Mapping of ATP, glucose, glycogen, and lactate concentrations within the arterial wall

OBJECTIVE

In large- and medium-sized arteries, the diffusion distances for oxygen and nutrients are long. This has been suggested to make these vessels prone to develop local energy metabolic deficiencies that could contribute to atherogenesis. To validate this hypothesis, we introduced a new method to measure energy metabolites within the arterial wall at high spatial resolution.

METHODS AND RESULTS

Bioluminescence imaging was used to quantify local metabolite concentrations in cryosections of snap frozen (in vivo) and incubated pig carotid artery rings. Incubation at hypoxia resulted in increased lactate concentrations, whereas ATP, glucose, and glycogen concentrations were decreased, especially in the mid media, where concentrations of these metabolites were close to zero. In snap frozen arteries, glycogen concentrations were markedly higher in deep layers of the media than toward the lumen. ATP, glucose, and lactate were more homogenously distributed.

CONCLUSIONS

Bioluminescence imaging is a new and powerful tool to assess arterial wall energy metabolism at high spatial resolution. Our experiments demonstrate heterogeneous distributions of energy metabolites under hypoxic in vitro conditions. Furthermore, we show that glycogen concentrations are higher in deep medial layers in vivo. This might represent a local adaptation to a low-oxygen microenvironment.

Pathophysiology of meningococcal meningitis and septicaemia

Neisseria meningitidis is remarkable for the diversity of interactions that the bacterium has with the human host, ranging from asymptomatic nasopharyngeal colonisation affecting virtually all members of the population; through focal infections of the meninges, joints, or eye; to the devastating and often fatal syndrome of meningococcal septic shock and purpura fulminans.

Sibling familial risk ratio of meningococcal disease in UK Caucasians

To quantify the host genetic component of meningococcal disease (MD) susceptibility, the sibling risk ratio (lambdaS) was calculated as the ratio of observed MD cases among 845 siblings of 443 UK Caucasian cases to that expected, calculated from age-calendar year specific rates for England and Wales. Twenty-seven siblings contracted MD compared with an expected 0.89, generating a lambdaS value of 30.3. Overestimation of lambdaS due to Neisseria meningitidis exposure was minimized by excluding siblings with MD onset within set time points of the index case. Irrespective of whether siblings contracted MD more than 1, 3, 6, 9 or 12 months after the index case, the lambdaS varied slightly (lambdaS range: 8.2-11.9), suggesting that host genetic factors may contribute approximately one third of the total lambdaS. Social class distribution did not differ between MD cases and the general population of England and Wales. This study is the first to calculate lambdaS for MD and establishes that susceptibility to MD has a significant host genetic component.

Severe P. falciparum malaria in Kenyan children: evidence for hypovolaemia

BACKGROUND

The role of volume resuscitation in severe Plasmodium falciparum malaria is controversial.

AIM

To examine the role of hypovolaemia in severe childhood malaria.

STUDY DESIGN

Retrospective review.

METHODS

We studied 515 children admitted with severe malaria to a high-dependency unit (HDU) in Kilifi, Kenya. On admission to the HDU, children underwent a further assessment of vital signs and a standard clinical examination.

RESULTS

Factors associated with a fatal outcome included deep breathing or acidosis (base excess below -8), hypotension (systolic blood pressure <80 mmHg), raised plasma creatinine (>80 micro mol/l), low oxygen saturation (<90%), dehydration and hypoglycaemia (<2.5 mmol/l). Shock was present in 212/372 (57%) children, of whom 37 (17.5%) died, and was absent in 160, of who only 7 (4.4%) died (chi(2) = 14.9; p = 0.001).

DISCUSSION

Impaired tissue perfusion may play a role in the mortality of severe malaria. Moreover, volume resuscitation, an important life-saving intervention in children with hypovolaemia, should be considered in severe malaria with evidence of impaired tissue perfusion.

A comparative biomechanical study of the strength of the bony patella following dome cut or uniplanar cut in total knee arthroplasty

This study was designed to investigate whether there is a difference in the strength of the bony patella following preparation either with a dome configuration or with a regular uniplanar cut in total knee arthroplasty. For each test 4 cadaveric patellae were used. Two of the 4 patellae were prepared with a regular uniplanar cut and 2 were prepared into a dome shape with a circumferential wall, using a concave reamer. The thickness of each patella after preparation was [figure 1 & 2: see text] 15 mm. The tests were performed using an impact drop weight apparatus. In the first two tests, which tested the resistance of the patella to tensile force and evaluated the strength of the patella by impact load while under tension, the soft tissues were torn, with no harm to the bony patella. In the third test, which evaluated the resistance of the patella without tension against impact load, the force required to fracture the dome-shaped patella was greater than for the traditional uniplanar cut (500 Kg vs 350 Kg). Dome shape with circumferential wall preparations of the bony patella in total knee arthroplasty were stronger in resisting external impact than the conventional uniplanar cut patella. This established the rationale for our use of the dome-shaped patella implant with a concave undersurface.

