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Biomedical subjects

R M King

Publications and source records attributed to R M King.

At least 37 records · Page 2Linked to original sources
PubMed1987

Repair of ascending aortic dissection. Influence of associated aortic valve insufficiency on early and late results.

Operative treatment of dissections of the ascending aorta differs from that for the descending aorta, not only because of the need for cardiopulmonary bypass, but also because of the frequent occurrence of aortic valve insufficiency. To determine the early and late results of operative repair, we have reviewed the case histories of 121 consecutive patients who underwent repair of ascending aortic dissections between 1962 and 1985. Ages ranged from 16 to 79 years (mean 56 +/- 14 years); 54 patients had operation within 2 weeks of onset of symptoms (acute), and the remainder had later repair (chronic). Seventy patients (58%) had clinical evidence of aortic insufficiency at the time of admission. During repair of acute dissection, 10 patients (19%) had aortic valve resuspension and 15 patients (28%) had aortic valve replacement. During repair of chronic dissection, eight patients (12%) had resuspension and 43 patients (64%) had replacement. Overall operative mortality was 22%, significantly higher for patients with acute than for those with chronic dissections (39% versus 9%, p less than 0.01). Operative risk was similar for patients who underwent repair of ascending aortic dissections without valve resuspension or replacement (31%) versus those who had repair with aortic valve resuspension (17%) or replacement (17%). During a follow-up period ranging from 1 to 208 months, aortic regurgitation developed in only two patients who did not have aortic insufficiency at the time of repair. Late aortic regurgitation necessitating reoperation developed in one of the 15 survivors who had aortic valve resuspension. Eight patients undergoing aortic valve replacement had complications of their prostheses, including one periprosthetic leak and four mechanical failures. We conclude that resuspension or replacement of the aortic valve does not increase the risk of repair of ascending aortic dissections. Selective management of aortic insufficiency (with valve repair whenever possible) yields satisfactory long-term results.

Aortic Dissection↗
PubMed1986

Mechanical decalcification of the aortic valve.

Thromboembolism and anticoagulant-related complications secondary to prosthetic aortic valve replacement constitute a significant risk (28% at 5 years). From 1978 through 1984, decalcification of the aortic valve was performed in 8 patients who were undergoing coronary artery revascularization. Preoperative gradients of between 30 and 80 mm Hg (mean, 50 mm Hg) were abolished after operation. To determine the viability of decalcification, the records of 84 additional patients who had undergone this procedure between 1959 and 1978 were reviewed (86% before 1965). There were 60 male and 32 female patients ranging from 14 to 74 years old (mean, 49 years). The cause of the calcification was a bicuspid valve in 32 patients (35%), senile calcification in 9 (10%), and rheumatic fever in 50 (54%); the cause in 1 patient was unknown. Thirty-day mortality was 13%. Follow-up was 98% complete and ranged from 6 months to 22 years (mean, 7 years). Aortic valve replacement was subsequently required in 25 patients. Freedom from reoperation at 1, 5, 10, and 15 years was 98%, 75%, 43%, and 26%, respectively, for patients with rheumatic valves compared with 97%, 76%, 57%, and 51%, respectively, for those with bicuspid valves. Survival for patients with rheumatic valves at 1, 5, 10, 15, and 20 years was 93%, 70%, 48%, 40%, and 35%, respectively, compared with 100%, 66%, 57%, 46%, and 46% for patients with bicuspid valves. At follow-up, 61% of the patients were in New York Heart Association Functional Class I or II. Causes of late death were valve related (30%), congestive heart failure (27%), and myocardial infarction (24%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Primary chest wall tumors: factors affecting survival.

Between 1955 and 1975, chest wall resection was done in 90 patients for primary chest wall tumors. Ages ranged from 8 to 96 years (mean, 44.3 years). A painful mass was the most common sign and symptom. Eighty-two tumors (91.1%) were located in the lateral chest wall and eight, in the anterior thorax. The tumor was malignant in 71 patients (78.9%) and benign in 19. All patients with benign tumors had complete excision and are currently free from disease. Malignant fibrous histiocytoma, chondrosarcoma, and rhabdomyosarcoma constituted 62% of the malignant neoplasms. Most malignancies were treated by wide resection. There were no thirty-day operative deaths. Overall 1-, 5-, and 10-year survival was 89%, 57%, and 49%, respectively. Recurrent tumor developed in 37 patients (52%); 5-year survival, however, was only 17% after recurrence. Cell type and extent of invasion significantly influenced survival. Both chondrosarcoma and rhabdomyosarcoma had a better prognosis than malignant fibrous histiocytoma (p less than 0.05). We conclude that early resection is the treatment of choice for primary malignant chest wall tumors and that development of recurrent disease is an ominous event.

