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Biomedical subjects

S Lloyd

Publications and source records attributed to S Lloyd.

At least 109 records · Page 6Linked to original sources
PubMed1994

Lack of effect of lesions in the anterior cingulate cortex and retrosplenial cortex on certain tests of spatial memory in the rat.

The effects of cytotoxic lesions in either the anterior cingulate cortex or the retrosplenial cortex were compared with those of fornix lesions on three tests of spatial memory. Two of the tasks, delayed nonmatching-to-position and spatial reversal learning, were tested in an automated apparatus. The third task, forced alternation, was tested in a T-maze. Neither anterior cingulate nor retrosplenial cortex damage produced any significant impairment on the three tasks. In contrast, rats with fornix lesions (hippocampal system damage) were markedly impaired on all three tasks. The results, which were considered in the light of proposals for a hippocampal--anterior thalamic--cingulate system that is important for spatial memory, suggest that neither of the cingulate regions involved in this study form a critical subcomponent of this proposed system. It is therefore assumed that the cingulate cortices are only critical for certain classes of spatial problem. It is also suggested that in some previous studies the effects of inadvertent damage to the cingulum bundle may have contributed to the apparent effects of cingulate lesions.

Animals↗
PubMed1994

An unusual finding on routine dental pan-oral tomography.

Radio-opaque foreign bodies are commonly seen in dental pan-oral tomographs. A case is described of the presentation of a patient with a signet ring lodged in the left nasal cavity discovered by routine pan-oral tomography in dental practice, and of its subsequent removal by an otorhinolaryngologist.

Child↗
PubMed1994

The effect of serum and colostrum immunoglobulins from buffaloes infected with Toxocara vitulorum on T. vitulorum larvae in vitro and in vivo in mice.

Serum and colostrum were collected from adult buffalo cows naturally infected with Toxocara vitulorum. When injected into mice, the colostrum reduced the number of larvae of T. vitulorum that migrated in the mice. Injection of particularly the IgG-containing fraction but also the IgM-containing fraction of Sephadex G200-chromatographed colostrum also passively protected mice. When incubated for 6 h in buffalo serum or colostrum or fractions of these from Sephadex G200 and diethylaminoethanol Sephadex, T. vitulorum larvae had their activity in vitro curtailed. When the larvae were then fed to mice, their ability to migrate was markedly inhibited as compared with that of larvae that had been incubated in fetal calf serum or in helminth-free sheep colostrum. Fractions of serum and colostrum containing IgG1 had greater inhibitory effects both on the larvae in vitro and on their subsequent migration in mice than did IgG2-containing fractions. IgM also inhibited the larvae as 2-mercaptoethanol reduction of IgM in the IgM-containing peak eluted from Sephadex G200 reduced the inhibitory activity of this peak, although the activity was not completely abrogated.

Animals↗
PubMed1994

Periparturient reduction in buffalo of mitogen-induced lymphocyte proliferation and antibody to Toxocara vitulorum.

Lymphocyte and antibody reactivity were examined during the periparturient period in buffalo cows naturally infected with Toxocara vitulorum. Titres of antibodies to an extract of T. vitulorum larvae increased about 3 months before parturition. Antibody titres declined at about the time of parturition and remained low for up to 3 months into lactation. Lowered titres were found in the IgG class and not the IgM class of immunoglobulins. Levels of lymphocyte transformation induced by the mitogens concanavalin A and pokeweed mitogen declined markedly from one to 2 weeks before until one to 2 weeks after parturition. The relationship between this suppressed immunological reactivity and vertical transmission of T. vitulorum larvae is discussed.

Animals↗
PubMed1994

Toxocara vitulorum: maternal transfer of antibodies from buffalo cows (Bubalis bubalis) to calves and levels of infection with T vitulorum in the calves.

The levels of antibody to the excretory/secretory antigens of the infective larvae and adults of Toxocara vitulorum were measured by gel precipitation and ELISAs in the serum and colostrum of 12 buffalo cows naturally infected with T vitulorum and in the serum of their calves. The antibody levels were compared with the extent of T vitulorum infection as judged by faecal egg counts in the calves. The patterns of bands of the larval antigens and gel precipitating antibodies in cow serum taken one month before calving, in cow colostrum and in calf serum were very similar. Nine cows and their calves had gel precipitating antibodies but the remaining three cows and their calves did not. The ELISA detected anti-larval antibodies in the colostrum of all 12 cows and calves. With the exception of one calf there was a strong correlation (r = 0.902) between the antibody titre in cow colostrum and the titre of passively acquired antibody in calf serum. The titres of these passively acquired antibodies declined to their lowest levels in calves 12 to 25 days of age; the antibody concentrations then began to increase up to day 42 and remained stable for the remainder of the experiment (105 days). The titres of antibodies to the antigens of the adult worms, examined in four cows and their calves, were lower than the titres to the larval antigens; the calves absorbed this anti-adult antibody from the colostrum and the antibody levels reached a plateau between days 12 and 30 and remained stable for the rest of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Development of the emergency physician job satisfaction measurement instrument.

