Protocol to isolate nuclei from Chlamydomonas reinhardtii for ATAC sequencing

The isolation of sufficient amounts of intact nuclei is essential to obtain high-resolution maps of chromatin accessibility via assay for transposase-accessible chromatin using sequencing (ATAC-seq). Here, we present a protocol for tag-free isolation of nuclei from both cell walled and cell wall-deficient strains of the green model alga Chlamydomonas reinhardtii at a suitable quality for ATAC-seq. We describe steps for nuclei isolation, quantification, and downstream ATAC-seq. This protocol is optimized to shorten the time of isolation and quantification of nuclei.

Conserved cobalamin acquisition protein 1 is essential for vitamin B12 uptake in both Chlamydomonas and Phaeodactylum

Microalgae play an essential role in global net primary productivity and global biogeochemical cycling. Despite their phototrophic lifestyle, over half of algal species depend for growth on acquiring an external supply of the corrinoid vitamin B12 (cobalamin), a micronutrient produced only by a subset of prokaryotic organisms. Previous studies have identified protein components involved in vitamin B12 uptake in bacterial species and humans. However, little is known about its uptake in algae. Here, we demonstrate the essential role of a protein, cobalamin acquisition protein 1 (CBA1), in B12 uptake in Phaeodactylum tricornutum using CRISPR-Cas9 to generate targeted knockouts and in Chlamydomonas reinhardtii by insertional mutagenesis. In both cases, CBA1 knockout lines could not take up exogenous vitamin B12. Complementation of the C. reinhardtii mutants with the wild-type CBA1 gene restored B12 uptake, and regulation of CBA1 expression via a riboswitch element enabled control of the phenotype. When visualized by confocal microscopy, a YFP-fusion with C. reinhardtii CBA1 showed association with membranes. Bioinformatics analysis found that CBA1-like sequences are present in all major eukaryotic phyla. In algal taxa, the majority that encoded CBA1 also had genes for B12-dependent enzymes, suggesting CBA1 plays a conserved role. Our results thus provide insight into the molecular basis of algal B12 acquisition, a process that likely underpins many interactions in aquatic microbial communities.

The importance of vitamin B12 for individuals choosing plant-based diets

Vitamin B₁₂ is an essential nutrient that is not made by plants; consequently, unfortified plant-based foods are not a reliable supply. Recent estimates suggest high rates of vitamin B₁₂ deficiency among the vegetarian and vegan populations, particularly in pregnant women or women of child-bearing age who, for ethical and health reasons, are shifting towards higher consumption of plant-based foods in ever-increasing numbers. Vitamin B₁₂ plays crucial metabolic roles across the life-course and in particular during pregnancy and in early development (first 1000 days of life). Evidence now implicates vitamin B₁₂ deficiency with increased risk to a range of neuro, vascular, immune, and inflammatory disorders. However, the current UK recommended nutrient intake for vitamin B₁₂ does not adequately consider the vitamin B₁₂ deficit for those choosing a plant-based diet, including vegetarianism and in particular veganism, representing a hidden hunger. We provide a cautionary note on the importance of preventing vitamin B₁₂ deficits for those individuals choosing a plant-based diet and the health professionals advising them.

Thiamine metabolism genes in diatoms are not regulated by thiamine despite the presence of predicted riboswitches

Thiamine pyrophosphate (TPP), an essential co-factor for all species, is biosynthesised through a metabolically expensive pathway regulated by TPP riboswitches in bacteria, fungi, plants and green algae. Diatoms are microalgae responsible for c. 20% of global primary production. They have been predicted to contain TPP aptamers in the 3'UTR of some thiamine metabolism-related genes, but little information is known about their function and regulation. We used bioinformatics, antimetabolite growth assays, RT-qPCR, targeted mutagenesis and reporter constructs to test whether the predicted TPP riboswitches respond to thiamine supplementation in diatoms. Gene editing was used to investigate the functions of the genes with associated TPP riboswitches in Phaeodactylum tricornutum. We found that thiamine-related genes with putative TPP aptamers are not responsive to supplementation with thiamine or its precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP), and targeted mutation of the TPP aptamer in the THIC gene encoding HMP-P synthase does not deregulate thiamine biosynthesis in P. tricornutum. Through genome editing we established that PtTHIC is essential for thiamine biosynthesis and another gene, PtSSSP, is necessary for thiamine uptake. Our results highlight the importance of experimentally testing bioinformatic aptamer predictions and provide new insights into the thiamine metabolism shaping the structure of marine microbial communities with global biogeochemical importance.

