variable diameter
Dotaz
Zobrazit nápovědu
Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the ecophysiological implications of variation in lumen diameter together with a summary of our current understanding of vessel development and its endogenous regulation. We analyzed inter-specific variation of the mean hydraulic vessel diameter (Dv ) across biomes, intra-specific variation of Dv under natural and controlled conditions, and intra-plant variation. We found that the Dv measured in young branches tends to stay below 30 µm in regions experiencing winter frost, whereas it is highly variable in the tropical rainforest. Within a plant, the widest vessels are often found in the trunk and in large roots; smaller diameters have been reported for leaves and small lateral roots. Dv varies in response to environmental factors and is not only a function of plant size. Despite the wealth of data on vessel diameter variation, the regulation of diameter is poorly understood. Polar auxin transport through the vascular cambium is a key regulator linking foliar and xylem development. Limited evidence suggests that auxin transport is also a determinant of vessel diameter. The role of auxin in cell expansion and in establishing longitudinal continuity during secondary growth deserve further study.
Background Left atrial (LA) enlargement is a predictor of worse outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence between single LA diameter (LAd) and LA volume (LAV) in patients undergoing catheter ablation for AF. Methods Total 782 patients (aged 58±11 yrs; 70% males; 56% paroxysmal AF) were enroled in 2 centres in the period of 2007–2011. Echocardiographic antero-posterior LAd was assessed in parasternal long-axis view and LAV was derived from electroanatomic 3 D reconstruction of LA (183±50 CARTO mapping points; 55% CT image registration). Results Mean LAd was 45±6 mm (median: 45; IQR: 41–49; range: 25–73 mm) and mean LAV was 134±42 ml (median: 128; IQR: 103–160; range: 46–313 ml). Correlation between both variables was weak (r=0.56; p <0.0001) and area under the ROC curve for the LAd-based prediction of LAV >130 was 0.76. Accordingly, severe dilation of LA (LAV >160 ml; upper quartile) was found only in 56% of patients with LAd >50 mm while it appeared in 11% of those with LAd<45 mm. In multivariate regression analysis, age, gender, and type of AF were independent covariates of LAV yielding the equation of LAV (ml)=68+0.41.cube LAd (cc)+15 (if male)+0.48.age (yrs) – 21 (if paroxysmal AF). Substantial between-centre bias was also found reflecting subjective nature of echocardiographic readings. Adjustment for all covariates improved the correspondence between LAd-predicted and true LAV only modestly (AUC increased from 0.76 to 0.83) with wide 95% limits of agreement (−58 to +60 ml). Conclusions Considerable disagreement between echocardiographic LAd and 3D mapping LAV was observed in patients with non-valvular atrial fibrillation. Single LA dimension should not be considered relevant criterion for the indication of rhythm/rate control therapy and, particularly, for the selection of suitable candidates for catheter ablation.
- Klíčová slova
- elektroanatomické mapování, rozměr levé síně,
- MeSH
- echokardiografie * metody využití MeSH
- fibrilace síní * diagnóza terapie MeSH
- katetrizační ablace * metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mapování potenciálů tělesného povrchu * metody MeSH
- prediktivní hodnota testů MeSH
- senioři MeSH
- srdce - funkce levé síně * MeSH
- srdeční síně * anatomie a histologie MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
Mean diameter of nucleolar bodies (nucleoli without the perinucleolar chromatin) per cell was studied in human leukemic myeloblasts represented by K 562 and Kasumi 1 cell lines which originated from chronic and acute myeloid leukaemia. The measurement of mean diameter of nucleolar bodies in specimens stained for RNA was very simple. Such approach eliminated the variability of the perinucleolar chromatin discontinuous shell which might influence the measured nucleolar size as suggested by earlier studies. Ageing of K 562 myeloblasts produced a significant decrease of cells in S+G2 phase of the cell cycle accompanied by a significant reduction of mean diameter of nucleolar bodies (MDNoBs) per cell. In contrast, treatment of Kasumi 1 myeloblasts with histone deacetylase inhibitor - Trichostatin A - produced a large incidence of resistant cells in S+G2 phase which were characterised by a large increase of MDNoBs. Thus, MDNoBs in leukemic myeloblasts might be a helpful tool to estimate the incidence of cells in the S+G2 phase at the single cell level in smear preparations when the number of cells is very small.
