An examination of uranium levels in Canadian forces personnel who served in the Gulf War and Kosovo

A uranium bioassay program was conducted involving 103 active and retired Canadian Forces personnel. The total uranium concentrations in each of two 24-h urine collections were analyzed separately at independent commercial laboratories by inductively coupled plasma mass spectrometry (ICP-MS) and by instrumental neutron activation analysis (INAA). The mean and median concentrations were determined to be 4.5 ng L(-1) and 2.8 ng L(-1), respectively, from ICP-MS and 17 ng L(-1) and 15 ng L(-1), respectively, from INAA. The total uranium concentrations were sufficiently low so that isotopic (238U:235U ratio) assays could not be performed directly from urine samples. Isotopic assays were performed on hair samples from 19 of the veterans participating in the testing. The isotopic hair assays were scattered around the natural 238U:235U ratio of 137.8, ranging from 122 +/- 21 to 145 +/- 16 (1sigma). Due to concern expressed in the media over possible depleted uranium exposure and long-term retention in bone, a single bone sample (vertebrate bone marrow) from a deceased member of the Canadian Forces was also analyzed for total uranium content and isotopic ratio by ICP-MS. The sample was shown to have 16.0 +/- 0.3 microg kg(-1) uranium by dry weight and a 238U:238U isotopic ratio of 138 +/- 4, consistent with natural uranium.

Low prevalence of Epstein-Barr virus in incident gastric adenocarcinomas from the United Kingdom

Epstein-Barr virus has been associated with a proportion of typical gastric adenocarcinomas. Here we report that the prevalence of Epstein-Barr virus in gastric adenocarcinomas from the United Kingdom is one of the lowest in the World. Gastric adenocarcinoma is another tumour whose association with Epstein-Barr virus varies with the population studied.

Complete genome sequence of Salmonella enterica serovar Typhimurium LT2

Salmonella enterica subspecies I, serovar Typhimurium (S. typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever. The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year. Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S. typhimurium strain LT2. The distribution of close homologues of S. typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S. enterica serovar Paratyphi A (S. paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S. typhimurium LT2 genes. Lateral transfer of genes is frequent, with 11% of the S. typhimurium LT2 genes missing from S. enterica serovar Typhi (S. typhi), and 29% missing from Escherichia coli K12. The 352 gene homologues of S. typhimurium LT2 confined to subspecies I of S. enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis. Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.

Depressive symptoms in patients with Alzheimer's disease

OBJECTIVES

A comparison was made between the depressive symptom profiles of thirty patients with Alzheimer's disease (AD) who did not have co-existing depression and thirty patients with major depression who did not have co-existing dementia. The main objective was to identify symptoms common to both disorders and those which may be able to differentiate AD from major depression.

METHOD

A sample of patients suffering from either AD (n = 30) or major depression (n = 30) were recruited from a specialist old age psychiatry service. Depressive symptoms were profiled using the Hamilton Depression Rating Scale (HDRS), the Cornell Scale for Depression in Dementia (CSDD) and the Geriatric Depression Scale (GDS).

RESULTS

Depressive symptoms were present in AD in the absence of coexistent major depression. Certain depressive symptoms from all the three scales such as sadness, diurnal variation in mood and early or late insomnia were able to differentiate the two disorders with almost 90% accuracy while symptoms such as irritability, retardation and weight loss were common to both and were unable to differentiate the two.

CONCLUSION

Depressive symptoms occur in AD when co-existing depression is ruled out. Their recognition has implications for the diagnosis of major depression in these patients.

Development and validation of the Conflict in Adolescent Dating Relationships Inventory

Four studies examined the Conflict in Adolescent Dating Relationships Inventory (CADRI), a measure of abusive behavior among adolescent dating partners. Exploratory factor analysis was used to refine items based on high school participants with dating experience (N = 393; 49% female). Confirmatory factor analysis was used to derive and cross-validate the factor structure with participants from 10 high schools (N = 1,019, 55% female; ages 14-16). The model structure fit for all grades and both sexes, with physical abuse, verbal abuse, and threatening behavior most representative of the underlying "abuse" factor. In Studies 3 and 4, the second-order abuse factor showed acceptable test-retest reliability, partner agreement, and correlation (significant for males only) between observer ratings of dating partners' interactions and youths' CADRI scores. Results support the CADRI as a measure of abusive behavior in adolescent dating relationships.

