Oral sialic acid supplementation in NANS-CDG: Results of a single center, open-label, observational pilot study

NANS-CDG is a congenital disorder of glycosylation (CDG) caused by biallelic variants in NANS, encoding an essential enzyme in de novo sialic acid synthesis. It presents with intellectual developmental disorder (IDD), skeletal dysplasia, neurologic impairment, and gastrointestinal dysfunction. Some patients suffer progressive intellectual neurologic deterioration (PIND), emphasizing the need for a therapy. In a previous study, sialic acid supplementation in knockout nansa zebrafish partially rescued skeletal abnormalities. Here, we performed the first in-human pre- and postnatal sialic-acid study in NANS-CDG. In this open-label observational study, 5 patients with NANS-CDG (range 0-28 years) were treated with oral sialic acid for 15 months. The primary outcome was safety. Secondary outcomes were psychomotor/cognitive testing, height and weight, seizure control, bone health, gastrointestinal symptoms, and biochemical and hematological parameters. Sialic acid was well tolerated. In postnatally treated patients, there was no significant improvement. For the prenatally treated patient, psychomotor and neurologic development was better than two other genotypically identical patients (one treated postnatally, one untreated). The effect of sialic acid treatment may depend on the timing, with prenatal treatment potentially benefiting neurodevelopmental outcomes. Evidence is limited, however, and longer-term follow-up in a larger number of prenatally treated patients is required.

A Cross-Sectional Study of the Dermatological Manifestations of Patients with Fabry Disease and the Assessment of Angiokeratomas with Multimodal Imaging

Fabry disease (FD) is a multisystemic X-linked lysosomal storage disease that presents with angiokeratomas (AKs). Our objective was to investigate the clinical and morphologic features of AKs and to present two experimental techniques, multispectral imaging (MSI) and non-linear microscopy (NLM). A thorough dermatological examination was carried out in our 26 FD patients and dermoscopic images (n = 136) were evaluated for specific structures. MSI was used for the evaluation of AKs in seven patients. NLM was carried out to obtain histology samples of two AKs and two hemangiomas. Although AKs were the most common manifestation, the majority of patients presented an atypical distribution and appearance, which could cause a diagnostic challenge. Dermoscopy revealed lacunae (65%) and dotted vessels (56%) as the most common structures, with a whitish veil present in only 25%. Autofluorescence (405 nm) and diffuse reflectance (526 nm) images showed the underlying vasculature more prominently compared to dermoscopy. Using NLM, AKs and hemangiomas could be distinguished based on morphologic features. The clinical heterogeneity of FD can result in a diagnostic delay. Although AKs are often the first sign of FD, their presentation is diverse. A thorough dermatological examination and the evaluation of other cutaneous signs are essential for the early diagnosis of FD.

Clinical evaluation of rare copy number variations identified by chromosomal microarray in a Hungarian neurodevelopmental disorder patient cohort

BACKGROUND

Neurodevelopmental disorders are genetically heterogeneous pediatric conditions. The first tier diagnostic method for uncovering copy number variations (CNVs), one of the most common genetic etiologies in affected individuals, is chromosomal microarray (CMA). However, this methodology is not yet a routine molecular cytogenetic test in many parts of the world, including Hungary. Here we report clinical and genetic data of the first, relatively large Hungarian cohort of patients whose genetic testing included CMA.

METHODS

Clinical data were retrospectively collected for 78 children who were analyzed using various CMA platforms. Phenotypes of patients with disease-causing variants were compared to patients with negative results using the chi squared/Fisher exact tests.

RESULTS

A total of 30 pathogenic CNVs were identified in 29 patients (37.2%). Postnatal growth delay (p = 0.05564), pectus excavatum (p = 0.07484), brain imaging abnormalities (p = 0.07848), global developmental delay (p = 0.08070) and macrocephaly (p = 0.08919) were more likely to be associated with disease-causing CNVs.

CONCLUSION

Our results allow phenotypic expansion of 14q11.2 microdeletions encompassing SUPT16H and CHD8 genes. Variants of unknown significance (n = 24) were found in 17 patients. We provide detailed phenotypic and genetic data of these individuals to facilitate future classification efforts, and spotlight two patients with potentially pathogenic alterations. Our results contribute to unraveling the diagnostic value of rare CNVs.

Microdeletions in 1q21 and 8q12.1 depict two additional molecular subgroups of Silver-Russell syndrome like phenotypes

Background

Silver-Russell syndrome (SRS) is a genetic disorder characterized by intrauterine and postnatal growth restriction, relative macrocephaly at birth, body asymmetry and typical facial features. Clinical and molecular heterogeneity is described in SRS. Common causes are loss of methylation of the imprinting center 1 in 11p15 and maternal uniparental disomy of chromosome 7. Other genetic alterations include disturbances of imprinted regions in 14q32, 7q32 and 11p15 as well as submicroscopic deletions and duplications. Single nucleotide variants in genes like IGF2, HMGA2, PLAG1, CDKN1C have also been identified in patients with SRS phenotypes. However, routine molecular diagnostics usually focus on 11p15 and chromosome 7, while less frequent causes are not systematically addressed.

