Biomedical subjects

L Marzio

Publications and source records attributed to L Marzio.

At least 19 recordsLinked to original sources

PubMed2001

Transmission of Helicobacter pyori in an animal model.

An experimental murine model was studied to evaluate the orogastrointestinal colonization of Helicobacter pylori and the animal-to-animal transmission. Balb/C mice were infected with H. pylori and housed with uninoculated mice in cages with and without a grate on the floor. Mice were killed after 7, 14, 30, and 45 days, and samples from the esophagus, stomach, small intestine, colon, and rectum were analyzed for H. pylori by PCR and immunohistochemistry and for histological changes. Bacterial colonization was assessed also by culture from stomach samples. H. pylori was cultured by stomach samples of infected mice at 7, 14, and 30 days. Using PCR and immunohistochemistry, H. pylori was detected in inoculated and uninoculated mice in all areas examined, with an high percentage of positive samples in the esophagus and stomach. Moreover transmission was detected, without differences, regardless of whether mice were housed with or without a grate on the floor, supporting an orooral animal transmission.

Animals↗

PubMed2001

Transient lower esophageal sphincter relaxations and gastroesophageal reflux episodes in healthy subjects and GERD patients during 24 hours.

Still little is known about the 24-hr pattern of transient lower esophageal sphincter relaxations (TLESRs), particularly in patients with GERD. The aim of our study was to evaluate the 24-hr esophageal and LES motor pattern and esophageal pH and to identify the relationship between TLESRs and gastroesophageal reflux in healthy subjects and in GERD patients. Ten healthy subjects and nine patients with esophagitis (grade I-II) underwent a 24-hr pH manometric recording by means of a portable electronic device. The recording aimed at identifying the temporal relationships between reflux episodes and LES motor events. The GERD patients showed a greater number of either reflux episodes or TLESRs during the 24 hr as compared to controls. While most refluxes occurred during TLESRs in both groups, a small percentage of TLESRs was followed by reflux episodes in healthy people, with only a slight increase in GERD patients. In conclusion, although representing an important motor pattern during gastroesophageal reflux both in healthy subjects and in patients with GERD, TLESR could probably be considered one of the pathophysiologic mechanisms of gastroesophageal reflux more than the primary cause of reflux episodes.

Adult↗

PubMed2001

Transient lower oesophageal sphincter relaxations play an insignificant role in gastro-oesophageal reflux to the proximal oesophagus.

Gastro-oesophageal reflux to the proximal oesophagus may cause atypical symptoms of gastro-oesophageal reflux disease (GORD). The motor abnormalities underlying reflux into the proximal oesophagus are still unclear. The aim of this study was to analyse the oesophageal motility during reflux into the proximal oesophagus in a group of healthy subjects and in patients with atypical symptoms of GORD. We concentrated particularly on lower oesophageal sphincter (LOS) activity and transient lower oesophageal sphincter relaxations (TLOSRs). Ten patients (7M, 3F, age 25-51 years) with mild oesophagitis (Savary-Miller grade I-II) and 10 healthy subjects (6M, 4F, age 23-54 years) underwent a 24-h dual pH-metric and manometric recording, using an electronic portable device. This recorded distal and proximal oesophageal pH values, oesophageal body and LOS motility. GORD patients had more distal and proximal reflux (DR and PR) compared with healthy controls (DR P < 0.001; PR P < 0.05). TLOSRs were the most frequent event during reflux into the distal oesophagus, whereas TLOSR frequency was much lower during reflux to the proximal oesophagus in GORD patients and in healthy controls (P < 0.05 and P < 0.01 vs. distal reflux, respectively). A significant relationship between TLOSRs and distal refluxes was present but no relationship with proximal reflux was detected. We conclude that TLOSRs are much less frequent during reflux to the proximal oesophagus than distal oesophageal reflux in patients with mild GORD suffering from atypical manifestations. The mechanism of acid reflux to the proximal oesophagus is unclear.

Adult↗

PubMed2001

Effect of hyoscine N-butylbromide on gastroesophageal reflux in normal subjects and patients with gastroesophageal reflux disease.

