Narcotrend-assisted propofol/remifentanil anaesthesia vs clinical practice: does it make a difference?

BACKGROUND: The Narcotrend is a computer-based EEG monitor designed to measure the depth of anaesthesia. The aim of the present study is to test the hypothesis that the intraoperative level of anaesthetic depth differs if decision-making is guided by Narcotrend monitoring or not. METHODS: Forty-eight patients undergoing elective surgery were randomized to receive a Narcotrend-controlled propofol/remifentanil anaesthetic regimen or standard clinical practice. In the EEG group, anaesthesia was adjusted to achieve a Narcotrend level of D2-E0, which is recommended for moderate to deep anaesthetic depth for surgery. EEG values were recorded continuously every 20 s in both groups. Depending on data distribution, group comparisons of the EEG parameters, propofol plasma concentration, and recovery characteristics were performed by analysis of variance for repeated measurements or non-parametric statistics. RESULTS: About 62 (sd 29)% of the Narcotrend values were within the target level in the EEG group during maintenance of anaesthesia; this was true for 64 (26)% of the data in the non-EEG group. The variance of the Narcotrend data was significantly lower in the EEG group compared with the non-EEG group [median: 0.4 (range: 3.5) vs 0.6 (2.5); P = 0.048]. There was no difference in propofol or remifentanil dosage, propofol plasma concentrations, and time for extubation. Ten minutes after extubation, visual analogue scores for nausea indicated a lower incidence in the Narcotrend group [7 (15) vs 24 (34); P = 0.005]. CONCLUSIONS: Guidance of anaesthesia with the Narcotrend-monitor leads to fewer deviations from a defined target than clinical assessment of anaesthetic depth only. This results in lower scores of nausea in the immediate period after anaesthesia.

Spectral karyotyping of human, mouse, rat and ape chromosomes--applications for genetic diagnostics and research.

Spectral karyotyping (SKY) is a widely used methodology to identify genetic aberrations. Multicolor fluorescence in situ hybridization using chromosome painting probes in individual colors for all metaphase chromosomes at once is combined with a unique spectral measurement and analysis system to automatically classify normal and aberrant chromosomes. Based on countless studies and investigations in many laboratories worldwide, numerous new chromosome translocations and other aberrations have been identified in clinical and tumor cytogenetics. Thus, gene identification studies have been facilitated resulting in the dissection of tumor development and progression. For example, different translocation partners of the TEL/ETV6 transcription factor that is specially required for hematopoiesis within the bone marrow were identified. Also, the correct classification of complex karyotypes of solid tumors supports the prognostication of cancer patients. Important accomplishments for patients with genetic diseases, leukemias and lymphomas, mesenchymal tumors and solid cancers are summarized and exemplified. Furthermore, studies of disease mechanisms such as centromeric DNA breakage, DNA double strand break repair, telomere shortening and radiation-induced neoplastic transformation have been accompanied by SKY analyses. Besides the hybridization of human chromosomes, mouse karyotyping has also contributed to the comprehensive characterization of mouse models of human disease and for gene therapy studies.

Effects of higher-order nuclear structure and Rad51 overexpression on radiation-induced chromosome rearrangements.

The microchromosomes (MICs) in chicken DT40 lymphocytes are usually clustered in the center of the nucleus, whereas the macrochromosomes (MACs) are preferentially located toward the nuclear periphery. This compartmentalized architecture of the nucleus is associated with a low frequency of translocations between MICs and MACs after induction of DNA breaks by a radiation track(s). In contrast, the MICs in chick embryo fibroblasts (CEFs) tend to be located throughout the entire nuclear volume. The resulting side-to-side arrangement of MIC and MAC territories favors radiation-induced MIC/MAC translocations, which occur more frequently in CEF cells than MIC/MIC or MAC/MAC rearrangements. Collectively, our results suggest that preformed physical contacts are a prerequisite for the generation of chromosome rearrangements through recombinational repair of DNA damage. Cell type-specific higher-order nuclear organization may prevent or stimulate the formation of particular chromosome aberrations in pathology and evolution. Ectopic expression of the recombination protein Rad51 can protect cells from radiation-induced translocations. The repair activity of overexpressed Rad51 is more important for cells that are irradiated in S/G(2) phase than for cells in G(1) phase. Evidently, homologous recombination between sister chromatids of a replicated chromosome is more frequent than that between homologous or heterologous chromosomes during G(1) phase.

