Deinococcus as new chassis for industrial biotechnology: biology, physiology and tools

Deinococcus spp are among the most radiation-resistant micro-organisms that have been discovered. They show remarkable resistance to a range of damage caused by ionizing radiation, desiccation, UV radiation and oxidizing agents. Traditionally, Escherichia coli and Saccharomyces cerevisiae have been the two platforms of choice for engineering micro-organisms for biotechnological applications, because they are well understood and easy to work with. However, in recent years, researchers have begun using Deinococcus spp in biotechnologies and bioremediation due to their specific ability to grow and express novel engineered functions. More recently, the sequencing of several Deinococcus spp and comparative genomic analysis have provided new insight into the potential of this genus. Features such as the accumulation of genes encoding cell cleaning systems that eliminate organic and inorganic cell toxic components are widespread among Deinococcus spp. Other features such as the ability to degrade and metabolize sugars and polymeric sugars make Deinococcus spp. an attractive alternative for use in industrial biotechnology.

Different mutations in the oafA gene lead to loss of O5-antigen expression in Salmonella enterica serovar Typhimurium

AIMS

To analyse genetic changes in the oafA gene explaining the loss of O5-antigen expression in Salmonella Typhimurium and Salm. 4,[5],12:i:-.

METHODS AND RESULTS

The oafA gene in 52 O5-antigen-negative and 77 O5-antigen-positive Salm. Typhimurium (N = 47) and Salm. 4,[5],12:i:- (monophasic Salm. Typhimurium strains, N = 82) was investigated by a combination of PCR screening and DNA sequencing to identify mutations leading to the suppression of the O5-antigen. Various DNA sequence changes within the open reading frame (ORF) of oafA in O5-antigen-negative strains could be identified. In 77% of the O5-antigen-negative strains, a 7-bp deletion of a duplicated sequence within the functional oafA gene led to a frameshift in the ORF. In four strains, an IS4 element and in two, an IS1 element was inserted at different positions. Four other strains carried at different positions single base pair substitutions causing a premature stop codon. Finally, in two strains, a deletion of the oafA 3'end of undetermined size was responsible for the lack of O5-antigen expression. In none of the strains investigated, the complete ORF of oafA was deleted. Primers were designed and used to detect the most prominent variants.

CONCLUSIONS

O5-antigen-negative Salm. Typhimurium and Salm. 4,[5],12:i:- strains carry an oafA pseudogene caused by different genetic events indicating that there is a selection for oafA mutations leading to the loss of O5-antigen expression.

SIGNIFICANCE AND IMPACT OF THE STUDY

The loss of O5-antigen expression may be an example of a common evolutionary mechanism to escape host defence or to adapt to environmental changes. The data are the basis for the development of diagnostic PCR assays for the differentiation of O5-antigen-positive and O5-antigen-negative Salm. Typhimurium and its monophasic (Salm. 4,[5],12:i-) strains.

SCN1A mutation analysis in myoclonic astatic epilepsy and severe idiopathic generalized epilepsy of infancy with generalized tonic-clonic seizures

Severe myoclonic epilepsy in infancy (SMEI), severe idiopathic generalized epilepsy of infancy (SIGEI) with generalized tonic clonic seizures (GTCS), and myoclonic astatic epilepsy (MAE) may show semiological overlaps. In GEFS+ families, all three phenotypes were found associated with mutations in the SCN1A gene. We analyzed the SCN1A gene in 20 patients with non-familial myoclonic astatic epilepsy -- including 12 probands of the original cohort used by Doose et al. in 1970 to delineate MAE. In addition, 18 patients with sporadic SIGEI -- mostly without myoclonic-astatic seizures -- were analyzed. Novel SCN1A mutations were found in 3 individuals. A frame shift resulting in an early premature stop codon in a now 35-year-old woman with a borderline phenotype of MAE and SIGEI (L433fsX449) was identified. A splice site variant (IVS18 + 5 G --> C) and a missense mutation in the conserved pore region (40736 C --> A; R946 S) were detected each in a child with SIGEI. We conclude that, independent of precise syndromic delineation, myoclonic-astatic seizures are not predictive of SCN1A mutations in sporadic myoclonic epilepsies of infancy and early childhood.

