Prescription of non-steroidal anti-inflammatory drugs

BACKGROUND AND PURPOSE: Tacrolimus, an immunosuppressant agent, has been shown to reduce tissue injury and leukocyte accumulation after transient ischemia. This study was designed to evaluate quantitatively the inhibitory effects of tacrolimus on leukocyte rolling and on subsequent leukocyte accumulation in vivo after transient retinal ischemia and the protective effects of tacrolimus on ischemia-induced neural damage. METHODS: Retinal ischemia was induced for 60 minutes in anesthetized pigmented rats by temporary ligation of the optic sheath. Tacrolimus was administered at 10 minutes after ischemic induction. At 4, 12, 24, and 48 hours after reperfusion, leukocyte behavior in the retinal microcirculation was evaluated in vivo with acridine orange digital fluorography. After 7 days of reperfusion, ischemia-induced retinal damage was evaluated histologically. RESULTS: Treatment with tacrolimus suppressed leukocyte rolling; the maximum number of rolling leukocytes was reduced by 60.1% at 12 hours after reperfusion (P<0.05). In tacrolimus-treated rats, the velocity of rolling leukocytes was significantly faster than in vehicle-treated rats (P<0.01). The subsequent leukocyte accumulation was reduced by 61.6% at 24 hours after reperfusion (P<0.01). Histological examination demonstrated the protective effect of tacrolimus on ischemia-induced retinal damage, which was more substantial in the inner retina (P<0.01). CONCLUSIONS: The present study demonstrated the inhibitory effect of tacrolimus on leukocyte rolling and on subsequent leukocyte accumulation and the therapeutic potency to neural injury after transient retinal ischemia.     

Image generation of serotonin synthesis rates using alpha-methyltryptophan and PET

PURPOSE: The objectives of this study were to examine whether preconditioning can decrease ischemic damage to the retina, by electroretinographic assessment of visual function and by histologic examination of retinal structure; to investigate the time course of the effectiveness of preconditioning; and to determine whether protein synthesis is involved. METHODS: Retinal ischemia was produced for 60 minutes in anesthetized Sprague-Dawley rats. Recovery after ischemia was measured by electroretinography for a maximum period of 7 days. Retinal sections that were sliced 1 micron thick were examined 7 days after ischemia. Retinal ischemia for 5 minutes constituted the preconditioning stimulus. To assess the time course of preconditioning, animals first underwent preconditioning and then 60 minutes of ischemia 1, 24, 72, or 168 hours later; or they underwent a 5-minute sham experiment and 60 minutes of ischemia 24 hours later. An additional group of rats received 0.4 mg/kg cycloheximide, the protein synthesis inhibitor, intraperitoneally before preconditioning and underwent 60 minutes of ischemia 24 hours later. RESULTS: In contrast to the nonpreconditioned rats, preconditioned rats had complete recovery of the a- and b-waves compared with preischemic baseline amplitudes, and ischemia-induced histologic damage was completely prevented when preconditioning was performed 24 or 72 hours (but not 168 hours) before ischemia. Separation of preconditioning and 60 minutes of ischemia by 1 hour caused an even greater impairment of functional retinal recovery compared with that seen in sham-preconditioned rats. Severe histologic damage was also noted. Block of protein synthesis by cycloheximide completely attenuated the protective effect of preconditioning. CONCLUSIONS: Preconditioning induces profound retinal tolerance to ischemia in vivo. The absence of a protective effect of preconditioning when there was a 1-hour or a 168-hour separation between the preconditioning stimulus and ischemia and the inhibition of preconditioning by cycloheximide support the hypothesis that a transient change in protein expression is necessary to provide this protection.     

