Availability of diagnostic services and essential medicines for non-communicable respiratory diseases in African countries.

BACKGROUND: The global burden of disease due to asthma and chronic obstructive pulmonary disease (COPD) is substantial and particularly great in low- and middle-income countries, including many African countries. Management is affected by availability of diagnostic tests and essential medicines. The study aimed to explore the availability of spirometry services and essential medicines for asthma and COPD in African countries.METHOD: Questionnaires were delivered to healthcare workers at the annual meeting of the Pan African Thoracic Society Methods in Epidemiology and Clinical Research (PATS MECOR) and International Multidisciplinary Programme to Address Lung Health and TB in Africa (IMPALA). Data were analysed using simple descriptive statistics.RESULTS: A total of 37 questionnaires representing 13 African countries were returned. Spirometry availability was 73.0%. The most common reasons for non-availability were lack of knowledge of the utility of the test. Within the study sample, 33.3% faced sporadic availability due to maintenance issues. Essential medicines availability ranged from 37.8% for inhaled corticosteroid-long-acting beta-agonist inhalers to 100% for prednisolone 5 mg tablets, mainly due to supply chain problems.CONCLUSION: There is varied availability of spirometry and WHO essential medicines for COPD and asthma in African countries. Strategies are needed to improve access to basic effective care for people with non-communicable lung disease in Africa.

Epizooic metazoan meiobenthos associated with tubeworm and mussel aggregations from cold seeps of the northern Gulf of Mexico.

The abundance and higher taxonomic composition of epizooic metazoan meiobenthic communities associated with mussel and tubeworm aggregations of hydrocarbon seeps at Green Canyon, Atwater Valley, and Alaminos Canyon in depths between 1400 and 2800 m were studied and compared to the infaunal community of non-seep sediments nearby. Epizooic meiofaunal abundances of associated meiobenthos living in tubeworm bushes and mussel beds at seeps were extremely low (usually <100 ind. 10 cm(-2)), similar to epizooic meiofauna at deep-sea hydrothermal vents, and the communities were composed primarily of nematodes, copepods, ostracods, and halacarids. In contrast, epizooic meiobenthic abundance is lower than previous studies have reported for infauna from seep sediments. Interestingly, non-seep sediments contained higher abundances and higher taxonomic diversity than epizooic seep communities, although in situ primary production is restricted to seeps.

Retinoid signaling by all-trans retinoic acid and all-trans retinoyl-beta-D-glucuronide is attenuated by simultaneous exposure of human keratinocytes to retinol.

Retinol and retinyl esters are converted with time to slowly increasing amounts of all-trans retinoic acid (RA) in cultured human keratinocytes. Exogenous RA has been shown to limit retinol oxidation and to increase retinol esterification. Because significant amounts of retinol are present in biologic systems, we examined whether RA and all-trans-retinoyl-beta-D-glucuronide (RAG) interact with retinol in exhibiting their activities on HaCaT keratinocytes maintained in a retinoid-free culture system. RA was more potent than RAG and retinol in inducing ultrastructural changes attributed to retinoids, inhibiting cell proliferation as well as enhancing keratin 19 expression. In addition, retinoids were able to induce cellular retinoic acid-binding protein II mRNA levels in the cultures, whereas early RA and late RAG activity was detected. The described biologic effects of RA and RAG were diminished by simultaneous cell exposure to retinol. HaCaT cells quickly metabolized retinol to retinyl esters and consequently to low amounts of RA. RA treatment led to an early high peak of cellular RA followed by reduction to trace amounts. Treatment with RAG resulted in constantly high cellular RAG and low RA levels. Under the combined RA and retinol treatment retinyl esters were increased and RA was reduced in HaCaT cells, whereas extracellular RA levels were similar to those obtained by RA alone. On the other hand, the combination of RAG and retinol resulted in higher extracellular RAG, similar cellular RAG, and lower cellular RA levels than those obtained by RAG alone without any change in retinyl esters. This study demonstrates that retinoid signaling by RA and RAG is attenuated by simultaneous exposure of HaCaT keratinocytes in vitro to retinol. The presence of retinol in the medium alters the rate of RA or RAG metabolism and thus cellular RA concentrations. The intensity of retinoid signal is probably dependent on cellular RA levels. The resulting "antagonism" among retinoids is consistent with the presence of an auto-regulatory mechanism in human keratinocytes offering protection against excessive accumulation of cellular RA.

