Deposits In Association Research Articles

Cryolite as a Reference Mineral of Rare Metal Mineralization: An Experimental Study

Abstract Phase relations and the distributions of rare earth elements (REE), Sc, Y, and Li between aluminofluoride and aluminosilicate melts in the model granite system Si–Al–Na–K–Li–F–O–H were experimentally studied at 700°C, 1 and 2 kbar, and water contents of 3 to 50 wt %. Our original and available literature experimental data on phase relations in the granite system saturated with water and fluorine and containing trace elements are compared with the mineral assemblages of rare-metal cryolite-bearing granites from the Zashikhinsky, Katugin, and Ulug-Tanzek deposits in eastern Siberia. Liquid immiscibility between granite and salt aluminofluoride melts, which occurs at high contents of fluorine and lithium in the system, is proved to facilitate the accumulation of rare elements in salt cryolite-like melts. At a temperature of 700°C and pressures of 1 and 2 kbar, aluminofluoride melt in the granite system crystallizes and forms cryolite. Fluorine-bearing minerals of trace and rare earth elements, such as pyrochlore and gagarinite, occur at these deposits in association with cryolite and lithium micas. Comparison of experimental data and natural observations provides arguments in support of the hypothesis that liquid immiscibility should play an important role in the formation of cryolite. Cryolite is thought to be able to serve as a reference mineral for rare metal-rare earth mineralization in granites with high lithium and fluorine content.

Nickel isotope ratios trace the process of sulfide-silicate liquid immiscibility during magmatic differentiation

Sulfide-silicate liquid immiscibility (i.e., the coexistence of two liquid phases in equilibrium) plays a significant role in the processes of planetary-scale differentiation, the formation of Earth’s crust, and the genesis of magmatic sulfide ore deposits. The stable isotope geochemistry of nickel can potentially take advantage of fractionation signals produced in magmatic systems where immiscible sulfide and silicate liquid have equilibrated. Variations in Ni isotope ratio beyond those found in sulfide-undersaturated basaltic rocks can provide a hallmark of fractionation processes that control chalcophile and siderophile element abundances. We report high-precision Ni isotope ratio data for a stratigraphically-controlled sequence of Siberian Trap basalts in a volcanic edifice centered over the world’s largest concentration of magmatic sulfide ore deposits at Noril’sk-Talnakh, Russia. Nickel isotope ratios (δ60Ni (‰) = [(60Ni/58Ni)sample/(60Ni/58Ni)SRM986-1] × 1000) in the basaltic rocks range from +0.07 ± 0.02‰ to +1.00 ± 0.04‰ and correlate negatively with Ni and precious metal abundance levels, indicating extensive Ni isotope fractionation due to sulfide saturation of the silicate magma. A Rayleigh fractionation model fits the observed results and enables a precise estimate of the fractionation factor (α) between sulfide liquid and silicate melt to be 0.99965 (i.e., 103*lnα = −0.35). Our study illustrates the application of Ni isotope ratio data in understanding sulfide-silicate liquid immiscibility and the broader implications with respect to the formation of the largest known magmatic sulfide ore deposits in association with the Siberian Trap.

Neuropathic Symptoms in Parkinson’s Disease (P7-11.011)

