Leptin level lowers in proportion to the amount of aerobic work after four weeks of training in obesity

Leptin values are higher in obesity. Physical exercise reduces fat mass (FM) and decreases leptin levels. Intensity of physical training seems to play a role in reducing circulating leptin. In 16 obese subjects (8 men and 8 women, age 38.6±3.9 years, BMI 35.9±1.8 kg/m(2)), leptin was sampled before and after 4 weeks of controlled training. Eight subjects (4 men and 4 women) performed an aerobic training schedule (Group A), the remainders an aerobic training program with a bout of work beyond the anaerobic threshold (AT) (Group B). Training determined a reduction in leptin levels in both groups, which was significant in Group A (12.2 vs. 27.8 μg/l, p<0.05), even when related to the change in FM (0.372 vs. 0.762 μg/l/kg, p<0.05). FM decreased significantly in Group B when compared to Group A (-7.4 vs. -2.6 kg, respectively, p<0.001). While in Group A the slight loss of FM was aggregated to a significant decrease in leptin levels, the opposite occurred in Group B. In Group A, leptin lowering was proportional to the amount of total work performed (p<0.001, R(2)=0.89). In obesity, a reduction is observed in leptin levels after short-term training, which is seemingly dissociated from concomitant decrease of FM. Aerobic training alone appears to be linked to a greater leptin reduction, which is well correlated with the amount of work performed.

Oxygen uptake and cardiac performance in obese and normal subjects during exercise

Work capacity and cardiopulmonary performance were studied in a group of 11 young obese subjects (BMI 39.9 kg/m2) and a group of 10 young normal subjects (BMI 22 kg/m2). First of all they underwent an incremental cycle ergometer test up to exhaustion. Subsequently, every subject of the two groups performed a constant work rate test at different work loads to estimate cardiac output (Q) below anaerobic threshold (AT) by a 20-second CO2 rebreathing method. Obese subjects had a significantly lower AT (79 vs. 109 W). The ratio between oxygen uptake and heart rate (VO2/HR) (O2 pulse) was higher in the obese group; nevertheless, this variable became significantly lower if we took into consideration the ratio between O2 pulse and kilogram fat-free body mass or kilogram body weight. Both these observations suggest that their reduced work tolerance is linked with a reduced oxygen supply to the muscles in activity. Q increased in similar ways in obese and normal subjects at the preset work rates. The ratio Q/body surface (cardiac index; CI) that we considered in order to try to minimize the differences in body sizes between the two groups, increased less in response to increasing work rates in our obese subjects than in normal subjects. As a whole, these data appear to be in line with a relatively less efficient cardiac performance during progressive work rates in obese subjects.

A comparative study on ferritin concentration in serum and bilateral bronchoalveolar lavage fluid of patients with peripheral lung cancer versus control subjects

OBJECTIVES

To assess the diagnostic value of bronchoalveolar lavage fluid (BALF) ferritin as a lung tumor marker by comparing serum and BALF ferritin concentrations in patients with peripheral lung cancer versus control subjects with benign lung disease, and to examine the theory of ferritin compartmentalization around the tumor area by comparing ferritin concentrations in serum and bilateral (affected and unaffected side) BALF in cancer patients.

METHODS

Four groups of patients were investigated: 10 control nonsmokers, 10 control smokers, 10 smokers with chronic obstructive pulmonary disease (COPD), and 22 patients with primary bronchogenic carcinoma. A bronchoalveolar lavage (BAL) was performed in all subjects (both sides in 13 oncological patients, one side in the others) and samples of BALF and blood were submitted to biochemical analysis.

RESULTS

As a lung tumor marker, BALF ferritin showed 54% sensitivity and 93% specificity and serum ferritin 22% sensitivity and 93% specificity. A significant difference was observed between the two sides in the cancer patients (p = 0.033), and between BALF ferritin from the affected side and COPD patients (p = 0.025). Greater differences were obtained when BALF ferritin in the affected side of cancer patients was compared with values in both control nonsmokers (p < 0.0001) and control smokers (p < 0.001).

CONCLUSIONS

These findings seem to confirm the relative diagnostic value of BALF ferritin as a lung tumor marker and the theory of ferritin compartmentalization. However, further studies are required to clarify the relations between iron and ferritin on the one hand and inflammation, tumorigenesis and host response on the other.

