Ultrastructure of cell death in bulbar cushions of chick embryo heart

Summary The ultrastructure of the physiological cell death was studied in distal ventral bulbar cushions of 15 chick embryo hearts on the 4th and 5th day of incubation. Microperfusion fixation was performed. The ultracytochemistry of a lysosomal hydrolytic enzyme acid phosphatase was also investigated in another 15 embryonic hearts.In the course of the cell degeneration an increase in cellulr autophagy was observed without previous cytoplasmic or nuclear changes or phagocyte ingestion. A cytoplasmic diffusion of acid phosphatase outside of lysosomes was observed.Besides the cell death with the marked participation of the lysosomal system, another kind of dying cells was found, characterized by their nuclear pycnosis and cytoplasmic condensation. Starting from the 5th day of incubation the dying and dead cells were found phagocytized by some of their neighbouring viable mesenchymal cells. A formation of ribosomal crystals was not observed.The formation and fate of cytolysomes as well as the fate of phagocytes are discussed. The presence of pre-necrotic cells with important autophagy and of necrotic cells with nuclear changes was related to the possibility of a dual cause of the cell death. In the case of pre-necrotic cells the epigenetic factors like the biomechanic action of hemodynamics were considered, while the necrotic cells seem to be programmed to death by their genome.Finally the uniformity of cell death ultrastructure in different organs and species was noticed.     

Intrauterine insemination treatment in subfertility: an analysis of factors affecting outcome

A total of 811 intrauterine insemination (IUI) cycles in which clomiphene citrate/human menopausal gonadotrophin (HMG) was used for ovarian stimulation were analysed retrospectively to identify prognostic factors regarding treatment outcome. The overall pregnancy rate was 12.6% per cycle, the multiple pregnancy rate 13.7%, and the miscarriage rate 23.5%. Logistic regression analysis revealed five predictive variables as regards pregnancy: number of the treatment cycle (P = 0.009), duration of infertility (P = 0.017), age (P = 0.028), number of follicles (P = 0.031) and infertility aetiology (P = 0.045). The odds ratios for age < 40 years, unexplained infertility aetiology (versus endometriosis) and duration of infertility < or = 6 years were 3.24, 2.79 and 2.33, respectively. A multifollicular ovarian response to clomiphene citrate/HMG resulted in better treatment success than a monofollicular response, and 97% of the pregnancies were obtained in the first four treatment cycles. The results indicate that clomiphene citrate/HMG/IUI is a useful and cost-effective treatment option in women < 40 years of age with infertility duration < or = 6 years, who do not suffer from endometriosis.     

Nuclear receptor NR2E3 gene mutations distort human retinal laminar architecture and cause an unusual degeneration

Mutations in the nuclear receptor gene, NR2E3, cause a disorder of human retinal photoreceptor development characterized by hyperfunction and excess of the minority S (short wavelength or blue) cone photoreceptor type, but near absence of function of the majority rod receptor. NR2E3 disease can also progress to blindness. How the human retina accommodates mis-specified types and numbers of neurons and advances to retinal degeneration are unknown. We studied the retinal organization in vivo of patients with NR2E3 mutations. Early human NR2E3 disease with S cone hyperfunction showed thickened retinal layers within an otherwise normally structured retina. With visual loss, however, lamination was coarse and there was a strikingly thick and bulging appearance to the retina, localized to an annulus encircling the central fovea. This pattern was not found in other retinal degenerations. The abnormal laminar retinal architecture of early NR2E3 disease may be due in part to larger cells with an S cone phenotype in place of rods that failed to differentiate. The later-stage dysplastic appearance suggests a previously unrecognized proliferative response in human retinal degeneration.     

Apoptosis of Merkel cells in neurotrophin-3 null mice

Postnatal mice lacking neurotrophin-3 (NT3) are deficient in Merkel cells of touch domes and whisker follicles. We examined the mechanism of Merkel cell loss by immunocytochemistry and electron microscopy. Merkel cell of whisker follicles of NT3 null newborns exhibited decreased immunoreactivity for cytokeratin 8 and contained apoptotic bodies that were positive for cleaved caspase-3, a marker of active apoptosis. By electron microscopy, the Merkel cells displayed aggregation of chromatin along the nuclear membrane, with the marginated chromatin forming caps at the periphery of the nucleus. Ribosomes aggregated in the cytoplasm, while dense core granules characteristic of Merkel cells were still discernible. Finally, the Merkel cells and their nuclei fragmented into apoptotic bodies. None of the apoptotic Merkel cells were contacted by nerve fibers, and their desmosomal contacts with surrounding keratinocytes disappeared. After postnatal day 6 apoptotic Merkel cells were no longer observed, and the number of surviving Merkel cells was severely reduced. They were flat and contained few osmiophilic granules. We conclude that perinatal apoptosis is responsible for the loss of Merkel cells lacking innervation in NT3 null mice.     

