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Biomedical subjects

D Chisholm

Publications and source records attributed to D Chisholm.

18 recordsLinked to original sources

Two outbreaks of Salmonella enteritidis phage type 4 infection associated with the consumption of fresh shell-egg products.

In 1988 there were two outbreaks of infection with Salmonella enteritidis phage type 4 in adjacent local authorities. The first affected 18 of 75 helpers and guests who attended a private function. Investigations revealed that home-made vanilla ice-cream containing uncooked eggs was the vehicle of infection and the causative organism was identified at the premises of the egg producer. The second affected 84 of 422 delegates attending a conference dinner, and 12 of 50 hotel staff at risk. A dessert made with lightly-cooked egg yolk and raw egg white was associated with infection, and the epidemic strain was cultured from the shell of an egg and an environmental sample from the producer's farm. It is of interest that one outbreak involved free-range and one battery-produced eggs, and that in one the vehicle was prepared at home and in the other in commercial premises. In neither incident was any deficiency in standards of egg production or catering practice discovered.

Animals

Recovery of a soybean urease genomic clone by sequential library screening with two synthetic oligodeoxynucleotides.

We report the first isolation of a low-copy-number gene from a complex higher plant (soybean) genome by direct screening with synthetic oligodeoxynucleotide (oligo) probes. A synthetic, mixed, 21-nucleotide (nt) oligo (21-1) based on a seven amino acid (aa) sequence from soybean seed urease, was used to screen genomic libraries of soybean (Glycine max [L.] Merr.) in the lambda Charon 4 vector. Twenty homologous clones were recovered from a screen of 500,000 plaques. These were counterscreened with embryo-specific cDNA (15-2 cDNA) made by priming with a second, mixed 15-nt oligo (15-2), based on a Jack bean (Canavalia ensiformis) urease peptide [Takishima et al., J. Natl. Def. Med. Coll. 5 (1980) 19-23]. Five out of 20 clones were homologous to 15-2 cDNA and proved to be identical. Nucleotide sequence analysis of representative clone E15 confirmed that it contained urease sequences. Subclones of E15 homologous to the oligo probes contain a deduced amino acid sequence which matches 108 of 130 aa residues of an amino acid run in a recently published [Mamiya et al., Proc. Jap. Acad. 61B (1985) 359-398] complete protein sequence for Jack-bean seed urease. Using clone E15 as a probe of soybean embryonic mRNA revealed a homologous 3.8-kb species that is the size of the urease messenger. This species is absent from mRNA of embryos of a soybean seed urease-null mutant. However, both urease-positive and urease-null genomes contain the 11-kb DNA fragment bearing urease sequences.

Amino Acid Sequence

Isolation of multiple genomic sequences coding for chicken myosin heavy chain protein.

A genomic bank has been constructed using DNA isolated from a dystrophic strain of chickens. The library was screened for myosin heavy chain (MHC) sequences using a cDNA probe and 11 positive recombinants isolated. Identity of the clones was confirmed by positive RNA selection via hybridization of the clones with muscle RNA and subsequent translation of the hybridizable RNA in vitro. Restriction maps indicate that the clones can be divided into 7 distinct groups; some of these groups do, however, share similar or homologous sequences. Hydridization of the clones to RNA derived from leg, breast, heart, and brain reveals that all of the clones code for the muscle-specific MHC isoforms. These experiments also show that there are at least 3 size classes of MHC mRNA sequences, whose relative amounts appear to be modulated in a tissue- and developmental stage-specific manner.

Animals

Insulin and glucagon responses of transplanted intrasplenic pancreatic islets.

Two transplant procedures have been investigated in which one third of the pancreas was autotransplanted into the splenic pulp of dogs. The two procedures consist of simple mechanical dissociation of the pancreas or mechanical dissociation followed by collagenase digestion. The ability of the endocrine segment of the transplant to survive and function was assessed by stimulation with arginine and measurement of insulin and glucagon response. The results demonstrate that both transplant procedures result in functioning beta and alpha cells that rapidly secrete both insulin and glucagon in response to arginine stimulation. However, greater insulin responses were obtained when mechanically dissociated but nonenzyme digested pancreatic tissue was used for transplantation. The spleen appears to be an excellent transplant site for the reception of endocrine pancreatic tissue and allowed both beta and alpha cells to survive following transplantation.

Animals

Self-regulated methadone detoxification of heroin addicts. An improved technique in an inpatient setting.

We used a method of detoxifying heroin addicts involving a self-regulated schedule of methadone hydrochloride detoxification in an inpatient setting. This method allows the addict to receive methadone on an "as needed" basis within specified guidelines, thus permitting him to regulate his own detoxification. For this study, 30 chronic heroin addicts were detoxified using this self-regulated detoxification procedure. Measures of length of stay, amount of methadone required, and degree of patient satisfaction indicate that this is a practical means of withdrawing chronic heroin addicts that may have advantages over fixed withdrawal schedules.

Adult

A comparison between the gastric and salivary concentration of iodide, pertechnetate, and bromide in man.

The concentration of iodide (I(-)) and pertechnetate (TcO(4) (-)) and bromide (Br(-)) has been measured simultaneously in gastric juice and parotid saliva. The combined gastric and salivary clearance for iodide and pertechnetate is more than twice the clearance of these ions by the thyroid gland. The concentration of the ions was in the order I(-)>TcO(4) (-)>Br(-) in both gastric juice and saliva. Differences exist between the secretion of iodide, pertechnetate, and bromide. Bromide, in contrast to iodide and pertechnetate, was found to be more concentrated in gastric juice than in saliva. The ratio of the iodide to pertechnetate clearance was greater in gastric juice than in saliva.

Adult