The objective of this study was to develop a valid and reliable instrument to measure the job satisfaction of physicians practicing emergency medicine. A prospective survey involving four separate stages (an item evaluation and reduction stage, a factor analysis stage, a construct validity stage, and a reliability stage) was distributed in Canada to full-time emergency physicians. Three separate survey instruments were administered (an initial draft instrument with 228 items, a pilot instrument with 142 items, and the final instrument with 79 items). Construct validity of the final instrument was tested by evaluating the correlation between physician scores on the instrument, and scores on two instruments measuring the same construct, and three measuring different but related constructs. A draft instrument with 228 items and six hypothetical domains was tested on 61 physicians. Evaluation for frequency endorsement, redundancy, and homogeneity reduced the item pool to 157. The remaining 157 items were used as a pilot instrument and tested on 223 physicians. Factor analysis eliminated 66 items from the pilot instrument, creating a final instrument with 79 items, 11 factors, and six domains. Cronbach's coefficient alpha for the final instrument domains is 0.81, and all domain-total correlations are greater than 0.4. All correlations between the final instrument and the construct validity instruments were statistically significant (P < .001), but not so high that they appeared to be measuring the same thing. Correlations between instruments measuring the same construct were higher than those measuring related but different constructs. Correlations between the final instrument and the CES-D scale, emotional exhaustion, and depersonalization subscales of the Maslach Burnout Inventory were negative. A test-retest reliability study on 42 physicians showed Pearson's correlation coefficients for individual domains were all greater than 0.7 and greater than 0.8 for the final instrument. This study has produced a valid and reliable instrument for measuring emergency physician job satisfaction, which is both internally consistent and stable.

Canada↗
PubMed1994

Family medicine residency programs. Evaluating the need for different third-year programs.

We asked hospital chief executive officers (CEOs) and District Health Council executive directors (DHCs) to compare third-year family medicine residency programs and judge which are more needed in their communities. Care for the elderly and emergency medicine ranked highest among CEOs, while DHCs ranked care for the elderly and mental health highest. Academic family medicine and northern programs ranked lowest for both groups.

Attitude of Health Personnel↗
PubMed1994

Teaching parents to look after children's teeth.

Children's toothpastes with fluoride help to prevent decay, but parents should ask their dentist before giving fluoride supplements to children. Overdosage is harmful. Sugars eaten as part of a meal do less harm to teeth than those eaten frequently as snacks. Sugar-free infant drinks and children's confectionery are now on the market and are more "tooth friendly". Look out for the "happy tooth" symbol. Babies can be registered with NHS dentists as soon as the first teeth start to come through, and should be taken regularly to the dentist throughout childhood. Under the NHS scheme, dentists are paid a capitation fee to provide continuing preventive care and treatment for children free of charge.

Adolescent↗
PubMed1993

Advanced prostate cancer. The role of high priced hormone therapy.

OBJECTIVE: To compare the costs of the various options presently available in Australia for treatment of advanced prostatic carcinoma by androgen deprivation. DESIGN: Forty patients underwent a bilateral orchidectomy for prostatic carcinoma during the 1990/91 financial year at the Princess Alexandra Hospital, Brisbane. The Yale Cost Model, as adapted for use in Australian case-mix projects, was used to derive a diagnosis related group (DRG) cost for this procedure. This was compared with the projected cost that would be incurred in treating patients with the various medical alternatives. To enable comparison, expenses were calculated assuming a mean duration of survival of two years. RESULTS: The average cost of a bilateral orchidectomy was $2869. This compared to $11,253 for goserelin and $12,329 for cyproterone acetate when used alone in treating a single patient. Flutamide is presently only approved for combination therapy with a luteinising hormone-releasing hormone agonist, and when used with goserelin an average cost of $16,148 per patient was projected. CONCLUSIONS: Bilateral orchidectomy is clearly the cheapest means of hormone manipulation for prostatic carcinoma. Unless the costs of alternative therapies are drastically reduced in Australia, their use is difficult to justify in other than exceptional circumstances. We believe their use should be restricted presently to patients who would otherwise require a bilateral orchidectomy and have an anticipated survival of less than six months.

Combined Modality Therapy↗
PubMed1993

The B cell dependence of Haemonchus contortus antigen-induced lymphocyte proliferation.

