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PubMed2005

The German view: effects of nitrogen dioxide on human health--derivation of health-related short-term and long-term values.

The presented overview concerning health relevant effects caused by nitrogen dioxide (NO2) resumes the current state of results from animal experiments and human studies (epidemiology and short-term chambers studies). NO2 concentrations applied in animal experiments were mostly considerably higher than in ambient air. Therefore, short- and long-term limit values were derived from human data. Experimental studies conducted with humans demonstrate effects after short-term exposure to concentrations at or above 400 microg NO2/m3. Effects on patients with light asthma could not be observed after short-term exposure to concentrations below 200 microg/m3. On basis of epidemiological long-term studies a threshold below which no effect on human health is expected could not be specified. Two short-term limit values have been proposed to protect public health: a 1-h value of 100 microg/m3 and a 24-h mean value of 50 microg/m3. Due to the limitations of epidemiological studies to disentangle effects of single pollutants, a long-term limit value cannot be easily derived. However, applying the precautionary principle, it is desirable to adopt an annual mean of 20 microg NO2/m3 as a long-term mean standard to protect public health.

Air Pollutants↗
PubMed1992

Temporomandibular-related pressure thresholds: a model for establishing baselines.

The use of pressure threshold measurement to quantify tender spots and trigger points in muscles is well established. Its application to the field of temporomandibular disorders, however, has been more recent and less widely published. Pressure threshold measurement may be useful to define values for dysfunctional muscles or structures so that changes in muscle condition through a course of treatment can be quantified. Normal values for many muscles in the body have been established, but studies of this type in the masticatory system are limited and have often used a fixed, pre-determined pressure cutoff, rather than measuring thresholds across a number of patients. This pilot study seeks to determine whether normal values exist for the anterior temporalis muscles, the masseter muscles, and the lateral capsules of the temporomandibular joints. Intrarater and interrater reliability in measuring thresholds was also studied with the aim of contributing toward a methodological model for further study.

Adolescent↗
PubMed1995

Threshold estimation in single photon emission computed tomography and planar imaging for clinical radioimmunotherapy.

Thresholding is the most widely used organ or tumor segmentation technique used in single photon emission computed tomography (SPECT) and planar imaging for monoclonal antibodies. Selecting the optimal threshold requires a priori knowledge (volumes from CT or magnetic resonance) for the size and contrast level of the organ in question. Failure to select an optimal threshold leads to overestimation or underestimation of the volume and, subsequently, the organ-absorbed dose value in radio-immunotherapy. To investigate this threshold selection problem, we performed a phantom experiment using six lucite spheres ranging from 1 to 117 ml and filled with a uniform activity of 1 microCi/ml Tc-99m. These spheres were placed at the center and off-center locations of a Jasczsak phantom and scanned with a three-headed gamma camera in SPECT and planar modes. Target-nontarget (T:NT) ratios were changed by adding the appropriate activity to the background. A threshold search algorithm with an interpolative background correction was applied to sphere images. This algorithm selects a threshold that minimizes the difference between the true and measured volumes (SPECT) or areas (planar). It was found that for spheres equal to or larger than 20 ml [diameter (D) > 38 mm] and T:NT ratios higher than 5:1, mean thresholds at 42% for SPECT and 38% for planar imaging yielded minimum image segmentation errors, which is in agreement with current literature. However, for small T:NT ratios (< 5:1), the threshold values as high as 71% for SPECT and 85% for planar imaging were substantially different than those fixed thresholds for large spheres (D > 38 mm). Hence, the use of fixed thresholds in low contrasts and with tumor and organ sizes of clinical interest (25 < or = D < or = 50 mm) may result in limited volume estimation accuracy. Therefore, we have provided the investigator a method to obtain the threshold values in which the proper threshold can be selected based on the organ and tumor size and image contrast. By measuring and calibrating the proper threshold value derived through machine-specific phantom measurements, a more accurate volume and activity quantitation can be performed. This, in turn, will provide tumor-absorbed dose optimization and greater accuracy in the measurement of potentially subacute, toxic absorbed doses to normal organs for patients undergoing radioimmunotherapy.

Algorithms↗
PubMedDate not supplied

UV radiation as a potential driving force for zooplankton community structure in Patagonian lakes.

