Metatranscriptomics sheds light on the links between the functional traits of fungal guilds and ecological processes in forest soil ecosystems

Soil fungi belonging to different functional guilds, such as saprotrophs, pathogens, and mycorrhizal symbionts, play key roles in forest ecosystems. To date, no study has compared the actual gene expression of these guilds in different forest soils. We used metatranscriptomics to study the competition for organic resources by these fungal groups in boreal, temperate, and Mediterranean forest soils. Using a dedicated mRNA annotation pipeline combined with the JGI MycoCosm database, we compared the transcripts of these three fungal guilds, targeting enzymes involved in C- and N mobilization from plant and microbial cell walls. Genes encoding enzymes involved in the degradation of plant cell walls were expressed at a higher level in saprotrophic fungi than in ectomycorrhizal and pathogenic fungi. However, ectomycorrhizal and saprotrophic fungi showed similarly high expression levels of genes encoding enzymes involved in fungal cell wall degradation. Transcripts for N-related transporters were more highly expressed in ectomycorrhizal fungi than in other groups. We showed that ectomycorrhizal and saprotrophic fungi compete for N in soil organic matter, suggesting that their interactions could decelerate C cycling. Metatranscriptomics provides a unique tool to test controversial ecological hypotheses and to better understand the underlying ecological processes involved in soil functioning and carbon stabilization.

Ectomycorrhizal symbiosis prepares its host locally and systemically for abiotic cue signaling

Tree growth and survival are dependent on their ability to perceive signals, integrate them, and trigger timely and fitted molecular and growth responses. While ectomycorrhizal symbiosis is a predominant tree-microbe interaction in forest ecosystems, little is known about how and to what extent it helps trees cope with environmental changes. We hypothesized that the presence of Laccaria bicolor influences abiotic cue perception by Populus trichocarpa and the ensuing signaling cascade. We submitted ectomycorrhizal or non-ectomycorrhizal P. trichocarpa cuttings to short-term cessation of watering or ozone fumigation to focus on signaling networks before the onset of any physiological damage. Poplar gene expression, metabolite levels, and hormone levels were measured in several organs (roots, leaves, mycorrhizas) and integrated into networks. We discriminated the signal responses modified or maintained by ectomycorrhization. Ectomycorrhizas buffered hormonal changes in response to short-term environmental variations systemically prepared the root system for further fungal colonization and alleviated part of the root abscisic acid (ABA) signaling. The presence of ectomycorrhizas in the roots also modified the leaf multi-omics landscape and ozone responses, most likely through rewiring of the molecular drivers of photosynthesis and the calcium signaling pathway. In conclusion, P. trichocarpa-L. bicolor symbiosis results in a systemic remodeling of the host's signaling networks in response to abiotic changes. In addition, ectomycorrhizal, hormonal, metabolic, and transcriptomic blueprints are maintained in response to abiotic cues, suggesting that ectomycorrhizas are less responsive than non-mycorrhizal roots to abiotic challenges.

Stable functional structure despite high taxonomic variability across fungal communities in soils of old-growth montane forests

BACKGROUND

Major advances over the past decade in molecular ecology are providing access to soil fungal diversity in forest ecosystems worldwide, but the diverse functions and metabolic capabilities of this microbial community remain largely elusive. We conducted a field survey in montane old-growth broadleaved and conifer forests, to investigate the relationship between soil fungal diversity and functional genetic traits. To assess the extent to which variation in community composition was associated with dominant tree species (oak, spruce, and fir) and environmental variations in the old-growth forests in the Jade Dragon Snow Mountain in Yunnan Province, we applied rDNA metabarcoding. We also assessed fungal gene expression in soil using mRNA sequencing and specifically assessed the expression of genes related to organic matter decomposition and nutrient acquisition in ectomycorrhizal and saprotrophic fungi.

RESULTS

Our taxonomic profiling revealed striking shifts in the composition of the saprotrophic and ectomycorrhizal guilds among the oak-, fir-, and spruce-dominated forests. The core fungal microbiome comprised only ~ 20% of the total OTUs across all soil samples, although the overlap between conifer-associated communities was substantial. In contrast, seasonality and soil layer explained only a small proportion of the variation in community structure. However, despite their highly variable taxonomic composition, fungal guilds exhibited remarkably similar functional traits for growth-related and core metabolic pathways across forest associations, suggesting ecological redundancy. However, we found that the expression profiles of genes related to polysaccharide and protein degradation and nutrient transport notably varied between and within the fungal guilds, suggesting niche adaptation.

CONCLUSIONS

Overall, our metatranscriptomic analyses revealed the functional potential of soil fungal communities in montane old-growth forests, including a suite of specialized genes and taxa involved in organic matter decomposition. By linking genes to ecological traits, this study provides insights into fungal adaptation strategies to biotic and environmental factors, and sheds light on the importance of understanding functional gene expression patterns in predicting ecosystem functioning. Video Abstract.

