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Biomedical subjects

A Berry

Publications and source records attributed to A Berry.

At least 19 recordsLinked to original sources
PubMed2006

In vitro and in vivo antiplasmodial activity of Momordica balsamina alone or in a traditional mixture.

BACKGROUND: Because of the dramatic situation of malaria in Africa, there is an urgent need to find new and cheap drugs, such as herbal medicines. Here we report the study of the in vitro and in vivo antimalarial activity of Momordica balsamina alone or in a traditional mixture used in Niger. METHODS: Extracts were obtained with different solvents and tested in vitro on Plasmodium falciparum and in vivo on Plasmodium vinckei. RESULTS: The best extracts are methanolic and present promising results in vivo by intraperitoneal and oral administration. CONCLUSION: The antimalarial activity of M. balsamina, traditionally used in Niger, is confirmed in vitro and in vivo without any toxicity in healthy mice.

Animals↗
PubMed2006

Scedosporium apiospermum mycetoma with bone involvement successfully treated with voriconazole.

Treatment of Scedosporium apiospermum mycetoma usually requires limb amputation. A 49-year-old woman, from Ivory Coast, was diagnosed with Madura foot in 1995. She failed to respond to several treatments including itraconazole, fluconazole and co-trimoxazole, and refused limb amputation. In December 2002 she was admitted to hospital in France with a painful, swollen right leg and foot. She had no fever and C-reactive protein was 120 mg/l. Magnetic resonance imaging (MRI) confirmed the destruction of tarsus bones with a tibia extension. Voriconazole (400 mg/day) treatment was initiated in March 2003; a significant clinical improvement was observed within 4 months as confirmed by C-reactive protein (16 mg/l) and MRI. Voriconazole was maintained for 18 months with good tolerance. Cholestasis appeared after the first month and remained stable. In October 2004 voriconazole was discontinued due to side effects on the liver (alanine aminotransferase 17 times the normal level); MRI showed impressive regression of bone lesions. As of July 2005, the patient remains clinically well. Voriconazole appears to be a promising drug for the treatment of S. apiospermum mycetomas.

Antifungal Agents↗
PubMed2006

Pneumocystis jirovecii genotypes and granulomatous pneumocystosis.

This study describes the initial data concerning molecular typing of Pneumocystis jirovecii in a patient having developed granulomatous Pneumocystis pneumonia (PCP). Three types, B(1)a(3), B(1)a(4), B(1)b(2), were identified. All three had been described in reports concerning patients with common diffuse alveolar PCP. The present data show that identical microorganisms can be involved in both granulomatous PCP and diffuse alveolar PCP and that the pathogenesis of the granulomatous response to P. jirovecii may more likely be related to host factors.

Bacterial Typing Techniques↗
PubMed2006

Comparison between two amplification sets for molecular diagnosis of toxoplasmosis by real-time PCR.

PCR is now commonly applied to the diagnosis of toxoplasmosis. Although several methods are available, comparative studies are few, making it difficult to compare the performance of each technique. We compared the sensitivities of two real-time PCR assays through a prospective study on fetuses, neonates, and immunocompromised patients and on the ocular diagnosis of toxoplasmosis. The first system targeted the widely used B1 gene (GenBank accession number AF179871) while the second (RE) targeted a more recently described sequence repeated roughly 200 to 300 times (GenBank accession number AF146527). We demonstrated that molecular diagnosis requires the duplication of PCR assays, especially with the B1 system, as only one PCR was positive in 33.3% of cases. Our study showed that the RE target was more sensitive for all biological samples (amniotic fluid, placenta, aqueous humor, whole blood, and cerebrospinal and bronchoalveolar fluids) and significantly improved the performance of the diagnosis of toxoplasmosis. Taking into consideration all clinical samples, the mean gain in the crossing point value was 4.2 +/- 1.7 cycles and was even more significant for amniotic fluid (5.8 +/- 1.7 cycles).

Amniotic Fluid↗
PubMed2005

In vitro antiplasmodial activity of 18 plants used in Congo Brazzaville traditional medicine.

Sixty-six extracts of 18 plants commonly used by traditional healers in Congo Brazzaville for the treatment of malaria have been investigated for in vitro antiplasmodial activity. Ethanolic and dichloromethane extracts of 7 among the 18 studied plants were moderately active (10 microg/ml<IC(50)<50 microg/ml). These extracts concerned Cassia siamea (bark), Cogniauxia podolaena (root), Landolphia lanceolata (root and leaves), Millettia versicolor (leaves), Pseudospondias microcarpa (leaves), Uapaca paludosa (leaves) and Vernonia brazzavillensis (leaves). These results support their traditional use as antimalarial plants. The bark extract of Uapaca paludosa showed a good activity (<10 microg/ml) and the extracts from Quassia africana (root and leaves) even exhibited IC(50) values less than 1 microg/ml. Except for Quassia africana, for which the three solvents (water, ethanol and dichloromethane) present an effective extraction, no aqueous extract was highly active. The cytotoxicity of aqueous, DCM and ethanol extracts of Quassia africana was tested on KB cell lines.

