Serum lipid and lipoprotein profiles in childhood

Serum lipids and lipoproteins as well as other factors have been shown to be predictive of future symptomatic coronary heart disease in adult populations. Many epidemiologic data are available on serum lipids in adults in different populations; similar data in children indicate a large geographic variability between different populations and even among individuals of the same population, suggesting that both genetic and environmental factors are determinants of serum lipid concentrations. Serum cholesterol at birth and during childhood is carried predominantly by low-density lipoprotein (LDL) and high-density lipoprotein (HDL) whereas very low-density lipoprotein (VLDL) remains very low during the same period. Longitudinal studies show that serum cholesterol level decreases slightly with age in boys but not in girls; the decreasing trend is most evident between 10 and 14 years of age. LDL cholesterol follows the same trend. A continuous slight increase in serum total and VLDL triglyceride has been shown with age. HDL cholesterol seems to maintain a constant level with only slight variation with age. Moreover, LDL cholesterol has great consistency with future levels. Measurements made in children confirm that high levels of cholesterol may be present at early ages, suggesting the need for follow-up studies in young populations in order to evaluate whether hypercholesterolemia in childhood is predictive of future coronary events.

[Report of a clinical case of tuberculous L/S spondylitis with radiologic and C.T. documentation]

A case of tuberculous spondylitis is presented and various aspects of its diagnosis are discussed. Stress is laid on the importance of radiology and CT in the diagnosis of this disease, and the monitoring of its progress.

Increased blood flow to lower limbs after plasma exchange in two patients with familial hypercholesterolemia

Leg blood flow was measured before and 1 and 7 days after plasma exchange by venous occlusion plethysmography in a 9-year-old girl with homozygous familial hypercholesterolemia and in a 41-year-old man with heterozygous familial hypercholesterolemia. In the first patient the plasma cholesterol level was reduced from 890 mg/dl to 532 mg/dl and 666 mg/dl 1 and 7 days after plasma exchange. In the second patient plasma cholesterol decreased from 596 mg/dl to 342 mg/dl and 480 mg/dl, respectively. Leg arterial flow increased from 8.5 ml/min/l of leg volume to 19.1 and 19.5 ml/min/l in the first patient and from 6.6 ml/min/l to 18.0 and 21.8 ml/min/l in the second. No change was observed in haematocrit and total globulin concentration, which are known to play an important role in blood viscosity and flow. It is concluded that plasma exchange, possibly by decreasing plasma cholesterol concentration in patients with familial hypercholesterolemia, is associated with improved arterial flow to lower limbs and it is suggested therefore that some beneficial effect might be found also in other vascular beds.

Nitrogen loss and urinary creatinine excretion during fasting in massive obesity

Six (5 f, 1 m) massively obese, otherwise healthy subjects, were submitted for 4 weeks to a very-low-calorie diet (VLCD): 80 kcal, 335 kJ = 2.6 g N/day (17 g protein, 0 CHO and fat). Daily urinary creatinine excretion (UCE) and weekly nitrogen loss (NL) were determined during the whole period of treatment. Both NL and UCE decreased from the second week of treatment indicating a progressive sparing effect on lean body mass (LBM). A positive correlation (r = 0.991, P less than 0.001) was observed between mean daily UCE and NL, indicating that NL during prolonged fasting in obesity is possibly influenced by the lean body mass of the individual.

Obesity and cardiac function

We studied 10 obese volunteers, mean age 36.5 +/- 10.3 years, who weighed 123.56 +/- 28.7 g and were 69.96 +/- 22.5 kg overweight. The subjects did not have diabetes, arterial hypertension or signs of cardiac and respiratory failure or disease and all underwent right- and left-heart catheterization. cardiac output and stroke volume were high, according to increased oxygen consumption and to the degree of obesity. Ventricular end-diastolic and atrial pressures ranged from normal to high and correlated with body weight, signs of volume overloading and reduced left ventricular (LV) compliance. The mean pulmonary artery pressure was elevated and correlated well with weight, pulmonary resistance being normal; mean aortic pressure did not correlate with weight, and systemic arterial resistance tended to have a negative correlation. The LV function curve showed impaired ventricular function, particularly for the heaviest subjects, in whom Vmax and the ratio of the stroke work index to LV end-diastolic pressure were reduced. These indexes correlated well with each other and both correlated negatively with the degree of obesity. In contrast, maximal dP/dt was normal and did not correlate with excess weight. These observations show that depressed LV function is already present in relatively young obese people, even if they are free from signs of cardiopathy and other associate diseases. The degree of impairment of heart function seems to parallel the degree of obesity.

