Diagnosis of inborn errors of metabolism through prenatal exome sequencing with targeted analysis for fetal structural anomalies

OBJECTIVES

The value of prenatal exome sequencing (pES) for fetuses with structural anomalies is widely reported. In England, testing is conducted through trio exome sequencing and analysis of a gene panel. Over a 30-month period testing of 921 pregnancies resulted in a genetic diagnosis in 32.8% of cases (302/921). Here we review cases diagnosed with an inborn error of metabolism.

METHODS

Diagnoses of inborn errors of metabolism (IEM) were classified according to the ICIMD classification system. Genetic diagnoses were assessed against Human Phenotype Ontology terms, gestation of scan findings and literature evidence.

RESULTS

35/302 diagnoses (11.6%) represented IEM. Almost half affected metabolism of complex macromolecules and organelles (n = 16), including congenital disorders of glycosylation (n = 8), peroxisome biogenesis disorders (n = 4), and lysosomal storage disorders (n = 4). There were eight disorders of lipid metabolism and transport, the majority being genes in the cholesterol biosynthesis pathway, eight disorders of intermediary metabolism, of which seven were defects in "energy" processes, and two diagnoses of alkaline phosphatase deficiency.

CONCLUSIONS

Review of pES diagnoses and ultrasound scan findings is key to understanding genotype-phenotype correlations. IEM are genetically heterogeneous and may present with variable scan findings, which makes an individual diagnosis difficult to suspect. Diagnosis during pregnancy is particularly important for many IEM with respect to prognosis and early neonatal management.

ZTTK syndrome: Clinical and molecular findings of 15 cases and a review of the literature

Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is caused by de novo loss-of-function variants in the SON gene (MIM #617140). This multisystemic disorder is characterized by intellectual disability, seizures, abnormal brain imaging, variable dysmorphic features, and various congenital anomalies. The wide application and increasing accessibility of whole exome sequencing (WES) has helped to identify new cases of ZTTK syndrome over the last few years. To date, there have been approximately 45 cases reported in the literature. Here, we describe 15 additional individuals with variants in the SON gene, including those with missense variants bringing the total number of known cases to 60. We have reviewed the clinical and molecular data of these new cases and all previously reported cases to further delineate the most common as well as emerging clinical findings related to this syndrome. Furthermore, we aim to delineate any genotype-phenotype correlations specifically for a recurring pathogenic four base pair deletion (c.5753_5756del) along with discussing the impact of missense variants seen in the SON gene.

Impaired eIF5A function causes a Mendelian disorder that is partially rescued in model systems by spermidine

The structure of proline prevents it from adopting an optimal position for rapid protein synthesis. Poly-proline-tract (PPT) associated ribosomal stalling is resolved by highly conserved eIF5A, the only protein to contain the amino acid hypusine. We show that de novo heterozygous EIF5A variants cause a disorder characterized by variable combinations of developmental delay, microcephaly, micrognathia and dysmorphism. Yeast growth assays, polysome profiling, total/hypusinated eIF5A levels and PPT-reporters studies reveal that the variants impair eIF5A function, reduce eIF5A-ribosome interactions and impair the synthesis of PPT-containing proteins. Supplementation with 1 mM spermidine partially corrects the yeast growth defects, improves the polysome profiles and restores expression of PPT reporters. In zebrafish, knockdown eif5a partly recapitulates the human phenotype that can be rescued with 1 µM spermidine supplementation. In summary, we uncover the role of eIF5A in human development and disease, demonstrate the mechanistic complexity of EIF5A-related disorder and raise possibilities for its treatment.

Heterozygous lamin B1 and lamin B2 variants cause primary microcephaly and define a novel laminopathy

PURPOSE

Lamins are the major component of nuclear lamina, maintaining structural integrity of the nucleus. Lamin A/C variants are well established to cause a spectrum of disorders ranging from myopathies to progeria, termed laminopathies. Phenotypes resulting from variants in LMNB1 and LMNB2 have been much less clearly defined.

METHODS

We investigated exome and genome sequencing from the Deciphering Developmental Disorders Study and the 100,000 Genomes Project to identify novel microcephaly genes.

RESULTS

Starting from a cohort of patients with extreme microcephaly, 13 individuals with heterozygous variants in the two human B-type lamins were identified. Recurrent variants were established to be de novo in nine cases and shown to affect highly conserved residues within the lamin ɑ-helical rod domain, likely disrupting interactions required for higher-order assembly of lamin filaments.

CONCLUSION

We identify dominant pathogenic variants in LMNB1 and LMNB2 as a genetic cause of primary microcephaly, implicating a major structural component of the nuclear envelope in its etiology and defining a new form of laminopathy. The distinct nature of this lamin B-associated phenotype highlights the strikingly different developmental requirements for lamin paralogs and suggests a novel mechanism for primary microcephaly warranting future investigation.

Telephone outreach by community workers to improve uptake of NHS Health Checks in more deprived localities and minority ethnic groups: a qualitative investigation of implementation

BACKGROUND

NHS Health Checks is a national cardiovascular risk assessment and management programme in England. To improve equity of uptake in more deprived, and Black, Asian and minority ethnic (BAME) communities, a novel telephone outreach intervention was developed. The outreach call included an invitation to an NHS Health Check appointment, lifestyle questions, and signposting to lifestyle services. We examined the experiences of staff delivering the intervention.

METHODS

Thematic analysis of semi-structured interviews with 10 community Telephone Outreach Workers (TOWs) making outreach calls, and 5 Primary Care Practice (PCP) staff they liaised with. Normalization Process Theory was used to examine intervention implementation.

