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Biomedical subjects

A Wright

Publications and source records attributed to A Wright.

At least 253 records · Page 14Linked to original sources
PubMed1991

Title III services: variation in use within a state.

Using data from Connecticut's management information system for Title III funds, we found, first, that such services are reaching at least one person in every town and thus modestly fulfilling a gateway function; about 9% of Connecticut's elderly use Title III services, with 20% of the oldest old obtaining such services. Nutrition services are reaching the most elderly, both numerically and geographically; among the oldest old (85+), home care service use was most widespread. Indices of use were not statistically related to specific characteristics of the towns' populations (i.e., percentage of elderly, poor, or minority elderly), but small cities and rural towns had the highest use levels. Presence of nutrition sites within the town and service through two of the five area agencies on aging (AAAs) were also correlated with high service use, controlling for the rural-urban continuum. Those two AAAs received the highest per capita amount of Title III funds, based on the state's targeting formulas.

Aged↗
PubMed1990

Transcriptional antitermination in the bgl operon of E. coli is modulated by a specific RNA binding protein.

Regulation of bgl operon expression in E. coli occurs by a mechanism involving antitermination of transcription at two termination sites within the operon. The bglG gene product is absolutely required for this process. Here we provide evidence that BglG is an RNA binding protein that recognizes a specific sequence located just upstream of each of the terminators. The sequence was delimited using a series of specific oligonucleotide probes. Mutational analysis of this sequence indicates that the protein requires a specific RNA secondary structure for recognition. We propose that BglG prevents transcription termination by binding to nascent RNA and blocking formation of the terminator structure.

Bacterial Proteins↗
PubMed1990

Regulation of activity of a transcriptional anti-terminator in E. coli by phosphorylation in vivo.

Expression of the bgl operon of Escherichia coli is regulated in vitro by phosphorylation and dephosphorylation of a positive regulatory protein, BglG, which functions in its nonphosphorylated state as a transcriptional antiterminator. The degree of phosphorylation of BglG in vivo was shown to be dependent on the cellular levels of BglF protein, which is both the BglG kinase and phosphatase. The degree of phosphorylation of BglG also depended on the presence or absence of a beta-glucoside, the inducer of operon expression. Addition of inducer to cells in growth medium resulted in rapid dephosphorylation of phosphorylated BglG. The bgl operon is thus regulated by a sensory system that modulates gene expression by protein phosphorylation and dephosphorylation in response to the external levels of inducer.

Bacterial Proteins↗
PubMed1990

Scimitar syndrome: cine magnetic resonance imaging demonstration of anomalous pulmonary venous drainage.

A "scimitar" shadow was found on routine chest roentgenography in an asymptomatic patient. Evaluation with cine magnetic resonance imaging demonstrated an anomalous pulmonary vein draining into the inferior vena cava below the diaphragm. The diagnosis of scimitar syndrome was confirmed and successfully repaired at operation. Cine magnetic resonance imaging may be of considerable value in the assessment of congenital pulmonary venous abnormalities and may provide an alternative to more traditional invasive diagnostic techniques in certain circumstances.

Adult↗
PubMed1990

Imaging cholesteatoma.

Acquired cholesteatoma of the middle ear is usually diagnosed by otoscopy and treated by exploratory surgery. The role of imaging for such cases is as controversial now as it was 10 years ago, despite significant improvements in spatial and contrast resolution resulting from computerised sectional imaging. We examined 16 cases of straightforward acquired middle ear cholesteatomas with MR as well as high resolution CT scanning to assess the possibilities for tissue characterisation. Cases of the much rarer but more important congenital cholesteatoma of the petrous pyramid with a normal eardrum were also diagnosed by CT and MRI. Magnetic resonance will distinguish cholesteatoma from granulation tissue, fluid and the cholesterol granuloma in the middle ear but this differentiation is of no practical value. An expansile lesion in the petrous apex is most likely to be a cholesteatoma or cholesterol granuloma and is well shown but not differentiated by CT. The two types have quite different characteristics on MR protocols and this is important for planning surgical procedures.

