Trial of a novel prostacyclin analog, UT-15, in patients with severe intermittent claudication

Prostacyclin is an endothelially derived vasodilator and inhibitor of platelet aggregation. Despite its therapeutic potential for peripheral arterial disease, the short half-life and chemical instability are barriers to routine therapy. Accordingly, prostacyclin analogs are being evaluated in patients with peripheral arterial disease. State-of-the-art non-invasive ultrasonography allows for serial testing of the hemodynamic effects of vasoactive drugs. The safety, efficacy and hemodynamic effects of UT-15, a novel, long-acting prostacyclin analog, were studied in patients with severe intermittent claudication. A total of eight patients with stable severe intermittent claudication, Fontaine classes IIb-III, were admitted to the hospital for intravenous infusion of UT-15. A symptom-limited, dose-escalation protocol was instituted, beginning with placebo and then with increasing dosage at 60-min intervals, followed by a 2-h period of maintenance dose at the maximum well-tolerated infusion rate. The hemodynamic response in the lower limbs was assessed with serial ultrasonography, segmental arterial pressures and pulse volumes. Blood flow in the common femoral artery increased 29% (p = 0.003) by the end of the maintenance period and remained above baseline throughout the washout period (p = 0.044). Blood velocity in the lower limb increased in most of the peripheral arteries. These increases achieved statistical significance in the common femoral artery (p = 0.025) and anterior tibial artery (p = 0.019), and approached significance in the popliteal artery (p = 0.062). In two of four patients in whom blood flow was undetectable before the infusion, arterial blood flow at the ankle level became apparent on ultrasonography during maintenance infusion. UT-15 infusion improved the pulse volume recording (p = 0.016) but the ankle/brachial index did not change significantly. Common side effects at peak dose included headache and nausea. There were no serious adverse events attributable to UT-15 treatment. In most patients, the optimal infusion rate was 10-20 ng/kg per min. In conclusion, ultrasonography is a novel approach for assessing the hemodynamic response to vasoactive agents. UT-15 is well tolerated when given for up to 2 h and increases arterial blood flow and velocity in patients with severe intermittent claudication.

IQ scores of treatment-resistant schizophrenia patients before and after the onset of the illness

In this study we examined the correlations of actual pre-morbid IQ scores (obtained from routine educational assessments) and estimated current IQ scores in 27 treatment-resistant schizophrenia patients. Pre-morbid (mean = 93) and current (mean = 83) IQ scores were significantly correlated (r = 0.807, P < 0.0001), while duration of illness (10-40 years) was unrelated to the magnitude of IQ score decline (r = -0.103, P = 0.575). These data suggest that pre-morbid IQ test scores are highly predictive of post-morbid scores.

Auditory sensory dysfunction in schizophrenia: imprecision or distractibility?

BACKGROUND

Schizophrenia is associated with large effect-size deficits in auditory sensory processing, as reflected in impaired delayed-tone matching performance. The deficit may reflect either impaired sensory precision, which would be indicative of neural dysfunction within auditory sensory (temporal) regions, or of increased distractibility, which would be indicative of impaired prefrontal function. The present study evaluates susceptibility of schizophrenic subjects to same-modality distraction to determine whether patients fit a "bitemporal" or "prefrontal" model of sensory dysfunction.

METHODS

Tone-matching ability was evaluated in 15 first-episode patients, 18 outpatients with chronic illness, and 21 patients in long-term residential care, relative to 32 nonpsychiatric controls of a similar age. A staircase procedure determined individual thresholds for attaining criterion level correct performance.

RESULTS

Tone-matching thresholds in the absence of distractors were significantly elevated in patients in long-term residential care relative to all other groups (P<.001). The effect size (d) of the difference relative to controls was extremely large (SD, 1.95). Schizophrenic patients, even those with elevated tone-matching thresholds, showed no increased susceptibility to auditory distraction (P =.42). Deficits in tone-matching performance in subjects with chronic illness could not be attributed to medication status or level of symptoms.

CONCLUSIONS

These findings suggest that sensory processing dysfunction in schizophrenia is particularly severe in a subgroup of patients who can be considered poor-outcome based on their need for long-term residential treatment. Furthermore, the absence of increased auditory distractibility argues against prefrontal dysfunction as an origin for auditory sensory imprecision in schizophrenia. Arch Gen Psychiatry. 2000;57:1149-1155.