Exploring the Impact of Terminators on Transgene Expression in Chlamydomonas reinhardtii with a Synthetic Biology Approach

Chlamydomonas reinhardtii has many attractive features for use as a model organism for both fundamental studies and as a biotechnological platform. Nonetheless, despite the many molecular tools and resources that have been developed, there are challenges for its successful engineering, in particular to obtain reproducible and high levels of transgene expression. Here we describe a synthetic biology approach to screen several hundred independent transformants using standardised parts to explore different parameters that might affect transgene expression. We focused on terminators and, using a standardised workflow and quantitative outputs, tested 9 different elements representing three different size classes of native terminators to determine their ability to support high level expression of a GFP reporter gene. We found that the optimal size reflected the median size of element found in the C. reinhardtii genome. The behaviour of the terminator parts was similar with different promoters, in different host strains and with different transgenes. This approach is applicable to the systematic testing of other genetic elements, facilitating comparison to determine optimal transgene design.

Freshwater monitoring by nanopore sequencing

While traditional microbiological freshwater tests focus on the detection of specific bacterial indicator species, including pathogens, direct tracing of all aquatic DNA through metagenomics poses a profound alternative. Yet, in situ metagenomic water surveys face substantial challenges in cost and logistics. Here, we present a simple, fast, cost-effective and remotely accessible freshwater diagnostics workflow centred around the portable nanopore sequencing technology. Using defined compositions and spatiotemporal microbiota from surface water of an example river in Cambridge (UK), we provide optimised experimental and bioinformatics guidelines, including a benchmark with twelve taxonomic classification tools for nanopore sequences. We find that nanopore metagenomics can depict the hydrological core microbiome and fine temporal gradients in line with complementary physicochemical measurements. In a public health context, these data feature relevant sewage signals and pathogen maps at species level resolution. We anticipate that this framework will gather momentum for new environmental monitoring initiatives using portable devices.

Responses of a Newly Evolved Auxotroph of Chlamydomonas to B12 Deprivation

The corrinoid B₁₂ is synthesized only by prokaryotes yet is widely required by eukaryotes as an enzyme cofactor. Microalgae have evolved B₁₂ dependence on multiple occasions, and we previously demonstrated that experimental evolution of the non-B₁₂-requiring alga Chlamydomonas reinhardtii in media supplemented with B₁₂ generated a B₁₂-dependent mutant (hereafter metE7). This clone provides a unique opportunity to study the physiology of a nascent B₁₂ auxotroph. Our analyses demonstrate that B₁₂ deprivation of metE7 disrupts C1 metabolism, causes an accumulation of starch and triacylglycerides, and leads to a decrease in photosynthetic pigments, proteins, and free amino acids. B₁₂ deprivation also caused a substantial increase in reactive oxygen species, which preceded rapid cell death. Survival could be improved without compromising growth by simultaneously depriving the cells of nitrogen, suggesting a type of cross protection. Significantly, we found further improvements in survival under B₁₂ limitation and an increase in B₁₂ use efficiency after metE7 underwent a further period of experimental evolution, this time in coculture with a B₁₂-producing bacterium. Therefore, although an early B₁₂-dependent alga would likely be poorly adapted to coping with B₁₂ deprivation, association with B₁₂-producers can ensure long-term survival whilst also providing a suitable environment for evolving mechanisms to tolerate B₁₂ limitation better.

