Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits

We determined the pulmonary diffusing capacity (DL) for 18O-labeled CO2 (C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing 0.9% C18O2 or 0.05% NO in nitrogen, with breath-holding periods ranging from 0 to 1 s for C18O2 and from 2 to 8 s for NO. The alveolar partial pressures of C18O2 and NO were determined by using respiratory mass spectrometry. DL was calculated from gas exchange during inflation, breath hold, and deflation. We obtained values of 14.0 +/- 1.1 and 2.2 +/- 0.1 (mean value +/- SD) ml.mmHg-1.min-1 for DL(C18O2) and Dl(NO), respectively. The measured DL(C18O2)/DL(NO) ratio was one-half that of the theoretically predicted value according to Graham's law (6.3 +/- 0.5 vs. 12, respectively). Analyses of the several mechanisms influencing the determination of DL(C18)2 and DL(NO) and their ratio are discussed. An underestimation of the membrane diffusing component for CO2 is considered the likely reason for the low DL(C18O2)/DL(NO) ratio obtained.

Single-breath diffusing capacities for NO, CO and C18O2 in rabbits

Nitric oxide (NO) has been introduced recently for studying alveolar-capillary gas transfer. Due to extremely fast reaction kinetics for the association of NO with haemoglobin, pulmonary NO uptake is expected to depend only on diffusion, whereas in the case of carbon monoxide (CO) or oxygen-labelled carbon dioxide (C18O2) the alveolar-capillary transfer is, in addition, known to depend on a blood uptake component. To provide further data for NO, CO and C18O2, we determined the pulmonary diffusing capacities (DL) for the indicator gases mentioned, performing single-breath manoeuvres on ten rabbits. The inspired gas mixtures contained 0.05% NO and/or 0. 2% CO or 1% C18O2 in nitrogen. Applying respiratory mass spectrometry to the expirates we obtained the following mean +/- SD values: DL,NO/DL,CO = 3.55 +/- 0.4, DL,C18O2/DL,NO = 6.0 +/- 0.6, DL, C18O2/DL,CO = 21.4 +/- 2.5. Graham's law predicts DL ratios of 1.9 for NO/CO, 12 for C18O2/NO, and 23 for C18O2/CO. Thus we equally underestimated the predicted DL ratios for C18O2/NO and CO/NO by a factor of approximately 0.5. From this, and by excluding significant interactions between the indicator gases and lung tissues, we conclude that the closest approximation of the diffusive component of DL is indeed obtained by using NO.

Stratification does not limit O2 uptake in rabbit lungs

This study was performed to assess the role of stratification, i.e. axial gas mixing deficit within alveolar space, in limiting alveolar gas exchange for oxygen. The single-breath method for varying breath-holding time with oxygen-labelled carbon dioxide, C18O2, was applied to 10 anaesthetized, paralysed and artificially ventilated rabbits. Alveolar partial pressure of C18O2 was analysed using respiratory mass spectrometry. Starting from residual volume, the lungs were rapidly inflated using 40 mL of indicator gas mixture (1% C18O2 in nitrogen). After executing breath-holding, the lungs were rapidly deflated. Pulmonary diffusing capacity of carbon monoxide was determined in the same way. On the basis of a serial compartment model, the lower limit of the stratificational conductance of oxygen was estimated, using the rate constant of C18O2 removal from alveolar space (4 s-1) and Graham's law. We found that the stratificational conductance in rabbits amounts to at least 13.5 mL mmHg-1 min-1. The pulmonary diffusing capacity of oxygen was calculated by multiplying the carbon monoxide diffusing capacity of rabbit lungs by a factor of 1.2, yielding a value of 0.77 mL mmHg-1 min-1. These results show that stratificational conductance is at least 17.5 times higher than pulmonary oxygen diffusing capacity, indicating that stratification does not limit oxygen uptake in rabbit lungs.