Analysis of pathogen-host cell interactions in purpura fulminans: expression of capsule, type IV pili, and PorA by Neisseria meningitidis in vivo

The pattern of meningococcal surface structure expression in different microenvironments following bloodstream invasion in vivo is not known. We used immunohistochemistry to determine the expression of capsule, type IV pili, and PorA by meningococci residing in the skin lesions of children with purpura fulminans. All the skin biopsy samples showed evidence of thrombosis and, frequently, a perivascular inflammatory cell infiltrate consisting of neutrophils (elastase positive) and monocytes/macrophages (CD68 positive). Modified Gram staining revealed 20 to over 100 gram-negative diplococci in each 4-microm-thick section, usually grouped into microcolonies. Immunoperoxidase staining demonstrated that the invading meningococci expressed PorA, capsule, and type IV pilin. Expression of these antigens was not restricted to any particular environment and was found in association with meningococci located in leukocytes, small blood vessels, and the dermal interstitium. Confocal laser scanning microscopy demonstrated coexpression of pilin and capsule by numerous microcolonies. However, there was some discordance in capsule and pilin expression within the microcolonies, suggesting phase variation. The strategy employed in this study will be helpful in investigating invasive bacterial diseases where antigenic and phase variation has a significant impact on virulence and on vaccine design.

Kawasaki disease: an evidence based approach to diagnosis, treatment, and proposals for future research

This article proposes a clinical guideline for the diagnosis and treatment of Kawasaki disease in the UK based on the best available evidence to date, and highlights areas of practice where evidence is anecdotal or based on retrospective data. Future research as proposed by the London Kawasaki Disease Research Group is outlined, and clinicians are invited to prospectively enroll their suspected cases into this collaborative research project.

Isolation and community: a review of the role of gap-junctional communication in embryonic patterning

Gap junctions are specialized channels formed between the membranes of two adjacent cells. They permit the direct passage of small molecules from the cytosol of one cell to that of its neighbor, and thus form a system of cell-cell communication that exists alongside familiar secretion/receptor signaling. Gap junction states can be regulated at many levels by factors such as membrane voltage, pH, phosphorylation state, and biochemical signals. Because of the rich potential for regulation of junctional conductance, and directional and molecular gating (specificity), gap junctional communication (GJC) plays a crucial role in many aspects of normal tissue physiology, as well as in tumor progression. However, arguably the most exciting role for GJC is in the regulation of information flow that takes place during embryonic development. This review summarizes the current knowledge of how GJC controls various aspects of embryonic morphogenesis in both vertebrate and invertebrate systems. Modern molecular embryology approaches have complemented biophysical and ultrastructural data, and we are beginning to unravel the patterning roles of GJC in embryonic events such as the patterning of the embryonic left-right axis, as well as the morphogenesis of the heart and limb. Proteins from the Connexin (Cx) gene family, as well as innexins and ductin, are now beginning to be understood as the basis for GJC underlying important embryonic patterning events.

Left-right asymmetry determination in vertebrates

A distinctive and essential feature of the vertebrate body is a pronounced left-right asymmetry of internal organs and the central nervous system. Remarkably, the direction of left-right asymmetry is consistent among all normal individuals in a species and, for many organs, is also conserved across species, despite the normal health of individuals with mirror-image anatomy. The mechanisms that determine stereotypic left-right asymmetry have fascinated biologists for over a century. Only recently, however, has our understanding of the left-right patterning been pushed forward by links to specific genes and proteins. Here we examine the molecular biology of the three principal steps in left-right determination: breaking bilateral symmetry, propagation and reinforcement of pattern, and the translation of pattern into asymmetric organ morphogenesis.

Immunogenicity of a serogroup B meningococcal vaccine against multiple Neisseria meningitidis strains in infants

BACKGROUND

The serogroup B meningococcus is responsible for the majority of cases of meningococcal disease in temperate countries. Infants and young children <2 years of age are at greatest risk of disease. This study assessed the immunogenicity in infants of a serogroup B meningococcal outer membrane protein vaccine that has been used extensively in disease outbreaks in Cuba and several Latin American countries and shown to be efficacious in teenagers.

METHOD

One hundred five healthy infants entering the routine vaccination schedule in Havana, Cuba, were given either 2 or 3 doses of the serogroup B meningococcal vaccine VA-MENGOC-BC at 3.5, 5.5 and 7.5 months of age. Immune response pre- and postvaccination was determined by the conventional serum bactericidal assay (SBA), a more sensitive novel whole blood bactericidal assay (WBA) and immunoglobulin ELISA.

RESULTS

In 52 and 46% of infants >50% killing of the vaccine serogroup B strain (B:4:P1.19,15) and serogroup C strain, respectively, was demonstrated by the WBA after 2 doses of the vaccine. Serum bactericidal activity (4-fold increase in titer) was induced in only 27% against the vaccine serogroup B strain and in 14% against the serogroup C strain. The changes in WBA and SBA were mirrored by the serogroup B and C immunoglobulin ELISA. Cross-reactive immunogenicity against other (heterologous) serogroup B strains was demonstrated for one of the four further strains assessed by WBA. By age 16 to 18 months SBA, WBA and ELISA responses had declined considerably. The addition of a third dose of vaccine did not appear to significantly influence immunogenicity at 17 months of age.

