Development of the human immune response against the major surface protein (gp190) of Plasmodium falciparum

The 190-kilodalton glycoprotein (gp190) of Plasmodium falciparum, the precursor of the major surface proteins of merozoites, is considered a promising candidate for a blood stage malaria vaccine. DNA sequences specific for the gp190 of the two isolates K1 and MAD20 were subcloned and expressed in Escherichia coli. The panel of fusion proteins obtained represents about 80% of the polymorphic sequences observed so far within various isolates of P. falciparum. Sera from individuals living in a malaria-endemic area of West Africa were tested in immunoblots against the gp190 fusion proteins, and antibody reactivity was mapped to defined regions of the gp190. Depending on the age of the individual and on the presence of parasites in the blood, distinct regions of gp190 were differentially recognized by the respective antibodies. Similarly, the analysis of sera from German patients with acute malaria revealed a distinct pattern. When grouped according to age and to parasitemia, the reactivity of the sera of people living in malaria-endemic areas may indicate a correlation between certain gp190 regions and protective immune response.

Interference of manganese on neuroendocrinal system in exposed workers. Preliminary report

The neurotoxic effects of Manganese (Mn) are well known, and are usually caused by high occupational exposure over long periods of time. The effects caused by low doses of this metal have been poorly evaluated. For this reason, we decided to evaluate neuroendocrinal tests in a group of 14 male workers employed in a ferrous-manganese foundry (exposed to Mn air concentrations within the TLV-TWA) and in 14 male control subjects, by analyzing FSH, LH, prolactin, and cortisol. The urinary Mn; prolactin, and cortisol levels were significantly higher in the worker's group. The preliminary results of this research seem to show that for exposure below the TLV, Mn can somehow interfere with the neuroendocrine system. In order to confirm the existence of these effects and to verify their possible correlation with the dopaminergic control system, further studies are necessary.

Immunotechniques for epidemiology of malaria: appropriate tools for integration of primary health care with malaria research and control

Community-based malaria control with integrated primary health care appears to be the most feasible approach for endemic countries in their struggle against malaria. To plan and implement personal protection and vector control measures, there is the need for comprehensive information about local modes of transmission. Experience with insecticide-based vector control programmes and entomological data accumulated over the years has revealed vector systems of extraordinary heterogeneity, creating multifaceted transmission situations. The primary health care-system offers an appropriate structure to collect and evaluate microepidemiological information countrywide. Community and health workers trained and supervised by qualified personnel could be involved in the assessment of clinical, parasitological and entomological indices. Community participation is facilitated if personnel are taught the use of immunotechniques. Tests can be performed on dried material which allows samples to be stored for months without refrigeration, so that transport to and processing in a central laboratory are not subject to time constraints. This paper describes and discusses enzyme-linked immunosorbent assays to determine if antibodies to sporozoites are present in blood collected as dried spots and to identify the origin of bloodmeals using dried mosquito abdomens.

Prevalence and levels of antibodies to the circumsporozoite protein of Plasmodium falciparum in an endemic area and their relationship to resistance against malaria infection

A study on malaria transmission, prevalence of infection and anti-sporozoite antibodies was carried out in Burkina Faso (West Africa). The prevalence and the levels of antibodies to (NANP)3 were found to be related to the entomological sporozoite inoculation rates measured at the same time in a defined area. The major inducer of anti-(NANP)3 antibody production under field conditions is sporozoite inoculation by infected mosquitoes. Levels of antibodies to (NANP)3 vary considerably with age and transmission season. High levels of anti-(NANP)3 antibodies raised under field conditions might offer protection against small inocula of sporozoites.

Detection and anatomical localization of Plasmodium falciparum circumsporozoite protein and sporozoites in the afrotropical malaria vector Anopheles gambiae s.l

Salivary glands from Anopheles gambiae s.l. collected in Burkina Faso, West Africa, were analyzed by both microscopic examination and immunoradiometric assay to determine the Plasmodium falciparum sporozoite rates. Using the same mosquito samples, the immunoassay revealed positive salivary glands with low sporozoite loads, which were frequently missed by microscopy. A closer agreement between both techniques was found using salivary glands with high sporozoite loads. We also found a number of mosquitoes with uninfected salivary glands which harbored the circumsporozoite antigen in their thoraces. In a particular village these mosquitoes represented 43.5% of all sporozoite antigen carrying specimens.

