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We determined the indices of local vibrations (resonance frequency, damping coefficient, stiffness constant, extinction time) and transfer function H(s) . 10(-6) for three somatotypes and three respiratory positions on 88 points of the thorax. The examinees were males (age 21 years). We found the resonance frequencies of 36.86--54.75 cps, damping coefficient (delta) 0.121--0.217. This means the damping is less than critical (delta = 1). We applied shocks (a force of 2 N) with a reflex hammer on 88 points of the thorax. The force diminished from the exciting place (say ictus) to the recording place (accelerometer on the sternum) from 2 to 0.2 N. The athletic type has the highest resonance frequency and stiffness constant; the leptosomic type has the highest damping; the longest extinction time belongs to the pyknic type. The pyknic type has also the highest value of the transfer function. The respiratory position (quiet respiration, Valsalva and Müller experiment) influences the values of the indices of local vibrations and of the transfer function. The influence is evident especially on the intercostal points: the transfer of the oscillations is alleviated at a higher stiffness of the thorax (Valsalva; the value of H(S) . 10(-6) rises from 7.00 to 9.39 sec2), it deteriorates at a small stiffness of the thorax (in Müller's experiment falls to 2.78 sec2). With the fall in the intrathoracic pressure the damping in the intercostal points decreases. On the basis of experiments the conclusion was made that a short testing of the thorax of an examinee will give the dynamic characteristics of the thorax (indices of local vibrations and transfer functions) of the individual. This procedure will alleviate the quantitative use of noninvasive mechanical methods in the assessment of the cardiovascular function.
The component model modal synthesis technique has been successfully adapted to the finite element structural dynamic model of the human thorax for chest impact response and injury studies. The complete thorax was modeled as an assembly of a thorax module with viscera subsystems. The module was further subdivided into rib components. Major model development was conducted at the component level to provide cost saving and modeling flexibility. The results show that the thorax can be successfully treated as a linear system. A two-step procedure was developed to obtain viscera response. The analysis results of THORAX III, a first cut thorax model, were favorably compared with Kroell-Nahum cadaver experiments. The sensitivity of the chest response due to variation in input pulse shape and peak force were analyzed. The pulse shape can affect the force-deflection relationships while peak force affects the peak response. Further sensitivity studies and experiments are proposed.
The free and bound forms of alpha,alpha-trehalase (EC 3.2.1.28) of the honey bee thorax were separated and the bound enzyme was solubilized by raising the pH to 8.0 for 10 h. Both enzymes were purified. They were homogeneous as determined by several electrophoretic criteria. It was found that the two enzymes had very similar Km's (each about 0.89 mM), Vm's (53.2 and 54.3 U/mg for free and solubilized, respectively), inhibition characteristics, specificities (both only hydrolyzed alpha,alpha-trehalose), pH maxima (each had maxima at about 3.5 and 6.5), molecular weights (65,000), isoelectric points (5.1), reactivities to sulfhydryl reagents, electrophoretic mobilities, activation energies (about 12.8 kcal/mol), and similar stabilities to heat, pH, and urea. Some significant differences between the two enzymes were, however, found: the solubilized alpha,alpha-trehalase floated at 70% saturation of ammonium sulfate while the free alpha,alpha-trehalase did not; the solubilized alpha,alpha-trehalase did not dissociate into subunits as readily as did the free one; and the solubilized alpha,alpha-trehalase was found to bind more readily to a hydrophobic grouping than the free enzyme. In addition to these comparisons, three new findings relating to thorax alpha,alpha-trehalases are reported. (1) Thorax alpha,alpha-trehalases are strongly inhibited by beta-glucosides (Ki values of about 8 x 10(-4) M); (2) under certain conditions thorax alpha,alpha-trehalases from honey bees dissociated into subunits of one-half the normal molecular weight; (3) honey bee thorax alpha,alpha-trehalases have unusual biphasic pH activity profiles.
1. The narrow passage within the petiole between thorax and abdomen is anatomically constructed so that counter-current exchange should retain heat in the thorax despite blood flow to and from the cool abdomen. 2. However, the counter-current heat exchanger can be physiologically circumvented. Exogenously heated bumblebees prevented overheating of the thorax by shunting heat into the abdomen. They also regurgitated fluid, which helped to reduce head temperature but had little effect on thoracic temperature. 3. Temperature increases in the ventrum of the abdomen occurred in steps exactly coinciding with the beats of the ventral diaphragm, and with the abdominal 'ventilatory' pumping movements when these were present. The ability to prevent overheating of the thorax by transport of heat to the abdomen was abolished when the heart was made inoprative. 4. At low thoracic temperatures the ventral diaphragm beat at a wide range or rates and with varying interbeat intervals, while the heart beat at a high frequency relative to the ventral diaphragm, but at a very low amplitude. However, when thoracic temperature exceeded 43 degrees C the amplitudes of both were high, and the interbeat intervals as well as the beating frequencies of the two pulsatile organs became identical in any one bee. Furthermore, heated bees engaged in vigorous abdominal pumping at the same frequency as that of their heart and ventral diaphragm pulsations. 5. The results indicate that the anatomical counter-current heat exchanger is reduced or eliminated during heat stress by 'chopping' the blood flow into pulses, and the blood pulses are shunted through the petiole alternately by way of a switch mechanism.
