Expression of bcl-2 in reactive and neoplastic astrocytes: lack of correlation with presence or degree of malignancy

The bcl-2 protooncogene encodes a 26-kD protein that extends cell survival by blocking apoptosis. This protein has been found to be overexpressed in neoplastic neural cell lines, although its expression in reactive and neoplastic astrocytes in vivo has not been well characterized. The authors hypothesized that bcl-2 oncoprotein expression in gliomas might be positively correlated with the tumor's degree of malignancy. Sixty-three gliomas of various subtypes and histological grades were immunostained by bcl-2 protein and the percentage of positive cells was quantitatively assessed. All tumors contained neoplastic cells that were immunoreactive for the bcl-2 protein (range of cell positivity 1%-53%). It was found that bcl-2 expression did not vary significantly as a function of tumor subtype or grade (p < 0.1, one-way analysis of variance (ANOVA) on ranks) as compared to the cell proliferation marker Ki-67 (MIB-1) in which a very significant correlation with tumor grade was noted (p < 0.0000001, one-way ANOVA on ranks). In fact, the highest percentage of bcl-2 immunoreactive cells was noted in low-grade gliomas, that is, in juvenile pilocytic astrocytomas and oligoastrocytomas. The specificity of bcl-2 overexpression was also assessed in 10 nonneoplastic lesions associated with prominent reactive astrocytosis. In nine of these cases (90%), bcl-2-positive reactive astrocytes were observed, often in large numbers, whereas relatively few Ki-67 immunoreactive cells were noted. The authors conclude that bcl-2 oncoprotein expression as assessed immunohistochemically does not correlate with glial tumor type or grade and its overexpression is not confined only to neoplastic conditions. Instead, the finding of robust bcl-2 expression in low-grade glial tumors and in reactive astrocytes warrants the inference that resistance to apoptosis is a nonspecific finding in astrocytes associated with both reactive and neoplastic conditions.

Low-grade gliomas

Supratentorial low-grade gliomas comprise a group of primary central nervous system neoplasms with characteristics of neuroglial cells (i.e., astrocytes and oligodendrocytes) and relatively low anaplastic potential, although through time they tend to behave more aggressively. Immediate surgical intervention and subsequent radiation therapy are advocated by some workers; at present, however, it remains unclear whether early intervention prolongs survival or changes the natural history of the disease, especially in those patients who present with a seizure and a normal interictal examination.

The preponderance of posterior circulatory events is independent of the route of cardiac catheterization

BACKGROUND AND PURPOSE

Central nervous system complications of cardiac catheterization are most often attributed to embolic events that occur at the time of catheter manipulation. Nevertheless, the reason that over 50% of these events are localized to the posterior circulation remains unexplained. One potential explanation offered for this preponderance is the use of the brachial artery approach. In this report, we examined the relation between the route of catheterization and central nervous system complications.

SUMMARY OF REPORT

We retrospectively analyzed all central nervous system complications that occurred after cardiac catheterization through a femoral route at our institution over a 3 1/2-year period. Thirteen patients were identified as having central nervous system complications. Using defined criteria, posterior circulatory events still accounted for at least 54% of central nervous system complications.

CONCLUSIONS

The preponderance of posterior circulatory events is apparently independent of the route of catheterization. Furthermore, given the array of neurological symptoms and their often complete resolution, we feel it is unlikely that embolism is the sole pathophysiological mechanism involved in these events.

Suspected low-grade glioma: is deferring treatment safe?

Deferring therapeutic intervention may worsen outcome in patients with low-grade glioma. To address this issue, we searched our records and located 26 patients who presented with a transient event (most often seizures), who had radiographic evidence strongly suggestive of a low-grade primary supratentorial neoplasm, and for whom all therapy (except anticonvulsants) was withheld until deemed necessary (WAIT Group). For comparison, 20 patients who presented similarly, but for whom immediate intervention was elected, served as a comparison group (NOWAIT Group). Fifteen patients in the WAIT Group required eventual surgery or radiation therapy at intervals ranging from 4 to 123 months (median, 29 months) between radiographic diagnosis and therapeutic intervention; reasons for such intervention included increasing tumor size, uncontrollable seizures, or malignant transformation of tumor. At surgery, there was an increased number of anaplastic tumors noted in the patients in the WAIT Group (p less than 0.02); nevertheless, if the rate of malignant transformation was examined from time of diagnosis, no differences were noted between the patients in the two groups. Similarly, no difference in survival or quality of life could be demonstrated from time of radiographic diagnosis. Therefore, we could not demonstrate that deferring therapy worsens outcome for these patients.