<h3>Objective:</h3> To evaluate the prevalence of neuropathic symptoms in Parkinson9s disease (PD). <h3>Background:</h3> Peripheral neuropathy is seen in 4.8%–55% of Parkinson9s patients presenting predominantly as small fiber neuropathy with pain, paresthesia, and dysautonomia, and shares some overlapping features with PD. Use of levodopa and other comorbidities are common associated causes. Recent studies have found alpha synuclein deposition in skin biopsies of PD patients with autonomic dysfunction, but its association with peripheral neuropathy is uncertain. The co-occurence of both diseases leads to increased disability. <h3>Design/Methods:</h3> We conducted a retrospective study of 84 patients with PD followed at the UConn Health Neurology Clinic during 2020. Demographics, presence and duration of neuropathic symptoms since PD diagnosis, and other common causes of neuropathy were analyzed. <h3>Results:</h3> Neuropathic symptoms were detected in 41% (n=35) of PD cases, including tingling of lower extremities (15%), numbness of lower extremities (26%), dry eyes/mouth (25%), diaphoresis (8%), constipation (77%), and pre-syncope/syncope (29%). On average, patients reported neuropathic symptoms 25.5 months following PD diagnosis and 28% (n=10) had preceding symptoms, an average of 19 months prior to PD diagnosis. 46% (n=16) had a documented history of neuropathy but only 23% (n=8) underwent formal work up with EMG. None had skin biopsy. Alcohol use (p=0.194), thyroid disease (p= 0.236), use of levodopa (p=0.469), and diabetes (p=0.570) showed no significant correlation with the presence of neuropathic symptoms. <h3>Conclusions:</h3> Our cohort showed similar prevalence of neuropathic symptoms as in prior studies, and confirms that routine neuropathic evaluation may be warranted. Additionally, inspection for alpha synuclein deposits in association with fiber density analysis in skin biopsies might elucidate the association of both diseases and improve patient care. <b>Disclosure:</b> Miss Ganugapati has nothing to disclose. Dr. Costello has nothing to disclose. The institution of Dr. Prakash has received research support from UCB Biosciences Inc.. The institution of Dr. Prakash has received research support from Parkinson Foundation. Dr. Imperioli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenix. Dr. Imperioli has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ultragenyx Pharmaceuticals . Dr. Imperioli has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Law offices of Scott Doody. An immediate family member of Dr. Wajnsztajn has received personal compensation for serving as an employee of Alexion Pharmaceuticals.

Human placental proteomics and exon variant studies link AAT/SERPINA1 with spontaneous preterm birth

BackgroundPreterm birth is defined as live birth before 37 completed weeks of pregnancy, and it is a major problem worldwide. The molecular mechanisms that lead to onset of spontaneous preterm birth are incompletely understood. Prediction and evaluation of the risk of preterm birth is challenging as there is a lack of accurate biomarkers. In this study, our aim was to identify placental proteins that associate with spontaneous preterm birth.MethodsWe analyzed the proteomes from placentas to identify proteins that associate with both gestational age and spontaneous labor. Next, rare and potentially damaging gene variants of the identified protein candidates were sought for from our whole exome sequencing data. Further experiments we performed on placental samples and placenta-associated cells to explore the location and function of the spontaneous preterm labor-associated proteins in placentas.ResultsExome sequencing data revealed rare damaging variants in SERPINA1 in families with recurrent spontaneous preterm deliveries. Protein and mRNA levels of alpha-1 antitrypsin/SERPINA1 from the maternal side of the placenta were downregulated in spontaneous preterm births. Alpha-1 antitrypsin was expressed by villous trophoblasts in the placenta, and immunoelectron microscopy showed localization in decidual fibrinoid deposits in association with specific extracellular proteins. siRNA knockdown in trophoblast-derived HTR8/SVneo cells revealed that SERPINA1 had a marked effect on regulation of the actin cytoskeleton pathway, Slit–Robo signaling, and extracellular matrix organization.ConclusionsAlpha-1 antitrypsin is a protease inhibitor. We propose that loss of the protease inhibition effects of alpha-1 antitrypsin renders structures critical to maintaining pregnancy susceptible to proteases and inflammatory activation. This may lead to spontaneous premature birth.

Tracing electron density changes in langbeinite under pressure.

Pressure is well known to dramatically alter physical properties and chemical behaviour of materials, much of which is due to the changes in chemical bonding that accompany compression. Though it is relatively easy to comprehend this correlation in the discontinuous compression regime, where phase transformations take place, understanding of the more subtle continuous compression effects is a far greater challenge, requiring insight into the finest details of electron density redistribution. In this study, a detailed examination of quantitative electron density redistribution in the mineral langbeinite was conducted at high pressure. Langbeinite is a potassium magnesium sulfate mineral with the chemical formula [K2Mg2(SO4)3], and crystallizes in the isometric tetartoidal (cubic) system. The mineral is an ore of potassium, occurs in marine evaporite deposits in association with carnallite, halite and sylvite, and gives its name to the langbeinites, a family of substances with the same cubic structure, a tetrahedral anion, and large and small cations. Single-crystal X-ray diffraction data for langbeinite have been collected at ambient pressure and at 1 GPa using a combination of in-house and synchrotron techniques. Experiments were complemented by theoretical calculations within the pressure range up to 40 GPa. On the basis of changes in structural and thermal parameters, all ions in the langbeinite structure can be grouped into 'soft' (potassium cations and oxygens) and 'hard' (sulfur and magnesium). This analysis emphasizes the importance of atomic basins as a convenient tool to analyse the redistribution of electron density under external stimuli such as pressure or temperature. Gradual reduction of completeness of experimental data accompanying compression did not significantly reduce the quality of structural, electronic and thermal parameters obtained in experimental quantitative charge density analysis.

