Atherothrombosis and plaque heterology: different location or a unique disease?

Formation of unstable plaques frequently results in atherothrombosis, the major cause for ischaemic stroke, myocardial infarction and peripheral arterial disease. Patients who have symptomatic thrombosis in one vascular bed are at increased risk of disease in other beds. However, the development of the disease in carotid, coronary and peripheral arteries may have different pathophysiology suggesting that more complex treatment protocols may have to be designed to reduce plaque development at different locations. In this review we describe the known risk factors, compare the developmental features of coronary and carotid plaque development and determine their association with end-point ischaemic events. Differences are also seen in the genetic contribution to plaque development as well as in the deregulation of gene and protein expression and cellular signal transduction activity of active cells in regions susceptible to thrombosis. Differences between carotid and coronary artery plaque development might help to explain the differences in anatomopathological appearance and risk of rupture.

Leukaemia inhibitory factor is over-expressed by ischaemic brain tissue concomitant with reduced plasma expression following acute stroke

Leukaemia inhibitory factor (LIF) is a glycoprotein of the interleukin-6 family, which has potent pro-inflammatory properties and is involved in regulation of neuronal differentiation. We have previously identified its upregulation in gene microarrays following acute ischaemic stroke in man. LIF expression and localization was measured in human ischaemic stroke autopsy specimens, in a rat model of middle cerebral artery occlusion (MCAO) and in human foetal neural cell cultures following oxygen-glucose deprivation (OGD) by Western blotting and immunohistochemistry. Circulating LIF was determined in the plasma of patients in the hyper-acute stroke phase using a multiplex enzyme-linked-immunosorbent serologic assay system. Patients demonstrated an increase in LIF expression in peri-infarcted regions with localization in neurons and endothelial cells of microvessels surrounding the infarcted core. The rat MCAO model showed similar upregulation in neurons with a peak increase at 90 min. Circulating serum LIF expression was significantly decreased in the hyper-acute phase of stroke. Brain-derived neurons and glia cultured in vitro demonstrated an increase in gene/protein and protein expression respectively following exposure to OGD. Increased LIF expression in peri-infarcted regions and sequestration from the peripheral circulation in acute stroke patients are characteristic of the pathobiological response to ischaemia and tissue damage.

Pathophysiology of Acute Ischaemic Stroke: An Analysis of Common Signalling Mechanisms and Identification of New Molecular Targets

Stroke continues to be a major cause of death and disability. The currently available therapies have proven to be highly unsatisfactory (except thrombolysis) and attempts are being made to identify and characterize signalling proteins which could be exploited to design novel therapeutic modalities. The pathophysiology of stroke is a complex process. Delaying interventions from the first hours to days or even weeks following blood vessel occlusion may lead to worsening or impairment of recovery in later stages. The objective of this review is to critically evaluate the major mechanisms underlying stroke pathophysiology, especially the role of cell signalling in excitotoxicity, inflammation, apoptosis, neuroprotection and angiogenesis, and highlight potential novel targets for drug discovery.

Gastro-oesophageal reflux treatment for prolonged non-specific cough in children and adults

BACKGROUND

Cough is a very common symptom presenting to medical practitioners. Gastroesophageal reflux disease (GORD) is said to be the causative factor in up to 41% of adults with chronic cough. However cough and GORD are common ailments and their co-existence by chance is high. Also cough can induce reflux episodes. Treatment for GORD includes conservative measures (diet manipulation), pharmaceutical therapy (motility or prokinetic agents, H(2) antagonist and proton pump inhibitors (PPI)) and fundoplication.

OBJECTIVES

To evaluate the efficacy of GORD treatment on chronic cough in children and adults with GORD and prolonged cough that is not related to an underlying respiratory disease i.e. non-specific chronic cough.

SEARCH STRATEGY

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register Collaboration and Cochrane Airways Group, MEDLINE and EMBASE databases, review articles and reference lists of relevant articles were searched. The date of last search was 7th April 2006.

SELECTION CRITERIA

All randomised controlled trials on GORD treatment for cough in children and adults without primary lung disease.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Two independent reviewers selected, extracted and assessed data for inclusion. Authors were contacted for further information. Data was analysed as "intention to treat" as well as "treatment received". Paediatric and adults data were considered separately. Sensitivity analyses were performed.

