Role of group II secretory phospholipase A2 in atherosclerosis: 2. Potential involvement of biologically active oxidized phospholipids

Secretory nonpancreatic phospholipase A2 (group II sPLA2) is induced in inflammation and present in atherosclerotic lesions. In an accompanying publication we demonstrate that transgenic mice expressing group II sPLA2 developed severe atherosclerosis. The current study was undertaken to determine whether 1 mechanism by which group II sPLA2 might contribute to the progression of inflammation and atherosclerosis is by increasing the formation of biologically active oxidized phospholipids. In vivo measurements of bioactive lipids were performed, and in vitro studies tested the hypothesis that sPLA2 can increase the accumulation of bioactive phospholipids. We have shown previously that 3 oxidized phospholipids derived from the oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC) stimulated endothelial cells to bind monocytes, a process that is known to be an important step in atherogenesis. We now show that these 3 biologically active phospholipids are significantly increased in livers of sPLA2 transgenic mice fed a high-fat diet as compared with nontransgenic littermates. We present in vitro evidence for several mechanisms by which these phospholipids may be increased in sPLA2 transgenics. These studies demonstrated that polyunsaturated free fatty acids, which are liberated by sPLA2, increased the formation of bioactive phospholipids in LDL, resulting in increased ability to stimulate monocyte-endothelial interactions. Moreover, sPLA2-treated LDL was oxidized by cocultures of human aortic endothelial cells and smooth muscle cells more efficiently than untreated LDL. Analysis by electrospray ionization-mass spectrometry revealed that the bioactive phospholipids, compared with unoxidized PAPC, were less susceptible to hydrolysis by human recombinant group II sPLA2. In addition, HDL from the transgenic mice and human HDL treated with recombinant sPLA2 in vitro failed, in the coculture system, to protect against the formation of biologically active phospholipids in LDL. This lack of protection may in part relate to the decreased levels of paraoxonase seen in the HDL isolated from the transgenic animals. Taken together, these studies show that levels of biologically active oxidized phospholipids are increased in sPLA2 transgenic mice; they also suggest that this increase may be mediated by effects of sPLA2 on both LDL and HDL.

Low dose oral contraceptives and quality of life

This study investigated the effects of a low dose oral contraceptive (OC) (Mercilon) on women's satisfaction and quality of life based on a detailed questionnaire. A total of 614 first-time users of oral contraceptives were enrolled by 102 gynecologists for a treatment period of > or = 4 months. The Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) was filled in both before and during pill intake. The total quality of life score was significantly increased under OC intake. In contrast to older preparations, modern low dose OCs appear to act favorably on a number of psychological parameters, thus increasing satisfaction with various aspects of daily life and, consequently, improving quality of life.

CRM1-mediated recycling of snurportin 1 to the cytoplasm

Importin beta is a major mediator of import into the cell nucleus. Importin beta binds cargo molecules either directly or via two types of adapter molecules, importin alpha, for import of proteins with a classical nuclear localization signal (NLS), or snurportin 1, for import of m3G-capped U snRNPs. Both adapters have an NH2-terminal importin beta-binding domain for binding to, and import by, importin beta, and both need to be returned to the cytoplasm after having delivered their cargoes to the nucleus. We have shown previously that CAS mediates export of importin alpha. Here we show that snurportin 1 is exported by CRM1, the receptor for leucine-rich nuclear export signals (NESs). However, the interaction of CRM1 with snurportin 1 differs from that with previously characterized NESs. First, CRM1 binds snurportin 1 50-fold stronger than the Rev protein and 5,000-fold stronger than the minimum Rev activation domain. Second, snurportin 1 interacts with CRM1 not through a short peptide but rather via a large domain that allows regulation of affinity. Strikingly, snurportin 1 has a low affinity for CRM1 when bound to its m3G-capped import substrate, and a high affinity when substrate-free. This mechanism appears crucial for productive import cycles as it can ensure that CRM1 only exports snurportin 1 that has already released its import substrate in the nucleus.

Synthesis and properties of 2-(naphthosultamyl)methyl-carbapenems with potent anti-MRSA activity: discovery of L-786,392

A series of 1beta-methyl-2-(naphthosultamyl)methyl-carbapenems bearing dicationic groups on the naphthosultamyl moiety was prepared and evaluated for activity against resistant gram-positive bacteria. Based on a combination of excellent in vitro antibacterial activity, acceptable mouse acute toxicity, and a desirable fragmentation pattern on beta-lactam ring opening, the analog 2g (L-786,392) was selected for extended evaluation.

