Using observations and source specific model tracers to characterize pollutant transport during FRAPPÉ and DISCOVER-AQ

Transport is a key parameter in air quality research and plays a dominant role in the Colorado Northern Front Range Metropolitan Area (NFRMA), where terrain induced flows and recirculation patterns can lead to vigorous mixing of different emission sources. To assess different transport processes and their connection to air quality in the NFRMA during the FRAPPÉ and DISCOVER-AQ campaigns in summer 2014, we use the Weather Research and Forecasting Model with inert tracers. Overall, the model represents well the measured winds and the inert tracers are in good agreement with observations of comparable trace gas concentrations. The model tracers support the analysis of surface wind and ozone measurements and allow for the analysis of transport patterns and interactions of emissions. A main focus of this study is on characterizing pollution transport from the NFRMA to the mountains by mountain-valley flows and the potential for recirculating pollution back into the NFRMA. One such event on 12 August 2014 was well captured by the aircraft and is studied in more detail. The model represents the flow conditions and demonstrates that during upslope events, frequently there is a separation of air masses that are heavily influenced by oil and gas emissions to the North and dominated by urban emissions to the South. This case study provides evidence that NFRMA pollution not only can impact the nearby Foothills and mountain areas to the East of the Continental Divide, but that pollution can "spill over" into the valleys to the West of the Continental Divide.

Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves

Haematopoiesis is a process that is responsible for generating sufficient numbers of blood cells in the circulation and in tissues. It is central to maintenance of homeostasis within an animal, and is critical for defense against infection. While haematopoiesis is common to all animals possessing a circulatory system, the specific mechanisms and ultimate products of haematopoietic events vary greatly. Our understanding of this process in non-vertebrate organisms is primarily derived from those species that serve as developmental and immunological models, with sparse investigations having been carried out in other organisms spanning the metazoa. As research into the regulation of immune and blood cell development advances, we have begun to gain insight into haematopoietic events in a wider array of animals, including the molluscs. What began in the early 1900's as observational studies on the morphological characteristics of circulating immune cells has now advanced to mechanistic investigations of the cytokines, growth factors, receptors, signalling pathways, and patterns of gene expression that regulate molluscan haemocyte development. Emerging is a picture of an incredible diversity of developmental processes and outcomes that parallels the biological diversity observed within the different classes of the phylum Mollusca. However, our understanding of haematopoiesis in molluscs stems primarily from the three most-studied classes, the Gastropoda, Cephalopoda and Bivalvia. While these represent perhaps the molluscs of greatest economic and medical importance, the fact that our information is limited to only 3 of the 9 extant classes in the phylum highlights the need for further investigation in this area. In this review, we summarize the existing literature that defines haematopoiesis and its products in gastropods, cephalopods and bivalves.

Effect of Renal Function on the Pharmacokinetics of Palifermin

Palifermin (deltaN23KGF) decreases the incidence, severity, and duration of oral mucositis. The objectives of this open-label study were to evaluate the pharmacokinetics of single-dose palifermin in subjects with varying degrees of renal function. A single 90-mcg/kg intravenous dose of palifermin was administered to 31 subjects with varying levels of renal function (normal to requiring hemodialysis). Pharmacokinetic analyses were conducted using serum palifermin concentrations. There was considerable overlap in mean palifermin serum clearance among the groups, ranging from 318 to 495 mL/h/kg, indicating that the level of renal function did not affect clearance in humans; thus, no dose adjustment of palifermin is indicated for patients with renal dysfunction.

Neuraxial labor analgesia in an obese parturient with influenza A H1N1

We describe the use of epidural analgesia in a 39-year-old G2P1 parturient presenting at 38(+6) weeks estimated gestation with confirmed influenza A H1N1 and superimposed bilateral pneumonia. Although the patient had an uncomplicated intra- and post-partum course, little is known about the safety of performing neuraxial analgesia or anesthesia in patients with influenza. The prevalence of viremia and possible translocation of blood-borne virus to the central nervous system are discussed.

Further characterization of passively transferred resistance to Schistosoma mansoni in the snail intermediate host Biomphalaria glabrata

A heat-labile plasma factor from genetically resistant 10-R2 Biomphalaria glabrata snails confers passively transferred resistance (PTR) to Schistosoma mansoni when injected into susceptible snails within 24-hr of exposure to miracidia. However, no additional details on PTR have emerged since the initial 1984 report, nor has the plasma resistance factor been characterized. In the present study, new information is provided on the occurrence of resistance factor in plasma of additional types of snails, effect of "priming" resistant plasma donors by prior exposure to miracidia, duration of PTR, molecular weight of resistance factor, and fate of sporocysts in snails with PTR. Susceptible NIH albino snails injected 24 hr prior to exposure to miracidia with individual samples of plasma from a different strain (Salvador B. glabrata) or a different species (B. obstructa) of nonsusceptible snail displayed infection prevalences of 49% or 59% of control levels, respectively, whereas injections of homologous plasma had no effect. PTR was not enhanced by prior exposure of resistant Salvador plasma donors to miracidia. Unexpectedly, PTR induced by injections of Salvador plasma persisted for at least 21 days. The molecular weight of the resistance factor(s) was between 10 and 30 kDa, based on results of centrifugal ultrafiltration. A significantly higher proportion of dead sporocysts occurred in histological sections of tentacles from snails injected with Salvador plasma than in tentacles of snails injected with NIH albino plasma at 7 days postexposure to miracidia. Most dead sporocysts in Salvador plasma-injected snails were undergoing gradual degeneration, rather than rapid, hemocyte-mediated destruction, as occurred in Salvador snails.

Effects of a novel glucagon receptor antagonist (Bay 27-9955) on glucagon-stimulated glucose production in humans

AIMS/HYPOTHESIS

To study the effects of a specific glucagon receptor antagonist (Bay 27-9955), on plasma glucose concentrations and rates of glucose production in response to hyperglucagonaemia in humans.

METHODS

The study was conducted as a two-dose [Low Dose Bay 27-9955 70 mg, (n = 6), High Dose Bay 27-9955 200 mg, (n = 8)], double blind, placebo controlled, crossover study. Basal glucose production was measured after an overnight fast with [6,6-2H]. At 0 min Bay 27-9955 or placebo was administered and at 120 min an infusion of somatostatin [0.1 microg x (kg x min)(-1)], insulin [24 pmol x (m2 x min)(-1)] and glucagon [3 ng x (kg x min)(-1)] was initiated.

RESULTS

Basal plasma glucose concentrations were about 5 mmol/l and basal rates of glucose production were about 13 micromol x (kg x min)(-1). During the hyperglucagonaemic period, plasma glucagon concentrations doubled to 100 pg/ml, plasma glucose concentration increased by 75 % to a peak of about 10 mmol/l and glucose production doubled to about 23 micromol x (kg x min)(-1) (p < 0.0001 vs basal). In the High Dose Group these effects of glucagon were markedly blunted, plasma glucose concentrations were 7.6 +/- 1.1 mmol/l (p = 0.012 vs placebo) and rates of glucose production increased minimally to 15.3 +/- 1.9 micromol x (kg-min)(-1) (p < 0.0003 vs placebo]. In the Low Dose Group, there was a proportional decrease in the effects of Bay 27-9955 on these parameters.

