[Mother-infant Interactions with Very Low Birth Weight multiple newborns (< 1500 g). A comparison of mother-multiple and mother-single births]. / Mutter-Kind-Interaktion bei sehr leichtgewichtig frühgeborenen Mehrlingen (< 1500 g). Ein Vergleich von Mutter-Mehrlings- und Mutter-Einlings-Dyaden.

BACKGROUND: Assisted reproductive techniques and fertility enhancing therapies have increased the rate of multiple births and, therefore, the risk of prematurity. Our hypothesis is that mothers of preterm multiples are less able to provide such enhancing interactions than mothers of preterm singletons, resulting in a developmental disadvantage for preterm twins and triplets. PATIENTS AND METHODS: Of 77 very low birth weight preterms (VLBW) who were examined prospectively with their mothers in a longitudinal study, 35 were multiples and 42 were singletons. At a corrected age of three months the quality of the mother-infant interaction with multiples vs. singletons was examined. The Mannheim Rating System, a 40-item standardized observation instrument based on a 10 minute videotaped sequence of interaction, was used. RESULTS: The analyses showed several differences between mother-singleton and mother-multiple interactions. Mothers of multiples were less stimulating and reactive and showed less babytalk. Multiple infants were also less reactive than singletons. In mother-multiple dyads there were less verbal exchanges between mother and child. CONCLUSIONS: There are definite differences in mother-multiple compared to mother-singleton interactions, so that VLBW multiples may be at even greater risk for negative mother-infant interactions than singletons.

How could aortic arginase activity enhancement be involved in DOCA-salt hypertension?

This study was to examine whether the increase in aortic arginase activity observed in DOCA-salt hypertensive rats is involved in the mechanism of physiological hypertension by participating to vessel hypertrophy and/or to the impairment of endothelium-dependent relaxation to acethylcholine. We measured polyamine content and relaxation-response to acethylcholine in aortic rings isolated from control and DOCA-salt treated Sprague-Dawley rats after in vitro modification of arginase activity. Polyamine content was significantly increased in aorta from DOCA-salt hypertensive rats compared with controls. In the normotensive rats, the addition of L-valine (an inhibitor of arginase) decreased the relaxation response to acethylcholine whereas the addition of arginase increased the relaxation dependent response. On the contrary, in DOCA-salt hypertensive rats, the addition of L-valine or of arginase did not change the endothelium dependent relaxation. The results obtained suggest that the increase in aortic arginase activity in DOCA-salt hypertension could contribute to vascular hypertrophy but not to the impairment of endothelium-dependent relaxation.

[Specificity hypothesis of a theory of mind deficit in early childhood autism]. / Zur Spezifitätshypothese eines Theory-of-Mind Defizits beim Frühkindlichen Autismus.

OBJECTIVES: In order to test the hypothesis that a theory of mind deficit is specific for autism, the present study presents the first replication of the Sally-Anne test (Baron-Cohen, Leslie & Frith, 1985) in the German-speaking countries. METHODS: The Sally-Anne test was administered to 16 autistic, 24 probands with Down's syndrome and 20 normal preschool prosands. The intelligence of the autistic group and that with Down's syndrome was measured by the CPM/SPM. In addition, the ADI-R was used with the principal caregivers of the autistic and Down's syndrome subjects. RESULTS: With regard to the clinical diagnosis, theory of mind deficit turned out to be not specific for autism. Six of 16 (37.5%) autistic subjects passed the theory of mind tasks. Thus performance in the autistic group surpassed that of both control groups. Out of 16 autistic subjects, autism could be confirmed in only 8 on the basis of the ADI-R diagnostic criteria, only one of whom showed a theory of mind. The autistic individuals with a theory of mind differed significantly in their mean IQ from those without this ability. CONCLUSIONS: Spectrum and specificity of a theory of mind deficit in autism remain controversial. For further research it seems important to administer the ADI-R during the diagnostic process. The findings suggest that the clinical diagnosis of autism is not precise enough to distinguish between autism and nonautistic mental handicap.

