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Biomedical subjects

U Dietz

Publications and source records attributed to U Dietz.

At least 19 recordsLinked to original sources
PubMed2005

Shortening the stent length reduces restenosis with bare metal stents: matched pair comparison of short stenting and conventional stenting.

OBJECTIVE: To investigate the effect of reducing stent length on the rate of target lesion restenosis. DESIGN: In a prospective investigation, acute and long term results of a short stenting procedure were analysed by quantitative angiography and compared with results of a conventional stenting procedure selected according to a matched pairs analysis. PATIENTS: Short stents were implanted in 400 consecutive patients with 464 lesions and conventional stents in 430 patients. Demographic and lesion characteristics were comparable between groups. INTERVENTIONS: In short stenting, the shortest stent length to cover only segments with > 30% reduction in vessel diameter was used. In conventional stenting, full coverage of a stenotic vessel segment was intended. MAIN OUTCOME MEASURES: The mean stent lengths of the short stent group (9.8 (4) mm) and the conventional stent group (16.3 (7) mm) differed significantly (p < 0.0001); all other procedural and angiographic parameters were the same. Procedural success was similar for both groups. Control angiography after six months was conducted in 92% of patients. RESULTS: Short stenting resulted in both less restenosis (68 of 431 (15.8%)) than conventional stenting (93 of 381 (24.4%), p = 0.007) and less late lumen loss (0.6 (0.6) mm v 0.75 (0.5) mm, p = 0.0001). Residual stenosis (< 45%) in adjacent vessel segments after short stenting did not affect the restenosis rate. Only the implantation of a < or = 9 mm stent predicted the absence of restenosis in a multivariate analysis. CONCLUSION: Shortening the length of bare metal stents reduces the restenosis rate as compared with conventional stenting.

Angina Pectoris↗
PubMed2004

[Investigation of diabetic men with erectile dysfunction to determine coronary flow reserve (CFR) and cardiac risk under medication with sildenafil (Viagra)].

PURPOSE: Since Sildenafil (Viagra) has become available, there have been reports of death and cardiac risks associated with its use. As large doses of Sildenafil medication is often prescribed particularly in diabetic patients with erectile dysfunction (ED), our study was designed to evaluate the coronary flow reserve (CFR) and possible resulting cardiac risk specifically in diabetic men. MATERIALS AND METHODS: Because these men often suffer from clinically significant ischaemic heart problems without their knowledge and without symptoms, all of our patients were examined by treadmill ECG and CFR. RESULTS: In 44 men (35 - 74 years) with type I and II diabetes also suffering from ED objectified by FCDS measurement of the penile vessels, a surprisingly high rate of objective cardiac problems were found, which were then verified by coronary angiography. These patients are at risk for ischaemic problems during Sildenafil-assisted intercourse and were excluded from further study. Interestingly, only 3 of theses 11 men would have been detected by conventional examinations. Patients free of coronary stenosis who received 50 mg Sildenafil (20 patients) showed no cardiac problems during treadmill exercise and CFR measurement. CONCLUSIONS: Coronary flow reserve in diabetic men lies at the lower end of the normal range, but is not further decreased by Sildenafil. However, diabetics with ED frequently showed coronary artery stenosis that was not clinically symptomatic. Furthermore, conventional cardiological examinations often fail to detect these patients, although they are at ischaemic risk during medically assisted intercourse. Furthermore, although 5 of 20 men who received Sildenafil had an increase in penile blood flow without sexual stimulation, only 7 of 20 were responders to Sildenafil after take home medication. Thus, Sildenafil medication is not a suitable test medication for organic erectile dysfunction.

Adult↗
PubMed2003

[Sildenafil does not change coronary flow reserve in diabetics with erectile dysfunction].