CONCLUSION/INTERPRETATION

Bay 27-9955 is an effective and safe glucagon antagonist in humans. Given the potentially important role of glucagon in increasing glucose production and gluconeogenesis in patients with Type II (non-insulin-dependent) diabetes mellitus this agent could represent an innovative class of therapeutic agents for the disease.

The influence of age and gender on the pharmacokinetics of moxifloxacin

OBJECTIVE

Moxifloxacin is a new 8-methoxyfluoroquinolone with a broad antibacterial spectrum. The purpose of the present study was to determine the effects of age and gender on pharmacokinetics, surrogate pharmacodynamics, safety and tolerability of a single dose of moxifloxacin.

DESIGN

This was a randomised, double-blind, placebo-controlled, parallel-group single dose trial in young and elderly healthy volunteers.

PATIENTS AND PARTICIPANTS

The study included 36 volunteers in 3 age and gender groups: young males (mean age 32 years), elderly males (mean age 74 years), and elderly females (mean age 74 years).

METHODS

Participants received either a single 200mg oral dose of moxifloxacin (8/group) or placebo (4/group). Blood samples for moxifloxacin pharmacokinetics were obtained before and up to 48 hours after administration. Urine samples were collected for pharmacokinetics, and volunteers were monitored for clinical adverse events and laboratory abnormalities.

RESULTS

Maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) were higher in elderly females than in elderly males; however, when normalised for bodyweight, these pharmacokinetic parameters were not significantly different between the groups. Moreover, the plasma pharmacokinetics in elderly males were not meaningfully different from those in young males. Elimination half-life averaged 12 to 13 hours for the 3 groups. Surrogate pharmacodynamic measures were derived using AUC/MIC (minimal inhibitory concentration) and Cmax/MIC ratios. These assessments indicated that, given the linear pharmacokinetics of moxifloxacin previously demonstrated, a dose of 400mg would produce mean Cmax/MIC values in the different subgroups ranging from 10.4 to 15.4 for an MIC of 0.25, and 20.8 to 30.8 for an MIC of 0.125. The corresponding ranges of projected AUC/MIC ratios would be 112 to 158 for an MIC of 0.25, and 224 to 314 for an MIC of 0.125. The accepted target values of AUC/MIC and Cmax/MIC for quinolones are 125 and 10, respectively. There were no serious adverse events or differences in adverse event profiles between the groups.

CONCLUSIONS

Moxifloxacin does not exhibit age- or gender-dependent pharmacokinetics. Oral doses of 200 to 400mg yield effective antibacterial concentrations on the first day of administration.

Hematopoietic tissue allografts in Biomphalaria glabrata (Mollusca: Pulmonata) induce humoral immunity to Schistosoma mansoni

We examined a potential mechanism for adoptively transferred resistance against Schistosoma mansoni in schistosome-susceptible snails receiving allografts of the hematopoietic amebocyte-producing organ (APO) from a schistosome-resistant strain of Biomphalaria glabrata. Susceptible NIH albino snails first were implanted with the APO from resistant Salvador strain donors. At 14 days post-implantation, cell-free plasma was isolated from APO recipients and injected into a second group of NIH albino snails. Controls were injected with plasma from NIH albino snails that previously had received implants of Salvador mantle, an immunologically inert tissue. Finally, plasma recipients, along with untampered (non-injected) controls, were exposed to miracidia of S. mansoni and subsequently monitored for infection. A significantly lower prevalence of infection occurred in the group injected with plasma from APO recipients (53%) in comparison with that in untampered controls (100%) or in snails receiving plasma from mantle recipients (97%). These results suggest that adoptively transferred resistance in B. glabrata results from secretion of soluble resistance factor(s) by the implant, rather than, or in addition to, formation of a hemocyte chimera having cytotoxic donor hemocytes.

Effect of miracidial dose on adoptively transferred resistance to Schistosoma mansoni in the snail intermediate host, Biomphalaria glabrata

Adoptively transferred resistance to Schistosoma mansoni in the snail intermediate host Biomphalaria glabrata was measured as a function of miracidial challenge dose. Schistosome-susceptible snails implanted with the amebocyte-producing organ (APO) from resistant donors showed 29 and 39% prevalences of infection after challenge with 5 and 10 miracidia, respectively, but 68-83% prevalences when exposed to 25-200 miracidia. Prevalences in control (untampered) susceptible snails ranged from 97 to 100% at the different miracidial doses. Higher infection prevalences at elevated doses suggest that a range of transferred resistance occurs and possibly that low levels of APO-derived plasma factors or hemocytes in some recipients can be overwhelmed by larger numbers of parasites.

Short-term immunoisolation of incompatible xenografts in a snail, Biomphalaria glabrata

Hearts of the snails Physa virgata and Biomphalaria glabrata were implanted into the hemocoel of B. glabrata. Implants either were microencapsulated in 2.5% agarose or were unencapsulated. Unencapsulated xenografts from P. virgata underwent complete necrosis within 3 days post-implantation (DPI), whereas allografts were still alive at 7 DPI. In the case of microencapsulated implants, both allografts and xenografts were alive at 3 DPI, showing 4.8 and 14.9% pyknosis among myofiber nuclei, respectively. These results suggest that direct cytotoxicity by hemocytes, rather than toxic plasma factors or donor-recipient physiological incompatibility, is responsible for rapid xenograft death. However, both types of microencapsulated grafts were necrotic at 7 DPI. This necrosis may have resulted from oxygen deprivation brought about both by the agarose and by the heterotopic implantation site, inasmuch as microencapsulated allografts and xenografts cultured in saline for 7 days showed only 1.98 and 30% pyknosis, respectively.

Rescue of sporocysts of Schistosoma mansoni in nonsusceptible Biomphalaria by head-foot transplantation into susceptible snails

To measure the longevity of sporocysts of Schistosoma mansoni in nonsusceptible snails (13-16-R1 and Salvador strains of Biomphalaria glabrata, and Biomphalaria obstructa), the head-foot (HF) of miracidia-exposed snails was transplanted into the hemocoel of a susceptible NIH albino recipient at 1-36 days postexposure (DPE). Recipient snails which were not exposed to miracidia then were monitored for infection transferred by the implant, and infection prevalences in recipients of HF transplants from nonsusceptible donors were compared to those in snails implanted with an HF from NIH albino donors. Transplants from NIH albino snails between 1 to 15 DPE infected 98% of recipients. Similarly, at 1 DPE, 69-85% of transplants from nonsusceptible snails contained viable sporocysts, as shown by resulting patent infections in the recipients. Recipient infection prevalence, and presumably numbers of transplants containing viable sporocysts, declined as a function of DPE, and by 5-9 DPE this decrease was significant for all 3 types of nonsusceptible donors. However, viable sporocysts still occurred in B. obstructa and 13-16-R1 B. glabrata as late as 19 and 20 DPE, respectively, and in Salvador B. glabrata as late as 33 DPE. Thus, sporocysts persist in nonsusceptible snails considerably longer than suggested by results of previous histological studies.

