Recombinant human superoxide dismutase enhances the effect of inhaled nitric oxide in persistent pulmonary hypertension

We investigated the pulmonary vascular effects of superoxide dismutase (SOD) alone and in combination with inhaled nitric oxide (iNO) in newborn lambs with persistent pulmonary hypertension (PPHN) following prenatal ligation of the ductus arteriosus. In in vitro experiments, pretreatment with SOD significantly enhanced vascular relaxation in response to the NO donor S-nitrosyl-acetylpenicillamine (SNAP) in fifth-generation pulmonary arteries isolated from lambs with PPHN. In vivo treatment of fully instrumented newborn lambs with a single intratracheal dose of recombinant human CuZn SOD (rhSOD; 5 mg/kg) produced selective dilation of the pulmonary circulation. Further studies, of the combination of rhSOD and iNO, showed enhancement of the pulmonary vascular effects of iNO after brief periods of inhalation of 5 ppm and 80 ppm NO. We conclude that rhSOD reduces pulmonary vascular resistance and facilitates the action of iNO in a lamb model of PPHN. This suggests that rhSOD may prove to be an effective adjunctive treatment for newborns with PPHN.

The paradoxes ofMTBE

A widely used gasoline additive, methyl tertiary butyl ether (MTBE), has been controversial, in part because of concerns about potential inhalation health effects and more recently because of added concerns about water contamination. Although many of the issues related to MTBE have not been fully resolved, several apparent paradoxes can be discerned, including the fact that something intended to improve air quality is now seen as a threat to water quality. Among the lessons that can be derived from the MTBE experience is the value of a comprehensive understanding of the potential risk-benefit tradeoffs of different fuels and fuel additives.

A double-blind, randomized, prospective evaluation of the efficacy and safety of risperidone versus haloperidol in the treatment of schizoaffective disorder

The relative efficacy and safety of risperidone versus haloperidol in the treatment of schizoaffective disorder was studied. Sixty-two patients (29 depressed type; 33 bipolar type) entered a three-site, randomized, double-blind, 6-week trial of risperidone (up to 10 mg/day) or haloperidol (up to 20 mg/day). Trained raters assessed baseline, weekly, and end-of-study levels of psychopathology with the Positive and Negative Syndrome Scale (PANSS), the 24-item Hamilton Rating Scale for Depression (HAM-D-24) and the Clinician-Administered Rating Scale for Mania (CARS-M). The authors were unable to statistically distinguish between risperidone and haloperidol in the amelioration of psychotic and manic symptoms. In addition, there was no difference in worsening of mania between the two agents in either subgroup (i.e., depressed or bipolar subgroups). For the total PANSS, risperidone produced a mean decrease of 16 points from baseline compared with a 14-point decrease with haloperidol. For the total CARS-M scale, risperidone and haloperidol produced mean change scores of 5 and 8 points, respectively, and for the CARS-M Mania subscale, 3 and 7 points, respectively. Additionally, risperidone produced a mean decrease of 13 points from the baseline 24-item HAM-D, compared with an 8-point decrease with haloperidol. In those patients who had more severe depressive symptoms (i.e., HAM-D baseline score >20), risperidone produced at least a 50% mean improvement in 12 (75%) of 16 patients in comparison to 8 (38%) of 21 patients receiving haloperidol. Haloperidol produced significantly more extrapyramidal side effects and resulted in more dropouts caused by any side effect. There was no difference between risperidone and haloperidol in reducing both psychotic and manic symptoms in this group of patients with schizoaffective disorder. Risperidone did not demonstrate a propensity to precipitate mania and was better tolerated than haloperidol. In those subjects with higher baseline HAM-D scores (i.e., >20), risperidone produced a greater improvement in depressive symptoms than haloperidol.

Do elder emergency department patients and their informants agree about the elder's functioning?

OBJECTIVE

To compare elder patients' and their informants' ratings of the elder's physical and mental function measured by a standard instrument, the Medical Outcomes Study Short Form 12 (SF-12).

METHODS

This was a randomized, cross-sectional study conducted at a university-affiliated community teaching hospital emergency department (census 65,000/year). Patients >69 years old, arriving on weekdays between 10 AM and 7 PM, able to engage in English conversation, and consenting to participate were eligible. Patients too ill to participate were excluded. Informants were people who accompanied and knew the patient. Elder patients were randomized 1:1 to receive an interview or questionnaire version of the SF-12. The questionnaire was read to people unable to read. Two trained medical students administered the instrument. The SF-12 algorithm was used to calculate physical (PCS) and mental (MCS) component scores. Oral and written versions were compared using analysis of variance. The PCS and MCS scores between patient-informant pairs were compared with a matched t-test. Alpha was 0.05.

