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Biomedical subjects

J F Aitken

Publications and source records attributed to J F Aitken.

27 records · Page 2Linked to original sources
PubMed1990

The gene encoding the phosphatidylinositol transfer protein is essential for cell growth.

Phosphatidylinositol transfer proteins (PI-TPs) catalyze the transfer of phosphatidylinositol and phosphatidylcholine between membranes in vitro. However, the in vivo function of these proteins is unknown. In this paper, we use a combined biochemical and genetic approach to determine the importance of PI-TP in vivo. An oligonucleotide based on the amino-terminal sequence of the PI-TP from Saccharomyces cerevisiae was used to screen a yeast genomic library for the gene encoding PI-TP (PIT1 gene). Positive clones showed overproduction of transfer activities and transfer protein in the 100,000 x g supernatants. The 5' terminus of the PIT1 gene correlates with the predicted codons for residues 3-30 of the determined protein sequence. A putative intron is located between the codons for residues 2 and 3 of the protein sequence. The codons for the first two amino acids of the protein and the presumptive initiation methionine precede the intron. Tetrad analysis of a heterozygous diploid (PIT1/pit1::LEU2) revealed that the PIT1 gene is essential for cell growth. Nonviable spores could be rescued by transformation of the above diploid prior to sporulation, with a plasmid-borne copy of the wild type gene.

Amino Acid Sequence↗
PubMed1984

Antisera to synthetic peptide recognize high molecular weight enkephalin-containing proteins.

Antisera to a synthetic peptide corresponding to the 95-117 sequence of proenkephalin were used to develop a sensitive radioimmunoassay. Gel-filtration of acid extracts of bovine adrenal medulla and purified chromaffin granules revealed that the antisera recognized high molecular weight material (Mr approximately 5,000-30,000). The material in peak I ( Mr 20 ,000-30,000) and peak II (Mr 10,000-20,000) was further purified by immunoaffinity chromatography. Sequential digestion of each of these fractions with trypsin and carboxypeptidase B generated immunoreactive Met-enkephalin. This study demonstrates that antisera against a synthetic peptide cross-react with high molecular weight enkephalin-containing precursors, validating the use of these antisera in studies of enkephalin biosynthesis.

Adrenal Medulla↗
PubMed1984

Dental status of pregnant women attending a Brisbane maternity hospital.

A sample of 314 consecutive women attending for their first antenatal visit at a public hospital were examined according to the WHO survey procedure. The women's age ranged from 16 to 42 yr with a mean of 23.5 yr. Only 3% were edentulous in both jaws, but 13% had some form of denture. A quarter had pocketing in at least one sextant and only 16% were free of gingivitis. The average number of DMF teeth was 15.8, comprising 2.7 decayed, 4.5 missing and 8.6 filled teeth; 70% had teeth needing restoration and 10% had at least one tooth needing extraction. There were significant relationships between DMF score and age (positive) and between number of teeth needing restoration and age, educational level, and the woman's own perception of her dental health (all inverse). Some form of dental attention was needed by 86% of the women; 12% had conditions needing immediate attention. By comparison with a 1971 study of pregnant women in Brisbane, there has been a marked decline in DMFT score (from 19.1 to 15.8).

Adolescent↗
PubMed1983

A radiographic study of chronic periodontitis in 15 year old Queensland children.

A retrospective study was carried out to determine the frequency of early periodontal bone loss in 15 year olds as seen in bite-wing radiographs. A total of 468 radiographs of 15 year olds was examined, 246 from 1970-74 and 222 from 1978-80. The alveolar bone crest on the mesial and distal of the first permanent molar teeth was examined for radiographic evidence of early chronic periodontitis. The condition of the adjacent proximal tooth surfaces was also recorded. No significant difference was found between the two groups; 39% of the 1978-80 and 43% of the 1970-74 group showed radiographic evidence of early chronic periodontitis (P less than 0.05). Males and females showed a similar frequency of periodontal disease levels. The mesial interproximal space of the first molars had significantly higher frequencies of radiographic evidence of chronic periodontitis than the distal interproximal spaces in the two groups examined. Fewer proximal restorations with overhangs were noted in the 1978-80 group, however more proximal subgingival calculus was found in this group than the 1970-74 group.

Adolescent↗
PubMed1983

Experimental gingivitis in humans. A clinical and histologic investigation.

AN EXPERIMENTAL GINGIVITIS STUDY was carried out to relate the clinical parameters (plaque and gingival index) to the histologic appearance of the associated gingival lesions. Fifteen third-year dental students took part in the study. Following the withdrawal of oral hygiene, biopsies were taken on days 0, 4, 8 and 21 of the experimental period. A statistically significant association was found between the plaque and gingival indices and the various time intervals throughout the experimental period (P less than 0.001). At day 0, although all sites had a GI of 0, all but 2 of the 15 specimens showed some degree of inflammation. Histologically, these lesions consisted of over 60% lymphocytes, while plasma cells comprised less than 5% of the infiltrating population. Although the degree of inflammation increased both clinically and histologically throughout the experimental period, the nature of the infiltrate did not change significantly. Lymphocytes remained as the dominant cell type. In fact, no association was seen between the degree of inflammation and the nature of the infiltrating cells.

Dental Plaque Index↗