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H C Smith

Publications and source records attributed to H C Smith.

At least 91 records · Page 5Linked to original sources
PubMed1989

Which routine test for kidney function?

Eighty measurements of plasma creatinine concentration, height:creatinine ratio, and plasma beta 2 microglobulin concentration were made on 72 children (age 4 months-18.5 years) with known renal disease. Results were compared with simultaneous measurements of glomerular filtration rate using plasma clearance of 51Cr edetic acid to assess the performance of each test as an initial screening procedure of renal insufficiency. Height:creatinine index less than 2.1 was found to have a higher sensitivity and predictive value of a normal result than the other tests and is therefore the preferred test for a screening procedure.

Adolescent↗
PubMed1989

PTCA in the elderly: results and expectations.

Percutaneous transluminal coronary angioplasty (PTCA) is an excellent and safe alternative mode of revascularization in selected elderly (greater than 65 years) patients. The initial success rate at our institution for elective and non-elective procedures is essentially equal when compared with a younger (less than or equal to 65 years) population. Although the 24-hour mortality of 1.0% was higher during elective PTCA for the elderly versus 0.3% in those 65 and under, this is still very acceptable when compared with coronary artery bypass grafting. In a small number of patients, we found no increased mortality between the two groups during non-elective PTCA. We conclude that PTCA may be the procedure of choice for symptomatic single discrete stenosis in the elderly patient.

Age Factors↗
PubMed1988

Chemical cross-linking of Sm and RNP antigenic proteins.

Nuclear extracts, competent for in vitro premessenger RNA splicing, were chemically cross-linked with thiol-reversible reagents in order to study the organization of proteins within ribonucleoprotein particles (RNPs) containing uridine-rich small nuclear RNAs (UsnRNPs). The distribution of select UsnRNP antigens within cross-linked complexes was determined by Western blotting of diagonal two-dimensional gels. On the basis of calculations from the molecular weights of cross-linked complexes containing UsnRNP common proteins B', B, and D, it is proposed that each of these proteins was associated with UsnRNP common proteins E and G. In addition, D' is proposed to be positioned close to D. The spatial distribution of UsnRNP common proteins was such that B' and B could not be cross-linked to D. The data also suggested that the 63-kDa U1 snRNP specific protein was cross-linked to other U1-specific proteins, particularly C, but not to the UsnRNP common proteins. We propose that part of the UsnRNP core of common proteins contains at least two asymmetrical copies of B':B:D:D':E:G with stoichiometries of 2:1:1:1:1:1 and 1:2:1:1:1:1.

Cell Nucleus↗
PubMed1988

Results of percutaneous transluminal coronary angioplasty for angina pectoris early after acute myocardial infarction.

Between May 1980 and July 1985, 70 patients underwent percutaneous transluminal coronary angioplasty (PTCA) for angina occurring 24 hours after and within 30 days of acute myocardial infarction (32 with Q-wave infarction and 38 with non-Q-wave infarction). One-vessel disease was present in 42 (60%) and multivessel in 28 (40%); the mean ejection fraction was 0.56 (greater than or equal to 0.50 in 77% of patients). PTCA was successful in 56 patients (80%) and after introduction of steerable dilating systems in February 1983 this rate became 86%. The success rate for complete occlusions was 76%. The interval from myocardial infarction to PTCA was similar in patients with successful dilation (12.7 +/- 8.1 days) and those without (13.4 +/- 8.0 days). PTCA failed in 14 patients (20%); 8 underwent emergency coronary artery bypass for acute occlusion and 4 of 6 patients whose lesions could not be crossed had elective bypass surgery. There was 1 operative death. No patient sustained a Q-wave infarction. Three patients had non-Q-wave infarctions after technically successful PTCAs. Mean follow-up was 27 months (6 to 67 months). Of the 56 patients successfully dilated, 14 (25%) had 15 cardiac events during follow-up: death (1), non-Q-wave infarction (2), repeat PTCA (7), coronary bypass (4) and recurrence of severe angina (1). The cumulative mortality was 3% and the reinfarction rate was 7% (no Q-wave reinfarctions). Forty-two (60%) of the 70 patients were free of complicating events acutely and during follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

SnRNP core protein enrichment in the nuclear matrix.

