Exploration of fs-laser ablation parameter space for 2D/3D imaging of soft and hard materials by tri-beam microscopy

Tri-beam microscopes comprising a fs-laser beam, a Xe+ plasma focused ion beam (PFIB) and an electron beam all in one chamber open up exciting opportunities for site-specific correlative microscopy. They offer the possibility of rapid ablation and material removal by fs-laser, subsequent polishing by Xe-PFIB milling and electron imaging of the same area. While tri-beam systems are capable of probing large (mm) volumes providing high resolution microscopical characterisation of 2D and 3D images across exceptionally wide range of materials and biomaterials applications, presenting high quality/low damage surfaces to the electron beam can present a significant challenge, especially given the large parameter space for optimisation. Here the optimal conditions and artefacts associated with large scale volume milling, mini test piece manufacture, serial sectioning and surface polishing are investigated, both in terms of surface roughness and surface quality for metallic, ceramic, mixed complex phase, carbonaceous, and biological materials. This provides a good starting place for those wishing to examine large areas or volumes by tri-beam microscopy across a range of materials.

Human cardiovascular disease model predicts xanthine oxidase inhibitor cardiovascular risk

Some health concerns are often not identified until late into clinical development of drugs, which can place participants and patients at significant risk. For example, the United States Food and Drug Administration (FDA) labeled the xanthine oxidase inhibitor febuxostat with a"boxed" warning regarding an increased risk of cardiovascular death, and this safety risk was only identified during Phase 3b clinical trials after its approval. Thus, better preclinical assessment of drug efficacy and safety are needed to accurately evaluate candidate drug risk earlier in discovery and development. This study explored whether an in vitro vascular model incorporating human vascular cells and hemodynamics could be used to differentiate the potential cardiovascular risk associated with molecules that have similar on-target mechanisms of action. We compared the transcriptomic responses induced by febuxostat and other xanthine oxidase inhibitors to a database of 111 different compounds profiled in the human vascular model. Of the 111 compounds in the database, 107 are clinical-stage and 33 are FDA-labelled for increased cardiovascular risk. Febuxostat induces pathway-level regulation that has high similarity to the set of drugs FDA-labelled for increased cardiovascular risk. These results were replicated with a febuxostat analog, but not another structurally distinct xanthine oxidase inhibitor that does not confer cardiovascular risk. Together, these data suggest that the FDA warning for febuxostat stems from the chemical structure of the medication itself, rather than the target, xanthine oxidase. Importantly, these data indicate that cardiovascular risk can be evaluated in this in vitro human vascular model, which may facilitate understanding the drug candidate safety profile earlier in discovery and development.

Ketohexokinase inhibition improves NASH by reducing fructose-induced steatosis and fibrogenesis

Background & Aims

Increasing evidence highlights dietary fructose as a major driver of non-alcoholic fatty liver disease (NAFLD) pathogenesis, the majority of which is cleared on first pass through the hepatic circulation by enzymatic phosphorylation to fructose-1-phosphate via the ketohexokinase (KHK) enzyme. Without a current approved therapy, disease management emphasises lifestyle interventions, but few patients adhere to such strategies. New targeted therapies are urgently required.

Methods

We have used a unique combination of human liver specimens, a murine dietary model of NAFLD and human multicellular co-culture systems to understand the hepatocellular consequences of fructose administration. We have also performed a detailed nuclear magnetic resonance-based metabolic tracing of the fate of isotopically labelled fructose upon administration to the human liver.

Results

Expression of KHK isoforms is found in multiple human hepatic cell types, although hepatocyte expression predominates. KHK knockout mice show a reduction in serum transaminase, reduced steatosis and altered fibrogenic response on an Amylin diet. Human co-cultures exposed to fructose exhibit steatosis and activation of lipogenic and fibrogenic gene expression, which were reduced by pharmacological inhibition of KHK activity. Analysis of human livers exposed to ¹³C-labelled fructose confirmed that steatosis, and associated effects, resulted from the accumulation of lipogenic precursors (such as glycerol) and enhanced glycolytic activity. All of these were dose-dependently reduced by administration of a KHK inhibitor.

Conclusions

We have provided preclinical evidence using human livers to support the use of KHK inhibition to improve steatosis, fibrosis, and inflammation in the context of NAFLD.

Lay summary

We have used a mouse model, human cells, and liver tissue to test how exposure to fructose can cause the liver to store excess fat and become damaged and scarred. We have then inhibited a key enzyme within the liver that is responsible for fructose metabolism. Our findings show that inhibition of fructose metabolism reduces liver injury and fibrosis in mouse and human livers and thus this may represent a potential route for treating patients with fatty liver disease in the future.

