William F. Hickey

Positron emission tomography in patients with glioma. A predictor of prognosis.

Positron emission tomography (PET) studies have been performed using 18‐F‐fluorodeoxyglucose in 29 adult subjects with primary brain tumors. Seventy‐two percent of the patients were treated previously. The glucose metabolic state in the lesions was increased in 16 patients, and was normal or decreased in 13 patients. The hypermetabolic tumors tended to behave in a more malignant fashion. Patients with hypermetabolic tumors had a median survival of 7 months after PET scan, compared to 33 months for those with hypometabolic lesions. Among the high‐grade glioma patients, the PET results separated them into a good prognosis group (hypometabolic, with 78% 1‐year survival) and a poor prognosis group (hypermetabolic, with a 29% 1‐year survival after PET). These results suggest that glucose metabolic studies may provide an independent measure of the aggressiveness of a brain tumor, and may supplement pathologic grading.

Immunohistochemical and ultrastructural studies on the exenterated orbital tissues of a patient with graves' disease

The exenterated orbital contents obtained post mortem from a 47-year-old man who had an eight-month history of treated hyperthyroidism and a two-month history of visual complaints were examined histopathologically, immunohistochemically, and by electron microscopy. All of the extraocular muscles were massively enlarged, due to early diffuse endomysial fibrosis, mucopolysaccharide deposition, and a predominantly perivascular lymphocytic and plasmacytic infiltration. Histochemical stains revealed that the intramuscular mucopolysaccharides were weakly sulfated and polycarboxylated, establishing that they were products of fibroblastic activation rather than derived from mast cells. Subsarcolemmal deposits in the myofibers were shown by electron microscopy to be collections of glycogen rosettes with intermixed lipid deposits. These inclusions were interpreted as secondary phenomena due to abnormal muscle energetics from restrictions in contractility, and not as evidence of a primary degeneration of the extraocular muscle fibers themselves. The sarcomeric organization of the striated muscle cells was undisturbed, and therefore the pathologic changes occurred int he interstitial space of the endomysium. A monoclonal antibody specific for neurofilaments (antibody 4.3 F9) revealed, in comparison with normal controls, a preferential loss of large-type axons of the proximal segment of the orbital portion of the optic nerve as well as in the intracanalicular portion. The axonal loss was associated with a mildly increased number of astrocytes as demonstrated by an antibody against glial fibrillary acidic protein. The meninges of the optic nerve, the orbital fat, and the tendons of the extraocular muscles were uninflamed. The foregoing findings are compatible with a compressive optic neuropathy mediated by the massively swollen extraocular muscles impinging upon the optic nerve at the orbital apex.

Nimodipine attenuates both increase in cytosolic free calcium and histologic damage following focal cerebral ischemia and reperfusion in cats.

To clarify the mechanism of its effect on ischemic stroke, we investigated the effect of nimodipine, a dihydropyridine calcium antagonist, on changes in cytosolic free calcium, cortical blood flow, and histologic changes following focal cerebral ischemia and reperfusion in 14 cats. Using indo-1, a fluorescent intracellular Ca2+ indicator, we simultaneously measured changes in the Ca2+ signal ratio (400:506 nm), reduced nicotinamide adenine dinucleotide fluorescence (464 nm), and reflectance (340 nm) during an ultraviolet excitation (340 nm) directly from the cat cortex in vivo. In six cats treated with vehicle only, the calcium signal ratio increased from 5 minutes after middle cerebral artery occlusion to 30 minutes into reperfusion. The elevation of cytosolic free calcium was significantly attenuated by nimodipine, which was administered by intravenous infusion in eight cats starting 5 minutes after occlusion. Nimodipine had no effect on cortical blood flow during ischemia but induced a hyperperfused state following reperfusion. Nimodipine did not modify changes in the mitochondrial oxidation-reduction state. Nimodipine proved to have beneficial effects on recovery of the electroencephalogram following reperfusion as well as on the extent of focal histologic damage. Our results suggest that nimodipine, when administered during the early stage of focal ischemia, can favorably modify the outcome of stroke by reducing the Ca2+ entry during both the ischemic and reperfusion periods.

Expression of Ia molecules by astrocytes during acute experimental allergic encephalomyelitis in the Lewis rat

One question in the pathogenesis of experimental allergic encephalomyelitis (EAE) is whether antigen-presenting cells exist in the central nervous system which help induce the development of the disease. Since EAE is a delayed-type hypersensitivity condition, and since T cells require major histocompatibility complex (MHC)-restricted antigen presentation, it is presumed that if antigen presentation occurs in CNS tissue, the presenting cell should express surface Ia molecules. Using immunofluorescent double labeling, the possibility that astrocytes express surface Ia during EAE evolution in the Lewis rat was examined. Very rare Ia-positive astrocytes were found (less than 0.1% of the astrocytes), but only in the spinal cords of clinically ill animals. In addition, endothelial cell Ia positivity was noted prior to the onset of clinical disease. The immunological significance of such low numbers of astrocytes expressing Ia during EAE is uncertain.

