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Biomedical subjects

H K Pilegaard

Publications and source records attributed to H K Pilegaard.

35 records · Page 2Linked to original sources
PubMed1992

Calcium utilization coupled to stimulation of postjunctional alpha-1 and alpha-2 adrenoceptors in isolated human resistance arteries.

Human s.c. resistance arteries (internal diameters 158-353 microns) were mounted in a microvascular myograph, and experiments were designed to examine the calcium pools utilized by selective stimulation of alpha-1 and alpha-2 adrenoceptors. In a concentration-dependent manner, phenylephrine and B-HT 933 evoked contractions mediated by alpha-1 and alpha-2 adrenoceptors, respectively, both in calcium-containing and in calcium-free saline. With respect to the maximum response to potassium in calcium-containing saline, the maximum responses to phenylephrine and B-HT 933 were 96 +/- 6 and 85 +/- 8%, respectively, in calcium-containing saline, and 79 +/- 4 and 14 +/- 2%, respectively, in calcium-free saline. A qualitatively similar difference in maximum responses to alpha-1 vs. alpha-2 adrenoceptor stimulation in calcium-free saline was demonstrated for norepinephrine in the presence of antagonists selective for the two alpha adrenoceptor subtypes. The maximum relaxation in calcium-containing saline produced by the calcium antagonist nitrendipine was 52 +/- 3% in vessels precontracted with phenylephrine, but 80 +/- 5% in vessels precontracted with B-HT 933. A quantitative difference in receptor reserves was demonstrated between alpha-1 and alpha-2 adrenoceptors; 90% of the maximum response was obtained at 34 +/- 5 and 57 +/- 8% receptor occupation, respectively. These data suggest that compared to responses mediated by stimulation of postjunctional alpha-1 adrenoceptors, stimulation of postjunctional alpha-2 adrenoceptors relies heavily on calcium influx. Stimulation of postjunctional alpha-2 adrenoceptors is, however, also coupled to intracellular release of calcium in isolated human s.c. resistance arteries.

Adrenergic alpha-Antagonists↗
PubMed1991

[Hemithyroidectomy. A consecutive series of 100 patients].

Treatment of isolated, scintigraphically cold thyroid nodules in the thyroid gland by means of hemithyroidectomy ensures that, in patients with thyroid carcinoma, it is possible subsequently to carry out total thyroidectomy by means of an intervention limited to the contralateral surgically intact side. The object of the present investigation to assess whether this therapeutic strategy was rational and safe. Hemithyroidectomy was carried out in 67 patients on account of a "cold nodule" while the remaining 33 patients were submitted to operation on other indications. Out of the 67 patients, one (2%) had a papillary carcinoma, 53 (79%) had follicular adenomata, 12 (18%) had nodular goitre and one (2%) had Hashimoto's thyroiditis. In the entire material, one case (1%) of permanent hypocalcaemia was encountered. None of the patients developed paresis of the recurrent laryngeal nerve. Reoperation proved necessary in one patient (1%) on account of postoperative heamorrhage. It is concluded that hemithyroidectomy is a rational primary method of treatment in cases with suspected malignant disease in the thyroid gland. Non-neoplastic conditions may be excluded with reasonable certainty by preoperative clinical assessment and thyroid scintigraphy and ultrasound scanning. The intervention is safe and every thyroid surgeon should be capable of performing the operation.

Adult↗
PubMed1991

Heterogeneity of postjunctional alpha-adrenoceptors in isolated mesenteric resistance arteries from rats, rabbits, pigs, and humans.

