The TiHoCL panel for canine lymphoma: a feasibility study integrating functional genomics and network biology approaches for comparative oncology targeted NGS panel design

Targeted next-generation sequencing (NGS) enables the identification of genomic variants in cancer patients with high sensitivity at relatively low costs, and has thus opened the era to personalized human oncology. Veterinary medicine tends to adopt new technologies at a slower pace compared to human medicine due to lower funding, nonetheless it embraces technological advancements over time. Hence, it is reasonable to assume that targeted NGS will be incorporated into routine veterinary practice in the foreseeable future. Many animal diseases have well-researched human counterparts and hence, insights gained from the latter might, in principle, be harnessed to elucidate the former. Here, we present the TiHoCL targeted NGS panel as a proof of concept, exemplifying how functional genomics and network approaches can be effectively used to leverage the wealth of information available for human diseases in the development of targeted sequencing panels for veterinary medicine. Specifically, the TiHoCL targeted NGS panel is a molecular tool for characterizing and stratifying canine lymphoma (CL) patients designed based on human non-Hodgkin lymphoma (NHL) research outputs. While various single nucleotide polymorphisms (SNPs) have been associated with high risk of developing NHL, poor prognosis and resistance to treatment in NHL patients, little is known about the genetics of CL. Thus, the ~100 SNPs featured in the TiHoCL targeted NGS panel were selected using functional genomics and network approaches following a literature and database search that shielded ~500 SNPs associated with, in nearly all cases, human hematologic malignancies. The TiHoCL targeted NGS panel underwent technical validation and preliminary functional assessment by sequencing DNA samples isolated from blood of 29 lymphoma dogs using an Ion Torrent™ PGM System achieving good sequencing run metrics. Our design framework holds new possibilities for the design of similar molecular tools applied to other diseases for which limited knowledge is available and will improve drug target discovery and patient care.

Generation of the human iPSC lines AKOSi011-A carrying the mutation p.Pro65Ser/p.Asp35T and AKOSi012-A, carrying the mutation p.Tyr231His, derived from FAHN patient fibroblasts

Fatty acid hydroxylase-associated neurodegeneration (FAHN) is a hereditary neurodegenerative disease caused by mutations in the FA2H gene. Patients show a wide range of neurological symptoms and an abnormal myelination. Here we describe the generation of the human induced pluripotent stem cell (hiPSC) lines AKOSi011-A and AKOSi012-A, derived from FAHN-patient fibroblasts, carrying the compound heterozygous mutation p.Pro65Ser/p.Asp35Tyr and the homozygous mutation p.Tyr231His, respectively. The hiPSC lines were generated using a non-integrating Sendai virus. The obtained hiPSCs show an unobtrusive karyotype, carry the mutations of the original fibroblasts, express pluripotency markers and can differentiate into cells of the three germ layers.

Generation of the human iPSC line AKOSi010-A from fibroblasts of a female FAHN patient, carrying the compound heterozygous mutation p.Gly45Arg/p.His319Arg

Fatty acid hydroxylase-associated neurodegeneration (FAHN) is a rare childhood onset neurodegenerative disease caused by mutations in the FA2H gene. Patients display abnormal myelination, cerebellar atrophy and some have iron deposition in the central nervous system. Here we describe the generation of AKOSi010-A, a human induced pluripotent stem cell (hiPSC) line derived from fibroblasts of a female patient carrying the compound heterozygous p.Gly45Arg/p.His319Arg, using non-integrating Sendai virus. The generated iPSCs express pluripotency markers, can differentiate into cell types of the three germ layers and show a normal karyotype. This cell line displays a unique source to study the pathophysiology of FAHN.

