Olestra increases faecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin

Two patients with chloracne had concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of 144,000 and 26,000 pg/g blood lipids. Olestra, a non-digestible, lipophilic dietary fat substitute accelerated the patients' intestinal excretion of TCDD by eight to ten fold. This is sufficient to reduce the normally observed elimination half life of TCDD from about 7 years to 1-2 years.

[MRI characteristics of spontaneous intracerebral hemorrhage]

We review the signal characteristics of intracerebral hematomas (ICH) on magnetic resonance imaging (MRI), with special emphasis on the diagnosis of intracerebral hemorrhage within the first hours after stroke.The detection of peracute ICH was evaluated in 42 patients of a prospective, MR randomized stroke trial. These patients underwent a protocol of T1 and T2 weighted sequences, diffusion weighted sequences and MR - angiography within 6 hours after onset of acute hemiparesis. The signal behaviour of ICH in any stage after bleeding was additionally reviewed in a retrospective series of 63 patients, who were submitted for MRI over a 12 months period because of known ICH.MRI correctly identified 4 hyperacute ICH in the prospective group and 4 hyperacute ICH in the retrospective group. These ICHs had high signal on T2 weighted images, were isointense in T1 weighted images and had signal voids on the diffusion weighted sequences. The signal intensities of acute, subacute and chronic ICHs correlated to previous experiences as reported in the literature.In conclusion, MRI reliably identified all hematomas even in the hyperacute stage. Diffusion weighted images were most sensitive to the presence of deoxyhemoglobine and helpful for the differentiation and characterization of acute ischemia. Therefore, MRI at 1.5 T can be employed as an alternative to CT for the emergency diagnosis of acute stroke.

[Physical arrangement of membrane lipids susceptible to being used in the process of cell sorting of proteins]

Detection of immiscible lipid domains in biological membranes offers an alternative support to protein sorting. Liquid ordered domains ("rafts") comprising cholesterol and saturated sphingolipids incorporate saturated glycosyl-phosphatidylinositol (GPI)-anchored or acylated (palmitoyl- and myristoyl-) proteins or particular transmembrane protein sequences. These lipid domains can be isolated in the form of Detergent resistant membranes (DRM) from biological plasma membrane preparations. Caveolae appear to be a differentiated fraction of plasma membranes comprising such numerous cross-linked microdomains associated with caveolin in different cell types. While the biological relevance of such membrane domains is evidenced in vivo by co-patching of proteins sharing the identical affinity for sphingolipids and by the disruption of co-patching following cell cholesterol depletion, only a few physical studies confort the principle of membrane heterogeneity. Results are now presented where cholesterol addition in a tertiary lipid mixture forces outphase-separation, as a realistic model where the lipid segregation can promote protein sorting to the segregated Lo phase. A lipid mixture comprising phosphatidylserine, phosphatidylethanolamine and sphingomyelin of natural origin in the ratio (1/4/3: mole/mole) has been rendered neatly heterogeneous after the addition of cholesterol (27 mole%). Xray diffraction (Small angle Xray scattering) showed the splitting of two neatly resolved lamellar diffractions in the presence of cholesterol. Above 37 degrees C the heterogeneity was traceable by a broadened diffraction spot up to the complete get-to-liquid transition of sphingomyelin at temperatures > 40 degrees C where the spot became again symmetrical and narrow. The large temperature range where the immiscible lamellar phases are detected, the specific requirement for cholesterol association with sphingomyelin, the positive influence of calcium and the reversibility of domain formation support the occurrence for such domains at the inner side of the plasma membrane whereon lipids-bound proteins concentrate.

Columnar lined oesophagus and intestinal metaplasia: current concepts

Barrett's oesophagus is a condition where the distal oesophagus is lined with columnar epithelium. For the diagnosis intestinal metaplasia has to be found and a minimal length of 3 cm is required for the columnar-lined segment. It is well known that patients with the traditional Barrett's oesophagus have a higher risk of developing adenocarcinomas in the metaplastic segment. The clinical significance of shorter metaplastic segments and intestinal metaplasia at the gastro-oesophageal junction is much less certain. Different definitions are in use and the increasing number of studies dealing with these mucosal changes therefore may create confusion. In this article, the current knowledge concerning epidemiology, pathophysiology, clinical associations, diagnostic possibilities including endoscopy, pathology, measurement of differences in electrical potential, and treatment of columnar-lined oesophagus of any length and of intestinal metaplasia at the gastro-oesophageal junction is reviewed. Furthermore, the need for a consistent definition is emphasized.

