PubMed Health⌕ Search

Biomedical subjects

G Paterson

Publications and source records attributed to G Paterson.

At least 19 recordsLinked to original sources

Self-reported effects of computer workshops on physicians' computer use.

BACKGROUND: The need for physicians to be proficient in the use of computers is undeniable. As computers have become easier to use and more widespread, their use in medicine is expanding. Several organizations have produced continuing medical education programs to teach physicians about the use of computers in medicine but little has been reported on the effects of such programs. METHOD: We present the self-reported effects of a series of workshops that taught physicians about basic computer skills: information retrieval, the Internet, CD-ROMs, electronic mail, and computer-aided learning. RESULTS: A questionnaire mailed to 65 workshop participants yielded a response rate of 46% (n = 30). Of the 30 respondents, 27% (n = 8) had bought new hardware or software because of attending the workshops, with the most common purchase being a new computer. Fifty-seven percent (n = 17) had increased their use of computers, with the most common applications being use of the Internet for information retrieval and electronic mail.

Computer User Training↗

Comparative levels of organochlorine compounds in flounders from the northeast coast of Newfoundland and an offshore site.

Muscle tissue of yellowtail flounder, Pleuronectes ferruginea (n = 6) and winter flounder, Pseudopleuronectes americanus (n = 9) collected from Bonavista Bay, Conception Bay and an offshore location off northeastern Newfoundland, Canada, were analyzed for PCBs and other organochlorine compounds to determine if there are geographical variations in the concentrations and patterns of these persistent contaminants. The concentrations of total PCB congeners on a wet weight basis were relatively homogeneous at low ng/g levels. DDE, HCH compounds, and components of technical chlordane were the dominant organochlorine contaminants. Lipid normalized data indicate that PCB concentrations were higher in both species collected in the moderately urbanized region of Conception Bay. Principal Component Analysis (PCA) of PCB congener patterns indicated that flounder collected in Conception Bay had greater proportions of highly chlorinated PCB congeners, which may indicate point-source contamination in this region. Concentrations and patterns of other organochlorine compounds were relatively consistent across all sampling locations.

Animals↗

Auscultation of the heart: a trial of classroom teaching versus computer-based independent learning.

Declining skills in auscultation of the heart prompted an evaluation of teaching methods for medical students. A comparison of classroom teaching and computer-aided independent learning of auscultation was carried out with two groups of approximately 20 second-year medical students. Both groups used approximately 20 recorded normal and abnormal heart sounds and murmurs, chosen to illustrate learning issues. For the classroom group a cardiologist presented each case through multiple stethophones and led the discussion. The individual study group used a new CD-ROM collection of cases and recordings in quiz format, with a hypertext link to a comprehensive text on auscultation and additional recordings. Students were tested with 16 multiple choice and 5 open questions on eight selected recordings, and evaluated the teaching by questionnaire. The classroom-taught students scored higher on open questions than the CD-ROM-taught group, but in general performance by both groups was satisfactory and equivalent. Students of both groups repeatedly had difficulty classifying regurgitant and ejection murmurs and identifying characteristics of the second heart sound. Both CD-ROM and classroom teaching methods were highly rated by students but most students preferred a combination.

CD-ROM↗

Mechanisms of action of anti-GM1 and anti-GQ1b ganglioside antibodies in Guillain-Barré syndrome.

Anti-GM1 and anti-GQ1b ganglioside antibodies are found in association with acute and chronic peripheral neuropathies, including Guillain-Barré syndrome. They are believed to arise as a result of molecular mimicry with immunogenic microbial polysaccharides. Although anti-ganglioside antibodies are suspected to play a causal role in neuropathy pathogenesis, the details of this have yet to be proven. The approach in this laboratory to solving this issue has been to generate anti-GM1 and anti-GQ1b monoclonal antibodies from peripheral blood lymphocytes of affected patients and to study their immunolocalization in peripheral nerve and their electrophysiologic effects in animal models in which peripheral nerve sites are exposed to anti-ganglioside antibodies. These data show that anti-ganglioside antibody-reactive epitopes are widely distributed in peripheral nerve and can cause electrophysiologic abnormalities in a variety of model systems; thus, these data support the view that anti-ganglioside antibody-reactive epitopes may directly contribute to neuropathy pathogenesis.