A modified Casson equation to characterize blood rheology for hypertension

A modified Casson equation was established, verified satisficatorily for real conditions and suggested for use in clinical hemorheology. It provides 5 Casson parameters, i.e., Casson yield stress, Casson viscosity, the first critical point of shear rate to cause rouleaux to be broken down into smaller units, the second critical point of shear rate to completely disaggregate into individual erythrocytes, the difference between the two critical points, and also gives two series of the 5 above-mentioned Casson parameters, respectively, under original hematocrit and the standardized hematocrit of 45%. This equation not only reveals the apparent abnormalities of hypertensive patients and normalities of the healthy persons, but also reveals hidden abnormalities for patients with either low or high hematocrit. For 20 cases of hypertensive patients with low hematocrit, the 5 Casson parameters have lower values than control, but the modified equation reveals their hidden higher values than control when their hematocrit is standardized to 45%. For 7 cases of polycythemia complicated with hypertension, the 5 Casson parameters are higher at their original hematocrit, and the modified equation reveals the higher parameters than control also when the hematocrit is standardized to 45%. For 8 cases of polycythemia without complications, the 5 Casson parameters are higher at their original hematocrit than control, while the modified equation still reveals their normalities when standardizing their hematocrit to 45%.

Access to rehabilitation facilities in an unselected hospital population affected by acute stroke

The aim of this study was to evaluate the selection criteria and characteristics of the patients who have access to rehabilitation facilities after having experienced an acute stroke. Between January 1993 and February 1994, 383 patients were recruited in 13 hospitals in Lombardy, and telephonically followed up four months after study entry. The data were collected by members of the Associazione Volontari Ospedalieri (Hospital Volunteers' Association). The 4-month mortality rate was 23%. The primary selection criterion for gaining access to rehabilitation facilities was the degree of disability; the secondary factor was age. Rehabilitation facilities were not available to very severely afflicted or self-sufficient patients, but were preferentially made available to young, partially-dependent patients. A rehabilitative intervention within the first month was made available to fewer than 50% of the patients for whom it was indicated. The absence of care for elderly patients and the delay in its availability for those who actually receive it underline the need for new organisational methods. The data presented here also show that voluntary associations can work as observers of the health service. A more complete study is required in order to understand the real dimensions of the problem and the clinical and social characteristics of the population involved.

[Access to rehabilitation resources for an unselected hospital population of patients with acute seizures]

The study aimed at evaluating selection criteria and basic characteristics of acute stroke patients admitted to rehabilitation programs. From January 1993 to February 1994, 373 patients from 13 hospitals of the Lombardy region were admitted to the study. The 4 months telephone follow-up was performed by the AVO (Hospital Volunteers Association) volunteers. The 4 months fatality rate was 23%. The patients with a higher disability level were prescribed a rehabilitation program. Rehabilitation resources were not available for very severe or dependent patients being mostly the younger and partially dependent patients more often referred to the services. Only 50% of eligible patients received a rehabilitation intervention within 1 month from the index episode of stroke. The lack of caring resources and the long waiting times stress the need for a reorganization of the rehabilitation services. This study also shows that volunteers can play a role of stricter collaboration with doctors and are ready to collaborate in data collection. A larger and more detailed study is warranted in order to gain a better knowledge on the problem and on the clinical and social characteristics of the stroke victims.

Interictal abnormalities of regional cerebral blood flow in migraine with and without aura

Some controversial issues exist whether regional cerebral blood flow (rCBF) changes are present both in migraine with and without aura during the interictal period. For this reason we have studied rCBF characteristics in migraine patients when headache-free. rCBF examinations were performed by the 133Xe inhalation method on 39 normal subjects (24 aged 45 or less and 15 older than 45), on 10 migraine patients with (A+) and on 10 without (A-) aura. The values of each patient were compared with the age-matched control population mean by a computer-assisted mapping system that allows statistical analysis in real time. To compare inter-individual variability 10 subjects, out of 39 normals, constituted an age-, sex- and CO2-matched control group (C). 8 A+ patients and 7 A- showed significant alterations of CBF in comparison with the age-matched control population. The analysis between the age-, sex- and CO2 matched groups showed significant differences of the inter-hemispheric (F = 6.669, p = 0.004) and of the frontal (F = 7.480 p = 0.0008) asymmetries. These data show that in the headache-free period a derangement of the cerebral perfusion is present in both migraine with and without aura, suggesting they are due to the same disease process. Furthermore they show the usefulness of a computer-assisted mapping system, suitable for clinical use, in discovering small alterations in cerebral perfusion.

Haemorheological changes in obese adolescents after short-term diet

Along with other risk factors in coronary heart and cerebrovascular disease, obesity is frequently associated with the development of atherosclerosis, a disease in which the rheological characteristics of blood are important. We studied the influence of weight reduction on haemorheological parameters of 20 obese adolescents (10 female, 10 male; aged 12-17 years) without metabolic and/or cardiovascular diseases. The control group composed 39 health non-obese subjects (19 female, 20 male; aged 13-17 years). At the beginning of the study the mean (+/- s.d.) body mass indices (BMI) of the obese adolescents were 36.0 +/- 5.3 kg/m2 in males and 36.8 +/- 5.0 kg/m2 in females. This was significantly reduced (31.5 +/- 4.9 kg/m2 in males and 32.5 +/- 4.7 kg/m2 in females) after one month following a diet of 1000 kcal/day: 25% proteins, 26% lipids and 49% carbohydrates. Before dieting, plasma fibrinogen level, whole blood viscosity at low shear rates and plasma viscosity were significantly higher in obese patients than in normal subjects, while the microhaematocrit values of the two groups were not significantly different. After dieting, plasma viscosity, the plasma fibrinogen level and the mean erythrocyte aggregation index of the patients decreased significantly compared to basal values, while whole blood viscosity did not change. Our data seem to indicate that short-term diet improves the haemorheological pattern in obese adolescents, probably as a consequence of an important metabolic rearrangement.

