Avoidable deficiencies in the delivery of health care to children with meningococcal disease

OBJECTIVES

It is apparent that delays and inadequate or inappropriate management occur frequently and may contribute to the continued high mortality seen in meningococcal disease. An attempt has been made to define the major sources of delay or inappropriate treatment.

METHODS

A prospective, descriptive study of children with meningococcal disease referred to a tertiary centre paediatric intensive care and infectious disease unit. Definitions of optimal care were established at three stages: parental; general practitioner (GP)/accident and emergency (A&E) department; and hospital. Duration of symptoms and management were recorded from direct questioning of parents and carers, and from hospital records.

RESULTS

54 consecutive children with meningococcal disease were recruited to the study. Delayed parental recognition occurred in 16 children. GPs correctly diagnosed 19 of 35 children. Delay of 2.5-21 hours occurred in those who were incorrectly diagnosed. Two of 15 children who presented to the A&E department with specific features were incorrectly diagnosed. Hospital treatment was suboptimal in 71%. Shock was not recognised or treated in 50%, 20% of children had unnecessary lumbar punctures. Time from illness onset to treatment was longer in fatal disease (median 18.3, range 8-24 hours), compared with survivors (median 12, range 2-48 hours; p < 0.01, Mann-Whitney U test).

CONCLUSION

Suboptimal treatment in meningococcal disease is due to failure of parents, GPs, and hospital doctors to recognise specific features of the illness. Improvement by public education and better training of clinicians in recognition, resuscitation, and stabilisation of seriously ill children.

Review and consideration of coagulopathies

Blood components bring nutrients to the tissues, remove wastes, provide defenses against microorganisms and foreign bodies, and retain sufficient fluidity to keep the system functioning properly. Coagulation factors are also present in the blood as part of a sensitive system that stems the flow of blood from a wound and maintains homeostasis. These factors include anuclear platelets that originate from megakaryocytes in the bone marrow, as well as soluble factors in precursor form, and calcium ion. Faults in single or multiple parts of this system, which can be determined in the patient's history, may result in bleeding problems that may be clinically relevant. Clarification of coagulation defects requires cooperation with a hematologist before medication that affects the coagulation system is prescribed or before any procedures that may result in bleeding are undertaken.

Blood pressure and diurnal variation in sodium, potassium, and water excretion

The objective of this study was to examine associations of blood pressure (BP) with ratios of overnight to 24-h urinary excretion of sodium, potassium, and water. Each of 125 men 27-64 years of age, not taking diuretics, had BP measured during the day on a Monday. Beginning Monday evening, each participant provided three carefully timed 24-h urine collections, divided into daytime and overnight (bedtime to awakening) specimens. Proportion of total 24-h excretion of sodium, potassium, and water in the overnight specimen, standardised for creatinine excretion, was determined for each 24-h period. Associations of systolic and diastolic BP (SBP/DBP) with these proportions were examined with control for age, body mass index, alcohol intake, and heart rate. Mean BP was 116/71 mm Hg; 15 men were on non-diuretic anti-hypertensive therapy. Mean 24-h urinary excretion was 168 mmol for sodium, 68 mmol for potassium, and 16 mmol for creatinine. Mean overnight to 24-h proportions averaged over the 3 days were 30.7% for sodium, 22.0% for potassium, 32.1% for urinary volume, and 33.2% for creatinine. Partial correlations of SBP and DBP with the 3-day averages were 0.257 (P < 0.01) and 0.210 (P < 0.05) for sodium; 0.223 (P < 0.05) and 0.222 (P < 0.05) for potassium; 0.127 and 0.091 for urinary volume; and -0.033 and 0.014 for creatinine. Correlations for sodium proportions were larger for the first 24-h period, compared to the second or third 24-h period. These results indicate that higher BP was associated with a relatively greater proportion of sodium and potassium excretion at night. Further work is needed to clarify temporal sequence, ie, whether a relatively greater sodium and potassium excretion at night is a risk factor for higher BP (eg, via renal mechanisms), or whether higher BP results in relatively greater sodium and potassium excretion at night, or both.

