Adhesion molecules and malignant gliomas: implications for tumorigenesis

Adhesion molecules, a family of cell-surface molecules, are likely to be of central importance in mediating cell-extracellular matrix and specific cell-cell interactions within both neoplastic and inflammatory sites. The recently discovered expression of adhesion molecules on glioma cells, tumor-infiltrating lymphocytes, and endothelial cells within the tumor offers insight into the molecular basis of the interactions both between the glioma cell and surrounding heterologous cell types within the tumor environment, and between the tumor cell and the extracellular matrix. Such interactions suggest that these molecules may play roles in the homing of immune cells to these tumors and in regulating the extent of local tumor invasion. The ability to modulate adhesion molecule expression on either immune cells or their respective ligands on gliomas provides an approach to modify cell-cell interactions that may be used to increase tumor kill by the immune system. A similar approach in the modulation of adhesion molecules involved in tumor cell adhesion to the extracellular matrix or endothelial cells may be a method to limit local invasion in these lesions.

Cysticercosis cerebri

With increasing immigration from endemic regions, the incidence of cysticercosis in North America is rising. This fascinating disease with its varied presentations may pose complex management dilemmas whose resolutions often require a combined approach to treatment involving medical and, in some cases, selected surgical intervention. The treatment course must be individualized depending on the symptomatology, anatomic location of the cysts, and host inflammatory response.

Enhanced protein kinase C activity correlates with the growth rate of malignant gliomas in vitro

Direct measurement of protein kinase C (PKC) activity in vitro revealed a significant increase in the activity of the enzyme in all human malignant glioma lines examined and the rat C6 tumor in comparison with control nonneoplastic astrocyte and mixed glial cultures. The total and particulate PKC activity in these cell types correlated strongly [r = 0.98 (P less than 0.001) and 0.94 (P = 0.002), respectively] with the maximal growth rates as measured by 3H-thymidine incorporation in each of the samples. An alteration in the growth rate of an individual glioma line (A172) by varying the serum concentration in the growth medium produced comparative changes in the measured PKC activity. The addition of the phorbol ester phorbol-12-myristate-13-acetate to this tumor line under high serum conditions produced down-regulation of the enzyme, which was accompanied by a corresponding reduction in thymidine incorporation. The administration of the PKC inhibitor staurosporine produced a dose-related decrease in the basal proliferation rate of glioma lines A172 and C6, as measured by 3H-thymidine uptake and confirmed by flow cytometry, indicating that the high intrinsic PKC activity is amenable to pharmacological manipulation. Cytofluorometric deoxyribonucleic acid cell cycle analysis of the tumors treated with PKC modulators demonstrated that reduced proliferation rates were caused by an inhibition of entrance into the deoxyribonucleic acid synthesis (S) phase (decrease in proliferative index), supporting the evidence that these modulators are not slowing the tumor growth in a nonspecific cytotoxic manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Malignant glioma modulation of immune function: relative contribution of different soluble factors

We analyzed a series of human glioma cell lines with regard to establishing what variables may contribute to their overall functional immunomodulating capability. We observed that supernatants derived from the gliomas, but not those from non-malignant human astrocyte cultures, suppressed lymphocyte proliferation. The extent of suppression elicited differed between tumors and for the same tumor depending upon its growth phase. For individual gliomas, supernatants from cultures approaching or at confluency elicited maximal lymphocyte suppression. For the series of tumors, levels of production of the immunosuppressive molecules transforming growth factor beta 2 and prostanoids (prostaglandin E2) did not correlate with the levels of functional suppression observed at any of the different growth phases. In some cases, glioma cultures grown in the presence of indomethacin to abolish prostanoid synthesis resulted in supernatants with net stimulatory activity. Our results indicate that malignant transformation of astrocytes is associated with acquisition of immunosuppressive capability which is determined by the combined effect of multiple immunomodulatory soluble factors, inhibitory or enhancing, and is dependent on the growth phase of the tumor.

