Are there gender differences in the prescribing of hypnotic medications for insomnia?

Gender differences in the prescribing patterns of general classes of medications for insomnia were examined. The classes of medications included: zopiclone, antidepressants, benzodiazepines, antihistamines and no medication. The sample comprised a sub-set of respondents from 2620 questionnaires of the Canadian Multicentre Sleep Database. Respondents for this database were contacted through physicians, announcements in the media and local pharmacies. The results indicated that gender alone was not associated with differential prescribing for insomnia, nor was gender associated with patterns of medication use such as frequency of taking medication, length of use, taking more or less medication than prescribed or attempts to stop taking medication. Demographic factors were included in the analysis and age and marital status were associated with different prescribing patterns for men and women with insomnia. It is possible that physicians refer to stereotypic expectations when prescribing hypnotics.

The crystal structure of Escherichia coli MoeA, a protein from the molybdopterin synthesis pathway.

MoeA is involved in synthesis of the molybdopterin cofactor, although its function is not yet clearly defined. The three-dimensional structure of the Escherichia coli protein was solved at 2.2 A resolution. The locations of highly conserved residues among the prokaryotic and eukaryotic MoeA homologs identifies a cleft in the dimer interface as the likely functional site. Of the four domains of MoeA, domain 2 displays a novel fold and domains 1 and 4 each have only one known structural homolog. Domain 3, in contrast, is structurally similar to many other proteins. The protein that resembles domain 3 most closely is MogA, another protein required for molybdopterin cofactor synthesis. The overall similarity between MoeA and MogA, and the similarities in a constellation of residues that are strongly conserved in MoeA, suggests that these proteins bind similar ligands or substrates and may have similar functions.

A prospective evaluation of empiric versus protocol-based sedation and analgesia.

STUDY OBJECTIVE: To compare empiric and protocol-based therapies of sedation and analgesia in terms of pharmacologic cost, effects on mechanical ventilation and intensive care unit (ICU) stay, and quality of sedation and analgesia. DESIGN: Prospective study. SETTING: A 24-bed medical-surgical-neurologic ICU. PATIENTS: Seventy-two patients evaluated during empiric therapy and 86 during protocol-based therapy. INTERVENTION: Assessment of data collected for 4 months before and 5 months after an evidence-based sedation and analgesia protocol was implemented. MEASUREMENTS AND MAIN RESULTS: Protocol adherence rate was 83.7%. The hourly cost (Canadian dollars) of sedation was less with protocol-based therapy ($5.68 +/- 4.27 vs $7.69 +/- 5.29, p<0.01) likely due to increased lorazepam use. Pharmacologic cost savings may be negated since sedation duration tended to be longer (122.7 +/- 142.8 vs 88.0 +/- 94.8 hrs, p<0.1) and extubation may have been delayed (61.6 +/- 97.4 vs 39.1 +/- 54.7 hrs, p=0.13) with protocol use. Duration of ICU stay after sedation was discontinued was not significantly different before and after protocol implementation. With the protocol, however, the percentage of modified Ramsay sedation scores representing discomfort decreased from 22.4 to 11% (p<0.001) and the percentage at a score of 4 increased from 17.2% to 29.6% (p<0.01). The percentage of modified visual analog measurements representing pain decreased from 9.6 to 5.9% (p<0.05) with the protocol. When data were stratified according to duration of sedation, the benefits and delayed extubation associated with protocol-based therapy were limited to patients requiring long-term sedation. CONCLUSION: Compliance with this protocol reduced drug costs and enhanced the quality of sedation and analgesia for patients requiring long-term sedation. Protocol-based therapy with lorazepam may have delayed extubation but did not delay ICU discharge.

A Canadian multicenter study of three fixed doses of controlled-release ipsapirone in outpatients with moderate to severe major depression.

