Detection and characterization of a 3' untranslated region ribonucleoprotein complex associated with human alpha-globin mRNA stability.

The highly stable nature of globin mRNA is of central importance to erythroid cell differentiation. We have previously identified cytidine-rich (C-rich) segments in the human alpha-globin mRNA 3' untranslated region (alpha-3'UTR) which are critical in the maintenance of mRNA stability in transfected erythroid cells. In the present studies, we have detected trans-acting factors which interact with these cis elements to mediate this stabilizing function.

[Simulation of myocardial action potentials of various cell types in relation to neural parameters].

Action potentials of various myocardial cell types were simulated in a computer model based on current knowledge of the electrical properties of ionic channels and pumps in the ventricular cell membrane and the sarcoplasmic reticulum. The transport mechanisms of sodium, potassium, calcium and chlorine ions through the cell membrane are described mathematically, as is the exchange of calcium between the myoplasm and sarcoplasmic reticulum. Ten ionic channels and three pumps of the cell membrane are taken into account, while three channels and one pump of the sarcoplasmic reticulum are considered in the computations.

Erythroid cell-specific determinants of alpha-globin mRNA stability.

Although globin mRNAs are considered prototypes of highly stable messages, the mechanisms responsible for their longevity remain largely undefined. As an initial step in identifying potential cis-acting elements or structures which contribute to their stability, we analyzed the defect in expression of a naturally occurring alpha 2-globin mutant, alpha Constant Spring (CS). The CS mutation is a single-base change in the translation termination codon (UAA-->CAA) that allows the ribosome to read through into the 3' nontranslated region (NTR).

An experimental study of reflex variability in selective dorsal rhizotomy.

Significant problems regarding the measurement technique currently used to choose nerve roots for sectioning in the selective dorsal rhizotomy procedure have recently been reported. To better understand the source of these problems, a series of six experiments was performed in which the selective rhizotomy technique was applied to cats that were either intact, decerebrate, or spinalized. Measurements were made before and after partial rhizotomy.

Reflex variability in selective dorsal rhizotomy.

The variability of reflex responses during selective dorsal rhizotomy was studied in eight children between the ages of 3 and 7 years. For a given dorsal root or rootlet, the electrical reflex threshold and response varied considerably when observed over several minutes. Changes in electrode pressure, mechanical dissection of the root, and reflex spatial facilitation were all found to contribute to the variability.

Glucocorticoid and mineralocorticoid receptors in rat neocortical and hippocampal brain cells in culture: characterization and regulatory studies.

Glucocorticoid and mineralocorticoid binding sites were characterized in cell cultures derived from neocortical and hippocampal brain tissue from fetal (E18) rats. Specific and saturable binding was detected in living cells with a sensitive whole cell binding method using [3H]dexamethasone ([3H]DEX) and [3H]aldosterone ([3H]ALDO) (in the presence of RU 28362, a selective glucocorticoid receptor (GR) agonist) as ligands for the measurement of glucocorticoid and mineralocorticoid receptors (MRs), respectively. Specific corticosteroid binding was demonstrated as early as day 4 in culture in neocortical cells, with a time-dependent increase in binding sites during further culturing time.

Evoked potentials in infant brainstem syndrome associated with Arnold-Chiari malformation.

This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (SEPs) to the assessment of brainstem dysfunction in infants with myelomeningocele and Arnold-Chiari malformation. 16 infants under one year of age were studied. Six had infant brainstem syndrome (IBS).

Preparation of TEM foils from Nb-10 a/o Si.

Ductile phase toughened composites contain phases with significantly different physical properties. Consequently, these phases thin at different rates depending on the sample preparation procedure. A new TEM foil preparation method for the ductile phase toughened Nb-10 a/o Si material has been developed.

Human alpha-globin gene expression is silenced by terminal truncation of chromosome 16p beginning immediately 3' of the zeta-globin gene.

The high level expression of the human alpha-globin genes in erythroid tissue appears to require a set of DNaseI hypersensitive sites located upstream of the human alpha-globin gene cluster. These sequences, termed the locus control region (LCR), include two erythroid specific and a number of less restricted DNaseI hypersensitive sites. In this report we describe an individual with alpha-thalassemia associated with a truncation of the short arm of chromosome 16 that removes the LCR region and inactivates the adjacent intact alpha-globin genes.

