Sex-differences in oral anticoagulation therapy in patients hospitalised with atrial fibrillation: a nationwide cohort study

Background

Important disparities in the treatment and outcomes of women and men with atrial fibrillation are well recognized. Whether introduction of direct oral anticoagulants has reduced disparities in treatment is uncertain.

Methods

All patients who had an incident hospitalization from 2010 to 2019 with non-valvular atrial fibrillation in Scotland were included in this cohort study. Community drug dispensing data were used to determine prescribed oral anticoagulation therapy and comorbidity status. Logistic regression modelling was used to evaluate patient factors associated with treatment with vitamin K antagonists and direct oral anticoagulants.

Results

A total of 172,989 patients (48% women [82,833/172,989]) had an incident hospitalization with non-valvular atrial fibrillation in Scotland between 2010 and 2019. The proportion of patients with thromboembolic risk factors (CHA2DS2VASc score >0 in men and >1 in women) treated with oral anticoagulation therapy increased from 36.8% to 66.3% over this 10-year period. By 2019, factor Xa inhibitors accounted for 83.6% of all oral anticoagulants prescribed, while treatment with vitamin K antagonists and direct thrombin inhibitors declined to 15.9% and 0.6%, respectively. Women were less likely to be prescribed any oral anticoagulation therapy compared to men (adjusted odds ratio, aOR 0.68 [95% CI, CI 0.67–0.70]). This disparity was mainly attributed to vitamin K antagonists (aOR 0.68 [95% CI 0.66–0.70]), whilst there was less disparity in use of factor Xa inhibitors between women and men (aOR 0.92 [95% CI 0.90–0.95]). At 1 year following hospitalization with atrial fibrillation, patients not prescribed oral anticoagulation therapy were more likely to have subsequent major adverse cardiovascular events compared to those prescribed with oral anticoagulation therapy (38.8% [15,380/39,608] versus 17.0% [6,761/39,671] in women and 35.2% [12,977/36,868] versus 16.4% [7,395/45,093] in men).

Conclusions

Women with non-valvular atrial fibrillation were significantly less likely to be prescribed vitamin K antagonists compared to men. Most patients admitted to hospital in Scotland with incident non-valvular atrial fibrillation are now treated with factor Xa inhibitors and this is associated with less treatment disparities between women and men.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by the British Heart Foundation through a Clinical Research Training Fellowship (FS/18/25/33454), Intermediate Clinical Research Fellowship (FS/19/17/34172), Senior Clinical Research Fellowship (FS/16/14/32023) and a Research Excellence Award (RE/18/5/34216), and a research grant to NHS Lothian from Bristol Myers Squibb Pharmaceuticals Ltd and Pfizer UK Ltd.

Atrial fibrillation and stroke outcomes in Scotland: real-world evidence from a contemporary, national dataset

Introduction

Atrial Fibrillation (AF) is an important cause of mortality and morbidity. The major risk of AF is stroke, which can be reduced through anticoagulation. The burden of stroke, and AF-related stroke, is particularly high in Scotland. It is often reported that AF-related stroke is associated with poorer outcomes than other stroke types, it is also thought to lead to an increased institutionalisation. Data supporting these observations are historic, but major advances in AF assessment and treatment could have changed outcome patterns. Real world evidence on outcomes, collected at scale, can give a useful measure of contemporary AF stroke outcomes.

Purpose

To assess whether stroke patients, with and without AF on admission, differ in terms of al-cause mortality, recurrence of stroke, and care home admission using contemporary large-scale observational data.

Methods

A retrospective cohort study linking national hospital, prescribing, care home and stroke audit data was conducted. The cohort, comprising patients ≥18 years of age with incident ischemic stroke between 2009 and 2017, was divided into three groups: AF-related stroke prescribed oral anticoagulant (OAC) pre-stroke event (AF-OAC Group); AF-related stroke not prescribed anticoagulant pre-stroke event (AF-noOAC Group); stroke with no prevalent or incident AF and no anticoagulation (comparator) (noAF-noOAC Group). Time-to-event analyses (adjusted for demographic and clinical characteristics) were conducted to estimate hazard ratios for recurrent stroke, all-cause mortality, and care-home admission with a follow-up time of two years.

