gp120, a human immunodeficiency virus-1 coat protein, augments excitotoxic hippocampal injury in perinatal rats

Recent data suggest that gp120, a human immunodeficiency virus-1 (HIV-1) coat glycoprotein that is secreted by HIV-infected cells, is neurotoxic, and that this toxicity is mediated, at least in part, by activation of N-methyl-D-aspartate-type excitatory amino acid receptors. To test this hypothesis in vivo, we examined the neurotoxicity of gp120 injected intrahippocampally, alone or co-injected with the selective excitatory amino acid agonist N-methyl-D-aspartate, in seven-day-old rats. Severity of injury in the lesioned hippocampus was assessed five days later, using three outcome measures: histopathology, hippocampal atrophy (derived from regional cross-sectional area measurements) and loss of [3H]glutamate receptor binding (based on in vitro autoradiography assays). To confirm that any observed effects were attributable to gp120 bioactivity, each group of experiments included controls that received equal amounts of heat-treated gp120. Gp120 (200 ng) elicited minimal focal pyramidal cell loss immediately adjacent to the injection track; there was no hippocampal atrophy or loss of [3H]glutamate binding. Co-injection of 50 ng gp120 with N-methyl-D-aspartate (5 nmol, threshold excitotoxic dose) increased the severity of hippocampal injury; hippocampal atrophy was greater in animals that received injections of 5 nmol N-methyl-D-aspartate in combination with 50 ng gp120 than in those that received either N-methyl-D-aspartate alone (5 nmol) or 5 nmol N-methyl-D-aspartate+50 ng heat-treated gp120 (mean+/-S.E.M. percentage reduction in injected hippocampal volume vs contralateral: N-methyl-D-aspartate, -19+/-3; N-methyl-D-aspartate+gp120, -26.8+/-2.1; N-methyl-D-aspartate+heat-treated gp120, -14.0+/-2.2; P<0.001, ANOVA). Treatment with the competitive N-methyl-D-aspartate antagonist 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (20mg/kg) markedly reduced the severity of injury elicited by the combination of gp120 with N-methyl-D-aspartate. These data support the hypothesis that locally secreted gp120 could exert neurotoxic effects, mediated by N-methyl-D-aspartate receptor activation, in vivo in the immature brain.

Effects of chronic treatment with a cyclic AMP-selective phosphodiesterase inhibitor, rolipram, on excitatory amino acid neurotransmission systems in young and aged rat brains

Rolipram selectively inhibits cyclic AMP-specific phosphodiesterase, and leads to an increase in cyclic AMP levels in the brain. In this study, we investigated the effects of chronic rolipram treatment on excitatory and inhibitory amino acid neurotransmission systems in young and aged Wistar rat brains. We used in vitro autoradiography with [3H]MK-801, [3H]glycine, D[3H]aspartate, and [3H]muscimol to label N-methyl-D-aspartate (NMDA) receptors, glycine modulatory sites, glutamate transport sites, and gamma-aminobutyric acid-A (GABA) receptors, respectively. Rolipram (0.01 or 0.1 mg/kg, per os) or its vehicle (distilled water) was administered once a day for 4 weeks. The highest binding of [3H]MK-801, [3H]glycine, and D-[3H]aspartate was seen in the hippocampus in vehicle-treated rats. No significant differences in these binding activities were seen between young and aged rat brains. [3H]Muscimol binding was the highest in the cerebellum, and decreased in many brain regions in aged rats. The chronic rolipram treatment resulted in (1) an increase in [3H]MK-801 binding in the dentate gyrus in both young and aged rats, (2) remarkable reductions in D-[3H]aspartate binding in many regions of both young and aged rats, and (3) no or minimal changes in [3H]glycine and [3H]muscimol binding. These results suggest that the chronic rolipram treatment modifies the excitatory amino acid neurotransmission system.

Effect of age, ethnicity, and head injury on the association between APOE genotypes and Alzheimer's disease

The association between apolipoprotein E (APOE)-epsilon 4 and Alzheimer's disease has been confirmed worldwide. We and others have observed a diminished association in the very old and among African-Americans compared to Caucasians and Hispanics in New York. In this review we describe a new method we developed to compare relative risks by APOE genotypes in an expanded cohort of cases and controls from three ethnic groups in a New York City community and discuss the association as between APOE epsilon 4 and Alzheimer's disease as modified by head injury. Compared to persons with APOE epsilon 3/epsilon 3 genotypes, relative risk (RR) for Alzheimer's disease associated with APOE epsilon 4 homozygosity was similar across ethnic groups (African-American RR = 3.3; 95% c.i. 1.6-6.8; Caucasian RR = 5.3; 1.6-16.0; Hispanic RR = 2.5; 1.1-5.8). The risk was also increased for APOE epsilon 4 heterozygous Caucasians (RR = 3.2; 1.8-5.8) and Hispanics (RR 1.5; 1.0-2.2) but not African-Americans (RR = 0.6; 0.4-0.9). Risk of AD was not significantly diminished for individuals in any group with APOE epsilon 2/epsilon 2 or -epsilon 2/epsilon 3 genotypes. A 10-fold increase in the risk of Alzheimer's disease was associated with both APOE epsilon 4 and a history of traumatic head injury, compared to a twofold increase in risk with APOE epsilon 4 alone. Head injury in the absence of an APOE epsilon 4 allele did not increase risk. These results imply that in Alzheimer's disease genotypic risk associated with APOE may be influenced by age, ethnicity, and certain environmental factors.

The 12-lipoxygenase gene-transfected MCF-7 human breast cancer cell line exhibits estrogen-independent, but estrogen and omega-6 fatty acid-stimulated proliferation in vitro, and enhanced growth in athymic nude mice

The estrogen-dependent, linoleic acid (LA)-unresponsive, MCF-7 breast cancer cell line was transfected with 12-lipoxygenase (12-LOX) cDNA (MCF-7/12-LOX cells). The transfectant stably expressed high levels of 12-LOX mRNA and protein, and secreted large quantities of 12-hydroxyeicosatetraenoic acid when cultured with arachidonate. The transfectant grew in vitro in the absence of estrogen, and its growth was stimulated by LA. The MCF-7/12-LOX cells formed small solid tumors when injected into the mammary fat pads of ovariectomized nude mice. Despite this estrogen independence, MCF-7/12-LOX cell growth was stimulated further by estradiol both in vitro and in vivo, and to a greater extent than parental MCF-7 cells.

