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Biomedical subjects

A Sanna

Publications and source records attributed to A Sanna.

At least 55 records · Page 3Linked to original sources
PubMed1996

Expiratory flow limitation during sleep in heavy snorers and obstructive sleep apnoea patients.

Inspiratory flow limitation (FL) during sleep has previously been reported both in obstructive sleep apnoea (OSA) patients and heavy snorers (HS). Recent results from this laboratory have shown the occurrence both of inspiratory and expiratory flow limitation during muscular relaxation in awake healthy subjects and OSA patients. In this study, we have investigated whether expiratory flow limitation occurs during sleep in heavy snorers and in patients with OSA. We studied four nonapnoeic, heavy snorers and five OSA patients. Airflow was measured with a pneumotachograph attached to a tight-fitting mask, and supraglottic pressure with a catheter placed at the supraglottic level. Scoring for flow limitation was achieved by visual inspection of 200 breaths recorded during sleep. About 20% of the respiratory cycles presented isolated inspiratory flow limitation. Approximately the same percentage was observed in heavy snorers and OSA patients. Isolated expiratory flow limitation was less frequently recorded. Coupled inspiratory and expiratory flow limitations were more numerous, especially in heavy snorers. We conclude that both in heavy snorers and obstructive sleep apnoea patients, inspiratory flow limitation is associated with expiratory flow limitation. This suggests that upper airway obstruction during sleep is both an inspiratory and expiratory event.

Adult↗
PubMed1995

Enhancement of acetylcholine release by flumazenil in the hippocampus of rats chronically treated with diazepam but not with imidazenil or abecarnil.

The effects of long-term treatment (three times a day for 3 weeks) with pharmacologically active doses of the novel anxiolytics and anticovulsants abecarnil (0.5 mg/kg, IP) and imidazenil (0.5 mg/kg, IP) on basal hippocampal acetylcholine release in freely moving rats were compared with those of diazepam (3 mg/kg, IP). Challenge doses of diazepam, abecarnil, and imidazenil decreased the extracellular acetyl-choline concentration in the hippocampus by the same extent in animals chronically treated with the respective drug or vehicle. Moreover, the abrupt discontinuation of long-term treatment with diazepam, abecarnil, or imidazenil failed to affect hippocampal acetylcholine release during the first 5 days of withdrawal. In contrast, the acute administration of the benzodiazepine receptor antagonist flumazenil (1 mg/kg, IP) 2 days after diazepam withdrawal elicited a marked increase (65%) in acetylcholine release in the hippocampus. Flumazenil failed to induce the same effect 5 days after diazepam withdrawal or 2 or 5 days after discontinuation of long-term treatment with abecarnil or imidazenil. These results indicate that (i) the inhibitory effects of full (diazepam), partial (imidazenil), and selective (abecarnil) benzodiazepine receptor agonists on acetylcholine output in rat hippocampus are not affected by repeated drug administration; (ii) discontinuation of long-term treatment with each type of agonist does not affect hippocampal cholinergic mechanisms; and (iii) flumazenil increases acetylcholine release only in the hippocampus of rats chronically treated with diazepam. Together, these data further differentiate the pharmacology of benzodiazepine receptor full agonists from that of partial and selective agonists.

Acetylcholine↗
PubMed1995

Expiratory supraglottic obstruction during muscular relaxation.

Some reports have suggested occurrence of expiratory upper airway narrowing in patients with obstructive sleep apnea (OSA) during sleep and in awake humans during respiratory muscles relaxation. This is compatible with the hypothesis that upper airway muscles are activated during expiration. We studied five healthy volunteers and four patients with OSA in a tank respirator (Emerson; Cambridge, Mass). Supraglottic pressure (Psg) was measured with a catheter with the tip at the retroepiglottic level, tidal volume with an inductance plethysmograph and airflow with a pneumotachograph at the mouth. Diaphragmatic electromyogram was recorded with an esophageal bipolar electrode. Measurements were done at -30 cm H2O. Subjects were asked to breathe in phase with the respirator and then asked to breathe in phase with the respirator and then to relax their muscles. During muscular relaxation, there was supraglottic obstruction and flow limitation. This was observed during both inspiration and expiration. Upper airway obstruction was more severe in patients with OSA than in healthy subjects. In two healthy volunteers, fiberoptic bronchoscopy showed a wide-open oropharyngeal isthmus during active breathing that narrowed during muscular relaxation. This was true during both inspiration and expiration. We conclude that muscular relaxation is associated with upper airway narrowing and flow limitation occurring during both inspiration and expiration. We suggest that to preserve an open upper airway, airway muscles have to be activated during both inspiration and expiration.