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50 eyes of 30 Sprague-Dawley rats were subjected to 60 minutes of pressure-induced ischemia, then fixed for light and electron microscopy with no reperfusion, or reperfusion after 30 minutes, 1, 2 or 4 hours, and 1 or 3 days from the time ocular ischemia was relaxed. The TdT-mediated dUTP-biotin nick end labeling (TUNEL) method revealed apoptotic signs at the inner retina as early as 1 hour after reperfusion. However, the incidence of apoptotic signs with the TUNEL method did not accord with the results of electron microscopic examination. During the time after the reperfusion started, especially after more than 4 hours, apoptotic signs became obvious and extended from the inner to the outer retina. These apoptotic findings could be seen with both the TUNEL method and electron microscopy. By 3 days after the reperfusion, necrotic cells in the ganglion cell layer, and the inner and outer nuclear layer became more prominent than apoptotic cells. These results may provide a baseline for therapeutic strategy and the prognosis of ischemia-reperfusion injury in the retina.     

Pretreatment with intraventricular aurintricarboxylic acid decreases infarct size by inhibiting apoptosis following transient global ischemia in gerbils

The goal of this study was to determine whether aurintricarboxylic acid (ATA), an endonuclease inhibitor known to inhibit apoptosis, could ameliorate cell damage in a gerbil model of transient ischemia. Transient ischemia was induced in gerbils by bilateral carotid artery occlusion for a period of 5 minutes. Four micrograms of ATA was administered intraventricularly 1 hour before ischemia, and the brains were assessed histologically 1 week later to quantitate cell loss in the vulnerable CA-1 subsector of the hippocampus. In a separate set of experiments, 4 microg of ATA was administered intraventricularly 1 hour before ischemia and the brains were assessed for evidence of DNA fragmentation by the TUNEL method. There was only a 16% cell loss compared with nonischemic controls in animals pretreated with ATA that was significantly less (p < 0.05) than the 48% cell loss in animals pretreated with saline alone. TUNEL-positive cells were first evident at 3 days and were still present at 7 days subsequent to ischemia. Maximal staining occurred at 4 days. Pretreatment with ATA virtually eliminated TUNEL staining at 4 days. These results support the hypothesis that the delayed cell death secondary to transient ischemia is, in part, apoptotic. Furthermore, ATA afforded significant neuronal protection and prevented DNA fragmentation.     

Effects of 3,3'-iminodipropionitrile on the peripheral structures of the rat visual system

Adult male Long-Evans rats received 3,3'-iminodipropionitrile (IDPN; 400 mg/kg i.p.) and were killed one day after one dose, or one, three, seven, thirty-five, or seventy day(s) following 3 consecutive daily doses for histological analysis of the eye. Histological alterations in visual structures were not observed before one day after the third dose of IDPN. Somato-dendritic swelling of cells in the inner nuclear (IN) layer was seen prior to retinal detachment (1 day after cessation of dosing) followed by progressive retinal degeneration (35 and 70 days). IDPN exposure resulted in opacification of the cornea and vascular hemorrhaging into the subretinal space (3 days) followed by complete detachment of the retina (7 days). The corneal opacification was transient and resolved by 14 days post-treatment. The retina underwent complete spontaneous reattachment between 35 and 70 days after IDPN administration. A subsequent experiment was performed to characterize the dose-response of IDPN on retinal histology, 2 weeks after the last dose (0, 100, 200, 400 mg/kg x 3 days). In the dose-response experiment, retinal detachment and degeneration in the IN layer were only apparent in the 400 mg/kg dose group. However, increased GFAP immunoreactivity in the retina was observed in the 200 mg/kg dose group without overt retinal pathology. Results indicate that the corneal opacification, vascular hemorrhaging, and detached retinae recovered in a time-dependant manner, while neurodegeneration of the visual retina was progressive, even after the retina had reattached. The present study indicates that this toxicant may have direct effects on both neural and non-neural structures, and characterizes the time-course and dose-response of histopathological changes in the retina.     

