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Biomedical subjects

J C Forest

Publications and source records attributed to J C Forest.

At least 37 records · Page 2Linked to original sources
PubMed1995

Increased immunohistochemical expression of neutral metalloendopeptidase (enkephalinase; EC 3.4.24.11) in villi of the human placenta with pre-eclampsia.

The purpose of this study was to identify the presence of placental neutral metalloendopeptidase (NEP; enkephalinase; EC 3.4.24.11) in human normotensive and pre-eclamptic pregnancy. The localization of NEP in placentae from normotensive, chronic hypertensive and pre-eclamptic pregnancies was carried out on fresh frozen tissues by using a monoclonal primary antibody developed against human common acute lymphoblastic leukaemia antigen (CD10) together with the avidin-biotin-peroxidase method. In placentae from normotensive, chronic hypertensive and superimposed pre-eclamptic pregnancies, intense staining was found in the extravillous trophoblast, and also in fibroblasts of the chorionic plate and stem villi. Light to moderate staining was noted in the villous-associated trophoblast and in some cells from the villous core. In cases of pre-eclampsia, very intense staining was detected not only on the surface, but also in the cytoplasm of the villous-associated trophoblast. The increased expression of placental NEP in pre-eclampsia suggests that this enzyme may be involved in the regulation of the local concentration of circulating biologically active peptides at the fetomaternal interface, and thus could be implicated in the pathophysiological changes of this syndrome.

Adult↗
PubMed1994

Glucose tolerance test during pregnancy: the significance of one abnormal value.

To determine the perinatal impacts of one abnormal oral glucose tolerance test (GTT) value, we conducted a retrospective study of pregnancy outcome in our population. Pregnant women (4314) were screened for gestational diabetes (GDM) between 24 and 32 weeks with the 50-g glucose challenge test and 183 were directly tested with the 100-g GTT. The subjects who had a serum glucose value equal or greater than 7.8 mmol/L 1 h after a 50-g glucose challenge were scheduled for a 100-g GTT (904). Another 32 subjects, who were not screened, were found to have gestational diabetes identified by repeated fasting and postprandial serum glucose measurements. Retrospectively, the study population was divided in four groups: I, normal (4138); II, GDM (237); III, subjects with one abnormal GTT value treated like GDM (85); IV, subjects with one abnormal GTT value untreated (69). Patient characteristics of groups II, III, and IV were similar. The area under the glycemic curve was similar between groups III and IV and was statistically inferior to that of Group II. GTT periodicity was the greatest in group II. Group II showed a higher rate of delivery before 37 weeks, of chronic and pregnancy induced hypertension, and of cesarian section but groups III and IV were not statistically different from group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Electrophoretic method for separating small peptides in serum without extraction of macromolecules: application to the detection of preeclampsia.

We optimized the electrophoretic separation using sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) and silver staining to detect small peptides in serum, without extraction of major proteins and applied this method to the search for specific peptides that may be used as early markers of preeclampsia during pregnancy. Appropriate separation of peptides was possible by modifying several parameters: increasing total proportion of monomers (%T) from 3 to 5% in the stacking gel; decreasing total proportion of crosslinker (%C) from 2.7 to 1.5% in the separating gel; selecting alkaline stacking gel buffer (pH 8.8) and alkaline sample buffer (pH 8.0); adding glycerol to both gels; and processing with weak current (15 mA). Silver nitrate staining was improved by using glutaraldehyde as the fixing agent, by reducing cross-linker concentration and by eliminating oxidizing and reducing agents. Sensitivity of the improved silver nitrate staining was 50 ng. We compared the electrophoretic pattern of serum peptides in the range of 2-14 kDa of 20 preeclamptic women with and without proteinuria and of 25 women in their third trimester who later developed preeclampsia to that of 24 normal pregnant women at term. No differences were found in the electrophoretic patterns among the groups and there was no correlation between the intensity of the bands and the severity of preeclampsia. We conclude that there is no characteristic electrophoretic pattern associated with preeclampsia.