Embryonic subcellular distribution of 13-cis- and all-trans-retinoic acid indicates differential cytosolic/nuclear localization.

Isotretinoin (13-cis-retinoic acid [13CRA], Accutane) is used for the treatment of dermatological diseases. Isotretinoin is, however, teratogenic in animals and humans. The mechanism of action of its teratogenicity is still not clearly identified. It has little or no binding properties to cytosolic retinoid-binding proteins or nuclear retinoid receptors (RAR, RXR). One hypothesis is that the teratogenicity of 2 approximately equipotent teratogenic doses of 13CRA and all-trans-retinoic acids (ATRA) could mainly be correlated to ATRA in the nuclei, where the retinoic acid receptors (RARs) are located. To test this hypothesis, female mice at gestational day 11 were treated with approximately equipotent teratogenic doses of 13-cis-retinoic acid (100 mg/kg orally) or all-trans-retinoic acid (10 mg/kg orally) and sacrificed 1 h and 4 h after administration. Embryos were homogenized and centrifuged into 4 fractions, and the purity of the fractions was tested by quantification of marker constituents for various cell compartments. We analyzed, by RP-HPLC, nuclear, mitochondrial, microsomal, and cytosolic fractions, as well as embryo homogenate and maternal plasma. After treatment with 13-cis-retinoic acid, this substance was mainly located in the nuclear fraction of the embryo (approximately 82%), whereas all-trans-retinoic acid, after ATRA treatment, was mainly located in the cytosolic supernatant (approximately 64%). The binding to cellular retinoid-binding protein (CRABP) may limit the access of ATRA to the nucleus, in contrast to 13CRA, which does not bind to CRABP. The concentration of ATRA in the nuclear fraction was similar after administration of either 13CRA or ATRA. The teratogenic activity of 13-cis-retinoic acid could therefore be explained by its access to the nucleus and its possible conversion to all-trans-retinoic acids, which will interact with the nuclear retinoid receptors.

Antiepileptic drugs alter endogenous retinoid concentrations: a possible mechanism of teratogenesis of anticonvulsant therapy.

The major antiepileptic drugs used for the control of seizures can induce developmental toxicity when administered during pregnancy. Vitamin A and retinoids are thought to control many processes of embryonic development including growth, differentiation and morphogenesis. We have therefore studied if the teratogenic action of antiepileptic agents could be mediated via alteration of the endogenous vitamin A--retinoid metabolism. Retinol and its oxidative metabolites all-trans-, 13-cis- and 13-cis-4-oxo-retinoic acid were measured in the plasma of 75 infants and children treated with various antiepileptic drugs for the control of seizures, and in 29 untreated controls of comparable age. Retinol levels increased with age, while the concentrations of retinoic acid compounds did not exhibit age-dependency. Valproic acid monotherapy increased retinol levels in the young age group and a trend toward increased retinol concentrations was also observed in all other patient groups. The plasma levels of the oxidative metabolites 13-cis- and 13-cis-4-oxo-retinoic acids were strongly decreased in all patient groups treated with phenytoin, phenobarbital, carbamazepine and ethosuximide, in combination with valproic acid, to levels which were below 1/3rd and 1/10th of corresponding control values, respectively. Little changes were observed with all-trans-retinoic acid except in one patient group treated with valproic acid/ethosuximide cotherapy where increased levels of this retinoid were found. Our study indicates that therapy with antiepileptic agents can have a profound effect on the endogenous retinoid metabolism. Because of the importance of retinoids for the signaling of crucial biological events during embryonic development, such altered retinoid metabolism may be highly significant in regard to antiepileptic drug teratogenesis.

