Ulcerative proctitis is a frequent location of paediatric-onset UC and not a minor disease: a population-based study

OBJECTIVE

Natural history of paediatric-onset ulcerative proctitis (UP) is poorly described. Our aim was to describe the phenotype and disease course of incident UP in a population-based study of paediatric-onset UC.

PATIENTS AND METHODS

All patients with UC diagnosed <17 years from 1988 to 2004, and followed during >2 years have been extracted from a population-based registry. UC location was defined according to the Paris classification. Cumulative risks for use of immunosuppressants (IS), anti-tumour necrosis factor alpha (TNF-α) therapy, colonic extension and colectomy were described using Kaplan-Meier method. Risk factors for colonic extension were assessed using Cox proportional hazards models.

RESULTS

158 patients with paediatric-onset UC (91 females) with a median age at diagnosis of 14.5 years (Q1: 11.4-Q3: 16.1) have been identified and followed during a median of 11.4 years (8.2-15.8). Among them, 25% had UP (E1) at diagnosis and 49% of them presented a colonic extension at maximal follow-up. In these children, the cumulative risk for colonic extension was 10% at 1 year, 45% at 5 years and 52% at 10 years. No parameter at diagnosis was associated with colonic extension in the UP (E1 group). IS use was significantly lower in patients with UP than in those with E2, E3 or E4 location (p=0.049). For the UP cohort, the cumulative risk for colectomy was 3% at 1 year, 10% at 5 years, 13% at 10 years and 13% at 15 years. Risks for colonic extension, treatment with anti-TNF-α and colectomy did not differ between the E1 group and the E2-E3-E4 group.

CONCLUSIONS

UP is frequent in paediatric-onset UC and should not be considered as a minor disease. Compared with more extensive UC locations, risks for colonic extension, anti-TNF-α therapy and colectomy were similar in UP, whereas the risk for use of IM was lower.

Incidence and Phenotype at Diagnosis of Very-early-onset Compared with Later-onset Paediatric Inflammatory Bowel Disease: A Population-based Study [1988-2011]

BACKGROUND AND AIMS

Very-early-onset inflammatory bowel disease [VEO-IBD] is a form of IBD that is distinct from that of children with an older onset. We compared changes over time in the incidence and phenotype at diagnosis between two groups according to age at IBD diagnosis: VEO-IBD diagnosed before the age of 6 years, and early-onset IBD [EO-IBD] diagnosed between 6 and 16 years of age.

METHODS

Data were obtained from a cohort enrolled in a prospective French population-based registry from 1988 to 2011.

RESULTS

Among the 1412 paediatric cases [< 17 years], 42 [3%] were VEO-IBD. In the VEO-IBD group, the incidence remained stable over the study period. In contrast, the incidence of EO-IBD increased from 4.4/105 in 1988-1990 to 9.5/105 in 2009-2011 [+116%; p < 10-4]. Crohn's disease [CD] was the most common IBD, regardless of age, but ulcerative colitis [UC] and unclassified IBD were more common in VEO-IBD cases [40% vs 26%; p = 0.04]. VEO-IBD diagnosis was most often performed in hospital [69% vs 43%; p < 10-3]. Rectal bleeding and mucous stools were more common in patients with VEO-IBD, whereas weight loss and abdominal pain were more frequent in those with EO-IBD. Regarding CD, isolated colonic disease was more common in the VEO-IBD group [39% vs 14%; p = 0.003].

CONCLUSIONS

In this large population-based cohort, the incidence of VEO-IBD was low and stable from 1988 to 2011, with a specific clinical presentation. These results suggest a probable genetic origin for VEO-IBD, whereas the increase in EO-IBD might be linked to environmental factors.

Usability Flaws in Medication Alerting Systems: Impact on Usage and Work System

OBJECTIVES

Previous research has shown that medication alerting systems face usability issues. There has been no previous attempt to systematically explore the consequences of usability flaws in such systems on users (i.e. usage problems) and work systems (i.e. negative outcomes). This paper aims at exploring and synthesizing the consequences of usability flaws in terms of usage problems and negative outcomes on the work system.

METHODS

A secondary analysis of 26 papers included in a prior systematic review of the usability flaws in medication alerting was performed. Usage problems and negative outcomes were extracted and sorted. Links between usability flaws, usage problems, and negative outcomes were also analyzed.

RESULTS

Poor usability generates a large variety of consequences. It impacts the user from a cognitive, behavioral, emotional, and attitudinal perspective. Ultimately, usability flaws have negative consequences on the workflow, the effectiveness of the technology, the medication management process, and, more importantly, patient safety. Only few complete pathways leading from usability flaws to negative outcomes were identified.

CONCLUSION

Usability flaws in medication alerting systems impede users, and ultimately their work system, and negatively impact patient safety. Therefore, the usability dimension may act as a hidden explanatory variable that could explain, at least partly, the (absence of) intended outcomes of new technology.

Two Caucasian Families with the Hepatocyte Nuclear Factor-1Alpha Mutation Tyr218Cys

We report on the first two Caucasian families with the MODY3 HNF-1alpha mutation Tyr218Cys. Clinical and laboratory examinations are shown in detail. Patients with HNF-1alpha related MODY may develop the full spectrum of diabetic complications. Therefore, early detection of family members with MODY3 is warranted.

