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Biomedical subjects

A Rosenthal

Publications and source records attributed to A Rosenthal.

At least 73 records · Page 4Linked to original sources
PubMed2000

Differential gene expression by endothelial cells in distinct angiogenic states.

Angiogenesis is a complex process that can be regarded as a series of sequential events comprising a variety of tissue cells. The major problem when studying angiogenesis in vitro is the lack of a model system mimicking the various aspects of the process in vivo. In this study we have used two in vitro models, each representing different and distinct aspects of angiogenesis. Differentially expressed genes in the two culture forms were identified using the suppression subtractive hybridization technique to prepare subtracted cDNA libraries. This was followed by a differential hybridization screen to pick up overexpressed clones. Using comparative multiplex RT-PCR we confirmed the differential expression and showed differences up to 14-fold. We identified a broad range of genes already known to play an important role during angiogenesis like Flt1 or TIE2. Furthermore several known genes are put into the context of endothelial cell differentiation, which up to now have not been described as being relevant to angiogenesis, like NrCAM, Claudin14, BMP-6, PEA-15 and PINCH. With ADAMTS4 and hADAMTS1/METH-1 we further extended the set of matrix metalloproteases expressed and regulated by endothelial cells.

Base Sequence↗
PubMed2000

Propofol versus midazolam for conscious sedation guided by processed EEG during endoscopic retrograde cholangiopancreatography: a prospective, randomized, double-blind study.

BACKGROUND AND STUDY AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is a complex procedure, which requires appropriate sedation. The aim of this prospective, randomized, double-blind study was to compare the quality and characteristics of sedation with midazolam or propofol in patients undergoing ERCP. PATIENTS AND METHODS: A total of 32 patients undergoing ERCP were randomly allocated for sedation with propofol (n = 15) or midazolam (n = 17). Blood pressure, heart rate, and O2 saturation were monitored. Sedation was maintained at near constant levels by use of the spectral edge frequency (SEF) technique, an EEG-based method for measuring the depth of sedation. Clinical variables, patient cooperation, time to recovery, and amnesia served as outcome variables. RESULTS: There was no significant difference between the two study groups in patient characteristics. The "target SEF" was 13.6 +/- 0.7 Hz for the propofol group and 14.8 +/- 1.1 Hz for the midazolam group (n.s.). The only clinical parameter with a significant difference between the groups was the percent of time in which the heart rate deviated more than 20% from baseline for at least 2 minutes, i.e. 14.6 +/- 2.0 % for propofol and 48.2 +/- 38.0% for midazolam (P<0.01). Patient cooperation was better in the propofol group than in the midazolam group (full cooperation, 13/15 vs. 1/17, respectively; P<0.001). Patient recovery was significantly quicker in the propofol group (P<0.001). The degree of amnesia was similar in both groups; no patient in either group remembered details of the procedure. CONCLUSIONS: ERCP is better tolerated by patients sedated with propofol compared with midazolam, with a shorter recovery time and lesser hemodynamic side effects. Propofol should be considered to be the sedative drug of choice for ERCP.

Adolescent↗
PubMed2000

Comparative genome sequence analysis of the Bpa/Str region in mouse and Man.

The progress of human and mouse genome sequencing programs presages the possibility of systematic cross-species comparison of the two genomes as a powerful tool for gene and regulatory element identification. As the opportunities to perform comparative sequence analysis emerge, it is important to develop parameters for such analyses and to examine the outcomes of cross-species comparison. Our analysis used gene prediction and a database search of 430 kb of genomic sequence covering the Bpa/Str region of the mouse X chromosome, and 745 kb of genomic sequence from the homologous human X chromosome region. We identified 11 genes in mouse and 13 genes and two pseudogenes in human. In addition, we compared the mouse and human sequences using pairwise alignment and searches for evolutionary conserved regions (ECRs) exceeding a defined threshold of sequence identity. This approach aided the identification of at least four further putative conserved genes in the region. Comparative sequencing revealed that this region is a mosaic in evolutionary terms, with considerably more rearrangement between the two species than realized previously from comparative mapping studies. Surprisingly, this region showed an extremely high LINE and low SINE content, low G+C content, and yet a relatively high gene density, in contrast to the low gene density usually associated with such regions.