CONCLUSION

The serogroup B outer membrane protein vaccine VA-MENGOC-BC induces a demonstrable immune response in infants against both the serogroup B vaccine strain and against a serogroup C strain. Cross-reactive immunogenicity against other (heterologous) serogroup B strains is limited in this age group.

Reduction in case fatality rate from meningococcal disease associated with improved healthcare delivery

BACKGROUND AND AIMS

The case fatality rate from meningococcal disease (MD) has remained relatively unchanged in the post antibiotic era, with 20-50% of patients who develop shock still dying. In 1992 a new paediatric intensive care unit (PICU) specialising in MD was opened. Educational information was disseminated to local hospitals, and a specialist transport service was established which delivered mobile intensive care. The influence of these changes on mortality of children with MD was investigated.

METHODS

A total of 331 consecutive children with meningococcal disease admitted to the PICU between 1992 and 1997 were studied. Severity of the disease on admission was assessed using the paediatric risk of mortality (PRISM) score. Logistic regression analysis was used to correct for clinical severity, age, and sex; death was the outcome, and year of admission, a temporal trend variable, was the primary exposure.

RESULTS

The case fatality rate fell year on year (from 23% in 1992/93 to 2% in 1997) despite disease severity remaining largely unchanged. After adjustment for age, sex, and disease severity, the overall estimate for improvement in the odds of death was 59% per year (odds ratio for the yearly trend 0.41).

CONCLUSIONS

A significant improvement in outcome for children admitted with MD to a PICU has occurred in association with improvements in initial management of patients with MD at referring hospitals, use of a mobile intensive care service, and centralisation of care in a specialist unit.

More than standards and regulations are needed to provide safe and effective devices

Medical devices that met standards have been recalled. Quality systems that were said by internal audits to be in compliance with FDA regulations or ISO quality standards received serious questions after external auditing. Devices meeting standards or produced by quality systems felt to be in compliance have put patients at risk by failing at critical moments. Something more than just meeting standards and regulations is needed to provide safe and effective medical devices.

Dysfunction of endothelial protein C activation in severe meningococcal sepsis

BACKGROUND

Impairment of the protein C anticoagulation pathway is critical to the thrombosis associated with sepsis and to the development of purpura fulminans in meningococcemia. We studied the expression of thrombomodulin and the endothelial protein C receptor in the dermal microvasculature of children with severe meningococcemia and purpuric or petechial lesions.

METHODS

We assessed the integrity of the endothelium and the expression of thrombomodulin and the endothelial protein C receptor in biopsy specimens of purpuric lesions from 21 children with meningococcal sepsis (median age, 41 months), as compared with control skin-biopsy specimens.

RESULTS

The expression of endothelial thrombomodulin and of the endothelial protein C receptor was lower in the patients with meningococcal sepsis than in the controls, both in vessels with thrombosis and in vessels without thrombosis. On electron microscopical examination, the endothelial cells were generally intact in both thrombosed and nonthrombosed vessels. Plasma thrombomodulin levels in the children with meningococcal sepsis (median, 6.4 ng per liter) were higher than those in the controls (median, 3.6 ng per liter; P=0.002). Plasma levels, protein C antigen, protein S antigen, and antithrombin antigen were lower than those in the controls. In two patients treated with unactivated protein C concentrate, activated protein C was undetectable at the time of admission, and plasma levels remained low.

CONCLUSIONS

In severe meningococcal sepsis, protein C activation is impaired, a finding consistent with down-regulation of the endothelial thrombomodulin-endothelial protein C receptor pathway.

Antibacterial activity of black myrobalan (Terminalia chebula Retz) against Helicobacter pylori

The effect of ether, alcoholic and water extracts of black myrobalan (Teminalia chebula Retz) on Helicobactor pylori were examined using an agar diffusion method on Columbia Agar. Water extracts of black myrobalan showed significant antibacterial activity and had a minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC) of 125 and 150 mg/l, respectively. The extract was active after autoclaving for 30 min at 121 degrees C. Plant powder (incorporated in agar) gave higher MIC and MBC values (150 and 175 mg/l, respectively). Water extracts of the black myrobalan at a concentration of 1-2.5 mg/ml inhibited urease activity of H. pylori. The results show that black myrobalan extracts contain a heat stable agent(s) with possible therapeutic potential. Other bacterial species were also inhibited by black myrobalan water extracts.

Bactericidal/permeability-increasing protein--lessons learned from the phase III, randomized, clinical trial of rBPI21 for adjunctive treatment of children with severe meningococcemia

OBJECTIVES

To review the scientific rationale for the clinical use of recombinant bactericidal permeability-increasing protein (rBPI21) and to discuss the results, implications, and lessons learned during the clinical development of rBPI21 for adjunctive treatment of children with severe meningococcemia.

