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Gasotrasmitters are endogenously synthesized gaseous molecules that are engaged in cellular physiological and pathological processes. Stress influences various physiological aspects of an organism and amends a normal system's functions, including those of the reproductive system. This study aims to investigate the effect of long-term exposure to restraint stress on the male reproductive system as well as the possible impact of stress on the levels of nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H 2 S), and the expression of their producing-enzymes. In this study, rats were subjected to the restraint condition for 2 h per day and 7 days per week for 8 consecutive weeks. The results revealed decreases in the serum levels of kisspeptin-1(Kiss-1), gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and dehydroepiandrosterone sulfate (DHEA-s); however, corticosterone, gonadotropin-inhibitory hormone (GnIH), estradiol (E2) and prolactin levels increased following restraint stress. The mRNA expression levels of NO synthases (NOSs); neuronal NOS (nNOS), inducible NOS (iNOS) and H 2 S synthases; cystathionine-γ-lyase- (CSE), 3-mercaptopyruvate-sulfurtransferase- (3MST) and CO-producing enzyme; heme oxygenase-2 (HO-2) were upregulated in the hypothalamus of restraint rats. Testicular mRNA expression levels of endothelial NOS (eNOS), nNOS, HO-1 and HO-2 were upregulated whereas cystathionine β-synthase (CBS), CSE and 3MST expression levels were downregulated following restraint stress. Concentrations of NO increased in the testes but decreased in the semen of restraint rats. On the contrary, CO levels were reduced in the testes while they were elevated in the semen, whereas H 2 S concentrations decreased in both testes and semen of restraint rats. Concentrations of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), as well as total antioxidant capacity (TAC) rose in the testes, while they declined in the semen of the restraint group. Restraint stress decreases the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the testes while increasing them in the semen. Collectively, restraint stress negatively impacts male reproductive functions and modulates gasotransmitters producing-enzymes expression in the hypothalamus and testes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: We examine the ability of pre-existing measures of Forced Expiratory Volume in 1 s (FEV1), and Diffusion Capacity for Carbon Monoxide (DLCO) to determine the subsequent 30-day mortality outcome following unselected acute medical admission., Methods: Between 2002 and 2017, we studied all emergency medical admissions (106,586 episodes in 54,928 patients) of whom 8071 were classified as respiratory. We employed logisitic multiple variable regression models to evaluate the ability of FEV1 or DLCO to predict the 30-day hospital mortality outcome., Results: The 30-day hospital episode mortality outcome demonstrated curvilinear relationships to the underlying FEV1 or DLCO values; adjusted for major outcome predictors, a higher FEV1 - OR 0.85 (95% CI: 0.82, 0.89) or DLCO OR 0.76 (95% CI: 0.73, 0.79) values predicted survival. The range of predicted mortalities was from 3.3% (95% CI: 2.5, 4.0) to 23.5% (95% CI: 20.8, 26.2); the FEV1 (Model1) and DLCO (Model2) outcome prediction was essentially equivalent (Chi2 = 2.9: p = 0.08)., Conclusion: The 30-day mortality outcome was clearly related to the pre-admission FEV1 and DLCO value. The outcome relationship was curvilinear. Either parameter appears a useful tool to explore hospital outcomes. Previously suggested cut-points are likely an artefact and not supported by these data., (Copyright © 2018 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

