Brown adipose tissue metabolism in women is dependent on ovarian status

In rodents, loss of estradiol (E2) reduces brown adipose tissue (BAT) metabolic activity. Whether E2 impacts BAT activity in women is not known. BAT oxidative metabolism was measured in premenopausal (n = 27; 35 ± 9 yr; body mass index = 26.0 ± 5.3 kg/m2) and postmenopausal (n = 25; 51 ± 8 yr; body mass index = 28.0 ± 5.0 kg/m2) women at room temperature and during acute cold exposure using [11C]acetate with positron emission tomography coupled with computed tomograph. BAT glucose uptake was also measured during acute cold exposure using 2-deoxy-2-[18F]fluoro-d-glucose. To isolate the effects of ovarian hormones from biological aging, measurements were repeated in a subset of premenopausal women (n = 8; 40 ± 4 yr; BMI = 28.0 ± 7.2 kg/m2) after 6 mo of gonadotropin-releasing hormone agonist therapy to suppress ovarian hormones. At room temperature, there was no difference in BAT oxidative metabolism between premenopausal (0.56 ± 0.31 min-1) and postmenopausal women (0.63 ± 0.28 min-1). During cold exposure, BAT oxidative metabolism (1.28 ± 0.85 vs. 0.91 ± 0.63 min-1, P = 0.03) and net BAT glucose uptake (84.4 ± 82.5 vs. 29.7 ± 31.4 nmol·g-1·min-1, P < 0.01) were higher in premenopausal than postmenopausal women. In premenopausal women who underwent gonadotropin-releasing hormone agonist, cold-stimulated BAT oxidative metabolism was reduced to a similar level (from 1.36 ± 0.66 min-1 to 0.91 ± 0.41 min-1) to that observed in postmenopausal women (0.91 ± 0.63 min-1). These results provide the first evidence in humans that reproductive hormones are associated with BAT oxidative metabolism and suggest that BAT may be a target to attenuate age-related reduction in energy expenditure and maintain metabolic health in postmenopausal women.NEW & NOTEWORTHY In rodents, loss of estrogen reduces brown adipose tissue (BAT) activity. Whether this is true in humans is not known. We found that BAT oxidative metabolism and glucose uptake were lower in postmenopausal compared to premenopausal women. In premenopausal women who underwent ovarian suppression to reduce circulating estrogen, BAT oxidative metabolism was reduced to postmenopausal levels. Thus the loss of ovarian function in women leads to a reduction in BAT metabolic activity independent of age.

RF10 | PMON204 Eucaloric High Fat Diet Does Not induce insulin Resistance But May Stimulate Fat Oxidation in Normal Weight Women

Obesity and metabolic syndrome are associated with defects in the hypothalamic pituitary ovarian (HPO) axis termed the reprometabolic syndrome. We have previously shown that lipid infusion induces insulin resistance and the reprometabolic syndrome of obesity in normal weight women. We hypothesized that the induced insulin resistance is the underlying cause of the attenuation of the hypothalamic pituitary ovarian (HPO) axis. 16 women of normal BMI (18-24.9g/m2), mean age 29.7 ± 6.4, were recruited for a study including a 30-day, prescribed, eucaloric, high fat (48% of calories from fat) dietary intervention. Diet was adjusted to ensure that participants remained weight stable throughout the study. Insulin sensitivity was measured by 2 stage euglycemic hyperinsulinemic clamp (8 and 40 mU/m²*min) pre and post diet. Final stage 2 glucoses were not different pre vs post diet (mg/dL, 86±7 vs 89±6, p=0.08). Muscle insulin sensitivity (glucose infusion rate, mg/kg*min) was different pre versus post diet (10.9±3.3 vs 10.6±3.5, p=0.013) after exclusion of one participant for multiple protocol deviations. Adipose insulin sensitivity as measured by fatty acid suppression during the low insulin infusion stage of the clamp was also not different pre versus post diet [final fatty acid level in µEg/L; median 115 (IQR 84, 224) vs 158 (IQR 67,274; p>0.99). However, the final high insulin stage 2 fatty acid suppression trended towards greater suppression after high fat diet [median 17.8 (IQR 9.8,33.8), vs 11.7 (IQR 7.7, 18.7) p=0.06]. This may reflect higher fatty acid oxidation on the high fat diet.

We have previously reported that this diet, like the lipid infusion, did attenuate the HPO axis (reduced baseline early follicular LH and FSH and reduced LH response to GnRH). In contrast to lipid infusion, however, this dietary intervention did not induce the same degree of insulin resistance, possibly due to the emphasis on neutral energy balance, suggesting that the suppression of the HPO axis by high fat diet may be partially independent of insulin sensitivity.

