Countering health threats by chemicals with a potential terrorist background--creating a rapid alert system for Europe

BACKGROUND

The acronym "ASHT" stands for "Alerting System and Development of a Health Surveillance System for the Deliberate Release of Chemicals by Terrorists". Imagine this scenario: 15 patients with respiratory symptoms following a concert in Rome and 12 patients coughing after lunch in a cafeteria in the Czech Republic; are these events related? Today these events would never be connected as there is no mechanism to allow EU Member States to share this type of information effectively. The main objective of the ASHT project was to improve data sharing between EU Member States. In part, this was achieved by an internet accessible EU-wide alerting system with the aim to detect the deliberate (i.e. criminal or terrorist) or accidental release of chemicals. Nevertheless more information from police, fire brigades and health professionals is needed.

METHODS

Description of the design, development, functionality and testing of the relational database system called "RAS-CHEM" (Rapid Alert System for Chemicals).

RESULTS

A database structure appropriate for the description of "events" with sophisticated retrieval functions was developed. For evaluation purposes 37 events were entered into the database including 29 scenarios and 8 historical mass intoxications. The alert level was "background information" for 21 events, "suspected mass intoxication" for 6 cases and "confirmed mass intoxication" for 10 events.

CONCLUSION

The RAS-CHEM database works and will be integrated into the Health Emergency Operations Facility (HEOF) with other European Rapid Alert Systems. Poisons centres receive a large number of enquiries and could be important sentinels in this field of toxicovigilance.

Selective killing of ATM- or p53-deficient cancer cells through inhibition of ATR

Here we report a comprehensive biological characterization of a potent and selective small-molecule inhibitor of the DNA damage response (DDR) kinase ATR. We show a profound synthetic lethal interaction between ATR and the ATM-p53 tumor suppressor pathway in cells treated with DNA-damaging agents and establish ATR inhibition as a way to transform the outcome for patients with cancer treated with ionizing radiation or genotoxic drugs.

Colorectal cancer: texture analysis of portal phase hepatic CT images as a potential marker of survival

PURPOSE

To assess the utility of texture analysis of liver computed tomographic (CT) images by determining the effect of acquisition parameters on texture and by comparing the abilities of texture analysis and hepatic perfusion CT to help predict survival for patients with colorectal cancer.

MATERIALS AND METHODS

The study comprised a phantom test and a clinical evaluation of 48 patients with colorectal cancer who had consented to retrospective analysis of hepatic perfusion CT data acquired during a research study approved by the institutional review board. Both components involved texture analysis to quantify the relative contribution of CT features between 2 and 12 pixels wide to overall image brightness and uniformity. The effect of acquisition factors on texture was assessed on CT images of a cylindric phantom filled with water obtained by using tube currents between 100 and 250 mAs and voltages between 80 and 140 kVp. Texture on apparently normal portal phase CT images of the liver and hepatic perfusion parameters were related to patient survival by using Kaplan-Meier survival analysis.

RESULTS

A texture parameter that compared the uniformity of distribution of CT image features 10 and 12 pixels wide exhibited the least variability with CT acquisition parameters (maximum coefficient of variation, 2.6%) and was the best predictor of patient survival (P < .005). There was no significant association between survival and hepatic perfusion parameters.

CONCLUSION

The study provides preliminary evidence that analysis of liver texture on portal phase CT images is potentially a superior predictor of survival for patients with colorectal cancer than CT perfusion imaging.

SUPPLEMENTAL MATERIAL

http://radiology.rsnajnls.org/cgi/content/full/2502071879/DC1.

Proteomic analysis of the mouse mammary gland is a powerful tool to identify novel proteins that are differentially expressed during mammary development

After lactation, the mouse mammary gland undergoes apoptosis and tissue remodelling as the gland reverts to its prepregnant state. This complex change was investigated using 2-DE. An integrated database was produced from lactation and involution proteomes. Forty-four molecular cluster indexes (MCIs) that showed altered expression from lactation to involution were selected for MS analysis. Of these, 32 gave protein annotations, 18 of which were unequivocal proteins. Selected proteins were then studied across all of development, including pregnancy, using data integrated from another proteome database. Two proteins, the RNA polymerase B transcription factor 3 (BTF3) and the minichromosome maintenance protein 3 (MCM3), although initially selected on the basis of the lactation/involution criteria, had expression profiles that indicated an additional role in mammary development and were further analysed. BTF3, a transcription factor previously not described in the mammary gland, was up-regulated strongly in pregnancy, indicating an involvement in alveolar growth. MCM3's expression was greatest in pregnancy and late involution, decreasing through lactation. Immunohistochemistry localised MCM3 to the mammary epithelium, where a greater proportion of cells stained than for the proliferation marker Ki67. MCM3 expression during lactation may identify cells that are licensed to repopulate the gland during cell loss in lactation and following involution.

Blood flow–metabolic relationships are dependent on tumour size in non-small cell lung cancer: a study using quantitative contrast-enhanced computer tomography and positron emission tomography

PURPOSE

The purpose of this study was to undertake dual assessment of tumour blood flow and glucose metabolism in non-small cell lung cancer (NSCLC) using contrast-enhanced computed tomography (CE-CT) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in order to assess how the relationships between these parameters vary with tumour size and stage.

METHODS

Tumour blood flow and glucose metabolism were assessed in 18 NSCLCs using quantitative CE-CT and FDG-PET respectively. Contrast enhancement and FDG uptake were both normalised to injected dose and patient weight to yield correspondingly the standardised perfusion value (SPV) and standardised uptake value (SUV). Tumour area was measured from conventional CT images.

