Root-associated fungi of Arabidopsis thaliana and Microthlaspi perfoliatum

Root-associated fungi, with the focus on endophytic species, were isolated from healthy Arabidopsis thaliana and Microthlaspi perfoliatum plants collected at different locations in Germany. A large number of fungal taxa were discovered with a small-scale approach. This provides additional evidence that root-associated and endophytic fungi are common in Brassicaceae. The most prevalent genera associated with A. thaliana roots were Trichoderma and Fusarium, while the roots of M. perfoliatum were dominated by different species of Fusarium and Penicillium. Differences in species composition and richness might be due to preferences and life-cycle of the two plant species. Strains of endophyte species that did not have closely related species in GenBank searches and those already known as root endophytes were chosen for preliminary co-cultivation experiments using germinating host plants on agar medium to observe effects on plant growth and health. Under these conditions several fungal isolates had an adverse effect on plant growth and health, especially on Arabidopsis thaliana. Some isolates did not adversely affect biomass during initial plant growth, while they altered the shoot-root ratio in favour of the shoot, especially in Microthlaspi perfoliatum. These strains are promising candidates for future research on endophytes as they might have some effects in Brassicaceae that are similar to mycorrhizal fungi. They are also promising candidates for investigating interactions with their host plants.     

Chronic Pancreatitis with Benign Biliary Obstruction: Management Issues

Background

Benign biliary obstruction (BBO) is an important complication in patients with advanced chronic pancreatitis (CP). Its presentation varies from an incidental finding to overt jaundice. Thus it presents certain management issues. The present study was therefore performed to analyze the clinical presentation and management of biliary obstruction in patients with CP.

Methods

Retrospective analysis was performed from a prospectively collected database of 155 CP patients managed at our institute from October 2003 to June 2012.

Results

Among 43 (28 %) CP patients with biliary obstruction, 3 patients had evidence of malignancy on follow-up examination and were excluded from the final analysis. The various presentations include chronic nonprogressive elevation of serum alkaline phosphatase (SAP) (n = 15), a progressive increase in SAP with episodes of jaundice (n = 17), and persistent jaundice (n = 8). Of 15 patients with chronic nonprogressive elevation of SAP, 5 were managed conservatively, and the remaining 10 underwent only a pancreatic drainage procedure. During a median follow-up of 41 months (range 11–90 months), none of the 15 patients developed complications related to biliary obstruction. All patients with progressive increase in SAP levels and persistent jaundice underwent the biliary drainage procedure [choledochojejunostomy (CDJ, n = 20) and choledochoduodenostomy (CDD, n = 3)]. During a median follow-up of 30 months (range 10–89 months), two patients died of unrelated causes and two patients had an asymptomatic elevation of SAP.

Conclusions

BBO is common in patients with CP; however, biliary drainage is not indicated for chronic nonprogressive elevation of SAP. In patients with a progressive increase in SAP or persistent jaundice, both CDJ and CDD provide effective biliary drainage.     