3-Hydroxysteroid Dehydrogenases↗
PubMed2000

Molecular cloning of Xp11 breakpoints in two unrelated mentally retarded females with X;autosome translocations.

Mental retardation is a very common and extremely heterogeneous disorder that affects about 3% of the human population. Its molecular basis is largely unknown, but many loci have been mapped to the X chromosome. We report on two mentally retarded females with X;autosome translocations and breakpoints in Xp11, viz., t(X;17)(p11;p13) and t(X;20)(p11;q13). (Fiber-) FISH analysis assigned the breakpoints to different subbands, Xp11.4 and Xp11.23, separated by approximately 8 Mb. High-resolution mapping of the X- chromosome breakpoints using Southern blot hybridization resulted in the isolation of breakpoint-spanning genomic subclones of 3 kb and 0. 5 kb. The Xp11.4 breakpoint is contained within a single copy sequence, whereas the Xp11.23 breakpoint sequence resembles an L1 repetitive element. Several expressed sequences map close to the breakpoints, but none was found to be inactivated. Therefore, mechanisms other than disruption of X-chromosome genes likely cause the phenotypes.

Adolescent↗
PubMed2000

Elevated DNA sequence diversity in the genomic region of the phosphatase PPP2R3L gene in the human pseudoautosomal region.

The evolution, inheritance and recombination rate of genes located in the pseudoautosomal region 1 (PAR1) is exceptional within the human genome. Pseudoautosomal genes are identical on X and Y chromosomes and are not inherited in a sex linked manner. Due to an obligatory recombination event in male meiosis, pseudoautosomal genes are exchanged frequently between X and Y chromosomes. During the isolation, characterization and sequencing of a novel gene PPP2R3L, which was classified by sequence homology as a novel member of the protein phosphatase regulatory subunit families, it became apparent that cosmids of different origin harboring this gene are highly polymorphic between individuals, both at the nucleotide level and in the number.

Amino Acid Sequence↗
PubMed1999

Hedgehog signal transduction: from flies to vertebrates.

The patterning and morphogenesis of multicellular organisms require a complex interplay of inductive signals which control proliferation, growth arrest, and differentiation of different cell types. A number of such signaling molecules have been identified in vertebrates and invertebrates. The molecular dissection of these pathways demonstrated that in vertebrates, mutations or abnormals function of these signaling pathways were often associated with developmental disorders and cancer formation. The Hedgehog (Hh) family of secreted proteins provides a perfect example of such signaling proteins. In the following review, we will not discuss in detail the role of Hh as a morphogen, but rather focus on its signal transduction pathway and its role in various human disorders.

Chromosome Aberrations↗
PubMed1999

Exhaustive mining of EST libraries for genes differentially expressed in normal and tumour tissues.

A four-step procedure for the efficient and systematic mining of whole EST libraries for differentially expressed genes is presented. After eliminating redundant entries from the EST library under investigation (step 1), contigs of maximal length are built upon each remaining EST using about 4 000 000 public and proprietary ESTs (step 2). These putative genes are compared against a database comprising ESTs from 16 different tissues (both normal and tumour affected) to determine whether or not they are differentially expressed (step 3; electronic northern). Fisher's exact test is used to assess the significance of differential expression. In step 4, an attempt is made to characterise the contigs obtained in the assembly through database comparison. A case study of the CGAP library NCI_CGAP_Br1.1, a library made from three (well, moderately, and poorly differentiated) invasive ductal breast tumours (2126 ESTs in total) was carried out. Of the maximal contigs, 139 were found to be significantly (alpha = 0.05) over-expressed in breast tumour tissue, while 13 appeared to be down-regulated.

Animals↗
PubMed1999

Sequence analysis of the ATM gene in 20 patients with RTOG grade 3 or 4 acute and/or late tissue radiation side effects.

