Biomedical subjects

K Seidl

Publications and source records attributed to K Seidl.

At least 55 records · Page 3Linked to original sources

PubMed1999

Spectrum of reperfusion strategies and factors influencing the use of primary angioplasty in patients with acute myocardial infarction admitted to hospitals with the facilities to perform primary angioplasty. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group.

OBJECTIVE: To determine the frequency of the use of primary angioplasty in patients with acute myocardial infarction and the factors influencing its indications in hospitals with the facilities to perform this treatment. DESIGN: Data from the maximal individual therapy in acute myocardial infarction (MITRA) trial were analysed, concerning the effects of the decisions of individual hospitals, the time of admission of patients, and the effects of patient characteristics on the selection of reperfusion treatment. PATIENTS: Between June 1994 and January 1997 eight hospitals treated 1532 patients with acute myocardial infarction. 418 (27.3%) were treated conservatively, 641 (41.8%) were treated using intravenous thrombolysis, 387 (25.3%) were treated using primary angioplasty, and 86 (5.6%) received a combination of thrombolysis and angioplasty. RESULTS: The proportion of patients treated with primary angioplasty varied from 1.8% to 57.7% among the eight hospitals. The use of primary angioplasty during non-office hours also showed wide variation, ranging from 20% to 54% between centres. The use of thrombolysis was comparatively evenly distributed during the non-office hours, ranging from 50-69%. Four hospitals with a primary angioplasty use rate > 30% showed no difference in the proportion of patients with contraindications for thrombolysis, high risk patients, or a combination of both, when compared with four hospitals with a lower rate of primary angioplasty use (98/322 (30.4%) v 19/65 (29. 2%), respectively, p = 0.847). CONCLUSIONS: In hospitals with the facilities for performing primary angioplasty the most important factors influencing its use were the discretion of the individual hospital and the time of patient admission. Characteristics of patients did not influence the choice of reperfusion treatment

Angioplasty, Balloon, Coronary↗

PubMed1999

Primary angioplasty in acute myocardial infarction: differences between referred patients and those treated in hospitals with on-site facilities?

BACKGROUND: Primary angioplasty for acute myocardial infarction (AMI) can only be performed in a limited number of centers. Therefore, some patients will be referred for this procedure. DESIGN: We analyzed the data of the prospective observational MITRA trial, which took place at 54 hospitals in southwest Germany, to describe current practices and outcomes in referred patients compared to patients treated on-site. RESULTS: Out of 491 patients treated with primary angioplasty, 63 (12.8%) were referred. Out of 46 hospitals without facilities to perform primary angioplasty, 29 (63%) never referred patients. Referred patients were less often male (60.3% versus 75.9%; p = 0.013), suffered more often from anterior wall infarction (62.9% versus 45.8%; p = 0.014), and more often had absolute contraindications against thrombolysis (11.1% versus 2.8%; p = 0.006). In-hospital time to treatment was 80 minutes in patients treated on-site compared to 190 minutes in referred patients (p = 0.001). There was a non-significant difference of in-hospital mortality between the two groups (11.1% for referred versus 7.5% on-site; p = 0.319). Referred patients had a higher hospital morbidity as expressed by a higher proportion of post-infarction angina (28.6% versus 4.2%; p = 0.001), a more frequent need for urgent revascularization (43.8% versus 16.4%; p = 0.001) and a higher proportion of advanced heart failure (11.1% versus 4.4%; p = 0.062). CONCLUSIONS: Referral of patients with AMI for primary angioplasty is used only in a minority of hospitals. The referred patients represent a selected, more ill subgroup, resulting in a higher hospital morbidity compared to patients treated on-site. Continuous efforts should be undertaken to decrease the time delay from admission at the initial hospital to the beginning of revascularization.

Acute Disease↗

PubMed1998

Comparison of metoprolol and sotalol in preventing ventricular tachyarrhythmias after the implantation of a cardioverter/defibrillator.

