Keratinocyte EGF signaling dominates in Atopic Dermatitis lesions: a comparative RNAseq analysis

Atopic dermatitis (AD) remains a highly heterogenous disorder with a multifactorial aetiology. Whilst keratinocytes are known to play a fundamental role in AD, their contribution to the overall immune landscape in moderate‐to‐severe AD is still poorly understood. In order to design new therapeutics, further investigation is needed into common disease pathways at the molecular level. We used publicly available whole‐tissue RNAseq data (4 studies) and single‐cell RNAseq keratinocyte data to identify genes/pathways that are involved in keratinocyte responses in AD and after dupilumab treatment. Transcripts present in both keratinocytes (single‐cell) and whole‐tissue, referred to as the keratinocyte‐enriched lesional skin (KELS) genes, were analysed using functional/pathway analysis. Following statistical testing, 2049 genes (16.8%) were differentially expressed in KELS. Enrichment analyses predicted increases in not only type‐1/type‐2 immune signalling and chemoattraction, but also in EGF‐dominated growth factor signalling. We identified complex crosstalk between keratinocytes and immune cells involving a dominant EGF family signature which converges on keratinocytes with potential immunomodulatory and chemotaxis‐promoting consequences. Although keratinocytes express the IL4R, we observed no change in EGF signalling in KELS after three‐month treatment with dupilumab, indicating that this pathway is not modulated by dupilumab immunotherapy. EGF family signalling is significantly dysregulated in AD lesions but is not associated with keratinocyte proliferation. EGF signalling pathways in AD require further study.

Splenic Capture and In Vivo Intracellular Biodegradation of Biological-Grade Graphene Oxide Sheets

Carbon nanomaterials, including 2D graphene-based materials, have shown promising applicability to drug delivery, tissue engineering, diagnostics, and various other biomedical areas. However, to exploit the benefits of these materials in some of the areas mentioned, it is necessary to understand their possible toxicological implications and long-term fate in vivo. We previously demonstrated that following intravenous administration, 2D graphene oxide (GO) nanosheets were largely excreted via the kidneys; however, a small but significant portion of the material was sequestered in the spleen. Herein, we interrogate the potential consequences of this accumulation and the fate of the spleen-residing GO over a period of nine months. We show that our thoroughly characterized GO materials are not associated with any detectable pathological consequences in the spleen. Using confocal Raman mapping of tissue sections, we determine the sub-organ biodistribution of GO at various time points after administration. The cells largely responsible for taking up the material are confirmed using immunohistochemistry coupled with Raman spectroscopy, and transmission electron microscopy (TEM). This combination of techniques identified cells of the splenic marginal zone as the main site of GO bioaccumulation. In addition, through analyses using both bright-field TEM coupled with electron diffraction and Raman spectroscopy, we reveal direct evidence of in vivo intracellular biodegradation of GO sheets with ultrastructural precision. This work offers critical information about biological processing and degradation of thin GO sheets by normal mammalian tissue, indicating that further development and exploitation of GO in biomedicine would be possible.

Enteroendocrine cells in terminal ileal Crohn's disease

BACKGROUND AND AIMS

Enteroendocrine cells sense gut luminal contents, and orchestrate digestive physiology whilst contributing to mucosal homeostasis and innate immunity. The terminal ileum is the key site of EEC expression but detailed assessment of their subtypes, lineage transcription factors and expression products has not been undertaken in terminal ileal Crohn's disease. Recent Crohn's disease gene wide association studies have linked the neuroendocrine transcription factor Phox2b; while autoantibodies to an enteroendocrine protein, ubiquitination protein 4a, have been identified as a disease behaviour biomarker.

METHODS

Terminal ileal tissue from small or large bowel Crohn's disease and normal controls was analysed for enteroendocrine marker expression by immunohistochemistry and quantitative polymerase chain reaction. Inflammation was graded by endoscopic, clinical, histological and biochemical scoring.