Presentation: Saturday, June 11, 2022 1:24 p.m. - 1:29 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

0599 Sleep duration across the lifespan in type 1 diabetes and association with cardiometabolic risk

Introduction

Individuals with type 1 diabetes (T1D) are at high risk for morbidity and mortality from cardiovascular disease which begins as early as adolescence. Some studies have reported a high prevalence of insufficient sleep in this population which may be due to behavioral and physiological aspects of T1D and its management. Emerging evidence suggests a link between short sleep duration and increased cardiometabolic risk, but this has not been specifically examined across the lifespan in individuals with T1D.

Methods

Inclusion criteria were T1D duration &gt; 9 months, HbA1c 6.5-10% for adults and ≤ 12% for adolescents, and ages 12-60 years. Participants completed home monitoring for one week with continuous glucose monitoring (CGM) and wrist actigraphy prior to a study visit with anthropometric measurements, fasting autonomic/orthostatic and laboratory testing. Peripheral arterial stiffness was measured by Dynapulse brachial artery distensibility (BAD), and insulin sensitivity was estimated by the validated CACTI equation utilizing waist circumference, fasting triglycerides, adiponectin, and diastolic blood pressure. Sleep variables, glycemic markers and health parameters were examined by age group (adolescent vs. adult) using students t-test for univariate comparisons, and linear regression models for age, sex and diabetes duration-adjusted comparisons by age group.

Results

Forty-two adolescents (mean age 16 ± 3 years, diabetes duration 7.4 ± 5 years, HbA1c 8.4 ± 1.1%) and 42 adults (mean age 41 ± 10 years, diabetes duration 21 ± 13 years, HbA1c 7.4 ± 0.9%) completed the study. Sixty-two percent of adolescents and 74% of adults obtained insufficient sleep (&lt; 7 hours of sleep per night). When examined in linear regression adjusted for age group, sex, diabetes duration and age, insufficient sleep was associated with higher BMI (adults), BMI percentile (adolescents), waist circumference, systolic blood pressure, and lower estimated insulin sensitivity and BAD (all p &lt; 0.05).

Conclusion

Most adolescents and adults with T1D obtained insufficient sleep. Objectively-estimated insufficient sleep was associated with worse markers of cardiometabolic risk. Further study examining the impact of sleep health interventions in this population is warranted as sleep may be an important and novel target for improving cardiometabolic health in individuals with T1D.

Support (If Any)

JDRF grant 3-SRA-2015-125-M-R

A randomized clinical trial demonstrating cell type specific effects of hyperlipidemia and hyperinsulinemia on pituitary function

Introduction

Obesity is characterized by elevated lipids, insulin resistance and relative hypogonadotropic hypogonadism, reducing fertility and increasing risk of pregnancy complications and birth defects. We termed this phenotype ‘Reprometabolic Syndrome’ and showed that it can be recapitulated by acute infusions of lipid/insulin into healthy, normal weight, eumenorrheic women. Herein, we examined the broader impact of hyperlipidemia and euglycemic hyperinsulinemia on anterior pituitary trophic hormones and their targets.

Methods

Serum FSH, LH, TSH, growth hormone (GH), prolactin (PRL), thyroid hormones (free T4, total T3), cortisol, IGF-1, adiponectin, leptin and creatinine were measured in a secondary analysis of an interventional crossover study of 12 normal weight cycling women who underwent saline and heparin (control) infusion, or a euglycemic insulin infusion with heparin and Intralipid^® (lipid/insulin), between days 2–5 in sequential menstrual cycles.

Results

In contrast to the decrease in gonadotropins, FSH and LH, infusion of lipid/insulin had no significant effects on other trophic hormones; TSH, PRL or GH. Thyroid hormones (fT4 and total T3), cortisol, IGF-1, adiponectin and creatinine also did not differ between saline or lipid/insulin infusion conditions. Leptin increased in response to lipid/insulin (p<0.02).

Conclusion

Acute hyperlipidemia and hyperinsulinemia exerted differential, cell type specific effects on the hypothalamic-pituitary-gonadal, adrenal and thyroid axes. Elucidation of mechanisms underlying the selective modulation of pituitary trophic hormones, in response to changes in diet and metabolism, may facilitate therapeutic intervention in obesity-related neuroendocrine and reproductive dysfunction.

