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PubMed1991

[Personal identification from antibodies to oral streptococci using ELISA].

Serum antibodies to oral streptococci were titrated by ELISA for the purpose of personal identification. The bacteria concerned comprised 9 strains of Streptococcus mutans, which are known to cause dental caries, and one strain of Streptococcus sanguis commonly found in the oral cavity and harmless to the teeth. The quantities of IgM antibodies to these streptococci were more or less dependent on the total levels of serum IgM. However, no relation was found between the IgG antibodies and the total serum levels of IgG. IgA antibodies showed a degree of correlation that was intermediate between those of the IgM and IgG antibodies. Two antibodies, anti-Streptococcus mutans PS14 (anti-SM) and anti-Streptococcus sanguis 10556 (anti-SS), were selected, because the cross-reactivities of the IgG antibodies with these streptococci were slight. The quantity ratios of IgG anti-SM antibodies and IgG anti-SS antibodies differed from person to person, ranging from about 1:1 to 1:6 in 129 healthy Japanese adults. ELISA was considered to be appropriate for assaying these antibodies because of its good intra-assay reproducibility. The IgG anti-SM/anti-SS quantity ratio was not related to sex, age or ABO blood group, and appeared to be unrelated to the "decayed, missing and filled teeth index" (DMF index). The anti-SM/anti-SS ratios were investigated for 12 months after the preparation of bloodstains. They remained almost unchanged for 8 months, although the reactivities of individual IgG antibodies began to decrease 3 to 5 months after preparation. These results indicate that the ratio of IgG anti-streptococcal antibodies in bloodstains is a very useful parameter in personal identification.

Antibodies, Bacterial↗

PubMedDate not supplied

Joint use of clinical parameters, biological markers and CAGE questionnaire for the identification of heavy drinkers in a large population-based sample.

AIMS: Alcohol consumption in France is one of the highest in the world. Factors associated with excessive alcohol drinking are numerous. However, taken separately, none of the existing clinical or biological markers of excessive alcohol intake enables an adequate identification of heavy drinkers. The aim of this cross-sectional survey was to identify socio-demographic, clinical and biological factors associated with excessive alcohol drinking, to develop a model and to assess its reliability, thus enabling the detection of heavy drinkers. METHODS: Subjects were 1619 men and 1559 women, aged 35-64 years, living in three French areas (Lille, Strasbourg and Toulouse) and randomly selected from polling lists. Socio-demographic status, lifestyle, reported alcohol intake and answers to the CAGE questionnaire (alcohol dependence) were obtained by questionnaire. A blood sample was taken for quantification of biological parameters. Men who drank 60 g of ethanol a day (g/day) or above and women who drank 30 g/day or above were classified as heavy drinkers. The reference class (RC) gathered non-drinkers and moderate drinkers together. The sample was divided into two sub-samples: the first was used to estimate the parameters of a logistic regression model (heavy drinkers vs others), and the second to assess the accuracy of this model for the identification of heavy drinkers, using receiver operating characteristic (ROC) curves. A specific analysis was performed for each gender. RESULTS: Fourteen per cent of men and 40.8% of women were non-drinkers. Nine per cent of women and 14.4% of men were heavy drinkers. Wine was the most consumed alcoholic beverage. In the univariate analyses, differences were observed between the two groups of alcohol consumers for most of the socio-demographic, clinical and biological variables considered. In the multivariate analyses, low educational level, smoking, apoprotein B, high density lipoprotein cholesterol, mean corpuscular volume (MCV), gamma-glutamyl-transferase (GGT) and the CAGE score for men, and living area, age, MCV, GGT and the CAGE score for women remained independently and significantly associated with heavy drinking. In the validation sub-sample, these models combining different types of markers enabled a good discrimination between heavy drinkers and the RC, with an area under the ROC curve of 82% for men and of 79% for women. CONCLUSIONS: In this study, socio-demographic, clinical and biological factors and the CAGE score were independently related to excessive alcohol drinking and their joint utilization in a screening model enabled a good recognition of heavy drinkers.

Adult↗

PubMed1988

Chemiluminescence microscopy reveals functional heterogeneity in single neutrophils undergoing oxygen burst.