Resveratrol inhibits intestinal tumorigenesis and modulates host-defense-related gene expression in an animal model of human familial adenomatous polyposis.

We studied the effect of oral administration of resveratrol, a natural constituent of grapes, on tumorigenesis in Min mice. Min mice are congenic mice genetically predisposed to develop intestinal tumors as a result of a mutation of the Apc gene. Resveratrol (0.01% in the drinking water containing 0.4% ethanol) was administered for seven weeks to Min mice starting at five weeks of age. The control group was fed the same diet and received water containing 0.4% ethanol. Resveratrol prevented the formation of colon tumors and reduced the formation of small intestinal tumors by 70%. Comparison of the expression of 588 genes in the small intestinal mucosa showed that resveratrol downregulated genes that are directly involved in cell cycle progression or cell proliferation (cyclins D1 and D2, DP-1 transcription factor, and Y-box binding protein). In addition, resveratrol upregulated several genes that are involved in the recruitment and activation of immune cells (cytotoxic T lymphocyte Ag-4, leukemia inhibitory factor receptor, and monocyte chemotactic protein 3) and in the inhibition of the carcinogenic process and tumor expansion (tumor susceptibility protein TSG101, transforming growth factor-beta, inhibin-beta A subunit, and desmocollin 2). Our data highlight the complexity of the events associated with intestinal tumorigenesis and the multiplicity of the molecular targets of resveratrol. The high potency and efficacy of resveratrol support its use as a chemopreventive agent in the management of intestinal carcinogenesis.

Nitric oxide synthase inhibition promotes carcinogen-induced preneoplastic changes in the colon of rats.

l-Arginine is metabolized either to polyamines through arginase and ornithine decarboxylase (ODC) activities or to citrulline and nitric oxide (NO, nitrogen monoxide) through the NO synthase (NOS) pathway. Polyamine levels and ODC activity are high in tumor cells. The aim of this study was to test whether N(G)-nitro-l-arginine methyl ester (l-NAME), an inhibitor of NOS, modulates colon carcinogenesis. Adult male Wistar rats were treated with azoxymethane (AOM, 15 mg/kg ip), a chemical carcinogen, once a week for 2 weeks. One week after the second injection the rats were randomly divided into two groups. One group (n = 8) received l-NAME (10 mg/kg body wt/day) in drinking water. The control group (n = 8) received tap water. After 5 weeks, the rats receiving l-NAME showed enhanced mean basal arterial blood pressure, decreased heart rate, and a significant decrease of the cGMP content in the colonic mucosa. In both groups, AOM induced the formation of colonic aberrant crypt foci (ACF). In l-NAME-treated rats, the number of ACF was higher than in controls by 47%. ODC activity was enhanced by 11-fold. S-Adenosyl-methionine-decarboxylase activity and putrescine concentration were significantly increased in the colonic mucosa of l-NAME-treated rats. The data suggest that l-NAME promotes carcinogen-induced preneoplastic changes in the colon by inhibiting NOS activity and by stimulating polyamine biosynthesis.

Blood polyamine levels after oral ornithine load, a diagnostic marker of hyperproliferative premalignant and malignant stages in a model of colon carcinogenesis.

This study was performed to determine whether a single oral dose of ornithine (Orn), the substrate of ornithine decarboxylase (ODC), increases blood concentrations of polyamines premalignant stage, and whether blood polyamine levels could be used as predictive markers of cancer development. Male Wistar rats were divided into two groups, control and 1,2-dimethylhydrazine (DMH)-treated rats. DMH (20 mg/kg body weight) was injected intraperitoneally once weekly for 10 weeks. Five, 7, and 10 weeks after the last injection when premalignant aberrant crypt foci have developed in the colon, blood levels of putrescine (PUT), spermidine (SPD), and spermine (SPM) were estimated before and after an oral load of ORN. The results showed that after a single oral load of Orn, blood PUT, but not SPD and SPM, concentrations were significantly higher in DMH-treated rats compared with control rats, indicating enhancement of ODC activity. These results support the view that the increased blood concentration of PUT after administration of Orn may be a useful marker to detect hyperproliferative premalignant and malignant stages of cancer development.