OBJECTIVES: Recent studies have shown that atropine reduces gastroesophageal reflux in normal subjects and patients with gastroesophageal reflux. The aim of the study has been to assess the effects of an atropine derivative, hyoscine N-butylbromide in normal subjects and patients with gastroesophageal reflux disease by recording esophageal and gastric pH-metry for a 24-h period. METHODS: Ten normal subjects and 10 patients with gastroesophageal reflux disease were evaluated. PH-metry was performed using two glass pH flexible probes with distal incorporated electrodes. The two catheters were introduced nasally under fluoroscopy. One probe was positioned in the gastric body; the other was placed 5 cm above the lower esophageal sphincter which had been evaluated manometrically before the study. Recording lasted without interruption for 48 h. Patients and normal subjects were assigned to receive hyoscine N-butylbromide (10 mg p.o. t.i.d.) for 24 h followed by a placebo for another 24 h or vice versa in a random manner. The pH was analyzed for a total number of acid refluxes and percentage of the period with pH <4 in the esophagus and the mean gastric pH in 24 h, before and after treatment with hyoscine N-butylbromide. RESULTS: The number of reflux episodes was significantly greater with hyoscine N-butylbromide in comparison with a placebo in patients with gastroesophageal reflux disease and normal subjects (p < 0.02). The percentage of time with pH <4, was also significantly greater in patients with gastroesophageal reflux disease and in controls (p < 0.05). The mean 24-h gastric pH after hyoscine N-butylbromide was not different from placebo in gastroesophageal reflux disease and controls. CONCLUSIONS: Hyoscine N-butylbromide, an anticholinergic agent, increases the total number of esophageal acid refluxes in patients with gastroesophageal reflux disease and in controls, therefore it is not recommended in the treatment of gastroesophageal reflux disease.

Adult↗

PubMed2000

Short- and long-term effect of glyceryl trinitrate (GTN) ointment 0.2% and 2% on anal canal pressure in patients with chronic anal fissures.

Controversial data are available on the duration of action of glyceryl trinitrate after acute and chronic application on anal canal pressure. Our aim was to assess the effect of glyceryl trinitrate at 0.2% and 2% on anal canal pressure before and after eight weeks of treatment. Anal canal pressure was evaluated in 12 patients with chronic anal fissures with an electronic probe with three recording sites before and after the application of glyceryl trinitrate, 120 mg on the external anal verge. Six patients received glyceryl trinitrate at 0.2% and six at 2%. Glyceryl trinitrate 0.2% and 2% equally reduce basal anal canal pressure in all three recording sites (P < 0.001) with major effect on the inner site of the canal toward the rectum, for a 60-min period. Eight weeks after application, the effect of glyceryl trinitrate was unchanged. In conclusion, glyceryl trinitrate ointment at 0.2% and 2%, equally reduces anal canal pressure for 60 min and this effect is kept unchanged after eight weeks of application.

Adult↗

PubMed2000

Role of antimicrobial susceptibility testing on efficacy of triple therapy in Helicobacter pylori eradication.

BACKGROUND: Helicobacter pylori treatment failure may be due to resistance to macrolides and 5-nitroimidazoles. AIM: To test whether a preliminary in vitro susceptibility test of H. pylori to tinidazole and clarithromycin and a consequent specific regimen could improve the eradication rate. METHODS: A total of 109 consecutive H. pylori-positive patients with dyspeptic symptoms were included. At endoscopy, biopsy from the antrum was obtained for H. pylori culture and antimicrobial susceptibility testing. Fifty-six patients were treated with omeprazole, tinidazole and clarithromycin for 10 days (group OTC) and 53 patients received therapy on the basis of the susceptibility test (group SUSC). Treatment success was evaluated by the 13C-urea breath test 1 month after the end of therapy. RESULTS: Eight patients dropped out. Overall primary resistance to clarithromycin, tinidazole and both antibiotics was 13%, 33% and 4%, respectively. In group OTC, H. pylori was eradicated in 81% and 75% of patients by per protocol and intention-to-treat analysis, respectively. Per protocol and intention-to-treat eradication rates for group SUSC were 98% and 91% (P < 0.05 vs. group OTC). CONCLUSIONS: These data show that in H. pylori infection, antibiotic therapy based on the results of culture and susceptibility testing gives, in comparison to standard therapy, a significant improvement in eradication rate.

Adult↗

PubMed2000

Gastric emptying of a solid-liquid meal measured with 13C octanoic acid breath test and real-time ultrasonography: a comparative study.