Neurologic complications of systemic lymphoma

Lymphoma denotes a heterogeneous group of neoplasms derived from lymphoreticular tissues. It can cause neurologic symptoms by infiltrating into the meninges or brain parenchyma. Alternatively, lymphomas may metastasize to bone or infiltrate into the epidural space via intervertebral foramina to cause neurologic dysfunction by compressing adjacent CNS structures. These direct effects can occur at any time during the disease process; most distressingly, meningeal infiltration may be the initial site of relapse after a complete remission. Diffuse and more undifferentiated lymphomas are much more likely to be responsible for producing either meningeal infiltration or intraparenchymal lesions. Direct CNS invasion by lymphoma is associated with significant patient morbidity and short survival despite intensive therapy; whether this manifestation of lymphoma can be prevented by prophylactic CNS treatment remains uncertain. CNS complications may also occur as a result of indirect effects of lymphoma. Therefore, CNS dysfunction may develop as a result of infections that occur secondary to immunosuppression, as a result of antineoplastic therapies, or as a result of true paraneoplastic syndromes. It is important to distinguish between these indirect effects and tumor progression because their recognition permits frequently available appropriate treatment modalities to be administered.

Neuromuscular complications of systemic cancer

In patients with cancer, neuromuscular dysfunction often develops as a result of some combination of direct effects of the cancer, from complications of therapy, or from paraneoplastic syndromes. Direct effects include leptomeningeal involvement by tumors (most frequently of the breast and lung) causing polyradiculopathy and compressive brachial and lumbar plexopathies that produce distinctive and typically painful syndromes. The differentiation between radiation and tumor-associated brachial plexopathies may be difficult, however. Peripheral neuropathy is an important dose-limiting toxic side effect of two commonly utilized agents, vincristine and cisplatin. Recent studies have suggested that this complication may be ameliorated or even prevented by prophylactic administration of protective agents. Finally, cancer can cause neuromuscular dysfunction through more remote effects and can produce a variety of paraneoplastic syndromes that include subacute sensory neuropathy. Lambert-Eaton myasthenic syndrome, and the neuropathy associated with paraproteinemia. In some syndromes, the presence of specific antibodies that cross-react with both neuromuscular tissues and primary tumors strongly suggests an immune-mediated pathogenesis. In some patients, immunosuppressive therapies and plasmapheresis may relieve symptoms.

Coexistence of Lambert-Eaton myasthenic syndrome and subacute cerebellar degeneration: differential effects of treatment

A 61-year-old woman presented with two paraneoplastic neurologic disorders--Lambert-Eaton myasthenic syndrome (LEMS) and subacute cerebellar degeneration (SCD)--that antedated the diagnosis of small-cell carcinoma of the lung by 15 months. Plasmapheresis initiated before the identification of the tumor had a beneficial effect on LEMS but did not affect the SCD. Chemotherapy administered for treatment of the primary tumor was also associated with improvement of LEMS but, like plasmapheresis, had no effect on SCD. While the pathogenesis of both LEMS and SCD is thought to be mediated predominantly by humoral immune factors, a differential therapeutic response indicates that mechanisms of tissue damage or susceptibility to tissue injury, or both, differ in these two disorders.

Potent cytotoxicity of an antihuman transferrin receptor-ricin A-chain immunotoxin on human glioma cells in vitro

The cytotoxic effects of an antihuman transferrin receptor monoclonal antibody-ricin A-chain conjugate (anti-TfR-A) immunotoxin on glioma cells were assessed in vitro. Five human glioma cell lines were studied; three were derived from surgical explants (MG-1, MG-2, MG-3) and two were well characterized established glioma cells (U-87 MG, U-373 MG). The C6 rat glioma line served as a nonhuman control. One of six lines (U-373) expressed glial fibrillary acidic protein, as assessed by immunohistochemistry. All five human lines expressed human transferrin receptor, as assessed by flow cytometry; no human transferrin receptor was demonstrable on rat C6 cells. Potent inhibition of protein synthesis was found after an 18-h incubation with anti-TfR-A. Fifty % inhibitory concentration (IC50) values for human glioma cells ranged from 1.9 X 10(-9) to 1.8 X 10(-8) M. In contrast, no significant inhibition of leucine incorporation was observed when anti-TfR-A was tested on rat cells (IC50 greater than 10(-7) M) or when a control immunotoxin directed against carcinoembryonic antigen was substituted for anti-TfR-A on human glioma cells (IC50 greater than 10(-7) M). Coincubation with the carboxylic ionophore monensin (10(-7) M) decreased the IC50 of anti-TfR-A against human glioma lines from 16- to 842-fold (range, 7.0 X 10(-12) to 1.5 X 10(-10) M). In contrast, an IC50 of greater than 10(-7) M was obtained when C6 cells were incubated with anti-TfR-A and monensin. Anti-TfR-A immunotoxins potentiated by monensin are extremely potent in vitro cytotoxins for human glioma cells.

