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Biomedical subjects

K McBride

Publications and source records attributed to K McBride.

At least 37 records · Page 2Linked to original sources
PubMed1993

The self-perceptions and attributions of attention deficit hyperactivity disordered and nonreferred boys.

Compared the self perceptions and attributions of attention deficit hyperactivity disordered (ADHD) and control boys. The ADHD boys viewed themselves as no worse than control boys on self-perceived competence and global self-worth, especially when internalizing symptomatology was taken into account statistically through covariance analyses. In terms of attributions, the ADHD boys were more likely to take responsibility for social successes and less likely to take responsibility for social failures than the control boys. Although the ADHD boys scored significantly higher on the Children's Depression Inventory, this difference was no longer significant when items dealing with behavior, school, and social problems were excluded. The results are discussed in terms of their implications for understanding how the attributions and self-perceptions of ADHD boys may mediate their performance in challenging academic and social situations.

Adolescent↗
PubMed1993

fos/jun repression of cardiac-specific transcription in quiescent and growth-stimulated myocytes is targeted at a tissue-specific cis element.

Unlike that of skeletal muscle cells in which growth and differentiation appear mutually exclusive, growth stimulation of cardiac cells is characterized by transient expression of early response nuclear proto-oncogenes as well as induction of several cardiac-specific markers. This observation led to the speculation that these proto-oncogenes, particularly c-fos and c-jun, might act as positive regulators of cardiac transcription. We have examined the role of c-jun and c-fos in basal and growth-stimulated cardiac transcription, using the cardiac-specific atrial natriuretic factor (ANF) gene as a marker. The results indicate that c-jun and c-fos are negative regulators of ANF transcription. Inducers of jun and fos activity, such as mitogens and growth factors, inhibited endogenous ANF transcripts. In transient cotransfection assays, jun and fos were able to trans-repress the ANF promoter in both quiescent and alpha 1-adrenergic stimulated myocytes. This repression was specific to myocyte cultures and was not observed in nonmuscle cells. Deletion analysis indicated that repression does not require typical AP-1-binding sites (tetradecanoyl phorbol acetate response elements) or serum response elements but is targeted at a cardiac-specific element within the ANF promoter. Various Fos-related proteins, including Fra-1, Fos B, and v-Fos, were able to trans-repress ANF transcription. In addition, C-terminal c-fos mutants which no longer repress transcription of such early growth response genes as c-fos and EGR-1 retained the ability to repress ANF transcription. Repression by c-jun occurs via the N-terminal activation domain and does not require the DNA-binding domain, suggesting that proto-oncogene repression involves interaction with one or more limiting cardiac-specific coactivators.

Animals↗
PubMed1992

The DNA sequence of equine herpesvirus-1.

The complete DNA sequence was determined of a pathogenic British isolate of equine herpesvirus-1, a respiratory virus which can cause abortion and neurological disease. The genome is 150,223 bp in size, has a base composition of 56.7% G + C, and contains 80 open reading frames likely to encode protein. Since four open reading frames are duplicated in the major inverted repeat, two are probably expressed as a spliced mRNA, and one may contain an internal transcriptional promoter, the genome is considered to contain 76 distinct genes. The genes are arranged collinearly with those in the genomes of the two previously sequenced alphaherpesviruses, varicella-zoster virus, and herpes simplex virus type-1, and comparisons of predicted amino acid sequences allowed the functions of many equine herpesvirus 1 proteins to be assigned.

Amino Acid Sequence↗
PubMed1991

Immunocytochemical localization of phospholipase C-gamma in rat embryo fibroblasts.