OBJECTIVES: The 13C octanoic acid breath test (OBT) has been proposed as a reliable noninvasive test to measure gastric emptying. OBT has been compared with scintigraphy; however, there are no data comparing it with gastric emptying measured with real-time ultrasonography (RUS) The aim of the study was to correlate gastric emptying of a solid-liquid meal, with OBT and RUS simultaneously evaluated in a group of normal volunteers. METHODS: A total of 14 normal subjects ingested a standard test meal (one scrambled egg with two slices of white bread, 10 g of butter, and 300 ml of tap water). The egg yolk was mixed with 0.1 ml of 13C octanoic acid. Breath samples for 13CO2 analysis were collected in breath bags and were analyzed by means of isotope-selective nondispersive infrared spectrometry (IRIS). RUS was simultaneously performed by calculating the antral area following a previous validated method. Breath samples and antral area were taken at baseline and every 15 min after the meal during the first 2 h and every 30 min for another 2 h. Lag time (Tlag) and gastric half emptying time (T(1/2)) were calculated for OBT and RUS. Data were analyzed by the Student's t test for paired data, correlation coefficient, and regression line. RESULTS: The results show a statistically significant longer Tlag and T(1/2) for OBT in comparison with RUS (p < 0.001). A significant correlation and positive regression line was computed between OBT and RUS for Tlag and for T(1/2). CONCLUSIONS: Our results show that OBT overestimates gastric emptying parameters of a solid-liquid meal in comparison with RUS. However, both techniques give data in good correlation. Because OBT is less operator-dependent than RUS, it may be useful in comparative gastric emptying studies.

Adult↗

PubMed1999

SR140333, a substance P receptor antagonist, influences morphological and motor changes in rat experimental colitis.

The etiology of inflammation, edema, and smooth muscle contraction characteristic of inflammatory bowel disease is not clearly understood. There is evidence that several neuropeptides, including substance P (SP), may play a role. In this study we evaluated the ability of a SP-antagonist (SR140333) to modify the course of experimental colitis induced in the rat by trinitrobenzene sulfonic acid (TNB). Colitis was induced in 24 rats using TNB applied by intrarectal enema. Twelve TNB-treated rats received SR140333, 0.1 mg/kg intraperitoneally, 30 min before the administration of TNB and every 48 hr until death. Twelve rats receiving only intrarectal 0.9% saline served as controls. Rats of each group were killed after 14 days. At day 14, the control group showed no signs of inflammation whereas the TNB-treated rats without SR140333 treatment exhibited a well-established colitis. The TNB-treated group had a higher level of inflammation, as seen histologically and by the significantly greater weight of colon strips, compared to the controls (0.30 +/- 0.09 g vs 0.13 +/- 0.03 g, P < 0.001) and to the SR140333-treated rats (0.30 +/- 0.09 g vs 0.14 +/- 0.05 g, P < 0.001). In addition, smooth muscle contractility was significantly reduced in the inflamed colons of TNB-treated rats when compared with the controls (carbachol: 42.7 +/- 20.3 vs 254.2 +/- 69.78 mg/mm2; SP: 18.5 +/- 10.02 vs 89.45 +/- 23.17 mg/mm2; KCl: 11.4 +/- 2.2 vs 98.32 +/- 33.57 mg/mm2, P < 0.01). However, SR140333-treated rats showed a recovery from inflammation and motor alterations caused by TNB (carbachol: 150.9 +/- 46.1 mg/mm2, P < 0.01; SP: 32.5 +/- 9.4 mg/mm2, P < 0.05; KCl: 125.7 +/- 36.1 mg/mm2, P < 0.01). In conclusion, treatment with SP antagonist SR140333 reduces the severity of colitis and has beneficial effects on the concomitant alterations of contractility. Thus, the blockade of substance P may represent a possibility in the treatment of intestinal inflammation.

Animals↗

PubMed1999

Evidence for an oral-faecal transmission of Helicobacter pylori infection in an experimental murine model.

