Phase segregation and nanoconfined fluid O2 in a lithium-rich oxide cathode

Lithium-rich oxide cathodes lose energy density during cycling due to atomic disordering and nanoscale structural rearrangements, which are both challenging to characterize. Here we resolve the kinetics and thermodynamics of these processes in an exemplar layered Li-rich (Li1.2-xMn0.8O2) cathode using a combined approach of ab initio molecular dynamics and cluster expansion-based Monte Carlo simulations. We identify a kinetically accessible and thermodynamically favourable mechanism to form O2 molecules in the bulk, involving Mn migration and driven by interlayer oxygen dimerization. At the top of charge, the bulk structure locally phase segregates into MnO2-rich regions and Mn-deficient nanovoids, which contain O2 molecules as a nanoconfined fluid. These nanovoids are connected in a percolating network, potentially allowing long-range oxygen transport and linking bulk O2 formation to surface O2 loss. These insights highlight the importance of developing strategies to kinetically stabilize the bulk structure of Li-rich O-redox cathodes to maintain their high energy densities.

Anion-polarisation-directed short-range-order in antiperovskite Li2FeSO

Short-range ordering in cation-disordered cathodes can have a significant effect on their electrochemical properties. Here, we characterise the cation short-range order in the antiperovskite cathode material Li₂FeSO, using density functional theory, Monte Carlo simulations, and synchrotron X-ray pair-distribution-function data. We predict partial short-range cation-ordering, characterised by favourable OLi₄Fe₂ oxygen coordination with a preference for polar cis-OLi₄Fe₂ over non-polar trans-OLi₄Fe₂ configurations. This preference for polar cation configurations produces long-range disorder, in agreement with experimental data. The predicted short-range-order preference contrasts with that for a simple point-charge model, which instead predicts preferential trans-OLi₄Fe₂ oxygen coordination and corresponding long-range crystallographic order. The absence of long-range order in Li₂FeSO can therefore be attributed to the relative stability of cis-OLi₄Fe₂ and other non-OLi₄Fe₂ oxygen-coordination motifs. We show that this effect is associated with the polarisation of oxide and sulfide anions in polar coordination environments, which stabilises these polar short-range cation orderings. We propose that similar anion-polarisation-directed short-range-ordering may be present in other heterocationic materials that contain cations with different formal charges. Our analysis illustrates the limitations of using simple point-charge models to predict the structure of cation-disordered materials, where other factors, such as anion polarisation, may play a critical role in directing both short- and long-range structural correlations.

Probing Mg Intercalation in the Tetragonal Tungsten Bronze Framework V4Nb18O55

While commercial Li-ion batteries offer the highest energy densities of current rechargeable battery technologies, their energy storage limit has almost been achieved. Therefore, there is considerable interest in Mg batteries, which could offer increased energy densities in comparison to Li-ion batteries if a high-voltage electrode material, such as a transition-metal oxide, can be developed. However, there are currently very few oxide materials which have demonstrated reversible and efficient Mg²⁺ insertion and extraction at high voltages; this is thought to be due to poor Mg²⁺ diffusion kinetics within the oxide structural framework. Herein, the authors provide conclusive evidence of electrochemical insertion of Mg²⁺ into the tetragonal tungsten bronze V₄Nb₁₈O₅₅, with a maximum reversible electrochemical capacity of 75 mA h g^-1, which corresponds to a magnesiated composition of Mg₄V₄Nb₁₈O₅₅. Experimental electrochemical magnesiation/demagnesiation revealed a large voltage hysteresis with charge/discharge (1.12 V vs Mg/Mg²⁺); when magnesiation is limited to a composition of Mg₂V₄Nb₁₈O₅₅, this hysteresis can be reduced to only 0.5 V. Hybrid-exchange density functional theory (DFT) calculations suggest that a limited number of Mg sites are accessible via low-energy diffusion pathways, but that larger kinetic barriers need to be overcome to access the entire structure. The reversible Mg²⁺ intercalation involved concurrent V and Nb redox activity and changes in crystal structure, as confirmed by an array of complementary methods, including powder X-ray diffraction, X-ray absorption spectroscopy, and energy-dispersive X-ray spectroscopy. Consequently, it can be concluded that the tetragonal tungsten bronzes show promise as intercalation electrode materials for Mg batteries.