MAIN RESULTS

Thirteen studies (3 paediatric, 10 adults) were included. Data from six were available for analysis. None of the paediatric studies could be included in meta-analysis. In adults, analysis on use of H(2) antagonist, motility agents and conservative treatment for GORD were not possible (from lack of data) and there were no controlled studies on fundoplication as an intervention. Six adult studies comparing PPI (2-3 months) to placebo were analysed for various outcomes in the meta-analysis. Enrolment of subjects for two studies were primarily from medical clinics and another 4 studies were otolaryngology clinic patients or patients with laryngitis. Using "intention to treat", pooled data from 4 studies resulted in no significant difference between treatment and placebo in total resolution of cough, Odds Ratio 0.46 (95% CI 0.19 to 1.15). Pooled data revealed no overall significant improvement in cough outcomes (end of trial or change in cough scores). Significant differences were only found in sensitivity analyses. A significant improvement in change of cough scores was found in end of intervention (2-3 months) in those receiving PPI with a standardised mean difference of -0.41 (95%CI -0.75, -0.07) using GIV analysis on cross over trials. Two studies reported improvement in cough after 5 days to 2 weeks of treatment.

AUTHORS' CONCLUSIONS

There is insufficient evidence to definitely conclude that GORD treatment with PPI is universally beneficial for cough associated with GORD in adults. The beneficial effect was only seen in sub-analysis and its effect was small. The optimal duration of such a trial of therapy to evaluate response could not be ascertained in the meta-analysis although two RCTs reported significant change by 2 weeks of therapy. Clinicians should be cognisant of a period (natural resolution with time) and placebo effect in studies that utilise cough as an outcome measure. Data in children are inconclusive. Future paediatric and adult studies are needed whereby studies should be double blind, randomised controlled, parallel design, using treatments for at least two months, with validated subjective and objective cough outcomes and include ascertainment of time to respond as well as assessment of acid and/or non acid reflux whilst on therapy.

HIV, sexually transmitted infections, and risk behaviours in male sex workers in London over a 10 year period

OBJECTIVES

To describe changing characteristics of men who sold sex in London between 1994 and 2003.

METHODS

A baseline survey of 823 male sex workers attending a specialist clinic, plus follow up of 628 men for 1379 person years.

RESULTS

Men recruited earlier (1994 to 1996) were more likely than those recruited later (2000 to 2003) to be UK born and to self define as homosexual. Later recruits included more men from South/Central America and eastern Europe and a higher proportion reported regular female partners. Baseline prevalence of HIV was 9% (59/636), and multivariate analysis showed an associated with injecting drug use and unprotected sex with a casual partner. During follow up there were 49 incident cases of HIV. Survival analysis showed earlier recruitment (1994-6) to be associated with a higher incidence of HIV. The prevalence of gonorrhoea increased over time.

CONCLUSIONS

Men who sell sex are at risk of HIV and other STIs, but these risks do not appear to be directly linked to sex work. The changing demographics of these men is associated with different patterns of infection and poses challenges for service delivery.

Hepatitis B vaccination for male sex workers: the experience of a specialist GUM service

BACKGROUND

Male sex workers are at risk of blood borne viruses but may have limited access to sexual health services, including vaccination. We explore factors associated with hepatitis B vaccination uptake among male sex workers in London

METHODS

Follow up study of men attending the Working Men's Project, a specialist health project for men who sell sex, between 1994 and 2003.

RESULTS

At baseline 797 men were screened for hepatitis B; 308 were not eligible for vaccination because of past or current infection (155, 19.4%) or previous vaccination 153 (19.2%). Of the 489 men eligible for a full course of vaccination 292 (59.8%) completed the course. Completion rates fell over time: men recruited up to 1999 were more likely to complete the course than those recruited more recently (177/259, 68.3% compared with 115/229, 50.2%, OR 2.14, 95% CI 1.48 to 3.09).

CONCLUSION

This specialist service achieved a high rate of vaccine completion in the early years, but the decline is a concern. It may reflect wider availability of vaccination elsewhere and a more mobile population of sex workers. Shorter courses may achieve a higher completion.