Haplotypes in the promoter region of the ADIPOQ gene are associated with increased diabetes risk in a German Caucasian population

Adiponectin, which is encoded by the ADIPOQ gene, has been shown to modulate insulin sensitivity and glucose homeostasis. Plasma adiponectin levels are decreased in type 2 diabetes and obesity. Genetic variations within the ADIPOQ gene are associated with decreased adiponectin hormone levels. To analyze specific single-nucleotide polymorphisms (SNPs) and their association with T2D, 365 German subjects with T2D and 323 control subjects were screened. Three common SNPs - +45T>G in exon 2, and 2 promoter variants SNPs -11391G>A and -11377C>G - were analyzed. We found that the variant allele of SNP -11391G>A was significantly more frequent in the diabetic patient group than in the control group (p=0.003). Carrying the haplotype of SNP -11391A and SNP -11377C was associated with a 1.50-fold (p=0.03) increase in diabetes risk. The combination of the A-C haplotype and the G-C haplotype was associated with significantly elevated diabetes risk (OR=2.82 (95% CI: 1.35-5.91), p=0.006) after correction for BMI and age. Our observations suggest that diploid combinations of haplotype in the adiponectin gene promoter region contribute to the genetic risk of T2D in individuals from a German Caucasian population.

Hypoadiponectinaemia and high risk of type 2 diabetes are associated with adiponectin-encoding (ACDC) gene promoter variants in morbid obesity: evidence for a role of ACDC in diabesity

AIMS/HYPOTHESIS

Morbid obesity (BMI>40 kg/m(2)) affecting 0.5-5% of the adult population worldwide is a major risk factor for type 2 diabetes. We aimed to elucidate the genetic bases of diabetes associated with obesity (diabesity), and to analyse the impact of corpulence on the effects of diabetes susceptibility genes.

METHODS

We genotyped known single nucleotide polymorphisms (SNPs) in the adiponectin-encoding adipocyte C1q and collagen-domain-containing (ACDC) gene (-11,391G>A, -11,377C>G, +45T>G and +276G>T), the peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala SNP and ACDC exon 3 variants in 703 French morbidly obese subjects (BMI 47.6+/-7.4 kg/m(2)), 808 non-obese subjects (BMI<30 kg/m(2)) and 493 obese subjects (30< or =BMI<40 kg/m(2)).

RESULTS

Two 5'-ACDC SNPs -11,391G>A, -11,377C>G were associated with adiponectin levels (p=0.0003, p=0.008) and defined a "low-level" haplotype associated with decreased adiponectin levels (p=0.0002) and insulin sensitivity (p=0.01) and with a risk of type 2 diabetes that was twice as high (p=0.002). In contrast, the prevalence of the PPARG Pro12Ala was identical in diabetic and normoglycaemic morbidly obese subjects. The PPARG Pro12 allele only displayed a trend of association with type 2 diabetes in the non-obese group. ACDC exon 3 variants were associated with type 2 diabetes in the non-obese group only (odds ratio 7.85, p<0.0001). In contrast, the 5'-ACDC "low-level" haplotype was associated with type 2 diabetes in obese and morbidly obese subjects (odds ratio 1.73 and 1.92) but not in non-obese individuals.

CONCLUSIONS/INTERPRETATION

These data clarify the contribution of the 5'-ACDC SNPs to the risk of diabesity. Their interaction with corpulence suggests for the first time a different genetic profile of type 2 diabetes in morbidly obese patients compared with in less obese individuals.

Genetic study of the CD36 gene in a French diabetic population

OBJECTIVES

CD36 is a multifunctional membrane receptor widely expressed in different tissues which binds and internalizes oxidized low-density lipoprotein. In rodents, CD36 gene variations modulate glucose homeostasis and contribute to metabolic syndrome associated with type 2 diabetes but the effects in human are unknown.

METHODS

We screened the entire coding sequence of the CD36 gene in 272 individuals and we genotyped both rare and frequent variants in 454 T2D subjects and 221 controls.

RESULTS

We detected five mutations, P191P and N247S were only found each in one family and did not segregate with diabetes, the three others (A/C-178 in the promoter, A/G-10 in intron 3 and (GGGTTGAGA) insertion in intron 13) being equally frequent in diabetic subjects and in controls. However, adiponectin levels, a marker for insulin sensitivity, were significantly associated with the -178 A/C promoter variant allele (p=0.003, p corrected for multiple testing=0.036), possibly reflecting association with insulin-resistance in the French population.

CONCLUSION

Thus, the -178 A/C SNP promoter mutation in the CD36 gene represents a putative genetic marker for insulin-resistance in the French population, although it does not appear to contribute to the genetic risk for T2D.

Dissection of an inverted X(p21.3q27.1) chromosome associated with mental retardation

In a 6 year old boy referred for mental retardation, fragile X syndrome was ruled out by cytogenetic and molecular analyses. Cytogenetic investigations revealed an inverted X chromosome (p21.3q27.1). A similar chromosomal rearrangement was detected in his mildly mentally retarded mother. Fluorescence in situ hybridization (FISH), using a panel of ordered YAC clones, allowed the identification of YACs spanning both the Xp21.3 and Xq27.1 breakpoints, where many non-specific mental retardation loci have been reported so far. Further investigations by FISH showed that the IL1RAPL1 gene at Xp21.3 was disrupted by the X chromosome inversion and therefore its inactivation may be related to the mental retardation observed in our patients.

