Air pollution by gasoline exhaust fumes: effect on platelet function and blood viscosity.

Air pollution induced by automobile exhaust fumes seems to be involved in increased cardiovascular and respiratory morbidity. The effects of inhalation of such pollutant gases on platelet function and blood viscosity have not been sufficiently investigated, even if these parameters seem to be in strict correlation with cardiovascular function. Twelve healthy non-smoking volunteers were exposed for 30 minutes in a closed room to air polluted by automobile fumes. Platelet aggregation, blood viscosity, HbCO levels and P50 STD were determined before and after exposure. Cardiovascular parameters (blood pressure, heart rate and ECG) were also measured. At the end of the test, HbCO levels were significantly increased, but P50 STD was significantly reduced; an impairment of both platelet function and blood viscosity was observed. No significant changes in cardiovascular parameters were recorded. The decreases in platelet aggregation and blood viscosity were not directly correlated with either the increase in carbon monoxide levels or with the reduced P50 STD levels. It can be reasonably concluded that gasoline exhaust fumes could have been responsible for the observed alterations.

Pathophysiological study of the non-insulin-dependent phase of type I diabetes mellitus.

The usual practice of considering type I diabetes synonymous with insulin-dependent diabetes has been criticized. Since type I diabetes can have a non-insulin-dependent phase (pre-type I diabetes and/or honeymoon) the differentiation of two main types of diabetes according to insulin-dependency is not absolute. We studied the insulin, C-peptide and glucagon responses to various tests (OGTT, IVGTT, glibenclamide test, mixed meal tolerance test and ITT) performed during the non-insulin-dependent phase of 3 young patients (range 8-18 years) who developed ketosis 12-24 months after the discovery of fasting hyperglycemia, and in 6 patients (age 15-23 years) who presented a remission phase 4-6 months after the sudden clinical onset of type I diabetes. An insignificant insulin and C-peptide increase following i.v. glucose was observed in all patients, whereas the B-cell response to both oral glucose and other secretagogues was preserved, although at a subnormal level. In the three hyperglycemic and preketoacidotic patients the basal levels of glucagon were low and no significant increase after secretagogues was seen. Sensitivity to exogenous insulin in all patients was good. Thus, B-cell response in our patients was reminiscent of the differential responsiveness to various stimulants in the early stage of type II (non-insulin-dependent) diabetes. These results suggest that type I and type II diabetes can be characterized by the same functional B-cell defect during a period of their natural history.

Is the common presence of glucose intolerance in old age a reliable index for the subsequent occurrence of fasting hyperglycemia?

The aim of the present study was to verify the validity of diagnostic criteria developed by the NDDG for the diagnosis of diabetes mellitus in old age. One hundred and fifty-one ambulatory old (range: 66-77 years) subjects (group A) underwent OGTT showing the following results: 33% normal, 12% non-diagnostic, 23% impaired glucose tolerance (IGT), 32% diabetic-type tolerance (DT). In addition, 84 subjects (group B) selected from 1978 to 1982 (42 aged 51-60 years, 30 aged 61-70, and 12 aged 71-80) with abnormalities of glucose tolerance during OGTT (IGT or DT) were asked to control their fasting plasma glucose every month during 1984. In group B a significant correlation between DT and subsequent development of fasting hyperglycemia was observed only in the subjects of the 6th and 7th decades of age. On the contrary, no subjects aged 71-80 years developed fasting hyperglycemia. The authors suggest that a high prevalence of abnormalities in glucose tolerance according to NDDG exists in old age which cannot be considered evidence of a true diabetes mellitus being unpredictive of a progression towards fasting hyperglycemia.

[Effects of low O2 tension on platelet aggregation]. / Effetti della bassa tensione di O2 sull'aggregabilita' piastrinica.

Several studies in animals suggest a link between haemocoagulative patterns and blood gas changes. Furthermore platelet functions seem to be affected by O2 concentrations. In the present study we have evaluated "in vitro" the effect of low PO2 concentrations on platelet aggregation in man. In 15 normal subjects (mean age 32 +/- 5) platelet aggregation ADP (end conc. 1,25 microM) and collagen induced 2 micrograms/Ml) was determined before and after exposition to low PO2 concentrations (O2 conc. 5,04%). The results show that low PO2 concentrations determine a significant increase (P less than 0,001) of platelet aggregation as compared to controls. Although the mechanism of the direct influence of PO2 concentrations upon human platelet is unclear, this finding suggest new therapeutic approaches in chronic lung obstructive diseases.

P50 values determined by tonometry and by simplified techniques.

Actual determination of the position of the oxygen hemoglobin dissociation curve (P50) was compared to three methods of estimating P50 in 39 patients with various diseases. There was a significant correlation between determined and estimated P50 values (P less than 0,001) for each of the methods studied. The data suggest that calculating P50 is reliable and may replace the need for actual measurement.

The oxygen-release capacity of red blood cells in insulin-dependent diabetics after artificial pancreas.

