Hypertrophic cardiomyopathy: two homozygous cases with "typical" hypertrophic cardiomyopathy and three new mutations in cases with progression to dilated cardiomyopathy

About 10% of cases of hypertrophic cardiomyopathy (HCM) evolve into dilated cardiomyopathy (DCM) with unknown causes. We studied 11 unrelated patients (pts) with HCM who progressed to DCM (group A) and 11 who showed "typical" HCM (group B). Mutational analysis of the beta-myosin heavy chain (MYH7), myosin-binding protein C (MYBPC3), and cardiac troponin T (TNNT2) genes demonstrated eight mutations affecting MYH7 or MYBPC3 gene, five of which were new mutations. In group A-pts, the first new mutation occurred in the myosin head-rod junction and the second occurred in the light chain-binding site. The third new mutation leads to a MYBPC3 lacking titin and myosin binding sites. In group B, two pts with severe HCM carried two homozygous MYBPC3 mutations and one with moderate hypertrophy was a compound heterozygous for MYBPC3 gene. We identified five unreported mutations, potentially "malignant" defects as for the associated phenotypes, but no specific mutations of HCM/DCM.     

Mandibuloacral dysplasia is caused by a mutation in LMNA-encoding lamin A/C

Mandibuloacral dysplasia (MAD) is a rare autosomal recessive disorder, characterized by postnatal growth retardation, craniofacial anomalies, skeletal malformations, and mottled cutaneous pigmentation. The LMNA gene encoding two nuclear envelope proteins (lamins A and C [lamin A/C]) maps to chromosome 1q21 and has been associated with five distinct pathologies, including Dunnigan-type familial partial lipodystrophy, a condition that is characterized by subcutaneous fat loss and is invariably associated with insulin resistance and diabetes. Since patients with MAD frequently have partial lipodystrophy and insulin resistance, we hypothesized that the disease may be caused by mutations in the LMNA gene. We analyzed five consanguineous Italian families and demonstrated linkage of MAD to chromosome 1q21, by use of homozygosity mapping. We then sequenced the LMNA gene and identified a homozygous missense mutation (R527H) that was shared by all affected patients. Patient skin fibroblasts showed nuclei that presented abnormal lamin A/C distribution and a dysmorphic envelope, thus demonstrating the pathogenic effect of the R527H LMNA mutation.     

Differential microbial clearance and immunoresponse of Balb/c (Nramp1 susceptible) and DBA2 (Nramp1 resistant) mice intracerebrally infected with Mycobacterium bovis BCG (BCG)

In mice, the gene encoding Nramp1 (natural resistance-associated protein 1) exists in two allelic forms, differing for a point mutation. According to Nramp1 genotype, extensive literature documents a clear-cut distinction of inbred strains in two non-overlapping groups that phenotypically express resistance (Nramp1r) and susceptibility (Nramp1s) to systemic infections. Here, we provide evidence that Nramp1r (DBA/2) and Nramp1s (Balb/c) mice differently handle intracerebral infection with Mycobacterium bovis BCG. Distinct trends of microbial clearance from the brain and also different patterns of local immune responses occur, thus arguing on the involvement of Nramp1 gene product on the accomplishment of cerebral anti-mycobacterial defenses.     

Absence of endogenous interleukin-10 enhances the evolution of acute lung injury

Interleukin-10 (IL-10) exerts a wide spectrum of regulatory activities in the immune and inflammatory response. The aim of this study was to investigate the role of endogenous IL-10 on the modulation of the inflammatory response in mice subjected to carrageenan-induced lung injury. When compared to carrageenan-treated IL-10 wild-type (WT) mice, carrageenan-treated IL-10 knock-out mice (IL-10KO) mice experienced a higher rate of pleural exudation, and polymorphonuclear cell migration. Exudate levels of the pro-inflammatory cytokines tumour necrosis factor, interleukin-1beta and interleukin-6 were also greatly enhanced in IL-10KO mice in comparison to wild-type mice. Lung myeloperoxidase (MPO) activity was significantly reduced in IL-10WT mice when compared to IL-10KO mice-treated with carrageenan. The degree of oxidative and nitrosative damage was significantly higher in IL-10KO mice than in wild-type littermates, as indicated by elevated malondialdehyde levels and formation of nitrotyrosine and poly (ADP-ribose) synthetase (PARS). Staining of lung tissue sections obtained from carrageenan-treated IL-10WT with an anti-COX-2 antibody showed a positive staining of the inflamed tissue. Furthermore, expression of inducible nitric oxide synthase (iNOS) was found mainly in the macrophages of the inflamed lungs from carrageenan-treated IL-10WT mice. The intensity and degree of the staining for COX-2 and iNOS were markedly enhanced in tissue sections obtained from carrageenan-treated IL-10KO mice. Most notably, the degree of lung injury caused by carrageenan was also enhanced in IL-10KO mice. Taken together, our results clearly demonstrate that endogenous IL-10 exerts an anti-inflammatory role during acute inflammation and tissue damage associated with carrageenan-induced pleurisy, possibly by regulating neutrophil recruitment, and the subsequent cytokine and oxidant generation.     

