[Effects of internal limiting membrane peeling in epiretinal membrane surgery on OCT-angiography]. / Effets du pelage de la membrane limitante interne sur la microvascularisation maculaire en OCT-angiographie dans la chirurgie des membranes épirétiniennes.

PURPOSE: To assess macular microvascular parameters using OCT-angiography (OCT-A) in idiopathic epiretinal membrane surgery with or without internal limiting membrane peeling. MATERIALS AND METHODS: We retrospectively studied 17 eyes of 17 patients who underwent vitrectomy surgery for idiopathic epiretinal membrane with (n=10) or without (n=7) internal limiting membrane peeling. Patients operated on between July 2020 and June 2022 at the Colmar Hospital (France) by a single surgeon were evaluated before and 1 month after surgery, using OCT-A (Spectralis OCT-A module, Heidelberg Engineering®, Germany). The parameters studied were the area, perimeter and acircularity index of the foveal avascular zone (FAZ), the foveolar (FVD) and parafoveolar (PRVD) perfusion density and the macular vessel density ratio (MVR) in the superficial vascular complex (SVC) and the deep vascular complex (DVC). These parameters were measured using ImageJ software (National Institutes of Health, Bethesda, Maryland, USA). RESULTS: We found no statistically significant difference between the two groups postoperatively in either area, perimeter, or acircularity index of the FAZ, FVD, PRVD, or MVR in either the SVC or DVC. CONCLUSION: Our results with regard to macular microvasculature demonstrate no difference related to peeling of the internal limiting membrane and thus do not argue against this practice during epiretinal membrane surgery.

[Clinical and pathophysiological contribution of OCT-angiography to epiretinal membranes]. / Apports clinique et physiopathologique de l'OCT-angiographie dans les membranes épirétiniennes.

Epiretinal membranes may lead to centripetal contraction forces on the retina and its vessels. OCT-Angiography (OCT-A) is a recent tool which permits a non-invasive understanding of these vascular changes. This review focuses on the OCT-A findings in idiopathic epiretinal membranes, before and after surgery, and the role of internal limiting membrane peeling. It appears that contraction of the epiretinal membrane is associated with both a reduction in the area and perimeter of the foveal avascular zone and alterations in the superficial and deep capillary plexuses. These changes mainly reflect a vascular shift from the perifoveal to the foveal region, increasing with retinal deformation, but also probable dynamic changes in vascular flow. Membrane peeling allows at least partial improvement of these microvascular parameters. Nevertheless, some limitations of OCT-A, such as segmentation errors on a retina with highly modified architecture, can lead to a selection bias in the studies and should call for caution in the interpretation of the results. Finally, internal limiting membrane peeling contributes to changes in the retinal architecture after surgery, in particular by causing a centripetal movement of the macular capillaries and a displacement of the fovea toward the optic nerve head. This role should be clarified in future studies.

Status quo report on wastewater treatment plant, receiving water's biocoenosis and quality as basis for evaluation of large-scale ozonation process.

The project DemO3AC (demonstration of large-scale wastewater ozonation at the Aachen-Soers wastewater treatment plant, Germany) of the Eifel-Rur Waterboard contains the construction of a large-scale ozonation plant for advanced treatment of the entire 25 million m³/yr of wastewater passing through its largest wastewater treatment plant (WWTP). In dry periods, up to 70% of the receiving water consists of treated wastewater. Thus, it is expected that effects of ozonation on downstream water biocoenosis will become observable. Extensive monitoring of receiving water and the WWTP shows a severe pollution with micropollutants (already prior to WWTP inlet). (Eco-)Toxicological investigations showed increased toxicity at the inlet of the WWTP for all assays. However, endocrine-disrupting potential was also present at other sampling points at the WWTP and in the river and could not be eliminated sufficiently by the WWTP. Total cell counts at the WWTP are slightly below average. Investigations of antibiotic resistances show no increase after the WWTP outlet in the river. However, cells carrying antibiotic-resistant genes seem to be more stress resistant in general. Comparing investigations after implementation of ozonation should lead to an approximation of the correlation between micropollutants and water quality/biocoenosis and the effects that ozonation has on this matter.

