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Biomedical subjects

J Levy

Publications and source records attributed to J Levy.

At least 127 records · Page 7Linked to original sources
PubMed1997

Effects of lycopene-enriched tomato oleoresin on 7,12-dimethyl-benz[a]anthracene-induced rat mammary tumors.

Consumption of carotenoids has frequently been inversely correlated with cancer incidence. In this report we used the 7,12-dimethyl-benz[a]anthracene (DMBA)-induced rat mammary tumor model to compare the effect of lycopene-enriched tomato oleoresin on the initiation and progression of these tumors with that of beta-carotene. Rats were injected i.p. with lycopene-enriched tomato oleoresin or beta-carotene (10 mg/kg, twice per week) for 2 weeks prior to tumor induction by DMBA and for an additional 16 weeks after carcinogen administration. HPLC analysis of carotenoids extracted from several tissues showed that both carotenoids were absorbed into blood, liver, mammary gland, and mammary tumors. The tomato oleoresin-treated rats developed significantly fewer tumors, and the tumor area was smaller than that of the unsupplemented rats. Rats receiving beta-carotene showed no protection against the development of mammary cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1997

[The surgical management of obstructive sleep apnea syndromes. Preliminary phase I results (the Stanford technic) in a series of 26 patients].

Surgical management of obstructive sleep apnea remains a surgical challenge. Multidisciplinary collaboration is a fundamental element. We report the principles of management as proposed to the patient and preliminary results obtained in a series of 26 patients treated in the phase I of the Stanford protocol. Cure rate after this phase was 50%. Different research projects in this area are discussed.

Adult↗
PubMed1997

Parathyroid hormone and parathyroid hormone-related peptide in venous umbilical cord blood of healthy neonates.

Objective of this study was to assess the role umbilical cord serum parathyroid hormone (PTH), and parathyroid hormone-related peptide (PTH-RP) may play in maintaining the maternal-fetal calcium (Ca) gradient. PTH and PTH-RP and total and ionized Ca levels were measured in blood samples of 20 neonates immediately after birth. Maternal peripheral blood total Ca was measured simultaneously. Mothers were free of hypertension, diabetes or Ca disorders. Neonates were healthy term babies with Apgar scores of eight or greater at one and at five minutes post delivery. PTH was measured using an immunoradiometric double antibody assay that recognizes intact PTH (1-84). PTH-RP was measured by an immunoradiometric double antibody assay that recognizes only PTH-RP (1-74). There was no overlap between the two assays. Ca levels in the neonates were higher than those in their mothers (p < 0.01), confirming a maternal-fetal Ca gradient. However in 18 out of 20 neonates PTH levels in cord blood were below the detection limit (3 pg/ml) and PTH-RP levels also were below detection limit (0.2 pmol/L). PTH-RP and PTH levels in the other two neonates were 0.5 and 0.6 pmol/L (PTH-RP) and 3 pg/ml (PTH) which are in the low normal range for normal adults. We conclude that these data do not support a role for either PTH or PTH-RP in venous cord blood in maintaining the maternal-fetal Ca gradient. They are, however, compatible with a paracrine role for these hormones.

Calcium↗
PubMed1996

Mitogen-activated protein kinase in neutrophils and enucleate neutrophil cytoplasts: evidence for regulation of cell-cell adhesion.