Single-breath diffusing capacity of NO independent of inspiratory NO concentration in rabbits

Pulmonary diffusing capacity of NO (DLNO) was determined by performing single-breath experiments on six anesthetized paralyzed supine rabbits, applying inspiratory concentrations of NO (FINO) within a range of 10 parts per million (ppm) < or = FINO < or = 800 ppm. Starting from residual volume, the rabbit lungs were inflated by 50 ml of a NO-nitrogen-containing indicator gas mixture. Breath-holding time was set at 0.1, 1, 3, 5, and 7 s. Alveolar partial pressure of NO was determined by analyzing the end-tidal portion from expirates, with the use of respiratory mass spectrometry. In the six animals, pulmonary diffusing capacity of NO averaged DLNO = 1.92 +/- 0.21 ml.mmHg-1.min-1 (mean +/- SD value). Despite extreme variations in FINO, we found very similar DLNO values, and in three rabbits we found identical values even at such different FINO levels of 80 ppm or 500, 20, or 200 ppm as well as 10 or 800 ppm. There was also no dependence of DLNO on the respective duration of the single-breath maneuvers. In addition, the time course of NO removal from alveolar space was independent of applied FINO levels. These results suggest that DLNO determinations are neither affected by chemical reactions of NO in alveolar gas phase as well as in lung tissue nor biased by endogenous release of NO from pulmonary tissue. It is our conclusion that the single-breath diffusing capacity of NO is able to provide a measure of alveolar-capillary gas conductance that is not influenced by the biochemical reactions of NO.

Effect of inhaled nitric oxide on endotoxin-induced hypoxaemia in rabbits

In five mechanically ventilated rabbits, we studied the property of inhaled nitric oxide in helping to treat hypoxaemia which was induced by intravenous endotoxin (Escherichia coli-derived lipopolysaccharide, serotype 0111: B4). We used measurements of arterial partial pressure of oxygen to check a therapeutic nitric oxide benefit. Pulmonary artery pressure was continuously monitored. Furthermore, we determined the single-breath diffusing capacity for nitric oxide. Measurements of plasma nitrite/nitrate concentration served as an indicator of endogenous nitric oxide output. The first infusion of endotoxin led to a transient pulmonary vasoconstriction, whereas arterial partial pressure of oxygen was permanently reduced by 30 +/- 10 mmHg (mean +/- SD), attaining minimal values of 48 +/- 3.4 mmHg due to additional endotoxin. Single-breath diffusing capacity for nitric oxide declined by 20 +/- 5.5% of baseline values until the experiments were concluded. Endotoxin induced an increase in plasma nitrite/nitrate concentration in the five rabbits as well as in the control animals (four rabbits) without exogenous nitric oxide supply. During the 25 inhalations of nitric oxide (3-50 ppm), arterial oxygenation did not change significantly. Thus endotoxin permanently impaired pulmonary gas exchange without inducing pulmonary hypertension. Inhaled nitric oxide did not improve arterial oxygenation during endotoxaemia.

Integration of foreign DNA and its consequences in mammalian systems

The insertion of foreign DNA into the genomes of established cells and organisms and the consequences of this integration event are of significance for viral oncology, reverse genetics, transgenic organisms, human somatic gene therapy and evolution. This review summarizes recent experimental findings and focuses on the alteration of cellular DNA methylation at regions remote from the site of insertion. We also discuss experimental data demonstrating that foreign DNA ingested by mice is not completely degraded in their gastrointestinal tracts; fragments of this DNA have been found to be covalently linked to DNA with 70% homology to the mouse IgE receptor gene.

Spiral CT in the evaluation of flank pain: overall accuracy and feature analysis

PURPOSE

Our goal was to assess test reliability and identify those features that have the strongest positive and negative predictive values in the diagnosis of renal colic using spiral CT.

METHOD

Fifty non-contrast-enhanced CT scans (5 mm slice thickness) obtained in patients presenting with flank pain were reviewed by three radiologists blinded to the final diagnoses. The sensitivity, specificity, and positive and negative predictive values for nine pertinent findings were determined as compared to clinical follow-up.

RESULTS

Twenty-nine cases had findings of ureteral obstruction. Findings with the strongest positive predictive values (> 0.90) were ureteral stone, hydronephrosis, hydroureter, periureteral stranding, and ureterovesical junction edema. Findings with the strongest negative predictive values (> 0.89) were absence of hydronephrosis and hydroureter. The areas under the receiver operating curves for Readers 1, 2, and 3 were 0.970 +/- 0.030, 0.942 +/- 0.036, and 0.982 +/- 0.020.