Adult↗
PubMed1995

CMV-antigenemia after allogeneic bone marrow transplantation: correlation of CMV-antigen positive cell numbers with transplant-related mortality.

One hundred and thirty-four consecutive patients undergoing HLA-identical BMT were prospectively followed on a weekly basis for the development of CMV antigenemia (CMVAg-emia). End-points of the study were (1) incidence, (2) risk factors, and (3) predictive effect on transplant-related mortality (TRM). Fifty-six patients developed CMVAg-emia between day 8-366 (median 40) with an overall actuarial risk of 43%. The median number of positive cells a diagnosis was 4 (range 1-48) the median maximum number was 6.5 (range 1-435). Positive cells are expressed as number/2.5 x 10(5) cells. In multivariate analysis, T cell depletion (TCD) (RR 2.9, P = 0.0009) and acute graft-versus-host disease (RR 2.1, P = 0.01) were the two risk factors predictive for CMVAg-emia. The risk of developing CMV-IP was significantly higher in patients with, as compared to patients without, CMVAg-emia (P = 0.0005) and occurred mostly in patients who received TCD marrow (P = 0.0009) despite treatment with gancyclovir or foscarnet at the time of CMVAg-emia. TRM was 24% in patients not developing CMVAg-emia; it was 21 and 47% in patients with "4" positive cells at diagnosis of CMV (P = 0.008), and 12 vs 54% for patients with "6" positive cells during infection (P = 0.0003). Both were predictive of TRM in multivariate analysis (P = 0.04 and P = 0.002). In conclusion, the risk of developing CMVAg-emia post-allo BMT is influenced by the marrow T cell content and by the occurrence of acute GVHD. High numbers of CMV antigen positive cells are associated with considerable transplant-related mortality, and may therefore identify patients eligible for early aggressive therapy.

Adolescent↗
PubMed1994

Bronchodilator effect of inhaled nitric oxide in healthy men.

Studies in animals have shown that inhalation of nitric oxide (NO) either reduced pulmonary resistance after an induced bronchospasm or protected animals from bronchoconstriction. To evaluate whether NO inhalation (80 parts per million) influences basal bronchial tone or reverses methacholine-induced bronchospasm, we determined specific airway conductance (SGaw) as a measure of airway caliber in seven healthy men. After methacholine-induced bronchoconstriction NO increased SGaw by 23% (p < 0.05). One week later, NO inhalation did not change baseline SGaw values. However, albuterol inhaled after NO, or on a separate day, significantly increased SGaw (p < 0.05). The bronchodilator effect of NO in men with methacholine-induced bronchospasm is much less than that reported in animals or that regularly observed in asthmatic patients after the inhalation of beta-sympathomimetic drugs.

Administration, Inhalation↗
PubMed1994

Contraction and relaxation of upper airway muscles during expiratory application of negative pressure at the mouth.

Upper airway muscles (UAM) are activated during inspiration, but little is known about their activity during expiration. We studied six healthy volunteers in supine position. Negative pressure (-10 to -30 cm H2O) was applied cyclically at the mouth during expiration. Subjects actively breathed during inspiration and either contracted or relaxed their UAM during expiration. Supraglottic pressure (Psg) was measured with a catheter with the tip at the supraglottic level. During relaxation, but not during contraction, there was expiratory flow limitation (FL) accompanied by high frequency pressure and flow oscillations (70 +/- 5.7 Hz at -30 cm H2O). The average linear supraglottic resistance was higher during relaxation than during contraction at both -10 and -20 cm H2O (p < 0.05), but not at -30 cm H2O. Amplitude of expiratory genioglossus electromyogram was 3.6 +/- 2.5 mm during quiet breathing, 7.0 +/- 3.8 mm during contraction (p < 0.05) and 4.1 +/- 1.8 mm during relaxation. Average mouth pressure, which immediately preceded pressure (and flow) oscillations was -2.1 +/- 0.9 cm H2O. In one subject cineradiography of the neck during expiratory application of -30 cm H2O showed anterior flexion and high frequency oscillations of the soft palate during relaxation. During contraction, the soft palate was close to the posterior pharyngeal wall without oscillations. We conclude that cyclically applied negative pressure at the mouth during expiration produced expiratory flow limitation during relaxation but not during contraction, and that expiratory contraction of UAM stabilizes upper airways during negative pressure application at the mouth.

