Prevalence of silent atrial fibrillation in high-risk patients - preliminary results from a European three-country handheld ECG-screening study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Helsefonden Lilly and Herbert Hansens Foundation

Introduction

Patients with atrial fibrillation (AF) should in most cases be offered prophylactic anticoagulation treatment to prevent a stroke. However, the arrhythmia can appear without symptoms, so-called silent AF. Even without symptoms AF constitutes a risk for stroke.

Purpose

To screen high-risk patients with diabetes type 2 (DMII) or heart failure (CHF) for silent AF.

Methods

We included patients > 64 years with either DMII or CHF from out-patient clinics and local health centers. Exclusion criteria were known AF, anticoagulation treatment, recent stroke, or an implanted pacemaker or ICD. Patients were recruited from a total of eleven study centers in three countries. All underwent 14-days of intermittent ECG screening with a handheld ECG recording four times each day; the recordings were digitally stored. AF was diagnosed in cases of irregular heart rhythm and absence of P waves on at least one recording (thirty seconds) or on at least two recordings for a minimum of ten seconds.

Results

In total, 813 patients were included, 541 of these with DMII. The mean age was 73,4 years ± 5,8 SD, 40,7% of the patients were female.

In the DMII group thirteen patients (2.4%) were diagnosed with silent AF and offered anticoagulation. In the CHF group six (2.2%) patients had diagnosed silent AF on the handheld ECG. The prevalence of AF increased with increasing age, see Table 1. Thus, in the youngest group AF was diagnosed in 1.3% of the patients compared to 3.9 % in the age group 75 years or older.

Conclusions

Screening for silent AF in high-risk patients with DMII or CHF seems worthwhile, especially in patients 75 years or older. Abstract Figure. ECG with atrial fibrillation

Unmet informational and supportive care needs of patients with muscle invasive bladder cancer: A systematic review of the evidence

BACKGROUND

Little is known about the unmet supportive care needs of patients affected by muscle invasive bladder cancer (MIBC). We set out to determine the different domains of unmet supportive care needs for patients affected by MIBC.

LITERATURE SEARCH

A systematic review was conducted according to the PRISMA Statement Guidelines. A sensitive search was performed in electronic databases (DARE, Cochrane, MEDLINE, BNI, PsychINFO, EMBASE and CIHAHL) from the earliest date available to January 2017.

DATA EVALUATION

1405 references were retrieved, 8 articles met the eligibility criteria and were appraised and ranked by strength using the levels of evidence.

SYNTHESIS

Individual unmet needs were classified into the following domains: patient-clinician communication, daily living needs, health system/information needs, practical needs, family-related needs, social needs, psychological needs, physical needs and intimacy needs. Patients reported high unmet needs at diagnosis and into survivorship.

CONCLUSIONS

This review contributes to a greater understanding of the unmet supportive care needs of patients affected by MIBC. Findings reflect a paucity of research, but existing studies indicated needs commonly related to intimacy, informational, physical and psychological needs. Despite the emerging evidence-base, the current within study limitations precludes our understanding about how the needs of patients evolve over time.

Genetic Polymorphisms in Organic Cation Transporter 1 Attenuates Hepatic Metformin Exposure in Humans

Metformin has been used successfully to treat type 2 diabetes for decades. However, the efficacy of the drug varies considerably from patient to patient and this may in part be due to its pharmacokinetic properties. The aim of this study was to examine if common polymorphisms in SLC22A1, encoding the transporter protein OCT1, affect the hepatic distribution of metformin in humans. We performed noninvasive ¹¹ C-metformin positron emission tomography (PET)/computed tomography (CT) to determine hepatic exposure in 12 subjects genotyped for variants in SLC22A1. Hepatic distribution of metformin was significantly reduced after oral intake in carriers of M420del and R61C variants in SLC22A1 without being associated with changes in circulating levels of metformin. Our data show that genetic polymorphisms in transporter proteins cause variation in hepatic exposure to metformin, and it demonstrates the application of novel imaging techniques to investigate pharmacogenetic properties in humans.

The Convective Transport of Active Species in the Tropics (CONTRAST) Experiment

The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5° N, 144.8° E) during January-February 2014. Using the NSF/NCAR Gulfstream V research aircraft, the experiment investigated the photochemical environment over the tropical western Pacific (TWP) warm pool, a region of massive deep convection and the major pathway for air to enter the stratosphere during Northern Hemisphere (NH) winter. The new observations provide a wealth of information for quantifying the influence of convection on the vertical distributions of active species. The airborne in situ measurements up to 15 km altitude fill a significant gap by characterizing the abundance and altitude variation of a wide suite of trace gases. These measurements, together with observations of dynamical and microphysical parameters, provide significant new data for constraining and evaluating global chemistry climate models. Measurements include precursor and product gas species of reactive halogen compounds that impact ozone in the upper troposphere/lower stratosphere. High accuracy, in-situ measurements of ozone obtained during CONTRAST quantify ozone concentration profiles in the UT, where previous observations from balloon-borne ozonesondes were often near or below the limit of detection. CONTRAST was one of the three coordinated experiments to observe the TWP during January-February 2014. Together, CONTRAST, ATTREX and CAST, using complementary capabilities of the three aircraft platforms as well as ground-based instrumentation, provide a comprehensive quantification of the regional distribution and vertical structure of natural and pollutant trace gases in the TWP during NH winter, from the oceanic boundary to the lower stratosphere.

Skeletal phenotypes in adult patients with osteogenesis imperfecta-correlations with COL1A1/COL1A2 genotype and collagen structure

Osteogenesis imperfecta (OI) is characterized by a high fracture rate and great heterogeneity. This cross-sectional study presents skeletal investigations and protein analyses in 85 adult OI patients. We find significant differences in bone mass, architecture, and fracture rate that correlate well with the underlying biochemical and molecular abnormalities.

INTRODUCTION

OI is a hereditary disease characterized by compromised connective tissue predominantly caused by mutations in collagen type 1 (COL-1) encoding genes. Widespread symptoms reflect the ubiquity of COL-1 throughout the body. The purpose of this study was to improve our understanding of clinical manifestations by investigating anthropometry and skeletal phenotypes (DXA, HRpQCT) in an adult OI population and compare the findings to underlying COL-1 genotype and structure.

METHODS

The study comprised 85 OI patients aged 45 (19-78) years, Sillence type I (n = 58), III (n = 12), and IV (n = 15). All patients underwent DXA, HRpQCT, spine X-ray, biochemical testing, and anthropometry. COL1A1 and COL1A2 were sequenced and 68 OI causing mutations identified (46 in COL1A1, 22 in COL1A2). Analysis of COL-1 structure (quantitative/qualitative defect) by SDS-PAGE was performed in a subset (n = 67).