RESULTS

The ratio of SUV to SVP and the metabolic-flow difference (SUV-SVP) correlated with tumour size (r=0.56, p=0.015 and r=0.60 and p=0.008 respectively). A metabolic-flow difference of greater than 4 was more common amongst tumours of stages III and IV (odds ratio 10.5; 95% confidence limits 0.24-32.1). A significant correlation between SUV and SPV was found only for tumours smaller than 4.5 cm2 (r=0.85, p=0.03).

CONCLUSION

Blood flow-metabolic relationships are not consistent in NSCLC but depend upon tumour size and stage. Quantitative CE-CT as an adjunct to an FDG study undertaken using integrated PET-CT offers an efficient way to augment the assessment of tumour biology with possible future application as part of clinical care.

Proteomic analysis of mouse mammary terminal end buds identifies axonal growth cone proteins

Ductal morphogenesis in the mouse mammary gland occurs mainly postnatally and is driven by specialized structures at the ends of the developing ducts, the terminal end buds (TEBs), which later regress once ductal growth is complete. To identify proteins that are specifically associated with migration of TEBs we developed a novel method of isolating TEBs, which eliminated the mammary stroma. The protein expression profile of the TEBs was then compared with that of isolates taken from the 4th inguinal mammary gland of adult virgin mice using two-dimensional (2-D) gel electrophoresis and mass spectrometry (MS) analysis (matrix-assisted laser desorption/ionization and quadrupole time of flight). Following construction of an integrated protein expression database, 44 protein features which showed differential expression levels between the two sets were chosen for MS analysis. Of these, 24 gave protein annotations whereas the other 20 produced unidentified peptides. Fourteen unequivocal proteins were identified from these 24, whereas the remaining 10 matched more than one protein within a single 2-D gel feature. Several of the identified proteins were associated with the cytoskeleton and have previously been reported in axonal growth cones, suggesting that they may influence cell shape and motility within the advancing TEBs, in a similar fashion to migrating axons.

Proteome analysis of adipogenesis

Adipose tissue plays a crucial endocrine role in controlling whole body glucose homeostasis and insulin sensitivity. Given the substantial rise in obesity and obesity-related diseases such as diabetes, it is important to understand the molecular basis of adipocyte differentiation and its control. Many studies have successfully exploited gene array technology to monitor changes in the profile of expressed genes during adipocyte differentiation, although this method only measures changes at the level of individual mRNA species. Using two-dimensional polyacrylamide gel electrophoresis, high-throughput image analysis, and candidate picking coupled with sequencing mass spectrometry, we have followed the changes in protein expression profile that occur during the differentiation of 3T3-L1 fibroblasts into adipocytes in response to dexamethasone, isobutyl methyl xanthine and insulin, or to the PPARgamma agonist, ciglitazone. Using this technique we have found alterations in the profile of over 2000 protein species during adipogenesis. Our studies reveal previously unknown alterations during adipogenesis in the expression or mobility (on sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of coactosin, which promotes actin filament destabilization, several signalling molecules, including RhoGDI-1, RhoGDI-2 and EHD1, and NEDD5 a protein involved in cytokinesis.

Precision of bone densitometry measurements: when is change true change and does it vary across bone density values?

The precision error of the bone densitometer is used to interpret significant change in bone mineral density (BMD) in serial studies. The precision error can be expressed as standard deviation (SD) or coefficient of variation (CV). The aims of this study are to determine the precision error over a range of BMD values and to demonstrate the application of the precision error in clinical practice. A bone phantom was used consisting of a perspex block with eight compartments containing varying amounts of hydroxyapatite powder to simulate a range of bone densities. The block was scanned 21 times and manual regions placed over each compartment to measure the BMD in each compartment. There were no significant differences in the variances or SD for all eight compartments, that is, over the range of BMD normally encountered in clinical practice. However, the calculated CV show a progressive fall in values as the BMD rises. Therefore, the SD should be used to calculate significant BMD change. In a practise with quality control procedures in place to detect calibration drift and with appropriately trained personnel, a change of approximately 0.05 g/cm2 is generally regarded as being a significant change at a 95% confidence level.

The diagnostic role of dual femur bone density measurement in low-impact fractures

A high correlation has been documented between the left and right femoral bone mineral densities in the normal population. This suggests that dual femur measurements are not justified in clinical practice. This study evaluated whether this premise holds for subjects who have lost bone mass and have sustained fractures with minimal trauma. Seventy-eight women aged 31-83 years (mean=66 years) with previous low-impact fractures had both proximal femora measured using dual-energy X-ray absorptiometry. There were significant correlations between values in the left and right total hip (TH) (r=0.95; p<0.05) and in the left and right femoral neck (FN) (r=0.90; p<0.05). The mean differences between the left and right TH and FN densities were not significant. However, the range of the limits of agreement for the TH (-0.074 to 0.086 g/cm2) and FN (-0.115 to 0.105 g/cm2) were greater than the 95% confidence interval for true change for the TH (0.05 g/cm2) and FN (0.07 g/cm2). Any longitudinal BMD assessment therefore needs to measure the same proximal femur to get a reliable comparison. A one-tailed analysis showed that for the TH, 7.5% of subjects had a T-score discordance greater than or equal to 0.5 and 0.5% had a T-score discordance greater than or equal to 1. For the FN, 9% had a T-score discordance greater than or equal to 0.5 and 2.5% had a T-score discordance greater than or equal to 1. The use of dual femur measurements increases the diagnostic yield by about 10% in subjects with prior minimal trauma fractures.

