My Baby's Movements: a stepped-wedge cluster-randomised controlled trial of a fetal movement awareness intervention to reduce stillbirths.

OBJECTIVE: The My Baby's Movements (MBM) trial aimed to evaluate the impact on stillbirth rates of a multifaceted awareness package (the MBM intervention). DESIGN: Stepped-wedge cluster-randomised controlled trial. SETTING: Twenty-seven maternity hospitals in Australia and New Zealand. POPULATION: Women with a singleton pregnancy without major fetal anomaly at ≥28 weeks of gestation from August 2016 to May 2019. METHODS: The MBM intervention was implemented at randomly assigned time points, with the sequential introduction of eight groups of between three and five hospitals at 4-monthly intervals. Using generalised linear mixed models, the stillbirth rate was compared in the control and the intervention periods, adjusting for calendar time, study population characteristics and hospital effects. MAIN OUTCOME MEASURES: Stillbirth at ≥28 weeks of gestation. RESULTS: There were 304 850 births with 290 105 births meeting the inclusion criteria: 150 053 in the control and 140 052 in the intervention periods. The stillbirth rate was lower (although not statistically significantly so) during the intervention compared with the control period (2.2/1000 versus 2.4/1000 births; aOR 1.18, 95% CI 0.93-1.50; P = 0.18). The decrease in stillbirth rate was greater across calendar time: 2.7/1000 in the first versus 2.0/1000 in the last 18 months. No increase in secondary outcomes, including obstetric intervention or adverse neonatal outcome, was evident. CONCLUSIONS: The MBM intervention did not reduce stillbirths beyond the downward trend over time. As a result of low uptake, the role of the intervention remains unclear, although the downward trend across time suggests some benefit in lowering the stillbirth rate. In this study setting, an awareness of the importance of fetal movements may have reached pregnant women and clinicians prior to the implementation of the intervention. TWEETABLE ABSTRACT: The My Baby's Movements intervention to raise awareness of decreased fetal movement did not significantly reduce stillbirth rates.

My Baby's Movements: a stepped wedge cluster randomised controlled trial to raise maternal awareness of fetal movements during pregnancy study protocol.

BACKGROUND: Stillbirth is a devastating pregnancy outcome that has a profound and lasting impact on women and families. Globally, there are over 2.6 million stillbirths annually and progress in reducing these deaths has been slow. Maternal perception of decreased fetal movements (DFM) is strongly associated with stillbirth. However, maternal awareness of DFM and clinical management of women reporting DFM is often suboptimal. The My Baby's Movements trial aims to evaluate an intervention package for maternity services including a mobile phone application for women and clinician education (MBM intervention) in reducing late gestation stillbirth rates. METHODS/DESIGN: This is a stepped wedge cluster randomised controlled trial with sequential introduction of the MBM intervention to 8 groups of 3-5 hospitals at four-monthly intervals over 3 years. The target population is women with a singleton pregnancy, without lethal fetal abnormality, attending for antenatal care and clinicians providing maternity care at 26 maternity services in Australia and New Zealand. The primary outcome is stillbirth from 28 weeks' gestation. Secondary outcomes address: a) neonatal morbidity and mortality; b) maternal psychosocial outcomes and health-seeking behaviour; c) health services utilisation; d) women's and clinicians' knowledge of fetal movements; and e) cost. 256,700 births (average of 3170 per hospital) will detect a 30% reduction in stillbirth rates from 3/1000 births to 2/1000 births, assuming a significance level of 5%. Analysis will utilise generalised linear mixed models. DISCUSSION: Maternal perception of DFM is a marker of an at-risk pregnancy and commonly precedes a stillbirth. MBM offers a simple, inexpensive resource to reduce the number of stillborn babies, and families suffering the distressing consequences of such a loss. This large pragmatic trial will provide evidence on benefits and potential harms of raising awareness of DFM using a mobile phone app. TRIAL REGISTRATION: ACTRN12614000291684. Registered 19 March 2014. VERSION: Protocol Version 6.1, February 2018.

Abundant LacZ activity in the absence of Cre expression in the normal and inflamed synovium of adult Col2a1-Cre; ROSA26RLacZ reporter mice.