Mesenteric resistance arteries (internal diameter 174-337 microns) from rats, rabbits, pigs, and humans were isolated and mounted in a myograph. In all preparations, phenylephrine (alpha 1-adrenoceptor agonist) evoked concentration-dependent contractions that were antagonized by prazosin (alpha 1-adrenoceptor antagonist). B-HT 933 (alpha 2-adrenoceptor agonist), however, did not evoke contractions in any rat or rabbit vessels. In contrast, this agonist elicited contractions in some (five of 15) porcine and all (18) human vessels; in the vessels responsive to B-HT 933, the maximum responses amounted to 53 +/- 7 and 79 +/- 6%, respectively, of the responses to high potassium. The affinities of yohimbine (alpha 2-adrenoceptor antagonist) for the receptors mediating responses to B-HT 933 were 7.46 +/- 0.13 (pKB) and 7.57 +/- 0.10 (pA2), respectively. Prazosin (10(-8) M) antagonized the responses to norepinephrine in all preparations, whereas yohimbine (10(-7) M) caused significant inhibition of these responses in human vessels only; moreover, the inhibition in these vessels of the responses to norepinephrine caused by the combination of these two antagonists was greater than the antagonism caused by either antagonist alone. These results suggest the presence of postjunctional alpha 1-adrenoceptors that are involved in responses to norepinephrine in mesenteric resistance arteries from all species examined. Functional, postjunctional alpha 2-adrenoceptors appear to be present in porcine and human vessels, but this receptor seems to be involved in responses to norepinephrine in human vessels only.

Adrenergic beta-Agonists↗
PubMed1991

Alpha-adrenoceptors in human resistance arteries from colon, pericardial fat, and skeletal muscle.

Human resistance arteries (144-332 microns diam) from colon, pericardial fat, and skeletal muscle were mounted in a myograph for measurements of isometric contractions under conditions of partial depolarization by potassium chloride. In all preparations, both phenylephrine (alpha 1-selective agonist) and B-HT 933 (alpha 2-selective agonist) evoked concentration-dependent contractions that were antagonized by the alpha 1-selective antagonist prazosin (10(-8) M) and the alpha 2-selective antagonist yohimbine (10(-7) M), respectively. The affinities (expressed as pKB values) of prazosin for the receptor mediating the responses to phenylephrine were 8.88-9.41, whereas the affinities of yohimbine for the receptor mediating the responses to B-HT 933 were 7.71-7.97. Norepinephrine (mixed alpha 1-agonist/alpha 2-agonist) also elicited concentration-dependent responses that were modestly, but significantly, antagonized by prazosin alone and yohimbine alone at the above-mentioned concentrations. The two antagonists in combination, however, effectively antagonized the responses to this agonist. These findings strongly suggest the presence of functional, postjunctional alpha 1- and alpha 2-adrenoceptors in isolated human resistance arteries from colon, pericardial fat, and skeletal muscle and that responses to norepinephrine in these vessels are mediated by both alpha-adrenoceptor subtypes.

Adipose Tissue↗
PubMed1991

Valve replacement for calcified aortic stenosis in septuagenarians infers normal life-length.

Aortic valve replacement because of pure or predominant stenosis was performed in 1970-1986 on 101 patients aged 70-78 years, including 80 in NYHA function class III or IV. There were 16 deaths within 30 days, and coronary artery disease (unbypassed in all but 1 case) was found in 11 of the 13 with autopsy or preoperative arteriography. None of the 12 patients without significant coronary artery disease at angiography died perioperatively,but one of 12 with combined valve replacement and coronary artery bypass grafting died. Cumulative 1-year survival among the 101 patients/the 85 survivors of the first 30 days and/a normal population matched for sex, age and year of operation was 75/90/96%. Corresponding percentages for 5 years were 64/75/77, for 10 years 43/52/52, and for 15 years 35/42/27. Advanced disease with kidney failure or left ventricular end-diastolic pressure greater than 20 mmHg independently increased the overall mortality rate. The linearized rat of cerebral events (haemorrhage, embolism) was 2.7/100 patient years (age-specific background rate 1.6-1.9/100 patient years). The 30-day mortality among septuagenarians was reduced to 3% in 1988-1989 by routine revascularization in significant coronary artery disease. The patients who survived the first 30 days had normal life expectancy. Early operation may further improve the results.

Aged↗
PubMed1991

Twenty-two-year experience with aortic valve replacement. Starr-Edwards ball valves versus disc valves.

