Otoliths are frequently used to infer environmental conditions or fish life history events based on trace-element concentrations. However, otoliths can be comprised of any one or combination of the ...three most common polymorphs of calcium carbonate-aragonite, calcite, and vaterite-which can affect the ecological interpretation of otolith trace-element results. Previous studies have reported heterogeneous calcium carbonate compositions between left and right otoliths but did not provide quantitative assessments of polymorph abundances. In this study, neutron diffraction and Raman spectroscopy were used to identify and quantify mineralogical compositions of Chinook salmon Oncorhynchus tshawytscha otolith pairs. We found mineralogical compositions frequently differed between otoliths in a pair and accurate calcium carbonate polymorph identification was rarely possible by visual inspection alone. The prevalence of multiple polymorphs in otoliths is not well-understood, and future research should focus on identifying otolith compositions and investigate how variations in mineralogy affect trace-element incorporation and potentially bias environmental interpretations.
Fish otoliths, or ear bones, are comprised of the CaCO
polymorphs (aragonite, calcite and vaterite), which can occur either alone or in combination. The polymorph phase abundance in an otolith ...depends on, as yet, unexplained genetic and environmental factors. Most fish otoliths are comprised of the densest CaCO
polymorph, aragonite. Sturgeon otoliths, on the other hand, contain significant amounts of the rare and the structurally enigmatic polymorph, vaterite. Sturgeon otoliths are frequently comprised of agglomerations of small microcrystalline vaterite spherulites (<300 μm in diameter), that range in shape from nearly perfect spheres to oblate spheroids. These spherulites are similar to the synthetic vaterite microspheres employed in laser trapping applications. Vaterite spherulites from both hatchery-reared (juvenile) and wild (adult) Lake Sturgeon exhibit extreme crystallographic texture as evidenced by X-ray diffraction patterns and their reconstructed pole-figures determined here. The vaterite crystallites making up the spherulites have excellent registry in both the axial and equatorial directions. Whether synthesized or natural, the texture manifested in these spherulites suggests that vaterite nucleates and grows similarly in vivo otolith formation as well as from laboratory synthesis. The uniaxial optical character of the vaterite spherulites, confirmed by these diffraction experiments and combined with their large birefringence, makes them well suited for laser trapping applications.
The complex nature of growth and decomposition in microbial mats results in a broad range of microbial preservation. Such taphonomic variability complicates both the description of microbial elements ...preserved within geologic materials and the potential interpretation of microbial biomarkers. This study uses a taphonomic assessment to explore the preservation of different microbial components within silicified microbial mats of the late Mesoproterozoic (~1.0 Ga) Angmaat Formation, Bylot Supergroup, Baffin Island. The Angmaat Formation consists of unmetamorphosed and essentially undeformed strata that represent intertidal to supratidal deposition within an evaporative microbial flat. Early diagenetic silicification preserved microbial communities across a range of environments, from those episodically exposed to persistently submerged. Here, we present the development of a new methodology involving the use of high-resolution image mosaics to investigate the taphonomy of microfossils preserved in these mats. A taphonomic grade is assigned using a modified classification that accounts for both the taphonomic preservation state (good, fair, poor) of individual microfossils, as well as the degree of compaction of the overall mat. We show that although various taphonomic states occur within each of the silicified mats, the overall taphonomic assessment differentiates between well-preserved mats that are interpreted to have been silicified during active growth, to highly degraded and compacted mats that are interpreted to represent preservation during later stages of biological decomposition. These data indicate that even small changes in the timing of silicification may have substantial implications on our identification of microbial biomarkers and, therefore, our interpretation of early Earth ecosystems.
Cutaneous lymphoid hyperplasia (CLH) has been proposed to be the benign end of a continuum of lymphoproliferative disorders with cutaneous lymphoma at its malignant extreme. An intermediate ...condition, known as “clonal CLH,” was first recognized by us and shown to be a transitional state capable of eventuating in overt lymphoma. To better determine the prevalence of dominant clonality and risk of lymphoma among CLH cases, we studied the immunohistology and clonality of fresh-frozen samples from 44 CLH patients referred to a multidisciplinary cutaneous lymphoproliferative disorders program. Using a large panel of lymphoid markers, the cases were divided into 38 typical mixed B-cell/T-cell type CLH and 6 T-cell-rich type (T-CLH), the latter containing > 90% T cells. Of the 44 patients, 38 had solitary or localized lesions (4 cases of T-CLH), and 6 had regional/generalized lesions (2 cases of T-CLH). Forty cases were of idiopathic etiology. Suspected etiologies among 4 other cases included mercuric tattoo pigment, doxepin, clozapine, and bacterial infection. Immunoglobulin heavy chain (IgH) and T-cell receptor (TCR)-gamma gene rearrangements (GR) were studied using polymerase chain reaction assays, which are approximately 80% sensitive. Overall, 27 cases (61%) showed clonal CLH: 12 IgH+ (27%; 3 cases of T-CLH); 13 TCR+ (30%; 1 case of T-CLH); and 2 IgH+/TCR+ (4%; neither case was T-CLH). Two cases (4%; 1 case of T-CLH) progressed to cutaneous B-cell lymphoma. Both of these patients presented with regional lesions. Our findings indicate that clonal overgrowth is common in CLH, links CLH to lymphoma, and probably involves both B- and T-cell lineages (although TCR GR by B cells and vice versa could not be ruled out). The high prevalence of dominant clonality in our series may have resulted from the sensitivity of our PCR assays as well as patient selection.
