Comparison of a guaiac and an immunochemical faecal occult blood test for the detection of colonic lesions according to lesion type and location.

We investigated variations in sensitivity of an immunochemical (I-FOBT) and a guaiac (G-FOBT) faecal occult blood test according to type and location of lesions in an average-risk 50- to 74-year-old population. Screening for colorectal cancer by both non-rehydrated Haemoccult II G-FOBT and Magstream I-FOBT was proposed to a sample of 20 322 subjects. Of the 1615 subjects with at least one positive test, colonoscopy results were available for 1277. A total of 43 invasive cancers and 270 high-risk adenomas were detected. The gain in sensitivity associated with the I-FOBT was calculated using the ratio of sensitivities (RSN) according to type and location of lesions, and amount of bleeding. The gain in sensitivity by using I-FOBT increased from invasive cancers (RSN=1.48 (1.16-4.59)) to high-risk adenomas (RSN=3.32 (2.70-4.07)), and was inversely related to the amount of bleeding. Among cancers, the gain in sensitivity was confined to rectal cancer (RSN=2.09 (1.36-3.20)) and concerned good prognosis cancers, because they involve less bleeding. Among high-risk adenomas, the gain in sensitivity was similar whatever the location. This study suggests that the gain in sensitivity by using an I-FOBT instead of a G-FOBT greatly depends on the location of lesions and the amount of bleeding. Concerning cancer, the gain seems to be confined to rectal cancer.

Comparison of a guaiac based and an immunochemical faecal occult blood test in screening for colorectal cancer in a general average risk population.

BACKGROUND: The guaiac faecal occult blood test (G-FOBT) is recommended as a screening test for colorectal cancer but its low sensitivity has prevented its use throughout the world. METHODS: We compared the performances of the reference G-FOBT (non-rehydrated Hemoccult II test) and the immunochemical faecal occult blood test (I-FOBT) using different positivity cut-off values in an average risk population sample of 10,673 patients who completed the two tests. Patients with at least one test positive were asked to undergo colonoscopy. RESULTS: Using the usual cut-off point of 20 ng/ml haemoglobin, the gain in sensitivity associated with the use of I-FOBT (50% increase for cancer and 256% increase for high risk adenoma) was balanced by a decrease in specificity. The number of extra false positive results associated with the detection of one extra advanced neoplasia (cancer or high risk adenoma) was 2.17 (95% confidence interval 1.65-2.85). With a threshold of 50 ng/ml, I-FOBT detected more than twice as many advanced neoplasias as the G-FOBT (ratio of sensitivity = 2.33) without any loss in specificity (ratio of false positive rate = 0.99). With a threshold of 75 ng/ml, associated with a similar positivity rate to G-FOBT (2.4%), the use of I-FOBT allowed a gain in sensitivity of 90% and a decrease in the false positive rate of 33% for advanced neoplasia. CONCLUSIONS: Evidence in favour of the substitution of G-FOBT by I-FOBT is increasing, the gain being more important for high risk adenomas than for cancers. The automated reading technology allows choice of the positivity rate associated with an ideal balance between sensitivity and specificity.

Serum amylase and lipase activities in normal pregnancy: a prospective case-control study.

OBJECTIVE: The diagnosis of acute pancreatitis during pregnancy is usually based on the association of upper abdominal pain, nausea or vomiting, and elevated serum amylase or lipase activities. The changes in these enzymatic activities have not been clearly established during normal pregnancy. The aim of this study was therefore to evaluate serum amylase and lipase activities in healthy pregnant women. METHODS: Serum amylase and lipase activities were measured in 103 pregnant women (first trimester, n = 34; second trimester, n = 36; third trimester, n = 33) and in 103 nonpregnant women matched for age and not receiving oral contraception. RESULTS: Serum amylase activity was similar in pregnant women and nonpregnant women during all trimesters of pregnancy. Serum lipase activity was significantly lower during the first trimester of pregnancy compared to nonpregnant women (48.6+/-27.6 vs 59.2+/-29.3 IU/L, p < 0.05) and compared to the third trimester (48.6+/-27.6 vs 76.3+/-35.8 IU/L, p < 0.001). Serum lipase activity was not statistically different between pregnant and nonpregnant women during the second and third trimesters. CONCLUSION: An increase in serum amylase and lipase activities during pregnancy should be taken into account, as in nonpregnant women.

Sex differences in the control of sex-hormone-binding globulin in the elderly: role of insulin-like growth factor-I and insulin.

