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Biomedical subjects

W Rascher

Publications and source records attributed to W Rascher.

At least 109 records · Page 6Linked to original sources
PubMed1997

Suppression of neuropeptide Y1 receptor function in SK-N-MC cells by nitric oxide.

The neuropeptide Y1 receptor (NPY1) predominantly mediates the vasoconstrictor effects of NPY in smooth muscle cells. The present experiments were planned to study the direct influence of the vasodilator nitric oxide (NO) on NPY1-receptor function. SK-N-MC and CHP-234 cells expressing Y1 and Y2 receptor, respectively, were incubated with the NO donors sodium nitroprusside (SNP), 3-morpholinosydnonimine (SIN-1), and S-nitroso-N-acetyl-penicillamine (SNAP). Receptor binding, Y1-receptor mRNA expression by Northern blot, and adenosine 3',5'-cyclic monophosphate (cAMP) and intracellular Ca2+ concentration ([Ca2+]i) responses were studied. SNP, SIN-1, and SNAP decreased normal binding of NPY to the NPY1 receptor in SK-N-MC cells in a concentration-dependent manner. SNP (500 microM), SIN-1 (1,000 microM), and SNAP (500 microM) significantly decreased binding to approximately 50%. The cell viability was not reduced. None of the NO donors affected Y2 receptor binding. Pretreatment with SNP significantly attenuated NPY-induced inhibition of cAMP formation in SK-N-MC cells but had no effect on CHP cells. The NPY-induced [Ca2+]i response was reduced to 50% by SNP pretreatment. NPY1 mRNA expression was reduced to one-third after SNAP treatment of SK-N-MC cells. In vitro, NPY1 receptor function of SK-N-MC cells is inhibited by NO-donor incubation on an mRNA level.

Blotting, Northern↗
PubMed1997

Urinary excretion of endogenous ouabain-like substance is reduced in NaCl supplemented premature infants.

Ouabain or an isomer has been identified as endogenous ouabain-like substance (EOLS). The role of EOLS in the adaptation of premature infants to alterations of sodium balance was investigated by measuring urinary ouabain excretion serially in 9 low birth weight premature infants with (group S, mean birth weight 1,578 g, mean gestational age 30.4 weeks) and without (group NS, mean birth weight 1,537 g, mean gestational age 30.8 weeks) NaCl supplementation. The study was performed on the 7th day and weekly thereafter until the 5th week of life. NaCl supplementation was given in a dose of 3-5 and 1.5-2.5 mmol/kg/day at the postnatal ages of 8-21 and 22-35 days, respectively. Prior to NaCl supplementation, urinary ouabain excretion was similar in the two groups (146.2 +/- 16.8 pg/kg/h in group S versus 180.0 +/- 9.6 pg/kg/h in group NS) and remained at about the same level throughout the study when supplemental NaCl was provided. In infants of group NS, urinary ouabain excretion increased significantly by the 3rd week (p < 0.01) and no consistent change occurred later on. As a result, the differences in urinary ouabain excretion between the two groups proved to be significant during weeks 2-5 (p < 0.001). Essentially the same pattern of ouabain excretion was seen when it was expressed in terms of pg/mg creatinine. In infants receiving high sodium diet there was a significant positive correlation between urinary sodium and ouabain excretion. It is concluded that premature infants receiving low sodium intake have elevated EOLS excretion by the 3rd week of life. Although the relationship between ouabain and sodium excretion in supplemented premature infants suggests some physiological significance for sodium excretion, ouabain does not appear to be regulated by extracellular volume.

Cohort Studies↗
PubMed1997

Urinary excretion of endogenous ouabain-like substance in furosemide-treated neonates: its relation to renal excretory pattern and endocrine factors.

