Microscale Neuronal Activity Collectively Drives Chaotic and Inflexible Dynamics at the Macroscale in Seizures

Neuronal activity propagates through the network during seizures, engaging brain dynamics at multiple scales. Such propagating events can be described through the avalanches framework, which can relate spatiotemporal activity at the microscale with global network properties. Interestingly, propagating avalanches in healthy networks are indicative of critical dynamics, where the network is organised to a phase transition, which optimises certain computational properties. Some have hypothesised that the pathological brain dynamics of epileptic seizures are an emergent property of microscale neuronal networks collectively driving the brain away from criticality. Demonstrating this would provide a unifying mechanism linking microscale spatiotemporal activity with emergent brain dysfunction during seizures. Here, we investigated the effect of drug-induced seizures on critical avalanche dynamics, using in vivo whole-brain 2-photon imaging of GCaMP6s larval zebrafish (males and females) at single neuron resolution. We demonstrate that single neuron activity across the whole brain exhibits a loss of critical statistics during seizures, suggesting that microscale activity collectively drives macroscale dynamics away from criticality. We also construct spiking network models at the scale of the larval zebrafish brain, to demonstrate that only densely connected networks can drive brain-wide seizure dynamics away from criticality. Importantly, such dense networks also disrupt the optimal computational capacities of critical networks, leading to chaotic dynamics, impaired network response properties and sticky states, thus helping to explain functional impairments during seizures. This study bridges the gap between microscale neuronal activity and emergent macroscale dynamics and cognitive dysfunction during seizures.Significance StatementEpileptic seizures are debilitating and impair normal brain function. It is unclear how the coordinated behaviour of neurons collectively impairs brain function during seizures. To investigate this we perform fluorescence microscopy in larval zebrafish, which allows for the recording of whole-brain activity at single-neuron resolution. Using techniques from physics, we show that neuronal activity during seizures drives the brain away from criticality, a regime that enables both high and low activity states, into an inflexible regime that drives high activity states. Importantly, this change is caused by more connections in the network, which we show disrupts the ability of the brain to respond appropriately to its environment. Therefore, we identify key neuronal network mechanisms driving seizures and concurrent cognitive dysfunction.

Imaging epilepsy in larval zebrafish

Our understanding of the genetic aetiology of paediatric epilepsies has grown substantially over the last decade. However, in order to translate improved diagnostics to personalised treatments, there is an urgent need to link molecular pathophysiology in epilepsy to whole-brain dynamics in seizures. Zebrafish have emerged as a promising new animal model for epileptic seizure disorders, with particular relevance for genetic and developmental epilepsies. As a novel model organism for epilepsy research they combine key advantages: the small size of larval zebrafish allows high throughput in vivo experiments; the availability of advanced genetic tools allows targeted modification to model specific human genetic disorders (including genetic epilepsies) in a vertebrate system; and optical access to the entire central nervous system has provided the basis for advanced microscopy technologies to image structure and function in the intact larval zebrafish brain. There is a growing body of literature describing and characterising features of epileptic seizures and epilepsy in larval zebrafish. Recently genetically encoded calcium indicators have been used to investigate the neurobiological basis of these seizures with light microscopy. This approach offers a unique window into the multiscale dynamics of epileptic seizures, capturing both whole-brain dynamics and single-cell behaviour concurrently. At the same time, linking observations made using calcium imaging in the larval zebrafish brain back to an understanding of epileptic seizures largely derived from cortical electrophysiological recordings in human patients and mammalian animal models is non-trivial. In this review we briefly illustrate the state of the art of epilepsy research in zebrafish with particular focus on calcium imaging of epileptic seizures in the larval zebrafish. We illustrate the utility of a dynamic systems perspective on the epileptic brain for providing a principled approach to linking observations across species and identifying those features of brain dynamics that are most relevant to epilepsy. In the following section we survey the literature for imaging features associated with epilepsy and epileptic seizures and link these to observations made from humans and other more traditional animal models. We conclude by identifying the key challenges still facing epilepsy research in the larval zebrafish and indicate strategies for future research to address these and integrate more directly with the themes and questions that emerge from investigating epilepsy in other model systems and human patients.

A comparison of two nasal continuous positive airway pressure interfaces--a randomized crossover study

BACKGROUND

In spite of widespread use of nasal CPAP there are comparatively few studies to guide the choice of nasal prongs.

OBJECTIVES

To determine whether the Fisher & Paykel Healthcare (FPH) neonatal continuous positive airway pressure (CPAP) interface was effective in providing bubble CPAP when compared to the Hudson prong interface.

METHODS

The study was a randomized cross-over study of twenty newborn infants 500 g or more requiring CPAP for respiratory support at birth. Infants were randomized to either the Fisher & Paykel Healthcare or Hudson CPAP interface for twenty four hours. Crossover between interfaces occurred after subsequent twenty four hour periods. The primary outcome was the provision of desired CPAP pressures, defined as provision of CPAP within ± one cm H2O of set pressure.

RESULTS

The percentage time CPAP was within ± one cm H2O of set pressure was 66.5% for the Hudson and 71.8% for the FPH interface (p = 0.66). Oxygen saturations for the Hudson interface were in target range for a median of 97.8% of the time, and, with the FPH interface, for a median of 98.2% of the time (p = 0.76). Clinically significant differences in primary or secondary outcomes between the two groups were not detected.

CONCLUSIONS

The nasal CPAP interfaces studied were equally effective in achieving desired bubble CPAP pressures and target saturations.

Brain imaging: how stable are synaptic connections?

Cortical circuits can undergo experience-dependent remodeling, while retaining the capacity for long-term information storage. The stability of individual synaptic connections is fundamental to both processes, but poorly understood; two studies using new in vivo imaging techniques have finally shed some light on this important issue.