Adolescent↗
PubMed1986

Early and late results following repair of dissections of the descending thoracic aorta.

Management of dissections of the descending thoracic aorta remains controversial, especially with regard to timing and method of repair. To clarify these and other issues we have reviewed our total experience with repair of descending aortic dissections between 1962 and 1983. The 44 men and 20 women had a mean (+/- SEM) age of 59 +/- 2 years (range, 19 to 83 years), and in all patients the dissection originated in and was limited to the aorta distal to the left carotid artery (Stanford type B, DeBakey types IIIa and IIIb). Twenty-nine patients underwent operation within 2 weeks of the onset of symptoms (acute), and the remainder had later repair (chronic). During repair, circulation distal to the aortic cross-clamp was supported with cardiopulmonary bypass or shunt in two thirds of patients. Overall, 18 deaths occurred less than or equal to 30 days postoperatively (operative risk 28%), and risk was higher in acute (45%) than in chronic (14%) dissections. Operative risk was not significantly related to protection of the distal circulation. The most serious postoperative complication was spinal cord ischemia manifested by paraplegia in five patients (8%) and transient or permanent paraparesis in six patients (9%). Risk of spinal cord ischemia was significantly lower in patients who had protection of the distal circulation during operative repair (8% vs. 44%, p = 0.003). Late survival, including hospital deaths, was 49% +/- 7% at 5 years after operation; 22 of the 46 patients who survived repair were found to have aneurysms involving the thoracic and/or abdominal segments of the aorta. Our results indicate that repair of chronic dissection of the thoracic aorta has a lower operative risk than repair of acute dissections, and initial medical management of acute dissection may be indicated if no early complications occur. Risk of spinal cord ischemia is significantly reduced by cardiopulmonary bypass or shunt and is preferred over aortic cross-clamping alone. Finally, these patients require careful long-term follow-up because of the high incidence of residual or recurrent aortic aneurysms.

Acute Disease↗
PubMed1986

Concomitant mitral valve repair or replacement and coronary revascularization.

Patients undergoing combined mitral valve replacement and coronary revascularization require surgical skill and especially judgment for optimal results. In our hands, cardioplegia has not been a pivotal event in affecting survival, and this probably relates to our previous philosophy of limiting the hypothermic ischemic episodes to 15-minute intervals. Currently, we believe that valve repair, when it can be accomplished, is preferable to valve replacement, especially in the patient with ischemic mitral valve disease. When repair cannot be satisfactorily accomplished, replacement with retention of the posterior leaflet seems clinically to be associated with less disturbance of left ventricular function.

Anesthesia↗
PubMed1986

Prognostic factors and surgical treatment of partial atrioventricular canal.

In this study we sought to determine the prognostic factors that influence early and late survival after repair of partial atrioventricular canal and the need for reoperation. From January 1962 to January 1984, 199 patients underwent correction of partial atrioventricular canal. There were 73 male and 126 female patients, ranging in age from 5 months to 71 years (mean 11.2 years). Total 30 day operative mortality was 5.5%. Since 1980, the mortality has declined to 3%. Significant determinants of operative mortality were congestive heart failure, cyanosis, failure to thrive, age less than 4 years, and moderate-to-severe mitral valve insufficiency (p less than .01). Sex, cardiomegaly, radiographically increased pulmonary vasculature, intraoperative postrepair right ventricular-to-left ventricular pressure ratio, and pulmonary-to-systemic flow ratio were not significant in determining early mortality. Follow-up ranged from 1 to 21.4 years (mean 15.2). There were seven late deaths, primarily in older patients from atherosclerotic disease or malignancy. Late survival was 98% at 1 year and 96% at 20 years. Reoperation was performed on 18 patients, 15 for mitral incompetence, and three for subaortic stenosis. The need for reoperation correlated with severity of postrepair mitral insufficiency. Longterm survival is excellent after repair of the partial form of atrioventricular canal.

Aged↗
PubMed1985

Surgical palliation of respiratory insufficiency secondary to massive exuberant polyostotic fibrous dysplasia of the ribs.