The present study was undertaken to define the possible role of endogenous ouabain-like substance (EOLS) in controlling renal excretory pattern, in mediating the renal responses to furosemide and in inducing endocrine reactions in furosemide-treated neonates. Ten newborn infants with mean birthweight of 2,752 g and mean gestational age of 37.1 weeks were given furosemide in a dose of 1 mg/kg. Prior to and following furosemide therapy, urine was collected for a period of 12 h and analyzed for creatinine, osmolality, sodium and potassium, as well as for EOLS, arginine vasopressin (AVP), aldosterone and endothelin-1 (ET-1). In response to furosemide administration, urine flow rate and urinary osmolar, sodium and potassium excretion increased significantly, whereas creatinine excretion remained unchanged. Furthermore, following furosemide therapy, urinary excretion of EOLS (148.7 +/- 70.8 vs. 200.1 +/- 98.1 pg/kg/h) and AVP (19.5 +/- 5.4 vs. 27.8 +/- 7.8 pg/kg/h) tended to increase, whereas ET-1 (36.0 +/- 5.6 vs. 61.4 +/- 8.7 fmol/kg/h, p < 0.01) and aldosterone (507 +/- 120 vs. 751 +/- 203 ng/kg/h, p < 0.05) increased significantly. Prior to furosemide, urinary EOLS excretion was found to correlate positively with diuresis (r = 0.80, p < 0.01), sodium (r = 0.91, p < 0.001), creatinine (r = 0.75, p < 0.001), osmolar (r = 0.96, p < 0.001), ET-1 (r = 0.90, p < 0.001) and AVP (r = 0.92, p < 0.001) excretion. After furosemide, urinary EOLS excretion significantly correlated only with diuresis (r = 0.69, p < 0.05), ET-1 (r = 0.77, p < 0.01) and AVP (r = 0.92, p < 0.001). Urinary EOLS proved to be independent of aldosterone excretion irrespective of furosemide administration. It is concluded that urinary EOLS excretion is closely related to neonatal renal excretory pattern and it may have a role in controlling diuresis and natriuresis. The renal response to furosemide appears to be independent of EOLS, although interdependent endocrine reactions can be induced by furosemide which may modulate the production rate and urinary excretion of EOLS.

Aldosterone↗
PubMed1997

Levels of leptin in maternal serum, amniotic fluid, and arterial and venous cord blood: relation to neonatal and placental weight.

The mechanisms by which maternal and fetal weight are regulated during pregnancy are poorly understood. The ob protein, termed leptin, is produced by adipocytes. It is involved in the regulation of body weight by suppressing appetite and stimulating energy expenditure both in humans and rodents. In this study we examined whether leptin concentrations in the mother and the newborn correlate with birth weight, placental weight, and maternal weight at term. Leptin concentrations were measured in amniotic fluid, venous and arterial cord blood, and maternal serum at birth (n = 27) using a specific RIA employing human recombinant leptin for tracer and standard preparation. Gestational age was 38-42 weeks, maternal age was 21-42 yr, mean maternal weight at birth was 80.0 +/- 10.8 kg, and mean body mass index before pregnancy was 23.4 +/- 2.8 kg/m2. The newborns' mean weight was 3450 +/- 580 g, and mean placental weight was 616 +/- 120 g. Serum leptin levels from nonpregnant women ranged between 1.7-18.4 ng/mL, median 5.5 ng/ml (n = 30). Mean leptin concentration in maternal serum at birth was 20.0 +/- 13.2 ng/mL and was higher (P < 0.002) than in arterial cord blood (9.7 +/- 9.4 ng/mL) and venous cord blood (8.9 +/- 8.6 ng/mL). Mean amniotic fluid leptin concentration was 3.6 +/- 2.8 ng/mL. Placental weight correlated inversely with leptin levels in maternal serum at birth (r = -0.49, P < 0.01). In addition, leptin concentrations in venous cord blood correlated significantly with the levels in arterial cord blood (r = 0.98, P < 0.0001), and leptin levels in cord blood correlated positively with birth weight (r = 0.57, P = 0.03) and placental weight (r = 0.50, P < 0.01). In contrast, there was no correlation between maternal serum leptin levels and birth weight. Thus, leptin levels are high in the fetus and in the mother at term. We hypothesize that high leptin levels could represent an important feed-back modulator of substrate supply and subsequently for adipose tissue status during late gestation.

Amniotic Fluid↗
PubMed1997

Testosterone substitution normalizes elevated serum leptin levels in hypogonadal men.