Introduction and characterization of Neogene volcanic eruptions in the Parizarea (Kerman province) and their petrological features using pyroclastic deposits

In the Pariz area, (Kerman province), there are special deposits and in the geological maps, they have introduced as detrital unconsolidated Neogene Conglomerates (Ng). Detailed field observations of these deposits in this study showed that they are pyroclastic deposits from the post Eocene unknown explosive eruptions. Stratigraphically, these units overlie the Eocene basaltic rocks, and their clasts are dacitic and rhyolitic in compositions, which means that they are completely different from the Eocene rocks. Genetically, these deposits are pyroclastic surges and flow deposits in association with the laharic units. Lithological features of these pyroclastics along with the absence of ducite or rhyolite lava flows and the relatively large dispersion of these deposits indicate that they have been formed by water bearing explosive eruptions. The clasts of these pyroclastic deposits contain plagioclase, amphibole, biotite and quartz and they are geochemically belong to the calcalkaline magmatic series. The geochemical characteristics of these rocks show that they formed in a post-collision environment and their geochemical nature are similar to the continental magmatic arc associations. These results are consistent with other studies on the post Eocene magmatic rocks of the Dehaj-Sardouieh belt.

Genetic environment of W skarn and Pb-Zn vein mineralization associated with the Imog granite in the Taebaeksan Mineralized District, South Korea

W skarn and Pb-Zn vein mineralization were developed in the Imog and Seojin deposits in association with the Imog granite that intruded the Cambro-Ordovician carbonate rocks in the Taebaeksan Mineralized District, South Korea. Garnet/Pyroxene ratios in the skarn of both deposits decreased as away from the granite. In the Imog deposit, garnet compositions vary from andradite to grossular series with increasing distance from the igneous contact. However, andradite is dominant in the Seojin deposit. In both the deposits, diopside series remained dominant with a slight increase in johannsenite composition in late stage. The skarn ore minerals mainly comprise scheelite and pyrrhotite, whereas the vein ores comprise galena, sphalerite, and arsenopyrite. In sphalerite, a decrease in the CdS contents and an increase in the MnS contents from W skarn to Pb-Zn vein ore can be attributed to leaching from sedimentary rocks and high mobility in magmatic-hydrothermal fluids, respectively. The δ34SH2S values of sulfide minerals were 3.3–4.9‰ for W skarn and 4.1–6.7‰ for Pb-Zn vein ore in the Imog deposit, mostly belonging to magmatic origin, but a slight increase is observed in the vein stage due to the interaction with carbonate host rock. The isotopic depletion of δ18O and δ13C values from host rock to skarn and Pb-Zn vein can be mostly attributed to the infiltration of external fluids involving magmatic components. The effects of organic carbon in the host rock and input of meteoric water resulted in distinctly low δ13C and δ18O values in the skarn and vein samples, respectively. The sulfur isotope geothermometer and mineral stability in combination with fluid inclusion data constrained the upper limit of skarn formation to 520 °C and 3 kbar and a temperature range of <360–460 °C and >0.5 kbar for W and Pb-Zn mineralization in the Imog deposit, but pressure would be higher in the Seojin deposit. The skarn was formed by the intrusion of oxidized magma, and scheelite mineralization occurred with decreasing oxygen fugacity. The Pb-Zn vein ores were precipitated with decreasing sulfur fugacity and increasing pH under the influence of meteoric water and carbonate host rock.