A middle-aged man with long-standing polyostotic fibrous dysplasia had severe progressive restrictive lung disease with hypoxemia and pulmonary hypertension with heart failure because of exuberant intrathoracic, extraosseous proliferation of dysplastic tissue. Subtotal resection of this benign tissue mass ameliorated the respiratory insufficiency and led to sustained improvement in exercise tolerance, increase in pulmonary reserve, and decrease in signs of heart failure and pulmonary hypertension.

Fibrous Dysplasia of Bone↗
PubMed1985

Enterobacter mediastinitis following cardiac surgery.

Eight cases of sternal/mediastinal infection due to Enterobacter species were seen in postoperative cardiac patients during 1980 to 1981. The attack rate was 14.5% (8/55), compared to 3.7% (2/54) for an identical period in 1979 to 1980 (p less than 0.05). Cases varied in severity from fulminant, acute bacteremic infections (one death) to less severe wound infection. Late complications or recurrences were not seen. There was a hospital-wide increase, relative to all other gram-negative bacillary isolates, in Enterobacter laboratory isolations, but no increased rate of infection in any other specific surgical condition. No personnel, materials, or techniques were associated with the outbreak, and all but two environmental cultures were negative. Case-control analysis suggested that surgical complications and prophylactic cephalosporins were associated with infection. Prospectively, an additional 85 cardiac surgery patients had increased Enterobacter skin/wound colonization following perioperative prophylaxis with cephalosporin antibiotics. After introduction of barrier isolation and restriction of contacts no further mediastinitis occurred in 100 subsequent cardiac surgery patients. This study indicates that Enterobacter may be major pathogens causing post-cardiac-surgery infection not prevented by cephalosporin prophylaxis.

Cardiac Surgical Procedures↗
PubMed1985

Carcinoma of the breast associated with pregnancy.

Sixty-three pregnant patients were treated for primary carcinoma of the breast at the Mayo Clinic between 1950 and 1980. These patients had a greater incidence of nodal metastasis and scirrhous histopathologic factors than did non-pregnant patients with a malignant condition of the breast. The five year survival rate of pregnant patients with localized malignant growths of the breast was 80 per cent. Improved survival time was not demonstrated for patients who terminated the pregnancy.

Abortion, Therapeutic↗
PubMed1984

Multidrug-resistant Serratia marcescens bacteriuria related to urologic instrumentation.

An outbreak of urinary tract infections caused by multidrug-resistant Serratia marcescens lasted for 12 months and was found to be related to urologic instrumentation. Thirty-four patients had primary infections; four had cross-infections. Only six patients had indwelling bladder catheters. The median interval between instrumentation and initial isolation of Serratia was six days. Seventy-three percent of patients were symptomatic, two were bacteremic. No common instruments, personnel, or wards were identified, and environmental cultures failed to reveal the epidemic strain of Serratia. The outbreak ended when the instrument disinfectant was changed. Serotyping was identical in nine of ten isolates. Intraspecies conjugation demonstrated resistance transfer of gentamicin, tobramycin, carbenicillin, chloramphenicol, and co-trimoxazole. The enzyme 6'-N-acetyl transferase was responsible for gentamicin-inactivation in patient isolates and a transconjugate. Although no significant spread of this multidrug-resistance plasmid to other Enterobacteriaceae occurred in the hospital, two instances of apparent in vivo transfer to other bladder organisms occurred.

Adult↗
PubMed1984

The reaction of the anti-interferon-alpha monoclonal antibody, NK2, with different interferons.

Analysis of the neutralization of human interferon-alpha by the monoclonal antibody NK2 showed, by three different methods, that the avidity constant was about 10(10)M-1. A small decrease in the avidity constant (and in the antibody titre) with increasing interferon concentrations was observed, suggesting that the antibody-interferon complex had a little biological activity. The antibody neutralizes the interferon by preventing the binding of interferon to susceptible cells. It does not react with human-gamma, mouse-alpha, monkey, bovine or rabbit interferons.

Antibodies, Monoclonal↗
PubMed1984

Lack of retrovirus gene expression in somatic cell hybrids of friend cells and teratocarcinoma cells with a teratocarcinoma phenotype.

