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Biomedical subjects

S Atkinson

Publications and source records attributed to S Atkinson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Membrane-type matrix metalloproteinases 1 and 2 exhibit broad-spectrum proteolytic capacities comparable to many matrix metalloproteinases.

Soluble proenzyme forms of the catalytic domains of membrane-type matrix metalloproteinases 1 and 2 (MT1-MMP and MT2-MMP) and a form of MT1-MMP containing the catalytic and hemopexin domains were expressed as soluble recombinant proteins. Purified, activated forms of the MT-MMP were shown to degrade fibronectin, tenascin, nidogen, aggrecan and perlecan. Only MT2-MMP showed activity against laminin. MT1-MMP retaining the hemopexin domain was able to specifically cleave native type-I and type-III collagens into the 3/4-1/4 fragments typical of the specific collagenases. The catalytic domain alone did not retain this activity. The MT-MMP did not degrade interleukin-1beta, but, similarly to many other MMP, could process a pro [tumor necrosis factor (TNF) alpha] fusion protein to release mature TNF. However, the latter was subsequently degraded into smaller fragments. These results demonstrate that, in addition to their ability to activate other MMP, such as progelatinase A/proMMP2 and procollagenase-3/proMMP13, MT-MMP degrade a number of extracellular matrix macromolecules. Their location at the surface of cells implies that they could play a significant role in the modulation of cell-matrix interactions.

Aggrecans↗
PubMed1997

Reproductive biology of seals.

The reproductive biology of seals is fascinating in many aspects. As in most mammals, the time of onset of puberty in seals is variable. Once sexually mature, most but not all seals are seasonally mono-oestrous, with highly synchronized breeding seasons. They have evolved as either terrestrial or aquatic copulators, although a few species mate in a variety of habitats. Their mating strategies are diverse, ranging from serial monogamy to extreme polygyny. Gestation in seals is characterized by an embryonic diapause, which is obligate in most species. Reactivation of the blastocyst is followed by a placental gestation. All species of seal require a terrestrial (including ice floes) habitat for parturition. Lactation differs between the two seal families: phocid seals have an intense period of maternal investment, during which the mothers fast; otariid seals have a prolonged lactation during which intense bouts of suckling are interspersed by days of separation from their pups while the mother forages at sea. Although the anatomy and functional morphology of seals has been well described, less is known of the endocrinology of reproduction. This is due mainly to the logistical difficulties that researchers experience in collecting serial samples from a species that is relatively difficult to handle. This article reviews the basic anatomy and physiology, and our current understanding of the comparative aspects of reproduction in seals. Reproductive behaviours as well as the influences of environmental factors, such as photoperiod, nutrition and xenobiotics, are also discussed.

Animals↗
PubMed1995

Erotic transference in the male adolescent-female analyst dyad.

Erotic transference involving female analysts and adult male patients has received increased attention in the past ten years. Absent from the literature, however, are any clinical reports concerning erotic transferences of adolescent male patients with female therapists. This paper presents a fragment of a treatment involving an adolescent male patient who developed an erotic transference. The vicissitudes of the transference, as well as his relationship to his mother and father, are discussed from the perspective of developmental conflicts and tasks of adolescence. The countertransference dimensions of this particular gender constellation are also examined from the standpoint of intrapsychic and cultural factors.

Adolescent↗
PubMed1995

The N-oxidation of trimethylamine in a Jordanian population.

The ability to oxidise trimethylamine (TMA) to trimethylamine N-oxide (TMAO) is distributed polymorphically within a British white population with the majority of individuals excreting greater than 90% of total urinary TMA as TMAO. The opposite extreme is characterised by a rare inborn error of TMA N-oxidation known as the fish-odour syndrome. However there is a lack of information regarding inter-individual variability in the N-oxidation of TMA in other ethnic groups. In this study the urinary excretion of TMA and TMAO was determined over a period of 24 h in 82 Jordanian subjects. A frequency distribution histogram of % of total urinary TMA excreted as TMAO revealed that the majority of subjects excreted greater than 80% of the total urinary TMA as TMAO, however eight subjects (9.7%) excreted less than 80% of the total TMA as TMAO. In a previous study of 169 white British subjects only one (0.6%) excreted less than 80% of the total TMA as TMAO. The results suggest that the prevalence of compromised ability to N-oxidise TMA may be higher in a Jordanian population than in a British population.