Desert truffle genomes reveal their reproductive modes and new insights into plant-fungal interaction and ectendomycorrhizal lifestyle

Desert truffles are edible hypogeous fungi forming ectendomycorrhizal symbiosis with plants of Cistaceae family. Knowledge about the reproductive modes of these fungi and the molecular mechanisms driving the ectendomycorrhizal interaction is lacking. Genomes of the highly appreciated edible desert truffles Terfezia claveryi Chatin and Tirmania nivea Trappe have been sequenced and compared with other Pezizomycetes. Transcriptomes of T. claveryi × Helianthemum almeriense mycorrhiza from well-watered and drought-stressed plants, when intracellular colonizations is promoted, were investigated. We have identified the fungal genes related to sexual reproduction in desert truffles and desert-truffles-specific genomic and secretomic features with respect to other Pezizomycetes, such as the expansion of a large set of gene families with unknown Pfam domains and a number of species or desert-truffle-specific small secreted proteins differentially regulated in symbiosis. A core set of plant genes, including carbohydrate, lipid-metabolism, and defence-related genes, differentially expressed in mycorrhiza under both conditions was found. Our results highlight the singularities of desert truffles with respect to other mycorrhizal fungi while providing a first glimpse on plant and fungal determinants involved in ecto to endo symbiotic switch that occurs in desert truffle under dry conditions.

Dual transcriptomics and proteomics analyses of the early stage of interaction between Caballeronia mineralivorans PML1(12) and mineral

Minerals and rocks represent essential reservoirs of nutritive elements for the long-lasting functioning of forest ecosystems developed on nutrient-poor soils. While the presence of effective mineral weathering bacteria was evidenced in the rhizosphere of different plants, the molecular mechanisms involved remain uncharacterized. To fill this gap, we combined transcriptomic, proteomics, geo-chemical and physiological analyses to decipher the potential molecular mechanisms explaining the mineral weathering effectiveness of strain PML1(12) of Caballeronia mineralivorans. Considering the early-stage of the interaction between mineral and bacteria, we identified the genes and proteins differentially expressed when: (i) the environment is depleted of certain essential nutrients (i.e., Mg and Fe), (ii) a mineral is added and (iii) the carbon source (i.e., glucose vs mannitol) differs. The integration of these data demonstrates that strain PML1(12) is capable of (i) mobilizing iron through the production of a non-ribosomal peptide synthetase-independent siderophore, (ii) inducing chemotaxis and motility in response to nutrient availability and (iii) strongly acidifying its environment in the presence of glucose using a suite of GMC oxidoreductases to weather mineral. These results provide new insights into the molecular mechanisms involved in mineral weathering and their regulation and highlight the complex sequence of events triggered by bacteria to weather minerals.

Transcriptome Analysis of Apple Leaves Infected by the Rust Fungus Gymnosporangium yamadae at Two Sporulation Stages

Apple rust disease caused by Gymnosporangium yamadae is one of the major threats to apple orchards. In this study, dual RNA-seq analysis was conducted to simultaneously monitor gene expression profiles of G. yamadae and infected apple leaves during the formation of rust spermogonia and aecia. The molecular mechanisms underlying this compatible interaction at 10 and 30 days postinoculation (dpi) indicate a significant reaction from the host plant and comprise detoxication pathways at the earliest stage and the induction of secondary metabolism pathways at 30 dpi. Such host reactions have been previously reported in other rust pathosystems and may represent a general reaction to rust infection. G. yamadae transcript profiling indicates a conserved genetic program in spermogonia and aecia that is shared with other rust fungi, whereas secretome prediction reveals the presence of specific secreted candidate effector proteins expressed during apple infection. Unexpectedly, the survey of fungal unigenes in the transcriptome assemblies of inoculated and mock-inoculated apple leaves reveals that G. yamadae infection may modify the fungal community composition in the apple phyllosphere at 30 dpi. Collectively, our results provide novel insights into the compatible apple-G. yamadae interaction and advance the knowledge of this heteroecious demicyclic rust fungus.

Anaerobic lignocellulolytic microbial consortium derived from termite gut: enrichment, lignocellulose degradation and community dynamics

BACKGROUND

Lignocellulose is the most abundant renewable carbon resource that can be used for biofuels and commodity chemicals production. The ability of complex microbial communities present in natural environments that are specialized in biomass deconstruction can be exploited to develop lignocellulose bioconversion processes. Termites are among the most abundant insects on earth and play an important role in lignocellulose decomposition. Although their digestive microbiome is recognized as a potential reservoir of microorganisms producing lignocellulolytic enzymes, the potential to enrich and maintain the lignocellulolytic activity of microbial consortia derived from termite gut useful for lignocellulose biorefinery has not been assessed. Here, we assessed the possibility of enriching a microbial consortium from termite gut and maintaining its lignocellulose degradation ability in controlled anaerobic bioreactors.