RESULTS

In small bowel disease, glucagon-like peptide 1 and chromogranin A cells were increased 2.5-fold (p=0.049) and 2-fold (p=0.031) respectively. Polypeptide YY cells were unchanged. Ileal enteroendocrine cell expression was unaffected in the presence of Crohn's colitis. Phox2b was co-localised to enteroendocrine cells and showed a 1.5-fold increase in ileal disease. Significant mRNA increases were noted for chromogranin A (3.3-fold; p=0.009), glucagon-like peptide 1 (3.1-fold; p=0.007) and ubiquitination protein 4a (2.2-fold; p=0.02). Neurogenin 3, an enteroendocrine transcription factor showed ~2 fold-upregulation (p=0.048).

CONCLUSIONS

Enhanced enteroendocrine cell activity is present in small bowel disease, and observed in restricted cell lineages. This may impact on the epithelial immune response, cellular homeostasis and nutrient handling and influence appetite via increased satiety signalling in the gut-brain axis.

Cardiovascular disease mortality among First Nations people in Canada, 1991-2001

OBJECTIVE

To compare cardiovascular disease mortality patterns between First Nations people and non-Aboriginal adults by sex and by income adequacy quintile and level of educational attainment.

METHODS

A 15% sample of 1991 Canadian census respondents aged 25 years or older was previously linked to 11 years of mortality data. In this study, First Nations people were defined by North American Indian ethnic origin (ancestry), registration under the Indian Act, and/or membership in an Indian band or First Nation. The cohort included 62 400 First Nations people and 2 624 300 non-Aboriginal people.

RESULTS

Compared to non-Aboriginal cohort members, the age-standardized cardiovascular disease mortality rate was 30% higher for First Nations men and 76% higher for First Nations women. This represented an excess of 58 deaths and 71 deaths per 100 000 person-years at risk, for First Nations men and women, respectively. Within each income adequacy quintile (adjusted for family size and region of residence) and level of educational attainment, the risk of dying from cardiovascular disease was higher for First Nations people compared to their non-Aboriginal counterparts.

CONCLUSION

First Nations people had higher rates of death from cardiovascular disease than non-Aboriginal Canadians within each income quintile and level of education. Income and education accounted for 67% and 25% of the excess mortality of First Nations men and women respectively.

Cardiovascular disease mortality among First Nations people in Canada, 1991–2001

Objective

To compare cardiovascular disease mortality patterns between First Nations people and non-Aboriginal adults by sex and by income adequacy quintile and level of educational attainment.

Methods

A 15% sample of 1991 Canadian census respondents aged 25 years or older was previously linked to 11 years of mortality data. In this study, First Nations people were defined by North American Indian ethnic origin (ancestry), registration under the Indian Act, and/or membership in an Indian band or First Nation. The cohort included 62 400 First Nations people and 2 624 300 non-Aboriginal people.

Results

Compared to non-Aboriginal cohort members, the age-standardized cardiovascular disease mortality rate was 30% higher for First Nations men and 76% higher for First Nations women. This represented an excess of 58 deaths and 71 deaths per 100 000 person-years at risk, for First Nations men and women, respectively. Within each income adequacy quintile (adjusted for family size and region of residence) and level of educational attainment, the risk of dying from cardiovascular disease was higher for First Nations people compared to their non-Aboriginal counterparts.

Conclusion

First Nations people had higher rates of death from cardiovascular disease than non-Aboriginal Canadians within each income quintile and level of education. Income and education accounted for 67% and 25% of the excess mortality of First Nations men and women respectively.

Influenza H2 haemagglutinin activates B cells via a MyD88-dependent pathway

Influenza viruses are serious respiratory pathogens, responsible for half a million deaths each year. The viral surface haemagglutinin (HA) protein has been shown to be an important determinant of viral pathogenicity. HA is the virion attachment and fusion protein, and the major target for neutralizing antibodies; however, it is also involved in triggering innate responses that may have an important impact on the disease course. We have examined the role of the toll-like receptor (TLR) family in innate responses to influenza virus and influenza HA. TLR7 has recently been found to mediate recognition of influenza RNA. Here, we show for the first time that influenza HA of the H2 subtype induces innate responses in murine B lymphocytes via a MyD88-dependent pathway distinct from that involved in sensing viral RNA. We also show that inactivated influenza virus induces activation of human B cells. Our findings suggest that the molecule mediating these responses may be a novel member of the TLR family.

