The architecture of the tau haplotype block in different ethnicities

We have assessed the pattern of the extended haplotype block over the tau gene which covers a region of approximately 2 Mb in different ethnicities. This analysis shows that the pattern of linkage disequilibrium over the tau region is shared by different ethnic groups indicating that haplotype structure in human is ancient. We discuss this observation in terms of the establishment of the haplotype structure and the possible impact of the tau haplotype on neurodegeneration in humans.

Problems and Solutions in the Genetic Analysis of Late-Onset Alzheimer’s Disease

The identification of the apolipoprotein E gene as a risk factor for late-onset Alzheimer's disease was a spectacularly successful application of genetic analysis to a complex trait, and it led to the hope and expectation that other risk loci for the disease would soon be forthcoming. Twelve years later, despite a huge amount of work, no other loci have been identified. In this article, we discuss the complexity of the problem and the pitfalls in the analytical methods that have been used and how we are approaching this problem.

The tau H2 haplotype is almost exclusively Caucasian in origin

We have assessed the distribution of the tau H1/H2 haplotype in the publicly available reference series of samples with representatives of most racial groups. This analysis shows that the H2 haplotype is probably exclusively Caucasian in origin and its marginal occurrence in other racial groups is likely to reflect admixture. We discuss this observation in terms of the origin of the H2 haplotype and the epidemiology of the tauopathies.

Alpha-T-catenin is expressed in human brain and interacts with the Wnt signaling pathway but is not responsible for linkage to chromosome 10 in Alzheimer's disease

The gene encoding alpha-T-catenin, CTNNA3, is positioned within a region on chromosome 10, showing strong evidence of linkage to Alzheimer's disease (AD), and is therefore a good positional candidate gene for this disorder. We have demonstrated that alpha-T-catenin is expressed in human brain, and like other alpha-catenins, it inhibits Wnt signaling and is therefore also a functional candidate. We initially genotyped two single-nucleotide polymorphisms (SNPs) in the gene, in four independent samples comprising over 1200 cases and controls but failed to detect an association with either SNP. Similarly, we found no evidence for association between CTNNA3 and AD in a sample of subjects showing linkage to chromosome 10, nor were these SNPs associated with Abeta deposition in brain. To comprehensively screen the gene, we genotyped 30 additional SNPs in a subset of the cases and controls (n > 700). None of these SNPs was associated with disease. Although an excellent candidate, we conclude that CTNNA3 is unlikely to account for the AD susceptibility locus on chromosome 10.

More 'cries from the joints': assessment of the musculoskeletal system is poorly documented in routine paediatric clerking

OBJECTIVES

The aim of this study was to describe the assessment of the musculoskeletal (MSK) system in comparison with other systems in routine paediatric medical clerking. Furthermore, to survey trainee paediatricians (SPRs, specialist registrars) about their self-rated confidence in assessing the MSK system.

METHODS

Case notes of consecutive general paediatric medical patients admitted to three UK hospitals over a 4-week period were assessed using a standard pro forma. All patients had been assessed by a consultant paediatrician during their admission. A postal questionnaire was sent to all SPRs in training in each of the hospitals, regarding their confidence in assessing the MSK system compared with other systems and their exposure to MSK teaching.

RESULTS

Case notes of 257 patients [117 females, median age 3 yr (range 1-18 yr)] were reviewed. The most common reason for admission was acute infection, although the spectrum of other recorded diagnoses varied between hospitals. Thirteen children (5%) had an acute problem (e.g. infection) against a background of chronic disease. The case note documentation showed that cardiovascular (CVS), respiratory (RS) and gastrointestinal (GI) systems were assessed in the vast majority (>90%) of patients, irrespective of the underlying diagnosis. However, other systems were less well recorded; the trend being the same in each hospital and in descending order, the neurological system (38%), skin (32%), eyes (10%) and musculoskeletal system (4%). Only 2.7% (7/257) patients were documented to have been asked about MSK symptoms, and only 1.6% (4/257) had any documentation of joint examination--in all cases this was limited (e.g. range of movement of the knee only), and no patients had documentation of gait being examined, even in those children presenting with 'limp'. The response rate to the postal questionnaire was 60% (67/112). The self-rated confidence in MSK assessment was markedly low in comparison with other systems, even though 61/67 recalled some teaching of the MSK system as an undergraduate (61/67) or postgraduate (50/67). Of note none could recall teaching as an undergraduate in paediatric MSK assessment and where there had been postgraduate rheumatology MSK teaching this had been delivered by paediatric rheumatologists in many cases (34/50), reflecting the centres participating in the study.

