Fcgamma receptor polymorphisms and periodontal status: a prospective follow-up study

AIMS

The aims of this study were to assess: (i) the distribution of Fcgamma receptor polymorphisms among patients with chronic periodontitis ("cases") and control subjects with no/minimal loss of periodontal tissue support in a Caucasian population; (ii) whether these polymorphisms can serve as severity markers for periodontitis; and (iii) whether they have any bearing on the response to periodontal therapy.

METHODS

The study sample consisted of 132 cases and 73 controls of comparable age and gender. Full-mouth periodontal status was assessed. Subgingival plaque (PL) samples and blood samples were obtained and analysed with respect to 19 bacterial species and homologous serum immunoglobulin G titres. Polymorphisms in the Fcgamma receptor IIa (131R/H) and IIIb (NA1/NA2) were assessed by polymerase chain reaction. Patients underwent periodontal therapy and were followed up at 4 and 30 months.

RESULTS

Neither polymorphism showed a skewed distribution among cases and controls. At baseline, periodontitis patients with Fcgamma RIIa-H/H131 genotype had more PL and deeper pockets than patients in other genotype groups (p < 0.05). Both bacterial levels and antibody titres were unrelated to genotype. The longitudinal analysis failed to detect an association between genotype and response to periodontal therapy.

CONCLUSIONS

The present data failed to demonstrate a clinically relevant relationship between the Fcgamma receptor IIa (131R/H) or IIIb (NA1/NA2) polymorphism and periodontal status.

A multicenter, phase II trial of weekly irinotecan (CPT-11) in patients with previously treated colorectal carcinoma

BACKGROUND

This multicenter, Phase II trial was performed to evaluate the antitumor activity and toxicity of irinotecan (CPT-11) in patients with metastatic colorectal carcinoma that had recurred or progressed after 5-fluorouracil (5-FU)-based chemotherapy.

METHODS

CPT-11 was given as a 90-minute intravenous infusion in repeated 6-week (42-day) courses comprising weekly treatment for 4 consecutive weeks followed by a 2-week rest. Tumor measurements were obtained after every second course of therapy. Toxicity was assessed weekly using the National Cancer Institute Common Toxicity Criteria.

RESULTS

A total of 166 patients were entered into the trial. The first 64 patients received a starting dose of 125 mg/m2. An additional 102 patients were enrolled at a starting dose of 100 mg/m2 to determine whether a reduction in the starting dose would result in lower toxicity without sacrificing efficacy. Objective responses to CPT-11 were observed in 18 patients (1 complete response and 17 partial responses) (response rate [RR] = 10.8%; 95% confidence interval [CI], 6.1-15.6%). An additional 67 patients (40.4%) had stable disease as their best response. At the 125 mg/m2 starting dose, the RR was 14.1% (9 of 64 patients; 95% CI, 5.5-22.6%). Among patients given a starting dose of 100 mg/m2, the RR was 8.8% (9 of 102 patients; 95% CI, 3.3-14.3%). The overall median survival was 9.9 months (range, 0.3-36.8 months). The most frequently observed Grade 3/4 toxicities were gastrointestinal events (i.e., diarrhea [27.1%], nausea [15.1%], emesis [9.6%], abdominal cramping [22.2%], and neutropenia [19.9%]). There were no significant differences in the frequencies of Grade 3/4 toxicities between the 125 mg/m2 and 100 mg/m2 starting dose levels except for Grade 3/4 emesis (21.9% vs. 2%; P < 0.001). Patients age > or = 65 years were twice as likely (38.6% vs. 18.8%; P < 0.008) to develop Grade 3/4 diarrhea compared with younger patients when all courses of therapy were evaluated. However, older age did not significantly predict for a higher incidence of first-course diarrhea (25.0% vs. 14.7%; P = 0.106).

CONCLUSIONS

CPT-11 can induce tumor regression in patients with metastatic colorectal carcinoma that has progressed during or shortly after 5-FU-based chemotherapy. Gastrointestinal events and neutropenia were the most common serious toxicities. Given the trend toward a higher response rate without substantially greater toxicity, 125 mg/m2 has been selected as the preferred starting dose for further studies. Careful attention to appropriate CPT-11 dose modification and early intervention with loperamide may be especially important in elderly patients.

Procoagulant activity of reversibly acylated human factor Xa

The plasma clotting factors used to treat hemophiliacs who have developed inhibitory antibodies have a shared history of limited clinical safety and utility. To improve on existing bypass factors, we have developed a reversibly acylated form of human plasma factor Xa capable of providing a time-dependent release of procoagulant activity. Factor Xa was treated with p-amidinophenyl p'-anisate to generate anisoyl Xa. The chemical modification of the protein involves acylation of the active site serine residue of factor Xa. Anisoyl Xa deacylated in a time, pH, and temperature-dependent manner. Active factor Xa generated on deacylation of anisoyl Xa exhibited amidolytic and prothrombinase complex activities in in vitro assays, the level being comparable to those of untreated factor Xa. When Anisoyl Xa was infused into rabbits, active factor Xa was generated on deacylation of the acylated enzyme, which shortened the activated partial thromboplastin time (APTT) in a dose-dependent manner. The duration of effect on rabbit APTT could be directly correlated to the level of human plasma factor Xa. Because anisoyl Xa bypasses the "tenase" complex that is compromised in hemophilia A and B and is unaffected by inhibitory antibodies, it has the potential to be used as an effective bypass therapy.

