Combined Light Microscope Research Articles

Revised taxonomy and early evolution of fasciculiths at the Danian–Selandian transition

Abstract. We present a taxonomic revision of the family Fasciculithaceae focused on forms that characterize the early evolution of this family group, which are currently included within the genera Gomphiolithus, Diantholitha, Lithoptychius and Fasciculithus. The investigation approach is based on a combined light microscope (LM) and scanning electron microscope (SEM) analysis of specimens from well-preserved ODP–DSDP site material (ODP Site 1209; Site 1262; ODP Site 1267; DSDP Site 356; DSDP Site 119) and outcrops (Bottaccione and Contessa, Italy; Qreiya, Egypt) across the Danian–Selandian transition. The direct LM–SEM comparison of the same individual specimen provides clarification of several taxa that were previously described only with the LM. One new genus (Tectulithus), five new combinations (Tectulithus janii, Tectulithus merloti, Tectulithus pileatus, Tectulithus stegastos and Tectulithus stonehengei) and six new species are defined (Diantholitha pilula, Diantholitha toquea, Lithoptychius galeottii, Lithoptychius maioranoae, Tectulithus pagodiformis and Fasciculithus realeae). The main characteristics useful to identify fasciculiths with the LM are provided, together with a 3D–2D drawing showing the main structural features. The accurate taxonomic characterization grants the development of an evolutionary lineage that documents a great fasciculith diversification during the late Danian and early Selandian. Four different well-constrained events have been documented: the lowest occurrence (LO) of Gomphiolithus, the paracme of Fasciculithaceae at the top of Chron C27r (PTC27r), the radiation of Diantholitha (LO Diantholitha), the paracme of Fasciculithaceae at the base of Chron C26r (PBC26r), the radiation of Lithoptychius (LO Lithoptychius) and the radiation of Tectulithus (lowest common occurrence of Tectulithus) that shows the biostratigraphic relevance of this group across the Danian–Selandian transition.

Design, Rheology and Physicochemical Characterizations of Oil-in-water Emulsions Stabilized by Waxy Starch Derivatives

Simple emulsions (o/w) stabilized by octenyl succinic anhydrous (OSA) starch were studied. They were characterized by the evaluation of the rheological and physicochemical properties and, the observation under the light microscope in combination with granulometric analysis after formulation. The obtained results demonstrated the effects of the amount of OSA starch on the variation of the diameter of particles, stability of emulsions and their rheological behavior. The best characteristics were found in the emulsion with a ratio 40/60 (o/w) at high OSA starch concentration, because the substitution of the oil phase by the network created by the chains of the modified polysaccharides which could be the major factor in stabilisation of emulsions.

Effect of a rapidly resorbable calcium alkali phosphate bone grafting material on bone formation and osteogenic marker expression after sinus floor augmentation in humans