The purpose of this prospective study was to evaluate, on an intention-to-treat basis, the efficacy of d,l-sotalol and metoprolol with regards to the recurrence of arrhythmic events after implantable cardioverter defibrillator (ICD) implantation. After ICD implantation, 70 patients were randomly assigned to treatment with either metoprolol (mean dosage 104+/-37 mg/day in 35 patients) or d,l-sotalol (mean dosage 242+/-109 mg/day in 35 patients). During follow up ventricular tachycardia (VT), fast VT, and ventricular fibrillation (VF) episodes were calculated. Metoprolol treatment led to a marked reduction in the recurrence of arrhythmic events. Actuarial rates for absence of VT recurrence at 1 and 2 years were significantly higher in the metoprolol group compared with the d,l-sotalol group (83% and 80% vs 57% and 51%, respectively, p=0.016). The actuarial rates for absence of fast VT or VF were 80% in the metoprolol group compared with 46% in the d,l-sotalol group (p=0.002). During a follow up of 26+/-16 months, there were 3 deaths in the metoprolol group compared with 6 deaths in the d,l-sotalol group. Actuarial rates of overall survival were not significantly different in the 2 groups (91% vs 83%, p=0.287). In this prospective, randomized, controlled study the recurrence rate of ventricular tachyarrhythmias in patients treated with metoprolol was lower than in patients treated by d,l-sotolol.

Adolescent↗

PubMed1998

Risk of thromboembolic events in patients with atrial flutter.

Based on multiple studies, clear, guided anticoagulation therapy is recommended for patients with atrial fibrillation. The value of anticoagulation therapy in patients with atrial flutter, however, is less well established. Little is known about the incidence of thromboembolism in patients with atrial flutter. We evaluated the risk of thromboembolism in 191 consecutive unselected patients referred for treatment of atrial flutter. A history of embolic events was noted in 11 patients. Acute embolism (<48 hours) occurred in 4 patients (3 after direct current cardioversion, 1 after catheter ablation). During follow-up of 26+/-18 months, 9 patients experienced thromboembolic events. During the follow-up, the overall embolic event rate (including acute embolism and thromboembolic events during follow-up) was 7 % in this patient population. Risk indicators for an embolic event in an univariate analysis were organic heart disease (p = 0.037), depressed left ventricular function (p = 0.02), history of systemic hypertension (p = 0.004), and diabetes mellitus (p = 0.0038). Using multivariate analysis, a history of hypertension was the only independent predictor for elevated embolic risk in this patient population (odds ratio = 6.5; 95% confidence intervals 1.5 to 45). Thus, the thromboembolic risk is higher than previously recognized for patients with atrial flutter. Anticoagulation therapy may decrease this risk.

Aged↗

PubMed1998

cMeso-1, a novel bHLH transcription factor, is involved in somite formation in chicken embryos.

The segmentation of somites from the paraxial mesoderm is a crucial event in vertebrate embryonic development; however, the mechanisms underlying this process are not well understood. In a yeast two-hybrid screen we have identified the novel basic-helix-loop-helix (bHLH) protein cMeso-1 which is expressed in the presomitic mesoderm of early chicken embryos. Initially the gene is activated in the epiblast and transcripts concentrate later in and around the primitive streak. When the segmental plate is laid down the cMeso-1 expression domain successively retracts toward the caudal end but a second domain appears in bilateral stripes in the anterior paraxial mesoderm. This highly dynamic domain of cMeso-1 transcripts demarcates the area immediately posterior to the next prospective pair of somites in cyclic waves which apparently correspond to the formation of new somites. Loss of cMeso-1 function by antisense RNA or oligonucleotides results in severe attenuation of somitogenesis suggesting that it plays an important role in setting up the segmentation process. The dynamic and periodically reiterated expression of cMeso-1 along the anteroposterior axis is not dependent on anterior structures or the propagation of a signal along the anteroposterior axis but seems to follow an intrinsic patterning program which is already set up in the segmental plate.

Amino Acid Sequence↗

PubMed1998

MyoD and MEF2A mediate activation and repression of the p75NGFR gene during muscle development.

In an effort to clarify transient expression of the NGF low-affinity receptor p75NGFR during muscle development we have focused on the molecular mechanisms involved in the initiation and cessation of p75NGFR gene expression. Using quiescent C3H10T1/2 fibroblast as a tool, we observed that induction of differentiation competence in MyoD-transfected 10T1/2 fibroblasts was accompanied by the initiation of p75NGFR expression. Moreover, we could show that the bHLH transcription factor MyoD itself is a powerful candidate for transcriptional activation of the p75NGFR gene in muscle precursor cells. By means of MyoD-mutants we have found that both the amino terminus of the MyoD molecule as well as the bHLH-region are essential for transcriptional activity on the p75NGFR promoter. The fact that myocyte enhancer factor MEF2A inactivated MyoD-induced p75NGFR promoter activity strongly suggests that cell-specific regulation of the p75NGFR gene might be strictly dependent on the intracellular composition and balance of the appropriate bHLH-transcription factors and their modulators.

