Spatial characteristics of newly diagnosed grade 3 glioma assessed by magnetic resonance metabolic and diffusion tensor imaging

The spatial heterogeneity in magnetic resonance (MR) metabolic and diffusion parameters and their relationship were studied for patients with treatment-naive grade 3 gliomas. MR data were evaluated from 51 patients with newly diagnosed grade 3 gliomas. Anatomic, diffusion, and metabolic imaging data were considered. Variations in metabolite levels, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were evaluated in regions of gadolinium enhancement and T2 hyperintensity as well as regions with abnormal metabolic signatures. Contrast enhancement was present in only 21 of the 51 patients. When present, the enhancing component of the lesion had higher choline-to-N-acetylaspartate index (CNI), higher choline, lower N-acetylaspartate, similar creatine, similar ADC and FA, and higher lactate/lipid than the nonenhancing lesion. Regions with CNI ≥ 4 had higher choline, lower N-acetylaspartate, higher lactate/lipid, higher ADC, and lower FA than normal-appearing white matter and regions with intermediate CNI values. For lesions that exhibited gadolinium enhancement, the metabolite levels and diffusion parameters in the region of enhancement were consistent with it corresponding to the most abnormal portion of the tumor. For nonenhancing lesions, areas with CNI ≥ 4 were the most abnormal in metabolic and diffusion parameters. This suggests that the region with the highest CNI might provide a good target for biopsies for nonenhancing lesions to obtain a representative histologic diagnosis of its degree of malignancy. Metabolic and diffusion parameter levels may be of interest not only for directing tissue sampling but also for defining the targets for focal therapy and assessing response to therapy.     

Benign and atypical meningioma metabolic signatures by high-resolution magic-angle spinning molecular profiling

Meningiomas are neoplasms that arise from the leptomeningeal covering of the brain and spinal cord, accounting for 15%-20% of CNS tumors. The WHO classifies meningiomas into three histological grades: benign, atypical, and anaplasic in accordance with the clinical prognosis. Atypical and anaplasic meningiomas tend to recur. Sometimes, meningiomas with histological diagnosis of benign meningioma show clinical characteristics of atypical meningioma. In this context, high-resolution magic-angle spinning (HR-MAS) spectroscopy of intact tissue from brain tumor biopsies has shown great potential as a support diagnostic tool. In this work, we show differences between benign and atypical meningiomas in HR-MAS molecular profiles of meningioma biopsies. Metabolic differences between meningioma grades include changes in the levels of glutathione. Glutathione role in cancer is still unclear, as it may act both as protective and pathogenic factor. Glutamine and glutamate, which are related to glutathione metabolism and have been associated with tumor recurrence, are also increased in atypical meningiomas. Other metabolites associated with tumor malignancy that show statistically significant differences between benign and atypical meningiomas include phosphocholine and phosphoethanolamine. Overall, this work suggests that the additional information obtained by NMR metabolomics applied to biopsies of human meningiomas may be useful for assessing tumor grade and determining optimum treatment strategies.     

FDTD analysis of a noninvasive hyperthermia system for brain tumors

ABSTRACT: BACKGROUND: Hyperthermia is considered one of the new therapeutic modalities for cancer treatment and is based on the difference in thermal sensitivity between healthy tissues and tumors. During hyperthermia treatment, the temperature of the tumor is raised to 40--4[DEGREE SIGN]C for a definite period resulting in the destruction of cancer cells. This paper investigates design, modeling and simulation of a new non-invasive hyperthermia applicator system capable of effectively heating deep seated as well as superficial brain tumors using inexpensive, simple, and easy to fabricate components without harming surrounding healthy brain tissues. METHODS: The proposed hyperthermia applicator system is composed of an air filled partial half ellipsoidal chamber, a patch antenna, and a head model with an embedded tumor at an arbitrary location. The irradiating antenna is placed at one of the foci of the hyperthermia chamber while the center of the brain tumor is placed at the other focus. The finite difference time domain (FDTD) method is used to compute both the SAR patterns and the temperature distribution in three different head models due to two different patch antennas at a frequency of 915 MHz. RESULTS: The obtained results suggest that by using the proposed noninvasive hyperthermia system it is feasible to achieve sufficient and focused energy deposition and temperature rise to therapeutic values in deep seated as well as superficial brain tumors without harming surrounding healthy tissue. CONCLUSIONS: The proposed noninvasive hyperthermia system proved suitable for raising the temperature in tumors embedded in the brain to therapeutic values by carefully selecting the systems components. The operator of the system only needs to place the center of the brain tumor at a pre-specified location and excite the antenna at a single frequency of 915 MHz. Our study may provide a basis for a clinical applicator prototype capable of heating brain tumors.     

