In vitro differentiation of c-myb(-/-) ES cells reveals that the colony forming capacity of unilineage macrophage precursors and myeloid progenitor commitment are c-Myb independent

Mice homozygous for an inactivated c-myb allele exhibit embryonic (primitive) blood formation but die at about day 15 of gestation because of a failure to generate adult (definitive) haemopoiesis. Recently, it has been shown that commitment to definitive haemopoiesis does occur in vivo, but that some point in the subsequent development towards the differentiated lineages is compromised. Here we have asked whether it is possible to demonstrate this same distinction between the development of primitive and definitive haemopoiesis during the in vitro differentiation of c-myb null ES cells, and whether this can be used to define more precisely at which developmental stage the absence of c-Myb blocks the adult haemopoietic lineages. We investigated the kinetics of progenitor formation and commitment to differentiation using a combination of colony forming assays and analysis of RNA and surface antigen expression. Primitive unilineage macrophage and erythroid precursor commitment could develop in the absence of c-Myb. No precursors characteristic of definitive haemopoiesis were detected; nevertheless, we could show the expression of a programme of transcription and surface antigens which is consistent with the appearance of definitive progenitors blocked at an early multipotential stage.

Comparative genome sequence analysis of the Bpa/Str region in mouse and Man

The progress of human and mouse genome sequencing programs presages the possibility of systematic cross-species comparison of the two genomes as a powerful tool for gene and regulatory element identification. As the opportunities to perform comparative sequence analysis emerge, it is important to develop parameters for such analyses and to examine the outcomes of cross-species comparison. Our analysis used gene prediction and a database search of 430 kb of genomic sequence covering the Bpa/Str region of the mouse X chromosome, and 745 kb of genomic sequence from the homologous human X chromosome region. We identified 11 genes in mouse and 13 genes and two pseudogenes in human. In addition, we compared the mouse and human sequences using pairwise alignment and searches for evolutionary conserved regions (ECRs) exceeding a defined threshold of sequence identity. This approach aided the identification of at least four further putative conserved genes in the region. Comparative sequencing revealed that this region is a mosaic in evolutionary terms, with considerably more rearrangement between the two species than realized previously from comparative mapping studies. Surprisingly, this region showed an extremely high LINE and low SINE content, low G+C content, and yet a relatively high gene density, in contrast to the low gene density usually associated with such regions.

beta-Adrenergic regulation of proinflammatory cytokines in humans

OBJECTIVES

To investigate the effects of beta-adrenergic stimulation on IL-6 secretion in humans, and to determine the potential contribution to this response of adipocytes and peripheral blood cells (PBC).

DESIGN

Experimental study in 8 human volunteers, and in vitro studies on murine adipocyte cell-line, 3T3.L1 and 3T3.F442A, and human PBC.

MEASUREMENTS

Plasma IL-6 and TNFalpha responses to isoprenaline infusion. Cytokine secretion from differentiated adipocyte cell-lines and PBC in response to isoprenaline.

RESULTS

Plasma IL-6 levels increased ninefold (median) by 180 min (baseline median 0.51 [interquartile range 0.47-1.4] vs 180 mins 4.53 [2.58-5.69] pg ml(-1), P=0.01). One hour after infusion, IL-6 levels (2.9 [1.27-3.98]) were lower than at 180 min (P=0.05), but higher than baseline (P=0.01). TNFalpha levels were unchanged. Differentiated adipocytes incubated in isoprenaline (0-0.1 microM) released significantly increased amounts of IL-6 whereas no response was elicited from PBC.

CONCLUSIONS

The induction of IL-6 observed in vivo may be attributed to the beta-adrenergic stimulation of IL-6 release specifically from adipocytes, as opposed to circulating blood cells.