Cell Differentiation↗

PubMed1998

Chicken winged-helix transcription factor cFKH-1 prefigures axial and appendicular skeletal structures during chicken embryogenesis.

The cDNA cFKH-1 encodes a chicken winged helix/forkhead domain transcription factor that presents a dynamic expression pattern during chicken embryogenesis. Transcripts accumulate predominantly in early paraxial mesoderm, developing somites, and within mesenchymal precursors of skeletal structures. cFKH-1 RNA is first detected in the developing mesoderm of HH stage 6 embryos. During subsequent development cFKH-1 RNA accumulates in a dorsal domain of the anterior presomitic mesoderm and later in all cells of the epithelial somites before it becomes limited to the sclerotome when somites compartmentalise. cFKH-1 expression persists in the sclerotome, forming the vertebrae and in mesenchymal condensations in limb buds that will give rise later to the appendicular bones. In differentiated chondrocytes and definitive bone structures, however, cFKH-1 expression is down-regulated. Additional expression domains are found in mesenchyme of branchial arches and the head, in the dorsal aorta, and weakly in the endocardium. Based on its expression pattern and the structure of the forkhead DNA-binding domain cFKH-1 constitutes a chicken relative to the murine family of fkh-1/MF1 and MFH-1 factors. The embryonic expression of the cFKH-1 gene defines distinct mesodermal domains and suggests that it may regulate gene expression in mesenchymal cell lineages that will form cartilage in trunk and limb buds.

Amino Acid Sequence↗

PubMed1998

Evidence for the participation of nerve growth factor and its low-affinity receptor (p75NTR) in the regulation of the myogenic program.

We have studied expression and function of neurotrophins and their receptors during myogenic differentiation of C2C12 cells, a clonal cell line derived from mouse muscle that is capable of in vitro differentiation. The genes coding for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and their common low-affinity receptor p75(neurotrophin receptor) (p75NTR) were shown to be expressed in C2C12 myoblasts and downregulated during myogenic differentiation and fusion into myotubes. Cocultures with dorsal root ganglia from day 8 chick embryos revealed neurite-promoting activities of C2C12 cells that ceased with myogenic differentiation. These data suggest a temporal and developmental window for the effect of myogenic cell-derived neurotrophins on neuronal as well as on myogenic cell populations. NGF was shown to increase DNA synthesis and cell growth of C2C12 myoblasts and to enhance myogenic differentiation in this cell line. We present evidence that NGF-mediated processes take place at stages preceding myogenic differentiation. Enhanced muscle differentiation was also seen in p75NTR-overexpressing C2C12 myoblasts which maintained high levels of receptors but ceased to produce NGF during differentiation. In contrast, when exogenous NGF was present at the onset of myogenic differentiation of receptor-overexpressing cells, muscle cell development was strongly repressed. This indicates that downregulation of p75NTR is necessary for guiding myogenic cells towards terminal differentiation. Since none of the trk high-affinity neurotrophin receptors could be demonstrated in C2C12 cells, we conclude that NGF mediates its nonneurotrophic effect via its low-affinity receptor in an autocrine fashion.

Animals↗

PubMed1998

Regulation of nerve growth factor and its low-affinity receptor (p75NTR) during myogenic differentiation.

