Quantitative assessment of cardiac myocyte apoptosis in tissue sections using the fluorescence-based tunel technique enhanced with counterstains

Apoptosis is a distinct form of cell death, induced, for example, by ischaemia/reperfusion injury, that results in characteristic alterations in cell morphology and fate. In tissue sections, the most commonly used technique to detect apoptosis is terminal deoxynucleotidyl transferase mediated nick end labelling (TUNEL) staining which labels the ends of DNA strand breaks characteristic of the apoptotic process. However, without the employment of additional staining, TUNEL is only a qualitative procedure that gives no information about the proportion of negative cells nor the cell type undergoing apoptosis. We have utilised propidium iodide (PI) as a counterstain to visualise TUNEL negative nuclei together with anti-desmin antibody in order to assess quantitatively apoptosis in specific cell types. The procedure has been evaluated in tissue sections from isolated perfused rat hearts subjected to ischaemia and reperfusion. Hearts were cross-sectioned into four 2.5 mm thick slices which were fixed in 4% formaldehyde and embedded in paraffin. Serial sections (5 microns) were cut, dewaxed and pretreated by incubation with trypsin at 37 degrees C for 30 min. After the employment of the TUNEL assay, sections were labelled with anti-desmin antibody, counterstained with PI and finally examined by confocal fluorescent microscopy. Apoptosis was not seen in sections from hearts subjected to ischaemia alone nor in control hearts. After 35 min of ischaemia the percentages of TUNEL positive cells were very low both in myocytes (0.1%) and in non-myocytes (0.3%). In ischaemic-reperfused hearts, the number of TUNEL positive cells was only significantly higher in vascular cells (44+/-5%) and cardiac myocytes (6+/-2%). This simple method therefore allows quantification of apoptosis in myocytic and non-myocytic cells in tissue sections. Use of alternative immunohistochemical markers would permit adaptation of the method to the quantitative assessment of apoptosis in other tissues.

Identification of cerebral ischemic lesions in rat using Eigenimage filtered magnetic resonance imaging

An accurate noninvasive time-independent identification of an ischemic cerebral lesion is an important objective of magnetic resonance imaging (MRI). This study describes a novel application of a multiparameter MRI analysis algorithm, the Eigenimage (EI) filter, to experimental stroke. The EI is a linear filter that maximizes the projection of a desired tissue (ischemic tissue) while it minimizes the projection of undesired tissues (nonischemic tissue) onto a composite image called an eigenimage. Rats (n=26) were subjected to permanent middle cerebral artery occlusion. T2- and T1-weighted coronal MRI were acquired on separate groups of animals. The animals were immediately sacrificed after each imaging session for histopathological analysis of tissue at 4-8 h, 16-24 h, and 48-168 h after stroke onset. Lesion areas from MRI were defined using EI. The EI defined lesion areas were coregistered and warped to the corresponding histopathological sections. The ischemic lesion as defined by EI exhibited ischemic cell damage ranging from scattered acute cell damage to pan necrosis. Ischemic cellular damage was not detected in homologous contralateral hemisphere regions. EI lesion areas overlaid on histopathological sections were significantly correlated (r=0.92, p<0.05) acutely, (r=0.98, p<0.05) subacutely, and (r=0.99, p<0.05) chronically. These data indicate that EI methodology can accurately segment ischemic damage after MCA occlusion from 4-168 h after stroke.

Registration and warping of magnetic resonance images to histological sections

We present a method for coregistration and warping of magnetic resonance images (MRI) to histological sections for comparison purposes. This methodology consists of a modified head and hat surface-based registration algorithm followed by a new automated warping approach using nonlinear thin plate splines to compensate for distortions between the data sets. To test the methodology, 15 male Wistar rats were subjected to focal cerebral ischemia via permanent occlusion of the middle cerebral artery. The MRI images were acquired in separate groups of animals at 16-24 h (n = 9) and 48-168 h (n = 6) postocclusion. After imaging, animals were immediately sacrificed and hematoxylin- and eosin-stained brain sections were obtained for histological analysis. The MRI was coregistered and warped to histological sections. The MRI lesion areas were defined using the Eigenimage (EI) filter technique. The EI is a linear filter that maximizes the projection of a desired tissue (ischemic tissue) while it minimizes the projection of undesired tissues (nonischemic tissue) onto a composite image called an EI. When using coregistration without warping the MRI lesion area demonstrated poor correlation (r = 0.55, p > 0.01) with a percent difference between the two lesion areas of 22.5% +/- 10.8%. After warping, the MRI and histology had significant correlation (r = 0.97, p < 0.01) and a decreased percent difference of 5.56% +/- 4.31%. This methodology is simple and robust for coregistration and warping of MRI to histological sections and can be utilized in many applications for comparison of MRI to histological data.

