Why Plagiotheciumsylvaticum (Brid.) Schimp. (Plagiothecium, Plagiotheciaceae) has priority over P.platyphyllum Mönk.?

Re-assessment of the lectotype of Hypnumsylvaticum Brid. (≡ Plagiotheciumsylvaticum (Brid.) Schimp.) (B 31 0915 01) showed that this specimen is characterised by dense, 6-10 cm long stems, pale green, yellowish-green to dark green and dull foliage; with complanate, ovate, not imbricate and not julaceous, 2.0-3.0 × 1.0-1.6 mm leaves; acute and denticulate, often eroded apices; 75.0-160.0 × 12.5-20.0 µm laminal cells at mid-leaf, which form diagonal rows, and decurrencies of 3-4 rows of rectangular to square, inflated cells, forming distinct auricules. Thus, this specimen represents the characteristics of the taxon currently referred to as Plagiotheciumplatyphyllum Mönk. Taking into account the above and the fact that the name H.sylvaticum was published first, the correct name for the species is Plagiotheciumsylvaticum. Whereas the later one (P.platyphyllum) is a synonym. Additionally, in this article for the name P.platyphyllum, a lectotype is designated and a new synonym (Plagiotheciumrutheif.submersum) is proposed for the resurrected P.sylvaticum.

Re-assessment of type material of Plagiotheciumnovae-seelandiae Broth. and descriptions of four new Plagiothecium taxa (Bryophyta, Plagiotheciaceae) from Australasia.

A re-examination of the original collection of Plagiotheciumnovae-seelandiae described by Brotherus in 1916 indicated that this material is not homogeneous. Re-examination of the diagnosis of this species and morphological analysis supports that two separate taxa should be distinguished - Plagiotheciumnovae-seelandiaevar.novae-seelandiae and P.novae-seelandiaevar.brotherivar. nov. Also, comparisons with the original collection of Hypnumlamprostachys (= P.lamprostachys) showed differences, which supported their treatment as separate taxa. Revision of the genus Plagiothecium from Australasia (CANB, CHR, HO, MEL, WELT) and types of other species described from this part of the world (P.funale and P.lucidum) supported by the study of their diagnoses, qualitative and quantitative characteristics as well as mathematical analyses (PCA, HCA) allowed the division of the examined material into six separate groups - six separate taxa. Thereby, three distinct taxa are proposed - P.cordatumsp. nov., P.semimortuumsp. nov., and P.semimortuumvar.macquariensevar. nov. All taxa mentioned above are described in detail, their current known distribution and ecological preferences are also included. In addition, images illustrating their most important taxonomic features, as well as an original key to distinguish individual taxa are presented.

Taxonomic revision of the Plagiothecium curvifolium complex.

Supported by the examination of specimens from the entire range and by the analysis of type specimens and the diagnosis of individual names, morphological and genetic studies of the Plagiothecium curvifolium complex resulted in the conclusion that this taxon should be recognized as four separate taxa. In addition to P. curvifolium s.str., there is a variety that is proposed as a new combination-P. curvifolium var. recurvum; resurrection of the forgotten P. decursivifolium; and the description of a new species-P. imbricatum. The features that distinguish individual taxa focus primarily on: plant size; arrangement of leaves on the stem; the symmetry, dimensions, shape, concavity and folding of leaves; cell length; serration of the leaf apex; the shape of the decurrencies; the length of the sporophyte and the shape of the operculum. For all described taxa, the distribution, ecological preferences, key to their identification and detailed photographic documentation have been provided.

Plagiotheciumtalbotii, a new species from the Aleutian Islands (Alaska, U.S.A.).

Plagiotheciumtalbotii sp. nov. is described from Attu Island, Alaska, U.S.A. The newly-described species is not similar in appearance to any Northern Hemisphere species; only the habit is similar to P.platyphyllum. However, it not only occupies a different habitat than that species, but genetically and morphologically, it is clearly distinct from it. The results of DNA sequencing, a detailed description of the morphological features, illustrations, ecological preferences and currently known geographical distribution of P.talbotii are presented. The most important distinguishing morphological features of this species are: the size of the plant; dimensions and symmetry of the leaves; dimensions of cells and their areolation; entire leaf apex; and long decurrencies with some inflated cells. Additionally, we propose to place P.talbotii in section Plagiothecium, which is confirmed by genetic analysis and morphological features.