The ELFIN Mission

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93^∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (T_orbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E < 40% and a fluxgate magnetometer (FGM) on a ∼72 cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5 Hz Nyquist (nominally) with <0.3 nT/sqrt(Hz) noise at 1 Hz. The spinning satellites (T_spin ∼ 3 s) are equipped with magnetorquers (air coils) that permit spin-up or -down and reorientation maneuvers. Using those, the spin axis is placed normal to the orbit plane (nominally), allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250 keV - 5 MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018 and launched by the ELaNa XVIII program on a Delta II rocket (with IceSatII as the primary). Mission operations are currently funded by NASA. Working under experienced UCLA mentors, with advice from The Aerospace Corporation and NASA personnel, more than 250 undergraduates have matured the ELFIN implementation strategy; developed the instruments, satellite, and ground systems and operate the two satellites. ELFIN's already high potential for cutting-edge science return is compounded by concurrent equatorial Heliophysics missions (THEMIS, Arase, Van Allen Probes, MMS) and ground stations. ELFIN's integrated data analysis approach, rapid dissemination strategies via the SPace Environment Data Analysis System (SPEDAS), and data coordination with the Heliophysics/Geospace System Observatory (H/GSO) optimize science yield, enabling the widest community benefits. Several storm-time events have already been captured and are presented herein to demonstrate ELFIN's data analysis methods and potential. These form the basis of on-going studies to resolve the primary mission science objective. Broad energy precipitation events, precipitation bands, and microbursts, clearly seen both at dawn and dusk, extend from tens of keV to >1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.

Determination of Total Vitamin C in Fruit Juices and Related Products by Liquid Chromatography: Interlaboratory Study

A interlaboratory study was conducted to evaluate a liquid chromatographic (LC) procedure for the determination of total vitamin C in foods at levels of 5–60 mg/100 g. Emphasis was placed on fruit juices, although selected foods were also included in the study. Following dissolution of sample in water, endogenous dehydroascorbic acid was converted to ascorbic acid by precolumn reduction with dithiothreitol at neutral pH. Total ascorbate was determined by C18 reversed-phase LC with a phosphate eluent at pH 2.5, incorporating dithiothreitol to maintain vitamin C in the reduced form, and UV detection at 254 nm. Seven types of fruit juices and foods were tested by 19 collaborators in 7 countries. Three duplicate juices and foods met the criteria for Youden pairs and yielded repeatability relative standard deviation of 5.80–14.66%. Reproducibility relative standard deviation ranged from 6.36 to 35.54% (n = 10) with HORRAT values of 0.82–4.04. The LC method is suitable for routine use in fruit products and foods containing &gt;5 mg/100 g vitamin C and is recommended for further validation by AOAC INTERNATIONAL and International Fruit Juice Union.

Development of an in vitro human liver system for interrogating nonalcoholic steatohepatitis

A barrier to drug development for nonalcoholic steatohepatitis (NASH) is the absence of translational preclinical human-relevant systems. An in vitro liver model was engineered to incorporate hepatic sinusoidal flow, transport, and lipotoxic stress risk factors (glucose, insulin, free fatty acids) with cocultured primary human hepatocytes, hepatic stellate cells (HSCs), and macrophages. Transcriptomic, lipidomic, and functional endpoints were evaluated and compared with clinical data from NASH patient biopsies. The lipotoxic milieu promoted hepatocyte lipid accumulation (4-fold increase, P < 0.01) and a lipidomics signature similar to NASH biopsies. Hepatocyte glucose output increased with decreased insulin sensitivity. These changes were accompanied by increased inflammatory analyte secretion (e.g., IL-6, IL-8, alanine aminotransferase). Fibrogenic activation markers increased with lipotoxic conditions, including secreted TGF-β (>5-fold increase, P < 0.05), extracellular matrix gene expression, and HSC activation. Significant pathway correlation existed between this in vitro model and human biopsies. Consistent with clinical trial data, 0.5 μM obeticholic acid in this model promoted a healthy lipidomic signature, reduced inflammatory and fibrotic secreted factors, but also increased ApoB secretion, suggesting a potential adverse effect on lipoprotein metabolism. Lipotoxic stress activates similar biological signatures observed in NASH patients in this system, which may be relevant for interrogating novel therapeutic approaches to treat NASH.

Sequencing of mRNA identifies re-expression of fetal splice variants in cardiac hypertrophy

Cardiac hypertrophy has been well-characterized at the level of transcription. During cardiac hypertrophy, genes normally expressed primarily during fetal heart development are re-expressed, and this fetal gene program is believed to be a critical component of the hypertrophic process. Recently, alternative splicing of mRNA transcripts has been shown to be temporally regulated during heart development, leading us to consider whether fetal patterns of splicing also reappear during hypertrophy. We hypothesized that patterns of alternative splicing occurring during heart development are recapitulated during cardiac hypertrophy. Here we present a study of isoform expression during pressure-overload cardiac hypertrophy induced by 10 days of transverse aortic constriction (TAC) in rats and in developing fetal rat hearts compared to sham-operated adult rat hearts, using high-throughput sequencing of poly(A) tail mRNA. We find a striking degree of overlap between the isoforms expressed differentially in fetal and pressure-overloaded hearts compared to control: forty-four percent of the isoforms with significantly altered expression in TAC hearts are also expressed at significantly different levels in fetal hearts compared to control (P<0.001). The isoforms that are shared between hypertrophy and fetal heart development are significantly enriched for genes involved in cytoskeletal organization, RNA processing, developmental processes, and metabolic enzymes. Our data strongly support the concept that mRNA splicing patterns normally associated with heart development recur as part of the hypertrophic response to pressure overload. These findings suggest that cardiac hypertrophy shares post-transcriptional as well as transcriptional regulatory mechanisms with fetal heart development.