MR imaging of human brain at 3.0 T: preliminary report on transverse relaxation rates and relation to estimated iron content

PURPOSE

To determine the transverse relaxation rates R2 and R2' from several gray matter regions and from frontal cortical white matter in healthy human brains in vivo and to determine the relationship between relaxation rates and iron concentration [Fe].

MATERIALS AND METHODS

Six healthy adults aged 19-42 years underwent thin-section gradient-echo sampling of free induction decay and echo magnetic resonance (MR) imaging at 3.0 T. Imaging covered the mesencephalon and basal ganglia.

RESULTS

Relaxation rates (mean +/- SD) were highest in globus pallidus (R2 = 25.8 seconds-1 +/- 1.1, R2' = 12.0 seconds-1 +/- 2.1) and lowest in prefrontal cortex (R2 = 14.4 seconds-1 +/- 1.8, R2' = 3.4 seconds-1 +/- 1.1). Frontal white matter measurements were as follows: R2 = 18.0 seconds-1 +/- 1.2 and R2' = 3.9 seconds-1 +/- 1.2. For gray matter, both R2 and R2' showed a strong correlation (r = 0.92, P < .001 and r = 0.90, P < .001, respectively) with [Fe]. Although the slopes of the regression lines for R2' versus [Fe] and for R2 versus [Fe] were similar, the iron-independent component of R2' (2.2 seconds-1 +/- 0.6), the value when [Fe] = 0, was much less than that of R2 (12.7 seconds-1 +/- 0.7).

CONCLUSION

The small iron-independent component R2', as compared with that of R2, is consistent with the hypothesis that R2' has higher iron-related specificity.

Th2 cytokines exert a dominant influence on epithelial cell expression of the major group human rhinovirus receptor, ICAM-1

Intercellular adhesion molecule (ICAM)-1 is a cell receptor important in both human rhinovirus (HRV) attachment and immune effector cell mobilization. The level of expression of ICAM-1 by epithelial cells (EC) therefore plays a crucial role in the intricate biological phenomena underlying viral binding, host infection and consequent inflammatory events. As T-helper (Th)2 lymphocytes predominate within the asthmatic airway, the influence was evaluated of Th2-associated mediators in the modulation of ICAM-1 expression on uninfected and HRV-infected EC. H292 EC were cultured in vitro, with varying concentrations of interleukin (IL)-4, IL-5, IL-10 and IL-13 for 24 h and then infected with live HRV-14. Surface ICAM-1 expression was assessed by immunocytochemistry. Infection with HRV-14 resulted in a twofold increase in ICAM-1 expression. IL-4, IL-5, IL-10 and IL-13 produced a 2.7-5.1-fold enhancement of ICAM-1 expression of uninfected cells and caused approximately a further twofold increase in infected cells over the expression induced by HRV infection itself. Interferon-gamma in combination with each Th2-associated cytokine only slightly reduced, but did not override, the Th2-induced level of ICAM-1 expression on both uninfected and virus-infected EC. These data suggest that the effects of Th2-associated cytokines on intercellular adhesion molecule-1 expression and recovery of infectious virus are dominant over the effects of the Th1-associated cytokines such as interferon-gamma. Since the airway mucosa in atopic asthma is predominantly infiltrated by Th2 lymphocytes, these results could explain both the increased susceptibility to human rhinovirus infection in asthmatic patients and the associated exacerbation of asthma symptoms.