Cyanobacteria and Eukaryotic Algae Use Different Chemical Variants of Vitamin B12

Eukaryotic microalgae and prokaryotic cyanobacteria are the major components of the phytoplankton. Determining factors that govern growth of these primary producers, and how they interact, is therefore essential to understanding aquatic ecosystem productivity. Over half of microalgal species representing marine and freshwater habitats require for growth the corrinoid cofactor B₁₂, which is synthesized de novo only by certain prokaryotes, including the majority of cyanobacteria. There are several chemical variants of B₁₂, which are not necessarily functionally interchangeable. Cobalamin, the form bioavailable to humans, has as its lower axial ligand 5,6-dimethylbenzimidazole (DMB). Here, we show that the abundant marine cyanobacterium Synechococcus synthesizes only pseudocobalamin, in which the lower axial ligand is adenine. Moreover, bioinformatic searches of over 100 sequenced cyanobacterial genomes for B₁₂ biosynthesis genes, including those involved in nucleotide loop assembly, suggest this is the form synthesized by cyanobacteria more broadly. We further demonstrate that pseudocobalamin is several orders of magnitude less bioavailable than cobalamin to several B₁₂-dependent microalgae representing diverse lineages. This indicates that the two major phytoplankton groups use a different B₁₂ currency. However, in an intriguing twist, some microalgal species can use pseudocobalamin if DMB is provided, suggesting that they are able to remodel the cofactor, whereas Synechococcus cannot. This species-specific attribute implicates algal remodelers as novel and keystone players of the B₁₂ cycle, transforming our perception of the dynamics and complexity of the flux of this nutrient in aquatic ecosystems.

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Dominant marine cyanobacteria synthesize only pseudocobalamin

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Pseudocobalamin is orders of magnitude less bioavailable to eukaryotic algae

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Certain algae can remodel pseudocobalamin to a bioavailable form

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This implies a complex B₁₂ cycle between microbes in the photic zone

[Results of hearing screenings in 14- to 15-year old adolescents]

BACKGROUND

A hearing screening among 14- to 15-year-old pupils was performed to estimate the number of hearing-impaired individuals in the adolescent population.

MATERIALS AND METHODS

A total of 1,298 pupils from 30 schools in Tyrol (Austria) participated in the screening. Hearing tests were performed in a silent room at the school. Sinus tones at frequencies 0.5/1/2/4/6 kHz and at levels of 25/20/20/20/20 dB HL, respectively, were delivered via headphones to either ear. Failure of screening was defined as not hearing one or more frequencies in one or both ears.

RESULTS

The screening was failed by 16.3% of the pupils. There was a small but not significant difference between males and females (17.0 vs. 15.2%). Most of the pupils failed at only one frequency (9.6%). Failing at two or more frequencies in the same ear occurred in 3.9% of the pupils, thereof in 1.1% bilaterally.

CONCLUSION

As the specificity of our screening is limited, false-positive results may result. Thus, the rate of hearing deficits in our sample is probably a bit lower than indicated by the figures above. Most of the adolescents who failed the screen failed at only one frequency. These subjects have a small elevation of their hearing threshold, not a hearing loss in the sense of a raised averaged threshold. A hearing loss in the latter sense is supposed to be present in only very few percent of adolescents, a bilateral hearing loss in perhaps less than 1%.

Auricular acupuncture for postoperative pain after gynecological surgery: a randomized controlled trail

BACKGROUND

Acupuncture for postoperative pain remains controversial. Potential sources of bias are failures in patient-blinding and therapist-patient interactions. Our study investigates the effects of electrical auricular acupuncture (AA) on postoperative pain in patients undergoing laparoscopy with an emphasis on patient-blinding and the exclusion of therapist-patient interactions.

METHODS

With institutional review board approval and written informed consent, we included 40 female patients undergoing laparoscopy. Patients were randomly assigned to receive AA (shen men, thalamus and one segmental organ-specific point) or electrodes only and an electrical stimulation device. All patients received this intervention under general anesthesia guaranteeing patient blinding and excluding therapist-patient interactions. Needles and devices were removed 72 hours postoperatively. Postoperatively, patients received 1,000 mg paracetamol every 6 hours. Additional piritramide was given on demand. A blinded observer obtained the VAS scores at 0, 2, 24, 48, and 72 hours as well as the postoperatively administered doses of piritramide.

RESULTS

There was no difference in VAS scores or the consumption of piritramide during the first 72 hours postoperatively between groups (acupuncture versus placebo: 2.32 [1.40-3.25] versus 2.62 [1.89-3.36] average pain on VAS 0-10; 15.3 [12.0-18.6] mg versus 13.9 [10.5-17.3] mg piritramide). Values are expressed as mean [CI].