Rat embryo fibroblasts (REF52) exhibit a distinctive, transformation-sensitive distribution of alpha-protein kinase C (alpha-PKC). Receptor-mediated activation of phospholipase C (PLC)-gamma generates diacylglycerol, the major cellular activator of PKC. Immunofluorescence techniques were used to investigate the subcellular localization of two PLC isozymes (PLC-gamma and PLC-delta) in normal and simian virus 40-transformed REF52 cells to determine (i) if PLC colocalizes with alpha-PKC and (ii) if PLC isozyme distribution is sensitive to transformation. PLC-delta was not detected in either cell type. In REF52 cells, PLC-gamma was associated with the actin cytoskeleton and was evenly distributed along the length of the actin microfilaments. PLC-gamma was coincident with alpha-PKC at the points where the filaments are anchored to the membrane (i.e., the focal contacts). Cytoskeletal association of PLC-gamma was not transformation sensitive, although the actin cytoskeleton was more disordered in simian virus 40-transformed cells. In REF52 cells, platelet-derived growth factor induced tyrosine phosphorylation of both soluble and cytoskeletal PLC-gamma. Tyrosine phosphorylation of PLC-gamma did not seem to be a determinant of its subcellular localization, but there was a detectable increase in cytoskeleton-associated PLC-gamma in response to platelet-derived growth factor treatment.

Animals↗
PubMed1991

Platelet-derived growth factor activates phospholipase D and chemotactic responses in vascular smooth muscle cells.

Platelet-derived growth factor (BB dimer; PDGF-BB) stimulates a mitogenic response in A-10 vascular smooth muscle cells. In addition, PDGF-BB stimulates phospholipase D activity against phosphatidylcholine in A-10 cells. This response was observed as a rapid metabolism of phosphatidylcholine to phosphatidate and choline; a subsequent metabolism generates sustained levels of diacylglycerol. The accumulation of phosphatidylethanol, a transphosphatidylation product of phospholipase D, was obvious in PDGF-treated cells. PDGF-BB also stimulates a chemotactic response in A-10 cells. The concentrations of PDGF-BB required to stimulate mitogenesis, phospholipase D activity and chemotaxis are similar. This finding shows that PDGF induces a variety of cellular responses and suggests that these responses may share common metabolic pathways. That conception was tested by investigating the activity of the different PDGF dimers. PDGF-AA had little or no activity in A-10 cells for any of the responses measured. PDGF-AB and PDGF-BB were equally potent in stimulating mitogenic responses. However, the AB heterodimer was only half as active as PDGF-BB with respect to activation of phospholipase D and chemotactic responses. These results demonstrate that PDGF stimulates phospholipase D in vascular smooth muscle cells. In addition, the data indicate that different PDGF dimers can transduce varying signals and suggest a link between the mechanisms by which PDGF-BB activates phospholipase D and the chemotactic response.

Animals↗
PubMed1991

Radiologically controlled balloon dilatation of rectal strictures.

Rectal stricture is a well recognized complication following anterior resection. It is traditionally managed with metal dilators or resection. This paper describes the use of balloon dilatation for benign anastomotic rectal strictures. Eight patients were included in the trial. Only one dilatation was necessary in four patients while the remaining four patients required further dilatation for relief of symptoms. The mean diameter of the stricture increased from 7.2 mm to 17.0 mm post-dilatation. There were no complications associated with the procedure. Balloon dilatation is a safe and effective method of treating benign anastomotic rectal strictures.

Anastomosis, Surgical↗
PubMed1991

Sympathetic denervation of the iris dilator in noninsulin-dependent diabetes.

Twenty-three subjects with noninsulin-dependent diabetes mellitus (NIDDM) and 23 age- and sex-matched controls were tested for sympathetic denervation of the iris dilator by comparing the mydriatic effect of the combination of 1% phenylephrine and 1% tropicamide with that of 1% tropicamide alone. Most of the diabetic subjects had no clinical signs of severe diabetic complications. Nine diabetics and two controls showed sympathetic denervation, defined as a 1 mm or greater dilation due the addition of 1% phenylephrine. One of those two controls had a recent history of vascular headache. The diabetics with pupillary neuropathy had higher glycosylated hemoglobin percentages and a history of higher fasting blood sugars (FBS's) than the diabetics with normal pupils. Our results show that pupillary neuropathy can develop in persons with diabetes, often before the other complications of diabetes become manifest.