PURPOSE: Patients with ataxia-telangiectasia (A-T) show greatly increased radiation sensitivity and cancer predisposition. Family studies imply that the otherwise clinically silent heterozygotes of this autosomal recessive disease run a 3.5 to 3.8 higher risk of developing cancer. In vitro studies suggest moderately increased cellular radiation sensitivity of A-T carriers. They may also show elevated clinical radiosensitivity. We retrospectively examined patients who presented with severe adverse reactions during or after standard radiation treatment for mutations in the gene responsible for A-T, ATM, considering a potential means of future identification of radiosensitive individuals prospectively to adjust dosage schedules. MATERIAL AND METHODS: We selected 20 cancer patients (breast, 11; rectum, 2; ENT, 2; bladder, 1; prostate, 1; anus, 1; astrocytoma, 1; Hodgkins lymphoma, 1) with Grade 3 to 4 (RTOG) acute and/or late tissue radiation side effects by reaction severity. DNA from the peripheral blood of patients was isolated. All 66 exons and adjacent intron regions of the ATM gene were PCR-amplified and examined for mutations by a combination of agarose gel electrophoresis, single-stranded conformational polymorphism (SSCP) analysis, and exon-scanning direct sequencing. RESULTS: Only 2 of the patients revealed altogether four heteroallelic sequence variants. The latter included two single-base deletions in different introns, a single-base change causing an amino acid substitution in an exon, and a large insertion in another intron. Both the single-base deletions and the single-base change represent known polymorphisms. The large insertion was an Alu repeat, shown not to give rise to altered gene product. CONCLUSIONS: Despite high technical efforts, no unequivocal ATM mutation was detected. Nevertheless, extension of similar studies to larger and differently composed cohorts of patients suffering severe adverse effects of radiotherapy, and application of new technologies for mutation detection may be worthwhile to assess the definite prevalence of significant ATM mutations within the group of radiotherapy patients with adverse reactions. To date, it must be recognized that our present results do not suggest that heterozygous ATM mutations are involved in clinically observed radiosensitivity but, rather, invoke different genetic predisposition or so far unknown exogenous factors.

Adult↗
PubMed1999

Mutations in the zebrafish unmask shared regulatory pathways controlling the development of catecholaminergic neurons.

The mechanism by which pluripotent progenitors give rise to distinct classes of mature neurons in vertebrates is not well understood. To address this issue we undertook a genetic screen for mutations which affect the commitment and differentiation of catecholaminergic (CA) [dopaminergic (DA), noradrenergic (NA), and adrenergic] neurons in the zebrafish, Danio rerio. The identified mutations constitute five complementation groups. motionless and foggy affect the number and differentiation state of hypothalamic DA, telencephalic DA, retinal DA, locus coeruleus (LC) NA, and sympathetic NA neurons. The too few mutation leads to a specific reduction in the number of hypothalamic DA neurons. no soul lacks arch-associated NA cells and has defects in pharyngeal arches, and soulless lacks both arch-associated and LC cell groups. Our analyses suggest that the genes defined by these mutations regulate different steps in the differentiation of multipotent CA progenitors. They further reveal an underlying universal mechanism for the control of CA cell fates, which involve combinatorial usage of regulatory genes.

Animals↗
PubMed1999

Sonic hedgehog signaling by the patched-smoothened receptor complex.

BACKGROUND: The Hedgehog (Hh) family of secreted proteins is involved in a number of developmental processes as well as in cancer. Genetic and biochemical data suggest that the Sonic hedgehog (Shh) receptor is composed of at least two proteins: the tumor suppressor protein Patched (Ptc) and the seven-transmembrane protein Smoothened (Smo). RESULTS: Using a biochemical assay for activation of the transcription factor Gli, a downstream component of the Hh pathway, we show here that Smo functions as the signaling component of the Shh receptor, and that this activity can be blocked by Ptc. The inhibition of Smo by Ptc can be relieved by the addition of Shh. Furthermore, oncogenic forms of Smo are insensitive to Ptc repression in this assay. Mapping of the Smo domains required for binding to Ptc and for signaling revealed that the Smo-Ptc interaction involves mainly the amino terminus of Smo, and that the third intracellular loop and the seventh transmembrane domain are required for signaling. CONCLUSIONS: These data demonstrate that Smo is the signaling component of a multicomponent Hh receptor complex and that Ptc is a ligand-regulated inhibitor of Smo. Different domains of Smo are involved in Ptc binding and activation of a Gli reporter construct. The latter requires the third intracellular loop and the seventh transmembrane domain of Smo, regions often involved in coupling to G proteins. No changes in the levels of cyclic AMP or calcium associated with such pathways could be detected following receptor activation, however.