beta-Endorphin modulation of pressor response to hyperventilation in hypertensive patients

After hyperventilation, systolic and diastolic blood pressure (BP) significantly decreased in 14 hypertensive patients (group 1), did not change in 9 (group 2) and increased in 8 (group 3). Basal BP, norepinephrine and dynorphin B levels were higher in group 1 than in groups 2 and 3. The decrease in BP after hyperventilation was associated with a decrease in plasma norepinephrine, Met-enkephalin and dynorphin B and an increase in beta-endorphin. Naloxone abolished the hyperventilation-induced BP and norepinephrine decreases. Our findings indicate that hyperventilation may select hypertensive patients with different sympatho-adrenergic activity and that the increase in beta-endorphin reduces BP response to hyperventilation in patients with high sympatho-adrenergic tone.     

Archaeobotanical investigations in Liguria: preliminary data on the early Iron Age at Monte Trabocchetto (Pietra Ligure,Italy)

The archaeological site we studied is part of an early Iron Age hill fort (8th/7th cent. b.c.), located 800 m from the coast on the top of a hill named MonteTrabocchetto. This paper concerns an excavation, called saggio O, which disclosed a very varied stratigraphy characterised by highly anthropogenic layers and by a pit, presumably used as a silo for food storage, which was very rich in charred seeds and fruits. The study of the pit content showed the dominance of Hordeum vulgare, while Triticum dicoccon, T. monococcum, T. aestivum/durum, Panicum miliaceum and Setaria italica were less strongly represented. Some edible Leguminosae were also found (Lens culinaris, Vicia faba var. minor and V. ervilia). In the frequented areas around the pit, herbaceous weeds and fruit tree macro-remains were present (Prunus cf. spinosa, Corylus avellana, Quercus sp. and Vitis vinifera ssp. sylvestris). The identification of a large number of botanical taxa has provided important information on food of plant origin and agricultural practices during the early Iron Age on the Ligurian coast, the proto-historic archaeobotanical aspects of which are largely unknown.     

Identification of a novel type IV pilus gene cluster required for gastrointestinal colonization of Citrobacter rodentium

Citrobacter rodentium is used as an in vivo model system for clinically significant enteric pathogens such as enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). These pathogens all colonize the lumen side of the host gastrointestinal tract via attaching and effacing (A/E) lesion formation. In order to identify genes required for the colonization of A/E-forming pathogens, a library of signature-tagged transposon mutants of C. rodentium was constructed and screened in mice. Of the 576 mutants tested, 14 were attenuated in their ability to colonize the descending colon. Of these, eight mapped to the locus of enterocyte effacement (LEE), which is required for the formation of A/E lesions, underlying the importance of this mechanism for pathogenesis. Another mutant, P5H2, was found to have a transposon insertion in an open reading frame that has strong similarity to type IV pilus nucleotide-binding proteins. The region flanking the transposon insertion was sequenced, identifying a cluster of 12 genes that encode the first described pilus of C. rodentium (named colonization factor Citrobacter, CFC). The proteins encoded by cfc genes have identity to proteins of the type IV COF pilus of enterotoxigenic E. coli (ETEC), the toxin co-regulated pilus of Vibrio cholerae and the bundle-forming pilus of EPEC. A non-polar mutation in cfcI, complementation of this strain with wild-type cfcI and complementation of strain P5H2 with wild-type cfcH confirmed that these genes are required for colonization of the gastrointestinal tract by C. rodentium. Thus, CFC provides a convenient model to study type IV pilus-mediated pathogen-host interactions under physiological conditions in the natural colonic environment.     

A Regulatory Mutant of Hansenula polymorpha Exhibiting Methanol Utilization Metabolism and Peroxisome Proliferation in Glucose

Mutant LGM-128 of Hansenula polymorpha harbors the recessive mutation glr2-1 which confers a complex pleiotropic phenotype, the major feature of which is the metabolically unnecessary induction of methanol utilization metabolism (C₁ metabolism) during growth on glucose, whether or not methanol is in the medium. Therefore, in this mutant, peroxisomes are formed and proliferate upon cultivation in glucose-containing media. In these media, LGM-128 shows induction levels of C₁ metabolism that are similar to those observed in methanol-containing media. This indicates that GLR2 controls the repression-derepression process stimulated by glucose and that the induction process triggered by methanol plays only a minor role in activating C₁ metabolism. Cultivating LGM-128 in methanol and then transferring it to glucose media revealed that active degradative processes occur, leading to the disappearance of C₁ metabolism. This observation suggests that, although stimulated by glucose, the two processes are controlled by elements which are, at least in part, distinct. Finally, glr2-1 does not affect ethanol repression, suggesting that in H. polymorpha the two repressing circuits are separated.