An experimental murine model was used to evaluate the possible animal-to-animal transmission of Helicobacter pylori and the mechanism involved. Twenty-four Balb/C mice were infected with H. pylori type I strain culture and kept with 24 noninoculated mice to evaluate the possible transmission of the microorganism. Twelve inoculated mice were housed with 12 noninoculated mice in a grated cage (supporting an oral-oral transmission); the remaining inoculated and noninoculated mice were housed in another cage without grating on the floor (supporting a faecal-oral transmission). The bacterial colonization was assessed by culture and immunohistochemistry. The systemic antibody response to H. pylori and the histopathological changes were evaluated; controls were examined at 2, 4, 8, 12 weeks after the start of the experiment. Faecal samples were also collected from each mouse on the day before sacrifice, to assess the presence of H. pylori by culture and by immunohistochemistry. In the gastric mucosa of inoculated mice, histopathological changes were recorded at each control time and H. pylori was detected both by immunohistochemistry and by a systemic antibody response; the microorganism was also cultured at 2, 4, 8 weeks postinoculation. H. pylori was detected in noninoculated mice, housed in the cage without grating, using an immunoperoxidase technique at 2, 4, 8 weeks after starting the experiment, and these positive values were supported by histopathological changes, and, in one case, at 8 weeks, also by the serum immune response. No colonies of H. pylori were detected by culturing faecal samples from either noninoculated or inoculated mice. The results obtained in this study seem to support an oral-faecal route as the mode of transmission of H. pylori infection in this animal model.

Animals↗

PubMed1998

Relationship between anal canal diameter and pressure evaluated simultaneously by endosonography and manometry in normal human subjects.

The study investigated the relationship between anal canal size and anal canal pressure measured simultaneously by anal endosonography and an electronic pressure probe. Twelve normal subjects were studied. Anal endosonography was performed using a 7.5-Mhz rotating transducer of 2-5 cm focal length covered with a sylastic balloon filled with degassed water (25 ml). During anal endosonography an electronic manometric probe was passed along the side of the probe and positioned in the anal canal. The ultrasonic image was frozen when maximal anal pressure was seen at basal, squeeze, and minimal pressure during straining. An image was also obtained at maximal anal relaxation after rectal distension with a balloon filled with 150 ml air. The results showed that anal canal pressure was significantly and linearly correlated with anal canal diameter (P < 0.001).

Anal Canal↗

PubMed1998

Proximal and distal gastric distension in normal subjects and H. pylori-positive and -negative dyspeptic patients and correlation with symptoms.

Aim of the study was to analyze gastric distension with water in H. pylori-positive and -negative dyspeptic patients and normal subjects and the correlation with symptoms. Twenty dyspeptic patients and 19 normal subjects were studied. H. pylori was determined in each dyspeptic patient with the rapid urea test at endoscopy. Gastric distension was evaluated by real-time ultrasonography with the ingestion of stepwise-increasing amounts of water up to a total of 600 ml. During distension, the symptom score was evaluated as well. The proximal stomach was significantly smaller in dyspeptic patients than in healthy controls, at 100-600 ml water (P<0.01). A larger distal stomach was observed at 500 and 600 ml of water (P<0.01). The score of bloating and fullness was greater in dyspeptics than in controls at 300 and 600 ml of water distension. The symptoms score was linearly correlated with proximal and distal gastric measurements in dyspeptic patients and in controls. No significant difference was found in dyspeptic patients regarding the H. pylori status. In conclusion, dyspeptic patients show a defective adaptation of the whole stomach to water distension and an increased symptom perception score as compared to controls. H. pylori infection does not seem to be a determining factor in these observed findings.

Adult↗

PubMed1998

Ranitidine bismuth citrate with either clarithromycin 1 g/day or 1.5 g/day is equally effective in the eradication of H. pylori and healing of duodenal ulcer.

BACKGROUND: No randomized double-blind studies have been performed to compare clarithromycin 1 g/day with higher doses of the macrolide (1.5 g/day) when combined with ranitidine bismuth citrate (RBC). AIM: To compare H. pylori eradication and ulcer healing rates of RBC 400 mg b.d. for 4 weeks combined for the first 2 weeks either with clarithromycin 500 mg b.d. (Group A) or clarithromycin 500 mg t.d.s. (Group B). METHODS: Two hundred and seventy-three patients with H. pylori-positive active duodenal ulcer were included. H. pylori infection was detected by CLO-test and histology on antral and corpus biopsies before and at least 4 weeks after the end of therapy. Eradication was assumed if both CLO-test and histology results were negative for H. pylori. RESULTS: Eradication/healing rates according to intention-to-treat and per protocol analysis were 76/82% and 87/92% for Group A and 78/85% and 88/95% for Group B, respectively (P = N.S.). Adverse events were reported by 7% and 12% of patients in Groups A and B, respectively, and they were generally mild. CONCLUSIONS: RBC in co-prescription with clarithromycin 500 mg b.d. is as effective as RBC plus clarithromycin 500 t.d.s. in eradicating H. pylori and healing duodenal ulcers.

Adolescent↗

PubMed1998

Swallows, oesophageal and gastric motility in normal subjects and in patients with gastro-oesophageal reflux disease: a 24-h pH-manometric study.