Efficacy, tolerability, and rare side effects of tibolone treatment in postmenopausal women

OBJECTIVE

The purpose of this study was to assess the tolerability and side effects of tibolone (Livial, Organon), a synthetic steroid analogue for the treatment of postmenopausal symptoms, in a large population of patients.

METHOD

1189 postmenopausal patients were included in this study. The patients' blood pressure, body weight, general complaints, and the severity of their climacteric complaints were documented at baseline and after 4 months of tibolone treatment.

RESULTS

Tibolone significantly relieved all of the classical menopausal complaints. The proportion of patients with bleeding problems dropped significantly from 15.9% to 6.8%. Other complaints, such as headache, vertigo, nervousness, breast tenderness, and hirsutism were also significantly less frequent than before treatment. Only few women reported other rare side effects, and only 14.4% of women discontinued treatment prematurely.

CONCLUSION

Tibolone provides an efficient and safe means of treating the postmenopausal syndrome in every-day practice.

Reduced immunotoxicity and preservation of antibacterial activity in a releasable side-chain carbapenem antibiotic

A carbapenem antibiotic, L-786,392, was designed so that the side chain that provides high-affinity binding to the penicillin-binding proteins responsible for bacterial resistance was also the structural basis for ameliorating immunopathology. Expulsion of the side chain upon opening of the beta-lactam ring retained antibacterial activity while safely expelling the immunodominant epitope. L-786,392 was well tolerated in animal safety studies and had significant in vitro and in vivo activities against methicillin- and vancomycin-resistant Staphylococci and vancomycin-resistant Enterococci.

An unusual chemical reactivity of Sm site adenosines strongly correlates with proper assembly of core U snRNP particles

The small nuclear ribonucleoprotein particles (snRNP) U1, U2, U4, and U5 contain a common set of eight Sm proteins that bind to the conserved single-stranded 5'-PuAU3-6GPu-3' (Sm binding site) region of their constituent U snRNA (small nuclear RNA), forming the Sm core RNP. Using native and in vitro reconstituted U1 snRNPs, accessibility of the RNA within the Sm core RNP to chemical structure probes was analyzed. Hydroxyl radical footprinting of in vitro reconstituted U1 snRNP demonstrated that riboses within a large continuous RNA region, including the Sm binding site, were protected. This protection was dependent on the binding of the Sm proteins. In contrast with the riboses, the phosphate groups within the Sm core site were accessible to modifying reagents. The invariant adenosine residue at the 5' end, as well as an adenosine two nucleotides downstream of the Sm binding site, showed an unexpected reactivity with dimethyl sulfate. This novel reactivity could be attributed to N7-methylation of the adenosine and was not observed in naked RNA, indicating that it is an intrinsic property of the RNA- protein interactions within the Sm core RNP. Further, this reactivity was observed concomitantly with formation of the Sm subcore intermediate during Sm core RNP assembly. As the Sm subcore can be viewed as the commitment complex in this assembly pathway, these results suggest that the peculiar reactivity of the Sm site adenosine bases may be diagnostic for proper assembly of the Sm core RNP. Consistent with this idea, a strong correlation was found between the unusual N7-A methylation sensitivity of the Sm core RNP and its ability to be imported into the nucleus of Xenopus laevis oocytes.

Sudden unexpected death in infancy: epidemiologically determined risk factors related to pathological classification

Infants that died suddenly and unexpectedly were studied as part of the European Concerted Action on sudden infant death syndrome (SIDS). Three paediatric pathologists, first independently of each other and later in a consensus meeting, classified 63 cases into 3 groups: SIDS (19 cases), borderline SIDS (30 cases) and non-SIDS (14 cases). The interobserver agreement among the pathologists before the consensus meeting was moderate (Kappa = 0.41) and jointly it was higher (Kappa = 0.83). The distribution of epidemiologically determined risk factors was studied over these three groups. Maternal smoking after birth, low socioeconomic status and thumb sucking were found more often in SIDS than in the other cases. Inexperienced prone sleeping was a determinant for SIDS, but not for non-SIDS. Previous hospital admission, low birthweight and/or short gestation were associated with borderline SIDS. Non-SIDS cases received more breastfeeding, the parents hardly smoked during pregnancy and after birth, a firm mattress had been used, and more often signs of illness had been reported by the parents, compared with the SIDS and borderline SIDS cases. Bedding factors and both primary and secondary prone sleeping were equally distributed over the three groups which supports the hypothesis that, in SIDS and borderline SIDS, as well as in non-SIDS cases, some similar external and preventable factors might influence the events leading to death. Research should therefore focus on all sudden unexpected deaths, after which subgroups such as SIDS cases can be separately analysed. The postmortem is an essential part of the whole work-up of each case and the results should be interpreted with all other available data to arrive at a sound evaluation of cases and thus form the basis for the prevention of all sudden unexpected infant death.