Oxygen-release capacity of the red blood cells was investigated in non-acidotic insulin-dependent diabetics before and after the achievement of strict metabolic control with the aid of the artificial pancreas. P50std (oxygen tension at 50% oxygen saturation) values were low in basal condition and returned to normal after the 24-h treatment period. No significant changes were observed in the content of red cell 2,3-diphosphoglycerate nor in the acid-base balance. Only the labile form of glycosylated hemoglobin showed significant decreases after treatment. These results suggest that insulin-dependent diabetics may have a state of relative tissue hypoxia which can be easily overcome by the achievement of strict metabolic control.

[Effect of pentoxifylline on the dissociation curve of oxyhemoglobin]. / Azione della pentossifillina sulla curva di dissociazione dell'ossiemoglobina.

In 9 subjects with peripheral vascular insufficiencies the AA. have studied the behaviour of the oxyhaemoglobin dissociation curve before and after pentoxyphilline infusion. After this drug no variations were observed as it regards MCHC, 2-3-DPG and so on; however a positive correlation was found between 2-3-DPG and the Hill number. These results suggest that 2-3-DPG may influence the Hill number (which is the expression of the gradient of the oxyhaemoglobin dissociation curve) and therefore may interfere with O2 transport.

[Behavior of hemodynamic and blood-gas parameters after intravenous salbutamol]. / Comportamento dei parametri emodinamici ed emogasometrici dopo salbutamolo per via endovenosa.

The haemodynamic effects of salbutamol were studied in 14 patients with chronic obstructive lung disease with a single dose of 100 and 200 gamma, administered by i.v. injection. The results of study revealed salbutamol intravenous injection significantly increases heart rate, cardiac index and decreases vascular systemic resistance. There was no significant change in blood gas tensions. This study indicates that salbutamol produces variation in preload and afterload by a direct action on vascular smooth muscle.

[Polygraphic study of systolic rates after intravenous administration of salbutamol]. / Studio poligrafico degli indici sistolici dopo somministrazione endovenosa di Salbutamolo.

The effects of salbutamol on the polygraphic pattern were studied in 10 patients with chronic obstructive lung disease. Salbutamol, administered by i.v. injection in a single dose of 100 gamma, caused an increase of heart rate, a decrease of PEP (by decrease in the TCI), a decrease of the Wessler's index and an increase of ejection fraction. These results suggest that salbutamol produces an improvement in cardiac function either by a direct inotropic action or by an afterload decrease.

[Echocardiographic assessment of left ventricular function after intravenous administration of salbutamol]. / Valutazione ecocardiografica della funzionalità ventricolare sinistra dopo somministrazione endovenosa di salbutamolo.

Changes in the main parameters of left ventricular function by comparison with the baselines were examined echocardiography in 11 patients after a single i.v. dose of salbutamol. The results suggest that salbutamol certainly has peripheral vascular effects leading to changes in ventricular volumes. The drug also appears to exert a positive intropic action, as shown by the changes it induced in EF and, more particularly VCF values.

[Thromboelastographic patterns in patients suffering from chronic obstructive lung disease after hyperventilation]. / Rilievi tromboelastografici in broncopneumopatici cronici sottoposti ad iperventilazione.

In an our previous study we studied the influence of O2 therapy administration on the thromboelastographic pattern of patients suffering from chronic obstructive lung disease. We showed that basal hypocoagulability of our patients became normal after O2 administration. In this study we refer the thromboelastographic pattern observed in patients suffering from the same disease before and after hyperventilation. We don't find any changes about total coagulability either in patients or in healthy subjects after hyperventilation. Therefore we suggest that the absence of any changes is due to PCO2 and pH variations that occur at the same time of PO2 modification during hyperventilation; PCO2 and pH variations may influence the haemoglobin oxygen affinity and annul the effect of the increase PO2 on the tissue oxygenation. We suppose that the increase of patients suffering from chronic obstructive lung disease, is due to decreased fibrinolysis or to increased production of prostacycline induced by hyperventilation.

[PO2 and PCO2 after nifedipine administered by the sublingual route in hypertensive patients (author's transl)]. / Comportamento dei parametri emogasometrici dopo somministrazione di nifedipina per via sublinguale in soggetti ipertesi.

The Authors have examined the PO2 and PCO2 of peripheral arterial blood in 10 hypertensive subjects before and after 20 mg of nifedipine administered by sublingual route. A PaO2 decrease and a light increase of PaCO2 were observed; this pattern, if considered together with the increase of CO2 and the decrease of pulmonary resistance, may be attributed to a greater perfusion of those districts having a low V/Q ratio.

[Thrombelastographic pattern in chronic bronchopneumonia patients placed on oxygen therapy]. / Rilievi tromboelastografici in broncopneumopatici cronici sottoposti ad ossigeno terapia.

The thromboelastographic pattern in chronic obstructive lung disease as compared to normal group during O2 administration was evaluated. The results stressed that the basal hypocoagulability of pathological subjects had become normal after O2 administration. No significant change in the group of normal subjects was observed.