Adult↗
PubMed1995

Feasibility and acceptability of a proposed infant feeding intervention trial for the prevention of type I diabetes.

OBJECTIVE: To determine the feasibility of a randomized double-blind controlled trial of an infant formula without intact cow's-milk protein for preventing type I diabetes in high-risk children. RESEARCH DESIGN AND METHODS: We surveyed 83 people who either were parents of a child with type I diabetes or were pregnant women with type I diabetes in the ambulatory diabetes and obstetrics clinics in a university hospital. After a written and verbal description of the cow's milk-diabetes hypothesis, participants were asked to sign a sham consent form. A questionnaire designed to explore factors affecting their decision to either sign or not sign the consent form, as well as infant-feeding patterns, was subsequently administered. RESULTS: Overall, 69.9% (95% confidence interval, 60.0-79.8%) consented to participation in the proposed randomized trial. The decision to consent was not affected by the degree of belief in the cow's milk-diabetes hypothesis, the child's risk of diabetes, the respondent's demographic data, or infant feeding habits. CONCLUSIONS: A randomized feeding intervention study is an acceptable and feasible way to determine whether avoidance of cow's-milk protein during the first 6 months of life prevents type I diabetes in North American children.

Animals↗
PubMed1995

Trace elements in nutrition for premature infants.

Ten trace elements that are nutritionally essential include: zinc, copper, selenium, chromium, manganese, molybdenum, cobalt, fluoride, iodine, and iron. This article briefly reviews the biochemistry of these trace elements, describes clinical deficiency states, and provides a rationale for recommended enteral and parenteral intakes for preterm infants.

Copper↗
PubMed1994

Identification of futility in intensive care.

Rising costs of intensive care and the ability to prolong the life of critically ill patients creates a need to recognise early those patients who will die despite treatment. We used changes in a modified APACHE II score (organ failure score) to make daily predictions of individual outcome in 3600 patients. 137 patients were predicted to die and of these, 131 (95.6%) died within 90 days of discharge from hospital (sensitivity 23.4%, specificity 99.8%); a false-positive diagnosis rate of 4.4%. 2 of the 6 survivors have subsequently died but 4 are alive with good quality of life. Patients predicted to die stayed 1492 days in intensive care and incurred 16.7% of total intensive care expenditure and 46.4% of the cost of all patients that died. Median survival after a prediction to die was 2 days, accounting for 62% of intensive care patient days in this patient group, giving an effective intensive care cost per survivor of UK 129,651 pounds. If used prospectively, this algorithm has the potential to indicate the futility of continued intensive care but at the cost of 1 in 20 patients who would survive if intensive care were continued.

APACHE↗
PubMed1994

Reproductive morphology and status of female Hawaiian monk seals (Monachus schauinslandi) fatally injured by adult male seals.

Female Hawaiian monk seals at Laysan Island in the Northwestern Hawaiian Islands seasonally risk aggressive mating attempts by groups of adult male monk seals. These attacks, which also target immature female and male seals at a lower frequency, result in injuries that are often fatal and are termed mobbings. This study was undertaken to assess the reproductive status of nine female seals that died after mobbing attacks and to obtain basic morphological data of reproductive tracts from ten females. Reproductive morphology of the seals indicated that the lengths of the uterine body and both uterine horns were significantly shorter in nulliparous than in parous seals. Seven of the nine seals were periovulatory, on the basis of gross morphology of the ovaries at death. The ovaries of the other two seals possessed immature follicles. Histological studies of the vagina and uterus confirmed the reproductive status of the seals. When the reproductive status at the time of first injury was estimated, all seals were in the follicular phase of the oestrous cycle. At least four of these seals were estimated to be in oestrus at the time of their first injury, and seven of the seals sustained at least one injury during the estimated period of oestrus (2-6 days). These results support the hypothesis that most adult female Hawaiian monk seals that die following an attack by male monk seals are periovulatory, and that the majority of the attacks occur during oestrus.

Animals↗
PubMed1994

Applications of statistical process control in health care.

Statistical process control (SPC), most commonly applied in manufacturing industries, will be demonstrated to have applicability in health care. In particular, the use of a patient classification system such as DRGs that identify hospital end products can assist in the use of SPC and process improvement. An overview of SPC is given, followed by two case studies presented to demonstrate the use of SPC. Lastly, some ideas on teaching SPC to health care workers are outlined.

Australia↗