A quantitative immunohistochemical comparison of actively versus adoptively induced experimental allergic encephalomyelitis in the Lewis rat

A quantitative immunohistochemical comparison of actively and adoptively induced experimental allergic encephalomyelitis (EAE) in the Lewis rat was performed. Since the methods of EAE induction of these two systems and the kinetics of disease appearance are different, while the histopathology, disease manifestations, duration, and severity are similar, this study sought to identify any differences which exist at the level of the target organ. The number of cells expressing the T helper (W3/25) or suppressor/cytotoxic (OX-8) phenotypes and the number of Ia-positive cells found in the spinal cord of animals given EAE by one of the two methods were compared at two time points at which maximal similarities should exist. The results show that during acute adoptively induced EAE the inflammatory infiltrate contains a larger number of T helper (TH) cells per unit area than in acute active EAE. With the resolution of clinical signs of EAE, the disappearance of cells from the spinal cord is more rapid in adoptive EAE. In contrast, the inflammatory infiltrate and Ia-positive parenchymal cells persist in active EAE following recovery. These results suggest that actively and adoptively induced EAE may differ with respect to the effector mechanisms and/or the mechanisms of recovery at the level of the target organ.

Suppressor T-lymphocytes in the spinal cord of Lewis rats recovered from acute experimental allergic encephalomyelitis

The quantity and distribution of T-lymphocyte phenotypes in the spinal cord of Lewis rats which have recovered from acute encephalomyelitis (EAE) were studied. Lymphoid cells were detected in the spinal cords of all the recovered, asymptomatic rats for periods up to 4 months after recovery. The major difference between the T-lymphocyte populations found in acute EAE compared to the asymptomatic chronic condition was the increase of OX-8 (suppressor) T cells. Thus, the cellular infiltration of the CNS in EAE in the rat appears to be persistent after clinical recovery. Furthermore, the association between OX-8 cells in the spinal cord and the symptom-free stage of the disorder suggests that these suppressor cells exert an effect at the level of the target organ.

Effect of the ganglioside GM1 on neurologic function, electroencephalogram amplitude, and histology in chronic middle cerebral artery occlusion in cats.

The effect of the ganglioside GM1 on amplitude of the electroencephalogram, neurologic function, and histology has been studied in chronic middle cerebral artery occlusion in cats. Ischemia was produced by a 2-hour occlusion of the left middle cerebral artery and was followed by a 7-day observation period. GM1 was intravenously administered 30 minutes after occlusion and daily during the observation period. Using the reduction in the electroencephalogram amplitude to measure stroke severity, three cats with mild, three cats with moderate, and three cats with severe stroke were treated with 5 mg/kg GM1. Nine cats, three in each group, were treated with 30 mg/kg GM1, while nine cats, three in each group, received middle cerebral artery occlusion but no treatment. In all cats there was a precipitous fall in mean electroencephalogram amplitude during occlusion, followed by a secondary fall during the observation period. Treated cats showed better recovery of electroencephalogram amplitude during the first 4 hours of reperfusion and a smaller secondary fall than untreated cats. Treated cats, especially those treated with 5 mg/kg GM1, showed significant recovery of neurologic deficits compared with untreated cats. Histologic damage was less in treated cats than in untreated cats. Some cats treated with 30 mg/kg GM1 exhibited convulsions, whereas no untreated cat showed any seizure activity. Our findings suggest that gangliosides may improve the recovery of both neurologic deficits and morphologic damage in the central nervous system. These positive effects might be tentatively explained by stimulation of enzymatic activities such as Na+, K+-ATPase and adenyl cyclase.

Actively-Induced Experimental Allergic Orchitis (EAO) in Lewis/Ncr Rats: Sequential Histo- and Immunopathologic Analysis

Active experimental allergic orchitis (EAO) was induced in Lewis/NCr rats by immunization with homologous rat testicular homogenate. Groups of animals were studied sequentially at five day intervals for histopathologic signs of disease. Inflammatory lesions were first observed in the ductus efferentes as early as 5 days following immunization. Immunohistochemical analysis of the testes, rete testis, ductus efferentes and caput, corpus and cauda epididymis of immunized rats on day five revealed that only the ductus efferentes exhibited a significant increase in the number of interstitial cells expressing Ia antigens (MRC OX-6) as well as CD4 (W3/25) positive helper/inducer T lymphocytes, CD8 (MRC OX-8) positive cytotoxic T lymphocytes and/or natural killer cells and macrophages (MRC OX-42). Increased staining for Ia antigens was also associated with both the vascular and ductal epithelial cells whereas cells within the lumen of the ducts were consistently negative for Ia antigen expression. In contrast, there was no detectable increase in the level of expression of rat MHC class I antigens (MRC OX-18) by any of the cells of the ductus efferentes. Similarly, there was no increase in the number of MAR 18.5 and/or MRC OX-12 positive B lymphocytes. By day 15, autoimmune epididymitis was observed in the cauda and corpus epididymis with the caput becoming involved by day 20. In the testes, the first histopathologic changes observed were scattered inflammatory infiltrates on day 15 and scattered foci of aspermatogenesis on day 20. Inflammatory lesions were first seen in the rete testis and the seminiferous tubules on day 25-30 with maximal involvement occurring on day 35-40. Early inflammatory lesions in the seminiferous tubules were characterized by peritubular and/or interstitial mixed cellular infiltrates. Later lesions included granuloma formation and necrosis. Autoimmune vasitis was not seen in any of the animals studied. Control rats immunized with rat liver homogenate plus adjuvants or adjuvants alone did not exhibit any of the histopathologic lesions described above. The observed results, when compared to those of previous studies examining the sequential histo- and immunopathology of active EAO in the guinea pig and mouse, support the concept that: 1) significant species specificity may exist with regard to regional differences in susceptibility to autoimmune attack within the male reproductive tract and 2) that such differences correlate with early maximal expression of Ia by cells within the male reproductive tract.

