Biomedical subjects

S Nanas

Publications and source records attributed to S Nanas.

At least 19 recordsLinked to original sources

PubMed2005

Patterns of dynamic hyperinflation during exercise and recovery in patients with severe chronic obstructive pulmonary disease.

BACKGROUND: Not all patients with severe chronic obstructive pulmonary disease (COPD) progressively hyperinflate during symptom limited exercise. The pattern of change in chest wall volumes (Vcw) was investigated in patients with severe COPD who progressively hyperinflate during exercise and those who do not. METHODS: Twenty patients with forced expiratory volume in 1 second (FEV(1)) 35 (2)% predicted were studied during a ramp incremental cycling test to the limit of tolerance (Wpeak). Changes in Vcw at the end of expiration (EEVcw), end of inspiration (EIVcw), and at total lung capacity (TLCVcw) were computed by optoelectronic plethysmography (OEP) during exercise and recovery. RESULTS: Two significantly different patterns of change in EEVcw were observed during exercise. Twelve patients had a progressive significant increase in EEVcw during exercise (early hyperinflators, EH) amounting to 750 (90) ml at Wpeak. In contrast, in all eight remaining patients EEVcw remained unchanged up to 66% Wpeak but increased significantly by 210 (80) ml at Wpeak (late hyperinflators, LH). Although at the limit of tolerance the increase in EEVcw was significantly greater in EH, both groups reached similar Wpeak and breathed with a tidal EIVcw that closely approached TLCVcw (EIVcw/TLCVcw 93 (1)% and 93 (3)%, respectively). EEVcw was increased by 254 (130) ml above baseline 3 minutes after exercise only in EH. CONCLUSIONS: Patients with severe COPD exhibit two patterns during exercise: early and late hyperinflation. In those who hyperinflate early, it may take several minutes before the hyperinflation is fully reversed after termination of exercise.

Exercise↗

PubMed2004

Dynamic hyperinflation and tolerance to interval exercise in patients with advanced COPD.

Dynamic hyperinflation (DH) contributes importantly to the limitation of constant-load exercise (CLE) in patients with chronic obstructive pulmonary disease (COPD). However, its role in the limitation of interval exercise (IE) remains to be explored. The change (Delta) in inspiratory capacity (IC) was measured to reflect changes in DH in 27 COPD patients (forced expiratory volume in one second mean+/-SEM % predicted: 40+/-3) at the end of a symptom-limited CLE test at 80% of peak work capacity (WRmax) and an IE test at 100% WRmax (30 s of work, alternated with 30 s of unloaded pedalling). At the limit of tolerance in both IE and CLE, patients exhibited similar DH (DeltaIC: 0.39+/-0.05 L and 0.45+/-0.05 L, respectively). However, exercise endurance time (t end) for IE (32.7+/-3.0 min) was significantly greater than for CLE (10.3+/-1.6 min). The IE t end correlated with resting IC, expressed as % pred normal. At 30 and 90% of total IE t end, DeltaIC (0.43+/-0.06 and 0.39+/-0.05 L, respectively) and minute ventilation (31.1+/-1.6 and 32.7+/-2.2 L.min(-1), respectively) were not significantly different. Resting hyperinflation helps to explain the limitation of interval exercise. Implementation of interval exercise for rehabilitation should provide important clinical benefits because it prolongs exercise endurance time and allows sustaining higher stable ventilation.

Aged↗

PubMed2002

Interval training as an alternative modality to continuous exercise in patients with COPD.

Understanding of what constitutes a training load adequate to induce training effects in patients with chronic obstructive pulmonary disease (COPD) is still evolving. The present study investigated whether interval training (IT) is effective in terms of inducing measurable improvements in physiological response and compared its effects on exercise tolerance (ET) and quality of life to those of continuous training (CT). Thirty-six COPD patients, with a forced expiratory volume in one second of 45+/-4% of the predicted value (mean+/-SEM), were randomly assigned to CT (exercise at 50% of baseline peak work-rate) or IT (work for 30 s at 100% of peak work-rate alternating with 30-s rest intervals) groups that cycled 40 min x day(-1) and 2 days x week(-1) for 12 weeks. After training, both groups showed significantly improved ET (IT, 57+/-6 to 71+/-8 W; CT, 57+/-5 to 70+/-6 W) and total quality-of-life score of the Chronic Respiratory Disease Questionnaire (IT, 77+/-3 to 88+/-2; CT, 78+/-3 to 93+/-2). At identical levels of exercise, minute ventilation was significantly reduced (IT, 35.8+/-2.5 to 31.7+/-2.5 L x min(-1); CT, 36.4+/-2.7 to 32.5+/-2.7 L x min(-1)). The magnitude of improvement in these variables was not significantly different among groups. The present data expand on the principles of exercise prescription for chronic obstructive pulmonary disease patients by demonstrating that interval training elicits substantial training effects, which are similar in magnitude to those produced by continuous training at half the exercise intensity but double the exercise time.

