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Biomedical subjects

J J Collins

Publications and source records attributed to J J Collins.

At least 217 records · Page 12Linked to original sources
PubMed1986

Comparison of dopamine and dobutamine in patients requiring postoperative circulatory support.

We compared dopamine and dobutamine following cardiac surgery in a sequential cross-over study of 9 patients who required inotropic support after volume replenishment. Seven patients had mitral valve replacement, 2 with simultaneous coronary revascularization (CABG), and 1 each with simultaneous tricuspid annuloplasty and aortic valve replacement; 1 had isolated CABG and 1 had repair of a postinfarction ventricular septal defect. Heart rate, right and left atrial pressures, pulmonary and mean arterial pressure, systemic and pulmonary vascular resistance, and cardiac index were measured and calculated. Inotropic support with dopamine or dobutamine was begun for treatment of low cardiac index within 12 hours postoperatively. Measurements were made after 20 minutes on either agent at 5-10 micrograms/kg per min when cardiac output and general clinical state were stable. Each patient was then switched to the other agent at approximately the same dose rate, titrating the dosage to the same cardiac output, and repeat measurements were made at 20 minutes when again stable. Similar dosages of dopamine (6.2 +/- 1.7 micrograms/kg/min) and dobutamine (6.7 +/- 2.5 micrograms/kg/min) produced equivalent heart rate (103 +/- 19 vs. 102 +/- 13 beats/min, p = NS), cardiac index (2.8 +/- 1.1 vs. 2.9 +/- 1.2 l/min/m2, p = NS), and pulmonary arterial pressure and vascular resistance. Mean systemic arterial pressure was significantly lower with dobutamine (59 +/- 5 vs. 67 +/- 7 mmHg, p less than 0.05) as were mean left (14 +/- 5 vs. 18 +/- 6 mmHg, p less than 0.0001) and right (9 +/- 2 vs. 11 +/- 2 mmHg, p less than 0.05) arterial pressures.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1986

Pacemaker backup-mode reversion and injury during cardiac surgery.

Both electrocautery and internal defibrillation are routinely used in cardiac operations. The cases of 5 patients are presented in whom backup-mode reversion or injury of permanently implanted pulse generators occurred during a cardiac procedure. The theoretical explanations for backup-mode reversion and generator or tissue injury are discussed, and recommendations are made for the management of patients with a pacemaker who are to undergo a cardiac operation.

Aged↗
PubMed1986

Clinical response to coronary artery reoperations.

Repeat coronary artery bypass operations were performed on 112 patients at a university hospital between 1971 and 1981. When compared with patients who did poorly after a first operation but did not have repeat surgery, patients undergoing repeat surgery tended to be younger, to have a higher smoking rate and to have fewer prior myocardial infarctions, fewer diseased vessels and fewer lesions in distal vessels. At least 1 graft was occluded in 83% of patients undergoing reoperation, and a mean of 1.7 grafts were placed at reoperation. The operative mortality rate was 4%, with a follow-up mortality rate of 6% at a mean of 3.8 years. After reoperation, patients initially showed improvement to a mean specific activity scale class of 1.6, compared with 2.4 before the first operation and 2.7 before the second operation. The principal correlate of a better long-term symptomatic response compared with that in the period before the first operation was a lower serum cholesterol level, whereas the principal correlate of a better symptomatic response compared with that in the period just before the reoperation was the left ventricular ejection fraction. As recurrent symptoms after a first coronary artery operation become more prevalent, consideration of the selection factors and prognostic correlates of reoperation will become increasingly important.

Coronary Angiography↗
PubMed1986

Posttranscriptional control of Klebsiella pneumoniae nif mRNA stability by the nifL product.

Posttranscriptional control of nif mRNA stability was demonstrated by functional and chemical analyses, using specific probes for four nif transcripts. In the wild type, nif transcripts (except nifLA) were stable during derepression, with half-lives of approximately 30 min. They were dramatically destabilized by O2 or elevated temperature (41 degrees C) and to a lesser extent by NH4+. In contrast, the nifLA message was not particularly stable, and posttranscriptional control was not evident. In NifL- strains, both forms of analysis indicated that the nifL product was involved in nif mRNA destabilization in the presence of O2 and NH4+.

Acetates↗
PubMed1986

Femorofemoral bypass to relieve acute leg ischemia during intra-aortic balloon pump cardiac support.