Pharmacokinetics of Implanon. An integrated analysis

The aims of this paper were to present data on the pharmacokinetics, clearance, bioavailability, and in vivo absorption of etonogestrel (ENG); to present the results of a longitudinal analysis of the plasma concentration-time curves of ENG; and to present the results of a cross-sectional analysis on the association of body weight with serum ENG concentrations. Implanon had an absorption rate of almost 60 micrograms/day after 3 months, which slowly decreased to 30 micrograms/day at the end of 2 years. The bioavailability over this period of time was constant and close to 100%. The clearance remained around 7.5 L/h. With a bioavailability and clearance that remained constant, it was concluded that accumulation of ENG does not occur. After Implanon insertion, serum concentrations increased within 8 h to concentrations associated with ovulation inhibition. Maximum mean serum concentrations (Cmax) amounted to 813 pg/mL and the time (tmax) to reach Cmax was 4 days. After reaching Cmax, ENG serum concentrations declined to about 196 pg/mL at the end of the first year, followed by a slow decline to 156 pg/mL at the end of the third year. After removal of Implanon, serum ENG concentrations declined to levels less than the detection limit of the assay (20 pg/mL) within 1 week. Lower body weight was associated with higher serum ENG concentrations.

Body composition characteristics after menopause

The effect of menstrual and reproductive history on body fat development after postmenopause was investigated in 278 healthy females aged between 44 and 67 years (x = 55.8 yrs). The absolute and relative amount of body fat was determined by means of dual energy x-ray absorptiometry. Significant associations between body fat after menopause and age at menarche, age at menopause, and average cycle length were observed. Furthermore the age at first as well as at last birth and the weight gain during pregnancies were related significantly with body fat after menopause. Overweight (BMI > 25.0) during postmenopause was significantly associated with an early menarche, a late menopause, an early first birth and a higher weight gain during pregnancies.

Case-control study of current validity of previously described risk factors for SIDS in The Netherlands

This study aimed to assess whether previously established risk factors for sudden infant death syndrome (SIDS) are still valid now that the incidence in the Netherlands has dropped to 0.26 per 1000 liveborn infants. A distinction was made between immutable and mutable risk factors. This case-control study (part of the European Concerted Action on SIDS) comprised 73 SIDS cases and 146 controls and lasted from March 1995 to September 1996. Adjustments were made for sleeping position and bedding factors by treating them as covariables. Apart from these factors, well known risk factors that remain of importance in the Netherlands are: male sex, young maternal age, twins, and low socioeconomic status. These factors are largely immutable. Other well known risk factors which might reflect attitudes to child care and could possibly be mutable are: smoking, alcohol consumption by the mother, bottle feeding, and change of babycare routine. Intervention strategies should focus on early signalling, thereby assisting parents in changing these unfavourable parenting attitudes. Information on optimal child care and extra support by public health nurses specifically aimed at families at risk could help to decrease further the incidence of SIDS in the Netherlands.

Pharmacokinetics of etonogestrel released from the contraceptive implant Implanon

Eight healthy women between 22 and 40 years of age participated in this prospective open study of 2 years' duration. Either on or between days 1 to 7 of a spontaneous menses, an intravenous bolus dose of 150 micrograms etonogestrel (3-ketodesogestrel) was given. During days 1-5 of a subsequent spontaneous cycle, the single-rod contraceptive implant (Implanon) was inserted in the upper arm of the volunteer. One year after placement of the implant, another intravenous bolus dose was given (implant in place), and a third bolus dose was given after 2 years, with the implant removed. Frequent serum sampling immediately after the intravenous dosings of etonogestrel was done to study the primary pharmacokinetic parameters, i.e., volume of distribution and clearance, allowing the calculation of the absorption rate and bioavailability of the implant, as a function of time. Results showed that etonogestrel released from Implanon has an absorption rate of approximately 60 micrograms/day after 3 months, which slowly decreases to 30 micrograms/day at the end of 2 years. The bioavailability over this period of time was constant and close to 100%. The clearance remained around 7.5 L/h. With a bioavailability and clearance that remained constant, it may be concluded that there is no accumulation of etonogestrel.