Effect of gamma carboxylation on prothrombinase inhibitory activity of catalytically inactive factor XA

Recombinant catalytically inactive factor Xa (factor rXai) is capable of assembly into inactive prothrombinase complexes, thus serving as a competitive inhibitor (Ki = 0.3nM) of active factor Xa. In order to study the role of gamma carboxylation in prothrombinase complex assembly, we have prepared differentially gamma carboxylated factor rXai and have measured the activities of these proteins in prothrombinase complex inhibition and in extension of plasma clotting. A factor rXai preparation containing 8 out of a possible maximum of 11 g carboxyglutamic acid (GLA) residues was found to be as active as chemically inactivated plasma factor Xa which was fully gamma carboxylated. Loss of a single additional g carboxyglutamic acid in the recombinant protein, however lead to a marked loss in activity. Factor rXai preparation with 8 GLA residues is also detected by a monoclonal antibody specific for a GLA dependent epitope. Thus assembly of the factor Va/Xa complex on phospholipid membranes does not require the presence of all of the g carboxyglutamic acid residues present in the plasma protein.

Dose-related haemodynamic effects and pharmacokinetics of oral nicorandil in patients evaluated for chest pain

We studied the acute haemodynamic dose response of nicorandil, a combined nitrate and potassium channel opener, in patients evaluated for chest pain. Single dose oral nicorandil (5, 10, 20, or 30 mg) or placebo was given to 42 right-heart catheterized patients using a randomized block design. Persistent, significant (P < 0.05) haemodynamic changes occurred primarily after 30 mg. Arterial systolic pressure fell significantly after all doses and remained reduced (maximum, 31 mmHg) up to 6 h after 30 mg; heart rate increased significantly up to 1 h. Individual haemodynamic sensitivity varied and three patients (1, 10 mg; 2, 30 mg) developed transient symptomatic hypotension associated with bradycardia. Pulmonary artery systolic pressure (diastolic was unchanged) declined significantly (maximum, 5 mmHg) up to 6 h after 30 mg whereas pulmonary capillary wedge (baseline normal) and mean right atrial pressures decreased transiently. Cardiac index (baseline normal) declined slightly (significantly after 30 mg); however, stroke volume index and stroke work index were significantly and persistently reduced after all doses. Total systemic vascular resistance declined slightly after 30 mg. Individual plasma nicorandil concentrations were variable and systemic bioavailability was reduced compared with values reported in healthy subjects. Nicorandil demonstrated cardiac unloading actions. Variable plasma concentrations, haemodynamic effects, and patient sensitivity warrant low initial doses with individual dose titration, especially if cardiac filling pressures are low.

Acute effects of increasing doses of nicorandil on renal function in man

The effects of nicorandil, a nicotinamide derived vasodilator combining nitrate and potassium channel opener actions, on kidney function have not been determined. This study investigated changes in renal blood flow and glomerular filtration rate as estimated using simultaneous 131I-iodohippurate and 125I-iothalamate plasma clearances. Forty-two healthy subjects in sodium balance received placebo and 2.5 mg (n = 8), 5 mg (n = 9), 10 mg (n = 8), 20 mg (n = 8) or 30 mg (n = 9) nicorandil orally. Peak nicorandil plasma concentrations occurred in the first hour. Nicorandil produced dose related decreases in blood pressure with maximum reductions (mean +/- standard error of the mean) after 30 mg of -6 +/- 1 mmHg systolic and -8 +/- 2 mmHg diastolic. Renal blood flow averaged 655 +/- 28 ml/minute/1.73 m2 after placebo. Renal blood flow changed 10 +/- 11% after 2.5 mg, -6 +/- 8% after 5 mg, -12 +/- 11% after 10 mg, -11 +/- 5% after 20 mg, and 8 +/- 6% after 30 mg, however, these changes did not reach statistical significance. Glomerular filtration rate averaged 113 +/- 3 ml/minute/1.73 m2 and was unaltered after nicorandil. Nicorandil had no effect on filtration fraction but fractional excretion of sodium tended to decrease with dose. These dose-related effects of nicorandil are consistent with other mixed vasodilators. At therapeutic doses, renal perfusion and function are preserved despite reductions in systemic blood pressure by nicorandil.

