Basal Ti level in the human placenta and meconium and evidence of a materno-foetal transfer of food-grade TiO2 nanoparticles in an ex vivo placental perfusion model.

BACKGROUND: Titanium dioxide (TiO2) is broadly used in common consumer goods, including as a food additive (E171 in Europe) for colouring and opacifying properties. The E171 additive contains TiO2 nanoparticles (NPs), part of them being absorbed in the intestine and accumulated in several systemic organs. Exposure to TiO2-NPs in rodents during pregnancy resulted in alteration of placental functions and a materno-foetal transfer of NPs, both with toxic effects on the foetus. However, no human data are available for pregnant women exposed to food-grade TiO2-NPs and their potential transfer to the foetus. In this study, human placentae collected at term from normal pregnancies and meconium (the first stool of newborns) from unpaired mothers/children were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and scanning transmission electron microscopy (STEM) coupled to energy-dispersive X-ray (EDX) spectroscopy for their titanium (Ti) contents and for analysis of TiO2 particle deposition, respectively. Using an ex vivo placenta perfusion model, we also assessed the transplacental passage of food-grade TiO2 particles. RESULTS: By ICP-MS analysis, we evidenced the presence of Ti in all placentae (basal level ranging from 0.01 to 0.48 mg/kg of tissue) and in 50% of the meconium samples (0.02-1.50 mg/kg), suggesting a materno-foetal passage of Ti. STEM-EDX observation of the placental tissues confirmed the presence of TiO2-NPs in addition to iron (Fe), tin (Sn), aluminium (Al) and silicon (Si) as mixed or isolated particle deposits. TiO2 particles, as well as Si, Al, Fe and zinc (Zn) particles were also recovered in the meconium. In placenta perfusion experiments, confocal imaging and SEM-EDX analysis of foetal exudate confirmed a low transfer of food-grade TiO2 particles to the foetal side, which was barely quantifiable by ICP-MS. Diameter measurements showed that 70 to 100% of the TiO2 particles recovered in the foetal exudate were nanosized. CONCLUSIONS: Altogether, these results show a materno-foetal transfer of TiO2 particles during pregnancy, with food-grade TiO2 as a potential source for foetal exposure to NPs. These data emphasize the need for risk assessment of chronic exposure to TiO2-NPs during pregnancy.

A mean body temperature of 37°C for incubated preterm infants is associated with lower energy costs in the first 11 days of life.

AIM: This randomised trial compared the energy costs of providing incubated preterm infants born before 32 weeks of gestation with homeothermia using either air temperature control (ATC) or skin servocontrol (SSC). METHODS: We studied 38 incubated preterm infants for the first 11 days of life, calculating the frequency of hypothermia (<36.0°C), hyperthermia (>37.5°C) and thermal challenge, together with energy costs, based on a change in incubator air temperature of 2°C above or below thermoneutrality. RESULTS: The daily mean incubator air temperature was higher in ATC than SSC (p < 0.05) for the first 6 days, and the mean body temperature was higher in ATC (37.0 ± 0.03°C) than SSC (36.8 ± 0.02; p < 0.01) over the whole study period. The frequency of moderate hyperthermia was higher in ATC (p < 0.001), whereas warm and cold thermal challenges were higher in SSC (p < 0.001). The two groups did not differ in terms of energy costs. The time to recover birthweight was shorter in ATC (p < 0.05). CONCLUSION: In incubators using ATC, a body temperature of 37°C was associated with lower energy costs and greater weight gain at 11 days of life for preterm infants. Future studies should test SSC shielded abdominal skin temperature set to 37°C.

Impact of nursing care on temperature environment in preterm newborns nursed in closed convective incubators.