Biomarkers↗
PubMed1994

A new rapid immunoinhibition pancreatic amylase assay: diagnostic value for pancreatitis.

A new rapid immunoinhibition pancreatic amylase assay was compared to total amylase and lipase in an unbiased sample of 1005 emergency department patients with suspicion of pancreatitis, of which 55 had a final diagnosis of pancreatitis. Imprecision of the assays for both amylases (less than 2.5%) were better than for lipase (less than 6.1%). Correlation (R2) of pancreatic amylase with total amylase was 0.991 but only 0.789 with lipase. Using Receiver Operator Characteristics analysis, the best diagnostic cutoff point for all three enzymes was near the upper limit of the reference interval. With pancreatic amylase, sensitivity, specificity, and predictive values for positive and negative results are, respectively, 85.5, 92.5, 39.8, and 99.1%; we found similar values for lipase but poorer values (78.2, 92.0, 36.1, and 98.7%) for total amylase. Tests combination did not improve the diagnostic performance significantly. In the diagnosis of pancreatitis, pancreatic amylase (p = 0.037) and lipase (p = 0.049) had better diagnostic performance than total amylase. The correct diagnosis of pancreatitis could be achieved in 47 instead of 43 patients with either pancreatic amylase or lipase as opposed to total amylase among 1005 patients in this study. We conclude that pancreatic amylase and lipase are incrementally better diagnostic tools than total amylase for the diagnosis of pancreatitis.

Acute Disease↗
PubMed1993

A prospective study of several potential biologic markers for early prediction of the development of preeclampsia.

OBJECTIVE: The purpose of this study was to prospectively evaluate the predictive performance of several potential biologic markers of preeclampsia used alone or in combination. STUDY DESIGN: A prospective cohort of 1366 nulliparous women was followed up longitudinally on three occasions during pregnancy. The predictive performance of the tests, used either alone or in combination (stepwise multiple logistic regression), was assessed and compared with that of the mean arterial pressure. RESULTS: Preeclampsia occurred in 109 of the pregnant women. At a specificity of 80% the sensitivity and the positive and negative predictive values for mean arterial pressure (at a threshold of 87 mm Hg) were 46.6%, 23.5%, and 92.0%, respectively, and the corresponding values for a multiple logistic model at 15 to 24 weeks that included some biologic markers, as well as the mean arterial pressure, were 57.1%, 26.9%, and 93.7%, respectively. CONCLUSION: Preeclampsia can be predicted by a combination of simple biologic tests with a performance similar to second-trimester mean arterial pressure. However, this procedure is insufficient in terms of clinical usefulness.

Biomarkers↗
PubMed1992

Correlation between ovarian steroids and lipid fractions in relation to age in premenopausal women.

OBJECTIVE: We evaluated the effect of sex steroids on the lipid fractions (cholesterol, triglycerides, LDL-C, HLD-C and subfractions HDL2-C and HDL3-C) and on the apolipoproteins (A-1 and B) in relation to age in women. DESIGN: Twenty-eight normally cycling women belonging to three age groups (20-29, n = 11; 30-39, n = 10; 40-49, n = 7) had blood samples taken daily during one cycle. MEASUREMENTS: Serum lipid fractions, apolipoproteins (Apo) and ovarian steroids were measured daily during the menstrual cycle. Diet and exercise were also evaluated. RESULTS: Each age group had comparable profiles for daily serum concentrations of oestradiol, progesterone and testosterone. There were no significant variations of the lipid fractions or of the ApoA-I and ApoB during the menstrual cycle in each group. Using regression analysis, modifications of cholesterol, triglycerides, LDL-C and ApoB were partially but significantly correlated with age. These changes occurred in spite of similar serum concentrations of oestradiol, progesterone and testosterone in the three groups. Lipid fractions were also affected by the increase of body mass index with age, especially HDL-C and HDL2C. However, there were no differences in lipid and energy intake or in energy expenditure during physical leisure activities. CONCLUSIONS: These results indicate that physiological fluctuations of ovarian steroids have no effects on lipids and Apo in normally cycling women of increasing age. In this study, the age related changes in the lipid fractions were partially correlated with body mass index but not with energy intake or exercise.