Cu3(As,Sb)S4 minerals from the Baia Mare metallogenic district, Eastern Carpathians, Romania – a case study from the Cisma ore deposit

The occurrence of Cu 3 (As,Sb)S 4 minerals, i.e. the enargite and luzonite-famatinite series, is poorly known in the Neogene Baia Mare metallogenic district, NW Romania, with few records and no analytical data. This study provides the first EPMA and XRD data on enargite/luzonite from the Baia Mare metallogenic district, i.e. the Cisma ore deposit from the Baiuţ metallogenic field, and the Herja ore deposit. Vein-type ore bodies bearing Cu 3 (As,Sb)S 4 minerals from Cisma are hosted by Paleocene–Eocene flysch successions, while the host rock of the enargite-bearing ore from Herja is unknown. The enargite and luzonite-famatinite series are known as “exotic” in low sulphidation epithermal ore deposits, “typical” in high sulphidation epithermal deposits in association with tennantite, and “sometimes common” in small amounts in intermediate sulphidation epithermal ore deposits. The occurrence of enargite/luzonite in the Baia Mare district suggests the need to update the metallogenic interpretation for several ore deposits, partly at the district scale in relation to other ore deposit/mineralogy features, e.g. vuggy silica, hypogene argillic alteration.

Bone retouchers and technological continuity in the Middle Stone Age of North Africa.

Evidence for specialised bone tools has recently been reported for the Middle Stone Age of North Africa [one], which complements similar finds of slightly younger age in South Africa [two, three]. However, until now scant reference has been made to lesser known tools also made of bone (‘bone retouchers’) that were employed specifically as intermediaries for working or refining stone artefacts, that are sometimes present in these assemblages. In this paper we describe 20 bone retouchers from the cave of Grotte des Pigeons at Taforalt in north-east Morocco. This is the largest stratified assemblage of bone retouchers from a North African MSA site, and the biggest single collection so far from the African Continent. A total of 18 bone retouchers was recovered in securely dated archaeological levels spanning a period from ~ 84.5 ka to 24 ka cal BP. A further two bone retouchers were found in a layer at the base of the deposits in association with Aterian artefacts dating to around 85,000 BP and so far represent the earliest evidence of this type of tool at Taforalt. In this paper we present a first, detailed description of the finds and trace the stages of their production, use and discard (chaîne opératoire). At the same time, we assess if there were diachronic changes in their form and function and, finally, explore their presence in relation to stone tools from the same occupation layers of the cave.

Carbon stable isotope patterns of cyclic terpenoids: A comparison of cultured alkaliphilic aerobic methanotrophic bacteria and methane-seep environments

Aerobic methanotrophic bacteria are known to synthesize a variety of cyclic terpenoids which are typified by 13C-depleted, methane-derived carbon. This peculiarity facilitates identification of methanotroph biomarkers in natural samples. However, the current biomarker database does not always allow biomarker patterns of marine samples to be assigned to the different types of aerobic methanotrophs. To overcome this shortcoming, the carbon stable isotope composition of cyclic terpenoids of two strains of the Type I methanotroph genus Methylomicrobium was analyzed. Other than aerobic methanotrophs used for biomarker studies in the past, these two strains deriving from soda lake environments are able to tolerate the conditions typifying marine environments including high alkalinity and salinity. The cyclic terpenoid inventory of the two strains comprises 4-methyl steroids, 3-methyl- and desmethyl bacteriohopanepolyols (aminotetrol and aminotriol), and tetrahymanol, all of which are 13C-depleted. The average carbon isotope fractionation between methane and the respective lipid (Δδ13Cterpenoid-methane) is found to be −25‰ for M. kenyense and −16‰ for M. alcaliphilum. These data shed new light on the previously reported compound and carbon stable isotope patterns of cyclic terpenoids from methane-seep environments. Particularly, 13C-depleted tetrahymanol and gammacerane are reinterpreted as biomarkers of aerobic methanotrophic bacteria based on their occurrence in methane-seep deposits in association with other biomarkers of aerobic methanotrophs. The use of δ13C values of anaerobic methane-oxidizing archaea (ANME) lipids for the reconstruction of the isotopic composition of parent methane allows us to calculate the Δδ13Cterpenoid-methane even for ancient seep environments. With this calculation, Type I and Type II methanotrophs can be discriminated, representing a new approach to better characterize past methanotrophy at seeps and possibly other marine environments.