The ob gene product leptin (OB) is a feedback signal from the adipocyte to the hypothalamus and is involved in regulation of food intake and energy expenditure in rodents. A major determinant of serum OB levels is fat mass. Several studies suggest that men have lower OB levels than women even after adjustment for percent body fat. We, therefore, investigated the influence of testosterone (T) substitution in hypogonadal men on serum OB levels. Hypogonadal men with T levels of 3.6 nmol/L or less and off substitution therapy for at least 3 months were assigned to two treatment groups: testosterone enanthate (TE; 250 mg, i.m., every 21 days; n = 10) or a single s.c. implantation of 1200 mg crystalline T (TPEL; n = 12). Blood samples for determination of T, 5 alpha-dihydrotestosterone (DHT), sex hormone-binding globulin, and 17 beta-estradiol were obtained before therapy and then every 21 days until day 189 and at follow-up visits on days 246 and 300. Serum OB levels were assessed on days 0, 42, 84, 126, 168, and 300. OB levels were referred to a normal range for men based on the analysis of OB levels in 393 adult men. Substitution with T led to a large rise in T and DHT in both groups compared to baseline values (average T, days 21-189: TE, 14.33 +/- 2.63 nmol/L; TPEL, 24.98 +/- 1.64; average DHT, days 21-189: TE, 4.20 +/- 0.57 nmol/L; TPEL, 5.11 +/- 0.56; P < or = 0.05). Concomitantly, 17 beta-estradiol increased in both groups, and sex hormone-binding globulin levels were significantly decreased. At baseline, serum OB levels in hypogonadal men were 3-fold elevated compared to those in normal men (12.39 +/- 2.93 micrograms/L vs. 4.28 +/- 0.52; P < 0.01) and not different between groups (TE, 13.7 +/- 5.6; TPEL, 11.3 +/- 2.9 micrograms/L). This elevation was retained after adjustment for body mass index in the normal control group [TE, 1.45 +/- 0.51 SD score (P < 0.0001); TPEL, 0.98 +/- 0.35 SD score (P < 0.0008)]. During T substitution serum OB was completely normalized (trough levels: TE, 4.6 +/- 1.0 micrograms/L; TPEL 4.3 +/- 0.9 micrograms/L). In multiple regression analysis, the androgen (T plus DHT)/estrogen ratio was the only significant determinant of OB levels (r = -0.32; P < 0.01). At baseline, OB levels did not correlate with body mass index, but during substitution, the correlation was considerably improved. We conclude that hypogonadal men exhibit elevated OB levels that are normalized by substitution with T. The only determinant of OB levels was the androgen/estrogen ratio, indicating a major influence of sex steroids on OB production. The interaction of T and OB might be part of a hypothalamic-pituitary-gonadal-adipose tissue axis that is involved in body weight maintenance and reproductive function.

Adult↗
PubMed1997

Plasma leptin levels in healthy children and adolescents: dependence on body mass index, body fat mass, gender, pubertal stage, and testosterone.