Adult↗
PubMed1991

Cholesterol fractions and apolipoproteins during endometriosis treatment by a gonadotrophin releasing hormone (GnRH) agonist implant or by danazol.

OBJECTIVE: The evaluation of cholesterol fractions and apoproteins during ovarian suppression by a GnRH agonist implant vs danazol in the treatment of endometriosis. DESIGN: A randomized study in 33 patients comparing goserelin (3.6 mg/4 weeks s.c., n = 20) with danazol (2 x 400 mg/day p.o., n = 13) in patients with a laparoscopic diagnosis of endometriosis and treated for 6 months. MEASUREMENTS: Triglycerides, cholesterol (C), LDL-C, HDL-C subfractions and apoproteins A-1 and B were measured at admission, at months 2, 4 and 6 of treatment and at month 2 post-treatment. RESULTS: After 1 month of therapy, serum oestradiol levels were maintained in the menopausal range with goserelin and in the early follicular phase range with danazol. Goserelin induced a significant elevation in HDL-C (by 31.4%), in HDL2-C (24.6%) and in HDL3-C (45.7%) but no significant change in LDL-C or in ApoA-1 and ApoB. By contrast, danazol caused significant diminutions in HDL-C (23.9%), HDL2-C (56.6%) and ApoA-1 (35.6%). Moreover, danazol increased LDL-C (10.5%) and ApoB (29.0%, P less than 0.05). The lipoprotein changes during goserelin had a favourable effect on the atherogenic index (cholesterol/HDL-C) and ApoA-1/ApoB ratio whereas those of danazol had opposite effects. These changes reverted 2 months after danazol while HDL was still elevated after goserelin. CONCLUSIONS: In relation to cholesterol, goserelin is a safe medication. The significance of temporary adverse changes in cholesterol fractions due to danazol is still unknown.

Adult↗
PubMed1990

[Prenatal diagnosis of trisomy 21].

Trisomy 21 is the most frequent chromosome anomaly found in the living newborns. Prenatal diagnosis by amniocentesis was limited until recently to older pregnant women. Maternal blood biochemical markers (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin) and ultrasonographic signs (nuchal fold thickening, femur length to biparietal diameter ratio) can discriminate a group of higher-risk women even though they are not aged. Numerous factors need to be considered when establishing such a screening program including pre-analytical variables (gestational age, diabetes, smoking, race), analytical variables (choice of reagents, quality control) or post-analytical (result reporting, follow-up of abnormal results). Until now the study of these markers has been restricted to the second trimester but they could become useful earlier during pregnancy.

Chorionic Gonadotropin↗
PubMed1990

[A computerized method for optimization of radioimmunoassays].

The authors have developed a one step quantitative method for radioimmunoassay optimization. The method is rapid and necessitates only to perform a series of saturation curves with different titres of the antiserum. After calculating the saturation point at several antiserum titres using the Scatchard plot, the authors have produced a table that predicts the main characteristics of the standard curve (Bo/T, Bo and T) that will prevail for any combination of antiserum titre and percentage of sites saturation. The authors have developed a microcomputer program able to interpolate all the data needed to produce such a table from the results of the saturation curves. This computer program permits also to predict the sensitivity of the assay at any experimental conditions if the antibody does not discriminate between the labeled and the non labeled antigen. The authors have tested the accuracy of this optimization table with two in house RIA systems: 17-beta-estradiol, and hLH. The results obtained experimentally, including sensitivity determinations, were concordant with those predicted from the optimization table. This method accelerates and improves greatly the process of optimization of radioimmunoassays.

Humans↗
PubMed1989

Double blind study on the efficacy and safety of tetrabamate and chlordiazepoxide in the treatment of the acute alcohol withdrawal syndrome.