DATA SOURCES

The published medical literature.

STUDY SELECTION

Of the phase I/II and phase III trials in humans, preclinical experimental studies were selected. Data from these sources are presented in the context of the authors' experiences as principal investigators in the phase I/II and/or phase III clinical trials.

DATA EXTRACTION AND DATA SYNTHESIS

Bactericidal permeability-increasing protein and N-terminal fragments of bactericidal permeability-increasing protein, such as rBPI21, bind and neutralize endotoxin and are potently bactericidal against both smooth and rough forms of Gram-negative bacteria, including Neisseria meningitidis. Based on these properties and compelling preclinical data indicating that administration of rBPI21 reduced mortality in several models of sepsis, we initiated clinical trials by using rBPI21 as adjunctive therapy for children with severe meningococcemia. Data from the phase III, randomized, placebo-controlled trial indicate that rBPI21 reduces clinically significant morbidities and improves the functional outcome of children with severe meningococcemia. No statistically significant benefit in mortality was demonstrated; however, because of the rare incidence of disease and the rapidity of death in this study, the trial was substantially underpowered to detect a statistically significant mortality advantage. Before the completion of the trial, the probability that the study might have been underpowered to detect a significant reduction in mortality was recognized. An attempt at selecting a previously unvalidated composite end point to increase the meaningful event rate for the primary end point proved unsuccessful. Significant improvements were seen in other prospectively defined outcome variables that suggest an overall substantial benefit of therapy with rBPI21 in children with severe meningococcemia.

CONCLUSIONS

As the largest therapeutic trial conducted in pediatric critical care, the phase III trial of rBPI21 demonstrates important principles that can influence the design of future trials targeting rare, life-threatening diseases.

Evaluation and management of headache in the emergency department

In the ED, correct diagnosis is the necessary foundation on which specific therapy is based. There is no substitute for obtaining a thorough history and examining the patient competently. Patients with a past history of primary headaches, such as migraine, also may be afflicted with (new) secondary headaches. Although efficiency is desirable from the perspective of ED management, a thoughtful approach complemented by the judicious selection of tests is compatible with that goal as well as achieving the desired outcome of accurate diagnosis and relief of pain. Arrangements for long-term follow-up are important.

Coagulation in severe sepsis: a central role for thrombomodulin and activated protein C

OBJECTIVES

To review the mechanisms that cause coagulation abnormalities in sepsis, focusing on the interaction between the vascular endothelium and the circulating coagulation factors, particularly the role of the protein C pathway and thrombomodulin.

DATA SOURCES/STUDY SELECTION

Published research abstracts and review articles on the experimental and clinical investigation of the pathophysiology of disseminated intravascular coagulation in sepsis.

DATA EXTRACTION AND SYNTHESIS

The data provide increasing evidence that the coagulopathy seen in sepsis is a result of a complex imbalance of pro- and anticoagulant pathways. Whereas previous research has largely studied events in the plasma, it is now apparent that reactions on cell surfaces such as the vascular endothelium are important in the control of the regulatory pathways.

CONCLUSIONS

The plasma components of the protein C pathway are down-regulated in sepsis. Decreased thrombomodulin expression may cause defective function of the endothelial component of this pathway in septic patients. Treatments must be designed to overcome any functional defect.

Mastering the value chain. An interview with Mark Levin of Millennium Pharmaceuticals. Interview by David Champion

As today's business leaders are all too aware, a new scientific or technological break-through can quickly transform an industry's competitive landscape. The upheaval is often traumatic for the companies involved, forcing them to rethink their strategies and redefine their boundaries. But an industry in flux also creates vast opportunities. To seize them, companies must see how the current upheavals will affect the future distribution of profits--and then reinvent themselves to capitalize on the new sources of value. In this interview with HBR senior editor David Champion, Mark Levin, the founder and CEO of Millennium Pharmaceuticals, describes his vision of the future of the pharmaceutical industry in the wake of the genetics revolution and new technologies that have altered the economics of drug development. No company, he argues, will create serious long-term value by staying in just one or two stages of the value of chain. That's why Millennium, which started out doing basis research into genes and proteins and selling its findings to pharmaceutical giants, has moved downstream - toward the patients who actually use and pay for the drugs. He explains why the research end has become less lucrative than the more mechanical tasks of identifying, testing, and manufacturing molecules. Levin talks about the changes Millennium has undergone since its inception in 1993-from 30 workers to more than 1,000, and from one end of the value chain to the other. He discusses the company's cultural transformations as well as the partnerships and acquisitions that have helped millennium become involved in every stage of the chain-from gene to patient. Levin's vigorous approach to balancing long-term strategy with short-term tactics offers important lessons to any executive facing an industry upheaval.

Gaucher disease: Genetics, diagnosis and management

Gaucher disease is a storage disorder with varied manifestations. As the first storage disorder for which treatment is available, it is of considerable clinical and scientific importance. We review the history, clinical syndromes, molecular genetics and manifestations as well as modern diagnosis and therapy of the adult non-neuronopathic variant of Gaucher disease. (c) 2001 Prous Science. All rights reserved.