Brain tumor presenting as an acute pure motor hemiparesis

Acute pure motor hemiparesis is a clinical syndrome of isolated hemiparesis usually related to lacunar infarction, although other etiologies have been described. We recently encountered three patients with the abrupt onset of pure motor hemiparesis as the initial manifestation of primary or metastatic brain tumor. In each patient, early computed tomography demonstrated a nonhemorrhagic, right frontal, enhancing mass lesion. While the mechanism whereby brain tumor may present abruptly and simulate a stroke remains uncertain, these cases illustrate that pure motor hemiparesis can be the initial symptom of intracranial tumor. Early computed tomography or magnetic resonance imaging is suggested for all patients who present acutely with pure motor hemiparesis.

Tumor-associated aphasia in left hemisphere primary brain tumors: the importance of age and tumor grade

Although one-quarter of patients with primary brain tumors have language disturbances at the time of initial presentation, the factors contributing to their aphasia are not clear. A group of 32 patients with primary tumors of the left hemisphere was collected retrospectively and the relationship between clinical, radiographic, and pathologic factors and tumor-associated aphasia was examined. We assessed language function before beginning any treatment including steroids. The factor that best predicted language disturbance was greater patient age; the only other significant factor was tumor grade. Tumor size made a nearly significant impact, but tumor location within the left hemisphere did not correlate with aphasia.

Effects of beta-funaltrexamine on radiolabeled opioid binding

beta-Funaltrexamine (beta-FNA) potently competed with the binding of a series of radiolabeled opiates and opioid peptides in standard binding assays with IC50 values under 10 nM. In addition, higher concentrations of beta-FNA produced an irreversible inhibition of binding which was relatively selective for mu receptors; delta binding was not affected much. The production of irreversible inhibition of [3H]dihydromorphine binding required concentrations of beta-FNA over 10-fold higher than beta-FNA concentrations needed in standard competition studies. Both mu 1 and mu 2 sites were irreversibly inhibited by beta-FNA, but mu 1 sites were more sensitive. The reversible and irreversible inhibition in these in vitro binding assays by beta-FNA were quite similar to naloxonazine. However, the activity of beta-FNA in the guinea-pig ileum suggests that it may not distinguish between mu 1 and mu 2 receptors as effectively as naloxonazine in bioassays and in vivo.

Neuropeptides and their role in nociception and analgesia

The authors highlight the potential importance of neuropeptides as clinical tools in the study and treatment of pain. Although many questions remain unanswered, it is encouraging that several clinical and experimental advances have shed new light on the neuropharmacology of nociception and have prompted new hope for more effective treatments of such diverse problems as chronic intractable pain, migraine, and drug dependency. Within the next few years, it is anticipated that further work in this area will lead to better basic and clinical understanding of these important clinical problems.

Synchronous occurrence of glioblastoma multiforme in a husband and wife

Glioblastomas developed within two years of each other in an otherwise unrelated married couple in their fifties. There was a daughter who died of Hodgkin's disease but no other unusual incidence of cancer in either siblings, parents or other children. No clear etiology of risk factors for brain tumor were identified. The development of such conjugal tumors, although apparently rare, raises important etiologic questions.

Quantitative autoradiography of the development of mu opiate binding sites in rat brain

The regional developmental appearance of mu binding sites in rat brain was examined by quantitative autoradiography of 3H-dihydromorphine binding in rats 2, 14, 21, and 28 days old. Labeling with 3H-dihydromorphine was heterogeneous in adult rat brains, as previously reported by other laboratories. Levels of 3H-dihydromorphine binding ranged from approximately 250 nCi/g tissue in the interpeduncular nucleus and 100 nCi/g tissue in the habenula to 40 nCi/g tissue in the hypothalamus and periaqueductal gray. Some areas, particularly white matter regions, had no detectable specific binding. The density of 3H-dihydromorphine binding increased in all regions between 2 and 28 days of age. The increases in 3H-dihydromorphine binding in various regions of rat brain developed at different rates. Maximal densities were seen by 14 days of age in most regions examined, including the caudate, hippocampus, amygdala, and hypothalamus. Binding in the medial thalamus and quadrigeminal plate, however, did not reach maximal levels until 21 days. Although quantitative autoradiography offers major advantages in the examination of the regional distribution of opiate binding sites, variability both between sections from the same brain and between sections from different brains demonstrate some of the difficulties associated with this type of experimental approach.