A chemosensory gene family encoding candidate gustatory and olfactory receptors in Drosophila

A novel family of candidate gustatory receptors (GRs) was recently identified in searches of the Drosophila genome. We have performed in situ hybridization and transgene experiments that reveal expression of these genes in both gustatory and olfactory neurons in adult flies and larvae. This gene family is likely to encode both odorant and taste receptors. We have visualized the projections of chemosensory neurons in the larval brain and observe that neurons expressing different GRs project to discrete loci in the antennal lobe and subesophageal ganglion. These data provide insight into the diversity of chemosensory recognition and an initial view of the representation of gustatory information in the fly brain.

Child maltreatment: risk of adjustment problems and dating violence in adolescence

OBJECTIVE

To examine the relationship between child maltreatment, clinically relevant adjustment problems, and dating violence in a community sample of adolescents.

METHOD

Adolescents from 10 high schools (N= 1,419; response rate = 62%) in southwestern Ontario completed questionnaires that assessed past maltreatment, current adjustment, and dating violence. Logistic regression was used to compare maltreated and nonmaltreated youths across outcome domains.

RESULTS

One third (n = 462) of the school sample reported levels of maltreatment above the cutoff score on the Childhood Trauma Questionnaire. Girls with a history of maltreatment had a higher risk of emotional distress compared with girls without such histories (e.g., odds ratios [OR] for anger, depression, anxiety, and posttraumatic stress-related problems were 7.1, 7.2, 9.3, and 9.8, respectively). They were also at greater risk of violent and nonviolent delinquency (OR = 2.7) and carrying concealed weapons (OR = 7.1). Boys with histories of maltreatment were 2.5 to 3.5 times as likely to report clinical levels of depression, posttraumatic stress, and overt dissociation as were boys without a maltreatment history. They also had a significantly greater risk of using threatening behaviors (OR = 2.8) or physical abuse (OR = 3.4) against their dating partners.

CONCLUSIONS

Maltreatment is a significant risk factor for adolescent maladjustment and shows a differential pattern for male and female adolescents.

A comparison of scoring weights for the EuroQol derived from patients and the general public

OBJECTIVE

General health state classification systems, such as the EuroQol instrument, have been developed to improve the systematic measurement and comparability of health state preferences. In this paper we generate valuations for EuroQol health states using responses to this instrument's visual analogue scale made by patients enrolled in a randomized clinical trial evaluating tirilazad mesylate, a new drug used to treat subarachnoid haemorrhage. We then compare these valuations derived from patients with published valuations derived from responses made by a sample from the general public.

METHODS

The data were derived from two sources: (1) responses to the EuroQol instrument from 649 patients 3 months after enrollment in the clinical trial, and (2) from a published study reporting a scoring rule for the EuroQol instrument that was based upon responses made by the general public. We used a linear regression model to develop an additive scoring rule. This rule enables direct valuation of all 243 EuroQol health states using patients' scores for their own health states elicited using a visual analogue scale. We then compared predicted scores generated using our scoring rule with predicted scores derived from a sample from the general public.

RESULTS

The predicted scores derived using the additive scoring rules met convergent validity criteria and explained a substantial amount of the variation in visual analogue scale scores (R(2)=0.57). In the pairwise comparison of the predicted scores derived from the study sample with those derived from the general public, we found that the former set of scores were higher for 223 of the 243 states. Despite the low level of correspondence in the pairwise comparison, the overall correlation between the two sets of scores was 87%.

CONCLUSIONS

The model presented in this paper demonstrated that scoring weights for the EuroQol instrument can be derived directly from patient responses from a clinical trial and that these weights can explain a substantial amount of variation in health valuations. Scoring weights based on patient responses are significantly higher than those derived from the general public. Further research is required to understand the source of these differences.