Metabolic aspects and sympathetic effects in the obese subject undergoing exercise testing

An impaired plasma Epinephrine (E) and Norepinephrine (NE) response has been described in obese patients during physical exercise. Serum potassium level is influenced either by physical exercise or by the adrenergic system. We studied 12 young obese patients and 12 young controls, all without any cardio-respiratory disorders, who underwent a cycloergometric test with steps of 20 watts every four minutes until exhaustion. During the test we recorded serum potassium levels, E and NE, insulin, glucose and RQ to confirm or not the observation of the reduced adrenergic response in obese patients. During exercise, although both groups reached a not significantly different mean peak value of maximal activity, E and NE increased, more in the controls than in the obese subjects (at peak of exercise 221 +/- 44.1 vs 71 +/- 21.5 pg/ml respectively for E; 2035 +/- 164.8 vs 1141 +/- 313.7 pg/ml respectively for NE). RQ was constantly lower in the obese patients than in the normals both during and after the stress. In both groups potassium increased significantly, but the obese patients had a significantly lower increment at peak of activity when compared to the controls (delta K+: 0.52 +/- 0.11 vs 1.007 +/- 0.17 meq/l respectively, p < 0.05). Insulin and glucose had a behaviour in line with literature in both groups. The behaviour of potassium could be an index of a higher effect of beta-adrenergic system in obese patients than in normals despite the different increases of catecholamines in the two groups. This hypothesis may agree with the preferential metabolic use of fatty acids in our obese patients as indicated by RQ values.

Breathing pattern during and after maximal exercise testing in young untrained subjects and in obese patients

More rapid and more shallow breathing (RSB) than usual, manifested by a lower tidal volume and greater breathing frequency at a given level of ventilation, may be caused by inspiratory muscle fatigue and pulmonary congestion. It has been observed during recovery in young trained adults after very high exercise levels and in middle-aged patients with cardiac disease, after their maximal work load. We studied the breathing pattern during and after exercise testing up to the maximal work capacity in a group of normal untrained, young people and in a group of young obese subjects. RSB was present in normal subjects after a work load which required a maximal O2 consumption near the theoretical value (93% in our cases) and was not present in obese patients probably because neither inspiratory muscle fatigue, nor pulmonary congestion occurs in these subjects. Maximal heart rate at peak of exercise was significantly higher in normal subjects and a direct correlation between delta Vt and maximal heart rate was found in all normal subjects. This is compatible with the hypothesis that RSB is mainly due to an initial interstitial pulmonary edema, as supposed by other authors.

Creatine kinase and creatine kinase-MB isoenzyme during and after exercise testing in normal and obese young people

We report creatine kinase (CK) and CK-MB values during a cycloergometric test up to maximal work capacity in 10 normal subjects aged 20 to 39 years (mean body mass index, 22 kg/m2) and 11 obese patients aged 17 to 42 years (mean body mass index, 41 kg/m2), all without any cardiorespiratory diseases. Total CK was significantly higher in obese patients. The CK-MB was not significantly different between the two groups, except at the first recovery when it was increased in obese patients and decreased in normal subjects. These results could be due to more important total stress of the total musculature, especially cardiac, and especially cardiac musculature in obese patients during a physical effort. Considering the mean values of total CK of our obese patients, it may be possible that they have myocardial damage at percentages of CK-MB less than those of lean subjects generally accepted at more than 4 percent. Moreover, in obese heart patients myocardial distress during exercise testing may be present despite heart rate at peak exercise beneath the theoretic maximal.

Catecholamine-stimulated potassium transport in erythrocytes from normal and obese subjects

The beta adrenergic-modulated Na+/K+ ATPase pump rate of red blood cells was measured in vitro in 18 non diabetic obese patients. After challenge of erythrocytes with beta adrenergic selective agonist Salbutamol, the decrement of the K+ concentration in the suspending medium was assumed to be related to the Na+/K+ ATPase pump rate or to the number of beta 2 receptors. The mean K+ uptake was markedly increased in the erythrocytes of obese patients (1.58 mEq/l SD 0.18) if compared with 38 normal subjects (1.30 mEq/l SD 0.11) and with a population of 30 atopic patients that we have previously reported to have a reduced red cells beta 2 receptor activity (1.09 mEq/L SD 0.11). These results are not consistent with the hypothesis that a reduction in the Na+/K+ ATPase pump rate (at least in red blood cells) may be responsible for decreased metabolic rates leading to obesity. Since the autonomic nervous system is involved in the regulation of the cardiovascular system, it is conceivable that an increased Na+ ATPase pump rate (or supersensitivity) may be responsible of the increased incidence of hypertension, congestive heart failure and unexplained sudden death associated with obesity in some patients.