CONCLUSION

Absence of hydroureter and hydronephrosis on spiral CT images should prompt a search for a diagnosis other than an obstructing ureteral stone.

Convection as one of the limiting factors of human respiration during normoxic exercise

Each of the pathways within respiration has been suspected of limiting maximal performance, suggesting that O2 transport may be affected by each single pathway. The use of the stable, isotopic O2 molecules 16O2 and 16O18O is presented as a novel method for assessing respiration. Because of their different molecular weights, 16O2 diffuses 3% more rapidly than 16O18O, whereas 16O2 is convectively transported as rapidly as 16O18O. This can be quantified by using the overall fractionation factor alpha O. The more diffusion becomes limiting, the more 16O2 is transported in preference to 16O18O and alpha O is increased to 1.03. By contrast, the more respiration is limited by convection, the closer alpha O comes to 1.0 during the entire O2 transport. Six untrained subjects underwent normoxic exercise on a cycle ergometer. Isotopic analysis was performed at rest and during exercise loads of 50, 100, 150, 200, and 250 W using respiratory mass spectrometry. With increasing workload, a decrease in alpha O from 1.0072 at rest to 1.0033 at 250 W was determined in all subjects. On the basis of a serial resistance model of respiration, we concluded that, in our subjects, O2 transport was increasingly affected by convection but decreasingly limited by diffusion. The relative contribution of convection to the entire resistance to O2 flow ranged from > or = 44.6% at rest to > or = 74.6% at the most strenuous level of exercise, whereas the diffusive pathways decreasingly contributed to resistance to O2 flow by < or = 24% at rest and < or = 11% at 250 W.

Spiral computerized tomography in the evaluation of acute flank pain: a replacement for excretory urography

PURPOSE

We determined the value of noncontrast enhanced spiral computerized tomography (CT) in the evaluation of suspected renal colic.

MATERIALS AND METHODS

Thin section (5 mm.) noncontrast enhanced CT was used to evaluate 100 patients presenting to the emergency room with flank pain. The 55 patients with ureteral obstruction were followed at the urology outpatient clinic and by telephone interview, while 45 without ureteral obstruction were followed by telephone interview and chart review. Sensitivity, specificity, and positive and negative predictive values for CT were determined, with passage, retrieval or identification of a stone on a retrograde study considered the gold standard for diagnosis.

RESULTS

A total of 89 patients had adequate clinical followup to assess outcome accurately. Of 55 patients with ureteral obstruction on CT 11 underwent endoscopic stone removal, while 44 were treated conservatively with stone passage documented in 39. Of the 45 patients without ureteral stones identified 38 did not pass calculi and CT provided a definite diagnosis in 14. There was 1 false-negative study. The results yielded 98% sensitivity, 100% specificity, and 100% positive and 97% negative predictive values.

CONCLUSIONS

Noncontrast enhanced spiral CT was accurate and reliable in detecting obstructing ureteral calculi in patients with flank pain.

Functional inhomogeneities in interstitial lung disease, assessed using (16)o(18)o

Abstract We investigated the contribution of diffusion limitation and functional inhomogeneities to the impairment of pulmonary oxygen (O(2)) transfer in interstitial lung disease (ILD). Analyses of (16)O(18)O/(16)O(2) ratios were performed on expiratory gas mixtures obtained from 6 ILD patients and 6 healthy humans at rest, applying respiratory mass spectrometry. We assessed O(2) transport by using the overall fractionation factor of respiration (α(0)) which is predicted to increase in the case of diffusion limitation. α(0) was reduced in patients (1.0065±3.10(-4)) when compared to the value for healthy subjects (1.0071±7.10(-4), P <0.05), pointing away from a diffusion limitation of O(2) transport. On the basis of a two-compartment model we interpreted our findings by assuming an unequal distribution of diffusion and convective O(2) transport in the pulmonary gas exchange of the patients.