The enantioselective teratogenicity of 2-n-propyl-4-pentynoic acid (4-yn-VPA) is due to stereoselective intrinsic activity and not differences in pharmacokinetics.

The present study was designed to investigate whether there are pharmacokinetic reasons for the enantioselective teratogenicity of R(+)-4-yn-VPA (low potency) and S(-)-4-yn-VPA (high potency). A gas chromatographic method was employed to determine 4-yn-VPA enantiomers in maternal plasma, brain, erythrocytes and in the embryo and decidua/extraembryonic membranes of the mouse following a single intraperitoneal dose of 300 mg/kg (+/-)-4-yn-VPA-Na on day 9 of gestation. Furthermore, the pharmacokinetics of R- and S-4-yn-VPA were studied in maternal plasma of day-8 pregnant mice following intraperitoneal administration of 300 and 500 mg (+/-)-4-yn-VPA-Na/kg body wt., respectively. No significant difference in the pharmacokinetic profiles of the two enantiomers was detected in either the maternal organism or in the embryonic compartments. Thus, the two enantiomers reach the embryo in comparable concentrations during the sensitive period of organogenesis, but exhibit very different teratogenic activities. This study therefore indicates that the stereoselective teratogenicity of 4-yn-VPA is due to differences in intrinsic activities and not due to differences in the pharmacokinetics of the enantiomers.

Smoking and passive smoking during pregnancy and early infancy: effects on birth weight, lactation period, and cotinine concentrations in mother's milk and infant's urine.

The extent of smoke exposure via mother's milk and passive smoking was investigated in a prospective, longitudinal matched-pair study by comparison between children, whose mothers smoked substantially throughout pregnancy and nursing period and children whose mothers did not smoke. Our preliminary results show that not only infants of smoking mothers but also those of smoking fathers show reduction of birth weight. Smoking mothers weaned their babies earlier than non-smokers. Cotinine concentrations in breast milk depended on the number of cigarettes smoked. The highest urinary excretion of cotinine (as expressed by ng cotinine/mg creatinine ratios) were observed in infants fully breast-fed by smoking mothers. After weaning the values were in the same range as those of formula-fed infants of smoking mothers (exposed to passive smoking only). In the group of non-smokers only small or undetectable amounts of cotinine were found. Thus it is demonstrated that both nursing and--to a lower degree--passive smoking contribute to the exposure of infants to nicotine and its metabolite cotinine.

Lipoyl dehydrogenase activity of erythrocytes in Spielmeyer-Vogt-Batten's disease.

Using the method for the determination of the lipoyl dehydrogenase activity in intact erythrocytes described by Seet and Lee (1975), it was demonstrated that in patients with Spielmeyer-Vogt-Batten's disease, this activity was around the lower limit of normal. In these patients, the enzymatic activity is significantly reduced to such an extent that it may affect the function and metabolism of the erythrocytes.

Lipid peroxidation in platelets from patients with Spielmeyer-Vogt-Batten syndrome.

Platelet lipid peroxidation was studied in normal controls, subjects with epilepsy and patients with the Spielmeyer-Vogt-Batten syndrome. The results showed wide intra- and inter-individual variation, particulary in the latter group. The mean value in Spielmeyer-Vogt-Batten syndrome was not significantly higher than the mean values for the other two groups.

Acid phosphatase activity in lymphocytes from patients with Spielmeyer-Vogt-Batten's syndrome.

The purpose of the investigation presented was to study whether the lymphocytes from patients with Spielmeyer-Vogt-Batten's syndrome deviate from normal with respect to acid phosphatase activity. The distribution of the activity seems to show that the patients with Spielmeyer-Vogt-Batten's syndrome can be divided into two groups, viz. one in which the values are concentrated around the normal level, and another with increased values.

Defective maturation of granulocytes, retinal cysts and multiple skeletal malformations in a mentally retarded girl.

