Antioxidant Potential, DNA Damage, Inflammation, Glycemic Control and Lipid Metabolism Alteration: A Mediation Analysis of Islamic Sunnah Intermittent Fasting on Cognitive Function among Older Adults with Mild Cognitive Impairment

OBJECTIVES

This study aimed to determine the relationship between oxidative stress, DNA damage, inflammation, and metabolic biomarkers as the mediating factor between Islamic Sunnah intermittent fasting (IF) practice and cognitive function among older adults with mild cognitive impairment (MCI).

DESIGN

This study was a 36 months prospective cohort study.

SETTING

Community-dwelling older participants recruited through a stratified random sampling method from four states representing Malaysia's central, north-west, northeast and southern regions.

PARTICIPANTS

Ninety-nine Malay Muslim older adults (n= 99) aged 60 and above with MCI and no known critical illnesses were included in the current analysis. The participants were divided into regularly practicing IF (r-IF), irregularly practicing IF (i-IF) and not practicing IF (n-IF) groups.

MEASUREMENTS

Fasting venous blood was collected and used to determine the levels of oxidative stress, DNA damage, inflammatory and metabolic biomarkers. Mini-Mental State Examination, Montreal Cognitive Assessment, Rey Auditory Verbal Learning Test, Digit Span and Digit symbol were used to evaluate the cognitive function. Then, the mediation analysis was conducted using a multistep regression model to determine the mediating role of various biomarkers between IF practice and cognitive function.

RESULTS

When comparing the r-IF and n-IF groups, higher SOD activity, lower DNA damage (percentage of DNA in tail), lower CRP levels and higher HDL-cholesterol levels established partial mediation while lower insulin levels established complete mediation between IF practice and better cognitive function. Meanwhile, when comparing the r-IF and i-IF groups, higher SOD activity and lower CRP levels completely mediated the effects of IF practice on better cognitive function.

CONCLUSION

It can be concluded that changes in antioxidant function, DNA damage, inflammation and a limited set of metabolic biomarkers (insulin and HDL cholesterol) may mediate improvements in cognitive function among older participants with MCI who practice Islamic Sunnah IF.

The fingerprint nature of PCDD in iron ore sinter strand emissions, the effect of suppressants and alternative fuels, and the potential for comparison with the isomer profile of PCDF

It has been previously shown that the isomer profile of PCDF emissions from iron ore sinter plant only varies within limits even when suppressants or alternative fuels are added, to the extent that it can be said to have a 'fingerprint'. The isomer profiles of PCDD from tetra- to hexacholrodibenzo-p-dioxin from the same samples examined for PCDF emissions have been obtained, and show the same tendency for a 'fingerprint ' isomer distribution to occur. Occasional exceptionally high isomer abundances are observed, but these are uncommon. The potential for comparison of the abundances of PCDF and PCDD isomers with similar chlorination patterns to determine whether the same formation process is involved has been examined. It is found that co-elutions prevent extensive comparisons irrespective of whether the SP2331 or DB5ms column is used in the analyses for separation of isomers to provide the results used for comparisons, although they allow limited results to be obtained. It is suggested that analyses using the two chromatography columns to analyse the same sample in parallel could provide more resolution of the isomer profiles for use in comparisons. A pilot study using samples analysed using each column is limited because of detailed differences in the emissions profiles, but demonstrates that greater resolution is possible if the two columns are used to analyse one sample.

The polychlorinated dibenzofuran fingerprint of iron ore sinter plant: Its persistence with suppressant and alternative fuel addition

An earlier demonstration that the relative concentrations of isomers of polychlorinated dibenzofuran do not vary as the flamefront of an iron ore sinter plant progresses through the bed, and profiles are similar for two sinter strands has been widened to include studies of the similarity or otherwise between full scale strand and sinter pot profiles, effect of addition of suppressants and of coke fuel substitution with other combustible materials. For dioxin suppressant addition, a study of the whole of the tetra- penta- and hexaCDF isomer range as separated by the DB5MS chromatography column, indicates no significant change in profile: examination of the ratios of the targeted penta- and hexaCDF isomers suggests the profile is similarly unaffected by coke fuel replacement. Addition of KCl at varied levels has also been shown to have no effect on the 'fingerprint' and there is no indication of any effect by the composition of the sinter mix. The recently published full elution sequence for the DB5MS column is applied to the results obtained using this column. It is confirmed that isomers with 1,9-substitution of chlorine atoms are invariably formed in low concentrations. This is consistent with strong interaction between the 1 and 9 substituted chlorine atoms predicted by DFT thermodynamic calculations. Non-1,9-substituted PCDF equilibrium isomer distributions based on DFT-derived thermodynamic data differ considerably from stack gas distributions obtained using SP2331 column separation. A brief preliminary study indicates the same conclusions (apart from the 1,9-interaction effect) hold for the much smaller content of PCDD.

