SOFA--an open source framework for medical simulation

SOFA is a new open source framework primarily targeted at medical simulation research. Based on an advanced software architecture, it allows to (1) create complex and evolving simulations by combining new algorithms with algorithms already included in SOFA; (2) modify most parameters of the simulation--deformable behavior, surface representation, solver, constraints, collision algorithm, etc.--by simply editing an XML file; (3) build complex models from simpler ones using a scene-graph description; (4) efficiently simulate the dynamics of interacting objects using abstract equation solvers; and (5) reuse and easily compare a variety of available methods. In this paper we highlight the key concepts of the SOFA architecture and illustrate its potential through a series of examples.

Persistent and moderate hypercalcemia related to an ovarian clear cell adenocarcinoma: Pre- and postoperative parathyroid hormone related-peptide and 1,25-dihydroxyvitamin D3 levels

OBJECTIVE

To evaluate the role of PTH-related peptide (PTH-rP) and 1,25-dihyhydroxyvitamin D3 in a case of hypercalcemia related to an ovarian adenocarcinoma.

DESIGN

We report a case of humoral hypercalcemia in a patient aged 74 yr with a clear cell adenocarcinoma of the right ovary at an early stage of its development (stage T1aN0M0) revealed by moderate and persistent hypercalcemia (variable level between 2.7 and 3.2 mmol/l without any treatment) over six months.

METHODS

PTH-rP and 1,25-dihydroxyvitamin D3 were measured in blood samples taken before and after hysterectomy and bilateral salpingooophorectomy and in blood samples taken intraoperatively from the right ovarian vein and a peripheral vein.

RESULTS

High levels of plasma PTH-rP and 1,25-dihydroxyvitamin D3 concomitant with high serum calcium and low PTH levels were found before surgery, which was followed by normalisation of all parameters studied. A concentration gradient was found regarding plasma PTHrP (right ovarian vein 60.4 pmol/l, peripheral vein 4.5 pmol/l), not 1,25-dihydroxyvitamin D3.

CONCLUSION

1) moderate and persistent hypercalcemia can be observed at an early stage of an ovarian carcinoma; 2) the gradient of PTH-rP concentration between the samples taken from the right ovarian vein and a peripheral vein provides evidence for a direct secretion of PTH-rP by the ovarian tumor; 3) the increased 1,25-dihydroxyvitamin D3 level is not related to a direct ovarian production, but is a consequence of PTH-rP secretion.

Calorie restriction induces mitochondrial biogenesis and bioenergetic efficiency

Age-related accumulation of cellular damage and death has been linked to oxidative stress. Calorie restriction (CR) is the most robust, nongenetic intervention that increases lifespan and reduces the rate of aging in a variety of species. Mechanisms responsible for the antiaging effects of CR remain uncertain, but reduction of oxidative stress within mitochondria remains a major focus of research. CR is hypothesized to decrease mitochondrial electron flow and proton leaks to attenuate damage caused by reactive oxygen species. We have focused our research on a related, but different, antiaging mechanism of CR. Specifically, using both in vivo and in vitro analyses, we report that CR reduces oxidative stress at the same time that it stimulates the proliferation of mitochondria through a peroxisome proliferation-activated receptor coactivator 1 alpha signaling pathway. Moreover, mitochondria under CR conditions show less oxygen consumption, reduce membrane potential, and generate less reactive oxygen species than controls, but remarkably they are able to maintain their critical ATP production. In effect, CR can induce a peroxisome proliferation-activated receptor coactivator 1 alpha-dependent increase in mitochondria capable of efficient and balanced bioenergetics to reduce oxidative stress and attenuate age-dependent endogenous oxidative damage.

(1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone

The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

Assessment of glomerular and tubular functions in renal transplant patients receiving cyclosporine A in combination with either sirolimus or everolimus

AIMS

The aim of this study was to examine the glomerular filtration rate (GFR) and tubular function at three months after renal transplantation in two groups of patients receiving cyclosporine A associated with either sirolimus (SRL) (n = 18) or everolimus (RAD) (n = 12), two structurally similar immunosuppressant drugs.