Centralized assessment of dual-energy X-ray absorptiometry (DEXA) in multicenter studies of HIV-associated lipodystrophy

BACKGROUND

The accurate measurement of total body and subcutaneous fat is essential if therapeutic interventions, aimed at preventing or reversing lipodystrophy syndrome, are to be adequately assessed. The aim of this study was to investigate the variability of dual-energy X-ray absorptiometry (DEXA) scans analysis performed at local sites compared to central analysis in a multicenter clinical trial.

METHOD

The PIILR study was a multicenter randomized clinical trial in which 80 HIV-infected patients with physician-documented lipodystrophy had serial measurements of body composition performed with Lunar DEXA scans. Scans were analyzed at local sites and then were reanalyzed centrally.

RESULTS

DEXA scans from 73 patients who completed 24 weeks study were compared. Greater variation in the locally analyzed results than in the centrally reanalyzed data was noted, with arm, leg, and combined limb fat being most divergent between the local and centralized assessments (ratio of local to central standard deviation was 1.28, 1.31, and 1.35, respectively). The magnitude of this variance was enough to alter statistically relevant differences between study populations.

CONCLUSION

Quality assurance is an important issue in the use of DEXA scans to determine body fat composition in multicenter research studies. A central quality assurance site should be incorporated to reduce variability in results.

Solitary pulmonary nodules: accuracy and cost-effectiveness of sodium iodide FDG-PET using Australian data

This study uses Australian data to confirm the accuracy of dedicated sodium iodide (NaI) fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in evaluating indeterminate solitary pulmonary nodules (SPNs) and to determine the conditions under which PET could play a cost-effective role in this evaluation. Ninety-two patients from two Australian hospitals in different states underwent FDG-PET for evaluation of an SPN. Observed values for prior probability of malignancy and diagnostic accuracy of PET were applied to previously published decision tree models using published Australian health care costs. The accuracy of FDG-PET was 93% with a sensitivity of 92% and a specificity of 95%. The prior probability of malignancy (0.54), PET sensitivity and PET specificity indicated cost savings per patient of up to EUR 455 (Adollars 774) based on a PET cost of EUR 706 (Adollars 1,200). PET would remain cost-effective for levels of prior probability up to 0.8-0.9 and a PET cost of EUR 736-1,161 (Adollars 1,252-Adollars 1,974). It is concluded that NaI PET is accurate, cost saving and cost-effective for the characterisation of indeterminate pulmonary nodules in Australia. Comparison with previous reports from the United States confirms that FDG-PET can remain cost-effective despite population differences in medical costs, disease prevalence and PET diagnostic performance.

Acute administration of haloperidol induces apoptosis of neurones in the striatum and substantia nigra in the rat

Chronic administration of typical neuroleptics is associated with tardive dyskinesia in some patients. This dyskinetic syndrome has been associated with loss of GABAergic markers in the basal ganglia but the cause of these GABAergic depletions remains uncertain. Haloperidol, a commonly prescribed typical neuroleptic, is known to be toxic in vitro, possibly as a consequence of its conversion to pyridinium-based metabolites and potentially by raising glutamate-mediated transmission. We report here that the in vivo, acute administration of a large dose of haloperidol resulted in a microglial response indicative of neuronal damage. This was accompanied by an increase in the number of apoptotic cells in the striatum (especially in the dorsomedial caudate putamen) and in the substantia nigra pars reticulata. These apoptotic cells were characterised by the stereotaxic injection of a retrograde neuroanatomical tracer into the projection targets of the striatum and substantia nigra pars reticulata prior to the systemic injection of haloperidol. This procedure confirmed that the dying cells were neurones and demonstrated that within the striatum the majority were striatopallidal neurones though relatively high levels of apoptotic striatoentopeduncular neurones were also seen.The possibility that chronic administration of haloperidol could induce cumulative neuronal loss in the substantia nigra pars reticulata and thereby induce the pathological changes which lead to tardive dyskinesia is discussed.

Comparative evaluation of the DPX and DPX-IQ lunar densitometer systems following software upgrade

Bone densitometry research departments perform system and software upgrades infrequently in order to maintain high precision. This study compares the results obtained on a Lunar densitometer with DPX, and DPX-IQ installed to achieve year 2000 compliance. The DPX-IQ provides an improved femur edge detection algorithm with an expanded reference database. Two hundred data files for each measurement site acquired on DPX were reanalyzed on DPX-IQ. There was no change to the bone mineral density (BMD), bone mineral content (BMC), T-scores or Z-scores for the L2-L4 spine, radius (ultradistal and 33%), and total body. There was a significant high correlation for the femoral neck BMD (r = 0.98; p < 0.05). The mean differences in BMD, BMC, T-scores, and Z-scores at the femoral neck and Ward's and trochanteric regions were not significant (p > 0.05). The limits of agreement within the 95% confidence interval for the femoral neck BMD using the Bland and Altman method was between -0.057 and 0.063 g/cm(2). This order of magnitude magnifies the long-term precision error and alters the usual confidence limits for interpretation of true change in densitometry practice. Therefore, it is important for reanalysis of DPX data files with the DPX-IQ to be performed so that longitudinal changes in BMD can be accurately assessed.

