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Biomedical subjects

V Ninane

Publications and source records attributed to V Ninane.

At least 91 records · Page 5Linked to original sources
PubMed1989

Mechanism of rib cage inspiratory muscle recruitment in diaphragmatic paralysis.

Paralysis of the diaphragm promotes an increase in the activation of the rib cage inspiratory muscles, and previous studies have suggested that this compensation is primarily due to vagal mechanisms (6). To test this hypothesis, we have assessed the effect of diaphragmatic paralysis on the electrical response of 19 parasternal intercostal muscles in eight anesthetized, vagotomized, spontaneously breathing dogs in the supine posture. Complete diaphragmatic paralysis was induced by section of the C5, C6, and C7 phrenic nerve roots in the neck. With the animals breathing room air, diaphragmatic paralysis resulted in a mean 94% increase in the peak height of integrated parasternal activity (p less than 0.001) associated with a 14 mm Hg decrease in arterial PO2 (p less than 0.05) and an 8 mm Hg increase in arterial PCO2 (p less than 0.001). The augmented parasternal activity was unrelated to the duration of inspiration and persisted when the animals were given a hyperoxic gas mixture. Thus the rib cage inspiratory muscles still compensate for diaphragmatic paralysis in the absence of vagal signals and of hypoxemia. This compensation probably results from the considerably augmented CO2 load placed on the extradiaphragmatic muscles.

Animals↗
PubMed1988

Vasoconstrictive effect of portal blood in isolated dog kidney.

Humoral vasoactive substances coming from portal blood have been considered as a possible cause of renal dysfunction in cirrhotic patients. We have thus investigated the effect of perfusion of portal blood from anesthetized dogs on the isolated kidney functions. Both kidneys of a dog were simultaneously perfused on 2 Nizet's pump oxygenators, one kidney serving as control for the other. Renal blood flow was decreased in kidneys perfused with portal blood, as compared to the paired control kidneys perfused with sus-hepatic blood (group A experiments). Addition of polymyxin B to the portal blood restored the renal blood flow to the control level (group B experiments). No significant changes appeared between experimental and control kidneys for glomerular filtration rate, urine output, sodium and water excretion, renin activity, angiotensin II levels, plasmatic PGE2 levels, in group A as well as in group B. We conclude that portal blood of dogs contains vasoactive substances reducing renal blood flow; their action is mediated neither by the renin-angiotensin system nor by changes in renal PGE2 production. The complete abolition of this effect by Polymyxin suggests that these substances may be endotoxins.

Animals↗
PubMed1988

Triangularis sterni muscle use during eupnea in humans: effect of posture.

The electromyograms of the triangularis sterni (transversus thoracis), of the abdominal external oblique, and of the deeper abdominal muscle layer (internal oblique or transversus abdominis) were recorded with concentric needle electrodes in twenty normal naive subjects breathing quietly in the supine and the standing posture. The triangularis sterni and abdominal muscles were usually silent in the supine posture. In contrast, all subjects in the standing posture showed activity in the abdominal muscles, and sixteen subjects also had activity in the triangularis sterni. The abdominal muscle activity was principally tonic, unrelated to the phases of the breathing cycle, whereas in fifteen subjects the triangularis sterni activity was confined to expiration. Expiratory activation of the triangularis sterni was more frequently observed in the older than in the younger subjects of the study. These observations indicate that unlike in the supine posture, most normal subjects when breathing at rest in the standing posture recruit both the triangularis sterni and the abdominal muscles. This recruitment may compensate for the adverse effects of the standing posture on the diaphragm and rib cage inspiratory muscles.

Adolescent↗
PubMed1988

Changes in abdominal muscle length during breathing in supine dogs.