This article explores the potential role of UV radiation (UVR) as an influence on zooplankton communities. In the first section we provide a general overview of UVR effects on freshwater zooplankton, with an emphasis on Argentine and Chilean environments. In the second section we present the results of a survey involving 53 temperate lakes across a gradient of UVR exposure to determine patterns of species richness and specific diversity. These community characteristics decreased at high potential UVR exposure (i.e. high mean water column irradiance or low lake optical density). A threshold value of mean water column irradiance of approximately 10% of the surface level seems to limit both richness and diversity to minimum values. On the basis of the collected evidence it is not possible to definitely conclude that UVR rather than another covarying factor is responsible for the decrease in specific diversity observed at the lowest end of lake optical depth. However, lakes with values above the previous threshold are likely to exhibit highly depauperate zooplankton communities regardless of the mechanism. As a cautionary note we suggest that changes in the optical characteristics (i.e. changes due to atmospheric conditions, precipitation patterns or vertical displacement of the tree line) may result in sudden shifts in zooplankton community structure.

Animals↗
PubMed1988

Relationships between anaerobic threshold and exercise hemodynamic pattern in patients with previous myocardial infarction.

UNLABELLED: In 78 male class I and II NYHA patients with previous myocardial infarction, the relationships between ventilatory anaerobic threshold levels and hemodynamic patterns during a maximal symptom-limited stress test in the supine position were studied. Among the 36 patients with abnormal exercise wedge values, 11 showed an anaerobic threshold (AT) less than 35% of the maximal predicted VO2(mpVO2) (group A) and 23 showed an AT of 36-50% mpVO2 (group B). In 2 patients, the AT was greater than 50% mpVO2. Among the 42 patients with normal exercise wedge pressure, 13 showed an AT of 36-50% mpVO2 (group C), whereas in 29 patients, the AT was greater than 50% mpVO2 (group D). The mean value of AT in group A was significantly lower than in group B (8.6 +/- 0.7 vs. 11.7 +/- 0.5 ml/kg.min; p less than 0.05). No difference was found in the mean of the AT between groups B and C, while the mean value of AT in group D was significantly higher than in group C (16.9 +/- 0.4 vs. 12.9 +/- 0.6 ml/kg.min; p less than 0.005). No significant differences between groups C and D were found in the invasive and noninvasive parameters considered. Groups C and D were statistically different from groups A and B for pulmonary capillary pressures, total pulmonary resistances, stroke indexes, heart rates, arteriovenous O2 differences, total systemic resistances and lactate concentrations. Total pulmonary resistances and heart rates were statistically higher and stroke indexes were statistically lower in group A than in group B. IN CONCLUSION: (1) patients with normal exercise wedge values show a higher AT than patients with abnormal exercise wedge values. (2) Patients with normal exercise hemodynamic patterns classified according to their AT show no difference in hemodynamics; in these patients the level of AT seems to be related to peripheral determinants. (3) Patients with abnormal exercise hemodynamic patterns classified according to their AT level show different hemodynamics and different responses in ventricular function; in these patients the level of AT seems to be related to the cardiac impairment.

Adult↗
PubMed1999

Hydration energies and structures of alkaline earth metal ions, M2+(H2O)n, n = 5-7, M = Mg, Ca, Sr, and Ba.

The evaporation of water from hydrated alkaline earth metal ions, produced by electrospray ionization, was studied in a Fourier transform mass spectrometer. Zero-pressure-limit dissociation rate constants for loss of a single water molecule from the hydrated divalent metal ions, M(2+)(H(2)O)(n) (M = Mg, Ca, and Sr for n = 5-7, and M = Ba for n = 4-7), are measured as a function of temperature using blackbody infrared radiative dissociation. From these values, zero-pressure-limit Arrhenius parameters are obtained. By modeling the dissociation kinetics using a master equation formalism, threshold dissociation energies (E(o)) are determined. These reactions should have a negligible reverse activation barrier; therefore, E(o) values should be approximately equal to the binding energy or hydration enthalpy at 0 K. For the hepta- and hexahydrated ions at low temperature, binding energies follow the trend expected on the basis of ionic radii: Mg > Ca > Sr > Ba. For the hexahydrated ions at high temperature, binding energies follow the order Ca > Mg > Sr > Ba. The same order is observed for the pentahydrated ions. Collisional dissociation experiments on the tetrahydrated species result in relative dissociation rates that directly correlate with the size of the metals. These results indicate the presence of two isomers for hexahydrated magnesium ions: a low-temperature isomer in which the six water molecules are located in the first solvation shell, and a high-temperature isomer with the most likely structure corresponding to four water molecules in the inner shell and two water molecules in the second shell. These results also indicate that the pentahydrated magnesium ions have a structure with four water molecules in the first solvation shell and one in the outer shell. The dissociation kinetics for the hexa- and pentahydrated clusters of Ca(2+), Sr(2+), and Ba(2+) are consistent with structures in which all the water molecules are located in the first solvation shell.

