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Biomedical subjects

B Höfling

Publications and source records attributed to B Höfling.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Return of circadian blood pressure and heart rate changes in patients with heart transplants].

A loss of the circadian rhythm pattern of blood pressure (BP) and heart rate, as well as the development of hypertension have been found after heart transplantation (Htx). To study whether a return of this rhythm occurs in the long-term after Htx, we used 24-h ambulatory monitoring to study 62 patients 5 days to 6.5 years after Htx. Patients were divided into two groups (Group 1: less than 6 months after Htx (n = 30), Group 2: 6 months or more after Htx (n = 32)). Group 2 had a higher BP and heart rate, as well as a significantly higher difference between systolic day and systolic night BP than group 1. There was also a significantly higher difference in heart rate between day and night values in group 2. The return of the circadian rhythm pattern in the longer term after heart transplantation may result from partial reinnervation of the heart, although other neurohumoral factors or concomitant medication may play a role.

Adrenergic beta-Agonists↗
PubMed1992

[In situ detection of EGF receptor mRNA in arteriosclerotic lesions in man: implications for the proliferative activity of smooth muscle cells].

Growth factors and growth factor receptors are considered to be key elements in the pathogenesis of arteriosclerosis and restenosis formation. To study the local expression of epidermal growth factor (EGF) receptor, plaque tissue specimens from advanced lesions (10 coronary, two femoral, seven carotid) of 19 patients were taken for in situ hybridization studies using an EGF-specific cDNA probe. In serial vascular sections of three lesions with increased focal cellularity, autoradiographic silver grains were clearly localized to intimal cells adjacent to the internal elastic lamina. EGF mRNA transcripts were not observed in the fibrous cap, the plaque shoulders, necrotic intimal areas, or in the media. In smooth muscle cells (SMCs) cultured from human plaque tissue, EGF increased SMC proliferative activity in a dose-dependent manner (ED50: 3-6 ng of EGF/ml). Proliferative responsiveness to EGF (10 ng/ml) was found to be significantly (p < 0.01) enhanced in coronary SMCs derived from restenotic lesions as compared to those from primary stenoses. The expression of EGF receptor mRNA in human atheromatous lesions could be of prognostic value to predict an increased SMC proliferative response to stimulatory growth factors.

Arteriosclerosis↗
PubMed1992

[Transcutaneous oxygen pressure in the foot in treadmill stress before and after percutaneous atherectomy].

Transcutaneous oxygen pressure (tcPO2) on the dorsum of the foot and Doppler ankle/arm pressure ratio (AAR) were measured in nine patients with peripheral arterial occlusive disease (PAOD)-stage IIb-III during treadmill exercise before and after (two days and one month) atherectomy. These parameters were compared with nine normal controls and nine PAOD I-IIa patients without atherectomy. All patients with atherectomy showed an increase in their pain free walking distance, and, both two days and one month after the intervention, a significant (p less than 0.05) increase in their exercise/rest tcPO2 ratio (pre-atherectomy: 25% (12-81), two days after: 78% (49-92), one month after: 85% (81-92). AAR displays a significant increase only between pre- and two days after atherectomy, without further significant improvement after one month. We conclude that tcPO2 measurement is an adequate measurement for follow-up studies in patients with PAOD after invasive therapeutic interventions. Furthermore, these data suggest that, while the maximum improvement for the macrocirculation (AAR) occurs shortly after atherectomy, improvement of the microcirculation (tcPO2) is delayed for a prolonged period after revascularization of major arteries, possibly due to reperfusion injury.

Adult↗
PubMed1992

[Growth-inhibiting effect of colchicine on cultured vascular wall myocytes from arteriosclerotic lesions].

Proliferative, migratory, and secretory activities of vascular smooth muscle cells are currently discussed as determinants of human plaque and restenosis formation. Affecting these determinants with drugs may promise anti-arteriosclerotic effects. Plaque tissue was removed from both coronary and peripheral lesions of a total of 18 patients to cultivate smooth muscle cells (SMC) for subsequent in vitro studies. The antitubulin colchicine (C) caused a concentration-dependent decrease of SMC proliferative activity with an IC50 of 5 x 10(-9) M. Migratory activity was analyzed by a standardized semi-automatic video system. This parameter was reduced by C in a concentration-dependent manner (IC50: 5 x 10(-10) M). As shown by immunofluorescence microscopy, the typical structure of microtubules of C-treated SMCs was distorted, whereas the pattern of alpha-actin filaments remained unaltered. Transmission electron microscopy (TEM) revealed that the number of microtubules was diminished after addition of C, and that a distinct disorganization of cytoplasmic organelles as well as the formation of vacuoles had occurred. In vitro studies of human smooth muscle cells derived from vascular plaques indicate that colchicine may be useful as an anti-arteriosclerotic drug, since a concentration-dependent concordant effect on proliferation, migration, and secretory processes of the SMC could be demonstrated.

