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Biomedical subjects

S Atkinson

Publications and source records attributed to S Atkinson.

At least 109 records · Page 6Linked to original sources
PubMed1985

Ram-induced growth of ovarian follicles and gonadotrophin inhibition in anoestrous ewes.

Southdown ewes in mid-seasonal anoestrus were exposed to rams for 0 h (control group), 2 h, 24 h, 40 h, 3 days, 10 days or 20 days. Serial blood samples were then taken to determine LH and FSH levels. Ewes with greater than 24 h ram exposure were ovariectomized immediately after bleeding, and all follicles greater than 1 mm diameter were dissected from the ovaries and measured. LH basal concentrations and pulse frequency increased significantly within 2 h of ram introduction, but by 24 h fell, and then remained low. FSH concentrations fell within 2 h of ram introduction and remained low. Control group ewes (isolated) had no follicles greater than 4 mm diameter, whereas all ewes exposed to rams had large follicles, with CL or preovulatory follicles present at 40 h after ram introduction. Ram introduction was also associated with follicle recruitment (antrum formation to less than 2 mm). Follicular recruitment and development to the large follicle stage therefore occurred during a period of low plasma gonadotrophin levels and suppressed LH pulsing.

Anestrus↗
PubMed1985

Mental health advocacy: paradigm or panacea?

In May, 1982, the Ontario Minister of Health set out the bare essentials of a proposed advocacy program for psychiatric patients. In November, a Toronto family doctor, actively involved in civil rights issues, was appointed to develop and coordinate the program. In May, 1983, eleven advocates were appointed to advise and assist patients in each of the province's ten psychiatric hospitals. The advocates came from various backgrounds--legal, psychiatric nursing and social work, labour negotiation, pastoral and other public services. This paper describes the design, function and scope of Canada's first province-wide psychiatric patient advocate system and some major issues identified in the first year.

Goals↗
PubMed1984

Ophthalmopathic immunoglobulin in patients with Graves' ophthalmopathy.

An IgG which binds specifically to retro-orbital antigen has been detected in patients with Graves' ophthalmopathy. By means of an assay which detects ophthalmopathic immunoglobulin (OIg) in patients' serum with an antigen prepared from porcine retro-orbital muscle, levels of OIg above the normal reference range were found in 21 of 33 (64%) patients with active untreated ophthalmopathy, in 3 of 12 (25%) with active disease already receiving steroid treatment, and in 3 of 18 (16%) with longstanding inactive eye disease. OIg was found in only 1 of 22 thyroid patients without eye disease. There was no correlation of OIg with thyrotropin-binding-inhibiting immunoglobulin nor with thyroid microsomal antibody, and there was no clear association with thyroglobulin antibody. Ophthalmopathy seems to be distinct from Graves' hyperthyroidism and the autoimmune response is directed to retro-orbital antigens.

Animals↗
PubMed1984

A specific IgG in Graves' ophthalmopathy and its relation to retro-orbital and thyroid autoimmunity.

An IgG (ophthalmopathic immunoglobulin) that binds to retro-orbital antigen was identified in serum from patients with active Graves' ophthalmopathy, and its nature and specificity were investigated. Dose related binding of this immunoglobulin to retro-orbital antigens prepared from guinea pig harderian gland or porcine eye muscle was found, which could be abolished by prior incubation with antigen. The immunoglobulin did not bind to thyroid membranes, thyroid microsomes, or thyroglobulin or interact with liver, skeletal muscle, or fat membranes. Serum with high activity of thyrotrophin binding inhibiting immunoglobulin did not react with retro-orbital antigen, and this activity was not affected by preincubation of the serum with retro-orbital antigen. Thyroid stimulating hormone was also without effect on retro-orbital antigen. It is concluded that Graves' ophthalmopathy is associated with a specific ophthalmopathic immunoglobulin that reacts with retro-orbital antigen as distinct from thyroid antigens, and that the autoimmune response is directed towards retro-orbital antigens. This suggests that the ophthalmopathy is an entity distinct from autoimmune thyroid disease.

