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At least 235 records · Page 13Linked to original sources
PubMed1991

A new enzyme immunoassay for a solid Chinese crude drug, pinellia tuber.

A new immunoassay for a solid Chinese crude drug was studied. An antiserum specific for Pinellia tuber was elicited in two rabbits. Using the antiserum and powdered Pinellia tuber-coated microtiter plate as the immunological reagents, and beta-D-galactosidase-labeled goat anti-rabbit immunoglobulin G (IgG) as the tracer, a new enzyme immunoassay for a solid Pinellia tuber with a working range between 0.1 and 1000 micrograms/ml was developed. The assay was specific for a solid Pinellia tuber and showed low cross-reaction values on other Chinese crude drugs and the extract of Pinellia tuber. The specificity of the assay was compared with the selected antibody enzyme immunoassay (SAEIA) for the extract of Pinellia tuber recently developed. Both methods utilized the same immunological reagents such as the serum and the enzyme-labeled goat anti-rabbit IgG, and the only difference between them was the solid-phase antigen used. The assay results of several antigens determined by them were quite different, showing that selective measurements of different antigens, either solid or the extract of Pinellia tuber, were possible using the same antiserum, when the tracing reaction in the immunoassay was adequately selected.

Drugs, Chinese Herbal↗
PubMed2005

Structural diversity and differential transcription of the patatin multicopy gene family during potato tuber development.

The patatin multicopy gene family encodes the major storage protein in potato tubers and is organized as a single cluster in the potato genome. We sequenced a 154-kb bacterial artificial chromosome (BAC) clone containing a portion of the patatin gene cluster. Two putatively functional patatin genes were found in this BAC. These two genes are embedded within arrays of patatin pseudogenes. Using a chromatin immunoprecipitation method we demonstrate that the dramatic increase of patatin gene expression during the transition from stolons to tubers coincides with an increase of histone H4 lysine acetylation. We used 3' rapid amplification of cDNA ends to profile expression of different patatin genes during tuber development. The profiling results revealed differential expression patterns of specific patatin gene groups throughout six different stages of tuber development. One group of patatin gene transcripts, designated patatin gene group A, was found to be the most abundant group during all stages of tuber development. Other patatin gene groups, with a 48-bp insertion in the 3'-untranslated region, are not expressed in stolons but display a gradual increase in expression level following the onset of tuberization. These results demonstrate that the patatin genes exhibit alterations in chromatin state and differential transcriptional regulation during the developmental transition from stolons into tubers, in which there is an increased demand for protein storage.

3' Untranslated Regions↗
PubMed2001

[The influence of genotype on the effects of impact damage and light exposure on the accumulation of glycoalkaloids in potato tubers].

The experiment was carried out in 1999 with 24 Polish and 23 West European cultivars of potato tubers. The tubers were analysed for TGA content after 3 months of dark storage conditions in store-house (8 degrees C). 20 tubers of every cultivar were damaged and placed for a week to dark and under 15 W fluorescent lamps--13 mumol m-2 sec(-1)--equivalent to light in supermarkets. Glycoalkaloids content was determined with Bergers (1980) method. Tubers which had been damaged and exposed for a week to fluorescent light had two fold higher levels of TGA, than undamaged tubers stored at dark. It was found that content of glycoalkaloids in potato tubers and the increase of TGA content due to damage and light exposure depended on genotype. It was higher in varieties with higher level of these compounds, for example: Peppo, Albatros, Columbus and Santana (above 200 mg/kg fresh weight)--tab. I. The smaller increase occurred in tubers of varieties with low content of TGA: Polish--Irga, Grot, Baszta, Tokaj and West European--Satina, Ditta Gloria, Victoria--tab. I, II. Therefore it is important to breed new cultivars with low content of TGA.

Agriculture↗
PubMed2005

[Effects of antisense acid invertase gene on reducing sugar and starch contents of potato (Solanum tuberosum L.) tuber stored at low temperature].