Diamond-Graphene Composite Nanostructures

The search for new nanostructural topologies composed of elemental carbon is driven by technological opportunities as well as the need to understand the structure and evolution of carbon materials formed by planetary shock impact events and in laboratory syntheses. We describe two new families of diamond-graphene (diaphite) phases constructed from layered and bonded sp³ and sp² nanostructural units and provide a framework for classifying the members of this new class of materials. The nanocomposite structures are identified within both natural impact diamonds and laboratory-shocked samples and possess diffraction features that have previously been assigned to lonsdaleite and postgraphite phases. The diaphite nanocomposites represent a new class of high-performance carbon materials that are predicted to combine the superhard qualities of diamond with high fracture toughness and ductility enabled by the graphitic units and the atomically defined interfaces between the sp³- and sp²-bonded nanodomains.

Quantifying hexagonal stacking in diamond

Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.

Phase stability of intercalated V2O5 battery cathodes elucidated through the Goldschmidt tolerance factor

Orthorhombic V₂O₅ is a promising Mg battery cathode material, and reversible intercalation in the layered α-phase has been claimed experimentally. However, these results, based on electrochemistry and XRD, are controversial. Previous computational studies have predicted high activation barriers (∼1 eV) for ionic migration in α-V₂O₅, although improved Mg²⁺ mobility is expected in the δ-phase. Here, hybrid-exchange density functional theory is used to discuss structure, stability and intercalation in the α and δ phases, beginning with a model system with MV₂O₅ stoichiometry, and varying ionic radius of the M cations. The relative stability of the two phases upon intercalation of M is rationalised through a tolerance factor-like behavioural trend, providing a framework for phase selection using intercalants of different ionic size. This tolerance factor behaviour is due to the presence of ferroelectrically distorted (2 × 2 × 2) perovskite blocks within the α-V₂O₅ structure. The δ-phase is found to undergo a barrierless phase change to α in fully charged (de-intercalated) Mg_xV₂O₅ (x = 0), indicating that stabilisation of δ-Mg_xV₂O₅ is required at low x if the δ phase is to be retained for higher Mg mobility. By employing dispersion interactions to accurately reproduce the interlayer distance, activation barriers for ion migration are found to be higher than reported in previous studies, clarifying questions regarding the extent of Mg intercalation that can be achieved experimentally. Interlayer ions are found to lower activation barriers for Mg²⁺ mobility by up to ∼330 meV in the α phase by expanding the interlayer space. The results address open questions about the electrochemical performance of orthorhombic V₂O₅ as Mg battery cathode material, and indicate atomic level mechanisms that activate ionic mobility in layered V₂O₅.

Thermodynamics and defect chemistry of substitutional and interstitial cation doping in layered α-V2O5

A systematic study of the location and energetics of cation dopants in α-V₂O₅ has been conducted using pair-potential methods, supplemented by first-principles calculations.

Theoretical insights into the nature of synergistic enhancement in bimetallic CoTiAlPO-5 catalysts for ammonia activation

Bimetallic catalytic synergy, the concurrent action of two different metal ions in the same material, has resulted in improved efficiency in many catalytic systems and for a range of chemical processes.

Clinical correlation of extensive-stage small-cell lung cancer genomics

BACKGROUND

Genomic studies in small-cell lung cancer (SCLC) lag far behind those carried out in nonsmall-cell lung cancer (NSCLC). To date, most SCLC studies have evaluated patients with surgically resectable disease. Here we sought to evaluate the genomic mutation spectrum of 'every-day' SCLC patient tumors with extensive stage disease (ES-SCLC) and to correlate mutations with the main clinical outcomes of response to chemotherapy, progression-free (PFS) and overall (OS) survival.

