Donald Duncan

A DISTINCTIVE LAMINATED CYTOPLASMIC BODY IN THE LATERAL GENICULATE BODY NEURONS OF THE CAT.

A cytoplasmic body exhibiting precise order is described in this report. Such bodies were found in many lateral geniculate body neurons from four unselected and apparently healthy cats. So far they have not been seen in any other neurons, nor has any previous description of them been located. These bodies are of the same general size as the nucleoli of the lateral geniculate body neurons, and they stain as nucleoli do with basic dyes. Each body consists of precisely spaced layers of minute dense-walled tubules arrayed in parallel but curving arrays. The tubules are remarkably uniform in size with a diameter of about 250 A. Each layer of tubules is separated by an interval of 750 A occupied by material of moderate density that is neither amorphous nor of clearly defined structure. No suggestion of source or functional significance is offered in this report.

Multilaminated bodies and other unusual configurations of endoplasmic reticulum in the cerebellum of the cat. An electron microscopic study.

Multilaminated bodies which are smaller but structurally identical to those previously reported ( 11 ) in neurons of the lateral geniculate body of cats were found in stellate neurons of the cerebellar cortex in the same species. In addition to reporting this finding, attention is called to other unusual formations apparently derived from endoplasmic reticulum. These include clusters of tubules within dendrites and axoplasm and laminar arrays of closely approximated endoplasmic sacs. The last-mentioned arrangement is probably a result of fixation procedures, but the other objects are believed to be present in the living cytoplasm although agonal and early postmortem alterations have not been excluded.

Mitochondrial alterations in cultures of the central nervous system as observed with the electron microscope

Summary and conclusionElectron microscope observations on sections prepared from cultures of the cerebellum and the region of the mesencephalic nucleus of the trigeminal nerve of young kittens reveal a profusion of complex bodies that can be identified as lipid inclusions. These inclusions are not limited to any type of cell within the culture and can be found in newly formed myelinated fibers as well as cells and parts of cells that represent original explant material. Since the lipid droplets, except the very largest, have the sizes and distribution of mitochondria, and because bodies with intermediate features are numerous, the lipid droplets are considered to be transformed mitochondria.

Electron and Fluorescence Microscopy of Mouse Hepatitis Virus.

Summary Livers of mice infected with mouse hepatitis virus (MHV 1) were examined by conventional staining procedures and by electron and fluorescence microscopy using acridine orange fluorochrome and fluorescein-tagged antibody. Preparations stained with acridine orange showed abnormal accumulations of RNA-staining material in cytoplasm of hepatic cells. Inclusion bodies of similar size, shape, and location were stained selectively with fluorescein-tagged antibody. Observations by electron microscopy showed virus particles in cytoplasm which measured 90 ± 20 mμ in diameter. The authors are indebted to Dr. R. H. Rigdon and his staff for invaluable technical assistance.

A special type of filament in the Purkinje cells of the Syrian hamster

SummaryThe Purkinje cells of the Syrian hamster cerebellum contain dense filaments 75 Å in diameter and of relatively great hut undetermined length. These filaments occur in closely packed bundles that curve and twist through the perikaryal cytoplasm. They are always closely associated with mitochondria, never with the Golgi apparatus. Absence of previous descriptions of similar neuronal filaments indicates that they may be a unique feature in the hamster cerebellum.

Some Results of Substituting Other Nerves for the Phrenic

Summary and Conclusions The spinal accessory, the long thoracic and facial nerves were substituted for one phrenic nerve in cats and rats. All of these nerves will supply motor fibers to the diaphragm sufficient for it to serve as the only respiratory muscle. Lack of proper central connections prevents spontaneous use of this power in the animals tested.

Some Effects of Anesthetic Mixtures Dissolved in Oil on Motor Nerves in the Gat

Summary Mixtures of local anesthetic substances dissolved in oil were injected into the subcutaneous tissues of the face in cats. Paralysis of the orbicularis oculi muscle was invariably obtained with solutions containing either procaine base or nupercaine hydrochloride. The paralysis lasted from several hours as a minimum to a maximum of 21 days. Histological examination of the tissues 10-31 days after injection revealed degeneration of facial nerve fibers in every case. The amount of degeneration varied from a few scattered fibers to complete in some branches. In general the amount of degeneration corresponded to the duration of the paralysis. Injections of the oil vehicle alone caused no paralysis and no degeneration.

Survival of dogs with bilateral phrenectomy and extensive transection of intercostal nerves.

Summary Seven dogs were kept in good health and without respiratory distress for periods varying between 9 and 67 days after bilateral phrenectomy. All of the animals were eventually sacrificed, none died as a result of paralyzing the diaphragm. Electrical stimulation and microscopic examination proved that the phrenectomies were complete in all cases. It was established that following paralysis of the diaphragm at least half of the intercostal nerves, either upper or lower, may be sectioned without loss of the animal. The conclusion drawn is that reports or statements to the effect that the diaphragm is essential for life in otherwise intact grown dogs are erroneous.