Molecular and cytogenetic characterisation of a small interstitial de novo 20p13-->p12.3 deletion in a patient with severe growth deficit

We report on a small de novo interstitial deletion of the short arm of chromosome 20, 46,XY,del(20)(p12.3p13), in a young boy with hypotonia, moderate development delay, mild facial dysmorphism and severe growth failure. This patient did not show major features of Alagille-Watson Syndrome (AWS) which are common in more proximal 20p deletions. Standard and high resolution chromosome banding analysis revealed an apparent terminal deletion. Nevertheless, using chromosomal fluorescent in situ hybridization (FISH) and molecular analysis with polymorphic markers, we demonstrated that the abnormal chromosome resulted from a de novo interstitial deletion of paternal origin spanning from D20S842 to D20S900 and covering approximately 6 Mb. These findings indicate that a karyotype can lead to insufficient characterization of an apparently terminal deletion, and that one or a few genes in 20p13-->p12.3 bands are important for normal growth.

Mutation screening of the urocortin gene: identification of new single nucleotide polymorphisms and association studies with obesity in French Caucasians

A linkage between obesity-related phenotypes and the 2p21-23 locus has been reported previously. The urocortin (UCN) gene resides at this interval, and its protein decreases appetite behavior, suggesting that UCN may be a candidate gene for susceptibility to obesity. We localized the UCN gene by radiation hybrid mapping, and the surrounding markers were genotyped in a collection of French families. Evidence for linkage was shown between the marker D2S165 and leptin levels (LOD score, 1.34; P = 0.006) and between D2S2247 and the z-score of body mass index (LOD score, 1.829; P = 0.0019). The gene was screened for SNPs in 96 obese patients. Four new variants were established. Two single nucleotide polymorphisms were located in the promoter (-535 A-->G, -286 G-->A), one in intron 1 (+31 C-->G), and one in the 3'-untranslated region (+34 C-->T). Association studies in cohorts of 722 unrelated obese and 381 control subjects and transmission disequilibrium tests, performed for the two frequent promoter polymorphisms, in 120 families (894 individuals) showed that no association was present between these variants and obesity, obesity-related phenotypes, and diabetes. Thus, our analyses of the genetic variations of the UCN gene suggest that, at least in French Caucasians, they do not represent a major cause of obesity.

Scheduled kinetics of cell proliferation and phenotypic changes during immature thymocyte generation

Precursor CD4-CD8- (DN) thymocytes rearrange their TCR-beta genes, and only those which succeed in beta-selection subsequently expand and differentiate into immature CD4+CD8+ (DP) thymocytes. The cell subsets corresponding to the successive steps of this transition can be defined in terms of CD44 and CD25 expression. We partially synchronized the differentiation process by eliminating cycling cells with the anti-mitotic agent demecolcine. Using in vivo pulse labeling with bromodeoxyuridine, we determined the order of entry into DNA synthesis of the different DN and transitory (CD4-/lo CD8+) cell subsets. Two independent proliferation phases were identified. The first cells to enter the cell cycle were CD44-CD25lo, and CD4/CD8/TCR-/BrdU four-color staining showed that they all expressed a low density of the TCR-beta chain, an element of the pre-TCR (the TCR-alpha locus is still in germ-line configuration at this stage). Cycling of CD44+CD25+ cells was detected later, and no starting point was observed at the CD44-CD25hi stage. CD8 expression was immediately detectable in cycling cells, but they took 24 h to reach the DP stage. The study of TCR-Calpha-deficient mice showed that beta gene rearrangement occurred once proliferation had ceased at the DP stage, and that it had no influence on the DN-DP transition. These data show that precursor thymocytes undergo two independent waves of expansion, and that the second wave is restricted to cells capable of pre-TCR expression.

Routine mutation screening of HNF-1alpha and GCK genes in MODY diagnosis: how effective are the techniques of DHPLC and direct sequencing used in combination?

AIMS/HYPOTHESIS

Mutations in the hepatocyte nuclear factor (HNF)-1alpha and glucokinase (GCK) genes are the major causes of monogenic forms of Type II (non-insulin-dependent) diabetes mellitus (Maturity-Onset Diabetes of the Young subtypes, MODY). We evaluated the effectiveness of fluorescent single-strand conformation polymorphism (F-SSCP), denaturing high-performance liquid chromatography (DHPLC) and sequencing based mutation detection in the molecular diagnosis of MODY. Our goal is to identify a rapid, efficient and cost effective mutation detection method for the molecular diagnosis of MODY and other human genetic disorders.

METHODS

We evaluated the accuracy of DHPLC in screening for MODY 2 and 3 mutations. In addition, we compared the sensitivity, specificity, cost, handling time and analysis time of fluorescent single-strand conformation polymorphism, denaturing high-performance liquid chromatography and direct sequencing screening methods.

RESULTS

Denaturing high-performance liquid chromatography is a recently developed method for mutation detection. It is cost effective, powerful and reliable and quite suitable for 22 out of the 24 fragments required for MODY 2 and 3 testing. However, exons 1 and 7 of the HNF-1alpha gene are very polymorphic and so direct sequencing is faster as well as more efficient and reliable.

CONCLUSION/INTERPRETATION

Our results suggest that combining denaturing high-performance liquid chromatography and direct sequencing is a good approach for the routine detection of HNF-1alpha and GCK mutations in MODY families. Denaturing high-performance liquid chromatography appears to be a powerful tool in genetic testing and the method could be applied to the molecular diagnosis of other human genetic diseases.