RESULTS

A qualitative collagen defect predisposed to a more severe phenotype with reduced aBMD, more fractures, and affected anthropometry compared to patients with a quantitative COL-1 defect (p < 0.05). HRpQCT revealed significant differences between patients with OI type I and IV. Patients with type I had lower vBMD (p < 0.005), thinner cortexes (p < 0.001), and reduced trabecular number (p < 0.005) compared to patients with type IV indicating that HRpQCT may distinguish type I from type IV better than DXA.

CONCLUSION

The defective collagen in patients with OI has pronounced effects on the skeleton. The classical OI types based on the clinical classification show profound differences in bone mass and architecture and the differences correlate well with the underlying biochemical and molecular collagen abnormalities.

Epiphytic bacterial communities of the alga Fucus vesiculosus in oil-contaminated water areas of the Barents Sea

Taxonomic compositions of epiphytic bacterial communities in water areas differing in levels of oil pollution were revealed. In total, 82 bacterial genera belonging to 16 classes and 11 phyla were detected. All detected representatives of epiphytic bacterial communities belonged to the phyla Actinobacteria, Bacteroidetes, Planctomycetes, Proteobacteria, Verrucomicrobia, Acidobacteria, Cyanobacteria, Firmicutes, and Fusobacteria and candidate division TM7. The ratio of the phyla in the communities varied depending on the levels of oil pollution. New data on taxonomic composition of uncultivated epiphytic bacterial communities of Fucus vesiculosus were obtained.

Evaluating sexual function in women after radical cystectomy as treatment for bladder cancer

OBJECTIVE

Sexual function remains a relatively unexplored field within urology, especially for female patients who have undergone radical cystectomy (RC). The aim of this study was to shed light on this area.

MATERIALS AND METHODS

The Female Sexual Function Index (FSFI) questionnaire and other selective questions regarding sexual function were sent to 71 women who had undergone RC and were alive 1 year postsurgery. Forty-one completed questionnaires were returned and analysed using simple descriptive statistical analysis, owing to the small sample size.

RESULTS

The median age of the patients was 67 years (range 39-91 years). Seventy-eight per cent reported being sexually active before surgery and 37% post-surgery. The median FSFI score postsurgery was 4.8 (range 1.2-32). The highest FSFI score was seen in the category of satisfaction, which consists of questions regarding closeness with partner, sexual relationship and overall sex life. Lowest FSFI scores were seen for lubrication, orgasm and pain. Twenty-seven per cent of patients wanted more information on the impact RC would have on their sex lives and many asked for information for their partners.

CONCLUSION

Despite being based on a limited number of patients, this study indicates a need for improvement within this field. Most patients scored below 26 on the FSFI questionnaire, the cut-off for sexual dysfunction. However, many reported being satisfied overall. Thus, the physician's main goal is to identify patients in need of more information and guidance before and after surgery.

A mathematical model approach quantifying patients' response to changes in mechanical ventilation: evaluation in volume support

This paper presents a mathematical model-approach to describe and quantify patient-response to changes in ventilator support. The approach accounts for changes in metabolism (V̇O2, V̇CO2) and serial dead space (VD), and integrates six physiological models of: pulmonary gas-exchange; acid-base chemistry of blood, and cerebrospinal fluid; chemoreflex respiratory-drive; ventilation; and degree of patients' respiratory muscle-response. The approach was evaluated with data from 12 patients on volume support ventilation mode. The models were tuned to baseline measurements of respiratory gases, ventilation, arterial acid-base status, and metabolism. Clinical measurements and model simulated values were compared at five ventilator support levels. The models were shown to adequately describe data in all patients (χ(2), p > 0.2) accounting for changes in V̇CO2, VD and inadequate respiratory muscle-response. F-ratio tests showed that this approach provides a significantly better (p < 0.001) description of measured data than: (a) a similar model omitting the degree of respiratory muscle-response; and (b) a model of constant alveolar ventilation. The approach may help predict patients' response to changes in ventilator support at the bedside.

Next-generation sequencing identifies germline MRE11A variants as markers of radiotherapy outcomes in muscle-invasive bladder cancer

BACKGROUND

Muscle-invasive bladder cancer (MIBC) can be cured by radical radiotherapy (RT). We previously found tumour MRE11 expression to be predictive of survival following RT in MIBC, and this was independently validated in a separate institute. Here, we investigated germline MRE11A variants as possible predictors of RT outcomes in MIBC, using next-generation sequencing (NGS).

PATIENTS AND METHODS

The MRE11A gene was amplified in germline DNA from 186 prospectively recruited MIBC patients treated with RT and sequenced using bar-coded multiplexed NGS. Germline variants were analysed for associations with cancer-specific survival (CSS). For validation as a prognostic or predictive marker, rs1805363 was then genotyped in a cystectomy-treated MIBC cohort of 256 individuals. MRE11A mRNA isoform expression was measured in bladder cancer cell lines and primary tumour samples.

RESULTS

Carriage of at least one of six (five novel) rare variants was associated with the worse RT outcome (hazard ratio [HR] 4.04, 95% confidence interval [95% CI] 1.42-11.51, P = 0.009). The single-nucleotide polymorphism (SNP), rs1805363 (minor allele frequency 11%), was also associated with worse CSS (per-allele HR 2.10, 95% CI 1.34-3.28, Ptrend = 0.001) following RT in MIBC, with a gene-dosage effect observed, but no effect seen on CSS in the cystectomy cohort (Ptrend = 0.89). Furthermore, rs1805363 influenced relative MRE11A isoform expression, with increased isoform 2 expression with carriage of the rs1805363 minor A allele.

CONCLUSIONS

Germline MRE11A SNP rs1805363 was predictive of RT, but not of cystectomy outcome in MIBC. If successfully validated in an independent RT-treated cohort, this SNP could be a useful clinical tool for selecting patients for bladder-conserving treatment.

A functional amino acid substitution in the glucose-dependent insulinotropic polypeptide receptor (GIPR) gene is associated with lower bone mineral density and increased fracture risk

CONTEXT

Food ingestion decreases bone resorption, and glucose-dependent insulinotropic polypeptide (GIP) may mediate this effect. Mice overexpressing GIP have increased osteoblast activity and are rescued from age-related bone loss, whereas GIPR knockout mice have decreased cortical bone mass and compromised bone quality. Carriers of the functional variant GIPR Glu354Gln (rs1800437) have higher plasma glucose 2 hours after glucose ingestion, suggesting that the variant encoding GIPR 354Gln decreases the effect of GIP.