To assess the mechanical function of the abdominal muscles during eupnea in the dog, we have measured the electrical activity and the respiratory changes in length of the rectus abdominis, external oblique, and transversus abdominis muscles in eight supine, lightly anesthetized, spontaneously breathing animals. Seven animals had phasic expiratory electromyographic (EMG) activity in the transversus and showed expiratory shortening of the muscle below its in situ relaxation length (Lr). In contrast, only three animals had expiratory EMG activity and expiratory shortening of the external oblique, and no animal had expiratory EMG activity in the rectus. Seven animals, however, showed shortening of the rectus muscle during expiration. The amount of transversus expiratory shortening in the eight animals averaged (mean +/- SE) - 7.61 +/- 1.72% Lr and was significantly larger (P less than 0.005) than the amount of external oblique (-0.11 +/- 0.10% Lr) or rectus (-0.90 +/- 0.39% Lr) expiratory shortening. Hyperoxic hypercapnia amplified these differences. These data thus indicate that in supine anesthetized dogs (1) the transversus is, in real mechanical terms, the primary abdominal muscle of expiration; and (2) the abdominal compartment of the chest wall during eupnea moves both below and above its neutral position, and not exclusively above it.

Abdominal Muscles↗
PubMed1988

Mechanics of the parasternal intercostals during occluded breaths in dogs.

The electrical activity and the respiratory changes in length of the third parasternal intercostal muscle were measured during single-breath airway occlusion in 12 anesthetized, spontaneously breathing dogs in the supine posture. During occluded breaths in the intact animal, the parasternal intercostal was electrically active and shortened while pleural pressure fell. In contrast, after section of the third intercostal nerve at the chondrocostal junction and abolition of parasternal electrical activity, the muscle always lengthened. This inspiratory muscle lengthening must be related to the fall in pleural pressure; it was, however, approximately 50% less than the amount of muscle lengthening produced, for the same fall in pleural pressure, by isolated stimulation of the phrenic nerves. These results indicate that 1) the parasternal inspiratory shortening that occurs during occluded breaths in the dog results primarily from the muscle inspiratory contraction per se, and 2) other muscles of the rib cage, however, contribute to this parasternal shortening by acting on the ribs or the sternum. The present studies also demonstrate the important fact that the parasternal inspiratory contraction in the dog is really agonistic in nature.

Animals↗
PubMed1988

Mechanics of parasternals and triangularis sterni in upright vs. supine dogs.

The parasternal intercostals in supine dogs are activated and shorten during inspiration, whereas the triangularis terni is activated and shortens during expiration (J. Appl. Physiol. 61: 539-544, 1986). How the two muscles respond to posture, however, is not known. Thirteen vagotomized, phrenicotomized, spontaneously breathing animals were thus studied during multiple postural changes from supine to 80 degrees head up and 20 degrees head down. Head-up tilting elicited a gradual increase in the electrical activation of both the triangularis sterni and the parasternals. Recruitment of the triangularis sterni promoted an increase in the amount of expiratory muscle shortening, but recruitment of the parasternals was invariably associated with a considerable reduction in the amount of inspiratory muscle shortening. This reduction was abolished after sectioning of the abdominal wall. We conclude that 1) the contribution of the canine triangularis sterni to rib movement increases with the assumption of the upright posture, whereas the contribution of the parasternals decreases and 2) this decrease results primarily from the load imposed on the rib cage by gravitational forces. Thus assuming the upright posture adversely affects the rib cage inspiratory muscles as well as the diaphragm.

Abdominal Muscles↗
PubMed1987

Abdominal muscle use during breathing in the anesthetized dog.

The electromyograms of the rectus abdominis, external oblique, and transversus abdominis muscles were recorded in eight lightly anesthetized, spontaneously breathing dogs. During quiet breathing in the supine posture seven animals invariably had a phasic expiratory activity in the transversus, whereas only two animals had invariable expiratory activity in the external oblique. An intermittent expiratory activity in the rectus was recorded in only one animal. The degree of activation, expressed as a percentage of the activity detected during breathing with 25 cm H2O positive end-expiratory pressure (PEEP), was also significantly greater (P less than 0.05) for the transversus (mean +/- SEM: 29.4 +/- 8.6%) than the external oblique (5.5 +/- 2.3%). Head up tilting and progressive hypercapnia elicited substantial increases in transversus and external oblique expiratory activity in all animals, whereas head down tilting caused marked decreases in expiratory activity. In each posture and at any given end-tidal CO2, however, the amount of transversus activity was larger than the amount of external oblique activity. The rectus was usually silent in all the conditions. Bilateral cervical vagotomy suppressed external oblique activity in most supine animals, and the muscle was no longer recruited by PEEP, head up tilting, or hypercapnia. In contrast, there was residual transversus expiratory activity in all supine animals (11.1 +/- 3.1%), as well as some expiratory recruitment during PEEP, head up tilting, and hypercapnia. These results indicate that: (1) the transversus is the primary abdominal muscle of expiration in the anesthetized dog; and (2) its behavior resembles that of the triangularis sterni, although it is more dependent on vagal afferent pathways. The present findings also strengthen the important fact that spontaneous quiet expiration in the dog is an active rather than passive process.