AIMS: Very-low-birth-weight (VLBW) neonates require regular nursing procedures with frequent opening of the incubator resulting in a decrease in incubator air temperature. This study was designed to assess changes in the thermal status of VLBW neonates according to the type of nursing care and incubator openings. METHODS: Thirty-one VLBW neonates (mean gestational age: 28.7 ± 0.3 weeks of gestation) were included. Over a 10-day period, each opening of the incubator was recorded together with details about caregiving. Body temperature was recorded continuously, and door opening and closing events were recorded by a video camera. RESULTS: This study analysed 1,798 caregiving procedures with mean durations ranging from 6.2 ± 2.1 to 88.5 ± 33.4 min. Abdominal skin temperature decreased by up to 1.08°C/h for procedures such as tracheal intubation (p < 0.01). The temperature decrease was strongly correlated with the type of procedure (p < 0.01), incubator opening (p < 0.01) and procedure duration (p < 0.01). The procedure duration accounted for only 10% of the abdominal skin temperature change (p < 0.01). CONCLUSIONS: For VLBW neonates nursed in skin temperature servo-control incubators, the decrease in abdominal skin temperature during caregiving was correlated with the type of procedure, incubator opening modalities and procedure duration. These parameters should be considered to optimize the thermal management of VLBW neonates.

Mast cells mediate Pseudomonas aeruginosa lipopolysaccharide-induced lung inflammation in rat.

Activated mast cells have been demonstrated to play a pivotal role in Pseudomonas aeruginosa lung infections. However, there is no report about the involvement of mast cells in P. aeruginosa lipopolysaccharide (LPS)-induced lung inflammation. This study aimed at evaluating the role of mast cells in P. aeruginosa LPS-induced lung inflammation in rats. Mast cells stabilization was carried out by intraperitoneal injections of cromolyn. Lung inflammation was induced by the intratracheal instillation of P. aeruginosa LPS (5 µg/kg bw) and inflammatory status was evaluated 4 h post-LPS instillation. We found that activated mast cells could constitute a pivotal source of several inflammatory cytokines, including TNF-α, IL-1ß, and IL-6. These cells might regulate polymorphonuclear neutrophil (PMN) recruitment and be implicated in the alteration of alveolar-capillary permeability via the release of TNF-α and IL-1ß. We also detected that activated mast cells could be involved in the alteration of the expression of two epithelial tight junction proteins (claudin-1 and occludin) during the acute phase of inflammation. Our results suggest that activated mast cells might play a critical role in P. aeruginosa LPS-induced lung inflammation. Therefore, mast cell stabilization may be a potential novel approach for the prevention and treatment of P. aeruginosa-induced lung infections.

Diversity and composition of macroinvertebrate communities in a rare inland salt marsh.

Inland salt marshes are rare habitats in the Great Lakes region of North America, formed on salt deposits from the Silurian period. These patchy habitats are abiotically stressful for the freshwater invertebrates that live there, and provide an opportunity to study the relationship between stress and diversity. We used morphological and COI metabarcoding data to assess changes in diversity and composition across both space (a transect from the salt seep to an adjacent freshwater area) and time (three sampling seasons). Richness was significantly lower at the seep site with both datatypes, while metabarcoding data additionally showed reduced richness at the freshwater transect end, consistent with a pattern where intermediate levels of stress show higher diversity. We found complementary, rather than redundant, patterns of community composition using the two datatypes: not all taxa were equally sequenced with the metabarcoding protocol. We identified taxa that are abundant at the salt seep of the marsh, including biting midges (Culicoides) and ostracods (Heterocypris). We conclude that (as found in other studies) molecular and morphological work should be used in tandem to identify the biodiversity in this rare habitat. Additionally, salinity may be a driver of community membership in this system, though further ecological research is needed to rule out alternate hypotheses.

Dramatic improvement in survival after lung transplantation over time: a single center experience.