Results

Here we report two patients with SRS features in which molecular karyotyping revealed microdeletions in 1q21 and 8q12.1 respectively. In a 3.5-year-old girl with postnatal growth restriction, feeding difficulties, relative macrocephaly and distinct SRS features a 2 Mb deletion in 1q21.1q21.2 was identified. Our second case is a 1.5-year-old boy with intrauterine and postnatal growth restriction, feeding difficulties and distinct facial features with a 77 kb deletion in 8q12.1 affecting PLAG1 as the only protein-encoding gene with known function.

Conclusions

The 1q21 region has not yet been assigned as an SRS region, although six patients with the same deletion and SRS features including relative macrocephaly have been described before. This new case adds to the evidence that distal 1q21 should be annotated as an SRS candidate region. The PLAGL1 alteration is the smallest deletion in 8q12.1 ever reported in a patient with SRS phenotype and it finally confirms that PLAG1 is the SRS causing gene in 8q12.1. To increase the diagnostic yield in patients with suspected SRS, we recommend both molecular karyotyping and next generation sequencing-based approaches.

A 22q11.2-microdeletiós szindróma klinikai jellemzői

Összefoglaló. Bevezetés: A sokszínű tünetspektrummal jellemezhető DiGeorge-szindróma leggyakoribb oka a 22q11.2-microdeletio; incidenciája 1/4000–6000. Célkitűzés: A DiGeorge-szindrómára gyanús hazai betegcsoport 22q11.2-microdeletióval társult tüneteinek/panaszainak részletes feltérképezése, a betegség incidenciájának becslése és egy magyarországi 22q11.2-microdeletiós szindróma regiszter létrehozása. Módszer: 2005 és 2019 között a Semmelweis Egyetem II. Gyermekgyógyászati Klinikájára DiGeorge-szindróma gyanújával beutalt és a Veleszületett Rendellenességek Országos Nyilvántartása által regisztrált DiGeorge-szindrómás betegek adatait dolgoztuk fel. A fenotípusjegyeket a Humán Fenotípus Ontológia kódrendszer alapján határoztuk meg. Eredmények: A vizsgálatba 114, igazolt DiGeorge-szindrómás és 113, FISH-vizsgálattal microdeletiót nem hordozó, de klinikailag a DiGeorge-szindróma tüneteit mutató beteget vontunk be. A diagnózis felállításakor a betegek átlagéletkora 5,88 (± 9,66 SD) év volt, eddig a betegek 54,9%-a legalább egy szívműtéten átesett. A betegek leggyakoribb tünetei a kamrai sövényhiány, a mélyen ülő fülek, a gótikus szájpad, a motoros fejlődési elmaradás és a visszatérő fertőzések voltak. Megbeszélés: A DiGeorge-szindróma becsült incidenciája hazánkban 1/12 500, közöttük magas a többszörösen veszélyeztetett újszülöttek és a műtéti korrekcióra szorulók aránya. A diagnózis hazánkban 2–3 évvel korábban történik a nemzetközi átlaghoz viszonyítva. Következtetés: A létrehozott regiszterünk alapján Magyarországon a kórkép aluldiagnosztizált. Minden conotruncalis szívfejlődési rendellenesség vagy jelentős kamrai sövényhiány esetén citogenetikai vizsgálat javasolt a DiGeorge-szindróma felmerülő gyanúja miatt. Negatív lelet esetén az atípusos töréspontú microdeletiók azonosítására komparatív genomiális hibridizáció vagy multiplex ligatiofüggő próbaamplifikációs vizsgálat javasolt. A betegek számára multidiszciplináris ellátás szükséges, III-as progresszivitási szintű újszülött intenzív részlegen, gyermekkardiológus és klinikai genetikus részvételével. Orv Hetil. 2022; 163(1): 21–30.

Summary. Introduction: The 22q11.2 microdeletion syndrome is the most common cause of DiGeorge syndrome, showing a wide phenotypic spectrum and has an estimated incidence of 1/4000–6000 livebirths. Objective: Detailed characterization of the clinical signs/symptoms associated with 22q11.2 deletion, estimation of the national incidence via establishing a Hungarian register. Method: Retrospective data between 2005 and 2019 from the 2nd Department of Paediatrics, Semmelweis University and from national database of congenital anomalies were obtained. Phenotypic abnormalities were described using the Human Phenotype Ontology nomenclature. Results: A cohort of 114 DiGeorge patients and 113 patients negative for FISH testing were included. The mean age of patients at diagnosis was 5.88 (± 9.66 SD) years and 54.9% of patients had at least one heart surgery until diagnosis. The main identified symptoms were ventricular septal defect, low-set ears, recurrent infections, high narrow palate and motor development delay. Discussion: The estimated incidence of DiGeorge syndrome in Hungary is 1/12 500 births, the frequency of infants at high risk and in need for surgery is high. Diagnosis is established 2–3 years earlier as compared to the international average. Conclusion: Based on the established Hungarian register, the incidence is lower compared to international data. In the case of conotruncal heart anomaly and ventricular septal defects, cytogenetic testing is recommended for the increased probability of DiGeorge syndrome. For second-tier testing, comparative genome hybridization or multiplex ligation-dependent probe amplification are recommended to identify atypical microdeletions. Newborns with DiGeorge syndrome require special care in perinatal intensive centers including pediatric cardiology and genetic counseling. Orv Hetil. 2022; 163(1): 21–30.

