Biomedical subjects

D Roche

Publications and source records attributed to D Roche.

At least 37 records · Page 2Linked to original sources

PubMed1998

The Fas counterattack in vivo: apoptotic depletion of tumor-infiltrating lymphocytes associated with Fas ligand expression by human esophageal carcinoma.

Various cancer cell lines express Fas ligand (FasL) and can kill lymphoid cells by Fas-mediated apoptosis in vitro. FasL expression has been demonstrated in several human malignancies in vivo. We sought to determine whether human esophageal carcinomas express FasL, and whether FasL expression is associated with increased apoptosis of tumor-infiltrating lymphocytes (TIL) in vivo, thereby contributing to the immune privilege of the tumor. Using in situ hybridization and immunohistochemistry, respectively, FasL mRNA and protein were colocalized to neoplastic esophageal epithelial cells in all esophageal carcinomas (squamous, n = 6; adenocarcinoma, n = 2). The Extent of FasL expression was variable, with both FasL-positive and FasL-negative neoplastic regions occurring within tumors. TIL were detected by immunohistochemical staining for the leukocyte common Ag, CD45. FasL expression was associated with a mean fourfold depletion of TIL when compared with FasL-negative areas within the same tumors (range 1.6- to 12-fold, n = 6,p < 0.05). Cell death of TIL was detected by dual staining of CD45 (immunohistochemistry) and DNA strand breaks (TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling). There was a mean twofold increase in detectable cell death among TIL in FasL-positive areas compared with FasL-negative areas (range 1.6- to 2.4-fold, n = 6, p < 0.05). In conclusion, we demonstrate a statistically significant, quantitative reduction of TIL concomitant with significantly increased TIL apoptosis within FasL-expressing areas of esophageal tumors. Our findings suggest Fas-mediated apoptotic depletion of TIL in response to FasL expression by esophageal cancers, and provide the first direct, quantitative evidence to support the Fas counterattack as a mechanism of immune privilege in vivo in human cancer.

Adenocarcinoma↗

PubMed1998

Tight clustering and hemizygosity of apomixis-linked molecular markers in Pennisetum squamulatum implies genetic control of apospory by a divergent locus that may have no allelic form in sexual genotypes.

Apomixis is a naturally occurring mode of reproduction that results in embryo formation without the involvement of meiosis or fertilization of the egg. Seed-derived progeny of an apomictic plant are genetically identical to the maternal parent. We are studying a form of apomixis called apospory that occurs in the genus Pennisetum, a taxon in the grass family. A cultivated member of this genus, pearl millet (Pennisetum glaucum), reproduces sexually. A wild relative of pearl millet, Pennisetum squamulatum, that is an obligate aposporous species, is cross-compatible with pearl millet when used as a pollen donor in the interspecific cross. We present herein the genetic mapping of 13 molecular markers in an interspecific hybrid population of 397 individuals that segregates for apomixis and sexuality. Surprisingly, 12 of the 13 markers strictly cosegregated with aposporous embryo sac development, clearly defining a contiguous apospory-specific genomic region in which no genetic recombination was detected. Lack of or suppression of recombination may be coincidentally associated with the chromosomal context of the apomixis locus or it may be a consequence of its evolution that is essential for preservation of gene function as has been previously shown in studies of complex loci in both plant and animal species.

Aneuploidy↗

PubMed1998

Fas ligand expression in primary colon adenocarcinomas: evidence that the Fas counterattack is a prevalent mechanism of immune evasion in human colon cancer.

Fas ligand (FasL) kills sensitive Fas receptor (FasR)-bearing cells by inducing apoptosis. FasL expressed by non-lymphoid cells within the eye and the testis mediates immune privilege by inducing apoptosis of Fas-sensitive infiltrating pro-inflammatory immune effector cells. It has previously been demonstrated by the present authors that the colon cancer cell SW620 expresses FasL and can kill lymphoid cells by Fas-mediated apoptosis in vitro. This 'Fas counterattack' was subsequently confirmed by others as a potential mechanism of immune privilege in various malignancies. The aim of the present study was to ascertain the prevalence of FasL expression in human colon cancer and to confirm that neoplastic colonic epithelial cells express FasL in vivo. The study of FasL expression by colon cancer cell lines was extended: it was shown that seven of eight colon adenocarcinoma cell lines expressed FasL mRNA, using reverse transcription-polymerase chain reaction (RT-PCR). Prevalent expression of FasL was confirmed in vivo: all the resected colonic tumours examined (31/31) were found to express FasL. In the tumours, FasL were co-localized to neoplastic colonic epithelial cells, using immunohistochemistry and in situ hybridization, respectively. FasL expression was independent of Dukes' stage, suggesting that it may occur throughout colon cancer progression. These results suggest that FasL is a common mediation of immune privilege in colon cancer.