RESULTS

One hundred six patients and 55 informants were enrolled. The patients' average (+/-SD) age was 77 +/- 5 years; 59 (56%; 95% CI = 46% to 65%) were women. There was no significant difference for mode of administration in PCS (p = 0.53) or MCS (p = 0.14) scores. Patients rated themselves higher on physical function than did their proxies. There was a 4.1 (95% CI = 99 to 7.2) point difference between patients' and their proxies' physical component scores (p = 0.01). Scores on the mental component were quite similar. The mean difference between patients and proxies was 0.49 (95% CI = 3.17 to 4.16). The half point higher rating by patients was not statistically significant (p = 0.79).

CONCLUSIONS

Elders' self-ratings of physical function were higher than those of proxies who knew them. There was no difference in mental function ratings between patients and their proxies. Switching from informants' to patients' reports in evaluating elders' physical function in longitudinal studies may introduce error.

Chronic inhalation studies of two types of stone wool fibers in rats

A summary is given of the pathology results after long-term inhalation in rats of insulation wool representing the new biosoluble types. The pathology results are compared with previously conducted long-term inhalation study with MMVF21 (traditional stone wool). The biosoluble fiber MMVF34/HT (HT) is characterized by a relatively high content of aluminum and a relatively low content of silica compared to the older MMVF21. HT has a high in vitro dissolution rate at pH 4.5, and a relatively low dissolution rate at pH 7.5. Male Fischer 344 rats were exposed at one exposure level of 30 mg/m(3) by nose-only inhalation of a well-characterized fiber test atmosphere. The fibers had been size selected to be largely rat respirable. The negative control group was exposed to filtered air. The exposure duration was 6 h/day, 5 days/wk for 104 wk, with a subsequent nonexposure period lasting until approximately 20% survival in the air control group. Interim sacrifices were performed at wk 13, 26, 52, 78, and 104 to monitor the progression of pulmonary change and fiber numbers. Effectively the main protocol for the previously conducted chronic study with MMVF21 was the same, except that there were three concentration levels (3, 16, and 30 mg/m(3)). In addition to the endpoints measured in the previous study, slides from both studies were evaluated for collagen deposition using a quantitative morphometric method. The results of the comparative study clearly showed a marked difference in the pulmonary pathogenicity of the MMVF21 and HT in terms of their fibrogenic potential. MMVF21 caused pulmonary fibrosis, but the HT fiber did not. The incidence of tumors for both the HT and the MMVF21 fiber was comparable to the control groups.

Cytokine changes after a marathon race

The influence of carbohydrate (1 l/h of a 6% carbohydrate beverage), gender, and age on pro- and anti-inflammatory plasma cytokine and hormone changes was studied in 98 runners for 1.5 h after two competitive marathon races. The marathoner runners were randomly assigned to carbohydrate (C, n = 48) and placebo (P, n = 50) groups, with beverages administered during the races in a double-blind fashion using color codes. Plasma glucose was higher and cortisol was lower in the C than in the P group after the race (P < 0.001). For all subjects combined, plasma levels of interleukin (IL)-10, IL-1 receptor antagonist (IL-1ra), IL-6, and IL-8 rose significantly immediately after the race and remained above prerace levels 1.5 h later. The pattern of change in all cytokines did not differ significantly between the 12 women and 86 men in the study and the 23 subjects > or =50 yr of age and the 75 subjects <50 yr of age. The pattern of change in IL-10, IL-1ra, and IL-8, but not IL-6, differed significantly between the C and the P group, with higher postrace values measured for IL-10 (109% higher) and IL-1ra (212%) in the P group and for IL-8 (42%) in the C group. In conclusion, plasma levels of IL-10, IL-1ra, IL-6, and IL-8 rose strongly in runners after a competitive marathon, and this was not influenced by age or gender. Carbohydrate ingestion, however, had a major effect in attenuating increases in cortisol and two anti-inflammatory cytokines, IL-10 and IL-1ra.

Severe Bordetella holmesii infection in a previously healthy adolescent confirmed by gene sequence analysis

We describe an immunocompetent adolescent who presented with exceptionally severe Bordetella holmesii infection, including previously undescribed manifestations. Sequelae included a severe restrictive lung defect due to pulmonary fibrosis.