The platelet-activating factor antagonist BN 52021 attenuates hypoxic-ischemic brain injury in the immature rat

Platelet-activating factor (PAF) is overproduced in ischemic brain. Although postischemic PAF antagonist administration protects the mature brain in some models, little is known about the effects of PAF antagonists in the immature brain. We hypothesized that the PAF antagonist BN 52021 would attenuate perinatal cerebral hypoxic-ischemic injury. To elicit focal hypoxic-ischemic brain injury, 7-d-old (P7) rats (n = 111) underwent right carotid ligation, followed by 2.5-3.25 h of hypoxia (fractional concentration of inspired O2 = 0.08). BN 52021 neuroprotection was evaluated in three groups of experiments: 1) 25 mg/kg/dose, 0 and 2 h posthypoxia; 2), 25 mg/kg/dose immediately before and 1 h after hypoxia; and 3) posthypoxia-ischemia treatment with BN 52021 12.5, 25, or 50 mg/kg/dose in 2 doses 0 and 2 h after hypoxia. All experiments included concurrent vehicle-injected controls. To quantitate severity of injury, bilateral regional cross-sectional areas (groups 1 and 2) or hemisphere weights (group 3) were evaluated on P12. Both pre- and posthypoxic treatment with BN 52021 (25 mg/kg/dose, two serial doses) decreased the incidence of cerebral infarction from 90% to about 30% (p < 0.02, Fisher's exact test). Measurement of cross-sectional areas confirmed neuroprotection and indicated some benefit of pre- over posthypoxic-ischemic treatment in hippocampus and cortex. Over the dose range tested, the neuroprotective effect of BN 52021 administration was not dose-dependent. In contrast, BN 52021 did not attenuate N-methyl-D-aspartate-induced hippocampal excitotoxic injury in P7 rats. Either prophylactic or "rescue" administration of PAF antagonists decreases the incidence and severity of brain injury associated with an episode of perinatal cerebral hypoxia-ischemia.

Differential expression and regulation of cyclooxygenase-1 and -2 in two human breast cancer cell lines

Cyclooxygenase (COX), also referred to as prostaglandin endoperoxide synthase, is the rate-limiting enzyme for the metabolic conversion of arachidonic acid to prostaglandins (PGs) and related eicosanoids. Some human breast cancers synthesize large quantities of PGE2, but the regulatory mechanisms involved are unclear. We have examined the expression of the two isoforms of this enzyme, COX-1 and COX-2, their regulation by tetradecanoyl phorbol acetate (TPA), and the associated PGE2 production in two human breast cancer cell lines with different biological phenotypes. Estrogen-dependent MCF-7 cells exhibited a relatively high expression of COX-1; COX-2 was barely detectable but was transiently induced by treatment with TPA (10 nM). In contrast, the estrogen-independent, highly invasive, metastatic MDA-MB-231 cell line showed a low expression of COX-1 but a high constitutive level of COX-2. This high COX-2 expression applied to both the protein and mRNA and increased further over a relatively long period of time in the presence of TPA. The extent of PGE2 production by the two cell lines correlated well with the level of COX-2 protein, suggesting that this isoform is required for both their constitutive and mitogen-induced PGE2 synthesis. Moreover, overexpression and persistent expression of COX-2 may be influenced by breast tumor hormone status and seem to be a feature of the aggressive, metastatic phenotype.

Progressive expression of immunomolecules on activated microglia and invading leukocytes following focal cerebral ischemia in the rat

In order to evaluate the involvement of inflammatory reactions following focal cerebral ischemia in the rat, we immunohistochemically visualized microglial cells and blood-borne leukocytes (neutrophils and monocytes) using various antibodies directed against immunomolecules expressed on these cells. Focal cerebral ischemia was produced by intraluminal occlusion of the right middle cerebral artery for 1 h. The brains were perfusion-fixed at 4 h, 1 day, 3 days, 7 days and 14 days after ischemia. Frozen brain sections were prepared and stained with monoclonal antibodies to complement receptor type 3 (OX42), major histocompatibility complex (MHC) class I and class II antigens (OX18 and OX6, respectively), a pan-macrophage/monocyte marker (ED1), intercellular adhesion molecule-1 (ICAM-1), LFA-1 alpha chain (CD11a) and beta chain (CD18), and T cells (CD5). In ischemic areas where infarction developed later, microglial cells were destroyed (beginning at 4 h), neutrophils migrated (1-3 days), and then monocytes/macrophages infiltrated and covered the entire lesions (3-14 days). The invading leukocytes expressed CD11 and CD18 adhesion molecules on their cell surface while ICAM-1 was expressed on endothelial cells. In surrounding areas, in contrast, there was a rapid activation of microglia showing morphological changes and upregulation of OX42 immunoreactivity (4 h-7 days), especially in the transitional rim of the infarct (7 days). ED1 and MHC antigens were expressed on both activated microglia and invading leukocytes. Thus, developing infarction was accompanied by accumulation of inflammatory cells of both intrinsic (microglia) and extrinsic (leukocytes) origins. Thus, results suggest that the relative importance of each source is determined by the time after ischemia and the site within the lesion, and that the expression of immunological molecules plays an important role in eliciting such inflammatory reactions.

An orally active ETA/ETB receptor antagonist ameliorates proteinuria and glomerular lesions in rats with proliferative nephritis

The proliferation of mesangial cells and the extracellular matrix expansion constitute the most outstanding morphological aspects of the majority of progressive glomerular diseases. In vitro, endothelin-1 (ET-1) is mitogenic for mesangial cells and induces matrix protein synthesis. We studied the possible participation of ET-1 in the pathogenesis of renal damage in a normotensive model of proliferative nephritis. Coincidentally with maximal proteinuria and glomerular lesions, an increase was found in the glomerular mRNA expression of preproET-1 and the ETA receptor (10 and 6 times compared to controls, respectively), but not of the ETB receptor, and in ET-1 urinary excretion (217 +/- 33 vs. 84 +/- 4 pg ET-1/24 hr, N = 4 to 5, P < 0.05). By in situ hybridization, an increase in preproET-1 mRNA expression in glomerular endothelial, epithelial and mesangial cells, and in come tubular cells was observed. The administration of bosentan, an ETA/ETB receptor antagonist, had a beneficial effect on the evolution of nephritis preventing the appearance of intense proteinuria (76 +/- 35 vs. 380 +/- 77 mg/24 hr, N = 4 to 5, P < 0.05), the morphological lesions and the renal function impairment (creatinine clearance 367 +/- 46 vs. 268 +/- 33 microliters/min/100 g, N = 4 to 5). Simultaneously, there was a decrease in ET-1 urinary excretion (88 +/- 14 vs. 217 +/- 33 pgET-1/24 hr, N = 4,5, P < 0.05) and in the renal preproET-1 mRNA expression. The mean systolic blood pressures remained in the normal range in all animals. These data indicate that ET-1 participates in the pathogenesis of proteinuria and glomerular injury in a model of proliferative nephritis. The nonpeptidic orally active ETA/ETB receptor antagonists could be useful in the treatment of some human nephritis.

[Endothelin-stimulated proliferation of thoracic artery smooth muscle cells involves activation of mitogen-activated protein kinase]

Endothelin (ET) is a potent vasoconstrictor whose responses are mediated through a common G-protein coupled receptor. So far little is known concerning its potential mitogenic capacity. In the present study, experiments were conducted to determine the role of mitogen-activated protein kinase (MAPK) activation in the rabbit thoracic artery smooth muscle cells (VSMC) in response to stimulation by ET-1. It was found that ET-1 produced concentration- and time-dependent increases in 3H-TdR incorporation and in MAPK activity of these cells. All the increases were inhibited by protein kinase C (PKC) inhibitors, such as Staurosporine (STP) and H-7 and by ETA receptor antagonist BQ123, but not by specific tyrosine kinase inhibitor Herbimycin A (Herb). Pre-treatment with PKC activator PMA (phorbol myristate acetate) for 24 h (PKC downregulation) significantly attenuated ET-1-induced MAPK activation. These results indicate that: (1) ET-1-stimulated proliferation of VSMC involves the activation of MAPK and (2) ET-1-induced MAPK activation is mediated through ETA receptor and PKC.

