Biomedical subjects
Publications and source records attributed to W Rohde.
Ectopic expression of the barley homeobox gene BKn-3 conditions the development of epiphyllous flowers by de novo meristem formation. Various strategies are being described in an effort to identify genes whose products interact with the BKn-3 gene product or BKn-3 regulatory regions.
OBJECTIVE: The therapeutic success of low doses of glucocorticoids is mediated entirely by classical genomic effects, whereas that of high doses is also mediated to an as yet unknown extent by nongenomic effects. We assessed the relative therapeutic importance of these nongenomic effects in pulse therapy. METHODS: A [3H]dexamethasone radioligand binding assay was used to measure the number of glucocorticoid receptor sites (R, given as number of sites per cell) and glucocorticoid receptor binding affinity (Kd, given in nM) in peripheral blood mononuclear cells isolated from 26 healthy control blood donors and 27 patients with rheumatic diseases. Patients were divided into 4 groups on the basis of their glucocorticoid dose: 0 mg (Group A), < or = 0.25 mg (Group B), 0.25 to 1 mg (Group C), and > 1 mg (Group D) of prednisolone equivalent per kg per day. RESULTS: Sex independent normal values of 3605 +/- 1136 for R and 5.39 +/- 3.4 for Kd were found. At 5407 +/- 1968, the number of receptor sites in patients not receiving glucocorticoid therapy (Group A) was significantly higher than that of controls (p < 0.01). In patients receiving glucocorticoid therapy this value was reduced at 3855 +/- 866 (Group B), 3358 +/- 963 (Group C), and 2685 +/- 962 (Group D). The values in Groups C and D were significantly lower than those in untreated patients (p < 0.02). CONCLUSION: In pulse therapy doses of glucocorticoids that exceed receptor saturation are administered for several days, but in addition significant receptor downregulation occurs. Therefore, we assume an increase in the relative contribution of the nongenomic effects of glucocorticoids to the therapeutic success under these conditions.
Perinatal malnutrition and growth retardation at birth are suggested to be important risk factors for the development of overweight and syndrome X in later life. Underlying mechanisms are unknown. Body weight and food intake are regulated, e.g. by hypothalamic neuropeptidergic systems which are thought to be highly vulnerable to persisting malorganization due to perinatal malnutrition. To investigate possible consequences for hypothalamic cholecystokinin-8S (CCK-8S) in the offspring, pregnant Wistar rats were fed an 8% protein diet during pregnancy and lactation (low-protein group; LP) while control mothers (CO) received a 17% protein isocaloric standard diet. LP offspring displayed underweight at birth (P < 0.05) and during suckling (P < 0.001), while leptin levels were not altered. At weaning, under basal conditions CCK-8S was decreased in LP offspring in the paraventricular hypothalamic nucleus and arcuate hypothalamic nucleus (P < 0.05), as well as in the dorsomedial hypothalamic nucleus, lateral hypothalamic area and ventromedial hypothalamic nucleus (P < 0.01). In summary, these data indicate (1) an inhibition of the satiety peptide CCK-8S in main regulators of body weight and food intake in low-protein malnourished newborn rats; (2) no direct relationship of hypothalamic CCK-8S to circulating leptin at this age; and (3) no neurochemical signs of hypothalamic CCKergic dysregulation in this animal model at the age of weaning.
We recently reported on an elevation of neurons expressing the main orexigenic peptide neuropeptide Y (NPY) in the arcuate hypothalamic nucleus (ARC) of neonatally hyperinsulinaemic offspring of gestational diabetic mother rats (GD) at weaning. To investigate possible consequences, the long-term outcome of those animals was examined. At adult age, GD offspring showed hyperphagia (p < 0.001), basal hyperinsulinaemia (p < 0.05) and impaired glucose tolerance (p < 0.05), and were overweight (p < 0.01). This was accompanied by an elevated number of NPY neurons (p < 0.001) and galanin neurons (p < 0.001) in the ARC in adult GD offspring under basal conditions. These findings support our hypothesis on perinatally acquired, persisting malformation and/or malprogramming of peptidergic hypothalamic neurons in the offspring of GD mothers, possibly promoting the development of overweight and diabetogenic disturbances during life.