In our preceding report, we have shown that nerve growth factor (NGF) and its low-affinity receptor (p75NTR) are expressed in C2C12 myoblasts and downregulated during myogenic differentiation. Furthermore, NGF affects myogenic differentiation and cell growth via p75NTR and downregulation of p75NTR is essential for myogenic differentiation (Seidl et al., 1998). Here we show that NGF and p75NTR are regulated by mechanisms preceding terminal differentiation in myogenic cells. These mechanisms include cell-density phenomena such as cell-cell contact as well as signaling of basic fibroblast growth factor (FGF-2) and its receptor (FGFR1). Downregulation of NGF and p75NTR occurred as a consequence of increasing cell density, an important trigger for the onset of myogenic differentiation. FGF-2 and FGFR1 were shown to be present in C2C12 cells and exogenous FGF-2 induced NGF and p75NTR expression, implying that FGF/FGFR signaling is an upstream regulator of the NGF/p75NTR system. The fact that FGF-2 could suspend yet not abolish density-induced downregulation indicates that cell-cell contact counteracts the FGF effect and ultimately terminates NGF/p75NTR signaling. This evidence, together with the observation that p75NTR expression is suppressed in muscle progenitors, which constitutively express adenovirus E1A proteins and thus lack the competence of myogenic differentiation, underline the important role for the NGF/p75NTR system in the interplay of multiple factors and biological systems that balance myogenic differentiation at the appropriate spatial and temporal level.

Adenovirus E1A Proteins↗

PubMed1998

[Incidence of atrial fibrillation in relation to atrial catheter site in two-chamber pacemakers].

INTRODUCTION: This study evaluated the impact of the atrial lead implantation site on the subsequent development of atrial arrhythmias. METHOD: Dual chamber pacemakers were implanted in 109 consecutive patients. The indication was AV-block in 51 patients, sick sinus syndrome in 58 patients. No patient had chronic atrial fibrillation, but 12 patients (11%) had paroxysmal atrial fibrillation before implantation. Patients were classified according to the atrial lead implantation site: right atrial appendage and right atrial free wall. RESULTS: Preimplant episodes of atrial fibrillation were similar in patients with lead implantation at the free wall and with implantation in the right atrial appendix (13% vs 7.5%, P=0.53). During a mean follow-up of 24+/-13 months, new paroxysmal atrial fibrillation occurred in 5% after lead implantation in the appendix vs 28% of patients after implantation at the right atrial free wall (P = 0.004). CONCLUSION: The development of atrial arrhythmias in dual chamber pacing is influenced by the implantation site of the atrial lead. The frequency of atrial arrhythmias during follow-up is higher after atrial lead implantation at the right lateral wall than in the appendix.

Adult↗

PubMed1998

Is the atrial high rate episode diagnostic feature reliable in detecting paroxysmal episodes of atrial tachyarrhythmias?

The atrial high rate episode diagnostic in the Thera pacemaker reports frequency, duration, and date/time of atrial tachyarrhythmias according to programmed criteria. The aim of the study was to validate the atrial high rate episode diagnostic feature. Episodes of atrial fibrillation recorded by Holter monitoring were compared to episodes detected by the pacemaker. Forty five ambulatory (Holter) recordings were used for evaluation. Thirty of 45 ambulatory (Holter) recordings showed sinus rhythm. On 4 of these 30 ambulatory (Holter) recordings, the Thera detected 12 episodes of atrial tachyarrhythmias as false-positives (sinus rhythm was detected as atrial tachyarrhythmia). The main reason was far-field R and T was oversensing. On 15 of 45 ambulatory (Holter) recordings, 125 episodes of atrial tachyarrhythmias were recorded. Ninety-three of these events also were detected by the pacemaker, while for 32 events the Thera reported sinus rhythm. The main reason was that the episodes were of too short duration. Therefore, the Thera (programmed with detection rate 160 beats/min, detection beats 40, termination beats 10) was unable to detect atrial tachycardias. Software simulation of the diagnostic algorithm under several programming settings using the digitized Holter files demonstrated highly reliable detection of atrial tachyarrhythmias (sensitivity 98%, specificity 100%) when programmed as follows: detection rate 220 beats/min, detection beats 10, termination beats 20. It can be concluded that Thera's high rate episode monitor is a reliable tool for detection of atrial tachyarrhythmias, if programmed as recommended.

Aged↗

PubMed1998

Unexpected complete AV block following transcatheter ablation of a left posteroseptal accessory pathway.

Radiofrequency catheter ablation is the procedure of choice for the nonpharmacological treatment of AV connections that are responsible for debilitating tachycardia. This article describes a patient with a manifest left posteroseptal accessory pathway and recurrent syncopes in whom a transient complete AV block occurred after transcatheter radiofrequency ablation of the left posteroseptal pathway. Three electrical abnormalities were present in this patient: AV infra-Hisian block, a left posteroseptal accessory pathway, and an AV nodal reentry tachycardia. This case report reminds you that one should be prepared for all fall backs during catheter ablation.