- MeSH
- akutní erytroblastická leukemie genetika patologie MeSH
- antigeny jaderné MeSH
- buněčné jadérko genetika patologie MeSH
- buňky K562 MeSH
- chronická myeloidní leukemie genetika patologie MeSH
- financování organizované MeSH
- G2 fáze fyziologie MeSH
- jaderné proteiny MeSH
- lidé MeSH
- organizátor jadérka patologie MeSH
- počet buněk MeSH
- prekurzorové buňky granulocytů patologie MeSH
- proliferace buněk MeSH
- RNA nádorová analýza MeSH
- S fáze fyziologie MeSH
- Check Tag
- lidé MeSH
PURPOSE: To compare the thickness of the retinal nerve fibre layer (RNFL) in hydrophthalmic glaucomatous eyes in children with age-matched healthy controls using scanning laser polarimetry with variable corneal compensation (GDxVCC). METHODS: Twenty hydrophthalmic eyes of 20 patients with the mean age of 10.64 ± 3.02 years being treated for congenital or infantile glaucoma were included in the analysis. Evaluation of RNFL thickness measured by GDxVCC in standard Temporal-Superior-Nasal-Inferior-Temporal (TSNIT) parameters was performed. The results were compared to TSNIT values of an age-matched control group of 120 healthy children published recently as referential values. The correlation between horizontal corneal diameter and RNFL thickness in hydrophthalmic eyes was also investigated. RESULTS: The mean ± SD values in TSNIT Average, Superior Average, Inferior Average and TSNIT SD in hydrophthalmic eyes were 52.3 ± 11.4, 59.7 ± 17.1, 62.0 ± 15.6 and 20.0 ± 7.8 μm, respectively. All these values were significantly lower compared to referential TSNIT parameters of age-matched healthy eyes (p = 0.021, p = 0.001, p = 0.003 and p = 0.018, respectively). A substantial number of hydrophthalmic eyes laid below the level of 5% probability of normality in respective TSNIT parameters: 30% of the eyes in TSNIT average, 50% of the eyes in superior average, 30% of the eyes in inferior average and 45% of the eyes in TSNIT SD. No significant correlation between enlarged corneal diameter and RNFL thickness was found. CONCLUSIONS: The mean values of all standard TSNIT parameters assessed using GDxVCC in hydrophthalmic glaucomatous eyes in children were significantly lower in comparison with referential values of healthy age-matched children.
- MeSH
- dítě MeSH
- dvojitý lom MeSH
- hydroftalmus patologie MeSH
- lidé MeSH
- mladiství MeSH
- nemoci zrakového nervu patologie MeSH
- nervová vlákna patologie MeSH
- nitrooční tlak MeSH
- průřezové studie MeSH
- retinální gangliové buňky patologie MeSH
- rohovka patologie MeSH
- skenovací laserová polarimetrie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
AIMS: In somatotroph pituitary neuroendocrine tumours (adenomas), a pattern of cytokeratin (CK) 18 expression is used for tumour subclassification, with possible clinical implications. Rare somatotroph tumours do not express CK 18. We aimed to characterise this subset clinically and histologically. METHODS AND RESULTS: Clinical and pathological data for the study were derived from a previously published data set of a cohort of 110 patients with acromegaly. Data included serum levels of insulin-like growth factor 1 (IGF1), growth hormone (GH), prolactin and thyroid-stimulating hormone (TSH), tumour diameter, tumour invasion defined by Knosp grade and immunohistochemical data concerning the expression of Ki67, p53, E-cadherin, somatostatin receptor (SSTR)1, SSTR2A, SSTR3, SSTR5 and D2 dopamine receptor. Additional immunohistochemical analysis (AE1/3, CK 8/18, vimentin, neurofilament light chain, internexin-α) was performed. CK 18 was negative in 10 of 110 (9.1%) tumours. One of these tumours was immunoreactive with CK 8/18 antibody, while the remainder expressed only internexin-α intermediate filament in patterns similar to CK 18 (perinuclear fibrous bodies). CK-negative tumours showed no significant differences with respect to biochemical, radiological or pathological features. They showed significantly higher expression of SSTR2A compared to the sparsely granulated subtype and significantly lower expression of E-cadherin compared to the non-sparsely granulated subtypes of tumours. The tumours showed divergent morphology and hormonal expression: two corresponded to densely granulated tumours and three showed co-expression of prolactin and morphology of either mammosomatotroph or somatotroph-lactotroph tumours. Four tumours showed morphology and immunoprofile compatible with plurihormonal Pit1-positive tumours. CONCLUSIONS: CK-negative somatotroph tumours do not represent a distinct subtype of somatotroph tumours, and can be further subdivided according to their morphology and immunoprofile.