The anion-binding exosite is critical for the high affinity binding of thrombin to the human thrombin receptor

The thrombin receptor has been shown to be a novel member of the family of G-protein coupled receptors (Vu, T.-K. H., Hung, D.T., Wheaton, V.I., and Coughlin, S.R. (1991) Cell 64, 1057-1068). This receptor appears to be activated through a thrombin-mediated proteolytic mechanism which exposes a "tethered ligand" responsible for receptor activation. In order to investigate the initial interactions of thrombin with this receptor, we have constructed cell lines which express high levels of the human thrombin receptor and studied the binding of various forms of thrombin to the cell surface. Analysis of transfected cells with thrombin receptor monoclonal antibodies identified a particular cell line (clone #5-18) which displayed > 150,000 thrombin receptors per cell. Clone #5-18 appeared to express functional receptors since treatment with thrombin resulted in both a 15-20 fold increase of cytoplasmic phosphoinositide levels and a comparable shift in the EC50 of thrombin-mediated calcium mobilization when compared to non-transfected CHO cells. Binding of 125I-alpha-thrombin to clone #5-18 did not reach equilibrium at 37 degrees C. However, direct binding studies of 125I-alpha-, 125I-diisopropylphospho (DIP)-alpha-, and 125I-beta-thrombin to clone #5-18 demonstrated that binding at 4 degrees C was saturable and reversible for each ligand. Analysis of the binding data revealed Kd's of 0.8 nM, 0.7 nM and 9.7 nM for 125I-alpha-, 125I-DIP-alpha- and 125I-beta-thrombin respectively. Association of 125I-alpha-, DIP-alpha, and beta-thrombin could be competed by unlabelled alpha- and DIP-alpha-thrombin. Unlabelled beta-thrombin, which has a modified anion-binding exosite, was a poor competitor for 125I-alpha- and 125I-DIP-alpha-thrombin, but did compete for 125I-beta-thrombin. In addition, the hirudin54-65 peptide competed at submicromolar concentrations for the binding of alpha- and DIP-alpha-thrombin, but not for beta-thrombin. This peptide binds specifically at the anion-binding exosite of alpha-thrombin and has been shown to have a lower affinity for beta-thrombin. These results demonstrate directly a high affinity interaction between thrombin and its receptor, and suggest that an important component is the high affinity association of the thrombin receptor with the anion-binding exosite of thrombin.

The pharmacokinetics and haemodynamic effects of continuous nicorandil infusion in healthy volunteers

We have studied the pharmacokinetics and haemodynamic effects of nicorandil after a 12-h infusion. Nicorandil is a mixed vasodilator combining the actions of a nitrate and a potassium channel opener. Nicorandil was infused for 12 h in 21 healthy volunteers at rates of 0.05, 0.10, and 0.20 microgram.kg-1.min-1 using a placebo controlled, crossover design. Systemic blood pressure, heart rate, electrocardiographic (ECG) intervals, and cardiac output (impedance cardiography) were measured supine and standing. Dose-related, steady-state plasma nicorandil concentrations occurred within 3 to 4 h. Nicorandil's pharmacokinetics were linear with dose. Four 0.20 microgram.kg-1.min-1 nicorandil infusions were terminated early primarily because of moderate or severe headaches. There were no safety concerns (ECG intervals, laboratory assays). Blood pressure fell versus placebo only in the standing position and heart rate increased slightly (not significant). That is, standing blood pressure in the 6 to 12 h interval fell from baseline 8.0*/6.8, 1.6/5.1, and 9.8*/7.9* mmHg (systolic/diastolic, * = P < 0.05 versus placebo) at 0.05, 0.10, and 0.20 micrograms.kg-1.min-1 respectively. Cardiac output increased slightly above placebo at lower doses. Haemodynamic changes correlated poorly with plasma nicorandil concentrations. Similar total doses were less well-tolerated when extended over 12 h. We saw no evidence of pharmacodynamic tolerance to nicorandil within 12 h.

Mechanism of platelet-derived growth factor (PDGF) AA, AB, and BB binding to alpha and beta PDGF receptor

The biological effects of platelet-derived growth factor (PDGF) are mediated by cell surface alpha and beta PDGF receptors, which, as a result of ligand binding, undergo dimerization in a manner consistent with PDGF being bivalent. In order to directly demonstrate PDGF bivalency and to define the binding of PDGF AB to isolated beta receptor, we developed solid-phase binding assays using purified recombinant extracellular domain of human PDGF receptors. PDGF AA, AB, and BB were prepared from the monomeric chains expressed in Escherichia coli, and each was purified to homogeneity; PDGF AB contained < 0.5% of either homodimer. The interactions of these isoforms with immobilized PDGF receptors were examined by several approaches. Scatchard analysis revealed high affinity binding (Kd = 0.5-1.0 nM) of radiolabeled PDGF AA and AB to alpha receptor and of PDGF BB to both receptor subtypes. Contrary to previous reports, PDGF AB also bound beta receptor with high affinity (Kd = 0.9 nM). When a B-chain-specific monoclonal antibody that recognizes the putative binding domain of PDGF BB was used for ligand detection, we found that PDGF AB binding to beta receptor occurred exclusively through the B-chain subunit, whereas binding to alpha receptor occurred through either subunit. In addition, site-directed mutagenesis was used to specifically inactivate the B chain of PDGF AB, which eliminated binding to the beta receptor without affecting alpha receptor binding. These results establish that PDGF is bivalent and that monovalent ligand retains high affinity receptor binding.

