[Colchicum poisoning by confusion with wild garlic (Allium ursinum)]

INTRODUCTION

Colchicine poisoning is a life-threatening intoxication.

CASE REPORT

We report a case of food poisosing with Colchicum autumnale by confusion with wild garlic. The clinical presentation is the same as that of colchicine drug intoxication. The evolution can be fatal in case of massive ingestion. The proximity of the place of growth and their similar appearance in spring make Colchicum and wild garlic plants that can easily be confused.

CONCLUSION

Physicians have to be vigilant in case of dysenteric syndrome and biological disturbances in spring and look for the consumption of perennial plant preceding symptoms.

Red clover-rich grassland increases equol concentration in eggs from free-range laying hens

1. The aim of this study was to evaluate the production of equol (4',7-isoflavandiol; a bacterial polyphenol metabolite which is an isoflavandiol oestrogen metabolised from daidzein from plants) enriched eggs from free-range hens fed different pasture species. Four species were tested: red clover, white clover, ryegrass and chicory.2. The study was conducted from June to September 2017 on eight free range, outdoor areas, each containing fifteen laying hens and sown with a single pasture species3. Precursors of equol (daidzein, formononetin) were analysed every fortnight from the fresh pasture cover in each area, as well as equol and daidzein levels in eggs.4. Daidzein and formononetin concentrations in the fresh pasture samples differed significantly according to species (P < 0.001), whereby red clover had the highest concentrations of daidzein and formononetin (85 and 996 µg/g DM, respectively).5. Equol concentration in eggs differed according to pasture species (P < 0.001). Equol concentrations reached about 1,200 ng/g DM in eggs from hens with access to red clover. These eggs can represent a valuable source of equol in the human diet.

Towards speciation of organically bound tritium and deuterium: Quantification of non-exchangeable forms in carbohydrate molecules

An original methodology to quantitatively explore exchangeability of hydrogen isotopes in carbohydrate molecules is proposed. To access the speciation of organically bound hydrogen isotopes, isotopic exchanges were carried out under a soft path regime in the vapor phase at 20 °C with set (D,T/H) vapor pressure ratios. When steady states were reached, the fraction of exchangeable hydrogen of microcrystalline cellulose, alpha-cellulose and wheat grains were obtained and ranged from 13 to 31% (versus a theoretical value of 30%). In cellulose, and more specifically in microcrystalline cellulose, the molecular hydrogen bonds as well as the different conformations of the network seemed to decrease the hydroxyl groups of glucose units available for isotopic exchange. On the contrary, the assumed enzymatic hydrolysis of the constitutive molecules of wheat starch into low-molecular weight carbohydrate molecules enhanced the exchangeable pool. An average value of the activity between non-exchangeable organically bound tritium (NE-OBT) and non-exchangeable organically bound hydrogen was calculated for wheat grains, (TH)_NE  = 0.55 ± 0.03 Bq.g^-1 of hydrogen atoms.

Primary hepatic angiosarcoma and liver transplantation: Radiological, surgical, histological findings and clinical outcome

Angiosarcoma is a rare type of soft tissue sarcoma that accounts for less than 1% of all sarcomas and only 2% of all primary hepatic tumours. Thorotrast, arsenic, and vinyl chloride monomer are frequently listed as occupational exposure risks. The estimated latency is long (10-40 years) in occupational cases and very long (60 years or more) in non-occupational cases. The symptoms and CT-scan appearance of hepatic angiosarcoma (HAS) are non-specific. We present a case of a 65-year-old Caucasian male with history of cryptogenic cirrhosis, low alpha-foetoprotein levels and a single, 4-cm nodule of potential atypical hepatocellular carcinoma (no washout at MRI and CT-scan) in segment VIII. Laparoscopic radiofrequency ablation (a biopsy of the neoplastic lesion was technically impossible) was performed, followed by liver transplantation (LT) 6 months later. High-grade multifocal HAS was found in the explanted liver, with extensive involvement of the venous portal structures. No complications were observed during the postoperative course, and initial immunosuppression included tacrolimus, mycophenolate mofetil and corticosteroids. Because of the histological findings, tacrolimus was switched to everolimus as the main immunosuppressive drug one month after LT. Despite this conversion, the patient developed bone metastases 3 months after LT and peritoneal carcinosis one month later. This case report suggests that everolimus conversion does not inhibit the development of tumour metastases. Consequently, HAS remains an absolute contraindication to LT because of the poor outcome. If LT has been performed for incidental HAS, new molecular therapies (e.g. vascular endothelial growth factor antagonists) should be considered immediately after LT to improve the outcome.

Vagotomy prevents the effect of probiotics on caspase activity in a model of postmyocardial infarction depression

BACKGROUND

Myocardial infarction (MI) is associated with apoptosis in the amygdala and, ultimately, with clinical signs of depression. Different treatments have proven to be beneficial in preventing depression, including combination of the probiotics Lactobacillus helveticus and Bifidobacterium longum for prophylaxis. We have speculated previously that the benefit of these probiotics is due to their anti-inflammatory properties, and evidence suggests that an intact vagus nerve is important for this effect to occur. This study was designed to ascertain vagus nerve involvement in the beneficial influence of probiotics on caspase activities in our post-MI animal model of depression.

METHODS

Probiotics and/or vehicle were administered daily to male adult rats, 14 days before MI and until euthanasia. Vagotomy was performed in subgroups of rats 40 min before MI. They were sacrificed after 3 days of reperfusion, and MI size was assessed along with caspase-3 and -8 activities in the amygdala.

KEY RESULTS

Probiotics had no effect on infarct size but vagotomy increased it. Caspase-3 and caspase-8 activities in the amygdala were higher in MI than in sham-operated rats, and this outcome was reversed by probiotics. The beneficial influence of probiotics was abolished by vagotomy.