Loss of lean body and muscle mass correlates with androgen levels in hypogonadal men with acquired immunodeficiency syndrome and wasting

The acquired immunodeficiency syndrome (AIDS) wasting syndrome (AWS) is a devastating complication of human immunodeficiency virus infection characterized by a disproportionate decrease in lean body mass. The pathogenesis of the AWS is unknown, but recent data suggest that endogenous secretion of the potent anabolic hormone, testosterone; is decreased in 30-50% of men with AIDS. However, it is unknown whether decreased androgen levels are associated with decreased lean body mass and/or functional decreases in muscle strength and aerobic capacity in hypogonadal men with the AWS. In addition, testosterone is known to have stimulatory effects on GH secretion, and the loss of these effects on the GH-insulin-like growth factor I (IGF-I) axis may be an additional mechanism of decreased lean body mass in this population. Twenty hypogonadal subjects (free-testosterone < 12 pg/mL) with weight loss > 10% of preillness weight or absolute weight < 90% ideal body weight (IBW) were enrolled in the study. None of the subjects were receiving Megace. Lean body mass and fat-free mass were determined by potassium-40 isotope analysis (40K) and dual-energy x-ray absorptiometry, respectively, and analyzed with respect to gonadal function by linear regression analysis. Muscle mass was determined by urinary creatinine excretion, and exercise functional capacity was assessed by a 6-min walk test, a sit-to-stand test, and a timed get-up-and-go test. Results also were compared with gonadal function by regression analysis. IGF-I and mean overnight GH levels, determined from frequent sampling (q20 min from 2000-0800 h), were compared with results obtained from age- and sex-matched normal controls. Subjects were 26-58 yr of age (39 +/- 7 yr, mean +/- SD) with a CD4 cell count of 150 +/- 186 cells/mm3. Serum levels of FSH were elevated in 30% of the subjects. Muscle mass was significantly reduced, compared with expected mass for height (23.3 +/- 5.5 vs. 29.3 +/- 1.7 kg, P = 0.0001) and was decreased disproportionately to weight (77% of expected value for muscle mass vs. 93% of expected value for weight). Free-testosterone levels were correlated with total body potassium (R = 0.45, P < 0.05) and muscle mass (R = 0.45, P < 0.05). Total-testosterone levels were correlated with exercise functional capacity (R = 0.64, P = 0.01 for the sit-to-stand test and R = 0.53, P < 0.05 for the 6-min walk test). Mean GH levels were significantly increased (3.03 +/- 1.76 vs. 0.90 +/- 0.37 ng/mL, P < 0.001) and IGF-I levels decreased (167 +/- 66 vs. 225 +/- 69 ng/mL, P < 0.01), compared with age- and sex-matched eugonadal controls. GH levels were inversely correlated with caloric intake (R = -0.60, P = 0.02) and percent fat mass by dual-energy x-ray absorptiometry (R = 0.58, P = 0.02). Six additional hypogonadal subjects receiving Megace for AIDS wasting were analyzed separately. Nutritional status and parameters of body composition were compared in the Megace and non-Megace-treated subjects. No significant differences in caloric intake, lean body mass, fat mass, or muscle mass were demonstrated. These data demonstrate that changes in body composition, including loss of lean body and muscle mass, and deterioration in exercise functional capacity are highly correlated with androgen levels in hypogonadal men with the AWS. Furthermore, our data demonstrate significantly increased GH levels and decreased IGF-I in association with low weight in this population. These data suggest that androgen deficiency combined with classical GH resistance may contribute to the critical loss of lean body and muscle mass in hypogonadal men with the AWS. These data are the first to link muscle and lean body wasting with progressive gonadal dysfunction among the large percentage of men with AIDS wasting who are hypogonadal. This demonstrates the need for additional studies to determine the efficacy of gonadal steroid replacement to increase lean body mass in this population.

Chromosomal distribution of the hamster intracisternal A-particle (IAP) retrotransposons

The retrotransposon-like elements of the intracisternal A-particle (IAP) sequences occur in about 900 copies per haploid hamster cell genome. By applying the fluorescent in situ hybridization (FISH) technique and four different, cloned segments of the IAP element as hybridization probes, these elements were found to be distributed in specific patterns over many of the 44 hamster chromosomes. The hybridization patterns were very similar regardless of whether all four probes or only the IAPI probe carrying the long terminal repeat (LTR) region were used. The IAP elements were found most abundantly, though not exclusively, on the short arms of at least 12 of the autosomes. Of the sex chromosomes, the shorter Y chromosome was stained on both arms, and the X chromosome on one arm by the IAP probes. Primary Syrian hamster cells, the established Syrian hamster cell line BHK21, and the adenovirus type 12 (Ad12)-transformed BHK21 cell line T637 yielded very similar results. In Chinese hamster ovary (CHO) or 3T3 mouse cells, signals could not be elicited by FISH using the Syrian hamster IAP probes. On Southern blots, the DNAs from these cell lines hybridized very weakly, if at all, to the IAP sequences. Thus, IAP sequences were retroposed after Syrian hamster and mouse or Syrian and Chinese hamsters had diverged in evolution.

