Biomedical subjects

A Reis

Publications and source records attributed to A Reis.

At least 55 records · Page 3Linked to original sources

PubMed2002

Exclusion of the neuronal nicotinic acetylcholine receptor alpha7 subunit gene as a candidate for catatonic schizophrenia in a large family supporting the chromosome 15q13-22 locus.

The gene encoding the neuronal nicotinic acetylcholine receptor alpha7 subunit (CHRNA7) is located on chromosome 15q13.2. This region was suggested to be involved in the etiopathogenesis of: (a) schizophrenia combined with a neurophysiological deficit; (b) lithium-responsive bipolar disorder; and (c) familial catatonic schizophrenia (periodic catatonia). Therefore, members of a large family with periodic catatonia strongly supporting the chromosome 15q13-22 region were genotyped with polymorphic markers localized around the CHRNA7 locus. A recombination event distally of marker D15S144 leading to the exclusion of the CHRNA7 locus from this candidate region was detected in one branch of the pedigree. This result provides strong evidence that a gene located telomeric to CHRNA7 is causative for the pathogenesis of catatonic schizophrenia in this family.

Chromosomes, Human, Pair 15↗

PubMed2001

Monocyte function and plasma levels of interleukin-8 in acute ischemic stroke.

Activated monocytes may contribute to the pathogenesis of ischemic stroke. We tested the hypothesis that release products and procoagulant activity of monocytes are increased in acute ischemic stroke. In patients on days 1, 3 and 7 after ischemic stroke and in age- and sex-matched healthy control subjects, we assessed plasma levels of interleukin 8 (IL-8) and neopterin (enzyme linked immunosorbent assay, ELISA) and investigated superoxidanion release (ferricytochrome C reduction), procoagulant activity (one-stage clotting assay) and tissue factor (TF) gene transcription (reverse transcriptase polymerase chain reaction) by monocytes. As compared to control subjects (n=23), IL-8 levels were increased on day 1 after stroke (n=22; p=0.005) and remained elevated on days 3 and 7. Neopterin levels were elevated on days 3 and 7 (p<0.05, respectively) but not on day 1. Neopterin and IL-8 were not correlated with monocyte counts. Superoxid anion production by stimulated and unstimulated monocytes was not different between groups. TF mRNA could neither be detected in monocytes from patients investigated within 12 h after ischemia (n=12) nor in control subjects (n=10) and procoagulant activity of cells was similar in both groups. Our results indicate increased monocyte activation after ischemic stroke although not all activation parameters were elevated. We found no support for the hypothesis that circulating monocytes express TF and possess increased procoagulant activity. Elevated IL-8 may contribute to stroke pathophysiology by activating polymorphonuclear leukocyte (PMNL) activation early after ischemia.

Acute Disease↗

PubMed2001

Synovial hemangioma in Hoffa's fat pad (case report).

A 15-year-old girl presented with anterolateral knee pain for 6 months. There were tenderness and pain at the anterolateral triangulation of the knee joint. Magnetic resonance imaging revealed a tumor in the anterolateral corner of the knee joint. Arthroscopy did not show the tumor because it was located in fat pad. The tumor was found during fat pad shaving and was resected arthroscopically. Synovial hemangioma was demonstrated histologically. The patient is asymptomatic postoperatively.

Adipose Tissue↗

PubMed2001

Identification, by homozygosity mapping, of a novel locus for autosomal recessive congenital ichthyosis on chromosome 17p, and evidence for further genetic heterogeneity.