Antimalarials↗
PubMed2005

Low doses of dexamethasone can produce a hypocorticosteroid state in the brain.

The synthetic glucocorticoid dexamethasone (dex) blocks stress-induced hypothalamic-pituitary-adrenal (HPA) activation primarily at the level of the anterior pituitary because multidrug resistance P-glycoprotein hampers its penetration in the brain. Here, we tested the hypothesis that central components of the HPA axis would escape dex suppression under conditions of potent peripheral glucocorticoid action. We subchronically treated rats with low or high doses of dex. The animals were subjected on the last day of treatment for 30 min to a restraint stressor after which central and peripheral markers of HPA axis activity were measured. Basal and stress-induced corticosterone secretion, body weight gain, adrenal and thymus weight, as well as proopiomelanocortin mRNA in the anterior pituitary were reduced in a dose-dependent manner by dex administered either 5 d sc or 3 wk orally. In the brain, the highest dose dex suppressed CRH mRNA and CRH heteronuclear RNA in the paraventricular nucleus (PVN). However, in the peripherally active low-dose range of dex CRH mRNA and heteronuclear RNA showed resistance to suppression, and CRH mRNA expression in the PVN was in fact enhanced under the long-term treatment condition. In the PVN, c-fos mRNA was suppressed by the highest dose of dex, but this effect showed a degree of resistance after long-term oral treatment. c-fos mRNA responses in the anterior pituitary followed those in PVN and reflect central drive of the HPA axis even if corticosterone responses are strongly reduced. The results support the concept that low doses of dex can create a hypocorticoid state in the brain.

Administration, Oral↗
PubMed2005

Structure-guided saturation mutagenesis of N-acetylneuraminic acid lyase for the synthesis of sialic acid mimetics.

Analogues of N-acetylneuraminic acid (sialic acid, NANA, Neu5Ac), including 6-dipropylcarboxamides, have been found to be selective and potent inhibitors of influenza sialidases. Sialic acid analogues are, however, difficult to synthesize by traditional chemical methods and the enzyme N-acetylneuraminic acid lyase (NAL) has previously been used for the synthesis of a number of analogues. The activity of this enzyme towards 6-dipropylcarboxamides is, however, low. Here, we used structure-guided saturation mutagenesis to produce variants of NAL with improved activity and specificity towards 6-dipropylcarboxamides. Three residues were targeted for mutagenesis, Asp191, Glu192 and Ser208. Only substitution at position 192 produced significant improvements in activity towards the dipropylamide. One variant, E192N, showed a 49-fold improvement in catalytic efficiency towards the target analogue and a 690-fold shift in specificity from sialic acid towards the analogue. These engineering efforts provide a scaffold for the further tailoring of NAL for the synthesis of sialic acid mimetics.

Amides↗
PubMed2005

An alternative method for Plasmodium culture synchronization.

Since the synchronization of Plasmodium falciparum has become an essential tool in research, we have investigated the use of a commercial gelatine solution, Plasmion, to replace Plasmagel, which is now difficult to obtain. This method also avoids the use of techniques based on Percoll-glucose gradients. The Plasmion-based technique proved to be a good method and could become an alternative to Plasmagel.

Animals↗
PubMed2005

Diagnosis of infectious canine hepatitis virus (CAV-1) infection in puppies with encephalopathy.

Nine weaned Labrador Retriever puppies from a litter of 11 were presented with signs of acute central nervous system (CNS) disease that included ataxia and blindness. All puppies died. Gross examination of tissues from 2 puppies revealed regionally diffuse hemorrhages in the brain stem and swollen hemorrhagic lymph nodes. Light microscopic examination of hematoxylin and eosin-stained tissues showed numerous large, basophilic intranuclear inclusion bodies within CNS vascular endothelium and occasionally in individual hepatocytes. Immunohistochemical staining of the tissue was positive using an antibody against canine adenovirus-1. Virus isolation for infectious canine hepatitis virus was achieved using inoculated cell cultures. Polymerase chain reaction amplification of DNA from cell culture material revealed shared homology with other mammalian adenoviruses.

Animals↗
PubMed2005

Ex vivo and in vitro impairment of CD36 expression and tumor necrosis factor-alpha production in human monocytes in response to Plasmodium falciparum-parasitized erythrocytes.