BACKGROUND AND AIM OF STUDY: Disturbance of the microvascular coronary circuit is common in diabetics with erectile dysfunction. We investigated effects of sildenafil on coronary flow reserve (CFR) of the left anterior descending branch. PATIENTS AND METHODS: 43 diabetics (aged 59 +/- 7 years) with erectile dysfunction and without symptoms of coronary artery disease were selected. Cardiac diagnosis, including stress ECG and echocardiography was performed in all. Because of the clinical suspicion of coronary artery disease coronary angiography was performed in 16 of them. Severe coronary artery disease was confirmed in 12 patients who were excluded from further analyses as well as 10 diabetics in whom coronary flow measurements were not possible. In the other 21 diabetics, adenosine-mediated CFR was calculated at baseline and 1 hour after ingestion of 50 mg sildenafil by transthoracic Doppler echocardiography. RESULTS: CFR at baseline was at the lower level of the normal range in 17/21 diabetics (median 245 %, range 210 - 490 %). CFR decreased insignificantly in 12/21 patients after sildenafil administration (Delta CFR -10 %, p = 0.3). Patients with a body mass index > 25 kg/m(2), and left ventricular hypertrophy had the highest reduction of CFR after sildenafil, but a drop of the CFR below 200 % was not observed in any patient. Systemic blood pressure dropped significantly from 130/80 mmHg to 120/72 mmHg (p < 0.002). CONCLUSION: Diabetics with erectile dysfunction often have a CFR in the lower range of normal. Sildenafil did not further reduce CFR. Asymptomatic, severe coronary artery disease often can be found in diabetics with erectile dysfunction. Cardiological screening for contraindications for sildenafil seems mandatory in diabetics with a high cardiovascular risk profile.

Adult↗
PubMed2002

[Percutaneous revascularization of multivessel coronary disease using stents - a multicenter, prospective study].

BACKGROUND AND OBJECTIVE: Symptomatic patients with multivessel coronary disease (MVD) benefit from both coronary artery bypass grafting (CABG) and percutaneous coronary angioplasty (PTCA). The >>German Angioplasty Bypass Investigation<< (GABI-I) trial randomized patients to one of these treatment strategies between 1986 and 1991. In order to evaluate the impact of current technology, in particular coronary stents, the GABI-II trial was initiated, which in 1996 and 1997 prospectively enrolled patients according to the initial GABI-I criteria. PATIENTS AND METHODS: Into the study 136 consecutive patients (108 men, 28 women; 63 +/- 12 years) were included. Patients from GABI-I served as controls. RESULTS: A mean of 2.1 +/- 0.5 vessels were treated per patient (vs. 1.9 +/- 0.5 vessels in the PTCA arm of GABI-I) and 63 % of the lesions were covered with stents. With respect to the primary endpoint less patients remained with a CCS class III or IV in GABI-II after 12 months (1,5 % vs. 8 % in the PTCA arm of GABI-I, p<0,01). No patient required emergency or urgent bypass operation in GABI-II (vs. 9 % in GABI-I, p < 0.01). After 12 months, 8 % of the patients were sent for bypass surgery (CABG) vs. 21 % in GABI-I (p < 0.001), and 20 % (vs. 23 % in GABI-I) of the patients underwent Re-PTCA. The percentage of patients without reinterventions was 72 % vs. 56 % in GABI-I (p < 0.01), but remained lower compared to patients randomized to CABG in GABI-I (94 %, p < 0.001). CONCLUSION: PTCA in patients with MVD is still associated with a higher reintervention rate as compared with CABG. However, in contrast to angioplasty a decade ago, PTCA in conjunction with stents significantly lowered the need for subsequent revascularization, which was mainly driven by the reduced necessity for bypass surgery.

Aged↗
PubMed2002

[Clinical application--suture materials].

The surgical suture should be chosen in dependence of the tissue being operated upon and be oriented on the main properties of its chemical composition. Synthetic absorbable suture materials are the first choice in the majority of the procedures, to prevent the formation of foreign body reaction--excepting sites subjected to continuous mechanical stress, for example hernias, orthopedic and vascular surgery. By causing lesser tissue damage and interfilament bacterial transport, monofilament sutures are preferable than multifilament ones. However, knotting monofilament sutures requires additional skills in comparison to multifilament strains, due to their special handling an knotting properties.

Humans↗
PubMed2001

Angiographic analysis of immediate and long-term results of PTCR vs. PTCA in complex lesions (COBRA study).