Gene activation and protein expression following ischaemic stroke: strategies towards neuroprotection

Current understanding of the patho-physiological events that follow acute ischaemic stroke suggests that treatment regimens could be improved by manipulation of gene transcription and protein activation, especially in the penumbra region adjacent to the infarct. An immediate reduction in excitotoxicity in response to hypoxia, as well as the subsequent inflammatory response, and beneficial control of reperfusion via collateral revascularization near the ischaemic border, together with greater control over apoptotic cell death, could improve neuronal survival and ultimately patient recovery. Highly significant differences in gene activation between animal models for stroke by middle cerebral artery occlusion, and stroke in patients, may explain why current treatment strategies based on animal models of stroke often fail. We have highlighted the complexities of cellular regulation and demonstrated a requirement for detailed studies examining cell specific protective mechanisms after stroke in humans.

Gastro-oesophageal reflux treatment for prolonged non-specific cough in children and adults

BACKGROUND

Cough is a very common symptom presenting to medical practitioners. Gastroesophageal reflux disease (GORD) is said to be the causative factor in up to 41% of adults with chronic cough. However cough and GORD are common ailments and their co-existence by chance is high. Also cough can induce reflux episodes. Treatment for GORD includes conservative measures (diet manipulation), pharmaceutical therapy (motility or prokinetic agents, H(2) antagonist and proton pump inhibitors (PPI)) and fundoplication.

OBJECTIVES

To evaluate the efficacy of GORD treatment on chronic cough in children and adults with GORD and prolonged cough that is not related to an underlying respiratory disease i.e. non-specific chronic cough.

SEARCH STRATEGY

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register Collaboration and Cochrane Airways Group, MEDLINE and EMBASE databases, review articles and reference lists of relevant articles were searched. The date of last search was 4th April 2004.

SELECTION CRITERIA

All randomised controlled trials on GORD treatment for cough in children and adults without primary lung disease.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Two independent reviewers selected, extracted and assessed data for inclusion. Authors were contacted for further information. Data was analysed as "intention to treat" as well as "treatment received". Paediatric and adults data were considered separately. Sensitivity analyses were performed.

MAIN RESULTS

11 studies (3 paediatric, 8 adults; 383 participants) were included. None of the paediatric studies could be included in meta-analysis. In adults, analysis on use of H(2) antagonist, motility agents and conservative treatment for GORD were not possible (from lack of data) and there were no controlled studies on fundoplication as an intervention. Five adult studies comparing PPI (2-3 months) to placebo were analysed for various outcomes in the meta-analysis. Enrollment of subjects for two studies were primarily from medical clinics and another three studies were otolaryngeal clinic patients. Using "intention to treat", pooled data from three studies resulted in no significant difference between treatment and placebo in total resolution of cough. Pooled data revealed no significant improvement in cough outcomes (end of trial or change in cough scores). Significant differences were only found in sensitivity analysis. A significant improvement in change of cough scores was found in end of intervention (2-3 months) in those receiving PPI with a standardised mean difference of -0.41 (95%CI -0.75, -0.07) using GIV analysis on cross over trials. Two studies reported improvement in cough after 5 days to 2 weeks of treatment. Significant heterogeneity was found between studies using omeprazole and other PPIs.

AUTHORS' CONCLUSIONS

There is insufficient evidence to definitely conclude that GORD treatment with PPI is beneficial for cough associated with GORD in adults. The beneficial effect was only seen in sub-analysis and its effect was small. The optimal duration of such a trial of therapy to evaluate response could not be ascertained in the meta-analysis although two RCTs reported significant change by two weeks of therapy. Clinicians should be cognisant of a period (natural resolution with time) and placebo effect in studies that utilise cough as an outcome measure. Data in children are inconclusive. Future paediatric and adult studies are needed whereby studies should be double blind, randomised controlled, parallel design, using treatments for at least two months, with validated subjective and objective cough outcomes and include ascertainment of time to respond as well as assessment of acid and/or non acid reflux whilst on therapy.

