Primary hyperparathyroidism in pregnancy: a diagnostic and therapeutic challenge.

The risk of severe complications arising from primary hyperparathyroidism (pHPT) is increased during pregnancy. Gestational pHPT often goes undiagnosed, and by the time it is diagnosed, a majority of women have endured one or more failed pregnancies. During pregnancy, active transport of calcium ions from the mother to the fetus leads to suppression of the fetal parathyroids. When the prenatal pool of calcium is depleted, the newborn may develop neonatal hypocalcemic tetany. The mother, in turn, may suffer from worsening hypercalcemia and a hypercalcemic crisis after delivery. Awareness and confirmation of the diagnosis may be crucial for the outcome. The only definitive treatment of pHPT is parathyroidectomy, which should be recommended in most cases. Our two cases illustrate both the importance of and the difficulty in detecting pHPT during pregnancy, as well as some of the serious complications that may occur during pregnancy and after delivery.

Complications to thyroid surgery: results as reported in a database from a multicenter audit comprising 3,660 patients.

BACKGROUND AND AIM: During recent years, more radical surgery for thyroid disease, i.e., total instead of subtotal resection, has been evident. Results following this strategy on national levels are scarce. MATERIALS AND METHODS: From 2004 to 2006, 26 Scandinavian Departments registered 3,660 thyroid operations in a database. Risk factors for complications were analyzed with multiple logistic regression. RESULTS: After thyroidectomy, re-bleeding occurred in 2.1% and was associated with older age (OR 1.04; p < 0.0001) and male gender (OR 1.90; p = 0.014). Postoperative infection occurred in 1.6% and associated with lymph node operation (OR 8.18; p < 0.0001). Postoperative unilateral paresis of the recurrent laryngeal nerve was diagnosed 3.9% and bilateral paresis in 0.2%. Unilateral paresis was associated with older age, intrathoracic goiter, thyreotoxicosis, and if routine laryngoscopy was practiced (OR 1.92; p = 0.0002). After 6 months, the incidence of nerve paresis was 0.97%. After bilateral thyroid surgery (n = 1,648), hypocalcaemia treated with vitamin D analogue occurred in 9.9% of the patients at the first follow-up and in 4.4% after 6 months. CONCLUSION: Complications to thyroid surgery are not uncommon. The high frequency of hypocalcaemia treated with vitamin D after 6 months is a cause of concern.

Operation for primary hyperparathyroidism: the new versus the old order. A randomised controlled trial of preoperative localisation.

BACKGROUND AND AIMS: In patients with primary hyperparathyroidism (PHPT), parathyroid imaging is nowadays routinely used for the purpose to perform a focused unilateral minimally invasive operation. The outcome of this new strategy has, however, not been established in randomised trials. MATERIAL AND METHODS: Patients were randomised to either preoperative localisation with sestamibi scintigraphy and ultrasonography (group I) or no preoperative localisation (group II). In group I, a minimally invasive parathyroidectomy was performed in patients in whom both localisation studies were consistent with a single pathological gland, whereas a conventional bilateral neck exploration was performed in cases with negative localisation findings. In group II all patients underwent conventional bilateral neck exploration. Primary outcome measure was normocalcaemia at 6 months postoperatively. RESULTS: In the preoperative localisation group (group I) 23/50 (46%) of the patients could be operated on with the focused operation whereas 26/50 (52%) were operated on by bilateral neck exploration. All patients in the no localisation group (group II; n = 50) were operated on with the intended bilateral neck operation. Normocalcaemia was obtained in 96% and 94% in group I and II, respectively. Total (localisation and operative) costs were 21% higher in group I. CONCLUSIONS: Routine preoperative localisation, with the intention to perform minimally invasive parathyroidectomy, is not cost effective if concordant results of scintigraphy and ultrasonography are a prerequisite for the focused operation. Less than half of the patients were successfully managed with this strategy, at a higher cost and without obtaining a more favourable clinical outcome.