RESULTS

We enriched a termite gut-derived consortium able to transform lignocellulose into carboxylates under anaerobic conditions. To assess the impact of substrate natural microbiome on the enrichment and the maintenance of termite gut microbiome, the enrichment process was performed using both sterilized and non-sterilized straw. The enrichment process was carried out in bioreactors operating under industrially relevant aseptic conditions. Two termite gut-derived microbial consortia were obtained from Nasutitermes ephratae by sequential batch culture on raw wheat straw as the sole carbon source. Analysis of substrate loss, carboxylate production and microbial diversity showed that regardless of the substrate sterility, the diversity of communities selected by the enrichment process strongly changed compared to that observed in the termite gut. Nevertheless, the community obtained on sterile straw displayed higher lignocellulose degradation capacity; it showed a high xylanase activity and an initial preference for hemicellulose.

CONCLUSIONS

This study demonstrates that it is possible to enrich and maintain a microbial consortium derived from termite gut microbiome in controlled anaerobic bioreactors, producing useful carboxylates from raw biomass. Our results suggest that the microbial community is shaped both by the substrate and the conditions that prevail during enrichment. However, when aseptic conditions are applied, it is also affected by the biotic pressure exerted by microorganisms naturally present in the substrate and in the surrounding environment. Besides the efficient lignocellulolytic consortium enriched in this study, our results revealed high levels of xylanase activity that can now be further explored for enzyme identification and overexpression for biorefinery purposes.

Screening of Phytophagous and Xylophagous Insects Guts Microbiota Abilities to Degrade Lignocellulose in Bioreactor

Microbial consortia producing specific enzymatic cocktails are present in the gut of phytophagous and xylophagous insects; they are known to be the most efficient ecosystems to degrade lignocellulose. Here, the ability of these consortia to degrade ex vivo lignocellulosic biomass in anaerobic bioreactors was characterized in term of bioprocess performances, enzymatic activities and bacterial community structure. In a preliminary screening, guts of Ergates faber (beetle), Potosia cuprea (chafer), Gromphadorrhina portentosa (cockroach), Locusta migratoria (locust), and Gryllus bimaculatus (cricket) were inoculated in anaerobic batch reactors, in presence of grounded wheat straw at neutral pH. A short duration fermentation of less than 8 days was observed and was related to a drop of pH from 7 to below 4.5, leading to an interruption of gas and metabolites production. Consistently, a maximum of 180 mg_eq.COD of metabolites accumulated in the medium, which was related to a low degradation of the lignocellulosic biomass, with a maximum of 5 and 2.2% observed for chafer and locust gut consortia. The initial cell-bound and extracellular enzyme activities, i.e., xylanase and β-endoglucanase, were similar to values observed in the literature. Wheat straw fermentation in bioreactors leads to an increase of cell-bounded enzyme activities, with an increase of 145% for cockroach xylanase activity. Bacterial community structures were insect dependent and mainly composed of Clostridia, Bacteroidia and Gammaproteobacteria. Improvement of lignocellulose biodegradation was operated in successive batch mode at pH 8 using the most interesting consortia, i.e., locust, cockroaches and chafer gut consortia. In these conditions, lignocellulose degradation increased significantly: 8.4, 10.5, and 21.0% of the initial COD were degraded for chafer, cockroaches and locusts, respectively in 15 days. Consistently, xylanase activity tripled for the three consortia, attesting the improvement of the process. Bacteroidia was the major bacterial class represented in the bacterial community for all consortia, followed by Clostridia and Gammaproteobacteria classes. This work demonstrates the possibility to maintain apart of insect gut biological activity ex vivo and shows that lignocellulose biodegradation can be improved by using a biomimetic approach. These results bring new insights for the optimization of lignocellulose degradation in bioreactors.

Uncovering the Potential of Termite Gut Microbiome for Lignocellulose Bioconversion in Anaerobic Batch Bioreactors

Termites are xylophages, being able to digest a wide variety of lignocellulosic biomass including wood with high lignin content. This ability to feed on recalcitrant plant material is the result of complex symbiotic relationships, which involve termite-specific gut microbiomes. Therefore, these represent a potential source of microorganisms for the bioconversion of lignocellulose in bioprocesses targeting the production of carboxylates. In this study, gut microbiomes of four termite species were studied for their capacity to degrade wheat straw and produce carboxylates in controlled bioreactors. All of the gut microbiomes successfully degraded lignocellulose and up to 45% w/w of wheat straw degradation was observed, with the Nasutitermes ephratae gut-microbiome displaying the highest levels of wheat straw degradation, carboxylate production and enzymatic activity. Comparing the 16S rRNA gene diversity of the initial gut inocula to the bacterial communities in lignocellulose degradation bioreactors revealed important changes in community diversity. In particular, taxa such as Spirochaetes and Fibrobacteres that were highly abundant in the initial gut inocula were replaced by Firmicutes and Proteobacteria at the end of incubation in wheat straw bioreactors. Overall, this study demonstrates that termite-gut microbiomes constitute a reservoir of lignocellulose-degrading bacteria that can be harnessed in artificial conditions for biomass conversion processes that lead to the production of useful molecules.

