Purification of rat liver lysosomal cholesteryl ester hydrolase.

An acidic cholesteryl ester hydrolase (EC 3.1.1.13) from rat liver lysosomes was purified approximately 120-fold with 5% recovery of the original homogenate activity. The sequential steps were: digitonin solubilization, agarose gel filtration, DEAE-agarose and CM-agarose column chromatography. The enzyme was at least 90% pure as judged by polyacrylamide gel electrophoresis and sodium dodecyl sulfate polyacrylamide gel electrophoresis. It exhibited a molecular weight of about 60 000 as determined by sodium dodecyl sulfate polyacrylamide electrophoresis and gel filtration. The soluble enzyme required substrate which was incorporated into phospholipid vehicles for optimal activity. On the contrary, aggregates of the enzyme required a substrate preparation that involved the direct addition of cholesteryl ester in acetone. The enzyme also catalyzed the hydrolysis of emulsions of triacylglycerol. The ratio of the two activities remained almost constant during purification suggesting that the two activities (EC 3.1.1.13 and EC 3.1.1.3, respectively) may be the result of the broad specificity of one enzyme. The effects of some inhibitors and some properties of the enzyme have been studied and discussed.

In vitro incorporation of isomeric cis-octadecenoic acids by rat liver mitochondria.

The metabolic fate of positional isomers of cis-octadecenoic acids was compared to that of oleic acid, elaidic acid and stearic acid in rat liver mitochondria. The positional isomers as well as elaidic acid and stearic acid were labelled with 3H and they were incubated in pairs with [1-14C]oleic acid. 3H/14C ratios were determined for the administered mixtures and for the isolated lipid classes. The results suggested that all isomers were readily incorporated into the membraneous structure of mitochondria. Those with the double bond in the middle of the acyl chain resembled oleic acid and they were preferentially incorporated in cholesterol esters, triacylglycerols and in the 2-position of triacylglycerols and of phosphatidylcholines. Those with the double bond away from the middle of the chain were metabolically distinct from oleic acid and behaved like trans fatty acids. They were rapidly taken up by mitochondria. They were preferentially incorporated in phospholipids and they occupied the 1-position in phosphatidylcholines and the 1- and 3-positions in triacylglycerols.

Reversible impairment of gonadotropin secretion in critical illness. Observations in postmenopausal women.

Gonadotropin levels were measured in 65 postmenopausal women admitted to the intensive care unit. Sixteen patients (25%) were hypogonadotropic as measured by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels of 5 IU/L or less, and only 20 patients (31%) were found to have gonadotropin levels within the expected postmenopausal range (greater than or equal to 30 IU/L). No significant differences in prolactin or free thyroxine levels were found, but the cortisol level was higher and the total thyroxine level lower in the hypogonadotropic group. The patients in the hypogonadotropic group also seemed more seriously ill, with a longer duration of hospitalization, an increased total number of days in the intensive care unit, an increased number of days in the intensive care unit before gonadotropin sampling, a higher incidence of parenteral hyperalimentation, lower serum albumin levels, and higher mortality. Stimulation of the gonadotropin-releasing hormone performed on 10 patients showed a blunted response in patients with baseline LH and FSH levels of 10 IU/L or less. Of 10 patients followed up sequentially, 6 showed a rise in gonadotropin levels that paralleled recovery, 1 died with low gonadotropin levels, and 3 continued to have low gonadotropin levels 17, 34, and 82 days, respectively, after initial screening. Critically ill postmenopausal women may exhibit a marked fall in gonadotropin, LH, and FSH levels. This disease in gonadotropin levels in response to illness is reversible and results from pituitary unresponsiveness to gonadorelin hydrochloride.

Inhibition of pituitary gonadotropin secretion by 4-aminopyrazolo(3,4-d) pyrimidine.