Polymorphism in the coding part of the sterol 12alpha-hydroxylase gene does not explain the marked differences in the ratio of cholic acid and chenodeoxycholic acid in human bile.

OBJECTIVE: In humans, two primary bile acids are synthesized: cholic acid (CA) and chenodeoxycholic acid (CDCA), the first and rate-limiting enzyme being cholesterol 7alpha-hydroxylase (CYP7A1). CA has one more hydroxyl group at position 12alpha. This hydroxylation is carried out by the sterol 12alpha-hydroxylase (CYP8B1). Earlier, we and others have noticed a marked variation in the ratio between CA and CDCA in human bile. The aim of this study was to investigate whether this marked difference could be due to a genetic polymorphism in the gene of the CYP8B1. MATERIAL AND METHODS: Screening for genetic polymorphisms was carried out in a 2.4-kb-long area including the exon and part of the promoter region in subjects who had undergone cholecystectomy earlier, and where bile acid analysis had been performed. Among these subjects those with very high or low CA/CDCA ratios (ranging from 0.9 to 6.8) were investigated. The subjects were all female, normolipidaemic, having normal weight and a normal thyroid function. RESULTS: No polymorphisms were found in the investigated sequence. However, a statistically significant correlation was found between the activity of the CYP7A1 and the ratio between CA and CDCA. The difference in ratio could, at least in part, be explained by the difference in rate of bile acid synthesis. CONCLUSION: The difference in ratio between CA and CDCA cannot be explained by a polymorphism in the coding area of the CYP8B1.

The role of scintimammography with 99mTc-sestamibi as a complementary diagnostic technique in the detection of breast cancer.

PURPOSE: To prospectively determine the clinical value of scintimammography (Sc) with 99mTc-sestamibi as a complementary method to triple diagnosis (TD) in detecting malignant disease of the breast. MATERIAL AND METHODS: Ninety-six patients with 119 clinically or mammographically detected breast lesions underwent TD procedures, including clinical examination, mammography and fine-needle aspiration cytology. Prone planar Sc with 99mTc-sestamibi was performed in all 96 patients. Five groups were defined for diagnosis: 1=normal; 2=benign; 3=probably benign; 4=highly suspect of malignancy; and 5=malignant. All lesions were histopathologically examined. The results of each method per se and the combination of TD with Sc (TD+Sc) were analyzed. RESULTS: Histopathology of the 119 surgically excised breast lesions found 83 malignant and 36 benign lesions. TD missed 6 of 83 carcinomas, resulting in a sensitivity of 92.7%. Sc alone showed sensitivity of 85.5%. The combination TD+Sc missed 1 of 83 carcinomas, and thus had a sensitivity of 98.7%. In mammographically dense breasts both TD and Sc detected 16 of 18 carcinomas, while the combination TD+Sc led to detection of all 18 carcinomas. CONCLUSION: Adding Sc to TD increases the sensitivity for detection of breast carcinomas. Sc with 99mTc-sestamibi is recommended as a complimentary method to TD in selected cases such as mammographically dense breasts.

Postoperative nausea and vomiting after breast surgery: efficacy of prophylactic ondansetron and droperidol in a randomized placebo-controlled study.

Postoperative nausea and vomiting (PONV) is a common adverse phenomenon following breast surgery. The efficacy of ondansetron and droperidol in preventing post-operative nausea and vomiting in women undergoing breast surgery was compared in this randomized, double-blind, placebo-controlled study. Altogether 207 women were randomly assigned to receive either a single intravenous dose of droperidol (1.25 mg) (n = 69), ondansetron (8 mg) (n = 67) or saline (n = 71) immediately after induction of general anaesthesia with thiopental, fentanyl, atracurium, nitrous oxide in oxygen and isoflurane. Complaints of nausea, vomiting and requests for rescue antiemetics were recorded during a 24-h period postoperatively. During the initial 2 h in the postanaesthesia care unit, the incidence of postoperative nausea and vomiting was 15%, 6% and 12% in the placebo, droperidol and ondansetron groups, respectively (NS). The incidence of post-operative nausea and vomiting during the first 24 h was 61%, 48% and 45% in the placebo, droperidol and ondansetron treatment groups, respectively (NS). Postoperative analgesic requirements and the length of stay in the post-anaesthesia care unit were equal in all three treatment groups. It is concluded that the intravenous pretreatment with single doses of ondansetron or droperidol did not substantially prevent postoperative nausea and vomiting after breast surgery.

