Incidence and Risk of Glucocorticoid-Associated Adverse Effects in Patients With Rheumatoid Arthritis

OBJECTIVE

Using the UK Clinical Practice Research Datalink, we examined the incidence of glucocorticoid (GC)-related serious adverse events (SAEs) in rheumatoid arthritis (RA) and non-RA patients and quantified the risk of SAEs in patients with RA.

METHODS

We matched incident patients with RA to an age- and sex-matched, non-RA comparison group of equal size. In a cohort analysis, we estimated incidence rates (IRs) and IR ratios (IRRs) for GC-related AEs (i.e., diabetes mellitus [DM], osteoporosis, fractures, glaucoma, hypertension, gastrointestinal [GI] perforation or bleeding, thrombotic stroke or myocardial infarction [MI], or death), stratified by GC use. We conducted a series of nested case-control analyses among patients with RA, evaluating the effects of increasing cumulative and average daily GC dose. Cases of each outcome were matched to controls for age, sex, and general practice. We calculated adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) for each outcome.

RESULTS

Patients with RA had a higher incidence for all investigated SAEs except glaucoma, compared to non-RA patients. IRRs were greater in those patients prescribed a GC than in those without. In patients with RA, GCs were associated with an elevated risk of DM (adjusted OR 1.33 [95% CI 1.14-1.56]), osteoporosis (adjusted OR 1.41 [95% CI 1.25-1.59]), thrombotic stroke or MI (adjusted OR 1.28 [95% CI 1.07-1.52]), serious infection (adjusted OR 1.28 [95% CI 1.11-1.48]), and death (adjusted OR 1.33 [95% CI 1.19-1.48]). There was a trend of increasing risk with increasing cumulative and average daily GC dose for all outcomes other than glaucoma, hypertension, and GI perforations or bleeding (P < 0.05).

CONCLUSION

Patients with RA had an increased incidence of GC-related AEs. Increasing cumulative and average daily GC doses were found to be associated with an increasing risk of developing an AE.

Perceived stress and well-being in UK and Australian dental hygiene and dental therapy students

INTRODUCTION

This study aimed to explore United Kingdom (UK) and Australian (Aus) dental hygiene and dental therapy students' (DHDTS) perception of stress and well-being during their undergraduate education. Upon qualification, DHDTS in the UK register as dental therapists (DT), and in Australia, they register as Oral Health Therapists (OHT).

MATERIALS AND METHODS

A questionnaire was distributed to years 1, 2 and 3 DHDTS at the University of Portsmouth Dental Academy (UPDA) in the UK and La Trobe Rural Health School in Australia. The questionnaire consisted of 5 well-used measurement instruments which included the following: Dental Environment Stress questionnaire (DES); Depression Anxiety Stress Scales (DASS-21); Scales of Psychological Well-Being (SPWB); Valuing Questionnaire (VQ); and the Adult Hope Scale (AHS) to collect data on students' perception of levels of stress and well-being.

RESULTS

A response rate of 58% (UK) and 55% (Australia) was achieved. Clinical factors and academic work were perceived as stressful for DHDTS in both the UK and Australia. The Australian DHDTS-perceived stress in the educational environment was significantly higher (P < .002) than the UK DHDTS. The majority of respondents reported levels of depression, anxiety and stress to be within the normal-to-moderate range. All students reported high levels of positive well-being, with no significant differences between the 2 groups.

CONCLUSIONS

DHDTS in the UK and Australia identified sources of stress within their undergraduate education, but also perceived themselves as positively functioning individuals.

Risk Associated with Cumulative Oral Glucocorticoid Use in Patients with Giant Cell Arteritis in Real-World Databases from the USA and UK

INTRODUCTION

Treatment of giant cell arteritis (GCA) involves immediate initiation of high-dose glucocorticoid therapy with slow tapering of the dose over many months. Chronic exposure to glucocorticoids is associated with serious comorbidities. The objective of this analysis was to determine the glucocorticoid exposure and risk of glucocorticoid-related adverse events (AEs) in real-world patients with GCA.

METHODS

Data from the Truven Healthcare MarketScan^® database (from January 1, 2000, to June 30, 2015) and the Clinical Practice Research Datalink (CPRD; from January 1, 1995, to August 31, 2013) were used to retrospectively analyze patients aged ≥ 50 years with GCA in the USA and UK, respectively. Outcomes included oral glucocorticoid use (cumulative prednisone-equivalent exposure), glucocorticoid-related AEs and the association of AE risk with glucocorticoid exposure over 52 weeks.

RESULTS

Of the 4804 patients in the US MarketScan database and 3973 patients in the UK CPRD database included, 71.3 and 74.6% were women and mean age was 73.4 and 73.0 years, respectively. Median starting glucocorticoid dose and cumulative glucocorticoid dose at 52 weeks were 20-50 mg/day and 4000-4800 mg, respectively. The most frequent glucocorticoid-related AEs were hypertension and eye, bone health, and glucose tolerance conditions. In the first year after diagnosis, the likelihood of any glucocorticoid-related AE was significantly increased for each 1 g increase in cumulative glucocorticoid dose in the US and UK cohorts (odds ratio [95% CI], 1.170 [1.063, 1.287] and 1.06 [1.03, 1.09], respectively; P < 0.05 for both). Similar trends were observed for the risk of glucocorticoid-related AEs over full follow-up (mean, USA: 3.9 years, UK: 6.3 years).

CONCLUSIONS

In real-world patients with GCA, increased cumulative glucocorticoid exposure was associated with an increased risk of glucocorticoid-related AEs.

FUNDING

F. Hoffmann-La Roche Ltd. Plain language summary available for this article.

Perceived stress and well-being among dental hygiene and dental therapy students

Aims To explore dental hygiene and dental therapy students' (DHDTS') perception of stress and well-being during their undergraduate education and establish base-line data for further studies of this group of dental professionals.Subjects and methods A questionnaire was distributed to Years 1, 2 and 3 DHDTS and final year outreach dental students (DS) (as a comparison group), at the University of Portsmouth Dental Academy (UPDA), during summer 2015. Data were collected on students' perception of levels of stress and well-being. Statistical analyses were undertaken using SPSS software. Mann-Whitney U tests with Bonferroni corrections were used and the level for a statistically significant difference was set at p <0.002.Results A response rate of 81% (DHDTS) and 85% (DS) was achieved. Clinical factors and academic work were perceived as stressful for both DHDTS and DS, with no significant difference between the groups. The majority of respondents reported levels of depression, anxiety, and stress to be within the normal range. All students reported high levels of positive well-being, with DHDTS scoring significantly higher than DS in the dimensions of personal growth, purpose in life, self-acceptance and positive relations with others (p <0.002).Conclusions DHDTS and DS identified sources of stress within their undergraduate education, but also perceived themselves as positively-functioning individuals.

