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Biomedical subjects

H Jasper

Publications and source records attributed to H Jasper.

At least 19 recordsLinked to original sources
PubMed2001

The genomic response of the Drosophila embryo to JNK signaling.

During Drosophila development, the Jun N-terminal kinase signal transduction pathway regulates morphogenetic tissue closure movements that involve cell shape changes and reorganization of the actin cytoskeleton. We analyzed the genome-wide transcriptional response to activation of the JNK pathway in the Drosophila embryo by serial analysis of gene expression (SAGE) and identified loci encoding cell adhesion molecules and cytoskeletal regulators as JNK responsive genes. The role of one of the upregulated genes, chickadee (chic), encoding a Drosophila profilin, in embryogenesis was analyzed genetically. chic-deficient embryos fail to execute the JNK-mediated cytoskeletal rearrangements during dorsal closure. This study demonstrates a transcriptional mechanism of cytoskeletal regulation and establishes SAGE as an advantageous approach for genomic experiments in the fruitfly.

Actins↗
PubMed2000

Differences in anthropometric parameters and the IFG-I-IGFBP3 axis between liver and renal transplant children.

BACKGROUND: Growth can be differently altered after liver and renal transplantation (Tx) in childhood. METHODS: We compared graft function, linear growth, immunosuppression and serum IGF-I (RIA) and IGFBP3 (IRMA) concentrations in 15 liver (5.6+/-1.1 years old) and 17 renal (7.4+/-0.1 years old) Tx patients who were followed for 4-6 years. RESULTS: Graft function was normal post-liver Tx, although in renal recipients creatinine clearance decreased significantly during follow-up. Liver Tx children presented an increase in mean height of 0.92+/-0.2 SDS (P<0.01) beyond the 2nd year post-Tx, although in renal Tx patients height SDS did not improve. Immunosuppressive corticoid dosage could be decreased and discontinued in liver Tx patients, while in renal recipients it was maintained between 0.18+/-0.01 and 0.16+/-0.02 mg/kg/day. At 3.7+/-0.4 years post Tx, liver Tx patients presented higher mean serum IGF-I level, lower mean serum IGFBP3 value, leading to a higher mean IGF-I/IGFBP3 molar ratio, P<0.001. CONCLUSIONS: We found that while catch up growth coud be achieved after liver Tx, height SDS did not improve after renal Tx. This may be related to a reduced renal graft function and/or to differences in immunosuppressive corticoid dosage. In children with renal transplants a challenge for the future will reside in making it possible to substitute steroid therapy without altering graft function.

Adolescent↗
PubMed2000

Effect of deflazacort versus methylprednisone on growth, body composition, lipid profile, and bone mass after renal transplantation. The Deflazacort Study Group.

Kidney function, growth velocity, weight/height ratio, body composition, lipid profile, and bone mass were studied in a randomized, multicenter trial of deflazacort versus methylprednisone in 27 prepubertal patients with kidney transplantation. Methylprednisone (0.20+/-0.03) was replaced by deflazacort (13 patients, 0.30+/-0.03 mg/kg per day). After 12 months, creatinine clearance decreased significantly only during methylprednisone therapy. Growth velocity increased only in patients treated with deflazacort from 3.3+/-0.6 to 5.6+/-0.5 cm/year. Serum levels of several components of the insulin-like growth factor axis did not change. Weight/height ratio was increased in methylprednisone-treated patients (P<0.05) and decreased in deflazacort-treated patients (P<0.005). Lean body mass increased in both groups (P<0.005). Fat body mass and serum leptin increased only in methylprednisone-treated patients (P<0.025). Total cholesterol and low-density lipoprotein-cholesterol increased in methylprednisone-treated patients by 9.9% (P<0.05) and 12.5% (P<0.025). High-density lipoprotein-cholesterol increased by 21% (P<0.005) and apolipoprotein B decreased by 11% (P<0.005) in deflazacort-treated patients. Total skeleton and lumbar spine bone mineral density decreased in both groups, but at 1 year methylprednisone-treated patients had lost 50% more bone. Bone mineral content decreased only in methylprednisone-treated patients (P<0.01). Our data suggest that substituting deflazacort for maintenance methylprednisone might prevent height loss, excessive bone loss, and fat accumulation; and leads to an improvement in the lipoproteins of these children.

Body Composition↗
PubMed1999

Evaluation of disease activity by IGF-I and IGF binding protein-3 (IGFBP3) in acromegaly patients distributed according to a clinical score.