CONCLUSIONS & INFERENCES

Our data indicate that the effect of probiotics on caspase activities in the amygdala after MI depends on an intact vagus nerve.

Early-TIPSS placement prevents rebleeding in high-risk patients with variceal bleeding, without improving survival

BACKGROUND

Early-TIPSS (transjugular intrahepatic portosystemic shunt) placement may improve rebleeding and reduce 1-year mortality, compared to standard management in high-risk patients with cirrhosis and variceal bleeding.

AIM

To obtain external validation of this therapeutic approach.

METHODS

We performed a prospective study including all consecutive patients with Child-Pugh C 10-13 cirrhosis or Child-Pugh B with active bleeding at endoscopy admitted to our ICU between March 2011 and February 2013 for variceal bleeding. TIPSS were placed within 72 h after stabilisation. Patients were matched for gender, age, Child-Pugh score, MELD score and to patients from a historical cohort hospitalised before March 2011.

RESULTS

31/128 patients with cirrhosis (77.4% men, mean age 53.2 ± 9.0 years old, MELD score 20.9 ± 6.9, Child-Pugh C: 77.4%) admitted for acute variceal bleeding between March 2011 and February 2013 (TIPSS+ group) were matched to 31 historical patients (TIPSS- group). Uncontrolled bleeding occurred in 1/31 patients in the TIPSS+ group vs. 2/31 patients in TIPSS- group (P = 0.55). The 1-year probability of being free of rebleeding was higher in the TIPSS+ group (97% vs. 51%, P < 0.001). Actuarial 1-year survival was not different between the two groups (66.8 ± 9.4% vs. 74.2 ± 7.8%, P = 0.78). Acute cardiac failure occurred more frequently in the TIPSS+ group (25.8% vs. 6.4%, P = 0.03).

CONCLUSIONS

Early-TIPSS placement effectively prevents rebleeding in high-risk patients with variceal bleeding but does not significantly improve survival. This might be due to the high proportion of patients with Child-Pugh C cirrhosis in our series. Cardiac failure may play a role and must be investigated before the procedure, when possible.

Elective subtotal colectomy with ileosigmoid anastomosis for colon cancer preserves bowel function and quality of life

AIM

We report on our experience of elective subtotal colectomy and ileosigmoid anastomosis for colon cancer with focus on postoperative results, function and quality of life.

METHOD

Between 1998 and 2011, 106 consecutive patients with colonic malignancy underwent this procedure electively. Function and quality of life (EORTC QLQ-C30) were evaluated retrospectively with questionnaires sent to all patients free of recurrence.

RESULTS

There were 62 men and 44 women (mean age 63 years). Postoperative mortality and morbidity rates were 1.9 and 26.4%, respectively. Persistent ileus was the main early complication (16%). After a mean follow-up of 67 ± 36 months, 50 (78.1) out of 64 patients have been evaluated for function and quality of life. The mean number of bowel movements per 24 h was 3 ± 2 and significantly lower when the length of the remaining sigmoid colon was more than 15 cm (P = 0.049). Compared with a European reference population for EORTC QLQ-C30 results, our patients had significantly more diarrhoea (26 vs 3, P = 0.0002) but less pain (10 vs 25, P < 0.0001) and better global quality of life (77 vs 62, P < 0.0001).

CONCLUSION

Elective subtotal colectomy for colon cancer is safe and associated with good function and quality of life. Ileosigmoid anastomosis should be discussed when extended colectomy is required, providing the rectosigmoid junction and its vascular supply can be oncologically preserved. For tumours located in the transverse colon or at the splenic flexure, this procedure may be the best surgical option.

Vegephy: impact of vegetable oils used as extemporaneous additives on pesticide residues and their crop protection potential

Within the framework of the VEGEPHY project set up to assess the effect of refined oils used as extemporaneous additives, both alone and in combination with oligosaccharides (guar, xanthan and carboxymethyl cellulose), on the quality of plant protection treatments for wheat, a study was conducted on the effect of combinations of additives on the level of pesticide residues in wheat plants and grain and their impact on treatment efficiency. The use of some of these additives gave efficiency results that were comparable with those obtained with additives that are currently used but are not bio-based. The use of refined oils as extemporaneous additives, both alone and combined with oligosaccharides, led to better penetration by the pesticide as well as longer persistence of its activity. The experiments were conducted with fungicides, herbicides, plant growth regulators and various types of formulation (EC, SC and WG). The results obtained were conclusive, but they did depend on the physico-chemical properties of the active substance. The risk of exceeding the maximum residue levels (MRLs) of pesticides was also evaluated. Even where the MRLs had not been not exceeded, the experiments showed that in some cases the treatment with these additives could lead to pesticide residues up to two times higher than those measured for the treatment without additives. It would be necessary, therefore, to reduce the treatment dose associated with the additive and/or have a long enough pre-harvest interval to avoid exceeding the MRLs. The use of green additives could be a useful and easy way to attain the European Union (EU) goal of reducing pesticide use by improving the retention of active substances on the plant and reducing the number of treatments.

Peptic ulcer bleeding in patients with or without cirrhosis: different diseases but the same prognosis?

BACKGROUND

Physiopathology and prognosis of peptic ulcer bleeding (PUB) have never been described in cirrhotic patients.

AIM

To assess risk factors and outcome of PUB in two groups of patients with PUB with or without cirrhosis.

METHODS

We included prospectively all patients with PUB referred to our ICU of Hepatology and Gastroenterology between January 2008 and March 2011. All patients were treated according to international recommendations. Diagnosis of cirrhosis was based on clinical, biological and morphological exams. Aetiologies, characteristics and outcomes of PUB were compared in cirrhotic vs. noncirrhotic patients.