Immunity to Plasmodium sporozoites: recent advances and applications to field research

The presence of antibodies against Plasmodium falciparum sporozoites in humans living in malaria endemic areas was measured using as antigen the synthetic peptide (NANP)3, which represents the immunodominant region of the circumsporozoite (CS) protein. The results indicate that: i) the production of anti-CS antibodies is unrelated to the presence in the circulation of blood-stage parasites; ii) anti-CS antibodies, raised by natural inoculation, could exert a protective role against natural malaria infection; iii) anti-CS antibodies can be used as indicators of the intensity of malaria transmission.

CS antigen localization in malaria vectors: hypothetical refractoriness to transmission observed in the field

Indoor resting Anopheles gambiae s.l. were collected in two villages near Ouagadougou, Burkina Faso, and processed to investigate the presence and distribution of Plasmodium sporozoites. Salivary glands were dissected, examined by phase contrast microscopy and further processed by IRMA in order to reveal the presence of the circumsporozoite (CS) antigen of P. falciparum. The corresponding thoraces were homogenized and processed by IRMA. In the village characterized by the higher inoculation rate more than 40% of the infected mosquitoes were not found infective since CS antigen was detected in the thorax in absence of sporozoites and CS antigen in the corresponding salivary glands.

Field observations on the use of anti-sporozoite monoclonal antibodies for determination of infection rates in malaria vectors

Samples of indoor-resting Anopheles gambiae s.1. from Mali and Burkina Faso (West Africa) were processed in order to compare Plasmodium falciparum sporozoite rates obtained by immunoradiometric assay (IRMA) with circumsporozoite (CS) monoclonal antibody and by microscope examination of salivary glands. The immunological method provided sporozoite rates always higher than those obtained by microscope examination. This result does not appear to be related to cross-reactions involving non-sporozoite antigens. A small fraction of IRMA-positive mosquitoes is necessarily negative by microscope, since these mosquitoes actually contain the CS antigen only in the abdomen, presumably in connection with the presence of fully mature oocysts. However, the frequency of these mosquitoes cannot explain in itself an average ratio of 1:2 between microscope and IRMA sporozoite rates. A more important source of difference appears to depend on the detection of positive mosquitoes with low sporozoite numbers which remain more frequently undetected by microscope examination. Failure of salivary gland penetration by sporozoites is also considered as a possible source of discrepancy between the two methods.

A new method for identification of the animal origin of mosquito bloodmeals by the immunobinding of peroxidase-anti-peroxidase complexes on nitrocellulose

A method is described for identification of the animal origin of mosquito bloodmeals (MBM). The immunoassay is named DOT-PAP, it makes use of nitrocellulose as solid phase and of peroxidase-anti-peroxidase soluble complexes as detectors. DOT-PAP includes a built-in absorbing system to remove possible cross-reactivities. The sensitivity of the assay is higher than that of precipitin test or ELISA, and it dispenses with machineries for the reading of results. The method requires nanogram amounts of antigen, therefore it lends itself to the identification of incomplete MBM and of 28 h digested MBM as well. The assay can be applied to different hematophagous arthropods and the small volumes of antigen used allow to scan a vast array of possible animal sources on the same bloodmeal.

[Potential ratios among blood levels of various blood proteins in the cord blood of healthy newborn infants]

The authors have studied the correlations between IgA, IgG, IgM, C3c, C4, alpha 1-AGP and the total proteins, total globulins, alpha 1, alpha 2-globulins in normal newborn cord blood. The results indicate some significant correlations between C3c and C4, C3c, C4 and alpha 1-AGP, C3c, C4, alpha 1 1/2AGP and alpha 2-globulins, C4 and beta-globulins, C3c and alpha 1-AGP. The most significant finding has been inverse correlation between IgA and alpha 1, alpha 2-globulins, total globulins and total proteins.

n-Hexane metabolism in occupationally exposed workers

Lung uptake and excretion of n-hexane were studied in ten workers in a shoe factory. Simultaneous samples of inhaled and alveolar air were collected with the aid of a Rhan-Otis valve, personal samplers, and charcoal tubes. Alveolar excretion was monitored during a six hour postexposure period. Uptake was calculated from lung ventilation, the retention coefficient, and environmental concentrations. The amount of exhaled n-hexane was calculated from the decay curve. According to the experimental data, alveolar retention was about 25% of the inhaled n-hexane, corresponding to a lung uptake of about 17%. The postexposure alveolar excretion was about 10% of the total uptake. The main metabolites of n-hexane were identified and measured by capillary GC/MS in spot urine samples collected before, at the end, and 15 hours after the same working shift. Urinary concentrations were low, though related to n-hexane in the air. 2,5-Hexanedione in the end of shift samples gave the best estimate of overall exposure. About 3 mg/g creatinine of 2,5-hexanedione would correspond to about 50 ppm of n-hexane in the air (mean daily exposure).

