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Biomedical subjects

S Burton

Publications and source records attributed to S Burton.

At least 19 recordsLinked to original sources

The birth of a specialty: the first ten thousand patients of an old age psychiatry service.

BACKGROUND: Old age psychiatry as a clinical specialty emerged in the 1970s and modern, open-access multidisciplinary services started in the mid-1980s in South London. There are few accounts of referrals to old age psychiatry services and no quantitative accounts of the referral patterns to such teams. We report on the first 10,000 patients newly referred to the first such service in the world. METHODS: Observational study on routinely gathered data on age, gender, referral source, discipline of team member involved, diagnosis and duration of contact. Data validation was by iterative feedback to clinicians. RESULTS: Ten thousand patients were referred between December 1983 and March 2000. Missing data rates were low. The overall referral rate was 21.0 per 1000 population over 65 per annum, with the highest rate in those 85+ years old, in whom there was a marked rise over time. The rise in referral rate compensated for a decline in the population over 65 so that the numbers of referrals rose. Although there was a rise in the rate of referral of people with an organic diagnosis over time, this was not statistically significant. Organic patients constituted 50-60% of referrals but had shorter contact times than functional ones. Cause for concern included a low rate of referral from care homes, and a high proportion of possibly inappropriate referrals from medical and general psychiatry services. We were pleased to see no excess of such referrals from open-access sources, confirming earlier work. CONCLUSIONS: Descriptive data on referrals and workload of the first open-access multidisciplinary old age psychiatry service have generated cause for both celebration and concern.

Aged↗

Predictive poor prognostic factors in colonic carcinoma.

INTRODUCTION: Five-year survival in rectal cancer has been steadily improving since the introduction of neoadjuvant chemoradiation and total mesorectal excision surgery. In contrast, 5-year survival rates and management of colonic carcinoma remain relatively unchanged. This study aims to identify poor prognostic factors in colonic cancer patients that could potentially be predicted pre-operatively to identify a subset of patients amenable to neoadjuvant treatment strategies. METHODS: Database compilation of all operable rectal and colonic cancer patients presenting to a single district general hospital over 5 years. Data were documented on presentation and site of tumour, TNM staging, differentiation and extramural venous invasion. RESULTS: There was no significant difference in 4-year survival between rectal (57.5%) and right (57%) or left sided (52.5%) colonic cancers (p=0.4689). On multivariate analysis, N2-stage, T4-stage and emergency presentation were identified as independent prognostic factors. On univariate analysis, in addition to the above factors, presence of venous invasion (p=0.001) and poor differentiation (p=0.0003) of tumour also predicted for poor 5-year survival. CONCLUSION: T4-stage and N2-stage and extramural venous invasion are poor prognostic factors that could be identified pre-operatively with suitably accurate imaging. Such patients could then be considered for a pre-operative treatment strategy.

Adult↗

MRI directed multidisciplinary team preoperative treatment strategy: the way to eliminate positive circumferential margins?

Histopathological audit of positive circumferential resection margins (CRMs) can be used as a surrogate measure of the success of rectal cancer treatment. We audited CRM involvement in rectal cancer patients and the impact of the multidisciplinary team (MDT) on implementing a magnetic resonance imaging (MRI)-based preoperative treatment strategy. Data were collected on all newly diagnosed rectal cancer patients treated in our network between January 1999 and December 2002. Data were analysed for MRI prediction and histopathological assessment of CRM together with the MDT meeting treatment decisions. The CRM+ve rate of those discussed at MDT vs those not discussed were compared. We re-audited the CRM+ve rates 1 year after introducing a policy of mandatory preoperative MRI-based MDT discussion. Of the 298 patients diagnosed with rectal cancer, 39 (13%) were deemed palliative, 178 underwent surgery alone and 81 underwent neoadjuvant therapy. Of these, 62 out of 178 patients underwent surgery alone without MRI-based MDT discussion resulting in positive CRM in 16 cases (26%) as compared to 1 out of 116 (1%) in those patients with MDT discussion of MRI. Overall CRM+ve rate in all nonpalliative patients with or without MDT discussion was 12.5% (32 out of 256), significantly lower than the <20% rate (P<0.001) quoted in national guidelines. Re-audit in 98 consecutive patients following a change of policy produced a lower CRM+ve rate of 3% (1 out of 37) for all surgery alone patients and an overall CRM+ve rate of 7% (5 out of 70). In conclusion, MDT discussion of MRI and implementation of a preoperative treatment strategy results in significantly reduced positive CRM in rectal cancer patients.

