Biomedical subjects
Publications and source records attributed to F Roblot.
The trunk bark and roots of Annona spinescens have been investigated for their alkaloid content. Two new berbine alkaloids, pessoine (1) and spinosine (2), have been isolated from the bark, and their structures were elucidated by spectroscopic methods. Eight known isoquinoline alkaloids were also obtained. The trypanocidal and antileishmanial activities of these isolated compounds have been investigated.
The authors report the case of a woman affected by disseminated infection caused by Mycobacterium bovis, without risk exposure and immunodeficiency. There were chest and urinary localisations and bacteremia. Usually, M bovis is responsible of chest tuberculosis, in patients with professional exposure. Disseminated forms usually affect patients with immunodeficiency. Bacteria may be responsible of about 1% of tuberculosis, but real frequency is not known, because of its non specific report.
Datura stramonium is a hallucinogenic plant found in urban or rural areas. It contains three main toxic alkaloids: atropine, scopolamine, and hyosciamine. Consumption of any part of the plant can result in severe anticholinergic toxicity. Clinical symptoms are those seen in atropine poisoning, particularly hallucinations and mydriasis. Prognostic is good in this study. Patients always require hospitalisation because of agitated behavior. Symptomatic treatment is efficient. Clinicians should be aware of the potential abuse of botanicals such as jimson weed to avoid excessive investigations.
A petroleum ether extract of Peperomia galoides showed significant in vitro activity against three Leishmania species and Trypanosoma cruzi. Three major prenylated diphenols, including two known compounds, grifolic acid [1], and grifolin [2], and the new substance piperogalin [3], have been isolated. Structures were established on the basis of spectral analysis including 2D nmr spectroscopy.
Rifampin is an enzymatic inducer known to increase steroid metabolism. We studied two patients with giant cell arteritis in whom rifampin caused nonresponsiveness to prednisone treatment. A prednisone pharmacokinetics study was done. When rifampin-prednisone treatment must be used in giant cell arteritis, we propose increasing the prednisone dosage to 2 mg/kg per day.
Four new alkaloids were obtained from Guatteria foliosa, namely, the noraporphines (-)-3-methoxyputerine [1] and (+)-norguattevaline [2], the more highly oxidized (+)-3-methoxyguattescidine [3], and the oxoaporphine 3-methoxyoxoputerine [4]. Among several other known alkaloids also found in this same plant, (-)-3-hydroxynornuciferine, (-)-isoguattouregidine, and argentinine exhibited significant activity against Trypanosoma cruzi.
The stem bark of Ampelocera edentula Kuhlm. (Ulmaceae) is used by the Chimanes Indians from Bolivia for the treatment of cutaneous leishmaniasis caused by the protozoan Leishmania braziliensis. A chloroform extract of the stem barks was found to be active against extracellular forms of Leishmania ssp. and Trypanosoma cruzi at 50 micrograms/ml. Bioassay-guided fractionation of this extract allowed us to isolate one active compound. Its structure was elucidated by spectral and chemical studies as 4-hydroxy-1-tetralone. BALB/c mice infected with L. amazonensis (PH8) or L. venezuelensis were treated one day after the parasitic infection with 4-hydroxy-1-tetralone (25 mg/kg/day) or with reference drug, Glucantime (56 mg Sbv/kg/day) for 14 days. Lesion development was the criteria used to evaluate the disease severity. 4-Hydroxy-1-tetralone was slightly less effective than the reference drug against L. amazonensis or L. venezuelensis. Single treatment near the site of infection, 14 days after infection with L. amazonensis, with 4-hydroxy-1-tetralone (50 mg/kg) was more effective than Glucantime (112 mg/kg). This study is, to our knowledge, the first to show the activity of a tetralone for the experimental treatment of New World cutaneous leishmaniasis.
Botulism, a food-borne toxin-mediated disease caused by Clostridium botulinum is still a common disease, which is most frequent in the rural environment; 108 cases, 66 males and 42 females, average age 32 years, were recorded from 1965 to 1990 in the infectious disease department of the University Hospital of Poitiers (France). In 83% of patients, the food responsible was home-cured ham. Mean incubation time was 3.4 days; digestive symptoms were observed in 93% of cases, ocular symptoms in 92% and urinary tract dysfunction in 22%. A scale of severity was used to classify the patients into those suffering from severe (6), intermediate (50) and mild (52) forms of the disease. Botulinum toxin type B was found in 36 (52%) of 69 blood samples and in 41 (51%) of 81 samples of the suspected food. From 1965 to 1976, 44 patients were treated with both toxoid and heterologous equine serotherapy. Since 1976, 29 patients have been treated with guanidine hydrochloride (35 mg/kg daily) and 35 patients with guanidine hydrochloride plus heterologous serotherapy. All 108 patients recovered without any sequelae.
A retrospective study of ten cases of intoxication due to Datura were reported. Clinical symptoms were those of atropinic intoxication, associated with hallucinations and aggressiveness. The diagnostic is supported by clinical examination. Laboratory examinations are useful only for differential diagnosis.
Forty-seven patients were included in a prospective trial to define the interest for searching immunologic abnormalities during endocarditis. No specific abnormalities were found, aside some patients with endocarditis who have a high levels of immune complexes. These results suggest that the interesting immunologic abnormality is the presence of an high level of immune complexes could be of interest in endocarditis.
The stem barks of Pera benensis are employed by the Chimane Indians in the Bolivian Amazonia as treatment of cutaneous leishmaniasis caused by the protozoan Leishmania braziliensis. The chloroform extracts containing quinones were found active against the promastigote forms of Leishmania and the epimastigote forms of Trypanosoma cruzi at 10 micrograms ml-1. The activity guided fractionation of the extract by chromatography afforded active compounds. Their structures were elucidated, by spectral and chemical studies, as known naphthoquinones, plumbagin, 3,3'-biplumbagin, 8-8'-biplumbagin, and triterpene, lupeol. The activity in vitro of each compound was evaluated against 5 strains of Leishmania (promastigote), 6 strains of Trypanosoma cruzi (epimastigote) and the intracellular form (amastigote) of Leishmania amazonensis. The baseline drugs used were Glucantime and pentamidine (Leishmania spp.), nifurtimox and benznidazole (T. cruzi). Plumbagin was the most active compound in vitro. This study has demonstrated that Pera benensis, a medicinal plant used in folk medicine, is an efficient treatment of cutaneous leishmaniasis.
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Fluoroquinolones are antibiotics that act principally on DNA gyrase. At the moment, resistance to these antibiotics is purely chromosome-mediated. As regards pharmacokinetics, these compounds have a high bioavailability and penetrate extremely well into tissues and cells. Therapeutic concentrations are obtained in bronchial mucosa and lung tissue. In severe lower respiratory tract infections fluoroquinolones must be given in combination with other antibiotics to prevent the emergence of resistant mutants. The indications of fluoroquinolones in lower respiratory tract infections depend on their antibacterial spectrum. They are particularly useful in the treatment of infections caused by methicillin-sensitive or resistant staphylococci, Pseudomonas spp. (notably in cystic fibrosis) and intracellular organisms. They are not indicated for streptococcal infections, notably those due to Streptococcus pneumoniae, and for anaerobic infections. Fluoroquinolones are currently used mainly in hospital-acquired lower respiratory tract infections, in infected cystic fibrosis and in some acute episodes of chronic bronchitis since they are active against Haemophilus influenzae and Branhamella catarrhalis.
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