Healthful new oil from macadamia nuts

Fatty acid profiles were obtained for macadamia nut oil and several other cooking oils. Macadamia nut oil contained the highest level (79%) of monounsaturated fatty acids. Macadamia nut oil is low (4%) in the omega-6 fatty acid 18:2n-6 and saturated fatty acids. Fatty acid profiles for popcorn cooked in several oils were obtained for comparison because of public awareness and concern over high levels of saturated fat found in popcorn sold in theaters. The nutritional implications of using macadamia nut oil are discussed.

ACE for whom? Implications for clinical practice of post-infarct trials

OBJECTIVE

To determine how many lives would be saved if patients were routinely treated with ACE inhibitors after myocardial infarction according to the criteria of four recent major clinical trials, and to estimate the costs and benefits of these approaches.

DESIGN

Retrospective survey.

SETTING

The Nottingham Health District.

PATIENTS

Data from 7855 patients admitted between 1989 and 1990 were combined and the selection criteria of four major clinical trials (AIRE, SAVE, GISSI-3, and ISIS-4) were applied.

RESULTS

Of the patients admitted in Nottingham with confirmed myocardial infarcts 39% were eligible for AIRE and 8% for SAVE. In patients with suspected myocardial infarction as defined by the major trials, 60% would have been eligible for GISSI-3 and 63% for ISIS-4. Treating appropriate patients in accordance with these trials would have saved 20 (AIRE), 3 (SAVE), 4 (GISSI-3) and 5 (ISIS-4) lives each year in Nottingham at a drug cost of 5400 pounds, 33 pounds 791, 2730 pounds, and 4116 pounds per life per year saved respectively.

CONCLUSIONS

Short-term treatment with ACE inhibition appears to be cheaper but such an approach would save fewer lives. The AIRE study is the most applicable to current clinical practice but ACE inhibitors should be offered routinely to patients satisfying the criteria of any of the four major clinical trials.

Aboriginal wellbeing and liquor licensing legislation in Western Australia

This paper is based on the results of a project undertaken as the basis for a submission to the committee established to review the Western Australian Liquor Licensing Act 1988. It reports on key issues relating to liquor licensing, as identified by members of regional Aboriginal organisations. Among these issues are the promotion of alcohol consumption and misuse, discriminatory practices by licensees and the police and the need for greater community involvement in liquor licensing decisions. To address these issues, members of the participating organisations proposed: inclusion of a harm-minimisation objective in the Act, education and training programs for the public, licensees and the police, and industry funding for harm-minimisation programs.

Intestinal T cells in CD8 alpha knockout mice and T cell receptor transgenic mice

Intraepithelial lymphocytes (IEL) refer to the T cells located at the epithelium of the intestines. Unlike the T cells in other peripheral lymphoid organs, the majority of IEL express the CD8 cell surface protein. To study the role of CD8 in the ontogeny and the function of IEL, phenotypic analysis of IEL from CD8 alpha knockout mice and normal mice was performed. The CD8 alpha gene in CD8 alpha knockout mice was disrupted by homologous recombination. These mice are defective in thymic maturation of cytotoxic T cells. In normal mice, alpha beta T cells that were CD8 alpha alpha+ or CD4+ CD8 alpha alpha+, and gamma delta T cells that were CD8 alpha alpha+, were the distinct populations found only in IEL. In CD8 alpha knockout mice, the population size of IEL remained normal, but the majority of IEL were CD4- CD8- T cells expressing alpha beta or gamma delta T cell receptors. IEL from the H-Y transgenic mice2, which express the male H-Y antigen specific T cell receptor in a normal and in a CD8 alpha-null background, were also studied. In contrast to thymic derived T cells, CD8 alpha alpha+ IEL with the autoreactive transgenic T cell receptor were not deleted, but clonally expanded in the male transgenic mice. Interestingly, no pathological symptoms were observed in the intestines of these mice. In the absence of CD8 alpha expression, the H-Y specific autoreactive IEL did not accumulate in the intestines. The results suggest that CD8 alpha alpha+ IEL are derived extra-thymically and their responses towards antigens require the CD8 accessory molecule.

Neuroimaging of meningeal disease

In the past two decades, the advent of CT and MRI has made a considerable impact on the evaluation of meningeal diseases, conditions once regulated to cytological, histopathological, or postmortem analyses alone. This article reviews the imaging findings in various meningeal processes with particular attention to the anatomic definition of the meningeal layers and their relationship to the development of meningeal pathology and consequent imaging characteristics.

Methods of establishing criteria for purchasing coronary angiography in the investigation of chest pain

BACKGROUND

Purchasers may now define how many clinical procedures they wish to buy. In the investigation of chest pain, coronary angiography provides a definitive diagnosis. In clinical practice, the use of coronary angiography varies, so purchasers may choose the sort of service they wish to buy. We reviewed the extent of variation in the investigation of patients in the Trent Region and present a system for establishing criteria for the purchase of coronary angiography.

METHODS

Three studies are presented, based on patients referred to the three referral centres in the Trent Region. First, the appropriateness for investigation, defined as benefit outweighing risk, is determined by expert panel; second, an audit of patients referred for coronary angiography is presented; and third, the likelihood or probability of significant coronary disease is assessed by application of a logistic regression model.