CONCLUSION

Our study shows no reduction in postoperative pain or an opioid sparing effect of auricular acupuncture in women undergoing laparoscopic procedures. Because we emphasized blinding of the patients and the exclusion of therapist-patient interactions, our study suggests that electrical auricular acupuncture has no effect on postoperative pain.

Laparoscopic Versus Open Myomectomy: A Double-Blind Study to Evaluate Postoperative Pain

The advantages of laparoscopic over open surgery have been documented in nonblinded settings. Our prospective, double-blind setting evaluated pain scores 72 h after surgery by comparing patients who underwent laparoscopic myomectomy or with laparotomy. Forty women referred for conservative myomectomy were included in the study. After stratification (myoma size, number of myomas, and surgeon), patients were randomized to either laparoscopy (n = 19) or laparotomy (n = 21) and received a standardized anesthesia and patient-controlled analgesia for 24 h after surgery. Identical wound dressings were applied to blind the patient and the observer to the surgical approach. The postoperative pain scores were documented on a visual analog scale (VAS; 0 = no and 10 = unbearable pain) at 24, 48, and 72 h after surgery. As the primary outcome variable, we calculated the mean overall VAS-score at these time points. P < 0.05 (t-test and analysis of covariance) was considered statistically significant. There were no differences in patient characteristics among the groups. The mean overall VAS score at 24, 48, and 72 h was statistically significantly lower in the laparoscopic group compared with the laparotomy group (2.28 +/- 1.38 versus 4.03 +/- 1.63; P < 0.01). Our data demonstrate, for the first time in a double-blind setting, that laparoscopic myomectomy reduces postoperative pain for 72 h after surgery compared with laparotomy.

The effect of graded hypothermia (36 degrees C-32 degrees C) on hemostasis in anesthetized patients without surgical trauma

The isolated effects of hypothermia on hemostasis have not been investigated in healthy humans. We cooled 16 anesthetized patients scheduled for elective intracranial surgery to 32 degrees C body core temperature and assessed prothrombin time (PT), activated partial thromboplastin time, thrombelastogram (TEG), closure time, and platelet count at 36 degrees C, 34 degrees C, and 32 degrees C body core temperature after the induction of anesthesia but before surgical intervention. Activated partial thromboplastin time, hematocrit, and closure time did not change, whereas PT and platelet count decreased during cooling. Platelet count decreased without a decrease in hematocrit; hence, a dilution by administered fluids seemed unlikely. The small decrease of platelet count is probably clinically irrelevant in patients with normal platelet count and function. The small decrease in PT indicates an alteration of the extrinsic pathway of coagulation. TEG measurements showed a delay of clot formation in temperature-adjusted measurements but showed no change if the test temperature was 37 degrees C. This indicates that hypothermia reduces plasmatic coagulation and platelet reactivity. However, the clot strength is not altered by hypothermia. All coagulation variables remained within the normal ranges. Our results may indicate that moderate short-term (4-h) hypothermia has only minor adverse effects in healthy humans. We can make no statement about the effects of hypothermia of longer duration.

IMPLICATIONS

This study investigated the isolated effects of hypothermia in healthy anesthetized humans. We found only minor effects of body temperature reduction to 32 degrees C on assessed coagulation variables, indicating only minor effects in otherwise healthy humans.

Recollection of dreams after short general anaesthesia: influence on patient anxiety and satisfaction

BACKGROUND AND OBJECTIVE

We ascertained whether dreams during short general anaesthesia influence subsequent patient satisfaction and anxiety.

METHODS

Fifty female patients were randomized into two groups to test for a difference between intravenous and inhalational anaesthesias. In Group Propo, anaesthesia was induced and maintained with propofol; in Group Metho-Iso, anaesthesia was induced with methohexital and maintained with isoflurane. Satisfaction and anxiety with anaesthesia were evaluated using a visual analogue scale from 0 to 100. Dream incidence rate, satisfaction and anxiety were assessed from immediately after waking until 3 months later.