Lung transplantation (LT) is a recognized procedure for selected patients with end-stage respiratory failure. We performed 123 LT, including 32 single lung, 84 double lung, and 7 heart-lung transplantations in 48 patients with chronic obstructive pulmonary disease (COPD), 13 patients with pulmonary hypertension (PH), 33 with cystic fibrosis (CF), and 29 with interstitial lung disease (ILD) between July 1990 and January 2008. Survival was compared for periods before and after December 2001. The mean age of patients was 44.4 years (range 16-66.5 years); 84 (69%) were men. Before LT, 1 second forced expiratory volume was 28.7% +/- 18.1% and PaCO(2) = 6.3 kPa. Fifty-five patients were on noninvasive ventilation. Cold ischemia time was 320 +/- 91 minutes. Cardiopulmonary bypass (CPB) was used in 77 patients (64%). There were 18 early surgical reinterventions, 8 extracorporeal membrane oxygenations, and 38 bronchial stent insertions among 206 at-risk bronchial sutures. Crude survivals were 69%, 58%, 41%, and 18% at 1, 2, 5, and 10 years, respectively. Comparing before (n = 70 with 15 CF) vs after December 2001 (n = 53 with 17 CF), survivals were 63% vs 78%, 51% vs 71%, and 33% vs 60% at 1, 2, and 5 years, respectively (P = .01) and for CF patients, 52% vs 100%, 52% vs 94%, and 25% vs 94% at 1, 2, and 5 years, respectively (P = .005). There was significant improvement in survival before and after 2001 in 123 LT and particularly among CF patients. Improvement in survival after LT may be related to the sum of numerous changes in our practice since December 2001, including the use of pulmonary rehabilitation pre-LT, extracellular pneumoplegia, statins, macrolides for chronic rejection, monitoring of Epstein-Barr blood load, changes in maintenance immunosuppressants, as well as position movement up the coordinator nurse and learning curve.

How do parents perceive adverse drug events of their children's anticonvulsant medication?

BACKGROUND: The main source of knowledge on adverse drug events (ADE) are physicians' reports in controlled clinical trials. In contrast, little is known about the parents' perception of ADE of anticonvulsants their children receive. METHODS: After approval by the local ethics committee, we performed a survey in a neuropediatric outpatient clinic of a university hospital. Based on a structured questionnaire, we interviewed parents of children with current anticonvulsant treatment regarding (i) their fears about potential ADE, (ii) experienced ADE according to parents, and (iii) implications of ADE on the child's life. RESULTS: Parents of 150 patients took part in the interview. (i) 95 (63.3%) parents expressed fears concerning ADE, mostly liver injury/liver failure (33 [22%]). (ii) 129 (86%) parents reported experienced ADE, mostly sedation (65 [43.3%]) and abnormal behavior (54 [36%]). (iii) Parents reported substantial implications of ADE on the child's daily life for 84 (56%) children, and 63 (42%) parents expressed a negative impact on the child's development. CONCLUSION: We recognized a great discrepancy between those ADE that were feared and those that were experienced. Parents feared life-threatening ADE and experienced less severe ADE that nevertheless have a negative impact on the child's daily life.

Impact of prenatal and postnatal exposure to the pesticide chlorpyrifos on the contraction of rat ileal muscle strips: involvement of an inducible nitric oxide synthase-dependent pathway.

BACKGROUND: Prenatal/postnatal exposure to insecticides has been linked to developmental disorders in adulthood. Chlorpyrifos (CPF) is a widely used organophosphorus acetylcholinesterase (AChE)-inhibiting insecticide. The present study established whether prenatal and postnatal exposure to CPF is associated with intestinal motor dysfunction in adult rats. METHODS: Three groups of pregnant rats were exposed to either CPF (1 or 5 mg/kg/day; the CPF1 and CPF5 groups) or vehicle (the control group) by gavage from gestational day 1 until weaning. At weaning, the pups were separated from their dams and individually gavaged (with the same dose) until postnatal day 60. We then measured in vivo intestinal transit and the in vitro contractile responses of ileal smooth muscle strips to electrical field stimulation. Expression of inducible nitric oxide synthase (iNOS) in the ileum was determined using qRT-PCR and immunoblots. Morphometry and AChE assays were also performed. KEY RESULTS: At adulthood, the mean body mass was lower in the CPF1 and CPF5 groups than in controls. CPF5 exposure was associated with weaker in vitro contraction of ileal muscle strips, which was reversed by adding the NOS inhibitor (L-NAME). There was no significant intergroup difference in the mean in vivo transit time. Exposure to CPF was associated with greater iNOS expression, lower AChE activity and reduced circular and longitudinal smooth muscle thickness. CONCLUSIONS & INFERENCES: Prenatal and postnatal exposure to CPF in the rat is associated with weaker contraction of ileal longitudinal smooth muscle via a nitrergic mechanism with increased iNOS expression.