Analysis of the CD151-alpha3beta1 integrin and CD151-tetraspanin interactions by mutagenesis

Transmembrane proteins of the tetraspanin superfamily are associated with various integrins and modulate their function. We performed mutagenesis analysis to establish structural requirements for the interaction of CD151 with the alpha3beta1 integrin and with other tetraspanins. Using a panel of CD151/CD9 chimeras and CD151 deletion mutants we show that the minimal region, which confers stable (e.g. Triton X-100-resistant) association of the tetraspanin with alpha3beta1, maps within the large extracellular loop (LECL) of CD151 (the amino acid sequence between residues Leu(149) and Glu(213)). Furthermore, the substitution of 11 amino acids (residues 195-205) from this region for a corresponding sequence from CD9 LECL or point mutations of cysteines in the conserved CCG and PXXCC motifs abolish the interaction. The removal of the LECL CD151 does not affect the association of the protein with other tetraspanins (e.g. CD9, CD81, CD63, and wild-type CD151). On the other hand, the mutation of the CCG motif selectively prevents the homotypic CD151-CD151 interaction but does not influence the association of the mutagenized CD151 with other tetraspanins. These results demonstrate the differences in structural requirements for the heterotypic and homotypic tetraspanin-tetraspanin interactions. Various deletions involving the small extracellular loop and the first three transmembrane domains prevent surface expression of the CD151 mutants but do not affect the CD151-alpha3beta1 interaction. The CD151 deletion mutants are accumulated in the endoplasmic reticulum and redirected to the lysosomes. The assembly of the CD151-alpha3beta1 complex occurs early during the integrin biosynthesis and precedes the interaction of CD151 with other tetraspanins. Collectively, these data show that the incorporation of CD151 into the "tetraspanin web" can be controlled at various levels by different regions of the protein.

Standardized perfusion value: universal CT contrast enhancement scale that correlates with FDG PET in lung nodules

The standardized enhancement value and standardized perfusion value allow comparison between different methods for quantification of contrast enhancement during computed tomography (CT). Standard perfusion values calculated from CT measurements of perfusion within pulmonary nodules compared favorably with those derived from previously reported enhancement data and correlated with standardized uptake values obtained from positron emission tomographic images (r = 0.8, P <.01).

Dexamethasone induces limited apoptosis and extensive sublethal damage to specific subregions of the striatum and hippocampus: implications for mood disorders

It has been shown previously that the synthetic corticosteroid dexamethasone induces apoptosis of granule cells in the dentate gyrus and striatopallidal neurons in the dorsomedial caudate-putamen. We investigated whether or not dexamethasone can induce damage to other neuronal populations. This issue was addressed using OX42 immunohistochemistry to visualise activated microglia and thereby gauge the extent of dexamethasone-induced neuronal death. A single dose of dexamethasone (20mg/kg, i.p.) administered to young male Sprague-Dawley rats induced a strong microglial reaction which was restricted to the striatum, the dentate gyrus and all of the CA subfields of the hippocampus. Some OX42-immunoreactive cells were also seen in the lateral septal nucleus. Subsequent quantitative analysis of silver/methenamine-stained sections confirmed that acute administration of dexamethasone induced apoptosis in the striatum and all regions of the hippocampus at doses as low as 0.7mg/kg. In contrast, dexamethasone failed to induce apoptosis in the lateral septal nucleus at doses up to 20mg/kg. The levels of dexamethasone-induced striatal and hippocampal apoptosis were attenuated by pretreatment with the corticosteroid receptor antagonist RU38486 (Mifepristone), which implies that the cell death was mediated by a corticosteroid receptor-dependent process. We further determined whether dexamethasone induced sublethal damage to neurons by quantifying reductions in the number of microtubule-associated protein-2-immunoreactive striatal and hippocampal cells following injection of the corticosteroid. Dexamethasone induced dramatic decreases in the striatum, with the dorsomedial caudate-putamen being particularly affected. Similar damage was seen in the hippocampus, with the dentate gyrus and CA1 and CA3 subfields being particularly vulnerable.Equivalent corticosteroid-induced neuronal damage may occur in mood disorders, where the levels of endogenous corticosteroids are often raised. Corticosteroid-induced damage of striatal and hippocampal neurons may also account for some of the cognitive deficits seen following administration of the drugs to healthy volunteers.

Pharmacological mechanisms mediating phencyclidine-induced apoptosis of striatopallidal neurons: the roles of glutamate, dopamine, acetylcholine and corticosteroids

Phencyclidine (PCP) has recently been shown to induce apoptosis of a subpopulation of striatopallidal neurons which lie in the dorsomedial caudate-putamen. The pharmacological mechanisms underlying this PCP-induced striatal death were investigated in a series of small experiments. Striatal silver-methenamine-stained sections from rats injected acutely with dizocilpine (MK-801; 1.5-5 mg/kg, i.p.) were analysed to determine whether other non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists could induce apoptotic-like changes in striatal cells. The effects of amphetamine (3-12 mg/kg, i.p.) were similarly investigated as PCP can elevate extracellular dopamine levels and dopamine has the potential to be neurotoxic. The potential involvement of dopamine transmission in PCP-induced striatal apoptosis was also tested by determining the effect of co-administering SCH23390 (D1 dopamine receptor antagonist) and quinpirole (D2 dopamine receptor agonist) on PCP (80 mg/kg, s.c.)-induced striatal apoptotic-like cell death. Equivalent experiments were performed using scopolamine (cholinergic antagonist) as this drug blocks PCP-induced damage of the retrosplenial cortex and RU38486 (corticosteroid receptor antagonist) as a similar subpopulation of striatal neurons undergoes apoptosis following dexamethasone administration. Injection of neither MK-801 nor amphetamine induced elevations of apoptotic-like cells in the striatum nor did co-administration of SCH23390 or scopolamine affect the levels of PCP-induced striatal cell death. In contrast, quinpirole elevated the levels of PCP-induced apoptotic-like striatal cell death and RU38486 markedly reduced it. Within the retrosplenial cortex, scopolamine lowered PCP-induced apoptotic-like cell death whereas RU38486 was without effect. These results suggest that PCP-induced striatal apoptosis results from a corticosteroid-dependent mechanism. The results further demonstrate that different pathological mechanisms underlie PCP-induced neuronal damage in the striatum and the retrosplenial cortex.

