Rolf Odselius

Energy-dispersive X-ray microanalysis of the bone mineral content in human trabecular bone: A comparison with ICPES and neutron activation analysis

To evaluate the accuracy of bone mineral composition determination by electron microprobe analysis (EDX) the measurements have been compared to instrumental neutron activation analysis (INAA) and chemical analysis (ICPES). Bone specimens from five femoral heads were used. The trabecular content of calcium (Ca) and phosphorus (P) was analyzed by the three different methods. The FDX method allows for a microstructural analysis of intact, methylmetacrylate-embedded, undecalcified bone and the measuring points can thus be distinctly identified centrally in each trabecula. The analysis yielded 25.8±0.7 wt% Ca and 10.5±0.1 wt % P, compared with 22.2±0.5 and 23.0±1.0 wt % Ca, and 9.83±0.21 and 10.02±0.44 wt % P for INAA and ICPES, respectively. The EDX analysis was calibrated by consecutive measurements of a hard, pressed tablet of hydroxyapatit of known content. The mean Ca content deviated with-0.38 wt % from the given content and P with-0.89 wt %. We could not verify any particular interference from the embedding procedure, however, it is possible that the relatively lower P content still may reflect this. The magnesium (Mg) concentration was 0.31±0.02 wt % by EDX and 0.26±0.02 wt % by INAA. The EDX analytical method provides a useful tool for simultaneous elemental quantification in bone. It has the advantage of permitting the use of cation bone biopsy material and thus allowing for a unique microstructural evaluation of the degree of mineralization. By comparison with other established methods, the assessment of accuracy and reliability indicates that the measurements are well in range for the major constituents, Ca and P, whereas INAA is more sensitive in determining trace elements.

Neuronal connectivity patterns in the compound eyes of Artemia salina and Daphnia magna (Crustacea: Branchiopoda)

SummaryThe neuronal types and patterns in the visual system of the species Artemia salina and Daphina magna have been studied with the Golgi method and electron microscopy. The lamina contains five classes of neurons: photoreceptor axons, monopolar, centrifugal, tangential and amacrine neurons. The terminals of the receptor axons are distributed in two (A. salina) or three (D. magna) layers. The dilated terminals have an extensive and wide array of fine branches. One axon from each ommatidium bypasses the lamina and terminates in the medulla in A. salina. A. salina has four types of monopolar neurons, two of which are stratified, whereas in D. magna only two types are found, one of which is bistratified. Tangential T-neurons connect the lamina with the protocerebrum. D. magna has in addition one tangential T-neuron connecting both the lamina and the medulla with the protocerebrum. In both species monopolar-type centrifugal neurons connect the medulla and the lamina, whereas that of A. salina has a wide laminar distribution. Both species also have amacrine cells in the lamina. The medulla contains, besides those shared with the lamina, transmedullary neurons (two types in A. salina), amacrine cells and neurons originating in the protocerebrum.“Cartridge”-type synaptic compartments are lacking in the investigated species, although a periodic arrangement is discernible in the distal portion of the lamina of A. salina. The receptors from three types of specialized contacts in Artemia, one of which involves a dyad. D. magna has only one-to-one synapses. Neurosecretory fibres are absent in A. salina.

The basement membrane of the insect and crustacean compound eye: definition, fine structure and comparative morphology

SummaryThe basement membrane of the compound eye of four insect species and three crustacean species was investigated employing electron microscopy. The basement membrane consists of an extracellular (basal lamina) and a cellular portion, the latter being composed of the flattened terminal extensions of cone cells and accessory pigment cells in insects and distal pigment cells in crustaceans. Other cells can also contribute to the basement membrane. It is thus a complex structure in all well-developed compound eyes. The cellular contributions vary in different species and were found to correlate to specific taxonomic units.

A new mechanism for light-dark adaptation in theArtemia compound eye (Anostraca, Crustacea)

SummaryThe apposition compound eye ofArtemia sp. (a brine shrimp) has a glycogen lens inside the crystalline cone. Owing to the absence of a corneal lens, the glycogen lens is solely responsible for the focusing on the rhabdom tip. Examination of the light-dark adaptation mechanism revealed the following:1.No pigment migration and only small changes in the palisade.2.A slight increase in diameter of the distal part of the rhabdom during dark adaptation.3.A pronounced shortening of the cone during dark adaptation, resulting in a reduced distance between the glycogen lens and the rhabdom.4.Simultaneous with (3), the glycogen lens elongates as the radii of curvature of the refracting surfaces decrease. A careful optical investigation of the adaptational mechanism demonstrated perfectly focused ommatidia irrespective of the adaptational length of the cone. The refocusing is performed by the curvature change of the glycogen lens. This results in a change in focal length of the system, and thus an adjustable acceptance angle. The change in rhabdom diameter increases the change in the acceptance angle.The optics of ommatidia in different parts of the eye was analysed in order to evaluate the extent of regional differences.A method for refractive index measurements in living cells, including viability tests, is described, and the importance of suitable immersion media is discussed.

The compound eye of Leptodora kindtii (Cladocera). An adaptation to planktonic life.