PATIENTS AND METHODS

A total of 50 SCLC patient tumors were examined in this study; targeted exome sequencing was obtained on 42 patients and whole-exome sequencing on 8 patients. Mutated genes were correlated with clinical outcomes using Kaplan-Meier methods (PFS, OS) and logistic regression (chemo-response). RB1 protein expression was detected by either western blotting of cultured cell lysates or immunohistochemistry of tumor specimens.

RESULTS

In all, 39 patients had ES-SCLC; 15 patients had either primary refractory/resistant disease and 21 patients had sensitive disease. The two most frequently mutated genes were TP53 (86%) and RB1 (58%); other frequently mutated genes (>10% patients) were involved in epigenetic regulation as well as the mTOR pathway. We identified a number of low-frequency, targetable mutations, including RICTOR, FGFR1, KIT, PTCH1 and RET. Using multivariate analysis, RB1 was the only significant factor (P = 0.038) in predicting response to first-line chemotherapy, with an odds ratio of 5.58 comparing mutant RB1 with wild-type. Patients with mutant RB1 had both better OS (11.7 versus 9.1 months P = 0.04) and PFS (11.2 versus 8.6 months, P = 0.06) compared with patients with wild-type RB1. Interestingly, ∼25% of SCLC cell lines and tumor specimens expressed RB1 protein, possibly representing the subgroup with wild-type RB1.

CONCLUSIONS

We found that SCLC tumors harboring no mutation in RB1 had a poor response to chemotherapy.

Characteristics of prion-filtered red cells suspended in pathogen-inactivated plasma (MB treated or solvent-detergent treated) for neonatal exchange transfusion

BACKGROUND AND OBJECTIVES

Neonates undergoing exchange transfusion require <5-day-old red cells suspended in plasma. This study assesses the effect of replacing the saline, adenine, glucose and mannitol (SAGM) of prion reduced (P-Capt) red cells with either methylene blue-treated plasma (MBTFFP) or OctaplasLG to reduce the risk of variant Creutzfelt-Jakob disease transmission.

MATERIALS AND METHODS

Twenty leucoreduced red cell units in SAGM were prion reduced on day 1. The SAGM was replaced by MBTFFP (n=10) or OctaplasLG (n=10). The units were irradiated and stored at 4°C for 24 h. A further 20 units were stored for 5 days before being processed as above. Haemolysis (%), potassium, ATP, 2,3-DPG and plasma proteins were measured.

RESULTS

Haemolysis remained low (≤0·16%). Following irradiation and storage, red cells in both types of plasma showed similar changes in potassium and ATP concentrations. The 2,3-DPG concentrations were well maintained although lower in red cells in OctaplasLG compared with those in MBTFFP (4·79 vs. 6·83 μmoles/g Hb on day 6). MBTFFP contained lower concentrations of fibrinogen, FV and FVIII. In OctaplasLG, alpha-2-antiplasmin was approximately 0·4 U/ml lower than in MBTFFP. After 24 h at 4°C, free protein S in OctaplasLG fell from 0·82 to 0·57 IU/ml. Other plasma proteins, in both types of plasma, were stable.

CONCLUSIONS

Red cells in both types of plasma demonstrated similar storage characteristics. The plasma proteins, except protein S in OctaplasLG, were stable over 24 h at 4°C in both types of plasma, and low FVIII concentrations were noted in the MBTFFP (group O) units used.

New algorithm for the treatment of gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is associated with a variety of typical and atypical symptoms. Patients often present in the first instance to a pharmacist or primary care physician and are subsequently referred to secondary care if initial management fails. Guidelines usually do not provide a clear guidance for all healthcare professionals with whom the patient may consult.

AIM

To update a 2002-treatment algorithm for GERD, making it more applicable to pharmacists as well as doctors.

METHODS

A panel of international experts met to discuss the principles and practice of treating GERD.

RESULTS

The updated algorithm for the management of GERD can be followed by pharmacists, for over-the-counter medications, primary care physicians, or secondary care gastroenterologists. The algorithm emphasizes the importance of life style changes to help control the triggers for heartburn and adjuvant therapies for rapid and adequate symptom relief. Proton pump inhibitors will remain a prominent treatment for GERD; however, the use of antacids and alginate-antacids (either alone or in combination with acid suppressants) is likely to increase.