Activated polymorphonuclear leukocytes (PMN) respond to various triggers with an oxygen burst, during which the release of reactive oxygen species (ROS) plays a key role in microbial killing. The biological function of the ROS-associated light emissions is not known. However, this particularly weak cell-derived chemiluminescence (CL) may serve as a parameter for the identification of PMN activation. In this study we describe a novel technique which we termed CL microscopy. A microscope-based low-light image-processing system was applied which was sensitive enough to detect single photons, capable of two-dimensional signal accumulation, and digital image analysis. This technique permitted, for the first time, the visualization of the oxygen burst in single cells. Furthermore, quantitative evaluation of cell-derived luminol-enhanced CL revealed functional heterogeneity. Single-cell investigations of activated living PMN of normal human donors showed clear differences in kinetics and intensity of the oxygen burst related to different stimuli. The chemical agent (phorbol 12-myristate 13-acetate) induced CL in 83% of PMN. In contrast, the complement-mediated phagocytic stimulation by opsonized zymosan gave much higher light intensities of individual cells, but only in part of the PMN population (30%). CL microscopy presents a new and highly sensitive technique with considerable potential for single-cell analysis in immunological research.

Free Radicals↗

PubMed2001

Continuous flow stable isotope methods for study of delta(13)C fractionation during halomethane production and degradation.

Gas chromatography/mass spectrometry/isotope ratio mass spectrometry (GC/MS/IRMS) methods for delta(13)C measurement of the halomethanes CH(3)Cl, CH(3)Br, CH(3)I and methanethiol (CH(3)SH) during studies of their biological production, biological degradation, and abiotic reactions are presented. Optimisation of gas chromatographic parameters allowed the identification and quantification of CO(2), O(2), CH(3)Cl, CH(3)Br, CH(3)I and CH(3)SH from a single sample, and also the concurrent measurement of delta(13)C for each of the halomethanes and methanethiol. Precision of delta(13)C measurements for halomethane standards decreased (+/-0.3, +/-0.5 and +/-1.3 per thousand) with increasing mass (CH(3)Cl, CH(3)Br, CH(3)I, respectively). Given that carbon isotope effects during biological production, biological degradation and some chemical (abiotic) reactions can be as much as 100 per thousand, stable isotope analysis offers a precise method to study the global sources and sinks of these halogenated compounds that are of considerable importance to our understanding of stratospheric ozone destruction.

Biodegradation, Environmental↗

PubMed1991

A comparative phase II clinical trials procedure for choosing the best of three treatments.

In some clinical trials one can employ adaptive designs advantageously, although in practice such techniques are rarely used, in part due to their inherent complexity. A simple and practicable decision-theoretic approach for the case of three treatments with binary responses is considered, using equal allocation to remaining treatments and, once eliminated, a treatment cannot be re-employed. Having specified the overall number of patients treated within and beyond the comparative stages of the trial, the goal is to maximize the expected total number of those successfully treated. Investigation of the method involves a computer program that can handle arbitrarily large numbers of patients. It is shown empirically that the decision procedure behaves only marginally worse than if the truly superior treatment had been known and had been given to all patients. Implementation of the method uses a minimax approach that removes dependence on prior parameters. Primarily an identification procedure, one advantage of this approach over traditional hypothesis testing methods is the potential to detect small improvements in treatment efficacy. The intended application is to assist in treatment selection during phase II trials, especially with rapid responses and when the disease involved is serious enough that design-motivating ethical considerations become paramount.

Clinical Trials as Topic↗

PubMed1992

Modelling of in vivo calcium metabolism. II. Minimal structure or maximum dynamic diversity: the interplay of biological constraints.

The temporal behaviour of the nonlinear compartmental model we have developed for rat calcium metabolism is discussed with respect to the theoretical properties of the self-oscillating autocatalytic subunit around which the model is constructed. Depending on the approximations made, this subunit is described by a minimal two-variable model, SU2, or by a three-variable one, SU3. The diversity of the theoretical dynamic behaviours possible with SU2 is greatly increased with SU3. But the identification of SU3 parameter values in three different experimental situations reveals that biological constraints efficiently preserve a simple circadian rhythm for bone metabolism. This analysis indicates the significant contribution of the available bone crystal pool to the dynamic organization of this tissue, and hence to extracellular calcium homeostasis.

Animals↗

PubMed1993

Detection of complete and partial chromosome gains and losses by comparative genomic in situ hybridization.