Expression of insulin-like growth factor binding proteins in bronchoalveolar lavage fluid of patients with pulmonary sarcoidosis

Pulmonary sarcoidosis involves development of parenchymal granulomata that usually resolve spontaneously; however, it remains unclear what pathogenic mechanisms are responsible for the progression to local or diffuse fibrosis with irreversible lung remodeling that occurs in 20% of patients. Alveolar macrophages have a pivotal role in sarcoidosis, releasing mediators including insulin-like growth factor (IGF)-1, a potent profibrogenic molecule. IGF-1 bioavailability in the lung is dependent on at least six high-affinity IGF-binding proteins (IGFBP), which mainly inhibit IGF-1 action. We have investigated their presence in patients with established stage III sarcoidosis to determine whether IGF-1 and IGFBP contribute to the fibrogenic process in these patients and as such contribute to the (clinical) progression of the disease. The fibroblast mitogenic potential of bronchoalveolar lavage fluid (BALF) was more than 3-fold higher (P < 0.005) in sarcoid patients. Sarcoid BALF-induced activity could be inhibited (P < 0.0005) by neutralizing antibodies to IGF-1. We established the IGFBP profile of BALF with Western ligand analysis and quantified expression of IGFBP-3 by immunoblotting. IGFBP-2 and IGFBP-4 predominate in normal and sarcoid BALF, but IGFBP-3 occurs only as a modified, smaller, 29-kD form, expression of which was raised (P < 0.003) in sarcoid patients. Gene expression of IGF-1 and IGFBP-3 was demonstrated by reverse transcription-polymerase chain reaction in BAL cells. Thus, local production of pro-fibrogenic IGF-1 may be subject to substantial post-translational regulation by associated IGFBP and IGFBP proteases that may contribute to enhanced fibrogenesis in sarcoidosis patients with evidence of progression or (development) of fibrosis.

Sequential identification of apoptotic and necrotic cells on individual cytospin preparations

Here, we describe a simple methodology which allows the consecutive differentiation of apoptotic and necrotic cells on the same cytospin preparation of fresh and cultured cells. In this methodology, necrotic cells are initially identified on the cytospin preparations using trypan blue followed by the identification of in situ DNA fragmentation using the TUNEL assay. Identification of trypan blue and TUNEL positive cells in the same section permits the simultaneous assessment of necrotic and apoptotic cells.

Preliminary clinical-radiological assessment of a MR tissue signature model in human stroke

We evaluated the ability of an MR signature model (SM) of cerebral ischemic injury to stage the evolution of cellular damage in human stroke. In 19 patients with ischemic stroke of presumed embolic or non-embolic cause we carried out diffusion-weighted and T2-weighted MR imaging within 48 h of onset, and obtained apparent diffusion coefficient of water (ADCw), and T2 weighted images. We used the signatures obtained from these ADCw/T2 maps to formulate two patterns of damage signifying accelerated or non-accelerated progression of cellular death after stroke onset. Those patients with the accelerated pattern corresponded to those with the neuroradiological (NRC) and clinical diagnosis (TOAST.1 and TOAST.2) of presumed embolic stroke, with clinical diagnosis performed blinded both to NRC and to SM. Agreement between the SM and NRC was substantial (kappa=0.62), moderate (0.60<kappa<0.40) between the SM or NRC and TOAST.2, and fair (0.40<kappa<0.20) among the SM or NRC and TOAST.1. We believe these results constitute a preliminary validation of the MR tissue signature modeling in clinical stroke assessment.

Expression and protective effects of urocortin in cardiac myocytes

Reverse transcription PCR showed that mRNA encoding the CRH-like molecule, urocortin, is expressed in a rat cardiac myocyte cell line and in primary cultures of cardiac myocytes. Identity of the amplified with the published sequence was established by restriction mapping and direct sequencing. Expression of urocortin mRNA was increased 12-18 h after thermal injury. Urocortin peptide protected cardiac myocytes from cell death induced by hypoxia. The data suggest that urocortin is an endogenous cardiac myocyte peptide which modulates the cellular response to stress.

Prediction of impending hemorrhagic transformation in ischemic stroke using magnetic resonance imaging in rats

BACKGROUND AND PURPOSE

Hemorrhagic transformation (HT) of ischemic brain tissue may occur in stroke patients either spontaneously or after thrombolysis. A method to assess the risk of HT in ischemic tissue after stroke would improve the safety of thrombolytic therapy. As a means of predicting HT, we investigated the role of contrast-enhanced MRI at acute time points in a rat middle cerebral artery occlusion model with reperfusion.