RESULTS

A total of 203 patients with PUB were included prospectively. Twenty-nine patients had cirrhosis (group Cirr+), and 174 patients had no cirrhosis (group Cirr-). Demographic data were similar between the two groups except for age and alcohol consumption. Aetiology of cirrhosis was alcohol in 97% of cirrhotic patients. Characteristics of PUB were not different between the two groups. Ninety-three per cent of patients with cirrhosis had endoscopic portal hypertension. Aetiology of PUB was different between the group Cirr+ and Cirr- (Helicobacter pylori = 10.3% vs. 48.8%, P < 0.0001; NSAID's = 17.2% vs. 54.0%, P < 0.0001; idiopathic PUB = 79.3% vs. 23.8%, P < 0.0001). Outcome was comparable concerning re-bleeding (7.0% vs. 6.9%, P = 0.31), need for arterial embolisation (10.3 vs. 8.6%, P = 0.76), need for salvage surgery (0 vs. 1.7%, P = 0.31) and mortality (3.0% vs. 1.1%, P = 0.87).

CONCLUSIONS

Physiopathology of PUB seems to be different in patients with cirrhosis. In cirrhotic patients, PUB occurs almost only in alcoholics. In our series, prognosis was similar to general population. PUB in cirrhosis might be related to portal hypertension and/or alcohol.

Peptic ulcer bleeding in patients with or without cirrhosis: different diseases but the same prognosis?

BACKGROUND

Physiopathology and prognosis of peptic ulcer bleeding (PUB) have never been described in cirrhotic patients.

AIM

To assess risk factors and outcome of PUB in two groups of patients with PUB with or without cirrhosis.

METHODS

We included prospectively all patients with PUB referred to our ICU of Hepatology and Gastroenterology between January 2008 and March 2011. All patients were treated according to international recommendations. Diagnosis of cirrhosis was based on clinical, biological and morphological exams. Aetiologies, characteristics and outcomes of PUB were compared in cirrhotic vs. noncirrhotic patients.

RESULTS

A total of 203 patients with PUB were included prospectively. Twenty-nine patients had cirrhosis (group Cirr+), and 174 patients had no cirrhosis (group Cirr-). Demographic data were similar between the two groups except for age and alcohol consumption. Aetiology of cirrhosis was alcohol in 97% of cirrhotic patients. Characteristics of PUB were not different between the two groups. Ninety-three per cent of patients with cirrhosis had endoscopic portal hypertension. Aetiology of PUB was different between the group Cirr+ and Cirr- (Helicobacter pylori = 10.3% vs. 48.8%, P < 0.0001; NSAID's = 17.2% vs. 54.0%, P < 0.0001; idiopathic PUB = 79.3% vs. 23.8%, P < 0.0001). Outcome was comparable concerning re-bleeding (7.0% vs. 6.9%, P = 0.31), need for arterial embolisation (10.3 vs. 8.6%, P = 0.76), need for salvage surgery (0 vs. 1.7%, P = 0.31) and mortality (3.0% vs. 1.1%, P = 0.87).

CONCLUSIONS

Physiopathology of PUB seems to be different in patients with cirrhosis. In cirrhotic patients, PUB occurs almost only in alcoholics. In our series, prognosis was similar to general population. PUB in cirrhosis might be related to portal hypertension and/or alcohol.

Effects of different dietary omega-6/3 polyunsaturated fatty acids ratios on infarct size and the limbic system after myocardial infarction

Changes in dietary omega-6/3 polyunsaturated fatty acids (PUFA) ratios affect anti- and proinflammatory equilibrium. As reperfused myocardial infarction (MI) is an inflammatory pathology that alters the cell integrity of the myocardium but also of other tissues, such as the hippocampus and amygdala, attenuation of the inflammation could be helpful in maintaining cell integrity after MI. Therefore, we hypothesized that a decrease in the dietary omega-6/3 PUFA ratio, without altering the diet content in total fat, proteins, or carbohydrates, will result in a reduction of infarct size and a diminution of postreperfusion apoptosis observed in the amygdala and hippocampus. Male Sprague–Dawley rats were fed 1 of 3 diets containing different omega-6/3 PUFA ratios for 2 weeks (5:1; 1:1; 1:5). Then, myocardial ischemia was induced by left anterior descending coronary artery occlusion for 40 min, followed by reperfusion. Cardioprotective mechanisms were studied in the myocardium at 15 min of reperfusion, along with myocardial infarct size after 24 h of reperfusion. Apoptosis was evaluated in the hippocampus and the amygdala. We found that infarct size was significantly reduced by 32% in groups 1:5 and 1:1 vs. group 5:1. Akt activity was higher in groups 1:5 and 1:1 compared with group 5:1. Caspase-3 enzymatic activity doubled in area CA1 and the dentate gyrus (DG) in group 5:1 compared with groups 1:1 and 1:5. In addition, caspase-8 enzymatic activity was increased in the DG at 24 h, and caspase-9 was enhanced in CA1 at 24 h in group 5:1 vs. groups 1:1 and 1:5. These results demonstrate that the increase in the dietary omega-3 PUFA, at the expense of omega-6 PUFA, reduces infarct size and helps to inhibit apoptosis in the limbic system after MI.

Coprecipitation of thorium with UO2

Coprecipitation may be a significant process in controlling radionuclide (RN) release during spent fuel dissolution/reprecipitation in a breached geological disposal site by water. The objective of this work was to study the coprecipitation of thorium with UO2 as host phase under reducing conditions (pure N2 and E h<-100 mV/SHE) as a function of pH and [Th]/[U] initial concentration ratio. For pH < 4, the final concentration of Th was found to be considerably lower than expected if pure phase, Th(OH)4(s) was formed. Coprecipitation phenomena and formation of solid solutions (U,Th)O2+x(s) are suggested to be responsible for the lower solubility concentrations. For pH > 4, the final concentrations seems to be similar to pure phase solubility.