Autosomal recessive congenital ichthyosis (ARCI) comprises a group of severe disorders of keratinization, characterized by variable erythema and skin scaling. It is known for its high degree of genetic and clinical heterogeneity. Mutations in the gene for keratinocyte transglutaminase (TGM1) on chromosome 14q11 were shown in patients with ARCI, and a second locus was described, on chromosome 2q, in families from northern Africa. Three other loci for ARCI, on chromosomes 3p and 19p, were identified recently. We have embarked on a whole-genome scan for further loci for ARCI in four families from Germany, Turkey, and the United Arab Emirates. A novel ARCI locus was identified on chromosome 17p, between the markers at D17S938 and D17S1856, with a maximum LOD score of 3.38, at maximum recombination fraction 0.00, at D17S945, under heterogeneity. This locus is linked to the disease in the Turkish family and in the German family. Extensive genealogical studies revealed that the parents of the German patients with ARCI were eighth cousins. By homozygosity mapping, the localization of the gene could then be refined to the 8.4-cM interval between D17S938 and D17S1879. It could be shown, however, that ARCI in the two Arab families is linked neither to the new locus on chromosome 17p nor to one of the five loci known previously. Our findings give evidence of further genetic heterogeneity that is not linked to distinctive phenotypes.

Adolescent↗

PubMed2001

Mutations in the Nijmegen Breakage Syndrome gene (NBS1) in childhood acute lymphoblastic leukemia (ALL).

The Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive disorder associated with immune deficiency, chromosome fragility, and increased susceptibility to lymphoid malignancies. The aim of the present study was to elucidate the potential role of the gene mutated in NBS (NBS1) in the pathogenesis and disease progression of childhood acute lymphoblastic leukemia (ALL). Samples from 47 children with first relapse of ALL were analyzed for mutations in all 16 exons of the NBS1 gene, and in 7 of them (14.9%), four novel amino acid substitutions were identified. Mutations S93L, D95N, and I171V occur in the two known domains of nibrin that are probably involved in protein-protein interactions. Germ-line origin of the I171V mutation was confirmed in three patients, whereas the D95N exchange was present only in leukemic cells. The R215W mutation was observed in one ALL but also in a population-based study and probably represents a rare sequence variant. No additional mutations were found on the second allele in any of these seven patients. The observed NBS1 gene mutations in ALL patients points to its possible involvement in the pathogenesis of this disease.

Adolescent↗

PubMed2001

First known microdeletion within the Wolf-Hirschhorn syndrome critical region refines genotype-phenotype correlation.

Deletions within HSA band 4p16.3 cause Wolf-Hirschhorn syndrome (WHS), which comprises mental retardation and developmental defects. A WHS critical region (WHSCR) of approximately 165 kb has been defined on the basis of 2 atypical interstitial deletions; however, genotype-phenotype correlation remains controversial, due to the large size of deletion usually involving several megabases. We report on the first known patient with a small de novo interstitial deletion restricted to the WHSCR who presented with a partial WHS phenotype consisting only of low body weight for height, speech delay, and minor facial anomalies; shortness of stature, microcephaly, seizures and mental retardation were absent. The deletion was initially demonstrated by FISH analysis, and breakpoints were narrowed with a "mini-FISH" technique using 3-5 kb amplicons. A breakpoint-spanning PCR assay defined the distal breakpoint as disrupting the WHSC1 gene within intron 5, exactly after an AluJb repeat. The proximal breakpoint was not found to be associated with a repeated sequence or a known gene. The deletion encompasses 191.5 kb and includes WHSC2, but not LETM1. Thus, manifestations attributable to this deletion are reduced weight for height, minor facial anomalies, ADHD and some learning and fine motor deficiencies, while seizures may be associated with deletions of LETM1.

Abnormalities, Multiple↗

PubMed2001

Cloning of the mouse dysferlin gene and genomic characterization of the SJL-Dysf mutation.