Influence of neutral cyclodextrin concentration on plate numbers in capillary electrophoresis

A quantitative theory of plate number N in capillary electrophoresis was developed for buffers containing neutral cyclodextrins (CDs) capable of forming inclusion complexes. In the theory, N was modeled by longitudinal diffusion, injection extent, width of the detection window, and the detector time constant. The apparent mobility was modeled as a weighted sum of the mobilities of the free-solution analyte and the inclusion complex. The apparent diffusion coefficient was modeled as a similarly weighted sum. Both the apparent mobility and diffusion coefficient were corrected by functions that compensated for increases of buffer temperature caused by Joule heat. The experimental N's and apparent mobilities of neutral thiourea and of the anions, dansyl D- and L-leucine, dansyl D- and L-aspartic acid, benzoate, and 4-nitrophenolate, were determined in buffers containing from 0 to 15 mM beta-CD. The binding constants, and mobilities and diffusion coefficients of the free-solution analyte and inclusion complex, were calculated as regression coefficients by fitting theory to these determinations. The regression coefficients were shown to have physicochemical meaning, as assessed by literature values, independent measurements, and theoretical predictions. The assessment showed the Nernst-Einstein equation does not relate mobilities and diffusion coefficients at the electrolyte concentration used. The interdependence of mobilities, diffusion coefficients, binding constants, and other dispersion sources was interpreted to evaluate the factors affecting the variation of N with CD concentration. From the interpretation, an approximate equation for N in low-concentration CD buffers was derived. The equation depends on free-solution and inclusion-complex mobilities and diffusion coefficients, the binding constant, the potential difference over the effective capillary length, and the number of plates in a CD-free buffer.

Exercise-induced neuromuscular dysfunction under reflex conditions

The purpose of this research was to describe further the effects of exercise-induced muscle damage on reflex sensitivity. The subjects were eight physically active, but untrained males, between the ages of 18 and 29 years. The effects of eccentric and concentric exercise on patellar tendon reflex responses were determined. The 8 week experiment consisted of two, 5 day, test protocols with a 6 week wash-out period between test protocols. Each 5 day test protocol consisted of the following six test sessions: (1) day 1--baseline, (2) day 2 baseline, (3) day 2--immediate post-exercise, and (4-6) days 3-5: 24, 48, and 72 h post-exercise. On day 2, the subjects made either 100 fatiguing concentric or eccentric isotonic contractions using the right leg at 75% of the corresponding repetition maximum values. During each test session, the electromyogram (EMG) and force-time characteristics of basic and conditioned patellar tendon reflex responses were measured. The reflex amplitudes of basic and conditioned patellar tendon reflex responses were decreased following fatiguing concentric exercise. There were no immediate effects of fatiguing eccentric exercise on the basic and conditioned patellar tendon reflex responses, but the EMG amplitudes of these reflex responses were reduced on the days following eccentric exercise. The amount of conditioned patellar tendon reflex facilitation was decreased following the concentric exercise protocol and at 48 h post-eccentric exercise. Our conditioned reflex data suggest that post-exercise changes to the physiological mechanisms that modulate the recruitment gain of the alpha-motoneuron pool may depend upon the type of fatiguing exercise.

Tissue expression and plasma concentrations of TNFalpha, IL-1beta, and IL-6 following treadmill exercise in mice

Exercise can increase plasma inflammatory cytokine concentrations in humans, but tissue responses are not well studied. We examined plasma concentrations and tissue expression of TNFalpha, IL-1beta, and IL-6 following treadmill running in mice. C57B1/6 mice were randomly assigned to: non-exercise control (CON), sacrifice at 0 or 1.5 h after 60 min running (MOD0, MOD 1.5), sacrifice at 0, 1.5, or 3 h after fatiguing running (approximately 3 h) (EX0, EX1.5, EX3), or lipopolysaccharide (25 microg) with no exercise (LPS). Lung, liver, muscle, and brain mRNA expression was analyzed (n = 4-6/group) using reverse transcriptase-rapid polymerase chain reaction (RT-RPCR). Plasma cytokine concentrations were determined (n =4-10/group) by ELISA. Plasma IL-6 was higher in EX1.5, and lung TNFalpha mRNA was higher in EX1.5 and EX3 compared to CON (P < 0.05). No significant increases in plasma cytokine concentrations or tissue cytokine expression were found in other EX groups. LPS significantly increased these cytokine measures in tissues and plasma, with the exception of plasma IL-1beta which was undetectable. The source of the plasma IL-6 following exercise does not appear to be lung, liver, muscle, or brain tissue, and remains to be determined. These data also suggest that tissue level cytokine expression may not necessarily lead to increased plasma cytokine concentrations.