Effective tumor cell abrogation via Venetoclax-mediated BCL-2 inhibition in KMT2A-rearranged acute B-lymphoblastic leukemia

Dysregulation of the intrinsic BCL-2 pathway-mediated apoptosis cascade is a common feature of hematological malignancies including acute B-lymphoblastic leukemia (B-ALL). The KMT2A-rearranged high-risk cytogenetic subtype is characterized by high expression of antiapoptotic protein BCL-2, likely due to the direct activating binding of KMT2A fusion proteins to the BCL2 gene. The BCL-2 inhibitor venetoclax (VEN) has proven great clinical value in other blood cancers, however, data on B-ALL is sparse and past studies have not so far described the effects of VEN on gene and protein expression profiles. Using cell lines and patient-derived in vivo xenograft models, we show BCL-2 pathway-mediated apoptosis induction and decelerated tumor cell counts in KMT2A-rearranged B-ALL but not in other cytogenetic subtypes. VEN treatment of cell line- and patient-derived xenografts reduced blast frequencies in blood, bone marrow, and spleen, and tumor cell doubling times were increased. Growth rates are further correlated with VEN concentrations in blood. In vitro incubation with VEN resulted in BCL-2 dephosphorylation and targeted panel RNA sequencing revealed reduced gene expression of antiapoptotic pathway members BCL2, MCL1, and BCL2L1 (BCL-XL). Reinforced translocation of BAX proteins towards mitochondria induced caspase activation and cell death commitment. Prolonged VEN application led to upregulation of antiapoptotic proteins BCL-2, MCL-1, and BCL-XL. Interestingly, the extrinsic apoptosis pathway was strongly modulated in SEM cells in response to VEN. Gene expression of members of the tumor necrosis factor signaling cascade was increased, resulting in canonical NF-kB signaling. This possibly suggests a previously undescribed mechanism of BCL-2-independent and NF-kB-mediated upregulation of MCL-1 and BCL-XL. In summary, we herein prove that VEN is a potent option to suppress tumor cells in KMT2A-rearranged B-ALL in vitro and in vivo. Possible evasion mechanisms, however, must be considered in subsequent studies.

Generation and Characterization of a CRISPR/Cas9-Mediated SNAP29 Knockout in Human Fibroblasts

Loss-of-function mutations in the synaptosomal-associated protein 29 (SNAP29) lead to the rare autosomal recessive neurocutaneous cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma (CEDNIK) syndrome. SNAP29 is a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein. So far, it has been shown to be involved in membrane fusion, epidermal differentiation, formation of primary cilia, and autophagy. Recently, we reported the successful generation of two mouse models for the human CEDNIK syndrome. The aim of this investigation was the generation of a CRISPR/Cas9-mediated SNAP29 knockout (KO) in an immortalized human cell line to further investigate the role of SNAP29 in cellular homeostasis and signaling in humans independently of animal models. Comparison of different methods of delivery for CRISPR/Cas9 plasmids into the cell revealed that lentiviral transduction is more efficient than transfection methods. Here, we reported to the best of our knowledge the first successful generation of a CRISPR/Cas9-mediated SNAP29 KO in immortalized human MRC5Vi fibroblasts (c.169_196delinsTTCGT) via lentiviral transduction.

[Medical notification of occupational skin diseases by dermatologists]

In accordance with § 202 SGB VII, physicians in Germany have a legal obligation to report to the statutory accident insurance institution any justified suspicion of an occupational disease. With regard to skin diseases, various occupational disease numbers (Berufskrankheitennummer = BK No.) can be considered, depending on the type of disease and the type of exposure, e.g. BK No. 3101, 3102, 3104, BK No. 5102 and others in addition to the most common BK No. 5101 and BK No. 5103. The prerequisite for a well-founded suspicion is that occupational effects exist or existed which can be brought into a causal relationship with the skin disease. Form F6000 "Medical notification of a suspected occupational disease" is used for reporting. In the case of the numerically most significant BK No. 5101, there is the special feature that even if the skin disease is classified as occupationally caused, but not as severe or repeatedly relapsing, according to § 41 (1) of the contract between physicians and the accident insurance institutions, every physician is obliged to immediately present the insured person to a dermatologist so that the so-called dermatologist procedure can be initiated to enable the rapid initiation of prevention. Since 1 January 2021, it has been stipulated that the dermatologist's report must be submitted in every case-i.e. both when there is merely the possibility and when there is a well-founded suspicion of the existence of a BK No. 5101. This ensures that preventive measures can be quickly and effectively implemented.