Chromosomal insertion of foreign (adenovirus type 12, plasmid, or bacteriophage lambda) DNA is associated with enhanced methylation of cellular DNA segments

Insertion of foreign DNA into an established mammalian genome can extensively alter the patterns of cellular DNA methylation. Adenovirus type 12 (Ad12)-transformed hamster cells, Ad12-induced hamster tumor cells, or hamster cells carrying integrated DNA of bacteriophage lambda were used as model systems. DNA methylation levels were examined by cleaving cellular DNA with Hpa II, Msp I, or Hha I, followed by Southern blot hybridization with 32P-labeled, randomly selected cellular DNA probes. For several, but not all, cellular DNA segments investigated, extensive increases in DNA methylation were found in comparison with the methylation patterns in BHK21 or primary Syrian hamster cells. In eight different Ad12-induced hamster tumors, moderate increases in DNA methylation were seen. Increased methylation of cellular genes was also documented in two hamster cell lines with integrated Ad12 DNA without the Ad12-transformed phenotype, in one cloned BHK21 cell line with integrated plasmid DNA, and in at least three cloned BHK21 cell lines with integrated lambda DNA. By fluorescent in situ hybridization, the cellular hybridization probes were located to different hamster chromosomes. The endogenous intracisternal A particle genomes showed a striking distribution on many hamster chromosomes, frequently on their short arms. When BHK21 hamster cells were abortively infected with Ad12, increases in cellular DNA methylation were not seen. Thus, Ad12 early gene products were not directly involved in increasing cellular DNA methylation. We attribute the alterations in cellular DNA methylation, at least in part, to the insertion of foreign DNA. Can alterations in the methylation profiles of hamster cellular DNA contribute to the generation of the oncogenic phenotype?

On the insertion of foreign DNA into mammalian genomes: mechanism and consequences

We have studied the integration of adenovirus type 12 (Ad12) DNA in transformed and hamster tumor cells over many years. Upon infection of hamster cells with Ad12, viral DNA has been found in association with hamster chromosomes, possibly in part integrated into the host genome. Ad12 DNA integration is not sequence specific. Transcriptionally active sites of the host genome show a preponderance for foreign DNA insertion. We are pursuing the mechanism of Ad12 DNA integrative recombination in a cell-free system prepared from hamster cell nuclear extracts. In a number of Ad12-transformed hamster cell lines or in cell lines carrying foreign DNA, we have located the inserted Ad12 DNA copies on hamster chromosomes by fluorescent in situ hybridization (FISH). Among the consequences of Ad12 DNA integration, we have studied the de novo methylation of the integrated foreign (Ad12) DNA and increases in DNA methylation in several cellular genes and DNA segments in Ad12-transformed and hamster tumor cells. Several lines of evidence argue for the notion that parameters in addition to nucleotide sequence, in particular site of integration and/or the chromatin configuration of the integrated DNA, are important in generating de novo methylation patterns. The de novo methylation of integrated foreign DNA can be interpreted as an old cellular defense mechanism against the activity of foreign genes in an established genome. Pursuing this concept, we have asked for the most likely portal of entry of foreign DNA, supposedly the gastrointestinal tract in most animals. This hypothesis has been tested by feeding mice linearized or circular, double-stranded bacteriophage M13mp18 DNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative and qualitative characterization of apolipoprotein B containing lipoproteins produced by the visceral rat yolk sac in two different in vitro systems: organ culture and isolated epithelial cells in suspension culture

