Biomedical subjects
Publications and source records attributed to S I Zacks.
We report a unique case of amyloidosis presenting as a localized soft tissue mass in the shaft of the penis unassociated with systemic amyloidosis, trauma, penile ulcers, syphilis or other venereal diseases. The patient presented with a penile mass and intermittent hematuria. Biopsy revealed homogeneous deposits of amorphous eosinophilic material, and histochemistry and electron microscopy demonstrated the classical features of amyloid.
A combined immunohistochemical and ultrastructural study of 20 cerebellar medulloblastomas has demonstrated features of early neuronal differentiation. The differentiation features are primarily encountered in the Homer Wright rosettes and in the reticulin-free "pale islands," or "follicles," of the desmoplastic variant. They consist of parallel arrays of aggregated neurite-like processes containing longitudinally oriented microtubules (immunoreactive for polyvalent antisera to tubulin and gamma-enolase, but nonreactive for a monoclonal antibody to the 150/200 kD subunits of neurofilament protein) and junctional adhesion plaques. We consider the inherent property of self-aggregation of the neurite-like processes with adhesion plaques a significant mechanism in the formation of Homer Wright rosettes. Further differentiation and elongation of these cell processes may lead to the formation of "pale islands" in the desmoplastic medulloblastoma. A meshwork of astroglial cells, coexpressing glial fibrillary acidic protein and S-100 protein immunoreactivity, forms an integral part of the "pale island." The histogenetic significance of these astrocytes and their relationship to tumor cells expressing early neuronal differentiation remains to be defined.
The temporal lobe agenesis syndrome is a rare congenital abnormality. In previous case reports, this syndrome has been described in association with arachnoid cysts or abnormal collections of CSF. An autopsy performed in the case of our 25-year-old patient revealed agenesis of frontal and temporal lobes without an anatomic cyst. During life the patient had no neurologic abnormalities that could be related to the lesion.
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Rapid regeneration of mouse anterior tibial muscle occurs when minced muscle is explanted into the leg of a recipient previously prepared by excision of the corresponding anterior tibial muscle. This technique was used to study regeneration of muscle from mice with a delayed, recessive myopathy, motor endplate disease (MED). There was rapid regeneration of the explanted muscle and functional restoration after 15 weeks without signs of MED disease or evidence of the myofiber degeneration which normally occurs after 14 days in homozygous animals. Therefore, MED disease is not intrinsic in the affected muscles but appears to be dependent on the general humoral or possibly neural, environment present in mice with MED disease.
A fatal, rapidly developing progressive muscle disease of delayed onset in mice is produced by the effects of an autosomal recessive gene (MED). We recognize two stages of this disease. The earlier stage, observed between the 11th and 14th postnatal day, is characterized by structurally normal small myofibers, cessation of increase in body weight, and increasing muscular weakness, particularly of the hind limbs. The second stage is characterized by a spheromembranous degeneration of myofibers and almost complete cessation of voluntary movement. Previous studies have revealed neither anatomic abnormalities in neuromuscular junctions nor major changes in oxidative metabolism or electrolyte concentrations in striated myofibers in the early stages of the disease. In this paper we report investigations designed to determine whether the failure of growth of striated muscle in the first stage is due to a defect in muscle protein synthesis or, as has been found in muscular dystrophies, is due to an increased rate of degradation of muscle. We conclude that MED animals demonstrate a different kind of defect than that occurring in dystrophic mice. In MED mice, the failure of growth is primarily due to a diminished rate of protein synthesis.
Although it has long been known that both large and small blood vessels are abnormal in the tissues of diabetic patients, recent work has emphasized the widening of capillary basement membranes in diabetic tissues. Current views of the nature of this lesion and its relationship to diabetes are discussed and diabetic muscle and nerve lesions are emphasized. Other metabolic diseases with significant muscle pathology are types II, III and VII glycogen storage diseases. Myopathy with abnormal mitochondria is reviewed.
Diagnosis of neuromuscular disease by the study of motor endplate structure in the light and electron microscopes is probably one of the most specialized examinations in the field of neuropathology. The classical means of staining endplates using gold, silver or methylene blue are described as well as more modern techniques suitable for light microscopy. Specific abnormalities in patterns of terminal innervation after methylene blue staining are noted. Techniques for localizing endplates suitable for electron microscopic study are given and some of the typical changes that occur in endplate structure in some neuromuscular diseases are indicated.