[Effects of the use of FRIGEN (AG-Ffm-HOECST) on the determination of blood levels of some proteins (IgA, IgM, IgG, C3c, C4) in cord blood of healthy newborn infants at term by laser nephelometry]

The purpose of this paper is to establishes the FRIGEN effects on the determination of IgA, IgM, IgG, C3c, C4 cord-blood levels, by means of laser-nephelometry. The results show substantial interferences only in the IgA levels, whereas the other on almost all proteins are not affected, the found interference can be due to the amount of IgA bound to B-lipoprotein, that are precipitated by FRIGEN.

Computer programs in nucleic acid synthesis: synthetic strategy development using solid-phase chemical techniques with data storage, retrieval and analysis capabilities

A computer program has been designed to aid development of synthetic strategies for oligonucleotides produced by solid-phase chemical techniques. The program reduces the time required to develop a strategy and a data file from hours to minutes. The program contains inventories, provides cost analyses, and generates and stores other associated data. The program searches an inventory of sequences for that sequence to avoid duplicate synthesis. If the sequence is not in the inventory the program devises a synthetic strategy, calculates the amounts of reagents and labor costs necessary to complete the synthetic oligonucleotide. The program also deducts the reagents from inventory files. Physical data is also calculated. A file is generated in a sequence inventory for storage of the data as well as other data that will be generated during the purification processes. All variable parameters can be easily edited. The programs were designed to provide a cross-referencing feature for data analysis and can use several parameters as a constant.

Computer programs in nucleic acid synthesis: synthetic strategy development using solid-phase chemical techniques with data storage, retrieval and analysis capabilities

A computer program has been designed to aid development of synthetic strategies for oligonucleotides produced by solid-phase chemical techniques. The program reduces the time required to develop a strategy and a data file from hours to minutes. The program contains inventories, provides cost analyses, and generates and stores other associated data. The program searches an inventory of sequences for that sequence to avoid duplicate synthesis. If the sequence is not in the inventory the program devises a synthetic strategy, calculates the amounts of reagents and labor costs necessary to complete the synthetic oligonucleotide. The program also deducts the reagents from inventory files. Physical data is also calculated. A file is generated in a sequence inventory for storage of the data as well as other data that will be generated during the purification processes. All variable parameters can be easily edited. The programs were designed to provide a cross-referencing feature for data analysis and can use several parameters as a constant.

[Normal values of IgA, IgM, IgG, C3c, C4 and alpha 1-acid glycoprotein in blood from the umbilical cord of healthy newborn infants using laser-nephelometry. I: IgA, IgM]

The authors have determined, using the laser-nephelometric technique, the concentration of IgA and IgM in the umbilical cord blood of normal newborns. The results obtained are sufficiently in agreement with literature data, even if there are some differences derived by methods and environmental factors.

[Normal values of IgA, IgM, IgG, C3c, C4, alpha 1-acid glycoprotein in blood from the umbilical cord of healthy newborn infants using laser-nephelometry. II: IgG]

The authors have determined, using the laser-nephelometric technique, the concentration of IgG in the umbilical cord blood of normal newborns. The results obtained are sufficiently in agreement with literature data, even if there are some differences derived by methods and environmental factors.

[Normal values of IgA, IgM, IgG, C3c, C4, alpha 1-acid glycoprotein in blood from the umbilical cord of healthy newborn infants using laser-nephelometry. III: C3c, C4, alpha 1-acid glycoprotein]

The authors have determined, using the laser-nephelometric technique, the concentration of C3c, C4 and alpha 1-acid glycoprotein in the umbilical cord blood of normal newborns. The results obtained are sufficiently in agreement with literature data, even if there are some differences derived by methods and environmental factors.

Hemangiomas of the large bowel. Report of a case

This report concerns a 19-year-old man who complained of rectal bleeding of about one year's duration. Colonoscopy revealed a 10-cm segment of sigmoid colon characterized by the presence of multiple lesions identified as probable hemangiomas; one sessile dark tumor, 0.5 cm large, was snared endoscopically; histologic examination revealed a cavernous hemangioma. Three weeks later anterior resection was performed and histologic examination of the surgical specimen confirmed the diagnosis of hemangiomas.

Hemoimmuno-adherence test (HIAT) for the detection of antibodies anti-Toxocara canis L2 larvae

The use of a hemoimmuno-adherence test (HIAT) for detecting antibodies anti-L2 larvae of Toxocara canis is presented. The HIAT allows to reveal the presence of antibodies in the sera of both naturally and experimentally infected animals. The sensitivity of HIAT appears to be comparable to that of methods such as immunoenzymatic ones.