The selective vulnerability of striatopallidal neurons

The different types of striatal neuron show a range of vulnerabilities to a variety of insults. This can be clearly seen in Huntington's disease where a well mapped pattern of pathological events occurs. Medium spiny projection (MSP) neurons are the first striatal cells to be affected as the disease progresses whilst interneurons, in particular the NADPH diaphorase positive ones, are spared even in the late stages of the disease. The MSP neurons themselves are also differentially affected. The death of MSP neurons in the patch compartment of the striatum precedes that in the matrix compartment and the MSP neurons of the dorsomedial caudate nucleus degenerate before those in the ventral lateral putamen. The enkephalin positive striatopallidal MSP neurons are also more vulnerable than the substance P/dynorphin MSP neurons. We review the potential causes of this selective vulnerability of striatopallidal neurons and discuss the roles of endogenous glutamate, nitric oxide and calcium binding proteins. It is concluded that MSP neurons in general are especially susceptible to disruptions of cellular respiration due to the enormous amount of energy they expend on maintaining unusually high transmembrane potentials. We go on to consider a subpopulation of enkephalinergic striatopallidal neurons in the rat which are particularly vulnerable. This subpopulation of neurons readily undergo apoptosis in response to experimental manipulations which affect dopamine and/or corticosteroid levels. We speculate that the cellular mechanisms underlying this cell death may also operate in degenerative disorders such as Huntington's disease thereby imposing an additional level of selectivity on the pattern of degeneration. The possible contribution of the selective death of striatopallidal neurons to a number of clinically important psychiatric conditions including obsessive compulsive disorders and Tourette's syndrome is also discussed.

Phencyclidine induces D-1 dopamine receptor mediated Fos-like immunoreactivity in discretely localised populations of striatopallidal and striatoentopeduncular neurons in the rat

Phencyclidine (PCP), a non-competitive antagonist of the NMDA subtype of glutamate receptor, which also acts as an indirect dopamine agonist and at sigma sites, can induce a long lasting psychotic state when taken acutely. It is well established that PCP is toxic to specific limbic structures and we have recently demonstrated that it induces apoptosis of a subpopulation of striatal neurons. These neurons lie predominantly in the dorsomedial striatum and project to the globus pallidus. The mechanisms mediating this neuronal death are unclear though manipulations of dopamine transmission can induce striatal c-fos expression and continuous c-fos expression has been implicated in the molecular cascades controlling apoptosis. We accordingly undertook a series of experiments to determine the action of PCP on striatal Fos-like immunoreactivity (FLI). PCP (80 mg/kg, s.c.) elicited FLI in three distinct striatal areas, namely dorsomedial, dorsolateral and the nucleus accumbens. The level of PCP-induced FLI was consistently attenuated by the co-administration of the D-1 antagonist, SCH 23390. Vehicle injections also induced modest levels of FLI in the dorsomedial striatum and the nucleus accumbens which again were attenuated by SCH 23390. The type of striatal neuron in which PCP-induced FLI was determined by the use of a retrograde anatomical tracer. A colloidal gold tracer was thus injected into the major areas of termination of striatal projection neurons prior to the administration of PCP. This procedure demonstrated that the majority of the FLI positive striatal cells were striatopallidal neurons, though some FLI positive striatoentopeduncular neurons were also seen. The potential pharmacological mechanisms underlying the results are discussed. It is argued that the complex pattern of PCP-induced striatal FLI might be accounted for by a differential action upon extracellular dopamine levels whereby they are elevated in some striatal areas and simultaneously reduced in others.

Insulin-stimulated expression of c-fos, fra1 and c-jun accompanies the activation of the activator protein-1 (AP-1) transcriptional complex

The activator protein-1 (AP-1) transcriptional complex is made up of members of the Fos (c-Fos, FosB, Fra1, Fra2) and Jun (c-Jun, JunB, JunD) families and is stimulated by insulin in several cell types. The mechanism by which insulin activates this complex is not well understood but it is dependent on the activation of the Erk1 and Erk2 isoforms of mitogen-activated protein kinases. In the current study we show that the AP-1 complex isolated from insulin-stimulated cells contained c-Fos, Fra1, c-Jun and JunB. The activation of the AP-1 complex by insulin was accompanied by (i) a transient increase in c-fos expression, and the transactivation of the ternary complex factors Elk1 and Sap1a, in an Erk1/Erk2-dependent fashion; (ii) a substantial increase in the expression of Fra1 protein and mRNA, which was preceded by a transient decrease in its electrophoretic mobility upon SDS/PAGE, indicative of phosphorylation; and (iii) a sustained increase in c-jun expression without increasing c-Jun phosphorylation on serines 63 and 73 or activation of the stress-activated kinase JNK/SAPK. In conclusion, insulin appears to stimulate the activity of the AP-1 complex primarily through a change in the abundance of the components of this complex, although there may be an additional role for Fra1 phosphorylation.