A case of congenital malformations of the extremities (deformed thumbs and great toes, dislocation of the hips, limitation of motion of the joints of the lower extremities), bilateral microphthalmia, bilateral retinal cysts, cerebral atrophy epilepsy, severe physical and mental retardation and monolobed neutrophil granulocytes is reported. A similar clinical picture has not previously been described. We assume that the patient suffers from a sublethal genetic disorder.

Sequences near the termini are required for transposition of the maize transposon Ac in transgenic tobacco plants.

Deletion derivatives of the maize transposable element Activator (Ac) were constructed in vitro and inserted into a kanamycin resistance gene. These constructions were then introduced into tobacco protoplasts derived from plants previously transformed with Ac. The ability of each deletion derivative to excise was measured by whether or not kanamycin-resistant tobacco calli were recovered. This allowed us to determine the length of DNA present at each terminus that is required to respond to the products expressed by the Ac element present in the genome. We show that around 200 base pairs (bp) are required at both ends for excision to occur at wild-type levels. When between 100 and 200 bp were retained at one of the ends, reduced frequencies of excision were detected. With less than 100 bp remaining at either end, no excision was detected. In addition, we show that although similar lengths of DNA are required at each terminus, the termini are not interchangeable. The significance of these data is discussed with respect to the protein(s) which interact(s) with the termini of Ac.

Pneumocystis carinii pneumonia during maintenance treatment of childhood acute lymphoblastic leukemia.

BACKGROUND: Pneumocystis carinii pneumonia (PCP) is a wellknown risk among patients with deficient T-cell function such as children treated for acute lymphoblastic leukemia (ALL). The purpose of this study was to estimate the risk for PCP during maintenance treatment (MT) to identify patients at risk who could benefit from prophylaxis. PROCEDURE: We registered all episodes of PCP during MT in 71 children diagnosed between January 1992 and June 1997 with non-B-cell ALL at The Copenhagen University Hospital. Sulphametoxazole and trimetroprim (SMX/TMP) prophylaxis against PCP was given during induction and consolidation therapy but stopped prior to MT with oral methotrexate/6-mercaptopurine. Patients with standard (SR), intermediate (IR), and high risk (HR) ALL started MT at 3, 8, and 15 months from diagnosis, respectively. RESULTS: The HR group had a cumulated risk of 70% for developing PCP, whereas the risk for PCP in children with IR and the SR was 11 and 8%, respectively (P < 0.0001). All but one of these 13 cases of PCP occurred within 8 months after cessation of SMX-TMP prophylaxis. CONCLUSIONS: The higher incidence of PCP among HR compared to non-HR patients following cessation of SMX/TMP prophylaxis probably reflects the significantly longer T-cell suppressive consolidation therapy in this group. The very low incidence of PCP during the later part of MT emphasizes that methotrexate/6-mercaptopurine MT have more impact on B-cell than on T-cell function. TMP/SMX prophylaxis should be recommended for all children treated for ALL.

Cigarette smoke exposure and development of infants throughout the first year of life: influence of passive smoking and nursing on cotinine levels in breast milk and infant's urine.

The effects of smoke exposure via mothers' milk and/or via passive smoking during the first year of life were investigated in a prospective longitudinal matched-pair study. The somatic and mental development of 69 infants whose mothers smoked more than five cigarettes per day throughout pregnancy and continued smoking after childbirth were compared with 69 children of non-smoking mothers. At birth, mean body weight of neonates from smoking mothers was significantly lower than the weight of neonates from non-smoking mothers. This weight difference between the two groups was no longer significant in infants at 12 months of age. With the methods employed by the authors, neither psychomotor nor mental development was affected by smoke exposure during pregnancy and early infancy. Infections of the lower respiratory tract were more frequent in the children of smoking mothers. These mothers weaned their babies earlier than non-smokers, but the different feeding behaviour did not influence any of the clinical parameters that were investigated in this study. In order to evaluate the extent of smoke exposure, cotinine was measured in children's urine and in breast milk once a month throughout the first year of life. Cotinine in the urine was significantly dependent on feeding behaviour: infants breast fed showed concentrations 10-fold higher than those who were bottle fed. Cotinine excretion in urine of infants from smoking mothers, who were not breast fed (nicotine exposure via passive smoking only) was even higher than that of adult passive smokers. If infants from smoking mothers were breast fed, their urinary cotinine excretion was in the range of adult smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Gbeta gamma mediate differentiation of vascular smooth muscle cells.