Adult↗
PubMed1994

[A transesophageal Doppler echo-color study of pulmonary venous flow before and after the correction of valvular defects].

AIM OF THE STUDY: To verify changes of pulmonary venous flow pattern before and after surgical or percutaneous correction of valvular heart disease. METHODS: The pulmonary venous flow pattern was studied by transesophageal echocardiography in 27 patients affected with heart valve disease (11 mitral insufficiency, 10 mitral stenosis, 2 aortic stenosis and 4 pulmonary stenosis), before and after surgical or percutaneous correction. Pulmonary venous flow velocity variables measured included peak systolic and diastolic flow velocities (VmaxS and VmaxD), systolic and diastolic velocity time integrals (IS and ID) and their respective ratios (VmaxS/VmaxD and IS/ID). Paired Student's t-test was used for analysis of data; a p value < 0.05 was considered statistically significant. RESULTS: In mitral stenosis and insufficiency, as well as in pulmonary stenosis, the VmaxS/VmaxD and IS/ID ratios were constantly < 1. Aortic stenosis, on the contrary, showed a normal preoperative pattern of pulmonary venous flow, which did not change after correction. All other successful corrections (17 surgeries, 4 angioplasties) were characterised by an increase of VmaxS/VmaxD and IS/ID ratios. (Mitral stenosis: VmaxS/VmaxD 0.80 +/- 0.31 vs 1.4 +/- 0.5, p = 0.006; IS/ID 0.86 +/- 0.77 vs 1.62 +/- 0.62, p = 0.016. Severe mitral insufficiency: VmaxS/VmaxD -0.71 +/- 0.32 vs 1.19 +/- 0.32, p < 0.0001; IS/ID 0.41 +/- 0.19 vs 1.04 +/- 0.31, p = 0.006. Moderate mitral insufficiency: VmaxS/Vmax D 0.38 +/- 0.04 vs 0.95 +/- 0.06, p = 0.001; IS/ID 0.32 +/- 0.05 vs 0.95 +/- 0.07, p = 0.02. Pulmonary stenosis: VmaxS/VmaxD 0.43 +/- 0.23 vs 1.09 +/- 0.35, n.s. e IS/ID 0.49 +/- 0.34 vs 0.92 +/- 0.65, n.s.). Failure to return to a normal pulmonary venous pattern was observed in the 2 cases of partially successful mitral valvuloplasty (one of which was subsequently transformed into a mitral valve replacement with immediate normalisation of the pattern) and in the 2 cases of incomplete relief of a pulmonary stenosis after pulmonary valvuloplasty. CONCLUSIONS: Though preliminary, these observations suggest a high sensitivity of this method and, therefore, a possible role of pulmonary venous pattern studies in the assessment of the efficacy of treatment in mitral and pulmonary valve disease.

Adolescent↗
PubMed1993

Usefulness of transesophageal echocardiography in the pediatric catheterization laboratory.

Transesophageal echocardiography was performed in 51 children (aged 2 to 14 years, mean 4; weight 9 to 50 kg, mean 21) undergoing elective diagnostic or therapeutic cardiac catheterization. The interventional procedures were percutaneous balloon dilation of pulmonary (n = 8) and aortic (n = 2) valve stenosis, percutaneous closure of patent ductus arteriosus (n = 8), and attempted occlusion of Pott's anastomosis by the double umbrella device (n = 1). The diagnostic catheterizations were performed on preoperative children of whom 5 had undergone previous palliative procedures. Precise placement of the balloon across the valve, timing of balloon inflation and deflation according to real-time monitoring of ventricular function and immediate evaluation of results and complications were accomplished with transesophageal monitoring. The exact position of distal and proximal umbrellas of patent ductus occlusive devices was checked on transesophageal imaging and completeness of occlusion controlled on color Doppler. The only relevant information in the preoperative cases was the detection of a septic thrombus in a severely ill patient. With more experience and smaller probes, transesophageal echocardiography may become a new method of monitoring cardiac catheterization also in smaller children where it may reduce duration of the procedure and amount of contrast material.

Adolescent↗
PubMed1993

Upper airway obstruction induced by negative-pressure ventilation in awake healthy subjects.