The D protein (16 kDa) is part of a protein core, common to U1, U2, U5, U4/U6 small nuclear RNA containing ribonucleoprotein particles. Monoclonal antibodies reactive with the D protein were used in quantitative dot blotting and Western blotting to demonstrate that this protein was a component of salt resistant nuclear structures and was enriched greater than 3 to 5-fold in RNAase-protected nuclear matrix preparations.

Antibodies, Monoclonal↗
PubMed1988

Use of a metal ring-marked catheter for geometric calibration in quantitative coronary angiography.

Quantitative coronary angiography depends on accurate measurement of catheter shaft diameter for correction of X-ray magnification errors. We compared the use of coronary catheters with a single metal ring (R), inserted during manufacture, with measurements using the edges of the catheter shaft (S) as a calibration mark. Both ring and shaft were 2.50 mm in diameter. On unmagnified X-ray images, the ring measured 2.49 +/- 0.40 mm, and the shaft measured 2.39 +/- .040 mm in diameter. Quantitative coronary angiography using both ring and shaft for calibration provided the same percent stenosis (R:72 +/- 12; S: 71 +/- 13), but stenosis cross-sectional area was 28% different (R: 1.44 +/- .24; S: 1.84 +/- .34 mm2). Use of the catheter shaft for calibration causes overestimation of actual coronary artery dimensions. To prevent this problem, absolute measurements of coronary artery dimensions should be made with metal ring-marked catheters.

Angiocardiography↗
PubMed1988

Reversible chemical cross-linking and ribonuclease digestion analysis of the organization of proteins in ribonucleoprotein particles.

The organization of select proteins within ribonucleoprotein particles containing heterogeneous nuclear and uridine-rich small nuclear RNAs (hnRNP and UsnRNP respectively) was examined by chemical cross-linking and ribonuclease digestion using diagonal two dimensional PAGE and immunoblotting detection systems. Monoclonal antibodies specific for A2, C1 and C2 hnRNP proteins, detected these proteins at gel coordinates which suggested homotypic dimers and trimers of A2 and homotypic trimers, hexamers and larger multimers of C1 and C2. Ribonuclease digestion did not alter the cross-linking properties of hnRNP C1 and C2 proteins but did result in loss of A2 homotypic dimers and trimers. Blots simultaneously reacted with hnRNP specific monoclonal antibodies and autoimmune patient serum (RNP/Sm), or monoclonal antibodies reactive with the U1 snRNP specific 63 kDa protein and/or the UsnRNP common proteins B', B and D revealed no complexes which would indicate interactions between hnRNPs and UsnRNPs. The U1 UsnRNP specific 63 kDa protein appeared not to be cross-linked to UsnRNP common B', B and D proteins. The data also suggested that UsnRNP common protein D was cross-linkable to UsnRNP common proteins D', E and G but not to B' and B. The cross-linking properties of D were unaffected by ribonuclease digestion. In contrast, ribonuclease digestion resulted in an inability to cross-link select complexes containing either B' and B, or p63. The data suggest that both hnRNPs and UsnRNPs are comprised of RNA-dependent and RNA-independent protein-protein interactions.

Cross-Linking Reagents↗
PubMed1987

Comparison of monoplane and biplane assessment of regional left ventricular wall motion after thrombolytic therapy for acute myocardial infarction.

Regional left ventricular (LV) function was assessed using serial biplane orthogonal LV angiograms recorded before and after reperfusion therapy for acute myocardial infarction (AMI) in 24 patients. Improvement in regional LV function was seen in only 5 patients after reperfusion therapy when only the right anterior oblique view was analyzed; improvement in regional wall motion was seen in 14 when biplane views were analyzed. Biplane analysis was particularly important in the 12 patients with right coronary artery occlusion, among whom the right anterior oblique view showed improvement in only 1 patient but the left anterior oblique view showed improvement in 6 patients (p less than 0.05). Biplane analysis is more sensitive than monoplane right anterior oblique analysis alone for detecting improvement in LV function after reperfusion therapy for AMI. However, both views are complementary, adding information about regional function not revealed by either view alone.