Adult↗

Sentinel node biopsy should be supplemented by axillary sampling in patients with small breast cancers.

Axillary clearance provides important prognostic information but is associated with significant morbidity. Sentinel node biopsy can provide staging .141 patients with node negative early breast cancers-tumour size less than 1.5 cm measured clinically or by imaging had guided axillary sampling (sentinel lymph node biopsy in combination with axillary sampling). Four node axillary sampling improved the detection rate of axillary node metastases by 13.6% as compared to blue dye sentinel node biopsy alone. Positive sampled nodes strongly indicated the likelihood of further metastatic being revealed by axillary dissection (67%). Negative sampled nodes in combination with a positive sentinel node biopsy were associated with a much lower rate of further nodal involvement in the axillary clearance (8%).

Journal Article↗

Influence of oxygen tension on nitric oxide and prostaglandin E2 synthesis by bovine chondrocytes.

OBJECTIVES: To determine the in vitro effects of oxygen tension on interleukin (IL)-1beta induced nitric oxide (*NO) and prostaglandin E(2) (PGE(2)) production by bovine chondrocytes. DESIGN: Enzymatically isolated bovine chondrocytes were cultured for different periods in suspension in 21 (atmospheric), 5 or 1% (low) oxygen tension and in the absence or in the presence of increased amounts (0.01 to 1nM) of IL-1beta. Nitrite and nitrate concentrations in the culture supernatants were determined by a spectrophotometric method based upon the Griess reaction. PGE(2) production was quantified by a specific radioimmunoassay (RIA). Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) mRNA steady state levels were also quantified by real-time polymerase chain reaction (PCR). RESULTS: In the absence of IL-1beta, ()NO production remained stable whatever the oxygen tension used. IL-1beta dose-dependently increased *NO production in both atmospheric and low oxygen conditions but the effect was more pronounced in low (1 and 5%) than in atmospheric (21%) oxygen tension (P<0.001). Under low and atmospheric oxygen tension, iNOS gene expression was increased by IL-1beta, but to a lesser extent in 21% than in 1 or 5% oxygen (P<0.01). In the basal condition, bovine chondrocytes spontaneously produced PGE(2) whatever the oxygen tension used. At 21% oxygen, IL-1beta dose-dependently increased PGE(2) production while no significant effect was observed at 1 or 5% oxygen. COX-2 gene expression was significantly upregulated by IL-1beta in both low and atmospheric oxygen tension. No significant difference between oxygen tension conditions was observed. CONCLUSIONS: This study demonstrates that a hypoxic environment fully blocks COX-2 activity but favours iNOS gene expression in chondrocytes culture. These findings indicate that O(2) tension modulates cellular behaviour in culture and supports the concept of chondrocyte culture in low oxygen tension to reproduce in vitro the life conditions of chondrocytes.

Animals↗

A critical process analysis of wine production to improve cost, quality and environmental performance.

Abstract Wine production in South Africa is delocalised, with numerous small-to-medium sized producers within several regions within the Western Cape. Whilst adapting to new technological changes, producers have to respond to pressure from consumers and governments regarding the environmental consequences of winemaking, especially water usage and pollution. To date, no systematic analysis integrating the various aspects of winemaking in South Africa has been done. This study assessed both physical inputs and outputs. A detailed questionnaire was developed to broadly assess these parameters and was submitted to all cellars in South Africa. Case studies were performed at three cellars during the 2002 harvest season to validate the questionnaires and collect missing information. Based on this, and a cocurrent project, the following parameters were correlated to the tons of grapes presses per annum: effluent parameters which include chemical oxygen demand, suspended solids, total dissolved solids, sodium adsorption ratio, quantity of effluent; wine produced, water consumed, and electricity consumed. These parameters were used to develop an input/output model. This model may be used by wineries to predict their water and electrical consumption, wine produced and effluent characteristics provided they know the tonnage of grapes pressed per year.

Agriculture↗

Formulation and in vitro evaluation of transdermal patches of melatonin.