Factors affecting adoptive transfer of resistance to Schistosoma mansoni in the snail intermediate host, Biomphalaria glabrata

We examined potential variables affecting adoptive transfer of resistance to Schistosoma mansoni in Biomphalaria glabrata implanted with amebocyte-producing organs (APOs) from resistant snails. Transplants of 7 tissues other than the APO (heart, kidney, mantle, albumin gland, brain, digestive gland, and gonad) did not transfer resistance, suggesting a unique property of this structure. Only APOs from donors previously exposed to miracidia transferred resistance, although whether this is evidence for a priming effect or merely the elimination of susceptible donors is not known. Variability in the donor and in the implant itself apparently was unimportant, inasmuch as implants from small or large snails or from 2 separate donors all conferred similar levels of resistance. Recipients of APOs from 2 additional resistant strains of B. glabrata, 10-R2 and Salvador, also displayed resistance. However, no resistance was transferred by APOs from schistosome-refractory B. obstructa. Histological examination of implants removed from recipients that either did or did not show transferred resistance revealed no differences in mitotic activity. Furthermore, implanted APOs from B. obstructa displayed no mitotic activity. Finally, reexposure of snails with transferred resistance to a large dose of miracidia caused infection in 70%, suggesting that either transferred resistance is transitory or it can be overwhelmed.

Pharmacokinetics of a once-daily oral dose of moxifloxacin (Bay 12-8039), a new enantiomerically pure 8-methoxy quinolone

The pharmacokinetics, safety, and tolerability of oral moxifloxacin, a new 8-methoxy quinolone, were assessed in a randomized, double-blind, placebo-controlled study in which healthy male and female volunteers received either 400 mg of moxifloxacin once daily (n = 10) or a placebo once daily (n = 5) for 10 days. Plasma moxifloxacin concentrations on days 1 and 10 were measured by high-performance liquid chromatography and fluorometric detection. Standard pharmacokinetic parameters were estimated by noncompartmental methods. Natural logarithmic estimates for each pharmacokinetic variable of each subject were analyzed by a two-way analysis of variance. Hematology, blood chemistry, vital signs, and adverse events were monitored, and electrocardiograms (ECG) were performed. Plasma moxifloxacin concentrations of predicted therapeutic relevance were achieved in this study. For day 1, the mean maximum concentration of drug in serum (C(max)) and the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) were 3. 4 mg/liter and 30.2 mg. h/liter, respectively. Corresponding means on day 10 were 4.5 mg/liter and 48 mg. h/liter, respectively. On day 10, the mean elimination half-life was approximately 12 h. Plasma moxifloxacin concentrations exceeded the MIC for Streptococcus pneumoniae throughout the 24-h dosing period. The day 1 and day 10 mean AUC/MIC ratios were 121 and 192, respectively, and the mean C(max)/MIC ratios were 13 and 18, respectively. Moxifloxacin was well tolerated; no clinically relevant changes in the standard laboratory tests, vital signs, or ECG were observed. Pharmacokinetic parameters demonstrated linearity, and estimates of pharmacokinetic/pharmacodynamic ratios (AUC/MIC and C(max)/MIC) indicate that the regimen of 400-mg once daily should be effective for treating a variety of infections. Moxifloxacin was found to be safe and well tolerated in healthy volunteers when it was given as a single daily 400-mg dose for 10 days.

Absolute bioavailability of moxifloxacin

Moxifloxacin (BAY 12-8039) is an investigational 8-methoxy-fluoroquinolone with broad-spectrum gram-positive and gram-negative activity. To determine the absolute bioavailability of moxifloxacin, this open-label, randomized, crossover study compared the pharmacokinetic characteristics of a single 100-mg dose administered either orally or intravenously as a 60-minute infusion in 10 healthy male volunteers (mean age [+/- SD], 29.3+/-7.1 years; mean weight [+/- SD], 77.7+/-8.7 kg). Geometric mean values for oral/IV moxifloxacin were as follows: peak serum concentration, 1.15/1.34 mg/L, and area under the concentration-time curve over 48 hours, 9.86/10.89 mg x h/L. The geometric mean absolute bioavailability of oral moxifloxacin was 91.8%. Mean renal clearance was approximately 2.3 L/h after administration of both the single oral and IV formulations, which suggests lack of active tubular secretion of moxifloxacin. Both the oral and IV formulations were well tolerated, with 5 reported possible or probable drug-related adverse events; they included headache, nausea, and localized urticaria. In summary, a single oral dose of moxifloxacin was extensively absorbed in healthy young men. Further studies are necessary in actual patients to confirm the viability of IV to oral conversion at the same dose of moxifloxacin.

Cloning and overexpression of glycosyltransferases that generate the lipopolysaccharide core of Rhizobium leguminosarum

The lipopolysaccharide (LPS) core of the Gram-negative bacterium Rhizobium leguminosarum is more amenable to enzymatic study than that of Escherichia coli because much of it is synthesized from readily available sugar nucleotides. The inner portion of the R. leguminosarum core contains mannose, galactose, and three 3-deoxy-D-manno-octulosonate (Kdo) residues, arranged in the order: lipid A-(Kdo)2-Man-Gal-Kdo-[O antigen]. A mannosyltransferase that uses GDP-mannose and the conserved precursor Kdo2-[4'-32P]lipid IVA (Kadrmas, J. L., Brozek, K. A., and Raetz, C. R. H. (1996) J. Biol. Chem. 271, 32119-32125) is proposed to represent a key early enzyme in R. leguminosarum core assembly. Conditions for demonstrating efficient galactosyl- and distal Kdo-transferase activities are now described using a coupled assay system that starts with GDP-mannose and Kdo2-[4'-32P]lipid IVA. As predicted, mannose incorporation precedes galactose addition, which in turn precedes distal Kdo transfer. LPS core mutants with Tn5 insertions in the genes encoding the putative galactosyltransferase (lpcA) and the distal Kdo-transferase (lpcB) are shown to be defective in the corresponding in vitro glycosylation of Kdo2-[4'-32P]lipid IVA. We have also discovered the new gene (lpcC) that encodes the mannosyltransferase. The gene is separated by several kilobase pairs from the lpcAB cluster. All three glycosyltransferases are carried on cosmid pIJ1848, which contains at least 20 kilobase pairs of R. leguminosarum DNA. Transfer of pIJ1848 into R. meliloti 1021 results in heterologous expression of all three enzymes, which are not normally present in strain 1021. Expression of the lpc genes individually behind the T7 promoter results in the production of each R. leguminosarum glycosyltransferase in E. coli membranes in a catalytically active form, demonstrating that lpcA, lpcB, and lpcC are structural genes.