Linkage and association studies between the proopiomelanocortin (POMC) gene and obesity in caucasian families

AIMS/HYPOTHESIS

The region 2p21-23, containing the proopiomelanocortin gene (POMC), was reported to be linked to leptin concentrations in Mexican-American, French and African-American cohorts. A polyhormone peptide, POMC is expressed in brain, gut, placenta and pancreas. The POMC mutations are responsible for rare cases of early-onset obesity. Thus we examined the contribution of the POMC locus to obesity in French families.

METHODS

Single and multipoint linkage studies were done between obesity, obesity associated-phenotypes (leptin values and z-score of the body mass index) and three newly mapped markers surrounding POMC in 264 affected sib-pairs from French obese families. Mutation screening of the exons and intron/exon junctions of the POMC gene was realised by direct sequencing. Association studies were done in 379 unrelated obese patients and 370 non-obese non-diabetic subjects.

RESULTS

Linkage analysis confirmed the trend towards linkage between polymorphic markers around POMC and variations of leptin concentrations and z-score (maximum lod score at D2S2337 = 2.03). Mutation screening of the POMC gene in the French Caucasian cohort identified two previously reported polymorphisms. None of these variants was associated with obesity, diabetes or serum leptin and lipid concentrations.

CONCLUSION/INTERPRETATION

Our results indicate that mutations in the POMC gene do not contribute to the variance of obesity associated phenotypes, at least in French Caucasians. Given the replicated evidence of linkage between leptin values and the chromosome 2p21-23 region in different populations, it is likely that functional variant(s) in the POMC regulating sequences or in an unknown gene in this region explains this linkage.

An uncoupling protein 3 gene polymorphism associated with a lower risk of developing Type II diabetes and with atherogenic lipid profile in a French cohort

AIMS/HYPOTHESIS

The UCP2-UCP3 gene region has been previously associated with obesity and diabetes. In a large representative cohort of Northern France (MONICA project), we studied the effect of a recently reported C/T polymorphism located in the 5' sequences of the UCP3 gene on anthropometric measurements and lipid profile. We also examined the association of this polymorphism with obesity and Type II (non-insulin-dependent) diabetes mellitus.

METHODS

The -55 C/T polymorphism of the UCP3 gene has been genotyped in 1155 subjects from the MONICA project. Association studies were done with diabetes, obesity and related phenotypes. Results were ascertained in a second cohort of well-characterized Type II diabetic and control subjects.

RESULTS

The variant T allele was associated with a decreased risk of developing Type II diabetes. Frequencies of the T allele were 13.3% compared with 22%, p = 0.04, in the diabetic and control groups, respectively. This observation was confirmed in the second cohort of French Type II diabetic (n = 171) and control (n = 124) subjects: 17.8% compared with 25%, p = 0.03. Moreover, subjects bearing the TT genotype had higher plasma total cholesterol and LDL-cholesterol concentrations (p = 0.0006 and p = 0.001, respectively) than subjects bearing wild or heterozygous genotypes.

CONCLUSION/INTERPRETATION

The UCP3 -55 C/T polymorphism was associated with a higher atherogenic profile and modified the risk for the development of Type II diabetes.

Selective involvement of the Fas (CD95)/Fas ligand pathway in bone marrow B cell progenitors

B lymphocyte generation in bone marrow (BM) compensates for cell loses. The Fas / Fas ligand (FasL) pathway has been implicated in apoptosis of various cell types. Abnormalities of the Fas receptor or of FasL expression are associated with excessive T cell proliferation and autoimmunity. To examine the role of the Fas / FasL system in B cell differentiation, we created double-chimeric mice by transferring both C57BL / 6 (B6)-Fas(+) and lpr-FasL(+) BM cells into RAG-2(- / -) hosts. Equal numbers of stem cells were co-injected into sublethally irradiated recipients, and their progeny were studied by using antibodies directed against the B6-Ly5. 1(+)5.2(+) and lpr-Ly5.1(-)5.2(+) populations. A longitudinal study lasting for up to 6 months revealed that cells of the lpr phenotype dominated the B6 phenotype in the BM, as a result of their active proliferation. Analysis of the B cell compartment showed more lpr than B6 cells among immature HSA(hi)B220(lo) populations. In contrast, the lpr and B6 phenotypes were equally represented among mature B cells. BM transfer to second hosts indicated that B6-derived B cell progenitors were absent from the first host. These data suggest that activation of the Fas / FasL pathway disturbs the early steps of B cell development and might therefore contribute to the onset of autoimmune disorders.

Regulation and kinetics of premigrant thymocyte expansion

Normal mature thymocytes proliferate before emigrating to the periphery, and continuous bromodeoxyuridine labeling showed that more than 30 % of fully mature thymic emigrants have replicated DNA in the 24 h before exit. The percentage of DNA-synthetizing single-positive (SP) thymocytes is transiently augmented during the postnatal period, with peaks on days 2 and 4 for CD4 and CD8 cells, respectively. Similar kinetics were observed in mouse chimeras made by transfer of normal bone marrow cells into RAG-2-deficient mice. These data show that proliferation of mature thymocytes is developmentally regulated. The proliferation peaks (on days 16 and 18 post transfer) observed in simple bone marrow chimeras were abolished when lymph node T cells were mixed with the bone marrow cell inoculum, suggesting that the peripheral pool controls the late thymic expansion. The phenotype of cycling SP thymocytes is atypical: they do not regulate activation and adhesion surface molecules like peripheral activated T cells.

A genetic variation in the 5' flanking region of the UCP3 gene is associated with body mass index in humans in interaction with physical activity

AIMS/HYPOTHESIS

In obese French Caucasian subjects we previously described a silent UCP3 Tyr99Tyr mutation, associated with body mass index. We hypothesised that an unknown polymorphism in the vicinity of the gene could contribute to obesity.

