Mitotic and nonmitotic multiple-layered perfusion cultures.

Cell types in addition to those previously described (Kruse et al. 1963. J. Nat. Cancer Inst. 31:109; Kruse and Miedema. 1965. J. Cell Biol. 27:273) were found to form multiple-layered cultures by perfusion-culture technique. Dense populations containing 43 x 10(6) embryonic rat muscle (NF-ER) cells, 23 x 10(6) diploid human tonsillar (NF-JAM) cells, 77 x 10(6) human pleural effusion isolate (RPMI 2650) cells, 35 x 10(6) embryonic diploid human lung (Flow 2000) cells, 21 x 10(6) bovine lung (FB4BM) cells, 108 x 10(6) bat lung (Tb1Lu) cells, and 81 x 10(6) SV-40 virus-transformed embryonic diploid human lung (WI-38VA13A) cells were obtained in 6-14 days from dilute inocula in T-60 or T-75 flasks; these were equivalent to about 4, 3, 3, 4, 2, 4, and eight monolayers, respectively. Perfusion of an NF-ER culture for 6 wk with medium plus 10% whole calf serum yielded a cell density equivalent to 12 monolayers (140 x 10(6) cells per T-75 flask). This culture exhibited random labeling of nuclei from bottom to top after pulsing for 90 min with thymidine-(3)H. Medium plus 0.1% serum maintained NF-JAM cultures at constant viable cell numbers with virtual absence of thymidine-(3)H labeling. Similar results were obtained with WI-38 cultures, but WI-38VA13A cells continued active DNA synthesis and mitosis in medium with 0.1% serum to form 16-20 layers of cells (191-239 x 10(6) cells per T-75 flask) in 27 days. WI-38VA13A cells ceased proliferation and became nonviable rapidly in serumless medium.

The effect of GaAs(100) surface preparation on the growth of nanowires.

The influence of GaAs(100) substrate surface preparation on Au-catalysed GaAs nanowires was studied. Elongated pits of varying dimensions and orientation were formed on GaAs(100) substrates depending on the interaction with Au and surface oxides. The resulting surface topography is shown to influence the density and orientation of nanowires. [111] B-oriented nanowires nucleated from Au particles lying on the sidewall facets of the pits, while [011]-oriented nanowires nucleated from Au particles lying outside the pits.

Recrystallization of tungsten wire for fabrication of sharp and stable nanoprobe and field-emitter tips.

Atomically sharp tungsten tips made from single crystal tungsten wire are superior to those made from cold-drawn polycrystalline wire but are rarely used due to their high price. We have devised a method of obtaining highly crystalline tungsten wire by recrystallizing cold-drawn wire. The effect of various heat treatments on the wire microstructure was observed using scanning electron microscopy and x-ray diffraction. A dramatic difference in the shapes of tips etched from cold-drawn and recrystallized wires was observed using transmission electron microscopy. The described annealing process is an inexpensive alternative to using single crystal wires.

Determination of the mean inner potential in III-V semiconductors, Si and Ge by density functional theory and electron holography.

The mean inner potentials of various III-V semiconductors, Si and Ge have been calculated by density functional theory methods. For that purpose, the Coulomb potential of slabs consisting of a crystal and vacuum region has been computed and averaged inside the crystal region. The computed values are in agreement with experimental values obtained by electron holography for Si and GaAs. For the other semiconductors, the deviations are smaller than 0.8 V. The results from density functional theory are approximately 10% smaller than the values derived from atomic scattering factors computed by Hartree Fock calculations.

Minor role of oxidative stress during intermediate phase of acute pancreatitis in rats.

Reactive oxygen species have been implicated in the pathogenesis of acute pancreatitis. Few studies have focused on the loss of endogenous antioxidants and molecular oxidative damage. Two acute pancreatitis models in rats; taurocholate (3% intraductal infusion) and cerulein (10 microg/kg/h), were used to study markers of oxidative stress: Glutathione, ascorbic acid, and their oxidized forms (glutathione disulfide and dehydroascorbic acid), malondialdehyde, and 4-hydroxynoneal in plasma and pancreas, as well as 7-hydro-8-oxo-2'-deoxyguanosine in pancreas. In both models, pancreatic glutathione depleted by 36-46% and pancreatic ascorbic acid depleted by 36-40% (p <.05). In the taurocholate model, plasma glutathione was depleted by 34% (p <.05), but there were no significant changes in plasma ascorbic acid or in plasma and pancreas dehydroascorbic acid, malondialdehyde, and 4-hydroxynoneal, and no significant changes in the pancreas glutathione disulfide/glutathione ratio. While pancreas glutathione disulfide/glutathione ratio increased in the cerulein model, there were no significant changes in plasma glutathione, plasma, or pancreas ascorbic acid, dehydroascorbic acid, 4-hydroxynoneal, and malondialdehyde, or in pancreas 7-hydro-8-oxo-2'-deoxyguanosine. Reactive oxygen species have a minor role in the intermediate stages of pancreatitis models.