Aged↗

PubMed2001

Early recovery of oxygen kinetics after submaximal exercise test predicts functional capacity in patients with chronic heart failure.

BACKGROUND: Oxygen (O2) uptake at peak exercise (VO2 peak) is an objective measurement of functional capacity in patients with chronic heart failure (CHF). The significance of recovery O2 kinetics parameters in predicting exercise capacity, and the parameters of submaximal exercise testing have not been thoroughly examined. METHODS AND RESULTS: Thirty-six patients (mean age = 48+/-14 years) with CHF and New York Heart Association functional class I, II, or III, and eight healthy volunteers (mean age = 39+/-13 years) were studied with maximal and submaximal cardiopulmonary exercise testing (CPET). The first degree slope of O2 uptake decay during early recovery from maximal (VO2/t-slope), and submaximal exercise (VO2/t-slope)(sub), were calculated, along with VO2 half-time (T(1/2)VO2). Patients with CHF had a longer recovery of O2 uptake after exercise than healthy volunteers, expressed by a lower VO2/t-slope (0.616+/-0.317 vs. 0.956+/-0.347 l min(-1) min(-1), P=0.029) and greater T(1/2)VO2 (1.28+/-0.30 vs. 1.05+/-0.15 min, P = 0.005). VO2/t-slope correlated with the VO2 peak (r = 0.84, P<0.001), anaerobic threshold (r = 0.79, P<0.001), and T(1/2)VO2, a previously established estimate of recovery O2 kinetics (r = -0.59, P<0.001). (VO2/t-slope)(sub) was highly correlated with VO2/t-slope after maximal exercise (r=0.87, P<0.001), with the VO2 peak (r=0.87, P<0.001) and with T(1/2)VO2 after maximal exercise (r=-0.62, P<0.001). VO2/t-slope after maximal and submaximal exercise was reduced in patients with severe exercise intolerance (F=9.3, P<0.001 and F=12.8, P<0.001, respectively). CONCLUSIONS: Early recovery O2 kinetics parameters after maximal and submaximal exercise correlate closely with established indices of exercise capacity in patients with CHF and in healthy volunteers. These findings support the use of early recovery O2 kinetics after submaximal exercise testing as an index of functional capacity in patients with CHF.

Adult↗

PubMed2001

Prolonged oxygen kinetics during early recovery from maximal exercise in adult patients with cystic fibrosis.

STUDY OBJECTIVES: To explore the significance of oxygen kinetics during early recovery after maximal cardiopulmonary exercise testing (CPET) in the assessment of functional capacity and severity of the disease in cystic fibrosis (CF) patients. PARTICIPANTS: Eighteen patients with CF (9 male/9 female; mean +/- SD age, 23 +/- 13 years) and 11 healthy subjects (3 male/8 female; mean age, 29 +/- 4 years) underwent maximum CPET on a treadmill. Breath-by-breath analysis was used for measuring oxygen consumption (VO(2)), carbon dioxide production, and ventilation. Maximum VO(2) (VO(2)peak) and the first-degree slope of VO(2) decline during early recovery (VO(2)/t-slope) were calculated. To assess the severity of the disease, we used standard indexes like FEV(1) (% predicted), VO(2)peak, and a widely accepted system of clinical evaluation, the Schwachman score (SS). RESULTS: VO(2)/t-slope was significantly lower in CF patients compared to healthy subjects (0.61 +/- 0.31 L/min/min vs 1.1 +/- 0.13 L/min/min; p < 0.01) and was closely correlated to FEV(1)(r = 0.90, p < 0.001), VO(2)peak (r = 0.81, p < 0.001), and the SS (r = 0.81, p < 0.001). The multivariate analysis showed that the only independent predictor of the SS is the VO(2)/t-slope. CONCLUSION: We conclude that in CF patients, the prolonged oxygen kinetics during early recovery from maximal exercise is related to the disease severity.