Carbohydrate residues modulate the activation of coagulation factor X

Factor X is a plasma protein involved in both the intrinsic and extrinsic pathways of blood coagulation. Post-translational modifications of the protein involve gamma-carboxylation of specific glutamic acid residues, beta-hydroxylation of one aspartic acid residue, and N- and O-linked glycosylation. Even though it is known that gamma-carboxylation is instrumental in regulating biological activity, the role of glycosylation in the function and properties of factor X has not been previously investigated. We utilized lectin binding and glycosidase treatment to investigate the functional role of carbohydrates on the activation peptide of factor X. Sambucus nigra agglutinin, a lectin that binds to sialic acid terminally linked alpha(2-6) to galactose or N-acetyl-galactosamine inhibits activation of human factor X in a dose-dependent manner. Inhibition of activation was observed for both intrinsic (factor IXa/VIIIa) and extrinsic (factor VIIa/tissue factor) pathway complexes. In accordance with this, selective removal of sialic acid residues on the activation peptide of factor X by neuraminidase also results in a drastic reduction of activation of the zymogen by these complexes. Corresponding reduction of activity in classical clotting assays (activated partial thromboplastin time and prothrombin time) also agrees with this observation. These results suggest a possible role of N-linked carbohydrates in the activation of factor X.

Continuous intravenous dosing with ciprostene using a portable pump in ambulatory patients

Parenteral compounds present special drug delivery challenges. This open-label study evaluated a portable infusion pump as a means to deliver intravenous ciprostene, a stable prostacyclin analog. Ten patients with peripheral vascular disease and claudication received ciprostene (titrated to 120 ng/kg/min) infused over 8 hours 1 day per week for 4 consecutive weeks. Patients successfully maintained the pump strapped to the waist. The mean +/- standard deviation delivery error, with volumes of 6 to 10 mL over 8 hours, was -0.895 +/- 3.177%. Accordingly, the pump performed well with a potent drug under these clinical conditions. Headache, flushing, and infusion site irritation during infusion were the most frequent side effects. Blood pressure remained unchanged during infusion; however, heart rate increased significantly (P < .05, maximum increase was 13.9 +/- 2.1 beats per minute [mean +/- standard error of the mean]. Mean (+/- standard error of the mean) relative claudication times on treadmill remained unchanged; however, absolute claudication times increased (P < .05) from 6.6 +/- 1.8 to 10.0 +/- 2.2 minutes. Ciprostene inhibited adenosine diphosphate-induced platelet aggregation by 56.0 +/- 12.7% (mean +/- standard error of the mean). Mean template bleeding times and plasma concentrations of platelet-specific proteins (beta-thromboglobulin, platelet factor 4) did not change.

The haemodynamic effects and pharmacokinetics of intravenous nicorandil in healthy volunteers

We have studied the effects of intravenous nicorandil, a mixed arterial and venous vasodilator, in 48 healthy volunteers. Nicorandil (20, 28, 39, 54, 74, 103, 144, or 200 micrograms.kg-1) or placebo were given over 5 min to subjects supine (16 subjects, 2 doses) or sitting (32 subjects, 1 dose) in a single-blind crossover design. Electrocardiographic intervals, blood pressure, and heart rate were measured before and for 8 h after dosing. Blood and urine safety laboratory studies were also performed before and after dosing. All intravenous infusions of nicorandil and placebo were well tolerated and there were no clinically important safety concerns. The most frequent adverse event after nicorandil was headache (24 events by 19 subjects), although its occurrence was not strictly dose related. One subject experienced transient symptomatic hypotension (144 micrograms.kg-1). Mean plasma nicorandil concentrations were dose-related and fell with a half-life of 0.7 to 1.2 h. Systemic clearance and volume of distribution tended to decrease as dose increased. Sitting subjects showed marginally lower (< 20%) systemic clearances and larger values of Cmax and AUC. Nicorandil produced dose-related reductions in blood pressure, with consistent statistically significant differences from placebo after the 144 and 200 micrograms.kg-1 doses. The falls in blood pressure were greater for diastolic pressure and in this supine position. At 200 micrograms.kg-1, the mean falls in systolic/diastolic pressures (mm Hg) during the first hour were 10.9/14.7 supine and 6.1/9.1 sitting; systolic pressure returned to baseline after 8 h and diastolic pressure after 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

A novel monoclonal antibody dependent on domain 5 of the platelet-derived growth factor beta receptor inhibits ligand binding and receptor activation

Platelet derived growth factor (PDGF) induces activation of the protein tyrosine kinase domain of the PDGF receptor, resulting in receptor dimerization and the initiation of mitogenesis in responsive cells. In order to identify domains of the receptor involved in these processes, a panel of monoclonal antibodies (MAbs) against the extracellular region of the human PDGF receptor was developed and screened to identify which of these specifically block PDGF binding. One of these, MAb 2A1E2, binds PDGF beta receptor with high affinity and blocks PDGF BB binding in a whole cell binding assay with an IC 50 of 0.1 nM. Inhibition of binding results in the inhibition of ligand-induced receptor phosphorylation, dimerization and mitogenesis in cells expressing the PDGF beta receptor. MAb 2A1E2 has been mapped to the fifth Ig domain of the PDGF beta receptor, implying that this domain is important for ligand binding, dimerization and/or activation. The potency of MAb 2A1E2 for inhibiting PDGF BB binding indicates that this antibody is ideally suited to identify and characterize PDGF BB-induced biological responses.

