Intravenous dexmedetomidine for cesarean delivery and its concentration in colostrum.

BACKGROUND: Dexmedetomidine is a sedative agent with high α2-adrenoreceptor selectivity. We investigated intravenous dexmedetomidine administration during scheduled cesarean delivery under neuraxial anesthesia; and its concentration in the colostrum. METHODS: Twenty-seven participants having elective cesarean delivery under combined spinal-epidural anesthesia were enrolled. After delivery and cord clamping, 6µg/kg/h of intravenous dexmedetomidine was administered for 10minutes, followed by a dose of 0.7µg/kg/h until peritoneal closure. Sedation, vital signs and side effects were recorded. Blood and colostrum samples were collected from each participant at 6, 12, and 24h after dexmedetomidine administration. Samples were analysed using liquid chromatography tandem-mass spectroscopy. RESULTS: Colostrum samples were collected from 10 patients. The median [95% CI] plasma dexmedetomidine concentration was 333 [303-534] pg/ml at 0h and 19.7 [13.5-25.8] pg/ml at 6h. The colostrum concentration was 12.3 [8.1-20.1] pg/ml at 6h. The dexmedetomidine completely disappeared from both within 24h. The calculated milk-to-plasma ratio at 6h was 0.76 [0.57-0.86]. The relative infant dose was 0.034% [0.020-0.062%]. At dexmedetomidine discontinuation, the Richmond Agitation-Sedation Scale score was -2 (range,-4 to -1). During surgery, no patients complained of nausea, peritoneal irritation or afterbirth pain. CONCLUSIONS: The dexmedetomidine milk-to-plasma ratio did not exceed 1 in any participant, and the relative infant dose was very low. Maternal sedation using dexmedetomidine is unlikely to be harmful for the infant.

Mechanism of action of 2,2'-(methylenediimino)bis-1,3,4-thiadiazole (NSC 143019), an antitumor agent.

The mechanism of action of 2,2'-(methylenediimino)bis-1,3,4-thiadiazole (NSC 143019) was clarified by studies on its effects on monolayer cultures of growing cells of the mouse cell line BALB/3T3. At concentrations below 50 muM, NSC 143019 specifically inhibited DNA and RNA syntheses without appreciably affecting protein synthesis. The syntheses of DNA and RNA were inhibited equally and concomitantly by the compound. The inhibition was reversed by removal of the compound and was prevented competitively by an equimolar amount of nicotinamide. It was also reversed completely by guanosine (0.1 mM) or deoxyguanosine (0.1 mM) and was reversed partially by xanthosine (1 mM). Other nucleosides did not influence the inhibition. The inhibition of DNA synthesis by NSC 143019 was not due to inhibition of RNA synthesis, and vice-versa. NSC 143019 inhibited the conversion of [8-14C]hypoxanthine to acid-soluble and -insoluble guanine nucleotides but not to adenine nucleotides. It was strongly suggested from these results that at concentrations of NSC 143019 below 50 muM the primary action of this compound might be due to the inhibition of GMP biosynthesis at the step of conversion of IMP to xanthosine 5'-phosphate.

Therapeutic Effect of Sirolimus for Lymphangioleiomyomatosis Remaining in the Abdominopelvic Region After Lung Transplantation: A Case Report.

PURPOSE: Sirolimus (SRL) is used to treat pulmonary lymphangioleiomyomatosis (P-LAM). There is limited evidence that SRL has systemic efficacy for the patients with extrapulmonary lymphangioleiomyomatosis (E-LAM) remaining after lung transplantation (LT) for P-LAM. This report examines the efficacy of SRL treatment for the patient with E-LAM remaining after an LT for P-LAM. CASE SUMMARY: The course of the patient's recovery from an LT for P-LAM was complicated by lymphedema in the left femoral region that was caused by two E-LAM lesions remaining in the left pelvic cavity and in the retroperitoneal area. After the LT was performed, the patient started SRL treatment to reduce the E-LAM lesions. The daily SRL dose, selected based on the standard SRL dose for P-LAM, was initiated at 1 mg/d and was maintained at 2 mg/d. The remaining E-LAM lesions and lymphedema in the left femoral region improved in approximately 9 months after the LT with the administration of both SRL and the standard immunosuppressive therapy used by Okayama University Hospital, including tacrolimus, mycophenolate mofetil, and prednisolone. The SRL and tacrolimus trough concentrations in whole blood were maintained within the therapeutic window for the next 1.5 years after initiation of SRL treatment. The patient experienced no severe adverse events that required discontinuation of the SRL treatment during this time. CONCLUSION: The patients with remaining E-LAM lesions may receive SRL treatment to improve the quality of life after LT for P-LAM as effective therapy in cases where the patient's recovery is complicated by E-LAM lesions.