Overexpression of manganese superoxide dismutase protects lung epithelial cells against oxidant injury

To determine whether overexpression of antioxidant enzymes in lung epithelial cells prevents damage from oxidant injury, stable cell lines were generated with complementary DNAs encoding manganese superoxide dismutase (MnSOD) and/or catalase (CAT). Cell lines overexpressing MnSOD, CAT, or MnSOD + CAT were assessed for tolerance to hyperoxia or paraquat. After exposure to 95% O(2) for 10 d, 44 to 57% of cells overexpressing both MnSOD and CAT and 37 to 47% of cells overexpressing MnSOD alone were viable compared with 7 to 12% of empty vector or parental cells (P < 0.05). To assess if viable cells were capable of cell division after hyperoxic exposures (up to 5 d), a clonogenicity assay was performed. The clonogenic potential of cells overexpressing MnSOD + CAT and MnSOD alone were significantly better than those expressing CAT alone or empty vector controls. In addition, 54 to 72% of cells overexpressing both MnSOD and CAT survived in 1 mM paraquat compared with 58 to 73% with MnSOD alone and 27% with control cells. Overexpression of CAT alone did not improve survival in hyperoxia or paraquat. The combination of MnSOD + CAT did not provide additional protection from paraquat. Data demonstrate that overexpression of MnSOD protects cells from oxidant injury and CAT offers additional protection from hyperoxic injury when co-expressed with MnSOD.

Clonidine-induced hyperphagia in monkeys: evidence for alpha 2-noradrenergic receptor mediation

The mechanism of clonidine-induced hyperphagia and weight gain in monkeys was studied in 11 Stumptail macaques. Clonidine induced a significant increase in food intake over baseline levels and a significant weight gain after the 3-day treatment period. Both changes induced by clonidine were antagonized by the alpha 2-noradrenergic antagonist yohimbine, but not by prazosin, an alpha 1-noradrenergic antagonist. These results suggest that clonidine-induced hyperphagia and weight gain in monkeys are mediated through alpha 2-noradrenergic receptors.

Blood pressure and indices of glomerular filtration area in hypertensive and normotensive Prague rats

The involvement of the kidney in the pathogenesis of hypertension has long been recognised, although the specific renal mechanisms underlying this phenomenon are still unknown. A current hypothesis attributes hypertension to a reduction in glomerular filtration area by glomerular loss. The present study analyses the relationship between glomerular number and volume and conscious systolic blood pressure (SBP) in 4- to 53-week-old hypertensive (PHR) and normotensive (PNR) rats of the Prague strain. Adult PHRs had higher SBP, were larger and had larger kidneys than PNRs, but 20% fewer glomeruli. A significant negative correlation between SBP and glomerular number was found in PHR males, but not in PHR females or PNRs. There was no correlation at all between glomerular volume and SBP and, in young animals, both SBP and glomerular number were higher in PHRs than in PNRs. In addition, in adult PHRs, glomerular volume and SBP were higher in males than in females. In summary, a generally valid, causal relationship linking raised blood pressure to decreased glomerular number or volume could not be demonstrated in the Prague rat model of genetically determined hypertension. The nature of the renal mechanism(s) determining the hypertension in this model remains unknown.

Hydrotherapy in labor

Maternal anxiety and pain prolong labor and contribute to fetal distress. Hydrotherapy during labor may promote relaxation and decrease pain without the risks caused by other treatments. In this pilot study the psychophysiological effects of hydrotherapy on maternal anxiety and pain during labor were examined. Using a randomized, pretest-posttest control group design with repeated measures, 18 term parturients were assigned to a control or an experimental group. Experimental subjects were placed in a tub of 37 degrees C water for 1 hr during early labor. The Wilcoxon two-sample test revealed statistically significant effects. At 15 min bathers' anxiety and pain scores were decreased compared to nonbathers. At 60 min bathers' pain scores were decreased compared to nonbathers. After 15 min of immersion, bathers had a significantly greater increase in plasma volume than nonbathers. No significant differences were found in urine catecholamines or maternal-fetal complications. The small sample limits conclusions, but the findings offer preliminary support for the therapeutic effects of bathing in labor for acute, short-term anxiety and pain reduction.