Cerebral vascular responsiveness in chronic hypercapnia

To assess the responsiveness of the cerebral vessels to chronic hypercapnia, we measured middle cerebral artery flow velocity by transcranial Doppler ultrasound in 20 normal subjects and in 14 COLD patients before and after stimulation by progressive hypercapnia (rebreathing test) or by intravenous administration of an acetazolamide bolus. The results showed no statistically significant difference in baseline flow velocity between the normal subjects and the COLD patients. The COLD patients showed a reduced cerebral vascular responsiveness to both stimuli. Cerebral blood flow is normal in chronic hypercapnia and the mechanism by which compensation is achieved leads to a decrease in cerebral vascular responsiveness.

Influence of erythrocyte aggregability and plasma fibrinogen concentration on CBF with aging

The influence of the rheological properties of the blood on cerebral perfusion is still unresolved. Data on normal subjects are lacking and difficulties arise regarding the effect of blood viscosity owing to its close relationship with hematocrit. For these reasons we have studied the relationship between two rheological hematocrit-independent parameters and CBF in normal subjects of various ages. 36 normal volunteers, aged 20-74, free from risk factors, have been studied. CBF was measured by the Xenon inhalation method. Erythrocyte aggregability was expressed as Mean Erythrocyte Aggregation Index (MEA). Plasma fibrinogen concentration was evaluated by the coagulative method in 26 subjects. No correlation was found between CBF and MEA or fibrinogen in the subjects under the age of 45. A significant negative correlation was found between CBF and MEA (p = 0.015) and between CBF and fibrinogen (p = 0.011) in the subjects over 45. These data show that cerebral perfusion is influenced by the rheological properties of the microcirulation only with aging. We suggest that a "rheological autoregulation" exists and that it works properly in youth, only to be lost with physiological aging. This finding can be of significance in the pathogenesis of cerebrovascular disease processes in humans.

Work capacity and cardiopulmonary adaptation of the obese subject during exercise testing

Twelve obese patients (six male subjects) aged 17 to 42 years with a mean body mass index (BMI) of 40 kg/m2 and 12 normal subjects (six male subjects) aged 19 to 39 years with a mean BMI of 22 kg/m2 underwent a cycloergometric test until exhaustion to assess work capacity and cardiopulmonary adaptations of the two groups. Minute ventilation, expiratory gas concentrations, and heart rate, together with anaerobic threshold (AT) were determined in each subject during the test. The same subjects were then submitted to normocapnic hyperpnea at rest to assess the oxygen cost of breathing. We found that in the obese patients, the maximal sustainable work rate was not different from that of controls (120 vs 136 W) while AT was significantly lower (78 vs 110 W). Nevertheless, there was no difference in maximum VO2 and in VO2 at AT levels (expressed in milliliters per minute) indicating that cardiac, pulmonary, vascular, and muscle performance did not differ from obese to normal subjects. Greater muscular effort was needed by obese patients when moving their heavier legs and less when doing external work with a decreased gross mechanical efficiency and an identical net mechanical efficiency between the two groups.

[Focus. An expert system for the clinical diagnosis of the location of acute neurologic events]

Focus is an expert system developed to diagnose, by the findings on neurological examination, the anatomic location of an acute neurologic event. The inference engine uses a forward tracking algorithm and a rule based data base that includes associations of neurological signs with specific anatomic areas. Focus is linked to a data base in which all personal cases and final diagnoses confirmed by laboratory studies are stored. This makes it possible to assess the validity of the system's diagnoses and use personal cases as additional example to the revision of the rules. The program is easy to use and runs on MS-DOS microcomputer. Furthermore the diagnostic rules are accessible so Focus may furnish an interactive teaching device.

CBF side-to-side asymmetries in stenosis-occlusion of internal carotid artery. Relevance of CT findings and collateral supply

Cerebral blood flow (CBF) was studied at rest by 133-Xenon inhalation method in 15 normal subjects, in 10 patients with cerebral infarction and normal angiograms of major cerebral arteries and in 28 patients with unilateral stenosis-occlusion of the internal carotid artery (ICA), with or without cerebral infarction. All the normals and 20 patients with ICA stenosis-occlusion were tested again after cerebral vasodilatation induced by an intravenous bolus of acetazolamide. At rest the patients with cerebral infarction, irrespective of whether ICa stenosis-occlusion was present or not, showed abnormal side-to-side CBF asymmetry. After cerebral vasodilation variations in side-to-side asymmetry were shown to depend on the inefficiency of the collaterals and not on the degree of ICA obstruction or on the presence of cerebral infarction. These data indicate that at rest side-to-side CBF distribution is influenced more by the presence of an ischemic zone than by a ICA stenosis-occlusion and that under these circumstances the hemodynamic effect of the vascular stenosis cannot be assessed. After cerebral vasodilatation a subset of patients--irrespective of the degree of ICA obstruction and of whether or not cerebral infarction is present--with true cerebrovascular insufficiency can be isolated.

