Isoreticular Chemistry of Group 13 Metal-Organic Framework Compounds Based on V-Shaped Linker Molecules: Exceptions to the Rule?

Following the concept of isoreticular chemistry, we carried out a systematic study on Ga-containing metal-organic frameworks (MOFs) using six V-shaped linker molecules of differing sizes, geometries, and additional functional groups. The linkers included three isophthalic acid derivatives (m-H₂BDC-R, R = CH₃, OCH₃, NHCOCH₃), thiophene-2,5-dicarboxylic acid (H₂TDC), and two 4,4'-sulfonyldibenzoic acid derivatives (H₂SDBA, DPSTA). The crystal structures of seven compounds were elucidated by a combination of model building, single-crystal X-ray diffraction (SCXRD), three-dimensional electron diffraction (3D ED), and Rietveld refinements against powder X-ray diffraction (PXRD) data. Four new Ga-MOFs that are isoreticular with their aluminum counterparts, i.e. Ga-CAU-10-R (Ga(OH)(m-BDC-R); R = OCH₃, NHCOCH₃), Ga-CAU-11 (Ga(OH)(SDBA)), and Ga-CAU-11-COOH (Ga(OH)(H₂DPSTC)), were obtained. For the first time large single crystals of a MOF crystallizing in the CAU-10 structure type could be isolated, i.e. Ga-CAU-10-OCH₃, which permitted a detailed structural characterization. In addition, the use of 5-methylisophthalic acid and thiophene-2,5-dicarboxylic acid resulted in two new Ga-MOFs denoted Ga-CAU-49 and Ga-CAU-51, respectively, which are not isostructural with any known Al-MOF. The crystal structure of Ga-CAU-49 ([Ga₄(m-HBDC-CH₃)₂(m-BDC-CH₃)₃(OH)₄(H₂O)]) contains an unprecedented rod-shaped inorganic building unit (IBU) of the formula _∞¹{Ga₁₆(OH)₁₈O₆₀}, composed of corner-sharing GaO₅ and GaO₆ polyhedra. In Ga-CAU-51 ([Ga(OH)(C₅H₂O₂S)]) chains of alternating cis and trans corner-sharing GaO₆ polyhedra form the IBU. A detailed characterization of the title compounds was carried out, including nitrogen gas and water vapor sorption measurements. Ga-CAU-11 was the only compound exhibiting porosity toward nitrogen with a type I isotherm, a specific surface area of a_S,BET = 210 m²/g, and a micropore volume of V_mic = 0.09 cm³/g. The new MOF Ga-CAU-51 exhibits exceptional water sorption properties with a reversible S-shaped isotherm and a high uptake around p/p₀ = 0.38 of m_ads = 370 mg/g.

Metal-Dependent and Selective Crystallization of CAU-10 and MIL-53 Frameworks through Linker Nitration

The reaction of the V-shaped linker molecule 5-hydroxyisophthalic acid (H2 L0 ), with Al or Ga nitrate under almost identical reaction conditions leads to the nitration of the linker and subsequent formation of metal-organic frameworks (MOFs) with CAU-10 or MIL-53 type structure of composition [Al(OH)(L)], denoted as Al-CAU-10-L0, 2, 4, 6 or [Ga(OH)(L)], denoted as Ga-MIL-53-L2 . The Al-MOF contains the original linker L0 as well as three different nitration products (L2 , L4 and L4/6 ), whereas the Ga-MOF mainly incorporates the linker L2 . The compositions were deduced by 1 H NMR spectroscopy and confirmed by Rietveld refinement. In situ and ex situ studies were carried out to follow the nitration and crystallization, as well as the composition of the MOFs. The crystal structures were refined against powder X-ray diffraction (PXRD) data. As anticipated, the use of the V-shaped linker results in the formation of the CAU-10 type structure in the Al-MOF. Unexpectedly, the Ga-MOF crystallizes in a MIL-53 type structure, which is usually observed with linear or slightly bent linker molecules. To study the structure directing effect of the in situ nitrated linker, pure 2-nitrobenzene-1,3-dicarboxylic acid (m-H2 BDC-NO2 ) was employed which exclusively led to the formation of [Ga(OH)(C8 H3 NO6 )] (Ga-MIL-53-m-BDC-NO2 ), which is isoreticular to Ga-MIL-53-L2 . Density Functional Theory (DFT) calculations confirmed the higher stability of Ga-MIL-53-L2 compared to Ga-CAU-10-L2 and grand canonical Monte Carlo simulations (GCMC) are in agreement with the observed water adsorption isotherms of Ga-MIL-53-L2 .