Late-life depression as a possible predictor of dementia: cross-sectional and short-term follow-up results

The authors explored cognitive functioning of a group of elderly subjects with depression. The group as a whole, and, in particular, the late-onset group (LOD), demonstrated cognitive impairment on the Mattis Dementia Rating Scale (MDRS). Subgroup differences were significant at P=0.004. This between-group difference was not seen when age and level of education were controlled. In the LOD group, 47.5% (vs. 31.5% of the early-onset group [P=0.025]), scored below the cutoff for dementia. Age-at-onset status in a logistic regression model predicted MDRS category, and treatment of the depression had little effect on cognition. Results support the hypothesis that late-life depression, particularly LOD, is associated with cognitive impairment that may represent early AD.

The role of depression severity in the cognitive functioning of elderly subjects with central nervous system disease

OBJECTIVE

To examine the hypothesis that there is a causal relation between depression and cognitive dysfunction in patients with central nervous system (CNS) disease.

DESIGN

Retrospective analysis of a clinical database.

SETTING

Tertiary geriatric day hospital.

PATIENTS

Sixty-five patients with depression and CNS disease, and 201 patients with depression but without CNS disease.

OUTCOME MEASURES

Scores on the Hamilton Depression Rating Scale (Ham-D) and the Mattis Dementia Rating Scale (MDRS).

RESULTS

A logistic regression analysis using MDRS status as the dependent variable, and a number of clinical variables as the predictor variables, showed that, in patients with CNS disease, only the Ham-D score predicted MDRS status (R = -0.19, p = 0.02). Ham-D score even more strongly predicted scores on a frontal system subtest of the MDRS (R = -0.262, p = 0.005). Ham-D score did not predict MDRS status in patients without CNS disease. Mean Mini Mental State Examination scores for the group with CNS disease were 25.1 at admission and 26.1 at discharge (p < 0.001).

CONCLUSIONS

These findings suggest that depression contributes to frontal cognitive dysfunction in patients with CNS disease.

Work-based learning as a means of developing and assessing nursing competence

Work-Based Learning is the bringing together of self-knowledge, expertise at work and formal knowledge. It takes a structured and learner-managed approach to maximizing opportunities for learning and professional development in the workplace. The development and assessment of nursing competence can be facilitated through Work-Based Learning, although this may require pedagogic and structural changes within nurse education. There are a number of conditions which must accompany effective participative learning, and these are discussed in the paper in relation to examples of nursing programmes. This method of learning and assessment has potential to bridge the gap between theory and practice, and as such it can only be achieved through commitment and partnership between the individual practitioner, clinical services and universities.

Lessons from the other side: what can we learn from the private sector?

Business has reacted in an impressive manner to increasing globalisation, short-term stock market pressure for performance, emerging industries and new technologies. While the private sector has become increasingly competitive, the public sector has not adopted this commercial rigour. Funding pressures on health services will continue, as will increasing consumer and staff demands and the blurring of public and private health care provision. As a result, there are lessons and techniques the public and private health sectors should learn from each other. I have drawn the issues that follow from my experience in the steel and food industries.

Depression in holocaust survivors: profile and treatment outcome in a geriatric day hospital program

The profile of depressive symptoms and the outcome of treatment in Holocaust Survivors (HS) versus non-Holocaust Survivors (NS), attending a Psychiatric Day Hospital Program for depression, were evaluated retrospectively using a clinical database. Approximately 24% of the study population were Holocaust Survivors (HS). The HS group was more likely to receive a diagnosis of major depressive disorder or episode as one of their diagnoses. The HS group, in particular those survivors who had been in ghettos or in concentration camps, were more likely to be given a diagnosis of post-traumatic stress disorder. Both groups showed improvement from baseline in their ratings of depression on the Hamilton Depression Rating Scale (HDRS) and Geriatric Depression Scale at the time of discharge (p<0.001). However, there were no significant differences between the groups in terms of their ratings of depression either at admission, at discharge or in their degree of improvement. Likewise, there was no significant difference between the groups in the profile of their depression, as per the sub-scales of the HDRS, with the exception that the HS group displayed more 'insight' than the NS group (p=0.002). The NS group scored higher on the Mattis Dementia Rating Scale compared to the HS group (119.1 versus 125.4, p<0.001), even when level of education was covaried; however, language may be an important confound. In conclusion, there was no significant difference in the profile or outcome of depression between groups. However, the HS group was more likely to receive a diagnosis of post-traumatic stress disorder, displayed more 'insight', and appear to differ in their cognitive profile.