CONCLUSIONS

In routine general paediatric medical in-patient clerking and throughout the admission, MSK assessment was rarely documented, and even where present was limited. This contrasts markedly with other systems which were examined in most children irrespective of the presenting complaint. Self-rated confidence in MSK assessment is low amongst SPRs compared with other systems, despite most recalling some teaching. This discrepancy between teaching and clinical practice needs to be addressed in undergraduate and postgraduate training.

The law of mass action applied to neurodegenerative disease: a hypothesis concerning the etiology and pathogenesis of complex diseases

Loci underlying autosomal dominant forms of most neurodegenerative disease have been identified: prion mutations cause Gerstmann Straussler syndrome and hereditary Creuzfeldt-Jakob disease, tau mutations cause autosomal dominant frontal temporal dementia, and alpha-synuclein mutations cause autosomal dominant Parkinson's disease. In all these cases, the pathogenic mutation is in the protein that is deposited in the diseased tissue and in these cases the whole protein is deposited. In Alzheimer's disease, mutations in APP or presenilin 1 or 2 cause autosomal dominant disease and these are the substrate and proteases, respectively, which are responsible for the production of the deposited peptide, Abeta. Thus, in all cases, the mutations lead to the disease by a mechanism that involves the deposition process. We briefly review this remarkably predictable biology, but also point out that it seems sporadic forms of all these diseases are predisposed to by genetic variability at the same loci, strongly suggesting that the quantity of the normal protein produced influences risk for the sporadic forms of the disease. The evidence for this assertion is strongest in Parkinson's disease (PD), where genetic variability in alpha-synuclein expression affects risk of developing disease, although the oldest evidence for the notion that increased expression of normal sequence protein can lead to disease comes from the observation of Alzheimer's disease in trisomy 21 cases. From these observations, we make predictions concerning the etiology and pathogenesis of neurodegenerative diseases in general.

Serum MMP-1 and TIMP-1 levels are increased in patients with psoriatic arthritis and their siblings

OBJECTIVE

To determine matrix metalloproteinase-1 (MMP-1) and tissue-inhibitor metalloproteinase-1 (TIMP-1) serum levels in patients with psoriatic arthritis (PsA) and to compare this with their siblings and local blood donor controls. PsA is an interesting condition in which to study metalloproteinases because there are variations in the level of destructiveness, including a significant proportion of cases without destructive change. This is unlike rheumatoid arthritis (RA) which is more uniformly destructive and where MMP-1/TIMP-1 levels are known to be elevated.

METHODS

MMP-1 and TIMP-1 serum levels were determined by enzyme-linked immunosorbent assay (ELISA) in (a) index cases with PsA (subtype: RA n = 43, distal interphalangeal disease n = 2, oligoarticular n = 15, spondyloarthropathy n = 9, enthesitis n = 1), (b) siblings with PsA, (c) siblings with psoriasis (Ps), (d) unaffected siblings and (e) local controls. Patients with Ps were divided according to the onset of disease: type I disease, onset before age 40 yr and type II, onset after age 40 yr.

RESULTS

MMP-1 and TIMP-1 levels were significantly increased in both the index cases and the group including all siblings compared with the controls (P < 0.0001). There was no statistical difference in MMP-1 or TIMP-1 levels between index cases and their siblings. There was no difference in serum MMP-1 level between the different subtypes (Moll and Wright) of PsA, but there was an increased level of serum TIMP-1 in patients with rheumatoid pattern (P = 0.05). In the index cases there were increased levels of TIMP-1 in type II onset psoriasis (P = 0.03) but no difference in MMP-1 levels.

