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Biomedical subjects

L Williamson

Publications and source records attributed to L Williamson.

At least 55 records · Page 3Linked to original sources
PubMed1991

A pilot study of antithrombin replacement in intensive care management: the effects on mortality, coagulation and renal function.

A prospective, randomized, controlled trial to examine the effects of antithrombin supplementation on mortality, coagulation and renal function has been carried out on 132 intensive care patients. Antithrombin activity was measured in all patients on admission to the intensive care unit (ICU). Patients with an antithrombin activity of less than 70% were randomized to either receive antithrombin replacement or to act as controls. Antithrombin activity was maintained above 70% in the treated patients throughout their stay on ICU. Ninety-three patients had an antithrombin activity of less than 70% and 35 received replacement therapy. Patients with antithrombin activity below 70% remained on the ICU significantly longer and had a significantly higher mortality rate than patients with antithrombin activity above 70%. Antithrombin supplementation neither reduced mortality nor shortened the intensive care stay. Fifty patients with reduced antithrombin activity remained on the ICU for at least 4 days, 25 received antithrombin and 25 acted as controls; coagulation parameters and renal function have been monitored in these patients. Fibrinogen concentration and platelet count were unaffected by antithrombin replacement. Antithrombin supplementation did not appear to reduce the incidence of impaired renal function in sepsis, trauma and postoperative patients. The creatinine clearance fell below 20 ml/min in eight patients in the no-treatment arm while by comparison only three patients in the treatment arm developed impaired renal function. Our study does not demonstrate a clear role for the use of antithrombin supplementation in intensive care, however the finding that antithrombin reduced renal impairment is encouraging and a larger study to confirm this finding is at present underway.

Adult↗
PubMed1990

N-acetylaspartylglutamate: a transmitter candidate for the retinohypothalamic tract.

The retinohypothalamic tract is the neural pathway mediating the photic entrainment of circadian rhythms in mammals. Important targets for these retinal fibers are the suprachiasmatic nuclei (SCN) of the hypothalamus, which are thought to be primary sites for the biological clock. The neurotransmitters that operate in this projection system have not yet been determined. Immunohistochemistry and radioimmunoassay performed with affinity-purified antibodies to N-acetylaspartylglutamate (NAAG) demonstrate that this neuron-specific dipeptide, which may act as an excitatory neurotransmitter, is localized extensively in the retinohypothalamic tract and its target zones, including the SCN. Optic nerve transections resulted in significant reductions in NAAG immunoreactivity in the optic chiasm and SCN. Analysis of NAAG concentrations in micropunches of SCN, by means of radioimmunoassay, showed approximately 50% reductions in NAAG levels. These results suggest that this peptide may act as one of the neurotransmitters involved in retinohypothalamic communication and circadian rhythm entrainment.

Animals↗
PubMed1988

Food craving, mood and the menstrual cycle.

Seventy-six women, with a mean age of 35.7 years, who reported premenstrual craving for sweet foods in a retrospective questionnaire, were assessed prospectively with a pre- and post-menstrual eating questionnaire and daily ratings of craving, mood, irritability and breast tenderness over two menstrual cycles. In 72% of these women a perimenstrual pattern of food craving was confirmed. In 13% this craving was confined to the menstrual phase. There was no consistent association between food craving and mood change, either in timing or severity. Women with more severe mood change did not report more severe craving. There was also no association between food craving and cyclical breast tenderness. Perimenstrual food craving, therefore, appears to be a cyclical phenomenon in its own right, of uncertain aetiology and worthy of further study.

Adult↗
PubMed1985

Extracts of feverfew inhibit granule secretion in blood platelets and polymorphonuclear leucocytes.

