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Biomedical subjects

G Saunders

Publications and source records attributed to G Saunders.

At least 37 records · Page 2Linked to original sources
PubMed1992

Mitotic instability of integrated plasmids in Penicillium chrysogenum transformants.

Transformation vectors based on the Streptoalloteichus hindustanus phleomycin-resistance gene placed under the control of either the Penicillium chrysogenum trpC or pcbC promoters were constructed (plasmids pGS1 and pGS7 respectively). Up to 100 transformants per microgram of DNA were obtained with pGS7 in P. chrysogenum strain P2. In order to follow the expression of additional penicillin biosynthetic genes introduced by transformation, a pcbC::lacZ gene fusion was introduced into pGS1, generating pGS6. Southern analysis of three pGS6 transformants indicated that the plasmid was integrated in tandem arrays. Revertants which had lost the exogenous beta-galactosidase activity, were detected for each transformant after several cycles of subculture on non-selective medium. Southern analysis indicated that the different phenotypes obtained resulted from the loss of part or all of the integrated plasmid copies.

Blotting, Southern↗
PubMed1991

Cloning and selective overexpression of an alkaline protease-encoding gene from Aspergillus oryzae.

The gene alpA encoding Aspergillus oryzae alkaline protease (ALP) was isolated from a genomic library of an industrial strain used in Thailand by using oligodeoxyribonucleotide probes based on the published cDNA sequence [Tatsumi et al., Agric. Biol. Chem. 52 (1988) 1887-1888]. The entire nucleotide sequence of the genomic clone obtained was determined. By comparison with the published cDNA sequence, it was found that ALP is encoded by four exons of 314, 445, 89 and 351 bp. Three introns, which interrupt the coding sequence, are 50, 59 and 56 bp in length. The gene contains a typical TATA box 103 bp upstream from the start codon, and a consensus polyadenylation signal, AATAAA, 189 bp from the stop codon. The alpA gene, introduced into a protease deficient strain (A. oryzae U1638) by cotransformation, directed the secretion of enzymatically active ALP into the culture medium. Cotransformants of the high-level ALP-producing strain U212 containing multiple copies of the alpA gene were able to secrete up to five times more ALP than the parental strain.

Amino Acid Sequence↗
PubMed1991

Direct pulsed field gel electrophoresis of Wilms' tumors shows that DNA deletions in 11p13 are rare.

In order to search for small tumor-specific deletions in 11p13 we analysed DNA isolated from 30 fresh Wilms' tumor (WT) samples with pulsed field gel electrophoresis. For these studies we have isolated new probes from the ends of several Notl fragments. Using these and previously described probes from 11p13 we first completed and extended the existing map of the 11p13 region. The analysis of the tumor material showed that (I) tumor-specific deletions were very rare: one homozygous deletion out of 30 tumors analysed, (2) hemizygous deletions were not observed in any of the tumors. The homozygous deletion in one patient spans 220 kb and is composed of a tumor-specific translocation associated with a deletion on one chromosome and a deletion of about 220 kb on the other chromosome at the same site. The WT-33 Wilms' tumor candidate gene maps to this deleted segment. A small constitutional deletion of 1,300 kb was identified in a patient with WT and genital tract malformations. These results suggest that in the majority of sporadic WT loss of gene function is due to subtle alterations in the gene, e.g., point mutations or very small deletions.

Alleles↗
PubMed1991

The distal region of 11p13 and associated genetic diseases.

