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PubMedDate not supplied

Microbiological reference values for foods: a European perspective.

Microbiological criteria for food products and meals serve to gauge the results obtained upon monitoring samples from manufacturing plants or catering units which strictly adhere to good manufacturing practices (GMP). Hazardous practices thus already having been eliminated, the aim of monitoring is to detect and, above all, immediately correct accidental failures in processing or preparation. An essential element of this system of monitoring is that the number of criteria used is kept to a minimum by carefully selecting the criteria of major ecological significance. In view of the sporadic and erratic distribution of pathogenic organisms in foods from well-run manufacturing plants and food service operations, criteria for disease agents are used only occasionally. Where they are used, their selection and detection methodology require intensive and expert scrutiny, including (i) careful designation and precise definition of the relevant agents of disease, toxin formers, or preformed toxins; (ii) prescription of very carefully validated and standardized methods, usually including a resuscitation step; and (iii) mathematically correct interpretation of failure to detect particular infectious or toxinogenic organisms. On the other hand, "marker" organisms ("indicator" and "index" organisms, according to Ingram) are frequently used. These should also be carefully selected by ecological surveys on each specific food product; in particular, their value for reliably revealing deficiencies in hygiene or handling should be assessed. The applicability of the entire group of Enterobacteriaceae (or particular parts of that taxon), Enterococcus species, Staphylococcus aureus, and streptococci of the "mitis-salivarius" group are critically examined. Numerical reference values for microbiological criteria are derived by mathematical treatment from data obtained in surveys of products produced under GMP previously validated by safety analysis. Target values thus derived will include tolerance limits and policies recommended in case high results are obtained. Consequently, "3-class sampling plans" (according to ICMSF) are to be used in most instances.

Bacteria↗
PubMed2005

Serum cystatin C in pregnant women: reference values, reliable and superior diagnostic accuracy.

BACKGROUND: A simple, endogenous, accurate and minimally invasive marker of glomerular filtration rate (GFR) is much desired in clinical nephrology. Cystatin C fulfills all criteria to be a marker for GFR. For early detection of renal impairment in pregnant women, it is necessary to determine serum cystatin C reference values and the correlation with GFR. The present study was therefore undertaken. METHOD: Healthy pregnant women were followed during pregnancy and the postnatal period. Patient demographics included age, height, weight, BMI, parity, total blood count, LFT, urea, creatinine, Na, K, and blood sugar. Serum cystatin C was estimated using particle enhanced nephlo-immunoassay method. All the parameters were recorded at the start of pregnancy and then in each trimester and the postnatal period. Regression analysis correlation coefficient, ANOVA and the Student's t-test were used for analysis using the SPSS statistical package. RESULTS: A total of 197 pregnant women were included. Mean serum cystatin C for all the women was 0.82 +/- 0.184 mg/l. Serum cystatin C levels were high -0.89 +/- 0.12 mg/l in the first trimester, decreased significantly to 0.651 +/- 0.14 mg/l during the second trimester (p = 0.0000 compared to first trimester), and increased again to 0.82 +/- 0.191 mg/l in the third trimester. After delivery the level rose to 0.94 +/- 0.12 mg/l. A strong correlation was found between serum cystatin C and serum creatinine. A strong negative correlation was found between GFR and cystatin C values in the women (r = -0.546, p = 0.000). A linear relationship was found between GFR and cystatin C levels. A significant increase in the GFR was noted with the progression of pregnancy from 128.06 +/- 29.7 ml/min in the first trimester to 155.2 +/- 29.59 ml/min during second trimester (p = 0.006). A decline in the level of cystatin C exactly parallel to the increase in the GFR was noted with the progression of pregnancy. Interestingly cystatin C was found to have a strong negative correlation with gestational age (r = -0.663, p = 0.000). CONCLUSION: Our results indicate that the mean serum cystatin C levels reflect changes in the GFR during the entire pregnancy and also in the postnatal period. Moreover, serum cystatin C levels are independent of age, height, weight, or blood sugar level. Cystatin C can be used for close supervision and early diagnosis of renal impairment in pregnant patients. Cystatin C is a reliable, useful and promising marker of GFR in pregnant women.

Adolescent↗
PubMed1999

Cystatin C in healthy women at term pregnancy and in their infant newborns: relationship between maternal and neonatal serum levels and reference values.