Results

From a cohort of 64,159 incident ischemic strokes, 4,418 and 15,124 patients with AF were identified for groups AF-OAC and AF-noOAC, respectively. The remaining 44,617 patients belonged to group noAF-noOAC. An increasing number of incident strokes was observed with increasing age in each group up to 80–84 years. The risk of recurrent stroke was significantly greater in groups AF-OAC (HR 1.12 [95% CI 1.08,1.17]) and AF-noOAC (HR 1.05 [95% CI 1.03,1.08]) compared to noAF-noOAC group. An increased risk of all-cause mortality was observed in groups AF-OAC (HR 1.52 [95% CI 1.39,1.66]) and AF-noOAC (HR 1.59 [95% CI 1.51,1.68]) compared to the noAF-noOAC group. Patients in group AF-noOAC were more likely to be discharged to a care home following stroke (HR 1.37 [95% CI 1.23,1.52]) compared to patients in the other groups.

Conclusion

AF-related stroke is associated with poor outcomes, with significantly higher risks of recurrent stroke and all-cause mortality for patients with AF compared to non-AF stroke. Despite advances in AF care, our data suggest there is still potential to prevent a substantial proportion of disabling strokes through better identification and treatment of AF. These results must be interpreted with caution, as data take no account of treatment adherence, dosing or rationale for individual patient level prescribing decisions.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bristol-Myers Squibb Research and Development

Integrating a newly developed BAC-based physical mapping resource for Lolium perenne with a genome-wide association study across a L. perenne European ecotype collection identifies genomic contexts associated with agriculturally important traits

BACKGROUND AND AIMS

Lolium perenne (perennial ryegrass) is the most widely cultivated forage and amenity grass species in temperate areas worldwide and there is a need to understand the genetic architectures of key agricultural traits and crop characteristics that deliver wider environmental services. Our aim was to identify genomic regions associated with agriculturally important traits by integrating a bacterial artificial chromosome (BAC)-based physical map with a genome-wide association study (GWAS).

METHODS

BAC-based physical maps for L. perenne were constructed from ~212 000 high-information-content fingerprints using Fingerprint Contig and Linear Topology Contig software. BAC clones were associated with both BAC-end sequences and a partial minimum tiling path sequence. A panel of 716 L. perenne diploid genotypes from 90 European accessions was assessed in the field over 2 years, and genotyped using a Lolium Infinium SNP array. The GWAS was carried out using a linear mixed model implemented in TASSEL, and extended genomic regions associated with significant markers were identified through integration with the physical map.

KEY RESULTS

Between ~3600 and 7500 physical map contigs were derived, depending on the software and probability thresholds used, and integrated with ~35 k sequenced BAC clones to develop a resource predicted to span the majority of the L. perenne genome. From the GWAS, eight different loci were significantly associated with heading date, plant width, plant biomass and water-soluble carbohydrate accumulation, seven of which could be associated with physical map contigs. This allowed the identification of a number of candidate genes.

CONCLUSIONS

Combining the physical mapping resource with the GWAS has allowed us to extend the search for candidate genes across larger regions of the L. perenne genome and identified a number of interesting gene model annotations. These physical maps will aid in validating future sequence-based assemblies of the L. perenne genome.

Cost-effectiveness of dapagliflozin versus DPP-4 inhibitors as an add-on to Metformin in the Treatment of Type 2 Diabetes Mellitus from a UK Healthcare System Perspective

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic, progressive condition where the primary treatment goal is to maintain control of glycated haemoglobin (HbA1c). In order for healthcare decision makers to ensure patients receive the highest standard of care within the available budget, the clinical benefits of each treatment option must be balanced against the economic consequences. The aim of this study was to assess the cost-effectiveness of dapagliflozin, the first-in-class sodium-glucose co-transporter 2 (SGLT2) inhibitor, compared with a dipeptidyl peptidase-4 inhibitor (DPP-4i), when added to metformin for the treatment of patients with T2DM inadequately controlled on metformin alone.

