Effects of electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin.

In 1998, the authors studied the effect of residential exposure to electric and magnetic fields from high-power lines on female urinary excretion of 6-sulfatoxymelatonin (6-OHMS) in the Quebec city, Canada, metropolitan area. A sample of 221 women living near a 735-kV line was compared with 195 women the same age living away from any power lines. Participants provided morning urine samples on 2 consecutive days and wore a magnetic dosimeter for 36 consecutive hours to measure personal magnetic exposure. The indoor electric field was assessed by spot measurements. After adjustment for other factors associated with low melatonin secretion, such as medication use or light exposure, nighttime concentration of 6-OHMS was similar in the two groups. When either 24-hour or sleep-time exposure to magnetic field or electric field measurements was used, no exposure-effect relation was evident. However, the trend of decreasing 6-OHMS concentration with age was more pronounced for women living near the lines, as was a lower 6-OHMS concentration in women with high body mass index. Chronic residential exposure to magnetic fields from high-power lines may accentuate the decrease in melatonin secretion observed in some vulnerable subgroups of the population.

Captopril suppression versus salt loading in confirming primary aldosteronism.

This prospective study was designed to compare the captopril suppression test with the salt-loading approach to confirm the diagnosis of primary aldosteronism. A total of 49 patients were referred with a presumed diagnosis of primary aldosteronism. The captopril test was performed in the morning with patients in the seated position after overnight fasting. Blood samples for plasma aldosterone were obtained before captopril administration (25 mg PO) and again 2 hours later. Patients were then subjected to a high salt diet (300 mmol sodium per day for 3 days). On the third day, urinary sodium (24 hours) was measured, and plasma aldosterone levels were measured at 8:00 AM (recumbent) and at noon (standing). Of the 49 patients, 44 had nonsuppressible aldosterone concentrations with all the clinical characteristics of primary aldosteronism: 22 patients had surgically confirmed unique adenoma, and 22 patients had presumed bilateral hyperplasia. There was a significant correlation between plasma aldosterone values of salt-loaded patients (mean of 8:00 AM and noon results) and the values 2 hours after captopril administration (r=0.8, P<0.01). Plasma aldosterone cumulative distribution curves in primary aldosteronism patients (adenoma and hyperplasia) were not significantly different between the 2 suppression tests. Our results showed that the captopril suppression test is as effective as sodium loading in confirming the diagnosis of primary aldosteronism.

HDL cholesterol and TaqIB cholesteryl ester transfer protein gene polymorphism in renal transplant recipients.

Decreased serum levels of high-density lipoprotein cholesterol (HDL-C) are a well-known risk factor for coronary heart disease (CHD) in the general population and have been suggested as one of the best predictor of CHD after renal transplantation. However, very heterogeneous HDL-C levels have been reported in renal transplant recipients. In this patient population, serum HDL-C levels are determined by complex interactions between hormonal, environmental (such as a high amount of abdominal adipose tissue), and genetic factors and drugs (particularly glucocorticoids). We, therefore, evaluated the effects of the cholesteryl ester transfer protein (CETP) gene TaqIB polymorphism as well as of abdominal obesity on HDL-C levels in 78 male renal transplant recipients who were receiving azathioprine and/or ciclosporin A in combination with prednisone as immunosuppression. The patients were classified into genotypic groups according to the presence or absence of the restriction site (B1 allele or B2 allele, respectively). The distribution of CETP genotypes was similar to that previously described in the general population. Overall, HDL-C levels were 19 and 26% higher in B1B2 and B2B2 patients as compared with B1B1 homozygotes (p < 0.05), even after control for other lipid measurements. Patients with abdominal obesity (waist girth >/=93 cm) showed reduced HDL-C levels as compared with lean (waist girth <93 cm) patients (1.20 +/- 0.28 vs. 1.42 +/- 0.41 mmol/l, respectively, p < 0.01). Moreover, the HDL-C levels were markedly affected by the CETP TaqIB polymorphism in lean patients (+28 and +41% in B1B2 and B2B2 as compared with B1B1 patients, p < 0.05), but no significant difference was observed among obese patients. Significantly lower total cholesterol:HDL-C ratios were obtained in lean B2B2 homozygotes, suggesting that these patients could be less susceptible to atherosclerosis than lean B1B1 homozygotes. In addition, patients with the B1B1 genotype had more documented CHD as compared with patients carrying at least one B2 allele, supporting the protective effect of the B2 allele against CHD. In conclusion, considerable variation in HDL-C levels appears to be explained by the CETP TaqIB gene polymorphism in male renal transplant recipients, but this potential protective gene effect appears strongly reduced by concomitant abdominal obesity.

