Human substantia nigra in vitro as a bioassay for neurotrophic molecules of clinical significance.
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Biological Assay↗
Biomedical subjects
A Pizzuti
Publications and source records attributed to A Pizzuti.
Human homologue sequences to the Drosophila dishevelled segment-polarity gene are deleted in the DiGeorge syndrome.
DiGeorge syndrome (DGS) is a developmental defect of some of the neural crest derivatives. Most DGS patients show haploinsufficiency due to interstitial deletions of the proximal long arm of chromosome 22. Deletions of 22q11 have also been reported with patients with the velocardio-facial syndrome and familial conotruncal heart defects. It has been suggested that the wide phenotype spectrum associated with 22q11 monosomy is a consequence of contiguous-gene deletions. We report the isolation of human cDNAs homologous to the Drosophila dishevelled (dsh) segment-polarity gene. Sequences homologous to the 3' UTR of these transcripts (DVL-22) were positioned within the DGS critical region and were found to be deleted in DGS patients. Human DVL mRNAs are expressed in several fetal and adult tissues, including the thymus and, at high levels, the heart. Two transcripts, 3.2 and 5kb, were detected, in northern blot analysis, with different expression patterns in the surveyed tissues when different cDNAs were used. The isolated cDNAs exhibit high amino acid homology with the mouse and Xenopus Dvl-1 gene, the only other vertebrate dsh homologues so far isolated. The pivotal role of dsh in fly development suggests an analogous key function in vertebrate embryogenesis of its homologue genes. Since DGS may be due to perturbation of differentiation mechanisms at decisive embryological stages, a Dsh-like gene in the small-region overlap (SRO) might be a candidate for the pathogenesis of this disorder.
Adaptor Proteins, Signal Transducing↗
How many breaks do we need to CATCH on 22q11?
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Chromosome Deletion↗
Different expression of the myotonin protein kinase gene in discrete areas of human brain.
We have examined the myotonin protein kinase (MT-PK) gene expression in different human brain areas. Four different spliced forms, comprising exons 13 and 14, were identified and characterized. One form (MYOT-A), lacking the entire exon 13, had not been detected in other studies and it is likely to be a brain-specific transcript. Different brain areas show a specific transcription pattern. These results suggest that MT-PK may have specialized functions in different areas of central nervous system. Alterations of this complex expression pattern could be responsible for the mental status impairment observed in myotonic dystrophy patients.
Alternative Splicing↗
Survival motor neuron gene transcript analysis in muscles from spinal muscular atrophy patients.
We have identified and characterized four different mRNA isoforms of the survival motor neuron (SMN) gene from skeletal muscle of 9 SMA patients and 15 unaffected controls. These isoforms appear to be generated by combinatorial splicing of both exons 5 and 7 of the SMN telomeric and centromeric gene copies. The full-size and the truncated SMN-1b isoforms of the telomeric SMN copy are significantly reduced in muscle of SMA patients, irrespective of the disease types. Our results suggest that multiple RNA splicing is operative in the two SMN-related genes and that SMN-related polypeptides may be active in the muscle.
Alternative Splicing↗
Identification of multiple transcribed sequences from the spinal muscular atrophy region of human chromosome 5.
We report the isolation and characterization of novel expressed sequences from the spinal muscular atrophy (SMA) region on human chromosome 5q13. Based on the sequence homology studies these cDNAs were grouped in four classes, one of which shows extensive homologies with the beta-glucuronidase (BG) gene, differing in exon arrangement. The other cDNAs do not show any strong homology with known DNA sequences.
Base Sequence↗
Postzygotic instability of the myotonic dystrophy p[AGC] in repeat supported by larger expansions in muscle and reduced amplifications in sperm.
We have analysed the [AGC] expansion in leucocytes, muscle and sperm from 17 individuals affected by myotonic dystrophy (DM). Skeletal muscle showed a larger repeat number than leucocytes in the same patient. A similar degree of expansion was detected in differently affected muscles of a single patient. The germline mutation (< or = 350 repeats) was expanded in somatic cells of the progeny in all patients examined. Our results provide evidence of an early postzygotic instability of the [AGC] repeat in DM.
Adolescent↗
[Transesophageal echocardiography in patients with atrial fibrillation, candidates for cardioversion: usefulness and limitations].