CONCLUSION

The newly developed algorithm takes into account latest clinical practice experience, offering healthcare professionals clear and effective treatment options for the management of GERD.

Extended storage of platelets in SSP platelet additive solution

BACKGROUND AND OBJECTIVES

The aim of this study was to investigate the effects of extended storage of pooled random platelets in SSP+ additive solution (MacoPharma).

MATERIALS AND METHODS

Eight buffy coat-derived, pooled, leucoreduced platelet concentrates were prepared in 75% SSP+, 25% plasma using Fresenius/NPBI Composelect thrombocyte polishing filter (TPF) systems. Platelet concentrates were stored for 19 days in polyolefin storage bags and samples for in vitro analysis were taken at various time-points during storage.

RESULTS

Platelet yields were lower than seen routinely when platelets are prepared in 100% plasma. The in vitro quality of the platelets stored in SSP+ was maintained until day 9. Glucose was depleted by day 12 and this was accompanied by a rapid fall in pCO2, a rise in pO2 and a cessation of lactate production. ATP and bicarbonate concentrations fell, the platelets began to swell and the ability to swirl decreased. Soluble P-selectin, glycocalicin, and regulated on activation, normal, T-cell expressed, and secreted (RANTES) concentrations increased, as did P-selectin expression. Loss of platelets and an increase in lacate hydrogenase concentration indicated that lysis had occurred. However, the pH remained between 6.4 and 7.4.

CONCLUSIONS

The results suggest that SSP+ could be used for platelet storage for up to 9 days. However, the preparation of platelets in the additive requires some optimization. In vivo studies are required to confirm these in vitro results.

Separation of whole blood into plasma and red cells by using a hollow-fibre filtration system

BACKGROUND AND OBJECTIVES

The aim of this study was to assess the separation of whole blood into red cells and plasma by using the Sangofer device, which is a gravity-fed, hollow-fibre system. The components would then be compared with those produced by the use of more elaborate technical equipment.

MATERIALS AND METHODS

Ten whole-blood units were leucoreduced by using a WBF2 filter and immediately separated into red cells and plasma by using the Sangofer blood-separation device. Red cells were stored in additive solution and tested on days 1 and 42. The plasma was assayed for levels of various coagulation factors and for markers of both coagulation and complement activation.

RESULTS

The red-cell parameters were similar to those obtained when routine centrifugation methods were used. The filter did not cause haemolysis. Levels of plasma factor VIII and factor XI were lower than those seen in routinely produced leucoreduced plasma units but there was no evidence of activation of the coagulation and complement systems.

CONCLUSIONS

The Sangofer device is simple and straightforward to use and eliminates the need for both centrifugation and automated separation steps during the processing of whole blood into red cells and plasma components. Minor changes are required to make the procedure easier to incorporate into routine use.

Response of the North Island brown kiwi, Apteryx australis mantelli and the lesser short-tailed bat, Mystacina tuberculata to a measured dose of rabbit haemorrhagic disease virus

Four North Island brown kiwis and six lesser short-tailed bats were inoculated intramuscularly with 300 000 rabbit lethal doses of rabbit haemorrhagic disease (RHD) virus. No clinical abnormalities were observed in the kiwis and bats throughout the study period. Although no viraemia was detected in any of the kiwis, all four birds produced a serological response to RHD virus above the positive cut-off by 14 days after inoculation, and in two of the birds, antibodies persisted for over 5 months. Two kiwis were killed 48 days after inoculation. Their tissues were examined for lesions, and for the presence of persistent virus by both reverse transcription polymerase chain reaction and by inoculation of tissue suspensions into rabbits. No gross or histological lesions suggestive of a viral infection were detected and tests for detection of virus were negative. The serological response in the kiwis was probably due to the birds responding to viral antigen in the inoculum rather than to multiplication of the virus. None of the bats showed a serological response to RHD virus above the positive cut-off by 14 days after inoculation and the results of the pathological and virological examinations were negative.