Brain magnetic resonance imaging abnormalities in merosin-positive congenital muscular dystrophy

We report the brain magnetic resonance imaging (MRI) findings in 23 patients with merosin-positive congenital muscular dystrophy (CMD). Twelve patients had normal scans. Eight other children had essentially normal scans but showed mild non-specific periventricular white matter changes. Three children had structural abnormalities on imaging. The first patient, a 15-month-old boy with hypotonia, muscle weakness and global development delay, had moderate cerebellar atrophy and mild dilatation of the lateral ventricles. The second child, a 3-year-old ambulant girl with subtle learning problems, had mild cerebellar hypoplasia and a large subarachnoid space when scanned at 16 months. The third patient, a 15-year-old ambulant male with normal intelligence and complex partial seizures, had polymicrogyria of both temporoparietal lobes on brain MRI. The clinical features and motor ability of children with merosin-positive CMD are variable, although usually milder than merosin-deficient CMD. Our findings confirm that central nervous system involvement can occur in some merosin-positive cases. We suggest performing brain MRI in children with merosin-positive CMD, as this may help in our understanding of this very heterogeneous disease.

Merosin-deficient congenital muscular dystrophy: the spectrum of brain involvement on magnetic resonance imaging

Children with merosin-deficient congenital muscular dystrophy (CMD) have striking white matter changes on T-2 weighted brain magnetic resonance imaging (MRI). There have been occasional cases with structural abnormalities, mainly involving the occipital cortex. We report our brain imaging findings in 14 children with merosin-deficient CMD. Ten cases had a severe reduction or absence of merosin on immunocytochemistry and four cases had partial reduction. All 14 cases had white matter changes, which appeared after the first 6 months of life and persisted with time. The changes were diffuse and the oldest child scanned (14 years) also showed involvement of the U fibres. Five children with total absence of merosin also had structural abnormalities. One child had moderate mental retardation and epilepsy, mainly characterised by complex partial seizures, with atypical absences, which had been difficult to treat. Brain MRI showed marked occipital agyria and pontocerebellar hypoplasia. The gyral pattern of the rest of the brain looked normal. The four other cases, all with normal intelligence, also had cerebellar hypoplasia with variable involvement of the pons. They did not, however, have neuronal migration defects. It is recognised that several forms of congenital muscular dystrophy, namely Fukuyama CMD, muscle-eye-brain disease and Walker-Warburg syndrome, have structural brain abnormalities and associated severe mental retardation. Our cases demonstrate that a range of structural malformations can also be found in a significant number of children with merosin-deficient CMD.

Early prognostic indicators of outcome in infants with neonatal cerebral infarction: a clinical, electroencephalogram, and magnetic resonance imaging study

OBJECTIVE

The aim of this study was to identify prognostic factors in newborns with cerebral infarction.

DESIGN

Antenatal and perinatal factors and early clinical, electroencephalogram (EEG), and magnetic resonance imaging (MRI) findings were compared with neurodevelopmental outcome in 24 children with evidence of cerebral infarction on neonatal MRI.

RESULTS

Out of 24 infants, 19 had an infarction in the territory of a major cerebral vessel and 5 in the borderzone between cerebral arteries. Neuromotor outcome was normal in 17 and abnormal in 7 infants. Of these 7 infants, 5 infants showed a definite hemiplegia, whereas the other 2 showed some asymmetry of tone or function but no definite hemiplegia. None of the adverse antenatal or perinatal factors was significantly associated with abnormal outcome. Neonatal clinical examination was also not always predictive of the outcome. The extent of the lesion on MRI was a better predictor. In particular, it was the concomitant involvement of hemisphere, internal capsule and basal ganglia that was always associated with an abnormal outcome whereas the involvement of only one or two of the three tended to be associated with a normal outcome. EEG was also very helpful. Abnormal background activity either unilateral or bilateral was found in 6 infants and 5 out of 6 developed hemiplegia. In contrast, the presence of seizure activity in presence of a normal background was not related to abnormal outcome.