Ultradeep targeted sequencing reveals low allele frequencies of somatic JAK2 and MPL variants in patients with abdominal vein thromboses: results of an ongoing prospective prevalence study in Mecklenburg-West Pomerania

Myeloproliferative neoplasms are characterized by mutations in JAK2, MPL and CALR genes. Commonly in diagnostics and previous studies mainly sequencing and common PCR techniques under conventional detection limits are used.

Splanchnic vein thromboses are rare, but often appear associated with myeloproliferative neoplasms and represent serious complications.

Herein, blood from patients with abdominal vein thromboses in Mecklenburg-West Pomerania (federal district of northern Germany), included in an ongoing prospective prevalence study, was analyzed by next generation sequencing representing the complete protein coding regions of JAK2, MPL and CALR genes with a coverage of > 2000 reads, therefore an ultradeep targeting approach.

JAK2 V617F mutations were detected in 11/44 patients. In four of these cases allele frequencies ranged below the conventional cut off of 2%. MPL W515R was detected in 3/44 cases in low frequencies.

Very low allele frequencies of JAK2 and MPL variants in patients with abdominal vein thromboses may indicate early manifestations of myeloproliferative neoplasms.

Generation of two induced pluripotent stem cell lines from a female adult homozygous for the Wilson disease associated ATP7B variant p.H1069Q (AKOSi008-A) and a healthy control (AKOSi009-A)

Wilson disease (WD) is a rare, monogenic disorder caused by mutations in the gene ATP7B. A loss of function of the expressed protein leads to excessive hepatic and cerebral copper storage. In this study, we present the generation of two induced pluripotent stem cell (iPSC) lines derived from fibroblasts of a clinically asymptomatic, chelator treated female WD patient carrying the common missense mutation p.H1069Q and an age-matched female healthy control subject. The generated iPSC lines expressed pluripotency markers, showed differentiation potential and retained their parental genotype. Therefore, these cells provide a valuable resource to understand the pathophysiology of WD and can be used as model systems for drug testing.

Genetic Mutations in a Patient with Chronic Myeloid Leukemia Showing Blast Crisis 10 Years After Presentation

Since the introduction of tyrosine kinase inhibitors (TKI), the prospects for patients with chronic myeloid leukemia (CML) have improved significantly. Herein we present the case of a patient with CML who experienced blast crisis and development of acute myeloid leukemia (AML) 10 years after presentation. The CML was characterized by the gene fusion of breakpoint cluster region BCR and tyrosine-protein kinase ABL1. During treatment different therapeutic protocols including imatinib, nilotinib, dasatinib and ponatinib were applied due to development of resistance or non-response. Fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS) were used to describe cytogenetic and molecular aberrations elucidating the development into AML: A loss of chromosome 7, as well as an arising frequency of variants in the gene met proto-oncogene MET (p.T110I) and tyrosine-protein phosphatase non-receptor type 11 PTPN11 (p.Q510L) was observed. This report describes the comprehensive characterization of a clinical case showing multiple therapeutic resistances correlated with genetic aberrations.

Decitabine demonstrates antileukemic activity in B cell precursor acute lymphoblastic leukemia with MLL rearrangements

Background

Promotor hypermethylation of CpG islands is common in B cell precursor acute lymphoblastic leukemia (BCP-ALL) with mixed lineage leukemia (MLL) gene rearrangements. Hypomethylating agents (HMA) such as azacitidine (AZA) and decitabine (DEC) reduce DNA hypermethylation by incorporation into DNA and were successfully introduced into the clinic for the treatment of myeloid neoplasias.

Methods

Here, we investigated whether HMA induce comparable biological effects in MLL-positive BCP-ALL. Further, efficacy of HMA and concomitant application of cytostatic drugs (cytarabine and doxorubicin) were evaluated on established SEM and RS4;11 cell lines. In addition, promising approaches were studied on BCP-ALL cell line- and patient-derived xenograft models.