Comparative genomic in situ hybridization (CGH) provides a new possibility for searching genomes for imbalanced genetic material. Labeled genomic test DNA, prepared from clinical or tumor specimens, is mixed with differently labeled control DNA prepared from cells with normal chromosome complements. The mixed probe is used for chromosomal in situ suppression (CISS) hybridization to normal metaphase spreads (CGH-metaphase spreads). Hybridized test and control DNA sequences are detected via different fluorochromes, e.g., fluorescein isothiocyanate (FITC) and tetraethylrhodamine isothiocyanate (TRITC). The ratios of FITC/TRITC fluorescence intensities for each chromosome or chromosome segment should then reflect its relative copy number in the test genome compared with the control genome, e.g., 0.5 for monosomies, 1 for disomies, 1.5 for trisomies, etc. Initially, model experiments were designed to test the accuracy of fluorescence ratio measurements on single chromosomes. DNAs from up to five human chromosome-specific plasmid libraries were labeled with biotin and digoxigenin in different hapten proportions. Probe mixtures were used for CISS hybridization to normal human metaphase spreads and detected with FITC and TRITC. An epifluorescence microscope equipped with a cooled charge coupled device (CCD) camera was used for image acquisition. Procedures for fluorescence ratio measurements were developed on the basis of commercial image analysis software. For hapten ratios 4/1, 1/1 and 1/4, fluorescence ratio values measured for individual chromosomes could be used as a single reliable parameter for chromosome identification. Our findings indicate (1) a tight correlation of fluorescence ratio values with hapten ratios, and (2) the potential of fluorescence ratio measurements for multiple color chromosome painting. Subsequently, genomic test DNAs, prepared from a patient with Down syndrome, from blood of a patient with T-cell prolymphocytic leukemia, and from cultured cells of a renal papillary carcinoma cell line, were applied in CGH experiments. As expected, significant differences in the fluorescence ratios could be measured for chromosome types present in different copy numbers in these test genomes, including a trisomy of chromosome 21, the smallest autosome of the human complement. In addition, chromosome material involved in partial gains and losses of the different tumors could be mapped to their normal chromosome counterparts in CGH-metaphase spreads. An alternative and simpler evaluation procedure based on visual inspection of CCD images of CGH-metaphase spreads also yielded consistent results from several independent observers. Pitfalls, methodological improvements, and potential applications of CGH analyses are discussed.

Aneuploidy↗

PubMed1988

CEA-containing immune complexes in sera of patients with colorectal and breast cancer--analysis of complexed immunoglobulin classes.

A sandwich enzyme immunoassay was developed to detect circulating immune complexes containing carcinoembryonic antigen (CEA) and immunoglobulin (Ig) G, IgA, or IgM using a nitrocellulose-bound anti-CEA antibody as the solid phase reagent. Elevated levels of CEA-containing circulating immune complexes (CEA-IC) were found in 15.4% of 117 sera from patients with colorectal cancer in a postsurgery follow-up study. Also in 24.5% of 102 sera from patients with breast cancer in different states of disease CEA-IC were found. The predominant Ig determined in CEA-IC of colorectal cancer patients was IgA, followed by IgG and IgM, whereas IgG and IgM were the most frequent Igs in CEA-IC of breast cancer patients. Elevated CEA levels were found in 12.0% of the colorectal cancer patients and in 25.4% of sera from breast cancer patients. No significance for the coincidence of elevated CEA levels and CEA-IC was recorded in all patients sera tested. In sera of patients with disease recurrence, however, both parameters were shown to be elevated (CEA 80.7% and CEA-IC 42.3%). The data presented indicate the detection of CEA-IC as an additional parameter for the identification of patients at increased risk for disease recurrence.

Antigen-Antibody Complex↗

PubMed1998

[Immunologic foundations of new vaccination strategies].

Vaccines provide cost-efficient means for control of infectious diseases. Yet, several infectious diseases exist, for which efficacious vaccines are not available, as yet. Recent progress in immunology has led to the identification of the parameters which promote the development of the most appropriate immune response that develops against a given infectious agent. Major criteria are the conditions of intracellular antigen processing which regulate activation of CD4 or CD8 T-cells. CD4 T-cells play a major role in the control of intracellular bacteria, protozoa and fungi, and CD8 T-cells are of importance for combat of viruses and certain intracellular microbes that evade from the phagosome into the cytoplasm. Equally important are the conditions which dictate the development of T-cell populations secreting distinct cytokine patterns of Th1 or Th2 type with Th1 cells being responsible for combat of intracellular bacteria and Th2 cells playing a major role in the control of helminth infections. Understanding how the host regulates the development of the most appropriate defence mechanisms together with modern insights into molecular genetics for manipulation of microbial agents will promote the development of a novel generation of vaccines. Such vaccines will not only contribute to control of infectious agents, but also allow novel strategies towards therapy of tumors, autoimmune disease and allergy.