Abdominal Muscles↗
PubMed1987

Effect of posture on expiratory muscle use during breathing in the dog.

The electromyographic (EMG) activity of the triangularis sterni and abdominal external oblique muscles was studied in 10 lightly anesthetized, spontaneously breathing dogs during postural changes from supine to head up and head down. The triangularis sterni was active during expiration in all animals when breathing in supine posture, whereas the external oblique was active in only 6 animals. A change from the supine to head up posture elicited a marked increase in triangularis sterni and external oblique expiratory EMG activity in all animals. A change from the supine to head down posture conversely caused the triangularis sterni expiratory activity to decrease and the external oblique expiratory activity, when present in supine posture, to be markedly reduced or abolished. The external oblique was generally silent after bilateral cervical vagotomy and no longer responded to posture. In contrast, bilateral vagotomy had no clear-cut effect on either the active use of the triangularis sterni in supine posture or on the muscle response to posture. These results indicate that: the active nature of spontaneous quiet expiration in the dog is not specific to the supine posture; the adoption of the head up posture actually is associated with considerable phasic expiratory recruitment of the triangularis sterni and abdominal muscles, so that moving the chest wall during breathing is proportionately more an expiratory act and less an inspiratory act than in supine posture; and in contrast to the abdominal muscles, the postural changes in triangularis sterni use during breathing are largely independent of vagal inputs.

Animals↗
PubMed1987

Triangularis sterni muscle use in supine humans.

The electrical activity of the triangularis sterni (transversus thoracis) muscle was studied in supine humans during resting breathing and a variety of respiratory and nonrespiratory maneuvers known to bring the abdominal muscles into action. Twelve normal subjects, of whom seven were uninformed and untrained, were investigated. The electromyogram of the triangularis sterni was recorded using a concentric needle electrode, and it was compared with the electromyograms of the abdominal (external oblique and rectus abdominis) muscles. The triangularis sterni was usually silent during resting breathing. In contrast, the muscle was invariably activated during expiration from functional residual capacity, expulsive maneuvers, "belly-in" isovolume maneuvers, static head flexion and trunk rotation, and spontaneous events such as speech, coughing, and laughter. When three trained subjects expired voluntarily with considerable recruitment of the triangularis sterni and no abdominal muscle activity, rib cage volume decreased and abdominal volume increased. These results indicate that unlike in the dog, spontaneous quiet expiration in supine humans is essentially a passive process; the human triangularis sterni, however, is a primary muscle of expiration; and its neural activation is largely coupled with that of the abdominals. The triangularis sterni probably contributes to the deflation of the rib cage during active expiration.

Adult↗
PubMed1986

Triangularis sterni: a primary muscle of breathing in the dog.

The isolated action, pattern of neural activation, and mechanical contribution to eupnea of the triangularis sterni (transversus thoracis) muscle were studied in supine anesthetized dogs. Linear displacement transducers were used to measure the axial displacements of the ribs and sternum. Tetanic stimulation of the triangularis sterni in the apneic animal caused a marked caudal displacement of the ribs, a moderate cranial displacement of the sternum, and a decrease in lung volume. During quiet breathing, there was invariably a rhythmic activation of the muscle in phase with expiration that was independent of the presence or absence of activity in the abdominal and internal interosseous intercostal muscles. This phasic expiratory activity in the triangularis sterni was of large amplitude and caused the ribs to be more caudal and the sternum to be more cranial during the spontaneous expiratory pause than during relaxation. Additional studies on awake animals showed that rhythmic activation of the triangularis sterni occurs in all body positions and is not caused by anesthesia. These findings indicate that expiration in the dog is not a passive process and that the end-expiratory volume of the rib cage is not determined by an equilibrium of static forces alone. Rather, it is actively determined and maintained below its relaxation volume by contraction of the triangularis sterni throughout expiration. The use of this muscle is likely to facilitate inspiration by increasing the length of the parasternal intercostals and taking on a portion of their work.