Amino Acid Sequence↗
PubMed1999

Non-LTR retrotransposons with unique integration preferences downstream of Dictyostelium discoideum tRNA genes.

Retrotransposable elements are genetic enti ties which move and replicate within host cell genomes We have previously reported on the structures and ge nomic distributions of two non-long terminal repea (non-LTR) retrotransposons, DRE and Tdd-3, in the eukaryotic microorganism Dictyostelium discoideum DRE elements are found inserted upstream, and Tdd-3 elements downstream, of transfer RNA (tRNA) genes with remarkable position and orientation specificities The data set currently available from the Dictyostelium Genome Project led to the characterisation of two repetitive DNA elements which are related to the D. discoideum non-LTR retrotransposon Tdd-3 in both their structural properties and genomic distributions. It appears from our data that in the D. discoideum genome tRNA genes are major targets for the insertion of mobilised non-LTR retrotransposons. This may be interpreted as the consequence of a process of coevolution, allowing a viable population of retroelements to transpose without being deleterious to the small microbial host genome which carries only short intergenic DNA sequences. A new nomenclature is introduced to designate all tRNA gene-targeted non-LTR retrotransposons (TREs) in the D. discoideum genome. TREs inserted 5' and 3' of tRNA genes are named TRE5 and TRE3, respectively. According to this nomenclature DRE and Tdd-3 are renamed TRE5-A and TRE3-A, respectively. The new retroelements described in this study are named TRE3-B (formerly RED) and TRE3-C.

Amino Acid Sequence↗
PubMed1999

Ketorolac tromethamine 0.5% ophthalmic solution in the treatment of moderate to severe ocular inflammation after cataract surgery: a randomized, vehicle-controlled clinical trial.

PURPOSE: To investigate the efficacy and safety of ketorolac tromethamine 0.5% ophthalmic solution (Acular; Allergan, Inc, Irvine, California) in the treatment of moderate to severe anterior segment inflammation developing after unilateral cataract surgery with intraocular lens implantation. METHODS: Only patients who exhibited moderate or greater levels of cells and flare 1 day after surgery were included in this multicenter, double-masked, randomly assigned, parallel-group study. Topical ketorolac or vehicle solution (Allergan, Inc) was administered to the treated eye four times daily, starting the day after surgery and continuing for 14 days. RESULTS: Ketorolac was significantly more effective than the vehicle solution in reducing anterior chamber cells (P < or = .030) and flare (P < or = .025), conjunctival erythema (P < or = .046), ciliary flush (P < or = .006), tearing (P < or = .012), photophobia (P < or = .014), and pain (P < or = .049). Half as many patients from the ketorolac group (14/51) were discontinued from the study for lack of efficacy, compared with the vehicle group (28/51; P = .005). There was no significant difference between ketorolac and the vehicle solution in changes in visual acuity, intraocular pressure, biomicroscopic or ophthalmoscopic variables, or adverse events. CONCLUSIONS: Ketorolac tromethamine 0.5% ophthalmic solution is safe and provides substantial anti-inflammatory activity in the treatment of moderate to severe anterior segment inflammation developing after cataract surgery and intraocular lens implantation.

Adult↗
PubMed1999

Efficacy and safety profile of ketorolac 0.5% ophthalmic solution in the prevention of surgically induced miosis during cataract surgery.

