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Biomedical subjects

D Sadler

Publications and source records attributed to D Sadler.

At least 19 recordsLinked to original sources
PubMed2005

The Tidal Model as experienced by patients and nurses in a regional forensic unit.

The Tidal Model has been implemented in Rangipapa, a regional secure mental health forensic unit in New Zealand. A phenomenological study was undertaken to obtain reflective description of the nursing care experience from the perspective's of four Registered Nurses and four Special Patients. Five major themes were identified that appeared to capture the experiences of the participants. The themes show changes to the unit's unique culture and values following implementation of the model. These changes engendered a sense of hope, where nurses felt they were making a difference and patients were able to communicate in their own words their feelings of hope and optimism. Levelling was experienced as an effect emerging from individual and group processes whereby a shift in power enhanced a sense of self and connectedness in their relationships. These interpersonal transactions were noted by the special patients as being positive for their recovery. This enabled effective nurse-patient collaboration expressed simply as working together. The participants reported a feeling of humanity, so that there was a human face to a potentially objectifying forensic setting. Implications arising from this study are that the use of the model enables a synergistic interpersonal process wherein nurses are professionally satisfied and patients are validated in their experience supporting their recovery.

Attitude of Health Personnel↗
PubMed2001

Screening for cerebellopontine angle tumours: conventional MRI vs T2 fast spin echo MRI.

BACKGROUND: Unilateral audiovestibular symptoms are commonly seen in clinical practice and are rarely caused by retrocochlear pathology. However, clinicians are often required to rule out potentially serious causes of these unilateral symptoms. Gadolinium enhanced magnetic resonance imaging (GdMRI) is the most accurate test for detecting small cerebellopontine angle lesions and also screens the adjacent CNS structures. Its main disadvantage is the cost of the procedure. METHODS: We studied 100 consecutive patients with both GdMRI and a newer MRI screening study utilizing unenhanced T2-weighted fast spin echo (fse) MRI. Acquired images were randomly assessed by a panel of three neuro-radiologists. RESULTS: We found that the screening (fse) MRI was as sensitive and specific when detecting cerebellopontine angle tumors. CONCLUSIONS: We conclude that T2-weighted fse MRI is a safe and cost-effective alternative to GdMRI and offers better diagnostic utility when compared to auditory brain stem response (ABR) and CT scans.

Brain Stem↗
PubMed2001

Radiologic placement of central venous catheters: rates of success and immediate complications in 3412 cases.

OBJECTIVE: To determine the success and immediate complication rates associated with 3412 central venous catheter placements performed in an interventional radiology suite. METHODS: Success and immediate complication rates were prospectively recorded for 3412 consecutive patients who had central venous catheters radiologically placed at a tertiary care centre between July 1993 and October 2000. The indication for placement and the insertion site were also recorded. RESULTS: The most common indication for both short- and long-term venous access was hemodialysis, and the right internal jugular vein was the most common site for catheter insertion. Placement was successful for 98.8% of tunnelled lines and 99.3% of temporary catheters. The rate for immediate complications (including pneumothorax, air emboli, bleeding and arterial puncture) for tunnelled catheter placements was 3.8% and for temporary catheter placements was 1.6%; no major complications were documented. CONCLUSION: Our results lend further evidence to the claim that the success and immediate complication rates of radiologically placed central venous catheters compare favourably with blind placement and surgical placement of central venous catheters.

Adolescent↗
PubMed2000

Non-penetrating chest blows and sudden death in the young.

Sudden death in the young after low energy anterior chest wall impact is an under-recognised phenomenon in this country. Review of the literature yields several American references to commotio cordis, mainly in the context of sporting events. Two cases are reported of sudden death in young men as a result of blunt impact anterior chest wall trauma. It is suggested that these cases draw attention to a lethal condition of which many practitioners are unaware.

Adolescent↗
PubMed2000

Dietary fatty acids influence the appearance of tumour necrosis factor-alpha receptors on adipocytes following an immune challenge.