RESULTS

Donors' and recipients' characteristics and mean cyclosporine A trough levels were similar in the two groups. The mean sirolimus trough level was 12.01 +/- 1.6 ng/ml whereas the mean everolimus trough level was 4.23 +/- 0.36 ng/ml. GFR, equated by the clearance of inulin, was higher in RAD patients (64 +/- 4 ml. min- 1.1.73 m(-2)) than in SRL patients (49 +/- 4 ml.min(-1) .1.73 m(-2)) (p < 0.05). The significant difference in GFR between the groups was not affected by differences in mean arterial blood pressures, or by differences in daily prednisone dosages, cyclosporine trough levels, or SRL and RAD trough levels. Phosphatemia, renal phosphate threshold (TmPO4/ GFR ratio) and uric acid clearance were significantly lower in the SRL than in the RAD group, despite similar levels of parathyroid hormone. Finally, urinary acid excretion was significantly lower in the RAD group.

CONCLUSION

In conclusion, regarding nephrotoxicity, our preliminary data suggest that it seems to be preferable to combine cyclosporine with RAD rather than with sirolimus in renal transplant patients. However, long-term renal effects of this combination are still to be determined in a larger cohort.

Cyclosporine-a-based immunosuppression and renal functional reserve in organ-transplant patients

The glomerular filtration rate (GFR) may increase after oral protein overload or after an amino acid infusion. Renal functional reserve (RFR) is defined as the difference between the poststimulation and the baseline glomerular filtration rate. RFR has been studied in transplant patients. The results have been conflicting because RFR may be affected by donor age, the time from transplantation, the type of immunosuppression, the basal GFR, the body surface area, and the presence of calcium channel blocker therapy. We observed that during the first year posttransplantation renal recipients maintained on cyclosporine (CsA) therapy retain a level of RFR that represents approximately 30% of the baseline GFR. Moreover, hypertensive cyclosporine treated renal transplant patients on calcium channel blocker therapy do not exhibit permanent glomerular hyperfiltration until 8 months posttransplantation. Finally, both renal and heart transplant patients on cyclosporine therapy possess renal reserve, but the single renal graft in renal transplant patients shows a proportionally higher baseline GFR and a better ability to exhibit a RFR than the two native kidneys in heart transplant patients. Many studies, although not all, have documented a positive RFR in both children and adult cyclosporine-treated kidney graft recipients, demonstrating that hyperfiltration is not the rule following single kidney transplantation.

A comparison of the effects of tamsulosin and alfuzosin on neurally evoked increases in bladder neck and seminal vesicle pressure in rats

OBJECTIVE

To assess the effects of the alpha 1-adrenoceptor antagonists alfuzosin and tamsulosin on the physiological events associated with ejaculation in the rat, because when these drugs are used for treating symptomatic benign prostatic hyperplasia in men they may affect ejaculation by impairing bladder neck closure and seminal vesicle contraction.

MATERIALS AND METHODS

In clinical trials the incidence of ejaculatory disorders in men is typically < 1% with alfuzosin and 4-18% with tamsulosin. The effects of tamsulosin and alfuzosin on bladder neck and seminal vesicle pressures (BNP and SVP) in the rat were analysed. Increases in BNP and SVP were induced in urethane-anaesthetized. Wistar rats by electrical stimulation (ES) of the hypogastric nerve (HN) before and after an intravenous injection with vehicle, 3 or 10 micrograms/kg of tamsulosin or alfuzosin (10 rats/group). The mean amplitude and area under the curve (AUC) of the BNP and SVP were expressed as the percentage of the response to ES of HN before the treatment.

RESULTS

The amplitude and AUC of the SVP were significantly decreased by both doses of tamsulosin, and marginally decreased by the same doses of alfuzosin. The amplitude of the BNP was significantly decreased by 3 and 10 micrograms/kg of tamsulosin and 10 micrograms/kg alfuzosin, and marginally decreased by 3 micrograms/kg alfuzosin. The AUC of the BNP was significantly decreased by both doses of tamsulosin, but barely affected by alfuzosin at the same doses.

CONCLUSION

Over the doses assessed, alfuzosin had significantly less deleterious effect on increases in BNP and SVP induced by ES of the HN than had tamsulosin.

