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Biomedical subjects

J F Charles

Publications and source records attributed to J F Charles.

At least 55 records · Page 3Linked to original sources
PubMed1991

Two novel strains of Bacillus thuringiensis toxic to coleopterans.

Two novel strains of Bacillus thuringiensis were isolated from native habitats by the use of genes coding for proteins toxic to coleopterans (cryIII genes) as hybridization probes. Strain EG2838 (isolated by the use of the cryIIIA probe) contained a cryIIIA-hybridizing plasmid of approximately 100 MDa and synthesized crystal proteins of approximately 200 (doublet), 74, 70, 32, and 28 kDa. Strain EG4961 (isolated by the use of a cryIIIA-related probe) contained a cryIIIA-hybridizing plasmid of approximately 95 MDa and synthesized crystal proteins of 74, 70, and 30 kDa. Structural relationships among the crystal proteins of strains EG2838 and EG4961 were detected; antibodies to the CryIIIA protein toxic to coleopterans reacted with the 74- and 70-kDa proteins of EG2838 and EG4961, antibodies to the 32-kDa plus 28-kDa proteins of EG2838 reacted with the 30-kDa protein of EG4961, and antibodies to the 200-kDa proteins of EG2838 reacted with the 28-kDa protein of EG2838. Experiments with B. thuringiensis flagella antibody reagents demonstrated that EG2838 belongs to H serotype 9 (reference strain B. thuringiensis subsp. tolworthi) and that EG4961 belongs to H serotype 18 (reference strain B. thuringiensis subsp. kumamotoensis). A mixture of spores plus crystal proteins of either EG2838 or EG4961 was toxic to the larvae of Colorado potato beetle (Leptinotarsa decemlineata), and significantly, the EG4961 mixture was also toxic to the larvae of southern corn rootworm (Diabrotica undecimpunctata howardi). DNA restriction blot analysis suggested that strains EG2838 and EG4961 each contained a unique gene coding for a protein toxic to coleopterans.

Animals↗
PubMed1991

Deletion by in vivo recombination shows that the 28-kilodalton cytolytic polypeptide from Bacillus thuringiensis subsp. israelensis is not essential for mosquitocidal activity.

The cytA gene encoding the 28-kDa polypeptide of Bacillus thuringiensis subsp. israelensis crystals was disrupted in the 72-MDa resident plasmid by in vivo recombination, thus indicating that homologous recombination occurs in B. thuringiensis. The absence of the 28-kDa protein in B. thuringiensis did not affect the crystallization of the other toxic components of the parasporal body (68-, 125-, and 135-kDa polypeptides). The absence of the 28-kDa protein abolished the hemolytic activity of B. thuringiensis subsp. israelensis crystals. However, the mosquitocidal activity of the 28-kDa protein-free crystals did not differ significantly from that of the wild-type crystals when tested on Aedes aegypti and Culex pipiens larvae. The 28-kDa protein contributed slightly to the toxicity to Anopheles stephensi larvae. This indicates that the 28-kDa protein is not essential for mosquitocidal activity, at least against the three species tested.

Animals↗
PubMed1991

[Mucus-secreting tumors of the appendix: a preoperative diagnosis is possible. Apropos of 2 cases].

The authors present two cases of pseudo tumoral type Mucus Secreting Tumours (MST) of the appendix. In this type (32% of the cases), the clinical presentation, barium enema, ultrasonography and most importantly CT scan generally confirm the preoperative diagnosis. We found three advantages this preoperative diagnosis. 1) Primarily it allow selection of a large surgical approach that permits full exploration of the abdominal cavity especially the ovaries (2-18% associated lesions); 2) also it allows a histopathological examination (frozen section) of the appendix to be performed during the operation; 3) and finally the surgical treatment will depend on the operative findings and the result of the histopathological examination: in the benign forms simple appendicectomy will be sufficient but the malignant forms (12% of the cases) should be treated by right hemicolectomy.

Appendiceal Neoplasms↗
PubMed1991

[Mucus-secreting tumors of the appendix: a preoperative diagnosis is possible. Apropos of 2 cases].