We employed neutrophils and enucleate neutrophil cytoplasts to study the activation of the mitogen-activated protein kinases (MAPKs) p44erk1 and p42erk2 in neutrophils by inflammatory agonists that engage G protein-linked receptors. Formyl-methionyl-leucyl-phenylalanine (FMLP) rapidly and transiently activated MAPK in neutrophils and cytoplasts, consistent with a role in signaling for neutrophil functions. FMLP stimulated p2lras activation in neutrophils and Raf-1 translocation from cytosol to plasma membrane in cytoplasts, with kinetics consistent with events upstream of MAPK activation. Insulin, a protein tyrosine kinase receptor (PTKR) agonist, stimulated neutrophil MAPK activation, demonstrating an intact system of PTKR signaling in these post-mitotic cells. FMLP- and insulin-stimulated MAPK activation in cytoplasts were inhibited by Bt2cAMP, consistent with signaling through Raf-1 and suggesting a mechanism for cAMP inhibition of neutrophil function. However, Bt2cAMP had no effect on FMLP-stimulated MAPK activation in neutrophils. The extent of MAPK activation by various chemoattractants correlated with their capacity to stimulate neutrophil and cytoplast homotypic aggregation. Consistent with its effects on MAPK, Bt2cAMP inhibited FMLP-stimulated aggregation in cytoplasts but not neutrophils. Insulin had no independent effect but primed neutrophils for aggregation in response to FMLP. Our studies support a p2lras-, Raf-1-dependent pathway for MAPK activation in neutrophils and suggest that neutrophil adhesion may be regulated, in part, by MAPK.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1996

Detection of virus in vertically exposed HIV-antibody-negative children.

BACKGROUND: HIV-infected mothers can transmit their infection to their children in utero or at delivery (vertical transmission). There have been cases of children who were reported as acquiring infection vertically and later clearing the infection. We report the frequency of this phenomenon in a European cohort study. METHODS: In four centres of the European Collaborative Study of children born to HIV-infected mothers, 299 children became HIV-antibody-negative and 264 of these had been followed up with virus culture and PCR for viral DNA at least once. FINDINGS: Nine of the 264 children were positive by virus culture or PCR, and subsequently seroreverted. Two of the nine tested virus-positive after they became antibody-negative. Six cases were virus-positive early in life and became negative thereafter, which is consistent with clearance of infection. The pattern was less clear in the other three. The nine cases had had their last virus test at age 16-101 months. All nine children had been bottlefed only. Eight had been delivered vaginally. The children had no HIV-related symptoms and received no anti-HIV treatments. Based on only those children who had two or more positive virological tests, we estimate that 2.7% (6/219) cleared or "tolerated" the virus. INTERPRETATION: The detection of virus or viral DNA in "uninfected" children born to HIV-infected mothers was rare and was not associated with clinical disease or immunological abnormalities. The timing of samples will affect the documentation of clearance since, in uninfected children of HIV-positive mothers who cleared the virus, viraemia was intermittent. Current paediatric opinion is to inform parents of children who serorevert that the child is not HIV-infected.

Child, Preschool↗
PubMed1996

Prolactin concentrations in preterm and term pregnancy and labour.

Maternal plasma and amniotic fluid (AF) were obtained for measurement of prolactin concentrations from: 1) 20 patients with preterm labor and intact membranes who delivered within one week of amniocentesis; 2) 20 patients with preterm labor who responded to tocolysis and delivered at term; 3) 20 women at term who were not in labor and 4) from 20 women in active labor at term. No significant differences were found between: 1) maternal plasma prolactin concentrations in women with preterm labor who delivered prematurely and those who delivered at term (155 ng/ml vs 176.5 ng/ml); 2) patients at term who were not in labor (188 ng/ml) and those who were in labor (155 ng/ml); 3) AF prolactin concentrations in the two preterm labor groups (1987.5 vs 1282.5 ng/ml) and 4) AF prolactin concentration in the two term groups (562 ng/ml vs 701 ng/ml). Prolactin concentrations were generally significantly higher preterm than at term. We concluded that no significant changes in maternal plasma and amniotic fluid prolactin levels were found in preterm and term parturition.

Adult↗
PubMed1996

Maternal plasma and amniotic fluid 17 beta-estradiol, progesterone and cortisol concentrations in women with successfully and unsuccessfully treated preterm labor.