Recombinant erythropoietin and blood transfusion in selected preterm infants

OBJECTIVES

To comprehensively identify preterm infants likely to require blood transfusion and to investigate the effectiveness of recombinant erythropoietin in this high risk subgroup.

DESIGN

Double blind randomised controlled trial.

SETTING

Neonatal Intensive Care Unit, Middlemore Hospital, Auckland, New Zealand.

PATIENTS

Preterm infants < 33 weeks gestation and < 1700 g birth weight meeting specific criteria indicating a high possibility of requiring blood transfusion.

INTERVENTIONS

Predictors of blood transfusion were determined by analysis of preterm infants admitted to a neonatal intensive care unit over a two year period. Using the criteria developed, high risk infants entered the study and received erythropoietin or sham treatment until 34 weeks completed gestation. The sample size was calculated to detect a reduction of one blood transfusion per infant (significance level 5%, power 80%).

RESULTS

The selection criteria had a positive predictive value for transfusion of 91% and a negative predictive value of 94%. Mean birth weights and gestational ages were similar in the two groups. Absolute reticulocyte counts and haemoglobin values were higher in the group receiving erythropoietin. There was no significant difference in the number of blood transfusions received in the treatment and control groups. However, comparing transfusions given to < 1000 g infants after 30 days of age, there were significantly fewer transfusions in the erythropoietin group (mean (SD) 0.5 (0.7) in those receiving erythropoietin and 1.6 (1.1) in the controls). No adverse effects were noted.

CONCLUSIONS

The selection criteria for the study were highly predictive of subsequent transfusion. In the group receiving erythropoietin, a reduction in transfusion requirements was apparent only in the < 1000 g birthweight group after 1 month of age.

The extracellular ATP receptor, cP2Y(1), inhibits cartilage formation in micromass cultures of chick limb mesenchyme

We have investigated the function of the G protein-coupled receptor for extracellular ATP, chick P2Y(1) (cP2Y(1)) during development of the chick limb. cP2Y(1) is strongly expressed in undifferentiated limb mesenchyme cells but appears to be lost from cells as they differentiate, raising the possibility that the function of this receptor may be to inhibit cell differentiation. This pattern of expression was particularly striking surrounding areas of cartilage formation. We tested whether cP2Y(1) was able to regulate cartilage formation by using an in-vitro micromass model of chondrogenesis. Because limb cells in micromass culture lose expression of cP2Y(1), we have used a gain-of-function approach to demonstrate that cP2Y(1) expression can inhibit cartilage differentiation. We also demonstrate that early limb mesenchyme cells release ATP into the extracellular medium and have mechanisms to breakdown extracellular ATP. These results suggest that extracellular ATP, signaling through cP2Y(1), can modulate the differentiation of limb mesenchyme cells in vitro, and the expression pattern of cP2Y(1) suggests that this type of signaling could play a similar role in ovo.

A clinical comparison of radiant warmer and incubator care for preterm infants from birth to 1800 grams

OBJECTIVE

The objective of this study was to compare radiant warmer and incubator care for preterm infants from birth with respect to temperature control and weight gain.

METHODS

Sixty preterm infants <33 weeks' gestation were randomized at birth to radiant warmer or incubator care. The initial goal was to maintain abdominal temperature at 36.8 degrees C in both groups and axillary temperature at 36.8 to 37.3 degrees C; air servocontrol was used for incubator infants. Infants in both groups received added humidity for 5 days if their weight was <1000 g and for 3 days if they weighed between 1000 and 1249 g. During a 3-hour period on days 1 to 7, recordings of abdominal, forehead, and foot temperatures were obtained. The percentage of the recording time during which the abdominal temperature was in the target range of between 36 degrees C and 37.5 degrees C was determined as an indicator of temperature control. Weight gain from birth to 1800 g was compared. Secondary outcomes included fluid balance and clinical events.

RESULTS

There were 30 infants in each group; 48 were <1500 g (of whom 17 were <1000 g). There were no significant differences in birth weight, gestation, gender, or illness severity scores in the 2 groups. Significant differences in temperature control were noted on day 1. Although admission temperatures were similar, lower abdominal temperatures were noted in the first 2 hours of life in the incubator group (medians were 36.6 degrees C and 35.9 degrees C in the radiant warmer and incubator groups, respectively). Similarly, mean abdominal temperatures during the 3-hour recording on day 1 were lower in the incubator group, and infants in this group spent a significantly greater percentage of the recording time with temperatures outside the target range (17.3% compared with 0.88%). Other temperature recordings from the forehead and foot were not significantly different in the groups. Fluid intakes were higher for infants under radiant warmer on days 2, 3, and 4, and the difference amounted to a mean of 12.8 mL/kg/d. Maximum sodium levels in the first week were similar in the 2 groups. Mean weight gain was 17.4 g/kg/d for the radiant warmer group and 17.1 g/kg/d for the incubator group; days to regain birth weight and length of hospital stay were not significantly different. Greater numbers of infants in the radiant warmer group required phototherapy, and adverse events (which included death, necrotizing enterocolitis, chronic lung disease, grade 3 or 4 intraventricular hemorrhage, periventricular leukomalacia, or retinopathy requiring laser treatment) were less frequent in the radiant warmer group (1 infant compared with 8 in the incubator group; relative risk 0.1; 95% confidence intervals: 0.01-0.82).

CONCLUSIONS

This study has shown differences in abdominal temperatures on day 1 and outcome, although the latter finding should be viewed with caution because of the sample size. The results indicate benefits for the initial use of the radiant warmer after birth. Although fluid requirements were higher in the radiant warmer group for days 2 through 4, the increased fluid volumes were given without apparent adverse effect.