Pseudo-isolated FSH deficiency caused by an inhibin B-secreting granulosa cell tumour: case report

Isolated FSH deficiency due to a mutation in the FSHbeta subunit is characterized by an extremely low serum FSH concentration. We report a patient who presented with an FSH of 0.8 mIU/ml and infertility associated with anovulation. Endocrinological assessment and immunohistochemistry revealed that a granulosa cell tumour was secreting inhibin B and suppressing FSH; however, LH and estradiol were within their normal ranges. Upon removal of the tumour, inhibin B decreased and FSH levels rose to normal values. The patient subsequently conceived and delivered successfully. Based on this case and on those previously described in the literature, we suggest that inhibin B levels should be evaluated in anovulatory patients having a clinical presentation consistent with functional hypothalamic amenorrhoea and very low to normal values of FSH.

Selegiline enhances erectile activity induced by dopamine injection in the paraventricular nucleus of the hypothalamus in anesthetized rats

Apomorphine delivered in the paraventricular nucleus of the hypothalamus (PVN) induces penile erection in rats, suggesting a role of dopaminergic projection to the PVN in the control of penile erection. We assessed whether the selective inhibitor of monoamine oxidase B, selegiline, could enhance the erectile activity induced by dopamine delivery in the PVN. Intracavernous and blood pressure (ICP and BP) were monitored in anesthetized rats to quantify ICP rises (number and percentage of ICP maximum/mean BP (ICPmax/BP x 100)) elicited by 10 micro g dopamine injection in the PVN after saline or 3 mg/kg i.v. selegiline (8 rats per group). The number of ICP rises (mean+/-s.d.: 4.5+/-2.9 vs 1.4+/-1.9; P=0.017) and their ICPmax/BP x 100 (49+/-8% vs 34+/-9%; P=0.015) were significantly greater upon dopamine injection in the PVN than upon vehicle. Compared to saline i.v., 3 mg/kg selegiline pretreatment significantly increased the number of ICP rises induced by dopamine injection in the PVN (9.4+/-2.6 vs 4.5+/-2.9; P<0.001), without affecting their amplitude. This suggests that drugs potentiating dopaminergic responses in the central nervous system might enhance proerectile commands of supraspinal origin.

Oligodendroglial expression of Edg-2 receptor: developmental analysis and pharmacological responses to lysophosphatidic acid

Edg-2 is a member of the G-protein-coupled seven-transmembrane receptor family recently identified in oligodendrocytes. Here we show that both in vitro and in vivo, Edg-2 transcripts are not detected during early stages of oligodendroglial development, but are expressed only in mature oligodendrocytes, shortly before the onset of myelination. Lysophosphatidic acid (LPA) has been reported to be a ligand of Edg-2 receptor in different cell types. However, in oligodendroglial cultures, LPA had no effect on survival, maturation, or cytoskeleton organization. In myelinating oligodendrocyte-neuron cocultures, LPA did not influence myelinogenesis. In addition, LPA failed to induce Ca2+ mobilization and had no effect on forskolin-induced cAMP accumulation. Phosphorylation of the ERK1/ERK2 MAP kinases was the only response elicited by LPA in oligodendrocytes. Therefore, in contrast to other cell types, in which LPA exerts pleiotropic effects, Edg-2-positive postmitotic oligodendrocytes display a restricted responsiveness to LPA.

Elevated serum Her-2/neu level predicts decreased response to hormone therapy in metastatic breast cancer

PURPOSE

To determine the effect of elevation of serum HER-2/neu on response to hormone therapy.

PATIENTS AND METHODS

Seven hundred nineteen metastatic patients with estrogen receptor-positive (ER(+)), progesterone receptor-positive, or both or ER status unknown breast cancer were randomized in three independent clinical trials to receive second-line hormone therapy with either megestrol acetate or an aromatase inhibitor (fadrozole or letrozole). An automated enzyme-linked immunosorbent assay specific for the extracellular domain of the HER-2/neu (c-erbB-2) oncoprotein product was used to detect serum levels.

RESULTS

Two hundred nineteen patients (30%) had elevated serum HER-2/neu protein levels, using the mean + 2 SD (15 ng/mL) from the serum of healthy women as an upper limit. Response to treatment was available for 711 patients. The response rate (complete responses plus partial responses plus stable disease) to endocrine therapy was 45% in 494 patients with non-elevated and 23% in 217 patients with elevated serum HER-2/neu levels (P <.0001). Median duration of treatment response (using the time to progression [TTP] variable for patients who responded) was shorter in the group with elevated serum HER-2/neu levels (11.7 months) compared with the patient group with non-elevated levels (17.4 months). TTP, time to treatment failure, and median survival (17.2 months v 29.6 months) were also significantly shorter in the patients with elevated serum HER-2/neu levels (P <.0001).