Animals↗
PubMed1986

Respiratory function of intercostal muscles in supine dog: an electromyographic study.

It is traditionally considered that the difference in orientation of the muscle fibers makes the external intercostals elevate the ribs and the internal interosseous intercostals lower the ribs during breathing. This traditional view, however, has recently been challenged by the observation that the external and internal interosseous intercostals, when contracting alone in a single interspace, have a similar effect on the ribs into which they insert. This view has also been challenged by the observation that the external and internal intercostals in a given interspace often change their length in the same direction during breathing. In an attempt to clarify the respiratory function of these muscles, we studied eight supine lightly anesthetized dogs during quiet breathing and during static inspiratory efforts. In each animal electromyographic (EMG) recordings from the external and internal interosseous intercostals were obtained in all interspaces from the second to the eighth, and selective denervations were systematically performed to ensure with complete certainty the origin of the recorded EMG activities. The external intercostals were only activated in phase with inspiration, whereas the internal interosseous intercostals were only activated in phase with expiration. These phasic EMG activities, however, were generally small in magnitude, and the muscles were often silent. Indeed, activation of the externals was always confined to the upper portion of the rib cage, whereas activation of the internals was limited to the lower portion of the rib cage. Internal intercostal activation always occurred sequentially along a caudocephalic gradient. These observations are thus compatible with the traditional view of intercostal muscle action.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Coupling between triangularis sterni and parasternals during breathing in dogs.

The purpose of the present studies was to assess the functional coupling between the parasternal intercostals and the triangularis sterni (transversus thoracis) muscles during resting breathing, and we measured the electrical activity and the respiratory changes in length of these two muscles in 13 supine anesthetized dogs. The changes in muscle length were defined relative to their respective in situ relaxation length (Lr). During inspiration, the parasternal intercostals were active and shortened below Lr, causing the triangularis sterni to be passively stretched above Lr. Shortly after the cessation of parasternal contraction, the triangularis sterni became active and shortened below Lr, and in nine animals this active shortening was associated with a forcible distension of the parasternal intercostals above Lr. Deactivation of the triangularis sterni at end expiration caused both muscles to return to their respective Lr. This pattern was essentially unchanged after supplemental anesthesia and bilateral phrenicotomy. We conclude that in dogs breathing quietly the length of the rib cage muscles during the expiratory pause is not passively determined as conventionally thought.

Anesthesia↗
PubMed1985

Rib cage mechanics in simulated diaphragmatic paralysis.

To determine the action of the parasternal intercostals on the human rib cage, we studied the pattern of rib cage motion in relation to the pattern of respiratory muscle contraction in 4 normal subjects during attempts to perform tidal volume breathing with the parasternal intercostals alone. The dimensions of the chest wall, including the anteroposterior (AP) diameters of the lower rib cage and the abdomen, the transverse diameter of the lower rib cage, and the xiphipubic distance, were measured with linearized magnetometers. The electromyogram (EMG) of the diaphragm was obtained with an esophageal lead, while the EMGs of the intercostal, neck, and abdominal muscles were recorded using concentric needle electrodes. Minimizing diaphragmatic use during inspiration (transdiaphragmatic pressure = 0.08 to 1.54 cm H2O) was accompanied by a recruitment of the parasternals that was substantially greater than that of the scalenes; in 2 of the subjects, the activation of the scalenes at the beginning of inspiration was even delayed relative to the parasternals. The lateral intercostals showed variable changes during the maneuver, but the sternocleidomastoids, pectoralis major, rectus abdominis, and abdominal external oblique muscles were always silent. This pattern of EMG activity was associated with profound deformations of the rib cage. In all 4 subjects, the rib cage expanded considerably more along its transverse than its AP dimension relative to its relaxed configuration, and in 3 subjects, the xiphi-pubic distance decreased rather than increased in early inspiration.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1984

What is emergency? Analysis of a population presenting to an emergency room.