METHODS

Morbidly obese subjects were screened for mutations in 1 kb upstream from the UCP3 gene. Association studies were done between a variant and obesity in 401 morbidly obese and 231 control subjects.

RESULTS

We detected three rare genetic variants and one polymorphism: a +5 G-->A in exon 1, a -155 C-->T, a -439 A insertion and a -55 C-->T located 6 bp from the putative TATA box. This variant was in linkage disequilibrium with the Tyr99Tyr polymorphism. Frequencies of the variant allele at the -55 locus were similar in the obese and control groups (0.23 vs 0.21). The -55 polymorphism was associated with BMI in the obese group (p = 0.0031): BMI was higher in TT than in CC or CT patients. Likewise control subjects with a TT genotype had a higher BMI (p = 0.03). In the obese group, homozygosity for this variant is a risk factor for high BMI (odds ratio: 1:75, p = 0.02). Obese patients were divided into tertiles according to physical activity. In the group with a wild C/C genotype, BMI was negatively associated with physical activity (p = 0.015).

CONCLUSION/INTERPRETATION

The C-->T polymorphism in the 5' sequences of the UCP3 gene might contribute to the corpulence in obese and normal weight subjects and alter the benefit of physical activity. The UCP3 gene can be considered as a gene modifying corpulence.

Increased fetal and extramedullary hematopoiesis in Fas-deficient C57BL/6-lpr/lpr mice

In this study, we examined the consequences of Fas deficiency on hematopoiesis in C57BL/6-lpr/lpr mice. We found a striking extramedullary increase in hematopoietic progenitor cells, comprising erythroid and nonerythroid lineages alike. These modifications preceded the lymphadenopathy, because early progenitors (colony-forming units-spleen [CFU-S] day 8) were already augmented in day-18 fetal livers of the lpr phenotype. Three weeks after birth, CFU-S increased in peripheral blood and spleen and colony-forming cells (CFU-C) began to accumulate 1 to 3 weeks later. Extramedullary myelopoiesis augmented progressively in Fas-deficient mice, reaching a maximum within 6 months. By then, mature and immature myeloid cells had infiltrated the spleen, the liver, and the peritoneal cavity. Similar changes occurred in C57BL/6-gld/gld mice, indicating that they resulted from Fas/FasL interactions. Medullary hematopoiesis was not significantly modified in adult mice of either strain. Yet, the incidence of CFU-S decreased after Fas cross-linking on normal bone marrow cells in the presence of interferon gamma, consistent with a regulatory function of Fas/FasL interactions in early progenitor cell development. These data provide evidence that Fas deficiency can affect hematopoiesis both during adult and fetal life and that these modifications occur independently from other pathologies associated with the lpr phenotype.

Distribution of cycling T lymphocytes in blood and lymphoid organs during immune responses

Proliferation of murine T lymphocytes in blood, lymph nodes, and spleen was studied in four in vivo stimulation systems, using BrdU pulse-labeling of DNA-synthesizing cells. The T cell response to the superantigen Staphylococcus enterotoxin B (SEB) was studied in detail. Vbeta8+ T cells showed a peak of DNA synthesis 16-24 h after SEB injection, and the percentage of BrdU+ CD4 and CD8 T cells was higher in blood than in lymph nodes and spleen. DNA synthesis was preceded by massive migration of Vbeta8+ cells from blood to lymphoid organs, in which the early activation marker CD69 was first up-regulated. SEB-nonspecific Vbeta6+ cells showed minimal stimulation but, when cycling, also expressed a high level of CD69. The other systems studied were injection of the IFN-gamma inducer polyinosinic:polycytidylic acid, infection by the BM5 variants of murine leukemia virus (the causative agent of murine AIDS), and T cell expansion after transfer of normal bone marrow and lymph node cells into recombinase-activating gene-2-deficient mice. In each case, a peak of T cell proliferation was observed in blood. These data demonstrate the extensive redistribution of cycling T cells in the first few hours after activation. Kinetic studies of blood lymphocyte status appear crucial for understanding primary immune responses because cycling and redistributing T lymphocytes are enriched in the circulating compartment.

Excision repair defect in Rothmund Thomson syndrome

Rothmund Thomson syndrome is a rare autosomal recessive skin disorder. The main clinical feature is poikiloderma appearing in early childhood associated with skeletal abnormalities. Early occurrence of malignancies is another relevant feature. Here we describe the clinical features of 2 patients with Rothmund Thomson syndrome who were investigated for the in vitro DNA repair capacities of blood cells following UVC radiation exposure. DNA excision repair, assessed with unscheduled DNA synthesis following UVC exposure, was decreased in both patients. Such a defect might explain the patients' sensitivity to sunlight and the relatively high risk of cancer associated with this syndrome.

Cytogenetics in multiple myeloma: a multicenter study of 24 patients with t(11;14)(q13;q32) or its variant

Twenty-two patients with multiple myeloma (MM) with a classical t(11;14)(q13;q32) and two complex variants also involving 11q13 and 14q32 regions are reported. We show that t(11;14) (q13;q32) is predominantly noticed in stages II and III and never in stage I patients. Translocation (11;14)(q13;q32) is predominantly observed in hypodiploid or pseudodiploid clones associated with total or partial monosomy of chromosome 13 and additional structural changes in chromosome 1. These translocations may be discovered not only in standard cultures (24-48 hours) without stimulation, but also in cytokine-stimulated cultures (granulocyte macrophage colony-stimulating factor and interleukin 6). The t(11;14)(q13;q32) as a primary or secondary event in MM is discussed, because, in one patient, it was only discovered at relapse.