Whole-blood hemagglutination inhibition test for venereal disease research laboratory (VDRL) antibodies

Nontreponemal antibody tests such as the Venereal Disease Research Laboratory (VDRL) test are carried out on serum and widely used as screening tests for syphilis. The aim of the present study was to develop a screening test for syphilis making use of whole blood and VDRL liposomes. Antibody to human red blood cells was conjugated to VDRL liposomes and reacted with a diluted sample of patient whole blood. A total of 951 samples were tested by the new test and the VDRL tube test. All 49 VDRL samples positive by the VDRL test showed inhibition of hemagglutination in the whole-blood test (sensitivity, 100%). Of 902 samples with negative results by the VDRL test, 901 caused hemagglutination when tested with the liposomes (specificity, 99.9%). The hemagglutination inhibition method tests for syphilis in a simple one-step procedure in which whole blood is added to a tube containing liposomes. The new test has potential for point-of-care testing in developing countries.

Optimal Fungicide Management of Purple Spot of Asparagus and Impact on Yield

Purple spot disease of asparagus, caused by the fungus Stemphylium vesicarium, results in lesions on spears and ferns and defoliation of ferns. In two newly established commercial asparagus fields (cvs. Jersey Giant and Jersey Knight), chlorothalonil or mancozeb was applied every 7, 10, or 14 days or according to Tom-Cast with a threshold of 15 disease severity values, and not applied to the control. Tom-Cast prompted four sprays, resulting in a 60% reduction in the number of fungicide applications when compared with the 7-day-interval treatment. When disease pressure was severe, lesions on ferns were significantly less for both cultivars when fungicides were applied according to Tom-Cast or every 7 days compared with spray intervals of 10 or 14 days. Applying fungicides according to Tom-Cast or every 7 days resulted in an increased Jersey Giant fern stand compared with applying fungicides every 10 or 14 days. Unsprayed control plots yielded 77 to 83% (depending on cultivar) of those plots treated according to Tom-Cast using chlorothalonil. Significantly higher yields of Jersey Knight were obtained for chlorothalonil versus mancozeb. When mancozeb was used, Jersey Knight yield was significantly increased with a 7-day versus Tom-Cast application regime. Using chlorothalonil in a Tom-Cast program provided a benefit per hectare (BPH) of $1,005.24 (Jersey Knight) to $2,057.69 (Jersey Giant). In comparison, using mancozeb in a Tom-Cast program provided a BPH of -$484.27 (Jersey Knight) to $1,030.55 (Jersey Giant) over a 2-year period.

Expression of two ATP-gated ion channels, P2X5 and P2X6, in developing chick skeletal muscle

Physiological and pharmacological studies have shown that ATP has potent effects on developing chick skeletal muscle. These effects have previously been shown to be developmentally regulated, and the responses were characteristic of activation of the P2X ligand-gated ion-channel family of ATP receptors. Here, using immunohistochemistry, we describe the expression patterns of two members of the P2X receptor family, P2X5 and P2X6, during development of skeletal muscle in the chick embryo. These receptors were first expressed at early stages of skeletal muscle development, and expression disappeared immediately before the stage at which fusion of myoblasts to form myotubes occurs. P2X5 was also demonstrated in nerves supplying developing skeletal muscle, in some dorsal root ganglion cells, and in dorsal and ventral spinal cord. No expression of the other five members of the P2X family were demonstrated in developing skeletal muscle.

Selective expression of purinoceptor cP2Y1 suggests a role for nucleotide signalling in development of the chick embryo

Responses to extracellular nucleotides (e.g., ATP, ADP, etc.) have been demonstrated in a number of embryonic cell types suggesting they may be important signalling molecules during embryonic development. Here the authors describe for the first time the expression of a G-protein-coupled receptor for extracellular ATP, chick P2Y1 (cP2Y1), during embryonic development of the chick. During the first 10 days of embryonic development, cP2Y1 is expressed in a developmentally regulated manner in the limb buds, mesonephros, brain, somites, and facial primordia, suggesting that this receptor may have a role in the development of each of these systems.

Mechanical activity is necessary for the elimination of polyneuronal innervation of developing rat soleus muscles

During early development, rat soleus muscle fibres are innervated by several axons. Neuromuscular activity is involved in the elimination of all but one terminal, but it is not clear whether electrical or mechanical activity is important. Here, we reduced mechanical activity only, by interfering with excitation-contraction coupling. Muscles treated with dantrolene sodium at 9 days produced significantly less force at 13 days of age than normal muscles, and their sensitivity to ACh was greater than that of controls. The elimination of polyneuronal innervation occurs between days 9-12, but in muscles treated with dantrolene, the loss of synapses was slower. Thus, reducing mechanical activity by interfering with excitation-contraction coupling, (a) delays muscle development and (b) reduces the rate of elimination of polyneuronal innervation.

Anaemia of prematurity. Epidemiology, management and costs

Recombinant human erythropoietin (rHuEpo) has been increasingly used in preterm infants in the last 3 to 4 years. Recent studies have indicated a reduction in blood transfusion requirements in infants receiving rHuEpo. No significant adverse effects have emerged, apart from iron deficiency (if iron supplementation is inadequate), and the risk of transfusion-related infection is decreased. Nevertheless, rHuEpo is relatively expensive (a 6-week course costs approximately the same as 2 blood transfusions), so its use requires careful consideration; it is logical to target rHuEpo therapy to those babies who are most likely to be transfused. Using this strategy, 1 study involving stable growing preterm infants has shown that direct costs of blood transfusion and rHuEpo were similar, and the use of rHuEpo was recommended. In addition, use of high-dosage rHuEpo early in the course of management on the neonatal intensive care unit has been shown to reduce direct treatment costs in ill preterm infants. Further studies will continue to identify infants who are likely to benefit from rHuEpo therapy and to define its cost effectiveness in more detail.

Symptomatic HIV infection in infancy--clinical and laboratory markers of infection

OBJECTIVE

To investigate the usefulness of immunological tests in the diagnosis of HIV infection in young symptomatic children (< 15 months of age).

