Putative association of a mutant ROM1 allele with retinitis pigmentosa

Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous form of retinal degeneration. Several genes and loci have been shown to be involved in the disease, although each of them only accounts for a few cases. Mutations in the gene encoding ROM1, a rod-specific protein, have been putatively associated with several forms of RP. Here we describe a double-mutant allele of this gene, P60T and T108M, present in two affected sibs and also in two healthy members of a Spanish RP family. The same double-mutant allele was previously considered to be responsible for autosomal dominant RP in one family. We now report data that question the potential pathogenicity of these two ROM1 mutations. Received: 30 July 1996 / Revised: 13 December 1996     

Monocyte chemoattractant protein-1 in obesity and type 2 diabetes. Insulin sensitivity study

Objective: Our goal was to test any association between human plasma circulating levels of monocyte chemoattractant protein‐1 (cMCP‐1) and insulin resistance and to compare monocyte chemoattractant protein‐1 (MCP‐1) adipose tissue gene expression and cMCP‐1 in relation with inflammatory markers. Research Methods and Procedures: cMCP‐1 was measured in n = 116 consecutive control male subjects to whom an insulin sensitivity (S_i) test was performed. Circulating levels of soluble CD14, soluble tumor necrosis factor receptor type 2 (sTNFR2), soluble interleukin‐6 (sIL‐6), and adiponectin also were measured. Subcutaneous adipose tissue samples were obtained from n = 107 non‐diabetic and type 2 diabetic subjects with different degrees of obesity. Real‐time polymerase chain reaction was used to measure gene expression of MCP‐1, CD68, tumor necrosis factor‐α (TNF‐α), and its receptor TNFR2. Results: In the S_i study, no independent effect of cMCP‐1 levels on insulin sensitivity was observed. In the expression study, in non‐diabetic subjects, MCP‐1 mRNA had a positive correlation with BMI (r = 0.407, p = 0.003), TNF‐α mRNA (r = 0.419, p = 0.002), and TNFR2 mRNA (r = 0.410, p = 0.003). In these subjects, cMCP‐1 was found to correlate with waist‐to‐hip ratio (r = 0.322, p = 0.048). In patients with type 2 diabetes, MCP‐1 mRNA was up‐regulated compared with non‐diabetic subjects. TNF‐α mRNA was found to independently contribute to MCP‐1 mRNA expression. In this group, CD68 mRNA was found to correlate with BMI (r = 0.455, p = 0.001). Discussion: cMCP‐1 is not associated with insulin sensitivity in apparently healthy men. TNF‐α is the inflammatory cytokine associated with MCP‐1 expression in subcutaneous adipose tissue.     

The effect of medicated diets and level of feeding on caecal microbiota of lactating rabbit does

AIMS: To study the effect of the type of antibiotic used in medicated diets against pathogens and the feeding level on the microbial biodiversity in the rabbit caecum. METHODS AND RESULTS: Three groups of eight does were given a diet unsupplemented (NAB) or with 100 ppm of bacitracin (BAC) or tiamulin (TIA). Litter sizes of four does in each group were adjusted to five (LS5) or to nine (LS9), to manipulate their levels of feed intake. The feeding level strongly affected caecal microbiota in does fed on NAB and BAC diet, whereas the effect of the antibiotic was higher in TIA-supplemented animals, even prevailing over the effect of feeding level. Daily food intake and milk yield (P<0.05) and caecum weight (P<0.10) were higher in feeding of LS9 does. The total volatile fatty acid concentration was lower with BAC (P<0.05). CONCLUSIONS: The feeding level strongly affects caecal biodiversity in lactating does. The extent of the antibiotic effect depends on its nature, being significant with TIA but not with BAC. SIGNIFICANCE AND IMPACT OF THE STUDY: Changes in the feeding level promote different profiles of caecal microbiota. Therapeutic doses of TIA may affect caecal microbiota, whereas BAC would not reduce diversity.     

Pretreatment with statins improves early outcome in patients with first-ever ischaemic stroke: a pleiotropic effect of statins or a beneficial effect of hypercholesterolemia?

Background

Data from different studies suggest a favourable association between pretreatment with statins or hypercholesterolemia and outcome after ischaemic stroke. We examined whether there were differences in in-hospital mortality according to the presence or absence of statin therapy in a large population of first-ever ischaemic stroke patients and assessed the influence of statins upon early death and spontaneous neurological recovery.

Methods

In 2,082 consecutive patients with first-ever ischaemic stroke collected from a prospective hospital-based stroke registry during a period of 19 years (1986-2004), statin use or hypercholesterolemia before stroke was documented in 381 patients. On the other hand, favourable outcome defined as grades 0-2 in the modified Rankin scale was recorded in 382 patients.

Results

Early outcome was better in the presence of statin therapy or hypercholesterolemia (cholesterol levels were not measured) with significant differences between the groups with and without pretreatment with statins in in-hospital mortality (6% vs 13.3%, P = 0.001) and symptom-free (22% vs 17.5%, P = 0.025) and severe functional limitation (6.6% vs 11.5%, P = 0.002) at hospital discharge, as well as lower rates of infectious respiratory complications during hospitalization. In the logistic regression model, statin therapy was the only variable inversely associated with in-hospital death (odds ratio 0.57) and directly associated with favourable outcome (odds ratio 1.32).

Conclusions

Use of statins or hypercholesterolemia before first-ever ischaemic stroke was associated with better early outcome with a reduced mortality during hospitalization and neurological disability at hospital discharge. However, statin therapy may increase the risk of intracerebral haemorrhage, particularly in the setting of thrombolysis.

     

Genetic fine localization of the arrestin (S-antigen) gene 4 cM distal from D2S172

Arrestin is a component of the light transduction cascade that takes place in the outer segment of retinal rods. In situ hybridization and linkage analysis have localized the arrestin gene to a region of 50 cM between CRYG and D2S23/D2S55 on chromosome 2q24–37. We have performed pairwise and multipoint linkage analysis between arrestin and four highly polymorphic markers from this region. The results indicate tight linkage between the gene and the microsatellite D2S172 (Z _max = 9.25 at =0.038). This fine localization of the gene should provide a useful tool for cosegregation analyses involving the arrestin gene.     

Distinct Roles of the Phosphatidate Phosphatases Lipin 1 and 2 during Adipogenesis and Lipid Droplet Biogenesis in 3T3-L1 Cells

Lipins are evolutionarily conserved Mg²⁺-dependent phosphatidate phosphatase (PAP) enzymes with essential roles in lipid biosynthesis. Mammals express three paralogues: lipins 1, 2, and 3. Loss of lipin 1 in mice inhibits adipogenesis at an early stage of differentiation and results in a lipodystrophic phenotype. The role of lipins at later stages of adipogenesis, when cells initiate the formation of lipid droplets, is less well characterized. We found that depletion of lipin 1, after the initiation of differentiation in 3T3-L1 cells but before the loading of lipid droplets with triacylglycerol, results in a reciprocal increase of lipin 2, but not lipin 3. We generated 3T3-L1 cells where total lipin protein and PAP activity levels are down-regulated by the combined depletion of lipins 1 and 2 at day 4 of differentiation. These cells still accumulated triacylglycerol but displayed a striking fragmentation of lipid droplets without significantly affecting their total volume per cell. This was due to the lack of the PAP activity of lipin 1 in adipocytes after day 4 of differentiation, whereas depletion of lipin 2 led to an increase of lipid droplet volume per cell. We propose that in addition to their roles during early adipogenesis, lipins also have a role in lipid droplet biogenesis.