Adenocarcinoma↗

PubMed1997

Post-prandial metabolism of triglyceride-rich lipoproteins in non-insulin-dependent diabetic patients before and after bezafibrate treatment.

Retarded post-prandial (pp) lipid clearance is potentially a major component of the increased cardiovascular risk incurred by hypertriglyceridaemic non-insulin-dependent diabetic mellitus (NIDDM) patients. The effect of bezafibrate (Bz, 400 mg per day for 5 weeks on chylomicron (CM) and remnant clearance after loads of 100 g of fat and vitamin A was therefore explored in 10 male patients (glycaemia 11.9 +/- 3.3 TG 4.5 +/- 2.4 mmol L(-1)). In all subjects CM-TG and retinyl palmitate (RP) were reduced by 50%, but 8-h non-CM (remnant) RP decreased only in initially mildly hypertriglyceridaemic subjects (-35%, P < 0.05), while in three patients with very elevated initial TG (epsilon3/3, epsilon3/2 and epsilon2/2 genotypes) 8-h remnant RP increased by 100%. The decrease in pp CM-TG correlated with that of fasting Sf 20-400 (r = 0.686, P = 0.026), suggesting that improved lipolysis was a major determinant of hypolipidaemic effect. Apo CIII synthesis is known to be depressed by Bz: concentrations were lower under Bz (P < 0.05). A positive correlation (r = 0.880, P < 0.001) with fasting TG before treatment and its disappearance after treatment suggested an involvement of high concentrations with hypertriglyceridaemia. Post-prandial non-esterified fatty acids were decreased by 35 in correlation with a significant (-19%, P < 0.05) improvement in fasting glycaemia (r = 0.801, P < 0.005). These results suggest that Bz acts both on lipolysis and on removal of CM remnants, but that removal can become saturated when lipolysis is massively improved.

Aged↗

PubMed1997

Expression of galanin in hypothalamic magnocellular neurones of lactating rats: co-existence with vasopressin and oxytocin.

Lactation is a physiological condition known to upregulate the expression of the hypothalamic neurohormones, oxytocin and vasopressin, in the rat supraoptic and paraventricular nuclei. Other neuropeptides such as galanin are co-localized in the same magnocellular neurones and their expression has been demonstrated to be regulated by different experimental and physiological conditions. In the present study, we investigated the possible changes in galanin expression during lactation, using in situ hybridization and immunohistochemistry separately or in combination. Galanin messenger RNA concentrations decreased on day 3 of lactation in both the supraoptic and paraventricular nuclei and remained low on day 7 of lactation, but no differences were observed between control and 14-day lactating rats. In parallel, immunopositive cell bodies were almost undetectable on day 7 of lactation and immunoreactivity remained weak after 14 days of lactation, whereas galanin immunoreactive profiles in the supraoptic nucleus were more numerous than in the control group. Moreover, the subcellular distribution of immunostaining changed on day 14 of lactation. Galanin immunoreactivity was confined around the nucleus in the control females, but it became weaker and more homogenously distributed throughout the cytoplasm in the lactating rats. Electron microscopy using a pre-embedding technique confirmed that galanin immunoreactivity was no longer restricted to the Golgi complex, but was apparent throughout in the cytoplasm. Multiple labellings showed galanin and galanin messenger RNA to be co-localized with oxytocin messenger RNA in neurones of the dorsomedial part of the supraoptic nucleus during lactation. Some of those doubly labelled cells also expressed vasopressin messenger RNA in the same conditions as revealed by a triple-labelling procedure. As these co-localizations have not been observed in female control rats, lactation provided an example of a physiological condition inducing oxytocin and galanin co-synthesis in a subpopulation of magnocellular neurones. In conclusion, we have demonstrated plasticity of galanin expression during lactation in the hypothalamic magnocellular neurones. This plasticity could be caused by changes in galanin expression or in galanin processing in magnocellular neurones.