Recent analyses of Col2a1-Cre; ROSA26R reporter mice showed that synovial fibroblasts in 7-day mice were LacZ positive, due to a history of Col2a1-Cre expression conferred by their origin in the interzone of the developing joint. We have examined LacZ staining in adult Col2a1-Cre(+/0); ROSA26R(LacZ) mice, with and without inflammatory arthritis, and found that synovial fibroblasts in normal and inflamed synovium are LacZ positive, but Cre negative. Our results suggest that Cre-mediated recombination in joint interzone cells during development endure in adult synovial cells despite the absence of ongoing Cre expression. These findings have important implications and applications for the study of synovial inflammation in models of experimental arthritis.

A gene map of the human genome.

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

ADAMTS-5: the story so far.

The recent discovery of ADAMTS-5 as the major aggrecanase in mouse cartilage came as a surprise. A great deal of research had focused on ADAMTS-4 and much less was known about the regulation, expression and activity of ADAMTS-5. Two years on, it is still not clear whether ADAMTS-4 or ADAMTS-5 is the major aggrecanase in human cartilage. On the one hand there are in vitro studies using siRNA, neutralising antibodies and immunoprecipitation with anti-ADAMTS antibodies that suggest a significant role for ADAMTS-4 in aggrecanolysis. On the other hand, ADAMTS-5 (but not ADAMTS-4)-deficient mice are protected from cartilage erosion in models of experimental arthritis, and recombinant human ADAMTS-5 is substantially more active than ADAMTS-4. The activity of both enzymes is modulated by C-terminal processing, which occurs naturally in vivo. The most interesting finding to emerge from our comparison of ADAMTS-5 and ADAMTS-4 is that in terms of gene regulation, these two enzymes are the antitheses of each other. In most cases, ADAMTS-5 is constitutively expressed in human chondrocytes and synovial fibroblasts, whereas ADAMTS-4 expression is induced by proinflammatory cytokines. This paper reviews the data on ADAMTS-5 so far. It represents a snapshot in time of a field that is fast-moving and very exciting.

Demonstration of 26-hydroxylation of C27-steroids in human skin fibroblasts, and a deficiency of this activity in cerebrotendinous xanthomatosis.

26-Hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol and other C27-steroids was demonstrated in cultured skin fibroblasts from healthy individuals. Activities in skin fibroblasts were approximately 5-10% of those previously found in human liver homogenates, and were inhibited by CO. The apparent Km was lowest for 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol (1.3 mumol/liter) and highest for 5-cholestene-3 beta, 7 alpha-diol (12 mumol/liter). The rate of 26-hydroxylation was highest with 7 alpha-hydroxy-4-cholesten-3-one. These characteristics are similar to those of hepatic mitochondrial C27-steroid 26-hydroxylase. In skin fibroblasts from three patients with cerebrotendinous xanthomatosis (CTX), 26-hydroxylation of C27-steroids proceeded at a rate of only 0.2-2.5% of healthy controls. No accumulation of endogenous 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol could be demonstrated in these cells, and the lowered formation of radioactive, 26-hydroxylated products could not be explained by dilution of the labeled exogenous substrate. The present results add strong evidence to the concept that the primary metabolic defect in CTX is a deficiency of C27-steroid 26-hydroxylase.

Uptake of cholesterol-rich remnant lipoproteins by human monocyte-derived macrophages is mediated by low density lipoprotein receptors.