CONCLUSIONS

Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia.

Basal ganglia damage and impaired visual function in the newborn infant

AIM

To examine the effects of early lesions in the visual pathway on visual function; and to identify early prognostic indicators of visual abnormalities.

METHODS

The visual function of 37 infants with perinatal brain lesions on magnetic resonance imaging was assessed using behavioural and electrophysiological variables.

RESULTS

Normal visual behaviour was observed in most infants with large bilateral occipital lesions, but all the infants with associated basal ganglia involvement had abnormal visual function. Visual abnormalities were also present in six infants with isolated basal ganglia lesions.

CONCLUSIONS

These observations suggest that basal ganglia may have an integral role in human visual development and that their presence on neonatal MRI could be an early marker of abnormal visual function.

Visual function in full-term infants with hypoxic-ischaemic encephalopathy

Thirty-one full term infants with hypoxic-ischaemic encephalopathy (HIE) were studied with a battery of tests designed to evaluate visual function in infancy and with serial MRI. Their age ranged between 5 and 31 months. The aim of the study was to evaluate whether the degree of HIE or the site and size of lesions on MRI could predict visual outcome. Twenty of the 31 infants studied showed abnormal results on at least one of the visual tests used. While visual function was generally normal in grade I HIE and severely impaired in grade III, visual outcome was variable in grade II. MRI findings were better predictors of visual impairment than the degree of HIE. Normal scans tended to be associated with normal visual function, irrespective of the severity of HIE. All but one of the infants with diffuse hemispheric involvement also showed multiple visual abnormalities. The concomitant involvement of basal ganglia was always associated with more severe visual outcome. These results suggest that infants with generalised lesions secondary to global insults are at high risk of severe visual impairment even in presence of normal acuity and require early assessment of various aspects of visual function.

Evaluation of the corpus callosum in clumsy children born prematurely: a functional and morphological study

The aim of this study was to evaluate the incidence of functional and neuroradiological abnormalities of the corpus callosum in a group of 21 prematurely born children (GA < 34 weeks) who were found to be "clumsy" on the Movement Assessment Battery for Children at 6 years of age. All children underwent functional and morphological assessment of the corpus callosum. The functional assessment included tests of somesthesis, diadochokinesis and repetitive finger tapping. The morphology of the corpus callosum was evaluated on midsagittal MRI. Thirteen of the 21 clumsy children showed morphological abnormalities which were significantly associated with functional abnormalities. Morphological changes of the corpus callosum were also significantly associated with lesions on both neonatal ultrasound and late MRI. Our results support the view that morphological abnormalities of the corpus callosum are frequent in children born prematurely. The association between these abnormalities and lesions on US or MRI suggests that they are likely to be secondary to pre- or perinatal lesions.

Sequential study of central and peripheral nervous system involvement in an infant with merosin-deficient congenital muscular dystrophy

Diffuse white matter changes on brain imaging and peripheral neuropathy are associated features of merosin-deficient congenital muscular dystrophy (CMD). In this report we describe the early manifestation and evolution of brain changes, and the involvement of the peripheral nervous system in a female infant with merosin-deficient CMD diagnosed in the neonatal period who had sequential clinical, neurophysiological and magnetic resonance imaging (MRI) assessment. Both MRI and nerve conduction velocity in the first week of life failed to demonstrate any abnormality. By 6 months of age both nerve conduction and MRI were abnormal. White matter changes became more evident on a further scan at 1 yr of age and this pattern remained unchanged on the following scan performed at 17 months of age. Our findings suggest a failure in the physiological maturation process of myelination of both the central and peripheral nervous system.