The distal region of human chromosome band 11p13 is believed to contain a cluster of genes involved in the development of the eye, kidney, urogenital tract, and possibly the nervous system. Genetic abnormalities of this region can lead to Wilms tumor, aniridia, urogenital abnormalities, and mental retardation (WAGR syndrome). Using 11 DNA markers covering the entire distal region of 11p13, including the WAGR region, we have carried out molecular studies on 58 patients with one or more features of this syndrome and patients with other diseases or structural cytogenetic abnormalities associated with 11p13. Cytogenetic analyses were performed in all cases. In 12 patients we were able to demonstrate deletions of this region. In 2 patients balanced translocations and in 2 additional patients duplications of this region were characterized. In total, 5 chromosomal breakpoints within 11p13 were identified. One of these breakpoints maps within the smallest region of overlap of WAGR deletions. Moreover, we were unable to demonstrate constitutional deletions in a candidate sequence for the Wilms tumor gene or any other marker in 2 patients with aniridia and urogenital abnormalities, 4 patients with Wilms tumor and urogenital abnormalities, 5 patients with bilateral Wilms tumors, and 3 familial Wilms tumor cases. We suggest that the molecular techniques used here (heterozygosity testing for polymorphic markers mapping between AN2 and WT1 and deletion analysis by dosage, cytogenetic analysis, or in situ hybridization) can be employed to identify sporadic aniridia patients with and without increased tumor risk.

Adolescent↗
PubMed1991

A standardized technique for lower limb radiography. Practice, applications, and error analysis.

The normal standing radiograph, which provides a view of the knee only, is prone to errors of parallax and poor control of patient positioning. A standardized radiographic procedure was developed to control these sources of error. Anteroposterior and lateral views of the lower limb (hip and knee) are obtained without moving the patient from a standardized position; this includes control of ankle position and limb rotation. To correct for parallax error, radiopaque markers are positioned between the patient and the x-ray source. The locations of bone landmarks and reference markers on the radiographs are digitized, and a software package provides a display of key parameters. Error analysis of the method confirmed that most angles were sensitive to contrived positional variations, especially limb rotation and knee flexion. Load distribution between limbs was not critical. The greatest error was random. Most angles were reproducible within +/- 1.3 degrees or less at 95% confidence.

Aged↗
PubMed1991

Predicted structure of the bovine calcitonin gene-related peptide and the carboxy-terminal flanking peptide of bovine calcitonin precursor.

We have isolated from a bovine genomic library a clone which contains the calcitonin (CT) and CT gene-related peptide (CGRP) sequences, using probes representing the human CT and CGRP sequences. Sequence analysis has identified the nucleotide sequence coding for bovine CT, its C-terminal flanking peptide and bovine CGRP. The deduced amino acid sequence of bovine CGRP revealed a significant homology with other CGRPs so far reported. It differs by only one amino acid from rat CGRP alpha and porcine CGRP, and by three and four amino acids from human CGRP beta and alpha respectively. Bovine CT has, however, only 14 out of 32 residues in common with human CT. As in the human CT precursor, the C-terminal flanking peptide of bovine CT precursor is a 21 amino acid peptide. It shares only 11 residues in common with its human counterpart. This study thus provides further evidence that CGRP, in contrast to CT and its C-terminal flanking peptide, is a highly conserved molecule.

Amino Acid Sequence↗
PubMed1991

Comparison of needle aspiration cytologic diagnosis with excisional biopsy tissue diagnosis of palpable tumors of the breast in a community hospital.

Fine needle aspiration cytologic examination has not extensively been used in our hospital in the work-up evaluation of solid tumors of the breast and its reliability as a basis on which to perform definitive treatment of carcinoma of the breast was in question. One hundred and five aspiration cytologic specimens were obtained from palpable solid tumors of the breast just prior to excisional biopsy. Specimens were numbered and submitted to three different staff pathologists for diagnosis in a single blind manner. Results were then compared with tissue diagnosis of the same tumors. Of 105 specimens taken at biopsy of the breast, 28 malignant lesions were diagnosed on the final tissue report. Of those, ten were diagnosed as malignant (Class V), two were highly suspicious (Class IV) and six were insufficient specimens (Class O). Of those diagnosed as class IV and V by the results of cytologic examination, all were malignant on permanent section for a specificity of 100 per cent and a sensitivity of 36 per cent. The cytologic diagnoses of Classes I, II and III did not correlate with any histologic report, benign or malignant. Malignant growths were misdiagnosed by cytologic examination in 36 per cent and missed because of inadequate specimens in 28 per cent. We believe that a Class V cytologic finding is sufficient basis on which to perform definitive treatment of carcinoma of the breast provided rigid criteria are used. There is a learning curve associated with this diagnostic modality.