Proliferation and subsequent dedifferentiation of vascular smooth muscle (VSM) cells contribute to the pathogenesis of atherosclerosis and postangioplastic restenosis. The dedifferentiation of VSM cells in vivo or in cell culture is characterized by a loss of contractile proteins such as smooth muscle-specific alpha-actin and myosin heavy chain (SM-MHC). Serum increased the expression of contractile proteins in neonatal rat VSM cells, indicating a redifferentiation process. RNase protection assays defined thrombin as a serum component that increases the abundance of SM-MHC transcripts. Additionally, serum and thrombin transiently elevated cytosolic Ca(2+) concentrations, led to a biphasic extracellular signal-regulated kinase (ERK) phosphorylation, up-regulated a transfected SM-MHC promoter construct, and induced expression of the contractile proteins SM-MHC and alpha-actin. Pertussis toxin, N17-Ras/Raf, and PD98059 prevented both the serum- and thrombin-induced second phase ERK phosphorylation and SM-MHC promoter activation. Constitutively active Galpha(q), Galpha(i), Galpha(12), and Galpha(13) failed to up-regulate SM-MHC transcription, whereas Gbetagamma concentration-dependently increased the SM-MHC promoter activity. Furthermore, the Gbetagamma scavenger beta-adrenergic receptor kinase 1 C-terminal peptide abolished the serum-mediated differentiation. We conclude that receptor-mediated differentiation of VSM cells requires Gbetagamma and an intact Ras/Raf/MEK/ERK signaling.

Metabolism of topical retinaldehyde and retinol by mouse skin in vivo: predominant formation of retinyl esters and identification of 14-hydroxy-4, 14-retro-retinol.

We have previously shown that retinaldehyde (RAL), a natural metabolite of beta-carotene and retinol (ROL), can be used topically in human skin and exerts biological activity; it may be a convenient way to deliver multipotential vitamin A activity in epidermis. RAL can be converted enzymatically into 2 pathways: one leads to ROL (and then retinyl esters), the other to retinoic acid (RA). The aim of the present study was 2-fold: (i) to see if RAL is metabolised in vivo when topically applied on mouse skin, and (ii) if so, to analyse the occurrence and relative importance of the 2 metabolic pathways as compared to ROL. We studied by HPLC the metabolites detectable in mouse tail skin upon topical application of RAL and ROL. As compared to vehicle-treated controls, RAL-treated mouse skin contained low amounts of all-trans RA and 13-cis-RA, whereas ROL content increased 10-fold and retinyl esters 30-fold after RAL application. As compared to RAL, ROL-treated mouse skin showed no detectable RA, slightly less retinyl esters but a significant amount of 14-hydroxy-4, 14-retro-ROL (14-HRR), a metabolite not previously reported in the skin. 14-HRR was the predominant polar metabolite of ROL. These data indicate that keratinocytes metabolise topical RAL, thus confirming the concept of using RAL as a precursor. Both pathways are used but in significantly different proportions. Thus, only a low proportion of RAL is metabolised into all-trans-RA, which may explain the low irritancy profile of topical RAL and supports the concept of a controlled delivery of ligands. That keratinocytes predominantly channel RAL into storage forms indicates that RAL should also be considered as a convenient way to load the epidermis with vitamin A. The detection of 14-HRR, a metabolite not previously reported in skin, that promotes growth of B Iymphocytes and activation of T Iymphocytes, suggests distinct potentials of topical ROL and RAL.