CONCLUSION

Patients with ER(+) and serum HER-2/neu-positive metastatic breast cancer are less likely to respond to hormone treatment and have a shorter duration of response than ER(+) and serum HER-2/neu-negative patients. Their survival duration is also shorter.

Apomorphine SL (Uprima): preclinical and clinical experiences learned from the first central nervous system-acting ED drug

An exclusive central site of action for the proerectile effect of apomorphine, including not only the brain but also the spinal cord, is supported by extensive experimental data. Assuming that the mechanisms of action of apomorphine are similar in humans and animal models, its use for the treatment of erectile dysfunction (ED) validates the emerging idea that erectile response could be enhanced by acting directly within the central nervous system (CNS). It also emphasized the key role of the dopaminergic system in the control of erection. As exemplified with the clinical development of apomorphine, targeting the CNS does not rule out the occurrence of undesirable side effects. Because the rare event of syncope induced by apomorphine is not well understood, further research should be conducted to explore its possible mechanisms. In clinical practice, however, approved doses of apomorphine SL are well tolerated. It is noteworthy that no modification of sexual desire was observed with apomorphine. Indeed, drugs acting within the CNS may more likely interact with sexual desire than peripherally acting drugs, and care should be taken to assess this point in the future. Although our knowledge of the control of penile erection by the CNS is restricted, there are many potential sites for CNS-acting ED drugs. New centrally acting therapy for ED should concentrate on receptor targets more specific to erectile command. Clinical efficacy of new centrally-acting compounds will assess the well-founded purpose of this rationalization.

ACE inhibitor-induced angioedema of the intestine: Case report, incidence, pathophysiology, diagnosis and management

A case report of fosinopril-induced angioedema of the intestine with a chronic course accompanied by multiple acute exacerbations is described. Angiotensin-converting enzyme (ACE) inhibitor-induced angioedema of the intestine (AIAI) occurs in a minority of patients taking an ACE inhibitor. The clinical presentation encompasses acute abdominal symptoms, pronounced bowel edema and ascites with occasional facial and/or oropharyngeal swelling. AIAI is diagnosed based on the temporal relationship between the symptomatic presentation and drug use, absence of alternative diagnoses including other causes of angioedema, and the prompt resolution of symptoms upon discontinuation of the ACE inhibitor. Prompt radiological investigation (abdominal computerized tomography and/or ultrasound) is critical in making an early diagnosis and in preventing unnecessary surgical intervention. There is a female predominance of AIAI, which may reflect the interaction of estradiol with the various pathways involved in the pathophysiology of AIAI. Management of AIAI consists mainly of conservative measures and discontinuation of the ACE inhibitor. Angiotensin II receptor antagonists should not be considered as appropriate alternatives. Awareness and knowledge of AIAI are important because of the increasing use of ACE inhibitors, current delays in making the diagnosis, obvious management strategies once the diagnosis is made and the dysutility of alternative diagnoses, which may lead to considerable morbidity. AIAI must be considered in patients taking ACE inhibitors who develop gastrointestinal complaints irrespective of the duration of the therapy.

Central nervous system agents in the treatment of erectile dysfunction: how do they work?

Drugs acting within the central nervous system (CNS) that reduce the sympathetic antierectile flow and enhance the parasympathetic proerectile flow to the penis may restore penile erection in cases of erectile dysfunction of both psychogenic and organic origin. The best characterized of such drugs is the dopaminergic agonist apomorphine, which acts on the hypothalamus and, perhaps, the autonomic nuclei in the spinal cord. Other drugs that target the CNS and have been registered and tested are the a(2)-adrenoceptor antagonists yohimbine and delequamine, the alpha-melanocyte-stimulating hormone agonist melanotan II, and the serotonin reuptake inhibitor trazodone. Androgens also may influence sexual behavior by acting within the CNS, notably by modifying the neurotransmitter system targeted by these drugs. Our knowledge of the mode of action of CNS drugs comes mainly from experiments on rodents. Consequently, explanations regarding the way they work in humans are only speculative.

