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Biomedical subjects

A Theron

Publications and source records attributed to A Theron.

At least 37 records · Page 2Linked to original sources
PubMed1981

In vitro and in vivo stimulation of neutrophil migration and lymphocyte transformation by thiamine related to inhibition of the peroxidase/H2O2/halide system.

The effects of thiamine on neutrophil functions and mitogen-induced lymphocyte transformation were investigated in vitro and in vivo in adult volunteers following the injection of 50 mg thiamine intramuscularly. Thiamine caused stimulation of neutrophil motility in vitro and in vivo and increased lymphocyte transformation in vivo. Enhancement of these functions was related to inhibition of neutrophil post-phagocytic iodination of Candida albicans by the MPO/H2O2/halide system. The horseradish peroxidase/-H2O2/125 I-mediated iodination of bovine serum albumin was also inhibited by thiamine concentrations which caused increased neutrophil motility. It was found that preincubation of neutrophils and lymphocytes with the horseradish peroxidase/H2O2/halide system caused considerable inhibition of the migratory and proliferative responses respectively. Inclusion of thiamine at concentrations which were found to inhibit the peroxidase/-H2O2/halide system protected the neutrophil migratory and lymphocyte proliferative responses from inactivation by this system. It is suggested that thiamine may cause increased neutrophil migration and lymphocyte transformation by protecting these cells from toxic oxidative products generated by the peroxidase/H2O2/halide system.

Adult↗
PubMed1980

The effect of ascorbate on cellular humoral immunity in asthmatic children.

Ten White children with bronchial asthma and exercise-induced bronchoconstriction were assessed immunologically before and 1, 3 and 6 months after the commencement of standard therapy supplemented with ascorbate 1 g/d. The tests of cellular immune function were neutrophil chemotaxis, phagocytosis and resting and stimulated nitroblue tetrazolium reduction, and lymphocyte mitogen-induced transformation. Humoral functions measured were secretory IgA, serum immunoglobulins, alpha 1-antitrypsin, C3, C4 and total haemolytic complement, antistreptolysin O (ASO) and C-reactive protein. Radio-allergosorbent testing to the common allergens Cynodon dactylon (grass), Dermatophagoides pteronyssinus (mite), house dust and cat epithelium was performed on each child before and 3 and 6 months after treatment. Two children had depressed neutrophil motility, 4 had depressed lymphocyte transformation, and 7 had elevated levels of ASO. These functions normalized after 6 months of ascorbate-supplemented therapy. Serum total IgE levels but not specific IgE levels were likewise reduced after 6 months of therapy. Reduced levels of serum alpha 1-antitrypsin were observed in 2 children, and remained unchanged throughout the study.

Antibody Formation↗
PubMed1980

[Evaluation of the drift of cercariae by a single daily sampling in the site of schistosomiasis transmission. Example of Guadeloupean sites of Schistosoma mansoni transmission (author's transl)].

Research on cercarian density in running water transmission sites of intestinal schistosomiasis in Guadeloupe has allowed the construction of a representative model of the rhythm of presence of Schistosoma mansoni cercariae. This model allows, with a single daily sampling between 11 a.m. and 2 p.m., the evaluation of the daily sum of hourly densities. We propose to measure the parasite component of the risk of contamination in a bilharzial site by the drift of cercariae expressed in cercariae/day. The drift of cercariae takes account of variations in cercarian density and of the flow of the channel. It expresses the daily quantity of cercariae available for human contamination.

Animals↗
PubMed1980

The effects of increasing weekly doses of ascorbate on certain cellular and humoral immune functions in normal volunteers.

Certain functions of the blood neutrophils and lymphocytes from normal adult volunteers were evaluated after the ingestion of increasing doses of ascorbate. Serum immunoglobulins and levels of C'3 and total hemolytic complement were also measured. Enhancement of neutrophil motility to a chemotactic stimulus of endotoxin-activated autologous serum was observed in normal adult volunteers after the ingestion of 2 and 3 g ascorbate daily. No alteration was observed at lower doses. Other neutrophil functions evaluated that remained unaltered by ascorbate, were postphagocytic hexose monophosphate shunt activity and myeloperoxidase mediated iodination of ingested protein. Stimulation of lymphocyte transformation to the mitogens phytohaemagglutinin and concanavalin A was detected after the daily ingestion of 1, 2, and 3 g of ascorbate. Mitogen-induced protein synthesis was unaffected. Serum levels of IgG, IgA, IgM, C'3, and C'4 and total complement activity were unaltered by ascorbate.