Towards identification of individual homologous chromosomes: comparative genomic hybridization and spectral karyotyping discriminate between paternal and maternal euchromatin in Mus musculus x M. spretus interspecific hybrids.

We have developed an in situ technique to label individual euchromatic chromosome arms in interspecific crosses between Mus musculus (MMU) and M. spretus (MSP). The MMU and MSP genomes diverged 2-3 million years ago and show an overall sequence divergence of approximately 1%. Comparative hybridization of MMU versus MSP DNA and subsequent spectral analysis of the euchromatic hybridization profiles discriminated between maternal (MMU) and paternal (MSP) chromosomes in F(1) hybrids. Dispersed repetitive DNA elements were the preferred hybridization target of MMU DNA on maternal chromosomes and of MSP DNA on paternal chromosomes. Differences in centromeric satellite DNAs were detected by conventional fluorescence in situ hybridization and served as internal controls. Our experiments suggest that it is possible, in principle, to discriminate between paternal and maternal chromosomes on the basis of sequence differences.

Evaluation of rapid microsatellite analysis of paraffin-embedded specimens in screening for hereditary nonpolyposis colorectal cancer.

Length alterations in short repetitive DNA sequences, termed microsatellite instability (MSI), are used as a diagnostic criterion of replication errors caused by various mutations in at least five mismatch repair genes. Therefore, MSI analysis is useful in clinical practice to identify patients with hereditary nonpolyposis colorectal cancer (HNPCC). MSI can be detected by amplification of microsatellite loci in DNA extracted from paraffin-embedded tumor and corresponding peritumoral specimens after numerous time consuming steps limiting the clinical utilities. Rapid microsatellite analysis, a efficient and rapid DNA extraction technique based on Triton X-100 preincubation, was compared with the conventional DNA extraction for HNPCC screening in colorectal tumor specimens from 12 patients. Five complex and two noncomplex (CA)n microsatellite loci were tested, with use of multicolor fluorescent analysis. MSI and loss of heterozygosity in colorectal tumor samples could equally be assessed with the two DNA preparation methods, whereas the number of initially unsuccessful DNA extractions from paraffin-embedded tissue specimens and overall duration for MSI analysis were significantly reduced when rapid microsatellite analysis was used. A replication error-positive phenotype was detected in 2 of 10 patients with a positive family history for colorectal cancer, and diagnosis of HNPCC was finally confirmed by detection of a specific germline mutation. The described rapid microsatellite analysis is less time consuming and more efficient, and, in general, it reduces the risk of contamination by limiting the number of steps required. Therefore, it might replace current DNA extraction procedures. Furthermore, techniques using fluorescent polymerase chain reaction and semiautomated DNA sequencer allow for precise, observer-independent, and rapid scoring in MSI and loss of heterozygosity assessment. A combination of our rapid DNA extraction method and the use of a highly specific microsatellite marker might improve replication error analysis in HNPCC screening.

Collagen fibril structure in lamprey.

X-ray diffraction and electron microscopy are used to compare the molecular and higher order structure of collagen fibrils in three tissues of the lamprey: the dermis, perinotochord and notochord sheath. These lamprey tissues are known to contain five distinct genetic types of fibrillar collagen. The modes of axial and lateral packing of collagen molecules in fibrils of the lamprey tissues demonstrate the three major motifs seen in higher vertebrate D-periodic collagen fibrils. In particular, lamprey dermis was found to have a decreased D period resulting from a molecular tilt that is seen in skins of higher vertebrates. Our results suggest the molecular-packing motifs for collagen fibrils were in place at the dawn of vertebrate evolution and have been conserved since. In contrast, the diameters of fibrils and their spatial orientation in lamprey tissues do not in general, correspond to features found in mammalian tissues. Only for lamprey notochord is there a strong similarity, with fibril diameters and organization closely resembling those seen in type II tissues of higher vertebrates. This suggests that for all tissues except those with type II collagen, higher level organization of fibrils evolved along with the diversification of vertebrates.