Regulatory CD4 T cells: expression of IL-2R alpha chain, resistance to clonal deletion and IL-2 dependency

We recently characterized a CD4+ T cell population expressing the IL-2R alpha chain (CD25), producing IL-10 and resisting clonal deletion induced by viral superantigen (vSAG) encoded by mouse mammary tumor virus [MMTV(SW)]. We now report that these apoptosis-resistant cells are generated in the thymus but not from the immature CD4+ CD8+ thymocytes. They migrate from the thymus and are found in the periphery from at least the 10th day of life, after which they expand with the same kinetics in normal and MMTV(SW)-infected mice. Their strong capacity for expansion in the periphery makes this population insensitive to thymectomy in adulthood. CD4+ CD25+ cells were totally dependent on exogenous IL-2 for growth in vitro and in vivo, and were missing in IL-2 knockout (KO) mice. The absence of this population and/or an inability to produce IL-10 may be the missing link between IL-2R alpha KO, IL-2 KO and IL-10 KO mice, which all die of inflammatory bowel disease.

Expansion of mature thymocyte subsets before emigration to the periphery

A small population of DNA-synthesizing mature thymocytes could be defined by analyzing cell surface markers and 5-bromo-2'-deoxyuridine (BrdUrd) labeling by four-color cytofluorometry. These cells have a completely mature phenotype (CD4- CD8+ or CD4+ CD8- TCR(high), HSA-, Qa-2(high)) and expand only weakly after BrdUrd incorporation. They recovered immediately in total number and in DNA synthesis rate after treatment with the antimitotic drug demecolcin, thus much faster than immature CD4+ CD8+ thymocytes. These data demonstrate the existence of a late intrathymic expansion phase, independent of that of developing CD4+ CD8+ immature cells, and involving phenotypically mature cells renewed each day. In mixed chimeras prepared by transfer of bone marrow and lymph node cells into RAG-2(-/-) mice, all cycling mature thymocytes were bone marrow derived. They are thus produced in situ and do not correspond to peripheral T cells reentering the thymus. Double FITC/BrdUrd detection showed that a high proportion (10-20%) of recent thymic emigrants were BrdUrd+ just postcycling cells and that around 50% of cycling mature thymocytes are just ready to emigrate to the periphery in the few hours after DNA synthesis. The late intrathymic expansion phase demonstrated here increases the daily thymic cell export by at least 30%. It could play a role in the adjustment of the T cell repertoire before emigration and in the regulation of the thymic cell output into the peripheral T cell pool.

Expansion of mature thymocyte subsets before emigration to the periphery

A small population of DNA-synthesizing mature thymocytes could be defined by analyzing cell surface markers and 5-bromo-2'-deoxyuridine (BrdUrd) labeling by four-color cytofluorometry. These cells have a completely mature phenotype (CD4- CD8+ or CD4+ CD8- TCR(high), HSA-, Qa-2(high)) and expand only weakly after BrdUrd incorporation. They recovered immediately in total number and in DNA synthesis rate after treatment with the antimitotic drug demecolcin, thus much faster than immature CD4+ CD8+ thymocytes. These data demonstrate the existence of a late intrathymic expansion phase, independent of that of developing CD4+ CD8+ immature cells, and involving phenotypically mature cells renewed each day. In mixed chimeras prepared by transfer of bone marrow and lymph node cells into RAG-2(-/-) mice, all cycling mature thymocytes were bone marrow derived. They are thus produced in situ and do not correspond to peripheral T cells reentering the thymus. Double FITC/BrdUrd detection showed that a high proportion (10-20%) of recent thymic emigrants were BrdUrd+ just postcycling cells and that around 50% of cycling mature thymocytes are just ready to emigrate to the periphery in the few hours after DNA synthesis. The late intrathymic expansion phase demonstrated here increases the daily thymic cell export by at least 30%. It could play a role in the adjustment of the T cell repertoire before emigration and in the regulation of the thymic cell output into the peripheral T cell pool.

Delayed spontaneous alternation in intact and cerebellectomized control and lurcher mutant mice: differential role of cerebellar cortex and deep cerebellar nuclei

Lurcher mutant (+/Lc) mice exhibit a massive loss of neurons in the cerebellar cortex and in the inferior olivary nucleus while deep cerebellar nuclei are essentially intact. To discriminate the respective participation of the cerebellar cortex and deep structures in learning and memory, the authors subjected 3- to 6-month-old +/Lc mice to a delayed spontaneous alternation task to test their working and long-term spatial memories. Results show that wild type (+/+) mice alternated above chance even after a 1-hr delay between the forced and choice trials, whereas in +/Lc mice, long-term memory was impaired. Cerebellectomized +/+ mice behave as +/Lc mice (working memory was preserved but long-term memory was not), whereas in the cerebellectomized +/Lc mice, both working and long-term memories were altered. These results are discussed in terms of relationships between the cerebellum and the hippocampus.