A Scandium MOF with an Unprecedented Inorganic Building Unit, Delimiting the Micropore Windows

A new scandium metal-organic framework (Sc-MOF) with the composition of [Sc(OH)(OBA)], denoted as Sc-CAU-21, was prepared under solvothermal reaction conditions using 4,4'-oxidibenzoic acid (H₂OBA) as the ligand. Single-crystal structure determination revealed the presence of the new inorganic building unit (IBU) {Sc₈(μ-OH)₈(O₂C)₁₆}. It is composed of cis-connected ScO₆ polyhedra forming an eight-membered ring through bridging μ-OH groups. The connection of the IBUs leads to a 3D framework, containing 1D pores with a diameter between 4.2 and 5.6 Å. Pore access is limited by the size of the IBU, and in contrast to the isoreticular aluminum compound Al-CAU-21 [Al(OH)(OBA)], which is nonporous toward nitrogen at 77 K, Sc-CAU-21 exhibits a specific surface area of 610 m² g^-1. The title compound is thermally stable in air up to 350 °C and can be employed as a host for photoluminescent ions. Sc-CAU-21 exhibits a ligand-based blue emission, and (co)substituting Sc³⁺ ions with Ln³⁺ ions (Eu³⁺, Tb³⁺, and Dy³⁺) allows the tuning of the emitting color of the phosphor from red to green. Single-phase white-light emission with CIE color coordinates close to the ideal for white-light emission was also achieved. The luminescence property was utilized in combination with powder X-ray diffraction to study in situ the crystallization process of Sc-CAU-21:Tb and Sc-CAU-21:Eu. Both studies indicate a two-step crystallization process, with a crystalline intermediate, prior to the formation of Sc-CAU-21:Ln.

Influence of the substitution pattern of four naphthalenedicarboxylic acids on the structures and properties of group 13 metal-organic frameworks and coordination polymers

Metal-organic frameworks containing Ga3+ ions and four differently substituted naphthalenedicarboxylates (ndc2-) have been synthesized and characterized. The Ga3+ ions are six-fold coordinated by oxygen atoms in all title compounds, but two different inorganic building units, i.e. trans corner-sharing and cis,trans edge-sharing octahedra are observed. Crystal structures were validated by Rietveld refinements against powder X-ray diffraction data. [Ga(OH)(1,4-ndc)]·2H2O crystallizes in a non-breathing MIL-53 type structure with two different pore sizes (5.5 × 5.5 Å and 9 × 9 Å). It is non-porous with respect to nitrogen but has a water adsorption capacity of about 155 mg g-1 and a thermal stability of up to 240 °C. The dense compound [Ga(OH)(1,8-ndc)] crystallizes in a new layered structure motif, which is related to the crystal structure of MIL-122 ([Al(OH)((O2C)4C6H2)]). The third and fourth compounds [Ga2(OH)4(2,3-ndc)]·H2O and [Ga(OH)(2,6-ndc)]·H2O are isoreticular to CAU-15 ([Al2(OH)4(2,3-bdc)]·H2O) and MIL-69 ([Al(OH)(2,6-ndc)]·H2O), respectively. The last two compounds are non-porous toward nitrogen but reversible dehydration was demonstrated. For comparison, the two new compounds [Al(OH)(1,8-ndc)] and [Al2(OH)4(2,3-ndc)]·H2O, which are isostructural to the newly described gallium compounds, were also synthesized and fully characterized. The Al-containing coordination polymers exhibit higher temperature stabilities compared to their isostructural Ga compounds.

Serum vitamin D levels and hypogonadism in men

There is inconsistent evidence on a possible association of vitamin D and androgen levels in men. We therefore aim to investigate the association of 25-hydroxyvitamin D (25(OH)D) with androgen levels in a cohort of middle-aged men. This cross-sectional study included 225 men with a median (interquartile range) age of 35 (30-41) years. We measured 25(OH)D, total testosterone (TT) and SHBG concentrations. Hypogonadism was defined as TT <10.4 nmol/L. We found no significant correlation of 25(OH)D and androgen levels. Furthermore, androgen levels were not significantly different across 25(OH)D quintiles. The overall prevalence of hypogonadism was 21.5% and lowest in men within 25(OH)D quintile 4 (82-102 nmol/L). We found a significantly increased risk of hypogonadism in men within the highest 25(OH)D quintile (>102 nmol/L) compared to men in quintile 4 (reference) in crude (OR 5.10, 1.51-17.24, p = 0.009) as well as in multivariate adjusted analysis (OR 9.21, 2.27-37.35, p = 0.002). We found a trend towards increased risk of hypogonadism in men within the lowest 25(OH)D quintile (≤43.9 nmol/L). In conclusion, our data suggest that men with very high 25(OH)D levels (>102 nmol/L) might be at an increased risk of hypogonadism. Furthermore, we observed a trend towards increased risk of hypogonadism in men with very low vitamin D levels indicating a U-shaped association of vitamin D levels and hypogonadism. With respect to risk of male hypogonadism, our results suggest optimal serum 25(OH)D concentrations of 82-102 nmol/L.

Highly sensitive determination of the polaron-induced optical absorption of organic charge-transport materials

We examine polaron-induced absorption in organic transport materials using a highly sensitive measurement technique. A hole only device is embedded into a low-loss TE2 waveguide structure, and the current induced change of the waveguide absorption is measured. The exemplary study of 2,2('),7,7(')-tetrakis(N,N-diphenylamine)-9,9(')-spiro-bifluorene (S-TAD) reveals a very low polaron absorption cross section of sigma(p) < or = 2.6 x 10(-18) cm(2) for 560 nm < or = lambda < or = 660 nm. The accuracy of this data is unsurpassed by other techniques used for the unambiguous study of polaronic species in organic thin films.