BACKGROUND: Thromboembolic complications after electrical cardioversion (CV) of atrial fibrillation (AF) have been attributed to the dislodgment of preexistent left atrial thrombus during the resumption of atrial contraction. Transesophageal echocardiography (TEE) has been used to identify patients without thrombus, who potentially could undergo CV without anticoagulation. However, embolic events after CV in patients without evidence of thrombus on TEE have recently been reported. AIM OF THE STUDY: To evaluate if absence of thrombi or prethrombotic conditions such as spontaneous echo contrast or left atrial appendage disfunction can justify electrical CV without anticoagulant therapy. METHODS: Seventy-four patients with AF and candidates for CV underwent monoplane TEE. Patients were cardioverted without anticoagulation in case of: 1) absence of thrombus and/or spontaneous echocardiographic contrast and 2) good visualization of left atrial appendage, with a well defined peak blood flow velocity greater than 20 cm/sec. In all other cases, patients underwent anticoagulant therapy which started 3 weeks before CV and continued for 4 weeks afterwards. RESULTS: Forty-six patients, without thrombus or "prethrombotic" conditions, did not receive anticoagulation, while 28 followed traditional therapy with warfarin. Four patients with a thrombus in the left atrial appendage were identified: 1 died of cerebral embolism 3 days after the beginning of anticoagulation, in another one CV was definitely deferred because of the persistence of thrombus after 1 month of warfarin therapy. One patient, with left atrial appendage disfunction, died suddenly after 5 days of anticoagulation. Two patients reverted spontaneously in sinus rhythm. Two patients refused electrical CV. The remaining 67 patients underwent electrical CV which was successful in 56 of them. Cerebral embolism occurred 24 hours after CV in one patient who did not receive anticoagulation. Repeat TEE soon after embolism showed absence of thrombus or spontaneous echo contrast, but the presence of low flow velocity in the left atrial appendage. CONCLUSIONS: In patients in AF candidates for CV, exclusion of thrombi or prethrombotic conditions by TEE does not exclude the risk of thromboembolic events and the need for anticoagulant therapy. Left atrial appendage function can be stunned or impaired immediately after CV, favouring a thrombogenic milieu and subsequent embolic events. Therapeutic anticoagulation at the time of as well as after cardioversion is actually recommended.
Aged↗
Molecules with neurotrophic effects on the human developing mesencephalic dopaminergic neurons.
Parkinson's disease (PD) is characterized by the degeneration of the mesencephalic dopaminergic (mesDA) neurons innervating the striatum. Neurotrophic factor(s) that prevents the degeneration and increases the functional activity of the remaining mesDA neurons are of substantial clinical interest. The origin and development of mesDA neurons were characterized in the human mesencephalon from 5.0 to 12 Postconception (PC) weeks. Tyrosine Hydroxylase (TH) immunoreactive cells were first demonstrated at 5.5 PC weeks next to the ventricular zone. In primary culture, TH immunoreactive neurons represent 3 to 5% of the total cells at days 7 in vitro and basic Fibroblast growth factor (bFGF) was demonstrated to induce a significant increase of both TH immunoreactive cell number and TH enzymatic activity. This effect was mediated by proliferating glial fibrillary acidic protein immunoreactive cells. Nerve growth factor treatment did not have any appreciable effect. The effect of bFGF on TH positive cells described in this human bioassay is only a preliminary evidence that, if confirmed by experiments in vivo, may provide a starting rationale for investigating alternative strategies in the treatment of PD.
Cell Division↗
NGF-response of EGF-dependent progenitor cells obtained from human sympathetic ganglia.
Signalling molecules are thought to play a significant role in determining the fate of neural crest progenitor cells. The human sympathetic chain was identified at 6.5, 7.5, 8.2, 10.2 and 11.4 postconception (PC) weeks demonstrating low affinity nerve growth factor (NGF) receptors, and was processed for tissue culture. In the presence of epidermal growth factor (EGF), floating spheres of proliferating progenitor cells were developed in vitro. In the absence of EGF progenitor cells differentiated into tyrosine hydroxylase (TH)-immunoreactive neuronal and TH-negative flat cells. NGF treatment significantly increased neurite outgrowth and survival of TH-immunoreactive cells. The multipotent cells we isolated differ from previously reported sympathoadrenal progenitors in that they give rise to TH immunoreactive neurones precociously sensitive to NGF.