Time-course phosphorylation of the mitogen activated protein (MAP) kinase group of signalling proteins and related molecules following middle cerebral artery occlusion (MCAO) in rats

Recovery from the debilitating effects of ischaemic stroke is variable and unpredictable. To maximize patient recovery, a greater understanding of the molecular mechanisms involved in regulating both apoptosis and the repair processes affecting neuronal protection, particularly in the penumbra region, is desirable. We have previously shown, in human subjects, the increased expression of several growth factors soon after stroke, together with appearance of tyrosine phosphorylated proteins, in particular mitogen activated protein (MAP) kinase (ERK1/2). In this paper, we demonstrate a relatively short-lasting (< 12 h), but substantial increase in expression of phosphorylated proteins, in particular, p-JNK (phosphorylated c-Jun N-terminal kinase) and p-ERK1/2 in both the grey matter penumbra and infarcted tissue of rats, following permanent middle cerebral artery occlusion. p-ERK1/2 was associated with neurones and endothelial cells in the vicinity of the infarct while p-JNK was mainly expressed in neurones. Expression of both p-MEK3/6 and p-p38 MAP kinase was also increased in neurones and astroglia, within 1 h of infarction, p-p38 remaining elevated and associated with neurones and in particular with astroglia in the penumbra region for > 4 days. Evidence suggests that short-term activation of these proteins may be detrimental to neuronal survival, while their transient nature makes them unlikely to support angiogenesis, revascularization and reperfusion over a period of days and weeks. On the other hand, short-medium-term up-regulation of neuronal p-JNK, p-c-Jun, p-Stat-1 and p-p38 might be a factor in the regulation of apoptosis. Therapeutic manipulation of phosphorylation/activation of these and other important signalling intermediates might form the basis of an appropriate treatment to maximize revascularization and neuronal protection after ischaemic stroke.

Effect of glycation on basic fibroblast growth factor induced angiogenesis and activation of associated signal transduction pathways in vascular endothelial cells: possible relevance to wound healing in diabetes

Ineffectual wound healing in hyperglycaemic patients suffering from diabetes mellitus is characterised by a reduction in capillary reformation (angiogenesis). Basic fibroblast growth factor (FGF-2) is secreted by fibroblasts, macrophages and in particular endothelial cells (EC) in response to tissue injury and is important in promotion of neovascularisation. Recently, glycation of FGF-2 has been shown to significantly reduce its activity in vitro. We have examined the kinetics of FGF-2 glycation and compared its ability with that of native FGF-2 to activate mitogenesis, capillary formation and associated signal transduction in bovine aortic EC (BAEC). FGF-2 was exposed to 0.25 M glucose-6-phosphate (G-6-P) for 24-72 h and the degree of glycation determined by matrix assisted laser desorption ionisation mass spectrometry. Native FGF-2 was heterogeneous with Mw in the range 15,153.6-17,903 Da. After 24 h incubation with G-6-P there was evidence of glycation, and the mass increase corresponded to addition of 2.7 mol of G-6-P residues; after 48 h, 4 mol sugar was added and this increased to 8.7 after 72 h. Dimerisation of FGF-2 was observed after 72 h of treatment. Induction of mitogenesis in BAEC was significantly reduced by 25%-40% after treatment for 48-96 h with glycated (24 h) FGF-2 (gFGF-2; 100 pg/ml-5 ng/ml; P < 0.05), whilst capillary tubule formation was significantly reduced by between 60% and 90% (100 pg/ml-1 ng/ml; P < 0.05) after 5 days compared to native FGF-2. Subsequent investigation of the signal transduction molecules associated with mitogenesis showed a reduction in FGF-2 induced tyrosine phosphorylated proteins of approximate Mw 20-150 kDa between 10 min and 24 h, in particular, mitogen activated protein kinase (MAPK)/early response kinase (ERK-1, ERK-2), after glycation. To determine the reason for reduced angiogenic activity of gFGF-2, we compared its binding characteristics to that of native FGF-2. Total binding of gFGF-2 to the cell surface was significantly reduced in BAEC analysed by FACS compared to native FGF-2 (P < 0.05). Further investigation using 125I-labelled differentially washed samples, demonstrated a significant reduction in gFGF-2 binding to the high affinity tyrosine kinase receptor (46%) compared to native FGF-2. In summary, glycation of FGF-2 in vitro occurs rapidly within 24 h in the presence of elevated levels of G-6-P. Glycation caused a significant reduction in the ability of FGF-2 to bind to the tyrosine kinase receptor and activate signal transduction pathways responsible for both mitogenesis and capillary formation in BAEC. These results could help to explain the mechanism behind impaired wound healing in patients with diabetes mellitus.