Krill Oil Supplementation Reduces Exacerbated Hepatic Steatosis Induced by Thermoneutral Housing in Mice with Diet-Induced Obesity

Preclinical evidence suggests that n-3 fatty acids EPA and DHA (Omega-3) supplemented as phospholipids (PLs) may be more effective than triacylglycerols (TAGs) in reducing hepatic steatosis. To further test the ability of Omega-3 PLs to alleviate liver steatosis, we used a model of exacerbated non-alcoholic fatty liver disease based on high-fat feeding at thermoneutral temperature. Male C57BL/6N mice were fed for 24 weeks a lard-based diet given either alone (LHF) or supplemented with Omega-3 (30 mg/g diet) as PLs (krill oil; ω3PL) or TAGs (Epax 3000TG concentrate; ω3TG), which had a similar total content of EPA and DHA and their ratio. Substantial levels of TAG accumulation (~250 mg/g) but relatively low inflammation/fibrosis levels were achieved in the livers of control LHF mice. Liver steatosis was reduced by >40% in the ω3PL but not ω3TG group, and plasma ALT levels were markedly reduced (by 68%) in ω3PL mice as well. Krill oil administration also improved hepatic insulin sensitivity, and its effects were associated with high plasma adiponectin levels (150% of LHF mice) along with superior bioavailability of EPA, increased content of alkaloids stachydrine and trigonelline, suppression of lipogenic gene expression, and decreased diacylglycerol levels in the liver. This study reveals that in addition to Omega-3 PLs, other constituents of krill oil, such as alkaloids, may contribute to its strong antisteatotic effects in the liver.     

Dietary Supplementation with Selenium and Coenzyme Q10 Prevents Increase in Plasma D-Dimer While Lowering Cardiovascular Mortality in an Elderly Swedish Population

A low intake of selenium is associated with increased cardiovascular mortality. This could be reduced by supplementation with selenium and coenzyme Q₁₀. D-dimer, a fragment of fibrin mirroring fibrinolysis, is a biomarker of thromboembolism, increased inflammation, endothelial dysfunction and is associated with cardiovascular mortality in ischemic heart disease. The objective was to examine the impact of selenium and coenzyme Q₁₀ on the level of D-dimer, and its relationship to cardiovascular mortality. D-dimer was measured in 213 individuals at the start and after 48 months of a randomised double-blind placebo-controlled trial with selenium yeast (200 µg/day) and coenzyme Q₁₀ (200 mg/day) (n = 106) or placebo (n = 107). The follow-up time was 4.9 years. All included individuals were low in selenium (mean 67 μg/L, SD 16.8). The differences in D-dimer concentration were evaluated by the use of T-tests, repeated measures of variance and ANCOVA analyses. At the end, a significantly lower D-dimer concentration was observed in the active treatment group in comparison with those on placebo (p = 0.006). Although D-dimer values at baseline were weakly associated with high-sensitive CRP, while being more strongly associated with soluble tumour necrosis factor receptor 1 and sP-selectin, controlling for these in the analysis there was an independent effect on D-dimer. In participants with a D-dimer level above median at baseline, the supplementation resulted in significantly lower cardiovascular mortality compared to those on placebo (p = 0.014). All results were validated with a persisting significant difference between the two groups. Therefore, supplementation with selenium and coenzyme Q₁₀ in a group of elderly low in selenium and coenzyme Q₁₀ prevented an increase in D-dimer and reduced the risk of cardiovascular mortality in comparison with the placebo group. The obtained results also illustrate important associations between inflammation, endothelial function and cardiovascular risk.     

The changing landscape of percutaneous technology leading to surgical complications

With new technology comes new complications. We discuss the interesting case presented by Bjelic and colleagues regarding a misplaced TAVR (transcatheter aortic valve replacement) valve into the inflow cannula of a left ventricular assist device, leading to hemodynamic collapse. The author describes the pitfalls of the new technology and interesting surgical maneuvers to address these complications.