Paul N. Goldwater

Neurotropic viruses and cerebral palsy: population based case-control study

Abstract Objective To investigate the association between cerebral palsy and direct evidence for perinatal exposure to neurotropic viruses. Design Population based case-control study. Setting Adelaide Womens and Childrens Hospital Research Laboratory. Participants and main outcome measures Newborn screening cards of 443 white case patients with cerebral palsy and 883 white controls were tested for viral nucleic acids from enteroviruses and herpes viruses by using polymerase chain reaction. Herpes group A viruses included herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpes virus 8 (HHV-8), and herpes group B viruses included varicella zoster virus (VZV) and human herpes viruses 6 and 7 (HHV-6 and HHV-7). Results The prevalence of viral nucleic acids in the control population was high: 39.8% of controls tested positive, and the prevalence was highest in preterm babies. The detection of herpes group B viral nucleic acids increased the risk of developing cerebral palsy (odds ratio 1.68, 95% confidence interval 1.09 to 2.59). Conclusions Perinatal exposure to neurotropic viruses is associated with preterm delivery and cerebral palsy.

Toxigenic Escherichia coli Associated with Sudden Infant Death Syndrome

The role of Escherichia coli as a cause of sudden infant death syndrome was investigated prospectively. Strains of E. coli producing the heat labile enterotoxin (LT) or the Vero-cell cytotoxin (VT) were isolated from the intestinal contents of 21/46 infants who died from sudden infant death syndrome (SIDS). None were found in the contemporaneously sampled faeces of 24 normal live infants in the same area. Live infants were used as controls in the absence of dead infants who had not died of SIDS. This high incidence of toxigenic E. coli among the SIDS infants versus the low incidence in controls, together with the general rarity of finding such toxigenic E. coli in the community of a temperate developed country, made us conclude that there may be a causal relationship between toxigenic E. coli and SIDS. The O and H serotypes of the toxigenic E. coli associated with SIDS infants tended not to be those normally considered to be toxigenic. The toxigenicity appeared to be relatively labile. It is suggested that SIDS may be associated with the infant either acquiring these unusual types of E. coli or more likely that its normal resident E. coli acquire the plasmids to produce these toxins.

Cloning and nucleotide sequence of a variant Shiga-like toxin II gene from Escherichia coli OX3:H21 isolated from a case of sudden infant death syndrome☆

Escherichia coli OX3:H21 expressing a toxin related to Shiga-like toxin (SLT) was isolated from the small bowel contents of a case of Sudden Infant Death Syndrome (SIDS). This strain was lysogenic for a lambdoid bacteriophage, but this did not encode the toxin. Southern hybridization analysis of chromosomal DNA revealed that the SLT-related gene was located on a 4.6 kb PstI fragment, which was cloned into E. coli JM109 in both orientations, using the vector pUC19, to generate plasmids pJCP501 and pJCP502. JM109 cells harbouring the recombinant plasmid produced SLT, as judged by cytotoxicity for Vero cells. Nucleotide sequence analysis revealed that the SLT gene was related to, but distinct from, previously reported variants of Shiga-like toxin type II, produced by E. coli from both human and animal sources. The A subunit of the SLT gene from OX3:H21 exhibited 95.9% homology (at both the DNA and derived amino acid sequence level) to the A subunit of the most closely related SLT-II variant. The B subunit was less similar, exhibiting 88.6 and 88.8% homology to the related gene at the DNA and amino acid level, respectively.

Treatment of enterohemorrhagic Escherichia coli (EHEC) infection and hemolytic uremic syndrome (HUS)

Verotoxigenic Escherichia coli (VTEC) are a specialized group of E. coli that can cause severe colonic disease and renal failure. Their pathogenicity derives from virulence factors that enable the bacteria to colonize the colon and deliver extremely powerful toxins known as verotoxins (VT) or Shiga toxins (Stx) to the systemic circulation. The recent devastating E. coli O104:H4 epidemic in Europe has shown how helpless medical professionals are in terms of offering effective therapies. By examining the sources and distribution of these bacteria, and how they cause disease, we will be in a better position to prevent and treat the inevitable future cases of sporadic disease and victims of common source outbreaks. Due to the complexity of pathogenesis, it is likely a multitargeted approach is warranted. Developments in terms of these treatments are discussed.See related article: http://www.biomedcentral.com/1741-7015/10/11

Rotavirus encephalopathy: Pathogenesis reviewed

Abstract: Two cases of rotavirus gastroenteritis associated with neurological involvement, one with encephalitis (defined by abnormal neurological signs, cerebrospinal fluid (CSF) pleocytosis and detection of rotavirus genomic nucleic acid in the CSF) and one with a non‐inflammatory encephalopathy (defined by abnormal neurological signs, an entirely normal CSF and detection of rotavirus genomic nucleic acid in the CSF), are presented and used as a basis to review and explore potential pathogenetic mechanisms, including direct viral replication within neurons and indirect effects of the newly described rotavirus ‘enterotoxin’.