Chemoprevention of human actinic keratoses by topical 2-(difluoromethyl)-dl-ornithine

Alpha-2-(Difluoromethyl)-dl-ornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, has been shown to suppress skin carcinogenesis in murine models after oral or topical administration. We designed a randomized, placebo-controlled study using a topical hydrophilic ointment formulation with or without 10% (w/w) DFMO. Forty-eight participants with moderate-severe actinic keratoses (AKs) on their forearms (i.e., at least 10 well-circumscribed lesions on the lateral surface) completed a 1-month run-in on placebo ointment. Before randomization, all lateral forearm AKs were circled, counted, photographed, and skin biopsies were obtained for DFMO and polyamine levels. Then participants were randomized to receive DFMO ointment on the right versus the left forearm and placebo hydrophilic ointment on the contralateral forearm twice daily for 6 months. DFMO was not detected in the blood of any subject, and there were no systemic toxicities. None of a subsample of 17 placebo forearms had measurable concentrations of DFMO, whereas 13 of the corresponding DFMO-treated forearms had high DFMO skin levels. As compared with placebo, the 6-month DFMO treatment caused a 23.5% reduction in the number of AKs (P = 0.001) as well as significant suppression of AK biopsy spermidine levels (26%; P = 0.04). Seven of the 48 (14.6%) participants experienced severe (2; 4.2%) or moderate (5; 10.4%) inflammatory reactions on their DFMO-treated arms which required dosing modification. Topical DFMO for 6 months can reduce the number of AK lesions and skin spermidine concentrations in high-risk participants and deserves additional study as a skin cancer chemopreventive agent.

The use of naproxen in the treatment of children with rheumatic fever

We evaluated the efficacy and safety of naproxen (10-20 mg/kg/d) for the treatment of arthritis and fever related to rheumatic fever in 19 children. Fever and arthritis resolved within a median of 1 day of beginning treatment (range, 1-2 and 1-30 days, respectively). The sole patient with prolonged arthritis had small joint involvement. No gastrointestinal, dermatologic, liver, or renal side effects were observed. None of the patients developed carditis over the following 6 months. Naproxen appears to be effective for the treatment of arthritis and fever related to rheumatic fever and is well tolerated.

Quantitation of benzo[a]pyrene-DNA adducts by postlabeling with 14C-acetic anhydride and accelerator mass spectrometry

Quantitation of carcinogen-DNA adducts provides an estimate of the biologically effective dose of a chemical carcinogen reaching the target tissue. In order to improve exposure-assessment and cancer risk estimates, we are developing an ultrasensitive procedure for the detection of carcinogen-DNA adducts. The method is based upon postlabeling of carcinogen-DNA adducts by acetylation with 14C-acetic anhydride combined with quantitation of 14C by accelerator mass spectrometry (AMS). For this purpose, adducts of benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide (BPDE) with DNA and deoxyguanosine (dG) were synthesized. The most promutagenic adduct of BPDE, 7R,8S,9R-trihydroxy-10S-(N(2)-deoxyguanosyl)-7,8,9, 10-tetrahydrobenzo[a]pyrene (BPdG), was HPLC purified and structurally characterized. Postlabeling of the BPdG adduct with acetic anhydride yielded a major product with a greater than 60% yield. The postlabeled adduct was identified by liquid chromatography-mass spectrometry as pentakis(acetyl) BPdG (AcBPdG). Postlabeling of the BPdG adduct with 14C-acetic anhydride yielded a major product coeluting with an AcBPdG standard. Quantitation of the 14C-postlabeled adduct by AMS promises to allow detection of attomolar amounts of adducts. The method is now being optimized and validated for use in human samples.

Isolation and characterization of the epothilone biosynthetic gene cluster from Sorangium cellulosum

The epothilone biosynthetic gene cluster was isolated from Sorangium cellulosum strain SMP44. The gene cluster contains seven genes and spans approx. 56kb. The genes encoding the PKS, epoA, epoC, epoD, epoE, and epoF, are divided into nine modules. The EpoB protein is a non-ribosomal peptide synthetase (NRPS) that catalyzes formation of the thiazole found in the epothilones. EpoK is a P450 enzyme responsible for the epoxidation of epothilones C and D to epothilones A and B, respectively. EpoK was expressed in Escherichia coli, and the purified protein was shown to convert epothilone D to epothilone B in vitro.