Review article: Helicobacter pylori and gastro-oesophageal reflux disease

Epidemiological studies demonstrate a negative association between Helicobacter pylori infection and gastro-oesophageal reflux disease and its complications. This might represent a protective effect because of the tendency for H. pylori infection to lower gastric acid secretion with advancing age. However, studies of the effect of H. pylori eradication on gastro-oesophageal reflux disease have failed to show any worsening of gastro-oesophageal reflux disease symptoms. Several interactions between H. pylori and proton-pump inhibitor therapy used to treat gastro-oesophageal reflux disease need to be considered. Helicobacter pylori infection improves the control of gastric acidity by proton-pump inhibitors and this produces a small advantage in clinical control of reflux disease. The infection prevents rebound acid hypersecretion occurring when proton-pump inhibitor therapy is discontinued. However, concerns have been expressed that the body gastritis induced by proton-pump inhibitor therapy in H. pylori-infected subjects might increase the risk of gastric cancer. At present, it is unclear whether H. pylori should be eradicated in gastro-oesophageal reflux disease patients.

Helicobacter pylori infection reduces systemic availability of dietary vitamin C

OBJECTIVE

Helicobacter pylori infection is recognized to lower the concentration of vitamin C in gastric juice. The objective of this study was to assess the effect of the infection on the systemic availability of dietary vitamin C.

METHODS

The study involved 1,106 men and women aged 25-74 randomly recruited from the population of north Glasgow. Their H. pylori status, dietary vitamin C intake calculated from a food frequency questionnaire and plasma vitamin C concentration were measured. Correction was made for potential confounding factors such as age, sex, smoking and social status.

RESULTS

The mean plasma vitamin C concentration in those who were H. pylori-positive was only 65% of that in those classified negative. Although partly explained by differences in age, sex, social class, smoking and vitamin C intake, the systemic reduction was observed across almost all sub-groups after stratification. Correction for all these factors still gave a plasma vitamin C level for H. pylori positives which was only 80% of that for negatives (P < 0.0001).

CONCLUSIONS

H. pylori substantially impairs the bio-availability of vitamin C. This, together with the reduced vitamin C intake of H. pylori-positive subjects, markedly reduces the plasma vitamin C level of infected subjects. The reduced circulating levels of vitamin C in H. pylori-infected subjects may contribute to the aetiology of gastric cancer, as well as other diseases associated with anti-oxidant deficiency.

Involvement of c-Fos in signaling grp78 induction following ER calcium release

Release of calcium from the endoplasmic reticulum (ER) signals an increase in transcription of both the early response gene, c-fos, and the late response gene, grp78. We have used thapsigargin (TG), an ER calcium-ATPase pump inhibitor that induces calcium release from the ER, to investigate the possible involvement of c-Fos, a component of the AP-1 transcription factor, in grp78 induction. Two cell lines with markedly different responses to TG treatment were employed: the WEHI7.2 mouse lymphoma line in which TG fails to induce grp78, and the MDA-MB-468 mammary epithelial line in which TG induces grp78. In WEHI7.2 cells, TG-induced calcium release triggers a rapid increase in c-fos mRNA, but the level of c-Fos protein decreases due to degradation by the multicatalytic proteasome. C-FosdeltaC, a proteasome resistant c-Fos mutant with AP-1 activity similar to that of wild type c-Fos, restores grp78 induction in WEHI7.2 cells, detected by both Northern hybridization and a grp78 promoter-luciferase reporter assay. In MDA-MB-468 cells, TG-mediated calcium release induces a sustained elevation of c-Fos protein that precedes grp78 induction. A region of the grp78 promoter containing both ERSE and CORE regions, but missing TRE and CRE regions, is sufficient to mediate induction of reporter luciferase activity. Induction of this reporter was blocked by A-Fos, a dominant negative inhibitor of c-Fos. Also, the induction of grp78-luciferase reporter activity was inhibited by c-fos antisense mRNA. In summary, the findings indicate that c-Fos is involved in signaling grp78 induction following TG treatment, and that grp78 induction is inhibited by proteasome-mediated c-Fos degradation.