RESULTS

Telephone outreach was perceived as effective in engaging patients in NHS Health Checks and could reduce related administration burdens on PCPs. Successful implementation was dependent on support from participating PCPs, and tensions between the intervention and other PCP priorities were identified. Some PCP staff lacked clarity regarding the intervention aim and this could reduce the potential to capitalize on TOWs' specialist skills.

CONCLUSIONS

To maximize the potential of telephone outreach to impact equity, purposeful recruitment and training of TOWs is vital, along with support and integration of TOWs, and the telephone outreach intervention, in participating PCPs.

Are You In or Are You Out? The Importance of Group Saliency in Own-Group Biases in Face Recognition

Previous research has demonstrated several own-group biases (OGBs) in face recognition, but why they occur is unclear. Social-cognitive accounts suggest they stem from differential attention and facial processing, following the categorisation of a face as belonging to an "in" or "out" group. Three studies explored whether OGBs can be produced by mere categorisation at encoding and investigated the role of in-group membership saliency on face recognition. Participants saw 40 facial images fictionally grouped according to in-/out-group status. Studies 1 and 2 used university membership as the grouping variable and found no evidence of an OGB, and no relationship between OGB magnitude and salience of group membership. Study 3 used the same design as Study 2, but with a highly salient group characteristic: participants' stance on the U.K. Referendum (i.e., whether they were "Leave" or "Remain" supporters). In this case, an asymmetrical OGB was found, with only Remain voters demonstrating an OGB. Furthermore, a relationship between OGB magnitude and attitude toward the Referendum result was found. Overall, our results suggest that social categorisation and membership saliency alone may not be enough to moderate in- and out-group face recognition. However, when sufficiently polarised groups are used as in-/out-group categories, OGBs may occur.

Bi-allelic Loss-of-Function CACNA1B Mutations in Progressive Epilepsy-Dyskinesia

The occurrence of non-epileptic hyperkinetic movements in the context of developmental epileptic encephalopathies is an increasingly recognized phenomenon. Identification of causative mutations provides an important insight into common pathogenic mechanisms that cause both seizures and abnormal motor control. We report bi-allelic loss-of-function CACNA1B variants in six children from three unrelated families whose affected members present with a complex and progressive neurological syndrome. All affected individuals presented with epileptic encephalopathy, severe neurodevelopmental delay (often with regression), and a hyperkinetic movement disorder. Additional neurological features included postnatal microcephaly and hypotonia. Five children died in childhood or adolescence (mean age of death: 9 years), mainly as a result of secondary respiratory complications. CACNA1B encodes the pore-forming subunit of the pre-synaptic neuronal voltage-gated calcium channel Ca_v2.2/N-type, crucial for SNARE-mediated neurotransmission, particularly in the early postnatal period. Bi-allelic loss-of-function variants in CACNA1B are predicted to cause disruption of Ca²⁺ influx, leading to impaired synaptic neurotransmission. The resultant effect on neuronal function is likely to be important in the development of involuntary movements and epilepsy. Overall, our findings provide further evidence for the key role of Ca_v2.2 in normal human neurodevelopment.

De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome

BACKGROUND

Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity).

METHODS

Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes.

RESULTS

We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances.

CONCLUSIONS

TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.

ZMIZ1 Variants Cause a Syndromic Neurodevelopmental Disorder

ZMIZ1 is a coactivator of several transcription factors, including p53, the androgen receptor, and NOTCH1. Here, we report 19 subjects with intellectual disability and developmental delay carrying variants in ZMIZ1. The associated features include growth failure, feeding difficulties, microcephaly, facial dysmorphism, and various other congenital malformations. Of these 19, 14 unrelated subjects carried de novo heterozygous single-nucleotide variants (SNVs) or single-base insertions/deletions, 3 siblings harbored a heterozygous single-base insertion, and 2 subjects had a balanced translocation disrupting ZMIZ1 or involving a regulatory region of ZMIZ1. In total, we identified 13 point mutations that affect key protein regions, including a SUMO acceptor site, a central disordered alanine-rich motif, a proline-rich domain, and a transactivation domain. All identified variants were absent from all available exome and genome databases. In vitro, ZMIZ1 showed impaired coactivation of the androgen receptor. In vivo, overexpression of ZMIZ1 mutant alleles in developing mouse brains using in utero electroporation resulted in abnormal pyramidal neuron morphology, polarization, and positioning, underscoring the importance of ZMIZ1 in neural development and supporting mutations in ZMIZ1 as the cause of a rare neurodevelopmental syndrome.

De Novo Variants in the F-Box Protein FBXO11 in 20 Individuals with a Variable Neurodevelopmental Disorder

Next-generation sequencing combined with international data sharing has enormously facilitated identification of new disease-associated genes and mutations. This is particularly true for genetically extremely heterogeneous entities such as neurodevelopmental disorders (NDDs). Through exome sequencing and world-wide collaborations, we identified and assembled 20 individuals with de novo variants in FBXO11. They present with mild to severe developmental delay associated with a range of features including short (4/20) or tall (2/20) stature, obesity (5/20), microcephaly (4/19) or macrocephaly (2/19), behavioral problems (17/20), seizures (5/20), cleft lip or palate or bifid uvula (3/20), and minor skeletal anomalies. FBXO11 encodes a member of the F-Box protein family, constituting a subunit of an E3-ubiquitin ligase complex. This complex is involved in ubiquitination and proteasomal degradation and thus in controlling critical biological processes by regulating protein turnover. The identified de novo aberrations comprise two large deletions, ten likely gene disrupting variants, and eight missense variants distributed throughout FBXO11. Structural modeling for missense variants located in the CASH or the Zinc-finger UBR domains suggests destabilization of the protein. This, in combination with the observed spectrum and localization of identified variants and the lack of apparent genotype-phenotype correlations, is compatible with loss of function or haploinsufficiency as an underlying mechanism. We implicate de novo missense and likely gene disrupting variants in FBXO11 in a neurodevelopmental disorder with variable intellectual disability and various other features.