Making concrete construals mindful: a novel approach for developing mindfulness and self-compassion to assist weight loss

Research on the usefulness of mindfulness and self-compassion for dieting has focused on meditative practices. However, meditation can be difficult to maintain, especially while dieting. Thus, the present research attempted to induce mindfulness and self-compassion by using food diaries that required the participant to either focus on concrete (i.e. how they are eating) construals or abstract (i.e. why they are eating) construals. The concrete construals were expected to increase mindfulness and self-compassion, as well as decrease avoidance and negative thoughts (which would further aid the development of mindfulness and self-compassion). Study 1 found that mindfulness and self-compassion mediated the inverse relationship of avoidance and negative thoughts with weight loss. Study 2 showed that concrete construal diaries increased mindfulness and self-compassion, decreased avoidance and negative thoughts, and supported weight loss significantly more than the abstract construal diaries. Study 3, then, compared the concrete construal diaries with a mindful self-compassionate meditation programme. There was no difference in weight loss at the end of the intervention, but at a three-month follow-up, the diaries performed better at weight maintenance. Thus, the concrete construal diaries may promote mindfulness and self-compassion and potentially promote long-term weight loss.

Non-steroidal anti-inflammatory drug use and cervical cancer risk: a case-control study using the Clinical Practice Research Datalink

PURPOSE

Non-steroidal anti-inflammatory drugs (NSAIDs) have many anticarcinogenic properties via the inhibition of cyclooxygenase 2 (COX-2). Only one study, a cohort study examining risk of all cancers, investigated their role in cervical cancer with inconsistent findings between non-aspirin NSAIDs and aspirin. The aim of this study was to further investigate NSAID/aspirin use and cervical cancer risk.

METHODS

Using the United Kingdom Clinical Practice Research Datalink, 724 women diagnosed with cervical cancer between 1 January, 1995 and December 2010 were compared to 3479 women (without cervical cancer) matched on year of birth and general practice. Conditional logistic regression analysis adjusted for smoking, sexually transmitted infections, HRT and contraceptive use, was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for cervical cancer risk among users of any oral NSAIDs, non-aspirin NSAIDs and aspirin, as assessed from primary care prescribing data.

RESULTS

Excluding the year prior to diagnosis, there was no association in adjusted analyses between ever vs. never use of an NSAID (OR 0.92, 95% CI 0.77-1.09), non-aspirin NSAID (OR 0.95, 95% CI 0.80-1.13) or low-dose aspirin (OR 1.07, 0.80-1.44) and cervical cancer risk. In analysis of daily defined doses, there was no association with cervical cancer risk comparing the highest users to non-users of NSAIDs (OR 0.98, 95% CI 0.69-1.39) or non-aspirin NSAIDs (OR 1.00, 95% CI 0.70-1.43) or low-dose aspirin (OR 1.04, 95% CI 0.59-1.81).

CONCLUSION

This large historical cohort study found no evidence of an association between non-aspirin NSAID or aspirin use and cervical cancer risk.

Non-steroidal anti-inflammatory drug and aspirin use and the risk of head and neck cancer

BACKGROUND

Evidence for non-steroidal anti-inflammatory drugs (NSAIDs) preventing head and neck cancer (HNC) is inconclusive; however, there is some suggestion that aspirin may exert a protective effect.

METHODS

Using data from the United States National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, we examined the association between aspirin and ibuprofen use and HNC.

RESULTS

Regular aspirin use was associated with a significant 22% reduction in HNC risk. No association was observed with regular ibuprofen use.

CONCLUSION

Aspirin may have potential as a chemopreventive agent for HNC, but further investigation is warranted.

Environmental, lifestyle, and familial/ethnic factors associated with myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are characterized by overproduction of mature functional blood cells and are often associated with an acquired genetic mutation of Janus Kinase 2(V617F). The etiology of MPNs remains unknown. The aim of this article was to review and collate all known published data investigating environmental and lifestyle factors associated with MPNs. Medline, Embase, PubMed, Cochrane, and Web of Science were systematically searched using terms for MPNs and observational study designs to identify studies investigating the risk factors for MPNs published before March 2010. Of 9,156 articles identified, 19 met the selection criteria. Although the studies exhibited heterogeneity, in case definitions, study design, and risk factors investigated, several themes emerged. A strong association was found with Jewish descent, and with a family history of MPNs. Autoimmune conditions, specifically Crohn's disease, were more common in patients with MPNs. Certain occupational groups were significantly associated with MPNs including occupations with potential exposure to benzene and/or petroleum. Blood donation was associated with an increased risk of polycythemia vera specifically. The vast heterogeneity in studies identified as part of this review suggests that large scale systematic assessment of etiological factors associated with MPNs is warranted.

Non-steroidal anti-inflammatory drug and aspirin use and the risk of head and neck cancer: a systematic review

BACKGROUND

Use of non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with a reduced risk of several cancers. This is thought to be through the inhibitory action on the cyclooxygenase (COX) enzyme, COX-2. Evidence for NSAIDs preventing head and neck cancer (HNC) is conflicting. We conducted a systematic literature review to investigate the association between NSAID/aspirin use and risk of head and neck cancer (HNC).

METHODOLOGY

MEDLINE, EMBASE, PubMed, Cochrane Library, and Web of Science were systematically searched using terms for NSAIDs/aspirin, HNC, and observational/intervention study designs to identify studies published by December 2009.

RESULTS

Of 9,268 articles identified, two population-based prescribing database studies and three case-control studies met the selection criteria. The studies investigated different HNC sites. Only one study found a significant protective association of aspirin use with HNC risk (OR 0.75, 95% CI 0.58-0.96), and one showed a significantly increased risk of oral/oropharyngeal cancer with non-low-dose aspirin NSAID use (OR 3.5, 95% CI 1.8-6.7). Many of the studies identified lacked information on important confounding factors.