The level of 7-dehydrocholesterol in plasma reflects the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the human liver.

Plasma levels of the cholesterol precursor 7-dehydrocholesterol (7-DHC) were compared with activities of the rate-limiting enzyme in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase assayed in liver biopsies from patients undergoing cholecystectomy. Some patients were treated with cholestyramine, deoxycholic acid or chenodeoxycholic acid prior to surgery in order to alter the activity of the enzyme. The median level of 7-DHC and the activity of HMG-CoA reductase in the untreated group were 55 ng/ml and 98 pmol/min/mg protein, respectively. The sterol levels and enzyme activities were increased in patients treated with cholestyramine (85 ng/ml and 439 pmol/min/mg protein) and deoxycholic acid (86 ng/ml and 173 pmol/min/mg protein) and decreased in patients treated with chenodeoxycholic acid (38 ng/ml and 51 pmol/min/mg protein). There was a strong positive correlation (rs=0.75, P<0.0005) between the plasma levels of 7-DHC and the activities of hepatic HMG-CoA reductase in these patients. This correlation was further improved when the plasma levels of 7-DHC were expressed relative to those of cholesterol (rs=0.90, P<0.0001). The results show that the level of 7-DHC in plasma reflects the activity of HMG-CoA reductase in the liver.

Characterization of cytochrome P450 enzymes in human breast tissue from reduction mammaplasties.

Cytochrome P450 (CYP) enzymes in the breast may have an important role in regulating the capacity of individual cells to metabolize hormones and environmental carcinogens. Very little is known about the P450 expression pattern in human breast because of the limited amount of accessible tissue and the difficulties associated with detection of low P450 levels. Breast tissue from reduction mammaplasties is the only tissue available in relative abundance. The correlation between the P450 content in this material and P450 in breast epithelium remains to be resolved. Also questionable is the value of RT-PCR detection of P450 forms in the breast without parallel detection of the protein. In this study, we have tried to determine whether the P450 profiles in reduction mammaplasty samples reflect those in the breast epithelium and whether P450 profiles on Western blots parallel RT-PCR detection. A comparison on the level of RT-PCR was made between P450 in 15 mammaplasty samples with that in 4 ductal carcinoma samples, and 1 dissected epithelial sample. The control epithelial sample contained CYP1A1, CYP1B1, CYP2A6, CYP2B6, CYP2E1, CYP2C, CYP3A, and CYP19 (aromatase). These forms were present also in the reduction samples, with CYP2E1 and CYP1B1 being detected in all samples. In addition, the reduction samples contained CYP4A11 and CYP2D6. CYP2B6, CYP2D6, and 2C were more easily detected in the carcinoma samples, thus differing from the reduction samples and the epithelial sample. CYP was isolated from the reduction samples, and the P450 profiles on Western blots were compared with the RT-PCR results. In general, there was good agreement between the two methods, and the discrepancies found were probably caused by lack of specific antibodies. We conclude that much useful information about P450 in the breast can be obtained from reduction mammaplasty samples.

Lithogenic diet and gallstone formation in mice: integrated response of activities of regulatory enzymes in hepatic cholesterol metabolism.