METHODS

The previously published and validated Cardiff diabetes model was used as the basis for this economic evaluation, with treatment effect parameters sourced from a systematic review and network meta-analysis. Costs, derived from a UK healthcare system perspective, and quality-adjusted life years (QALYs), were used to present the final outcome as an incremental cost-effectiveness ratio (ICER) over a lifetime horizon. Univariate and probabilistic sensitivity analyses (PSA) were carried out to assess uncertainty in the model results.

RESULTS

Compared with DPP-4i, dapagliflozin was associated with a mean incremental benefit of 0.032 QALYs (95% confidence interval [CI]: -0.022, 0.140) and with an incremental cost of £216 (95% CI: £-258, £795). This resulted in an ICER point estimate of £6,761 per QALY gained. Sensitivity analysis determined incremental costs to be insensitive to variation in most parameters, with only the treatment effect on weight having a notable impact on the incremental QALYs; however, there were no scenarios which raised the ICER above £15,000 per QALY. The PSA estimated that dapagliflozin had an 85% probability of being cost-effective at a willingness-to-pay threshold of £20,000 per QALY gained.

CONCLUSIONS

Dapagliflozin in combination with metformin was shown to be a cost-effective treatment option from a UK healthcare system perspective for patients with T2DM who are inadequately controlled on metformin alone.

The cost-effectiveness of dapagliflozin versus sulfonylurea as an add-on to metformin in the treatment of Type 2 diabetes mellitus

AIMS

To assess the cost-effectiveness of dapagliflozin, a sodium-glucose co-transporter-2 (SGLT-2) inhibitor, compared with a sulfonylurea, when added to metformin for treatment of UK people with Type 2 diabetes mellitus inadequately controlled on metformin alone.

METHODS

Clinical inputs sourced from a head-to-head randomized controlled trial (RCT) informed the Cardiff diabetes decision model. Risk equations developed from the United Kingdom Prospective Diabetes Study (UKPDS) were used in conjunction with the clinical inputs to predict disease progression and the incidence of micro- and macrovascular complications over a lifetime horizon. Cost and utility data were generated to present the incremental cost-effectiveness ratio (ICER) for both treatment arms, and sensitivity and scenario analyses were conducted to assess the impact of uncertainty on the final model results.

RESULTS

The dapagliflozin treatment arm was associated with a mean incremental benefit of 0.467 quality-adjusted life years (QALYs) [95% confidence interval (CI): 0.420; 0.665], with an incremental cost of £1246 (95% CI: £613; £1637). This resulted in an ICER point estimate of £2671 per QALY gained. Incremental costs were shown to be insensitive to parameter variation, with only treatment-related weight change having a significant impact on the incremental QALYs. Probabilistic sensitivity analysis determined that dapagliflozin had a 100% probability of being cost-effective at a willingness-to-pay threshold of £20,000 per QALY.

CONCLUSIONS

Dapagliflozin in combination with metformin was shown to be a cost-effective treatment option compared with sulfonylurea from a UK healthcare perspective for people with Type 2 diabetes mellitus who are inadequately controlled on metformin monotherapy.

Living with osteoarthritis: a systematic review and meta-ethnography

OBJECTIVES

To review and synthesize the existing literature on the experience of living with a diagnosis of hip and/or knee osteoarthritis (OA).

METHOD

A systematic review was undertaken using meta-ethnography. A search of both published (AMED, CINAHL, EMBASE, PsychINFO, SportsDisc, MEDLINE, Cochrane Clinical Trials Registry, PubMed) and unpublished/trial registry databases [World Health Organization (WHO) International Clinical Trials Registry Platform, Current Controlled Trials, the United States National Institute of Health Trials Registry, National Institute for Health Research (NIHR) Clinical Research Portfolio Database] was undertaken from their inception to 5 June 2013.

RESULTS

Thirty-two studies formed the meta-ethnography of the lived experiences of people with OA. In total, 1643 people with OA were sampled, the majority diagnosed with knee OA. The evidence base was weak to moderate in quality. The majority of studies indicated that people viewed living with OA negatively. Four key factors influenced their attitudes to the condition: the severity of their symptoms; the impact of these symptoms on their functional capability; their attitude towards understanding their disease; and their perceptions of other people's beliefs towards their disease.