CONCLUSION

No definitive conclusion on the effect of NSAIDs/aspirin on HNC risk was possible. Aspirin may protect against HNC, although further robust large-scale studies are required to clarify any possible association.

Phylogenetic analyses and molecular epidemiology of European salmonid alphaviruses (SAV) based on partial E2 and nsP3 gene nucleotide sequences

Sequence data were generated for portions of the E2 and nsP3 genes of 48 salmonid alphaviruses from farmed Atlantic salmon (AS), Salmo salar L., and rainbow trout (RT), Oncorhynchus mykiss (Walbaum), in marine and freshwater environments, respectively, from the Republic of Ireland, Northern Ireland, England, Scotland, Norway, France, Italy and Spain between 1991 and 2007. Based on these sequences, and those of six previously published reference strains, phylogenetic trees were constructed using the parsimony method. Trees generated with both gene segments were similar. Clades corresponding to the three previously recognized subtypes were generated and in addition, two further new clades of viruses were identified. A single further strain (F96-1045) was found to be distinct from all of the other strains in the study. The percentage of nucleotide divergence within clades was generally low (0-4.8% for E2, 0-6.6% for nsP3). Interclade divergence tended to be higher (3.4-19.7% for E2, 6.5-28.1% for nsP3). Based on these results and using current SAV terminology, the two new clades and F96-1045 were termed SAV subtypes 4, 5 and 6, respectively. SAV4 contained AS strains from Ireland and Scotland, while SAV5 contained only Scottish AS strains. Recently identified SAV strains from RT in Italy and Spain were shown to belong to SAV2. In addition, marine AS strains belonging to SAV2 were identified for the first time. Analysis of the origin of several clusters of strains with identical E2 and nsP3 sequences strongly support horizontal transmission of virus between farms and aquaculture companies. Evidence in support of vertical transmission was not found.

Elevated plasma adiponectin in humans with genetically defective insulin receptors

CONTEXT

Adiponectin has been suggested to play a role in the etiopathogenesis of at least some forms of insulin resistance, in part based on a strong correlation between plasma levels of adiponectin and measures of insulin sensitivity.

OBJECTIVE

The objective of the study was to establish whether this relationship is maintained at extreme levels of insulin resistance.

DESIGN/SETTING

This was a cross-sectional study in a university teaching hospital of subjects recruited from the United Kingdom and the United States.

PARTICIPANTS

Participants included 75 subjects with a range of syndromes of severe insulin resistance and 872 nondiabetic controls.

OUTCOME MEASURES

Fasting plasma insulin, adiponectin, and leptin were measured.

RESULTS

Unexpectedly, subjects with mutations in the insulin receptor, despite having the most severe degree of insulin resistance, had elevated plasma adiponectin [median 24.4 mg/liter; range 6.6-36.6 (normal adult range for body mass index 20 kg/m(2) = 3-19 mg/liter)], whereas all other subjects had low adiponectin levels (median 2.0 mg/liter; range 0.12-11.2). Plasma leptin in all but one subject with an insulin receptoropathy was low or undetectable [median 0.5 ng/ml; range 0-16: normal adult range for body mass index of < 25 kg/m(2) = 2.4-24.4 (female) and 0.4-8.3 ng/ml (male)].

CONCLUSIONS

We conclude that the relationship between plasma adiponectin and insulin sensitivity is complex and dependent on the precise etiology of defective insulin action and that the combination of high plasma adiponectin with low leptin may have clinical utility in patients with severe insulin resistance as a marker of the presence of a genetic defect in the insulin receptor.

Observations of mercury-containing aerosols

In situ analyses with a laser ionization mass spectrometer have shown that a large fraction of aerosols in the bottom few kilometers of the stratosphere contain small amounts of mercury (1). Electron microscopy of particles collected near the tropopause has also detected mercury. The distribution of mercury onto many particles, including those less than 20 nm in diameter, indicates that the mercury is from local condensation of mercury compounds onto particles rather than transport of mercury-rich aerosols from surface sources. Although the results are only semiquantitative, they suggest that most of the mercury in the lower stratosphere is converted into the particulate phase. Mercury-containing particles were present at both middle latitudes and the tropics in two seasons. There is therefore good reason to believe that particulate mercury above the tropopause is global and could affect the atmospheric lifetime of mercury. There are indications that bromine and/ or iodine may be involved in the conversion of mercury from the gas to particle phase. Measurements at altitudes below 5 km did not find mercury in any particles despite sampling some particles that clearly originated in the stratosphere. This indicates that the particulate mercury from the lower stratosphere may be volatile enough to evaporate or decompose once particles reach warmer temperatures.

Phylogeographic evidence for the existence of an ancient biogeographic barrier: the Isthmus of Kra Seaway

Biogeographic boundaries are characterised by distinct faunal and floral assemblages restricted on either side, but patterns among groups of taxa often vary and may not be discrete. Historical biogeography as a consequence, while providing crucial insights into the relationship between biological diversity and earth history, has some limitations. Patterns of intraspecific molecular variation, however, may show unambiguous evidence for such historical divides, and can be used to test competing biogeographic hypotheses (often based on the dispersal-vicariance debate). Here, we utilise this method to test the hypothesis that a major biogeographic transition zone between the Sundaic and Indochinese biotas, located just north of the Isthmus of Kra in SE Asia, is the result of Neogene marine transgressions that breached the Isthmus in two locations for prolonged periods of time (>1 million year duration). Phylogeographic analyses of a freshwater decapod crustacean, the giant freshwater prawn Macrobrachium rosenbergii, strongly supports the historical existence of the more northerly postulated seaway. Results presented here highlight the power of utilising intraspecific molecular variation in testing biogeographical hypotheses.