Phencyclidine and corticosteroids induce apoptosis of a subpopulation of striatal neurons: a neural substrate for psychosis?

Phencyclidine, a non-competitive N-methyl-D-aspartate receptor antagonist and indirect dopamine agonist, has neuroprotective properties. Phencyclidine, however, can also exert toxic effects and causes degeneration of neurons in the retrosplenial cortex. In this paper we demonstrate that acute administration of a high dose of phencyclidine to rats, (80 mg/kg), also causes death of a subpopulation of striatal neurons. The dying cells exhibited many of the morphological and biochemical features of cells undergoing apoptosis as revealed by a silver methenamine stain, propidium iodide fluorescence histochemistry and a TUNEL procedure. The majority of the dying cells tended to be clustered within the dorsomedial aspect of the striatum. The type of striatal cell undergoing apoptosis was determined by stereotaxically injecting a colloidal gold retrograde anatomical tracer into the major areas of striatal termination prior to the administration of phencyclidine. This procedure demonstrated that phencyclidine induced striatal apoptosis is almost exclusively limited to striatopallidal neurons. A similar series of experiments was conducted to determine whether the synthetic corticosteroid, dexamethasone, also induces apoptosis of striatal neurons. Corticosteroids are known to be toxic to hippocampal neurons and interact with striatal dopamine transmission. Acute administration of dexamethasone, (20 mg/kg), induced apoptosis of a subpopulation of striatal cells. As was the case with phencyclidine, most of the dexamethasone-induced apoptotic striatal cells were striatopallidal neurons located within the dorsomedial striatum. The pathology during the early stages of Huntington's disease is restricted to an equivalent subpopulation of striatal neurons. Many Huntington's patients are extremely psychotic during this stage in the progression of the disease. Psychosis is also associated with the acute administration of both phencyclidine and dexamethasone to humans. We accordingly speculate that the selective loss of striatopallidal neurons in the dorsomedial striatum may represent the neural substrate of many forms of psychosis.

Cerebral perfusion scanning in treating AIDS dementia: a pilot study

Acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) is a common effect of the AIDS virus. We studied the regional cerebral blood flow of patients with early ADC and its response to atevirdine mesylate.

METHODS

Ten men with early ADC, who had failed or were intolerant to zidovudine or didanosine therapy, were treated with atevirdine mesylate for 12 wk. Cerebral perfusion SPECT using 99mTc-HMPAO was performed at Week 0 and Week 12. SPECT images were analyzed qualitatively and semiquantitatively.

RESULTS

The cerebral perfusion abnormalities in early ADC were usually mild and characteristically involved the cortices and periventricular regions bilaterally and symmetrically. Four patients were able to complete the protocol. Three of these patients responded to atevirdine clinically, two of whom showed improvement in their Week 12 SPECT images. The other responder had an essentially unchanged image. The patient who did not respond to atevirdine showed a definite deterioration in cerebral perfusion.

CONCLUSION

Cerebral perfusion SPECT is useful in detecting and assessing therapeutic responses in ADC. The preliminary results of atevirdine in treating ADC are promising and need further investigation.

Two naturally occurring insulin receptor tyrosine kinase domain mutants provide evidence that phosphoinositide 3-kinase activation alone is not sufficient for the mediation of insulin's metabolic and mitogenic effects

We have recently reported (1) that two naturally occurring mutants of the insulin receptor tyrosine kinase domain, Arg-1174 --> Gln and Pro-1178 --> Leu (Gln-1174 and Leu1178, respectively), both found in patients with inherited severe insulin resistance, markedly impaired receptor tyrosine autophosphorylation, with both mutant receptors being unable to mediate the stimulation of glycogen synthesis or mitogenesis by insulin when expressed in Chinese hamster ovary cells. However, these mutations did not fully prevent IRS-1 phosphorylation in response to insulin in these cells, suggesting that IRS-1 alone may not be sufficient to mediate insulin's metabolic and mitogenic effects. In the present study, we have demonstrated that these mutations also impair the ability of the insulin receptor to activate the transcription factor Elk-1 and promote GLUT4 translocation to the plasma membrane. Although at low concentrations of insulin, the mutant receptors were impaired in their ability to stimulate the tyrosine phosphorylation of IRS-1, at higher insulin concentrations we confirmed that the cells expressing the mutant receptors showed significantly increased tyrosine phosphorylation of IRS-1 compared with parental nontransfected cells. In addition, at comparable insulin concentrations, the association of the p85alpha subunit of phosphoinositide 3-kinase (PI3-kinase) with IRS-1 and the enzymatic activity of IRS-1-associated PI3-kinase were significantly enhanced in cells expressing the mutant receptors. In contrast, no significant stimulation of the tyrosine phosphorylation of Shc, GTP loading of Ras, or mitogen-activated protein kinase phosphorylation was seen in cell lines expressing these mutant receptors. Thus, no activation of any measurable mitogenic or metabolic response was detectable, despite significant insulin-induced phosphorylation of IRS-1 and its association with PI3-kinase in cells stably expressing the mutant insulin receptors. These findings suggest that PI3-kinase activation alone may be insufficient to mediate a wide range of the metabolic and mitogenic effects of insulin. Additionally, the data provide support for the notion that insulin activation of Ras is more closely linked with Shc, and not IRS-1, phosphorylation.