OBJECTIVE

The objective of the study was to investigate the effect of GIPR Glu354Gln on bone mineral density (BMD) and fracture risk.

DESIGN

This was a prospective, comprehensive, cohort study (number NCT00252408).

PARTICIPANTS

A total of 1686 perimenopausal women were included.

MAIN OUTCOME MEASURES

Dual-energy X-ray absorptiometry was performed at baseline and after 10 years. Incident fractures were recorded during the follow-up and were obtained from the Danish National Patient Registry, giving a total follow-up time of a minimum 16 years.

RESULTS

After 10 years, women with the minor frequency C allele of rs1800437 (354Gln) had significantly lower BMD at the femoral neck compared with carriers of the major G-allele (CC: 0.755 ± 0.015 g/cm(2) vs CG: 747 ± 0.005 g/cm(2); GG: 0.766 ± 0.004 g/cm(2), P < .001). Correspondingly, total hip BMD was significantly lower among C allele carriers (CC: 0.881 ± 0.016 g/cm(2); CG: 0.884 ± 0.005 g/cm(2); and GG: 0.906 ± 0.004 g/cm(2), P < .001). Finally, women homozygous for the variant C allele had an increased risk (hazard ratio 1.6, confidence interval 1.0-2.6, P < .05) of nonvertebral fractures.

CONCLUSION

This study demonstrates an association between a functional GIPR polymorphism Glu354Gln (rs1800437) and BMD and fracture risk. These findings further establish GIP to be involved in the regulation of bone density.

Probabilistic modelling of combined sewer overflow using the First Order Reliability Method

This paper presents a new and alternative method (in the context of urban drainage) for probabilistic hydrodynamical analysis of drainage systems in general and especially prediction of combined sewer overflow. Using a probabilistic shell it is possible to implement both input and parameter uncertainties on an application of the commercial urban drainage model MOUSE combined with the probabilistic First Order Reliability Method (FORM). Applying statistical characteristics on several years of rainfall, it is possible to derive a parameterization of the rainfall input and the failure probability and return period of combined sewer overflow to receiving waters can be found.

Relationship between bone strength and dual-energy X-ray absorptiometry measurements in pigs

Computed tomography and a 3-point bending test were performed on the metacarpal bones of adult production pigs to test the hypothesis that bone strength is strongly correlated with areal bone mineral density (BMD) in this population. The aim of the study was to subject material from adult production pigs grouped by BMD to 3-point bending, to test this hypothesis and determine any correlations. In all, 168 individual computed tomography scans and mechanical tests were performed on the collected material. For evaluation purposes, the material was divided into the categories low, medium, and high BMD (<1, 1 to 1.4, and >1.4 g/cm(2), respectively). The results showed a difference in the maximum load, in the stress at maximum load, and stiffness among each BMD group (P < 0.001) and in elastic modulus between the low BMD group and the 2 other groups (P < 0.001). A correlation between both intrinsic and extrinsic measures of bone strength and BMD was thus demonstrated. The projected change in each of the variables reported, for a 0.1 g/cm(2) alteration in BMD (within the BMD range evaluated in this study), is as follows: maximum load, 708 N; stress at maximum load, 50 N/mm(2); stiffness, 391.6 N/mm; and elastic modulus, 108 N/mm(2) (P < 0.001). The results confirm the relationship between BMD and bone strength and indicate that BMD screening can be used in fracture risk assessments in production pigs.

Development of the mesencephalic dopaminergic neuron system is compromised in the absence of neurogenin 2

Neurogenin 2 (Ngn2) is a proneural gene involved in neuronal differentiation and subtype specification in various regions of the nervous system. In the ventral midbrain, Ngn2 is expressed in a spatiotemporal pattern that correlates with the generation of mesencephalic dopaminergic (mesDA)neurons. We show here that lack of Ngn2 impairs the development of mesDA neurons, such that less than half of the normal mesDA neuron number remain in Ngn2 mutant mice at postnatal stages. Analysis of Ngn2mutant mice during mesDA neurogenesis show that medially located precursors are formed but are arrested in their differentiation at a stage when they have not yet acquired the characteristics of mesDA neuron precursors. Loss of Ngn2 function appears to specifically affect the generation of DA neurons, as the development of other types of neurons within the ventral midbrain is unaltered. Ngn2 is the first example of a gene expressed in progenitors in the ventricular zone of the mesDA neuron domain that is essential for proper mesDA neuron differentiation, and whose loss of function causes impaired mesDA neurogenesis without other major abnormalities in the ventral midbrain.

Bioavailability of calcium: comparison of calcium carbonate and milk and the effect of vitamin D, age, and sex using 24-hour urine calcium as a method

The aim of the present study was to compare the bioavailability of calcium from calcium carbonate and milk and to investigate if 1,200 IU of cholecalciferol a day increased intestinal absorption of calcium. Both young women and a group of older persons of both sexes were included to study the influence of age and sex. In total, 53 healthy women and men were included: a group of 23 younger women (median age 30) and an older group of 15 women and 15 men (median age 66). The study period was 4 weeks; each participant completed four treatment regimens randomly: CaCO(3), CaCO(3 )+ 1,200 IU of cholecalciferol, milk, and placebo. All regimens were distributed three times a day and consisted of 1,200 mg of elementary calcium. The 24-hour urine calcium excretion was used as a method. Total urinary calcium excretion rates (mmol/day) were as follows (mean +/- SD): placebo 4.41 +/- 2.17, milk 5.17 +/- 2.33, CaCO(3) 5.83 +/- 2.03, and CaCO(3 )+ D 6.06 +/- 2.46. All regimens compared to placebo were significant. Addition of cholecalciferol to the CaCO(3) regimen increased calcium excretion but insignificantly: 0.27 +/- 2.84 mmol/day. The increase in calcium excretion during the milk regimen was significant only for the old group: 0.96 vs. 0.28 mmol/day. No other difference was found according to age and sex. The bioavailability of calcium carbonate and milk was demonstrated. Additional cholecalciferol (1,200 IU) to individuals in positive calcium balance with serum 25(OH)D levels >50 nmol/L only marginally increased calcium absorption in a short-term intervention.

