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Biomedical subjects

J F de Castro

Publications and source records attributed to J F de Castro.

11 recordsLinked to original sources
PubMed2000

Response to different measles vaccine strains given by aerosol and subcutaneous routes to schoolchildren: a randomised trial.

BACKGROUND: More than one dose of measles vaccine is necessary for the sustained control of measles. The aerosol route is thought to be more immunogenic for booster doses than traditional subcutaneous injections, so we did a randomised comparative trial of aerosol and subcutaneous measles vaccines in South African schoolchildren. METHODS: 4327 schoolchildren (aged 5-14 years), assigned by block randomisation of classrooms, received standard titre doses of either Schwarz or Edmonston-Zagreb measles vaccines subcutaneously or by aerosol. Blood samples for antibody assay were collected before vaccination, at 1 month, and 1 year after vaccination. The main endpoints (antibody titres at 1 month and 1 year) were compared between groups. FINDINGS: 992 children had antibody titre data available for all timepoints. 14 (3.6%) of 385 children who received Edmonston-Zagreb vaccine by aerosol were seronegative 1 year after vaccination, compared with 28 (8.6%) of 326 children who received Edmonston-Zagreb subcutaneous vaccine and 39 (13.9%) of 281 children who received Schwarz subcutaneous vaccine. At 1 month, 326 (84.7%) children who received aerosol Edmonston-Zagreb vaccine had seroconverted, compared with 257 (78.8%) who received subcutaneous Edmonston-Zagreb vaccine and 176 (62.6%) who received subcutaneous Schwarz vaccine. At 1 month, only 116 (22.7%) of 511 children in the Schwarz aerosol group had seroconverted; this aerosol vaccine had no detectable potency after 2 min of nebulisation. There were no serious side-effects: about 5% of children in each group had a rash within 2 weeks of vaccination. INTERPRETATION: An aerosol vaccination method that uses currently available devices and a suitably stable vaccine is effective and acceptable. This form of delivery is adaptable to mass campaigns, avoids the risks associated with injections, and could help measles eradication.

Administration, Inhalation↗
PubMed1997

Using Novafil: would it make suturing easier?

The use of monofilament nonabsorbable suture materials is not common in Dentistry. Although it is known that multifilament suture materials induce greater cellular reaction, most Dentists prefer to use cotton and silk. Rigidity and package memory are disadvantages of monofilament nonabsorbable suture materials. A new material, Polybutester (Novafil), has been used successfully in Medicine but its use is not common in Dentistry. Seventy male and female Wistar rats were used to study the clinical response of skin and abdominal wall muscle to the use of Novafil and nylon sutures. Under general anesthesia, standard wounds were created in the dorsum and abdomen of the animals and sutured with either Novafil or nylon. The animals were sacrificed immediately, 12, 24, and 72 hours and at 4, 5 and 7 days to evaluate the clinical aspect of both wounds. Polybutester presented some advantages such as strength, lack of package memory, elasticity and flexibility which made suturing quicker and easier. Some subjects presented abdominal wound edema during the period and six animals developed infection of abdominal wounds within seven days. These initial findings show that Novafil is easy to handle and would be better tolerated in the mouth than nylon resulting in less discomfort for the patient. Novafil can be used safely on skin and mucosal wounds and, if necessary, it can be used in internal sutures because it irritates less than nylon.

Abdominal Muscles↗
PubMed1984

Poly(A)+ RNA metabolism during change of physiological state of Tetrahymena pyriformis cells.

In the present work the metabolism of poly(A)+ RNA was investigated in cells of Tetrahymena pyriformis derived either from stationary cultures or from starved suspensions that were initiating growth. Under these circumstances the organisms derived from stationary cultures synthesize ribosomal and poly(A)+ RNA and form polysomes. In the presence of actinomycin D (actD) the observed expansion of the polysomal population is arrested. Pre-starved cells, on the other hand, start making polysomes in the virtual absence of ribosomal and poly(A)+ RNA synthesis soon after being transferred to peptone medium. In this case polysome formation is only partially sensitive to actD. These results have been interpreted as indicating that, in the beginning of growth, cells derived from stationary cultures are dependent on RNA synthesis for polysome formation, whereas pre-starved cells use pre-synthesized RNA for the same purpose.

Animals↗
PubMed1975

Nalidixic acid and macromolecular metabolism in Tetrahymena pyriformis: effects on protein synthesis.

A study on the effect of nalidixic acid on macromolecular metabolism, particularly of protein, in Tetrahymena pyriformis was performed. It was shown that the compound is a potent inhibitor of deoxyribonucleic acid, ribonucleic acid, and protein synthesis for this organism. A conspicuous breakdown of polysomes, accompanied by the accumulation of 80S ribosomes, occurred in cells incubated for 10 min with the drug; polysome formation was prevented. The accumulating 80S particles were shown to be run-off ribosomal units. The incorporation of amino acids by a cell-free system is not affected by nalidixic acid. In nonproliferating cells the incorporation was also not prevented, unless the cells were previously incubated with the drug. These results are discussed in terms of the possible mechanism of action of nalidixic acid in T. pyriformis.

Animals↗