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Biomedical subjects

L Fransen

Publications and source records attributed to L Fransen.

At least 37 records · Page 2Linked to original sources
PubMed1995

Syphilis control in pregnancy: decentralization of screening facilities to primary care level, a demonstration project in Nairobi, Kenya.

A decentralized syphilis control program in pregnant women was implemented in nine Nairobi City Council antenatal clinics between July 1992 and August 1993, whereby pregnant women were screened for syphilis, treated before leaving the clinic if RPR seroreactive, and counselled on the importance of partner treatment and sexual abstinence during treatment in order to protect their unborn babies from getting congenital syphilis. A total of 13,131 pregnant women were screened for syphilis (RPR test), 87.3% of seroreactive women were treated on site and 50% of partners returned to the clinic and were treated. The prevalence of RPR reactivity was 6.5%. Based on other data the program could theoretically have prevented 413 cases of congenital syphilis at a cost of approximately 50 USD per prevented case. This demonstration project shows that decentralized prevention of congenital syphilis in antenatal clinics by nurses is feasible and inexpensive and should receive priority in resource allocation in reproductive health and child survival programs.

Female↗
PubMed1995

STD/HIV prevention in Turkey: planning a sequence of interventions.

This study was initiated to assess which mix of early STD/HIV prevention interventions would potentially be effective, cost-effective and sustainable in Turkey; and to program an intervention sequence to maximize synergy among the interventions. During rapid assessment we: 1) reviewed past issues of 3 leading newspapers; 2) collected information on TV coverage; 3) interviewed key informants including taxicab drivers, hotel employees, grocery store owners, academicians in public health and law, investigators of STD/HIV and reproductive tract infections, and officials in the ministry of health; 4) reviewed available evidence on STD/HIV morbidity, sexual behavior patterns, migration patterns and same/opposite gender sex trade. We found: 1) discrepancies between decision makers' perceptions and social realities with respect to the epidemiology of sexual behavior and STDs, and the state of public health programs; 2) discrepancies between sexual practices and public expression regarding sexual practices; 3) economic, demographic, and political pressures in Turkey and in surrounding countries for the expansion of prostitution; 4) a sexual double standard and gender specific migration patterns which sustain a high demand for commercial sex; 5) patterns of health care seeking behaviors and provision of STD clinical services which indicate other STDs may play a very important role in spread of HIV infection; 6) an important mass media role in opinion formation; 7) consensual denial of risk for the majority based on beliefs embedded in machismo, nationalism and religion, and a resulting marginalization and externalization of STD/HIV risk; 8) high prevalence of syphilis among both Turkish and immigrant female prostitutes in Istanbul (early latent 8 and 13%; late latent 0 and 4%; previous history 9 and 22%) 9) and high rates of syphilis among male prostitutes (early latent 11%, late latent 21% and previous history 58%). We concluded that interventions should initially include, in the following order; 1) awareness raising for decision makers and opinion leaders including members of parliament and mass media; 2) awareness raising for members of the general population; 3) needs assessment and intervention development for sex workers; 4) training in HIV and other STDs for medical personnel; and 5) quality assurance and control for laboratory procedures for STDs/HIV.

Female↗
PubMed1994

Characterization of a rat C6 glioma-secreted follistatin-related protein (FRP). Cloning and sequence of the human homologue.

A protein was isolated from rat C6 glioma-conditioned medium and was biochemically characterized. The heparin-binding protein has a native molecular mass of 55-75,000 Da, a molecular mass of 40-48,000 Da under denaturing conditions, and a pI of 5.0-6.0. Based on the determined partial amino acid sequences, the full lenght cDNA encoding the rat and human proteins were cloned. The cDNA sequences identified the isolated rat and human protein as the homologue of a recently reported mouse osteoblast-transforming-growth-factor-beta 1-inducible protein, encoded by the TSC-36 gene [Shibanuma, M., Mashimo, J., Mita, A., Kuroki, T. & Nose, K. (1993) Eur. J. Biochem. 217, 13-19]. Analysis of the human, rat and mouse amino acid sequences indicates that these proteins are highly conserved (> 92% sequence identity). Sequence similarities with follistatin and the follistatin-like domain of agrin are revealed. The relationship with follistatin and agrin points to possible common functions for the cloned follistatin-related proteins (FRP). The protein has no effect on the inhibitory action of transforming growth factor-beta 1, on CCl-64 cell growth.

Agrin↗
PubMed1994

Mapping the lectin-like activity of tumor necrosis factor.