Should non-invasive Helicobacter pylori testing replace endoscopy in investigation of dyspepsia?

Our knowledge of Helicobacter pylori infection is now changing the way in which we investigate patients presenting with dyspepsia, with noninvasive H. pylori testing replacing endoscopy. Non-invasive H. pylori testing has been shown to be useful in predicting the underlying diagnosis in patients presenting with dyspepsia. Several studies have shown that 20-50% of dyspeptic patients with a positive H. pylori test will have evidence of underlying ulcer disease or duodenitis. In contrast, less than 5% of dyspeptic patients with a negative H. pylori test will have evidence of ulcer disease and in these subjects, the likeliest diagnosis is gastroesophageal reflux disease. This has led to many groups recommending that noninvasive H. pylori testing should be used in place of endoscopy, with all those testing positive being given anti-H. pylori therapy and those testing negative being treated symptomatically. One concern about nonendoscopic management of dyspeptic patients is the possibility of missing underlying malignancy but studies have shown that in western countries this is rare in patients less than 55 years of age presenting with dyspepsia in the absence of sinister symptoms. There is increasing evidence supporting eradication of H. pylori infection in dyspeptic patients without ulcer disease. Meta-analysis of four prospective randomized trials indicates that such treatment is superior to placebo in about 10% of subjects. H. pylori-positive dyspeptic patients are also recognized to have an increased risk of developing ulcer disease in the future which will be removed by treating the infection. Another justification for eradicating the infection in the absence of ulcer disease is the fact that H. pylori infection is now proven to be a risk factor for gastric cancer. Prospective randomized studies comparing endoscopy with noninvasive H. pylori testing in the management of dyspeptic patients indicate that managing dyspepsia by noninvasive H. pylori testing is at least as effective as endoscopic-based management in producing symptomatic resolution and saves a substantial number of endoscopic procedures. There is therefore now substantial evidence indicating that noninvasive H. pylori testing should be used in place of endoscopy to determine the management of younger dyspeptic patients without sinister symptoms and who are not taking nonsteroidal anti-inflammatory drugs.

Quality assurance by a commercial flow cytometry method of leucodepletion of whole blood donations: initial application of universal testing and proposals for a batch-release sampling plan

We have used the Becton-Dickinson LeucoCOUNT test to monitor residual leucocytes in whole blood by flow cytometry following leucodepletion filtration. This test was found to be quick, robust and reliable, and allowed measurement of residual leucocytes down to 2.25 x 104 leucocytes per unit, which was found to match approximately the limit of filter proficiency. The results of testing > 1000 units showed a lognormal distribution with means between log(10) 4.864 (0.73 x 105) and log(10) 5.016 (1.04 x 105) leucocytes per unit in the three different homogeneous groups of filtered units studied. The numbers of units with residual leucocytes exceeding the 5 x 106 upper threshold were 1/577, 2/457 and 0/87 in these groups. The filtration processes were validated according to the published BEST working party guidelines and were well within the 99% confidence and 95% tolerance target for the 5 x 106 upper threshold set for the UK. A sampling plan based on British Standard BS 6001 with elimination of outliers by the extreme studentized deviate (Grubbs' test) was evaluated on random samples from these groups and has been adopted locally as a prospective batch-release criterion for release of leucodepleted blood.

An investigation into factors associated with Helicobacter pylori infection

This study aims to estimate the prevalence of Helicobacter pylori in Glasgow, and to provide a systematic analysis of factors associated with this prevalence. The data used are from a random population sample of 793 men and 838 women aged 25-64 years conducted in 1995. The prevalence is estimated to be 66% (95% confidence interval: 63-68%); a level that is more typical of developing countries. Prevalence increases with age and social deprivation (P<0.0001) and is slightly higher in men than women (P = 0.07). After adjustment for age, social class, and sex group, H. pylori prevalence increases with increased cotinine (tobacco consumption) (P = 0.0005), increased number of siblings (P<0.0001), and decreased height (P = 0.03). Prevalence of coronary heart disease, hypertension, diabetes and intermittent claudication, alcohol consumption, fibrinogen, total serum cholesterol, HDL cholesterol, triglycerides, marital status, systolic and diastolic blood pressure had no independent association. The infection seems to be spread more readily in deprived, relatively crowded living conditions in childhood. The independent relationship with smoking suggests a possible second source of spread of infection in later years. The high degree of social deprivation in Glasgow is suggested as a major explanation of the high H. pylori prevalence found there.