Journal Article↗
PubMed1994

Comparison of two protocols used in exercise testing in chronic heart failure patients.

UNLABELLED: Spiroergometrical testing with the load graded upto symptom-limited maximum with the determination of anaerobic threshold begins to be a routine method in exercise testing of cardiac patients. Functional parameters according to available data depend on the source of load and may be influenced by the protocol of testing, too. That is why we decided to compare two protocols used in chronic heart failure patients exercise testing. 11 male and 3 female patients (NYHA II, III) suffering from chronic heart failure were subjected to the symptom-limited tests (protocol A-0.25 W.kg (-1/3 minutes with one minute breaks; protocol B-25 W + 10 W/2 minutes). There was no statistically significant differences in the symptom-limited values of main functional parameters. The AT level parameters did not differ significantly, as well. Anaerobic threshold could be determined in all patients using the protocol A and in 11 cases using the protocol B. The difference in rates was not statistically significant. The workload duration using the protocol B was significantly shorter (9.7 +/- 3.8 minutes vs. 16.4 +/- 3.6 minutes). CONCLUSIONS: Protocol B is less time demanding and therefore it is more suitable for determination of the symptom-limited parameters in the clinical routine. Anaerobic threshold can be determined by protocol A more often than by protocol B. Therefore, protocol A appears to be more suitable for the individual prescription of the appropriate physical activity and for scientific purposes, too.

Anaerobic Threshold↗
PubMed1998

Breathing reserve at the lactate threshold to differentiate a pulmonary mechanical from cardiovascular limit to exercise.

STUDY OBJECTIVES: Criteria used to define the respective roles of pulmonary mechanics and cardiovascular disease in limiting exercise performance are usually obtained at peak exercise, but are dependent on maximal patient effort. To differentiate heart from lung disease during a less effort-dependent domain of exercise, the predictive value of the breathing reserve index (BRI=minute ventilation [VE]/maximal voluntary ventilation [MVV]) at the lactate threshold (LT) was evaluated. DESIGN: Thirty-two patients with COPD and a pulmonary mechanical limit (PML) to exercise defined by classic criteria at maximum oxygen uptake (VO2max) were compared with 29 patients with a cardiovascular limit (CVL) and 12 normal control subjects. Expired gases and VE were measured breath by breath using a commercially available metabolic cart (Model 2001; MedGraphics Corp; St. Paul, Minn). Arterial blood gases, pH, and lactate were sampled each minute during exercise, and cardiac output (Q) was measured by first-pass radionuclide ventriculography (System 77; Baird Corp; Bedford, Mass) at rest and peak exercise. RESULTS: For all patients, the BRI at lactate threshold (BRILT) correlated with the BRI at VO2max (BRIMAX) (r=0.85, p<0.0001). The BRILT was higher for PML (0.73+/-0.03, mean+/-SEM) vs CVL (0.27+/-0.02, p<0.0001), and vs control subjects (0.24+/-0.03, p<0.0001). A BRILT > or = 0.42 predicted a PML at maximum exercise, with a sensitivity of 96.9%, a specificity of 95.1%, a positive predictive value of 93.9%, and a negative predictive value of 97.5%. CONCLUSIONS: The BRILT, a variable measured during the submaximal realm of exercise, can distinguish a PML from CVL.

Cardiac Output↗
PubMed2005

Extremal dynamics on complex networks: analytic solutions.

The Bak-Sneppen model displaying punctuated equilibria in biological evolution is studied on random complex networks. By using the rate equation and the random walk approaches, we obtain the analytic solution of the fitness threshold xc to be 1/((k)f+1), where (k)f=(k2)/(k) (=(k)) in the quenched (annealed) updating case, where kn is the nth moment of the degree distribution. Thus, the threshold is zero (finite) for the degree exponent gamma<3 (gamma>3) for the quenched case in the thermodynamic limit. The theoretical value xc fits well to the numerical simulation data in the annealed case only. Avalanche size, defined as the duration of successive mutations below the threshold, exhibits a critical behavior as its distribution follows a power law, Pa(s) approximately s(-3/2).