Human cystatin C, a basic low molecular mass protein with 120 amino acid residues, is freely filtered by the glomerulus and almost completely reabsorbed and catabolized by the proximal tubular cells. Cystatin C has been recently proposed as a new sensitive endogenous serum marker for the early assessment of changes in the glomerular filtration rate. To define a reference basis for future clinical investigations in the perinatal period, we investigated the relationship between maternal and neonatal serum cystatin C in comparison with that of creatinine. We also defined reference values in healthy women at full-term pregnancy and in full-term newborns over the first 5 days of life. Seventy-eight women with uncomplicated pregnancy, aged between 19 and 40 years, and their infant newborns (43 males, 35 females) were enrolled in the study. The gestational age ranged from 37 to 43 weeks, and the birth weight from 2.50 to 4.15 kg. Blood samples were taken from all the women immediately before delivery and from their newborns at birth, 72 and 96 h after birth. Maternal and neonatal renal function was evaluated by standards parameters and by calculating creatinine clearance. In all serum samples, we measured cystatin C, creatinine, and urea. At term gestation, serum cystatin C ranged from 0.64 to 2.30 mg/L. At birth, serum cystatin C values ranged from 1.17 to 3.06 mg/L, significantly decreasing after 3 and 5 days of life. No correlation was found between maternal and neonatal serum cystatin C values (r = 0.09). As cystatin C serum levels in newborns are not significantly correlated with the respective maternal levels, neonatal serum cystatin C may originate almost exclusively in the neonate.

Adult↗
PubMed1995

[Cytologic and biochemical component in 203 bronchoalveolar lavages. Reference values].

The bronchoalveolar lavage (BAL) is considered a basic technique as a diagnostic aid in Pneumology. However, one of the main problems faced by the clinician is the lack of standardization of the technique. This has been resolved through the drafting of international standards. The other problem is the lack of what might be called a "reference" BAL. In order to establish a reference BAL, we analyzed 203 BAL divided in two groups: a control group and a pathologic group, make up by extrinsic asthma, intrinsic asthma, pulmonary infections, diffuse interstitial pneumopathies, bronchopulmonary tumors and chronic bronchitis. We have studied both the cytologic and the biochemical component of the BAL. Among the biochemical markers, we have considered; carcinoembrionary antigen (CEA), tissular polypeptidic antigen (TPA), neuronal specific enolase (NSE), ferritin (FER), calcitonin (CT), ACTH, histamin (HIS) and prostaglandin (PGE2). In order to establish the reference values, we have used the modified Baye's theorema. The BAL that we obtained was the following: volume 20 ml, cells 35 x 10(5) cells/ml, macrophages 77%, lymphocytes 22%, neutrophils 4%, eosinophils 2%, CEA 14 ng/mg, TPA 84 U/g PT, NSE 5 ng/mg PT, FER 42 ng/mg PT, CT 15 pg/mg PT, ACTH 51 pg/mg PT, HIS 1.22 ng/mg PT, PGE2 35 pg/mg PT.

Adolescent↗
PubMed1982

Population-based reference values for lecithin-cholesterol acyltransferase (LCAT).

Plasma unesterified cholesterol is converted to cholesteryl ester by the enzyme lecithin-cholesterol acyltransferase (LCAT). Plasma levels of LCAT were measured by a sensitive double antibody radioimmunoassay in a sample from an adult employee population, ages 20-59 years, in the Pacific Northwest. After adjusting for differences in relative body mass, women had significantly higher LCAT levels (5.90 +/- 1.06, n = 154) than men (5.49 +/- 0.89, n = 83). For ages 20-59 years, LCAT levels showed a slight association with age: r = 0.13 for men and 0.29 for women. LCAT was positively correlated with relative body mass, total cholesterol, and LDL cholesterol. Men who smoked cigarettes had significantly lower LCAT mass than men who did not smoke cigarettes. No statistical differences in mean LCAT values were found between drinkers and nondrinkers. The 5th percentile LCAT value was 4.3 micrograms/ml for both men and women not using hormones. The 95th percentile value was 7.3 micrograms/ml for men and 7.8 micrograms/ml for women regardless of hormone use. Subjects phenotypically LCAT-deficient by clinical criteria and by the absence or near absence of LCAT activity had levels of LCAT mass well below the reference values: 0.73 +/- 0.70, range 0.10 micrograms/ml to 2.65 micrograms/ml, n = 20. Parents or children of LCAT-deficient subjects, i.e., obligate heterozygotes for familial LCAT deficiency, had reduced levels: 3.59 +/- 0.69, range 2.59-4.61 micrograms/ml, n = 19.

Adult↗
PubMed2003

Persisting challenges in plasma endocrinology: reference values and endocrine tests.

The analysis of plasma hormone concentrations is of fundamental importance for the diagnosis and treatment of endocrine diseases. Although hormone analyses are performed in huge numbers in all hospitals on a daily basis, the interpretation of the resulting plasma hormone concentrations can be difficult. In addition to the effects of the underlying disease, biological and analytical issues affect hormone concentrations. Therefore, adequate reference values and strict standardisation of sampling and analytical procedures are very important for the final interpretation of the results of hormone analysis.

Diagnostic Techniques, Endocrine↗
PubMed1992

[The significance and use of somatometric reference values of weight and height in pediatric and epidemiologic practice].