Ipsapirone, an azapirone with 5-hydroxytryptamine (5-HT1A) partial agonist activity, has been shown in preliminary studies to be effective in the treatment of major depressive disorder. This 8-week, randomized, double-blind study compared the efficacy, safety, and tolerability of three fixed doses of controlled-release ipsapirone (10-, 30-, and 50-mg dose once daily) with placebo in 410 patients with moderate to severe major depression (Hamilton Rating Scale for Depression [HAM-D] score > or = 20). The 10-mg ipsapirone treatment arm was discontinued early in the study. A total of 390 patients were eligible for evaluation in the intent-to-treat sample. The primary efficacy variable was the change in HAM-D total score from baseline to visit 8. There was no significant difference in efficacy in the two treatment groups versus the placebo group. The overall treatment response, defined as a 50% decrease in the HAM-D total score from baseline, was 43% with ipsapirone 50 mg given once daily, 34% with ipsapirone 30 mg given once daily, and 35% with placebo. In subanalyses, ipsapirone 50 mg given once daily was superior to placebo according to the HAM-D Core Depression (mood, guilt, interest, psychomotor activity) subtotal (p = 0.0453) and Melancholic item (p = 0.0225). Ipsapirone 30 mg given once daily was superior to placebo only in patients with moderate depression (baseline HAM-D total score < or = 25; p = 0.0100). The most common adverse effect in all groups was headache. The only dose-dependent adverse effects were dizziness and nausea.

The effect of surfactants on the rate of decarboxylation of p-aminosalicylic acid in acidic aqueous solutions.

p-Aminosalicylic acid, which exists in four ionic forms and whose decarboxylation is well known, was used as a model drug to investigate the effects of surfactants with different charges on its stability. The greatest reduction in the rate of decarboxylation at 50 degrees C occurred when the charge on the micelles was opposite to that of the charge on the drug or when both the drug and the micelle had a neutral charge. Thus, at the highest surfactant concentration, 3 or 5% (w/v), there was a 59% reduction in the rate at pH 2.68 in the presence of the nonionic surfactant polyoxyethylene 24 monocetyl ether, 69% reduction in the rate at pH 4.88 in the presence of the cationic surfactant hexadecyl trimethylammonium bromide, and a 43% reduction at pH 1.01 in the presence of the anionic surfactant sodium cetyl sulfate. The decrease in the rate of decarboxylation was attributed to the partitioning of the drug into the micelles, which provided a phase for improved stabilization. Partition coefficients and rate constants for decarboxylation of the drug inside the micelles were calculated.

Scanning-deletion analysis of the extracellular domain of the TGF-beta receptor type II.

There are three main types of receptors for TGF-beta termed receptor type I, type II and type III. TGF-beta receptor type II has a crucial role in the cell's responsiveness to TGF-beta as it is mandatory for the TGF-beta binding to the signaling complex (receptor type I and type II). Here we have used a scanning-deletion mutagenesis approach to determine the core binding domain of the extracellular domain of receptor type II that is required for interaction with TGF-beta. Deletions of three amino acids were systematically introduced at intervals of five amino acids in order to scan the N- and C-terminus of the extracellular domain of the receptor. We find that the N-terminal region which is devoid of cysteine residues is not critical for ligand binding. Similarly, the C-terminal region, i.e., the amino acids flanking the transmembrane domain, are dispensable for binding. These results suggest that the central 100 amino acid span that is rich in cysteine residues is the core binding domain for TGF-beta.

Mutagenesis analysis of the membrane-proximal ligand binding site of the TGF-beta receptor type III extracellular domain.

There are two TGF-beta binding subdomains in the extracellular domain of receptor type III (proximal and distal in relation to the transmembrane domain). Here we present an extension of our analysis of the proximal binding site of receptor type III. Due to the original deletion mutagenesis strategy, our proximal binding site contained 19 amino acids from the N-terminal part of the receptor. By deleting these, we demonstrated that they did not contribute to the binding ability of the proximal binding site. We also produced a soluble, secreted form of the proximal binding site and demonstrated that it was able to bind TGF-beta. Finally, we analyzed the role of the three asparagine residues (580, 591, 595) that are located in the region of the receptor that is necessary for expression of a functional proximal binding site, and found that mutation of these residues individually to alanine did not affect ligand binding.