The use of hormone replacement therapy in patients after breast cancer

Four prospective randomized studies and at least 15 observational studies investigating hormone replacement therapy (HRT) after breast cancer are available. Only the Hormonal replacement therapy After Breast cancer: Is iT Safe (HABITS) study shows an increased risk of relapse. This is probably associated with the relatively high number of patients with HRT treatment after estrogen receptor-positive cancers as well as to the preferred use of estrogen/progestin combined preparations. As is generally known, the progestin component especially seems to be mainly responsible for the probability of increased diagnosis frequency of breast cancer. However, the patient samples in all studies investigating HRT after breast cancer are small. Therefore, HRT should only be used if alternatives, such as specific not contraindicated phyto-preparations or serotonin reuptake inhibitors, are not working. This is primarily due to forensic reasons. According to medical criteria, the data for the alternatives seem to be even more sparse, since many important questions remain unanswered, such as side effects and risks, or also regarding interactions with adjuvant hormone therapy.

[Malaria in the central highlands of Madagascar: control strategies]

The purpose of this article is to present data on malaria in the central highland plateaux of Madagascar and strategies to improve the national malaria control program. Use of rapid diagnosis strips, early home-based fever management with pre-packaged chloroquine treatment kits and proposed new therapeutic combination based on artemisinine are discussed for management of patients with high suspicion of malaria attack. Preventive measures including alternated targeted and full-house indoor spraying for vector control, use of insecticide-impregnated bednets, implementation of intermittent preventive treatment in risk groups, optimization of the epidemic early detection and warning system using the Lot Quality Assurance Sampling method for epidemiological investigation if the alert threshold is exceeded, and provision of rapid diagnosis strips are presented.

Induction of androgen receptor activity by norgestimate and norelgestromin in MDA-MB 231 breast cancer cells

The function and clinical significance of the androgen receptor (AR) in human breast cancer are still not clear. The synthetic progestins, norgestimate and norelgestromin, were designed to minimize the adverse effects such as acne, hirsuitism and metabolic changes observed with older oral contraceptives while maintaining contraceptive effectiveness and cycle control. AR-mediated effects of these synthetic progestins were studied in an in vitro transactivation assay, employing DNA co-transfection of an AR expression vector and luciferase reporter gene construct in the MDA-MB 231 human breast cancer cell line. Testosterone acetate and 5alpha-dihydrotestosterone induced the reporter gene transcription, whereas incubation of the transfected cells with the natural progestin 17alpha-hydroxyprogesterone did not markedly induce luciferase activity. The progestins norgestimate and norelgestromin exerted a very low androgenic activity. Our data suggest that norgestimate and its metabolite norelgestromin possess weak androgen-like properties. The use of these compounds for clinical application may be of great advantage in the treatment of breast cancer as well as hyperandrogenism in women.

Matrix metalloproteinase 2 and tissue inhibitor of metalloproteinase 2 expression is not regulated by norgestimate or norelgestromin

Steroid hormones regulate endometrial expression of matrix metalloproteinases (MMPs) and their inhibitors. Synthetic progestins are widely used in oral contraceptives and for hormone replacement therapy. To assess whether the synthetic progestins norgestimate and its derivative norelgestromin (17-deacetylnorgestimate) modulate the expression of MMPs, Ishikawa endometrial cancer cells were separately treated with 17 beta-estradiol, 17 alpha-hydroxyprogesterone, norgestimate and norelgestromin. Culture supernatants were assayed for MMPs 2, 3 and 9, and for tissue inhibitors of MMPs (TIMP-1 and TIMP-2) by enzyme-linked immunosorbent assays (ELISAs). No marked modulation of MMP-2 and TIMP-2 expression was observed upon incubation of the cells with the synthetic progestins. By ELISA, neither MMP-3 or MMP-9 nor TIMP-1 immunoreactivity was detected. Interestingly, TIMP-2 expression was down-regulated by 17 beta-estradiol and 17 alpha-hydroxyprogesterone.

Synthetic estrogen-mediated activation of ERK 2 intracellular signaling molecule

Ovarian steroids are important modulators of normal cell growth and differentiation as well as of carcinogenesis. External stimuli trigger cell surface receptors, resulting in activation of central signal transduction pathways, that are mediated by members of the mitogen-activated protein kinase (MAPK) family. These in turn, indirectly regulate cellular functions such as cell proliferation, cell cycle, and maintenance of malignant phenotype. In our in vitro study, we have investigated the effects of two synthetic estrogens on ERK 2 activation. Estrogen receptor positive cells were incubated with the synthetic estrogens, ethinylestradiol (10(-9) mol/l) and 17 beta-estradiol valerate (10(-9) mol/l), epidermal growth factor (EGF) (10 ng/ml) and the natural estrogen 17 beta-estradiol (10(-9) mol/l), for 5 min. The same experiments were repeated prior to preincubation with the antiestrogen ICI 182780. ERK 2 or the active form alone were detected by immunoblotting. A cell proliferation assay was used to study the response of cells to various treatments. Time kinetics were performed to study duration of kinase activated state. Cell incubation with EGF as well as with either natural or synthetic estrogen stimulated proliferation. ICI 182780 inhibited this effect, but only in the case of estrogen. Synthetic estrogens activated MAP kinase in a time-dependent fashion, similar to 17 beta-estradiol. The estrogen receptor antagonist ICI 182780 blocked this effect. EGF induced a more pronounced and prolonged activation, even in the presence of the antiestrogen. Ethinylestradiol as used in oral contraceptives, and 17 beta-estradiol and 17 beta-estradiol valerate as used in hormone replacement therapy, are able to activate MAP kinase. This activation was blocked by an antiestrogen.