Correlation Between Serological Makers and Immunofluorescence Deposits i n Kidney Tissue of Patients with Lupus Nephritis

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease. Few biomarkers for SLE have been validated and widely accepted for the laboratory follow-up of inflammatory activity. In SLE patients, with lupus nephritis (LN), complement activation leads to fluctuation of serum C3 and C4 that are frequently used as clinicalm biomarker of disease activity in SLE. Patients and Methods: In this study the number of patients were 37, seven patients were excluded for incomplete data collection, 28 were females ,2 were males. The duration of the study is two years from 2015 to 2017. Patients were considered to have SLE and LN according to American College of Rheumatology (ACR) criteria, and International Society of Nephrology/ Renal Pathology Society (ISN/RPS). All patients were evaluated withm clinical presentation, laboratory investigations. Our patients underwent kidney biopsy according to standard procedure by Kerstin Amann, and their tissue specimens were studied in the laboratory with light microscope (LM) and immunofluorescence microscope reagents. The relationship between the serological markers and immunofluorescence deposits in kidney biopsy of all patients were studied using the statistical analysis of Pearson correlation and single table student's T test. A P value 0.05 was considered statistically significant. Results: The granular pattern of IF deposits was present in all LN patients, and in more than two third of patients these IF deposits presented in glomerular, tubular, and mesangium sites. While less than one third of patients had IF deposits in the mesangium only. There was no statistically significant correlation between serum ANA, anti-dsDNA, and IF deposits of different types. There was significant correlation between serum C3 and C4 hypocomplementemia and IgG immune deposits in kidney biopsy, and there was significant relationship between serum C3 hypocomplementemia and full house immunofluorescence (FHIF) deposits inm kidney biopsy.Conclusions:Immunofluorescence deposits is mainly granular pattern in LN patients. There was no significant association between serum ANA, anti-dsDNA, and immune deposits in kidney tissue. Immunofluorescence deposits of IgG type correlates significantly with serum C3 and C4 hypocomplemetemia, and these immune deposits in association with low complement levels correlates with LN flare. There was significant correlation between C3 hypocomplementemia and FHIF.

The origin and internal structures of submarine-slide deposits in a lower Pleistocene outer-fan succession in the Kazusa forearc basin on the Boso Peninsula of Japan

This study investigates the internal geometry and formation processes of submarine-slide deposits in a lower Pleistocene outer-fan succession in the Kazusa forearc basin on the Boso Peninsula of Japan. The submarine-slide deposits are ~40m thick, with a minimum length of ~900m and a width of ~700m. Both the submarine-slide deposits and host deposits comprise siltstones intercalated with very thin- to medium-bedded, sheet-like turbidites and volcanic ash beds. Based on the sequence-stratigraphic framework of the submarine-fan succession, we conclude that the submarine-slide deposits formed during a glacioeustatic sea-level lowstand at about 1.16Ma.The submarine-slide deposits are characterized by thrust sequences with a ramp anticline in the frontal part. A basal slide plane in the lower part of the deposits is developed at a horizon located 2–4cm below the base of a coarse volcanic ash bed and is associated with sheared deposits. Slide planes are sealed in the upper part of the submarine-slide deposits in association with drag folds and chaotic deposits. Finally, the submarine-slide deposits are transitionally overlain by ~3-m-thick chaotic muddy deposits, and are finally overlain by siltstones intercalated with very thin- to medium-bedded, sheet-like turbidites and volcanic ash beds, which show lithofacies features similar to those of the submarine-slide deposits. The variations in the deformation styles indicate that sliding occurred as a synsedimentary process in the outer-fan environment, and the basal slide plane formed when the porosity of the muddy deposits was reduced to ~55% or less.Based on the empirical relationship between the submarine-fan length and lower-fan slopes from modern examples, the gradient of the outer-fan is estimated at 0.31°–0.46°, which is lower than the threshold gradient of 1.2° for a 40-m-thick submarine slide with the estimated basal porosity. Based on the distribution of deformed deposits within the lower-fan host deposits, the minimum volume and runout distance of the submarine-slide deposits are estimated to be ~3×107m3 and ~5km, respectively. Furthermore, based on data from modern submarine slides, the elevation difference between the failed mass in both the starting and depositional areas is estimated to be 80–170m. Thus, the initiation of a submarine slide in the outer-fan environment was likely influenced by a combination of external forces, such as seismic shaking and increased pore-water pressure in association with the seepage of gas and water from underlying deposits in the Kazusa forearc basin. This study suggests that submarine slides occur in distal and low-gradient deep-water environments in active-margin basins.