In vivo T cell response to viral superantigen. Selective migration rather than proliferation

Superantigens induce T cell activation and proliferation in vitro, and some also induce cell activation in vivo. MMTV(SW) is an infectious mouse mammary tumor virus (MMTV) encoding a superantigen with the same Vbeta specificity as MIs-1a (Mtv-7), which induces a strong local response in vivo. injection of MMTV(SW) into mouse footpads leads to accumulation of superantigen-reactive T cells (Vbeta6+CD4+) and B cells in the draining lymph nodes (LN). We investigated the kinetics of this cell accumulation by measuring cell activation (blastogenesis, CD25 and CD69 expression), cell migration (using syngenic FITC-labeled CD4+ cells and L-selectin detection), and cell proliferation (using in vivo labeling with bromodeoxyuridine). Specific T cells selectively migrated to the draining LN. Accumulating Vbeta6+CD4+ T cells were large CD69+ cells, but remained CD25 negative and showed down-regulated L-selectin expression. Their DNA synthesis rate, studied by pulse labeling and continuous administration of bromodeoxyuridine, was increased, but remained too low to explain the draining LN hyperplasia. These data show that the local T cell response to MMTV(SW) mainly consists of selective migration followed by local activation of reactive T cells, and that cell proliferation is only a minor component of the response. By contrast, the optimal dose of staphylococcal enterotoxin B that, nevertheless, leads to a lower reactive T cell accumulation in the draining LN induces a very high proliferation rate.

In vivo T cell response to viral superantigen. Selective migration rather than proliferation

Superantigens induce T cell activation and proliferation in vitro, and some also induce cell activation in vivo. MMTV(SW) is an infectious mouse mammary tumor virus (MMTV) encoding a superantigen with the same Vbeta specificity as MIs-1a (Mtv-7), which induces a strong local response in vivo. injection of MMTV(SW) into mouse footpads leads to accumulation of superantigen-reactive T cells (Vbeta6+CD4+) and B cells in the draining lymph nodes (LN). We investigated the kinetics of this cell accumulation by measuring cell activation (blastogenesis, CD25 and CD69 expression), cell migration (using syngenic FITC-labeled CD4+ cells and L-selectin detection), and cell proliferation (using in vivo labeling with bromodeoxyuridine). Specific T cells selectively migrated to the draining LN. Accumulating Vbeta6+CD4+ T cells were large CD69+ cells, but remained CD25 negative and showed down-regulated L-selectin expression. Their DNA synthesis rate, studied by pulse labeling and continuous administration of bromodeoxyuridine, was increased, but remained too low to explain the draining LN hyperplasia. These data show that the local T cell response to MMTV(SW) mainly consists of selective migration followed by local activation of reactive T cells, and that cell proliferation is only a minor component of the response. By contrast, the optimal dose of staphylococcal enterotoxin B that, nevertheless, leads to a lower reactive T cell accumulation in the draining LN induces a very high proliferation rate.

Thymic medulla epithelial cells acquire specific markers by post-mitotic maturation

The development of thymocyte subsets and of the thymic epithelium in SCID and RAG-2/-mice was monitored after normal bone-marrow-cell transfer. The kinetics of thymic reconstitution and their relationships with cell proliferation were investigated by using bromodeoxyuridine to detect DNA-synthesizing cells among lymphoid cells by 3-color flow cytometry, and in epithelial compartments by staining frozen sections. Thymocytes started to express CD8 and CD4 10 days after transfer, simultaneously with extensive proliferation. The first mature CD4+ single-positive cells were generated, from resting CD4+CD8+ cells after day 15. During this day 10-15 period, many epithelial cells positive for cortex-specific or panepithelial markers were labeled with BrdUrd after pulse-injection. Organized medullary epithelium also developed after day 15, that is, synchronously with the appearance of mature thymocytes, but medullary cells were never found BrdUrd+. These results suggest that, in these models, the reconstitution of the thymic epithelial network proceeds through expansion of preexisting cortical or undifferentiated cells and by later maturation (acquisition of specific markers) of medullary cells. This last process is dependent of the presence of mature thymocytes.

Keratoderma with scleroatrophy of the extremities or sclerotylosis (Huriez syndrome): a reappraisal

Keratoderma with scleroatrophy of the extremities, also referred to as Huriez syndrome, is a rare, autosomal dominant condition, first described in 42 of 132 members of two families from northern France. The term sclerotylosis was proposed because of the pseudosclerodermatous appearance of the hands and digits. The distinctive feature of this syndrome is the risk of the development of squamous cell carcinoma on affected skin. Since the initial description of this disease, three other families, and possibly a fourth, have been reported. In the present study, we reassessed the clinical, pathological and genetic data in 114 members of one of the two original families, of whom 27 were affected by this syndrome.

Differential roles of cerebellar cortex and deep cerebellar nuclei in the learning of the equilibrium behavior: studies in intact and cerebellectomized lurcher mutant mice

Three- to 6-month-old lurcher mutant mice (+/lc), which exhibit a massive loss of neurons in the cerebellar cortex and in the inferior olivary nucleus but whose deep cerebellar nuclei are essentially intact, were trained daily, for 9 days, to maintain their equilibrium upon a rota rod rotating at 20 or 30 revolutions per minute (rpm). Their scores were measured and their behavior upon the rotating rod quantified in comparison to those of matched control (+/+) mice. Lurcher mice were able to learn to maintain their equilibrium efficiently when rotated at 20 rpm but were not when rotated at 30 rpm. After cerebellectomy, the equilibrium capabilities of the animals were much altered, especially in +/lc. These results show that the deep cerebellar nuclei are sufficient for motor learning, provided the task is not too difficult (20 rpm), but that the cerebellar cortex is required when the task is more difficult (30 rpm). Therefore, it can be concluded that the adaptive motor capabilities of lurcher mice are less developed than those of control animals.