Global changes in gene expression during compatible and incompatible interactions of cowpea (Vigna unguiculata L.) with the root parasitic angiosperm Striga gesnerioides

BACKGROUND

Cowpea, Vigna unguiculata L. Walp., is one of the most important food and forage legumes in the semi-arid tropics. While most domesticated forms of cowpea are susceptible to the root parasitic weed Striga gesnerioides, several cultivars have been identified that show race-specific resistance. Cowpea cultivar B301 contains the RSG3-301 gene for resistance to S. gesnerioides race SG3, but is susceptible to race SG4z. When challenged by SG3, roots of cultivar B301 develop a strong resistance response characterized by a hypersensitive reaction and cell death at the site of parasite attachment. In contrast, no visible response occurs in B301 roots parasitized by SG4z.

RESULTS

Gene expression in the roots of the cowpea cultivar B301 during compatible (susceptible) and incompatible (resistant) interactions with S. gesnerioides races SG4z and SG3, respectively, were investigated at the early (6 days post-inoculation (dpi)) and late (13 dpi) stages of the resistance response using a Nimblegen custom design cowpea microarray. A total of 111 genes were differentially expressed in B301 roots at 6 dpi; this number increased to 2102 genes at 13 dpi. At 13 dpi, a total of 1944 genes were differentially expressed during compatible (susceptible) interactions of B301 with SG4z. Genes and pathways involved in signal transduction, programmed cell death and apoptosis, and defense response to biotic and abiotic stress were differentially expressed in the early resistance response; at the later time point, enrichment was primarily for defense-related gene expression, and genes encoding components of lignifications and secondary wall formation. In compatible interactions (B301-SG4z), multiple defense pathways were repressed, including those involved in lignin biosynthesis and secondary cell wall modifications, while cellular transport processes for nitrogen and sulfur were increased.

CONCLUSION

Distinct changes in global gene expression profiles occur in host roots following successful and unsuccessful attempted parasitism by Striga. Induction of specific defense related genes and pathways defines components of a unique resistance mechanism. Some genes and pathways up-regulated in the host resistance response to SG3 are repressed in the susceptible interactions, suggesting that the parasite is targeting specific components of the host's defense. These results add to our understanding of plant-parasite interactions and the evolution of resistance to parasitic weeds.

Abstract 266: MicroRNA Profiling Identifies Enrichment for Proteoglycan-Genes in Symptomatic Carotid Plaques

MicroRNAs are a class of small non-coding RNAs that regulate gene expression by binding to discrete sites of genes and inhibiting translation. The objective of this study was to identify microRNAs and downstream enriched targets associated with symptomatic carotid plaques. Carotid plaque samples from patients were defined as symptomatic if they were associated with a prior ischemic stroke or transient ischemic attack, or as asymptomatic if there were no prior ischemic events. Digital microRNA profiling was performed on the NanoString nCounter analysis system (NanoString Technologies, Seattle, WA) on carotid plaques from symptomatic (n=6) and asymptomatic (n=6) patients. We used the BioConductor/R package "edgeR" to perform moderated-ANOVA testing for differences in gene abundance between groups, assuming a negative binomial distribution of gene counts, with Benjamini-Hochberg multiple hypothesis correction to control false discovery rate. Analysis revealed five microRNAs that were significantly up-regulated in the symptomatic cohort (see Table 1) including miR-16, which was confirmed by RTqPCR (p=0.02). Predicted downstream targets of miR-16 were enriched for proteoglycan related genes including hyaluronan synthase 2, perlecan and betaglycan. Additionally, RTqPCR demonstrated up-regulation of CathepsinB transcript in symptomatic patients (n=46-50 per cohort, p=0.02) while CathepsinL and heparanase transcripts were not significantly different. CathepsinL enzyme activity was also not significantly different (n=46-50 per cohort). Taken together, these findings may reveal novel proteoglycan mediated signaling pathways, mediated through miR-16, regulating the progression of carotid plaque formation.

A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.

A pattern analysis of gene conversion literature

Gene conversion is an important biological process that involves the transfer of genetic (sequence) information from one gene to another. This can have a variety of effects on an organism, both short-term and long-term and both positive and detrimental. In an effort to better understand this process, we searched through over 3,000 abstracts that contain research on gene conversions, tagging the important data and performing an analysis on what we extract. Through this we established trends that give a better insight into gene conversion research and genetic research in general. Our results show the importance of the process and the importance of continuing gene conversion research.

Sexy gene conversions: locating gene conversions on the X-chromosome

Gene conversion can have a profound impact on both the short- and long-term evolution of genes and genomes. Here, we examined the gene families that are located on the X-chromosomes of human (Homo sapiens), chimpanzee (Pan troglodytes), mouse (Mus musculus) and rat (Rattus norvegicus) for evidence of gene conversion. We identified seven gene families (WD repeat protein family, Ferritin Heavy Chain family, RAS-related Protein RAB-40 family, Diphosphoinositol polyphosphate phosphohydrolase family, Transcription Elongation Factor A family, LDOC1-related family, Zinc Finger Protein ZIC, and GLI family) that show evidence of gene conversion. Through phylogenetic analyses and synteny evidence, we show that gene conversion has played an important role in the evolution of these gene families and that gene conversion has occurred independently in both primates and rodents. Comparing the results with those of two gene conversion prediction programs (GENECONV and Partimatrix), we found that both GENECONV and Partimatrix have very high false negative rates (i.e. failed to predict gene conversions), which leads to many undetected gene conversions. The combination of phylogenetic analyses with physical synteny evidence exhibits high resolution in the detection of gene conversions.