Modeling 3D crustal structure in Lachlan Orogen, Victoria, Australia: Implications for gold deposition

We use numerical simulations to identify sites of dilation and areas of high, shear strain and fluid flow that may be related to gold deposition in faults that transect the western sub-province of the Lachlan Orogen. Our results can explain how a late tectonic history consisting of a switch from east–west compression to north–south transpression contributes to the formation of gold deposits in association with late fault movements. The models simulate incremental east–west shortenings of 4% and a superimposed 1% north–south shortening on major crustal-scale (intrazonal) faults and suggest that strain and fluid flow was greatest in the shallow-dipping fault segments (first order faults) that lie within the mafic rocks of the lower crust. The areas above the shallow-dipping segments of intrazonal faults (second order) become sites for the initiation of later (third-order) faults and fracture networks, within the higher-level metasedimentary rocks, strain decreases in the steeper segments of the intrazonal faults. These second-order faults are inferred to act as highly permeable channel-ways for fluid discharge and it is their geometry and a shift from east–west reverse-dip-slip to north–south reverse-oblique-slip fault kinematics that controls the final distribution of gold mineralization in the folded metasedimentary rocks. Changing the direction of principle compression, has a dramatic effect on the extent and location of volumetric strain (dilation) and fluid flow with localized deformation within bedding-parallel veins dispersing fluid flow. Increased dilation facilitates the influx of gold-bearing fluids that in combination with a fault–fracture network, and geochemical factors, have led to significant amounts of localized gold mineralization.

A new type of micro-disseminated gold deposits in association with diabase found in Yunnan and Guizhou provinces and Guangxi Zhuang Autonomous Region—Their geological characteristics and metallogenic conditions

With the continuous development of gold ore prospecting and exploration in recent years a new type of micro-disseminated gold deposits have been found in the regions of Southwest Guizhou Province and Northwest Guangxi Zhuang Autonomous Region, with the orebodies directly occurring in diabase or in the contact zone between diabase and strata. The orebodies are strictly controlled by fault structures. The discovery of this type of gold deposits has brought about new prospects for gold ore prospecting in the Yunnan-Guizhou-Guangxi Golden Triangle region. From the preliminary analysis of the geological characteristics of the Qiaoxiang gold deposit in Wangmo County, in combination with the results of research work in the adjacent areas in recent years, this paper roughly described the geological characteristics and metallogenic conditions of this type of gold ore deposits with an attempt to make more and more geologists pay enough attention to this type of gold ore deposits, so as to promote gold ore prospecting in Guizhou Province to develop toward a variety of types of gold deposits in all round way.

Temporal variations in channel patterns and facies architecture in a gravelly fluvial system: The Paleogene Iwaki Formation on the Joban Coalfield, a forearc basin in Northeast Japan

AbstractThis paper examined sequence‐stratigraphic features of a gravelly fluvial system of the Iwaki Formation, which developed in a forearc‐basin setting in Northeast Japan during the Eocene through Oligocene. On the basis of three‐dimensional architectural element analysis, we discriminated three major cycles of channel complexes, which contain ten component channel deposits in total in the fluvial succession. Component channel deposits in the uppermost part of each cycle are sandier and associated with overbank muddy deposits and coal beds as compared with those in the lower part of the cycle. Mean clast‐size also decreases upsection in the entire gravelly fluvial deposits. The fluvial succession is interpreted to have been deposited in response to an overall rise in relative sea level that was superimposed by three short‐term relative sea‐level rises on the basis of vertical stacking patterns and component lithofacies features of channel deposits, and of correlation of the fluvial succession with an age‐equivalent marine succession in an area about 50 km offshore. However, geometry and stacking patterns of the channel complexes do not exhibit any distinct temporal variation and amalgamated channel and bar deposits are dominant throughout the transgressive fluvial succession. On the other hand, an overall fining‐upward pattern of the entire Iwaki Formation fluvial deposits in association with three component fining‐upward patterns is distinct, and is interpreted to be consistent with the tenet of the standard fluvial sequence‐stratigraphic models. This indicates that the present example represents one type of variation in the standard fluvial sequence‐stratigraphic models, possibly reflecting the forearc‐basin setting, which is generally represented by higher valley slope, higher shedding of coarse‐grained sediments, and shorter longitudinal profiles to the coastal area as compared with a passive‐continental‐margin setting.