RESULTS

According to the panel criteria, 27 per cent of patients in one centre were judged inappropriate for coronary angiography, 28 per cent in the second centre and 10 per cent in the third. When referred for angiography, extent of anti-anginal medication, symptom severity, use of exercise testing, and result of and planned management after angiography varied widely among centres. The likelihood of significant coronary artery disease could be predicted in 86 per cent of patients.

CONCLUSIONS

Variation in clinical practice does not make the purchasers' task easy. Based upon these studies and clinical trials of coronary artery bypass surgery and coronary angioplasty, we present potential performance indicators which may form the basis of contracts or be used as audit measures.

Kinetics of somatic mutation in lymph node germinal centres

Somatic mutation activity in immunoglobulin V kappa genes during the response to the hapten 2-phenyl-5-oxazolone was measured in lymph node B-cell populations at various timepoints after footpad immunization. When the V kappa Ox1 genes rearranged to the J kappa 5 segment were amplified from genomic DNA using the polymerase chain reaction and sequenced, somatic mutations could be detected as early as day 4 after immunization. Somatic mutations were also detected after sequencing RNA from oxazolone-specific hybridomas derived from lymph node cells at day 4 after immunization. These early mutations were found mostly in cells with a germinal centre phenotype. No indication of selection at the population level by apoptosis was detected until day 7 after immunization. These results suggest somatic mutations can be induced very early during the immune response in lymph node cells, prior to the peak of clonal expansion and selection with regard to antigen binding.

CD40 ligation in B cell activation, isotype switching and memory development

Interaction of CD40 on B cells with its ligand on activated T helper cells is crucial for the generation of mature T-dependent antibody responses. Experimental observations suggest that CD40 ligation acts at several points in B cell differentiation; however, it is not clear whether the consequences of ligation are direct or indirect. While its role in B cell activation is clearly direct we discuss the several ways in which it might drive isotype switching, the influence that it has on the development of memory B cells and the possibility that certain types of T-dependent antibody response are CD40L-independent. Experiments in which the ligation of CD40 is blocked in vivo reveal that early CD40 signals are important for the development of memory B cells but this may only reflect the ability of 'memory precursors' generated by CD40 ligation to accept subsequent programming or survival signals.

Human herpesvirus 6 (HHV-6) is a helper virus for adeno-associated virus type 2 (AAV-2) and the AAV-2 rep gene homologue in HHV-6 can mediate AAV-2 DNA replication and regulate gene expression

We have previously described the apparent acquisition by human herpesvirus 6 (HHV-6) of the multifunctional rep gene of the helper-dependent human parvovirus adeno-associated virus type 2 (AAV-2). We report here that HHV-6 is a full helper virus for AAV-2 replication, suggesting a mechanism for transfer of the rep gene between the two viruses by recombination of replicative intermediates. The HHV-6 rep gene cloned under control of the human cytomegalovirus immediate early promoter complemented replication of a rep-deficient AAV-2 genome. In cotransfection experiments with heterologous promoters linked to the CAT reporter gene, HHV-6 rep activated the human immunodeficiency virus (HIV) long terminal repeat (LTR) in fibroblast cell lines but not in T-cells. In contrast, AAV-2 rep inhibited HIV LTR activity in both fibroblast and T-cell lines. The effect of HHV-6 and AAV-2 rep genes on the HIV LTR was independent of the NF-kappa B, Sp1, and TATA box elements. These results suggest that HHV-6 Rep is a multifunctional regulatory protein with properties related to, but distinct from, those of AAV-2 Rep.

Stabilization of an anthrapyrazole antitumour agent, DuP 937, on complexation with heptakis(2,6-di-O-methyl)-beta-cyclodextrin in aqueous solution

DuP 937, an anthrapyrazole antitumour agent that is chemically unstable in aqueous solution, was shown, by absorption spectroscopy, to form an inclusion complex with heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM beta CD) in aqueous solution. Proton nuclear magnetic resonance spectroscopy was used to determine the stoichiometry and association constant of the complex. The 1:1 stoichiometry of the complex was established by the continuous variation method by following changes in the chemical shifts of aromatic protons of DuP 937. The complex association constants determined by different techniques used in this study were in the same order of magnitude. The kinetics of degradation of DuP 937 in aqueous solution were investigated as a function of DM beta CD concentration at pH 5.5 and 60 degrees C. The results indicated about a seven-fold increase in the stability of DuP 937 in the presence of DM beta CD in aqueous solution.

Do women with acute myocardial infarction receive the same treatment as men?

OBJECTIVE

To determine whether women with acute myocardial infarction in the Nottingham health district receive the same therapeutic interventions as their male counterparts.

DESIGN

Retrospective study.

SETTING

University and City Hospitals, Nottingham.

PATIENTS

All patients admitted with a suspected myocardial infarction during 1989 and 1990.

MAIN OUTCOME MEASURES

Route and timing of admission to hospital, ward of admission, treatment, interventions in hospital, and mortality.