Female↗
PubMed1987

Ultrastructural and biochemical comparisons of nuclear matrices prepared by high salt or LIS extraction.

We have directly compared two independently published methods for isolating operationally defined nuclear matrices by studying EM ultrastructure, protein composition and distribution of replicating DNA. Nuclear matrices prepared by extraction with 2 M NaCl consisted of fibrous pore complex lamina, residual fibrillar and granular components of nucleoli and interchromatin granules, and an extensive anastomosing internal fibrous network. These matrices were enriched in high molecular weight nonhistone proteins but were virtually devoid of histones. Consistent with previously published data, newly-replicated DNA was resistant to this high salt extraction. Nuclear matrices prepared by extraction of nuclei with 25 mM lithium 3,5-diiodosalicylate, LIS, also contained fibrous pore complex lamina, but lacked morphologically distinct residual nucleoli and were markedly depleted in internal structure. The reduced amounts and complexity of proteins associated with the LIS matrix were consistent with the ultrastructural data. Moreover, much less newly-replicated DNA was recovered in LIS matrices. The data show that LIS dissociates nuclear ultrastructure and extracts both protein and DNA in proportion to the concentration used, regardless of whether nuclei or high salt nuclear matrices are used as starting material. While the data suggest that LIS may not necessarily be an optimal reagent for preparing nuclear matrices containing internal structural elements from all tissue sources, it may be useful for selectively solubilizing and analyzing components of the nuclear matrix.

Animals↗
PubMed1987

Ribosomal DNA sequences attached to the nuclear matrix.

The organization of rat liver ribosomal DNA (rDNA) as matrix-attached DNA loops was examined using a protocol which fractionates chromatin from discrete regions of DNA loops. Southern blot analysis of matrix-attached and solubilized chromatin DNA fragments demonstrated that rDNA is associated with the matrix via its 5' and 3' nontranscribed spacer sequences (NTS). Although the 45 S rRNA coding sequences were approximately threefold enriched in matrix preparations, the recovery of this DNA (unlike the NTS) was dependent on the extent of nuclease digest and proportional to the length of the matrix-attached DNA fragments. The data suggest that rDNA is organized as matrix-attached DNA loops and only the NTS are directly involved in matrix binding. Further, we demonstrated that while the kinetics and extent of nuclease digestion were similar in all regions of the DNA loops, the nuclease digestion pattern of bulk nuclear and matrix DNA showed a typical nucleosome organization, but the rDNA fragments retained with the nuclear matrix did not.

Animals↗
PubMed1987

Severe isolated tricuspid insufficiency in coronary artery disease.

We describe 3 patients who presented with severe cardiac disability as a result of tricuspid insufficiency, in the setting of severe coronary disease. Pertinent physical findings were signs of right heart failure, a tricuspid regurgitant murmur, and absence of left heart failure. Echocardiography and subsequent cardiac catheterization demonstrated significant tricuspid insufficiency, dilated right ventricle, impairment of right ventricular function, and preserved left ventricular function. Two patients were treated successfully with DeVega annuloplasty. Symptomatic tricuspid insufficiency can be seen in the setting of coronary artery disease and, when left ventricular function is well preserved, surgical correction is feasible.

Aged↗
PubMed1986

Macromolecular domains containing nuclear protein p107 and U-snRNP protein p28: further evidence for an in situ nuclear matrix.

Polyclonal antibodies have been produced which react with a nuclear protein having a molecular weight of 107kD and a pI of 8.7-8.8 (designated p107). This protein is shown to be a component of the residual ribonucleoprotein (RNP) network of the nuclear matrix. P107 localized exclusively to the nuclear interior but not within nucleolar or chromatin domains. We have taken advantage of this unique probe to examine whether the RNP network of the isolated nuclear matrix has a physical counterpart in situ. We show that RNA, p107, divalent cations and the 28 kD Sm antigen of U-snRNPs are components of in situ macromolecular assemblies. While the morphology and intranuclear distribution of these assemblies are insensitive to the removal of chromatin, they are markedly altered by degradation of RNA. Digestion in situ of RNA in the presence of EDTA followed by extraction with high ionic strength buffers solubilized the components of these assemblies. Electron microscopic and immunobiochemical data are presented which support the concept that the residual RNP network of the nuclear matrix is an isolate of a pre-existing structure, and that perturbations in this internal network can be created by RNA degradation, depletion of essential metal ions and proteolysis.