Symptomatic benefit from eradicating Helicobacter pylori infection in patients with nonulcer dyspepsia

BACKGROUND

The eradication of Helicobacter pylori infection is beneficial in patients with gastric or duodenal ulcers. The value of eradicating the infection in patients with dyspepsia and no evidence of ulcer disease is not known.

METHODS

We performed a randomized, placebo-controlled trial comparing the efficacy of treatment for two weeks with 20 mg of omeprazole orally twice daily, 500 mg of amoxicillin three times daily (with 500 mg of tetracycline three times daily substituted for amoxicillin in patients allergic to penicillin), and 400 mg of metronidazole three times daily (160 patients) with that of omeprazole alone (158 patients) for resolving symptoms of dyspepsia in patients with H. pylori infection but no evidence of ulcer disease on upper gastrointestinal endoscopy. Symptoms were assessed with the Glasgow Dyspepsia Severity Score, with resolution of symptoms defined as a score of 0 or 1 in the preceding six months (maximal score, 20). One year later the patients were assessed to determine the frequency of the resolution of symptoms.

RESULTS

One month after the completion of treatment, 132 of 150 patients (88 percent) in the group assigned to received omeprazole and antibiotics had a negative test for H. pylori, as compared with 7 of 152 (5 percent) in the group assigned to receive omeprazole alone. One year later, dyspepsia had resolved in 33 of 154 patients (21 percent) in the group given omeprazole and antibiotics, as compared with 11 of 154 (7 percent) in the group given omeprazole alone (95 percent confidence interval for the difference, 7 to 22 percent; P<0.001). Among the patients in the group given omeprazole and antibiotics, the symptoms resolved in 26 of the 98 patients (27 percent) who had had symptoms for five years or less, as compared with 7 of the 56 patients (12 percent) who had had symptoms for more than five years (P=0.03).

CONCLUSIONS

In patients with H. pylori infection and nonulcer, or functional, dyspepsia, treatment with omeprazole and antibiotics to eradicate the infection is more likely to resolve symptoms than treatment with omeprazole alone.

Further complexities of the Rh antigen D disclosed by testing category DII cells with monoclonal anti-D

The reaction pattern of monoclonal anti-D with category DII cells differed from those of other category D cells. DII cells express epD1, epD2, epD3, epD5, epD6/7 and epD8 but lack epD4 and a new epitope epD9. The new epitope, epD9, is proposed to explain the failure of some monoclonal anti-D (previously considered to be anti-epD3) to react with DII cells.

Comparative bioavailability of two flurbiprofen products: stereospecific versus conventional approach

In this randomized, crossover study comparing the bioavailability of a film-coated (Ansaid) with a sugar-coated (Froben) 100 mg tablets of racemic flurbiprofen in 23 healthy young men, no significant differences were found for Cmax, tmax or AUC, using a nonstereoisomeric assay for flurbiprofen. Minor differences in the appearance of flurbiprofen in serum during the first 30-min post-dosing period were noted, with Ansaid appearing earlier than Froben. These differences likely reflect dissolution rate dissimilarity between the two products. Stereospecific determinations demonstrate a small (7.8 per cent) but significant difference in AUC of the active S-configuration (Froben greater than Ansaid). No significant differences between Ansaid and Froben were found for tmax or Cmax for the S-flurbiprofen. In bioequivalency studies of chiral drugs, stereospecific approaches provide a more accurate assessment of products.

