The evolution of human influenza viruses.

The evolution of influenza viruses results in (i) recurrent annual epidemics of disease that are caused by progressive antigenic drift of influenza A and B viruses due to the mutability of the RNA genome and (ii) infrequent but severe pandemics caused by the emergence of novel influenza A subtypes to which the population has little immunity. The latter characteristic is a consequence of the wide antigenic diversity and peculiar host range of influenza A viruses and the ability of their segmented RNA genomes to undergo frequent genetic reassortment (recombination) during mixed infections. Contrasting features of the evolution of recently circulating influenza AH1N1, AH3N2 and B viruses include the rapid drift of AH3N2 viruses as a single lineage, the slow replacement of successive antigenic variants of AH1N1 viruses and the co-circulation over some 25 years of antigenically and genetically distinct lineages of influenza B viruses. Constant monitoring of changes in the circulating viruses is important for maintaining the efficacy of influenza vaccines in combating disease.

Coronary artery bypass graft outcome: the Trinidad and Tobago experience

The study is a retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in hospital and intermediate term follow up results. The mean age of patients was 59 ñ 10 years and 78 percent male. Sixty-four percent were of East Indian descent, whereas, 16 percnt were of Africian descent. Forty-eight percent of the patients were hypertensive, 46 percent were diabetic, 33 percent had hyperlipidaemia, 20 percent had a recent history of cigarette smoking and 16 percent were obese. Sixty-five percent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5 percent of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 ñ 15 percent. Wall motion abnormalities were seen in 67 pecent of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91 percent, 78 percent, 54 percent and 5 percent, respectively. Many patients (67 percent) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 ñ 0.8 days. In hospital mortality was 3.9 percent (8/205). THe most frequent post operative complicaton was haemorrhage (2.6 percent). Acute renal failure occurred in 2.1 percent; pulmonary collapse, 1.6 percent; 1 percent and cardiac arrest , 1 percent. Both sternal wound infections and systemic sepsis occurred in 0.5 percent. Intermediate term follow-up data were obtained for 92 percent (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow up period, 7 patients (3.4 percent) died. Angina severity was reduced from a mean CCS score of 2.61 ñ 0.95 before CABG ot 1.22 ñ 0.55 at the time of follow up (p<0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.(Au)

Coronary artery bypass graft outcome: the Trinidad and Tobago experience

The study is retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in-hospital and intermediate-term follow-up results. The mean age of patients was 59 +/- 10 years and 78 were male. Sixty-four per cent were of East Indian descent, whereas 16 were of African descent. Forty-eight per cent of the patients were hypertensive, 46 were diabetic, 33 had hyperlipidaemia, 20 had a recent history of cigarette smoking and 16 were obese. Sixty-five per cent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5 of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 +/- 15. Wall motion abnormalities were seen in 67 of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91, 78, 54 and 5, respectively. Many patients (67) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 +/- 0.8 days. In-hospital mortality was 3.9 (8/205). The most frequent post-operative complication was haemorrhage (2.6). Acute renal failure occurred in 2.1; pulmonary collapse, 1.6; stroke, 1 and cardiac arrest, 1. Both sternal wound infections and systemic sepsis occurred in 0.5. Intermediate-term follow-up data were obtained for 92 (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow-up period, 7 patients (3.4) died. Angina severity was reduced from a mean CCS score of 2.61 +/- 0.95 before CABG to 1.22 +/- 0.55 at the time of follow-up (p < 0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.

Reported anxieties concerning intimate parenting in women sexually abused as children.

OBJECTIVE: The study had two aims: (1) To investigate whether mothers with a history of contact child sexual abuse were anxious about the intimate aspects of parenting compared with a clinical comparison group. (2) To determine if there was any relationship between the mother's anxieties and the kind of parenting they recalled receiving themselves. METHOD: Two groups of mothers in mental health out-patient care were interviewed; 34 women with a history of contact child sexual abuse and 29 women with no history of sexual abuse. They completed the Intimate Aspects of Parenting Questionnaire, The Parenting Stress Index (Short form) The Parental Bonding Instrument and The General Health Questionnaire-28. The index group also completed a sexual abuse history questionnaire. RESULTS: Mothers with a history of child sexual abuse were significantly more anxious about intimate aspects of parenting than the comparison group. They also reported significantly more overall stress as parents. The index group recalled that their own parents were significantly less caring and that their fathers more controlling than the comparison group. A low score on Father Care was significantly associated with concerns about intimate parenting, but not with total parenting stress. By contrast, a low score on Mother Care was significantly associated with higher stress experienced as a parent, but not as strongly with anxieties about intimate parenting. CONCLUSIONS: Mothers with a history of contact child sexual abuse who attend mental health services are often worried that their normal parenting behaviors may be inappropriate or seen as such by other people. These anxieties seem associated with their history of childhood sexual abuse.

