Costs and benefits of photosynthetic light acclimation by tree seedlings in response to gap formation.

Some shade leaves increase their photosynthetic capacity (P (max)) when exposed to a higher irradiance. The increase in P (max) is associated with an increase in chloroplast size or number. To accommodate those chloroplasts, plants need to make thick leaves in advance. We studied the cost and benefit of photosynthetic acclimation in mature leaves of a tree species, Kalopanax pictus Nakai, in a cool-temperate deciduous forest. Costs were evaluated as the additional investment in biomass required to make thick leaves, while the benefit was evaluated as an increase in photosynthetic carbon gain. We created gaps by felling canopy trees and examined the photosynthetic responses of mature leaves of the understorey seedlings. In the shade, leaves of K. pictus had vacant spaces that were not filled by chloroplasts in the mesophyll cells facing the intercellular space. When those leaves were exposed to higher irradiance after gap formation, the area of the mesophyll surface covered by chloroplasts increased by 17% and P (max) by 27%. This increase in P (max) led to an 11% increase in daily carbon gain, which was greater than the amount of biomass additionally invested to construct thicker leaves. We conclude that the capacity of a plant to acclimate to light (photosynthetic acclimation) would contribute to rapid growth in response to gap formation.

Generation of anti-tumour effector T cells from naïve T cells by stimulation with dendritic/tumour fusion cells.

Tumour-draining lymph node T cells are an excellent source of effector T cells that can be used in adoptive tumour immunotherapy because they have already been sensitized to tumour-associated antigens in vivo. However, such tumour-specific immune cells are not readily obtained from the host due to poor immunogenicity of tumours and reduced host immune responses. One obstacle in implementation of adoptive immunotherapy has been insufficient sensitization and expansion of tumour-specific effector cells. In this study, we aim to improve adoptive immunotherapy by generating anti-tumour effector T cells from naïve T lymphocytes. We attempted to achieve this by harnessing the advantages of dendritic cell (DC)-based anti-cancer vaccine strategies. Electrofusion was routinely employed to produce fusion cells with 30-40% efficiency by using the poorly immunogenic murine B16/F10 cell line, D5 cells, and DC generated from bone marrow cells. CD62L-positive T cells from spleens of naïve mice and the fusion cells were cocultured with a low concentration of IL-2. After 9 days of culture, the antigen-specific T cells were identified with an upregulation of CD25 and CD69 expression and a downregulation of CD62L expression. These cells secreted IFN-gamma upon stimulation with irradiated tumour cells. Moreover, when transferred into mice with 3-day established pulmonary metastases, these cells with coadministration of IL-2 exhibited anti-tumour efficacy. In contrast, naïve T cells cocultured with a mixture of unfused DC and irradiated tumour cells did not exhibit anti-tumour efficacy. Our strategy provides the basis for a new approach in adoptive T cell immunotherapy for cancer.

Leaf anatomy and light acclimation in woody seedlings after gap formation in a cool-temperate deciduous forest.

The photosynthetic light acclimation of fully expanded leaves of tree seedlings in response to gap formation was studied with respect to anatomical and photosynthetic characteristics in a natural cool-temperate deciduous forest. Eight woody species of different functional groups were used; two species each from mid-successional canopy species (Kalopanax pictus and Magnolia obovata), from late-successional canopy species (Quercus crispula and Acer mono), from sub-canopy species (Acer japonicum and Fraxinus lanuginosa) and from vine species (Schizophragma hydrangeoides and Hydrangea petiolaris). The light-saturated rate of photosynthesis (Pmax) increased significantly after gap formation in six species other than vine species. Shade leaves of K. pictus, M. obovata and Q. crispula had vacant spaces along cell walls in mesophyll cells, where chloroplasts were absent. The vacant space was filled after the gap formation by increased chloroplast volume, which in turn increased Pmax. In two Acer species, an increase in the area of mesophyll cells facing the intercellular space enabled the leaves to increase Pmax after maturation. The two vine species did not significantly change their anatomical traits. Although the response and the mechanism of acclimation to light improvement varied from species to species, the increase in the area of chloroplast surface facing the intercellular space per unit leaf area accounted for most of the increase in Pmax, demonstrating the importance of leaf anatomy in increasing Pmax.