DESIGN

Tests were evaluated in HIV-infected (HIV antibody- and PCR-positive) patients and non-infected individuals.

SETTING

Hospitalised patients in a referral centre (Red Cross War Memorial Children's Hospital, Cape Town).

PATIENTS

All admissions under 15 months of age who had HIV antibody requested were eligible, provided there was sufficient serum (150 microliter) for further study. Overall, there were 201 symptomatic cases and 49 healthy controls. Twenty of the symptomatic cases were HIV antibody-positive and 19 of these were HIV-infected on the basis of a positive PCR for HIV viral product.

RESULTS

Of the tests we evaluated (total IgG, IgM, IgA and rheumatoid factors of the same classes), raised total IgG level (cut-off 18 g/I or above) was the most useful. We used a commercial radial immunodiffusion plate which was found to have excellent reproducibility (inter-assay coefficient of variation 3.2%). The test detected 16 of 19 infected infants (sensitivity 84%, negative predictive value 98%). With the exception of the finding of oral thrush (odds ratio 7; P < 0.001), the clinical signs at presentation did not distinguish those who were HIV antibody-positive from those who were negative.

CONCLUSIONS

In our study of hospital admissions, the finding of elevated IgG and HIV antibody was diagnostic of HIV infection. (The positive predictive value of the combination was 100%.) Likewise, the presence of raised IgG levels and oral candidosis had a high specificity for HIV infection (98%) but the sensitivity was low (37%). Measurement of total IgG levels by radial immunodiffusion is simple, relatively inexpensive (< 10% of the cost of PCR), helpful in diagnosing HIV infection in symptomatic infants and able to be performed in areas with minimal laboratory back-up.

A comparison of oral and intravenous iron supplementation in preterm infants receiving recombinant erythropoietin

OBJECTIVE

To determine whether intravenously administered iron supplements would improve the hematologic response to recombinant erythropoietin in stable preterm infants.

METHODS

Forty-two preterm infants (<33 weeks' gestation, birth weight < 1500 gm, hematocrit <38%) were treated with recombinant human erythropoietin (Eprex), 600 U/kg per week, and randomly assigned to receive either an oral preparation of ferrous lactate (elemental iron, 12 mg/kg per day) or an intravenous preparation of iron sucrose (6 mg/kg per week).

RESULTS

Hematocrits, reticulocyte counts, and transfusions were similar in the oral group (OG) and the intravenous group (IVG). However, markedly higher serum ferritin concentrations were noted in the IVG (p <0.001), and by completion of the study the arithmetic mean values were 265 +/- 127 microg/L versus 137 +/- 65 microg/L in the IVG and the OG, respectively. The numbers of hypochromic erythrocytes increased in both groups during the study but were significantly higher in the OG (p = 0.04). Mean daily weight gain in the IVG (27 +/- 6.4 gm/day) was greater than in the OG (22.9 +/- 4.78 gm/day; p = 0.04).

CONCLUSIONS

High doses of both orally administered iron and intravenously administered iron sucrose appear to supply sufficient iron for erythropoiesis in stable infants. Storage iron may become depleted after oral supplementation. The intravenous preparation appears to be safe and maintains serum ferritin concentrations, and it may be indicated for patients with low ferritin levels and for those not established on enteral feedings.

Is the use of recombinant human erythropoietin in anaemia of prematurity cost-effective?

In a double-blind placebo-controlled study we showed a 3-fold decrease in blood transfusions (BTFs) given to preterm infants with anaemia of prematurity who received recombinant erythropoietin. However, only 50% of placebo recipients required a BTF. Data from the placebo group indicated that either mean daily weight gain < or = 7.5 g/day before study entry or haematocrit < or = 50% at birth was associated with BTFs (P < 0.001). We calculated that giving erythropoietin to patients in the treatment group with either of these variables prevented 24 of 28 BTFs and that it would cost R184 to prevent 1 BTF. The cost of each BTF was R187 (blood filtered to remove white cells and reduce cytomegalovirus transmission). Therefore, the costs of the two treatments were similar, but as the risk of transmitting infection is lower with erythropoietin, we recommend its use in selected preterm infants.

Comparison of a modified DNA hybridization assay with standard culture enrichment for detecting group B streptococci in obstetric patients

Infection with group B streptococcus (GBS) results in 12,000 to 15,000 cases of neonatal sepsis annually in the United States. GBS is transmitted vertically in up to 70% of infants born to colonized women. Early-onset GBS disease (septicemia, pneumonia, or meningitis occurring within 7 days of life) has a mortality rate of up to 50%, with permanent neurologic sequelae occurring in 15 to 50% of infants surviving meningeal infection. Because of the fulminant nature of neonatal infection, it would be useful to have a rapid assay for determining the GBS status of laboring women. This study illustrated how a commercially available DNA probe-based test was modified to achieve this goal. Modifications included the use of mixed cultures rather than pure isolates for detecting GBS, along with a shorter culture enrichment time and a sample concentration step. To this end, vaginal and rectal swabs from 402 pregnant women during their third trimester were cocultured and tested for GBS rRNA. The 8-h enrichment protocol resulted in an assay with a sensitivity of 95% and specificity of 98%, while the 3-h enrichment protocol revealed a sensitivity of 73% and specificity of 99%. In summary, GBS was detected in the majority of colonized women in less than 4 h. This study illustrated the usefulness of the approach in identifying the most heavily colonized women, who are at the highest risk of transmitting GBS to their neonates. The modified test would have a significant impact on both the medical management and antibiotic therapy for these women and their newborns.