Meeting report of the American Society of Preventive Oncology

The American Society of Preventive Oncology sponsored its Silver Anniversary Meeting on March 11 and 12 in New York. This 25th annual meeting focused on cancer genomics, behavioral intervention strategies in cancer prevention and intervention, the methodologies of studying the role of physical activity in risk reduction as well as legislative and public health issues. This report will focus on the recent advances in risk identification, cancer genetics and interventional strategies. (c) 2001 Prous Science. All rights reserved.

ENT endoscopic surgical training simulator

This paper describes work in progress on the design and development of a prototype simulator for minimally invasive otolaryngology surgical training. The anatomy of the paranasal sinuses is geometrically complex and dangerously close to the brain and orbits, making this procedure challenging to practice and difficult to learn. We discuss the potential role of computer simulation to enhance and accelerate acquisition of surgical skills. The design goals of the prototype include high-fidelity simulation of the endoscopic imagery and haptic cues of surgical palpation. The prototype enables endoscopic navigation and limited interactive tissue manipulation and dissection tasks on a virtual patient using realistic replicas of surgical tools. We present an overview of the system architecture with a discussion of the technological challenges, design issues and current status of the efforts.

Tissue factor pathway inhibitor (TFPI) levels in the plasma and urine of children with meningococcal disease

Tissue factor pathway inhibitor (TFPI) is a potent inhibitor of the TF-dependent coagulation system. In meningococcal disease, up-regulation of tissue factor expression on blood monocytes and possibly on endothelial cells has the potential to trigger the activation of the TF-dependent pathway of coagulation. Intravascular coagulation is considered to be a major pathogenic factor in meningococcal disease. We postulated that imbalance between TF expression and TFPI concentration might lead to uncontrolled coagulation in meningococcal disease. The aim of this study was to assess the levels of total TFPI in the plasma of patients with meningococcal disease and assess whether increased leaking of the TFPI was occurring. TFPI antigen levels and activity were measured in the plasma of 54 patients with meningococcal disease, and 13 healthy control children. TFPI antigen level were also determined in the urines of 14 of the 54 and 9 healthy control children. Plasma TFPI activity was reduced in the meningococcal diseased patients (mean of 0.503 +/- 0.341 U/ml; control, 1.010 +/- 0.199 U/ml: p <0.0001), as was the TFPI antigen levels (mean of 54.85 +/- 35.05 ng/ml; Control, 94.51 +/- 11.44 ng/ml; p <0.0001). In contrast, TFPI antigen levels were increased in the urine of these patients when compared to the levels found in the urine of the healthy control children (mean of 12.96 +/- 5.392 ng/mmol creatinine; Control, 0.239 +/- 0.191 ng/mmol creatinine; p <0.035). A lack of correlation between TFPI-activity and TFPI-antigen plasma levels was observed (r = 0.002, p = 0.85). This data is consistent with the hypothesis that in meningococcal disease there is increased inactivation of plasma TFPI by the up regulation of tissue factor expression but in addition increased clearance of TFPI in urine is occurring.

Evaluation of new treatments for meningococcal disease

It is recognized that improvement in the practice of clinical medicine, including confirmation of the safety and efficacy of some current interventions, depends greatly on the pursuit of appropriate research. It therefore follows that improved clinical care of children depends on their participation in pediatric research. Furthermore, in the absence of relevant research, harm to children may result. Thus formal studies of therapeutic modalities in children is seen as a moral imperative to ensure that children have equal and safe access to existing and new agents (1).

Production of low-avidity antibody by infants after infection with serogroup B meningococci

Experimental serogroup B meningococcal vaccines have induced only poor immune responses and have had little protective efficacy in children younger than 1 year of age. We used ELISA with potassium thiocyanate to compare the average avidity of antibody produced by infants with that of children older than 10 years after systemic disease. Infants produced specific antibody of lower average avidity than older children--a finding that correlates with absence of serum bactericidal activity in the serum samples of the same infants.

Inherited predisposition to mycobacterial infection: historical considerations

Although one third of the world's population is estimated to be infected with Mycobacterium tuberculosis, only one tenth of infected individuals develop clinical disease. There is substantial epidemiological evidence that host genetic factors are important determinants of susceptibility to mycobacterial disease. This paper gives a historical context to the recent exciting advances in the field which have led to the identification of a number of human mycobacterial susceptibility genes.