[Evaluation of the measurement of hemoglobin by the Hemocue System® in the preterm neonate less than 28 days old]. / Évaluation de la mesure du taux d'hémoglobine par Hémocue® chez le nouveau-né prématuré de moins de 28 jours de vie.

BACKGROUND: Hemoglobin (Hb) measurement is essential for the monitoring of anemia in preterm neonates to assess if any bleeding (pulmonary, cerebral, digestive) is present. EDTA samples require 500 µL vs. 10 µL for the Hemocue(®) system. This system has been evaluated and validated in adults and children but not in preterm neonates with fetal hemoglobin. The aim of the study was to compare Hb measurement with the Hemocue(®) system vs. the EDTA laboratory system on fetal Hb in preterm neonates. MATERIALS AND METHODS: This was a prospective study conducted in the preterm intensive care unit in the Amiens Hospital. Preterm neonates, before 28 days of life, requiring EDTA (Hb) measurement were included. Two Hemocues(®) were performed at the same time. Postnatal age (correlated to the fetal hemoglobin level decrease), blood sample site, and other factors that could influence the Hb result were evaluated. RESULTS: Seventy-six EDTA and 152 Hemocue(®) samples from 38 preterm neonates were included. The term was 28.1±3.7 weeks of gestation, the birth weight was 1215.5±657 g. We found a good correlation between the Hemocue(®) and EDTA samples (Hemocue(®)=EDTA*0.94-0.4; R(2)=0.63; P<0.001). The influence of confounding factors was insignificant. CONCLUSION: The use of the Hemocue(®) system showed a good correlation with the EDTA measurement of fetal Hb, with a moderate bias (-0.2±1.5 g/dL), which remained stable for the first 28 days of life.

Ticarcillin disodium in anaerobic infections.

Twenty-five patients were treated with ticarcillin disodium, 18 of whom had anaerobic infections that included pleuropulmonary infections (seven), mandibular osteomyelitis (four), perirectal abscess (two), sepsis, primary site unknown (one), liver abscess (one), pelvic abscess (one), decubitus ulcer (one), and synergistic gangrene (one). Seven had no anaerobic infections. Three had anaerobic septicemia. Culture results included anaerobes: peptococci (ten), peptostreptococci (ten), Bacteroides fragilis (six), Bacteroides not fragilis (ten), eubacteria (three), fusobacteria (two), Clostridium (one), Veillonella (one), and acidaminococcus (one); aerobes: Proteus (three), Klebsiella (two), Escherichia coli (two), and streptococci (two). Six patients with mixed aerobic infections initially received gentamicin sulfate in addition. The serum levels were 110 +/- 20 microgram/ml one hour after intravenous infusion of 5 g of ticarcillin disodium. All anaerobic isolates were susceptible at less than or equal to 100 microgram/ml and 85% by less than or equal to 25 microgram/ml of ticarcillin. Sixteen patients responded well to ticarcillin and two failed to respond. Our study suggests that ticarcillin is useful in the treatment of anaerobic infections.

Usefulness of (1,3) ß-D-glucan detection in bronchoalveolar lavage samples in Pneumocystis pneumonia and Pneumocystis pulmonary colonization.