Subcutaneous administration of recombinant glycosylated interleukin 6 in patients with cancer: pharmacokinetics, pharmacodynamics and immunomodulatory effects

This is the first report of the serum profile of a glycosylated recombinant form of human IL-6 (rhIL-6) administered subcutaneously (1-10 microg/kg/day) in a phase I/II trial as a thrombopoietic agent in patients with advanced cancer. The pharmacodynamic effects of IL-6 were also examined. Detailed pharmacokinetic measurements were made in four patients. Peak concentrations at 5-8 h and a median t0.5 of ca. 5 h were similar to those previously reported for non-glycosylated IL-6. However, higher peak concentrations and apparent differences in effective dose levels to those previously reported with the non-glycosylated form were seen. Indications of an apparent attenuation in circulating IL-6 concentrations with continuing injections were seen in eight of 10 patients examined but anti-IL-6 antibody generation was seen in only two patients. Soluble interleukin 6 receptor concentrations generally decreased. No major changes in T cell subsets were seen but expression of CD25 and CD54 by T lymphocytes significantly increased, accompanied by marked increases in soluble CD25 (sIL-2R) and CD54 (sICAM-1). No consistent change in B cells, monocytes or NK cells were seen. No evidence for induction of TNF-alpha was found. This study demonstrates similar biological effects of glycosylated rhIL-6 to those reported for the non-glycosylated form but illustrates several apparent differences which are discussed further.

Herpesvirus saimiri-based gene delivery vectors maintain heterologous expression throughout mouse embryonic stem cell differentiation in vitro

In order to achieve a high efficiency of gene delivery into rare cell types like stem cells the use of viral vectors is presently without alternative. An ideal stem cell gene therapy vector would be able to infect primitive progenitor cells and sustain or activate gene expression in differentiated progeny. However, many viral vectors are inactivated when introduced in developing systems where cell differentiation occurs. To this end, we have developed a mouse in vitro model for testing herpesvirus saimiri (HVS)-based gene therapy vectors. We demonstrate here for the first time that HVS is able to infect totipotent mouse embryonic stem (ES) cells with high efficiency. We have transduced ES cells with a recombinant virus carrying the enhanced green fluorescent protein (EGFP) gene and the neomycin resistance gene (NeoR) driven by a CMV promoter and the SV40 promoter, respectively. ES cells maintain the viral episomal genome and can be terminally differentiated into mature haematopoietic cells. Moreover, heterologous gene expression is maintained throughout in vitro differentiation. Besides its obvious use in gene therapy, this unique expression system has wide ranging applications in studies aimed at understanding gene function and expression in cell differentiation and development.

Are there gender differences in patients presenting with unstable angina?

BACKGROUND

There are limited studies on gender differences in patients with unstable angina. We investigated the influence of gender in these patients in a tertiary referral centre.

METHODS AND RESULTS

Three hundred and thirteen consecutive patients (210 men and 103 women) with unstable angina were studied over a 42-month period. Patient characteristics, cardiovascular risk factors and subsequent management including coronary artery bypass graft (CABG) operation and percutaneous transluminal coronary angioplasty (PTCA) were investigated. There was no difference in age [61.6 (11.0) (S.D.) years for men vs. 63.5 (10.5) years for women]. Diabetes mellitus and hypertension were more common in women (diabetes, 11% vs. 23%, P = 0.007; hypertension, 32% vs. 52%; P = 0.001). The number of smokers was greater in men (73% vs. 46%, P = 0.00001). There was no difference in the prevalence of hypercholesterolaemia or in the incidence of previous myocardial infarction, previous history of angina and family history of ischaemic heart disease. The duration of unstable angina before presentation to the referring hospital was similar in both sexes. The use of aspirin, intravenous heparin and antianginal drugs was also comparable in the two genders. The number of coronary arteries involved in men and women appeared similar (one vessel, 22% vs. 27%; two vessels, 26% vs. 21%; three vessels, 52% vs. 52% in men and women, respectively). The proportion of men and women who underwent subsequent revascularisation was also similar (CABG, 31% vs. 33%; PTCA, 42% vs. 40%). The overall in-hospital mortality was higher in women (6.8% vs. 2.8%), but was not statistically significant (P = 0.18).