Effect of terminal renal failure on the ratio of free to total prostate-specific antigen.

OBJECTIVES: To evaluate the effect of terminal renal failure on the ratio of free to total prostate-specific antigen (PSA). METHODS: We measured free and total PSA in a group of 48 men on chronic hemodialysis. Samples were taken before dialysis and compared with a control group of 101 men without known prostatic or renal disease. Measurements of total and free PSA were made simultaneously with an ES-300 analyzer from Boehringer Mannheim according to the manufacturer's instructions. RESULTS: Patients on hemodialysis have lower complexed PSA but higher free PSA than controls. Therefore, we observed a markedly higher calculated proportion of free PSA in the dialysis group (0.54 +/- 0.16 vs. 0.33 +/- 0.14, p < 0.00001). The calculated proportion of free PSA decreases progressively as the levels of total PSA increases from 0 to 4 microg/l in both groups. By multivariate analysis, total PSA (p < 0.00001) and dialysis (p < 0.00001) were independent predictors of the fraction of free PSA. Age had no significant effect after correction for total PSA (p = 0.23). CONCLUSION: Patients on hemodialysis have normal total PSA but a significantly higher proportion of free PSA. Caution is therefore recommended for the interpretation of free PSA in that population since cutoff established in patients without renal disease may be inappropriate.

Transcription factors interacting with herpes simplex virus alpha gene promoters in sensory neurons.

Interference with VP16-mediated activation of herpes virus immediate-early (or alpha) genes is thought to be the major cause of establishing viral latency in sensory neurons. This could be brought about by lack of a key activating transcription factor(s) or active repression. In this study we find that sensory neurons express all important components for VP16-mediated alpha gene induction, such as the POU transcription factor Oct-1, host cell factor (HCF) and GABP alpha/beta. However, Oct-1 and GABP alpha/beta are only present at low levels and the VP16-induced complex (VIC) appears different. We do not find protein expression of the transcription factor Oct-2, implicated by others as an alpha gene repressor. The POU factor N-Oct3 (Brn 2 or POU3F2) is also present in sensory neurons and binds viral TAATGARAT motifs with higher affinity than Oct-1, indicating that it may be a candidate repressor for competitive binding to TAATGARAT motifs. When transfected into HeLa cells, where Oct-1 and GABP alpha/beta are highly abundant, N-Oct3 represses model promoters with multimerized TAATGARAT motifs, but fails to repress complete alpha gene promoters. Taken together our findings suggest that modulation of alpha gene promoters could contribute to viral latency when low concentrations of the activating transcription factors Oct-1 and GABP alpha/beta prevail. Our data, however, refute the notion that competing Oct factors are able to block alpha gene transcription to achieve viral latency.

Positive and negative regulation at the herpes simplex virus ICP4 and ICP0 TAATGARAT motifs.