Deletion of 16q22.2q23.3 in a Boy with a Phenotype Reminiscent of Silver-Russell Syndrome

A 15-month-old boy presented with growth and global developmental delay, feeding difficulties, sleep disturbance and several minor anomalies, including a large anterior fontanel, relative macrocephaly, and a triangular face. Clinical suspicion prompted genetic investigations for Silver-Russell syndrome and related disorders. SNP array analysis led to the diagnosis of an approximately 10-Mb large deletion of the long arm in chromosome 16q22.2q23.3. Interstitial deletions of 16q show a wide variability of related features; however, considering the differences in size and location of the deletions in the known patients, the phenotypic overlap is surprising. Here, we report a novel microdeletion, compare the proband with data from scientific literature and international databases, and discuss possible diagnostic implications.

Diagnostic difficulties and possibilities of NF1-like syndromes in childhood

BACKGROUND

Neurofibromatosis type 1 (NF1), which is caused by heterozygous inactivating pathogenic variants in the NF1, has poor phenotypic expressivity in the early years of life and there are numerous conditions, including many other tumor predisposition syndromes, that can mimic its appearance. These are collectively termed NF1-like syndromes and are also connected by their genetic background. Therefore, the NF1's clinical diagnostic efficiency in childhood could be difficult and commonly should be completed with genetic testing.

METHODS

To estimate the number of syndromes/conditions that could mimic NF1, we compiled them through an extensive search of the scientific literature. To test the utility of NF1's National Institutes of Health (NIH) clinical diagnostic criteria, which have been in use for a long time, we analyzed the data of a 40-member pediatric cohort with symptoms of the NF1-like syndromes' overlapping phenotype and performed NF1 genetic test, and established the average age when diagnostic suspicion arises. To facilitate timely identification, we compiled strongly suggestive phenotypic features and anamnestic data.

RESULTS

In our cohort the utility of NF1's clinical diagnostic criteria were very limited (sensitivity: 80%, specificity: 30%). Only 53% of children with clinically diagnosed NF1 had a detectable NF1 pathogenic variation, whereas 40% of patients without fulfilled clinical criteria tested positive. The average age at first genetic counseling was 9 years, and 40% of children were referred after at least one tumor had already been diagnosed. These results highlight the need to improve NF1-like syndromes' diagnostic efficiency in childhood. We collected the most extensive spectrum of NF1-like syndromes to help the physicians in differential diagnosis. We recommend the detailed, non-invasive clinical evaluation of patients before referring them to a clinical geneticist.

CONCLUSIONS

Early diagnosis of NF1-like syndromes can help to prevent severe complications by appropriate monitoring and management. We propose a potential screening, diagnostic and management strategy based on our findings and recent scientific knowledge.

NANS-CDG: Delineation of the Genetic, Biochemical, and Clinical Spectrum

Background: NANS-CDG is a recently described congenital disorder of glycosylation caused by biallelic genetic variants in NANS, encoding an essential enzyme in de novo sialic acid synthesis. Sialic acid at the end of glycoconjugates plays a key role in biological processes such as brain and skeletal development. Here, we present an observational cohort study to delineate the genetic, biochemical, and clinical phenotype and assess possible correlations.

Methods: Medical and laboratory records were reviewed with retrospective extraction and analysis of genetic, biochemical, and clinical data (2016–2020).

Results: Nine NANS-CDG patients (nine families, six countries) referred to the Radboudumc CDG Center of Expertise were included. Phenotyping confirmed the hallmark features including intellectual developmental disorder (IDD) (n = 9/9; 100%), facial dysmorphisms (n = 9/9; 100%), neurologic impairment (n = 9/9; 100%), short stature (n = 8/9; 89%), skeletal dysplasia (n = 8/9; 89%), and short limbs (n = 8/9; 89%). Newly identified features include ophthalmological abnormalities (n = 6/9; 67%), an abnormal septum pellucidum (n = 6/9; 67%), (progressive) cerebral atrophy and ventricular dilatation (n = 5/9; 56%), gastrointestinal dysfunction (n = 5/9; 56%), thrombocytopenia (n = 5/9; 56%), and hypo–low-density lipoprotein cholesterol (n = 4/9; 44%). Biochemically, elevated urinary excretion of N-acetylmannosamine (ManNAc) is pathognomonic, the concentrations of which show a significant correlation with clinical severity. Genotypically, eight novel NANS variants were identified. Three severely affected patients harbored identical compound heterozygous pathogenic variants, one of whom was initiated on experimental prenatal and postnatal treatment with oral sialic acid. This patient showed markedly better psychomotor development than the other two genotypically identical males.

Conclusions: ManNAc screening should be considered in all patients with IDD, short stature with short limbs, facial dysmorphisms, neurologic impairment, and an abnormal septum pellucidum +/– congenital and neurodegenerative lesions on brain imaging, to establish a precise diagnosis and contribute to prognostication. Personalized management includes accurate genetic counseling and access to proper supports and tailored care for gastrointestinal symptoms, thrombocytopenia, and epilepsy, as well as rehabilitation services for cognitive and physical impairments. Motivated by the short-term positive effects of experimental treatment with oral sialic, we have initiated this intervention with protocolized follow-up of neurologic, systemic, and growth outcomes in four patients. Research is ongoing to unravel pathophysiology and identify novel therapeutic targets.