Adolescent↗

PubMed1999

Respiratory muscles performance is related to oxygen kinetics during maximal exercise and early recovery in patients with congestive heart failure.

BACKGROUND: Dyspnea and fatigue are the main causes of exercise limitation in chronic heart failure (CHF) patients, whose peak inspiratory (Pi(max)) and expiratory pressures (Pe(max)) are often reduced. The aim of this study was to examine the relationship between respiratory muscle performance and oxygen kinetics. METHODS AND RESULTS: A total of 55 patients (NYHA class I to III) and 11 healthy subjects underwent cardiopulmonary exercise tests (CPET) on a treadmill. In 45 of the 55 patients (group I) and in healthy subjects (group II), pulmonary function tests, Pi(max), and Pe(max) were measured before and 10 minutes after exercise, and oxygen kinetics were monitored throughout and during early recovery from CPET. The first degree slope of oxygen consumption (VO(2)) decline during early recovery (VO(2)/t-slope) and VO(2) half-time (T(1/2)) were calculated. In 10 of the 55 CHF patients (group III), the measurements of Pi(max) were repeated 2, 5, and 10 minutes after CPET. A >10% reduction in Pi(max) after CPET (subgroup IA) was measured in 11 of 45 patients. In contrast, 34 of 45 CHF patients (subgroup IB) and all control subjects (group II) had Pi(max)>90% of baseline value after CPET. Subgroup IA patients had significantly lower peak VO(2) (13.5+/-2.1 versus 17.8+/-5.6 mL. kg(-1). min(-1); P<0.001), lower anaerobic thresholds (10.1+/-2.4 versus 13.6+/-4.6 mL. kg(-1). min(-1); P=0.003) and lower VO(2)/t-slopes (0.365+/-0.126 versus 0.519+/-0.227 L. min(-1). min(-1); P=0.008) than subgroup IB patients. CONCLUSIONS: The reduction of Pi(max) after exercise is associated with prolonged early recovery of oxygen kinetics, which may explain, in part, the role played by respiratory muscles in exercise intolerance in CHF patients.

Adult↗

PubMed1998

The diagnostic value of gram stain of bronchoalveolar lavage samples in patients with suspected ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is one of the most common causes of morbidity and mortality in intensive care unit patients. However, the diagnosis is quite difficult. Gram stain (GS) of bronchoalveolar lavage (BAL) sample is a time-saving diagnostic method for VAP. However, its clinical significance has not been adequately investigated. The aim of this study was to determine its sensitivity and specificity for VAP diagnosis. We prospectively performed GS and quantitative bacterial cultures (QBC) of BAL samples, obtained through fiberoptic bronchoscope, in 75 consecutive postoperative and/or multiple trauma patients with suspected VAP. We considered BAL-GS as positive for VAP diagnosis when (i) polymorphonuclear neutrophils were > 25 per optic field at a magnification x 100 (p.o.f x 100); (ii) squamous epithelial cells were < 1% p.o.f x 100; and (iii) one or more microorganisms were seen p.o.f. at a magnification x 1,000 (p.o.f. x 1,000). VAP was diagnosed with criteria similar to those used in previous studies. Pneumonia was the final diagnosis in 22/75 (29%) patients. The BAL-GS was positive in 17/22 patients with VAP and in 7/53 patients without VAP. Accordingly, the sensitivity of BAL-GS for VAP diagnosis was 77%, the specificity 87%, the positive predictive value 71% and the negative predictive value 90%. Our data suggest that BAL-GS has good sensitivity and high specificity for VAP diagnosis. It could therefore constitute a useful complementary tool in the task of early diagnosis and treatment of VAP.

Adolescent↗

PubMed1997

A decision support software package for medical treatment of I.C.U. patients.

