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Biomedical subjects

E A Thiele

Publications and source records attributed to E A Thiele.

15 recordsLinked to original sources

Renal manifestations of tuberous sclerosis complex: Incidence, prognosis, and predictive factors.

Tuberous sclerosis complex is a genetic disorder characterized by hamartomatous lesions in multiple organs, frequently involving the kidney. We conducted a retrospective review of the clinical and radiographic records of 167 patients with tuberous sclerosis to determine the frequency of renal disease, the likelihood of significant renal morbidity, and the effects of genotype (TSC1 vs TSC2) and gender on renal phenotype. Renal lesions were seen in 57.5% of patients. Of these, angiomyolipoma (AML) occurred in 85.4%, cysts in 44.8%, and renal cell carcinoma in 4.2%. Both AML and cysts were significantly more common and more numerous in TSC2 than in TSC1. AML was significantly more common in female than in male patients, but cysts showed no correlation with gender. Eleven patients developed renal abnormalities during their care in this practice at an average age of onset of 11.3 years (range 3.8-23 years). The frequency and number of renal lesions were positively correlated with age. Interventions, including arterial embolization and nephrectomy, were performed in 11 (6.6%) patients. Among female patients with lymphangioleiomyomatosis, renal AML was universally present. Our findings confirm a high rate of renal involvement; a low rate of serious complications; significant associations between renal involvement, genotype, and gender; and a significant association between renal and pulmonary involvement in female patients.

Adolescent↗

The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients.

OBJECTIVE: To evaluate the sensitivity of a simultaneous whole-head 306-channel magnetoencephalography (MEG)/70-electrode EEG recording to detect interictal epileptiform activity (IED) in a prospective, consecutive cohort of patients with medically refractory epilepsy that were considered candidates for epilepsy surgery. METHODS: Seventy patients were prospectively evaluated by simultaneously recorded MEG/EEG. All patients were surgical candidates or were considered for invasive EEG monitoring and had undergone an extensive presurgical evaluation at a tertiary epilepsy center. MEG and EEG raw traces were analysed individually by two independent reviewers. RESULTS: MEG data could not be evaluated due to excessive magnetic artefacts in three patients (4%). In the remaining 67 patients, the overall sensitivity to detect IED was 72% (48/67 patients) for MEG and 61% for EEG (41/67 patients) analysing the raw data. In 13% (9/67 patients), MEG-only IED were recorded, whereas in 3% (2/67 patients) EEG-only IED were recorded. The combined sensitivity was 75% (50/67 patients). CONCLUSION: Three hundred and six-channel MEG has a similarly high sensitivity to record IED as EEG and appears to be complementary. In one-third of the EEG-negative patients, MEG can be expected to record IED, especially in the case of lateral neocortical epilepsy and/or cortical dysplasia.

Adolescent↗

Epilepsy in children and adolescents.

Epilepsy is common in the pediatric population and can significantly affect the health and quality of life of the child and family. There are many causes of childhood seizures and many forms of treatment, including pharmacologic and surgical modalities. Psychiatric disease occurs with higher incidence in children with epilepsy, and psychiatric disease in children also must be differentiated from epilepsy. Many medications are used to treat epilepsy and psychiatric disease, all of which interact with each other pharmacodynamically, as well as acting on the clinical manifestations of the disorders. These factors, and the complicated interface between epilepsy and psychiatry, must be considered in the successful management of children with epilepsy.

Adolescent↗

Myelin basic protein reactive Th2 T cells are found in acute disseminated encephalomyelitis.

Acute disseminated encephalomyelitis (ADEM), a postinfectious illness of the central nervous system (CNS), is thought to be an autoimmune disease. Here, we characterized the cytokines secreted by myelin-reactive T cells generated from patients with ADEM. The frequency of MBP-reactive T cell lines was ten-fold higher in patients with ADEM compared to patients with encephalitis and normal subjects. Whereas there was no significant IFN-gamma secretion, the predominant cytokine secreted by MBP-reactive T cell lines was IL-4 in patients with ADEM. In contrast, IL-4 secretion was only rarely detected in the controls. The presence of high frequencies of MBP-reactive IL-4 secreting T cells in subjects with ADEM during their recovery phase may be similar to myelin reactive IL-4 secreting T cells observed during the spontaneous recovery of animals with EAE.

Antibodies, Viral↗

Nerve growth factor activates extracellular signal-regulated kinase and p38 mitogen-activated protein kinase pathways to stimulate CREB serine 133 phosphorylation.