Delayed involution of the mammary epithelium in BALB/c-p53null mice

In mammals, weaning of neonates and subsequent milk stasis initiates removal of the secretory epithelium of the mammary gland by apoptosis. The p53 tumor suppressor gene is induced rapidly following weaning of neonates, but its role in the process of involution has not been defined. Therefore, experiments were performed to identify the cell types in which the p53 gene is expressed during involution and determine the consequences of its absence in BALB/c-p53null mice. Both p53 mRNA and protein were detected in the mammary epithelium within 48 h following weaning and resulted in an eightfold increase in levels of p21WAF1 mRNA. Induction of p21WAF1 mRNA was absent in BALB/c-p53null mice, and therefore, was shown to be p53-dependent. The BALB/c-p53null mice exhibited delayed involution of the mammary epithelium, as measured by 60% greater epithelial area compared to BALB/c-p53(wt) mice through 5 days post-weaning. The delay was transient with no differences being apparent at 7 days post-weaning. Expression of the stromal protease stromelysin-1 was unaffected by the absence of p53 suggesting that stromal responses were intact. These data demonstrate that p53 participates in the first stage of involution initiated by the epithelium itself, but does not affect the second phase during which stromal proteases are induced.     

Reduction of apurinic/apyrimidinic endonuclease expression after transient global cerebral ischemia in rats: implication of the failure of DNA repair in neuronal apoptosis

BACKGROUND AND PURPOSE: To clarify the relationship between apurinic/apyrimidinic endonuclease (APE/Ref-1), a multifunctional protein in the DNA base excision repair pathway, and delayed neuronal cell death associated with apoptosis, we examined the expression of APE/Ref-1 before and after transient global ischemia in rats. METHODS: Global ischemia was induced by bilateral common carotid artery occlusion and hypotension. Expression of the APE/Ref-1 protein was evaluated by Western blot and immunohistochemical analyses. Apoptosis after global ischemia was observed by DNA electrophoresis and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining. RESULTS: Immunohistochemistry showed the nuclear expression of APE/Ref-1 in the control brains. Nuclear immunoreactivity of APE/Ref-1 was significantly decreased 2 days after 10 minutes of ischemia in the hippocampal CA1 subregion. Western blot analysis of a sample from the normal brains showed a characteristic 37-kDa band, which was reduced in the hippocampal CA1 subregion after ischemia. A significant amount of DNA fragmentation was observed at 3 days but not at 1 day after ischemia. Double staining with APE/Ref-1 and TUNEL clearly showed that the neurons that lost APE/Ref-1 immunoreactivity became TUNEL positive. CONCLUSIONS: Our data provide evidence that APE/Ref-1 decreased in hippocampal CA1 neurons after transient global ischemia and that this reduction precedes DNA fragmentation, which is destined to cause apoptosis. Our results suggest the possibility that a decrease of APE/Ref-1 activity and the failure of DNA repair may underlie the mechanism of apoptosis after transient focal ischemia.     

Inductions of 3-L-nitrotyrosine in motor neurons after transient spinal cord ischemia in rabbits

The induction and distribution of 3-L-nitrotyrosine (NO2-Tyr) were examined with HPLC and immunohistochemistry in rabbit spinal cords after 15 minutes of transient ischemia until 7 days of the reperfusion. After the 15-minute ischemia, there was a significant decrease of neurologic scores in the ischemic group compared with the sham-operated control group at 7 days of reperfusion (P = 0.0017), and the majority of motor neurons was selectively lost at 7 days of reperfusion (P = 0.0039). NO2-Tyr was transiently induced at 8 hours of reperfusion in the ventral part of the spinal cord (0.47%+/-0.86%, NO2-Tyr/total tyrosine; P = 0.0021), but was not induced at any time point of reperfusion in the dorsal part of the spinal cord. Strong immunoreactivity for NO2-Tyr was selectively induced in large pyramidal motor neurons at 8 hours of reperfusion and was still weakly present until 7 days of reperfusion. (There may be a difference in sensitivity between the two techniques.) These results suggested that protein tyrosine nitration by nitric oxide plays a role in the selective motor neuron cell damage after transient spinal cord ischemia.     