The reduction of plasma testosterone (T) in male rats treated with 4-aminopyrazolo(3,4-d)pyrimidine (4-APP) has been recently shown to be associated with a fall in plasma LH, and appears to be secondary to this impairment of gonadotropin secretion rather than to the decrease in lipoprotein cholesterol caused by the adenine analog. The effects of 4-APP on pituitary function and the mechanism of the fall in gonadotropin secretion were analyzed in adult male rats treated ip with 5, 10, 25, and 50 mg 4-APP/kg BW for 3 days. Twenty four hours later, serum cholesterol levels were reduced by 68 +/- 5% (mean +/- SE) in animals treated with 5 mg 4-APP/kg BW and by up to 84 +/- 1% after higher doses. Basal levels of serum T were not affected by 5 mg/kg APP but were significantly reduced by higher doses (P less than 0.05). Serum T responses to human CG (100 IU) stimulation in APP-treated rats were reduced in absolute magnitude, but were enhanced in terms of percentage increase above baseline. The three highest doses of 4-APP reduced serum levels of LH (51-79%) and FSH (21-39%). However, serum gonadotropin responses to GnRH stimulation were augmented by 32 +/- 9% for LH and 27 +/- 12% for FSH after 4-APP treatment. Serum levels of TSH were significantly (P less than 0.05) reduced by 25 and 50 mg/kg 4-APP and serum PRL was lowered by only the higher dose. Serum GH was lowered and ACTH increased by 5 mg/kg 4-APP. The pituitary contents of LH, FSH, and TSH were unchanged after 4-APP treatment, but PRL and GH contents were slightly but significantly increased (P less than 0.05). Pituitary receptors for GnRH (88 +/- 14 fmol/mg protein) were reduced by in vivo treatment with 25 and 50 mg/kg 4-APP to 52 +/- 5 and 57 +/- 7 fmol/mg, but not by 10 mg/kg 4-APP. No change in pituitary GnRH receptor content was observed after 48-h exposure to 10(-7) or to 10(-5) M 4-APP in vitro. The medial hypothalamic GnRH content was unchanged by 4-APP treatment. The dissociated effects of 4-APP on serum cholesterol and T levels, and the maintenance of T responses to human CG, provide further evidence that testicular androgen biosynthesis is not solely dependent on circulating cholesterol. The greater sensitivity of pituitary gonadotropins to 4-APP inhibition is evidence for a selective action of this drug on pituitary hormone release in vivo. Although the hypothalamic content of GnRH was unaltered by 4-APP treatment, the decrease in pituitary GnRH receptors observed in vivo, together with the fall in circulating LH and FSH and retention of gonadotropin responses to GnRH stimulation, suggest that the primary effect of 4-APP is to inhibit GnRH synthesis and/or release from the hypothalamus.

Sex steroids and bone density in premenopausal and perimenopausal women.

Bone density begins to decline in women before menopause, and the degree of bone loss is variable. We performed a cross-sectional analysis on the entry data of a 5-yr prospective study of risk factors for osteoporosis to determine the correlation of bone density with serum sex steroid concentrations and body weight. We studied 292 healthy white women, aged 35-50 yr, who were menstruating regularly or had had menses in the past 12 months. Blood samples were drawn in the early follicular phase for estradiol (E2), testosterone (T), dehydroepiandrosterone sulfate, and sex hormone-binding globulin (SHBG). Free levels of E2 (FE2) and T (FT) were calculated based on total T and E2, SHBG, and albumin levels. Women were classified as premenopausal (FSH, less than 12 U/L) and perimenopausal (FSH greater than or equal to 12 U/L; n = 46; 16%). Bone density was measured by dual photon absorptiometry of the lumbar spine (L2-L4) and hip and by single photon absorptiometry of the wrist. Perimenopausal women were older than premenopausal women (45.5 +/- 3.5 and 41.0 +/- 3.9 yr, respectively), but did not differ in height or weight. While bone density did not correlate with age in each group, perimenopausal women had significantly lower bone density at the L2-L4 and femoral neck (L2-L4, 1.18 +/- 0.14 in perimenopausal and 1.24 +/- 0.12 g/cm2 in premenopausal women; femur, 0.84 +/- 0.11 in perimenopausal and 0.90 +/- 0.11 g/cm2 in premenopausal women; P less than 0.005). Body weight showed the strongest positive correlation with bone density. Log FT, percent FT, and FE2 percent correlated positively with bone density, even after controlling for weight. Log SHBG was negatively correlated with bone density in premenopausal women at the hip and wrist after controlling for weight. FSH was inversely correlated with bone density, and E2 and T were lower in perimenopausal than premenopausal women. These data suggest that women who are still menstruating may have relative deficiencies in both E2 and T, with reduced bone densities as a consequence.