Analysis of grape ESTs: global gene expression patterns in leaf and berry

Analysis of 2479 ESTs from Vitis vinifera berry tissue and 2438 from leaf revealed that 1% of the ESTs match to known Vitis proteins, 72% to plant proteins, 11% to non-plant, and 16% had no match (P[N]>0.5). The levels of redundancy were similar in the leaf and berry libraries. Only 12% of the genes matched by the ESTs were common to both libraries indicating marked differences in the genes expressed in the two tissues. The abundance of transcripts with predicted cellular roles in leaf and berry were estimated by classifying the primary BLAST matches to known proteins (score >80) into functional categories. Thirty-six percent of the leaf transcripts were involved in photosynthesis, compared to 3% in the berry. This is a much higher proportion of transcripts involved with a function limited to specialized cells, than was found when transcripts of 33 human tissues were compared using a similar approach, suggesting plant cells may involve their cellular machinery to a greater extent in specialized activities than animal cells. Relatively enhanced expression of specific transcription factors, and genes involved in defense, detoxification, stress response, proteolysis, trafficing, and signal transduction, suggests berry tissue is actively engaged in responding to environmental stimuli.

Effects of cricket ball colour and illuminance levels on catching behaviour in professional cricketers

In recent years there have been many alterations to equipment and technology in professional cricket, including the introduction of white balls during day-night matches. In the present study simulated slip-catching performance and movement initiation time were examined in professional cricketers when ball colour and illuminance levels differed. Five male professional cricketers (mean age: 27.3 +/- 1.4 years) volunteered to catch a total of 60 cricket balls, 20 (10 red and 10 white) under each of three illuminance levels (571, 1143 and 1714 lux). Balls were projected from a ball machine at 20 m s(-1) (45 mph) over a distance of 8.4 m, to the subject's dominant side. Catching performance was measured using an established catching scale. Movement initiation times for each hand were also calculated for each trial using a motion-analysis system. Data were submitted to separate two-way (ball colour [2] x illuminance level [3]) repeated measures analysis of variance. No significant effects were obtained for ball colour or illuminance levels for either catching performance or movement initiation time. Neither ball colour nor light level (within the range tested) affected slip-catching performance and movement initiation times in professional cricketers. Therefore it was concluded that the changes made to ball colour and light conditions in professional cricket were not detrimental to catching performance.

Assessment of patients with facial fractures

One of the most demanding aspects of emergency medicine is the management of patients who have suffered facial trauma. The diagnosis and initial management of patients who have sustained traumatic facial injuries are discussed. The fundamentals required to assess patients with fractures of the facial skeleton and to make appropriate referrals are provided.

Impaired cued and contextual memory in NPAS2-deficient mice

Neuronal PAS domain protein 2 (NPAS2) is a basic helix-loop-helix (bHLH) PAS domain transcription factor expressed in multiple regions of the vertebrate brain. Targeted insertion of a beta-galactosidase reporter gene (lacZ) resulted in the production of an NPAS2-lacZ fusion protein and an altered form of NPAS2 lacking the bHLH domain. The neuroanatomical expression pattern of NPAS2-lacZ was temporally and spatially coincident with formation of the mature frontal association/limbic forebrain pathway. NPAS2-deficient mice were subjected to a series of behavioral tests and were found to exhibit deficits in the long-term memory arm of the cued and contextual fear task. Thus, NPAS2 may serve a dedicated regulatory role in the acquisition of specific types of memory.

Activity of cecropin P1 and FA-LL-37 against urogenital microflora

Two mammalian antimicrobial peptides, FA-LL-37 and cecropin P1, were tested for activity against six uropathogens and five Lactobacillus strains by broth microdilution assay. Both peptides inhibited Escherichia coli at 25 microM (FA-LL-39), and 1.56 microM (cecropin P1), Pseudomonas aeruginosa (12.5 microM, and 25 microM), and Klebsiella pneumoniae, (50 microM, and 1.56 microM), but not Enterococcus faecalis and Staphylococcus epidermidis. FA-LL-37 acted bacteriocidally against E. coli and bacteriostatically against the other two Gram-negative organisms. Cecropin P1 was bacteriocidal to all susceptible bacteria. Lactobacilli were resistant to both peptides, with the exception of poultry isolate Lactobacillus fermentum B-54, which was susceptible to FA-LL-37 at 100 microM. The differential activities of these peptides toward Gram-negative uropathogens versus urogenital lactobacilli demonstrate their potential as a topical treatment for urinary tract infections. In addition, production of such peptides in vivo could be a natural mechanism to aid in the maintenance of the lactobacilli-dominated urogenital flora at the expense of pathogens.