We evaluated the intra-session and inter-session variability of the diffusing capacity of nitric oxide (DLNO), carbon monoxide (DLCO), alveolar-capillary membrane diffusing capacity for carbon monoxide (DMCO) and pulmonary capillary blood volume (Vc) in patients with cystic fibrosis (CF). Patients performed single-breath diffusing capacity measurements during all of 3 consecutive study visits. Precision of gas diffusing parameters was quantified by within-subject standard deviation (SD ws ) and coefficient of variation (CV). Intra-session and inter-session reproducibility was determined by SD ws *2.77. 15 clinically stable patients were included. The intra-session precision of gas diffusing parameters improved over the study visits. The inter-session SD ws for DLNO, DLCO, DMCO, and Vc was 4.8, 1.3, 2.4, and 4.3, respectively. Reproducibility was 13.3, 3.8, 6.7 and 12.0mLmin -1 mmHg -1 ; CV was 4.4, 4.7, 4.4 and 5.8%, respectively. The intra-session variability of DLNO, DLCO, DMCO and Vc improves with breath-hold maneuver training in test-naïve patients with CF, indicating a learning effect. Inter-session reproducibility data are lower than those previously reported in healthy subjects., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Roughton and Forster (RF) proposed to split the lung diffusing capacity into two contributions describing first, diffusion to red blood cells (RBC), and second, capture by diffusion from the RBC surface and reaction with haemoglobin. Solving the diffusion-reaction equations for simplified capillary-RBC structures, we investigate the RF interpretation. This reveals first that the conventional extrapolation to zero pressure of 1/DLCO on PO 2 is not a correct measure of the diffusive component. Consequently the capillary volumes deduced from this extrapolation are erroneous. Secondly, capture mechanisms are different for CO and NO: while DLCO characterizes "volume absorption" in the RBC and is correlated with hematocrit, DLNO quantifies "surface absorption" and provide information about the morphology of the space between the alveolar surface and the RBC surfaces. In conclusion, the RF approach may lead to erroneous physiological interpretations of DLCO; nevertheless, the measurement of DLCO and DLNO bring different types of information that give the potential for a better understanding of respiratory diseases., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