Two types of hybrids between cells with erythroid phenotype (Friend cells) and teratocarcinoma cells can be distinguished: cell hybrids with an erythroid phenotype, which release or can be induced to release large amounts of Friend spleen focus-forming virus (F-SFFV) on exposure to bromodeoxyuridine and cell hybrids with a teratocarcinoma phenotype, which do not release Friend virus and are not inducible for F-SFFV release. In this paper, we attempted to relate these differences to the expression of F-SFFV and Friend murine leukemia virus (F-MuLV) functions. Teratocarcinoma phenotype hybrids retained F-SFFV-and F-MuLV-related provirus sequences. They did not express F-SFFV- or F-MuLV-related RNA or proteins. The hybrids differentiated to endoderm-like cells on exposure to retinoic acid or hexamethylene-bis -acetamide. These cells, in contrast to the teratocarcinoma phenotype (uninduced) cells expressing SSEA-1-like antigens, did not express SSEA-1-like antigens; they formed typical, prekeratin-staining cytoskeletal structures and could be induced to release mouse interferon. The differentiating cells, but not the uninduced teratocarcinoma hybrids, were infected productively with F-MuLV or the F-MuLV--F-SFFV complex. They, however, did not express endogenous F-SFFV. Endogenous F-SFFV functions could not be rescued by infection with F-MuLV. Induction of teratocarcinoma hybrids with retinoic acid did not activate endogenous F-MuLV or F-SFFV transcription or protein synthesis. These data demonstrated two control mechanisms of Friend virus repression: one which acted trans during formation of the cell hybrids and was maintained only in teratocarcinoma phenotype cells and the other which acted cis and was still operative during induction of endodermal differentiation.

Animals↗
PubMed1984

Surgery for tricuspid regurgitation late after mitral valve replacement.

Tricuspid valve insufficiency may contribute to a poor hemodynamic result after mitral valve replacement. To determine the role of surgical treatment, we have reviewed the records of 32 adult patients who underwent tricuspid valve repair or replacement 4 months to 14 years after mitral valve replacement. Mild tricuspid valve insufficiency at the time of mitral valve replacement was present in 21 patients (66%); 26 patients (81%) had New York Heart Association class IV disability. Tricuspid annuloplasty was performed in 16 patients, and the remainder received various prosthetic valves. Concomitant repair of mitral valve periprosthetic leak and/or replacement of the aortic valve was necessary in 18 patients (53%). Hospital mortality was 25%, and all early deaths were related to low cardiac output. Among hospital survivors there have been 14 late deaths for 3 and 5 year actuarial survival rates of 65% and 44%. Twelve of the 14 patients who died late and one of 10 patients who were alive at the end of the follow-up period had little or no functional improvement after tricuspid valve repair or replacement. The high early and late mortality and poor functional outcome for patients undergoing tricuspid valve surgery late after mitral valve replacement contrast with our good overall results in reoperation for prosthetic heart valves. It appears that serious tricuspid valve insufficiency after mitral valve replacement frequently signals right ventricular failure and dilatation; restoring valve competence is palliative. This experience encourages us to continue our policy of liberal indications for tricuspid valve annuloplasty at initial mitral valve replacement.

Adult↗
PubMed1983

Expression in Saccharomyces cerevisiae of human interferon-alpha directed by the TRP1 5' region.

The complete 5' flanking region of the yeast TRP1 gene encoding N-(5'-phosphoribosyl)- anthranilate isomerase, a nonabundant protein, has been cloned and the nucleotide sequence data has been extended from -102 to -440. The CT block--CAAG structure common to all efficiently expressed yeast genes is altered in the 5' region of TRP1 and a sequence postulated to be involved in general amino acid regulation is absent. There are two possible TATA boxes at -224 and -262. TRP1, in common with HIS3, HIS4 and TRP5 has a region of dyad symmetry upstream of the coding sequence which may play a role in initiation of transcription. The relative efficiency of gene expression directed by the complete 5' TRP1 region was assessed by comparison with that of PGK by inserting a cDNA for a human interferon-alpha downstream of their respective 5' regions. The respective interferon yields indicate that their in vivo expression capabilities are a function of their 5' regions.

Aldose-Ketose Isomerases↗
PubMed1983

Characterization and properties of a modified human interferon-alpha containing an additional 18 amino acids at the N-terminus.

A modified human interferon-alpha 2 was produced in Escherichia coli cells infected with phage M13 mp7 containing an interferon-alpha gene. After purification by immunochromatography with the monoclonal antibody NK2, the N-terminal amino acid sequence was determined. The N-terminal methionine was absent but an additional sequence of 18 amino acids at the N-terminus was retained. The modified interferon-alpha 2 was indistinguishable from authentic interferon-alpha 2 in its ability to activate natural killer cells, to slow the growth of Daudi cells, and to confer virus resistance on heterologous cells.

Amino Acid Sequence↗