The mechanisms by which growth factor-induced signals are propagated to the nucleus, leading to the activation of the transcription factor CREB, have been characterized. Nerve growth factor (NGF) was found to activate multiple signaling pathways that mediate the phosphorylation of CREB at the critical regulatory site, serine 133 (Ser-133). NGF activates the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs), which in turn activate the pp90 ribosomal S6 kinase (RSK) family of Ser/Thr kinases, all three members of which were found to catalyze CREB Ser-133 phosphorylation in vitro and in vivo. In addition to the ERK/RSK pathway, we found that NGF activated the p38 MAPK and its downstream effector, MAPK-activated protein kinase 2 (MAPKAP kinase 2), resulting in phosphorylation of CREB at Ser-133. Inhibition of either the ERK/RSK or the p38/MAPKAP kinase 2 pathway only partially blocked NGF-induced CREB Ser-133 phosphorylation, suggesting that either pathway alone is sufficient for coupling the NGF signal to CREB activation. However, inhibition of both the ERK/RSK and the p38/MAPKAP kinase 2 pathways completely abolished NGF-induced CREB Ser-133 phosphorylation. These findings indicate that NGF activates two distinct MAPK pathways, both of which contribute to the phosphorylation of the transcription factor CREB and the activation of immediate-early genes.

Animals↗

Electroencephalogram and clinical focalities in juvenile myoclonic epilepsy.

Partial seizures and asymmetric abnormalities seen on electroencephalogram (EEG) are infrequent in juvenile myoclonic epilepsy, but when present, can lead to a misdiagnosis of partial seizures. We report four patients with juvenile myoclonic epilepsy who had generalized spike or polyspike and wave discharges on EEG in addition to clinical and EEG evidence of focality. The clinical course and response to therapy was similar to that in typical juvenile myoclonic epilepsy.

Adolescent↗

Effect of secretagogues on components of the secretory system in AtT-20 cells.

The mouse corticotrope tumor cell line AtT-20/D16v was used to investigate the effects of chronic treatment with various secretagogues on individual components of the secretory pathway. Secretagogues acting in part through receptors linked to guanine nucleotide-binding regulatory proteins [CRF and somatostatin (SS)] and agents by-passing membrane receptors (phorbol myristate acetate and dexamethasone) were examined. Effects on the secretory product were evaluated by measuring levels of pro-ACTH/endorphin mRNA and hormone secretion. Effects on posttranslational processing enzymes were evaluated by measuring levels of the mRNAs encoding carboxypeptidase-E and peptidyl-glycine-alpha-amidating monooxygenase (PAM); cellular levels of PAM activity were also measured. The mRNAs encoding the G-proteins in AtT-20 cells were identified, and secretagogue effects on the G-protein signal transduction system were evaluated by measuring levels of the mRNAs encoding (alpha s, alpha)i2, and beta 2. No single parameter adequately characterizes the regulatory state of the complex secretory apparatus. Although levels of pro-ACTH/endorphin (PAE) mRNA accurately reflected hormone secretion after chronic CRF or dexamethasone treatment, chronic SS treatment elevated PAE mRNA levels in the face of reduced hormone secretion. Levels of PAM mRNA generally changed in parallel with levels of PAE mRNA; in contrast, levels of carboxypeptidase-E mRNA were unaffected by any of the secretagogues tested. Secretagogues acting through distinct G-proteins (CRF and SS) as well as dexamethasone brought about a coordinate increase in the level of the mRNAs encoding the three G-protein subunits examined. Treatment with phorbol myristate acetate caused a slight decrease in the levels of the G-protein subunit mRNAs.

Animals↗

Tissue-specific regulation of peptidyl-glycine alpha-amidating monooxygenase expression.

Peptidyl-glycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) is present in a variety of tissues, where it plays a vital role in the processing of numerous peptide substrates, often conferring bioactivity. PAM is present in high amounts in heart atrial myocytes and the pituitary gland, where activity is present in both soluble and membrane forms. We used AtT-20 cells, a mouse corticotrope tumor cell line, and primary heart atrial cultures to establish the occurrence of tissue-specific regulation of PAM expression. In the AtT-20 cells, PAM expression is regulated in parallel with the source of its peptide substrate, pro-ACTH/endorphin. PAM mRNA levels are increased to 132 +/- 5% of control values by treatment with (Bu)2-cAMP and decreased to 55 +/- 7% of control values by treatment with dexamethasone. Treatment with (Bu)2cAMP decreases PAM specific activity in the AtT-20 cells to 68 +/- 4% of the control value, presumably due to secretion of enzyme from the cells; dexamethasone treatment decreases PAM specific activity to 57 +/- 1% of the control value. In contrast, in heart atrial cultures, dexamethasone stimulates PAM expression. In atrial cultures exposed to dexamethasone for 48 h, PAM mRNA and PAM specific activity are elevated to 230 +/- 50% and 220 +/- 20% of control values, respectively; secretion of PAM activity is increased to 230% of the control value. As for AtT-20 cells, treatment of atrial cultures with (Bu)2cAMP increases PAM mRNA levels. Thus, PAM expression is regulated in a tissue-specific manner by dexamethasone in the two tissues examined. In AtT-20 cells, time-course studies and studies with cycloheximide indicate that dexamethasone exerts its effects on PAM mRNA levels by an indirect mechanism involving protein synthesis.

Animals↗

Structure of the precursor to an enzyme mediating COOH-terminal amidation in peptide biosynthesis.