IgA-dominant postinfectious glomerulonephritis: a report of 13 cases with common ultrastructural features

A unique form of postinfectious glomerulonephritis characterized by IgA-dominant immune complex deposits was recently described by Nasr et al (Hum Pathol. 2003;34:1235-1241), each case after a Staphylococcus infection in diabetic patients. Others have described glomerulonephritis with IgA-containing immune complex deposits in association with staphylococcal infections, although their histology was more varied and electron microscopy often did not to show large subepithelial deposits ("humps") typical of postinfectious glomerulonephritis. In this report, we describe demographic, clinical, and renal biopsy findings in 13 cases of IgA-dominant postinfectious glomerulonephritis, each characterized by subepithelial humps at various stages of resolution. All patients presented with renal insufficiency (mean serum creatinine +/- SD, 4.4 +/- 2.7 mg/dL), hematuria (macroscopic in 3), and proteinuria (nephrotic range in 6). Based on histology and electron microscopy, postinfectious glomerulonephritis was classified as acute in 2 patients, subacute in 3, and resolving/persistent in 8. There were 6 patients who had recent Staphylococcus aureus infections (3 methicillin resistant), 5 who were diabetic, and 3 with nephropathy. A total of 4 patients (3 with serum creatinine >8.0 mg/dL at biopsy) developed end-stage renal disease, whereas 9 had a mean serum creatinine of 2.0 +/- 1.1 mg/dL (range, 0.8-4.4) at 10 +/- 13 months (range, 2-44) after biopsy. In summary, IgA-dominant postinfectious glomerulonephritis resembles poststreptococcal glomerulonephritis in its histologic spectrum and electron microscopy findings, is often associated with staphylococcal infections, occurs in diabetics and nondiabetics, and may resolve if renal failure at presentation is not severe.

Case Reports of a New Syndrome Associating Gingival Fibromatosis and Dental Abnormalities in a Consanguineous Family

Gingival fibromatosis (GF) is characterized by fibrotic enlargement of the gingiva that can be inherited as an isolated trait (named hereditary gingival fibromatosis) or as a component of a syndrome. This article reports one kindred affected by a syndrome characterized by GF associated with dental abnormalities (DA) including generalized thin hypoplastic amelogenesis imperfecta (AI). To characterize the pattern of inheritance and the clinical features, 70 family members were examined. Hematoxylin and eosin staining, immunohistochemistry, and scanning electronic microscopy (SEM) were performed to identify the alterations on gingiva, teeth, and dental follicles. Examination of the family pedigree demonstrated multiple consanguineous first-cousin marriages and an autosomal recessive trait of inheritance. Four members demonstrated mild GF in association with DA, including generalized thin hypoplastic AI, intrapulpal calcifications, delay of tooth eruption, and pericoronal radiolucencies involving unerupted teeth. One of those four patients also had mental retardation (MR). MR as an isolated feature was observed in six members, whereas isolated GF was found in one individual. A combination of gingivectomy and gingivoplasty followed by regular dental procedures were performed in these patients. Histologic examination of the gingival enlargement revealed a dense connective tissue containing myofibroblasts, islands of odontogenic epithelium, and calcified psammomatous deposits, which resembled cementicle-like structures by SEM. Pericoronal lesions also showed calcified psammomatous deposits in association with islands of odontogenic epithelium. Enamel ultrastructure analysis revealed normal surface alternating with irregular and porous areas. To the best of our knowledge, these cases represent a new syndrome within the spectrum of those including GF.

SIMS imaging of gadolinium isotopes in tissue from Nephrogenic Systemic Fibrosis patients: Release of free Gd from magnetic resonance imaging (MRI) contrast agents

Recently, Gd-based magnetic resonance imaging (MRI) contrast agents (GBMCA) have been linked to a new disease, Nephrogenic Systemic Fibrosis (NSF), with skin and systemic toxicity and death in certain patients with renal failure. Due to widespread use of GBMCA in diagnostic MRI, it is essential to study their excretion, metabolism, and target sites in cells and tissues. A CAMECA IMS-3f SIMS ion microscope and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) were used for imaging Gd isotopes in relation to calcium distributions in histologic sections of human tissues. SIMS imaging revealed two types of Gd localization in skin biopsies of patients who received GBMCA. The Gd was present in micrometer size deposits in association with calcium, and in detectable amounts in a more diffuse cellular distribution. Only the Gd-containing deposits associated with Ca and P were detectable using SEM/EDS. As only insoluble deposits remain in the biopsy tissues after aqueous and organic solvent processing of the tissue, our observations support release of free Gd from the GBMCA and selective localization of insoluble Gd in the target tissue from patients with NSF. This study opens new novel applications of SIMS for characterization of the safety of GBMCA.