Hyperoxia inhibits oxidant-induced apoptosis in lung epithelial cells

It has previously been shown that hyperoxia induces nonapoptotic cell death in cultured lung epithelial cells, whereas hydrogen peroxide (H(2)O(2)) and paraquat cause apoptosis. To test whether pathways leading to oxidative apoptosis in epithelial cells are sensitive to molecular O(2), A549 cells were exposed to 95% O(2) prior to exposure to lethal concentrations of H(2)O(2). The extent of H(2)O(2)-induced apoptosis was significantly reduced in cells preexposed to hyperoxia compared with room-air controls. Preexposure of the hyperoxia-resistant HeLa-80 cell line to 80% O(2) also inhibited oxidant-induced apoptosis, suggesting that this inhibition is not due to O(2) toxicity. Because hyperoxia generates reactive oxygen species and activates the redox-sensitive transcription factor nuclear factor kappa B (NF-kappa B), the role of antioxidant enzymes and NF-kappa B were examined in this inhibitory process. The onset of inhibition appeared to be directly related to the degradation of I kappa B and subsequent activation of NF-kappa B (either by hyperoxia or TNF-alpha), whereas no significant up-regulation of endogenous antioxidant enzyme activities was found. In addition, suppression of NF-kappa B activities by transfecting A549 cells with a dominant-negative mutant construct of I kappa B significantly augmented the extent of H(2)O(2)-induced apoptosis. These data suggest that hyperoxia inhibits oxidant-induced apoptosis and that this inhibition is mediated by NF-kappa B.

Superoxide dismutase for preventing chronic lung disease in mechanically ventilated preterm infants

BACKGROUND

Free oxygen radicals have been implicated in the pathogenesis of chronic lung disease in preterm infants. Superoxide dismutase is a naturally occurring enzyme which provides a defence against such oxidant injury. Exogenously administered superoxide dismutase has been tested in clinical trials to prevent chronic lung disease in preterm infants.

OBJECTIVES

To determine if exogenously administered superoxide dismutase is efficacious in the prevention of chronic lung disease in preterm infants who are mechanically ventilated, and efficacious in decreasing the following outcomes: bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, necrotizing enterocolitis, patent ductus arteriosus and mortality. To determine the frequency and nature of adverse effects of superoxide dismutase.

SEARCH STRATEGY

We searched Medline (1966 - 2000) and the Cochrane Controlled Trials Register (CCTR) using the following keywords: [bronchopulmonary dysplasia OR chronic lung disease] AND superoxide dismutase, limited to human studies in newborn infants (infant, newborn). We hand searched the reference lists of articles located and the abstracts of the Society for Pediatric Research (USA) (published in Pediatric Research) from 1980 - 2000.

SELECTION CRITERIA

Randomized controlled trials where subjects were preterm infants who had developed or were at risk of developing respiratory distress syndrome requiring assisted ventilation and who were randomly allocated to receive either superoxide dismutase (in any form, by any route) or placebo or no treatment. We included studies which reported any of the following outcomes: chronic lung disease, bronchopulmonary dysplasia, any intraventricular hemorrhage, intraventricular hemorrhage grades III/IV, patent ductus arteriosus, periventricular leukomalacia, retinopathy of prematurity, necrotizing enterocolitis, neonatal mortality, death prior to discharge and neurodevelopmental outcome.

DATA COLLECTION AND ANALYSIS

We extracted and assessed separately all data for each study and entered final data into RevMan. We did not perform subgroup analyses (which were originally planned) because only two studies were eligible for inclusion. We assessed the methodological quality of the studies by assessing the risk for bias. We pooled the outcomes of infants who had developed bronchopulmonary dysplasia at 28 days with those who had died at 28 days to derive the combined outcome of bronchopulmonary dysplasia or death at 28 days. Similarly we pooled the outcomes of infants who had respiratory problems after discharge with those who had died prior to discharge to derive the combined outcome of respiratory problems after discharge or death. We used the standard method of the Cochrane Neonatal Review Group for statistical analysis, using a fixed effect model.

MAIN RESULTS

Two randomized controlled trials were included for analysis. No differences were found in either study or in the pooled data in death prior to discharge, oxygen dependency at 36 weeks corrected age, oxygen dependency at 28 days of life or in other outcomes. In one study (Rosenfeld 1984), survivors who had been treated with superoxide dismutase had a shorter duration of continuous positive airway pressure (4.9 vs 9.7 days), a lower frequency of respiratory problems after discharge (relative risk 0.33, 95% confidence limits 0.11, 0.96) and a lower frequency of chest radiograph abnormalities (relative risk 0.30, 95% confidence limits 0.11, 0.87) compared to survivors who received placebo. A third study was available only in abstract form and will be evaluated for inclusion after publication.

REVIEWER'S CONCLUSIONS

Based on currently available published trials, there is insufficient evidence to draw firm conclusions about the efficacy of superoxide dismutase in preventing chronic lung disease of prematurity. Data from a small number of treated infants suggest that it is well tolerated and has no serious adverse effects.

Effects of carbohydrate and chromium ingestion during intermittent high-intensity exercise to fatigue

PURPOSE

This study was designed to test the hypothesis that addition of chromium (Cr) to a carbohydrate-electrolyte drink would enhance the reported benefits of carbohydrate on exercise capacity during intermittent high-intensity shuttle running.