Enhanced skills in periodontology: evaluation of a pilot scheme for general dental practitioners and dental care professionals in London

Background The need for periodontal management is great and increasing; thus, the oral and dental workforce should be suitably equipped to deliver contemporary care. Health Education London developed a training scheme to extend the skills of dentists and dental care professionals (DCPs).Aim To examine the feasibility of assessing a skill-mix initiative established to enhance skills in clinical periodontology involving the views of patients, clinicians and key stakeholders, together with clinical and patient outcomes in London.Methods This mixed methods feasibility and pilot study involved four parallel elements: a postal questionnaire survey of patients; analysis of clinical logbooks; self-completion questionnaire survey of clinicians; and semi-structured interviews of key stakeholders, including clinicians.Results Twelve of the 19 clinicians participated in the evaluation, returning completed questionnaires (63%) and providing access to log diaries and patients. Periodontal data from 42 log-diary cases (1,103 teeth) revealed significant improvement in clinical outcomes (P = 0.001 for all). Eighty-four percent (N = 99) of the 142 patients returning a questionnaire reported improved dental health; however, responses from hospital patients greatly exceeded those from dental practice. Interviews (N = 22) provided evidence that the programme contributed to professional healthcare across four key domains: 'service', 'quality care', 'professional' and 'educational'. Clinicians, while supportive of the concept, raised concerns regarding the mismatch of their expectations and its educational and service outcomes.Discussion The findings suggest that it is feasible to deliver and evaluate inter-professional extended skills training for dentists and dental care professionals, and this may be evaluated using mixed methods to examine outcomes including clinical log diaries, patient questionnaires and stakeholder interviews. This inter-professional course represents a positive development for patient care using the expertise of different members of the dental team; however, its formal integration to the health and educational sectors require further consideration.

Genetic heterogeneity in Cornelia de Lange syndrome (CdLS) and CdLS-like phenotypes with observed and predicted levels of mosaicism

BACKGROUND

Cornelia de Lange syndrome (CdLS) is a multisystem disorder with distinctive facial appearance, intellectual disability and growth failure as prominent features. Most individuals with typical CdLS have de novo heterozygous loss-of-function mutations in NIPBL with mosaic individuals representing a significant proportion. Mutations in other cohesin components, SMC1A, SMC3, HDAC8 and RAD21 cause less typical CdLS.

METHODS

We screened 163 affected individuals for coding region mutations in the known genes, 90 for genomic rearrangements, 19 for deep intronic variants in NIPBL and 5 had whole-exome sequencing.

RESULTS

Pathogenic mutations [including mosaic changes] were identified in: NIPBL 46 [3] (28.2%); SMC1A 5 [1] (3.1%); SMC3 5 [1] (3.1%); HDAC8 6 [0] (3.6%) and RAD21 1 [0] (0.6%). One individual had a de novo 1.3 Mb deletion of 1p36.3. Another had a 520 kb duplication of 12q13.13 encompassing ESPL1, encoding separase, an enzyme that cleaves the cohesin ring. Three de novo mutations were identified in ANKRD11 demonstrating a phenotypic overlap with KBG syndrome. To estimate the number of undetected mosaic cases we used recursive partitioning to identify discriminating features in the NIPBL-positive subgroup. Filtering of the mutation-negative group on these features classified at least 18% as 'NIPBL-like'. A computer composition of the average face of this NIPBL-like subgroup was also more typical in appearance than that of all others in the mutation-negative group supporting the existence of undetected mosaic cases.

CONCLUSIONS

Future diagnostic testing in 'mutation-negative' CdLS thus merits deeper sequencing of multiple DNA samples derived from different tissues.

Multimodal imaging enables early detection and characterization of changes in tumor permeability of brain metastases

Our goal was to develop strategies to quantify the accumulation of model therapeutics in small brain metastases using multimodal imaging, in order to enhance the potential for successful treatment. Human melanoma cells were injected into the left cardiac ventricle of immunodeficient mice. Bioluminescent, MR and PET imaging were applied to evaluate the limits of detection and potential for contrast agent extravasation in small brain metastases. A pharmacokinetic model was applied to estimate vascular permeability. Bioluminescent imaging after injecting d-luciferin (molecular weight (MW) 320 D) suggested that tumor cell extravasation had already occurred at week 1, which was confirmed by histology. 7T T1w MRI at week 4 was able to detect non-leaky 100 μm sized lesions and leaky tumors with diameters down to 200 μm after contrast injection at week 5. PET imaging showed that (18)F-FLT (MW 244 Da) accumulated in the brain at week 4. Gadolinium-based MRI tracers (MW 559 Da and 2.066 kDa) extravasated after 5 weeks (tumor diameter 600 μm), and the lower MW agent cleared more rapidly from the tumor (mean apparent permeabilities 2.27 × 10(-5)cm/s versus 1.12 × 10(-5)cm/s). PET imaging further demonstrated tumor permeability to (64)Cu-BSA (MW 65.55 kDa) at week 6 (tumor diameter 700 μm). In conclusion, high field T1w MRI without contrast may improve the detection limit of small brain metastases, allowing for earlier diagnosis of patients, although the smallest lesions detected with T1w MRI were permeable only to d-luciferin and the amphipathic small molecule (18)F-FLT. Different-sized MR and PET contrast agents demonstrated the gradual increase in leakiness of the blood tumor barrier during metastatic progression, which could guide clinicians in choosing tailored treatment strategies.