The roles of activin and follistatin signaling in chick gastrulation

Activin, a TGF-beta family member, and follistatin, an activin antagonist, encode signaling proteins which have been implicated in fundamental events in early vertebrate embryogenesis, such as mesoderm and neural tissue induction, and axial patterning. In this study I examine the roles of activin and follistatin in gastrulation in the chick. Activin betaB is found to be expressed at the base of the primitive streak prior to its formation, consistent with a role in streak induction. Follistatin has a more complex and dynamic expression in Hensen's node, and exhibits a left-right (LR) asymmetry. Antagonizing endogenous activin by ectopic application of follistatin protein causes the partial dissolution of the primitive streak and node, both morphologically and as assayed by loss of expression of molecular markers. This suggests that activin is necessary for the maintenance of streak morphology, and that follistatin may be involved in termination of the anterior progress of streak growth or in suppression of supernumerary streaks. Cell ingression through the node following follistatin application is normal, suggesting that it does not depend on the pit-like morphology of the wild-type node. Finally, follistatin temporally extends the asymmetric pattern of expression of HNF3-beta, this, as well as the stronger right-sided expression of follistatin, suggests a possible role in LR patterning.

Left-right asymmetry and the chick embryo

Left-right (LR) asymmetry provides a fascinating example of the patterning of a major body axis during embryonic development. The chick embryo was the first system in which a molecular basis for left-right patterning was characterized, revealing that molecules known to play a role in other aspects of embryogenesis likewise are involved in the establishment of left-right asymmetry. The chick has been instrumental in the identification of a pathway of genes which regulate the sidedness of major body organs, as well as providing a basis for understanding laterality disturbances in twins. This review summarizes the advances in LR asymmetry which have been made in the chick system within the context of laterality research in general.

Kawasaki disease thirty years on

This year marks the 30th anniversary of the first description of Kawasaki disease. The disease has emerged as an important cause of acquired heart disease in children. The cause of Kawasaki disease remains unknown and this presents many problems in the diagnosis and management of the disease. This paper reviews recent publications on the pathogenesis, diagnosis, and the short- and long-term management of Kawasaki disease.

Erythema migrans-like rash illness at a camp in North Carolina: a new tick-borne disease?

BACKGROUND

Borrelia burgdorferi, the causative agent of Lyme disease, has never been isolated from a patient thought to have acquired Lyme disease in any southeastern state.

OBJECTIVE

To investigate 14 cases of an erythema migrans (EM)-like rash illness that occurred during 2 summers at an outdoor camp in central North Carolina in an effort to determine the etiologic, epidemiological, and clinical aspects of this illness.

METHODS

Using active surveillance, we identified cases of clinically diagnosed EM in residents and staff of the camp. We collected clinical and demographic information; history of exposure to ticks; acute and convalescent serum antibodies to B. burgdorferi, Rickettsia rickettsii, and Ehrlichia chaffeensis; and cultures for spirochetes from biopsy specimens of skin lesions. Serum samples from a group of residents and staff who did not develop rashes were tested for the same antibodies. We speciated ticks removed from people and collected from vegetation.

RESULTS

We identified 14 cases of EM-like rash illness during the 2 summers. Of the 14 case-patients, 10 had associated mild systemic symptoms and 1 had documented fever. All 14 case-patients had removed attached ticks, and 8 remembered having removed a tick from the site where the rash developed a median of 12 days earlier (range, 2-21 days). One tick removed from the site where a rash later developed was identified as Amblyomma americanum, the Lone Star tick; 97% of ticks collected from vegetation and 95% of ticks removed from people were A. americanum. No spirochetes were isolated from skin biopsy specimens. Paired serum samples from 13 case-patients did not show diagnostic antibody responses to B. burgdorferi or other tick-borne pathogens.

CONCLUSIONS

This investigation suggests the existence of a new tick-associated rash illness. We suspect that the disease agent is carried by A. americanum ticks. In the southern United States, EM-like rash illness should no longer be considered definitive evidence of early Lyme disease.

A comparative analysis of integrating visual representations with haptic displays

As further advances in visual display technologies and force feedback devices are integrated in virtual systems, questions remain: What level of reality does the system provide to the user? Is the environment convincing enough to engage the user and to maximize transfer? Are the visual and haptic displays fully integrated to provide seamless operation in the simulated environment? Does the system provide not only the ability to navigate through a simulated environment, but also realistic interaction with instrumentation and structures? We report on our advances in developing a virtual simulation system for training in functional endoscopic sinus surgery (FESS). Specifically, we will present work on subject trials exploring the realism provided by integrated visual and haptic displays, and compare and contrast surface vs. volume representation for presenting realistic models of the anatomy for surgical interaction.