Asymptomatic brain tumor detected at brain check-up.

Brain check-up was performed in 4000 healthy subjects who underwent medical and radiological examinations for possible brain diseases in our hospital from April 1996 to March 2000. Magnetic resonance imaging revealed 11 brain tumors which consisted of six meningiomas, three pituitary adenomas, one astrocytoma, and one epidermoid cyst. The detection rate of incidental brain tumor in our hospital was 0.3%. Nine patients underwent surgery, with one case of morbidity due to postoperative transient oculomotor nerve paresis. The widespread use of brain check-up may increasingly detect asymptomatic brain tumors. Surgical indications for such lesions remain unclear, and the strategy for treatment should be determined with consideration of the patient's wishes.

[Cerebral arteritis and cerebritis caused by subdural empyema: two cases report].

We report two cases of cerebral angitis and cerebritis caused by subdural empyema. A 22-year-old man, who complained of a headache and high fever, suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling. CT angiography showed diffuse narrowing of the left internal carotid artery, middle cerebral artery, and anterior cerebral artery. Although we performed craniotomy, continuous irrigation with drainage, systemic injection of antibiotics for subdural empyema, antiplatelet therapy, and hyperbaric oxygen therapy for angitis, his condition remained unchanged. A 67-year-old man who had previously undergone burr hole surgery presented to our hospital for the treatment of scalp infection. He suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling, but MR angiography did not show any abnormal findings. Hemiparesis improved after the surgery and systemic injection of the antibiotics. Subdural empyema with sinusitis or meningitis around the skull base sometimes causes cerebral angitis. We considered that the angiographical evaluation for the subdural empyema was necessary to detect angitis.

Infrared spectra of 1 -monopalmitin- or 1-monostearin-water systems in the gel phase.

The infrared spectra of 1-monopalmitin- or 1-monostearin-water systems in the gel phase were observed at room temperature. In both systems the infrared intensities of the bands parallel and perpendicular to the paraffin chain are relatively reduced and enhanced, respectively, on going from the crystalline phase to the gel phase. These spectral changes are explained in terms of the interaction among oscillating dipoles, which is sensitive to the morphology change from the three-dimensional crystalline phase to the two-dimensional lipid bilayers. The non-planar lipid bilayers are proposed for the gel phase in monopalmitin-water systems with x > or = 35 (x: wt.% water).

The role of a mitochondrial pathway in the induction of apoptosis by chemicals extracted from diesel exhaust particles.

We are interested in the cytotoxic and proinflammatory effects of particulate pollutants in the respiratory tract. We demonstrate that methanol extracts made from diesel exhaust particles (DEP) induce apoptosis and reactive oxygen species (ROS) in pulmonary alveolar macrophages and RAW 264.7 cells. The toxicity of these organic extracts mimics the cytotoxicity of the intact particles and could be suppressed by the synthetic sulfhydryl compounds, N-acetylcysteine and bucillamine. Because DEP-induced apoptosis follows cytochrome c release, we studied the effect of DEP chemicals on mitochondrially regulated death mechanisms. Crude DEP extracts induced ROS production and perturbed mitochondrial function before and at the onset of apoptosis. This mitochondrial perturbation follows an orderly sequence of events, which commence with a change in mitochondrial membrane potential, followed by cytochrome c release, development of membrane asymmetry (annexin V staining), and propidium iodide uptake. Structural damage to the mitochondrial inner membrane, evidenced by a decrease in cardiolipin mass, leads to O-*2 generation and uncoupling of oxidative phosphorylation (decreased intracellular ATP levels). N-acetylcysteine reversed these mitochondrial effects and ROS production. Overexpression of the mitochondrial apoptosis regulator, Bcl-2, delayed but did not suppress apoptosis. Taken together, these results suggest that DEP chemicals induce apoptosis in macrophages via a toxic effect on mitochondria.