Blunt traumata cause injury to the thorax and intrathoracic organs by deforming the chest wall and the enclosed structures. Neither examination of the dead person and re-enactment of the accident nor experimental studies on the living or dead person can fully elucidate the course of events. A more satisfactory approach is to use biomechanic models to simulate the structure of the thorax and the type of deformation it undergoes when subjected to various traumata. Such an elasto-static analysis presupposes knowledge of (1) the global geometry of the thorax; (2) the cross sectional geometry of the individual components; (3) the mechanical properties of the material; (4) the force of the impact; (5) concomitant conditions. The results obtained with the models are reviewed. They make it possible to predict the deformation of the thorax in response to the force of the impact, the location and type of fracture of the ribs and the deformation of the intrathoracic organs.
The types of injuries to 313 automobile accident victims, especially thorax injuries, are compared. Independent of seat belt use (42%), there was in general a higher degree of injury. Those wearing seat belts had a markedly less severe AISm (median degree of injury of body region) and less severe thorax injury. Severe thorax injury was first found at speeds greater than 24 km/h above average. Severer thorax injury is to be expected with defective seat belts (AISm = 1.25) than with properly functioning belts (AISm = 0.32).
Differential and sucrose gradient centrifugation of honey bee thoraces, disrupted by gentle methods and using mannitol-triethanolamine-EDTA buffer at pH 6.5, showed that in the honey bee thorax 92-94.8% of the trehalase was mitochondrial. Since only 92-95% of the cytochrome c oxidase, a known mitochondrial enzyme, was found in the mitochondrial fraction by these methods, it was concluded that honey bee trehalase is totally mitochondrial. Significant amounts of 'microsomal' or 'soluble' trehalase were formed only by harsh methods of thorax disruption and similar 'microsomal' or 'soluble' trehalases were also formed by harsh treatment of purified whole mitochondria. They thus seem to be artifacts of the isolation procedure. Studies (using marker enzymes) with purified intact mitochondria which were dispersed by various chemical, enzymatic, and physical methods showed that the trehalase in the mitochondria was membrane bound and that it was bound to either the outside of the inner membrane or to one of the sides of the outer membrane.
Computed tomography (CT) provides a valuable new perspective in assessing abnormalities of the thorax. In the patient with a mediastinal mass or widening detected by plain chest radiography, a definitive diagnosis is sometimes possible which would not be obtainable by conventional noninvasive radiological techniques. In certain clinical situations, CT is a highly sensitive modality for examining the lungs. The proved and potential clinical uses of CT in solving diagnostic problems of the thorax are discussed.
Respiratory changes in pleural pressure were recorded simultaneously from the left and right pleural spaces in 6 anesthetized closed-chest dogs in the supine, prone, left lateral and right lateral positions. Saline-filled radiopaque catheters connected to strain-gauge manometers were inserted percutaneously in the left and right pleural spaces by an air tight technique and their tips were placed in the mid-thoracic plane. The esophageal pressure was also recorded with the saline-filled system. The value of respiratory pressure amplitude (deltap, the difference between end-expiratory and minimal inspiratory pressures) in the pleural spaces was significantly greater in the left thorax than in the right in the supine, prone and right lateral positions. In 4 body positions, deltap in pleural pressure was significantly greater than in esophageal pressure. It is concluded that respiratory variations in pleural pressure of the left and right thorax are not the same and that postural change does not produce significant regional difference of the respiratory variations.
Two variants of autopsy of cadavers without cutting of the thorax and dissection of the ribs are described. The method is principally based on the transversal cutting of the abdominal wall alongside both hypochondria, severing of the diaphragm and exposure of a complex of organs (after preliminary removal of the intestine and spleen). In the first variant of autopsy, the upper part of the complex is crossed in the thorax at the level of the upper aperture of the thoracic cavity, leaving the organs of the neck without autopsy. In the second variant, no such crossing is done and the complex is removed together with the organs of the neck and the tongue (that is, the autopsy is complete). To separate the latter, an additional transversal supraclavicular cut about 10 cm in length is made. The advantages of these variants lie in the cosmetic effect.