Nerve growth factor induced changes in the Golgi apparatus of PC-12 rat pheochromocytoma cells as studied by ligand endocytosis, cytochemical and morphometric methods

SummaryCells of the PC-12 rat pheochromocytoma cell line respond to nerve growth factor (NGF) by sprouting neurites and biochemically differentiating into sympathetic ganglion-like cells. NGF-stimulated (‘differentiated’) and unstimulated (‘undifferentiated’) cells were studied by cytochemical techniques for the localization of the enzymes acid phosphatase (ACPase) and thiamine pyrophosphatase (TPPase), and by a morphometric analysis of the distribution of endocytosed wheat-germ agglutinin labelled with horseradish peroxidase (WGA-HRP). Both cytochemical stains showed the enzymes to be distributed in lysosomes and certain cisternae of the Golgi apparatus in both NGF stimulated and unstimulated cells. ACPase was not confined to GERL (Golgi-endoplasmic reticulum-lysosome) as in certain other cells. The morphometric studies demonstrated that the reaction product of the internalized WGA-HRP occupied 4.7% of the cytoplasmic area in unstimulated cells and 4.5% in NGF-stimulated ones. Despite this similarity, the distribution of the WGA-HRP among the studied intracellular compartments in these two cell groups varied. In the NGF-stimulated cells 3.3% of the WGA-HRP reaction product was found in the innermost Golgi cisterna(e) while in unstimulated cells only 0.3% was seen in this compartment. Similarly, 4.3% of the WGA-HRP stain was found in small vesicles at the ‘trans’ aspect of the Golgi apparatus in stimulated cells, when only 0.3% of the stain occupied this compartment in ‘undifferentiated’ cells. The morphometric analysis also revealed that when the PC-12 cells were stimulated with NGF, the Golgi apparatus increased in area by approximately 70%. These findings are consistent with the hypothesis that NGF induced differentiation of PC-12 cells is coupled with enhanced endocytosis of WGA and probably of its ‘receptor’ to the innermost Golgi cisterna(e) and the closely associated vesicles.

Experimental allergic orchitis in mice: IV. Preliminary characterization of the major murine testis specific aspermatogenic autoantigen(s).

Active experimental allergic orchitis (EAO), characterized by inflammation of the testes (autoimmune orchitis), aspermatogenesis, epididymitis and vasitis was induced in mice using a panel of tissue antigens as immunogens. Immunization with allogeneic murine tissue homogenates emulsified in complete Freunds adjuvant (CFA) accompanied by the injection of pertussigen revealed that only adult murine testicular and epididymal homogenates are capable of eliciting murine EAO. All other tissue antigens studied including prepubertal mouse and epididymal homogenates failed to elicit significant disease. Immunization with xenogeneic testicular antigens also failed to elicit significant disease indicating that the major murine aspermatogenic autoantigen(s) is also highly species specific. Sensitization with allogeneic mouse testicular homogenates (MTH) from different disease resistant strains was for the most part no less potent in inducing significant disease than was immunization with mouse testicular homogenates from disease susceptible strains. However, testicular homogenates from NZB/B1NJUnm and MRL/MpJ-/+Unm mice were significantly less potent at inducing autoimmune epididymitis as compared to other strains, indicating possible interstrain differences in the immunogenicity of the aspermatogenic autoantigen(s) relevant to eliciting epididymitis. Attempts at solubilization and purification of the major murine aspermatogenic autoantigen(s) utilizing techniques employed for the purification of aspermatogenic autoantigens such as AP3 from guinea pig (GP) testes were unsuccessful. Additional extraction procedures resulted in solubilization of the relevant autoantigen(s) only after reduction in the presence of 6 M guanidine hydrochloride. These data suggest that: (1) there may be a much more limited number of aspermatogenic autoantigens in murine testes as compared to GP testes; (2) the disease inducing determinant(s) may be expressed as either a sequential antigenic determinant(s) or as an antigenic determinant(s) in the carbohydrate portion of a glycoprotein or glycopeptide; and (3) the disease inducing autoantigen(s) may be present in situ in a highly insoluble form requiring active processing within the target organ in order to generate soluble antigen capable of being seen by immune reactants.