OBJECTIVE OF THE STUDY: Recent data demonstrate the usefulness of (1,3) ß-d-glucan (BG) detection in serum samples to distinguish patients developing Pneumocystis pneumonia and patients who are colonized by the fungus. In contrast, data of BG detection in bronchoalveolar lavage (BAL) samples from these patient populations are still rare. PATIENTS: In this context, we determined BG levels in BAL samples from 11 Pneumocystis pneumonia (PCP) patients, 10 colonized patients, and 24 Pneumocystis-uninfected patients. MATERIALS AND METHODS: BG levels were determined on each BAL sample using the Fungitell(®) kit (Associates of Cape Cod, Inc., Cape Cod, MA, USA) according to the manufacturer's instructions applied to serum sample examination. RESULTS: The BG levels in BAL samples from the PCP patient group (mean value 20 588 pg/mL) were significantly higher than those in the colonized patient group (mean value 105 pg/mL) (P=0.0001, Mann-Whitney test) and than those in the Pneumocystis-uninfected patient group (mean value 74 pg/mL) (P<0.0001, Mann-Whitney test). The BG levels in BAL samples from the colonized patient group did not differ significantly from those in the Pneumocystis-uninfected patients group (P=0.21). CONCLUSION: The results suggest that measurements of BAL BG levels may facilitate the differential diagnosis of PCP and pulmonary colonization with Pneumocystis.

Brain capillary perfusion during sleep.

Brain capillary perfusion was evaluated in the different states of the wake-sleep cycle-quiet wakefulness (QW), quiet sleep (QS), and active sleep (AS)-in rats. The extent of the perfused capillary network was determined by intravascular distribution of a fluorescent marker. Evans blue (EB); it remained unchanged across the three behavioral conditions, QW, QS, and AS. The anatomical network was assessed by alkaline phosphatase (AP) endothelial staining, which is known to underestimate the number of existing capillaries. The resulting number of AP profiles were, therefore, significantly lower than the number of EB profiles, but the percentage of AP-stained capillaries that were perfused (96%) was also unchanged across the behavioral conditions. The results indicate that no capillary recruitment accompanies the wake-sleep cycle. Capillary surface area is a relevant factor in determining exchanges across the blood-brain barrier. In the absence of capillary recruitment (relative constancy of the surface area), the CBF changes during sleep should preferentially affect flow-limited with respect to diffusion-limited transport.

Regulation of sleep and body temperature in response to exposure to cool and warm environments in neonates.

BACKGROUND AND OBJECTIVE: Thermoregulation is impaired during desynchronized sleep in animals and in adults. This can lead to a conflict between homeothermy and sleep in nonthermoneutral conditions. This study aimed to analyze thermoregulation during sleep, especially during desynchronized sleep (active sleep, AS) and to determine whether the conflict between thermoregulation and sleep might exist in the newborn sleeping in warm or cool conditions. METHODS: Esophageal and skin (cheek and abdomen) temperatures, local sweating rate (ventilated sweat collection capsule stuck on the abdomen), metabolism (indirect respiratory calorimetry), and sleep variables were recorded in 10 newborns exposed, in an incubator, to thermoneutral, warm, and cool environments. Body movements and apneas were also considered. Exposures were performed after a first habituation condition. RESULTS: Sleep structure was not modified by the first exposure nor by the warm environment. Exposure to cool temperatures increased AS duration (+13% of total sleep time) and the quantity of body movements during AS (+11.3% of AS duration), whereas these parameters were not modified during quiet sleep. The thermoregulatory response to warm and cool environments was not impaired during AS. During exposure to mild thermal load, analyses revealed large interindividual differences in the strategy for thermoregulation during AS. Depending on the newborn, the thermoregulatory response to cool temperatures could be described by an increase either in nonshivering thermogenesis or in frequency of body movement. In warm conditions, most newborns exhibited an increased sweating rate. The interindividual differences (lack of increase sweating in three newborns) seemed to be linked to changes in the sensitivity of the sweating response. CONCLUSION: Because thermoregulation is not impaired during AS, this sleep stage seems to be a well-protected one from a thermoregulatory point of view. This difference from adults and animals may be due to the important role of AS in newborn's nervous maturation.