CONCLUSIONS

Gender differences in unstable angina manifest in the preponderance of selected risk factors including diabetes mellitus and hypertension in women and smoking in men. There is no difference in age, the degree of coronary artery involvement and the subsequent management in a tertiary referral centre.

FreeStyle: a small-volume electrochemical glucose sensor for home blood glucose testing

FreeStyle accurately measures the concentration of glucose in a 300-nL volume of capillary blood obtained with significantly reduced pain from the forearm where the density of capillaries is much lower than in the fingertips. The readings are independent of temperature, of altitude (O2 pressure) and of hematocrit in the 0%-60% range. At their physiological levels, none of the often interfering constituents of blood affect the readings.

Effects of hyperbaric oxygen on ventricular performance, pulmonary blood volume, and systemic and pulmonary vascular resistance

The cardiovascular effects of hyperbaric (3 atm abs) air, 100% oxygen, and hyperbaric oxygen (HBO2) at 3 atm abs were investigated in 13 pentobarbital-anesthetized dogs. We measured heart rate, arterial pressure, pulmonary artery pressure, right atrial pressure, left and right ventricular pressure, and cardiac output. From these we determined end diastolic pressure, +/-maximal dp/dt, maximal (dp/p), end systolic elastance, cardiac work, and systemic (SVR) and pulmonary vascular resistance (PVR). Pulmonary blood volume was obtained from the mean transit time of ascorbic acid. The significant results with HBO2 were a decrease in heart rate, cardiac output, and cardiac work. All left ventricular performance indices decreased, without a change in preload or afterload. In contrast, only right ventricular -dp/dt decreased. SVR increased but PVR did not change; 100% O2 produced similar but less pronounced responses. Hyperbaric air had only mild effects. Pulmonary blood volume and lung wet/dry ratio did not change. Our data suggest that HBO2 may act by a differential effect on the autonomic innervation of the right and left ventricles. The resultant ventricular imbalance may be of clinical importance in the mechanism of pulmonary edema in patients in congestive heart failure undergoing hyperbaric therapy.

Evidence for triacylglycerol synthesis in the lumen of microsomes via a lipolysis-esterification pathway involving carnitine acyltransferases

In this study a pathway for the synthesis of triacylglycerol (TAG) within the lumen of the endoplasmic reticulum has been identified, using microsomes that had been preconditioned by depleting their endogenous substrates and then fusing them with biotinylated phosphatidylserine liposomes containing CoASH and Mg(2+). Incubating these fused microsomes with tri[(3)H] oleoylglycerol and [(14)C]oleoyl-CoA yielded microsome-associated triacylglycerol, which resisted extensive washing and had a [(3)H]:[(14)C] ratio close to 2:1. The data suggest that the precursor tri[(3)H]oleoylglycerol was hydrolyzed by microsomal lipase to membrane-bound di[(3)H]oleoylglycerol and subsequently re-esterified with luminal [(14)C]oleoyl-CoA. The accumulation of TAG within the microsomes, even when overt diacylglycerol acyltransferase (DGAT I) was inactive, is consistent with the existence of a latent diacylglycerol acyltransferase (DGAT II) within the microsomal lumen. Moreover, because luminal synthesis of TAG was carnitine-dependent and markedly reduced by glybenclamide, a potent carnitine acyltransferase inhibitor, microsomal carnitine acyltransferase appears to be essential for trafficking the [(14)C]oleoyl-CoA into the microsomal lumen for subsequent incorporation into newly synthesized TAG. This study thus provides the first direct demonstration of an enzymatic process leading to the synthesis of luminal triacylglycerol, which is a major component of very low density lipoproteins.