Reversibility of Retinal Microvascular Changes in Severe Falciparum Malaria

Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted.The pathogenesis of coma in falciparum malaria and its rapid reversibility are potential targets for adjunctive therapies, but they are not well-understood. Microvascular obstruction is probably an important contributor. The brain microvasculature is relatively inaccessible; it can be studied in detail only at post-mortem. Similarly, microvascular obstruction in the retina is thought to be a major contributor to the unique retinopathy of severe falciparum malaria, and, because it is easily visualized in living subjects, in-depth study is providing new and valuable insights. We describe an adult patient with cerebral malaria who had prominent retinal changes with some previously unrecognized features that resolved on recovery.A 24-year-old male truck driver from Orissa, India was admitted with severe Plasmodium falciparum malaria (parasitemia = 0.3%) with coma, generalized convulsions, hyperlactatemia, renal failure, and black urine. He had no prior medical history. Retinal photography showed bilateral patchy macular whitening with corresponding capillary non-perfusion and leakage of fluorescein caused by blood retinal barrier breakdown on fluorescein angiography (Figure 1). He was treated with intravenous artesunate, and from recovery of consciousness on day 3 to discharge, his visual acuity was markedly reduced (counting digits only), with loss of red–green color vision. Repeat examination on day 55 showed that the retinal changes, angiogram abnormalities, and visual deficits had resolved (acuity 6/9 bilaterally and normal color vision). Blood vessel tortuosity measured in three arteries and three veins by a single blinded observer tracing the center line of vessels between branch points in matched pairs of retinal photographs using Adobe Photoshop CS4 (Adobe Systems, San Jose, CA)¹ was greater on day 0 than day 55 (mean ratios of vessel widths measured at 10 points in each vessel; 1.226 in arteries and 1.172 in veins; vessel lengths were 1.043 and 1.035). These differences are similar to those found previously in diabetic macular edema.¹Open in a separate windowFigure 1.(A and B) Retinal photographs and (C and D, arterial phase; E and F, late phase) fluorescein angiograms of the left eye. On day 3, increased vessel thickness and tortuosity plus (A) patchy macular whitening with corresponding areas of (C) reduced perfusion and (E) fluorescein leakage were seen. On day 55, normal vessels, (B) no whitening, and (D) normal perfusion around the fovea with (F) no leakage of fluorescein were seen.Malarial retinal whitening is thought to be caused by hypoxic opacification of the retina after obstruction of small blood vessels by sequestered parasites.^2,3 It is similar to patchy ischemic retinal whitening (PIRW), a transient early sign of central retinal vein occlusion (CRVO)² thought to represent intracellular edema of overlying retinal intermediary neurones.⁴ The degree of retinal whitening in adults and children correlates with severity of malaria and peripheral blood lactate.^5,6 Hyperlactatemia is common in severe malaria and at least partly caused by obstruction of the systemic microcirculation by sequestered parasites. Cerebrospinal fluid lactate concentrations are also raised in cerebral malaria, and in those cases it is predictive of mortality.⁷The appearance and distribution of retinal whitening are unique to severe falciparum malaria. Typically, there are multiple small lesions most prominent in the macula, particularly temporal to the fovea. This area is a watershed between the superior and inferior retinal vascular arcades and particularly vulnerable to ischemic insults. Midperipheral involvement in malaria distinguishes it from PIRW, Purtscher''s retinopathy, and cotton wool spots (sometimes also seen in malaria), which are distributed particularly around the optic disk and typically more opaque. Malarial retinopathy is considered reversible,^8,9 but this case is the first published photographic evidence of reversibility.The angiogram in this patient showed that the whitening corresponds closely to capillary non-perfusion. This finding has not been described previously in adults but is common in Malawian children with cerebral malaria.¹⁰ Post-mortem studies in Malawi have found retinal blood vessels in cerebral malaria to be packed with sequestered parasites,¹¹ similar to findings in the brain in adults.¹² Because retinal whitening⁹ and central nervous system (CNS) sequestration^13,14 are particularly prominent in patients with malarial coma (cerebral malaria), this finding suggests that small blood vessel CNS ischemia plays a major role in pathogenesis. In survivors, malarial coma is rapidly reversible and, as seen in the retina in this case, reversal of blood vessel obstruction is a plausible contributor.This patient had mildly increased tortuosity of retinal blood vessels that decreased on recovery. Although increased vascular tortuosity has not been well-described in malaria, it is a recognized feature of other vascular occlusive diseases of the retina. Vessel tortuosity is caused by a combination of vessel dilation from radial stretching and the vessel taking a more serpentine path because of longitudinal stretching.¹⁵ Several pathogenic mechanisms have been proposed for increased retinal vascular tortuosity. They include (1) increased blood flow in anemia, (2) early angiogenesis caused by ischemia or inflammation and (3) dysregulation of vascular tone caused by microvascular obstruction and relative hypoxia in diabetic retinopathy, and (4) venous congestion causing elevated vascular pressure and dilatation of blocked vessels in CRVO and raised intracranial pressure resulting in central retinal vein compression. In malaria, anemia is common, uninfected red blood cells have reduced deformability, and sequestered parasites cause microvascular and venular obstruction. Angiogenesis is probably unimportant over the short timescale.¹Increased vascular tortuosity has not been well-described previously in severe falciparum malaria, possibly because the normal appearance of retinal vessels varies significantly between individuals and subtle changes are difficult to identify. Ophthalmoscopy revealed engorgement and tortuosity of retinal veins in 26% of children with cerebral malaria in Ghana, which mostly resolved by 1 week.⁸ In our patient, comparison of retinal photographs provided a more objective measure. Means of quantifying vessel tortuosity using computer-aided image processing are under development.The angiogram in this patient showed focal leakage of fluorescein across the blood–retinal barrier (BRB) in areas of non-perfusion, suggesting a common etiology. The BRB is analogous to the blood–brain barrier, which is also mildly disrupted in cerebral malaria. Leakage from larger retinal vessels crossing ischemic areas is a well-known phenomenon in retinal ischemia. The significance of this finding as a contributor to the pathogenesis of malarial coma is not known. More angiographic studies are needed.This patient had decreased visual acuity, which had resolved at follow-up. Although it is not possible to give a cause, it is the first report of an association between macular retinal whitening and decreased visual acuity with subsequent recovery.Additional studies of malarial retinopathy have great potential to enhance our understanding of vascular changes in severe malaria. To maximize their impact, studies should use retinal photography, where possible, to allow detailed examination of the full range of fundus signs by multiple blinded observers. This examination should be done both acutely and at follow-up. Fluorescein angiography provides a highly detailed map of CNS retinal perfusion. There is a need for additional detailed studies to include assessment of vascular tortuosity to investigate its role as a potential early and sensitive marker in studies of severe malaria.The rate of reversibility of malarial retinopathy has potential as an end point in intervention studies of severe malaria, particularly for adjunctive therapies that directly target the pathogenesis. Additional information on the speed of reversibility of the various components of malarial retinopathy is needed, and studies are underway to investigate this.     