Behavioural signs of depression and apoptosis in the limbic system following myocardial infarction: effects of sertraline

Depression is diagnosed in 15-30% of patients following myocardial infarction (MI) and this may also be observed in the rat. We measured the effects of the antidepressant sertraline on behavioural and biochemical events following MI in a rat model. Following surgery, MI rats and sham controls were treated with sertraline (10 mg/kg, i.p.) or saline. Subgroups of rats were tested for behavioural depression 14 days after surgery. Apoptosis was estimated in other rats by measuring caspase-3 activity and TUNEL positive cells (3 days after surgery) in limbic structures (amygdale, hippocampus, hypothalamus, frontal and prefrontal cortices). Bax/Bcl-2 ratio was measured 14 days after surgery. Behavioural signs of depression (decreased sucrose intake and forced swimming time) were found in saline-treated MI rats but not in sertraline-treated rats. Compared with controls, caspase-3 activity and TUNEL positive cells were significantly increased in most limbic structures of MI rats. High prefrontal Bax/Bcl-2 ratio in MI rats correlated with low forced swimming time. Apoptosis was not found in sertraline-treated MI rats. These results establish the bases of a rat model of depression following MI and show for the first time that a selective serotonin reuptake inhibitor prevents both behavioural and biochemical markers in this model.

[Late complications of a skin oesophagoplasty realized 45 years before: an historical case]

We report the case of a patient operated for the late complications of a skin-lined tube reconstruction of the esophagus performed 45 years ago. We recall the historical interest of this method for total esophageal reconstruction and emphasize the fact that it can still be a solution of last resort when intestinal tubes are no longer available.

Reduction of apoptosis in the amygdala by an A2A adenosine receptor agonist following myocardial infarction

It has been observed that a cytokine synthesis inhibitor, pentoxifylline, prevents the apoptotic processes taking place in the amygdala following myocardial infarction. However, it is unknown if the cardioprotective effect of A(2A) adenosine receptor agonist, CGS21680, which reduces cytokine synthesis, would lead to such amygdala apoptosis regression. Thus, this study was designed to investigate whether cardioprotective A(2A) adenosine receptor activation reduces apoptosis in the amygdala following myocardial infarction. Anesthetized rats were subjected to left anterior descending coronary artery occlusion for 40 min, followed by 72 h of reperfusion. The A(2A) agonist CGS21680 (0.2 mug/kg/min i.v.) was administered continuously for 120 min, starting (1) five minutes prior to instituting reperfusion (Early) or (2) five minutes after the beginning of reperfusion (Late). After reperfusion, myocardial infarct size was determined and the amygdala was dissected from the brain. Infarct size was reduced significantly in the Early compared to the Control group (34.6 +/- 1.8% and 52.3 +/- 2.8% respectively; p < 0.05), with no difference compared to the Late group (40.1 +/- 6.1%). Apoptosis regression was documented in the amygdala of the Early group by an enhanced phosphatidylinositol 3-kinase-Akt pathway activation and Bcl-2 expression concurrently to a caspase-3 activation limitation and reduction in TUNEL-positive cells staining. On the other hand, amygdala TUNEL-positive cell numbers were not reduced in the Late group. Moreover, TNFalpha was significantly reduced in the amygdala of the Early group compared to the Control and Late groups. These results indicate that A(2A) adenosine receptor stimulation is associated with apoptosis regression in the amygdala following myocardial infarction.

Developmental variation of sugars, carboxylic acids, purine alkaloids, fatty acids, and endoproteinase activity during maturation of Theobroma cacao L. seeds

The changes of mono- and oligosaccharides, carboxylic acids, purine alkaloids, and fatty acid composition, and of aspartic endoproteinase activity, were analyzed during seed development in two varieties of cacao (Theobroma cacao). The majority of the components examined either decreased or accumulated steadily in concentration during the second half of bean development. Sucrose is the major sugar in the mature embryo, whereas fructose and glucose are at higher concentrations in the endosperm tissue. Considerable amounts of malate are found in the endosperm, whereas citrate is the dominant carboxylic acid in the embryo. A major change in the fatty acid composition occurs in the young embryo when the proportion of stearic acid increases rapidly at the expense of linoleic acid, which is reduced from about 18 to 3%. Theobromine is the dominant purine alkaloid (ca. 80%), and caffeine appears only toward the end of seed maturity. Aspartic endoproteinase activity increases rapidly during embryo expansion, reaching a maximal activity before final maturity. The results are discussed in conjunction with physiological changes in developing seeds, and the potential contributions of the compounds analyzed for cocoa quality.

Pimozide (Orap) prolongs cardiac repolarization by blocking the rapid component of the delayed rectifier potassium current in native cardiac myocytes

BACKGROUND

Several cases of QT prolongation and ventricular tachyarrhythmia have been reported with pimozide, a potent neuroleptic useful in the management of motor and phonic tics associated with Tourette syndrome. To further elucidate the mechanism underlying these clinical observations, the effects of pimozide on monophasic action potential duration (MAPD(90)) and on potassium currents involved in the repolarization of native isolated ventricular myocytes were examined.

METHODS AND RESULTS

Studies were undertaken in eight isolated guinea pig hearts that demonstrated reverse rate-dependent prolongation of cardiac repolarization by pimozide 100 nmol/L. Action potential duration increased 24% from baseline 115 +/- 2 to 142 +/- 4 msec with pimozide 100 nmol/L during pacing at 250 msec cycle length, while a 10% increase from 97 +/- 2 to 107 +/- 3 msec was seen with pacing at a cycle length of 150 msec. Experiments in native isolated ventricular myocytes (n = 20) demonstrated concentration-dependent block of the rapid component (I(Kr)) of the delayed rectifier potassium current: tail current was decreased by 50% at 15 nmol/L.

CONCLUSIONS

Pimozide possesses cardiac electrophysiological effects similar to those of class III antiarrhythmic drugs. These effects are concentration-dependent and observed at recommended dosages of the drug. Since pimozide is strongly metabolized by CYP3A4, special care should be taken to avoid potential pharmacokinetic interactions leading to high plasma levels of pimozide and proarrhythmia.