Extracts of feverfew (Tanacetum parthenium) inhibited secretory activity in blood platelets and polymorphonuclear leucocytes (PMNs). Release of serotonin from platelets induced by various aggregating agents (adenosine diphosphate, adrenaline, sodium arachidonate, collagen, and U46619) was inhibited. Platelet aggregation was consistently inhibited but thromboxane synthesis was not. Feverfew also inhibited release of vitamin B12-binding protein from PMNs induced by the secretagogues formyl-methionyl-leucyl-phenylalanine, sodium arachidonate, and zymosan-activated serum. Feverfew did not inhibit the secretion induced in platelets or PMNs by the calcium ionophore A23187. The pattern of the effects of the feverfew extracts on platelets is different from that obtained with other inhibitors of platelet aggregation and the effect on PMNs is more pronounced than has been obtained with very high concentrations of non-steroidal anti-inflammatory agents.

Blood Platelets↗
PubMed1982

Conformational-energy studies of tetrapeptide opiates. Candidate active and inactive conformations.

The conformational behavior of four tetrapeptide enkephalin analogues (Tyr-Gly-Gly-Phe-OH, Tyr-Gly-Gly-Phe-NH2, Tyr-D-Ala-Gly-Phe-NH2, and Tyr-D-Ala-Gly-(NMe)Phe-NH2) was examined to identify conformations that are active and inactive at the opiate analgesic receptor. By using an empirical energy program, conformational energies were obtained for the optimized geometries of each tetrapeptide. Two methods of selecting candidate active conformations from low-energy conformers were used. In the first method, inactive conformers were designated as low-energy conformations of the very weak tetrapeptide, Tyr-Gly-Gly-Phe-OH. These candidate inactive conformers had geometries resembling beta V, beta I, "random" peptide conformations. Candidate active conformers selected were low-energy conformations found for both Tyr-D-Ala-Gly-Phe-NH2 and Tyr-D-Ala-Gly-(NMe)Phe-NH2 but not low-energy conformers for Tyr-Gly-Gly-Phe-OH. In the second method of selection, conformers with relative energies in the active and inactive peptides that followed the potency order Tyr-Gly-Gly-Phe-OH much less than Tyr-D-Ala-Gly-Phe-NH2 less than or equal to Tyr-D-Ala-Gly-(NMe)Phe-NH2 were chosen as candidate active conformers. By using both methods of selection, a beta II' bend geometry was found as the active conformer. This beta II' conformer was not stabilized by a 1-4 hydrogen bond, but instead was stabilized by a hydrogen bond between the tyrosine amine hydrogen atom and the phenylalanine carbonyl oxygen atom. The effect of C-terminal amide derivitization on peptide conformation was also examined by comparing the conformational profiles of Tyr-Gly-Gly-Phe-OH and Tyr-D-Ala-Gly-Phe-OH with their amides Tyr-Gly-Gly-Phe-OH-NH2 and Tyr-D-Ala-Gly-Phe-NH2. No significant difference in conformational behavior was found for the Tyr-Gly-Gly-Phe pair; however, a difference in conformational behavior was found between the Tyr-D-Ala-Gly-Phe acid and amide. Thus, on the basis of conformational data, the Tyr-Gly-Gly-Phe-NH2 analogue is predicted to have very weak opiate activity.

Amino Acid Sequence↗
PubMed1980

Sister chromatid exchange and chromosome aberration rates in a group of psoriatics before and after a course of PUVA treatment.

Blood was cultured and chromosome preparations were examined for sister chromatid exchanges and chromosome aberrations in eighteen patients receiving photochemotherapy with 8-MOP and UV-A for the treatment of psoriasis, both before starting treatment and again 6 months later. The UV-A was administered both by means of low output (irradiance: 1.1--2.25 mW/cm2) and high output (irradiance: 6.1--7.6 mW/cm2) UV-A radiation cubicles. Irrespective of the intensity of irradiation or the total dose of UV-A administered there was no evidence of chromosome damage in lymphocytes following treatment.

Adult↗
PubMedDate not supplied

Accessing residential care from an acute hospital: can we be more efficient?