Rat prostatic growth factors: purification and characterization of high and low molecular weight epidermal growth factors from rat dorsolateral prostate.

Growth factors which possibly participate in androgen-induced proliferation of rat prostate epithelial cells have been purified and characterized. Four distinct forms of growth factor were found in the extract of rat dorsolateral prostate. One of the factors was a member of heparin-binding growth factor (HBGF) family judging from its high affinity for heparin-Sepharose. The other three factors were capable of competing with [125I]epidermal growth factor (EGF) for the cell surface receptor, and recognized by anti-rat EGF antiserum. These EGF-like factors (EGF1-EGF3) were purified by ion-exchange chromatography, gel filtration and reverse phase HPLC. EGF1 showed microheterogeneity on chromatographic and electrophoretic separation and N-terminal sequence analysis. EGF1 showed an average molecular weight of about 35,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. These results indicated that EGF1 was a mixture of high molecular weight forms of EGF. The molecular weights of EGF2 and EGF3 were similar to that of rat submaxillary gland EGF (Mr = 5400). The amino acid sequence of EGF2 was identical with that of rat EGF except for the N- and C-terminal amino acids: aspartic acid instead of asparagine was found at the N-terminal position and C-terminal arginine was missing in EGF2. Although the N-terminal sequence of EGF3 (1-19) was identical with that of EGF2, the two factors were completely separated by gel filtration indicating a difference in the C-terminal structure. EGF1, EGF2 and EGF3 but not HBGF stimulated proliferation of primary cultured rat dorsolateral prostate epithelial cells.

The novel compound TDN-345 induces synthesis/secretion of nerve growth factor in C6-10A glioma cells.

A novel compound, TDN-345, not bearing catechol moiety, induced NGF synthesis/secretion in C6-10A glioma cells. Both intracellular and extracellular nerve growth factor (NGF) protein levels increased within 3 h and reached a maximum around 12 h after the addition of TDN-345. The induction of NGF synthesis/secretion by TDN-345 occurred in a concentration-dependent manner, beginning with about 0.1 microM and reaching a maximum at 10 microM. The ED50 was 0.88 microM. The induction was accompanied by an increase in NGF mRNA but not beta-actin mRNA. In a time-course study, the NGF mRNA level was found to reach a maximum 2-3 h after the addition of TDN-345 and then to return to control levels. The induction occurred dose-dependently. The catecholaminergic compound epinephrine, which induces NGF synthesis/secretion, increased the intracellular cyclic AMP content by more than 1000-times at 10 microM. In contrast, TDN-345 did not cause such a prominent increase in cAMP even at 100 microM. These results indicate that TDN-345 induces NGF synthesis/secretion by increasing NGF mRNA expression, and the action of TDN-345 clearly differs from that of epinephrine, as it does not seem to involve cAMP as a second messenger. The results of the present study suggest the existence of a signal transduction pathway for NGF synthesis/secretion which is not mediated by cAMP.

Carrier-mediated processes in blood--brain barrier penetration and neural uptake of paraquat.