Ca(2+)-dependent sensitization of adenylyl cyclase activity

It has been shown that intracellular Ca(2+) concentrations have multiple modulatory influences on hormone-stimulated adenylyl cyclase activity. Here, we report that increasing intracellular Ca(2+) concentration by treating cells with the Ca(2+) ionophore A23187 leads to a sensitization of the beta-adrenoceptor-stimulated adenylyl cyclase activity in Ltk(-) cells expressing the human beta(2)-adrenoceptor. The ionophore treatment led to a 20+/-5% increase of the maximal isoproterenol-stimulated cyclase activity that could be prevented by chelation of the extracellular Ca(2+) using EGTA. A similar Ca(2+)-mediated sensitization (20+/-6%) was observed when the adenylyl cyclase was directly stimulated by the diterpene forskolin indicating that the catalytic activity of the enzyme itself is modulated by the change in Ca(2+) concentration. Sensitization of both the isoproterenol- and forskolin-stimulated adenylyl cyclase activities were completely blocked by treatment with KN-62[1-[N,O-bis-(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine], an inhibitor of the Ca(2+)-calmodulin-dependent protein kinase (CamKinase). Taken together, our data reveal the existence of a CamKinase-dependent sensitization process acting at the level of the adenylyl cyclase catalytic moiety.

Evaluation of exo-endo ratios in the halolactonization of omega-unsaturated acids

The reaction of 2-(omega-alkenyl)benzoic acids with bis(collidine)iodine and bis(collidine)bromine hexafluorophosphate was examined. Except with 2-but-3-enylbenzoic acid, for which only the exo lactone was obtained, for the other acids a mixture of exo-endo lactones was always obtained. The proportion of endo lactone was important for the acid chain length of 11 carbons (formation of a 12-membered ring endo lactone) and for the acid chain lengths higher than 14 carbons. The formation of the endo lactones was explained, on the base of molecular calculations, by competition between electronic and steric effects. These latter were developed by transannular interactions (for the acid chain lengths 8-11) and/or the conformations adopted by the chains (for the acid chain lengths > or = 14,) which disfavored the formation of the exo lactones. The larger proportion of endo lactones observed with the bromo reagent compared to the iodo reagent seemed due to electronic factors.

Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes

To corroborate alterations in the functional responses to beta-adrenergic receptor (beta-AR) stimulation with changes in beta-AR signaling in failing cardiomyocytes, contractile and L-type Ca(2+) current responses to isoproterenol along with stimulated cAMP generation were compared among cardiomyocytes isolated from canines with tachycardia-induced heart failure or healthy hearts. The magnitude of shortening of failing cardiomyocytes was significantly depressed (by 22 +/- 4.4%) under basal conditions, and the maximal response to isoproterenol was significantly reduced (by 45 +/- 18%). Similar results were obtained when the responses in the rate of contraction and rate of relaxation to isoproterenol were considered. The L-type Ca(2+) current amplitude measured in failing cardiomyocytes under basal conditions was unchanged, but the responses to isoproterenol were significantly reduced compared with healthy cells. Isoproterenol-stimulated cAMP generation was similar in sarcolemmal membranes derived from the homogenates of failing (45 +/- 6.8) and healthy cardiomyocytes (52 +/- 8.5 pmol cAMP. mg protein(-1). min(-1)). However, stimulated cAMP generation was found to be significantly reduced when the membranes were derived from the homogenates of whole tissue (failing: 67 +/- 8.1 vs. healthy: 140 +/- 27.8 pmol cAMP. mg protein(-1). min(-1)). Total beta-AR density was not reduced in membranes derived from either whole tissue or isolated cardiomyocyte homogenates, but the beta(1)/beta(2) ratio was significantly reduced in the former (failing: 45/55 vs. healthy: 72/28) without being altered in the latter (failing: 72/28, healthy: 77/23). We thus conclude that, in tachycardia-induced heart failure, reduction in the functional responses of isolated cardiomyocytes to beta-AR stimulation may be attributed to alterations in the excitation-contraction machinery rather than to limitation of cAMP generation.

The palmitoylation state of the beta(2)-adrenergic receptor regulates the synergistic action of cyclic AMP-dependent protein kinase and beta-adrenergic receptor kinase involved in its phosphorylation and desensitization

Although palmitoylation of the beta(2)-adrenergic receptor (beta(2)AR), as well as its phosphorylation by the cyclic AMP-dependant protein kinase (PKA) and the beta-adrenergic receptor kinase (beta ARK), are known to play important roles in agonist-promoted desensitization, their relative contribution and mutual regulatory influences are still poorly understood. In this study, we investigated the role that the carboxyl tail PKA site (Ser(345,346)) of the beta(2)AR plays in its rapid agonist-promoted phosphorylation and desensitization. Mutation of this site (Ala(345,346)beta(2)AR) significantly reduced the rate and extent of the rapid desensitization promoted by sustained treatment with the agonist isoproterenol. The direct contribution of Ser(345,346) in desensitization was then studied by mutating all other putative PKA and beta ARK phosphorylation sites (Ala(261,262)beta ARK(-)beta(2)AR). We found this mutant receptor to be phosphorylated upon receptor activation but not following direct activation of PKA, suggesting a role in receptor-specific (homologous) but not heterologous phosphorylation. However, despite its phosphorylated state, Ala(261,262)beta ARK(-)beta(2)AR did not undergo rapid desensitization upon agonist treatment, indicating that phosphorylation of Ser(345,346) alone is not sufficient to promote desensitization. Taken with the observation that mutation of either Ser(345,346) or of the beta ARK phosphorylation sites prevented both the hyper-phosphorylation and constitutive desensitization of a palmitoylation-less mutant (Gly(341)beta(2)AR), our data suggest a concerted/synergistic action of the two kinases that depends on the palmitoylation state of the receptor. Consistent with this notion, in vitro phosphorylation of Gly(341)beta(2)AR by the catalytic subunit of PKA facilitated further phosphorylation of the receptor by purified beta ARK. Our study therefore allows us to propose a coordinated mechanism by which sequential depalmitoylation, and phosphorylation by PKA and beta ARK lead to the functional uncoupling and desensitization of the ss(2)AR.