Housekeeping and tissue-specific genes differ in simple sequence repeats in the 5'-UTR region

SSRs (simple sequence repeats) have been shown to have a variety of effects on an organism. In this study, we compared SSRs in housekeeping and tissue-specific genes in human and mouse, in terms of SSR types and distributions in different regions including 5'-UTRs, introns, coding exons, 3'-UTRs, and upstream regions. Among all these regions, SSRs in the 5'-UTR show the most distinction between housekeeping genes and tissue-specific genes in both densities and repeat types. Specifically, SSR densities in 5'-UTRs in housekeeping genes are about 1.7 times higher than those in tissue-specific genes, in contrast to the 0.8-1.2 times differences between the two classes of genes in other regions. Tri-SSRs in 5'-UTRs of housekeeping genes are more GC rich than those of tissue-specific genes and CGG, the dominant type of tri-SSR in 5'-UTR, accounts for 74-79% of the tri-SSRs in housekeeping genes, as compared to 42-57% in tissue-specific genes. 75% of the tri-SSRs in the 5'-UTR of housekeeping genes have 4-5 repeat units, versus the 86-90% in tissue-specific genes. Taken together, our results suggest that SSRs may have an effect on gene expression and may play an important role in contributing to the different expression profiles between housekeeping and tissue-specific genes.

Distinct patterns of SSR distribution in the Arabidopsis thaliana and rice genomes

BACKGROUND

Simple sequence repeats (SSRs) in DNA have been traditionally thought of as functionally unimportant and have been studied mainly as genetic markers. A recent handful of studies have shown, however, that SSRs in different positions of a gene can play important roles in determining protein function, genetic development, and regulation of gene expression. We have performed a detailed comparative study of the distribution of SSRs in the sequenced genomes of Arabidopsis thaliana and rice.

RESULTS

SSRs in different genic regions - 5'untranslated region (UTR), 3'UTR, exon, and intron - show distinct patterns of distribution both within and between the two genomes. Especially notable is the much higher density of SSRs in 5'UTRs compared to the other regions and a strong affinity towards trinucleotide repeats in these regions for both rice and Arabidopsis. On a genomic level, mononucleotide repeats are the most prevalent type of SSRs in Arabidopsis and trinucleotide repeats are the most prevalent type in rice. Both plants have the same most common mononucleotide (A/T) and dinucleotide (AT and AG) repeats, but have little in common for the other types of repeats.

CONCLUSION

Our work provides insight into the evolution and distribution of SSRs in the two sequenced model plant genomes of monocots and dicots. Our analyses reveal that the distributions of SSRs appear highly non-random and vary a great deal in different regions of the genes in the genomes.

The evolution to stool DNA testing for colorectal cancer

Despite a variety of screening strategies and recent trends showing death rate stabilization, colorectal cancer still remains the second leading cause of overall cancer death. Current screening tools suffer from performance limitations, low patient acceptability, and marginal reliable access within the health care system. Noninvasive strategies present the lowest risk with the highest potential for patient satisfaction. However, serious implementation barriers exist requiring consistent programmatic screening, strict patient adherence, and poor sensitivity for adenomas. Colonoscopy remains an invasive screening test with the best sensitivity and specificity, but faces large financial costs, manpower requirements, patient access and adherence. Development of advanced molecular techniques identifying altered DNA markers in exfoliated colonocytes signify early or precancerous growth. Stool-based DNA testing provides an entirely noninvasive population-based screening strategy which patients can perform easier than faecal occult blood testing (FOBT). Large-scale prospective randomized control trials currently pending should help characterize accurate test performance, screening intervals, cost-effectiveness, direct comparison to FOBT and analysis of patient adherence. As tumour development pathways and potential target genes are further elucidated, refinements in multi-assay stool-based DNA testing portend enhanced test characteristics to detect and treat this genetically heterogeneous disease.

Prognostic significance of the labeling of Adnab-9 in pancreatic intraductal papillary mucinous neoplasms

BACKGROUND

Pancreatic intraductal papillary mucinous neoplasms (IPMN), morphologically resembling colonic adenomas, often have an indefinable malignant potential. We used a monoclonal antibody (MAb) raised against colonic adenomas, Adnab-9, to identify patients with a better prognosis.

METHODS

We assessed Adnab-9-labeled sections of these neoplasms from 50 patients, 13 pancreatic adenocarcinomas, and 32 colonic adenomas using standard immunohistochemical techniques.

RESULTS

26% of the IPMNs labeled with Adnab-9 as compared to 0% of pancreatic ductal cancers or surrounding benign tissues, (p < 0.001) and 53% of adenomas (p < 0.025). Labeling in IPMNs was usually seen in the noninvasive epithelium suggesting that Adnab-9 is a premalignant marker in these lesions. Labeling of invasive IPMN's identified a group of patients with a superior overall survival (p = 0.027).