RESULTS

Women with myocardial infarction took longer to arrive in hospital than men. They were less likely to be admitted to the coronary care unit and were therefore also less likely to receive thrombolytic treatment. They seemed to have more severe infarcts, with higher Killip classes, and had a slightly higher mortality during admission. They were less likely than men to receive secondary prophylaxis by being discharged taking beta blockers or aspirin.

CONCLUSIONS

Survival chances both in hospital and after discharge in women with acute myocardial infarction are reduced because they do not have the same opportunity for therapeutic intervention as men.

Adequacy of lymphadenectomy in laparoscopic-assisted colectomy for colorectal cancer: a preliminary report

The hypothesis that the length of bowel and amount of mesentery resected with laparoscopically assisted colectomy are comparable to traditional open techniques was tested by means of a chart review of prospectively collected data of 22 laparoscopically assisted colectomies, 35 open colectomies performed by the same surgeon, and 39 other open colectomies performed at the same institution by other community surgeons. The average length of bowel resected in the laparoscopically assisted group was 21.7 cm, for the traditionally resected group, 31.4 cm, and for the other group, 26.7 cm. No statistically significant differences existed between the three evaluable groups. Although there was a trend toward greater length of bowel resected with the open technique, there was no statistically significant difference in this study. Follow-up at a mean of 24 months after resections shows no abdominal wall recurrences or any unusual patterns of recurrence. It is concluded that laparoscopically assisted colectomy can be performed in select groups to obtain adequate surgical resection for colorectal carcinoma. Further studies to generate larger numbers of patients with longer follow-up to determine the adequacy of resection as well as the comparability of cure rate will be necessary to confirm the findings of this preliminary study.

An eight year experience of conservative management for aortic graft sepsis

This paper describes the results of conservative management of 15 patients with aortic graft infection. The median time to presentation was 4 months. Six of eight grafts that were sent for culture grew organisms, of which the commonest were streptococci and coagulase negative staphylococci. Four patients did not receive intensive antibiotic treatment and all died of sepsis. Eleven patients received intensive intravenous and oral antibiotic therapy and appropriate surgical management; two of these died, one of a stroke and the other of an unknown cause. Two of the nine surviving patients had no surgery and the remainder had procedures to drain pus and unblock occluded grafts, including minimal graft excision in four patients, although two of these subsequently required total graft excision. The follow-up period for six of these nine patients is more than 4 years. For most patients with aortic graft infection aggressive antibiotic treatment supplemented by minimalist surgery is preferable to primary radical surgery.

Prostatitis: a review of diagnosis and management

Prostatitis, the most common urologic disease in men, afflicts between 25% and 50% of all adult men. It is a complex and not well understood condition, partially because of its often obscure pathogenesis. There are four prostatitis diagnostic and treatment categories: 1) acute bacterial prostatitis; 2) chronic bacterial prostatitis; 3) nonbacterial prostatitis; and 4) prostatodynia. This article reviews prostatic anatomy and pathogenesis, as well as diagnostic and treatment categories. This information can assist the primary care practitioner in the identification and management of this common and often puzzling condition.

Memory B cell development but not germinal center formation is impaired by in vivo blockade of CD40-CD40 ligand interaction

To study the role of the CD40-CD40 ligand interaction in the development of memory B cells and its level of action during primary antibody responses in vivo, mice were injected with a soluble CD40 fusion protein (sCD40-gamma 1), so as to block the interaction. The effects of the treatment on the primary antibody response were reminiscent of hyper-immunoglobulin M (IgM) syndrome (HIMG1): antigen-specific IgG responses were grossly inhibited whereas the IgM response was augmented severalfold. The latter observation suggests that there is a T-dependent, CD40 ligand-independent pathway of B cell activation that leads to IgM responses and that a significant component of the IgM in HIMG1 patients is derived from T-dependent responses. The secondary response was not readily blocked by sCD40-gamma 1 treatment, indicating a relative independence of CD40 ligation of antigen-experienced B cells. The most striking finding from these studies is that the development of memory B cell populations (measured by adoptive transfer) is grossly impaired by administration of sCD40-gamma 1 during the early induction phase of the response. It is surprising that although the generation memory is diminished, there is no quantitative difference in the development of germinal centers. Whereas entry of B cells into the memory cell pathway is dependent on CD40 ligation, the clonal expansion of the potential memory precursors in germinal centers seems not to require a CD40 signal.

Regulation of immunological memory

Immunological memory can be regulated during either its development or its maintenance phases. Controversy and confusion surround both methods of regulation, especially in the field of T-cell memory. Recent work has helped in improving our definition of 'a memory cell', but this has been complicated by another major point of contention: whether memory cells are maintained by antigens or other stimuli. Unequivocal advances have recently been made concerning the molecular events involved in memory B cell generation in germinal centers.

Evidence of inadequate investigation and treatment of patients with heart failure

OBJECTIVE

To determine the referral rates to hospital and level of investigation of patients with heart failure, and to assess whether they are receiving optimum management.

DESIGN

A retrospective survey.

SETTING

Nottingham Health District.

PATIENTS

505 patients receiving loop diuretic treatment prescribed by their general practitioner.