Chemicals in diesel exhaust particles generate reactive oxygen radicals and induce apoptosis in macrophages.

There is increasing evidence that particulate air pollutants, such as diesel exhaust particles (DEP), potentiate chronic inflammatory processes as well as acute symptomatic responses in the respiratory tract. The mechanisms of action as well as the cellular targets for DEP remain to be elucidated. We show in this paper that the phagocytosis of DEP by primary alveolar macrophages or macrophage cell lines, RAW 264.7 and THP-1, leads to the induction of apoptosis through generation of reactive oxygen radicals (ROR). This oxidative stress initiates two caspase cascades and a series of cellular events, including loss of surface membrane asymmetry and DNA damage. The apoptotic effect on macrophages is cell specific, because DEP did not induce similar effects in nonphagocytic cells. DEP that had their organic constituents extracted were no longer able to induce apoptosis or generate ROR. The organic extracts were, however, able to induce apoptosis. DEP chemicals also induced the activation of stress-activated protein kinases, which play a role in cellular apoptotic pathways. The injurious effects of native particles or DEP extracts on macrophages could be reversed by the antioxidant, N-acetyl-cysteine. Taken together, these data suggest that organic compounds contained in DEP may exert acute toxic effects via the generation of ROR in macrophages.

Effects of clotrimazole on the growth, morphological characteristics, and cisplatin sensitivity of human glioblastoma cells in vitro.

OBJECT: Clotrimazole, an antimycotic drug, inhibits proliferation of normal and cancer cells by downregulating the movement of intracellular Ca++ and K+. The authors examined the effect of clotrimazole on the growth and sensitivity to cisplatin of two human glioblastoma cell lines--A172, which has the wild-type p53 gene, and T98G, which has the mutant p53 gene in vitro. METHODS: The A172 and T98G glioblastoma cells were exposed to clotrimazole and cell growth was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium chloride colorimetric assay. Clotrimazole produced a dose-dependent inhibition of cell proliferation and caused changes in cellular structure toward a well-differentiated form. The growth inhibitory effect of clotrimazole was reversible. Western immunoblot analysis revealed a marked increase in cellular glial fibrillary acidic protein and wild-type p53 and a decrease in c-myc and c-fos oncoproteins in both cell lines treated with clotrimazole. Flow cytometric analysis revealed that clotrimazole-treated cells accumulated in the G0/G1 phase with a marked decrease in cells in the S phase; when clotrimazole was washed out from the culture medium, cells again started to proliferate, with a marked decrease in cells in the G0/G1 phase and an increase in cells in the S phase. The growth inhibitory effect of clotrimazole could not be overcome by exogenous stimulation with either epidermal growth factor or c-myc peptide. A combined treatment with clotrimazole and cisplatin significantly enhanced cell cytotoxicity compared with treatment using either drug alone. A DNA fragmentation assay showed that both clotrimazole and cisplatin induced apoptosis, which was increased in cells treated by both drugs. CONCLUSIONS: The present study indicates that clotrimazole inhibits cell proliferation accompanied by morphological changes toward differentiation of glioblastoma cells and that this drug synergistically enhances the antitumor effect of cisplatin by inducing wild-type p53-mediated apoptosis.

Fruit set in Styrax obassia (Styracaceae): the effect of light availability, display size, and local floral density.