Evolution of rhizobia by acquisition of a 500-kb symbiosis island that integrates into a phe-tRNA gene

Nodulation and nitrogen fixation genes of Mesorhizobium loti are encoded on the chromosome of the bacterium. Nevertheless, there is strong evidence that these genes can be transferred from an inoculant strain to nonsymbiotic mesorhizobia in the field environment. Here we report that the chromosomal symbiotic element of M. loti strain ICMP3153 is transmissible in laboratory matings to at least three genomic species of nonsymbiotic mesorhizobia. The element is 500 kb in size, integrates into a phe-tRNA gene, and encodes an integrase of the phage P4 family just within its left end. The entire phe-tRNA gene is reconstructed at the left end of the element upon integration, whereas the 3' 17 nucleotides of the tRNA gene are present as a direct repeat at the right end. We termed the element a symbiosis island on the basis of its many similarities to pathogenicity islands. It may represent a class of genetic element that contributes to microbial evolution by acquisition.

Schistosoma mansoni infection inhibits maturation of ovotestis allografts in Biomphalaria glabrata (Mollusca:Pulmonata)

The posterior tip of juvenile snails, consisting of immature ovotestis, vesicular connective tissue, and digestive gland acini, all surrounded by body wall, was implanted into the hemocoel of allogeneic adult Biomphalaria glabrata. Recipient snails were either uninfected or had been infected 15 days previously with Schistosoma mansoni. Graft recipients were dissected at 30 or 60 days postimplantation (DPI), and the implants, along with preimplantation controls, were examined histologically. The gonads in preimplantation controls consisted of a partially coiled collecting canal partitioned dorsally by connective tissue septa and contained mainly spermatogonia-like cells and small oocytes. In uninfected recipients, implanted gonads underwent rapid development, i.e., had formed mature acini and were carrying out vigorous gametogenesis, both spermatogenesis and oogenesis, by 30 DPI. At 60 DPI, numbers of spermatozoa had increased substantially in most implants. In infected recipients, relatively little development or gametogenesis occurred at either 30 or 60 DPI, and oogenesis was more strongly inhibited than spermatogenesis. Except for 1 implanted gonad (out of 25) that had undergone necrosis at 60 DPI and a second otherwise healthy 60-day implant partially encapsulated at its cut surface (both in uninfected recipients), no significant hemocytic response occurred against the allografts.

Comparison of several types of allografts in Biomphalaria glabrata (Mollusca: Pulmonata)

Interpretation of prior studies on molluscan allografts is complicated by the variety of experimental methods used and recurring reports of acute rejection of digestive gland implants. In this study, allografts of adult digestive gland, saccular kidney, mantle, albumin gland, brain, ovotestis, heart, or amoebocyte-producing organ (APO) were implanted into the hemocoel of Biomphalaria glabrata snails, and their histological condition at 60 days post implantation (DPI) was compared with that of preimplantation tissues. Also, digestive gland tissue, still surrounded by body wall, was implanted from immature donors and examined at 120 DPI. All 60-day allografts maintained some degree of normal cell and tissue structure, and most displayed additional evidence of viability, i.e., contraction (heart), hyperplasia (APO), gametogenesis (ovotestis), secretion (albumin gland, digestive gland, and kidney), shell deposition (mantle), or neuroma formation (brain). Recipient hemocytic reaction was minimal or absent, except that in three of six ovotestis implants and five of seven digestive gland implants, variable numbers of acini were undergoing phagocytosis by hemocytes or had been reduced to granulomas. Among seven implants examined at 120 DPI, digestive gland acini were found in five (with one instance of hemocytic encapsulation). Thus, in this study, acute rejection of allografts did not occur. Although the observed hemocytic reactions could be viewed as evidence of chronic graft rejection, the inconsistent and protracted nature of these responses suggests instead that they represent resorption of degenerating tissue damaged by nonimmunological effects, e.g., mechanical trauma, heterotopic location, or autolysis.

Cocaine effects on digital blood flow and diffusing capacity for carbon monoxide among chronic cocaine users

PURPOSE

To determine the acute effects of intravenous (i.v.) cocaine on primarily digital skin blood flow and diffusion capacity for carbon monoxide (CO), and secondarily on subjective and cardiovascular measures.

PATIENTS AND METHODS

A double-blind, Latin-square, placebo-controlled, dose-response study was conducted in an inpatient general clinical research center and clinical pharmacology unit of a university teaching hospital. Twelve adult males with histories of illicit drug use including i.v. cocaine received 0, 25, and 50 mg of i.v. cocaine given as 1-minute infusions, on 3 consecutive test days. Digital cutaneous blood flow was determined via laser doppler flowmetry and skin temperature. Diffusing capacity for carbon monoxide (DCO) was measured with standard techniques. Subjective responses were measured by oral report of a numerical ranking of strength of drug effect. Heart rate and blood pressure responses were measured by electronic sphygmomanometer.

RESULTS

A maximal decrease in skin blood flow occurred at 2 to 3 minutes after infusion, and was not distinguished among drug conditions. Blood flow returned to baseline more rapidly after placebo than after cocaine: 7 minutes (placebo), 35 minutes (25 mg cocaine), 50 minutes (50 mg cocaine). Skin temperature decreased by 1.25 degrees C after placebo and by 2.75 and 3.25 degrees C after 25 and 50 mg of cocaine, respectively. DCO changed by -1.02 (mean) +/- 0.25 (standard deviation), 0.16 +/- 1.22, and 0.21 +/- 1.63 ml/min/mm Hg following placebo, 25, and 50 mg of cocaine, respectively. Typical subjective, chronotropic, and pressor responses to cocaine were demonstrated, and these occurred in close temporal relationship to digital blood flow and skin temperature responses.

CONCLUSIONS

The digital cutaneous circulation is highly sensitive to vasoconstrictor effects of cocaine. Pulmonary blood volume tends to be preserved after i.v. cocaine. Subjective effects and cardiovascular responses occur in concert with peripheral blood flow changes. The peripheral vasoconstrictor effects have implications for cocaine users with concurrent vasospastic or vasculopathic disorders.

Abuse liability of testosterone

Anabolic-androgenic steroids (AAS) are used by athletes to enhance performance and physique. Case reports and observations propose that AAS have mood elevating properties and that chronic use leads to addiction. The aim of this study was to evaluate the subjective and physiological effects of single doses of testosterone. In a double-blind fashion, according to a balanced Latin square, 10 paid adult male volunteers received doses of i.m. testosterone (50, 100 and 200 mg), morphine (10 mg) or placebo for five consecutive days. Subjective and physiological responses were measured during each drug condition. Testosterone produced no significant changes in self-reported or observed measures, unlike morphine, which produced statistically significant changes in several measures, including 'feel the drug', 'like the drug' and 'feel high'. There were no adverse effects of administering high doses of testosterone. In conclusion, single doses of testosterone are devoid of the usual pharmacologic effects that are associated with abuse.