Stent implantation reduces restenosis in patients with suboptimal results following coronary angioplasty

BACKGROUND

Primary intracoronary stenting reduces the rate of restenosis when compared with balloon angioplasty (PTCA) in selected patients. The strategy of PTCA followed by provisional stent placement for suboptimal PTCA results may be preferable to universal stenting but has not yet been tested in a randomized trial.

METHODS

An attempt was made to obtain an optimal result with PTCA alone in 143 patients. Stenting was required in 50 patients (35%) for significant coronary dissection or PTCA failure. In the remaining 93 patients, the angiographic result was assessed immediately using on-line quantitative coronary angiography and classified as either optimal (<15% residual stenosis) or suboptimal (>/=15% residual stenosis). Sixteen patients (11%) had an optimal result from PTCA. The remaining 77 (54%) patients had a suboptimal result and were immediately randomized either to no further treatment or to the placement of a stent. The primary end-point was the rate of restenosis (>50% stenosis), assessed by quantitative coronary angiography, at 6 months.

RESULTS

Angiographic follow-up was completed in 132 patients. Restenosis occurred in 53 (36,69)% of patients with a suboptimal result randomized to PTCA alone compared with 24 (12,41)% of patients randomized to stent (P=0.023). There was no significant difference in minimal luminal diameter at follow-up between the randomized groups. The rate of restenosis was 14 (2,43)% in patients with an optimal PTCA result and 14 (5,28)% in those that required stenting.

CONCLUSIONS

Optimal angiographic results following conventional PTCA are rare and the restenosis rate following suboptimal results is high. The strategy of stenting suboptimal results is associated with a significant reduction in the rate of stenosis.

Reading numbers aloud: a measure of the limiting effect of breathlessness in patients with cancer

BACKGROUND

Progress in the treatment of breathlessness at rest or on minimum exertion in patients with cancer requires a practical and valid method of measuring symptoms. A study was undertaken to explore the practicality, repeatability, and sensitivity of reading numbers as a form of exercise test in this group of patients.

METHODS

Thirty patients with cancer and 30 age matched healthy subjects read numbers aloud as quickly and clearly as they could for 60 seconds. After five readings the maximum number of numbers read and the number read per breath was noted. This procedure was carried out twice in one day and one week later to assess within and between day repeatability. The sensitivity of the test was assessed by making measurements in 13 patients with cancer before and after drainage of their pleural effusion.

RESULTS

The concept was easily understood by all subjects. Twelve patients were unable to complete five readings in all tests due to tiredness. Compared with control subjects patients read fewer numbers in the three tests (87-89% of control) and fewer numbers per breath (59-60% of control). Repeatability was good both within and between days. After drainage of their effusion all patients were less breathless and there was an increase in both the maximum number of numbers read (23%) and the number read per breath (60%).

CONCLUSIONS

The number of numbers read and the number read per breath over 60 seconds was practical, easy to carry out, showed good repeatability within and between days and was sensitive to the improvement seen following drainage of a pleural effusion. It may be a useful measure of the limiting effect of breathlessness in this group of patients.

How well do we monitor patient satisfaction? Problems with the nation-wide patient survey

AIM

To outline and assess the accuracy and usefulness of the quarterly nation-wide patient survey of all New Zealand hospitals.

METHOD

Data generated by an improved patient survey at South Auckland Health (SAH) was used to examine some of the problems and issues pertaining to this survey: i.e. the format of the questionnaire; unintended consequences of the specific methodology employed and the usefulness of the obtained information.

RESULTS

Evidence is provided to show that the inpatient sample is not representative of the SAH patient population and that patients across different socio-demographic groups have different satisfaction rates. Additional research projects undertaken by the authors at SAH suggest that different methods of completing the questionnaire can significantly influence the results.