Suppression of azoxymethane-induced preneoplastic lesions and inhibition of cyclooxygenase-2 activity in the colonic mucosa of rats drinking a crude green tea extract.

We determined the effects of a crude green tea extract given as drinking fluid on the promotion/progression phase of colon carcinogenesis in rats after induction of the neoplastic process by azoxymethane. Adult Wistar rats were given azoxymethane (15 mg/kg i.p.) once a week for two weeks. One week after the second injection, the rats were randomly divided into two groups. One group (n = 8) received daily prepared aqueous solutions of green tea extracts (GTE; 0.02%, wt/vol); the control group (n = 8) received tap water. After six weeks, rats receiving GTE showed a 60% reduction in the number of colonic preneoplastic lesions (aberrant crypts). The number of individual crypts per aberrant crypt focus (crypt multiplicity) was significantly reduced in the GTE group; the majority (80%) of the remaining aberrant foci contained only one or two preneoplastic crypts. A significant and selective decrease of cyclooxygenase (COX)-2 activity was observed in the colon of rats receiving GTE (23 +/- 3 vs. 117 +/- 30 mU/mg protein in controls), whereas COX-1 showed no alterations. Our data demonstrate that GTE reduces COX-2 and suppresses the formation of colonic preneoplastic lesions. They provide new insights into the mechanism of chemopreventive and anti-inflammatory properties of green tea.

Promotion of intestinal carcinogenesis by dietary methionine.

The metabolism of the polyamines spermidine and spermine is known to be enhanced in rapidly proliferating cells. Methionine is a precursor of the aminopropyl moieties of these amines. Therefore, it was of interest to study the effects of a methionine supplemented diet on polyamine metabolism and preneoplastic changes occurring in the intestinal tract of rats treated with the chemical carcinogen azoxymethane (AOM). Adult Wistar rats received 15 mg AOM/kg body wt (i.p.) once each week for 2 weeks. Thereafter, the rats were randomly divided into two groups and received controlled isoenergetic diets containing the same amount of folate, choline and vitamin B12 during 12 weeks: one group was kept on a standard diet; the other was fed the same diet, except that 1% L-methionine was added at the expense of carbohydrates. After 12 weeks, the administration of the methionine-supplemented diet stimulated the turnover rate of ileal epithelial cells, indicating enhanced crypt cell proliferation. Furthermore, in this group, a 2-fold increase in the number of aberrant hyperproliferative crypts and the appearance of tumors was observed in the colon. These effects were accompanied by the increased formation of spermidine and spermine due to the enhancement of S-adenosylmethionine decarboxylase activity and by the upregulation of Cdx-1, a homeobox gene with oncogenic potentials. The experimental data do not support the view of a chemopreventive effect of dietary methionine supplementation on intestinal carcinogenesis in rats, even at an early phase of preneoplastic development, but rather suggest that methionine promotes intestinal carcinogenesis.

Concomitant changes in polyamine pools and DNA methylation during growth inhibition of human colonic cancer cells.

The effects of CGP 48664 and DFMO, selective inhibitors of the key enzymes of polyamine biosynthesis, namely, of S-adenosylmethionine decarboxylase (AdoMetDC) and ornithine decarboxylase (ODC), were investigated on growth, polyamine metabolism, and DNA methylation in the Caco-2 cell line. Both inhibitors caused growth inhibition and affected similarly the initial expression of the differentiation marker sucrase. In the presence of the AdoMetDC inhibitor, ODC activity and the intracellular pool of putrescine were enhanced, whereas the spermidine and spermine pools were decreased. In the presence of the ODC inhibitor, the AdoMetDC activity was enhanced and the intracellular pools of putrescine and spermidine were decreased. With both compounds, the degree of global DNA methylation was increased. Spermine and spermidine (but not putrescine) selectively inhibited cytosine-DNA methyltransferase activity. Our observations suggest that spermidine (and to a lesser extent spermine) controls DNA methylation and may represent a crucial step in the regulation of Caco-2 cell growth and differentiation.