Stimulation of beta2-adrenoceptors inhibits apoptosis in rat brain after transient forebrain ischemia

We have previously demonstrated that the neuroprotective effect of the beta2-adrenoceptor agonist clenbuterol in vitro and in vivo was most likely mediated by an increased nerve growth factor (NGF) expression. In the present study, we examined whether clenbuterol was capable of inhibiting apoptosis caused by ischemia. Transient forebrain ischemia was performed in male Wistar rats (300 to 350 g) by clamping both common carotid arteries and reducing the blood pressure to 40 mm Hg for 10 minutes. Clenbuterol (0.1, 0.5, and 1.0 mg/kg intraperitoneally) was administered 3 hours before ischemia or immediately after ischemia. The brains were removed for histologic evaluation 7 days after ischemia. The time course of DNA fragmentation was determined 1, 2, 3 and 4 days after ischemia. Staining with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) was used for further analysis of DNA fragments in situ 3 days after ischemia. The NGF protein was assayed by enzyme-linked immunosorbent assay. Ten-minute forebrain ischemia damaged 80% to 90% of the neurons in the hippocampal CA1 region evaluated 7 days after ischemia. Pretreatment with clenbuterol (0.5 and 1.0 mg/kg) reduced the neuronal damage by 18.1% (P < 0.01) and 13.1% (P < 0.05), respectively. The neuroprotective effect also was found when clenbuterol (0.5 mg/kg) was administered immediately after ischemia (P < 0.05). The DNA laddering appeared in striatum 1 day and in hippocampus 2 days after ischemia and peaked on the third day in both regions. The DNA laddering was nearly abolished in the hippocampus and partially blocked in striatum and cortex by 0.5 mg/kg clenbuterol. These results were confirmed by TUNEL staining. Clenbuterol (0.5 mg/kg intraperitoneally) elevated the NGF protein level by 33% (P < 0.05) in the hippocampus and 41% (P < 0.05) in the cortex 6 hours after ischemia. Three days after ischemia, the NGF levels in these regions were no longer different between the clenbuterol-treated and control groups. This study clearly demonstrates that clenbuterol possesses a neuroprotective activity and a marked capacity to inhibit DNA degradation after global ischemia. The results suggest that clenbuterol increases NGF expression during the first hours after global ischemia and thereby protects neurons against apoptotic damage.     

Prolongation and enhancement of postischemic c-fos expression after fasting

BACKGROUND AND PURPOSE: A rapid but transient expression of c-fos after cerebral ischemia has been extensively documented. However, the mechanism of this induction and whether induction of c-fos is neuroprotective or detrimental to the brain after ischemia is presently not clear. Fasting before transient cerebral ischemia has been shown to reduce delayed neuronal necrosis and infarct volume. The purpose of the present study was to examine the effect of preischemic fasting for 24 hours on the expression of c-fos after transient focal cerebral ischemia. METHODS: Focal cerebral ischemia was induced by temporary occlusion of the right middle cerebral artery and both common carotid arteries for 60 minutes. Male Long-Evans rats weighting 250 to 300 g were randomly divided into two groups: fed (control group) and food deprived for 24 hours (fasted group) before ischemic surgery. Infarct volumes were measured on the basis of triphenyltetrazolium chloride-delineated infarct areas, and plasma glucose levels were determined by the glucose oxidase method. Temporal and spatial expression of c-fos was assessed by Northern blot analysis, in situ hybridization, and immunohistochemistry. RESULTS: Fasting for 24 hours before 60 minutes of ischemia resulted in a 26.6% decrease in preischemic plasma glucose levels and a 74.5% reduction in infarct volumes in the fasted group compared with the control group. A rapid but transient induction of c-fos mRNA was observed in the ischemic cortex in control animals after 60 minutes of ischemia. Fasting not only prolonged but also enhanced the intensity of c-fos expression in the ischemic cortex. Regional c-fos expression was also different between these two groups. CONCLUSIONS: The results support the contention that c-fos expression may be compatible with its purported neuroprotective role in selected experimental paradigms. The signaling mechanisms underlying the effect of fasting and subsequent lowering of plasma glucose levels on postischemic c-fos expression remain to be explored.     