METHODS

Intraluminal suture occlusion of the middle cerebral artery was used to produce transient ischemia in male Wistar rats (n=11). Reperfusion was performed by withdrawal of the occluding filament after 2 (n=4), 3 (n=6), or 4 (n=1) hours. MRI studies were performed before and after reperfusion with the use of conventional T1-weighted imaging, with and without gadolinium (Gd-DTPA) contrast agent, and T2-weighted imaging. Follow-up MRI and histological studies were obtained at 24 hours.

RESULTS

Petechial hemorrhage occurred by 24 hours in 9 of 11 animals. All animals showed brain swelling and cellular death throughout the ischemic region at 24 hours. A hyperintense region in the preoptic area became visible after Gd-DTPA injection within minutes after reperfusion in animals with subsequent HT. All animals showing acute Gd-DTPA enhancement subsequently developed petechial hemorrhage (or died) by 24 hours. In these animals, statistically significant differences in signal intensity (P=.0005) between the ipsilateral enhancing region and a homologous contralateral region were detected on post-Gd-DTPA T1-weighted imaging. There was also a statistically significant correlation (P=.01) between the rate of Gd-DTPA uptake and the size of the enhancing area. Two animals did not enhance with Gd-DTPA and did not exhibit hemorrhage on histological examination or MRI at 24 hours. No abnormalities were seen on precontrast T1-weighted images before and shortly after reperfusion or postcontrast T1-weighted images before reperfusion.

CONCLUSIONS

The primary finding of this study was the detection of early Gd-DTPA parenchymal enhancement in 82% of the animals after reperfusion. Enhancement was seen before any detectable hemorrhage, suggesting that early endothelial ischemic damage occurs before gross brain infarction and hemorrhage. Thus, we suggest that acute Gd-DTPA enhancement may provide an early prediction of petechial hemorrhage.

Interferon-gamma (IFN-gamma) down-regulates the rhinovirus-induced expression of intercellular adhesion molecule-1 (ICAM-1) on human airway epithelial cells

Human rhinoviruses (HRV) are a major cause of upper respiratory tract infections in man, and can exacerbate existing pulmonary disease. The major group of HRV attach to ICAM-1, which is expressed on nasal and bronchial epithelial cells. To study the influence of biological mediators on ICAM-1 expression, and consequently HRV attachment and infection, we compared the effects of various cytokines, alone and in combination, on ICAM-1 expression by an uninfected and HRV-infected bronchial epithelial cell line H292. Cytokines known to be released soon after viral infection, such as tumour necrosis factor-alpha (TNF-alpha), IL-1beta and the chemokine IL-8 increase ICAM-1 expression on uninfected cells. Epithelial cells infected with live HRV-14 displayed marked up-regulation of ICAM-1 compared with baseline. TNF-alpha further enhanced the HRV-induced increase in ICAM-1 expression on epithelial cells, peaking at day 4 after infection, whilst IL-8 exhibited a steady increase in ICAM-1 expression over 14 days. In contrast, IFN-gamma, a known Th1 antiviral lymphokine, whilst increasing the level of ICAM-1 on uninfected cells, induced a significant persistent down-regulation of ICAM-1 expression on HRV-infected epithelial cells. With combinations of TNF-alpha and IFN-gamma, ICAM-1 expression on HRV-infected cells was reduced to basal levels. The effects of IFN-gamma were paralleled by a reduction in viral titres. Our in vitro model has provided useful insights into the early pathogenic events of HRV infection at the level of the host cell-virus interaction. Our data confirm that biological mediators play a crucial role in the pathogenesis as well as the course of HRV infection which is modulated by the types, and time kinetics of inflammatory cytokines in the immediate microenvironment.

Recidivism rates among child molesters and rapists: a methodological analysis

We address the high variability in sex offender recidivism rates by examining several of the critical methodological differences that underlie this variability. We used a dataset on 251 sex offenders (136 rapists and 115 child molesters) who were discharged over a 25-year period to examine changes in recidivism as a function of changes in dispositional definition of reoffense (e.g., arrest or conviction), changes in the domain of criminal offenses that are considered, and changes in the length of exposure time. The data indicate that: (a) both rapists and child molesters remain at risk to reoffend long after their discharge, in some cases 15-20 years after discharge; (b) there was a marked underestimation of recidivism when calculating a simple proportion (%) consisting of those who were known to have reoffended during the follow-up period, and (c) there was a marked underestimation of recidivism when the criterion was based on conviction or imprisonment. Forensic, clinical and policy implications of this high variability are discussed.

