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Biomedical subjects

V Ninane

Publications and source records attributed to V Ninane.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Current topics in pulmonary oncology].

Thoracic oncology practice is changing with the end of the century. New diagnostic tools like photodetection allow to diagnose at a white light undetectable level. Preneoplastic lesions or very early cancers that can be locally treated by photochemotherapy, cryotherapy or brachytherapy. The natural history of lung cancer will also be better known. Concerning advanced disease, cisplatin chemotherapy improves survival of patients with stage III non-small cell lung cancer in combination with surgery or chest irradiation and of those with stage IV in comparison with best supportive care alone. New approaches in small cell lung cancer seem promising like accelerated chemotherapy, early chest radiotherapy and maintenance treatment. Moreover, a series of new active cytotoxic agents has been recently identified. The complexity of these modalities makes more and more necessary a integrated pluridisciplinary approach of the lung cancer patient.

Bronchial Neoplasms↗
PubMed1997

[Diagnosis and treatment of early-stage bronchial cancer: current status].

Lung cancer is the cancer with the largest mortality in Belgium. Nowadays, the most potent risk factor for lung cancer, tobacco smoking, is increasing, principally in teenagers. It is therefore necessary to intervene more efficiently in the natural history of the disease. This aim can be achieve by the early detection and the local treatment of small size lung cancer and in situ carcinoma. Interestingly, pulmonary preneoplastic lung lesions have been identified and characterized in the central airways as well as in the peripheral lung parenchyma. These preneoplastic lesions can evolve to invasive cancer or regress after tobacco smoking cessation or chemoprevention treatment. A new autofluorescence based endoscopy technique is described, that allows to detect preneoplastic pulmonary lesions and radio-occult lung cancer. These small sized lesions can be cured with endoscopic local treatment such as photodynamic therapy.

Adolescent↗
PubMed1996

Spinal tuberculosis: a report of five cases and a review.

Spinal tuberculosis (TB) is an uncommon occurrence in developed countries. We present five cases of spinal TB illustrating some of the problems that can be encountered in clinical practice. Delay in diagnosis due to physicians unawareness of TB as a diagnostic possibility in patients with persistent back pain was observed in two patients. A high clinical index of suspicion is, therefore, needed for diagnosis. Tuberculin skin testing was positive in four patients. Computed tomography (CT) has become the examination of choice. It allows precise location of lesions and their extension to paraspinal soft tissue. Furthermore, abscess aspiration and biopsy specimens can be obtained under CT guidance. Magnetic resonance imaging in patients with neurological involvement may provide better information than CT. Definitive diagnosis depending on histological examination, smear and culture of biopsy material, however, may be difficult to obtain. In three patients, diagnosis was based on clinical presentation and response to therapy. Antituberculosis chemotherapy was highly effective in curing all patients. Management of patients should be ensured by experts in antituberculosis chemotherapy, usually chest physicians.

Adult↗
PubMed1995

Endoscopic management of acute respiratory failure related to tracheobronchial malignancies.

Endobronchial treatment has an expanding role in the treatment of tracheobronchial tumors. Most patients are treated in this way for the palliation of dyspnea caused by a tumor located in a major airway. In cases where immediate relief is required, prompt control is better achieved by the neodymium-YAG laser or by stents. These two modalities and their indications and limitations in the endoscopic management of acute respiratory failure related to tracheobronchial malignancies are discussed.

Acute Disease↗
PubMed1995

Effects of increased +Gz on chest wall mechanics in humans.

We studied the effects of head-to-foot acceleration (+Gz) on chest wall mechanics in five normal subjects seated in a human centrifuge. Results were compared with those previously obtained in the same subjects in microgravity during parabolic flights. In all subjects, end-expiratory abdominal pressure (Pga) and volume (Vab) increased with Gz. On average, end-expiratory Pga increased from 7.4 +/- 1.7 cmH2O at + 1 Gz to 14.9 +/- 2.8 cmH2O at + 3 Gz and end-expiratory Vab increased by 0.32 +/- 0.06 liter between + 1 and + 3 Gz. On the other hand, the abdominal contribution to tidal volume (Vab/VT) and abdominal compliance decreased from 34.7 +/- 5.9% and 52 +/- 6 ml/cmH2O at + 1 Gz to 29.3 +/- 5.1% and 26 +/- 4 ml/cmH2O at + 3 Gz, respectively. Changes in end-expiratory Pga were linear between 0 and + 3 Gz, but changes in end-expiratory Vab, Vab/VT, and abdominal compliance were greater in microgravity than in hypergravity. In contrast to weightlessness, which did not alter minute ventilation and tidal changes in Pga and transdiaphragmatic pressure, these variables increased with increasing Gz. These results indicate that, although changes in Gz have a linear effect on abdominal transmural pressure, hypergravity and weightlessness do not have symmetrical effects on chest wall mechanics.