Rats were fed from weaning on chow supplemented with suet or sunflower oil (10 % (w/w) each). The appearance of receptors for tumour necrosis factor-alpha on perinodal adipocytes from the popliteal depot following a subcutaneous injection of bacterial lipopolysaccharide was examined. In rats fed on sunflower oil-supplemented chow receptors appeared at a time similar to that described in rats fed unsupplemented chow, but in rats fed on chow supplemented with suet receptor appearance was significantly delayed. The popliteal adipocytes were found to contain different proportions of fatty acids as assessed by GLC. These preliminary results suggest that the fatty acid component of the diet can, by influencing the triacylglycerol-fatty acids within adipocytes, directly alter the time course of an early inflammatory immune response.

Adipocytes↗
PubMed1997

Reporting animal use in scientific papers.

This paper reports the results of an examination of the 'methods' sections of a range of experimental research papers in biomedical science, focusing on the descriptions of animal use and housing. Detailed descriptions in the methods should enable replication, and also enable readers to judge scientific quality. Relatively few papers sampled gave adequate descriptions of housing conditions and many failed to give details of physiologically relevant variables such as weight of animals. Thirty per cent of papers omitted the number of animals used, and the deaths of animals (whether as part of the protocol, or accidental death) were not always recorded. Adequate reporting of the conditions of animal maintenance and use are important, both in relation to the quality of the science produced, and also because of public concerns about the ethics of animal experiments.

Animal Husbandry↗
PubMed1992

The effects of exercise and feeding on the activity of lipoprotein lipase in nine different adipose depots of guinea pigs.

1. The activity of lipoprotein lipase (LPL) was measured in whole adipose tissue from 9 identified adipose depots of sedentary, fasting adult guinea pigs and following 30 min of exercise or voluntary ingestion of chow, and in adipocyte and stromal-vascular fractions from exercised specimens. 2. In sedentary, fasting specimens, LPL activity was up to 4 times higher in the small intermuscular depots than in the perirenal and epididymal depot (Table 1). 3. LPL activity increased significantly after feeding only in the large superficial depot, groin, and in the perirenal depot. LPL activity decreased after exercise only in the 2 intermuscular depots and in small anterior superficial depots. These effects of exercise were consistently greater in males than in females (Table 3). 4. Following exercise, there was up to twice as much LPL in the adipocytes as in the stromal-vascular fraction of the intermuscular depots, about 50% more in adipocytes from the minor superficial depots and about equal quantities in the 2 fractions of the intra-abdominal and groin depots (Table 2). 5. The data demonstrate the physiological inhomogeneity of both superficial and internal adipose depots, and are consistent with the hypothesis that LPL originating from adipose tissue may enter the circulation.

Adipose Tissue↗
PubMed1991

Conventional versus thrombolytic therapy in spontaneous (effort) axillary-subclavian vein thrombosis.

Effort axillary-subclavian vein thrombosis in young patients has produced long-term disability because of the failure of the thrombosed vein to recanalize. Ten consecutive patients treated in our institution were analyzed. All patients were diagnosed by venography. Four patients received thrombolytic therapy. Three of these had complete resolution and one had partial resolution of the symptoms and thrombus, that was confirmed by venography and duplex imaging. The remaining six patients were treated with conventional anticoagulant therapy. Three of these patients had no resolution, one had complete resolution of both symptoms and thrombus, and two had only partial resolution of symptoms but no resolution of thrombus. Thrombolytic therapy appears to be superior to anticoagulation in the dissolution of symptoms in effort vein thrombosis and should be considered in its management if the diagnosis is made early.

Adult↗
PubMed1991

Maternal discrimination and the development of sex differences in exploratory behaviour in infant spiny mice (Acomys cahirinus).

The present paper reports sex differences in exploratory behaviour by infant Spiny Mice, Acomys cahirinus, that may, in part, be related to differences in maternal behaviour towards pups; like some other rodents, mother Acomys differentiate behaviourally between male and female pups. In Experiment 1 infant Acomys were allowed to explore a novel arena. This experiment showed that even by Day 3 (the day of birth = Day 1) female Acomys explored a novel environment more than males; they entered the arena sooner than males and spent more time in contact with a novel object. Experiment 2 showed that infant females were more active than males when observed in the home cage in the presence of their parents and made more approaches to the mother. Mothers, on the other hand, directed more licking behaviour towards males. Experiment 3 focused on the exploratory behaviour of individual pups in the presence of the mother. Given access to a large, complex arena, female pups explored more than males. The results also showed that mothers direct more of their social interactions towards sons than daughters, particularly when pups are about a week old. Some mothers appear to "direct" the movement of their offspring, by blocking their forward movement; this was done more often to male than to female pups. The data suggest that the previously observed changes in exploratory behaviour at this time, and the emergence of sex differences in exploration, may in part depend upon the mothers' reactions to pups by sex.

