Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications

Platelets have a central role in the development of arterial thrombosis and subsequent cardiovascular events. An appreciation of this complex process has made antiplatelet therapy the cornerstone of cardiovascular disease management. However, numerous patients will experience a recurrent atherothrombotic vascular event despite adequate antiplatelet therapy. Individual differences in the rate of platelet activation and reactivity markedly influence normal hemostasis and the pathological outcome of thrombosis. Such an individual variability is largely determined by environmental and genetic factors. These are known to either hamper platelets' response to agonists, and thereby mimic the pharmacological modulation of platelet function or mask therapy effect and sensitize platelets. In this article, we reviewed the antiplatelet mechanisms of aspirin and clopidogrel and the possible role of different polymorphisms, which may affect the efficacy of antiplatelet therapy. Heterogeneity in the way patients respond to aspirin and clopidogrel may in part reflect variation in cyclooxygenase (COX)-1, COX-2, glycoprotein (GP) Ib alpha, GP Ia/IIa, GP IIb/IIIa, UGT1A6*2, P2Y₁, P2Y₁₂, CYP2C9, CYP3A4 and CYP3A5 genotypes.     

APRIL secreted by neutrophils binds to heparan sulfate proteoglycans to create plasma cell niches in human mucosa

The bone marrow constitutes a favorable environment for long-lived antibody-secreting plasma cells, providing blood-circulating antibody. Plasma cells are also present in mucosa-associated lymphoid tissue (MALT) to mediate local frontline immunity, but how plasma cell survival there is regulated is not known. Here we report that a proliferation-inducing ligand (APRIL) promoted survival of human upper and lower MALT plasma cells by upregulating expression of the antiapoptotic proteins bcl-2, bcl-xL, and mcl-1. The in situ localization of APRIL was consistent with such a prosurvival role in MALT. In upper MALT, tonsillar epithelium produced APRIL. Upon infection, APRIL production increased considerably when APRIL-secreting neutrophils recruited from the blood infiltrated the crypt epithelium. Heparan sulfate proteoglycans (HSPGs) retained secreted APRIL in the subepithelium of the infected zone to create APRIL-rich niches, wherein IgG-producing plasma cells accumulated. In lower MALT, neutrophils were the unique source of APRIL, giving rise to similar niches for IgA-producing plasmocytes in villi of lamina propria. Furthermore, we found that mucosal humoral immunity in APRIL-deficient mice is less persistent than in WT mice. Hence, production of APRIL by inflammation-recruited neutrophils may create plasma cell niches in MALT to sustain a local antibody production.     

Anti-proliferative effect of Euphorbia stenoclada in human airway smooth muscle cells in culture

The ethanolic extract of a Malagasy species Euphorbia stenoclada (ES) (Euphorbiaceae), traditionally used as a herbal remedy against asthma and acute bronchitis, was tested to evaluate possible anti-proliferative activity on human airway smooth muscle cells (HASMC). The ES ethanolic extract totally abolished the interleukin-1beta (IL-1beta) induced proliferation of HASMC (IC(50)=0.73+/-0.08 microg/mL). No cytotoxic effect was observed up to 20 microg/mL. A bioassay-guided fractionation of the ethanolic extract was performed by reversed-phase (RP) flash chromatography, giving five fractions (FA to FE) where fraction FE was the only active one (IC(50)=0.38+/-0.02 microg/mL). The purification of this bioactive fraction FE was carried out by RP-HPLC affording six sub-fractions 1-6, and only sub-fraction 5 kept the anti-proliferative activity. Its major constituent was identified as quercetin (IC(50)=0.49+/-0.12 microg/mL) by means of HPLC/UV/MS and co-elution with the authentic standard. Quercitrin was also identified in the fraction FE but was inactive. A structure-activity relationship with flavonols determined that methylation reduced the anti-proliferative activity whereas glycosylation abolished it. The present study shows that the anti-proliferative properties of Euphorbia stenoclada are mediated through the presence of quercetin that may explain the traditional use of this plant as a remedy against asthma.     