Synthesis and in vitro multidrug resistance modulating activity of a series of dihydrobenzopyrans and tetrahydroquinolines

A series of dihydrobenzopyrans and tetrahydroquinolines was synthesized and pharmacologically tested for their ability to inhibit P-glycoprotein mediated daunomycin efflux in multidrug resistant CCRF-CEM vcr1000 cells. Several compounds exhibit activities in the range of the reference compounds verapamil and propafenone. Preliminary structure-activity relationship studies propose the importance of high molar refractivity values of the compounds and the presence of an additional basic nitrogen atom.

PCR-RFLP analysis of mitochondrial DNA: a reliable method for species identification

A method for identification of game species has been developed on the basis of the amplification of a specific part of the mitochondrial genome (tRNA(Glu)/cytochrome b) using the polymerase chain reaction (PCR). To distinguish between several game species, the obtained 464-bp-long PCR products were cut with different restriction endonucleases (RE) resulting in species-specific restriction fragment length polymorphism (RFLP). Even closely related deer species could be distinguished by application of one or two RE. Natural polymorphisms of the target sequence within one species were examined for red deer (Cervus elaphus), and base pair substitutions were identified affecting the RFLP pattern.

Oxidized derivatives of 7-dehydrocholesterol induce growth retardation in cultured rat embryos: a model for antenatal growth retardation in the Smith-Lemli-Opitz syndrome

7-Dehydrocholesterol accumulates in fetuses affected by the Smith-Lemli-Opitz syndrome as a result of a deficit in the ultimate step of cholesterol synthesis catalyzed by Delta7 reductase. Rat embryos explanted at gestation day 10 and cultured for 48 h in the presence of the Delta7 reductase inhibitor AY 9944 were used as a model to discriminate between the beneficial effect of supplementation with cholesterol and the deleterious effect of supplementation with 7-dehydrocholesterol. Cholesterol supplementation in the form of mixed cholesterol/lecithin liposomes added to serum serving as the culture medium restores the growth of embryos which is markedly decreased in the presence of the inhibitor. 7-Dehydrocholesterol under identical conditions does not restore growth and impairs the beneficial effect of cholesterol added simultaneously. UV-photooxidation of 7-dehydrocholesterol-supplemented culture medium enhances its embryotoxicity, which suggests uptake by the embryo of toxic by-products formed from 7-dehydrocholesterol. By contrast photooxidation of cholesterol-supplemented culture medium does not induce embryotoxicity. alpha-Tocopherol reduces the toxicity of photooxidized 7-dehydrocholesterol supplementing the culture medium. We conclude that 7-dehydrocholesterol does not fulfill the cholesterol requirement of the developing embryos and exerts an additional embryotoxic effect probably via oxidized by-products. This could explain the antenatal growth retardation of SLOS by a blockage of the maternal compensatory cholesterol influx.

Administration of potentially antiandrogenic pesticides (procymidone, linuron, iprodione, chlozolinate, p,p'-DDE, and ketoconazole) and toxic substances (dibutyl- and diethylhexyl phthalate, PCB 169, and ethane dimethane sulphonate) during sexual differentiation produces diverse profiles of reproductive malformations in the male rat