Negative-pressure ventilation (NPV) induces sleep-related upper airway obstruction. However, the precise mechanism and site of upper airway obstruction during NPV have not been worked out. We studied seven awake healthy volunteers (23-30 yr old) in an Emerson tank respirator. Subjects had the head outside the iron lung and breathed through a pneumotachograph, which yielded the airflow (V) signal. Supraglottic pressure (Psg) was measured with a catheter with the tip at the retroepiglottic level. Diaphragmatic electromyograms (EMGdi) were obtained from an esophageal bipolar electrode. Tidal volume was measured with an inductance plethysmograph. Measurements were done at -10, -20, and -30 cmH2O. At each pressure run subjects were asked to repeatedly relax or to actively breathe in phase with the respirator. Subjects had been previously trained to relax during NPV. During the relax runs there was no EMGdi activity. Stridor or wheezing occurred in all seven subjects during the relax runs but not during the active runs. Two patterns were associated with NPV during relax runs. One pattern was decreases in both V and Psg followed by zero values of these indexes, which corresponded to an inspiratory narrowing and closure of the glottis. These changes were visualized by fiber-optic bronchoscopy in one subject. The second pattern was a decrease in V and increase in Psg, which corresponded to an inspiratory supraglottic obstruction. In five subjects a supraglottic pattern was observed, whereas in two subjects glottic closure was seen. We conclude that muscular relaxation during NPV produces a decrease in the caliber of the upper airways at the glottic or supraglottic level. An uncoupling of upper airway muscle activity and the diaphragm might be the mechanism responsible for these changes.

Adult↗
PubMed1992

Chlamydial genital infections and laparoscopic findings in infertile women.

Several studies have shown that previous chlamydial genital infection, reflected by serological markers, is strongly associated with tubal damage leading to tubal infertility. In 105 women undergoing laparoscopy, multiple samples were collected from the lower (urethra and cervix) and upper (endometrium, peritoneal fluid, tubal lumen) genital tract, in order to isolate Chlamydia trachomatis in cell culture. Chlamydia trachomatis was isolated from at least one site in 13 (30.9%) of 42 infertile women with tubal infertility, in 5 (12.1%) of 41 women with unexplained infertility, in 1 of 4 women affected by acute salpingitis and in 1 (5.5%) of 18 women with endometriosis or uterine malformations. The latter group was the control group. Thirteen (65%) of the 20 positive women harboured Chlamydia trachomatis in their upper genital tract alone and 16 women were positive in one or both tubes. Only one of the positive women showed laparoscopic signs of acute pelvic infection. Four of the 5 positive women with unexplained infertility harboured Chlamydia trachomatis in the tubal lumen. This study confirms that chlamydial infection is strongly associated with tubal damage. It suggests that cervical cultures are inadequate for excluding a tubal infection and that chlamydial colonization of the tubal mucosa is possible in the absence of symptoms and laparoscopic signs of active infection.

Adult↗
PubMed1992

Cutaneous venom of Bombina variegata pachypus (Amphibia, Anura): effects on the growth of the human HL 60 cell line.

The effects of Bombina variegata cutaneous venom (Bvv) on eukaryotic cell growth has been assessed employing the human leukaemic cell line HL 60, by liquid and agar semisolid cultures and 51Cr release assay. HL 60 cells growth is impaired by Bvv in a dose-dependent fashion in both culture systems. The arrest of proliferation requires a contact time lower than 3 min and it is not reversed by washing and culturing the cells in a Bvv-free medium. Similarly, an extremely short exposure time is needed to determine maximum 51Cr release. Neither the agar medium nor the fetal calf serum interact with Bvv effects, which, according to the above findings, must be regarded as cytolytic in nature. In both liquid and the agar-semisolid culture Bvv cytolytic activity half life is about 8 hr. The cytolytic properties of Bvv are thought to be part of the chemical defence system of amphibian skin.

Amphibian Venoms↗
PubMed1991

[Value of monitoring of tracheal respiratory sounds in the diagnosis of nocturnal respiratory dysrhythmias].

Twenty-six patients underwent a polysomnigraphic study allowing sleep staging and respiratory events scoring with the use of the oronasal flow, abdominal, thoracic and total displacement (Respitracet), and ear oximetry. Moreover the patients were also equipped with a tracheal microphone giving a power rectified envelope (sonospirogram). Eleven patients showed abnormal respiratory events that were scored by visual lecture using all respiratory parameters (excluding the sonospirogram) and were classified as obstructive central and mixed apneas-hypopneas. Periodic breathing was also appreciated. Detection of the same events was tried with the sonospirogram alone. The sonospirogram could accurately detect snoring and periodic breathing and finally central obstructive mixed apnea (the apneic index being well correlated: p less than 0.001 as well as the mean apnea duration: p less than 0.005). In contrast hypopneic events related to snoring could not be accurately appreciated. We conclude that a sonospirogram may be useful for the detection of abnormal respiratory events when used alone (screening) as when added to other respiratory signals.