Results

In general, DEC effects were stronger compared to AZA on MLL-positive BCP-ALL cells. DEC significantly reduced proliferation by induction of cell cycle arrest in G0/G1 phase and apoptosis. Most sensitive to HMA were SEM cells which are characterized by a fast cell doubling time. The combination of low-dose HMA and conventional cytostatic agents revealed a heterogeneous response pattern. The strongest antiproliferative effects were observed when ALL cells were simultaneously exposed to HMA and cytostatic drugs. Most potent synergistic effects of HMA were induced with cytarabine. Finally, the therapeutic potential of DEC was evaluated on BCP-ALL xenograft models. DEC significantly delayed leukemic proliferation in xenograft models as demonstrated longitudinally by non-invasive bioluminescence as well as ¹⁸F-FDG-PET/CT imaging. Unexpectedly, in vivo concomitant application of DEC and cytarabine did not enhance the antiproliferative effect compared to DEC monotherapy.

Conclusions

Our data reveal that DEC is active in MLL-positive BCP-ALL and warrant clinical evaluation.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0607-3) contains supplementary material, which is available to authorized users.

Genomic heterogeneity in primary colorectal carcinomas and their metastases: born bad or brought up a villain?

Progression of solid cancers, colorectal carcinomas among them, from their primaries to metastatic lesions traditionally is thought to proceed by a stepwise acquisition of and selection for genomic aberrations. To test if patterns of genomic aberrations would be consistent with this model, we studied 10 colorectal carcinoma primary-metastasis pairs, 9 with 1 liver metastasis each and 1 with 2 metastases. Next-generation targeted sequencing (50-gene panel) with samples obtained from different regions of the primaries and their metastases demonstrated 1-11 gene mutations per lesion. But only in 2 tumors were there seen mutations in all samples from the metastasis and not any of the primaries (BRAF^D594N and SMARCB1^R377C mutation, respectively). However, allelotyping the multiregional samples with polymorphous microsatellite markers (17p13.1, D9S942, D9S1748, D5S346, D5S1385) and DNA methylation studies with a marker panel (MLH1, CDNK2A, NEUROG1, CRABP1, CACNA1G, IGF2, RUNX3, SOCS1) showed remarkably "insular" genomic aberrations in all cases for at least some of the analyses. The marked preponderance of mutations shared by the primaries and their metastases throughout the lesions over mutations private to metastases suggests that, at least in many cases, colorectal carcinomas might be endowed with a mutational load sufficient for fully fledged metastases even at a very early stage ("born bad"). But the very focal allelic imbalances and methylations observed here, hypothetically, could play a role in clinically metastasizing disease, a process of years rather than months and very much a matter of tumor-host interactions when tumor cells adapt to the host microenvironment.

[Effects of intravenous clonidine on recovery and postanaesthetic analgesic requirements.]

Pain and pain-related sympathoadrenergic reactions (hypertension, tachycardia) accompanied by nausea, vomiting and shivering are the most common side effects of recovery from anaesthesia. The alpha(2)agonist clonidine acts as a sedative, anxiolytic, antihypertensive, antiemetic, antisialogogue and decreases the incidence of shivering. Thus, we studied the effects of intraoperatively administered clonidine on the recovery period and the postoperative analgesic requirements in patients undergoing maxillofacial surgery.

METHODS

After approval by the local Ethics Commitee and after informed consent had been given, 40 patients scheduled for elective maxillofacial surgery were included in this double-blind, randomized study. As a supplement to standardized general anaesthesia (isoflurane, N(2)O), the patients received either clonidine 5 mug/kg or placebo during the last hour of the operation. Blood pressure, heart rate, time of recovery, and sedation and pain scores were measured postoperatively. The occurrence of nausea, vomiting or shivering was noted, as were the requirements of piritramide for analgesia, which was administered on demand in titrating dosages, and of nifedipine for systolic blood pressure exceeding 180 mm Hg.

RESULTS

The two groups were comparable regarding biometric parameters, ASA-classification and duration of anaesthesia. Clonidinetreated patients were later in opening their eyes (22.5+/-11.9 min vs 17.9+/-10.9; n.s.) and the ability to state their dates of birth returned later (32.2+/-11.6 min vs. 25.7+/-12.8;P<0.05). Pain was more frequent in the placebo group (P<0.05 after 30 min), and there-fore, these patients required much more piritramid (P<0.01). The sedation scores showed no significant differences. No vomiting occurred in the clonidine group, and shivering was less frequent (P<0.01). The placebo group received more nifedipine (P<0.05) because the rate-pressure product was higher (P<0.01).

