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Biomedical subjects

U Althaus

Publications and source records attributed to U Althaus.

At least 91 records · Page 5Linked to original sources
PubMed1991

2,3-butanediol in experimental myocardial ischaemia in pigs.

To investigate the role of 2,3-butanediol in myocardial ischaemia we analysed this compound in pig's myocardium and blood. Ischaemia was induced by ligation of a coronary artery. In the first study we found significantly higher levels of 2,3-butanediol in the homogenate of ischaemic myocardium than in non-ischaemic myocardium. The lactate concentration was also significantly elevated. In the second study, where ischaemia was similarly induced, and where reperfusion was achieved by re-opening the ligated coronary artery after 20 min, 2,3-butanediol in peripheral blood was found to increase significantly. In the pigs in which the coronary artery was not re-opened, the 2,3-butanediol level in peripheral blood was unchanged. We conclude that in pigs' anaerobic myocardia accumulation of 2,3-butanediol occurs; if the myocardium is reperfused this metabolite also appears in the blood.

Animals↗
PubMed1990

[Quantitative and qualitative analysis of various blood-preserving measures in heart surgery].

We assessed quantitative aspects of blood salvage retrospectively in 270 consecutive coronary bypass patients over one year. They were assigned either to group A (n = 10, Cellsaver [Haemonetics]), B (n = 189, centrifugated oxygenator blood), C (n = 107, retransfusion of shed mediastinal blood) or D (n = 74, combination of method B and C). In addition, blood quality was studied prospectively in group A (n = 5), B (n = 10) and C (n = 10) and each group compared to a control group. Results (mean values/patient) were: Blood salvage with A yielded 570 +/- 230 ml (hematocrit = 50%), B 509 +/- 156 ml (69%) and C 593 +/- 430 ml (26%). The required homologous blood products, i.e. packed cells (PC) and fresh frozen plasma (FFP) diminished significantly when combined autologous blood salvage was used (PC 6.0 +/- 3.4 vs 3.4 +/- 1.9, p less than 0.05; FFP 3.4 +/- 3.8 vs 2.6 +/- 3.0). Autologous erythrocyte function assessed by 2,3DPG was normal in all three methods (range 14.77-16.03 mumol/gHb). ATP was nearly normal in A (3.34 +/- 0.45 mumol/gHb), reduced by 20% in B (3.21 +/- 1.14 mumol/gHb) and by 30% in C (2.56 +/- 0.78 mumol/gHb) compared to the corresponding preoperative patient value. Hemolysis (free plasma hemoglobin) (was elevated in A (63 +/- 7 mg/dl), B (202 +/- 57 mg/dl) and C (211 +/- 44 mg/dl). However, no increase of free plasma hemoglobin was encountered in our patients after retransfusion of either A, B or C. No side effects were detected and bacteriology remained negative in all examined blood samples in C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1990

[Severe hemolytic anemia following purse-string valvuloplasty of the mitral valve].

A patient who had undergone valvuloplasty for mitral insufficiency due to chordal rupture developed severe hemolytic anemia a few weeks after surgery. Progressive mitral regurgitation was noted at the same time. Extensive laboratory workup excluded other reasons for hemolytic anemia. In comparison with other cases in the literature it is assumed that the patient was suffering from cardiogenic mechanical hemolysis. Fourteen months later mitral valve replacement (St Jude) was performed and the hemolysis ceased promptly. A brief review of the literature is presented.

Aged↗
PubMed1990

Ultrastructural and biochemical findings in brain cell cultures infected with canine distemper virus.

To study the pathomechanism of demyelination in canine distemper (CD), dog brain cell cultures were infected with virulent A75/17-CD virus (CDV) and examined ultrastructurally. Special attention was paid to the oligodendrocytes, which were specifically immunolabelled. In addition, cerebroside sulfotransferase (CST), an enzyme specific for oligodendrocyte activity was assayed during the course of the infection. Infection and maturation as well as CDV-induced changes were found in astrocytes and brain macrophages. Infection of oligodendrocytes was rarely seen, although CST activity of the culture markedly decreased and vacuolar degeneration of these cells occurred, resulting in their complete disappearance. We concluded that the degeneration of oligodendrocytes and demyelination is not due to direct virus-oligodendrocyte interaction, but due to CDV-induced events in other glial cells.

Animals↗
PubMed1990

Accidental deep hypothermia with cardiopulmonary arrest: extracorporeal blood rewarming in 11 patients.

