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Biomedical subjects

D Blackman

Publications and source records attributed to D Blackman.

17 recordsLinked to original sources
PubMed1996

Challenging behaviour: the effectiveness of specialist support teams.

Two specialist community services for people with learning disabilities and challenging behaviour were evaluated over approximately 3 years. Intervention effectiveness was assessed with respect to changes in subjects' skills, challenging behaviours, mental health and quality of life, and to changes in staff morale. Subjects assessed as having challenging behaviour but not referred for specialist input were also studied. Comparison of changes in referred and non-referred samples over time showed minor differences only, indicating little intervention effect and demonstrating stability in the comparison sample. Analysis of the two services separately yielded different results. Positive client change was evident with respect to one service, whilst little change was noted with respect to the other. There was little evidence to suggest that either service had any effect on staff morale. Differences between the two services in terms of structure, staffing characteristics and operational policies are discussed as possible factors in the differential results obtained. A major issue raised by the study concerns the quality of settings from which the subjects were referred for specialist support. This is discussed as a factor which may limit the effectiveness of specialist input.

Adolescent↗
PubMed1995

People with learning disabilities and challenging behaviour: the characteristics of those referred and not referred to specialist teams.

The characteristics of two samples of people with learning disabilities and severely challenging behaviour were examined. The experimental sample comprised subjects who had been referred to two specialist challenging behaviour services in separate counties. The comparison sample comprised subjects from the same counties who were not referred or accepted for specialist intervention. No significant differences were found between the samples in terms of age, gender, social impairment, dependency characteristics, ability levels and mental health. Significant differences between them were found in the nature and severity of aberrant behaviour presented, as assessed by their carers. The implications of these findings are discussed with regard to how the term 'severely challenging behaviour' is defined in practice.

Activities of Daily Living↗
PubMed1993

Common phosphatidylinositol 4,5-bisphosphate pools are involved in carbachol and serotonin activation of tracheal smooth muscle.

We examined the rate and extent of labeling of total cellular phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol (PI) in canine tracheal smooth muscle in response to maximum levels of two different contractile agonists, carbachol (5.5 microM) and serotonin (5-hydroxytryptamine, 5-HT) (47 microM) and when a second agonist was given during a maximal contraction evoked by the first agonist. Unstimulated tracheal smooth muscle strips were incubated with [3H]-myo-inositol (MI) to label tissue MI without much labeling of inositol phospholipids. With carbachol, there was a 20-fold increase in the [3H]-MI incorporation rate into inositol phospholipids, decreases in PI and PIP2 contents, and increases in phosphatidic acid and diacylglycerol contents. PI and PIP2 specific radioactivities reached plateaus, 0.90 +/- 0.03 and 0.80 +/- 0.04, respectively, compared with [3H]-MI specific radioactivity. 5-HT at 47 microM evoked smaller changes including force development, [3H]-MI incorporation rate and lipid mass changes. However, the plateau of PI and PIP2 labeling reached levels similar to that determined during carbachol-evoked force, 0.90 +/- 0.06 and 0.82 +/- 0.04, respectively. Carbachol (55 microM) addition after incubation with 5-HT did not significantly alter the plateau levels of the specific radioactivities of PI or PIP2, although force and lipid mass changes were significantly changed. We conclude that 5-HT and muscarinic receptor coupling mechanisms utilize the same pool of PIP2 as a substrate for phospholipase C activation and the same PI pool for conversion to PIP and PIP2.

Animals↗
PubMed1992

Efficacy of nursing home preadmission screening.

This study evaluates the efficacy of four state nursing home preadmission screening instruments. Using data from three community-based services demonstration experiments, the screens were compared on measures of sensitivity, specificity, and proportions of false negatives and false positives. Results indicate that the more restrictive screens tended to have lower sensitivity but higher specificity, and to generate a higher proportion of false negative decisions than the more liberal screens. Overall rates of correct prediction were higher for the more restrictive screens. Results highlight differences in eligibility restrictiveness across states as well as possible tradeoffs of cost containment and access in designing a preadmission screen.

Aged↗
PubMed1968

Response rate, reinforcement frequency, and conditioned suppression.

In the first of two experiments, periods of noise were terminated with unavoidable shock to 36 rats. The rats' continuously reinforced responding was later completely suppressed during the noise when it was introduced without shock. The rats were then assigned to nine experimental groups. Each group was exposed to different paced variable-interval schedules of reinforcement, which independently controlled response rate and reinforcement frequency. Periods of the noise were periodically superimposed on these schedules, and loss of response suppression was studied. Differences between the groups were assessed statistically. The second experiment used a steady-state design. Six rats were exposed to paced schedules which generated two alternating response rates but gave constant reinforcement frequencies, and six rats to schedules which maintained the same response rates throughout, but in which the reinforcement frequency was alternately high and low. Response suppression was studied during a pre-shock stimulus superimposed on each rat's two behavioral baselines. Both experiments suggest that (1) conditioned suppression is affected by rate of operant responding, high rates being most suppressed, and (2) the frequency of reinforcements obtained also has an effect, most suppression occurring when frequency is low.

Animals↗
PubMed1968

Conditioned suppression or facilitation as a function of the behavioral baseline.

Rats were exposed to a multiple schedule of reinforcement. During one component, a bar-press was followed by reinforcement only if it occurred between 15 and 20 sec after the previous response. This differential-reinforcement-of-low-rate (DRL) schedule produced a typical slow rate of responding. During the other component, reinforcement followed the first response to be emitted during limited periods of time which occurred at fixed intervals. These fixed-interval schedules with a limited hold produced higher response rates, described as ;interval' or ;ratio-like' behavior. Responding during the DRL component increased in frequency during a tone which ended with an unavoidable shock of low intensity, but decreased during the tone when the shock intensity was raised. The ;interval' and ;ratio-like' responding decreased in frequency during the tone at all shock intensities. Initial acceleration of the DRL responding appeared to be due to adventitious punishment of collateral behavior which was observed between the bar-presses. The more severe conditioned suppression during the fixed-interval components might be the result of the lower probability of reinforcement after any single response.

Animals↗
PubMed1966

Some effects of methylphenidate on stimulus control of ratio avoidance behavior in the rat.

After exposure to an avoidance schedule which included a warning signal, a rat was placed on a multiple schedule in which the first component was the same as before, i.e., a single response reset the response-shock interval, delaying shock, and the second component differed only in that four bar-presses were required to postpone shock. A fixed ratio requirement of four responses (FR 4) generated behavior resembling a fixed ratio requirement of one response (FR 1) since responding was controlled by the warning signal but more shocks were received. At a dosage of 2 mg/kg, methylphenidate given intraperitoneally decreased shock frequency during FR 4 periods while FR 1 behavior was not affected; at 4 mg/kg, stimulus control of avoidance responding was impaired during both components. Results at 4 mg/kg were partially confirmed by two animals exposed to an FR 4 avoidance schedule which included a warning signal but with different parameters. Response distributions showed that methylphenidate increased response rates in the absence of the warning signal, i.e., stimulus control of ratio-avoidance behavior was impaired although the increased response rates reduced shock frequency. One hour later responses again occurred more frequently during the signal than in its absence but shocks were less frequent than during control (non-drug) periods.

Animals↗