Abdomen↗
PubMed1995

Regulation of breathholding time and sensation after heart-lung transplantation.

To assess whether pulmonary vagal afferents affect the duration of breathholding, the associated respiratory distress and their dependence on lung volume, we studied seven heart-lung transplant (HLT) patients with chronic pulmonary denervation and seven matched control subjects. Voluntary breathholds were performed at 20% and 80% vital capacity (VC) after rebreathing a 7% CO2-93% O2 gas mixture. Time to breakpoint, oxygen saturation, and end-tidal PCO2 were measured. All subjects were questioned on their sensations during breathholding; in addition, quantitative assessment of the sensations was obtained using a visual analog scale (VAS) in the seven control subjects and four HLT subjects. Breathholding time was comparable in both groups at each lung volume but was invariably shorter (p < 0.0005) at 20% VC (mean +/- SD; HLT versus control subjects: 68 +/- 29 versus 79 +/- 29 s) than at 80% VC (corresponding values: 92 +/- 35 versus 103 +/- 30 s). Similar results were obtained after anesthesia of intact tracheal and upper airway receptors in five HLT subjects. Six subjects from each group spontaneously reported air hunger and found it easier to perform breathholding at 80% than at 20% VC. The VAS ratings generally showed a maximum score at breakpoint, which implies that the distress increased more rapidly at low than at high lung volume. We conclude that in the absence of vagal afferent innervation from the lungs: (1) the air hunger form of dyspnea is maintained; (2) the duration of breathholding is not substantially modified; and (3) breathholding time and sensations still vary as a function of lung volume.

Adult↗
PubMed1994

Adverse effect of hyperinflation on parasternal intercostals.

The force-generating ability of the parasternal intercostals is maintained during acute hyperinflation in the dog (Jiang et al. Am. Rev. Respir. Dis. 139: 522-528, 1989). In the present studies, we assessed whether the ability of these muscles to expand the rib cage and inflate the lungs is really maintained. We thus measured the electromyogram and the changes in length of these muscles, the axial motion of the sternum and the ribs, and the changes in pleural pressure and tidal volume in anesthetized vagotomized phrenicotomized dogs during selective parasternal stimulation and during spontaneous breathing at different lung volumes corresponding to 0, 5, 10, and 15 cmH2O positive airway pressure. Compared with functional residual capacity, parasternal stimulation at 15 cmH2O positive airway pressure caused a mild decrease in muscle shortening, a large reduction in cranial rib motion, and a large reduction in pleural pressure fall. The caudal displacement of the sternum, however, was increased. Similar alterations in rib and sternal motions and in muscle shortening were seen during spontaneous breathing; tidal volume was markedly reduced as well. These observations thus indicate that hyperinflation affects the action of the parasternal intercostals on the rib cage; their rib-elevating action is decreased, whereas their action on the sternum is increased. As a result, their ability to inflate the lung is reduced. Thus, the inflationary actions of both the diaphragm and parasternal intercostals are reduced by hyperinflation.

Animals↗
PubMed1993

Intrinsic PEEP in patients with chronic obstructive pulmonary disease. Role of expiratory muscles.

Many patients with severe chronic obstructive pulmonary disease (COPD) contract the transversus abdominis (TA) muscle during expiration. The mechanical correlates of this contraction, however, are uncertain. In the present study, we have measured airflow, esophageal (Pes), and gastric (Pga) pressures, the anteroposterior (AP) diameter of the abdomen, and the electromyogram of the TA during resting breathing in 25 seated patients with severe COPD (FEV1 = 28 +/- 8% of predicted). Nine patients (Group I: FEV1 = 29 +/- 8% of predicted) in general had no TA activity during breathing, and 16 patients (Group II: FEV1 = 27 +/- 8% of predicted) had invariable phasic expiratory TA activity. In all patients of Group II, the decrease in abdomen AP diameter during expiration was associated with a gradual fall in Pga. In contrast, in 13 patients of Group II, the expiratory decrease in abdomen AP diameter was associated with a rise in Pga; this rise in Pga averaged 2.8 +/- 2.2 cm H2O. Furthermore, most patients had positive alveolar pressure at end-expiration, as shown by the time lag between the fall in Pes at the beginning of the inspiratory effort and the onset of inspiratory flow. However, whereas end-expiratory alveolar pressure averaged 2.4 +/- 2.2 cm H2O in Group II, it was only 0.8 +/- 0.6 cm H2O in Group I (p < 0.05). For the patient group as a whole, there was a close relationship between the rise in Pga during expiration and end-expiratory alveolar pressure (r = 0.87; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1993

Respiratory dysfunction in congestive heart failure: correction after heart transplantation.