Heparin Effects on Serum Gonadotropins

Introduction

Studies using lipid infusions to raise fatty acid levels require heparin to release lipoprotein lipase (LPL), thus calling into question the appropriate control infusion for this type of study: saline alone or saline plus heparin. We aimed to evaluate whether the addition of heparin alone, in doses needed to release LPL, would alter circulating free fatty acids (FFAs) and/or affect gonadotropins.

Materials and Methods

This was a secondary analysis using combined data from eumenorrheic normal-weight women subjected to "control" conditions in 1 of 2 separate studies. In 1 study, participants received saline alone (group 1) as a control, and in the other study participants received saline alone and/or saline plus heparin (groups 2-3) as a control. Both studies performed early follicular phase, frequent blood sampling. FSH and LH were compared across groups and in conditions with and without heparin. Linear mixed models were used to analyze the data.

Results

LH did not differ across any of the 3 groups. Estimated means (SE) for FSH differed between groups but this difference was marginal (P = .05) after adjusting for anti-Mullerian hormone and unrelated to heparin infusion (group 1: 4.47 IU/L [SE 1.19], group 2: 8.01 IU/L [SE 1.14], group 3: 7.94 IU/L [SE 1.13]).

Conclusions

Heparin does not exert major effects on gonadotropins when infused in quantities sufficient to release LPL. However, because it can release other vascular membrane-bound proteins, heparin should be considered part of the control infusions in lipid infusion studies where increased FFA levels are the goal.

A randomised trial examining inflammatory signaling in acutely induced hyperinsulinemia and hyperlipidemia in normal weight women-the reprometabolic syndrome

Context

Obesity, is a state of chronic inflammation, characterized by elevated lipids, insulin resistance and relative hypogonadotropic hypogonadism. We have defined the accompanying decreased Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), ovarian steroids and reduced pituitary response to Gonadotropin-releasing Hormone (GnRH) as Reprometabolic syndrome, a phenotype that can be induced in healthy normal weight women (NWW) by acute infusion of free fatty acids and insulin.

Objective

To identify potential mediators of insulin and lipid-related reproductive endocrine dysfunction.

Design, setting, participants

Secondary analysis of crossover study of eumenorrheic reproductive aged women of normal Body Mass Index (BMI) (<25 kg/m²) at an academic medical center.

Intervention

Participants underwent 6-hour infusions of either saline/heparin or insulin plus fatty acids (Intralipid plus heparin), in the early follicular phase of sequential menstrual cycles, in random order. Euglycemia was maintained by glucose infusion. Frequent blood samples were obtained.

Main outcome measures

Pooled serum from each woman was analyzed for cytokines, interleukins, chemokines, adipokines, Fibroblast Growth Factor-21 (FGF-21) and markers of endoplasmic reticulum (ER) stress (CHOP and GRP78). Wilcoxon signed-rank tests were used to compare results across experimental conditions.

Results

Except for Macrophage Inflammatory Protein-1β (MIP-1β), no significant differences were observed in serum levels of any of the inflammatory signaling or ER stress markers tested.

Conclusion

Acute infusion of lipid and insulin, to mimic the metabolic syndrome of obesity, was not associated with an increase in inflammatory markers. These results imply that the endocrine disruption and adverse reproductive outcomes of obesity are not a consequence of the ambient inflammatory environment but may be mediated by direct lipotoxic effects on the hypothalamic-pituitary-ovarian (HPO) axis.

Update on the Acute Effects of Glucose, Insulin, and Incretins on Bone Turnover In Vivo

PURPOSE OF REVIEW

To provide an update on the acute effects of glucose, insulin, and incretins on markers of bone turnover in those with and without diabetes.

RECENT FINDINGS

Bone resorption is suppressed acutely in response to glucose and insulin challenges in both healthy subjects and patients with diabetes. The suppression is stronger with oral glucose compared with intravenous delivery. Stronger responses with oral glucose may be related to incretin effects on insulin secretion or from a direct effect on bone turnover. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) infusion acutely suppresses bone resorption without much effect on bone formation. The bone turnover response to a metabolic challenge may be attenuated in type 2 diabetes, but this is an understudied area. A knowledge gap exists regarding bone turnover responses to a metabolic challenge in type 1 diabetes. The gut-pancreas-bone link is potentially an endocrine axis. This linkage is disrupted in diabetes, but the mechanism and progression of this disruption are not understood.

