Brain-derived neurotrophic factor prevents the endothelial barrier dysfunction induced by interleukin-1ß and tumor necrosis factor-α.

BACKGROUND AND OBJECTIVE: Brain-derived neurotrophic factor (BDNF) promotes the regeneration of periodontal tissue. Although a local inflammatory step is required to initiate the subsequent process of tissue regeneration, excessive inflammation may inhibit or delay tissue regeneration. Therefore, the regulation of inflammation is essential for periodontal tissue regeneration. In the present study, we examined the influence of BDNF on the human microvascular endothelial cell (HMVEC) barrier dysfunction induced by interleukin (IL)-1ß or tumor necrosis factor (TNF)-α to determine the effects of BDNF on the regulation of local inflammation in periodontal tissue regeneration. MATERIAL AND METHODS: Endothelial permeability was analyzed using a Dextran transport assay with transwell plates. The expression of vascular endothelial (VE)-cadherin was assessed by immunoblotting and immunofluorescence microscopy. RESULTS: BDNF (25 ng/mL) inhibited increase induced in endothelial permeability by IL-1ß and TNF-α. IL-1ß and TNF-α decreased VE-cadherin protein levels, while BDNF recovered the reduction in HMVECs. BDNF protected the increase induced in endothelial permeability by IL-1ß and TNF-α through TrkB. The single addition of BDNF into the culture increased the expression of VE-cadherin in HMVECs. CONCLUSION: BDNF played an important role in inhibiting endothelial barrier dysfunction, which suggests that it may assist in enhancing periodontal tissue regeneration.

Placental norepinephrine transporter development in the ovine fetus.

The placenta has been shown to be a site of expression of several of the monoamine membrane uptake transporters. However, the development and relative contribution of transport-dependent mechanisms to placental catecholamine clearance in vivo have not been demonstrated. These studies were designed to determine the development of the placental norepinephrine transporter (NET) and the relative contribution of transport dependent mechanisms to whole body and placental catecholamine clearance. Norepinephrine clearance and production rate were determined in 122 +/- 1 day gestation chronically catheterized fetal sheep. Placental clearance was shown to account for over 40 per cent of total intrauterine clearance and, of the clearance in the placenta, nearly 50 per cent was uptake, transport-dependent as shown by specific pharmacologic blockade. NET transport expression was examined by measurement nisoxetine binding in placenta and compared with binding in the frontal cortex of fetal, newborn and adult animals. Nisoxetine is a selective ligand for the norepinephrine transporter. Nisoxetine binding was 20-fold greater in placenta than in frontal cortex. Placental transporter binding decreased modestly in between 99 days gestation and term (145 days) but did not change in frontal cortex. These results suggest that expression of the norepinephrine transporter in the placenta is associated with a significant capacity for neurotransmitter re-uptake in utero. Given the high fetal norepinephrine production rate, this capacity is important for fetal homeostasis. This site of transporter expression may be important in the pathogenesis of derangements in catecholamine production in the fetus and in the adverse effects on the fetus of drugs, such as cocaine, which block catecholamine re-uptake.

Human placental norepinephrine transporter mRNA: expression and correlation with fetal condition at birth.

The purpose of this study was to determine the primary form of human placental norepinephrine transporter (hNET) mRNA expressed in the human placenta and to compare the level of expression in normal pregnancies and in pregnancies complicated by drug exposure or other forms of physiological derangement. We used the hNET cDNA to measure RNA extracted from placenta and examined placental RNA following complicated and uncomplicated pregnancies. To compare transporter expression and its relation to fetal condition at birth, umbilical arterial plasma catecholamine levels, umbilical arterial blood gases and placental transporter mRNA level were compared by linear regression analysis. Uncomplicated pregnancies had a higher level of placental norepinephrine transporter mRNA than complicated pregnancies. An inverse relationship between umbilical cord norepinephrine level and transporter expression was demonstrated. We conclude that placental transporter expression represents an important and newly described metabolic function of the placenta. Placental catecholamine clearance mediated via the placental NET may be important in the pathophysiology of disorders associated with placental dysfunction, impaired placental blood flow or intrauterine growth retardation. This may also explain the adverse effects of drugs, such as cocaine, which block catecholamine transport.

Binding of [3H]triamcinolone acetonide to glucocorticoid receptors in brain cytosol fractions of rats with intact adrenals.

Binding of [3H]triamcinolone acetonide (TA) increased with prolongation of incubation periods of up to 5 h after the onset of incubation at 2 degrees C, with a plateau thereafter persisting for at least up to 48 h in brain cytosol fractions of rats with intact adrenals. Elevation of incubation temperature to 30 degrees C resulted in a marked reduction of the binding at equilibrium which persisted for only 1 to 2 h with complete abolition thereafter. The addition of sodium molybdate was effective in doubling the maximal value at 30 degrees C without markedly affecting the binding at 2 degrees C. [3H]TA binding at equilibrium determined at 2 degrees C was a reversible, saturable and structure selective process with uneven distribution profiles in rat brain. Among a variety of steroid hormones tested, TA was the most potent displacer with progressively less potent displacement by dexamethasone, deoxycorticosterone, progesterone, prednisolone, hydrocortisone and corticosterone. Among discrete brain regions examined, the highest density was detected in the cerebellum followed by the hippocampus, cerebral cortex, midbrain, striatum, hypothalamus and medulla-pons in a rank order of decreasing density. In contrast, both the cerebellum and medulla-pons had significantly higher affinities for [3H]TA than the cerebral cortex. Moreover, the binding was markedly inhibited by Zn2+ ions at 10 microM due to a decrease in the affinity. These results suggest that [3H]TA labels a ligand recognition domain on the cytoplastic glucocorticoid receptor complex with different affinities in rat brain.