Adult↗
PubMed1984

Evidence that thyroid-stimulating antibody is produced in the thyroid gland.

The hyperthyroidism in Graves' disease results from the action of thyroid-stimulating antibodies (TSAb). The thyroid gland in Graves' disease shows diffuse lymphocytic infiltration, and after removal of the gland antibody titres usually decline and patients go into remission. It is postulated that the lymphocytes in the thyroid may be an important site of TSAb production. 10 patients with Graves' disease and 8 patients with other thyroid disorders were studied. Blood was taken during operation, but before thyroid mobilisation, from the thyroid vein and simultaneously from a peripheral vein. In patients with Graves' disease the concentration of TSAb activity in the thyroid vein was much greater than that in the peripheral vein. TSAb was not detected in either peripheral vein or thyroid vein samples in the other patients. The increase in TSAb concentration in the thyroid vein indicates production of antibodies by lymphocytes within the thyroid and could explain why removal of the thyroid results in disappearance of TSAb from the circulation.

Adult↗
PubMed1984

Screening for refractive errors in 6-9 month old infants by photorefraction.

The method of isotropic photorefraction has been used in a trial of refractive screening of 6-9 month old infants. Data are presented on the calibration of the method against retinoscopic measurements and its reliability. In photorefractive screening of 1096 infants under cyclopentolate cycloplegia 5% were found to be hypermetropic (over +3.5 D), 4.5% myopic, and 1.3% anisometropic (over 1 D). These refractive errors were confirmed on retinoscopic follow-up (with the exception of a few anisometropes). Follow-up of controls shows that one small refractive error was missed in 52 infants. We conclude that photorefraction is a valid and practical screening technique. Longitudinal study of infants with refractive errors will assess the value of early detection, in particular for prediction and prevention of strabismus.

Adult↗
PubMed1983

Specific epidermal growth factor receptors on porcine thyroid cell membranes.

Specific saturable receptors for epidermal growth factor (EGF) of high affinity (Ka 1.7 X 10(9) M-1) have been demonstrated on porcine thyroid membranes. Optimal conditions for EGF binding have been determined. TSH and other peptide hormones do not inhibit the binding of 125I-EGF and EGF does not inhibit 125I-TSH binding to thyroid membranes. The results suggest that EGF may be involved in the regulation of thyroid follicular cell growth and function.

Animals↗
PubMed1983

The assay of Graves' immunoglobulins: a comparison of different methods.

A multiplicity of techniques has arisen for the measurement of the immunoglobulins specifically associated with Graves' hyperthyroidism, which has led to difficulty in assessing the clinical significance of these immunoglobulins. In this study of untreated toxic Graves' disease we have taken two assays (LATS protector and thyrotrophin binding inhibiting immunoglobulin, TBII) which depend upon the measurement of binding to thyroid cell membranes, and correlated them with a bioassay which measures as the index of activity the biologically relevant end point of T3 secretion from thyroid tissue. The frequency of positive responses obtained with each method was similar to that of previous studies; combining the results a positive response was found in 100%. No significant correlation was found between any of these three assays. T3 to assess which method relates most closely to circulating thyroid hormone levels in vivo. A highly significant correlation was obtained for TSAb measured by T3 secretion with both total serum T3 and total serum T4 levels. A positive correlation was also found for LATS protector, but not for TBII. We conclude that although these assays are specific for Graves' immunoglobulins, they are measuring closely related but not identical immunoglobulin activities.

Adult↗
PubMed1983

Spastic diplegia among children of low and normal birthweight.