CONCLUSION

Adnab-9 labeling-characteristics appear similar for both IPMNs and adenomatous polyps, suggesting that they are analogous lesions. Adnab-9 labeling may also be a useful prognostic marker for invasive intraductal papillary mucinous neoplasms.

Production and physical characteristics of composted poultry carcases

1. Experiments were designed to determine whether composting could be a safe and effective method for the disposal of poultry carcases in the UK climate. Laying hen carcases (125) were composted in a wooden compost bin over autumn and winter months, using the United States Department of Agriculture method. 2. The process took 8 weeks and effectively decomposed the carcases to leave only leg and breast bones. The compost was turned once, which ensured that all the material reached the high temperatures (60 degrees to 70 degrees C) required to control pathogens. Salmonella was fully heat-inactivated, indicating that many poultry-associated bacterial pathogens would also have been inactivated. 3. It is concluded that this method is suitable for use in the UK and provides a sanitised fertiliser supplement.

Tonsillectomy and adenoidectomy pathway plan of care for the pediatric patient in day surgery

The care of children undergoing tonsillectomy and adenoidectomy (T&A) in the day surgery setting can be costly, due in a large part to the length of stay after surgery. A clinical pathway standardizes the length of stay and, therefore, directly controls costs associated with outpatient T&A. A T&A pathway plan of care was developed at one institution to (1) decrease the cost of the procedure, (2) improve parent/patient satisfaction, and (3) maintain or improve the quality of care.

Reexamining the Relationship between Verbal Knowledge Background and Keyword Training for Vocabulary Acquisition

The literature on keyword training presents a confusing picture of the usefulness of the keyword method for foreign language vocabulary learning by students with strong verbal knowledge backgrounds. This paper reviews research which notes the existence of conflicting sets of findings concerning the verbal background-keyword training relationship and presents the results of analyses which argue against the assertion made by McDaniel and Pressley (1984) that keyword training will have minimal effect on students with high verbal ability. Findings from regression analyses of data from two studies did not show that the relationship between keyword training and immediate recall performance was moderated by verbal knowledge background. The disparate sets of findings related to the keyword training-verbal knowledge relationship and themes emerging from other research suggest that this relationship requires further examination.

Colonic retinoblastoma protein and proliferation in cancer and non-cancer patients

Both suppressor oncogene and proliferative activity are believed to indicate colon cancer risk. The retinoblastoma (Rb) gene is a suppressor oncogene affecting cell differentiation. Retinoblastoma gene inactivation is associated with tumour development. However, the relation of the Rb protein to cell proliferation and colon tumour formation is unknown. Retinoblastoma protein quantity was correlated with proliferative activity in flat, unaffected mucosa specimens from 36 cancer patients, 21 non-cancer control subjects and in 29 tumour tissue samples from cancer patients. Nuclear Rb protein was measured by using automated CAS-200 image analysis of monoclonal antibody labelled frozen sections from fresh, surgically removed tissue. All colon cells within 15 whole crypts were imaged. Proliferative activity was also measured by using analysis with Ki-67 monoclonal antibody. Retinoblastoma protein content correlated directly with proliferative activity in flat mucosa of non-cancer control subjects (r = 0.63; P < 0.001; n = 21). A significant correlation was also found in flat mucosa specimens of non-metastatic (Duke's stages A and B) cancer patients (r = 0.52; P < 0.01; n = 22). However, Rb protein did not correlate with proliferation in flat mucosa from metastatic (Duke's stages C and D) cancer patients (r = 0.03; NS; n = 14) or in cancer tissue (r = 0.068; NS; n = 29). Mucosal Rb protein in the colon normally increases as proliferation increases. Dissociation between Rb protein and colon proliferation may occur in flat mucosa in patients with a higher risk of metastatic tumour growth. Future studies comparing Rb protein quantity and proliferative activity may help identify high-risk colon cancer patients.

Colorectal cancer and noncancer patients have similar labeling indices by microscopy and computed image analysis

The labeling index (LI), a microscopic measurement of proliferative activity in colonic crypts, is proposed as an indicator of colonic cancer risk. Computed image analysis of proliferative regions is less labor intensive and more objective than is direct microscopy but has not been validated for labeling indices by direct comparison. The authors compared colonic crypt proliferation in 26 cancer and 13 noncancer patients by using Ki-67 monoclonal antibody (McAb) labeling of flat mucosa obtained from surgically removed, frozen specimens. In cancer patients, the mucosa specimen was excised 10 cm away from the tumor, and the LI was determined microscopically for the whole crypt, the upper two thirds, and the upper one third of 15 crypts. Nuclear antigen levels of 15 whole crypts were determined by using the CAS-200 computed image analyzer (Cell Analysis Systems, Elmhurst, IL). Cancer and noncancer specimens were compared as were microscopically determined LI and stained nuclei specimens by using image analysis. No statistically significant difference in proliferative activity of whole crypts, or the upper two thirds of crypts, was observed between cancer specimens and noncancer specimens from using either technique. However, a significant correlation existed between microscopic analysis and computed image analysis of labeled nuclei. Computed image analysis using Ki-67 McAb labeling can be used instead of microscopy to determine crypt LI, but neither method can be used to distinguish cancer specimens from noncancer specimens.