•Barite can record temporal changes in porewater δ34SSO4 over small spatial scales.•SIMS analyses reveal cyclical changes in δ34S values along barite growth axes.•Large δ34S variations coincide with ...morphological changes in barite aggregates.•Intra-aggregate δ34SBaSO4 fluctuation record a dynamic seepage history.
Authigenic carbonate and barite crusts were analyzed from recently discovered cold seeps on the Lofoten-Vesterålen (LV) continental slope, northern Norway. Carbonate phases in these crusts are methane-derived Mg-calcite and aragonite. Scanning electron microscopy (SEM) was used to petrographically characterize cold seep crusts, and secondary ion mass spectrometry (SIMS) was used to measure the microscale sulfur isotope composition (δ34S values) of authigenic barite. The mean δ34SBaSO4 value from SIMS spot analyses is 70‰ (n = 303), significantly elevated with respect to seawater sulfate (∼21‰). The δ34S values can vary more than 40‰ within individual barite aggregates (< 250 μm) and more than 50‰ within cm-scale samples. δ34SBaSO4 values in layered barite aggregates are most variable parallel to growth axes, with minimal variability in the perpendicular direction; fluctuations in δ34SBaSO4 values along growth axes are inferred to record temporal changes in sulfate distillation during barite precipitation. In layered barite aggregates, δ34SBaSO4 values frequently approach ∼90‰, but at these high δ34S values, barite dissolution features become increasingly prevalent and may reflect an upper limit for porewater 34SSO4 enrichment while maintaining barite saturation in this system. We suggest the primary forcing affecting sulfate distillation is varying activity of anaerobic oxidation of methane coupled to sulfate reduction (AOM-SR) due to temporal changes in cold seep methane flux. These findings provide the first semi-continuous geologic proxy for paleo-methane flux on the Lofoten-Vesterålen continental margin and suggest methane advection rates varied considerably over the course of carbonate-barite crust formation. In addition to systematic microscale changes in δ34SBaSO4 values, periodic intra-aggregate dissolution features indicate a dynamic seepage environment with two or more periods of enhanced methane flux in recent geological history.
The definitive diagnosis of mycosis fungoides (MF)–type cutaneous T-cell lymphoma (CTCL) is difficult because a cumulative set of information is typically required: clinical features, histopathology, ...and special diagnostic tests (typically immunophenotyping and T-cell receptor gamma TCRγ gene rearrangement). Fresh tissue is not always available for the special tests. We report a simple and readily available procedure evaluating the staining pattern on formalin-fixed, paraffin-embedded skin that can help with the diagnosis of patch/plaque stage MF. We reviewed 92 cases of MF or probable MF that had clinical information, immunophenotyping and TCRγ gene rearrangement studies and that had been evaluated in our multidisciplinary lymphoma conference. We used antibodies to the isoforms of CD45, CD45RO for mature T cells and CD45RB for subsets of T cells. When atypical CD45RB-positive/CD45RO-negative cells were seen in nonspongiotic epidermis, the individuals had a high cumulative clinical and histologic score for MF. In contrast, 15 cases of known contact dermatitis showed a reactive pattern of both CD45RB- and CD45RO-positive cells in spongiotic epidermis. We compared the epidermal CD45RB-positive/CD45RO-negative staining pattern with CD7 deficiency by immunophenotyping and TCRγ gene rearrangement, two commonly used methods in the diagnosis of MF. The epidermal CD45RB-positive/CD45RO-negative staining pattern is comparable and may be better in equivocal cases of possible MF. Therefore immunostaining for CD45RB and CD45RO on paraffin sections is a simple, reliable, and convenient modality in the diagnosis of MF.