This multicenter, double-masked, randomized, parallel study compared the efficacy and safety profile of ketorolac tromethamine 0.5% ophthalmic solution with that of its vehicle in the maintenance of pupillary mydriasis during cataract surgery. A total of 176 adult patients scheduled to undergo unilateral extracapsular cataract extraction and posterior-chamber intraocular lens implantation received either ketorolac tromethamine 0.5% (n = 89) or vehicle (n = 87), starting 2 hours before surgery. One drop of study medication was instilled every 30 minutes for a total of 4 drops. No epinephrine was used in the intraoperative irrigating solution. Pupil diameter was measured with a caliper at 3 time points during surgery. To ensure participant safety, biomicroscopy, ophthalmoscopy, intraocular pressure, adverse events, and preoperative and postoperative visual acuity and refractive error were also monitored. The mean change in horizontal and vertical pupil diameter from the time of the first incision to after cortical irrigation and aspiration was significantly less with active ketorolac than with vehicle (P < or = 0.014). Consequently, mean pupil diameter after cortical irrigation and aspiration was significantly greater with ketorolac than with vehicle (P < or = 0.030). No significant between-group differences were observed in the change in pupil diameter between the end of surgery and postoperative administration of a miotic agent, safety variables, or occurrence of adverse events. In this study, ketorolac tromethamine 0.5% ophthalmic solution provided effective and well-tolerated inhibition of surgically induced miosis during cataract surgery.

Aged↗
PubMed1999

Efficacy and safety of nonpreserved ketorolac ophthalmic solution in postoperative ocular pain following radial keratotomy.

PURPOSE: To investigate the efficacy and safety of nonpreserved ketorolac tromethamine 0.5% ophthalmic solution in relieving pain following radial keratotomy (RK). SETTING: Multicenter clinical trial. METHODS: Topical ketorolac was compared with its vehicle in a double-masked, randomized, parallel-group study involving 170 RK patients. Patients were treated with nonpreserved ketorolac 0.5% ophthalmic solution or the vehicle 4 times daily beginning immediately after surgery and continuing for 3 days or until they no longer had ocular pain. RESULTS: At several intervals, patients treated with ketorolac reported significantly greater pain relief and less pain intensity than patients treated with the vehicle. The time required for patients to first report "complete relief" or "no pain" was shorter in the ketorolac than in the vehicle group (P < or = .006). Patients in the ketorolac group used less escape medication (acetaminophen) (P < or = .001) and had fewer sleep difficulties (P < or = .031), fewer symptoms of ocular discomfort (P < or = .028), and less difficulty performing activities of daily living (P = .048). Patients treated with ketorolac experienced the same low rate of treatment-related adverse events as those treated with the vehicle and exhibited the same improvement in visual acuity and manifest refraction. CONCLUSIONS: Nonpreserved ketorolac tromethamine 0.5% ophthalmic solution was significantly more effective than, and as safe as, the vehicle in alleviating the postoperative pain associated with RK. This resulted in significant improvements in patient quality of life and less need for oral analgesics, suggesting that topical ketorolac is an appropriate treatment option for ocular pain following RK.

Adolescent↗
PubMed1999

Development of noradrenergic neurons in the zebrafish hindbrain requires BMP, FGF8, and the homeodomain protein soulless/Phox2a.

We report that the zebrafish mutation soulless, in which the development of locus coeruleus (LC) noradrenergic (NA) neurons failed to occur, disrupts the homeodomain protein Phox2a. Phox2a is not only necessary but also sufficient to induce Phox2b+ dopamine-beta-hydroxylase+ and tyrosine hydroxylase+ NA neurons in ectopic locations. Phox2a is first detected in LC progenitors in the dorsal anterior hindbrain, and its expression there is dependent on FGF8 from the mid/hindbrain boundary and on optimal concentrations of BMP signal from the epidermal ectoderm/future dorsal neural plate junction. These findings suggest that Phox2a coordinates the specification of LC in part through the induction of Phox2b and in response to cooperating signals that operate along the mediolateral and anteroposterior axes of the neural plate.

Amino Acid Sequence↗