Critically ill patients admitted in I.C.U. often have multiple complicated problems which necessitate the use of a large number of drugs. The multiple potential interactions between substances and underlying pathologies as well as between substances themselves, obviate the need for a decision support system. We therefore developed a software package for medical treatment support in I.C.U. environment which is based on Microsoft Visual Basic 3.0 and it is organised around the commercially available RDBMS Access 2.0. The database consist of: a) all available substances, b) all generic names of medications available in Greece for each substance, c) incompatibilities (2,300 cases), d) interactions (50,000 cases) and e) cost information for each drug. This system assures the safety of the administered treatment, helps to adjust the dose according to the situation of each patient (anthropometric data, laboratory result, prognostic/severity score e.t.c.) and screens for possible interactions and incompatibilities between the administered drugs. It could also be used for education, treatment algorithms application and it will serve cost-reduction policy. It is a useful and powerful tool for ICU staff which does not impose additional work to the daily practice routine and it is currently under evaluation in clinical settings.

Adverse Drug Reaction Reporting Systems↗

PubMed1997

Conditional evaluation of broncho-alveolar lavage in mechanically ventilated patients with suspected unilateral lobar pneumonia.

OBJECTIVE: In an attempt to improve our ability to diagnose the cause of ventilator-associated pneumonia (VAP), we explore the usefulness of the conditional evaluation of bronchoalveolar lavage (BAL) samples from the involved and non-involved areas in patients with suspected unilateral lobar VAP (UL-VAP). DESIGN: Prospective study. SETTING: University teaching hospital intensive care unit. PATIENTS: We studied 19 consecutive patients with suspected UL-VAP. MEASUREMENTS AND MAIN RESULTS: Nine of the 12 patients (47%) developed UL-VAP. There was a significant difference between the involved and non-involved areas in UL-VAP patients (P < 0.001) in respect of the quantitative bacterial cultures (QBCs) of BAL samples for each micro-organism, whereas there was no difference in patients without UL-VAP. When we applied the criterion of usual BAL (one micro-organism in concentrations > 10(5) colony-forming units per millilitre) for UL-VAP diagnosis, the sensitivity was 100%, the specificity 70%, the positive predictive value 75%, and the negative predictive value 100%. When we used the conditional evaluation of the BAL results for UL-VAP diagnosis, in the involved and non-involved areas, the sensitivity was 78%, the specificity 90%, the positive predictive value 87.5% and the negative predictive value 82%. A statistically significant difference was found when we compared the difference in QBCs between the BAL samples for each micro-organism, between the involved and non-involved areas in patients with and without VAP (P < 0.001). CONCLUSION: These data suggest that utilisation of the conditional evaluation of the QBCs of BAL samples improves significantly our ability to diagnose the cause of UL-VAP.

Adult↗

PubMed1997

The application of image analysis in the measurement of the myocardial infarct area in an experimental model.

BACKGROUND: Thrombolytic therapy improves left ventricular ejection fraction and survival. Using the image analysis method, the study was undertaken to evaluate the effects of intraaortic balloon pump used in conjunction with reperfusion in reducing infarct size by measuring the infarct area. Also, the usefulness of image analysis as an objective method for the measurement of myocardial infarct area is evaluated. METHODS: 22 dogs were subjected to proximal left anterior descending coronary artery occlusion. The dogs were classified into 3 groups. In group I (n = 7), occlusion lasted for 6 hours. In group II (n = 6), 2 hours of occlusion were followed by reperfusion. In group III, (n = 9) after 2 hours of occlusion, the dogs were assisted with the intraaortic balloon pump throughout the 4 hours of reperfusion. The measurement of the infarcted area components (fragmentation, edema, hemorrhage and polymorphonuclear infiltrations) was followed by a semiautomatic method including in connection a microscope photographic camera, a scanner and a computer with the appropriate software. The results were analyzed statistically using the t-test. RESULT: In group I, the mean value of fragmentation was 28.2%, in group II, 10.1% (p < 0.01 versus group I) and in group III, 3.9% (p < 0.01 versus I and p < 0.05 versus group II). CONCLUSION: Reperfusion and intraaortic balloon pump increased the salvage of the ischemic myocardium over that achieved by reperfusion alone in a canine occlusion - reperfusion model. Image analysis could be considered as an accurate and objective method for the measurement of the myocardial infarct area in the experimental model of our study and it could be used in any other experimental study in which the accurate measurement of myocardial infarct area is needed.

