Nocturnal continuous measurement of blood pressure in sleep apnea syndromes. Comparison between normotensive and hypertensive patients

Sleep apnea syndrome and systemic hypertension are frequently associated but their causal relationship is unclear. We compared the oscillations of systemic blood pressure and heart rate during polysomnography in 8 normotensive subjects (2 females) and 5 hypertensive (supine awake blood pressure: 165 +/- 7/96 +/- 5 mmHg) without treatment. Their ages (normotensive: 52.1 +/- 11.0 yrs, hypertensive: 51.2 +/- 6.4 yrs) and body mass indices (32.6 +/- 9.6 kg/m2 vs 33.2 +/- 5.2 kg/m2 respectively) were not statistically different. Systemic blood pressure was continuously monitored by a non invasive digital plethysmography (Finapres). Both groups had similar respiratory events indices (normotensive: 45.2 +/- 18.1/hr, hypertensive: 48.4 +/- 20.5/hr) and minimal oxygen saturations (79.4 +/- 9.1% vs 82.4 +/- 7.0% respectively). During apneas in slow-wave sleep were observed the minimal values for systolic and diastolic pressures which were significantly higher in hypertensive than in normotensive (138.2 +/- 9.6/83.2 +/- 16.1 mmHg vs 105.9 +/- 11.1/60.5 +/- 10.9 mmHg respectively). During resumption of ventilation maximal blood values were recorded which were also higher in hypertensive than in normotensive (185.0 +/- 13.8/113.2 +/- 21.5 mmHg vs 155.9 +/- 19.8/88.7 +/- 17.1 mmHg respectively) (p less than 0.05). Although absolute variations of blood pressure were similar, relative changes in systolic pressure were significantly higher in normotensive (p less than 0.05). Maximal heart rate was 76.8 +/- 6.2 bpm in normotensive and 76.6 +/- 3.9 bpm in hypertensive during resumption of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of Lagomorpha in the wild cycle of Rickettsia conorii in Salamanca (Spain).

In an endemic zone for Mediterranean spotted fever levels of antibodies to R. conorii were evaluated in serum samples from wild rabbits (Orytolagus cuniculus) and hares (Lepus granatensis) using an indirect microimmunofluorescence antibody test. The results of the study show that the wild rabbit may carry out in this area an important function in the maintenance of R. conorii in nature.     

Clinical and laboratory features of type 1 diabetic children at the time of diagnosis.

The French incidence study has registered all new cases of Type 1 diabetic children under 20 years of age, from a population of 2.32 million, in an exhaustive and prospective manner. Three hundred and forty cases were identified between 1 January 1988 and 31 December 1989, yielding a mean annual incidence rate 7.3 per 10(5). The lowest rate was observed in the youngest age group (0-4 yr: 4.1 per 10(5)) and the highest around pubertal development (10-14 yr: 11.5 per 10(5)). Details of the previous personal and family history, and the clinical and biological pictures of the disease at diagnosis were recorded. Almost 8 per cent of the children had a first-degree relative with Type 1 diabetes. Polyuria, weight loss, fatigue and abdominal pain were the most frequently reported symptoms, which were of median duration 4.4 months. Mean weight loss before diagnosis was 9.4 +/- 6.8 (+/- SD)% of body weight and was not significantly related to age. Ketonuria was detected in 83.8 per cent and acidosis (total CO2 less than or equal to 18 mmol l-1, if measured) in 48 per cent of the cases. Ketonuria and acidosis were significantly more frequent in the younger age group than in the rest of the group (p less than 0.001).     

Soluble factors released by the target organ enhance the urokinase-type plasminogen activator activity of metastatic tumor cells

The ability of tumor cells to respond to microenvironmental factors present in the target organ may be necessary for successful metastasis. Many studies suggest that urokinase-type plasminogen activator (u-PA) has a significant role in several steps of the metastatic process. In previous work it had been observed that lung conditioned media stimulated the migration and growthin vitro of cells from a murine mammary adenocarcinoma (M3) with moderate lung metastasizing potential. In the same experiments liver conditioned medium exerted a marked cytostatic effect on M3 cells. The aim of the present work to investigate whether conditioned media from lung, kidney or liver, were able to modulate u-PAin vitro secretion by these murine M3 cells. Secreted u-PA measured by fibrinolytic assay, was significantly increased only when M3 primary cultured cells were treated for 24 h with lung conditioned media prepared from normal mice or from mice bearing a small tumor. Exposure to kidney or liver conditioned media did not modify the u-PA secretion pattern already shown by the tumor cells. The activity shown by lung conditioned media seemed to be specific for these syngeneic tumor cells, as no effect was observed on murine embryo cells. These results suggest that soluble factors released by the target organ could specifically induce tumor cellsin vivo to enhance the production of degradative enzymes, thus facilitating the last steps of the metastatic cascade.     

Resistance to insulin mediated glucose disposal in obese subjects: respective effect of lipid metabolism and glycemia.

