B2 bradykinin receptors in cultured neonatal rat cardiomyocytes mediate a negative chronotropic and negative inotropic response

Receptors for bradykinin (BK) were characterized in primary cultures of beating neonatal rat cardiomyocytes using [3H]BK was radioligand. Degradation studies demonstrated that [3H]BK was stable for at least 2 h when incubated with cardiomyocytes at 2 and 37 degrees C in the presence of bacitracin in combination with captopril or ramiprilat. Without these inhibitors, > 80% of the [3H]BK was degraded within 2 h at 37 degrees C. This indicates that angiotensin-converting enzyme (ACE) is responsible for the main BK-degrading activity in cardiomyocytes. Scatchard plots were linear and gave a Kd of 1.5 +/- 0.8 nmol/l (mean +/- SD, n = 4) and a maximum binding capacity of 55-125 fmol/mg protein. Association and dissociation studies showed that binding of [3H]BK was saturable and reversible. Binding of [3H]BK at 37 degrees C led to internalization of the ligand. Competition studies with B1 and B2 agonists and antagonists were consistent with a B2 subtype of receptor. Addition of BK to beating cardiomyocytes (> 1 nmol/l) at 37 degrees C gave a strong but transient negative chronotropic effect. This response was paralleled by changes in the pulsation amplitude, which indicated a simultaneous negative inotropic effect of BK. These results provide a basis for the hypothesis that ACE inhibition exerts its cardioprotective effect at the level of a population of cardiomyocytes by virtue of kinin receptor-mediated mechanisms.

Assignment of genes encoding GABAA receptor subunits alpha 1, alpha 6, beta 2, and gamma 2 to a YAC contig of 5q33

A gene cluster consisting of the four gamma-aminobutyric acidA (GABAA) receptor subunit genes GABRA1, GABRA6, GABRAB2, and GABRG2 was assigned to a yeast artificial chromosome (YAC) contig of 5q33. Two of the 26 YACs of the contig are positive for all four subunit genes. The order of the GABR subunit genes with respect to known anonymous gene loci is cen-D5S380 - D5S403 - D5S529 - GABRB2 - GABRA1/A6 - GABRG2-D 5S422-tel. This novel YAC contig lies between known YAC contigs of 5q34/q35 and 5q31-q33.

[Heparin-induced thrombocytopenia. Results from the Comprehensive Hospital Drug Monitoring (CHDM) Bern/St. Gallen]

Of 23,520 consecutive hospitalizations from 1980-1988 (corresponding to 16,628 individual patients) in three departments of general internal medicine, 8261 were treated with heparin. All observations of patients displaying a probable, possible or questionable relationship of thrombocytopenia to heparin (administered i.v. or subcutaneously) were electronically collected by the CHDM program, revised on the basis of the primary case records and selected by standardized criteria. 13 of the 8261 patients exposed to heparin were considered to have a probable or possible HIT, corresponding to a frequency of 0.157%. In two of them severe thrombocytopenia was observed (corresponding to 0.024%) accompanied in one case by a white clot syndrome. Thrombocytopenia was defined as a platelet value below 100 x 10(9)/l and severe thrombocytopenia as one below 30 x 10(9)/l. In the literature we found slight, asymptomatic thrombocytopenia in < or = 1-8% of heparin treated patients. Our result of 11 out of 8261 (corresponding to 0.133%) is low, partly because the thrombocyte count was not controlled systematically, the heparin used was mainly produced from swine intestinal mucosa, and no antibody tests had been carried out. To prevent severe thrombocytopenia from heparin we propose monitoring the platelet count if the treatment is to be continued for more than 5 days. The newer low molecular weight heparins, all of swine origin, are much safer compared to the traditional preparations in regard to risk of HIT and white clot syndrome.