Analysis of large 16S rRNA Illumina data sets: Impact of singleton read filtering on microbial community description

Next-generation sequencing technologies give access to large sets of data, which are extremely useful in the study of microbial diversity based on 16S rRNA gene. However, the production of such large data sets is not only marred by technical biases and sequencing noise but also increases computation time and disc space use. To improve the accuracy of OTU predictions and overcome both computations, storage and noise issues, recent studies and tools suggested removing all single reads and low abundant OTUs, considering them as noise. Although the effect of applying an OTU abundance threshold on α- and β-diversity has been well documented, the consequences of removing single reads have been poorly studied. Here, we test the effect of singleton read filtering (SRF) on microbial community composition using in silico simulated data sets as well as sequencing data from synthetic and real communities displaying different levels of diversity and abundance profiles. Scalability to large data sets is also assessed using a complete MiSeq run. We show that SRF drastically reduces the chimera content and computational time, enabling the analysis of a complete MiSeq run in just a few minutes. Moreover, SRF accurately determines the actual community diversity: the differences in α- and β-community diversity obtained with SRF and standard procedures are much smaller than the intrinsic variability of technical and biological replicates.

Efficient anaerobic transformation of raw wheat straw by a robust cow rumen-derived microbial consortium

A rumen-derived microbial consortium was enriched on raw wheat straw as sole carbon source in a sequential batch-reactor (SBR) process under strict mesophilic anaerobic conditions. After five cycles of enrichment the procedure enabled to select a stable and efficient lignocellulolytic microbial consortium, mainly constituted by members of Firmicutes and Bacteroidetes phyla. The enriched community, designed rumen-wheat straw-derived consortium (RWS) efficiently hydrolyzed lignocellulosic biomass, degrading 55.5% w/w of raw wheat straw over 15days at 35°C and accumulating carboxylates as main products. Cellulolytic and hemicellulolytic activities, mainly detected on the cell bound fraction, were produced in the earlier steps of degradation, their production being correlated with the maximal lignocellulose degradation rates. Overall, these results demonstrate the potential of RWS to convert unpretreated lignocellulosic substrates into useful chemicals.

Phosphohexose isomerase polymorphism in the domestic cat

Genetic variation of the enzyme phosphohexose isomerase (PHI) has been found in the erythrocytes of Australian domestic cats by horizontal starch gel electrophoresis at pH 8.2. Three complex patterns of isoenzymes, designated F, FS and S, were obtained migrating anodally. Limited family studies and the distribution of the three main phenotypes indicated that the polymorphism in controlled by two codominant autosomal alleles, PHIF and PHIS. Gene frequencies for PHIF and PHIS have been calculated as 0.036 and 0.964 respectively. Three additional variant forms have also been observed.

The AB blood group system of cats

Holmes (1950) and Eyquem, Podliachouk & Milot (1962) classified feline erythrocytes into two types according to their reactions with naturally occurring antibodies in cats' plasmas. Eyquem et al. (1962) designated the two antigens, A and B, and this nomenclature has been retained in the present study. The blood group system, AB, was investigated in more detail, both genetically and serologically. Frequencies of 73.3% A and 26.3% B were found in a survey of 1895 Brisbane cats and in addition, a new phenotype, AB, was discovered with a low incidence of 0.4%. The results of the serological testing and limited family information suggested that the AB phenotype is inherited and not due to blood chimaerism. Preliminary genetic studies indicated that the A gene is dominant to the B in the usual situation and hypotheses to explain the occurrence of the AB phenotype are discussed. The incidence of naturally occurring antibodies was investigated in cats, with 95% of blood type B having anti-A and only 35% of type A having anti-B. No subgroups of the A and B antigens were detected and no blood group substances were found in the salivas of 37 cats. There was no evidence of any serological relationship of the feline A and B antigens with the human ABO antigens.

A biallelic gene polymorphism of CYP11B2 predicts increased aldosterone to renin ratio in selected hypertensive patients

Altered control of aldosterone synthase (CYP11B2) gene expression may modulate aldosterone secretion, as suggested by a raised aldosterone to renin ratio (ARR) in some patients with essential hypertension. We compared the frequency of two linked CYP11B2 polymorphisms, one in the steroidogenic factor-1 (SF-1) binding site and the other an intronic conversion (Int2) in relation to ARR in 141 hypertensive patients. Patients were divided into groups with either normal or high supine ARR using a cut-off threshold of 145 pmol/liter per ng/liter. Supine ARR was normal in 104 patients and raised in 37 patients. The two polymorphisms were in strong linkage disequilibrium (chi(2) = 123.8; P < 0.0001). The SF-1 T and Int2 C alleles were more prevalent among patients with high ARR (46% and 43%, respectively) than with normal ARR (22% and 17%; P < 0.01 and P < 0.005, respectively). Odds ratios for raised ARR in subjects with a homozygous SF-1 T and Int2 C haplotype were 6.1 (95% confidence interval, 1.6-22.5; P < 0.005) when compared with the contrasting haplotype. Linear modeling of individual postural changes in renin and aldosterone showed a maximal achievable aldosterone increase of 110 pmol/liter with no mutated haplotype and 500 pmol/liter with two mutated haplotypes. These findings support the view of a molecular basis regulating aldosterone production.