Transforming growth factor-beta receptor expression on endothelial cells: heterogeneity of type III receptor expression.

Recent studies of whole animal responses have defined a role for circulating TGF-beta in the preservation and stabilization of microvascular endothelial function (Lefer et al. [1993] Proc. Natl. Acad. Sci. U.S.A., 90:1018-1022; Pfister et al. [1992] J. Exp. Med., 176:265-269). In order to determine which TGF-beta receptor types are responsible for this endothelial cell responsiveness, we used an affinity-labeling technique with 125I-TGF-beta 1 and -beta 2 to characterize TGF-beta receptors on five different endothelial cell cultures: early passage bovine lung and rat epididymal fat pad microvascular endothelial cells (BLMEC and REEC), established endothelial cell lines from bovine adrenal medulla capillaries (EJG), fetal bovine heart (FBHE), and bovine pulmonary artery (CPAE). Since it is known that endothelial cells from different parts of the vasculature vary with respect to cell surface antigen expression (McCarthy et al. [1991] Trends Pharmacol. Sci., 12:462-467; Augustin et al. [1994] Bioessays, 16:901-906), it is important to compare TGF-beta receptor expression on microvascular and macrovascular endothelial cells. We observed 85 kDa and 200-400 kDa labeled receptor bands and analyzed their relationship to the cloned Type II and III receptors using peptide antibodies. We used dithiothreitol and phosphoinositol-phospholipase C pretreatments to establish whether the 65 kDa labeled band which we observed corresponded to the Type I receptor or a glycophosphotidylinositol-linked binding protein. The results demonstrated that microvascular but not macrovascular endothelial cells express high levels of the Type III receptor. This differential expression of the Type III receptor indicates that distinct anatomical segments of the vasculature have distinct TGF-beta receptor profiles. The presence of the Type III receptor on micro- but not macrovascular endothelial cells may account for the reportedly different potency of TGF-beta 1 and TGF-beta 2 on these two endothelial cell types. Analysis of the 85 kDa and 65 kDa affinity-labeled bands revealed that all the endothelial cells express the Type II receptor and a band consistent with the presence of a dithiothreitol-sensitive Type I receptor. Two isoform-specific phosphoinositol-phospholipase C releasable TGF-beta binding proteins were also detected: a 60 kDa protein on one micro- (EJG) and one macro- (FBHE) vascular endothelial cell line and a 150/180 kDa protein on the macrovascular cell lines (FBHE and CPAE). These studies emphasize the heterogeneous nature of endothelial cells and underline the importance of using microvascular endothelial cells when examining TGF-beta responses related to microvascular function.

Differential illness intrusiveness associated with sleep-promoting medications.

Differences in daytime sleepiness, lifestyle disruptions, and emotional distress were compared across nine groups taking sleep-promoting substances. Groups included individuals taking zopiclone (n = 274), amitriptyline (n = 107), lorazepam (n = 258), oxazepam (n= 141), diphenhydramine HCl (n = 99), triazolam(n = 137), long acting benzodiazepines (n = 120), temazepam (n = 176), and miscellaneous other medications (n = 286). Data were gathered by self-report, using standardized instruments in a mail-back questionnaire procedure. Respondents included the first 1,598 participants enrolled in a Canadian multicentre project, including six sites attached to academic psychiatric units. Results indicated that quality of life effects differed across groups in both daytime sleepiness and lifestyle disruptions (illness intrusiveness), but not in depressive symptoms. Daytime sleepiness was significantly higher among people taking diphenhydramine HCl as compared to temazepam, zopiclone, lorazepam, and oxazepam. Illness intrusiveness was significantly higher among patients taking amitriptyline as compared to those taking triazolam, oxazepam, long-acting benzodiazepines, and zopiclone. It may be useful to inform patients of differences in psychosocial outcomes when prescribing hypnotic medications.