METHODS

Eight physically active men performed 3 exercise trials while ingesting 6% carbohydrate-electrolyte (CHO), CHO plus chromium picolinate (400 mg) (CHO + Cr+3), or placebo (P) using a double-blind, counterbalanced design. Each trial consisted of 5 3 15 min bouts of shuttle running (walk, sprint, and run at 95 and 55% of estimated VáO2max, separated by 3-min rest). This was followed by a fatigue test (running alternating 20-m lengths at 55 and 95% of estimated VáO2 until fatigue).

RESULTS

During the standardized shuttle running, blood glucose was higher with both CHO and CHO + Cr+3 than P. Plasma free fatty acid was higher in P than both CHO and CHO + Cr+3 at 75 min of exercise and at fatigue. In the fatigue test, subjects ran longer with both CHO and CHO + Cr+3 than P.

CONCLUSIONS

The data confirm an ergogenic benefit of ingesting CHO during exercise designed to imitate sports like basketball, soccer, and hockey, but do not support the hypothesis that the addition of Cr would enhance this effect.

Inhalation of poorly soluble particles. I. Differences in inflammatory response and clearance during exposure

Results from animal studies have indicated some uncertainties over the validity of a single general occupational control limit for all types of "particulates (insoluble) not otherwise classified" (PNOC) (ACGIH, 2000). Therefore, to examine the extent to which a given control limit may be valid for nontoxic dusts with different physical characteristics, this study compared the pulmonary effects in rats of inhalation exposure to two poorly soluble dusts of similar density and with relatively low toxicity: titanium dioxide and barium sulfate. The objectives were to compare the dusts in (a) their buildup and clearance in the lungs during inhalation; (b) their transfer to lymph nodes; (c) the changes, with time, in the lavageable cell population; and (d) the pathological change from histology. The exposure aerosol concentrations were selected to achieve similar mass and volume lung burdens for both dusts and to attain "overload" over the common exposure periods of about 4 mo and 7 mo. Despite obtaining similar lung burdens for both dusts, there was significantly more translocation of TiO(2) to the hilar lymph nodes than with BaSO(4). It was also found that clearance of TiO(2) was retarded whereas clearance of BaSO(4) was not. Trends in these data were clarified by the use of a simple model of particle clearance. Retardation of particle clearance and translocation to the lymph nodes are markers of the condition known as "overload" in which the alveolar macrophage-based clearance of particles from the deep lung is impaired. In addition, bronchoalveolar lavage showed that TiO(2) caused significantly more recruitment of inflammatory neutrophils to lungs than BaSO(4). These differences between the dusts were not due to differences in toxicity, solubility, or lung deposition. The explanation that the different responses are due to the different particle size distributions of the two dust types is examined in a companion paper (Tran et al., this issue).

Autologous graft-versus-host disease induction in advanced breast cancer: role of peripheral blood progenitor cells

The purpose of the present study was to investigate the impact of the use of peripheral blood progenitor cells (PBPCs) on the induction of autologous graft-versus-host disease (GVHD) in patients with advanced breast cancer. 14 women with stage IIIB and 36 women with stage IV breast cancer received cyclosporine (CsA) 2.5 mg kg-1 i.v. daily, d 0-28, and interferon-gamma (IFNg) 0.025 mg/m2 s.c. qod, d7-28, following PBPC-T +/- bone marrow transplantation (BMT). Preceding high-dose chemotherapy consisted of cyclophosphamide 6 g/m2 and thiotepa 800 mg/m2. Histologically proven > or = grade II cutaneous GVHD was induced in18/50 (36%) of patients and was independent of the source of haematopoietic support. In vitro studies showed that post-transplant, 76% of patients had developed auto-cytotoxicity against their own pre-transplant PHA-lymphoblasts. A significant correlation between the occurrence of GVHD > or = grade II and cytolysis was observed in the NK cell-line K562 and the T47D breast cancer cell-line. With a median follow-up of 2(1/2) years, the overall survival (OS) is 58%, the disease-free survival (DFS) 26%, both independent of the development of GVHD and similar to what has been observed in other studies on high-dose chemotherapy in advanced breast cancer. It therefore remains unclear whether the induction of autologous GVHD with the occurrence of auto-cytotoxic lymphocytes can result in an anti-tumour effect in this group of patients.