Development and characterization of an animal model of carnitine deficiency

Mammals cover their carnitine needs by diet and biosynthesis. The last step of carnitine biosynthesis is the conversion of butyrobetaine to carnitine by butyrobetaine hydroxylase. We investigated the effect of N-trimethyl-hydrazine-3-propionate (THP), a butyrobetaine analogue, on butyrobetaine hydroxylase kinetics, and carnitine biosynthesis and body homeostasis in rats fed a casein-based or a vegetarian diet. The K(m )of butyrobetaine hydroxylase purified from rat liver was 41 +/- 9 micromol x L(-1) for butyrobetaine and 37 +/- 5 micromol x L(-1) for THP, and THP was a competitive inhibitor of butyrobetaine hydroxylase (K(i) 16 +/- 2 micromol x L(-1)). In rats fed a vegetarian diet, renal excretion of total carnitine was increased by THP (20 mg.100 g(-1) x day(-1) for three weeks), averaging 96 +/- 36 and 5.3 +/- 1.2 micromol x day(-1) in THP-treated and control rats, respectively. After three weeks of treatment, the total carnitine plasma concentration (8.8 +/- 2.1 versus 52.8 +/- 11.4 micromol x L(-1)) and tissue levels were decreased in THP-treated rats (liver 0.19 +/- 0.03 versus 0.59 +/- 0.08 and muscle 0.24 +/- 0.04 versus 1.07 +/- 0.13 micromol x g(-1)). Carnitine biosynthesis was blocked in THP-treated rats (-0.22 +/- 0.13 versus 0.57 +/- 0.21 micromol x 100 g(-1) x day(-1)). Similar results were obtained in rats treated with the casein-based diet. THP inhibited carnitine transport by rat renal brush-border membrane vesicles competitively (K(i) 41 +/- 3 micromol x L(-1)). Palmitate metabolism in vivo was impaired in THP-treated rats and the livers showed mixed steatosis. Steady-state mRNA levels of the carnitine transporter rat OCTN2 were increased in THP-treated rats in skeletal muscle and small intestine. In conclusion, THP inhibits butyrobetaine hydroxylase competitively, blocks carnitine biosynthesis in vivo and interacts competitively with renal carnitine reabsorption. THP-treated rats develop systemic carnitine deficiency over three weeks and can therefore serve as an animal model for human carnitine deficiency.

Cost-effectiveness in ambulatory care: alternative approaches

By relating health care resources and their use to health outcomes, through a coherent macro resource allocation framework, one can examine the health care system for allocative efficiencies. In this article, costs and outcomes are analyzed in such a framework, scenarios for optimizing the use of health care resources--while still maintaining existing health outcomes--are explored, and the implications for ambulatory care are discussed. The research clearly shows that much can be done to make health care systems more efficient without jeopardizing health outcomes.

[Reliability of duplex sonography in non-quantitative determination of blood flow in comparison to inductive flow measurement--an in vitro study]

Using an experimental design permitting generation of a pulsatile "flow-velocity waveform" corresponding to the fetal aortic signal, the influence of measurement depth, the angle between the Doppler beam and the vessel, the high-pass filter and the extent of overlap between the "sample volume" and the vessel cross-section were studied in vitro. The Resistance Index showed the best relation to inductive flow measurement, which was defined as standard. Considering the conditions prevailing during clinical studies, good reliability is likely at angles of between 0 degrees and 60 degrees (120 degrees-180 degrees) over the entire range of measuring depths (4-13 cm) and when using 100-200 Hz high-pass filters. The magnitude and location of the sample volume does not seem to play a decisive role provided a part of it is within the sonographically imaged "vessel" and there is no likelihood of interference from vessels in the immediate vicinity in which blood flow is in the same direction.

[Significance of the examination position in urodynamic assessment of female urinary incontinence]

The present paper describes a test center which permits urodynamics tests with the patient in various positions, such as lithotomy position (A), supine position with outstretched legs (B) and, by continuously raising the patient, upright position (C). The results of a comparative investigation show the influence of these different examination positions on urodynamic parameters, in particular the functional length of the urethra and maximum urethra closing pressure at rest. Urodynamic tests on 40 patients with urinary incontinence showed that there is a significant increase in the functional length of the urethra when the patient is in lithotomy position (A) as compared to lying with outstretched legs (B), and that it is once again significantly reduced when the patient is raised to upright position. Maximum urethra closing pressure at rest drops significantly when the patient is repositioned from lithotomy (A) to supine (B) position, and once again rises significantly when she is raised to the upright (C) as compared to the supine (B) position. In the light of the changes described, which cause major changes in the form of the urethra pressure profile, it makes sense to perform urodynamic measurements in at least two different positions. The authors recommend the supine position with outstretched legs (B), as it appears more physiological than the lithotomy position (A), and measurement in the upright position (C). The importance of positioning with regard to the diagnostic information value in determining the cause of urinary incontinence is discussed.

