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Biomedical subjects

T Stelmasiak

Publications and source records attributed to T Stelmasiak.

At least 19 recordsLinked to original sources
PubMed2006

A unified hypothesis of coeliac disease with implications for management of patients.

This mini-review presents the research carried out within the context of two of the main hypotheses of the aetiology of coeliac disease. The enzymopathic hypothesis of the disease has been placed clearly as the underlying deficiency causing increased levels of toxic peptides, while the immunological hypothesis has been implicated in the pathogenesis of the disorder as the result of the action of undigested peptides in the small intestine. As a consequence, we are proposing a unified hypothesis of coeliac disease, which takes into account the actions of these undigested peptides through their direct cytotoxicity and their immunoactivity. At the same time, work aimed at defining some of these biologically active peptides, which could be said to be involved in the aetiopathogenesis of coeliac disease, will be reported. The review also focusses on the use of enzyme therapy for management of the disease, which when used in conjunction with the gluten-free diet, offers a safeguard against damage to the small intestine caused by small amounts of gluten.

Celiac Disease↗
PubMed1988

Consistent capacity for adrenocortical response to ACTH administration in pigs.

The effect of ACTH administration on plasma cortisol concentrations in purebred and crossbred pigs was investigated. Pigs were given either 25 IU of ACTH or physiologic saline solution IM. Blood samples were collected immediately before and 1 hour after ACTH or saline solution administration. Administration of ACTH resulted in a significant (P less than 0.01) increase in plasma cortisol concentration compared with that resulting from administration of saline solution; mean values after ACTH administration were similar in both breed groups. In contrast, a fivefold range of differences was observed among individual pigs of the same age, sex, and body weight, irrespective of breed group. The type and magnitude of the adrenocortical response was consistent and repeatable in pigs over a 3-month period, suggesting that pigs have a consistent capacity for adrenocortical response to ACTH administration. Development of a dynamic test allowed the high and low responding extremes in a population to be detected. The most suitable dose of synthetic ACTH was established to be 50 IU, and the best time for blood sample collection was 60 minutes after ACTH administration. The classification of individual pigs as high or low responders was repeatable and was not affected by prior short-term exposure to ACTH.

Adrenocorticotropic Hormone↗
PubMed1986

Incidence of a heterosis effect in adrenal responsiveness to ACTH stimulation in the chicken.

No differences exist between basal plasma corticosterone concentrations of broilers ferals and first generation large crossbreds (White leghorn x New Hampshire). Crossbreds show near double adrenal responsiveness to synthetic ACTH administration, indicating a heterosis effect for this characteristic. Extraction of chicken plasma with 30% aqueous polyethylene glycol solution eliminates the need for tedious and expensive pre-assay purification of plasma.

Adrenal Glands↗
PubMed1986

Seasonal variation in plasma testosterone, luteinizing hormone concentrations and LH-RH responsiveness in mature, male rusa deer (Cervus rusa timorensis).

Plasma testosterone and luteinizing hormone (LH) concentrations in immobilized or yarded rusa stags (Cervus rusa timorensis) were investigated over a two-year period. Testosterone concentrations showed a minor elevation in autumn (May) and reached maximal levels in late winter-early spring (August) coinciding with the rut. Luteinizing hormone in plasma was only detectable from January to May. Maximal responsiveness of the pituitary-gonadal axis to LH-RH stimulation was recorded in August. The combination of Fentaz (fentanylcitrate and azaperone) and Rompun (xylazine hydrochloride) for immobilizing deer influences hypothalamic function.

Acclimatization↗
PubMed1985

Changes in plasma levels of cortisol and corticosterone after acute ACTH stimulation in rusa deer (Cervus rusa timorensis).

Resting cortisol and corticosterone levels in immobilized mature rusa stags (Cervus rusa timorensis) and the influence of synthetic ACTH on the cortisol/corticosterone ratio (F/B ratio) were investigated. The basal concentration of cortisol was found to be 14.07 nmol/l (SD = 9.3, N = 15) and corticosterone was 3.79 nmol/l (SD = 2.3, N = 15). The cortisol/corticosterone ratio for the basal level was 5.31 (SD = 3.9, N = 15). After ACTH administration the cortisol/corticosterone ratio increased to 11.41 (SD = 5.4, N = 147) regardless of doses of ACTH administered to individual stags. The adrenal response to ACTH administration has a potential application for selection of deer most suitable for deer farming.