Overnutrition during critical developmental periods is suggested to be a risk factor for obesity and associated metabolic disorders in later life. Underlying mechanisms are unknown. Neuropeptides are essentially involved in the central nervous regulation of body weight. For instance, hypothalamic galanin (GAL) is a stimulator of food intake and body weight gain. To investigate long-term consequences of early postnatal overfeeding, the normal litter size of Wistar rats (n=10; controls) was reduced from day 3 to day 21 of life to only 3 pups per mother (small litters, SL; overnutrition). Throughout life, SL rats displayed hyperphagia (p<0.01), overweight (p<0.0001), hyperinsulinemia (p<0.01), impaired glucose tolerance (p<0.001), elevated triglycerides (p<0.001), and an increased systolic blood pressure (p<0.05). In adulthood, an increase of GAL-neurons in the arcuate hypothalamic nucleus (ARC) was found (p<0.001), positively correlated to body weight (p<0.001). A second experiment revealed hyperinsulinemia (p<0.001) and increased hypothalamic insulin levels (p<0.05) in SL rats during early postnatal life. Already on day 21 of life, i.e., at the end of the critical hypothalamic differentiation period, in SL rats the number of GAL-neurons was increased in the ARC (p<0.001), showing a positive correlation to body weight and insulin (p<0.05). In conclusion, neonatally acquired persisting malformation of hypothalamic galaninergic neurons, induced by early overfeeding and hyperinsulinism, might promote the development of overweight and syndrome X-like alterations during life.
Perinatal overfeeding is a risk factor for overweight and diabetes during life. Underlying pathophysiological mechanisms are unclear. The peptide galanin is suggested to stimulate food intake by acting within the paraventricular hypothalamic nucleus (PVN). In early postnatally overfed rats overweight and hyperinsulinemia were observed, accompanied by an increased number of galanin-positive neurons in the PVN at weaning. Our results might indicate malformation of hypothalamic galaninergic neurons due to neonatal overfeeding and hyperinsulinism, respectively, in rats.
Mono- and polyclonal antibodies directed against different domains of the potato leafroll luteovirus (PLRV) P1 (ORF1) protein were applied to the analysis of P1 expression during PLRV replication in planta. Western analyses detected P1 and a protein of approximately 25 kDa (P1-C25) that accumulated to readily detectable amounts in PLRV-infected plants, but was not detected by in vitro cell-free translation of P1. P1-C25 represents the C-terminus of P1 and is a proteolytic cleavage product produced during P1 processing. On the basis of its molecular weight, the N-terminus of P1-C25 is either identical to or located adjacent to the previously identified PLRV genome-linked protein, VPg. P1-C25 is not associated with virus particles, and subcellular localization experiments detected P1-C25, but not P1, in the membrane and cytoplasmic fractions of PLRV-infected cells. In addition, P1-C25 exhibits nucleic acid-binding properties. On the basis of its biosynthesis, localization and biochemical properties, P1-C25 may facilitate the formation of P1/PLRV RNA complexes in which the spatial proximity allows for covalent bond formation between PLRV RNA and VPg.
The hypothalamic-pituitary-adrenal (HPA) axis is stimulated during immune and inflammatory processes. Interleukin 1beta (IL-1beta) and lipopolysaccharide (LPS) are known to be potent stimulators of this axis. During postnatal development, the rat seems to be hyporesponsive to many stimuli. The effects of repeated systemic injections of IL-1beta and LPS on the HPA axis were investigated in neonatal rats. IL-1beta (0.02 microg/pup, administered twice daily from postnatal day 1 to 4) induced marked elevation in plasma corticosterone (CORT) level as compared to controls and LPS groups (0.4 microg or 1.2 microg LPS/pup, injected once daily from postnatal day 1 to 4). Adrenal wet weight was significantly higher, thymus weight was significantly lower. In contrast to the organ weights, there were no differences in CORT concentrations between LPS-exposed groups and controls. However, the weights of the adrenals in rats treated with LPS were significantly increased in a dose-dependent manner as compared to controls. The high LPS dose was associated with significantly lower thymus weights as compared to controls and 0.4 microg LPS rats. Thymus weights were significantly lower following IL-1beta- than LPS-administration. It is supposed that a developing endotoxin tolerance could account for the observed absence of CORT rise after the last LPS injection.