Sixteen patients (age 13-53 years) with accidental deep hypothermia have been rewarmed in our clinic during the last 10 years, 14 by femoro-femoral cardiopulmonary bypass (CPB) of whom 11 had a cardiopulmonary arrest (asystole in 5 and ventricular fibrillation in 6). On admission, the latter were clinically dead showing wide non-reactive pupils and being supported by ventilation and external heart massage. In the survivors, the mean length of cold exposure was 4.4 h (2-5.5 h) and mean arrest interval until initiation of CPB was 2.5 h (1.4-3.7 h). Rectal temperature on admission ranged from 17.5 degrees C to 26 degrees C (mean 22.5 degrees C). The causes for hypothermia were fall into a crevasse (5), avalanche (1), drowning (2) and cold exposure (3) including 2 suicide attempts. Results are summarized in the following table: [table: see text] Eight of the 11 patients with deep hypothermia and cardiac arrest were rewarmed and resuscitated successfully with CPB. Three patients, including 2 cases of asphyxia (avalanche and drowning), could not be weaned from CPB despite adequate rewarming. The other drowned patient (53 years) died on the 3rd postoperative day (POD) from ARDS. The main complication was pulmonary edema (57%) and transient neurological deficits. All survivors became conscious during the first POD and resumed, their professional activity. We conclude that patients with accidental deep hypothermia and even prolonged cardiopulmonary arrest should be rewarmed and resuscitated rapidly by cardiopulmonary bypass. These measures are very promising particularly if the cause of accident and the circumstances suggest that cardiopulmonary arrest was induced by hypothermia alone without other asphyxiating mechanisms.

Adolescent↗
PubMed1990

[Heart and vascular surgery interventions with hypothermic circulatory arrest in adults].

In the period between 1981 and 1988, 51 patients were operated on the thoracic aorta using the hypothermic circulatory arrest technique. 31 patients had a dissection of the thoracic aorta, in 16 cases, an aneurysm was the reason for the intervention. In addition, we used the hypothermic circulatory arrest for a thrombectomy in the aortic arch and two mitral-valve replacements. The following operations were performed: 14 x composite graft, 19 x supracoronar prosthesis (6 x with aortic valve replacement, 3 x with partial replacement of aortic arch), 17 operations were performed either for aortic arch or aorta descendens replacement. In our retrospective study, 7 courses were fata (14%), 3 patients had complications with residuals. Compared with a group of 105 patients operated on the thoracic aorta in the same period without circulatory arrest, we found no difference with regard to the lethality and morbidity. We conclude that the hypothermic circulatory arrest is a safe technique for selected problems in cardiovascular surgery in adults.

Aortic Dissection↗
PubMed1990

[Risk factors for neurologic complications in aortocoronary bypass surgery].

In a prospective study risk factors for neurological complications were evaluated in 300 unselected patients undergoing open heart surgery due to coronary artery disease. Patients with combined procedure (aorto-coronary bypass graft and valve replacement) were excluded from the study. Six patients (2%) suffered from a neurological event in the early postoperative period. A strong risk factor is the age (65 +/- 6 years in the symptomatic group, 56 +/- 9 years in the asymptomatic group, p = 0.009, Student-t-test, double-sided). A certain tendency is seen in patients with carotid stenosis (17% in the symptomatic group, 5% in the asymptomatic group), in patients with a positive neurological history (17% in the symptomatic group, 1% in the asymptomatic group) and in patients with operative revision (33% in the symptomatic group, 4% in the asymptomatic group). No difference was seen in the risk factors sex, lesions of the middle cerebral artery and the ECC-time.

Aged↗
PubMed1990

[Evaluation of recent vascular prostheses in the arteriovenous shunt].

Prosthetic vascular replacement materials are still suboptimal especially for distal peripheral and coronary bypass grafts due to the small caliber and high occlusion rates. Therefore new vascular grafts have been assessed with respect to blood compatibility, thrombogenicity and host pretreatment. In 12 heparinized minipigs (25 kg), a total of 120 small caliber grafts (i.d. 3.0 mm) were perfused (6 min) in a femoro-femoral arteriovenous shunt (AVS). Materials included: Dacron (Atrium), PTFE (Gore), Polyurethanes (PU), Auto- and Xenografts. Animals were treated preoperatively with fishoil (3 g EPA/QD x 3 weeks = group I), perioperatively with prostaglandins (PGE1 = group II) or with fishoil and graft incubation in plasma proteins (= group III) and compared to controls without pretreatment (= group 0). We measured flow, deposition of marked thrombocytes (HMPAO-Tc* per area and per weight). - Blood flow was similar in AVS for all groups and materials (168 +/- 86 ml/min, p = NS). There was no significant correlation in deposition of marked thrombocytes and host pretreatments (group 0: controls = 7356 counts/area, group I: fishoil = 6807. group II: PGE1 = 7864). However graft incubation in plasma proteins significantly lowered deposition of marked thrombocytes (1766 in group III vs. 7356 in group 0: p less than 0.05). And significant differences of thrombocyte counts where found between the different materials: Autografts less than PTFE less than Xenografts less than Small Pore PU less than Dacron less than Large Pore PU.--AVS is a useful tool to determine early thrombogenicity in prosthetic vascular replacement materials and to assess the effect of different host pretreatments.