Expression, purification, and characterization of inactive human coagulation factor Xa (Asn322Ala419)

We have expressed in Chinese hamster ovary cells a catalytically inactive form of human factor Xa (factor rXai). A recombinant precursor of human factor Xa was inactivated by two point mutations in the serine protease catalytic triad, Asp322Asn and Ser419Ala. A two-step purification to homogeneity of the secreted material involved immunoaffinity followed by heparin-agarose chromatography. Two forms were identified; a fully processed dimer (70%) and a partially processed monomer (30%). Limited N-terminal amino acid sequencing of factor rXai detected the predicted residues and gamma-carboxyglutamic acid content was 90% of human plasma control. Although devoid of measurable proteolytic activity, factor rXai competitively inhibited plasma factor Xa assembly into functional prothrombinase complexes (Ki = 3 x 10(-10) M). Factor rXai also inhibited plasma clotting in a dose-dependent manner. The possible use of recombinant catalytically inactive proteins as a general approach for pharmacological regulation of human diseases is discussed.

Clinical pharmacology of nicorandil in patients with congestive heart failure

Nicorandil is a nicotinamide derivative with a potential role in human therapeutics because of its potent vasodilating properties. The pharmacokinetics of oral nicorandil administration and the relationships between plasma nicorandil concentration and hemodynamic responses were examined in 25 patients with moderate to severe congestive heart failure. The dose range from 10 to 60 mg was studied. Elimination half-life for this dose range was substantially longer than that previously reported in normal volunteers. Total area under the curve increased in a curvilinear fashion with progressive dose increments, indicating a disproportionate increase in systemically available drug at higher doses. Hemodynamic responses generally correlated well with plasma nicorandil concentration, with rapid loss of cardiovascular activity corresponding to the efficient clearance of nicorandil.

Hemodynamic and neurohumoral responses to intravenous nicorandil in congestive heart failure in humans

Nicorandil is a vasodilator drug that combines potassium channel opening properties with nitrate effects. The resulting potent and unique vasodilating properties suggest a potential therapeutic role in congestive heart failure. We therefore studied the acute hemodynamic and neurohumoral responses to nicorandil, given as single intravenous bolus doses of 158, 251, 398, or 630 micrograms/kg, to 22 patients with chronic congestive heart failure (ejection fraction less than 40%). Hemodynamic responses occurred within 5 min of dosing and terminated within 240 min. The heart rate was significantly increased only at 5 min after the 158 micrograms/kg dose, and was unchanged after all other doses. The mean arterial pressure was reduced only by the 398 and 630 micrograms/kg doses. The pulmonary capillary wedge pressure and right atrial pressure were significantly reduced by all doses within the initial 30 min; this reduction in pulmonary capillary wedge pressure was better sustained over time by the two larger doses, whereas the reduction in right atrial pressure was sustained only by the 158 micrograms/kg dose. The cardiac index was reduced by the 158 micrograms/kg dose, but increased after 251, 398, and 630 micrograms/kg of nicorandil. Plasma nicorandil concentrations were positively correlated with changes in cardiac index, systemic arterial pressure, pulmonary capillary wedge pressure, heart rate, and systemic vascular resistance. When measured 1 h after dosing, plasma immunoreactive ANF decreased, norepinephrine concentrations did not change, and plasma renin activity increased, but only at the 630 micrograms/kg dose level.(ABSTRACT TRUNCATED AT 250 WORDS)

Design of constructs for the expression of biologically active recombinant human factors X and Xa. Kinetic analysis of the expressed proteins

Activation of vitamin K-dependent plasma proteases occurs by specific interaction with components of the blood coagulation cascade. In this report, we describe the direct expression and enzymatic characterization of the human coagulation zymogen factor X and its activated form, factor Xa, from transformed Chinese hamster ovary fibroblast cell lines. Expression was achieved using either a full-length factor X cDNA or a unique mutant factor Xa cDNA. The functional factor Xa precursor contained a novel tripeptide bridge in place of the native 52-amino acid activation peptide. This mutation allowed for intracellular processing and secretion of the activated form of factor X. Secreted recombinant factors X (rX) and Xa (rXa) were purified by sequential anion-exchange and immunoaffinity chromatography. The enzymatic activities of factors rX and rXa were compared with those of plasma factors X and Xa in three independent assay systems. In comparison to human plasma factor X, the amidolytic, prothrombinase complex, and plasma clotting activities of factor rX were 50, 85, and 43%, respectively. The corresponding comparative activities for factor rXa were 32, 64, and 48%, respectively. The ability to directly express mutant forms of biologically active human factor X will facilitate the structure/function analysis of this important blood coagulation protein and may lead to the development of novel coagulation inhibitors.