CONCLUSIONS

The current literature suggests that greater knowledge of the pathology of OA, management of symptoms, promotion of functional activity for patients and their family/friends networks, and understanding to better inform OA patient's role in society are all important elements that affect a person's attitude to OA. By better understanding these factors during future consultations, clinicians may forge stronger relationships with their patients to more effectively manage this long-term disabling condition.

February asthma outbreaks in NSW: a case control study

OBJECTIVES

To investigate individual factors associated with an asthma outbreak among children aged one to 14 years in Sydney in February 1999.

METHODS

A case control study was undertaken with cases (n=92) defined as all children admitted to Sydney Children's Hospital for asthma in February 1999. Unmatched controls (n=76) were all children admitted for asthma in the previous three months. We obtained information by a structured telephone survey of parents. Logistic regression analyses were used to determine odds ratios for risk factors for hospital admission.

RESULTS

Mean age for hospital admission of 4.7 years for cases and 4.4 years for controls. The presence of one or more siblings reduced the risk of admission during an asthma outbreak (OR=0.59, 95% CI 0.37 to 0.93). Children with older siblings aged 10 to 14 years were also less likely to be admitted (OR=0.3, 95% CI 0.12 to 0.74). An age effect was observed. Other demographic, clinical and environmental characteristics, including smoking, were not associated with admission during the outbreak.

CONCLUSIONS

The main findings of this study are the protective effect of siblings and an age-dependent effect in risk of hospital admission during an asthma outbreak. These findings are consistent with an infective cause of the outbreak.

IMPLICATIONS

Children without siblings, particularly older siblings, appear to be at highest risk of hospital admission during an asthma outbreak. Environmental and other factors need to be examined to further explain the episodicity of such outbreaks and to determine means of predicting and preventing future episodes.

'Scaling-up' in emergencies: British NGOs after Hurricane Mitch

This article examines research on NGO 'scaling-up' in a disaster context and links it to a broader discussion on whether scaling-up is a useful concept for understanding NGO processes in an emergency. Using concepts of scaling-up from development literature, research findings from a study of the responses of British NGOs to Hurricane Mitch in Central America are presented. The article assesses the extent and type of scaling-up that occurred, constraints faced by the agencies and the impact of scaling-up on support to partners. Broader issues relating to scaling-up post-Mitch are also explored. The conclusion suggests that while the concept of scaling-up is useful, the tendency for its use to refer to organisational growth has limited a wider understanding and evaluation of the role of Northern NGOs in humanitarian crises.

Serological approaches to subtyping of HIV-1 in injecting drug users in Russia: evidence of subtype homogeneity at the main sites of the epidemic

The aim of this study was to develop and evaluate a simple V3 peptide-based enzyme immunoassay (PEIA) for large-scale serotyping of HIV-1 specimens derived from injecting drug users (IDUs) in the Russian Federation. Two synthetic peptides were evaluated, named P1 (RKSIHIGPGRAFYATGD) and P2 (RTSVRIGPGQVFYKTGD), in an PEIA on 63 HIV-1 IDUs sera for which genotypes had been determined by heteroduplex mobility assay (HMA) and sequencing. The sensitivities of P1 (subtype B) and P2 (subtype A) were 87% and 75% respectively. Specificity of the assay was 100% for both peptides, with 100% predictive values of a monoreactive positive test for both peptides. Using the PEIA with peptides P1 and P2, we have serotyped 375 of 477 serum samples derived from IDUs in 4 main sites of the HIV-1 epidemic in Russia. The results demonstrated a high level of subtype homogeneity in all regions studied. In 3 of 4 territories, Tver' (n=345), and Rostov-on-Don (n=61) regions, and Krasnodar Kray (n=27), 100% of typable sera were found to belong to env subtype A. On the other hand, all specimens serotyped in the Kaliningrad region (n=38) belonged to env subtype B, and there is strong evidence that the recombinant gagAenvB virus which has caused the largest outbreak of HIV-1 in Russia is located in this region. At the present time another parental strain with gagBenvB genotype is of minor importance in the IDUs HIV-1 epidemic in Russia.