Superiority of the keyword method for backward recall in vocabulary acquisition

Differences in patterns of recall by one subject for forward and backward recall tasks are noted in use of the keyword method for vocabulary acquisition.

Colorectal cancer. Identifying and screening high-risk patients

Colorectal carcinoma is a major cause of cancer-related morbidity and mortality in the United States. High-risk patients should be appropriately identified and screened. Current recommendations from the American Cancer Society for the average-risk patient include both digital rectal examination and fecal occult blood testing annually beginning at age 40, as well as flexible sigmoidoscopy every 3 to 5 years beginning at age 50 after two normal annual examinations. If any of these tests yield positive results, complete examination of the colon with colonoscopy is indicated. The reliability, sensitivity, and cost-effectiveness of both digital examinations and stool occult blood testing have not been reported to be adequate for screening large populations. A more practical approach may be to omit stool testing and recommend screening with flexible sigmoidoscopy for average-risk patients aged 50 and older. Patients with distal adenomas should undergo colonoscopy and polypectomy as necessary, with follow-up colonoscopy determined by the number of polyps and success in removal.

Nitrite from inflammatory cells--a cancer risk factor in ulcerative colitis?

Elevated levels of luminal nitrite and a lowered luminal pH were found in 77 percent of patients with acute ulcerative colitis. No luminal nitrite was found in healthy control subjects. Nitrites are a secretory product of activated macrophages and neutrophils of the lamina propria, whereas the lowered luminal pH is due to diminished bicarbonate formation by impaired colonocytes. A hypothesis is put forward that nitrites, lowered pH, and bacterial amines are conducive to formation of carcinogenic n-nitroso compounds, which reflect a cancer risk in patients with ulcerative colitis dependent on the type and extent of inflammatory cell activation as well as metabolic impairment of colonic epithelial cells.

Effects of training in use of executive strategies on a verbal memory problem resulting from closed head injury

This case study reports attempts to improve the recall performance of an adolescent (GC) who had suffered a closed-head injury. GC had a very limited range of ways of processing both spoken and written information and showed significant recall problems. Initial training in the use of strategies for list learning resulted in improvement in paired-associate recall but showed that initiation and use of the newly learned strategies would not occur without prompting. Executive strategy training was provided to improve GC's ability to identify a memory problem and to initiate a general plan for dealing with that problem. This training involved consideration of task analysis, strategy selection and initiation, and monitoring of strategy use. Evidence of long-term maintenance of improvement in level of recall on both paired-associate and free recall tests was noted following the executive strategy training.

An assessment of proliferative and enzyme activity in transitional mucosa adjacent to colonic cancer

The mucosa within 2 cm of cancers of the large bowel (transitional mucosa) shows histologic and histochemical changes which may indicate premalignant change. In this study, the authors used specimens from resected colonic tissue to compare morphometric, proliferative, and enzyme markers in transitional mucosa with those in cancer tissue and with those in uninvolved mucosa at least 10 cm from the cancer. Proliferative activity was assessed using the Ki 67 monoclonal antibody technique whereas a variety of methods were used to determine enzyme activities in mucosal homogenates. When compared to uninvolved mucosa, crypts in transitional mucosa contained greater number of cells, were significantly deeper and wider and were more likely to be branched. However, crypts in transitional mucosa had a significantly lower labelling index using the Ki 67 technique and there was no evidence of a shift in the proliferative zone towards the bowel lumen. The activities of ornithine decarboxylase, thymidine kinase, alkaline phosphatase, and lactate dehydrogenase were similar in transitional and uninvolved mucosa. Cancer tissue showed significantly higher levels of activity for ornithine decarboxylase and lactate dehydrogenase. Transitional mucosa showed morphometric changes but there were no proliferative or enzyme markers to suggest a higher than expected risk for malignant change.

Zinc deficiency is associated with suppression of colonocyte proliferation in the distal large bowel of rats

As zinc status may influence susceptibility to colon cancer, we examined the effect of dietary zinc deficiency on the proliferation of epithelial cells (colonocytes) in the large bowel of rats. When compared to feed-restricted rats, those with zinc deficiency showed a significant reduction in proliferation in the distal colon as assessed by accumulated metaphase arrest and crypt cell production rates in vivo. Zinc deficiency had no apparent effect on thymidine kinase activity in colonocytes but was accompanied by minor changes in fecal mass and fecal pH. In rats, zinc deficiency is associated with a reduction in the rate of proliferation of colonocytes in the distal colon.

Proliferative activity in the proximal and distal colon of the rat after fasting and refeeding

Several methods were used to assess proliferation of colonocytes in the proximal and distal colon of the rat after fasting and refeeding. Those applied in vivo included metaphase arrest, labelling with bromodeoxyuridine and uptake of tritiated thymidine. The latter two techniques were also applied after isolation of colonocytes in vitro. Methods applied in vivo showed similar proliferation in the proximal and distal colon after fasting and enhanced proliferation in both regions after refeeding. However, the degree of enhancement was greater in the distal colon than in the proximal colon. In vitro, proliferation was enhanced in both the proximal and distal colon after refeeding but the degree of variability was greater than after assessment in vivo. Methods applied in vivo are preferred for assessment of proliferative activity in the rat colon, and major changes in proliferation in both proximal and distal colon can be induced by fasting-refeeding.