In vivo evaluation of leukocyte dynamics in retinal ischemia reperfusion injury

PURPOSE: To evaluate quantitatively leukocyte dynamics in vivo in the rat retinal microcirculation during ischemia reperfusion injury with the use of acridine orange digital fluorography. METHODS: Retinal ischemia was induced in anesthetized pigmented rats by a temporary ligation of the optic nerve. After 60 minutes of ischemia, leukocyte behavior in the retinal microcirculation was evaluated, with acridine orange digital fluorography--consisting of a scanning laser ophthalmoscope and the fluorescent nuclear dye, acridine orange--during reperfusion at 1, 2, 4, 6, 12, 24, 48, 96, and 168 hours. The obtained images were recorded on videotape and analyzed with a computer-assisted image analysis system. RESULTS: Rolling leukocytes along the major retinal veins were observed in treated rats during the reperfusion period; no rolling leukocytes were observed in the control rats. The number of rolling leukocytes gradually increased and peaked at 102 +/- 40 cells/minute 12 hours after reperfusion; few rolling leukocytes were observed at 96 hours. The velocity of rolling leukocytes at 12 hours (19.1 +/- 3.5 microns/second; P < 0.05) was significantly lower than that at the other three times. No rolling leukocytes were observed along the arterial walls throughout the experiments. The number of accumulated leukocytes increased as time elapsed, peaked at 931 +/- 187 cells/mm2 24 hours after reperfusion, and decreased thereafter. CONCLUSIONS: Leukocyte dynamics in the retinal microcirculation can be quantitatively evaluated during ischemia reperfusion injury.     

Immunocytochemical study of retinal diode laser photocoagulation in the rat

AIM: To determine the nature of the cellular infiltrate, alterations in cell adhesion molecules, and MHC II antigen expression in the rat retina following diode laser retinal photocoagulation. METHOD: 20 normal Lister rats underwent diode laser photocoagulation of the retina. Frozen sections from eyes enucleated at 0, 1, 5, 13, and 33 days post laser were examined for T cells (R7.3), CD4 T cells (W3/25), activated CD4 T cells (OX-40), CD8 T cells (OX-8), B cells (OX-33), and macrophages (OX-42), MHC II antigen (OX-6), and E-Selectin-1, VCAM-1, and ICAM-1. RESULTS: Retinal diode laser photocoagulation stimulated a wound healing response in the outer retina and choroid. The cellular infiltrate included macrophages and activated CD4 T cells at 13 and 33 days post laser. Glial cells in the inner plexiform and inner nuclear layers expressed MHC II antigen at 24 hours only. ICAM-1 antigen was induced in RPE cells and in Muller cells in the inner retina at all time intervals post laser and intense staining for ICAM-1 was present around intraretinal migrated cells at 13 and 33 days post laser. VCAM-1 antigen expression was induced in the choroidal vascular endothelium and RPE at 13 and 33 days after laser as was E-Selectin-1 antigen expression which was also evident focally at the external limiting membrane in association with migrated cells adjacent to the burn. CONCLUSIONS: These results suggest that alterations in cell adhesion molecules may regulate the migration and activation of retinal pigment epithelium, macrophages and CD4 T cells at the outer blood-retinal barrier and choroid following diode laser photocoagulation of the normal Lister rat retina.     

Differentiation between transient ischemic attack and ischemic stroke within the first six hours after onset of symptoms by using 99mTc-ECD-SPECT

