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Biomedical subjects

B A Campbell

Publications and source records attributed to B A Campbell.

At least 19 recordsLinked to original sources
PubMed2003

Kidney transplantation into an ileal conduit: a single center experience of 59 cases.

PURPOSE: Congenital and acquired conditions of the lower urinary tract can lead to renal failure requiring transplantation. Under these circumstances transplantation into a urinary diversion or an augmented bladder may be the only option. We report our experience with renal transplantation into ileal conduits in the last 22 years. MATERIALS AND METHODS: Between January 1980 and August 2002, 59 renal transplants were drained into an ileal conduit in 54 patients at our center, accounting for 2.3% of the total number of transplants during this period. Median patient age was 28 years (range 1 to 63) and 13 patients were children. There were 12 living related and 47 cadaveric kidneys transplanted. Spina bifida, the most common cause of end stage renal disease, was seen in 22 patients (41%). Patient and graft survival following transplantation into an ileal conduit were compared with that in the 2,579 other transplants done at this center between January 1980 and December 2001. RESULTS: Actuarial graft survival was 90% at 1 year, 63% at 5 years, 52% at 10 years and 52% at 15 years. Actuarial patient survival was 95% at 1 year, 83% at 5 years, 69% at 10 years and 69% at 15 years. Graft and patient survival was statistically similar to the outcome of the 2,579 other transplants done at our center between January 1980 and December 2001. At a mean followup of 4.6 years (range 0.1 to 20) mean serum creatinine in the 39 functioning grafts was 156 mmol/l. Of the surgical complications 21% were directly attributable to the ileal conduit and it could be considered a risk factor contributing to the complication in a further 39%. Symptomatic urinary tract infection was noted in 65% of the patients, although it did not lead to graft loss. At followup 7 patients had died with a functioning graft. Grafts were lost due to chronic allograft nephropathy in 3 cases, renal artery stenosis in 2, renal vein thrombosis in 2, and acute severe rejection, staghorn calculus and ureteroileal stricture in 1 each. CONCLUSIONS: Kidney transplant drainage into an ileal conduit for urinary diversion is an effective treatment for patients with end stage renal disease due to abnormal lower urinary tracts. Despite preexisting co-morbidity and the increased complication rate long-term graft and patient survival is comparable to that in the normal transplant population.

Adolescent↗
PubMed2001

Tacrolimus is not associated with gingival overgrowth in renal transplant patients.

BACKGROUND: Cyclosporin A is used extensively to prevent the rejection of allogenic renal transplants. However, it is associated with a variety of undesirable side effects including gingival overgrowth. Tacrolimus (FK506), has been marketed as an effective alternative immunosuppressant to cyclosporin A and recent subjective reports suggest patients taking it complain infrequently of gingival problems. This clinical investigation was undertaken to confirm whether or not tacrolimus adversely affected the gingival health of renal transplant recipients. METHODS: Renal transplant patients (RTPs) under the care of the Renal Transplantation Service at the Manchester Royal Infirmary, who had received a renal allograft at least 18 months earlier, were recruited for this study. All but one of the RTPs had been taking tacrolimus since transplantation. The other had commenced tacrolimus therapy two months after receiving her allograft. A hospital based control group was recruited from non transplanted individuals attending the Turner Dental School, Manchester. Each patient underwent a detailed dental assessment and had dental impressions taken. The extent of gingival overgrowth was determined from plaster models. RESULTS: 25 renal transplant recipients and 26 control patients were included in the study. None of the individuals in either the tacrolimus or control groups had clinically significant overgrowth. The patients in the tacrolimus group with the highest overgrowth scores were those also taking calcium antagonists as treatment for hypertension. CONCLUSION: This study demonstrates that tacrolimus has no adverse effects on the gingival tissues and thus has potential as an alternative immunosuppressant for individuals susceptible to developing cyclosporin A-induced gingival overgrowth.

Adult↗
PubMed2000

Three clusters of ciguatera poisoning: clinical manifestations and public health implications.

Between July 1997 and August 1998 we investigated three clusters (26 cases) of ciguatera poisoning in the inner Sydney area. Tropical reef fish were implicated in each cluster. Most of those affected had musculoskeletal, neurological and gastrointestinal symptoms. The clusters raise questions about the need for rapid diagnosis and enhanced surveillance mechanisms, the regulation of fish supply, and the lack of testing facilities for ciguatera toxin.