Intimal hyperplasia recurs after removal of PDGF-AB and -BB inhibition in the rat carotid artery injury model

Several antagonists specific for platelet-derived growth factor (PDGF) or its receptors have recently been developed and shown to inhibit intimal hyperplasia formation in various animal models, but data investigating the durability of this intervention is limited. The present study was designed to investigate the potency of PDGF B-chain aptamer, a novel type of PDGF-AB and -BB antagonist, in the rat carotid model and to characterize intermediate-term effects on lesion formation. One hundred thirty-four animals were randomized to aptamer treatment or placebo. Daily treatment with the antagonist resulted in a 50% reduction in lesion size at 2 weeks (P<0.001). The beneficial effect involved increased apoptosis and possibly an interference with smooth muscle cell migration. Discontinuing administration 1 week earlier did not give any significant benefit compared with phosphate-buffered saline-treated controls. When the antagonist was administered for 2 weeks and the vessels analyzed 6 weeks later, the beneficial effect was lost and the treated lesions had a higher intima-media and area-cell ratio compared with the treated lesions in the 2-week-endpoint study. Our findings confirm a role of PDGF B-chain in intimal hyperplasia, but the successful use of PDGF antagonists may require either prolonged treatment or combination therapy with other agents.

Recombinant bactericidal/permeability-increasing protein (rBPI21) as adjunctive treatment for children with severe meningococcal sepsis: a randomised trial. rBPI21 Meningococcal Sepsis Study Group

BACKGROUND

Endotoxin is a primary trigger of the inflammatory processes that lead to shock, multiorgan failure, and purpura fulminans in meningococcal sepsis. Bactericidal/permeability-increasing protein (BPI) is a natural protein, stored within the neutrophil granules, that binds to and neutralises the effects of endotoxin in vitro, in laboratory animals, and in humans. To establish whether a recombinant 21-kDa modified fragment of human BPI (rBPI21), containing the active antimicrobial and endotoxin-neutralising moiety, would decrease death and long-term disability from meningococcal sepsis, we did a randomised, double-blind, placebo-controlled trial of rBPI21 in children with severe meningococcal sepsis.

METHODS

We enrolled children (2 weeks to 18 years of age) presenting to 22 centres in the UK and the USA with a clinical picture suggestive of meningococcal sepsis, and with evidence of severe disease. Children were randomly assigned rBPI21 (2 mg/kg over 30 min followed by 2 mg/kg over 24 h) or placebo (0.2 mg/mL human albumin solution) in addition to conventional medical therapy. Primary outcome variables were mortality, amputations, and change in paediatric overall performance category (POPC) from before illness to day 60. Analysis was by intention to treat.

FINDINGS

Of 1287 patients screened, 892 were excluded, including 57 patients who died or who met criteria for imminent death before receiving the study drug. 190 patients received rBPI21, and 203 placebo. 34 (8.7%) of 393 patients died during the study: 14 (7.4%) in the rBPI21 group and 20 (9.9%) in the placebo group (odds ratio 1.31 [95% CI 0.62-2.74], p=0.48). Compared with patients randomised to placebo, fewer patients treated with rBPI21 had multiple severe amputations (six of 190 [3.2%] vs 15 of 203 [7.4%], odds ratio 2.47 [0.94-6.51], p=0.067), and more had a functional outcome similar to that before illness (as measured by the POPC scale) at day 60 (136 of 176 [77.3%] vs 126 of 190 [66.3%], p=0.019).

INTERPRETATION

Because most deaths occurred in the interval between identification of patients and study drug administration, the mortality rate in the placebo group was substantially lower than predicted. The trial was therefore underpowered to detect significant differences in mortality. However, patients receiving rBPI21 had a trend towards improved outcome in all primary outcome variables. Given the excellent severity match between placebo and rBPI21 groups at study entry, the results overall indicate that rBPI21 is beneficial in decreasing complications of meningococcal disease.

Expression of connexin 30 in Xenopus embryos and its involvement in hatching gland function

Connexins are a family of proteins that assemble to form gap junction channels. Cell-cell communication through gap junctions mediates many important events in embryogenesis, including limb patterning, lens physiology, neuronal function, left-right asymmetry, and secretion from gland tissue. We studied the expression of connexin 30 (Cx30) in the Xenopus embryo and find that it is expressed in the developing hatching gland and pronephros. To determine whether its expression plays a functional role in the activity of the hatching gland, we exposed pre-hatching embryos to drugs that block gap junctional communication. This resulted in a continuation of normal growth and development but specifically abolished hatching. The treatment did not affect Cx30 or Xenopus hatching enzyme transcription, suggesting a post-transcriptional effect on Cx30 gap junctions. We conclude that junctional communication, possibly mediated by Cx30, is involved in secretion of hatching enzyme in Xenopus.

Evaluation of human antimycobacterial immunity using recombinant reporter mycobacteria

A novel in vitro whole blood model was developed to study human antimycobacterial immunity. Recombinant reporter mycobacteria were used to enumerate the bacteria, and interactions between host immune cells and mycobacteria were studied using whole blood rather than cell fractions. The ability of healthy tuberculin-positive and tuberculin-negative individuals to restrict mycobacterial growth was compared. Growth of luminescent mycobacteria was significantly lower in blood samples of tuberculin-positive individuals than in blood samples of tuberculin-negative individuals (P=.005). Restricted mycobacterial growth was associated with significantly higher production of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma (P=.01 and.004, respectively). Inhibition of the TNF-alpha and IFN-gamma response pathways by neutralizing monoclonal antibodies increased mycobacterial growth in whole blood. This model is the first functional assay in which individual variations in cell-mediated immunity are shown to correlate with differences in ability to control mycobacterial growth. It provides a new tool for studying human mycobactericidal mechanisms and, potentially, for the evaluation of improved vaccines.