Animals↗

PubMed1997

Usefulness of markers in managing tobacco withdrawal.

To evaluate the usefulness of tobacco markers in dependent smokers being treated with transdermal nicotine patches, a study was conducted at the Tobacco Withdrawal Consultation Centre at the Hôpital Laennec, Paris, France. 125 patients were included in the study and, in a first time, carbon monoxide in exhaled air, carboxyhaemoglobin, urinary nicotine and cotinine, Fagerström index, were measured and correlated to the amount of nicotine inhaled per day. The most significant value was observed for cotinine. In a second time, 25 patients were followed clinically and biologically with urinary continine monitoring (group FC) and 73 were followed up only clinically (group FC). The success rate of therapy 12 weeks after the end of treatment was 72% in group FB and 28% in group FC. The nicotine patch dose was positively correlated (p < 0.01) with successful outcome. The lower the urinary cotinine level at 4 weeks, the more likely was successful outcome (p < 0.05). If psychological factors remain important, urinary cotinine monitoring in the course of nicotine patch treatment thus favours successful withdrawal.

Administration, Cutaneous↗

PubMed1995

Vasopressin and oxytocin gene expression in intact rats and under catecholamine deficiency during ontogenesis.

The development of the hypothalamic vasopressin (VP) and oxytocin (OT) systems has been studied in rats from the 16th embryonic day (E16) until the 11th postnatal day (P11). The VP and OT mRNA-producing neurons were identified on cryostat sections by in situ hybridization using oligonucleotide probes labeled by [35S], [3H] or digoxigenin. Moreover, VP and OT gene expressions were evaluated either at E21 or at P11 following chronic depletion of catecholamines (CA). For this purpose, pregnant rats were daily injected with alpha-methyl-m(p)-tyrosine from gestational day 13 to 20 while neonates were daily injected with alpha-methyl-m(p)-tyrosine and neurotoxin 6-hydroxydopamine from postnatal day 2 to 10. No VP mRNA- or OT mRNA-expressing cells were observed in the hypothalamus of intact fetuses at E16, while 2 days later rather numerous VP and OT neurons occupied the anterior hypothalamus. One major bilateral group of VP and OT neurons was located in the supraoptic nucleus (SON). Less numerous labeled cells were found in the developing paraventricular nucleus (PVN). Some VP and OT neurons were also spread along the ventrolateral surface of the hypothalamus from the level of the median eminence, caudally, to the level of the optic nerves, rostrally. From E18 until birth, the OT neurons were localized in the dorsal portion of the SON, while its ventral portion was occupied by the VP neurons. The VP mRNA- and OT mRNA-expressing cells seemed to increase both in size and in number over the perinatal period. Frequent relatively long neuronal processes contained VP and OT mRNAs in fetuses and in newborns. When performed during the second half of the fetal life, the chronic depletion of CA did not cause any change in the VP and OT mRNA concentrations in the SON and PVN of fetuses. By contrast, similar treatment of neonates resulted in a significant increase of both mRNA levels in the SON. These data suggest that at least in the SON VP and OT gene expression might be under the inhibitory control of CA during the neonatal period.

Animals↗

PubMed1995

Short-term effects of centrally administered galanin on the hyperosmotically stimulated expression of vasopressin in the rat hypothalamus. An in situ hybridization and immunohistochemistry study.