Supersaturation of bile with cholesterol is a prerequisite of the development of gallstones. With the intention to study the integrated response of enzymes regulating hepatic cholesterol metabolism during gallstone formation we used an established model for the induction of cholesterol gallstone disease in mice. Ten mice were fed on a lithogenic diet containing 10 g cholesterol/kg and 5 g cholic acid/kg for 8 weeks and were compared with ten mice fed on a standard pellet diet. Cholesterol crystals or gallstones developed in 90% of gallbladders in treated mice. The lithogenic diet had an inhibitory effect on the rate-limiting enzyme of cholesterol biosynthesis, hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase (EC 1.1.1.88) activity, 39.6 (SEM 2.8) v. 171.0 (SEM 47.3) pmol/min per mg protein. Cholesterol 7 alpha-hydroxylase (EC 1.14.13.17) activity, regulating bile acid synthesis, was decreased by 80%, and this was assumed to be due to cholic acid in the diet. The cholesterol-enriched diet also induced a tenfold increase in cholesterol esterification rate in the liver, i.e. acyl-CoA:cholesterol acyl transferase (ACAT; EC 2.3.1.26) activity. The total, as well as esterified, cholesterol contents of liver homogenates were significantly higher in cholesterol- and cholic acid-treated mice and correlated well with the ACAT activity (rs 0.72 (P < 0.005), and rs 0.68 (P < 0.01) respectively). A significantly higher ACAT activity was obtained in mice given cholesterol and cholic acid even when the enzyme was saturated with exogenous cholesterol, thus indicating an increased amount of the enzyme. The formation of gallstones is dependent on a delicate balance between lithogenic factors (increased absorption of cholesterol and reduced secretion of bile acids) and defence mechanisms (decreased synthesis and increased esterification of cholesterol). In the specific animal model studied here the two defence mechanisms cannot compensate for the increased absorption of cholesterol and the reduced synthesis of bile acids.

Concentration of unsulfated lithocholic acid in portal and systemic venous plasma: evidence that lithocholic acid does not down regulate the hepatic cholesterol 7 alpha-hydroxylase activity in gallstone patients.

It has been proposed that lithocholic acid may have a physiological role for the regulation of bile acid synthesis in humans. In this study, the portal concentration and hepatic uptake of unsulfated lithocholic acid was determined in 21 gallstone patients-untreated, cholestyramine-treated and chenodeoxycholic acid-treated-at cholecystectomy. Lithocholic acid was analyzed by a combined gas-liquid mass-fragmentographic technique. In most of the patients a liver biopsy was obtained for assay of the cholesterol 7 alpha-hydroxylase activity. The portal venous concentration of unsulfated lithocholic acid averaged 0.32 mumol/l in untreated patients, constituting about 4% of the total bile acids. The apparent hepatic uptake of lithocholic acid averaged 78%, being as high as that of cholic acid. No significant correlation was obtained between the portal venous concentration of unsulfated lithocholic acid and the hepatic cholesterol 7 alpha-hydroxylase activity. This study thus confirms an enterohepatic circulation of lithocholic acid in humans. No evidence was obtained that the portal venous inflow of small amounts of lithocholic acid to the liver is of regulatory importance for the cholesterol 7 alpha-hydroxylase activity.

Influence of bezafibrate on hepatic cholesterol metabolism in gallstone patients: reduced activity of cholesterol 7 alpha-hydroxylase.

Bezafibrate is a hypolipidemic fibric acid derivative known to induce cholesterol supersaturation of bile. To characterize its effects on hepatic cholesterol metabolism, 31 normolipidemic, normal-weight patients with gallstones undergoing cholecystectomy were studied. Eleven patients (5 men) were randomized to treatment with bezafibrate, 200 mg three times daily for 4 weeks before operation; the remaining 20 patients (5 men) served as nontreatment controls. At operation, a liver biopsy specimen was obtained under standardized conditions and several important parameters of cholesterol metabolism were assayed. Bezafibrate treatment lowered total plasma cholesterol and triglycerides 30% and 37%, respectively. The hepatic cholesterol 7 alpha-hydroxylase activity was reduced by approximately 60% in the bezafibrate treated patients compared with the controls, whereas the acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity was similar in the two groups. The total 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity was increased twofold in the treated patients, whereas the active enzyme remained about the same as in the controls. The low-density lipoprotein (LDL) receptor binding activity was unaffected by the treatment. Bezafibrate treatment significantly reduces cholesterol 7 alpha-hydroxylase activity, and it is suggested that this may play an important role for the development of supersaturated bile during such therapy.

