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Biomedical subjects

M Andrews

Publications and source records attributed to M Andrews.

107 records · Page 6Linked to original sources
PubMedDate not supplied

Dextrorphan effects on cocaine and brainstem perturbation.

UNLABELLED: Dextrorphan is a noncompetitive blocker of N-methyl-D-aspartate (NMDA) receptors. Since NMDA blockers are known to reduce the locomotor stimulatory and toxic effects of cocaine, it was speculated that dextrorphan would attenuate cocaine-induced behavioral excitatory motor activity associated with and without mechanical perturbation of the brainstem. TECHNIQUE: Motor activity was recorded following dextrorphan and/or cocaine challenge in 25 SHR rats. Ten were naive subjects. Mini-osmotic pumps delivering cocaine (2.5 mg/0.49 ul/hr) were placed in 15 subjects, and infusion was halted after the third infusion day. On the fifth day either a dextrorphan (25 mg/kg, subcutaneous) or a dextrorphan and cocaine (40 mg/kg, intraperitoneal) challenge was done. Ten rats had bipolar electrode implants in the bilateral brainstem. Five were treated with DC current lesions in each of 12 days over a 3-week period. The effects of brainstem lesions on escape behavior were also evaluated in those five subjects. RESULTS: In the naive subjects, dextrorphan reduced motor activity (P = .0001), whereas combined cocaine and dextrorphan increased motor activity (P = 0.04). In lesioned subjects, dextrorphan decreased motor activity (P = 0.0001). In electrode implant subjects, combined dextrorphan and cocaine challenge decreased the motor activity (P = 0.04). Hyperactivity in the electrode implant group was greater than in the lesioned subjects. Midbrain electrolytic lesions attenuated escape behavior. A variety of behaviors were produced by brainstem lesions. CONCLUSIONS: Dextrorphan and brainstem lesions reduced motor hyperactivity and escape behavior. In electrode implant subjects dextrorphan counteracted the expected cocaine excitatory motor effects. Dextrorphan did not activate nor facilitate seizures.

Animals↗
PubMedDate not supplied

Cocaine-induced brainstem seizures and behavior.

A variety of abnormal sensory/motor behaviors associated with electrical discharges recorded from the bilateral brainstem were induced in adult WKY rats by mechanical (electrode implants) and DC electrical current stimulations and by acute and chronic administration of cocaine. The electrode implant implicated one side or the other of the reticular system of the brainstem but subjects were not incapacitated by the stimulations. Cocaine (40 mg/kg) was injected subcutaneously for an acute experiment and subsequent 20 mg/kg doses twice daily for 3 days in a chronic study. Cocaine generated more abnormal behaviors in the brainstem perturbation group, especially the electrically perturbated subjects. The abnormal behaviors were yawning, retrocollis, hyperactivity, hypersensitivity, "beating drum" behavior, squealing, head bobbing, circling, sniffing, abnormal posturing, and facial twitching. Shifts in the power frequency spectra of the discharge patterns were noted between quiet and pacing behavioral states. Hypersensitivity to various auditory, tactile, and visual stimulation was present and shifts in the brainstem ambient power spectral frequency occurred in response to tactile stimulation. These findings suggest that the brainstem generates and propagates pathological discharges that can be elicited by mechanical and DC electrical perturbation. Cocaine was found to activate the discharge system and thus induce abnormal behaviors that are generated at the discharge site and at distant sites to which the discharge propagates. Cognitive functions may also be involved since dopaminergic and serotonergic cellular elements at the brainstem level are also implicated.

Animals↗
PubMedDate not supplied

Effect of verbal self-disclosure on natural killer cell activity: moderating influence of cynical hostility.

One objective of the present research was to examine the immunological effects of self-disclosing personal information regarding a traumatic or stressful experience. A second objective was to examine the hypothesis that the effect of self-disclosure on immune function is moderated by individual differences in cynical hostility. Forty-three male college undergraduates, classified as high or low on the Cook-Medley Hostility scale were randomly assigned to either a verbal self-disclosure or a nondisclosure discussion condition. Task-induced change in natural killer (NK) cell activity (i.e., cytotoxicity) served as the dependent variable. As predicted, a significant interaction between discussion condition and hostility was obtained. Among subjects in the self-disclosure condition, high hostility subjects exhibited a significantly greater increase in NK cell cytotoxicity than low hostility subjects. The effect of self-disclosure on NK cell activity is moderated by an individual's level of cynical hostility. The greater short term enhancement in NK cell activity observed for hostile persons is a likely correlate of a more pronounced acute arousal response elicited by the self-disclosure task.

Anxiety Disorders↗
PubMedDate not supplied

Anterior cruciate ligament allograft reconstruction in the skeletally immature athlete.