Receiving shadows: governance and liminality in the night-time economy

This paper focuses upon the emergence of the night-time economy both materially and culturally as a powerful manifestation of post-industrial society. This emergence features two key processes: firstly a shift in economic development from the industrial to the post-industrial; secondly a significant orientation of urban governance involving a move away from the traditional managerial functions of local service provision, towards an entrepreneurial stance primarily focused on the facilitation of economic growth. Central to this new economic era is the identification and promotion of liminality. The State's apparent inability to control these new leisure zones constitutes the creation of an urban frontier that is governed by commercial imperatives.

The pharmacology of latent inhibition as an animal model of schizophrenia

The nature of the primary symptoms of schizophrenia and our lack of knowledge of its underlying cause both contribute to the difficulty of generating convincing animal models of schizophrenia. A more recent approach to investigating the biological basis of schizophrenia has been to use information processing models of the disease to link psychotic phenomena to their neural basis. Schizophrenics are impaired in a number of experimental cognitive tasks that support this approach, including sensory gating tasks and models of selective attention such as latent inhibition (LI). LI refers to a process in which noncontingent presentation of a stimulus attenuates its ability to enter into subsequent associations, and it has received much attention because it is widely considered to relate to the cognitive abnormalities that characterise acute schizophrenia. Several claims have been made for LI having face and construct validity for schizophrenia. In this review of the pharmacological studies carried out with LI we examine its claim to predictive validity and the role of methodological considerations in drug effects. The data reviewed demonstrate that facilitation of low levels of LI is strongly related to demonstrated antipsychotic activity in man and all major antipsychotic drugs, both typical and atypical, have been shown to potentiate LI using a variety of protocols. Very few compounds without antipsychotic activity are active in this model. In contrast, disruption of LI occurs with a wide range of drugs and the relationship with psychotomimetic potential is less clear. Although reversal of disrupted LI has also been used as a model for antipsychotic acticity, mostly using amphetamine-induced disruption, insufficient studies have been carried out to evaluate its claim to predictive validity. However, like facilitation, it is sensitive to both typical and atypical antipsychotic agents. The data we have reviewed here demonstrate that facilitation of LI and, perhaps to a lesser extent, reversal of disrupted LI fulfil the criteria for predictive validity.

A phase I trial in HIV negative healthy volunteers evaluating the effect of potent adjuvants on immunogenicity of a recombinant gp120W61D derived from dual tropic R5X4 HIV-1ACH320

Thirty healthy HIV negative volunteers were randomised to receive 200 micrograms of rgp120W61D in either: 3D-MPL and QS21, with an oil and water emulsion (SBAS-2) (13); or 3D-MPL and QS21 (SBAS-1) (11); or alum (six). Immunizations were given at 0, 4 and 28 weeks and 23 (77%) participants completed the schedule. Adverse events were more frequent (P < 0.001) and more severe (P < 0.001) in the SBAS-2 group. Binding antibodies to the homologous rgp120W61D were detected after the first immunisation only in those receiving SBAS-1 and SBAS-2, were maximal after the third immunization in all three groups, and persisted to week 84 only in the novel adjuvant groups. These differences were significant (p = 0.02). Neutralising antibodies to TCLA-strains of HIV-1 were observed after the second immunization in all three groups, were maximal after the third immunization, but did not neutralise homologous or heterologous PBMC derived primary HIV-1 isolates. Proliferative T-cell responses to rgp120W61D were maximal after the second immunization and reached very high values in the SBAS-2 group. HIV-1 specific CD8+ MHC Class I restricted cytotoxic T-lymphocytes were not seen in a subset of participants tested at a single timepoint. SBAS-2 with rgp120W61D induced antibody titres as high as those seen in HIV infection, but the quality of the antibodies remained different in that there was no evidence of primary isolate neutralisation. Although cell-mediated immunity was enhanced by SBAS-2 in terms of lymphoproliferative responses, HIV-1 specific CD8+ cytotoxicity was not demonstrated.