The authors present two cases of pseudo tumoral type Mucus Secreting Tumours (MST) of the appendix. In this type (32% of the cases), the clinical presentation, barium enema, ultrasonography and most importantly CT scan generally confirm the preoperative diagnosis. We found three advantages this preoperative diagnosis. 1) Primarily it allows selection of a large surgical approach that permits full exploration of the abdominal cavity especially the ovaries (2-18% associated lesions); 2) also it allows a histopathological examination (frozen section) of the appendix to be performed during the operation; 3) and finally the surgical treatment will depend on the operative findings and the result of the histopathological examination: in the benign forms simple appendicectomy will be sufficient but the malignant forms (12% of the cases) should be treated by right hemicolectomy.

Appendectomy↗
PubMed1990

Role of the gut proteinases from mosquito larvae in the mechanism of action and the specificity of the Bacillus sphaericus toxin.

Gut proteinases from larvae of mosquito species both susceptible and not susceptible to Bacillus sphaericus converted the 43-kDa toxin to a 40-kDa polypeptide exhibiting enhanced cytotoxicity to mosquito cell cultures. The toxin was also activated by gut proteinases from the nonsusceptible Lepidoptera Spodoptera littoralis in vitro and in vivo. Therefore, the specificity of Bacillus sphaericus toxin does not seem to be determined by gut proteinase action. However, susceptibility of mosquito cell cultures did not reflect the specificity of the toxin, which must now be investigated at the cellular level in the larvae.

Aedes↗
PubMed1990

[Clostridium bifermentans serovar malaysia, a new anaerobic bacterium pathogen to mosquito and blackfly larvae].

A strain of Clostridium bifermentans individualized as serovar malaysia (C.b.m.) according to its specific H antigen is toxic to mosquito and blackfly larvae when given orally. The toxicity occurs in sporulated cells which contain, in addition to spores, proteinic parasporal inclusion bodies and feather-like appendages; the amino acid content of the inclusion bodies is similar to that of Bacillus thuringiensis serovar israelensis (B.t.i.) and B. sphaericus crystals. The toxicity to Anopheles stephensi is as high as that of B.t.i. and the best strains of B. sphaericus. Culex pipiens is somewhat less susceptible, and Aedes aegypti much less. Pure parasporal inclusion bodies, isolated by ultracentrifugation on sucrose gradients, are highly toxic to mosquito larvae. The larvicidal power is destroyed by heating at 80 degrees C or by treatment with 50 mM NaOH. It is preserved by freeze-drying. The innocuity to mice of the sporulated cells is shown by different routes of administration: force-feeding, percutaneous, subcutaneous, intraperitoneal or intravenous injections. The potential for the biological control of mosquito and blackfly larvae is suggested.

Animals↗
PubMed1987

Peripheral blood and tumor-infiltrating mononuclear cell analysis in esophagus and head and neck cancer.

We show a significantly decreased number of OKT3+ lymphocytes in the peripheral blood (PB) of cancer patients mainly due to a reduced number of OKT4 cells. OKT8 cells were also somewhat reduced. The numbers of DR+ and interleukin-2 receptor-bearing T-cells were significantly increased in patients. The tumor-infiltrating cells included OKT4+ AND OKT8+ lymphocytes. There was a significant correlation between the proportion of activated T-cells in PB and in tumor, as shown by DR and interleukin-2 receptor expression.

Adult↗
PubMed1987

[Ultrasound-guided percutaneous ureterostomy].

The authors present a new technique for percutaneous insertion of a drain into the upper urinary tract, using the direct lumbar transureteric approach under ultrasonographic control. This ultrasound-guided percutaneous ureterostomy was performed in two patients to drain the upper urinary tract and to evaluate the adjacent renal parenchyma. In both cases, ureterostomy was preferred to nephrostomy because of the difficulties of performing the latter operation and because of the considerable dilatation of the ureter.

Adult↗
PubMed1987

[Adenocarcinoma of the duodenum. Apropos of 2 cases: review of the literature].