The population presenting at emergency rooms is increasing in Belgium. What is emergency in 1983 and why do people come? From a study of the emergency room population in a relatively new university hospital it emerges that more than 30% of those patients are in critical conditions or require in hospital treatment and about 50% are in acute discomfort. Our results confirm the impression that inappropriate use of emergency rooms is more an impression than a real problem. For socio-economic and cultural reasons, people go to emergency rooms when they need or think they should have medical help. Some emergency rooms are well able to cope with this situation. Others, less well-equipped in staff and facilities are dangerous and should be improved or closed. Unfortunately education and training programs for emergency physicians are still unknown in many parts of the French-speaking Belgium.

Adult↗
PubMedDate not supplied

Expression of p53 in preneoplastic and early neoplastic bronchial lesions.

p53 alteration has been reported to be an early event in bronchial carcinogenesis. Our study purpose was to determine the rate of p53 expression in the various preneoplastic and early neoplastic bronchial lesions obtained by biopsy during fluorescence bronchoscopy and to analyse its association with patients characteristics. Various stages of preneoplastic lesions as well as radio-occult lung cancer were studied in biopsies obtained by fluorescence bronchoscopy. We assessed the expression of p53 by immunohistochemistry using monoclonal antibody clone DO7. The p53 expression was considered as positive if > or = 1% of cells were positive and the level of positivity was expressed in percentage of positive cells. Fourteen patients were included in each category of preneoplastic lesions. At the threshold of 1% of positive cells p53 expression was observed in 28.5% of the patients with a histologically normal epithelium. This number of positive patients increased with the severity of preneoplastic lesions and reached 100% in the mild dysplasia. The mean rates of p53 positive cells for normal epithelium, hyperplasia, metaplasia, mild and severe dysplasia, carcinoma in situ and invasive radio-occult carcinoma were respectively 0.9, 3.4, 9.1, 20.5, 50.2, 34.7 and 42.5%. There was no statistically significant correlation between p53 expression and patient characteristics such as sex, age, smoking habits and indication for fluorescence bronchoscopy. The alteration of p53 expression in patients with high risk of lung cancer was an early event: this abnormality increased with the severity of the lesions, without significant correlation with patient characteristics.

Adult↗
PubMedDate not supplied

Expression of thrombospondin in non-small cell lung cancer.

OBJECTIVE: Initially considered as an inhibitor of angiogenesis, the role of thrombospondin is currently controversial. The primary purpose of our study was to determine the expression of thrombospondin (TSP) in invasive lung tumours. The secondary objectives were to investigate its relationship with other factors related to angiogenesis and to assess their clinicopathological significance. MATERIALS AND METHODS: From January 1993 to September 1998, we collected non-small cell lung cancer (NSCLC) and normal nearby-matched tissues from surgical specimens of 64 patients. Using these specimens, we assessed the expression of TSP by immunohistochemistry with monoclonal antibody to human TSP (clone 11.4). This expression was also correlated with other factors directly or indirectly related to angiogenesis:p53, Ki-67 as proliferation factor and microvessel count determined with anti-CD-31 antibody. RESULTS: The resected tumours (stages I-IIIB) consisted of 30 adenocarcinomas, 24 squamous cell carcinomas, 5 bronchioalveolar carcinomas, 4 adenosquamous carcinomas and 1undifferentiated NSCLC. The mean values of TSP expression in neoplastic and normal related tissues were 63.08% and 86.57 %, respectively. This difference was statistically significant (p = 0.02). There was a higher level of variability of TSP expression between tumours than between normal tissues. The expression of TSP in NSCLC was statistically correlated to the expression of TSP in normal matched tissues (coefficient correLation rate = 0.31, p<0.01). The median expression of p53, Ki-67 and microvessel count in tumours was 45.00%, 38.80% and 8.33%, respectively. The correlations between TSP and the other biological variables and between these latter variables themselves were not statistically significant. No statistically significant difference was observed in survival according to TSP expression. CONCLUSION: TSP appeared to be decreased in NSCLC in comparison with normal matched tissue. The TSP expression was not correlated with the other studied variables and was not associated with a significant difference in survival.

Adult↗