Impact of obesity and leptin levels on the secretion of estradiol, inhibin A and inhibin B during ovarian stimulation with gonadotropins

We examined the impact of high leptin levels on the secretion of estradiol, inhibin A and inhibin B in obese and lean women during ovarian stimulation. Patients undergoing long-term pituitary suppression, ovarian stimulation and in vitro fertilization for non-endocrine reasons were included in this case-control study. Obese women (body mass index (BMI) > 28 kg/m(2); n = 17) were individually matched with lean women (BMI 20-25 kg/m(2); n = 17) for age and baseline follicle stimulating hormone and luteinizing hormone concentrations. Blood samples were collected in a previous menstrual cycle and 1-3 days apart throughout ovarian stimulation. Serum levels of estradiol, leptin, inhibin A and inhibin B were measured. Obese and lean women had similar serum concentrations of estradiol, inhibin A and inhibin B in the follicular and luteal phases of the spontaneous menstrual cycle, and throughout ovarian stimulation. Serum levels of leptin were higher in obese than in lean women, and increased during stimulation in both groups. In the obese group, area-under-the-curve (AUC) leptin levels correlated with AUC inhibin A levels. In the lean group, there was no correlation between AUC leptin levels and AUC levels of ovarian hormones. The results suggest that high leptin concentrations in vivo are not associated with impaired secretion of estradiol and dimeric inhibins during ovarian stimulation.

Isolation and identification of antibacterial compounds from Vernonia colorata leaves

Vernonia colorata (Compositae) is used throughout Africa for a variety of ailments. This prompted the screening of this plant for biological activity. Previous experiments carried out in our laboratory revealed that the leaves possessed high antibacterial activity. Through conventional chromatographic techniques and bioassay-guided fractionation, the following sesquiterpene lactones were isolated and identified by spectroscopic data; vernolide (1), 11beta, 13-dihydrovernolide (2) and vernodalin (3). Only 2 is a novel compound, although its antibacterial activity is low compared to compounds 1 and 3 which had minimum inhibitory concentrations of 0.1-0.5 mg/ml against Gram-positive bacteria.

South-East Asian ovalocytosis among the population of the Highlands of Madagascar: a vestigé of the island's settlement

In the Madagascar Highlands, 0.76% of children from 168 random primary schools, and 19 of 150 families from 3 villages, had oval-shaped erythrocytes. Most harboured the deletion in the band 3 gene characteristic of South-East Asian ovalocytosis. This genetic trait supports the Indonesian origin of the Madagascar settlement.

Preclinical profiles of progestins used in formulations of oral contraceptives and hormone replacement therapy

Progestins used in oral contraceptive formulations available in the United States include norgestimate, desogestrel, norethindrone, norethindrone acetate, and levonorgestrel. Progestins used in the United States in continuous and intermittent formulations of hormone replacement therapy are norgestimate, medroxyprogesterone acetate, and norethindrone acetate. The chemical structure of a progestin determines its relative binding affinity for the progesterone and androgen receptors, as well as the sex hormone binding globulin in human serum, and determines its clinical profile. Overall, the properties of levonorgestrel or norethindrone acetate in this regard differ from norgestimate and are more conducive to androgenic stimulation. Estrogen replacement offers cardioprotective effects in postmenopausal women. Progestins are added to hormone replacement therapy to counteract the well-known increased risk of endometrial hyperplasia associated with the use of unopposed estrogen. Animal models show that for some parameters, including improvement of lipid profiles, progestins can diminish the cardioprotective effect of estrogen. Initial animal studies of norgestimate combined with estrogen do not show an attenuation of estrogenic effects.

Synthetic estrogens-mediated activation of JNK intracellular signaling molecule

Signal transduction pathways regulate the transmission of specific signals to the cells from the surface to the nucleus. Activation of protein kinases such as JNKs (c-jun amino-terminal kinase), a subgroup of the mitogen activated protein kinase (MAPK) family, results in regulation of important cellular functions like cell growth and differentiation. The involvement of estrogens in stimulation of growth of already transformed breast cancer cells in vivo and in vitro accompanied with activation of JNKs prompted us to investigate the role of synthetic estrogens in the regulation of JNK expression. T 47D breast cancer cells were incubated with the synthetic estrogens, ethinylestradiol (10(-9)M) and 17 beta-estradiol valerate (10(-9)M), epidermal growth factor (EGF) (10 ng/ml) and the natural estrogen, 17 beta-estradiol (10(-9)M), for 5 minutes. The same experiments were repeated after pretreatment of the cells with ICI 182780 for 24 hours. EGF as well as natural and synthetic estrogens stimulated proliferation. This effect was reversed by the estrogen receptor blocker ICI 182780, but only in the case of both natural and synthetic estrogen. Like 17 beta-estradiol, synthetic estrogens induced a rapid and transient activation of JNK kinase. ICI 182780 blocked this effect, but not that mediated by EGF. Ethinylestradiol used in oral contraceptives, and 17 beta-estradiol and 17 beta-estradiol valerate for hormone replacement therapy, are able to activate JNK. The estrogen receptor is necessary for JNK activation upon estrogen stimulation.