Stereoselective distribution of the teratogenic thalidomide analogue EM12 in the early embryo of marmoset monkey, Wistar rat and NMRI mouse.

Thalidomide administration during early gestation results in specific and dramatic limb defects in primates, but not in laboratory rodents such as the rat and mouse. The thalidomide analogue EM12 [2-(2,6-dioxopiperidine-3-yl)-phthalimidine] was used in the present study because this compound is metabolically more stable and teratogenically more potent than thalidomide in the monkey. We have administered the pure enantiomers, since we have previously shown that S-EM12 proved to be much more teratogenic in the monkey than R-EM12. In maternal plasma, placenta and embryo of the pregnant marmoset monkey (Callithrix jacchus) and Wistar rat, the concentrations were investigated of the enantiomers and their metabolites after administration of R- and S-EM12. With whole body autoradiography the distribution in the embryo, including the target tissue, the embryonic limb bud was examined in the NMRI mouse and marmoset monkey. Our investigations showed that both the R- and the S-enantiomers were transferred to the embryo during organogenesis [monkey, gestation day (GD) 61; rat, GD 12; mouse, GD 10]. The gestation period chosen was toward the end of the thalidomide-sensitive stage, but yielded sufficient gestational material for analysis. Considerable amounts of the enantiomers were produced via racemization of the administered pure enantiomers and were present in maternal plasma as well as in placenta and embryo. In the monkey, the racemization were stereoselective: the S-enantiomer was eliminated more slowly in the monkey than the R-enantiomer, possibly because of stereospecific binding and metabolism. In the plasma and embryo of both rat and monkey, the metabolites were detected in considerably lower concentrations than EM12, emphasizing the importance of the parent drug in regard to the teratogenic effect. The whole-body autoradiography in marmoset and mouse showed high radioactivity in the embryonic CNS, the branchial apparatus and in the limb buds. The S-enantiomer of EM12 was more strongly concentrated than the R-enantiomer in these areas. In the limb buds, the highest concentrations of radioactivity were observed in the periphery, sometimes at the very tip of the buds. Accumulation of radioactivity in limb buds and neural epithelium relative to other areas of the embryo was much more pronounced in the monkey than in the mouse. Future studies must demonstrate if this accumulation has implications for the mechanism of thalidomide teratogenesis in primate species.

Topical 9-cis-retinaldehyde for delivery of 9-cis-retinoic acid in mouse skin.

The 9-cis-retinoic acid (9cRA) is an endogenous ligand of retinoid X nuclear receptors (RXRs). Although the epidermis contains five times more RXRs than RARs, little is known on the activity of topical 9cRA. In order to circumvent surface isomerization of topically applied 9cRA into all-trans-retinoic acid (atRA), we used topical 9-cis-retinaldehyde (9cRAL) as a precursor of 9cRA, hypothesizing that keratinocytes would metabolize 9cRAL into 9-cis-retinoic acid (9cRA). Retinoid content was determined by HPLC analysis of mouse tail skin that had been washed after the application of 9cRAL (0.05% for 14 days) to evaluate the metabolites produced within the epidermis. Biologic activities of 9cRAL and atRAL were analysed by assessing hyperplastic and metaplastic responses, by determining epidermal thickness and the levels of mRNAs encoding for specific keratins. atRAL and derived retinoids were found in skin treated with either atRAL or 9cRAL. The metabolite pattern obtained with 9cRAL was similar to that obtained with atRAL except the presence in 9cRAL samples of an unidentified nonpolar metabolite. However, treatment with 9cRAL yielded higher atRAL and lower retinyl ester concentrations. The biologic activities (hyperplastic and metaplastic responses) resulting from topical application of 9cRAL were lower than those induced by atRAL or atRA at similar concentrations. Taken together, these data show that topical 9cRAL does not deliver significant amounts of 9cRA and exerts less biologic activity than atRAL. Contrary to atRAL, 9cRAL does not appear therefore as a pertinent candidate for topical use in humans.