Chromosome 2q14.3 microdeletion encompassing CNTNAP5 gene in a patient carrying a complex chromosomal rearrangement

We report a patient with loss of chromosome region 2q14.3 encompassing exon 1 of the gene CNTNAP5. The deletion occurred in association with a de novo complex chromosomal rearrangement, characterized by routine G-banding, fluorescence in situ hybridization and microarray analysis. The presented patient's phenotype is dominated by severe early childhood weight gain, severe speech delay and behavioural problems. To our knowledge, a few similar patients have been reported previously. CNTNAP5 is a member of the neurexin gene family and is associated with autism spectrum disorder and potentially other behavioural and neurodevelopmental disorders. Recent data point to its possible role in obesity and/or metabolism. The phenotype of the herein presented pediatric patient corroborates CNTNAP5's pathogenic role in human disease.

Clinical and genetic findings in Hungarian pediatric patients carrying chromosome 16p copy number variants and a review of the literature

The short arm of chromosome 16 (16p) is enriched for segmental duplications, making it susceptible to recurrent, reciprocal rearrangements implicated in the etiology of several phenotypes, including intellectual disability, speech disorders, developmental coordination disorder, autism spectrum disorders, attention deficit hyperactivity disorders, obesity and congenital skeletal disorders. In our clinical study 73 patients were analyzed by chromosomal microarray, and results were confirmed by fluorescence in situ hybridization or polymerase chain reaction. All patients underwent detailed clinical evaluation, with special emphasis on behavioral symptoms. 16p rearrangements were identified in 10 individuals. We found six pathogenic deletions and duplications of the recurrent regions within 16p11.2: one patient had a deletion of the distal 16p11.2 region associated with obesity, while four individuals had duplications, and one patient a deletion of the proximal 16p11.2 region. The other four patients carried 16p variations as second-site genomic alterations, acting as possible modifying genetic factors. We present the phenotypic and genotypic results of our patients and discuss our findings in relation to the available literature.

Similar Cause, Different Phenotype: SOX9 Enhancer Duplication in a Family

INTRODUCTION

46,XX ovotesticular disorder of sex development (DSD), as defined by the Chicago consensus in 2006, is characterized by histologically confirmed testicular and ovarian tissue in an individual with a 46,XX karyotype and a wide phenotypic spectrum from female to male appearance.

CASE PRESENTATION

We report the case of two 46,XX sex determining region Y (SRY) gene-negative siblings and their 46,XY father with an approximately 150 kilobase pair (kbp) duplication upstream of SOX9 (SRY-box 9) gene's transcriptional start site on chromosome 17 (chr17), which involved SOX9's minimal critical 46,XX sex reversal region. This duplication is sufficient to trigger male development in the absence of Y-chromosomal material and can lead to various degrees of masculinization in 46,XX individuals by overexpression of SOX9. Based on anamnestic information and pedigree analysis, another possible carrier of this copy number variation (CNV) could have been the father's sister.

DISCUSSION

By comparing the duplications of our two sibling patients and previously reported similar cases, we suggest that the small differences between their breakpoints could alternatively modify the inner structure and functioning of SOX9'stopologically associated domain (TAD) due to the differing fine TAD arrangements. Our data support the phenotypic modularity impact - incomplete penetrance and variable expressivity - of very similar but non-identical CNVs, which are possibly inherited across three generations.

Frequency of KCNQ1 variants causing loss of methylation of Imprinting Centre 2 in Beckwith-Wiedemann syndrome

Background

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder caused by disturbances of the chromosomal region 11p15.5. The most frequent molecular finding in BWS is loss of methylation (LOM) of the Imprinting Centre 2 (IC2) region on the maternal allele, which is localised in intron 10 of the KCNQ1 gene. In rare cases, LOM of IC2 has been reported in families with KCNQ1 germline variants which additionally cause long-QT syndrome (LQTS). Thus, a functional link between disrupted KCNQ1 transcripts and altered IC2 methylation has been suggested, resulting in the co-occurrence of LQTS and BWS in case of maternal inheritance. Whereas these cases were identified by chance or in patients with abnormal electrocardiograms, a systematic screen for KCNQ1 variants in IC2 LOM carriers has not yet been performed.

Results

We analysed 52 BWS patients with IC2 LOM to determine the frequency of germline variants in KCNQ1 by MLPA and an amplicon-based next generation sequencing approach. We identified one patient with a splice site variant causing premature transcription termination of KCNQ1.

Conclusions

Our study strengthens the hypothesis that proper KCNQ1 transcription is required for the establishment of IC2 methylation, but that KCNQ1 variants cause IC2 LOM only in a small number of BWS patients.