The purpose of this study was to evaluate anterior cruciate ligament allograft reconstruction in skeletally immature athletes. Eight patients (mean age, 13 years, 6 months; range, 10 to 15 years) with radiographic documentation of open growth plates had anterior cruciate ligament repair and reconstruction with fascia lata or Achilles tendon allograft tissue. A 7-mm graft was centrally placed across the tibial physes and in an over-the-top position on the femur. All patients returned for followup a mean of 58 months (range, 22 to 94) postoperatively. All had an immediate knee motion and rehabilitation exercise program. The results were rated on a comprehensive rating system that assessed 20 variables. At followup, all patients showed closure of the growth plates. The difference in lower limb length, measured on scanograms, was not clinically significant. On KT-1000 arthrometer testing, 5 patients had less than 3 mm of increased anterior-posterior displacement (normal knee minus reconstructed knee) and 3 patients had between 3 and 5 mm. The final overall ratings were 6 excellent, 1 good, and 1 fair. The procedure is infrequently used, but appears to have merit in select, skeletally immature athletes who desire not to modify athletic activity or when associated meniscal repairs warrant consideration for reconstruction.

Achilles Tendon↗
PubMedDate not supplied

Knee hyperextension gait abnormalities in unstable knees. Recognition and preoperative gait retraining.

Five patients with symptomatic knee hyperextension thrusting patterns due to posterolateral ligament complex injury underwent gait analysis before and after a gait retraining program. Patients were trained to avoid knee hyperextension by 1) walking with their knees slightly flexed throughout stance, 2) maintaining ankle dorsiflexion in early stance, and 3) maintaining an erect trunk-hip attitude during stance. Kinematic and kinetic measurements were obtained using automated gait analysis. Four of the five patients significantly reduced hyperextension at the knee and abnormal motion patterns at the hip and ankle. Patients showed increases in knee flexion throughout stance conversions of knee flexion-extension moments to more normal biphasic patterns with a 79% decrease in extension moments at terminal extension, and a 22% decrease in knee adduction moments. Posttraining values also showed a 30% decrease in the calculated medial tibiofemoral loads (P < 0.05). At the hip, there were significant decreases in abduction and adduction moments (36% and 18%, respectively, P < 0.01). Ankle plantar flexion motion decreased significantly by 42% (P < 0.01). Gait retraining can alter the biomechanics of hip, knee, and ankle function to approximately normal levels, and therefore is recommended before ligament reconstruction because abnormal knee motions, if resumed postoperatively, can stretch soft tissue reconstructions.

Adult↗
PubMedDate not supplied

A rigorous comparison between the sexes of results and complications after anterior cruciate ligament reconstruction.

Although there is a higher relative incidence of anterior cruciate ligament injuries in female than in comparable male athletes according to the literature, the majority of populations studied after reconstruction are male-dominated. We wished to determine whether a selection bias for reconstruction based on sex is warranted according to complications and outcome. Ninety-four patients (47 of each sex) were matched for chronicity of injury, age, preoperative sports activity levels, articular cartilage condition, and months of followup. All had patellar tendon autogenous reconstruction and a similar program of immediate knee motion and early return to function. The results were rated with the Cincinnati Knee Rating System. At a mean of 26 months postoperatively, there were no significant differences for complications or outcome between men and women. Women required an average of six more rehabilitation visits than men; however, none required additional surgery for knee motion complications and the rate of patellofemoral crepitus conversion was only 7%, lower than that found for men (15%). The overall failure rate was low, only 6% for women and 4% for men. We concluded that the functional rehabilitation program was effective, postoperative complications were few, and no scientific basis exists to use sex alone as a selection criteria for anterior cruciate ligament reconstruction.

Adolescent↗
PubMedDate not supplied

Comfort and incidence of abnormal serum sodium, BUN, creatinine and osmolality in dehydration of terminal illness.

This prospective clinical study was undertaken to evaluate the effect of spontaneous food/fluid intake on serum sodium and comfort levels in a population of terminal patients (n = 31) receiving clysis or intravenous hydration. The median and mode of serum sodium were within normal limits and 56 percent of the patients were eunatremic. There was no statistically significant difference in comfort scores between predehydration and dehydration phases, and 85 percent had an optimal comfort score. A statistically significant difference was found (p < 0.5) between mean daily comfort scores of those with normal sodium versus those with abnormal sodium; those with hypernatremia were lower but still in the top third comfort levels. Because the sodium was tested using a Chem7, we also were able to calculate the BUN, creatinine, and osmolality. These are presented and compared to other study results. The findings of this study reinforce the belief that fluid depletion in dying patients results in relatively benign symptoms, that serum sodium levels are not always altered with limited intake and that comfort levels can be maintained when the serum sodium is abnormal.

Adult↗
PubMedDate not supplied

Importance of nursing leadership in implementing change.