The control of the ICP0 and ICP4 immediate early genes of herpes simplex virus (HSV) can critically determine the course of viral lytic or latent infections. Their promoters contain so-called TAATGARAT motifs that are activated via a multiprotein complex which includes cellular proteins Oct-1 and HCF and the viral activator (VP16 (= Vmw65, alpha TIF). Relative to the ICP4 promoter TAATGAGAT sequence, the ICP0 promoter motif has a 5' extension that includes a full octamer sequence (ATGCTAATGATAT). It seemed possible that this overlapping octamer site might render the ICP0 promoter element more active by allowing tighter binding of the Oct-1/VP16 complex or more vulnerable to repression by other Oct proteins. Our experiments favor the former possibility. On the one hand, the extended ICP0 site shows stronger binding of the Oct-1/VP16 complex compared to the ICP4 site. Moreover, transcription of a reporter gene with multiple ICP0 sites is strongly activated by VP16 in transfected cells. On the other hand, the ICP0 site is largely refractory toward repression by a different Oct factor (N-Oct2 = Brn1) which competes with Oct-1/VP16 for the site. In marked contrast, multiple copies of the conventional TAATGAGAT motif of ICP4 are poorly activated by VP16, and transcription from this site can be completely repressed by N-Oct2. However, inclusion of the neighboring CGGAAR motifs from the ICP4 promoter, which bind factors GABP alpha and beta, results in a strong synergistic activation. This activity, like that of the complete ICP4 promoter, becomes refractory to repression by competing N-Oct2. Thus the standard TAATGARAT motif of ICP4 is by itself less active and more vulnerable to repression than the extended ICP0 motif, and its activation depends upon synergism with neighboring DNA sites and their cognate factors. This difference between the two types of TAATGARAT motifs may allow for a more complex transcriptional regulation by factor combinations.

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.

Laminin-binding protein 120 from brain is closely related to the dystrophin-associated glycoprotein, dystroglycan, and binds with high affinity to the major heparin binding domain of laminin.

When brain proteins separated by SDS-polyacrylamide gel electrophoresis (PAGE) and transferred to nitrocellulose are probe with 125I-labeled laminin, a single broad band of approximately 120 kDa binds laminin specifically. We show here by two-dimensional electrophoresis and protein microsequencing that this band consists of two distinct laminin-binding proteins. One of these is the amyloid precursor protein. The other, laminin-binding protein (LBP) 120, is closely related to the dystrophin-associated glycoprotein, dystroglycan (156 kDa); 5 peptides from purified bovine brain LBP120, ranging in size from 7 to 19 residues, are up to 100% identical to the predicted amino acid sequence of muscle dystroglycan (ibraghimov-Beskrovanaya, O., Ervasti, J. M., Leveille, C. J., Slaughter, C. A., Sernett, S. W., and Campbell, K. P. (1992) Nature 355, 696-702). These protein microsequence data support the data of Ibraghimov-Beskrovnaya et al., which suggest that the dystroglycan precursor is processed into 120/156- and 43-kDa proteins. Moreover, the data suggest a revision in the position of the proposed cleavage site of the precursor. The glycosylation and extracellular localization of LBP120/dystroglycan are consistent with it being a cell surface laminin receptor. LBP120/dystroglycan, either as a native protein, or following SDS-PAGE and transfer to nitrocellulose, binds with high affinity (Kd = 90 nM) to a proteolytic fragment of laminin (E3) containing the major heparin binding domain. This binding is Ca(2+)-dependent and inhibited by low concentrations of heparin. Thus, LBP120/dystroglycan is a major non-integrin laminin receptor whose high affinity interaction with laminin may reflect a structural role in brain and muscle.

Genetic mapping of the integrin alpha 1 gene (Vla1) to mouse chromosome 13.

The integrin alpha 1 chain (Vla1) associates with the beta 1 chain to form a heterodimer that functions as a dual laminin/collagen receptor in neural cells and hematopoietic cells. We have used an interspecies backcross gene-mapping technique to map the Vla1 gene to the distal end of chromosome 13 in the mouse genome. The Vla1 locus is located 3.5 cM distal to Ctla-3 and 7.8 cM distal to Htrla. We have further characterized this locus in recombinant inbred (RI) mice by examining the strain distribution patterns of nine genomic DNA restriction fragment length variants detected with alpha 1 cDNA probes. The RI gene mapping did not show linkage to previously mapped genes or mutants in the AXB, BXA, or AKXD RI sets and therefore defines a new genetic marker for the distal end of chromosome 13 in these RI sets.