Case reports: headache caused by a spinal cord stimulator in the upper cervical spine

We report persistent headaches developing in a patient subsequent to the placement of a spinal cord stimulator in the upper cervical spine. These persistent headaches responded to dihydroergotamine and sumatriptan. Headaches ceased upon repositioning of the stimulator lower in the cervical spine. We postulate an effect of the device on the trigeminovascular system via the nucleus caudalis trigeminalis and/or spinal trigeminal tract.

Acute oliguric renal failure associated with unilateral renal embolism: a successful treatment with iloprost

A 66-year-old woman presented with acute-onset rapid atrial fibrillation and right upper quadrant pain which had appeared 24 h prior to admission. The patient also manifested acute oliguric renal failure (serum creatinine 6.9 mg/dl). Selective renal angiography revealed total occlusion of the right renal artery with normal visualization of the left kidney vasculature. The patient was treated with intra-arterial urokinase and intravenous heparin, with no response. Intravenous administration of the prostacyclin analogue, iloprost, resulted in rapid resolution (within hours) of the oliguric acute renal failure, in spite of the continuing presence of a nonfunctioning right kidney. We conclude that the etiology of the acute renal insult in this patient is probably related to unilateral renal arterial embolization accompanied by arterial spasm of the unaffected kidney. The contralateral vasospasm can be reversed by iloprost, which then leads to a rapid recovery from acute renal failure. We are unaware of prior reports documenting the beneficial effect of iloprost in a clinical setting as described here.

Management and prevention of meningococcal disease

While many other illnesses affecting children have been contained or even eliminated, meningococcal disease has become a leading infectious cause of death. The major management challenge may be increased intracranial pressure or toxic shock, depending on whether meningitis or septicemia predominates. A new protein-conjugated group C vaccine is expected to reduce deaths by as much as 40%.

A myocardial cytotoxic process is involved in the cardiac dysfunction of meningococcal septic shock

OBJECTIVE

Myocardial dysfunction is a characteristic component of meningococcal septic shock and contributes to the persisting high mortality from the disease. Specific treatment of the myocardial failure has been hampered by the lack of understanding of its pathophysiology. We were interested to determine whether myocardial cell death was occurring in the presence of meningococcal septicemia and whether it correlated with the degree of left ventricular dysfunction and disease severity. We therefore investigated the release of cardiac troponin I (cTnI), a sensitive and specific marker of myocardial cell death, and related this to the severity of disease and cardiac dysfunction.

DESIGN

Prospective study

SETTING

Pediatric intensive care unit

SUBJECTS

Patients admitted to the pediatric intensive care unit with a diagnosis of meningococcal septicemia.

INTERVENTIONS

Serum concentrations of cTnI were determined at admission to intensive care in 101 children with meningococcal septicemia and serially in 37 children. Changes in cTnI were related to disease severity as measured by the Pediatric Risk of Mortality score and two markers of cardiac dysfunction.

MEASUREMENTS AND MAIN RESULTS

Serum concentrations of cTnI were elevated above the range for healthy children in 24% of children with meningococcal septicemia at admission and in 62% of patients within 48 hrs. The peak concentrations occurred between 12 and 36 hrs after admission. There were significant correlations between cTnI levels and disease severity and between cTnI levels and the degree of myocardial depression measured by quantitative transthoracic echocardiography and peak inotrope requirements.

CONCLUSIONS

The elevated serum concentrations of cTnI indicate that myocardial cell death is occurring in meningococcal septicemia. The relationship between cTnI and markers of myocardial function suggest that the cell death may have a role in the pathogenesis of myocardial dysfunction in meningococcal septicemia. Elucidation of the mechanism responsible for myocardial injury may lead to the development of therapeutic interventions to prevent or limit this cardiac damage.

Increased excretion of urinary glycosaminoglycans in meningococcal septicemia and their relationship to proteinuria

OBJECTIVES

Meningococcal septic shock is a devastating illness associated with an increase in vascular permeability leading to hypovolemia and accumulation of plasma proteins and fluid in tissues. The capillary leak syndrome is often associated with widespread thrombosis in the skin, limbs, and digits. We postulated that the increase in vascular permeability and the intravascular thrombosis might be caused by an inflammation-induced loss of endothelial and basement membrane glycosaminoglycans (GAGs), which play a role in the permeability and thromboresistant properties of the microvasculature.

DESIGN

Prospective, single-center observational study.

SETTING

University-affiliated meningococcal research unit and pediatric intensive care unit.