What should we consider in the case of combined Down- and 47,XY,+i(X)(q10) Klinefelter syndromes? The unique case of a male newborn and review of the literature

Background

Double aneuploidies - especially in combination with structural aberrations - are extremely rare among liveborns. The most frequent association is that of Down (DS) and Klinefelter syndromes (KS). We present the case of a male newborn with a unique 47,XY,+ 21[80%]/48,XY,+i(X)(q10),+ 21[20%] karyotype, hypothesize about his future phenotype, discuss the aspects of management and review the literature.

Case presentation

The additional association of isochromosome Xq (i(X)(q10)) could be the result of a threefold non-disjunction event. 47,XY,+i(X)(q10) KS is not common and its symptoms differ from the classical KS phenotype. In combined DS and i(X)(q10) KS, the anticipatory phenotype is not simply the sum of the individual syndromic characteristics. This genotype is associated with higher risk for several diseases and certain conditions with more pronounced appearance: emotional and behavioral disorders; poorer mental and physical quality of life; lower muscle mass/tone/strength; connective tissue weakness; muscle hypotonia and feeding difficulties; osteopenia/−porosis with earlier beginning and faster progression; different types of congenital heart diseases; more common occurrence of hypertension; increased susceptibility to infections and female predominant autoimmune diseases; higher risk for hematological malignancies and testicular tumors.

Conclusions

In multiple aneuploidies, the alterations have the potential to weaken or enhance each other, or they may not have modifying effects at all. Prenatal ultrasound signs are not obligatory symptoms of numerous chromosomal anomalies (specifically those involving supernumerary sex chromosomes), therefore combined prenatal screening has pertinence in uncomplicated pregnancies as well.

[Trisomy 9p and clinical heterogeneity: case report of an unusual presentation]

Whole or partial trisomy of the short arm of chromosome 9 (9p) is considered to be one of the more frequent chromosome abnormalities compatible with life. The duplication may affect various organs, however the most common symptoms are certain specific facial dysmorphisms and abnormalities of the fingers, toes and nails. A one month old boy presented with failure to thrive, jaundice, ventricular septal defect (VSD) and dysmorphic face. He displayed symptoms of heart failure. The cardiologic examination revealed a significant VSD, hypoplasia of the aortic arch, pulmonary hypertension, decompensated circulatory failure and moderate left ventricle dysfunction. Routine cytogenetic analysis revealed a supernumerary marker chromosome. Fluorescence in situ hybridization (FISH) identified this as the short arm of chromosome 9. The child's karyotype was determined as 47,XY,+der(9)dup(9)(p10p24)dn. Due to his worsening condition and the high risk of the operation, it was decided to forego the procedure. After a short palliative care the child passed away. The child's clinical presentation and the uncharacteristic severity of his condition show that chromosome abnormalities involving duplicated genetic material are extremely heterogeneous. Thus treatment of each child should be individualized and may also involve difficult ethical considerations. Orv Hetil. 2018; 159(47): 1994-2000.

[Examination of sex chromosome abnormalities in childhood]

INTRODUCTION

Early diagnosis of sex chromosome abnormalities is important because of prevention, family planning and optimal therapy.

AIM

Investigation of the relationship between phenotype, age at time of diagnosis and therapeutic options in sex chromosome aberrations.

METHOD

Processing data of 51 children with sex chromosome abnormalities who were diagnosed between 2009 and 2014 and examined at the 2nd. Department of Pediatrics, Semmelweis University, by the methods of anamnesis, family tree analysis, physical examination, karyotype analysis and fluorescent in situ hybridisation.

RESULTS

41% of the patients were diagnosed with Turner-, 18% with Klinefelter-, 10% with double-Y-, 6% with triple- and poly-X-syndrome, 19% with other gonadal dysgenesis and 6% with other abnormality. The average age at diagnosis: Turner- and Klinefelter-syndrome 10 years, other gonadal dysgenesis 9 years, 46,XX,t(X;10) 17 years, other abnormalities 1-2 years.

CONCLUSIONS

Numerical aberrations of the sex chromosomes are more common than structural aberrations. Klinefelter-, triple- and poly-X-syndromes are underdiagnosed in childhood. Early diagnosis of Turner-syndrome and other gonadal dysgenesis is necessary to optimise therapy and prevent associated diseases. This can be achieved by modern prenatal diagnostic methods and targeted activity of family pediatricians. Orv Hetil. 2018; 159(27): 1121-1128.

Age-related changes in acute central leptin effects on energy balance are promoted by obesity