Dopamine and male sexual function

The use of the D1/D2 dopamine receptor agonist apomorphine for the treatment of erectile dysfunction provides strong support in favor of a participation of the dopaminergic system in the control of sexual function. However, the exact involvement of dopamine in the control of sexual motivation and genital arousal in males is unknown. Experimental data in male rats suggested an implication of dopamine in sexual motivation as well as in copulatory performance. Specific tests allowing assessment of sexual motivation showed that the release of dopamine at the level of the nucleus accumbens (innervated by the mesolimbic dopaminergic pathway) and the medial preoptic area of the hypothalamus (innervated by the dopaminergic incertohypothalamic pathway) positively regulated the anticipatory/motivational phase of copulatory behavior. A permissive role of dopamine released at the level of the median preoptic area of the hypothalamus in the display of copulatory behavior has also been demonstrated. It is noteworthy that these participations of the dopaminergic system are not specific for sexual behavior but rather reflect the involvement of dopamine in the regulation of cognitive, integrative and reward processes. Because of its role in the control of locomotor activity, the integrity of the nigrostriatal dopaminergic pathway is also essential for the display of copulatory behavior. Somehow more specific to sexual function, it is likely that dopamine can trigger penile erection by acting on oxytocinergic neurons located in the paraventricular nucleus of the hypothalamus, and perhaps on the pro-erectile sacral parasympathetic nucleus within the spinal cord. In conclusion, central dopamine is a key neurotransmitter in the control of sexual function.

Does histologic grade have a role in the management of head and neck cancers?

PURPOSE

High histologic grade is usually associated with a greater propensity to distant metastases (DM). Its role to predict DM in head and neck cancer is not yet defined. The aim of this study is to evaluate the role of histologic grade as an independent predictor of DM and to determine a subgroup of patients who may benefit from systemic chemotherapy.

PATIENTS AND METHODS

This is a retrospective study of 1,266 consecutive patients treated by definitive or postoperative radiotherapy between 1989 and 1997. All patients received at least 50 Gy. All stages and subsites of head/neck were included. DM rates were evaluated by the Kaplan-Meier method with a subsequent Cox analysis.

RESULTS

There is a strong correlation of grade with N stage (P <.000001). The metastases-free survival (MFS) was 98%, 90%, and 72% for grades 1, 2, and 3, respectively (P <.000001). In patients with N0 stage, MFS is always greater than 90%, whatever the grade. In the 222 N1 patients, MFS was more than 90% in grade 1 and 2 but dropped to 75% for grade 3 (P =.001). In patients with N2 and N3, MFS was 91%, 79%, and 59% for grades 1, 2, and 3, respectively (P =.008). The same conclusion is applicable when only patients with neck control are analyzed. In a Cox model, grade was an independent predictor of DM (P =.000001) as well as T stage (P =.003), N stage (P =.000001), and neck failure (P =.0003). Higher grade was also an independent predictor of survival (P =.02).

CONCLUSION

Patients with histologic grade 1 and grade 2 (except N3) are at low risk of DM. Patients with grade 2 and N3 or patients with grade 3 and N1 to N3 have a higher risk of distant metastases and should be considered for systemic treatment.

Dopamine and sexual function

The use of the D1/D2 dopamine receptor agonist apomorphine SL for the treatment of erectile dysfunction provides a strong support in favour of a participation of the dopaminergic system in the control of sexual function. However, the exact involvement of dopamine in sexual motivation and in the control of genital arousal in humans is unknown. In contrast, experimental data suggest an implication of dopamine at all these stages of the copulatory behaviour in rodents. The release of dopamine at the level of the nucleus accumbens, which is innervated by the mesolimbic dopaminergic pathway originating in the ventral tegmental area, is positively implicated in the pre-copulatory or appetitive phase in male rats. There is also a permissive role in the copulatory or consumatory phase for dopamine released at the level of the median pre-optic area, which receives projection from the dopaminergic incertohypothalamic pathway within the hypothalamus. It is noteworthy that these participations of the dopaminergic system are not specific to sexual behaviour but rather reflect the more general involvement of dopamine in the regulation of cognitive, integrative and reward processes. Due to its role in the control of locomotor activity, the integrity of the nigrostriatal dopaminergic pathway is also essential for the display of copulatory behaviour. Somehow more specific to sexual function, it is likely that dopamine can trigger penile erection by acting on oxytocinergic neurons located in the paraventricular nucleus of the hypothalamus, and perhaps on the pro-erectile sacral parasympathetic nucleus within the spinal cord. The counterpart of such regulation of the genital arousal by dopamine has not yet been established in females. In conclusion, the central dopaminergic system is a key element of the control of sexual function.