Tissue pieces as well as isolated epithelial cells taken from visceral rat yolk sacs at the 18th day of gestation were able to synthesize and to secrete apo B containing lipoproteins floating in the density ranges of VLDL, IDL and LDL. In all three density classes only the high molecular weight apo B was detectable. VLDL secreted from yolk sac tissue or isolated epithelial cells lacked apo E and apo C. Studies with cycloheximide revealed that about 77% of the particles was delivered from a pool of preformed lipoproteins. Evidence was given that also de novo-synthesis of apo B containing lipoproteins took place in the tissue segments and the isolated epithelial cells. Most of apo B mass (90%) and of apo B radioactivity (60%) secreted by the tissue pieces of the visceral yolk sac floated in the density range 1.020-1.064 g/ml, the remainder being found in the d < or = 1.020 g/ml fraction. In contrast, only 40% of apo B mass and 45% of apo B radioactivity delivered from isolated epithelial cells belonged to the d = 1.020-1.064 g/ml fraction. LDL released from yolk sacs and isolated epithelial cells contained more triacylglycerols (41% vs. 25%) and had a larger mean diameter (24 nm vs. 21.8 nm) than those obtained from fetal rat serum, whereas the comparatively small VLDL produced in vitro (mean diameter = 34 nm) contained less triacylglycerols (46% vs. 60.5%) and more protein (20% vs. 10.2%) in comparison with fetal serum VLDL (mean diameter = 42.3 nm). Incubation experiments with [125I]VLDL led to the conclusion that the lipase secreted by yolk sac tissue into the medium could not be responsible for the conversion of VLDL into LDL, thus supporting our view of a direct LDL secretion by visceral rat yolk sacs.

The cyclosome, a large complex containing cyclin-selective ubiquitin ligase activity, targets cyclins for destruction at the end of mitosis

The ubiquitin-mediated degradation of mitotic cyclins is required for cells to exit from mitosis. Previous work with cell-free systems has revealed four components required for cyclin-ubiquitin ligation and proteolysis: a nonspecific ubiquitin-activating enzyme E1, a soluble fraction containing a ubiquitin carrier protein activity called E2-C, a crude particulate fraction containing a ubiquitin ligase (E3) activity that is activated during M-phase, and a constitutively active 26S proteasome that degrades ubiquitinated proteins. Here, we identify a novel approximately 1500-kDa complex, termed the cyclosome, which contains a cyclin-selective ubiquitin ligase activity, E3-C. E3-C is present but inactive during interphase; it can be activated in vitro by the addition of cdc2, enabling the transfer of ubiquitin from E2-C to cyclin. The kinetics of E3-C activation suggest the existence of one or more intermediates between cdc2 and E3-C. Cyclosome-associated E3-C acts on both cyclin A and B, and requires the presence of wild-type N-terminal destruction box motifs in each cyclin. Ubiquitinated cyclins are then rapidly recognized and degraded by the proteasome. These results identify the cyclosome-associated E3-C as the component of the cyclin destruction machinery whose activity is ultimately regulated by cdc2 and, as such, the element directly responsible for setting mitotic cyclin levels during early embryonic cell cycles.

Dependency of overall fractionation effect of respiration on hemoglobin concentration within blood at rest

In this study it was investigated in which way varying hemoglobin concentrations within blood influence overall fractionation effect of respiration, meaning a change in composition of isotopic oxygen molecules 16O2 and 16O18O within oxygen transported during entire respiration. Since overall fractionation effect of respiration is known to consist of different fractionating and non-fractionating processes, measuring it under condition of anemia could be useful in relating changes in isotopic compositions of oxygen to limitations of entire oxygen transport caused by one or more of these processes. Experiments were performed on 6 patients suffering from various degrees of anemia of a variety of etiologies and on 6 healthy humans. All test subjects breathed air at rest. Samples from inspiratory and expiratory gas were taken in order to analyse 16O18O/16O2 ratios with the aid of respiratory mass spectrometry. Values of overall fractionation effect decreased with respect to a drop in hemoglobin concentration from 17.6 to 6.6 g/100 ml in terms of a linear relationship (r = 0.79) provided that values of overall fractionation effect were normalized so as to exclude the influence of varying ventilatory conditions. It could be shown that at a value of hemoglobin content of 6.6 g/100 ml, 16O2 was transported in preference to 16O18O with a 0.57% higher rate compared to a value of 0.78% obtained at a hemoglobin concentration of 17.6 g/100 ml.(ABSTRACT TRUNCATED AT 250 WORDS)