Anomalous mobility of strongly bound surface species: Cl on GaAs(001)-c(8 x 2)

Although strongly bound chemisorbates at low coverage readily diffuse on metal surfaces at 300 K, they generally do not diffuse on semiconductor surfaces because of a large corrugation in the adsorbate-surface interaction potential. Chlorine chemisorbed on the Ga-rich GaAs(001)-c(8x2) surface has anomalously fast diffusion even though the chemisorption state is tightly bound and highly specific. Simple Hartree-Fock total energy calculations suggest that this diffusion of strongly bound adsorbates can occur at 300 K because there are multiple nearly degenerate adsorbate sites.

beta-Blockade used in precision sports: effect on pistol shooting performance.

In a double-blind cross-over study of 33 marksmen (standard pistol, 25 m) the adrenergic beta 1-receptor blocker, metoprolol, was compared to placebo. Metoprolol obviously improved the pistol shooting performance compared with placebo. Shooting improved by 13.4% of possible improvement (i.e., 600 points minus actual points obtained) as an average (SE = 4%, 2P less than 0.002). The most skilled athletes demonstrated the clearest metoprolol improvement. We found no correlation between the shooting improvement and changes in the cardiovascular variables (i.e., changes of heart rate and systolic blood pressure) and no correlation to the estimated maximum O2 uptake. The shooting improvement is an effect of metoprolol on hand tremor. Emotional increase of heart rate and systolic blood pressure seem to be a beta 1-receptor phenomenon.

Direction and frequency specific processing in the perception of long-range apparent movement.

The presentation of repetitive apparent movement (AM) produces the illusion of smooth sinusoidal movement. During prolonged observation this impression vanishes periodically. On the basis of these observations, it was postulated that such long-range AM are processed via direction and frequency specific subsystems. This hypothesis was examined by means of selective adaptation. A bi-stable movement display was used to measure the adaptation effect. Generally a frequency specific reaction for horizontal and vertical movement was verifiable. In addition to this, the existence of the presumed narrow-band processing channels was confirmed by the tuning curves determined. The significance of the results for AM perception and their applicability to the processing of real movement Gestalt will be discussed.

Determination of the mean inner potential in III-V semiconductors by electron holography.

The mean inner potential of GaAs(14.18V), InAs(14.50V), GaP(14.35V) and InP(14.50V) has been measured by transmission electron holography using the phase shift of the (000)-beam of the first hologram sideband. To provide a defined specimen geometry we used 90 degrees wedges obtained by the cleavage technique. The exact excitation condition as well as the acceleration voltage of the electrons were determined from convergent beam electron diffraction images. The magnification is extracted from two-beam lattice fringe images and dynamical effects are taken into account by Bloch-wave calculations.

Frontal gamma-band enhancement during multistable visual perception.

The aim of our study was to find out whether an increase in the gamma band may be related to the reversal phase during viewing of an ambiguous pattern. The present study describes the significant gamma band (30-50 Hz) activity increase in EEG during states of perceptual switching (reversal state). In our experiments the multistability was induced with an ambiguous stimulus pattern, known as stroboscopic alternative motion (SAM). The investigations carried out in 11 subjects included a measuring strategy with three different experimental conditions: (1) recording of spontaneous EEG as baseline; (2) recording of the EEG during naive observation of the ambiguous pattern; (3) recording of EEG during active observation of SAM. The results indicate that the multistable perception is one of the multifold cognitive processes giving rise to 40 Hz enhancement in the entire cortex. The most significant 40 Hz enhancements were measured in frontal areas and can reach increases of 40 to 50% in states of naive and active observations of SAM, respectively, in comparison to spontaneous EEG recordings. The results indicate that the increase of frontal gamma band is related to the destabilization of the perceptual system when viewing multistable patterns.

Opioid involvement in the perception of pain due to endurance exercise in trained man.

The purpose of this study was to evaluate the role of endogenous opiates in modulating physical performance during dynamic exercise in conscious man. The plasma concentration of beta-endorphin (BEP) and of adrenocorticotropic hormone (ACTH) along with muscle pain (McGuill Pain Questionnaire) were assessed in 17 trained, male runners before and after running the longest possible distance within 12 min (i.e., the Cooper test). Each runner participated twice in the test (double-blind cross-over design), with a 1-week interval--with or without an injection of the opiate antagonist naloxone (0.8 mg i.v.). The average (SEM) distance reached was 3,198 (45) m in the naloxone test and 3,240 (38) m in the placebo test. The BEP increased significantly during the tests by a factor of 4.1 on naloxone and by 2.8 on placebo (from the normal resting averages of 1.7 and 2.1 pmol/l, respectively). The ACTH also increased significantly by a factor of 2.0 on naloxone and 2.5 on placebo (from the normal resting averages of 19.3 and 16.8 pmol/l, respectively). There were no significant differences between the naloxone and the placebo test with respect to the increments of BEP or ACTH by exercise. However, the perception of muscle pain was enhanced with naloxone. The increased perception of pain did not decrease the athletes ability to perform in terms of the distance run. We conclude that endogenous opiates are involved in the perception of pain associated with exhaustive exercise and may subserve psychological rather than physiological functions during exercise.