The SJL mouse strain has been widely used as an animal model for experimental autoimmune encephalitis (EAE), inflammatory muscle disease and lymphomas and has also been used as a background strain for the generation of animal models for a variety of diseases including motor neurone disease, multiple sclerosis and atherosclerosis. Recently the SJL mouse was shown to have myopathy due to dysferlin deficiency, so that it can now be considered a natural animal model for limb-girdle muscular dystrophy type 2B (LGMD2B) and Miyoshi myopathy (MM). We have cloned the mouse dysferlin cDNA and analysis of the sequence shows that the mouse dysferlin gene is characterized by six C2 domain sequences and a C-terminal anchoring domain, with the human and the mouse dysferlin genes sharing > 90% sequence homology overall. Genomic analysis of the SJL mutation confirms that the 171 bp RNA deletion has arisen by exon skipping resulting from a splice site mutation. The identification of this mutation has implications for the various groups using this widely available mouse stock.

Amino Acid Sequence↗

PubMed2001

Assignment of PGL3 to chromosome 1 (q21-q23) in a family with autosomal dominant non-chromaffin paraganglioma.

We performed a whole genome scan in a family with maternally transmitted paraganglioma (PGL3). The family included five patients with histologically proven paraganglioma and one patient with imaging findings consistent with a paraganglioma. In addition, there were 33 clinically unaffected family members. Of these eight could be examined by magnetic resonance imaging. Our investigations indicate that PGL3 is located in 1q21-q23 for several reasons: 1) two-point linkage analysis yielded the highest LOD score of 2.25 at 1q21-q23 (marker D1S2675); 2) haplotype analysis was most consistent for 1q21-q23 markers; and 3) the locus was excluded from more than 97% of the genome using a total of 381 highly polymorphic markers.

Chromosomes, Human, Pair 1↗

PubMed2001

Fine mapping and single nucleotide polymorphism association results of candidate genes for asthma and related phenotypes.

Several genome-wide screens for asthma and related phenotypes have been published to date but data on fine-mapping are scarce. For higher resolution we performed a fine-mapping study with 2 cM average spacing in often discussed asthma candidate regions (2p, 5q, 6p, 7p, 9q, 11p, and 12q) to narrow down the regions of interest. All participants of a Caucasian family study (97 families with at least two affected sib pairs) were genotyped for 49 supplementary polymorphic dinucleotide markers. Our results indicate increased evidence for linkage on chromosome 6p, 9q, and 12q. These candidate regions were further analyzed with SNP polymorphisms in the endothelin 1 (EDN1), lymphotoxin alpha (LTA), and neuronal nitric oxide synthase (NOS1) genes. In addition, IL4 -590C>T and IL10 -592C>A, localized on chromosomes 5q and 1q, respectively, have been analyzed for SNP association. Of the six SNPs tested, four revealed weak association with the examined phenotypes. These are the IL10 -592C>A SNP in the interleukin 10 gene (p=0.036 for eosinophil cell counts), the 4124T>C SNP in EDN1 (p=0.044 for asthma), the 3391C>T SNP in NOS1 with eosinophil cell counts (p=0.0086), and the 5266C>T polymorphism, also in the NOS1 gene, for high IgE levels (p=0.022). In summary, fine mapping data enable us to confine asthma candidate regions, while variants of EDN1 and NOS1, or nearby genes, may play an important role in this context.

Asthma↗

PubMed2001

Formal schooling influences two- but not three-dimensional naming skills.

The modulatory influence of literacy on the cognitive system of the human brain has been indicated in behavioral, neuroanatomic, and functional neuroimaging studies. In this study we explored the functional consequences of formal education and the acquisition of an alphabetic written language on two- and three-dimensional visual naming. The results show that illiterate subjects perform significantly worse on immediate naming of two-dimensional representations of common everyday objects compared to literate subjects, both in terms of accuracy and reaction times. In contrast, there was no significant difference when the subjects named the corresponding real objects. The results suggest that formal education and learning to read and to write modulate the cognitive process involved in processing two- but not three-dimensional representations of common everyday objects. Both the results of the reaction time and the error pattern analyses can be interpreted as indicating that the major influence of literacy affects the visual system or the interaction between the visual and the language systems. We suggest that the visual system in a wide sense and/or the interface between the visual and the language system are differently formatted in literate and illiterate subjects. In other words, we hypothesize that the pattern of interactions in the functional-anatomical networks subserving visual naming, that is, the interactions within and between the visual and language processing networks, differ in literate and illiterate subjects.

