Management of thyroid carcinoma with radioactive 131I.

PURPOSE: To evaluate the role of radioactive 131I in the management of patients with well differentiated carcinoma of the thyroid. METHODS AND MATERIALS: Between 1965 and 1995, a total of 117 patients with well-differentiated carcinoma of the thyroid underwent either lobectomy or thyroidectomy followed by 100-150 mCi of 131I. RESULTS: With a median follow-up of 8 years, only four patients (3%) developed a recurrence of their disease. The 5-year actuarial survival was 97% with a 10-year survival of 91%. There were no severe side effects noted after 131I therapy. CONCLUSIONS: Radioactive 131I is a safe and effective procedure for the majority of patients with well-differentiated thyroid carcinoma. We currently recommend that all patients undergo a subtotal or total thyroidectomy followed by 131I thyroid scanning approximately 4 weeks after surgery. If the thyroid scan shows no residual uptake and all disease is confined to the thyroid, we recommend following patients with annual thyroid scans and serum thyroglobulin levels. If there is any residual uptake detected in the neck or if the tumor extends beyond the thyroid, we recommend routine thyroid ablation of 100-150 mCi of radioactive 131I.

Axonal growth into tubes implanted within lesions in the spinal cords of adult rats.

Cultured Schwann cells were implanted into the thoracic spinal cords o f adult rats inside thin tubes made of polycarbonate film coated with poly-L-lysine. Additional control tubes were implanted which did not contain cultured Schwann cells. Some of the control tubes were coated with poly-L-lysine and others were not. One week to 2 months later the animals were perfused with fixatives and the tubes were prepared for light or electron microscopy. Immunocytochemical studies of the Schwann cell tubes reveal that they contain axons. Most of these axons are grouped in fascicles that run longitudinally through the tubes. The distribution of these axons matches precisely the distribution of basal lamina within the tubes as displayed by immunolabeling with an antibody to laminin. Surprisingly, the same patterns of labeling are seen in the control tubes, although they contain fewer axons. Control tubes lacking poly-L-lysine contain the fewest. Electron microscopy verifies that the tubes, including control tubes, contain Schwann cells and axons of different diameters. Furthermore, the Schwann cells ensheathe and myelinate the axons. These results strengthen the hypothesis that Schwann cells can support axonal growth in the spinal cords of adult animals. They also demonstrate that these Schwann cells can be implanted or they can be derived from the host animal. This finding raises the possibility that therapies could be devised for bridging spinal cord lesions that are based on maximizing migration of endogenous host cells into the sites of lesions.

Implants of cultured Schwann cells support axonal growth in the central nervous system of adult rats.

Growing axons require an appropriate substrate on which to elongate. In the peripheral nervous system Schwann cells provide this substrate, and in the developing central nervous system (CNS) astrocytes are involved. In the adult CNS damaged axons do not normally regenerate but they can grow through peripheral nerve grafts. Also, they can grow along sheets of implanted Schwann cells or astrocytes. This study examines the ability of dissociated suspensions of Schwann cells and astrocytes to support axonal growth when implanted into the brains of adult rats. Schwann cells and astrocytes are cultured from near-term rat fetuses or newborn pups. They are transferred to polycarbonate tubes, and one end of each tube is inserted into the dorsal thalamus. The other end is secured extracranially. After 4 weeks to 6 months, the tubes are filled with tissue and are well vascularized. Evidence that Schwann cells support axonal growth comes from retrograde labeling studies in which horseradish peroxidase is applied to the extracranial ends of the tubes. In addition, immunolabeling reveals axon-like fibers inside the tubes using three neuron-specific antibodies. Finally, electron microscopy shows that these tubes contain small peripheral nerve-like structures consisting of myelinated and unmyelinated axons and a perineurial wrapping. Tubes filled with astrocytes contain less tissue than Schwann cell tubes and cells in the brain could not be retrogradely labeled by applying HRP to the extracranial ends. However, immunocytochemical studies reveal axon-like fibers extending for several millimeters into these tubes although few, if any, reach the external end.

Fourth ventricular entrapment caused by rostrocaudal herniation following shunt malfunction.

The subacute development of isolated fourth ventricle (IFV) is a recognized complication following shunting of the lateral ventricles for congenital and acquired hydrocephalus. We present an unusual case of acute IFV in a clinical setting which has not previously been described. Subsequent to rostrocaudal herniation caused by an obstructed frontally placed ventricular catheter, IFV developed in our patient 24 h following shunt revision, necessitating placement of an additional fourth ventricle shunt system. No signs of intraventricular hemorrhage or cerebrospinal fluid (CSF) infection were detected at the time of shunt revision and there was no documentation of similar events in the perinatal history. Dependent upon the actual underlying etiology of this child's hydrocephalus, we hypothesize that two mechanisms may have accounted for this unusual and precipitous development of IFV. Following rostrocaudal herniation and caudal shift of the brainstem, progressive edema in the pons developed. If communicating hydrocephalus was the primary etiology, then midbrain edema occluded the aqueduct of Sylvius, preventing retrograde flow of CSF to the shunt. A distinctly different mechanism for acute IFV must be invoked if aqueductal stenosis was the preexisting cause for congenital hydrocephalus. Following herniation, brainstem displacement and edema resulted in obliteration of the lateral pontine and ambient cisterns, preventing the normal rostral migration of CSF around and over the mesencephalon. Cerebellar tonsillar herniation with impaction of the tonsils into the foramen magnum may have also contributed to obstruction of fourth ventricular outflow in both settings. This unusual case of acute onset IFV is presented in detail. The underlying etiologies and clinical settings in which IFV may develop is reviewed as well.(ABSTRACT TRUNCATED AT 250 WORDS)

New method of transplanting purified glial cells into the brain.

This paper describes a new transplantation method for testing the ability of purified populations of glial cells to support axonal growth in the brains of adult animals. Thin tubes, rolled from porous polycarbonate film, are coated with poly-L-lysine and filled with cultured Schwann cells. Schwann cell-filled tubes or control tubes (poly-L-lysine coated only) are then implanted into the brains of adult rats so that one end of the tube is in the thalamus and the other extends extracranially. After survival times of 4-16 weeks horseradish peroxidase (HRP) is applied to the extracranial end of the tube. One or two days later the animal is perfused and the brain is sectioned and processed histochemically. Results show that tubes containing Schwann cells are densely filled with tissue and are well vascularized. Further, neurons in the central nervous system are retrogradely labeled with HRP and most labeled cells are concentrated in regions of the diencephalon near the end of the tube. Control tubes contain very little tissue and show no evidence that they support axonal growth. These results are consistent with the hypothesis that Schwann cells can support axonal growth in the brains of adult rats.