Immunisation coverage in Australian children: a systematic review 1990-1998

The Australian Childhood Immunisation Register (ACIR) commenced operation in January 1996 and provides a comprehensive database of children's immunisations in Australia. The ACIR enables implementation of an immunisation recall and reminder system and improved surveillance and reporting of immunisation coverage. Before the introduction of the ACIR, the methods used in assessing coverage varied widely in design and quality, with few studies measuring coverage at national or statewide level. This is a systematic review of the scope and reliability of estimates of immunisation coverage available in Australia from 1990 to 1998. A total of 108 studies were identified of which 51 were classified as higher quality based on a range of criteria including whether they had a response rate of 50% or better.

Comparison of the antibody repertoire generated in healthy volunteers following immunization with a monomeric recombinant gp120 construct derived from a CCR5/CXCR4-using human immunodeficiency virus type 1 isolate with sera from naturally infected individuals

We have characterized sera from healthy volunteers immunized with a monomeric recombinant gp120 (rgp120) derived from a CCR5/CXCR4 (R5X4)-using subtype B isolate of human immunodeficiency virus type (HIV-1), HIV-1W61D, in comparison to sera from long-term HIV-1-infected individuals, using homologous reagents. Sera from vaccinees and HIV-1 positive subjects had similar binding titers to native monomeric rgp120W61D and showed a similar titer of antibodies inhibiting the binding of soluble CD4 (sCD4) to rgp120W61D. However, extensive peptide binding studies showed that the overall pattern of recognition of vaccinee and HIV-1-positive sera is different, with vaccinee sera displaying a wider and more potent recognition of linear V1/V2 and V3 domain epitopes. Neutralization of homologous HIV-1W61D or heterologous HIV-1M2424/4 peripheral blood mononuclear cell (PBMC)-derived virus lines by vaccinee sera could be achieved, but only after adaptation of the viruses to T-cell lines and was quickly lost on readaptation to growth in PBMC. Sera from HIV-positive individuals were able to neutralize both PBMC-grown and T-cell line-adapted viruses. Interestingly, rgp120W61D was recognized by monoclonal antibodies previously shown to neutralize primary HIV-1 isolates. The use of very potent adjuvants and R5X4 rgp120 led to an antibody response equivalent in binding activity and inhibition of binding of sCD4 to gp120 to that of HIV-positive individuals but did not lead to the induction of antibodies capable of neutralizing PBMC-grown virus.

Distinct recognition of non-clade B human immunodeficiency virus type 1 epitopes by cytotoxic T lymphocytes generated from donors infected in Africa

We present detailed studies of human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte (CTL) responses to clade A or C HIV type 1 in three donors infected in East Africa. We define several novel non-clade B CTL epitopes, including some restricted by HLA alleles common in Africans. Although cross-clade CTL recognition of these epitopes does occur, recognition can also be highly clade specific.

Australia's notifiable diseases status, 1997. Annual report of the National Notifiable Diseases Surveillance System

In 1997 there were 89,579 notifications to the National Notifiable Diseases Surveillance System. A notable feature of 1997 was the pertussis outbreak which peaked towards the end of the year and resulted in 10,668 cases being notified. The highest number of notifications received was for hepatitis C (unspecified) with 19,692 notifications; this is the first year for which data have been reported for New South Wales and South Australia for this disease category. The number of measles cases rose after the low number reported in 1996 but is still well below the number reported in the outbreak years of 1993 and 1994. Rubella notifications continued to decline in 1997. Notifications of Haemophilus influenzae type b appeared to have stabilised at a low rate, having declined markedly after introduction of the conjugated vaccine in 1992. The number of cases of campylobacteriosis remained steady after having risen for several years. Notifications of hepatitis A cases rose considerably, much of this being due to one outbreak in New South Wales. The number of cases of salmonellosis rose while shigellosis numbers dropped slightly. Notifications for chlamydial infection and gonococcal infection continued to rise, whilst those for syphilis continued to fall.