Galanin (GAL) is a 29-amino acid peptide that is present in the hypothalamic magnocellular neurons of the rat supraoptic nucleus (SON) and paraventricular nucleus (PVN). Since previous studies revealed a possible role of GAL in the hydro-osmotic regulation, we have investigated the effects of GAL on the vasopressin (AVP) mRNA content in the hypothalamic magnocellular neurons. We demonstrated by in situ hybridization (ISH) and immunohistochemistry that 100 pmol of GAL or GAL fragment (1-16) injected into the lateral ventricle of anesthetized dehydrated male rats induced a rapid (10 min time interval) decrease of AVP mRNA and AVP content in the magnocellular cell bodies of SON and PVN. These effects were quantified on an autoradiographic film and were also obvious at the cellular level by using ISH with a radiolabeled or digoxigenin-labeled oligonucleotide probe. Oxytocin mRNA content is not altered by the same injection either in dehydrated male or lactating female rats. Under the same conditions of lactation, AVP mRNA content is not modified and the i.c.v. injection of GAL has no effect. GAL antagonist (M15) injection suppressed the GAL-induced decrease of AVP mRNA in the dehydrated rats and increased AVP mRNA level in control rats. The efficacy of M15 in antagonizing GAL effects on AVP mRNA suggests the involvement of GAL receptors in the regulation of the vasopressinergic cell bodies. Moreover, endogenous GAL seems to depress the AVP mRNA content of SON and PVN in vivo. The possible origin of endogenous GAL and the mechanisms by which GAL can regulate the AVP mRNA content are also discussed.

Animals↗

PubMed1994

[Quantification of passive smoking in an survey of smoking coaches in the French high-speed trains (TGV Sud-Est)].

OBJECTIVES: Passive smoking has been demonstrated in many situations. We designed an experimental protocol to measure passive smoking in the coaches of the French high-speed train (TGV) and to attempt to identify interindividual variability in sensitivity. METHODS: Ten healthy non-smokers (5 males, 5 females) volunteered to avoid exposure to tobacco smoke for the duration of the study. On three separate occasion they were subjected to a 5-hour trip in the smoking coaches of the French TGV (south-east line). Twelve-hour urine samples were collected before each trip and over the following 72 hours. Urinary cotinine was measured in each fraction. RESULTS: Significant levels of urinary cotinine were found for a prolonged period in these passive smokers. Elimination of the tobacco by-product was similar to the level observed in subjects smoking 2 to 5 cigarettes per day. The kinetics of cotinine elimination was reproducible from one trip to another for any given individual, however significant interindividual variability was observed despite normal liver function in all. CONCLUSION: Measurement of urinary cotinine is potentially useful in non-smokers who are involuntarily exposed to tobacco smoke and who wish to know the extent of their exposure.

Adult↗

PubMed1994

Adenomyoma of the small intestine in children.

Two cases of adenomyoma of the small intestine occurring in two young children are described. One child presented with intussusception. In the other, the lesion was an incidental intraoperative finding. Underreporting is probably a major reason for the apparent rarity of this lesion in the small intestine. The condition should be considered a cause of small bowel intussusception.

Adenomyoma↗

PubMed1994

Monoamine influence on neuropeptide gene expression during ontogenesis.

The present study aimed to check the hypothesis concerning the monoamine regulation of the differentiation of their target neurons during ontogenesis. For this aim, neuropeptide gene expression has been evaluated by in situ hybridization in targets for monoamines, differentiating peptidergic neurons, after monoamine depletion in rats during prenatal or early postnatal periods. In the first series of experiments, the vasopressin (VP) and oxytocin (OT) mRNA concentrations were measured in the supraoptic nucleus (SON) of rat fetuses at the 21st embryonic day (E21) following daily (E13-E20) treatment with the inhibitor of the catecholamine (CA) synthesis, alpha-methyl-m(p)-tyrosine. Similar study was performed with rats at the 11th postnatal day (P11) after daily (P2-P10) treatment with alpha-methyl-m-tyrosine and the neurotoxin, 6-hydroxydopamine. In the second series of experiments, the effect of serotonin (5-HT) depletion by the inhibitor of the 5-HT synthesis, p-chlorophenylalanine, on the vasoactive intestinal polypeptide (VIP) mRNA level in the suprachiasmatic nucleus (SCN) has been studied in fetuses and in neonates as described above. No changes were detected in the VP and OT mRNA concentration in the SON following CA depletion in fetuses, while similar treatment of neonates significantly increased both mRNA levels. On the contrary, the 5-HT depletion caused an increased VIP mRNA concentration in the SCN in fetuses but not in neonates. Thus, our data suggest a monoamine inhibitory influence on peptide gene expression in the differentiating target neurons during certain periods of ontogenesis.