Immune defence in mice lacking type I and/or type II interferon receptors

Mice lacking the receptor for type I interferon (IFN-alpha beta, A129 mice), for type II interferon (IFN-gamma, G129 mice) or for both receptors (AG129 mice) have been generated by embryonic stem cell mediated gene targeting and inter-crossing A129 x G129, respectively. The role of the two IFN systems in controlling a range of infections has been studied using these mice. Type I IFN is shown to be responsible for the immune defence against most viral infections tested (Lymphocytic Choriomeningitis Virus, Semliki Forest Virus, Theiler's Virus, Vesicular Stomatitis Virus), type II IFN seems to be of little importance. In Vaccinia Virus and Theiler's Virus infection, however, both IFN systems were found to play a nonredundant role. IFN-gamma was critical for the defence against intracellular bacteria (Mycobacterium, Listeria) and parasites (Leishmania), whereas IFN-alpha beta was not. IFN-alpha beta is produced by virus-infected cells within hours and plays an important role in preventing virus spread early. Production of IFN-gamma on the other hand needs activation of the immune system and plays a major role later, i.e. mostly during the immune response. Data obtained with the mice described here show that both IFN systems seem to have evolved to complement each other in the host defence against a wide variety of infectious agents.

Apolipoprotein E genotype in patients with Alzheimer's disease: implications for the risk of dementia among relatives

Numerous studies have shown that the risk of Alzheimer's disease (AD) is associated with the dose of the epsilon 4 allele of apolipoprotein E (ApoE). However, more than one third of AD patients lack epsilon 4 and many persons having epsilon 4 survive cognitively intact to old age. We evaluated the lifetime risk of disease in 3,999 first-degree relatives of 549 probands who met the criteria for probable or definite AD and whose ApoE genotypes were known. ApoE genotypes for relatives were not determined. After age 65 the risk among relatives was proportional, as much as 7 to 10% at age 85, to the number of epsilon 4 alleles present in the proband. Risks to relatives of ApoE 2/2 and 2/3 probands were nearly identical at all ages to risks for relatives of ApoE 3/3 probands. The expected proportion of relatives having at least one epsilon 4 allele was calculated for each genotype group based on the distribution of parents, sibs, and offspring in the sample. Among relatives in the ApoE 3/3 group, the lifetime risk for AD by age 90 was three times greater than the expected proportion of epsilon 4 carriers, suggesting that factors other than ApoE contribute to AD susceptibility. Furthermore, the 44% risk of AD by age 93 among relatives of ApoE 4/4 probands indicates that as many as 50% of people having at least one epsilon 4 allele do not develop AD. We also found that among male relatives, risk of AD in the ApoE 3/4 group was similar to that for the ApoE 3/3 group but significantly less than the risk for the ApoE 4/4 group. In contrast, among female relatives the risk for the ApoE 3/4 group was nearly twice that for the ApoE 3/3 group and identical to the risk for the ApoE 4/4 group. These findings are consistent with a sex-modification effect of the E4 isoform on disease susceptibility.

The nitric oxide/cGMP system in the antennal lobe of Apis mellifera is implicated in integrative processing of chemosensory stimuli

The high concentration and the localization of nitric oxide synthase in the olfactory system of both vertebrates and invertebrates suggest that the diffusible messenger nitric oxide plays a central role in the processing of chemosensory information. This paper describes the nitric oxide releasing system in the antenna and the antennal lobes of Apis mellifera using the NADPH diaphorase technique, and analyses the contribution of the nitric oxide system in the neuronal processing of chemosensory signals using a behavioral assay in vivo. In the antenna the strongest NADPH diaphorase staining is found in non-neuronal auxiliary and/or epithelial cells, while the sensory cells and the antennal nerve are stained at a low level. At the major site of chemosensory signal integration, the antennal lobes, the highest nitric oxide synthase activity is located in the glomeruli, which are ideally suited to act as diffusion compartments. We demonstrate that inhibition of nitric oxide synthase in the antennal lobes specifically interferes with neuronal processing of repetitive chemosensory stimuli but does not affect the response to single stimuli, and is independent of parameters such as satiation level, stimulus strength, interstimulus interval and duration of sensory stimuli. Since inhibition of the soluble guanylate cyclase, a major target of nitric oxide, also particularly affects the adaptive component, the physiological effects of nitric oxide appear to be mediated by the action of cGMP. These findings suggest that the nitric oxide/cGMP system in the antennal lobes is a component of the molecular machinery involved in adaptive and/or integrative mechanisms during chemosensory information processing in vivo.