UNLABELLED: To facilitate the estimation of acromegalic activity a prospective study was done comparing, against a clinical score, the effectiveness of serum IGF-I, IGFBP3 and the IGF-I/IGFBP3 molar ratio. Sixty nine observations were distributed in three groups: Group I=patients before surgery; group II=patients improved but still clinically active; group III=patients clinically inactive. Suppression of serum GH levels one hour after an oral glucose load was in agreement with the clinical score in 21/22 observations. Increases in serum IGF-I and IGFBP3 levels were similarly frequent: both 100% in group I, 80% and 95% in group II, 9% and 36% in group III, respectively. The frequency of abnormal molar ratios was 95%, 40% and 0% in the same groups. Log IGF-I, log IGFBP3, and log molar ratio correlated significantly with the clinical scores (r=0.873, r=0.692, and r=0.829, respectively). CONCLUSIONS: The IGF-I/IGFBP3 molar ratio was not better than either IGF-I or IGFBP3 in detecting activity in the three groups of patients studied. Both IGF-I and IGFBP3 appear comparably useful for the diagnosis and follow-up of acromegalic patients. Since IGF-I is a more biologically meaningful parameter it might be preferable.

Acromegaly↗
PubMed1998

SAF-B protein couples transcription and pre-mRNA splicing to SAR/MAR elements.

Interphase chromatin is arranged into topologically separated domains comprising gene expression and replication units through genomic sequence elements, so-called MAR or SAR regions (for matrix- or scaffold-associating regions). S/MAR regions are located near the boundaries of actively transcribed genes and were shown to influence their activity. We show that scaffold attachment factor B (SAF-B), which specifically binds to S/MAR regions, interacts with RNA polymerase II (RNA pol II) and a subset of serine-/arginine-rich RNA processing factors (SR proteins). SAF-B localized to the nucleus in a speckled pattern that coincided with the distribution of the SR protein SC35. Furthermore, we show that overexpressed SAF-B induced an increase of the 10S splice product using an E1A reporter gene and repressed the activity of an S/MAR flanked CAT reporter gene construct in vivo . This indicates an association of SAF-B with SR proteins and components of the transcription machinery. Our results describe the coupling of a chromatin organizing S/MAR element with transcription and pre-mRNA processing components and we propose that SAF-B serves as a molecular base to assemble a 'transcriptosome complex' in the vicinity of actively transcribed genes.

3T3 Cells↗
PubMed1998

Relationship between non-enzymatic glycosylation and changes in serum insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 levels in patients with type 2 diabetes mellitus.

The possible occurrence of increased non-enzymatic glycosylation of serum insulin-like growth factor binding protein-3 (IGFBP-3) in vivo and the changes that would simultaneously occur in serum levels of IGFBP-3 and insulin-like growth factor-1 (IGF-I) were investigated. We measured levels of IGF-I and IGFBP-3 and the degree of glycation of total serum protein and IGFBP-3, in serum samples obtained from patients with poorly controlled non-insulin-dependent diabetes (type 2) and from age-matched non-diabetic controls. Type 2 diabetic patients had significantly higher glycated serum protein (GlyP) levels. GlyP significantly correlated with age in the control (r = 0.315, P<0.05) but not in the type 2 diabetes group. Control and diabetic subjects had comparable serum IGF-I levels and in both groups IGF-I levels tended to decrease with age (r = -0.567, P<0.001 and r = -0.465, P<0.05 for control and type 2 diabetic subjects, respectively). In the type 2 diabetes group, IGF-I levels showed a negative correlation with serum GlyP values (r = -0.476, P<0.05). Type 2 diabetic and control patients had comparable serum IGFBP-3 levels, which were significantly higher in diabetic patients in the older age subgroups. A negative correlation was found between IGFBP-3 levels and age in the control (r = -0.705, P<0.001) and in the type 2 diabetes groups (r = -0.463, P<0.05). A significant negative correlation was found between IGFBP-3 levels and GlyP in control (r = -0.449, P<0.002) but not in type 2 diabetic subjects. The mean glycated IGFBP-3 (GlyIGFBP-3) levels were higher in the oldest type 2 diabetic patients. In these patients, GlyIGFBP-3 was negatively associated with IGF-I levels (r = -0.447, P<0.05). The IGF-I/IGFBP-3 molar ratio was significantly reduced in the 46-60-year-old type 2 diabetic group, whereas the IGF-I/IGFBP-3 ratio was positively and significantly correlated with GlyP levels only in the control group (r = 0.489, P<0.01). Our results show that: a) increased non-enzymatic glycosylation of IGFBP-3 occurs in vivo; and b) this effect is accompanied by an increase in IGFBP-3 levels. These results suggest that the IGF-I/IGFBP-3 system is another target for the metabolic derangements of type 2 diabetes. Its alterations might play a role in diabetic complications.