Nitric oxide was introduced over 30 years ago as a test gas for alveolar capillary diffusion. As for CO its transfer has been interpreted according to the Roughton Forster relationship: 1/DL=1/DM+1/θVc. There has been disagreement, since the first measurements of DLNO, over whether θ NO is infinite and thus DLNO=DMNO. There is overwhelming in vitro evidence that θ NO is finite yet several groups (Coffman et al., 2017; Tamhane et al., 2001) use an infinite value in vivo. They also assume that DMNO is greater than twice DMCO, making DMCO less than that predicted by the physical laws of diffusion. Finally some (Coffman et al., 2017) recommend use of Reeve and Park's value for θ CO (Reeves and Park, 1992; Coffman et al., 2017) rather than Forster's (Forster, 1987). Their grounds for doing so are that the combination of an infinite theta NO, an empirical value for DMNO/DMCO (>2.0) and Reeve and Park's θ CO gives a value of DMCO (using a combined DLNO-DLCO analysis) which agrees with the DMCO value calculated separately by the classical two-stage oxygen technique of Roughton and Forster. In this paper we examine whether there are physiological reasons for assuming that DMNO is over twice DMCO in vivo. We are critical of Reeves and Park's estimate for the 1/θ CO -PO 2 relationship. We review in vitro estimates of θ CO in the light of Guenard et al.'s recent in vivo estimate., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Membrane conductance (Dm) and capillary lung volume (Vc) derived from NO and CO lung transfer measurements in humans depend on the blood conductance (θ) values of both gases. Many θ values have been proposed in the literature. In the present study, measurements of CO and NO transfer while breathing 15% or 21% O2 allowed the estimation of θNO and the calculation of the optimal equation relating 1/θCO to pulmonary capillary oxygen pressure (PcapO2). In 10 healthy subjects, the mean calculated θNO value was similar to the θNO value previously reported in the literature (4.5mmHgmin(-1)) provided that one among three θCO equations from the literature was chosen. Setting 1/θCO=a·PcapO2+b, optimal values of a and b could be chosen using two methods: 1) by minimizing the difference between Dm/Vc ratios for any PcapO2, 2) by establishing a linear equation relating a and b. Using these methods, we are proposing the equation 1/θCO=0.0062·PcapO2+1.16, which is similar to two equations previously reported in the literature. With this set of θ values, DmCO reached the morphometric range., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Lung function abnormalities occur in children with sickle cell disease (SCD) and may be associated with elevated pulmonary blood volume. To investigate that association, we determined whether blood transfusion in SCD children acutely increased pulmonary capillary blood volume (PCBV) and increased respiratory system resistance (Rrs5). Measurements of Rrs5 and spirometry were made before and after blood transfusion in 18 children, median age 14.2 (6.6-18.5) years. Diffusing capacity for carbon monoxide and nitric oxide were assessed to calculate the PCBV. Post transfusion, the median Rrs5 had increased from 127.4 to 141.3% predicted (p<0.0001) and pulmonary capillary blood volume from 39.7 to 64.1 ml/m2 (p<0.0001); forced expiratory volume in one second (p=0.0056) and vital capacity (p=0.0008) decreased. The increase in Rrs5 correlated with the increase in PCBV (r=0.50, p=0.0493). Increased pulmonary capillary blood volume may at least partially explain the lung function abnormalities in SCD children., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Alveolar-capillary membrane conductance (D(M,CO)) and pulmonary-capillary blood volume (V(C)) are calculated via lung diffusing capacity for carbon monoxide (DL(CO)) and nitric oxide (DL(NO)) using the single breath, single oxygen tension (single-FiO2) method. However, two calculation parameters, the reaction rate of carbon monoxide with blood (θ(CO)) and the D(M,NO)/D(M,CO) ratio (α-ratio), are controversial. This study systematically determined optimal θ(CO) and α-ratio values to be used in the single-FiO2 method that yielded the most similar D(M,CO) and V(C) values compared to the 'gold-standard' multiple-FiO2 method. Eleven healthy subjects performed single breath DL(CO)/DL(NO) maneuvers at rest and during exercise. D(M,CO) and V(C) were calculated via the single-FiO2 and multiple-FiO2 methods by implementing seven θ(CO) equations and a range of previously reported α-ratios. The RP θ(CO) equation (Reeves, R.B., Park, H.K., 1992. Respiration Physiology 88 1-21) and an α-ratio of 4.0-4.4 yielded DM,CO and VC values that were most similar between methods. The RP θ(CO) equation and an experimental α-ratio should be used in future studies., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Homeless adults are exposed to more smokers and smoke in response to environmental tobacco cues more than other socioeconomically disadvantaged groups. Addressing the culture of smoking in homeless shelters through policy initiatives may support cessation and improve health in this vulnerable and understudied population. This study examined support for and expected/actual effects of a smoking ban at a homeless shelter. A 2-wave cross-sectional study with an embedded cohort was conducted in the summer of 2013 two weeks before (wave 1) and two months after (wave 2) a partial outdoor smoking ban was implemented. A total of 394 homeless adults were surveyed (i.e., wave 1 [n=155]; wave 2 [n=150]; and 89 additional participants completed both waves). On average, participants were 43 years old, primarily African American (63%), male (72%), and had been homeless for the previous 12 months (median). Most participants were smokers (76%) smoking 12 cigarettes per day on average. Most participants supported the creation of a large smoke-free zone on the shelter campus, but there was less support for a shelter-wide smoking ban. Average cigarettes smoked per day did not differ between study waves. However, participants who completed both study waves experienced a reduction in expired carbon monoxide at wave 2 (W1=18.2 vs. W2=15.8 parts per million, p=.02). Expected effects of the partial ban were similar to actual effects. Partial outdoor smoking bans may be well supported by homeless shelter residents and may have a positive impact on shelter resident health., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: Previous studies have demonstrated an important role for beta-2 adrenergic receptors (β(2)AR) in lung fluid clearance. The purpose of this investigation was to examine the relationship between β(2)AR density on lymphocytes and indices of lung water in healthy humans exposed to ≈ 17 h of hypoxia (FIO2 = 12.5% in a hypoxia tent)., Methods: Thirteen adults (mean ± SEM; age=31 ± 3 years, BMI=24 ± 1 kg/m(2), VO2 Peak = 40 ± 2 ml/kg/min ) participated. Pulmonary function, CT derived lung tissue volume (V(tis)-tissue, blood and water), lung diffusing capacity for carbon monoxide (D(CO)) and nitric oxide (D(NO)), alveolar-capillary conductance (D(M)), pulmonary capillary blood volume (V(c)) and lung water (CT V(tis)-V(c)) were assessed before and after ≈ 17 h normobaric hypoxia (FIO2 = 12.5%). β(2)AR density on lymphocytes was measured via radioligand binding. Arterial oxygen saturation (SaO2), cardiac output (Q), right ventricular systolic pressure (RVSP) and blood pressure (BP) were also assessed., Results: After 17 h hypoxia, SaO2 decreased from 97 ± 1 (normoxia) to 82 ± 4% and RVSP increased from 14 ± 3 (normoxia) to 29 ± 2 mmHg (p<0.05) with little change in Q or BP. V(c) and D(M) both increased with hypoxia with a small increase in D(M)/V(c) ratio (p>0.05). CT V(tis) decreased and lung water was estimated to decline 7 ± 13%, respectively. β(2)AR density averaged 1497 ± 187 receptors/lymphocyte and increased 21 ± 34% with hypoxia (range -31 to +86%). The post-hypoxia increase in β(2)AR density was significantly related to the reduction in lung water (r=-0.64, p<0.05), with the subjects with the greatest increase in density demonstrating the largest decline in lung water., Conclusions: Lung water decreases with 17 h normobaric hypoxia are associated with changes in beta adrenergic receptor density on lymphocytes in healthy adults., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background and Aims: Experimental data suggest that in liver cirrhosis splanchnic and systemic vasculature exhibit marked endothelial Carbon monoxide (CO) overproduction, while recent data demonstrated heme oxygenase (HO) hyperactivity in the liver of rats with cirrhosis. No data are so far available on CO levels in the hepatic veins of cirrhotic patients. We aimed at evaluating whether plasma CO levels differ between systemic (peripheral vein) and hepatic (hepatic vein) circulation in patients with viral cirrhosis with and without ascites., Methods: We enrolled 31 consecutive non-smoking in- or outpatients with liver cirrhosis. We measured wedge (occluded, WHVP) and free hepatic venous pressures (FHVP) and hepatic-vein pressure gradient (HVPG) was the calculated. Plasma level of NO and plasma CO concentration were determined both in peripheral vein and in the hepatic vein in cirrhotics., Results: In cirrhotic patients plasma CO levels were significantly higher in the hepatic vein (16.66±10.71 p.p.m.) than in the peripheral vein (11.71±7.00 p.p.m). Plasma NO levels were significantly higher in peripheral vein (97.02±21.11 μmol/ml) than in the hepatic vein (60.76±22.93 μmol/ml)., Conclusions: In patients with liver cirrhosis we documented a hepato-systemic CO gradient as inferred by the higher CO values in the hepatic vein than in the peripheral vein. In cirrhotic patients, CO and NO exhibit opposite behavior in the liver, while both molecules show increased values in the systemic circulation. It can be speculated that increased intra-hepatic CO levels might represent a counterbalancing response to reduced NO intra-hepatic levels in human liver cirrhosis., (Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