1. Efficacy and safety of tetrabamate and chlordiazepoxide in the treatment of the acute or Primary Alcohol Withdrawal Syndrome (PAWS) were assessed during a randomized double blind clinical trial, carried out on sixty male alcoholic in-patients. 2. The two drugs were administered four times a day in double dummy conditions, according to a fixed-flexible decreasing dosage schedule (six days basic regimen). 3. Drug efficacy was measured daily throughout the study period using a battery of standard instruments for collecting quantitative clinical, behavioral, psychopathological and laboratory data. Side effects were daily recorded. 4. Tetrabamate was found to be as efficient as chlordiazepoxide in reducing the intensity of the PAWS, improving sleep and vital signs rapidly and alleviating anxiety progressively. 5. Tetrabamate was found particularly beneficial for severe tremor. Psychomotor and mood scores consistently favored tetrabamate, suggesting psychoanaleptic properties of this compound (increased diurnal vigilance). 6. Side effects were minimal with tetrabamate and generally of weak intensity with chlordiazepoxide. 7. The results of this study indicate that tetrabamate may represent a new alternative drug of choice for the therapy of the acute alcohol withdrawal syndrome.

Adult↗
PubMed1989

Determination of free testosterone fraction of human serum by gel bead dialysis.

The gel bead dialysis technique is an application of the steady-state gel filtration method. Preswollen gel beads are used as microdialysers. The gel is incubated for 3.5 h at 22 degrees C with 2.5 mL of serum and 3H-testosterone. During incubation, the equilibrium between free and protein-bound fractions is reached and the concentration of testosterone in the bead dialysate is equal to the free testosterone concentration in the incubation medium surrounding the beads. After incubation, the gel is separated from the medium by using a rigid filter and the radioactivity within the gel is counted. The effect on the assay of serum dilution and incubation time were studied. Within-batch imprecision (CV) was 3% (N = 30) and between-batch imprecision computed from lyophilized quality controls run over a one year-period, was 7%, 13% and 17% for free testosterone fractions (free over total) of 0.043, 0.032 and 0.021 respectively. An excellent correlation between this technique and the equilibrium dialysis method was found (r = 0.944, N = 59). Reference intervals were determined for men, women and pregnant women; mean +/- SD were 0.0216 +/- 0.0067 (N = 20), 0.0106 +/- 0.0020 (N = 20) and 0.0077 +/- 0.0017 (N = 19) respectively. Patients suffering from polycystic ovary syndrome had significantly higher free testosterone ratio (mean of 0.0285 +/- 0.0074, N = 20) than normal females.

Adolescent↗
PubMed1989

[Preeclampsia: physiopathology and prospects for early detection].

Preeclampsia is a complication of pregnancy characterized by hypertension, edema and proteinuria, beginning after 20 weeks of gestation. Six percent of the pregnant women in North America develop this disease, which is associated with increased morbidity and mortality for the mother and her baby. The physiopathology remains uncertain despite many research efforts. Actual hypotheses seek to explain the vasospasm that characterizes the disease. Among the many factors influencing vascular reactivity and possibly implicated are: the renin-angiotensin system, prostaglandins, progesterone and its metabolites, calcium, magnesium, digoxin-like immunoreactive substance(s), auricular natriuretic factor, substances secreted by platelets and leukotrienes. Prevention of the disease is limited by the absence of a biological or clinical marker with good sensitivity and appropriate specificity. Many biochemical or hematological parameters have been reported: uric acid, calcium, magnesium, proteinuria, blood iron, hematocrit, platelet count, antithrombin III, estrogen and progesterone. The combination of several tests could be superior to the use of each test individually, providing a better sensitivity and improving the positive predictive value. With early detection, new therapies for the prevention of the disease could be experimented on the higher risk women before the apparition of clinical symptoms or signs. Furthermore, those tests could be used in the study of the pathophysiology and in the choice of the best therapy.

Female↗
PubMed1989

[Determination of free thyroxine by adsorption on Sephadex gel].