Continuous and simultaneous monitoring of EEG spectra and brainstem auditory and somatosensory evoked potentials in the intensive care unit and the operating room

Individual monitoring of EEG and evoked potentials is gradually becoming standard in neurosurgery: compressed power spectra during carotid endarterectomy, brainstem auditory evoked potentials (BAEP) during posterior fossa surgery, and somatosensory evoked potentials (SEP) mainly during spinal cord surgery. In this paper, a new technique is described in which EEG, BAEP, and SEP are recorded and evaluated simultaneously and continuously. This allows a better survey of different neuronal structures and systems in the brain and brainstem. First results from intraoperative and intensive care patient monitoring are reported.

[Controlled acoustic and photic stimulation of the fetus in the last pregnancy trimester]

The aim of the study communicated here was to check any fetal reactions occurring after external stimulation (light-optic and acoustic stimuli), depending on fetal behavioral status. The group studied (acoustic/light stimulation) comprised 85 patients with normal course of pregnancy at term (37th to 42nd week of gestation). They were compared with a control group of nonstimulated patients (n = 26), also with normal course of pregnancy and corresponding gestational age. Fetal heart frequencies and an external tokogram were recorded synchronously with the fetal respiration, body, limb and eye movements registered simultaneously by two independent observers and the fetal behavioral statuses were defined (Nijhuis, Prechtl et al. 1982; Boos and Schmidt 1984; van Vliet et al. 1985). The stimulation methods used were as follows: 1. Single-frequency pure tone (2 kHz, 120 dB, 5 sec) 2. Sawtooth-modulated pure tone (0.5-2.0 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 3. Low-frequency, sawtooth-modulated pure tone (with vibration effect), (0.1-0.3 kHz, modulation frequency 10 Hz, 120 dB, 5 sec) 4. Light stimulation: electronic photographic flash, luminous intensity 25 X 10(6) Lux/10(-3) sec, 8 flash sequences in 10 sec, distance from maternal abdomen 20 cm. In order to rule out purely coincidental changes in fetal attitude, both genuine and "sham" stimulations were performed in randomized sequence, in the latter case without any acoustic or light-optic signals. No differences in fetal reactions were found with the three different acoustic stimulation methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetal behavioural states and controlled sound stimulation

The aim of this study was to investigate responses of human fetuses near term (37-42 wks) (increase/decrease of fetal heart rate and/or fetal motility) to acoustic stimuli. The study group consisted of 43 patients and the control group of 27 patients. Polygraphic recordings of 5 different fetal variables were carried out synchronously for the categorization of the actual fetal behavioural state according to Nijhuis et al. (Nijhuis, J.G., Prechtl, H.F.R., Martin, C.B., Jr. and Bots, R.S.A.M. (1982): Early Hum. Dev., 6, 177-195). Controlled acoustic stimulation was performed either with sine wave tone (2 kHz, 120 dB and 5 s duration) or modulated sine wave tone (0.5-2 kHz, 'sawtooth' modulation, 120 dB and 5 s duration). An additional group of patients received 'sham' stimulation. Overall 84 acoustic stimulations have been carried out. In 26 out of 84 stimulations (30%) a fetal response could be observed within 5 s after acoustic stimulation. In general, there were far fewer fetal responses in sleep states than in states of wakefulness. Whereas in state 1 F only 1 out of 28 acoustic stimulations was followed by an immediate fetal response, more responses were observed in state 2 F. An obvious increase in fetal reactivity to acoustic stimulation was noted in states of wakefulness (states 3 F and 4 F). Comparison between the true and sham stimulations revealed a relatively high level of spontaneous fetal activity (high variation of fetal heart rate and fetal motility) present in states 2 F and 4 F. This must be taken into account in all assessments of fetal responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Transfusion reactions in cats due to AB blood group incompatibility

Blood transfusion reactions were investigated in 70 unsensitised and sensitised cats. Twenty-five compatible transfusions with respect to the AB blood group system did not result in any immediate transfusion reactions. Transfusion of B erythrocytes in 12 group A cats did not produce any severe reactions because of low anti-B titres in the A recipients. However, 30 of 50 group B cats (60 per cent) suffered severe shock reactions, characterised by marked hypotension, cessation of respiration and sometimes atrio-ventricular blocks, within two minutes of the injection of incompatible A cells (phase 1). From 35 seconds to five minutes later, markedly elevated blood pressures and extrasystoles were recorded (phase 2). The blood pressures generally stabilised within 30 minutes. Haemoconcentration and leucopenia were observed in severely reacting cats and leucopenia was also recorded in some A cats who received incompatible cells but did not exhibit transfusion reactions.

[Results and experiences with an autocorrelating ultrasonic cardiotocograph]

We present the results and experiences with a prototype cardiotocograph with US-autocorrelation processing. As this method is fundamentally different from conventional signal processing we are entering into the particular problems of this new FHR-technology. A total of 70 antepartum fetal rate recording from 53 patients and 38 intrapartum CTGs were evaluated. The antepartum results were excellent, the application time could be minimized and the quality of the recordings has been essentially improved. With the intrapartum recordings a computer comparison of long and short time irregularity of FHR derived from US-autocorrelation and direct fetal EKG was performed. The results proofed an excellent approximation to beat-to beat recording using the US-autocorrelation technique. The idea of using the new method intrapartum instead of invasive CTG could not be realised. This was due to a increasing loss of signal with progress of labor. To exclude maternal HR interferences the new monitor is supposed to record maternal heart rate simultaneously to FHR.