Chronic antidepressant treatments decrease pro-opiomelanocortin mRNA expression in the pituitary gland: effects of acute stress and 5-HT(1A) receptor activation

Consistent findings in depressed patients are hyperactivity in the hypothalamic-pituitary-adrenal (HPA) axis with high plasma concentrations of adrenocorticotropic hormone and cortisol. Long-term antidepressant treatments seem to normalize this hyperactivity, suggesting a link between the HPA axis and the action of antidepressant treatments. The present study was carried out to study the effects of antidepressant treatments on pro-opiomelanocortin (POMC) mRNA expression, with a focus on interaction with acute stress and 5-HT(1A) receptor activation. Male rats were treated for 21 days with saline, citalopram, fluoxetine, moclobemide or desipramine, and the expression of POMC mRNA in the anterior pituitary was analysed by semi-quantitative in situ hybridization. All antidepressants, but not saline, cocaine and haloperidol, reduced POMC mRNA expression. The decrease in POMC mRNA was not observed until 9 days of citalopram treatment. Decreased POMC mRNA levels were also observed after 14 days of repeated electroconvulsive stimulation. The decreased POMC mRNA levels did not affect the stress-induced POMC mRNA increase, measured following swim stress and restraint stress. Finally, using Fos as a marker for neural activity, we showed attenuation of 8-OH-DPAT-stimulated activity in the paraventricular nucleus following 21 days of citalopram treatment. In conclusion, antidepressant treatments decrease basal POMC mRNA expression without affecting the acute stress response, and the reduced POMC mRNA may be related to reduced 5-HT(1A)-stimulated hypothalamic output.

Role of GluR2 expression in AMPA-induced toxicity in cultured murine cerebral cortical neurons

alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R)-mediated neurotoxicity was studied in relation to subunit expression and the presence of Ca(2+)-permeable receptor channels. AMPA-mediated toxicity had two components: 1) a direct AMPA-R-mediated component, which was not due to Ca(2+) influx through voltage-gated Ca(2+) channels, reversal of the Na(+)/Ca(2+) exchanger or release of calcium from dantrolene-sensitive intracellular Ca(2+) stores, and 2) a minor, indirect component involving activation of NMDA receptor channels, because of glutamate release and removal of the Mg(2+) block of the NMDA receptor on AMPA-R stimulation. The involvement of Ca(2+) influx through AMPA-R was also examined. The number of neurons possessing Ca(2+)-permeable AMPA-R increased during culture development, concurrently with an increasing susceptibility for AMPA-induced toxicity during development. GluR2(R) levels also increased during development, and channel blockers of Ca(2+)-permeable AMPA-R lacking the GluR2(R) subunit (spermine and philanthotoxin) failed to prevent neurotoxicity or increases in [Ca(2+)](i). Thus, the direct AMPA-R-mediated toxicity may be explained by initiation of cell death by Ca(2+) fluxing through AMPA-R containing GluR2(R). The components of direct AMPA-R-mediated toxicity are proposed to be 1) toxicity mediated by GluR2(R)-lacking AMPA-R and 2) toxicity mediated by low-Ca(2+)-permeability AMPA-R containing GluR2(R).

Abnormal protein phosphorylation in post-mortem brain tissue from bipolar patients

Abnormal phosphorylation has been proposed to be involved in the pathogenesis of affective disorders. The present study investigated basal and cAMP-stimulated endogenous protein phosphorylation in human post-mortem brain tissue from bipolar and schizophrenic patients. Furthermore, basal kinase activity and stimulated protein kinase A activity were measured. The frontal and occipital cortex were analysed. Using [gamma-32P]ATP as phosphate donor, basal and cAMP-stimulated phosphorylation of endogenous proteins was measured in the absence or presence of 8-Br-cAMP, respectively. The proteins were separated on SDS-gels and the radioactivity in the individual bands was measured. We observed a significant reduction of 32P incorporation in three protein substrates (15, 16 and 21 kD) in frontal cortex of bipolar patients. However, there were no differences in the PKA activity between any of the groups. The present study demonstrates abnormal phosphorylation of specific proteins in brain tissue obtained from bipolar patients in comparison to schizophrenics and controls.

Subcutaneous bleeding: first sign of prostate cancer

We present here a case of subcutaneous bleeding being the first recognized sign of prostate cancer.

Depolarization-induced release of [(3)H]D-aspartate from GABAergic neurons caused by reversal of glutamate transporters

Cultured neocortical neurons, which predominantly consist of GABAergic neurons exhibit a pronounced stimulus-coupled GABA release. Since the cultures may contain a small population of glutamatergic neurons and the GABAergic neurons have a high content of glutamate it was of interest to examine if glutamate in addition to gamma-aminobutyric acid (GABA) could be released from these cultures. The neurons were preloaded with [(3)H]D-aspartate and subsequently its release was followed during depolarization induced by a high potassium concentration or the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor agonists, AMPA and kainate. Depolarization of the neurons with 55 mM potassium increased the release of [(3)H]D-aspartate by more than 10-fold. When the non-specific calcium-channel blockers cobalt or lanthanum were included in the stimulation buffer with potassium, the release of [(3)H]D-aspartate was decreased by about 40%. These results indicated that some of the released [(3)H]D-aspartate might originate from a vesicular pool. When AMPA was applied to the neurons, the release of [(3)H]D-aspartate was increased 2-fold and could not be prevented or decreased by addition of cobalt. Since AMPA has a rapid desensitizing effect on AMPA receptors, it was examined whether AMPA under non-desensitizing conditions was able to induce an increased release of [(3)H]D-aspartate as compared to the conditions of applying AMPA alone. The desensitization of AMPA receptors was blocked by 6-chloro-3,4-dihydro-3-(2-norbornen-5-yl)-2H-1,2, 4-benzothiadiazine-7-sulphonamide-1,1-dioxide (cyclothiazide). Under the non-desensitizing conditions, the AMPA-induced release of [(3)H]D-aspartate was highly enhanced showing about a 10-fold increase over basal release. Addition of cobalt or lanthanum did not decrease the amount of [(3)H]D-aspartate released, indicating that the release originated from a cytoplasmic pool. Kainate, which induces an almost non-desensitizing effect on AMPA receptors, showed similar results as observed for AMPA under non-desensitizing conditions. The NMDA receptor antagonist (5R,10 S)-(+)-5-methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) had only minor effects on the [(3)H]D-aspartate release induced by AMPA and kainate. Thus, the depolarization-induced release of [(3)H]D-aspartate from cultured GABAergic neurons appears to be caused mainly by reversal of the glutamate transporters.