Preventive administration of ornithine alpha-ketoglutarate improves intestinal mucosal repair after transient ischemia in rats.

OBJECTIVES: To investigate whether the preventive enteral administration of a polyamine precursor, such as ornithine alpha-ketoglutaiate (OKG), has a beneficial effect on the repair process of the intestinal mucosa after transient mesenteric vascular occlusion. DESIGN: A controlled laboratory study. SETTING: A research laboratory facility at the Research Institute for Digestive Cancer. SUBJECTS: Male Wistar rats, weighing 330 to 350 g, housed individually in plastic cages under standardized conditions (23 degrees C, 73 degrees F, 60% relative humidity, 12-hr light and 12-hr dark cycles). INTERVENTIONS: Intragastrically, 1.5 or 17 hrs before surgery, animals received either distilled water (water group), or an amino acid solution of either OKG (1 g/kg) or L-lysine (0.68 g/kg) in distilled water under isonitrogenous conditions. Intestinal ischemia was produced in anesthetized rats by occluding the superior mesenteric artery for 90 mins with a microbulldog clamp. At the end of the ischemic period, the clamp was removed, allowing reperfusion, and the abdomen was closed. MEASUREMENTS AND MAIN RESULTS: At 0, 4, and 24 hrs after ischemia/reperfusion, the midjejuno-ileum was resected. Intestinal morphology, polyamine content, and hydrolase activities were determined. In all groups at the end of the ischemic period, the villi were dismantled with preservation of the crypts. Rats treated with OKG exhibited a restoration of short villi by 4 hrs after ischemia/reperfusion. In other groups, the villi remained extensively denuded. By 24 hrs, only rats treated with OKG showed a complete recovery of normal mucosal architecture. The amount of the polyamines, putrescine, and spermidine were significantly enhanced by 4 hrs after ischemia/reperfusion in the mucosa of rats treated with OKG, as compared with the two other groups. At a functional level, sucrase and aminopeptidase activities remained significantly higher by 4 hrs of ischemia/reperfusion in rats treated with OKG as compared with rats receiving water or lysine. By 24 hrs, hydrolase activities were normalized in rats treated with OKG, whereas an important deficit in hydrolase activities remained in rats receiving either water or lysine. CONCLUSIONS: OKG administration to rats did not prevent ischemic damage of the intestinal mucosa, but it accelerated the repair of the mucosa during reperfusion. OKG favored the restitution of normal villus architecture and the functional recovery of the intestinal mucosa. We hypothesized that OKG-triggered metabolites might mediate the restitution process and contribute to the healing of the intestinal mucosa by minimizing cell injury and by promoting the replacement of injured cells.

Suppression of preneoplastic changes in the intestine of rats fed low levels of polyamines.

Administration for 7 days of an enteral diet that is naturally deficient in polyamines strikingly reduces the preneoplastic changes observed in the intestines of adult Wistar rats previously treated with the carcinogen 1,2-dimethylhydrazine. On the contrary, supplementing the enteral diet with spermidine favors preneoplastic development. The effects of the low-polyamine diet included a 40% decline in the putrescine content of the intestinal mucosa, a significant decrease in the turnover rate of the epithelial cells from the crypts to villus tip in the ileum, and a 2-fold reduction in the number of abnormal colonic crypts. The experimental data support the view that it might be of interest to control the dietary intake of polyamines in the clinical management of cancer patients.