Antiandrogenic chemicals alter sexual differentiation by a variety of mechanisms, and as a consequence, they induce different profiles of effects. For example, in utero treatment with the androgen receptor (AR) antagonist, flutamide, produces ventral prostate agenesis and testicular nondescent, while in contrast, finasteride, an inhibitor of 5 alpha-dihydrotestosterone (DHT) synthesis, rarely, if ever, induces such malformations. In this regard, it was recently proposed that dibutyl phthalate (DBP) alters reproductive development by a different mechanism of action than flutamide or vinclozolin (V), which are AR antagonists, because the male offsprings display an unusually high incidence of testicular and epididymal alterations--effects rarely seen after in utero flutamide or V treatment. In this study, we present original data describing the reproductive effects of 10 known or suspected anti-androgens, including a Leydig cell toxicant ethane dimethane sulphonate (EDS, 50 mg kg-1 day-1), linuron (L, 100 mg kg-1 day-1), p,p'-DDE (100 mg kg-1 day-1), ketoconazole (12-50 mg kg-1 day-1), procymidone (P, 100 mg kg-1 day-1), chlozolinate (100 mg kg-1 day-1), iprodione (100 mg kg-1 day-1), DBP (500 mg kg-1 day-1), diethylhexyl phthalate (DEHP, 750 mg kg-1 day-1), and polychlorinated biphenyl (PCB) congener no. 169 (single dose of 1.8 mg kg-1). Our analysis indicates that the chemicals discussed here can be clustered into three or four separate groups, based on the resulting profiles of reproductive effects. Vinclozolin, P, and DDE, known AR ligands, produce similar profiles of toxicity. However, p,p'-DDE is less potent in this regard. DBP and DEHP produce a profile distinct from the above AR ligands. Male offsprings display a higher incidence of epididymal and testicular lesions than generally seen with flutamide, P, or V even at high dosage levels. Linuron treatment induced a level of external effects consistent with its low affinity for AR [reduced anogenital distance (AGD), retained nipples, and a low incidence of hypospadias]. However, L treatment also induced an unanticipated degree of malformed epididymides and testis atrophy. In fact, the profile of effects induced by L was similar to that seen with DBP. These results suggest that L may display several mechanisms of endocrine toxicity, one of which involves AR binding. Chlozolinate and iprodione did not produce any signs of maternal or fetal endocrine toxicity at 100 mg kg-1 day-1. EDS produced severe maternal toxicity and a 45% reduction in size at birth, which resulted in the death of all neonates by 5 days of age. However, EDS only reduced AGD in male pups by 15%. Ketoconazole did not demasculinize or feminize males but rather displayed anti-hormonal activities, apparently by inhibiting ovarian hormone synthesis, which resulted in delayed delivery and whole litter loss. In summary, the above in vivo data suggest that the chemicals we studied alter male sexual differentiation via different mechanisms. The anti-androgens V, P, and p,p'-DDE produce flutamide-like profiles that are distinct from those seen with DBP, DEHP, and L. The effects of PCB 169 bear little resemblance to those of any known anti-androgen. Only in depth in vitro studies will reveal the degree to which one can rely upon in vivo studies, like those presented here, to predict the cellular and molecular mechanisms of developmental toxicity.

Pitfalls in prenatal diagnosis of DMD due to placental mosaicism of the X-chromosomes: prenatal and postnatal findings in a fetus with a deletion of exons 67-71 of the dystrophin gene

Prenatal diagnosis of Duchenne and Becker muscular dystrophy (DMD) is performed as a routine procedure in many laboratories. The major potential problem is an incorrect diagnosis that could be obtained due to contamination with maternal tissue. We report a case of mosaicism of the X-chromosomes confined to the placenta as a possible source of confusing results in prenatal diagnosis of DMD. To the best of our knowledge, this is the first reported case of this problem in a prenatal DMD diagnosis.

Cholesterol relieves the inhibitory effect of sphingomyelin on type II secretory phospholipase A2

Secretory type II phospholipase A2 (sPLA2) is inhibited by sphingomyelin (SPH); cholesterol either mixed with the model glycerophospholipid substrate or added to the assay medium as separated liposomes counteracts this inhibition efficiently. The inhibition of fatty acid release assayed by quantitative gas chromatography-MS is observed when SPH is added to erythrocyte membranes as the substrate instead of a readily hydrolysable phosphatidylethanolamine/phosphatidylserine model mixture. Hydrolysis of SPH by Staphylococcus aureus sphingomyelinase suppresses its inhibitory potency. The addition of cholesterol to SPH liposomes with a 1:1 stoichiometry relieves completely the inhibition of sPLA2 exerted by SPH. The mechanism of inhibition suggested by the binding assay is that sPLA2 binds with affinity to the SPH interface, after either phase segregation at the assay temperature or on the pure SPH liposomes added to the incubation medium. Cholesterol is shown to suppress the binding affinity of the enzyme for the SPH interface. A model for inhibition is suggested in which binding of the sphingosine moiety is competitive for sPLA2 (inhibition) or for cholesterol (release of the enzyme).