Loss of end-differentiated ß-cell phenotype following pancreatic islet transplantation.

Replacement of pancreatic ß-cells through deceased donor islet transplantation is a proven therapy for preventing recurrent life-threatening hypoglycemia in type 1 diabetes. Although near-normal glucose levels and insulin independence can be maintained for many years following successful islet transplantation, restoration of normal functional ß-cell mass has remained elusive. It has recently been proposed that dedifferentiation/plasticity towards other endocrine phenotypes may play an important role in stress-induced ß-cell dysfunction in type 2 diabetes. Here we report loss of end-differentiated ß-cell phenotype in 2 intraportal islet allotransplant recipients. Despite excellent graft function and sustained insulin independence, all examined insulin-positive cells had lost expression of the end-differentiation marker, urocortin-3, or appeared to co-express the α-cell marker, glucagon. In contrast, no insulin+ /urocortin-3- cells were seen in nondiabetic deceased donor control pancreatic islets. Loss of end-differentiated phenotype may facilitate ß-cell survival during the stresses associated with islet isolation and culture, in addition to sustained hypoxia following engraftment. As further refinements in islet isolation and culture are made in parallel with exploration of alternative ß-cell sources, graft sites, and ultimately fully vascularized bioengineered insulin-secreting microtissues, differentiation status immunostaining provides a novel tool to assess whether fully mature ß-cell phenotype has been maintained.

Evaluation of reference genes for reverse transcription-quantitative PCR assays in organs of zebrafish exposed to glyphosate-based herbicide, Roundup.

Roundup is a glyphosate-based herbicide (GBH) widely used in agriculture and may cause toxic effects in non-target organisms. Model organisms, as zebrafish, and analysis of gene expression by reverse transcription-quantitative PCR (RT-qPCR) could be used to better understand the Roundup toxicity. A prerequisite for RT-qPCR is the availability of appropriate reference genes; however, they have not been described for Roundup-exposed fish. The aim of this study was to evaluate the expression stability of six reference genes (rpl8, ß-act, gapdh, b2m, ef1α, hprt1) and one expressed repetitive element (hatn10) in organs of males (brain, gill, testis) and females (ovary) of zebrafish exposed to Roundup WG at three concentrations (0.065, 0.65 and 6.5 mg N-(phosphonomethyl) glycine/l) for 7 days. Genes were ranked by geNorm, NormFinder, BestKeeper, Delta C t and RefFinder, and their best combinations were determined by geNorm and NormFinder programs. The two most stable ranked genes were specific to each organ: gill (ß-act; rpl8); brain (rpl8; ß-act); testis (ef1α; gapdh); and ovary (rpl8; hprt1). The cat transcript level was used to evaluate the effect of normalization with these reference genes. These are the first suitable reference genes described for the analysis of gene expression in organs of Roundup-exposed zebrafish, and will allow investigations of the molecular mechanisms of Roundup toxicity.

Fresnel diffractograms from pure-phase wave fields under perfect spatio-temporal coherence: Non-linear/non-local aspects and far-field behavior.

Recently, the diffractogram, that is, the Fourier transform of the intensity contrast induced by Fresnel free-space propagation of a given (exit) wave field, was investigated non-perturbatively in the phase-scaling factor S (controlling the strength of phase variation) for the special case of a Gaussian phase of width [Formula: see text]. Surprisingly, an additional low-frequency zero σ* = σ*(S, F) >0 emerges critically at small Fresnel number F (σ proportional to square of 2D spatial frequency). Here, we study the S-scaling behavior of the entire diffractogram. We identify a valley of maximum S-scaling linearity in the F - σ plane corresponding to a nearly universal physical frequency ξml = (0:143 ± 0.001)w -1/2. Large values of F (near field) are shown to imply S-scaling linearity for low σ but nowhere else (overdamped non-oscillatory). In contrast, small F values (far field) entail distinct, sizable s-bands of good S-scaling linearity (damped oscillatory). These bands also occur in simulated diffractograms induced by a complex phase map (Lena). The transition from damped oscillatory to overdamped non-oscillatory diffractograms is shown to be a critical phenomenon for the Gaussian case. We also give evidence for the occurrence of this transition in an X-ray imaging experiment. Finally, we show that the extreme far-field limit generates a σ-universal diffractogram under certain requirements on the phase map: information on phase shape then is solely encoded in S-scaling behavior.