Immunocytochemical localization of platelets in baboon hepatic sinusoids using monoclonal mouse anti-human platelet glycoprotein IIIa following induction of thrombocytopenia.

A commercially available mouse monoclonal antibody to human platelet glycoprotein IIIa was used to demonstrate sequestration of platelets in hepatic biopsies obtained from baboons following intravenous infusion of echistatin, a novel fibrinogen receptor antagonist derived from the venom of the snake Echis carinatus. Biopsies of liver and spleen were taken prior to administration of echistatin. The hepatic biopsies were either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen were snap-frozen. During infusion of echistatin (2.3 micrograms/kg/min), circulating platelet counts decreased from 331,000/mm3 to 167,000/mm3. Selective sequestration within the liver was confirmed using whole body gamma camera imaging to demonstrate 111Indium-oxine labeled platelet accumulation within the liver during the thrombocytopenic episode. Hepatic biopsies were again taken and either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen and inguinal lymph node were also snap-frozen. Platelet rich plasma smears, included as positive controls, dewaxed paraffin sections, and cryosections of liver, spleen, and lymph node were stained with monoclonal mouse anti-human platelet glycoprotein IIIa using an avidin biotinylated peroxidase complex (ABC) technique. Prior to infusion of echistatin, platelet staining within the liver was minimal. After echistatin infusion, hepatic cryosections showed prominent platelet staining within hepatic sinusoids. No localization was shown in lymph node, however, the spleen showed prominent platelet staining both before and after echistatin infusion. Platelet rich plasma smears were intensely positive. No prominent platelet staining was observed in formalin-fixed, paraffin-embedded material. Thus, this immunocytochemical technique may help localize platelets in cryosections of tissues from baboons and other primate species.     

Identification of distinctive features in human intracranial tumors by label‐free nonlinear multimodal microscopy

Nonlinear multimodal microscopy offers a series of label‐free techniques with potential for intraoperative identification of tumor borders in situ using novel endoscopic devices. Here, we combined coherent anti‐Stokes Raman scattering, two‐photon excited fluorescence (TPEF) and second harmonic generation imaging to analyze biopsies of different human brain tumors, with the aim to understand whether the morphological information carried by single field of view images, similar to what delivered by present endoscopic systems, is sufficient for tumor recognition. We imaged 40 human biopsies of high and low grade glioma, meningioma, as well as brain metastases of melanoma, breast, lung and renal carcinoma, in comparison with normal brain parenchyma. Furthermore, five biopsies of schwannoma were analyzed and compared with nonpathological nerve tissue. Besides the high cellularity, the typical features of tumor, which were identified and quantified, are intracellular and extracellular lipid droplets, aberrant vessels, extracellular matrix collagen and diffuse TPEF. Each tumor type displayed a particular morphochemistry characterized by specific patterns of the above‐mentioned features. Nonlinear multimodal microscopy performed on fresh unprocessed biopsies confirmed that the technique has the ability to visualize tumor structures and discern normal from neoplastic tissue likewise in conditions close to in situ.      