Relationship between body mass and tolerance to physical stress in obese patients

Eleven obese patients, 5 males; age: 17-42; body mass index (BMI): 40; % of ideal weight: 187%, and 10 normal subjects (5 males; age: 19-39; BMI: 22; % of ideal weight: 103%), both groups without heart and respiratory disorders, underwent a cycloergometric test with subsequent 20-watt increases every 4 min until exhaustion. During the test, ventilation/minute, expiratory gas concentration and heart rate were measured, and the anaerobic threshold (AT) was determined in each subject. The obese patients showed a significantly lower AT than normal subjects (p less than 0.01); showing values which decreased with the increase in the grade of obesity expressed in BMI or in percent of their ideal weight. Moreover, in the obese patients, the O2 consumption (VO2) had significantly increased compared to that of normal subjects at no resistance and at all work levels. The negative correlation between the AT value and the BMI in obese patients can attribute their increase in VO2 during stress to (1) the inertial overloading caused by obesity especially considering the adipose tissue of their legs, or (2) to their level of 'fitness' being lower than that of normal subjects.

Determination of T lymphocyte subpopulations in patients with lung cancer. A comparison between lung lavage and peripheral blood by monoclonal antibodies and flow cytometry

In order to determine whether the alterations of immunoregulatory T cells described both in smokers and in patients with lung cancer occur in the deep lung as well as in peripheral blood, we analyzed T lymphocyte subpopulations in bronchoalveolar lavage (BAL) and in the blood of 12 patients with untreated lung cancer and of 8 controls. The immunocompetent cellular population of BAL fluid analyzed by differential cell count of alveolar macrophages, lymphocytes and neutrophils did not show considerable differences in the two groups studied. By contrast, the analysis of BAL T lymphocytes and their subsets showed significant alterations in patients compared with controls: a percentage increase of OKT3+ and OKT8+ lymphocytes and a decrease of the OKT4+/OKT8+ ratio was found in both the involved and uninvolved lung of patients. The immunologic pattern of T lymphocytes in blood did not show significant differences between patients and controls. Our data indicate that alterations in immunoregulatory T cells in lung cancer are more pronounced in BAL fluid obtained from both lungs than in peripheral blood.

Evaluation of the intensity and duration of the bronchodilatory action of fenoterol-ipratropium bromide in combination compared with terbutaline and placebo in patients with chronic obstructive lung disease

The effect obtained using terbutaline and Duovent was studied in a group of 16 patients with chronic obstructive lung disease. The drugs were administered by aerosol in doses based on spirometric indices of flow and lung capacity. The results obtained confirm the efficacy of the two drugs in improving gas flow. This improvement persisted for 6-7 h after administration. Comparison of the two drugs has shown that as far as FVC is concerned, the improvement obtained with Duovent is longer-lasting than that with terbutaline. There were no side-effects.

The effect of intravenously administered salbutamol on serum potassium in asthmatic and nonasthmatic atopic subjects

The role of adrenergic mechanism in the pathogenesis of allergic disease is controversial. Recent experimental and clinical reports have suggested that beta-adrenergic blockade impairs and beta stimulation enhances extrarenal potassium uptake in humans. This led us to study the effect of the intravenous administration of salbutamol, a specific beta-2-adrenergic agonist, on serum potassium in 9 healthy subjects and in 23 patients with allergic asthma and/or rhinitis. Serum potassium fell significantly and reached a peak decline at the end of venous infusion in all the normal subjects. Seventeen atopic subjects showed a lower or absent serum K+ decrement: there was no difference between asthmatic and rhinitic patients. There was no relation among the salbutamol-induced serum potassium decrement, serum glucose increment, blood pressure and heart-rate changes, and nonspecific bronchial reactivity. These findings suggest that beta-2-adrenergic hyporesponsiveness is present only in some allergic patients.