The uptake and degradation of cholesterol-rich remnant lipoproteins, referred to as beta-VLDL, are shown in the present study to be mediated by LDL receptors (apoB,E(LDL) receptors), not by unique beta-VLDL receptors. Human blood monocytes cultured for 5-7 d bound apoB- and/or apoE-containing lipoproteins from different species with affinities equivalent to those demonstrated for the receptors on cultured human fibroblasts. Low density lipoproteins competed effectively and completely with 125I-beta-VLDL for binding to and degradation by monocyte-derived macrophages. Specific polyclonal antibodies to bovine apoB,E(LDL) receptors abolished both LDL and beta-VLDL uptake by normal human monocyte-macrophages. Immunoblots of monocyte-macrophage extracts with these antibodies revealed a single protein in human macrophages with an apparent molecular weight identical to that of the apoB,E(LDL) receptor found on human fibroblasts. Like receptors on cultured human fibroblasts, the apoB,E(LDL) receptors on monocyte-macrophages responsible for 125I-beta-VLDL and 125I-LDL uptake were efficiently down regulated by preincubation of the cells with beta-VLDL or LDL. Finally, monocyte-macrophages from seven homozygous familial hypercholesterolemia subjects were unable to metabolize beta-VLDL or LDL, but demonstrated normal uptake of acetoacetylated LDL. The classic apoB,E(LDL) receptors on human monocyte-macrophages thus mediate the uptake of beta-VLDL by these cells.

Fetal pulse oximetry for fetal assessment in labour.

BACKGROUND: Pulse oximetry could contribute to the evaluation of fetal well-being during labour. OBJECTIVES: To compare the effectiveness and safety of fetal pulse oximetry with conventional surveillance techniques. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (November 2006), MEDLINE (1994 to November 2006), EMBASE (1994 to November 2006) and Current Contents (1994 to November 2006). SELECTION CRITERIA: All published and unpublished randomised controlled trials that compared maternal and fetal outcomes when fetal pulse oximetry was used in labour, with or without concurrent use of conventional fetal surveillance, compared with using cardiotocography (CTG) alone. DATA COLLECTION AND ANALYSIS: At least two independent authors performed data extraction. Analyses were performed on an intention-to-treat basis. We sought additional information from the investigators of three of the reported trials. MAIN RESULTS: Five published trials comparing fetal pulse oximetry and CTG with CTG alone (or when fetal pulse oximetry values were blinded) were included. The published trials, with some unpublished data, reported on a total of 7424 pregnancies. Differing entry criteria necessitated separate analyses, rather than meta-analysis of all trials. Four trials reported no significant differences in the overall caesarean section rate between those monitored with fetal oximetry and those not monitored with fetal pulse oximetry or for whom the fetal pulse oximetry results were masked. Neonatal seizures and hypoxic ischemic encephalopathy were rare. No studies reported details of assessment of long-term disability. There was a statistically significant decrease in caesarean section for nonreassuring fetal status in the fetal pulse oximetry plus CTG group compared to the CTG group in two analyses: (i) gestation from 36 weeks with fetal blood sample (fetal blood sampling) not required prior to study entry (relative risk (RR) 0.68, 95% confidence interval (CI) 0.47 to 0.99); and (ii) when fetal blood sampling was required prior to study entry (RR 0.03, 95% CI 0.00 to 0.44). There was no statistically significant difference in caesarean section for dystocia when fetal pulse oximetry (fetal pulse oximetry) was added to CTG monitoring, compared with CTG monitoring alone, although the incidence rates varied between the trials. AUTHORS' CONCLUSIONS: The data provide limited support for the use of fetal pulse oximetry when used in the presence of a nonreassuring CTG, to reduce caesarean section for nonreassuring fetal status. The addition of fetal pulse oximetry does not reduce overall caesarean section rates. A better method to evaluate fetal well-being in labour is required.

Local cooling for relieving pain from perineal trauma sustained during childbirth.