The present study was undertaken to prepare and evaluate monolithic drug-inadhesive type transdermal patches of melatonin containing penetration enhancers such as fatty alcohols, fatty acids, and terpenes. The patches were prepared using Eudragit E 100 as the adhesive polymer. The release profile of melatonin from control as well as enhancer-containing patches showed an initial burst of melatonin release for up to 4 hours and then a plateau after 8 hours. The release profiles of melatonin from patches containing various enhancers were similar to the control patch. However, the addition of enhancers in the patch increased the permeation of melatonin through hairless rat skin. The flux values of patches containing octanol, nonanoic acid, and myristic acid were higher than the control patch (no enhancer), but the differences were not statistically significant (P>0.05). Decanol, myristyl alcohol, and undecanoic acid at 5% concentrations showed significantly higher flux values through hairless rat skin (enhancement ratios 1.7, 1.5, and 1.6 for decanol, myristyl alcohol, and undecanoic acid, respectively) (P<0.05). Menthol and limonene at 5% w/w showed maximum permeation of melatonin among all enhancers studied (enhancement ratios=2.1 and 2.0 for menthol and limonene, respectively) (P<0.001). In general, there was about 4-6 hours of lag time observed before a steady state flux of melatonin was achieved. Though the flux of melatonin observed in the present study is 5-10 times higher than the required delivery rate in humans, it must be noted that the present study was performed using hairless rat skin, which is generally more permeable compared to human skin. Further studies using human skin would prove the usefulness of these patches.

Acrylates↗

The Lap-Band system in the United States: one surgeon's experience with 271 patients.

BACKGROUND: The LAP-BAND system is considered an important bariatric surgery procedure in many countries and is rapidly gaining acceptance in the United States. Outcomes data emerging in the United States parallel European and Australian experience. The purpose of this study was to examine our experience with this procedure in the United States. METHODS: Between November 2000 and September 2002, 271 patients (236 women) underwent LAP-BAND system placement. The mean age of patients was 40 years (18-63); preoperative mean body weight was 125 kg (93-192). Surgeries were performed using either the two-step (pars flaccida to perigastric) or the pars flaccida technique with three (1.1%) conversions to open procedures. Mean operative time was 42 min (23-86); average hospital stay was 1 day (4 h to 7 days). RESULTS: The mean body mass index (BMI) decreased from a baseline of 45.3 kg/m(2) (35-68) to 41.9 ( n = 178), 39.5 ( n = 101), 38.4 (n = 81), 36.5 (n = 72), 35.9 (n = 51), and 35.1 (n = 21) kg/m(2) at 3, 6, 9, 12, 18, and 24 months, respectively, after surgery. Mean excess weight loss was 40% at 12 months and 43% at 24 months. As patients lost weight, comorbid conditions improved. No deaths occurred, no bands had to be removed, and postoperative complications were minor: 20 (7.3%) access port problems, 18 (6.6%) gastric pouch dilatations, five (1.8%) gastric slippages, and five (1.8%) stoma obstructions. All were managed conservatively or repaired laparoscopically using the original bands. Additional complications included four cases of pneumonia and one case of pulmonary embolism. One patient required reoperation because of trocar site bleeding. CONCLUSIONS: The LAP-BAND system is a safe and effective bariatric procedure leading to considerable weight loss and reduction in comorbidity.

Adolescent↗

Reliability of pre-operative biopsies in the histological grading of colorectal adenocarcinomas.

BACKGROUND: Management of colorectal cancer depends on many patient and tumour variables. Decisions are sometimes based on the histological grade of tumour as assessed by initial biopsy. This retrospective study looked at the reliability of grading colorectal cancer from pre-operative biopsies. METHODS: 118 patients with a diagnosis of colorectal cancer, who had adequate pre-operative biopsies, were included in the study. A single consultant histopathologist re-examined all the preoperative biopsy slides, but was blinded to the final grading of the resection specimen. RESULTS: Of the 118 resection specimens, 41 were graded well-differentiated, 52 moderately differentiated and 25 poorly differentiated. When compared with postoperative grading, 37 (31%) initial biopsies were undergraded, 49 (43%) were correctly graded and 32 (26%) were overgraded. CONCLUSIONS: These results suggest that the histological grading of pre-operative specimens is inaccurate and should be used with caution to determine treatment. The difficulty with grading pre-operative biopsies in colorectal cancer may be owing to a lack of specific criteria such as is used in, for example, breast cancer.

Adenocarcinoma↗

Microdochectomy in women aged over 50 years.

Management of a spontaneous single duct nipple discharge without associated mass and normal mammography remains controversial. Our study examined the pathological results of 52 women of all ages treated with microdochectomy for single duct nipple discharge. Malignant or premalignant lesions were identified in 1 patient under 50 years of age and 2 patients over 50 years. Papilloma was the most frequently identified pathology in both age groups (60% of patients under 50 years and 73% over or equal to 50 years of age). Our results suggest that microdochectomy is a safe effective treatment in women aged over 50 years.