[Hemorheologic characteristics in beta-thalassemic homozygotes before and after splenectomy]

In a group of 36 homozigous beta-thalassaemic children we studied the effect of splenectomy on hemorheologic characteristics. The aim of the work was to evaluate the importance of such operation either on anemia or on erythrocyte deformability. Whole blood viscosity was measured with a Brookfield Microviscometer (LVT) and erythrocyte deformability was evaluated with the erythrocyte filtration technique using policarbonate membranes. The more the erythrocyte deformability decreases, the more the erythrocyte filtration rate decreases. Our data show that splenectomized children, have worse hemorheologic characteristics according to the longer survival time of pathological red blood cells in spite of their reduced deformability. This behaviour can be modified only by blood transfusion that we have seen to be able to reduce whole blood viscosity and to increase erythrocyte filtration rate in splenectomized children. We think that splenectomy must be delayed as long as possible so that hemodinamyc conditions cannot be worsened. An hemorheologic monitorage could be useful for diagnostic and prognostic evaluations both in splenectomized and not splenectomized children.

M-mode subxiphoid echocardiography in assessing pulmonary hypertension. Its usefulness in chronic obstructive pulmonary disease

12 patients (9 males, 3 females; aged 35-63 years, mean 55) with chronic obstructive pulmonary disease (COPD) were studied in order to determine the correlation between the values of pulmonary arterial pressure and the M-mode echographic size of the right pulmonary artery (RPA) from the subxiphoid approach. Both the largest (systolic) and smallest (diastolic) size of the vessel were considered, and both were corrected for body surface area ('index size' - PA/BSA). The reliability of this echographic size is supported by the evidence that the tract of the pulmonary artery considered in this study is perpendicular to the ultrasonic beam. Both the systolic and diastolic size of RPA correlated with the systolic, diastolic, and mean pulmonary arterial pressure, detected by catheterization. Measurements of RPA size were made from the suprasternal approach in 8 patients out of 12. The size of RPA from the subxiphoid approach was also estimated in 21 normal subjects, serving as controls. Measurements of RPA size from the suprasternal approach were made in 12 of these subjects. Both the systolic and diastolic size of RPA from the subxiphoid approach correlated with the systolic and diastolic size of the suprasternal view in patients and in normal subjects. Subxiphoid M-mode echocardiography seems to be a valuable noninvasive technique in assessment of pulmonary hypertension, particularly in patients affected by COPD.

Potassium tolerance and bronchial reactivity in asthmatic and nonasthmatic atopic subjects

Abnormal autonomic nervous system responsiveness may contribute to the pathogenesis of allergic diseases. Therefore, we measured the beta-adrenergic systemic (metabolic) responsiveness by means of acute potassium load in 10 normal healthy subjects and in 19 patients with allergic asthma and/or rhinitis. Ten allergic patients showed a greater potassium increment, as in normal subjects, when potassium was infused in the presence of propranolol. There was no difference between asthmatic and rhinitic patients. We then examined the relation between the response to potassium tolerance and the nonspecific, nonpharmacological bronchial reactivity in response to inhalation of ultrasonically nebulized distilled water. Some allergic patients showed bronchial hyperreactivity, while others did not show a difference compared with the controls; there was no significant difference between asthmatics and rhinitics, and there was no relation between nonspecific bronchial reactivity and potassium load tolerance. These findings suggest that systemic beta-adrenergic hyporesponsiveness may be present only in some allergic patients. There is no demonstrable relation among atopic state, nonspecific, nonpharmacological bronchial reactivity, and systemic beta-adrenergic hyporesponsiveness.

Detection of circulating DNA in plasma of patients with pulmonary embolism by counterimmunoelectrophoresis

In order to confirm the usefulness of free plasma DNA detection in the diagnosis of pulmonary embolism (PE), we have studied 16 patients with PE, 33 with various diseases, and 13 normal subjects. Free plasma DNA was detectable in 15 of 16 patients with PE (94%) and in 3 control patients, but never in plasma from normal subjects. In most cases, DNA was detectable until the 10th day after PE. In conclusion, counterimmunoelectrophoresis is a rapid, inexpensive and specific test which may be used as an exclusion test in the detection of patients suspected of having PE, who will have to undergo more extensive evaluation.

Pressure available for expiration in chronic airway obstruction

The pressure generated at 0.1 s after the onset of expiration measures the rate of rise of expiratory pressure potentially available for expiration. P0.1e increased with increasing the frequency of breathing and was higher in chronic obstructive pulmonary disease (COPD) patients than in controls. In normal subjects breathing under resistive load P0.1e became similar to that of patients for a given respiratory frequency. P0.1e consistently increased as the load and/or the frequency of breathing were raised. Expiratory pressure depends on elastic recoil of the respiratory system, nevertheless the action of neurally controlled respiratory muscles influence the rate of rise of expiratory pressure. The decrease of expiratory braking action by inspiratory muscles (-Pmusi) influence the rate of pressure rise in the first part of expiration, whereas the contraction of abdominal muscles (-Pmuse) increases P0.1e later from onset of expiratory occlusion. These compensatory reflexes are vagally mediated and are presumed to originate in stretch receptors. In COPD patients the braking action of inspiratory muscles was smaller and the facilitating action of abdominal muscles was higher than in controls. Both expiratory braking decay and expiratory activity increase with the rise of breathing frequency or with the increase of respiratory airflow resistance.