Management of splenic trauma--changing concepts.

During the last two decades the reported risk of overwhelming postsplenectomy infection (OPSI) has resulted in a conservative approach to splenic trauma, with the aim of splenic salvage. The appropriateness of this strategy is now questioned. The risk of OPSI varies with age and indication for splenectomy from less than 1% in adults to more than 4% in children. Pneumococcus is the causative agent in about 60% of cases. A prerequisite for splenic preservation procedures should be a haemodynamically stable patient without other intraabdominal injuries. The benefits derived from non-operative treatment of splenic salvage procedures may be overshadowed by the potential risk of transfusion-related bacterial and viral diseases. Polyvalent pneumococcal vaccines given early after splenectomy appear to reduce the incidence of OPSI substantially.

12 alpha-hydroxylase activity in human liver and its relation to cholesterol 7 alpha-hydroxylase activity.

Interruption of the enterohepatic circulation by cholestyramine causes a several-fold increase in bile acid synthesis, reflected in a stimulation of cholesterol 7 alpha-hydroxylase activity; the synthesis of cholic acid being stimulated to a greater extent than chenodeoxycholic acid. It is not known if this preferential increase in cholic acid is due to an increase of the 12 alpha-hydroxylase activity. The present study aimed at investigating the 12 alpha-hydroxylase activity and its relation to cholesterol 7 alpha-hydroxylase activity in liver microsomes of patients with different levels of cholesterol 7 alpha-hydroxylase activity. Liver biopsies were obtained from four gallstone-free patients, and seven untreated and two cholestyramine-treated gallstone patients undergoing cholecystectomy, and four patients with Crohn's disease undergoing intestinal resection. The combined group of cholestyramine-treated and ileum-resected patients had four times higher cholesterol 7 alpha-hydroxylase activity and two times higher 12 alpha-hydroxylase activity than the other patients. A positive correlation was obtained between cholesterol 7 alpha-hydroxylase activity and 12 alpha-hydroxylase activity (r = +0.69; n = 16). These results indicate that the increased ratio between the synthesis of cholic acid and chenodeoxycholic acid during cholestyramine treatment is due to a compensatory increase of the 12 alpha-hydroxylase activity.

Hepatic cholesterol metabolism in estrogen-treated men.

Operative liver biopsies were obtained from two male patients who developed gallstone disease during estrogen treatment of metastatic prostatic carcinoma. The heparin-sensitive binding of 125I-low-density lipoprotein (LDL) to liver homogenates (reflecting the expression of the LDL receptor) was determined, together with the activities of the rate-limiting enzymes in cholesterol synthesis [3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase], bile acid production (cholesterol 7 alpha-hydroxylase), and cholesterol esterification (acyl CoA:cholesterol acyl transferase). The results were related to data available in 18 patients (5 male, 13 female) who underwent cholecystectomy because of gallstone disease. The hepatic 125I-LDL-binding activity was increased threefold compared with five controls, and the activity of HMG-CoA reductase was increased twofold. There was no major difference in the activities of cholesterol 7 alpha-hydroxylase or acyl CoA:cholesterol acyl transferase. The concentration of free and total cholesterol in liver microsomes was approximately 30% lower in the estrogen-treated men than in 11 controls. The results indicate that estrogen at pharmacological doses stimulates hepatic LDL-receptor expression and HMG-CoA reductase activity in men. The increased LDL-receptor expression could in part explain the enhanced plasma clearance of injected 125I-LDL and hence the reduction in plasma LDL cholesterol previously shown to occur in estrogen-treated men.