An investigation on the biological activity of Combretum species

Leaf extracts of 20 Combretum species, many of which are used in southern African traditional medicine, were screened for anti-inflammatory, anthelmintic, anti-bilharzia (antischistosomal) and DNA-damaging activity. Significant activity in more than one bioassay was exhibited by Combretum apiculatum, Combretum hereroense, Combretum molle and Combretum mossambicense. Ethyl acetate extracts were generally most active, followed by acetone and then water extracts.

Malaria in the highlands of Madagascar after five years of indoor house spraying of DDT

The central region of Madagascar is a vast area of highlands (altitude 700-2000 m). Malaria transmission has re-established itself here since the last epidemic of 1985-90 and has caused the deaths of 40,000 persons according to the Minister of Health. To combat the main malaria vector in the region, Anopheles funestus, annual programmes of indoor house spraying of DDT were carried out between December 1993 and January 1998 in most rural areas at altitude 1000-1500 m. A parasitological and serological study was then conducted in the highland schools to evaluate the impact of the programme and set up a database on the region. Using a cluster-sampling method 2 independent selections were conducted (one of 130 sites, the other of 40 sites). During the study, 13,462 schoolchildren were examined, 71% living in sprayed villages. Parasite prevalence among schoolchildren declined as altitude increases, from 11% at 700-900 m to 0.4% at > 1500 m. Below 1500 m, the impact of the spraying on the prevalence of the parasite was very clear (an average decrease of from 20% to 2.7% below 1000 m and of from 4.5% without spraying to 0.8% at 1000-1500 m). Geographical analysis of the data showed that the marginal regions remained the most affected by malaria (especially outside spraying zones), and persistence of 'pockets of transmission' at 1000-1500 m, essentially in areas where spraying has never been used. In 9 schools, anti-Plasmodium antibodies were sought by indirect immunofluorescence on thick smears of parasitized red blood cells. The seroprevalence ranged from 22% to 63%, which suggests that the parasite is still circulating in the region. Even though our data show that vector control continues to be very successful in the Madagascan highlands, rapid reinfection could occur and must be monitored following spraying. To this end, the Minister for Health, with the support of the Italian Co-operation, has placed the region under epidemiological surveillance since 1997. An alert system for the timely detection of the sources of epidemics and the targeting of the antivectoral campaign is also in operation. Our study suggests that this strategy should be reinforced by the spraying of DDT in the marginal zones in order to consolidate the results obtained at higher altitudes.

Isolation of an antibacterial sesquiterpenoid from Warburgia salutaris

The bark of Warburgia salutaris is used in traditional medicine as an expectorant and smoked for coughs and colds, including a topical application for sores and inflammation. A previous screening of South African medicinal plants showed that this plant had promising antibacterial activity. Subsequently, this endangered tree species was selected for bioassay-guided fractionation in order to identify the active principles. Fractionation of the ethyl acetate extract of the stem bark by chromatographic techniques yielded a sesquiterpenoid which exhibited antimicrobial activity against Gram-positive bacteria. The compound, muzigadial, has previously been reported in two other Warburgia species, this being the first time it has been reported from W. salutaris. Muzigadial had minimum inhibitory concentration values ranging from 12.5 to 100 microg ml(-1).

Influence of 5-lipoxygenase on in vitro growth of human mammary carcinoma cell line MCF-7

The aim of this study was to investigate the direct effect of 5-lipoxygenase (5-LO) on the growth of human mammary cancer cells MCF-7 in vitro. Cell growth was measured according to the level of 3H-thymidine incorporation. 5-LO was shown to inhibit 3H-thymidine incorporation. The inhibitory effect was 19, 42 and 78% when administered at concentrations of 0.1, 0.2 or 0.5 U/ml, respectively. Its effect was time- and dose-dependent and was statistically significant at concentrations of 0.2 and 0.5 U/ml. We have also shown that the specific 5-LO inhibitor MK-886 (1 microM) lifts the inhibitory effect of 5-LO (0.2 U/ml). Moreover, when treated with an activator of 5-lipoxygenase calcium ionophore A23187 (10 microM) MCF-7 cells synthesize LTB4. The results of this study are evidence of the role of 5-lipoxygenase in the regulation of human mammary cancer cells growth in vitro.

Inhibition of skin 5 alpha-reductase by oral contraceptive progestins in vitro

Androgenic disorders of female skin such as hirsutism, acne and alopecia are etiologically caused by androgen excess. Skin 5 alpha-reductase activity is a major factor influencing the manifestation of endogenous androgen excess in women. Oral contraceptives have proven useful for the treatment of androgen disorders of the skin. The mechanisms of action by which oral contraceptives correct skin androgen levels may include inhibition of 5 alpha-reductase and androgen receptor activity. We investigated the inhibitory effect of oral contraceptive progestins and ethinyl estradiol on skin 5 alpha-reductase and their influence on androgen receptor activity and affinity, using three different in vitro assay systems. It was shown that norgestimate blocked 5 alpha-reductase activity with an IC50 value of 10 microM, followed by levonorgestrel (IC50 52 microM), dienogest (IC50 55 microM), cyproterone acetate (IC50 87 microM) and gestodene (IC50 98 microM). To determine the full androgenic potential of the progestins, androgen receptor binding affinities and activation potentials were determined. The progestins norgestimate and dienogest in particular combined 5 alpha-reductase inhibition with minimal androgenic potential. These data demonstrate that the progestins norgestimate and dienogest might help in the treatment of clinical hyperandrogeny in women.