The parasitemia of cloned Trypanoplasma borreli Laveran and Mesnil, 1901, in laboratory-infected common carp (Cyprinus carpio L.).

The course of parasitemia of cloned Trypanoplasma borreli in laboratory-infected common carp was investigated. In 25-42-g carp kept at 20 C, the prepatent period was 8 days; after a phase of exponential growth, the parasitemia peaked at day 39 postinjection (PI) at a level of about 10(3) T. borreli/microliters blood. This maximum was followed by a chronic phase of about 6 wk with large numbers of T. borreli. At 20 wk PI, T. borreli was absent in infected carp. In 2.2-g carp kept at 20 C, the prepatent period was 4 days only, and the parasitemia peaked at day 23 PI. At 30 C, T. borreli was present in the blood only for 12 wk, and the number of T. borreli did not exceed 162 trypanoplasms/microliters blood. Carp kept at 8 and 15 C showed retarded development of parasitemia. The prepatent period lasted longer and the generation time was increased, but the level of parasitemia was not affected. Carp, inoculated at 8 C and then warmed to 20 C on days 27 and 55 PI, developed a parasitemia of 10(4) flagellates/microliters blood and showed high mortalities. During the prepatent period, T. borreli was found in the muscle tissue of the inoculation area but in no other tissue. In the kidney, T. borreli was found 27 hr PI, whereas in the circulating blood it was manifest at day 3 PI. At the same time it was manifest in the liver and spleen.

Development of Trypanoplasma borreli (Mastigophora: Kinetoplastida) in the leech vector Piscicola geometra and its infectivity for the common carp, Cyprinus carpio.

The development of Trypanoplasma borreli in the crop of the leech vector Piscicola geometra was characterized by significant changes in morphology. Immediately after ingestion by the leech, stumpy-shaped T. borreli predominated and numerous dividing specimens were found. This led to long and slender trypanoplasms near the end of the infection. The infection was terminated with complete digestion of the blood stored in the crop of the leech. The longest period of infection observed was 11 days. Trypanoplasma borreli was found only in the crop of the leech. At any time during the infection, T. borreli isolated from P. geometra cause a parasitemia when inoculated into parasite-free carp. There was no difference in morphology or infectivity among T. borreli isolated from various crop regions of P. geometra.

[Splenic rupture--a skateboard accident]. / Miltruptur--en rullebraetulykke.

A 13-year-old boy presented with persisting abdominal pain after a skateboard accident. Primary clinical and laboratory findings disclosed no signs of intra abdominal bleeding. Ultrasound scanning indicated rupture of the spleen which was confirmed by acute exploratory laparotomy.

[CD-ROM--a useful tool for physicians]. / CD-ROM--et nyttigt redskab for laeger.

The use of compact disc read-only-memory (CD-ROM) at a medical library is described. The introduction of CD-ROM as a reference tool has been a positive experience both for the library staff and the end users (doctors). Medical journals in fulltext, textbooks and special databases are already available on CD-Rom. Future perspectives concerning CD-technology for doctors are discussed.

[Upper abdominal pain and pre-eclampsia--HELLP syndrome]. / Ovre abdominalsmerter og praeeklampsi--HELLP-syndrom.

A 26 year old primiparous woman in the 30th gestational week presented with upper right abdominal pain. Clinical examination revealed direct tenderness under the right curverture, oedema, hypertension and proteinuria. Ultrasound scanning showed a normal gallbladder. Laboratory findings revealed Hemolysis, Elevated Liver enzymes and Low Platelet count. On account of suspected HELLP-syndrome cesarean section was performed. We suggest screening of all pregnant with upper abdominal symptoms suspected for preeclampsia by measuring platelet count and liver enzymes.

Note: benign and reproducible preparation of titanium tips.

Fabrication of titanium tips via electrochemical etching is commonly hindered by the formation of a tough oxide layer. A new one-step approach based on dc etching in a non-aqueous electrolyte is presented. The electrochemical tip etching was carried out at 20 V in a benign etchant of 1M NaCl in ethylene glycol. Tip radii below 100 nm are demonstrated using current cut-off control and approaching 150 nm without cut-off control. The simplicity and efficiency of the approach eliminates pre and post electropolishing steps due to the electropolishing capability of a NaCl-ethylene glycol based electrolyte.

Note: electrochemical etching of silver tips in concentrated sulfuric acid.

Sharp metal tips have many uses, including in scanning probe microscopy. Silver is a particularly interesting metal for plasmonic enhancement, e.g., in tip-enhanced Raman spectroscopy, however few methods for the production of silver tips have been explored. A simple and reliable one step dc electrochemical method for the production of sharp silver tips in concentrated H2SO4 is presented. The optimal conditions are 10 V cell voltage and 99% sulfuric acid for tip radii below 100 nm. A LabView program was written to control the cut-off of the circuit to within a millisecond to avoid blunting the tips after drop-off.