We conducted a prospective, randomized trial to compare immediate and long-term effects of percutaneous transluminal coronary angioplasty (PTCA) and high-frequency rotational atherectomy (PTCR) in patients with angiographically predefined complex coronary artery lesions (AHA type B2 and C). The relation of lesion characteristics to procedural results is reported in this angiographic analysis. Patients were randomly assigned to balloon angioplasty (n = 250 patients) or rotational atherectomy (n = 252 patients). Quantitative coronary angiography could be performed in 447 patients to evaluate immediate results and in 293 patients with a 6-month angiographic follow-up. Procedural success was comparable in the PTCR and in the PTCA group (80% vs. 76%, P = 0.260). The need for stent implantation due to a residual stenosis >50% or a bail-out situation was significantly higher in the PTCA group (9.7% vs. 2.0%, P = 0.001). In both treatment groups, diameter stenosis was effectively reduced and MLD increased. The acute gain did not differ between the two groups. At 6-month control, the restenosis rate was comparable in the PTCR and in the PTCA group (37% vs. 35%, P = 0.658), whereas diameter stenosis was significantly more severe in the PTCR group than in the PTCA group (52% vs. 46%, P = 0.039) and, correspondingly, the MLD was significantly smaller in the PTCR group (1.29 mm vs. 1.44 mm, P = 0.031). Late loss was about the same in both groups, however, net gain and net gain index were significantly higher in the PTCA group (0.82 mm vs. 0.64 mm, P = 0.008; and 31% vs. 24%, P = 0.009). Analysis of procedural results for various lesion characteristics revealed no significant difference between treatment groups. In this randomized trial, complex coronary artery lesions were treated with comparable results for angiographic and procedural success and the restenosis rate by both, PTCA and PTCR. Late loss, however, was significantly higher and net gain significantly smaller after PTCR. Stents, although infrequently used, had a relevant impact on immediate PTCA results but not on late results. Cathet Cardiovasc Intervent 2001;53:359-367.

Aged↗
PubMed2000

A randomized comparison of balloon angioplasty versus rotational atherectomy in complex coronary lesions (COBRA study).

AIMS: Rotablation is a widely used technique for the treatment of complex coronary artery lesions but is so far only poorly supported by controlled studies. The Comparison of Balloon-Angioplasty versus Rotational Atherectomy study (COBRA) is a multicentre, prospective, randomized trial to compare short- and long-term effects of percutaneous transluminal coronary angioplasty (PTCA) and rotablation in patients with angiographically pre-defined complex coronary artery lesions. METHODS AND RESULTS: At seven clinical sites 502 patients with pre-defined complex coronary artery lesions were assigned to either PTCA (n=250) or rotablation (n=252). Primary end-points were procedural success, 6-month restenosis rates in the treated segments, and major cardiac events during follow-up. Procedural success was achieved in 78% (PTCA), and 85% (rotablation) (P=0.038) of cases. Crossover from PTCA to rotablation was 4% and 10% vice versa (P=0.019). There was no difference between PTCA and rotablation with respect to procedure-related complications such as Q wave infarctions (2.4% each), emergency bypass surgery (1.2% versus 2.4%), and death (1.6% versus 0.4%). However, more stents were required after PTCA (14.9% versus 6.4%, P<0.002), predominantly for bailout or unsatisfactory results. Including bail-out stents as an end-point, the procedural success rates were 73% for angioplasty and 84% for rotablation (P=0.006). At 6 months, symptomatic outcome, target vessel reinterventions and restenosis rates (PTCA 51% versus rotablation 49%, P=0.33) were not different. CONCLUSION: Complex coronary artery lesions can be treated with a high level of success and low complication rates either by PTCA with adjunctive stenting or rotablation. The long-term clinical and angiographic outcome is comparable.

Adult↗
PubMed2000

Temperature-controlled high frequency ablation for creation of transmyocardial channels: in vivo validation of a novel method.