MAIN OUTCOME MEASURES

Referral to hospital as an inpatient or outpatient for assessment of assumed cardiac failure; investigations--electrocardiography, chest radiography, and echocardiography; treatment with angiotensin converting enzyme inhibitors.

RESULTS

Only 56% of patients prescribed loop diuretics fulfilled the diagnostic criteria for heart failure. Of these, 74% had been referred to hospital, of whom 80% had had an electrocardiograph, 75% a chest radiograph, but only 31% an echocardiogram. Only 17% of patients with heart failure were being treated with angiotensin converting enzyme inhibitors in conjunction with loop diuretics.

CONCLUSIONS

Patients with heart failure in the Nottingham Health District are not being adequately investigated or receiving the optimum treatment.

Structure and heterogeneity of the a sequences of human herpesvirus 6 strain variants U1102 and Z29 and identification of human telomeric repeat sequences at the genomic termini

The unit-length genome of human herpesvirus 6 (HHV-6) consists of a single unique component (U) bounded by direct repeats DRL and DRR and forms head-to-tail concatemers during productive infection. cis-elements which mediate cleavage and packaging of progeny virions (a sequences) are found at the termini of all herpesvirus genomes. In HHV-6, DRL and DRR are identical and a sequences may therefore also occur at the U-DR junctions to give the arrangement aDRLa-U-aDRRa. We have sequenced the genomic termini, the U-DRR junction, and the DRR.DRL junction of HHV-6 strain variants U1102 and Z29. A (GGGTTA)n motif identical to the human telomeric repeat sequence (TRS) was found adjacent to, but did not form, the termini of both strain variants. The DRL terminus and U-DRR junction contained sequences closely related to that of the well-conserved herpesvirus packaging signal Cn-Gn-Nn-Gn (pac-1), followed by tandem arrays of TRSs separated by single copies of a hexanucleotide repeat. HHV-6 strain U1102 contained repeat sequences not found in HHV-6 Z29. In contrast, the DRR terminus of both variants contained a simple tandem array of TRSs and a close homolog of a herpesvirus pac-2 signal (GCn-Tn-GCn). The DRR.DRL junction was formed by simple head-to-tail linkage of the termini, yielding an intact cleavage signal, pac-2.x.pac-1, where x is the putative cleavage site. The left end of DR was the site of intrastrain size heterogeneity which mapped to the putative a sequences. These findings suggest that TRSs form part of the a sequence of HHV-6 and that the arrangement of a sequences in the genome can be represented as aDRLa-U-a-DRRa.

Variations in the use of coronary angiography in three cities in the Trent Region

OBJECTIVE

To establish the characteristics of patients referred for coronary angiography and the outcome of investigation.

DESIGN

Prospective study.

SETTING

Three regional referral centres at Sheffield, Leicester, and Nottingham.

PATIENTS

All patients referred for investigation from 1 July 1988 to 30 June 1989.

INTERVENTIONS

Coronary angiography for suspected ischaemic heart disease.

MAIN OUTCOME MEASURES

Site and extent of coronary artery disease at coronary angiography and subsequent intervention.

RESULTS

There was a range of clinical activity with a trend towards symptomatic control in Nottingham where patients tended to have more severe angina of long duration and extensive drug treatment. Important coronary lesions were often found and most patients needed coronary artery bypass surgery or angioplasty. In Leicester and Sheffield, where angiography was used prognostically, patients tended to have mild angina of shorter duration and less extensive medical treatment; significant coronary disease was often found but fewer patients were recommended for further intervention.

CONCLUSIONS

Referral for coronary angiography seems to reflect philosophical differences among the referring physicians. Referring patients late in the disease process ensures that most have a subsequent intervention but the benefits of revascularisation may be denied to those with mild symptoms but extensive coronary disease.

Preservation and storage of pancreatic islets

UW solution is currently the best available for short-term cold storage of pancreatic islets for up to 3-5 days, culture for up to 10-14 days, and cryopreservation for longer periods. More research needs to be done to find a better solution, specifically for cold storage of islets. It seems that such a solution is likely to be a derivative of the UW solution.

Implication of prescriptions for nitrates: 7 year follow up of patients treated for angina in general practice

OBJECTIVE

To determine the demand placed on local cardiological services by patients prescribed nitrates for ischaemic heart disease.

DESIGN

A follow up study of a cohort of patients identified in 1985.

SETTING

Nottingham Health District.

PATIENTS

Four hundred and ninety nine patients prescribed nitrates in 1985 for presumed ischaemic heart disease.

MAIN OUTCOME MEASURES

Referral to medical outpatients, admittance to hospital with chest pain, cardiological investigations, and mortality.

RESULTS

Over the seven year period 26% of patients were admitted urgently with chest pain and 15% were referred to the medical outpatient department--a referral rate of 6% a year. 4% of patients had an exercise test and 6% a coronary angiogram. The death rate was 6% a year and a higher proportion died of cardiovascular causes than would be expected in the general population.

CONCLUSIONS

Prescription of nitrate is useful in the determination of the prevalence of ischaemic heart disease. Most patients with angina are still treated within the community, and the rate of specialist investigation remains low.