Animals↗

A somatically mutated human antiganglioside IgM antibody that induces experimental neuropathy in mice is encoded by the variable region heavy chain gene, V1-18.

IgM paraproteins associated with autoimmune peripheral neuropathy and anti-Pr cold agglutinins react with sialic acid epitopes present on disialylated gangliosides including GD1b, GT1b, GQ1b, and GD3. A causal relationship between the paraprotein and the neuropathy has never been proven experimentally. From peripheral blood B cells of an affected patient, we have cloned a human hybridoma secreting an antidisialosyl IgM mAb, termed Ha1, that shows identical structural and functional characteristics to its serum counterpart. Variable region analysis shows Ha1 is encoded by the same VH1 family heavy chain gene, V1-18, as the only other known anti-Pr antibody sequence and is somatically mutated, suggesting that it [correction of is] arose in vivo in response to antigenic stimulation. In the rodent peripheral nervous system, Ha1 immunolocalizes to dorsal root ganglia, motor nerve terminals, muscle spindles, myelinated axons, and nodes of Ranvier. After intraperitoneal injection of affinity-purified antibody into mice for 10 d, electrophysiological recordings from the phrenic nerve-hemidiaphragm preparation demonstrated impairment of nerve excitability and a reduction in quantal release of neurotransmitter. These data unequivocally establish that an antidisialosyl antibody can exert pathophysiological effects on the peripheral nervous system and strongly support the view that the antibody contributes to the associated human disease.

Amino Acid Sequence↗

Expression and secretion of recombinant ovine beta-lactoglobulin in Saccharomyces cerevisiae and Kluyveromyces lactis.

High expression and secretion of recombinant ovine beta-lactoglobulin has been achieved in the yeast Kluyveromyces lactis. The yield of beta-lactoglobulin is 40-50 mg per litre of culture supernatant and accounts for approx. 72% of the total secreted protein. Constitutive expression is under the control of the Saccharomyces cerevisiae phosphoglycerate kinase promoter from an intronless version of the beta-lactoglobulin gene. Secretion is specified by the ovine protein's own signal sequence. this system, coupled to an efficient and novel recovery protocol, allows 30 mg of pure protein to be isolated from a typical 1 litre culture. The protein is virtually indistinguishable from beta-lactoglobulin conventionally purified from sheep milk by its behaviour in native PAGE and SDS/PAGE, reactivity to antibodies, CD, fluorescence spectroscopy and N-terminal sequencing. Attempts to achieve a similar expression and secretion system in the yeast S. cerevisiae met with only limited success, although it was found that heat-shock treatment modestly increased the yield up to approx. 3-4 mg per litre of culture supernatant. Site-directed mutagenesis showed that secretion in S. cerevisiae depended upon correct formation of the two disulphide bonds present in beta-lactoglobulin.

Amino Acid Sequence↗

Analysis of anti-GM1 ganglioside IgM antibodies cloned from motor neuropathy patients demonstrates diverse V region gene usage with extensive somatic mutation.