If we know growth as cellular phenomenon to addition of matter to protoplasm, is valid how a generic phenomenon, within normality range, is a species attribute, and in the human would be of psychosocial order. It is a appointed with only somatometrie is not valid criterion in the diagnosis of desnutrition, but is a excellent point in order to identification of risk population. In this order is necessary reference values useful, well elaborated, with adequate samples. It is commented about weight and height as a adequate parameters for measuring growth. It is convenient the adoption of an unique international somatometric reference tables if we considered growth how a generic and species phenomenons. Were analyzed 2 works of reference tables used in our country. Finally is commented the convenience of use of an unique international reference tables. It is proposed the somatometric reference tables published for the WHO, in 1983, and were discussed the razons for this recommendation.

Adolescent↗
PubMed1992

[Evaluation of an immunoenzymatic method for determining TSH and establishment of reference values].

In the present work we reported the results of the valuation of IMx Ultrasensitive hTSH assay which is a Microparticle Enzyme ImmunoAssay (MEIA) for quantitative determination of human stimulating hormone (hTSH) in the human serum or plasma. We have determined the method's precision, within run and between run, sensitivity and recovery. This method has been compared with another one (Immuno RadioMetric Assay). Also reference values have been calculated in the "normal" male and female population and shortly commented.

Antibodies, Monoclonal↗
PubMed1993

International project for producing reference values for concentrations of trace elements in human blood and urine--TRACY.

In assessing the concentrations of toxic metals, such as cadmium, chromium, and mercury, in human blood and urine samples to determine whether they are abnormal or not, reliable reference values are needed from populations of nonoccupationally exposed subjects. Numerous publications present concentrations claimed to be typical for the study populations, but they can differ by up to an order of magnitude for a particular element. This is the consequence of general problems that are related to the definition of the reference groups, and the sampling and analytical procedures used, and that make it difficult to define typical and unbiased values. An international group of experts now establishes criteria and procedures to evaluate publications containing information on the concentrations of metals in tissues and body fluids for reference populations. These evaluations have been compiled in a data base (TRACY).

Hazardous Substances↗
PubMed1994

Tentative reference values for nickel concentrations in human serum, plasma, blood, and urine: evaluation according to the TRACY protocol.

Published reports of Ni concentrations in human serum or plasma, whole blood, and urine have been reviewed in order to establish a database of reference values. In keeping with the TRACY program as previously applied to Hg, reports were evaluated in the categories of description of sample population, specimen collection and processing, analytical methods, and data presentation. Based on these considerations, eight studies of Ni in serum were deemed suitable for establishing reference levels in the general population. In five of these studies, the mean values for serum Ni concentration were < 0.3 microgram/l and the upper limits were < or = 1.1 micrograms/l. Six studies of Ni in urine were found suitable, and in four of these the mean values of Ni were < or = 2.0 micrograms/l and the upper limits were < or = 6.0 micrograms/l. Fewer studies on Ni in whole blood have been reported, and the Ni content of blood remains uncertain.

Humans↗
PubMed1987

Reference values for peripheral blood lymphocytes from Aotus lemurinus ssp. griseimembra (owl monkey).

The reactivities of several monoclonal antibodies that define human lymphocyte cell-surface antigens have been tested with peripheral blood lymphocytes of Aotus lemurinus ssp. griseimembra. Based on reactivity patterns in humans, reactive MoAb were identified that mark pan-T, helper/inducer, suppressor/cytotoxic, pan-B, and natural killer cells. Reference values of these subsets in Aotus are presented. These MoAb should provide a useful tool for further phenotypic and functional dissection of the immune system in this simian model of human disease.

Animals↗
PubMed2005

[Analysis of reference values of serum S100B concentrations of Japanese adults].

PURPOSE: S100B is a calcium-binding protein which exists in abundance in glial cells of the central nervous system (CNS). It is reported that the serum S100B level increase with various CNS diseases, such as stroke, head injury, schizophrenia, major depression and Alzheimer's disease. However, there are no reports on its reference values for the Japanese. The purpose of this study is to know the serum S100B concentrations of Japanese adults, free of any CNS diseases, according to sex, age and circadian rhythm. Moreover, the stability and reproducibility of its measurements of S100B in frozen serum over 7 months. METHODS: Volunteers were 26 male and 25 female of Japanese adults. Venous blood samples were collected at given times of a day and serum was obtained by centrifugation at 4 degrees C. An automated chemiluminescence analyzer "LIAISON" and exclusive reagent Sangtec 100 (DiaSorin, Italy), was used for measurement of serum S100B concentrations. RESULTS: The serum S100B concentrations in Japanese adults corresponded well, with the reported values in Asians. Differences by age and sex were not found. S100B did not how circadian variation. The serum S100B concentrations measured in two months and in nine months after venipuncture were almost the same. CONCLUSION: The measurement of S100B by "LIAISON" showed excellent reproducibility and reliability. Furthermore, stability of serum S100B stored at -80 degrees C was good.