Change is an aspect of all our lives and nurses are no exception. This article explores the concept of change in nursing and highlights the importance of effective leadership in implementing change. It outlines several change strategies and makes suggestions with regard to choosing an effective approach.

Humans↗
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Using reflection to develop clinical expertise.

Reflection is becoming widely recognized as an effective means by which nurses can develop their practice and is a prominent feature of both pre- and postregistration education programmes. More specifically, the UKCC directs that all nurses are required to keep a personal, professional profile, which means that they are obliged to engage in reflective activities. In order to develop practice, nurses must reflect on what they do and what they would want to do better. Reflection is a purposeful activity which is more than just a recall of events. Implicit within reflective activity is a need on the relector's part to change behaviour. The following article explores the concepts of expertise and reflection and suggests how one may relate to the other. Its purpose is to heighten awareness of the use of reflection for profile development and ultimately as a means of developing nursing practice.

Clinical Competence↗
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Reflection: does it enhance professional nursing practice?

It is generally accepted that nurses who engage in reflective activity do so to develop their practice. However, there is little empirical evidence to suggest that practice development or improved patient care occurs as a direct result of reflection. The UKCC, as part of its framework for postregistration education, expects all nurses to engage in some form of reflective activity and to provide written accounts within a personal professional profile. This article examines some of the assumptions surrounding the practice of reflection and asserts that, in the main, nurses do not readily engage in reflection in a purposeful way.

Education, Nursing, Continuing↗
PubMedDate not supplied

Family support and child adjustment in single-parent families.

The complex phenomenon of single parenthood is explored within Roy's (Roy & Roberts, 1981) adaptation framework. Correlation analysis of a large family data set supported the literature and the conceptual framework. Findings suggested that single parents experienced a characteristic set of stressors distinguishing them from two-parent families. The mere availability of help with parenting seemed less important in fostering the children's positive adaptation than the quality of the relationship among the adults involved with the children. Practitioners are advised to address family support and the ability to cope with environmental factors when developing a treatment plan.

Adaptation, Psychological↗
PubMedDate not supplied

Recurrent infection and catheter loss in patients on continuous ambulatory peritoneal dialysis.

OBJECTIVE: To elucidate the factors leading to catheter loss from recurrent infection in patients on continuous ambulatory peritoneal dialysis (CAPD). DESIGN: All catheters removed from patients were prospectively examined for infection. SETTING: CAPD unit in large tertiary-care general hospital. PATIENTS: Sixty-five consecutive patients undergoing catheter removal for whatever cause; 20 catheters rejected because of desiccation or contamination in transit. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Micro-organisms linked to catheter removal; their locations on removed catheters. RESULTS: Of 45 catheters removed between January 1994 and August 1995, 26 were infected: 13/26 infections were caused by Staphylococcus aureus and 7/26 by Pseudomonas aeruginosa. In only one case was S. epidermidis associated with catheter removal. The most striking finding was that the inner cuff harbored large numbers of the infecting organisms, even when antibiotics had eradicated them from the peritoneal cavity and exit site, where present, and the catheter lumen. CONCLUSION: The importance of S. aureus and Ps. aeruginosa rather than S. epidermidis in catheter loss due to relapsing infection is confirmed. Persistence of the causative organisms in the inner cuff is a likely explanation for relapse after treatment, and might be due to the predominantly intraperitoneal administration of antibiotics. A clinical trial of the effect on catheter retention of empirical use of systemic or oral agents that give high tissue levels and are active against intracellular micro-organisms, along with recommended intraperitoneal regimens, is indicated.

Administration, Oral↗
PubMedDate not supplied

Intraperitoneal insulin--a dose response curve.

To determine a dose response curve for intraperitoneal (i.p.) insulin using Sprague-Dawley rats, human insulin was administered i.p. in 1.5% glucose dialysate at the following doses: 10 U (2.19 U/100 g body wt); 5U (1.23 U/100 g body wt); 2 U (0.49 U/100 g body wt); 1 U (0.27 U/100 g body wt). A bolus injection of glucose was given to elevate blood sugar, followed by infusion of D20%. Blood sugar was maintained at 250 mg/dl by checking at 10 minute intervals and adjusting the IV infusion. Dialysate with regular insulin was instilled after blood sugar was constant for 20 minutes. The end-point was the amount of glucose to maintain a blood sugar of 250 mg/dl after instillation of dialysate and regular insulin. Mean blood sugars were similar within and between each dose group. The effect of regular insulin was noted within 10 minutes. The amount of glucose used with the IV dose differed from all other (p less than 0.05). The amount used by the 5 and 10 U doses of i.p. insulin were similar. Increasing amounts of glucose are required to maintain the blood sugar at increasing doses of intraperitoneal regular insulin up to 5 U. Thus, there appears to be a dose response curve for i.p. insulin.

Animals↗