Effects of naltrexone on response to intravenous cocaine, hydromorphone and their combination in humans

This study evaluated the effects of i.v. cocaine, hydromorphone and their combination, and assessed the ability of oral naltrexone, an opioid antagonist, to modulate these effects. Volunteers with cocaine and heroin abuse histories (n = 8) participated in this placebo-controlled, cross-over study while residing on a closed research unit. Daily treatment with capsules containing placebo or naltrexone in ascending doses (3.125, 12.5, 50 and 200 mg) were given for 7-day periods. In thrice weekly experimental sessions, cocaine, hydromorphone and their combination were given in random order. Drug doses were given in an ascending order 1 hr apart as follows: cocaine at 0,20 and 40 mg, hydromorphone at 0, 1.5 and 3.0 mg, and the combination of 0 and 0 mg, 20 mg cocaine and 1.5 mg hydromorphone and 40 mg cocaine and 3.0 mg hydromorphone. Hydromorphone and cocaine produced distinct pharmacodynamic profiles, and the combination produced effects similar to both drugs. In some cases, the magnitude of effects produced by the combination was greater than that produced by either drug alone. Naltrexone produced dose-related blockade of hydromorphone effects, but did not after any of the physiological or subjective effects of cocaine. All naltrexone doses partially attenuated the effects of the combination and this appeared to be attributable to selective opioid blockade. These data do not support the use of naltrexone as a treatment for cocaine abuse, but suggest it may be useful for treating patients with concurrent cocaine and heroin abuse.

Fate of Schistosoma mansoni in Biomphalaria obstructa

Histological sections of Biomphalaria obstructa snails exposed to miracidia of Schistosoma mansoni revealed that although viable sporocysts occurred in 6 of 9 snails at 3 days postexposure (DPE), all were dead by 7 DPE. Most dead sporocysts appeared to have degenerated slowly rather than having been killed by host hemocytic responses, which were minimal. What appeared to be amorphous remnants of sporocysts could still be found at 31 DPE. In 7 of 10 snails infected simultaneously with S. mansoni and Echinostoma paraensei, viable schistosome sporocysts occurred at 7 DPE, possibly as a result of interference with hemocyte function by the echinostome. However, in snails exposed to E. paraensei 48 hr prior to S. mansoni, no viable schistosome sporocysts were found at 7 DPE. Biomphalaria obstructa may be only temporarily susceptible to infection with E. paraensei, rediae of which undergo degeneration, hemocyte-mediated destruction, or both by 7-9 DPE.

Four unnamed species of nonsymbiotic rhizobia isolated from the rhizosphere of Lotus corniculatus

Previously, we found that genetically diverse rhizobia nodulating Lotus corniculatus at a field site devoid of naturalized rhizobia had symbiotic DNA regions identical to those of ICMP3153, the inoculant strain used at the site (J. T. Sullivan, H. N. Patrick, W. L. Lowther, D. B. Scott, and C. W. Ronson, Proc. Natl. Acad. Sci. USA 92:8985-8989, 1995). In this study, we characterized seven nonsymbiotic rhizobial isolates from the rhizosphere of L. corniculatus. These included two from plants at the field site sampled by Sullivan et al. and five from plants at a new field plot adjacent to that site. The isolates did not nodulate Lotus species or hybridize to symbiotic gene probes but did hybridize to genomic DNA probes from Rhizobium loti. Their genetic relationships with symbiotic isolates obtained from the same sites, with inoculant strain ICMP3153, and with R. loti NZP2213T were determined by three methods. Genetic distance estimates based on genomic DNA-DNA hybridization and multilocus enzyme electrophoresis were correlated but were not consistently reflected by 16S rRNA nucleotide sequence divergence. The nonsymbiotic isolates represented four genomic species that were related to R. loti; the diverse symbiotic isolates from the site belonged to one of these species. The inoculant strain ICMP3153 belonged to a fifth genomic species that was more closely related to Rhizobium huakuii. These results support the proposal that nonsymbiotic rhizobia persist in soils in the absence of legumes and acquire symbiotic genes from inoculant strains upon introduction of host legumes.

Location, DNA sequence and transcriptional analysis of the DNA polymerase gene of orf virus

Degenerate oligonucleotides representing conserved regions of various DNA polymerases hybridized to a region located 26 kb from the left end of the orf virus (OV) strain NZ-2 genome. DNA sequence analysis of this region revealed a 3024 bp open reading frame able to encode a protein with 56 percent amino acid identity to the DNA polymerase of vaccinia virus (VAC) and with significant homology to other DNA polymerases. Early transcripts derived from the open reading frame were detected in RNA purified from OV-infected cells, and 5' ends were mapped to a region 8-19 nt downstream from an A/T-rich sequence that resembles VAC early promoters. Unlike the VAC gene, the OV DNA polymerase makes almost exclusive use of G/C coding options. Attempts to substitute the activity of the OV DNA polymerase for its VAC counterpart were unsuccessful. This may indicate that the OV DNA polymerase is incompatible with VAC accessory proteins.

Enhancement of cocaine's abuse liability in methadone maintenance patients

The present study was conducted to determine whether methadone maintenance alters the pharmacodynamic effects of single doses of cocaine. Twenty-two current users of IV cocaine who were not seeking treatment for their illicit cocaine use participated while living on a research unit. Eleven were maintained on methadone 50 mg PO daily as treatment for their opioid abuse; 11 were opioid abusers who were not physically dependent on opioids and who provided opioid-free urines throughout the study. Each subject received acute cocaine challenge doses of 0, 12.5, 25, and 50 mg intravenously in random order under double-blind conditions in separate test sessions. Physiologic and subject-rated responses were measured before injection and for 2 h after. In the methadone maintenance group, cocaine challenge sessions occurred 15.5 h after the daily methadone dose. There were significant differences between the methadone-dependent and nondependent groups: 1) baseline differences related to chronic methadone administration and not associated with cocaine administration (lower respiration rates and pupil diameter; higher skin temperature) and 2) differences in response to cocaine administration; cocaine-induced increases in subject ratings of Drug Effect, Rush, Good Effects, Liking, and Desire for Cocaine and in heart rate were greater in the methadone maintenance patients compared to the non-dependent group. These results indicate that the positive subjective effects and some physiological effects of cocaine are enhanced in methadone-maintained individuals, suggesting a pharmacological basis for the high rates of cocaine abuse among methadone maintenance patients.