Domperidone should not be considered a no-risk alternative to cisapride in the treatment of gastrointestinal motility disorders

BACKGROUND

Several cases of QT prolongation and ventricular tachyarrhythmia have been reported with domperidone, a gastrokinetic and antiemetic agent available worldwide but still under investigation in the United States. Although electrolyte disturbances such as hypokalemia could account for some of these events, we hypothesized that domperidone may have unsuspected electrophysiological effects predisposing some patients to proarrhythmia.

METHODS AND RESULTS

Studies were undertaken in 9 isolated guinea pig hearts, which demonstrated reverse use-dependent prolongation of cardiac repolarization by 100 nmol/L domperidone. Action potential duration increased 27% from baseline with domperidone (from 114+/-3 to 145+/-2 ms) during pacing at a cycle length of 250 ms, and a 9% increase (from 97+/-2 to 106+/-3 ms) was seen with pacing at a cycle length of 150 ms. Experiments in human ether-a-go-go-related gene (HERG)-transfected Chinese hamster ovary cells (n=32) demonstrated a concentration-dependent block of the rapid component (I(Kr)) of the delayed rectifier potassium current. The tail current decreased by 50% at 162 nmol/L domperidone.

CONCLUSIONS

Domperidone possesses cardiac electrophysiological effects similar to those of cisapride and class III antiarrhythmic drugs. These effects are observed at clinically relevant concentrations of the drug. Therefore, domperidone should not be considered a no-risk alternative to cisapride, a drug that was recently withdrawn from the US market.

Vitamin K modulates cardiac action potential by blocking sodium and potassium ion channels

BACKGROUND

Cardiovascular collapses, syncopes, and sudden deaths have been observed following the rapid administration of intravenous vitamin K. Our objectives were to characterize the effects of vitamin K on cardiac action potentials and to evaluate effects of vitamin K on sodium and potassium currents, namely I(Na), I(Kr), and I(Ks).

METHODS AND RESULTS

Guinea pig hearts (n = 21) were paced at a cycle length of 250 msec and exposed to vitamin K at 1.15-4.6 micromol/L (2.5-10 mg/L). Monophasic action potential duration measured at 90% repolarization (MAPD(90)) was not significantly reduced (-1.6 +/- 0.3 msec; P >.05; N.S.) at 1.15 micromol/L, but increased by 6.5 +/- 0.4 msec (P <.05) at 2.3 micromol/L. MAPD(90) was not measurable at 4.6 micromol/L, as a result of inexcitability. Patch-clamp experiments in ventricular myocytes demonstrated a approximately 50% reduction in I(Na) by 10 micromol/L vitamin K and a concentration-dependent reduction of the K(+) current elicited by short depolarizations (250 msec; I(K250)). Estimated IC(50) for I(K250), mostly representing I(Kr), was 2.3 micromol/L. Vitamin K was less potent to block the K(+) current elicited by long depolarizations (5,000 msec; I(K5000)), mostly representing I(Ks), with an estimated IC(50) over 100 micromol/L.

CONCLUSIONS

Therapeutic concentrations ( approximately 1.5 micromol/L) of intravenous vitamin K modulate cardiac action potential by blocking ionic currents involved in cardiac depolarization and repolarization.

Sildenafil (Viagra) prolongs cardiac repolarization by blocking the rapid component of the delayed rectifier potassium current

BACKGROUND-Several cases of unexpected death have been reported with sildenafil in patients predisposed to ischemic cardiac events. Although acute episodes of ischemia could account for some of these deaths, we hypothesized that sildenafil may have unsuspected electrophysiological effects predisposing some patients to proarrhythmia. METHODS AND RESULTS-Studies were undertaken in 10 isolated guinea pig hearts that demonstrated prolongation of cardiac repolarization in a reverse use-dependent manner by sildenafil 30 mcmol/L. Action potential duration increased 15% from baseline 117+/-3 to 134+/-2 ms with sildenafil during pacing at 250 ms cycle length, whereas a 6% increase from 99+/-2 to 105+/-2 ms was seen with pacing at 150 ms cycle length. Experiments in human ether-a-go-go-related gene (HERG)-transfected HEK293 cells (n=30) demonstrated concentration-dependent block of the rapid component (I(Kr)) of the delayed rectifier potassium current: activating current was 50% decreased at 100 mcmol/L. This effect was confirmed using HERG-transfected Chinese hamster ovary (CHO) cells, which exhibit no endogenous I(K)-like current. CONCLUSIONS-Sildenafil possesses direct cardiac electrophysiological effects similar to class III antiarrhythmic drugs. These effects are observed at concentrations that may be found in conditions of impaired drug elimination such as renal or hepatic insufficiency, during coadministration of another CYP3A substrate/inhibitor, or after drug overdose and offer a new potential explanation for sudden death during sildenafil treatment.

Depression's forgotten genealogy: notes towards a history of depression

The history of depression remains unwritten, yet historians harbor plentiful assumptions about its pre-1800 past. These views are necessarily colored, even shaped, by modern views of depression formed after its nineteenth-century medicalization. A history of depression from ancient to modern times is an impossible task to complete successfully and would require, as a minimum, the historian's utmost vigilance to nuance, difference, and the inclusion of non-medical literature, especially poetry, drama and non-didactic prose. Nevertheless, five points about depression's pre-1800 European profile can confidently be made: (1) it developed along lines of female rather than male gender; (2) was transformed in the long eighteenth century when it blended with male madness under the sway of the cults of a pan-European sensibility movement; (3) always embedded a problematic pseudo-depressive state, or feigned version, which acted to permit female escape from dire socio-economic situation; (4) included sustained chronic duration as a requirement in its theory from the Renaissance forward; (5) is richly documented in its pre-1800 versions in imaginative literature, its often overlooked genealogy.