Cell Survival↗
Isolation of a new gene in the Friedreich ataxia candidate region on human chromosome 9 by cDNA direct selection.
The Friedreich ataxia (FRDA) locus is localized on chromosome 9q13 in an interval less than 1 Mb between markers D9S202/FR1 and FR5. We cloned the FRDA candidate region in YACs, and we started a systematic search for transcripts in this region using the cDNA selection approach. Several overlapping cDNA clones mapping near the telomeric end of the FRDA minimum genetic region were isolated. Zoo blot analysis demonstrated that these cDNAs are well conserved among different species. A transcript of 4.8 kb was identified by hybridization to a Northern blot containing human brain poly(A)+ RNA. Partial sequence of these clones showed 100% homology with a previously described anonymous brain cDNA (EST01251). A search for mutations of this gene in FRDA patients and carriers is in progress. No mutations have been found to date, but we have identified a DNA polymorphism. This polymorphism was nonrecombinant with the disease in a previously described FRDA pedigree in which a recombination had occurred with more telomeric markers.
Base Sequence↗
[Paradoxical embolism in a patient with aneurysm of the interatrial septum].
We report a case of pulmonary embolism complicated by paradoxical cerebral embolism in a patient with atrial septal aneurysm and patent foramen ovale. The patient was a 65-year-old obese woman, admitted because of sudden development of right-sided hemiplegia and dysarthria. In the few days before hospitalization she noted painful edema of the right leg and suffered from increasing dyspnea. Echo-Doppler examination of the venous bed confirmed the clinical suspicion of deep vein thrombosis. A pulmonary scan showed multiple perfusion defects in both lungs. On cerebral computerized tomography there were two non-haemorrhagic infarct zones. Contrast transesophageal echocardiography revealed a type II atrial septal aneurysm with right-to-left shunting through a patent foramen ovale. The patient was treated by warfarin, followed by implantation of a caval filter, with a good outcome. Paradoxical embolism may be more common than currently thought. In cases of pulmonary embolism, a careful check for clinical symptoms indicative of a possible paradoxical embolism should be performed and, consequently, a search for possible atrial septal aneurysm or patent foramen ovale.
Aged↗
Human elongation factor EF-1 beta: cloning and characterization of the EF1 beta 5a gene and assignment of EF-1 beta isoforms to chromosomes 2,5,15 and X.
We report here the isolation and characterization of a novel human elongation factor-1 beta (EF-1 beta) gene by cDNA selection from YAC mapping on chromosome 5q12-q14. This gene is specifically transcribed in fetal brain and in skeletal muscle and is characterized by a complete sequence homology with previously described EF-1 beta cDNAs. We also assigned the loci for three other EF-1 beta isoforms, to human chromosomes 2, 15 and X. The multiple chromosomal assignments of EF-1 beta loci demonstrates the genetic heterogeneity of human EF-1 beta peptides.
Base Sequence↗
Relationship between parental trinucleotide GCT repeat length and severity of myotonic dystrophy in offspring.
OBJECTIVE: To assess the relationship between the GCT repeat number in the myotonic dystrophy gene and the clinical phenotype and examine its predictive utility in prenatal testing. DESIGN: DNA from patients was examined for the length of the myotonic dystrophy GCT repeat region, using both Southern blot analysis and polymerase chain reaction. The results were compared with the clinical onset of disease, as well as with pregnancy outcomes. SETTING: Patient samples were referred to the Kleberg DNA Diagnostic Laboratory at the Baylor College of Medicine for DNA analysis by geneticists and genetic counselors (84%), neurologists (10%), and obstetricians and other specialists (6%). Clinical features including onset of disease and family pedigrees were determined by the referring centers. PATIENTS: A total of 241 patient samples from 118 families referred from primarily genetic or neurological centers for genetic linkage analysis or mutation analysis for myotonic dystrophy. This included 44 families referred for prenatal diagnosis. MAIN OUTCOME MEASURES: A relationship between myotonic dystrophy disease onset and length of the GCT repeat allele, parental origin of the disease allele, and results of prenatal diagnosis predictions of disease status were measured. RESULTS: There is a relationship between increasing repeat length and earlier clinical onset of disease. Essentially all (> 99%) myotonic mutations causing myotonic dystrophy are accounted for by GCT repeat amplification. Congenital myotonic dystrophy occurs with as few as 730 GCT repeats but only with alleles of maternal origin. Maternal GCT repeats were found as low as 75 (asymptomatic) that were amplified to result in a child with congenital myotonic dystrophy. Application of DNA diagnosis to 32 pregnancies provided an accurate method for identification of at-risk fetuses and allele enlargement. CONCLUSIONS: The GCT repeat in myotonic dystrophy is highly mutable. The triplet repeat amplification is highly specific for mutations involving the myotonin protein kinase gene accounting for myotonic dystrophy. The quantitation of triplet repeats can be more sensitive than physical, ophthalmologic, and electromyography examinations since the mutation can be detected in patients without evidence of myotonic dystrophy clinical findings. The length of the triplet expansion is influenced by the sex of the transmitting parent and is related to the clinical onset of disease features. Prenatal measurement of the GCT triplet repeat has utility for families with myotonic dystrophy risk since mutant and normal repeats are distinguishable and the length of mutant repeat alleles is associated with clinical severity. Thus, GCT triplet measurement provides a highly accurate means of detecting the myotonic dystrophy mutation in patients and offers a new reproductive option for families at risk for myotonic dystrophy.