Maternal reproductive success was examined in Styrax obassia (Styracaceae), a bumble-bee pollinated mass-flowering tree in a cool-temperate deciduous forest in northern Japan. The effects of flower number on the success of individual flowers at three levels (inflorescence, individual, and population) were considered. During 1995 and 1996, variations in size, light availability to branches, floral display size, and fruit set were monitored in 37 out of 211 individual S. obassia trees in a 4-ha forest plot. In addition, the locations of the 211 trees in this plot were mapped and the number of inflorescences in each tree was counted. A multiple regression analysis showed that flower number per inflorescence and inflorescence number per individual had negative effects on fruit set, and inflorescence number of aggregated clumps of flowering trees, tree size, and light resource had positive effects on fruit set although significant level were marginal. It is concluded that pollinator attraction may occur not at the individual tree level, but at the level of a clump of flowering trees. It is also suggested that geitonogamy increased with inflorescence number of tree and inflorescence size and that resource limitation was related to the light condition and variation of tree size.

The Jun kinase cascade is responsible for activating the CD28 response element of the IL-2 promoter: proof of cross-talk with the I kappa B kinase cascade.

Costimulation of TCR/CD3 and CD28 receptors leads to activation of the Jun kinase (JNK) cascade, which plays a key role in T cell activation, including activation of the IL-2 promoter. We demonstrate that the JNK cascade plays a central role in the activation of the CD28 response element (CD28RE) in the IL-2 promoter. This response element is linked to an activating protein-1 (AP-1) site, which functions synergistically with the CD28RE. The role of the JNK cascade in the activation of this composite element is twofold: 1) activation of the AP-1 site through transcriptional activation of c-Jun, and 2) activation of the CD28RE through selective cross-talk with I kappa B kinase-beta (IKK beta). Dominant-negative versions of JNK kinase, c-Jun, and IKK beta interfered In CD3- plus CD28-induced CD28RE/AP-1 luciferase activity in Jurkat cells. In contrast, the dominant-active JNK kinase kinase, MEKK1, induced CD28RE/AP-1 luciferase activity, in parallel with induction of c-Jun and c-Rel binding to this combined promoter site. Dominant-active MEKK1 also induced transfected IKK beta, but not IKK alpha, activity. In contrast to the JNK cascade, the extracellular signal-regulated kinase (ERK) cascade did not exert an affect on the CD28RE/AP-1 site, but did contribute to activation of the distal NF-AT/AP-1 site.

Activation of the human RANTES gene promoter in a macrophage cell line by lipopolysaccharide is dependent on stress-activated protein kinases and the IkappaB kinase cascade: implications for exacerbation of allergic inflammation by environmental pollutants.

Macrophages are targeted by environmental pollutants and play a role in allergic inflammation. We explored the molecular basis for induction of RANTES (regulated upon activation, normal T-cells expressed and secreted) mRNA by lipopolysaccharide (LPS) and the redox-active quinone, tert-butylhydroxyquinone (tBHQ). We demonstrate that transcriptional activation of the human RANTES promoter by LPS is dependent on specific AP-1 and NF-kappaB response elements, which are regulated by c-Jun N-terminal kinase (JNK) and NF-kappaB kinase cascades, respectively. The transcriptional activation of the TRE3/4 site is mediated through the transcriptional activation of c-Jun by JNK. A c-Jun mutant which lacks a transcriptional activation domain interfered in the activation of the RANTES promoter. Similarly, kinase-inactive NF-kappaB inducing kinase interfered in the activation of the RANTES promoter. While activation of the RANTES promoter could also be blocked by the downstream kinase-inactive IkappaB kinases, only IKKalpha appears to be LPS-inducible. tBHQ also exerted subtle effects on the human RANTES promoter and induced mRNA expression in parallel with generating NF-kappaB shift complexes.

Enhancement of allergic inflammation by diesel exhaust particles: permissive role of reactive oxygen species.