Hemodynamic effects of oral nicorandil in congestive heart failure

Twenty-five patients with congestive heart failure (CHF) underwent a double-blind randomized study of the acute hemodynamic effects of orally administered nicorandil, a newly developed vasodilator drug. A dose range of 10 to 60 mg was studied. Nicorandil, at a dose of 60 mg, caused statistically significant decreases in systemic systolic and diastolic blood pressure, right atrial pressure, pulmonary capillary wedge pressure, systemic and pulmonary vascular resistance and systolic and diastolic pulmonary arterial pressure. A brief increase in cardiac index attributable to an increase in stroke volume without a change in heart rate was also observed. A dose of 40 mg produced similar results in cardiac index and systemic and pulmonary vascular resistance, but changes in other hemodynamic parameters were much smaller in magnitude and usually not of statistical significance. No significant hemodynamic response was seen to doses of 10 and 20 mg of nicorandil. Duration of action was short with nearly all hemodynamic parameters returning close to baseline within 3 hours. This rapid decrease in activity occurred in concert with a rapid plasma clearance of nicorandil as determined by serial measurements of plasma drug concentration. This study suggests that first-dose orally administered nicorandil elicits favorable, but brief, hemodynamic effects in CHF at doses greater than or equal to 40 mg.

Cardiovascular depressant effects of the kappa opioid receptor agonists U50488H and spiradoline mesylate

The cardiovascular effects of the selective kappa opioid receptor agonists U50488H and spiradoline mesylate were examined in pentobarbital-anesthetized mongrel dogs and chloralose-anesthetized cats. In the dog studies, U50488H (0.01-3.0 mg/kg, i.v.) produced a dose-related depression in mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular dp/dt, and heart rate. These effects were completely reversed by a 1 mg/kg i.v. dose of the opioid receptor antagonist naloxone. A second kappa agonist, spiradoline mesylate, also produced a naloxone-reversible cardiovascular depression. Furthermore, the compound did not interfere with the positive inotropic or hypertensive effects of norepinephrine (1 microgram/kg, i.v.), showing that the cardiovascular depressant effects of the kappa agonist are unrelated to interference with alpha- or beta-adrenergic receptor mechanisms. In normal cats anesthetized with chloralose, which produces less depression of sympathetic tone than does pentobarbital, spiradoline mesylate did not decrease the MAP in i.v. doses up to 1.0 mg/kg. However, a dose-related increase in sympathetic nerve discharge (SND) was observed (+290% at 1.0 mg/kg). In contrast, in baroreceptor-denervated cats, spiradoline mesylate caused a dose-related hypotensive effect with no change in SND. These results show that the cardiovascular effects of the kappa agonists are peripherally mediated and that reflex sympathetic activity, if uncompromised, can produce a full compensation.

Female autonomy, the family, and industrialization in Java

It is generally argued that industrialization has an adverse affect on the position of women due to their exclusion from industrial employment and the resultant erosion of their status. This article addresses a case study to the question of gender stratification and industrialization by analyzing the relationship between factory daughters and their families in Java, Indonesia. The case study suggests that industrialization at the very least maintains, and may even enhance, female status within the family. I compare this Southeast Asian case with the East Asian experience to demonstrate the important role family systems play in mediating the effects of industrialization upon women and family change.

Beneficial effects of the kappa opioid receptor agonist U-50488H in experimental acute brain and spinal cord injury

The effects of the selective kappa opioid receptor agonist U-50488H (trans-3,4-dichloro-N-methyl-N[2-(pyrrolidinyl)-cyclohexyl]- benzeneacetamide) were examined in acute head and spinal injury models. First, in a blinded protocol, male CF-1 mice were treated intravenously with either saline or U-50488H (1, 3 or 10 mg/kg) within 3-5 min following a reproducible and quantifiable moderately severe (900 g/cm) concussive head injury. Using a grip test at 1 h postinjury to evaluate the neurological status of the injured mice, U-50488H produced a dose-related improvement in early recovery compared to the saline-treated mice. The effect was significant (P less than 0.05) after the 3 or 10 mg/kg i.v. doses. A similar concussive injury markedly reduced the % of cardiac output perfusing the forebrain (cerebral blood flow). U-50488H (10 and 20 mg/kg) partially reversed this effect to a significant degree 60 min after a 20 mg/kg dose. Secondly, the effects of U-50488H on the development of progressive post-traumatic spinal cord white matter ischemia after a 500 g/cm contusive injury were studied in pentobarbital-anesthetized cats. In 4 untreated cats, there was a progressive fall in spinal cord and blood flow (SCBF) from a 10-min postinjury level of 10.5 +/- 0.7 ml/100 g/min to 6.1 +/- 0.3 (P less than 0.03 by paired t at 4 h).(ABSTRACT TRUNCATED AT 250 WORDS)

Post-traumatic spinal cord ischemia: relationship to injury severity and physiological parameters

