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Biomedical subjects

G Turner

Publications and source records attributed to G Turner.

At least 253 records · Page 14Linked to original sources
PubMed1979

Mitochondrial ATPase complex of Aspergillus nidulans and the dicyclohexylcarbodiimide-binding protein.

The dicyclohexylcarbodiimide-binding protein of Aspergillus nidulans has been identified as the smallest subunit of the mitochondrial ATPase complex, and has a molecular weight of approximately 8000. It is extractable from whole mitochondria and from the purified enzyme in neutral chloroform/methanol, contains 30% polar amino acids, and the N-terminal amino acid has been identified as tyrosine. Using a double-labelling technique in the absence and presence of cycloheximide, followed by immunoprecipitation of the enzyme complex with antiserum against Neuospora crassa F1 ATPase, it has been shown that this subunit is synthesized on cytoplasmic ribosomes.

Adenosine Triphosphatases↗
PubMed1979

Protein-to-wet weight relationships in supragingival plaques from caries-prone tooth surfaces.

The ratio of protein to wet weight in unpooled samples of supragingival plaques from sound and carious tooth surfaces was studied. Protein was assayed by a procedure developed for the study, in order to achieve a sensitivity of 1 microgram with minimum effects upon quantitation from protein composition and nonprotein components. Ratios of protein to wet weight in plaque specimens from caries-free surfaces were almost equally distributed into two main categories of 9.4% and 6.5%. Corresponding values for specimens from carious surfaces were 9.1% and 5.0%. The occurrence of high and of low values among samples from each type of surface indicated that the plaques differed quantitatively in protein, water, or a nonprotein component, possibly extracellular polysaccharide. Although compositional differences between plaques from the two types of surfaces were indicated by the lower ratios of 6.5% from noncarious and 5.0% from carious surfaces, they were not indicated by the higher ratio values, which were similar. These results suggest either that protein-to-wet weight ratios are not related to caries, or that the ratio values are related to caries for some but not all types of plaques.

Bacterial Proteins↗
PubMed1978

Six children affected by maternal alcoholism.

Six children affected by the fetal alcohol syndrome (FAS) are described. Their ages vary from newborn to 15 years. All had multigravid, alcoholic mothers. All have the facial features of the FAS, and prenatal and postnatal growth retardation. Four have additional congenital anomalies, and at least four are mentally retarded. These children are described to increase awareness of the FAS in Australia, whose population has a high and changing pattern of alcohol consumption.

Adolescent↗
PubMed1978

Compact liquid nitrogen storage system yielding high recoveries of gram-negative anaerobes.

A simple and compact system suitable for the preservation of fragile gram negative anaerobes and other bacteria in liquid N2 has been developed. Polypropylene straws used as specimen containers can be used easily within glove bags of anaerobic chambers, and their small size greatly increases the number of cultures which can be stored. Ancillary equipment and methods developed are described. The overall system was tested, using Streptococcus mutans, Fusobacterium nucleatum, and Selenomonas sputigena. Various basal suspending fluids and cryoprotective supplements were studied. With fast rates of freezing and thawing, survival recoveries of the test microorganisms ranged from 80 to 100 percent of the input colony-forming units in a complex medium broth base without cryoprotective agent addition, and they consistently were 100 percent when 0.4 mM polyvinylpyrrolidine was used. Overall, cryoprotection by polyvinyl pyrrolidine was superior to that from glycerol or dimethyl sulfoxide, the latter yielding recoveries similar to or less than those obtained with no cryoprotectant additive. All microorganisms were recoverable after storage for 1 year.

Dimethyl Sulfoxide↗
PubMed1978

Homocystinuria in New South Wales.

Homocystinuria was studied in 27 patients from 15 families in New South Wales. All 2 had biochemical findings consistent with cystathionine synthetase deficiency. One patient was ascertained by newborn screening, but the remaining index cases were detected because of symptoms: poor eyesight 6, mental retardation 3, thromboses 2, skeletal abnormalities 2, and urinary infection1. 9 patients, one-third of all cases, were mildly affected: either they had no features of the disease, or these did not occur until the late teens. Pyridoxine responsiveness was found in 8 sibships, and clinically there were two distinct kinds of response. For patients born in the decade 1960-69 the ascertainment rate for the total population was 1:58 000. The true incidence must be much higher. Our series indicates that homocystinuria occurs more frequently than has heretofore been thought, and that mild cases are common. It is likely that cases are often missed in current newborn screening programmes.

Adolescent↗
PubMed1978

Wet weights of dental plaques.

A method for weighing samples of plaque using a weighing assembly comprising a sample-bearing boat, held in a closed capsule to avoid moisture loss to room or balance environment is described. The system described is an objective device for measuring, by wet weight the amounts of plaque accumulating under various conditions of oral hygiene.