Leptin is a key catabolic regulator of food intake (FI) and energy expenditure. Both aging and obesity have been shown to induce leptin-resistance. The present study aimed to analyze age-related changes in the anorexigenic and hypermetabolic responsiveness to acute intracerebroventricular leptin administration in different age-groups of normally fed male Wistar rats (adult and old rats from 3 to 24months of age, NF3 to NF24, respectively). The expressions of the long form of the leptin receptor (Ob-Rb) and inhibitory SOCS3 genes were also assessed by quantitative RT-PCR in the arcuate nucleus (ARC). The influence of high-fat diet-induced obesity (HF) on the anorexigenic leptin effects were also tested in younger and older middle-aged groups (HF6 and HF12). Leptin-induced anorexia varied with age: leptin suppressed re-feeding FI (following 48-h fasting) strongly in young adult (NF3), but not in younger or older middle-aged (NF6 or NF12) or in aging (NF18) rats. However, anorexigenic leptin effects reached statistical significance again in old NF24 rats. Leptin-induced hypermetabolism, on the other hand, showed monotonous age-related decline and disappeared by old age. Ob-Rb expression declined until 12months of age followed by a partial recovery in NF18 and NF24 groups. On the other hand, SOCS3 expression was high in NF6 and NF18 and to some extent in NF24 rats. Age-related alterations of Ob-Rb and SOCS3 expression in the ARC may partly contribute to the explanation of age-related variations in anorexigenic but not hypermetabolic leptin effects. High-fat diet-induced obesity was associated with resistance to leptin-induced anorexia in HF6, similar to that seen in NF6. However, instead of the expected leptin-resistance in HF12, a strong leptin-induced suppression of re-feeding was detected in these obese middle-aged rats. Our results suggest that acute central effects of leptin on anorexia and hypermetabolism change in disparate ways during aging, implying separate mechanisms (e.g. signal transduction pathways) of different leptin actions. The age-related pattern shown by leptin-induced anorexia may contribute to the explanation of middle-aged obesity, and partly to that of aging anorexia. Our findings concerning obese rats are in accord with previous observations on anorexigenic effects of peripherally administered cholecystokinin: diet-induced obesity appeared to accelerate the development of age-related regulatory alterations. Similarly, our present data also raise the possibility that chronic diet-induced obesity promotes responsiveness to centrally applied leptin at least concerning anorexigenic effects.

[Frequency of oral candidiasis in stem cell transplant patients]

This study included 80 persons with haematological malignancies receiving stem cell transplantation (SCT) who were followed up for a period of 24 months. Authors focused on the patients' oral health state and on the correlation between the fungal colonisation of the oral cavity and the unstimulated whole saliva flow rate, before and after the stem cell transplantation. Carious teeth could be detected in 20 out of the 80 persons, although all of them were examined and treated by their dentists before taking part in the SCT program. Fungal colonization could be shown in 16 patients before the conditioning phase and in 19 subjects during the aplasia phase of SCT. Hyposalivation (unstimulated whole saliva flow rate < or = 0.1 mI/min) was detected in 28 patients. In conclusion there was a higher incidence of Candida albicans and other fungal colonization in SCT patients suffering from hyposalivation than in those of normal saliva flow rate.

Incidence of oropharyngeal candidosis in stem cell transplant (SCT) patients

Eighty persons with haematological malignancies receiving stem cell transplantation (SCT) were examined over a 24 months period. Hyposalivation, a common complaint in patients treated by intensive chemotherapy and radiotherapy can predispose to oral candidal colonisation as well. This study was focused on correlation between the fungal colonisation of the oral cavity and the total unstimulated saliva flow rate of 80 patients with haematological malignancies before and after stem cell transplantation and in addition, on their oral health state. Despite the fact that prior to being involved in the transplantation programme, the patients were subjected to dental examination and decayed teeth were found in 20 out of 80 patients (25%). From the 2233 different oropharyngeal specimens fungi were isolated before conditioning from 16 patients (20%), and during aplasia from 19 patients (23.7%). Objective xerostomia (unstimulated total saliva flow rate < or = 0.1 ml/min) was detected in 28 patients (35%). Stem cell transplant patients with pretransplant mouth dryness had higher incidence of Candida albicans and other fungal colonisation than those with normal saliva secretion.

Cross-reactivity between human adenoviruses in delayed-type hypersensitivity

The aim of this study was to determine the antigen responsible for the induction of delayed-type hypersensitivity (DTH) by human adenoviruses (Ads). The estimation of DTH was based on measurement of the extent of swelling of the hind footpads of mice. CsCl density gradient-purified human Ad serotype 6 (Ad6) induced DTH in a dose-dependent manner. In Ad6-sensitized mice, DTH could be elicited by serotypes belonging to the same species of human Ads (types 1 and 5) and by a serotype (type 3) belonging to another species. Latex particles coated with purified hexon antigen prepared from Ad5 had the capacity to sensitize mice and elicit a DTH reaction. We suggest that, for serotypes belonging to species C, the cross-reactive highly conserved T cell epitope of the hexon protein might be responsible for the DTH induction, and furthermore the same epitope might result in the cross-reactivity between serotypes 3 and 6. The possible importance of these data is discussed in relation to human gene therapy through the application of Ad vectors.

Prediction of ozone concentration in ambient air using multivariate methods

Multivariate statistical methods including pattern recognition (Principal Component Analysis--PCA) and modeling (Multiple Linear Regression--MLR, Partial Least Squares--PLS, as well as Principal Component Regression--PCR) methods were carried out to evaluate the state of ambient air in Miskolc (second largest city in Hungary). Samples were taken from near the ground at a place with an extremely heavy traffic. Although PCA is not able to determine the significance of variables, it can uncover their similarities and classify the cases. PCA revealed that it is worth to separate day and night data because different factors influence the ozone concentrations during all day. Ozone concentration was modeled by MLR and PCR with the same efficiency if the conditions of meteorological parameters were not changed (i.e. morning and afternoon). Without night data, PCR and PLS suggest that the main process is not a photochemical but a chemical one.