Alterations in lumbar spinal cord white matter blood flow (SCBF) during the initial 4 hours following contusion injury were examined in cats anesthetized with either dial-urethane or sodium pentobarbital and correlated with changes in cardiovascular parameters (MAP, HR), blood gases (pCO2, pO2), and pH. In the dial-urethane anesthetized cats, the effect of a severe 500 g-cm contusion on SCBF was determined at the center of the injury site vs. an adjacent site 3 mm away. At the injury site, SCBF fell progressively from a pre-injury mean of 13.9 +/- 0.8 (S.E.) mg/100 g/min to a 4 hour value of 7.0 +/- 1.3 (-49.6%). In contrast, SCBF in the adjacent white matter tissue was dramatically increased to 22.4 +/- 1.9 ml/100 g/min (+61.2% over pre-injury; p less than 0.025), at 10 min post-injury falling gradually back to only slightly below the pre-injury level at 4 hours. The severe contusion resulted in prolonged hypotension and bradycardia that was significant by 10 min post-injury while arterial blood gases and pH did not change over the experimental course. A very similar post-traumatic hypoperfusion was observed at the injury site in pentobarbital anesthetized animals in regard to the time course and extent of the decline in SCBF (-55.6% at 4 hours). Although the decrease in SCBF over time was gradual, the MAP and HR were maximally depressed by 10 min post-injury. A more moderate contusion (300 g-cm) resulted in an initial hyperemia followed by a return of SCBF to the pre-injury level by 30 min with no significant change thereafter even though the MAP was depressed to nearly the same extent as in the more severely injured cats. These results demonstrate that post-traumatic spinal cord ischemia is a phenomenon localized to the spinal injury site and directly related to the injury force with moderate injury actually causing a temporary hyperemia. In addition, a significant difference in SCBF may exist between the injury site and adjacent spinal tissue only a few mm away. No correlation between the increase or decrease in SCBF and change in cardiovascular parameters or blood gases following injury is demonstrable nor does anesthetic choice seem to make a significant difference. Thus, post-traumatic changes in SCBF appear to be due to the elaboration of local mediators for the most part unrelated to concomitant alterations in spinal cord perfusion pressure.

A pharmacological analysis of the pathophysiological mechanisms of posttraumatic spinal cord ischemia

A pharmacological analysis was carried out to determine the possible role of aberrant calcium fluxes, vasoactive arachidonic acid metabolites, and microvascular lipid peroxidation in the development of posttraumatic spinal cord white matter ischemia. Pentobarbital-anesthetized cats were treated intravenously 30 minutes before a 500-gm-cm contusion injury to the lumbar spinal cord with one of the following test drugs: the Ca++ channel antagonists verapamil, diltiazem, or nifedipine; the cyclo-oxygenase inhibitors ibuprofen or meclofenamate; the thromboxane A2 (TXA2) synthetase inhibitor furegrelate sodium; or the stable epoprostenol (prostacyclin, or PGI2) analogue ciprostene calcium alone or in combination with furegrelate sodium. Another group of animals was pretreated for 5 days before spinal injury with a combination of the antioxidants vitamin E and selenium in high doses. The hydrogen clearance technique was used to make repeated measurements of spinal cord blood flow (SCBF) in the dorsolateral funiculus of the injured segment before and for 4 hours after injury. In 11 untreated uninjured cats, the mean preinjury SCBF was 12.7 +/- 1.5 ml/100 gm/min. Following contusion, there was a progressive decline in SCBF to 6.8 +/- 0.4 ml/100 gm/min, or 53.5% of the preinjury level at 4 hours. In comparison, the Ca++ antagonists diltiazem and nifedipine (but not verapamil) prevented a significant posttraumatic decrease in SCBF. Similarly, both cyclo-oxygenase inhibitors (ibuprofen and meclofenamate) maintained SCBF within normal limits (10 ml/100 gm/min or greater). However, neither TXA2 synthetase inhibition nor the stable PGI2 analogue alone had a significant effect in preventing ischemia, whereas a combination of the two agents did serve to support SCBF. The most impressive preservation of posttraumatic SCBF, however, was observed in the antioxidant-treated animals. Based upon these results, a hypothesis is presented concerning the pathogenesis of posttraumatic central nervous system ischemia which integrates an injury-induced rise in intracellular Ca++, the increased synthesis of vasoactive prostanoids (such as prostaglandin F2 alpha and TXA2), and progressive microvascular lipid peroxidation.

Suloctidil treatment prevents the development of post-traumatic feline spinal cord ischemia

The effects of suloctidil (1.0 mg/kg i.v.) on white matter spinal cord blood flow (SCBF) and somatosensory evoked potential (SEP) conduction were assessed in a feline lumbar spinal cord contusion model. SEP conduction ceased immediately after a 500 g-cm injury and did not recover. SCBF following suloctidil declined by only 12% from pre-injury levels over the 4 hr experiment as compared to a 42% decline observed following vehicle injection. Accordingly, 7/8 vehicle cats, but only 1/5 suloctidil-treated cats, had 4 hr SCBF values of less than 10 ml/100 g/min. Bradycardiac and hypotensive effects of suloctidil were also noted. The ability of suloctidil to prevent post-traumatic ischemia may be useful in the acute treatment of spinal cord injury.