Adult↗
PubMedDate not supplied

Forced oscillation technique. Reference values for resistance and reactance over a frequency spectrum of 2-26 Hz in healthy children aged 2.3-12.5 years.

The forced pseudo-random noise oscillation technique is a method by which total respiratory resistance (Rrs) and reactance (Xrs) can be measured simultaneously at various frequencies by means of complex oscillations, superimposed at the mouth during spontaneous quiet breathing. Reference values were obtained in 255 healthy Caucasian children of Dutch descent aged 2.3-12.5 years. Rrs and Xrs vs frequency (f) curves are mainly determined by the child's sex, age, height and weight. Taking complete Rrs and Xrs-f curves into account, we found that Rrs values were significantly higher in young boys than in young girls. They were equal at about 8 years, but at about 12 years of age Rrs values were again significantly higher in boys than in girls. Frequency dependence of Rrs was found in healthy boys up to about 5 years of age, but not in girls of the same age or in older children. These data suggest differences in airway diameter between boys and girls. At all ages Xrs was significantly lower in boys than in girls. This suggests differences in bronchial patency of peripheral airways, boys being at a disadvantage. It is concluded that multiple frequency oscillometry is a method which is ideal for children from the age of about 3 years. The possibility of measuring Rrs as well as frequency dependence of Rrs and Xrs simultaneously is the major advantage over other oscillation devices.

Adolescent↗
PubMed1991

Placental morphometry using a computer assisted measuring programme: reference values for normal pregnancies at term.

Using the principle that the human placenta is anatomically composed of fetomaternal flow units, we developed a computer-assisted measurement programme capable of recording complex histometric data about the characteristics of the maturation and structural differentiation of resorption villi, as well as subjecting the results to simultaneous statistical processing. Using 42 placentas obtained after normal pregnancies, reference values were derived for the five primary geometrical and six further arithmetical parameters. From these findings, we also calculated the total resorption villi surface area, the proportion of this surface area occupied by epithelial plates, and the resorption-villi surface are relative to the birth weight of the child. Our findings are compared with other available results, and the reasons for discrepancies between previously published measurements are discussed.

Birth Weight↗
PubMed1994

[Reference values for blood, hair, and organ selenium levels in adults of Beijing].

Two hundred and four blood specimens and 202 hair specimens, and 72 tissue specimens of heart, liver, spleen, lung, kidney, muscle and skeleton from adults living in Beijing suddenly died were collected during 1990-1991. Selenium levels were determined by 2,3-diamine naphthalene fluorescence method with serum, human hair and calf liver as standard references to assure the quality of determination, and their reference values for adults in Beijing were established. Selenium nutritional status of the adults was evaluated preliminarily. Dietary selenium intake was estimated based on serum selenium levels, and the body total selenium content was estimated by biological monitoring.

Adolescent↗
PubMed1994

Estimation of the geometric means and the reference values of blood lead levels among Koreans.

Blood lead concentrations of Koreans who have not been exposed to lead occupationally, show a wide range of variation. Despite the fact that blood lead concentration reveals a long-normal distribution, geometric means and standard deviations have not been presented in almost all studies on blood lead levels in Koreans. A new meta-analytical method was applied to estimate the theoretical geometric means, the standard deviations of the logarithm, and the reference values of blood lead concentrations among Koreans based on arithmetic means and standard deviations reported, and to compare them to those of other countries. Estimated geometric means of Korean men, women, and men and women, were 18.03, 13.13, and 15.80 micrograms/dl, respectively. Values of 90, 95, and 99 percentile for Korean men were 31.81, 37.36, and 50.52 micrograms/dl, for women, 28.41, 35.34, and 53.24 micrograms/dl, and for men and women, 31.42 micrograms/dl, 38.17 micrograms/dl, and 54.95 micrograms/dl, respectively. These values are higher than those of neighboring countries, such as China and Japan.

Environmental Exposure↗
PubMedDate not supplied

[Polychlorobiphenyls: reference values].

The purpose of this work is to compare the PCB values in blood, serum and adipose tissue of non-exposed people over the last twenty years of scientific literature in order to establish whether the determination of single congeners is better then the evaluation of the total PCB amount moreover an analytical strategy useful to define a reference value for non-exposed Italian population has been evaluated. In the literature very variable results were found for the determination of total PCBs in blood, in serum or adipose tissue. We suggest to determine only the amount of the most toxic congeners of PCBs (28, 52, 77, 101, 118, 126, 138, 153, 169, 180) by using the HRGC/ECD as analytical technique.

Humans↗