A twelve-month comparative clinical investigation of two low-dose oral contraceptives containing 20 micrograms ethinylestradiol/75 micrograms gestodene and 20 micrograms ethinylestradiol/150 micrograms desogestrel, with respect to efficacy, cycle control and tolerance

The aim of this study was to compare contraceptive reliability, cycle control and tolerance of an oral contraceptive containing 20 micrograms ethinylestradiol and 75 micrograms gestodene, with a reference preparation containing the same dose of estrogen combined with 150 micrograms desogestrel. This article presents interim data from centers in France and Austria, involving a total of 479 women and 4,991 cycles. Contraceptive reliability was good with both preparations. Two pregnancies occurred in the gestodene group, but neither were due to method failure. In the desogestrel group there were also two pregnancies, of which one was due to method failure. With respect to cycle control, there is a trend towards a lower incidence of intermenstrual bleeding in the gestodene group. The incidence of spotting (scanty bleeding) during the important first three cycles was 3.5% lower in the gestodene group, and over the first six cycles, it was 7.6% lower. Amenorrhea was similar in both groups, but the incidence of dysmenorrhea was significantly lower in the gestodene group (p=0.001). Adverse events were similar in both groups, with headache, breast tension and nausea the most frequently reported symptoms. Body weight remained relatively constant during treatment in both groups, and no hypertension was reported for any woman during the course of the study. In each treatment group, 19 women discontinued because of adverse events. It is concluded that both preparation are reliable and well tolerated oral contraceptives are reliable and well tolerated oral contraceptives; however, there is a more favourable effect on dysmenorrhea by the gestodene formulation.

Assignment of the dystonia-parkinsonism syndrome locus, DYT3, to a small region within a 1.8-Mb YAC contig of Xq13.1

A YAC contig was constructed of Xq13.1 in order to sublocalize the X-linked dystonia-parkinsonism (XDP) syndrome locus, DYT3. The contig spans a region of approximately 1.8 Mb and includes loci DXS453/DXS348/IL2R gamma/GJB1/CCG1/DXS559. For the construction of the contig, nine sequence-tagged sites and four short tandem repeat polymorphisms (STRPs) were isolated. The STRPs, designated as 4704#6 (DXS7113), 4704#7 (DXS7114), 67601 (DXS7117), and B4Pst (DXS7119) were assigned to a region flanked by DXS348 proximally and by DXS559 distally. Their order was DXS348/4704 #6/4704 #7/67601/B4Pst/DXS559. They were applied to the analysis of allelic association and of haplotypes in 47 not-obviously-related XDP patients and in 105 Filipino male controls. The same haplotype was found at loci 67601 (DXS7117) and B4Pst (DXS7119) in 42 of 47 patients. This percentage of common haplotypes decreased at the adjacent loci. The findings, together with the previous demonstration of DXS559 being the distal flanking marker of DYT3, assign the disease locus to a small region in Xq13.1 defined by loci 67601 (DXS7117) and B4Pst (DXS7119). The location of DYT3 was born out by the application of a newly developed likelihood method for the analysis of linkage disequilibrium.

Spinocerebellar ataxia, type 3 (SCA3) is genetically identical to Machado-Joseph disease (MJD)

Spinocerebellar ataxia, type 3 (SCA3) and Machado-Joseph disease (MJD) are two clinically distinct representatives of the heterogeneous group of autosomal dominant cerebellar ataxias. Assignment of the disease genes to the same region of the long arm of chromosome 14 in both SCA3 and MJD suggested that these two disorders are genetically identical. The recent identification of a trinucleotide (CAG) repeat expansion in a gene underlying MJD facilitates assessment of this hypothesis. We analysed the MJD gene in members of a family with characteristic features of SCA3 and no symptoms typical of MJD. We found the same trinucleotide repeat expansion within the gene that was previously described in patients with MJD. The findings demonstrate that SCA3 and MJD are genetically identical in spite of their pronounced clinical differences. Furthermore, we demonstrate a striking variation in the copy number of the CAG repeat among affected members of the same family.

