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Biomedical subjects

S Cameron

Publications and source records attributed to S Cameron.

At least 127 records · Page 7Linked to original sources
PubMed1986

Tc-99m DTPA scans in renal allograft rejection and cyclosporine nephrotoxicity.

Renal allograft dysfunction arising from rejection or cyclosporine (CsA) nephrotoxicity can currently only be distinguished reliably by allograft biopsy. We have assessed Technetium (Tc)-99m diethylamine pentacetic acid (DTPA) scanning in 30 CsA-treated patients with allograft dysfunction. Scintigrams were performed during 20 biopsy-proved episodes of rejection and during 14 episodes of CsA nephrotoxicity. These results were compared with the scintigrams of 15 allografts showing stable function. Quantitative indices expressing allograft perfusion (flow index) and function (uptake index) derived from the DTPA scintigrams showed no significant differences between the groups of patients with rejection, CsA nephrotoxicity, or stable or improving function. Similarly, the flow and uptake indices of individual allografts obtained during periods of stable or improving function and then during episodes of dysfunction due to rejection or CsA nephrotoxicity did not significantly change. We conclude that Tc-99m DTPA scintigrams are of limited value in the management of allograft dysfunction in patients immunosuppressed with CsA.

Cyclosporins↗
PubMed1986

Exploring the function of RAS oncogenes by studying the yeast Saccharomyces cerevisiae.

The RAS oncogenes comprise a family of genes found to be activated in perhaps 10-20% of human cancers and which have been highly conserved in evolution. Homologs of the mammalian RAS exist in the yeast Saccharomyces cerevisiae (RAS1 and RAS2). We have shown that human ras proteins can complement the loss of RAS1 and RAS2 proteins in yeast, and hence are functionally homologous. Both human and yeast RAS proteins can stimulate the magnesium and guanine nucleotide-dependent adenylate cyclase activity present in yeast membranes. However, RAS proteins do not appear to stimulate adenylate cyclase in vertebrate cells. Our studies indicate that although RAS proteins are essential controlling elements of adenylate cyclase in yeast, they have other essential functions in that organisms. RAS proteins are themselves probably controlled by growth regulatory proteins.

Fungal Proteins↗
PubMed1985

Reduction of self-injurious behavior in an autistic girl using a multifaceted treatment program.

Self-injurious hand biting was reduced in an autistic girl by using fine water mist combined with a loud statement of "No!" following the behavior, and verbal praise for appropriate behavior. The subject was 6 years old when the interventions were implemented, and she had been in arm and head restraints since infancy. A fading procedure that moved from a large to smaller bottles allowed generalization across settings and people. Treatment was effective at a 6-month follow-up in both structured and unstructured settings.

Autistic Disorder↗
PubMed1985

Functional homology of mammalian and yeast RAS genes.

Yeast spores lacking endogenous RAS genes will not germinate. If such spores contain chimeric mammalian/yeast RAS genes or even the mammalian H-ras gene under the control of the galactose-inducible GAL10 promoter, they will germinate in the presence of galactose and produce viable haploid progeny dependent on galactose for continued growth and viability. These results indicate that the biochemical function of RAS proteins is essential for vegetative haploid yeast and that this function has been conserved in evolution since the progenitors of yeast and mammals diverged.

Animals↗
PubMed1985

In yeast, RAS proteins are controlling elements of adenylate cyclase.

S. cerevisiae strains containing RAS2val19, a RAS2 gene with a missense mutation analogous to one that activates the transforming potential of mammalian ras genes, have growth and biochemical properties strikingly similar to yeast strains carrying IAC or bcy1. Yeast strains carrying the IAC mutation have elevated levels of adenylate cyclase activity. bcy1 is a mutation that suppresses the lethality in adenylate cyclase deficient yeast. Yeast strains deficient in RAS function exhibit properties similar to adenylate cyclase deficient yeast. bcy1 suppresses lethality in ras1- ras2- yeast. Compared to wild-type yeast strains, intracellular cyclic AMP levels are significantly elevated in RAS2val19 strains, significantly depressed in ras2- strains, and virtually undetectable in ras1- ras2- bcy1 strains. Membranes from ras1- ras2- bcy1 yeast lack the GTP-stimulated adenylate cyclase activity present in membranes from wild-type cells, and membranes from RAS2val19 yeast strains have elevated levels of an apparently GTP-independent adenylate cyclase activity. Mixing membranes from ras1- ras2- yeast with membranes from adenylate cyclase deficient yeast reconstitutes a GTP-dependent adenylate cyclase.

Adenylyl Cyclases↗
PubMed1984

Vaccine prophylaxis of abattoir-associated Q fever.

