Yoshiaki Kadota

Skull base reconstruction in cases of intracranial teratoma extending into the extracranial structures

Recently experienced were two cases of postnatally diagnosed intracranial teratoma, one a mature teratoma and the other an immature teratoma, both extending into the extracranial structures. In each case, tumor resection was performed in which a barrier was created between the intracranial and extracranial spaces with a temporalis muscle flap. The technical aspect of skull base reconstruction is described, and previously reported cases of intracranial teratoma involving the skull base are reviewed.

MRI detection of ruptured malignant teratoma in the third ventricle

We describe a case in which CT and MRI showed evidence of intraventricular fat, which proved to have come from a ruptured malignant teratoma.

Ultrastructural evidence of peripheral neuropathy in spontaneous hyperglycemic Otsuka Long-Evans Tokushima Fatty rats: histopathological similarity to human diabetic neuropathy

The ultrastructure in the peripheral nerves of spontaneous hyperglycemic rats and of two cases of human diabetic neuropathy was compared using electron microscopy. Experimental animals were Otsuka Long-Evans Tokushima Fatty (OLETF) rats, bred to reveal spontaneous hyperglycemia and glucosuria after 20 weeks of age. The ultrastructural findings in the peripheral nerves of OLETF rats consisted of destructive changes of the myelin sheath, followed by axonal degeneration and basal laminal thickening of Schwann cells covering small-caliber axons. These alternations in the endoneurium were associated with the later onset of capillary vasculopathy, which revealed duplication of endothelial basal lamina and proliferation of microvilli at the luminal surface. It was characteristic that these histological alterations were apparently distinguished according to the duration of hyperglycemia between 10 and 30 weeks of age. The two human diabetic cases, who had suffered from non-insulin-dependent diabetes mellitus (NIDDM) for a considerable period, had undergone amputation of the leg following the onset of severe neuropathic ulcerative necrosis. Biopsied specimens from peripheral nerves revealed perineurial thickening, proliferation of endoneurial collagen tissue, loss of myelinated fibers, extension of Schwann cell processes with occasional “onion-bulb” formation, and endoneurial vascular basal laminal thickening. The results of these comparative histological studies suggested that the alterations occurring in peripheral nerve tissue of experimental diabetic OLETF rats may reflect the early pathological changes of human diabetic neuropathy.

Chapter 47: Neuro-hemal and neuro-glial specificities in the neural lobe of the pituitary gland

Publisher Summary Neurovascular specificity, with respect to the number of associations between regrowing neurosecretory axons (NSA) and fenestrated blood vessels (FBV) of the neural lobe may be possible because of the comparatively greater number of vessels and axons that regrow into grafted neural lobe. It has yet to be tested whether the pituicyte of the neural lobe is the cell responsible for the ingrowth of NSA and FBV. Agents such as peptide hormones or neurotransmitters, released into the interstitial compartment of the neural lobe, might regulate the shape and dimensions of the pituicyte. It is also likely that the pituicyte will turn out to be a significant target of these and other agents released within the neural lobe. It is proposed that the pituicyte, in addition to acting as a modulator of peptide hormone release from NSA, might have atrophic influence on the developing, mature and regenerating neurosecretory neuron and, perhaps, on fenestrated capillaries as well.