Glycation alters collagen fibril organization.

Incubation of rat tail tendon in 0.2M ribose results in accelerated non-enzymatic glycosylation of collagen, with the formation of fluorescent cross-links between molecules and decreased solubility. Electron micrographs of tendon cross-sections show an increased fibril packing density with increasing degrees of glycation. After a one-week incubation in ribose, every fibril appears in close contact with all of its neighbors, and the packing density has increased to 76%, from a value of 62% in controls. Irregular diameters and fusion of fibrils also are seen. All of the fibrils in a bundle appear to become cross-linked together, creating a larger stress bearing unit. This model is consistent with stress-strain curves showing a large increase in tensile stress and stiffness after a one-week incubation period in ribose. The diameters of the collagen fibrils increase in size in glycated tendon. We hypothesize larger diameters result from an increased resistance to shrinkage during the specimen preparation process, as a result of the rigid sugar derived cross-links. Closer fibril packing, increased fibril diameters, and irregular diameters have been reported in diabetic tissues, and may result from decades of glycation induced cross-link accumulation.

Fibril-forming collagens in lamprey.

Five types of collagen with triple-helical regions approximately 300 nm in length were found in lamprey tissues which show characteristic D-periodic collagen fibrils. These collagens are members of the fibril forming family of this primitive vertebrate. Lamprey collagens were characterized with respect to solubility, mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, carboxylmethyl-cellulose chromatography, peptide digestion patterns, composition, susceptibility to vertebrate collagenase, thermal stability, and segment long spacing-banding pattern. Comparison with fibril-forming collagens in higher vertebrates (types I, II, III, V, and XI) identified three lamprey collagens as types II, V, and XI. Both lamprey dermis and major body wall collagens had properties similar to type I but not the typical heterotrimer composition. Dermis molecules had only alpha 1(I)-like chains, while body wall molecules had alpha 2(I)-like chains combined with chains resembling lamprey type II. Neither collagen exhibited the interchain disulfide linkages or solubility properties of type III. The conservation of fibril organization in type II/type XI tissues in contrast to the major developments in type I and type III tissues after the divergence of lamprey and higher vertebrates is consistent with these results. The presence of type II and type I-like molecules as major collagens and types V and XI as minor collagens in the lamprey, and the differential susceptibility of these molecules to vertebrate collagenase is analogous to the findings in higher vertebrates.

Isolate of Anaplasma marginale not transmitted by ticks.

The tick-borne transmissibility of 2 isolates of Anaplasma marginale was compared. Dermacentor variabilis were exposed to A marginale as nymphs by feeding on 1 of 4 splenectomized calves during periods of ascending parasitemia (maximum 49% to 81% parasitized erythrocytes) induced by injection of a stabilate. Tick-borne transmission was attempted, using 26 to 224 adult ticks within 30 to 220 days after molting. Adult D variabilis did not transmit an Illinois isolate of A marginale in 7 tick-borne transmission experiments (P = 0.0047), including 2 experiments in which calves were inoculated IV with homogenates of adult ticks. In contrast, a Virginia isolate of A marginale was readily transmitted by the same tick colony. Thus, previously reported morphologic and immunologic differences among A marginale isolates may extend to tick-borne transmissibility. The Virginia and Illinois A marginale isolates had an inclusion appendage that was not a marker for tick transmissibility.

Type II collagen of lamprey.

The major collagen in lamprey notochord is type II, as determined by its amino acid composition and solubility properties. This collagen has a distribution of charged residues indistinguishable from higher vertebrate Type II collagens as judged by its SLS banding pattern. Lamprey type II collagen has a higher thermal stability than lamprey skin collagen, in contrast to the identical melting temperatures for these types in mammals. A minor collagen in lamprey notochord has solubility properties, amino acid composition, and electrophoretic mobility similar to that of 1 alpha, 2 alpha, 3 alpha collagen in human cartilage.