Leptin, the product of the ob gene, is thought to play a key role in the regulation of body fat mass. Beyond this function, it appears to be an integral component of various hypothalamo-pituitary-endocrine feedback loops. Because childhood and puberty are periods of major metabolic and endocrine changes, leptin levels and various hormonal parameters were investigated in a large cohort of healthy children and adolescents (312 males, 401 females, age 5.8-19.9 yr). For this purpose, a specific and sensitive RIA was developed that allowed the accurate measurement of low leptin levels in young lean children. With this assay, leptin proved to be a comparatively stable protein under common conditions of blood sampling and storage. Leptin levels increased in girls with age (r = 0.47, P < 0.0001), but decreased in boys (r = -0.34, P < 0.0001). An analysis according to pubertal stage showed a steady increase in girls between 2.51 micrograms/L (median) at Tanner stage 1 to 6.24 micrograms/L at Tanner stage 5. In boys, leptin levels were highest at Tanner stage 2 (2.19 micrograms/L) and declined thereafter to 0.71 microgram/L at Tanner stage 5. A strong exponential relationship was observed for leptin levels with body mass index (BMI) and percentage body fat as determined by bioelectric impedance measurements in a subgroup of subjects. This relationship was similar between boys and girls at Tanner stages 1 and 2. In boys, there was a significant decline of leptin at a given BMI with further progression of puberty that was much less pronounced in girls. Although the relative increase of leptin with BMI and percent body fat was the same in both genders, the absolute values at a given BMI or percent body fat were significantly lower in boys in late puberty and in adolescents. In boys, but not in girls, there was an inverse correlation with testosterone concentrations (r = -0.43, P < 0.0001), which explained 10.5% of the variation of leptin levels in a multiple regression model. Since BMI proved to be the major influencing variable, reference ranges were constructed using a best-fit regression line of the form leptin = a*e(b*BMI) and stratifying ranges according to gender and pubertal stage. In conclusion, these data suggest that 1) plasma leptin levels increase in girls and decrease in boys after Tanner stage 2 as the pubertal development proceeds; 2) they show a significant gender difference especially in late puberty and adolescence, even after adjustment for BMI or percent body fat; 3) the lower levels in males may be explained at least in part by a suppressive effect of androgens; 4) reference ranges with BMI as the independent variable should be stratified according to gender and pubertal stage.

Adipose Tissue↗
PubMed1996

Neuropeptide Y 3-36 is an endogenous ligand selective for Y2 receptors.

Neuropeptide Y (NPY 1-36) binds to Y1 and Y2 receptors with similar affinity. No endogenous molecular form of NPY with selectivity for Y1 or Y2 receptors has been described so far. We report the presence of an endogenous fragment of NPY in porcine brain, NPY 3-36, which lacks the amino-terminal dipeptide Tyr-Pro of NPY 1-36. NPY 3-36 accounts for 35% of NPY-like immunoreactivity in porcine brain. We have compared binding of NPY 3-36 and NPY 1-36 in model systems of Y1-like (SK-N-MC cells) and Y2-like receptors (CHP234 cells). NPY 3-36 and NPY 1-36 had similarly high affinity for Y2-like receptors on CHP234 cells, but NPY 3-36 had a 1000-fold lower affinity than NPY 1-36 for Y1-like receptors on SK-N-MC cells. Thus amino-terminal cleavage of NPY 1-36 generating NPY 3-36 converts an unselective Y1/Y2 receptor ligand into a highly Y2 selective ligand. This may be a means of fine tuning NPY biological actions.

Animals↗
PubMed1996

Two novel mutations in the aquaporin-2 and the vasopressin V2 receptor genes in patients with congenital nephrogenic diabetes insipidus.

The vasopressin V2 receptor (V2R) and the aquaporin-2 genes of two unrelated male patients with congenital nephrogenic diabetes insipidus were analyzed. The V2R gene of the patient of family 1 had the wild-type sequence. Consequently, the coding region of the aquaporin-2 gene including the exon-intron junctions was sequenced. A novel G to T transversion at codon 202, predictive of an exchange of tryptophan 202 by cysteine, was identified. As the mutation occurs at G-1 of the 5' splice donor site of intron 3, aberrant splicing is also likely. The mutation involves one of the supposed water pore-forming loops. Therefore, both aberrant splicing and amino acid substitution are likely to result in a functionally defective protein. Sequencing of the complete V2R gene of the male patient of family 2 revealed a novel single-base deletion at codon 310 (delta C1001), shifting the reading frame to give an altered amino acid sequence beginning at codon 311. The mutation is unique in predicting a C-terminally extended protein (termination after codon 434 in the mutant receptor instead of codon 371 in the wild-type). The deduced mutant protein is likely to be nonfunctional since the amino acid sequence of the seventh transmembrane domain and the C-terminus is altered.

Amino Acid Sequence↗
PubMed1996

Increased neuropeptide Y-like immunoreactivity in cerebrospinal fluid and plasma of human immunodeficiency virus-infected patients: relationship to HIV encephalopathy.