CD4-Positive T-Lymphocytes↗

PubMed2002

A discrete, size-structured model of phytoplankton growth in the chemostat: introduction of inhomogeneous cell division size.

We introduce inhomogeneous, substrate dependent cell division in a time discrete, nonlinear matrix model of size-structured population growth in the chemostat, first introduced by Gage et al. [8] and later analysed by Smith [13]. We show that mass conservation is verified, and conclude that our system admits one non zero globally stable equilibrium, which we express explicitly. Then we run numerical simulations of the system, and compare the predictions of the model to data related to phytoplankton growth, whose obtention we discuss. We end with the identification of several parameters of the system.

Animals↗

PubMed1988

Hungry bone syndrome: clinical and biochemical predictors of its occurrence after parathyroid surgery.

The hospital course of 218 consecutive patients with primary hyperparathyroidism admitted over a three-year period for parathyroidectomy at the Massachusetts General Hospital was reviewed to determine the incidence and identify the risk factors for the development of the hungry bone syndrome. Twenty-five patients with the hungry bone syndrome were identified (12.6 percent). Compared to patients with uncomplicated metabolic responses to parathyroid surgery, these patients were older by a mean of 10 years; they had higher preoperative serum levels of calcium, alkaline phosphatase, N-terminal parathyroid hormone, and blood urea nitrogen; and their resected parathyroid adenomata were larger. The mean duration of hospitalization averaged three days longer in the group with hungry bone disease. Stepwise multivariate analysis of preoperative variables enabled the development of a discriminant function for prediction of postoperative hypocalcemia and hypophosphatemia. Identified predictive variables were volume of resected parathyroid adenoma, blood urea nitrogen, alkaline phosphatase, and age. When validated on an independent patient population, these readily obtainable preoperative clinical and laboratory parameters will allow identification of a subgroup of patients who are at greater risk for the development of the hungry bone syndrome following parathyroid surgery.

Adenoma↗

PubMed1975

Expansion of intravascular volume and fetal outcome in patients with chronic hypertension and pregnancy.

Measurements of blood volume were carried out between 24 and 40 weeks of gestation in 20 multiparous patients with chronic hypertension and pregnancy. Hypertensive patients had both reduced blood volume and infants of smaller weight (p less than 0.01) than nonhypertensive control subjects. There was a significant difference (p less than 0.01) in the degree of blood volume expansion in hypertensive mothers who were delivered of infants who were adequate for gestational age (AGA), term, or premature, compared to those who were delivered of infants who were small for gestational age (SGA) or stillborn. Classification of chronic hypertension during pregnancy according to the American Committee on Maternal Welfare classification or according to severity of the hypertension was of no value in identifying the mothers at risk of delivering intrauterine growth-retarded infants. However, failure in achieving a blood volume expansion of at least 60 c.c. per kilogram clearly identified those pregnancies leading to growth retardation and fetal death. The decrease or lack of intravascular volume expansion was reflected in the presence of creatinine clearance values at nonpregnant levels in the mothers who were delivered of SGA infants and in a significant reduction below the nonpregnant levels in those who were delivered of stillborn infants. These data suggest that measurement of blood volume and endogenous creatinine clearance in patients with chronic hypertension and pregnancy is a useful parameter in the identification of those patients who will have a poor fetal outcome.

Blood Volume↗

PubMed1982

Risk factors for the development of distant metastases in patients undergoing pelvic lymphadenectomy for prostatic cancer.

Sixty-two patients with clinically localised prostatic cancer underwent pelvic lymphadenectomy between 1972 and 1975. Thirty-one patients had concomitant total prostatectomy. The objectives of this study included determination of the relation of findings at lymphadenectomy, with and without total prostatectomy, to subsequent clinical course, identification of histologic parameters related to the subsequent appearance of distant metastatic disease, and determination of the vital status of patients initially having a staging pelvic lymphadenectomy. Follow-up of at least 5 years was obtained for 52 patients, including 28 who had concomitant total prostatectomy. Ten patients were lost to follow-up. Fifty-four percent are alive with metastatic disease 10 percent have died with metastatic disease, 10 percent have died with metastatic cancer, and 12 percent have died without prostate cancer. Metastases have developed in 11 (37 percent) of 30 patients with negative pelvic lymph nodes, reflecting either seminal vesicle or transcapsular invasion. Minimal lymph node involvement (one or two pelvic nodes) alone may not be as poor a prognostic sign as originally thought. Metastases have developed in 22 percent of nine patients with tumor considered stage B2. No recurrences or metastases were noted in the seven patients with stage B1 disease. Patients with high grade lesions were at no increased risk for distant metastases, although they constituted a relatively small segment of our series. Thus the extent of local disease correlates with the subsequent development of distant metastasis. Adjuvant systemic treatment (endocrine manipulation, chemotherapy, or both) has a rational basis in patients with one or more of these identifiable risk factors.