Determination of lymphocyte immunophenotypic values for normal full-term cord blood

Normal reference values for flow cytometric immunophenotypic lymphocyte markers for cord blood (CB) were determined using sufficient numbers of subjects for clinical laboratory use. Samples from 202 normal gestations were processed by whole blood lysis and analyzed in the following combinations: CD14/45, CD4/3, CD8/3, CD45RA/4, CD29/4, CD56/3, Cd19/3, CD19/10. Thirty-five adult laboratory volunteers were analyzed as controls. When compared to adults, CB showed increased relative percentages of naive T-helper cells, B cells, immature B cells, and CD8+3-cells and decreased T cells, cytotoxic T cells, activated T-helper cells, and large granular lymphocytes (CD56+3+). Significant differences were also found when CB samples were stratified by sex and race. These results provide clinical laboratory normal reference values for lymphocyte markers for CB, demonstrate the need for determining separate standard reference values for significantly different patient populations, provide the basis for future investigation of pathologic gestations and for clinical laboratory applications, and provide insight into early immunologic development.

p53, retinoblastoma gene product, and cyclin protein expression in human papillomavirus virus DNA-positive cervical intraepithelial neoplasia and invasive cancer

Human papillomavirus interacts with cyclin protein and tumor suppressor genes, p53, and retinoblastoma gene (Rb). Expression of these gene products was examined in 69 formalin-fixed, paraffin-embedded cervical biopsies by immunohistochemistry utilizing antibodies against p53, Rb, and proliferating cell nuclear antigen (PCNA) and by human papillomavirus DNA in-situ hybridization assays. Samples selected for this study included 27 normal/reactive atypia cases that were all human papillomavirus DNA in-situ hybridization negative, 37 cervical intraepithelial neoplasia (CIN) lesions, and 5 invasive carcinomas. The CIN and invasive carcinoma cases were all human papillomavirus DNA in-situ hybridization positive. p53 protein expression was detected in approximately one-third of the reactive atypia and CIN lesions and in 60% of invasive cancers. Neither the amount or the location of p53 staining was correlated with the histologic diagnosis. Rb staining was more frequently found in the CIN/invasive carcinoma cases compared to the normal/reactive atypia samples (39/42 [93%] versus 21/27 [78%], respectively; P < 0.05 by chi 2. PCNA staining was detected in virtually all samples tested. However, the location of both PCNA and Rb staining differed when the normal/reactive atypia cases were compared to the CIN cases. Only 10% of the former group demonstrated Rb staining throughout the basal two-thirds layer or full thickness of the epithelium compared with 65% of the latter group (P < 0.001 by chi2). Likewise, PCNA staining of the basal two-thirds or full-thickness of the epithelium was found in only 58% of normal/reactive atypia cases, but in 97% of the CIN group (P < 0.001). Our results suggest that the location of Rb and PCNA staining is quite different between normal/reactive atypia cervical biopsies and CIN lesions.

Deficiency of complement factor C5 reduces early mortality but does not prevent organ damage in an animal model of multiple organ dysfunction syndrome

OBJECTIVE

To evaluate the role of complement factor C5 in a model of zymosan-induced multiple organ dysfunction syndrome.

DESIGN

Experimental animal study.

SETTING

Central animal laboratory of a university hospital.

SUBJECTS

Twenty-five C5-deficient B2D10/Old and 25 C5-sufficient B2D10/New mice.

INTERVENTIONS

On day 0, all mice received an intraperitoneal injection with zymosan suspended in paraffin in a dose of 1 mg/g body weight.

MEASUREMENTS AND MAIN RESULTS

Between days 0 and 12, biological parameters (temperature, body weight, and clinical condition) were measured daily and mortality was monitored. Clinical condition was assessed as a symptom score by blindly grading the degree of lethargy, conjunctivitis, diarrhea, and ruffled fur of each mouse on a 2-point scale (maximum score of 4). On day 12, all surviving mice were killed and relative organ weights of lungs, liver, spleen, and kidneys were calculated. Relative organ weight was defined as (organ weight/body weight) x 100%. Zymosan administration induced a typical triphasic illness. Deterioration of the clinical condition, as indicated by the symptom score, and the decrease in temperature and body weight in the acute phase were all significantly less severe in C5-deficient mice (p < .005). In the late phase, no differences could be noticed in the courses of these biological parameters. Overall mortality was 2 (8%) of 25 in C5-deficient mice and 8 (32%) of 25 in C5-sufficient mice (p = .049), a difference that was mainly due to a difference in the acute phase. Organ damage, assessed as the relative organ weights, did not show any statistical differences for any organ between both strains.

CONCLUSIONS

Complement factor C5 appears to play an important role in the acute hyperdynamic septic response in this model. However, deficiency of C5 could not prevent organ damage in the late multiple organ dysfunction syndrome phase. This finding suggests that other factors must be more important in the development of the inflammatory response leading to multiple organ dysfunction syndrome.

Recombinant human erythropoietin in the treatment of the anemia of prematurity: results of a double-blind, placebo-controlled study

OBJECTIVE

To assess the efficacy of recombinant human erythropoietin (rHuEpo) in the treatment of the anemia of prematurity.

METHODOLOGY

A double-blind, placebo-controlled study was conducted on 80 preterm infants (< or = 32 weeks; postnatal age, 2 to 8 weeks; central hematocrit < or = 35%). Patients were randomly assigned to receive subcutaneous rHuEpo (Eprex, 600 U/kg per week) or an equivalent volume of placebo, for up to 6 weeks. All patients received supplements of vitamin E (25 IU) and iron (3 mg/kg per day). The iron supplement was increased if declining serum ferritin measurements were noted.

RESULTS

Treatment and placebo groups did not differ significantly with respect to mean gestational age, birth weight, hematocrit, or reticulocyte count at study entry. Fewer transfusions were administered to those receiving erythropoietin (7 compared with 21; P = .002). Compared with the placebo group, the infants receiving rHuEpo had a higher mean hematocrit (32.3 +/- 4% vs 29.3 +/- 6.2%; P = .014) and absolute reticulocyte count (223 +/- 73 vs 124.9 +/- 73 x 10(9)/L; P < .001) at the end of the study. The mean neutrophil count was not significantly reduced at study exit (P = .8), nor at any other period during the trial in the rHuEpo group. Intercurrent events (mostly infections) were not increased in the treatment group, although there was one case of sudden infant death syndrome at age 4 months.

