Constrictive pericarditis.
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Cardiac Catheterization↗
Biomedical subjects
J M Kiernan
Publications and source records attributed to J M Kiernan.
Multiple widely spaced elements determine the efficiency with which a distal cistron is expressed from the polycistronic pregenomic RNA of figwort mosaic caulimovirus.
The polycistronic expression mechanism of the plant pararetrovirus figwort mosaic caulimovirus (FMV) depends upon cis-acting elements present in its pregenomic RNA and a trans-acting protein (P6) which is expressed from a monocistronic subgenomic RNA. Using transient expression of FMV-derived polycistronic reporter constructs in Nicotiana edwardsonii cell suspension protoplasts, we further analyzed the cis-acting elements involved in polycistronic expression. A cis-acting element located within the first 74 nucleotides of the 7,954-nucleotide pregenomic RNA appears to be essential for P6 to transactivate expression of an internal cistron. Expression of this internal cistron, in the presence of P6, is greatly enhanced by the combined presence of two cis-acting elements located at the 3' end of the polycistronic RNA. Surprisingly, deletion of the most upstream of these two 3' cis-acting elements exposed a negative-acting element located internally on the polycistronic RNA, at the 3' end of open reading frame I. The action of both this negative-acting internal element and the positive-acting 3' elements is more pronounced when the large 5' untranslated leader region is present. This indicates that the 5' untranslated leader region is central to regulation of the FMV gene expression mechanism. Although a limited set of elements suffices to direct polycistronic expression in this eukaryotic system, a complex interplay between elements is involved in the spatial regulation of the genes present on the pregenomic RNA of FMV.
Caulimovirus↗
Efficient translation of distal cistrons of a polycistronic mRNA of a plant pararetrovirus requires a compatible interaction between the mRNA 3' end and the proteinaceous trans-activator.
Caulimoviruses, a type of plant pararetrovirus, employ a highly unusual mechanism to express the multiple cistrons of their pregenomic RNA. It involves translation of a polycistronic mRNA utilizing cis-acting viral RNA sequences and a transacting virus-encoded protein (P6). In addition to its role in polycistronic translation, the translational trans-activator protein P6 also activates its own expression from a monocistronic subgenomic RNA. Using Nicotiana Edwardsonii cell suspension protoplasts, we analyzed the ability of P6 proteins from three different caulimoviruses to activate viral RNA-based reporter constructs. Cis-acting elements present in figwort mosaic caulimovirus (FMV) are functional not only in the presence of the cognate P6 activator protein, but also in the presence of the heterologous activators from cauliflower mosaic caulimovirus (CaMV) and peanut chlorotic streak caulimovirus (PCISV). However, when 3' cis-acting elements essential for efficient polycistronic expression of FMV are replaced by their counterparts from PCISV, reporter gene expression is only observed in the presence of PCISV P6. Derepression of monocistronic reporter constructs tailed with FMV or CaMV 3' proximal sequences is less efficient in the presence of PCISV P6 than with either FMV or CaMV P6, but more efficient when the constructs contain a cognate PCISV 3' cis-element. Efficient expression of polycistronic and monocistronic caulimovirus mRNAs in plant cells thus requires compatible interactions between P6, a translational trans-activator, and its cognate cis-element at the 3' end of the mRNA.
Caulimovirus↗
Timing of ventricular septal rupture after acute myocardial infarction and its relation to thrombolytic therapy.
The clinical and treatment characteristics of 71 patients who had acute myocardial infarction complicated by ventricular septal rupture were assessed retrospectively. A history of hypertension was strongly associated with "early" septal rupture (p < 0.001); other clinical and treatment characteristics, including the use and timing of thrombolytic therapy, were not.
Aged↗
The putative zinc finger of a caulimovirus is essential for infectivity but does not influence gene expression.
