We inserted the 0.6 mm caliber graft-heparin (in inner wall) conduits into the tailarteries of 14 mice. The results showed that the graft conduit could be used repeatedly with no blood oozing out in the wound, no massive internal hemorrhage, and no additional coagulative reagent given during the whole experiment. On the other hand, the graft-heparin conduits of variant caliber were inserted into the femur arteries of 4 rabbits and 4 dogs for blood pressure experiment and femur arterio-venous bypass tests. The results showed that the anticoagulative effect of these conduits was markedly improved, but there was a strip of thrombus. There was no thrombus track in the wall of the conduit. The strip of thrombus was formed first in the cone of conduit where caliber changed. The results indicate that the blood flow resistance is in inverse proportion to 4 power of the conduit radius. So the thinner the conduit is, the more sensitive to conduit radius variation the conduit resistance will be. In studying and making the arfificial conduit, one must take notice of the conduit caliber, which should be equal to the caliber of the blood vessel.
Animals ; Anticoagulants ; administration & dosage ; Blood Vessel Prosthesis ; Dogs ; Heparin ; administration & dosage ; Mice ; Rabbits ; Regional Blood Flow

OBJECTIVETo investigate the relationship between blood pressure variability, overweight or obesity in patients with essential hypertensive.

METHODSA hundred ninety-one patients with essential hypertension were divided into three groups: normal, overweight and obese according to body mass index (BMI). The characteristics of the variability of 24-hour ambulatory blood pressure monitoring (ABPM) in three groups were compared.

RESULTSBlood pressure overload and variability increased parallel with the increase of BMI. In overweight group, the variabilities of systolic blood pressure at night (nSBPSD) increased 14.10%, the variabilities of diastolic blood pressure at night (nDBPSD) increased 13.15% and the variabilities of mean arterial pressure at night (nMAPSD) increased 15.92% respectively. In the obese group, the above three variabilities increased more significantly (compared to normal group P < 0.05-0.01). However, increases of the three blood pressure variabilities were observed only in the male patients.

CONCLUSIONSThe overweight or obesity increased the blood pressure overload and variabilities in patients with essential hypertension. The increases of blood pressure variabilities were observed only in male patients and at night.

Adult ; Aged ; Blood Pressure ; Body Mass Index ; Female ; Humans ; Hypertension ; physiopathology ; Male ; Middle Aged ; Obesity ; physiopathology ; Sex Factors

OBJECTIVETo study the contribution of genetic factors to the variance of serum leptin concentration in healthy, normotensive twins.

METHODSA total of 57 pairs of twins were investigated: 28 female and 19 male pairs of monozygotic(MZ) twins, and 6 female and 4 male pairs of dizygotic(DZ) twins. The zygosity of twins was determined by comparing the concordance of the genotype of nine fluorescence-labeled microsatellite markers. The genetic analysis was performed using the variance-based method. Serum leptin levels were determined in duplicate by a radioimmunoassay Kit (Linco Research, Inc., St. Charles, Missouri) as previously described.

RESULTSThe test of genetic variance revealed a significantly larger within-pair variance of serum leptin in the DZ twins, in comparison with the MZ twins. The corresponding heritability for serum leptin was 8%. Adjusted for BMI, gender, and uric acid (UA), the heritability for serum leptin was 0.18%. Log leptin correlated significantly with blood pressure (SBp r=0.355 P<0.001; DBp r=0.339 P<0.001). Stepwise multiple linear regression analysis revealed that only BMI, gender and UA were linked independently to serum leptin levels(R(2)=0.788, P<0.001).

CONCLUSIONThe above data indicate that environmental factors other than genetic factors are important determinants of leptinemia in normal subjects.

Adolescent ; Adult ; Body Mass Index ; Female ; Genotype ; Humans ; Leptin ; blood ; genetics ; Male ; Microsatellite Repeats ; genetics ; Middle Aged ; Twins, Dizygotic ; genetics ; Twins, Monozygotic ; genetics