Biomedical subjects

A Rosenthal

Publications and source records attributed to A Rosenthal.

At least 19 recordsLinked to original sources

PubMed1996

The tumour-suppressor gene patched encodes a candidate receptor for Sonic hedgehog.

The protein Sonic hedgehog (Shh) controls patterning and growth during vertebrate development. Here we demonstrate that it binds Patched (vPtc), which has been identified as a tumour-suppressor protein in basal cell carcinoma, with high affinity. We show that Ptc can form a physical complex with a newly cloned vertebrate homologue of the Drosophila protein Smoothened (vSmo), and that vSmo is coexpressed with vPtc in many tissues but does not bind Shh directly. These findings, combined with available genetic evidence from Drosophila, support the hypothesis that Ptc is a receptor for Shh, and that vSmo could be a signalling component that is linked to Ptc.

Amino Acid Sequence↗

PubMed1996

The genomic organization of a human creatine transporter (CRTR) gene located in Xq28.

During the course of a large-scale sequencing project in Xq28, a human creatine transporter (CRTR) gene was discovered. The gene is located approximately 36 kb centromeric to ALD. The gene contains 13 exons and spans about 8.5 kb of genomic DNA. Since the creatine transporter has a prominent function in muscular physiology, it is a candidate gene for Barth syndrome and infantile cardiomyopathy mapped to Xq28.

Base Sequence↗

PubMed1996

Selection for genes encoding secreted proteins and receptors.

Extracellular proteins play an essential role in the formation, differentiation, and maintenance of multicellular organisms. Despite that, the systematic identification of genes encoding these proteins has not been possible. We describe here a highly efficient method to isolate genes encoding secreted and membrane-bound proteins by using a single-step selection in yeast. Application of this method, termed signal peptide selection, to various tissues yielded 559 clones that appear to encode known or novel extracellular proteins. These include members of the transforming growth factor and epidermal growth factor protein families, endocrine hormones, tyrosine kinase receptors, serine/threonine kinase receptors, seven transmembrane receptors, cell adhesion molecules, extracellular matrix proteins, plasma proteins, and ion channels. The eventual identification of most, or all, extracellular signaling molecules will advance our understanding of fundamental biological processes and our ability to intervene in disease states.

Amino Acid Sequence↗

PubMed1996

Renal and neuronal abnormalities in mice lacking GDNF.

Glial cell-line derived neurotrophic factor (GDNF) is a potent survival factor for embryonic midbrain dopaminergic, spinal motor, cranial sensory, sympathetic, and hindbrain noradrenergic neurons, and is available to these cells in vivo. It is therefore considered a physiological trophic factor and a potential therapeutic agent for Parkinson's disease, amyotrophic lateral sclerosis, and Alzheimer's disease. Here we show that at postnatal day 0 (P0), GDNF-deficient mice have deficits in dorsal root ganglion, sympathetic and nodose neurons, but not in hindbrain noradrenergic or midbrain dopaminergic neurons. These mice completely lack the enteric nervous system (ENS), ureters and kidneys. Thus GDNF is important for the development and/or survival of enteric, sympathetic and sensory neurons and the renal system, but is not essential for catecholaminergic neurons in the central nervous system (CNS).

Animals↗

PubMed1996

Characterization of a multicomponent receptor for GDNF.

Glial-cell-line-derived neurotrophic factor (GDNF) is a potent survival factor for central and peripheral neurons, and is essential for the development of kidneys and the enteric nervous system. Despite the potential clinical and physiological importance of GDNF, its mechanism of action is unknown. Here we show that physiological responses to GDNF require the presence of a novel glycosyl-phosphatidylinositol (GPI)-linked protein (designated GDNFR-alpha) that is expressed on GDNF-responsive cells and binds GDNF with a high affinity. We further demonstrate that GDNF promotes the formation of a physical complex between GDNFR-alpha and the orphan tyrosin kinase receptor Ret, thereby inducing its tyrosine phosphorylation. These findings support the hypothesis that GDNF uses a multi-subunit receptor system in which GDNFR-alpha and Ret function as the ligand-binding and signalling components, respectively.

Amino Acid Sequence↗

PubMed1996

Genomic Organization of the ATM gene.