Protection of retinal ganglion cells from natural and axotomy-induced cell death in neonatal transgenic mice overexpressing bcl-2

Approximately half of the retinal ganglion cells (RGCs) present in the rodent retina at birth normally die during early development. Overexpression of the photo-oncogene bcl-2 recently has been shown to rescue some neuronal populations from natural cell death and from degeneration induced by axotomy of nerves within the peripheral nervous system. Here we study in vivo the role of the overexpression of bcl-2 in the natural cell death of RGCs and in the degenerative process induced in these cells by transection of the optic nerve. We find that in newborn bcl-2 transgenic mice, the number of RGCs undergoing natural cell death is considerably lower than in wild-type pups. Consistently, a vast majority (90%) of the ganglion cells found in the retina of neonatal transgenics are maintained in adulthood, whereas only 40% survive in wild-type mice. After transection of the optic nerve, the number of degenerating ganglion cells, determined by counting pyknotic nuclei or nuclei with fragmented DNA, is substantially reduced in transgenic mice. In wild-type animals, almost 50% of ganglion cells degenerate in the 24 hr after the lesion, whereas almost the entire ganglion cell population survives axotomy in transgenic mice. Therefore, overexpression of bcl-2 is effective in preventing degeneration of this neuronal population, raising the possibility that ganglion cells are dependent on the endogenous expression of bcl-2 for survival. The remarkable rescue capacity of bcl-2 overexpression in these neurons makes it an interesting model for studying natural cell death and responses to injury in the CNS.

Eicosanoids as mediators of linoleic acid-stimulated invasion and type IV collagenase production by a metastatic human breast cancer cell line

Diets rich in linoleic acid (LA) stimulate the metastasis of MDA-MB-435 human breast cancer cells from the mammary fat pads of nude mice. This omega-6 fatty acid is metabolized to various cyclo-oxygenase and lipoxygenase products, several of which have been previously associated with tumor cell invasion and metastasis. We now report that MDA-MB-435 cells secreted increased levels of prostaglandin E2 (PGE2), and 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-HETE when cultured in the presence of 2.7 microM (0.75 micrograms/ml) LA; 5-HETE secretion was unchanged. The 12-lipoxygenase inhibitor esculetin (20 microM) completely blocked the LA-stimulated 12-HETE secretion. Linoleic acid also increased MDA-MB-435 cell invasion in an in vitro assay; this stimulation was abolished by 20 microM esculetin, but was unaffected by piroxicam, a selective cyclooxygenase inhibitor. The effect of LA on invasion was replicated by 0.1 microM 12-HETE, but not by 5-HETE or PGE2; 15-HETE was stimulatory only at a concentration of 1.0 microM. Zymographic and Northern blot analyses showed that these events are accompanied by the induction of 92 kDa isoform type IV collagenase (metalloproteinase-9) enzymic activity and mRNA expression by exogenous LA and 12-HETE, and their suppression by the 12-lipoxygenase inhibitor. These results suggest that the effects of dietary LA on breast cancer cell metastasis in the nude mouse model are due, at least in part, to enhanced 12-HETE biosynthesis, with an associated increase in proteolytic enzyme activity and tumor cell invasiveness.

Relative risk of Alzheimer disease and age-at-onset distributions, based on APOE genotypes among elderly African Americans, Caucasians, and Hispanics in New York City

Apolipoprotein-E epsilon 4 (APOE-epsilon 4) has been consistently associated with Alzheimer disease (AD) and may be responsible for an earlier age at onset. We have previously reported a diminished association between APOE-epsilon 4 and AD in African Americans. Using a new method, which allows inclusion of censored information, we compared relative risks by APOE genotypes in an expanded collection of cases and controls from three ethnic groups in a New York community. The relative risk for AD associated with APOE-epsilon 4 homozygosity was increased in all ethnic groups (African American relative risk [RR]=3.0; 95% confidence interval [CI]=1.5-5.9; Caucasian RR=7.3, 95% CI=2.5-21.6; and Hispanic RR=2.5, 95% CI=1.1-5.7), compared with those with APOE-epsilon 3/epsilon 3 genotypes. The risk was also increased for APOE-epsilon 4 heterozygous Caucasians (RR=2.9, 95% CI=1.7-5.1) and Hispanics (RR=1.6, 95% CI=1.1-2.3), but not for African Americans (RR=0.6, 95% Ci=0.4-0.9). The age distribution of the proportion of Caucasians and Hispanics without AD was consistently lower for APOE-epsilon 4 homozygous and APOE-epsilon 4 heterozygous individuals than for those with other APOE genotypes. In African Americans this relationship was observed only in APOE-epsilon 4 homozygotes. These results confirm that APOE genotypes influence the RR of AD in Caucasians and Hispanics. Differences in risk among APOE-epsilon 4 heterozygote African Americans suggest that other genetic or environmental factors may modify the effect of APOE-epsilon 4 in some populations.

Dual action of metabotropic glutamate receptor agonists on neuronal excitability and synaptic transmission in spinal ventral horn neurons in vitro

A dual action of selective metabotropic glutamate receptor agonists on neuronal excitability and dorsal root-evoked excitatory (DR-EPSPs) and inhibitory (DR-IPSPs) neurotransmission is described for immature rat ventral horn neurons in vitro. Trans-1-Aminocyclopentane-1,3 -dicarboxylate (trans-ACPD), its stereoisomer (1S,3R)-1-aminocyclopentane-1,3-dicarboxylate ((1S,3R)-ACPD) and (2S,3S,4S)-alpha-(carboxycyclopropyl)-glycine (L-CCG-1) produced a concentration-related and alpha-methyl-4 -carboxyphenylglycine (MCPG)-sensitive depolarisation. An (1S,3R)-ACPD- or L-CCG-1-induced increase in intrinsic neuronal excitability was apparently independent of the depolarisation and was observed as (a) a fall in the threshold current required to elicit regenerative excitation and (b) an increased number of spikes to a fixed amplitude step depolarisation. The spike after-hyperpolarisation (AHP) duration and amplitude were reduced, suggesting an mGluR agonist action on potassium channels. Synaptic responses were depressed by the mGluR agonists. (1S,3R)-ACPD or L-CCG-1 reduced the mean +/- S.E.M. peak amplitude of a subthreshold EPSP elicited by low-intensity stimuli likely to recruit only low-threshold sensory afferents. The peak amplitude of longer-latency EPSPs elicited by higher-intensity stimuli likely to recruit high-threshold afferents in addition was attenuated. (1S,3R)-ACPD- or L-CCG-1 reduced the peak amplitude of an IPSP evoked by dorsal root stimulation. These effects on synaptic transmission were likely to be due to the combined activation of postsynaptic and presynaptic metabotropic glutamate receptors. The implications of these data for the physiological role of spinal mGluRs is discussed.