CONCLUSIONS

Using a dose of rHuEpo of 600 U/kg per week, this study has shown a clear reduction in the requirement for blood transfusion in preterm infants.

Analysis of western blotting (immunoblotting) technique in diagnosis of congenital syphilis

The diagnosis of congenital syphilis in apparently healthy infants continues to be problematic. Immunoglobulin M antibodies specific for a subset of Treponema pallidum antigens have been detected by Western blotting (immunoblotting). In the present study we investigated the sensitivity and specificity of this method. We tested 26 infants aged 0 to 4 months who fulfilled the accepted criteria for the diagnosis of congenital syphilis. There were 14 symptomatic infants. Sera from 13 of these infants were positive for the 47-kDa treponemal antigen (92% sensitivity). The remaining 12 infants were clinically asymptomatic when tested at birth but subsequently displayed features consistent with the disease. Reactive blots (antibodies to the 47- and/or the 15-kDa antigens) were noted in 10 of the 12 infants (83% sensitivity). Thirty infants whose mothers had syphilis were monitored and shown to be uninfected. Nonreactive blots were seen in sera from 27 infants, while sera from 3 older infants had false-positive tests (90% specificity). The Western blotting technique is sensitive (even in the diagnosis of clinically inapparent cases) and, in the absence of immunoglobulin M rheumatoid factor, is a useful confirmatory test for congenital syphilis.

Syphilitic placentitis: an immunopathy

The placentas of eight infants with congenital syphilis were examined by both immunohistochemical and immunofluorescent techniques. Significant IgM, C3 and rheumatoid factor reactivity were observed in all the syphilitic placentas. We postulate that their presence plays an important role in the evolution of the pathological changes.

Detection of human papillomavirus in cervical swab samples by ViraPap and in cervical biopsy specimens by in situ hybridization

Human papillomavirus (HPV) detection in cervical swab specimens by ViraPap and in cervical biopsies by the ViraType in situ hybridization assay was correlated with concurrent cytologic and histologic findings in 149 patients. Seven percent of patients with normal samples were positive for HPV DNA, compared with 29% and 69% of patients with low- and high-grade squamous intraepithelial lesions (SILs), respectively. The performance of both assays increased the rate of HPV detection in low-grade lesions but not in high-grade cases. ViraPap was more sensitive than the ViraType in situ hybridization assay in high-grade lesions. The present investigation suggests that HPV DNA detection may be useful in separating confirmed lesions from histologically questionable biopsies.

Congenital syphilis: the diagnostic value of the rheumatoid factor in symptomatic patients

The rheumatoid factor (RF) latex test was used as a side-room investigation for congenital syphilis. Thirty-four infants aged 0-4 months with suggestive clinical signs and unknown serological tests for syphilis were studied. Nineteen were subsequently diagnosed as having congenital syphilis on the basis of positive serology, while 15 infants had other conditions. The sensitivity of the RF latex test was 95% with a specificity of 80%. Reactive tests were seen only in neonates with congenital infections (p < 0.001). The total IgM test had a similar sensitivity in the diagnosis of congenital syphilis but its specificity (14%) was significantly less (p < 0.001). In areas where the prevalence of congenital syphilis is high, the RF latex test is useful for rapid diagnosis of the condition while confirmatory tests are awaited.

Total IgM levels at birth and in early infancy

Sera obtained from newborns and young infants in an underdeveloped country were subjected to total IgM measurement. The mean (SD) levels at birth (12.4 (2.34) mg/dl) were comparable with those reported in other centres but rose to higher concentrations in the 1st 4 months of life.

IgM rheumatoid factor removal and performance of the FTA-ABS (IgM) test in congenital syphilis

OBJECTIVE

To determine the performance of the FTA-ABS (IgM) test in congenital syphilis after eliminating interference by IgM rheumatoid factor (RF) and preventing competitive inhibition by IgG.

DESIGN

The FTA-ABS (IgM) test was carried out before and after RF removal (achieved by immunoprecipitation of the IgG) in infants with congenital syphilis and controls.

SETTING

Newborns delivered in the Peninsula Maternal and Neonatal Services in Cape Town and infants presenting at Red Cross War Memorial Children's Hospital.

SUBJECTS

Infants with congenital syphilis aged 0-4 months were divided into those with clinical signs at presentation and those who were asymptomatic at delivery. In addition, patients without congenital syphilis but with similar clinical signs at presentation were investigated as were control infants.

OUTCOME MEASURE

The diagnosis of congenital syphilis was based on the criteria suggested by Kaufman et al (1977).

RESULTS

Amongst symptomatic infants with congenital syphilis the FTA-ABS (IgM) test was positive in 34 (92%) of 37 cases prior to abolishing the RF effect and in 29 (78.4%) of 37 cases afterwards (p = 0.19). In 12 cases of congenital syphilis who were asymptomatic at birth, 10 had positive FTA-ABS (IgM) tests before RF removal and only three had positive tests afterwards (p = 0.006). False positive tests were not found amongst 15 symptomatic infants whose clinical features mimicked those of the infants with congenital syphilis. Among 51 healthy infants the test had a false-positive rate of 2% in newborns and 13% in older infants. The false positive reactions were eradicated by IgG precipitation.

CONCLUSIONS

Following IgG and RF removal there was an improvement in the specificity of the FTA-ABS (IgM) test but this was at the expense of a loss of sensitivity, particularly in asymptomatic newborns. For newborns, if the FTA-ABS (IgM) test was positive, the patient was likely to require treatment for congenital syphilis, regardless of whether the result was due to the presence of RF or specific IgM.