PCSK9 and triglyceride-rich lipoprotein metabolism

Pro-protein convertase subtilisin-kexin 9 (PCSK9) is known to affect low-density lipoprotein (LDL) metabolism, but there are indications from several lines of research that it may also influence the metabolism of other lipoproteins, especially triglyceride-rich lipoproteins (TRL). This review summarizes the current data on this possible role of PCSK9. A link between PCSK9 and TRL has been suggested through the demonstration of (1) a correlation between plasma PCSK9 and triglyceride (TG) levels in health and disease, (2) a correlation between plasma PCSK9 and markers of carbohydrate metabolism, which is closely related to TG metabolism, (3) an effect of TG-lowering fibrate therapy on plasma PCSK9 levels, (4) an effect of PCSK9 on postprandial lipemia, (5) an effect of PCSK9 on adipose tissue biology, (6) an effect of PCSK9 on apolipoprotein B production from the liver and intestines, (7) an effect of PCSK9 on receptors other than low density lipoprotein receptor (LDLR) that are involved in TRL metabolism, and (8) an effect of anti-PCSK9 therapy on serum TG levels. The underlying mechanisms are unclear but starting to emerge.

Implementation of a consent for chart review and contact and its impact in one clinical centre

OBJECTIVE

Informed consent and protection of patient confidentiality are central to the conduction of clinical research. Consent for chart review and contact (CCRC) allows a patient chart to be screened for research by persons outside the direct circle-of-care and for the patient to be contacted regarding potential studies. This study describes the process of implementation and benefits of such a consent.

DESIGN

We present a descriptive report of a CCRC document that was created and presented to patients over a 3.5-year period at a tertiary care Endocrinology and Metabolism centre. To assess the potential impact of such a document on patient recruitment, the basic demographics of patients who did and did not consent were compared. In addition, we compared the recruitment rate at our centre, using our novel approach, with that at other centres for an ongoing study of patients with type 1 diabetes.

RESULTS

A large proportion (6501/8025, or 81%) of patients gave their consent for chart review. Patients who denied consent were more likely to be women and older. Compared with other centres, our centre recruited at the highest rate for a known study of patients with type 1 diabetes. The majority (46/60, or 76.7%) of patients were recruited via the novel approach.

CONCLUSIONS

Consent for chart review and contact addresses several important ethical issues regarding the use of patient clinical information for research purposes. Our study demonstrated how such a process can be implemented.

Relationship between testosterone, estradiol and circulating PCSK9: Cross-sectional and interventional studies in humans

BACKGROUND

Circulating PCSK9 levels are higher in women than men, in postmenopausal than premenopausal women, and in pregnant than non-pregnant women, suggesting that sex hormones may be related to PCSK9 levels. We have examined the relationship between serum estradiol (E2) and testosterone (T) and PCSK9, and the impact of E2 replacement therapy in women and T replacement and ablation therapy in men on circulating PCSK9.

METHODS

We conducted a cross-sectional study to examine the correlation between serum T (in males) and E2 (in females) and serum PCSK9. We also conducted interventional studies to examine the effect of hormonal therapy on serum PCSK9 levels.

RESULTS

In men, (1) serum T does not correlate with circulating PCSK9 or with LDLC in the basal state, (2) T replacement therapy does not have any effect on circulating PCSK9, and (3) T ablation therapy has mixed results. In women, (1) E2 correlates inversely with circulating PCSK9 and directly with serum LDLC, but (2) E2 replacement therapy does not have any effect on circulating PCSK9.

CONCLUSIONS

We demonstrate differences between men and women in the relationship of their major sex hormones with circulating PCSK9. In men, circulating PCSK9 is not related to or affected by T except for a possible effect during T ablation therapy. In women, E2 is inversely related to circulating PCSK9 but the lack of effect of E2 therapy on circulating PCSK9 suggests that the E2-related differences in PCSK9 levels may be the result of differences in receptor-mediated PCSK9 clearance through E2-induced changes rather than production of PCSK9. The studies were registered with ClinicalTrials.gov NCT00848276.

Effect of fibrates on postprandial remnant-like particles in patients with combined hyperlipidemia

We have investigated the effect of standard doses of two fibrates, gemfibrozil and fenofibrate, on fasting and postprandial remnant-like particles (RLP) in subjects with combined hyperlipidemia. Forty-eight subjects participated; of these, 14 underwent a Vitamin A-fat loading test before and after 6 months of treatment with gemfibrozil (n = 8) and fenofibrate (n = 6). Blood was drawn every 2h for 12h after the test meal. The postprandial response was calculated as the area under the curve (AUC). There was no difference in fasting levels and pre-treatment AUC for triglycerides (TG), RLP cholesterol (RLP-C), RLP triglycerides (RLP-TG) and retinyl palmitate (RetP) between the two treatment groups. There was also no difference in the treatment effect on all parameters between the two treatment groups. Combining the two treatment groups, treatment resulted in a significant reduction in fasting levels and AUC of all four parameters. Assigning the difference observed between pre-treatment AUC of the combined study group and AUC of a normolipidemic (NL) control group as 100%, fibrate treatment resulted in decreases in AUC for TG, RLP-C, RLP-TG and RetP of 68, 69, 69 and 94%, respectively. These results indicate that fibrates are effective agents in reducing the postprandial increase in remnant lipoprotein particles.