Animals↗
PubMed1990

[Transitory subclavian steal induced by abnormal position of the arm and producing dangerous myocardial ischemia after mammary artery bypass].

Literature reports only eleven cases of subclavian steal syndrome after CABPG through a left internal mammary artery (LIMA). In 2 asymptomatic patients the diagnosis was established at routine control angiography. In all cases some degree of stenosis of the subclavian artery (SCA) proximally to the emergence of the LIMA was demonstrated and quickly corrected by means of a left carotido-subclavian bypass graft. We report the observation of a patient who presented already at the 11th postoperative day recurrent instable angina with typical ECG changes. This case is absolutely exceptional for two reasons: Postoperative angina appeared exclusively during sleep but never under exercise. Careful interrogation revealed that the patient always slept with his hands crossed under the neck, in a position comparable to the Adson test. In this critical position of the arms, typical attacks of angina and ECG changes could be easily and repetitively induced. A steal syndrome though the LIMA bypass could be demonstrated at coronary angiography and simultaneous measures of the systolic blood pressure on both arms revealed a difference over 20 Torrs which became apparent exclusively in upright position of the arms. All the symptoms disappeared spontaneously within a few months. Six months postoperatively the ECG was normal even in the upright position of the arms and no blood pressure difference could be evidenced anymore. A control coronary angiography showed a patent and well-functioning LIMA graft on the LAD and the absence of any retrograde perfusion of the LIMA graft. These different transitory symptoms have probably to be related to a postoperative compression of the proximal SCA by hematoma or by oedematous reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Retransfusion of thoracic drainage blood: qualitative analysis].

In a prospective randomized study 10 patients received their shed mediastinal blood after elective coronary artery bypass surgery and were compared to 10 control patients without retransfusion. The quality assessment can be summarized as follows (mean +/- 1 SD): 1. Hemoglobin concentration of the shed blood was 9.6 +/- 1.45 g/dl. 2. The energy rich phosphate compounds of the shed blood erythrocytes were 2.6 +/- 0.8 mumol/gHb ATP (70% of the patients preoperative value) and 14.8 +/- 4.2 mumol/gHb 2.3-DPG (normal). 3. Proteins, immunoglobulins and especially albumin in the shed blood were not significantly different from the patients own values. 4. No electrolyte changes, safe for a slight increase in potassium (5.7 +/- 0.7 mmol/l). 5. The activated clotting time of the patient did not change during retransfusion. 7. Plasma free hemoglobin was elevated to 211.1 +/- 44.3 mg/dl in the shed blood; however, no significant increase could be noted in the retransfused patients and no hemoglobinuria occurred. Postoperative retransfusion of shed mediastinal blood is a simple and safe method of autologous transfusion early after cardiac surgery and should be combined with other methods of blood salvage. The qualitative advantages of blood retransfusion consist in the absence of storage damage and in the preservation of autologous proteins and immunoglobulins.

Blood Chemical Analysis↗
PubMed1989

[Duplex and transcranial sonography in the preoperative evaluation of cerebrovascular circulation before heart operations].

Fifty unselected patients undergoing open heart surgery (OHS) were examined by duplex and transcranial Doppler sonography. Two high degree (greater than 75%) carotid stenosis were found in 70 carotid arteries of 35 patients with coronary artery disease. Fourteen vessels had unmistakable signs of extracranial vascular disease whilst 54 carotid arteries were identified as normal. Two high degree (greater than 75%) carotid stenosis were found in 30 vessels of 15 patients with valvular disease. Seven other vessels had a low grade stenosis or excessive atheroma, whereas 21 were identified as normal. The rate of about 5-10% asymptomatic high grade carotid stenosis in patients undergoing OHS justifies routine noninvasive examination of the cerebral circulation by duplex and transcranial Doppler sonography. Patients with high grade stenosis are offered a follow-up preventive programme against cerebral infarction, which consists of 3 steps: 1. anti-platelet aggregating drugs, 2. periodic control examinations by duplex and transcranial Doppler sonography, and 3. continued evaluation of indication for carotid endarterectomy.

Adult↗
PubMed1988

[Therapy of valvular stenosis: surgical treatment vs percutaneous balloon dilatation].