This study reports our experience with 10 patients who underwent the emergent construction of a femorofemoral bypass graft to salvage an acutely ischemic lower extremity following the insertion of a transfemoral intra-aortic balloon pump catheter. All patients had excellent resolution of the ischemia and salvage of the extremity. Half of the procedures were done at the bedside with the remainder performed in the operating room. No long-term infections or ischemic sequelae resulted from the procedures in the nine patients available for long-term follow-up. The use of femorofemoral bypass grafting is, therefore, recommended in patients with severe ipsilateral limb ischemia who are dependent on an intra-aortic balloon pump to prevent extremity tissue loss as well as the systemic metabolic manifestations of ongoing tissue ischemia and necrosis. Patient selection, technical considerations, and postoperative management are discussed.

Adult↗
PubMed1985

Long-term results of open mitral valve reconstruction for mitral stenosis.

Open mitral reconstruction for rheumatic mitral stenosis (MS) was performed in 120 patients, 101 women and 19 men, aged 22 to 75 years (mean 49). Nine patients were functional class II, 106 class III, 5 class IV; 13 only underwent noninvasive studies, including echocardiography, before surgery, while 107 had preoperative cardiac catheterization studies. The latter showed a mean valve area of 1.09 cm2 and a pulmonary artery wedge to left ventricular mean diastolic gradient of 14 mm Hg. Cardiopulmonary bypass was used in all patients for open reconstruction under direct vision. Superior commissurotomy was done in 115 patients, inferior in 114, papillary muscles were incised and chordae lengthened in 39 and calcium was excised from valve leaflets in 23. Suture or ring anuloplasty was not required in any patient. The series was begun January 1972 and terminated in January 1984. Personal follow up was conducted in July 1984. There were no operative deaths in the 120 patients. There were 5 late deaths, all from noncardiac causes. The mean follow-up time was 53 months. The actuarial probability of survival at 10 years was 95 +/- 2%. Thromboemboli occurred in 9 patients; the probability of freedom from thromboemboli at 10 years was 91 +/- 3% and the linearized rate was 1.8%/patient-year of follow-up. Reoperation was required in 9 patients, an absolute incidence of 7.5% and an annual incidence of 1.7%/patient year. At 10 years the probability of freedom from reoperation was 84 +/- 5%.

Actuarial Analysis↗
PubMed1985

Balloon pump support of the failing right heart.

This report reviews a clinical experience with pulmonary artery counterpulsation with a balloon pump in a patient with pulmonary embolization superimposed upon severe trivalvular rheumatic heart disease. This patient underwent a pulmonary embolectomy and triple-valve replacement requiring a pulmonary artery balloon pump for bypass discontinuation and postbypass hemodynamic support. The field of right heart counterpulsation is briefly reviewed, and the technical details of the implantation and management of the device are elaborated.

Cardiomegaly↗
PubMed1985

Coronary artery disease in patients requiring abdominal aortic aneurysm repair. Selective use of a combined operation.

The chief cause of operative mortality after abdominal aortic aneurysm (AAA) repair is myocardial infarction. For this reason, routine coronary angiography followed by prophylactic coronary artery bypass grafting (CABG) prior to AAA repair has been recommended by some surgeons. We report here the results of the selective use of a combined operation. Two hundred twenty-seven patients had elective or emergency repair of nonruptured AAA on our service from 1972 to 1983. Prior to surgery, all patients underwent careful clinical evaluation for the presence of coronary artery disease (CAD) and were classified into the following: group I (n = 121), no clinical evidence of CAD, 53%; group II (n = 96), clinical evidence of stable CAD, symptomatic or asymptomatic, 42%; group III (n = 10), unstable CAD, five per cent; Group IIIa (n = 4), asymptomatic AAA; and group IIIb (n = 6), symptomatic AAA. Seven patients ultimately assigned to group II underwent stress electrocardiogram (ECG) and eight group II patients had coronary angiography before surgery. All patients in groups I and II underwent elective or urgent repair of their AAA without CABG. Prior to surgery, these patients were managed with placement of a pulmonary artery catheter and incremental volume loading to construct a left ventricular performance curve as a guide to surgical fluid replacement. All were carefully monitored for at least 48 hours after surgery in an intensive care unit. Four patients (group IIIa) with unstable CAD and asymptomatic AAA underwent CABG followed by elective AAA repair within six months. Six patients (group IIIb) with unstable CAD and symptomatic AAA underwent combined open heart surgery (CABG and, in one patient, valve replacement) and AAA repair as a single operation. There was no operative mortality in group III patients. Thirty-day operative mortality for the entire group of 227 patients was 1.3% (three deaths), with only one death from a myocardial infarction (0.4%). While there is clearly a high incidence of CAD in patients with AAA, the present results indicate that these individuals can be managed with low risk by a selective approach based upon clinical assessment of their CAD. Our experience further demonstrates that patients with unstable CAD and symptomatic AAA may have both lesions safely repaired as a single operative procedure.

Adult↗
PubMed1985

Control of Klebsiella pneumoniae nif mRNA synthesis.