[Adoption: psychiatric risk and/or protective factor?]. / Adoption: psychiatrisches Risiko und/oder protektiver Faktor?

Epidemiologic studies reveal that adoptees are overrepresented in referrals to child psychiatric facilities as well as show more often psychiatric disturbances compared with their nonadopted peers. Therefore the adoptive status is indicating a psychiatric risk. To explain the underlying mechanisms it seems useful to comprehend the adoption as a process. The adoptees' situation must be described as bearing multiple risks. On the other hand the adoption itself can be seen as a protective factor too. It nevertheless can produce additional problems. In order to enhance the success in therapy these adoption-specific risk factors witch can deteriorate the relationship between the adoptive parents and their children must be considered.

Nitric oxide and the digestive system in mammals and non-mammalian vertebrates.

The focus of the presentation will review the distribution of nitric oxide (NO)-producing sites in the digestive system in mammals and nonmammalian vertebrates and will center on the roles that NO plays in modulating physiological and pathophysiological functions in digestive system.

Prophylactic administration of L-arginine improves the intestinal barrier function after mesenteric ischaemia.

BACKGROUND: Ischaemia/reperfusion (I/R) of the intestine causes mucosal injury associated with a high death rate in rats. AIM: To investigate whether nitric oxide (NO) might be implicated in the recovery of the intestinal mucosa after ischaemic insult. METHODS: Wistar rats were subjected to mesenteric artery occlusion for 90 minutes. The animals were given either L-arginine, the substrate of NO synthase, or molsidomine, a NO donor. The controls received casein hydrolysate. The compounds were administered by gavage 19, 16, and 1.5 hours before ischaemia. Mucosal barrier permeability and cGMP content were determined 24 hours after ischaemia. RESULTS: Survival after I/R was 50% in the control group. Animals treated with L-arginine or molsidomine exhibited a higher survival rate (70% and 83% respectively). Mucosal barrier permeability was decreased in rats receiving L-arginine or molsidomine compared with controls (4.0 (0.9) and 2.6 (0.6) v 11.2 (1.6) 14C-PEG pmol/segment, p < 0.05). Increased cGMP content was seen in the mucosa of the L-arginine group. CONCLUSION: The findings suggest that pretreatment with L-arginine or molsidomine ameliorates survival after intestinal I/R and improves mucosal barrier function.

Intestinal absorption of calcium in vivo is dependent on endogenous nitric oxide.

This study examines the role of nitric oxide (NO) in the regulation of calcium absorption in the small intestine. Calcium absorption was quantified by measuring 45Ca++ transport from lumen to blood in an intestinal segment (duodenum and 20 cm of the proximal jejunum) perfused by both intraluminal and vascular routes in anesthetized rats. When administered i.v. as bolus injections, NG-nitro-L-arginine methyl ester (L-NAME, 10 mg.kg-1), an inhibitor of NO biosynthesis, decreased calcium absorption with a concomitant increase in blood pressure and a decrease in mesenteric blood flow. Conversely, the nitrovasodilators 3-morpholinosydnonimine (2 mg.kg-1) and S-nitroso-N-acetylpenicillamine (10 micrograms.kg-1), which generate NO spontaneously, both increased calcium absorption with no change in mesenteric blood flow. When infused i.v., L-NAME (3 mg.hr-1.kg-1 for 40 min) induced a decrease in calcium absorption that was reversed by the NO donor sodium nitroprusside (1.5 mg.hr-1.kg-1 when infused for the last 20 min of the 40-min L-NAME infusion). Sodium nitroprusside infusion (1.5 mg.hr-1.kg-1) caused an increase in calcium absorption that was not reversed by L-NAME (3 and 30 mg.hr-1.kg-1). The present findings suggest that NO is involved in basal calcium absorption in rat small intestine in vivo.

Blood pressure effects of calcium intake in experimental models of hypertension.