Mechanistic Causes of Reduced Cardiorespiratory Fitness in Type 2 Diabetes

Type 2 diabetes (T2D) has been rising in prevalence in the United States and worldwide over the past few decades and contributes to significant morbidity and premature mortality, primarily due to cardiovascular disease (CVD). Cardiorespiratory fitness (CRF) is a modifiable cardiovascular (CV) risk factor in the general population and in people with T2D. Young people and adults with T2D have reduced CRF when compared with their peers without T2D who are similarly active and of similar body mass index. Furthermore, the impairment in CRF conferred by T2D is greater in women than in men. Various factors may contribute to this abnormality in people with T2D, including insulin resistance and mitochondrial, vascular, and cardiac dysfunction. As proof of concept that understanding the mediators of impaired CRF in T2D can inform intervention, we previously demonstrated that an insulin sensitizer improved CRF in adults with T2D. This review focuses on how contributing factors influence CRF and why they may be compromised in T2D. Functional exercise capacity is a measure of interrelated systems biology; as such, the contribution of derangement in each of these factors to T2D-mediated impairment in CRF is complex and varied. Therefore, successful approaches to improve CRF in T2D should be multifaceted and individually designed. The current status of this research and future directions are outlined.

Sitagliptin improves diastolic cardiac function but not cardiorespiratory fitness in adults with type 2 diabetes

BACKGROUND

People with type 2 diabetes mellitus (T2D) have preclinical cardiac and vascular dysfunction associated with low cardiorespiratory fitness (CRF). This is especially concerning because CRF is a powerful predictor of cardiovascular mortality, a primary issue in T2D management. Glucagon-like pepetide-1 (GLP-1) augments cardiovascular function and our previous data in rodents demonstrate that potentiating the GLP-1 signal with a dipeptidyl peptidase-4 (DPP4) inhibitor augments CRF. Lacking are pharmacological treatments which can target T2D-specific physiological barriers to exercise to potentially permit adaptations necessary to improve CRF and thereby health outcomes in people with T2D. We therefore hypothesized that administration of a DPP4-inhibitor (sitagliptin) would improve CRF in adults with T2D.

METHODS AND RESULTS

Thirty-eight participants (64 ± 1 years; mean ± SE) with T2D were randomized in a double-blinded study to receive 100 mg/day sitagliptin, 2 mg/day glimepiride, or placebo for 3 months after baseline measurements. Fasting glucose decreased with both glimepiride and sitagliptin compared with placebo (P = 0.002). CRF did not change in any group (Placebo: Pre: 15.4 ± 0.9 vs. Post: 16.1 ± 1.1 ml/kg/min vs. Glimepiride: 18.5 ± 1.0 vs. 17.7 ± 1.2 ml/kg/min vs. Sitagliptin: 19.1 ± 1.2 vs. 18.3 ± 1.1 ml/kg/min; P = 0.3). Sitagliptin improved measures of cardiac diastolic function, however, measures of vascular function did not change with any treatment.

CONCLUSIONS

Three months of sitagliptin improved diastolic cardiac function, however, CRF did not change. These data suggest that targeting the physiological contributors to CRF with sitagliptin alone is not an adequate strategy to improve CRF in people with T2D.

CLINICAL TRIALS REGISTRATION

www.clinicaltrials.gov NCT01951339.

Have rates of erectile dysfunction improved within the past 17 years after radical prostatectomy? A systematic analysis of the control arms of prospective randomized trials on penile rehabilitation

Based on case series, potency rates after radical prostatectomy (RPE) differ substantially and - furthermore - it remains unclear whether they have improved in more recent surgical series. The purpose of this study was to investigate whether potency rates after RPE have improved over the years. A systematic analysis of the control arms of all randomized controlled trials (RCT; n = 11) on penile rehabilitation after RPE was carried out. In total, 2009 patients were included in these RCTs, 685 thereof in the respective control arms, who were either observed or received placebo. Assessment of erectile function in these studies was carried out by the Sexual Encounter Profile (SEP) or the International Index of Erectile Function (IIEF). Eight trials used SEP3 as study endpoint. The rate of positive response to SEP3 (=erectile function sufficient for successful intercourse) in the control arms was 20% in 1997 (year of publication), 10% in 2003, 19% in 2004, 25% in 2008, 21% in 2010, 67% in 2011, 10% in 2013, and 22% in 2014. Eight RCTs assessed the IIEF-EF, yet results were not reported uniformly. In the control arms the IIEF-EF was 9.2 (year of publication 2003), 13.3 (2004), 8.8 (2008), 25% ≥22.0 (2008), 17.4 (2010), 58% ≥26.0 (2011), 9.3 (2013), and 11.6 (2014). Limitations of this analysis are a positive selection bias regarding patient recruitment, surgical approach, and the non-uniform inclusion and outcome criteria. This systematic analysis of the control arms of all RCTs on penile rehabilitation after nerve-sparing RPE shows (i) that the rate of undisturbed erectile function is in the range 20-25% in most studies and (ii) that these rates have not substantially improved or changed over the past 17 years.