Bacteria↗
PubMed1978

Comparison studies on potency tests for rabies vaccines.

Eleven laboratories from eight countries and four continents took part in a collaborative study to evaluate experimental procedures to be used in selecting the new standard reference rabies vaccine prepared in human diploid cell cultures. The following procedures were used : (a) the NIH potency test in mice, (b) the antibody binding technique (by either mouse inoculation or the tissue culture method), (c) virus-neutralizing antibody levels in mice used for the NIH test, and (d) antibody induction in human volunteers treated with vaccine alone and in combination with human rabies gamma globulin. The four methods used for determination of rabies antibodies were mouse inoculation, rapid fluorescent focus inhibition, plaque reduction and complement fixation techniques. All results were expressed in International Units as compared to the standard WHO serum and vaccine preparations. In general, a close correlation was noted in results from different laboratories, and it was recommended that the future rabies standard vaccine should be evaluated by three testing procedures, the NIH test, the antibody-binding technique, and antibody levels in mice used for the NIH test.

Animals↗
PubMed1978

Studies on candidate reference preparations of rabies vaccine.

Two candidate reference rabies vaccines were tested in a collaborative study involving seven laboratories. Using four different testing procedures it was determined that both vaccine preparations were highly potent and demonstrated satisfactory stability in the thermal degradation test.

Animals↗
PubMed1978

Comparative study on antibody determination by different methods in sera of persons vaccinated with HDCS rabies vaccine.

The comparative studies undertaken by 7 laboratories in 6 countries show that the calculation of I.U.'s did not, as anticipated, minimize but actually enhanced the variability of results of rabies antibody estimations in the sera of HDCS vaccinees. The high biological variance in the method(s) may not have been considered by individual laboratories and any neglect of fundamental biostatistical laws unfortunately diminishes the theoretical advantage of using the "International Standard (I.S.)" as a "tertium comparationis". Perhaps the intrinsic variability of the I.S. should be re-evaluated and it is conceivable that a pure IgG fraction of rabies antiserum would show less variability. Intralaboratory variation might be reduced by agreeing that only a geometric mean of the I.S., and not a single value obtained in an individual test, should be used for calculation of I.U.'s. Application of the principles of biochemical and pharmacological methods, such as test-to-test control of the I.S. and its analytical variances might well enhance the reproducibility of the results. MNT, RFFIT, PRT and CFT were unable to detect antibodies in HDCS vaccinees until 7 days after the first vaccination. The establishment of methods for detecting early antibody requires further investigation.

Analysis of Variance↗
PubMed1978

Comparative study on antibody determination by different methods in sera of persons vaccinated with HDCS-vaccine.

The comparative studies undertaken by 7 laboratories in 6 countries show that the calculation I.U.s did not as anticipated minimize but actually enhanced the variability of results of Rabies antibody estaminations in the sera of HDCS vaccines. The high biological variance in the method(s) may not have been considered by individual laboratories and any neglect of fundamental biostatistical laws, unfortunately, diminishes the theoretical advantage of using the "International Standard (I.S.)" as a "tertium comparationis". Perhaps the intrinsic variability of the I.S. should be re-evaluated and it is conceivable that a pure IgG fraction of Rabies antiserum would show less variability. Intralaboratory variation might be reduced by agreeing that only a geometric mean of the I.S., and not a single value obtained in an individual test, should be used for calculation of I.U.s. Application of the principles of biochemical and pharmacological methods, such as test-to-test control of the I.S. and its analytical variances might well enhance the reproducibility of the results. MNT, RFFIT, PRT and CFT were unable to detect antibodies in HDCS vaccinees until 7 days after the first vaccination. The establishment of methods for detecting early antibody requires further investigation.

Antibodies, Viral↗
PubMed1977

Extranuclear recombination in Aspergillus nidulans: closely-linked multiple chloramphenicol- and oligomycin-resistance loci.

A nuclear, chloramphenicol-sensitive mutant cas-1 has been isolated which is cross sensitive to a number of drugs, including oligomycin and cycloheximide. Approximately one-third of the chloramphenicol-resistant mutants isolated from mutagenized conidia of this strain were found to be extranuclear, and exhibited a variety of phenotypes. One of these mutants, designated (camB51), was slow growing on drug-free medium and recombined at low frequency with the previously described mutant (camA112) (Gunatilleke et al., 1975). The majority of extranuclear oligomycin-resistant mutants isolated from cas-1 were indistinguishable from (oliA1) (Rowlands and Turner, 1973). Two mutants, (oliB322) and (oliB332), with similar but not identical phenotypes to (oli A1), recombined with the latter at low frequency but not with each other, thus representing a new class of extranuclear mutants.

Aspergillus nidulans↗