Two transgenic potato lines with antisense AcInv gene and the non-transgenic varieties were used to test the reducing sugar and starch contents. The results indicated that the reducing sugar content increased and total starch content decreased in all samples after tubers were stored at 4 degrees C for 40 d. The reducing sugar content in tubers of transgenic line "Anti-AcInv Atlantic" and "Anti-AcInv Gannongshu No.2" were lower about 23% and 18% than those of Atlantic and Gannongshu No.2 (Table 1). The total starch and the amylopectin were also decreased by 1% and 1.3% in "Anti-AcInv Atlantic" and 1.4% and 1.7% in "Anti-AcInv Gannongshu No.2" respectively (Table 2). The proportions of amylose and amylopectin were lower in the transgenic lines than the non-transgenic varieties (Figs. 1 and 2). It was only 0.29 for "Anti-AcInv Atlantic" and 0.38 for "Anti-AcInv Gannongshu No.2". Meanwhile, there are fewer dark blue starch particles in transgenic tuber, which is less than in tuber of the non-transgenic varieties by paraffin-cut section method (Fig. 3). After the tubers were transferred to the storage temperature 15-17 degrees C for 20 d, the reducing sugar contents in tubers of the two transgenic lines were significantly lower than that of non-transgenic varieties. It was 0.23% for "Anti-AcInv Atlantic" and 0.24% for "Anti-AcInv Gannongshu No.2" (Table 1). It is suggested that the trans-antisense AcInv gene in the transgenic potato down-regulates the AcInv gene expression after the tubers were stored under low temperature.

Amylopectin↗
PubMed1997

Tuberin immunohistochemistry in brain, kidneys and heart with or without tuberous sclerosis.

We have studied immunohistochemically the expression of tuberin, the protein product of the TSC2 gene, in cerebral, renal and cardiac tissues obtained from patients with tuberous sclerosis and from control patients. Tuberin immunoreactivity was moderate to strong in neurons and reactive astrocytes of control brains, but was reduced in brains with tuberous sclerosis. Staining intensity of abnormal giant cells varied from negative to moderate in cortical tubers, subependymal nodules and subependymal giant cell astrocytomas. In control kidneys, uriniferous and collecting tubules showed positive immunoreactivity, whereas a focal decrease in their staining intensity was noted in kidneys with tuberous sclerosis. Renal angiomyolipomas were negative for tuberin. In the heart, cardiac muscles in both control and tuberous sclerosis patients were strongly immunoreactive. Cardiac rhabdomyomas in the latter were stained less intensely. These results provide histological evidence for the loss of tuberin in tuberous sclerosis tissues, which is associated with the development of hamartomas in an organ-specific manner.

Adolescent↗
PubMed1997

The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis.

Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.

Amino Acid Sequence↗
PubMed2004

Insulin signaling pathways in cortical dysplasia and TSC-tubers: tissue microarray analysis.

To evaluate the possible roles of the Akt/PKB-mTOR-p70S6K-S6 and cap-dependent translation (eIF4G) pathways in the pathogenesis of tuberous sclerosis complex (TSC)-associated cortical tubers and focal cortical dysplasia (FCD), we performed qualitative and semiquantitative immunohistochemical evaluation on surgically resected corticectomy specimens to detect phosphorylated molecules as activated downstream targets of the signaling pathways. A tissue microarray paraffin block was constructed from 63 archival specimens of surgically resected TSC tubers, FCDs with balloon cells, cortical dysplasia without balloon cells, and histologically normal-appearing neocortex obtained from cases with Rasmussen encephalitis, cystic-gliotic encephalopathy, and temporal lobe epilepsy. Abnormal neuroglial cells were positive for phospho-S6 and phospho-eIF4G with various staining intensities in FCDs and TSC tubers. Both proteins were much less abundantly expressed in normal-appearing neocortex. Phospho-mTOR expression was observed in neurons in all groups. The expression of phospho-S6 and phospho-eIF4G was associated with dysplastic lesions (p < 0.05), and the cytoplasmic phospho-p70S6K expression was most specific for and abundant in TSC tubers and much less prominent in other groups (p < 0.01). These results suggest that constitutive activation of cytoplasmic p70S6K plays a pivotal role in the pathogenesis of TSC tubers and that FCDs possess a distinct mechanism for activation of S6 and eIF4G.