OBJECTIVE: Serum levels of sex-hormone-binding globulin (SHBG) have been reported in the literature to increase with age in both sexes. We have investigated the variations in levels of androgens, insulin and IGF-I with age and have evaluated their putative roles to obtain a better understanding of the increase in SHBG. DESIGN: Cross-sectional pilot study of blood samples in healthy elderly subjects aged 50 to 90 years. PATIENTS AND METHODS: Forty-four postmenopausal women and 40 men were classified into three age groups. Subjects who were obese, undernourished or smokers and postmenopausal women receiving hormone replacement therapy were excluded from the study. Body mass index and waist/hip ratio were evaluated in each subject. Fasting levels of blood glucose, insulin, triglycerides, cholesterol, SHBG, testosterone, dehydroepiandrosterone sulfate (DHEAS) and IGF-I were measured. Free testosterone and glucose/insulin ratio were calculated. RESULTS: The results are based on variance analysis of the mean of each parameter in the three age groups. Multiple regression analysis was performed to define the role of age, insulin and IGF-I in the increase in SHBG. The increase in SHBG with age in older men was significant but that in postmenopausal women was not. Decreasing DHEAS with age was confirmed. No significant variations in glucose and insulin were observed with age in our selected population. A positive correlation was observed between insulin and triglycerides in elderly men and women. IGF-I decreased significantly with age in both sexes. Insulin was the main factor explaining SHBG increase with age in women. In men, both age and IGF-I contributed to the SHBG increase. CONCLUSIONS: The factors regulating the increase in SHBG with age appear to be different in the two sexes. Insulin plays a major role in women, whereas a decrease in IGF-I is the predominant regulating factor in men. These results should be thought of as a working hypothesis rather than a reflection of physiology.

Hepatitis C in a French population-based survey, 1994: seroprevalence, frequency of viremia, genotype distribution, and risk factors. The Collaborative Study Group.

The aims of this study were the following: 1) to estimate the prevalence of hepatitis C virus (HCV) antibody (anti-HCV) in a population-based survey of French residents not selected for risk factors; 2) to investigate the association between anti-HCV seropositivity, viremia, the infecting HCV genotype, and the alanine transaminase (ALT) level; and 3) to identify risk factors for HCV infection by a nested case control study within this survey sample. The anti-HCV seroprevalence survey was performed in 6,283 volunteers (20- to 59-years-old) randomly selected from 45,377 consecutive individuals undergoing routine medical checkup in social security medical centers covering 4 of the 22 "regions" of France. Seventy-two volunteers were anti-HCV positive, a crude prevalence of 1.15%. Fifty percent of these positive volunteers also had an abnormal ALT level and 81% were HCV-RNA positive by polymerase chain reaction (PCR). The prevalence weighted for age, sex, and place of residence was 1.05% (95% CI: 0.75-1.34). The weighted prevalence was lower among men > 40-years-old (0.5%; 95% CI: 0.1-1.0) and was close to 1% in all other age and sex groups. Prevalence was inversely correlated with socioprofessional status with the highest rate being found among those with no paid employment (2.2%; 95% CI: 1.3-3.0). The HCV prevalence (1.7%; 95% CI: 1.0-2.3) was highest in southeastern France. Seventy-eight percent of positive intervenous (I.V.) drug abusers were infected with HCV genotypes 1a or 3, whereas 80% of the transfusion-associated cases were infected by HCV genotypes 1b or 2a. Only three variables were significantly associated with HCV seropositivity in multivariate analysis: I.V. drug abuse (21 cases, 14 men all < 40-years-old), previous transfusion (22 cases, 18 women), and not having paid employment. Although routes of transmission other than I.V. drug abuse and transfusion may not be formally excluded they were not found to be statistically significant. Hepatitis C appears to be a major public health concern in France. A more active screening policy may be required because only 17 of 72 cases (24%) were aware of their HCV seropositivity before enrollment in the study.

Liver function tests in normal pregnancy: a prospective study of 103 pregnant women and 103 matched controls.

Except for increased serum alkaline phosphatase (AP) levels, the changes in liver function test (LFT) values during normal pregnancy have not been clearly established, mainly because most studies do not include matched controls. We therefore measured the serum values of routine liver tests including 5'-nucleotidase and total bile acids in 103 healthy pregnant women (first trimester, n = 34; second trimester, n = 36; third trimester, n = 33) and in 103 age-matched controls not receiving oral contraception. Fasting blood samples were taken. Because of hemodilution, serum albumin levels were significantly lower during all trimesters. As expected, AP activity was significantly higher in the third trimester. Serum aspartate transaminase (AST) activity and total bile acid (TBA) concentrations did not differ between pregnant and nonpregnant women. Serum alanine transaminase (ALT) activity was slightly higher in the second-trimester pregnant women than in controls (6.8 +/- 4.5 vs. 8.2 +/- 5.8, P = .04), although all values remained within normal limits. In pregnant women, total and free bilirubin concentrations were significantly lower during all three trimesters, as was conjugated bilirubin during the second and third trimesters. Serum gamma-glutamyl transpeptidase (GGT) activity was significantly lower in the second and third trimesters. Serum 5'-nucleotidase activity was slightly but significantly higher in the second and third trimesters. The knowledge of these results is useful for the interpretation of LFT values and the management of liver diseases during pregnancy.