Maternal plasma and amniotic fluid (AF) were obtained for measurement of 17 beta-estradiol, progesterone and cortisol concentrations from 40 patients with preterm labor and intact membranes at 28-32 weeks of gestation: 20 delivered preterm and the remaining 20 patients responded to tocolytic treatment and delivered at term. Maternal plasma and AF concentrations of these hormones were measured with specific commercially available radioimmunoassay kits. Maternal plasma and AF 17 beta-estradiol concentrations were significantly higher in women who delivered preterm than in those who delivered at term, 8.0 ng/ml vs 3.5 ng/ml and 0.85 ng/ml vs. 0.6 ng/ml, respectively. No significant differences were found between groups in maternal plasma and AF progesterone concentrations. Maternal plasma cortisol concentrations were higher in the preterm delivery group than in the term group (235 ng/ml vs. 55 ng/ml, respectively). No significant differences were found in AF cortisol concentrations between groups.

Adolescent↗
PubMed1996

Contribution of the polymerase chain reaction to the diagnosis of tuberculous infections in children.

UNLABELLED: The purpose of the study was to evaluate the contribution of polymerase chain reaction (PCR) to the diagnosis of tuberculous infection in children. Two different PCR techniques were compared to the standard bacteriological methods for the detection of Mycobacterium tuberculosis in 157 specimens obtained from the respiratory system of 51 children. Patients were classified in three groups: 12 patients with active disease (57 specimens), 12 patients with silent tuberculous infection (23 specimens) and 27 patients without tuberculosis (77 specimens). One PCR method (PCR/Ag85) used amplification of a fragment of the genes coding for the mycobacterial antigen 85 followed by hybridization of a probe specific for M. tuberculosis on the Southern blot of amplified DNA. The other PCR technique was a nested PCR (NPCR) using double amplification of a fragment of the insertion element IS6110 only present in the M. tuberculosis genome. The sensitivities of the different techniques, compared to the clinical diagnosis, were 7.0% for acid fast staining, 22.8% for culture, 24.6% for PCR/Ag85 and 44.9% for NPCR in active disease, 4.3% for culture, 8.7% for PCR/Ag85 and 28.6% for NPCR in silent tuberculous infection. The specificities were 100% for culture, 94.8% for PCR/Ag85 and 87.9% for NPCR. Among the 12 children clinically considered as having active tuberculosis, 1 had smear positive samples, 4 had at least one positive culture, 7 at least one positive PCR/Ag85 and 9 at least one NPCR positive sample. Among the 12 children having silent tuberculous infection, none had positive smears, 1 had one positive culture, 2 had at least one positive PCR/Ag85 and 5 at least one NPCR positive sample. CONCLUSION: Our study suggests that both PCR techniques, and especially NPCR, are able to detect M. tuberculosis DNA in specimens containing few micro-organisms. PCR methods are more sensitive than culture and the results are available more quickly. Testing multiple samples from the same individual increased the sensitivity. In view of occasional false-positive results, cultures remain the gold standard to establish definitive diagnosis of primary tuberculous infection in children.

Adolescent↗
PubMed1996

Maternal plasma and amniotic fluid dehydroepiandrosterone-sulfate concentrations in preterm labor and delivery.

The purpose of this study was to determine whether preterm parturition is associated with changes in maternal plasma and amniotic fluid dehydroepian-drosterone-sulfate concentrations. A cross sectional study was constructed according to the gestational age at admission and response to tocolysis. Group 1 consisted of women admitted with preterm labor and intact membranes between 28 and 31 weeks and 6 days gestational age (n = 40). Group 2 included 40 patients with preterm labor between 32 and 36 weeks gestational age. Both groups were classified into two subgroups: preterm delivery within seven days of admission and term delivery. Commercially available immunoassay kits validated for amniotic fluid analysis of DHEA-S, were used to measure maternal plasma and amniotic fluid DHEA-S concentrations. Maternal plasma DHEA-S concentrations were significantly higher in women with preterm labor who delivered preterm than in those who delivered at term. (Group 1: median 800 ng/ml [range 100-1100] vs. median 200 ng/ml [70-800], P < 0.001; Group 2: median 850 ng/ml [300-1700] vs. median 300 ng/ml [90-1100], P < 0.001). In contrast, no significant differences were detected in amniotic fluid DHEA-S concentrations. Our data suggest that the rise in maternal plasma DHEA-S concentrations observed in patients with preterm labor may be related to the effects of stress during labor.