Inhibition of growth of established human glioma cell lines by modulators of the protein kinase-C system

The protein kinase-C (PKC) second messenger system contributes to regulation of cell growth and differentiation. This study was undertaken to examine the effects of modulators of the PKC enzyme system on the state of differentiation and proliferation rates of human gliomas in vitro. The administration of the PKC-activating phorbol esters 4-beta-phorbol-12,13-dibutyrate (PDB) and phorbol-12-myristate-13-acetate (PMA) resulted in a dose-related inhibition of growth of human glioma cell lines in vitro as measured by 3H-thymidine uptake. The synthetic nonphorbol PKC activator (SC-9) produced an even more pronounced decrease of 3H-thymidine uptake. Diacylglycerol, an endogenous activator of the system, applied externally, transiently decreased the proliferation, in concordance with its short-lived existence in vivo. Conversely, the administration of 4-alpha-phorbol-12,13-didecanoate (alpha-PDD), a phorbol ester that binds but does not activate the enzyme, had no effect on the proliferation rate. At the dosages that maximally decreased proliferation, there was no evidence of direct glioma cell lysis induced by these agents as measured by a chromium-release assay. Immunocytochemical analysis and cytofluorometric measurement of glial fibrillary acidic protein (GFAP) staining in the treated cultures revealed an increase in GFAP staining over control cultures. In contrast to the response of glioma cells, nonmalignant human adult astrocytes treated with the PKC activators responded by increasing their proliferation rate. The authors postulate that the diametrically opposed effects of PKC activators on nonmalignant astrocytes versus glioma growth may be due to a high intrinsic PKC activity in glioma cells, with resultant down-regulation of enzyme activity following the administration of the pharmacological activators.

Utilization of unilateral and bilateral stereotactically placed adrenomedullary-striatal autografts in parkinsonian humans: rationale, techniques, and observations

A limited clinical pilot study involving an amalgam of specialized disciplines including neurology, neuropharmacology, neuropsychology, neurosurgery, neuroanesthesia, neuroradiology, surgical pathology, neuropathology, and urological surgery was organized to clarify issues related to patient selection, optimization of grafting materials, design of a safe, effective, standardized, and reproducible surgical technique, and possible modification of clinical patterns. After initial assessment of 82 Parkinsonian patients for periods of 6 to 20 months, 10 (age, 39-68 years) were selected for unilateral or bilateral adrenomedullary autografts to the caudate nucleus with ependymal and cerebrospinal fluid contact, employing image-directed stereotactic methods. Selection was made only after clear definition of clinical pattern and optimization of medication responses. Adrenal glands were harvested by a retroperitoneal approach (mean estimated blood loss less than 75 ml). Care was taken to maximize the graft content of medullary tissue. Stereotactic methods afforded standardized, reproducible, precise targeting and transit trajectory with unilateral or bilateral placement of materials within the striatum (tissue volume, 80 mm3) with access to the ventricular fluid of the frontal horn. Considerable variability in satisfactory donor medullary tissue was encountered. One patient did not undergo grafting because of unsatisfactory medullary tissue. No significant surgical complications were noted and all patients were ready for discharge 7 days after surgery. One patient who manifested no apparent clinical change died 6 weeks after bilateral grafting of unrelated causes during a lithotripsy procedure. Postmortem examination disclosed precise graft placement with a paucity of structurally preserved medullary cells. Postoperative observations, including parameters of clinical observation, medication schedules and records, patient and family commentaries, and imaging studies (computed tomograms and single photon emission computed tomograms), have been made for periods from 16 to 20 months. Sustained improvement in preexisting clinical patterns and reduction in drug requirements were observed in 4 of 8 patients. No increased benefit could be ascribed to bilateral graft placement. These observations would indicate a safe, and reproducible surgical method. In addition, the clinical observations indicate favorable alterations in the established pattern of the disorder, which would justify further cautious exploration of alternate donor sources or refinements of biological graft site manipulations.

Initial experience related to the use of the Cosman-Roberts-Wells stereotactic instrument. Technical note

Initial experience with a new arc-radius design of stereotactic frame that interfaced with the existing components of the Brown-Roberts-Wells instrument is reported. Over a 6-month period, 32 procedures were performed on 23 males and nine female patients (mean age 32 years); these included 27 stereotactic biopsy procedures, two stereotactic implantations of cyst catheter reservoirs, two ventriculoscopic aspirations of third ventricular colloid cysts, and one stereotactic aspiration of a craniopharyngioma. In all cases successful targeting was achieved and verified by postoperative computerized tomography. There were no operation-related complications. This new frame offers rapid and accurate targeting and is a useful adjunct to the stereotactic armamentarium.

Pituitary gland metastasis from adenocarcinoma of the prostate. Case report

A case of prostatic carcinoma metastasis to the pituitary gland is reported. The presentation and rarity of such a lesion is addressed. The literature review yielded only isolated case reports of symptomatic brain metastases unassociated with bone disease from adenocarcinoma of the prostate. The management options of such a lesion are discussed.