5-HT3 receptor antagonism and psychoactivity

The purpose of this study was to assess the acute psychoactive and physiological properties of 5-HT( 3) antagonism using ondansetron as a probe. Ondansetron is used clinically as an anti-emetic but is also under treatment consideration for a range of psychiatric disorders including drug abuse. A 15 min infusion of 40 mg ondansetron, a 1 min infusion of 25 mg of cocaine (positive control) and their respective placebos were tested intravenously in eight volunteers with histories of drug abuse in a blinded cross-over study. Ondansetron responses could not be distinguished from the placebo. Cocaine produced typical subjective and physiological effects. These findings indicate that the prototypic 5-HT( 3) receptor antagonist ondansetron does not produce acute psychoactive effects when infused at doses of up to 40 mg and has no rewarding effects with this regime.

A method for immunoisolation of sporocysts of Schistosoma mansoni in nonsusceptible snails

A technique is described for immunoisolation of sporocysts of Schistosoma mansoni in nonsusceptible Biomphalaria glabrata by microencapsulation in agarose. Based on histological evidence, all 11 microencapsulated sporocysts implanted into 3 schistosome-resistant 13-16-R1 snails were alive at 72 hr postimplantation, although in a developmentally retarded condition. However, among 146 sporocysts derived from miracidia that had penetrated 5 snails, 96% were dead by 72 hr. These results suggest that hemocyte contact is necessary for rapid sporocyst death in vivo.

Genomic analysis of a transposition-deletion variant of orf virus reveals a 3.3 kbp region of non-essential DNA

Restriction endonuclease analysis of the DNA extracted orf virus strain NZ2, which had been serially passaged in primary bovine testis cells, revealed a population of variants that had over-grown the wild-type virus. At least three distinct mutant forms were identified in which the right end of the genome had been duplicated and translocated to the left end, accompanied by deletions of sequences at the left end. Sequencing of a single variant isolated from the heterogeneous population revealed that recombination had occurred between non-homologous sequences. In this case, 6.6 kb of DNA at the left end of the genome had been replaced by 19.3 kb from the right end. The transposition resulted in the deletion at the left end of 3.3 kb of DNA encoding three genes and the terminal sequences of a fourth gene. The three genes completely deleted were a homologue of dUTPase, a gene that encodes a protein containing ankyrin-like repeats and a homologue of the 5K gene of the vaccinia virus WR strain. Experimental inoculation of sheep showed that the genes are also non-essential in vivo, but that the size of the lesion was reduced, compared with that induced by the wild-type, and resolved more rapidly.

Killing of Schistosoma mansoni sporocysts in Biomphalaria glabrata implanted with amoebocyte-producing organ allografts from resistant snails

Schistosome-susceptible National Institutes of Health (NIH) albino Biomphalaria glabrata were implanted with the amoebocyte-producing organ (APO) from 4 types of donors: (1) exposed-resistant (eR), i.e., schistosome-resistant 13-16-R1 snails that had been exposed to miracidia of Schistosoma mansoni 30 or more days previously in order to verify their resistance, (2) exposed-susceptible (eS), i.e., NIH albino snails that had been similarly exposed to miracidia, (3) unexposed-resistant (uR), and (4) unexposed-susceptible (uS). Allograft recipients, along with unimplanted NIH albino and 13-16-R1 controls (cS and cR, respectively), were then challenged with 100 miracidia each of Schistosoma mansoni at 14-15 days postimplantation. Histological sections of tentacles fixed at 3 days postchallenge (PC) showed significantly fewer normal sporocysts and more numerous developmentally retarded sporocysts in cR snails than in the other 5 treatment groups, and significantly more killed sporocysts in both cR snails and recipients of eR APOs than in the other 4 groups. In addition, the histological condition of eR allografts in both unchallenged (at 1, 3, 7, 10, and 14 days postimplantation) and schistosome-challenged (at 3 days PC) NIH albino recipients was examined. Viable hematopoietic cells were found in 96% of implants, and in 86% of implants low numbers of mitotic figures were found among these cells, although no increased mitotic activity occurred in challenged recipients. These data suggest that lowered susceptibility to infection with S. mansoni in recipients of APO allografts results primarily from hemocyte-mediated resistance.

The establishment of a genetic map of orf virus reveals a pattern of genomic organization that is highly conserved among divergent poxviruses

The large differences between the G+C content of the orf virus genome and those of other characterized poxviruses have precluded the use of DNA hybridization to establish a gene map of orf virus. Here we have sequenced the ends of cloned restriction endonuclease fragments of the nZ2 strain of orf virus (OV) and used the translated sequences to search protein data bases. Sequence from 15 points found high-scoring matches to data base entries, including 18 vaccinia virus (VAC) genes. We also present 2 kb of sequence from a region near the right terminus of the OV genome and show that it encodes homologs of VAC genes, F9L and F10L. The data presented here in conjunction with published and as yet unpublished data have allowed the construction of a gene map of OV on which 37 genes have been placed. Thirty-two of these genes have homologs in VAC. Alignment of the OV gene map with that of VAC revealed that each OV gene and its VAC counterpart occurred in the same order and orientation on their respective genomes. The intervals between many of the points of sequence were also found to be strikingly similar. The conserved spacing of genes between OV and VAC within the central 88.2 kb of the 139-kb OV genome is not maintained in the termini where insertion, deletion, and translocation have occurred. Parallels are drawn between the data presented here and related data from swinepox virus and capripox virus.

Nodulating strains of Rhizobium loti arise through chromosomal symbiotic gene transfer in the environment

Rhizobia were isolated from nodules off a stand of Lotus corniculatus established with a single inoculant strain, ICMP3153, 7 years earlier in an area devoid of naturalized Rhizobium loti. The isolates showed diversity in growth rate, Spe I fingerprint of genomic DNA, and hybridization pattern to genomic DNA probes. The 19% of isolates that grew at the same rate as strain ICMP3153 were the only isolates that had the same fingerprint as strain ICMP3153. Sequencing of part of the 16S rRNA gene of several diverse isolates confirmed that they were not derived from the inoculant strain. Nevertheless, all non-ICMP3153 strains gave EcoRI and Spe I hybridization patterns identical to ICMP3153 when hybridized to nodulation gene cosmids. Hybridization of digests generated by the very rare cutting enzyme Swa I revealed that the symbiotic DNA region (at least 105 kb) was chromosomally integrated in the strains. The results suggest that the diverse strains arose by transfer of chromosomal symbiotic genes from ICMP3153 to nonsymbiotic rhizobia in the environment.

Intravenous caffeine in stimulant drug abusers: subjective reports and physiological effects

The present study was conducted to examine the self-reported (i.e., subjective) and physiological effects of intravenous caffeine in 10 subjects with histories of stimulant drug abuse. Under double-blind conditions, subjects received each dose of caffeine (0, 37.5, 75, 150 or 300 mg/70 kg) twice according to a latin-square design; injections were 10 sec in duration and separated by at least 24 hr. Effects were measured before injection and repeatedly afterward for 60 min. Caffeine dose-dependently increased ratings of positive mood (e.g., increased ratings of drug liking and high), which peaked at 2 min after injection and progressively decreased. Caffeine also dose-dependently increased the frequency of stimulant identifications on the Pharmacological Class Identification Questionnaire (e.g., like cocaine, amphetamine). Caffeine also produced negative-mood effects (e.g., increased ratings of bad effects) and increases in self-reported desire for cocaine. In contrast to the positive-mood effects, the negative-mood effects were of smaller magnitude and only significant at the highest dose. Caffeine increased reports of unusual smells and tastes. Caffeine decreased heart rate (7 bpm) and skin temperature (4 degrees C), and increased systolic and diastolic blood pressures (8 and 6 mm Hg, respectively). The mood effects but not the physiological effects of intravenous caffeine were similar to those previously observed with cocaine in studies using similar methods and subjects. Intravenous caffeine administration may provide a useful model system for investigating factors relevant to the use and abuse of stimulant drugs.