DISCUSSION

Opiates are frequently used as analgesics after maxillofacial surgery, even though their most common side effect-respiratory depression, nausea and vomiting-are particularly dangerous in these patients because of the obstruction of the upper respiratory tract. Self-titration of the opiate dosage on demand can decrease the incidence of serious side effects. Clonidine administered intraoperatively caused a profound reduction in analgesic requirements in this study. Additional opiate administration in the postoperative period was unnecessary in nearly all clonidine-treated patients. The attenuating effect on sympathoadrenergic reactions leads to lowering of the rate-pressure product and may be of advantage for patients suffering from arterial hypertension, angina pectoris or bronchial asthma. The slower emergence from anaesthesia following clonidine administration is probably caused by double-blind study properties preventing full consideration of the decreased isoflurane requirements after clonidine.

A predicted operon map for Mycobacterium tuberculosis

The prediction of operons in Mycobacterium tuberculosis (MTB) is a first step toward understanding the regulatory network of this pathogen. Here we apply a statistical model using logistic regression to predict operons in MTB. As predictors, our model incorporates intergenic distance and the correlation of gene expression calculated for adjacent gene pairs from over 474 microarray experiments with MTB RNA. We validate our findings with known examples from the literature and experimentation. From this model, we rank each potential operon pair by the strength of evidence for cotranscription, choose a classification threshold with a true positive rate of over 90% at a false positive rate of 9.1%, and use it to construct an operon map for the MTB genome.

Improved test of time dilation in special relativity

An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2).

Rate coefficients and final states for the dissociative recombination of LiH+

The dissociative recombination of LiH+ ions with low-energy electrons is observed at a storage ring and the final states are analyzed using fragment imaging and field ionization techniques. The rate coefficient is found to be larger than its estimated value used in astrophysical models. Mostly the highest energetically possible Rydberg states of the lithium atom are populated by the reaction, indicating a common trend for molecular recombination via the noncrossing mode.

Two- and three-body kinematical correlation in the dissociative recombination of H(3)(+)

Fragmentation patterns for dissociative recombination of the triatomic hydrogen molecular ion H(3)(+) in the vibrational ground state have been measured using the storage ring technique and molecular fragment imaging. A broad distribution of vibrational states in the H(2) fragment after two-body dissociation and a large predominance of nearly linear momentum geometries after three-body dissociation are found. The fragmentation results are directly contrasted with Coulomb explosion imaging data on the initial H(3)(+) geometry, compared to existing wave-packet calculations, and considered in the light of a simple physical picture.

Influence of magnetic fields on electron-Ion recombination at very low energies

Radiative recombination (inverse photoionization) is believed to be well understood since the beginning of quantum mechanics. Still, modern experiments consistently reveal excess recombination rates at very low electron-ion center-of-mass energies. In a detailed study on recombination of F6+ and C6+ ions with magnetically guided electrons we explored the yet unexplained rate enhancement, its dependence on the magnetic field B, the electron density n(e), and the beam temperatures T( perpendicular) and T( ||). The excess scales as T(-1/2)( perpendicular) and, surprisingly, as T(-1/2)( ||), increases strongly with B, and is insensitive to n(e). This puts strong constraints on explanations of the enhancement.

[Degradation of halothane, enflurane, and isoflurane by dry soda lime to give carbon monoxide]