Blotting, Southern↗
Decreased expression of myotonin-protein kinase messenger RNA and protein in adult form of myotonic dystrophy.
The myotonic dystrophy mutation has recently been identified; however, the molecular mechanism of the disease is still unknown. The sequence of the myotonin-protein kinase gene was determined, and messenger RNA spliced forms were identified in various tissues. Antisera were developed for analytical studies. Quantitative reverse transcription-polymerase chain reaction and radioimmunoassay were used to demonstrate that decreased levels of the messenger RNA and protein expression are associated with the adult form of myotonic dystrophy.
Adult↗
The myotonic dystrophy gene.
The myotonic dystrophy gene codes for a protein kinase and contains a repeated trinucleotide motif (adenine-guanine-cytosine [AGC]) in its transcribed sequence. The repeat is polymorphic in the general population, varying in size from five to 37 AGC units in normal alleles. Myotonic dystrophy patients show expansions of the repeated sequence from over 50 elements up to several thousand units. There is a positive correlation between repeat size and clinical severity. The direct analysis of the AGC repeat size allows an easy confirmation of the clinical diagnosis of myotonic dystrophy in difficult cases and for prenatal counseling.
Amino Acid Sequence↗
(CTG)n triplet mutation and phenotype manifestations in myotonic dystrophy patients.
A genotype-phenotype study based on the primary clinical features of adult myotonic dystrophy (DM) included 116 patients from 62 Italian pedigrees. A significant correlation between clinical severity and the number of repeats at the 3' untranslated region of the myotonin-protein kinase gene (MT-PK) was found. These results suggest that the CTG amplification is directly related to the myotonic dystrophy phenotype and provide important information on morbidity and prognosis in this disease.
Adolescent↗
[Cor triatriatum associated with inter-atrial defect: diagnosis by transesophageal echocardiography].
Cor triatriatum (CT) is a rare malformation consisting of a fibromuscolar membrane that subdivides the left atrium in a postero-superior (or accessory) chamber and an antero-inferior chamber (true left atrium, containing the left atrial appendage). In its classic form, the accessory chamber receives the pulmonary veins and communication with the left atrium is accomplished by way of one or more fenestrations in the membrane. The malformation is usually isolated, but in about one in four patients is associated with other congenital defects of a complex nature. We describe a case of CT associated with atrial septal defect, in which transthoracic echocardiography failed to document the existence of CT membrane, while this abnormality was clearly seen and defined by use of transesophageal echocardiography. The patient was a 26 year-old girl, presented at our outpatient clinic after an episode of palpitations and dyspnea, which lasted for two hours. She suffered of mild dyspnea on exertion during the last three months. Physical examination revealed the typical findings of an atrial septal defect (ASD), and the electrocardiogram revealed right bundle branch block. The two-dimensional echocardiography disclosed an ostium secundum ASD with left to right shunt; dilatation of the right cavities; paradoxical movement of the interventricular septum. A small linear echo originating from the lateral wall of the left atrium, with no evidence of turbulent flow on pulsed wave Doppler and color flow examination, was interpreted as an artifact. Transesophageal echocardiography clearly visualized a tense, bulging membrane separating left atrium into two chambers.(ABSTRACT TRUNCATED AT 250 WORDS)
Abnormalities, Multiple↗