Effects of a single large dose of methylprednisolone sodium succinate on experimental posttraumatic spinal cord ischemia. Dose-response and time-action analysis

The ability of a single large intravenous dose of methylprednisolone sodium succinate (MPSS: 15, 30, or 60 mg/kg) to modify the evolution of lumbar spinal cord ischemia in cats undergoing a contusion injury of 500 gm-cm is examined. Repeated measurements of spinal cord blood flow (SCBF) in the dorsolateral funiculus were made via the hydrogen clearance technique before and for 4 to 5 hours after injury. The mean preinjury SCBF for all animals was 12.29 +/- 0.77 ml/100 gm/min. Following injury, SCBF began to decrease progressively in vehicle-treated animals to a level of 7.71 ml/100 gm/min, a fall of 37.3%. In contrast, cats that received a 30-mg/kg intravenous dose of MPSS at 30 minutes after injury maintained SCBF within normal limits (p less than 0.05 at 3 and 4 hours after contusion). A 15-mg/kg MPSS dose was less effective at preventing posttraumatic white matter ischemia, and a 60-mg/kg dose was essentially ineffective. It was determined that the 30-mg/kg MPSS dose was optimal for supporting SCBF when the drug was given at 30 minutes after spinal trauma, and a second series of experiments was carried out to examine the ability of this dose, when given at longer latencies, to improve decreased flow. Methylprednisolone given at 1 1/2 hours after injury in four cats produced a slight (12.7%) but transient improvement in SCBF, and when administered at 4 1/2 hours in another three animals was totally ineffective. These results show that MPSS in a 30-mg/kg dose can prevent posttraumatic spinal cord ischemia. However, it would appear that the ability of the steroid to reverse the ischemia once it has developed is limited, and probably lost, within a few hours of onset. This further suggests that the ischemic process is irreversible and underscores the need for early treatment with a large MPSS dose in order to prevent full development of ischemia and to promote neurological recovery.

Methylprednisolone preservation of motor nerve function during early degeneration

Intensive pretreatment of cats with methylprednisolone acetate (8 mg/kg, i.m. once daily for 7 days) was found to significantly preserve the functional capabilities of degenerating soleus motor nerve terminals, as measured at 48 h after motor axon section in the in vivo soleus nerve-muscle preparation. This effect is similar to that reported previously for triamcinolone, another glucocorticoid.

Alteration of shock titration thresholds in the cat following intrathecal substance P administration

Substance P (SP) was injected intrathecally (10 or 100 micrograms) into cats previously implanted with nerve-stimulating electrodes and the effect on shock titration thresholds was evaluated. Elevated shock thresholds were observed in 5 of 8 cats following the 100 micrograms dose of SP. In addition, one cat exhibited a decreased threshold and two cats showed a triphasic (increase, decrease, increase) response. Overt behavioral effects of intrathecal SP were mild, but suggested that injection of the drug was aversive.

Lateral reticular formation as a site for morphine- and clonidine-induced hypotension

The possible role of the lateral reticular formation (LRF) in morphine-induced hypotension was investigated. Morphine (5-10 micrograms) microinjected into 15 of 25 sites in the LRF of anesthetized cats reduced mean (+/- S.E.) arterial pressure by 18.4 +/- 2.1 mmHg. Morphine applied microiontophoretically on LRF neurons had a predominately inhibitory effect on LRF cells, decreasing spontaneous rate in 51%. Since the LRF has been suggested as a site of action for clonidine-induced hypotension, clonidine was also applied microiontophoretically to these neurons. Of the cells evaluated, 43% were inhibited by clonidine. Individual cells typically responded in the same manner to morphine and clonidine. An inhibition of LRF cells by morphine and clonidine is consistent with their hypotensive action and the tonic vasopressive role assigned to the LRF. Collectively, these results suggest that the LRF is a site at which morphine and clonidine may produce their hypotensive effect.

Relationships between blood ethanol levels and ethanol-induced changes in cortical EEG power spectra in the rat

Adult female Sprague-Dawley rats were implanted with chronic cortical and temporalis muscle electrodes and/or intravenous cannulas. After acute ethanol administration, dose-dependent linear declines in blood ethanol concentration were found. Ethanol-induced increases in EEG spectral power in the 0 - 4 Hz band persisted long after blood ethanol levels and declined to zero; therefore, we found no correlation. Acute ethanol administration also produced an initial drop in 8 - 13 Hz spectral power. Then, as blood ethanol levels declined, 8 - 13 Hz spectral power increased toward normal; a significant negative linear correlation was found.

Evaluation of biological dressings

The use of biological dressings in the treatment of burns is reviewed. Many theoretical advantages were initially proposed, but time and controlled studies have disproved some of them. Biological dressings are nevertheless helpful in relieving pain, protecting exposed vital structures, reducing exudative protein and erythrocyte loss and evaporative water loss, protecting granulation tissue, antibacterial activity, and testing a recipient bed's readiness for grafting. They probably offer no benefit in final wound debridement and primary dressings for partial thickness burns or split skin donor sites. There is no conclusive evidence that biological dressings alter epithelialization or the rate of formation of granulation tissue. A review of our last 100 cases at the Bothin Burn Center generally supports these conclusions with evidence of the superiority of homografts over heterografts.

Testosterone-estradiol-binding globulin in patients with Turner's syndrome: effects of estrogens and acute growth hormone administration

The TeBG activity of plasma from patients with Turner's syndrome was measured quantitatively using polyacrylamide gel electrophoresis. Human growth hormone administration did not significantly change the plasma TeBG levels. However, oral replacement therapy with estrogens elevated plasma TeBG within 3 days; after 9 days these levels reached a maximum of three- to four-fold greater than that observed at a time prior to therapy.