CONCLUSION

MMP-1 and TIMP-1 serum levels are elevated in PsA. This is greatest in RA pattern PsA. These levels were also elevated in unaffected siblings suggesting that genetic factors may be important. TIMP-1 levels were elevated in psoriasis alone, more so in late onset psoriasis, suggesting that the pathological processes of early and late onset psoriasis may be different.

Non-human primates: a model for tuberculosis research

A variety of animals have been used for tuberculosis research, and each animal model has its strengths and weaknesses. We sought to develop a non-human primate model of tuberculosis to model aspects of human tuberculosis that are difficult to model in other animals, including the pathology in the lungs, various progression to disease, and immunologic correlates of infection or disease that are likely to be similar in humans. To date, we have infected 17 cynomolgus macaques (Macaca fasicularis) with a low dose (15-25CFU) of Mycobacterium tuberculosis strain Erdman. The monkeys were grouped into three categories on the basis of disease progression: rapid progression (advanced disease by 3 months post-infection), active/chronic infection (signs of disease but a slower progression), and latent infection (no signs of clinical disease). Animals were followed clinically post-infection, including blood work, physical examinations, serial bronchoalveolar lavage (BAL) and gastric aspirates for M. tuberculosis culture, chest radiographs, and tuberculin reactivity. Immunologic assays on cells from blood, BAL fluid, and tissue, have been performed, including proliferation, flow cytometry, ELIspot assays, cytotoxic T lymphocyte (CTL) assays, and ELISAs. The spectrum of disease observed in these monkeys is similar to humans, and this model may be very useful for studying pathogenesis and immunology of tuberculosis, as well as testing vaccines, diagnostic reagents, and drugs prior to use in human populations.

Sequence variation in the CHAT locus shows no association with late-onset Alzheimer's disease

There is substantial evidence for a susceptibility gene for late-onset Alzheimer's disease (AD) on chromosome 10. One of the characteristic features of AD is the degeneration and dysfunction of the cholinergic system. The genes encoding choline acetyltransferase (ChAT) and its vesicular transporter (VAChT), CHAT and SLC18A3 respectively, map to the linked region of chromosome 10 and are therefore both positional and obvious functional candidate genes for late-onset AD. We have screened both genes for sequence variants and investigated each for association with late-onset AD in up to 500 late-onset AD cases and 500 control DNAs collected in the UK. We detected a total of 17 sequence variants. Of these, 14 were in CHAT, comprising three non-synonymous variants (D7N in the S exon, A120T in exon 5 and L243F in exon 8), one synonymous change (H547H), nine single-nucleotide polymorphisms in intronic, untranslated or promoter regions, and a variable number of tandem repeats in intron 7. Three non-coding SNPs were detected in SLC18A3. None demonstrated any reproducible association with late-onset AD in our samples. Levels of linkage disequilibrium were generally low across the CHAT locus but two of the coding variants, D7N and A120T, proved to be in complete linkage disequilibrium.

Full genome screen for Alzheimer disease: stage II analysis

We performed a two-stage genome screen to search for novel risk factors for late-onset Alzheimer disease (AD). The first stage involved genotyping 292 affected sibling pairs using 237 markers spaced at approximately 20 cM intervals throughout the genome. In the second stage, we genotyped 451 affected sibling pairs (ASPs) with an additional 91 markers, in the 16 regions where the multipoint LOD score was greater than 1 in stage I. Ten regions maintained LOD scores in excess of 1 in stage II, on chromosomes 1 (peak B), 5, 6, 9 (peaks A and B), 10, 12, 19, 21, and X. Our strongest evidence for linkage was on chromosome 10, where we obtained a peak multipoint LOD score (MLS) of 3.9. The linked region on chromosome 10 spans approximately 44 cM from D10S1426 (59 cM) to D10S2327 (103 cM). To narrow this region, we tested for linkage disequilibrium with several of the stage II microsatellite markers. Of the seven markers we tested in family-based and case control samples, the only nominally positive association we found was with the 167 bp allele of marker D10S1217 (chi-square=7.11, P=0.045, df=1).

Is breast cancer in young Latinas a different disease?