The proliferative responses of ovine lymphocytes to soluble antigens of third-stage larvae of Haemonchus contortus (HcAg) were examined in vitro. Lymphocytes in mononuclear cell cultures responded consistently to HcAg even if the lambs were naive to H. contortus. Lymphocytes from sheep that were immune to reinfection with H. contortus also consistently responded to HcAg with a response significantly greater than that recorded from naive lambs. When the responses of T cell or B cell enriched fractions were examined, neither enriched cell population responded to HcAg, even though the T cell populations were shown to contain monocytes by histochemistry. Studies using the accessory cell dependent T cell mitogen Con A demonstrated that such T cell enriched populations had normal Con A-induced responses compared to unfractionated mononuclear cells. In addition, neither the T cell nor B cell fractions responded to HcAg in the presence of autologous mononuclear cells which contained monocytes and dendritic cells. Responses to HcAg in the T cell enriched population were restored, however, by the presence of mononuclear cells that were cultured with HcAg for 48 hours and then irradiated before the addition of the T cells. These results were seen with cells from both H. contortus naive lambs and immune sheep. This provides evidence that B cells and not dendritic cells or monocytes are acting as antigen presenting cells in Haemonchus antigen-induced lymphocyte responses in both naive lambs and immune sheep.

Animals↗
PubMed1993

The same fractions of Haemonchus contortus soluble antigen induce lymphocyte responses in naive lambs and immune sheep.

Soluble antigen extracted from third stage larvae of Haemonchus contortus was divided into fractions based on molecular weight by sodium dodecyl sulphate polyacrylamide gel electrophoresis and electrotransferred to nitrocellulose. Infection immunised adult sheep and H contortus naive lambs were used to examine the lymphocyte responses to these fractions in vitro. The results demonstrate that the same two fractions induced the strongest responses in both groups of animals.

Animals↗
PubMed1993

Demographic characteristics of full-time emergency physicians in Canada.

The objective of this study was to describe individual and practice characteristics of Canadian emergency physicians, and to determine if these characteristics varied with geographic region, type of certification, or method of reimbursement. The study took place in emergency departments across Canada, and all full-time physicians with certification in emergency medicine, and a random sample of Canadian Association of Emergency Physician members without certification were surveyed with a 23-item questionnaire. Descriptive statistics on individual and practice characteristics were outcome measures. Comparative statistics evaluating demographic characteristics by region, type of certification, and method of reimbursement were used. There were significant differences between responders and nonresponders based on certification (P < .001) and region of residence (P < .005). Most physicians are male (87.3%), married (83.3%), reimbursed on a fee for service basis (61%), work in teaching hospitals (65.8%), and participate in medical education (82.3%). On average physicians are 38 years of age, work of 14 shifts/month, 9 hours/shift, 11 nonclinical emergency related hours/week, and have 5 vacation weeks/year. More physicians with FRCP(EM) certification work in teaching hospitals (P < .00001), do nonclinical emergency related work (P < .0001), participate in medical education (P < .0001), and are involved in research (P < .001). There are significant differences by geographic region in gross annual salary (P < .00001), method of reimbursement (P < .00001), and independent hospital emergency department status (P < .00001). Fee-for-service reimbursement for clinical service provides a higher gross annual income than other methods (P = .028). Emergency medicine is an emerging clinical discipline with a strong academic focus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Matching-to-sample deficits in patients with senile dementias of the Alzheimer and Lewy body types.

Using a computerized matching-to-sample task, nonverbal visual recognition memory was studied in two groups of patients suffering from senile dementia of the Alzheimer type or the recently described senile dementia of the Lewy body type. The patients' cognitive abilities had been shown to be similar according to a number of standard psychometric tests. The two groups did not differ with respect to simultaneous matching-to-sample performance, although both were impaired relative to control. The group with senile dementia of the Lewy body type was severely impaired, relative to the group with senile dementia of the Alzheimer type, when delays (delayed matching to sample) were introduced. The findings suggest that short-term mnemonic processes, mediated by temporal lobe structures, could be more severely affected in senile dementia of the Lewy body type.

Aged↗
PubMed1992

Antigen-induced protection against infection with Toxocara vitulorum larvae in mice.

Larvae of Toxocara vitulorum hatched and migrated in the tissues of normal mice. Larvae survived in reasonable numbers, particularly in the liver and, to a lesser extent, in the lungs and kidneys, for at least 4-7 days and in muscles, albeit only in low numbers, for at least 3 weeks. Oral infection of mice on three or more occasions with T. vitulorum eggs induced protection against a challenge infection with eggs of T. vitulorum. Prior parenteral immunization of mice with a variety of T. vitulorum soluble antigens (extracts, excretions/secretions, or perienteric fluid and their fractions) from adult parasites and/or infective larvae induced statistically significant protection against infection. The most effective protective immunogens were three or more injections with perienteric fluid from adults (100% protection) and excretions/secretions from infective larvae of T. vitulorum (> 92% protection).

Animals↗