Increased adenylyl cyclase type 1 mRNA, but not adenylyl cyclase type 2 in the rat hippocampus following antidepressant treatment

The adenylyl cyclase (AC) system is affected by several types of antidepressant treatments, and increased activity in this system is linked to the therapeutic action of antidepressants. The present study was undertaken to compare the effects of single-dose and long-term treatment with the selective serotonin reuptake inhibitor, citalopram (10 mg/kg, i.p.), on the AC system in the male rat brain of Wistar rats. Furthermore, we compared the effects of long-term citalopram and lithium treatments on the AC system. Long-term citalopram, but not single-dose administration, increased the AC type 1 mRNA in the hippocampus, whereas type 2 mRNA was unaffected. Long-term lithium treatment also increased AC1 in the hippocampus. However, long-term citalopram treatment did not increase AC type 1 protein, basal or forskolin-stimulated AC activity, but GTP increased AC activity in the hippocampus. This may indicate enhanced AC/G protein coupling. Thus, citalopram may increase cAMP signalling by acting on components of the AC system without affecting the protein level of the AC type 1.

D-fenfluramine activates rat oxytocinergic and vasopressinergic neurons through different mechanisms

Activation of serotonin neurotransmission produces increase of plasma oxytocin, prolactin, vasopressin and ACTH levels. Using dual-immunocytochemistry, the number of oxytocinergic neurons in the hypothalamic magnocellular nuclei co-storing Fos after administration of D-fenfluramine was found to be 15-fold higher compared to vehicle, comprising about 30% of the total number of these neurons. Vasopressinergic neurons were virtually not affected. These results show that serotonergic neurotransmission induces Fos transcription in oxytocinergic neurons that may lead to a release of oxytocin to the general circulation, whereas vasopressinergic neurons are activated through another mechanism.

Acute and long-term treatments with the selective serotonin reuptake inhibitor citalopram modulate the HPA axis activity at different levels in male rats

It is well established that the maximal therapeutic effect of selective serotonin reuptake inhibitors (SSRI) are achieved in depressive patients after several weeks of treatment, but the adaptive processes leading to the therapeutic effects are unclear. It has been shown that hyperactivity in the hypothalamic-pituitary-adrenal (HPA) axis in depressive patients is affected by long-term antidepressant treatment. These changes occur in association with the mood normalising effect, suggesting that antidepressants affect the HPA axis and this effect is associated with the therapeutic effect. Male Wistar rats were treated with the SSRI, citalopram, to investigate time-related changes in components that may be involved in the desensitization of the HPA axis. A single injection of citalopram (10 mg/kg, s.c.), increased the plasma levels of ACTH and corticosterone in a dose-dependent manner and increased the number of c-Fos containing cells in the hypothalamic paraventricular nucleus. A daily treatment with the same compound (10 mg/kg, s.c.) for 14 days decreased the expression of POMC mRNA ( approximately 40%). In addition, a blunted response to citalopram was observed in animals long-term treated with citalopram. Also CRF-stimulated cAMP accumulation in the pituitary was altered. In conclusion, acute citalopram activated the HPA-axis at the hypothalamic level and long-term citalopram treatment desensitized the HPA-axis at the pituitary level. These results support the hypothesis that the therapeutic effects of long-term antidepressant treatments reduce HPA axis responsiveness.

Role of desensitization and subunit expression for kainate receptor-mediated neurotoxicity in murine neocortical cultures

The neurotoxic actions of kainate and domoate were studied in cultured murine neocortical neurons at various days in culture and found to be developmentally regulated involving three components of neurotoxicity: (1) toxicity via indirect activation of N-methyl-D-aspartate (NMDA) receptors, (2) toxicity mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, and (3) toxicity that can be mediated by kainate receptors when desensitization of the receptors is blocked. The indirect action at NMDA receptors was discovered because (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-im ine (MK-801), an NMDA receptor antagonist, was able to block part of the toxicity. The activation of NMDA receptors is most likely a secondary effect resulting from glutamate release upon kainate or domoate stimulation. 1-(4-Aminophenyl)-3-methylcarbamyl-4-methyl-3,4-dihydro-7,8-ethyle nedioxy-5H-2,3-benzodiazepine (GYKI 53655), a selective AMPA receptor antagonist, abolished the remaining toxicity. These results indicated that kainate- and domoate-mediated toxicity involves both the NMDA and the AMPA receptors. Pretreatment of the cultures with concanavalin A to prevent desensitization of kainate receptors led to an increased neurotoxicity upon stimulation with kainate or domoate. In neurons cultured for 12 days in vitro a small but significant neurotoxic effect was observed when stimulated with agonist in the presence of MK-801 and GYKI 53655. This indicates that the toxicity is produced by kainate receptors in mature cultures. Examining the subunit expression of the kainate receptor subunits GluR6/7 and KA2 did, however, not reveal any major change during development of the cultures.

Development of calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in cultured neocortical neurons visualized by cobalt staining

The developmental expression of calcium (Ca2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors in cultured neocortical neurons was evaluated by using cobalt uptake, a histochemical method that identifies cells expressing Ca2+-permeable, non-N-methyl-D-aspartate (non-NMDA) receptors. At a concentration of 500 microM, AMPA was found to stimulate cobalt uptake only late in development, resulting in staining of 2.7%+/-0.3% of the neurons maintained in culture for 12 days in vitro (DIV). When AMPA receptor desensitization was blocked with 50 microM cyclothiazide, the developmental profile of cobalt uptake mediated by 25 microM AMPA changed dramatically. The cobalt staining now appeared in young cultures (5 DIV), and the percentage of stained cells increased from 3.4%+/-0.2% at 5 DIV to 21.7%+/-1.6% at 12 DIV. The effect of 200 microM kainate was similar to that seen with 25 microM AMPA plus 50 microM cyclothiazide, resulting in 17.7%+/-0.3% stained neurons at 12 DIV. The cobalt uptake was specific to AMPA and kainate receptors because NMDA receptors and voltage-gated calcium channels were found not to mediate any cobalt staining. In addition, 10 microM 6-nitro-7-sulphamoylbenzo-[f]-quinoxaline-2,3-dione (NBQX) was able to prevent all staining at 5 and 8 DIV and most of the staining at 12 DIV, indicating that the non-NMDA ionotropic glutamate receptors are involved in cobalt uptake into the neurons. The AMPA receptor-selective antagonist GYKI 53655 was used to differentiate between cobalt influx through AMPA- or kainate-preferring receptors. After pretreatment with concanavalin A (con A), an inhibitor of kainate receptor desensitization, cobalt uptake was assessed after stimulation by 200 microM kainate in the presence of 25 microM GYKI 53655. No cobalt staining was observed under these conditions, indicating that most if not all of the cobalt influx induced by kainate was mediated through AMPA receptor channels.