BACKGROUND

Breast cancer appears to be more aggressive in young women (< or =35 years). Race/ethnicity may further influence prognosis. The purpose of this review is to determine whether breast cancer in young Latinas differs from that in other women.

METHODS

Our institutional (1977-2000) and state (1988-2000) tumor registries were reviewed and breast cancer cases analyzed. Data are expressed as mean +/- SEM.

RESULTS

At our institution, 56 (7%) of 748 breast cancer patients were < or =35 years old; 32 (57%) were Latina. Compared with non-Latinas, Latinas presented at a younger age (P <0.05) and had more stage III/IV disease (38% versus 29%; P >0.05) and bilaterality (22% versus 8%; P >0.05), and worse 5-year survival (63% versus 83%; P >0.05). Statewide data were consistent with our institutional data.

CONCLUSIONS

Latinas comprise a disproportionate share of our young breast cancer population, and may suffer more aggressive disease than other young women. Young Latinas may benefit from more vigilant screening and should be considered for novel therapeutic protocols.

Substantial linkage disequilibrium across the insulin-degrading enzyme locus but no association with late-onset Alzheimer's disease

Insulin-degrading enzyme (IDE; insulysin; EC 3.4.24.56) is a 110-kDa neutral metallopeptidase that can degrade a number of peptides including beta-amyloid. The gene encoding IDE is located on chromosome 10 close to a region of linkage for late-onset Alzheimer's disease (LOAD) and thus is a functional and positional candidate for this disorder. We analysed all of the coding exons, untranslated regions and 1000 bp of 5'-flanking sequence of IDE by using denaturing high-performance liquid chromatography and sequencing. We detected eight single nucleotide polymorphisms (SNPs), three in the 5' flanking sequence and five in the coding sequence, of which three were found at lower than 5% frequency. None of them changed the amino acid sequence. We genotyped the five SNPs with allele frequencies of more than 5% in 133 Caucasian LOAD cases and 135 controls collected in the UK and 95 cases and 117 controls collected at the Mayo Clinic, Rochester, USA. Two of the SNPs were analysed in a further independent case-control sample (Washington University, St. Louis: 86 cases, 94 controls). No significant association was found with any individual SNP in any of the samples or with any haplotypes. Analysis of the marker D10S583, which maps 36 kb upstream of IDE, also failed to show association in 134 cases and 111 matched controls from the UK ( P=0.63). Strong linkage disequilibrium was detected between the five SNPs that spanned the whole of the 120-kb genomic region of IDE and one major and a number of minor haplotypes were detected in the populations studied. We conclude that IDE does not make a substantial contribution to the aetiology of LOAD and therefore cannot account for the linkage between LOAD and 10q.

Effects of niacin-bound chromium and grape seed proanthocyanidin extract on the lipid profile of hypercholesterolemic subjects: a pilot study

Hypercholesterolemia, a significant cardiovascular risk factor, is prevalent in the American population. Many drugs lower circulating cholesterol levels, but they are not infrequently associated with severe side effects. Accordingly, natural means to lower cholesterol levels safely would be welcomed. We examined 40 hypercholesterolemic subjects (total cholesterol 210-300 mg/dL) in a randomized, double-blind, placebo-controlled study. The four groups of ten subjects received either placebo bid, chromium polynicotinate (Cr) 200 microg bid, grape seed extract (GSE) 100 mg bid, or a combination of Cr and GSE at the same dosage bid. Over two months, the average percent change +/- SEM in the total cholesterol from baseline among groups was: placebo -3.5% +/- 4, GSE -2.5% +/- 2, Cr -10% +/- 5, and combination -16.5% +/- 3. The decrease in the last group was significantly different from placebo (p < 0.01). The major decrease in cholesterol concentration was in the LDL levels: placebo -3.0% +/- 4, GSE -1.0% +/- 2.0, Cr -14% +/- 4.0, and the combination -20% +/- 6.0. Again, the combination of Cr and GSE significantly decreased LDL when compared to placebo (p<0.01). HDL levels essentially did not change among the groups. Also, there was no significant difference in the triglyceride concentrations among the groups; and no statistically significant differences were seen in the levels of autoantibodies to oxidized LDL (Ox-LDL). However, the trend was for the two groups receiving GSE to have greater decreases in the latter parameter, i.e., -30.7% and -44.0% in the GSE and combined groups in contrast to -17.3% and -10.4% in the placebo and chromium groups. We determined the number of subjects in each group who decreased autoantibodies to oxidized LDL greater than 50% over eight weeks and found these ratios among groups: placebo = 2/9, Cr = 1/10, GSE = 6/10, and combined = 3/8. Thus, 50% of subjects (9/18) receiving GSE had a greater than 50% decrease in autoantibodies compared to 16% (3/19) in the two groups not receiving GSE. No significant changes occurred in the levels of circulating homocysteine and blood pressure among the four groups. We conclude that a combination of Cr and GSE can decrease total cholesterol and LDL levels significantly. Furthermore, there was a trend to decrease the circulating autoantibodies to oxidized LDL in the two groups receiving GSE.