Longitudinal study of MRS metabolites in Rasmussen encephalitis

This study analyses the evolution of metabolite changes in an 8-year-old boy with focal Rasmussen encephalitis. Five MRI examinations, including magnetic resonance spectroscopy (MRS) were performed over 9 months. Following complex partial status, T2-weighted imaging showed transient dramatic signal increase in the left superior temporal gyrus and mesial temporal structures. Subsequent scans showed resolution of the swelling and signal normalization, with development of slight focal atrophy. MRS after status showed a reduction in N-acetylaspartate, total creatine and trimethylamines. Subsequent scans showed complete resolution of these metabolite abnormalities, followed later by development of further abnormal metabolite values. Lactate and glutamine/glutamate were elevated after status. After surgery, ex vivo high-field (1)H and (31)P MRS confirmed metabolite abnormalities (elevated choline and decreased aspartate, N-acetylaspartate, [(1)H]glutamate together with altered [(31)P]phospholipid ratios. These findings suggested active disease process in the anterior region of the excised superior temporal gyrus. We conclude that Rasmussen encephalitis is a combination of progressive encephalitic damage and fluctuating seizure effects, in which neuronal injury and recovery can occur. MRS measurements at a single time point should consider the fluctuating metabolite profile related to seizure activity.

Particle Formation by Ion Nucleation in the Upper Troposphere and Lower Stratosphere

Unexpectedly high concentrations of ultrafine particles were observed over a wide range of latitudes in the upper troposphere and lower stratosphere. Particle number concentrations and size distributions simulated by a numerical model of ion-induced nucleation, constrained by measured thermodynamic data and observed atmospheric key species, were consistent with the observations. These findings indicate that, at typical upper troposphere and lower stratosphere conditions, particles are formed by this nucleation process and grow to measurable sizes with sufficient sun exposure and low preexisting aerosol surface area. Ion-induced nucleation is thus a globally important source of aerosol particles, potentially affecting cloud formation and radiative transfer.

Recent strategies in the search for new anti-influenza therapies

Influenza is a highly contagious, acute upper respiratory tract disease caused by influenza virus, a member of the Orthomyxoviridae family. The viral particles have two surface antigens, haemagglutinin and sialidase (neuraminidase) that extensively decorate the surface of the virus and have been implicated in viral attachment and fusion, and the release of virion progeny, respectively. The receptor for haemagglutinin is the terminal sialic acid residue of host cell surface sialyloligosaccharides, while sialidase catalyses the hydrolysis of terminal sialic acid residues from sialyloligosaccharides. Extensive crystallographic studies of both these proteins have revealed that the residues that interact with the sialic acid are strictly conserved. Therefore, these proteins make attractive targets for the design of drugs to halt the progression of the virus. Recent successful efforts in the search for new cures for influenza have led to the development of three clinically-useful anti-influenza drugs. All three are potent, selective inhibitors of influenza virus A and B sialidase. Strategies for the development of haemagglutinin inhibitors have also been devised.

Formulations and processing of yogurt affect the microbial quality of carbonated yogurt

Carbonation, flavor, culture type, pH, and storage time were varied to investigate the effects of these variables and their interactions on the growth of both typical and nontypical yogurt cultures and some contaminating bacteria. Two types of yogurt cultures (YC-470 and YC-180) were used as the source of typical yogurt bacteria, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. In addition, Lactobacillus acidophilus (LA-K) and Bifidobacterium longum ATCC 15707 were added as nontypical yogurt cultures to make sweetened low fat (1%) Swiss-style plain, strawberry, and lemon yogurts. Samples were incubated at 43 degrees C until pH values of 5.0 or 4.2 were reached. Strawberry yogurts at low (4.2) and high (5.0) pHs were divided into three portions, which were separately inoculated with contaminating bacteria, Bacillus licheniformis ATCC 14580, Escherichia coli ATCC 11775, and Listeria monocytogenes Scott A. After incorporation of carbon dioxide (1.10 to 1.27 volume of CO2 gas dissolved in water), the yogurt was stored at 4 degrees C for a 90-d period. Carbon dioxide did not affect the growth of typical or nontypical yogurt bacteria. Also, CO2 did not inhibit the growth of undesirable microorganisms. In general, low levels of CO2 did not affect the bacterial population in yogurt. The microflora of yogurt were influenced by culture type, pH, flavor type, and storage time or their interactions.

The detection of large HNO3-containing particles in the winter Arctic stratosphere

Large particles containing nitric acid (HNO3) were observed in the 1999/2000 Arctic winter stratosphere. These in situ observations were made over a large altitude range (16 to 21 kilometers) and horizontal extent (1800 kilometers) on several airborne sampling flights during a period of several weeks. With diameters of 10 to 20 micrometers, these sedimenting particles have significant potential to denitrify the lower stratosphere. A microphysical model of nitric acid trihydrate particles is able to simulate the growth and sedimentation of these large sizes in the lower stratosphere, but the nucleation process is not yet known. Accurate modeling of the formation of these large particles is essential for understanding Arctic denitrification and predicting future Arctic ozone abundances.

Preliminary 1H NMR investigation of sialic acid transfer by the trans-sialidase from Trypanosoma cruzi

1H NMR spectroscopy has been used to investigate the transfer of sialic acid from sialic acid donor molecules to acceptor molecules using the trans-sialidase from Typanosoma cruzi. It is clearly demonstrated that NMR spectroscopy is an efficient and powerful means of monitoring the trans-sialidase promoted transfer of sialic acid from donor to acceptor.

The conformational and biological analysis of a cyclic anti-obesity peptide from the C-terminal domain of human growth hormone

The three-dimensional solution structure of antiobesity drug (AOD), a 15-residue, disulfide-bonded, cyclic peptide, cyclo(6,13)-H2N-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe-OH, derived from the C-terminal domain of the human growth hormone (hGH) (residues 177-191) was determined using two-dimensional 1H NMR spectroscopy. AOD stimulates lipolysis and inhibits lipogenesis, in vitro, in rodent, porcine and human adipose tissues. These biological effects suggest that AOD is a potential therapeutic candidate for the treatment of obesity. Conformational studies of AOD were conducted in aqueous solution and in water/dimethylsulfoxide mixtures. In general, spectral quality was superior in the water/ dimethylsulfoxide mixtures. The cyclic region of AOD in water/dimethylsulfoxide adopts type I beta-turns at residues Ser8-Val9-Glu10-Gly11 and Ser12-Cys13-Gly14-Phe15, each preceded by loop-like structures. Comparison of the conformation of this peptide with residues 177-191 in the native hGH protein X-ray crystal structure indicates that the synthetic peptide retains some structural similarity to the intact protein. This study provides evidence that the C-terminal region of hGH is a specific functional domain of the multifunctional hGH protein.