Tumor necrosis factor (TNF), but not lymphotoxin (LT), is directly trypanolytic for salivarian trypanosomes. This activity was not blocked by soluble 55-kilodalton and 75-kilodalton TNF receptors, but was potently inhibited by N,N'-diacetylchitobiose, an oligosaccharide that binds TNF. Comparative sequence analysis of TNF and LT localized the trypanocidal region, and synthetic peptides were trypanolytic. TNF molecules in which the trypanocidal region was mutated or deleted retained tumoricidal activity. Thus, trypanosome-TNF interactions occur via a TNF domain, probably with lectin-like affinity, which is functionally and spatially distinct from the mammalian TNF receptor binding sites.

Amino Acid Sequence↗
PubMed1992

IFN-gamma-induced L-arginine-dependent toxoplasmastatic activity in murine peritoneal macrophages is mediated by endogenous tumor necrosis factor-alpha.

Activated murine peritoneal macrophages inhibit the intracellular proliferation of Toxoplasma gondii and produce a number of cytokines, such as TNF-alpha and IL-1. Both TNF-alpha and IL-1 have been reported to be involved in the immune response against various microorganisms, but the mechanisms responsible for these effects are not known. In the present study it was investigated whether endogenously produced TNF-alpha and IL-1 are involved in the activation of peritoneal macrophages by rIFN-gamma leading to toxoplasmastatic activity and the production of reactive nitrogen intermediates. The rIFN-gamma-induced toxoplasmastatic activity was inhibited by neutralizing antibodies against mouse TNF-alpha in a dose-dependent and time-dependent way, but neutralizing antibodies against mouse IL-1 alpha and IL-1 beta did not affect this activity. Involvement of TNF-alpha in the induction of toxoplasmastatic activity was confirmed by our finding that rTNF-alpha in combination with a nonactivating concentration of rIFN-gamma inhibited the intracellular proliferation of T. gondii. No synergistic activity of rIL-1 and rIFN-gamma on the inhibition of T. gondii proliferation was found. Both rTNF-alpha and rIL-1 alpha alone inhibited the intracellular proliferation of T. gondii only slightly. Because it has been reported recently that activated macrophages produce reactive nitrogen intermediates that are essential in the induction of toxoplasmastatic activity, we investigated whether these intermediates are involved in the TNF-dependent induction of toxoplasmastatic activity. Neutralizing antibodies against mouse TNF-alpha inhibited also the release of NO2- by rIFN-gamma-activated macrophages almost completely. Macrophages incubated with rTNF-alpha in combination with a nonactivating concentration of rIFN-gamma released substantial amounts of NO2-, but rTNF-alpha and rIL-1 alpha alone, and the combination of rIL-1 alpha and a nonactivating concentration of rIFN-gamma induced only little NO2(-)-release by macrophages. To assess whether reactive nitrogen intermediates act directly or indirectly on the intracellular proliferation of T. gondii, macrophages were incubated with the L-arginine analog NG-monomethyl-L-arginine or the NADPH-inhibitor diphenylene iodonium, both inhibitors of the generation of reactive nitrogen intermediates. Good correlation was found between toxoplasmastatic activity and the release of NO2- during the 24-h activation period before infection of the macrophages with T. gondii, but no correlation was found between toxoplasmastatic activity and the release of NO2- during infection of the macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

The provision of safe blood--policy issues in the prevention of human immunodeficiency virus transmission.

The AIDS epidemic has focused attention on the constraints and deficiencies present in many blood transfusion services in the developing world. We discuss a variety of options for reducing transfusion-related HIV transmission, and suggest how new transfusion strategies may be implemented. We show that a transfusion service cannot rely solely on the screening of donor blood for anti-HIV antibodies and that a more comprehensive approach is needed. Important components of this approach include donor selection and improved clinical practice, in which blood and blood products are prescribed only when really necessary.

Biological Products↗
PubMed1990

Poly I:C activated macrophages are tumoricidal for TNF-alpha-resistant 3LL tumor cells.

Successive coculture of Lewis lung carcinoma (3LL) cells with T cell-derived lymphokines and LPS-activated macrophages has led to the acquisition of 3LL tumor variants (macrophage-resistant 3LL tumor variants (3LL-R)), manifesting a highly reduced sensitivity to the cytotoxic potential of T cell-derived lymphokines and LPS-activated macrophages and TNF-alpha. However, when 3LL-R cells are cocultured with Poly I:C-activated macrophages or with conditioned medium derived from these effector cells a significant lysis is observed. TNF-alpha participates in the cytolytic process of Poly I:C-activated macrophages as anti-TNF-alpha antibodies abolish the cytotoxic effect of these effector cells. In addition, class I IFN is involved because IFN-alpha and IFN-beta act synergistically on TNF-alpha mediated lysis of 3LL-R cells within 18 h. Moreover, anticlass I IFN antibodies abolish the cytolytic capacity of Poly I:C-activated macrophages. Hence, Poly I:C-induced macrophage-mediated cytolysis of 3LL-R cells may result from 1) the induction of macrophages by Poly I:C to secrete high amounts of TNF-alpha and class I IFN and 2) a synergism between IFN-alpha/IFN-beta and TNF-alpha on lysis of 3LL-R cells. This synergism does not result from a class I IFN-mediated enhancement of TNF-alpha receptor expression on 3LL-R cells. Therefore, the sensitivity of 3LL-R cells to TNF-alpha-mediated lysis in the presence of class I IFN is most probably regulated at the post-TNF-alpha receptor level. Furthermore, treatment of mice with Poly I:C strongly reduces the metastatic capacity of 3LL-R tumor cells, suggesting the participation of macrophages in the eradication of the established metastasis. Hence, TNF-alpha-resistant 3LL-R tumor cells may serve as a useful tool for the detection of alternative macrophage-related cytotoxins leading to the destruction of neoplastic cells both in vitro and in vivo.