BACKGROUND: the motor aspects underlying gastro-oesophageal reflux disease (GORD) are still not completely clear. AIM: to evaluate the relationship between oesophageal and gastric motility in GORD patients. PATIENTS: twelve patients with grade I-II oesophagitis, mean age 45 yr, and 10 healthy subjects, mean age 42 yr, were studied. METHODS: a pH-manometry was performed to analyse oesophageal and gastric motility, swallows and oesophageal pH values for the whole 24-h period, and for the 2-min period before and after each reflux episode. RESULTS: as compared to controls, GORD patients showed in the 24-h period, a greater number of swallows (P < 0.01) and a lower percentage of post deglutitive propagated oesophageal body waves (P < 0.05). The number of migrating motor complexes (MMC) was similar in the two groups, with a lower amplitude of phase III gastric waves in GORD. During MMC reflux episodes were seen only in GORD patients. After refluxes an increase in swallows, simultaneous and secondary oesophageal waves were detected in GORD patients, with a reduction of primary peristalsis. Isolated gastric contractions preceded reflux episodes more frequently in GORD patients than in controls. CONCLUSIONS: GORD patients showed an increase in swallows with altered post-deglutitive oesophageal motility and a reduced amplitude of gastric MMC. Moreover small contractions of gastric antrum are present before acid refluxes, suggesting a multifactorial pathogenesis of the disease.

Adult↗

PubMed1998

Anti-Helicobacter pylori specific antibody immunohistochemistry improves the diagnostic accuracy of Helicobacter pylori in biopsy specimen from patients treated with triple therapy.

OBJECTIVE: To investigate the effectiveness of immunohistochemical technique to detect Helicobacter pylori (H. pylori) in patients treated with triple therapy. METHODS: Forty patients (18 men, 22 women, mean age 43 years) with active antral gastritis, H. pylori positive at urease test, culture, and histology, were treated for 1 wk with omeprazole, amoxicillin, and metronidazole. Gastritis was scored according to Sydney criteria. Two months after the end of therapy, endoscopy, urease test, culture, and histology were repeated. RESULTS: Culture and histology were negative in 32 (80%) of treated cases. Biopsy specimens of the eradicated group were stained with immunohistochemical technique using an anti-H. pylori specific polyclonal antibody. In 12 of 32 (37.5%) patients, clusters of round or vibrio-shaped bacteria, unidentified at histology, were stained by the specific anti-H. pylori antibody. After triple therapy, at histology all patients were found with improved gastritis. In six patients however, mucosal-associated lymphoid tissue (MALT) appearance, present before therapy, persisted after therapy. In five of six patients with MALT, immunostaining with anti-H. pylori antibody was positive. CONCLUSIONS: The immunohistochemical technique is more accurate than classical methods in identifying H. pylori after specific therapy. This method should, therefore, be used in all studies that aim to achieve eradication. Whether the H. pylori identified at immunohistochemistry is able to reactivate and induce recrudescence of infection remains to be clarified.

Adult↗

PubMed1996

Relationship between gastric and gallbladder emptying and refilling in normal subjects and patients with H. pylori-positive and -negative idiopathic dyspepsia and correlation with symptoms.

Gastric and gallbladder emptying and refilling was studied in 10 normal subjects and in 38 dyspeptic patients. H. pylori was determined in each dyspeptic on mucosal antral biopsy performed during endoscopy. Gastric and gallbladder emptying was evaluated by real-time ultrasonography. Normal subjects were evaluated after two solid-liquid meals of 340 kcal and 680 kcal. Dyspeptics were studied after the 340-kcal meal only. For each subject and patient, minimum gallbladder volume and percentage of gastric emptying at this point was determined. Gastric and gallbladder slope was also drawn, and the crossing point between the two slopes identified. In normal subjects with the 340-kcal and 680-kcal meal, minimum gallbladder volume occurred for a similar percentage of gastric emptying. The crossing point between the two slopes was computed at the same percentage of gastric and gallbladder refilling with both meals. With the 680-kcal meal, however, peak gallbladder contraction and the crossing point between the two slopes occurred significantly later than with the 340-kcal meal (P < 0.05). In dyspeptics with the 340-kcal meal, the parameters evaluated were similar to the ones computed in controls after the meal of 680-kcal, suggesting delayed gastric emptying and gallbladder refilling. The presence or absence of H. pylori and symptom score were not correlated with any of the parameters studied.