In former studies, a temporary, intrahypothalamically localized hyperinsulinism during brain development was shown to result in overweight and metabolic disturbances during later life in rats. Therefore, we tested the hypothesis whether intrahypothalamic insulin treatment during early postnatal life may lead to hypothalamic morphological alterations, i.e., of numerical density of neurons and area of neuronal nuclei or area of neuronal cytoplasm, in this animal model. For this purpose, on the 8th day of age in Wistar rats a long-acting insulin was bilaterally applicated stereotactically into the hypothalamus (12 mIU on each side), while in controls the insulin-free agar-vehicle was given only. By computer-assisted morphometric analysis on the 15th day of life a decrease of the mean area of neuronal nuclei and the mean nucleus-cytoplasm-ratio within the VMN of the insulin-treated animals was observed, as compared to control rats (P < 0.05), while no significant alterations were found in the lateral hypothalamic area (LHA). Analysis of topographically distinct parts of the VMN revealed significant reductions of the mean area of neuronal nuclei (P < 0.001) and nucleus-cytoplasm-ratio (P < 0.05) in the anterior part of the VMN (VMNpa). Furthermore, in the ventrolateral part (VMNpv) a decreased mean neuronal density was observed in the insulin group (P < 0.01). In contrast, the dorsomedial part of the VMN (VMNpd) displayed an increased mean neuronal density in the insulin-treated animals (P < 0.05). In the dorsomedial hypothalamic nucleus (DMN) a significant increase of the mean area of neuronal nuclei (P < 0.01) and the area of neuronal cytoplasm were observed (P < 0.001). These alterations were accompanied by a significantly elevated mean numerical density of astrocytes (positive for glial fibriallary acidic protein; GFAP+) within the periventricular hypothalamic area (PER) of the insulin-treated rats (P < 0.05). These observations speak for a varying vulnerability of LHA, DMN and distinct parts of the VMN to hyperinsulinism during early development, possibly leading to a disturbed organization and, consecutively, permanent dysfunction of these morphologically connected and functionally interacting hypothalamic nuclei.
Early postnatal overnutrition is a risk factor for obesity in juvenile and adult life. Underlying pathophysiological mechanisms are still unclear. Hypothalamic neuropeptides are decisively involved in the regulation of body weight and food intake. In this study, we investigated consequences of early postnatal overnutrition, as compared to normo-and undernutrition, on NPY within the arcuate nucleus and paraventricular nucleus (PVN). The normal litter size of Wistar rats was adjusted on the third day of life from 10 pups (normal litters, NL; normonutrition) to only three newborns (small litters, SL; overnutrition) or 18 pups per mother (large litters, LL; undernutrition). SL rats developed clear overweight until the day 21 of life (P<0.0001), as well as hyperleptinaemia (P<0.001), and hyperinsulinaemia (P<0.01). LL rats were underweight and had decreased leptin and insulin concentrations. Using radioimmunoassay, NPY contents were determined in hypothalamic micropunches, and immunocytochemistry for NPY was performed in serial hypothalamic sections on day 21 of life. While in the underweight, hypoleptinaemic, and hypoinsulinaemic LL rats increased concentrations of NPY in the arcuate nucleus and PVN were observed, no decrease in NPY content was found in the overweight, hyperleptinaemic, and hyperinsulinaemic SL rats. Moreover, the percentage of NPY-immunopositive neurones per total number of neurones was increased not only in the LL rats, but also in the SL rats. Since the NPY system is functionally mature already at this age, these findings might indicate an acquired resistance of the hypothalamic NPY system to increased levels of insulin and/or leptin in early postnatally overfed SL rats.