Performance profiles of topical antimicrobials in vitro

The in-vitro efficacy of commercially available topical antimicrobial products against control strains and those from clinical material are compared with an agar diffusion model. The MICs of the constituent antimicrobial compounds have been determined for the same organisms. Plotting the inhibition zone diameters produced by the topical products against the log10 MICs of their constituent antimicrobial compound(s) gives overall product performance profiles for a range of organisms. These profiles confirm that the formulation of a topical product clearly modifies the response obtained with a specific antimicrobial compound.

Stability of murine monoclonal anti-A, anti-B and anti-A,B ABO grouping reagents and a multi-centre evaluation of their performance in routine use

We have previously reported the production of 3 murine monoclonal reagents for ABO typing (designated ES-9, ES-4 and ES-15). This study presents results of tests of stability of these 3 reagents, together with a fourth murine monoclonal antibody (LM103/107). In addition, data are also presented from a multi-centre evaluation of the performance of the murine monoclonal reagents in routine ABO typing of both donors and patients using a wide variety of techniques, both manual and automated. The potency and stability of the 4 monoclonal antibody based reagents is compared with a broad selection of monoclonal and polyclonal ABO typing reagents. The reagents used for comparison were produced by European and United States manufacturers in both the public and private sector and are widely used in routine ABO typing. The Scottish monoclonal reagents have been used successfully to ABO type over 500,000 blood samples in 7 centres within the UK, with no discrepant results.

Polyethylene glycol in the production of blood grouping reagents: some further advantages

The use of various water-soluble non-ionic polymers, including polyethylene glycol (PEG) 8000, has been described in the preparation of diagnostic blood grouping reagents. The major advantages of using PEG in this way are ease of preparation and the ability to concentrate antibodies. We describe here two previously unreported advantages of using PEG: (i) substantial reductions in the volume of red cells required for adsorption of isoagglutinins; and (ii) the ability to store PEG precipitates in a 'dry' form substantially reduces storage requirements.

Examination of mucosal surfaces by scanning electron microscopy before and after removal of debris

A rapid method is described whereby gastrointestinal biopsy specimen surfaces can be examined by scanning electron microscopy with overlying tract contents (debris) intact, and also re-examined after cleaning to determine the structure of the underlying mucosal surface. The conductive coating of gold is removed using mercury, a non-wetting agent. The specimen surface is suitably cleaned of debris after a brief ultrasonication in absolute ethanol which mixes with the transitional fluid (CO2) used for critical point drying.

Fatal respiratory disease in Nilgiri tahr: possibly malignant catarrhal fever

Nilgiri tahr (Hemitragus hylocrius) are native to India and are a rare zoo exhibit. This report describes an acute respiratory disease in tahr that caused the death of 15 of 16 animals in an extensive exhibit of about 35 acres where they were housed together with a variety of other exotic species of ruminants. The deaths occurred in two separate outbreaks and were associated with losses from malignant catarrhal fever in other ruminants in the exhibit. The most prominent clinical sign was severe dyspnea, and death occurred within five days. The principal lesions were an acute nonsuppurative inflammation of the respiratory tract and pulmonary vessels, lymphadenopathy and lymphoid cell infiltration in the organs of some animals. It was conjectured that the tahr died of a unique pneumonic form of malignant catarrhal fever. Attempts at viral isolation were negative.

Mortality in little penguins (Eudyptula minor) along the coast of Victoria, Australia

Forty-eight little penguins (Eudyptula minor) consisting of 21 (43.7%) mature, 18 (37.5%) juvenile and nine (18.7%) of undetermined age, from 10 Victorian coastal localities were examined during 1977-78. Thirty-seven (77%) of all penguins were in poor body condition with moderate to heavy burdens of internal and external parasites. Acute parasitic gastric ulceration with accompanying hemorrhage, was implicated in the death of four birds. Chronic gastric ulcers were thought to have caused appetite depression and starvation in 28 birds. Other significant lesions encountered included renal coccidiosis, parasitic cholangiohepatitis and pulmonary aspergillosis. It is suggested that the increased mortality experienced during 1977-78 was due to starvation or to exacerbation of the effects of existing parasite burdens on starving and exhausted birds.