Data from a population-based Cerebral Palsy Register in Western Australia were analysed for children born between 1956 and 1975, and low birthweight (LBW) and normal birthweight (NBW) infants were compared. Control populations of similar birthweight to the cases were available from Western Australia live births. The incidence of spastic diplegia among LBW infants was higher than among those of NBW. The relative risk for LBW infants increased from 12- to 26-fold between 1961 and 1975, and those who previously would have died were surviving to be more severely disabled, both physically and intellectually. For LBW infants the risk of spastic diplegia increased both with increasing maternal age and with birth order; for NBW infants birth order was of main importance. LBW singletons, NBW twins and those born in rural hospitals had increased risk of spastic diplegia. More antenatal problems were seen in the LBW group, whereas the NBW group had higher rates of perinatal problems. Thus the groups may differ aetiologically, the LBW group having a greater likelihood of being damaged in utero, whereas the NBW group may have become brain-damaged as a result of traumatic deliveries.

Australia↗
PubMed1982

Effect of radioiodine on stimulatory activity of Graves' immunoglobulins.

The effects of 131I therapy on the activity of thyroid stimulating antibody (TSAb) and thyrotrophin binding inhibiting immunoglobulin (TBII) in nineteen patients with Graves' disease have been studied. Prior to 131I administration TSAb was detected in 84%, and TBII in 68% of patients. Following 131I administration TSAb and TBII were detectable in 100% of patients. The elevation 3 months after treatment of the means of both the TSAb and TBII indices for the group of nineteen patients was highly significant compared with pre treatment values. All the patients went into remission during the course of the study and the TSAb index declined in all patients, becoming undetectable in eleven; TBII also declined in most patients but remained detectable in thirteen. The study furthermore afforded the opportunity for a direct comparison of binding with stimulatory activity. These results show that after 131I therapy for Graves' hyperthyroidism there is a transient increase in TSAb as well as TBII, followed by a decline, and that the measurement of binding and stimulatory activities are in good general agreement.

Antibodies↗
PubMed1981

The stimulation of thyroid hormone secretion in vitro by thyroid-stimulating antibodies.

A new simple technique is described for the in vitro assay of thyroid-stimulating antibody (TSAb) in serum. Thyroid slices are incubated with serum in two-compartmental dialysis pot, followed by measurement of the thyroid hormone concentration in the dialysis fluid by RIA. Heat-inactivated normal serum applied directly to the tissue has no effect on the basal level of response. A dose-dependent relationship is demonstrated for both TSH and TSAb. Serum from patients with untreated Graves' hyperthyroidism is clearly shown to stimulate thyroid hormone secretion. Porcine thyroid tissue has been used and responds well to TSAb. This technique not only has the advantage of simple methodology, but also reflects the biological activity of TSAb. Therefore it will prove useful for further studies of the significance of TSAb and the pathogenesis of Graves' disease.

Animals↗
PubMed1977

Effects of septal lesions on shock thresholds in weanling male and female rats.

Twenty-four-day old weanling male and female rats were either lesioned in the septal area, gonadectomized, lesioned and gonadectomized, or untreated. Tests for reactivity to electric shock were conducted at 26 and at 40 days of age. Neither males nor females showed any effect of the lesions are measured by flinch and jump thresholds to electric shock immediately following surgery; both male and female lesioned groups showed a significant lowering of thresholds when tested at 40 days of age. The effects of septal lesions on response to electric shock were dissociated from the effects on hyperemotionality measured over the same period of time after the lesions, and appeared to have their effect independent of the sex or hormonal condition of the animals.

Animals↗
PubMed1976

Effect of isolation on barbiturate anaesthesia in the rat.

The duration of barbiturate-induced sleeping in rats was found to be reduced by isolation housing. It was also lower in males than females, and lower in the dark phase of the diurnal cycle. These variables were shown to be additive in their effects. Sex differences in barbiturate action were found to be reduced by gonadectomy in males; and the effects of isolation were found to depend upon housing conditions at the time of testing rather than upon early rearing environment. The implication for theories of arousal is discussed.

Anesthesia↗