Atrioventricular Node↗

PubMed1998

Importance of preimplantation procedures in candidates for an implantable atrial defibrillator.

INTRODUCTION: Due to the limited efficacy of antiarrhythmic drugs for the treatment of atrial fibrillation, several nonpharmacologic therapeutic options have been developed. One of these options is an implantable atrial defibrillator for patients with severe symptoms and infrequent drug-refractory episodes of atrial fibrillation. The purposes of this study were: (1) to evaluate how many patients with atrial fibrillation are possible candidates for an implantable atrial defibrillator; and (2) to report the results and findings of preimplantation testing in a single center. METHODS AND RESULTS: From our atrial fibrillation outpatient clinic, we evaluated the number of possible candidates for an atrial defibrillator using the following criteria: (1) recurrent persistent atrial fibrillation; (2) long-lasting but infrequent episodes; (3) refractory to antiarrhythmic drugs; (4) capability of maintaining normal sinus rhythm; and (5) no factors increasing proarrhythmic risk. In those patients eligible for an atrial defibrillator, a separate preimplantation test was performed to evaluate atrial defibrillation limits and patient acceptance. Thirty-one of 196 patients were possible candidates for an atrial defibrillator. Fourteen of these 31 patients agreed to participate in the METRIX clinical study phase I on atrial defibrillators. Six of these patients met implantation criteria; two patients refused permanent implantation because of intolerable pain. Implantation was performed in four patients; however, one patient could not be cardioverted intraoperatively despite a successful preimplantation test. CONCLUSION: About 16% of selected patients with atrial fibrillation are possible candidates for an atrial defibrillator. However, successful preimplantation testing does not exclude implantation failure.

Aged↗

PubMed1997

[Catheter ablation in cardiac arrhythmia. Interventional therapy of symptomatic and threatening arrhythmias of the heart].

Catheter ablation is a curative intervention for the treatment of supraventricular, but also ventricular, tachycardias that has proved both safe and effective. In patients with supraventricular tachycardias in underlying WPW syndrome or nodal tachycardia and appreciable symptoms, catheter ablation can be considered the treatment of choice. But many patients with monomorphic ventricular extrasystole that is difficult to control medically experience considerable subjective impairment in their daily life. It is possible that in such patients, too, catheter ablation may, sometime in the future, be used to cure their condition. However, long-term results must first be awaited.

Aged↗

PubMed1997

[Tricuspid valve endocarditis. Demonstration of a rare disease exemplified with 3 case reports].

BACKGROUND: Endocarditis of the tricuspid valve is a rare form of valvular endocarditis and occurs mainly in patients with special risk factors. CASE REPORTS: The three case reports demonstrate 3 young patients (age 30 to 37 years, 2 female and 1 male) with a typical history of those risk factors. The two women were intravenous drug addicts and one of them had suffered already an episode of tricuspid valve endocarditis several years ago. The man developed his infection after implantation of a pacemaker. In all of the three patients the endocarditis was due to infection with staphylococci twice staphylococcus epidermidis and once staphylococcus aureus. In two of the three patients the endocarditis could not be cured by intravenous antibiotics alone and these patients had to undergo cardiac valvular surgery. All patients left the hospital after several weeks without signs of infection. CONCLUSION: In clinical praxis the introduction of a special endocarditis service, a small team which has to be consulted in every suspected case of endocarditis, seems to be beneficial as well as the use of the Duke criteria for diagnosis in those cases.

AIDS-Related Opportunistic Infections↗

PubMed1997

Pseudoaneurysm after cardiac catheterization: therapeutic interventions and their sequelae: experience in 86 patients.

