Cascade screening for familial hypercholesterolaemia: implications of a pilot study for national screening programmes.

OBJECTIVES: To determine what proportion of cases of heterozygous familial hypercholesterolaemia would be identified by cascade screening conducted by a specialist hospital clinic, and by how much this would increase the prevalence of diagnosed cases. SETTING: Hospital clinic serving a population of 605,900 in Oxfordshire, UK. METHODS: A specialist nurse obtained details of living first-degree relatives from 227 adult patients with heterozygous familial hypercholesterolaemia currently or previously attending Oxford lipid clinic after excluding 79 adults without relatives living in Oxfordshire and 48 children. Index cases were asked to invite relatives resident in Oxfordshire for testing. RESULTS: A total of 227 index cases had 1075 first-degree relatives, including 442 adults and 117 children aged < 18 years resident in Oxfordshire. We excluded 171 previously screened adults and 46 for other reasons. Among 225 eligible adult relatives, 28 responders (12%) planned to consult their general practitioner and 52 (23%) attended the clinic for testing. Parents of 113 children (97%) wanted them tested. The positive diagnostic rate was 29% (15/52) in adults and 32% (36/113) in children. Screening increased prevalence by 14.4%, from 0.58/1000 (95% confidence intervals [CI] 0.52-0.65) to 0.67/1000 (95% CI 0.60-0.73), representing 33.5% of predicted cases. CONCLUSIONS: Cascade screening conducted by a specialist hospital clinic within its population catchment area did not substantially increase the prevalence of diagnosed familial hypercholesterolaemia. To maximize response rates, clinic staff need to approach relatives directly. Validated age, sex and country-specific diagnostic criteria should be defined, possibly with access to DNA-based tests, to help resolve diagnostic uncertainty.

Cholesterol depletion with physiological concentrations of a statin decreases the formation of the Alzheimer amyloid Abeta peptide.

Epidemiological studies have demonstrated that hypercholsterolemia is a significant risk factor for Alzheimer's disease (AD). The mechanism by which increased cholesterol may contribute to AD is unknown. However, as the generation and accumulation of the amyloid Abeta peptide in the brain appears to be significant for the initiation and progression of AD, it is possible that cholesterol levels can regulate Abeta formation and/or clearance. To test the effects of altering cholesterol on Abeta formation, we incubated cells in the presence of lipid depleted serum, with or without the active metabolite of the HMG-CoA reductase inhibitor lovastatin. After confirming that cholesterol was depleted in the cells, we then measured the fraction of Abeta formed from its precursor betaPP under each condition. We observed that cholesterol depletion led to a profound decrease in the levels of Abeta released from the cells. This effect of lovastatin acid was observed at concentrations of 0.05-5 &mgr;M, ranges where this compound is effective at inhibiting HMG-CoA reductase, thereby inhibiting cholesterol synthesis. In contrast, the release of an additional AbetaPP fragment, AbetaPPs, was only modestly reduced by cholesterol treatment. In further studies, we determined that the decreased release of Abeta was not due to its accumulation in the cell, but rather due to decreased formation of Abeta. Finally, we were able to exclude decreased maturation (glycosylation and sulfation) of newly synthesized AbetaPP as a cause for the effects of lovastatin acid on betaPP processing and Abeta formation. Our results demonstrate that reducing cellular cholesterol by the use of an HMG-CoA reductase inhibitor regulates Abeta formation. This effect may involve alterations in the trafficking of AbetaPP and/or alterations in the activity of the proteases that cleave AbetaPP. The results suggest a mechanism by which hypercholesterolemia may increase risk for AD and indicate that reduction in cholesterol may delay the onset and/or slow the progression of AD.

Oestrogenic steroids and melanoma cell interaction with adjacent skin cells influence invasion of melanoma cells in vitro.

The invasion of melanoma is complex and multi-staged and involves changes in both cell/extracellular matrix (ECM) and cell/cell interactions. Female steroids and alpha-MSH have also been reported to influence metastatic melanoma progression, but their mechanisms of action are unknown. Accordingly, our aim was to establish in vitro models to examine (a) the influence of sex steroids and alpha-melanocyte-stimulating hormone (alpha-MSH) on tumour invasion and the influence of (b) ECM proteins and (c) adjacent cells on melanoma invasion. In the first model, melanoma cell invasion through fibronectin over 20 hr under serum-free conditions was used to investigate the effects of 17beta-oestradiol and oestrone on the invasion of human melanoma cell lines, A375-SM and HBL. A375-SM, but not HBL cells, proved very susceptible to inhibition by female steroids. However, invasion of the HBL line was inhibited by alpha-MSH. Using the second model of reconstructed human skin based on de-epidermised acellular dermis, we found that the HBL cells on their own failed to invade into the dermis (irrespective of the presence or absence of the basement membrane). However, there was a significant synergistic interaction between keratinocytes, fibroblasts and HBL cells, such that a modest invasion of HBLs into the dermis was seen within 2 weeks when other skin cells were present. In contrast, A375-SM cells showed a significant ability to invade the dermis in the absence of other cells, with less invasion when other skin cells were present. In summary, these models have provided new information on the extent to which melanoma cell invasion is sensitive to oestrogenic steroids and to alpha-MSH and to interaction, not only with adjacent skin cells but also to the presence of basement membrane antigens.