CONCLUSION

The nation-wide patient survey is in need of revision, if it is to be used as an effective management tool within hospitals and for the sector as a whole.

The SynerGraft valve: a new acellular (nonglutaraldehyde-fixed) tissue heart valve for autologous recellularization first experimental studies before clinical implantation

The durability of current bioprosthetic heart valves is diminished by glutaraldehyde-associated leaflet calcification or by the associated absence of a cellular component capable of repair of wear-related damage. As a novel tissue engineering approach to improving replacement heart valve durability, we have developed a decellularization process to replace the use of cross-linking to limit xenograft antigenicity. The effectiveness of this process was assessed in a weanling sheep right ventricular outflow tract reconstruction model where valve function, calcification, and recellularization were examined. Porcine aortic valves were decellularized by a process designed to remove all histologically demonstrable leaflet cells. Stentless, bioprosthetic valves were fabricated from acellular tissues, cryopreserved, sterilized, and then implanted as pulmonary valve replacements in 4- to 6-month old female Suffolk sheep. Sheep aortic valves were implanted as allograft control subjects. After 150 days, the grafts were explanted and assessed histologically and by atomic absorption spectrophotometry for calcium content. All valves were hemodynamically functional at explant. Histological examination showed intact leaflets with in-growth of host fibroblastoid cells in all explanted porcine valves and no evidence of calcification. Porcine leaflet calcium content was unchanged over the duration of the implant (1.0+/-1.2 vs 1.5+/-1.8 mg/g dry weight, P = ns). Decellularization can stabilize xenogenic heart valves. Lack of calcification of acellular aortic leaflets suggests that prolonged durability of such valves is attainable without the use of cross-linking agents. The repopulation of the leaflet matrix offers additional promise of durability based on revitalization of the graft in vivo.

System memory in violent incidents: evidence from patterns of reoccurrence

For 20% of a sample of 1,078 violent incidents reported in British bars and pubs, another incident was reported at the same premises within 6 months. Log-survival analysis revealed nonrandom sequences that demonstrate a system memory effect separate from any biases involving particular venues. The rate of reoccurrence was not constant during the 6 months following incidents but was significantly higher for Weeks 1-4, approximated to the mean value for Weeks 5-12, and declined for Weeks 13-26. Reoccurrence was particularly likely in the first 3-4 days after an incident. Risk of reoccurrence was further increased for incidents that involved either threats or the exit and return of the assailants within that original incident. Results support the view that "violence breeds violence" and demonstrate the need for increased staff vigilance for up to 12 weeks following a violent incident, and particularly during the first few days and weeks.

Appendix: education and information resources in hyperbaric medicine

A comprehensive listing of hyperbaric medicine resources is provided. These resources serve the educational and information needs of those who wish to enter this medical specialty, as well as those who practice it. A selected hyperbaric specific bibliography is included, as is the methodology to stay current with the scientific and technological advances of this field.

The management of epilepsy in a hospital for people with a learning disability

The study examined changes in the use of antiepileptic drugs (AEDs) in a large hospital for people with a learning disability over a 2 year period, the use of investigations, and the presence of medication side-effects. The surveys were carried out in 1993 and 1995/6. In 1993, 27% of patients were being treated for epilepsy and in 1995/6, 30.1%. Ninety percent and 82.4% of patients, respectively, were receiving one or two AEDs. In the second survey there were fewer prescriptions for phenobarbitone (5.8% vs. 12.5%) and an increase in the use of lamotrigine (21.6% vs. 5%), gabapentin (5.8% vs. 0) and vigabatrin (3.9% vs. 2.5% in 1993). Side-effects were recorded in 6 (11.8%) patients. Seven (21.2%) patients receiving carbamazepine were found to have hyponatraemia. Of the 54 electroencephalograms (EEGs) requested, 41 (76%) were reported as abnormal. Six CT brain scans had been conducted, of which five were abnormal. People receiving antipsychotic drugs had fewer seizures than average.