Aged↗

PubMed2001

Characterization of a mutation in the lens-specific MP70 encoding gene of the mouse leading to a dominant cataract.

During an ethylnitrosourea mutagenesis screen, Aey5, a new mouse mutation exhibiting an autosomal dominant congenital cataract was isolated. The cataractous phenotype is visible at the eye opening and progresses to a nuclear and zonular cataract at 2 months of age with no difference in onset or severity between heterozygous and homozygous mutants. Histological analysis revealed that fiber cell differentiation continues at the lens bow region, but the cell nuclei do not degrade normally and remain in the deeper cortex. Further, the lens nucleus has clefts of various sizes while the remainder of the eye was morphologically normal. The mutation was mapped to chromosome 3 between the markers D3Mit101 and D3Mit77 near the connexin encoding genes Gja5 and Gja8. Sequence analysis revealed no differences in the Gja5 gene, but identified a T-->C mutation at position 191 in the Gja8 gene, which was confirmed by an additional Mva 12691 restriction site in the genomic DNA of homozygous mutants. This mutation results in Val-->Ala substitution at codon 64 of connexin50 (Cx50) also known as lens membrane protein 70 (MP70). Aey5 represents the second dominant mouse cataract mutant affecting Cx50, a membrane protein preferentially expressed in the lens. Since both mutations affect similar regions in the first extracellular domain this region appears to be critically important for its function in lens transparency.

Animals↗

PubMed2001

Identification and localization of a new human myotubularin-related protein gene, mtmr8, on 8p22-p23.

Myotubularin and myotubularin-related proteins are dual-specificity phosphatases. Several myotubularin-related proteins have been identified in humans and mice. The members of the myotubularin protein family are highly conserved, from humans to yeast. Mutations in the human myotubularin gene (MTM1) lead to X-linked myotubular myopathy. Here we isolate and localize a novel putative myotubularin-related protein gene (MTMR8) on chromosome 8p22--p23,between the markers D8S550 and D8S265, by exon-trapping experiments and RT-PCR. Genomic sequencing revealed that the gene consists of 10 exons and spans approximately 43 kb. The corresponding cDNA is 7081 bp. The open reading frame predicts a protein of 549 amino acids and a calculated molecular mass of 63 kDa. Like myotubularin-related protein-5, MTMR8 has no dual-specificity phosphatase domain. It contains a double-helical motif similar to the SET interaction domain, which is thought to have a role in the control of cell proliferation.

Amino Acid Sequence↗

PubMed2001

Towards the genetic basis of periodic catatonia: pedigree sample for genome scan I and II.

In a genome-wide linkage study, we mapped two major susceptibility loci for periodic catatonia, a phenotype with qualitative disturbances of the psychomotor sphere and a morbidity risk of 26.9% in first-degree relatives of index cases, to chromosome 15q15, and to chromosome 22q13 using nonparametric as well as parametric (autosomal dominant model) analyses. The study included 12 multiplex pedigrees with 135 individuals, among them 57 affected persons. A second genome scan is in progress investigating four families with 21 affected individuals, aiming to confirm linkage results. Age at onset patterns as well as the clinical outcome were similar among affected individuals in both sets of families. Within the pedigrees we observed no physical diseases segregating with periodic catatonia. Under the assumption of genetic homogeneity, the statistical power to detect LOD scores > or = 2.0 was 98.5% in the first set of families, and 57.9% in the second set. Thus, the panel of multiplex pedigrees segregating periodic catatonia seems to represent a homogenous clinical sample, and possesses sufficient statistical power to delineate and confirm linkage to major genetic loci for periodic catatonia.

Adult↗

PubMed2001

RAD, a new immunosuppressive macrolide in murine corneal transplantation.