Adolescent↗
PubMed2000

The calcium channel blocker used with cyclosporin has an effect on gingival overgrowth.

BACKGROUND/AIMS: To investigate whether the choice of calcium channel blocker, used in conjunction with cyclosporin A, affected the prevalence of gingival overgrowth. METHOD: A cohort of 135 renal transplant recipients who had been medicated with cyclosporin A in combination with either nifedipine (89) or amlodipine (46) since transplant, took part in the study. The inclusion criteria were that eligible subjects had been in receipt of a kidney transplant for at least 12 months, had at least 10 teeth and had not received specialist periodontal treatment. The age, gender, current drug regimen and dosage were recorded for each participant and alginate impressions taken of both arches. The presence and severity of gingival overgrowth were scored from plaster models. RESULTS: A higher proportion (72%) of the amlodipine group were categorised as having gingival overgrowth compared with only 53% of the nifedipine group, chi square=4.5, p<0.05. Logistic regression analysis was used to explore the relationship between the presence or absence of gingival overgrowth (dependent variable) and age, gender, time since transplant, dose of cyclosporin A, centre in which the patient was treated, and the calcium channel blocker used (independent variables). Independent predictors of gingival overgrowth in this multivariate analysis were whether the individual was treated with amlodipine or nifedipine (p=0.01) and whether the individual was young or old (p=0.01). Within the multivariate analysis, the odds ratio for amlodipine to be associated with gingival overgrowth compared with nifedipine was 3.0 (confidence interval 1.3-6.9). CONCLUSIONS: The prevalence of gingival overgrowth in renal transplant recipients maintained on cyclosporin A and nifedipine is lower than those treated with cyclosporin A and amlodipine.

Adult↗
PubMed2000

Reduction in gingival overgrowth associated with conversion from cyclosporin A to tacrolimus.

BACKGROUND: Unsightly gingival overgrowth affects many individuals immunosuppressed with cyclosporin A (CsA). Current management involves repeated periodontal surgery and intensive hygienist support. Tacrolimus is an effective alternative immunosuppressive agent for renal transplantation which does not appear to produce gingival enlargement. AIMS: The purpose of the present study was to monitor the gingival response of 4 renal transplant patients (RTPs), with clinically significant CsA-induced gingival overgrowth, after their immunosuppressive therapy was switched to tacrolimus. METHODS: Intra-oral photographs and alginate impressions were taken both prior to the drug conversion and again, 6 to 9 months later. Gingival overgrowth scores were determined, from plaster models on both these occasions. RESULTS: All of the RTPs experienced significant resolution of their gingival enlargement within the time period studied; however, only one had complete regression. CONCLUSION: It is concluded that conversion of RTPs with gingival overgrowth from CsA to tacrolimus may provide an effective management strategy for this clinical problem.

Adolescent↗
PubMed1998

Inhibition of the expression of conditioned cardiac responses in the developing rat.

It is generally recognized that during development the capacity to express learning in terms of changes in somatomotor activity is evident earlier than the capacity for learned changes in autonomic responding (e.g., heart rate). In this series of experiments, findings indicate that changes in heart rate to a visual conditioned stimulus (CS) paired with a footshock unconditioned stimulus (US) can be observed as early in development in the rat as freezing responses. However, cardiac responses are inhibited from being expressed by preweanlings (but not adults) during CS-US pairings, the time when heart rate responses are often measured. This inhibition appears to arise from US exposure, and dissipates completely within 2 hr of training. These findings are discussed with respect to developmental changes in US-evoked autonomic arousal and response system dissociations.

Analysis of Variance↗
PubMed1998

Utilizing sonography to follow fetal growth.

In utero diagnosis of fetal growth abnormalities continues to pose a clinical dilemma. Although significant advances have been made in the understanding of growth disturbances and their clinical importance, false-positive and false-negative diagnoses of IUGR and excessive fetal growth continue to affect the accuracy of antenatal diagnosis. Until more accurate methods are developed to aid in diagnosis, multiple biometric parameters should be assessed in patients either at risk for or with a suspected growth disturbance. Serial measurements obtained every 2 to 3 weeks may enhance diagnostic capabilities. Although antenatal diagnosis of IUGR has been shown to be of benefit in improving outcome, more study is needed to determine whether there is a benefit in antenatal diagnosis of macrosomia or LGA.