Event Abstract Back to Event Effect of a rapidly resorbable calcium alkali phosphate bone grafting material on bone formation and osteogenic marker expression after sinus floor augmentation in humans Christine Knabe-Ducheyne1*, Tom Knauf1*, Barbara Peleska2*, Georg Berger3*, Renate Gildenhaar3, Cynthia Wirth3*, Alexander Rack4, Wolf-Dietrich Huebner5 and Michael Stiller1 1 Philipps-University Marburg, Dept. of Experimental Orofacial Medicine, Germany 2 Philipps University Marburg, Department of Prosthodontics, Germany 3 Federal Institute for Materials Research and Testing, Division “Ceramic processing and biomaterials”, Germany 4 European Synchrotron Radiation Facility, Structure of Materials Group, France 5 Curasan AG, Division of Clinical Studies, Germany Introduction: Sinus floor augmentation (SFA) has become a well-established pre-implantology procedure for alveolar ridge augmentation of the posterior maxilla[1]. Using synthetic biodegradable bone substitutes avoids second-site surgery for autograft harvesting[1]. Compared to the bone substitutes which are currently clinically available, there is a significant need for bone substitutes which degrade more rapidly, but still stimulate osteogenesis at the same time. This has led to the development of bioactive, rapidly resorbable calcium alkali orthophosphate (CAP) materials[1]. Previously, we were able to show that a silica containing CAP GB9 (Si-CAP) had a greater stimulatory effect on osteoblast differentiation and bone formation in vitro and in vivo after alveolar ridge augmentation in a sheep, when compared to the clinically established materials tricalcium phosphate (TCP) and bioactive glass 45S5[1]. This effect was associated with simultaneous enhanced activation of the ERK differentiation, the PI3K cell survival as well as of the alternate p38 pathways[2], and was in addition to exhibiting a greater biodegradability. In the current study, the biodegradability and effect of this Si-CAP on osteogenesis was evaluated in biopsies sampled 6 months after SFA and compared to that of TCP. Methods: The study consisted of 38 patients (22 women,16 men) ranging in age from 54-69 years. In all patients SFA was required in order to facilitate dental implant placement. Test materials were: first, granules with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing sodium magnesium silicate (Si-CAP) (porosity 75%, grain size 1000 to 2000 µm; Osseolive™,Curasan AG, Germany). Second, ß-TCP granules (porosity 65%, grain size 700 to 1400 µm, Ceros™; Mathys Inc., Switzerland). SFA was performed using a combination (10:1 ratio) of Si-CAP or TCP granules and autogenous bone chips. At implant surgery, 6 months after SFA, when preparing the implant bed, cylindrical biopsies, 2.5 mm in diameter and 10 mm long, were sampled using a trephine drill. The samples were processed utilizing a technique which facilitated performing immunohistochemical analysis on hard tissue sections[3],[4] using primary antibodies specific to collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). First, histomorphometric evaluation of the sections was performed. To this end, a rectangular area 2 mm2 in size was defined in each section at a distance of 3 mm from the native alveolar crest, i.e. centrally, as well as apically just underneath the Schneiderian membrane. The bone area fraction, the graft material area fraction and the bone-biomaterial-contact were measured in both areas using a light microscope in combination with a digital camera (DP73) and Cellsens software (Olympus, Germany).[3][4] Second, semi-quantitative analysis of the immunohistochemical staining was performed. A scoring system quantified the amount of staining observed using light microscopy. A score of (+++), (++) and (+) corresponded to strong, moderate or mild, whereas a score of (0) correlated with no staining[4],[5]. Results: Both materials facilitated bone formation and matrix mineralization, which were still actively progressing from the sinus floor in an apical direction 6 months after SFA. Bone formation, the bone-biomaterial-contact, i.e. bone-bonding, and particle degradation were greater, i.e. more advanced, with the Si-CAP grafting material compared to TCP, both in the apical (Fig. 1) as well as in the central region. This was accompanied by greater expression of Col I, BSP and OC in the newly formed bone tissue in the Si-CAP samples compared to TCP. Fig. 1. Bone area fraction, particle area fraction and bone-biomaterial- contact in the apical region of biopsies sampled 6 months after SFA. Discussion and Conclusions: Six months after implantation Si-CPA facilitated greater bone formation and biodegradability than the TCP graft material, whose excellent osteoconductive properties have been widely documented[1],[4],[5]. Consequently, Si-CAP can be regarded as excellent grafting material for SFA in a clinical setting. The authors would like to thank Ms. A. Kopp for her excellent technical assistance.

Pulse-mode scanning ion conductance microscopy—a method to investigate cultured hippocampal cells

Scanning ion conductance microscopy (SICM) takes advantage of the increase in the resistance which occurs if a glass microelectrode is closely approached to a poorly conducting membrane (Science 243 (1989) 641) and has been shown to be a promising technique to study membranes of living cells (Biophys J 73 (1997a) 653; J Microsc 188 (1997b) 17). Based on a newly designed set-up on top of an inverted light microscope in combination with a speed optimized low noise intracellular amplifier, a novel mode for control of the distance between the probe and surface has been developed. By application of current pulses, the change in the resistance is monitored independently from electrode drift and parasitic DC currents. We demonstrate the applicability by showing first high-resolution images of neural cells produced with the pulse-mode operated SICM.

A Continuous Measurement of Swelling of Rice Starch During Heating

Abstract The changes in size distribution of rice starch granules during heating have been determined continuously using a polarised light microscope in combination with a hot stage and an image analysis system. The size of starch granules increased slightly as the temperature was raised from 35°C to 55°C, with a 3·9% increase in average area; however, a dramatic increase in size of starch granules occurred at 65°C. The swelling of the starch granules reached a maximum 54·7% increase in average area at 75°C which is coincidental with the peak temperature ( T p ) of DSC thermograms. Starch granules proceeded to disrupt/dissolve above 75°C. Loss of birefringence occurred at a lower temperature than granule rupture. T p appeared to be the critical point in the phase change between the stages of swelling and disruption/dissolution of rice starch granules during heating.