Justification of statistical overlap theory in programmed temperature gas chromatography: thermodynamic origin of random distribution of retention times

A specific distribution of compounds' standard-state changes of enthalpy and entropy between mobile and stationary phases in programmed temperature gas chromatography (PTGC) is shown to produce the Poisson distribution of retention times often postulated in statistical-overlap theory (SOT). A three-part model is proposed, in which the enthalpy change is Poisson distributed, the average entropy change depends on the enthalpy change, and the actual entropy change varies in a uniformly random manner about the average entropy change. To test the model, the entropy and enthalpy changes of 350 aliphatic and aromatic hydrocarbons in petroleum were calculated with commercial GC software. These changes are shown to follow the three-part model. The model then was used with Monte Carlo methods to mimic the enthalpy and entropy changes. The substitution of the mimicked enthalpy and entropy changes into an equation for the retention temperature in PTGC is shown to produce a Poisson distribution of retention times that is statistically significant. This finding establishes a scientific link between the thermodynamics governing retention in PTGC and the superficially ad hoc assumption of the Poisson retention time distribution in SOT. Similar thermodynamic distributions are found for flavors and fragrances and for tetrachlorodibenzo-p-dioxins and furans, which follow SOT based on the Poisson distribution, but not for polychloronaphthalenes, which do not follow that SOT.

Decrease in reelin and glutamic acid decarboxylase67 (GAD67) expression in schizophrenia and bipolar disorder: a postmortem brain study

BACKGROUND

Reelin (RELN) is a glycoprotein secreted preferentially by cortical gamma-aminobutyric acid-ergic (GABAergic) interneurons (layers I and II) that binds to integrin receptors located on dendritic spines of pyramidal neurons or on GABAergic interneurons of layers III through V expressing the disabled-1 gene product (DAB1), a cytosolic adaptor protein that mediates RELN action. To replicate earlier findings that RELN and glutamic acid decarboxylase (GAD)(67), but not DAB1 expression, are down-regulated in schizophrenic brains, and to verify whether other psychiatric disorders express similar deficits, we analyzed, blind, an entirely new cohort of 60 postmortem brains, including equal numbers of patients matched for schizophrenia, unipolar depression, and bipolar disorder with nonpsychiatric subjects.

METHODS

Reelin, GAD(65), GAD(67), DAB1, and neuron-specific-enolase messenger RNAs (mRNAs) and respective proteins were measured with quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) or Western blot analyses. Reelin-positive neurons were identified by immunohistochemistry using a monoclonal antibody.

RESULTS

Prefrontal cortex and cerebellar expression of RELN mRNA, GAD(67) protein and mRNA, and prefrontal cortex RELN-positive cells was significantly decreased by 30% to 50% in patients with schizophrenia or bipolar disorder with psychosis, but not in those with unipolar depression without psychosis when compared with nonpsychiatric subjects. Group differences were absent for DAB1,GAD(65) and neuron-specific-enolase expression implying that RELN and GAD(67) down-regulations were unrelated to neuronal damage. Reelin and GAD(67) were also unrelated to postmortem intervals, dose, duration, or presence of antipsychotic medication.

CONCLUSIONS

The selective down-regulation of RELN and GAD(67) in prefrontal cortex of patients with schizophrenia and bipolar disorder who have psychosis is consistent with the hypothesis that these parameters are vulnerability factors in psychosis; this plus the loss of the correlation between these 2 parameters that exists in nonpsychotic subjects support the hypothesis that these changes may be liability factors underlying psychosis.

Transepithelial chloride conductance in amphibian skin: regulatory mechanisms and localization

The transepithelial transport of Na+ by amphibian skin must be accompanied by the corresponding anion, Cl-, and much effort has been devoted to the characterization of Cl- transport. The transepithelial Cl- conductance, G(Cl), is activated by voltage and adenosine 3',5'-cyclic monophosphate (cAMP), shows rectification, requires the presence of Cl- in the pathway and is influenced by factors modifying intracellular signalling cascades and by metabolic poisons such as cyanide (CN-). Until recently, these findings were interpreted as strong evidence for a transcellular path, for which, given the impermeability of the principal cells for Cl-, the mitochondria-rich cells (MRC) are the only candidate. This was supported by the apparent parallelism between G(Cl) and the density of MRC (D(mrc)). Data accumulated in recent years, however, raise serious doubts as to the validity of this concept. The single-channel conductance derived from various techniques is too small by an order of magnitude to account for the observed G(Cl), the very slow time course of conductance activation is not reconcilable with any known membrane channel gating processes, a more thorough examination of the relationship between G(Cl) and D(mrc) fails to show any consistent pattern and analysis of current density immediately above the transporting epithelium using the vibrating voltage probe shows current peaks associated with only a small fraction of MRC, and even so, these current peaks account for about 20% of the transepithelial current. The remaining 80% of the current cannot be localized to specific structures. Given the increasing evidence for close cellular control of tight-junction function, the foregoing findings are equally consistent with an additional, major, paracellular pathway for Cl-. A comprehensive description of Cl- transport must await the final resolution of the transport pathway(s).