OBJECTIVE: To compare capillary diameters, density and reactivity in high-risk pregnancies complicated by pregnancy-induced hypertension (PIH) to other high-risk pregnancies not affecting microcirculation (O). METHODS: Patients hospitalized at a tertiary referral center from January to May 2012 were enrolled in the prospective pilot study. Five microscopic fields were recorded from the nailfold for capillary diameters and functional capillary density assessment. One microscopic field was assessed before and after venous congestion to evaluate the change in capillary diameters. The results were expressed as median (interquartile range). Wilcoxon rank-sum test was used for the analysis of statistical significance (level of significance was set to p < 0.05). RESULTS: In total, 31 patients were available for statistical analysis (PIH = 17;O = 14). Patients in the PIH group had significantly longer capillaries (123(91;182) vs. 72(65;107)μm, p = 0.003) and higher average capillary diameter (12(10;13) vs. 10(9;11)μm, p = 0.017). The difference in mean functional capillary density was not significant (20(17;25) vs. 19(15:21), p > 0.05), however, significantly reduced capillary recruitment (1(0;7) vs. 10(6;17), p = 0.006) was found in PIH. Preeclampsia was observed in 10 patients from the PIH group. These patients did not significantly differ from the rest of the PIH group in the abovementioned variables. CONCLUSION: This is the first pilot study concerning change of capillary diameters after venous congestion in pregnancy. The reduced capillary recruitment and reduced capability of further dilation of capillaries after venous congestion observed in women with PIH may suggest a significantly reduced functional capacity of the microcirculation and increased load on capillary endothelium in pregnancy complicated by gestational hypertension.
- MeSH
- dospělí MeSH
- hospitalizace MeSH
- hypertenze indukovaná těhotenstvím patofyziologie MeSH
- kapiláry patofyziologie MeSH
- lidé MeSH
- mikrocirkulace fyziologie MeSH
- pilotní projekty MeSH
- prospektivní studie MeSH
- rizikové těhotenství * MeSH
- těhotenství MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Thoracic aortic aneurysm and dissection (TAAD) is a major cause of cardiovascular morbidity and mortality. Loss-of-function variants in LOX, encoding the extracellular matrix crosslinking enzyme lysyl oxidase, have been reported to cause familial TAAD. Using a next-generation TAAD gene panel, we identified five additional probands carrying LOX variants, including two missense variants affecting highly conserved amino acids in the LOX catalytic domain and three truncating variants. Connective tissue manifestations are apparent in a substantial fraction of the variant carriers. Some LOX variant carriers presented with TAAD early in life, while others had normal aortic diameters at an advanced age. Finally, we identified the first patient with spontaneous coronary artery dissection carrying a LOX variant. In conclusion, our data demonstrate that loss-of-function LOX variants cause a spectrum of aortic and arterial aneurysmal disease, often combined with connective tissue findings.
- MeSH
- aneurysma hrudní aorty genetika patofyziologie MeSH
- aorta metabolismus MeSH
- arterie metabolismus MeSH
- disekce aorty genetika patofyziologie MeSH
- dospělí MeSH
- genetická predispozice k nemoci genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- lysyloxidasa genetika metabolismus MeSH
- mutace genetika MeSH
- nemoci pojiva genetika MeSH
- pojivová tkáň metabolismus MeSH
- rodokmen MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
v sestavě 102 renálních onkocytomů vybraných ze souboru 2500 epiteliálních nádorů ledvin byl proveden rozbor zaměřený na velikost, multifokalitu, makroskopický vzhled a histologickou stavbu. Velikost nádorů se pohybovala od 1,5 do 13 cm v největším rozměru, průměr 6,3 cm. Tři případy renálního onkocytomů byly multifokální, 4 byly kombinovány s jiným primárním nádorem ledviny (Ikrát angiomyolipom, Ikrát konvenční renální karcinom, 2krát papilámí renální karcinom). Centrální fibróza či jizva byla přítomná u 13 případů. Větší ložisko hemoragie bylo zachyceno u 11 tumorů, ve 4 případech byla zaznamenána rozsáhlá nekróza. Histologický bylo 70 případů solidně alveolámího irůstu. Tubulámí typ růstu byl zaznamenán u 31 nádorů. V 1 tumoru byl přítomen neobvyklý typ tubopapilámího („glomeruloidního") růstu. Ložiska atypických jader byla zjištěna v 58 případech. Ve 4 onkocytomech byla nalezena větší ložiska světlobuněčné přeměny onkocytů. Psamomatózní tělíska byla prokázána u 9 nádorů a u 4 onkocytomů byla zaznamenána ložiska metaplastické kosti. Ve dvou nádorech byla přítomná hyalinní intracytoplazmatická a extracelulární tělíska. Renální onkocytom má široké morfologické spektrum a diagnóza by měla být založena na rozboru architektonických a cytologických vlastností nádoru. Diskutujeme diferenciální diagnostiku s různými nádory ledvin s granulami cytoplazmou. Mezi tyto nádory patří konvenční renální karcinom, chromofobocelulámí karcinom a vzácné případy papilámího renálního karcinomu.