Spectrum of cognitive, behavioural and emotional problems in children and young adults with Down syndrome

In comparison to most other groups with intellectual disability individuals with Down syndrome are at lower risk for significant psychopathology, although relative to their typically developing peers they have higher rates of behavioural and emotional problems. A total of 43 Down syndrome patients (21 females and 22 males), who ranged in age from 5.33 to 30.58 years, were examined for the presence of age-related changes in the spectrum of externalizing and internalizing problems. Intelligence tests included Hamburg-Wechsler-Intelligenz Test für Kinder III (HAWIK-III), Hamburg-Wechsler-Intelligenz Test für Erwachsene (HAWIE-R) and Kaufman-Assessment-Battery for Children, German Version (K-ABC). Behavioural and emotional problems were assessed by the the Strengths and Difficulties Questionnaire for Parents, German Version (SDQ) and the Clinical Assessment Scale for Child and Adolescent Psychopathology (CASCAP). IQ was significantly inversly related to the age of patients. Externalizing behaviours (dominant, opposing/refusing, impulsiveness, inattention and increased motor activity) were significantly higher in the 5-10 years old group, whereas internalizing behaviours (shy/insecure, low self confidence, decreased motor activity) where more prevalent in adolescents and adults (10-30 years). Possible relationships between this age-related changes and increased risks of later-onset psychopathology (depression and dementia) are discussed.

Identification of four novel mutations in the C-terminal membrane spanning domain of the ryanodine receptor 1: association with central core disease and alteration of calcium homeostasis

The skeletal muscle ryanodine receptor gene (RYR1; OMIM 180901) on chromosome 19q13.1 encodes the skeletal muscle calcium release channel. To date, more than 25 missense mutations have been identified in RYR1 and are associated with central core disease (CCD; OMIM 117000) and/or the malignant hyperthermia susceptibility phenotype (MHS1; OMIM 145600). The majority of RYR1 mutations are clustered in the N-terminal hydrophilic domain of the protein. Only four mutations have been identified so far in the highly conserved C-terminal region encoding the luminal/transmembrane domain of the protein which forms the ion pore. Three of these mutations have been found to segregate with pure or mixed forms of CCD. We have screened the C-terminal domain of the RYR1 gene for mutations in 50 European patients, diagnosed clinically and/or histologically as having CCD. We have identified five missense mutations (four of them novel) in 13 index patients. The mutations cluster in exons 101 and 102 and replace amino acids which are conserved in all known vertebrate RYR genes. In order to study the functional effect of these mutations, we have immortalized B-lymphocytes from some of the patients and studied their [Ca(2+)](i) homeostasis. We show that lymphoblasts carrying the newly identified RYR1 mutations exhibit: (i) a release of calcium from intracellular stores in the absence of any pharmacological activators of RYR; (ii) significantly smaller thapsigargin-sensitive intracellular calcium stores, compared to lymphoblasts from control individuals; and (iii) a normal sensitivity of the calcium release to the RYR inhibitor dantrolene. Our data suggest the C-terminal domain of RYR1 as a hot spot for mutations leading to the CCD phenotype. If the functional alterations of mutated RYR channels observed in lymphoblastoid cells are also present in skeletal muscles this could explain the predominant symptom of CCD, i.e. chronic muscle weakness. Finally, the study of calcium homeostasis in lymphoblastoid cells naturally expressing RYR1 mutations offers a novel non-invasive approach to gain insights into the pathogenesis of MH and CCD.

A taurine and caffeine-containing drink stimulates cognitive performance and well-being

Caffeine- and taurine-containing drinks have been on the European market for about a decade, and research on the individual constituents of these drinks indicates an improvement in cognitive performance resulting from consumption of such drinks. In this double-blind, placebo-controlled study using 10 graduate students, we obtained the P300 components of event-related potential (ERP) waveforms following an auditory oddball paradigm, measured motor reaction time, and applied the d2 test for the assessment of attention. Status of mood was assessed by the "Basler-Befindlichkeitsbogen" questionnaire, a standard test for evaluation of feelings of well-being. Measurements were made at night, prior to and starting one hour after consumption of energy drink ingredients or placebo. At the end of the experiment (midnight), P300 latency and motor reaction time were significantly longer compared with baseline measurements in the placebo group, but were unchanged in the energy drink group. In the test system for evaluating feelings of well-being, total scores, vitality scores and social extrovertedness scores were significantly decreased in the placebo group but not in the energy drink group. The findings clearly indicate that the mixture of three key ingredients of Red Bull Energy Drink used in the study (caffeine, taurine, glucuronolactone) have positive effects upon human mental performance and mood. These effects may be mediated by the action of caffeine on purinergic (adenosinergic) receptors and taurine modulation of receptors. As half of the study cohort were non-caffeine users, the described effects cannot be explained in terms of the restoration of plasma caffeine levels to normal following caffeine withdrawal.