Abstract A39: Multimodal imaging of blood-brain barrier disruption during brain metastatic progression in a relevant experimental mouse model

Introduction: Efficient drug delivery to brain metastases is difficult due to an often intact blood-brain barrier (BBB) around smaller lesions, and very few therapeutic drugs penetrate an intact BBB. Relevant experimental brain metastatic models are needed to study biological mechanisms and therapeutic responses of early brain lesions in relation to the BBB. Previous studies injecting small molecules such as sodium fluorescein (MW 376D) have indicated that the BBB is disrupted in experimental brain metastasis larger than 0.25 mm (1). However, little is known regarding at which time point in experimental brain metastasis development the BBB is disrupted, and to what extent larger sized molecules at that time are able to penetrate tumor tissue. We addressed these issues by performing multimodal imaging studies, after injecting contrast agents of various sizes into an established melanoma brain metastasis model (2, 3).

Materials and Methods: All studies were approved by the UCD Animal Care and Use Committee. As in (3), we injected 5X105 human melanoma brain metastasis cells harboring the Luciferase and GFP genes, intracardially into 32 NOD/SCID mice. All animals were followed by bioluminescence imaging (BLI) weekly for 6 weeks. MRI (Bruker Biospec 70/30, RARE sequence, RARE factor=2, TE/TR/ST=9 ms/750 ms/1mm, FOV=2x2 cm, Matrix=256x256, NA=4) was performed at weeks 3, 4, 5 and 6 after tumor cell inoculation, before and after i.v. injections of either Gd-HPDO3A (Prohance, MW 559D, 0.5 μmol/g, 20 mice) or a newly synthetized Gadolinium contrast agent with 3 Gd(III) chelates, termed C3, (MW 2kD, 0.167 μmol/g, 5 mice). 64Cu-Albumin (MW 66.5kD) and 18F-FLT (MW 244D) was also injected i.v. prior to PET imaging at weeks 4 and 6.

Results and Discussion: BLI visualized tumor cell spread in all animal brains 15mins after injections, and a gradual increase in tumor burden between weeks 1 to 6. T1w MRI at week 3 did not show any tumors, however BLI confirmed presence of metastasis. MRI detected tumors at week 4, and the mean, total number of tumors increased from 26 tumors at week 4, to 89 tumors at week 6. There was an exponential increase in tumor burden from week 4 to 6. The number of leaky tumors also increased exponentially, with mean diameters increasing from around 600 μm to around 700 μm. The smallest leaky tumors detectable by MRI were ~200 μm (week 5). The number of non-leaky tumors peaked at 5 weeks, and their mean diameters increased from 260 μm to 450 μm. Metastatic tumor cell proliferation was shown by 18F-FLT, which accumulated in the animal brains at weeks 4 and 6. 64Cu-Albumin PET also showed leakage of albumin into the metastatic lesions at week 6.

Conclusions: Our study shows that T1w 7T MRI can detect leaky brain metastases down to ~200 μm in diameter. Molecules up to 2kD in size may penetrate brain tumor tissue early in tumor development. Our PET study indicates that larger molecules such as albumin may leak out of the metastatic lesions later in tumor development.

References

(1) Fidler IJ et al. Lancet Oncol 3:53-57, 2002.

(2) Sundstrøm T et al, Cancer Res 2012 (In Press).

(3) Wang J et al. Neuropathol Appl Neurobiol 37:189-205, 2011.

Citation Format: Frits Thorsen, Brett Fite, Lisa Mahakian, Victoria Harrison, Sarah Johnson, Elizabeth Ingham, Shengping Qin, Jai W. Seo, Thomas Meade, Terje Sundstrøm, Katherine W. Ferrara. Multimodal imaging of blood-brain barrier disruption during brain metastatic progression in a relevant experimental mouse model. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A39.

A novel nonsense CDK5RAP2 mutation in a Somali child with primary microcephaly and sensorineural hearing loss

Primary microcephaly is a genetically heterogeneous condition characterized by reduced head circumference (-3 SDS or more) and mild-to-moderate learning disability. Here, we describe clinical and molecular investigations of a microcephalic child with sensorineural hearing loss. Although consanguinity was unreported initially, detection of 13.7 Mb of copy neutral loss of heterozygosity (cnLOH) on chromosome 9 implicated the CDK5RAP2 gene. Targeted sequencing identified a homozygous E234X mutation, only the third mutation to be described in CDK5RAP2, the first in an individual of non-Pakistani descent. Sensorineural hearing loss is not generally considered to be consistent with autosomal recessive microcephaly and therefore it seems likely that the deafness in this individual is caused by the co-occurrence of a further gene mutation, independent of CDK5RAP2. Nevertheless, further detailed clinical descriptions of rare CDK5RAP2 patients, including hearing assessments will be needed to resolve fully the phenotypic range associated with mutations in this gene. This study also highlights the utility of SNP-array testing to guide disease gene identification where an autosomal recessive condition is plausible.

