Microbial manganese and sulfate reduction in Black Sea shelf sediments

The microbial ecology of anaerobic carbon oxidation processes was investigated in Black Sea shelf sediments from mid-shelf with well-oxygenated bottom water to the oxic-anoxic chemocline at the shelf-break. At all stations, organic carbon (Corg) oxidation rates were rapidly attenuated with depth in anoxically incubated sediment. Dissimilatory Mn reduction was the most important terminal electron-accepting process in the active surface layer to a depth of ∼1 cm, while SO42− reduction accounted for the entire Corg oxidation below. Manganese reduction was supported by moderately high Mn oxide concentrations. A contribution from microbial Fe reduction could not be discerned, and the process was not stimulated by addition of ferrihydrite. Manganese reduction resulted in carbonate precipitation, which complicated the quantification of Corg oxidation rates. The relative contribution of Mn reduction to Corg oxidation in the anaerobic incubations was 25 to 73% at the stations with oxic bottom water. In situ, where Mn reduction must compete with oxygen respiration, the contribution of the process will vary in response to fluctuations in bottom water oxygen concentrations. Total bacterial numbers as well as the detection frequency of bacteria with fluorescent in situ hybridization scaled to the mineralization rates. Most-probable-number enumerations yielded up to 105 cells of acetate-oxidizing Mn-reducing bacteria (MnRB) cm−3, while counts of Fe reducers were <102 cm−3. At two stations, organisms affiliated with Arcobacter were the only types identified from 16S rRNA clone libraries from the highest positive MPN dilutions for MnRB. At the third station, a clone type affiliated with Pelobacter was also observed. Our results delineate a niche for dissimilatory Mn-reducing bacteria in sediments with Mn oxide concentrations greater than ∼10 μmol cm−3 and indicate that bacteria that are specialized in Mn reduction, rather than known Mn and Fe reducers, are important in this niche

ALTKAL: An optimum linear filter for GEOS-3 altimeter data

ALTKAL is a computer program designed to smooth sea surface height data obtained from the GEOS 3 altimeter, and to produce minimum variance estimates of sea surface height and sea surface slopes, along with their standard derivations. The program operates by processing the data through a Kalman filter in both the forward and backward directions, and optimally combining the results. The sea surface height signal is considered to have a geoid signal, modeled by a third order Gauss-Markov process, corrupted by additive white noise. The governing parameters for the signal and noise processes are the signal correlation length and the signal-to-noise ratio. Mathematical derivations of the filtering and smoothing algorithms are presented. The smoother characteristics are illustrated by giving the frequency response, the data weighting sequence and the transfer function of a realistic steady-state smoother example. Based on nominal estimates for geoidal undulation amplitude and correlation length, standard deviations for the estimated sea surface height and slope are 12 cm and 3 arc seconds, respectively

Clinical relevance and treatment possibilities of bipolar rapid cycling

Bipolar rapid cycling (RC) is defined as 4 or more affective episodes within 1 year. It has been postulated that RC is related to a poor response to lithium, to the same extent as mixed episodes or other atypical symptoms of the illness. This article reviews the current status of alternative pharmacological or otherwise supportive therapies of RC. Biological parameters and characteristics of the illness associated with RC like gender prevalence in women, hyperthyroid ism, catecholamine-O-methyltransferase allele, the influence of sleep, different subtypes of bipolar disorder and the risk of antidepressant-induced cycling will be discussed in detail. Copyright (C) 2002 S. Karger AG, Basel

Clozapine as add-on medication in the maintenance treatment of bipolar and schizoaffective disorders - A case series

Atypical neuroleptics are increasingly used in the treatment of bipolar and schizoaffective disorders. Currently, numerous controlled short-term studies are available for clozapine, olanzapine, risperidone or quetiapine, but long-term data are still missing. Three patients (2 with bipolar disorder, 1 with schizoaffective disorder) are described who showed a marked reduction of affective symptomatology after clozapine had been added to mood stabilizer pretreatment. The patients were seen once a month before and after the introduction of clozapine for at least 6 months. Treatment response was evaluated using different rating scales (IDS, YMRS; GAF; CGIBP) and the NIMH Life Chart Methodology. All patients showed a marked improvement after the add-on treatment with clozapine had been initiated. Clozapine was tolerated well with only transient and moderate weight gain and fatigue as only side effects. This case series underlines the safety and efficacy of clozapine as add-on medication in the treatment of bipolar and schizoaffective disorders. Copyright (C) 2002 S. Karger AG, Basel

Adding low-dose antidepressants to interferon alpha treatment for chronic hepatitis C improved psychiatric tolerability in a patient with schizoaffective psychosis