Follicular dendritic cells help resting B cells to become effective antigen-presenting cells: induction of B7/BB1 and upregulation of major histocompatibility complex class II molecules

This study was designed to investigate whether follicular dendritic cells (FDC) can activate B cells to a state in which they can function as effective antigen-presenting cells (APC). High buoyant density (i.e., resting) B cells specific for 2,4-dinitro-fluorobenzene (DNP) were incubated with DNP-ovalbumin (OVA) bearing FDC, after which their capacity to process and present to an OVA-specific T cell clone was assessed. The efficacies of alternative sources of antigen and activation signals in the induction of B cell APC function were compared with those provided by FDC. Only FDC and Sepharose beads coated with anti-immunoglobulin (Ig)kappa monoclonal antibody provided the necessary stimulus. FDC carrying inappropriate antigens also induced B cell APC function in the presence of exogenous DNP-OVA. However, in circumstances where soluble DNP-OVA was limiting, FDC bearing complexes containing DNP, which could crosslink B cell Ig receptors, induced the most potent APC function. Analysis by flow cytometry revealed that within 24 h of coculture with FDC, a significant percentage of B cells increased in size and expressed higher levels of major histocompatibility complex class II. By 48 h, an upregulation of the costimulatory molecule, B7/BB1, occurred, but only when exposed to the FDC bearing DNP. Taken together, the results demonstrate that FDC have the capacity to activate resting B cells to a state in which they can function as APC for T cells. The stimuli that FDC provide may include: (a) an antigen-dependent signal that influences the upregulation of B7/BB1; and (b) possibly a signal independent of crosslinking mIg that results in Ig internalization. The relevance of these findings to the formation of germinal centers and maintenance of the humoral response is discussed.

Twenty years' experience of myocardial infarction: the value of a heart attack register

Registers of disease serve a multitude of purposes, but are of particular importance to those interested in audit, in monitoring the introduction of new treatment or training programmes, in health service research, and in the planning of hospital services. The Nottingham Heart Attack Register has been in operation since 1973 and is proving to be an important data source. We present a brief history of the Register, describe how to set up a disease register and demonstrate how it can be of value to a wide range of health service staff using examples from our experience.

Analysis of somatic mutation activity in multiple V kappa genes involved in the response to 2-phenyl-5-oxazolone

We have studied somatic mutation activity early in a response to 2-phenyl-5-oxazolone coupled to ovalbumin (phOx-OVA). Although the V kappa Ox1 gene rearranged to J kappa 5 is known to predominate in this response, other closely related V kappa genes are involved. We compared the introduction of point mutations into V kappa Ox1 genes and into a set of related V kappa genes rearranged to the same J kappa segment at two time points after primary immunization. The result showed that quantitation of mutations in a single rearrangement substrate leads to an underestimation of the total mutational activity. There is pronounced somatic mutation activity early within genes that may be absent later in the response. We also show that multiple somatic mutations can be detected in B cells from draining lymph nodes after foot-pad injection with phOx-OVA already at day 7 after immunization. The data suggest a system in which mutation acts early in the response on a wide range of substrates and that selection and expansion of high affinity paratopes occurs later.

Single-cell analysis of Hodgkin and Reed-Sternberg cells: molecular heterogeneity of gene expression and p53 mutations

We have used a single-cell based polymerase chain reaction (PCR) amplification technique to examine the gene expression pattern in single Hodgkin's and Reed-Sternberg (H&RS) cells from seven patients with Hodgkin's disease. Single cells were isolated from lymph nodes obtained at diagnosis (5 of 7 patients) or in first or second relapse (2 of 7 patients). Gene expression was examined by hybridization to a panel of 22 cDNA probes. Forty-nine H&RS cells (and 23 CD3+ or CD20+ lymphocytes as controls) from four patients with nodular sclerosing Hodgkin's disease (HD) and one patient each with lymphocyte predominant and mixed-cellularity HD were successfully analyzed by PCR. This analysis provides evidence that single H&RS cells can coexpress genes characteristic of several hematopoietic lineages (monocytes and lymphocytes). Genes characteristic of activated lymphoid cells are expressed in most H&RS cells. Heterogeneity of expression for certain genes between different cases was found and may eventually define molecular subgroups of HD. These findings indicate that H&RS cells of HD resemble activated hematopoietic cells. Phenotypically similar cells from different cases exhibit characteristic molecular differences. In one patient, 5 of 7 single RS cells showed identical p53 cDNA mutations at codon 246 on specific reverse transcriptase [RT]-PCR and sequencing of exons 5 through 8. The novel experimental approach may provide a valuable tool for understanding the molecular events in newly diagnosed Hodgkin's disease and progression of the disease.

Repair of the anterior mitral leaflet

BACKGROUND

Repair rather than replacement of the diseased mitral valve has been the goal of the cardiac surgeon. Although well accepted for posterior leaflet pathology, a diseased anterior leaflet was believed by some to be irreparable.

AIMS

To assess the result of reconstructive mitral valve surgery involving the anterior mitral leaflet in a selected group of patients.

