from 6-hydroxydopamine-pretreated guinea-pigs exhibited supersensitivity to beta-adrenoceptor stimulation. This was measured as a leftwards shift of the concentration-response curve for isoprenaline and as an elevation of the partial agonist maximum response (relative to isoprenaline), when compared with tissues from sham-injected controls. The supersensitivity was assumed to be due to the loss of endogenous neurotransmitter release by chemical sympathectomy and specific for the beta-adrenoceptor. In contrast, lung strips, vas deferens and soleus muscle were not supersensitive. The responses of these tissues are thought to be mediated via beta 2-adrenoceptors whereas cardiac and ileal responses are beta 1-adrenoceptor mediated. The latter receptor subtype would therefore appear to be under the influence of sympathetic innervation, but since no supersensitivity occurred at beta 2-adrenoceptors these were presumed to be non-innervated but stimulated by circulating adrenaline. These results obtained by use of chemical sympathectomy with 6-hydroxydopamine support the contention that the physiological basis of beta-adrenoceptor subclassification is that the beta 1-subtype are innervated whereas the beta 2-subtype are non-innervated.

Alpha- and beta-adrenoceptor-mediated responses of the guinea-pig ileum and the effects of neuronal uptake inhibition.

The effects of noradrenaline and isoprenaline were examined on preparations of guinea-pig ileum, in which contractions were induced by three different methods; by transmural electrical stimulation, by exogenous carbachol and by potassium depolarization. Alpha- or beta-adrenoceptor-mediated responses were examined by construction of cumulative concentration-response curves in the presence of propranolol (10(-6) M) and phentolamine (5 X 10(-6) M) respectively. Stimulation of alpha-adrenoceptors by noradrenaline virtually abolished the twitches from transmural stimulation, but only partially inhibited the carbachol- and potassium-induced contractions. The effects on the last two preparations were attributed to a post-synaptic inhibition at alpha-adrenoceptors on the longitudinal smooth muscle. In the transmurally-stimulated preparation there was an additional pre-synaptic alpha-adrenoceptor-mediated inhibition of cholinergic transmission. The maximum beta-adrenoceptor-mediated inhibition of all three preparations to noradrenaline and isoprenaline was of the same magnitude and attributed only to a post-synaptic action on longitudinal smooth muscle. The predominant post-synaptic beta-adrenoceptor-mediated (carbachol-contracted ileum) and pre-synaptic alpha-adrenoceptor-mediated (transmurally-stimulated ileum) relaxations were significantly (P less than 0.05) potentiated by the neuronal uptake inhibitor desmethylimipramine. These receptors may therefore be considered to be closely associated with the sympathetic innervation. The effect on the post-synaptic alpha-adrenoceptor-mediated relaxation was equivocal. Additional minor excitatory responses were identified as a direct alpha-adrenoceptor-mediated contractile response to noradrenaline and as a beta-adrenoceptor-mediated potentiation of transmural stimulation by isoprenaline, possibly due to facilitation of cholinergic transmitter release.

The use of forskolin to investigate the site of cardiac beta-adrenoreceptor supersensitivity.

The positive inotropic responses of left atria and papillary muscles and the positive chronotropic responses of right atria of guinea-pigs to isoprenaline and forskolin were examined. An increase in sensitivity of the three preparations to isoprenaline was observed by lowering the bath temperature from 38 to 30 degrees C as demonstrated by a leftwards shift of the concentration-response curves. A similar degree of supersensitivity was observed for forskolin. Since forskolin is reputed to stimulate adenylate cyclase directly, whereas isoprenaline stimulates via the regulatory nucleotide Ns protein, this would suggest a common site for the supersensitivity at adenylate cyclase. However, the possibility that forskolin also stimulates via the Ns protein in producing cardiac stimulation and that this is the site of hypothermia-induced supersensitivity is discussed. Supersensitivity to isoprenaline was also observed in left atria and papillary muscles from guinea-pigs chronically pretreated with reserpine for 3 days (5 mg/kg at 72 h, 3 mg/kg at 48 and 24 h) or 7 days (0.1 mg/kg daily). In the same tissues, there was no change in the sensitivity to forskolin. The site of the supersensitivity can therefore be concluded to occur before the level of adenylate cyclase activation either directly or via the regulatory Ns protein; possibly at the beta-adrenoreceptor itself.