Adult↗
PubMed1997

Effects of deflazacort immunosuppression on long-term growth and growth factors after renal transplantation.

Deflazacort is an oxazoline compound derived from prednisolone. We studied changes in kidney function, growth velocity, weight/height ratio, insulin-like growth factor (IGF-I), and IGF binding proteins before and after substitution of deflazacort for methylprednisone in 27 transplanted patients aged 3.1-20 years. Methylprednisone (mean +/- SEM 0.17 +/- 0.01 mg/kg per day) was replaced by deflazacort (0.29 +/- 0.01 mg/kg per day) for a period of 1-5 years. Calculated creatinine clearance did not change significantly during deflazacort treatment. Growth velocity increased from 2.6 +/- 0.5 cm/year to 5.2 +/- 0.7 cm/year (1st year) in 14 prepubertal patients. After 4 years of deflazacort treatment, height standard deviation score for chronological age did not change in 7 prepubertal patients. Mean weight/height ratio decreased by 50% (1st year) and remained reduced during follow-up. Serum IGF-I, IGF binding protein-3 (IGFBP3), IGF/IGFBP3 molar ratio, and IGF-I and II binding capacities showed no significant change; however in 5 of 6 patients IGFBP2 decreased during deflazacort therapy. Our findings suggest that immunosuppressive treatment with deflazacort is as effective as methylprednisone and may lead to an improvement in the growth prognosis of children with renal transplantation.

Adolescent↗
PubMed1994

Biochemical markers of acromegalic activity.

Against a clinical score we compared the effectiveness of three biochemical markers of acromegalic activity: a) growth hormone response to i.v. thyrotropin-releasing hormone, b) growth hormone suppression one hour after an oral glucose load, c) basal plasma IGF-I levels. In 21 patients we obtained 39 observations comprising the four parameters. According to the clinical score, patients were divided into three groups: group I = patients before surgery; group II = improved but still clinically active; group III = clinically inactive. After i.v. thyrotropin-releasing hormone, abnormal observations increased although the patients improved clinically, so that this test was excluded from statistical analysis. Abnormalities in plasma IGF-I levels and in GH suppression after oral glucose were similarly frequent in the groups studied: both 100% in group I, both 71.4% in group II, 27.3% vs. 18.2% in group III (p > 0.05). Both tests made exactly the same contribution to the other's capacity to detect acromegalic activity: 3 out of 39 observations (5.1%). We conclude that basal plasma IGF-I is the single best biochemical marker to detect acromegalic activity, since it is statistically at least as useful as growth hormone suppression, and is far more simple for the patient and the laboratory.

Acromegaly↗
PubMed1993

Comparative study of IGFBP properties in toad and rat sera.

The levels of IGF-I have been simultaneously measured by radioimmunoassay in samples of the toad Bufo arenarum and of normal male Wistar rats. In addition, the different fractions of IGF-I binding proteins (IGFBP) and their binding properties have been identified by ligand blot and Scatchard analysis in the serum of both species. In the toad, we have measured levels of IGF-I (2.78 +/- 0.48 ng/ml) similar to those previously reported in amphibians but far below those found in rats. IGFBP levels were estimated at 129 +/- 23 and 4249 +/- 321 pg/ml in toad and rat serum samples. Two main IGFBP fractions of 30-34 kDa, accompanied by a minor component of 24 kDa and seldom by another of 40 kDa, were identified in toad serum. In rat serum--as already reported--three bands of 40, 30, and 24 kDa were identified, the first being the main component and the last the minor one. The Scatchard analysis of a competitive binding assay showed two types of binding sites in toad serum: one of high affinity-low capacity (Ka1 = 1.6 x 10(10) M-1; R1 = 1.2 x 10(-11) M) and another with low affinity-high capacity (Ka2 = 1.9 x 10(8) M-1; R2 = 1.9 x 10(-10) M). The percentage fraction of these binding sites occupied by IGF-I was 13.5%. The figures for K1 and K2 were lower and those for R1 and R2 were higher in rat than in toad serum. The percentage fraction of occupied rat IGF binding sites was 3.6%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Serum sex hormone-binding globulin and serum nonsex hormone-binding globulin-bound testosterone fractions in prepubertal boys with chronic renal failure.

