“Dark” (compacted) neurons may not die through the necrotic pathway

Dark neurons were produced in the cortex of the rat brain by hypoglycemic convulsions. In the somatodendritic domain of each affected neuron, the ultrastructural elements, except for disturbed mitochondria, were remarkably preserved during the acute stage, but the distances between them were reduced dramatically (ultrastructural compaction). Following a 1-min convulsion period, only a few neurons were involved and their environment appeared undamaged. In contrast, 1-h convulsions affected many neurons and caused swelling of astrocytic processes and neuronal dendrites (excitotoxic neuropil). A proportion of dark neurons recovered the normal structure in 2 days. The non-recovering dark neurons were removed from the brain cortex through two entirely different pathways. In the case of 1-h convulsions, their organelles swelled, then disintegrated and finally dispersed into the neuropil through large gaps in the plasma membrane (necrotic-like removal). Following a 1-min convulsion period, the non-recovering dark neurons fell apart into membrane-bound fragments that retained the compacted interior even after being engulfed by astrocytes or microglial cells (apoptotic-like removal). Consequently, in contrast to what is generally accepted, the dark neurons produced by 1-min hypoglycemic convulsions do not die as a consequence of necrosis. As regards the case of 1-h convulsions, it is assumed that a necrotic-like removal process is imposed, by an excitotoxic environment, on dark neurons that previously died through a non-necrotic pathway. Apoptotic neurons were produced in the hippocampal dentate gyrus by intraventricularly administered colchicine. After the biochemical processes had been completed and the chromatin condensation in the nucleus had reached an advanced phase, the ultrastructural elements in the somatodendritic cytoplasm of the affected cells became compacted. If present in an apparently undamaged environment such apoptotic neurons were removed from the dentate gyrus through the apoptotic sequence of morphological changes, whereas those present in an impaired environment were removed through a necrotic-like sequence of morphological changes. This suggests that the removal pathway may depend on the environment and not on the death pathway, as also assumed in the case of the dark neurons produced by hypoglycemic convulsions.     

Intravenous and intramuscular pharmacokinetics of recombinant leukocyte a interferon

Summary Interferon is currently being evaluated for the treatment of disseminated cancer and viral diseases. Alpha interferons have shown to be effective in the treatment of a number of malignancies. Recombinant leukocyte A interferon (rIFN-A) is an alpha interferon produced by recombinant DNA techniques. A kinetic evaluation of rIFN-A following intravenous and intramuscular administration has not been adequately defined. The present study was designed to evaluate the kinetics of rIFN-A following intravenous and intramuscular administration of 3, 9 or 18×10⁶ units to patients with disseminated cancer.A preliminary report of this study was presented at the meeting of the American Society for Clinical Pharmacology and Therapeutics in San Diego, March 1983 (1).     

Surgical remodeling of the silhouette by aspiration lipolysis or selective lipectomy

The author, a pioneer in originating the technique of suction lipectomy, discusses in detail the pathophysiology of the fat cell and fat metabolism. In addition, he describes the surgical means by which, since 1977, he has popularized this innovative new approach to the treatment of unsightly fat deposits in many sites in the body, including the thighs, buttocks, abdomen, hips, arms, ankles, breasts, and submental regions.     

Post-traumatic epidural hematoma in two patients with long-standing “arrested” hydrocephalus

The occurrence of a post-traumatic epidural hematoma in two patients with long-standing arrested hydrocephalus is reported. There was a relatively long interval between the head injury and the onset of symptoms. The large hematoma was accommodated by the decrease in size of the markedly dilated ventricles. This report stresses the possibility of the presence of an epidural hematoma in the management of head injury in patients with long-standing arrested hydrocephalus.     