Serotyping of HIV type 1 infections: definition, relationship to viral genetic subtypes, and assay evaluation. UNAIDS Network for HIV-1 Isolation and Characterization

V3 serotyping refers to a system based on binding of antibody in patient sera to V3-loop peptides derived from HIV-1 env genetic subtypes. The V3x serotype represents reactivity of serum from an HIV-1-infected patient (regardless of viral genetic subtype), which reacts preferentially to a V3 peptide derived from the X subtype sequence. We have classified HIV-1 serotypes, determined the relationship between the HIV-1 V3 serotypes and viral genetic subtypes in a large study (n = 125), and evaluated the performance of three different V3 peptide-binding assays. Seven HIV-1 V3 serotypes were identified: A, B, B-Br, B-Th, C, D, and E. Serotypes B-Br and B-Th represent sera that react specifically to peptides derived from Brazilian B (B-Br, GWGR) and Thai B (B-Th, GPGQ) strains. The HIV-1 V3 B, C, and E serotypes correlated closely with their viral env genetic subtypes; 19-26 of 32 B sera (59-79%), 3-4 of 4 C sera (75-100%), and 19-22 of 23 E sera (83-96%) were identified as serotypes B, C, and E, respectively. In contrast, two major V3 serotypes were classified in A sera: A (14-18 of 36 [40-50%]) and C (12-19 of 36 [33-54%]). Similarly, two major V3 serotypes were classified in D sera: B (6-10 of 20 [30-50%]) and D (9-12 of 20 [45-60%]). Serotyping of subtype E sera showed the best concordance with genetic subtypes by all assays. Overall, HIV-1 V3 serotyping produced consistent results among three laboratories. However, HIV-1 V3 serotypes do not distinguish all HIV-1 genetic subtypes. The relative biological significance of the V3 serotypes remains to be elucidated.

Disruption of latent inhibition in the rat by the 5-HT2 agonist DOI: effects of MDL 100,907, clozapine, risperidone and haloperidol

Latent inhibition (LI), a measure of the ability to learn to ignore irrelevant stimuli, is disrupted in acute schizophrenics and in rats treated with amphetamine; antipsychotics prevent amphetamine disruption of LI in rats. The 5-HT2A/C agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) has hallucinogenic properties in humans, and evidence suggests that 5-HT2 antagonism is an important component of atypical antipsychotic activity. Therefore, the ability of DOI to disrupt LI in rats was tested, and the ability of clinically-used and putative antipsychotics to reverse DOI disruption of LI was assessed. The method consisted of four phases. After habituation to the apparatus, thirsty rats underwent preexposure to a tone stimulus 24 h prior to two tone-shock conditioning trials. LI was demonstrated at testing (an additional 24 h later) by reduced lick suppression during tone presentation. When administered at the preexposure phase only, DOI disrupted LI. However, when administered at both preexposure and conditioning phases, DOI did not disrupt LI except at the highest dose, where lick suppression itself was also disrupted. Therefore, disruptive effects of DOI on LI are not easily dissociated from state-dependent learning effects. Additional experiments demonstrated that haloperidol, clozapine, risperidone, and the selective 5-HT2A antagonist MDL 100,907 prevented the disruptive effects of DOI on LI when administered at preexposure only. These results agree with findings that these compounds can also prevent other behavioral effects of DOI. Further experiments will be required to explore the possible involvement of state-dependent learning effects in the present results. However, if the disruptive effects of DOI on LI are due to an influence on attentional processes rather than state-dependent learning, this procedure may have potential as a method for detection of antipsychotic activity.

Acquisition of conditioned inhibition in rats is impaired by ablation of serotoninergic pathways

The effects of chronically ablating the serotoninergic inputs to various regions of the rat brain on the ability to solve a feature-negative discrimination was measured. After intracerebroventricular administration of the specific neurotoxin 5,7-dihydroxytryptamine, the rats exhibited an impaired capacity to solve such a discrimination, irrespective of whether auditory or visual stimuli were used. Further behavioural analysis revealed that this effect was not due to a reduced capacity to form excitatory associations, since both groups responded equally to reinforced stimuli. By contrast, the lesion more likely resulted in a failure to endow the non-reinforced stimuli with inhibitory properties. This suggestion was supported by the observation that, in a retardation test, the conditioned inhibitor aroused less inhibition in the lesioned group than in vehicle-injected controls. Furthermore, the conditioned inhibitor failed to pass a summation test in lesioned animals, again indicating that their hampered ability to master the discrimination was the result of an impairment in the formation of inhibitory associations. It is concluded that destruction of central 5-hydroxytryptamine-containing pathways impairs the functioning of brain areas underlying inhibitory associative learning.