SummaryEach of the approximately 500 ommatidia in the compound eye of the cladoceran crustacean Leptodora kindtii has a crystalline cone consisting of five cells. Five retinula cells are also present, one of which contributes to the distal 1–2 μm of the rhabdom only; the other four retinula cells form a continuous rhabdom. Throughout the rhabdom its cross section displays two separate halves with the axis of the microvilli in one half perpendicular to that in the other (orthogonal pattern). Interferometric analysis of the refractive index of the crystalline cone revealed an inhomogeneous system with one distal and one proximal gradient. The gradient system was found to exclude rays entering from adjacent facets, thus maintaining the optical isolation. Consequently, these optics replace distal screening pigment, which is absent in the eye. The long and unscreened crystalline cones give rise to an almost transparent eye in conformity with the overall transparency of this planktonic animal.The morphological characteristics of the eye of this species deviate from other cladoceran eyes, but the optical design closely resembles that of some pelagic marine amphipod crustaceans.

The concentration of calcium and phosphorus in trabecular bone from the iliac crest

SummaryThe concentrations of calcium and phosphorus were determined in central parts of bone trabeculae in the human iliac crest by means of an energy dispersive microanalysis technique. Two age groups, each consisting of six suddenly diseased male subjects, were investigated. It was found that the concentrations of calcium and phosphorus did not differ between young and old men. The obtained mean values were fairly alike and determined to 40 and 17 weight %, respectively.

Electron microprobe investigation of calcium and phosphorus concentration in human bone trabeculae—Both normal and in posttraumatic osteopenia

SummaryWith electron probe microanalysis the concentration of calcium and phosphorus was determined in central parts of tibia epiphyseal bone. Trabeculae from five men who had had a fracture of the ipsilateral tibia diaphysis were analyzed. The results were compared with those of five men who had suffered sudden death. There was an even distribution of calcium in the control cases: the mean value was 45±1 wt%. In the posttraumatic group of patients there was a lower mean and a greater scatter: 29±10 wt%. Also, the concentration of phosphorus was lower in the posttraumatic cases as compared with the cadavers.

Phospholipid impregnation of abdominal rubber drains : resistance to bacterial adherence but no effect on drain-induced bacterial translocation

In order to evaluate the effect of surface modification of biomaterials on bacterial adherence and bacterial translocation after intraperitoneal biomaterial implantation, phosphatidylcholine- or phosphatidylinositol-impregnated rubber drain pieces, which had been intraperitoneally implanted in the rat for 2 and 7 days, or unimplanted, were incubated in vitro with3H-labelledEscherichia coli andEnterobacter cloacae. As compared with unimpregnated pieces, the adherence of bacteria significantly decreased to phosphatidylcholine- and phosphatidylinositol-impregnated rubber drain pieces that were either unimplanted or implanted for 2 days, but not for 7 days. The supplementation of albumin in the medium reduced the adherence of bacteria to the unimplanted, unimpregnated drain pieces, but did not further decrease adherence of bacteria to the unimplanted, phospholipid-impregnated brain pieces. Bacterial growth was inhibited after incubation in nutrient broth supplemented with phospholipids. The incidence of enteric bacterial translocation induced by intraperitoneal drain implantation did not differ between phospholipid-impregnated and unimpregnated drain pieces. Scanning electron microscopy revealed a large amount of biofilm and fibrous deposition on the surface of the implanted, phospholipid-impregnated rubber drain pieces. Thus, phospholipid impregnation of rubber drains reduces bacterial adherence and inhibits bacterial growth, without influencing the incidence of bacterial translocation.

Electron Microprobe Analysis and Histochemical Examination of the Calcium Distribution in Human Bone Trabeculae: A Methodological Study Using Biopsy Specimens from Post-Traumatic Osteopenia

Energy dispersive X-ray microanalysis (EDX) (or electron microprobe analysis) of the relative intensity for calcium in different bone trabeculae from the tibia epiphysis, and in different parts of one and the same trabecula, was performed on 3 patients who had earlier had a fracture of the ipsilateral tibia-diaphysis. The variation in intensity was compared with the histochemical patterns obtained with both the Goldner and the von Kóssa staining techniques for detecting calcium in tissues. Previously reported calcium distribution features, found to be typical for posttraumatic osteopenia, such as striated mineralization patterns in individual trabeculae and large differences in mineralization level between different trabeculae, could be verified both by means of the two histochemical procedures and from the electron microprobe analysis. A pronounced difference was observed, however, between the two histochemical staining techniques as regards their sensitivity to detect calcium. The two methods have different turnover points, from negative to positive along a gradient change of calcium concentrations. To judge from the values obtained from the EDX measurements, the sensitivity of the Goldner technique should be more than ten times higher than that of von Kóssa. The EDX measurements gave more detailed information than either of the two histochemical techniques: great variations in the intensity of the calcium peak were found in trabeculae stained as unmineralized as well as mineralized.

Presence of calcium in polychaete cortical granules demonstrated by X-ray microanalysis on ultrathin cryo-sections of oocytes and eggs

SummaryCortical granules from fertilized eggs, oocytes and nurse cells of Ophryotrocha labronica have been analyzed for the presence of calcium using cryo-ultramicrotomy and X-ray microprobe analysis. All cortical granules showed a significant peak for calcium, but yolk granules were without calcium. These results support the hypothesis that the discharge of cortical granules shortly after fertilization is a self-propagating phenomenon involving the diffusion of Ca2+ from bursting granules.