Insulin is a potent modulator of central nervous development and is suggested to influence the differentiation and maturation of hypothalamic structures involved in the regulation of body weight and metabolism. Hyperinsulinemic offspring of mothers with impaired glucose tolerance during pregnancy (gestational diabetes, GD) have an increased risk to develop overweight and diabetes mellitus during life, while the underlying pathophysiological mechanisms are still unknown. To investigate the effects of perinatal hyperinsulinism on the organization of hypothalamic regulators of body weight and metabolism, GD was induced in rats by application of streptozotocin on the day of conception (25 mg/kg, i.p.). On the 21st day of life, offspring of GD rats were overweight (p < 0.05) and hyperinsulinemic (p < 0.01). Using computer-assisted morphometric measurements, significantly decreased mean areas of neuronal nuclei and neuronal cytoplasm within the paraventricular hypothalamic nucleus (PVN; p < 0.01) and the ventromedial hypothalamic nucleus (VMN; p < 0.05) were observed in GD offspring. Analysis of topographically distinct parts revealed that these alterations particularly occurred in the parvocellular part of the PVN, as well as in the anterior, central, and dorsomedial part of the VMN. No morphometric alterations were found within the lateral hypothalamic area and the dorsomedial hypothalamic nucleus. In the arcuate hypothalamic nucleus, the mean area of neuronal cytoplasm was decreased (p < 0.05), while the number of neurons expressing tyrosine hydroxylase was clearly elevated (p < 0.002). For astrocytes, a tendency towards an increased glia/neuron ratio was observed in the periventricular hypothalamic area. These observations suggest disturbed differentiation and organization of distinct hypothalamic nuclei and subnuclei, respectively, in hyperinsulinemic offspring of GD rats, possibly leading to dysfunctions of hypothalamic regulators of body weight and metabolism which might contribute to the lifelong increased risk to develop overweight and diabetogenic disturbances.
OBJECTIVE: Since the offspring of gestational diabetic mothers (GD) is at increased risk to develop obesity and diabetogenic disturbances later in life, while pathophysiological mechanisms responsible are unclear, to investigate long-term consequences of neonatal hyperinsulinism occurring characteristically in GD offspring. METHODS: Newborn Wistar rats received daily subcutaneous injections of a long-acting insulin from the 8th to 11th day of life (IRI), while in controls (CO) NaCl was applied. Body weight was recorded throughout life. Glucose tolerance test was performed on the 140th day of life (1.5 g/kg glucose injected i.p. after an overnight fast and blood samples were taken up to 90 min from retroorbital plexus). On the 240th day of life, the vulnerability to a single "subdiabetogenic" dose of streptozotocin (STZ; 25 mg/kg body weight) was tested. Blood samples for estimating glucose levels were taken before STZ, and subsequently on days 2, 7, 14, 21, and 28 after STZ. RESULTS: IRI rats developed overweight during juvenile life until adulthood (P<0.001), characterized by a clear elevation of the Lee obesity index (P<0.005), and associated with basal hyperglycaemia (P<0.05), hyperinsulinaemia (P<0.05), as well as an increased insulin/glucose-ratio as a measure of insulin resistance (P<0.005). Impaired glucose tolerance occurred in early adulthood, and increased vulnerability to a "subdiabetogenic" dose of streptozotocin (see above), leading to significant hyperglycaemia (P<0.05), was evaluated in the 9th month of age. Accompanied by a transient reduction of hyperinsulinaemia during a period of 21 days, Lee obesity index and insulin/glucose-ratio decreased significantly after STZ treatment in IRI rats (P<0.01). CONCLUSIONS: Overweight and increased diabetes susceptibility in adulthood due to temporary hyperinsulinism during a critical period of postnatal life are suggested to be a consequence of acquired dysregulation and overstimulation, respectively, of the pancreatic insulin secretion in rats.