European proficiency study with control serum for the tumor marker CA 19-9 measured on different test systems

BACKGROUND

Reliable and precise CA 19-9 testing is required for the long-term follow-up of patients with pancreatic carcinoma during therapy. The aim of this longitudinal proficiency study was to evaluate the comparability, linearity, and precision of CA 19-9 determinations performed in different laboratories using currently available test systems under routine conditions.

METHODS

During the one year study period, 15 laboratories applied 7 different tests and included a liquid BIOREF control serum with pancreatic carcinoma derived CA 19-9 in their routine testing and quality control procedures. The results were collected centrally and evaluated statistically.

RESULTS

The comparability of CA 19-9 results is limited especially when different tests are used, albeit, some tests show a good correlation: The CA 19-9 values obtained by different laboratories using different test systems vary up to a factor of 2. The precision of CA 19-9 determinations was acceptable in most laboratories with coefficients of variation ranging between very low 3.2% and high 17.8%. The imprecision was slightly increased when automatic dilution procedures of the analysers were used.

CONCLUSIONS

The comparability of CA 19-9 test results must be improved. The precision is acceptable in most cases. In order to monitor key performance parameters, every laboratory should participate in external quality assessment schemes and should perform a routine internal quality control with a control serum independent from the test kit manufacturer.

Incidence of balanitis xerotica obliterans in boys younger than 10 years presenting with phimosis

OBJECTIVE

Evaluation of the true incidence of balanitis xerotica obliterans (BXO) among boys younger than 10 years.

METHODS

In a period of 13 months, 75 boys younger than 10 years were treated for phimosis. Suspicion of BXO was raised in phimosis grade 2 or 3 (classification by Kikiros). Patients were offered primarily either circumcision or conservative therapy and circumcision secondarily (if treatment failed in the conservative group). Each circumcision specimen was examined histopathologically.

RESULTS

Circumcision was primarily performed in 29 and secondarily in 17 patients. The mean age was 3.7 years (range 1-10). BXO, chronic inflammation, and normal histological results were found in 8/26/12 (17.4/56.5/26.1%) cases, respectively. The mean follow-up was 8.1 months. No recurrences were reported.

CONCLUSIONS

The incidence of BXO appears to be higher than previously reported. The clinical appearance in children may be confusing. The preoperative BXO suspicion did not correlate with the final histopathological results.

Association of insulin sensitivity to lipids across the lifespan in people with Type 1 diabetes

AIMS

Insulin resistance and dyslipidaemia both increase cardiovascular risk in Type 1 diabetes. However, little data exist on the associations of insulin resistance to lipids in Type 1 diabetes. Our objective was to explore the associations between insulin resistance (assessed by glucose infusion rate) and lipids in people with Type 1 diabetes and determine whether adiposity and/or average glycaemia influence these associations.

METHODS

Hyperinsulinaemic-euglycaemic clamp studies were performed in 60 subjects with Type 1 diabetes aged 12-19 years (age 15±2 years, 57% female, duration of diabetes 6.3±3.8 years, HbA(1c) 8.6±1.5%, IFCC=70 mmol/mol) and 40 subjects with Type 1 diabetes aged 27-61 years (age 45±9 years, 53% female, duration of diabetes 23±8 years, HbA(1c) 7.5±0.9%, IFCC=58 mmol/mol). Multiple linear regression models were fit to examine the association between glucose infusion rate and fasting lipid levels with adjustment for possible confounders.

RESULTS

Lower glucose infusion rate was significantly associated with lower levels of HDL cholesterol in youths with Type 1 diabetes and with higher levels of triglycerides and higher triglyceride/HDL ratio in both youths and adults. The magnitude of the associations between glucose infusion rate and lipid levels translate into interquartile differences of 0.098 mmol/l for HDL cholesterol, 0.17 mmol/l for triglycerides and 1.06 for triglycerides/HDL in the adolescents and 0.20 mmol/l for triglycerides and 1.01 for triglycerides/HDL in the adults. The associations were attenuated and no longer statistically significant by adjustment for adiposity among adults, while adjustment for HbA(1c) had a small effect in youths and adults.

CONCLUSIONS

Lower insulin sensitivity is associated with a more atherogenic lipid profile in both youths and adults with Type 1 diabetes.

Alpha-1-Fetoprotein (AFP): international proficiency study with different test systems

BACKGROUND

The present proficiency study aimed to elucidate the comparability and reliability of test systems for the determination of AFP concentrations.