Antiviral defense in mice lacking both alpha/beta and gamma interferon receptors

Alpha/beta interferon (IFN) and gamma IFN exert widely overlapping biological effects. Still, mice with individually inactivated alpha/beta or gamma receptors exhibit variably severely reduced resistance to infection and altered immune responses. To investigate to what extent the two IFN systems are functionally redundant, we generated mice with a combined receptor defect (AG129 mice). Like mice with individual mutations, AG129 mice had no apparent anomalies, confirming that in the mouse the IFN system is not essential for normal development. These mice showed an additive phenotype with respect to antiviral defense and exhibited an increased susceptibility to lymphocytic choriomeningitis virus (LCMV) and notably vaccinia virus infection. Because of unlimited replication and subsequent rapid exhaustion of cytotoxic T lymphocyte (CTL) precursors, these mice were unable to mount a CTL response to LCMV. CD8(+)-mediated immunopathology was absent in LCMV-infected mice, and virus persisted. Vaccinia virus replicated much faster in AG129 mice, and a 10(4)-fold lower dose of vaccinia virus was sufficient to prime these mice. With the normal priming dose of 10(6) PFU, cytopathic effects and overwhelming infection possibly causing partial exhaustion of CTL interfered with the anti-vaccinia virus response. Even though global antiviral immunoglobulin G (IgG) titers were within normal ranges, the IgG subclass distribution was heavily biased toward IgG1.

Prolonged pretreatment with alpha-lipoic acid protects cultured neurons against hypoxic, glutamate-, or iron-induced injury

The antioxidant dihydrolipoic acid has been shown to reduce hypoxic and excitotoxic neuronal damage in vitro. In the present study, we tested whether pretreatment with alpha-lipoic acid, which presumably allows endogenous formation of dihydrolipoic acid, can protect cultured neurons against injury caused by cyanide, glutamate, or iron ions, using the trypan blue exclusion method to determine neuronal damage. One hour of preincubation with dihydrolipoic acid (1 microM), but not with alpha-lipoic acid, reduced damage of neurons from chick embryo telencephalon caused by 1 mM sodium cyanide or iron ions. alpha-Lipoic acid (1 microM) reduced cyanide-induced neuronal damage when added 24 h before hypoxia, and pretreatment with alpha-lipoic acid for > 24 h enhanced this neuroprotective effect. Both the R- and the S-enantiomer of alpha-lipoic acid exerted a similar neuroprotective effect. Pretreatment with alpha-lipoic acid (1 microM) from the day of plating onward prevented the degeneration of chick embryo telencephalic neurons that had been exposed to Fe2+/Fe3+. alpha-Lipoic acid (1 microM) added to the culture medium the day of plating also reduced neuronal injury induced by 1 mM L-glutamate in rat hippocampal cultures, whereas 30 min of preincubation with alpha-lipoic acid failed to attenuate glutamate-induced neuronal damage. Our results indicate that neuroprotection by prolonged pretreatment with alpha-lipoic acid is probably due to the radical scavenger properties of endogenously formed dihydrolipoic acid.

Identification and characterization of the Arabidopsis thaliana chloroplast DNA region containing the genes psbA, trnH and rps19'

A 1887-nucleotide chloroplast-DNA region from Arabidopsis thaliana was analyzed. It contains the conserved genes psbA for the precursor of the D1 reaction-centre protein of photosystem II, trnH for tRNAHis, and rps19' for the 6.8-kDa protein of the small ribosomal subunit. Northern hybridization and RNase protection experiments suggest co-transcription of a minor RNA fraction over the full lengths of psbA and the preceding trnK-UUU gene, but not including downstream trnH sequences. In front of the mapped 5' end of the major 1.2-kb psbA transcript is a DNA region that shows the typical architecture of a psbA promoter, consisting of the prokaryotic-type '-35' and '-10' elements as well as the eukaryotic-type 'TATA' motif. The common 3' end of psbA transcripts seems to be located immediately after a stem-loop structure downstream from the coding region.