After diagnostic cardiac catheterization in 8,715 patients, a pseudoaneurysm was diagnosed in 86 (1%) patients. Primary conservative management by repeated compression bandages (CB) or ultrasound guided compression (UGC) was attempted in all patients. Occlusion of the pseudoaneurysm was achieved significantly more often by UGC (41/47; 87%) than by CB (22/39; 56%; P = 0.016). Of 86 patients, 23 (27%) required surgical treatment. Major clinical acute complications occurred after surgery in 8/23 cases (35%) versus 4/63 (6%; P = 0.0004) following successful CB or UGC. However, intention-to-treat analysis showed no difference in the rate of acute complications in the CB or UGC group (15.4% versus 12.8%, P = 0.7272), because of a trend towards a higher complication rate following secondary surgery in the UGC (4/6 = 66.7%), as compared to the CB group (4/17 = 23.5%, P = 0.1589). During follow up, 22/64 (34%) patients reported persistent inguinal complaints, 9/15 (60%) after surgery and 13/49 (27%) after successful CB or UGC (P = 0.0169). However, according to the intention-to-treat analysis, there was no significant difference between the initial groups (CB: 26.1% versus UGC: 39.0%, P = 0.2958). Despite a higher effectiveness of UGC to achieve occlusion of a pseudoaneurysm compared to CB (87% vs. 56%), UGC is not superior to CB because of a higher rate of acute complications as well as long-term complaints in those patients requiring secondary surgery in the UCG group as compared to the CB group.

Adult↗

PubMed1997

[Direct dilatation and emergency bypass operation of main branch occlusion in acute anterior wall infarct and cardiogenic shock].

Occlusion of the left main coronary artery (LMCA) is the cause of myocardial infarction in about 0.04%. Those patients who do not die during the acute phase often do have a dominant right coronary artery with extensive collaterals to the left coronary artery. Because this is a very rare situation there are only some cases reports dealing with the management of these patients. A 60 years old woman was admitted to our hospital with the signs of an acute Q-wave anterior myocardial infarction. Within a few minutes after the arrival she developed a cardiogenic shock. Coronary angiography was performed immediately. The left main coronary artery was occluded and a big right coronary artery showed a significant stenosis. There were many collaterals from the right coronary artery supplying the left coronary artery. After information of the cardiac surgeons, primary angioplasty of the LMCA was performed in order to achieve hemodynamic stabilisation and to relieve symptoms. Reperfusion of the left anterior descendent coronary artery (LAD) could be achieved within 30 minutes. This led to hemodynamic stabilisation of the patient. But a significant residual stenosis of the LMCA remained and the circumflex artery was still occluded. In the meanwhile cardiac surgery was able to be performed and so the patient was transferred to surgery without further dilatation or stent implantation. Four venous grafts (LAD, first diagonal branch, circumflex artery and right coronary artery) were inserted. After 4 weeks the patient was in a good shape and could be discharged at home. Primary angioplasty seems to be an effective treatment in patients with acute myocardial infarction and an occlusion of the LMCA. But coronary bypass surgery is nearly almost necessary during the following period in order to achieve complete revascularisation and to improve survival.

Angioplasty, Balloon, Coronary↗

PubMed1997

[Problems in carrying out baroreflex sensitivity measurements in clinical routine practice: practicability and complications].

Measurement of baroreflex sensitivity is a new method to identify patients after myocardial infarction with a high risk for sudden cardiac death, ventricular tachycardia or ventricular fibrillation. In this retrospective study the baroreflex sensitivity was obtained noninvasively by measuring the systolic blood pressure blood pressure with a FINAPRES-device and correlating this with the R-R intervals of the ECG after raising blood pressure with an intravenous dose of Norfenefrin-hydrochloride (Novadral). According to other investigators a correlation of > 0.7 with a significance of p < 0.05 was recommended for evaluable results with a baroreflex sensitivity < 3 ms/mm Hg being judged as decreased. We investigated 302 patients (mean age 59 +/- 17 years, 224 males, 78 females). 75% of the investigations showed acceptable results. In 77 cases (25%) reasonable results could not be achieved. We found premature ventricular beats to be responsible in 18 investigations (6% of all investigations). 41 (13.1%) of all investigations were not evaluable because of bad correlation for unknown reason. When we looked closely at these nonevaluable results, we found a significantly higher number of patients with impaired left ventricular ejection fraction (< 40%), diabetes or inducible sustained ventricular tachyarrhythmia in the electrophysiologic study in this group. During all investigations no severe side effects were observed. We conclude that the noninvasive measuring of the baroreflex sensitivity is a save method and leads to reasonable results in 75% of the investigations. In 13.1% it is not possible for unknown reason to achieve sufficiently correlating values. These measurements cannot be evaluated from nowadays' standards and have to be further investigated as they may indicate a population at high risk.

Adult↗