Genetic polymorphisms and spontaneous preterm birth.

OBJECTIVE: To examine whether selected genetic polymorphisms in the infant are associated with spontaneous preterm birth (less than 37 weeks) among children with or without later-diagnosed cerebral palsy. METHODS: Exploratory case–control study investigating the relationship of gestational age at delivery to 31 single nucleotide polymorphisms measured in newborn screening bloodspots. Among all 443 children with later-diagnosed cerebral palsy born to white women in South Australia in 1986–1999, 234 were born after spontaneous onset of labor, and 108 of these were preterm (gestational age less than 37 weeks). The comparison group was 549 infants born after spontaneous onset of labor, of whom 147 were preterm. Distributions of genotypic frequencies were examined in preterm compared with term infants with and without cerebral palsy. Genotyping was performed using a Taqman assay. RESULTS: In children without cerebral palsy, preterm birth after spontaneous onset of labor was more frequent in association with a variant of the β2 adrenergic receptor gene (ADRB2 Q27E, P=.003), inducible nitric oxide synthase (iNOS or NOS2A, P=.042), or thrombomodulin (G127A, P=.006). Among children with cerebral palsy, preterm birth was associated with polymorphisms in genes for endothelial nitric oxide synthase (eNOS -922, P=.012), plasminogen activator inhibitor-2 (P=.015 and .019), and alpha adducin (ADD1, P=.047). CONCLUSION: We confirm previous observations that variants of the β adrenergic receptor and of nitric oxide synthase are associated with prematurity, and suggest that genetic variants of the placental antifibrinolytic plasminogen activator inhibitor-2, and thrombomodulin and alpha adducin may be contributors to risk of spontaneous preterm birth. LEVEL OF EVIDENCE: II

Sequence of a variant Shiga-like toxin type-I operon of Escherichia coli O111:H−

PCR amplification was used to screen faecal isolates of Escherichia coli from a 12-month-old boy with haemolytic uraemic syndrome for the presence of Shiga-like toxin (SLT)-encoding genes. One isolate, belonging to serotype O111:H-, was positive for SLT-I by this method. UV induction indicated that the strain was lysogenic for a lambdoid bacteriophage, but this did not encode the toxin. Southern hybridization analysis of chromosomal DNA revealed that the SLT-I gene was located on an 8.5-kb EcoRI fragment. SLT-I was further localized to within a 3.0-kb SphI-EcoRI fragment. A separate subclone contained a 3.75-kb HindIII fragment, 1.18 kb of which was common to both. Nucleotide sequence analysis of derivatives of these clones revealed that the SLT-I A subunit gene from E. coli O111:H- differed from the previously published sequences for SLT-I by 5 bp [resulting in two amino acid (aa) changes]. It was more closely related to the gene encoding the A subunit of the Shiga toxin from Shigella dysenteriae type 1, from which it differed by 3 bp (resulting in one aa change). The DNA sequence of the B subunit-encoding gene was identical to that of the other two toxins. The region of DNA upstream from the SLT-I of E. coli O111:H- contained an IS element, as well as a region with strong homology to a portion of the genome of bacteriophage lambda.