Neuropeptide Y (NPY) is one of the most abundant and phylogenetically best conserved peptides in the mammalian central and peripheral nervous system where it plays an important role in the regulation of cardiovascular, metabolic, endocrine, immunological and cognitive functions. In a prospective study we determined neuropeptide Y-like immunoreactivity (NPY-LI) in cerebrospinal fluid (CSF) and plasma of 95 HIV-seropositive (n = 49) or seronegative (n = 46) patients who underwent diagnostic CSF examination. CSF and plasma NPY-LI but not noradrenaline concentrations were higher in seropositive than in seronegative patients indicating that raised levels of NPY-LI did not result from a non-specific activation of the sympathetic nervous system. Increased CSF NPY-LI was positively correlated with the degree of HIV encephalopathy (P < 0.01, Kruskal-Wallis test). Inflammatory disorders of the central nervous system and dementia due to other causes in HIV-seronegative patients were not associated with increased CSF NPY-LI. Our data suggest that increased CSF NPY-LI is a relatively specific phenomenon of HIV encephalopathy and may be involved in the pathogenesis of HIV-related neurological dysfunction. The links between retroviral infection and increased expression of neuropeptide Y and their pathophysiological implications remain to be determined.

AIDS Dementia Complex↗
PubMed1996

High leptin concentrations in serum of very obese children are further stimulated by dexamethasone.

Serum leptin concentrations and the levels of ob mRNA in adipocytes in obese humans are elevated. Hyperphagia and obesity are characteristics of hypercortisolism. We have therefore asked whether or not leptin levels were elevated in very obese children, and whether or not dexamethasone would increase leptin levels in obese children. A single dose dexamethasone suppression test was performed in ten obese children (5 girls, 5 boys; age 6 to 16 yrs, mean 12 +/- 1, median 12 yrs) to rule out hypercortisolism. Body mass index (BMI) in the ten children was calculated to be 27-45 kg/m2. Venous blood was sampled before dexamethasone was given in the evening and at 9.00 a.m. the following morning. Endogenous cortisol production was suppressed in all patients. Leptin levels, as measured by a newly developed specific radioimmunoassay, were 31.6 +/- 12.9 microg/l, range 19.2-59.9 microg/l before dexamethasone and 39.9 +/- 16.5 microg/l, range 26.3-80.3 microg/l after dexamethasone in the obese children (ANOVA, p = 0.01). Simple regression analysis revealed that serum levels correlated significantly with body mass index (r = 0.82, p < 0.001). Non-obese children (BMI < 27 kg/m2) had leptin levels between 0.1 and 33.3 microg/l, median 2.2 microg/l (N = 713). Girls (5.5 +/- 4.6 microg/l) (N = 401) had significantly higher leptin levels than boys (1.7 +/- 2.1 microg/l (N = 312) (p < 0.0001). We conclude that 1) high serum leptin concentrations are present in obese children. 2) A single dose of dexamethasone significantly increases the high leptin serum levels in these children. We hypothesize that glucocorticosteroids up-regulate leptin levels in the human.

Adolescent↗
PubMed1996

Dissociation of serum leptin concentration and body fat content during long term dietary intervention in obese individuals.

High serum leptin concentrations are observed in humans with high body fat content, indicating leptin resistance. Reducing leptin levels by lowering body fat could restore leptin sensitivity. Our study was designed to clarify the relationship between changes in body composition and circulating leptin during a long term hypocaloric diet. 12 obese women and 10 obese men were included in a 1000 kcal/day dietary intervention trial for 10 weeks. Body composition was measured by body impedance analysis and leptin by radioimmunoassay every 2 weeks. Body fat was reduced in females from 39.0 +/- 1.5 kg to 32.9 +/- 1.5 kg (p <0.001) and in males from 30.4 1.4 kg to 26.3 +/- 1.3 kg (p < 0.005). Plasma leptin decreased in females from 38.07 +/- 4.17 ng/ml to 18.90 +/- 2.75 ng/ml (p < 0.001) and in males from 10.58 +/- 2.16 ng/ml to 6.33 +/- 1.25 ng/ml (p < 0.001). Non-linear regression analysis of leptin kinetics showed a comparable one-phase exponential decline (y = Span x e(-K x x) + Plateau) in females (x +/- SEM: K = 0.48 +/- 0.01) and males (K = 0.60 +/- 0.01). Kinetics of body fat differed significantly from leptin data for females (K = 0.10 +/- 0.001, p < 0.001) but not for males (K = 0.27 +/- 0.02, p > 0.05). The leptin plateau was reached in both groups after 6- 8 weeks and the fat plateau in men after 10 weeks. Compared to healthy controls, some obese individuals had higher absolute values of leptin, but seemed to have a relative leptin deficiency when leptin was adjusted to body mass index according to a non-linear regression model of a large group of healthy women (n = 561) and men (n = 393). We conclude that during a long-term hypocaloric diet leptin uncouples from changes in body fat mass.