METHODS

25 laboratories using 8 different commercial test systems used liquid BIOREF-AFP control serum in their routine internal quality control over a period of one year. For statistical analysis the results were collected centrally.

RESULTS

The statistical analysis of the test results revealed considerable variation for the different laboratories. The deviations of the mean values of different laboratories from the overall mean value varied between 0.1 and 26.1%, and for most of the laboratories the deviation was round about 10%. The precision of measured values in the individual laboratories was in most cases acceptable: Nevertheless, the coefficients of variation of the individual laboratories ranged from 13 to 16.1%.

CONCLUSIONS

In conclusion, this study indicates that AFP results vary between different laboratories albeit an international standard for AFP is available. Therefore, every laboratory should participate in external ring studies and should use a quality control serum independent of the test kit manufacturer for the internal quality control.

Precision and long-term stability of different estradiol immunoassays assessed in a multi-center quality control study

BACKGROUND

Because of the vast range of physiological relevant estradiol concentrations the requirements to be met by an estradiol assay are high. In the present study the performance of various commercially available estradiol assays was evaluated with regard to imprecision and long-term stability.

METHODS

Precision and long-term stability of 7 commercially available estradiol immunoassays were assessed in a multi-centre quality control study based on the repeated measurement of liquid BIOREF estradiol control sera by 18 laboratories during a 14-month study period.

RESULTS

The mean estradiol concentrations determined in 594 runs performed for each control level were 71 pg/ml, 349 pg/ml and 676 pg/ml. A high variation was found for the method specific mean values calculated from all results measured with the same method, which ranged between 32 - 90 pg/ml, 187 - 392 pg/ml and 373 - 790 pg/ml, resulting in a similar high inter-laboratory variation with coefficients of variation (CVs) of 25.0%, 16.7% and 17.5%. In contrast, the intra-laboratory variation of estradiol values as well as the variation of values measured with the same method were found to be considerably lower with coefficients of variation < 10% for most laboratories and methods; only the low control level was measured with CV values > 10% by the majority of laboratories and methods. For none of the laboratories a tendency was observed in the results from beginning to end of the 14 month study period indicating a high uniformity in assay production and a good long-term stability of the control material used.

CONCLUSIONS

The present data demonstrate that also with the currently available estradiol immunoassays the comparability of results measured with different methods is limited. With most assays very low estradiol concentrations, as observed in postmenopausal women, can be determined only with a precision which is not adequate for clinical assessment.

Functional behaviour of mononuclear blood cells from patients with hypercholesterolemia

Mononuclear cells were prepared from venous blood obtained from 20 patients with a newly diagnosed hypercholesterolemia and without clinical signs of vascular disease, and from 19 age and sex matched controls. Adhesiveness to plastic surface, phagocytic activity measured as ingestion of zymosan particles, and spontaneous motility of mononuclear cells from patients were significantly higher by 57%, 19% and 50%, respectively, when compared to controls. In controls chemotaxis induced by the chemotactic peptide FMLP was slightly higher than spontaneous motility measured in absence of FMLP, whereas in patients FMLP significantly inhibited cell motility by about 47%. With the exception of FMLP-induced chemotaxis the results indicate that mononuclear cells are hyperreactive in hypercholesterolemia.

[Lipoprotein metabolism and beta receptor blockers]

Including own results a survey is given of the side effects of beta-receptor blockers on the plasma lipoprotein metabolism. The formation of a from the coronary-preventive point of view unfavourable lipoprotein risk profile under influence of individual beta-receptor blockers, among others propranolol, seems to be connected with an inhibition of a key enzyme in the lipoprotein metabolism, the lecithin-cholesterol-acyl transferase. Talinolol does not show these side effects. It is recommended to control the triglyceride level and the HDL cholesterol before the induction and after the beginning of a therapy with beta-receptor blockers and to use talinolol instead of propranolol in pre-existing dyslipoproteinaemia or in unfavourable changes during the treatment.