Adolescent↗
PubMed2006

Proteomic analysis of the potato tuber life cycle.

The tuber of potato (Solanum tuberosum) is commonly used as a model for underground storage organs. In this study, changes in the proteome were followed from tuberization, through tuber development and storage into the sprouting phase. Data interrogation using principal component analysis was able to clearly discriminate between the various stages of the tuber life cycle. Moreover, five well-defined protein expression patterns were found by hierarchical clustering. Altogether 150 proteins showing highly significant differences in abundance between specific stages in the life cycle were highlighted; 59 of these were identified. In addition, 50 proteins with smaller changes in abundance were identified, including several novel proteins. Most noticeably, the development process was characterized by the accumulation of the major storage protein patatin isoforms and enzymes involved in disease and defense reactions. Furthermore, enzymes involved in carbohydrate and energy metabolism and protein processing were associated with development but decreased during tuber maturation. These results represent the first comprehensive picture of many proteins involved in the tuber development and physiology.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1993

Cortical tubers demonstrate reduced immunoreactivity for synapsin I.

To evaluate the effects of tuberous sclerosis (TS) on cortical synaptic organization, we analyzed synaptic densities within cortical tubers from the brains of two TS patients using a polyclonal antibody directed against synapsin I, a synaptic terminal-specific protein. The synaptic densities of the tubers and adjacent histologically normal cortex were obtained by determining optical densities using an IBAS (Zeiss) image analysis system. The tubers showed abnormally low levels of synapsin I compared with the normal cortex. The data suggest that cortical tubers do not contain a normal complement of synapses. This may reflect focal underdevelopment of normal cortical-cortical connections. Altered afferent cortical projections may also contribute to synaptic loss in cortical tubers.

Cerebral Cortex↗
PubMed2006

Tuberous sclerosis with open lipped schizencephaly.

Tuberous sclerosis is a multisystem disorder that is transmitted in an autosomal dominant fashion. It affects approximately 1 in 10,000 live births. A growing body of evidence implicates a defect of cell maturation and migration in the pathogenesis of many of the lesions in tuberous sclerosis affecting the central nervous system. There have been numerous case reports of various abnormalities of neuronal migration associated with tuberous sclerosis. To our knowledge, there has only been one case of schizencephaly reported in a patient with tuberous sclerosis. The present report describes a male with tuberous sclerosis and an extensive open lipped schizencephalic cleft affecting his right frontoparietal lobe. This case supports the hypothesis that the cerebral lesions in tuberous sclerosis are secondary to a defect in neuronal maturation and migration.

Abnormalities, Multiple↗
PubMed1989

Tuberous sclerosis: aberrant proline sensitivity of skin fibroblasts.

Cultured skin fibroblasts from patients with tuberous sclerosis were analyzed as to their sensitivities to proline, glutamic acid and arginine, and their analogues by means of a cell growth study. A difference was observed between tuberous sclerosis and normal cells when proline was added. Skin fibroblasts derived from normal-appearing skin of tuberous sclerosis patients exhibited sensitivity to proline. Skin fibroblasts derived from tumorous skin of tuberous sclerosis patients exhibited resistance to proline in the cell growth study and was found to be rather sensitive to proline in a colony formation study. This aberrant sensitivity to proline of tuberous sclerosis cells may indicate abnormal proline metabolism in tuberous sclerosis patients.

Arginine↗
PubMed2001

Vagal nerve stimulation in tuberous sclerosis complex patients.

This is an open-label, retrospective, multicenter study to determine the outcome of intermittent stimulation of the left vagal nerve in children with tuberous sclerosis complex and medically refractory epilepsy. The records of all children treated with vagal nerve stimulation were reviewed in five pediatric epilepsy centers to locate those with tuberous sclerosis complex who had been treated with vagal nerve stimulation for at least 6 months. These patients were compared with (1) a series of patients obtained from the literature, (2) 10 similar control patients with epilepsy obtained from a registry of patients receiving vagal nerve stimulation, and (3) four published series of tuberous sclerosis complex patients whose epilepsy was surgically managed. Ten tuberous sclerosis complex patients with medically refractory epilepsy treated with vagal nerve stimulation were found. Nine experienced at least a 50% reduction in seizure frequency, and half had a 90% or greater reduction in seizure frequency. No adverse events were encountered. Comparison with published and registry patients revealed improved seizure control in the tuberous sclerosis complex patients. Comparison with the group undergoing seizure surgery demonstrated improved outcomes after surgery. Vagal nerve stimulation appears to be an effective and well-tolerated adjunctive therapy in patients with tuberous sclerosis complex and seizures refractory to medical therapy. Resective surgery has a better prospect for improved seizure control.