In the presence of completely dry soda lime volatile anaesthetics will decompose to carbon monoxide (CO). In an in vitro study, the absorbent (soda lime, ICI) was dried with a constant gas flow of 11/min oxygen for 120 h. The weight loss during the drying was 17.1%. Two vol% of halothane, enflurane or isoflurane in oxygen was administered with a constant flow of 0.51/min oxygen through the completely dry absorbent. Concentrations of gases were measured before and after the absorbent using mass spectrometry (MGA 1100, Perkin-Elmer) and an electrochemical NO monitor (Mini PAC CO, Dräger). The temperature inside the soda lime was monitored continuously. Shortly after adding the anaesthetic to the oxygen passing through the absorbent, carbon monoxide appeared in the outlet of the soda lime container. The measured peak concentrations varied around 450 ppm (halothane), 3500 ppm (enflurane) and 3800 ppm (isoflurane). The temperature inside the absorbent rose from the ambient temperature (19.8 degrees C) to a maximum of 52.1 degrees C during CO production and decreased when the CO production lowered after approximately 1 h (all anaesthetics). During CO production no measurable concentration of halothane left the absorber. After passing through the absorbent the concentrations of isoflurane and enflurane were slightly lower than the corresponding concentrations in the fresh gas measured before absorption.

Evaluation of two electrochemical monitors for measurement of inhaled nitric oxide

Inhaled in low concentrations, nitric oxide (NO) acts as a potent pulmonary vasodilator, but when inhaled in high concentrations NO and its metabolite NO2 are potentially toxic molecules. Thus, an accurate and reproducible measurement of both NO and NO2 is necessary, and changes in NO concentration need to be detected instantly to avoid lung damage (high concentrations) or failure of NO therapy (low concentrations; unnoticed interruption of NO supply). We investigated two electrochemical NO monitors (Sensor Stik 4586 and Dräger PAC II) for accuracy and time constants. Both provided accurate and reproducible results at different NO concentrations. Known NO concentrations (standards: 10, 50, 75 ppm) were detected within a 3% tolerance, and acceptable time constants were seen when NO concentration was abruptly increased from zero to 50 ppm. The display read the final value within 60 s with the Sensor Stik and 11 s with the Dräger PAC II. Significant differences were seen when the NO concentration was rapidly reduced from 50 ppm to zero. The Sensor Stik took more than 2 h to reach zero, whereas the PAC II took 60 s.

[Patient-controlled analgesia with clonidine and piritramide]

Following parenteral administration, clonidine has analgesic effects at both cerebral and spinal levels. Patient-controlled analgesia (PCA) makes it possible to determine equipotent dosages of analgesics by relating analgesic consumption per time to the levels of analgesia obtained in comparable patient populations. Therefore, we studied the equipotency ratios of clonidine and piritramide and the incidence of undesired side effects in the treatment of postoperative pain in patients undergoing maxillo-facial surgery.

METHODS

After approval of the local ethics committee and informed consent 40 patients (age > 18 year, ASA I-III) were studied. Following randomization, the patients each received a PCA device containing either clonidine (bolus 30 micrograms), or piritramide (bolus 1.5 mg) for treatment of postoperative pain (lockout interval 5 min in both groups). During the postoperative period, pain was determined using a visual analogue scale, while analgesic consumption, sedation, haemodynamic parameters, respiration rate, and the occurrence of undesired side effects were documented additionally.

RESULTS

The groups had comparable distributions of biometric data, duration of anaesthesia, and ASA classification. Pain level decreased significantly (P < 0.0001) in both groups during the first 2 h of PCA. Mean arterial pressure and heart rate were lower (P < 0.05) in the clonidine group 4 and 6 h after PCA onset, while the degree of sedation after 2 (P < 0.01) and 6 (P < 0.05) h was higher than in the piritramide group. Nausea and vomiting were more frequent (P < 0.05) in the piritramide group. Both groups showed a wide interpatient variation in analgesic requirement. The equipotency ratio clonidine/piritramid was 1:63.7.

CONCLUSION

Intravenous clonidine is a potent analgesic and is suitable or the treatment of postoperative pain following maxillo-facial surgery. The analgesic potency of 150 micrograms clonidine i.v. was equivalent to that of 9.56 mg piritramide i.v. Nausea and vomiting occurred more rarely in the clonidine group, while deeper sedation was observed more frequently than in the piritramide group. Owing to the wide interindividual variation of analgesic consumption, clonidine dosages have to be adjusted to the actual requirements.