Serotyping HIV type 1 by antibody binding to the V3 loop: relationship to viral genotype. WHO Network for HIV Isolation and Characterization

We have investigated whether peptides representing the HIV-1 principal neutralization domain (V3) can be used as antigens in antibody-binding assays to predict the genotypes of the subjects' virus. Serum samples collected from HIV-1-infected subjects from the four WHO-sponsored vaccine evaluation sites (Uganda, Rwanda, Thailand, and Brazil) were characterized by antibody binding to a panel of synthetic V3 peptides that were derived from the consensus sequences of the V3 region of the HIV-1 subgroups according to the env phylogenetic analysis (A-E). An indirect V3 peptide-binding assay was used for primary screening, and a V3 peptide antigen-limiting ELISA was then used as a secondary assay to discriminate cross-reactivity if the screening assay was equivocal. In general, V3 peptide serology could predict HIV-1 genotypes. In sera for which the genotype of the virus was known, peptide assays could predict the correct genotype in approximately 90% of cases for genotypes A, B, C, and E; Ugandan sera of genotype D were more broadly reactive. There was considerable serological cross-reactivity between some HIV-1 genotypes, in particular between A and C, and, to a lesser extent, B and D subtypes. Owing to polymorphism at the crown of the V3 loop, an additional B peptide (B') was required to type Brazilian B genotype sera. These simple assays may help facilitate the determination and distribution of HIV-1 genotypes circulating in populations.

Use of real-time B-mode ultrasound for pregnancy diagnosis and measurement of fetal growth rate in captive bottlenose dolphins (Tursiops truncatus)

Real-time ultrasonography was used to detect pregnancy in 4 captive bottle-nose dolphins. Pregnancy was readily confirmed from around the 4th month of gestation by imaging fetal fluids and fetal movement. Periodic examination permitted monitoring of the viability of the fetuses by observation of their heart beat and movement, and serial measurements of skull diameter (occipito-frontal axis) and thoracic diameter was possible. A growth curve for these measurements was plotted.

The effects of acute and repeated administration of various antidepressant drugs on clonidine-induced hypoactivity in mice and rats

Small doses of clonidine produce hypoactivity in mice and rats, probably by stimulating pre-synaptic alpha 2-adrenoceptors in the brain. When mice were injected with desmethylimipramine (DMI, 5 mg/kg) before clonidine it attenuated the hypoactivity, while pretreatment with amitriptyline (5 mg/kg) or mianserin (5 mg/kg) potentiated this behaviour. In rats, desmethylimipramine (20 mg/kg) inhibited and mianserin (5 mg/kg) potentiated the clonidine-induced hypoactivity. Amitriptyline (20 mg/kg), however, had no effect on this behaviour in rats. Mice were also given repeated injections of these 3 antidepressant drugs (5 mg/kg twice daily for 14 days) and were tested with clonidine 12 and 60 hr after the final treatment. At 12 hr desmethylimipramine and amitriptyline both attenuated the hypoactivity responses while the reduction by mianserin was marginal (potency DMI greater than amitriptyline greater than mianserin). At 60 hr, however, amitriptyline and mianserin both decreased the clonidine-induced responses while the attenuation by desmethylimipramine was slight (potency amitriptyline congruent to mianserin greater than DMI). In rats, repeated injections of desmethylimipramine (20 mg/kg), administered twice daily for 14 days, attenuated the clonidine-induced hypoactivity 12 hr after the final treatment and this effect persisted for at least 72 hr. Furthermore, the degree of inhibition of the behavioural responses did not correlate with plasma concentrations of desmethylimipramine and persisted after disappearance of the drug from plasma. In conclusion, these data suggest that after repeated injection, desmethylimipramine, amitriptyline and mianserin all produce an adaptive decrease in the function of central alpha 2-adrenoceptors but the time course of this change differs with the individual antidepressant drug administered.