Plagiotheciumschofieldii, a new species from the Aleutian Islands (Alaska, USA).

Plagiotheciumschofieldii sp. nov. is described from the Aleutian Islands, Alaska, U.S.A. Some morphological features of this species correspond to P.lamprostachys (Southern Hemisphere species); however, Plagiotheciumschofieldii is genetically and morphologically different from this and other common Northern Hemisphere species e.g., P.denticulatum, P.platyphyllum, or P.ruthei. The most important distinguishing morphological features differentiating this species are: the arrangement of the leaves on the stem; dimensions, concavity and symmetry of the leaves; dimensions of cells and their areolation; orientation of capsules. Additionally, due to the strong concavity of the leaves, they are very often badly damaged under the microscope. We present the results of DNA research of the analyzed samples, and a detailed description of the morphological features. The new species is illustrated, and its ecological preferences and currently known geographical distribution are presented. Additionally, the authors propose to add this species to Plagiothecium section, which is confirmed by morphological features and genetic analysis.

Caliber-targeted reinterventional overdilation of iliac vein Wallstents.

BACKGROUND: Wallstents (Boston Scientific, Marlborough, Mass) are most commonly used in iliac-caval stenting. Approximately 20% of stented limbs require reintervention to correct in-stent restenosis (ISR) or stent compression (SC). Corrective balloon dilation to rated stent caliber (isodilation) is not always successful. We investigated whether modest overdilation of the Wallstent by 2 to 4 mm (10%-20%) beyond the rated diameter would yield better mechanical clearance of ISR/SC, leading to a larger flow channel, improved conductance, reduction of peripheral venous pressure, and better clinical outcome. Outflow lumen caliber exponentially influences peripheral venous pressure, a key mechanism in chronic venous disease. Beyond the mechanical effects, the rationale for overdilation rests on the theory that an improvement in flow channel at the margins may yield an outsized pressure reduction and clinical improvement. METHODS: There were 274 previously stented limbs that underwent reinterventional balloon dilation for clearance of ISR/SC during a recent 3-year period. Isodilation to rated diameter of the stent was judged effective in 71 limbs (isodilated subset); 203 limbs (overdilated subset) for which initial isodilation was ineffective underwent overdilation of the resident Wallstent by 2 to 4 mm (10%-20%) beyond the original rated diameter. IVUS planimetry was used intraoperatively to calculate SC and ISR and their subsequent clearance in the two subsets. The dilated segments were observed by clinical and duplex ultrasound examination afterward. The two subsets were compared in the following outcome measures: intraprocedural efficacy in clearing ISR/SC and achieving target lumen caliber, subsequent clinical outcomes, duplex ultrasound caliber durability, and improvement in supine foot venous pressures. This is a single-center retrospective analysis of data contemporaneously entered into a time stamped electronic medical record system. RESULTS: The median follow-up was 18 months (range, 1-35 months). Overdilation of the stent resulted in significantly better intraoperative flow channel area improvement per intravascular ultrasound. This was reflected in significantly better clinical outcome and improvement in peripheral venous pressure in the overdilated subset. Overdilation appeared to be durable up to 20 months after intervention by duplex ultrasound monitoring. CONCLUSIONS: Overdilation appears to be a useful technique to correct ISR/SC and to restore target lumen caliber during reinterventional correction of a resident iliac vein Wallstent. More durable caliber improvement, superior clinical outcome, and reduction in peripheral venous hypertension were noticed in overdilated stents compared with isodilation.

Impact of degree of stenosis in May-Thurner syndrome on iliac vein stenting.