Cholesterol metabolism in human gallbladder mucosa: relationship to cholesterol gallstone disease and effects of chenodeoxycholic acid and ursodeoxycholic acid treatment.

The objective of this study was to investigate cholesterol metabolism in human gallbladder mucosa, especially in relation to hepatic cholesterol metabolism, gallstone disease and treatment with bile acids. Gallbladder mucosa and liver tissue samples were collected in 44 patients undergoing cholecystectomy; 30 had cholesterol gallstones and the rest were stone free. Ten of the gallstone patients were treated with chenodeoxycholic acid and eight received ursodeoxycholic acid, with a daily dose of 15 mg/kg body wt, for 3 wk before surgery. The 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, governing cholesterol synthesis, was considerably lower in the gallbladder mucosa than in liver tissue (28 +/- 6 and 120 +/- 40 pmol/min/mg protein). The acyl coenzyme A:acyltransferase activity in the gallbladder mucosa catalyzing the esterification of cholesterol was, on the other hand, several times higher than corresponding activity in the liver (92 +/- 23 and 11 +/- 2 pmol/min/mg protein). In the presence of exogenous cholesterol, the acyl coenzyme A:acyltransferase activity increased about twofold in the gallbladder mucosa. The acyl coenzyme A:acyltransferase activity of the gallbladder mucosa from untreated gallstone patients was not stimulated further by the addition of exogenous cholesterol. Otherwise, there were no significant differences in acyl coenzyme A:acyltransferase and 3-hydroxy-3-methylglutaryl coenzyme A reductase activities in the gallbladder mucosa of gallstone patients compared with gallstone-free controls. Treatment with chenodeoxycholic and ursodeoxycholic acids did not affect the 3-hydroxy-3-methylglutaryl coenzyme A reductase activity of the gallbladder mucosa but reduced the acyl coenzyme A:acyltransferase activity by 60% to 65%.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of growth hormone for the induction of hepatic low density lipoprotein receptors.

This investigation was undertaken to determine the possible role of growth hormone (GH) in the hormonal regulation of hepatic low density lipoprotein (LDL) receptor expression. Treatment of normal rats with estrogen (ethynylestradiol, 5 mg/kg per day) increased the number of hepatic LDL receptors, and the LDL receptor mRNA levels were increased 2.4-fold. However, when hypophysectomized rats were treated with estrogen, the hepatic LDL receptor number and the mRNA levels only increased slightly. Treatment with GH was important to restore the induction of hepatic LDL receptors in hypophysectomized estrogen-treated rats. Further, the hypocholesterolemic effect of estrogen was abolished in hypophysectomized rats, and GH reversed this effect. To assess the effect of GH in humans, hepatic LDL receptor binding activity was determined in liver biopsy specimens from gallstone patients pretreated with GH (12 international units/day) prior to operation. GH administration induced hepatic LDL receptors approximately 2-fold, and this was accompanied by a 25% decrease in serum cholesterol. The LDL receptor stimulation caused by GH treatment was of similar magnitude as that observed upon 3 weeks of treatment with an established hypolipidemic drug (pravastatin or simvastatin). The data show that GH has an important role in the regulation of hepatic LDL receptors and suggest that GH secretion may be important for the control of plasma LDL levels in humans.

Nucleation time of gall bladder bile in gall stone patients: influence of bile acid treatment.