Due to the structural similarity to N-methyl-4-phenyl pyridinium (MPP(+)), paraquat might induce dopaminergic toxicity in the brain. However, its blood--brain barrier (BBB) penetration has not been well documented. We studied the manner of BBB penetration and neural cell uptake of paraquat using a brain microdialysis technique with HPLC/UV detection in rats. After subcutaneous administration, paraquat appeared dose-dependently in the dialysate. In contrast, MPP(+) could not penetrate the BBB in either control or paraquat pre-treated rats. These data indicated that the penetration of paraquat into the brain would be mediated by a specific carrier process, not resulting from the destruction of BBB function by paraquat itself or a paraquat radical. To examine whether paraquat was carried across the BBB by a certain amino acid transporter, L-valine or L-lysine was pre-administered as a co-substrate. The pre-treatment of L-valine, which is a high affinity substrate for the neutral amino acid transporter, markedly reduced the BBB penetration of paraquat. When paraquat was administered to the striatum through a microdialysis probe, a significant amount of paraquat was detected in the striatal cells after a sequential 180-min washout with Ringer's solution. This uptake was significantly inhibited by a low Na(+) condition, but not by treatment with putrescine, a potent uptake inhibitor of paraquat into lung tissue. These findings indicated that paraquat is possibly taken up into the brain by the neutral amino acid transport system, then transported into striatal, possibly neuronal, cells in a Na(+)-dependent manner.

Recombinant human basic fibroblast growth factor (rhbFGF) induces secretion of nerve growth factor (NGF) in cultured rat astroglial cells.

Recombinant human basic fibroblast growth factor (rhbFGF) was found to induce secretion of nerve growth factor (NGF) in cultured astrocytes from rat brain. The induction was concentration dependent; a maximum increase of 2-fold was observed at concentrations of 3-10 ng/ml or rhbFGF. When rhbFGF was added to the astrocytes, the induction occurred within 8 h and leveled off after 12 h. Antiserum against rhbFGF completely blocked the induction. Maximum induction occurred under serum-free culture conditions and in cultures with a high cell density. These results suggest that rhbFGF may exert a neurotrophic effect on the central nervous system through the induction of NGF secretion by astrocytes.

Nicotinamide-N-methyltransferase is higher in the lumbar cerebrospinal fluid of patients with Parkinson's disease.

Parkinson's disease (PD) may be initiated or precipitated by endogenous toxins with a structure similar to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in genetically-predisposed individuals. Nicotinamide N-methyltransferase (NNMT) catalyzes N-methylation of nicotinamide and other pyridines to form pyridinium ions. The protein amount of NNMT was measured in the lumbar cerebrospinal fluid of PD patients by immunoblot analysis using anti-human NNMT antibody. In younger (65 years old or younger) PD patients, the relative level of NNMT protein was significantly higher than that in younger controls. The NNMT protein was significantly affected by aging: the amount decreased along with aging in PD patients. These findings suggested that excess NNMT in the central nervous system might be implicated in the PD pathogenesis.

Autoradiographic distribution of pituitary adenylate cyclase activating polypeptide (PACAP) binding sites in the rat brain.

Distribution of pituitary adenylate cyclase activating polypeptide (PACAP) binding sites was investigated in the rat brain and pituitary gland by means of in vitro autoradiography. High densities of specific [125I]PACAP binding were observed in the anterior pituitary, hippocampus (CA1-4 and dentate gyrus) and in the superior colliculus. Moderate to high labeling was observed in the periaqueductal gray matter, substantia nigra pars compacta, and in the habenula. The hypothalamus, thalamus, ventral tegmental area (VTA), mammillary body and medial geniculate body were moderately labeled. The present results support possible actions of PACAP on the pituitary functions, and further suggest that PACAP is a neurotransmitter/neuromodulator in the central nervous system.

A study of the concentration of orally administered sparfloxacin found in exudates from suture wounds beneath occlusive dressings.

The concentration of orally administered sparfloxacin (SPFX), an antimicrobial agent, in exudates from the suture wounds beneath occlusive dressings has been measured. Twenty-one patients who received oral therapy with 100 mg of SPFX prior to surgery and 200 mg/day of SPFX after surgery were studied. During the operations, the suture wounds were covered by occlusive film. 48h post-operation, wound exudates under the dressings were drawn and measured using high performance liquid chromatography. SPFX values were 0.801+/-0.340 microg/ml (mean+/-SD). The results suggest that wound exudates beneath the occlusive dressing have concentrations of SPFX high enough to prevent infection in most cases when administered orally.