Risk and preventive factors for cot death in The Netherlands, a low-incidence country

In the Netherlands an 18 months case control study into cot death was undertaken as part of the European Concerted Action (ECAS) on sudden infant death syndrome to determine the relative risk of prone sleeping and other sleep practices. Physicians in the Netherlands were asked to report to the study centre all sudden and unexpected deaths of children between 1 week and 2 years of age. Non cot death cases were deleted from further analysis after a consensus was reached by three pathologists, not primarily involved in the post mortem diagnosis. A positive response of families was achieved in 91% of cases registered in the Central Bureau of Statistics. The study comprised 73 cot deaths and 146 controls, two for each case and matched for date of birth. All families were visited at home for completion of a questionnaire. The cot death rate has dropped considerably over the past 10 years after the recommendations on supine sleeping to a low of 0.26 per 1000 live born infants. In addition to the ECAS objective, we wanted to establish whether previously found risk factors are still valid in the present situation or that new factors might have emerged, some of them possibly protective.

CONCLUSION

Placing an infant prone or on side on last occasion, secondary prone position (not placed prone but turned to prone), inexperienced prone sleeping and use of a duvet, leading to head and body being covered, were shown to be risk factors. Preventive factors were using a cotton sleeping-sack and a dummy. Even in a low incidence country, such as the Netherlands, there are indications that further prevention is possible.

Snurportin1, an m3G-cap-specific nuclear import receptor with a novel domain structure

The nuclear import of the spliceosomal snRNPs U1, U2, U4 and U5, is dependent on the presence of a complex nuclear localization signal (NLS). The latter is composed of the 5'-2,2,7-terminal trimethylguanosine (m3G) cap structure of the U snRNA and the Sm core domain. Here, we describe the isolation and cDNA cloning of a 45 kDa protein, termed snurportin1, which interacts specifically with m3G-cap but not m7G-cap structures. Snurportin1 enhances the m3G-capdependent nuclear import of U snRNPs in both Xenopus laevis oocytes and digitonin-permeabilized HeLa cells, demonstrating that it functions as an snRNP-specific nuclear import receptor. Interestingly, solely the m3G-cap and not the Sm core NLS appears to be recognized by snurportin1, indicating that at least two distinct import receptors interact with the complex snRNP NLS. Snurportin1 represents a novel nuclear import receptor which contains an N-terminal importin beta binding (IBB) domain, essential for function, and a C-terminal m3G-cap-binding region with no structural similarity to the arm repeat domain of importin alpha.

[Hormonal etiology of secondary amenorrhea]

Over a 12-month period we evaluated 185 patients who consulted our outpatient department with symptoms of secondary amenorrhoea. Hormonal levels and body mass index were determined and an assessment made, on the basis of specific questioning. of the occurrence of possible mental alterations in the patients before they became amenorrhoic. Of our collective, 36 patients (19.5%) showed normal hormonal values, 50 patients (26%) were hypoestrogenemic, 46 women (25%) had elevated androgens, 15 patients (8%) had increased gonadotropins, 4 patients (2%) suffered from hyperprolactinemia, and 2 women (1%) had thyroid dysfunction. The remaining 32 amenorrhoic patients (17.2%) demonstrated different combinations of altered hormone values. The hypoestrogenemic patients showed a significant difference (p < 0.043) in body mass index in comparison with patients demonstrating normal hormone values. In contrast to reports in the literature hypoestrogenemia was the most frequent cause of secondary amenorrhoea in our study.

Aspects of progestin activity on the breast. European Progestin Club

On 9-11 May 1997, the second Meeting of the European Progestin Club was held in Turin, Italy. Aspects of progestin use on the breast were discussed, based on the currently available scientific data. The paper covers topics addressed at the meeting and summarizes the recommendations which could be agreed on by the participants.