The ryanodine receptor is essential for larval development in Drosophila melanogaster

We have investigated the role of the ryanodine receptor in Drosophila development by using pharmacological and genetic approaches. We identified a P element insertion in the Drosophila ryanodine receptor gene, Ryanodine receptor 44F (Ryr), and used it to generate the hypomorphic allele Ryr(16). An examination of hypodermal, visceral, and circulatory muscle showed that, in each case, muscle contraction was impaired in Ryr(16) larvae. Treatment with the drug ryanodine, a highly specific modulator of ryanodine receptor channel activity, also inhibited muscle function, and, at high levels, completely blocked hypodermal muscle contraction. These results suggest that the ryanodine receptor is required for proper muscle function and may be essential for excitation-contraction coupling in larval body wall muscles. Nonmuscle roles of Ryr were also investigated. Ryanodine-sensitive Ca(2+) stores had previously been implicated in phototransduction; to address this, we generated Ryr(16) mutant clones in the adult eye and performed whole-cell, patch-clamp recordings on dissociated ommatidia. Our results do not support a role for Ryr in normal light responses.

Variation in the frequency of Epstein-Barr virus-associated Hodgkin's disease with age

A number of studies in developed countries have reported variation in the frequency of Epstein-Barr virus (EBV)-associated Hodgkin's disease (HD) with age. A 'three disease' model for HD that incorporates the EBV association, histological subtype of HD and age has recently been proposed. In this model, Hodgkin's disease of childhood and older adults is commonly EBV-associated and of mixed cellularity type, whereas young adult HD is generally not EBV-associated and is usually characterised by nodular sclerosis disease. A case series of HD diagnosed in the West Midlands between 1981 and 1997, inclusive, was used to investigate the applicability of the 'three disease' model. In situ hybridisation for the EBV early RNAs (EBERs) was used to determine the presence of EBV in the malignant Hodgkin/Reed-Sternberg cells. In contrast to the 'three disease' model, nodular sclerosis was the predominant subtype in each of the age groups within the case series. In addition, overall there was little variation in EBV-positive rates across the age ranges examined. However, when females were analysed separately, older women (45+ years) were significantly more likely to have EBV-positive disease than their younger counterparts (<45 years). In summary our results do not generally support the 'three disease' model.

Long-term cyclophosphamide treatment for recurrent type I membranoproliferative glomerulonephritis after transplantation

The incidence of recurrent type I membranoproliferative glomerulonephritis (MPGN) after renal transplant is approximately 30%, and the rate of graft loss due to recurrent MPGN type I is higher than 50%. The treatment of this disease has not been defined. We report a case of recurrent MPGN type diagnosed 4 months after a cadaveric renal transplantation. The patient was treated with cyclophosphamide and was able to maintain her graft function. Cyclophosphamide was interrupted three times during the course. Each time her renal function deteriorated and her serum albumin decreased. The patient currently has a functional renal graft 3 years after transplantation while receiving low-dose therapy with cyclophosphamide. We suggest treating recurrent type I MPGN with cyclophosphamide while continuing the calcineurin inhibitor and prednisone.

Relation of Bcl-2 expression to androgen receptor, p21WAF1/CIP1, and cyclin D1 status in prostate cancer

BACKGROUND

There is currently no effective treatment for recurrent hormone refractory carcinomas of the prostate gland. An understanding of the underlying mechanisms responsible for the progression of these lesions is likely to be important for the development of new therapeutic approaches. Recently, it has been suggested that the transition to a hormone independent state is accompanied by increased proliferation and bcl-2 gene expression, as well as by a decreased apoptotic state.

AIM

To investigate the possible role of Bcl-2 and other cell cycle regulating proteins in the development of prostatic tumours.