The impact of genetic variants on BMI increase during childhood versus adulthood.

BACKGROUND: Genetic variants that predispose individuals to obesity may have differing influences during childhood versus adulthood, and additive effects of such variants are likely to occur. Our ongoing studies to identify genetic determinants of obesity in American Indians have identified 67 single-nucleotide polymorphisms (SNPs) that reproducibly associate with maximum lifetime non-diabetic body mass index (BMI). This study aimed to identify when, during the lifetime, these variants have their greatest impact on BMI increase. SUBJECTS/METHODS: A total of 5906 Native Americans of predominantly Pima Indian heritage with repeated measures of BMI between the ages of 5 and 45 years were included in this study. The association between each SNP with the rates of BMI increase during childhood (5-19 years) and adulthood (20-45 years) were assessed separately. The significant SNPs were used to calculate a cumulative allelic risk score (ARS) for childhood and adulthood, respectively, to assess the additive effect of these variants within each period of life. RESULTS: The majority of these SNPs (36 of 67) were associated with rate of BMI increase during childhood (P-value range: 0.00004-0.05), whereas only nine SNPs were associated with rate of BMI change during adulthood (P-value range: 0.002-0.02). These 36 SNPs associated with childhood BMI gain likely had a cumulative effect as a higher childhood-ARS associated with rate of BMI change (ß=0.032 kg m(-2) per year per risk allele, 95% confidence interval: 0.027-0.036, P<0.0001), such that at age 19 years, individuals with the highest number of risk alleles had a BMI of 10.2 kg m(-2) greater than subjects with the lowest number of risk alleles. CONCLUSIONS: Overall, our data indicates that genetic polymorphisms associated with lifetime BMI may influence the rate of BMI increase during different periods in the life course. The majority of these polymorphisms have a larger impact on BMI during childhood, providing further evidence that prevention of obesity will need to begin early in life.

[Allergies and adverse events associated with fluoroquinolones]. / Allergies et effets indésirabtes dus aux fluoroquinolones.

The prescription ot fluoroquinolones has been constantly increasing over the past decade. consequently, an increasing number of hyper-sensitivity reactions and adverse events have been reported. The aim of the review is to discuss the incidence of hypersensitivity reactions either IgE (immediate) or T cells mediated (delayed). We will make an overview ofthe diagnostic tools available to detect such hypersensitivity reactions. Finally, the specific adverse events associated with fluoroquinolones, including tendinopathy, chondrotoxicity, peripheral neuropathy or retinal detachment will be discussed.

[Cell transplantation: current treatments and future prospects]. / Transplantation cellulaire: traitements actuels et perspectives d'avenir.

Regenerative medicine aims to replace a body function or specific cell loss. It includes therapies at the forefront of modem medicine, issuing from translational biomedical research. Transplantation of organs and cells has revolutionized the management of patients for whom medical treatment is a failure. Unfortunately, organ shortage is limiting treatment possibility. As an example, among the 15,000 patients with type I diabetes in Switzerland, only approximately 30 can receive a pancreas or an islet transplant per year. Second example, 500 patients die each year in Switzerland from alcoholic cirrhosis because no treatment is available. Transplantation of islet cells, hepatocytes, mesenchymal stem cells or dopaminergic neurons represents hope fora therapy available for large populations of patients.

Brain-derived neurotrophic factor in human subjects with function-altering melanocortin-4 receptor variants.