Exercise and tumor development in a mouse predisposed to multiple intestinal adenomas

Epidemiological evidence suggests that physical activity may be protective against the development of colon cancer. Potential mechanisms remain largely unexplored due to the paucity of appropriate experimental models.

PURPOSE

The purpose of this study was to examine the effect of exercise training on polyp development in an induced mutant mouse strain predisposed to multiple intestinal neoplasia (Min mouse).

METHODS

Three-week-old male and female heterozygotes were randomly assigned to control (CON; 10 males, 6 females) or exercise (EX; 11 males, 11 females) groups. In the first week, EX mice were acclimated to treadmill running at 10-18 m x min(-1) for 15-60 min x d(-1). From 4-10 wk of age, mice ran at 18-21 m x min(-1) for 60 min. CON mice sat in Plexiglas lanes suspended above the treadmill for the same time periods. At 10 wk of age, the mice were sacrificed and the intestines removed, opened, and counted for polyps.

RESULTS

Skeletal muscle oxidative capacity increased with training as shown by a 64% increase in citrate synthase activity in the gastrocnemius/soleus muscle of EX compared with CON (P = 0.009). There were no significant effects of exercise in the males and females combined on small intestine, colon, or total intestinal polyps (P > 0.05). When analyzed separately, however, there were fewer colon and total polyps in the EX than in the CON males, although the difference was not statistically significant (P = 0.06).

CONCLUSIONS

These results suggest that seven weeks of exercise training do not affect the development of intestinal polyps in the Min mouse. Further studies are required to determine if a true sex difference exists or if variations on the current training protocol may affect tumor outcomes.

Pathogenicity of a special-purpose glass microfiber (E glass) relative to another glass microfiber and amosite asbestos

This article describes the activity of an E-glass microfiber (104E) during chronic inhalation and intraperitoneal injection studies in rats. Results are compared with another microfiber of similar dissolution rate (k(dis)), code 100/475, and the more durable amosite asbestos, both of which we had previously used in similar experiments (Davis et al., 1996). Rats were exposed to aerosol concentrations of 1000 fibers (longer than 5 microm)/ml, as measured by optical microscopy, for 7 h/day, 5 days/wk. Subgroups of rats were followed for mean lung burden, early and late signs of fibrosis, and tumor incidence. At the end of 12 mo of exposure, the mean number of 104E fibers of all lengths in the lungs was approximately double that for amosite but two-thirds of that for 100/475. For fibers longer than 15 microm, the mean 104E burden was similar to that for the amosite and more than twice that of the 100/475. After a 12-mo recovery period, the retained lung burdens (of fibers of all lengths) were approximately 30% of those at 12 mo for both microfibers, and somewhat higher (approximately 44%) for amosite. Amosite and 100/475 fibers longer than 15 microm were more persistent in the lungs than 104E fibers. The chemical composition of 104E fibers did not appear to have been significantly altered by up to 24 mo of residence in lung tissue, whereas the composition of 100/475 was substantially altered over the same time period. From the inhalation study, out of the pathology subgroup of 43 animals exposed to 104E microfibers, 10 had lung tumors (7 carcinoma, 3 adenoma) and 2 had mesotheliomas, whereas in 42 rats exposed to amosite asbestos, there were 16 lung tumors (7 carcinoma, 9 adenoma) and 2 mesotheliomas. The 104E- and amosite-treated animals had similar levels of fibrosis. In contrast, 38 animals treated with 100/475 had little fibrosis, 4 lung tumors (adenomas), and no mesotheliomas. The greater pathogenicity of the 104E fibers, compared to 100/475 fibers, might be partly explained by the greater numbers of long fibers retained in the lung after 12 mo of inhalation. However, we speculate that modification of surface properties by extensive selective leaching of some glass components reduces the toxic potential of 100/475. In a parallel intraperitoneal injection study, 104E caused considerably more mesotheliomas (21 rats out of 24) than 100/475 (8 rats out of 24). In addition, 104E appeared to be more active than amosite asbestos, since mesotheliomas appeared much more quickly in the 104E-treated animals. In conclusion, we have shown that two microfiber types, 100/475 and 104E, of similar dissolution rates, had markedly different pathogenicity in rats. We believe that this contrast is only partly due to differences in numbers of long fibers and that differences in surface properties of the fibers, possibly due to proportionately greater leaching of 100/475 fibers, play an important role.