BACKGROUND: Perineal trauma is common during childbirth and may be painful. Contemporary maternity practice includes offering women numerous forms of pain relief, including the local application of cooling treatments. OBJECTIVES: To evaluate the effectiveness and side effects of localised cooling treatments compared with no treatment, other forms of cooling treatments and non-cooling treatments. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2007), CINAHL (1982 to January 2007) and contacted experts in the field. SELECTION CRITERIA: Published and unpublished randomised and quasi-randomised trials (RCTs) that compared localised cooling treatment applied to the perineum with no treatment or other treatments applied to relieve pain related to perineal trauma sustained during childbirth. DATA COLLECTION AND ANALYSIS: At least two independent authors performed data extraction for each study. Analyses were performed on an intention-to-treat basis where data allowed. We sought additional information from the authors of three trials. MAIN RESULTS: Seven published RCTs were included, comparing local cooling treatments (ice packs, cold gel pads or cold/iced baths) with no treatment, hamamelis water (witch hazel), pulsed electromagnetic energy (PET), hydrocortisone/pramoxine foam [Epifoam] or warm baths. The RCTs reported on a total of 859 women. Ice packs provided improved pain relief 24 to 72 hours after birth compared with no treatment (risk ratio (RR) 0.61, 95% confidence interval (CI) 0.41 to 0.91). Women preferred the utility of the gel pads compared with ice packs or no treatment, although no differences in pain relief were detected between the treatments. None of our comparisons of treatments resulted in differences detected in perineal oedema or bruising. Women reported more pain (RR 5.60, 95% CI 2.35 to 13.33) and used more additional analgesia (RR 4.00, 95% CI 1.44 to 11.13) following the application of ice packs compared with PET. AUTHORS' CONCLUSIONS: There is only limited evidence to support the effectiveness of local cooling treatments (ice packs, cold gel pads, cold/iced baths) applied to the perineum following childbirth to relieve pain.

Prophylactic vs postoperative antibiotic use in complex septorhinoplasty surgery: a prospective, randomized, single-blind trial comparing efficacy.

OBJECTIVE: To compare the efficacy of prophylactic vs postoperative antibiotic use in complex septorhinoplasty and strengthen the evidence base for antibiotic use in nasal surgery. DESIGN: A randomized, prospective, single-blinded trial. One hundred sixty-four patients requiring complex septorhinoplasty surgery were recruited sequentially from the waiting lists of the 2 senior authors. Power was calculated at 80% at the 5% significance level. Patients randomized to the prophylactic arm of the study received three 1200-mg intravenous doses of amoxicillin-clavulanate, given at induction of anesthesia and at 6 and 12 hours postoperatively. Patients in the postoperative antibiotic arm received a 7-day course of 375 mg of amoxicillin-clavulanate 3 times a day. Patients allergic to penicillin were given erythromycin. Clinical and microbiological evidence of infection on the 10th postoperative day was categorized as either minor (vestibulitis) or major (nasal or septal cellulitis, septal abscess, secondary hemorrhage, or donor-site infection) infections. RESULTS: At follow-up, 6 (7%) of 82 patients in the prophylactic arm and 9 (11%) of 82 of patients in the postoperative arm showed evidence of infection. Most (80%) of infections were minor. There was no significant difference in infection rates between the prophylactic and postoperative arms on chi2 analysis (P = .42). All 164 patients completed the study on an intention-to-treat basis. CONCLUSION: We recommend the use of prophylactic antibiotics rather than empirical postoperative antibiotics for patients undergoing complex septorhinoplasty.

Tumor progression of murine epidermal cells after treatment in vitro with 12-O-tetradecanoylphorbol-13-acetate or retinoic acid.

Tumor-promoting or antipromoting agents potentially may act directly on initiated squamous epithelial cells or indirectly through effects on normal keratinocytes or immune cells. The purpose of this study was to examine direct effects by comparing in vitro and in vivo treatment of initiated cell populations with 12-O-tetradecanoylphorbol-13-acetate (TPA) or retinoic acid. Keratinocytes were initiated by treatment in vitro with 7,12-dimethylbenz[alpha]anthracene. Replicate cultures of a cloned initiated cell line were exposed to TPA or retinoic acid with acetone as control. After an equivalent number of population doublings, cultured cell sheets were transplanted as skin grafts to athymic nude mice. Replicate grafts from each in vitro treatment group were then treated with TPA or retinoic acid for 8 months. Promotion was quantified by tumor incidence (graft sites with tumor per total sites) and by tumor growth rate. The findings were as follows: (a) TPA increased tumor incidence whether it was applied in vitro or in vivo; (b) TPA in vitro favored more progressive tumors than TPA in vivo; (c) stages of malignant progression from cloned keratinocytes treated in vitro were histologically identical to those following treatment of skin in vivo, including papilloma, dysplastic invasive papilloma, squamous cell carcinoma, and metastasis to lymph node and lung; (d) retinoic acid treatment in vivo reduced tumor incidence and tumor growth rate in initiated cells previously exposed to TPA but not in cells previously exposed to retinoic acid. The results indicated the following: (a) direct effects of TPA on initiated keratinocyte populations were a significant component of tumor promotion; (b) factors in vivo modified the TPA response toward less progressive growth; and (c) the effect of retinoic acid was modulated by prior treatment history.