Adult↗
PubMed1990

PCR cloning and sequence of gastrin mRNA from carcinoma cell lines.

The hypothesis that a gastrin-like peptide is acting as an autocrine growth factor in gastric and colonic carcinoma cell lines requires that the cells should synthesize a gastrin-like mRNA. Although no gastrin mRNA was observed in the gastric line Okajima or the colonic lines HCT 116 or LIM 1215 by Northern blotting, gastrin mRNA was detected by application of the polymerase chain reaction. Two products were observed corresponding to mRNA with and without a 130 bp intron. The sequences of both products were identical to the sequences predicted from the normal human gastrin gene.

Base Sequence↗
PubMed1988

Chloroplast transport of a ribulose bisphosphate carboxylase small subunit-5-enolpyruvyl 3-phosphoshikimate synthase chimeric protein requires part of the mature small subunit in addition to the transit peptide.

Ribulose bisphosphate carboxylase small subunit protein is synthesized in the cytoplasm as a precursor and transported into the chloroplast where the amino-terminal portion, the transit peptide, is removed proteolytically. To obtain chloroplast delivery of the 43-kDa 5-enolpyruvyl 3-phosphoshikimate (EPSP) synthase of Salmonella typhimurium, we constructed fusion proteins between the bacterial EPSP synthase and the ribulose bisphosphate carboxylase small subunit. A fusion protein consisting of the transit peptide fused to the EPSP synthase was not transported in vitro or in vivo into chloroplasts. A second fusion protein consisting of the transit peptide and 24 amino acids of the mature small subunit fused to the EPSP synthase was transported both in vitro and in vivo into chloroplasts. It was processed into two polypeptides of 46 and 47 kDa, respectively. This heterogeneity in processing was not caused by the presence of the aroA start codon, since its removal resulted in the same pattern. Substituting 24 different amino acids for the 24 amino acids of the mature small subunit resulted in a fusion protein that was not transported into the chloroplast. It was concluded that a portion of the mature small subunit was needed for efficient chloroplast delivery.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1986

Can ventilation-perfusion scans accurately diagnose acute pulmonary embolism?

To examine the accuracy of ventilation-perfusion (V/Q) scanning, we retrospectively reviewed pulmonary angiograms and V/Q scans from 150 patients clinically suspected of having pulmonary embolism. Pulmonary emboli were documented by angiography in 56 patients (37%). In seven patients V/Q scans were interpreted as being normal and these seven patients were angiographically negative for emboli. The remainder of the scans were classified as showing a low, moderate, or high probability of emboli, or as indeterminate scans. Among these four abnormal classifications, pulmonary angiography demonstrated emboli in 13.6%, 62.5%, 85.7%, and 18.4% of these patients, respectively. An analysis of these data demonstrates that an unacceptably high error rate would result if V/Q scans alone were relied upon to establish the presence or absence of pulmonary emboli. In view of the high mortality that results when pulmonary emboli are untreated and the relatively low mortality and morbidity of pulmonary angiography, angiography remains an essential diagnostic procedure in patients suspected of having pulmonary embolism.

Acute Disease↗
PubMed1983

Digital subtraction angiography for examination of vessels of the leg: use of a 40-cm image intensifier.

Digital subtraction angiography (DSA) using a 41-cm (16-in.) image intensifier was performed in 144 patients with peripheral vascular insufficiency. In most cases the entire peripheral vascular bed from the renal arteries to the popliteal trifurcation was demonstrated with four intravenous injections and four exposed fields: (a) aorto-iliac, (b) ilio-femoral, (c) femoro-popliteal, and (d) popliteo-tibial. In 90% of cases the procedure was diagnostic in all regions studied, while in 10 it was nondiagnostic in one or more regions for various reasons (myocardial insufficiency, inadequate contrast bolus, or technical failure). Most failures involved the distal arteries. In spite of some limitations, intravenous DSA using a large-field image intensifier may replace conventional angiography in routine preoperative evaluation of peripheral vascular disease, with intra-arterial injections being performed when the intravenous technique is nondiagnostic.

Adult↗