Inhibition of brain mitochondrial swelling by idebenone.

The effects of idebenone on the swelling of rat brain mitochondria were studied. When FeCl3 was added to a mitochondrial suspension, a pronounced mitochondrial swelling occurred accompanied by the production of lipid peroxide; the two phenomena were closely correlated (r = 0.96, p less than 0.01). Idebenone inhibited the mitochondrial swelling and lipid peroxidation in a concentration-dependent manner; the concentration giving 50% inhibition was 37 microM for swelling and 53 microM for lipid peroxidation. Metabolites of idebenone also inhibited the lipid peroxidation. These results suggest that idebenone stabilizes the mitochondrial membrane by inhibiting lipid peroxidation in brain mitochondria.

Inhibition of lipid peroxidation by idebenone in brain mitochondria in the presence of succinate.

Lipid peroxidation in brain mitochondria was induced by NADH in the presence of ADP and FeCl3. A novel quinone compound, idebenone, inhibited this peroxidation and the inhibition was markedly enhanced by succinate, a substrate of mitochondrial respiration. The concentration of succinate required to exert the maximal effect was 1.5 mM. The concentration of idebenone giving 50% inhibition (IC50) was 0.5 and 84 microM in the presence and absence of succinate, respectively, indicating that succinate enhances the inhibition by 170-fold. Moreover, the inhibitory effect of idebenone in the presence of succinate was abolished by adding thenoyltrifluoroacetate (TTFA), an inhibitor of complex II in the mitochondrial respiratory chain. These results indicate that idebenone is changed through complex II to its reduced form, which protects mitochondria against lipid peroxidation.

Inhibition of platelet aggregation by idebenone and the mechanism of the inhibition.

The inhibitory effect of 6-(10-hydroxydecyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone (idebenone) on platelet aggregation was studied in rat and human platelets in vitro, and the mechanism of inhibition was examined in rat platelets. Idebenone inhibited the aggregation induced by collagen and thrombin in washed platelets, and by arachidonate and ADP in platelet-rich plasma (PRP). The inhibition was more prominent in collagen- and arachidonate-induced aggregation. In collagen-induced aggregation of human platelets, idebenone was 8-fold more potent than aspirin. In addition, idebenone inhibited prostaglandin synthesis and thromboxane B2 production, and also increased the cyclic AMP content in platelets. However, the concentration of idebenone required to inhibit thromboxane B2 production was much lower than that required to increase cyclic AMP. These results indicate that idebenone inhibits platelet aggregation by inhibiting thromboxane B2 synthesis rather than by increasing cyclic AMP content.

Effects of idebenone on lipid peroxidation and hemolysis in erythrocytes of stroke-prone spontaneously hypertensive rats.

Stroke-prone spontaneously hypertensive rats (SHRSP) were kept on a 1% NaCl solution as drinking water to shorten the onset-time of a stroke. The level of lipoperoxide (LPO) in the erythrocytes of SHRSP loaded with salt for 22 days was significantly higher than that of the controls. Idebenone treatment (30 mg/kg per day, p.o.) markedly decreased the LPO to the level of the controls. Hemolysis in SHRSP was accelerated by the salt-loading. Idebenone significantly inhibited the hemolysis in a dose-dependent manner. These results suggest that idebenone inhibits lipid peroxidation in erythrocytes and stabilizes the erythrocyte membrane.

Effects of idebenone on neurological deficits, local cerebral blood flow, and energy metabolism in rats with experimental cerebral ischemia.