The authors describe a simplified method for the measurement of free thyroxine based on the affinity of Sephadex gel for thyroxine. Radiolabeled thyroxine added to diluted serum is adsorbed by the gel proportionally to the free thyroxine concentration of the sample. The concentration of binding proteins present in the sample does not affect the adsorption of free thyroxine on the gel. The adsorbed thyroxine is separated by centrifugation and filtration using a rigid filter. Calibration is made against the equilibrium dialysis method. The intra (CV of 4.9 p. cent, 6.1 p. cent, 10.2 p. cent for concentrations of free thyroxine of 14.1, 27.1 and 67.6 pmol/l respectively) and interassay (CV of 5.3 p. cent, 8.2 p. cent, 9.2 p. cent at 9.4, 23.0 and 83.1 pmol/l respectively) imprecisions are comparable to equilibrium dialysis. The results obtained with this method show a good correlation with those of a two-step radioimmunoassay for patients without non-thyroidal diseases or pregnancy (r2 = 0.85, n = 50). The reference range (mean +/- two standard deviations) determined in 108 euthyroid adults is 10.3 to 21.9 pmol/l. Results obtained for hypothyroid patients (7.7 +/- 2.3 pmol/l, mean +/- one standard deviation, n = 26), hyperthyroid patients (47.4 +/- 22.9 pmol/l, n = 32), patients with non-thyroidal illnesses (18.7 +/- 4.9 pmol/l, n = 35) and pregnant women (10.8 +/- 1.7 pmol/l, n = 20) are in good agreement with those reported using equilibrium dialysis or ultrafiltration. Our method offers an alternative to more tedious techniques of free thyroxine determination in the hospitalized population for which the use of analog methods has been criticized.

Chromatography, Gel↗
PubMed1988

Fate of polyester arterial prostheses implanted as thoraco-abdominal by-passes in dogs: haematology, pathology, and biochemistry.

This study was designed to evaluate the haematological, pathological and biochemical characteristics of the flow surface in polyester arterial prostheses. Their implantations as thoraco-abdominal by-passes in dogs were scheduled to remain in place for periods ranging from four hours to six months. The haematologic parameters of the hosts were evaluated before implanting the prostheses and before harvesting the graft. To quantify the thrombogenicity of the flow surface, the platelet deposition and fibrinogen uptake were measured by means of an isotopic technique involving Indium-III labelled platelets and iodine-125 labelled fibrinogen. Synthesis of prostacyclin (PGI2) and thromboxane (TXA2) by the internal capsulae was determined by radioimmunoassay. The pathology was assessed according to previously described protocols. The haematologic parameters of the hosts did not alter substantially in the presence of the prostheses. The observed changes, though slight, were not pathologically significant 48 hours after implantation. Platelet and fibrin deposition was highest on the luminal surface of the prostheses 24 hours post-implantation. These decreased and became negligible after one month when the flow surface became smooth and glistening. The PGI2/TXA2 ratio of the luminal surface was much lower than that observed in native aortic tissue. These results show that the large calibre Dacron vascular prosthesis has a flow surface with a low degree of blood compatibility. The concentration of PGI2 on the newly-formed luminal surface remained low. This characteristic and the incomplete endothelialization of the luminal surface might be among the main factors that determine the high failure rate of synthetic prostheses when used as small diameter blood conduits.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Blood hemolysis by PTFE and polyurethane vascular prostheses in an in vitro circuit.

In order to improve understanding of the appearance of bright yellow stains in vivo (consecutive to the absorption of bilirubin) on a novel microporous, hydrophilic polyetherurethaneurea vascular prosthesis, the in vitro hemolytic activity of the material was compared with expanded polytetrafluoroethylene and silicone rubber. The results show that the tendency of the polyetherurethaneurea to produce free hemoglobin is low, so that the yellow staining observed is likely to be a result of the contact between the polymer and thrombi: Bilirubin is produced because of hemoglobin degradation in the thrombi rather than an active hemolysis on the surface of the prosthesis itself.

Biocompatible Materials↗