Vaginal physiological changes in a model of sexual arousal in anesthetized rats

The understanding of the pathophysiology of female sexual dysfunction suffers from the lack of a convenient model for the study of female genital sexual response. In this study, systemic arterial blood pressure (BP) as well as partial oxygen tension, temperature, and blood engorgement of the vagina [using laser-Doppler flowmetry in arbitrary units (AU)] were measured in anesthetized, ovariectomized (1 wk before the start of the experiment) female rats. Vaginal sexual arousal was replicated by electrical stimulation of the pelvic nerve (PNS). PNS induced reproducible increases in the different vaginal parameters (from baseline value, respectively: 16 +/- 10 to 30 +/- 12 mmHg; 34.9 +/- 0.6 to 36 +/- 0.6 degrees C; 450 +/- 196 to 1,500 +/- 360 AU; P < 0.05, paired t-test) and BP (90 +/- 7 to 123 +/- 13 mmHg, P < 0.05, paired t-test). Vaginal vascular resistance was significantly decreased during PNS (from 0.23 +/- 0.15 to 0.08 +/- 0.02 mmHg/AU). Vaginal wall tension was also measured with a force transducer. PNS induced an increase in vaginal wall tension (1.0 +/- 0.2 g), followed by a decrease under the prestimulation value. Intravenous atropine sulfate (1 mg/kg) injection abolished the increase in vaginal wall tension without significantly affecting vaginal vascular resistance. Intravenous vercuronium bromide (2 mg/kg) injection abolished the decrease in vaginal wall tension. Concomitant electrical stimulation of the paravertebral sympathetic chain inhibited vaginal response induced by PNS. Electrical stimulation of the medial preoptic area of the hypothalamus induced a response qualitatively equivalent to PNS with a significant decrease of vaginal vascular resistance. These data support that vaginal contractions involve both smooth and striated muscles and indicate that neural control of vaginal sexual arousal have great similarities in male and female rats.

Non-AT(1)-receptor-mediated protective effect of angiotensin against acute ischaemic stroke in the gerbil

Previous studies have shown that angiotensin II (Ang II), by mediating rapid recruitment of collateral circulation, has a protective effect in the setting of acute ischaemia. In an experimental model of acute cerebral ischaemia in the gerbil, Fernandez et al. have reported that the mechanism of the protective effect of Ang 11 is blood pressure (BP)-independent, and that the AT1-receptor antagonist, losartan, but not the ACE inhibitor (ACE-I),enalapril, decreases mortality following unilateral carotid artery ligation. The aim of this study was to examine there producibility of the respective effects of losartan and enalapril, and to verify that these differential effects are drug class-related. Acute cerebral ischaemia was induced in anaesthetised gerbils bv unilateral carotid ligation. The effect of pretreatment with two different ACE-I(enalapril and lisinopril), and two different AT1-receptor antagonists (losartan and candesartan), administered orally or intravenously, on mortality were compared. Kaplan-Meier survival curves at day three were analysed bv a log-rank test. Pretreatment with both enalapril and lisinopril significantly decreased survival at day three compared with controls, while the AT1-receptor antagonists losartan and candesartan, despite similarly lowering BP, did not increase mortality. Coadministration of losartan and enalapril increased mortality to the same extent as enalapril alone. This study confirms that Ang II contributes to protective mechanisms against acute cerebral ischaemia through non AT1-receptor-mediated, BP-independent effects.

Efficacy of a clinical medication review on the number of potentially inappropriate prescriptions prescribed for community-dwelling elderly people

BACKGROUND

The administration of many drugs concurrently to elderly patients is a well-known problem in geriatrics and involves numerous risks. One way to reduce polypharmacy is to provide information to physicians in order to modify their prescribing practices. The main objective of this study was to evaluate the impact of an intervention program that targeted physicians with the aim of reducing the number of potentially inappropriate prescriptions (PIPs) given to elderly patients.