Biochemical characterization of high-affinity 3H-opioid binding. Further evidence for Mu1 sites

In saturation studies with [3H]dihydromorphine, unlabeled D-Ala2-D-Leu5-enkephalin (1 nM) inhibited the high-affinity binding component far more potently than the lower-affinity one. Similarly, morphine (1 nM) inhibited the higher-affinity binding of 3H-D-Ala2-D-Leu5-enkephalin to a greater extent than its lower-affinity binding component, consistent with a common high-affinity binding site for opiates and enkephalins. Treatment of tissue with either trypsin (1 microgram/ml) or N-ethylmaleimide (25 microM) effectively eliminated the high-affinity binding component of a series of 3H-opiates and opioid peptides. Competition studies following both treatments were consistent with a common high-affinity binding site. Both treatments also eliminated the ability of low morphine concentrations (less than 1 nM) to inhibit 3H-D-Ala2-D-Leu5-enkephalin binding and of low D-Ala2-D-Leu5-enkephalin concentrations (less than 1 nM) to inhibit [3H]dihydromorphine binding. Protection experiments examining N-ethylmaleimide (25 microM) inhibition of [3H]dihydromorphine binding showed significant protection (p less than 0.002) by both unlabeled D-Ala2-D-Leu5-enkephalin and morphine (both at 1 nM). When studied together, both naloxonazine and N-ethylmaleimide inhibited [3H]dihydromorphine binding to a similar extent. Equally important, tissue previously treated with naloxonazine was far less sensitive to N-ethylmaleimide than was untreated control tissue, consistent with the possibility that both treatments affected the same site. Together, these results support the concept of a common high-affinity binding site for opiates and opioid peptides.

Biochemical and pharmacological evidence for opioid receptor multiplicity in the central nervous system

Evidence from a variety of experimental models has suggested the existence of mu 1, mu 2 and delta binding sites for morphine and the enkephalins in the central nervous system. Additional biochemical experiments now support this concept of a common high affinity site for opiates and opioid peptides. Mu sites have now been implicated in a number of pharmacological actions, including supraspinal analgesia, prolactin release, and catalepsy, but not in others (spinal analgesia, respiratory depression, and the guinea pig ileum). The hypothesis of mu 1 sites was supported by the unique opioid meptazinol, which selectively bound to mu 1 sites. As expected from its mu 1 binding selectivity, its analgesic actions in the mouse, localized supraspinally, were antagonized by the selective mu 1 antagonist naloxonazine and it had no respiratory depressant actions. Other binding studies suggested the presence of discrete SKF10,047-selective (KD approximately 5 nM) binding sites in rat brain which differed from both kappa sites and the previously reported PCP-binding sigma sites. Additional binding and autoradiographical studies have also implied the presence of beta-endorphin, or epsilon, sites in the CNS.

Blastomycosis in immunosuppressed patients

Of 78 patients with blastomycosis, 3 patients had received glucocorticoid therapy prior to diagnosis and 3 others had an underlying hematologic malignancy (chronic lymphocytic leukemia, chronic myelogenous leukemia, multiple myeloma). The clinical picture in these 6 patients was similar to blastomycosis in nonimmunosuppressed patients (in contrast to histoplasmosis or coccidioidomycosis in immunosuppressed patients in whom a distinct clinical syndrome is often seen). The patients presented with chronic pulmonary infiltrates or with isolated skin ulcers. The response to therapy was good if the diagnosis was made early. Blastomycosis can occur in immunosuppressed patients. However, the spectrum of underlying illness is not that seen in opportunistic histoplasmosis or coccidioidomycosis, where patients with T-cell defects predominate. Possible explanations for the rarity of blastomycosis in more classically T-cell-immunosuppressed patients are discussed.

Vasopressin concentrations in hypophysial portal plasma: insignificant reduction following removal of the posterior pituitary gland

This study was designed to determine the relative contribution of vasopressin-secreting nerve terminals in the median eminence compared to those in posterior pituitary to the high concentrations of the hormone in hypophysial portal blood. Vasopressin was measured by radioimmunoassay in plasma obtained by microcannulation of individual long portal veins of 8 intact male Long-Evans rats (2.0 +/- 0.44 ng/ml SEM), and in 8 in which the posterior pituitary was removed just prior to collection (1.5 +/- 0.3 ng/ml SEM). Since there was no significant difference /p = 0.23, NS) in the concentration of vasopressin in portal plasma after removal of the posterior pituitary gland, these results suggest that the direct vasopressin pathway to the median eminence is the major source of vasopressin in portal blood of the rat.

Self-limited blastomycosis: a report of thirteen cases

Blastomycosis is not generally recognized to be a self-limited pulmonary infection. We report 13 patients with blastomycosis who followed a self-limited course. Presenting complaints were usually those of an acute pulmonary infection with fever, productive cough, and pleurtiic chest pain. The duration of symtpoms before diagnosis was usuallms were variable and not diagnostic. The blastomycin skin test and complement-fixing serologies to blastomycin were generally not helpful. In all patients the diagnosis was made by either cultural or visual identification of the organism from sputum, bronchial washings, or pleural fluid. All patients were improving both clinically and by chest roentgenograms by the time the diagnosis was reached, and thus therapy was withheld. Follow-up of these 13 patients ranged from 5 months to 8 yr (mean, 43 months), and in no instance has there been any evidence of reactivation of the illness.