OBJECTIVE: We investigated the feasibility and short-term effects of a novel procedure to create intramyocardial channels by means of high frequency (HF) ablation in a rabbit in vivo model. METHODS: A flexible catheter ending in a cylindrical electrode (diameter 0.7 mm) with a sharpened tip was used for HF energy application following transmyocardial insertion. Power-controlled or energy-controlled energy applications were performed in 16 anesthetized rabbits after thoracotomy with a follow-up for 3 h. Assessment of myocardial channels and the necrotic zone was performed by morphometric quantification in serial sections. The ferret diameter was used to compare channel dimensions and the extent of necrosis. RESULTS: Thirty-nine power-controlled and 54 temperature-controlled HF applications were performed. The shape of identified channels was round in 71% and 69% had a lumen patency of > or =2/3 of the channel. Ferret diameter of the channels was 414 +/- 180 microm and of the necrotic zone 3,558 +/- 1,200 microm. In temperature-controlled applications, channel dimensions were strongly influenced by the maximum tissue temperature and the duration of energy delivery (T(max): p = 0.0006; duration: p = 0. 003). Channel and necrosis dimensions correlated better with biometric parameters in temperature-controlled compared with power-controlled applications. CONCLUSION: Mechanically created transmyocardial channels can be stabilized by HF heating of the surrounding tissue. A high percentage of these channels remain patent. The channel dimensions are closely correlated with maximum temperature and duration of energy delivery in a temperature-controlled application mode.

Animals↗
PubMed1998

Impact of routine angiographic follow-up after angioplasty.

BACKGROUND: There is an ongoing controversy as to whether repeat coronary angiography should be routinely performed after successful percutaneous transluminal coronary angioplasty (PTCA). METHODS: We examined the 10-year outcome in 400 patients who had or had not undergone an angiographic control 6 months after successful PTCA and a subsequent event-free 6-month period. Our comparison was based on data gathered by questionnaire and telephone interview in 315 patients with (group A) and 85 patients without (group B) a routine 6-month angiographic control. Multivariate analysis (Cox model) was performed to identify predictors of adverse events. RESULTS: During the 10-year follow-up period, 22 (7%) of the 315 patients in group A died, compared with 16 (19%) patients in group B (P= .003). In groups A and B, respectively, acute myocardial infarction occurred in 28 (9%) and 10 (12%) patients (not significant [NS]); coronary artery bypass grafting (CABG) was performed in 42 (13%) and 14 (16%) patients (NS); repeat PTCA was performed in 89 (28%) and 11 (13%) patients (P= .012); and serious adverse events (death, myocardial infarction, CABG) occurred in 76 (24%) and 32 (38%) patients (P= .02). Absence of a 6-month angiographic follow-up was identified as an independent predictor of death associated with a 2.7 times higher mortality rate during the 10-year follow-up period. Previous myocardial infarction increased the risk of death 2.5 times. Any increase of residual diameter stenosis by 10% was combined with a 1.4 times higher mortality rate. The chance of bypass surgery was higher in patients with multivessel disease (2.9 times), in patients with unstable angina (2.1 times), and in case of an increase of residual diameter stenosis by 10% (1.3 times). No predictor for the risk of myocardial infarction was found. Angiographic follow-up increased the likelihood of PTCA 2.5 times. CONCLUSIONS: A routinely performed angiographic control 6 months after successful PTCA is associated with a significantly higher rate of repeat PTCA but, most important, is correlated with a significantly lower mortality rate during the 10-year follow-up period.

Adult↗
PubMed1997

[Effect of qualitative stenosis characteristics on the quality of measurements of various QCA systems].

Reproducibility and accuracy of in vitro measurements are very high using recently developed QCA systems. We analyzed the impact of lesion characteristics ad the image quality on the quality of measurements under clinical conditions. For the study we selected 57 coronary artery lesions which had a clinically relevant distribution for stenosis severity, lesion characteristics, and image quality. Every effort was made to eliminate procedural sources of error. Three investigators measured each lesion five times with each of three QCA systems (AWOS, Cardio and CMS). Only the measurements of the minimal stenosis diameter were analyzed. The precision of all the measurements was high with the AWOS (0.04 mm), the Cardio (0.05 mm), and the CMS systems (0.06 mm). Variability of measurements increased for the following criteria: Ambrose-III morphology (CMS 0.082 mm), surface irregularities (Cardio 0.069 mm, CMS 0.073 mm), TIMI I (Cardio 0.084 mm, CMS 0.0121 mm), and moderate image quality (CMS 0.07 mm). There were no differences in the precision of the measurements in the other groups of lesion characteristics. There were no relevant differences in any of the measurements between the systems (AWOS-Cardio -0.07 mm, AWOS-CMS-0.11 mm, Cardio-CMS-0.04 mm). Smaller diameters were measured with the AWOS system than with the CMS and the Cardio systems when the lesion was calcified (AWOS-Cardio-0.109 mm, AWOS-CMS-0.161 mm). This was only a trend, however, and did not reach statistical significance, which was also true for the other differences found between the systems according to various lesion characteristics. In summary, we found that the measurement quality of the QCA systems used in this study is not altered by the underlying lesion characteristics or the image quality.