Vanucizumab mode of action: Serial biomarkers in plasma,tumor, and skin-wound-healing biopsies

Vanucizumab is a novel bispecific antibody inhibiting vascular endothelial growth factor (VEGF-A) and angiopoietin-2 (Ang-2) that demonstrated safety and anti-tumor activity in part I of a phase I study of 42 patients with advanced solid tumors. Part II evaluated the pharmacodynamic effects of vanucizumab 30 or 15 mg/kg every 2 weeks in 32 patients. Serial plasma samples, paired tumor, and skin-wound-healing biopsies were taken over 29 days to evaluate angiogenic markers. Vanucizumab was associated with marked post-infusion reductions in circulating unbound VEGF-A and Ang-2. By day 29, tumor samples revealed mean reductions in density of microvessels (−32.2%), proliferating vessels (−47.9%) and Ang-2 positive vessels (−62.5%). Skin biopsies showed a mean reduction in density of microvessels (−49.0%) and proliferating vessels (−25.7%). Gene expression profiling of tumor samples implied recruitment and potential activation of lymphocytes. Biopsies were safely conducted. Vanucizumab demonstrated a consistent biological effect on vascular-related biomarkers, confirming proof of concept. Skin-wound-healing biopsies were a valuable surrogate for studying angiogenesis-related mechanisms.     

Response Prediction to Neoadjuvant Chemotherapy: Comparison between Pre-Therapeutic Gene Expression Profiles and In Vitro Chemosensitivity Assay

Although the use of (neo-)adjuvant chemotherapy in breast cancer patients has resulted in improved outcome, not all patients benefit equally. We have evaluated the utility of an in vitro chemosensitivity assay in predicting response to neoadjuvant chemotherapy. Pre-therapeutic biopsies were obtained from 30 breast cancer patients assigned to neoadjuvant epirubicin 75 mg/m2 and docetaxel 75 mg/m2 (Epi/Doc) in a prospectively randomized clinical trial. Biopsies were subjected to a standardized ATP-based Epi/Doc chemosensitivity assay, and to gene expression profiling. Patients then received 3 cycles of chemotherapy, and response was evaluated by changes in tumor diameter and Ki67 expression. The efficacy of Epi/Doc in vitro was correlated with differential changes in tumor cell proliferation in response to Epi/Doc in vivo (p = 0.0011; r = 0.73670, Spearmańs rho), but did not predict for changes in tumor size. While a pre-therapeutic gene expression signature identified tumors with a clinical response to Epi/Doc, no such signature could be found for tumors that responded to Epi/Doc in vitro, or tumors in which Epi/Doc exerted an antiproliferative effect in vivo. This is the first prospective clinical trial to demonstrate the utility of a standardized in vitro chemosensitivity assay in predicting the individual biological response to chemotherapy in breast cancer.     

Diversity of Metabolic Patterns in Human Brain Tumors: Enzymes of Energy Metabolism and Related Metabolites and Cofactors

Biopsies from 15 human gliomas, five meningiomas, four Schwannomas, one medulloblastoma, and four normal brain areas were analyzed for 12 enzymes of energy metabolism and 12 related metabolites and cofactors. Samples, 0.01-0.25 microgram dry weight, were dissected from freeze-dried microtome sections to permit all the assays on a given specimen to be made, as far as possible, on nonnecrotic pure tumor tissue from the same region. Great diversity was found with regard to both enzyme activities and metabolite levels among individual tumors, but the following generalities can be made. Activities of hexokinase, phosphorylase, phosphofructokinase, glycerophosphate dehydrogenase, citrate synthase, and malate dehydrogenase levels were usually lower than in brain; glycogen synthase and glucose-6-phosphate dehydrogenase were usually higher; and the averages for pyruvate kinase, lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and beta-hydroxyacyl coenzyme A dehydrogenase were not greatly different from brain. Levels of eight of the 12 enzymes were distinctly lower among the Schwannomas than in the other two groups. Average levels of glucose-6-phosphate, lactate, pyruvate, and uridine diphosphoglucose were more than twice those of brain; 6-phosphogluconate and citrate were about 70% higher than in brain; glucose, glycogen, glycerol-1-phosphate, and malate averages ranged from 104% to 127% of brain; and fructose-1,6-bisphosphate and glucose-1,6-bisphosphate levels were on the average 50% and 70% those of brain, respectively.     