Severe malaria is associated with the failure of host defenses to control parasite replication, with the excessive secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), and with the sequestration of parasitized erythrocytes (PEs) in the microcirculation of vital organs. The scavenger receptor CD36, known as a major sequestration receptor, has also been identified as an important factor in mediating nonopsonic phagocytosis of PEs by monocytes and macrophages. The specific consequence of this phagocytosis is a decrease in parasite-induced TNF-alpha secretion. We evaluated the variations in CD36 level and in lipopolysaccharide (LPS)-induced TNF-alpha production in monocytes from Plasmodium falciparum-infected patients and in vitro in the presence of PEs. Both the monocytes from infected patients and from in vitro culture showed a decrease of CD36 expression and a reduced production of TNF-alpha induced by LPS. Using incubation assays with no contact between monocytes and PEs, or in the presence of a soluble supernatant obtained from the incubation of monocytes and PEs, this study shows that decreased CD36 expression was posttranscriptional and not directly related to PEs phagocytosis. In addition, these culture models suggest that the reduced capacity of TNF-alpha production occurred in 2 phases. The early phase (24 hr) appeared to be CD36 dependent and the second phase (48 hr) was due to a soluble factor produced by PEs. These observations suggest that the control of the TNF-alpha production in malaria by monocytes was not entirely dependent on the phagocytosis of PEs by CD36 and that soluble factors produced by PEs could play a role in this process.

Animals↗
PubMed2005

Glucocorticoids suppress macrophage migration inhibitory factor (MIF) expression in a cell-type-specific manner.

MIF is a potent proinflammatory cytokine involved in inflammatory arthritis. Glucocorticoids (GC) have been reported to induce secretion of MIF in rodent cells, and as MIF counteracts the anti-inflammatory effects of GC, this has implications for human inflammatory disease. Transient transfection studies showed that the MIF promoter was repressed by dexamethasone (Dex) (10 nM) in CEM C7A cells, with up to 50% suppression by 100 nM. However, there was no regulation of the promoter by GC in A549 cells. We also found that subnanomolar concentrations of Dex suppressed MIF secretion, measured by ELISA, by 80% in both human T lymphoblasts (CEM C7A) and human lung epithelial cells (A549). Endogenous MIF mRNA was also repressed by GC in CEM C7A cells, measured both by Northern blot and quantitative RT-PCR assays, but there was no such regulation in A549 cells. This suggests that GC affects translation rather than transcription of MIF in A549 cells. These results contradict earlier results with the rat cell line RAW 264.7. Therefore, we analysed MIF secretion from RAW 264.7 cells but found no GC effect on secretion. Understanding how GC regulates MIF in a cell-type-dependent manner may give insights into GC-refractory human inflammatory diseases.

Animals↗
PubMed2005

Contribution of PCR-based methods to diagnosis and management of imported malaria.

Since the first description, in 1990, of the diagnosis of Plasmodium falciparum infection by polymerase-chain-reaction (PCR), the role of this kind of molecular method in laboratory diagnosis of imported malaria is still a topical question. Various molecular assays have been used, the first of which was hybridization using labeled probes in 1984. When compared to thick blood smear, this test displayed a sensitivity ranging from 65% to 81% and specificity was close to 100%. The next technical improvement was the introduction of the so-called polymerase chain reaction (PCR), the principle of which was described in 1985. In 1993, a PCR-based assay detecting all four Plasmodium species was published, followed by different variants of this method. By the turn of the century, novel real-time PCR slashed workaround time, which dropped from 2 1/2 hours to less than 1 hour. Moreover, automatic reading with no human action on PCR products reduced the risks of contamination. The first application of real-time PCR to the diagnosis of malaria was published in 2001. PCR-based assays were found to be more sensitive than all conventional methods. Variations in sensitivity were probably due to different medical practices as well as to the proportion of various types of subjects (travelers under chemoprophylaxis, immigrants from malaria-endemic areas) in the population undergoing malaria diagnosis. The target of the primers was also of crucial importance: for the detection of P. falciparum, the most efficient assays amplified either the gene SSUrRNA, or Pf155/RESA, or Cox 1. Specificity of PCR results is guaranteed by the nature of the target for primers or probes, as determined by the studies of the Plasmodium genome whose results are available in GenBank. PCR use often corrected the results of Plasmodium species identification by microscopy and PCR-based methods were found to be the most efficient for the detection of mixed infections. Concerning the diagnosis of imported malaria, it appears clearly that PCR should be considered as second-line method which can be especially interesting, as a negative result rules out malaria in febrile patients. However, the use of PCR assays appears to be restricted to health centers, such as University Hospitals, for whom malaria identification is an important and routine problem. In the future, the detection of mutations related to drug resistance could be used to orient anti-malarial therapy.