Identification of an erythrocyte binding peptide from the erythrocyte binding antigen, EBA-175, which blocks parasite multiplication and induces peptide-blocking antibodies

A biotinylated peptide covering a sequence of 21 amino acids (aa) from the erythrocyte binding antigen (EBA-175) of Plasmodium falciparum bound to human glycophorin A, an erythrocyte receptor for merozoites, as demonstrated by enzyme-linked immunosorbent assay (ELISA) and to erythrocytes as demonstrated by flow cytometry analysis. The peptide, EBA(aa1076-96), also bound to desialylated glycophorin A and glycophorin B when tested by ELISA. The peptide blocked parasite multiplication in vitro. The glycophorin A binding sequence was further delineated to a 12-aa sequence, EBA(aa1085-96), by testing the binding of a range of truncated peptides to immobilized glycophorin A. Our data indicate that EBA(aa1085-96) is part of a ligand on the merozoite for binding to erythrocyte receptors. This binding suggests that the EBA(aa1085-96) peptide is involved in a second binding step, independent of sialic acid. Antibody recognition of this peptide sequence may protect against merozoite invasion, but only a small proportion of sera from adults from different areas of malaria transmission showed antibody reactivities to the EBA(aa1076-96) peptide, indicating that this sequence is only weakly immunogenic during P. falciparum infections in humans. However, Tanzanian children with acute clinical malaria showed high immunoglobulin G reactivity to the EBA(aa1076-96) peptide compared to children with asymptomatic P. falciparum infections. The EBA(aa1076-96) peptide sequence from EBA-175 induced antibody formation in mice after conjugation of the peptide with purified protein derivative. These murine sera inhibited EBA(aa1076-96) peptide binding to glycophorin A.

AMPA receptor mediated excitotoxicity in neocortical neurons is developmentally regulated and dependent upon receptor desensitization

AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) excitotoxicity was examined in cultured neocortical neurons using the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to measure cell viability. Neurons were exposed to AMPA at different culture periods during development of the neurons. In order to describe the pharmacology of AMPA-mediated toxicity, several glutamate receptor antagonists were used: MK-801, NS 394, NBQX, GYKI 52466, GYKI 53405 and GYKI 53655. Increased excitotoxicity was observed when cortical neurons cultured for 5, 8 and 12 days in vitro (DIV) were exposed to a high concentration of AMPA (500 microM) for 6 h. However, only at DIV 12 was part of the toxicity mediated directly through AMPA receptors since 10 microM MK-801 blocked all AMPA toxicity at DIV 5 and 8, but only some of the AMPA response at DIV 12. This indicated that NMDA receptors were being activated, causing some of the observed toxicity. The high dose of AMPA was not sufficient to damage all neurons since 59% remained viable after exposure to AMPA even for neurons that were cultured for 12 DIV. Since it is known that both glutamate and AMPA activate AMPA receptors with a fast and rapidly desensitizing response, this could explain the relatively low toxicity produced by 500 microM AMPA. This was investigated by blocking AMPA receptor desensitization with cyclothiazide. Using a lower concentration (25 microM) of AMPA, addition of 50 microM cyclothiazide increased the AMPA induced excitotoxicity in cultured cortical neurons at all DIV except for DIV 2. This combination of AMPA + cyclothiazide yielded 77% cell death for DIV 12 cultures. In contrast to the results observed with 500 microM AMPA, the neurotoxicity mediated directly by AMPA receptors when desensitization was blocked was seen as early as 5 DIV since 10 microM MK-801 did not completely block the response whereas 10 microM NBQX did. The 2,3-benzodiazepine GYKI compounds, which have been reported to be selective non-competitive AMPA receptor antagonists, were here observed to block the AMPA toxicity with the following rank order: GYKI 53655 > GYKI 52466 > or = GYKI 53405, which is in agreement with their published potencies.

Continuous culture of Plasmodium falciparum: its impact on malaria research

The methods developed by us in 1976 for the continuous culture of the erythrocytic stages of Plasmodium falciparum make this organism available to a large variety of scientists. As a result, much has been learned about P. falciparum during the past 20 years. Here we attempt to emphasize recent developments in the diverse aspects for which the culture method has been particularly useful: chemotherapy; drug resistance; vaccine development; pathogenesis; export of proteins into the host cell; cell biology, the mitochondrion and the plastid; innate resistance involving mutant human erythrocytes; gametocytogenesis; genetics, transfection; molecular biology; biochemistry; extracellular cultivation.

Antibody responses to Rhoptry-Associated Protein-1 (RAP-1) of Plasmodium falciparum parasites in humans from areas of different malaria endemicity

Plasma IgM and IgG antibody reactivities against the recombinant Plasmodium falciparum protein, Rhoptry Associated Protein-1 (rRAP-1) were measured by ELISA in individuals from Sudan, Indonesia, Kenya and The Gambia living in areas of different malaria endemicity. IgG and IgM reactivities to rRAP-1 increased with malaria endemicity. IgG reactivities were associated with spleen rates in Indonesia with high malaria endemicity while IgM reactivities were associated with spleen rates in Kenya with low malaria endemicity. IgG and IgM reactivities to rRAP-1 increased during acute episodes of P. falciparum malaria in Sudanese adults and IgG reactivities remained high one month after treatment in all adults tested. Antibody reactivities to rRAP-1 in Gambian children in the dry season were higher in children with parasitaemia than in children without detectable parasitaemia. Antibody reactivities were not associated with protection against clinical episodes in the following rainy season but higher antibody reactivities were detectable at the end of the rainy season. There was no difference in antibody reactivity to rRAP-1 between Gambian children with mild or severe malaria.

Altered protein phosphorylation in the rat brain following chronic lithium and carbamazepine treatments

Lithium and carbamazepine (CBZ) alter levels of specific kinase-activating second messengers generated by adenylate cyclases and the phosphoinositide system. Thus, lithium and CBZ may change endogenous protein phosphorylation mediated by cyclic AMP-dependent protein kinase (PKA) and protein kinase C (PKC). The present study aimed at comparing the chronic effects of lithium and CBZ on protein phosphorylation in the rat brain by using quantitative autoradiography. Long-term treatments yielded plasma levels within the therapeutic range. In the particulate hippocampal fraction PKA-mediated phosphorylation of a 42 kDa protein and PKC-mediated phosphorylation of a 88 kDa protein were decreased after lithium treatment. In the cortical particulate fraction approximately 30% reduction in the PKA-mediated protein phosphorylation of several proteins was observed after lithium and CBZ treatments. In the same fraction, CBZ treatment significantly reduced PKC-mediated phosphorylation of several substrates by 30-40%. PKA activity was significantly reduced in cortex, but not in the hippocampus. Thus, both drugs exhibited fraction and region specificities.