The inhibition of vitamin K3 on rabbit fibroblast proliferation in vitro

Vitamin K3 that is commonly used to treat hemorrhagic diseases can inhibit human lymphatic neoplasms in vitro. This study was undertaken to investigate the effects of vitamin K3 on rabbit conjunctival fibroblast proliferation in cell culture. Vitamin K3 was added to cultured rabbit conjunctival fibroblasts. Remarkable inhibition was observed at a concentration of 4 mg/l. Because of its lower toxicity, vitamin K3 may prove to be of significant value in the treatment of intraocular proliferative disorders.

Dietary linoleic acid-stimulated human breast cancer cell growth and metastasis in nude mice and their suppression by indomethacin, a cyclooxygenase inhibitor

Growth and metastasis to the lung of the human breast cancer cell line MDA-MB-435 in nude mice fed a high-fat (20% wt/wt) high-linoleic acid (LA; 12% wt/wt) diet were significantly reduced by the addition of the cyclooxygenase inhibitor indomethacin to the drinking water at a dose of 10 micrograms/ml (approximately 1 mg/kg body wt). No toxicity was observed in these mice; at 20 micrograms/ml indomethacin, gastric ulcerations occurred. After necropsy, tumor eicosanoids were measured by radioimmunoassay in the control and 10 micrograms/ml indomethacin treatment groups. Levels of the cyclooxygenase products prostaglandin (PG) E (PGE), 6-keto-PGF1 alpha, and thromboxane B2 (TxB2) were significantly reduced in indomethacin-treated mice compared with controls; however, the 6-keto-PGF1 alpha-to-TxB2 ratio was significantly increased. Two lipoxygenase products, 5-hydroxyeicosatetraenoic acid (5-HETE) and 15-HETE, were unaffected, but the 12-HETE levels were increased compared with the untreated high-LA-fed group. Metastases to the lungs in mice fed a high-fat low-LA (2% wt/wt) diet were also reduced compared with those in the high-LA-fed control mice, but whereas tumor cyclooxygenase and lipoxygenase product levels were reduced, no change in the 6-keto-PGF1 alpha-to-TxB2 ratio was observed. The use of selective cyclooxygenase inhibitors may prevent LA-mediated progression of breast cancer at several levels of the metastatic cascade, among which may be interference with tumor cell-vascular endothelial cell interaction and with angiogenesis.

[Study of anti-cerebral thromboembolism injection's activity on experimental arterial thrombosis and its therapeutical mechanism]

Anti-Cerebral Thromboembolism Injection (ACTI), applied intravenously in Cattaneo's animal model of arterial thrombosis, could significantly reduce the weight of thrombus, blood viscosities, plasma TXB2 level and delay the prothrombin time, compared to control group (P < 0.05). From this trial, it was indicated that ACTI's reducing thrombosis action was the result of inhibiting aggregation and releasing of platelets through reducing whole blood viscosities and TXB2 level.

Effects of norcantharidin, a protein phosphatase type-2A inhibitor, on the growth of normal and malignant haemopoietic cells

Cantharidin is a natural toxin that inhibits protein phosphatase type 2A (PP2A) and has antitumour effects in man. We have studied the synthetic analogue, norcantharidin (NCTD), which has less nephrotoxic and phlogogenic side-effects, investigating the effects on the normal haemopoietic system and leukaemia cell growth. Daily intraperitoneal (i.p.) injection of NCTD induced dose and circadian time-dependent transient leucocytosis in normal mice, but did not accelerate bone marrow (BM) regeneration, or have haemopoietic offe-effects following chronic administration. NCTD stimulated the cell cycle progression of granulocyte-macrophage colony-forming cells (GM-CFC), stimulated DNA synthesis and increased the frequency of mitotic cells in short-term human BM cultures. NCTD also stimulated the production of interleukin (IL)-1 beta, colony stimulating activity (CSA) and tumour necrosis factor (TNF)-alpha. Continuous in vitro NCTD treatment, however, inhibited both DNA synthesis and GM-CFC growth. Fluorescence-activated cell sorting (FACS) analysis of DNA profiles and cytological studies in HL-60, K-562 or MRC5V2 (fibroblast) cells indicated that low doses of NCTD accelerated the G1/S phase transition, while higher doses or prolonged incubations inhibited the cell cycle at the G2/M phases or during the formation of postmitotic daughter cells. Electron microscopy revealed that NCTD impaired the neogenesis of chromatin material and nuclear membrane during the M/G1 phase transition in K-562 cells. The biphasic effect of NCTD may be due to inhibition of PP2A activity, which regulates the cell cycle, both at the restriction point and at the G2 and M phases. Our data provide new insight into the cellular and molecular actions of NCTD, and partly explain its therapeutical effects in cancer patients.

Suppression of type IV collagenase in MDA-MB-435 human breast cancer cells by eicosapentaenoic acid in vitro and in vivo

Dietary supplementation with 4% eicosapentaenoic acid (EPA), a long-chain polyunsaturated fatty acid, suppressed the development of lung metastases in nude mice from MDA-MB-435 human breast cancer cell mammary fat pad solid tumors. Zymography of primary tumor homogenates showed that this inhibition of metastasis was associated with reduced levels of 92-kDa type IV collagenase gelatinolytic activity; this isoform has been previously associated with the metastatic phenotype. The 72-kDa isoform, which was also present, may have arisen from the cancer cells, or tumor-associated host cells. In vitro, the incorporation of EPA, 0.25-1.0 micrograms/ml into the medium caused a concentration-related suppression of cultured MDA-MB-435 cell 92-kDa type IV collagenase mRNA expression.

Immunohistochemical localization of the low molecular weight stress protein HSP27 following focal cerebral ischemia in the rat

We immunohistochemically investigated the induction and localization of a low-molecular weight stress protein, HSP27, in the rat brain following 1 hr of middle cerebral artery occlusion in comparison with those of HSP70. The brains were perfusion-fixed after 4 h, 1 day, 3 days, 7 days, and 14 days of reperfusion. Frozen sections were then prepared and used for immunohistochemistry. In normal brains, we observed no immunoreactivities to HSP70 and HSP27. HSP70 was localized predominantly in neurons in areas peripheral to the ischemic center after 1 day and 3 days, and in endothelial cells and perivascular cells within the ischemic center after 1 day. In contrast, HSP27 was induced in microglia in the ischemic center after 4 h, and then in reactive astrocytes distributed widely in the ipsilateral hemisphere and in part of the contralateral hemisphere after 1 through 14 days. In the center of ischemia where infarction developed, only nonspecific staining was seen. Thus, the expression patterns of HSP70 and HSP27 were quite different with regard to cell type, distribution, and time course following focal cerebral ischemia. HSP70 may be a sensitive marker of acute neuronal stress in the penumbral areas, whereas HSP27, which was most prominently induced in reactive astrocytes in periischemic and remote areas, may be a component of glial reaction to injury.