Mapping of the ligand binding domain of the transforming growth factor beta receptor type III by deletion mutagenesis.

Transforming growth factor beta (TGF-beta) receptor type III is a membrane-anchored proteoglycan that binds TGF-beta via the core protein. We have determined, by deletion mutagenesis of the receptor type III, the minimal essential region of the extracellular domain that is capable of binding TGF-beta. Nine deletion mutants were produced, six of which are expressed on the cell surface and bind TGF-beta. We find that the shortest of these active mutants, which retains only 253 of the 785 amino acids of the extracellular domain, binds TGF-beta with the same affinity as the full-length receptor. These results indicate that the ligand binding domain lies proximal to the transmembrane domain and is functionally independent from the rest of the extracellular domain. We have determined from the mutants that one of the potential glycosaminoglycan attachment sites in the receptor type III is not utilized. Results from the nonglycosylated mutants confirm that the glycosaminoglycan chains are not required for the folding, targeting, and TGF-beta binding activity of the receptor. Moreover, we present evidence for dimerization and multimerization of the receptor.

Cognitive-behavioral therapy of panic disorder with secondary major depression: a preliminary investigation.

Controlled studies indicate that cognitive-behavioral therapy eliminates panic attacks in greater than 80% of patients who suffer from panic disorder. However, because most of the screening procedures used in those studies called for excluding patients who were depressed, a question arises as to the extent to which these results apply to patients who are clinically depressed in addition to having panic attacks. Accordingly, an attempt was made in the present study to determine whether or not panic patients who are clinically depressed could be treated as successfully as those who are not clinically depressed. Two multiple baseline A-A1-A-B across-subjects designs were used, one to test 8 panic Ss with major depression and the second to test 7 panic Ss without major depression. In Baseline (A), Ss monitored their panic attacks daily. During the A1 phase, a program of information on panic attacks presented as psychotherapy was instituted to assess the effects of nonspecific factors, followed by a second baseline phase (A). Cognitive-behavioral therapy (B) was then introduced. Results showed that cognitive-behavioral therapy was significantly superior to information-based therapy in the reduction of panic attacks. No significant differences were found between depressed and nondepressed patients.

The transforming growth factor beta receptors types I, II, and III form hetero-oligomeric complexes in the presence of ligand.

Transforming growth factors beta (TGF-beta s) are disulfide-linked dimers. In Rat-1 cells both radioiodinated TGF-beta 1 and -beta 2 bind to and can be chemically cross-linked to type I and II receptors (which are thought to mediate effects of cell growth suppression and gene activation), to type III proteoglycan receptors, and to a novel approximately 50-kDa protein. After detergent solubilization of cells that were cross-linked with radioiodinated TGF-beta, antibodies specific for the type II receptor precipitated labeled receptor types I and III as well as type II. In these cells, the type III receptor is the predominant TGF-beta-binding protein, and antibodies specific for it precipitate mainly this cross-linked receptor. Thus, in the presence of TGF-beta ligand, receptor types II and III and types II and I form heteromeric complexes. The majority of the type III receptor does not associate with receptor types I and II, probably reflecting the relative amounts of the three receptors on the surface of Rat-1 cells. Since TGF-beta 1 but not TGF-beta 2 binds to the exoplasmic domain of the type II receptor in the absence of the type III receptor, and since both TGF-beta 1 and -beta 2 bind with high affinity to the type III receptor, we suggest that TGF-beta 2, and possibly TGF-beta 1, bind initially to the type III receptor. The TGF-beta 2-type III receptor complex would then interact with a type II receptor, thus modulating the affinity of the type II receptor for TGF-beta 2.

Baculovirus expression of mammalian G protein alpha subunits.