The offspring of diabetic mothers is at increased risk to develop obesity and diabetogenic disturbances during life. Pathophysiological mechanisms responsible are unclear. Neuropeptide Y (NPY) is an important hypothalamic stimulator of food intake and body weight gain, and its levels are decreased by elevated insulin. In neonatally hyperinsulinaemic offspring of diabetic mother rats, hypothalamic insulin level was significantly increased at birth (p < 0.01). At weaning, i.e. at the end of the critical hypothalamic differentiation period, a significantly increased number of NPY-positive neurons (p < 0.01) appeared in the arcuate hypothalamic nucleus. In conclusion, an increase in the number of NPYergic neurons in the hypothalamus, possibly due to hypothalamic malformation and/or perinatally acquired hypothalamic insulin resistance, might contribute to the development of obesity and metabolic disturbances in the offspring of diabetic mothers.
Cholecystokinin (CCK) is suggested to be involved, e.g. in the central nervous modulation of food intake, possibly by acting within specific hypothalamic nuclei. Perinatal overnutrition predisposes to permanent obesity and hyperphagia, while underlying mechanisms are unclear. By reducing the litter size from the 3rd to 21st day of life, early overnutrition was induced in newborn rats. At weaning, clear overweight (P < 0.001), hyperglycaemia (P < 0.05), hyperinsulinaemia (P < 0.001), and insulin resistance (P < 0.001) occured. These early signs of obesity were associated with a significantly decreased number of CCK-positive neurons in the paraventricular hypothalamic nucleus (P < 0.002). In conclusion, due to neonatal overfeeding malformation of CCKergic neurons at the end of the critical hypothalamic differentiation period occurs. Long-term consequences on CCK-related neuroendocrine regulations could be suggested, including those affecting food intake and body weight gain.
Catecholamines are essential organizers of the developing brain. Throughout life, they are involved, e.g., in the regulation of body weight and metabolism by specific hypothalamic nuclei, which are suggested to be highly vulnerable to maternal gestational hyperglycemia. By application of streptozotocin (30 mg/kg, i.p.) gestational diabetes (GD) was induced in female rats. On the 1st day of life, male GD offspring were underweight (P<0.05) and hyperglycemic (P<0.05), while on the 21st day of life decreased body weight (P<0.001) and elevated pancreatic insulin (P<0.01) were observed. Using HPLC with electrochemical detection, hypothalamic catecholamines were determined in the newborns, and quantitative immunocytochemistry for tyrosine hydroxylase (TH) was performed. At birth, a tendency towards increased levels of norepinephrine (NE) and dopamine (DA) in the whole hypothalami of GD offspring was observed. In the 21-day-old offspring of GD mothers, NE was significantly increased in the ventromedial hypothalamic nucleus (VMN; P<0.05) and the lateral hypothalamic area (LHA; P<0.05), while DA was significantly elevated in the paraventricular hypothalamic nucleus (PVN; P<0.05) and the LHA (P<0.05). The NE/DA-ratio was found to be decreased in the PVN of GD offspring (P<0.01). Moreover, numerical density of TH-positive neurons was clearly increased within the parvocellular division of the PVN (P<0.0001) as well as in the periventricular hypothalamic area (PER; P<0.05). These data suggest specific alterations of catecholaminergic systems within hypothalamic regulators of body weight and metabolism during early development in the offspring of gestational diabetic mother rats.
The genetic information of potato leafroll virus (PLRV), a typical member of the subgroup 2 luteoviruses, is contained in a single-stranded (+) sense RNA of approximately 5.9 kb. A single subgenomic RNA (sgRNA1) of approximately 2.3 kb has been characterized as the mRNA for the 3' clustered viral open reading frames ORF3, ORF3/5 and ORF4. Here we demonstrate by Northern blot analyses of polysomal RNAs from PLRV-infected Solanum tuberosum and Physalis floridana plants that, as with luteoviruses belonging to subgroup 1, in planta synthesis of a second 0.8 kb subgenomic RNA (sgRNA2) increases the complexity of subgroup 2 luteoviral genomes significantly. PLRV-specific hybridization probes as well as primer extension experiments map sgRNA2 to the 3'-end of the PLRV RNA genome (positions 5190-5987). Similarly, for the closely related cucurbit aphid-borne yellows virus (CABYV) a sgRNA2 of similar size and position (positions 4888-5669) was identified. PLRV sgRNA2 may code for two viral proteins of 7.1 (ORF6) and 14 kDa (ORF7) respectively, while the CABYV proteins are 8.7 (ORF6) and 8.3 kDa (ORF7) in size, with PLRV ORF7 displaying nucleic acid binding activity. In vivo experiments by transient expression of chimeric GUS fusions in potato protoplasts demonstrated that sgRNA2 functions as a bicistronic mRNA with high expression of ORF6 and low translational efficiency for synthesis of ORF7.