Partial interferon-gamma receptor 1 deficiency in a child with tuberculoid bacillus Calmette-Guérin infection and a sibling with clinical tuberculosis

Complete interferon-gamma receptor 1 (IFNgammaR1) deficiency has been identified previously as a cause of fatal bacillus Calmette-Guérin (BCG) infection with lepromatoid granulomas, and of disseminated nontuberculous mycobacterial (NTM) infection in children who had not been inoculated with BCG. We report here a kindred with partial IFNgammaR1 deficiency: one child afflicted by disseminated BCG infection with tuberculoid granulomas, and a sibling, who had not been inoculated previously with BCG, with clinical tuberculosis. Both responded to antimicrobials and are currently well without prophylactic therapy. Impaired response to IFN-gamma was documented in B cells by signal transducer and activator of transcription 1 nuclear translocation, in fibroblasts by cell surface HLA class II induction, and in monocytes by cell surface CD64 induction and TNF-alpha secretion. Whereas cells from healthy children responded to even low IFN-gamma concentrations (10 IU/ml), and cells from a child with complete IFNgammaR1 deficiency did not respond to even high IFN-gamma concentrations (10,000 IU/ml), cells from the two siblings did not respond to low or intermediate concentrations, yet responded to high IFN-gamma concentrations. A homozygous missense IFNgR1 mutation was identified, and its pathogenic role was ascertained by molecular complementation. Thus, whereas complete IFNgammaR1 deficiency in previously identified kindreds caused fatal lepromatoid BCG infection and disseminated NTM infection, partial IFNgammaR1 deficiency in this kindred caused curable tuberculoid BCG infection and clinical tuberculosis.

Digital ischemia and gangrene due to red blood cell aggregation induced by acquired dysfibrinogenemia

Digital gangrene was observed in a patient who had angiographic findings of digital arterial occlusion. The patient's blood showed a marked red blood cell aggregation with rouleaux formation in long chains, which could not be dispersed at shear rates up to 200 sec-1. Studies of the patient's blood revealed the presence of an abnormal fibrinogen capable of aggregating normal red blood cells. This fibrinogen was found by Raman spectroscopy to have an increased alpha-helical content, whereas the beta-sheet content was decreased. Defibrinogenation therapy with ancrod resulted in a dramatic symptomatic relief. The disappearance of the abnormal fibrinogen 6 months later and an absence of a family history indicate that this dysfibrinogenemia was acquired.

Two molecular models of initial left-right asymmetry generation

Left-right (LR) asymmetry is a fascinating problem in embryonic morphogenesis. Recently, a pathway of genes has been identified which is involved in LR patterning in vertebrates. Although this work characterizes the interactions of several asymmetrically-expressed genes, it is still entirely unclear how such asymmetric expression is set up in the first place. There are two promising molecular candidates which may play a role is such a process: the motor protein dynein, and the gap junction protein connexin-43 (Cx43). We present two models, significantly supported by previous findings, which hypothesize that (a) dynein asymmetrically localizes LR determinants in individual cells to establish cell-autonomous LR biasing, and (b) asymmetric activity of Cx43 gap junctions within key cells sets up electric potentials in multicellular fields, thus establishing large-scale LR asymmetry.

Left/right patterning signals and the independent regulation of different aspects of situs in the chick embryo

Recently, a pathway of genes which are part of a cascade regulating the side on which the heart forms during chick development was characterized (M. Levin et al., 1995, Cell 82, 1-20). Here we extend these previous studies, showing that manipulation of at least one member of the cascade, Sonic hedgehog (Shh), can affect the situs of embryonic rotation and of the gut, in addition to the heart. Bilateral expression of Shh, which is normally found exclusively on the left, does not result in left isomerism (a bilaterally symmetrical embryo having two left sides) nor in a complete situs inversus phenotype. Instead, misexpression of Shh on the right side of the node, which in turn leads to bilateral nodal expression, produces a heterotaxia-like condition, where different aspects of laterality are determined independently. Heart situs has previously been shown to be altered by ectopic Shh and activin. However, the most downstream gene identified in the LR pathway, nodal, had not been functionally linked to heart laterality. We show that ectopic (right-sided) nodal expression is able to affect heart situs, suggesting that the randomization of heart laterality observed in Shh and activin misexpression experiments is a result of changes in nodal expression and that nodal is likely to regulate heart situs endogenously. The first defined asymmetric signal in the left-right patterning pathway is Shh, which is initially expressed throughout Hensen's node but becomes restricted to the left side at stage 4(+). It has been hypothesized that the restriction of Shh expression may be due to repression by an upstream activin-like factor. The involvement of such an activin-like factor on the right side of Hensen's node was suggested because ectopic activin protein is able to repress Shh on the left side of the node, as well as to induce ectopic expression of a normally right-sided marker, the activin receptor cAct-RIIa. Here we provide further evidence in favor of this model. We find that a member of this family, Activin betaB, is indeed expressed asymmetrically, only on the right side of Hensen's node, at the correct time for it to be the endogenous asymmetric activin signal. Furthermore, we show that application of follistatin-loaded beads eliminates the asymmetry in Shh expression, consistent with an inhibition of an endogenous member of the activin-BMP superfamily. This combined with the previous data on exogenous activin supports the model that Activin betaB functions in the chick embryo to initiate Shh asymmetry. While these data extend our understanding of the early signals which establish left-right asymmetry, they leave unanswered the interesting question of how the bilateral symmetry of the embryo is initially broken to define a consistent left-right axis. Analysis of spontaneous chick twins suggests that, whatever the molecular mechanism, left-right patterning is unlikely to be due to a blastodermal prepattern but rather is initiated in a streak-autonomous manner.