Stroke rehabilitation: strategies to enhance motor recovery

Recent evidence indicates that the brain can remodel after stroke, primarily through synaptogenesis. Task-specific and repetitive exercise appear to be key factors in promoting synaptogenesis and are central elements in rehabilitation of motor weakness following stroke. Expert medical management ensures a patient is well enough to participate in rehabilitation with minimal distractions due to pain or depression. Contraint-induced motor therapy and body-weight-supported ambulation are forms of exercise that "force use" of an impaired upper extremity. Technologies now in common use include robotics, functional electrical stimulation, and, to a lesser degree, transcranial magnetic stimulation and virtual reality. The data on pharmacological interventions are mixed but encouraging; it is hoped such treatments will directly stimulate brain tissue to recovery. Mitigation of factors preventing movement, such as spasticity, might also play a role. Research evaluating these motor recovery strategies finds them generally good at the movement level but somewhat less robust when looking at functional performance. It remains unclear whether inconsistent evidence for functional improvement is a matter of poor treatment efficacy or insensitive outcome measures.

An evaluation of the recording of folic acid use in the South West Congenital Anomaly Register

OBJECTIVE

Some congenital anomaly registers are collecting data on risk factors for pregnancies affected by anomalies; yet the quality of that information is rarely assessed. We assessed the quality of the risk factor data in the South West Congenital Anomaly Register (SWCAR) through a review of the data held on folic acid use, in cases of neural tube defect (NTD).

METHODS

We reviewed all cases of NTD reported to SWCAR over 2 years and compared information held in the register with that in handwritten and computerised prenatal records, where available.

RESULTS

Data on folic acid use was recorded in only 41 (36.9%) of the prenatal records of the 111 cases of NTDs reviewed. Information on any folic acid use in the prenatal records was transferred to the register in all instances where it existed. Information on the time of taking folic acid or not taking folic acid was rarely recorded in prenatal records.

CONCLUSION

Incomplete recording of folic acid use and timing in prenatal records has limited the ability of SWCAR to collect accurate information on folic acid use in cases of NTDs. Minimal recording information on folic acid use in prenatal records is suggested.

Malaria-specific antibody responses and parasite persistence after infection of mice with Plasmodium chabaudi chabaudi

While it is known that antibodies are critical for clearance of malaria infections, it is not clear whether adequate antibody responses are maintained and what effect chronic infection has on this response. Here we show that mice with low-grade chronic primary infections of Plasmodium chabaudi or infections very recently eliminated have reduced second infections when compared with the second infection of parasite-free mice. We also show that parasite-specific antibody responses induced by infection of mice with Plasmodium chabaudi contain both short- and long-lived components as well as memory B cells responsible for a faster antibody response during re-infection. Furthermore, parasite-specific antibodies to the C-terminal fragment of merozoite surface protein-1 (MSP-1) undergo avidity maturation. However, antibodies with both low and high avidity persist throughout infection and after re-infection, suggesting repeated rounds of activation and maturation of memory B cells. Neither the avidity profile of the antibody response, nor its maintenance is affected by persisting live parasites. Therefore, differences in parasitemia in re-infection cannot be explained solely by higher levels of antibody or greater affinity maturation of malaria-specific antibodies. These data suggest that there may be an antibody-independent component to the early control of secondary infections in mice that are chronically infected.

Magnesium supplementation and perinatal hypoxia: outcome of a parallel group randomised trial in pregnancy

OBJECTIVE

To determine the effects of magnesium supplementation in pregnancy on the incidence of hypoxic-ischaemic encephalopathy (HIE).

DESIGN

A randomised double-blind placebo-controlled study.

SETTING

A Midwife Obstetric Unit and its two referral hospitals in Cape Town, South Africa.

POPULATION

A group of 4494 black pregnant women of low socio-economic status.

METHOD

Mothers, from the time of booking until delivery, were randomised to receive two identical tablets daily, containing either 128 mg slow-release magnesium stearate or lactose sugar.

MAIN OUTCOME MEASURES

Primary: The incidence of HIE. Secondary: The incidence of fetal heart rate decelerations, term Stillbirths, Low Apgar Scores, Meconium Aspiration Pneumonia.

RESULTS

The incidence of HIE (0.9%) was considerably less than anticipated (2%). There were 22 infants in the placebo group and 15 infants in the supplemented group (P = 0.279). The difference was not significant. Secondary outcomes such as late fetal heart rate decelerations (P = 0.002) and term stillbirths (P = 0.016) were reduced significantly in the supplemented group, but this finding needs further substantiation.

CONCLUSIONS

Magnesium supplementation did not reduce the incidence of HIE significantly, probably because the study was underpowered and compliance was relatively poor.

The nursery needs discoveries

Neonatologists need to readdress the factors that influenced past discoveries

Stress reactivity and family relationships in the development and treatment of endometriosis

OBJECTIVE

To examine stress physiology and facts of family functioning associated with development and course of endometriosis symptoms.

DESIGN

Clinical case data and literature review.

SETTING

Private practice in hospital-affiliated medical office.

PATIENT(S)

One woman with endometriosis, her parents, and a nonsymptomatic volunteer.

INTERVENTION(S)

Measures of physiologic and neural reactivity with biofeedback and neurofeedback equipment during family history interview and while sitting quietly.

MAIN OUTCOME MEASURE(S)

Electroencephalography (EEG), digital skin temperature (DST), electrodermal response (EDR), and electromyography (EMG); facts of family history; contact with family.

RESULT(S)

Endometriosis symptoms were associated with DST, EDR, EMG, and EEG measures indicating prolonged stress reactions for the symptomatic woman and her parents. Facts of family history and relationships for three generations set the stage for stress reactions. Striking differences are evident in the physiology, family history, and contact with family of the nonsymptomatic woman.