Synthesis and evaluation of C-9 modified N-acetylneuraminic acid derivatives as substrates for N-acetylneuraminic acid aldolase

Several C-9 modified N-acetylneuraminic acid derivatives have been synthesised and evaluated as substrates of N-acetylneuraminic acid aldolase. Simple C-9 acyl or ether modified derivatives of N-acetylneuraminic acid were found to be accepted as substrates by the enzyme, albeit being transformed more slowly than Neu5Ac itself. 1H NMR spectroscopy was used to evaluate the extent of the enzyme catalysed transformation of these compounds. Interestingly, the chain-extended Neu5Ac derivative 16 is not a substrate for N-acetylneuraminate lyase and behaves as an inhibitor of the enzyme.

Viscoelasticity of randomly branched polymers in the vulcanization class

We report viscosity, recoverable compliance, and molar mass distribution for a series of randomly branched polyester samples with long linear chain sections between branch points. Molecular structure characterization determines tau=2.47+/-0.05 for the exponent controlling the molar mass distribution, so this system belongs to the vulcanization (mean-field) universality class. Consequently, branched polymers of similar size strongly overlap and form interchain entanglements. The viscosity diverges at the gel point with an exponent s=6.1+/-0.3, that is significantly larger than the value of 1.33 predicted by the branched polymer Rouse model (bead-spring model without entanglements). The recoverable compliance diverges at the percolation threshold with an exponent t=3.2+/-0.2. This effect is consistent with the idea that each branched polymer of size equal to the correlation length stores k(B)T of elastic energy. Near the gel point, the complex shear modulus is a power law in frequency with an exponent u=0.33+/-0.05. The measured rheological exponents confirm that the dynamic scaling law u=t/(s+t) holds for the vulcanization class. Since s is larger and u is smaller than the Rouse values observed in systems that belong to the critical percolation universality class, we conclude that entanglements profoundly increase the longest relaxation time. Examination of the literature data reveals clear trends for the exponents s and u as functions of the chain length between branch points. These dependencies, qualitatively explained by hierarchical relaxation models, imply that the dynamic scaling observed in systems that belong to the vulcanization class is nonuniversal.

Investigation of the stability of thiosialosides toward hydrolysis by sialidases using NMR spectroscopy

[formula: see text] 1H NMR spectroscopy has been used to investigate whether the alpha(2-->6)-linked thiosialoside 3 and the alpha(2-->3)-linked thiosialoside 9 are hydrolyzed in the presence of Vibrio cholerae sialidase. Similarly, the hydrolysis of the O-ketosides Neu5Ac-2-O-alpha-(2-->3)-Gal beta Me (4) and the alpha-(2-->6)-sialyllactoside 7, representing natural alpha(2-->3)- and alpha(2-->6)-linked sialosides, respectively, was investigated. The results of the 1H NMR experiments clearly demonstrate that the thiosialosides are not hydrolyzed by Vibrio cholerae sialidase. As expected, the O-sialosides are hydrolyzed to give N-acetyl-alpha-D-neuraminic acid as the first product of substrate cleavage.

Children's recall 1 or 2 years after an event

In Study 1, children were reinterviewed about an event they had taken part in 2 years earlier when they were 6 years old (M.-E. Pipe & J. C. Wilson, 1994). In Study 2, children were reinterviewed about an event in which they had participated 1 year earlier when they were 6 or 9 years of age (S. Gee & M.-E. Pipe, 1995). Interviews were conducted with or without cue items and distractors, as in the original studies. The amount of information reported in free recall decreased over the 1- or 2-year delays, and for 6-year-olds, there was also a small decrease in accuracy of free recall. Reinstating specific cue items in Study 2 maintained recall when attention was drawn to them, but prompting children led to a decrease in accuracy. Whereas information repeated across interviews was highly accurate, information reported for the first time at the long delays was not.

Children's recall 1 or 2 years after an event

In Study 1, children were reinterviewed about an event they had taken part in 2 years earlier when they were 6 years old (M.-E. Pipe & J. C. Wilson, 1994). In Study 2, children were reinterviewed about an event in which they had participated 1 year earlier when they were 6 or 9 years of age (S. Gee & M.-E. Pipe, 1995). Interviews were conducted with or without cue items and distractors, as in the original studies. The amount of information reported in free recall decreased over the 1- or 2-year delays, and for 6-year-olds, there was also a small decrease in accuracy of free recall. Reinstating specific cue items in Study 2 maintained recall when attention was drawn to them, but prompting children led to a decrease in accuracy. Whereas information repeated across interviews was highly accurate, information reported for the first time at the long delays was not.

Platelet-derived growth factor in human brain tumors

This paper initially reviews ligand and receptor systems for the PDGF family and the signalling systems they use as well as their role in neural developments. It then describes the putative role of this family in astrocytoma, meningioma, and pituitary adenoma pathogenesis. Potential therapies with receptor antagonists or dominant negative mutants are discussed in the final sections.

Crystal structure of vipoxin at 2.0 A: an example of regulation of a toxic function generated by molecular evolution

Vipoxin is the main toxic component in the venom of the Bulgarian snake Vipera ammodytes meridionalis, the most toxic snake in Europe. Vipoxin is a complex between a toxic phospholipase A2 (PLA2) and a non-toxic protein inhibitor. The structure is of genetic interest due to the high degree of sequence homology (62%) between the two functionally different components. The structure shows that the formation of the complex in vipoxin is significantly different to that seen in many known structures of phospholipases and contradicts the assumptions made in earlier studies. The modulation of PLA2 activity is of great pharmacological interest, and the present structure will be a model for structure-based drug design.

Reciprocal regulation of the early promoter region of bacteriophage HP1 by the Cox and Cl proteins

We have identified a transcriptional switch at the early promoter region of bacteriophage HP1. This switch controls the transcription of the early lytic operon from the P(R1) and P(R2) promoters and the transcription of the lysogenic operon from the P(L) promoter. The start sites of the three promoters were mapped, and using a chloramphenicol acetyl transferase assay, we have investigated the levels of transcription from the promoters in the absence or in the presence of two phage-encoded transcription factors: HP1 Cox and HP1 Cl. The HP1 Cox protein repressed the production of P(L) transcripts 30-fold, while the HP1 Cl protein repressed lytic transcription at least 70-fold. Binding sites for HP1 Cox and Cl were identified in the early promoter region; mutations of these sites eliminated transcriptional repression. In addition, a mutant Cl protein was isolated which is temperature sensitive for repression. Taken together, these data demonstrate the reciprocal regulation of a transcriptional switch in which the actions of the two phage-encoded proteins at the phage early promoters determine the choice between lytic and lysogenic growth.