Cell expansion and growth arrest phases during the transition from precursor (CD4-8-) to immature (CD4+8+) thymocytes in normal and genetically modified mice

T cell early precursors belong to the CD3-CD4-CD8- triple negative (TN) thymocyte population that can be subdivided on the basis of CD44, CD25, and heat-stable Ag (HSA) expression. The kinetics and precursor product relationships of these subsets, as well as of the CD4/8low intermediates, were studied by using pulse labeling with bromodeoxyuridine (BrdUrd). The highest frequencies of DNA-synthesizing cells were found in CD44+CD25+ and CD44-CD25low or CD25- subsets. The major TN cell type (CD44-CD25high), as well as CD44+ CD25-HSAlow early precursors, contained a majority of resting cells. RAG-2-/- mice contained less cells in DNA synthesis than normal mice, and CD44-CD25-/low cells were absent. In female mice transgenic for the anti-HYTCR, CD44-CD25high cells were almost all cycling, but a high percentage of resting cells was found in CD44-CD25- cells. In days following the BrdUrd pulse, there was a reduction in the number of BrdUrd+ cells in most subsets, with the exception of the labeled CD44-CD25high cells that showed a bell-shaped curve. The kinetics and cell size evolution suggest that the majority of these cells do not give rise to CD4+CD8+ cells. In RAG-2-/- cells, the block at the CD44-CD25high stage involved all cells. In TCR transgenic (Tg) mice, no block was seen at the CD44-CD25high stage, suggesting that early expression of a complete TCR receptor precludes the normal selection step. However, another block in the differentiation process was observed at the CD44-CD25- step in TCR Tg mice, suggesting an additional selection point.

Cell expansion and growth arrest phases during the transition from precursor (CD4-8-) to immature (CD4+8+) thymocytes in normal and genetically modified mice

T cell early precursors belong to the CD3-CD4-CD8- triple negative (TN) thymocyte population that can be subdivided on the basis of CD44, CD25, and heat-stable Ag (HSA) expression. The kinetics and precursor product relationships of these subsets, as well as of the CD4/8low intermediates, were studied by using pulse labeling with bromodeoxyuridine (BrdUrd). The highest frequencies of DNA-synthesizing cells were found in CD44+CD25+ and CD44-CD25low or CD25- subsets. The major TN cell type (CD44-CD25high), as well as CD44+ CD25-HSAlow early precursors, contained a majority of resting cells. RAG-2-/- mice contained less cells in DNA synthesis than normal mice, and CD44-CD25-/low cells were absent. In female mice transgenic for the anti-HYTCR, CD44-CD25high cells were almost all cycling, but a high percentage of resting cells was found in CD44-CD25- cells. In days following the BrdUrd pulse, there was a reduction in the number of BrdUrd+ cells in most subsets, with the exception of the labeled CD44-CD25high cells that showed a bell-shaped curve. The kinetics and cell size evolution suggest that the majority of these cells do not give rise to CD4+CD8+ cells. In RAG-2-/- cells, the block at the CD44-CD25high stage involved all cells. In TCR transgenic (Tg) mice, no block was seen at the CD44-CD25high stage, suggesting that early expression of a complete TCR receptor precludes the normal selection step. However, another block in the differentiation process was observed at the CD44-CD25- step in TCR Tg mice, suggesting an additional selection point.

Stochastic coreceptor shut-off is restricted to the CD4 lineage maturation pathway

Kinetics of mature T cell generation in the thymus of normal or major histocompatibility complex (MHC) class I- or II-deficient mice were studied by the bromodeoxyuridine pulse labeling method. As previously described, the early activation and final maturation phases were found to be synchronous for the two T cell lineages, but CD4+8- cells were generated faster than CD4-8+ cells in MHC class I- and II-deficient mice, respectively. CD8 downregulation started on day 2 after cell proliferation even in the absence of MHC class II expression. CD8 downregulation thus appears to be stochastic at its beginning. By contrast, CD4 shut-off was found totally instructive, as the generation of CD4lo8+ cells with a high TCR density was not observed in class I-deficient mice. The analysis of the V beta 14 TCR frequencies in CD4/8 subsets in normal and MHC-deficient mice confirmed that CD4 and CD8 generation pathways are not symmetrical. These findings show that commitment towards the CD4+8- or CD4-8+ phenotype is controlled at the CD8lo step for the former and at the CD4+8+ double-positive stage for the latter.

Production, selection, and maturation of thymocytes with high surface density of TCR

The main steps in intrathymic T cell differentiation have been defined using bromodeoxyuridine as a postmitotic cell tracer. Thymocytes with a high surface expression of the TCR are generated in the first 24 h after DNA synthesis. The phenotype of these TCR(high) cells was studied during 10 days by using pairs of surface markers associated with BrdUrd. During the first 2 days, TCR(high) cells were of the CD4+CD8+HSA(high) phenotype, transiently expressed the early activation marker CD69, and contained a high percentage of cycling cells. This activation step preceded the transition from CD4+CD8+ to CD4+CD8- and then to CD4-CD8+ cells, followed by progressive HSA down regulation and increase in the expression of H-2K, Qa-2, and CD45RB. The phenotypic maturation was completed in 9 days. In Mls-1a mice, negative selection of V beta 6+ cells was observed at the earliest step of TCR(high) cell generation, and positive selection of V beta 8.2+ and V beta 14+ cells took place later and was correlated to the activation step. These data suggest that high TCR expression and cell activation are necessary for positive selection and subsequent T cell maturation.