BACKGROUND: Diesel emission particulates (DEP) exert effects on the immune system and act as an adjuvant which enhances allergic inflammation. Animal and human models have delineated the effects of DEP chemicals in enhancing IgE production and promoting T-helper cell-2 (Th2) differentiation. An important primary effect that can explain the DEP-associated humoral and cellular immune responses is the induction of macrophage responses by DEP chemicals. This includes effects on macrophage production of cytokines and chemokines, which may play a role in enhancing allergic inflammation. A potent mechanism in macrophages exposed to DEP chemicals involves the generation of reactive oxygen species (ROS), leading to cellular activation or apoptosis which can be abrogated by antioxidants. CONCLUSION: These findings may establish a role for antioxidant therapy in diminishing the effects of particulate pollutants in asthma.

Immunohistochemical analysis of metallothionein in astrocytic tumors in relation to tumor grade, proliferative potential, and survival.

BACKGROUND: Metallothionein (MT) is the name for a family of predominantly intracellular protein thiol compounds involved in anticancer drug resistance. For certain tumors, MT is related to grade of tumor malignancy and prognosis. The authors evaluated the expression of MT in 114 astrocytic tumors in relation to the proliferative potential of tumors and the survival of patients. METHODS: Paraffin embedded tissue sections were stained with monoclonal anti-metallothionein and MIB-1 Ki-67 antibodies by avidin-biotin complex immunohistochemistry. RESULTS: MT expression was observed in 2 of 6 pilocytic astrocytomas, in 10 of 24 Grade 2 astrocytomas, in 16 of 25 anaplastic astrocytomas, and in 47 of 59 glioblastomas. In addition to the tumor cells, microvascular endothelial proliferation and smooth muscle of tumor vessel walls were frequently MT positive. The glioblastomas had a significantly higher percentage of MT positive cells compared with low grade (P < 0.0001) and anaplastic (P < 0.04) astrocytomas. MT expression in astrocytomas had no correlation with tumor recurrence. The mean Ki-67 labeling index (LI) was significantly higher in the high grade (3-4) compared with the low grade (1-2) astrocytomas. MT positive astrocytic tumors had statistically significantly higher mean Ki-67 LI compared with MT negative tumors, irrespective of histologic grade. Although the levels of MT and Ki-67 LI varied in individual tumors, the mean Ki-67 LI increased in parallel to the increasing MT staining grade, and this difference attained statistical significance only for glioblastoma. MT positive anaplastic astrocytoma and glioblastoma patients did not survive as long as the MT negative patients, although this difference attained statistical significance only for anaplastic astrocytoma. CONCLUSIONS: The current study suggests that MT might play a significant role in the growth of astrocytic tumors, with an acquired enhanced ability to produce MT as the malignant potential of a tumor increases.

Enhancement of allergic inflammation by the interaction between diesel exhaust particles and the immune system.

There is growing evidence that fossil fuel combustion products act as adjuvants in the immune system and may lead to enhancement of allergic inflammation. Through this mechanism, particulate air pollutants may be an important contributor to the increased prevalence and morbidity of asthma and allergic rhinitis. In this communication we focus on the role of diesel exhaust particles (DEPs) in skewing the immune response towards IgE production and induction of allergic inflammation. We review experimental studies in animals and humans showing that DEPs enhance IgE production by a variety of mechanisms, including effects on cytokine and chemokine production, as well as activation of macrophages and other mucosal cell types. We discuss metabolic and cellular activation pathways linked to chemicals such as polycyclic aromatic hydrocarbons contained in DEPs and demonstrate how these molecular events may impact cytokine, chemokine, and accessory molecule expression in the immune system.

Macrophage activation by polycyclic aromatic hydrocarbons: evidence for the involvement of stress-activated protein kinases, activator protein-1, and antioxidant response elements.