Plant part substitution--a way to conserve endangered medicinal plants?

Population growth, urbanization and the unrestricted collection of medicinal plants from the wild is resulting in an over-exploitation of natural resources in southern Africa. Therefore, the management of traditional medicinal plant resources has become a matter of urgency. In southern Africa the most frequently used medicinal plants are slow-growing forest trees, bulbous and tuberous plants, with bark and underground parts being the parts mainly utilized. A strategy which would satisfy the requirements of sustainable harvesting, yet simultaneously provide for primary health care needs, would be the substitution of bark or underground parts with leaves of the same plant. This paper outlines the concept of plant substitution, using preliminary results of our recent investigations into four of the most important and most threatened South African medicinal plants - Eucomis autumnalis (bulb), Siphonochilus aethiopicus (rhizome), Ocotea bullata (bark), and Warburgia salutaris (bark) - as a demonstration of the kind of research necessary. Extracts of various plant parts were compared chemically using TLC-analysis, and pharmacologically in terms of antibacterial activity and cyclooxygenase-1 inhibition in vitro. The importance of the concept of plant part substitution as a strategy for the conservation of medicinal plants in southern Africa is discussed in terms of the results obtained.

[Non-contraceptive benefits of the pill--an often neglected fact]

While rare cardiovascular risks of oral contraceptives (OCs) caused a lot of concern among OC-using women in the recent past, little attention has been paid in the public to the non-contraceptive benefits of OCs. Short, medium and long term non-contraceptive benefits have to be considered. The early Anglo-American cohort and case-control studies demonstrated a reduction of menstrual complaints, iron-deficiency anaemia, ectopic pregnancies, and a partly drastic reduction of some benign and malignant tumours such as endometrial and ovarian cancer. A risk reduction of rheumatoid arthritis is discussed controversially. The present paper gives an overview of the state of knowledge. For newer OCs with different composition, comparable studies are lacking. Therefore, a cohort study was initiated in Germany in April 1998 to investigate these associations as well for newer OCs, which is presented. The described non-contraceptive benefits should be considered in the benefit-risk assessment when prescribing OCs.

[German Cohort Study of Women's Health--benefits of oral contraceptives. Study protocol]

This publication is about the study protocol of the German Cohort Study on Women's Health. The main objective is to investigate medical benefits of a long-term oral contraceptive use. The design is an analytical cohort study based on inquiries. Additional cases will be recruited to analyse rare events in separate case-control studies. Voluntary participants who signed to participate in a long-term study are included. An annual drop-out rate of 15% is expected. Study variables encompass personal characteristics, lifetime history of diseases, but also disturbances of the state of health, and quality of life. It is anticipated to achieve 400,000 women-years of observation by 2001 (historic and concurrent follow-up). The study started April 1, 1998 and the current financial phase finishes December 31, 2001. 6000 participants were recruited until December 1998 equivalent to about 190,000 observation-years. Until the end of 1999, an additional 70,000 women-years should be included. There have been many suggestions from participants' to include additional issues of women's health into the study.

Induction of estrogen receptor-alpha and -beta activities by synthetic progestins

The cellular action of steroid hormones is mediated by specific receptors. Recently, two different estrogen receptors (ER), alpha and beta, have been cloned with a specific tissue distribution. Active estrogen as well as active progestin are compounds of oral hormonal contraceptives and hormone replacement therapy. To examine the regulation of ER-alpha and -beta activities after treatment with synthetic progestins and synthetic and natural estrogens, COS 7 cells were transfected with the vector expressing ER-alpha and -beta in combination with a luciferase reporter vector. ER-alpha activity was upregulated in the presence of synthetic progestins in a dose-dependent manner. Norethisterone, norethynodrel and desogestrel proved to be the most potent stimulatory agents of ER-alpha expression. On the other hand, not all progestins exhibited a stimulatory action on ER-beta activity. Only norgestrel, levonorgestrel, norethynodrel and norethisterone induced ER-beta-activating functions in a dose-dependent manner. Luciferase activity due to estrogen stimulation served as a positive control. Our results indicate that progestins have different effects on the activities of ER-alpha and -beta.

Aneuploidy in human granulosa lutein cells obtained from gonadotrophin-stimulated follicles and its relation to intrafollicular hormone concentrations