Coronary Angiography↗
PubMed1997

Comparison of QCA systems.

AIMS: Excellent agreement between different 'second generation' systems for quantitative coronary arteriography (QCA) has been found in in vitro measurements. To verify the quality and stability of QCA when used in clinical practice, three QCA systems (AWOS, Cardio, and CMS) were used in a representative set of coronary artery lesions. METHODS AND RESULTS: This set consisted of angiographic stenosis images of 57 patients which varied in stenosis severity and morphology. The process of image acquisition, calibration, and measurement was strictly standardized to eliminate procedural sources of error. Three observers performed QCA five times in each lesion with each QCA system. Interobserver variability was low (Dnorm 0.01-0.05 mm, Dmin 0.01-0.02 mm, %stenosis 0.3-0.7%). Values of system precision were excellent (Dnorm 0.11-0.13 mm, Dmin 0.04-0.06 mm, %stenosis 2.1-2.6%). Comparison of measurements between three QCA systems revealed good agreement (range of mean differences for Dnorm 0.03-0.12 mm, Dmin 0.04-0.11 mm, and %stenosis 0.5-3.6%) and high correlation (corr 0.902-0.977). There was a tendency to measure smaller values for Dmin and consequently to identify more severe stenoses with the AWOS system than with the Cardio and CMS systems. All QCA results were compared to measurements done with the Brown Dodge method to reveal failure of the QCA measurements. These results showed excellent agreement without any systematic deviation (mean differences for Dnorm 0.01-0.08 mm, Dmin 0.02-0.06 mm, and %stenosis 1.3-1.8%). None of the differences were statistically significant. CONCLUSION: We therefore conclude that using the defined version of the AWOS, Cardio, and CMS systems, there is no difference in precision or accuracy when used for QCA of coronary artery lesions.

Algorithms↗
PubMed1997

[Dynamic 31-phosphorus magnetic resonance spectroscopy of the m. quadriceps: therapy-induced changes in arterial occlusive disease].

PURPOSE: The present investigation aimed at examining changes in muscle metabolism caused by treatment of arterial occlusive disease, using dynamic 31-phosphorus methods. METHOD: 32 patients with arterial occlusive disease were examined in a 1.5 T apparatus with a 6 cm surface coil before and after treatment. The metabolic changes in the quadriceps muscles were visualised during a 36 s phosphorus spectrum during rest, exercise (isometric and isotonic) and during a period of recovery. RESULTS: Vascular therapy resulted in a significant increase in the duration of both types of exercise during dynamic phosphorus spectroscopy (isometric exercise: 282 s against 199 s: p = 0.002, isotonic exercise: 575 s against 222 s; p = 5 x 10(-6). After treatment, exercise-induced changes in pH (7.00 against 6.94; p = 0.004 and 7.00 against 6.93; p = 0.02) and the ratio Pi/PCr (0.34 against 0.44; p = 0.002 and 0.36 against 0.50; p = 0.009) were significantly smaller than before therapy, using a similar amount of exercise. Recovery time of Pi/PCr (45 s against 82 s; P = 10(-5) and 42 s against 57 s; p = 0.01) and pH value (154 s against 181 s; p = 0.14 and 173 s against 214 s; p = 0.22) showed significant reduction after treatment. CONCLUSIONS: Dynamic 31-phosphorus magnetic resonance spectroscopy indicates increased mitochondrial oxidative capacity in the quadriceps muscles as evidence for increased oxygen supply to muscle tissue following vascular therapy.

Arterial Occlusive Diseases↗
PubMed1996

Angiographic follow-up results of a randomized study on angioplasty versus bypass surgery (GABI trial). GABI Study Group.