Treatment of chronic hepatitis C with interferon alpha (IFN-alpha) is relatively contraindicated in patients with psychiatric disorders because of possible severe psychiatric side effects. We report on a case of a female patient with a chronic schizoaffective psychosis, who was treated for 3 months with 3 x 3 mio IE IFN-alpha s.c./week because of a chronic hepatitis C (genotype Ib). Psychosis was stable with flupentixol monotherapy. After 2 months, she developed a severe depressive syndrome which lead to suicidal ideation. Until this time, she was without any antidepressive medication. Depressive symptoms disappeared after interferon therapy was stopped. Under prophylactic treatment with low-dose trimipramine (50 mg) or nefazodone (200 mg/day) therapy with IFN-alpha 3 x 3 mio IE/week was re-established after several months and again 2 years later adding ribavirin 1200 mg/day, a virustaticum. In contrast to the symptoms during monotherapy with IFN-alpha, during the time of both combination treatments, no psychiatric side effects occurred. While for ribavirin antidepressant effects are not known, we suppose that antidepressants may in serotonergic or noradrenergic caused by IFN-alpha. prevent changes neurotransmission caused by IFN-alpha. Copyright (C) 2000 S. Karger AG, Basel

Combined use of 16S ribosomal DNA and 16S rRNA to study the bacterial community of polychlorinated biphenyl-polluted soil

The bacterial diversity assessed from clone libraries prepared from rRNA (two libraries) and ribosomal DNA (rDNA) (one library) from polychlorinated biphenyl (PCB)-polluted soil has been analyzed. A good correspondence of the community composition found in the two types of library was observed. Nearly 29% of the cloned sequences in the rDNA library were identical to sequences in the rRNA libraries. More than 60% of the total cloned sequence types analyzed were grouped in phylogenetic groups (a clone group with sequence similarity higher than 97% [98% for Burkholderia andPseudomonas-type clones]) represented in both types of libraries. Some of those phylogenetic groups, mostly represented by a single (or pair) of cloned sequence type(s), were observed in only one of the types of library. An important difference between the libraries was the lack of clones representative of the Actinobacteriain the rDNA library. The PCB-polluted soil exhibited a high bacterial diversity which included representatives of two novel lineages. The apparent abundance of bacteria affiliated to the beta-subclass of theProteobacteria, and to the genus Burkholderiain particular, was confirmed by fluorescence in situ hybridization analysis. The possible influence on apparent diversity of low template concentrations was assessed by dilution of the RNA template prior to amplification by reverse transcription-PCR. Although differences in the composition of the two rRNA libraries obtained from high and low RNA concentrations were observed, the main components of the bacterial community were represented in both libraries, and therefore their detection was not compromised by the lower concentrations of template used in this study

Intrinsic Pinning in the High Field C-Phase of UPt_3

We report on the a.c. magnetic response of superconducting UPt_3 in a d.c. magnetic field. At low fields (H < H^*), the in-phase susceptibility shows a sharp drop at $T_c$ followed by a gradual decrease with decreasing temperature, while the out-of-phase component shows a large peak at T_c followed by an unusual broad peak. As the B-C phase line is crossed (H>H^*), however, both the in-phase and out-of-phase susceptibilities resemble the zero-field Meissner curves. We interpret these results in terms of a vortex pinning force which, while comparatively small in the A/B-phases, becomes large enough to effectively prevent vortex motion in the C-phase.Comment: Modified discussion, slight changes to figures, accepted in PRB Rapid Communications. RevTex file, 5 figure

Late recurrent ischaemia in infarct patients with a normal predischarge exercise test after thrombolysis

We investigated the prognostic value of normal predischarge exercise test in 109 patients after myocardial infarction treated with i. v. thrombolysis within 4 h. In 29 of these 109 patients, elective PTCA or bypass surgery was performed for prognostic reasons after coronary angiography; 80 patients were treated conservatively with drug therapy. Recurrent postinfarct angina early after hospital discharge was the reason in 4 of 80 for PTCA or bypass surgery. Twenty-three of the remaining 76 conservatively treated patients developed recurrent ischaemia during long-term follow-up of 12.0 ± 6.2 months, including one patient with reinfarction. Late recurrent ischaemia during long-term follow-up was observed in one third of the conservatively treated patients with a normal predischarge exercise test, although a high percentage (30%) of patients in this subgroup had been treated with PTCA or bypass surgery mainly for prognostic reasons. Predischarge exercise test is therefore of limited value for detection of still viable myocardium at risk of further ischaemic events after acute myocardial infarction and thrombolysi

Improved sensitivity of whole-cell hybridization by the combination of horseradish peroxidase-labeled oligonucleotides and tyramide signal amplification

The substrate fluorescein-tyramide was combined with oligonucleotide probes directly labeled with horseradish peroxidase to improve the sensitivity of in situ hybridization of whole fixed bacterial cells. Flow cytometry and quantitative microscopy of cells hybridized by this technique showed 10- to 20-fold signal amplifications relative to fluorescein-manolabeled probes. The application of the new technique to the detection of natural bacterial communities resulted in very bright signals; however, the number of detected cells was significantly lower than that detected with fluorescently monolabeled, rRNA-targeted oligonucleotide probes