Adult↗

PubMed1996

Increase of swallows before onset of phase III of migrating motor complex in normal human subjects.

The aim of our study was to analyze the relation between the deglutitive activity and fasting esophageal and gastric motility in normal subjects. Fifteen healthy subjects (9 males, 6 females) with a mean age of 42 years (range 19-65) were studied. A 24-hr pH-manometric recording was performed using a probe with four solid-state recording sites 10 cm apart, placed so as to record the motor activity of esophageal body, lower esophageal sphincter (LES) or distal part of the esophagus, and gastric antrum. An additional probe with one recording site was placed in the pharynx to evaluate swallowing. A pH electrode was also placed at 5 cm above the sphincter. Data were transferred to a personal computer and analyzed using specific software. Subjects received two meals during the recording session. MMCs were almost exclusively recorded during the nighttime. A mean of 2 +/- 0.94 (SD) MMC per subject was detected with a mean (+/- SD) interval, between each cycle, of 86.11 +/- 34.53 min. During the 30 min preceding gastric phase III, the number of swallows showed an increase that reached statistical significance 5 min before the onset of phase III. A similar pattern was observed for the area under the curve (AUC) of the esophagus and LES. In conclusion deglutition and esophageal motility vary with the MMC, suggesting that the deglutitive activity is part of the interdigestive motility pattern.

Adult↗

PubMed1996

Effect of nitric oxide on propagated clusters of spontaneous motor waves in an ex vivo rabbit intestinal preparation.

The aim of this study was to determine whether nitric oxide can play a role in regulating the propagation of spontaneous motor activity in a rabbit intestinal preparation completely excluded from any central and vascular connection. Experiments were done on nine rabbits of either sex, weighing 2.5 +/- 0.5 kg (mean +/- SD). After one week of semiliquid diet the animals were sacrificed and a segment including the stomach, duodenum and part of the jejunum was removed and placed into a single chamber organ bath containing 1 L of oxygenated Krebs' solution. Four strain gauges connected to a Dynograph Recorder were sutured on the serosal surface 10 cm apart starting from the gastric antrum to the distal duodenum. Once the motor activity was stabilized, N-nitro-L-arginine methyl-ester (L-NAME) was added to the bath at increasing concentration from 10(-7) to 10(-4) M. Spontaneous motor activity was recorded, characterized by the cycling occurrence of bursts of waves, starting from the stomach and propagating to the descending duodenum. L-NAME at higher concentrations reduced the time interval between the bursts of waves with a concomitant increase in the propagation velocity of the motor activity. No change in the frequency of waves was detected. The effect of L-NAME was prevented by the administration of L-Arginine. This study suggests an important role for the nitric oxide pathway in the distal propagation of the spontaneous motor activity of the alimentary tract.

Animals↗

PubMed1995

Cigarette smoke, ferritin, and lipid peroxidation.

Gas and tar phases of commercially available filter cigarettes were tested for ferritin-iron-releasing effects and polyunsaturated-fatty-acid oxidant capacity in vitro. A vacuum pump-dependent apparatus with Cambridge filters was used to separate gas and tar; the former was directly smoked into reaction mixtures, while the latter was extracted from Cambridge filters in aqueous medium and freshly used at 40 to 80% final concentrations. Both phases induced ferritin iron release, which was not antagonized by superoxide dismutase (SOD). In specific experiments, we have also shown that gas and tar extracts could cross an organic (i.e., chloroform)-phospholipid layer before mobilizing ferritin iron. Once delocalized from ferritin, iron could trigger lipid peroxidation; however, a marked prooxidant effect (inhibited by 20 microM deferoxamine mesylate and significantly decreased by 40 microM vitamin E) was observed only with gas, whereas tar extracts showed antioxidant effects. Accordingly, tar extracts could also antagonize lipid peroxidation driven by non-chelated iron or by peroxyl radicals. In the absence of ferritin, gas-induced lipid peroxidation was very low, and tar extracts were apparently ineffective. Thus, the intrinsic lipoperoxidative capacity of cigarette smoke is low and is due to gas; however, when smoke interacts with ferritin, a marked iron-driven peroxidation becomes manifest essentially with gas, tar components acting as antioxidants. The present data suggest that cigarette-smoke-mediated iron mobilization from ferritin may represent a specific prooxidant mechanism related to cigarette smoking in vivo.

Atmosphere Exposure Chambers↗