From 1965 through 1986, 817 patients underwent aortic valve replacement at our institution. Six hundred forty-five patients received Starr-Edwards ball valves, including 286 Silastic ball valves (Models 1200/1260), 165 cloth-covered caged-ball prostheses (Models 2300/2310/2320), and 194 track-valve prostheses (Model 2400). In contrast, 172 patients received disc-valve prostheses, including 126 St. Jude Medical aortic bi-leaflet disc valves, 32 Lillehei-Kaster pivoting disc valves, and 14 Björk-Shiley valves (6 convexoconcave and 8 monostrut). With respect to preoperative data, the 2 groups were comparable, with the following differences. The Starr-Edwards group included 1) more men (77% versus 51%; p < 0.0001); 2) a significantly older patient population (59 +/- 10 years versus 56 +/- 15 years; p < 0.0001); 3) more patients in New York Heart Association functional class III or IV (72% versus 65%; p < 0.01); 4) fewer patients with angina pectoris as a limiting symptom (20% versus 36%; p < 0.0001); and 5) patients who tended to receive larger prostheses (26 +/- 2 mm versus 23 +/- 3 mm, p < 0.0001). The overall 10-year survival rate +/- standard error was 59% +/- 2% for patients receiving Starr-Edwards valves and 63% +/- 6% for those with disc valves. The linearized complication rates (expressed as percentage per patient-year +/- standard error) for the Starr-Edwards and disc-valve groups, respectively, were 2.0% +/- 0.2% and 1.4% +/- 0.5% for thromboembolism, 2.1% +/- 0.2% and 3.9% +/- 0.8% for Coumadin-related hemorrhage, 0.5% +/- 0.1% and 0.3% +/- 0.2% for endocarditis, 0.3% +/- 0.1% and 0.7% +/- 0.3% for other prosthesis-related complications, and 4.8% +/- 0.1% and 6.4% +/- 1.0% for all complications together. There were no instances of thrombotic occlusion or mechanical failure. After the 6th postoperative year, no thromboembolic events were encountered in patients with a Silastic ball valve; the 15-year freedom from thromboembolic events was 89%. Cox regression analysis showed that 1) a prosthetic orifice diameter of 15 mm or less was associated with an increased mortality; 2) disc valves entailed an increased rate of hemorrhage and prosthesis-related complications considered as a whole; 3) and Lillehei-Kaster valves led to an increased rate of prosthesis-related complications other than thromboembolism, hemorrhage, and endocarditis. Neither the type of prosthesis nor the size influenced the rate of thromboembolism, endocarditis, or prosthesis replacement. Because of their proven durability and relatively low price, we advocate the continued use of Starr-Edwards Model 1260 Silastic ball valves that have an orifice diameter of 16 mm or more.

Journal Article↗
PubMed1990

[Prosthesis-endocarditis in the aortic position in a 22-year case load. Surgical versus conservative treatment].

During the period 1965-1986, a total of 852 patients underwent isolated aortic valve replacement. With 4,875 patients-years at risk, 24 patients developed prosthetic valve endocarditis (PE; 0.49% per patient-year). The five, ten and fifteen year cumulative freedoms from PE were 98.2%, 95.4% and 93.0%, respectively. PE was unrelated to pre- or intraoperative data. No patients submitted to operation for acute/subacute bacterial endocarditis of the native aortic valve developed PE. Out of the 12 episodes of PE within two years of the operation, seven (58%) were caused by Staphylococcus albus compared with two out of 12 (17%; p less than 0.05) subsequent episodes of PE. Seven of the nine infections with Staphylococcus albus were caused by a highly resistant nosocomial variant. Ten of the PE patients underwent replacement of the prosthesis while 14 were treated conservatively. The two therapeutic groups were comparable, although the surgically treated patients tended to be younger and to have more impaired cardiac status. All surgically treated patients and all patients treated conservatively and in whom post mortem verification was possible had paravalvular defects, annular abscesses and/or vegetations on the prosthesis. The thirty-day, one year and ten year cumulative survivals were 80%, 80% and 50%, respectively, after replacement of the prosthesis and 64%, 21% and 7%, respectively, after conservative treatment (p = 0.02). A Cox regression analysis identified conservative treatment, infection with Escherichia coli or Haemophilus influenzae and the need to intensify digitalis/diuretic treatment for congestive heart failure as independent risk factors. It is concluded that replacement of the prosthesis early in the course of the disease should be considered as the treatment of choice.