Animals↗
PubMed1990

Role of thrombolytic therapy in axillary-subclavian vein thrombosis.

Axillary-subclavian vein thrombosis in young patients has produced long-term disability because of failure of the thrombosed vein to recanalize. In a review of 10 patients with axillary-subclavian vein thrombosis treated in our institution, four were effort vein thrombosis. All patients were diagnosed by venography. One patient received urokinase with complete resolution of symptoms and complete dissolution of the clot after two days of initial therapy, which was confirmed by venography and duplex imaging. Another patient received streptokinase with partial resolution of symptoms and dissolution of the clot, which was confirmed by venography. The other two patients were treated with conventional anticoagulant therapy with partial resolution of symptoms and no dissolution of the clot. Thrombolytic therapy appears to be superior to anticoagulation in dissolution of symptoms in effort vein thrombosis and should be considered in its management if the diagnosis is made early.

Adult↗
PubMed1988

Effects of modulating neonatal progestins and androgens on the development of play and other social behavior in the rat.

Rough-and-tumble play is sexually dimorphic in many species of mammals. Effects of androgen exposure on this behavior have been well documented, although the possible role of other hormones is less well known. This paper reports experiments in a series designed to investigate effects of neonatal exposure to progestins on the development of juvenile play behavior in rats. Specifically, the effects of altering levels of progestins and androgens in combination on the subsequent development of play behavior was studied, in order to investigate further the mechanism of progestogenic effects. We have previously [L. I. A. Birke and D. Sadler (1984). Physiol. Behav. 33, 217-219] reported an apparently anomalous effect of lowering endogenous progesterone using the antiserum given postnatally; this was predicted to raise levels of juvenile play. The prediction was, however, supported only for males; treated females showed lower levels of play than controls. The present study was designed to investigate these effects further, and to test hypotheses about the mode of action of neonatal progestins. Using various combinations of neonatal progestins (progesterone or medroxy-progesterone acetate, MPA), and testosterone or the antiserum to testosterone, we analyzed the amounts of play and other social behavior shown by juvenile rats. The data support a hypothesis that the previously reported effects of progestin exposure on play result from weakly androgenic actions of the progestins, which presumably compete with other androgens in males. The cellular mechanisms involved are, however, unknown.

Agonistic Behavior↗
PubMed1987

Differences in maternal behavior of rats and the sociosexual development of the offspring.

This paper describes experiments designed to investigate long-term behavioral consequences for offspring of changes in maternal behavior directed toward them as pups. Specifically, the hypothesis was considered that experimentally induced alterations in maternal behavior would result in general and wide-ranging effects on offspring development, including effects on later social and sexual behavior. The first experiment looked at the effects of changing pup odors on maternal responsiveness toward the pups, and showed that the application of perfume, particularly to the anogenital region, resulted in significant lowering of maternal anogenital licking of pups. Non-pup-directed behavior did not differ between groups. The behavior of those pups that had thus differed in infant experience was then followed in three subsequent experiments. In Experiment 2, social behavior during the juvenile period was investigated, focusing particularly on the expression of social play. The most noticeable difference to emerge in this experiment was that male pups that had been anogenitally perfumed as infants showed much higher levels of social play than male or female pups from other treatment groups. The last two experiments considered adult behavior. Experiment 3 showed that there are no lasting effects of the neonatal treatment on the attractiveness an animal has for its conspecifics. In the final experiment, "masculine" sexual behavior of males (mounts with intromission), and "feminine" sexual behavior of females (i.e., lordosis and proceptive behavior) were investigated. This confirmed previous reports by Moore (1984) (Moore, C. L. (1984). Maternal contributions to the development of masculine sexual behavior in laboratory rats. Dev. Psychobiol., 17:347-363) that those male pups that had received lower rates of anogenital licking as pups showed longer intermount intervals, when tested as adults. The results are discussed in relation to the development of sexually differentiated behavior.