The environmental and biological factors that influence the precipitation and composition of geologic proxies are often assumed to be minimally variable relative to the spatial and temporal domain of ...individual samples (ca. millimeters to centimeters). While this presumption may apply to many pelagic environments, it may not be appropriate for methane cold seep sites. Methane cold seeps are localized environments that can transport large quantities of dissolved methane - a potent greenhouse gas - toward the seafloor and, in turn, sustain high rates of anaerobic oxidation of methane by sulfate reduction (AOM-SR). The concurrent transport of anoxic seep fluids, diffused seawater sulfate, and AOM-SR activity can produce steep gradients in the concentration and isotopic (δ³⁴S) composition of dissolved sulfate near the seafloor. The precipitation of methane-derived authigenic carbonate (MDAC) polymorphs (e.g. aragonite and calcite; CaCO3) and δ³⁴S values of reduced and oxidized sulfur in authigenic pyrite (FeS2) and barite (BaSO4), respectively, have been used gauge the magnitude of past AOM-SR activity and infer paleo methane seep conditions. However, there is growing evidence these geologic proxies can possess considerable mineralogic, textural, elemental, and isotopic variability over small spatial scales (micrometers to millimeters). These microscale heterogeneities can potentially result from either steady-state or non-steady-state conditions depending on the precipitation interval of a given sample. The overarching aim of this dissertation is to empirically evaluate the potential for increased environmental understanding derived from microscopic (< 1 mm) δ³⁴S heterogeneities in authigenic seep barite (δ³⁴SBaSO4) and pyrite (δ³⁴SPyr) obtained by in-situ secondary ion mass spectrometry (SIMS) measurements paired with petrographic analyses. By coupling petrographic and δ³⁴S assessments, the relative timing of microscale heterogeneities can often be inferred and used to further constrain the geochemical evolution of the precipitation environment. SIMS δ³⁴S analyses also reveal unprecedented degrees of microscale δ³⁴SBaSO4 variability and 34SBaSO4 enrichment compared to previous bulk δ³⁴SBaSO4 measurements.Additionally, a novel 1D biogeochemical model was constructed to describe the reactive transport of advected methane and barium and diffused sweater sulfate and to investigate potential causes of measured microscale δ³⁴SBaSO4 heterogeneities. The model explicitly tracks the distillation of porewater sulfate due to AOM-SR activity and both the precipitation depth and δ³⁴SBaSO4 value of seep barite. Modeling results indicate that the stratigraphic interval of barite precipitation is often narrow (millimeters to centimeters) and that large δ³⁴SBaSO4 variability (> 90‰) can arise from steady-state precipitation conditions. Moreover, both barite precipitation rates and ³⁴S enrichment are sensitive to minor – and potentially foreseeable – changes in precipitation conditions. Model results indicate that bulk sampling methods may potentially obscure microscale δ³⁴SBaSO4 variability produced under steady-state and non-steady-state precipitation conditions.Similar to seep barite, SIMS analyses reveal that δ³⁴SPyr values can vary significantly within an individual seep sample (< 1” diameter). We find that SIMS δ³⁴SPyr values can differ significantly between pyrite hosted in calcitic- and aragonitic- MDAC. By assessing authigenic seep pyrite with respect to textural layering in MDAC phases, the relative timing of δ³⁴SPy variability can often be inferred. We present a qualitative model for how δ³⁴SPyr values, petrographic features, and carbonate-associated sulfate (CAS) concentrations are potentially interrelated by temporal changes in AOM-SR activity and seawater diffusivity. Successive changes in CAS intensity were measured in aragonitic-MDAC using mono-energy micro-X-Ray fluorescence (µ-XRF) mapping. We ultimately suggest that successive changes in SIMS δ³⁴SPy values and CAS intensity can be used to distinguish the effects of porosity and AOM-SR activity on porewater ³⁴S enrichment. At first glance, the measured and modeled degrees of microscale δ³⁴S variability in seep pyrite and barite could call into question the utility of these proxies for inferring past seep conditions. However, under steady-state precipitation conditions, modeling results indicate that even large aliquots (e.g. 1 cm3) that incorporate a wide range of δ³⁴SBaSO4 values (e.g., > 60‰) can still return precipitation-weighted δ³⁴SBaSO4 values that are similar to the modal ³⁴SBaSO4 value of precipitates (± 5‰). Additionally, SIMS δ³⁴SPy analyses seem to support established interpretations of MDAC mineral phases. There also appears to be a relationship between microscale textural variability in aragonitic-MDAC and seep barite that correlates with proportionately microscale changes in CAS concentrations and ³⁴SBaSO4 values, respectively. This apparent relationship may indicate that petrographic analyses can be used to rapidly screen authigenic seep minerals prior to chemical and isotopic analyses. Collectively, we suggest that these microscale textural and compositional heterogeneities can provide new and valuable insights into the geochemical evolution and dynamic nature of active methane seep environments.
Use of Intravenous Albumin Callum, Jeannie; Skubas, Nikolaos J.; Bathla, Aarti ...
Chest,
August 2024, Letnik:
166, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Albumin is used commonly across a wide range of clinical settings to improve hemodynamics, to facilitate fluid removal, and to manage complications of cirrhosis. The International Collaboration for ...Transfusion Medicine Guidelines developed guidelines for the use of albumin in patients requiring critical care, undergoing cardiovascular surgery, undergoing kidney replacement therapy, or experiencing complications of cirrhosis.