Diagnosis, Differential↗
PubMed1997

Autonomic and behavioral correlates of appetitive conditioning in rats.

The cardiac responses accompanying conditioned stimulus- (CS)-generated (orienting) and unconditioned stimulus- (US)-generated appetitively motivated behaviors (P. C. Holland, 1977) were investigated. On the basis of contemporary psychophysiological research, CS-generated responses were predicted to produce bradycardia, and US-generated responses to produce tachycardia. Pairing a 10-s visual CS with food delivery produced conditioned behavioral orienting (rearing) during the initial portion of the CS, followed by magazine approach (US-generated) responses as the CS progressed. CS onset produced a decrease in heart rate, mediated by an increase in parasympathetic stimulation of the heart, which persisted throughout the 10-s CS; no support for a biphasic cardiac response was observed. These data are discussed with respect to other conditioned autonomic responses and their relevance to foraging and food ingestion.

Animals↗
PubMed1997

Emergence of conditioned cardiac responses to an olfactory CS paired with an acoustic startle UCS during development: form and autonomic origins.

Pairing an olfactory conditioned stimulus (CS) with an acoustic startle unconditioned stimulus (UCS) produced conditioned bradycardia in rats ranging from 12 days of age to adulthood but failed to produce conditioning in 10-day-olds (Experiment 1). The second experiment compared the effects of two different UCSs, acoustic startle and electric shock. The startle UCS produced conditioned bradycardia accompanied by immobility. In contrast, the shock UCS produced conditioned tachycardia accompanied by behavioral activation. Pharmacological analysis revealed that activation of the parasympathetic nervous system (PNS) produced the conditioned bradycardia (Experiment 3) and that activation of the sympathetic nervous system (SNS) produced the conditioned tachycardia (Hunt, Hess, & Campbell, 1994). Further comparisons revealed that the startle UCS established conditioning several days earlier in development than the shock UCS. The ability of the PNS to respond to phasic stimulation earlier in development than the SNS was discussed as a possible mechanism for the early development of conditioned bradycardia.

Acoustic Stimulation↗
PubMed1996

Developmental and pharmacological analysis of the cardiac response to an acoustic startle stimulus.

The purpose of this research was to study the cardiac response of preweanling and adult rats to 10 presentations of an acoustic startle stimulus (0 ms rise time, 100 ms, 130 dB, white noise stimulus). The first presentation of the startle stimulus produced a decrease in heart rate (HR) at both ages. With continued stimulus presentations, the response shifted to tachycardia in the adults but remained bradycardia in the preweanlings. Pharmacological analysis revealed that the startle stimulus activated only the parasympathetic system in the preweanling rats on all 10 trials. In contrast, the startle stimulus produced coactivation of the parasympathetic and sympathetic systems in the adults on the first trial, with the parasympathetic system predominating, and solely sympathetic activation on later trials. These results are discussed in terms of current psychophysiological models of (a) the cardiac response to startle stimuli and (b) autonomic space.

Acoustic Stimulation↗
PubMed1995

Delayed development of conditioned heart rate responses to auditory stimuli in the rat.

This study examined heart rate responses to an auditory conditioned stimulus during development in the rat. The unconditioned stimulus (US) in all experiments was an acoustic startle stimulus. The conditioned stimulus elicited a monophasic bradycardia in animals 21 days of age and older, but no response in younger animals. These results are strikingly similar to an earlier study that used shock as the US (Campbell & Ampuero, 1985). Further, the conditioned cardiac response in adults was found to be mediated entirely through activation of the parasympathetic division of the autonomic nervous system (ANS) even though the US unconditionally activates the sympathetic system at that age. The delayed development of several different forms of conditioned fear is discussed.

Acoustic Stimulation↗
PubMed1995

Megaloblastic anemia in pregnancy.

Megaloblastic anemia is one of the acquired nutritional anemias that may complicate pregnancy. It is most often secondary to folic acid deficiency because folate requirements are increased during gestation. When the diagnosis of megaloblastic anemia is confirmed, appropriate therapy will initiate a rapid reversal of the anemia process. Because of the association between neural tube defects and folate deficiency, it is recommended that women of reproductive age take folic acid supplementation.

Anemia, Megaloblastic↗
PubMed1994

The orienting response to brief auditory stimuli in preweanling and adult rats.