C/EBP activates the human corticotropin-releasing hormone gene promoter

The purpose of these studies was to identify whether transcription factors, associated with cytokine signalling, affected promoter activity of the corticotropin releasing hormone (CRH) gene. Fragments of a 3.6 kb sequence of the human CRH gene promoter were amplified by PCR and ligated upstream of a CAT reporter. These constructs were transfected into a variety of cell lines, either alone or together, with transcription factor expression vectors. Basal activity of a 3070 bp CRH promoter fragment was only seen in neuronal and lymphoblastoid cell lines. Promoter activity was increased by the transcription factors C/EBPbeta (NF-IL6) and more strongly, by C/EBPdelta (NF-IL6beta). Increased CRH promoter activity following phorbol ester treatment was inhibited by a dominant negative NF-IL6 mutant, showing that the effects of phorbol ester were principally mediated by C/EBP. Moreover, the inverse changes in the expression of CRH in the hypothalamus and spleens of arthritic rats were paralleled by similar inverse changes in NF-IL6beta expression in these organs. These data show that some transcription factors associated with cytokine signalling can also activate the CRH promoter.

Mitogenic response and steroid sensitivity in MS lymphocytes

OBJECTIVES

We investigated mitogenic response and steroid sensitivity in multiple sclerosis (MS) lymphocytes to establish if MS lymphocytes were less steroid responsive.

MATERIAL AND METHODS

We compared mitogenic response to phytohaemagglutinin (PHA) and inhibition by dexamethasone (DEX) in circulating lymphocytes from both MS patients and healthy subjects.

RESULTS

We found a range of responses in each group but no significant differences between the two groups, nor in patients with and without enhancement on magnetic resonance imaging. The mid-inhibitory concentration of DEX in response to 1 microg/ml PHA was significantly lower than that for 2.5 microg/ml PHA in the patients. The mid-inhibitory concentrations of DEX in response to 2.5 microg/ml PHA negatively correlated with endogenous serum cortisol concentrations.

CONCLUSION

These data imply a spectrum of glucocorticoid response that is similar in normal and MS lymphocytes and can partly explain why response to steroid therapy is variable.

Defective antigen presentation by lavage cells from terminal patients with cystic fibrosis

Macrophages separated from lavage samples obtained from lungs removed at transplantation from patients with cystic fibrosis (CF) and other lung diseases, have been compared with circulating monocytes from the same patients for their ability to stimulate allogeneic normal circulating lymphocytes and to present antigen to autologous hilar lymph node cells. In general, macrophages separated from lavage samples from CF patients were unable to stimulate allogeneic lymphocytes and to present antigen, although monocytes from the same patients were functional in both assays. In contrast, lavage cells from non-CF patients were generally effective in both allogeneic stimulation and antigen presentation. These data suggest that immune cells within the lungs of CF patients are functionally compromised, a deficiency which may contribute to the recurrent infections characteristic of the disease.

Risk factors associated with recidivism among extrafamilial child molesters

This study examined the predictive efficacy of 10 rationally derived, archivally coded variables for assessing reoffense risk among extrafamilial child molesters. Follow-up data on 111 child molesters who were discharged from the Massachusetts Treatment Center between 1960 and 1984 were used. Degree of sexual preoccupation with children, paraphilias, and number of prior sexual offenses predicted sexual recidivism. Juvenile and adult antisocial behavior, paraphilias, and low amount of contact with children predicted nonsexual victim-involved and violent recidivism. Area under the receiver-operating characteristic curves in all three analyses indicated discrimination that was substantially better than chance, ranging from .73 to .79.

Reduced top-down influence in auditory perceptual organization in schizophrenia

Perceptual organization of auditory information is influenced by both the physical characteristics and the categorization of irrelevant information. This study sought to determine the degree to which schizophrenia patients could utilize acoustic properties and contextual cues (top-down factors) to segregate relevant from irrelevant material in an auditory stream. On a modification of I. Neath, A. M. Surprenant, and R. G. Crowder's (1993) auditory suffix task, both schizophrenia and control participants demonstrated better recall of relevant information when irrelevant information had different physical characteristics, compared with when both arose from the same source. In contrast, schizophrenia patients were unaffected by a contextual manipulation that allowed controls to reduce the interfering effect of an irrelevant stimulus. These data suggest that a reduced ability to utilize contextual information plays a role in the perceptual organization dysfunction in schizophrenia.