Epidemiologic associations with cerebral palsy

OBJECTIVE: To estimate epidemiologic risk factors for cerebral palsy. METHODS: Data were collected by linkage to state-based perinatal repositories and cerebral palsy registers and using a maternal questionnaire. The cohort included 587 individuals with cerebral palsy and 1,154 non–cerebral palsy controls. RESULTS: The following factors were associated with cerebral palsy: recorded maternal infection during pregnancy (41.4% patients compared with 31.3% controls; odds ratio [OR] 1.55, 95% confidence interval 1.26–1.91), small for gestational age ([birth weight less than third customized centile] 43.9% patients compared with 6.3% controls; OR 11.75, 6.25–22.08), gestational age less than 32 weeks (29.3% patients compared with 0.7% controls; OR 59.20, 28.87–121.38), multiple birth (OR 6.62, 4.00–10.95), a relative with cerebral palsy (OR 1.61, 1.12–2.32), breech position (13.7% patients compared with 6.0% controls; OR 2.48, 1.76–3.49), bleeding at any time in pregnancy (29.3% patients compared with 16.9% controls; OR 2.04, 1.61–2.58), male sex (58.8% patients compared with 45.8% controls; OR 1.68, 1.38–2.06), multiple miscarriage (7.7% patients compared with 3.5% controls; OR 2.30, 1.38–3.82), smoking (14.0% patients compared with 10.6% controls; OR 1.37, 1.02–1.85), and illicit drug use (3.3% patients compared with 1.5% controls; OR 2.22, 1.14–4.30). Factors not associated with cerebral palsy were “disappearing twin,” diabetes, maternal body mass index, hypertension, alcohol consumption, anemia, maternal hypothyroidism, forceps or vacuum delivery, and maternal age. CONCLUSION: Preterm birth, intrauterine growth restriction, perinatal infection, and multiple birth present the largest risks for a cerebral palsy outcome. Reassuringly, upper respiratory tract and gastrointestinal infections during pregnancy were not associated with cerebral palsy. LEVEL OF EVIDENCE: II

Candidate Genes and Cerebral Palsy: A Population-Based Study

OBJECTIVE. The objective of this study was to examine whether selected genetic polymorphisms in the infant are associated with later-diagnosed cerebral palsy. METHODS. A population-based case-control study was conducted of 28 single-nucleotide polymorphisms measured in newborn screening blood spots. A total of 413 children with later-diagnosed cerebral palsy were born to white women in South Australia in 1986–1999, and there were 856 control children. Distributions of genotypic frequencies were examined in total cerebral palsy, in gestational age groups, and by types of cerebral palsy and gender. Genotyping was performed by using a TaqMan assay. RESULTS. For inducible nitric-oxide synthase, possession of the T allele was more common in all children with cerebral palsy and for heterozygotes who were born at term. For lymphotoxin α, homozygous variant status was associated with risk for cerebral palsy and with spastic hemiplegic or quadriplegic cerebral palsy. Among term infants, heterozygosity for the endothelial protein C receptor single-nucleotide polymorphism was more frequent in children with cerebral palsy. In preterm infants, the variant A allele of interleukin 8 and heterozygosity for the β-2 adrenergic receptor were associated with cerebral palsy risk. Interleukin 8 heterozygote status was associated with spastic diplegia. Variants of several genes were associated with cerebral palsy in girls but not in boys. CONCLUSIONS. Two of the 28 single-nucleotide polymorphisms examined were associated with all types of spastic cerebral palsy in both gestational age groups and others with cerebral palsy in gestational age or cerebral palsy subgroups. Some of these associations support previous findings. There may be a genetic contribution to cerebral palsy risk, and additional investigation is warranted of genes and gene-environment interactions in cerebral palsy.

Antenatal causes of cerebral palsy: associations between inherited thrombophilias, viral and bacterial infection, and inherited susceptibility to infection

Cerebral palsy rates of 2 in every 1000 births have varied little over the last 40 years, despite improvements in obstetric care. In the past, cerebral palsy was thought to be due to poor obstetric care and management; however, epidemiological studies have refuted this, suggesting that there is usually an antenatal timing to the neuropathology of cerebral palsy. There are many known risk factors for cerebral palsy, including multiple gestation, prematurity, and low birth weight. Recently, intrauterine infection, maternal pyrexia, and the presence of thrombophilic disorders (thrombophilia) have been identified as major risk factors for subsequent cerebral palsy. This review examines the links between intrauterine infection, the fetal inflammatory response, and thrombophilia as possible causes of cerebral palsy. The interactions of viral or bacterial infections during pregnancy, normal or abnormal fetal cytokine responses, and hereditary fetal thrombophilias as antenatal causes of the neuropathology of cerebral palsy are now areas of research priority. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader will be able to describe the condition cerebral palsy, list the risk factors for the development of cerebral palsy, ouline the ultrasound findings associated with cerebral palsy, and point out other conditions associated with cerebral palsy.