Journal Article↗
PubMed2001

A follow-up study on occupational exposure to inhaled anaesthetics in Eastern European surgeons and circulating nurses.

OBJECTIVE: Although no dose-response relationship exists for the health risks associated with the occupational exposure to inhaled anaesthetics, public health authorities recommend threshold values. The aim of the present study was to assess whether and to what extent these threshold values are exceeded in surgeons and circulating nurses of an Eastern European university hospital, before and after measures had been taken to reduce occupational exposure. METHODS: At nine workplaces, occupational exposure to nitrous oxide and the volatile anaesthetic used (halothane or isoflurane) was measured within the breathing zones of surgeons and circulating nurses by means of photoacoustic infrared spectrometry. The measurements were carried out in 1996 and were repeated in 1997 after the installation of active scavenging devices at five workplaces, and an air-conditioning system at one workplace. RESULTS: Occupational exposure to nitrous oxide and halothane or isoflurane was lower in 1997 compared with that of 1996. In 1996, 89% of the nitrous oxide values were above the European threshold value of 100 ppm, whereas in 1997 approximately 50% were above this limit. In 1996 the majority of the measurements for the volatile anaesthetics were already below 5 ppm halothane and 10 ppm isoflurane and the number of measurements exceeding these limits was further reduced in 1997. CONCLUSION: The measures taken were effective in reducing waste gas exposure. Nevertheless, further efforts are necessary, especially for nitrous oxide, to reach Western European standards and to minimise possible health risks. These efforts comprise the installation of (active) scavenging devices, air-conditioning systems and new anaesthesia machines at all workplaces, the use of low-flow anaesthesia, the replacement of inhaled anaesthetics by intravenous anaesthetics and an appropriate working technique.

Anesthetics, Inhalation↗
PubMed1976

Sustained oscillations and threshold phenomena in an operon control circuit.

A genetic regulatory model involving a positive feedback (via induction) and a negative feedback (via catabolite repression) is analyzed and applied to the problem of the lac operon regulation in E. coli. Damped and sustained oscillations of the limit cycle type are found along with threshold phenomena corresponding to multiple limit cycles or to multiple steady states, for values of the parameters compatible with experimental data. A comparison with the observations of Knorre and Goodwin is outlined.

Escherichia coli↗
PubMed1989

Quantitative single photon emission computed thallium-201 tomography for detection and localization of coronary artery disease: optimization and prospective validation of a new technique.

One hundred eight-three men underwent stress-redistribution thallium-201 myocardial perfusion tomography. After evaluation of various preprocessing filters in a phantom study, the Butterworth filter with a frequency cutoff of 0.2 cycles/pixel, order 5 (which provided optimal filter power) was used in the back projection algorithm of the patient studies. All short-axis and apical portions of vertical long-axis images were quantified by dividing each myocardial slice into 60 equal sectors and displaying the maximal count per sector as a linear profile. In a pilot group consisting of 20 normal men (less than 5% likelihood of coronary artery disease) and 25 men with coronary artery disease (greater than or equal to 50% coronary stenosis by angiography), profiles representing the lowest observed value below the mean normal profiles provided the best threshold for defining normal limits. Abnormal portions of the patient profiles were plotted on a two-dimensional polar map. The polar map was divided into 102 sectors, and sectors with a probability of greater than or equal to 80% for disease of each one of the three major coronary arteries were clustered to represent specific coronary artery territories. Receiver operating characteristic curve analysis for defect size showed that the optimal threshold for defining a definite perfusion defect was 12% for the left anterior descending and left circumflex and 8% for the right coronary artery territories. These criteria were prospectively applied to an additional 92 patients with angiographic coronary artery disease, 18 patients with normal coronary arteriograms and 28 patients with less than 5% likelihood of coronary disease. Sensitivity, specificity (in patients with normal coronary arteriograms) and normalcy rate (in patients with less than 5% likelihood of coronary artery disease) for overall detection of coronary disease were 96%, 56% and 86%, respectively. Sensitivity and specificity for identification of individual diseased vessels were, respectively, 78% and 85% for the left anterior descending, 79% and 60% for the left circumflex and 81% and 71% for the right coronary artery. These results were not significantly different from those of the pilot group. An optimized quantitative method for interpretation of stress thallium-201 myocardial perfusion tomography has been developed. Prospective application of this method indicates that the technique is accurate for the overall detection of coronary artery disease and identification of disease in individual arteries.