Adult↗
PubMed1980

Effects of sulfamethoxazole and trimethoprim on human neutrophil and lymphocyte functions in vitro: in vivo effects of co-trimoxazole.

The effects of sulfamethoxazole and trimethoprim individually and in combination on in vitro neutrophil random migration, chemotaxis to autologous endotoxin-activated serum and the synthetic chemotactic tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine, phagocytosis and postphagocytic Nitro Blue Tetrazolium reduction, glycolysis, hexose monophosphate shunt activity, myeloperoxidase-mediated protein iodination, hydrogen peroxide production, and degranulation were assessed. The effects on lymphocyte mitogen-induced transformation were also evaluated. It was found that the test agents individually and in combination at high concentrations (> 100 microgram/ml) caused the inhibition of neutrophil postphagocytic myeloperoxidase-mediated protein iodination, which was related to the interference with H2O2 formation as the enzyme per se was unaffected. Both agents caused the inhibition of lymphocyte transformation at high concentrations (> 100 microgram/ml). In vivo studies before and after the ingestion of co-trimoxazole by three individuals showed no inhibition of any of the neutrophil functions tested. The inhibition of lymphocyte transformation was observed in one individual after the ingestion of the chemotherapeutic agent. These findings indicate that the concentrations which inhibit neutrophil H2O2 production and lymphocyte transformation in vitro are not attainable in vivo.

Adult↗
PubMed1980

Demonstration of several sporocysts generations as a normal pattern of reproduction of Schistosoma mansoni.

A thorough study of the development of Schistosoma mansoni demonstrates that asexual reproduction within the vector-mollusc does not proceed according to the usually accepted process. Under natural conditions, daughter sporocysts are capable fo stopping production of cercariae and orienting production towards an additional generation of sporocysts, which themselves will be able to evolve in the same manner. This process intervenes without exception provided that the duration of parasitosis exceeds 40 days (at 26 degrees C). It is observed in three different american strains of S. mansoni. We believe that this is the first demonstration of the existence of several sporocysts generations as an habitual mode of reproduction in the life cycle of Digenea.

Animals↗
PubMed1979

Effects of ascorbate on leucocytes: Part III. In vitro and in vivo stimulation of abnormal neutrophil motility by ascorbate.

Abnormal in vitro neutrophil motility was found in 10 patients with recurrent bacterial infection. The defect appeared to be primary in 3 patients, secondary to hyperimmunoglobulinaemia E in 2 patients and secondary to bacterial infection in 5 patients. In 7 patients impaired polymorphonuclear leucocyte (PMN) motility was the only detectable abnormality; defective lymphocyte function was found in 2 patients and 1 had a total IgA deficiency. Increased random motility and migration to endotoxin-activated serum (EAS) and partially purified C5a was observed when patients' neutrophils were incubated with 5 x 10(-2)M calcium ascorbate or 10(-1)M sodium ascorbate in the presence of 5% autologous serum in vitro. Six of the patients, 4 children and 2 adults, were given oral ascorbate, 1 g daily for children and 3 g daily for adults, and tests of neutrophil migration were performed at monthly intervals thereafter. Improved neutrophil motility was observed in all patients and this correlated with clinical improvement in 5 of the 6.

Adult↗
PubMed1979

Effects of ascorbate on leucocytes: Part I. Effects of ascorbate on neutrophil motility and intracellular cyclic nucleotide levels in vitro.

A preliminary series of experiments indicated that ascorbic acid and calcium and sodium ascorbate in the absence of serum had no stimulatory effect on neutrophil motility. However, when neutrophils were pre-incubated with ascorbate at concentrations between 5 X 10(-2)M and 1 X 10(-1)M in the presence of fresh normal autologous serum (5% final concentration) considerable stimulation of random motility and migration towards the leuco-attractants C5a and casein was observed. The serum factor required for ascorbate-mediated enhanced locomotion was heat unstable and was probably not serum albumin since no stimulation of cell migration was observed when serum was replaced with varying amounts of human serum albumin. Calcium ascorbate was the most potent stimulant of neutrophil motility. Concentrations of calcium and sodium ascorbate which increased migration promoted elevation of intracellular cyclic guanosine monophosphate (cGMP) levels, but not of adenosine monophosphate (cAMP). These same concentrations also caused increased glyclytic activity. It is suggested that the enhanced neutrophil motility mediated by ascorbic acid and calcium and sodium ascorbate in the presence of serum may be due to increased cGMP and/or glycolysis.