OBJECTIVE: May-Thurner syndrome (MTS) patients with lifestyle-limiting symptoms undergo stenting of the iliac vein for relief of compressive disease. The impact of degree of stenosis on clinical symptoms and outcomes after stenting is unknown and examined in our study. METHODS: Retrospective review of contemporaneously entered data of 202 patients who underwent stenting for MTS between 2005 and 2011 was performed. Classification into three groups based on luminal area obtained by intraoperative intravascular ultrasound interrogation of the involved femoroiliocaval segments was carried out. Normal luminal diameters and areas were defined as 12 mm and 125 mm2, 14 mm and 150 mm2, and 16 mm and 200 mm2 in the common femoral, external iliac, and common iliac veins, respectively. Mild (<60%), moderate (60%-89%), and severe (>90%) compression groups were defined using the normal values noted previously and observed after stenting to evaluate outcomes. Kaplan-Meier analysis was done to assess primary, primary assisted, and secondary patencies. Visual analog scale for pain scores, grade of swelling, and Venous Clinical Severity Score (VCSS) before and after stenting at 6, 24, and 48 months were analyzed using paired t-test and Tukey test. Logistic regression was used to gauge the impact of multiple variables including degree of stenosis on stent reintervention. RESULTS: There were 55 patients who had mild, 87 patients who had moderate, and 60 patients who had severe iliac vein compression. Baseline demographic characteristics and comorbidities were similar across all groups. In addition, there was no statistically significant difference in median baseline visual analog scale score, grade of swelling, and VCSS among the groups. Compression was treated with angioplasty and stenting encompassing all areas of disease as determined by intravascular ultrasound. Stent technique involved use of Wallstent (Boston Scientific, Marlborough, Mass) only in 183 patients and Wallstent-Z stent (Cook Medical, Bloomington, Ind) combination in the remainder. No difference in median stent patency was noted on follow-up. Clinically, at 48 months, a statistically significant recurrence of pain, swelling, and worsening of VCSS were noted in the severe stenosis group but not in the other two groups. No variable was noted to have an impact on stent reintervention. CONCLUSIONS: Severity of MTS stenosis is not a predictor of initial clinical symptoms. Long term, patients with ≥90% initial MTS stenosis experience recurrence of symptoms. The degree of iliac venous stenosis does not appear to affect stent patency. Such information will help counsel patients before intervention.

Optimal sizing of iliac vein stents.

Background Iliac vein stenting has emerged as a therapeutic option in chronic venous disease. The optimal stent size is unknown but should match normal caliber at a minimum. Methods Teleology: The iliac-femoral outflow caliber was measured by Duplex in healthy volunteers to determine normal caliber. Patient IVUS data: The distribution curve of IVUS planimetry data in 345 chronic venous disease limbs was analyzed: values at the right tail end of the curve should approach normal values according to distribution theory. The optimal stent size was also projected using Poiseuille equation and Young's scaling rule. Results The optimal stent sizes in the common iliac, external iliac, and common femoral vein segments are: 16, 14, and 12 mm diameters, respectively. Conclusion Stent correction of iliac vein stenosis should aim to restore the lumen to the minimum recommended caliber during the initial procedure and later re-interventions.

Factors influencing peripheral venous pressure in an experimental model.

BACKGROUND: Peripheral venous hypertension and microvascular injury have merged as central features of chronic venous disease. Peripheral venous pressure in the lower limb is controlled by central and peripheral mechanisms. In the current manuscript, we examine the role of peripheral factors, particularly conduit capacitance compliance, focal stenosis, and arterial inflow into the calf. METHODS: An experimental venous model using Penrose tubing as a venous analogue was used where the aforementioned parameters could be manipulated. Volume-pressure curves were derived in the static mode. The dynamic model attempted to simulate key pressure parameters of lower limb venous flow. RESULTS: Decreasing compliance resulted in progressive reduction of conduit capacitance affecting both bending and stretching regimens and the relative distribution between the two, rotating the volume-pressure curve toward the x-axis. Increased postcapillary (arterial) inflow increased conduit pressure. For a given inflow, pressures varied inversely to conduit caliber. Decreased compliance led to a smaller functional caliber at working pressures. Sideline capacitance with stagnant flow connected to the flow channel (simulating calf vein network) did not influence conduit pressure. Focal stenosis increased "venous pressure" if it was narrower than "optimum outflow caliber," defined as the minimum outflow conduit caliber required to balance inflow. Percentage stenosis as traditionally calculated using adjacent lumen as denominator was uncorrelated to pressure increase. CONCLUSIONS: Conduit pressure is increased with smaller native or functional (poor compliance) caliber, focal stenosis, and increased postcapillary inflow. Many of these features appear to be present in limbs clinically suspected of chronic venous disease. The importance of the geometric factor of Poiseuille equation in pressure effects of caliber reduction and collateralization is discussed.

Deep venous thrombosis associated with caval extension of iliac stents.