A conformational study of the human and rat encephalitogenic myelin oligodendrocyte glycoprotein peptides 35-55

Myelin oligodendrocyte glycoprotein (MOG), is considered an important central-nervous system-specific target autoantigen for primary demyelination in autoimmune diseases like multiple sclerosis. We have recently demonstrated that MOG or its derived peptide, MOG-(35-55)-peptide, are able to produce in animals, clinicopathologic signs that mimic multiple sclerosis. The rat MOG sequence spanning amino acids 35-55 [rMOG-(35-55)-peptide] differs from the human sequence [hMOG-(35-55)-peptide] by a single amino acid substitution, i.e. Pro42-->Ser. Mice injected with rMOG-(35-55)-peptide showed severe inflammation and demyelination throughout the central nervous system but, interestingly, mice injected with hMOG-(35 -55)-peptide showed only a few foci of mild inflammation with no demyelination. Circular dichroism and nuclear magnetic resonance spectroscopy have been used to structurally characterise the bioactive peptides hMOG-(35-55)-peptide and rMOG-(35-55)-peptide. In 0.1 M K2HPO4/KOH, 90% H2O/D2O solutions, these derived peptides have been shown, by NMR spectroscopy, to adopt detectable levels of short-range structure in equilibrium with unfolded conformers. On addition of 2,2,2-trifluoro-(2H3)ethanol, rMOG-(35-55)-peptide and hMOG-(35-55)-peptide adopt folded structures which have nuclear Overhauser enhancements characteristic of a poorly defined alpha-helix over residues 44-51. There are some indications of secondary structure also evident in the N-terminal region of rMOG-(35-55)-peptide. CD spectroscopy has revealed that in aqueous solution both peptides are unfolded but in 2.2.2-trifluoroethanol and, at micellar concentrations of sodium dodecyl sulfate, rMOG-(35-55)-peptide and, to a lesser extent, hMOG-(35-55)-peptide adopt helical conformations. In contrast, at non-micellar concentrations of SDS rMOG-(35-55)-peptide and hMOG-(35-55)-peptide adopt, according to CD spectroscopy, a beta-structure indicating that the peptides change conformation depending on the microenvironment of the amino acids.

Catalysis by a new sialidase, deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm), initially forms a less stable alpha-anomer of 3-deoxy-D-glycero-D-galacto-nonulosonic acid and is strongly inhibited by the transition state analogue, 2-deoxy-2, 3-didehydro-D-glycero-D-galacto-2-nonulopyranosonic acid, but not by 2-deoxy-2,3-didehydro-N-acetylneuraminic acid

Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and 1H NMR spectroscopy. Vmax/Km values determined for synthetic and natural substrates of KDNase Sm reveal that 4-methylumbelliferyl-KDN (KDNalpha2MeUmb, Vmax/Km = 0.033 min-1) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2, 3-didehydro-2,3-dideoxy-D-galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of KDNase Sm (Ki = 7.7 microM versus Km = 42 microM for KDNalpha2MeUmb). 2-Deoxy-2, 3-didehydro-N-acetylneuraminic acid and 2-deoxy-2, 3-didehydro-N-glycolylneuraminic acid are known to be strong competitive inhibitors for bacterial sialidases such as Arthrobacter ureafaciens sialidase; however, KDNase Sm activity is not significantly inhibited by these compounds. This observation suggests that the hydroxyl group at C-5 is important for recognition of the inhibitor by the enzyme. Reversible addition of water molecule (or hydroxide ion) to the reactive sialosyl cation, presumably formed at the catalytic site of KDNase Sm, eventually gives rise to two different adducts, the alpha- and beta-anomers of free 3-deoxy-D-glycero-D-galacto-nonulosonic acid. 1H NMR spectroscopic studies clearly demonstrate that the thermodynamically less stable alpha-form is preferentially formed as the first product of the cleavage reaction and that isomerization rapidly follows, leading to an equilibrium mixture of the two isomers, the beta-isomer being the major species at equilibrium. Therefore, we propose that KDNase Sm catalysis proceeds via a mechanism common to the known exosialidases, but the recognition of the substituent at C-5 by the enzyme differs.

Patterns of differentiation among wild rabbit populations Oryctolagus cuniculus L. in arid and semiarid ecosystems of north-eastern Australia

Feral rabbit populations in Australia have generally been managed using localized control procedures. While these procedures may result in local extinctions, persistence of populations will depend on the probability of recolonization. Genetic markers developed using temperature gradient gel electrophoresis (TGGE) combined with heteroduplex analysis (HA) of mitochondrial DNA (mtDNA) were used to characterize the degree of subdivision and extent of gene flow within and among rabbit populations distributed over large distances (up to 1000 km) in southern Queensland (QLD) and north-west New South Wales (NSW), Australia. TGGE analyses revealed significant heterogeneity in mtDNA control region haplotype frequencies. From heterogeneity chi 2 tests, it was evident that the differentiation observed was largely attributable to five sites which were located in the semiarid eastern region, whereas haplotype frequencies were homogeneous throughout the arid western region. These results suggest that there are independent population systems within the study area. The extent of gene flow among local populations within each system is related to the spatial configuration of acceptable habitat patches and the persistence of the populations is determined by the probability of recolonization following local extinction. These data suggest that to provide better overall control of rabbit populations, different management strategies may be necessary in arid and semiarid ecosystems. In arid south-west QLD and north-west NSW, where extensive gene flow occurs over large distances, rabbit populations should be managed at a regional level. In semiarid eastern QLD, where gene flow is restricted and populations are more isolated, localized control procedures may provide effective short-term relief. These results indicate that in nonequilibrium systems with patchy distribution of individuals, the interpretation of migration rate from estimates of gene flow obtained using existing genetic models must include an understanding of the spatial and temporal scales over which population processes operate.