Four probes, each specific for a single nif transcript, were used for an analysis of the regulation of nif mRNA synthesis. Transcription of the nifLA operon was repressed by NH4+ but not by amino acids, O2, or temperatures above 37 degrees C. The nifA gene product was required for the activation of transcription of the other nif operons but not nifLA. Synthesis of the other nif transcripts was rapidly turned off by the addition of O2, NH4+, serine, or glutamine. These regulatory effects required the nifL product. However, the nifL product was not required for the cessation of synthesis of these transcripts at elevated temperatures.

Gene Expression Regulation↗
PubMed1985

Surgical management of carcinoid heart disease.

Two female patients with carcinoid heart disease, ages 56 and 32 years, underwent pulmonic valve resection surgery and tricuspid valve replacement with a porcine bioprosthesis. Preoperatively, both patients were in function class 4 with severe right-side congestive failure and signs of tricuspid regurgitation and pulmonic stenosis. Both underwent surgery for porcine tricuspid valve replacement (33 and 31 mm valves) and pulmonic valve resection. Postoperatively, both patients had only minimal symptoms, including trace ankle edema and soft pulmonic murmurs, despite persistence of the systemic symptoms of carcinoid syndrome. Pre- and postoperative catheterization data documented hemodynamic improvements. One patient eventually died of hepatic failure due to metastatic disease. At autopsy, her bioprosthesis was free of carcinoid valvular changes.

Adult↗
PubMed1985

Aggressive surgical management of post-infarction angina: results of myocardial revascularization early after transmural infarction.

In our Division of Cardiothoracic Surgery between 1970 and 1982, 110 patients (88 males and 22 females) had coronary artery bypass grafts (CABG) performed for unstable angina pectoris after acute transmural myocardial infarction. Fifty-one patients (mean age 59 years) had CABG within 2 weeks of myocardial infarction (Group 1); and 59 patients (mean age 56 years) (p = NS) within 6 weeks of myocardial infarction (Group 2). The incidence of preoperative arrhythmias, left ventricular ejection fraction, end-diastolic pressure, and the number of vessels diseased were similar in Groups 1 and 2. The incidence of cardiogenic shock was higher in Group 1 (16/51, 31% vs 2/59, 3% [p < 0.001]). This was also the case with the use of the intraaortic balloon (32/51, 63% vs 12/59, 20% [p < 0.001]), and the need for emergency operation (29/51, 57% vs 4/59, 7% [p < 0.001]). The mean number of grafts was 2.8 in Group 1 and 3.0 in Group 2 (p = NS). Operative mortality was 20% (10/51) in Group 1 and 7% (4/59) in Group 2 (p < 0.01). Excluding patients in cardiogenic shock, operative mortality was 0% (0/35) in Group 1 and 5% (3/57) in Group 2 (p = NS). Incidences of late death, recurrent angina, and permanent disability were similar during mean follow-up times of 3.2 years in Group 1 and 4.1 years in Group 2. Actuarial probability of survival was 96% at 1 year and 83% at 5 years. Myocardial revascularization early after transmural myocardial infarction has a low risk, especially in the absence of cardiogenic shock. These results justify an aggressive approach to unstable angina, including patients within 2 weeks of transmural infarction.

Journal Article↗
PubMed1985

Early and late risk of mitral valve replacement. A 12 year concomitant comparison of the porcine bioprosthetic and prosthetic disc mitral valves.

A consecutive series of 706 mitral valve replacements was performed from January, 1972, to January, 1984. The follow-up ranged from 6 to 150 months with a mean of 50 and a median of 43 months. Seven percent (50) of the patient were lost to follow-up. There were 243 men and 463 women, whose ages ranged from 17 to 86 years (mean 58). A porcine bioprosthetic valve was implanted in 528 patients (514 Hancock and 14 Carpentier-Edwards valves) and a prosthetic disc valve in 178 patients (102 standard disc Björk-Shiley, 34 Beall, and 42 Harken disc valves). Seven patients were in Functional Class II, 325 in Class III, and 374 in Class IV. A concomitant operative procedure was performed in 253 of the 706 patients (36%). Mitral regurgitation was the primary hemodynamic lesion in 363 and mitral stenosis in 343. Operative mortality figures were as follows: 77 of 706 (11%) for the overall group, 34 of 453 (7.5%) for isolated mitral valve replacement, 30 of 169 (17.5%, p = 0.001) for mitral replacement plus coronary bypass, 49 of 528 (9%) for the bioprosthetic valve group, and 28 of 178 (16%) for the prosthetic disc valve group (p = 0.01). After the operation, 262 patients were in Functional Class I, 99 in Class II, and 18 in Class III. The long-term survival rate was significantly lower in patients who had an associated procedure (45% +/- 6%), who had mitral regurgitation rather than mitral stenosis (53% +/- 5% versus 67% +/- 4%) (p = 0.002), who were in Functional Class IV rather than Classes I to III (51% +/- 4% versus 70% +/- 4%) (p = 0.001), and who received a prosthetic disc valve rather than a bioprosthesis (40% +/- 6% versus 67% +/- 4%) (p = 0.001). Thromboembolic rates were significantly higher with prosthetic valves than with bioprosthetic valves (4.6% +/- 0.22% versus 2.4% +/- 0.5% per patient-year of follow-up), and the incidence of anticoagulant-related hemorrhage was significantly higher in the prosthetic valve group (1.65% versus 0.43% per patient-year). Primary valve dysfunction was significantly more common in the bioprostheses (1.23% versus 0.40% per patient-year).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Immunotherapy of murine leukemia. XI. differential susceptibility of spleen cells from serum-protected mice to the in vitro immunosuppressive effects of Friend leukemia virus-infected splenocytes.