Genetic markers of male infertility: Y chromosome microdeletions and cystic fibrosis transmembrane conductance gene mutations

Today, approximately 15% of couples have reduced fertility. In most cases the reason is male infertility, usually of genetic origin. Thus, in the context of research in genes involved in reproduction and sex determination, genetic defects in gametogenesis are being extensively studied. The most frequent pathogenic causes of male infertility are Y chromosomal microdeletions and obstructive azoospermia due to congenital absence of the vas deferens (CAVD) in the presence of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. We have investigated the most common CFTR gene alterations in Croatian men with CAVD, using Roche research prototype assays. Results revealed that the 5T variant was present in 27% of the subjects. The F508 deletion was found in 21% of the subjects. It was the most frequent mutation, although its incidence was much lower than among patients with cystic fibrosis. The prevalence of microdeletions in the azoospermia factor region (AZF) of the Y chromosome in Croatia was 4.5%. This is the first report of Y microdeletions in the Croatian population. Genetic counseling of all couples with the diagnosis of male infertility is recommended before intrauterine insemination, in vitro fertilization, and intracytoplasmic sperm injection, and should also include AZF and CFTR genotyping. Couples requesting assisted reproductive treatment should be offered molecular analysis of the CFTR gene, if male infertility due to obstructive azoospermia is the underlying cause. Also, men with severe oligozoospermia or non-obstructive azoospermia seeking assisted reproductive treatment should be screened for deletions in the Y chromosome.

Liposomal daunorubicin in the treatment of relapsed or refractory non-Hodgkin's lymphoma

PURPOSE

To assess the efficacy and toxicity of liposomal daunorubicin administered as a two-hour intravenous infusion to patients with relapsed or refractory non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Eligible patients had relapsed or refractory NHL with measurable or evaluable disease, and low grade, select intermediate grade, or mantle cell pathologic types. Prior exposure to an anthracycline or anthracenedione was allowed. Liposomal daunorubicin at a dose of 100 mg/m2 was given intravenously over a minimum of 120 minutes every 3 weeks. as a single agent.

RESULTS

Thirty-three patients were accrued: twenty-three (70%) had low-grade histologies; six (18%) had intermediate-grade histologies (follicular large-cell and diffuse small cleaved); and four (12%) patients had mantle-cell lymphoma. Eighteen (55%) had received two or more prior regimens; fourteen (42%) received a prior anthracycline. A median of six cycles of liposomal daunorubicin were administered (range 1-15). Of 31 patients evaluable for response, 2 complete and 10 partial remissions were documented for a major response rate of 39% (95% confidence interval (CI): 22%-58%). The median duration of response was 19.5 months (range 4.3-41.1+). Six responders (50%) had received a prior anthracycline; one responder had mantle-cell histology. The major toxicities were grade 3 or 4 neutropenia in 26 patients (79%), mild to moderate nausea in 22 (67%), and fatigue in 16 (48%).

CONCLUSIONS

Liposomal daunorubicin at 100 mg/m2 every three weeks has activity in patients with relapsed or refractory NHL, including patients with prior exposure to an anthracycline. Further studies of liposomal daunorubicin in combination with other agents are warranted.