Results of two European interlaboratory studies for the determination of beta-agonists in various matrices

Two Beta-Agonist Interlaboratory Studies, 5/96 and 11/97, were designed and evaluated according to the International Harmonised Protocol for the Proficiency Testing of (Chemical) Analytical Laboratories (ISO/REMCO N 280) jointly elaborated by ISO, IUPAC and AOAC. In the sense of proficiency testing, interlaboratory studies are part of external quality assurance systems. The Beta-Agonist Interlaboratory Studies 5/96 and 11/97 were intended to offer laboratories in the EU Member States an opportunity to check objectively their routine methods for the detection of beta-agonists and to demonstrate the reliability of their analytical results; 48 and 44 laboratories, respectively, all involved in official residue control, participated in the studies. Irrespective of the large number of satisfactory results achieved at higher concentration levels according to the z-score evaluation, the number of false negative results is still unsatisfactory. The results of both Beta-Agonist Interlaboratory Studies confirmed that comparability of analytical results is not yet ensured within the European residue control system.

Secretoneurin in carcinoids of the appendix-immunohistochemical comparison with chromogranins A,B and secretogranin II

BACKGROUND

The aim of the present study was to investigate immunohistochemically the distribution of secretoneurin, a novel 33 amino acid peptide, in comparison to chromogranin A, chromogranin B, and secretogranin II in carcinoids of the appendix.

MATERIALS AND METHODS

Paraffin-embedded tissues from 47 carcinoids were incubated with antibodies specific for chromogranin A, chromogranin B, the secretogranin II derived peptide LF- 19, and secretoneurin.

RESULTS

44 tumors (94%) were positive for secretoneurin, whereas only 39 tumors (83%) were immunoreactive for chromogranin A. There was no significant correlation between neuropeptide expression and type of carcinoid, tumor size, vascular infiltration, serosal involvement or mesoappendiceal infiltration.

CONCLUSIONS

Our investigations revealed that secretoneurin is detected more frequently than chromogranin A in carcinoids of the appendix. This supports the theory that tumor cells of appendiceal carcinoids are of a different origin than other midgut carcinoids. No special tumor entity with a characteristic secretoneurin-chromogranin pattern could be identified.

[Adjuvant whole body acupuncture in depression. A placebo-controlled study with standardized mianserin therapy]

In order to examine the efficacy of whole body acupuncture additionally applied to drug treatment in depression, a single-blind placebo-controlled study with 70 inpatients administered to three different treatment groups has been carried out. All patients were pharmacologically treated with the tetracyclic antidepressant mianserin. The verum group (n = 22) received acupuncture at specific points considered to be effective in the treatment of depression. The placebo group (n = 24) was treated with acupuncture at non-specific locations and the control group (n = 24) received only pharmacological treatment. Acupuncture was applied three times a week over a period of four weeks. Psychopathology was rated by judges blind to verum/placebo conditions twice a week over eight weeks with the CGI, GAS, BRMS and BfS rating scales. Additionally applied acupuncture improved the course of depression more than pharmacological treatment with mianserin did by itself. However, we could not detect any differences between placebo and verum acupuncture.

Vascular remodeling and altered protein expression during growth of coronary collateral arteries

The cellular mechanism of growth of coronary collateral vessels (adaptive arteriogenesis) is still poorly understood. To define a possible role of an altered expression pattern of cellular and matrix proteins in this process we implanted a constricting device around the left circumflex artery in 25 canine hearts and sacrificed the animals at the time of initiation (3 weeks), high activity (6 weeks) and discontinuation (8 weeks) of vessel growth. Methods were electron microscopy, labeling with Ki-67, the TUNEL method and immunofluorescence with confocal laser microscopy. As described earlier, the collateral vessels increased in wall thickness by the formation of a neointima without luminal narrowing. We report here for the first time that extensive vascular remodeling including migration, proliferation and apoptosis in all cell types takes place during the growth phase but not in more mature vessels. The most obvious difference with normal vessels is the reiteration of an embryonal expression pattern in smooth muscle cells of the neointima which includes a significant reduction of desmin and alpha-smooth muscle actin, calponin and vinculin. Fibronectin as a promoter of migration and adhesion was abundant, its antagonist tenascin and chondroitin sulfate showed patchy localization. A completely new finding in arteriogenesis is the involvement of mast cells releasing histamine and serotonin and probably cytokines. Vascular protein expression returned to almost normal at 8 weeks indicating cessation of remodeling. We conclude that in collateral vessel development an altered cellular and matrix protein expression is involved in a drastic case of positive vascular remodeling finally resulting in mature vessels 20-fold increased in size which are capable of maintaining the functional and structural integrity of the myocardium at risk.

