The effect of neck dissection on human fat transport.

This study examines the effect of neck dissection and thoracic duct ligation on lipid metabolism. Included were 23 patients undergoing neck dissection with thoracic duct ligation. The results showed a temporary reduction in lipid metabolism in approximately half the patients who had a left neck dissection. This effect subsided within 6 months, possibly because of the development of alternative lymph channels. The reduction in fat metabolism in selected cases may have therapeutic effects on patients with morbid hypertriglyceridemia or those who receive chemopreventive regimens. To the best of our knowledge, no similar studies have been reported heretofore in humans.

Susceptibility of serum lipids to copper-induced peroxidation correlates with the level of high density lipoprotein cholesterol.

As a first step in evaluating the significance of our recently developed method of monitoring the kinetics of copper-induced oxidation in unfractionated serum, we recorded the kinetics of lipid oxidation in the sera of 62 hyperlipidemic patients and analyzed the correlation between oxidation and lipid composition of the sera [high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides]. We used six factors to characterize the kinetics of oxidation, namely, the maximal absorbance of oxidation products (ODmax), the maximal rate of their production (Vmax), and the time at which the rate was maximal (t(max)) at two wavelengths (245 nm, where 7-ketocholesterol and conjugated dienic hydroperoxides absorb intensely, and 268 nm, where the absorbance is mostly due to dienals). The major conclusions of our analyses are that: (i) Both ODmax and Vmax correlate positively with the sum of concentrations of the major oxidizable lipids, cholesterol, and cholesteryl esters. (ii). The value of t(max), which is a measure of the lag preceding oxidation and therefore reflects the resistance of the serum lipids to copper-induced oxidation, exhibits a negative correlation with HDL cholesterol. Although this finding accords with the observation of shorter lags for HDL than for LDL, it is apparently inconsistent with the role of HDL as an antirisk factor in coronary heart diseases.

The influence of thyroid function on serum lipid profile.

Serum triglycerides, cholesterol, HDL-C and LDL-C levels as well as the LDL/HDL cholesterol ratio were determined in 11 patients suffering from hyperthyroidism and 7 patients suffering from hypothyroidism, and compared with those of 19 sex-and age-matched controls. In hypothyroidism a net increase of all lipid values was observed. In hyperthyroidism cholesterol and LDL-C values were reduced while those of the triglycerides and HDL-C were unchanged as compared with controls. The LDL/HDL cholesterol ratio in either group of patients was lower than in controls, the lowest being observed in thyrotoxicosis.