[Behavior of glutamic-pyruvic transaminase during the clinical course of acute myocardial infarct]

The increase in serum Alanine-aminotransferase (SGPT) levels in 104 patients with acute myocardial infarction is studied. The time course of serum enzyme changes shows two peaks of activity: in the first days after infarction and at the end of the second week of the disease. The clinical significance of this finding is discussed.

Effects of isovolumetric venesection on blood viscosity, on red cell deformability, and on arterial flow velocity in chronic respiratory failure with secondary polycythemia

Normovolemic hemodilution produced by isovolumetric venesection was done in 8 patients with polycythemia and respiratory failure secondary to chronic obstructive pulmonary disease. The 'deformability index' was studied by means of a filtration technique. The blood flow velocity in ascending aorta and right pulmonary artery was also studied by means of ultrasonic Echo-Doppler technique. The procedure showed in all patients an increase of oxygen tension and a decrease of carbonic gas tension in arterial blood. At the same time it was possible to demonstrate an improvement of red cell deformability and an increase of arterial flow velocity. Isovolumetric venesection is an important procedure in the management of patients with polycythemia secondary to respiratory failure.

Respiratory function 8 years after a diagnosis of peripheral airways disease

A program of screening for airways obstruction was designed to examine: (1) the precision and the reliability of the proposed tests (2) the evolution of respiratory impairment in 69 subjects, 8 years after a diagnosis of peripheral (small) airways obstruction. The tests that exhibit very good reliability are: vital capacity, total lung capacity, 1-second forced expiratory volume, single breath CO diffusion capacity, curvilinearity score; and the ratio of closing capacity to total lung capacity. 39% of smokers and 15% of nonsmokers developed central airways obstruction 8 years after the diagnosis of peripheral airways disease. These results confirm the hypothesis that small airways may be regarded as a noisy rather than a silent zone.

Effect of hematocrit on the blood viscosity of patients with chronic respiratory failure and secondary polycythemia

The blood of patients with chronic global respiratory failure and polycythemia exhibits higher viscosity than that of normal subjects. Plasma changes have been excluded as causal factors. The viscosity of whole blood, plasma and blood after correction of hematocrit (Ht; 45%) with autologous plasma, has been determined. The results indicate that in such patients the increase in Ht is not the most important factor affecting the rheological properties (increased viscosity) of blood. A high Ht value may be only pat of the mechanism that increases the blood viscosity of patients with chronic obstructive pulmonary disease. There is evidence that other factors are responsible for increased blood viscosity in chronic respiratory failure.

Small airways disease: a trial of an easy functional discrimination of preclinical emphysema

In the genesis of small airways obstruction (SAO) we have to consider two alterations with different prognoses: the first, in which the obstruction depends on a reduction of the diameters of the small bronchi (i.e. with prevalent 'intrinsic mechanism)'), is reversible; the second, probably irreversible, is due to pulmonary emphysema in its pre-clinical stage. It is useful to distinguish between these two mechanisms by means of functional tests which are easily applicable in epidemiological screening. We have studied, by means of different lung mechanics tests, 5 normal, male, non-smoking subjects (N) and 10 male smokers considered to be affected by SAO. Several theoretical considerations, experimental data and prospective studies suggest that under various tests of easy execution for a screening program there are some which have, in some cases, a prognostic value and seem to be coupled to a qualitative meaning: this is the case for delta N2 which is significantly greater in subjects of the extrinsic group where the abnormality is considered irreversible. Some other tests are very sensitive to detect SAO subjects by they are lacking in specificity and in prognostic meaning (CV, VEmax, FDC). Finally, other tests [maximal mid-expiratory flow (MMEF) and residual volume (RV)] seem to have a prognostic value only because they indicate an advanced stage of the illness, not depending on the kind of the affection (SAO Ex or SAO In).

Maximal frequency of breathing at various tidal volumes in airways obstruction

To determine the relative importance of control system and of mechanical and metabolic properties of the motor system on the maximal frequency of breathing (1/t) at various tidal volumes (VT), we have studied the relationship between cycle period (t) and tidal volume in 10 normal subjects, in 9 patients with chronic obstructive lung disease, and in a normal subject breathing against different resistive loads. The results, expressed according to the equation t = t0 + b VT (where t0 represents the time required for a breathing cycle at zero VT and b means the additional time required for a breathing cycle with a VT equal to vital capacity), indicate that t0 is independent from the load either in unloaded or loaded normal subjects or in obstructive patients. In fact, although b was found significantly different, t0 remained essentially constant. These findings suggest that the level of maximal voluntary ventilation may be mainly related to metabolic and mechanical properties of the motor system (muscles of breathing and load imposed on them).