The cardiac orienting response to brief auditory stimuli was measured in preweanling and adult rats. The eliciting stimulus varied in duration (2 or 10 s) and complexity (continuous or pulsing). Stimulus complexity affected response magnitude with the pulsing stimulus eliciting a larger response than the continuous stimulus. Stimulus duration affected response persistence but only when a pulsing stimulus was used. In contrast to recent research with stimuli of much longer duration, age did not significantly affect any aspect of the cardiac response to the novel auditory stimuli in the present study. These results are discussed in terms of (1) the effects of stimulus duration on the heart-rate component of the orienting response and (2) two-stage models of attention.

Aging↗
PubMed1994

Delayed development of fear-potentiated startle in rats.

The developmental emergence of fear-potentiated startle was examined in rats ranging in age from 16 to 75 days. In Experiment 1, a pure tone served as the conditioned stimulus (CS) and an acoustic startle pulse served as the unconditioned stimulus (US) for fear conditioning. Fear-potentiated startle by the tone CS was observed in rats 23 days of age and older but not in rats 16 days of age. In Experiment 2, a light served as the CS. Rats 30 days of age and older showed fear-potentiated startle, whereas 23-day-old rats did not. The final experiment demonstrated that another behavioral index of fear, stimulus-elicited freezing, was observed earlier in development than fear-potentiated startle, confirming the effectiveness of the training procedure for conditioning fear. The results suggest that fear-potentiated startle is a relatively late-emerging response system, paralleling the development of conditioned autonomic changes (e.g., heart rate) rather than that of freezing.

Aging↗
PubMed1994

Paradoxical autonomic responses to aversive stimuli in the developing rat.

The goals of this research were to determine (a) the change in heart rate elicited by aversive auditory stimuli in the laboratory rat at different ages and (b) the autonomic origins of those changes at each age. The results of the first 2 experiments showed that aversive white noise stimuli elicited cardiac deceleration in preweanling (16-day-old) rats and cardiac acceleration in weanling (23-day-old), periadolescent (30-day-old), and adult (60-day-old) rats. Subsequent experiments showed that (a) the decrease in heart rate elicited by the noise stimulus in preweanling rats was mediated by parasympathetic activation of the heart, (b) the stimulus-elicited increase in heart rate elicited by the noise in periadolescent rats was mediated by parasympathetic withdrawal of the heart, and (c) the noise-induced increase in heart rate in adult rats was primarily mediated by sympathetic activation of the heart.

Acoustic Stimulation↗
PubMed1994

Vasovagal syncope and head upright tilt table testing.

Syncope is a common medical complaint that is responsible for a significant number of emergency department visits and hospitalizations each year. A majority of syncopal events are believed to be caused by vasovagal responses. Although vasovagal syncope is essentially equivalent to simple fainting, the physiologic events that lead to this phenomena are complex. Although not completely understood, the most commonly held theory explaining vasovagal syncope involves a series of reflexive interactions between cardiac mechanoreceptors and the autonomic nervous system. Until the advent of head upright tilt table testing, diagnosis of vasovagal syncope has been an assumption, made when all other causes have been eliminated. Tilt table testing allows reproduction of the syncopal event in susceptible individuals and monitoring of the patients' physiologic responses during an episode. Direct observation and documentation of symptoms permit accurate diagnosis and yield information vital to treatment and symptom control.

Autonomic Nervous System↗
PubMed1993

Reactivation of nonassociative memory.

The orienting response to an auditory stimulus, as measured by a decrease in heart rate, habituates rapidly, and at the same rate in preweanling and adult rats. Although adult rats retain this nonassociative memory for at least 7 days, preweanling rats show extremely rapid forgetting. In the preweanling, forgetting of this nonassociative memory appears to be complete after just 24 hr (Richardson & Campbell, 1991b). The results of several experiments in the present study with preweanling rats demonstrated that this type of nonassociative memory could be reactivated by presenting a fractional component of the original eliciting stimulus just prior to testing. The effectiveness of the reactivation treatment was critically dependent upon both the number of reactivating stimuli presented and the duration of those stimuli. Reactivation was also found to be stimulus-specific in that presentation of an auditory stimulus qualitatively different from that used in training (white noise instead of a pure tone) did not reactivate the memory. Control groups in each experiment demonstrated that the reactivation treatment facilitated retrieval of the prior nonassociative memory and did not produce new learning. A possible process through which nonassociative memories can be reactivated is discussed.

Animals↗