A 1H NMR investigation of the hydrolysis of a synthetic substrate by KDN-sialidase from Crassostrea virginica

The mechanism of hydrolysis of 4-methylumbelliferyl 3-deoxy-D-glycero-alpha-D-galacto-2-nonulopyranosidonic acid (KDN alpha 2MeUmb, 4) by KDN-sialidase isolated from the hepatopancreas of the oyster Crassostrea virginica has been monitored by 1H NMR spectroscopy. The results of these experiments reveal that KDN-sialidase catalyses the hydrolysis of the synthetic substrate KDN alpha 2MeUmb, with initial release of alpha-D-KDN. This is consistent with an overall mechanism for the hydrolysis which proceeds with retention of anomeric configuration. These results agree with earlier NMR studies of other N-acetylneuraminic acid-recognising sialidases from both viral and bacterial sources.

The binding of carbon monoxide and nitric oxide to leghaemoglobin in comparison with other haemoglobins

Haemoglobins have the ability to discriminate between oxygen and other diatomic molecules. To further understanding of this process the X-ray crystal structures of carbonmonoxy and nitrosyl-leghaemoglobin have been determined at 1.8 A resolution. The ligand geometry is discussed in detail and the controversial issue of bent versus linear carbon monoxide binding is addressed. The bond angle of 160 degrees for CO-leghaemoglobin is in conflict with recent spectroscopy results on myoglobin but is consistent with angles obtained for myoglobin X-ray crystal structures. In contrast to the numerous carbon monoxide studies, very little stereochemical information is available for the nitric oxide adduct of haemoglobin. This is provided by the X-ray structure of NO-leghaemoglobin, which conforms to expected geometry with an Fe-NO angle of 147 degrees and a lengthened iron-proximal histidine bond. Thus crystallographic evidence is given for the predicted weakening of this bond on the binding of nitric oxide.

Limited genetic differentiation among wild Oryctolagus cuniculus L. (rabbit) populations in arid eastern Australia

A systems approach is necessary for effective control of feral rabbit (Oryctolagus cuniculus L.) populations in the arid environments of Australia. Localized control procedures may result in local extinctions, but the persistence of the overall population will depend on the probability of recolonization, and hence, the degree of isolation of each local population unit. Genetic markers obtained using allozyme electrophoresis, temperature gradient gel electrophoresis (TGGE) and heteroduplex analysis (HA) were used to characterize the degree of structuring and extent of gene flow among rabbit populations in arid Queensland, Australia. Allozyme allele frequency data showed that there was no significant differentiation among sites (average FST = 0.005) and no isolation-by-distance or environmental discontinuity effects. TGGE/HA results also revealed no significant differentiation in mitochondrial DNA Control Region haplotype frequencies among sites and low interpopulation nucleotide divergence estimates (NST = 0.013). Therefore, rabbit populations exhibited a high degree of gene flow over large geographical areas (1600 km2) and were essentially a single panmictic unit. Unpredictable environmental conditions together with the spatial configuration of habitats which possess different probabilities of extinction may have resulted in repeated local extinctions followed by recolonization and homogenizing gene flow. These data suggest that current rabbit control strategies based on individual warren management may not achieve effective control in arid Queensland.

The crystal structures of trout Hb I in the deoxy and carbonmonoxy forms

We have determined the X-ray crystallographic structure of trout Hb I in both the deoxy and carbonmonoxy forms to resolution limits of 2.3 angstroms and 2.5 angstroms, respectively. The overall fold of the molecule is highly similar to that of human HbA despite the low level of sequence identity between these proteins. Trout Hb I is unusual in displaying almost no pH dependence of oxygen binding affinity, and (at most) very weak interactions with heterotropic effector ligands such as organic phosphates. Comparison of the two quaternary states of the protein indicates how such effects are minimised and how the low-affinity T state of the protein is stabilised in the absence of heterotropic interactions.

The structure of deoxy- and oxy-leghaemoglobin from lupin

The leghaemoglobins have oxygen affinities 11 to 24 times higher than that of sperm whale myoglobin, due mainly to higher rates of association. To find out why, we have determined the structures of deoxy- and oxy-leghaemoglobin II of the lupin at 1.7 A resolution. Results confirm the general features found in previous X-ray analyses of this protein. The unique feature that has now emerged is the rotational freedom of the proximal histidine. In deoxy-leghaemoglobin the imidazole oscillates between two alternative orientations, eclipsing either the lines N1-N3 or N2-N4 of the porphyrin; in oxy-leghaemoglobin it is fixed in a staggered orientation. The iron atom moves from a position 0.30 A from the plane of the pyrrole nitrogen atoms in deoxy- to a position in the plane in oxy-leghaemoglobin while the Fe-<N> bond distance remains constant at 2.02 A. The Fe-O-O angle is 152 degrees, as in human haemoglobin. The oxygen is hydrogen-bonded to the distal histidine at N epsilon 2-O1 and N epsilon 2-O2 distance of 2.95 A and 2.68 A, respectively. The porphyrin is ruffled equally in deoxy- and oxy-leghaemoglobins, due to rotations of the pyrrols about the N-Fe-N bonds, causing the methine bridges to deviate by up to 0.32 A from the mean porphyrin plane. The only feature capable of accounting for the high on-rate of the reaction with oxygen are the mobilities of the proximal histidine and distal histidine residues in deoxy-leghaemoglobin. The eclipsed positions of the proximal histidine in deoxy-leghaemoglobin maximize steric hindrance with the porphyrin nitrogen atoms and minimize pi-->p electron donation, while its staggered position in oxy-leghaemoglobin reverses both these effects. Together with the oscillation of the imidazole between the two orientations, these two factors may reduce the activation energy for the reaction of leghaemoglobin with oxygen. The distal histidine is in a fixed position in the haem pocket in the crystal, but must be swinging in and out of the pocket at a high rate in solution to allow the oxygen to enter.

The Synthesis and N.M.R. Investigation of a Methyloxime Derivative of N-Acetylneuraminic Acid

The synthesis of a novel 4-modified N-acetylneuraminic acid analogue and its structural characterization by n.m.r. spectroscopy are reported.