Specific Visualization of Glioma Cells in Living Low-Grade Tumor Tissue

Background

The current therapy of malignant gliomas is based on surgical resection, radio-chemotherapy and chemotherapy. Recent retrospective case-series have highlighted the significance of the extent of resection as a prognostic factor predicting the course of the disease. Complete resection in low-grade gliomas that show no MRI-enhanced images are especially difficult. The aim in this study was to develop a robust, specific, new fluorescent probe for glioma cells that is easy to apply to live tumor biopsies and could identify tumor cells from normal brain cells at all levels of magnification.

Methodology/Principal Findings

In this investigation we employed brightly fluorescent, photostable quantum dots (QDs) to specifically target epidermal growth factor receptor (EGFR) that is upregulated in many gliomas. Living glioma and normal cells or tissue biopsies were incubated with QDs coupled to EGF and/or monoclonal antibodies against EGFR for 30 minutes, washed and imaged. The data include results from cell-culture, animal model and ex vivo human tumor biopsies of both low-grade and high-grade gliomas and show high probe specificity. Tumor cells could be visualized from the macroscopic to single cell level with contrast ratios as high as 1000: 1 compared to normal brain tissue.

Conclusions/Significance

The ability of the targeted probes to clearly distinguish tumor cells in low-grade tumor biopsies, where no enhanced MRI image was obtained, demonstrates the great potential of the method. We propose that future application of specifically targeted fluorescent particles during surgery could allow intraoperative guidance for the removal of residual tumor cells from the resection cavity and thus increase patient survival.     

Drug-induced skin reactions and acute cutaneous graft-versus-host reaction: a comparative immunohistochemical study

Skin biopsies from eight patients with drug-induced dermatitis have been compared with skin biopsies from 16 patients developing skin lesions (acute graft versus host-reaction and/or drug-induced reaction) after bone marrow transplantation. Biopsies were investigated using immunohistochemistry and several monoclonal antibodies. Morphological and immunohistochemical patterns in skin biopsies of both groups were very similar. The only difference seen was a reduced number of epidermal Langerhans cells with poorly developed dendrites in skin biopsies taken from patients who underwent bone marrow transplantation. If the latter finding is due to the cytotoxic drug regimen administered before bone marrow transplantation, as previously stated, we doubt the usefulness of skin biopsies in the differential diagnosis of acute graft-versus-host reaction and drug-induced skin lesions.     

A novel method for volumetric MRI response assessment of enhancing brain tumors

Current radiographic response criteria for brain tumors have difficulty describing changes surrounding postoperative resection cavities. Volumetric techniques may offer improved assessment, however usually are time-consuming, subjective and require expert opinion and specialized magnetic resonance imaging (MRI) sequences. We describe the application of a novel volumetric software algorithm that is nearly fully automated and uses standard T1 pre- and post-contrast MRI sequences. T1-weighted pre- and post-contrast images are automatically fused and normalized. The tumor region of interest is grossly outlined by the user. An atlas of the nasal mucosa is automatically detected and used to normalize levels of enhancement. The volume of enhancing tumor is then automatically calculated. We tested the ability of our method to calculate enhancing tumor volume with resection cavity collapse and when the enhancing tumor is obscured by subacute blood in a resection cavity. To determine variability in results, we compared narrowly-defined tumor regions with tumor regions that include adjacent meningeal enhancement and also compared different contrast enhancement threshold levels used for the automatic calculation of enhancing tumor volume. Our method quantified enhancing tumor volume despite resection cavity collapse. It detected tumor volume increase in the midst of blood products that incorrectly caused decreased measurements by other techniques. Similar trends in volume changes across scans were seen with inclusion or exclusion of meningeal enhancement and despite different automated thresholds for tissue enhancement. Our approach appears to overcome many of the challenges with response assessment of enhancing brain tumors and warrants further examination and validation.     