Many bioactive peptides terminate with an amino acid alpha-amide at their COOH terminus. The enzyme responsible for this essential posttranslational modification is known as peptidyl-glycine alpha-amidating monooxygenase or PAM. We identified cDNAs encoding the enzyme by using antibodies to screen a bovine intermediate pituitary lambda gt11 expression library. Antibodies to a beta-galactosidase/PAM fusion protein removed PAM activity from bovine pituitary homogenates. The 108,207 dalton protein predicted by the complete cDNA is approximately twice the size of purified PAM. An NH2-terminal signal sequence and short propeptide precede the NH2 terminus of purified PAM. The sequences of several PAM cyanogen bromide peptides were localized in the NH2-terminal half of the predicted protein. The cDNA encodes an additional 430 amino acid intragranular domain followed by a putative membrane spanning domain and a hydrophilic cytoplasmic domain. The forms of PAM purified from bovine neurointermediate pituitary may be generated by endoproteolytic cleavage at a subset of the 10 pairs of basic amino acids in the precursor. High levels of PAM mRNA were found in bovine pituitary and cerebral cortex. In corticotropic tumor cells, levels of PAM mRNA and pro-ACTH/endorphin mRNA were regulated in parallel by glucocorticoids and CRF.

Amides↗

A rat brain isozyme of angiotensin-converting enzyme. Unique specificity for amidated peptide substrates.

We have purified angiotensin-converting enzyme (ACE, EC 3.4.15.1) from rat brain corpus striatum and rat lung. The brain enzyme has Mr 165,000 by sodium dodecyl sulfate gel electrophoresis, whereas the lung enzyme is 175,000. This difference is not an artifact of preparation since mixture of the two tissues prior to purification results in isolation of two proteins with Mr 165,000 and 175,000. Separation of tryptic fragments of 125I-labeled lung and brain ACE by reverse-phase chromatography yields distinct but similar patterns. No differences between the native enzymes are detected in dansyl-tripeptide cleavage specificity, inhibitor profile, immunological properties, sucrose gradient sedimentation, or gel filtration of ACE from the two tissues. However, lung and brain ACE can be differentiated in their ability to cleave amidated peptides. Both lung and brain ACE cleave Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2 (substance P) via two pathways. In one pathway, ACE first releases Gly-Leu-Met-NH2 and then dipeptides sequentially from the carboxyl terminus. The other first produces Leu-Met-NH2, and then releases dipeptides to leave substance P 1-5. Lung ACE favors initial tripeptide release 3:1, while the striatal enzyme acts via the two pathways to a similar extent. Lung and striatal ACE also differ in their ability to degrade other amidated peptides. His-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met-NH2 (substance K) and bombesin are degraded by striatal but not lung ACE. Physalaemin and luteinizing hormone-releasing hormone are cleaved by both enzymes, while eledoisin, kassinin, thyrotropin-releasing hormone, and substance P 5-11 are not cleaved by either enzyme. Physalaemin is degraded more rapidly by the lung enzyme. The coincidence of an ACE isozyme with substance P and substance K in the descending striatonigral pathway and the unique ability of this isozyme to cleave substance P and substance K suggest that one or both of these peptides is a physiological substrate for striatonigral ACE.

Amino Acid Sequence↗

Substance K and substance P as possible endogenous substrates of angiotensin converting enzyme in the brain.

In the brain angiotensin converting enzyme is highly localized to a striatonigral pathway, which contains no endogenous angiotensin. Substance P, also localized to a striatonigral pathway, is degraded by ACE via two different pathways. The lung and striatal isozymes of angiotensin converting enzyme exhibit differential cleavage of substance P, with lung preferring an initial tripeptide cleavage, and striatum an initial dipeptide cleavage. Substance K is degraded by the striatal isozyme but is not cleaved by the lung isozyme. Substance P 5-11 is not cleaved by either form of angiotensin converting enzyme.

Amino Acid Sequence↗

Angiotensin-converting enzyme in the testis and epididymis: differential development and pituitary regulation of isozymes.

Angiotensin-converting enzyme (ACE, EC 3.14.5.1) is found in particulate fractions of the epididymis but not in soluble epididymal fractions or in the testis of 4-week-old rats. [3H]Captopril autoradiography of testis and epididymis from 4-week-old rats confirms the association of ACE with epididymal ducts but not the testis. ACE appears in the testis between 4 and 6 weeks of age. Soluble ACE is not detectable in the epididymis until 6-7 weeks of age. Within the epididymis, regions closest to the testis develop soluble ACE activity about 1 week before those nearest to the vas deferens. Hypophysectomy of 10 week-old-rats depletes greater than 95% of ACE activity from the testis and soluble fractions of the epididymis, with little change in ACE levels from particulate fractions of the epididymis. [3H]Captopril autoradiography after hypophysectomy reveals luminal and epithelial ACE in the epididymis. The presence of particulate ACE in the epididymis under conditions where there is no testicular ACE indicates that the two forms are synthesized separately. However, soluble ACE from the epididymis might be derived from the membrane-associated ACE of the testis. Such a relationship is supported by the lag of 1 week between the development of ACE in the initial segment of the epididymis and the tail of the epididymis, and by the occurrence of soluble epididymis ACE only in those animals with testicular ACE activity.

Animals↗