METHODS

Twenty consecutive patients with degenerative (19), ischaemic (one) and congenital/calcific mitral regurgitation were evaluated. There were five females and 15 males with a mean age of 62 +/- 12 years (41-75 years). The technique used to repair these valves included chordal transposition, leaflet plication commissuroplasty and a new technique we call leaflet repositioning.

RESULT

There were no deaths, follow-up is complete with mean follow-up of 31 +/- five months (two-102) months. All patients have had 2DE and 13 TOE as well. There have been no reoperations due to failure of the repair, 95% of patients are in NYHA Class I-II post operative, while 15% have significant residual regurgitation.

Sensitivity and specificity of the initial working diagnosis in acute myocardial infarction: implications for thrombolysis

Diagnosing acute myocardial infarction promptly allows all eligible patients to be considered for thrombolysis. Objective evidence from the first electrocardiograph may be inadequate and often the doctor must base his immediate management on limited information; an incorrect initial working diagnosis might deny some patients the benefits of thrombolysis or expose others to inappropriate, expensive and potentially harmful treatment. We were interested to find out how accurate our junior doctors were in their assessment of patients admitted with a suspected MI. All patients entered onto the Nottingham Heart Attack Register admitted with suspected acute MI from 1982 to 1986 and 1989 were identified. The initial working diagnosis on admission was obtained from the patient case record. A final diagnosis was assigned according to strictly defined criteria using 'cardiac' enzyme and electrocardiographic results. Sensitivity and specificity of the initial working diagnosis was calculated. Using the initial working diagnosis as a 'screening' test, we found that, while our doctors successfully identified patients with myocardial ischaemia, they were less good at recognizing acute MI--an admission diagnosis of 'MI' carried a sensitivity of 55% and specificity of 88%. This may explain the low utilization of thrombolysis in the Nottingham hospitals. In the first full year since thrombolysis became available, we estimated that we might have exposed 65 patients to the risks of thrombolysis inappropriately and we might have missed treating 244 patients.

Immunological memory

The past five or six years has seen a resurgence of interest in immunological memory. Areas in which important advances have been made of late or in which problems in understanding persist are covered here: (i) Selection of virgin B cells for entry into the peripheral pool. (ii) Expression of immunoglobulin isotypes and other markers on memory B cells. (iii) Development of memory B cells as a separate lineage from primary response B cells. (iv) Sites of production of memory B cells. (v) Signals that rescue mutating B cells in germinal centers, forming the basis of affinity selection, and programming further differentiation. (vi) The myriad markers of memory T cells, in particular CD45R isoforms. (vii) Selective migration pathways of memory T cells and its possible molecular basis. (viii) The lifespan of memory cells and factors that influence their long-term survival. The data accumulated during this period which have vastly increased our understanding of memory have at the same time highlighted unresolved problems that could block further progress in the field. The thorny question that we cannot at present answer is: How does a memory cell differ from an activated cell and, in the case of T cells, from an effector cell? The problem bears on the interpretation of any study that sets out to correlate memory phenotype with memory function. Immunologists may have donned an intellectual straitjacket in their search for the memory cell.

Impact of hospital thrombolysis policy on out-of-hospital response to suspected myocardial infarction

The treatment of acute myocardial infarction changed when several trials reported that thrombolytic agents given within a few hours of infarction improved outcome. We present data from the Nottingham Heart Attack Register comparing 1982-84, when thrombolysis was not available, and 1989-90, when it was hospital policy to give thrombolysis to all patients who arrived within 6 hours of the onset of symptoms, in the absence of a specific contraindication. The number of patients referred with symptoms suggestive of acute myocardial infarction increased by 75% from 1982 to 1990; a diagnosis of "possible infarction" was made in about half of all patients in 1982-84 and 23% in 1989-90. Our current thrombolytic policy has had little impact on patient and general practitioner (GP) behaviour. The GP was contacted by most patients. The median time between the onset of a patient's symptoms and admission to hospital when the GP was involved was 229 min in 1982-84 and 210 min in 1989-90; when he was not involved in arranging the admission median times to admission were 89 min and 75 min, respectively. By 6 hours from symptom onset, 60% of patients had been admitted; by 12 hours, about 70% were in hospital and by 24 hours, 80%. Of 7855 patients admitted with suspected acute myocardial infarction in 1989-90, 4465 were admitted within 6 hours of symptom onset. Of these, 736 (16%) patients received a thrombolytic drug. 389 (9%) patients had a specific, documented contraindication to thrombolysis. Although we estimate that the policy has saved about 8 lives per year, it is not surprising that there has been no improvement in overall case fatality after myocardial infarction.

The appropriateness of the use of cardiovascular procedures. British versus U.S. perspectives

To determine whether patients are less likely to receive an inappropriate procedure in countries that devote fewer resources to health care than does the United States, we studied how appropriately coronary angiography and coronary artery bypass surgery were performed in the Trent region of the United Kingdom. The medical records of 320 patients who underwent coronary angiography and 319 who underwent coronary artery bypass surgery in 1987 and 1988 were randomly selected for review. Despite the United Kingdom's more limited use of coronary angiography and coronary artery bypass surgery, a substantial proportion were still performed for less than appropriate reasons, by both U.S. and U.K. criteria. Merely reducing the rate of use of these procedures will not be sufficient to eliminate such inappropriate use.

