Role of emotional processing in depressive responses to sex-hormone manipulation: a pharmacological fMRI study.

Sex-hormone fluctuations may increase risk for developing depressive symptoms and alter emotional processing as supported by observations in menopausal and pre- to postpartum transition. In this double-blinded, placebo-controlled study, we used blood-oxygen level dependent functional magnetic resonance imaging (fMRI) to investigate if sex-steroid hormone manipulation with a gonadotropin-releasing hormone agonist (GnRHa) influences emotional processing. Fifty-six healthy women were investigated twice: at baseline (follicular phase of menstrual cycle) and 16 ± 3 days post intervention. At both sessions, fMRI-scans during exposure to faces expressing fear, anger, happiness or no emotion, depressive symptom scores and estradiol levels were acquired. The fMRI analyses focused on regions of interest for emotional processing. As expected, GnRHa initially increased and subsequently reduced estradiol to menopausal levels, which was accompanied by an increase in subclinical depressive symptoms relative to placebo. Women who displayed larger GnRHa-induced increase in depressive symptoms had a larger increase in both negative and positive emotion-elicited activity in the anterior insula. When considering the post-GnRHa scan only, depressive responses were associated with emotion-elicited activity in the anterior insula and amygdala. The effect on regional activity in anterior insula was not associated with the estradiol net decline, only by the GnRHa-induced changes in mood. Our data implicate enhanced insula recruitment during emotional processing in the emergence of depressive symptoms following sex-hormone fluctuations. This may correspond to the emotional hypersensitivity frequently experienced by women postpartum.

What is the best hydration regimen to prevent contrast media-induced nephrotoxicity?

BACKGROUND: Hydration is a commonly used method to prevent the decline in GFR after contrast media (CM) application. So far, there have been no controlled, randomized trials investigating the most effective route of fluid administration. METHODS: Thirty-nine patients with normal renal function (65 +/- 9 years, serum creatinine 0.9 +/- 0.2 mg/dl, GFR = 110 +/- 31 ml/min/1.73 m2) receiving at least 80 ml of low-osmolality CM during an angiographic procedure were randomized to one of the following hydration regimens: Group 1: volume expansion with 300 ml saline during CM administration (n = 20, serum creatinine 0.8 +/- 0.1 mg/dl, GFR 119 +/- 27 ml/min/1.73 m2); Group 2: intravenous administration of at least 2,000 ml saline within 12 h before and after CM application (n = 19, serum creatinine 0.9 +/- 0.2 mg/dl, GFR 101 +/- 32 ml/min/1.73 m2). GFR was measured by CM clearance (Renalyzer) at baseline and 48 hours after CM administration. The primary end point was the mean change in the GFR after 48 hours, the secondary one was the incidence of CM-induced nephropathy (CMIN), defined as a decrease in GFR of more than 50% from the baseline GFR within 48 hours. RESULTS: Patients of group 1 showed a significantly (p < 0.05) higher decline in GFR (delta GFR 34.6 +/- 25.7 ml/min/1.73 m2) compared to patients receiving the intravenous prehydration regimen (delta GFR 18.3 +/- 25.0 ml/min/1.73 m2). The incidence of CMIN was lower in prehydrated patients (5.3%) compared to the other group (15%). CONCLUSION: In patients with normal renal function, intravenous prehydration seems to be a very effective and feasible method to prevent the decline in GFR after contrast media exposure. Volume expansion given only during the CM exposure appears not to be sufficient enough to prevent renal damage.

Het gebruik van chemische oorlogsagentia: historiek en toxicologische aspecten. / [The use of chemical warfare agents: historical view and toxicological aspects]

The first wholesale use of chemical warfare agents took place in World War I. These agents can be classified either as "weapons", like choking agents, nose agents, vesicants and nerve agents, or as "expedients", like smoking agents and defoliants, depending on the fact if they are used with the purpose either to kill or to incapacitate the enemy or to interfere with his fighting performances, or if they are only applied in view of an easier enforcement of certain military operations. In this paper the history of chemical warfare will be expounded concisely, starting from the period of the "Great War" (1914-1918) up to the more recent conflicts like the first and the second Gulf War. The chemical agents used and their toxicological effects in case of exposure are also outlined briefly. As concluding remarks some particular problems, related to the possible impact of chemical weapons on the environment and on human health, that will continue to exist in the future, and this in spite of the new Chemical Weapons Convention that came into force very recently, will be pointed out.

Postsynaptic neuromuscular dysfunction in organophosphate induced intermediate syndrome.