Liver fibrosis attributed to lipid lowering medications: two cases

We identified two cases of chronic active hepatitis with liver fibrosis induced by lipid lowering drugs of the statin and fibrate classes despite regular monitoring of transaminases. There are few reports of clinically significant hepatitis induced by these drugs and even fewer cases of fibrosis. Given the growing use of these drugs, there are implications for monitoring patients on long-term therapy for liver damage.

Postprandial remnant-like lipoproteins in hypertriglyceridemia

It has been proposed that remnants of chylomicrons and very-low-density lipoproteins (VLDL) are atherogenic. We have used an immunochemical method to isolate remnant-like particles (RLP) and measured them in terms of their cholesterol and triglycerides (TG). RLP consist of apoB-48-containing triglyceride-rich lipoproteins and remnant-like VLDL containing apoB-100. The study aim was to look for information from postprandial RLP data that could not be known from other markers of triglyceride-rich lipoproteins and fasting TG and RLP data alone. A total of 41 subjects were studied. Eight subjects had hypertriglyceridemia (HTG) and low high-density lipoprotein (HDL), 14 had combined hyperlipidemia (CH), 5 had the apo E2/2 genotype receiving gemfibrozil, 10 were normolipidemic (NL) controls, and 4 had hypercholesterolemia. As a whole group, there was correlation among 1) fasting TG, RLP cholesterol (RLP-C), and RLP-TG but not VLDL apo B100, VLDL apo B48 and their respective postprandial responses measured as incremental area under the curve (IAUC), 2) fasting TG and postprandial IAUC of RLP-C and RLP-TG, 3) RLP-C IAUC, RLP-TG IAUC, and TG IAUC, retinyl palmitate (RP) IAUC, and VLDL apo B48 IAUC but not VLDL apo B100 IAUC. The HTG/low HDL-C and CH groups had higher IAUC for RLP-C, RLP-TG, TG, and RP than the NL group. Fasting and postprandial RLP were triglyceride enriched in the HTG/low HDL-C group and to a lesser extent in the CH group. The HTG/low HDL-C and CH groups had a delay in their RLP-C but not RLP-TG peaks suggesting a delay in hepatic clearance of RLP and/or a protracted period of lipolysis and/or processing of RLP. The fasting and postprandial RLP-C/RLP-TG and RLP-C/TG ratios were elevated in the apo E2/2 group in spite of gemfibrozil therapy. The increment in postprandial RLP was, however, not exaggerated. Our data indicate that 1) postprandial RLP lipemia is enhanced in HTG subjects when compared with NL subjects, 2) postprandial RLP lipemia is proportional to fasting RLP and TG levels and mirrors, to a large extent, increases in postprandial TG, RP, and VLDL apo B48 but not VLDL apo B100, 3) there are compositional differences in fasting and postprandial RLP in the three forms of HTG studied, RLP being triglyceride enriched in the HTG/low HDL-C group and to a lesser extent in the CH group, and cholesterol-enriched in the apo E2/2 group, and 4) apo E2/2 subjects had high fasting and postprandial RLP-C concentrations in spite of being on treatment with gemfibrozil and having normal fasting and postprandial TG concentrations.

The atherogenic significance of an elevated plasma triglyceride level

The importance of hypertriglyceridemia as an independent predictor of coronary artery disease (CAD) remains unsettled. Hypertriglyceridemia, with or without associated hypercholesterolemia, occurs more frequently in premature CAD subjects than does hypercholesterolemia alone. With univariate analysis, most studies show a positive correlation between plasma triglyceride (TG) level and risk for CAD, but with multivariate analysis plasma TG level is no longer an independent risk factor except in women and diabetics. Prospective studies have shown that subjects with a high LDL/HDL cholesterol ratio and a high plasma TG level have the highest risk for CAD. Hypertriglyceridemia signifies the presence of excess triglyceride-rich lipoproteins (TRL), including chylomicrons, VLDL, and their remnants. The question then becomes one of whether TRL are directly or indirectly involved in atherogenesis. TRL were thought to be too big to infiltrate the arterial wall, and histopathological studies have shown cholesterol but not triglyceride accumulation in the atherosclerotic plaque. However, there was a recent demonstration of undegraded VLDL and IDL in atherosclerotic plaques. Larger TRL may undergo hydrolysis on the arterial surface to become smaller particles before entry into the intima. Possible cellular pathways for the uptake of TRL by macrophages have been described. The smaller TRL (Sf 20-60), including postprandial chylomicron remnants, are believed to be the most atherogenic of all TRL particles. Because large amounts of TRL are produced in the postprandial period, atherogenesis involving TRL may be primarily a postprandial phenomenon. Once in the intima, TG may undergo hydrolysis, releasing free fatty acids and mono- and diacyl glycerol, accounting for the dearth of TG in atherosclerotic lesions. Particle for particle, VLDL delivers five times as much cholesterol as LDL does to the macrophage.