METHODS

A randomized controlled trial was carried out among community-dwelling elderly people in Sherbrooke, Que. The participants were 266 patients over 75 years of age (experimental group: n = 136, control group: n = 130). A team comprising 2 physicians, a pharmacist and a nurse reviewed the list of drugs and the diagnoses of a subgroup of the experimental group in a case conference. Suggestions were formulated and mailed to the patients' physicians together with relevant scientific documentation justifying the recommendations. The main outcome measure was the number of PIPs.

RESULTS

The mean number of PIPs per patient declined by 0.24 in the experimental group (n = 127) and by 0.15 in the control group (n = 116). The decline in PIPs was even larger in the experimental group that had case conferences (n = 80), in which the mean number of PIPs per patient declined by 0.31. However, this difference between the experimental group and the control group was not statistically significant in the intent-to-treat analysis. The number of drugs prescribed was not modified by the intervention, nor were the results of the global assessment of the patients' drug profiles.

INTERPRETATION

This study suggests that the intervention program had no effect on the prescribing of PIPs.

Spinal proerectile effect of apomorphine in the anesthetized rat

Considering the presence of dopaminergic receptors in the lumbosacral spinal cord, we tested whether apomorphine could exert a proerectile effect by acting at the spinal level. Intracavernous (ICP) and blood pressures (BP) were measured in anesthetized rats. ICP rises were quantified (duration, percentage of ICPmaximum/meanBP (ICPmax/BPx100), area under ICP curve (AUC/BP) and sum of AUC/BP after intravenous (i.v.) and intrathecal (i.t.) injections of apomorphine alone or in presence of i.t. oxytocin (10 ng). Both 10 and 30 microg i.v. apomorphine dosings elicited erectile events evidenced by ICP rises. Upon the 30 microg i.v. injection, duration of ICP rises were increased from 25+/-10 to 69+/-18 s (P<0.001), ICPmax/BPx100 from 21+/-3 to 50+/-14% (P=0.001), AUC/BP from 3+/-1 to 14+/-6 s (P=0.002) and sum of AUC/BP from 5+/-7 to 34+/-35 s (P=0.021). Upon 30 microg i.t. injections of apomorphine at the lumbosacral level, the number of ICP rises was increased from 0.2+/-0.4 to 3.0+/-1.5, ICPmax/BPx100 from 16+/-9 to 43+/-12 and sum of AUC/BP from 1+/-3 to 31+/-15 s compared to vehicle injection (P<0.05 for all parameters). Injection of 30 microg i.v. or i.t. apomorphine non-significantly enhanced the number and amplitude of the ICP rises induced by 10 ng i.t. oxytocin. However, the enhancement of the amplitude of the ICP rises elicited by i.t. oxytocin was more pronounced with i.t. apomorphine than with i.v. apomorphine. These results suggest the existence of a spinal site of action for apomorphine which may (1) participate to generation of erection and (2) exerts a facilitator effect on erection of supraspinal origin.

Covalent intermediate trapped in 2-keto-3-deoxy-6- phosphogluconate (KDPG) aldolase structure at 1.95-A resolution

2-Keto-3-deoxy-6-phosphogluconate (KDPG) aldolase catalyzes the reversible cleavage of KDPG to pyruvate and glyceraldehyde-3-phosphate. The enzyme is a class I aldolase whose reaction mechanism involves formation of Schiff base intermediates between Lys-133 and a keto substrate. A covalent adduct was trapped by flash freezing KDPG aldolase crystals soaked with 10 mM pyruvate in acidic conditions at pH 4.6. Structure determination to 1.95-A resolution showed that pyruvate had undergone nucleophilic attack with Lys-133, forming a protonated carbinolamine intermediate, a functional Schiff base precursor, which was stabilized by hydrogen bonding with active site residues. Carbinolamine interaction with Glu-45 indicates general base catalysis of several rate steps. Stereospecific addition is ensured by aromatic interaction of Phe-135 with the pyruvate methyl group. In the native structure, Lys-133 donates all of its hydrogen bonds, indicating the presence of an epsilon-ammonium salt group. Nucleophilic activation is postulated to occur by proton transfer in the monoprotonated zwitterionic pair (Glu-45/Lys-133). Formation of the zwitterionic pair requires prior side chain rearrangement by protonated Lys-133 to displace a water molecule, hydrogen bonded to the zwitterionic residues.