Analytical fractionation of human liver microsomal fractions: localization of cholesterol and of the enzymes relevant to its metabolism

1. The submicrosomal distribution of three enzymes concerned in cholesterol metabolism, and of free and esterified cholesterol, was determined in human liver by analytical isopycnic centrifugation on sucrose gradients. 2. The distribution profile and median density of acyl-CoA:cholesterol O-acyltransferase was similar to that of RNA, showing that this enzyme is confined largely to the ribosome-rich membranes of the endoplasmic reticulum. The distribution profiles and median densities of 3-hydroxy-3-methylglutaryl-CoA reductase and cholesterol 7 alpha-mono-oxygenase showed that both enzymes are confined to the smooth, ribosome-poor, endoplasmic reticulum. 3. Most of the free cholesterol in the microsomal preparations was present in smooth membranes from the Golgi apparatus and in vesicles from plasma-membrane fragments. The distribution of esterified cholesterol was multimodal and extended throughout the whole gradient.

Evaluation of the safety of very-low-calorie diets in the treatment of severely obese patients in a metabolic ward

Nitrogen balance has been measured in 25 (18 f, 7m) obese non-diabetic patients submitted for four weeks to different versions of very-low-calorie diets (VLCD). Patients were divided into four groups and treated as follows: Gp 1 (6f, 4m) by 80 kcal (0.34 MJ) VLCD (17 g protein [= 2.6 g N], tr CHO and fat); Gp 2 (4f, 1m) by 180 kcal (0.76 MJ) VLCD (40 g protein [= 6.4 g N], 2 fat, tr CHO); Gp 3 (4f, 1m) by 80/180 kcal (0.34/0.76 MJ) VLCD (80 kcal during the 1st and 2nd week and 180 kcal during the 3rd and 4th week with the same nutrients as Gps and 1 and 2, respectively). Gps 1-3 received VLCD which essentially contained only protein. Gp 4 (4f, 1m) was treated by a 'mixed' VLCD containing protein and CHO (80 kcal, as in Gp 1 during the 1st and 2nd week; and 180 kcal, 17 g protein + 25.5 g CHO during the 3rd and 4th week of treatment). Weight loss was similar in Gps 1, 3 and 4 (-11 kg) and lower (-8 kg) in Gp 3. Mean daily nitrogen loss was lower in Gp 2 and 3 (-3.2 and -2.9 g N/day respectively). From the 3rd week of treatment nitrogen loss was reduced in Gps 1 and 2 and virtually absent in Gp 3. In Gp 4 nitrogen loss was persistently high (4.3-5.8 g N/day) during the whole period of observation.

IN CONCLUSION

at a very low energy intake of below 200 kcal (0.84 MJ)/day dietary substitution of protein with carbohydrates does not ameliorate the nitrogen balance.

Plasma high density lipoprotein in severe obesity after stable weight loss

Changes in plasma lipoprotein pattern, with particular attention to high density lipoprotein cholesterol (HDL-C) concentration, were evaluated in 7 (5 female, 2 male) obese patients before and 15 +/- 1 months after they had lost weight (mean 20.7 +/- 3.1 kg), when the patients' food intake had been ad libitum for at least 6 months, and they had been maintaining their weight loss. Plasma low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein triglyceride (VLDL-TG) concentrations were lower than baseline values: on the other hand, plasma HDL-C concentration, which was below normal values before weight reduction, was found to be significantly increased (P < 0.05). These data indicate that, among the favourable changes in plasma lipoprotein pattern, an increase in HDL-C may be achieved after remarkable and stable weight loss in severe obesity.

Effect of dietary fibre on glucose control and serum lipoproteins in diabetic patients

To evaluate the effects of a fibre-rich diet on blood glucose and serum lipoproteins, eight diabetic patients, four on insulin and four on oral hypoglycaemic drugs, were put on three different diets, a different one for each consecutive 10-day period: diet A (carbohydrate 53%, fibre 16 g), diet B (carbohydrate 53%, fibre 54 g), and diet C (carbohydrate 42%, fibre 20 g). All diets had identical polyunsaturated/saturated fat ratios. Both 2 h post-prandial glucose and mean daily glucose levels were significantly lower after diet B than after either of the two other diets, as were total and LDL cholesterol levels. Total and VLDL triglyceride levels after diet B were significantly lower than those after diet A but almost identical to those after diet C. HDL cholesterol concentration was not affected by dietary fibre but was significantly increased by the low-carbohydrate diet. A high-fibre, normal-carbohydrate diet (the fibre coming exclusively from foodstuffs with a naturally high content of fibre) improves blood glucose control and decreases the concentration of atherogenic lipoproteins in diabetic patients. This effect is independent of the amount of available carbohydrates in the diet.

Plasma lipoproteins in maturity onset diabetes

Plasma lipoprotein abnormalities in maturity onset diabetes (MOD) reflect both enhanced production and impaired removal of triglyceride-rich lipoproteins. Hyperglycemia and hyperinsulinemia lead to overproduction of very-low density lipoproteins by the liver. Fat tolerance is reduced in MOD patients: this might be due to low lipoprotein lipase activity (LLA) and/or to low incorporation of LLA-released fatty acids into adipose tissue glyceride. This finding of abnormal low-density lipoprotein composition, with relative enrichment in triglyceride, suggests remnant particle accumulation.