BACKGROUND: In rodents, hypothalamic brain-derived neurotrophic factor (BDNF) expression appears to be regulated by melanocortin-4 receptor (MC4R) activity. The impact of MC4R genetic variation on circulating BDNF in humans is unknown. OBJECTIVE: The objective of this study is to compare BDNF concentrations of subjects with loss-of-function (LOF) and gain-of-function (GOF) MC4R variants with those of controls with common sequence MC4R. METHODS: Circulating BDNF was measured in two cohorts with known MC4R sequence: 148 subjects of Pima Indian heritage ((mean±s.d.): age, 15.7±6.5 years; body mass index z-scores (BMI-Z), 1.63±1.03) and 69 subjects of Hispanic heritage (10.8±3.6 years; BMI-Z, 1.57±1.07). MC4R variants were characterized in vitro by cell surface expression, receptor binding and cyclic AMP response after agonist administration. BDNF single-nucleotide polymorphisms (SNPs) rs12291186, rs6265 and rs7124442 were also genotyped. RESULTS: In the Pima cohort, no significant differences in serum BDNF was observed for 43 LOF subjects versus 65 LOF-matched controls (age, sex and BMI matched; P=0.29) or 20 GOF subjects versus 20 GOF-matched controls (P=0.40). Serum BDNF was significantly associated with genotype for BDNF rs12291186 (P=0.006) and rs6265 (P=0.009), but not rs7124442 (P=0.99); BDNF SNPs did not interact with MC4R status to predict serum BDNF. In the Hispanic cohort, plasma BDNF was not significantly different among 21 LOF subjects, 20 GOF subjects and 28 controls (P=0.79); plasma BDNF was not predicted by BDNF genotype or BDNF-x-MC4R genotype interaction. CONCLUSIONS: Circulating BDNF concentrations were not significantly associated with MC4R functional status, suggesting that peripheral BDNF does not directly reflect hypothalamic BDNF secretion and/or that MC4R signaling is not a significant regulator of the bulk of BDNF expression in humans.

Transplanted human pancreatic islets after long-term insulin independence.

Long-term insulin independence after islets of Langerhans transplantation is rarely achieved. The aims of this study were to identify the histological and immunological features of islets transplanted in a type 1 diabetic patient who died of a cerebral hemorrhage after >13 years insulin independence. Islets were pooled from two donors with respectively one and five HLA mismatches. Insulin-positive islets were found throughout the right and left liver, and absent in the pancreas. Two- and three-dimensional analysis showed that islets lost their initial rounded and compact morphology, had a mean diameter of 136 µm and were constituted of an unfolded epithelial band of 39.1 µm. Leukocyte phenotyping showed no evidence of a tolerogenic environment in the islet-containing portal spaces. Finally, HLA typing of microdissected islets showed HLA from the best matched donor in all 23 microdissection samples, compared to 1/23 for the least matched donor. This case report demonstrates that allogeneic islets can survive over 13 years while maintaining insulin independence. Allogeneic islets had unique morphologic features and implanted in the liver regardless of their size. Finally, our results suggest that, in this case, rejection had been prevalent over autoimmunity, although this hypothesis warrants further investigation.

HLA-DRB1 reduces the risk of type 2 diabetes mellitus by increased insulin secretion.

AIMS/HYPOTHESIS: We sought to identify the physiological implications of genetic variation at the HLA-DRB1 region in full-heritage Pima Indians in Arizona. METHODS: Single-nucleotide polymorphisms from the HLA region on chromosome 6p were tested for association with skeletal muscle mRNA expression of HLA-DRB1 and HLA-DRA, and with type 2 diabetes mellitus and prediabetic traits. RESULTS: The A allele at rs9268852, which tags HLA-DRB1 02(1602), was associated both with higher HLA-DRB1 mRNA expression (n = 133, p = 4.27 × 10(-14)) and decreased risk of type 2 diabetes (n = 3,265, OR 0.723, p = 0.002). Among persons with normal glucose tolerance (n = 266) this allele was associated with a higher mean acute insulin response during an intravenous glucose tolerance test (p = 0.005), higher mean 30 min insulin concentration during an oral glucose tolerance test (p = 0.017) and higher body fat percentage (p = 0.010). The polymorphism was not associated with HLA-DRA mRNA expression or insulin sensitivity. CONCLUSIONS/INTERPRETATION: HLA-DRB1*02 is protective for type 2 diabetes, probably by enhancing self tolerance, thereby protecting against the autoimmune-mediated reduction of insulin secretion.

Variants in ACAD10 are associated with type 2 diabetes, insulin resistance and lipid oxidation in Pima Indians.