Hypoxic-ischaemic encephalopathy: early and late magnetic resonance imaging findings in relation to outcome

Sixteen infants with hypoxic-ischaemic encephalopathy (HIE) were studied using serial magnetic resonance imaging (MRI) up to the age of 2 years. The infants had regular neurological and developmental assessments. An nuclear magnetic resonance (NMR) score was devised to quantify the early and late MRI findings and a neurological optimality score was used to quantify abnormal neurological signs at the time of the final examination. The follow up MRI score was compared with the neonatal MRI score and the outcome of the child. There was a strong positive correlation between the neonatal and follow up MRI scores and between MRI scores and optimality score. All infants with a normal outcome had patchy white matter abnormalities. All infants with an abnormal outcome had extensive white matter abnormalities. The outcome was most severe in those infants with additional basal ganglia atrophy with or without cyst formation. Infants with mild HIE who are developmentally normal at the age of 2 years do not have normal MRI scans and may be at risk of minor neurological problems by school age. Bilateral basal ganglia abnormalities are associated with severe developmental delay, but infants with mainly white matter and cortical abnormalities have less severe problems despite extensive tissue loss.

Visual function and perinatal focal cerebral infarction

AIMS

To evaluate the visual function of infants with perinatal cerebral infarction in whom the site and size of the lesion has been determined using magnetic resonance imaging (MRI).

METHODS

Twelve infants with cerebral infarction on MRI were studied with a battery of tests specifically designed to evaluate visual function in infancy. This included tests: for visual attention (fixation shifts); of cerebral asymmetry (optokinetic nystagmus, visual fields); for assessment of acuity (forced choice preferential looking); and neurophysiological measures of vision (phase reversal and orientation reversal visual evoked potential).

RESULTS

A considerable incidence of abnormalities on at least one of the tests for visual function used was observed. The presence or severity of visual abnormalities could not always be predicted by the site and extent of the lesion seen on imaging.

CONCLUSIONS

Early focal lesions affecting the visual pathway can, to some extent, be compensated for by the immature developing brain. These data suggest that all the infants presenting with focal lesions need to be investigated with a detailed assessment of various aspects of vision.

Trends in mammography and Pap smear utilization in Canada

We have examined trends in the utilization of two preventive health procedures for women in Canada based on our analysis of the 1994 National Population Health Survey (NPHS) and comparisons with two previous large population health surveys. The NPHS provides evidence that Canadian women's use of mammography has continued to increase between 1990 and 1994, while use of Pap smears has remained steady. Increases in mammographic utilization are seen for all age groups and in all provinces of Canada. Women who are less than the recommended age of 50-69 years for screening mammography access these services in considerable numbers. Large proportions of women aged 18-24 and 65 or over have never had a Pap smear, and recency of Pap smear is associated with age. Income adequacy and educational attainment are still strong predictors of which women utilize Pap smears and mammograms. We conclude that the NPHS is sufficiently broad-based to be used in a surveillance program to track Pap smear and mammography utilization.

Ischaemic and haemorrhagic brain lesions in newborns with seizures and normal Apgar scores

Serial ultrasound scans and conventional and diffusion weighted magnetic resonance imaging (MRI) were performed on 16 neonates who presented with seizures. The Apgar scores were normal and subsequently no metabolic or infective cause could be found. The aim of the study was to evaluate the extent to which early sequential imaging can elucidate the cause of seizures in apparently neurologically normal infants. Fourteen of the infants had haemorrhagic or ischaemic lesions on MRI and these were detected by ultrasound scanning in 11. Early ultrasound scanning detected the haemorrhagic lesions but the ischaemic lesions were often not seen until the end of the first week of life. Early MRI, however, was able to detect all the ischaemic lesions. The evolution of the insult could be timed by using serial ultrasound scans and a combination of diffusion weighted and conventional MRI during the first week of life, confirming a perinatal insult even in the absence of fetal distress. Although the aetiology of these lesions remains obscure, serial ultrasound scans will detect the presence of cerebral lesions in neonates presenting with isolated seizures but additional MRI sequences will give better definition on type, site, and extent of the pathology.