[Intraoperative thrombosis of the inferior vena cava]

A pre-term infant weighing 900 g, gestational age 25 weeks, developed an acute abdomen. Intravenous lines had been inserted previously in the left (silastic catheter) and right (24 G cannula) saphenous veins in the neonatal intensive care unit. During surgical exploration, a perforation of the terminal ileum was found. The operation consisted in partial resection of the perforated ileum with an end-to-end anastomosis and a double-lumen colostomy. Major blood loss during the procedure caused serious haemodynamic problems. Despite transfusion of erythrocyte (100 ml), thrombocytes (75 ml), and albumin (50 ml), the patient developed bradycardia and hypotension. Administration of atropine, adrenaline, and calcium i.v. had no effect. The operation could be finished only with extrathoracic resuscitation. When the drapes were removed, livid, swollen lower limbs raised the suspicion of an acute thrombosis of the inferior vena cava. After insertion of a 24 G i.v. cannula into a vein of the right upper arm, the circulation stabilised after rapid transfusion of 40 ml blood and 25 ml thrombocytes and resuscitation was successful. Paediatricians and anaesthesiologists must consider the risk of thrombosis of the vena cava. If venous lines in the lower limbs are not visible to the anaesthesiologist during the operation, venipuncture of veins of an upper limb is recommended before starting the surgical procedure. Due to the high incidence of vena cava thrombosis caused by central venous lines and the difficulty of peripheral venipuncture in pre-termintanty, a safe venous line should be inserted if necessary by pre-operative venesection.

[Nitric oxide in therapy of pulmonary hypertension after correction of congenital single atrium]

We report on a 19-month-old boy with congenital single atrium. Cardiac catheterization preceding the surgical repair revealed an elevated pulmonary artery pressure of 60/15 mmHg (mean pressure 40 mmHg). Pulmonary flow was 8.4 l/min.m2 and systemic flow was 5.5 l/min.m2. Pulmonary arteriolar resistance was elevated to 4.2 U.m2 with 64% left-right shunt and 25% right-left shunt. Arterial O2-saturation varied around 90%. After surgical repair (insertion of a Goretex patch), the patient required mechanical ventilation with 100% oxygen for adequate oxygenation. Cardiac catheterization was repeated on the first postoperative day. No residual shunts were found. The pulmonary artery pressure was 66/40 mmHg (mean pressure 50 mmHg), systemic arterial pressure was 85/62 mmHg (mean pressure 68 mmHg). Cardiac index was 2.8 l/min.m2, pulmonary vascular resistance was 12 U.m2. After administration of prostacyclin a significant decrease of pulmonary artery pressure was observed, but without changing the ratio between pulmonary and systemic pressure. The AaDO2 varied between 400 and 580 mmHg and the oxygenation-index (PaO2/FiO2) was less than 1.0. In this situation, an attempt with inhaled nitric oxide (NO) was performed. After adding 20 ppm NO to the inspired gas, the AaDO2 decreased significantly from 580 to 270 mmHg and the oxygenation-index (OI) rose from 0.9 to 1.5. The inspired fraction of oxygen could be reduced quickly to 60%. During the next days, the concentration of NO was reduced stepwise to 1 ppm. Finally, the AaDO2 was within the normal range (25-65 mmHg) and the OI rose to a level about 4.0. The FiO2 could be reduced to 30% and nitric oxide therapy could be stopped and the child could be extubated.

[Malignant hyperthermia in swine during isoflurane anesthesia]

A case of porcine malignant hyperthermia (MH) is reported, which occurred during a cardiological animal experiment under general anaesthesia using isoflurane as inhalational anaesthetic. Initially, tachycardia (238 bpm) and a sudden increase of end-exspiratory pCO2 were noticed. Discontinuation of isoflurane followed by administration of dantrolene (7 mg/kg body weight) led to a rapid recovery. Two days later, no difference in clinical state was apparent in comparison with the remaining swine. After regular euthanasia, acute muscle necrosis was seen macroscopically in back and glutaeal muscles, which was confirmed by histological examination. The rise of end-tidal pCO2 was the striking symptom thus allowing the detection of the incipient malignant hyperthermia. Early onset of dantrolene therapy is shown to be sufficient in termination of this hyperacute complication, and may prevent its deleterious outcome. Therefore, the administration of dantrolene should be taken into account in case of porcine MH, especially in time-consuming and costly series of animal experiments.