It has previously been shown that DBA/2 mice protected against the development of Friend leukemia virus (FLV)4-induced disease by the passive administration of heterologous antisera directed against disrupted virions or the major viral envelope glycoprotein (gp71) fail to undergo the generalized immunosuppression which characterizes FLV leukemogenesis. In the present studies, the susceptibility of spleen cells from serum-protected mice to the immunosuppressive effects of FLV-infected spleen cells has been examined by means of in vitro assays of antibody production and of natural killing (NK). In contrast to the parallel suppression of both functions in FLV-infected mice and their lack of suppression in serum-protected animals, a dichotomy was observed in the in vitro susceptibility of these activities of spleen cells from serum-protected mice to the suppressive effects of virus-infected splenocytes, implying that more than one mechanism of suppression is operative. Thus, the antibody-producing capability of serum-protected splenocytes was not suppressed by FLV-infected spleen cells, this suppression reflecting the activity of infectious virus, while the NK effector function of serum-protected spleen cells was as susceptible as that of normal splenocytes to suppression by virus-infected spleen cells. This suppression of NK activity is mediated by virus-induced suppressor cells and does not involve free infectious virus, in contrast to suppression of antibody production. These results thus indicate that, while serum therapy inhibits the development of the virus-induced NK suppressor cells found in the spleens of progressively infected mice, splenic NK effectors, which are present, demonstrate full susceptibility to the suppressive effects of such independently generated virus-induced suppressor cells. Preliminary attempts at characterizing these NK suppressors in the spleens of FLV-infected mice indicate that they are not eliminated by treatment with antisera directed against T cells, B cells, macrophages or FLV gp71. However, Percoll fractionation of spleen cells from infected mice has revealed the presence of an expanded (as compared to normal spleen cells) population of cells of density 1.077 which demonstrates high in vitro NK suppressor activity, presumably representing the virus-induced suppressor cells measured in this assay. At the present time, the mechanism of the resistance of serum-protected spleen cells' antibody production to suppression by FLV-infected splenocytes (i.e., by FLV itself) remains undefined.

Animals↗
PubMed1984

Disadvantages of prostacyclin infusion during cardiopulmonary bypass: a double-blind study of 50 patients having coronary revascularization.

Prostacyclin (PGI2) has been suggested for use in cardiopulmonary bypass (CPB) because of its positive effects on platelet number and function. Fifty patients who underwent coronary artery bypass grafting using a bubble oxygenator received heparin, 3 mg per kilogram of body weight, and then were randomly assigned to receive PGI2, 25 ng/kg/min, beginning 5 minutes before and until the end of CPB (26 patients) or a placebo (24 patients). Both groups were similar in sex, age, heparin dose, protamine dose, and CPB time. During CPB, mean arterial pressure fell significantly with PGI2 (76 +/- 2 mm Hg to 53 +/- 2 mm Hg; p less than 0.05) and necessitated pressor substances. Platelet counts fell significantly in both groups with the start of CPB, but after 60 minutes were similar in both groups (118 +/- 9 X 10(3) versus 130 +/- 8 X 10(3); not significant [NS]) and were unchanged 3 hours after CPB. Total chest tube output was 647 +/- 51 ml (placebo group) versus 576 +/- 34 ml (PGI2 group) (NS); 18 of the patients given PGI2 required 26 transfusions compared with 16 transfusions in 8 of the patients given a placebo (p less than 0.05). In PGI2 patients, arterial oxygen tension on 100% oxygen fell from 281 +/- 18 mm Hg before CPB to 223 +/- 17 mm Hg immediately after CPB (p less than 0.05). The placebo patients did not show a change in this variable.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