UNLABELLED: Infantile cystinosis, a rare lysosomal storage disease of cystine, leads to Fanconi syndrome and end-stage renal failure. After renal transplantation, no recurrence of the disease occurs in the graft, but other organ involvement becomes evident later in life. Diabetes mellitus has been associated with cystinosis, but the mechanisms of impaired glucose tolerance have not yet been characterized. Here, we studied glucose tolerance, glucose constant decay (k-values), insulin and C-peptide by intravenous glucose tolerance test (IVGTT) in eight patients with infantile cystinosis (three with impaired GFR (CRF) and five after kidney transplantation (KTX)). For comparison, 15 age-matched children with CRF and 15 age-matched KTX patients were analysed. Both early and second insulin secretion phases were diminished in patients with infantile cystinosis, whereas in CRF, k-values were no different from control patients. After renal transplantation, k-values were significantly lower in cystinotic patients with a markedly reduced early insulin secretion phase. There was a significant negative correlation between k-values and age in patients with cystinosis. Repetitive IVGTTs in these patients demonstrated progressive but rather slow loss of first phase insulin secretion and C-peptide production, suggesting a slowly reducing secretion potential of the beta cell due to cystine storage. CONCLUSION: Unlike type I diabetes mellitus, glucose intolerance in patients with infantile cystinosis is characterized by a slow, progressive loss of insulin secretion and C-peptide production. For these patients, the data indicate a 50% risk of developing glucose intolerance by the age of 18 years. We recommend to perform intravenous glucose tolerance tests at 5-year intervals.
Hypothalamic structures are decisively involved in the regulation of body weight and metabolism. In syndrome X, complex metabolic alterations are present, which in women are found to be associated with disturbances of reproductive function and altered androgen levels. In previous experiments in rats, it was shown that a temporary intrahypothalamic hyperinsulinism during early life predisposes to overweight and diabetogenic disturbances later in life, associated with disorganization of hypothalamic regulatory centers. To investigate the possible long-term consequences of elevated peripheral insulin levels during ontogenesis, the following experiment was performed. Newborn female Wistar rats were treated during neonatal life with daily subcutaneous injections of long-acting insulin ([IRI group] 0.3 IU on days 8 and 9 of life and 0.1 IU on days 10 and 11 of life), whereas control animals (CO) received daily NaCl injections. This temporary exposure to increased insulin levels during a critical developmental period resulted in an increased body weight gain including juvenile life and adulthood (P < .01), accompanied by hyperinsulinemia (P < .01), impaired glucose tolerance (P < .05), and increased systolic blood pressure in adulthood (P < .025). No significant alterations were detected either in cyclicity and fertility or in the levels of testosterone, androstenedione, or dehydroepiandrosterone (DHEA) in IRI rats. Morphometric evaluation of hypothalamic nuclei showed a reduced numerical density of neurons (P < .025) and a decreased neuronal volume density (P < .025) within the ventromedial hypothalamic nucleus (VMN) of the IRI rats, whereas the antagonistic lateral hypothalamic area (LHA) was morphometrically unchanged. Newborn offspring of IRI rats (F1 generation) were overweight (P < .05) and had an increased pancreatic insulin concentration (P < .02). In conclusion, perinatal hyperinsulinism seems to predispose to the later development of syndrome X-like changes in female rats, possibly due to impaired organization of hypothalamic regulators of body weight and metabolism.