Aged↗
PubMed1991

[Percutaneous peripheral atherectomy in arterial occlusive disease. Angiographic and clinical acute and long-term results].

130 arteriosclerotic lesions--10 in the iliac, 109 in the superficial femoral, 10 in the popliteal and 1 in the anterior tibial artery--were treated by percutaneous atherectomy in 80 patients (62 men and 18 women: mean age 65 +/- 10 years). 23 of the lesions were concentric, 65 eccentric stenoses, while 42 were fully occlusive. 32 patients were in stage IIb (after Fontaine), 24 in stage IIa and 12 each in stage III or IV. Most of the stenoses were not suitable for conventional balloon dilatation because of their primary morphology. A good early angiographic result (residual stenosis less than 50%) was achieved in 94% of lesions. Mean stenosis degree was reduced from 85 +/- 12% to 12 +/- 10% (occlusions from 100% to 9 +/- 9%). The Doppler index increased from 0.6 +/- 0.18 to 0.85 +/- 0.15 (P less than 0.01). Follow-up angiography after 6 months in 104 lesions demonstrated an average stenosis degree of 33 +/- 25% (occlusions 44 +/- 28%). 26 of the 104 re-studied lesions fulfilled the criterion for re-stenosis (greater than 50%): six concentric ones and five eccentric ones, as well as 15 occlusions. These findings indicate that peripheral atherectomy can be employed with good short and long-term results even in morphologically unfavourable, markedly eccentric or calcified lesions and occlusions.

Acute Disease↗
PubMed1991

[24-hour blood pressure profile: reproducibility of automatic ambulatory measurement].

Twelve patients (8 males, 4 females; mean age 53 [43-60] years) who were undergoing rehabilitation treatment after myocardial infarction were studied to ascertain the reproducibility of ambulatory automatic blood pressure measurements. All were in the last stage of a rehabilitation programme (tolerance to ordinary activity; symptom-free exercise at 75 W). Within two weeks 2, 3 or 4 blood-pressure profiles over 24 hours (total of 32 readings) were obtained by automatic measurement and the records and mean values were compared. Single mild stresses, such as gymnastic exercise or visit to the doctor, were identifiable on the records, but did not alter the overall profile or mean values. Normotensives, hypertensives and borderline hypertensives had 24-hour profiles which were nearly identical with regard to the curve "envelope", day-night profile and mean values in the individual patients. Mean values of diastolic and systolic pressures day by day in each patient showed no deviations greater than 5 mm Hg. Therapeutic measures were recognizable by parallel fall of the curve "envelope", as well as by a reduction in mean value.--At least in these selected patients a single 24-hour profile would in principle have sufficed to describe blood pressure behaviour.

Adult↗
PubMed1991

Role of angioscopy in the treatment of peripheral vascular disease with percutaneous atherectomy.

The role of adjunctive video angioscopy was evaluated in 43 patients with symptomatic peripheral vascular disease undergoing percutaneous atherectomy with the Simpson atherocath. There were 57 target lesions (superficial femoral, n = 46; popliteal, n = 11) of which 33 were stenotic (86 +/- 11%) and 24 were total occlusions of 0.5 to 10.6 cm in length, determined by angiography. Intraluminal inspection, with angioscopes of 0.85 to 1.5 mm in outer diameter housed within a guide catheter, could be performed in 55 of 57 lesions (96%) before atherectomy and in 39 of these 55 (71%) after atherectomy. Failure to obtain an adequate image was usually due to insufficient irrigation, especially in recanalized vessels. In 13 of 23 successfully recanalized arteries (54%) the occlusion could be crossed by the angioscope itself, whereas in 10 cases (42%) a guidewire or a sheath introducer was necessary. Angioscopic passage revealed that often long total occlusions, determined by angiography, consisted of greater than or equal to 1 discrete occlusion with interposed patent thrombus-free vascular segments. After atherectomy, in 15 instances with an acceptable angiographic result, angioscopy was helpful in identifying residual plaques and flaps which then selectively underwent atherectomy. In conclusion, angioscopy proved to be a useful adjunct to angiography in optimizing vascular recanalization with percutaneous atherectomy.

Adult↗
PubMed1991

[Therapy of mild to moderate hypertension. Efficacy and tolerance of Amlodipine in comparison with the combination nifedipine/mefruside].