Proliferation of granulosa cells is inversely related to differentiation and hormone production. The purpose of this study was to evaluate the intrafollicular and serum steroid concentrations and to compare these results to granulosa cell proliferation as measured by DNA flow cytometry. Human granulosa lutein cells in follicular fluid of in-vitro fertilization (IVF) patients were investigated with regard to ploidy, percentage of S-phase cells and proliferation index (PI: percentage of cells in the S- and G2/M-phase). The study was originally designed to indicate an additional marker for the outcome of IVF treatment by DNA flow cytometric measurements of granulosa lutein cells. Follicular fluids of 160 follicles (45 patients) were evaluated; 45.6% (n = 73) of the follicles showed aneuploid granulosa lutein cells and 5.6% (n = 9) of the follicles contained multiploid granulosa cells, defined as at least two aneuploid populations of cells with different DNA indices. A total of 48.8% (n = 78) of the follicles had only diploid cells. Thus >50 % of the investigated follicles showed aneuploidy. In all, 73% (33 of 45) of patients had at least one follicle containing aneuploid granulosa lutein cells. The PI of the aneuploid cell populations significantly exceeded that of the diploid cell populations (median: aneuploid: 15.5; diploid: 7.4; P < 0.0001). The intrafollicular concentrations of testosterone, progesterone and dehydroepiandrosterone sulphate (DHEA-S) were significantly lower in follicles with aneuploid granulosa cell populations. Luteinizing hormone concentration was significantly higher in follicles with aneuploid granulosa cells. Intrafollicular concentrations of oestradiol, follicle stimulating hormone and the serum concentrations of all steroid hormones did not show any significant correlation to ploidy. Although aneuploidy has been reported for oocytes (in approximately 17% of the oocytes), no study, to our knowledge, has observed such a high incidence of aneuploidy in granulosa lutein cells after gonadotrophin stimulation. Except for aneuploidy found in tissues with some characteristics of neoplastic growth (colon adenoma, borderline tumours, endometriosis with atypic cells, etc.), it is unique for non-malignant human cells. The correlation with intrafollicular steroid concentrations points to a possible pathophysiological or physiological relevance of these findings. However, it was impossible to correlate the outcome of IVF with DNA flow cytometry results.

[Malaria in Antananarivo: evaluation of a post-epidemic situation]

Antananarivo has a population of close to one million inhabitants and is located in the highlands of Madagascar. The capital was, until some years ago, thought to be a malaria transmission-free zone. However, between 1985 and 1990, several malaria cases occurred in the suburbs of Antananarivo, along the Ikopa river (the Betsimitatatra Plain), suggesting that local transmission was occurring. Numerous malaria cases have since been reported by health workers each year, but there is insufficient epidemiological information about the cause and origin of the transmission, because cases are rarely confirmed by parasitological examination. The National Malaria Control Management in Madagascar has, after four years of intensive DDT spraying campaigns in the highlands, stopped this specific method of control. Epidemiological follow-up studies will be carried out to evaluate the effects on malaria transmission of this cessation of control measures. The transmission of malaria in Antananarivo was studied from 1995 to 1996. Patients from nine health centers in various suburbs of Antananarivo were included in the study, with the presence of fever used as the sole inclusion criterion. Children randomly selected from schools in the same area were included in a second study group. A blood sample was obtained from each participant to determine the parasite index and the prevalence of antibodies against P. falciparum. The splenic index was also determined. A second assessment was performed for the school children six months later, using the same markers of malaria infection. Nine hundred and thirty two patients from the health center group were referred for participation in the study. This represented 10% of all patients and 74% of the patients with fever. The school group included 1,545 children. The splenic index was similarly low (0.5%) in the health center and school groups, as was the overall parasite index (2.6% for the health center group and 0.8% in the school group). The prevalence of antibodies against P. falciparum was also low, but with a seasonal variation: 2.5% in June 1995 and 11.6% in January 1996. Almost all the cases confirmed by parasitological examination were due to the patient having stayed in an area with hyperendemic malaria or having been in contact with an individual who had been to an area with a high level of transmission. Our findings confirm that Antananarivo is now in a post-epidemic situation. Malaria cases are mostly associated with a history of travel in areas with high levels of malaria transmission, particularly the coastal regions of Madagascar. Nevertheless, a low level of transmission may persist and lead to further outbreaks of malaria in the future, due to the presence in the area of Anopheles arabiensis.

Influence of leukotrienes on in vitro growth of human mammary carcinoma cell line MCF-7

OBJECTIVES

The aim of this work was to study the action of leukotrienes on the growth of human mammary cancer cells MCF-7.

STUDY DESIGN

The growth of the cells was measured by incorporation of 3H-thymidine. The action of leukotriene (LT)B4, LTD4, LTC4, LTE4 or arachidonate (AA) was tested in human mammary cancer cells MCF-7 in vitro.

RESULTS

LTB4 or LTD4 but not LTC4 or LTE4 reduced significant incorporation of 3H-thymidine in MCF-7 cells up to 52% or 56% respectively, when administered in concentrations 0.1-1000 pM. Agents in concentrations of 0.01 pM or 10000 pM did not effect 3H-thymidine incorporation. We have shown, that MCF-7 cells synthesise LTB4 when treated with calcium ionophor A23187 (10 microM). Leukotriene-antagonist LY171883 (10 microM) lifts inhibitory effects of LTB4 or LTD4. Arachidonic acid (10 microM) inhibits 3H-thymidine incorporation up to 72%. 5-lipoxygenase inhibitor MK-886 (100 nM) lifts the inhibitory effect of arachidonate.

CONCLUSIONS

LTB4 or LTD4 inhibits MCF-7 breast cancer cell growth. LT-receptors mediate the growth-inhibitory effect of LTB4 or LTD4.