Thirteen of 324 patients with malignant melanoma followed during a 24 month period experienced dissemination. The thorax was the initial site for relapse in 12, all of whom were asymptomatic. Ten gave no evidence of extrathoracic disease. Retrospective analysis of previous x-rays originally interpreted as negative revealed metastases in 33%. Life table analysis demonstrated a significantly longer survival for the subset with isolated intrathoracic metastases treated surgically than for their counterparts with metastases no longer amenable to surgery and treated by other modalities. We conclude that the thorax is the site of predilection for initial systemic relapse in malignant melanoma, that detection of early, surgically resectable metastases correlates with longer patient survival, and that routine chest roentgenography is inadequate in reliably uncovering such early disease. These data suggest the potential value of more vigorous radiographic surveillance (with either computed tomography or conventional full lung tomography) in patients at high risk for relapse.
Radiographs of the thorax were evaluated in 240 patients during the acute phase following a myocardial infarct. Following the acute infarct, 53% of the patients showed some cardiac enlargement, in a quarter this was marked. Congestive lung changes were found in 53% of patient following the infarct, interstitial pulmonary oedema in 22% and intra alveolar oedema in 9%. Patients with marked cardiac enlargement and those with congestive lung changes showed a bad prognosis, particularly if the congestion did not regress rapidly. Even advanced pulmonary congestion and interstitial oedema may be missed by clinical examination. Radiography of the thorax following acute myocardial infarction is of value in treatment and prognosis.
The potential value of indium-labelled bleomycin as a diagnostic scanning agent has been investigated in patients with a variety of malignant neoplasms involving the thorax, abdomen or pelvis. Sixty-five patients were scanned on 72 occasions, the optimum time to perform the examination being 72 hours after the intravenous injection of 2 mCi 111-In chelated to 2 mg bleomycin. Tumour uptake was visualized in 53 out of 62 scans in which tumour was present, but the extent of tumour was underestimated in seven cases, and over-estimated in five others. The latter were mostly due to uptake in infective lesions. These results indicate that the situations in which indium bleomycin is most likely to provide clinically relevant information are the distinction between recurrent tumour and post-radiotherapy changes in the thorax and pelvis, the diagnosis of recurrent carcinoma within the pelvis, and the distinction between bony metastases from carcinoma of the prostate and Paget's disease. Further clinical trials are necessary to assess these situations.
The radiographic signs previously described for fatty tumors of the thorax although helpful are nonspecific. In the past, the diagnosis of benign fatty tumors of the chest in asymptomatic patients required surgical intervention. This report illustrates the gamut of fat-containing tumors of the thorax encountered over a recent 1 year period. CT proved to be helpful in the diagnosis and management on these cases. When the CT numbers of the fatty lesion was around -55 EMI units, intervention was felt to be unnecessary. However, when the CT number of the mass ranged from --10 to--20 EMI units, intervention was felt to be necessary since a malignancy could not be excluded on the basis of the CT findings alone.
Every year 8,000 persons involved in road accidents die of irreversible respiratory insufficiency caused by chest injuries. Fractures of the ribs extendig over a number of ribs are present in 70% of the cases and in 15% of them they are accompanied by instability of the thorax and "paradoxical" respiration. Treatment of the instability by "internal pneumatic splinting" (Avery) and by surgical measures is reviewed. Indications for the latter are: (1) open fractures of the chest wall; (2) instability of the thorax combined with intrathoracic injuries; (3) instability of the chest wall with severe therapy-resistant respiratory insufficiency. In a series of animal experiments unilateral instability of the chest wall was induced by multiple rib fractures. By measuring oscillatory resistance before and after stabilization of chest wall the effects of the latter on the impaired lung function could be demonstrated. The results of the experiments indicate that with this type of surgical treatment mortality from combined thoracic injuries with paradoxical breathing can be reduced.
Anteroposterior diameters of the rib cage and abdomen and esophageal and gastric pressures were measured in normal subjects in upright and supine body positions during respiratory maneuvers and utterance tasks. Data were charted in relative motion diagrams and various motion-pressure diagrams which enabled graphic solution for muscular pressures exerted by the chest wall and individually by the thorax, rib cage, diaphragm, and abdomen during utterances. Behaviors of the chest wall and its parts were found to depend upon lung volume, utterance loudness, body position, and utterance task. For utterances encompassing most of the vital capacity, chest wall effort was at first net inspiratory and later net expiratory. The former was governed predominately by the rib cage and the abdomen in the upright body position and by the diaphragm in the supine position. For conversational speech, chest wall effort was continuously expiratory, control being vested in the rib cage and the abdomen in the upright body position and typically in the rib cage alone in the supine position. Mechanisms operating during the utterances are discussed, particularly those involved with conversational speech production. We conclude that the abdomen occupies an especially important role in running conversational speech in that it mechanically tunes the diaphragm to increase the latter's inspiratory efficiency and thus enables man to minimally interrupt his ongoing speech for needed inspiratory pauses. We also discuss the relevance of our findings to clinical endeavors.