Morphogenesis in wing imaginal discs: its relationship to changes in the extracellular matrix.

An extracellular matrix (ECM) lies between the upper and lower epithelial layers of the wing imaginal discs of moths. Organization and composition of this extracellular matrix, as revealed by staining with ruthenium red, tannic acid, and alcian blue, changes in concert with levels of hormones in the haemolymph. The ECM of the wing imaginal disc is an environment for cellular movements. Reorganization of the matrix and increase in ecdysteroid level is coupled with the proximal----distal migration of tracheal cells as well as the distal----proximal outgrowth of sensory neurons.

Dose-related pharmacokinetics of coumarin, 7-hydroxycoumarin and 7-hydroxycoumarin glucuronide upon intraperitoneal administration of coumarin and 7-hydroxycoumarin in the rat.

Blood concentration-time data of coumarin (C), 7-hydroxycoumarin (7-HC) and 7-hydroxycoumarin glucuronide (7-HCG) were obtained in rats receiving intraperitoneal doses of C ranging from 2.5 to 60 mg/kg and of 7-HC ranging from 2.5 to 20 mg/kg. Coumarin blood levels were fit to pharmacokinetic models using computer programs including NONLIN, modified ESTRIP, RESID and AUCRPP. The other molecular species were treated pharmacokinetically by linear least squares regression analysis. C blood concentrations were indicated to be dose-dependent at doses greater than 10 mg/kg. Only trace amounts of 7-HC were found upon C administration, however, 7-HCG was found in measurable quantities at all dose levels. The blood concentration-time data of 7-HC and 7-HCG were very erratic with considerable intersubject variation. 7-HC levels upon 7-HC dosing were found to have extremely short half-lives of elimination for all animals tested. Deviation from linearity was apparent at the 20 mg/kg dose for 7-HC. The 7-HCG metabolite upon 7-HC dosing also showed dose-dependent kinetics at the 20 mg/kg dose. 7-HCG was found to appear at variable rates in the blood with peak times ranging from about 2 to 50 min.

Investigation of the dose-response relationship upon intraperitoneal administration of coumarin and 7-hydroxycoumarin on the carrageenan induced edema of the rat hind paw.

The dose-response relationship upon intraperitoneal administration of coumarin (C) and 7-hydroxycoumarin (7HC) in rats was evaluated using the carrageenan induced edema of the hind paw. In a preliminary study C was indicated to reduce the 4-h edema at doses of 10 to 60 mg/kg i.p. Doses of 2.5 and 5 mg/kg were not effective. In the same study 7HC did not appear to be effective over a dose range of 0.01 to 20 mg/kg. A second study based on a completely randomized design indicated 7HC to be ineffective at doses of 2.5, 5, 10 and 20 mg/kg for edema measurements made at 3, 4, 5 and 6 h after the injury stimulus. C, however, was found to be effective at doses of 5, 10 and 20 mg/kg at 3, 4 and 5 h. C dose of 2.5 mg/kg was ineffective at all times and the 20 mg/kg dose appeared to be ineffective at the 6-h measurement. Resolution of the edema after 5 h did not appear to be enhanced by either C or 7HC administration as the rate of decay appeared to be parallel for controls and the treated animals. The edema model used here would possibly be very useful for further pharmacological investigation of the benzopyrones due to its simplicity, reproducibility and speed.

Tissue distribution of coumarin, 7-hydroxycoumarin and their 7-hydroxy metabolites following parenteral administration of 14C-labeled compound in the DBA/lac mouse.

The time related tissue distributions of coumarin (C), 7-hydroxycoumarin (7HC) and their metabolites were studied in DBA/lac mice following retro-orbital injection of 14C-labeled compound. The activity was determined as dpm/ml or g wet weight over a period of 120 min. C was found in blood, kidney, liver, muscle, brain, heart, lung and fat but not in the testes. Upon C dosing, 7HC was found in kidney, liver and lung; 7-hydroxycoumarin glucuronide (7HCG) was found in blood, kidney and liver; 7-hydroxycoumarin sulfate (7HCS) was found in the blood, kidney and lung. Unidentified glucuronide and sulfate metabolites were detected in blood, kidney, liver and lung. Two unidentified unconjugated metabolites were detected in the kidney and liver. Unidentified water soluble metabolites were detected in kidney, liver, muscle, heart and testes. Upon 7HC dosing only 7HC, 7HCG and 7HCS were detected in any organ. 7HC and 7HCG were found in blood, kidney, liver, muscle and lung. 7HCS was detected in blood, kidney, liver and lung. Upon both C and 7HC dosing the kidney and liver contained the highest levels of radioactivity.