Severe chronic congestive heart failure (CCHF) is known to induce a restrictive ventilatory defect, with a small decrease in lung transfer factor for carbon monoxide (TLCO). The aim of the present work was to assess the reversibility of this dysfunction. We studied a group of 47 patients with CCHF, before and one year after heart transplantation. The measurements included static and dynamic lung volumes, TLCO and cardiac function. On initial evaluation, vital capacity (VC), total lung capacity (TLC) and TLCO were reduced to 76, 79 and 64% of the predicted value (% pred), respectively. Forced expiratory volume in one second (FEV1) was decreased to 69% pred, with a FEV1/VC ratio below 0.70 in 13 out of 47 patients. One year after transplantation, cardiac function had markedly improved, as shown by a normalized left ventricular ejection fraction (from 18% preoperatively to 59% postoperatively), and mean pulmonary wedge pressure (from 26 to 12 mmHg). At this time, VC (94% pred) and TLC (98% pred) were within the normal range, whereas TLCO remained low (67% pred). The FEV1/VC ratio did not change, even in the subgroup with an initial low value. Smoking habits did contribute to the low TLCO and FEV1/VC ratio. In conclusion, respiratory dysfunction induced by CCHF is reversible, with the exception of the reduction in TLCO, which probably reflects permanent changes in the lung vasculature. CCHF does not induce an obstructive ventilatory pattern.

Female↗
PubMed1992

Rib cage shape and motion in microgravity.

We studied the effect of microgravity (0 Gz) on the anteroposterior diameters of the upper (URC-AP) and lower (LRC-AP) rib cage, the transverse diameter of the lower rib cage (LRC-TR), and the xiphipubic distance and on the electromyographic (EMG) activity of the scalene and parasternal intercostal muscles in five normal subjects breathing quietly in the seated posture. Gastric pressure was also recorded in four subjects. At 0 Gz, end-expiratory LRC-AP and xiphipubic distance increased but LRC-TR invariably decreased, as did end-expiratory gastric pressure. No consistent effect was observed on tidal LRC-TR and xiphipubic displacements, but tidal changes in URC-AP and LRC-AP were reduced. Although scalene and parasternal phasic inspiratory EMG activity tended to decrease at 0 Gz, both muscle groups demonstrated an increase in tonic activity. We conclude that during brief periods of weightlessness 1) the rib cage at end expiration is displaced in the cranial direction and adopts a more circular shape, 2) the tidal expansion of the ventral rib cage is reduced, particularly in its upper portion, and 3) the scalenes and parasternal intercostals generally show a decrease in phasic inspiratory EMG activity and an increase in tonic activity.

Electromyography↗
PubMed1992

Abdominal muscle use during breathing in patients with chronic airflow obstruction.

To assess the pattern of abdominal muscle contraction in stable patients with chronic obstructive pulmonary disease (COPD), we studied electromyograms of the rectus abdominis, external oblique, and transversus abdominis muscles in 40 patients with variable degrees of chronic airflow obstruction (FEV1 between 17 and 82% of predicted); 12 control subjects with normal pulmonary function tests were studied for comparison. The subjects were studied during resting breathing in the supine posture, and the electromyograms were recorded with concentric needle electrodes implanted with the aid of a high-resolution ultrasound. The rectus abdominis and external oblique were silent in virtually all patients. In contrast, 17 patients had invariable phasic expiratory activity in the transversus abdominis, and 11 additional patients had intermittent transversus expiratory activity. Expiratory contraction of the transversus was related to the degree of airflow obstruction (p less than 0.005), and when present, it persisted in the seated posture. We conclude that (1) when breathing at rest, many stable patients with severe chronic airflow obstruction contract the abdominal muscles during expiration, and (2) this expiratory contraction is usually confined to the transversus muscle. These observations also indicate that the physiology of dynamic hyperinflation and intrinsic positive end-expiratory pressure (PEEP) in such patients should be reevaluated.

Abdominal Muscles↗
PubMed1992

Tumour-like presentation of pulmonary sarcoidosis.

We report a case of pulmonary sarcoidosis, which initially presented as a left apical infiltrate. The later course mimicked a pulmonary neoplasm, with left upper lobe atelectasis secondary to bronchial stenosis, resulting from both endobronchial sarcoidosis and extrinsic compression by enlarged lymph nodes. Extrinsic pressure from sarcoid nodes on the left main pulmonary artery and recurrent laryngeal nerve, also caused a reduction in pulmonary parenchymal perfusion and left vocal cord paresis.