Essential fatty acid deficiency in four adult patients during total parenteral nutrition.

Four undernourished adults (15%-37% below idealll body weight) received fat-free total parenteral nutrition for a period of 6 to 8 weeks. Chemical evidence of essential fatty acid deficiency (triene:tetraene ratio greater than 0.4) appeared in all patients during the first 3 weeks of treatment. Deficiency developed more rapidly in the two patients who were younger (ages 16 and 36) and more severely undernourished (26% and 37% below ideal body weight) than in the two older patients (62 and 76) who were less undernourished (15% and 16% below idea body weight). All patients continued to gain weight and maintain positive nitrogen balance throughout the course of total parenteral nutrition and developing essential fatty acid deficiency. Hepatomegaly and increased serum liver enzyme activities occurred in the two patients with evidence of the most severe essential fatty acid deficiency. Liver biopsy, in the cases with hepatomegaly, showed hepatocytes containing fat and what appeared to be enlarged, spherical mitochondria. There was no cellular infiltrate or significant degree of necrosis. Supplementation with oral linoleic acid (as safflower oil) reversed the essential fatty acid deficiency and the elevation of serum liver enzymes.

Oxidized lipoprotein (a) induces cell adhesion molecule Mac-1 (CD 11b) and enhances adhesion of the monocytic cell line U937 to cultured endothelial cells.

Because of structural similarities between low density lipoproteins (LDL) and lipoprotein (a) (Lp(a)), we have investigated the properties and the functional activities of oxidized Lp(a) and focused on whether oxidized Lp(a), like oxidized LDL, can induce monocyte differentiation and adhesion of monocytic cells to endothelial cells grown in culture. Oxidized Lp(a), prepared in vitro by cupric ion oxidation, gave absorption curves of conjugated dienes with a lag-phase of 61.7 +/- 6.6 min (mean +/- S.D.) as compared to 85.2 +/- 7.2 min (n = 6, P < 0.01) for oxidized LDL from the same donors and at equimolar concentrations. Degradation of oxidized 125I Lp(a) by the monocytic cell line U937 at 37 degrees C was 1.6 +/- 0.3 nmol/g of cell protein, significantly (P < 0.01) greater than the degradation of oxidized 125I-LDL, which was 1.15 +/- 0.2 nmol/g of cell protein. Equimolar concentrations of oxidized Lp(a) and LDL inhibited the growth of U937 by 82 +/- 8.2% and 64 +/- 7.1%, respectively, when compared with the effect (negligible) produced by native Lp(a) and LDL. In addition, equimolar concentrations of oxidized Lp(a) and LDL induced adhesion molecule, Mac-1 (CD 11b), expression in U937 by 64 +/- 7.1% and 58 +/- 6.1% (P > 0.05), respectively, of the effect produced by phorbol esters (PMA) (P < 0.01). U937 cells incubated with oxidized Lp(a) and LDL, showed an adherence to cultured endothelial cells at 42 +/- 5.2% and 34 +/- 4.8%, respectively (P < 0.05), of the adherence shown by the same cells activated by PMA (P < 0.01). Our results suggest that oxidized Lp(a) like oxidized LDL plays an important role in the development of atherogenesis by inducing adhesion of monocytes to the arterial intimal and by stimulating intimal monocytes to differentiate into macrophages.