Cardiac postjunctional supersensitivity to beta-agonists after chronic chemical sympathectomy with 6-hydroxydopamine.

The sensitivity to sympathomimetic amines of isolated atria removed from sham-injected and 6-hydroxydopamine-treated (6-OHDA) guinea-pigs was examined in the presence of an extraneuronal uptake blocker and an alpha-adrenoceptor antagonist. Three weeks of pretreatment with 6-OHDA resulted in leftwards shifts of the dose-response curves for the positive chronotropic and inotropic responses of right and left atria to isoprenaline. The responses to the partial agonist salbutamol were also potentiated after 6-OHDA pretreatment, revealed as an increase in the maximum response relative to isoprenaline. The supersensitivity was post-synaptic in origin and independent of changes in disposition or metabolism, since it was observed with agonists immune to neuronal uptake and O-methylation, and in the presence of extraneuronal uptake inhibition by metanephrine. It was also specific for the beta-adrenoceptor, no supersensitivity to histamine being found. In the right atria, the supersensitivity was partially masked by an opposing depressant effect after 6-OHDA pretreatment which was observed with histamine. Dissociation constants (KA) for the left atrial inotropic responses to orciprenaline were determined by use of the antagonist Ro 03-7894. Atria from 6-OHDA-pretreated animals were supersensitive to orciprenaline, but the KA value did not differ from that after sham injection. It could therefore be concluded that the increase in sensitivity was not due to an increase in affinity for the beta-adrenoceptor.

Characterization of beta-adrenoceptors mediating relaxation of the guinea-pig ileum.

Relaxation responses to sympathomimetic amines were recorded in potassium-contracted segments of guinea-pig ileum. Experiments were performed in the presence of phentolamine (5 X 10(-6) M) to eliminate beta-adrenoceptor-mediated effects. Metanephrine (10(-5) M) and desmethylimipramine (5 X 10(-7) M) were also present to prevent extraneuronal and neuronal uptake respectively. A potency order (-)-isoprenaline greater than (-)-noradrenaline greater than (-)-adrenaline was established, indicating a beta 1-adrenoceptor involvement for this relaxation. The potency of salbutamol (beta 2-selective) relative to isoprenaline in the ileum compared closely with its relative potency in isolated cardiac tissues (beta 1) but differed significantly from the value in lung parenchymal strips and vas deferens (beta 2). The pA2 values for antagonism of selective agonists (-)-noradrenaline (beta 1-selective) and fenoterol (beta 2-selective) by practolol (beta 1-selective) were identical, indicating a single beta 1-adrenoceptor population. The pA2 values for antagonism of these agonists by ICI 118,551 (beta 2-selective) were also identical and compatible with a beta 1-adrenoceptor population. Relaxation of the guinea-pig ileum is therefore mediated via a homogeneous population of beta 1-adrenoceptors.

Mechanisms of cardiac supersensitivity to sympathomimetic amines.

Supersensitivity of the beta-adrenoceptor-mediated positive inotropic and chronotropic responses of the heart to sympathomimetic amines is considered. The various types of supersensitivity of both pre- and post-synaptic origins are described and the possible mechanisms involved are discussed. Emphasis is given to the supersensitivity that arises from depletion of sympathetic catecholamine stores by reserpine and 6-hydroxydopamine. Results are presented which indicate that in both cases the supersensitivity develops slowly, is specific for the beta-adrenoceptor and is not associated with an increase in affinity of agonists for the receptor. Radioligand binding data is presented to show that there is no increase in the total number of beta-adrenoceptor binding sites in membrane fractions from ventricular homogenates of animals receiving reserpine. A review of the literature on binding studies indicates two opposing views with respect to the effects of reserpine on beta-adrenoceptor binding sites, one showing no change and the other showing an increase in total binding sites. Limited studies in the literature show that 6-hydroxydopamine may increase the number of sites. Binding data therefore remains inconclusive and must be interpreted with caution. The relationship between the development of depletion-induced supersensitivity and the innervation of the tissue and its receptor type is discussed.