AIMS/HYPOTHESIS: A prior genome-wide association study in Pima Indians identified a variant within the ACAD10 gene that is associated with early-onset type 2 diabetes. Acylcoenzyme A dehydrogenase 10 (ACAD10) catalyses mitochondrial fatty acid beta-oxidation, which plays a pivotal role in developing insulin resistance and type 2 diabetes. Therefore, ACAD10 was analysed as a positional and biological candidate for type 2 diabetes. METHODS: Twenty-three SNPs were genotyped in 1,500 Pima Indians to determine the linkage disequilibrium pattern across ACAD10. Association with type 2 diabetes was determined by genotyping four tag single nucleotide polymorphisms (SNPs) in a population-based sample of 3,501 full-heritage Pima Indians; two associated SNPs were further genotyped in a second population-based sample of 3,723 American Indians. Associations with quantitative traits were assessed in 415 non-diabetic full heritage Pima individuals who had been metabolically phenotyped. RESULTS: SNPs rs601663 and rs659964 were associated with type 2 diabetes in the full-heritage Pima Indian sample (p=0.04 and 0.0006, respectively), and rs659964 was further associated with type 2 diabetes in the second American Indian sample (p=0.04). Combination of these two samples provided the strongest evidence for association (p=0.009 and 0.00007, for rs601663 and rs659964, respectively). Quantitative trait analyses identified nominal associations with both lower lipid oxidation rate and larger subcutaneous abdominal adipocyte size, which is consistent with the known physiology of ACAD10, and also identified associations with increased insulin resistance. CONCLUSIONS/INTERPRETATION: We propose that ACAD10 variation may increase type 2 diabetes susceptibility by impairing insulin sensitivity via abnormal lipid oxidation.

The VEP1 gene (At4g24220) encodes a short-chain dehydrogenase/reductase with 3-oxo-Delta4,5-steroid 5beta-reductase activity in Arabidopsis thaliana L.

The Arabidopsis thaliana VEP1 gene product shows about 70% sequence identity to Digitalis lanata progesterone 5beta-reductase, an enzyme considered to catalyze a key step in the biosynthesis of cardiac glycosides. A. thaliana does not accumulate cardenolides but protein extracts prepared from its leaves were capable of reducing progesterone to 5beta-pregnane-3,20-dione. A full-length cDNA clone encoding a Delta(4,5)-steroid 5beta-reductase (At5beta-StR, EC 1.1.1.145/1.3.1.23), a member of the short-chain dehydrogenase/reductase (SDR) family, was isolated from A. thaliana leaves. A SphI/SalI At5beta-StR gene fragment was cloned into the pQE vector system and transformed into Escherichia coli. The gene was functionally expressed and the recombinant His-tagged fusion protein was characterized. K(m) values and specific activities for putative 3-oxo-Delta(4,5)-steroid substrates such as progesterone, cortisol, cortexone and 4-androstene-3,17-dione, and for the co-substrate NADPH were determined. Progesterone was stereo-specifically reduced to 5beta-pregnane-3,20-dione and none of the 3-oxo-Delta(5,6)-steroids tested were accepted as a substrate. The gene encoding At5beta-StR was strongly transcribed in stems and leaves. A three-dimensional model of At5beta-StR highlights a close structural similarity to the related, previously described D. lanata progesterone 5beta-reductase. This homology extends to the active site where single amino acid substitutions might be responsible for the increased catalytic efficiency of At5beta-StR when compared to the activity of the recombinant form of the D. lanata enzyme.

The Gly482Ser genotype at the PPARGC1A gene and elevated blood pressure: a meta-analysis involving 13,949 individuals.