Paradoxical response of plasma lipoprotein(a) in patients undergoing cardiopulmonary bypass.

Plasma lipid, lipoprotein and apolipoprotein levels are known to decrease after major surgery. Coronary artery bypass surgery additionally involves use of extracorporeal circulation by use of a cardiopulmonary bypass pump, which necessitates hemodilution due to saline dextrose infusion to prime the pump. To investigate changes in lipids, lipoproteins and apolipoproteins as well as changes in C-reactive protein and albumin we conducted a study on 22 patients undergoing cardiac surgery involving cardiopulmonary bypass. Timed arterial blood samples were taken before, during and after cardiopulmonary bypass. At the onset and during cardiopulmonary bypass a rapid and significant fall was observed in all lipids and lipoproteins except lipoprotein(a) with recovery to near basal levels by 72 h for cholesterol, triglycerides, high density lipoprotein cholesterol and albumin, while apolipoproteins AI and B remained below basal levels during the postoperative period up to 72 h. In contrast, lipoprotein(a) levels increased at the onset, doubled during cardiopulmonary bypass and remained elevated postoperatively. On the other hand, C-reactive protein levels fell at the onset and during cardiopulmonary bypass but they became markedly elevated postoperatively. When results were corrected for hemodilution, the response patterns remained unchanged. As lipoprotein(a) is both atherogenic and thrombogenic, its elevation during cardiopulmonary bypass may be clinically important.

Marine lipid concentrate and atherosclerosis in the rabbit model.

Twenty-seven New Zealand white rabbits underwent balloon de-endothelialization of the aorta and iliac arteries while consuming a 2% cholesterol, 10% peanut oil rabbit chow. Ten of these rabbits were fed 1 ml of concentrated marine fish lipid (MaxEpaTm) daily. Six weeks after de-endothelialization, angiography of the treated arteries was performed and histologic cross-sections of the terminal aorta were measured with a planimeter. Iliac artery luminal diameters were also measured at consecutive 3-mm divisions from the aortic bifurcation and found to have a mean lumen diameter of 1.60 +/- 0.08 mm in the marine lipid-supplemented group (M) and 1.38 +/- 0.12 mm in the control group (C) (P less than 0.001). Analysis of variance on individual segmental diameters confirmed this difference. However, neither the angiographic diameters nor histologic, cross-sectional, luminal areas of the terminal aorta were different between groups. Instead, the mean cross-sectional area of the terminal aortic wall was significantly greater in the marine lipid-fed group (4.4 +/- 1.2 mm2 in M and 3.1 +/- 0.6 mm2 in C, P less than 0.01). In addition, the vessel wall area showed a positive correlation with red blood cell (RBC) incorporation of docosahexaenoic acid (r = 0.82, P less than 0.005) in both groups. In the M group, RBC eicosapentaenoic acid and docosahexaenoic acids increased 100% and 650%, respectively, over baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of specific radioimmunoassays for cyclosporine.

This study compares two recently introduced radioimmunoassay kits involving specific monoclonal antibodies to cyclosporine. One kit (Sandimmun) involved 3H-labeled CsA (3H-CsA) as tracer and the other (CY-CLO-Trac-SP) involved a 125I-labeled conjugated derivative of CsA. The kits were nearly equivalent in method performance characteristics. They produced superimposed standard curves and equivalent values to transplanted patient samples. Concentrations of CsA determined by either kit were apparently equivalent to values measured by high-performance liquid chromatography, suggesting that the specific monoclonal antibodies used with the kits detect in trough blood mainly native CsA. The 125I-labeled CsA, when compared with the 3H-CsA alternative, increased the sensitivity and precision, decreased the turnaround time, and provided a technically efficient and conveniently capable method of replacing HPLC for measuring native CsA.

Cyclosporine increases the oxidizability of low-density lipoproteins in renal transplant recipients.