CD8 is needed for positive selection but differentially required for negative selection of T cells during thymic ontogeny

During thymic development, immature thymocytes expressing major histocompatibility complex (MHC) class I-restricted T cell receptors (TcR) differentiate into CD8+ T cells with cytolytic functions. To evaluate the role of CD8 in positive and negative selection during thymic ontogeny, mice rendered CD8-null by gene targeting were bred with three lines of transgenic mice expressing unique MHC class I-restricted TcR. In all three instances CD8 was required for positive selection of MHC class I-restricted transgenic T cells. The efficiency of positive selection decreased in accordance with a reduced level of CD8 expression on thymocytes. Surprisingly, there was a differential requirement for CD8 expression in negative selection of MHC class I-restricted thymocytes, depending on the antigen specificity of TcR. These observations show that CD8 is essential for positive selection but is differentially required for negative selection of MHC class I-restricted T cells. Thus thymic selection, at least for negative selection, can occur in the absence of the CD8 accessory molecule.

Demand for hospital services following admission with suspected myocardial infarction in 1983 and 1989

Formulation of business plans by National Health hospitals requires information on likely demands for the services they provide. Two cohorts of patients admitted to the Nottingham hospitals in 1983 and 1989 with suspected myocardial infarction were sampled to determine the workload implications due to initial in-hospital tests, subsequent readmission and outpatient investigations. The results show that attendance in the first year after discharge related principally to cardiac problems, while in subsequent years non-cardiac problems predominated. An estimation of the total workload, based upon 1,000 patients admitted in 1989, suggests that demands for hospital services in the following year include over 4,000 electrocardiographs, 1,400 chest X-rays and 18,000 laboratory tests, and only 118 exercise tests and 37 cardiac catheterisations. Admission with suspected myocardial infarction makes great demand on hospital services in the year after discharge. Any change in practice, which increases the potential demand for cardiac investigations, could have important financial implications for Nottingham hospitals.

CD45RA and CD45RBhigh expression induced by thymic selection events

CD45 is a protein tyrosine phosphatase involved in T and B cell signaling. While peripheral T cells switch CD45 isoforms upon activation, events leading to exon switching during T cell development in the thymus have not been determined. The expression of high molecular weight isoforms of CD45 was examined on thymocytes from nontransgenic and T cell receptor (TCR) transgenic mice. All thymocytes from nontransgenic mice were CD45RB+ as assessed by staining with MB23G2, an anti-CD45RB-specific monoclonal antibody. Interestingly, there was a small population (1-3%) of thymocytes that displayed a higher intensity of staining with MB23G2, CD45RBhigh. CD45RBhigh thymocytes were found in all subsets defined by CD4 and CD8 expression and were also present within the TCR-alpha/beta high population. To analyze whether or not CD45 expression correlated with thymic selection events, expression of CD45RBhigh and a second isoform, CD45RA, was examined on thymocytes from H-Y and 2C TCR transgenic mice and found to correlate with positive and negative selection events but did not occur in nonselecting backgrounds. CD45RA and CD45RBhigh upregulation was also not observed in transgenic mice backcrossed into CD8-deficient mice, a scenario in which there is no positive selection of transgene-expressing thymocytes. These data suggest that modulation of CD45 isoform expression may be involved in thymic selection events.

Activated human T cells express a ligand for the human B cell-associated antigen CD40 which participates in T cell-dependent activation of B lymphocytes

To identify the ligand for the B cell-associated antigen CD40, we constructed a chimeric immunoglobulin molecule where the extracellular portion of the CD40 protein replaced the normal immunoglobulin variable region. No binding was detected on resting peripheral blood T cells. However, following T cell activation with phorbol esters and ionomycin, the chimeric protein bound specifically to activated human T cells and precipitated a 35-kDa protein from such cells. The induction of the CD40 ligand was detectable on the cell surface after 1 h, with maximal expression after 8 h of stimulation. The T cells expressing CD40 ligand were predominantly CD4 positive, although a proportion of CD8-positive cells also expressed the protein. There was no particular correlation with CD45 phenotype. Finally, we found that soluble CD40 inhibited T-dependent B cell proliferation. The results are discussed in the context of cognate interactions between B and T cells.

Immunohistochemical localization of basic fibroblast growth factor within the mouse uterus

Uterine samples were either rapidly frozen in liquid nitrogen or placed in Bouin's fixative. A commercial primary polyclonal antibody made in rabbits against human recombinant basic fibroblast growth factor (bFGF) was used. Western blot analysis indicated that the antibody was specific for bFGF and did not react with acidic FGF. The primary antibody was followed by either goat anti-rabbit immunoglobulin G (IgG) conjugated to the fluorescent phycobiliprotein tracer phycoerythrin or biotinylated goat anti-rabbit IgG and a biotin-avidin-peroxidase complex. Specificity controls using adjacent sections were carried out by (i) substituting normal rabbit sera for the primary antisera, (ii) omitting the primary antisera or (iii) extracting sections with NaCl (2 mol l-1) prior to the immunochemical procedures. No binding of the antibody was observed with any of the specificity control sections. The connective tissue stroma and the basal lamina associated with uterine glandular and surface epithelial layers were positive for bFGF. Localization was not observed within surface or glandular epithelial cells. The basal lamina and endothelial cells associated with blood vessels within the uterus and the smooth muscle cells of the myometrium were positive for bFGF. There were no differences in uterine localization patterns or intensity during the oestrous cycle or after ovariectomy and steroid hormone supplementation. These studies demonstrate the specific localization of bFGF within the mouse uterus.