Animals↗

PubMed1994

[A model of phenotypic plasticity: the hypothalamo-posthypophyseal neurons].

In neurons, which are post-mitotic cells, a structural and biochemical plasticity occurs, namely for the mediators. The magnocellular hypothalamic neurons innervating the neural lobe are a favourable model for the study of the dynamic aspects of neuropeptides expression. In fact, they synthetize these peptides in large amounts, as a function of the physiological or experimental conditions. In addition to the major neuropeptides, oxytocin (OT) and vasopressin (VP) which are contained in control rats within different neuronal populations, immunocytochemistry and in situ hybridization used alone or in combination in the same preparations have revealed other neuropeptides and corresponding mRNAs respectively. These multiple labellings demonstrate that after osmotic stimulation or during lactation some neurons are able to synthetize OT and VP simultaneously, together with galanin and even tyrosine hydroxylase (but not catecholamines). Similarly, hypophysectomy or transection of the pituitary stalk differentially modify the contents in mRNA coding for VP, OT and galanin. These results have also been described in other neuronal types such as spinal ganglia sensory neurons, suggesting possible mechanisms at different levels of genetic expression: transcription, translation, post-translational events and possibly interneuronal exchanges of mRNA. The in vivo regulation of this neurochemical plasticity probably involves the innervation of these neurons and perhaps the colocalized peptides themselves. In fact, galanin selectively inhibits the expression of VP but not that of OT. Functional implications of the neuronal phenotypic plasticity in the adaptation of the nervous system to the changing physiological conditions are discussed, together with its possible implications in pathology and therapeutics.

Humans↗

PubMed1994

Urine collection for nicotine and cotinine measurement in studies on nicotine addicts.

One of the reasons for the paucity of tabagism exposure data on the consequences of smoking is the difficulty in obtaining urine samples and the fact that the optimal storage conditions remains undetermined. The authors therefore assessed the influence of storage on urinary nicotine and cotinine levels both at room temperature and after freezing. The variations observed were not statistically significant for up to 30 hours at room temperature or for up to 8 days at -25 degrees C. They then studied the excretion of cotinine and nicotine in overnight and 24-h urine specimens collected from 90 non-smokers exposed to tobacco smoke and 40 smokers. The correlation between overnight and 24-h excretion was excellent in the case of cotinine (r = 0.89) and poor for nicotine (r = 0.18), probably because of their respective half-lives. Lastly, the usefulness of referring the urinary cotinine to the urinary creatinine was questioned. The authors conclude that valuable studies should be based on overnight urines samples stored at room temperature for up to 30 hours and then frozen at -25 degrees C until quantification of cotinine expressed in microgram/fraction.

Adult↗

PubMed1993

Two classes of differentially regulated glutamine synthetase genes are expressed in the soybean nodule: a nodule-specific class and a constitutively expressed class.

We have characterized two sets of cDNA clones representing the glutamine synthetase (GS) mRNA in soybean nodules. Using the 3'-untranslated regions of a representative member of each set, as gene member(s) specific probes, we have shown that one set of the GS genes are expressed in a nodule-specific manner, while the other set is expressed in other tissues, besides the nodules. The nodule-specific GS genes are expressed in a developmentally regulated manner in the nodules, independent of the onset of nitrogen fixation. The other class of GS genes is expressed constitutively in all tissues tested, but its expression level is dramatically enhanced in nodules following onset of N2 fixation. The latter set of genes is also expressed in cotyledons of germinating seedlings in a developmentally regulated manner. Analysis of hybrid select translation products and genomic Southern blots suggests that multiple gene members in each class are expressed in the nodules.

Amino Acid Sequence↗

PubMed1993

Combination of non-radioactive and radioactive in situ hybridization with immunohistochemistry: a new method allowing the simultaneous detection of two mRNAs and one antigen in the same brain tissue section.