The aim of this study was to define the accuracy of 99mTc-ethyl cysteinate dimer-single photon emission computed tomography (99mTc-ECD-SPECT) in distinguishing transient ischemic attack from completed ischemic stroke at early stages after the onset of symptoms. In a prospective study we examined 82 patients within 6 hours after the onset of symptoms (neurologic deficit caused by middle cerebral artery ischemia) using both 99mTc-ECD-SPECT and computed tomography (CT). The follow-up was based on Scandinavian Stroke Scale (SSS) 24 hours and 5-7 days, as well as on CT 7 days, after the event. SPECT evaluation was performed both visually and using semiquantitative region-of-interest (ROI) analysis. According to visual SPECT analysis, on admission 59 of 82 patients had activity deficits in the symptomatic hemisphere. After 7 days, all these patients had neurologic symptoms (SSS 28 +/- 12 points), caused by a cerebral infarction as evidenced with CT. Twenty-three of 82 patients displayed no early activity deficit despite clinical symptoms. None of these patients had neurologic symptoms after 7 days (indicating transient ischemic attack or prolonged reversible ischemic neurologic deficit). In the semiquantitative SPECT analysis, all patients had abnormal count densities in the respective ROI (activity < 90% compared with the contralateral side). All patients with transient ischemia (n = 23) had count rate densities more than 70% of the respective contralateral ROI, whereas all patients with subsequent infarction (n = 59) had values < 70%. Use of 99mTc-ECD-SPECT allows transient ischemia to be distinguished from ischemic infarction using relative regional activity thresholds within the first 6 hours after onset of symptoms.     

Mechanism of the pathogenesis of glutamate neurotoxicity in retinal ischemia

PURPOSE: This study was carried out to examine the involvement of glutamate and nitric oxide neurotoxicity in ischemia/reperfusion-induced retinal injury in vivo. METHODS: We monitored glutamate release from in vivo cat retina during and after pressure-induced ischemia using a microdialysis technique. Morphometric studies were performed to study the effects of MK-801 (dizocilpine), L-NAME (N omega-nitro-L-arginine methyl ester), and D-NAME (N omega-nitro-D-arginine methyl ester) on the histological changes in the rat retina induced by ischemia or intravitreal injection of NMDA (N-methyl-D-aspartate; 200 nmol). RESULTS: A large release of glutamate occurred during ischemia, followed by a marked release after reperfusion. Histological changes occurred selectively in the inner part of the retina after ischemia as well as intravitreal injection of NMDA. Pretreatment with intravenous injection of MK-801 or L-NAME significantly inhibited the ischemic injury of the inner retina. Intravitreal injection of L-NAME inhibited NMDA-induced neurotoxicity in the retina. CONCLUSION: These findings indicate that nitric oxide mediates neurotoxic actions of glutamate which are responsible for ischemic injury in the retina.     

Survey of nurse anesthesia practice, education, and regulation in 96 countries

Reconstitution of the p53-dependent apoptotic pathway by gene transfer of a recombinant wild-type p53 minigene leads to rapid apoptotic cell death in breast and other cancer cell types expressing null or mutant p53. Tumour cells expressing wild-type p53 have been reported to be more resistant to this treatment strategy, presumably as a result of mutations in downstream regulators of p53-dependent apoptotic signalling. The MCF-7 breast cancer cell line is representative of this class of tumour cell. Our recent observation of a p53-dependent apoptotic response following adenovirus-mediated HSV thymidine kinase gene transfer and gancyclovir treatment led us to reexamine recombinant p53 cytotoxicity in MCF-7 cells. Infection with a recombinant adenovirus expressing wild-type p53 resulted in a dramatic increase in p53 protein levels and was accompanied by an increase in p21WAF/CIP1 protein levels and G1 arrest within 24 hours post-infection. A significant decrease in MCF-7 cell viability was first observed at 5 days post-infection and coincided with the appearance of morphological and biochemical changes consistent with apoptotic cell death. By day 7 post-treatment, cell viability decreased to 45% and clonogenic survival was reduced to 12% of controls. The results demonstrate that persistent, high level expression of recombinant p53 can induce programmed cell death in MCF-7 cells. While the mechanism by which p53 overexpression overcomes the defect in downstream apoptotic signalling is not clear, our data suggests that this treatment strategy may be beneficial for the class of tumour cells represented by the MCF-7 cell line.     