DNA topoisomerase I and II expression in drug resistant germ cell tumours

A small number of testicular germ cell tumours are refractory to current chemotherapy regimens. DNA topoisomerase I is the target for several new drugs and a potential candidate treatment for chemorefractory germ cell tumours. DNA topoisomerase II alpha is the target for etoposide, which is currently used regularly in germ cell tumour treatment. The expression of DNA topoisomerase I and II alpha were therefore assessed immunohistochemically in a range of testicular tumours, especially those with persistent malignant elements on retroperitoneal lymph node dissection. Pre-chemotherapy orchidectomy specimens were matched with post-chemotherapy retroperitoneal lymph node dissections to examine changes in expression. There was considerable variation in the expression of topoisomerase I in different tumour types. Both yolk sac tumours and teratoma, mature showed universal expression of topoisomerase I, while 38% of seminomas and 30% of embryonal carcinomas were positive. Strong topoisomerase II alpha expression was found in embryonal carcinoma. There was a negative correlation between topoisomerase I and II alpha expression (P=0.004) and downregulation of topoisomerase II alpha after chemotherapy (P=0.02). Topoisomerase I expression appears to increase in those cases with residual teratoma, mature, but is largely unchanged in those cases remaining as embryonal carcinoma. These results suggest that topoisomerase I inhibitors may be useful in chemorefractory germ cell tumours, especially yolk sac tumours and where there are unresectable residual teratoma, mature deposits.

STI prevention and the male sex industry in London: evaluating a pilot peer education programme

OBJECTIVE

To evaluate the effectiveness of a pilot peer education STI prevention programme with male sex workers.

DESIGN

A process and outcome evaluation of the pilot programme undertaken in three London male escort agencies, using a quasi-experimental design.

SUBJECTS

Workers in three London escort agencies, including 88 who completed a questionnaire, five peer educators, and a further 16 men (including management) working in two of these agencies.

METHODS

A peer education STI prevention programme run by the Working Men Project (WMP), a specialist sexual health service for male sex workers, was piloted in two London escort agencies. Five male sex workers participated in a 2 day peer education training programme. They then returned to their respective agencies to disseminate information and condoms, in an attempt to influence norms of behaviour. An outcome evaluation aimed to assess changes in STI related knowledge, high risk sexual behaviour, and attendance at a sexual health service. A pre-intervention questionnaire assessing variables such as STI related knowledge, sexual behaviour, and demographic information was administered in both agency A and agency B and a third agency, C, which acted as a control. Ten weeks after the peer educators returned to their agencies, the same questionnaire was administered in the same agencies. Peer educator referrals to the WMP were also recorded over this time period. The process evaluation involved interviews and focus groups with peer educators, and the completion of diaries about their experiences in the role. A further 16 men working in the agencies (including managers and an owner) were interviewed about their experience of the programme. Participant observation was also undertaken through regular outreach work to the agencies.

RESULTS

57 men completed the questionnaire at time 1 and 44 at time 2. Unfortunately, only 13 of these were matched, precluding any meaningful analysis of change in STI related knowledge and sexual behaviour. The questionnaire provided a profile of the men working in the agencies. Of the 88 men who completed the questionnaire at least once, the majority were homosexual, and in their late teens/early 20s. Most were of a "white" ethnic group, though there was some range within these categories. Most preferred to speak English and education levels were high. Relative STI knowledge revealed a high understanding of HIV and hepatitis B, moderate understanding of gonorrhoea, syphilis, genital warts and herpes, and little knowledge of non-specific urethritis (NSU) or chlamydia. Sexual behaviour suggested a highly sexually active population with both male and female paying and non-paying partners. Condom use was highest for paying partners, particularly for anal sex. Condom use for oral sex with all partners was less consistent, and condom use for all types of sex with regular partners was lower than with other partners. The small number of men engaging in vaginal sex with paying and regular partners were less likely to use condoms. 26 new patients registered at the WMP as a result of peer educator referrals, representing 65% of all new contacts over the study period. The process evaluation revealed that while the training programme was considered adequate and while peer educators felt the programme and their roles to be a success, their experience of the role was difficult. The role of management support was crucial in supporting the programme. The assumption that "peers" are particularly effective educators was not borne out by the results. While peers were considered suitable to discuss some aspects of the industry, many preferred to consult "professionals" about health related matters. The concept of "peers" was problematic with most of the men drawing "peers" from subgroups within the agencies. Other constraints on behaviour such as a lack of power, particularly with regard to a lack of management support, or poverty, had a substantial impact on behaviour which were not influenced by the peer educators.