CONCLUSION(S)

Differences warrant further study, a larger sample, and additional measures using hormone assay to establish connections between stress reactions in the family, endometriosis symptoms, and response to treatment. Further research will document changes in physiology and in symptoms that accompany interruption of stress reactions with self-regulation training and family systems psychotherapy.

The Cognitive and Social Development of the Child

The social and psychological development of children from birth to adolescence is described using the framework of Jean Piaget's theory of cognitive development. This theory proposes that children's understanding of the world proceeds through four broad stages, with each stage demonstrating an increasingly sophisticated understanding of concepts and how they can be used. The relevance of this development for children's understanding of oral health, disease and dental care is discussed.

Effect of two breathing exercises (Buteyko and pranayama) in asthma: a randomised controlled trial

BACKGROUND

Patients with asthma are interested in the use of breathing exercises but their role is uncertain. The effects of the Buteyko breathing technique, a device which mimics pranayama (a yoga breathing technique), and a dummy pranayama device on bronchial responsiveness and symptoms were compared over 6 months in a parallel group study.

METHODS

Ninety patients with asthma taking an inhaled corticosteroid were randomised after a 2 week run in period to Eucapnic Buteyko breathing, use of a Pink City Lung Exerciser (PCLE) to mimic pranayama, or a PCLE placebo device. Subjects practised the techniques at home twice daily for 6 months followed by an optional steroid reduction phase. Primary outcome measures were symptom scores and change in the dose of methacholine provoking a 20% fall in FEV(1) (PD(20)) during the first 6 months.

RESULTS

Sixty nine patients (78%) completed the study. There was no significant difference in PD(20) between the three groups at 3 or 6 months. Symptoms remained relatively stable in the PCLE and placebo groups but were reduced in the Buteyko group. Median change in symptom scores at 6 months was 0 (interquartile range -1 to 1) in the placebo group, -1 (-2 to 0.75) in the PCLE group, and -3 (-4 to 0) in the Buteyko group (p=0.003 for difference between groups). Bronchodilator use was reduced in the Buteyko group by two puffs/day at 6 months; there was no change in the other two groups (p=0.005). No difference was seen between the groups in FEV(1), exacerbations, or ability to reduce inhaled corticosteroids.

CONCLUSION

The Buteyko breathing technique can improve symptoms and reduce bronchodilator use but does not appear to change bronchial responsiveness or lung function in patients with asthma. No benefit was shown for the Pink City Lung Exerciser.

Anaesthesia for liver transplantation in a patient with methylmalonic acidaemia

Liver transplantation is an accepted modality of treatment in some patients with inborn errors of metabolism. We present a child with methylmalonic acidaemia who had successful liver transplantation. The pathophysiology, medical and anaesthetic managements are discussed.

Responses of seventh grade students to "do you have a partner with whom you would like to have a baby?"

This study investigated differences in demographic data, self-esteem, and coping skills for 225 students in Grade 7 who reported having a partner with whom they wanted to have a baby and 946 students who did not. Data were collected on the Rosenberg Self-esteem Scale, the Family Crisis-oriented Personal Evaluation Scale, and questions related to attitudes towards teen pregnancy and demographic data. The sample included 548 (46.8%) boys and 624 (53.2%) girls whose mean age was 13.2 yr. Students with a partner had significantly lower scores on the curriculum questions, self-esteem, and family coping skills, combined with higher scores in passivity. They indicated a desire to have a greater number of children, beginning by having their first child at a younger age and believed that having a baby improves a couple's relationship. Possible approaches may include effective teaching methods to overcome passivity through boosting self-confidence, goal-setting, and acquiring a purpose in life besides parenting a child.

Induced brain hypothermia in asphyxiated human newborn infants: a retrospective chart analysis of physiological and adverse effects

OBJECTIVE

To assess the physiological effects and adverse side-effects of induced hypothermia in asphyxiated newborn infants as a base for future controlled, randomized trials.

DESIGN

Retrospective chart analysis with historical controls.

SETTING

Tertiary neonatal intensive care unit of the University of Cape Town, South Africa.

PATIENTS

Twenty-one asphyxiated newborns treated with induced hypothermia between September 1997 and February 1998 were compared to 15 asphyxiated newborn infants admitted during March to August 1997. The two groups of infants did not differ in patient characteristics or severity of asphyxia (comparison group vs hypothermia group: Apgar at 5 min 5.3 +/- 3.1 vs 5.2 +/- 2.3; base deficit 15.6 +/- 6.3 vs 11.5 +/- 7.2 and Thompson neurological score 10.1 +/- 4.0 vs 9.1 +/- 3.6).

INTERVENTIONS

Hypothermia was induced by placing a cap formed from coolpacks, at a temperature of about 10 degrees C, around the head of asphyxiated newborn infants to maintain the nasopharyngeal temperature between 34 and 35 degrees C. Hypothermia was maintained for 3 days.

MEASUREMENTS AND RESULTS

In the comparison group 4/15 infants died and in the hypothermia group 4/21 died. Hypothermia was induced at a median of 6.0 h (range 45 min to 53 h) post-partum, maintained for an average of 80 h (median 77.5 h, range 22 to 185 h) and resulted in an average nasopharyngeal temperature of 34.6 +/- 0.5 degrees C. Hypothermia reduced abdominal skin temperature from 36.3 +/- 0.5 degrees C to 35.1 +/- 0.35 degrees C (p = 0.0001), heart rate from 139 +/- 21 to 121 +/- 13 beats/min (p < 0.0001) and respiratory rate from 67 +/- 11 to 56 +/- 9 breaths/min (p = 0.005). Neither episodes of bradycardia nor dysrhythmias, apnea, clinical signs of bleeding diathesis in the hypothermia group nor differences in the frequency of hypoglycaemia and urinary output, blood in urine or tracheal secretion between the two groups were observed. In the survivors the neurological score, assessed at day 2 and day 5, fell from 10.9 +/- 3.5 to 8.1 +/- 4.5 in the hypothermia group and rose from 8.1 +/- 2. 5 to 9.0 +/- 3.1 in the comparison group (p = 0.003).