RESULTS

Seventeen patients (34%) dreamed during anaesthesia. There were no significant differences in satisfaction or anxiety after anaesthesia between the dreaming and non-dreaming patients (satisfaction, 92.3 +/- 21.6 versus 92.1 +/- 21.6; anxiety, 21.1 +/- 21.1 versus 30.3 +/- 32.1), or between Group Propo and Group Metho-Iso (satisfaction, 94.4 +/- 19.3 versus 90.0 +/- 23.4; anxiety, 26.0 +/- 27.6 versus 28.4 +/- 30.7). There was no significant difference in the incidence rate of dreaming with the type of anaesthesia used (Group Propo, 11 patients; Group Metho-Iso, 6 patients).

CONCLUSIONS

Dreaming during general anaesthesia is common but does not influence satisfaction or anxiety after anaesthesia.

A comparison of propofol and sevoflurane anaesthesia: effects on aortic blood flow velocity and middle cerebral artery blood flow velocity

We compared systemic (aortic) blood flow and cerebral blood flow velocity in 30 patients randomly allocated to receive either propofol or sevoflurane anaesthesia. Cerebral blood flow velocity (CBFv) was measured in the middle cerebral artery using transcranial Doppler. Systemic blood flow velocity (SBFv) was measured in the aorta using transthoracic Doppler sonography at the level of the aortic valve. Bispectral index (BIS) was used to measure the depth of anaesthesia. Measurements were made in the awake patient and repeated during propofol or sevoflurane anaesthesia, with BIS measurements of 40-50. The effects of SBFv on CBFv were estimated by calculating the cerebral/systemic blood flow velocity-index (CsvI). A CsvI value of 100 indicating a 1 : 1 relationship between CBFv and SBFv. The results demonstrated that propofol anaesthesia produced a significantly greater reduction in CsvI than did sevoflurane anaesthesia [propofol: 60 (19); sevoflurane: 83 (16), p = 0.009, t-test]. This suggests a direct reduction in CBFv independent of SBFv during propofol anaesthesia. The greater reduction of CBFv occurring during propofol anaesthesia may be due to lower cerebral metabolic demand compared with sevoflurane anaesthesia at comparable depths of anaesthesia.

Influence of aortic blood flow velocity on changes of middle cerebral artery blood flow velocity during isoflurane and sevoflurane anaesthesia

BACKGROUND AND OBJECTIVE

We studied the influence of systemic (aortic) blood flow velocity on changes of cerebral blood flow velocity under isoflurane or sevoflurane anaesthesia.

METHODS

Forty patients (age: isoflurane 24-62 years; sevoflurane 24-61 years; ASA I-III) requiring general anaesthesia undergoing routine spinal surgery were randomly assigned to either group. Cerebral blood flow velocity was measured in the middle cerebral artery by transcranial Doppler sonography (depth: 50-60 mm). Systemic blood flow velocity was determined by transthoracic Doppler sonography at the aortic valve. Heart rate, arterial pressure, arterial oxygen saturation and body temperature were monitored. After standardized anaesthesia induction (propofol, remifentanil, vecuronium) sevoflurane or isoflurane were used as single agent anaesthetics. Cerebral blood flow velocity and systemic blood flow velocity were measured in the awake patient (baseline) and repeated 5 min after reaching a steady state of inspiratory and end-expiratory concentrations of 0.75, 1.00, and 1.25 mean alveolar concentrations of either anaesthetic. To calculate the influence of systemic blood flow velocity on cerebral blood flow velocity, we defined the cerebral-systemic blood flow velocity index (CSvI). CSvI of 100% indicates a 1:1 relationship of changes of cerebral blood flow velocity and systemic blood flow velocity.

RESULTS

Isoflurane and sevoflurane reduced both cerebral blood flow velocity and systemic blood flow velocity. The CSvI decreased significantly at all three concentrations vs. 100% (isoflurane/sevoflurane: 0.75 MAC: 85 +/- 25%/81 +/- 23%, 1.0 MAC: 79 +/- 19%/74 +/- 16%, 1.25 MAC: 71 +/- 16%/79 +/- 21%; [mean +/- SD] P = 0.0001).

CONCLUSIONS

The reduction of the CSvI vs. 100% indicates a direct reduction of cerebral blood flow velocity caused by isoflurane/sevoflurane, independently of systemic blood flow velocity.