Clinical phenotype in congenital muscular dystrophy: correlation with expression of merosin in skeletal muscle

It has recently been shown that merosin, an extracellular matrix protein linked to the dystrophin-associated glycoproteins, is deficient in a proportion of patients with classical congenital muscular dystrophy (CMD). We have undertaken a detailed study of the clinical features and brain imaging in 24 cases of CMD in relation to the merosin status. Immunocytochemistry showed that merosin was present in 13 cases and markedly deficient in 11. In the merosin-positive cases, the maximum motor achievement was independent walking in 11, walking with support in one and sitting unsupported in one (currently 18 months old). In contrast, none of the merosin-deficient cases achieved independent ambulation. Two achieved walking with support, nine standing with support. In addition, nine of the 11 merosin-deficient cases had a creatine kinase level greater than 2000 whereas only one merosin-positive case had this degree of elevation. Magnetic resonance imaging of the brain was carried out on 15 of the children. All eight merosin-positive cases had normal scans whereas all seven of the merosin-deficient cases had significant changes in the white matter. This study has demonstrated that children with merosin-deficient CMD have a more severe clinical phenotype and associated white matter changes on brain imaging.

Minor neurological and perceptuo-motor deficits in children with congenital muscular dystrophy: correlation with brain MRI changes

Diffuse white matter changes on magnetic resonance imaging (MRI) have been a consistent feature in some children with the "pure" form of congenital muscular dystrophy (CMD) in which there are no structural changes in the brain or severe mental retardation. The aim of this study was to assess fine motor and perceptuo-motor abilities in children with CMD with and without MRI changes. Twenty-two children with "pure" CMD were investigated with a standard neurological examination and a battery of tests (Manual dexterity from the Movement ABC, test of visual-motor integration, Zurich Neuromotor test) which have already been used to detect minor neurological signs related to white matter changes. The cohort was then divided in two groups for analysis depending on the presence or the absence of diffuse white matter changes. A significant difference was found for all the tests between the group of the CMD children with normal MRI and the group with diffuse white matter changes. The manual dexterity and the Zurich Neuromotor tests showed a greater sensitivity than the test of visual-motor integration, which had some false negatives. It is of interest that in the group with diffuse white matter changes the presence of contractures or weakness did not seem to affect the quality of the performance; all these children scored abnormally on the test, irrespective of the severity or the extent of contractures and weakness. In contrast, in children with normal MRI severe contractures and weakness did affect the performances. Our results demonstrate that perceptuo-motor difficulties and minor neurological soft signs are a consistent feature in CMD children with diffuse MRI changes but not with normal MRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial concordance of brain magnetic resonance imaging changes in congenital muscular dystrophy

Cerebral white matter changes have been described in a significant number of individual patients with "pure" congenital muscular dystrophy without clinical evidence of central nervous system involvement. The cause for the imaging changes is unknown but it is possible that they are the result of abnormal expression in the brain of the gene also responsible for the muscular dystrophy. In this study magnetic resonance imaging of the brain was performed on seven sibling pairs with congenital muscular dystrophy and normal intelligence to establish whether imaging changes are consistent within families. Diagnosis of congenital muscular dystrophy was based on clinical and muscle biopsy findings. Children from two families had normal scans; the remaining five sibling pairs showed white matter changes and within each family the changes were virtually identical in severity and distribution. Our data indicate that the central nervous system changes are consistent within individual families, suggesting that they probably relate to the mutation in the congenital muscular dystrophy genes involved in the respective families.

Neurological 'soft' signs may identify children with sickle cell disease who are at risk for stroke

Stroke is one of the most frequent complications of sickle cell disease (HbSS), occurring in 7-17% of children. Recent studies recognized more minor lesions on MRI, not associated with clinical signs on standard neurological examination, which however have been found to be a risk factor for developing stroke later. The aim of this study was to evaluate whether minor lesions observed on imaging could be associated with 'soft' neurological signs not detectable on conventional neurological examination. Fourteen children with HbSS were assessed with MRI, standard neurological examination and evaluation of 'soft' signs (Zurich Neuromotor Test) and motor function (Movement ABC). Eight of the 14 children scanned showed lesions on MRI but only 3 of the full cohort were abnormal on standard neurological examination. However, all of the eight children with MRI lesions also showed abnormal signs on at least one of the two tests (Zurich and Movement ABC). All the children with normal MRI were normal on all the tests performed. The sensitivity of Zurich Neuromotor Test and Movement ABC in the group of children with MRI lesions is 0.88 and 0.75, respectively, and increases to 1 when the two tests are used together. The specificity of both tests is 1 even when the tests are used separately.