Sequence and transcriptional analysis of a near-terminal region of the orf virus genome

A 3605 bp region located approximately 6.6 kb from the left end of the orf virus genome (strain NZ2) was sequenced. The sequence revealed two open reading frames, which we have designated G2L and B1L. The predicted amino acid sequences of G2L and B1L were found to be homologous to the vaccinia virus (VAC) F11L and F12L gene products, respectively, and were found to be arranged on the genome in the same orientation and relative position as their VAC counterparts. Transcriptional analysis of both G2L and B1L showed they were transcribed toward the genome terminus during the early phase of infection. S1 nuclease and primer-extension analyses showed that the transcriptional start sites of both genes were located a short distance downstream from A+T-rich sequences, similar to vac virus early promoters.

Sequence and transcriptional analysis of an orf virus gene encoding ankyrin-like repeat sequences

A 1608 bp region located approximately 5.0 kb from the left end of the orf virus (OV) genome (strain NZ2) was sequenced. The sequence revealed a single open reading frame designated G1L. The predicted amino acid sequence of G1L contained eight ankyrinlike repeat sequences. Transcriptional analysis of G1L showed it was transcribed towards the genome terminus during the early phase of infection. S1 nuclease and primer extension analyses showed that the transcriptional start site of the gene was located a short distance downstream from an A + T-rich sequence similar to a vaccinia virus early promoter.

Fluoxetine alters the effects of intravenous cocaine in humans

Fluoxetine, a selective serotonin reuptake inhibitor, is currently being evaluated as a potential treatment for cocaine abuse. This 4-week inpatient study evaluated the pharmacologic interaction between fluoxetine and cocaine in healthy adult male volunteers (N = 5) with histories of cocaine abuse. Oral capsules were administered daily containing either placebo (weeks 1 and 4) or fluoxetine in a series of ascending doses (10, 20, 30, and 40 mg) where each dose was given for three to four consecutive days. Cocaine challenge sessions were conducted twice weekly, once at each active dose level and twice during both the placebo and washout phases. Subjects received three ascending intravenous doses of cocaine (0, 20, and 40 mg) 1.5 hours apart and were monitored on physiologic and subjective measures. Cocaine alone increased heart rate, blood pressure, and pupillary diameter and increased subjective reports reflecting positive mood effects and drug liking. Fluoxetine (40 mg) significantly decreased subjective ratings of cocaine's positive mood effects on several visual analog measures. Fluoxetine also attenuated the mydriatic effect of cocaine. No adverse physiologic interactions between the two drugs were observed on cardiovascular measures. These data suggest that fluoxetine may be safely used in the presence of cocaine use and should be investigated further as a potential pharmacotherapy for cocaine abuse.

Identification and characterization of an orf virus homologue of the vaccinia virus gene encoding the major envelope antigen p37K

DNA sequence analysis of a 1.55-kb region located 10 kb from the left end of the orf virus NZ-2 strain (OV NZ2) genome revealed an open reading frame, B2L, encoding a protein with a predicted molecular weight of 41.67 kDa. This protein (p42K) shows 42% amino acid sequence identity to the vaccinia virus (VAC) major envelope antigen p37K. In addition, p42K shows homology to a protein encoded by molluscum contagiosum virus (42.8% identity) and another encoded by fowlpox virus (38.3% identity). These proteins are themselves homologues of the VAC p37K. B2L is actively transcribed after the onset of DNA replication and S1 nuclease analysis mapped the 5' end of the transcript to within the sequence TAAATG. A VAC recombinant capable of expressing the p42K gene was constructed and used as an antigen in radioimmune precipitations and lymphocyte transformation assays. These assays demonstrated that OV p42K is one of a limited number of OV proteins to which sheep mount a strong antibody response and which stimulate lymphocytes derived from draining lymph nodes following a natural infection with OV NZ2.

Transfer of resistance to Schistosoma mansoni in Biomphalaria glabrata by allografts of amoebocyte-producing organ

Allografts of amoebocyte-producing organ (APO) were implanted heterotopically into the schistosome-susceptible NIH albino stock of Biomphalaria glabrata from either 13-16-R1 (a schistosome-resistant stock) or NIH albino donors. At 3, 7-8, 14-15, 21, 28-33, or 47-71 days postimplantation (PI), allograft recipients were exposed to 50 miracidia each of Schistosoma mansoni and subsequently monitored for development of sporocysts and cercariae. Relative to untampered snails and recipients of NIH albino APOs, recipients of 13-16-R1 APOs showed significantly lower infection rates from 7 days PI until the end of the experiment. The mechanism for this apparent transfer of resistance is unknown, but hypothetically it may involve chimerism, i.e., production of hemocytes with the resistant phenotype by implanted 13-16-R1 APOs, or synthesis by the implant of soluble "resistance factors" that induce cytotoxicity in recipient hemocytes, or both.

Psychopharmacology and abuse potential of transnasal butorphanol

The effects of butorphanol administered by a nasal spray (transnasal, TN) and by intramuscular (IM) injection were compared to determine the onset of action, relative potency, profile of effects, and relative abuse liability of TN butorphanol. TN/IM placebo and TN and IM butorphanol (1, 2, and 4 mg) were tested in seven male opioid abusers not currently physically dependent on opioids using a double-blind, double-dummy, Latin square design. Measures of subjective, behavioral and physiological response were assessed. The onset and duration of action of butorphanol administered by the IM and TN routes were similar at low doses, but onset of TN butorphanol 4 mg was slower than that of 4 mg IM. IM butorphanol produced miosis, some opiate-like behavioral and subjective effects, and increasing dysphoric sedation and perceptual effects with increasing dose. TN and IM butorphanol 1 and 2 mg produced effects that were qualitatively and quantitatively similar; however, TN butorphanol 4 mg was less potent than 4 mg IM. Pharmacodynamic evidence suggests that the abuse potential of TN butorphanol is not different from that of IM butorphanol.