Cochairs oversaw the guideline development process and the panel included researchers, clinicians, methodologists, and a patient representative. The evidence informing this guideline arises from a systematic review of randomized clinical trials and systematic reviews, in which multiple databases were searched (inception through November 23, 2022). The panel reviewed the data and formulated the guideline recommendations using Grading of Recommendations Assessment, Development, and Evaluation methodology. The guidelines were revised after public consultation.
The panel made 14 recommendations on albumin use in adult critical care (three recommendations), pediatric critical care (one recommendation), neonatal critical care (two recommendations), cardiovascular surgery (two recommendations), kidney replacement therapy (one recommendation), and complications of cirrhosis (five recommendations). Of the 14 recommendations, two recommendations had moderate certainty of evidence, five recommendations had low certainty of evidence, and seven recommendations had very low certainty of evidence. Two of the 14 recommendations suggested conditional use of albumin for patients with cirrhosis undergoing large-volume paracentesis or with spontaneous bacterial peritonitis. Twelve of 14 recommendations did not suggest albumin use in a wide variety of clinical situations where albumin commonly is transfused.
Currently, few evidence-based indications support the routine use of albumin in clinical practice to improve patient outcomes. These guidelines provide clinicians with actionable recommendations on the use of albumin.
To evaluate the toxic effects and maximum tolerated dose of topical carmustine 1,3-bis(2-chloroethyl)-1-nitrosourea following intravenous O6-benzylguanine in the treatment of cutaneous T-cell ...lymphoma (CTCL), and to determine pharmacodynamics of O6-alkylguanine DNA alkyltransferase activity in treated CTCL lesions.
Open-label, dose-escalation, phase I trial.
Dermatology outpatient clinic and clinical research unit at a university teaching hospital.
A total of 21 adult patients (11 male, 10 female)with early-stage (IA-IIA) refractory CTCL, mycosis fungoides type, treated with topical carmustine following intravenous O6-benzylguanine.
Treatment once every 2 weeks with 120 mg/m(2) intravenous O6-benzylguanine followed 1 hour later by whole-body, low-dose topical carmustine starting at 10 mg, with 10-mg incremental dose-escalation in 3 patient cohorts. Cutaneous T-cell lymphoma lesional skin biopsy specimens were taken at baseline and 6 hours, 24 hours, and 1 week after the first O6-benzylguanine infusion for analysis of O6-alkylguanine-DNA alkyltransferase activity.
Clinical response measured by physical examination and severity-weighted assessment tool measurements, safety data acquired by review of adverse events at study visits, and O6-alkylguanine-DNA alkyltransferase activity in treated lesion skin biopsy specimens.
A minimal toxic effect was observed through the 40-mg carmustine dose level with 76% of adverse events being grade 1 based on the National Cancer Institute Common Terminology Criteria for Adverse Events. Mean baseline O6-alkylguanine-DNA alkyltransferase activity in CTCL lesions was 3 times greater than in normal controls and was diminished by a median of 100% at 6 and 24 hours following O6-benzylguanine with recovery at 1 week. Clinical disease reduction correlated positively with O6-alkylguanine-DNA alkyltransferase activity at 168 hours (P=.02) and inversely with area under the curve of O6-alkylguanine-DNA alkyltransferase over 1 week (P=.01). Twelve partial responses and 4 complete responses were observed (overall response, 76% 95% CI, 0.55-0.89). Five patients discontinued therapy owing to adverse events with a possible, probable, or definite relationship to the study drug.
O6-benzylguanine significantly depletes O6-alkylguanine-DNA alkyltransferase in CTCL lesions and in combination with topical carmustine is well tolerated and shows meaningful clinical responses in CTCL at markedly reduced total carmustine treatment doses.
Background: Folliculotropic mycosis fungoides (MF) is a rare variant of cutaneous T-cell lymphoma, MF type, characterized by atypical lymphocytes preferentially infiltrating the hair-follicle ...epithelium relative to the epidermis.
Observations: We describe a rare case of folliculotropic MF involving the central nervous system. This is also the first case in which laser capture microdissection was used to show that the atypical lymphocytes within the hair-follicle epithelium were part of the same tumor clone present in other tissue compartments.
Conclusions: In reviewing the literature describing atypical lymphocytes infiltrating hair-follicle epithelium relative to the epidermis, we encourage the use of the term
folliculotropic mycosis fungoides. Our case also supports previous findings that central nervous system involvement can occur in advanced MF. The successful procurement and analysis of atypical lymphocytes from hair-follicle epithelium by laser capture microscopy ushers in a new era in molecular diagnostics. (J Am Acad Dermatol 2003;48:238-43.)
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