Adolescent↗
PubMed1990

[Mesenterial fibromatosis].

The article presents a case of a rare tumor, mesenteric fibromatosis, unassociated with Gardner's syndrome and without previously abdominal surgery. The author reviews symptoms, diagnostic features and treatment, and discusses some of the possible differential diagnoses.

Anastomosis, Surgical↗
PubMed1990

Long-term prosthesis-related and sudden cardiac-related complications after valve replacement for aortic stenosis.

Predictability of prosthesis-related and sudden cardiac-related complications was examined in 630 patients who were alive 30 days after valve replacement (1965 to 1986) for aortic stenosis. Follow-up totaled 4,072 patient-years. A variety of prosthetic valves, mainly mechanical, were used. The Cox regression model was used to identify independent risk factors and to estimate predicted event-freedoms relative to combinations of these risk factors. There were no risk factors for endocarditis (0.5 +/- 0.1 [number of events per 100 patient-years +/- the standard error]). Except for "other" prosthesis-related complications (0.4 +/- 0.1), adversely influenced by porcine bioprostheses (n = 15) and by the Lillehei-Kaster prosthesis (n = 25), only factors underlying diseased preoperative patient/cardiac status had predictive influence. Predicted 10-year event-freedoms for low-risk versus high-risk estimate were 86% versus 73% for thromboembolism (1.7 +/- 0.2), 95% versus 32% for anticoagulant-related hemorrhage (2.4 +/- 0.2), 69% versus 36% for all prosthesis-related complications (5.0 +/- 0.4), 93% versus 0% for sudden cardiac-related events (myocardial infarction and arrhythmia) (1.8 +/- 0.2), and 66% versus 0.5% for combined prosthesis-related and sudden cardiac-related morbidity and mortality (6.8 +/- 0.4). In 193 patients with coronary arteriography, coronary artery disease was a significant risk factor for each of the complication modalities examined except other prosthesis-related complications, prosthesis replacement, and endocarditis. Deciding to operate early in the course of aortic stenosis might "actively" reduce the rate of these complications.

Adult↗
PubMed1990

Valve replacement for aortic regurgitation: earlier operation may reduce the rate of late complications related to the prostheses.

Predictability of prosthesis- and sudden heart-related complications was examined in 121 patients who were alive 30 days after valve replacement (1965-86) for aortic regurgitation. A variety of prosthetic valves, mainly mechanical, were used. The Cox regression model was used to identify independent risk factors and to estimate the predicted freedom of events relative to combinations of these risk factors. In the following, linearized event-rates (LER) are given as number of events per 100 patient years +/- standard error. No risk factors could be identified for endocarditis (LER: 0.3 +/- 0.2) or anticoagulant-related hemorrhage (LER: 1.7 +/- 0.6). Only factors underlying deranged preoperative patient and heart status and cardioplegic method, but not the type of prosthetic valve, had predictive influence on the other complications. Predicted 10-year event-freedoms for low- versus high-risk estimate were 98% versus 46% for thromboembolism (LER: 2.1 +/- 0.6), 87% versus 68% for all prosthesis-related complications (LER: 5.0 +/- 0.8), 100% versus 0% for sudden heart-related events (LER: 2.0 +/- 0.5; myocardial infarction and arrhythmia), and 72% versus 38% for combined prosthesis- and sudden heart-related morbidity and mortality (LER: 7.0 +/- 1.0). By deciding to operate early in the course of aortic regurgitation, the rate of these complications may be "actively" reduced, and longevity and life quality of the patients improved.