Plasma protein C inhibitor is elevated in survivors of myocardial infarction

Many studies have shown alterations of the hemostatic and fibrinolytic systems in patients with atherosclerotic disease, principally in levels of plasminogen activator inhibitor-1. However, in a large prospective study only fibrinogen, von Willebrand factor antigen, and tissue plasminogen activator antigen were found to be independent risk markers for acute coronary events. The present study evaluated the fibrinolytic system in coronary artery disease, paying particular attention to another inhibitor of fibrinolysis, plasminogen activator inhibitor-3, also called protein C inhibitor (PCI). One hundred fifteen nonanticoagulated male survivors of myocardial infarction were investigated for a range of hemostatic and fibrinolytic parameters that were compared with values in 87 age-matched healthy control male subjects. PCI active antigen was significantly (P < .03) elevated in the myocardial infarction group compared with the control group and was associated with the number of acute coronary events suffered (P = .005) but not with the severity of disease as determined by coronary angiography. Elevated PCI plasma levels can be considered as a risk marker for acute coronary events and might be of particular importance in the pathogenesis of this disease due to the interference of PCI in both the anticoagulant and fibrinolytic systems.

Magnification error of femoral geometry using fan beam densitometers

Hip axis length (HAL) has been reported as an independent risk factor for hip fracture. DEXA machines using fan beam techniques have become increasingly available. Errors in calculated hip axis length may be expected because of different degrees of magnification by the fan beam. The magnitude of this error on measurement of hip geometry was studied, using an anthropomorphic femur phantom with both fan beam (Lunar Expert and Hologic QDR-2000) and pencil beam (Lunar DPXL) densitometers. The clinical relevance of these findings was also examined using patient measurements of buttock soft tissue thickness. Femoral neck axis length (FNAL), which correlates well with HAL, was used as a measurement of hip geometry. There was a linear increase or decrease of FNAL with increasing distance of the phantom above the scanning table, when measured with the Lunar Expert or Hologic QDR-2000, respectively. There was no significant difference in FNAL at different heights using the pencil beam densitometer. The maximal difference in buttock soft tissue thickness in 30 women studied was 8.7 cm. From the equations, derived from the phantom studies, this difference would result in an 8.2% (1.4 SD) increase, or an 11.4% (1.9 SD) decrease in FNAL in the largest woman as compared with the smallest woman when measured using the Lunar Expert or Hologic QDR-2000, respectively. We conclude that there may be unpredictable degrees of magnification of FNAL in vivo, caused by differences in buttock thickness, when measured using a fan beam densitometers. Until these problems are resolved. FNAL, or related parameters of femoral geometry, should be measured using pencil beam instruments.

Correcting the magnification error of fan beam densitometers

Dual-energy X-ray absorptiometry (DXA), using a narrow pencil-shaped X-ray beam coupled to a single detector, has been used extensively. More recently, DXA using a fan- shaped X-ray beam coupled to an array of detectors has been introduced. This new generation of scanners causes an inherent magnification of scanned structures as the distance from the X-ray source decreases. This magnification, which occurs in the medial-lateral direction but not in the craniocaudal direction, does not affect bone mineral density (BMD). There are, however, significant changes of bone mineral content (BMC), bone area, and parameters of hip geometry, with varying distance of the bone scanned from the X-ray source. Variability of soft tissue thickness in vivo, by altering the distance of the skeleton from the scanning table and X-ray source, may cause clinically significant errors of BMC, bone area, and proximal femur geometry when measured using fan-beam densitometers. We analyzed the geometry of Lunar and Hologic fan beam scanners to derive equations expressing the true width of scanned structures in terms of the apparent width and machine dimensions. We also showed mathematic ally that performing an additional scan, at a different distance from the X-ray source than the first scan, provides simultaneous equations that can be solved to derive the real width of a scanned bone. This hypothesis was tested on the Lunar Expert using aluminium phantoms scanned at different table heights. There was an excellent correlation, r = 0.99 (p < 0.001), between the predicted phantom width and the measured phantom width. In conclusion, this study shows that the magnification error of fan beam DXA can be corrected using a dual scanning technique. This has important implications in the clinical usefulness of BMC and geometrical measurements obtained from these scanners.

Light microscopic and ultrastructural distribution of type VI collagen in human liver: alterations in chronic biliary disease

We have investigated the distribution of type VI collagen in normal human liver obtained from cadaveric renal transplant donors, using a peroxidase-antiperoxidase method for light microscopic visualization, and an immunogold labelling method for ultrastructural localization. The distribution was compared with that of the more abundant interstitial collagen type III, using antibodies to amino terminal procollagen type III. Staining for type VI collagen was identified in Glisson's capsule, in portal tract stroma and within the space of Disse. Perisinusoidal staining showed intra-acinar heterogeneity with the intensity in acinar zones 2 and 3 being greater than in zone 1. Type III collagen was also found in the space of Disse although no significant intra-acinar variation in staining intensity was noted. Immuno-gold labelling for type VI collagen was demonstrated on amorphous or microfilamentous material lying between, and occasionally appearing to interconnect, cross-striated collagen fibrils, whereas labelling for amino terminal procollagen type III was exclusively on fibrils. Intracellular staining for type VI collagen was noted in perisinusoidal (lto) cells. These results confirm that type VI collagen is a ubiquitous constituent of the normal hepatic extracellular matrix and suggest that it may be synthesized by perisinusoidal (lto) cells. The distribution of type VI collagen was also studied in biopsy material from patients with different histological stages of primary biliary cirrhosis. Intense staining was noted around proliferating bile ductules within developing fibrous septa and in established septa of cirrhotic liver. These observations indicate that this 'minor' matrix component may play an important role in hepatic fibrogenesis.

