Preliminary report of spinal cord injuries resulting from inappropriate microchip implantation in two puppies

Since the revised Animal Welfare and Management Law in Japan became effective on June 1st, 2022, it became mandatory for pet dogs and cats to have microchips implanted and registered prior to be sold. Two cases of spinal cord injury as the result of inappropriate microchip implantation in puppies were referred to our facility, of which were diagnosed by cervical spinal radiography and computed tomography (CT). While adverse reactions following microchip implantation are rare, the possibility of iatrogenic spinal cord injury remains a serious complication. This is the first report of adverse reactions following microchip implantation in Japan, and it alerts the possibility of iatrogenic spinal cord injury secondary to inappropriate microchip implantation, where adequate training and extra caution is crucial especially in small light-weight animals.

Development of a Micro-PIXE Camera

We developed a system of μ-PIXE analysis at the division of Takasaki ion accelerator for advanced radiation application (TIARA) in Japan Atomic Energy Research Institute (JAERI), which consists of a microbeam apparatus, a multi-parameter data acquisition system and a personal computer. Elemental analysis in the region of 500 μ m × 500 μ m can be performed with a spatial resolution of < 0.3 μm and multi-elemental distributions are presented as images on a computer display even during measurement. We call this system a micro-PIXE camera.

APPLICATION OF MICRO-PIXE CAMERA TO ELEMENTAL ANALYSIS OF A SINGLE CELL

Since the cellular metabolism has not yet been fully elucidated, it is very useful to get the information of elemental distributions in a single cell. We applied a micro-PIXE camera to obtain a picture presented with density of an element in a cell. Our micro-PIXE camera is on the basis of PIXE analysis using micro ion beams with the spot size of less than 1 μ m and the samples can be analyzed in air, so the size and the state of samples are not limited. Here, we analyzed the spatial distributions of elements in a single cell of animal for a medical application. Bovine aortic endothelial cells(BAECs) were cultured in culture medium containing bromodeoxyuridine(BrdU) which is known to be used in the DNA synthesis. We could take the elemental maps of phosphorus, potassium and sulfur which present well a shape of cell and a position of nucleus in this cell. Moreover, we obtained the picture of Br , that is, BrdU. It was found that BrdU was locally concentrated in two or three regions in the nucleus.

Binding of calcium ions to cell membrane isolated from bullfrog skeletal muscle

The membrane fragments of bullfrog skeletal muscle fibers were isolated by a modification of the method of Kono and Colowick (1961). Radiocalcium ions were bound to these isolated membrane fragments, and the binding of calcium ions was impeded by both sodium and potassium ions. The extractable portion of the isolated membrane fragments with chloroform-methanol mixture bound calcium ions whereas no appreciable binding of calcium ions was observed with the extracted residue. The results suggested that the binding of calcium ions takes place on the lipid or lipoprotein of the so-called cytoplasmic membrane which plays an important role in regulating the membrane permeability and the membrane potential.