Successful Long-Term Management of a Gonadotroph Adenoma with Bromocriptine

OBJECTIVE

To report the successful 10-year management of a gonadotroph macroadenoma with bromocriptine and review the management of gonadotroph adenomas with bromocriptine.

METHODS

We present a case and review the pertinent literature. The effectiveness of bromocriptine in the management of gonadotroph adenomas is evaluated.

RESULTS

A 62-year-old man was found to have a pituitary tumor after seeking medical assistance because of a 6-month history of headaches and blurred vision. He had decreased visual acuity and bitemporal field defects. Serum follicle-stimulating hormone (FSH) levels were increased, whereas serum luteinizing hormone and total testosterone levels were normal. Treatment with bromocriptine resulted in a decrease in serum FSH levels, complete resolution of his symptoms, and considerable improvement in his visual acuity and visual field defects. Treatment with only bromocriptine for 10 years resulted in maintenance of normal serum FSH levels and no recurrence of symptoms.

CONCLUSION

In the management of a gonadotroph adenoma, we recommend consideration of a therapeutic trial of bromocriptine. In cases that are refractory to this therapy, surgical treatment or external pituitary irradiation could then be used.

Efficacy and safety of a new hydroxymethylglutaryl-coenzyme A reductase inhibitor, atorvastatin, in patients with combined hyperlipidemia: comparison with fenofibrate

This 24-week, randomized, open-label multicenter study evaluated the efficacy and safety of atorvastatin compared with fenofibrate in the treatment of patients with combined hyperlipidemia (CHL). Following a 6-week baseline period, 84 patients with CHL were randomly assigned to either atorvastatin treatment, 10 mg QD for 12 weeks increasing to 20 mg QD for 12 weeks, or fenofibrate treatment, 100 mg TID for 24 weeks. Changes from baseline in lipid parameters were evaluated at weeks 12 and 24. At both 10- and 20-mg doses, atorvastatin treatment resulted in significantly greater reductions in LDL cholesterol, apolipoprotein (apo) B, total cholesterol, LDL-apoB, and lipoprotein-B compared to 300-mg fenofibrate treatment (P < .05). While atorvastatin also resulted in clinically significant reductions in triglyceride, VLDL cholesterol, apoB in VLDL, triglyceride in VLDL, and apoC-III and significant increases in HDL cholesterol and apoA-I levels, fenofibrate was more effective than atorvastatin in altering all these parameters. However, by significantly affecting both the cholesterol-rich and triglyceride-rich particles, atorvastatin holds promise as a lipid-regulator able to adequately treat a broad range of patients that includes those with CHL.

High frequency of mutations in the human lipoprotein lipase gene in pregnancy-induced chylomicronemia: possible association with apolipoprotein E2 isoform

Partial deficiency in lipolysis usually results in only mild disturbances of lipid levels. However, when this is associated with impairment of the uptake of remnant particles and increased production of triglyceride-rich lipoproteins stimulated by environmental factors such as during normal pregnancy, chylomicronemia may ensue. We have previously reported a patient who had approximately 12% of normal LPL activity and developed severe chylomicronemia during pregnancy (Ma et al. 1993. J. Clin. Invest. 91: 1953-1958). Here we report four new patients with pregnancy-induced chylomicronemia. In the nonpregnant state, these patients had mild to modest elevation of triglyceride levels ranging from 80 to 623 mg/dl (0.9-7.0 mmol/l) but during the third trimester they became severely chylomicronemic with triglyceride levels ranging from 2314 to 14,596 mg/dl (26 to 164 mmol/l). Three of these four patients had partial lipoprotein lipase (LPL) deficiency. The molecular characterization of the LPL gene in these three patients with partial LPL deficiency revealed four novel unpublished mutations. Patient #1 is a compound heterozygote for Leu252Arg and Ala261Thr mutations which are associated with 25% of normal LPL activity. In addition, she has an apoE3/2 genotype. Patient #2 is a heterozygote for a Asn291Ser substitution with 69% of LPL activity and also has an apoE3/2 genotype, while patient #3 is a heterozygote for a Trp382Stop mutation with 54% of normal LPL activity and has an apoE4/2 genotype. The fourth patient (#4) with pregnancy-induced chylomicronemia does not have LPL deficiency and has an apoE3/3 genotype. The previously reported patient (#5) who had 12% of normal LPL activity due to homozygosity for a Ser172Cys mutation also has an E3/3 genotype. Our data suggest that mutations in the LPL gene that cause partial LPL deficiency might be a frequent factor in the pathogenesis of pregnancy-induced chylomicronemia.