Effects of transdermal nicotine on cognitive performance in Down's syndrome

Down's syndrome involves age-dependent neuropathological and neurochemical changes similar to Alzheimer's disease, with cholinergic deficits being the most consistent. There is currently no proven treatment for Down's syndrome. We investigated the effect of nicotine-agonistic stimulation with 5 mg transdermal patches, compared with placebo, on cognitive performance in five adults with the disorder. Improvements possibly related to attention and information processing were seen for Down's syndrome patients compared with healthy controls. Our preliminary findings are encouraging, although not generalizable because of small numbers.

Prolonged generalized epileptic seizures triggered by breath-holding spells

We report a 3-year-old female with anoxic-epileptic seizures. Beginning at 11 months of age, she had repeated breath-holding spells with transition into generalized tonic-clonic seizures or status epilepticus. Interictal electroencephalography exhibited no abnormalities. A multidisciplinary diagnostic approach revealed a severely disturbed mother-daughter relationship that was the trigger of the breath-holding spells. Psychotherapy for the mother and daughter led to cessation of the breath-holding spells and, consequently, of the anoxic-epileptic seizures. Her further development was largely normal. We discuss the etiology and treatment of anoxic-epileptic seizures. This case is the first reported case of anoxic epileptic seizures that responded to psychologic rather than antiepileptic treatment. We advocate an initial psychologic assessment to help determine the appropriate treatment in children with recurrent anoxic-epileptic seizures.

Overexpression of DNAse I in brain of patients with Down syndrome

Human DNAse I (EC 3.1.21.1) is an enzyme most probably involved in apoptotic processes. Splicing of the DNAse I primary transcript in normal and apoptotic cells into up to 20 splicing forms and the recent description of a different family of caspase-activated DNAses, hampered studies on the role of DNAse I in apoptosis research. Performing gene hunting in fetal brain of patients with DS we found a sequence with 100% homology to DNAse I and this formed the Rationale for studies in adult DS brain. It was therefore the aim of the study to evaluate DNAse I-mRNA steady state levels in DS brain using adult brain without brain pathologies and Alzheimer's Disease (AD) brain as control, in order to rule out that DNAse I--overexpression may not be specific for DS but rather reflecting apoptosis per se, a hallmark of both disorders. Determination of DNAse I-mRNA steady state levels was carried out by a blotting method in frontal, parietal, temporal occipital lobe and cerebellum. We found significantly increased DNAse I transcripts in brain of DS and AD both, when normalized versus the house-keeping gene beta actin or total RNA. We demonstrate the significant increase of DNAse I--transcript in the pathogenesis of DS and AD suggesting a role for this enzyme in the apoptotic process known to occur in both disorders. We are now going to carry out protein and enzyme activity levels in our laboratory to confirm our findings at the transcriptional level.

Familial idiopathic West syndrome

Two families, each with occurrence of West syndrome in two siblings, are presented. Monozygotic twins in family 1 developed infantile spasms at the age of 4 months. Two female siblings in family 2 started to have seizures at the age of 6 months, but 2 years apart. The family history; development prior to West syndrome; clinical, electroencephalographic, and neuroradiologic findings; diagnostic work-up; and treatment are described. The outcome in family 1 (follow-up after 2 years) showed no conspicuous findings on physical and neurologic examination, and psychomotor development appropriate to cognitive, motor, and language developmental age in both twins. In family 2 (follow-up after 3 and 5 years), the older sister only was one standard deviation below mean in intellectual developmental age. Simultaneous occurrence of infantile spasms in both siblings from these two families but with variable clinical expression suggests there is a genetic susceptibility and variable phenotypic expression. Long-term follow-up will demonstrate whether these cases may be classified as "familial idiopathic West syndrome."