Myeloperoxidase-catalyzed redox-cycling of phenol promotes lipid peroxidation and thiol oxidation in HL-60 cells

Various types of cancer occur in peroxidase-rich target tissues of animals exposed to aryl alcohols and amines. Unlike biotransformation by cytochrome P450 enzymes, peroxidases activate most substrates by one-electron oxidation via radical intermediates. This work analyzed the peroxidase-dependent formation of phenoxyl radicals in HL-60 cells and its contribution to cytotoxicity and genotoxicity. The results showed that myeloperoxidase-catalyzed redox cycling of phenol in HL-60 cells led to intracellular formation of glutathionyl radicals detected as GS-DMPO nitrone. Formation of thiyl radicals was accompanied by rapid oxidation of glutathione and protein-thiols. Analysis of protein sulfhydryls by SDS-PAGE revealed a significant oxidation of protein SH-groups in HL-60 cells incubated in the presence of phenol/H2O2 that was inhibited by cyanide and azide. Additionally, cyanide- and azide-sensitive generation of EPR-detectable ascorbate radicals was observed during incubation of HL-60 cell homogenates in the presence of ascorbate and H2O2. Oxidation of thiols required addition of H2O2 and was inhibited by pretreatment of cells with the inhibitor of heme synthesis, succinylacetone. Radical-driven oxidation of thiols was accompanied by a trend toward increased content of 8-oxo-7,8-dihydro-2'-deoxyguanosine in the DNA of HL-60 cells. Membrane phospholipids were also sensitive to radical-driven oxidation as evidenced by a sensitive fluorescence HPLC-assay based on metabolic labeling of phospholipids with oxidation-sensitive cis-parinaric acid. Phenol enhanced H2O2-dependent oxidation of all classes of phospholipids including cardiolipin, but did not oxidize parinaric acid-labeled lipids without addition of H2O2. Induction of a significant hypodiploid cell population, an indication of apoptosis, was detected after exposure to H2O2 and was slightly but consistently and significantly higher after exposure to H2O2/phenol. The clonogenicity of HL-60 cells decreased to the same extent after exposure to H2O2 or H2O2/phenol. Treatment of HL-60 cells with either H2O2 or H2O2/phenol at concentrations adequate for lipid peroxidation did not cause a detectable increase in chromosomal breaks. Detection of thiyl radicals as well as rapid oxidation of thiols and phospholipids in viable HL-60 cells provide strong evidence for redox cycling of phenol in this bone marrow-derived cell line.

Calcium-dependent PAF-stimulated generation of reactive oxygen species in a human keratinocyte cell line

During inflammation and other pathological states, the lipid mediator platelet-activating factor (PAF) and reactive oxygen species (ROS) are both generated. We have been investigating the effect of exogenous PAF on ROS formation in the human keratinocyte cell line (HaCaT). ROS production, measured using luminol-enhanced chemiluminescence (CL), proved to be rapid, transient, PAF receptor-mediated, and totally dependent on an increase in intracellular Ca2+ ([Ca2+]i) and on the presence of extracellular Ca2+. Repeated administration of PAF resulted in refractoriness to the agonist in terms of both capacities to increase [Ca2+]i and generate ROS. The cells, however, continued to respond fully to other stimulants (bradykinin, epidermal growth factor, thapsigargin). The PAF-induced increases in [Ca2+]i (monitored using the fluorescent probe Fluo-3) were also rapid and transient and paralleled those of ROS generation. Relatively specific inhibitors of potential ROS-producing systems were administered in an attempt to characterize the ROS producing system(s). Inhibitors of xanthine oxidase, phospholipase A2, lipoxygenase, cyclooxygenase and NO synthase did not interfere with PAF evoked ROS. The flavoprotein inhibitor diphenyleneiodonium and the mitochondrial cytochrome oxidase inhibitor KCN, prevented generation of ROS, making NAD(P)H a candidate for the electron source of the ROS and the mitochondria a potential major site of formation.

Predictors of treatment response from a first episode of schizophrenia or schizoaffective disorder

OBJECTIVE

This study examined the treatment response of patients with first-episode schizophrenia and schizoaffective disorder and potential predictors of response.

METHOD

First-episode patients were assessed on measures of psychopathology, cognition, social functioning, and biological parameters and treated according to a standardized algorithm.

RESULTS

One hundred eighteen patients (52% male, mean age 25.2 years) entered the study. The cumulative percentage of patients responding by 1 year was 87%; the median time to response was 9 weeks. The following variables were significantly associated with less likelihood of response to treatment: male sex, obstetric complications, more severe hallucinations and delusions, poorer attention at baseline, and the development of parkinsonism during antipsychotic treatment. Variables not significantly related to treatment response were diagnosis (schizophrenia versus schizoaffective disorder), premorbid functioning, duration of psychotic symptoms prior to study entry, baseline disorganization, negative and depressive symptoms, baseline motor function, akathisia and dystonia during treatment, growth hormone and homovanillic acid measures, psychotic symptom activation to methylphenidate, and magnetic resonance measures.