Earlier clinical trials demonstrated the anti-hypertensive effect of amlodipine, a new calcium channel blocker of the dihydropyridine type. In the present comparative study, we investigated the anti-hypertensive effect of amlodipine in comparison with a combination of nifedipine and mefruside. In both groups, the anti-hypertensive effect was comparable. Normalization of the supine diastolic blood pressure was observed in 72.3% of patients treated with amlodipine and in 66.6% of those patients in the combination group. Both drugs were generally well tolerated, with a somewhat higher incidence of side effects being observed in the combination group. The study shows that amlodipine monotherapy in mild-to-moderate hypertension is equally as effective as combination therapy with nifedipine/mefruside, with amlodipine being superior in terms of tolerability.

Adult↗
PubMed1991

Effects of different once-a-day medications on 24-hour blood pressure recordings in hypertensives.

Compliance with antihypertensive treatment can be increased by using medications that are taken only once daily. There is, however, concern as to whether the efficacy of such drugs is sufficient to cover 24 h. Ambulatory blood pressure monitoring (ABPM) is an ideal technique to assess the effect of this kind of drug and to determine over- or undertreatment. In this study three drugs were examined as once-a-day preparations. Thirty-six patients were treated with three different doses of bisoprolol, as an example of the beta 1-selective beta-blockers; 12 patients were treated with a combination of the AChE-inhibitor enalapril and hydrochlorothiazide; eight patients were treated with nifedipine once per day, a new galenic form of nifedipine, as an example of the calcium-channel blockers. In each group we saw a significant downward shift over the entire 24-h curve. Our results also show that using 24-h blood pressure monitoring devices can help establish an appropriate dose, avoid over- and undertreatment, and control the total burden of the patient.

Adult↗
PubMed1991

[The migration behavior of human vascular myocytes in culture--the screening potential of anti-arteriosclerosis active endogenous and exogenous substances].

Besides proliferation, migration of smooth muscle cells (SMC) is considered to be an essential cellular mechanism involved in plaque formation. Human SMCs were cultured from 14 arteriosclerotic lesions of coronary (n = 5), femoral (n = 7) and aortic (n = 2) arteries. By a semi-automatic standardized video analysis system SMC migratory activity was quantified to be 21.7 +/- 2.1 microns/h (n = 14; x +/- SD). Addition of drugs, such as calcium antagonists (10(-5) - 10(-7) M), heparin (100 micrograms/ml), SIN-1 (10(-5) M) and colchicine (10(-7) M) resulted in a significant decrease of SMC migratory velocity. Exposure to endogenous extracellular matrix proteins (5 micrograms/cm2) showed no effect for collagen I and a significant reduction of SMC migratory activity for fibronectin, respectively. Our results indicate SMC migratory velocity to be a parameter of potential interest to screen various substances for an anti-arteriosclerotic effect.

Arteriosclerosis↗
PubMed1991

[Current status of directional coronary atherectomy in interventional cardiology].

Directional coronary atherectomy (DCA) was used in 74 patients with an average age of 56 years. They were categorized into three different groups depending on the indications for atherectomy. Group I included all patients who had atherectomy as their primary intervention (n = 26), because they were assumed to be unsuitable for PTCA. Group II consisted of patients in whom DCA was used after failed balloon dilatation with unsuccessful but uneventful treatment (n = 20). Group III (n = 28) included cases where DCA was performed as a "rescue" or "bail-out" procedure after failed PTCA resulted in critical ischemia (ECG changes, chest pain, hypotension, and shock). The target lesions were located in LM 2, LAD 52, RCA 16, ACVB 4. The mean length of lesion was 8 mm (2-25 mm). The overall success rate was 94%. The mean stenosis was reduced from 90.6 +/- 10% to 17.2 +/- 14.8% in cases with primary success. The presently available follow-up angiography (n = 31) showed six restenoses. Major complications occurred in seven cases (death: 0, myocardial infarction: 2, CABG within 24 h: 5). Histological analysis revealed highly cellular areal as a major characteristics of a coronary lesion and also of restenotic tissue. Tissue of the lamina elastica was present in 44% and of media in 14%. Thrombus was found only rarely. Ultrastructure showed a significant amount of extracellular matrix in the primary coronary lesions and isolated smooth muscle cells without gap-junctions. RER, mitochondria were typical for the synthesizing type of smooth muscle cell. In restenotic tissue a focal high density of smooth muscle cells with increased synthesizing activity and gap-junctions was present. Endothelial cells (and macrophages) were found only rarely. Furthermore, altered smooth muscle cells from restenotic tissue showed a significantly increased migration and proliferation. Our results show that DCA is a safe and effective technique that can extend the use of percutaneous procedures and provide a promising, nonsurgical option in cases of failed PTCA. Histological analysis revealed a proliferative process as a characteristics of restenosis development.

Angioplasty, Balloon, Coronary↗