Adipose Tissue↗
PubMed1996

Characterization of ouabain-like immunoreactivity in human urine.

OBJECTIVE: To characterize ouabain-like immunoreactivity in human urine. METHODS: Sensitive radioimmunoassay for ouabain characterized by high-performance liquid chromatography. RESULTS: Serial dilution of urinary immunoreactive ouabain paralleled the standard curve, but not so plasma immunoreactive ouabain. Intravenous administration of 86 nmol (62.5 micrograms) ouabain caused a rapid rise in ouabain immunoreactivity in plasma of healthy volunteers with a maximum of 1.7 nmol/l 8 min after injection and returned to basal levels after 6 h. Ouabain immunoreactivity rose to 36 nmol/l in urine, suggesting that exogenously administered ouabain can be measured reliably in plasma and urine. Analytical reversed-phase high-performance liquid chromatography (isopropanol-propanol biphasic gradient; linear acetonitrile gradient) of sample extracts before assay demonstrated measurable amounts of ouabain-related material only in native urine, but not in plasma. When plasma and urine were spiked with ouabain standard or normal volunteers were injected with ouabain, the assay reliably measured ouabain. CONCLUSION: A substance closely related to ouabain can be detected in urine, but circulates, if at all, in small amounts in human plasma.

Adult↗
PubMed1996

Arginine vasopressin and renin in acutely ill children: implication for fluid therapy.

The hypothesis was tested that in young children when admitted to the hospital for acute illness, vasoactive hormone levels are raised. The plasma concentration of arginine vasopressin (AVP) and plasma renin activity (PRA) were measured in 103 acutely ill infants and children admitted to the hospital. Compared to 31 control children with elective surgery, plasma AVP and PRA levels were significantly elevated and plasma osmolality reduced in acute illness, indicating non-osmotic, cardiovascular AVP release. AVP and PRA elevations were found to be independent of the underlying diseases (e.g. respiratory infections, gastroenteritis, bacterial infections and the viral syndrome). Since cardiovascular AVP activation bears the risk of hyponatraemia in the case of hypotonic fluid therapy, initial fluid management should be performed with solutions containing half-normal or normal saline in acutely ill children.

Acute Disease↗
PubMed1996

Expression of IGFBP-2, -3, and -4 mRNA during differentiation of Caco-2 colon epithelial cells.

Local production of insulin-like growth factor (IGF)-binding proteins (IGFBP) determines the availability of the IGF to the cell and thus regulates IGF action. To find out whether specific patterns of IGFBP gene expression and IGFBP secretion were related to cell growth vs. cell differentiation, expression of IGFBP during long-term culture (21 days, n = 5) of the colon carcinoma cell line Caco-2 was investigated at the mRNA and protein levels. Markers of cell proliferation (increase in DNA, RNA, and protein content) and of differentiation [alkaline phosphatase (AP) activity; creatine kinase (CK) activity] were measured in parallel during long-term culture. IGFBP-2 mRNA expression correlated significantly with markers of proliferation (P < 0.05), whereas IGFBP-3 mRNA expression or IGFBP-3 secretion correlated with markers of differentiation (AP: r = 0.83, P < 0.001; CK: r = 0.45, P < 0.01). Similarly, IGFBP-4 mRNA expression correlated significantly with markers of differentiation (AP: r = 0.34, P < 0.05; CK: r = 0.35, P < 0.05). We hypothesize that IGFBP-3 and -4 are related to differentiation of Caco-2 cells, whereas IGFBP-2 is related to proliferation in Caco-2 cells.