Axonal and myelin lesions inβ-mannosidosis: Ultrastructural characteristics

Summary Ultrastructural changes in central nervous system (CNS) white matter of three goats affected with-mannosidosis were analyzed to further define characteristics and pathogenesis of axonal and myelin abnormalities. The variations in myelin association and contents of axonal spheroids were delineated. The occurrence of spheroids in a 96/150-day fetus documented the early development of these axonal lesions. In regions of severe myelin deficits, the presence of apparently normal axons and a reduction in the number of oligodendrocytes were confirmed. Many remaining cells in myelin-deficient regions were characterized by dark, vacuolated cytoplasm. The occurrence of internodes with myelin sheaths adjacent to internodes without myelin sheaths suggested that an axonal defect is not primarily responsible for the absence of myelin sheaths. A mild myelin deficit in the spinal cord was indicated by the presence of unmyelinated axons. Except for occasional mild cytoplasmic vacuolation, the spinal cord glial cells appeared relatively normal. The findings presented here are consistent with the hypothesis that an oligodendrocyte defect, expressed by regional differences, is a major factor in the pathogenesis of myelin deficiency in-mannosidosis.Supported by NIH grant NS-16886 to MZJ and BRSG funds from the College of Osteopathic Medicine, Michigan State University, to KLL     

Reversible “locked-in” syndromes

Two young patients are described who made good recoveries from a locked-in syndrome presumed to be due to ventral pontine ischemia. The first patient recovered completely from quadriplegia and mutism. In the second patient the only permanent sequellae were slight dysarthria and mild spasticity. Since patients may recover nearly completely from a locked-in syndrome, aggressive supportive therapy seems justified during the initial weeks or months.     

Potentiation of central effects of L-dopa by an inhibitor of catechol-O-methyltransferase

Summary The effects of a COMT-inhibitor, U-0521, and a MAO-B-inhibitor, l-deprenyl, on L-dopa-induced circling behaviour were compared in 6-OHDA-lesioned rats. The actions of U-0521 and l-deprenyl on the anticataleptic effect of L-dopa were also studied. Both U-0521 and l-deprenyl were found to potentiate L-dopa-induced circling behaviour and anticataleptic effect of L-dopa. In both test systems the L-dopa potentiation of l-deprenyl was longer-lasting than that caused by U-0521. Thus inhibition of COMT, like inhibition of MAO, is able to enhance the central effects of L-dopa. This principle might be beneficial in the treatment of Parkinson's disease especially if COMT-inhibitors with greater performance can be developed.     

[3H] UK-14,304, a new agonist ligand of α2-adrenoceptors: a comparative study with human and rat tissue

Summary [³H] UK-14,304 was used to investigate ₂-adrenoceptors in rat brain and human platelets. Receptor pharmacology revealed that the ligand binds with high affinity to ₂-adrenoceptors. Psychoactive substances like neuroleptics, antidepressants, and-carbolines displace [³H] UK-14,304 from its binding sites in the lower micromolar range. A Hill number around 2 for most neuroleptics suggests a positive cooperativity with the ₂-adrenoceptors.Comparative studies with [³H] UK-14,304 and [³H] clonidine utilizing platelet membranes from human volunteers demonstrated that the former ligand is more suitable to investigate possible changes of ₂-adrenoceptors; [³H] UK-14,304 labels more receptors with a lower standard deviation, whereby the volume of the blood sample amounted to 35 ml instead of 50 ml required for [³H] clonidine as ligand. No sex differences of binding constants were detected, however an inverse correlation of maximum number of binding sites and affinity was found for female subjects with both ligands.No age-dependent changes of B_max and K_D-values were observed in the range of 24 to 59 years.     

High resolution real-time B-mode echotomography in the diagnosis of extracranial carotid lesions. Comparison with traditional angiography

Summary Tumour growth essentially requires fibrin formation and fibrinopeptide A (FPA) is liberated into the circulation on fibrin formation. In the present study, a possible elevation of serum FPA level was examined in patients with metastatic brain tumour. A significant elevation of serum FPA level was shown in all 6 patients with metastatic brain tumour, when blood was drawn from the internal jugular vein. It was extremely high in 2 patients with rapidly growing tumour. However, such a significant elevation was not shown in 3 cancer patients without brain metastasis or in 1 patient with a huge meningioma. This suggests the possibility that the presence of metastatic brain tumour could be detected by measuring FPA in blood drawn form the internal jugular vein. This also suggests the tendency that elevation of serum FPA is higher in patients with more rapidly growing tumour.Infusion of urokinase into the internal carotid artery resulted in an elevation of serum fibrinopeptide B (1)15–42 (FPB) in 5 patients with metastatic brain tumour, when blood was drawn from the internal jugular vein. This suggests that urokinase could induce fibrinolysis in the tumour tissue, though this remains in conclusive because of the lack of complete controls.