The influence of skull defects and reperfusion after extra-intracranial arterial bypass surgery on the sensorimotor EEG rhythm

Twelve patients with small burr hole skull defects after extra-intracranial arterial bypass surgery were studied. The amplitude and frequency of the sensorimotor rhythm were measured 7 days and 1, 2, 4, and 6 months after surgery in follow-up EEGs from the central region. Seven patients showed a frequency decrease (compared with preoperative measurement) on the operated side 7 days and/or 1 month after surgery. There was no case of frequency decrease 6 months after surgery; four patients displayed a late frequency increase. Ipsilateral amplitude enhancement was never found 7 days postoperatively, but after 6 months in nine patients. Such physical factors as burr holes and bone replacement can only partially explain the amplitude enhancement, and cannot explain the frequency decrease. It may be assumed that temporary clamping of the middle cerebral artery and/or reperfusion of an ischaemic area result in a brief deterioration of brain function, as indicated by frequency slowing and delayed amplitude enhancement; related observations were made in patients with cerebrovascular disorders and mild to moderate neurological deficit about 20 days after the onset and correlated with clinical recovery.

Blood transfusion reactions in the cat

The transfusion of only 4 ml of group A blood resulted in sudden death of a cat that was recovering from surgery. The clinical signs were similar in many respects to those exhibited by tranquilized group B cats when challenge exposed for the 1st time with incompatible A cells. The distribution of the A and B blood group antigens and the occurrence of naturally occurring isoantibodies in the cat were considered in relation to the probability of producing transfusion reactions. The results obtained with tranquilized and anesthetized cats demonstrated that immediate reactions can occur following the 1st transfusion of incompatible red blood cells. Cross matching with respect to the AB system is recommended before giving blood transfusions to cats.

A contribution to the monitoring of fetal arrhythmias

Antepartum and intrapartum monitoring problems are discussed with reference to a case history of a fetal AV-block detected during the 36th week of pregnancy. CTG instruments where the internal logic criteria can be turned off are suitable for monitoring arrhythmias. During labor the direct fetal ECG permits exact diagnosis as to the type of arrhythmia. The necessity of antepartum diagnosis in regard to postpartum pediatric management and hypoxic states during labor justify the large expenditure on monitoring apparatus. During labor continuous tissue pH measurement via the fetal scalp give added information as to fetal condition.

[A new oxytocin infusion rate recorder (author's transl)]

A new oxytocin-infusion rate recorder system is introduced. It provides continuous plotting dosages on the labor channel of the cardiotocogram. So far 82 conductions of labour were monitored with the new system and evaluated for oxytocin overstimulation. The rate of overstimulations could be reduced resulting in better fetal outcome.

Cerebral venous pressure during actively induced hypertension and hypercapnia in cats

Superior sagittal sinus pressure, intracranial pressure and arterial pressure were recorded in an experimental series on 10 cats. During drug-induced, severe, acute arterial hypertension and parallel hypercapnia, venous pressure could exceed intracranial pressure in both the supra- and infratentorial compartment. From these data it is concluded that cerebral venous pressure during acute arterial hypertension may contribute to protein extravasation at the postcapillary-venular level.

Medical versus surgical treatment of patients with cerebrovascular insufficiency. A retrospective comparative study

Report on a series of patients suffering from cerebrovascular insufficiency caused by stenosis and/or occlusion of one or several major cerebral vessels. The patients were divided in two groups, one being medically treated with anticoagulants, the other operated on either a carotid artery thrombosis by thromboendarterectomy or occlusion treated with an extracranial-intracranial arterial bypass. Results after a follow-up period of 1-3 years are compared and discussed in view of the recent literature.

Pial arteriolar reaction to intravenous administration of bencyclane in the cat

In a series of 29 experiments in cats, the vasodilatory effect of Bencyclane on pial arterioles was investigated by means of the cranial window technique, using an image-splitting eyepiece, a photometric method or simple microscopic observation. Intravenous injection of 3 mg kg-1 led to vasodilatation in all experiments, yet decreased blood pressure within 30--40 sec until 5--6 min down to 70% of resting pressure. Mean maximal dilatation of arterioles with a 76-micrometers mean resting diameter was 53%. After normalization of blood pressure, arteriolar diameters remained increased by 5--10% for further 10 min, thus indicating increased cerebral blood flow for a total time of about 15 min. During intravenous infusion of 0.2--0.3 mg kg-1min-1 of the drug, pial arterioles dilated by about 10% with blood pressure remaining on resting levels. A higher dosage rate of infusion evoked further vasodilatation, yet parallel decrease of blood pressure.

[Therapy of traumatic brain edema with spironolactone (author's transl)]

In 30 patients with severe brain injury a double-blind study was performed. The effectiveness of the aldosterone-antagonist Aldactone pro injectione was examined in therapy of traumatic brain edema. The results indicate elimination of sodium and water from brain cells and white matter. Concomitantly faster improvement of state of consciousness was observed.