Influence of baseline lipids on effectiveness of pravastatin in the CARE Trial. Cholesterol And Recurrent Events.

OBJECTIVES: We sought to assess the influence of baseline lipid levels on coronary event rates and the effectiveness of pravastatin therapy in the Cholesterol And Recurrent Events (CARE) study. BACKGROUND: The CARE study cohort provided a relatively unique opportunity to examine the relation between lipid levels and clinical events in a post-myocardial infarction (MI) population with relatively low cholesterol and low density lipoprotein (LDL) cholesterol values. METHODS: There were 4,159 patients with a previous infarct and a total cholesterol level <240 mg/dl, LDL cholesterol level 115 to 174 mg/dl and triglyceride level <350 mg/dl randomly allocated to placebo (n=2,078) or pravastatin 40 mg/day (n=2,081). Time to either coronary death or nonfatal MI (primary end point) or to the secondary end point, which included undergoing a coronary revascularization procedure, was determined as a function of baseline lipids (total, LDL, high density lipoprotein [HDL] cholesterol and triglyceride levels). RESULTS: Quartile analysis indicated important effects for LDL cholesterol, in which a higher LDL was associated with greater cardiac event rates (in the placebo group, every 25-mg/dl increment in LDL was associated with a 28% increased risk [5% to 56%, p=0.015]) in the primary event. The differential event rates with respect to baseline LDL cholesterol for placebo and pravastatin groups reduced the difference in clinical outcomes at lower LDL cholesterol levels. In both the placebo and pravastatin groups, an inverse relation between baseline HDL cholesterol and cardiac events was observed (10 mg/dl lower baseline HDL cholesterol level was associated with a 10% [0% to 19%, p=0.046] increase in coronary death or nonfatal MI). CONCLUSIONS: Within the LDL cholesterol levels in CARE (115 to 174 mg/dl), baseline values influenced both the risk of events in the placebo group as well as the clinical effectiveness of pravastatin therapy.

Effect of pravastatin on cardiovascular events in women after myocardial infarction: the cholesterol and recurrent events (CARE) trial.

OBJECTIVES: We sought to determine the effect of pravastatin on recurrent cardiovascular events in women with average cholesterol levels after myocardial infarction (MI). BACKGROUND: Little information is available on the effectiveness of lipid lowering in secondary prevention of coronary heart disease (CHD) in women; in particular, those with CHD and average cholesterol levels. METHODS: In the Cholesterol and Recurrent Events (CARE) trial, 576 postmenopausal women, between 3 and 20 months after MI, with a total cholesterol level <240 mg/dl and a low density lipoprotein cholesterol level 115 to 174 mg/dl, were randomized to receive pravastatin 40 mg/day or matching placebo for a median follow-up period of 5 years. The main outcome measures were combined coronary events (coronary death, nonfatal MI, percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft surgery [CABG]), the primary trial end point (coronary death or nonfatal MI) and stroke. RESULTS: Women treated with pravastatin had a risk reduction of 43% for the primary end point (p = 0.035), 46% for combined coronary events (p = 0.001), 48% for PTCA (p = 0.025), 40% for CABG (p = 0.14) and 56% for stroke (p = 0.07). The 3,583 men in the CARE trial also showed a reduction in risk, but the magnitude tended to be less. Pravastatin improved plasma lipids similarly in men and women. There were no differences in risk of coronary events in the placebo group between men and women. Minor differences between men and women were present in baseline characteristics and treatment for MI, in general, conferring a higher risk status and a lower incidence of CABG in the women. CONCLUSIONS: Pravastatin led to significant early reduction of a wide range of cardiovascular events in post-MI women with average cholesterol levels.

Vibroacoustic stimulation for fetal assessment in labour in the presence of a nonreassuring fetal heart rate trace.