BACKGROUND: It is generally difficult to place an iliac vein stent precisely at the iliocaval junction with venographic control or even with intravascular ultrasound guidance. Furthermore, mechanical properties of the Wallstent (Boston Scientific, Marlborough, Mass) can predispose precisely placed stents to distal displacement or stent collapse. Our center has thus advocated extending Wallstents 3 to 5 cm into the inferior vena cava to prevent complications of missed proximal lesions or stent migration. This technique has gradually been accepted, and concerns of jailing of contralateral flow were not initially recognized. We analyzed deep venous thrombosis (DVT) incidence following iliocaval stenting with two alternative techniques: (1) Wallstents with 3- to 5-cm extension into the inferior vena cava; and (2) a modified Z-stent (Cook Medical, Bloomington, Ind) technique, in which overlapping Wallstents end at the iliac confluence and caval extension is performed with a Z-stent placed at the top of the stack. The function of the Z-stent is to provide improved radial force at the iliocaval confluence and to prevent jailing of contralateral flow with larger stent interstices. METHODS: There were 755 limbs with consecutive Wallstent caval extensions (2006-2010) and 982 limbs with Z-stent extensions (2011-2015) analyzed for DVT incidence postoperatively. RESULTS: Demographics were similar for both groups. Mean age was 56 and 58 years in the Wallstent and Z-stent groups, respectively. There was a female predominance (Wallstent, 69%; Z-stent, 67%) and a higher incidence of left-sided disease (Wallstent, 66%; Z-stent, 56%) in both groups. There was a slightly higher incidence of post-thrombotic disease in the Z-stent subgroup (Wallstent, 53%; Z-stent, 68%). Cumulative freedom from contralateral DVT was 99% and 90% in the Z-stent and Wallstent groups, respectively (P < .001) during the 5 years following stent placement. However, all three patients with DVT contralateral to a Z-stent actually had high placement of the Wallstent across the confluence. Thus, no patients with proper Z-stent technique had a contralateral DVT. Cumulative freedom from ipsilateral DVT was 97% and 82% in the Z-stent and Wallstent groups, respectively (P < .001) during the 5 years following stent placement. The decrease in incidence of ipsilateral DVT appeared to be attributable to decreased missed distal lesions with increased operator experience and not attributable to the Z-stent itself. CONCLUSIONS: Contralateral DVT incidence was significantly lower with the Z-stent modification. In addition, the Z-stent modification provides greater radial strength at the iliac-caval confluence and simplifies simultaneous or sequential bilateral stenting. Use of proper technique and intravascular ultrasound is essential to limit the incidence of ipsilateral DVT.

Propagation of ultrashort laser pulses in water: linear absorption and onset of nonlinear spectral transformation.

We study propagation of short laser pulses through water and use a spectral hole filling technique to essentially perform a sensitive balanced comparison of absorption coefficients for pulses of different duration. This study is motivated by an alleged violation of the Bouguer-Lambert-Beer law at low light intensities, where the pulse propagation is expected to be linear, and by a possible observation of femtosecond optical precursors in water. We find that at low intensities, absorption of laser light is determined solely by its spectrum and does not directly depend on the pulse duration, in agreement with our earlier work and in contradiction to some work of others. However, as the laser fluence is increased, interaction of light with water becomes nonlinear, causing energy exchange among the pulse's spectral components and resulting in peak-intensity dependent (and therefore pulse-duration dependent) transmission. For 30 fs pulses at 800 nm center wavelength, we determine the onset of nonlinear propagation effects to occur at a peak value of about 0.12 mJ/cm(2) of input laser energy fluence.

Newly resolved relationships in an early land plant lineage: Bryophyta class Sphagnopsida (peat mosses).

PREMISE OF THE STUDY: The Sphagnopsida, an early-diverging lineage of mosses (phylum Bryophyta), are morphologically and ecologically unique and have profound impacts on global climate. The Sphagnopsida are currently classified in two genera, Sphagnum (peat mosses) with some 350-500 species and Ambuchanania with one species. An analysis of phylogenetic relationships among species and genera in the Sphagnopsida were conducted to resolve major lineages and relationships among species within the Sphagnopsida. • METHODS: Phylogenetic analyses of nucleotide sequences from the nuclear, plastid, and mitochondrial genomes (11 704 nucleotides total) were conducted and analyzed using maximum likelihood and Bayesian inference employing seven different substitution models of varying complexity. • KEY RESULTS: Phylogenetic analyses resolved three lineages within the Sphagnopsida: (1) Sphagnum sericeum, (2) S. inretortum plus Ambuchanania leucobryoides, and (3) all remaining species of Sphagnum. Sister group relationships among these three clades could not be resolved, but the phylogenetic results indicate that the highly divergent morphology of A. leucobryoides is derived within the Sphagnopsida rather than plesiomorphic. A new classification is proposed for class Sphagnopsida, with one order (Sphagnales), three families, and four genera. • CONCLUSIONS: The Sphagnopsida are an old lineage within the phylum Bryophyta, but the extant species of Sphagnum represent a relatively recent radiation. It is likely that additional species critical to understanding the evolution of peat mosses await discovery, especially in the southern hemisphere.