Ascorbic Acid↗
PubMed1979

Effects of metronidazole on certain functions of human blood neutrophils and lymphocytes.

The effects of metronidazole at varying concentrations (10(-7)M - 10(-2)M) on certain cellular immune functions were assessed in vitro. Neutrophil chemotaxis to endotoxin-activated autologous serum, random motility and postphagocytic metabolic activity (hexose monophosphate shunt activity, myeloperoxidase-mediated protein iodination and glycolysis) were unaffected. Likewise, metronidazole had no detectable effects on lymphocyte-active E-rosette formation, mitogen-induced DNA synthesis and mitogen-induced protein synthesis.

Blood Proteins↗
PubMed1979

A differential filtration technique for the measurement of schistosome cercarial densities in standing waters.

The technique of differential filtration allows the detection of schistosome cercariae, with a recovery greater than 80%, in natural waters with a high concentration of microorganisms. This technique makes use of a new type of monofilament polyamide filter Nytrel-TI, with a pore size of 40 mum, allowing filtration of turbid water without clogging of the filter. A three-level prefiltration column (1000, 500 and 200 mum), which retains organisms larger than cercariae, facilitates reading of the filter. The apparatus used weighs less than 3.5 kg; it requires no power supply and can easily be used in the field.

Animals↗
PubMed1979

The in vitro evaluation of certain neutrophil and lymphocyte functions following the ingestion of 150 mg oral dose of levamisole: assessment of the extent and duration of stimulation of neutrophil chemotaxis, protein iodination and lymphocyte transformation.

Certain functions of human blood neutrophils and lymphocytes were investigated at varying time intervals after the ingestion of a single 150 mg dose of levamisole. The functions tested were neutrophil chemotaxis and post-phagocytic metabolic activity and mitogen-induced DNA and protein synthesis of lymphocytes. It was found that levamisole causes a stimulation of neutrophils motility (cell- and serum-associated) and post-phagocytic hexose monophosphate shunt activity and protein iodination. Increased lymphocyte DNA synthesis, but not protein synthesis, to the mitogen phytohaemagglutinin was observed. The stimulation which was detected almost immediately of these neutrophil and lymphocyte functions was still evident 24 hr later but not at 48 hr, indicating that a single oral dose of levamisole can cause the alteration (stimulation) of leucocyte functions which persists until 24--48 hr after intake of the drug.

Chemotaxis, Leukocyte↗
PubMedDate not supplied

[The life cycle of Gorgoderina rochalimai Pereira and Cuocolo, 1940, a Digenea parasite of Bufo marinus in Guadeloupe].

The sporocysts of G. rochalimai were found in Guadeloupe, in the bivalve Mollusc Sphaeriidae Eupera viridans. The cystocercous cercariae are ingested by Odonatan larvae in which the encystement occurs. The Toad Bufo marinus is the definitive host of the parasite. The life-cycle of G. rochalimai shows close similarities with the ones already known in many other speicies of Gorgoderidae.

Animals↗
PubMedDate not supplied

[The life cycle of Plagiorchis neomidis Brendow, 1970, digenean parasite of Neomys fodiens in the Pyrénées. Chronobiology of cercarial emergence (author's transl)].

The first host in the life cycle of Plagiorchis neomidis in the Pyrenees is the Mollusc Radix limosa var, glacialis. The cercariae encyst in the aquatic larvae of the Insect Sialis lutaria (Megaloptera). The adult parasite is found in the rectum of Neomys fodiens. The chetotaxy and the rhythm of cercarial emergence are described in detail as is the development of the metacercaria in its second intermediate host. Comparison of the life cycle of P. neomidis in the Pyrenees with that described in Germany demonstrates differences in the biology at both larval and adult stage.

Animals↗