Feeding density influences acquisition of Borrelia burgdorferi in larval Ixodes scapularis (Acari: Ixodidae)

The intensity of Borrelia burgdorferi transmission in nature is dependent upon the efficiency of acquisition of spirochetes by larval Ixodes scapularis Say (= I. dammini Spielman, Clifford, Piesman & Corwin). White-footed mice infected with B. burgdorferi were infested weekly for 5 consecutive weeks with 25 or 250 larval I. scapularis. Prevalence of infection in nymphs derived from larvae fed at high density (25.0-38.9%) was consistently higher than in nymphs derived from larvae fed at low density (6.7-23.5%). Spirochete prevalence in nymphal I. scapularis populations in nature may be influenced by larval population density.

Effect of aerosolization on culturability and viability of gram-negative bacteria

Estimations of the bacterial content of air can be more easily made now than a decade ago, with colony formation the method of choice for enumeration of airborne bacteria. However, plate counts are subject to error because bacteria exposed to the air may remain viable yet lose the ability to form colonies, i.e., they become viable but nonculturable. If airborne bacteria exhibit this phenomenon, colony formation data will significantly underestimate the bacterial populations in air samples. The objective of the study reported here was to determine the effect of aerosolization on viability and colony-forming ability of Serratia marcescens, Klebsiella planticola, and Cytophaga allerginae. A collision nebulizer was used to spray bacterial suspensions into an aerosol chamber, after which duplicate samples were collected in all-glass impingers over a 4-h period. Humidity was maintained at ca. 20 to 25%, and temperature was maintained at 20 to 22 degrees C for each of two replicate trials per microorganism. Viability was determined by using a modified direct viable count method, employing nalidixic acid or aztreonam and p-iodonitrotetrazolium violet (INT). Cells were stained with acridine orange and observed by epifluorescence microscopy to enumerate total and viable cells. Viable cells were defined as those elongating in the presence of antibiotic and/or reducing INT. CFU were determined by plating on tryptic soy agar and R2A agar. It was found that culture techniques did not provide an adequate description of the bacterial burdens of indoor air (i.e., less than 10% of the aerosolized bacteria were capable of forming visible colonies). It is concluded that total cell count procedures provide a better approximation of the number of bacterial cells in air and that procedures other than plate counting are needed to enumerate bacteria in aerosol samples, especially if the public health quality of indoor air is to be estimated.

Effect of ingested sodium bicarbonate on muscle force, fatigue, and recovery

The influence of acute ingestion of NaHCO3 on fatigue and recovery of teh quadriceps femoris muscle after exercise was studied in six healthy male subjects. A bicycle ergometer was used for exercising under three loading conditions: test A, load corresponding to maximal oxygen consumption; test B, load in test A + 17%; test C, load in test B but performed 1 h after acute ingestion of NaHCO3. Functional electrical stimulation (FES) was applied to provoke isometric contraction of the quadriceps femoris. The resulting knee torque was monitored during fatigue (2-min chronic FES) and recovery (10-s FES every 10 min, for 40 min). Quadriceps torques were higher in the presence of NaHCO3 (P < 0.05): with NaHCO3 the peak, residual, and recovery (after 40 min) normalized torques were, respectively, 0.68 +/- 0.05 (SD), 0.58 +/- 0.05, and 0.73 +/- 0.05; without NaHCO3 the values were 0.45 +/- 0.04, 0.30 +/- 0.06, and 0.63 +/- 0.06. The increased torques obtained after acute ingestion of NaHCO3 indicate the possible existence of improved nonoxidative glycolysis in isometric contraction, resulting in reduced fatigue and enhanced recovery.