METHODS

Immunohistochemistry was used to study the relation between the expression of Bcl-2 and the androgen receptor, as well as p21WAF1/CIP1 (p21), and cyclin D1 status, in a series of 89 prostate cancer samples taken before androgen withdrawal treatment.

RESULTS

Androgen receptor negative tumours expressed significantly higher amounts of Bcl-2 than those prostate carcinomas with low/medium androgen receptor values. However, in tumours expressing the highest amounts of androgen receptor, Bcl-2 expression was also high. A significant positive relation between Bcl-2 and p21 expression, as well as an inverse relation between Bcl-2 and cyclin D1 expression, was noted. Androgen receptor positive samples also expressed significantly higher amounts of cyclin D1.

CONCLUSIONS

These results suggest that p21 and cyclin D1 expression in prostatic cancer might be modulated by Bcl-2 and by androgens and in turn this could be relevant to the progression of prostatic cancer.

Maintaining carotid flow by shunting during carotid endarterectomy diminishes the inflammatory response mediating ischaemic brain injury

OBJECTIVES

to assess whether shunting during carotid reconstruction affects the release of inflammatory mediators from the ipsilateral hemisphere.

MATERIALS AND METHODS

a catheter was placed in the ipsilateral jugular bulb during carotid endarterectomy (CEA) in 20 patients. Eight patients with ICBP (internal carotid backpressure) <40 mmHg received a shunt during CEA and 12 patients with ICBP >40 mmHg were operated upon without a shunt. Four patients with a carotid body tumour were used as controls. Blood was taken from the catheter as well as from the radial artery; before clamping, 5, 15, 30 min after clamping and 5 min after declamping. The oxygen extraction (AVO(2)) was calculated. Plasma concentrations of interleukin-1beta (IL-1beta), phospholipase A(2)(PLA(2)), thromboxane B(2)(TXB(2)), 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) and prostaglandin E(2)(PGE(2)) were measured by enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

all patients had a normal postoperative course except for one patient in the no-shunt group, who suffered a stroke 1 h later due to occlusion of the endarterectomy site. The AVO(2)extraction increased during clamping in patients operated upon without a shunt (p <0.05). This increase was partly recovered to pre-clamp levels 5 min after reperfusion. The extraction remained stable in the non-shunted patients and the control group. The increased extraction in the non-shunted group correlated with increased levels of IL-1beta during clamping ( p <0.05) and reperfusion ( p <0.01). PLA(2)also increased during reperfusion in the non-shunted group ( p <0.05). An increased ratio between TXB(2)and 6-keto-PGF1alpha was noted during clamping ( p <0.05) and further increased during reperfusion. The levels of PGE(2)remained stable in both CEA groups. The PLA(2)levels, as well as TXB(2), 6-keto-PGF1alpha and PGE(2)levels, remained unchanged during the procedure in the control group.

CONCLUSIONS

there is a metabolic response to carotid cross-clamping when no shunt is used. However, the clinical significance of this is unclear, since there were no intraoperative strokes.