CONCLUSION

Although the number of cases is small, 'soft' signs may reliably identify the presence of even minor MRI lesions, allow the evaluation of the global incidence of major and minor neurological signs and may also help to identify the population at risk for developing strokes. This population could then be closely monitored and benefit from early intervention.

Somatosensory and visual evoked potentials in congenital muscular dystrophy: correlation with MRI changes and muscle merosin status

Congenital muscular dystrophy comprises a heterogeneous group of disorders, that have in common an early onset and a dystrophic picture on the muscle biopsy. The "pure" form of congenital muscular dystrophy is not associated with severe mental retardation or structural changes in the brain, though white matter changes on brain imaging have been detected in a significant proportion of cases. In this study we evaluated the incidence of sensory abnormalities (somatosensory and visual evoked responses) in a group of 17 patients with "pure" congenital muscular dystrophy and correlated the results of the evoked responses with the presence or absence of white matter changes on brain magnetic resonance imaging. Our results show close correlation between the presence of MRI white matter changes and abnormalities in the sensory evoked potentials. Conversely, all patients with normal brain MRI had normal somatosensory evoked potentials (SEP). Visual evoked potentials were less sensitive than somatosensory evoked potentials in detecting abnormalities in children with white matter changes on MRI. With the recent discovery of deficiency in merosin expression in the skeletal muscle of a subgroup of patients with CMD, we also correlated the presence or absence of white matter changes and the SEP responses with the merosin status. The results indicate that all merosin-negative patients had abnormal SEP as well as abnormal MRI, whilst no patient with normal merosin expression had an abnormal scan or abnormal SEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal neurology, past present and future. A window on the brain

Interest in the neurology of the newborn has been largely stimulated by the new advances of imaging; CT, cranial ultrasonography and MRI which for the first time allowed diagnosis of brain lesions in the live infant which in the past could only be made by post mortem examinations. (Ultrasound in particular, as it is safe, cheap and portable has been eminantly suitable for routine use in the nurseries to study the incidence, timing and evolution of the lesions in the neonatal period. While MRI is expensive and more difficult to perform it gives superb anatomical definition and is also safe for repeated examinations. It is thus very suitable to follow the evolution of the lesions into infancy). The aim of this presentation is to illustrate how an integrated approach with the combined use of imaging and clinical evaluations lead to a better understanding of antenatal and perinatal factors which may be responsible for the production of these lesions on one hand and the impact of these lesions on later development on the other.

Replacement of potassium ions by ammonium ions in different micro-organisms grown in potassium-limited chemostat culture

The biomass concentration extant in potassium-limited cultures of either Klebsiella pneumoniae or Bacillus stearothermophilus (when growing at a fixed temperature and dilution rate in a glucose/ammonium salts medium) increased progressively as the medium pH value was raised step-wise from 7.0 to 8.5. Because the macromolecular composition of the organisms did not vary significantly, this increase in biomass could not be attributed to an accumulation of storage-type polymers but appeared to reflect a pH-dependent decrease in the cells' minimum K+ requirement. Significantly, this effect of pH was not evident with cultures in which no ammonium salts were present and in which either glutamate or nitrate was added as the sole nitrogen source; however, it was again manifest when various concentrations of NH4Cl were added to the glutamate-containing medium. This suggested a functional replacement of K+ by NH4+, a proposition consistent with the close similarity of the ionic radii of the potassium ion (1.33 A) and the ammonium ion (1.43 A). At pH 8.0, and with a medium containing both glutamate (30 mM) and NH4Cl (100 mM), cultures of B. stearothermophilus would grow without added potassium at a maximum rate of 0.7 h-1. Under these conditions the cells contained maximally 0.1% (w/w) potassium (derived from contaminating amounts of this element in the medium constituents), a value which should be compared with one of 1.4% (w/w) for cells growing in a potassium-limited medium containing initially 0.5 mM K+.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteosarcoma and other neoplasms of bone. Magnetic resonance spectroscopy to monitor therapy