Hospitalized patients who require admission to residential care are often thought to make prolonged and inappropriate use of hospital resources. There are no Australian data on the factors that contribute to length of hospital stay for such patients. The aim of this study was to determine the timing of critical steps in discharge planning for hospitalized patients who need residential care. We prospectively audited 100 consecutive referrals to an Aged Care Assessment Team (ACAT) from one acute hospital in South Australia. Case notes were examined to determine the timings of critical events in discharge planning. We found 47% of patients were discharged to a nursing home, 16% to a hostel, 11% died, 10% returned home and 16% went to another facility. The average length of hospital stay was 27.2 days, and an average of 8.4 days elapsed before a decision to seek residential care was first recorded. A further 4.5 days elapsed before ACAT referral, 4.6 days before ACAT approval and 9.7 days before a residential care bed became available. We conclude that people admitted to our hospital from the community and who subsequently need residential care, spend 36% of their stay awaiting a residential care bed. Most of their hospital stay has elapsed before residential care is considered necessary and referral and approval processes have been activated. Strategies to reduce length of stay should perhaps focus on the earlier recognition of the need for residential care and accelerated referral and assessment processes. Earlier involvement by social work and occupational therapy should be considered.

Aftercare↗
PubMedDate not supplied

Perimenstrual complaints in women complaining of PMS, menorrhagia, and dysmenorrhea: toward a dismantling of the premenstrual syndrome.

Four groups of women were compared in terms of their perimenstrual symptoms, reported menstrual blood loss and period pain, and neuroticism scores: three patient groups were referred to a Gynaecology Outpatient Clinic because of menorrhagia (N = 101), PMS (N = 104), dysmenorrhea (N = 56), and a control group (N = 105). The three patient groups showed considerable overlap in a number of symptoms. This has led us to postulate three factors contributing to perimenstrual complaints: a) a 'timing factor' linked to the ovarian cycle; b) a 'menstruation factor,' associated with the buildup of the endometrium and its shedding; and c) a 'vulnerability factor,' one aspect of which, 'neuroticism,' was measured in this study. Depressive symptoms, which were the most important in leading women to seek help for their PMS, were related to all three factors. Depressive mood changes seemed to be linked to the 'timing factor' but were noticeably worse and more prolonged in women with high neuroticism, heavy bleeding, or severe pain. One premenstrual symptom, food craving, was of considerable interest. This was weakly related to neuroticism, not apparently affected by the 'menstruation factor' and differed in severity between those in the PMS group and the other three groups. It is potentially relevant that both carbohydrate craving and depression are linked to serotonergic changes in the brain, which may prove to be particularly marked in the late luteal phase.

Adolescent↗
PubMedDate not supplied

Use of in-patient hospital beds by people living in residential care.

BACKGROUND: There is concern that people living in residential care in Australia make significant and often inappropriate use of acute in-patient hospital services. To date, no factual information has been collected in Australia and its absence may allow myths and negative stereotypes to proliferate. OBJECTIVE: To determine how and why people living in residential care in Australia use in-patient hospital beds. To determine the outcome of hospitalisation and functional status at 3 months following discharge. METHODS: Prospective study of 184 consecutive admissions to hospital following Emergency Department (ED) attendance involving people aged over 65 years and living in residential care in southern Adelaide, South Australia. Information was obtained from the facilities' transfer letters, and where these were inadequate or absent, telephone interviews were held with residential care staff. RESULTS: 153 people accounted for the 184 admissions. They had a mean age of 84 years and 69% were female. 61% came from hostels and 35% from nursing homes. They had a wide range of clinical problems and twice as many were admitted to medical than to surgical units. Their mean length of hospital stay was 7.9 days, 2.3 days higher than for non-same-day patients and was higher for hostel than for nursing home residents. All but two admissions were considered unavoidable though the provision of specialised care within residential care could have prevented a further 19 (10%) admissions. 96% of admissions resulted in survival to leave hospital and in 74%, people returned directly to their place of origin. At 3 months follow-up, a further 20% of the group had died while 5% were in hospital. In all, 14% of the original group were in a different long-term care facility while 56% were living at their former residence. CONCLUSIONS: People living in residential care are often hospitalised because of acute illness. In the vast majority of cases hospitalisation is both appropriate and unavoidable. Most did not require prolonged hospitalisation and were discharged alive, usually to their original residence. However, within 3 months many had died or had functionally declined. Strategies that prevent health breakdown in the residential care setting need to be developed and trialed.

Age Distribution↗