CONCLUSIONS

The study illustrated the difficulties of utilising quasi-experimental evaluation methodology with this client group. It also demonstrated the limitations of peer education based on information provision health education models which focus on individual behaviour change. Suggestions are given for future interventions.

Activation of MAP kinase (ERK-1/ERK-2), tyrosine kinase and VEGF in the human brain following acute ischaemic stroke

We examined expression of vascular endothelial growth factor (VEGF), phosphorylation of mitogen activated protein kinase (MAP) kinase (ERK1 and ERK2) and tyrosine phosphorylation in 19 patients (aged 58-90 years; mean 75) who died 1-44 days after acute ischaemic stroke. In the grey matter penumbra, 13 of 19 patients showed an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 8-fold, ERK2; 2.2- to 11-fold) compared with normal contralateral tissue. In almost all cases, ERK-2 phosphorylation was higher than ERK1. Of these 13 patients, 11 also showed a general increase in tyrosine kinase phosphorylation, and eight expressed increased levels of VEGF protein (2.5- to 5-fold). In tissue examined directly from the infarct core, activation of the above proteins was not observed in the, majority of patients. In the white matter, seven of 19 patients (penumbra), and nine of 19 patients (stroke) had an increase in MAP kinase tyrosine phosphorylation (ERK1; 2.0- to 4.6-fold and ERK-2; 2.3- to 5.4-fold respectively) compared with normal contralateral tissue. There was no relationship between activation of MAP kinase and expression of VEGF. Examination of phosphorylated MAP kinase by immunohistochemistry revealed an increase in immunoreactivity in neurones, astroglial cells, reactive microglia and endothelial cells in areas surrounding infarcts, especially in areas with the highest density of microvessels. In conclusion, chronic activation of tyrosine phosphorylated events, in particular redistribution and phosphorylation of MAP kinase (ERK1/ERK2) occurs consistently in the grey matter penumbra of brain tissue following ischaemic stroke, and may be associated with increase in expression of VEGF. These signal transduction events could be important determinants of the extent of neuronal survival and/or angiogenic activity in the recovering brain tissue.

Serial measurement of vascular endothelial growth factor and transforming growth factor-beta1 in serum of patients with acute ischemic stroke

BACKGROUND AND PURPOSE

Both vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1) are expressed in higher than normal concentrations in the penumbra of patients after ischemic stroke. Because both cytokines are central to the processes of angiogenesis, tissue inflammation, and fibrosis, we performed serial measurements of these cytokines in patients with cerebral infarction and determined their relationship to stroke etiology and volume.

METHODS

We serially (at days 0, 1, 3, 7, and 14) measured the serum levels of VEGF and active TGF-beta1 in 29 patients with acute ischemic stroke. Age-matched healthy subjects (n=26) were used as controls.

RESULTS

Expression of VEGF was significantly increased in the majority of patients after acute stroke at each of the time points compared with normal controls. Highest expression occurred at day 7 (588+/-121 pg/mL; P=0.005), and it remained significantly elevated at 14 days after stroke. Expression of VEGF correlated with infarct volume, clinical disability (Scandinavian Stroke Scale), and peripheral leukocytosis and was significantly higher in patients with atherothrombotic large-vessel disease and ischemic heart disease (P<0.05 in all cases). In contrast, expression of active TGF-beta1 was not significantly different from control patients at any of the measured time points. When the mean concentration of TGF-beta1 from each patient (pooled time points) was compared with the control mean, a significant increase was found in only 2 patients, whereas levels decreased in 12 patients (P<0.05). There was no correlation between circulating active TGF-beta1 and VEGF expression, leukocytosis, stroke subtype, or patient disability as assessed by Scandinavian Stroke Scale score.