Gram staining and lectin binding properties of Myxosporea and Sporozoea

The staining method developed by Christian Gram was introduced as a simple and highly selective tool for demonstrating myxosporean and coccidian sporogonic stages. When using standard blood staining procedures for those enigmatic parasites it is sometimes difficult to distinguish them from fish host tissue. They clearly exhibit a partial gram-positive reaction in histological sections, but staining is variable in air dried fish organ imprints. To visualize the gram-negative background of different host tissue components in histological sections, the conventional safranin counterstain of the gram protocol may be modified as follows: after application of 2% crystal violet (basic violet 3) and Lugol's solution, sections are stained with 0.1% nuclear fast red-5% aluminum sulfate and 0.35% aniline blue (acid blue 22) dissolved in saturated aqueous picric acid. Replacement of the gram-specific dye crystal violet with 2% malachite green gave similar results in organ imprints containing myxospores or coccidia, but only in sections containing myxosporea. Staining for 1 min with an aqueous solution of 0.5% malachite green and followed 1 min washing was sufficient for rapidly demonstrating the parasite spores in organ imprints of both myxosores and oocysts. With regard to the role of acid mucopolysaccharides and other carbohydrates in the gram reaction of spores, alcian blue 8GX staining was compared to the binding of FITC-labeled WGA, GS I and GS II. Each lectin was applied at 20 microl/ml PBS, HEPES for 1 hr. Whereas WGA yielded a nonspecific pattern like the alcian blue staining, GS II resulted in a pattern similar to the gram staining results. This binding was weak in untreated specimens, but was significantly enhanced when digested first within trypsin overnight in a humid chamber at 37 degrees C. The binding of GS II to both myxosporidian and coccidian spores suggests that they are both composed of polymers containing N-acetyl-D-glucosamine residues. Furthermore, the results suggest that this hexosamine plays a key role in the gram reaction.

CTLA4Ig inhibits T cell-dependent B-cell maturation in murine systemic lupus erythematosus

Long-term administration of CTLA4Ig prevents the onset of disease in systemic lupus erythematosus-prone (SLE-prone) NZB/NZW F1 mice. To determine the mechanism of this effect, we engineered an adenovirus that expresses murine CTLA4Ig. Administration of a single high dose of this virus results in long-term expression of CTLA4Ig in the serum and absence of an immune response to the adenoviral vector. We administered Ad-CTLA4Ig to 19- to 22-week-old NZB/NZW F1 mice and evaluated the effect on anti-DNA antibody-producing B cells. We show that CTLA4Ig has a beneficial effect on murine SLE for as long as it is present in the serum. This effect is associated with decreased expansion of both the IgM and IgG autoreactive B-cell population, inhibition of immunoglobulin class switching, decreased frequency and altered pattern of somatic mutation, and a marked decrease in the numbers of activated CD4-positive T cells. In contrast, intrinsic B-cell hyperreactivity and the survival of plasma cells in the bone marrow, both of which are less dependent on T-cell help, appear to be unaffected by CTLA4Ig. High-dose CTLA4Ig did not induce permanent tolerance in this autoimmune disease model. Furthermore, although the mice survived in a conventional housing facility, treatment with Ad-CTLA4Ig was immunosuppressive.

Severe pneumothorax after intercostal nerve blockade. A case report

BACKGROUND

Intercostal nerve blockade is recognized as an efficient and safe regional anesthetic technique. Although an appropriate technique was applied, we report a severe pneumothorax associated with this type of regional anesthesia.

METHODS

A 57-year-old female patient underwent block of intercostal nerves 3 to 8 for interstitial radiotherapy of the left breast in the sitting position. Calcified residual foci in the right upper lobe from a previous primary infection of tuberculosis were diagnosed by preoperative x-ray. After completion of the blocks in the midline of the axilla, the patient complained of pain between the scapulas, developed severe dyspnea and panic, and felt as if her life was in jeopardy. A severe pneumothorax was diagnosed and a chest tube was placed. After the application of the chest tube, the patient recovered quickly.

CONCLUSION

Extra caution should be used in applying this procedure to patients with underlying chronic lung disease, especially on the opposite side. Our case demonstrates that in all patients undergoing intercostal nerve blockade preference should be given to the approach at the dorsal angulation of the rib in the lateral or prone position due to its lower risk of pneumothorax.