Serum anti-GM1 ganglioside Abs are abnormally elevated in patients with chronic motor neuropathies and Guillain-Barré syndrome. We have cloned six anti-GM1 IgM Abs from PBMCs of five affected patients. VH and VL gene analysis demonstrated substantial somatic mutation, predominantly clustered around VH CDR2 and FR3 in all six Abs. The Abs SM1, DO1, and WO1, isolated from three different patients, are encoded by closely related VH gene segments with restricted canonical structures. The corresponding L chains are encoded by V lambda II and V lambda VIII genes and also share the same canonical structures, containing nucleotide deletions at the VL/JL boundary to form a VLCDR3 of 10 amino acids. DO1 and WO1 VH segments show nucleotide identities of 95.6% and 88.8%, respectively, to the VH3 member 1.9III, and SM1 shows 87.8% identity to the closely related VH3 member, Hv3005. The Abs BO1 and BO3, derived from a single patient and containing the same VH-D-JH and VL-JL rearrangements, are encoded by the VH3 gene, HHg19, with nucleotide identities of 92.2 and 91.2%, respectively, and have both common and unique somatic mutations. The VH sequence of BR1 has 91.3% identity to the VH4 member, V71-2. These data indicate that neuropathy-associated anti-GM1 IgM Abs can be encoded by both diverse and closely related V genes in association with restricted canonical structures, and that their V genes are somatically mutated, consistent with an origin through an Ag-driven immune response.

Amino Acid Sequence↗

Cloning of human anti-GM1 antibodies from motor neuropathy patients.

Patients with multifocal motor neuropathy frequently have elevated titers of serum antibodies reactive with GM1 ganglioside. Although these antibodies may cause the syndrome, this has yet to be proven directly. As part of our studies on the nature and pathogenic potential of anti-GM1 antibodies, we have cloned B cells from the peripheral blood of 3 patients with multifocal motor neuropathy and generated four stable heterohybridoma cell lines secreting human monoclonal IgM anti-GM1 antibodies. In this report we describe the basic properties of these monoclonal antibodies in comparison with the patient's sera from which they were derived. The antibodies all differ in their pattern of reactivity with GM1 and other Gal(beta 1-3)GalNAc-containing glycoconjugates. They have widely varying thermal ranges and their reactivities are strongly influenced by the presence of accessory lipids. Affinity purification of the patient's sera with GM1 led to the identification of previously unrecognized paraproteins that were resolvable above the background of polyclonal anti-GM1 IgM. Our data demonstrate considerable heterogeneity in the immune response to GM1 both within individual sera and between different patients, which is likely to be of importance to their role in disease pathogenesis.

Adult↗

Tobacco advertising in South Africa with specific reference to magazines.

RATIONALE: A ban on tobacco advertising forms an integral component of tobacco control strategies, and needs to be considered in South Africa as a matter of urgency. OBJECTIVES: To obtain baseline data on tobacco advertising expenditure in the South African media, and to compare brands used to target different groups in magazines. METHODS: Advertising expenditure (totals and tobacco-related) for 1991 and 1993 was obtained from Adindex. Ten magazines, each with circulations of over 100,000, directed at four different target groups, were selected. For 3 months in 1993, total and tobacco advertising expenditure, brand placement and magazine demographics were determined. RESULTS: Tobacco-related expenditure constituted 4.8% of the R3 billion spent on advertising in 1993. Print (including magazines) and radio together accounted for 72% of all tobacco advertising, while cinema and outdoor advertising were most dependent on the tobacco industry for revenue. Annualised advertising spending for the 10 magazines reached an estimated R230 million, of which tobacco 'adspend' accounted for 6.4%. The highest percentage of tobacco adspend (20.3%) was for a men's 'soft-porn' magazine. For 26 of 30 issues studied, tobacco adverts were on the back cover. Brand targeting was evident in black, women's, and family magazines. There was not a single feature article on the adverse effects of smoking on health in any of the magazines during the 3-month period. Only 2 magazines had single sentences in their health columns mentioning that smoking was bad for health. In a third magazine, one opinion piece devoted a full page to criticising the anti-tobacco lobby! CONCLUSION: Tobacco advertising, through radio and outdoor advertising, reaches children and illiterate communities in peri-urban and rural areas. Tobacco advertising in magazines targets specific consumers, such as blacks and women. For most magazines, tobacco adspend constitutes less than 10% of the total. A total ban on tobacco advertising in the media in general and certainly in magazines would not have adverse economic effects and would promote health.