We describe here a simple method for combining non-radioactive and radioactive in situ hybridization and immunohistochemistry on the same brain tissue section. This approach was first developed on the well-characterized hypothalamo-neurohypophyseal system, facilitating the optimization of the triple-labeling procedure and the verification of labeling specificity. We report the simultaneous detection of vasopressin (VP) mRNA with a digoxigenin-labeled oligonucleotide, oxytocin (OT) mRNA with a 35S-labeled oligonucleotide, and OT peptide in the same 12-microns cryostat section. This was performed on floating sections as follows: first, the two probes were hybridized simultaneously; second, the peptide was detected with an immunoperoxidase-DAB procedure; third, the digoxigenin-labeled probe was detected with an alkaline phosphatase-NBT/BCIP technique; and finally, the 35S-labeled probe was detected by histological autoradiography. We also demonstrate that this approach is suitable for the simultaneous detection of tyrosine hydroxylase and two less abundant mRNAs, vasoactive intestinal peptide and vasopressin mRNAs, in the suprachiasmatic nucleus. The combination of the three techniques did not significantly diminish their specificity or sensitivity. In conclusion, this new method, permitting the simultaneous detection of three different products of gene expression in the same section, could be useful for further analysis of the phenotypic organization and its plasticity in endocrine or neural tissues.

Animals↗

PubMed1992

Structure of cis,cis-4,6-diphenyl-2-(2-propenyl)-1,3-dioxa-2-phosphorinane 2-oxide.

C18H19O3P, M(r) = 314.32, monoclinic, P2(1)/n, a = 5.726 (6), b = 14.234 (7), c = 20.08 (1) A, beta = 92.54 (7) degrees, V = 1635 (4) A3, Z = 4, Dx = 1.277 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 1.71 cm-1, F(000) = 664, T = 296 K, R = 0.042, 1813 unique observed reflections. The X-ray structure determination of the title compound shows that the dioxaphosphorinane ring has a chair conformation in which the phosphoryl O atom (P=O) is equatorial, which explains the absence of substantial NMR deshielding by its P=O group on H(4) and H(6), which are axial.

Crystallization↗

PubMed1991

Hormonal dependence of pinopode formation at the uterine luminal surface.

The uterine luminal epithelium during the period of receptivity for nidation displays characteristic protrusions of the apical surface named pinopodes. The effects of oestradiol and progesterone, singly or in combination, on the formation and regression of pinopodes were investigated using scanning electron microscopy. The appearance of pinopodes was found to be strictly progesterone dependent. When given together with progesterone, before the development of pinopodes, high doses of oestradiol (plasma level approximately 300 pmol/l) inhibited pinopode formation; on the contrary, low doses of oestradiol (nidatory doses) did not interfere with the process until the 4th day of treatment. When oestradiol was given as a single injection, after pinopode formation, both doses were equivalent in inducing their regression 48-72 h later. It appears that the hormonal conditioning for pinopode formation and for the development of uterine receptivity for egg implantation is the same. These observations support the hypothesis that pinopodes could be an extremely useful tool to estimate uterine receptivity. The experiments we describe here, together with observations made a few years ago, in stimulated cycles in the human, suggest that implantation failure as a result of a hormonal imbalance during the time intervening between ovulation and nidation, may be a general phenomenon.

Animals↗

PubMed1991

Concentrations of high-density lipoprotein subfraction HDL2 and lipoprotein A-I in a random population of healthy subjects.

High-density lipoproteins (HDL) are now currently subdivided according either to density and size-HDL2 and HDL3--or to surface apoprotein composition--lipoprotein A-I (LpA-I) without A-II, and LpA-I:A-II. In samples from blood bank donors (60 women, 47 men), we evaluated HDL subclasses, LpA-I particles, and other classic risk factors for atherosclerosis and compared them with each other. We found a good correlation between HDL2 and LpA-I (r = 0.74, P less than 0.001), the correlation being more marked in women (r = 0.74) than in men (r = 0.67). LpA-I was also strongly correlated with total apolipoprotein A-I (apoA-I) (r = 0.61), which suggests that LpA-I represents a significant portion of the variable pool of apoA-I. By contrast, LpA-I:A-II but not LpA-I was correlated with HDL3, confirming the preferential association of LpA-I with HDL2. The difference between the sexes was more marked for HDL2 (+66% in women) than for LpA-I (+25%). We conclude that in normolipemic subjects the size of the HDL2 pool depends on that of LpA-I. Considering the speed and low cost of the assay, determination of HDL2 cholesterol might be a useful tool for assessing cardiovascular risk.

Apolipoprotein A-I↗