Although several randomized trials have been performed to compare the outcomes of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass surgery (CABG) in patients with multivessel disease, there is little data available on angiographic follow-up results. The present substudy of the German angioplasty versus bypass surgery investigation (GABI Trial) compares the angiographic revascularization status in these two cases 6 months after treatment. Follow-up angiograms were available in 102 CABG patients and 117 PTCA patients. Although the protocol excluded patients with total occlusion, on follow-up 6 months after treatment we found total occlusion of 94 native arteries (36.9%) in the CABG group and of six arteries (2.5%) in the PTCA group (P < 0.001). The rate of occluded native vessels did not correlate significantly with the severity of the lesion before bypass surgery. In the CABG group 31 bypass grafts (12.2%) were found to be occluded at the 6 month follow-up examination (29/225 vein grafts [12.9%]; 2/30 mammary artery grafts [6.7%]). The main pathway, defined as the nutrient vessel (native vessel or bypass graft) providing the least resistance to blood flow, was narrowed by a lesion with a diameter stenosis of 70-100% for 36 target lesions (14.1%) in the CABG group and 39 target lesions (16.2%) in the PTCA group (P, ns). However, the prevalence of moderately severe lesions with a 50-69% diameter reduction of the main pathway was significantly greater in the PTCA group (44 lesions, 18.3%) than in the CABG group (19 lesions, 7.5%, P < 0.01). Thus, 6 months after randomized allocation to PTCA or CABG, we found comparable rates of high-grade lesions in the main pathways of both treatment groups. Whereas moderately severe lesions of the main pathway were predominantly seen in the PTCA group, there was marked disease progression to total occlusion in the native circulation after bypass grafting.

Aged↗
PubMed1996

[Automatic report documentation in cardiology using a speech recognition system].

Computer systems that can convert spoken text into written text have recently become available. In one such system, the phonetics of spoken words are compared with those of 32 000 stored words, with a statistical program helping to choose the word with the highest probability of being correct. We evaluated the practicability of the IBM Voice Type system for writing medical reports using a cardiologic vocabulary. A total of 200 medical documents were generated with a mean of 301 +/- 52 words. In the mean, 12 +/- 5 words were falsely recognized in each document, resulting in a rate of correct recognition of 95.1 +/- 2.5%. It is possible to correct a falsely recognized word by choosing an alternative word from a provided list, which worked in our case in 51% (6.1 +/- 2.8 words in each document). Correction of falsely recognized words had to be done by manual input 49% of the time (5.9 +/- 2.9 words in each document). The mean time demand for word correction amounted to 57 +/- 15 s for each document, whereas correction by manual input needed more time (37 +/- 14 s) than choosing from a list of alternative words (20 +/- 4s). A requirement for use of the Voice Type system is a reduced speech rate. Dictation of our documents took on average 260 s when done with a normal speech rate, and 400 s when done at a reduced speech rate. In conclusion, automatic writing of cardiologic reports can be done easily and with a low failure rate using the IBM Voice Type system with a cardiologic vocabulary. It takes about 3 min longer to create a medical text 1 1/2 pages long which is free of mistakes by using the Voice Type system than to simply dictate the text. Time can be saved by eliminating the need to check a preliminary report. The major advantage of automated reporting is that the written report is immediately available. For each discipline, specific vocabularies should be validated.

Cardiology↗
PubMed1995

Differential expression of collagen types I, II, III, and X in human osteophytes.