Advertising↗

Antiglycolipid antibodies, immunoglobulins and paraproteins in motor neuron disease: a population based case-control study.

The role of humoral autoimmune factors in the pathogenesis of motor neuron disease (MND) is currently under considerable scrutiny. In particular, there have been many reports of abnormal serum immunoglobulin patterns and elevated titres of anti-ganglioside antibodies in patients with MND. However, many of these studies may be biased by the selection criteria for patients and controls. In order to carefully address this issue we obtained 82 blood samples from consecutive MND patients identified through a national MND register in combination with 82 community controls matched for age, sex and geographical area. We used these samples to determine the frequency of monoclonal immunoglobulins (mIgs) and measure the levels of serum immunoglobulins and anti-GM1 ganglioside antibodies in sporadic cases of MND in comparison with normal controls. Serum mIgs detected using high resolution and immunofixation agarose electrophoresis were present in 1.2% of MND patients and 2.4% of controls. Using a highly sensitive isoelectric focusing and immunoblotting method, monoclonal or oligoclonal immunoglobulins were found in 28% of MND patients and 27% of controls. Anti-GM1 antibodies were present in 26% of MND patients and 18% of controls (odds ratio = 1.5, 95%, CI 0.7-3.6) with no significant differences in titres between the 2 groups. Mean immunoglobulin G, A and M levels were equal in 2 groups. Thus, although alterations in these parameters were identified, we were unable to demonstrate any significant difference between MND patients and controls. We conclude that the majority of sporadic cases of MND are unlikely to have an autoimmune basis as judged by the lack of abnormalities in these parameters.

Adult↗

Peripheral neuropathy associated with monoclonal IgM anti-Pr2 cold agglutinins.

A patient with a chronic, large fibre sensory neuropathy had an immunoglobulin M lambda monoclonal paraprotein reactive at titres in excess of 1/10(5) with NeuNAc(alpha 2-8)NeuNAc(alpha 2-3)Gal configured disialosyl groups present on the gangliosides GD1b, GT1b, GQ1b, and GD3. The paraprotein showed weaker reactivity with GD1a, GM3, and LM1 but no reactivity with GM2, GM1, or asialo-GM1. In addition, the paraprotein had cold agglutinating activity with anti-Pr2 specificity, Pr2 being an antigenic determinant on membrane glycoproteins or glycolipids in erythrocytes or both. A large fibre sensory neuropathy with monoclonal anti-disialosyl antibodies is an increasingly recognised form of paraproteinaemic neuropathy.

Agglutinins↗

The real time analysis of sport: an overview.

This paper describes a specific system analytic approach to the coaching and teaching of team sports. Computer technology is used to acquire the sequential history of critical events that occur during competition. A system is described that allows the analyst to enter data directly on a microcomputer and then compute relevant statistics for immediate use by the coach or teacher. The implications for the microcomputer system's use in high performance sports is also discussed.

Computers↗

A model for comparison of local anesthetics in man.

Ten patients scheduled for bilateral arm surgery were given general anesthesia plus, on one side, an axillary brachial plexus block. Ten additional patients scheduled for bilateral foot surgery were similarly given general anesthesia plus an ankle block on one side. A within-patient blind comparison of postoperative analgesia between blocked and unblocked side was performed. An additional 10 patients scheduled for bilateral foot surgery had one side blocked with lidocaine and the other side blocked with bupivacaine for comparison of postoperative analgesia. Postoperative analgesia recorded by a nurse observed was significantly better on the blocked side compared with the unblocked side. This difference was greater for ankle blocks. There were no differences between the analgesic measures for lidocaine and bupivacaine ankle blocks over the 6-hour study period.

Adolescent↗

Sickle cell trait and diabetic retinopathy.

The presence of sickle cell trait and the prevalence and severity of retinopathy were assessed in 124 Negro diabetics. Sickle cell trait had no adverse effect on diabetic retinopathy.

Adult↗