Invertase signal and mature sequence substitutions that delay intercompartmental transport of active enzyme

The role of structural signals in intercompartmental transport has been addressed by the isolation of yeast invertase (SUC2) mutations that cause intracellular accumulation of active enzyme. Two mutations that delay transport of core-glycosylated invertase, but not acid phosphatase, have been mapped in the 5' coding region of SUC2. Both mutations reduce specifically the transport of invertase to a compartment, presumably in the Golgi body, where outer chain carbohydrate is added. Subsequent transport to the cell surface is not similarly delayed. One mutation (SUC2-s1) converts an ala codon to val at position -1 in the signal peptide; the other (SUC2-s2) changes a thr to an ile at position +64 in the mature protein. Mutation s1 results in about a 50-fold reduced rate of invertase transport to the Golgi body which is attributable to defective signal peptide cleavage. While peptide cleavage normally occurs at an ala-ser bond, the s1 mutant form is processed slowly at the adjacent ser-met position giving rise to mature invertase with an N-terminal met residue. s2 mutant invertase is transported about sevenfold more slowly than normal, with no delay in signal peptide cleavage, and no detectable abnormal physical property of the enzyme. This substitution may interfere with the interaction of invertase and a receptor that facilitates transport to the Golgi body.

Effect of talinolol and the optical isomers of propranolol on LCAT activity in vitro

In vitro effects of DL-propranolol (a therapeutically used beta-blocker with local anesthetic properties), L-propranolol (having both beta-blocking and unspecific local anesthetic properties), D-propranolol (having local anesthetic, but much less beta-blocking properties), and talinolol (a therapeutically used beta-1-blocker with much less local anesthetic properties) on lecithin: cholesterol acyl transferase (LCAT) activity in human plasma were compared. Both D-propranolol and L-propranolol inhibited LCAT activity, the former being a little more effective. The racemic mixture showed intermediate dose-effect curves. In no case could a complete inhibition be achieved. Talinolol exhibited no effect on LCAT activity. Therefore, the inhibition of LCAT activity by beta-blocking drugs may be connected with their local anesthetic properties. Because LCAT inhibition is followed by a decrease of HDL cholesterol and an increase of triglycerides in plasma, it is recommended to use only beta-blockers without such side effects on lipoprotein metabolism for therapeutical purposes.

Invertase beta-galactosidase hybrid proteins fail to be transported from the endoplasmic reticulum in Saccharomyces cerevisiae

The yeast SUC2 gene codes for the secreted enzyme invertase. A series of 16 different-sized gene fusions have been constructed between this yeast gene and the Escherichia coli lacZ gene, which codes for the cytoplasmic enzyme beta-galactosidase. Various amounts of SUC2 NH2-terminal coding sequence have been fused in frame to a constant COOH-terminal coding segment of the lacZ gene, resulting in the synthesis of hybrid invertase-beta-galactosidase proteins in Saccharomyces cerevisiae. The hybrid proteins exhibit beta-galactosidase activity, and they are recognized specifically by antisera directed against either invertase or beta-galactosidase. Expression of beta-galactosidase activity is regulated in a manner similar to that observed for invertase activity expressed from a wild-type SUC2 gene: repressed in high-glucose medium and derepressed in low-glucose medium. Unlike wild-type invertase, however, the invertase-beta-galactosidase hybrid proteins are not secreted. Rather, they appear to remain trapped at a very early stage of secretory protein transit: insertion into the endoplasmic reticulum (ER). The hybrid proteins appear only to have undergone core glycosylation, an ER process, and do not receive the additional glycosyl modifications that take place in the Golgi complex. Even those hybrid proteins containing only a short segment of invertase sequences at the NH2 terminus are glycosylated, suggesting that no extensive folding of the invertase polypeptide is required before initiation of transmembrane transfer. beta-Galactosidase activity expressed by the SUC2-lacZ gene fusions cofractionates on Percoll density gradients with ER marker enzymes and not with other organelles. In addition, the hybrid proteins are not accessible to cell-surface labeling by 125I. Accumulation of the invertase-beta-galactosidase hybrid proteins within the ER does not appear to confer a growth-defective phenotype to yeast cells. In this location, however, the hybrid proteins and the beta-galactosidase activity they exhibit could provide a useful biochemical tag for yeast ER membranes.

Genes required for completion of import of proteins into the endoplasmic reticulum in yeast

Yeast secretory mutants sec53 and sec59 define a posttranslational stage in the penetration of glycoprotein precursors into the endoplasmic reticulum (ER). In the previous report we showed that at the restrictive temperature (37 degrees C) these mutants accumulate enzymatically inactive and incompletely glycosylated forms of the secretory enzyme invertase and the vacuolar enzyme carboxypeptidase Y. Cell fractionation experiments reveal that these precursor forms remain firmly bound to the ER membrane. However, upon return to the permissive temperature (24 degrees C), the invertase precursors are glycosylated, become partially active, and are secreted. Thermoreversible conversion does not require protein synthesis, but does require energy. In contrast to the effect of these mutations, inhibition of oligosaccharide synthesis with tunicamycin at 37 degrees C causes irreversible accumulation of unglycosylated invertase. The effect of the drug is exaggerated by high temperature since unglycosylated invertase synthesized in the presence of tunicamycin at 25 degrees C is secreted. A portion of the invertase polypeptide accumulated at 37 degrees C is preserved when membranes from sec53 and sec59 are treated with trypsin. In the presence of Triton X-100 or saponin, the invertase is degraded completely. The protected fragment appears to represent a portion of the invertase polypeptide that is embedded in or firmly associated with the ER membrane. This association may develop early during the synthesis of invertase, so that in the absence of translocation, some of the completed polypeptide chain remains exposed on the cytoplasmic surface of the ER.