CONCLUSIONS

Patients with first-episode schizophrenia and schizoaffective disorder have high rates of response to antipsychotic treatment; there are specific clinical and pathobiologic predictors of response.

Predictors of relapse following response from a first episode of schizophrenia or schizoaffective disorder

BACKGROUND

We examined relapse after response to a first episode of schizophrenia or schizoaffective disorder.

METHODS

Patients with first-episode schizophrenia were assessed on measures of psychopathologic variables, cognition, social functioning, and biological variables and treated according to a standardized algorithm. The sample for the relapse analyses consisted of 104 patients who responded to treatment of their index episode and were at risk for relapse.

RESULTS

Five years after initial recovery, the cumulative first relapse rate was 81.9% (95% confidence interval [CI], 70.6%-93.2%); the second relapse rate was 78.0% (95% CI, 46.5%-100.0%). By 4 years after recovery from a second relapse, the cumulative third relapse rate was 86.2% (95% CI, 61.5%-100.0%). Discontinuing antipsychotic drug therapy increased the risk of relapse by almost 5 times (hazard ratio for an initial relapse, 4.89 [99% CI, 2.49-9.60]; hazard ratio for a second relapse, 4.57 [99% CI, 1.49-14.02]). Subsequent analyses controlling for antipsychotic drug use showed that patients with poor premorbid adaptation to school and premorbid social withdrawal relapsed earlier. Sex, diagnosis, obstetric complications, duration of psychotic illness before treatment, baseline symptoms, neuroendocrine measures, methylphenidate hydrochloride challenge response, neuropsychologic and magnetic resonance imaging measures, time to response of the initial episode, adverse effects during treatment, and presence of residual symptoms after the initial episode were not significantly related to time to relapse.

CONCLUSIONS

There is a high rate of relapse within 5 years of recovery from a first episode of schizophrenia and schizoaffective disorder. This risk is diminished by maintenance antipsychotic drug treatment.

Usefulness of intravenous metoprolol to prevent syncope induced by head-up tilt

Intravenous metoprolol was found to be significantly more effective than placebo in preventing head-up tilt-table induced neurally mediated syncope. The reproducibility of acute tilt-table testing is only 63% and suggests caution in the interpretation of acute drug testing during tilt-table studies.

Relative bioavailability of coenzyme Q10 formulations in human subjects

The relative bioavailability of typical commercially available forms of coenzyme Q10 (CoQ10) was compared with that of Q-Gel, a new solubilized form of CoQ10, in human subjects in two separate trials. In the first, standard softgel capsules containing CoQ10 suspension in oil, powder-filled hardshell capsules and powder-based tablets were tested along with Q-Gel using a daily dosage of 120 mg for three weeks. The baseline plasma CoQ10 values were all very tight (0.50-0.52 microgram/mL) and after three weeks the values were 1.37, 1.63 and 1.60 micrograms/mL for the first three products and 3.31 micrograms/mL for Q-Gel. The relative bioavailability calculated using the areas under the plasma CoQ10 curve (AUC) were (micrograms/mL x time in days) 7.16 (100%), 8.97 (125%), 9.19 (128%) and for Q-Gel 22.86 (319%). The second trial, carried out to replicate the findings in the first, employed only two groups, namely the standard softgel capsules containing the suspension and Q-Gel, and the duration was extended to four weeks. Plasma CoQ10 values were: baseline 0.40 and 0.38 and after four weeks 1.26 and 2.80; the corresponding AUCs were: 8.33 (100%) and 22.75 (273%). Thus, the data from both the trials show that Q-Gel, the new solubilized form of CoQ10, is vastly superior to typical commercially available preparations of CoQ10. This means much lower doses of Q-Gel will be required to rapidly reach and maintain adequate blood CoQ10 values than with any of the other currently available products.