Coronary artery bypass graft outcome: the Trinidad and Tobago experience.

The study is retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in-hospital and intermediate-term follow-up results. The mean age of patients was 59 +/- 10 years and 78% were male. Sixty-four per cent were of East Indian descent, whereas 16% were of African descent. Forty-eight per cent of the patients were hypertensive, 46% were diabetic, 33% had hyperlipidaemia, 20% had a recent history of cigarette smoking and 16% were obese. Sixty-five per cent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5% of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 +/- 15%. Wall motion abnormalities were seen in 67% of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91%, 78%, 54% and 5%, respectively. Many patients (67%) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 +/- 0.8 days. In-hospital mortality was 3.9% (8/205). The most frequent post-operative complication was haemorrhage (2.6%). Acute renal failure occurred in 2.1%; pulmonary collapse, 1.6%; stroke, 1% and cardiac arrest, 1%. Both sternal wound infections and systemic sepsis occurred in 0.5%. Intermediate-term follow-up data were obtained for 92% (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow-up period, 7 patients (3.4%) died. Angina severity was reduced from a mean CCS score of 2.61 +/- 0.95 before CABG to 1.22 +/- 0.55 at the time of follow-up (p < 0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.

Reduction in episodes of self harm/harm to others in severely mentally ill population through assertive outreach.

This article aims to apply the process of clinical governance to the management of patients with a major mental illness, living in the community, with a history of self harm and/or harm to others; and to design an early warning system to drive rapid intervention if patients miss a clinic appointment. This follows the recommendations of good clinical practice for this vulnerable group.

Use of nebulized adrenaline to aid expulsion of intra-nasal foreign bodies in children.

Foreign bodies in the noses of children may often be expelled by simple nose blowing. Success of this manoeuvre depends on how firmly the object is lodged, and on the co-operation and skill of the child. Attempts at direct removal using instruments frequently result in the patient becoming distressed and resort to general anaesthesia is sometimes required. This short communication describes a series of cases in which nebulized adrenaline helped loosen firmly impacted foreign bodies, thereby facilitating removal, minimizing upset for the child, and avoiding anaesthetic risk.

Epitope mapping of cross-reactive monoclonal antibodies specific for the influenza A virus PA and PB2 polypeptides.

Characterization of the epitopes recognized by 21 monoclonal antibodies (MAbs) specific for the influenza A virus PA (13 MAbs) and PB2 (8 MAbs) polypeptides (Bárcena et al. (1994) J. Virol. 68, 6900-6909) raised against denatured polypeptides produced in E. coli is described. MAbs were characterized by: (1) competitive binding ELISAs; (2) mapping of the protein regions that specify their binding sites; and (3) analyses of their ability to recognize the corresponding viral protein in a number of viral isolates. Five and three non-overlapping antigenic areas were defined by the anti-PA and anti-PB2 MAbs, respectively. Five of the anti-PA MAbs recognized antigenic determinants located within the amino-terminal 157 amino acids of the PA protein, and 6 others reacted strongly with a PA fragment comprising the first 236 amino acids. All 8 anti-PB2 antibodies reacted strongly with a polypeptide fragment containing amino acids 1-113 of the PB2 protein. Analyses of the reactivities of 4 anti-P antibodies with 23 influenza A virus reference strains isolated over a period of 61 years and recovered from humans, pigs, birds and horses, showed that the epitopes were conserved among all viral isolates. The application of these antibodies as research and diagnostic tools is discussed.

Antigenic and genetic characterization of current influenza strains.

Annually the influenza centre receives more than 1000 virus isolates from around the world to monitor the changing pattern of viruses causing influenza throughout the year. These are characterized antigenically using both polyclonal and monoclonal antibodies and selected viruses are subjected to closer scrutiny by nucleotide sequence analyses of their HA genes. This information is used in making the annual recommendation of vaccine composition. As in the last 15 years, influenza A viruses of both H3N2 and H1N1 subtypes and influenza B viruses have been isolated during the recent influenza season. Outbreaks in the northern hemisphere were largely caused by influenza B viruses which are similar to the B/Panama/45/90 reference strain. The proportion of influenza A increased later in the season and was predominantly of the H3N2 subtype, viruses similar to the recent A/Beijing/32/92 variant being most prevalent. The observed changes taking place will be discussed in the context of recent trends.