Environmental pollution, including toxic wastes

The veterinary practitioner has both the proficiency and the responsibility for dealing with exposure of animals to chemicals that have accidently or covertly polluted the environment. This responsibility requires maintaining animal health and preserving a wholesome human food supply, monitoring companion animals and food animals for evidence of hazardous amounts of chemicals in the environment, addressing the sanitation and public health aspects of catastrophic pollution problems, and supervising the confinement and evacuation of livestock and companion animals

Chemical Contaminants: Their Metabolism and their Residues.

Chemical contaminants which food animals may be exposed to include agricultural chemicals (e.g. insecticides, herbicides, fungicides, fumigants), industrial chemicals, metals and natural toxins (e.g. mycotoxins, phytotoxins, bacterial toxins). In the past, most intoxications of food animals resulted from natural toxicants. However, rapid development and usage of synthetic chemicals, while greatly benefitting society, have also provided new sources of potential chemical contamination. Various sources of contamination exist, but generally at least 80% of all residues in food animals are estimated to occur through the feed. Residues from water contamination or other sources occur less frequently. This paper reviews the sources, metabolism and residue problems created by various contaminants and outlines factors and therapeutic approaches utilized in alleviating some of the common chemical residues in food animals.

Fire adaptation in Neblinaria celiae (Theaceae), a high-elevation rosette shrub endemic to a wet equatorial tepui.

Neblinaria celiae (Theaceae), a rosette shrub endemic to the exceedingly rainy summit of remote Cerro de la Neblina in southern Venezuela, has a previously undescribed set of adaptations to fire. Its growth form entails sparse branching, massive terminal leaf rosettes, and thick bark. It is highly fire-tolerant, with a survival rate of 93% in a stand recently ignited by lightning, vs. 0% in seven co-occurring woody species. Survival increases sharply with rosette height, favoring a sparsely branched habit that would maximize the rate of upward growth through the sparse fuel layer supported by a sterile substrate. Thick bark and massive rosettes help protect cambial and foliar meristems from brief exposure to high temperatures. Rosettes on shorter plants are exposed to greater damage from fire near the ground and, as expected, are bigger and impound more rainwater; the greater number of leaves nearly balances the greater leaf mortality caused by fire. We relate Neblinaria's growth form to its dominance atop Neblina, to a general model for the evolution of sparse branching, and to the evolution of growth form in other tepui plants.

A review of Taxithelium (Sematophyllaceae) in Brazil

Taxithelium is represented in Brazil by three species. Each species is described and illustrated and its distribution in Brazil is mapped. Taxithelium planum (Brid. ) mitt. is weedy but mainly confined to the low elevations of Amazonia; T. pluripunctatum(Ren. & Card.) Buck is reported for the first time for Brazil from three localities; T. juruense (Broth.) Broth. is apparently endemic to Acre.

Taxithelium é representado no Brasil por três espécies. Cada espécie é ilustrada e sua distribuição mapeada. Taxitheliu planum (Brid.) Mitt. é muito frequente, embora principalmente limitada às elevações baixas da Amazônia. Ela é reconhecida pelos filídios ovatos e vélulas alares relativamente numerosas. A forma do ápice dos filídios e o desenvolvimento alar são dependentes do substrato e umidade. Taxithelium plutipuctatum (Ren. & Card.) Buck e registrada pela primeira vez para o Brasil em três localidades; ela é reconhecida pelos filídios frouxamente dispostos e com pouco desenvolvimento alar. Taxithelium juruense (Broth.) Broth, é aparentemente endêmica no Acre. Ela é distinguida pelas células papilosas no ápice do filídio e pelas margens enroladas do filídio.