Protein-sparing modified fast in the treatment of severe obesity: weight loss and nitrogen balance data

Nitrogen balance has been measured in 25 (16 f, 9m) patients with severe obesity submitted for four weeks to total fasting (TF) or different versions of protein-sparing modified fast (PSMF). The hospitalized patients, divided into four age-matched groups, were treated as follows:Group 1, were submitted to TF; Group 2 were treated by 80 kcal-PSMF (17 g protein=2.6 g N, traces of fat and carbohydrate); Group 3 were submitted to 180 kcal-PSMF (40 g protein = 6.4 g N, 2 g fat, traces carbohydrate) and Group IV, to 80/180 kcal-PSMF (80 kcal during the 1st and 2nd week and 180 kcal during the 3rd and 4th week of treatment). Weight loss was similar (-11 kg) in Gps 1, 2 and 4; lower (-8 kg) in Gp 3. Mean daily Nitrogen loss was significantly lower (P < 0.05) in Gps 3 and 4 than in Gps 1 and 2. Nitrogen loss was significantly reduced from the 3rd week onward in Gps 1 (P < 0.005), 2 (P < 0.05) and 4 (P < 0.002). During 180 kcal-PSMF nitrogen loss was significantly lower (P < 0.005) only when this dietary regimen was preceded by 80 kcal-PSMF for two weeks (Gp 4). These observations suggest a new approach to the treatment of severe obesity by PSMF and show that is is possible to further reduce the early catabolic phase which commonly arises during this type of therapy.

Left arm thermography in early and maturity onset obesity

Left-arm thermography and adipose-tissue biopsy of triceps skinfold have been performed in seven patients with obesity of early onset (EO), seven with maturity-onset obesity (MO) and seven non-obese control subjects (C). Obese patients were within the same range for age, physical activity, excess body-fat content and skinfold thickness; mean fat-cell diameter was found to be significantly higher in the group MO than either EO (P less than 0.05) or C subjects (P less than 0.01). Colour thermograms, as evaluated by a well-standardized score system, showed that skin temperature was higher in MO than in EO or C cases (P less than 0.05). The combination of fat-cell hyperplasia and lower thermal losses from the skin, indicative of a lower rate of energy expenditure, may explain the higher frequency of therapeutically refractory cases in EO than MO patients.

Acyl-coenzyme A--cholesterol acyltransferase activity in human liver

1. In the presence of CoA and ATP, human liver microsomes catalyse the incorporation of [14C]oleate or [14C]cholesterol into cholesteryl oleate, thus demonstrating the presence of acyl-coenzyme A-cholesterol acyltransferase (cholesterol acyltransferase) in human liver. 2. The enzyme has properties similar to those of rat liver enzyme and with both the concentration of endogenous cholesterol in the microsomal fraction is adequate to support a constant initial rate of esterification. However, unlike the rat liver enzyme, the human cholesterol acyltransferase does not efficiently utilize added cholesterol as substrate. 3. The activity of cholesterol acyltransferase in human liver was 25% of that measured in rat liver under similar conditions of assay.

Blood lipids in Italy. Regional differences

Serum cholesterol and triglyceride levels have been evaluated in samples from fasting males aged 20--59 in Northern (Brisighella), Central (Rome) and Southern (Pozzuoli) Italy. Regularly performed quality controls between laboratories assured comparability of data. A statisitically significant difference of mean serum cholesterol and triglyceride levels was observed for most age-groups in the 3 different areas, lower values being found in the southern population as compared to the central and northern ones. These results support previous findings and the thesis that large differences in blood lipid levels may still exist even within the same country and that they at least in part may be culturally determined in connection with different dietary habits.

Feedback regulation of metabolism by dietary constituents: lipids

Cholesterol is distributed in different body pools, Input in these pools takes place through absorption of dietary cholesterol and endogenous synthesis. Absorption is limited in man. Endogenous synthesis is under negative feedback control, but its physiological relevance in man is less well established. Recent studies in familial hypercholesterolemia have shown a slower catabolism of low density lipoproteins (LDL) and an overproduction of apoprotein B. It seems that also the synthesis of the apoprotein B is controlled by a feedback mechanism. Overall concentration of lipids and lipoproteins in plasma is determined by the interaction between several genetic and dietary feedback mechanisms.

Turnover of cholesteryl esters in plasma low-density and high-density lipoproteins in familial hyperbetalipoproteinaemia

1. The turnover of cholesteryl esters in plasma high-density (HDL) and low-density (LDL) lipoproteins was measured in patients with familial hyperbetalipoproteinaemia in the homozygous and heterozygous forms and in control subjects.

2. The fractional rates of turnover of HDL and LDL cholesteryl esters were significantly lower in the patients than in the control subjects, but there was no significant difference between the absolute rates of turnover (expressed in mg h−1 kg body wt.−1) in the patients and controls.