BACKGROUND: RAD is a novel macrolide immunosuppressant with effects on growth factor signalling. We investigated the potency of RAD in inhibiting allograft rejection in the rat model of orthotopic allogeneic penetrating keratoplasty. METHODS: Fifty-four allogeneic orthotopic penetrating keratoplasties were performed using Fisher rats as donors and Lewis rats as recipients. The animals were divided into five groups: syngeneic control, allogeneic control, RAD 1.5 mg/kg bw per day, RAD 2.5 mg/kg bw per day, cyclosporin A (CSA) 10 mg/kg bw per day. Medication started on the day of operation and continued daily for the duration of 18 days. Each animal was examined by slit-lamp microscopy every 3rd day. For immunohistological evaluation rats were killed on day 14. Immunohistology was performed using monoclonal mouse anti-rat antibodies against CD4, CD8, CD25, CD45 and CD54. RESULTS: The average transplant survival time in the allogeneic combination was 12.3 days (+/- 0.3). Therapy with RAD 1.5 mg/kg and 2.5 mg/kg led to a statistically significant prolongation of transplant survival to 32.3 days (+/- 11.3, P<0.05) and 37.7 days (+/- 12.5), respectively. This efficacy was similar to that of CSA 10 mg/kg (39.7 +/- 12.5 days). There was a statistically significant reduction in the number of CD4+, CD8+ as well as CD45+ cells in both the RAD- and the CSA-treated animals compared with the allogeneic control. CONCLUSIONS: The results show that oral immunosuppression with RAD significantly prolongs corneal allograft survival. Further investigation of RAD in preclinical and clinical high-risk keratoplasty is warranted.

Administration, Oral↗

PubMed2001

Systemic mycophenolate mofetil in comparison with systemic cyclosporin A in high-risk keratoplasty patients: 3 years' results of a randomized prospective clinical trial.

BACKGROUND: With the use of systemic cyclosporin A (CsA), graft prognosis after high-risk penetrating keratoplasty has improved considerably. However, the application of CsA is limited owing to a variety of severe side effects. In this prospectively randomized study mycophenolate mofetil (MMF), a safe and efficient immunosuppressive medication after renal transplantation, was compared with CsA after high-risk penetrating keratoplasty. METHODS: Twenty-nine high-risk keratoplasty patients were treated with MMF 2x 1 g daily; another 27 patients received CsA, aiming at blood trough levels of 120-150 ng/ml. Systemic immunosuppression was scheduled for 6 months. In both groups oral corticosteroids (fluocortolone 1 mg/kg) were administered for 3 weeks postoperatively. RESULTS: During the first year after operation, no graft failure was recorded. Two years postoperatively 92%/82% and 3 years postoperatively 74%/69% of grafts were clear in the MMF and CsA group, respectively (Kaplan Meier P=0.33, logrank test). In total, two graft failures were recorded in the MMF group and four in the CsA group. Three years postoperatively 53% of the grafts were rejection-free in the MMF group and 73% in the CsA group (Kaplan Meier P=0.46, log-rank test). Eight endothelial immune reactions were observed in the MMF group (three under systemic immunosuppression/five thereafter; six mild/two severe) and five in the CsA group (three under systemic immunosuppression/two thereafter; three mild/two severe). Side effects occurred in six patients under MMF and 11 under CsA. CONCLUSIONS: Concerning efficacy, no statistically significant difference between systemic MMF and systemic CsA administered for 6 months after high-risk penetrating keratoplasty could be shown. Systemic MMF was proven to be at least as safe as CsA. The main mechanism in improving graft survival is a shift from severe to milder endothelial immune reactions, as already demonstrated for CsA. Thus, MMF may become an alternative to CsA for immunosuppression after penetrating high-risk keratoplasty. About 2 years postoperatively, pharmacologically induced relative immunological tolerance slowly decreases. Therefore, long-term administration of systemic MMF should be evaluated in further studies.