[Calcifying aortic valve stenosis and occult gastrointestinal hemorrhage (Heyde syndrome): description of 2 cases]

The coincidence of aortic valve stenosis and cryptogenic gastrointestinal bleeding usually from angiodysplasia of the cecum and ascending colon has been called Heyde syndrome. The pathophysiologic link between both remains unclear and may be due to subtle changes in plasmatic coagulation. There are some statistic and numerous casuistic reports, and recently the existence of the syndrome has been questioned. We describe two cases of aortic valve stenosis and cryogenic gastrointestinal bleeding in which bleeding subsided after replacement with a bioprosthesis. We give an overview of the current literature.

Recruitment of bone-marrow-derived cells by skeletal and cardiac muscle in adult dystrophic mdx mice

It is commonly accepted, that regenerative capacity of striated muscle is confined to skeletal muscle by activation of satellite cells that normally reside quiescent between the plasmalemma and the basement membrane of muscle fibers. Muscular dystrophies are characterized by repetitive cycles of de- and regeneration of skeletal muscle fibers and by the frequent involvement of the cardiac muscle. Since during the longstanding course of muscular dystrophies there is a permanent demand of myogenic progenitors we hypothesized that this may necessitate a recruitment of additional myogenic precursors from an undifferentiated, permanently renewed cell pool, such as bone marrow (BM) cells. To this end normal and dystrophic (mdx) female mice received bone marrow transplantation (BMT) from normal congenic male donor mice. After 70 days, histological sections of skeletal and cardiac muscle from BMT mice were probed for the donor-derived Y chromosomes. In normal BMT recipients, no Y chromosome-containing myonuclei were detected, either in skeletal or in cardiac muscle. However, in all samples from dystrophic mdx skeletal muscles Y chromosome-specific signals were detected within muscle fiber nuclei, which additionally were found to express the myoregulatory proteins myogenin and myf-5. Moreover, in the hearts of BMT-mdx mice single cardiomyocytes with donor derived nuclei were identified, indicating, that even cardiac muscle cells are able to regenerate by recruitment of circulating BM-derived progenitors. Our findings suggest that further characterization and identification of the BM cells capable of undergoing myogenic differentiation may have an outstanding impact on therapeutic strategies for diseases of skeletal and cardiac muscle.

Use of non-pneumatic antishock garments for ruptured abdominal aortic aneurysm

Two cases of near-fatal aortic abdominal aneurysm (AAA) are described which were successfully stabilized by a new principle for exerting abdominal compression, the non-pneumatic medical antishock trousers (NP-MAST). Obviously, the compression obtained with the NP-MAST suffices for this dramatic emergency. Moreover, compared with pneumatic antishock garments (PASG), the NP-MAST has the advantage of being light, independent of flight height and unable to produce dangerously high pressures. Moreover, it contains no manometers, which could detract the doctor's attention from more important measures. The need for endotracheal intubation in advance to application of any kind of abdominal compression (PASG or NP-MAST) is stressed.

Auditory evoked potentials in young patients with Down syndrome. Event-related potentials (P3) and histaminergic system

Subjects with Down syndrome exhibit various types of cognitive impairment. Besides abnormalities in a number of neurotransmitter systems (e.g. cholinergic), histaminergic deficits have recently been identified. Brainstem auditory evoked potentials (BAEPs) and auditory event-related potentials (ERPs), were recorded from 10 children (aged 11-20 years) with Down syndrome and from 10 age- and sex-matched healthy control subjects. In Down subjects, BAEPs revealed shortened latencies for peaks III and V with shortened interpeak latencies I-III and I-V. ERPs showed a delay of components N1, P2, N2 and P3. In addition, subjects with Down syndrome failed to show P3 amplitude reduction during repeated stimulation. To evaluate the cognitive effects of histaminergic dysfunction, ERPs were recorded from 12 healthy adults (aged 20-28 years) before and after antihistaminergic intervention (pheniramine) compared to placebo. Whereas components N1, P2, N2 remained unchanged after H1-receptor antagonism, P3 latency increased and P3 amplitude showed no habituation in response to repeated stimulation. The results suggest that the characteristic neurofunctional abnormalities present in children with Down syndrome must be the consequence of a combination of structural and neurochemical aberrations. The second finding was that antihistaminergic treatment affects information processing tested by ERPs similar to that seen with anticholinergic treatment.