Calcium intake has been implicated as being an important factor in the development and treatment of hypertension. The mechanisms underlying the relationship between calcium and blood pressure are not yet clearly defined. Experimental studies have documented an inverse association between calcium intake and blood pressure level. For 15 years it has been shown that calcium supplementation is effective in lowering blood pressure in hypertensive rats and, on the other hand, calcium deprivation results in increased blood pressure levels. Enriched calcium diets decrease blood pressure in genetic hypertension displayed by spontaneously hypertensive rats (SHR), stroke-prone SHR, Lyon hypertensive rats or Dahl salt-sensitive rats and, in volume-dependent hypertension induced by saline and mineralocorticoid or angiotensin II administration in Wistar or Sprague-Dawley rats. Efficacy is observed with calcium carbonate added in the diet and with calcium chloride or calcium gluconate in drinking water. Compared with the normal level in the diet (0.5% to 1%), calcium supplementation represents mainly a fourfold increase whose effect is more intense in young weaning animals treated for a long-lasting period (4 to 10 weeks).

Endogenous nitric oxide is not involved in acute parathyroid hormone-induced hypotension in rat: effect of hypertension and hypoparathyroid status.

The present study investigated the acute hypotensive effect of parathyroid hormone (PTH) in anesthetized adult spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats. Furthermore, in order to determine the possible contribution of nitric oxide (NO), a mediator of endothelium-dependent vasorelaxation, hypotensive responses to PTH were obtained in the presence of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis. The hypotensive effect of PTH (expressed as % of baseline blood pressure) was similar for the two strains. In the presence of L-NAME (18.5 mumol/kg), both strains demonstrated a similar hypotensive response to PTH, indicating that the hypotensive response to PTH is NO-independent.

Endothelium is a target organ of parathyroid secretions in genetic hypertensive rats.

We investigated the relationships between vascular endothelium and parathyroid function. Blood pressure (BP), circulating endothelins (ETs) and atrial natriuretic peptide (ANP), and BP responses to parathyroid hormone (PTH) and NG-nitro-L-arginine methyl ester (L-NAME) were measured in parathyroidectomized (PTx), PTx and fed a Ca2+ enriched diet (PTx-HCa) and sham SHR.22 weeks after surgery, BP was significantly decreased in PTx and PTx-HCa, plasma ETs levels were increased, whereas ANP levels were decreased. In anesthetized rats, BP increase induced by L-NAME was greater in PTx-HCa than in sham group, indicating increased endogenous nitric oxide release in hypoparathyroid rats. The hypotensive response to PTH remained unchanged. These data demonstrate that endothelium is activated in long-term hypoparathyroid SHR, reflecting an adaptative response to decreased BP.

Beneficial effects of L-arginine on intestinal epithelial restitution after ischemic damage in rats.

The polyamines are involved in repair processes after intestinal ischemia. Arginine and ornithine, both precursors of polyamines were therefore expected to exert beneficial effects on mucosal barrier dysfunction. Arginine may also generate NO and there is support for the view that NO may be beneficial after an ischemic insult. Male Wistar rats were given, by gavage, isonitrogenous solutions of L-arginine (0.5 g/kg) or L-ornithine (0.7 g/kg) 17 and 2 h before ischemia. Controls received an isonitrogenous solution of casein hydrolysate (1 g/kg). Transient intestinal ischemia was produced in anesthetized rats by occluding the superior mesenteric artery for 90 min. Intestinal morphology, hydrolase activities, polyamine and cGMP contents, and cell proliferation rates were determined 4 h after reperfusion. Administration of arginine or ornithine did not prevent ischemic damage but accelerated morphological repair, enhanced cell proliferation, and polyamine content was observed. Arginine was significantly more effective than ornithine. Formation of cGMP was enhanced after arginine administration. NG-nitroarginine methylester, an inhibitor of NO synthase, prevented the arginine effects on mucosal repair. We conclude that arginine-derived NO is an important mediator in the restitution of intestinal mucosa by minimizing cell injury during reperfusion.