IgM rheumatoid factor in congenital syphilis: associations with clinical and laboratory findings

IgM rheumatoid factor (RF), measured by means of an ELISA, was detected in 92% of infants with congenital syphilis. Elevated levels were found to correlate with liver and renal involvement as well as the extent of the disease (P less than 0.05). In addition, levels of circulating immune complexes were closely related to the RF concentration (P less than 0.001). Following treatment of the infants both RF levels and VDRL titres declined at a similar rate (P less than 0.001). These findings indicated a close relationship between the disease process and IgM RF levels. It is postulated that IgM RF may add to immune complex deposition and exacerbate tissue damage in congenital syphilis.

Detection of human papillomavirus DNA in genital lesions by using a modified commercially available in situ hybridization assay

A modified, commercially available DNA-DNA in situ hybridization test that uses biotinylated probes for the identification of human papillomavirus (HPV) DNA types 6/11, 16/18, and 31/33/35 was evaluated. HPV DNA was detected in 314 of 787 (40%) histologically abnormal genital biopsy specimens by using the ViraType in situ assay (Life Technologies, Gaithersburg, Md.), in which the hybridization time was increased from 2 to 16 h. Ninety percent of positive condyloma acuminata specimens contained HPV type 6/11 DNA. The prevalences of HPV DNA for cervical intraepithelial neoplasia I, II, and III lesions by this in situ hybridization test were 42, 54, and 55%, respectively. The combined prevalence of HPV type 16/18 and 31/33/35 DNAs increased with the severity of the lesion, while the prevalence of type 6/11 DNA decreased. HPV type 6/11 DNA was found only in 1 of 16 (6%) positive cervical intraepithelial neoplasia III specimens. HPV type 16/18 and 31/33/35 DNA was detected in 11 of 16 (69%) and 4 of 16 (25%) in situ hybridization-positive cervical intraepithelial neoplasia III specimens, respectively. Thus, the observation that certain "higher-risk" HPV genotypes are associated with upper-grade cervical precancer lesions was confirmed by this commercial hybridization system. In general, the assay was found to be well suited for use in the clinical laboratory. The ViraType in situ procedure modified for a longer hybridization time may be helpful in identifying lesions containing higher-risk HPV strains.

Efficacy of hepatitis B screening in a private obstetrical population

We sought to determine whether the recent Centers for Disease Control recommendation of universal prenatal screening for hepatitis B surface antigen (HBsAg) is necessary or cost-effective in a population of private patients. During the 21 months of our study there were 17,973 deliveries at Magee-Womens Hospital, the largest-volume private obstetrics service in the United States. We screened 12,377 of these patients for HBsAg. Only 11 patients, 0.09% of those screened (5 private and 6 clinic) tested positive. We administered questionnaires regarding historical risk factors for hepatitis B to all 11 patients testing positive for HBsAg and to 100 controls who tested negative for HBsAg. All private patients and 5 of 6 clinic patients testing positive for HBsAg had identifiable risk factors for hepatitis B. In addition, historical risk factors for hepatitis B were identified in 29% of the women testing negative for HBsAg. We found historical risk factors to be excellent predictors of the presence of HBsAg in our private patients. Our data indicate that universal screening for HBsAg is not necessary in private patients.

Risk factors for congenital syphilis

A prospective study of newborns whose mothers had untreated or inadequately treated syphilis was undertaken. The infants were followed up for 3-4 months to ascertain whether they had congenital syphilis. A number of variables were analysed as possible predictive factors for the development of congenital syphilis. A maternal Venereal Disease Research Laboratory (VDRL) titre of 1:32 or above indicated which infants would develop congenital syphilis with a sensitivity of 93% and a specificity of 78%. The risk of a congenitally infected infant was significantly higher amongst the group of untreated mothers (p = 0.036). Low birthweight per se did not appear to be a predictor of the subsequent diagnosis of congenital syphilis. Using these simple predictive factors it may be possible to determine which at-risk infants would most benefit from careful supervision or a full 10-day course of therapy.

Demonstration of human papillomavirus DNA by nucleic acid in situ hybridization in paired histologically abnormal cervical biopsies obtained at the same patient visit

Fifty-four pairs of cervical biopsies ranging from minimal dysplasia to severe dysplasia were studied for the presence of human papillomavirus DNA by in situ hybridization. Two assays were performed on each biopsy. A 16 hour hybridization was used in one assay, while a 40 hour hybridization was utilized in the second assay. Increasing the hybridization time to 40 hours did not significantly increase the detection rate of HPV compared to the rate found using the 16 hour hybridization. Also, no difference in the detection rate of HPV was found by using one biopsy of the pair over the other biopsy of the pair. However, the performance of a single in situ assay on only one biopsy from each patient significantly underestimated the true prevalence of HPV. A single assay only detected 21/33 (64%) patients with HPV. Implications of multiple testing of all histologically abnormal biopsies is discussed in relation to prospective follow-up studies determining the usefulness of HPV typing in patient management.

Detection of human papillomavirus DNA in cervical lesions by in situ hybridization using biotinylated DNA probes

In situ hybridization (ISH) for human papillomavirus (HPV)-6, -11, -16, -18, and -31 DNA was performed on 615 formalin-fixed paraffin-embedded cervical biopsies using biotinylated DNA probes. Results were obtained from 584 samples with 266 (45.5%) containing HPV-DNA sequences. Ninety percent of condyloma acuminatum specimens were positive for HPV-DNA with 18 of 19 positive cases containing HPV-6 or -11 DNA. The detection rate of HPV in cervical intraepithelial neoplasia (CIN) lesions was 50.6% (239 of 472), while only 8 of 91 (8.9%) cervical biopsies considered to be histologically normal or with minimal dysplasia contained HPV-DNA as demonstrated by ISH. The prevalence of HPV-16, -18, and/or -31 DNA increased with the severity of the lesions, with 20 of 20 (100%) positive CIN-III lesions containing these viral types compared with 102 of 157 (65.0%) positive CIN-I lesions. ISH with biotinylated DNA probes appears helpful in identifying lesions containing higher risk viral strains.