Regulation of beta 1-adrenoceptors by glucocorticoids and thyroid hormones in fetal sheep.

The effects of betamethasone alone or in combination with thyroxine (T4) on ovine fetal beta-adrenoceptors were investigated at the molecular level. Ovine fetuses (126 days gestation; term = 150 days) were treated with a single ultrasound-guided intramuscular injection of 0.5 mg/kg betamethasone, betamethasone + 50 micrograms/kg T4, or saline. Forty-eight h after injection, lambs were delivered by cesarean section and evaluated three h for postnatal adaptation. Myocardial beta-adrenoceptor equilibrium dissociation constant (Kd) and maximal receptor density (Bmax), as assessed by [3H]dihydroalprenolol binding, were not significantly different in drug-treated groups compared to the control group. Northern hybridization and RNase protection assays of myocardial total RNA probed with a sheep beta 1-adrenoceptor riboprobe confirmed no changes in expression at the level of the gene. Levels of beta 1-adrenoceptor mRNA in the lung and brain were also unaffected by the treatments. Because other genes are responsive to glucocorticoids and thyroid hormones at this stage, the absence of up-regulation of beta-adrenoceptor number and steady-state levels of mRNA coding for beta 1-adrenoceptor following fetal corticosteroid and thyroid hormone treatment may indicate a specific, developmentally regulated repressor mechanism.

Ovine fetal-placental cocaine pharmacokinetics during continuous cocaine infusion.

OBJECTIVE: To investigate fetal-placental cocaine clearance, and to determine the fetal catecholamine and cardiovascular responses to continuous intravenous cocaine infusion in fetal sheep. METHODS: Eleven pregnant ewes and their fetuses (127 +/- 2 days' gestation; term 150 days) were chronically instrumented. Fetuses received intravenous cocaine at 0.05, 0.1, or 0.2 mg/kg/minute. Fetal cardiovascular and hematologic measurements were made before and serially for 90 minutes after initiation of the cocaine infusion. RESULTS: Steady-state fetal plasma cocaine concentrations were observed by 15 minutes of infusion and averaged 136 +/- 11, 318 +/- 65, and 610 +/- 36 ng/mL, respectively, at each dose. Fetal-placental cocaine clearance rate was independent of dose (337 +/- 39 mL/kg/minute), indicating that it is a first-order pharmacokinetic process. Fetal plasma concentration of benzoylecgonine, a principle cocaine metabolite, increased throughout the study to approximately 25% above cocaine levels by 90 minutes. There were significant increases in fetal heart rate (from 169 +/- 11 to 242 +/- 36 beats per minute), mean blood pressure (from 53 +/- 4 to 63 +/- 5 mmHg), and systolic blood pressure (from 68 +/- 2 to 80 +/- 5 mmHg), with a corresponding increase in catecholamine levels seen in the fetuses infused with 0.2 mg/kg/minute. These changes were not seen in the fetuses given lower doses of cocaine. CONCLUSION: Fetal-placental clearance of cocaine is a rapid, first-order pharmacokinetic process. During prolonged cocaine exposure, plasma benzoylecgonine concentrations accumulate significantly. Significant catecholamine and cardiovascular changes are seen in fetal sheep with a continuous infusion of cocaine at 0.2 mg/kg/minute or greater.

[Megaureters in adults].

Megaureters are common in children but are rarely found in adults, probably due to the scarcity of clinical symptoms. Reconstruction surgery in adults has been performed only exceptionally up to a few years ago. We encountered 7 adults with 7 megaureters in the recent 6 years. The underlying pathologic entities responsible for the megaureters were non-peristaltic lower segment, ectopic ureter and ureterovesical junction stenosis. Six adults with 6 megaureters were treated by complete surgical reconstruction and reimplantation of the ureter. The outcome of all the reported cases was excellent.

[Screening for prostatic diseases in one-day total health check-up by using prostate specific antigen, international prostate symptom score and QOL index].

We preliminarily studied screening for prostatic diseases in one-day total health check-up by employing prostate specific antigen (PSA), international prostate symptom score (IPSS) and quality of life (QOL) index. From January 6 to March 31, 1998, a total of 390 men were included in this study, whose age ranged from 50 to 78 years with the mean of 57.5 years. The questionnaires, IPSS and QOL index, were mailed to the participants in advance. PSA (IMx: Dainapack) was measured at the end of the health check-up and the results of tests were explained on the same day. Participants who showed more than 8 points in IPSS, more than 4 points in QOL index and/or more than 4.1 ng/ml in PSA were given a referral to urologists of corresponding hospitals for further examination. A total of 116 men (29.7%) were judged to need thorough examination. Among 106 men who were referred to urologists, only 34 (32.1%) had visited the urologists by the end of July 1998. Two men (0.51% in all participants) were diagnosed with prostate cancer, 10 received some pharmacotherapy, and 2 underwent transurethral resection of prostate. The results indicate that screening for prostatic diseases in total health check-up is useful, even in an institute without staff urologists, in close association with urologists.