The standardization of estrogen receptors

Tumour estrogen receptor (ER) status may determine the medical treatment of a patient with breast cancer; yet inter-laboratory results can vary markedly, particularly when absolute cut-offs in fmol/mg cytosol protein are used. The use of standardized log units is proposed to permit greater inter-laboratory comparability. We have assessed the biochemical ER values using the dextran-coated charcoal method with three data sets, two quality control (QC) sets for Ontario laboratories and a data set with values for 184 primary breast cancer patients seen at Women's College Hospital (WCH) between 1985 and 1986. The distributions for all the raw data were skewed toward the lower end of the range; a log transformation improved the symmetry of the distributions. There was marked inter-laboratory variation in the QC data, and standardized log units greatly reduced this variability. The WCH data had similar differentiation by tumour size and nodal status with both the raw data and standardized log units. However, standardized log units provided more consistent evidence of an association between ER and immunohistochemical ERICA. The standardized log units provide quantitative receptor values suitable for multi-centre research, for future work with clinical outcomes, and for the daily management of patients.

Effect of gemfibrozil and lovastatin on postprandial lipoprotein clearance in the hypoalphalipoproteinemia and hypertriglyceridemia syndrome

Eleven men with hypoalphalipoproteinemia (HPAL; fasting plasma high density lipoprotein (HDL) cholesterol level of < 0.9 mmol/l), mild hypertriglyceridemia (HTG; triglycerides (TG) level of 1.75-7.5 mmol/l) and a normal calculated LDL cholesterol level (< 3.7 mmol/l) participated in a randomized, double-blind, double-placebo, crossover trial to compare the effect of two drugs, lovastatin (40 mg once daily) and gemfibrozil (600 mg twice daily), on clearance of postprandial lipoproteins. A 2-week washout period separated drug treatment periods of 6 weeks each. Ten subjects completed each treatment period. After ingestion of a vitamin A fat load, plasma, chylomicron and non-chylomicron retinyl palmitate (RP) and TG responses (areas under curves) were reduced in all subjects on gemfibrozil therapy and in 7 on lovastatin therapy. There was close correlation between change in fasting TG (but not fasting HDL-cholesterol) and change in postprandial RP areas on gemfibrozil but not lovastatin therapy. Postheparin lipoprotein lipase (LPL) and hepatic lipase (HL) activities were increased by gemfibrozil therapy while only a mild elevation in LPL activity alone was seen on lovastatin therapy. These data indicate that improvement in HTG is the main feature associated with improvement in postprandial lipemia and this is likely due to LPL-mediated enhancement of lipolytic hydrolysis. Gemfibrozil is more effective than lovastatin in attenuating postprandial lipemia in the HPAL/HTG syndrome.

Evidence for bimodal distribution of breast carcinoma ER and PgR values quantitated by enzyme immunoassay

Breast carcinoma oestrogen receptor (ER) and progesterone receptor (PgR) values obtained by radioligand binding assays have commonly been observed to have approximate log-normal distributions. We examined the distribution of log-transformed receptor values obtained by enzyme immunoassay for 5468 primary breast carcinomas in five Ontario laboratories. In each laboratory, it was found that the frequency histograms for the log transformed receptor values were not unimodal, and generally were suggestive of bimodality. This was not affected by stratification by age or inferred menopausal status (< or = 49, > or = 50 years), and could not be explained by kit characteristics. However, the low point in the distribution varied from 5 to 63 fmol/mg cytosol protein, depending on the receptor, patient age and laboratory. The tendency towards biomodality was more distinct for ER than for PgR. It remains to be determined whether the low points on the frequency histograms have clinical relevance for discriminating between hormone-sensitive and hormone-insensitive tumours.

Underrecognition of chylomicronemia as a cause of acute pancreatitis

OBJECTIVE

To determine how often chylomicronemia is considered by admitting physicians as a possible cause of acute pancreatitis.

DESIGN

Retrospective hospital chart review.

SETTING

Tertiary care teaching hospital in an urban centre with a referral population of 1 million.

PATIENTS

All patients admitted with acute pancreatitis from Jan. 1, 1985, to Dec. 31, 1987. Episodes of pancreatitis were divided into two groups: those for which a cause was known after history taking, physical examination and laboratory investigation at the time of admission (group 1) and those for which a cause was unknown after full examination (group 2).

RESULTS

There were 319 episodes of chylomicronemia in 162 patients. The cause of the pancreatitis was known after examination at the time of admission in 239 (75%) of the episodes; there was hypertriglyceridemia in 7 (3%). No cause was identified after examination in the other 80 episodes (25%); chylomicronemia was considered in 18 cases (29%) and was found in 6 (33%) of them (mean serum triglyceride level 34.4 mmol/L). Of the remaining 62 episodes in group 2, 10 (16%) were later found to be caused by chylomicronemia (mean serum triglyceride level 22.6 mmol/L). Among the 80 episodes in group 2 at least one medical condition associated with chylomicronemia was present in 24. In only 7 (29%) of the 24 was chylomicronemia considered; in 6 the mean serum triglyceride level was 19.7 mmol/L.