Structure of secreted aspartic proteinases from Candida. Implications for the design of antifungal agents

Pathogens of the genus Candida can cause life threatening infections in immuno-compromised patients. The three-dimensional structures of two closely related secreted aspartic proteinases from C. albicans complexed with a potent (Ki = 0.17 nM) inhibitor, and an analogous enzyme from C. tropicalis reveal variations on the classical aspartic proteinase theme that dramatically alter the specificity of this class of enzymes. The novel fungal proteases present: i) an 8 residue insertion near the first disulfide (Cys45-Cys50, pepsin numbering) that results in a broad flap extending towards the active site; ii) a seven residue deletion replacing helix hN2 (Ser110-Tyr114), which enlarges the S3 pocket; iii) a short polar connection between the two rigid body domains that alters their relative orientation and provides certain specificity; and i.v.) an ordered 12 residue addition at the carboxy terminus. The same inhibitor (A-70450) binds in an extended conformation in the two variants of C. albicans protease, and presents a branched structure at the P3 position. However, the conformation of the terminal methylpiperazine ring is different in the two crystals structures. The implications of these findings for the design of potent antifungal agents are discussed.

Crosstalk between elevation of [Ca2+]i, reactive oxygen species generation and phospholipase A2 stimulation in a human keratinocyte cell line

The aim of the study was to explore the possible interrelationship between reactive oxygen species (ROS) formation and cPLA2 activation and the mediator role that [Ca2+]i may play in these processes in the human keratinocyte cell line, HaCaT. HaCaT cells can be invoked to transiently produce ROS by epidermal growth factor (EGF), thapsigargin (TPG) and the Ca(2+)-ionophore, A23187. These 3 agonists transiently increase [Ca2+]i with characteristic kinetics and magnitude. TPG and A23187 each activates on its own [3H]AA release from prelabeled cells, whereas EGF on its own has no effect on [3H]AA release. However, EGF augments [3H]AA release invoked by TPG or A23187 several fold. EGF activates MAP kinase cascades in HaCaT cells, leads to ROS formation and induces relatively small (1.6 fold) elevation in [Ca2+]i, whereas A23187 and TPG lead to a substantial elevation in [Ca2+]i (2.5 to 5 fold) and to ROS formation. Both have a minor effect on MAP kinase activation. The synergism in PLA2 activation by EGF and TPG or A23187, and the sensitivity of [3H]AA release to N-acetylcysteine (NAC) and dithiothreitol (DTT) (potent reducing agents) or to DPI (an inhibitor of FAD-dependent oxidases) lead to the suggestion that ROS formation, elevation of [Ca2+]i and PLA2 activation are causally related. Since we show that elevation of [Ca2+]i is a prerequisite for both ROS and PLA2 activation, it is possible that these processes contribute to the toxicity (apoptosis) exerted by chronic elevation of [Ca2+]i.

Involvement of reactive oxygen species in phospholipase A2 activation: inhibition of protein tyrosine phosphatases and activation of protein kinases

Activators of PKC in combination with vanadate induce massive formation of reactive oxygen species. The formation of ROS leads to suppression of protein tyrosine phosphatase activity and consequently to enhanced protein tyrosine phosphorylation. This culminates in the activation of the MAP-K cascade and of PLA2 (Scheme 1).

[Drowning in Israel--1990-1992]

There are no epidemiological studies of drowning in Israel in the scientific literature, despite prominent reports in the media. We analyzed the extent of mortality from drowning in Israel during 1990-92, attempting to identify and characterize groups at high risk, and to determine trends and differences between Israel and other countries. Computerized death certificate files were provided by the Israel government Central Bureau of Statistics; deaths from drowning were included among external causes codes E-830, 832, E-910, E-954, E-964, E-984. In Israel, as in the United States, mortality from drowning is the fourth cause of death among all unintentional causes, and the second cause in age-groups 1-24, ranking after transport accidents. During 1990-92 there were 1.2 drownings a year/100,000 population. The highest rates were found among young non-Jews 15-24 years old (7.8/100,000) and among elderly Jews (3.5/100,000). Unintentional drowning accounted for 89% of all deaths; while about 10% were defined as suicides. Males had a rate almost 3 times greater than females, and the among Arabs was 2.4 times greater than among Jews. The 1990-92 drowning rate was slightly lower than in previous years. Drowning rates in Israel are lower than in the United States, except in the elderly. Apparently the principal reason for this difference is difference in sites of drowning. In Israel most drownings occur in the sea, so site data are unavailable for international comparisons. Careful consideration of the categories (E-codes) included in the rates, and of local registration procedures, is necessary for international comparisons. Foreign workers, tourists and other nonresidents are not included in national vital statistics. But estimations based on Ministry of Interior sources show that foreign workers (most, recent arrivals) during the last few years are an extremely high risk group. Population-based drowning rates are not an accurate estimation of drowning risk, since universal exposure to the "opportunity to drown" is assumed.