Predisposition for cysteine substitutions in the immunoglobulin-like chain of FGFR2 in Crouzon syndrome

Four cases of Crouzon syndrome, one familial and three sporadic, were investigated for mutations in exon B of the fibroblast growth factor receptor 2 (FGFR2) gene. In the familial case, a mutation was found at codon 340 that exchanged tyrosine for histidine. Mutations at codon 342, detected in the three sporadic cases, replaced a cysteine by another amino acid. While three of the mutations have been described before, the fourth mutation, a C-->G transversion at codon 342 in one of the sporadic cases, has not been recognized previously. Compilation of all exon B mutations in Crouzon syndrome described to date revealed that 6 of the 8 sporadic and 2 of the 9 familial cases have mutations in codon 342. These mutations caused the substitution of cysteine for another amino acid. Given that a mutation in codon 342 was found in 8 out of 17 cases and that in 9 cases the mutation occurred at five additional positions, codon 342 of exon B of the FGFR2 gene may be predisposed to mutations in Crouzon syndrome.

Aggressive behavior and altered amounts of brain serotonin and norepinephrine in mice lacking MAOA

Deficiency in monoamine oxidase A (MAOA), an enzyme that degrades serotonin and norepinephrine, has recently been shown to be associated with aggressive behavior in men of a Dutch family. A line of transgenic mice was isolated in which transgene integration caused a deletion in the gene encoding MAOA, providing an animal model of MAOA deficiency. In pup brains, serotonin concentrations were increased up to ninefold, and serotonin-like immunoreactivity was present in catecholaminergic neurons. In pup and adult brains, norepinephrine concentrations were increased up to twofold, and cytoarchitectural changes were observed in the somatosensory cortex. Pup behavioral alterations, including trembling, difficulty in righting, and fearfulness were reversed by the serotonin synthesis inhibitor parachlorophenylalanine. Adults manifested a distinct behavioral syndrome, including enhanced aggression in males.

Theiler's virus infection of 129Sv mice that lack the interferon alpha/beta or interferon gamma receptors

The Daniels strain of Theiler's virus causes a persistent infection of the white matter of spinal cord of susceptible mice, with chronic inflammation and primary demyelination. Inbred 129Sv mice are resistant to this infection; they present with mild encephalomyelitis and clear the infection within a matter of days. A very different outcome was observed with inbred 129Sv mice whose receptors for interferon alpha/beta or interferon gamma had been inactivated by homologous recombination. The former presented severe encephalomyelitis with acute infection of neurons, particularly in brain and hippocampus, and extensive infection with necrosis of the choroid plexus. Most animals died of this acute disease. The latter, presented the same early encephalomyelitis as the control 129Sv mice. However, they remained persistently infected and developed a very severe late infection of the white matter with extensive primary demyelination. This late disease looked like an exacerbated form of the chronic demyelinating disease observed in susceptible inbred mice such as the SJL/J or FVB strains. Our results show that the two interferon systems play nonredundant roles in the resistance of the 129Sv mouse to the infection by Theiler's virus. They also lend support to the notion that the Ifg gene is involved in the resistance/susceptibility of inbred strains of mice to persistent infection by this picornavirus.

Activation of (R)-2-hydroxyglutaryl-CoA dehydratase from Acidaminococcus fermentans

