Life Sciences Commons^™

Tooth Tissues Of Certain Sharks And Lungfishes, Yasutomo Iwai-Liao, Yoshikage Higashi, Yoshitaka Tamada

Scanning Microscopy

A comparative odontologic study was conducted on teeth and their supporting tissues from extant sharks, fossil sharks, and living lungfishes using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) X-ray microprobe to investigate evolutionary changes in tooth structure of the fishes.

No histological differences between the extant and fossil teeth of lamnoid sharks were observed. The weight percent of calcium in osteodentin of the fossil shark was higher than that in the extant shark. The weight percents of both P and Ca of tooth tissues in the giant extinct shark showed comparatively low values.

Both the upper and lower …

An Integrated Study Of The Morphological And Gross-Elemental Consequences Of Methyl Mercury Intoxication In Rats, With Particular Attention On The Cerebellum, K. Leyshon, A. J. Morgan

Scanning Microscopy

Methylmercury accumulates in the kidney and liver of rats, but fairly selectively damages the cerebellum, resulting in the clinical symptoms of neurological ataxia after prolonged exposures. Within the cerebellum, morphological examination indicated that the small granule cells beneath the Purkinje layer are especially susceptible to the toxin, showing signs of pyknosis during the phase of locomotory disability, whilst the large Purkinje cells are relatively resistant to cytotoxic injury. Flame photometric and electron probe X-ray microanalysis (EPXMA) of digested samples of the major organs failed to detect any significant changes in the Na, K, Ca, Mg, S and P concentrations of …

Hereditary Hair Changes Revealed By Analysis Of Single Hair Fibres By Scanning Electron Microscopy, B. Forslind, M. K. Andersson, E. Alsterborg

Scanning Microscopy

In many disorders with a genetic background the sparsity of scalp hairs may deter the clinician from trying to extract information from single hair fibres. Presenting a number of diverse conditions, we propose to show that simple measures can be taken in the doctor's office which makes single fibre analysis a useful tool for assessment of factors involved in genetic disorders including the integument and its appendages. The paper is focussed on the utilization of the scanning electron microscope with the goal of demonstrating that pertinent information can be gained where information from transmission electron microscopy and other techniques are …

Elemental Analysis And Fine Structure Of Mitochondrial Granules In Growth Plate Chondrocytes Studied By Electron Energy Loss Spectroscopy And Energy Dispersive X-Ray Microanalysis, Joanna Wroblewski, Romuald Wróblewski, Claudie Mory, Christian Colliex

Scanning Microscopy

Electron energy loss spectrometry - EELS, and energy dispersive X-ray microanalysis - XRMA, were used to study the elemental composition of mitochondrial dense granules - mdg. The study was performed on dry cut thin sections (80-200 nm) of freeze-dried and low temperature embedded cartilage. Results obtained by means of XRMA clearly showed high phosphorus and calcium content in the mdg. Using EELS at 100 kV primary voltage we found that small concentrations of elements (i.e. below typically 1% atomic weight) are difficult to analyze and map, this especially in sections thicker than 50-60 nm. Surprisingly, analysis of calcium can be …

Effect Of A Platinum Chemotherapy Drug On Intracellular Elements During The Cell Cycle, Using X-Ray Microanalysis, P. G. Edwards, M. D. Kendall, I. W. Morris

Scanning Microscopy

Intracellular elemental concentrations were measured in the cytoplasm, nucleus and nucleolus of cultured Chinese hamster ovary (CHO) cells, using energy dispersive electron probe X-ray microanalysis and transmission electron microscopy. Synchronous CHO cell populations were analyzed at different times during the growth cycle. The elements K, P, Mg and Zn were all more concentrated in the nucleus and nucleolus than in the cytoplasm, while no specific subcellular compartmentalization was evident for the elements Na, Cl, Ca, Fe and S. Significant changes in intracellular elemental concentrations were associated with the progression of cells from G₁ phase to S phase of the …

Elemental Mapping Of Cryosections From Cnidarian Nematocytes, Karl Zierold, Pierre Tardent, Sergey V. Buravkov

Scanning Microscopy

The distribution of elements in stinging capsules containing cells called nematocytes is shown by pseudocoloured maps representing the X-ray intensity collected from freeze-dried cryosections. This method provides a distinct overview in addition to the quantitative evaluation of single X-ray spectra. Selected examples illustrate the elemental compartmentation in various cnidarian animals. In particular the matrix of capsules in Hydra vulgaris contains high amounts of K in comparison to the tubule, the surrounding capsule wall and the cytoplasm, whereas in Actinia eguina capsules have either high concentration of Ca or Mg, the latter accompanied by S.

Copper Toxicity In Erwinia Amylovora : An X-Ray Microanalytical Study, N. Hodson, D. C. Sigee

Scanning Microscopy

The effect of Cu²⁺ ions on the growth and elemental composition of the phytopathogenic bacterium Erwinia amylovora was investigated by in vitro culture in nutrient broth supplemented with CuSO₄.

No detectable inhibition in bacterial growth occurred with medium supplemented at 10^-4M Cu (compared to control medium with no added Cu), but partial inhibition occurred at 10^-3M Cu (limiting toxicity) and complete inhibition at 10^-2M Cu.

Under conditions of limiting toxicity, incubation in Cu²⁺ ions leads to a reduction in the general synthesis of cell materials and the formation of abnormally …

Reliability Of Intracellular Water And Ion Distributions As Measured By X-Ray Microanalysis - A Review, Thomas Von Zglinicki

Scanning Microscopy

X-ray microanalysis can be an important tool to reveal the spatial relationships between polyelectrolytes, ions, and water as they occur within cells and tissues in vivo. To reach this goal, at least two of these three closely interrelated variables should be measured independently. Moreover, the absence of systematic errors should be proven.

The present review discusses the probability of artificial ion and water shifts between intracellular compartments due to the growth of dendritic ice crystals much larger than the cross-sectioned remnants commonly seen in frozen-dried sections. Considering the possible mechanism of ice crystal growth it is concluded that ions and …

Cryopreparation Of Tissue For Clinical Applications Of X-Ray Microanalysis, Godfried M. Roomans

Scanning Microscopy

A number of diseases is associated with changes in ion and/or water distribution at the tissue or cell level, and X-ray microanalysis can be used to investigate the relationship between the disease process and the changes in elemental distribution. For analysis of diffusible elements by X-ray microanalysis, the tissue has to be prepared by cryotechniques. To carry out studies of this kind in a clinical environment poses a number of problems. Some of these problems occur already before the tissue is frozen, others are caused by the practical and ethical limitations that are imposed on the freezing method itself when …