The present study was designed to assess the respective effect of altered lipid metabolism and hyperglycemia on glucose metabolism in vivo in obese subjects. Six young obese non-diabetic volunteers were studied on four occasions during hyperinsulinemic clamp, twice during euglycemia and twice during hyperglycemia, with or without the infusion of beta-pyridylcarbinol, an inhibitor of lipid metabolism. Glucose oxidation was calculated from continuous respiratory exchange measurements, and glucose storage was obtained as the difference between total glucose disposal and glucose oxidation. Two-way analysis of variance (with interaction term) demonstrated (i) a significant increase for total glucose disposal with beta-pyridylcarbinol but no significant effect of hyperglycemia and no interaction between the two treatments, and (ii) an important increase of beta-pyridylcarbinol to enhance glucose storage but no significant effect of hyperglycemia and no interaction between the two treatments. These results show that obese people, at physiological insulinemia, enhance their glucose disposal and glucose storage when lipid oxidation is artificially lowered. This suggests that enhanced lipid oxidation is related to insulin resistance in these patients. However, hyperglycemia in these patients failed to compensate for defective glucose disposal or storage.     

Impaired cortisol stress response in fish from environments polluted by PAHs,PCBs, and mercury

The cortisol stress response to capture was investigated in two species of fish (Perca flavescens and Esox lucius) from sites polluted by high levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mercury, and from reference sites in the St. Lawrence river system. Fish from the reference sites exhibited the normal elevation of serum cortisol in response to the acute stress of capture and had large pituitary corticotropes. In contrast, fish from the most polluted sites were unable to increase their serum cortisol in response to the acute stress of capture and their pituitary corticotropes were atrophied. These results suggest that a life-long exposure to chemical pollutants may lead to an exhaustion of the cortisol-producing endocrine system, possibly as a result of prolonged hyperactivity of the system.     

Effects of reperfusion intervals on skeletal muscle injury beneath and distal to a pneumatic tourniquet.

To date there have been no experimental studies specifically directed at effects of reperfusion intervals on skeletal muscle injury beneath the tourniquet. 99mTechnetium pyrophosphate (Tc 99) incorporation and correlative histology were used to assess injury 2 days after tourniquet application in muscles beneath (thigh) and distal (leg) to the cuff. Tourniquets were applied to rabbit hindlimbs for a total of either 2 or 4 hours. In the 4-hour series, tourniquet compression (either 125 mm Hg or 350 mm Hg cuff inflation pressure) was either continuous or interrupted by 10-minute reperfusion intervals after 2 hours or after every hour of cuff inflation. In the 2-hour series, tourniquet compression (350 mm Hg) was either continuous or interrupted by 10-minute reperfusion intervals after 2 hours or after every hour of cuff inflation. In the 2-hour series, tourniquet compression (350 mm Hg) was either continuous or interrupted by a 10-minute reperfusion interval after 1 hour. Pyrophosphate incorporation (Tc 99 uptake) was significantly greater in the thigh region than in the leg region in all of the 4-hour tourniquet groups. Tc 99 uptake was significantly reduced by reperfusion after each hour of cuff inflation. With 350 mm Hg tourniquet pressure, a reperfusion interval after 2 hours of cuff inflation tended to exacerbate tourniquet compression injury. Reperfusion intervals did not significantly affect Tc 99 uptake in the leg region of these groups. With a 2-hour tourniquet time, Tc 99 uptake in the thigh was significantly decreased by reperfusion after 1 hour of cuff inflation. Previous clinical recommendations, based on serum creatine phosphokinase abnormalities after experimental tourniquet ischemia, probably reflected tourniquet compression injury. Hourly reperfusion limits skeletal muscle injury during extended periods of tourniquet use.     

Endothelin-1 in children with chronic renal failure

Endothelin-1 (ET-1) was meansured after extraction from plasma of normal adults (5.9±1.9 pg/ml,n=22), normal children (7.1±1.86 pg/ml,n=29), nonhaemodialysed children with chronic renal failure (CRF) (11.1±1.8 pg/ml),n=10), renal graft recipients (9.5±3.4 pg/ml,n=37), haemodialysed children 24 h after a haemodialysis session (20.02±10.9 pg/ml,n=26) and haemodialysed children before and after a haemodialysis session (15.31±10.6 and 13.8±8.5 respectively,n=14). A sensitive and specific radioimmunoassay was used. ET-1 was significantly higher in non-haemodialysed CRF children and in renal graft recipients than in normal children (P<0.001 andP<0.01, respectively) and significantly higher in haemodialysed children when compared with normal children, non-haemodialysed CRF children and renal graft recipients (P<0.001). ET-1 concentrations were similar in normal children and normal adults. ET-1 was inversely correlated with glomerular filtration rate in non-haemodialysed CRF children (r=–0.39,P<0.01) and positively correlated with extracellular volume in haemodialysed children (r=0.435,P<0.03). After haemodialysis, ET-1 increased in 6 and decreased in 8 of the 14 children studied before and after a haemodialysis session.