Adult↗
PubMed1996

Further evidence that the callosum is involved in sustaining attention.

This study is a follow-up to a previous study that found a correlation between callosal efficiency and sustained attention. Normal children were tested on a vigilance task in which the amount of time between target presentations (interstimulus interval; ISI) was varied. Efficiency of the anterior callosum was assessed by a task that required subjects to perform incongruent movements with the left and right hands simultaneously. Subjects who showed less interference between the two hands missed fewer signals on the vigilance task after the longer ISIs, suggesting callosal involvement in the ability to sustain attention over a long period of time in the absence of sensory input. Age differences in the sustained attention were also observed.

Age Factors↗
PubMed1996

Evaluation of the developmental neuroendocrine and reproductive toxicology of aluminium.

Two experiments evaluating functional endpoints pertaining to the developmental neuroendocrine effects of aluminum in the rat are reported. A total of 31 timed mated dams were fed by daily gastric gavage 0, 5, 25, 50, 250, 500 or 1000 mg/kg body weight/day aluminum as a solution of aluminum lactate in distilled water from days 5 to 15 of gestation. The 390 offspring were evaluated for morphological and physiological parameters of reproductive functioning, including birth weight, anogenital distance (AGD), timing of vaginal opening, regularly of oestrous cycles, duration of pseudopregnancy (PSP), number of superovulated oocytes, and gonadal weight. No consistent or reproducible findings suggestive of toxic effect were found in the parameters of birth weight, AGD, timing of vaginal opening, duration of PSP, number of superovulated oocytes, and adult gonadal weight. A temporary increase in the proportion of aberrant oestrous cycles was detected during the first four cycles after vaginal opening, in the 250 mg/body weight/day group, with none by the fifth consecutive oestrous cycle. These results suggest that, apart from a transient disturbance of oestrous cycle regularity, aluminum does not have a developmental reproductive toxic effect.

Administration, Oral↗
PubMed1996

Small cell undifferentiated carcinoma of the colon associated with hepatocellular carcinoma in an immunodeficient patient.

Small cell undifferentiated carcinoma (oat cell carcinoma) is a malignant epithelial neoplasm with neuroendocrine features. It can appear as a primary tumor in many organs besides the lung, including the colon. We report a case of primary small cell undifferentiated carcinoma of the left colon with omental metastases in a 23-year-old man with a history of X-linked hyper-IgM syndrome. The patient had a simultaneous primary hepatocellular carcinoma. A literature review of this rare colonic malignancy is presented together with a discussion of the possible relationship of this tumor with hepatic malignancy and immunodeficiency.

Adult↗
PubMed1996

Evaluation of a new Epstein-Barr virus Combi Test for rapid serologic diagnosis of infectious mononucleosis.

We evaluated the EBV Combi Test (Virion) in serum samples from 574 children with a clinical presentation suggestive of infectious mononucleosis (IM) and compared its performance with several other EBV serological tests. Out of 574 sera 66 gave an acute IM pattern, 406 gave a past infection pattern and 102 were found negative in the EBV Combi Test. Positive VCA IgM and VCA IgG IFA results, in the absence of EBNA antibodies, were found in 62 cases in which the EBV Combi Test gave an acute IM pattern. In addition, 4 to the 574 tested sera gave an acute positive result in the EBV Combi Test (two of them were VCA IgM positive and the other two VCA IgM negative but also EBNA negative). None of these four sera were CMV IgM or Toxoplasma gondii IgM positive. The heterophile antibody test was positive in only 28, and VCA IgM EIA positive in 44 of the 62 IM cases. These data confirm the necessity for an EBV serological diagnosis in children where the clinical diagnosis of EBV infectious mononucleosis must be confirmed or ruled our.

Antibodies, Viral↗