Plant pararetroviruses, such as caulimoviruses, and animal retroviruses have in common the presence of a highly conserved arrangement of cysteines and a histidine in the precursor of the capsid protein. The composition of these amino acids resembles a zinc finger element, a structure that is common to a class of eukaryotic proteins that regulate gene expression. The role of the putative zinc finger in the life-cycle of caulimoviruses was investigated by introducing specific mutations in the coat protein coding region of a cloned and infectious form of figwort mosaic virus, a caulimovirus. This mutated viral genome, which no longer encoded the conserved cysteine and histidine residues, was not infectious in plants. Transient expression assays in protoplasts showed that expression of a reporter gene inserted at different places in the genome was not detectably influenced by the coat protein or its putative zinc finger. It appears that the zinc finger-like element of caulimoviruses is not involved in the regulation of gene expression. These observations support a model which predicts a function of the zinc finger in specific recognition and packaging of viral RNA into virions prior to reverse transcription.
Amino Acid Sequence↗
Changes in left ventricular systolic function that accompany rejection of the transplanted heart: a serial radionuclide assessment of fifty-three consecutive cases.
To examine the functional changes that accompany the development of rejection of the orthotopically transplanted heart, radionuclide ventriculograms, right heart catheterizations, and endomyocardial biopsies were performed at weekly intervals during the posttransplantation hospitalization of 53 consecutive transplant recipients. Left ventricular ejection fraction decreased in those (n = 10) who had sequential biopsies that changed from no rejection to moderate rejection (63% +/- 7% to 57% +/- 7% respectively, p = 0.007). There was an associated decrease in the peak ejection rate (4.4 +/- 1.0 to 3.9 +/- 0.8 end-diastolic volumes per second, p = 0.008) and an increase in the time to peak ejection rate (137 +/- 27 msec to 153 +/- 20 msec, p = 0.004) that accompanied the development of rejection. There was a similar decrease in left ventricular ejection fraction in those (n = 9) who had sequential biopsies that changed from no rejection to mild rejection (63% +/- 6% to 59% +/- 8%, p = 0.009). Only two of 19 patients whose biopsies changed from no rejection to either mild or moderate rejection did not have an associated decrease in ejection fraction. In patients who had a biopsy that showed definite rejection, which was then followed by histologic resolution after treatment (n = 11), left ventricular ejection fraction increased from 56% +/- 8% to 61% +/- 8%, p = 0.03. There were no significant changes in any of the parameters of diastolic function or in any of the hemodynamic parameters measured, which were associated with either the development or resolution of rejection.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
A controlled clinicopathologic study of myocardial fibrosis in systemic sclerosis (scleroderma).
Clinicopathologic correlations of myocardial fibrosis were examined in 54 autopsied patients with scleroderma and 54 age and sex matched autopsy controls. Thirty eight (70%) of the patients with scleroderma had myocardial fibrosis compared to 20 (37%) of the controls (p less than 0.005). There was no significant difference in the prevalence of contraction band necrosis in the patients with scleroderma (22%) compared to controls (17%). Patients with scleroderma with left ventricular dysfunction in the absence of other causative factors clinically had a greater prevalence of both advanced myocardial fibrosis (60%) and contraction band necrosis (40%) than did the other patients with scleroderma or the controls. We conclude that patients with scleroderma with the greatest likelihood of advanced myocardial fibrosis can be identified clinically, and their findings are consistent with the presence of microvascular coronary vasospasm, a "myocardial Raynaud's phenomenon."
Adult↗
Differential effects of lesions in medial and dorsal raphe of the rat: latent inhibition and septohippocampal serotonin levels.
Rats received either 0 or 30 preexposures to a tone which was later used as a conditioned stimulus (CS) in a two-way avoidance task. Tone preexposure resulted in retarded conditioning in normal animals and animals with dorsal raphe lesions. This latent inhibition effect, however, was not present in animals with medial raphe lesions. The failure of CS preexposure to retard conditioning in animals with medial raphe lesions was not due to differences in auditory sensitivity or shock reactivity. Biochemical analysis indicated that whereas medial raphe lesions significantly reduced serotonin in the septohippocampal complex, dorsal raphe lesions had no such effect. The results are discussed in terms of the differing roles of the mesolimbic and mesostriatal serotonergic systems in learning to ignore irrelevant stimuli.
Acoustic Stimulation↗