The authors report two cases of duodenal adenocarcinoma. Review of literature has permitted them to conclude the rarity of the lesion which among malignant tumours of the small intestine, is the gommenest. Localization of the tumour in the periampullary area in 47% of cases rendered it difficult to differentiate from ampullary and pancreatic tumours especially with the unknown etiological factors (with exception to villous tumours which has a 35% rate of malignant transformation), and also with unspecific symptoms. Diagnosis by x-ray and endoscopy has an accuracy rate of more then 85%. Prognosis is bad and depend mainly on histological differentiation and lymph node spread. 5 years survival rate of 40-50% can be achieved by curative surgery namely cephalic duodeno-pancreatectomy in cases with no lymph node involvement.

Adenocarcinoma↗
PubMed1985

[Zinc in the human prostate].

The quantities of zinc naturally present in prostatic epithelial cells determine the human prostate to be a zinc-rich gland. Since the growth of the prostate depends on androgenic steroid hormones, interrelationships between steroids and zinc were investigated. It appears now that zinc in hyperplastic prostates is bound to cytoplasmic citrate. Metabolic homeostasia in prostatic secretory cells may be insured by inhibition of cis-aconitase by free zinc and its binding to accumulating citrate. The yields of bound zinc are decreased by androgenic steroids (testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol) which increase in turn the levels of free zinc, the uptake and the reduction of testosterone and citrate accumulation. In dedifferentiated hormono-independent neoplastic cells, there is less reduction of testosterone and a drastic decrease in zinc levels due to the sole presence of a metallothionein for binding.

Cell Nucleus↗
PubMed1984

Testosterone metabolism by homogenates of human prostates with benign hyperplasia: effects of zinc, cadmium and other bivalent cations.

The effects of various quantities of Ba, Be, Ca, Cd, Co, Cu, Mg, Mn, Sr, Zn and EDTA on the formation of 5 alpha-reduced metabolites of testosterone (T) substrate and of 3 alpha-/3 beta-reduced metabolites of 5 alpha-dihydrotestosterone substrates by homogenates of 6 human hyperplastic prostate glands were studied in incubations at pH 7.4 with NADPH-generating system. Effects of these cations and EDTA on the VM and KM of the 5 alpha-reductase and 3 alpha-/3 beta-hydroxysteroid dehydrogenases (-HSD) were also measured. Quantities of 5 alpha-reduced T metabolites were significantly increased by Cd, Cu and Zn supplementations. These increments were shown to result from significant augmentations of the VM but no change in KM of the NADPH-dependent 5 alpha-reductase. Quantities of 3 alpha-reduced DHT metabolites were significantly decreased by Cd and Cu supplementations and resulted from an increase of the KM of the NADPH-dependent 3 alpha-HSD by Cd and both an increase of KM and a decrease of VM by Cu. Quantities of 3 beta-reduced DHT metabolites were significantly decreased by Cd and Cu supplementations. Increase of the KM of the NADPH-dependent 3 beta-HSD by Cd was found significant while Cu both increased the KM and decreased the VM of the enzyme. EDTA-related changes in 5 alpha-reductase activity were shown to result from the EDTA-induced decrease of the pH of the medium. No effect of EDTA was observed on the activities of both 3 alpha/3 beta-HSD.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1984

Sporulation of Bacillus sphaericus 2297: an electron microscope study of crystal-like inclusion biogenesis and toxicity to mosquito larvae.

Sporulation of Bacillus sphaericus strain 2297 in a synchronous liquid culture was studied by electron microscopy. The t0 of sporulation occurred 7 h after the beginning of the lag phase. Crystal-like inclusions first appeared at t2 and reached their final size between t5 and t6. The release of the spore/inclusion complex occurred at about t15 (22 h after inoculation). Toxicity against Culex pipiens larvae was related to sporulation and appeared during the early stages of sporulation. The LC50 (24 h) decreased about 10(5)-fold between t0-2 and t7, in correlation with the formation of crystalline inclusions. Heat resistance of spores appeared later than toxicity.

Animals↗