In-situ hybridization for the diagnosis and typing of human papillomavirus

The human papillomavirus (HPV) has been associated with the production of many skin and mucosal lesions, the development of squamous cell carcinoma of the genital areas, skin and aerodigestive tracts, and possibly adenocarcinoma of the uterine cervix. There are more than 60 known genotypes of HPV. Some genotypes have been associated with lesions that have none or minimal chances of malignant transformation; while other genotypes (especially types 16, 18, 31, 35, and 51) have been found in mild, moderate, and severe dysplasia, carcinoma in-situ or frank invasive carcinoma. HPV cannot be propagated in tissue cultures. The presence of the virus can be demonstrated by immunologic techniques, which are not sensitive enough with the present methodology, or by searching for the presence of the viral DNA by DNA or RNA hybridization techniques. Determining the viral genotype in the tissue involved will permit the separation of those lesions supposedly to be low risk from those associated with the high risk types. This knowledge may be helpful in the future to determine the appropriate management of patients infected with HPV.

Rheumatoid factor in congenital syphilis

The rheumatoid factor (RF) latex test was evaluated as a test for congenital syphilis. High risk newborns of mothers with untreated or inadequately treated syphilis were studied. The asymptomatic infants were followed up for between 3 and 4 months (or longer if the VDRL test was positive). The overall performance of the RF latex test was better than that of the other tests studied, even though the sensitivity was 46.7%. The specificity and positive predictive value of the test were 100% whilst the negative predictive value was 86.4%. The test was negative in all 84 controls studied. Although a negative RF latex test cannot be used to exclude congenital syphilis in an asymptomatic infant, a positive test in the presence of maternal syphilis should lead one to strongly suspect congenital syphilis.

Characteristics of recurrent genital herpes simplex infections in pregnant women

Longitudinal study of 229 pregnancies in 186 pregnant women with recurrent genital herpes simplex virus (HSV) infections revealed an increased incidence of recurrent episodes in the third trimester compared with the first or second trimesters. The duration of symptomatic recurrences did not change with each trimester. Cervical HSV shedding concomitant with HSV culture-positive vulvar lesions did not change significantly with advancing gestation. The presence of an HSV culture-positive vulvar lesion indicated a significantly (P less than .001) greater risk of concomitant cervical HSV shedding (44 of 333, 13.2%) than in pregnant women with HSV culture-positive remote lesions (zero of 60) or in asymptomatic women (27 of 1460, 1.9%). Comparison of the characteristics among 43 pairs of pregnancies in 34 women revealed no consistent change over time. This study of the natural history of genital HSV recurrences in pregnant women demonstrated no proclivity for an increased rate of preterm delivery (1.3%) or congenital anomalies (2.2%) in a predominantly white, non-Hispanic middle-class population.

Transient dyserythropoiesis occurring during the involutionary phase of stage IV-S neuroblastoma

An acutely ill 6-month-old female infant presented with massive hepatomegaly, accompanied by severe anemia with peripheral normoblastemia and thrombocytopenia. Bone marrow examination revealed erythroid hyperplasia with gross erythroid dysplasia, reduced granulocytic precursors, and virtually absent megakaryocytes. The bone marrow also contained completely necrotic cells occurring in clumps as well as singly. The appearances suggested bone marrow involvement by neuroblastoma. Accordingly, combination chemotherapy was instituted and laparotomy was performed as soon as her clinical condition had improved. Left adrenalectomy was carried out, because a small adrenal nodule of ganglioneuroma was present. Liver biopsy showed expansion of portal tracts by loose fibrous connective tissue containing hemosiderin deposits and some degenerate cellular debris, consistent with areas of involuted metastatic neuroblastoma. Complete recovery followed, and subsequent bone marrow examination was entirely normal. It is thought that the dyserythropoiesis probably resulted from the release of toxic metabolites from regressing neuroblastoma.

Isolation of genital mycoplasmas and Chlamydia trachomatis in stillborn and neonatal autopsy material

Chlamydia trachomatis and the genital mycoplasmas are significantly prevalent in sexually active women. How these organisms may affect the outcome of pregnancy and the neonate was the principal thrust of this investigation. Placenta, liver, and lung tissue were cultured from Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis, and aerobic as well as anaerobic bacteria in 432 stillborn and neonatal autopsies. Genital mycoplasmas were isolated from 36 cases (8.3%). Acute chorioamnionitis and funisitis were present significantly more often in cases with genital mycoplasma than in those without these organisms. Isolation of genital mycoplasmas was not associated with an increased incidence of intrauterine fetal death, villitis, hyaline membrane disease, congenital anomalies, or polymorphonuclear leukocytes in alveolar spaces. Chlamydia trachomatis was not found in any of the sites sampled.

Immunodiagnosis of adult chlamydial conjunctivitis

This study presents data from a prospective comparison of four currently available diagnostic tests for Chlamydia trachomatis infection. Seventy-six patients clinically suspicious for chlamydial conjunctivitis were all tested with Giemsa stain cytology, direct monoclonal fluorescent antibody (DFA) microscopy, enzyme immunosorbent assay (EIA) for chlamydial antigens, and standard McCoy cell culture. When compared with primary cell culture, diagnostic Giemsa inclusions had a sensitivity and specificity of 43 and 100%, respectively, supportive Giemsa cytology 71 and 67%, the enzyme immunoassay 71 and 97%, and the monoclonal fluorescent antibody 57 and 81%. Each nonculture method has distinct advantages in terms of cost, technical difficulty, speed, and accuracy, which dictate selection of the most appropriate test for office or laboratory diagnosis of chlamydial conjunctivitis.