Pharmacokinetics of coumarin, 7-hydroxycoumarin and 7-hydroxycoumarin glucuronide in the blood and brain of gerbils following intraperitoneal administration of coumarin.

Blood and brain concentration-time profiles were obtained in gerbils following intraperitoneal administration of coumarin (C). The data were fit to one- or two-compartment models using several computer programs including NONLIN, modified ESTRIP, RESID and AUC-RPP. The data indicate that coumarin distributes rapidly into the brain tissue reaching about one half the blood concentration at peak time. The peak time brain coumarin concentration and subsequent rapid removal from brain correlates well with the transient sedative effect of coumarin. Area under the curve estimations indicate that 7-hydroxycoumarin and 7-hydroxycoumarin glucuronide distribute into brain tissue to a negligible extent if at all. The pharmacokinetic profile of C as well as the metabolic 7-hydroxylation and glucuronidation found in the blood of the gerbil is similar to that found in man. This would suggest that the gerbil is potentially a good model for pharmacokinetic and pharmacological investigations of C for correlation with human studies.

The effect of coumarin and 7-hydroxycoumarin on in vitro macrophage phagocytosis of latex particles.

The influence of various concentrations of coumarin (C) and 7-Hydroxycoumarin (7HC) upon in vitro macrophage phagocytosis of latex particles was investigated. A C dose of 20 micrograms/ml was indicated to have the greatest stimulating effect of all doses used with a percent effect of 25.6. A C dose of 80 micrograms/ml showed no apparent activity. C doses of 40, 10 and 1 microgram/ml had only a slight positive effect on phagocytosis compared to the control. 7HC concentrations of 80, 40, 20, 10 and 1 microgram/ml did not show any influence on the phagocytotic activity compared to the control. These preliminary data indicate a direct effect of C on macrophage function as has been suggested and refutes the hypothesis that 7HC is the pharmacologically active agent in reduction of high protein edemas.

Pharmacokinetics of propylthiouracil upon p.o. administration in man.

A pharmacokinetic analysis of propylthiouracil (PTU) plasma concentration versus time data for twelve euthyroid subjects was performed using the NONLIN computer program. The plasma concentration-time curves were best described by a one-compartment open model. PTU was administered to fasted subjects as a single 150-mg peroral dose. Venous blood samples were taken for a period of 8 hrs, and the concentration of unmetabolized PTU was determined by a new specific high-pressure liquid chromatographic procedure. Estimates of pharmacokinetic parameters generated in the study were compared with corresponding parameters reported in the literature.

Preliminary results on the total radioactivity distribution upon parenteral administration of 14C-coumarin to DBA/2 mice.

The time related distribution patterns of coumarin (C) and its main metabolite 7-hydroxycoumarin (7-HC) were studied in DBA/2/lac mice following retroorbital injection of 14C-labelled C. The total radioactivity was determined as counts per minute per ml or g wet weight over a period of 60 min. In blood, brain, heart, lung, muscle and spleen peak concentrations were observed 2.5 min after dosing. The liver and kidney showed the greatest accumulation with peak concentrations being reached after 10 min. Blood and brain concentrations were equal. Unmetabolized C was found in all organs studied; 7-HC was found in all organs but brain, and the glucuronide of 7-HC was found in all organs but brain and spleen. Apparently C crosses the blood brain barrier but the metabolites do not. The decay of the total radioactivity versus time appears to be best fitted to a two-compartment model for brain, heart, lung, muscle, and spleen, and to a one-compartment model for blood, liver and kidney. The terminal half-life in blood was 0.24 h.