Biopsy↗
PubMed1990

The genetic stability of Penicillium chrysogenum transformants in a fermentor.

A number of transformants of Penicillium chrysogenum have been obtained with the plasmid vector p3SR2. Southern analysis showed that transformation had occurred by integration of vector sequences into the nuclear DNA of the fungus. A number of transformants were tested for stability of the transformed phenotype in agar medium and some were found to be unstable. Two transformants, shown to be stable in agar culture, were grown in 5-1 batch fermentors for further stability tests. Over periods of up to 312 h in the fermentor both transformants were 100% stable with respect to the transformed phenotype. In addition Southern analysis of DNA extracted from the spent mycelium showed that no change had occurred in the position of the integrated vector sequences within the transformant nuclear DNA.

Blotting, Southern↗
PubMed1990

Constitutional and somatic deletions of two different regions of maternal chromosome 11 in Wilms tumor.

Loss of heterozygosity for 11p markers and preferential loss of maternal alleles have been described in Wilms tumor. In this report we describe the molecular characterization of the constitutional and somatic 11p rearrangements in a del(11p13) WAGR patient with Wilms tumor. Both rearrangements led to loss of maternal alleles for two different regions of 11p, namely, 11p13 and 11p14----p15. This result clearly suggests that Knudson's hypothesis of two hits at the same locus does not necessarily apply to Wilms tumor. Moreover, the loss of 11p15 maternal alleles in the tumor is not incompatible with maternal inheritance of predisposition at 11p13. The putative roles of these two loci are discussed.

Alleles↗
PubMed1990

Molecular analysis of the Azotobacter vinelandii glnA gene encoding glutamine synthetase.

The gene encoding glutamine synthetase (GS), glnA, was cloned from Azotobacter vinelandii on a 6-kb EcoRI fragment that also carries the ntrBC genes. The DNA sequence of 1,952 bp including the GS-coding region was determined. An open reading frame of 467 amino acids indicated a gene product of Mr 51,747. Transcription of glnA occurred from a C residue located 32 bases upstream of an ATG considered to be the initiator codon because (i) it had a nearby potential ribosome-binding site and (ii) an open reading frame translated from this site indicated good N-terminal homology to 10 other procaryotic GSs. Sequences similar to the consensus RNA polymerase recognition sites at -10 and -35 were present at the appropriate distance upstream of the transcription initiation site. As expected from earlier genetic studies indicating that expression of A. vinelandii glnA did not depend on the rpoN (ntrA; sigma 54) gene product, no sigma 54 recognition sequences were present, nor was there significant regulation of glnA expression by fixed nitrogen. Repeated attempts to construct glutamine auxotrophs by recombination of glnA insertion mutations were unsuccessful, Although the mutated DNA could be found by hybridization experiments in drug-resistant A. vinelandii transformants, the wild-type glnA region was always present. These results suggest that glnA mutations are lethal in A. vinelandii. In [14C]glutamine uptake experiments, very little glutamine was incorporated into cells, suggesting that glutamine auxotrophs are nonviable because they cannot be supplied with sufficient glutamine to support growth.

Amino Acid Sequence↗
PubMed1990

Clinical and laboratory evaluation of patients exposed to neurotoxicants.

For clinicians, toxicologists, and behavioral scientists, the steady contamination of the environment poses dynamic challenges for accurate diagnosis and evaluation of toxic exposure. The purpose of the neurotoxic evaluation is to determine the level of damage a toxic substance has caused to the biochemistry, physiology, and morphology of the central, peripheral, and autonomic nervous systems. A complete clinical neurotoxicologic assessment hinges on a thorough medical and occupational history, physical examination findings, and specific neurologic and neuropsychologic tests as well as laboratory evaluation.