Animals↗

PubMed1993

Expression of vimentin and epidermal growth factor receptor in effusions from patients with breast cancer; correlation with oestrogen and progesterone receptor status.

The epidermal growth factor receptor (EGFr) status and the vimentin (V) status of malignant cells in pleural fluids from patients with breast cancer were determined using an immunoperoxidase labelling technique. The results were correlated with the oestrogen receptor (ER) and the progesterone receptor (PR) status of the primary tumour and with disease-free survival time of the patient. A negative correlation between EGFr and V status and hormone receptor status was found. The longest mean survival time occurred in patients with negative EGFr and V status and positive hormone receptor (ER and PR) status. The shortest mean survival time occurred in patients with positive EGFr and V and negative ER and PR status.

Adult↗

PubMed1992

Adaptations of the peripheral circulation to PEEP.

The purpose of this study was to determine the role of changes in the parameters of venous return on the homeostatic adaption to the application of PEEP. We studied 13 dogs anesthetized with alpha-chloralose, intubated, and ventilated. We measured central venous pressure (CVP), arterial pressure (Pao) and cardiac output by thermal dilution. The cardiac output was transiently stopped by inflating a balloon in the right atrium, and the subsequent plateau in the CVP was used to obtain mean circulatory filling pressure (MCFP). Total blood volume was measured with Evans blue. To measure vascular capacitance and compliance, we rapidly infused 4 ml/kg or 8 ml/kg of blood and repeated the MCFP measurement. The same volume was withdrawn after the measurement. The volume and MCFP were used to construct pressure-volume (P-V) lines, and the unstressed volume was calculated by extrapolating the P-V to zero pressure. The P-V appeared linear in the range studied. PEEP produced a left shift of the curves and, thus, a decrease in unstressed volume. The shift with 20 cm H2O of PEEP was greater than with 10 cm H2O of PEEP. The rise in MCFP matched the rise in CVP so that the pressure gradient for venous return did not change. However, there was also an increase in the resistance to venous return, which resulted in a lower cardiac output than expected for the rise in MCFP. In conclusion, homeostatic adjustments to PEEP included a decrease in vascular capacitance, which is partially offset by a rise in the resistance to venous return.

Adaptation, Physiological↗

PubMed1987

The role of relative weight in the positive association between age and serum cholesterol in men and women.

With advancing age from youth on, there is an increase in mean serum cholesterol level of populations in "western" industrialized countries. Since serum cholesterol is one of the established major risk factors for premature coronary heart disease, it is important to explore the degree to which this age trend is physiologic or due to modern life styles. This study used cross-sectional data for 19,730 white men and 13,872 white women from the Chicago Heart Association Detection Project in Industry to investigate one aspect of this question: does weight explain the association between age and serum cholesterol, in particular whether older age is associated with higher serum cholesterol in the absence of overweight. The relationships among age, relative weight, and serum cholesterol were examined through assessment of mean serum cholesterol levels in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, 55-64) and by relative weight (less than 100, 100-109, 110-119, 120-134, greater than or equal to 135). Age and serum cholesterol were positively associated with each other. In women, it was a simple, linear relationship. In men, the degree of this positive association was less in people over age 35-44 than people in younger ages. These age-cholesterol patterns were present in men and women at desirable weight. However, in men aged 18-54, the positive association between age and prevalence of marked hypercholesterolemia (serum cholesterol greater than or equal to 250) was lower in people at desirable relative weight in comparison to those at higher relative weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1987

Detection of arrhythmias in a representative sample of the Athens population.