BACKGROUND: Osteophytes are neoplastic cartilaginous and osseous protrusions growing at the margins of osteoarthritic joints. Their formation involves complex patterns of cellular proliferation, differentiation, as well as matrix synthesis and turnover that are poorly understood. EXPERIMENTAL DESIGN: Here we report on an experimental approach using in situ hybridization and immunohistology to elucidate pathways of chrondrocyte differentiation in human osteophytes. Ab and cDNA probes for collagen types were used as specific parameters for chondrocyte phenotypes. RESULTS: In early precartilaginous mesenchymal tissue, cytoplasmic mRNA for alpha 1(I) and alpha 1(III) collagen genes (Col1A1 and Col3A1) were found by in situ hybridization, correlating with the distribution of type I and III collagen as revealed by Ab staining. Strong expression of type II collagen both at mRNA and protein levels was the hallmark of chondrogenic differentiation in the cartilaginous zone of osteophytes. Type II collagen expression increased in all cartilaginous and fibrocartilaginous areas with growth and maturation of osteophytes. The signal intensity obtained after in situ hybridization with a COL2A1 probe was high and corresponded to that obtained in fetal cartilage, whereas normal adult articular cartilage usually did not show measurable type II collagen expression. In fibrocartilaginous areas, the most abundant, but heterogeneous tissue type seen in osteophytes, type II and III collagen mRNA expression overlapped considerably. Type III collagen was scattered, both pericellularly and interterritorially, over the whole osteophyte, excluding bone and chondrocytic cells of the deep zone. The strongest type I collagen expression was seen in bone and in the superficial fibrous layer. In areas of endochondral ossification, large chondrocytes were found expressing type X collagen, a specific marker for hypertrophic chondrocytes. CONCLUSIONS: These results show that discrete stages of cartilage differentiation can be precisely followed in osteophytes using collagen type-specific cDNA probes and Ab as markers. In addition, a fibrocartilaginous chondrocyte phenotype was identified that expresses type II and III, but not type I collagen.

Aged↗
PubMed1994

High-frequency rotational ablation following failed percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) failed in 29 of 1,150 patients (2.5%) after successful passage of the guide wire. The reasons for failure were inability to pass the lesion with a balloon in 28 patients and inability to dilate the lesion in 1 patient. In these patients (15 stenoses and 14 chronic occlusions) rotational ablation was performed. We were able to pass the burr through the lesion in all of them, resulting in a reduction of diameter stenosis from 87 +/- 15 to 51 +/- 18%. Rotational ablation alone was initially successful (stenoses reduction > 20% and residual stenoses < 50%) in 15 of 29 (52%) patients. Additional PTCA was performed in 21 of 29 (72%) patients, in 8 to optimize the initially successful result and in 13 because the outcome was unsatisfactory. After dilatation the diameter stenosis was reduced to 41 +/- 14% immediately after the procedure and to 36 +/- 13% at 24 hr control. Overall success was achieved in 21 of 29 (72%) patients immediately after the procedure and in 26 of 29 (90%) patients at 24 hr control. No acute major complications occurred. We conclude that rotational ablation can be used as a safe and effective alternative when PTCA is not successful.

Angioplasty, Balloon, Coronary↗
PubMed1993

Alterations of collagen mRNA expression during retinoic acid induced chondrocyte modulation: absence of untranslated alpha 1(I) mRNA in hyaline chondrocytes.

Retinoic acid (RA) has been shown to rapidly modulate the collagen expression pattern of chondrocytes in vitro at doses of 1-10 microM. Embryonic chicken sternal chondrocytes stop synthesizing the cartilage-specific type II collagen within 2-4 days of RA treatment and turn on the synthesis of types I and III collagen and fibronectin. While suppression of type II collagen synthesis and onset of type III collagen and fibronectin synthesis have been shown to be regulated at the transcriptional level, conflicting data are available on a possible post-translational regulation of alpha 1(I) collagen gene expression. In this study we demonstrate by comparing a commonly used alpha 1(I) cDNA probe from the 3' end of the alpha 1(I) mRNA with a newly prepared alpha 1(I) cDNA probe from the 5' end (p1E1) that--in contrast to previous reports--chicken sternal chondrocytes do not contain untranslated alpha 1(I) mRNA which may become translatable after RA treatment. By in situ hybridization we show the absence of cytoplasmic alpha 1(I) mRNA from chondrocytes and its presence in the perichondrium of sternal cartilage. Perichondral cells might have contaminated sternal chondrocyte preparations, explaining low levels of alpha 1(I) mRNA seen by Northern hybridization and RNase protection assays of chicken sternal cartilage mRNA even with the p1E1 probe. We show by Northern hybridization and metabolic labeling with 3H-proline followed by SDS-gel electrophoresis that retinoic acid at 3 microM suppresses type II, IX, and X collagen gene expression within 2 days both at the mRNA and protein level and induces the onset of alpha 1(I), alpha 2(I), and alpha 1(III) expression within 3 days. No expression of CRABP, the cellular retinoic acid binding protein, was seen in RA-treated or control chondrocytes, indicating that CRABP protein is not involved in the RA-induced modulation of the chondrocytes.

Animals↗