Characterization of a 190-kilobase pair domain of human type I hair keratin genes

Polymerase chain reaction-based screening of an arrayed human P1 artificial chromosome (PAC) library using primer pairs specific for the human type I hair keratins hHa3-II or hHa6, led to the isolation of two PAC clones, which covered 190 kilobase pairs (kbp) of genomic DNA and contained nine human type I hair keratin genes, one transcribed hair keratin pseudogene, as well as one orphan exon. The hair keratin genes are 4-7 kbp in size, exhibit intergenic distances of 5-8 kbp, and display the same direction of transcription. With one exception, all hair keratin genes are organized into 7 exons and 6 positionally conserved introns. On the basis of sequence homologies, the genes can be grouped into three subclusters of tandemly arranged genes. One subcluster harbors the highly related genes hHa1, hHa3-I, hHa3-II, and hHa4. A second subcluster of highly related genes comprises the novel genes hHa7 and hHa8, as well as pseudogene PsihHaA, while the structurally less related genes hHa6, hHa5, and hHa2 are constituents of the third subcluster. As shown by reverse transcription-polymerase chain reaction, all hair keratin genes, including the pseudogene, are expressed in the human hair follicle. The transcribed pseudogene PsihHaA contains a premature stop codon in exon 4 and exhibits aberrant pre-mRNA splicing. Evolutionary tree construction reveals an early divergence of hair keratin genes from cytokeratin genes, followed by the segregation of the genes into the three subclusters. We suspect that the 190-kbp domain contains the entire complement of human type I hair keratin genes.

Oral taurine supplementation modulates ethanol-conditioned stimulus preference

The present study investigated the possible modulatory action of oral taurine supplementation on the rewarding and aversive properties of low and high ethanol doses in male Wistar rats. A vinegar odor stimulus was daily paired with either ethanol (0.3 or 2.0 g/kg) or saline. In addition, half of the rats were supplemented orally with taurine (0.5 g/kg/day). After eight conditioning sessions, all rats were tested for their vinegar stimulus preference or aversion. In nontaurine-treated rats, 2.0 g/kg ethanol conditioning induced a significant aversion for the vinegar stimulus, while there was no preference after 0.3 g/kg ethanol conditioning. However, in taurine-supplemented rats, the 2.0 g/kg ethanol-induced aversion for the stimulus was decreased significantly, while the rats administered the lower ethanol doses, 0.3 g/kg, in combination with taurine supplementation, demonstrated a significant stimulus preference. Such results suggest that taurine modulates some of the aversive or rewarding effects of ethanol.

Generation of lyso-phospholipids from surfactant in acute lung injury is mediated by type-II phospholipase A2 and inhibited by a direct surfactant protein A-phospholipase A2 protein interaction

Lyso-phospholipids exert a major injurious effect on lung cell membranes during Acute Respiratory Distress Syndrome (ARDS), but the mechanisms leading to their in vivo generation are still unknown. Intratracheal administration of LPS to guinea pigs induced the secretion of type II secretory phospholipase A2 (sPLA2-II) accompanied by a marked increase in fatty acid and lyso-phosphatidylcholine (lyso-PC) levels in the bronchoalveolar lavage fluid (BALF). Administration of LY311727, a specific sPLA2-II inhibitor, reduced by 60% the mass of free fatty acid and lyso-PC content in BALF. Gas chromatography/mass spectrometry analysis revealed that palmitic acid and palmitoyl-2-lyso-PC were the predominant lipid derivatives released in BALF. A similar pattern was observed after the intratracheal administration of recombinant guinea pig (r-GP) sPLA2-II and was accompanied by a 50-60% loss of surfactant phospholipid content, suggesting that surfactant is a major lung target of sPLA2-II. In confirmation, r-GP sPLA2-II was able to hydrolyze surfactant phospholipids in vitro. This hydrolysis was inhibited by surfactant protein A (SP-A) through a direct and selective protein-protein interaction between SP-A and sPLA2-II. Hence, our study reports an in vivo direct causal relationship between sPLA2-II and early surfactant degradation and a new process of regulation for sPLA2-II activity. Anti-sPLA2-II strategy may represent a novel therapeutic approach in lung injury, such as ARDS.