BACKGROUND: Fetal vibroacoustic stimulation is a simple, non-invasive technique where a device is placed on the maternal abdomen over the region of the fetal head and sound is emitted at a predetermined level for several seconds. It is hypothesized that the resultant startle reflex in the fetus and subsequent fetal heart rate acceleration or transient tachycardia following vibroacoustic stimulation provide reassurance of fetal well-being. This technique has been proposed as a tool to assess fetal well-being in the presence of a non-reassuring cardiotocographic trace during the first and second stages of labour. OBJECTIVES: To evaluate the clinical effectiveness and safety of vibroacoustic stimulation in the assessment of fetal well-being during labour, compared with mock or no stimulation for women with a singleton pregnancy exhibiting a non-reassuring fetal heart rate pattern. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 September 2004), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2004), MEDLINE (January 1966 to January 2005), EMBASE (January 1966 to January 2005) and reference lists of all retrieved articles. We sought unpublished trials and abstracts submitted to major international congresses and contacted expert informants. SELECTION CRITERIA: All published and unpublished randomised trials that compared maternal and fetal/neonatal/infant outcomes when vibroacoustic stimulation was used to evaluate fetal status in the presence of a non-reassuring cardiotocographic trace during labour, compared with mock or no stimulation. DATA COLLECTION AND ANALYSIS: Two independent review authors identified potential studies from the literature search and assessed them for methodological quality and appropriateness of inclusion, using a data extraction form. Attempts to contact study authors for additional information were unsuccessful. MAIN RESULTS: The search strategies yielded six studies for consideration of inclusion. However, none of these studies fulfilled the requirements for inclusion in this review. AUTHORS' CONCLUSIONS: There are currently no randomised controlled trials that address the safety and efficacy of vibroacoustic stimulation used to assess fetal well-being in labour in the presence of a non-reassuring cardiotocographic trace. Although vibroacoustic stimulation has been proposed as a simple, non-invasive tool for assessment of fetal well-being, there is insufficient evidence from randomised trials on which to base recommendations for use of vibroacoustic stimulation in the evaluation of fetal well-being in labour in the presence of a non-reassuring cardiotocographic trace.

Risk stratification in early pregnancy for women at increased risk of gestational diabetes.

AIM: To evaluate the addition of fasting glucose and lipids to a simple, validated risk prediction tool for gestational diabetes (GDM) applied in early pregnancy. METHODS: Women at risk of developing GDM on a validated risk prediction tool were recruited in early pregnancy into a large randomised controlled trial. Outcome measures included fasting biochemical markers (glucose, lipids) at 12-15 weeks gestation and GDM diagnosis (28 weeks gestation). Multivariable logistic regression was used to identify additional predictive biochemical variables for GDM, with corresponding receiver operator characteristic (ROC) curves generated. Unadjusted and adjusted models were derived for both the Australasian Diabetes in Pregnancy (ADIPS) and the International Association for Diabetes in Pregnancy Study Group (IADPSG) GDM diagnostic criteria. RESULTS: 51 (23%) Women were diagnosed with GDM based on ADIPS criteria, with 60 (30%) diagnosed based on IADPSG criteria. In all four regression models, fasting glucose was the strongest predictor for GDM development with an odds ratio range of 4.7-6.3 (ADIPS) and 8.8-10 (IADPSG). ROC curves revealed an area under the curve of 0.79 (95% CI: 0.72-0.86) for ADIPS criteria and 0.83 (95% CI: 0.77-0.90) for IADPSG criteria for adjusted models. CONCLUSIONS: In a two-step approach, when applied with a validated risk prediction tool, fasting glucose in early pregnancy was predictive of GDM and incrementally improved risk identification, presenting potential for an early pregnancy, GDM risk screening strategy for streamlining of pregnancy care and opportunity for preventive intervention.

Lovastatin therapy in familial dysbetalipoproteinemia: effects on kinetics of apolipoprotein B.