Effects of calcitonin on animal and in vitro models of skeletal metabolism

During the 40 years since its discovery, calcitonin (CT) has been regarded primarily as an inhibitor of bone resorption and its therapeutic applications have been based on this property. A significant body of literature also indicates additional anabolic effects in animal and in vitro models. In a variety of bone loss histomorphometric models in the rat, CT, especially the salmon species, prevents or retards bone loss. In other species, similar results have been obtained, except in the beagle given human CT, in which a recent study reported increased bone resorption and bone loss. Consonant with the histomorphometric effects in several different species, bone mass (density) measured by a variety of methods increases, reversing the bone loss induced by the model. In related studies of mechanical properties, bone strength is increased by CT except in the beagle study which utilized human CT. In other species, experimentally induced fractures show either accelerated healing or heal normally, and there is no effect of CT to impair healing. Finally, studies of bone formation/mineralization strongly suggest an anabolic effect on cartilage formation, bone matrix synthetic activity, and bone growth. These animal effects are reflected by recent fracture prevention studies in humans. If its anabolic effects are ultimately found to be separable and additive to CT's basic action to inhibit bone resorption, new approaches to osteoporosis prevention, and possibly other treatment situations such as cartilage regeneration, may evolve using novel CT-like molecules.

[Pathology of the ureterovesical junction in neurogenic bladders in children and adolescents. A retrospective study of 119 patients]

Ureterovesical junction dysfunction in congenital or acquired neurogenic bladders represents a threat for the renal parenchyma. In order to evaluate the incidence, mechanisms of development and preventive and curative treatments proposed in diseases of the ureterovesical junction associated with neurogenic bladders, the files of 119 children were retrospectively evaluated. 68 patients suffered from congenital neurogenic bladder and 51 had an acquired neurogenic bladder. In the congenital neurogenic bladder group, vesico-ureteric reflux was observed in 22 cases (32%) and dilatation was observed in 18 cases (26.5%), while 21 patients had both dilatation and reflux. In the acquired neurogenic bladder group, reflux was observed in 8 cases (16%) and dilatation was observed in 3 cases (10%), one of whom had both reflux and dilatation. The predominant mechanism of decompensation of the ureterovesical junction in the two groups was a combination of low compliance and high peripheral resistance. In patients with abnormalities of the ureterovesical junction, the incidence of associated parenchymal lesions was similar (30%) whether neurogenic bladder was congenital or acquired. The disparities between these two comparable patient groups, the preventive and curative treatments proposed and their results are analysed in comparison with the data reported in the literature.

Determination of ubiquinone-9 and 10 levels in rat tissues and blood by high-performance liquid chromatography with ultraviolet detection

A high-performance liquid chromatographic (HPLC) method is presented for the simultaneous detection of ubiquinone-9 and 10 in rat tissues such as blood, myocardium, and muscle. After liquid-liquid extraction, the ubiquinones are subsequently analyzed by HPLC with ultraviolet (UV) detection at their maximum absorbance (275 nm). Reference calibration curves in ethanol are used to determine tissular levels of ubiquinones. Because a treatment with HMG-CoA reductase inhibitors is expected to decrease the ubiquinone levels, reference calibration curves are performed to ensure that the ratios (ubiquinone/internal standard) observed in such an experiment could be evaluated directly on a calibration curve. The assay is sensitive (0.0625 microgram/mL), reproducible (4% coefficient of variation for ubiquinone-9 and 6% for ubiquinone-10), and linear up to 20 micrograms/mL (or 100 mg of tissue) for ubiquinone-9 and up to 10 micrograms/mL (or 100 mg of tissue) for ubiquinone-10. The ubiquinone levels in control tissues or blood are within the ranges of those previously reported.

Chronic beta-blockade increases skeletal muscle beta-adrenergic-receptor density and enhances contractile force

The effects of a chronic 14-day administration of a selective beta2-adrenergic-receptor antagonist (ICI-118551) on skeletal muscle were evaluated in female Sprague-Dawley rats. Chronic ICI-118551 treatment did not modify muscle mass, oxidative potential, or protein concentration of the medial gastrocnemius muscle, suggesting that maintenance of these skeletal muscle characteristics is not dependent on beta2-adrenergic-receptor stimulation. However, the drug treatment increased beta-adrenergic-receptor density of the lateral gastrocnemius (42%) and caused an increase in specific (g/g) isometric in situ contractile forces of the medial gastrocnemius [twitch, 56%; tetanic (200 Hz), 28%]. The elevated contractile forces observed after a chronic treatment with ICI-118551 were completely abolished when the beta2-adrenergic antagonist was also administered acutely before measurement of contractile forces, suggesting that this response is beta2-adrenergic-receptor dependent. Possible mechanisms for the increased forces were studied. Caffeine administration potentiated twitch forces but had little effect on tetanic force in control animals. Administration of dibutyryl adenosine 3',5'-cyclic monophosphate in control animals also resulted in small increases of twitch force but did not modify tetanic forces. We conclude that increases in beta-adrenergic-receptor density and the stimulation of the receptors by endogenous catecholamines appear to be responsible for increased contractile forces but that the mechanism remains to be demonstrated.