Molecular basis for alpha-thalassemia associated with the structural mutant hemoglobin Suan-Dok (alpha 2 109leu----arg).

Hemoglobin (Hb) Suan-Dok (alpha 109Arg) is a rare alpha-globin structural mutation that is linked to an alpha-thalassemia (alpha-thal) determinant. When inherited in trans to an alpha-thal-1 mutation (-), it results in Hb H disease associated with low levels (9%) of the Suan-Dok Hb. The nature of the thalassemic defect associated with the alpha SD mutation has been investigated by structural and functional studies.

Inactivation of human alpha-globin gene expression by a de novo deletion located upstream of the alpha-globin gene cluster.

Synthesis of normal human hemoglobin A, alpha 2 beta 2, is based upon balanced expression of genes in the alpha-globin gene cluster on chromosome 16 and the beta-globin gene cluster on chromosome 11. Full levels of erythroid-specific activation of the beta-globin cluster depend on sequences located at a considerable distance 5' to the beta-globin gene, referred to as the locus-activating or dominant control region. The existence of an analogous element(s) upstream of the alpha-globin cluster has been suggested from observations on naturally occurring deletions and experimental studies.

Cartilage-specific 5' end of chick alpha 2(I) collagen mRNAs.

Chondrocytes grown in suspension contain both type I and type II collagen mRNAs, yet synthesize only type II collagen. The inability of chondrocytes to synthesize the alpha 2 subunit of type I collagen, alpha 2(I), results from a severely reduced translation elongation rate (Bennett, V.D.

Disturbances of brain maturation and neurodevelopment during chronic renal failure in infancy.

Fifteen infants with moderate to severe congenital renal disease were prospectively studied by serial renal, neurodevelopmental, neurophysiologic, and anthropometric assessments. The observation period ranged from 3 to 25 months (mean = 10.9).

Granular cell myoblastoma of the parapharyngeal space.

A granular cell myoblastoma of the parapharyngeal space is presented. Although uncommon, this neoplasm of controversial origin must be considered in the differential diagnosis of all nonenhancing parapharyngeal space masses.

Unexpectedly long 14S ribosomal RNA gene in Tetrahymena mitochondria.

Extraction of RNA from Tetrahymena mitochondrial ribosomes yields several RNA species, including a "large" 21S molecule, a "small" 14S molecule, a 7S molecule, and other smaller RNAs. The molecular weight of the 14S rRNA indicates that it is about 1,300 bases in length. We have sequenced the 14S rRNA gene and, by aligning our sequence with that of the corresponding small rRNA from E.

Pattern-reversal visual-evoked potentials in the diagnosis of amblyopia in children.

We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the diagnosis of amblyopia. Twenty-seven children with anisometropic amblyopia and four children without amblyopia participated. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained by conventional psychometric methods.

Progressive sensorineural hearing loss in survivors of persistent fetal circulation.

The purpose of this study was to discover whether sensorineural hearing loss was a significant complication in survivors of persistent fetal circulation. Eleven patients were followed to 36 months. Hearing assessments were performed on at least two occasions using brain stem auditory evoked response testing and behavioral audiometry.

Applicability of depression scales to the old old person.

Depression is a major health problem in the elderly. The existing literature indicates that depression may be qualitatively different in this population. For example, a condition said to be prevalent among the elderly is masked depression which is marked by a cluster of vegetative symptoms without prominent dysphoria or guilt.

[In vitro and in vivo effect of gold thioglucose on the insulin- and glucagon-secretion of the isolated perfused rat pancreas].

Effects of gold thioglucose on the insulin and glucagon secretion by the isolated perfused pancreas of Wistar rats in vivo and in vitro Gold thioglucose (GTG), hitherto administered predominantly to mice can also be used in rats in a non toxic dosage, if GTG is injected intravenously (i.v.) together with sodium hexobarbital.

A double blind study of vitamin B6 in Down's syndrome infants. Part 2--Cortical auditory evoked potentials.

Cortical auditory evoked potentials (CAEPs) were recorded at 1 and at 3 years of age in 19 children with Down's syndrome participating in a double blind trial of vitamin B6 and placebo begun in early infancy and continued for 3 years. CAEPs have previously been shown to have abnormally high amplitude in Down's syndrome patients. The CAEPs of the patients in the B6-treated and placebo groups were compared.