A determination of the solution conformation of the nonmammalian tachykinin eledoisin by NMR and CD spectroscopy

The nonmammalian tachykinin eledoisin was investigated by use of CD and two-dimensional NMR techniques. In aqueous solution the peptide is conformationally averaged, but on addition of 50% trifluoroethanol (TFE) or sodium dodecyl sulfate (SDS) it adopts an alpha-helical structure. In TFE/H2O and SDS, residues 6-10 of eledoisin show more conformational order than the terminal regions, which undergo dynamic fraying. A possible turn in the N-terminal "address" region, the putative receptor recognition site of the peptide, is detected by NMR spectroscopy but appears to undergo substantial conformational averaging. The NMR data indicate that the helical central core of eledoisin is better defined in the micellar environment than in TFE; however, partial unfolding via 3(10) intermediates occurs in both cases. The conformational preference for SDS-bound eledoisin was examined by three-dimensional structure calculations using NMR-derived distance information in simulated annealing calculations.

In Situ Observations of Aerosol and Chlorine Monoxide After the 1991 Eruption of Mount Pinatubo: Effect of Reactions on Sulfate Aerosol

Highly resolved aerosol size distributions measured from high-altitude aircraft can be used to describe the effect of the 1991 eruption of Mount Pinatubo on the stratospheric aerosol. In some air masses, aerosol mass mixing ratios increased by factors exceeding 100 and aerosol surface area concentrations increased by factors of 30 or more. Increases in aerosol surface area concentration were accompanied by increases in chlorine monoxide at mid-latitudes when confounding factors were controlled. This observation supports the assertion that reactions occurring on the aerosol can increase the fraction of stratospheric chlorine that occurs in ozone-destroying forms.

Chemical Loss of Ozone in the Arctic Polar Vortex in the Winter of 1991-1992

In situ measurements of chlorine monoxide, bromine monoxide, and ozone are extrapolated globally, with the use of meteorological tracers, to infer the loss rates for ozone in the Arctic lower stratosphere during the Airborne Arctic Stratospheric Expedition II (AASE II) in the winter of 1991-1992. The analysis indicates removal of 15 to 20 percent of ambient ozone because of elevated concentrations of chlorine monoxide and bromine monoxide. Observations during AASE II define rates of removal of chlorine monoxide attributable to reaction with nitrogen dioxide (produced by photolysis of nitric acid) and to production of hydrochloric acid. Ozone loss ceased in March as concentrations of chlorine monoxide declined. Ozone losses could approach 50 percent if regeneration of nitrogen dioxide were inhibited by irreversible removal of nitrogen oxides (denitrification), as presently observed in the Antarctic, or without denitrification if inorganic chlorine concentrations were to double.

Rapid filtration assays for protein kinase C activity and phorbol ester binding using multiwell plates with fitted filtration discs

In the conventional approach protein kinase activity and phorbol ester binding associated with protein kinase C (PKC) are measured by initially incubating samples in either test tubes or multiwell plates, followed by filtration of the terminated reaction mixture using either a manifold filtration device or a cell harvester. Here we report a method in which both the incubations and filtrations necessary for the determination of either protein kinase activity or phorbol ester binding are carried out in the same multiwell plate with fitted filtration discs made of polyvinylidene difluoride (Durapore membrane). Due to the very low binding of protein to these filters, there is no interference caused by these filters during the incubation period of the assays. The drawback with these filters compared to commonly used cellulose acetate membrane filters is that they retain less of the phosphate acceptor substrate histone H1 (only 15%) if filtered and washed with standard 5% trichloroacetic acid. However, this can be overcome by increasing the trichloroacetic acid concentration to 25% during filtration. For phorbol ester binding determinations, the samples are incubated with [3H]phorbol 12,13-dibutyrate in the microwells, the ligand bound PKC is adsorbed onto DEAE-Sephadex beads, and the beads then are filtered and washed in the same microwells. Furthermore, this multiwell filtration approach can also be adopted to previously described cytosolic phorbol ester receptor assays, which have the broader conditions for optimal binding to receptors. Durapore membrane filters are found to work well for punching into scintillation vials and there is complete recovery of the radioactivity retained with the filters. In the protein kinase assay the background radioactivity is very low (< 200 cpm) and in the phorbol ester binding assay the nonspecific binding is less than 1%. Thus, these low background values result in at least a fourfold increase in sensitivity for these assays. Since the incubations and filtrations are carried out in the same well without any transfer of the sample, the coefficient of variation in multiple determinations is found to be low. Furthermore, this method is rapid and more convenient for analyzing a larger number of samples than conventional methods which use test tubes, and it is less expensive to set up compared to the automated methods that use a cell harvester.

A New Zealand randomized comparative study of three IUDs (Nova-T, MLCu375, MLAgCu250): 1-, 2- and 3-year results

A randomized comparative study was made in New Zealand of 3 models of copper IUDs, the Nova-T, MLCu375 and MLAgCu250, with interval acceptors. Completing 3 years of use, there were 608 Nova-T (14,011 woman-months), 586 MLCu375 (14,161 woman-months) and 596 MLAgCu250 (14,614 woman-months). At 3 years, loss to follow-up was 5.2% for the Nova-T, 5.1% for the MLCu375 and 4.1% for the MLAgCu250. The Multiloads were significantly easier to insert and were preferred by the operators, as the insertion technique for the Nova-T was complicated. However, the Nova-T was significantly easier to remove. There was one perforation with a Nova-T in a puerperal breastfeeding woman. In the only 2 parameters that are comparable between series, accidental pregnancy and expulsion [1], the Multiloads have been shown to be superior with higher relevant continuation rates. At 3 years, the MLCu375 had a significantly lower accidental pregnancy rate and higher relevant continuation rate. The results obtained with the Nova-T are similar to those of the WHO study [2]. The MLCu375, with its potential for use up to 5 years, has been shown to be the superior device.

A randomized comparative study of three IUDs: Nova-T, MLCu375 and MLAgCu250 in New Zealand: 1-year results

A randomized comparative study was made in New Zealand of three models of copper IUDs, the Nova-T, MLCu375 and MLAgCu250, with interval acceptors. At 1 year, the Multiloads (MLs) had lower net termination rates for accidental pregnancy, expulsion, pain/bleeding, other medical removals and infections (use-related terminations) than the Nova-T. These rates were significantly lower for the MLAgCu250 than the Nova-T for accidental pregnancy, expulsion and infection. The MLCu375 had significantly fewer removals for pain/bleeding and for other medical removals than the Nova-T. The MLAgCu250 had a significantly lower accidental pregnancy rate than the MLCu375. The Multiloads had significantly higher relevant use-related continuation rates than the Nova-T.