Behavior↗
PubMed1989

Transformation of Penicillium chrysogenum with selection for increased resistance to benomyl.

Incubation of protoplasts of Penicillium chrysogenum with the plasmid pBT-3 permitted selection of transformants on the basis of increased resistance to the anti-fungal agent benomyl. Transformants were obtained at a frequency of 1-2 per microgram of DNA. Southern analysis revealed that transformation had occurred by integration of vector sequences into the host genome.

Benomyl↗
PubMed1989

Arteriosclerosis in a rabbit.

Extensive mineralization of the aorta, brachiocephalic trunk, and the left subclavian, both iliac, common carotid, and renal arteries were found at necropsy in a 3-year-old French Lop rabbit. The rabbit had been examined previously for seizures, at which time abdominal radiography revealed calcification of the abdominal aorta and external iliac arteries. Treatment was not initiated, and the rabbit died 4 months later of bacterial pneumonia. The rabbit also had hypercalcemia. In contrast to many species, the blood calcium concentrations of rabbits reflect dietary intake.

Animals↗
PubMed1989

Expression of the trpC gene from Penicillium chrysogenum in Aspergillus nidulans.

The heterologous expression in Aspergillus nidulans of a gene involved in tryptophan biosynthesis from Penicillium chrysogenum is described. With the chimeric plasmid pPC-31, which carries the cloned trpC gene, approximately 10-40 "stable" transformants per microgram of DNA were obtained, with selection for complementation of the mutant allele. This frequency was increased 10-fold by the insertion of the ans1 fragment into the transformation vector. Southern hybridization analysis revealed that transformation occurred as a consequence of the integration of vector sequences into the host chromosome at a variety of sites within the genome.

Aspergillus nidulans↗
PubMed1988

Using DRGs and standard costs to control nursing labor costs.

Nursing care is a very significant part of a healthcare organization's costs. However, until recently, methods of controlling nursing costs were largely ineffective. With the implementation of the prospective payment system and the use of diagnosis related groups, budgeting and controlling nursing costs are now possible with the use of standard costing. In this article, methods and procedures are discussed and explained for controlling inpatient nursing costs with the use of DRGs and standard costs.

Accounting↗
PubMed1986

Isolation of mutants sensitive to 2-aminopurine and alkylating agents and evidence for the role of DNA methylation in Penicillium chrysogenum.

Using high performance liquid chromatography, the presence of N6-methyladenine has been found at a level of 0.1 mol percent in DNA extracted from Penicillium chrysogenum. No 5-methylcytosine was detected. A mutant strain HP547, which is sensitive to the lethal effects of N-methyl-N'-nitro-N-nitrosoguanidine, methylmethane sulphonate and the base analogue 2-aminopurine shows an increased spontaneous mutation rate and no detectable DNA methylation. Comparison of restriction enzyme digests of wild type and undermethylated strains indicated that methylation was occurring at a different sequence to that of the Dam methylase system of E. coli.

2-Aminopurine↗
PubMed1986

The development of a surface arthroplasty for the elbow.

Complex kinematics, anatomical features, and load distribution have contributed to the poor function of constrained and semiconstrained cemented arthroplasties of the elbow. Resurfacing by porous-coated components has the potential, by reproduction of normal joint geometry and restoration of ligament balance, to re-create relatively normal kinematics and load-bearing and provide relief of pain. A method was developed to provide information on the geometry of the lower humeral joint surface and olecranon fossa. The information gained was used to design components to resurface the trochlea, capitellum, and olecranon fossa. A technique was also developed to remove a minimal amount of subchondral bone from the ulna and humerus in a precisely directed fashion for exact fit of the porous-coated components.

Elbow Joint↗