Brainstem auditory evoked potentials and visually evoked potentials in young patients with IDDM

OBJECTIVE

To investigate whether young IDDM patients develop central nervous dysfunction and to establish a possible relationship with various disease parameters.

RESEARCH DESIGN AND METHODS

Thirty-two patients, aged 13.5 +/- 2 years, with disease duration of 6 +/- 2.6 years and age of onset of 7.7 +/- 3.2 years (group 1), and 21 patients with short-term disease, age 9.7 +/- 3.5 years, duration of disease < 2 years and age of onset of 9.4 +/- 3.3 years (group 2) were compared with age- and sex-matched control subjects. Exclusion criteria were clinical signs of neuropathy, retinopathy, nephropathy, or hearing impairment. Neurophysiological studies included auditory and visually evoked potentials (EPs).

RESULTS

Patients in group 1 revealed increased P100 latencies of visually EPs (103.4 +/- 4.5 vs. 96.8 +/- 3.7 ms) and interpeak latencies I-V of auditory EPs (4.16 +/- 0.10 vs. 3.99 +/- 0.09 ms) and had abnormal latencies (values outside 2.5 SD) in 37%. However, short-term patients (group 2) had results within normal limits compared with control subjects. In group 1, longer disease duration and younger age at onset correlated with an increase of P100 latency (P < 0.001) and IPL I-V (P < 0.001). Patients with a history of severe hypoglycemic episodes had increased latencies compared with patients without hypoglycemia (P < 0.05). Furthermore, metabolic control during the last 2 years was related to P100 latencies (P < 0.05).

CONCLUSIONS

EPs noninvasively detect subclinical central nervous system involvement in children and adolescents with IDDM. Most important risk factors are duration of disease and frequency of severe hypoglycemia.

[Function and structure of families with chronically ill children]

In modern medicine especially the sick child often points out the limits of the psychosocial potentialities. This project investigates the function, structure, coping mechanisms, power and weakness of families with chronically ill children. We investigated 28 children from the nephrological ward and 55 patients from the cardiological department and also their families with the FAM III and compared the obtained T-scores with the results of the control-group (76 families, t-test, analysis of variance). Families with patients after renal transplantation (NTX) pointed out significant worse T-scores than the group with patients on CAPD or with preterminal renal insufficiency and CG (p < 0.05). Within the cardiological groups the differences were not statistically significant, on the other hand the group with patients before heart-operation and the group with patients after palliative heart-operation had better T-scores than the CT (p < 0.05). These results demonstrate that families with children suffering from a chronic renal or heart disease mobilize substantial resources to cope with these problems. By contrast the results of the families with patients after NTX or successful heart surgery are significant worse than the control-group and the other investigated patients groups. Our results come to the conclusion that especially after successful NTX or heart-surgery a psychosocial care of these families is necessary.

Prognosis of childhood epilepsy in newly referred patients

The aim of this study was to investigate the prognosis of childhood epilepsy and to analyze prognostic factors in addition to remission rate in a follow-up of newly referred patients. Two hundred eighty-one patients were followed for a mean period of 5.3 years. Overall, 253 patients (90%) achieved 1-year remission. The beginning of a 1-year seizure-free period was achieved in 77.9% by 1 year, in 84% by 2 years and in 88.6% by 3 years after onset of treatment. Early onset of seizures, symptomatic etiology, and neurologic handicap predicted a worse prognosis. In 44 of 253 children with complete suppression of seizures for 1 year, relapses occurred within the follow-up period. In one child with a relapse, remission could not be achieved in the 2nd year thereafter. In conclusion, our study shows a good prognosis for most children with epilepsy, especially in patients with idiopathic epilepsy and late onset of seizures and without neurologic dysfunction. Moreover, our data strongly suggest that the long-term pattern of seizure control is largely established during the first 2 years of treatment.