[Effectiveness of different intervention measures in children and adolescents with hypertension and lipid metabolism disorders]

141 children and adolescents (7-21 years, mean age 14.2 years) showed values of blood pressure, total cholesterol and triglycerides greater than or equal to 90 percentile and HDL-cholesterol values less than or equal to 10 during an examination of 639 children of parents with distinct coronary risk factors or early percentile infarction. By randomization they were subdivided into two groups. (A and B) and underwent intervention measures of different intensity. While group B got only a unique recommendation concerning the preventive measures, in group A a regular, non medicamentous individual treatment was performed. After one year a decrease of blood pressure could be proved in the two groups. A significant decrease of total and HDL cholesterol was found only in group A. While the blood pressure was most clearly reduced in 7-13-year-old children, the most distinct lipid changes were shown in 14-17-year-old adolescents. An influence on body-weight and triglycerides could not be established. Our results confirm the possibilities and also the limits of preventive measures in childhood and adolescence. Apart from the intended decrease of blood pressure and total cholesterol the simultaneous decrease of HDL-cholesterol refers to open questions in the conception of the primary prevention, particularly in children.

[Physical training following myocardial infarct complicated by ventricular fibrillation]

Case histories of 4 patients with myocardial infarction are given, 3 had ventricular fibrillation during the acute period and one a month later after infarction. When discharged all of them completed a physical training program. They had no rhythm disorders and all returned to work. It is concluded that myocardial infarction cases who had had ventricular fibrillation can achieve complete rehabilitation, if there are no rhythm disorders during exercise. Physical training can be used for rehabilitation.

Use of the microanalytical system KAPA for serial determinations of triglycerides, total cholesterol and HDL cholesterol in capillary plasma

Enzymatic methods adapted to the KAPA system can be carried out in a final test volume of less than 10 mu 1. The procedure is mechanized, including the pre-analytical steps. Day-to-day precision is 2-6% C.V. for single determinations. Advantages of the technique are: (1) capillary plasma can be used; (2) reagent waste is reduced by about two orders of magnitude compared to common procedures, and (3) 400 specimens can be assayed by one technician per day. These conditions facilitate serial determinations, large scale screening, or repetitive monitoring of values in a group of individuals.

[The correlation of blood pressure, cholesterol and triglyceride concentration with the administration of hormonal contraceptives in women from 2 Erfurt large-scale plants]

Within the framework of medical check-ups of heart and circulatory system 1,296 women at the age from 15 to 49 years were examined in two Erfurt large plants. Women with hormonal contraception in the age groups 30-34, 35-39 and 45-49 showed statistically significantly higher mean values of the systolic blood pressure than women without oral contraception. In the same way the difference of the cholesterol mean value of 15.3 mg/100 ml and 11 mg/100 ml depending on the intake of ovulation inhibitors could be statistically ascertained in women at the age of 20-24 and 30-34 years. Women with hormonal contraception have statistically significantly higher triglyceride mean value in the age group 15-24 and 35-44 years than the women without oral contraception.

[Prerequisites for the physical training of patients who have had a myocardial infarct (substantiation, functional diagnosis, indications, contraindications)]

The substantiation and the indications and contraindications for the physical training of patients who have had myocardial infarction are discussed on the basis of the experience gained at the Clinic of Internal Diseases of the Medical Department of K. Marx University in Leipzig (DDR) and the First Chair of Hospital Therapy of the N.I. Pirogov Second Moscow Medical Institute. On the strength of their own findings and the information in the current literature, the authors name, among other precoditions for training, diminution of capacity for muscular work, psychologic instability and the persisting threat of the progression of ischemic heart disease. The methods of functional diagnosis, which is also a necessary precondition for the physical rehabilitation of the patients are bicycle ergometry, auxiliary tests for the gaseous composition of blood and exhaled air, determination of the heart volume by means of X-ray, catheterization of the pulmonary artery with a floating catheter, ventriculography, and coronarography.