Animals↗
PubMed1990

Expression and processing of the activin-A/erythroid differentiation factor precursor: a member of the transforming growth factor-beta superfamily.

The biosynthesis and intracellular processing of the polypeptide precursor of the beta A-chain of the fertility hormone inhibin were assessed by infecting a wide spectrum of cell types with a recombinant vaccinia virus. Most cell lines, including follicular granulosa cells, secrete both prohormone and mature hormone as homodimers (activin) composed of disulfide-linked subunits of 54 kDa (proactivin-A) and 14 kDa (activin-A), respectively, and a small amount of prohormone-mature hormone heterodimers. Mature activin is secreted from mouse pituitary cells (AtT-20), while pig kidney cells [PK(15)] secrete mostly proactivin. More prohormone is secreted in the presence of NH4Cl, suggesting that prohormone processing is facilitated by low pH. Proactivin-A is not a ligand for the mannose-6-phosphate/insulin growth factor-II receptor. The recombinant activin stimulates FSH release from pituitary cells and differentiates erythroleukemia cell lines in vitro.

Acetylglucosaminidase↗
PubMed1990

[Sexually transmitted diseases in the female population of Pikine, Senegal].

The prevalence of some sexually transmitted disease is determined in 250 gynaecology patients and in 200 pregnant women seen in primary health centers in Pikine, Senegal. The main reason for consultation at gynaecology is infertility. Gonorrhoea and Chlamydia trachomatis infection are present respectively in 1.5% and 7% of pregnant women and in 4.4% and 7.6% of gynaecology patients. Human papillomavirus infection, determined by DNA extraction and hybridization technique, is seen in 4% of obstetric and in 1.2% of gynecology patients. Cytological anomalies is found in 5.5% of pregnant women and in 4.8% of gynecology patients.

Adult↗
PubMed1988

Neonatal ophthalmia in the developing world. Epidemiology, etiology, management and control.

In the 19th century, the incidence of neonatal conjunctivitis varied between 1 and 14% in Europe, and the disease was a main cause of blindness at that time. Since then the epidemiology of ophthalmia neonatorum (ON) has changed and Chlamydia trachomatis is more frequent than Neisseria gonorrhoeae. Both are still very common causes of ON in the developing world. ON can not be differentiated clinically as to the etiology, but Intracellular Gram Negative Diplococci (IGND) on a Gram stain of an eye smear has an excellent validity and further differentiation can be made using microbiological cultures. All cases of presumed gonococcal conjunctivitis must be treated with effective systemic antibiotics. Systemic treatment with penicillin can still be used in areas where the percentage of beta-lactamase producing strains of gonococci is very low. For other areas a single dose of ceftriaxone intramuscular combined with saline eye washes is the treatment of choice. Chlamydial ON necessitates also systemic treatment with erythromycin. Parents of infants with gonococcal or chlamydia ON also need to be examined and treated. Prevention of gonococcal and chlamydial disease can be done following 3 strategies: antenatal diagnosis and treatment of maternal infections or disinfection of the infants eyes at birth or adequate treatment of infants and parents as soon as a ON has been diagnosed. Crédé's eye prophylaxis with silver nitrate has become a controversial issue, because of concern about the occurrence of chemical conjunctivitis and its ineffectiveness against infections with C. trachomatis.(ABSTRACT TRUNCATED AT 250 WORDS)

Chlamydia Infections↗
PubMed1988

Thymopentin treatment in genital warts of long duration.