Adolescent↗
PubMed2002

Tuberous sclerosis complex: a review of neurological aspects.

Tuberous sclerosis complex is characterized by hamartomatous lesions involving skin, brain, kidneys, eyes and heart. Pathologically, tuberous sclerosis is a disorder of cell migration, proliferation and differentiation. Cell lineage and cell migration disorders in the developing cortex of tuberous sclerosis complex patients might produce very different neurological phenotypes including epilepsy, cognitive impairment and autism. Cortical tubers constitute the hallmark of the disease and are pathognomonic of cerebral tuberous sclerosis. Epilepsy is the most common neurological feature, occurring in 96% of patients. Seizures often begin in the first months of life and are frequently severe and intractable. The treatment of seizures has recently benefited from the advent of the new anti-epileptic drugs. Selected drug-resistant patients with tuberous sclerosis complex could be considered for surgical treatment. Clear localization of the most active epileptogenic focus and the zone of the cortical abnormality may lead to tuberectomy and improved seizure control in selective drug-resistant patients. The finding of multiple areas of cerebral involvement should not automatically preclude epilepsy surgery in a child with intractable seizures and a well defined seizure origin.

Anticonvulsants↗
PubMed2006

Current management for epilepsy in tuberous sclerosis complex.

PURPOSE OF REVIEW: This article reviews the most significant advances in the field of epilepsy associated with tuberous sclerosis complex, with emphasis on new advances in the knowledge of the pathophysiological mechanisms of epileptogenicity, progress in identifying the epileptogenic zone, and the rationale for surgical management in individuals with intractable seizures. RECENT FINDINGS: Advances in our understanding of the mechanisms and genetics underlying infantile spasms and catastrophic epilepsy associated with tuberous sclerosis complex may facilitate more effective interventions. Early effective seizure control could significantly reduce the adverse developmental effects of chronic epilepsy in tuberous sclerosis. Vigabatrin is the first choice in the short-term treatment of infantile spasms. Some individuals, however, develop seizures that remain highly intractable. The factors that influence the intractability of epilepsy associated with tuberous sclerosis complex remain poorly understood. Multimodality neuroimaging has improved detection of epileptogenic foci, allowing an increased number of individuals to be evaluated for resective surgery. Epilepsy surgery is often associated with significant improvement of the neurologic outcome. SUMMARY: Epilepsy in tuberous sclerosis seems to arise from the interaction between multiple areas, all of which have increased excitability and reduced inhibition. Understanding the mechanisms of epileptogenesis might increase the availability of development of a more specific and efficacious treatment. New evidence suggests that it is possible to noninvasively identify children with tuberous sclerosis who are highly likely to become seizure free following surgical treatment.

Animals↗
PubMed2006

Magnetoencephalography in patients with tuberous sclerosis and localization-related epilepsy.

PURPOSE: To clarify the usefulness of magnetoencephalography (MEG) for diagnosis of the spatial relations between spike foci and suspicious epileptogenic tubers on MRI in patients with tuberous sclerosis (TS) and to compare MEG spike foci with single-photon emission computed tomography (SPECT) findings. METHODS: We analyzed magnetic fields of epileptic spike discharges in 15 patients with TS and localization-related epilepsy (LRE) by using MEG (a whole-head 204-channel magnetometer system). We investigated the spatial relation between the equivalent current dipoles (ECDs) of interictal spike discharges and visible cortical tubers on MRI. We also compared results of MEG and MRI with SPECT findings. RESULTS: MEG detected a cluster of ECDs around one cortical tuber in six of 15 patients and clusters of ECDs around two cortical tubers in five patients. Interictal SPECT was disappointing in detection of epileptic foci in TS. However, MEG spike foci showed spatial consistency with ictal hyperperfusion areas in two patients. Three patients with single ECD clusters underwent surgical treatment: two have been seizure free, and one has obtained seizure reduction of >90%. CONCLUSIONS: ECDs were located around visible tuber nodules. MEG enabled precise localization of the epileptic foci and provided crucial information for surgical treatment in patients with TS and partial epilepsy. TS patients showing a single ECD cluster on MEG may be appropriate candidates for surgical treatment.