Diagnosis, Differential↗
PubMed1991

Action of intercostal muscles on the lung in dogs.

The action on the lung of interosseous intercostal muscles located in the third and the seventh interspaces was studied in 15 anesthetized-curarized supine dogs. Changes in pleural pressure, airflow rate, and lung volume produced by maximal stimulation of both intercostal muscle layers were measured at and above functional residual capacity (FRC). In five animals measurements were also obtained during isolated stimulation of the internal layer. At FRC, intercostal stimulation in the upper interspaces had invariably an inspiratory effect on the lung but no effect was detectable in the lower interspaces. Qualitatively similar results were obtained during isolated stimulation of the internal layer. Increasing lung volume reduced the inspiratory action of the upper intercostals and conferred an expiratory action to the lower intercostals. These results indicate the following: 1) when contracting in a single interspace, the external and internal intercostals have a qualitatively similar action on the lung; and 2) this action, however, depends critically on their location along the cephalocaudal axis of the rib cage: in the upper portion of the rib cage, both muscle layers have an inspiratory effect at and above FRC; in the lower portion of the rib cage, they have no respiratory action at FRC and act in the expiratory direction at higher lung volumes.

Animals↗
PubMed1990

Transversus abdominis muscle function in humans.

We used a high-resolution ultrasound to make electrical recordings from the transversus abdominis muscle in humans. The behavior of this muscle was then compared with that of the external oblique and rectus abdominis in six normal subjects in the seated posture. During voluntary efforts such as expiration from functional residual capacity, speaking, expulsive maneuvers, and isovolume "belly-in" maneuvers, the transversus in general contracted together with the external oblique and the rectus abdominis. In contrast, during hyperoxic hypercapnia, all subjects had phasic expiratory activity in the transversus at ventilations between 10 and 18 l/min, well before activity could be recorded from either the external oblique or the rectus abdominis. Similarly, inspiratory elastic loading evoked transversus expiratory activity in all subjects but external oblique activity in only one subject and rectus abdominis activity in only two subjects. We thus conclude that in humans 1) the transversus abdominis is recruited preferentially to the superficial muscle layer of the abdominal wall during breathing and 2) the threshold for abdominal muscle recruitment during expiration is substantially lower than conventionally thought.

Abdominal Muscles↗
PubMed1989

Abdominal muscle use during breathing in unanesthetized dogs.

The pattern of abdominal muscle use during breathing in unanesthetized dogs is unknown. Therefore, we have recorded the electromyograms of the rectus abdominis, external oblique, and transversus abdominis in eight conscious animals breathing quietly in the sitting, standing, and prone postures. During quiet breathing in the sitting posture, all animals invariably had a large amount of phasic expiratory activity in the transversus abdominis. In contrast, only four animals showed some expiratory activity in the external oblique, and only one animal had expiratory activity in the rectus abdominis. A similar pattern was observed when the animals were standing or lying prone, although the amount of expiratory activity was less in this posture. Bilateral cervical vagotomy in four animals did not affect the degree of transversus abdominis expiratory activation or the influence of posture. We conclude that in conscious dogs 1) the abdominal muscles play an important role during breathing and make spontaneous quiet expiration a very active process, 2) the transversus abdominis is the primary respiratory muscle of the abdomen, and 3) unlike in anesthetized animals, extrapulmonary receptors play a major role in promoting abdominal expiratory contraction.

Abdominal Muscles↗
PubMed1989

Mechanism of triangularis sterni shortening during expiration in dogs.

The triangularis sterni in the dog shortens during expiration below its in situ relaxation length (Lr) (J. Appl. Physiol. 61: 539-544, 1986). To assess the mechanism of this expiratory muscle shortening, we have measured the electromyogram and the respiratory changes in length of the canine triangularis sterni in the third and fourth right intercostal space, first before and then after selective denervation. Eleven anesthetized, spontaneously breathing animals were studied in the supine posture; five of them were also studied during postural changes from supine to head-up. Before denervation, the muscle in the supine animals shortened by -12.84 +/- 1.81% Lr. With selective denervation, the amount of expiratory muscle shortening was reduced to only -2.54 +/- 0.71% Lr (P less than 0.001). Similarly, a change from the supine to the head-up posture before denervation promoted an increase in expiratory muscle shortening from -13.58 +/- 3.62 to -21.17 +/- 4.04% Lr (P less than 0.005), but the denervation abolished this increase. Denervating the triangularis sterni, however, did not affect expiratory activation of the internal intercostals. These results demonstrate that the expiratory contraction of the canine triangularis sterni is agonistic in nature, and they suggest that this contraction is responsible for most of the active caudal displacement of the ribs in the upper half of the rib cage.

Animals↗