Human T-cell recognition of synthetic peptides representing conserved and variant sequences from the merozoite surface protein 2 of Plasmodium falciparum

Merozoite surface protein 2 (MSP2) is a malaria vaccine candidate currently undergoing clinical trials. We analyzed the peripheral blood mononuclear cell (PBMC) response to synthetic peptides corresponding to conserved and variant regions of the FCQ-27 allelic form of MSP2 in Ghanaian individuals from an area of hyperendemic malaria transmission and in Danes without exposure to malaria. PBMC from 20-39% of Ghanaians responded to each of the peptides by proliferation and 29-36% had PBMC which produced interferon-gamma (IFN-gamma) in response to peptide stimulation. In Danes, there was no proliferation to two of the peptides and only PBMC from 5% of the individuals proliferated to the other three peptides. IFN-gamma production was not detected to any peptide. In both Danes and Ghanaians in only a few instances was IL-4 detected in the PBMC cultures. Overall PBMC from 79% of the Ghanaians responded by proliferation and/or cytokine secretion to at least one of three peptides tested, whereas responses were only observed in 14% of Danes (P = 0.002). These data suggest that the Ghanaians had expanded peripheral blood T-cell populations recognizing the peptides as a result of natural infection. The findings are encouraging for the development of a vaccine based on these T-epitope containing regions of MSP2, as the peptides were broadly recognized suggesting that they can bind to diverse HLA alleles and also because they include conserved MSP2 sequences. Immunisation with a vaccine construct incorporating the sequences present in these peptides could thus be expected to be immunogenic in a high percentage of individuals and lead to the establishment of memory T-cells, which can be boosted through natural infection.

Molecular cloning and characterization of a cDNA for the highly conserved HMG-like protein (Pf16) gene of Plasmodium falciparum

A cDNA clone (PfHB3-2-4) of 1538 bp corresponding to the highly conserved HMG-like protein (Pf16) was isolated. However, northern analysis suggests that the mRNA is about 2.2 to 2.3 kb. Analysis by RT-PCR indicated that the 0.6 to 0.7 kb sequence missing in the cDNA maps to the 3' end, suggesting that the cDNA is terminated within the 26 adenosine residues that are in the middle of the Pf16 sequence. The most unique feature about this cDNA is the presence of two open reading frames (ORF), one from nucleotides 91 to 927 and the other starting from 1421. The second ORF corresponds to Pf16. Expression of the cDNA clones in Escherichia coli and translation in rabbit reticulocytes of RNA transcribed from the T7 promoter of the cDNA clones revealed that only the 3' end Pf16 is translated from this mRNA. Further experiments with antisense oligonucleotides specific for Pf16 indicated that the Pf16 protein serves an important function in the life cycle of the parasite.

Use of random amplified polymorphic DNA (RAPD) technique in inheritance studies of Plasmodium falciparum

Effectiveness of random amplified polymorphic DNA (RAPD), a technique using 1 10-base primer to amplify random segments of genomic DNA, and some of its possible uses were tested in the A + T-rich genome of Plasmodium falciparum. The best concentrations of MgCl2, 60% G + C primer, and DNA were determined to be 4.0 mM, 0.4 microM, and 90-180 ng/15 microliters reaction, respectively. Use of 30% G + C primers did not allow amplification to occur. Application of RAPD to DNA of parent and progeny clones from a P. falciparum cross showed that polymorphisms identified in the parentals and tracked in the progeny were inherited in a Mendelian fashion and that RAPD-identified polymorphisms could be used as genetic markers. Some of these polymorphic markers were located on more than 1 chromosome, whereas others were specific for a single chromosome. Two of these markers, each located on chromosome 3 of 1 of the parental parasites, were missing from 2 of the 18 progeny, suggesting that deletions, or crossover events had occurred. RAPD markers also identified a higher number of nonparental-type progeny than expected, thus confirming previous observations for high genetic variability in malaria parasites.

Antibody reactivities to glutamate-rich peptides of Plasmodium falciparum parasites in humans from areas of different malaria endemicity

Synthetic P. falciparum peptides were evaluated as tools in epidemiological investigations of malaria. Plasma IgM and IgG antibody reactivities against synthetic peptides covering sequences of glutamate-rich protein (GLURP) and acidic-basic repeat antigen (ABRA) were measured by ELISA in individuals from malaria-endemic areas of Sudan, Indonesia and The Gambia to study antibody responses to these peptides in donors living in areas of different malaria endemicity. IgG and IgM reactivities to the peptides increased with malaria endemicity, although there were no differences in reactivities to the GLURP peptide between non-exposed donors and donors living in areas of low malaria endemicity. IgG reactivities to the GLURP peptide in Sudanese adults were high one month after treatment in all adults tested, while IgG reactivities to the ABRA peptide were infrequent. IgM responses to the peptides tested were shortlived in most patients. In Gambian children with malaria, IgM reactivities but not IgG antibody reactivities against the ABRA peptide were higher in those with mild malaria than in those with severe malaria. The peptides may be useful in future epidemiological studies, especially in areas of low malaria endemicity.

Augmented hypoxic cerebral vasodilation in men during 5 days at 3,810 m altitude

The fractional increase in cerebral blood flow (CBF) velocity (VCBF) from the control value with 5-min steps of isocapnic hypoxia and hyperoxic hypercapnia was measured by transcranial Doppler in six sea-level native men before and during a 5-day sojourn at 3,810 m altitude to determine whether cerebral vasoreactivity to low arterial O2 saturation (SaO2) gradually increased [as does the hypoxic ventilatory response (HVR)] or diminished (adapted, in concert with known slow fall of CBF) at altitude. A control resting PCO2 value was chosen each day during preliminary hyperoxia to set ventilation at 140 ml.kg-1.min-1 for this and the parallel HVR study, attempting to establish control cerebrospinal fluid (CSF) and brain extracellular fluid pH values unaltered by acclimatization. The relationship of CBF to SaO2 was nonlinear, steepening at a lower SaO2. A hyperbolic equation was used to describe hypoxic cerebrovascular reactivity: fractional VCBF = x[60/ (SaO2-40)-1], where X is the fractional increase of VCBF at 70%.X rose from 0.346 +/- 0.104 (SD) at sea level to 0.463 +/- 0.084 on altitude day 5 (P < 0.05 by paired t-test, justified by the a priori experimental plan). For comparison with CO2 sensitivity, from these X values, we estimate the rise in CBF in response to a 1% fall in SaO2 at 80% to be 1.30% at sea level and 1.74% after 5 days at altitude. CBF sensitivity to increased end-tidal PCO2 rose from 4.01 +/- 0.62%/Torr at sea level to 5.12 +/- 0.79%/Torr on day 5 (P < 0.05), as expected, at the lower PCO2 due to the logarithmic relationship of PCO2 to CSF pH. This change was not significant after correction to log PCO2. We conclude that the cerebral vascular response to acute isocapnic hypoxia may increase during acclimatization at high altitude. The mechanism is unknown but is presumably unrelated to the parallel carotid chemosensitization that, in these subjects, increased the HVR by 60% in the same 5-day period from 0.91 +/- 0.38 to 1.46 +/- 0.59 l.min-1.% fall in SaO2-1).