Adult↗

Percutaneous permeation and skin irritation of JP-8+100 jet fuel in a porcine model.

JP-8 is the major jet fuel used by US Air Force. JP-8+100 is a new jet fuel recently introduced by the US Air Force, which contains JP-8 plus three performance additives [butylated hydroxytoluene (BHT), metal deactivator (MDA) and 8Q405]. The purpose of the present study was to investigate the percutaneous permeation of JP-8+100 across pig ear skin in vitro and to study the effect of JP-8+100 exposure on the skin barrier function, moisture content and irritation in Yucatan minipigs. The influence of performance additives on the permeation of JP-8 was studied by adding each additive individually to JP-8. The percutaneous permeation and skin irritation data obtained with JP-8+100 were compared with that of JP-8. JP-8+100 spiked with 5.0 microCi of radiolabeled [14C]tridecane, nonane, naphthalene or toluene (selected components of JP-8+100) was used for the in vitro percutaneous permeation studies. For skin irritation studies, 250 microl of JP-8+100 was placed in a Hill top chamber and affixed over the marked treatment area for 24 h. The components of JP-8+100 such as tridecane, nonane, naphthalene and toluene permeated readily through pig ear skin without any apparent lag time. Compared to JP-8, the permeation of tridecane, toluene and nonane from JP-8+100 was significantly lower (P<0.05). However, the permeation of naphthalene from JP-8+100 was significantly higher than from JP-8. When BHT was added to JP-8, the permeation of all four chemicals were significantly decreased (P<0.05). Though the addition of 8Q405 to JP-8 decreased the permeation of all four chemicals, the values were not significantly different (P>0.05) from that of JP-8. Addition of MDA did not show any significant change in the permeation of the selected chemicals from JP-8. Application of JP-8+100 increased the transepidermal water loss (TEWL) about three times compared to the baseline level. The skin moisture content decreased consistently after the application of JP-8+100, though it was not significantly different (P>0.05) from the baseline level. JP-8+100 caused a moderate erythema (score: 1.60) and a moderate to severe edema (score: 2.60). These results suggest that JP-8+100 produces significant changes in the barrier function of the skin and a local irritant effect upon occlusive dermal exposure. However there was no significant difference in the skin irritation data observed from JP-8 and JP-8+100.

Administration, Cutaneous↗

Design and assembly of solid-phases for the effective recovery of nanoparticulate bioproducts in fluidised bed contactors.

Practical recovery of nanoparticulate bioproducts from suspension feedstocks has been studied in batch, fixed bed and fluidised bed adsorptive contactors. The performance of five discrete configurations of adsorbent solid phase has been critically evaluated in the anion exchange recovery of mg quantities of BSA nanoparticles. These have served as surrogate size mimics of less easily sourced viral and plasmid gene therapy vectors, characterised by high value and a shortage of supply in quantities sufficient for research and development. Performance parameters of binding capacity, efficacy of washing, desorption efficiency and total cycle time were strongly influenced by the external and internal topographies of solid phases, together with the localised concentrations of interacting chemical ligands which modulate adsorption. In respect of a full operational recovery cycle, porous adsorbents developed for refined chromatographic fractionation of macromolecules, appear less suited overall than solid, nonporous particles, or solid particles coated with a shallow pellicle of active adsorbent material. Such findings have been confirmed in a detailed demonstration of the recovery of plasmid DNA (7.8 Kb) from chemical lysates of Escherichia coli.

Adsorption↗

Healthy city projects in developing countries: the first evaluation.

