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Biomedical subjects

E J Baker

Publications and source records attributed to E J Baker.

85 records · Page 5Linked to original sources
PubMed1982

Nonrandom distribution of histone mRNAs into polysomes and nonpolysomal ribonucleoprotein particles in sea urchin embryos.

In the early sea urchin embryo, newly synthesized cytoplasmic histone mRNA is found both on polysomes and free of ribosomes as nonpolysomal messenger ribonucleoprotein particles (free RNPs). The distribution of newly synthesized histone mRNAs between translating and nontranslating compartments is nonrandom and dependent on the developmental stage. Gel electrophoresis and autoradiography of polysomal and free RNP RNA from embryos at various stages show that (i) the fraction of total newly synthesized histone mRNA that is in polysomes is greater than the fraction of total newly synthesized poly(A)+mRNA that is in polysomes, at all stages examined, and (ii) among the five histone mRNAs. H1 mRNA and H4 mRNA are relatively more enriched in the free RNPs than are the mRNAs for H2A, H2B, and H3. These data suggest that histone mRNA, as a class, is more efficiently utilized as a template than the average mRNA and, of the cytoplasmic histone mRNAs, the mRNAs for histones H2A, H2B, and possibly H3 are selected more frequently for translation than those for H1 and H4. Cell-free translations of polysomal and free RNP RNAs yield different ratios of in vitro histone products, consistent with the RNA distribution data. To test the possibility that the in vivo distribution of the histone mRNAs is the consequence of different intrinsic initiation capabilities of the individual mRNAs, ribosome-binding assays were carried out and unequal binding abilities of the histone mRNAs in the reticulocyte lysate were shown. A translational level component in the regulation of histone synthesis in the sea urchin embryo is indicated.

Animals↗
PubMed1978

Surgery for coccidioidomycosis in 52 diabetic patients with special reference to related immunologic factors.

Fifty-two diabetic patients who underwent pulmonary surgery for coccidioiodmycosis were evaluated by a retrospective study which included classification by stage of disease, status of insulin dependency, and reaction to coccidioidin skin test. The insulin-dependent diabetic patient had a fourfold increase in the incidence of more severe (progressive) disease. Perioperative therapy with amphotericin B may be of value in the adult surgical candidate with progressive disease but is not necessary or desirable in the juvenile diabetic patient. Coccidioidomycosis is a disease of relative immunocompromise, and a negative skin test should herald such compromise and support a decision for surgery. Such surgery in the progressive stages should be totally extirpative. The presence of inadequately resected disease may adversely affect subsequent immunologic resistance of the host.

Adult↗
PubMedDate not supplied

Evaluation of pulmonary artery anatomy using magnetic resonance: the importance of multiplanar and oblique imaging.

Pulmonary artery anatomy was studied in 36 patients (age range 12 days to 12.83 years, mean 2.9 years) with right ventricular outflow tract obstruction over a 3-year period using a 1.5 Tesla Magnetic Resonance system. Gated spin-echo sequences were obtained in each patient. Image planes used were straight and oblique transverse, oblique coronal, and oblique sagittal. The studies were analyzed retrospectively and comparative angiographic, surgical, and postmortem data was available in all cases. As previously noted with other imaging modalities, multiple views and oblique cuts were found to increase significantly the quality and accuracy of the information acquired. In 12 of the 15 patients who had axial and coronal imaging of both branch pulmonary arteries, the pulmonary arteries were unequivocally demonstrated to at least the first hilar branch. However, early in our experience we missed a number of branch stenoses that developed following surgical anastomoses. These mistakes were caused by inadequate or inappropriate slice acquisition. Magnetic resonance is an important technique for imaging pulmonary arteries. Careful use of the appropriate imaging planes is essential for accurate demonstration of the anatomy.

Angiography↗
PubMedDate not supplied

Evaluation of myocardial perfusion using positron emission tomography in infants following a neonatal arterial switch operation.

This study was performed to examine the use of positron emission tomography (PET) as a method of evaluating myocardial perfusion after the arterial switch operation for correction of transposition of the great arteries. Eleven asymptomatic patients (median age 2.3 years, range 1.3-4.3 years) post successful neonatal arterial switch repair for transposition underwent cardiac PET scanning using N(13) ammonia before and after dipyridamole infusion. Reconstructed data from static scans were analyzed for regional perfusion defects before and after pharmacological stress. Simultaneous assessment of coronary flow before and after stress was performed using a Patlak graphical analysis of data from dynamic scans. Results obtained from PET scanning were correlated with patterns of coronary artery anatomy, electrocardiogram (ECG) recordings, and echocardiographic evaluation. PET scanning demonstrated normal distribution of myocardial perfusion before and after stress in all but one patient, who was found to have a discrete inferior transmural perfusion defect. The defect was well correlated with perioperative ECG changes and a complicated postoperative course. Myocardial blood flow before dipyridamole (0.690 ml/min/g) was similar to reported adult rest values. There was a small but significant (p < 0.002) increase in myocardial blood flow after dipyridamole stress with a mean coronary flow reserve of 1.19 (+/-0.103). Echocardiographic evaluation failed to demonstrate significant wall motion abnormalities in any of the patients. Cardiac PET scanning is a reliable noninvasive method for evaluation of myocardial perfusion in small children. In this study, the incidence of myocardial perfusion defects after the arterial switch operation is lower than previously reported. The data obtained concerning coronary flow and coronary flow reserve after the arterial switch need to be interpreted with caution because normal data in children are not available.

Ammonia↗
PubMedDate not supplied

Angiotensin-converting enzyme (ACE) gene polymorphism in type II diabetic patients with increased albumin excretion rate.

Approximately one in three patients with diabetes is at risk of developing kidney disease, despite current methods of treatment. It has long been suspected that diabetic kidney disease has a genetic basis, but this has been difficult to prove. Polymorphisms of the angiotensin-converting enzyme (ACE) gene have been shown to be related to the occurrence of nephropathy in type I diabetic patients. This study showed that there was no association in the ACE genotype frequency and increased albumin excretion rate in type II diabetic patients.

Adult↗
PubMedDate not supplied

Associate degree nursing students: nonintellective differences between dropouts and graduates.

A comprehensive battery of tests designed primarily to measure nonintellective characteristics was administered to 112 students entering five associate degree nursing programs. At the end of two years, analyses of the entrance data revealed significant differences between the 73 graduates (those who completed the program on schedule) and the 32 nongraduates (those who dropped our of the program for various reasons). Seven students who remained in the programs but who had not completed the requirements were not included in the analyses. The data indicated that at the time of entry into their programs, those students who later completed the program on schedule were more mature--older and married, more achievement oriented, responsible, and self-controlled than dropouts. Successful students also manifested more accepting and nonjudgmental attitudes toward other people.

Education, Nursing, Associate↗
PubMedDate not supplied

Prenatal diagnosis and correction of congenital heart defects.

The improvement in heart scanning expertise during the routine obstetric scan has resulted in more congenital heart disease being recognized prenatally. Early diagnosis of severe heart malformation results in the majority of parents choosing to interrupt the pregnancy or allows the mother to give birth in a centre with obstetric and paediatric cardiac facilities.

Aorta, Thoracic↗