Blood specimens from twenty-six renal transplant recipients treated with cyclosporine (CsA) were collected at weekly intervals, two months after transplantation. Specimens were grouped according to their CsA concentrations. Group I consisted of ten specimens with CsA concentration of >400 ng/ml; group II consisted of ten specimens with CsA concentrations ranging from 120-300 ng/ml; and group III consisted of six specimens with CsA concentrations of < 100 ng/ml. In addition, specimens from five renal transplant patients who, instead of CsA, received the immunosuppressant FK506 (group IV), and from six healty individuals were included. Plasma low-density lipoproteins (LDL) were isolated and their susceptibility to oxidation was studied by continuously monitoring the formation of conjugated dienes during copper ion-mediated oxidation. Patients with higher blood concentrations of CsA (groups I and II) had significantly higher oxidizability of LDL, as indicated by the shorter time required to start the oxidation (lag phase). The oxidizability of samples with low concentration of CsA (group III) was not significantly different from that of FK506-treated patients or healthy individuals. There was a negative correlation (r = -0702, P < 0.01) between oxidizability (lag phase) and CsA concentration in LDL. No correlation between blood CsA and plasma cholesterol or triglyceride concentration was evident during a three-month period postoperatively. Similarly, no correlation between the degree of oxidizability and plasma cholesterol or triglycerides was found at the time of the experiment. These findings suggest a prooxidant effect of CsA to plasma LDL, and may indicate that CsA is an important risk factor in the accelerated atherosclerosis of renal transplant recipients.

Predictive value of lipoprotein (a) and other serum lipoproteins in the angiographic diagnosis of coronary artery disease.

To determine the relation among lipids in predicting coronary artery disease (CAD), 213 patients undergoing diagnostic angiography for suspected CAD were prospectively studied. Twenty-one patients had normal coronary arteries and 192 had CAD in 1 to 3 arteries at arteriography with measurements obtained with digital calipers. Lipoproteins were measured and lipoprotein (a) [Lp(a)] was also assayed in a subset of 98 patients with CAD. Statistical analysis was performed using uni- and multivariate techniques to test the association among age, gender, systemic hypertension, diabetes mellitus, cigarette smoking, family history, total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low density lipoprotein cholesterol, apolipoproteins (apo) A-I and apo B, ratio of apo A-I to apo B, and ratio of HDL cholesterol to total cholesterol, to Lp(a) and to CAD. All factors except gender, systemic hypertension, diabetes mellitus and cigarette smoking were univariate predictors of CAD. Multivariate predictors were, in decreasing order of significance, family history, age, HDL/total cholesterol ratio and apo B. When Lp(a) was included, multivariate predictors were age, family history, apo B and Lp(a), in that order. Lipid parameters alone showed that the HDL/total cholesterol ratio and that Lp(a) provide the best predictive tests for the detection of CAD in this referral population and may ultimately become important screening tests for CAD.

Usefulness of serum lipoprotein (a) as a predictor of restenosis after percutaneous transluminal coronary angioplasty.

Serum lipoprotein (a) (Lp[a]) has been associated with coronary artery atherosclerosis. Its association with restenosis after percutaneous transluminal coronary angioplasty (PTCA) has not been previously studied. Serum levels of Lp(a), in addition to other lipoproteins, and their components using standard assays, were determined in subjects undergoing cardiac catheterization within 10 months after PTCA. Clinical (e.g., sex, diabetes, angina class) and angiographic (e.g., PTCA percent diameter reduction) factors were not different between the group without (diameter reduction less than 50%; group A) and the group with (diameter reduction greater than or equal to 50%; Group B) restenosis. Total cholesterol, triglycerides, high- and low-density lipoprotein cholesterol, apolipoprotein A-I, apolipoprotein B and Lp(a) were compared. Univariate predictors of restenosis were serum triglycerides (2.50 +/- 1.07 mmol/liter for group A vs 1.72 +/- 0.79 +/- mmol/litre for group B, p = 0.008), and Lp(a) (median: 7.0 mg/dl [range 0 to 44] for group A vs 19 mg/dl [range 1 to 120] for group B; p = 0.006). Stepwise logistic regression revealed the only significant independent predictor of restenosis to be serum Lp(a) (p = 0.018). Each quintile of Lp(a) was associated with a progressively higher risk of restenosis, with the highest quintile (40 to 120 mg/dl) having an odds ratio of 11 (95% confidence interval 9 to 13) compared with the lowest quintile (0 to 3.9 mg/dl) (p = 0.033). A serum Lp(a) of greater than 19 mg/dl was associated with an odds ratio of 5.9 (95% confidence interval 4.6 to 7.2) (restenosis rates of 58% in the group with 0 to 19 mg/dl and 89% in the group with 19 to 120 mg/dl; p = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Automated immunohistochemical estrogen receptor in fixed embedded breast carcinomas.