The protein encoded by the PPARGC1A gene is expressed at high levels in metabolically active tissues and is involved in the control of oxidative stress via reactive oxygen species detoxification. Several recent reports suggest that the PPARGC1A Gly482Ser (rs8192678) missense polymorphism may relate inversely with blood pressure. We used conventional meta-analysis methods to assess the association between Gly482Ser and systolic (SBP) or diastolic blood pressures (DBP) or hypertension in 13,949 individuals from 17 studies, of which 6,042 were previously unpublished observations. The studies comprised cohorts of white European, Asian, and American Indian adults, and adolescents from South America. Stratified analyses were conducted to control for population stratification. Pooled genotype frequencies were 0.47 (Gly482Gly), 0.42 (Gly482Ser), and 0.11 (Ser482Ser). We found no evidence of association between Gly482Ser and SBP [Gly482Gly: mean = 131.0 mmHg, 95% confidence interval (CI) = 130.5-131.5 mmHg; Gly482Ser mean = 133.1 mmHg, 95% CI = 132.6-133.6 mmHg; Ser482Ser: mean = 133.5 mmHg, 95% CI = 132.5-134.5 mmHg; P = 0.409] or DBP (Gly482Gly: mean = 80.3 mmHg, 95% CI = 80.0-80.6 mmHg; Gly482Ser mean = 81.5 mmHg, 95% CI = 81.2-81.8 mmHg; Ser482Ser: mean = 82.1 mmHg, 95% CI = 81.5-82.7 mmHg; P = 0.651). Contrary to previous reports, we did not observe significant effect modification by sex (SBP, P = 0.966; DBP, P = 0.715). We were also unable to confirm the previously reported association between the Ser482 allele and hypertension [odds ratio: 0.97, 95% CI = 0.87-1.08, P = 0.585]. These results were materially unchanged when analyses were focused on whites only. However, statistical evidence of gene-age interaction was apparent for DBP [Gly482Gly: 73.5 (72.8, 74.2), Gly482Ser: 77.0 (76.2, 77.8), Ser482Ser: 79.1 (77.4, 80.9), P = 4.20 x 10(-12)] and SBP [Gly482Gly: 121.4 (120.4, 122.5), Gly482Ser: 125.9 (124.6, 127.1), Ser482Ser: 129.2 (126.5, 131.9), P = 7.20 x 10(-12)] in individuals <50 yr (n = 2,511); these genetic effects were absent in those older than 50 yr (n = 5,088) (SBP, P = 0.41; DBP, P = 0.51). Our findings suggest that the PPARGC1A Ser482 allele may be associated with higher blood pressure, but this is only apparent in younger adults.

Electron-beam-induced topographical, chemical, and structural patterning of amorphous titanium oxide films.

Electrolytically deposited amorphous TiO2 films on steel are remarkably sensitive to electron beam (e-beam) irradiation at moderate energies at 20 keV, resulting in controlled local oxide reduction and crystallization, opening the possibility for local topographical, chemical, and structural modifications within a biocompatible, amorphous, and semiconducting matrix. The sensitivity is shown to vary significantly with the annealing temperature of as-deposited films. Well-defined irradiation conditions in terms of probe current IP (5 microA) and beam size were achieved with an electron probe microanalyzer. As shown by atomic force and optical microscopy, micro-Raman spectroscopy, wavelength-dispersive X-ray (WDX), and Auger analyses, e-beam exposure below 1 Acm-2 immediately leads to electron-stimulated oxygen desorption, resulting in a well-defined volume loss primarily limited to the irradiated zone under the electron probe and in a blue color shift in this zone because of the presence of Ti2O3. Irradiation at 5 Acm(-2) (IP = 5 microA) results in local crystallization into anatase phase within 1 s of exposure and in reduction to TiO after an extended exposure of 60 s. Further reduction to the metallic state could be observed after 60 s of exposure at approximately 160 Acm(-2). The local reduction could be qualitatively sensed with WDX analysis and Auger line scans. An estimation of the film temperature in the beam center indicates that crystallization occurs at less than 150 degrees C, well below the atmospheric crystallization temperature of the present films. The high e-beam sensitivity in combination with the well-defined volume loss from oxygen desorption allows for precise electron lithographic topographical patterning of the present oxides. Irradiation effects leading to the observed reduction and crystallization phenomena under moderate electron energies are discussed.

Design and analysis of genetic association studies to finely map a locus identified by linkage analysis: sample size and power calculations.