Background: The degree of arterial hypoxemia during air travel in individuals with obstructive sleep apnea (OSA) is not known. The Aerospace Medical Association considers a ground level arterial oxygen tension (PaO₂) above 9.3 kPa as safe before air travel., Methods: Fifteen subjects with untreated OSA (mean apnea-hypopnea index [AHI] 43/h) and 14 with treated OSA (mean AHI on CPAP 1.9/h) completed an assessment including hypoxic challenge test (HCT). The groups had similar mean age, mean BMI and pre-treatment OSA severity., Results: Four subjects, all in the untreated group and with resting PaO₂ >9.3 kPa and oxygen saturation (SpO₂) >95%, had a positive HCT (PaO₂ <6.6 kPa and/or SpO₂ <85%). The PaO₂ at the end of the HCT was significantly correlated with the minimum overnight SpO₂ (r=.754, p=.002) but not with the daytime PaO₂ and SpO₂. Using a cut off value of 65%, the minimum overnight SpO₂ had positive and negative predictive values of 57% and 100% respectively., Conclusions: OSA can be an additional risk factor for developing significant arterial hypoxemia during HCT. Baseline PaO₂ and SpO₂ did not predict arterial hypoxemia during the HCT. Minimum overnight SpO₂ <65% may be used as a cut off to advise further assessment. Effective treatment of OSA seems to be the best option before air travel., (Copyright © 2011. Published by Elsevier B.V.)