CONCLUSIONS

Although the overall detection rate of chylomicronemia was low, its presence in patients without other etiologic factors after examination may have been much higher. Consideration of chylomicronemia in this subgroup at the time of presentation may increase diagnostic yield and help prevent further occurrences of pancreatitis.

Delayed clearance of postprandial chylomicrons and their remnants in the hypoalphalipoproteinemia and mild hypertriglyceridemia syndrome

Hypoalphalipoproteinemia (HPAL) with mild hypertriglyceridemia (HTG) is associated with increased coronary artery disease (CAD) risk. The aim of this study was to examine the metabolism of postprandial lipoproteins in HPAL/HTG subjects (n = 21). They had a fasting plasma high density lipoprotein (HDL) cholesterol level < 0.9 mmol/l, a triglycerides (TG) level of 2.0-7.1 mmol/l, and a normal low density lipoprotein (LDL) cholesterol level (< 3.7 mmol/l). They were either homozygous for apoprotein E3 (n = 13) or heterozygous for apoprotein E4 (n = 5) or E2 (n = 3). After ingestion of a vitamin A fat load, plasma and chylomicron (CM) retinyl palmitate (RP) response (areas under curves) was three times and non-CM RP response 2.5 times greater than in normolipidemic control subjects (n = 13). There was close correlation between fasting plasma TG level and postprandial RP response in HPAL/HTG subjects (plasma, r = 0.87; CM, r = 0.89; and non-CM, r = 0.84). In control subjects this correlation was present for plasma RP (r = 0.80) and CM RP (r = 0.61) but not for non-CM RP (r = 0.53). In contrast, postprandial RP response was not correlated with fasting plasma HDL cholesterol levels for both groups. There was also no correlation between fasting TG and fasting HDL cholesterol. Postheparin lipoprotein lipase and hepatic lipase activities were slightly higher in HPAL/HTG subjects. The pattern of postprandial change in HDL composition was similar to that in control subjects. These data indicate enhanced postprandial lipemia in the HPAL/HTG syndrome, and this may account for their increased CAD risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Coexisting pheochromocytomas and adrenocortical tumour discovered incidentally

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Falsely high high-density lipoprotein triglyceride values by the heparin-manganese precipitation method

Recent evidence indicates that high-density lipoprotein triglyceride (HDL-Tg) may be a predictor of coronary artery disease. We examined three methods for HDL-Tg measurement, comparing results obtained by measurement of Tg in the supernate after heparin-manganese chloride (heparin-Mn) precipitation of EDTA-treated plasma (I) with results obtained after preparative ultracentrifugation (II and III). In II, we used heparin-Mn precipitation of low-density lipoprotein (LDL) from the infranate after ultracentrifugation at d 1.006 to remove very-low-density lipoprotein (VLDL). In III, we performed sequential flotation ultracentrifugation at d 1.006 and 1.063, then measured Tg in the d greater than 1.063 fraction. Method I gave significantly higher HDL-Tg results than II and III, which gave essentially identical results. The difference in results between I and II was not caused by the presence of heparin or manganese chloride, because these were used in both methods. Prior removal of VLDL in II and III resulted in lower HDL-Tg values, and subsequent removal of LDL by precipitation or ultracentrifugation did not alter final HDL-Tg values. The higher values obtained in I were the result of the presence of VLDL-rich unsedimented precipitate in the supernate.

Falsely high high-density lipoprotein triglyceride values by the heparin-manganese precipitation method

Recent evidence indicates that high-density lipoprotein triglyceride (HDL-Tg) may be a predictor of coronary artery disease. We examined three methods for HDL-Tg measurement, comparing results obtained by measurement of Tg in the supernate after heparin-manganese chloride (heparin-Mn) precipitation of EDTA-treated plasma (I) with results obtained after preparative ultracentrifugation (II and III). In II, we used heparin-Mn precipitation of low-density lipoprotein (LDL) from the infranate after ultracentrifugation at d 1.006 to remove very-low-density lipoprotein (VLDL). In III, we performed sequential flotation ultracentrifugation at d 1.006 and 1.063, then measured Tg in the d greater than 1.063 fraction. Method I gave significantly higher HDL-Tg results than II and III, which gave essentially identical results. The difference in results between I and II was not caused by the presence of heparin or manganese chloride, because these were used in both methods. Prior removal of VLDL in II and III resulted in lower HDL-Tg values, and subsequent removal of LDL by precipitation or ultracentrifugation did not alter final HDL-Tg values. The higher values obtained in I were the result of the presence of VLDL-rich unsedimented precipitate in the supernate.