Hematologic manifestations and impaired liver synthetic function during valproate monotherapy

In a prospective study 50 children with new onset epilepsy were investigated. Routine screening for complete blood count, serum protein, albumin, gamma-glutamyltransferase (gamma-GT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, and coagulation studies before, 3, 6 and 9 weeks after commencement of antiepileptic therapy with valproate were carried out. Serum B12 and folate levels were also determined in 29 patients. The aim of the study was to evaluate the effect of VPA on these laboratory findings. We found a significant reduction of red blood count and platelet count, whereas MCV showed a significant upward trend. Vitamin B12 levels were elevated after starting VPA therapy. We found no elevations of liver enzymes, but a significant transient reduction of ALT after 3 and 6 weeks and significantly reduced serum protein and albumin after 3, 6 and 9 weeks. Coagulation studies revealed a significant downward trend in serum fibrinogen and upward trend in thrombin time. The other parameters showed no significant changes after onset of VPA treatment. We think that reduced red blood cell and platelet counts, and elevated MCV indicate a direct toxic effect on a hematopoietic precursor or stem cell in patients treated with VPA. Furthermore, reduced protein, albumin and fibrinogen indicate an impaired liver synthetic function in asymptomatic children treated with VPA monotherapy.

Oxyradical damage and mitochondrial enzyme activities in the mdx mouse

A number of studies have already been undertaken to investigate involvement of oxyradicals in muscle diseases by means of measurements of oxyradical protective enzymes. We investigated o-tyrosine, which is a biomarker for OH radical damage in vivo, in 10 mdx and 10 control mice. We also measured mitochondrial enzymes in muscle homogenates of 10 mdx and 10 control mice. Mdx mice had significantly elevated values for o-tyrosine, succinat-phenacinmetosulfat oxidoreductase. NADH O2 oxidoreductase and cytochrome C oxidoreductase. Our findings confirm the suggestion that elevated oxyradical production occurs in muscular dystrophies with lack of dystrophin. Furthermore, our results demonstrate that OH radical damage does not impair mitochondrial enzyme activities in the mdx mouse.

Quantitative EEG in young diabetics

The aim of this study was to investigate the influence of metabolic control on quantitative electroencephalographic (EEG) abnormalities in young diabetic patients. We compared quantitative EEGs of 44 insulin-dependent diabetic patients with age-matched controls. Furthermore, differences in EEG variables of diabetic patients and controls were correlated with the age of onset and duration of diabetes, hemoglobin A1c concentrations, and episodes with severe hypoglycemia. We found a correlation between high values of hemoglobin A1c and decreased relative power of the alpha band. Patients with previous ketoacidotic episodes had increased relative power of the delta/theta band and decreased relative power of the alpha band. Patients with hemoglobin A1c values less than 8.5% exhibited slowing of background activity compared with normal controls. We conclude that metabolic control influences the EEG and that improvement of glucose metabolism is an important factor in avoiding EEG abnormalities in young diabetic patients.

Moderate exercise improves glucose metabolism in uncontrolled elderly patients with non-insulin-dependent diabetes mellitus

Exercise should be an integral part of the treatment in non-insulin-dependent (NIDDM) diabetic patients, yet most of these patients' performance is low, mainly because of their obesity and concomitant macrovascular disease. We studied the influence of a moderate exercise training on parameters of glucose control in NIDDM patients. Forty patients aged 56.6 +/- 6.6 years were assigned randomly according to age and sex into exercise and control groups. The exercise group trained for 45 min 3 times weekly for 12 weeks, while the control group did not change their lifestyle. At the end of the study the exercise group had a significant reduction in plasma levels of triglycerides, fructosamine and glycohemoglobin. The improvement in metabolic control persisted significantly in patients who continued to exercise at varying levels at home during 1 year of follow-up.

Comparison of spinal and epidural anesthesia for patients younger than 50 years of age

To evaluate the respective clinical value of spinal anesthesia with 24-gauge Sprotte needles and epidural anesthesia for younger subjects, 202 patients younger than 50 yr were assigned randomly to undergo one of these two techniques for orthopedic, vascular, urologic, or plastic surgery. Failed blocks occurred in 5% in each group. Spinal anesthesia resulted in significantly less time to achieve sufficient spread of block; a significantly lower incidence of incomplete sensory block at level L5/S1, incomplete motor block, and pain during surgery; and a significantly lower incidence of postlumbar puncture backache (11% vs 30% after epidural anesthesia). The incidence of postdural puncture headache (PDPH) in the spinal and epidural groups was 7% and 4%, respectively (P = not significant), and patient satisfaction was 97% and 93% (P = not significant). Our results demonstrate the effectiveness of both techniques in younger patients, but show that the spinal technique is associated with fewer limitations, suggesting that factors other than PDPH should be considered when choosing between these two techniques.