Adolescent↗
PubMed1989

Cerebral tuberous sclerosis: MR imaging.

Nineteen patients with a clinical diagnosis of tuberous sclerosis were examined with high-field-strength magnetic resonance (MR) imaging. Their ages ranged from 6 months to 12 years. In 17 cases, the MR examinations showed both subependymal nodules and multiple peripheral gyral lesions consistent with cortical tubers. Cortical tubers were more frequently demonstrated on spin-echo images obtained with a long repetition time (TR). Because the signal abnormality was located predominantly in the subcortical portion of the tubers, the terms "gyral core" and "sulcal island" were used to describe the patterns noted at MR imaging. Subependymal nodules were best seen on inversion-recovery or short TR spin-echo images, although hypointensity within the nodules consistent with calcification was present in 14 patients and was most evident on long TR spin-echo images. Computed tomographic (CT) scans that had been obtained within 3 years of MR images were available for 13 patients. Intracranial calcification was more accurately diagnosed with CT. However, MR imaging is more sensitive than CT in the detection of gyral tubers and, thus, may be better for screening family members and others in whom tuberous sclerosis is a possibility.

Brain↗
PubMedDate not supplied

CD44 expression in tuberous sclerosis.

CD44, a cell adhesion molecule, mediates cell-cell and cell-matrix interactions. In the central nervous system, CD44 is expressed in astrocytic processes, predominantly in white matter and subpial regions, suggesting its involvement in the maintenance of a stable central nervous system cytoarchitecture. In this study, we investigated immunohistochemically the expression of CD44 and glial fibrillary acidic protein in neurosurgically resected specimens of patients with or without tuberous sclerosis. In controls, CD44 immunoreactivity was noted in the processes of astrocytes close to blood vessels and subpial cortex. Glial fibrillary acidic protein immunoreactivity was noted in both cell bodies and cytoplasmic processes of astrocytes in white matter. In tubers, CD44 antigen was also noted in the processes of astrocytes close to blood vessels and pial surface, and in abundance in the network of astrocyte processes. Moreover, CD44 antigen showed immunoreactive halos around balloon cells in tubers and around tumor cells in subependymal lesions. Glial fibrillary acidic protein antigen was noted in both cell bodies and cytoplasmic processes of some balloon cells in tubers, but not in tumor cells. In Western blot analyses, the CD44 immunoreactive band was more intense in tubers or subependymal giant-cell tumors than in control tissue. This increase in CD44 antigen seemed to correlate with the degree of astrogliosis. Immunoreactivity surrounding the cell surfaces of balloon or tumor cells suggests that the clustering of these cells may be due to the expression of CD44. Glial fibrillary acidic protein immunoreactive band was detected in tubers, but not in subependymal giant cell tumors.

Adolescent↗
PubMed2004

Autism and tuberous sclerosis.

The co-occurrence of autism spectrum disorder and tuberous sclerosis complex has been recognized for decades. The prevalence of tuberous sclerosis complex in the autism spectrum disorder population is 1 to 4%, whereas features of autism spectrum disorder are present in 25 to 50% of individuals with tuberous sclerosis complex. The underlying reason for this association might be a nonspecific disruption of brain function owing to tuberous sclerosis complex, including tuber location, seizures and their effect on brain development, cognitive impairment, a disturbance in brain development in regions associated with autism spectrum disorder, or, less likely, a linkage between a TSC gene and an autism susceptibility gene. Awareness of the relationship between autism spectrum disorder and tuberous sclerosis complex is important during the evaluation of individuals with either disorder. Better delineation of the association and its causative factors is needed for the development of possible interventions.

Autistic Disorder↗