Effect of central and ovarian endocrine disturbances on the female genital tract--clinical signs and symptoms

Disorders of the female genital tract caused by endocrine disturbances commonly lead to two presenting complaints: dysfunctional uterine bleeding and infertility. In oestrogen deficiency, sequelae of vaginal atrophy may also be present. The common pathogenic "turntable" of these clinical signs is an impaired ovarian function, for which primary (i.e. intraovarian) and secondary (i.e. resulting from dysfunctions of other endocrine systems) causes are known. Primary ovarian failure can be the result of gonadal dysgenesis or premature menopause. Secondary ovarian dysfunction may be caused by hypothalamic-pituitary dysregulation, hyperprolactinaemia, thyroid disorders, and hyperandrogenaemia, which often also has an intraovarian component. For clinical considerations, several severities of ovarian dysfunction can be distinguished, ranging from corpus luteum insufficiency which is only relevant for the selection of infertility treatment to the complete absence of ovarian steroidogenesis leading to severe long term sequelae of the skeletal, cardiovascular and probably central nervous systems. Diagnosis and differential diagnosis are made by clinical examination, vaginal ultrasound, hormone assays, curettage and laparoscopy. Rarely, additional techniques like magnetic resonance imaging of the pituitary or the adrenals, or sequential catheterization of the inferior vena cava are needed.

Spacing-out of progestin--efficacy, tolerability and compliance of two regimens for hormonal replacement in the late postmenopause

Estrogen replacement therapy with sequential progestin at greater than monthly intervals has been frequently used in practice to reduce progestational side-effects and bleeding episodes, but clinical trials are still lacking. Two new regimens were tested. The main objective was to evaluate efficacy, predominantly in urogenital complaints, tolerability, and patient acceptance. Transdermal estradiol (0.05 mg/day) and norethisterone acetate orally (2.5 mg/day) were administered for 12 days every 2 or 3 months (group A, n = 83, group B, n = 89) to patients whose menopause had begun at least 4 years earlier. Study duration was three long cycles in each group within 7-10 months. Efficacy was good [group A/B = 94/92%], as was systemic tolerability [95/97%]; major skin reactions occurred in 7 and 4%, respectively. Patients' acceptance for continuation of spaced-out treatment was 88 and 87%, respectively. Progestin-associated withdrawal bleedings occurred in 66 (61%) of patients; mean duration 4.3 +/- 1.9/4.8 +/- 1.6 days, with no significant changes during therapy; intensity decreased during therapy. Breakthrough bleeding which required sonographic or histological work-up occurred in 8 and 13%, respectively. Despite the low dosage, transdermal estradiol proved to be efficacious in urogenital complaints. The high acceptance and the reduction of the overall progestin dose to avoid side-effects are of particular prognostic importance with regard to the prevention of cardiovascular diseases. Transdermal estradiol combined with 2- or 3-monthly progestin may be a valid regimen in the late post-menopause, but further studies using spacing-out regimens are urgently needed.

A study of the influence of a gestodene-containing triphasic oral contraceptive on endometrial morphology

The objective of the study was to investigate histological changes in the endometrium in 20 volunteers treated with a low-dose, gestodene-containing triphasic oral contraceptive. Endometrial biopsy specimens were taken before, during a 6-month period of oral contraceptive use and in a post-treatment period. These specimens were evaluated using light microscopy, scanning and transmission electron microscopy. In addition, ultrasound examinations of the uterus, endometrial thickness and ovaries were performed. The low-dose, gestodene-containing triphasic oral contraceptive had no adverse effects on the endometrium (e.g. no proliferation, no polyps, no inflammatory processes), was well tolerated and showed a low side-effect profile. The inhibition of endometrial transformation was demonstrated both by endometrial morphology as well as by endometrial thickness, as measured by transvaginal ultrasound examination.

Inhibitory effect of leukotrienes on luteinizing hormone release

The aim of this work was to study the effect of high concentrations of leukotrienes on luteinizing hormone (LH) secretion in rat anterior pituitary cells. We also investigated the effect of leukotrienes in parallel with gonadotropin-releasing hormone (GnRH) action. Experiments were on cells gained from trypsinized pituitaries of female rats. Tests were performed by superfusion of the cells attached to cytodex-1 carrier beads. The LH content in samples of perfusate was estimated by radioimmunoassay. This work reports 48% inhibition of basic LH release by action of leukotriene C4 in superfused cells when applied continuously at a concentration of 100 nmol/l. Moreover, we have shown that leukotrienes suppressed GnRH-induced LH secretion in rat pituitary cells when applied in parallel to GnRH (1 nmol/l) as a 4-min pulse at a concentration of 0.1 nmol/l. GnRH-induced LH release was reduced to 66% of its value by leukotriene (LT) B4 (0.1 nmol/l) action; also to 54% by LTC4, 66% by LTD4 and 74% by LTE4 action. In contrast, arachidonic acid (50 pmol/l) and its other 5-lipoxygenase metabolites: 5-hydroperoxyeicosatetraenoic acid (5-HPETE) (50 pmol/l), or 5-hydroxyeicosatetraenoic acid (5-HETE) (50 pmol/l), had no inhibitory effect on GnRH-induced LH release. Arachidonic acid and 5-HETE potentiated GnRH-induced LH release up to 249% and 429%, respectively, when applied in parallel with GnRH (1 nmol/l) as a 4-min pulse at a concentration of 10 pmol/l. In our earlier work we have shown that several leukotrienes are potent stimulants of LH release. The present report documents the finding that the 5-lipoxygenase pathway is also involved in the inhibitory regulation of hormone release in anterior pituitary cells.