CONCLUSIONS

VEGF but not TGF-beta1 showed a dramatic increase in serum of stroke patients. Correlation between stroke severity and VEGF concentration suggests it could be involved in the subsequent repair processes resulting in partial recovery after stroke. Correlation between VEGF expression and peripheral leukocytosis suggests that these changes may also reflect the immunologic status of the patient. VEGF may play an important role in the pathophysiology of acute ischemic stroke and could be of value in future treatment strategies.

Physiological concentrations of gangliosides GM1, GM2 and GM3 differentially modify basic-fibroblast-growth-factor-induced mitogenesis and the associated signalling pathway in endothelial cells

It has been suggested that gangliosides can influence the growth of cells by modulation of growth-factor-receptor signalling. The activation of endothelial cells (EC) during angiogenesis is crucial for tumour growth and for metastasis, also for numerous other physiological and pathological situations. Pre-treatment of bovine aortic endothelial cells (BAEC) with GM1 or GM2 (5-20 microM) inhibited basic-fibroblast-growth-factor (bFGF)-induced mitogenesis, but GM3 (0.1-20 microM) acted synergistically, increasing proliferation above that of bFGF alone (p < 0.05). The mitogenic effect of all 3 gangliosides was markedly reduced if the cells were washed to remove excess gangliosides from the medium before addition of bFGF. We further show that GM1 and to a lesser extent GM2 modify bFGF binding to its receptor and inhibit the associated mitogenic signal-transduction pathway of protein-tyrosine phosphorylation of 40 to 120 kDa, PLCgamma1, MAP kinase and protein-kinase-C activation. In contrast, GM3 increased tyrosine phosphorylation and MAP kinase activity, as compared with bFGF alone. The observed differential modulation of bFGF-induced mitogenesis by GM1, GM2 and GM3 was at concentrations routinely occurring in the serum of cancer patients. The results suggest that circulating gangliosides may have a role in regulating solid-tumour growth by modulating angiogenesis.

Angiogenic oligosaccharides of hyaluronan induce protein tyrosine kinase activity in endothelial cells and activate a cytoplasmic signal transduction pathway resulting in proliferation

We have recently shown that the degradation products of hyaluronan of 3 to 10 disaccharides (o-HA), but not native high molecular weight hyaluronan, can induce angiogenesis in vivo and, as such, o-HA is an important regulator of the neovascularization process. As a continuation of this work, we have studied the cytoplasmic signal transduction pathways responsible for o-HA-activated endothelial cell proliferation. We show that the addition of o-HA (1 microg/ml) to bovine aortic endothelial cells induces tyrosine phosphorylation of multiple proteins within 1 minute and that the activity remains above basal levels for at least 24 hours. Increased phosphorylation of the CD44 receptor was also observed. Pretreatment of cells with an anti-CD44-receptor antibody (5 microg/ml) or the tyrosine kinase inhibitor genistein (10 microM) inhibited both o-HA-induced proliferation (p < 0.05) and protein tyrosine phosphorylation. In comparison, native hyaluronan had little effect on tyrosine phosphorylation across the same time period. Protein kinase C (PKC) activity was increased 2- to 3-fold in the membranes of cells treated with o-HA, and a pretreatment with phorbol 12,13-dibutyrate (PDBu) to down-regulate PKC significantly inhibited o-HA-induced cell proliferation (p < 0.05). Examination by Western blotting showed that only the betaI and epsilon isoforms remained translocated to the membrane for at least 24 hours. These isoforms seem to be involved in modulating the proliferative effects of o-HA, because the transient translocation of PKC isoforms by PDBu was not sufficient to induce mitogenesis. Furthermore, we show that PKC activation of the cytoplasmic kinase cascade (Raf-1 kinase, MAP kinase kinase [MEK-1], and extracellular signal-regulated kinase [ERK-1]) by o-HA culminated in the nuclear translocation of ERK-1. This pathway is essentially linear, as shown by the ability of specific enzyme inhibitors (PDBu and PD98059) to prevent both activation of ERK-1- and o-HA-induced proliferation. We conclude that phosphorylation of the CD44 receptor results in an increase in tyrosine phosphorylation, leading to the activation of a cytoplasmic cascade and cell proliferation; this concurs with previous work, which showed that o-HA-induced proliferation of endothelial cells is CD44-receptor-mediated and accompanied by early response gene activation.