Group Independent Component Analysis and Functional MRI Examination of Changes in Language Areas Associated with Brain Tumors at Different Locations

Object

This study investigates the effect of tumor location on alterations of language network by brain tumors at different locations using blood oxygenation level dependent (BOLD) fMRI and group independent component analysis (ICA).

Subjects and Methods

BOLD fMRI data were obtained from 43 right handed brain tumor patients. Presurgical mapping of language areas was performed on all 43 patients with a picture naming task. All data were retrospectively analyzed using group ICA. Patents were divided into three groups based on tumor locations, i.e., left frontal region, left temporal region or right hemisphere. Laterality index (LI) was used to assess language lateralization in each group.

Results

The results from BOLD fMRI and ICA revealed the different language activation patterns in patients with brain tumors located in different brain regions. Language areas, such as Broca’s and Wernicke’s areas, were intact in patients with tumors in the right hemisphere. Significant functional changes were observed in patients with tumor in the left frontal and temporal areas. More specifically, the tumors in the left frontal region affect both Broca’s and Wernicke’s areas, while tumors in the left temporal lobe affect mainly Wernicke’s area. The compensated activation increase was observed in the right frontal areas in patients with left hemisphere tumors.

Conclusion

Group ICA provides a model free alternative approach for mapping functional networks in brain tumor patients. Altered language activation by different tumor locations suggested reorganization of language functions in brain tumor patients and may help better understanding of the language plasticity.     

Immunocytochemical localization of platelets in baboon hepatic sinusoids using monoclonal mouse anti-human platelet glycoprotein IIIa following induction of thrombocytopenia

Summary A commercially available mouse monoclonal antibody to human platelet glycoprotein IIIa was used to demonstrate sequestration of platelets in hepatic biopsies obtained from baboons following intravenous infusion of echistatin, a novel fibrinogen receptor antagonist derived from the venom of the snake Echis carinatus. Biopsies of liver and spleen were taken prior to administration of echistatin. The hepatic biopsies were either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen were snapfrozen. During infusion of echistatin (2.3 µg/kg/min), circulating platelet counts decreased from 331000/mm³ to 167000/mm³. Selective sequestration within the liver was confirmed using whole body gamma camera imaging to demonstrate ¹¹¹Indium-oxine labeled platelet accumulation within the liver during the thrombocytopenic episode. Hepatic biopsies were again taken and either snap-frozen in Freon-22/liquid nitrogen or fixed in 10% neutral buffered formalin. Biopsies of spleen and inguinal lymph node were also snap-frozen. Platelet rich plasma smears, included as positive controls, dewaxed paraffin sections, and cryosections of liver, spleen, and lymph node were stained with monoclonal mouse anti-human platelet glycoprotein IIIa using an avidin biotinylated peroxidase complex (ABC) technique. Prior to infusion of echistatin, platelet staining within the liver was minimal. After echistatin infusion, hepatic cryosections showed prominent platelet staining within hepatic sinusoids. No localization was shown in lymph node, however, the spleen showed prominent platelet staining both before and after echistatin infusion. Platelet rich plasma smears were intensely positive. No prominent platelet staining was observed in formalin-fixed, paraffin-embedded material. Thus, this immunocytochemical technique may help localize platelets in cryosections of tissues from baboons and other primate species.     