Nonintegrin laminin receptors in the nervous system: evidence for lack of a relationship to P40.

Laminins are extracellular matrix proteins that mediate their effects on cells through integrin and nonintegrin receptors. Two receptors of 67 and 110 kD that bind laminin with a high affinity (Kd approximately nM) have been reported in neural cells. Here, we discuss these and other nonintegrin laminin receptors that have been implicated in neural function. In addition, we report studies characterizing a 43 kD protein, (P40), immunologically related to the 67 kD laminin receptor, which may be involved in retinal development. In our studies, polyclonal antisera (anti-P-20-A) to a synthetic peptide derived from the sequence of a cDNA for a putative high-affinity laminin receptor (67 kD) detected a protein of 43 kD in immunoblots of adult rat retinas. Immunohistochemistry with this antiserum showed that the retinal immunoreactivity was predominantly localized in the ganglion cell layer of both adult chicken and rat retinas where it appeared to be intracellular. Retinal ganglion cells were shown to be immunoreactive by retrogradely labeling them from the superior colliculus with a lipophilic dye and subsequently with anti-P-20-A antisera. Consistent with the preferential localization of the P-20-A immunoreactivity in ganglion cells, there was a substantial decrease in the amounts of P40 on Western blots following optic nerve section and resulting retinal ganglion cell death. Screening of a rat (PC12 cell) cDNA library with the anti-P-20-A antiserum further confirmed the specificity of the antiserum for the rat homologue of P40. Rat P40 is 97% identical to the mouse and 87% identical to human P40 at the nucleic acid level and 98% at the protein level. Restriction mapping of the rather abundant positive clones in the library that cross-hybridized with a human cDNA probe for P40 indicated that the full-length cDNA of 1.2 kb was the major and perhaps the only cDNA in the library. In Northern blots of adult rat retina, these clones hybridized to a single 1.2-kb transcript. Electroblots of retinal homogenates probed with radioiodinated laminin demonstrated binding to a broad band at 110 kD, but none at 43 kD. Taken together these findings suggest that P40 may not be a laminin receptor and are in keeping with the hydrophilic composition of the protein, its intracellular localization, as well as other features predicted by its nucleic acid sequence.(ABSTRACT TRUNCATED AT 400 WORDS)

Genetic linkage analysis in recombinant inbred mice of P40, a putative clone for the high-affinity laminin receptor.

Recombinant inbred (RI) mice were used to genetically map sequences of a 43-kDa protein, P40, that was originally identified as a high-affinity laminin receptor. More recent data have implicated this protein in development of the retina (Rabacchi et al. Development 109: 521-531, 1990), possibly via its proposed function in protein translation (G. Brawerman, personal communication). We have identified, in Southern blots, a set of P40-related sequences in BXD recombinant inbred mouse DNA. Ten restriction fragment length polymorphisms (RFLPs) segregate among the RI strains and display strain distribution patterns (SDPs) which are linked in varying degrees to previously typed loci on Chromosomes (Chrs) 1, 3, 6, 9, 11, 14, and 19. An intronic DNA probe from an incompletely processed P40 mRNA transcript overlaps with two of these loci mapping near the cholecystokinin gene locus on the distal arm of Chr 9 and to another site on the distal arm of Chr 6, suggesting that functional genes probably reside at least at these two sites. These P40 loci comprise part of a multimember gene family that is well dispersed in the mouse genome.

Visceral perception in health and functional dyspepsia. Crossover study of gastric distension with placebo and domperidone.