Improved laparoscopic operating techniques using a digital enhancement video system

We conducted a prospective, randomized trial in a piglet model to assess the advantages of a digital enhancement video system during difficult endoscopic procedures. Laparoscopic pelvic lymphadenectomy was performed with either conventional two-dimensional or digitally enhanced videoendoscopy. With equal amounts of extirpated lymph nodes, the operations performed with digitally enhanced videoendoscopy were significantly shorter (left lymphadenectomy p = 0.0001, right lymphadenectomy p = 0.001), had less blood loss and fewer false movements, and were associated with no complications, compared with those performed with a two-dimensional videosystem. Thus the accuracy of difficult laparoscopic techniques can be improved by three-dimensional visual perception.

[The effect of environmental factors on the occurrence of udder diseases]

The influence of housing factors on udder diseases was investigated in 2156 tiestall barns with 41893 cows and in 98 loose housed herds with 4126 cows. In loose housed herds less teat injuries were observed and also less mastitis than in tiestall barns. Within the different tiestall systems there was a trend to more udder diseases in short standings with a dung grid than in other systems. The ordinary neck chain and the "Grabner"-tethering system showed better results than the horizontal chain and the yoke tying system. Stall partitions between the cows caused a marked reduction of udder diseases. The installation of a cow trainer showed advantages regarding udder diseases. Inaccurate standing measurements (length and width) caused more udder diseases. When the metal grid was in poor condition, the incidence of teat injuries as well as udder diseases of heifers increased. Teat injuries and udder infections were more frequent when limb or digit injuries were found. Regular hoof care twice a year reduced the udder disease rate. Bedding material influenced the incidence of udder diseases positively. On farms where the cows were on pasture, the incidence of udder infections was higher than on farms where the cows were permanently housed. Heifers that were tied as calves or as juveniles showed significantly less udder diseases than those that were raised in groups. Faults in milking, defects in milking machines and deficits in milking hygiene showed a negative effect on udder diseases.

[Maternal and fetal metabolic parameters in acute and chronic fetal malnutrition]

The respiratory pathophysiology of placental insufficiency is well understood, whereas the metabolic effects of chronical or acute malnutrition still need further evaluation. In a comprehensive study of 20 deliveries respiratory parameters and substrates of carbohydrate- and lipid-metabolism were analysed simultaneously from maternal blood at 4 cm dilatation, at cord clamping immediately delivery and 2 hours post partum as well as from arterial and venous umbical blood samples. Normal deliveries were compared with cases of fetal retardation and moderate acute fetal acidosis. For glucose, insulin, c-peptide and pyruvate a strong rise in maternal blood during labour was observed as well as for the non-esterified fatty acids (NEFA), which have a high materno-fetal gradient. Arterio-venous differences of concentrations were found in the umbilical cord blood for glucose, pyruvate and NEFA. In cases of chronical insufficiency of the placenta especially elevated lactate levels were measured, whereas a moderate fetal acidosis obviously leads to an additional feto-maternal pyruvate transfer. The results lead to the conclusion that the fetal metabolism has considerable means of adaptation during delivery even under chronical or moderate acute stress conditions.

[Long-chain non-esterified fatty acids in pregnancy, labor and post partum]

Serum concentrations of non-esterified fatty acids (NEFA) remain unchanged up to the 21th week of gestation in comparison to non-pregnant women; also after the 37th gestational week only slightly increased concentrations are observed in women without labour. Under delivery, however, NEFA in maternal serum are approximately three times higher than those of non-pregnant women. This increase occurs only in NEFA with a chain-length of C12 to C18. Post partum values reach those of non-pregnant women within a few days. The concentrations of NEFA with a chain-length of C12 to C18 in umbilical artery and vein are significantly lower than in maternal serum.