Cathepsin D and its prognostic value in neuroepithelial brain tumors

Expression of Cathepsin D (Cath D) in some primary neuroepithelial brain tumors and its prognostic value were studied. The research included 65 samples of human primary neuroepithelial brain tumors. There were 50 glial tumors (10 diffuse astrocytomas (DA), 15 anaplastic astrocytomas (AA), 25 glioblastomas (GB), 15 embryonic tumors (15 medulloblastomas (MB) as well as 5 samples of normal brain tissue. Immunohistochemical method was applied to monitor diffuse positive reaction in the cytoplasm of brain tumor cells, endothelial cells and tumor stromal cells and showed diffuse positive reaction for Cath D in the cytoplasm of brain tumor cells, endothelial cells and stromal cells in all analyzed samples of DA, AA, GB and MB as well as in microglial cells, neurons and in endothelial cells in all analyzed samples of normal brain tissue. Qualitative analysis of Cath D expression in the cytoplasm of brain tumor cells and endothelial cells as well as the percentage of brain tumor cells, endothelial cells and stromal cells immunopositive for Cath D showed that there was difference between analyzed brain tumor groups, but according to statistical tests the difference was not statistically significant. Survival correlated with the percentage of stromal cells immunopositive for Cath D. Survival prognosis was influenced by the percentage of stromal cells immunopositive for Cath D and tumor grade. The obtained results singled out the percentage of stromal cells immunopositive for Cath D as an independent parameter. The results of this research on the prognostic value of Cath D in some primary brain tumors of neuroepithelial origin indicate that there is real possibility to use Cath D as an independent prognostic factor in human glioma progression and thus open up possibilities for further scientific research.     

Delayed Contrast Extravasation MRI for Depicting Tumor and Non-Tumoral Tissues in Primary and Metastatic Brain Tumors

The current standard of care for newly diagnosed glioblastoma multiforme (GBM) is resection followed by radiotherapy with concomitant and adjuvant temozolomide. Recent studies suggest that nearly half of the patients with early radiological deterioration post treatment do not suffer from tumor recurrence but from pseudoprogression. Similarly, a significant number of patients with brain metastases suffer from radiation necrosis following radiation treatments. Conventional MRI is currently unable to differentiate tumor progression from treatment-induced effects. The ability to clearly differentiate tumor from non-tumoral tissues is crucial for appropriate patient management. Ten patients with primary brain tumors and 10 patients with brain metastases were scanned by delayed contrast extravasation MRI prior to surgery. Enhancement subtraction maps calculated from high resolution MR images acquired up to 75 min after contrast administration were used for obtaining stereotactic biopsies. Histological assessment was then compared with the pre-surgical calculated maps. In addition, the application of our maps for prediction of progression was studied in a small cohort of 13 newly diagnosed GBM patients undergoing standard chemoradiation and followed up to 19.7 months post therapy. The maps showed two primary enhancement populations: the slow population where contrast clearance from the tissue was slower than contrast accumulation and the fast population where clearance was faster than accumulation. Comparison with histology confirmed the fast population to consist of morphologically active tumor and the slow population to consist of non-tumoral tissues. Our maps demonstrated significant correlation with perfusion-weighted MR data acquired simultaneously, although contradicting examples were shown. Preliminary results suggest that early changes in the fast volumes may serve as a predictor for time to progression. These preliminary results suggest that our high resolution MRI-based delayed enhancement subtraction maps may be applied for clear depiction of tumor and non-tumoral tissues in patients with primary brain tumors and patients with brain metastases.     

Overview of the role of liquid biopsy in cancer management

With the emergence of novel targeted therapeutic options in early-stage and advanced-stage malignancies, researchers have shifted their focus on developing personalized treatment plans through molecular profiling. Circulating tumor DNA (ctDNA) is a cell-free DNA (ctDNA) fragment, originating from tumor cells, and circulating in the bloodstream as well as biological fluids. Over the past decade, many techniques were developed for liquid biopsies through next-generation sequencing. This alternative non-invasive biopsy offers several advantages in various types of tumors over traditional tissue biopsy. The process of liquid biopsy is considered minimally invasive and therefore easily repeatable when needed, providing a more dynamic analysis of the tumor cells. Moreover, it has an advantage in patients with tumors that are not candidates for tissue sampling. Besides, it offers a deeper understanding of tumor burden as well as treatment response, thereby enhancing the detection of minimal residual disease and therapeutic guidance for personalized medicine. Despite its many advantages, ctDNA and liquid biopsy do have some limitations.This paper discusses the basis of ctDNA and the current data available on the subject, as well as its clinical utility. We also reflect on the limitations of using ctDNA in addition to its future perspectives in clinical oncology and precision medicine.     