Animals↗
PubMed1986

Redistribution of U-snRNPs during mitosis.

In this study we examined the distribution of U-snRNPs during mitosis using a monoclonal antibody which recognizes the 28 kD protein associated with U-snRNP particles. During interphase U-snRNPs are concentrated within discrete intranuclear protein clusters. The onset of mitosis is accompanied by a breakdown of these nuclear protein clusters and U-snRNPs are redistributed between the condensing chromosomes. During metaphase and anaphase, two populations of U-snRNPs can be identified: those associated with the chromosome surface and a 'free' form distributed throughout the cytoplasm. During telophase, the reformation of nuclear protein clusters appears to be associated with the chromosome surface and coincides with chromatin decondensation. These studies suggest that the interphase assembly of nuclear domains containing U-snRNPs is sensitive to the transcriptionally active or decondensed state of chromatin.

Anaphase↗
PubMed1986

Comparison of angioplasty and bypass surgery in multivessel coronary artery disease.

The role of coronary angioplasty in the treatment of patient with multivessel coronary artery disease has not been fully established. We compared immediate and 1-year follow-up results in 60 patients undergoing coronary angioplasty for multivessel coronary disease in 1982 with 41 patients anatomically suitable for angioplasty but who underwent elective coronary bypass surgery during the same time period. Baseline variables were similar in both groups except for number of vessels diseased which was higher in the surgical group. Angioplasty was initially successful in 70% of cases. There were no deaths. Mean initial hospital days were lower in the angioplasty group. At follow-up there were no significant differences in survival, functional class, occurrence of subsequent myocardial infarction or use of cardiac medications. However, 33% of the successfully dilated patients required either repeat dilatation or subsequent bypass surgery because of restenosis or inadequate initial revascularization. The statistical power of the study was limited due to the small sample sizes. While demonstrating that angioplasty can be successfully performed in patients with multivessel disease, definitive conclusions about the comparability of the two treatments are hampered by possible selection bias and small patient numbers. This issue could be better addressed by a multicenter prospective randomized trial.

Adult↗
PubMed1986

Patent ductus arteriosus in patients more than 50 years old.

At the Mayo Clinic, from 1945 through 1983, a definitive diagnosis of patent ductus arteriosus was first made in 38 patients when they were more than 50 years old. Of the 29 patients who had cardiac catheterization, 14 had a small left-to-right shunt, 7 had a moderate shunt, and 8 had a large shunt. Five patients, including 2 with right-to-left shunts through the ductus, had pulmonary systolic pressures greater than 75 mm Hg. Thirty procedures were done in 29 patients: ductal ligation in 7, division and suture in 13, transaortic patch closure in 3, and closure via median sternotomy with extracorporeal circulation in 7. There was one intraoperative death (operative mortality, 3.3%). Although technically more challenging, surgical repair is associated with low mortality and excellent follow-up survival. The patients who benefit most from surgical correction are those with Qp/Qs greater than 1.5 and pulmonary artery systolic pressure less than 75 mm Hg.

Aged↗
PubMed1986

Angioplasty for aortocoronary bypass graft stenosis.

During the period November 1979 to October 1984, 19 patients at our institution underwent balloon angioplasty of partial or complete obstruction of aortocoronary artery saphenous vein bypass grafts. The procedures were performed a mean of 38 months after a coronary bypass operation to relieve recurrent angina of at least class 2 in the Canadian Cardiovascular Association functional classification. Graft angioplasty was successful in 16 of the 19 patients, and the location of the lesion (in the origin, body, or distal insertion of the graft) did not seem to be an important factor in achieving a successful result. At a mean follow-up interval of 20 months (range, 1 to 40 months), 14 patients had symptomatic improvement. Two patients required late repeat operation and four had repeat angioplasty because of restenosis. Our experience supports the use of balloon angioplasty in selected patients with bypass graft stenosis, but restenosis remains a substantial problem.

Adult↗