Polycyclic aromatic hydrocarbons (PAH) contained in fossil fuel combustion particles enhance the allergic response to common environmental Ags. A key question is: what are molecular pathways in the immune system by which PAH and conversion products drive allergic inflammation? Circumstantial evidence suggests that macrophages are involved in PAH-induced responses. We demonstrate that a representative PAH, beta-napthoflavone (BNF), and a representative quinone metabolite, tert-butylhydroxyquinone (tBHQ), induce Jun kinase and p38 mitogen-activated protein kinase activities in parallel with the generation of activator protein-1 (AP-1) mobility shift complexes in THP-1 and RAW264.7 macrophage cell lines. Activation of mitogen-activated protein kinases was dependent on generation of oxidative stress, and could be inhibited by N-acetylcysteine. Another genetic response pathway linked to PAH is the antioxidant response element (ARE), which regulates expression of detoxifying enzymes. BNF and tBHQ activated a human ARE (hARE) reporter gene in RAW264.7 cells. Interestingly, bacterial lipopolysaccharide also induced hARE/chloramphenicol acetyltransferase activity. While the hARE core, GTGACTCAGC, contains a consensus AP-1 sequence (underlined), AP-1 was not required for hARE activation. This suggests that PAH and their conversion products operate via ARE-specific transcription factors in the immune system. BNF and tBHQ did, however, induce AP-1 binding to the hARE, while constitutively active Jun kinase interfered in hARE/chloramphenicol acetyltransferase activation. This suggests that AP-1 proteins negatively regulate the hARE. These data establish important activation pathways for PAH in the immune system and provide us with targets to modulate the effect of environmental pollutants on allergic inflammation.

NF-kappaB-mediated inhibition of apoptosis is required for encephalomyocarditis virus virulence: a mechanism of resistance in p50 knockout mice.

Apoptosis is a central host defense mechanism to eliminate virus-infected cells. Activation of NF-kappaB suppresses apoptosis following some types of stimulation in vitro. To test the physiological importance of this pathway in vivo, we studied murine encephalomyocarditis virus (EMCV) infection in mice and cell lines defective in NF-kappaB1 (p50) signaling. As previously reported, we find that all p50 knockout (p50 -/-) mice survive an EMCV infection that readily kills normal mice. By introducing the p50 mutation into interferon (IFN) type I receptor knockout (IFNRI -/-) mice, we find that this resistance is not mediated by IFN-beta as previously thought. While no IFNRI -/- mice survive, the double-knockout mice survive 60% of the time. The survival is tightly linked to the animals' ability to clear the virus from the heart in vivo. Using murine embryonic fibroblasts (MEF) derived from wild-type, p50 -/-, and p65 -/- embryos, we found that NF-kappaB is not required for the replication cycle of EMCV. However, during these experiments we observed that p50 -/- and p65 -/- MEF infected with EMCV undergo enhanced, premature cytotoxicity. Upon examination of this cell death, we found that EMCV infection induced both plasma membrane and nuclear changes typical of apoptosis in all cell lines. These apoptotic processes occurred in an accelerated and pronounced way in the NF-kappaB-defective cells, as soon as 6 h after infection, when virus is beginning to be released. Previously, only the RelA (p65) subunit of NF-kappaB has been shown to play a role in suppressing apoptosis. In our studies, we find that p50 is equally important in suppressing apoptosis during EMCV infection. Additionally, we show that suppression of apoptosis by NF-kappaB1 is required for EMCV virulence in vivo. The attenuation in p50 -/- mice can be explained by rapid apoptosis of infected cells which allows host phagocytes to clear infected cells before the viral burst leading to a reduction of the viral burden and survival of the mice.

Immunohistochemical analysis of p53 and p21 in human primary glioblastomas in relation to proliferative potential and apoptosis.