Objectives: This study examined differences in cessation success based on smokers' self-initiated pre-quit reductions in cigarettes per day (cpd)., Methods: The study utilized data from a nicotine replacement+behavioral therapy smoking cessation intervention conducted in a female prison facility with 179 participants who were wait-listed for 6 months prior to intervention. We compared two groups of smokers based on whether they self-selected to reduce smoking prior to their cessation attempt (n=77) or whether they increased smoking or did not reduce (n=102). General Estimating Equations (GEE) were used to model smoking cessation through 12-month follow-up., Results: Examination of pre-cessation cpd showed that those who reduced were heavier smokers at baseline, relative to those who did not reduce (p<0.001). By the week prior to the quit attempt (week 3) heavier smokers at baseline smoked significantly fewer cigarettes (p<0.001) and had lower CO levels (p<0.05) compared to baseline lighter smokers. GEE analyses showed that individuals who reduced prior to their quit attempt had significantly higher quit rates during early treatment but these gains were not sustained by follow-up points., Conclusions: Participant-initiated pre-cessation smoking reduction may be initially helpful in preparing to quit smoking, or may serve as a marker for participant motivation to quit smoking, but these differences do not sustain over time. More intensive interventions are still needed for successful cessation., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The purpose of this study was to compare the repeatability (2.77 multiplied by the within-subject SD)between two different rebreathing protocols on cardiac output ( ˙Q ), pulmonary diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO), and pulmonary capillary blood volume (Vc). This study compared two bag volume protocols [Fixed Bag Volume (FBV) = bag volume fixed at 60% of forced vital capacity; Dynamic Bag Volume (DBV) = bag volume matched to tidal volume at each stage of exercise].Ten females (age = 27±8 yrs; ˙VO2, (peak)=2.5±0.6 L/min had measurements at rest (12%), 52%, 88%, and 100% of ˙VO2, (peak) on two study days. Neither the slope nor intercept of ˙Q vs. ˙VO2 were different between either bag volume protocols. The slope of DLCO vs. ˙Q was the same but the intercept was higher for the FBV protocol. The bag volume affected the slope and the intercept between DLNO vs. ˙Q (p < 0.05).The mean repeatability was similar between both protocols for ˙Q (2.0 vs. 2.3 L/min) and DLCO (3.8 vs.5.9 mL/min/mmHg), regardless of exercise intensity. Increasing exercise intensity made the measurement error worse for Vc and DLNO (p ≤ 0.06). Measurement error was lower for Vc when using the FBV protocol (p = 0.02). Also, the pattern of bag volume used during rebreathing maneuvers affected the relation between DLNO vs. ˙Q more than it affected DLCO vs. ˙Q , or Vc vs. ˙Q. Additionally, the FBV protocol provided less measurement error for Vc compared to the DBV protocol [corrected]., (Copyright 2010 Elsevier B.V. All rights reserved.)

To determine whether lung transfer factor for carbon monoxide (T(L(CO))) alters during menstrual phase and if steroid hormone levels relate to these changes, T(L(CO)) and T(L(CO)) adjusted for both alveolar volume (T(L)/V(A)) and haemoglobin concentration, were measured at five predefined and hormonally confirmed menstrual phases in 13 women. No difference between phases was observed in T(L(CO)) or adjusted values. Moreover, there was no association between the maximal change in oestradiol, progesterone, or oestradiol:progesterone ratio and the change in T(L(CO)) measured at the same time. When the first five chronological measurements, regardless of the menstrual phase at which they were measured, were analysed, T(L(CO)) changed significantly (p<0.05) with a maximal change between the first and fourth test (-2.69+/-2.53, 95% confidence interval). Although these results indicate that the first in a series of T(L(CO)) measurements may be higher, we found neither menstrual cycle phase nor ovarian hormone-related changes in T(L(CO)), and conclude that its adjustment for menstrual phase may not be necessary.

Cigarette smokers experience airway inflammation and epithelial damage, the mechanisms of which are unknown. One potential cause may be free radicals either in tobacco smoke or produced during persistent inflammation. Inflammation may also be a driving force to cause airway epithelium to undergo changes leading to squamous cell metaplasia. To test whether tobacco smoke-induced inflammation could be reduced by a catalytic antioxidant, manganese(III)meso-tetrakis(N,N'-diethyl-1,3-imidazolium-2-yl) porphyrin (AEOL 10150) was given by intratracheal instillation to rats exposed to filtered air or tobacco smoke. Exposure to tobacco smoke for 2 d or 8 weeks (6 h/d, 3 d/week) significantly increased the number of cells recovered by bronchoalveolar lavage (BAL). AEOL 10150 significantly decreased BAL cell number in tobacco smoke-treated rats. Significant reductions in neutrophils were noted at 2 d and macrophages at 8 weeks. Lymphocytes were significantly reduced by AEOL 10150 at both time points. Squamous cell metaplasia following 8 weeks of tobacco smoke exposure was 12% of the total airway epithelial area in animals exposed to tobacco smoke without AEOL 10150, compared with 2% in animals exposed to tobacco smoke, but treated with AEOL 10150 (p <.05). We conclude that a synthetic catalytic antioxidant decreased the adverse effects of exposure to tobacco smoke.