A possible growth factor role of IL-6 in neuroectodermal tumours

Preliminary data have shown that IL-6 may act as an autocrine growth factor to control proliferation. We further characterised the role of IL-6 in tumour growth as an autocrine/paracrine growth factor in neuroectodermal tumours. We evaluated the production and secretion of IL-6 by seven human melanoma, five neuroblastoma and one glioblastoma cell lines. Moreover, we determined their IL-6-dependent growth in serum free-medium or under minimal growth-supplement conditions: IL-6 dependent growth was observed in two non-IL-6 producing melanoma and in one neuroblastoma cell lines. In addition, expression of IL-6 mRNA and peptide was increased by retinoic acid. The data support the hypothesis that IL-6 contributes to neuroectodermal tumour growth, even though it shows a less potent effect than other reported growth factor such as IGF-II.

Retinoids and the control of growth/death decisions in human neuroblastoma cell lines

Cell proliferation, the balance between mitosis and apoptosis is the result of the continuous integration of a number of different signal transduction pathways stimulated in a cell at any given point in its life. Neuroblastoma cells regulate the switch between mitosis and death, according both to intrinsic factors and extrinsic factors, such as growth factor withdrawal and action of the vitamin A derivative, retinoic acid. In this review, we describe the balance of some factors regulating growth and death of human neuroblastoma cells in vitro. These dynamic studies are necessarily-performed on cell lines, which offer controlled conditions enabling the disection of the complex stimuli mediating survival and growth (IGF, trk, BDNF) and death (transglutaminase, free radicals, Bcl-2). Although the conclusions drawn may therefore not be directly applicable to tumour cells in vivo, the results herein discussed are of sufficient significance to warrant in vivo relevance.

The temporal evolution of MRI tissue signatures after transient middle cerebral artery occlusion in rat

We have developed a multiparameter magnetic resonance imaging (MRI) cluster analysis model of acute ischemic stroke using T2 relaxation times and the diffusion coefficient of water (ADCw). To test the ability of this model to predict cerebral infarction, male Wistar rats (n = 7) were subjected to 2 h of transient middle cerebral artery (MCA) occlusion, and diffusion and T2 weighted MRI were performed on these rats before, during and up to 7 days after MCA occlusion. MRI tissue signatures, specified by values of ADCw and T2 were assigned to tissue histopathology. Significant correlations were obtained between MRI signatures at different time points and histopathologic measurements of lesion area obtained at 1 week. In addition, we compared the temporal evolution of MRI tissue signatures to a separate population of animals at which histological data were obtained at select times of reperfusion. A significant shift (p < or = 0.05) within signatures reflecting tissue histopathology was demonstrated as the ischemic lesion evolved over time. Our data suggest, that the MRI signatures are associated with the degree of ischemic cell damage. Thus, the tissue signature model may provide a noninvasive means to monitor the evolution of ischemic cell damage and to predict final outcome of ischemic cell damage.

The prototypal view of diagnosis: predictive validity of diagnostic certainty for schizophrenia

Certainty of diagnosis in relation to several measures of predictive validity (outcome ratings) for 93 male VA psychiatric inpatients was correlated significantly for outcome measures reflecting greater long-term severity than for a more homogeneous subgroup of patients.

Reduced top-down influence in auditory perceptual organization in schizophrenia

Perceptual organization of auditory information is influenced by both the physical characteristics and the categorization of irrelevant information. This study sought to determine the degree to which schizophrenia patients could utilize acoustic properties and contextual cues (top-down factors) to segregate relevant from irrelevant material in an auditory stream. On a modification of I. Neath, A. M. Surprenant, and R. G. Crowder's (1993) auditory suffix task, both schizophrenia and control participants demonstrated better recall of relevant information when irrelevant information had different physical characteristics, compared with when both arose from the same source. In contrast, schizophrenia patients were unaffected by a contextual manipulation that allowed controls to reduce the interfering effect of an irrelevant stimulus. These data suggest that a reduced ability to utilize contextual information plays a role in the perceptual organization dysfunction in schizophrenia.