Catabolism of indole-3-acetic acid and 4- and 5-chloroindole-3-acetic acid in Bradyrhizobium japonicum

Some strains of Bradyrhizobium japonicum have the ability to catabolize indole-3-acetic acid. Indoleacetic acid (IAA), 4-chloro-IAA (4-Cl-IAA), and 5-Cl-IAA were metabolized to different extents by strains 61A24 and 110. Metabolites were isolated and analyzed by high-performance liquid chromatography and conventional mass spectrometry (MS) methods, including MS-mass spectroscopy, UV spectroscopy, and high-performance liquid chromatography-MS. The identified products indicate a novel metabolic pathway in which IAA is metabolized via dioxindole-3-acetic acid, dioxindole, isatin, and 2-aminophenyl glyoxylic acid (isatinic acid) to anthranilic acid, which is further metabolized. Degradation of 4-Cl-IAA apparently stops at the 4-Cl-dioxindole step in contrast to 5-Cl-IAA which is metabolized to 5-Cl-anthranilic acid.

High proportion of subclinical Plasmodium falciparum infections in an area of seasonal and unstable malaria in Sudan

In the present longitudinal study, a cohort (n = 98) of children and adults 5-30 years of age living in an area of highly seasonal and unstable malaria transmission were followed for malaria morbidity during several successive transmission seasons. Based on morbidity surveillance during 1993 and measurements of antibody titers to the Plasmodium falciparum ring-infected erythrocyte surface antigen (Pf155/RESA), the cohort was divided into three groups: those who had at least one episode of clinical malaria (Group 1, n = 31), those who did not suffer from clinical malaria but had (Group 2, n = 63) or had not (Group 3, n = 4) a significant increase in antibody titers against the Pf155/RESA antigen. This increase was defined as equal to or greater than a four-fold increase in antibody titer in samples from same individuals taken at the beginning and the end of the malaria transmission season. Such increases in specific antibody levels suggested that the donors had been exposed to a P. falciparum blood-stage infection. Measurements of antibody titers to a peptide derived from the glutamate-rich protein exoantigen gave data parallel to those for Pf155/RESA. A surprisingly high fraction of individuals in the study cohort (approximately 66%) showed evidence of infection without ensuing clinical disease (Group 2).

[Episodic hypoxemia and coinciding ECG changes after acute myocardial infarction]

This study was conducted to document the trend in arterial hypoxaemia and electrocardiographic (ECG) abnormalities on second to sixth night after acute myocardial infarction (AMI). Nineteen consecutive patients with AMI were monitored continuously during the night with a Holter tape recorder and a pulse oxymeter. Five patients had > 30 episodic oxygen desaturations of > or = 5%, and many patients had episodes with oxygen desaturations < 80% ranging from 46-61% (from 7/15-11/18) during the nights of monitoring. Constant hypoxaemia was found in 11-13% of the patients. Many patients had simultaneous occurrence of episodic hypoxaemia and episodic sinustachycardia, ST-deviation and arrhythmias, giving a summarized simultaneous occurrence of episodic hypoxaemia and ECG-abnormalities ranging from 13/18 (72%) patients on the third night to 7/15 (46%) patients on the sixth night. Episodic and constant hypoxaemia are thus common during the first week after AMI. Episodic hypoxaemia was associated with ECG-abnormalities in the majority of patients.

Evidence of endothelial inflammation, T cell activation, and T cell reallocation in uncomplicated Plasmodium falciparum malaria

To explain the observation that acute Plasmodium falciparum malaria is associated with a transient inability of peripheral blood cells to respond to antigenic stimulation in vitro, we have postulated the disease-induced reallocation of peripheral lymphocytes, possibly by adhesion to inflamed endothelium. We measured plasma levels of soluble markers of endothelial inflammation and T cell activation in 32 patients suffering from acute, uncomplication P. falciparum malaria, as well as in 10 healthy, aparasitemic control donors. All donors were residents of a malaria-endemic area of Eastern State Sudan. In addition, we measured the T cell surface expression of the interleukin-2 receptor (CD25) and the lymphocyte function-associated antigen (LFA-1; CD11a/CD18). We found that the plasma levels of all inflammation and activation markers were significantly increased in the malaria patients compared with the control donors. In addition, we found a disease-induced depletion of T cells with high expression of the LFA-1 antigen, particularly in the CD4+ subset. The results obtained provide further support for the hypothesis of T cell reallocation to inflamed endothelium in acute P. falciparum malaria.

Use of random amplified polymorphic DNA analysis to compare Babesia bovis and B. bigemina isolates

Random amplified polymorphic DNA analysis provides characteristic fingerprints for Babesia bovis and B. bigemina. This genetic profile reflects similarities and minor differences between closely related regional isolates and the greater diversity representative of species from distant geographic locations.

Differential T-cell expression of LFA-1 in residents from Africa and Denmark. Description of the phenomenon and its possible basis

All circulating T cells constitutively express the adhesion molecule leukocyte function-associated antigen 1 (LFA-1; CD11a/CD18) at either low or high surface density. In the present paper we have compared the expression of the LFA-1 alpha-chain CD11a on peripheral T cells obtained from indigenous Africans with permanent residence in Africa to T cells from indigenous Danes with permanent residence in Denmark. The Africans had a higher percentage of T cells with high CD11a expression than did Danish donors. The difference was evident in both the CD3-, CD4+, and CD8+ subsets. The difference did not appear to reflect a higher degree of peripheral T-cell activation in the African donors, as T-cell expression of the activation marker IL-2 receptor (CD25) was similar in the two groups. Furthermore, we observed no apparent correlation between CD3+ CD11a(hi) and CD3+ CD25+ values in individual donors. LFA-1 expression on T cells obtained from expatriate Africans with long-term residence in Denmark resembled that of Danish permanent residents more than that of Africans with permanent residence in Africa. In addition, T cells obtained from two expatriate Danes with long-term residence in rural Africa were phenotypically similar to those from African permanent residents. The data suggest that the observed difference is environmental rather than ethnic and may reflect the degree of exposure to infectious agents.