Alkaline Phosphatase↗
PubMed1996

Airway nitric oxide in asthmatic children and patients with cystic fibrosis.

We evaluated the effects of asthma and cystic fibrosis on nitric oxide (NO) concentrations in the respiratory tract. NO levels in orally exhaled air and nasal gas samples were studied in 90 asthmatic patients (4-14 yrs), 67 patients with cystic fibrosis (CF) (5-32 yrs), and 68 controls (4-34 yrs). NO concentrations measured by chemiluminescene were correlated with the patient's vital capacity, forced expiratory volume in one second (FEV1) and specific airway resistance. In all groups, NO concentrations in orally-exhaled air correlated with the inhaled ambient NO (r = 0.85-0.91). At an ambient NO concentration of 0 parts per billion (ppb), asthmatic patients exhaled air with higher NO concentrations than cystic fibrosis patients and controls (8.0 +/- 6.1 ppb (n = 33); 4.9 +/- 2.6 ppb (n = 23); and 3.0 +/- 2.5 ppb (n = 37); respectively; p < 0.001). Similar results were obtained for ventilation-adjusted orally-exhaled NO. Nasal NO concentrations were lower in patients with CF (23 +/- 17 ppb) than in controls and asthmatics (96 +/- 47 and 103 +/- 64 ppb; p < 0.001). There was no relationship between nasal or oral NO and pulmonary function tests. Our results suggest that ambient NO levels influence NO concentrations in orally-exhaled air. Like adults, asthmatic children exhale more NO than their controls. Reduced nasal NO concentrations in patients with cystic fibrosis may reflect chronic epithelial cell damage or an increased mucosal barrier impeding NO diffusion into the airway.

Adolescent↗
PubMed1996

Coordinate expression of insulin-like growth factor II (IGF-II) and IGF-II/mannose-6-phosphate receptor mRNA and stable expression of IGF-I receptor mRNA during differentiation of human colon carcinoma cells (Caco-2).

Insulin-like growth factor II (IGF-II) has been implicated in the differentiation of skeletal muscle cells. In this study the putative role of IGF-II in epithelial cell differentiation was investigated. The expression of IGF-II, IGF-I receptor and IGF-II/mannose-6-phosphate receptor (IGF-II/M6P receptor) mRNA during spontaneous differentiation of the colon carcinoma cell line Caco-2 was measured. In addition, differentiation of Caco-2 cells during the cell culture period (days 1-21 in culture) was studied in parallel using morphological (light and scanning electron microscopy) and biochemical markers of growth (DNA, RNA and protein content, and beta-actin mRNA and glyceraldehyde phosphate dehydrogenase mRNA expression) and differentiation (alkaline phosphatase activity, carcinoembryonic antigen content). A putative correlation between the markers of growth and differentiation and IGF gene expression was studied using linear regression analysis. Expression of IGF-II mRNA and IGF-II/M6P receptor mRNA correlated significantly with the progress of differentiation, while the IGF-I receptor was stably expressed throughout the culture period and exhibited a crucial role for the survival of Caco-2 cells, as shown by blocking experiments employing the monoclonal anti-IGF-I receptor antibody alpha-IR3. We hypothesize that: IGF-II mRNA and IGF-II/M6P receptor mRNA are expressed in a coordinate fashion during the differentiation of Caco-2 cells; coordinate expression of IGF-II and of IGF-II/M6P receptor mRNA might point to a role for IGF-II as a growth stimulant and for the IGF-II/M6P receptor for a regulator of IGF-II bioavailability in differentiating cells; alternatively, high IGF-II/M6P receptor mRNA and protein expression in differentiated cells but low IGF-II binding to the IGF-II/M6P receptor point to an important intracellular role of this receptor type in differentiated colon epithelial cells; the IGF-I receptor mRNA is stably expressed during the differentiation process of Caco-2 cells; the IGF-I receptor protein seems to be a prerequisite for the survival of Caco-2 cells.

Caco-2 Cells↗