Antral gastrin concentrations in duodenal ulcer patients after cimetidine and highly selective vagotomy

Post-prandial serum levels of gastrin, the main hormonal stimulator of acid secretion, have been shown to be significantly elevated after HSV compared with controls. The mechanism for this elevation is not known but could be secondary to an increased antral gastrin concentration (AGC). In this study AGCs were measured in endoscopic biopsies before and at intervals of 6 and 32 weeks after HSV in 12 patients with duodenal ulcer. Results were compared with 13 normal controls and 12 duodenal ulcer patients treated with cimetidine for 6 weeks. Blood was taken for fasting serum gastrin concentration at each endoscopy. In the HSV group AGC significantly increased on both postoperative occasions when compared with pre-operative values (P less than 0.01). AGC also showed a significant correlation with time after HSV (r = 0.71; P less than 0.01). Only one patient, who had a persistent duodenal ulcer, failed to show an increase in AGC. Cimetidine failed to increase AGCs in duodenal ulcer patients after 6 weeks of treatment. However, a subgroup (n = 7) of cimetidine-treated patients with low pretreatment AGCs, below 10 ng/mg, did show a significant rise at 6 weeks (P less than 0.05). Fasting serum gastrin levels did not change significantly in any of the three groups. It is concluded that HSV causes a significant increase in AGC with time.

Neurologic syndrome associated with low levels of vitamin E in primary biliary cirrhosis

A 41-yr-old woman with primary biliary cirrhosis developed weakness and wasting in proximal muscles, areflexia, and decreased proprioceptive and vibratory sensation. Investigations revealed law serum levels of vitamin E and electromyographic and muscle biopsy changes consistent with a neuropathy. Sural nerve histology demonstrated axonal dystrophy with patchy demyelination. These features closely resemble a neurologic syndrome associated with chronic cholestatic liver disease and vitamin E deficiency in children. Adults with chronic cholestasis may also be susceptible to neurologic damage from prolonged malabsorption of vitamin E.

Detectable colonic nitrite levels in inflammatory bowel disease--mucosal or bacterial malfunction?

In the healthy colon, sodium nitrite stimulates mucosal metabolism of short-chain fatty acids and absorption of ions, both functions that are impaired in the mucosa of patients with ulcerative colitis (UC). To assess the role of nitrite in colonic inflammatory disease, sodium nitrite was measured in rectal dialysate of 49 subjects (18 controls, 23 UC and 8 other colitis). None of the control or quiescent UC patients had measurable levels of nitrite while 78% of patients with acute UC and 38% of patients with other colitis had measurable nitrite levels (acute UC vs. other colitis chi 2 = 5.555, p less than 0.02). Functional activity of the colonic mucosa, judged by bicarbonate output, was impaired in all subjects with measurable nitrite levels in UC. Detection of nitrite in acute colitis suggests impaired oxidation of nitrite to nitrate in the colonic mucosa or impaired luminal reduction of nitrite to NH4 by bacteria.

Observing executive activity in a simple assembly task

Performance of a group of adult trainees in a workshop for mentally retarded persons and that of an equivalent-MA group of third-grade children was observed in a toy construction task. Performances were video taped and subsequently coded for executive activity and other classes of behavior. A range of executive activities was identified, and these proved to be a powerful influence in discriminating between the groups. Other analyses of event sequences examined where executive activity occurred and which types of events typically followed such activity.

Colonic bicarbonate output as a test of disease activity in ulcerative colitis

No available test objectively measures impairment of function of the inflamed colonic mucosa in ulcerative colitis. To study function we assessed rectal bicarbonate output by rectal dialysis in the presence of water and bacterial fatty acid (n-butyrate) in 21 controls, 18 patients with acute ulcerative colitis, 12 patients with ulcerative colitis in remission, and 12 patients with other forms of colitis. In acute ulcerative colitis, compared with controls, bicarbonate output and pH was reduced (p less than 0.001); stimulated bicarbonate output with bacterial fatty acid (incremental bicarbonate output) was reduced by 80% in acute ulcerative colitis (p less than 0.01). Results indicate that bicarbonate output is a useful and selective test of mucosal function in acute ulcerative colitis. A diminished incremental bicarbonate output with n-butyrate supports the view of inadequate oxidation of bacterial fatty acids in vivo by the mucosa in ulcerative colitis. Whether the test will prove to be an index of prognosis or will aid choice between medical or surgical therapy requires further study.

Clinical evaluation of the 14C-Triolein Breath Test: a critical analysis

Twenty-two hospital patients without gastrointestinal symptoms and fourteen patients with clinically suspected fat malabsorption were studied using the 14C-Triolein Breath Test and three day fecal fat estimation. The 14C-Triolein Breath Test was 100% sensitive and 86% specific for fat malabsorption. Three day fecal fat estimations were 86% sensitive and 91% specific. These data confirm the high sensitivity and specificity obtained using the 14C-Triolein Breath Test. The speed and convenience of the 14C-Triolein Breath Test plus acceptable sensitivity and specificity make this a practical screening test to detect fat malabsorption.