Adult↗
PubMed1990

Long-term performance of Starr-Edwards silastic ball valves and St Jude Medical bi-leaflet valves. A comparative analysis of implantations during 1980-86 for aortic stenosis.

Long-term performance of Starr-Edwards silastic ball (SESB, n = 168) and St Jude Medical bi-leaflet (SJMB, n = 93) valves in patients who were alive 30 days after implantation (1980-86) for aortic stenosis was compared. Mean follow-up was 3.0 years (0.1-7.9 years). The SESB and SJMB groups differed as regards female gender (18% vs 47%, P less than 0.0001), NYHA classes III-IV (59% vs 72%, P less than 0.05), coronary artery disease (CAD, 32% vs 62%, P less than 0.01) in patients with coronary arteriography (n = 82 and n = 55, respectively), and prosthetic annulus diameter (26 +/- 1 vs 23 +/- 2 mm, P less than 0.0001). Five-year survival +/- SE in SESB vs SJMB patients was: total population, 89 +/- 3% vs 80 +/- 6% (NS); coronary arteriography population, no CAD, 90 +/- 4% vs 100% (NS), and with CAD, 71 +/- 11% vs 60 +/- 13% (NS; P = 0.01 for CAD). Five-year event-free survival +/- SE in SESB vs SJMB patients was 95 +/- 2% vs 97 +/- 2% (NS) for thromboembolism, 95 +/- 2% vs 89 +/- 4% (NS) for coumadin-related haemorrhage, 98 +/- 1% vs 99 +/- 1% (NS) for endocarditis, 98 +/- 1% vs 94 +/- 5% (NS) for paravalvular leak, 88 +/- 3% vs 79 +/- 6% (NS) for all valve-related complications, and 98 +/- 1% vs 95 +/- 4% (NS) for prosthesis replacement. Thrombotic occlusion or structural failure were not observed. No patients without CAD experienced thromboembolic events. Cox regression analyses (in both total population and coronary arteriography population) of survival as well as the various complications revealed that the type of prosthesis did not have predictive influence. CAD was an independent risk factor for thromboembolism, haemorrhage, and all valve-related complications. Previous systemic hypertension was independently predictive of haemorrhage. The SESB and SJMB prostheses showed comparable and acceptable long-term performance. Only patient-related variables, notably CAD, influenced late results. The proven durability and relatively low price of the SESB valves together with the excellent haemodynamic performance of even small-sized SJMB valves should be considered in the light of the present results.

Adolescent↗
PubMed1990

[Vascular surgery in Denmark].

This report presents vascular surgical operations performed in Denmark 1983-1987, the first five years after the establishment of the speciality. The number of vascular surgical operations increased by 18 per cent during the five years to nearly 2,000 operations in 1987. Approximately 50 per cent of all vascular procedures were intraabdominal operations, while 30 per cent were peripheral reconstructions. In 1987 40 operations/100,000 inhabitants were made, a level considerably below the activity performed in the other Scandinavian countries. We conclude that vascular surgical activity will increase in Denmark in the years to come.

Denmark↗
PubMed1990

The influence of coronary artery disease and bypass grafting on early and late survival after valve replacement for aortic stenosis.