Change in composition of high density lipoprotein during gemfibrozil therapy

We investigated the high density lipoprotein cholesterol (HDL-C) response in 20 middle-aged males during a 12-week course of gemfibrozil. Three aspects of the increase in HDL-C (25%) were studied and our observations are as follows: (1) subfraction analysis showed that HDL3-C rose earlier and to a larger extent (28%) than HDL2-C (15%), (2) analysis of variance group--time interaction effect and correlation studies of HDL-C and total triglycerides suggest the increase in HDL-C was due to a direct effect of gemfibrozil on HDL metabolism, and (3) HDL-C was the only one of 4 HDL components to increase. Apoprotein A-I (apo A-I) and HDL-phospholipid (HDL-PL) did not change, and HDL-triglyceride (HDL-TG) decreased. This pattern is consistent with a change in composition of HDL, i.e. cholesterol enrichment and triglyceride depletion.

Changes in serum lipoproteins and high-density lipoprotein composition during isotretinoin therapy

Oral isotretinoin has been reported to increase serum total triglycerides (TG), cholesterol (TC), phospholipids (TPL), apoprotein B (apo B), and to reduce high-density lipoprotein cholesterol (HDL-C). To investigate the effects of isotretinoin on HDL, we measured HDL-C, HDL phospholipids (HDL-PL), apoprotein A1 (apo A-1), and HDL-C subfractions (HDL2-C and HDL3-C) in 24 healthy, male patients receiving a 16-week course of isotretinoin (1.0 mg/kg/day) for treatment of severe acne vulgaris. Patients were placed on a constant diet and fasting lipid parameters were measured every 4 weeks. Analysis of the data from the 20 patients who completed the study confirmed the reported increase in TG, TC, LDL-C, apo B, and LDL-C/HDL-C (all p less than 0.01) observed during isotretinoin therapy. Reduction occurred in HDL-C (p less than 0.05) and HDL2-C (p less than 0.01) while HDL3-C remained unchanged, indicating that the effect of isotretinoin is on the HDL2-C subfraction. Apo A-1 and HDL-PL did not change significantly, suggesting that the reduction in HDL-C represents cholesterol depletion of the HDL particle rather than a reduction in HDL mass. After discontinuing isotretinoin, serum lipid parameters returned to baseline levels.

Rebound elevation of cortisol following cyproheptadine withdrawal in Cushing's disease from a pituitary macroadenoma

A 44-year-old female with Cushing's disease associated with a pituitary macroadenoma was treated with cyproheptadine, 24 mg per day, after partial surgical resection of the tumor. A large residual tumor remained. There was no clear suppression of serum and urinary cortisol during therapy, but both levels rose markedly to beyond pre cyproheptadine levels, on withdrawal of the drug. This is the first report on the use of cyproheptadine in Cushing's disease associated with a pituitary macroadenoma. The response in this patient indicates an influence of cyproheptadine on ACTH secretion by the macroadenoma.

Presence of unsedimented precipitate in visually non-turbid supernates in the heparin-manganese method for HDL-cholesterol quantitation

An inherent problem with the heparin-manganese precipitation procedure for high density lipoprotein-cholesterol (HDL-C) quantitation is the inability to sediment all the precipitated lipoproteins, especially in hypertriglyceridemic samples. This results in overestimation of HDL-C. Thus ultrafiltration has been recommended for turbid supernates. We have investigated 47 non-turbid supernates for possible presence of unsedimented precipitate. Optical turbidity in these samples was found to correlate with the serum triglyceride level. With ultrafiltration of the supernates, there was a significant decrease in cholesterol, optical turbidity and apoprotein A-I. The percent change in turbidity correlated with the percent change in cholesterol. There was also correlation between percent change in cholesterol and the prefiltration supernate turbidity. These results indicate that visually clear supernates may show optical turbidity; the turbidity is likely due to triglyceride-rich particles, which contain cholesterol; the fall in cholesterol with ultrafiltration is due to removal of these floating particles and some adsorbance of HDL particles to the filters.

Hypopituitarism resulting from an intrasellar carotid aneurysm

We report a 74 year old lady who presented with an exceedingly rare combination of an internal carotid artery aneurysm which was almost entirely intrasellar and associated with hypopituitarism but no neurological deficits. Such a lesion could be misdiagnosed as a pituitary tumour with serious consequences, if surgery is attempted without prior carotid angiography.

The effect of cimetidine and ranitidine on serum high density lipoprotein subfractions

Of the two major subfractions of high density lipoprotein (HDL), HDL2 cholesterol (HDL2-C) and not HDL3 cholesterol (HDL3-C) correlates negatively with coronary heart disease. To study the effect of cimetidine and ranitidine on HDL subfractions, 6 healthy males received cimetidine (600 mg bid) ranitidine (150 mg bid) and placebo (one tab bid) for 1 week each, in random order. Measurements of HDL cholesterol (HDL-C), HDL2-C, HDL3-C were made on day 7 of each week. Comparing cimetidine with placebo, HDL2-C/HDL-C, HDL2-C/total cholesterol and HDL2-C/HDL3-C increased significantly while HDL3-C/HDL-C decreased. There was no difference in HDL-C parameters between ranitidine and placebo. Cimetidine treatment results in redistribution of HDL subfractions in favour of HDL2. The mechanism is not H2-receptor antagonism as ranitidine had no such effect.