Netwhat?

The hallmark of an antibody response is considered to be its specificity for the immunogen. Nonetheless, most antibody elicited by an immunogen has been reported to be unreactive with it. We have evaluated specificity by characterizing the primary antibody response of mice to heat-aggregated human gamma-globulin with four approaches: (a) quantification of antibody-producing cells; (b) hybridoma analysis; (c) in situ antigen binding and (d) analysis of secreted antibody. The results show that the nonspecific component of this response is negligible. These observations suggest that such a component is not a basic feature of the antibody response and it is discussed that nonantigen-specific antibody may arise from a variety of causes many of which are artifactual.

Myocardial infarction in patients over 75 1982-1990

Admissions to hospital of patients aged 75 or over with symptoms suggestive of acute myocardial infarction have increased markedly since 1982. Patients over 75 present to hospital as soon after the onset of symptoms as do younger patients; they require more treatment with diuretics and digoxin than do younger patients and their fatality rate is higher. Despite this, the chance of patients over 75, especially women, being admitted to a Coronary Care Unit, and so being treated with a thrombolytic and being monitored closely for the complications of acute infarction are much less than those for patients under 75. If we are confident that we can influence the outcome of and reduce fatality from acute myocardial infarction, we should be prepared to offer elderly patients the same opportunities for treatment that we currently afford to younger patients.

Less mortality but more relapses in experimental allergic encephalomyelitis in CD8-/- mice

Mice lacking in CD8 were generated from homologous recombination in embryonal stem cells at the CD8 locus and bred with the experimental allergic encephalomyelitis (EAE)-susceptible PL/JH-2u through four backcross generations to investigate the role of CD8+ T cells in this model of multiple sclerosis. The disease onset and susceptibility were similar to those of wild-type mice. However, the mutant mice had a milder acute EAE, reflected by fewer deaths, but more chronic EAE, reflected by a higher frequency of relapse. This suggests that CD8+ T lymphocytes may participate as both effectors and regulators in this animal model.

Follicular dendritic cell-dependent adhesion and proliferation of B cells in vitro

In response to an antigenic challenge, B cells proliferate in germinal centers within secondary lymphoid tissue. Specialized accessory cells, follicular dendritic cells (FDC), and T cells are necessary to drive this reaction. Indirect evidence suggests that FDC provide signals which not only induce B cell proliferation but can rescue B cells programmed to die by apoptosis. An in vitro system was developed to: 1) define the role of FDC and 2) identify molecules involved in this response. Activated, low density B cells and T cells were coisolated with FDC from immune mouse lymph nodes. Upon culturing, large cellular aggregates formed, composed of 1 to 3 FDC interdigitating between 30 to 90 B cells and 1 to 5 T cells. Many of these B cells were undergoing DNA synthesis. Depleting FDC or T cells from the cultures immediately stopped cluster formation and proliferation. Separating clustered vs nonclustered cells revealed that the FDC-associated population remained viable, whereas cells in suspension became apoptotic. The adhesion/activation molecules ICAM-1, LFA-1, and CD44 supported both cluster formation and proliferation. In addition, anti-class II and anti-kappa L chain mAb interfered dramatically with DNA synthesis. This model mimics many of the features of a germinal center and can be used to further study B cell activation, proliferation, and differentiation in vitro.

Follicular dendritic cell-dependent adhesion and proliferation of B cells in vitro

In response to an antigenic challenge, B cells proliferate in germinal centers within secondary lymphoid tissue. Specialized accessory cells, follicular dendritic cells (FDC), and T cells are necessary to drive this reaction. Indirect evidence suggests that FDC provide signals which not only induce B cell proliferation but can rescue B cells programmed to die by apoptosis. An in vitro system was developed to: 1) define the role of FDC and 2) identify molecules involved in this response. Activated, low density B cells and T cells were coisolated with FDC from immune mouse lymph nodes. Upon culturing, large cellular aggregates formed, composed of 1 to 3 FDC interdigitating between 30 to 90 B cells and 1 to 5 T cells. Many of these B cells were undergoing DNA synthesis. Depleting FDC or T cells from the cultures immediately stopped cluster formation and proliferation. Separating clustered vs nonclustered cells revealed that the FDC-associated population remained viable, whereas cells in suspension became apoptotic. The adhesion/activation molecules ICAM-1, LFA-1, and CD44 supported both cluster formation and proliferation. In addition, anti-class II and anti-kappa L chain mAb interfered dramatically with DNA synthesis. This model mimics many of the features of a germinal center and can be used to further study B cell activation, proliferation, and differentiation in vitro.