Kappa/lambda ratio as parameter for evaluation of therapy-resistant epilepsy of childhood

In a prospective study we tested the hypothesis whether an alteration in the immunoglobulin light chain kappa and lambda is an expression of an autoimmune mechanism. We investigated 152 children (84 boys, 68 girls, age 12 months to 16 years). Immunoglobulins were analyzed by kinetic nephelometry. The patients were grouped according to clinical and laboratory parameters. A high kappa/lambda ratio caused by high concentration of the kappa-chain was found in children with therapy-resistant epilepsy. 58% showed a high kappa/lambda ratio, in 28% no distinct association was possible and in 14% false-positive results were obtained. In seizure-free children immunological markers were specific in 71%, whilst 25% could not be characterized and 4% showed false-positive results. This alteration of immunoglobulins therefore can be used as a diagnostic parameter.

Quantitative EEG before and after open heart surgery in children. A significant decrease in the beta and alpha 2 bands postoperatively

Quantitative EEGs of 30 patients undergoing open heart surgery were investigated before, 6 days, 11 days and 44 days after operation. The study was conducted in order to investigate whether quantitative EEGs can show postoperative changes in children after open heart surgery. In 28 children, no new neurological signs of cerebral involvement were seen postoperatively. The most striking feature in these children was a significant decrease in the beta and the alpha 2 bands 6 and 11 days postoperatively. The pattern in the delta band was dominated by an increase 6 days postoperatively. Except for a slight decrease in alpha 2 waves, all variables were restored to preoperative values at 44 days after the operation. We found a significant decrease in plasma sodium and chloride after surgery but children with no or slight declines (1-3 mmol/l) also showed increased slow activity postoperatively. Therefore we conclude that an organic brain syndrome, although usually mild and transient, is a general phenomenon after open heart surgery.

Multipoint mapping of the central core disease locus

A linkage analysis with 12 DNA markers from proximal 19q was performed in eight families with central core disease (CCO). Two-point analysis gave a peak lod score of Z = 4.95 at theta = 0.00 for the anonymous marker D19S190 and of Z = 2.53 at theta = 0.00 for the ryanodine receptor (RYR1) candidate gene. Multipoint linkage data place the CCO locus at 19q13.1, flanked proximally by D19S191/D19S28 and distally by D19S47. This map location includes the RYR1 gene. The results of the linkage study present no evidence for genetic heterogeneity of CCO.

A radiation hybrid map of the distal short arm of human chromosome 11, containing the Beckwith-Wiedemann and associated embryonal tumor disease loci

We describe a high-resolution radiation hybrid (RH) map of the distal short arm of human chromosome 11 containing the Beckwith-Wiedemann gene and the associated embryonal tumor disease loci. Thirteen human 11p15 genes and 17 new anonymous probes were mapped by a statistical analysis of the cosegregation of markers in 102 rodent-human radiation hybrids retaining fragments of human chromosome 11. The 17 anonymous probes were generated from lambda phage containing human 11p15.5 inserts, by using ALU-PCR. A comprehensive map of all 30 loci and a framework map of nine clusters of loci ordered at odds of 1,000:1 were constructed by a multipoint maximum-likelihood approach by using the computer program RHMAP. This RH map localizes one new gene to chromosome 11p15 (WEE1), provides more precise order information for several 11p15 genes (CTSD, H19, HPX, ST5, RNH, and SMPD1), confirms previous map orders for other 11p15 genes (CALCA, PTH, HBBC, TH, HRAS, and DRD4), and maps 17 new anonymous probes within the 11p15.5 region. This RH map should prove useful in better defining the positions of the Beckwith-Wiedemann and associated embryonal tumor disease-gene loci.