The time required for precipitation of cholesterol crystals (nucleation time, NT) was determined and related to the cholesterol saturation in gall bladder bile of gall stone free subjects (n = 11), patients with pigment stones (n = 3), and patients with cholesterol gall stones (n = 30) undergoing cholecystectomy. Seven of the gall stone patients had been treated with chenodeoxycholic acid (CDCA) and nine with ursodeoxycholic acid (UDCA), 15 mg/kg/day for three weeks before operation. NT was longer in gall stone free subjects (mean, 20 days), patients with pigment stones (14 days) and patients treated with CDCA (24 days) and UDCA (17 days) compared with untreated patients with cholesterol gall stones (1.5 days). In spite of low cholesterol saturation and prolonged NT, and in contrast to those treated with CDCA, four of the nine patients treated with UDCA had cholesterol crystals in their bile. These observations give further support to the concept that the mechanism for inducing gall stone dissolution may be different for CDCA and UDCA.

Interruption of the enterohepatic circulation of bile acids stimulates the esterification rate of cholesterol in human liver.

The activity of acyl CoA: cholesterol acyltransferase (ACAT), which catalyzes the esterification of cholesterol, was studied in liver microsomes obtained from cholestyramine-treated gallstone patients (n = 12) and patients with Crohn's disease who had undergone partial ileal resection (n = 11). Gallstone patients (n = 33) and gallstone-free subjects undergoing cholecystectomy because of polyps of the gallbladder (n = 8) served as controls. The mean levels of the ACAT activity were the same in the gallstone and the gallstone-free patient groups (6.0 +/- 0.4 and 6.1 +/- 1.1 pmol/min per mg protein, respectively). When exogenous cholesterol was added to the assay system the activities were increased four- to fivefold in both groups. The ACAT activity tended to be increased in the cholestyramine-treated patients (8.1 +/- 1.8 pmol/min per mg protein), and was significantly enhanced (P less than 0.005) in the ileal-resected patients (12.3 +/- 2.3 pmol/min per mg protein). When the enzyme activity was determined with added exogenous cholesterol, it was significantly higher compared to the controls in both the cholestyramine-treated patients and the patients with ileal resection (57.9 +/- 11.6 and 50.0 +/- 10.3 pmol/min per mg protein, respectively). The content of free and esterified cholesterol in liver homogenates and microsomes was not significantly different between the patient groups. We conclude that ACAT activity is increased in patients with interruption of the enterohepatic circulation of bile acids, and speculate that this reflects a stimulated uptake of lipoprotein cholesterol and may indicate that more cholesteryl esters are incorporated into very low density lipoproteins.

Effects of pravastatin and cholestyramine on products of the mevalonate pathway in familial hypercholesterolemia.

Patients with heterozygous familial hypercholesterolemia (n = 12) were treated either with pravastatin, a specific inhibitor of HMG-CoA reductase, or cholestyramine, followed by a period of combined treatment with both drugs. Initially, these patients had increased serum levels of low density lipoprotein (LDL) cholesterol (8.77 +/- 0.48 mmol/l; SEM), lathosterol (5.32 +/- 0.60 mg/l), and ubiquinone (0.76 +/- 0.09 mg/l), while the serum dolichol concentration was in the normal range. Cholestyramine treatment (n = 6) decreased the levels of LDL cholesterol (-32%) and increased lathosterol (+125%), but did not change dolichol or ubiquinone levels in a significant manner. Pravastatin treatment (n = 6) decreased LDL cholesterol (-27%), lathosterol (-46%), and ubiquinone (-29%). In this case, the amount of dolichol in serum also showed a small but statistically insignificant decrease (-16%) after 12 weeks of treatment. Combined treatment with cholestyramine and pravastatin (n = 6) resulted in changes that were similar to, but less pronounced than, those observed during pravastatin treatment alone. In no case was the ratio between ubiquinone and LDL cholesterol reduced. Possible effects on hepatic cholesterol, ubiquinone, and dolichol concentrations were studied in untreated (n = 2), cholestyramine-treated (n = 2), and pravastatin-treated (n = 4) gallstone patients and no consistent changes could be observed. The results indicate that treatment with pravastatin in familial hypercholesterolemia decreases serum ubiquinone levels in proportion to the reduction in LDL cholesterol.