The 'healthy city' concept has only recently been adopted in developing countries. From 1995 to 1999, the World Health Organization (WHO), Geneva, supported healthy city projects (HCPs) in Cox's Bazar (Bangladesh), Dar es Salaam (Tanzania), Fayoum (Egypt), Managua (Nicaragua) and Quetta (Pakistan). The authors evaluated four of these projects, representing the first major evaluation of HCPs in developing countries. Methods used were stakeholder analysis, workshops, document analysis and interviews with 102 managers/implementers and 103 intended beneficiaries. Municipal health plan development (one of the main components of the healthy city strategy) in these cities was limited, which is a similar finding to evaluations of HCPs in Europe. The main activities selected by the projects were awareness raising and environmental improvements, particularly solid waste disposal. Two of the cities effectively used the 'settings' approach of the healthy city concept, whereby places such as markets and schools are targeted. The evaluation found that stakeholder involvement varied in relation to: (i) the level of knowledge of the project; (ii) the project office location; (iii) the project management structure; and (iv) type of activities (ranging from low stakeholder involvement in capital-intensive infrastructure projects, to high in some settings-type activities). There was evidence to suggest that understanding of environment-health links was increased across stakeholders. There was limited political commitment to the healthy city projects, perhaps due to the fact that most of the municipalities had not requested the projects. Consequently, the projects had little influence on written/expressed municipal policies. Some of the projects mobilized considerable resources, and most projects achieved effective intersectoral collaboration. WHO support enabled the project coordinators to network at national and international levels, and the capacity of these individuals (although not necessarily their institutions) was increased by the project. The average annual running cost of the projects was approximately 132,000 US dollars per city, which is close to the costs of the only other HCP for which a cost analysis has been undertaken, Bangkok (115,000 US dollars per year) Recommendations for these and other HCPs are provided.

Community Health Planning↗

Androgen deficiency in women with hypopituitarism.

Androgen deficiency in men is associated with severe osteopenia, alterations in body composition including an increase in fat mass, and decreased libido. Little is known about the pathophysiology, metabolic consequences, or gender-specific effects of androgen deficiency in women. Acquired hypopituitarism in women is characterized by central hypogonadism and/or hypoadrenalism and therefore may affect critical sources of androgen production in women. We hypothesized that serum androgen levels would be decreased in women with hypopituitarism. We therefore determined serum androgen levels in 55 women with hypopituitarism and 92 controls. This included 4 subsets of hypopituitary women: 1) women less than 50 yr old not receiving estrogen, 2) women less than 50 yr old receiving estrogen, 3) women more than 50 yr old not receiving estrogen, and 4) women more than 50 yr old receiving estrogen. Premenopausal controls with regular menstrual cycles were studied in the early follicular phase, midcycle, and luteal phase during one cycle. All other subjects were studied 3 times during the month at comparable intervals to mimic these 3 time points of the normal menstrual cycle. Serum testosterone, free testosterone, androstenedione, and dehydroepiandrosterone sulfate levels were markedly reduced in all 4 groups of women with hypopituitarism compared with controls (P < 0.0001). Moreover, serum testosterone, free testosterone, and androstenedione levels were lower in women with central hypoadrenalism and hypogonadism than in subjects with hypoadrenalism or hypogonadism alone (P < 0.025). Mean DHEAS levels were decreased in hypopituitary women with both hypogonadism and hypoadrenalism compared with those in women with hypogonadism alone (P < 0.0001). These data demonstrate hypoandrogenemia in women with hypopituitarism. The physiological consequences of low androgen levels in this population remain to be determined.

Adenoma↗

Mutation analysis of the entire PKD1 gene: genetic and diagnostic implications.

Mutation screening of the major autosomal dominant polycystic kidney disease (ADPKD) locus, PKD1, has proved difficult because of the large transcript and complex reiterated gene region. We have developed methods, employing long polymerase chain reaction (PCR) and specific reverse transcription-PCR, to amplify all of the PKD1 coding area. The gene was screened for mutations in 131 unrelated patients with ADPKD, using the protein-truncation test and direct sequencing. Mutations were identified in 57 families, and, including 24 previously characterized changes from this cohort, a detection rate of 52.3% was achieved in 155 families. Mutations were found in all areas of the gene, from exons 1 to 46, with no clear hotspot identified. There was no significant difference in mutation frequency between the single-copy and duplicated areas, but mutations were more than twice as frequent in the 3' half of the gene, compared with the 5' half. The majority of changes were predicted to truncate the protein through nonsense mutations (32%), insertions or deletions (29.6%), or splicing changes (6.2%), although the figures were biased by the methods employed, and, in sequenced areas, approximately 50% of all mutations were missense or in-frame. Studies elsewhere have suggested that gene conversion may be a significant cause of mutation at PKD1, but only 3 of 69 different mutations matched PKD1-like HG sequence. A relatively high rate of new PKD1 mutation was calculated, 1.8x10-5 mutations per generation, consistent with the many different mutations identified (69 in 81 pedigrees) and suggesting significant selection against mutant alleles. The mutation detection rate, in this study, of >50% is comparable to that achieved for other large multiexon genes and shows the feasibility of genetic diagnosis in this disorder.

Alleles↗

Salvage radiotherapy for prostate cancer recurrence after cryosurgical ablation.