Influence of receptor density on the patterns of beta2-adrenocepter desensitization

Sustained stimulation of the beta2-adrenoceptor leads to a desensitization of the receptor-mediated adenylyl cyclase stimulation. While desensitization promoted by nanomolar concentrations of isoproterenol involves the phosphorylation of the beta2-adrenoceptor by protein kinase A alone, both protein kinase A- and beta-adrenoceptor kinase-mediated phosphorylation leading to the binding of beta-arrestin contribute to the desensitization evoked by micromolar concentrations of agonist. In the present study, we assessed the influence of receptor density on the patterns of desensitization induced by these two different levels of stimulation. Murine L cells were transfected with a cDNA encoding the human beta2-adrenoceptor and clonal cell lines expressing various levels of beta2-adrenoceptor were used for the study. In cell lines expressing the highest number of receptor, approx. 150000 sites/cell (approx. 3000 fmol/mg of membrane proteins), pretreatment with micromolar concentrations of isoproterenol causes a desensitization pattern characterized by a reduction in both the potency and the efficacy of isoproterenol to further stimulate the adenylyl cyclase activity. In contrast, desensitization induced by 10 nM isoproterenol resulted only in a decrease in the potency of isoproterenol. This distinct pattern of desensitization is not seen in cells expressing 12000 receptors/cell (approx. 200 fmol/mg of membrane proteins) and, in that case, pretreatment with 10 nM isoproterenol leads to a reduction in both the sensitivity and the maximal response. Similar effects on the beta-adrenoceptor-stimulated adenylyl cyclase were observed in these cells following treatment with dibutyryl cAMP. Receptor density therefore dramatically influences the pattern of desensitization evoked by low level of stimulation. The results also demonstrate that although different molecular events are involved in the desensitization evoked by different levels of stimulation, its phenotypic expression can be qualitatively identical in cells expressing a relatively small number of receptors. Hence, protein kinase A-mediated desensitization cannot be qualitatively distinguished from the beta-adrenoceptor kinase-mediated process in these cells.

Improvement of the lateral-mode discrimination of broad-area diode lasers with a profiled reflectivity output facet

The emission of a broad-area laser always contains several lateral modes (along the junction plane) even at low drive levels. To increase the discrimination against high-order lateral modes, we developed simple techniques for depositing a profiled thin layer of SiO on the output facet of a broad-area laser that has a 75-μm-wide injection current stripe. The profiled coating provided a nearly Gaussian reflectivity in the lateral direction (parallel to the junction plane). The resolved near-field spectra of the uncoated and coated lasers have been compared. The maximum output power in the single-lateral-mode regime was pushed to 25 mW with the profiled coating, compared with a corresponding power of less than 1 mW before deposition. Experimental results have confirmed the behavior predicted by our numerical simulations. This method is scalable to higher-power lasers.

Distinct receptor domains determine subtype-specific coupling and desensitization phenotypes for human beta1- and beta2-adrenergic receptors

Human beta1- and beta2-adrenergic receptor (beta1 AR and beta2 AR) coupling and desensitization characteristics were compared in defined heterologous expression systems. Significant differences in the coupling efficacies of the two subtypes were found in both Chinese hamster fibroblasts and murine Ltk- fibroblasts, which were used as surrogate cell lines. At the maximal level of stimulation with the nonselective beta-adrenergic agonist isoproterenol, beta1 AR-mediated adenylyl cyclase activation represented 70% and 20% of that mediated by beta2 AR in Chinese hamster and murine Ltk- fibroblasts, respectively. Sustained (15 min) stimulation with subsaturating concentration of isoproterenol (< 10% of receptor occupancy) led to identical desensitization of the beta-adrenergic-stimulated adenylyl cyclase activity for both beta1 AR and beta2AR-expressing cells. In contrast, when a nearly saturating concentration of isoproterenol (> 90% of receptor occupancy) was used to promote desensitization, the extent of desensitization observed for beta2 AR-expressing cells was 1.7-2-fold higher than that of the beta1 AR. The carboxyl domain of several G protein-coupled receptors has been shown to play important roles in both coupling efficacy and agonist-promoted desensitization. Therefore, we examined the contribution of this receptor domain in the subtype-selective phenotypes described above. A chimeric receptor composed of the first six transmembrane domains of the beta1 AR and of the seventh transmembrane domain and carboxyl tail of the beta2 AR maintained a coupling efficacy characteristic of the beta1 AR, whereas the extent of desensitization resulting from high receptor occupancy was identical to that of the beta2 AR. These results therefore suggest that the carboxyl portion of the beta1 AR and beta2 AR determines their subtype-selective desensitization patterns but not their respective coupling efficacies.

Clentiazem given at reperfusion improves subendocardial reflow and reduces myocardial infarct size in the dog

The postischemic cardioprotection by calcium antagonists and the interplay between neutrophils and regional myocardial blood flow were investigated further, using clentiazem, a new potent calcium channel blocker derived from diltiazem. A 90-min occlusion of the interventricular coronary artery was followed by 6 hr of reperfusion in anesthetized dogs. One group was given clentiazem: 100 micrograms/kg at 5 min before reperfusion followed by a perfusion of 1 microgram/kg/min until sacrifice; controls received saline. Infarct size (% of area at risk) estimated with triphenyltetrazolium staining and by histology was reduced by nearly 50% (P < .05) in treated (16.6 +/- 3.0%), as compared to control (31.6 +/- 6.3%) dogs. Regional and collateral myocardial flows estimated with radioactive microspheres were similar between groups before and during occlusion. However, after an initial recovery to preocclusion values at 30-min reperfusion in both groups, flow declined to 50% normal (P < .05) in control animals after 3 and 6 hr in midwall and subendocardium, but the change was remarkably attenuated (P < .05) in subendocardium of clentiazem-treated dogs. Also, neutrophil accumulation at the epicardial side of the infarct, at the edge of salvaged myocardium, and estimated by tissue myeloperoxidase measurement, was reduced by 50% in treated dogs (clentiazem: 17.2 +/- 2.8; controls: 32.3 +/- 2.7 x 10(6) neutrophils/g). We conclude that administration of clentiazem at reperfusion reduces infarct size by interfering with both neutrophil accumulation and development of subendocardial no reflow in reperfused myocardium.