Child↗
PubMed1990

Factor XIIIa in nodular malignant melanoma and Spitz naevi.

The distribution of factor XIIIa-positive dermal dendritic cells was studied in a series of nodular malignant melanomas and compared with that seen in Spitz naevi. Two patterns of distribution were recognizable: (a) diffusely spread through the tumour and (b) located mainly at the periphery of the tumour. These did not correlate with the diagnosis of melanoma or Spitz naevus and the distribution appeared to be a function of growth pattern of the tumour. The diffuse pattern was the most common regardless of diagnosis and the distribution of factor XIIIa-positive cells is the same in malignant melanoma and Spitz naevi.

Dendritic Cells↗
PubMed1990

Obstructive sleep apnoea in children undergoing routine tonsillectomy and adenoidectomy.

Sleep screening was used to discover the incidence of sleep apnoea in 50 children undergoing routine adenotonsillectomy for recurrent upper respiratory tract infections, randomly selected from the waiting list. Preoperative assessment included a detailed parental history, physical examination, and lateral cephalometry, in order to identify factors that might alert the clinician to a diagnosis of obstructive sleep apnoea. There were 2 equal groups of snorers and non-snorers (grade 0); 1 patient was found to have the sleep apnoea syndrome (IV), 9 patients had obstructive snoring with apnoeic episodes (III), 3 patients had snoring with a disrupted sleep pattern (II), and 12 patients snored with no disruption of sleep (I). In identifying patients with apnoea, a history of snoring was unhelpful, whereas one of breathing irregularities was found to be highly specific. Nasal obstruction correlated poorly; however, there was a significant relationship between tonsillar position and size and sleep grade (Chi-squared P less than 0.01). Stepwise regression analysis showed a large contribution to the grading was made by the size of the oropharyngeal airway measured by lateral cephalometry. The children in grade II-IV were re-studied 3 months post-operatively and all reverted to grades 0 or I.

Adenoidectomy↗
PubMed1990

Molecular analysis of the Haemophilus influenzae type b pilin gene.

A Haemophilus influenzae DNA library was prepared in the vector lambda EMBL3, and recombinant phage were screened for the pilin gene (pil) using a synthetic oligonucleotide. Southern blot analysis of the positive clones revealed a 2.5kb PstI/PvuI fragment that hybridized with the oligonucleotide probe. This fragment was subcloned into pBR322 and sequenced. The nucleotide sequence disclosed an open reading frame of 653 bases. The deduced amino acid sequence corresponded with the known amino acid sequence of the purified pilin protein. Primer extension analysis using total RNA from piliated H. influenzae cells delineated a start site for the gene, -10 and -35 promoter regions, and a ribosome-binding site. No transcripts were seen with the RNA derived from a non-piliated strain. Southern blots of DNA from a number of H. influenzae strains revealed homology with the pil structural gene. DNA from a non-piliated strain of H. influenzae also hybridized with the pil probe. Transcriptional and translational studies were performed in Escherichia coli with plasmids containing: (i) the pil gene on the 2.5 kb PstI/PvuI fragment, (ii) the pil gene fused to the phoA gene, and (iii) the pil gene present on a 12.2 kb insert containing extensive H. influenzae DNA flanking the pil gene. The results suggest that the H. influenzae pil gene is expressed in Escherichia coli, but from a promoter other than the one used in H. influenzae.

Alkaline Phosphatase↗
PubMed1990

Localization of the cleavage site specificity determinant of Haemophilus influenzae immunoglobulin A1 protease genes.

Immunoglobulin A1 (IgA1) proteases are produced by a number of different species of bacteria which cause infection at human mucosal surfaces. The sole substrate of these proteases is human IgA1. Cleavage is within the hinge region of IgA1, although there is variability in the exact peptide bond within the hinge region that is cut by a particular protease. The cleavage site of the Haemophilus influenzae type 1 protease is located four amino acids from the cleavage site of the type 2 enzyme. In this study, the region of the H. influenzae IgA1 protease gene (iga) that determines the cleavage site specificity was localized through the comparison of the type 1 and type 2 genes and the construction and analysis of type 1-type 2 hybrid genes. The hybrid genes were generated by in vivo and in vitro techniques which facilitated the selection and screening of randomly generated hybrids. The cleavage site determinant was found to be within a 370-base-pair region near the amino-terminal coding region, in one of two large areas of nonhomology between the two types of H. influenzae iga genes. DNA sequence analysis of the cleavage site determinant and surrounding regions did not reveal a simple mechanism whereby one enzyme type could be converted to the other type. Comparison of the type 2 gonococcal IgA1 protease gene to the two Haemophilus genes revealed a significant amount of homology around the cleavage site determinant, with the two type 2 genes showing greater homology.