Tubular Basement Membrane Immune Deposits in Association with BK Polyomavirus Nephropathy

Tubular basement membrane immune deposits (TBMID) are rare in renal allografts and usually have been found in association with immune complex mediated glomerular injury. We report an association between TBMID and BK polyomavirus nephropathy (BKN). We reviewed clinical data and results of allograft biopsies of 30 patients with BKN (16 with and 14 without TBMID). TBMID were detected by immunofluorescence or electron microscopy. Initial and follow-up biopsies were assessed for degree of interstitial inflammation and fibrosis and severity of viral infection, and were correlated with patients' clinical data. Biopsies initially diagnostic for BKN with TBMID, compared to BKN biopsies without deposits, demonstrated more severe interstitial inflammation and fibrosis, and greater numbers of virally infected cells. Similar findings were present in follow-up biopsies. Utilizing three different antibodies directed against viral epitopes, viral antigens could not be detected within TBMID. Thirty percent of patients with TBMID and 70% without deposits had follow-up biopsies, in which virus could not be detected immunohistochemically. Treatment for all included decreasing immunosuppression, cidofovir and/or leflunomide. Clinical data correlated well with histological findings. We conclude that a significant proportion of patients with BKN show TBMID on kidney biopsy. The prognostic significance of this finding remains to be elucidated.

An outcrop gamma ray study of the Tumblagooda Sandstone, Western Australia

Outcrop of the Tumblagooda Sandstone, Western Australia, is used to demonstrate the internal heterogeneity in ancient fluvial and deltaic systems and the potential difficulties for correlation and prediction of sandbody geometry in the subsurface. Twenty-two gamma ray (GR) logs were measured from a 50 m × 6.5 km coastal section in three facies associations (A–C) interpreted as braided river, overbank/interdistributary and distributary channel to distributary mouth deposits, respectively. Five informal units are identified with the aid of the GR logs: Units 1–3 are braided river sandstones of Association A; Unit 4 overbank/interdistributary deposits of Association B (subdivided into 4a–4c); and Unit 5 is dominated by distributary channel sandstones of Association C. The GR log profiles for the braided river deposits are smooth to ratty and highly variable in shape. Classic cylinder and bell profiles are present, as are funnel shapes. Lateral correlation based upon log character was impossible in Unit 1 (about 15 m thickness), even over short distances (i.e. 50 m). Despite layer-cake bedding, correlation was only possible in Units 2–3 (approx. 5 m thickness) by the field mapping of several sandstone benches and a regional pebbly marker (Gabba Gabba Member). Correlation for more than a kilometre based upon the log shape and lithology appears futile. The GR log profile for the overbank/interdistributary deposits of Unit 4 resolves the metre to sub-metre scale interbeds of very-fine grained and coarser grained sandstones. These form sheet sand bodies that stack together as broadly coarsening-upward cycles, the GR character of which allows lateral correlation for a few hundred metres. These deposits occur at the same stratigraphic height as a distributary channel system to the south, which is approximately 2.5 km wide and belongs to Unit 5. Unit 5 is composed of vertically stacked distributary channel sands and sheet-like sands that may represent distributary mouths. The channel systems were probably confined by sandy levees. The distributary channel systems and associated deposits are burrowed by Skolithos and have low total counts. However, stratigraphic correlation of these sand bodies was difficult due to discontinuous exposures. Nevertheless, several intensely bioturbated horizons appear to be traceable within Unit 5 and probably represent temporary delta abandonment and flooding. These findings imply that in reservoir modelling of similar deposits caution must be taken not to over-interpret sedimentological models based upon well log character, especially on a limited data set. Stratigraphic correlation based upon sedimentary logs and GR is extremely difficult in the field and could be highly problematic in the subsurface, even in layer cake systems. However, contrary to first impressions, the inability to correlate between subsurface wells may in fact be a clue to a multi-storey, multi-lateral, braided river system. The internal heterogeneity described here is below the resolution of conventional well log data (approx. 30 cm), but resolvable on image log and core data. Deciphering the appropriate analogue data and semi-variograms to model and upscale the internal heterogeneity (of this outcrop and similar deposits) in three dimensions is a significant challenge.