Retrospective detection of a subclinical hepatitis A virus (HAV) epidemic affecting juvenile cohorts of the Hungarian population

Sero-epidemiological surveys of serum samples taken in 1982, 1987, 1994 and 1999 have been performed with hepatitis A virus-specific (HAV-specific) serological tests. Results obtained during these surveys show that the proportion of seropositive blood donors decreased from 69% to 18% within 17 years. The authors have recognised a (mainly subclinical) epidemic, affecting about 115000 teenagers in 1992-1994 in Hungary, is a threatening phenomenon. It was calculated that only about 3600 clinical diseases were associated with the epidemic, recognised retrospectively from the findings of the four sero-epidemiological surveys. Epidemiological data indicated that the excess clinical diseases caused by HAV concentrated in the southern counties of Hungary, which have been affected by the social and military activities between 1992 and 1994. Due to the decrease of subjects seropositive for HAV, sera from preselected or actively immunised donors will be required in the future and vaccination against HAV with killed virus is likely to be recommended for risk groups. Furthermore, health authorities might promote active immunisation of young children against HAV infection; for that, promotion of manufacturing combination vaccines of HAV/HBV/DPT or, for certain countries, HAV/DPT would be desirable.

[Newly discovered hepatitis viruses--do they cause hepatitis indeed?]

The paper reviews the available information on the newly discovered viruses originally supposed to cause post-transfusion hepatitis. GBV-C/Hepatitis G virus belongs to the Flaviviridae family, and can be transmitted parenterally like Hepatitis C virus. Its role in causing hepatitis or other diseases has not been proved yet. The other newly discovered viruses contain single-stranded circular DNA, with a wide range of sequence divergence. These viruses can be transmitted not only with blood and blood products but via fecal-oral route as well. They are unique among enterally transmitted viruses in the sense that the virus persists for years in the human body, therefore their genomes may be detected in the blood of the healthy population in high percentage. One of the genotypes of TTV is suspected to cause hepatitis. High TT virus load was found as an independent factor associated with the occurrence of hepatocellular carcinoma among patients with hepatitis C virus-related chronic liver disease. It is not clear yet, whether TTV-like minivirus and SEN virus cause any illnesses.

Alternate adenovirus type-pairs for a possible circumvention of host immune response to recombinant adenovirus vectors

With the help of monoclonal antibodies the existence of at least 18 different earlier not known intertype (IT) specific epitopes were demonstrated in different numbers and combinations on the hexons of different adenovirus serotypes. The IT specific epitopes play an important role in the experimental gene therapy and in the recombinant adenovirus vaccination because of the harmful immune response of the recipient organisms directed against the many different epitopes of the adenovirus vector. For the elimination of harmful effect the authors suggest the use of multiple vectors, each prepared from different adenovirus serotypes showing the loosest antigenic relationship to each other. The vectors would be used sequentially when second or multiple administration is needed. For this purpose the authors determined and described 31 such adenovirus type-pairs, which are probably the best alternates for sequential use in experimental gene therapy.

Taguchi optimisation of ELISA procedures

We propose a new method in the field of ELISA optimization using an experimental design called the Taguchi method. This can be used to compare the net effects of different conditions which can be both qualitative and quantitative in nature. The method reduces the effects of the interactions of the optimized variables making it possible to access the optimum conditions even in cases where there are large interactions between the variables of the assay. Furthermore, the proposed special assignment of factors makes it possible to calculate the biochemical parameters of the ELISA procedure carried out under optimum conditions. Thus, the calibration curve, the sensitivity of the optimum assay, the intra-assay and inter-assay variability can be estimated. The method is fast, accessing the results in one step, compared to the traditional, time-consuming 'one-step-at-a-time' method. We exemplify the procedure with a method to optimize the detection of ScFv (single chain fragment of variable) phages by ELISA. All the necessary calculations can be carried out by a spreadsheet program without any special statistical knowledge.

Interrelationship of viruses and cells. The cytopathic property of adenoviruses

The application of in vitro cell cultures in virus research has a great importance in studies on the interaction between virus and cell. A great number of the viruses causes characteristic degeneration in the infected cells, well visible in the light-microscope, and due to their cytopathic effect the existence of viruses became directly detectable. Based on characteristic changes even the serological type of virus can be determined in some cases. Thus the multilateral examination of the interaction between virus and host cell has immense importance both in virus research and in therapy.