Balloon valvuloplasty has been recommended as an alternative to surgery, and therefore this new procedure needs to be compared with cardiac valve replacement. In our experience with 284 consecutive patients, hospital mortality was 1.8% (including multiple valve replacement); 5 years postoperatively survival was 92%, and 94% of the patients had an embolism-free course. To investigate the efficiency of balloon valvuloplasty, this procedure was carried out under direct vision in the operating room prior to excision and replacement of the calcified aortic valve. In two-thirds of patients balloon dilatation did not have a detectable impact on valvular anatomy. In clinical reports the calculated mean aortic valve area did not exceed 1 cm2 (orifice area of the St. Jude valve No. 25 = 3.07 cm2). A good functional result can only be expected from mitral balloon valvuloplasty in the absence of sclerotic alterations of the subvalvular structures. As regards the risk of balloon valvuloplasty for the patient, hospital mortality associated with this procedure is not below that of surgical valve replacement (6.2% in the French Registry for balloon dilatation, 1.8% in our own experience for surgical patients aged over 70 years). An alarming observation is that the beneficial effect of aortic balloon valvuloplasty on the pressure gradient ceases within a relatively short period. For patients with mitral balloon dilatation the risk of arterial thromboembolism and the development of valvular regurgitation must be taken into consideration. The area of clinical application for Balloon valvuloplasty can at present be outlined as follows. The procedure is regarded as the treatment of choice only for pulmonary stenosis. For congenital and rheumatic aortic valve stenosis balloon dilatation may be a useful method for younger individuals if the cusps are not immobilized by calcified masses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Correlation between 31P NMR phosphomonoester and biochemically determined phosphorylethanolamine and phosphatidylethanolamine during development of the rat brain.

Phosphomonoesters were measured in the developing rat brain by in vivo and in vitro 31P nuclear magnetic resonance (NMR) spectroscopy and by classical biochemical methods. In vitro NMR showed that the main component of the phosphomonoester peak is phosphorylethanolamine. Phosphomonoesters measured by in vivo NMR decreased during development at the same rate as the biochemically estimated phosphorylethanolamine. Phosphorylethanolamine, a precursor of the membrane lipid phosphatidylethanolamine, decreased during development parallel to an increase of the lipid phosphatidylethanolamine, which was measured biochemically. These studies show that 31P NMR can be used to monitor brain development in vivo.

Aging↗
PubMed1988

Duplex scanner study of carotid artery dissection following surgical treatment of aortic dissection type A.

In patients suffering from aortic dissection, persistent perfusion of the false lumen distal to the implanted graft is frequent. Postoperative follow-up examinations of the carotid arteries of these patients were performed by duplex scanner and correlated with clinical symptoms. Thirty-nine patients who survived the surgical treatment of acute type A aortic dissection had duplex sonography of both common carotid arteries after an average postoperative follow-up of 53 months. In 21 cases a composite graft and in 18 cases a supracoronary prosthetic vascular graft were implanted. No sign of residual dissection of the common carotid arteries was seen in 23 patients; in nine there was a dissection of both common carotid arteries, and seven patients had a unilateral carotid dissection (five right, two left). There were nine symptomatic patients with the following symptoms: transient ischemic attack (four), amaurosis fugax (four), stroke with incomplete recovery (one). Two symptomatic patients had a corresponding dissection. The generally good prognosis of all these patients suggests a conservative nonoperative treatment.

Aged↗
PubMed1988

Heart valve replacement with St. Jude Medical valve prosthesis. Long-term experience in 743 patients in Switzerland.

Between November 1978 and June 1986, 828 St. Jude Medical valves were implanted in 743 patients whose mean age was 57 years (range, 1-83 years) and who had been admitted to the University Hospitals in Basel, Berne, and Lausanne, Switzerland. Aortic valve replacement was performed in 456 patients, mitral valve replacement in 200, tricuspid valve replacement in six, double valve replacement in 77, and triple valve replacement in four. In 187 patients, additional surgical interventions were performed. Operative mortality was 1.6%, and the 4-week postoperative mortality was 4.0%. During a mean follow-up period of 2.6 years, the annual mortality rate was 3.1%, and the annual cardiac mortality rate was 2.1%. The thromboembolic rate per 100 patient-years was 1.3 after aortic valve replacement, 3.0 after mitral valve replacement, and 1.0 after multiple valve replacement. The incidence of major bleeding was 1.3 per 100 patient-years. Valve dysfunction attributable to thrombotic obstruction occurred in three patients, and that attributable to leaflet dislocation in one (annual dysfunction rate, 0.2%). Twelve patients developed infectious endocarditis, six of whom died. However, in four patients, reoperation and, in two patients, antibiotic treatment alone were successful in treating the infection. A paravalvular leak necessitating reoperation developed in 10 patients. In three patients, the leak was caused by infectious endocarditis. Reoperation had no operative mortality. In three patients (0.4%), a mild hemolytic anemia was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