Occurrence of Andermann syndrome out of French Canada--agenesis of the corpus callosum with neuronopathy

We report on two siblings, a boy and a girl, with agenesis of corpus callosum and neuronopathy. The children show diffuse hypotonia, delayed motor and mental development. Neurophysiological examinations revealed reduction of the motor nerve conduction velocity, absence of sensory nerve action potentials, abnormal somatosensory and visual evoked potentials. Nerve biopsies showed reduced density of myelinated and unmyelinated fibres in both children. We also found signs of hypomyelination and suggest this is secondary to degeneration of peripheral sensory and motor neurons. Our findings are consistent with the diagnosis of Andermann syndrome. This is the first report of the occurrence of Andermann syndrome out of French Canada.

Increased hypothalamic [3H]flunitrazepam binding in hypothalamic-pituitary-adrenal axis hyporesponsive Lewis rats

We have previously demonstrated that susceptibility of Lewis (LEW/N) rats to inflammatory disease, compared to relatively resistant Fischer (F344/N) rats, is related to deficient glucocorticoid counter-regulation of the immune response resulting from deficient corticotropin-releasing hormone (CRH) responsiveness to inflammatory and other stress mediators. The GABA/benzodiazepine receptor complex is an important negative modulator of CRH secretion and responsiveness to excitatory stimuli. In this study, we have examined in vitro binding of [3H]flunitrazepam to hypothalamic membrane preparations from LEW/N and F344/N rats. LEW/N rats had significantly more hypothalamic benzodiazepine binding sites (Bmax) than F344/N rats, but there were no differences in benzodiazepine binding affinities (Kd) between these two strains. The differences in benzodiazepine receptor number were consistent with the respective plasma corticosterone levels in the two strains, and with previous work indicating a negative correlation between corticosterone levels and benzodiazepine binding site number. Adrenalectomy of F344/N rats increased benzodiazepine binding to levels comparable to LEW/N animals and treatment of adrenalectomized F344/N rats with DEX resulted in lowering of benzodiazepine Bmax to levels that did not differ significantly from those of intact F344/N rats. There was no significant change in receptor number in either adrenalectomized or DEX-treated LEW/N rats. These findings suggest that basal benzodiazepine receptor differences between these strains may be partially related to strain differences in corticosterone levels, however that additional factors may contribute to maintenance of these differences in LEW/N rats. Since benzodiazepines attenuate hypothalamic CRH secretion through GABAergic inhibition, we suggest that strain differences in receptor number could also augment strain differences in hypothalamic-pituitary-adrenal axis function through differential sensitivity to GABA-mediated feedback.

[Computerized tomography in epilepsy in children]

We present a retrospective study of 160 children attending our epilepsy out-patient department. Computed tomography (CT) was performed on 123 (77%) patients, namely all children with the exception of those with febrile seizures, typical absence seizures, and benign Rolandic epilepsy. Incidence of CT abnormalities and their correlation with clinical features were evaluated. The CT scan was normal in 84 and abnormal in 39 patients. Although in general, the detection of abnormality on CT will not alter the management of the child, in a small percentage (2%) of our cases a lesion treatable by surgery was discovered. The indications for CT are summarized.

[Circulatory distribution of intravenously injected metallic mercury]

The mode of distribution and sites of deposition of mercury are discussed on the basis of the example of a 21-year old female nurse who had injected 4.5 ml of metallic mercury into her left cubital vein with suicidal intent, the findings being compared with the reports by 11 other authors. In particular, the influence of gravity on the distribution in the organism is emphasised. The proof of the decrease of an intrapulmonarily deposited amount of mercury within the observation period of 14 months furnishes ample evidence of the importance of a chronic absorptive mercury intoxication.

[On the occurrence of fatty acids in animal fats. 1st communication (author's transl)]

The fats of a number of organs, and of sausages made from these organs, were examined regarding their composition of fatty acids. The main emphasis was placed on determining the contents of polyunsaturated fatty acids. The values were expressed as "arachidonic acid equivalents", on the effects of lowering the level of lipids in the blood. In the tested organs the fat contained 9-19% arachidonic acid equivalent. In the sausages that fat contained 5.9-8.9% arachidonic acid equivalent (i.e. 2.1-2.5 g arachidonic acid equivalent per 100 g of sausage). High contents of arachidonic acid were found particularly in fat from livers.