A 65-year-old Caucasian female developed an intermediate syndrome seven days after an acute cholinergic crisis, caused by the ingestion of fenthion. Cholinesterase activity in the blood, plasma and red cells was monitored daily by the method according to Nenner and serial serum fenthion levels were measured by capillary gas chromatography. Electromyographic studies showed fade on tetanic stimulation by means of surface electrodes at 20 Hz of the left M. abductor digiti quinti at day 7, which could no longer be observed at day 19. Fade on low-frequency stimulation and post-tetanic facilitation were both absent. A biopsy of the N. suralis was normal. A biopsy of the M. tibialis anterior revealed a limited rhabdomyolysis with a very weak staining for cholinesterase. It is hypothesized that the pathophysiologic process underlying the syndrome is the result of a time-confined phenomenon, which includes both changes in the postsynaptic structures by a desensitization process and a gradually restoring ratio of acetylcholine to acetylcholinesterase. This hypothesis is suggested by the similarity in the EMG-findings of this patient and those in myasthenia gravis, which is known to be characterized by a postsynaptic transmission defect.

Saliva concentrations of disopyramide cannot substitute the drug's plasma concentrations.

For many drugs the salivary concentration corresponds to the free plasma drug concentration, which may be more closely related to drug activity or toxicity than the total plasma drug concentration. In this study a preliminary investigation was undertaken to determine the feasibility of monitoring saliva levels of disopyramide, an antiarrhythmic drug, for clinical and toxicological purposes. Single oral doses of this compound were administered to healthy volunteers. Stimulated mixed saliva and plasma levels were measured by the EMIT technique. The concentrations of disopyramide in the stimulated mixed saliva tended to be lower than those found in the corresponding plasma sample (fp 0.3-0.5), and the saliva-to-plasma concentration ratio increased with a decreasing salivary pH (pH 6.89, S/P = 0.25; pH 8.15, S/P = 0.08). The correlation between the saliva and the total plasma concentrations was significant but relatively poor, however. Consequently, mixed salivary disopyramide concentrations are a poor indicator of plasma concentrations, even if correction is made for pH change.

Disposition of tilidine in a fatal poisoning in man.

A fatal intoxication due to the ingestion of tilidine, a narcotic analgesic, in conjunction with ethanol, is described. Tilidine and its two active metabolites, nortilidine and bisnortilidine, were identified and quantitated in the biological fluids and tissues by thin-layer chromatography (TLC), gas-liquid chromatography with sensitive nitrogen-phosphorus detection (GLC/NPD) and gas-liquid chromatography with mass spectrometric detection (GC/MS). The toxicological results are compared with previously reported 14C-tilidine tissue distributions in rats following oral administration and limited tissue data in a previously reported human fatality. In the present case, the death was attributed to the combined central nervous system-depressing effects of ethanol and tilidine.

In vitro adsorption of tilidine HCl by activated charcoal.

In vitro studies were carried out in order to determine the adsorption of tilidine HCl, a narcotic analgesic, by activated charcoal (max. adsorption capacity 185.5 mg/g of charcoal). The path of the adsorption isotherms at pH 1.2 and 7.5 suggests that the in vivo adsorption of tilidine HCl may be increased when the drug passes from the stomach to the intestine, unless the intestinal content exerts a displacing effect. Nevertheless, the adsorption was dependent on the quantity of activated charcoal used, becoming more complete when the quantity of activated charcoal was increased. The effects of additives on the adsorption capacity of activated charcoal were also investigated in vitro. Ethanol, sorbitol and sucrose significantly reduced drug adsorption, while cacao powder, milk and starch had no effect on tilidine adsorption. At an acid pH, Federa Activated Charcoal significantly adsorbed more drug than either Norit A or Activated Charcoal Merck.

Combined use of fused silica capillary columns and nitrogen-phosphorus detection for the toxicological analysis of illicit heroin samples.

Capillary GC is applied to the toxicological analysis of illicit heroin samples. The combined use of a permanently deactivated fused silica capillary column, and a nitrogen-phosphorus detector (NPD), allows the separation and determination of nanogram amounts of underivatised opiates, using a direct injection technique.

A double fatality with children due to fumigated wheat.

Two children, four and two years old, played on top of wheat, that had been fumigated with malathion, pyrethrum and phosphine. Both died within 18 hours. Because after the autopsy, death could not be attributed to any organic or violent cause, a toxicological analysis was carried out. No drugs, except alcohol, was detected. Those results were attributed to hydrolysis of malathion, yielding two molecules of ethanol. As this was an indirect proof of malathion ingestion, it was assumed that phosphine had been ingested as well and that consequently this was the cause of death, because it is much more toxic than malathion and because it was continuously generated from not completely dissolved aluminiumphosphide tablets, while the children were still playing.