The authors immunohistochemically assessed the presence of estrogen receptor (ER) in formalin-fixed, paraffin-embedded tissue sections of 68 breast carcinomas by an automated method using Pronase (CalBiochem, La Jolla, CA) predigestion and alkaline phosphatase detection (Method 1). These results were compared with those obtained by an automated peroxidase-antiperoxidase method with DNAse pretreatment of fixed embedded sections (Method 2), with ER immunostain on frozen sections (Method 3), and with biochemical results (dextran-coated charcoal cytosolic [DCC] assay). Compared with the DCC assay, Methods 1, 2, and 3 gave sensitivities of 54%, 25%, and 89%, respectively. The sensitivity for Method 1 was increased to 74% in those cases with DCC results showing greater than 50 fmol/mg protein. These findings indicate that ER immunohistochemical studies on formalin-fixed paraffin-embedded tissues (as assayed by Method 1) provide useful clinical information when the results are positive. A negative result, especially if surrounding normal elements are not positive, may indicate no receptors, receptor levels less than 50 fmol/mg protein, or improper tissue preservation. In the absence of fresh tissue for ER assay by DCC assay or of frozen sections for immunostaining, and with an understanding of its limitations, this method may be useful.

Automated immunohistochemical estrogen receptor in fixed embedded breast carcinomas. Comparison with manual immunohistochemistry on frozen tissues.

Estrogen receptor (ER) status of breast carcinomas determines prognosis and treatment. Biochemical ER assays are expensive and time-consuming and require fresh tumor. Immunohistochemical ER was assessed in 68 breast carcinomas, by an automated method using routinely processed formalin-fixed paraffin-embedded tissues, and manually with the use of snap-frozen tissues with a monoclonal anti-ER and peroxidase-antiperoxidase technique. The paraffin sections were digested with DNase to enhance development of signal. Positive nuclear ER was obtained in 9 (13%) fixed tissues and 36 (53%) frozen tissues. The sensitivity, specificity, and predictive value of a positive test result, as compared with the biochemical assay, were 25%, 100%, and 100% for the paraffin section technique, and 89%, 88%, and 89% for the frozen sections. Although it is specific, lack of sensitivity, resulting from loss of ER with fixation and room temperature handling, renders this immunohistochemical technique unacceptable on fixed tissues. However, ER immunostain on frozen tissue is an acceptable alternative to biochemical assay.

Immunohistochemical progesterone receptor assay. Measurement by image analysis.

To determine the efficiency of image analysis in immunohistochemical progesterone receptor (PgR) measurement, 94 primary breast carcinoma tissue samples were evaluated for PgR by biochemical dextran-coated charcoal assay (DCC) and an immunohistochemical method. Frozen sections immunostained for PgR with a monoclonal antibody (Abbott PgR-ICA, Chicago, IL) and the peroxidase-antiperoxidase technique were scored semiquantitatively histologic score by microscopy and quantitatively (percentage nuclear area immunopositivity [PNA] using the CAS 200 image analyzer (Cell Analysis Systems, Elmhurst, IL). There was a positive correlation between dextran-coated charcoal assay and both histologic score (r = 0.82) and PNA (r = 0.69). Selected cutoff points of 60 histologic score and 6.5% PNA based on sensitivity/specificity calculations yielded a predictive value of a negative test of 73% and 80%, respectively, and a positive predictive value of 100% for both; ranges of fmol/mg protein PgR correspond to ranges of histologic score and PNA. The use of an image analyzer to measure PNA in PgR-immunostained sections is a viable alternative to dextran-coated charcoal assay, especially when insufficient fresh tissue is available.