Complementary DNAs encoding three subtypes of the alpha subunit (alpha i-1, alpha o and alpha s) of rat guanyl nucleotide regulatory proteins were used to construct recombinant baculoviruses which direct high-level expression of the corresponding proteins in cultured Sf9 insect cells. The expressed proteins were recognized by polyclonal antisera specific for the different alpha chains, and co-migrated with the native proteins from rat brain membranes in immunoblotting analyses. Soluble and particulate forms of all three immunoreactive alpha chains were observed following ultracentrifugation of cell lysates. Biosynthetic radiolabelling of infected cells with [35S]methionine or [3H]myristate showed that both soluble and particulate forms of alpha i-1 and alpha o were myristoylated; in contrast, alpha s did not incorporate myristate. The soluble fractions from cells expressing alpha chains showed high levels of GTP-binding activity over that observed in uninfected cells, or in cells infected with wild-type virus. The peak expression levels observed at 72 h post-infection were highest for alpha o at ca. 400 pmol of GTP-gamma-35S/mg protein, or roughly 2% of the total soluble protein. The results of this work show that the baculovirus system can be employed for high-level production of mammalian G protein alpha chains which retain GTP-binding activity and are appropriately modified by myristoylation.

Regulating the introduction of new chemicals under section 5 of TSCA: improving the efficiency of the process and reducing potential injury in the workplace through the use of operational MSDS and exposure limits.

The Toxic Substances Control Act (TSCA) authorizes the EPA to take appropriate actions to ensure that new and existing chemicals do not pose "unreasonable risk" to health or the environment. Section 2(b)(3) of the Act directs the Agency to accomplish this objective in a manner that does "not impede unduly or create unnecessary economic barriers to technological innovation." In recent years, critics have felt that the EPA has failed to achieve these primary goals of TSCA. This paper considers some of the reasons for this criticism and advocates an alternate approach of exposure limits and operationally sufficient controls to assist in achieving these goals. An illustration of how this alternate approach might work under practical conditions is presented, using as an example a new chemical substance from the class of acrylate monomers. These concepts and risk assessments provide data for a better design of future studies according to good laboratory practice and quality assurance.

An increase in adenylate cyclase activity precedes DNA synthesis in cultured vascular smooth muscle cells.

Adenylate cyclase activity in cultured rat aortic vascular smooth muscle cells showed a linear correlation with the rate of DNA synthesis. When smooth muscle cells were rendered quiescent by shifting them from a serum-supplemented medium to a medium containing low concentrations of plasma, the cells could be stimulated to proliferate by the addition of serum or by addition of a crude preparation of platelet-derived growth factor. DNA synthesis began at 16 hours and was maximal at 24 hours. Prior to synthesis of DNA there was an increase in adenylate cyclase activity with a peak at 12 hours. Adenylate cyclase activity returned to basal level before DNA synthesis began. The increase in adenylate cyclase activity was not blocked by cycloheximide. Adenylate cyclase activity could also be increased by incubating vascular smooth muscle cells with cholera toxin; however, the time course and magnitude of this increase was different from that caused by growth stimulants. Cholera toxin caused a slight increase in DNA synthesis at 16 hours, but was also cytotoxic to smooth muscle cells. An increase in adenylate cyclase activity may be a prerequisite for the progression from G1 to S.

Glycolic Acid Labeling During Photosynthesis with CO(2) and Tritiated Water.

Chlorella pyrenoidosa were allowed to photosynthesize for short periods of time in the presence of (14)CO(2) and HTO. Analysis of tritium and (14)C labeling of photosynthetic intermediate compounds showed that the T/(14)C ratio of glycolic acid was comparable to that of intermediate compounds of the photosynthetic carbon reduction cycle when photosynthesis was performed in nearly 100% oxygen and only slightly higher under steady-state conditions. It is concluded that formation of labeled glycolic acid as a consequence of its proposed hydrogen transport role in photosynthesis is quantitatively of limited importance compared to the net synthesis of glycolic acid from CO(2).