Dynamical facilitation governs glassy dynamics in suspensions of colloidal ellipsoids

One of the greatest challenges in contemporary condensed matter physics is to ascertain whether the formation of glasses from liquids is fundamentally thermodynamic or dynamic in origin. Although the thermodynamic paradigm has dominated theoretical research for decades, the purely kinetic perspective of the dynamical facilitation (DF) theory has attained prominence in recent times. In particular, recent experiments and simulations have highlighted the importance of facilitation using simple model systems composed of spherical particles. However, an overwhelming majority of liquids possess anisotropy in particle shape and interactions, and it is therefore imperative to examine facilitation in complex glass formers. Here, we apply the DF theory to systems with orientational degrees of freedom as well as anisotropic attractive interactions. By analyzing data from experiments on colloidal ellipsoids, we show that facilitation plays a pivotal role in translational as well as orientational relaxation. Furthermore, we demonstrate that the introduction of attractive interactions leads to spatial decoupling of translational and rotational facilitation, which subsequently results in the decoupling of dynamical heterogeneities. Most strikingly, the DF theory can predict the existence of reentrant glass transitions based on the statistics of localized dynamical events, called excitations, whose duration is substantially smaller than the structural relaxation time. Our findings pave the way for systematically testing the DF approach in complex glass formers and also establish the significance of facilitation in governing structural relaxation in supercooled liquids.The transformation of liquids into glasses is as ubiquitous as it is enigmatic. From the formation of obsidian during volcanic eruptions (1) and fabrication of superstrong metallic glasses (2) to exotic forms of slow dynamics in crystals of colloidal dimers (3) and Janus particles (4), glass formation pervades nature, industry, and academia. A vast majority of molecular glass-forming materials exhibit anisotropy in shape and interparticle interactions, which often has a profound influence on their glassy dynamics. The rapidly expanding repertoire of chemists has made it possible to design colloidal particles of desired shape and interactions that can serve as realistic experimental analogs of these molecular liquids (5). By contrast, prominent theories like the Adam–Gibbs (6) theory, random first-order transition (RFOT) theory (7, 8), and the dynamical facilitation (DF) theory (9, 10) have been tested predominantly on spherical glass formers with isotropic interactions, which exhibit gross features of glassy dynamics, but fail to capture the nuances of vitrification in complex systems.The discovery of growing static (11–16) and dynamic (17–21) length scales appears to support the thermodynamic perspective of the Adam–Gibbs and RFOT theories. However, the growth in static length scales over the dynamical range accessible to numerical simulations is often minuscule and much smaller than the corresponding growth in dynamic length scales (21, 22). This renders any causal connection between growing static length scales and growing timescales doubtful (22). Moreover, recent simulations (23) and colloid experiments (24) have shown that growing dynamical correlations in the form of string-like cooperative motion emerge naturally within the purely kinetic approach of the DF theory. To compound matters further, facilitation is present even within the RFOT framework, albeit as a consequence of slow dynamics rather than a cause (25). Thus, although DF has been shown to exist (23, 24, 26–29), its relative importance as a mechanism of structural relaxation is still debated (30–32). The application of the DF approach to complex glass formers will therefore not only enhance our understanding of glass transitions in these systems, but also help ascertain the relevance of facilitation in governing structural relaxation.Here, we apply the DF theory to elucidate glass formation in suspensions of colloidal ellipsoids with repulsive as well as attractive interactions. The DF theory claims that structural relaxation in glass-forming liquids proceeds via a process known as dynamical facilitation, whereby localized mobile regions, termed excitations, mediate motion in neighboring regions in a manner that conserves mobility (9, 10). We first show that the notions of localized excitations and facilitated dynamics can be extended even to orientational relaxation. Next, we demonstrate that the spatial decoupling of dynamical heterogeneities (DHs) observed in colloid experiments stems from the spatial decoupling of rotational and translational facilitation. Most importantly, the DF theory can predict the existence of recently observed reentrant glass transitions (33) from the density dependence of the concentration of excitations. Our findings not only highlight the importance of facilitated dynamics in anisotropic glass formers but also reinforce the claim that, in the broader context of the glass transition, facilitation dominates structural relaxation.     