(R)-2-Hydroxyglutaryl-CoA dehydratase (HgdAB) from Acidaminococcus fermentans catalyses the reversible dehydration of its substrate to glutaconyl-CoA. The enzyme has to be activated by ATP, MgCl2, and Ti(III)citrate by an activator protein (HgdC) that is present in the organism at very low concentrations. Cell-free extracts of a recombinant Escherichia coli strain, in which hgdC was expressed, contained the activator with a specific activity of up to 45 U'/mg protein (1 U' is the amount of activator required to generate 1 U dehydratase activity under standard assay conditions). The recombinant protein was purified 44-fold to a specific activity of 2000 U'/mg. It is a homodimer (gamma 2, 54 kDa) and contains 4 mol non-heme iron and 3 mol inorganic sulfur. Under air, the activator has a half-life of seconds and even under strict anaerobic conditions it is very unstable. The amino acid sequence of the activator shows similarities to the ATP-binding motifs of several kinases. The dehydratase component was purified from its natural source revealing a heterodimer (alpha beta, 100 kDa) that contains 4 mol non-heme iron, 4 mol inorganic sulfur, 0.3 mol riboflavin, and 1 mol FMN. A mechanism is proposed in which an iron-sulfur cluster or a flavin donates one electron to the thiolester of the substrate (R)-2-hydroxyglutaryl-CoA. The resulting ketyl may eliminate the adjacent hydroxyl group yielding an enoxy radical from which the beta-hydrogen is abstracted as a proton leading to the ketyl of glutaconyl-CoA. In the final step, the latter is oxidized to the product, whereby the reduced enzyme is regenerated. It is suggested that during the activation step, the electron of this cycle is fed into the enzyme by Ti(III)citrate and energized by hydrolysis of ATP; both functions are apparently catalysed by the activator. The enzyme remains in this activated state for several turnovers, which may explain the requirement of only catalytic amounts of ATP and substoichiometric amounts of activator (dehydratase/activator ratio approximately 200:1). The oxidants 4-nitrobenzoate, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone or chloramphenicol (all at concentrations greater than or equal to 1 microM) may trap this electron resulting in a reversible, transient inactivation of the dehydratase.

PKA activity in the antennal lobe of honeybees is regulated by chemosensory stimulation in vivo

The involvement of cyclic nucleotide cascades has been suggested for chemosensory signal processing as well as synaptic plasticity. Cyclic AMP-dependent protein kinase (PKA) is a major mediator for transient changes in these second messengers. The objective of this study was to examine the role of PKA in the central processing of chemosensory information by the honeybee. Effects of chemosensory stimulation in vivo were detected in the first chemosensory neuropil of the honeybee brain, the antennal lobe (AL), by using a combination of shock freezing and specific determination of PKA activity. Mechanosensory or odor stimulation of the antennae had no effect on PKA activity. Brief application of aqueous solutions (pure water or sucrose solution) to an antenna caused a rapid and transient elevation of PKA activity in the ipsilateral AL. A series of such stimuli led to a graded increase in PKA activity followed by a rapid decrease during the first 10 s after the end of stimulation, but elevated levels of PKA activity were observed for as long as 1 min. These results suggest that PKA activity and its regulation contribute to central processing of chemosensory signals.

[Salmonella diagnosis and expanded bacteriologic differential diagnosis using Rambach agar]

The present study gives not only additional advises and ideas for the use of Rambach agar but also diagnostic support. Resulting from several years of diagnostic experience the medium can be recommended for enlarged routine differential-diagnosis of bacteria and also for improved Salmonella-diagnosis as an alternative medium (under section 35 LMBG; Untersuchung von Lebensmitteln; Nachweis von Salmonellen).

Octopamine mediates rapid stimulation of protein kinase A in the antennal lobe of honeybees

In the honeybee octopamine mediates mechanisms of arousal that interfere with the appetitive proboscis extension response to food-indicating chemosensory stimuli. This study demonstrates that injections of octopamine or cyclic adenosine monophosphate (cAMP) into the primary chemosensory neuropil of the honeybee, the antennal lobe, evokes a rapid and transient activation of cAMP-dependent protein kinase (PKA). Other monoamines detectable in the antennal lobe, dopamine and serotonin, do not affect the level of PKA activity. Stimulation of the bees' antenna with the appetitive stimulus water or sucrose solution in vivo also causes a short-term activation of PKA in the antennal lobe. The increased PKA activity can be detected immediately (0.5 s) after stimulation but reverts to the basal level within 3 s. This effect can be abolished by monoamine depletion with reserpine. Since octopamine is the only monoamine that stimulates PKA, it appears to mediate the PKA activation after sucrose stimulus and may contribute to the processing of this chemosensory input.