The impact of nutritional status on body fat distribution patterns in pre- and postmenopausal females

This study examines the impact of nutritional status, classified by body mass index, on sex specific fat distribution patterns dependent on menopausal status in 467 pre-, peri- or postmenopausal females. Absolute and relative amounts of upper and lower body fat were estimated by means of dual energy X-ray absorptiometry. It was found that low weight, independent of menopausal status, leads to the typical gynoid pattern of fat distribution while excess weight and obesity result in the android pattern of distribution in pre- and postmenopausal women.

Hormonal response pattern in the combined DEX-CRH test is stable over time in subjects at high familial risk for affective disorders

One of the major neurobiological alterations in depressive disorders consists in a disturbed regulation of the hypothalamic-pituitary-adrenocortical (HPA) system. This is reflected by a pathological increase in the adrenocorticotropin (ACTH) and cortisol release after pretreatment with 1.5 mg dexamethasone (DEX) the previous night and a challenge with 100 micrograms corticotropin-releasing hormone (CRH) the next day. The changes evoked by this combined DEX-CRH test recede partially with an improvement of the psychopathological symptoms of depressed patients. It is still unclear, however, whether this long-lasting disturbance of the HPA system is due to acquired changes in the acute illness or whether it plays a causal role and could be considered as a trait or vulnerability marker for depression. In a previous study we have examined the HPA function of healthy probands with a high genetic load for affective disorders. We found that this group of high-risk probands (HRPs) showed abnormal DEX-CRH test results with a cortisol release that was between that of a control group and a group of patients with depression. In a follow-up study we now reexamined 14 of the 47 HRPs about 4 years after the index investigation and found surprisingly constant DEX-CRH test results, so that one of the requirements for a vulnerability marker is fulfilled.

Impact of the age at menarche on adult body composition in healthy pre- and postmenopausal women

The present study focuses on the impact of age at menarche on body composition development during adulthood. With 459 healthy middle-class women between 18 and 67 years (x = 41.5) the association between age at menarche and body composition was tested. Body composition, described by absolute and relative amount of fat mass, lean body mass, and bone mass, was estimated by means of dual energy x-ray absorptiometry. In order to exclude the influence of the menopausal transition on body composition, pre- and postmenopausal females were examined separately. The absolute amount of body fat was significantly lower within the group of women whose menarche occurred later. However, postmenopausal females exhibit less significant relations between the two trait systems than premenopausal women. This may be due to the impact of menopausal transition which affected the hormone levels and body composition development independently from the adolescent hormonal transition. While in both proband groups the quantitative amount of body fat was significantly related to menarcheal age, a significant relation between menarcheal age and adult body fat distribution could not be verified.

Anti-idiotype RNA selected with an anti-nuclear export signal antibody is actively transported in oocytes and inhibits Rev- and cap-dependent RNA export

The anti-idiotype approach is based on the assumption that an antibody specific for a receptor-binding domain of a ligand could be structurally related to the receptor. Therefore, a structural mimic of a receptor-binding domain, selected with an anti-ligand antibody, might be a functional substrate for the receptor. This hypothesis was addressed here by generating antibodies recognizing the Rev-nuclear export signal (NES). A functional NES is required for active export, presumably by interacting directly or indirectly with the nuclear pore complex. Anti-NES antibodies were used to isolate RNA mimics of the NES peptide from combinatorial RNA libraries. The RNA-mimics are exported actively, block Rev-dependent export of a reporter RNA, and inhibit cap-dependent U1 snRNA export in Xenopus oocytes, properties previously reported for NES-peptide conjugates.

Mex67p, a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores

An essential cellular factor for nuclear mRNA export called Mex67p which has homologous proteins in human and Caenorhabditis elegans was identified through its genetic interaction with nucleoporin Nup85p. In the thermosensitive mex67-5 mutant, poly(A)+ RNA accumulates in intranuclear foci shortly after shift to the restrictive temperature, but NLS-mediated nuclear protein import is not inhibited. In vivo, Mex67p tagged with green fluorescent protein (GFP) is found at the nuclear pores, but mutant mex67-5-GFP accumulates in the cytoplasm. Upon purification of poly(A)+ RNA derived from of UV-irradiated yeast cells, Mex67p, but not nucleoporins Nup85p and Nup57p, was crosslinked to mRNA. In a two-hybrid screen, a putative RNA-binding protein with RNP consensus motifs was found to interact with the Mex67p carboxy-terminal domain. Thus, Mex67p is likely to participate directly in the export of mRNA from the nucleus to the cytoplasm.