OBJECTIVES: To retrospectively determine the outcome of patients treated with salvage three-dimensional conformal radiotherapy (RT) for prostate cancer recurrence after cryosurgical ablation of the prostate (CSAP). Biochemical control rates and morbidity were analyzed. METHODS: Between January 1990 and November 1999, a total of 49 patients initially treated with CSAP were later irradiated because of a rising prostate-specific antigen (PSA) level and/or a positive biopsy at Allegheny General Hospital. The clinical stage before cryosurgery was T1c in 7 patients; T2a in 7 patients; T2b in 10 patients; T3 in 17 patients; and T4 and/or N1 in 8 patients. The Gleason score was 6 or lower in 29 patients, 7 in 11 patients, and 8 or higher in 9 patients. The mean pre-CSAP PSA level was 15.7 ng/mL (range 2.4 to 45). One patient had a PSA level less than 4 ng/mL, 16 had a PSA level of 4 to 10 ng/mL, 21 had a PSA level of 10 to 20 ng/mL, and 11 had a PSA level greater than 20 ng/mL. Before the start of RT, a complete restaging workup was performed and was negative for distant metastatic disease in all 49 patients. The mean interval to recurrence after CSAP was 19 months (range 3 to 78). The mean RT dose to the planning target volume was 62.9 Gy (range 50.4 to 68.4). RESULTS: The mean pre-RT PSA level was 2.4 ng/mL (range 0.1 to 7.4). After RT, the mean nadir PSA level was 0.4 ng/mL (range 0 to 4.2). The mean time to PSA nadir was 5.8 months (range 1 to 15). In 42 patients, the PSA nadir was less than 1.0 ng/mL, in 5 patients the PSA nadir was greater than 1 ng/mL, and in 2 patients the PSA level remained stable. With a median follow-up time of 32 months (range 12 to 85), the overall biochemical control rate was 61%. The mean time to biochemical failure was 14.5 months (range 1 to 47). Of 30 patients with a pre-RT PSA level of 2.5 ng/mL or less, the disease of 22 (73%) was controlled compared with only 8 (42%) of 19 with a pre-RT PSA level greater than 2.5 ng/mL (P = 0.040). Biochemical control occurred in 18 (69%) of 26 patients with a dose of 64 Gy or greater compared with only 12 (52%) of 23 patients with a dose of less than 64 Gy (P = 0.024). The disease of 20 (70%) of 29 patients with a Gleason score of 6 or lower was controlled versus 10 (50%) of 20 patients with a Gleason score of 7 or greater (P = 0.064). Only 2 patients developed subacute morbidity (proctitis and a urethral stricture). All complications resolved with conservative measures. CONCLUSIONS: Salvage RT for prostate cancer recurrence after CSAP appears feasible. Our preliminary experience revealed that post-CSAP RT in patients with prostate cancer appears to effectively diminish the post-RT PSA level to a nadir of 1.0 ng/mL or less in most patients. The pre-RT PSA level and radiation dose may be important predictors of biochemical control in the salvage setting. RT as described was associated with minimal toxicity to the gastrointestinal/genitourinary systems. Additional prospective randomized studies are necessary to better assess the role of RT in the treatment of these patients.

Aged↗

Combined lesions of hippocampus and subiculum Do not produce deficits in a nonspatial social olfactory memory task.

Rats transmit information to each other about which foods are safe to eat. If a rat smells a food odor on the breath of another rat, it is subsequently more likely to eat that food than an alternative. Work by Galef et al. (1988) has shown that the observer rat forms an association between two olfactory stimuli on the breath of the demonstrator rat that has eaten the food, the food odor and carbon disulphide, which is normally present in the rat breath. Bunsey and Eichenbaum (1995) claimed that the hippocampus/subicular region is required for the long-term retention of this nonspatial form of associative memory on the basis that combined lesions of the hippocampus and subiculum produced a deficit, but lesions of either structure alone did not. We report here a failure to repeat this finding. Rats with either combined lesions of the hippocampus and subiculum or with amygdala lesions were tested on their ability to remember this association either immediately (testing short-term memory) or after a 24 hr delay (testing long-term memory). Neither lesion group exhibited significant memory deficits on this nonspatial associative task at either test interval. In contrast, a deficit was observed on a spatial memory task (forced-choice alternation t-maze) for animals with combined lesions of the hippocampus and subiculum. These results contradict the findings of Bunsey and Eichenbaum (1995) and support the idea that the hippocampus/subicular region is not required for this nonspatial associative memory.

Amygdala↗