We reported previously that 7-hydroperoxycholesterols, 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 alpha-OOH and 7 beta-OOH), indicated lipid peroxidation. In the present study, we measured not only 7-hydroperoxycholesterols but also oxysterols (7 alpha- and 7 beta-hydroxycholesterol, 7 alpha-OH, and 7 beta-OH) and 3 beta-hydroxycholest-5-en-7-one (7-keto) in the brains of rats that underwent either a sham operation (control), hypoxia, or CO inhalation (1005 ppm) at 37 degrees C for 90 min followed by 48 h of recovery. The levels of 7-hydroperoxycholesterols, 7 beta-OH, and 7-keto were low in the hypoxia group, while the levels were unaltered in the CO group compared with the controls. Among the three groups of CO inhalation, these levels were high in the hyperthermia group (39 degrees C), and the 7-hydroperoxycholesterols were low in the hypothermia group (32 degrees C), compared with the control group. The blood O(2) saturation was almost normal in the hypothermia group, while it was similarly low in the hyperthermia and normothermia groups. The temperature-dependent lipid peroxidation in the brain after CO inhalation and recovery can not be explained by hypoxia due to CO-hemoglobin formation, but may contribute to the delayed neuronal death following CO inhalation. Hypothermia may be applicable to treat patients after CO inhalation.

Nonsmokers and smokers were compared for olfactory sensitivity to two odors associated with cigarettes: nicotine and menthol. Smokers were tested twice--while nonabstinent, and after 16-20 h of smoking abstinence. Smokers showed a higher olfactory threshold for nicotine than did nonsmokers, but the same threshold for menthol. Furthermore, when the smokers were abstinent, they showed a lower olfactory threshold for nicotine than when they were nonabstinent, but again, the same threshold for menthol. These results suggest a nicotine specific olfactory deficit in smokers that is reduced during abstinence.

Although most cigarette smokers exhibit signs of tobacco dependence, a subset of this population, referred to as tobacco chippers, does not show characteristic signs of dependence. Few studies have attempted to characterize differences between these groups of smokers. The purpose of the present study was to examine smoking topography in chippers (CH) and dependent smokers (DS). Topographical variables including puff number and duration, and intercigarette interval were examined in seven CH and seven DS under both laboratory and naturalistic conditions. Saliva nicotine, cotinine, and thiocyanate, as well as expired air carbon monoxide (CO) levels were also measured. The results indicate that there were no differences in smoking topography between CH and DS, except those that would be expected based on selection criteria. Although there were differences between groups on pre- and postsmoking CO and saliva cotinine levels, there were no differences in change scores from pre- to postsmoking on these measures. Additional studies will need to be done in order to completely characterize differences between CH and DS.

Five cigarette smoking methadone maintenance patients (MMP) participated in a within-subjects (A-B-A-B) study involving repeated application of carbon monoxide (CO)-contingent payments for reductions in smoke intake. To replicate and extend findings from an earlier study in non-drug-abusing smokers (Stitzer & Bigelow, 1982), we used the same contingent reinforcement procedure that involved the delivery of a monetary payment ($5) for CO readings which were 50% or less than the average value of readings obtained during the prior noncontingency period. Although four of the five subjects earned the contingent payment on at least three of the eight occasions, the overall effect of the intervention on CO level was nonsignificant. Daily smoking records revealed significantly lower rates during the first contingency intervention for the group as a whole. Significant correlations between CO and the time interval since smoking prior to CO measurement were found. The rather modest intervention effects suggest that important parameters be considered when designing contingency management procedures to reduce cigarette smoking in this difficult population of drug abusers.

This is an exploratory study of compliance to nicotine chewing gum in a multicomponent group smoking cessation program where usage was optional. Two-thirds (24 out of 36) of the participants across three group sessions complied with the recommendation to use nicotine chewing gum. All subjects received standard instructions. Demographic characteristics (age, sex, site of employment) and smoking variables (number of years smoked, pretreatment number of cigarettes smoked per day, and nicotine dependence) failed to predict compliance, but complaint participants reported significantly greater confidence at their ability to not smoke in various challenging situations as measured by the Smoking Self Efficacy Questionnaire. Those who did comply mostly failed to chew the gum in the way instructed. Reduced craving was cited as the most positive feature of gum use.

The ligand binding properties of the Root effect haemoglobin of the marlin have been investigated in the temperature range 12-35 degrees C. An essentially symmetric displacement of the binding isotherms to higher concentration is observed on raising the temperature. Thermodynamic parameters have been obtained for the equilibrium binding constants, in terms of the two state model for co-operativity. Kinetic measurements indicate chain heterogeneity in both the T and R states. Activation parameters have been obtained for both chains in both quaternary states.