The Cdk inhibitor p21/WAF1 can be transcriptionally activated by wild-type p53, not by mutant p53, and functions to block cell-cycle progression in many human neoplasms. We examined the immunohistochemical expression of p53 and p21 in 35 human primary glioblastomas in relation to tumor proliferation potential as assessed by the Ki-67 labeling index (LI) and the glioblastoma apoptosis index (AI). The expression of mutant p53 was observed in 74% of glioblastomas, wild-type p53 in 18% of glioblastomas, and p21 in 57% of glioblastomas. p21 expression was seen in 15 of 26 mutant p53-positive and 2 of 4 wild p53-positive tumors. Tumor Ki-67 LI correlated neither with p53 nor with p21 expression in glioblastomas. Apoptosis was identified in all 15 glioblastomas examined, with a mean (+/-SD) Al of 1.69+/-1.54, and correlated neither with p53 (wild or mutant) nor with p21 expression. The results of the present study suggest that p53 mutation and p21 protein expression are frequent in primary glioblastoma but lack correlation with tumor proliferation potential and apoptosis. The lack of correlation between p21 and p53 also suggests that p21 in glioblastomas may be induced by a p53-independent pathway.

Immunohistochemical analysis of progesterone receptor and Ki-67 labeling index in astrocytic tumors.

BACKGROUND: Intracranial tumors such as meningiomas express steroid hormone receptors but little is known regarding progesterone receptor (PR) in astrocytic tumors. The authors evaluated expression of PR in 86 astrocytic tumors in relation to tumor proliferative potential. METHODS: Paraffin embedded tumor sections were stained with polyclonal antiprogesterone antibody by the peroxidase-antiperoxidase method and with monoclonal MIB-1-Ki-67 antibody by avidin-biotin complex immunohistochemistry. RESULTS: Sixty-three of the 86 astrocytic tumors (73%) showed positive PR immunoreactivity. PR expression was observed in 4 of 9 pilocytic astrocytomas, 13 of 24 Grade 2 astrocytomas, 15 of 20 anaplastic astrocytomas, and 31 of 33 glioblastomas. In addition to the tumor cells, cells of microvascular endothelial proliferation and the smooth muscle of tumor vessel walls were frequently PR positive. Glioblastomas had a significantly higher percentage of PR positive cells compared with anaplastic (P < 0.0008) and low grade (P < 0.0001) astrocytomas. Patients with PR positive astrocytomas were of an older age than patients with PR negative astrocytomas (48.71 +/- 21.95 years vs. 37.09 +/- 24.69 years; P < 0.04). The mean Ki-67 labeling index (LI) was significantly higher in the high grade (3-4) astrocytomas compared with low grade (1-2) astrocytomas (P < 0.0001). PR positive astrocytic tumors had higher Ki-67 LI than PR negative tumors. PR expression was not correlated with tumor recurrence and patient survival. CONCLUSIONS: The current study suggests that PR in the astrocytic tumors correlates with histologic grade and PR may participate in the growth of these tumors and tumor angiogenesis. The measurement of PR in these tumors may indirectly represent tumor growth potential.

Minigemistocytic astrocytoma with frequent apoptoses: analysis of tumor growth.

A rare glial tumor known as 'minigemistocytic astrocytoma (gliofibrillary oligodendroglioma)' is reported in a 73 year old Japanese male. A low-density area found by computed tomography and thought to be an operative scare remaining after hematoma in the right frontal lobe of the cerebrum had been followed for 10 years. This area, however, had been accompanied by a cyst for 2 years and had developed gradually for 1 year prior to dissection. The tumor was poorly demarcated from the surrounding normal tissue macroscopically at operation. Microscopically, the tumor consisted of small gemistocytic cells in uniform sheets intersected by a small vascular stroma with frequent eosinophilic granular bodies, mitoses and apoptotic bodies. Immunohistochemical examination for glial fibrillary acidic protein (GFAP) revealed remarkable positive reactivity in the perinuclear cytoplasm, but no immunoreactivity for vimentin or Leu 7 was found. Electron microscopically, rich filaments arranged in parallel bundles were found in the neoplastic cells. These histological findings are closely consistent with those of previously reported minigemistocytic astrocytoma cases. The GFAP-rich minigemistocytic astrocytoma with granular bodies and frequent mitoses in the present case is considered to indicate a higher degree of astrocytic differentiation and malignant potential than previous cases. The frequent apoptoses, however, might inhibit tumor growth in this case.