Single-dose pharmacodynamics of diazepam and pentobarbital in substance abusers

The likelihood that a given drug will be misused is related to its ability to alter mood, feeling, thinking, and perception in a manner that is liked by substance abusers. The subjective and behavioral effects of diazepam (10, 20, and 40 mg), pentobarbital (120 and 240 mg as a positive control), and placebo (negative control), were evaluated in 12 subjects with histories of substance abuse by use of a double-blind, Latin square crossover study design. Drug administration was separated by a minimum of 3 days. Pharmacodynamic measures included subjective (euphoria, subject liking, sedation, and symptoms) and behavioral (signs and observed liking) responses. The time course and profile of subjective and behavioral responses were similar for diazepam and pentobarbital. Valid relative potency estimates for the pharmacodynamic measures indicated that diazepam is approximately 10 times as potent as pentobarbital. The study indicates that the reinforcing effects of diazepam are similar to pentobarbital in substance abusers.

Heterotopic heart transplants in Biomphalaria glabrata (Mollusca: Pulmonata). Fate of congeneric xenografts

Hearts were implanted heterotopically into the hemocoel of NIH albino Biomphalaria glabrata from three xenogeneic donor snails, including two New World (B. obstructa, B. tenagophila) and one Old World (B. alexandrina) species, as well as from wild type allogeneic donors. Recipients were examined histologically at 1, 3, 7, 10, 15, 30, 60, 120, and 180 days postimplantation (PI). Grafts from all four donor species were temporarily infiltrated by recipient hemocytes at early intervals PI and in most instances also became encapsulated. Furthermore, the grafts subsequently showed histopathological alterations and abnormal heartbeat relative to preimplantation controls. However, hemocytic reactions eventually subsided, the implants remained structurally intact, and implant myocardial cells both maintained high levels of intracellular glycogen and continued to contract rhythmically for 6 months. No major differences occurred in fates among different xenografts, or between xenografts and allografts. Our observations of prolonged xenograft survival differ from those of previous investigators, most of whom have reported rapid destruction of implanted xenogeneic tissues in molluscs.

Effects of cocaine alone and in combination with mazindol in human cocaine abusers

Mazindol is a catecholamine reuptake inhibitor that blocks binding of cocaine at the dopamine reuptake site. This study was conducted to determine whether the acute administration of mazindol modulates the pharmacological effects of intravenous cocaine in humans. In a crossover study, twelve acute drug conditions were tested in randomized order under double-blind, double-dummy conditions in eight cocaine abusers. Cocaine (0, 12.5, 25 and 50 mg, i.v.) was administered in combination with mazindol (0, 1 and 2 mg given orally 2 hr before the cocaine injection). Physiological and subject- and observer-rated responses were measured. Cocaine and mazindol alone both significantly increased heart rate and blood pressure. Cocaine increased ratings on stimulant-like subjective effect measures, including desire for cocaine; mazindol had mild, stimulant-like subjective effects. There were significant interactions between the effects of cocaine and mazindol on heart rate and blood pressure, with combinations producing significantly large and more sustained increases compared with cocaine alone. There was no evidence that mazindol substantially altered the magnitude or profile of the subjective effects of cocaine, including cocaine-induced craving for cocaine. These results do not support the utility of acute administration of mazindol in the treatment of cocaine abusers through a mechanism of modulation of cocaine's subjective effects. Furthermore, mazindol treatment may increase the cardiovascular risks of cocaine.

Prevalence of hepatitis C in a chemically dependent population

BACKGROUND

Drug abuse is the major risk factor for hepatitis C in the United States. The objective of this study was to determine the prevalence of hepatitis C virus (HCV), to identify risk factors for HCV, and to correlate HCV and liver function in patients presenting for inpatient detoxification of substances of abuse.

METHODS

A total of 687 patients were tested for the presence of antibody to HCV (anti-HCV). Histories related to drug use, sexually transmitted diseases, blood transfusion, and human immunodeficiency virus were obtained, as were serum tests for human immunodeficiency virus, syphilis, hepatitis B, aminotransferases, total bilirubin, and alkaline phosphatase.

RESULTS

The overall prevalence of anti-HCV was 63%: 68% in men vs 54% in women (P < .001), with no difference by race. Remarkably, 86% of injecting drug users tested positive for anti-HCV. Identified risk factors for anti-HCV were injecting drug use (P < .001), human immunodeficiency virus infection (P = .003), exposure to hepatitis B virus (P < .001), and a positive rapid plasma reagin test (P = .04). Previous transfusion and history of previous infection with gonorrhea or syphilis did not correlate with the presence of anti-HCV. Patients positive for anti-HCV had significant elevations in aspartate aminotransferase and alanine aminotransferase levels when compared with patients negative for anti-HCV: 50.8 vs 36.7 U/L (P = .002) and 56.0 vs 36.9 U/L (P < .001), respectively.

CONCLUSION

Injecting drug users have an extremely high prevalence of anti-HCV. This is the first demonstration, to our knowledge, that the presence of anti-HCV in drug users is associated with significantly increased levels of serum aminotransferases.

Effects of Schistosoma mansoni infection on phagocytosis and killing of Proteus vulgaris in Biomphalaria glabrata hemocytes

With the use of a fluorescence microassay, in vitro phagocytosis and killing of Proteus vulgaris were measured in hemocytes of NIH albino Biomphalaria glabrata infected with Schistosoma mansoni for 1, 2, 3, or 4 wk. Although hemocytes of infected snails displayed decreased phagocytosis, relative to hemocytes of uninfected snails, at 4 wk postinfection (PI), they exhibited enhanced microbicidal activity at 3 wk PI. No microbicidal activity was detected in the plasma of either infected or uninfected snails.

Pneumothorax in polysubstance-abusing marijuana and tobacco smokers: three cases

Three patients are reported who suffered spontaneous pneumothorax, each of whom also had a history of daily marijuana and tobacco use. The patients ranged in age from 24 to 37 years, had smoked marijuana on a daily basis for 10 to 14 years, and had 11 to 50 pack-year tobacco-smoking histories. Marijuana may predispose to pneumothorax both by accelerating tobacco-induced lung disease, and by the frequent performance of the Valsalva maneuver during marijuana smoking. Although there is an association between pneumothorax and heavy tobacco use, an association with chronic daily marijuana use has not previously been reported.

Psychoactivity and abuse potential of sumatriptan

Sumatriptan is a 5-HT1D agonist of therapeutic use in migraine and cluster headaches. To determine the profile of psychoactivity and abuse potential, a double-blind Latin-square crossover study was conducted in 12 male subjects with histories of substance abuse. The effects of subcutaneous placebo, sumatriptan (8 and 16 mg), and morphine (10 and 20 mg) were assessed on measures of subjective, behavioral, and physiologic responses including signs, symptoms, Addiction Research Center Inventory scales, onset of drug effects and miosis. Sumatriptan was psychoactive, was discriminated from placebo, produced a dose-related decrease on euphoria scores, elevated scores on measures of apathetic sedation and disliking, and lacked identification as a prototypic drug of abuse. There were no clinically significant effects on heart rate, pupil size, or blood pressure. In contrast, morphine (the positive control) produced expected dose-response relationships on measures of reinforcing and physiologic effects. The study suggests that sumatriptan has a low abuse potential.