Long-lasting neuroprotective effect of postischemic hypothermia and treatment with an anti-inflammatory/antipyretic drug. Evidence for chronic encephalopathic processes following ischemia

BACKGROUND AND PURPOSE: It has been recognized that postischemic pharmacological interventions may delay the evolution of neuronal damage rather than provide long-lasting neuroprotection. Also, fever complicates recovery after stroke in humans. Here we report the effects of late postischemic treatment with hypothermia and an antipyretic/anti-inflammatory drug, dipyrone, on cell damage at 1 week and 2 months of survival. METHODS: Rats were subjected to 10 minutes of forebrain ischemia. Hypothermia (33 degrees C) was induced at 2 hours of recovery and maintained for 7 hours. Dipyrone (100 mg.kg-1IP) was given every 3 hours from 14 to 72 hours of recovery. Temperature was measured every 6 hours for 60 days. Neuronal damage was assessed at 7 days and 2 months of recovery. RESULTS: From 17 to 72 hours of recovery, a period of hyperthermia was observed, which dipyrone abolished but postischemic hypothermia treatment did not. Dipyrone treatment diminished neuronal damage by 43% at 7 days, and at 2 months of survival, a minor (16%) protection was seen. Postischemic hypothermia treatment alone delayed neuronal damage. In contrast, combined treatment of hypothermia followed by dipyrone markedly diminished neuronal damage by more than 50% at both 7 days and 2 months of recovery. CONCLUSIONS: Neuronal degeneration may be ongoing for months after a transient ischemic insult, and prolonged protective measures need to be instituted for long-lasting neuroprotective effects. Hyperthermia during recovery worsens ischemic damage, and processes associated with inflammation may contribute to the development of neuronal damage. An early and extended period of postischemic hypothermia provides a powerful and long-lasting protection if followed by treatment with anti-inflammatory/ antipyretic drug.     

The ecological cause of the higher accumulation of 90Sr and 137Cs in the food of northern inhabitants

PURPOSE: To quantify S-antigen-specific (S-Ag) T cells in the retina after adoptive transfer, and to evaluate their role in the initiation and progress of destructive ocular inflammation in experimental autoimmune uveoretinitis (EAU). METHODS: Lewis rats were administered 10 x 10(6) S-Ag-specific T cells from the SP35 cell line or 10 x 10(6) concanavalin A-stimulated syngeneic spleen cell lymphoblasts labeled with lipophilic PKH26 fluorescent dye immediately before intravenous inoculation. Labeled cells in each retina were counted at various times from 4 to 120 hours after cell transfer by fluorescence microscopic analysis of each dissociated retina. Recipient eyes were examined within the same period by light and confocal microscope. RESULTS: SP35 T cells showed a biphasic distribution in the retina. The first peak of 160 cells/retina was noted at 24 hours. A steady decline of labeled cells at 48 and 72 hours was followed by a rapid increase at 96 and 120 hours. Concanavalin A-stimulated, control-labeled cell populations showed an identical peak at 24 hours but a persistent decline thereafter; only two or three T cells were present in each retina at 120 hours. Concurrent inoculation of SP35 cells and nonspecific T cell blasts did not produce more SP35 cells than control cells in the retina at any time. Microscopic analysis showed mononuclear cell infiltration of the iris, ciliary body, and aqueous humor at 48 hours, which intensified rapidly and persisted through 120 hours. Retinal inflammation did not begin until 80 hours. Mononuclear cell adherence to vascular endothelium and perivascular macrophage infiltration of the innermost layers progressed to edema, and profound destructive inflammation and loss of retinal stratification were observed at 120 hours. CONCLUSIONS: There is no evidence of a blood-ocular or blood-retinal barrier to activated T cell blasts. Autologous S-Ag does not provoke a more rapid entry of specific T cells at that site. The data confirm that anterior segment inflammation precedes retinal inflammation, even though S-Ag-specific T cells were present in the retina within a few hours after cell transfer. Because S-Ag is clearly present in the retina, delay in antigen presentation at that site may account for the temporal difference between retinal and anterior segment inflammation.