The hematon, a morphogenetic functional complex in mammalian bone marrow, involves erythroblastic islands and granulocytic cobblestones

The development of pluripotential hematopoietic stem cells (PHSC) requires the continuous support provided by the bone tissue and bone marrow (BM) stromal cells. The basic rule of spatial and temporal organization of the distinct stromal cells and differentiating hematopoietic cells in the course of development, regenerative morphogenesis, or under homeostasis is still poorly understood. We have identified a cohort of preformed, multicellular aggregates in human BM aspirates that we have called hematons. This study shows that homologous hematon complexes can be isolated from the femoral BM shaft of normal mice. Cytologic analysis showed that both human and mouse hematons contained finely arborized endothelial cells, fibroblasts, preadipocytes, lipid-laden cells, and resident macrophages. This stromal cell web was tightly packed with hematopoietic cells comprising primitive cells with marrow-repopulating ability (MRA); day-8 and -12 colony-forming unit-spleen (CFU-S8 and -S12) in the mouse hematon; and high proliferative potential colony-forming cell (HPP-CFC), burst-forming unit-erythroid (BFU-E), granulocyte-macrophage-CFU (GM-CFU), as well as differentiated postmitotic cell populations in both human and mouse hematons. A cohort of single hematons produced a large, but variable, number of myeloid and erythroid cells, as well as megakaryocytes, in organotypic microculture, indicating the heterogenous growth potential of individual hematons. Each hematon developed into a complex, adherent colony in long-term liquid culture, which involves erythroblastic islands and granulocytic cobblestones. The hematons, isolated from 5-fluorouracil (5-FU)-treated mice, contained more HPP-CFC, BFU-E, and GM-CFU populations than the buffy coat (BC) fraction and produced significantly more CFU than normal hematons in organotypic microcultures. The present results provide further support for our hypothesis that the hematon is a tissue-specific complex structure that plays a critical roles in the maintenance of homeostasis and in the regenerative morphogenesis of mammalian BM.

Effect of endothelin-1 on the development of hemorrhagic pancreatitis in rats

BACKGROUND

It has been hypothesized that microcirculatory disturbance plays an important role in the development of severe pancreatitis. In this study we investigated the effects of exogenous endothelin-1 on the development of severe pancreatitis in rats.

METHODS

Acute pancreatitis was induced by two intraperitoneal injections of cerulein (10 micrograms/kg body weight). Endothelin-1 was administered via an abdominal aortic catheter as a bolus of 250-750 pmol/kg BW every hour for 4 h.

RESULTS

Remarkable morphologic changes in the pancreas, including hemorrhage, and increases in serum amylase level and active elastase content in pancreatic tissue were observed in rats treated with cerulein plus endothelin-1 in a dose-dependent manner 5 h after the first cerulein injection. Local pancreatic blood flow decreased significantly, and microcirculatory disturbances in the pancreas were demonstrated.

CONCLUSIONS

These results suggest that endothelin-1 causes pancreatic microcirculatory disturbance and might be a contributing factor in the aggravation of acute pancreatitis.

Bromocriptine protects against delayed neuronal death of hippocampal neurons following cerebral ischemia in the gerbil

Bromocriptine, a dopamine D2 receptor agonist, has widely been used for patients with Parkinson's disease. In this study, we examined its neuroprotective effects against neuronal damage in the CA1 subfield of the hippocampus following experimental cerebral ischemia in the Mongolian gerbil. Forebrain ischemia was induced by occlusion of bilateral common carotid arteries for 3 min. Bromocriptine, at a dose of 0.3 or 3 mg/kg, was injected i.p. 30 min before the onset of ischemia. Histopathological observations showed that neuronal damage to hippocampal CA1 neurons, which was seen 7 days after ischemia in vehicle-treated animals, was prevented by bromocriptine treatment. Immunohistochemical staining for copper/zinc superoxide dismutase and manganese superoxide dismutase decreased markedly in the CA1 neurons of vehicle-treated animals 2 days after ischemia when histological neuronal destruction was not yet seen, but was well preserved in bromocriptine-treated animals. The present findings show that bromocriptine protects against ischemia-induced neuronal damage, and that the mechanism of the neuroprotection may relate to the preservation of SODs. Bromocriptine, which was recently shown to be a potent free radical scavenger, may have a potent neuroprotective action against disorders including ischemic stroke.

Immunohistochemical localization of superoxide dismutase in the hippocampus following ischemia in a gerbil model of ischemic tolerance

Pretreatment of the gerbil brain with a 2-min period of sublethal ischemia protects against neuronal damage following a subsequent 3-min period of ischemia, which normally destroys pyramidal neurons in the CA1 region of the hippocampus. To clarify the role of superoxide dismutase (SOD) in this ischemic tolerance, we immunohistochemically investigated the alterations in copper-zinc SOD (CuZnSOD) and manganese SOD (Mn-SOD) in the gerbil hippocampus following 3-min ischemia with or without the first mild ischemia. Normal hippocampus showed an intense CuZnSOD immunostaining in pyramidal neurons but relatively less MnSOD immunostaining. MnSOD, but not CuZnSOD, immunoreactivity increased after the first ischemia. Both CuZnSOD and MnSOD immunoreactivities decreased throughout the hippocampus 4 h after 3 min of ischemia both with and without the first ischemia. The immunostaining recovered in resistant regions (CA3 and dentate gyrus) after 1 day in both groups and in the pretreated CA1 after 2 days. Without pretreatment, however, the immunostaining never recovered in the vulnerable CA1 region. The results suggest that ischemic tolerance is induced in part by enhanced synthesis of MnSOD in the tolerance-acquired hippocampus. Both CuZnSOD and MnSOD immunoreactivities decreased after the second ischemia even in the pretreated hippocampus in the early reperfusion periods, but ischemic tolerance facilitated the recovery from the postischemic reductions in SOD immunoreactivity.

Effects of linoleic acid and gamma-linolenic acid on the growth and metastasis of a human breast cancer cell line in nude mice and on its growth and invasive capacity in vitro

It has been reported that gamma-linolenic acid (GLA)-rich diets suppress mammary carcinogenesis and transplanted tumor growth and that GLA inhibits the growth of cultured human cancer cell lines. We compared the effects of dietary GLA and linoleic acid (LA) on the growth of MDA-MB-435 human breast cancer cells and their expression of the metastatic phenotype in vivo and in vitro. Athymic nude mice (30/dietary group) were fed isocaloric diets containing 20% (wt/wt) fat but providing 8% GLA or LA for 7 days, and 10(6) tumor cells were then injected into a thoracic mammary fat pad. The diets were continued for a further 11 weeks. The primary tumor growth rates were similar in mice from the two dietary groups; there was a nonstatistically significant trend for the incidence of macroscopic lung metastases and the total lung metastatic volumes to be higher in the GLA-fed mice (79% and 40.1 +/- 13.9 mm3) than in the LA-fed mice (64% and 15.5 +/- 5.4 mm3). The tumor cell phospholipids from the 8% GLA-fed mice contained significantly lower LA levels but higher arachidonic acid levels (both p < 0.001) than those from 8% LA-fed mice. Also the arachidonate-derived eicosanoids (prostaglandin E, leukotriene B4, and 5-, 12-, and 15-hydroxyeicosatetraenoic acids) were significantly higher in tumors from the 8% GLA group. Zymography showed higher 92-kDa type IV collagenase activity in tumors from 8% GLA-fed mice. In vitro, GLA and LA, at 0.5-2 micrograms/ml, stimulated MDA-MB-435 cell growth; 10 micrograms/ml was mildly inhibitory. Whereas LA stimulated tumor cell invasion and 92-kDa type IV collagenase production in vitro, GLA inhibited invasion and did not induce activity of the proteolytic enzyme. Our results do not support the hypothesis that supplementation with GLA would exert a beneficial effect on the progression of an existing breast cancer, perhaps because it is metabolized in vivo to arachidonate-derived eicosanoids that are known to be involved in the metastatic process.