A study of five human cytokine genes in human essential hypertension

With a view to evaluating the putative involvement of cytokine gene variants in human essential hypertension, we carried out an association (case-control) study on 174 unrelated nationals (81 hypertensives and 93 normotensives) from the Abu Dhabi Emirate (UAE), a genetically homogeneous population also characterised by the absence of traditional confounding factors such as alcohol consumption and smoking. To that end, we targeted our investigation to five candidate gene loci-transforming growth factor beta1 (TGF-beta1), interferon gamma (IFN-gamma), epidermal growth factor (EGF), interleukin-1 beta (IL-1beta) and tumour-necrosis factor (TNF-alpha) genes. We investigated the distribution of genotypes and alleles of the six following dimorphic variants: TGF-beta1(*)10(T>C) and TGF-beta1(*)25(G>C), located at codons 10 and 25, respectively, of TGF-beta1; T874A in intron 1 of IFN-gamma; G61A in exon 1 of EGF; TaqI dimorphism at +3962 (exon 5) of IL-1beta; and -308A>G in the promoter of TNF-alpha. These six bi-allelic markers were visualised by methods based on the techniques of amplification refractory mutation system-polymerase chain reaction (for TGF-beta1, IFN-gamma, EGF and TNF-alpha) and by polymerase chain reaction-TaqI restriction endonuclease analysis in the case of IL-1beta.In each of the two groups (normotensives and hypertensives), genotype frequencies of all six markers occurred in Hardy-Weinberg proportions. There were, however, no statistical differences in the allele and genotype frequencies of any of the six markers between the two groups of subjects: TGF-beta1(*)10C frequencies were 0.46 and 0.49 (chi(2)=0.61; 2 d.f.; P=0.74) and TGF-beta1(*)25C were 0.07 and 0.08 (chi(2)=0.61; 2 d.f.; P=0.74) amongst normotensives and hypertensives, respectively; p(IFN-gamma(*)A874) were 0.41 in normotensives versus 0.46 in hypertensives (chi(2)=3.07; 2 d.f.; P=0.22); p(EGF (*)G61) were 0.51 versus 0.58 (chi(2)=1.76; 2 d.f.; P=0.41); p[IL-1beta (*)TaqI(+)] were 0.43 versus 0.36 (chi(2)=2.08; 2 d.f.; P=0.35); and p(TNF-alpha(*)-308G) were 0.80 versus 0.85 (chi(2)=1.29; 2 d.f.; P=0.53). There was also no difference in distribution and frequencies of haplotypes constructed with combinations of TGF-beta1(*)10(T>C) and TGF-beta1(*)25(G>C) sites. However, although they do not reach statistical significance (which may be due to the relatively restricted number of subjects included in this study), the distribution differences (in normotensives and hypertensives) observed in the cases of EGF and TNF-alpha reflect trends that could be expected from a mechanistic explanation of the pathways that underlie the patho-physiology of hypertension.     

Identification of ANKRD11 and ZNF778 as candidate genes for autism and variable cognitive impairment in the novel 16q24.3 microdeletion syndrome

The clinical use of array comparative genomic hybridization in the evaluation of patients with multiple congenital anomalies and/or mental retardation has recently led to the discovery of a number of novel microdeletion and microduplication syndromes. We present four male patients with overlapping molecularly defined de novo microdeletions of 16q24.3. The clinical features observed in these patients include facial dysmorphisms comprising prominent forehead, large ears, smooth philtrum, pointed chin and wide mouth, variable cognitive impairment, autism spectrum disorder, structural anomalies of the brain, seizures and neonatal thrombocytopenia. Although deletions vary in size, the common region of overlap is only 90 kb and comprises two known genes, Ankyrin Repeat Domain 11 (ANKRD11) (MIM 611192) and Zinc Finger 778 (ZNF778), and is located approximately 10 kb distally to Cadherin 15 (CDH15) (MIM 114019). This region is not found as a copy number variation in controls. We propose that these patients represent a novel and distinctive microdeletion syndrome, characterized by autism spectrum disorder, variable cognitive impairment, facial dysmorphisms and brain abnormalities. We suggest that haploinsufficiency of ANKRD11 and/or ZNF778 contribute to this phenotype and speculate that further investigation of non-deletion patients who have features suggestive of this 16q24.3 microdeletion syndrome might uncover other mutations in one or both of these genes.     

Mineral balance and whole body bone mineral content in very low-birth-weight infants

Fat and mineral metabolic balance studies were performed in 25 normal very low-birth-weight infants ( 1500 g at birth) fed either pooled pasteurized human milk supplemented with calcium, phosphorus and magnesium, or a preterm formula. Calcium, phosphorus and magnesium intake were similar in both groups and averaged 100mg/kg/day, 72 mg/kg/day and 8 mg/kg/day, respectively. Calcium and phosphorus retention was higher in the subjects fed fortified human milk than in those receiving a preterm formula (65±14 and 62±9mg/kg/day versus 55±12 and 47±7mg/kg/day respectively). The difference was only significant for phosphorus. Magnesium retention was similar in the two groups and averaged 3 mg/kg/day. Fat intake and absorption was significantly higher in the preterm formula fed group than in the one fed fortified human milk (5.5±0.4 g/kg/day and 88±4% versus 4.2±1 g/kg/day, 79±6% respectively). Assessment of the whole body bone mineral content by dual energy X-ray absorptiometry was performed at 3 and 6 months of age in another group of 25 low-birth-weight infants fed either fortified human milk or a preterm formula. Whole body bone mineral content (BMCt) was low (43.3±30.8 g of hydroxyapatite) at 3 months of age (theoretical term) compared to normal full-term newborns at birth. There was no significant influence of the diet. At 6 months of age, BMCt reached 168.6±36.6g, a value similar to that of full-term newborns, with no significant difference between the two regimen groups. The deficit in the 12 subjects who had a BMCt under 30 g at 3 months of age had been corrected at age 6 months. Premature babies fed a pooled pasteurized human milk enriched with calcium, phosphorus and magnesium favored a better retention of calcium and phosphorus. However, no significant influence of the two diets studied was observed on the gain in BMCt over the first 6 months of life.