The predictive value of behavioural risk factors for sudden infant death

In order to examine the predictive value of risk factors for the Sudden Infant Death Syndrome (SIDS), we have interviewed the parents of 80 SIDS victims and 80 parents of a healthy control group. From these interviews a list of 24 clinical and behavioural symptoms was assembled which appeared to be associated with the risk for SIDS. Out of this list of 24 symptoms the average number of symptoms reported to be observable in SIDS victims was twice as large as the average number of symptoms reported for healthy controls. The following symptoms appeared markedly more often in SIDS victims than in the controls: difficulties in awakening the baby, shrill crying, apathy, few movements during sleep, and cyanosis. We have attempted to consider a possible bias in the report of the parents of deceased infants by the introduction of an "exaggeration factor". By application of Bayes' theorem the highest predictive probability, 2.7%, was found for difficulties in awakening the baby. This is approximately nine times the assumed a priori probability of SIDS of 0.3%. We conclude that behavioural risk factors have a low but still remarkable predictive probability. A behavioural pattern of apathy and sleepiness indicates risk with a high probability.

[Pattern of distribution of apolipoproteins A and B in the lipoprotein fractions of serum in pregnant patients and post partum]

Investigating the for gestationally caused changes and their restitution p. partum we determined in 104 women without metabolic disorders the apolipoproteins A and B respectively in serum, in the main lipoprotein fractions VLDL, IDL, LDL, HDL and in the "rest protein" remaining after separation of the lipoproteins from the serum. In gestation there is an increase in the serum level of apo A of about 30% (p less than 0.001) reaching its maximum in the middle period of pregnancy. The post partal restitution of these changes takes more than 5 weeks happening faster at primarily delactated women. Gestational changes concerning apo A are only caused by a 30% higher concentration of apo A in HDL (p less than 0.001). The serum level of apo B seems to increase continuously meanwhile gestation reaching its maximum from about 60% (p less than 0.001) at the term. The restitution of the gestational changes concerning apo B also requires more than 5 weeks showing no dependence from lactation. The changes of serum apo B are quantitatively most influenced by the 45% higher concentration of apo B in LDL (p less than 0.001), despite the marked changes of apo B in relation to the nonpregnant comparative group found in VLDL and IDL respectively with either 270% (each p less than 0.001). Hyperbetalipoproteinemia in pregnancy was proved in 32%, but in no case the ratio apo B/apo A showed pathological values, because of also raised levels of apo A in these women. By this astonishing phenomenon the gestational hyperlipoproteinemia is characterized as an autonomic metabolic situation, which represents no earlier described type according to the Fredrickson classification.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aphasia--characteristics and therapeutic measures]

The Otorhinolaryngologist may need information about patients with central language disorders. Some behavioural features and intervention strategies are discussed for evaluating aphasic syndromes.

Determination of long-chain nonesterified fatty acids in sera of young women in different phases of the menstrual cycle. Application of a new gas chromatographic microliter method

Nonesterified fatty acids (NEFA) from C12 to C24 have been determined in sera of 13 young women at menstruation, and in the follicular and luteal phase of the menstrual cycle applying a new gas chromatographic microliter method. Neither the total NEFA content nor the concentrations of individual fatty acids showed significant differences in the three phases of the menstrual cycle. With the exception of stearic acid we found almost constant relative concentration values for the individual fatty acids within the medium range of the long-chain NEFA spectrum. Intraindividual and interindividual dispersion was hardly greater than the variation caused by the method of determination itself, whereas the intra- and interindividual scattering of the rim fractions of the NEFA spectrum was much more distinct. The coefficients of variation for the as well as individual NEFA content related to all examined women at any phase of the menstrual cycle were lower than 40% with the exception of the rare erucic acid, behenic acid and lignoceric acid.

A microliter method for the gas chromatographic determination of long-chain non-esterified fatty acids in human serum or plasma

Non-esterified fatty acids (NEFA) from C12 to C24 are assayed in human serum or plasma in a four-step procedure: extraction, volume reduction, methylation and gas chromatography. NEFA are extracted with chloroform--heptane--methanol from 50--100 microliter of serum or plasma buffered with phosphate. After adding ethyl acetate the volume of the extract is reduced under partial reflux to 5--7 microliter. Potassium carbonate, methyl iodide and a crown ether are added to the dry concentrate and the NEFA are selectively methylated with a yield of 100% by heating in a microrefluxer for 10 min. Gas chromatography is carried out with 1 microliter of the reaction mixture on a packed column by temperature-programmed operation. Thirteen individual fatty acids are determined in sera of normal adults. The coefficients of variation for 24 determinations of a pooled serum were 2.7% for the total NEFA content and 3--10% for most of the individual NEFA.