Association (e.g. case-control) studies are often used to finely map loci identified by linkage analysis. We investigated the influence of various parameters on power and sample size requirements for such a study. Calculations were performed for various values of a high-risk functional allele (fA), frequency of a marker allele associated with the high risk allele (f1), degree of linkage disquilibrium between functional and marker alleles (D') and trait heritability attributable to the functional locus (h2). The calculations show that if cases and controls are selected from equal but opposite extreme quantiles of a quantitative trait, the primary determinants of power are h2 and the specific quantiles selected. For a dichotomous trait, power also depends on population prevalence. Power is optimal if functional alleles are studied (fA= f1 and D'= 1.0) and can decrease substantially as D' diverges from 1.0 or as f(1) diverges from fA. These analyses suggest that association studies to finely map loci are most powerful if potential functional polymorphisms are identified a priori or if markers are typed to maximize haplotypic diversity. In the absence of such information, expected minimum power at a given location for a given sample size can be calculated by specifying a range of potential frequencies for fA (e.g. 0.1-0.9) and determining power for all markers within the region with specification of the expected D' between the markers and the functional locus. This method is illustrated for a fine-mapping project with 662 single nucleotide polymorphisms in 24 Mb. Regions differed by marker density and allele frequencies. Thus, in some, power was near its theoretical maximum and little additional information is expected from additional markers, while in others, additional markers appear to be necessary. These methods may be useful in the analysis and interpretation of fine-mapping studies.

Distribution of microglial cells in the cerebral hemispheres of embryonic and neonatal chicks.

The distribution, morphology and morphometry of microglial cells in the chick cerebral hemispheres from embryonic day 4 (E4) to the first neonatal day (P1) were studied by histochemical labeling with a tomato (Lycopersicon esculentum) lectin. The histochemical analysis revealed lectin-reactive cells in the nervous parenchyma on day E4. Between E4 (5.7 +/- 1.35 mm length) and E17 (8.25 +/- 1.2 mm length), the lectin-reactive cells were identified as ameboid microglia and observed starting from the subventricular layer, distributed throughout the mantle layer and in the proximity of the blood vessels. After day E13, the lectin-reactive cells exhibited elongated forms with small branched processes, and were considered primitive ramified microglia. Later, between E18 (5.85 +/- 1.5 mm cell body length) and P1 (3.25 +/- 0.6 mm cell body length), cells with more elongated branched processes were observed, constituting the ramified microglia. Our findings provide additional information on the migration and differentiation of microglial cells, whose ramified form is observed at the end of embryonic development. The present paper focused on the arrangement of microglial cells in developing cerebral hemispheres of embryonic and neonatal chicks, which are little studied in the literature. Details of morphology, morphometry and spatial distribution of microglial cells contributed to the understanding of bird and mammal central nervous system ontogeny. Furthermore, the identification and localization of microglial cells during the normal development could be used as a morphological guide for embryonic brain injury researches.

Distribution of microglial cells in the cerebral hemispheres of embryonic and neonatal chicks

The distribution, morphology and morphometry of microglial cells in the chick cerebral hemispheres from embryonic day 4 (E4) to the first neonatal day (P1) were studied by histochemical labeling with a tomato (Lycopersicon esculentum) lectin. The histochemical analysis revealed lectin-reactive cells in the nervous parenchyma on day E4. Between E4 (5.7 ± 1.35 mm length) and E17 (8.25 ± 1.2 mm length), the lectin-reactive cells were identified as ameboid microglia and observed starting from the subventricular layer, distributed throughout the mantle layer and in the proximity of the blood vessels. After day E13, the lectin-reactive cells exhibited elongated forms with small branched processes, and were considered primitive ramified microglia. Later, between E18 (5.85 ± 1.5 mm cell body length) and P1 (3.25 ± 0.6 mm cell body length), cells with more elongated branched processes were observed, constituting the ramified microglia. Our findings provide additional information on the migration and differentiation of microglial cells, whose ramified form is observed at the end of embryonic development. The present paper focused on the arrangement of microglial cells in developing cerebral hemispheres of embryonic and neonatal chicks, which are little studied in the literature. Details of morphology, morphometry and spatial distribution of microglial cells contributed to the understanding of bird and mammal central nervous system ontogeny. Furthermore, the identification and localization of microglial cells during the normal development could be used as a morphological guide for embryonic brain injury researches.