Correlation of histology and acoustic parameters of liver tissue on a microscopic scale

The correlation of several acoustic parameters with histological features was investigated in healthy White New Zealander rabbit liver ( n = 10). Thin sections (10 μm) were studied by means of a light microscope in combination with a digital image processing system. Adjacent thick sections (250μm) were studied by means of a custom-designed acoustic microscope. Markers of black silk suture material, that could be identified both optically and acoustically, enabled the spatial correlation of both imaging modalities. Acoustic images were reconstructed from the velocity of ultrasound, the attenuation at the central frequency (30 MHz), the attenuation spectral slope, the backscatter spectral slope and the backscatter at the central frequency. The measurements comprised the frequency range from 10 to 50 MHz, yielding a resolution of approximately 50 μm. From the thin sections (10μm) the local histological composition was obtained by digital segmentation techniques. The features that were segmented are: the collagen rich fibrous tissue content, the area lumina, the area interstitial spaces, the number density of nuclei and the area parenchymal tissue. Correlation techniques revealed that the main feature responsible for attenuation is collagen. There was a fair correlation between area lumina and attenuation, but this was caused by a high correlation between the collagen that surrounds the lumina, and attenuation. No correlation was found between any histological feature and backscatter parameters or velocity.

An Estimate of the Mean Length of Collagen Fibrils in Rat Tail-Tendon as a Function of age

A theoretical expression has been derived for the mean collagen fibril length in tendon based on the assumption that collagen fibrils originate in cell surface invaginations and terminate either at some remote cell surface or another collagen fibril bundle. The expression thus determined requires knowledge of the effective lengths of the fibrocytes (or fibrocyte assemblies) and the cellular content of the tendon. Both of these parameters have been measured experimentally as a function of age for rat-tail tendon using a combined light microscope and electron microscope approach. The results obtained for immature tendon suggest that the mean collagen fibril length is at least equal to the critical length required to maintain the appropriate tensile properties. In the most mature tissue studied, however, the mean-collagen fibril length is in excess of 100 times the critical length.

Optical imaging of magnetic domains in motion (invited)

We describe a laser magneto-optic microscope (LAMOM) system, used to observe magnetic domain dynamics in Permalloy thin-film devices. Optimization of Kerr magneto-optic contrast is achieved by using laser illumination in a polarized light microscope in combination with video image processing. High magnetic contrast, a diffraction-limited (0.25 μm) resolution, and motion picture recording capability at up to 30 frames/s are demonstrated by recent results.

Confirmation of gravisensitivity in the slime mold physarum polycephalum under near weightlessness

We have investigated Physarum polycephalum, a unicellular organism with no special gravity receptors, on its ability to react to gravity. The first experiments were 0 g-simulation experiments on the fast-rotating clinostat conducted with plasmodial strands of this acellular slime mold. In these earth-bound experiments the observed parameters were periodicity of the contractions and dilatations of the strand's ectoplasm as well as the periodicity and velocity of the striking cytoplasmic (endoplasmic) shuttle streaming. During 0 g-simulation these parameters showed significant changes indicating the existence of a gravisensitivity of the slime mold. The Space-Shuttle experiment (ESA-Biorack in D 1-Mission) should demonstrate the validity of the 0 g-simulation on the fast-rotating clinostat. The experiment was designed in a way enabling the registration of the same parameters as on the clinostat (using the light microscope in combination with a photo diode and a cinecamera). Only one of the two planned measurement sessions was fully successful and provided us with data confirming the results gained on the fast-rotating clinostat: The slime mold showed under real near weightlessness in the D 1-Space Shuttle Mission a transient frequency increase in its contraction rhythmicity and a (steady) increase in the streaming velocity of its endoplasm.

Combined light microscope and scanning electron microscope, a new instrument for cell biology

An instrument for combined scanning electron microscopy and light microscopy is described. This microscope comprises a scanning electron microscope (SEM) with a special stage in the vacuum chamber incorporating light microscope (LM) optics (objective and condensor) designed for transmission and fluorescence light microscopy. This SEM is connected with the LM by an optical bridge. A photometer unit is also attached. Since the specimen in the vacuum chamber can be studied simultaneously by both kinds of microscopy, the combination permits the study of various parameters of cell-surface structures with SEM and the cell cycle by DNA microfluorometry.