Coronary Circulation↗
PubMed2004

Chest radiography for the diagnosis of acute aortic syndrome.

PURPOSE: We sought to assess the diagnostic accuracy of routine chest radiography for the acute aortic syndrome (dissection, intramural hematoma, penetrating ulcer, or nondissecting aneurysm). METHODS: During a 6-year period, 216 patients (143 men, 73 women; mean [+/- SD] age, 58 +/- 17 years) underwent chest radiography for suspected acute aortic syndrome. Chest films were re-evaluated blindly for aortic disease, based on an overall impression using standard criteria such as widening of the aortic contour and mediastinal shadow. Findings were matched to tomographic images, anatomical inspection, or both, as the criterion standard; aortic disease was confirmed in 109 (50%) of the patients. RESULTS: Chest radiography had a sensitivity of 64% (70/109) and a specificity of 86% (92/107) for aortic disease. Sensitivity was 67% (38/57) for overt aortic dissection, 61% (22/36) for nondissecting aneurysm, and 63% (10/16) for intramural hemorrhage or penetrating ulcer. However, sensitivity was lower for pathology confined to the proximal aorta (47% [21/45]) than for disease involving distal aortic segments (77% [49/64]). A receiver operating characteristic curve analysis of aortic diameters failed to identify a threshold for the diagnosis of aortic disease. CONCLUSION: Chest radiography is of limited value for diagnosing the acute aortic syndrome, particularly for conditions confined to the ascending aorta. Since a definitive diagnosis is required in any patient with clinically suspected acute aortic syndrome, routine chest radiography should be replaced by tomographic aortic imaging.

Acute Disease↗
PubMed2003

A tobit variance-component method for linkage analysis of censored trait data.

Variance-component (VC) methods are flexible and powerful procedures for the mapping of genes that influence quantitative traits. However, traditional VC methods make the critical assumption that the quantitative-trait data within a family either follow or can be transformed to follow a multivariate normal distribution. Violation of the multivariate normality assumption can occur if trait data are censored at some threshold value. Trait censoring can arise in a variety of ways, including assay limitation or confounding due to medication. Valid linkage analyses of censored data require the development of a modified VC method that directly models the censoring event. Here, we present such a model, which we call the "tobit VC method." Using simulation studies, we compare and contrast the performance of the traditional and tobit VC methods for linkage analysis of censored trait data. For the simulation settings that we considered, our results suggest that (1) analyses of censored data by using the traditional VC method lead to severe bias in parameter estimates and a modest increase in false-positive linkage findings, (2) analyses with the tobit VC method lead to unbiased parameter estimates and type I error rates that reflect nominal levels, and (3) the tobit VC method has a modest increase in linkage power as compared with the traditional VC method. We also apply the tobit VC method to censored data from the Finland-United States Investigation of Non-Insulin-Dependent Diabetes Mellitus Genetics study and provide two examples in which the tobit VC method yields noticeably different results as compared with the traditional method.

Analysis of Variance↗
PubMed2002

Biophysical considerations on low dose radiation risk.

Considerations about the action of low radiation doses and the applicability of the collective dose concept have to take into account that radiation interaction and the formation of initial lesions are discrete processes. With increasing LET the number of hit cells per unit dose is reduced while the energy deposited in the nuclei of affected cells increases. A cell without initial radiation induced lesions cannot be mutated; an organ without a mutant cell cannot develop a tumour. This paper considers this problem in a quantitative manner taking into account also the limited number of tumour target stem cells. Based on these considerations 'practical threshold' values of equivalent doses are proposed.

Cell Transformation, Neoplastic↗
PubMed1998

Riboflavin and vitamin B-6 intakes and status and biochemical response to riboflavin supplementation in free-living elderly people.