Adrenocorticotropic Hormone↗
PubMed1984

Adrenal response to ACTH stimulation in Rusa deer (Cervus rusa timorensis).

Resting cortisol values in immobilized mature Rusa stags (Cervus rusa timorensis) and the response to synthetic ACTH were investigated. The mean level of cortisol in mature Rusa stags was found to be 3.80 ng/ml (SD = 0.87, N = 18). Over the range 0.37-6.0 i.u. the adrenal response to ACTH challenge was linearly related to the log dose ACTH administered (r = 0.998). More than 6 i.u. of ACTH caused maximal stimulation of the adrenal gland. Rusa deer appear to be much more sensitive to ACTH administration than other species.

Adrenal Glands↗
PubMed1984

The effect of immobilizing drugs on adrenal responsiveness to ACTH in Rusa deer.

Resting cortisol values in a fully tame Rusa deer (Cervus rusa timorensis) and the influence of two anaesthetics, Rompun and Fentaz, on cortisol levels as well as the response to synthetic ACTH were investigated. The mean level of cortisol in a completely tame Rusa deer was found to be 2.22 ng/ml (SD 1.45 ng/ml n = 36; minimal level recorded was 0.96 ng/ml, maximal level recorded was 9.21 ng/ml). No circadian rhythm of cortisol in plasma was detected. Rompun (xylazine hydrochloride) and/or Fentaz (fentanyl citrate) alone or in combination can be used for immobilization of Rusa deer. Neither Rompun nor Fentaz alone or in combination influences the cortisol response to synthetic ACTH administration. Because of the narrow range for safe dosage for Fentaz the use of Rompun for immobilizing deer is recommended.

Adrenal Glands↗
PubMed1983

Suppressed release of LH in ovariectomized post-partum ewes.

The patterns of LH release were studied in 5 ewes, ovariectomized when 3 days post partum, at 4, 14, 33, 47 and 61 days after ovariectomy. These patterns were compared with those in 4 seasonally anoestrous (control) ewes ovariectomized and sampled at the same times. In the control ewes regular pulsatile release of LH was apparent 4 days after ovariectomy: plasma LH concentrations and LH pulse frequencies, but not pulse amplitudes, then declined. In the post-partum ewes all indices of LH release were lower than those in the control ewes at 4 days after ovariectomy, but then they increased: pulse amplitude was greater (P less than 0.05) at 14 days after ovariectomy, and plasma LH concentrations were greater (P less than 0.05, 0.01) at 14 and 33 days than in control ewes. These results indicate that the hypothalamopituitary axis of lactating ewes has a reduced capacity to release LH for only a short period after ovariectomy early in the post-partum period. This probably reflects the time needed for recovery from the inhibitory effects of ovarian and placental hormones, and may reflect reduced secretion of LH-RH.

Animals↗
PubMed1982

Stress by immobilization, with food and water deprivation, causes changes in plasma concentration of triiodothyronine, thyroxine and corticosterone in poultry.

Measurements were sought for assessment of stress during investigations of welfare in intensively housed poultry. Immobilization was used as a stressor in experiments involving 64 cockerels of various ages. Two parameters were found to be related to acute stress: plasma triiodothyronine (T3) concentration, which fell markedly, and plasma corticosterone concentration, which rose considerably, in all birds during severe stress. Concurrently, plasma thyroxine (T4) concentration also fell in most, but not all, birds. Thyrotrophin releasing hormone (TRH) injected intravenously after immobilization caused increases in T3 and T4 levels, suggesting that the fall in T3 and T4 during acute stress was not caused by exhaustion of hormone production by the thyroid gland but rather by inhibition of release of TRH at the hypothalamic level.

Age Factors↗
PubMed1980

Pituitary responsiveness to LH-RH in post-partum ewes treated with oestradiol-17 beta and failing to show a plasma LH surge.

Oestradiol-17 beta (40 micrograms intravenously) failed to elicit a surge in plasma LH levels by 13 h after administration in 64% (16 out of 25) Merino ewes about 30 days post partum in the anoestrous season. LH-RH responsiveness and LH-RH priming effect were significantly greater in these ewes than in similar post-partum (n = 9) and non-parturient ewes (n = 3) not treated with oestradiol. This suggests that the failure of the oestrogen-positive feedback effect on LH release in post-partum ewes is not due to a failure of oestradiol action on the pituitary increasing pituitary responsiveness to LH-RH and LH-RH priming effect, but could be due to inadequate release of LH-RH from the hypothalamus.

Animals↗