The symptoms of functional dyspepsia are still unexplained. To evaluate the possible role of abnormal visceral perception, we studied the symptomatic responses and the pressure variations during progressive gastric distension in 10 female healthy control subjects (mean age 33.6 years) and in 10 female patients with functional dyspepsia (mean age 35.2 years). A rubber balloon was positioned 4 cm below the lower esophageal sphincter (LES) and inflated with progressively larger volumes of air by steps of 50 ml; pressures at the gastric fundus and at the LES were continuously recorded by perfused manometric catheters. Each subject was studied on two separate occasions after randomized double-blind administration of either placebo or 20 mg of domperidone. Symptomatic responses and the manometric data were analyzed at the time of the initial recognition of distension (bloating step) and at the time of reporting pain or up to a maximum of 700 ml of balloon inflation (pain or 700-ml step). On placebo, the volumes of gastric distension were more than two times lower in patients than in control subjects at the bloating step (185 +/- 32 ml vs 470 +/- 40 ml, P = 0.001) and at the pain or 700-ml step (265 +/- 54 ml vs 600 +/- 34 ml, P less than 0.005), while the pressure gradients (pressure at inflation steps minus baseline pressure before beginning inflation) were not statistically different between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Determination of serum activity of placental alkaline phosphatase]. / Détermination de l'activité sérique de la phosphatase alcaline placentaire.

The authors have developed an enzymatic method for the measurement of serum placental alkaline phosphatase (PLAP) based on the hydrolysis of paranitrophenyl phosphate into para-nitrophenol. The specificity for the isoenzyme involved is achieved by means of its characteristics thermostability. After one hour incubation at 60 degrees C, PLAP still maintains its full activity, while other isoenzymes are completely inactivated. The sensitivity of the method was improved (less than 1 U/l) by optimizing parameters such as the volume of specimen, the nature of the buffer (2-methyl-amino-ethanol), the reaction time and the pH. Analysis of the method performances has revealed a lower detection limit of 0.12 U/l, a linearity from 0 to 50 U/l, a precision lower than 10% for most of the analytical range and a complete enzyme recovery. The reference range was estimated from 0 U/l to 0.33 U/l in a group of 125 non-smokers without any cancerous disease.

Isolation and partial characterization of high affinity laminin receptors in neural cells.

Neural cells in culture (NG-108, PC12, chick dorsal root ganglion, chick spinal cord, and rat astrocytes) bind laminin with an apparent Kd of congruent to 10(-9) M. Laminin affinity chromatography of chick brain membranes washed with 150 mM NaCl and eluted with 0.2 M glycine buffer, pH 3.5, yields a single protein with an apparent molecular mass of 67 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Isoelectric focusing and peptide mapping indicate that the 67-kDa protein is distinct from bovine serum albumin (68 kDa) but indistinguishable from high affinity laminin receptors isolated from skeletal muscle. After electroblotting onto nitrocellulose paper and probing with 125I-laminin, this putative laminin receptor binds laminin specifically (100 ng/ml). A second protein (congruent to 120-140 kDa) is also detected with 125I-laminin (100 ng/ml) in the laminin affinity-purified membrane proteins. Both 67- and congruent to 120-140-kDa proteins can be laminin affinity-purified from cultures enriched for neurons (greater than 90%) following metabolic labeling with [35S]methionine. Our data suggest that neural cells (dorsal root ganglion, central nervous system neurons, astrocytes, and several neural cell lines) have high affinity binding sites for laminin and that two membrane proteins, 67- and congruent to 120-140-kDa, are responsible at least in part for this binding.

Adult celiac sprue: changes in the pattern of clinical recognition.

We report the clinical, laboratory, and pathological findings in a series of 52 consecutive patients with adult celiac sprue observed over a 20-year period. The frequency of that diagnosis increased from an average of 0.7 case/year during the period 1966-1975 to 5.8 cases/year during the period 1981-1985. Apart from two patients with dermatitis herpetiformis, nonclassical clinical presentations were observed in 16 of 50 (32%) patients overall and in 13 of 28 (46%) patients diagnosed since 1981. Diarrhea was the most common complaint leading to the diagnosis; since 1981, hematologic abnormalities warranted investigation in 38% of the patients. Decreased iron stores (88%), decreased red cell folate (82%), or both (74%), and abnormal radiographic studies of the small bowel (83%) were the most sensitive tests in the diagnostic investigation. We conclude that atypical or nonclassical presentations of adult celiac sprue, mostly with hematologic abnormalities, are not uncommon.