We had previously reported that serum sex hormone binding-globulin (SHBG) decreases and serum non-SHBG-bound testosterone (T) and free T increase significantly from infancy to late prepuberty in normal prepubertal children of both sexes. We had also shown an age-related delay in these changes in hypopituitary boys, which was reversed by GH treatment. Stunted growth and delayed puberty are conspicuous features of chronic renal failure (CRF). As another model of delay of growth and development, serum SHBG and serum T fractions were determined in 13 boys with CRF on chronic dialysis. In CRF, mean serum SHBG was significantly higher (99.1 +/- 68.9 nmol/L; P less than 0.05) than in 31 control (C) children of similar ages (66.2 +/- 34.9 nmol/L), while serum non-SHBG-bound T and free T were significantly lower (0.16 +/- 0.12 in CRF vs. 0.24 +/- 0.12 in C and 0.010 +/- 0.005 in CRF vs. 0.016 +/- 0.01 in C, respectively). On the other hand, serum total T (1.31 +/- 0.88 in CRF vs. 1.08 +/- 0.56 in C) and serum insulin-like growth factor-I (IGF-I; 1.06 +/- 0.74 in CRF vs. 1.35 +/- 1.70 in C) were not significantly different. A significant negative correlation between serum SHBG and chronological age as well as a significant positive correlation between serum non-SHBG-bound T and chronological age were found. For a given age, serum SHBG was higher, while serum non-SHBG-bound T was lower in patients with CRF (by analysis of covariance, P less than 0.01). It is postulated that, as has been proposed for hypopituitary boys, this delayed increment in serum T fractions could be responsible for the delay in the onset of puberty reported in CRF. It is known that GH decreases serum SHBG, acting on hepatic cells either directly or through the action of IGF-I. Since it has been suggested that patients with CRF have peripheral resistance to GH or IGF-I, the high levels of SHBG that we have detected in prepubertal boys with CRF could be taken as an additional evidence of this biological resistance.

Adolescent↗
PubMed1987

Growth in Turner's syndrome: long term treatment with low dose ethinyl estradiol.

The growth response to 100 ng/kg BW X day ethinyl estradiol (2-4 micrograms/day) given for 18 months was studied in a group of nine patients with Turner's syndrome, aged 8.6-13.3 yr. All patients were prepubertal and had elevated gonadotropin levels. Growth velocity increased from 3.09 +/- 1.05 (+/-SD) to 7.09 +/- 1.47 cm/yr in the first 6 months, 6.08 +/- 1.78 cm/yr in the second 6 months, and 4.03 +/- 1.65 cm/yr in the third 6 months. Bone age increased a mean of 0.82 +/- 0.34, 0.89 +/- 0.79, and 0.74 +/- 0.59 yr, respectively, in the three 6-month periods. Predicted height prognosis did not change after any period. All patients had pubertal changes, limited in most to slight breast development. Mean diurnal spontaneous GH secretion did not change during treatment. Plasma somatomedin-C levels were low before treatment, and ethinyl estradiol did not significantly increase somatomedin-C values. Our data confirm the ability of a low dose of ethinyl estradiol to increase growth velocity in girls with Turner's syndrome, although the effect diminished with time, and the excess bone age advancement precluded improvement of predicted height.

Adolescent↗
PubMed1976

Catecholamines released from cerebral cortex in the cat; decrease during sensory stimulation.

In an attempt to determine the functional role of catecholamine (CA) nerve terminals in cerebral cortex the release of endogenous norepinephrine (NE) and dopamine (DA) into superfusates from visual and somatosensory cortex of the cat have been measured by a sensitive radiometric enzymatic assay based on the methylation of CA by catechol-O-methyltransferase (COMT) in the presence of a [3H]-methyl donor and followed by resolution of 3H derivatives through a series of organic extractions. In the flaxedilized animal maintained under local anaesthesia with artificial respiration the concentration of CA measured in 30-min superfusates was fairly constant in a given experiment under basal conditions without sensory stimulation, but varied widely from one experiment to another. Variations in NE were often independent of those for DA. For visual cortex the average basal release of NE in experiments was 20.09 +/- 3.64 pg/min/sq.cm while the average for DA was 34.01 +/- 7.62 pg/min/sq.cm. In all experiments intermittent visual stimulation (15/sec) produced a significant reduction in release rate averaging about 42% for NE and 64% for DA in visual cortex. The reduction was relatively non-specific since visual or somatic sensory stimulation produced a decrease in release from both visual and somatic sensory cortical areas. Since it has been shown that there is a relatively non-specific increase in acetylcholine (ACh) release from sensory cortex during stimulation, it is proposed that ACh may regulate CA release at presynaptic CA terminals in the cortex as it does in the periphery. A marked increase in CA release observed on perfusing with nicotine or atropine is consistent with this hypothesis.

Acetylcholine↗