Alpha-adrenoceptor changes after oestrogen treatment in platelets and other tissues in female rabbits

alpha 2-Adrenoceptors on blood platelets have been widely used as a model for alpha-adrenoceptors in less accessible tissues. The effect of oestrogen (200 micrograms/day intramuscularly) on alpha 2-adrenoceptor number and function was studied in immature female rabbits. alpha 2-adrenoceptor number was measured in whole platelets, and membrane preparations of forebrain, hindbrain, spleen and kidney by radioligand binding. alpha 2-Adrenoceptor function was examined by measuring platelet aggregation in vitro and circulatory responses to selective alpha 2-adrenoceptor agonists in vivo. Oestrogen treatment resulted in a significant decrease in platelet alpha 2-adrenoceptor number and function. However, no changes were observed either in receptor number in other tissues or in responses to alpha 2-agonists in vivo. The results suggest that oestrogen modulation of rabbit platelet alpha 2-adrenoreceptor number and function may be different from that of brain, kidney and spleen. Caution should be exercised in extrapolating results from platelets to alpha-adrenoceptors at other sites.     

Surgical Outcomes of Primary Versus Post-Neoadjuvant Chemotherapy Breast Conservation Surgery: A Comparative Study from a Developing Country

Introduction

In India and other developing countries, breast conservation surgery (BCS) rates in breast cancer patients are low due to advanced disease at presentation and misconceptions about BCS outcomes. Many patients presenting with large or locally advanced breast cancers (LABC) can be offered post-neoadjuvant chemotherapy (NACT) BCS, safety of which is not as well established as that of primary BCS. This retrospective study compared pathological and surgical outcome parameters in patients undergoing primary and post-NACT BCS.

Methods

All non-metastatic breast cancer patients undergoing BCS during 2011–2015 with 1-year follow-up were included. Outcome parameters in form of margin infiltration, ipsilateral breast tumor recurrence (IBTR) rates and IBTR-free survival were compared between primary and post-NACT BCS patients groups.

Results

One hundred and twenty-nine patients underwent BCS; 95 underwent primary and 34 post-NACT BCS. Patients in both groups underwent similar multimodality treatment as per institutional protocols. Post-NACT patients more frequently required oncoplastic volume displacement or replacement surgery (p = 0.002). Re-excision of infiltrated margins was needed more frequently in primary BCS compared with post-NACT BCS group (14.4 vs. 8.8%; p = 0.40). IBTR (Mean follow-up = 30.7 months) was seen in 8.8% post-NACT patients compared with 2.1% primary BCS (p = 0.114). IBTR-free survival did not differ significantly between the groups in stage-wise comparison.

Conclusion

Post-NACT BCS is safe even in large tumors and LABC, though many require oncoplastic procedures for satisfactory cosmesis. In a developing country where many patients present with large breast cancers or LABC, the benefits of BCS can be offered to a majority with the help of NACT, without compromising the chances of cure.