Brain protease activity after experimental head injury

In an experimental series on twelve cats, activity changes of brain cell proteolytic activity were measured two hours after a blunt head injury without hematoma or contusions. Protease activity was estimated in two different brain tissue homogenate supernatants containing total soluble and only cytoplasmic activity without proteases in cell organelles, respectively. Total activity was doubled two hours after injury in the acid and the neural pH-range, in comparison to control values. Free soluble activity was doubled in the acid and increased to the threefold value in the neutral range. From these data, it seems that two different changes appear in lysosomes, the enzyme-reservoir of the cell: (1) Enzyme-synthesis is increased after trauma, measured as augmentation of total soluble protease activity in our experiments; (2) Breakage or increased permeability of lysosomes lead to augmentation of especially neutral proteases in the cytoplasm followed by the well known autolytic areas of generalized traumatic brain edema.

Azotaemia in severe head injury--central dysregulation or renal failure?

We have investigated serum urea, uric acid, and creatinin crealinine levels in 39 patients with craniocerebral trauma. The most impressive observation was a change in serum urea, which was found significantly increased up to 237 mg% on the seventh day (mean value) after severe injury, and turned out to be of great prognostic value. Patients with a serum urea above 100 mg% did not survive the acute stage. Uric acid and creatinine were only significantly increased in patients with lethal outcomes, the first being elevated by about 300% in the first week, the second remaining normal for four days increasing thereafter. It is concluded from these first data that a hypercatabolic state due to shock, central dysregulation, or both, is responsible for the dissociated behaviour of urea, uric acid and creatinine during the first four days, after which renal failure as a secondary change is shown by the rise in serum creatinine.

[Controlled hypotension with sodium nitroprusside in neurosurgical patients (author's transl)]

Sodium Nitroprusside (Nipride) was administered by infusion pump intravenously in 27 neurosurgical patients for intraoperative, postoperative and posttraumatic blood pressure lowering. This was accomplished with intension to reduce the risk of hemorrhage during operation on highly vascularized tumors or aneurysms and to combat hypertensive crisis after surgery and brain injury. The effect was documented by direct arterial blood pressure registration and the drug proved to be fast acting, potent and readily reversible. Dosage varied between 1 and 10 microgram/kg/min with systolic pressure decreasing about 6 to 60% of the initial value. There was ill correlation between infusion rate and blood pressure drop which demanded particular caution at the beginning and the end of infusion. A decrease in pulse pressure and a moderate tachycardia were generally observed, however no complications were seen due to a Sodium Nitroprusside administration over less than 12 hours duration in our series.

[Sodiumnitroprusside in neurosurgery and intensive care of neurosurgical patients (author's transl)]

Sodium nitroprusside (Nipride) was used in 35 patients between 16 and 72 years for induced hypotension. The fast and dose-dependent effect on the smooth muscles of the vessels made it superior to other methods of lowering blood pressure. Sodium nitroprusside was used to achieve hypotension in 11 patients (group I) with an aneurysm of a cerebral vessel and in 16 patients (group II) with highly vascularized cerebral tumors. In 8 patients (group III) from the neurosurgical intensive care unit a hypertensive crisis was interrupted. 10 patients (group IV) without induced hypotension were used as controls to compare the action of our standardized method of anesthesia on the observed parameters of blood pressure lowering. The average dose of sodium nitroprusside was 2.74 mcg/kg/min. in group I, 1.77 mcg/kg/min in group II and 1.27 mcg/kg/min in group III. The initial blood pressure was lowered between 30--40% in the mean in all 3 groups. Careful monitoring of the intra-arterial blood pressure, the central venous pressure, the cerebral fluid pressure, the arterial blood gases and the function of the kidneys during and after induced hypotension with sodium nitroprusside made it possible to take advantage of the blood pressure lowering effect also in patients with increased intracranial pressure.

Serum haptoglobulin changes in patients with severe isolated head injury

From a series of 74 patients with severe head injuries and massive brain lesions, we measured the changes in haptoglobulin in 33 cases. On average, the globulin was, after a short drop in the first two days, increased about three times towards the seventh day, and was still above normal after ten days. Seen together with the total alpha-2-globulin increase after head injury this rise seems mainly to be caused by the haptoglobulin changes. Haptoglobulin was found to be a good indicator of the extent of brain tissue damage. It cannot on its own be used for prediction of survival chances.

The action of sodium nitroprusside on the pial vessels

This study in cats investigates the action of sodium nitroprusside on the pial vessels by systemic and local administration, with an intravital microscopic window technique and a photometric technique for graphic documentation of vessel diameter changes. Intravenous infusion caused vasodilatation parallel with decreasing blood pressure. Pial arterioles dilated more than venules, smaller vessels more than larger ones. Local administration caused maximal dilatation within 5--10 seconds. With blood pressure returning to normal after i.v. therapy, pial vessels remained wider than they were before hypotension at the same pressure level. From these data it is concluded that the substance acts longer on the brain vessels than on vessels elsewhere in the body, and that cerebrovascular autoregulation to blood pressure changes is disturbed during this period.