Free-living elderly people aged > or = 65 y were recruited to assess riboflavin and vitamin B-6 intakes and status and the effect of riboflavin supplementation on biochemical indicators of these 2 vitamins. The status of riboflavin (erythrocyte glutathione reductase activation coefficient; EGRAC) and vitamin B-6 (plasma pyridoxal-5'-phosphate; PLP) were determined in a total sample of 92 subjects, from whom dietary intake data were obtained by using the diet history method (n = 83). Although dietary intakes of both vitamins were considered to be adequate according to current reference values, abnormal EGRAC and plasma PLP values were identified in 49% and 38% of subjects, respectively, with 21% having suboptimal status for both nutrients. A subgroup of subjects from the initial sample (n = 45) was assigned in a double-blind manner to receive either 1.6 or 25 mg riboflavin or placebo daily for 12 wk. In those subjects with a baseline EGRAC or plasma PLP value falling outside the currently accepted threshold value for adequacy, low-dose riboflavin supplementation improved status of the limiting nutrient significantly (P<0.0001 and P = 0.020 for EGRAC and plasma PLP responses, respectively). We conclude that a high proportion of healthy elderly people may have suboptimal status for these nutrients despite apparently adequate dietary intakes. Furthermore, we showed that riboflavin supplementation at physiologic doses corrects biochemical abnormalities of not only EGRAC, but also plasma PLP, confirming the biochemical interdependency of these vitamins and suggesting that riboflavin is the limiting nutrient.

Age Factors↗
PubMed2005

Determinants for nasal trigeminal detection of volatile organic compounds.

We explored the influence of methodological and chemical parameters on the detection of nasal chemesthesis (i.e., trigeminal stimulation) evoked by volatile organic compounds (VOCs). To avoid odor biases, chemesthesis was probed via nasal pungency detection in anosmics and via nasal localization (i.e., lateralization) in normosmics, in both cases using forced-choice procedures. In the experiments with anosmics, 12 neat VOCs were selected based on previous reports of lack of chemesthetic response. Although none of the VOCs reached 100% detection, detectability and confidence of detection were higher when using a glass vessel system adapted with nosepieces to fit the nostrils tightly than when using wide-mouth glass jars. Half the stimuli were detected well above chance and half were not. When the latter were tested again after being heated to 37 degrees C, that is, body temperature (from room temperature, 23 degrees C), to increase their vapor concentration, only one, octane, significantly increased its detectability. Chemesthesis gauged with normosmics mirrored that with anosmics. Gas chromatography measurements showed that, even at 23 degrees C, the saturated vapor concentrations of the undetected stimuli, except vanillin, were well above the respective calculated nasal pungency threshold (NPT) from an equation that, in the past, had accurately described and predicted NPTs. We conclude that, except for octane and perhaps vanillin, the failure of the other four VOCs to precipitate nasal chemesthesis rests on a chemical-structural limitation, for example, the molecules lack a key property to fit a receptor pocket, rather than on a concentration limitation, for example, the vapor concentration is too low to reach a threshold value.

Adult↗
PubMed1997

Salivary parameters of relevance for assessing caries activity in individuals and populations.

A review of the non-microbial salivary parameters with respect to their possible association with caries activity is presented. The parameters are limited to those which already are or at least in the near future will obviously be simple enough, also for clinical purposes. Salivary flow rate is undoubtedly the most important single parameter since the cariostatic activity or efficacy of practically all other salivary parameters depends on the flow rate. Flow rate as such has no linear association with dental caries but there seems to exist an individual "threshold" limit which is decisive for enhanced caries activity. This threshold limit varies among different individuals and therefore the so-called normal values for unstimulated or stimulated flow rate are more reliable on a population level than among individuals for screening purposes. In any individual a regular and longitudinal follow-up of the flow rate is of higher clinical value than only a single cross-sectional measurement. Salivary buffer effect has only a weak negative association with caries activity and again, this effect is of greater clinical significance on a population level. Since the decisive processes in caries attack occur within or under the dental plaque, the buffering effect of saliva is limited and obviously more important to screen for erosion-than caries-prone individuals. Although important for dental health, none of the salivary antimicrobial agents as such has shown any strong association with caries activity. The only ones with some evidence of a regulatory role are secretory IgA antibodies, hypothiocyanite ions, and agglutinins. However, the data are controversial and it seems that instead of measuring individual parameters, the assessment of saliva's functional properties (such as the ability to aggregate bacteria, prevent their adhesion to hydroxyapatite or sugar metabolism etc.) is more important for clinical purposes. Of the parameters involved in de- and remineralization process, only salivary fluoride content has some association with caries susceptibility but its diagnostic or predictive value is questionable.

Agglutinins↗