Animals↗
PubMed1990

Receptors for human interferon alpha on bovine cells: specificity and tissue distribution.

Human interferon alpha 1 (HuIFN alpha 1) is known to protect bovine as well as human cells against viral infection. Hence, we investigated the specificity and tissue distribution of receptors for HuIFN alpha 1 on various cells. [35S]HuIFN alpha 1 bound specifically to homogenates of bovine tissues and particularly to bovine liver, but there was also specific binding to spleen, kidney, brain, adrenal gland, lung, thymus, skeletal muscle, heart, mammary gland and testis. There was no difference in the degree of binding of HuIFN alpha to foetal or adult liver. Competitive binding experiments showed that bovine interferon alpha C (BoIFN alpha C) competed with HuIFN alpha 1 for binding to a bovine liver plasma membrane preparation, indicating that these two IFNs bind to the same receptor. An 35S-labelled IFN alpha 1-receptor complex was isolated from bovine liver extracts by SDS/polyacrylamide gel electrophoresis, and shown to have a molecular weight of 153 kDa. Isolation of the bovine IFN alpha receptor would be a feasible approach to the characterization of the HuIFN alpha receptor.

Animals↗
PubMed1990

Regulation of expression of the dnaA gene in Escherichia coli: role of the two promoters and the DnaA box.

The dnaA gene of Escherichia coli specifies a product that is a key element in the initiation of DNA replication. Expression of dnaA occurs from two promoters, 1P and 2P, which flank a DnaA protein binding site (DnaA box). In this paper we describe the effects of DnaA box mutations on transcription from the two promoters, measured with the use of dnaA-galK gene fusions. All of the mutations examined led to a five-fold increase in expression from the upstream promoter, 1P, suggesting that expression from this promoter is negatively autoregulated by binding of DnaA protein to the box. The same mutations led to a decrease in expression from promoter 2P, suggesting that the DnaA box plays a role in activating promoter 2P under normal conditions. Overproduction of DnaA protein, above normal physiological levels, led to decreased transcription from both promoters. We present evidence from analysis of both dnaA mRNA and DnaA protein that promoter 2P is subject to growth rate-dependent control and that this promoter, but not promoter 1P, is completely shut off in the stationary phase of growth.

Bacterial Proteins↗
PubMed1990

Deletions in patients with classical choroideremia vary in size from 45 kb to several megabases.

Making use of the p1bD5 probe (DXS165), we have isolated several markers from the choroideremia locus by chromosomal jumping, preparative field-inversion gel electrophoresis, and cloning of a deletion junction fragment. With these clones we were able to identify and characterize eight deletions in 69 choroideremia patients investigated. The deletions are heterogeneous, in both size and location. The smallest deletion (patient LGL1134) comprises approximately 45 kb of DNA, whereas the largest ones (patients 25.6 and LGL2905) span a DNA segment of at least 5 megabases, which is comparable in size to the smallest deletion detected in a TCD patient (patient XL45) showing a complex phenotype. The TCD deletions encompass variable parts of 150-200-kb DNA segment that is flanked by p1bD5 (DXS165) at the centromeric side and by pZ 11 at the telomeric side. The deletions in patients 33.1, LGL1101, and LGl1134 do not span a translocation breakpoint which was previously mapped on the X chromosome of a female with TCD. The clones isolated from the TCD locus are valuable diagnostic markers for deletion analysis of patients or carrier females. In addition, they should be useful for the isolation of expressed sequences that are part of the TCD gene.

Blotting, Southern↗