alpha-Melanocyte stimulating hormone inhibits tumour necrosis factor-alpha stimulated intercellular adhesion molecule-1 expression in normal cutaneous human melanocytes and in melanoma cell lines.

alpha-Melanocyte stimulating hormone (alpha-MSH) was found significantly to reduce tumour necrosis factor-alpha (TNF-alpha) stimulated upregulation of intercellular adhesion molecule-1 (ICAM-1) in normal adult cutaneous melanocytes. The maximum inhibitory response to alpha-MSH was obtained at around 10(-10) mol/L alpha-MSH when cells were coincubated with alpha-MSH and TNF-alpha for 24 h. alpha-MSH had little or no effect on basal ICAM-1 expression in melanocytes and the effects of alpha-MSH could be mimicked with 3-isobutyl-1-methylxanthine (IBMX). Preliminary data in three human melanoma cell lines also showed alpha-MSH and forskolin to be effective in significantly reducing TNF-alpha stimulated ICAM-1 expression over 24 h. The extent of the inhibition varied from cell line to cell line and was greatest in those cells with the highest number of alpha-MSH receptors. These data suggest that alpha-MSH has the ability to oppose the action of the pro-inflammatory cytokine TNF-alpha on melanocytes and melanoma cells.

Palliation of inoperable esophageal carcinoma with the Wallstent endoprosthesis.

BACKGROUND: Palliation of malignant dysphagia can be achieved by insertion of an endoprosthesis. Recently, metallic self-expanding prostheses have been introduced that offer the advantage of a lower complication rate over their plastic counterpart. METHODS: Thirteen patients with dysphagia due to inoperable carcinoma of the esophagus were treated with coated Wallstent (Schneider (USA) Inc, Minneapolis, MN) endoprostheses, which were placed under fluoroscopic control. All patients were given general anesthesia during the procedure. RESULTS: After successful insertion of all endoprostheses, the dysphagia of 12 of the patients improved while in the hospital. Average length of stay was 4.4 days. Two patients required a second stent because of migration or tumor overgrowth. Seven patients died with a mean survival of 54 days (range, 14 to 144 days), and 6 are alive a mean of 112 days (range, 32 to 263 days) after treatment. CONCLUSIONS: Coated Wallstent insertion is an effective, single treatment that quickly improves the patients' quality of life. Its effect on survival is yet to be established when used as a last resort in patients with inoperable esophageal carcinoma and poor general condition.

Investigation of calmodulin and basic fibroblast growth factor (bFGF) in idiopathic myelofibrosis: evidence for a role of extracellular calmodulin in fibroblast proliferation.

The urinary concentration of calmodulin and basic fibroblast growth factor (bFGF) was determined in a total of 53 patients with various chronic myeloproliferative disorders (CMPD), including 22 patients with idiopathic myelofibrosis (IMF). Calmodulin excretion was significantly elevated in IMF (0.29 +/- 0.04 microgram/mmol creatinine) (P < 0.001), when compared to polycythaemia vera (PV) (0.14 +/- 0.02), essential thrombocythaemia (ET) (0.13 +/- 0.04), chronic myeloid leukaemia (CML) (0.16 +/- 0.02), unclassified myeloproliferative disorders (UMPD) (0.11 +/- 0.02) and age-matched controls (0.1 +/- 0.02) (P < 0.001). In contrast, bFGF was slightly elevated in all CMPD conditions when compared to age-matched controls. A neutralizing antibody to calmodulin was demonstrated to significantly influence the in vitro proliferation of normal human fibroblasts, an effect dependent on both cell density and the presence of fetal calf serum (FCS). Essentially, the antibody reduced FCS-induced proliferation of low-density fibroblasts but had little or no inhibitory effect on high-density fibroblasts in the absence of FCS. In addition, extracellular calmodulin was shown not to interact with known fibroblast mitogens, namely, IFG-1, EGF, bDGF and PDGF. We conclude that extracellular calmodulin should be considered, in addition to PDGF, TFG-beta and EGF, as a potential mitogen involved in the stromal reaction of idiopathic myelofibrosis.

Identification of neurofibromatosis 1 (NF1) homologous loci by direct sequencing, fluorescence in situ hybridization, and PCR amplification of somatic cell hybrids.

Using fluorescence in situ hybridization (FISH), we have identified seven NF1-related loci, two separate loci on chromosome 2, at bands 2q21 and 2q33-q34, and one locus each on five other chromosomes at bands 14q11.2, 15q11.2, 18p11.2, 21q11.2-q21, and 22q11.2. Application of PCR using NF1 primer pairs and genomic DNA from somatic cell hybrids confirmed the above loci, identified additional loci on chromosomes 12 and 15, and showed that the various loci do not share homology beyond NF1 exon 27b. Sequenced PCR products representing segments corresponding to NF1 exons from these loci demonstrated greater than 95% sequence identity with the NF1 locus. We used sequence differences between bona fide NF1 and NF1-homologous loci to strategically design primer sets to specifically amplify 30 of 36 exons within the 5' end of the NF1 gene. These developments have facilitated mutation analysis at the NF1 locus using genomic DNA as template.