Gallbladder and small intestinal regulation of biliary lipid secretion during intraduodenal infusion of standard stimuli

The gallbladder and small intestine are reservoirs for the bile acid pool during its enterohepatic circulation and, as such, may regulate biliary secretion of bile acid. During studies of biliary bile acid secretion, a stimulus to gallbladder contraction is continuously infused into the duodenum. Under these conditions, it is assumed that the gallbladder is tonically contracted and that the rate of bile acid secretion into the duodenum equals the hepatic bile acid secretion rate. However, secretion rates vary by as much as 100%, depending upon which of two standard stimuli is used. Therefore, we studied the role of gallbladder emptying and small intestinal transit in determining biliary lipid secretion rate and composition during infusion of these stimuli in five healthy subjects. Each subject was studied with a liquid formula containing 40% of calories as fat, and with an amino acid solution for 10 h. Bile acid, phospholipid, cholesterol, and markers were measured in duodenal bile and hourly secretion rates were calculated by marker dilution technique. Real-time gallbladder sonographs and serum pancreatic polypeptide levels were obtained every 30 min. Small bowel transit time was estimated levels were obtained every 30 min. Small bowel transit time was estimated by the breath hydrogen response after giving lactulose intraduodenally.During liquid formula infusion, gallbladder emptying was more complete, small intestinal transit was faster, and pancreatic polypeptide levels were higher. Secretion rates of all lipids were greater and molar percent cholesterol was lower. For the combined data from both infusions, the secretory relationships of cholesterol to bile acid, cholesterol to phospholipid, and phospholipid to bile acid were curvilinear. We conclude that more complete gallbladder emptying and faster intestinal transit increase the enterohepatic cycling of bile acids and lower the molar percent cholesterol of bile. Some of the fluctuation observed in biliary lipid secretion rates, especially during amino acid infusion, is due to gallbladder refilling and emptying.

A comparison of diazepam and phenoperidine in premedication for upper gastrointestinal endoscopy: a randomized double blind controlled study

A variety of agents are used as premedication for upper gastrointestinal endoscopy (U.G.E.). To our knowledge, no double blind studies have been performed to compare their value. In this study phenoperidine (2 mg i.v.) was compared with diazepam (t mg i.v.) in 200 consecutive patients undergoing elective U.G.E. The study was randomized and double blind in regard to both endoscopists and patients. All patients were given atropine (0.4 mg i.v.) and a throat spray with 2% amethocaine. Patients who needed supplemental medication were given diazepam and excluded from final analysis. A graded questionnaire was recorded by endoscopists and patients after U.G.E., and a further anonymous questionnaire was returned by patients four days later. Statistical analysis revealed that phenoperidine was superior at facilitating intubation and providing more relaxation as judged by the endoscopist. Patient questionnaires, four days after U.G.E., indicated less distress during intubation and examination with phenoperidine. Nausea, vomiting, amnesia and phlebitis were uncommon after either phenoperidine or diazepam.

Fractionated dose cholecystography: a comparison between iopanoic acid and sodium ipodate

Two randomised groups of 100 subjects each, undergoing oral cholecystography, were given either a 6 g fractionated dose of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) to determine the relative merits of this dose schedule. Exclusions to the study were pregnancy and iodine sensitivity. Calculi or abnormal gallbladder opacification were present in 45% of subjects. Both agents were equally effective in demonstrating abnormalities, although bile duct visualisation was better using iopanoic acid (P less than 0.05). Of 46 subjects with abnormal cholecystograms subsequently undergoing surgery, all had the diagnosis confirmed. Side effects occurred in 63% of all subjects, being twice as common in those taking iopanoic acid (P less than 0.01). Sodium ipodate in a large fractionated dose is favoured because of the lower occurrence of side effects without loss of diagnostic accuracy.

Thyroid, renal, and hepatic function tests following cholecystography with high-dose contrast agents

Serum biochemical tests were observed for about three weeks following oral cholecystography with fractionated high doses (6 g) of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) in 24 and 29 patients, respectively. Both agents produced similar effects. No significant changes were seen in renal or hepatic function except for a mild increase in bilirubin on day 22. Serum urate decreased 10% on day 4, but the change was not significant. On days 4 and 11, there were significant increases in thyroid-stimulating hormone, thyroxine and free thyroxine index, and a moderate fall in triiodothyronine. Reverse triiodothyronine increased sharply on day 4. The pattern of changes observed suggests that these contrasts interfere with the extrathyroidal deiodination of iodothyronines. The temporary rise in thyroxine and free thyroxine index exceeded reference ranges in about half of all subjects, but they remained clinically euthyroid. Thyroid function tests should be interpreted with caution within three weeks of cholecystography.

Type II hyperlipoproteinemia in mother and twins

A 36-year-old housewife with type II hyperlipoproteinemia became pregnant with twins. Although the pregnancy was uneventful, the serum triglycerides were elevated during the third trimester, the delivery, and early puerperium. The mother had no complications directly related to the pregnancy despite hypercholesterolemia, coronary atherosclerosis, and hypertension. Cord blood cholesterol and beta lipoprotein in both twins were greater than twice normal. Despite this genetic defect in lipid transport the twins have developed normally during their first year of life. Since lipids and lipoproteins do not cross the placental barrier, it is concluded that type II hyperlipoproteinemia may have been present at birth.