A simple ultrafiltration method for determining unbound estradiol in serum.

The Amicon MPS-1 centrifugal ultrafiltration device and the YMT membrane were used to measure free estradiol in serum. Two independent assays were required. The first measured total estradiol-17 beta and the second ultrafiltrable fraction. The unbound fraction was determined by counting [3H]estradiol-17 beta in 0.15-0.3 mL ultrafiltrates of 0.5 to 1 mL of serum that had been equilibrated with [3H]estradiol-17 beta at 37 degrees C. The assay is rapid (1 h), practicable (requires 0.6 mL serum) and reproducible (CV 4.6% within assay and 6.5% between assays). Samples from apparently healthy men and women and from pregnant women gave results that agreed with those obtained by equilibrium dialysis. The percentages of free serum estradiol-17 beta were similar during both early and late follicular phases of the menstrual cycle. Samples from women with hirsutism gave values for total and free estradiol-17 beta which were not significantly different from those of normal females when no consideration was given to the phase of the menstrual cycle. The means for both of these female groups were significantly different from those of males.

Comparison of phosphotungstate and dextran sulfate-Mg2+ precipitation procedures for determination of high density lipoprotein cholesterol.

Because of the controversy over the best method for assaying high density lipoprotein (HDL) cholesterol in the clinical laboratory, a commonly used phosphotungstate method for precipitating low density and very low density lipoproteins (LDL and VLDL) was compared with a recently recommended dextran sulfate precipitation method. The accuracy and precision of HDL cholesterol determinations were similar for both methods. Either of these procedures would appear to be equally satisfactory for the assay of HDL cholesterol in the clinical laboratory.

Parallel assays of beta-endorphin and ACTH in Cushing's patients undergoing petrosal sinus sampling.

This study explores the possibility of improving endocrinologic testing during petrosal sinus catheterization by determining both beta-endorphin and corticotropin (ACTH). We studied 14 patients with Cushing's disease, two with adrenal tumor, and three with ectopic tumors secreting ACTH. In patients with Cushing's disease, beta-endorphin concentrations paralleled those of ACTH in all basal plasma samples collected either from petrosal sinuses or peripheral veins. Individual responses of beta-endorphin and ACTH to corticotropin releasing hormone (CRH) were closely related to the presence of a corticotroph adenoma. In such patients, a consistently higher concentration of beta-endorphin over ACTH was observed in all samples collected either from petrosal sinuses or peripheral veins; the ratios were unchanged after the administration of CRH. In patients with ectopic ACTH secretion, the mean ratio of beta-endorphin over ACTH (with both values expressed in pmol/L) was significantly higher (3.5) than that of patients with Cushing's disease (2.9) or Cushing's syndrome due to adrenal tumor (2.7).

Elevated free testosterone levels in women with acne.

Female patients with varying grades of acne were examined to determine whether free testosterone levels were a more sensitive indicator of hyperandrogenism than total testosterone values. Of 24 women with acne studied, four were found to have elevated total testosterone levels, whereas 11 had elevated free testosterone levels. Twenty-four age-matched female control subjects without acne, hirsutism, or irregular menstrual cycles all had normal free and total testosterone values. The mean concentration of free testosterone in the patients with acne was 1.035 ng/dL, while in the control subjects it was 0.54 ng/dL. Other than hirsutism in three patients with acne with elevated free testosterone levels, there were no morphologic clues identified to determine which patients with acne are more likely to have abnormal free testosterone levels. The free testosterone level did not correlate with the type, distribution, or severity of the acne present in the patients.