Inter-laboratory quality control of estrogen and progesterone receptor assays in breast cancer tissue using lyophilised cytosols

In 1981 a quality control (QC) program for estrogen and progesterone receptor assays was organized among six laboratories in Ontario, Canada. Twenty-three vials of lyophilised cytosol prepared from human breast tumor tissues were analysed by each laboratory over a two-year period. Samples of each batch of QC material were analysed at least twice: either in the same batch or on separate occasions. The present study demonstrates the stability of the QC material, defines the relative accuracy of the receptor assays, and provides estimates of within-batch and between-batch precision of the receptor assays.

Cortisol and dexamethasone elimination during treatment with cimetidine

In a randomised cross-over study of treatment for 7 days with cimetidine 600 mg twice daily and placebo, cimetidine had no effect on the pharmacokinetics of a single intravenous dose of dexamethasone sodium phosphate. Likewise the elimination characteristics of endogenous cortisol in the dexamethasone suppressed state were not affected by cimetidine.

The value of urinary chloride measurement in distinguishing surreptitious vomiting from Bartter's syndrome

Urinary chloride measurement is a simple and common procedure but its value in clinical practice is not extensive. This case report highlights a practical and important use of this test. A patient presented with most of the clinical and metabolic derangements of Bartter's syndrome but was found to have extremely low or absent urinary chloride excretion. Her ability to excrete chloride was, however, intact during a chloride load test. The finding of low urinary chloride excretion did not support the diagnosis of Bartter's syndrome and suggested an extrarenal loss of chloride. This was confirmed when she eventually admitted to surreptitious vomiting.

Prostaglandin secretion by human endometrium in vitro

Late proliferative (days 9 to 14) and midsecretory (days 18 to 24) human endometria were maintained in organ culture in the presence of 17 beta-estradiol and/or progesterone or mefenamic acid 17 beta-estradiol (0.1 to 1,000 ng/ml) increased prostaglandin F (PGF) secretion by both proliferative and secretory endometria. Progesterone (1,000 ng/ml) markedly inhibited PGF secretion by proliferative but not secretory endometrium. 17 beta-estradiol and progesterone had no effect on prostaglandin E (PGE) secretion by both types of endometrium. Secretion of both PGF and PGE by proliferative and secretory endometria was inhibited by mefenamic acid ( 1 microgram/ml). This was more apparent with PGF secretion and was detectable within the first 2 hours of culture. These findings indicate that the human endometrium is a rich source of PGF and PGE and that the production of PGF is regulated by gonadal steroids. These results support the concept that one mechanism of action of mefenamic acid in the treatment of dysmenorrhea is inhibition of prostaglandin production.

Salmonella epididymitis with recurrent septicemia in diabetic patient

A diabetic male patient presented with recurrent septicemia due to Salmonella panama. The nidus from which reinfections of the blood stream occurred was apparently localized in the epididymis. Cultures of semen grew Sal. panama while cultures of urine and stool showed no pathogens. This is the fifth reported case of salmonellosis involving epididymis and/or testicle, the first in a diabetic, and the first in which salmonella was found in cultures of semen. In this patient bacteriologic cure was obtained by use of trimethoprim-sulfamethoxazole obviating need for surgical extirpation of the infective focus as had been required in previously reported cases of salmonella epididymitis/orchitis.

Coexisting Paget's disease of bone and hyperparathyroidism

A patient with Paget's disease of bone and primary hyperparathyroidism is described. It has been suggested that a metabolite from pagetic tissue might stimulate parathyroid cell function. To test this, serum parathyroid hormone (iPTH) levels were measured by radio immunometric assay in 106 patients with Paget's disease of bone and 139 control subjects. There was no significant difference between the mean levels of the two groups. Of five sera with elevated PTH levels QUOSO extraction revealed an interfering substance in 3/5 from control patients tested and extractable iPTH in 2/2 from Paget's patients. One of the latter had renal failure. The results suggest that increased parathyroid function is unlikely to be a primary event in the genesis of Paget's disease of bone.

Isolated ACTH deficiency confirmed by ACTH radioimmunoassay

A 28 year old woman presented with symptoms and biochemical findings suggesting hypoglycemia. Detailed endocrine investigations indicated secondary adrenocortical insufficiency with no rise in plasma ACTH or plasma cortisol following insulin-induced hypoglycemia or vasopressin infusion. The adrenal glands however produced cortisol normally following prolonged stimulation with depot tetracosactrin. Other anterior pituitary hormones were released normally following appropriate stimulation tests. The literature on isolated ACTH deficiency is briefly reviewed, and this case represents one of the few reports in which the diagnosis has been substantiated by ACTH radioimmunoassays.