Effects of linoleic acid on the growth and metastasis of two human breast cancer cell lines in nude mice and the invasive capacity of these cell lines in vitro

The purpose of the study was to compare the effects of dietary linoleic acid (LA) intake on the growth and metastasis of MDA-MB-435 and MDA-MB-231 human breast cancer cells in nude mice, together with their invasive capacity and secretion of type IV collagenase (gelatinase) in vitro. Each tumor cell line (10(6) cells) was injected into a right-sided mammary fat pad in 60 mice with equal numbers (30 mice/group) assigned to isocaloric diets containing 23% (w/w) total fat and 2% or 12% (w/w) LA. The MDA-MB-435-cell mammary fat pad tumors became palpable earlier and initially they grew more rapidly, but by 6 weeks the MDA-MB-231-cell tumors exhibited an acceleration of growth which was enhanced by the high-LA diet. At necropsy, 12 weeks after the tumor cell injections, the mean weight [10.2 +/- 1.4 g(SEM)] of mammary fat pad MDA-MB-231 cell tumors in 12% LA-fed mice was significantly higher (6.7 +/- 1.4 g) than that of the mice fed 2% LA; also, it was higher than that of MDA-MB-435 cell tumors in the 12% LA-fed mice (3.6 +/- 0.1 g) or the 2% LA-fed mice (3.3 +/- 0.1 g) (each P < 0.001). Mice fed the 12% LA diet had a higher incidence of grossly visible MDA-MB-435 cell pulmonary metastatic nodules than those fed the 2% LA diet (67% versus 33%; P < 0.02), more metastatic lesions (5.7 +/- 1.6 versus 2.3 +/- 0.8; P < 0.05), and greater total volumes (62.0 +/- 25.9 versus 24.8 +/- 9.0 mm3; P < 0.02) per mouse. Of the MDA-MB-231 cell tumor-bearing mice, only 1 in the 12% LA dietary group and 2 in the 2% LA dietary group had macroscopic nodules but the incidence of microscopic metastases was 68 and 42%, respectively. The MDA-MB-231 cell line exhibited a relatively high capacity for invasion in vitro and constitutively high levels of both total type IV collagenolytic activity and M(r) 92,000 gelatinase production which were unaffected by LA. In contrast, MDA-MB-435 cells had approximately only one-sixth the invasive capacity and secreted a relatively low level of type IV collagenase and little of the M(r) 92,000 gelatinase; both invasion and enzyme production were stimulated by LA.

Induction of heat shock protein 70 and glial fibrillary acidic protein in the postischemic gerbil hippocampus

Immunohistochemical changes of heat shock protein 70 (HSP 70) and glial fibrillary acidic protein (GFAP) were investigated in the gerbil hippocampus 1 h-7 days after 10 min of cerebral ischemia. Transient cerebral ischemia caused HSP 70 expression in GFAP-positive astrocytes in a delayed fashion, as compared with a rapid induction in vulnerable neurons such as hilar neurons. The present results may offer clues to elucidate the mechanisms of ischemic neuronal damage.

[Experimental study on compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs]

The article describes the effectiveness of compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs to the animal model with endotoxemia and nonspecific inflammation. The compatible application reduces PGE2, endotoxin blood concentration and reduced viscosity of whole blood, decreases Evans blue extravasation volume and pes swelling percentage, increases serum cortisol content and enhances fibrinolytic activity. The experimental result shows that in most cases these two drugs work better when used in combination which implies that compatible application is more effective in detoxification, antiinflammation and inflammation recovery.

Apoptotic cell death induced by optic nerve lesion in the neonatal rat

Cell death can be ascribed to one of two distinct modes of degeneration: apoptosis (programmed or active cell death) or necrosis (passive degeneration). While apoptosis is generally assumed to occur in physiological conditions such as normal development or tissue turnover, necrotic cell degeneration is induced in pathological situations. Here we report that also in a pathological situation, such as after axotomy in the CNS, apoptotic type of cell death comes into play: following intracranial transection of the optic nerve in the neonatal rat in vivo, retinal ganglion cells undergo an active, apoptotic cell death. In fact, the administration of protein synthesis inhibitors (actinomycin D and cycloheximide) prevents the appearance of pyknotic nuclei as well as of fragmented DNA of ganglion cells at 24 hr postlesion. Correspondingly, the number of surviving cells after actinomycin D and cycloheximide treatment is comparable to normal, unlesioned retinas. In addition, cycloheximide decreases the number of pyknotic ganglion cells during spontaneous cell death.

An immunohistochemical study of parvalbumin containing interneurons in the gerbil hippocampus after cerebral ischemia

We investigated postischemic changes of non-pyramidal neurons in the gerbil hippocampus 1 h - 7 days after 10 min of cerebral ischemia, with parvalbumin and microtubule-associated protein 2 (MAP2)-immunohistochemistry. Parvalbumin-immunoreactive interneurons in the hippocampus were unaffected up to 24 h after ischemia. A slight reduction of the immunoreactivity in neuronal processes was seen in the hippocampal CA1 sector 48 h after ischemia. Seven days after ischemia, a marked loss of parvalbumin-immunoreactive interneurons was observed in the hippocampal CA1 and CA3 sectors. Furthermore, reduced staining in the dentate granular and molecular layers was observed. MAP2-immunoreactive pyramidal neurons in the hippocampus were unchanged up to 48 h after ischemia. Seven days after ischemia, a severe loss of MAP2 immunoreactivity was found in the hippocampal CA1 and CA3 neurons and dentate hilar neurons. However, scattered CA1 neurons, most likely interneurons, preserved MAP2 immunoreactivity. The results demonstrate that transient cerebral ischemia can cause a loss of parvalbumin-immunoreactive interneurons in the hippocampus. Furthermore, some interneurons seem to lose parvalbumin synthesis. Although dentate granule cells are resistant to ischemia, considerable reductions of afferent input was suggested by parvalbumin staining.

Ischemic tolerance can be induced repeatedly in the gerbil hippocampal neurons

We investigated whether ischemic tolerance can be induced repeatedly in the gerbil hippocampal neurons. The gerbils were firstly treated with two episodes of 2-min forebrain ischemia 1 day apart, which procedure is known to induce ischemic tolerance. After 4 weeks of recirculation, the animals were subjected to a 2-min period of preconditioning ischemia again and then to a 3-min period of ischemia after 3 days. The hippocampal CA1 neurons were destroyed 7 days after 3-min ischemia without the second preconditioning but not in animals with the second preconditioning. Thus, ischemic tolerance can be induced repeatedly when the first ischemic tolerance has disappeared.