Familial dysbetalipoproteinemia is characterized by hyperlipidemia, increases in beta-migrating, very low density lipoproteins (beta-VLDL), and homozygosity for apolipoprotein E2 (apo E2). In this study, 3 patients with familial dysbetalipoproteinemia were treated with lovastatin, and kinetics for apolipoprotein B (apo B) were determined in control and drug treatment periods. Multicompartmental analyses of apo B kinetics in VLDL and in low density lipoproteins (LDL) were carried out. Lovastatin therapy generally lowered plasma concentrations of apo B and cholesterol in VLDL and LDL. The reductions in concentrations were due mainly to a decrease in transport (production) rates for these fractions. Indeed, the fractional clearance rate (FCR) for LDL-apo B was reduced during lovastatin therapy. The decreased transport rate for VLDL-apo B and LDL-apo B could have been due to an inhibition of the synthesis of lipoproteins containing apo B. An alternate explanation is that lovastatin promoted direct removal of a rapidly-catabolized fraction of VLDL-apo B that is a precursor for longer-lived lipoproteins in the circulation; this mechanism could decrease input rates of identifiable lipoprotein species and retard their clearance because of "saturation" of LDL receptors by more rapidly removed lipoproteins. Finally, both mechanisms, i.e., decreased production and increased clearance of lipoproteins, may have contributed to the fall in VLDL-apo B and LDL-apo B concentrations during lovastatin therapy.

Clinical studies in a kindred with a kinetic LDL receptor mutation causing familial hypercholesterolemia.

We have studied a family carrying a variant of the class 2 mutation of familial hypercholesterolemia (FH) in which there is unusual longevity and in which obligate heterozygotes did not express constant or statistically significant hypercholesterolemia. The heterozygotes have the same kinetic defect in the processing of low density lipoprotein (LDL) receptors in their fibroblasts and the reduced fractional catabolic rate for apoLDL that is characteristic of other patients with heterozygous FH. However, their plasma lipid and lipoprotein levels are not as strikingly abnormal because they have normal or near normal rates of apoLDL synthesis.

Preliminary report: treatment of type 3 hyperlipoproteinemia with mevinolin.

Type 3 hyperlipoproteinemia (HLP) results from the accumulation in plasma of remnants of very low density lipoproteins (VLDL) due to a defect in apolipoprotein E. Current data suggest that VLDL remnants can be removed by the same receptors that remove low density lipoproteins (LDL). Mevinolin has been shown to enhance clearance of LDL by LDL receptors. In this study, mevinolin markedly lowered both VLDL remnants and LDL in a patient with type 3 HLP, presumably by increasing the activity of LDL receptors.

Increased catabolism of VLDL-apolipoprotein B and synthesis of bile acids in a case of hypobetalipoproteinemia.

A 29-year-old man is described who has reduced concentrations of low density lipoprotein (LDL)-cholesterol seemingly due to an unusual variant of hypobetalipoproteinemia. The patient developed retinitis pigmentosa at age 14. When studied at age 28, his total cholesterol was 104 mg/dL, triglycerides 58 mg/dL, LDL-cholesterol 44 mg/dL, and HDL-cholesterol 51 mg/dL. Lipid and lipoprotein levels of his parents and sister were normal. His excretion of bile acids (13.9 mg/kg/d) was markedly elevated at about three times normal, although absorption rates of cholesterol and bile acids appeared to be in the normal range. His high excretion of bile acids equates to a threefold increase in bile acid synthesis. Isotope kinetic studies of his lipoproteins produced unexpected findings. Total production of VLDL-apolipoprotein B (apo B) was estimated to be 20.8 mg/kg/d, which was in the normal range. Synthesis of VLDL-triglycerides was also normal at 12.0 mg/kg/h. However, 75% of VLDL-apo B was removed directly from the circulation, which was much higher than values for direct removal of VLDL-apo B in control subjects. His production rate of LDL-protein (5.2 mg/kg/d) consequently was below normal, although his fractional catabolic rate for LDL (0.40 pools/d) was not distinctly elevated. These data suggest that the patient's hypobetalipoproteinemia was due to increased direct removal of VLDL remnants and not to reduced synthesis of VLDL-apo B; this abnormality may have been the result of enhanced activity of LDL receptors, which in turn was secondary to increased synthesis of bile acids.