The influence of coronary artery disease and bypass grafting on survival after valve replacement for aortic stenosis (1975 to 1986, N = 512) was analyzed. Mean follow-up for 30-day survivors was 5.1 years (0.1 to 12.9 years). A total of 205 patients had coronary angiography performed: 122 did not have coronary artery disease, 55 with coronary artery disease underwent bypass grafting, and 28 with coronary artery disease did not. Early mortality rates (less than or equal to 30 days)/5-year cumulative survivals (standard error) were 4.1%/86% (4%), 3.6%/68% (8%), and 17.9%/51% (13%), respectively (p less than 0.05/p less than 0.01). Triple vessel/left main stem disease was more prevalent in patients with coronary disease who underwent bypass grafting (47%) than in those who did not (14%; p less than 0.05). Multivariate analysis revealed that right ventricular failure and omission of bypass grafting in patients with coronary artery disease were independent determinants of early mortality. A Cox regression analysis identified coronary artery disease and aortic valve gradient as determinants of mortality after hospital dismissal, which was not influenced by bypass grafting. On the basis of a coronary artery disease score (positive predictive value for coronary artery disease of 66%) developed on the patients with angiography, 307 patients without angiography were divided into 234 with a low score and 73 with a high score. Early mortality rates/5-year survivals (standard error) were 6.4%/86% (2%) and 16.4%/67% (6%), respectively (p less than 0.01/p less than 0.001). Autopsy revealed stenotic or occlusive coronary artery disease in 92% of 12 early deaths in the group with a high coronary artery disease score and in 33% of 15 in the group with a low score (p less than 0.01). Left ventricular failure and a high coronary artery disease score were independent determinants of early mortality, whereas cardiothoracic index, a high coronary artery disease score, and left ventricular failure were independent predictors of death after hospital dismissal. Despite more severe coronary artery disease, bypass grafting reduced early mortality to a level comparable with that of patients without coronary artery disease, contrasting with a high early mortality rate for unbypassed coronary artery disease. Coronary artery disease increased the late mortality rate, which was not modified by bypass grafting. In the group without angiography, undiagnosed and unbypassed coronary artery disease probably increased both early and late mortality. Coronary angiography should be performed in all adult patients with aortic stenosis, and those with significant coronary artery disease should undergo bypass grafting concomitant with valve replacement.

Aortic Valve Stenosis↗
PubMed1989

Early and late prognosis after valve replacement in aortic regurgitation. Preoperative risk stratification and reasons for a more aggressive surgical approach.

From 1965 through 1986 136 patients underwent valve replacement for aortic regurgitation. Mean age was 50 years and male:female ratio 3.7:1. Hospital mortality (HM, less than or equal to 30 days) varied with NYHA classes and digitalis/diuretics treatment (D/D):I (n = 80) 0%, II without D/D (n = 17) 0%, II with D/D (n = 21) 5%, III (n = 55) 7%; and IV (n = 35) 29% (p less than 0.01). Long-term survival was examined for 121 patients who were alive 30 days postoperatively. Five- and 10-year cumulative survival +/- SE were 80 +/- 4% and 66 +/- 6%, respectively. No late deaths were noted for NYHA class I and NYHA class II without D/D; NYHA class II with D/D had survival characteristics comparable to NYHA class III with 10-year survivals of 60%. Patients with acute regurgitation (endocarditis, n = 35) had a 10-year survival +/- SE of 88 +/- 5% compared to 57 +/- 7% for chronic regurgitation (p = 0.05). A Cox regression analysis revealed that ventricular ectopic beats, chronic regurgitation, left ventricular failure, and right ventricular failure were independent risk factors. Presence and different combination of these risk factors identified 5 risk groups (A-E) with 10-year survivals of:A (n = 16) 100%; B (n = 50) 75%; C (n = 37) 63%; D (n = 15) 27%; and E (n = 3) 0% (p less than 0.0001). Minimally symptomatic patients without preoperative medical treatment for congestive heart failure had superior survival characteristics compared to those who received treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Mental function in elderly men after surgery during epidural analgesia.

To evaluate whether there is a difference in mental function after general anaesthesia and epidural analgesia, a homogeneous group of 40 elderly men (age between 60 and 80) undergoing transurethral prostatectomy was studied. The study was prospective, randomised and double blind. Patients with all types of complications believed to impair mental function were excluded. Long-term, short-term, verbal and visual memory were tested preoperatively, and 4 days, and 3 weeks postoperatively. In conclusion, we found a significant and equal decline in test performance on the fourth postoperative day. Three weeks postoperatively, however, both groups had returned to or exceeded preoperative levels of performance.

Aged↗