CONCLUSIONS

Adverse effects of mild hypothermia induced for 3 days in asphyxiated newborns were significantly less than expected from previous reports on neonates with accidental hypothermia.

Relation of endometriosis and neuromuscular disease of the gastrointestinal tract: new insights

OBJECTIVE

To investigate the neuromuscular activity of the gastrointestinal tract by antroduodenal manometry in women with endometriosis documented by laparoscopy, to assess the effects of diet and drug therapy on symptoms, and to assess the bacterial overgrowth that is commonly associated with these nerve diseases.

DESIGN

Prospective, open-label study.

SETTING

A clinical center for the care of women's health.

PATIENT(S)

Fifty women with endometriosis documented by laparoscopy and gastrointestinal tract symptoms characterized by chronic abdominal pain, nausea, vomiting, early satiety, bloating and distention, and altered bowel habits.

INTERVENTION(S)

Motility of the gastrointestinal tract was recorded and bacterial overgrowth was assessed. Treatment consisted of dietary changes, including reduction of glycemic carbohydrates, balancing with omega 9 oils, elimination of foods with caffeine and tyramine, and addition of omega 3 fatty acids, as well as drug therapy with clonazepam (0.25 mg 3 times per day).

RESULT(S)

All 50 women showed a characteristic motility change (ampulla of Vater-duodenal wall spasm, a seizure equivalent of the enteric nervous system). Forty of the women showed bacterial overgrowth. There was a significant reduction in the total symptom score after 8 weeks of treatment.

CONCLUSION(S)

This study suggests that endometriosis and gastrointestinal tract symptoms are a result of the dysfunction of hollow organs. Correction of the biochemical imbalance of the eicosanoid system and the hypersecretion of insulin that results from excessive intake of glycemic carbohydrates and lack of essential fatty acids significantly decreases symptoms in patients with endometriosis and associated neuromuscular disease of the gastrointestinal tract.

Red blood cell magnesium and hypoxic-ischaemic encephalopathy

In developing countries, birth asphyxia is frequently associated with hypoxic ischaemic encephalopathy. This has been attributed to inadequate obstetric care but poor nutrition may also be important. This study determines the association between magnesium stores and hypoxic ischaemic encephalopathy. The level of red blood cell magnesium was measured on 572 women in labour and on selected offspring in a teaching hospital in South Africa. Fifty five of the 572 women delivered infants with hypoxic ischaemic encephalopathy and had significantly lower red blood cell magnesium levels (1.40 mmol/l) than controls. In the latter the levels varied somewhat with the mode of delivery, vertex births 1.76 mmol/l, Caesarean sections 1.67 mmol/l and vacuum extractions 1.61 mmol/l. Infants with hypoxic ischaemic encephalopathy had a significantly lower red blood cell magnesium level (1.39 mmol/l) than normal infants (1.61 mmol/l). Fifty four of 55 babies were black and from poor social circumstances and nutritional deficiency may be relevant. Maternal height, age and the duration of labour did not influence the chance of hypoxic ischaemic encephalopathy and affected infants were more likely than normal ones to be meconium stained (50%), to have a low Apgar score (58%) and to need endotracheal intubation at birth (54%). An intervention study in early pregnancy may determine magnesium's role in hypoxic ischaemic encephalopathy associated with asphyxia.

In vivo adaptation of bicarbonate reabsorption by rat distal tubules during acid loading

We carried out in vivo microperfusion experiments in acid-loaded rats to characterize the adaptive response of the unidirectional components secretory flux (Jsec) and reabsorptive flux (Jreab)] of distal tubule bicarbonate reabsorption and to test the hypothesis that Jreab is dependent on bafilomycin A1-sensitive H(+)-adenosinetriphosphatase activity. During 18 h of severe acidosis there was a significant decrease in Jsec (-15 +/- 3 vs. -38 +/- 5 pmol.min-1.mm-1, P < 0.05) and a significant increase in Jreab (37 +/- 6 vs. 0 +/- 5 pmol.min-1.mm-1, P < 0.05), which was insensitive to 10(-5) M bafilomycin A1, 10(-5) M Sch-28080, and 3 mM amiloride. After 3 days of acid loading, these same inhibitors reduced Jreab by approximately 60%. However, when water flux was completely inhibited by isosmotic perfusion, a significant Jreab (15 +/- 2 pmol.min-1.mm-1) resistant to 10(-5) M bafilomycin A1 persisted, as in severe acidosis. In reabsorbing distal tubules of overnight-fasted rats, Sch-28080 elicited no inhibition, whereas bafilomycin A1 and amiloride had significant effects (28 +/- 5, 24 +/- 4, respectively, vs. 50 +/- 4 pmol.min-1.mm-1 for fasted rats, P < 0.05). Thus, although Jsec is reduced in the transition from mild to severe metabolic acidosis of 18-h duration, the predominant effect is a stimulation of bafilomycin A1-resistant Jreab.