Adenocarcinoma↗

PubMed1982

Tryptic peptide map analysis of the major human blood platelet membrane glycoproteins separated by two-dimensional polyacrylamide gel electrophoresis.

Washed platelets were surface-labelled by lactoperoxidase catalyzed iodination and either the platelets or membranes were solubilized in detergent and applied to a wheat germ agglutinin-Sepharose column and a Lens culinaris lectin Sepharose column coupled sequentially. The glycoproteins eluted from the lectin columns were separated by two-dimensional gel electrophoresis. Alternatively, labelled whole platelets or membranes were solubilized and then directly separated by two-dimensional polyacrylamide gel electrophoresis. Spots corresponding to specific glycoproteins identified by apparent isoelectric point (pI), apparent molecular weight (Mr), staining and labelling characteristics were cut from the gels and analyzed by tryptic peptide mapping. The maps of the individual glycoproteins(GP) Ia, Ib, IIa, IIb, GP4-4.5 132-135, IIIa, IIIb and IIIc were all different. Glycoproteins with the same Mr but different pI were distinct with the exception of regions of GP Ib. There were minor differences in the maps of glycoproteins separated in the reduced or non-reduced state. Tryptic peptide maps provide a valuable additional parameter for the identification and characterization of platelet glycoproteins.

Blood Platelets↗

PubMed1996

Evaluation of the tracking potential of a noninvasive estimator of cardiac output.

A robust, automatic measurement system for calculating cardiac output noninvasively has recently been developed. The proposed method relies on fast Fourier transform (FFT) analysis of pulses measured externally at the carotid and femoral pressure points. A transfer function of the aorta is computed from these (calibrated) pressure measurements, and a tapered model of the aorta is parametrically adapted so that its transfer function matches that derived experimentally. Incorporated in the system are a custom routine for digitally filtering pressure data and a simplex optimization algorithm for identification of aortic parameters essential to the calculation of impedance and aortic flow. Once flow has been reconstructed in the time domain it is averaged to a stroke volume and multiplied by the heart rate to yield cardiac output. Flow measurements are computed over several pulses and compared against the standard, invasive procedure of thermodilution. Preliminary results for a dynamic investigation of the method indicate a strong potential for tracking changes in cardiac output over time, thus advocating its use in monitoring hemodynamically unstable patients.

Algorithms↗

PubMed1976

Numerical determination of intestinal membrane diffusing constants by a gradient method.

Optimisation problems arising in the identification of kinetic parameters of intestinal membranes are here considered. The dynamic behaviour of the membrane is described by means of a linear compartmental model. Using optimisation techniques of a gradient type, the intestinal kinetic parameters are identified, minimising a quadratic criterion between experimental data of D-histidine transport and model prediction. Numerical results are reported and their physiological implications discussed. The quantitative assessment of the asymmetry of diffusion constants with respect to diffusion direction seems to be an important result of this work.

Biological Transport↗

PubMed1993

A three compartment open model with two time lags.

The present study deals with the identification of exchange parameters involved in a three-compartment open model with two time lags in which elimination occurs from the central compartment. Two different optimization methods have been used which involve the reduction of different unknowns to a single variable theta, with the help of Archimedes Spiral. Thus, the solution requires the global minimum of a functional of single variable theta. Results are compared with those obtained by the generalized least square method.

Absorption↗

PubMed1993

A four compartment open model with first-order absorption.

This paper is related to the identification of pharmacokinetic parameters of a four-compartment open model with first order absorption from plasma level data. The eigenvalues of the characteristic matrix of the given system are obtained by transforming them into a single variable and the solution involves the minimization of the sum of squares of deviation of the model-predicted values of the state variables from an experimentally obtained values. The distribution volume and the lag time are also identified. Finally, the unicity of the absorption rate constant is obtained by the minimum energy principle. The results obtained with present method are compared with those obtained by the generalized least squares method.

Absorption↗