Adolescent↗

PubMed2001

Epigenetic targeting in the mouse zygote marks DNA for later methylation: a mechanism for maternal effects in development.

The transgenic sequences in the mouse line TKZ751 are demethylated on a DBA/2 inbred strain background but become highly methylated at postimplantation stages in offspring of a cross with a BALB/c female. In the reciprocal cross the transgene remains demethylated suggesting that imprinted BALB/c methylation modifiers or egg cytoplasmic factors are responsible for this striking maternal effect on de novo methylation. Reciprocal pronuclear transplantation experiments were carried out to distinguish between these mechanisms. The results indicate that a maternally-derived oocyte cytoplasmic factor from BALB/c marks the TKZ751 sequences at fertilization; this mark and postzygotic BALB/c modifiers are both required for de novo methylation of the target sequences at postimplantation stages. Using genetic linkage analyses we mapped the maternal effect to a locus on chromosome 17. Moreover, seven postzygotic modifier loci were identified that increase the postimplantation level of methylation. Analysis of interactions between the maternal and the postzygotic loci shows that both are needed for de novo methylation in the offspring. The combined experiments thus reveal a novel epigenetic marking process at fertilization which targets DNA for later methylation in the foetus. The most significant consequence is that the genotype of the mother can influence the epigenotype of the offspring by this marking process. A number of parental and imprinting effects may be explained by this epigenetic marking.

Alleles↗

PubMed2001

Comparative association analysis reveals that corneodesmosin is more closely associated with psoriasis than HLA-Cw0602-B5701 in German families.

HLA antigens are associated with psoriasis vulgaris across populations with different ethnic background. We have previously shown that in Caucasians this association is primarily based on the class I alleles of the extended HLA haplotype 57.1 (EH57.1/I), HLA-Cw6-HLA-B57. However, it remained unclear whether HLA-Cw6 itself or a closely linked locus predisposes to the disease. An interesting candidate for this presumed locus is corneodesmosin, which is exclusively synthesized in keratinocytes. The corneodesmosin gene locus (CDSN) is only 160 kb telomeric to HLA-C and tightly associated with psoriasis. In order to find out whether EH57.1/I or a corneodesmosin variant are the susceptibility determinants on 6p, HLA class I alleles and single-nucleotide polymorphisms (SNPs) of corneodesmosin were investigated at the sequence level and analyzed by comparative association tests. Transmission disequilibrium tests (TDT) were performed in 52 nuclear families, of which 36 were fully informative for a joint comparison of HLA and CDSN with regard to association to psoriasis. The extended TDT according to Wilson was employed to test for locus interaction. Using the HLA haplotype EH57.1/I and the CDSN haplotype formed by three intragenic variant sites at nt=619 (T), 1236 (T), and 1243 (C), we obtained the best resolution of parental transmission to index cases in the trio families. On direct comparison of the contributions of the HLA and the CDSN haplotypes, there was a markedly stronger association of the corneodesmosin TTC haplotype, which is not apparent in single locus analysis. We show furthermore that there is no higher order interaction between psoriasis, HLA, and CDSN. This lack of three-locus interaction is suggestive of two independent genetic contributions to psoriasis within the major histocompatibility complex (MHC).

Alleles↗

PubMed2001

Mutations in CAV3 cause mechanical hyperirritability of skeletal muscle in rippling muscle disease.

Hereditary rippling muscle disease (RMD) is an autosomal dominant human disorder characterized by mechanically triggered contractions of skeletal muscle. Genome-wide linkage analysis has identified an RMD locus on chromosome 3p25. We found missense mutations in positional candidate CAV3 (encoding caveolin 3; ref. 5) in all five families analyzed. Mutations in CAV3 have also been described in limb-girdle muscular dystrophy type 1C (LGMD1C; refs. 6,7), demonstrating the allelism of dystrophic and non-dystrophic muscle diseases.

Caveolin 3↗