Adult↗
PubMed1991

Control of breathing in patients with chronic pulmonary obstructive disease: response to bamiphylline.

In two groups (A and B) of patients with severe chronic obstructive pulmonary disease (COPD), matched for age and routine pulmonary function testing, we evaluated inspiratory muscle strength (MIP), breathing pattern, mouth occlusion pressure (P0.1), inspiratory neural drive, assessed in terms of electromyographic activity of both diaphragm (EMGd) and intercostal (EMGint) muscles, and P0.1/EMGd ratio, an index of inspiratory neuromuscular coupling. Group A (8 patients) was studied before and after a 7-day period of a new oral xanthine derivative (bamiphylline, 1.2 g daily), and group B (7 patients) was given a placebo. Under control conditions, compared with an age-matched normal control group, groups A and B both exhibited a decrease in MIP, more rapid (increase in respiratory frequency RF) and shallower (decrease in tidal volume; VT) breathing (RSB), a marked increase in both EMGd and EMGint and a lower P0.1/EMGd ratio. With bamiphylline FEV1 and PaO2 significantly increased, while a substantial increase in MIP was found in 5 out of the 8 patients. VT and inspiratory time (Ti) also significantly increased, and RF decreased. Both EMGd and EMGint significantly decreased, whereas P0.1/EMGd exhibited a substantial increase in 5 out of the 8 patients. Conversely, no significant changes were observed in group B during the study period. From these data we conclude that in patients with COPD, clinical manifestations, probably associated with inspiratory muscle overloading (decrease in muscle strength, RSB, increase in respiratory neural drive, and derangement in neuromuscular coupling) may benefit from a short-term treatment with bamiphylline.

Aged↗
PubMed1991

[Echocardiography-guided endomyocardial biopsy].

We have performed 20 echocardiography-guided endomyocardial biopsies in 16 patients, totalling 98 bioptic samples. In each case fluoroscopy was available to supplement the echocardiographic findings. The right ventricle was biopsied in 17 cases, the left ventricle in 3. All 3 left ventricular biopsies and 14 out of 17 right ventricular biopsies were satisfactorily guided by echocardiography. An adequate echocardiographic window was not obtained in 3 cases of right ventricular biopsies and the procedures were carried out under fluoroscopy. In 5 cases (25%), totalling 10 samples, echocardiography showed a somewhat different position of the bioptome from that suggested by fluoroscopy, thus guiding a significant repositioning of it. Finally, in one patient, echocardiography promptly visualized a severe pericardial effusion, due to cardiac perforation, thus allowing its immediate drainage.

Adult↗
PubMed1991

[Contribution of polysomnography in the assessment of patients with chronic obstructive bronchopneumopathy].

15 COPD patients underwent a polysomnographic study demonstrating poor quality of sleep, a mean of SAO2 of 88.8 +/- 3.9% and a apneic-hypopnea index (AHI) of 5.7 +/- 11.8. AHI was higher in sleep stages I and II than in REM sleep. SAO2 showed a progressive drop when going from an awake stage to REM sleep. Respiratory events responsible for the most important desaturation where mostly observed in REM sleep and corresponded in 8 patients to obstructive events (overlap syndrome). The lower mean SAO2 in REM probably explains the best the importance in desaturation related to the respiratory events (Hb dissociation curve). Ear oximetry recordings however interesting are not able to quantify and recognise correctly the respiratory events. Therefore a polysomnographic study remains necessary in order to diagnose adequately the overlap syndrome.

Electrophysiology↗
PubMed1990

Mortality rate and prognostic indices in 2615 burned patients.

Two thousand six hundred and fifteen burned patients are analysed according to mortality rate and the results are compared with other prognostic indices. Our statistical data are similar to those reported by Feller et al. (1976), but differ from those expected by Roi et al. (1983) and Bull (1971). It is suggested that other burns centres should produce their statistical figures in the same way, thereby producing a wider statistical experience and a more accurate prognostic index. The improvement in the survival rate in our centre in the past 5 years is also discussed.

Age Factors↗