Automation↗
PubMed2004

Directed evolution of enzymes for biocatalysis and the life sciences.

Engineering the specificity and properties of enzymes and proteins within rapid time frames has become feasible with the advent of directed evolution. In the absence of detailed structural and mechanistic information, new functions can be engineered by introducing and recombining mutations, followed by subsequent testing of each variant for the desired new function. A range of methods are available for mutagenesis, and these can be used to introduce mutations at single sites, targeted regions within a gene or randomly throughout the entire gene. In addition, a number of different methods are available to allow recombination of point mutations or blocks of sequence space with little or no homology. Currently, enzyme engineers are still learning which combinations of selection methods and techniques for mutagenesis and DNA recombination are most efficient. Moreover, deciding where to introduce mutations or where to allow recombination is actively being investigated by combining experimental and computational methods. These techniques are already being successfully used for the creation of novel proteins for biocatalysis and the life sciences.

Catalysis↗
PubMed2004

Comparative assessment of conventional PCR with multiplex real-time PCR using SYBR Green I detection for the molecular diagnosis of imported malaria.

For the diagnosis of imported malaria, optical or immunochromatographic methods are known to be less sensitive and less specific than PCR-based methods, which are conversely more complicated and time-consuming. An original strategy, based upon the sequential use of a multiplex competitive real-time PCR detecting Plasmodium falciparum or Plasmodium spp. infection, followed by, if necessary, a single real-time PCR for species identification, was therefore performed and then tested versus conventional PCR in routine conditions. Conventional PCR has been used since October 1999 in the Department of Parasitology, University Hospitals in Toulouse, as a 2nd line diagnostic method. Out of 183 patients tested, 48 were found to be harbouring a falciparum infection by conventional microscopy, 60 by conventional PCR and 60 by multiplex competitive real-time PCR. Nine further patients had a non-falciparum infection, and concordant species identifications were obtained by both conventional PCR and single real-time PCR. The major value of PCR-based methods, when compared to microscopical techniques, was to ascertain the negativity of a suspect sample. Moreover, real-time PCR allows simplification of the operating procedure, with a diagnosis being made within 2 h.

Animals↗
PubMed2004

Busulphan given as four single daily doses of 150 mg/m2 is safe and effective in children of all ages.

We examined the effects of busulphan (BU) dose and patient age on toxicity and outcome in 63 children with acute leukaemia given BUCY prior to allogeneic or autologous BMT. BU was administered as four single daily oral doses, based either on weight (4 x 4 mg/kg) or surface area (4 x 150 mg/m2). BU pharmacokinetic analysis was not used to dose adjust. The average daily (mg/kg) BU dose was 43% higher for the group given 150 mg/m2 compared to the 4 mg/kg dose group. This produced a median BU AUC 61% higher than with the 4 mg/kg dose. Only one child did not achieve full allogeneic donor engraftment. Regimen-related toxicity was low. Although younger children had faster BU clearance, the 4 x 150 mg/m2 dose ensured equivalent systemic exposure to BU, and resulted in a high frequency of engraftment without a significant increase in serious toxicity. BU, given as four single daily doses of 150 mg/m2, is appropriate and safe in all age groups of children. Given the reliable pharmacokinetics, low toxicity and high rate of allogeneic engraftment, there is no need for routine pharmacokinetic monitoring or dose modifications. This dosage regimen may be applicable for use with i.v. BU.

Bone Marrow Transplantation↗
PubMed2003

[Oral histoplasmosis 34 years after return of Africa].

INTRODUCTION: Histoplasmosis is a tropical fungal infection sharing many similarities with tuberculosis: the transmission by air dropplets, the usually asymptomatic primary-infection, the disseminated infection encountered among immunosuppressed patients and the granulomatous pathological lesions. In France, histoplasmosis is uncommon and may be misdiagnosed as tuberculosis. OBSERVATION: A 78 years old male patient presents with a raspberry-like lesion of the mouth causing difficulties to eat and weight loss of 14 kg. The diagnosis of tuberculosis is evoked because of the presence of a giant-cell granuloma in one of the biopsies. The histoplasmosis serology, requested because the patient stayed in Africa, is positive. Revisions of the pathology put into evidence the presence of spores in histiocytes confirming diagnosis of histoplasmosis. The treatment with itraconazole is effective. CONCLUSION: Histoplasmosis is a differential diagnosis of tuberculosis, especially in endemic regions. The histoplasmosis serology can be useful. The reference in diagnosis examinations keeps being the microscopic observation of spores and their mycological growth.

Africa↗