Relative and combined effects of heat and noise exposure on sleep in humans.

In a counter-balanced design, the effects of daytime and/or nighttime exposure to heat and/or traffic noise on night sleep were studied in eight healthy young men. During the day, the subjects were exposed to baseline condition (ambient temperature = 20 degrees C; no noise) or to both heat (35 degrees C) and noise. The duration of the daytime exposure was 8 h ending 5 h before sleep onset. The following nights, the subjects slept either in undisturbed (20 degrees C; no noise) or in noise, heat, or noise plus heat-disturbed environments. During the day, the various types of traffic noise were distributed at a rate of 48/h with peak intensities ranging between 79 and 86 dB(A). The background noise level was at 45 dB(A). At night, the peak intensities were reduced by 15 dB(A), the rate was diminished to 9/h, and the background noise was at 30 dB(A). Electrophysiological measures of sleep and esophageal and mean skin temperatures were continuously recorded. The results showed that both objective and subjective measures of sleep were more disturbed by heat than by noise. The thermal load had a larger impact on sleep quality than on sleep architecture. In the nocturnal hot condition, total sleep time decreased while duration of wakefulness, number of sleep stage changes, stage 1 episodes, number of awakenings, and transitions toward waking increased. An increase in the frequency of transient activation phases was also found in slow-wave sleep and in stage 2. In the nocturnal noise condition, only total number of sleep stage changes, changes to waking, and number of stage 1 episodes increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of continuous heat exposure on sleep during partial sleep deprivation.

This study examined the effects of continuous heat exposure on sleep structure during a partial sleep-deprivation regime. The experimental protocol was divided into three periods. After a baseline period (5 days and nights at 20 degrees C), the sleep of the subjects was restricted to the second half of the night (3 a.m.-7 a.m.) for four consecutive nights. The restricted-sleep period was followed by two recovery days and nights. During the deprivation and recovery periods, the ambient temperature was 20 degrees C for six of the 12 subjects and 35 degrees C for the others. Sleep, esophageal and mean skin temperatures were continuously recorded. At 20 degrees C, the expected effect of sleep debt was apparent. There were significant reductions in time spent awake and in latencies for sleep and stage 4 sleep. The duration of stage 4 sleep significantly increased during the four successive restricted-sleep nights, whereas esophageal temperature significantly decreased over the successive days. When heat was added, esophageal temperature decrease was weakened, and the significant increase in stage 4 duration seen at 20 degrees C was not found. The findings suggest that the heat load imposed in our experimental condition has a suppressive effect on sleep stage 4 increase, which is induced by sleep restriction. The hypothesis that an increase in this sleep stage serves as a mechanism for energy conservation should be also considered.

Antimicrobial activity of antituberculosis agents against anaerobic bacteria.

Anaerobic infections may coexist with tuberculosis, and can be mistaken for one another. The effect of therapy with antituberculosis chemotherapeutic agents against anaerobic bacteria (with the exception of rifampin) is unknown. We therefore examined the in vitro efficacy of certain commonly used antituberculosis agents (rifampin, isoniazid, and ethambutol) against 370 strains of anaerobic bacteria, including 86 isolates of Bacteroides fragilis. Rifampin at a concentration of 2 microgram/ml inhibited 91 percent of all anaerobic isolates. Both ethambutol and isoniazid were totally ineffective against any of the anaerobes tested, even at 64 microgram/ml. Therapy with rifampin in an unsuspected anaerobic infection can be misdiagnosed for tuberculosis. Therefore, when tuberculosis is suspected, isoniazid and ethambutol can be used and rifampin withheld until the acid-fast bacilli are demonstrated by additional diagnostic procedures, such as transtracheal aspiration.