Characterization of intertype specific epitopes on adenovirus hexons

The specification and differentiation of eighteen intertype specific (IT) epitopes of adenovirus hexons defined by monoclonal antibodies are given by two groups of hexon types: on which they are and on which they are not present. The close specificity relationship among some groups of epitopes determined by pairwise analysis according to their presence on the hexon types indicate that they could be continuous (sequential), overlapping or discontinuous (topographic) epitopes. Based on the identification of the hydrophilic regions and the localization of beta-turns sixteen IT epitope sites were predicted on human adenovirus (HAdV) type 2 and nineteen on HAdV-41 hexon's amino acid (aa) sequences beside the type and genus specific ones. The 16 predicted IT epitopes on HAdV-2 hexon show good coincidency with the 14 IT epitopes demonstrated with monoclonal antibodies (MAbs) on this hexon type. The predicted number of common epitopes between HAdV types 2 and 41 also corresponds well with the eight IT epitopes determined by MAbs, but the 17 predicted non-common epitopes indicate the possibility of the existence of more epitopes on these hexon types. The location of the predicted epitopes of HAdV-2 were determined by alignment of their sequence numbers on the three dimensional ribbon representation of the hexon subunit. Most of the predicted IT epitopes were found between the type and genus specific epitopes i.e. in the "upper" regions of pedestal domains P1 and P2 orientated toward the virion surface and in the "lower" part of loop 1 region orientated inside the virion. Two peptides representing potential IT epitopes were synthesized corresponding to residues 309-320 from the "lower" part of loop 1 and 399-408 from the "upper" part of P1 region of HAdV-2 hexon. Antibodies raised against the peptide-carrier conjugates recognized different purified native hexon types in ELISA.

Characterization of adenovirus hexons by their epitope composition

For the investigation of epitope composition of different adenovirus hexon types sixty-one mouse ascitic fluids containing monoclonal antibodies (MAbs) developed in three different panels were used. The distinction and marking of the different epitopes recognized by the MAbs were carried out by the determination of the composite cross-reactivity pattern, the titer and the correlation coefficient of all the 61 MAbs with 21 different hexon types representing all the six human subgenera, as well as different bovine and simian adenoviruses. The distinct epitopes were marked by two numbers referring the homologous hexon type to which the MAbs were directed and the serial number of the epitope specified by the different members of the given panel of the MAbs. The three panels of MAbs recognized 22 epitopes on the 21 hexon types among them a genus and three type specific ones and 18 different bi- and multilateral intertype (IT) specific epitopes that grouped adenoviruses within the genus, independently from the subgenus they belong to. Considering that the type specific epitope could be present only on the homologous hexon type, the largest number of the different epitopes distinguishable by the MAbs used could be 20 on the homologous hexon and 19 on the heterologous ones. It was found that the total number of IT specific epitopes on the hexons varied between 2 and 18. The distribution of the distinct specific epitopes on the different hexon types was different, as expected. The antigenic structure of the individual hexon types were characterized by the determination of their IT specific epitope spectrum. By pairwise analysis ten human hexon types formed three epitope clusters (types 4 and 19; types 8, 9, 9/13 and 10; as well as all types of subgenus C) showing identical epitope spectra. No clustering was found with human type 7, 12, 13, 18, 26, 27, 35 and 41, as well as with bovine and simian adenovirus hexons studied. However, they displayed a closer or looser antigenic relationship among each other and to members of the epitope clusters. The degree of antigenic relationship could be expressed by the similarity/dissimilarity percentage calculated from the number of the identical and different epitopes present on any two given hexon types.

Antigenic homogeneity among the adenovirus hexon types of subgenus C

Antigenic relationships of hexons of human adenovirus (Ad h) types 1, 2, 5 and 6 of subgenus C were studied with 61 monoclonal antibodies (MAbs) raised against human Ad h1, Ad h35 and bovine adenovirus 2. The reactivity pattern (RP) and the titers of the MAbs were determined in indirect ELISA. In previous experiments with hexons of different subgenera 49 MAbs displayed numerous different intertype specificities besides genus specific and type specific ones. With the four hexon types of subgenus C all MAbs gave identical RPs except the type specific ones. Data reveal the existence of a remarkable homogeneity in the antigenic structure among the hexon types of subgenus C defined by the presence of identical or closely related intertype specific epitopes on the surface of the hexons. The possible significance of the results in the experimental gene therapy is discussed.

Latex agglutination and adenoviruses. I. Detection of polyclonal antibodies by latex agglutination test

A latex agglutination (LA) test was developed for the detection and measurement of polyclonal anti-adenovirus antibodies. Latex particles, coated with purified hexon, penton or fibre antigens displayed specific agglutination with 21 rabbit immune sera directed against the different antigens and the complete virus of 10 human and 2 animal adenovirus types. The sensitivity of LA was compared to that of passive haemagglutination, complement fixation (CF) and immunodiffusion reactions. In experiments with immune sera as well as with human serum samples the sensitivity of LA test proved to be in the same range as that of CF test. Because of its easy and rapid performance (slide agglutination within 4 min) LA method may substitute for CF reaction in serological adenovirus diagnosis.

Aluminium levels in the blood plasma of persons working in the aluminium industry

Due to the exposure to alumina in the air, workers in the primary aluminium industry are expected to exhibit a higher aluminium exposure than the general population. The additional daily intake will be less than 20 mg. The determination of aluminium in blood plasma of electrolysis-workers by flameless atomic absorption spectrometry revealed levels before shift in the range of 20-30 μg/L compared to levels of less than 3 μg/L in a non-occupationally exposed group. These levels refer to work in old plants with unhooded pots. The plasma levels can rise up to 60 μg/L during the shift. A similar rapid change of the levels during work is seen in the urine values. Due to the delay in excretion the maximal values in the range of 5 μg/h are found four hours after cessation of work. It seems therefore that only preshift samples give a reliable measure of the body burden. Compared to the much higher levels in dialysis patients the observed values in aluminium workers are not considered to be of relevance to health.