Delayed damage of striatal interneurons after cerebral ischemia in the gerbil

Immunohistochemical changes of striatal interneurons in the gerbil were investigated 1 h-7 days after 10 min cerebral ischemia. Marked reduction of parvalbumin-immunoreactive interneurons was seen in the striatum from 24 h after ischemia. MAP2 (microtubule-associated protein 2) immunoreactivity markedly decreased in striatal neurons 5 h after ischemia but was unaffected in interneurons. Thereafter, a severe loss of MAP2 immunoreactivity in the interneurons was found 48 h and 7 days after ischemia. The results demonstrate that transient cerebral ischemia can cause a loss of parvalbumin and MAP2 immunoreactivity in interneurons in the dorsolateral striatum in a delayed fashion as compared with a rapid loss of striatal neurons.

An immunohistochemical observation of manganese superoxide dismutase in rat substantia nigra after occlusion of middle cerebral artery

We investigated immunohistochemically the localization and changes of manganese superoxide dismutase (Mn-SOD) in substantia nigra after 1 h of middle cerebral artery (MCA) occlusion in the rat with reperfusion periods of 1, 3, 7, and 14 days. In normal rats, Mn-SOD immunoreactivity was observed intensely in many large neurons in substantia nigra pars reticulata (SNr) and weakly in neurons in the pars compacta (SNc). The immunoreactivity of the neurons in both SNr and SNc was reduced after 1 day and almost lost 3 days after MCA occlusion, although these neurons showed completely normal morphology. The immunoreactivity recovered only in the large neurons in SNr from the 7th day and well preserved after 2 weeks, when SNr showed obvious atrophy. The results indicate that oxidative stress may be involved in the pathogenesis of the secondary postischemic neurodegeneration in SN.

An immunohistochemical study of copper/zinc superoxide dismutase and manganese superoxide dismutase following focal cerebral ischemia in the rat

We investigated immunohistochemically the localization and changes of copper/zinc superoxide dismutase (CuZn-SOD) and manganese superoxide dismutase (Mn-SOD) in the rat brain following 1 h of middle cerebral artery (MCA) occlusion. In normal brain, immunoreactivity to both SODs was observed in medium-sized neurons in the striatum and in many neurons in the neocortex. Mn-SOD was predominantly stained in cortical interneurons. The immunostaining of both SODs rapidly decreased or disappeared in neurons in the lateral segment of the striatum (ischemic center) 4 h after MCA occlusion, when the neurons were degenerating. Most neurons in the neocortex (ischemic penumbra) decreased their CuZn-SOD immunoreactivity but not Mn-SOD immunoreactivity 4 h after ischemia, when only a few neurons showed histopathological changes. CuZn-SOD immunoreactivity in almost all cortical neurons disappeared 1 day after ischemia, but Mn-SOD immunoreactivity was still preserved in interneurons, when cortical neurons showed typical pathological changes. Some cortical neurons in the boundary zone between normal and infarcted areas showed intense immunostaining to both SODs and glial SOD immunoreactivity appeared after 3 and 7 days. These results suggest that early loss of the scavenging system of free radicals may lead to neuronal damage after ischemic insult, and that induced SODs in the boundary zone between the normal and infarcted areas may act as a defense mechanism against damage.

Protective effects of a novel calcium antagonist with platelet-activating factor-antagonistic action, F-0401, against ischemic brain damage

The protective effects of a novel dihydropyridine calcium antagonist with platelet-activating factor-antagonistic action, F-0401, on ischemic brain damage were investigated using experimental ischemia models in rats and gerbils. F-0401 (1 and 10 mg/kg, i.p.) prevented increases in water content, determined by the wet-dry method, in ischemic areas 24 hr after 1 hr of middle cerebral artery occlusion in the rat. Pretreatment with F-0401 (1 and 10 mg/kg, i.p.) prevented extravasation of Evans blue dye in the brain following 2 hr of bilateral carotid artery occlusion and 2 hr of reperfusion in the rat. Pretreatment with F-0401 (1 and 10 mg/kg, i.p.) protected against neuronal damage to hippocampal CA1 pyramidal cells following 3 and 5 min of forebrain ischemia in the gerbil. Immunostaining against microtubule-associated protein-2 also demonstrated preservation of CA1 neurons in F-0401-treated animals. Thus, this study shows that F-0401 prevents the occurrence of brain edema, disruption of blood-brain barrier and neuronal damage caused by cerebral ischemia. The results demonstrate that F-0401 may be a powerful candidate as a therapeutic agent in the treatment of acute stroke in man.

In vitro investigation of blood compatibility of Ti with oxide layers of rutile structure

Structure characteristics of titanium oxide layer on titanium matrix were investigated by Rutherford Backscattering Spectroscopy (RBS), Auger Electron Spectroscopy (AES) and X-ray diffraction. It has been identified that the titanium oxide layers had rutile structure. The blood compatibility of the titanium oxide layers of different thickness was studied by blood clotting time measurement. It was shown that as the thickness of the titanium oxide layers increased, blood compatibility of these layers was obviously improved.

[Chemical constituents of Notopterygium incisium Ting. III: Chemical constituents isolated and identified from petroleum ether extracts of N. incisium Ting]

Six chemical compounds were isolated from the roots and rhizoma of Notopterygium incisium by column chromatography and preparative thin-layer chromatography, and identified by chemical and spectroscopic analysis as beta-sitosterol, oleic acid, linoleic acid, columbianetin, pregnenolone and ferulic acid. The presence of pregnenolone in the genus Notopterygium has not been reported.

Stimulation of type IV collagenase expression by linoleic acid in a metastatic human breast cancer cell line

Linoleic acid (LA), an omega-6 fatty acid, enhanced the appearance of type IV collagenase activity in culture medium conditioned by the metastatic MDA-MB-435 human breast cancer cell line; this effect was maximal with 0.75 microgram/ml LA. Zymography showed an increase in the gelatinolytic 92 kDa metalloproteinase, a form associated with the metastatic phenotype, during culture in the presence of 0.75 microgram/ml LA. Indomethacin, 20 micrograms/ml, completely suppressed the stimulation of collagenase by LA, suggesting a role for the eicosanoids. The tumor cells expressed mRNA for both the 72 and 92 kDa isoforms of type IV collagenase. Basal levels of the 92 kDa mRNA were much higher; both were up-regulated by LA despite the absence of detectable 72 kDa activity in conditioned medium.