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

Lipase-catalyzed fractionation of conjugated linoleic acid isomers

The abilities of lipases produced by the fungus Geotrichum candidum to selectively fractionate mixtures of conjugated linoleic acid (CLA) isomers during esterification of mixed CLA free fatty acids and during hydrolysis of mixed CLA methyl esters were examined. The enzymes were highly selective for cis-9,trans-11-18:2. A commercial CLA methyl ester preparation, containing at least 12 species representing four positional CLA isomers, was incubated in aqueous solution with either a commercial G. candidum lipase preparation (Amano GC-4) or lipase produced from a cloned high-selectivity G. candidum lipase B gene. In both instances selective hydrolysis of the cis-9,trans-11-18:2 methyl ester occurred, with negligible hydrolysis of other CLA isomers. The content of cis-9, trans-11-18:2 in the resulting free fatty acid fraction was between 94 (lipase B reaction) and 77% (GC-4 reaction). The commercial CLA mixture contained only trace amounts of trans-9,cis-11-18:2, and there was no evidence that this isomer was hydrolyzed by the enzyme. Analogous results were obtained with these enzymes in the esterification in organic solvent of a commercial preparation of CLA free fatty acids containing at least 12 CLA isomers. In this case, G. candidum lipase B generated a methyl ester fraction that contained >98% cis-9,trans-11-18:2. Geotrichum candidum lipases B and GC-4 also demonstrated high selectivity in the esterification of CLA with ethanol, generating ethyl ester fractions containing 96 and 80%, respectively, of the cis-9,trans-11 isomer. In a second set of experiments, CLA synthesized from pure linoleic acid, composed essentially of two isomers, cis-9,trans-11 and trans-10,cis-12, was utilized. This was subjected to esterification with octanol in an aqueous reaction system using Amano GC-4 lipase as catalyst. The resulting ester fraction contained up to 97% of the cis-9,trans-11 isomer. After adjustment of the reaction conditions, a concentration of 85% trans-10,cis-12-18:2 could be obtained in the unreacted free fatty acid fraction. These lipase-catalyzed reactions provide a means for the preparative-scale production of high-purity cis-9,trans-11-18:2, and a corresponding CLA fraction depleted of this isomer.

Effect of Epstein-Barr virus infection on response to chemotherapy and survival in Hodgkin's disease

We have analyzed paraffin sections from 190 patients with histologically confirmed Hodgkin's disease (HD) for the presence of Epstein-Barr virus (EBV) using in situ hybridization to detect the EBV-encoded Epstein-Barr virus early RNAs (EBERs) and immunohistochemistry to identify latent membrane protein-1 (LMP1) expression. EBV was present in the tumor cells in 51 HD cases (27%) and was mainly confined to the mixed cellularity and nodular sclerosis subtypes. There was no difference between EBV-positive and EBV-negative HD patients with regard to age, clinical stage, presentation, and the number of alternating chemotherapy cycles of ChIVPP and PABIOE received. The complete remission rate after study chemotherapy was 80% in EBV-positive patients versus 69% in EBV-negative patients (P =.05). The 2-year failure-free survival rate was significantly better for EBV-positive patients when compared with the EBV-negative HD group (P =.02). Although 2-year and 5-year overall survival rates were better for EBV-positive HD patients, the differences were not statistically significant (P =.18 and P =.40, respectively). In conclusion, the results confirm the favorable prognostic value of EBV in the tumor cells of HD patients and suggest important differences in response to chemotherapy between EBV-positive and EBV-negative patients.

TCR-mediated involvement of CD4+ transgenic T cells in spontaneous inflammatory bowel disease in lymphopenic mice

Spontaneous colitis resembling ulcerative colitis developed in 3 of 10 independent TCR transgenic (Tg) mouse lines maintained under specific pathogen-free conditions. All three susceptible lines were CD4 lymphopenic, whereas resistant lines had normal numbers of CD4+ T cells. Thus, cytochrome c-specific 5C.C7 TCR Tg mice developed colitis only when crossed onto a SCID- or Rag-1-deficient background. A second line of lymphopenic cytochrome c-specific Tg mice bearing the AND TCR also developed colitis. In both cases, CD4+ T cells expressing the Tg-encoded TCR were preferentially activated in inflamed colons compared with lymph nodes or spleens. In contrast, Tg+CD4+ T cells remained quiescent in both inflamed and unaffected colons in another line of susceptible Tg mice carrying a TCR specific for myelin basic protein, suggesting a fortuitous cross-reactivity of the IEk-restricted cytochrome c-reactive AND and 5C.C7 TCRs with an Ag present in the gut. The percentage of CD4+ T cells expressing only endogenous TCR alpha-chains was increased consistently in inflamed colons in AND as well as 5C.C7 Rag-1-/- TCR Tg mice, suggesting that polyclonal CD4+ T cells were also involved in the pathogenesis of spontaneous colitis. Moreover, our data indicate that some alpha-chain rearrangement was still occurring in TCR Tg mice on a Rag-1-/- background, since activated CD4+ T cells expressing endogenously rearranged alpha-chains paired with the Tg-encoded beta-chain were detected consistently in the colons of such mice.