Relationship between urine acidification and intracellular pH in respiratory acidosis

The renal net acid excretion (NAE), the blood pH (pHe), the total body intracellular pH (pHi) and the urinary pH (pHu) were calculated in 10 patients with chronic obstructive lung disease and hypercapnia and in 5 normocapnic subjects. The mean value of NAE was significantly higher in hypercapnic subjects than in normocapnic ones. pHe was significantly lower in hypercapnic than in normocapnic subjects. The differences of pHi and pHu between normo and hypercapnic subjects were not significant. NAE is significantly correlated with PaCO2, pHe, pHu and pHi in all the subjects considered together. H+-secretion probably depends on the H+-availability and pHi of tubular cells, but from our results it is not possible to confirm this relationship, because the method used for pHi is fundamentally a measure of muscle-pHi.

Peripheral pulmonary wedge angiography in chronic obstructive pulmonary disease. Relationship to pulmonary function, chest x-ray film, and hemodynamic data

Peripheral pulmonary wedge angiographic studies can investigate only limited areas of the pulmonary vascular bed; nevertheless, this technique is very useful in emphasizing the morphologic changes of small vessels (less than 1 mm in diameter) in pulmonary emphysema. The aim of this work is to determine the relationship between peripheral wedge angiographic appearances and pulmonary function, the chest x-ray film, and hemodynamic data in patients with chronic obstructive pulmonary disease. Three healthy subjects, four patients with type-A chronic obstructive pulmonary disease, and eight patients with type-B chronic obstructive pulmonary disease were studied. Among the tests of pulmonary function, only a marked reduction (less than 60 percent of predicted) of the diffusing capacity for carbon monoxide is always indicative of severe widespread emphysema. No relationship was found between hemodynamic data and peripheral wedge angiographic findings. Some agreement resulted between the chest x-ray film and peripheral wedge angiographic abnormalities only in patients with type-A chronic obstructive pulmonary disease; on the contrary, in patients with type-B chronic obstructive pulmonary disease, both false-positives and false-negatives were noted.

Prospective study of airway obstruction in a population with small airway disease

In this paper, we discuss results showing an increase of bronchial obstruction due to exposure in an iron foundry. The research has been conducted in two steps: in the first, we selected a sample of 100 subjects, all working in the iron foundry, who were affected only by small airway obstruction. In a second step, 30 months later, 99 of these subjects were re-examined and the present airway condition determined. In 43 subjects we found abnormal results of the tests indicating total airway obstruction after the 30 months. After properly accounting for ageing, we found that even in the subsample of non-smokers a deterioration had occurred, showing an effective contribution of environmental pollution. The use of RV, MMEF, CV, DLCO for detecting small airway obstruction is evaluated. The combination of RV, MMEF and CV is the most efficient mosaic of tests for the selection of subjects with small airway obstruction (89%) and with high probability of developing total airway obstruction (44%).

Early discrimination between intrinsic and extrinsic factors in chronic obstructive lung disease

15 subjects, divided into (1) normal, (2) with small airway obstruction (SAO) and (3) with chronic obstructive lung disease (COLD), were studied to understand the mechanism of the obstruction. The curves of maximal expiratory flow versus static pressure are particularly useful for this purpose, when we have a SAO. In fact, only at this early stage, we can identify by this way two different groups: subjects obstructed by a pure extrinsic mechanism, and subjects obstructed by a pure intrinsic mechanism.

Drive and performance of ventilatory system during rebreathing

In eight normal subjects, eight patients with asthma, and six patients with chronic obstructive lung disease, the first derivative of occlusion pressure at FRC during rebreathing has been studied. The maximal dP/dt was always lower in patients. Such a behavior may depend on reduced neuronal discharge as well as on reduced effectiveness of the contraction of the respiratory muscles. Though (dP/dt)max. may provide a reliable measure of the sensitivity of the respiratory center only in a homogeneous group, the results of plotting its value against ventilation and end-tidal Pco2 confirm the failure of the thoracomuscular system to convert the output of respiratory centers into increase of pulmonary pressure and ventilation.

Clinical value of rebreathing test in obstructive lung diseases

The ventilatory response to CO2 inhalation, using rebreathing method, was studied in normal subjects and in patients with bronchial asthma and chronic obstructive lung disease. The patients with lung disease had flatter CO2 response curves. However, it the ventilation was expressed as a fraction of the maximal voluntary ventilation, the difference between normal subjects and patients disappeared. The reduced ventilatory response of these patients may be of mechanical origin and not depending on reduced CO2 sensitivity. The high lung volume of these patients may be the mean factor of the mechanical disadvantage of thoracomuscular system.

Simple parametrizations of maximum expiratory flow-volume curves

Four elementary mono-compartmental lung models yield parametrizations of Maximal Expiratory Flow-Volume curves of normal subjects. The respective analytical functions are fitted to the measured curves and the mathematically derived ventilation indices are compared with standard measured data. While individual values of resistance and compliance seem devoid of a simple physical interpretation, their product indeed matches the models.