Androgens regulate proliferation of human prostate cancer cells in culture by increasing transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF)/TGF-alpha receptor

Androgens affect growth of the prostate gland and many prostate cancers. Androgens could mediate their mitogenic effects on prostate cells by an autocrine loop involving epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha that bind to the EGF/TGF-alpha receptor. We examined the effects of 5 alpha-dihydrotestosterone (DHT) and testosterone (T), EGF, and EGF-alpha on cell proliferation and 3H-thymidine incorporation in an androgen-dependent human prostate cancer cell line, ALVA101, in serum-free medium. The regulation of TGF-alpha and EGF/TGF-alpha receptor messenger RNA (mRNA) levels were determined by Northern blot analysis and EGF/TGF-alpha receptor protein by immunoblot. After 24 h of treatment of ALVA101 cells with DHT (10(-8) M) or T (10(-8) M), TGF-alpha mRNA levels increased 3- and 2.5-fold, respectively, and EGF/TGF-alpha receptor mRNA levels 2- and 1.5-fold, respectively. Cell numbers increased at day 5 in response to 10(-8) M DHT (18%, P < 0.01), 10(-8) M T (15%, P < 0.01), 20 ng/ml EGF (16%, P < 0.01), and 50 ng/mL TGF-alpha (34%, P < 0.01). DHT combined with TGF-alpha or T combined with EGF increased cell number 43% and 40% above control, respectively (P < 0.01 vs. DHT, P < 0.05 vs. TGF-alpha, T, EGF alone). The anti-EGF/TGF-alpha receptor antibody (528) blocked the cell proliferation induced by either DHT or TGF-alpha. We conclude that DHT and T stimulate synthesis of TGF-alpha and EGF/TGF-alpha receptor mRNAs and EGF/TGF-alpha receptor content in ALVA101 cells. This mitogenic effect of androgen on ALVA101 cells may involve TGF-alpha and the EGF/TGF-alpha receptor autocrine loop.

An immunohistochemical study of copper/zinc superoxide dismutase and manganese superoxide dismutase in rat hippocampus after transient cerebral ischemia

We investigated the changes of copper/zinc superoxide dismutase (CuZn-SOD) and manganese superoxide dismutase (Mn-SOD) in the rat hippocampus after 10 min of cerebral ischemia induced by 4-vessel occlusion. The rats were allowed to survive for 4 h, 1 day, 3 days, and 7 days after ischemia. The distribution of SODs were determined by immunohistochemical staining with antibodies against rat CuZn-SOD and Mn-SOD. CA1 pyramidal neurons and granule cells of the dentate gyrus showed intense CuZn-SOD immunoreactivity, whereas CA3 and CA4 neurons showed weaker immunostaining than CA1 neurons in normal animals. The immunoreactivity was reduced by 4 h after ischemia in CA1, CA3, and CA4 neurons when no histological damage was observed. Mn-SOD immunostaining revealed more intense immunoreactivity in CA3 pyramidal neurons than in CA1 neurons in normal animals. Interneurons in the CA1 and CA3 regions and the dentate hilus also showed high Mn-SOD immunostaining. Although CA1 neurons lost Mn-SOD immunoreactivity by 1 day after ischemia, CA3 neurons and interneurons retained the immunoreactivity and preserved intact cell contour after ischemia. In addition, reactive glial cells, which were differentiated by immunocytochemical staining against glial fibrillary acidic protein for reactive astrocytes and histochemical staining for reactive microglial cells, were intensely stained for CuZn-SOD and Mn-SOD after ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical localization of ubiquitin in gerbil hippocampus with induced tolerance to ischemia

Using immunohistochemistry, we visualized the localization of ubiquitin in the gerbil hippocampus following 3 min of ischemia with or without pretreatment with 2 min of sublethal ischemia and 3 days of reperfusion. Ubiquitin immunoreactivity in the hippocampus disappeared 4 h after 3 min of ischemia both with and without pretreatment. The immunoreactivity in the CA3 and the dentate gyrus recovered by 24 h, but never recovered in the CA1, where delayed neuronal death takes place, without pretreatment. However, the pretreatment, which protects against CA1 neuronal damage, led to recovery of ubiquitin immunoreactivity in the CA1 by 48 h. Thus, recovery of ubiquitin may be a prerequisite to neuronal survival after ischemia and the role of ubiquitin in ischemic tolerance was suggested.

Immunohistochemical visualization of heat shock protein-70 in the gerbil hippocampus following repeated brief cerebral ischemia

Recent experiments have shown that neuronal damage following repeated cerebral ischemic insults is more extensive than the damage after a single equivalent period of ischemia. To clarify the mechanism of this cumulative neuronal damage after repeated ischemia, we visualized the localization of heat shock protein-70 (HSP70), a marker of neuronal stress, with immunohistochemistry using a monoclonal antibody. Mongolian gerbils were subjected to three 2-min forebrain ischemic insults spaced at 1-h intervals and to a single 6-min period of ischemia. The animals were killed 24 and 48 h after ischemia. Hippocampal CA1 pyramidal neurons, which are destined to die, showed no HSP70 staining 24 and 48 h after three 2-min ischemic insults, but showed a mild to moderate staining after 6 min of ischemia, suggesting more severe damage after repeated ischemia. CA3 neurons, which are resistant to ischemia, were intensely stained with HSP70 antibody following 6 min of ischemia but was stained only slightly after three 2-min ischemic insults, showing less stress after repeated ischemia. Thus, thresholds for cell damage are obviously different among different cell populations within the hippocampus; the different neuronal populations respond differently to single and repetitive ischemia. The result suggests that cumulative neuronal damage after repeated sublethal ischemic insults is produced by increased susceptibility to subsequent insults when ischemic stress reaches certain thresholds that are different among different neuronal populations.

Reduction of HSP70 and HSC70 mRNA inductions by bifemelane hydrochloride after transient ischemia in gerbil brain

The effect of bifemelane hydrochloride (BFH) on the induction of heat shock protein (HSP) 70 and heat shock cognate protein (HSC) 70 mRNAs after transient global ischemia in gerbil brain was investigated by in situ hybridization using cloned cDNA probes selective for each mRNA species. Following 3.5 min of ischemia, HSP70 and HSC70 mRNAs were induced in all hippocampal cells. The CA1 cells were almost lost by 7 days. Treatment with BFH twice before and after ischemia (total 60 mg/kg, i.p.) reduced the induction of HSP70 and HSC70 mRNAs both at 8 h and 1 day of the reperfusion, and about half of the CA1 cells survived at 7 days. Thus, the reduction of HSP70 and HSC70 mRNA inductions after ischemia may suggest that BFH reduced intra- and/or post-ischemic stress, and protected CA1 cells from ischemic damage.

The prognostic value of the HNK-1 (Leu-7) antigen in prostatic cancer--an immunohistochemical study

The anti-HNK-1 (Leu-7) monoclonal antibody (MAb) was revealed to be reactive with noncancerous and cancerous prostatic epithelial cells, although this antibody was originally found to be reactive against natural killer cells. However, the prognostic significance of HNK-1 antigen in prostatic cancer patients remains unknown. The expression of HNK-1 antigen on prostatic cancer was investigated immunohistochemically using the avidin-biotin-peroxidase complex (ABC) method with the anti-HNK-1 monoclonal antibody. Of the 52 patients with prostatic cancer, 49 patients (94%) showed reactivity to anti-HNK-1 MAb and the immunoreaction was associated with the histological differentiation of prostatic cancer. Well differentiated cancer showed the highest percentage of positively stained cancer cells and poorly differentiated cancer showed the lowest percentage. No statistically significant differences existed between groups classified by stage, although the more advanced cancers tended to have weaker reactions. The five-year survival rate and interval free of progression were then studied using the Kaplan-Meier method on 33 patients with stage D2 disease who had received endocrine therapy. The findings indicated that a high survival rate and a longer interval free of progression were associated with a higher fraction of positively stained cancer cells. In conclusion, the expression of HNK-1 antigen on prostatic cancer may be a useful prognostic factor in patients with prostatic cancer.