Accuracy of cytologic diagnosis of central nervous system neoplasms in sterotactic biopsies

The cytohistologic correlation is reported for 112 of the 128 consecutive sterotactic aspiration biopsies performed on patients with clinical and neuroradiologic evidence of brain tumors investigated at the Neurosurgery Department, Karolinska Hospital, from 1976 to 1979. The cytodiagnostic accuracy of benign and malignant tumors was 87% when adequate cell material was obtained. In 17 benign tumors of the sellar region, the diagnostic rate was 88%; cytologic examination independent of histologic biopsy is feasible in this area. The cytodiagnostic accuracy for 95 malignant central nervous system (CNS) tumors was 87% after adjusting for the appreciable sampling error inherent in the use of a stereotactic procedure during the early phase of the study. Two histopathologically proven infectious lesions were reported cytologically as benign. The main microscopic problems were the recognition of highly differentiated astroglial neoplasms and the differential diagnosis between poorly differentiated brain neoplasms and metastases to the CNS. Cytodiagnostic accuracy of CNS tumors can be increased by technical improvements in the stereotactic device, diagnostic experience and immunochemical staining.     

Biopsy histopathology in herpes simplex encephalitis and in encephalitis of undefined etiology.

The histopathology of herpes simplex encephalitis (HSE) has been described principally from postmortem studies which reveal end-stage disease. Biopsy material, which selects an earlier stage in disease development, has been used principally to isolate virus, identify viral particles, and locate viral antigens. Further, little attention has been paid to the histopathology of biopsies of encephalitis of undefined etiology. In the present study, sections from biopsies which yielded virus and those which were negative for virus were evaluated in a systematic and controlled manner. Biopsies yielding virus were characterized by meningeal inflammation, perivascular infiltrates, and glial nodules. Biopsies which did not yield virus and which failed to reveal another diagnosis were characterized by nonspecific gliosis. Thus the early histiopathology of HSE is characterized by early signs of inflammation in the absence of necrosis and generally differs from biopsies in which virus is not isolated.     

Increased gastric expression of MMP-7 in hypergastrinemia and significance for epithelial-mesenchymal signaling

Chronic hypergastrinemia is associated with enterochromaffin-like (ECL) cell hyperplasia, which may progress to gastric carcinoid tumors. The latter consists of epithelial cells and stroma, and both compartments usually regress after normalization of hypergastrinemia. We previously showed that matrix metalloproteinase (MMP)-7 in gastric epithelial cells was upregulated by Helicobacter pylori and described MMP-7-dependent reciprocal signaling between the epithelium and a key stromal cell type, the myofibroblast. Here, we describe the regulation of gastric MMP-7 by gastrin and the potential significance for recruiting and maintaining myofibroblast populations. Biopsies of the gastric corpus and ECL cell carcinoid tumors were obtained from hypergastrinemic patients. Western blot analysis, ELISA, immunohistochemistry, and promoter-luciferase (luc) reporter assays were used to study MMP-7 expression. Gastric myofibroblasts were identified by alpha-smooth muscle actin (alpha-SMA) expression, and the effects of MMP-7 on myofibroblast proliferation were investigated. In hypergastrinemic patients, there was an increased abundance of MMP-7 and alpha-SMA in gastric corpus biopsies and ECL cell carcinoid tumors. In the latter, MMP-7 was localized to ECL cells but not stromal cells, which were nevertheless well represented. Gastrin stimulated MMP-7-luc expression in both AGS-G(R) and primary human gastric epithelial cells. Conditioned medium from gastrin-treated human gastric glands stimulated myofibroblast proliferation, which was inhibited by neutralizing antibodies to MMP-7. MMP-7 increased the proliferation of myofibroblasts via the MAPK and phosphatidylinositol 3-kinase (PI3K) pathways. In conclusion, stimulation of gastric MMP-7 by elevated plasma gastrin may activate epithelial-mesenchymal signaling pathways regulating myofibroblast function via MAPK and PI3K pathways and contribute to stromal deposition in ECL cell carcinoid tumors.