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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 343 records · Page 19Linked to original sources
PubMed1987

The use of specific DNA probes to analyse the Sxr mutation in the mouse.

The mouse Y chromosome plays a fundamental role in the control of primary sex determination and fertility. Both genetic and molecular biological evidence has shown that much of the necessary information is contained in a minute piece of the Y (the Sxr region) which has arisen by a duplication of the pericentric region of the normal Y and the transposition of one copy to the distal pseudoautosomal region. The present article describes the isolation of random Y-chromosome probes and their use to investigate this Sxr region at the molecular level. Total mouse Y-chromosome libraries were constructed from flow-sorted material and a Sxr regional library after specific microdissection and cloning. Transcription has been detected in the testis using both Sxr-specific and non Sxr-located genomic probes taken from these libraries. In addition, we have been able to confirm the presence of an active steroid sulphatase gene on the mouse Y. This gene is located in the distal portion of the pseudoautosomal region and is tightly linked to Sxr. Finally, using an Sxr-specific probe we can define multiple Y-chromosome haplotypes in the mouse showing that the region is evolving very rapidly.

Animals↗
PubMed1986

Sequence analysis and transformation by the catabolic 3-dehydroquinase (QUTE) gene from Aspergillus nidulans.

The induction of catabolic 3-dehydroquinase by quinic acid in Aspergillus nidulans has been shown to involve transcriptional control and yields a single major 0.8 kb mRNA. The nucleotide sequence of the catabolic 3-dehydroquinase QUTE gene has been determined and contains a single uninterrupted open reading frame of 462 bases encoding a 16,505 Da protein of 153 residues. Comparison with the corresponding QA2 gene of Neurospora crassa reveals the absence of 75 nucleotides encoding 25 amino acids from the centre of the QUTE gene of A. nidulans and the presence of 21 additional nucleotides at its 3' end. There is no nucleotide or amino acid homology between these two elements. A 16 bp inverted repeat (5' GGCAGAGCGTTCTGCC) shows similarity to such repeats found in other fungal promoters. The functional integrity of the QUTE gene was demonstrated by the transformation of a qutE mutant strain which regains growth on quinic acid as sole carbon source. Four of the twelve transformed strains examined contained vector sequences integrated at the qutE locus, and these strains all exhibited normal regulation of 3-dehydroquinase even when 16 copies of the QUTE gene were present.

Amino Acid Sequence↗
PubMed1986

Needle catheter duodenostomy: a technique for duodenal alimentation of birds.

A technique for duodenal alimentation (needle catheter duodenostomy) of birds was developed, using the domestic pigeon (Columba livia) as the experimental model. A needle catheter was inserted into the descending duodenum of 5 pigeons and was secured to the body wall and dorsum of each bird. A liquid diet was administered daily (in equal amounts of 0, 4, 8, 12, and 16 hours) for 14 days without adverse effects. On day 15, the catheters were removed, and the birds immediately resumed normal consumption of a pigeon ration and water diet. Although 4 of the 5 birds had minor weight loss, dietary alterations probably could be used on an individual basis to alleviate this problem. After oral alimentation was resumed, the 5 birds exceeded their initial body weight within 7 days. Four weeks after catheter removal, positive-contrast radiographic evaluations indicated that the duodenum of each pigeon appeared normal. Needle catheter duodenostomy was a viable method of alimentation in the domestic pigeon. This technique should be applicable for other avian species requiring bypass of the upper gastrointestinal tract proximal to the region of catheter insertion in the duodenum.

Animals↗
PubMed1986

The development of a microcomputer system for poisons information retrieval.

The Poisons Information Centre at the Red Cross War Memorial Children's Hospital in Cape Town makes use of a microcomputer for information retrieval. An outline is given of the data base design and the manner in which data were collected and collated. User operation of the system is described and its effect on the efficiency of the service noted.

Data Collection↗
PubMed1986

Herpes simplex virus detection by ELISA: effect of enzyme amplification, nature of lesion sampled and specimen treatment.

The relative sensitivity of two enzyme detection procedures was investigated in a simultaneous "monoclonal" ELISA for herpes simplex virus (HSV). A cyclical enzyme amplified detection system with alkaline phosphatase, rather than horse-radish peroxidase and a conventional chromogenic substrate, gave an increase in absolute sensitivity and a 20 to 30% increase in the detection of HSV in routine isolation-positive genital specimens collected in transport medium. The HSV detection rate, with both procedures, was shown to vary with the site and clinical stage of lesion sampled; it was highest with penile vesicular lesions. Direct extraction of the swab specimen in a small volume of diluent further increased the sensitivity of antigen detection giving positive and negative predictive values of 100 and 96% respectively. The overall sensitivity of HSV detection was equivalent to that obtained by isolation in cell culture. The amplified ELISA offers an alternative, rapid, simple, non-culture technique for routine HSV diagnosis that does not rely upon retention of virus viability.

Alkaline Phosphatase↗
PubMed1986

Cloning of DNA libraries from mouse Y chromosomes purified by flow cytometry.

To purify mouse Y chromosomes by flow cytometry, a male cell line containing the Robertsonian translocation Rb(9.19)163H has been established by SV40 transformation. Flow karyotypes obtained from these cells exhibit a well-isolated peak of fluorescence corresponding to the single Y chromosome, clearly distinct from that of chromosome 19. From this peak, 650,000 chromosomes were sorted, and two restriction fragment libraries were constructed from the DNA of the sorted chromosomes. The characterization of several Y-specific fragments has shown that the Y DNA was enriched at least 36-fold. Furthermore, given that there are likely homologies between the X and Y chromosomes, we can assume that this calculated value of the purification factor is an underestimation and that the Y DNA was more highly purified by flow sorting.

Animals↗
PubMed1986

Arthrographically assisted splint therapy: a 6-month follow-up.

After repositioning splint therapy, 51 patients were evaluated for a minimum of 6 months. Forty-five (88%) of the patients were considered to have been treated successfully, whereas six (12%) patients required surgery to correct meniscal displacement. A detailed analysis of signs and symptoms before and after splint treatment is in progress.

Adolescent↗