[Postoperative monitoring of microvascular flap repair with pulse oximetry--initial experience]

The surgical success of microvascular free flaps or pedicled flaps depends on the function of the nutritive vessels. Complications such as thrombosis or vessel kinking, are dangerous and may result in flap loss. During the last decade, different methods were tested for their capability of monitoring flap perfusion. We report our preliminary experience with the continuous and non-invasive pulse oximetry by using a special reflection sensor positioned on the surface of the flap.

Chemistry of fruit flies: Glandular secretion ofBactrocera (Polistomimetes) visenda (Hardy)

The major component (>90% of volatiles) of the male rectal glandular extract of the nonpest speciesBactrocera visenda (Hardy) is 3-methyl2-butenyl acetate, with minor components being the isomeric 3-methyl-3-butenyl acetate, the homologous esters, 3-methyl-2-butenyl propanoate and 3-methyl-2-butenyl formate, along with 3-methyl-2-buten-1-ol, 3-methyl-2-butenal, and 3-methylbutyl acetate. None of these compounds has been identified previously from aBactrocera species, supporting the view thatBactrocera visenda is taxonomically distant from otherBactrocera species identified from the Australian mainland. This collection of compounds adds to the known types utilized by dipteran species and emphasizes their extensive biosynthetic capability.

[Suitability of capacitive sensors for measuring relative humidity in anesthetic gas systems]

A capacitive sensor was tested for its suitability for measuring relative humidity in an anaesthetic gas circuit. The valvo sensor PH1 was tested using various different anaesthetic gas mixtures. Measuring accuracy was influenced neither by such volatile anaesthetics as isoflurane and halothane, nor by oxygen or nitrous oxide. The response time of the sensor depends on its position within the gas, and in the most favourable case is about 3 minutes. The sensor is readily incorporated within an existing gas circuit. The linearity of the characteristic curve must be corrected by external electronic compensation to avoid measuring problems in the lower humidity range.

Metabolism of Dibenzofuran by Pseudomonas sp. Strain HH69 and the Mixed Culture HH27

A Pseudomonas sp. strain, HH69, and a mixed culture, designated HH27, were isolated by selective enrichment from soil samples. The pure strain and the mixed culture grew aerobically on dibenzofuran as the sole source of carbon and energy. Degradation proceeded via salicylic acid which was branched into the gentisic acid and the catechol pathway. Both salicylic acid and gentisic acid accumulated in the culture medium of strain HH69. The acids were slowly metabolized after growth ceased. The enzymes responsible for their metabolism showed relatively low activities. Besides the above-mentioned acids, 2-hydroxyacetophenone, benzopyran-4-one (chromone), several 2-substituted chroman-4-ones, and traces of the four isomeric monohydroxydiben-zofurans were identified in the culture medium. 2,2′,3-Trihydroxybiphenyl was isolated from the medium of a dibenzofuran-converting mutant derived from parent strain HH69, which can no longer grow on dibenzofuran. This gives evidence for a novel type of dioxygenases responsible for the attack on the biarylether structure of the dibenzofuran molecule. A meta -fission mechanism for cleavage of the dihydroxylated aromatic nucleus of 2,2′,3-trihydroxybiphenyl is suggested as the next enzymatic step in the degradative pathway.

Volatile Secretions in Three Species of Dufourea (Hymenoptera: Halictidae) Bees: Chemical Composition and Phylogeny

Volatile secretions from Dufour’s glands in three species of Dufourea bees, Dufourea (Halictoides) dentriventris (Nylander). D.(H.) inermis (Nylander) and D. (Dufourea) minuta Lepelletier have been studied by gas chromatography and mass spectrometry. It was found that the secretions are composed of complex blends of straight chain saturated and unsaturated 2- and 3-ketones and scries of hexanoic and octanoic esters. Cephalic secretions from males and females of D.(H.) inermis and D.(D.) minuta contain sex- and species-specific blends of methylcarbinols and corresponding long chain carboxylic esters. Mass spectrometric fragmentation patterns of esters are described.