The ATM gene was recently identified and found to be responsible for the genetic disorder ataxiatelgiectasia. The major ATM transcript is 13 kb. Using long-distance PCR, we determined the genomic structure of this gene and identified all of its exon-intron boundaries. The ATM gene spans approximately 150 kb of genomic DNA and consists of 66 exons. The initiation codon falls within exon 4. The last exon is 3.8 kb and contains the stop codon and a 3'-untranslated region of about 3600 nucleotides.

Ataxia Telangiectasia↗

PubMed1996

Transforming growth factor-beta 3, glial cell line-derived neurotrophic factor, and fibroblast growth factor-2, act in different manners to promote motoneuron survival in vitro.

Developing chick motoneurons depend on as yet unidentified factors from the periphery and the central nervous system for their survival. Using cultures of purified embryonic motoneurons, we show that basic fibroblast growth factor (FGF-2) or transforming growth factor-beta 3 (TGF beta 3) each have only low survival-promoting activity when tested alone, but act synergistically to keep motoneurons alive for at least 3 days. Glial cell line-derived neurotrophic factor (GDNF), another member of the TGF beta family, was itself sufficient to maintain a population of motoneurons. However, its effect was not significantly increased by the addition of FGF-2. These results suggest that FGF-2, TGF beta 3, and GDNF, which are all present in the environment of developing motoneurons, may act different mechanisms as physiological survival factors for this population of central neurons.

Animals↗

PubMed1996

Cardiotrophin-1, a cytokine present in embryonic muscle, supports long-term survival of spinal motoneurons.

The muscle-derived factors required for survival of embryonic motoneurons are not clearly identified. Cardiotrophin-1 (CT-1), a cytokine related to ciliary neurotrophic factor (CNTF), is expressed at high levels in embryonic limb bud and is secreted by differentiated myotubes. In vitro, CT-1 kept 43% of purified E14 rat motoneurons alive for 2 weeks (EC50 = 20 pM). In vivo, CT-1 protected neonatal sciatic motoneurons against the effects of axotomy. CT-1 action on motoneurons was inhibited by phosphatidylinositol-specific phospholipase C (PIPLC), suggesting that CT-1 may act through a GPI-linked component. Since no binding of CT-1 to CNTFR alpha was detected, CT-1 may use a novel cytokine receptor alpha subunit. CT-1 may be important in normal motoneuron development and as a potential tool for slowing motoneuron degeneration in human diseases.

Animals↗

PubMed1996

Identification of a gene disrupted by a microdeletion in a patient with X-linked retinitis pigmentosa (XLRP).

The gene for the most frequent from of X-linked retinitis pigmentosa (XLRP), RP3, has been assigned by genetic and physical mapping to a segment of less than 1000 kbp, which is flanked by the marker DXS1110 and the ornithine transcarbamylase (OTC) gene. In search of microdeletions, we have screened the DNA of 30 unrelated patients with XLRP by employing a representative set of YAC-derived DNA fragments that were generated by restriction enzyme digestion and PCR amplification. In one of these patients, a 6.4 kbp microdeletion was detected which was not present in the DNA of 444 male controls. A cosmid contig spanning the deletion was constructed and used to isolate cDNAs from retina-specific libraries. Exons corresponding to these expressed sequences as well as other putative exons were identified by sequencing more than 30 kbp of the critical region. So far, no point mutations in these putative exon sequences have been identified.

Cell Line↗

PubMed1996

Anatomic, histologic, and magnetic resonance imaging abnormalities of the shoulder.

Six fresh frozen, human cadaver shoulders were evaluated for gross anatomic, magnetic resonance imaging, and histologic abnormalities. The shoulders underwent routine magnetic resonance imaging with and without intraarticular Gadolinium using a standard surface shoulder coil. The shoulders were dissected in a systematic fashion to yield 18 anatomic specimens from the supraspinatus and infraspinatus tendon as well as the glenoid labrum. These specimens were studied histologically using hematoxylin and eosin and Goldner's trichrome stains. Gross anatomic and magnetic resonance image abnormalities of the rotator cuff corresponded to histologic changes consistent with tendon degeneration. However, there was a poor correlation between gross anatomic, magnetic resonance image, and histologic changes of degeneration in the glenoid labrum. In general, histologic degeneration was more severe than abnormalities seen either grossly or on magnetic resonance images.

Adult↗

PubMed1996

Sequencing the 500-kb GC-rich symbiotic replicon of Rhizobium sp. NGR234 using dye terminators and a thermostable "sequenase": a beginning.