Analysis of murine antibody responses to baculovirus-expressed human immunodeficiency virus type 1 envelope glycoproteins.

An analysis of the humoral immunogenicity of a candidate AIDS vaccine (VaxSyn) in a murine model system is presented. Sera taken from a panel of mice immunized with the immunogen were analysed for their ability to bind a panel of gp120-representing peptides and limited reactivity to known sites of immunological interest was observed. Monoclonal antibodies (MAbs) were characterized as binding to a more restricted variety of regions on gp120 including C1, V2, V4 and the C terminus. A tetrazolium-based cytocidicity assay was used and shown to be an effective and objective method for the screening of human immunodeficiency virus (HIV)-neutralizing activity in large numbers of samples. None of the MAbs characterized in this study neutralize HIV-1 reference strains. The significance of these findings in view of previous publications is discussed.

Isolation of two H1N2 influenza viruses from swine in France.

Samples collected in 1987 and 1988 in Brittany from influenza-infected swine made it possible to isolate and antigenically characterize two H1N2 recombinant viruses (Sw/France/5027/87 and Sw/France/5550/88). The former virus was cloned and reinoculated to swine to allow reproduction of the disease and reisolation of a strain similar to the original one. The serodiagnostic tests carried out on both the original sera and those from the experimentally infected animals confirmed that the virus was actually type Sw/H1N2.

The immunotargeting approach to adjuvant-independent immunization with influenza haemagglutinin.

By conjugating the bromelain fragment of the influenza virus haemagglutinin (BHA) to a mouse monoclonal antibody specific for a species-crossreactive, framework determinant on class II major histocompatibility complex molecules, the adjuvant-independent immunotargeting approach could be compared with more conventional immunizations involving Freund's complete adjuvant (FCA) and alum, in different species. Both rabbits and ferrets made significant virus-blocking IgG responses to the immunotargeted BHA in the absence of adjuvant, and no adverse reactions were observed with the conjugate immunizations. As measured by enzyme-linked immunosorbent assay, these responses were equal to those observed with alum, and were approximately one-quarter of the level seen with FCA. In terms of influenza virus haemagglutination inhibition, immunotargeting appeared to be more effective than alum, but less effective than FCA. Collectively, the results indicate that immunotargeting may provide a safe and effective alternative to the use of adjuvants in the development of defined subunit vaccines.

Specific structural alteration of the influenza haemagglutinin by amantadine.

Amantadine hydrochloride specifically blocks the release of virus particles from H7 influenza virus infected cells. This appears to be the direct consequence of an amantadine induced change in the haemagglutinin (HA) to its low pH conformation. The effect is indirect and mediated via interaction of the drug with the M2 protein since mutants altered in this component alone are insensitive to amantadine. The timing of drug action, some 15-20 min after synthesis, and its coincidence with proteolytic cleavage indicates that the modifications to HA occur late during transport but prior to insertion into the plasma membrane. Reversal by mM concentrations of amines and 0.1 microM monensin indicates that amantadine action causes a reduction in intravesicular pH which triggers the conformational change in HA. We conclude, therefore, that the function of M2 inhibited by amantadine is involved in counteracting the acidity of vesicular compartments of the exocytic pathway in infected cells and is important in protecting the structural integrity of the acid-sensitive glycoprotein.

Immune recognition of influenza virus haemagglutinin.

Haemagglutinin glycoproteins are the components of influenza virus membranes against which infectivity-neutralizing antibodies are directed. Sequence analysis of natural and laboratory-selected variant haemagglutinins indicates the regions of the molecule recognized by antibodies and by helper T cells; the identity of these regions and the relations between them are discussed.

Influenza A virus enhances IgE-mediated histamine release from human basophil leukocytes. Examination of the effect of viral neuraminidase and haemagglutinin.

Histamine release caused by anti-IgE was examined in leukocyte suspensions from 10 healthy individuals. Influenza A virus was found to enhance the histamine release but did not release histamine per se. When monoclonal antibodies directed against the viral neuraminidase were included in the samples, the potentiating effect of the virus was completely abolished. The same occurred using a neuraminidase inhibitor. However, monoclonal antibodies directed against the viral haemagglutinin also abolished the potentiation. A binding of virus to the basophil cell surface by haemagglutinin therefore seems to be necessary for the viral neuraminidase to cause potentiation of mediator release.