Human cigarette smokers modify the way in which they smoke cigarettes of differing nicotine content, apparently to maintain nicotine exposure at a preferred level. The effects of changing from moderate to high or low nicotine content cigarettes were examined in 11 baboons (superspecies Papio cynocephalus) trained to smoke cigarettes for water rewards. Relative to the moderate nicotine content cigarette, the animals took significantly (p less than .05) more puffs on the high nicotine content cigarette, and the puffs on the high nicotine cigarette were significantly larger in volume. The animals made the same number of puffs, relative to the moderate nicotine content cigarette, on the low nicotine content cigarette, but the volume of the puffs was significantly smaller. The cotinine output in urine varied significantly and was directly related to cigarette nicotine content; cotinine is the primary metabolite of nicotine. Baboons, like people, prefer high nicotine content cigarettes. Nonhuman primates also regulate nicotine exposure by modification of their puffing behavior. These results indicate that the nonhuman primate also can be used as a model for the investigation of the behavioral aspects of cigarette smoking.

In two experiments, the flexibility of puff volume was assessed using instructions and feedback to manipulate volume. Also, the effects of altered puff volume on puff duration, puff peak flow, and carbon monoxide (CO) boost were examined. In the first experiment, subjects were told to take small, medium, and large puffs. Subjects were able to accurately follow the puff size instructions; they took different-size puffs by altering their puff durations. In the second experiment, when puff duration was controlled, subjects were able to follow the puff size instructions by altering the intensity of their puffs. These two experiments demonstrated that a wide range of puff volumes can be generated by instructional control and that volume changes can result either from alterations of puff duration or of puff intensity.

Parameters for the storage and analysis of saliva samples used to measure thiocyanate (SCN) levels among moderate smokers were systematically studied. The variables targeted for study were the temperature of storage (0 to 20 degrees F) and the size of the container (5 ml or 10 ml). Additionally, these same variables were examined, independently under three different temporal delays to laboratory analysis: immediate, 3 days, and 7 days. Results within each of the delay conditions revealed no significant differences in SCN levels and provided support for the reliability of measurement when using these procedures in the study of thiocyanate levels. Self-reported smoking rate and alveolar carbon monoxide (COa) readings of a week prior were found to correlate relatively highly with thiocyanate readings. These findings broaden the support for SCN as a corroborative measure of smoking.

1. Carpet Shark haemoglobin shows co-operative equilibrium CO binding at pH 7.0 (n = 1.8). 2. Flash photolysis shows that the T form of the protein is stabilised at low pH and in the presence of Inositol Hexaphosphate (I.H.P.). 3. At high pH the R form of the protein is stabilised and exhibits kinetic heterogeneity, assigned to different chain reactivities. 4. Stopped flow and flash photolysis under various conditions allows estimates to be made of the association and dissociation rates of CO binding for the two forms of the protein. 5. The functionality of the protein, with regard to CO binding, can be described by a modified two state model.

Self-reports of smoking status and breath tests for carbon monoxide were collected in prenatal outpatients. The breath test for carbon monoxide appeared to be a valid and specific measure of smoking status during pregnancy. Of the 179 patients surveyed, 99 reported they had smoked during the present pregnancy. Nineteen of the smokers reported they had quit during the present pregnancy and 46 reported that they smoked fewer cigarettes than at the beginning of their pregnancy. Most of the quitters and reducers stated that they had stopped or reduced their intake early in pregnancy and for pregnancy-related reasons; however, neither parity, nausea or vomiting, marital status, nor requests of physicians or family were associated with higher rates of smoking cessation or reduction. Most of the pregnant smokers were interested in stopping smoking, but few attended a free treatment program.

Haemodialysis is associated with transient leucopenia, hypoxia and activation of the patient's complement system, mediated by blood-membrane contact. Changes in white blood cell counts, blood gases (PaO2 and PaCO2), carbon monoxide diffusing capacity (DLCO) and complement activation (C3d and C3a) were measured pre-treatment and during dialysis. The degree of complement activation, leucopenia and changes in DLCO were influenced by membrane type; these changes were most marked for cellulosic membranes and were much reduced for synthetic membranes. A significant relationship between the degree of leucopenia and the magnitude of change in DLCO during dialysis was demonstrated.