Genomes of the soil-borne nitrogen-fixing symbionts of legumes [Azo(Brady)Rhizobium species] typically have GC contents of 59-65 mol%. As a consequence, compressions (up to 400 per cosmid) are common using automated dye primer shotgun sequencing methods. To overcome this difficulty, we have exclusively applied dye terminators in combination with a thermostable "sequenase" for shotgun sequencing GC-rich cosmids from pNGR234a, the 500-kbp symbiotic replicon of Rhizobium sp. NGR234. A thermostable sequenase incorporates dye terminators into DNA more efficiently than Taq DNA polymerase, thus reducing the concentrations needed (20- to 250-fold). Unincorporated dye terminators can simply be removed by ethanol precipitation. Here, we present data of pXB296, one of 23 overlapping cosmids representing pNGR234a. We demonstrate that the greatly reduced number of compressions results in a much faster assembly of cosmid sequence data by comparing assembly of the shotgun data from pXB296 and the data from another pNGR234a cosmid (pXB110) sequenced using dye primer methods. Within the 34,010-bp sequence from pXB296, 28 coding regions were predicted. All of them showed significant homologies to known proteins, including oligopeptide permeases, an essential cluster for nitrogen fixation, and the C4-dicarboxylate transporter DctA.

Base Composition↗

PubMed1995

Neurotrophin-4/5 postpones the death of injured spinal motoneurons in newborn rats.

We have compared the short- and long-term effects of Neurotrophin-4/5 (NT-4/5) on the survival of spinal motoneurons in neonatal rats. To this aim, the sciatic nerve was cut in newborn rats and NT-4/5 or buffer were applied to the proximal nerve stem in a gelfoam as well as by daily local injection. The number of motoneurons or ventral root fibers was determined 4, 11, and 14 days later. Four days after received NT-4/5 lost only 19% + 2.7% (540 + 81). No systemic effect on the contralateral motoneurons was observed. Surprisingly, 11 and 14 days following the operation, the loss of motoneurons and of ventral root fibers was the same in buffer and NT-4/5 treated animal despite the daily treatment. Thus, although NT-4/5 is a potent survival factor for motoneurons in culture and can transiently prevent the death of motoneurons in vivo, it can not, under these experimental conditions, permanently rescue lesioned motoneurons. These results indicate that other trophic factors or combinations of factors may be required to permanently prevent the death of spinal motoneurons and that the short term survival promoting effects of neurotropic factors in motoneuron lesion models can not be used to predict their therapeutic potential in chronic neurodegenerative disorders.

Animals↗

PubMed1995

Cardiotrophin-1. Biological activities and binding to the leukemia inhibitory factor receptor/gp130 signaling complex.

Cardiotrophin-1 (CT-1) is a newly isolated cytokine that was identified based on its ability to induce cardiac myocyte hypertrophy. It is a member of the family of cytokines that includes interleukins-6 and -11, leukemia inhibitory factor (LIF), ciliary neurotrophic factor, and oncostatin M. These cytokines induce a pleiotropic set of growth and differentiation activities via receptors that use a common signaling subunit, gp130. In this work we determine the activity of CT-1 in six in vitro biological assays and examine the composition of its cell surface receptor. We find that CT-1 is inactive in stimulating the growth of the hybridoma cell line, B9 and inhibits the growth of the mouse myeloid leukemia cell line, M1. CT-1 induces a phenotypic switch in rat sympathetic neurons and promotes the survival of rat dopaminergic and chick ciliary neurons. CT-1 also inhibits the differentiation of mouse embryonic stem cells. CT-1 and LIF cross-compete for binding to M1 cells, Kd [CT-1] approximately 0.7 nM, and this binding is inhibited by an anti-gp130 monoclonal antibody. Both ligands can be specifically cross-linked to a protein on M1 cells with the mobility of the LIF receptor (approximately 200 kDa). In addition, CT-1 binds directly to a purified, soluble form of the LIF receptor in solution (Kd approximately 2 nM). These data show that CT-1 has a wide range of hematopoietic, neuronal, and developmental activities and that it can act via the LIF receptor and the gp130 signaling subunit.

Amino Acid Sequence↗

PubMed1995

Mesencephalic dopaminergic neurons protected by GDNF from axotomy-induced degeneration in the adult brain.