Protein kinase C expression and activity in the human brain after ischaemic stroke

We examined the expression of protein kinase C isoforms in infarcted tissue, penumbra and contralateral brain tissue from 10 patients who died between 1-52 days after ischaemic stroke. Ten patients aged 61-89 years were used in the study. Tissue samples were assayed for protein kinase C activity using a non-radioactive method, and specific isoforms expression determined by Western blotting and staining with anti-PKC polyclonal antibodies. There was a 2-24 fold increase in PKC gamma in the ischaemic penumbra of nine out of 10 patients compared to contralateral tissue. In infarcted tissue expression of PKC gamma was not significantly changed in any of 10 samples but the beta I isoform increased in eight and the beta II in nine patients. There was no significant change in expression in PKC alpha or in infarct or penumbra. Differences in total PKC activity were not specific in seven out of eight patients and it is difficult to estimate their significance. In conclusion after ischaemia there was an altered expression of PKC isoforms with an increase of PKC gamma in the surviving penumbra and beta I and beta II in the infarcted core.

The ganglioside profile of human bladder cell lines and the effect of exogenous gangliosides on their growth

The ganglioside composition of three human bladder cell lines, two tumourigenic (RT112 and EJ138) and one non-tumourigenic (Hu609) were analysed by thin-layer chromatography and mass spectroscopy. Sub-confluent cultures of the three cell lines expressed mainly monosialogangliosides. Xenografts of EJ138 cells expressed nearly twice as much GM(3) as tissue cultured cells. Proliferation of Hu609 and EJ138 cells measured by H-3-thymidine incorporation was increased by GM(3) and further enhanced by addition of EGF. Paradoxically the migration of all three cell lines was inhibited by a mixture of monosialogangliosides and the inhibition was abolished by EGF.

Cricothyrotomy performed by prehospital personnel: a comparison of two techniques in a human cadaver model

Little is known about the proficiency of prehospital personnel when performing cricothyrotomies. The authors compared two techniques for establishing an airway through the cricothyroid membrane used by paramedic students. One technique used a prepackaged kit that consisted of a dilator that is passed percutaneously through a breakaway needle. This percutaneous device (PD) was compared with a standard surgical approach (SA) using a scalpel and endotracheal tube. Data was collected on a total of 44 paramedic students who were allowed to attempt each of the procedures. No significant difference in the success rate on the first attempt was found between the two procedures (86% for the SA and 73% for the PD; P = .186). The surgical approach was significantly faster (46 +/- 17 seconds v 103 +/- 62 seconds; P < .01). It was also judged to be significantly easier to perform when evaluated on a linear analog scale (SA, 2.6 +/- 2.0 v PD, 5.1 +/- 2.8; P < .001). Because some procedures were performed on cadavers whose cricothyroid membranes had already been violated, the procedures performed on intact membranes only were also analyzed. Similar, statistically significant differences for insertion time and ease of insertion were again found. Prehospital personnel can be trained to perform cricothyrotomies with a reasonable degree of proficiency. A traditional surgical approach, however, may be faster and less difficult to perform than a comparable procedure using a commercially available percutaneous device.

Effect of pharmacological purging on natural killer cell number and activity in human bone marrow

We assayed natural killer (NK) cell activity and phenotype from human bone marrow (BM) following "purge" with 4-hydroperoxycyclophosphamide (4HC) at 60 micrograms/ml for 30 min in vitro. In all cases studied, lytic activity against the K562 cell line was either significantly decreased or abolished following 4HC purge. Although NK activity was significantly affected by 4HC treatment, no major differences in the phenotype between the purged and unpurged population were seen. Further, while in vitro culture of BM with IL2 resulted in a significant increment of NK activity, no IL-2 responsive cells were found in the 4HC purged BM after 14 days of culture. This study demonstrates that pharmacological purging of bone marrow results in a persistent functional decline of NK cell activity and may serve as a useful model for the study of the ontogeny of NK cells.