In vivo modulation of rat distal tubule net HCO3 flux by VIP, isoproterenol, angiotensin II, and ADH

To examine the in vivo effects of agonists reported to influence bicarbonate flux (JtCO2), microperfusion experiments were carried out on distal tubules of normally fed or overnight-fasted rats. As we previously reported, distal tubules from fed rats reabsorbed no bicarbonate, whereas overnight-fasted rats consistently reabsorbed bicarbonate (JtCO2 10 +/- 3 pmol.min-1.mm-1; P < 0.01). Vasoactive intestinal peptide and isoproterenol infused intravenously (7.3 and 4.0 micrograms.kg-1.h-1, respectively) in fasted rats suppressed JtCO2 and, in the case of vasoactive intestinal peptide, elicited net bicarbonate secretion (JtCO2 -10 +/- 2 and -4 +/- 4 pmol.min-1.mm-1, respectively). In fed rats, angiotensin II infused at a rate of 1.2 micrograms.kg-1.h-1 stimulated bicarbonate reabsorption (JtCO2 16 +/- 3 pmol.min-1.mm-1), while antidiuretic hormone infused at 0.024 micrograms.kg-1.h-1 elicited a similar response (17 +/- 4 pmol.min-1.mm-1), both values being significantly different from control. These results, therefore, demonstrate for the first time that these agonists can modulate JtCO2 at the distal tubule site in vivo and therefore may be potential regulators of systemic acid-base balance.

Distal tubule unidirectional HCO3 reabsorption in vivo during acute and chronic metabolic alkalosis in the rat

During metabolic alkalosis (MA) associated with 2 days of dietary chloride restriction, there is net bicarbonate secretion by rat distal tubules in vivo, whereas after 5 wk of chloride depletion alkalosis there is net bicarbonate reabsorption. To examine unidirectional components of net bicarbonate reabsorption during chronic MA, we measured distal tubule unidirectional bicarbonate secretion (Jsec) and reabsorption (Jreab), as well as the inhibitor sensitivity of Jreab. In control, 2-day, and 7-day alkalosis, Jsec was similar. Jreab, however, was only present in 7-day MA (17 +/- 3 pmol.min-1.mm-1, P < 0.05). This Jreab was completely suppressed by perfusion with 10(-7) M bafilomycin A1, partially suppressed with 10(-5) M Schering (Sch)-28080 (4 +/- 2 pmol.min-1.mm-1, P < 0.1), and converted into a secretory flux by 3 mM amiloride. We conclude that adaptation to chloride depletion MA from the acute secretory phase to the chronic state, where plasma bicarbonate is sustained at elevated levels, does not involve suppression of distal tubule Jsec but rather enhanced Jreab, which is sensitive to bafilomycin, Sch-28080, and amiloride.

Pneumocystis carinii pneumonia: detection of parasites by immunofluorescence based on a monoclonal antibody

A monoclonal antibody-based immunofluorescence test for the detection of Pneumocystis carinii was evaluated in comparison with the conventional direct staining by Grocott's silver methenamine technique. A total of 254 respiratory samples from HIV positive and other immunocompromised patients were examined. Cysts were detected in 30 (12%) of samples using the monoclonal test, but only 15 (6%) positives were found using the Grocott method. There is need for a speedy and efficient test for detection of these organisms, and the monoclonal test was found to be more reliable, quicker and more sensitive than the Grocott technique.

Bicarbonate secretion in vivo by rat distal tubules during alkalosis induced by dietary chloride restriction and alkali loading

To examine in vivo the separate effects on distal tubule JtCO2, of dietary chloride restriction, bicarbonate loading, and changes in luminal chloride concentration, we microperfused distal tubules at a physiologic flow rate (8 nl/min) with solutions containing either 45 or 0 mM chloride (after gluconate substitution). Rats were fed a diet containing zero, minimal, or normal amounts of chloride, while drinking either water or a solution of 0.15 M sodium bicarbonate. Neither extracellular fluid volume contraction nor negative chloride balance ensued. Analysis of covariance with repeated measures demonstrated that dietary chloride, drinking sodium bicarbonate, and perfusion with either 45 mM or zero chloride, each have separate and significant modulating effects on distal tubule bicarbonate secretion. During mild alkalemia, there is modest bicarbonate secretion which is significantly different from zero (-9.9 +/- 3.2 pmol.min-1.mm-1, P less than 0.01), and which is suppressed after perfusion with zero chloride. In contrast, during more pronounced metabolic alkalosis after supplemental bicarbonate drinking, the bicarbonate secretory flux is brisk (-26 +/- 3 pmol.min-1.mm-1) and significantly different from zero and persists (-11 +/- 3 pmol.min-1.mm-1) even during perfusion with zero luminal chloride. Accordingly, in this two-day model of alkalosis induced by dietary chloride restriction, there is regulatory secretion of bicarbonate by distal tubules in vivo which is modulated by luminal chloride concentration.

Histological demonstration and frequency of intrahepatocytic copper in patients suffering from alcoholic liver disease

This study was carried out to determine whether stainable copper accumulates in the hepatocytes of patients with alcoholic liver disease. Liver sections from 44 cases of alcoholic cirrhosis and 32 cases of non-cirrhotic alcoholic liver disease were stained by the rubeanic acid, rhodanine and orcein methods. Intrahepatocytic copper granules were found in 13 cases of cirrhosis (30%), but in none of the non-cirrhotic livers. The abundance of granules did not appear to be related either to the activity of the cirrhotic process or to the presence of cholestasis. It may well be that alcoholic cirrhosis is the most common disease associated with excess of intrahepatocytic copper.