["Multiple chemical sensitivity syndrome"]

Multiple chemical sensitivity (MCS) has been described as an acquired multiple organ disease typically characterized by central nervous irritative and/or gastrointestinal symptoms. Advocates of this suspected syndrome attribute these disorders to overstressing of the organism caused by exposure to external noxae. Opponents of the theory of MCS attribute all the symptoms to classical conditioning or other psychopathological processes. In so far as controlled data exist, there is no indication of a toxic or immunological cause for this syndrome.

Combined histamine H1/H2 receptor antagonists: part II. Pharmacological hybrids with pheniramine- and tiotidine-like substructures

Hybrid molecules combining the crucial structural features of both pheniramine-type histamine H1 receptor antagonists and guanidinothiazole-type H2 receptor antagonists have been synthesized and tested for in vitro pharmacological activity at the isolated ileum and the spontaneously beating right atrium of the guinea-pig. In the title compounds the basic side chain nitrogen of the H1 antagonist and the so-called 'polar group' (cyanoguanidine, urea, or nitroethenediamine) of the H2 antagonist moiety have been linked by a polymethylene spacer. The new substances displayed high affinities to both histamine receptor subtypes and a dual type of antagonism (surmountable/insurmountable) characterized by a shift of the concentration response curves to the right accompanied by a depression of the maximal response to the agonist if the antagonist concentration was >/=100 nM. Highest combined histamine antagonist activities were found in the nitroethenediamine series with pKB values ranging from 8.16 to 9.04 in the ileum (H1) and 7.0-8.08 in the atrium (H2)

Effect of presentation rate on word list learning in patients with dementia of the Alzheimer type

The efficacy of simple interventions for the improvement of memory performance in patients with dementia of Alzheimer type (DAT) has rarely been evaluated. Therefore, we examined the effects of presentation duration and task practice on word list learning in this sample: 19 patients with DAT and 21 control subjects (with remitted major depression) repeatedly performed modifications of a word list learning task using five different presentation durations (i.e. 1, 2, 5, 10 or 20 s/word). In agreement with previous observations, prolonged visual presentation of words significantly improved recall and recognition in demented subjects, whereas task practice did not improve memory performance. The performance in the demented sample after long presentation times (20 s/item) does not reach the level of performance of the comparison group after short presentation times (1 s/item). Consequently, it seems unlikely that memory dysfunction is caused by increased item processing times in patients with dementia. To reach comparable performance of demented and controls for intervention or activation studies, presentation times must be shortened below 1 s/item in the control sample.

Erythropoietin in amniotic fluid as a marker of chronic fetal hypoxia

OBJECTIVE

To determinate the erythropoietin concentration in amniotic fluid in normal pregnancies and pregnancies with suspected hypoxia.

METHOD

The erythropoietin concentration of 164 samples of amniotic fluid was determined by ELISA. The samples were taken by amniotomy during birth, as well as amniocentesis conducted during prenatal care.

RESULTS

A distribution of 1.07-7.29 U/l (10th-90th percentile) within the normal group (n = 106) was determined. Significantly elevated erythropoietin levels in amniotic fluid were determined in maternal hypertension (P = 0.039) and low birth-weight children (P = 0.0032). A correlation with the child's sex could be excluded.

CONCLUSION

Elevated erythropoietin levels in amniotic fluid indicated chronic fetal hypoxia.

Photometry and spectroscopy of the GRB 970508 optical counterpart

An optical transient within the error box of the gamma ray burst GRB 970508 was imaged 4 hours after the event. It displayed a strong ultraviolet excess, and reached maximum brightness 2 days later. The optical spectra did not show any emission lines, and no variations on time scales of minutes were observed for 1 hour during the decline phase. According to the fireball and afterglow models, the intensity should rise monotonically before the observed optical maximum, but the data indicate that another physical mechanism may be responsible for the constant phase seen during the first hours after the burst.