Glial-cell-line-derived neurotrophic factor (GDNF) promotes survival of embryonic dopaminergic neurons in culture, and its expression pattern suggests a role as a transient target-derived trophic factor for dopaminergic neurons of the substantia nigra. These neurons participate in the control of motor activity, emotional status and cognition, and they degenerate in Parkinson's disease for unknown reasons. To test whether GDNF has a trophic effect on dopaminergic neurons in the adult brain, we used a rat model in which these neurons are induced to degenerate by transecting their axons within the medial forebrain bundle. We report here that axotomy resulted in loss of half the tyrosine hydroxylase-expressing neurons in the substantia nigra. This loss was largely prevented by repeated injections of GDNF adjacent to the substantia nigra. Our findings suggest that GDNF or related molecules may be useful for the treatment of Parkinson's disease.

Animals↗

PubMed1995

Control of neuronal diversity by the floor plate: contact-mediated induction of midbrain dopaminergic neurons.

The notochord and floor plate contribute to patterning the ventral neural tube in part by expressing a diffusible factor that induces motoneurons. To determine the mechanisms that direct the development of other classes of ventral neurons, we studied the development of dopaminergic neurons that reside near motoneurons in the ventral midbrain. We provide evidence that dopaminergic neurons develop in the vicinity of the floor plate and that they can be specified by the floor plate in vitro and in vivo. Unlike motoneurons, efficient induction of dopaminergic neurons requires contact with floor plate cells. These results suggest that neuronal diversification along the dorsal-ventral axis may be achieved partly through the concerted action of diffusible and contact-dependent signals from a single organizing center, the floor plate.

Animals↗

PubMed1995

Malnutrition in hospitalized children with congenital heart disease.

OBJECTIVE: To determine the prevalence of malnutrition among hospitalized children with congenital heart disease by age, disease process, and clinical status. DESIGN: Cross-sectional, retrospective chart review. SETTING: Pediatric cardiology units at a 150-bed tertiary care teaching hospital in Ann Arbor, Mich. PATIENTS: Patients (n = 160) were randomly selected from consecutive admissions to the Pediatric Cardiology and Thoracic Surgery Services during a 1-year period. INTERVENTION: None. MAIN OUTCOME MEASURES: Acute and chronic malnutrition, assessed by comparing the patients' weight and height with established means. RESULTS: Acute and chronic malnutrition occurred in 33% and 64% of the patients, respectively. Age, diagnostic category, and symptoms were associated with malnutrition. Eighty percent of infants presented with acute malnutrition compared with 18% of patients of other ages (P < .001). Malnutrition affected 60% of patients with left-to-right shunts, 53% of patients with complex heart disease, and no patients with primary rhythm disturbances. Acute malnutrition affected 11% and chronic malnutrition affected 50% of patients with left-sided heart obstruction. Acute or chronic malnutrition occurred in 70% or more of patients with cyanosis and/or congestive heart failure but in only 30% of patients with neither (P < .001). CONCLUSION: Malnutrition in hospitalized children with congenital heart disease remains common, highlighting the importance of nutritional screening and intervention.

Acute Disease↗

PubMed1995

Formulation and characterization of dry mixes based on dehydrated fresh high-lysine corn.

Fresh sweet corn pulp from high-lysine corn was dehydrated in a drum-dryer and utilized in the formulation of creamy instant soups. Studied formulas contained 27.5 to 67% dehydrated high-lysine corn pulp. The sensory profiles of the formulas improved with increasing proportion of dehydrated fresh corn pulp. Formula with 27.5% fresh corn pulp was rated lowest by the tasters on the basis of poor appearance, low characteristic fresh corn flavor and low overall impression. Formulas with 60 and 67% corn pulp rated highest in sensory quality and were nutritionally adequate. The PER for these formulas did not differ from casein control diet but nitrogen absorption and nitrogen retention was inferior for the formulas protein as compared to casein.

Animals↗

PubMed1995

Exon 2 of the gene for neural cell adhesion molecule L1 is alternatively spliced in B cells.

L1CAM is a neural cell adhesion molecule expressed mainly on neurones' cell surface and plays an important role in the developing fetal brain. Recently, we have shown that mutations in the gene encoding L1CAM are responsible for three related neurological disorders including the most common form of inherited hydrocephalus. During our genetic analysis, we have discovered that L1CAM is also expressed on the surface of B cells but that the messenger RNA in this tissue is different to that in brain through alternative splicing of the L1 gene. This indicates that this region of the L1 molecule has a distinct role in brain cells compared to B lymphocytes and confirms its importance in brain development.

Alternative Splicing↗