Animals↗
PubMed1987

Effects of odor familiarity on the development of systematic exploration in the spiny mouse, Acomys cahirinus.

Developmental changes in patterns of exploration by infant spiny mice, Acomys cahirinus are described. These were investigated using an unbaited radial maze and under three odor conditions; that is, animals were tested in the presence of either familiar (own) odors, unfamiliar conspecific odors, or no odors (washed floor). Two hypotheses were tested. The first was based on the results of a pilot study, and was that adult animals would explore the radial maze in a systematic and predictable fashion tending to move from one arm to the next sequentially. It was hypothesized that infants would adopt this sequential strategy only gradually, as they matured. The second hypothesis was that such patterns of exploration would depend upon the olfactory environment; the presence of familiar odors might facilitate systematic patterns of exploration in very young Acomys. The results showed that both adults and juveniles were less likely to move sequentially when tested with no conspecific odor present; sequential patterns of movement were most likely in the presence of unfamiliar odor, however. The only significant change with age in infants was found for animals tested with unfamiliar odors; these animals showed a dramatic increase in sequential behavior between 3 and 7 days of age. Two additional experiments are reported, which investigated the preferences of infant Acomys for unfamiliar conspecific odors, and it was found that very young (about 3 days) animals exhibit a preference for odors derived from unfamiliar conspecific litters, even when tested in the physical presence of their own parents. The results are discussed with reference to the use of olfactory information as directional cues for animals exploring the radial maze.

Age Factors↗
PubMed1987

The effects of exercise and dietary restriction on the activities of hexokinase and phosphofructokinase in superficial, intra-abdominal and intermuscular adipose tissue of guinea-pigs.

1. The activities per gram of adipose tissue of hexokinase and phosphofructokinase were higher in the centre two intermuscular adipose depots of guinea-pigs than in any of the seven superficial and intra-abdominal depots studied. 2. The capacity for glucose utilization was reduced following about 3 months of regular exercise in all adipose depots studied except in the popliteal depot. The proportion of lipid decreased, and that of protein increased, in this intermuscular depot following regular, strenuous exercise, but it did not enlarge disproportionately. 3. We suggest that certain intermuscular adipose depots may act as a local energy source for adjacent muscles. The anatomical relations of adipose tissue to muscle may be an integral part of its physiological function.

Abdomen↗
PubMed1986

Patterns of exploratory behavior in the spiny mouse, Acomys cahirinus.

The present paper reports an investigation of patterns of exploratory behavior shown by laboratory-bred Spiny Mice (Acomys cahirinus) when given access to a large, novel arena. The aim was to test hypotheses suggested by our previous work with this species. Previous experiments in which the exploratory behavior of Acomys was compared with that of Mus had suggested that each species had a characteristic pattern of emergence and exploration. The present experiment addressed the question of whether the exploratory patterns of Acomys could be predicted from patterns of emergence as suggested by earlier experiments. Data are presented which indicate that the exploratory behavior of Acomys in a large, novel arena is reasonably predictable. The data presented include measures of the animal's responses to different stimuli within the novel environment, including novel, conspicuous objects, food sources, and the holding cage to which the animal could return. In addition, the patterns of movement through different areas of the environment were recorded in relation to the behavior of the animal when it was first given access to the arena. The data indicate that there are two types of strategy, or patterns, by which Acomys begin to explore a novel environment. The first type consists of a delayed emergence into the arena, followed by brief excursions into the area immediately adjacent to the holding cage, interspersed with longer periods of returns to the holding cage. The second type involves immediate emergence, followed by rapid "dashes" around the periphery of the arena. Which of the two strategies is adopted appears to depend upon the animal's behavior at the time of initial access. Two subsequent experiments considered these strategies further. Experiment 2 indicated that Type I was more characteristic of males and Type II more characteristic of females, although there were no differences related to the female estrous cycle. In Experiment 3, the patterns of exploration over four consecutive tests were investigated. It was found that the strategy adopted by an individual is likely to be consistent across tests.

Animals↗