Tissue levels of doxycycline in the human lung and pleura.

Antibiotic concentrations in the human lung and pleural tissue were measured following intravenous administration of doxycycline. The average serum levels were 9.3, 7.0 and 3.0 micrograms/ml at 1, 2, and 3 hours; correspondingly, the lung tissue levels were 6.8, 3.5 and 2.3 micrograms/g. The pleural tissue antibiotic concentrations at the same time intervals were 2.5, 1.5, and 1.5 micrograms/g. This suggests that doxycycline is retained well by the lung and the pleura, well above the minimal inhibitory concentration of most of the common bacterial pathogens of the lung, and may be used in the treatment of lung infections caused by susceptible organisms.

Antimicrobial effect of amniotic fluid.

The antimicrobial effect of amniotic fluid (AF) obtained during the first (AF1) and second (AF2) trimesters was compared with the third (AF3) against anaerobic bacteria, such as Bacteroides fragilis ss. fragilis (6 strains), Eubacterium lentum (3 strains), and Peptostreptococcus anaerobius (4 strains). Escherichia coli (5 strains) served as a positive control. AF1 supported the growth of all 4 anaerobes (except B fragilis for 4 hours) for the entire 24-hour period tested. AF2 supported the growth of E coli and B fragilis for 24 hours but temporarily inhibited P anaerobius and E lentum. In contrast, AF3 inhibited all bacteria tested for 8 hours or more. It is concluded that AF1 is the least inhibitory, AF3 the most, and AF2 intermediate for the organisms tested. Lack of antimicrobial effect of AF on anaerobic bacteria may be one explanation for the higher incidence of anaerobic infections during absortion than during the prenatal period.

Assessment of dry heat exchanges in newborns: influence of body position and clothing in SIDS.

A dramatic decrease of sudden infant death syndrome (SIDS) has been noted following the issuance of recommendations to adopt the supine sleeping position for infants. It has been suggested that the increased risk could be related to heat stress associated with body position. In the present study, the dry heat losses of small-for-gestational-age newborns nude or clothed were assessed and compared to see whether there is a difference in the ability to lose heat between the prone and supine positions. An anthropomorphic thermal mannequin was exposed to six environmental temperatures, ranging between 25 and 37 degrees C, in a single-walled, air-heated incubator. The magnitudes of heat losses did not significantly differ between the two body positions for the nude (supine 103.46 +/- 29.67 vs. prone 85.78 +/- 34.91 W/m(2)) and clothed mannequin (supine 59.35 +/- 21.51 vs. prone 63.17 +/- 23.06 W/m(2)). With regard to dry heat exchanges recorded under steady-state conditions, the results show that there is no association between body position and body overheating.

Induction of iNOS in human monocytes infected with different Legionella species.

The contribution of nitric oxide (NO) radicals to the suppression of intracellular replication of Legionella has been well established in rodents but remained questionable in humans. Considering the fact that human monocytes do not exhibit a high-output NO production, we used sensitive methods such as detection of inducible NO synthase (iNOS) mRNA by reverse transcription-PCR and demonstration of iNOS protein expression by means of flow cytometry and Western blot to compare the levels of iNOS induced by Legionella species which, in accordance to their human prevalence, show different multiplication rates within human monocytic cells. The expression of iNOS in Mono Mac 6 (MM6) cells showed an only moderate inverse correlation to the intracellular replication rate of a given Legionella species in the protein expression assays. However, stimulation of host cells with 1,25-dihydroxyvitamin D(3) to enhance NO production and inhibition of NO production by treatment of host cells with N(G)-methyl-L-arginine were not able to modify the intracellular multiplication of legionellae within MM6 cells. Therefore, NO production does not seem to play a crucial role for the restriction of intracellular replication of Legionella bacteria within human monocytic cells. Rodent models in investigations which are supposed to clarify the involvement of NO radicals in defense mechanisms against Legionella infections in humans are of doubtful significance.