Fourteen patients with malignant tumors of bone (ten osteogenic sarcomas, one Ewing's tumor, one giant-cell tumor, two non-Hodgkin's lymphomas), plus one patient with a synovial cell sarcoma, who had been treated by standard extremity-conserving chemotherapy regimens, were examined before treatment by means of localized phosphorus 31 magnetic resonance spectroscopy. Thirteen (86%) of 15 examinations were successful, and 100% of successful examinations showed metabolic abnormality in the tumor. Tumors contained excess adenosine triphosphate and inorganic phosphate, an unusual peak of phosphomonoester, consistent with excessive glycolysis in tumors. The intratumor pH was normal in the 12 bone tumors, but acidic in the single soft-tissue sarcoma (pH 6.8). Metabolic response was observed in all seven patients monitored during chemotherapy, with the earliest examinations being performed two days after first treatment. An increase in the inorganic phosphate level, loss of adenosine triphosphate, and loss of phosphomonoester indicated tumor response; loss of all abnormal metabolites (two of seven patients) indicated regression of the tumor. Tumor relapse was accompanied by reappearance of abnormalities in the magnetic resonance spectrum. Phosphorus 31 magnetic resonance spectroscopy offers a unique means of determining the early response of these malignant tumors to therapy as well as predicting their relapse.

Long-term measurement of skeletal and lean body mass in Paget's disease of bone treated with synthetic human calcitonin

Total body calcium (an index of skeletal mass), ulnar bone density, and total body potassium (lean body mass) were followed for up to 5 years in 38 patients with Paget's disease during treatment with synthetic human calcitonin. Calcium was measured by neutron activation, ulnar density by X-ray photodensitometry, and potassium by counting its natural 40K radioactivity. There was a significant rise in total skeletal mass in a group of 8 patients in the 12 months following the start of therapy, but overall, total bone mass and ulnar density remained constant during treatment. Small mean losses of body potassium were observed (approximately 4%) after several years elapsed on treatment. Over an average period of 12 months after discontinuation of therapy in 21 patients there was no significant mean change in calcium or potassium. The means of the ratios of total body calcium divided by predicted normal calcium (over the whole period of measurement) were 1.08 (males) and 0.99 (females) and were not significantly different. Comparison of the ulnar densities of patients and normal subjects gave similar results. The average ratio of measured to predicted normal potassium was 1.13 (both males and females). Thus there was no indication of depletion in skeletal mass below normal either in the untreated disease or resulting from treatment.

Preparation, characterization, and primate testing of monoclonal antithymocyte globulin

Monoclonal antibodies specific for T cells from both the human and rhesus primate species were detected by their ability to inhibit T cell rosette formation with sheep erythrocytes. The antibodies were shown by fluorescence techniques to react with all thymocytes and peripheral blood T cells but not to B cells, monocytes, platelets, or erythrocytes. Rosette inhibition titers of these antibodies were 30-fold lower when rhesus, rather than human T, cells were used as the rosette-forming cell in assay. Nonetheless, two monoclonal antibodies, of the IgG3 isotype, termed antithymocyte monoclonal (ATM) e.1 and 2.2, were shown to depress selectively circulating T cells to nondetectable levels following single dose administration to rhesus primates and to prolong skin allograft survival in a rhesus primate given a 6-dose course of treatment. The rhesus primates suffered no ill effects and no peripheral blood cellular component other than T cells was depressed. Monoclonal antibody secreting hybridoma cells are capable of producing ATM 3.1 and 3.2 in quantity when grown as peritoneal tumors in selected mouse hybrids. Purification of ATM 3.1 or 3.2 is easily accomplished by affinity chromatography on protein A. These properties suggest that ATM antibodies may become useful immunosuppressive agents in clinical transplantation.