[Study of blood lead levels in a population of 616 subjects from the regions: Centre and Pays de Loire]. / Etude de la plombémie dans une population de 616 sujets des régions Centre et Pays de Loire.

OBJECTIVES: Low-lead level exposure has been associated with harmful health effects. Blood lead is the most widely used marker of exposure. In this work, our purpose was to evaluate the present level of blood lead in a group of 616 subjects from the general population living in two regions of France: Centre and Pays de Loire. METHODS: Subjects were randomly included in the study. Blood lead was measured by inductively coupled plasma mass spectrometry which is the most sensitive and specific method. RESULTS: The mean blood lead concentration of the population studied ranged from 46.7 +/- 20.5 micrograms/l in the 6-10 year old to 86.6 +/- 42.4 micrograms/l in the 50-66 year old subjects. From 385 children under 13 years old, 5 had blood lead higher than 100 micrograms/l, the maximum acceptable level recommended by the American Centers for Disease Control. Women had lower blood lead values than men and their levels remained unchanged until 50 years but increased beyond this age. CONCLUSION: Mean lead levels were low in this French population. There is however risk of higher levels in persons living in old housing.

[Prevalence of longitudinal melanonychia in the white population]. / Prévalence des mélanonychies longitudinales chez le sujet blanc.

OBJECTIVES: The aim of this study was to determine the prevalence of longitudinal melanonychia (ML) in white subjects in order to obtain epidemiological data suggesting management strategies. PATIENTS AND METHODS: We included 99 hospitalized patients in this study, all were examined by a dermatologist. Another 4,400 healthy subjects were examined by a general practitioner. Criteria retained were age, sex, the presence or not of ML, the localization, number of bands, intensity of the coloration and size. RESULTS: The prevalence of ML was 12.6 +/- 3.4 p. 100 (CI 5.9-19.3) and 1.4 +/- 0.18 p. 100 (CI 1.3-1.75) respectively in the 99 and 4,400 subjects. The percentage of subjects increased progressively with age, particularly after 45 years and reached a peak between 56 and 65 years. The age distribution was identical. The most frequent localization was the thumb, followed by the great toe and the index. None of the ML observed had a clinical presentation suggestive of melanoma and no biopsies were taken. CONCLUSION: The frequency of melanonychia is thus higher in this series than that reported by previous studies where less than 1 p. 100 of the subjects had melanonychia. It was highest between the ages of 45 and 65 years. These results should be used when counselling patients and proposing systematic exeresis of ML above the age of 45 years.

Serum alanine aminotransferase measurement as a guide to selective testing for hepatitis C during medical checkup.

The efficiency of elevated serum alanine aminotransferase values for selecting subjects to be tested for hepatitis B or C infections in a large French population undergoing a medical checkup was investigated. For 5 consecutive weeks, serum alanine aminotransferase values were controlled in 9044 subjects; 308 subjects (202 males) were selected with alanine aminotransferase levels 1.2-fold above the normal value (58 iu/l for men, 34 iu/l for women). For each selected case, an age- and sex-cross-matched control was included. Of the 308 subjects with elevated alanine aminotransferase values, one was HBsAg positive and 15 (seven males) were anti-HCV positive. All anti-HCV sera tested by enzyme immunoassay were also positive by three immunoblots and 11/15 (73%) were HCV-RNA positive by reverse transcription-polymerase chain reaction. Of the 308 control subjects, two were HBsAg positive and four (two males) were weakly anti-HCV positive by enzyme immunoassay. Only one weakly anti-HCV positive serum was reactive by one immunoblot and all were HCV-RNA negative. This study shows the usefulness of alanine aminotransferase screening to detect hepatitis C virus infection in the general French population. Many of the anti-HCV positive subjects detected in this study were not aware of their hepatitis C virus seropositivity (12/15) or that they were viremic (11/15). Use of this low-cost assay will considerably reduce the number of subjects to be tested for hepatitis C virus serological status and therefore the cost. It may make possible the investigation of large populations by setting up public health programs to detect and treat hepatitis C virus. Hepatitis C virus infected subjects detected in these programs could benefit from medical follow up, including antiviral therapy.

High-performance liquid chromatography with electrochemical detection for the simultaneous determination of the methoxylated amines, normetanephrine, metanephrine and 3-methoxytyramine, in urine.

A simple method for the simultaneous analysis of normetanephrine, metanephrine and 3-methoxytyramine (both free and conjugated) in human urine by reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection has been developed. Existing methods have been optimized for extraction by study of analytical parameters. The hydrolysed urines are purified and concentrated by successive passages on two ion-exchange resins and ammoniacal elution to eliminate interference from pigments or related chemical compounds. The methoxyamines are separated by high-performance liquid chromatography on a reversed-phase column. Detection and quantitation are achieved with an electrochemical detector using a vitreous carbon electrode. Samples can be injected at 25-min intervals. Reference values of adults and children are given.