PATIENTS

Eighteen children requiring intensive care for meningococcal sepsis, 18 children with steroid-responsive nephrotic syndrome, and 18 healthy control children.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum concentrations and urine excretion of glycosaminoglycans were measured and related to changes in glomerular permeability to plasma proteins. The size-distribution and nature of glycosaminoglycans were defined by Polyacrylamide Gel Electrophoresis and specific enzyme digestion. Urinary excretion of heparan sulfate, chondroitin-4-sulfate, and chondroitin-6-sulfate were significantly increased in meningococcal disease (MD) relative to healthy controls and children with steroid-responsive nephrotic syndrome. The urinary GAGs in MD were of similar size to those in controls when analyzed after pronase digestion. However, analysis of proteoglycan size before proteolytic digestion showed the urinary GAGs in MD were of lower molecular weight and unattached to proteins. The fractional excretion of albumin and immunoglobulin G in MD increased with severity of disease. Patients with severe or fatal MD had albumin clearances overlapping those seen in steroid-responsive nephrotic syndrome. There was a significant correlation between proteinuria in MD and urinary excretion of heparan sulfate (r2 = 0.611, p < .0001), chondroitin-4-sulfate (r2 = 0.721, p < .0001), and chondroitin-6-sulfate (r2 = 0.395, p < .0001).

CONCLUSIONS

The capillary leak in meningococcal disease is associated with increased plasma and urine concentrations of GAGs, which may be proteolytically cleaved from endothelial and basement membrane sites. The correlation between the severity of protein leakage and the urine excretion of GAGs suggests that loss of GAGs may be causally related to the increase in permeability to proteins.

Jewish bioethics?

"Jewish Bioethics" as currently formulated has been criticized as being of parochial concern, drawing on obscure methodology, employing an authoritarian (and, to the modern mind, unintelligible) method of discourse and as being of little relevance to the wider community. We analyze Jewish bioethics in terms of rule and principle theory and demonstrate that it is based on rational consideration and reproducible reasoning. This approach allows methodological and terminological translation into a Western method of discourse that, in turn, has much to contribute to clarifying underlying principles and methods of application of modern bioethics.

Evolutionary conservation of mechanisms upstream of asymmetric Nodal expression: reconciling chick and Xenopus

Recent experiments have suggested a pathway of genes that regulate left-right asymmetry in vertebrate embryogenesis. The most downstream member of this cascade is nodal (XNR-1 in frogs), which is expressed in the left-side lateral mesoderm. Previous work in the chick [Levin, 1998] suggests that an inductive interaction by Shh (Sonic hedgehog) present at the midline was needed for the left-sided expression of nodal, which by default would not be expressed. Interestingly, it has been reported [Lohr et al., 1997] that in Xenopus, right-side mesoderm that is explanted at st. 15 and allowed to develop in culture, goes on to express nodal, suggesting that lateral mesoderm expresses this gene by default and that a repression of nodal by the midline is needed to achieve asymmetry. Such a contradiction raises interesting questions about the degree of conservation of the mechanisms upstream of nodal asymmetry and, in general, about the differences in the LR pathway among species. Thus we examined this issue directly. We show that in the chick, as in the frog, explanted mesoderm from both sides does, indeed, go on to express nodal, including both the medial and lateral expression domains. Ectopic nodal expression in the medial domain on the right side is not sufficient to induce an ectopic lateral domain. We also show that explanted lateral tissue regenerates node/notochord structures exhibiting Shh expression. Furthermore, we show that Xenopus explants done at st. 15 also regenerate notochord by the stage at which XNR-1 would be expressed. Thus explants are not isolated from the influence of the midline. In contrast to the midline repressor model previously suggested [Lohr et al., 1997] to explain the presence of nodal expression in explants, we propose that the expression is due to induction by signals secreted by regenerating node and notochord tissue (Shh in the chick). Thus our results are consistent with Shh being necessary for nodal induction in both species, and we provide an explanation for both sets of data in terms of a single conserved mechanism upstream of nodal expression.

Applied DC magnetic fields cause alterations in the time of cell divisions and developmental abnormalities in early sea urchin embryos

Most work on magnetic field effects focuses on AC fields. The present study demonstrates that exposure to medium-strength (10 mT-0.1 T) static magnetic fields can alter the early embryonic development of two species of sea urchin embryos. Batches of fertilized eggs from two species of urchin were exposed to fields produced by permanent magnets. Samples of the continuous cultures were scored for the timing of the first two cell divisions, time of hatching, and incidence of exogastrulation. It was found that static fields delay the onset of mitosis in both species by an amount dependent on the exposure timing relative to fertilization. The exposure time that caused the maximum effect differed between the two species. Thirty millitesla fields, but not 15 mT fields, caused an eightfold increase in the incidence of exogastrulation in Lytechinus pictus, whereas neither of these fields produced exogastrulation in Strongylocentrotus purpuratus.

Disseminated intravascular coagulation and purpura fulminans secondary to infection

Infection is one of the commonest causes of disseminated intravascular coagulation (DIC). DIC is a complex disorder that results from an imbalance of the pro- and anticoagulant regulatory pathways. This chapter will explain the cellular and molecular basis of the disorder and consider the rationale behind current and experimental treatment strategies.