Calculation of whole blood CO2 content.

Currently used methods for calculating whole blood CO2 content from calculated plasma content, measured blood pH, hemoglobin concentration ([Hb]), and O2 saturation yield materially different results. In this study the constants of the fundamental equations relating blood CO2 content to plasma content have been reevaluated. An iterative computer technique was used to empirically derive appropriate constants from data obtained from nine healthy male subjects at rest and at several exercise work loads. A calculation was derived that fitted the data well [difference 0.02 +/- 1.19 ml/100 (SD) ml, r = 0.98] blood CCO2 = plasma CCO2 (Formula: see text) where plasma CCO2 = 2.226.s.plasma PCO2.(1 + 10pH-pK'), CCO2 is CO2 content, SO2 is O2 saturation, s is the plasma CO2 solubility coefficient, and pK' is the apparent pK [s and pK' are from the equations of Kelman (Respir. Physiol. 3: 111-115, 1967)].

Effect of verapamil on polycythaemia secondary to hypoxia in rats.

1. Polycythaemia occurs in man secondary to chronic hypoxaemia, and may lead to morbidity from hyperviscosity of the blood. Hypoxaemic rats develop similar changes. We have investigated the effect of the calcium antagonist verapamil upon the polycythaemic response to hypoxia in rats. 2. Control groups of 10 male rats breathed air in an environmental chamber for 28 days. Hypoxic groups breathed a normobaric atmosphere of 10% oxygen for 6 h each day, and air for the remaining 18 h. Control and hypoxic groups were treated with intraperitoneal or subcutaneous water, or with intraperitoneal or subcutaneous water plus verapamil. 3. On day 28, packed cell volume (PCV) was measured by a microhaematocrit technique and red cell mass (RCM) by dilution of injected 51Cr-labelled rat erythrocytes. 4. PCV and RCM were significantly higher in all the hypoxic groups compared with the control groups (P less than 0.01 in each case). 5. PCV and RCM were significantly lower in the hypoxic groups treated with intraperitoneal or subcutaneous verapamil than in the hypoxic groups treated with intraperitoneal or subcutaneous water (P less than 0.01). There were no significant differences between PCV and RCM in verapamil- and water-treated normoxic control groups. Verapamil had no effect on the shift of the oxygen/haemoglobin dissociation curve produced by hypoxia. 6. Verapamil reduces the polycythaemic response to repeated intermittent hypoxia in rats. Venesection is usually performed for excessive secondary polycythaemia in man. Our results suggest a possible therapeutic role for verapamil in such individuals.

The receptor-binding and membrane-fusion properties of influenza virus variants selected using anti-haemagglutinin monoclonal antibodies.

A monoclonal antibody raised against X-31 influenza virus reacted with the majority of natural H3N2 viruses isolated between 1968 and 1982. A number of variants of X-31 and of a receptor-binding mutant of X-31 were selected by the antibody during virus replication in eggs and MDCK cells. Antibody-binding assays indicated that the viruses selected were not antigenic variants and analyses using derivatized erythrocytes showed that their receptor-binding properties differed from those of the parent viruses. The amino acid substitutions in the variants were all located in the vicinity of the receptor-binding site and the structural consequences are discussed in relation to the three-dimensional structure of X-31 HA. In addition all of the variants fused membranes at higher pH than wild-type virus indicating that structural modifications in the distal globular region of HA influence the low pH-induced conformational change required for membrane fusion.

Antigenic and amino acid sequence analysis of the variants of H1N1 influenza virus in 1986.

Since their reintroduction to human populations in 1977, influenza A viruses of the H1N1 subtype have undergone antigenic drift. Recently a distinct antigenic variant, A/Singapore/6/86, has been almost exclusively isolated internationally, and the antigenic properties and amino acid sequence of its haemagglutinin have been determined and compared with those of the haemagglutinins of other H1N1 viruses, in particular A/Chile/1/83. Fourteen amino acid sequence differences are detected between the HA1 components of these two viruses, ten of which are different from equivalent residues in the haemagglutinins of all H1N1 viruses isolated between 1982 and 1983, and seven of which are novel in the haemagglutinins of all H1N1 viruses sequenced to date. The results are discussed in relation to the three-dimensional structure of the haemagglutinin and the location of the previously defined antigenically important regions.