The immunomodulatory effect of thymopentin as therapy in genital warts of long duration and the proliferative responses of the patient's peripheral blood mononuclear cells were investigated in this pilot study. The observations in 6 patients suggest that subcutaneous injections of thymopentin (50 mg) beneficially influence the systems of therapy-resistant genital warts. The small number of patients and controls used in the assessment of the proliferation responses allows only a descriptive analysis of the results, but definitive trends can be observed in the Con A- and PHA-induced proliferation tests. These clinical observations, the theoretical considerations, and the low rate of side effects of thymopentin reported also by other investigators all emphasize the importance of further well-controlled double-blind studies on the treatment of genital warts with thymopentin.

Adult↗
PubMed1987

Incidence and bacterial aetiology of neonatal conjunctivitis.

Two hundred and twenty-nine infants born consecutively at the maternity ward of the Middelheim Hospital in Antwerp, over a period of 5 months, and an additional 55 randomly selected infants born at the same hospital were clinically and microbiologically investigated before leaving the maternity ward. All infants born at this maternity ward received argyrol eye drops immediately after birth. Twenty-six (11%) of the infants consecutively investigated had neonatal conjunctivitis diagnosed before leaving the maternity ward, where they stayed from 7-10 days. Another 29 infants were reported to have developed sticky eyes and/or red eyes after leaving the maternity hospital and before 1 month of age. The instantaneous risk of developing, a conjunctivitis was equal for each day of the first month of life. Chlamydia trachomatis was isolated from the eyes of 11 of the 229 (4.8%) consecutively born infants but only one had conjunctivitis symptoms before leaving the maternity ward. Overall one or more bacterial species could be isolated from the eyes of 143 (48%) of the infants, but only viridans streptococci and Staphylococcus aureus were cultured significantly more often from the eyes of cases with conjunctivitis than from the eyes of the infants without conjunctivitis (P less than 0.001).

Bacteria↗
PubMed1987

Single-dose ceftriaxone for chancroid.

Men with genital ulcers that were culture positive for Haemophilus ducreyi were treated with intramuscular ceftriaxone and randomized to three different dose regimens. All but 1 of 50 men treated with 1 g of intramuscular ceftriaxone were cured. Similarly, 0.5 and 0.25 g cured 43 of 44 men and 37 of 38 men, respectively. A single dose of 250 mg of intramuscular ceftriaxone is an effective treatment for chancroid.

Adult↗
PubMed1986

Treatment of genital chlamydial infection with ofloxacin.

42 men and women with a genital chlamydial infection were randomly treated with a single dose of 200 mg doxycycline daily for ten days or with 200 mg ofloxacin twice a day for nine days. Two weeks after starting treatment 40 patients were able to be reassessed. All 12 men and all seven women treated with doxycycline had clinically improved or healed and had negative cultures for Chlamydia trachomatis. Among the patients treated with ofloxacin, all 11 males had improved or healed and C. trachomatis was not reisolated. These data are promising but larger numbers of patients and a longer follow-up are needed in order to confirm the efficacy of ofloxacin for the treatment of genital chlamydial infections.

Adolescent↗
PubMed1986

Recombinant tumor necrosis factor: species specificity for a variety of human and murine transformed cell lines.

Tumor necrosis factor (TNF) exhibits cytotoxic or cytostatic activity on a wide range of animal and human transformed cell lines. Using pure, recombinant human and mouse TNF, we examined the degree of species specificity of the in vitro TNF activity on a variety of human and murine transformed cell lines. This species specificity was studied for the TNF activity alone or in synergism with IFN-gamma. Recombinant human and mouse TNF behave remarkably similarly regarding the in vitro cytolytic/cytostatic activity. However, a certain degree of species-specific preference could be revealed as human cell lines needed a higher concentration of recombinant mouse TNF than of recombinant human TNF to attain a similar effect, while on mouse cells the reverse was true. Also, synergism with IFN-gamma seemed more effective when the target cell was treated with homologous TNF.

Animals↗
PubMed1986

Recombinant tumor necrosis factor: its effect and its synergism with interferon-gamma on a variety of normal and transformed human cell lines.

Tumor Necrosis Factor (TNF), released by induced macrophages, causes tumor necrosis in animals, and preferentially kills transformed cells in vitro. Using pure, recombinant human TNF, we report here its cytotoxic action on several human transformed and non-transformed cell lines. Furthermore, remarkable synergism between TNF and interferon-gamma (IFN-gamma) was observed in a large number of human cell lines, especially breast, cervix and colon carcinomas. Some other human cell lines, not sensitive to TNF alone, became highly sensitive when IFN-gamma was present as well. We could not demonstrate a synergism between TNF and IFN-gamma on any of the lymphoma/leukemia cell lines tested. All normal human, non-transformed diploid cell lines were insensitive to TNF even in the presence of IFN-gamma. This study also confirms the observation that inhibition of protein synthesis by metabolic drugs (e.g. actinomycin D) remarkably enhances the sensitivity of several target cell lines to cytolysis by TNF.

Cell Division↗