From the collection of 2500 cases of renal epithelial tumors in our files, 102 renal oncocytomas were analyzed for size, multifocality and a morphologic spectrum of the growth pattern. The size of the tumors ranged from 1.5 to 13 cm in diameter, with a mean of 6.3 cm. Three cases were multifocal, four cases were combined with another primary renal tumor (Ix angiomyolipoma, Ix conventional renal carcinoma, 2x papillary renal ceU carcinoma). A central fibrosis or a scar was noted in 13 cases, and there was a gross area of hemorrhage in 11 cases. In 4 cases extensive necroses were recognized. Histologically, an alveolar pattern was noted in 70 cases. A tubular pattern was revealed in 31 cases and an unusual tubopapillar („glomeridoid") pattern was noted in one case. Foci of atypical nuclei were identified in 58 cases. In 4 oncocytomas broad areas of clearance of the oncocytes were found. Psammoma bodies were recognized in 9 tumors and foci of ossification were present m 4 cases. Intracellular and extracellular hyaline globides were noted in two cases. Renal oncocytoma has a variable morphologic spectmm, and its diagnosis should be based on an analysis of structural and cytologic features. Differential diagnosis of renal oncocytomas with various tumors of the kidney which contain granvdar cytoplasm is discussed. These tumors with granular cytoplasm include conventional renal cell carcinomas, chromophobe cell carcinomas, and rare examples of papillary renal carcinomas.
- MeSH
- diagnostické techniky urologické metody MeSH
- diferenciální diagnóza metody MeSH
- dospělí MeSH
- histologie MeSH
- karcinom z renálních buněk diagnóza patologie MeSH
- lidé MeSH
- nádory glandulární a epitelové diagnóza patologie MeSH
- nádory ledvin diagnóza patologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
Cranial bone thickness varies among modern humans, and many factors influencing this variability remain unclear. Growth hormones and physical activity are thought to influence the vault thickness. Considering that both systemic factors and energy supply influence the vascular system, and taking into account the structural and biomechanical interaction between endocranial vessels and vault bones, in this study we evaluate the correlation between vascular and bone diameters. In particular, we tested the relationship between the thickness of the parietal bone (which is characterized, in modern humans, by a complex vascular network) and the lumen size of the middle meningeal and diploic vessels, in adult modern humans. Our results show no patent correlation between the thickness of parietal bone and the size of the main vascular channels. Values and distributions of the branching patterns, as well as anatomical relationships between vessels and bones, are also described in order to provide information concerning the arrangement of the endocranial vascular morphology. This information is relevant in both evolutionary and medical contexts. Anat Rec, 299:888-896, 2016. © 2016 Wiley Periodicals, Inc.
- MeSH
- arteriae cerebrales anatomie a histologie fyziologie MeSH
- biologická evoluce MeSH
- dospělí MeSH
- lebka anatomie a histologie fyziologie MeSH
- lidé MeSH
- temenní kost anatomie a histologie fyziologie MeSH
- zkameněliny * MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Selected biosorbents, brewers draff and grape waste, have been encapsulated in calcium alginate beads and used for the removal of Cr(VI) from aqueous solutions. The effects of encapsulation variables, including the type of waste, the percentage of waste in the beads and the curing time of the beads in CaCl2, on the diameters of the beads and Cr(VI) sorption kinetics have been evaluated. In total, 21 different types of beads were produced. The diameters of the beads increased with increasing amounts of encapsulated biomaterial. Beads that contained grape waste were larger than those containing brewers draff. The most efficient beads for Cr(VI) removal were beads that contained 4% (w/w) of grape waste. No significant differences in the kinetics of Cr(VI) sorption were found with respect to the curing time variable in the case of grape waste calcium alginate beads. Statistical analysis confirmed that the type and percentage of waste are the critical parameters influencing the diameters of the beads and Cr(VI) removal. It was proven that the sorption efficiencies of the beads containing draff and grape waste encapsulated under the optimum conditions were much higher than the efficiencies obtained when using both wastes in their native states.
- MeSH
- adsorpce MeSH
- algináty chemie MeSH
- chrom chemie izolace a purifikace MeSH
- kinetika MeSH
- kyselina glukuronová chemie MeSH
- kyseliny hexuronové chemie MeSH
- látky znečišťující životní prostředí chemie izolace a purifikace MeSH
- odpadní produkty MeSH
- roztoky MeSH
- tobolky MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