A comparison of morphoea and lichen sclerosus et atrophicus in vitro: the effects of para-aminobenzoate on skin fibroblasts

To study the effects of para-aminobenzoate on the dermis, fibroblast cell lines derived from lesions of lichen sclerosus et atrophicus, from morphoea and from normal skin were incubated with Potaba in vitro. Monolayer cultures containing Potaba showed a dose-dependent inhibition of proliferation beginning at 1,000 micrograms/ml with total inhibition at 10,000 micrograms/ml. Mean ID50 values for the three groups were not significantly different. There was a similar dose dependent inhibition of glycosaminoglycan secretion in all 3 groups, except at 10,000 micrograms/ml where secretion by lichen sclerosus et atrophicus and morphoea fibroblasts was significantly more inhibited than normal lines. Inhibition of the glycosaminoglycan secretion at 10-1,000 micrograms/ml was a direct effect of the drug rather than an indirect effect of changes in cell density, and lichen sclerosus et atrophicus fibroblasts produced about 40% more GAG than the morphoea or normal lines growing at similar densities. Collagen synthesis was increased in both lichen sclerosus et atrophicus and morphoea cell lines, with increased non-collagenous protein in morphoea lines. These results confirm that there are differences between lichen sclerosus et atrophicus and morphoea, and suggest glycosaminoglycan secretion as a possible target for the therapeutic action of Potaba.

Basement membrane proteins in the space of Disse: a reappraisal

The distribution of two major basement membrane components, type IV collagen and laminin, was studied within the perisinusoidal space of Disse in normal human liver using (i) an immunoperoxidase method for light microscopy and (ii) immunogold labelling for ultrastructural localisation. Although immunoreactivity depended on the mode of tissue fixation, both proteins could be identified at this site using a panel of affinity purified antibodies. These findings indicate that these proteins are normal constituents of the perisinusoidal extracellular matrix, and refute the hypothesis that capillarization of the sinusoids in chronic liver disease results from neo-expression of laminin in the space of Disse.

Immunohistochemical localization of a plasma protein (glycoprotein 60) which inhibits complement-mediated prevention of immune precipitation

Using various immunocytochemical techniques it has been shown that glycoprotein 60 (gp60), an IgG Fc-binding protein recently isolated from normal human plasma, is found localized in human hepatocytes, platelets and a subpopulation of normal peripheral blood lymphocytes (PBL). This protein, which appears to be identical to a 60,000 MW IgG-binding protein (60-IBF) previously isolated from normal human PBL culture supernatants, also appears to be distinct from the three well-defined leucocyte Fc gamma-receptors: Fc gamma RI, Fc gamma RII and Fc gamma RIII.

Ultrastructural localization of extracellular matrix proteins in liver biopsies using ultracryomicrotomy and immuno-gold labelling

We describe a technique for the localization of extracellular matrix proteins in wedge and needle biopsy specimens of human liver. Using ultra-thin (50-70 nm) sections of puncture perfusion fixed tissue, extracellular matrix proteins were localized using a protein A-gold labelling procedure. We obtained good preservation of ultrastructural detail and specific labelling for collagen types I, III and IV and fibronectin. The method represents a sensitive means of identifying the extracellular distribution and the cellular origin of these proteins in normal and diseased human liver.

Intrasplenic hepatocyte transplantation in rats with experimental liver injury: morphological and morphometric studies

Isolated rat hepatocytes were transplanted into the splenic parenchyma of syngeneic animals. The effects on the degree of colonization by the transplanted cells of three forms of experimental liver injury in recipient animals were studied. Significant colonization was observed in animals with carbon tetrachloride (CCl4)-induced injury combined with portacaval shunt (PCS) and in animals with common bile duct (CBD) ligation but not in control animals or in animals with CCl4-induced injury alone. Transplanted cells in the CCl4/PCS group resembled normal hepatocytes. In contrast, in the CBD group, the intrasplenic hepatocytes exhibited a pattern of 'ductular metaplasia' similar to that observed in the obstructed liver of the recipients. Transplanted syngeneic hepatocytes can thus proliferate in the spleen in response to liver injury in the recipient. The morphological appearances of the transplanted cells can be modified depending on the nature of the liver injury.

Localization of adrenergic and neuropeptide tyrosine-containing nerves in the mammalian liver

The distribution of adrenergic nerves in guinea pig and rat liver was studied by the immunolocalization of fibers containing tyrosine hydroxylase and dopamine beta-hydroxylase, enzymes involved in the synthesis of catecholamines. In both species, adrenergic fibers were identified within portal tracts, often in close proximity to hepatic artery branches. In guinea pig liver, but not rat liver, abundant intraacinar fibers were identified; fibers were also seen within the walls of terminal hepatic vein radicles and larger hepatic veins. The presence of peptidergic nerves containing the regulatory peptide neuropeptide tyrosine and the C-flanking peptide CPON was investigated by indirect immunofluorescence. The distribution of these nerves was similar to that of tyrosine hydroxylase- and dopamine beta-hydroxylase-positive nerves and showed the same species difference. The effector sympathetic nature of tyrosine hydroxylase- and neuropeptide tyrosine-positive fibers in rat liver was confirmed by chemical denervation studies using 6-hydroxydopamine.