Improvement of energy metabolism in ischemic cerebral tissue benefits the therapy of occlusive cerebrovascular disorders. In the present study, the effects of 6-(10-hydroxydecyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone (idebenone) on neurological signs, such as ischemic seizures, lactate and ATP contents of the cerebral cortex, and local cerebral blood flow, were assessed in stroke-prone spontaneously hypertensive rats (SHRSP) with experimentally induced cerebral ischemia. Experimental cerebral ischemia was caused by bilateral carotid artery occlusion (BCAO) in male SHRSP (8-10 weeks old). Pretreatment with idebenone (10-100 mg/kg, p.o.) for 3 or 10 days delayed the onset of ischemic seizure (acute stroke) and prolonged survival time in SHRSP roughly in a dose-dependent manner. When the compound (100 mg/kg, i.p.) was given once 30 min after BCAO, it exerted similar ameliorating effects on the neurological deficits. When idebenone (100 mg/kg for 3 days) was given orally, it did not significantly inhibit the decrease in regional cerebral blood flow induced by BCAO. However, the same treatment markedly inhibited increases in the lactate content and lactate/pyruvate ratio and the decrease in ATP content of the cerebral cortex. The compound did not affect cerebral blood flow in normal rats. These results suggest that idebenone ameliorates the neurological deficits related to cerebral ischemia, and that this effect is mediated by improving cerebral energy metabolism.

[Effect of idebenone and various nootropic drugs on lipid peroxidation in rat brain homogenate in the presence of succinate].

The effects of idebenone and various nootropic drugs on lipid peroxidation in rat brain homogenate were examined. Idebenone inhibited lipoperoxide (LPO) production in brain homogenate in a concentration-dependent manner, with an IC50 of 38 microM. The inhibition was strongly enhanced (about 100-fold) by adding succinate, a substrate in the mitochondrial respiration. The optimal concentration of succinate was 0.5 mM. Inhibition of lipid peroxidation in brain homogenate by various nootropic drugs in the presence or absence of succinate was then examined. Drugs added to the brain homogenate at 100 microM in the absence of succinate inhibited LPO production in the order: idebenone greater than vinpocetine greater than bifemelane greater than indeloxazine greater than calcium hopantenate. However, when the drugs were added at 1 microM in the presence of succinate, only idebenone demonstrated inhibition. These results suggest that although almost all of the drugs tested inhibit lipid peroxidation in brain homogenate, only idebenone is activated by succinate, the other drugs being insensitive to this compound.

Inhibition of lipid peroxidation by a novel compound (CV-2619) in brain mitochondria and mode of action of the inhibition.

Lipid peroxidation in rat brain mitochondria was induced by NADH in the presence of ADP and FeCl3. CV-2619 inhibited the lipid peroxidation in a concentration-dependent manner; the concentration giving 50% inhibition (IC50) was 84 microM. In addition, the inhibitory effect of CV-2619 was strongly enhanced by adding substrates of mitochondrial respiration; when succinate, glutamate, or succinate plus glutamate was added, the IC50 of CV-2619 was changed to 1.1, 10, or 0.5 microM, respectively. Metabolites of CV-2619 also inhibited the lipid peroxidation. The inhibitory effect of CV-2619 on mitochondrial lipid peroxidation disappeared when TTFA, an inhibitor of complex II in mitochondrial respiratory chain, was added. The results indicate that in mitochondria CV-2619 is changed to its reduced form which inhibits lipid peroxidation.

Antihypertensive effect of CV-4093.2HCl, a new calcium antagonist, in three rat models of hypertension.

The hypotensive action of CV-4093.2HCl (CV-4093), a new calcium antagonist, was studied in spontaneously hypertensive, renal hypertensive, DOCA-salt hypertensive and normotensive rats. CV-4093 (3 and 10 mg/kg, p.o.) dose-dependently decreased systolic blood pressure in the three types of hypertensive rats. At the dose of 10 mg/kg, the compound decreased the blood pressure to the normotensive level between 1 and 3 hr after it was administered; the antihypertensive effect lasted for at least 8 hr. The systolic blood pressure in normotensive rats was also decreased at 3 and 10 mg/kg, p.o., but less evidently than in the hypertensive rats. When the antihypertensive effect of CV-4093 was compared with that of seven known calcium antagonists in spontaneously hypertensive rats, it was the most potent and the most long-lasting.