The prevalence and type of arrhythmias has been studied in a representative sample of 2000 Athenians, aged 18-81 years, who underwent exercise testing on a treadmill according to the Bruce protocol. It was found that 121 persons (mean age 55.7 +/- 14.9 years, 31% greater than 65 years), exhibited arrhythmias on the ECG during either the exercise or the 10 min period following it (prevalence 6.05%). The age-adjusted prevalence was 6.7%, that is 7.1% for men and 6.2% for women. Out of these 2000 Athenians 43 (2.15%) exhibited unifocal VPCs (23 with greater than or equal to 3 VPCs min-1 and 20 with less than 2 VPCs min-1), 10 (0.5%) multifocal VPCs (6 with single and 4 with paired VPCs), 12 (0.6%) bigeminy, 25 (1.25%) supraventricular PCs, 16 (0.8%), supraventricular PCs and VPCs, 5 (0.25%) respiratory arrhythmia, 3 (0.15%) coronary sinus rhythm, 3 (0.15%) atrial fibrillation, one (0.05%) ventricular tachycardia, 2 (0.1%) first-degree and one (0.05%) second-degree AV block. In 32 out of those 121 persons arrhythmias were present also at rest (26.5%). Ventricular premature contractions and/or supraventricular PCs were the most common type of arrhythmias (87.6%). The majority of VPCs (69%) and supraventricular PCs (80%) appeared during the 10-min observation period following exercise. Coronary heart disease and valvular heart defects were found more frequently among the participants with than those without arrhythmias at exercise testing (19.83% vs. 8.83% and 2.48% vs. 0.27%, respectively).

Adolescent↗

PubMed1986

The role of weight in the positive association between age and blood pressure.

This study used cross-sectional data for 19,704 white men and 13,895 white women from the Chicago Heart Association Detection Project in Industry (November 1967 to January 1973) to investigate whether weight explains the association between age and blood pressure, and in particular, whether age is associated with blood pressure and hypertension in the absence of overweight. The relations among age, relative weight, and blood pressure were examined through assessment of mean blood pressure levels and prevalence of hypertension in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, and 55-64 years) and by relative weight (less than 100%, 100-109%, 110-119%, 120-134%, and greater than or equal to 135%). For all five relative weight groups, for both men and women, mean diastolic blood pressure was higher at successive ages. This phenomenon was also seen for systolic blood pressure after ages 35-44 years for men, and after ages 25-34 years for women. On the other hand, the higher the relative weight was, the higher the blood pressure was. Regression analysis demonstrated that the observed relation between age and blood pressure was consistent for all five relative weight groups, including those at desirable weight. These data indicate that for US subjects, age and blood pressure are generally associated in the absence of overweight.

Adolescent↗

PubMed1986

Medical education and experience affecting intra-observer variability.

Intra-observer variability for history and simple test evaluation was assessed in a group of 10 final-year medical students and in five senior hospital staff members. Substantial agreement between the results of two evaluations made 7-10 days apart was found in 20 out of 30 instances for staff and in 17 out of 60 instances for students. However, there were instances when variability seemed to be unrelated to the academic standard of students or to the training and experience of staff. It is concluded that the nature of diagnostic procedure and present training in medical school or long-term experience may not be the only factors that affect intra-observer variability in everyday simple diagnostic applications.

Diagnosis↗

PubMed1984

A randomized trial on the effect of decreased dietary sodium intake on blood pressure in adolescents.

A randomized crossover trial on the effect of salt restriction on blood pressure was carried out involving 124 adolescents (mean age 16 years). Dietary sodium was reduced from approximately 110 to 45 mEq/24 h for a period of 24 days. Blood pressure was non-significantly lower at the end of the experimental diet for all participants. A slight (0.7 kg), yet statistically significant fall in weight was observed (P less than 0.05). Subgroup analysis demonstrated that participants whose body mass index was below the median had a statistically significant fall in systolic blood pressure (P less than 0.05); fall in weight and increase in heart rate were also more pronounced in the less obese individuals. It would appear that moderate sodium reduction does not have an overall short-term effect on blood pressure in normotensive adolescents. However, body size as reflected in body mass index may influence blood pressure response to sodium reduction.

Adolescent↗

PubMed1983

Increased sodium-lithium countertransport in college students with elevated blood pressure.

Blood pressure screening was carried out on a university campus to identify early hypertension or high-normal BP in young adults. Compared with normotensive control subjects of a similar age, drawn from the same population, persons identified as being at the upper end of the BP distribution had significantly increased levels of sodium-lithium countertransport. This difference persisted when other potential confounding variables, eg, overweight, sex, ethnicity, sodium excretion, and age, were taken into account. A positive family history was associated with slightly higher levels of sodium-lithium countertransport, although the effect could be explained by higher present levels of BP. These data suggest that abnormalities of cation transport are present early in the course of the development of hypertension. Measurement of transport levels may provide an estimate of risk of hypertension and allow identification of susceptible persons.

Adult↗