Q fever is an important cause of morbidity in Australian meatworkers; recently there have been sharp outbreaks of Q fever in abattoirs in several states. In an attempt to control Q fever by vaccination, 924 nonimmune volunteers at two South Australian abattoirs were inoculated with one dose of a purified, formalin-inactivated, Coxiella burneti, Henzerling strain, phase 1 vaccine. Some 56% of workers in one abattoir, and 64% in the other, seroconverted after vaccination. In the 18 months after vaccination, no Q fever occurred in fully vaccinated subjects, whereas there were 34 cases in 1349 unvaccinated workers. Transient local reactions were noted in most vaccinated subjects; only a few had mild general reactions. No cases of vaccine-enhanced disease were observed. Vaccination of susceptible individuals with a purified C burneti phase 1 vaccine appears to be safe and effective in preventing Q fever in the abattoir.

Abattoirs↗
PubMed1982

Population-based comparative study of campylobacter and salmonella enteritis in South Australia.

A total of 658 cases of campylobacter enteritis was reported in South Australia in the 18 months from March, 1980. Although Campylobacter sp. may cause more gastrointestinal disease than Salmonella sp. during some time periods, our data suggest that the reverse applies over all. However, since campylobacter enteritis tends to affect older persons who possibly are investigated less frequently, the relative prevalence of campylobacter infection may have been understated. Both diseases are notified among preschoolers to a disproportionate extent; however, Campylobacter sp. show a greater predisposition that Salmonella sp. for affecting teenagers and young adults. Persons with campylobacter infection are more likely to be residents of metropolitan areas than their counterparts with salmonella enteritis. Virtually all persons with campylobacter infection experience some diarrhoea; three-quarters have abdominal pain; approximately one-third report blood, and a similar proportion mucus in their stools. Children are more likely than adults to have mucus, and possibly blood, in their stools.

Adolescent↗
PubMed1980

Pressurized contrast delivery for coronary arteriography.

A system is described for eliminating negative pressure source of air bubbles within a closed-circuit arrangement for dye delivery in coronary angiography. Replacing the usual manual pressure created by an aspirating syringe, this system pressurizes the reservoir bottle by means of a cuffed bag, double-lumen, one-way piercing spike and a 0.2 micron filter.

Angiocardiography↗
PubMed1979

O.B. staff alert.

Explore the source record for details and available documents.

Emotions↗
PubMed1978

Distribution of the crossed olivocochlear bundle in the chinchilla's cochlea.

The efferent crossed olivocochlear bundle (COCB) was transected in the brain stem of the chinchilla, and the animals sacrificed 7 to 96 days later. Electron microscopy revealed that all the large efferent nerve endings on outer hair cells in the basalmost 2 mm (round window region) of the cochlea had degenerated, 87.5% in the remainder of the first turn, 70% in the second turn and 43% in the third turn. Only a few degenerating nerve fibers were seen in the medial spiral tract (inner spiral and tunnel bundles) of the experimental animals. Nerve fibers were counted in the medial spiral tracts of the cochleas of control animals as well as in those animals whose COCB had been transected. There were considerable individual variations in the fiber numbers, and statistical analysis showed no significant difference between the numbers of nerve fibers in normal and experimental animals. The cochlear microphonics (CM) and nerve action potentials (AP) of acute animals were assessed before and after COCB section. The CM and AP of the chronic experimental animals were compared with responses from normals. Overall, no changes in a physiological response of the anesthetized chinchilla could be attributed to complete section of the COCB.

Acetylcholinesterase↗
PubMed1975

Dilatation of the parous non-pregnant cervix.

In vitro cervical dilatations were carried out on 33 uteri removed by hysterectomy for conditions not involving the cervix from parous women in their reproductive span of life. A specially designed force measuring dilator was used for all the tests. The analysis of the results involved the application of a thick-walled cylindrical stress determination technique. Using this approach it was possible to calculate quasi-elastic moduli for different degrees of dilatation and obtain theoretical distributions of radial and circumferential stress across the cervical wall. These results indicated a yielding of the cervical tissue at about 9 to 11 mm. dilatation in a significant number of cases.

Cervix Uteri↗
PubMedDate not supplied

What contribution can the Hachinski Ischemic Scale make to the differential diagnosis between multi-infarct dementia and primary degenerative dementia?

Five research studies in which clinical diagnoses using the Hachinski Ischemic Scale (HIS) underwent neuropathological verification were analysed. These studies reveal that the HIS differentiates between multi-infarct dementia (MID) and dementia of the Alzheimer type (DAT) with only limited accuracy. To some extent, there are considerable differences between the studies as regards the methodology and the patient population. However, there are indications that some items of the ischemic scale clearly distinguish between MID and DAT, whereas others hardly do so or some do not distinguish at all between these two conditions. If the HIS is revised according to the present findings, it can become a more valid differential diagnostic instrument. Such a diagnostic instrument which may be applied without any other technical equipment is required today, since epidemiological data and demographic prognoses show that the prevalence of dementing illnesses will markedly increase in the future.

Journal Article↗